U.S. patent application number 12/161295 was filed with the patent office on 2010-09-09 for resin composition, molded article, and production methods thereof.
This patent application is currently assigned to TEIJIN CHEMICALS LTD.. Invention is credited to Katsuhiko Hironaka, Keiichiro Ino, Fumitaka Kondo, Yuichi Matsuno, Hirotaka Suzuki, Kiyotsuna Toyohara.
Application Number | 20100227963 12/161295 |
Document ID | / |
Family ID | 38287761 |
Filed Date | 2010-09-09 |
United States Patent
Application |
20100227963 |
Kind Code |
A1 |
Hironaka; Katsuhiko ; et
al. |
September 9, 2010 |
RESIN COMPOSITION, MOLDED ARTICLE, AND PRODUCTION METHODS
THEREOF
Abstract
There are provided a resin composition comprising a polylactic
acid which (i) comprises a poly-L-lactic acid (component B-1) and a
poly-D-lactic acid (component B-4), (ii) has a weight ratio of the
component B-1 to the component B-4 (component B-1/component B-4) of
10/90 to 90/10, and (iii) shows a proportion of melt peaks at
195.degree. C. or higher to all melt peaks in a temperature rising
process in measurement by a differential scanning calorimeter (DSC)
of at least 20%; a molded article of the resin composition; and
methods for producing the resin composition and the molded
article.
Inventors: |
Hironaka; Katsuhiko;
(Chiyoda-ku, JP) ; Kondo; Fumitaka; (Chiyoda-ku,
JP) ; Ino; Keiichiro; (Chiyoda-ku, JP) ;
Matsuno; Yuichi; (Chiyoda-ku, JP) ; Toyohara;
Kiyotsuna; (Iwakuni-shi, JP) ; Suzuki; Hirotaka;
(Iwakuni-shi, JP) |
Correspondence
Address: |
SUGHRUE MION, PLLC
2100 PENNSYLVANIA AVENUE, N.W., SUITE 800
WASHINGTON
DC
20037
US
|
Assignee: |
TEIJIN CHEMICALS LTD.
Chiyoda-ku, Tokyo
JP
TEIJIN LIMITED
Osaka-shi, Osaka
JP
|
Family ID: |
38287761 |
Appl. No.: |
12/161295 |
Filed: |
January 17, 2007 |
PCT Filed: |
January 17, 2007 |
PCT NO: |
PCT/JP2007/051023 |
371 Date: |
July 17, 2008 |
Current U.S.
Class: |
524/451 ;
264/328.1; 264/500; 524/508; 524/537; 525/190; 525/450 |
Current CPC
Class: |
C08L 23/02 20130101;
C08L 23/02 20130101; C08L 69/00 20130101; C08K 5/51 20130101; C08K
3/34 20130101; C08L 69/00 20130101; C08L 25/04 20130101; C08L 67/04
20130101; C08K 3/013 20180101; C08K 3/013 20180101; C08L 67/02
20130101; C08L 67/02 20130101; C08L 67/04 20130101; C08L 67/04
20130101; C08L 2666/18 20130101; C08L 2666/18 20130101; C08L
2666/18 20130101; C08L 2666/18 20130101 |
Class at
Publication: |
524/451 ;
525/450; 525/190; 524/537; 524/508; 264/328.1; 264/500 |
International
Class: |
C08L 69/00 20060101
C08L069/00; C08L 73/00 20060101 C08L073/00; C08K 3/34 20060101
C08K003/34; B29C 45/00 20060101 B29C045/00; B29C 49/00 20060101
B29C049/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 18, 2006 |
JP |
2006-009758 |
Jan 19, 2006 |
JP |
2006-011005 |
Jan 20, 2006 |
JP |
2006-012310 |
Claims
1. A resin composition comprising 100 parts by weight of
thermoplastic resin (component A) and 1 to 200 parts by weight of
polylactic acid (component B), wherein (i) the component B
comprises a polylactic acid (component B-1) that comprises 90 to
100 mol % of L-lactic acid unit and 0 to 10 mol % of D-lactic acid
unit and/or units other than lactic acid and a polylactic acid
(component B-4) that comprises 90 to 100 mol % of D-lactic acid
unit and 0 to 10 mol % of L-lactic acid unit and/or units other
than lactic acid, (ii) the weight ratio of the component B-1 to
component B-4 (component B-1/component B-4) in the component B is
within a range of 10/90 to 90/10, and (iii) the component B in the
resin composition shows a proportion of melt peaks at 195.degree.
C. or higher to all melt peaks in a temperature rising process in
measurement by a differential scanning calorimeter (DSC) of at
least 20%.
2. The composition of claim 1, wherein the component A is at least
one resin selected from the group consisting of an aromatic
polycarbonate resin, a polyester resin, a polyolefin resin and a
styrene resin.
3. The composition of claim 1, wherein the component A is an
aromatic polycarbonate resin.
4. The composition of claim 3, wherein the aromatic polycarbonate
resin is bisphenol A based polycarbonate resin.
5. The composition of claim 1, wherein the component B in the resin
composition shows a proportion of melt peaks at 195.degree. C. or
higher to all melt peaks in a temperature rising process in
measurement by a differential scanning calorimeter (DSC) of at
least 70%.
6. The composition of claim 1, comprising 0.01 to 5 parts by weight
of crystal nucleating agent (component C) based on 100 parts by
weight of the component B.
7. The composition of claim 6, wherein the crystal nucleating agent
(component C) is talc.
8. The composition of claim 1, comprising 0.3 to 200 parts by
weight of inorganic filler (component D) based on 100 parts by
weight of the component A.
9. The composition of claim 1, comprising 0.01 to 5 parts by weight
of terminal blocking agent (component E) based on 100 parts by
weight of the component B.
10. A method for producing a resin composition by melt-kneading 100
parts by weight of thermoplastic resin (component A) and 1 to 200
parts by weight of polylactic acid (component B), wherein (i) the
component B comprises a polylactic acid (component B-1) that
comprises 90 to 100 mol % of L-lactic acid unit and 0 to 10 mol %
of D-lactic acid unit and/or units other than lactic acid and a
polylactic acid (component B-4) that comprises 90 to 100 mol % of
D-lactic acid unit and 0 to 10 mol % of L-lactic acid unit and/or
units other than lactic acid, (ii) the weight ratio of the
component B-1 to component B-4 (component B-1/component B-4) in the
component B is within a range of 10/90 to 90/10, and (iii) the
component B shows a proportion of melt peaks at 195.degree. C. or
higher to all melt peaks in a temperature rising process in
measurement by a differential scanning calorimeter (DSC) of at
least 20%.
11. The method of claim 10, wherein the component B shows a
proportion of melt peaks at 195.degree. C. or higher to all melt
peaks in a temperature rising process in measurement by a
differential scanning calorimeter (DSC) of at least 70%.
12. The method of claim 10, wherein the component B is obtained by
melt-kneading the component B-1 and the component B-4 at 245 to
300.degree. C.
13. The method of claim 10, wherein melt-kneading is carried out in
the presence of 0.01 to 5 parts by weight of crystal nucleating
agent (component C) based on 100 parts by weight of the component
B.
14. The method of claim 13, wherein the component C is talc.
15. The method of claim 10, wherein melt-kneading is carried out in
the presence of 0.3 to 200 parts by weight of inorganic filler
(component D) based on 100 parts by weight of the component A.
16. The method of claim 10, wherein melt-kneading is carried out in
the presence of 0.01 to 5 parts by weight of terminal blocking
agent (component E) based on 100 parts by weight of the component
B.
17. A molded article comprising the composition of claim 1.
18. The molded article of claim 17, which is an injection-molded
article.
19. The molded article of claim 17, which is an automobile part, an
electric/electronic part, an electrical equipment exterior part, an
office automation equipment exterior part or an optical disk
substrate.
20. A molded article comprising a polylactic acid (component B)
that shows a proportion of melt peaks at 195.degree. C. or higher
to all melt peaks in a temperature rising process in measurement by
a differential scanning calorimeter (DSC) of at least 20%.
21. The molded article of claim 20, comprising a polylactic acid
(component B) that shows a proportion of melt peaks at 195.degree.
C. or higher to all melt peaks in a temperature rising process in
measurement by a differential scanning calorimeter (DSC) of at
least 70%.
22. The molded article of claim 20, wherein the component B
comprises a polylactic acid (component B-1) that comprises 90 to
100 mol % of L-lactic acid unit and 0 to 10 mol % of D-lactic acid
unit and/or units other than lactic acid and a polylactic acid
(component B-4) that comprises 90 to 100 mol % of D-lactic acid
unit and 0 to 10 mol % of L-lactic acid unit and/or units other
than lactic acid, and the weight ratio of the component B-1 to the
component B-4 (component B-1/component B-4) is within a range of
10/90 to 90/10.
23. The molded article of claim 20, comprising 0.01 to 5 parts by
weight of crystal nucleating agent (component C) based on 100 parts
by weight of the component B.
24. The molded article of claim 23, wherein the component C is
talc.
25. The molded article of claim 20, which is in a block shape.
26. The molded article of claim 20, comprising 0.3 to 200 parts by
weight of inorganic filler (component D) based on 100 parts by
weight of the component B.
27. The molded article of claim 20, comprising 0.01 to 5 parts by
weight of terminal blocking agent (component E) based on 100 parts
by weight of the component B.
28. The molded article of claim 20, which is an automobile part, an
electric/electronic part, an electrical equipment exterior part, an
office automation equipment exterior part or an optical disk
substrate.
29. A method for producing a molded article by molding pellets
comprising a polylactic acid (component B) that shows a proportion
of melt peaks at 195.degree. C. or higher to all melt peaks in a
temperature rising process in measurement by a differential
scanning calorimeter (DSC) of at least 70%.
30. The method of claim 29, wherein the component B comprises a
polylactic acid (component B-1) that comprises 90 to 100 mol % of
L-lactic acid unit and 0 to 10 mol % of D-lactic acid unit and/or
units other than lactic acid and a polylactic acid (component B-4)
that comprises 90 to 100 mol % of D-lactic acid unit and 0 to 10
mol % of L-lactic acid unit and/or units other than lactic acid,
and the weight ratio of the component B-1 to the component B-4
(component B-1/component B-4) is within a range of 10/90 to
90/10.
31. The method of claim 29, wherein the component B is a polylactic
acid obtained by kneading the component B-1 and the component B-4
at 245 to 300.degree. C.
32. The method of claim 29, wherein the pellets comprise 0.01 to 5
parts by weight of crystal nucleating agent (component C) based on
100 parts by weight of the component B.
33. The method of claim 32, wherein the component C is talc.
34. The method of claim 29, wherein the pellets comprise 0.3 to 200
parts by weight of inorganic filler (component D) based on 100
parts by weight of the component B.
35. The method of claim 29, wherein the pellets comprise 0.01 to 5
parts by weight of terminal blocking agent (component E) based on
100 parts by weight of the component B.
36. The method of claim 29, wherein molding is carried out by
injection molding, extrusion, heat molding, blow molding or foam
molding.
37. The method of claim 36, wherein injection molding is carried
out at a mold temperature of 80 to 130.degree. C.
38. The method of claim 36, wherein a resin obtained by melting the
pellets at 200.degree. C. or higher is extruded.
39. The method of claim 38, wherein an obtained molded article is
heat-treated within a temperature range of its crystallization
temperature to melting point.
40. The method of claim 36, wherein after a resin obtained by
melting the pellets at 200.degree. C. or higher is extruded through
a slit die to obtain a sheet-shaped extruded article, the extruded
article is first heated to its glass transition temperature or
higher and then heat-molded.
41. The method of claim 40, wherein an obtained molded article is
heat-treated within a temperature range of its crystallization
temperature to melting point.
42. The method of claim 36, wherein after a resin obtained by
melting the pellets at 200.degree. C. or higher is molded to form a
parison, the parison is first heated to its glass transition
temperature or higher and then blow-molded.
43. The method of claim 42, wherein an obtained molded article is
heat-treated within a temperature range of its crystallization
temperature to melting point.
44. The method of claim 36, wherein a resin obtained by melting the
pellets at 160.degree. C. or higher is foam-molded.
45. The method of claim 44, wherein an obtained molded article is
heat-treated within a temperature range of its crystallization
temperature to melting point.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a resin composition and a
molded article that contain a polymer obtained from biomass
resources. More specifically, it relates to a resin composition
that contains a specific polylactic acid and has excellent heat
resistance and hydrolysis resistance, and a molded article of the
resin composition.
BACKGROUND OF THE ART
[0002] Thermoplastic resins have excellent heat resistance,
mechanical properties, impact resistance and dimensional stability
and are widely used in fields such as an office automation
equipment field, automobile field and electric/electronic part
field. On the other hand, however, the thermoplastic resins also
have an aspect that most of raw materials thereof rely on oil
resources.
[0003] In recent years, in view of fear of exhaustion of the oil
resources and a problem of increase of carbon dioxide in air that
causes global warming, carbon-neutral biomass resources that do not
rely on oils for raw materials and do not increase carbon dioxide
by combustion thereof have been gathering great attention. Even in
the field of polymers, biomass plastics produced from biomass
resources have been ardently developed.
[0004] A representative examples of the biomass plastics is
polylactic acids, and use thereof has been increasingly expanded to
dishes, packaging materials, miscellaneous goods and the like,
because they have relatively high heat resistance and mechanical
properties among the biomass plastics. In addition, the polylactic
acids have also been studied for a possibility as industrial
materials.
[0005] However, the properties of the polylactic acids such as
mechanical properties and heat resistance are unsatisfactory in
order for the polylactic acids to be used as industrial materials
in fields in which thermoplastic resins are used. Further, the
polylactic acids have a problem that they show significantly low
hydrolysis resistance when used under wet and hot conditions
because they have biodegradability.
[0006] Further, the polylactic acids have optical isomers, and it
is known that when a poly-L-lactic acid that is a polymer of
L-lactic acid and a poly-D-lactic acid that is a polymer of
D-lactic acid are mixed together, they form stereocomplex crystals
which are a material showing a higher melting point than crystals
of the poly-L-lactic acid alone or the poly-D-lactic acid alone
(see, Patent Document 1, Nonpatent Document 1). An attempt to apply
this stereocomplex polylactic acid to industrial applications such
as automobile parts and household appliance parts by taking
advantage of its heat resistance has been made (see, Patent
document 2).
[0007] However, when this stereocomplex polylactic acid is produced
by an industrially advantageous melt-extrusion process, it is very
difficult to achieve stereo-complexification to a sufficient level.
When stereo-complexification is insufficient, the stereocomplex
polylactic acid cannot exhibit good heat resistance that is a
characteristic thereof. Further, although the stereocomplex
polylactic acid has a tendency of showing a higher crystallization
rate than the poly-L-lactic acid or poly-D-lactic acid, it is still
insufficient to produce the stereocomplex polylactic acid
efficiently by injection molding. As described above, even the
stereocomplexpolylactic acid still has a number of problems in
order to be used in wide applications.
[0008] Under the circumstances, an attempt to replace some of
plastics which rely on oils for raw materials by biomass plastics
has recently been becoming popular as a measure for reducing
environmental burdens of the plastics, and as to thermoplastic
resins, it has been proposed to incorporate natural polymers such
as corn starch into the resins (see, Patent document 3). Further,
compositions comprising thermoplastic resins and polylactic acids
have been proposed (see, Patent documents 4 to 6).
[0009] As for polylactic acids, attempts to use them as industrial
materials by introducing resins such as aromatic polycarbonates and
a flame retardant into the polylactic acids have been made (see,
Patent document 7)
[0010] However, it is the current situation that a problem of
decrease of hydrolysis resistance that is derived from a
characteristic of the polylactic acids has not yet been solved and
hinders the above materials from being used as industrial materials
in various fields.
(Patent document 1) Japanese Patent Laid-Open Publication No.
63-241024 (Patent document 2) Japanese Patent No. 3583097 (Patent
document 3) Japanese Patent Laid-Open Re-Publication No. 7-506863
(Patent document 4) Japanese Patent No. 3279768 (Patent document 5)
Japanese Patent Laid-Open Publication No. 2005-48066 (Patent
document 6) Japanese Patent Laid-Open Publication No. 2005-48067
(Patent document 7) Japanese Patent Laid-Open Publication No.
2004-190026 (Nonpatent document 1) Macromolecules, 24, 5651
(1991)
DISCLOSURE OF THE INVENTION
First Aspect
[0011] An object of the present invention is to provide a resin
composition and a molded article that use a biomass-derived
polylactic acid and cause small burdens on the environment. Another
object of the present invention is to provide a resin composition
which comprises a thermoplastic resin (component A) and a
polylactic acid (component B) and has excellent hydrolysis
resistance. Still another object of the present invention is to
provide a resin composition having excellent heat resistance and
chemical resistance. Still another object of the present invention
is to provide a molded article having excellent heat resistance,
mechanical properties, hydrolysis resistance and chemical
resistance.
[0012] The present inventors have found that a molded article
having excellent heat resistance, mechanical properties, hydrolysis
resistance and chemical resistance is obtained by molding a resin
composition that comprises a thermoplastic resin (component A) and
a polylactic acid having a high stereocomplex crystal content, the
polylactic acid being obtained by melt-kneading a polylactic acid
containing at least 90% of L-lactic acid unit and a polylactic acid
containing at least 90% of D-lactic acid unit at high temperatures,
and have completed the present invention based on this finding.
[0013] That is, the present invention relates to a resin
composition comprising 100 parts by weight of thermoplastic resin
(component A) and 1 to 200 parts by weight of polylactic acid
(component B), wherein (i) the component B comprises a polylactic
acid (component B-1) that comprises 90 to 100 mol % of L-lactic
acid unit and 0 to 10 mol % of D-lactic acid unit and/or units
other than lactic acid and a polylactic acid (component B-4) that
comprises 90 to 100 mol % of D-lactic acid unit and 0 to 10 mol %
of L-lactic acid unit and/or units other than lactic acid, (ii) the
weight ratio (component B-1/component B-4) of the component B-1 to
component B-4 in the component B is within a range of 10/90 to
90/10, and (iii) the component B in the resin composition shows a
proportion of melt peaks at 195.degree. C. or higher to all melt
peaks in a temperature rising process in measurement by a
differential scanning calorimeter (DSC) of at least 20%.
[0014] Further, the present invention relates to a method for
producing a resin composition by melt-kneading 100 parts by weight
of thermoplastic resin (component A) and 1 to 200 parts by weight
of polylactic acid (component B), wherein
(i) the component B comprises a polylactic acid (component B-1)
that comprises 90 to 100 mol % of L-lactic acid unit and 0 to 10
mol % of D-lactic acid unit and/or units other than lactic acid and
a polylactic acid (component B-4) that comprises 90 to 100 mol % of
D-lactic acid unit and 0 to 10 mol % of L-lactic acid unit and/or
units other than lactic acid, (ii) the weight ratio (component
B-1/component B-4) of the component B-1 to component B-4 in the
component B is within a range of 10/90 to 90/10, and (iii) the
component B shows a proportion of melt peaks at 195.degree. C. or
higher to all melt peaks in a temperature rising process in
measurement by a differential scanning calorimeter (DSC) of at
least 20%.
(Second Aspect)
[0015] An object of the present invention is to provide a resin
composition and a molded article that use a biomass-derived
polylactic acid and cause small burdens on the environment. Another
object of the present invention is to provide a resin composition
comprising a polylactic acid (component B) and having excellent
hydrolysis resistance. Still another object of the present
invention is to provide a resin composition having excellent heat
resistance and chemical resistance. Still another object of the
present invention is to provide a molded article having excellent
heat resistance, mechanical properties, hydrolysis resistance and
chemical resistance.
[0016] The present inventors have found that a molded article
having excellent heat resistance, mechanical properties, hydrolysis
resistance and chemical resistance is obtained by molding a resin
composition that comprises a polylactic acid (component B) having a
high stereocomplex crystal content, the polylactic acid being
obtained by melt-kneading a polylactic acid containing at least 90%
of L-lactic acid unit and a polylactic acid containing at least 90%
of D-lactic acid unit at high temperatures, and have completed the
present invention based on this finding.
[0017] That is, the present invention relates to a molded article
comprising a polylactic acid (component B) that shows a proportion
of melt peaks at 195.degree. C. or higher to all melt peaks in a
temperature rising process in measurement by a differential
scanning calorimeter (DSC) of at least 20%.
[0018] Further, the present invention relates to a method for
producing a molded article by molding pellets comprising a
polylactic acid (component B) that shows a proportion of melt peaks
at 195.degree. C. or higher to all melt peaks in a temperature
rising process in measurement by a differential scanning
calorimeter (DSC) of at least 70%.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] FIG. 1 is a perspective view of a jig for carrying out
three-point bending that is used in a chemical resistance test 2
(automobile part).
(Explanations of Letters or Notations in FIG. 1)
[0020] 1: First fixed bar (3.9 mm.phi., (made of) stainless steel)
[0021] 2: Center portion of the test piece [0022] (set on a top of
the test piece which forms an arc) [0023] 3: Movable bar for
distorted load [0024] (3.9 mm.phi., (made of) stainless steel)
[0025] 4: Screw for distored load [0026] (reaching a rear side of
pedestal 7, turn a screw from the position where contacted with
non-load test piece, and load pre-determined distortion to the test
piece based on screw-pitch) [0027] 5: Test piece [0028] 6: Second
fixed bar (3.9 mm.phi., stainless steel) [0029] 7: Pedestal [0030]
8: Horizontal distance (50.0 mm) between a second fixed bar and a
movable bar for distored load [0031] 9: Horizontal distance (50.0
mm) between a first fixed bar and a movable bar for distored
load
[0032] FIG. 2 is a perspective view of the front side of the
housing of a notebook-size personal computer used in a chemical
resistance test 4 (length: 178 mm, width: 245 mm, edge height: 10
mm, thickness: 1.2 mm).
[0033] FIG. 3 is a front view of the front side of the housing of
the notebook-size personal computer, with gate positions and a
position from which a test piece for evaluation is cut.
[0034] FIG. 4 is a front view of the back side of the housing of
the notebook-size personal computer, with ribbed bosses (matte
surface parts have bosses having ribs on the upper and lower
sides).
(Explanations of letters or notations in FIGS. 2 to 4) [0035] 1:
Notebook-size personal computer housing [0036] 2: Frosted surface
side [0037] 3: Mirror side [0038] 4: Gate (five pin-gates, 0.8
mm.phi.) [0039] 5: Collecting test pieces portion for measurement
of proportion (R.sub.195 or higher) of melt peak of 195.degree. C.
or higher [0040] 6: Boss with rib (corresponding to rear side of
mirror) [0041] 7: boss with rib (corresponding to rear side of
frosted surface side)
[0042] FIG. 5 is a perspective view of the front side of an OA
equipment exterior part used in a chemical resistance test 5
(dimension: length=500 mm, width=600 mm, thickness: 2.5 mm).
(Explanations of Letters or Notations in FIG. 5)
[0043] 1: Office Automation equipment exterior part [0044] 2:
Pin-side gate (width of side-gate of 5 mm, thickness of 1.2 mm,
gate bend length of 6 mm; side gate tab of width of 8
mm.times.length of 15 mm; diameter of pin-gate to tab portion of
1.8 mm) [0045] 3: Collecting test pieces portion for measurement of
proportion (R.sub.195 or higher) of melt peak of 195.degree. C. or
higher
[0046] FIG. 6 is an example of a vertical section of an optical
disk.
[0047] FIG. 7 is an example of a vertical section of an optical
disk.
[0048] FIG. 8 is an example of a vertical section of an optical
disk.
[0049] FIG. 9 is an example of a vertical section of an optical
disk.
(Explanations of letters or notations in FIGS. 6 to 9) [0050] 1:
Substrate [0051] 2: Reflexing layer [0052] 3: Recording layer
[0053] 4: Light-permeative layer [0054] 5: First reflexing layer
[0055] 6: First recording layer [0056] 7: Medium layer [0057] 8:
Second reflexing layer [0058] 9: Second recording layer [0059] 10:
Reflexing film [0060] 11: First dielectric layer [0061] 12:
Phase-changing type recording layer [0062] 13: Second dielectric
layer [0063] 14: Light-permeative layer
BEST MODE FOR CARRYING OUT THE INVENTION
First Embodiment
[Resin Composition]
[0064] A resin composition of the present invention is a resin
composition comprising 100 parts by weight of thermoplastic resin
(component A) and 1 to 200 parts by weight of polylactic acid
(component B).
<Thermoplastic Resin: Component A>
[0065] The thermoplastic resin (component A) is preferably a
polycarbonate resin, polyester resin, polyolefin resin or styrene
resin. These may be used alone or in combination of two or
more.
(Aromatic Polycarbonate Resin)
[0066] An aromatic polycarbonate resin (hereinafter may be simply
referred to as "polycarbonate") is obtained by reacting a dihydric
phenol with a carbonate precursor. Illustrative examples of the
reaction method include interfacial polycondensation, melt
transesterification, solid-phase transesterification of carbonate
prepolymer, and ring-opening polymerization of cyclic carbonate
compound. The component A is preferably the aromatic polycarbonate
resin, particularly preferably a bisphenol-A-based aromatic
polycarbonate resin.
[0067] Specific examples of the dihydric phenol include
hydroquinone, resorcinol, 4,4'-biphenol,
1,1-bis(4-hydroxyphenyl)ethane, 2,2-bis(4-hydroxyphenyl)propane
(commonly known as "bisphenol A"),
2,2-bis(4-hydroxy-3-methylphenyl)propane,
2,2-bis(4-hydroxyphenyl)butane,
1,1-bis(4-hydroxyphenyl)-1-phenylethane,
1,1-bis(4-hydroxyphenyl)cyclohexane,
1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane,
2,2-bis(4-hydroxyphenyl)pentane,
4,4'-(p-phenylenediisopropylidene)diphenol,
4,4'-(m-phenylenediisopropylidene)diphenol,
1,1-bis(4-hydroxyphenyl)-4-isopropylcyclohexane,
bis(4-hydroxyphenyl)oxide, bis(4-hydroxyphenyl)sulfide,
bis(4-hydroxyphenyl)sulfoxide, bis(4-hydroxyphenyl)sulfone,
bis(4-hydroxyphenyl)ketone, bis(4-hydroxyphenyl)ester,
2,2-bis(3,5-dibromo-4-hydroxyphenyl)propane,
bis(3,5-dibromo-4-hydroxyphenyl)sulfone,
bis(4-hydroxy-3-methylphenyl)sulfide,
9,9-bis(4-hydroxyphenyl)fluorene, and
9,9-bis(4-hydroxy-3-methylphenyl)fluorene. Of these,
bis(4-hydroxyphenyl)alkane, particularly bisphenol A (hereinafter
may be abbreviated as "BPA"), is widely used.
[0068] In the present invention, in addition to the
bisphenol-A-based polycarbonate which is a widely used
polycarbonate, a special polycarbonate produced by using other
dihydric phenol can also be used as the component A.
[0069] For example, a polycarbonate (homopolymer or copolymer)
using, as apart or all of the dihydric phenol component,
4,4'-(m-phenylenediisopropylidene)diphenol (hereinafter may be
abbreviated as "BPM"), 1,1-bis(4-hydroxyphenyl)cyclohexane,
1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane (hereinafter
may be abbreviated as "Bis-TMC"), 9,9-bis(4-hydroxyphenyl)fluorene
and 9,9-bis(4-hydroxy-3-methylphenyl)fluorene (hereinafter may be
abbreviated as "BCF"), is suited for applications in which
requirements for a dimensional change caused by water absorption
and morphological stability are particularly stringent. These
dihydric phenols other than BPA are preferably used in an amount of
5 mol % or larger, particularly preferably 10 mol % or larger, of
the whole dihydric phenol component constituting the
polycarbonate.
[0070] In particular, when high rigidity and better hydrolysis
resistance are required, it is particularly suitable that the
component A which constitutes the resin composition is any of the
following copolymerized polycarbonates (1) to (3).
(1) copolymerized polycarbonate in which BPM accounts for 20 to 80
mol % (more suitably 40 to 75 mol %, much more suitably 45 to 65
mol %) and BCF accounts for 20 to 80 mol % (more suitably 25 to 60
mol %, much more suitably 35 to 55 mol %) out of 100 mol % of the
dihydric phenol component constituting the polycarbonate. (2)
copolymerized polycarbonate in which BPA accounts for 10 to 95 mol
% (more suitably 50 to 90 mol %, much more suitably 60 to 85 mol %)
and BCF accounts for 5 to 90 mol % (more suitably 10 to 50 mol %,
much more suitably to 40 mol %) out of 100 mol % of the dihydric
phenol component constituting the polycarbonate. (3) copolymerized
polycarbonate in which BPM accounts for 20 to 80 mol % (more
suitably 40 to 75 mol %, much more suitably 45 to 65 mol %) and
Bis-TMC accounts for to 80 mol % (more suitably 25 to 60 mol %,
much more suitably 35 to 55 mol %) out of 100 mol % of the dihydric
phenol component constituting the polycarbonate.
[0071] These special polycarbonates may be used alone or in
admixture of two or more as appropriate. Further, these may be used
as a mixture with the widely used bisphenol A based
polycarbonate.
[0072] Production methods and characteristics of these special
polycarbonates are described in detail in, for example, Japanese
Patent Laid-Open Publication Nos. 6-172508, 8-27370, 2001-55435 and
2002-117580.
[0073] Of the above various polycarbonates, polycarbonates having a
water absorption percentage and Tg (glass transition temperature)
within the following ranges as a result of adjustment of
copolymerization composition and the like are particularly suitable
in fields in which morphological stability is required, because the
polymers have good hydrolysis resistance and undergo exceptionally
small warpage after molding.
(i) polycarbonate having a water absorption percentage of 0.05 to
0.15 wt %, preferably 0.06 to 0.13 wt %, and a Tg of 120 to
180.degree. C., or (ii) polycarbonate having a Tg of 160 to
250.degree. C., preferably 170 to 230.degree. C., and a water
absorption percentage of 0.10 to 0.30 wt %, preferably 0.13 to 0.30
wt %, more preferably 0.14 to 0.27 wt %.
[0074] The water absorption percentage of the polycarbonate is a
value obtained by measuring the moisture percentage of a
disk-shaped test piece having a diameter of 45 mm and a thickness
of 3.0 mm after immersing the test piece in water at 23.degree. C.
for 24 hours in accordance with IS062-1980. Further, Tg (glass
transition temperature) is a value obtained by differential
scanning calorimeter (DSC) measurement according to JIS K7121.
[0075] Meanwhile, as the carbonate precursor, carbonyl halide,
carbonate ester or haloformate is used. Specific examples thereof
include phosgene, diphenyl carbonate, and dihaloformate of dihydric
phenol.
[0076] When the polycarbonate is produced from the above dihydric
phenol and carbonate precursor by interfacial polymerization, a
catalyst, a terminal blocking agent, an antioxidant for preventing
oxidation of the dihydric phenol, and the like may be used as
required. Further, the polycarbonate may be a branched
polycarbonate copolymerized with a polyfunctional aromatic compound
having three or more functional groups. Illustrative examples of
the polyfunctional aromatic compound having three or more
functional groups include 1,1,1-tris(4-hydroxyphenyl)ethane and
1,1,1-tris(3,5-dimethyl-4-hydroxyphenyl)ethane.
[0077] When the polyfunctional compound that produces the branched
polycarbonate is contained, the amount thereof is 0.001 to 1 mol %,
preferably 0.005 to 0.9 mol %, particularly preferably 0.01 to 0.8
mol %, based on the total amount of the polycarbonate. Further, in
the case of melt transesterification in particular, a branched
structure may be produced as a side reaction, and the amount of the
branched structure is 0.001 to 1 mol %, preferably 0.005 to 0.9 mol
%, particularly preferably 0.01 to 0.8 mol %, based on the total
amount of the polycarbonate. The amount of the branched structure
can be calculated by 1H-NMR measurement.
[0078] Further, the aromatic polycarbonate resin as the component A
in the resin composition of the present invention may be a
polyester carbonate copolymerized with an aromatic or aliphatic
(including alicyclic) difunctional carboxylic acid, a copolymerized
polycarbonate copolymerized with a difunctional alcohol (including
alicyclic), or a polyester carbonate copolymerized with the
difunctional carboxylic acid and the difunctional alcohol. Further,
the aromatic polycarbonate resin may be a mixture of two or more of
polycarbonates obtained.
[0079] The above aliphatic difunctional carboxylic acid is
preferably .alpha.,.omega.-dicarboxylic acid. Preferred examples of
the aliphatic difunctional carboxylic acid include linear saturated
aliphatic dicarboxylic acids such as sebacic acid (decanedioic
acid), dodecanedioic acid, tetradecanedioic acid, octadecanedioic
acid and icosanedioic acid, and alicyclic dicarboxylic acids such
as cyclohexane dicarboxylic acid. As the difunctional alcohol, an
alicyclic diol is more suitable. Illustrative examples thereof
include cyclohexane dimethanol, cyclohexane diol, and
tricyclodecane dimethanol.
[0080] Further, in the present invention, as the component A, a
polycarbonate-polyorganosiloxane copolymer copolymerized with a
polyorganosiloxane unit can also be used.
[0081] The aromatic polycarbonate resin as the component A may be a
mixture of two or more of various polycarbonates such as the above
polycarbonates comprising different dihydric phenols,
polycarbonates containing branch components, polyester carbonates
and polycarbonate-polyorganosiloxane copolymer. Further, a mixture
of two or more of polycarbonates produced by different methods,
polycarbonates using different terminal blocking agents and the
like can also be used.
[0082] Reaction methods such as interfacial polymerization, melt
transesterification, solid-phase transesterification of carbonate
prepolymer and ring-opening polymerization of cyclic carbonate
compound which are production methods of the polycarbonate are
methods which are well known by various literatures and patent
publications.
[0083] The viscosity average molecular weight of the aromatic
polycarbonate resin as the component A is not limited. However,
when the viscosity average molecular weight is lower than 10,000,
strength and the like deteriorate, while when it is higher than
50,000, moldability deteriorates. Thus, the viscosity average
molecular weight is preferably 10,000 to 50,000, more preferably
12,000 to 30,000, much more preferably 14,000 to 28,000. In this
case, it is also possible to mix a polycarbonate whose viscosity
average molecular weight is out of the above range as long as
moldability and the like are retained. For example, a
high-molecular-weight polycarbonate component whose viscosity
average molecular weight is higher than 50,000 may be mixed in.
[0084] The viscosity average molecular weight in the present
invention is determined in the following manner. First, specific
viscosity (.eta..sub.sp) calculated by the following formula:
Specific Viscosity (.eta..sub.sp)=(t-t.sub.0)/t.sub.0
[t.sub.0 is the number of seconds for dropping methylene chloride,
t is the number of seconds for dropping sample solution], is
determined from a solution prepared by dissolving 0.7 g of aromatic
polycarbonate in 100 ml of methylene chloride at 20.degree. C. by
using an Ostwald viscometer.
[0085] Viscosity average molecular weight (M) is calculated from
the determined specific viscosity (.eta..sub.sp) by the following
formula:
.eta..sub.sp/c=[.eta.]+0.45.times.[.eta.].sup.2c([.eta.] is
limiting viscosity.)
[.eta.]=1.23.times.10.sup.-4M.sup.0.83
c=0.7
[0086] The viscosity average molecular weight in the resin
composition of the present invention is measured in the following
manner. That is, the resin composition is dissolved in methylene
chloride whose weight is 20 to 30 times the weight of the resin
composition, and a soluble part is collected by sellite filtration.
Then, the solution is removed from the soluble part which is then
fully dried to obtain a solid of the methylene chloride soluble
part. Specific viscosity (.eta..sub.sp) at 20.degree. C. is
determined from a solution prepared by dissolving 0.7 g of the
solid in 100 ml of methylene chloride by using an Ostwald
viscometer, and its viscosity average molecular weight M is
calculated by the above formula.
[0087] As the aromatic polycarbonate resin which is the component
A, recycled aromatic polycarbonate resins can also be used. In that
case, the proportion of low environmental burden components
including the component B which is a substitute material for oil
resource material increases, and the resin composition becomes a
more preferred material in terms of environmental burden reducing
effect. The recycled aromatic polycarbonate resin is a resin
recovered at least from a resin molded article formed by a
processing step for producing a target product without going
through a decomposition step of the polymer. Illustrative examples
thereof include resin molded articles separated and recovered from
used products, resin molded articles separated and recovered from
defective products, and resin molded articles comprising unwanted
parts such as spurs and runners produced at the time of molding.
The decomposition step refers to a step intended to decompose bonds
that form the main chain of the aromatic polycarbonate and collect
monomers and oligomers that result from the decomposition and does
not refer to thermal decomposition in steps intended for kneading,
crushing and processing.
[0088] A recycled aromatic polycarbonate that comprises preferably
at least 90 wt %, more preferably at least 95 wt %, much more
preferably at least 98 wt % of aromatic polycarbonate component out
of 100 wt % of resin material is used.
[0089] Preferred examples of the used products include various
glazing materials typified by soundproof walls, glass windows,
translucent roof materials and automobile sliding roofs,
transparent members such as windshields and automobile headlamp
lenses, containers such as water bottles, and optical recording
media. These do not contain large amounts of additives or other
resins, and a target quality is obtained easily and stably. In
particular, a molded article comprising a hard coating laminated on
the surface of a transparent polycarbonate molded article is
exemplified as a preferred aspect. The reason is that the molded
article is often colored by the influence of hard coating agent
while having good transparency. Specific examples of the molded
article include various glazing materials and transparent members
such as windshields and automobile headlamps.
[0090] Further, as the recycled aromatic polycarbonate resin,
crushed pieces of unwanted resin molded article and pellets
produced by melt-extruding the crushed pieces again can be used.
Further, when the resin molded article has a printed coating film,
sticker, label, decorative coating film or conductive coating film
or has been subjected to conductive plating, metal deposition or
the like, crushed pieces having the covered portion removed (the
resin molded article may be crushed after removal of the covered
portion or the covered portion may be removed after crushing of the
resin molded article) and pellets produced by melt-extruding the
crushed pieces can be used. When the printed coating film or the
like is included, the effect of the present invention is not
exerted sufficiently with ease because the crushed pieces or
pellets are liable to be colored by the influence of the printed
coating film or the like. Accordingly, it is preferable to remove
the printed coating film or the like. Illustrative examples of a
method of removing the printed coating film, plating or the like
include a method of extending the resin molded article under
pressure between two rolls, a method of bringing the resin molded
article into contact with heated/pressurized water, various
solvents, an acid/alkaline aqueous solution or the like, a method
of mechanically scraping the portion to be removed, a method of
irradiating the resin molded article with ultrasound, and a method
of subjecting the resin molded article to a blast treatment. It is
also possible to use these methods in combination.
[0091] Meanwhile, in the case of a molded article comprising a hard
coating laminated on the surface of a transparent polycarbonate
molded article, it is more efficient and leads to a reduction in
environmental burdens to add crushed pieces as they are because
good color can be attained. The crushed pieces can be produced by
crushing the molded article by use of a known crusher.
[0092] The content of the recycled aromatic polycarbonate resin is
preferably at least 5 wt %, more preferably at least 10 wt %, much
more preferably at least 15 wt %, out of 100 wt % of the aromatic
polycarbonate resin which is the component A. Although the upper
limit may be set at 100 wt %, it is preferably 50 wt % or lower
from a practical standpoint because a resin composition having
stable properties is obtained.
(Polyester Resin)
[0093] A polyester resin used in the present invention is a polymer
or copolymer obtained by polycondensation of a dicarboxylic acid or
ester forming derivative thereof with a diol or polycondensation of
a hydroxycarboxylic acid or ester forming derivative thereof and is
thermoplastic polyester resins other than polylactic acids.
[0094] Illustrative examples of the dicarboxylic acid or ester
forming derivative thereof include aromatic dicarboxylic acids such
as terephthalic acid, isophthalic acid, orthophthalic acid,
5-sodium sulfoisophthalate, 2,6-naphthalene dicarboxylic acid,
2,7-naphthalene dicarboxylic acid, 4,4'-biphenyl dicarboxylic acid,
bis(p-carboxyphenyl)methane, 4,4'-stilbene carboxylic acid,
4,4'-diphenyl ether dicarboxylic acid, anthracene dicarboxylic acid
and ethylene-bis-p-benzoic acid; aliphatic dicarboxylic acids such
as oxalic acid, succinic acid, adipic acid, sebacic acid, azelaic
acid, dodecanedioic acid, malonic acid and glutaric acid; and
alicyclic dicarboxylic acids such as 1,4-cyclohexane dicarboxylic
acid and dimethyl esters thereof. These dicarboxylic acids can be
used alone or in admixture of two or more. Of these, terephthalic
acid and 2,6-naphthalene dicarboxylic acid and dimethyl esters
thereof can be preferably used.
[0095] Illustrative examples of the diol include aliphatic diols
such as ethylene glycol, propylene glycol, 1,3-propanediol,
1,4-butanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol
and decamethylene glycol; alicyclic diols such as 1,4-cyclohexane
dimethanol and 1,3-cyclohexane dimethanol; and dihydric phenols
such as p-xylenediol and bisphenol A. Further, one or more
long-chain diols having a molecular weight of 400 to 6,000 such as
polyethylene glycol, poly-1,3-propylene glycol and
polytetramethylene glycol may be copolymerized. These diol
components can be used alone or in admixture of two or more. Of
these, ethylene glycol, 1,3-propanediol and 1,4-butanediol can be
preferably used.
[0096] Further, illustrative examples of the hydroxycarboxylic acid
include aliphatic hydroxycarboxylic acids such as glycolic acid,
hydroxypropionic acid, hydroxybutyric acid, hydroxyvaleric acid and
hydroxycaproic acid, and ester forming derivatives thereof; and
aromatic hydroxycarboxylic acids such as p-hydroxybenzoic acid and
6-hydroxy-2-naphthoic acid, and ester forming derivatives thereof.
Further, condensed cyclic esters of aliphatic hydroxycarboxylic
acids such as glycolade and caprolactone can also be used. These
hydroxycarboxylic acid components can be used alone or in admixture
of two or more.
[0097] Specific examples of polymers or copolymers comprising
combinations of these monomers include aromatic polyesters such as
polyethylene terephthalate, polyethylene
(terephthalate/isophthalate), polypropylene terephthalate,
polypropylene (terephthalate/isophthalate), polybutylene
terephthalate, polybutylene (terephthalate/isophthalate),
polyethylene naphthalate, polypropylene naphthalate, polybutylene
naphthalate, polyethylene (terephthalate/succinate), polyethylene
(terephthalate/adipate), polyethylene (terephthalate/sebacate),
polypropylene (terephthalate/succinate), polypropylene
(terephthalate/adipate), polypropylene (terephthalate/sebacate),
polybutylene (terephthalate/succinate), polybutylene
(terephthalate/adipate), polybutylene (terephthalate/sebacate), and
cyclohexane dimethanol copolymerized polyethylene terephthalate;
aliphatic polyesters such as polyethylene oxalate, polypropylene
oxalate, polybutylene oxalate, polyneopentyl glycol oxalate,
polyethylene succinate, polypropylene succinate, polybutylene
succinate, polybutylene adipate, polypropylene adipate,
polyethylene adipate, polybutylene (succinate/adipate),
polypropylene (succinate/adipate), polyethylene
(succinate/adipate), polyhydroxyalkanoate, polycaprolactone, and
polyglycolic acid; aliphatic polyester carbonates such as
polybutylene succinate-carbonate; and liquid crystalline polyesters
such as p-oxybenzoic acid/polyethylene terephthalate and
p-oxybenzoic acid/6-oxy-2-naphthoic acid.
[0098] Of these, particularly preferred polyester resins are
polyethylene terephthalate, polypropylene terephthalate,
polybutylene terephthalate, cyclohexane dimethanol copolymerized
polyethylene terephthalate, polyethylene naphthalate, polybutylene
naphthalate, and the like.
[0099] The aromatic polyester is produced by polymerizing a
dicarboxylic acid or ester forming derivative thereof with a diol
or ester forming derivative thereof under heating in the presence
of a polycondensation catalyst containing titanium, germanium,
antimony or the like in accordance with a conventional procedure
and discharging by-produced water or lower alcohol out of the
system.
[0100] Illustrative examples of a germanium-containing
polymerization catalyst include an oxide, hydroxide, halide,
alcoholate and phenolate of germanium. Specific examples thereof
include germanium oxide, germanium hydroxide, germanium
tetrachloride, and tetramethoxygermanium. Preferred specific
examples of an organotitanium compound that is a
titanium-containing polymerization catalyst include titanium
tetrabutoxide, titanium isopropoxide, titanium oxalate, titanium
acetate, titanium benzoate, titanium trimellitate, and a reaction
product of tetrabutyl titanate and trimellitic anhydride. The
organotitanium compound is preferably used in such an amount that
its titanium atom is 3 to 12 mg atomic percentage based on the acid
component constituting the aromatic polyester.
[0101] Further, it is possible to use a compound of manganese,
zinc, calcium, magnesium or the like that is used in a
transesterification reaction which is a preliminary step for
conventionally known polycondensation in combination with the above
catalyst, and it is also possible to carry out polycondensation
after deactivating the catalyst by a compound of phosphoric acid or
phosphorous acid after completion of the transesterification
reaction. The aromatic polyester can be produced by either of a
batch method and a continuous polymerization method. Further, an
aromatic polyester obtained may contain various stabilizers and
modifiers.
(Styrene Resin)
[0102] Illustrative examples of a styrene resin used in the present
invention include styrene hard resins composed essentially of
aromatic vinyl compounds, and styrene rubbery resins comprising
rubbery polymers.
[0103] The styrene hard resin in the present invention refers to a
polymer or copolymer of aromatic vinyl compounds and a polymer
obtained by copolymerizing the aromatic vinyl compounds with other
vinyl monomers that can be copolymerized with the aromatic vinyl
compounds. The styrene hard resin has a glass transition
temperature of at least 40.degree. C. in the case of an amorphous
resin and has a melting point of at least 40.degree. C. in the case
of a crystalline resin. These glass transition temperature and
melting point can be determined by differential scanning
calorimeter (DSC) measurement according to JIS K7121.
[0104] Illustrative examples of the above aromatic vinyl compound
include styrene, .alpha.-methylstyrene, o-methylstyrene,
p-methylstyrene, vinylxylene, ethylstyrene, dimethylstyrene,
p-t-butylstyrene, vinylnaphthalene, methoxystyrene,
monobromstyrene, dibromstyrene, fluorostyrene, and tribromstyrene.
Styrene is particularly preferred.
[0105] Preferred examples of the other vinyl monomers that can be
copolymerized with the above aromatic vinyl compounds include vinyl
cyanide compounds and (meth) acrylic ester compounds. Illustrative
examples of the vinyl cyanide compounds include acrylonitrile and
methacrylonitrile, and acrylonitrile is particularly preferred.
Illustrative examples of the (meth)acrylic ester compounds include
methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate,
isopropyl (meth)acrylate, butyl (meth)acrylate, amyl
(meth)acrylate, hexyl (meth)acrylate, octyl (meth)acrylate,
2-ethylhexyl (meth)acrylate, cyclohexyl (meth)acrylate, dodecyl
(meth)acrylate, octadecyl (meth)acrylate, phenyl (meth)acrylate,
and benzyl (meth)acrylate. The expression "(meth)acrylate" includes
both methacrylate and acrylate, and the expression "(meth) acrylic
ester" includes both methacrylic ester and acrylic ester. A
particularly suitable (meth)acrylic ester compound is methyl
methacrylate.
[0106] Further, illustrative examples of the other vinyl monomers
that can be copolymerized with the aromatic vinyl compounds other
than the vinyl cyanide compounds and the (meth)acrylic ester
compounds include epoxy-group-containing methacrylic esters such as
glycidyl methacrylate; maleimide monomers such as maleimide,
N-methyl maleimide and N-phenyl maleimide; and
.alpha.,.beta.-unsaturated carboxylic acids and anhydrides thereof
such as acrylic acid, methacrylic acid, maleic acid, maleic
anhydride, phthalic acid, and itaconic acid.
[0107] Illustrative examples of suitable styrene hard resins
include a polystyrene, MS copolymer, AS copolymer, MAS copolymer
and SMA copolymer. The MS copolymer is a copolymer composed
essentially of methyl methacrylate and styrene. The AS copolymer is
a copolymer composed essentially of acrylonitrile and styrene. The
MAS copolymer is a copolymer composed essentially of methyl
methacrylate, acrylonitrile and styrene. The SMA copolymer is a
copolymer composed essentially of styrene and maleic anhydride
(MA). Of these, the AS copolymer is particularly preferred.
[0108] The AS copolymer may be produced by any of bulk
polymerization, solution polymerization, suspension polymerization
and emulsion polymerization methods, but it is preferably produced
by the bulk polymerization or suspension polymerization method. The
AS copolymer is most preferably produced by the bulk polymerization
method, and the polymerization method is the most common in the
industry. Further, the copolymerization method may be single-step
copolymerization or multistep copolymerization. The weight average
molecular weight of the AS copolymer is 40,000 to 200,000 in terms
of standard polystyrene by GPC measurement. While its lower limit
is more preferably 50,000, much more preferably 70,000, its upper
limit is more preferably 160,000, much more preferably 150,000.
[0109] The styrene rubbery resin refers to a polymer comprising a
rubber component having a glass transition temperature of
10.degree. C. or lower, preferably -10.degree. C. or lower, more
preferably -30.degree. C. or lower, and a copolymer comprising the
polymer comprising the rubber component and other polymer chain
bonded to the polymer. It also refers to a polymer containing the
rubber component in an amount of at least 35 wt %, more preferably
45 wt %, based on 100 wt % of the rubbery polymer. An appropriate
upper limit of the content of the rubber component is around 90 wt
% from a practical standpoint.
[0110] The styrene rubbery resin in the present invention is more
suitably a copolymer having other polymer chain bonded thereto. It
is widely known that in production of a rubbery polymer comprising
a rubber component to which other polymer chain is grafted, a
polymer or copolymer which is not grafted to the rubber component
exists in no small amount. The styrene rubbery resin in the present
invention may contain such a free polymer or copolymer.
[0111] Illustrative examples of the styrene rubbery resin in the
present invention include an SB (styrene-butadiene) copolymer, ABS
(acrylonitrile-butadiene-styrene) copolymer, MBS (methyl
methacrylate-butadiene-styrene) copolymer, MABS (methyl
methacrylate-acrylonitrile-butadiene-styrene) copolymer, MB (methyl
methacrylate-butadiene) copolymer, ASA
(acrylonitrile-styrene-acrylic rubber) copolymer, AES
(acrylonitrile-ethylene propylene rubber-styrene) copolymer, MA
(methyl methacrylate-acrylic rubber) copolymer, MAS (methyl
methacrylate-acrylic rubber-styrene) copolymer, methyl
methacrylate-acryl.cndot.butadiene rubber copolymer, methyl
methacrylate-acryl.cndot.butadiene rubber-styrene copolymer, and
methyl methacrylate-(acryl.cndot.silicone IPN rubber) copolymer.
These copolymers are preferably core-shell-type graft copolymers in
which polymer chains comprising the above monomers are bonded to a
polymer comprising a rubber component as a core.
[0112] Of these, the acrylonitrile-butadiene-styrene copolymer (ABS
copolymer) is particularly preferred. The ABS copolymer in the
present invention preferably has a rubber particle diameter of 0.1
to 5.0 .mu.m, more preferably 0.2 to 3.0 .mu.m, particularly
preferably 0.2 to 1.5 .mu.m. The ABS copolymer may have simple
rubber particle diameter distribution or rubber particle diameter
distribution having two or more uplifts. Further, as to its
morphology, the rubber particles may form a simple phase or may
have a salami structure by containing an occlusion phase around the
particles.
[0113] The weight ratio (graft ratio (wt %)) of the grafted vinyl
cyanide compound and aromatic vinyl compound to the diene rubber
component is preferably 10 to 100%, more preferably 15 to 70%, much
more preferably 15 to 40%.
[0114] The ABS copolymer may be produced by any of bulk
polymerization, suspension polymerization and emulsion
polymerization, but it is preferably produced by suspension
polymerization or bulk polymerization. Further, in the production
method, an AS copolymer that is not grafted to the diene rubber is
produced in no small amount. Therefore, the ABS copolymer is
generally produced as a mixture with the AS copolymer.
(Polyolefin Resin)
[0115] A polyolefin resin used in the present invention is a
polymer of one or more .alpha.-olefins such as ethylene, propylene,
1-butene, 3-methyl-1-butene, 1-pentene, 4-methyl-1-pentene,
1-hexene, and 5-methyl-1-hexene. Alternatively, a mixture of two or
more of these polymers can also be used.
[0116] The polyolefin resin in the present invention may be
copolymerized with other copolymerizable monomer components.
Illustrative examples of the copolymerizable components include
diene compounds, .alpha.,.beta.-unsaturated carboxylic acid
derivatives, styrene compounds, and vinyl acetate derivatives.
Specific examples of the copolymerizable components include acrylic
acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid,
crotonic acid, methyl maleic acid, methyl fumaric acid, mesaconic
acid, citraconic acid, glutaconic acid, methyl acrylate, ethyl
acrylate, butyl acrylate, 2-ethylhexyl acrylate, hydroxyethyl
acrylate, methyl methacrylate, 2-ethylhexyl methacrylate,
hydroxyethyl methacrylate, aminoethyl methacrylate, dimethyl
maleate, dimethyl itaconate, sodium methacrylate, potassium
methacrylate, magnesium methacrylate, zinc acrylate, maleic
anhydride, itaconic anhydride, citraconic anhydride, glycidyl
acrylate, and glycidyl methacrylate.
[0117] Specific examples of the polyolefin resin include a
polyethylene, polypropylene, ethylene-vinyl acetate copolymer,
ethylene-ethyl acrylate copolymer, ethylene-acrylic acid copolymer,
ethylene-methyl methacrylate copolymer, ethylene-.alpha.-olefin
copolymer, ethylene-propylene copolymer, and propylene-butene
copolymer. These may be used alone or in combination of two or
more.
<Polylactic Acid: Component B>
[0118] The polylactic acid (component B) comprises a polylactic
acid (component B-1) that comprises 90 to 100 mol % of L-lactic
acid unit and 0 to 10 mol % of D-lactic acid unit and/or units
other than lactic acid and a polylactic acid (component B-4) that
comprises 90 to 100 mol % of D-lactic acid unit and 0 to 10 mol %
of L-lactic acid unit and/or units other than lactic acid.
[0119] The component B-1 and the component B-4 are polylactic acids
comprising an L-lactic acid unit and D-lactic acid unit represented
by the following formula (i) as basic components.
##STR00001##
[0120] The weight average molecular weight of the polylactic acid
(component B) is preferably 100,000 to 500,000, more preferably
100,000 to 300,000. The weight average molecular weight is a weight
average molecular weight value in terms of standard polystyrene by
gel permeation chromatography (GPC) measurement using chloroform as
an eluent.
[0121] The component B comprises a component B-1, B-2 or B-3
composed essentially of the L-lactic acid unit and a component B-4,
B-5 or B-6 composed essentially of the D-lactic acid unit.
(Poly-L-Lactic Acid)
[0122] The component B-1 is a polylactic acid comprising 90 to 100
mol % of the L-lactic acid unit and 0 to 10 mol % of the D-lactic
acid unit and/or units other than lactic acid. The component B-2 is
a polylactic acid comprising 90 to 99 mol % of the L-lactic acid
unit and 1 to 10 mol % of the D-lactic acid unit and/or units other
than lactic acid. The component B-3 is a polylactic acid comprising
higher than 99 mol % to not higher than 100 mol % of the L-lactic
acid unit and 0 mol % or higher to lower than 1 mol % of the
D-lactic acid unit and/or units other than lactic acid. Therefore,
the component B-1 includes the component B-2 and the component B-3.
These may be referred to as "poly-L-lactic acid".
(Poly-D-Lactic Acid)
[0123] The component B-4 is a polylactic acid comprising 90 to 100
mol % of the D-lactic acid unit and 0 to 10 mol % of the L-lactic
acid unit and/or units other than lactic acid. The component B-5 is
a polylactic acid comprising 90 to 99 mol % of the D-lactic acid
unit and 1 to 10 mol % of the L-lactic acid unit and/or units other
than lactic acid. The component B-6 is a polylactic acid comprising
higher than 99 mol % to not higher than 100 mol % of the D-lactic
acid unit and 0 mol % or higher to lower than 1 mol % of the
L-lactic acid unit and/or units other than lactic acid. Therefore,
the component B-4 includes the component B-5 and the component B-6.
These may be referred to as "poly-D-lactic acid".
[0124] The polylactic acid (component B) preferably comprises a
specific combination of the poly-L-lactic acid and the
poly-D-lactic acid. That is, the polylactic acid (component B)
preferably comprises the component B-1 and the component B-4 in a
weight ratio (component B-1/component B-4) of 10/90 to 90/10.
[0125] The polylactic acid (component B):
(1) preferably comprises the component B-1 and the component B-5 in
a weight ratio (component B-1/component B-5) of 10/90 to 90/10, or
(2) preferably comprises the component B-4 and the component B-2 in
a weight ratio (component B-4/component B-2) of 10/90 to 90/10.
[0126] The polylactic acid (component B) particularly preferably
comprises:
(1) a combination of the component B-2 and the component B-5 in a
weight ratio (component B-2/component B-5) of 10/90 to 90/10
(combination 1), (2) a combination of the component B-3 and the
component B-5 in a weight ratio (component B-3/component B-5) of
10/90 to 90/10 (combination 2), or PS (3) a combination of the
component B-6 and the component B-2 in a weight ratio (component
B-6/component B-2) of 10/90 to 90/10 (combination 3).
[0127] The above particularly preferable combinations are
summarized below.
TABLE-US-00001 Polylactic Components Acids (mol %) Combination 1:
B-2 90 .ltoreq. [L] .ltoreq. 99 B-5 90 .ltoreq. [D] .ltoreq. 99
Combination 2: B-3 99 < [L] .ltoreq. 100 B-5 90 .ltoreq. [D]
.ltoreq. 99 Combination 3: B-2 90 .ltoreq. [L] .ltoreq. 99 B-6 99
< [D] .ltoreq. 100 [L]: L-lactic acid unit [D]: D-lactic acid
unit
[0128] As can be understood from the above description, a
combination of the component B-3 and the component B-6 is excluded
from the above particularly preferable combinations.
[0129] The weight ratio of the poly-L-lactic acid to the
poly-D-lactic acid (poly-L-lactic acid/poly-D-lactic acid) in the
polylactic acid (component B) is 10/90 to 90/10. To form more
stereocomplexes, the weight ratio is preferably 25/75 to 75/25,
more preferably 40/60 to 60/40. When the weight ratio of one of the
polymers is lower than 10 or higher than 90, homocrystallization is
prioritized, thereby making formation of the stereocomplex
difficult disadvantageously.
[0130] As the copolymerizable components other than lactic acid in
the polylactic acid (component B), units derived from a
dicarboxylic acid, polyhydric alcohol, hydroxycarboxylic acid,
lactone or the like that has two or more ester-bond-formable
functional groups and units derived from various polyesters,
various polyethers, various polycarbonates or the like that
comprise the above various constituents can be used alone or in
admixture of two or more.
[0131] Illustrative examples of the dicarboxylic acid include
succinic acid, adipic acid, azelaic acid, sebacic acid,
terephthalic acid, and isophthalic acid. Illustrative examples of
the polyhydric alcohol include aliphatic polyhydric alcohols such
as ethylene glycol, propylene glycol, butanediol, pentanediol,
hexanediol, octanediol, glycerin, sorbitan, neopentyl glycol,
diethylene glycol, triethylene glycol, polyethylene glycol and
polypropylene glycol, and aromatic polyhydric alcohols such as one
resulting from addition of ethylene oxide to bisphenol.
Illustrative examples of the hydroxycarboxylic acid include
glycolic acid and hydroxybutyl carboxylic acid. Illustrative
examples of the lactone include glycolide, .epsilon.-caprolactone
glycolide, .epsilon.-caprolactone, .beta.-propiolactone,
.delta.-butyrolactone, .beta.- or .gamma.-butyrolactone,
pivalolactone, and .delta.-valerolactone.
(Production of Poly-L-Lactic Acid or Poly-D-Lactic Acid)
[0132] The poly-L-lactic acid or poly-D-lactic acid can be produced
by a known polylactic acid polymerization method. For example, they
can be produced by a method such as ring-opening polymerization of
lactide, dehydration and condensation of lactic acid, or a
combination of these methods with solid-phase polymerization.
[0133] When the poly-L-lactic acid or poly-D-lactic acid is
produced, a lactide that is a cyclic dimer of lactic acid may be
produced as a by-product. Each polylactic acid may contain the
lactide in an amount that does not impair the stability of the
resin. After completion of polymerization of the polylactic acid,
the lactide contained in the polylactic acid is preferably removed
from the polylactic acid by a method of removing it in molten state
under reduced pressure, a method of extracting and removing it by
use of a solvent, or other method, so as to improve the thermal
stability of the resin. The content of the lactide in the
polylactic acid is not higher than 2%, preferably not higher than
1%, more preferably not higher than 0.5%, based on the polylactic
acid.
[0134] The poly-L-lactic acid or poly-D-lactic acid may contain a
catalyst for the polymerization in an amount that does not impair
the thermal stability of the resin. Illustrative examples of such a
catalyst include various tin compounds, aluminum compounds,
titanium compounds, zirconium compounds, calcium compounds, organic
acids, and inorganic acids. Illustrative examples of such a
catalyst further include fatty acid salts of tin, aluminum,
zirconium and titanium, and, carbonates, sulfates, phosphates,
oxides, hydroxides, halides and alcoholates of these metals, or
these metals themselves. Specific examples thereof include tin
octylate, aluminum acetylacetonate, aluminum alkoxide, titanium
alkoxide, and zirconium alkoxide. After completion of the
polymerization reaction of the polylactic acid, the polymerization
catalyst contained in the poly-L-lactic acid or poly-D-lactic acid
is preferably removed or deactivated by a method of extracting and
removing it by use of a solvent, a method of causing to coexist a
known stabilizer that deactivates the catalyst or other method, so
as to improve the thermal stability of the resin.
(Formation of Stereocomplex)
[0135] The poly-L-lactic acid and poly-D-lactic acid may be mixed
with the thermoplastic resin (component A) and other components to
produce the resin composition.
[0136] However, before mixed with the thermoplastic resin
(component A) and other components, the poly-L-lactic acid and the
poly-D-lactic acid are preferably caused to coexist and
heat-treated to form a stereocomplex.
[0137] The heat treatment is preferably carried out with the
poly-L-lactic acid (components B-1 to B-3) and the poly-D-lactic
acid (components B-4 to B-6) coexisting in a weight ratio of 10/90
to 90/10 and kept in a temperature range of 245 to 300.degree. C.
The heat treatment temperature is more preferably 270 to
300.degree. C., much more preferably 280 to 290.degree. C. If it
exceeds 300.degree. C., it becomes difficult to inhibit a
decomposition reaction disadvantageously. Although not particularly
limited, the heat treatment time is 0.2 to 60 minutes, preferably 1
to 20 minutes. The heat treatment can be carried out in an inert
atmosphere at normal pressure or under reduced pressure.
[0138] The heat treatment can be carried out by melt-kneading the
poly-L-lactic acid and the poly-D-lactic acid. The heat treatment
is preferably carried out by a method comprising mixing given
amounts of the poly-L-lactic acid and the poly-ID-lactic acid in
the form of fine particles or chips together and then melt-kneading
them. Further, it is also possible to melt one of the poly-L-lactic
acid and the poly-D-lactic acid, add the other polymer and knead
them. In the heat treatment, the poly-L-lactic acid and the
poly-D-lactic acid are preferably mixed together as uniformly as
possible.
[0139] Although the size of the fine particles or chips is not
particularly limited as long as the fine particles or chips of the
poly-L-lactic acid and poly-D-lactic acid are mixed uniformly, they
preferably have a size of not larger than 3 mm, more preferably 1
to 0.25 mm. When they are mixed together in the form of fine
particles or chips, a tumbler-type powder blender, a continuous
powder blender, various milling machines or the like can be
used.
[0140] To melt-knead the poly-L-lactic acid (components B-1 to B-3)
and the poly-D-lactic acid (components B-4 to B-6), a batch-type
reactor having stirring blades, a continuous reactor or a
twin-screw or single-screw extruder can be used.
[0141] Further, after the poly-L-lactic acid and the poly-D-lactic
acid are mixed together in the presence of a solvent, the mixture
may be obtained by reprecipitating it or by removing the solvent by
heating. When they are mixed together in the presence of a solvent,
it is preferable to mix separate solutions prepared by dissolving
the poly-L-lactic acid and the poly-D-lactic acid in a solvent,
respectively, or to mix the poly-L-lactic acid and the
poly-D-lactic acid by dissolving them in a solvent together. The
solvent is not particularly limited as long as the poly-L-lactic
acid and the poly-D-lactic acid can be dissolved therein.
[0142] As the solvent, chloroform, methylene chloride,
dichloroethane, tetrachloroethane, phenol, tetrahydrofuran,
N-methylpyrrolidone, N,N-dimethyl formamide, butyrolactone,
trioxane, hexafluoroisopropanol or the like can be used alone or in
admixture of two or more. Even if the solvent exists, the solvent
evaporates by heating, and the heat treatment can be carried out in
the presence of no solvent. The temperature elevation rate after
evaporation of the solvent (heat treatment) is not particularly
limited, but the heat treatment is preferably carried out in a
short time since the polymers may be decomposed when heat-treated
for a long time.
[0143] In the resin composition of the present invention, the
content of the polylactic acid (component B) is 1 to 200 parts by
weight, preferably 10 to 190 parts by weight, more preferably 20 to
180 parts by weight, based on 100 parts by weight of the
thermoplastic resin (component A).
(Physical Properties of Resin Composition)
[0144] The resin composition of the present invention shows a
proportion (R.sub.195 or higher) of melt peaks at 195.degree. C. or
higher to all melt peaks in a temperature rising process in
measurement by a differential scanning calorimeter (DSC) of at
least 20%, preferably at least 50%, more preferably at least 80%,
much more preferably at least 90%, particularly preferably at least
95%. The larger the R.sub.195 or higher is, the higher the
hydrolysis resistance of a molded article becomes. High R.sub.195
or higher indicates a high content of stereocomplex crystals.
[0145] A polylactic acid having high R.sub.195 or higher can be
produced by melt-kneading the poly-L-lactic acid and the
poly-D-lactic acid at high temperatures of 245 to 300.degree.
C.
[0146] The R.sub.195 or higher is obtained as follows. A
measurement is made by use of DSC in a nitrogen atmosphere at a
temperature elevation rate of 20.degree. C./min, and the proportion
(%) of melt peaks at 195.degree. C. or higher is calculated from a
melt peak area at 195.degree. C. or higher (high temperatures) and
a melt peak area at 140 to 180.degree. C. (low temperatures) in
accordance with the following formula.
R.sub.195 or higher (%)=A.sub.195 or higher/(A.sub.195 or
higher+A.sub.140 to 180).times.100
R.sub.195 or higher: proportion of melt peaks at 195.degree. C. or
higher
A.sub.195 or higher: melt peak area at 195.degree. C. or higher
A.sub.140 to 180: melt peak area at 140 to 180.degree. C.
[0147] When a DSC measurement is conducted on the resin composition
of the present invention, a melt peak derived from the
thermoplastic resin (component A) and melt peaks derived from the
polylactic acid emerge at different positions, and they can be
easily differentiated accordingly.
[0148] The resin composition of the present invention has a melting
point of preferably 195 to 250.degree. C., more preferably 200 to
220.degree. C., and a fusion enthalpy of preferably at least 20
J/g, more preferably at least 30 J/g. The resin composition of the
present invention preferably has an R.sub.195 or higher of at least
30%, a melting point of 195 to 250.degree. C. and a fusion enthalpy
of at least 20 J/g.
[0149] The resin composition of the present invention has excellent
heat resistance, hydrolysis resistance and chemical resistance,
because it contains the polylactic acid having a high content of
stereocomplex crystals and the thermoplastic resin. The retention
of the viscosity average molecular weight of the resin composition
of the present invention is preferably at least 30%, more
preferably at least 60%, much more preferably at least 70%.
<Crystal Nucleating Agent: Component C>
[0150] The crystal nucleating agent (component C) used in the
present invention is primarily a known compound which is commonly
used as a crystal nucleating agent for crystalline resins such as
polylactic acids and thermoplastic resins.
[0151] Illustrative examples thereof include inorganic fine
particles such as talc, silica, graphite, carbon powder,
pyroferrite, gypsum and neutral clay, metal oxides such as
magnesium oxide, aluminum oxide and titanium dioxide, sulfate,
phosphate, phosphonate, silicate, oxalate, stearate, benzoate,
salicylate, tartrate, sulfonate, montan wax salt, montan wax ester
salt, terephthalate, benzoate, and carboxylate.
[0152] Of these compounds which are used as the crystal nucleating
agent (component C), talc is particularly effective. Talc having an
average particle diameter of not larger than 20 .mu.m is preferably
used, and talc having an average particle diameter of not larger
than 5 .mu.m is more preferably used.
[0153] The content of the crystal nucleating agent cannot be
determined uniformly, because an amount in which the crystal
nucleating agent exhibits its effect differs according to the type
and shape of the crystal nucleating agent. However, the content
thereof is 0.01 to 5 parts by weight, preferably 0.05 to 3 parts by
weight, more preferably 0.1 to 2 parts by weight, based on 100
parts by weight of the polylactic acid (component B). When the
amount of the crystal nucleating agent added is too small, the
effect of the crystal nucleating agent is not exhibited, while when
it is too large, mechanical properties and the like may be
adversely affected, not to mention that the effect of the crystal
nucleating agent is not enhanced.
[0154] A method of adding the crystal nucleating agent (component
C) is not particularly limited. However, it is preferable to add it
after the poly-L-lactic acid and the poly-D-lactic acid are
melt-kneaded to form a stereocomplex, because an adverse effect on
formation of the stereocomplex is small.
<Inorganic Filler: Component D>
[0155] In the resin composition of the present invention, an
inorganic filler (component D) can be added to improve mechanical
properties, dimensional properties and the like.
[0156] As the inorganic filler (component D), generally known
inorganic fillers can be used, such as glass fibers, carbon fibers,
glass flakes, wollastonite, kaolin clay, mica, talc and various
whiskers (such as potassium titanate whiskers and aluminum borate
whiskers). The shape of the inorganic filler can be selected freely
from fibrous, flaky, spherical and hollow shapes. For improvements
in the strength and impact resistance of the resin composition, a
fibrous or flaky inorganic filler is suitable.
[0157] In particular, the inorganic filler is suitably an inorganic
filler comprising a ground natural mineral, more suitably an
inorganic filler comprising a ground natural silicate and is
preferably mica, talc or wollastonite in view of its shape.
[0158] Meanwhile, since these inorganic fillers are nonoil resource
materials that will replace oil resource materials such as carbon
fibers, use of these raw materials that cause lower environmental
burdens emphasizes significance of use of the components B and C
that cause low environmental burdens. Further, the above more
suitable inorganic filler exerts an advantageous effect that it
develops better flame retardancy than carbon fibers or the
like.
[0159] The average particle diameter of the mica is a number
average particle diameter calculated by number average of 1,000
particles having a size of at least 1 .mu.m extracted by
observation using a scanning electron microscope. The number
average particle diameter is preferably 10 to 500 .mu.m, more
preferably 30 to 400 .mu.m, much more preferably 30 to 200 most
preferably 35 to 80 .mu.m. When the number average particle
diameter is smaller than 10 .mu.m, impact strength may deteriorate.
Meanwhile, when it is larger than 500 .mu.m, impact strength
improves, but the appearance is liable to deteriorate.
[0160] The thickness of the mica can be 0.01 to 10 preferably 0.1
to 5 .mu.m, as thickness measured by observation using an electron
microscope. The aspect ratio of the mica can be 5 to 200,
preferably 10 to 100. The mica is preferably muscovite mica, and
its Mohs hardness is about 3. The muscovite mica can achieve higher
rigidity and higher strength and provides a more suitable molded
article than other micas such as phlogopite.
[0161] Further, a method of milling the mica is a dry milling
method of milling raw mica in a dry mill. Another method of milling
the mica is a wet milling method comprising coarse-milling raw mica
in a dry mill, adding a milling aid such as water, subjecting the
resulting slurry to actual milling in a wet mill, and dehydrating
and drying the resulting product. Although mica produced by either
of the milling methods can be used, the dry milling method is less
costly and more common. On the other hand, the wet milling method
is effective for milling mica more thinly and finely, but is
costly. The mica may be surface-treated with various surface
treatment agents such as a silane coupling agent, higher fatty acid
ester and wax and may be granulated by sizing agents such as
various resins, higher fatty acid ester and wax.
[0162] Talc that can be used in the present invention is scale-like
particles that have a layered structure and is hydrous magnesium
silicate in terms of chemical composition. The talc is generally
represented by a chemical formula 4SiO.sub.2.3MgO.2H.sub.2O and
generally contains 56 to 65 wt % of SiO.sub.2, 28 to 35 wt % of MgO
and about 5 wt % of H.sub.2O. The talc also contains other
components in small amounts, such as 0.03 to 1.2 wt % of
Fe.sub.2O.sub.3, 0.05 to 1.5 wt % of Al.sub.2O.sub.3, 0.05 to 1.2
wt % of CaO, up to 0.2 wt % of K.sub.2O, and up to 0.2 wt % of
Na.sub.2O. The talc has a specific viscosity of about 2.7 and a
Mohs hardness of 1.
[0163] The average particle diameter of the talc is preferably 0.5
to 30 .mu.m. The average particle diameter is a particle diameter
at an accumulation rate of 50% which is determined from particle
size distribution measured by an Andreasen pipette method measured
in accordance with JIS M8016. The particle diameter of the talc is
more preferably 2 to 30 .mu.m, much more preferably 5 to 20 .mu.m,
most preferably 10 to 20 .mu.m. Talc having a particle diameter of
0.5 to 30 .mu.m provides not only rigidity and low anisotropy but
also a good surface appearance and flame retardancy to the resin
composition.
[0164] Further, a method of milling a raw stone to produce the talc
is not particularly limited, and axial-flow milling, annular
milling, roll milling, ball milling, jet milling and
container-rotating compression shear milling can be used. Further,
milled talc is suitably classified by various classifiers to
achieve uniform particle size distribution. The classifiers are not
particularly limited. Illustrative examples thereof include
impactor-type inertial classifiers (such as a variable impactor),
inertial classifiers using the Coanda effect (such as an elbow
jet), and centrifugal classifiers (such as a multistage cyclone,
Microplex, dispersion separator, AccuCut, turbo classifier,
Turboplex, micron separator, and super separator).
[0165] Further, the talc is preferably in an aggregated state in
view of ease of its handling or the like. Illustrative examples of
a method of producing aggregated talc include a method of
compressing the talc by deaeration, and a method of compressing the
talc by use of a sizing agent. In particular, the method of
compressing the talc by deaeration is preferred because it is easy
to practice and prevents unwanted sizing agent resin components
from being mixed into the molded article of the present
invention.
[0166] Further, wollastonite that can be used in the present
invention is virtually represented by a chemical formula
CaSiO.sub.3 and generally contains at least about 50 wt % of
SiO.sub.2 and at least about 47 wt % of CaO, in addition to
Fe.sub.2O.sub.3 and Al.sub.2O.sub.3. The wollastonite is white
needle-like powder obtained by milling and classifying rough
wollastonite and has a Mohs hardness of about 4.5. The average
fiber diameter of the wollastonite is preferably 0.5 to 20 .mu.m,
more preferably 0.5 to 10 .mu.m, most preferably 1 to 5 .mu.m. The
average fiber diameter is calculated by number average of 1,000
fibers having a fiber diameter of at least 0.1 .mu.m extracted by
observation using a scanning electron microscope.
[0167] Some of these inorganic fillers can serve as the crystal
nucleating agent which is the component C.
[0168] However, they are considered as the inorganic filler
(component D) when used to improve mechanical properties and the
like.
[0169] The content of the inorganic filler (component D) is
preferably 0.3 to 200 parts by weight, more preferably 1 to 100
parts by weight, much more preferably 3 to 50 parts by weight,
based on 100 parts by weight of the thermoplastic resin (component
A). When the content of the component D is lower than 0.3 parts by
weight, its effect of reinforcing the mechanical properties of the
molded article is not sufficient, while when it is higher than 200
parts by weight, moldability and color deteriorate
disadvantageously.
<Terminal Blocking Agent: Component E>
[0170] In the resin composition of the present invention, when a
terminal blocking agent (component E) is contained, hydrolysis
resistance can be improved.
[0171] The terminal blocking agent (component E) reacts with some
or all of carboxyl group terminals of the polylactic acid
(component B) in the resin composition of the present invention to
block them. Illustrative examples thereof include
condensation-reaction-type compounds such as aliphatic alcohols and
amide compounds, and addition-reaction-type compounds such as
carbodiimide compounds, epoxy compounds, oxazoline compounds,
oxazine compounds and aziridine compounds. When the latter
addition-reaction-type compound is used, there is no need to
discharge an unwanted by-product out of a reaction system, as in
the case of terminal blocking by a dehydration condensation
reaction of alcohol with carboxyl group, for example.
[0172] Accordingly, by adding an addition-reaction-type terminal
blocking agent when the poly-L-lactic acid (components B-1 to B-3)
and the poly-D-lactic acid (components B-4 to B-6) are
melt-kneaded, a sufficient carboxyl group terminal blocking effect
can be achieved while decomposition of the resin by a by-product is
inhibited. As a result, the hydrolysis resistance of the
stereocomplex polylactic acid can be improved.
[0173] As the carbodiimide compounds (including polycarbodiimide
compounds), those synthesized by generally well-known methods can
be used. Illustrative examples thereof include those which can be
synthesized by subjecting various polyisocyanates to a
decarboxylation condensation reaction by use of an organophosphorus
or organometallic compound as a catalyst, at a temperature of at
least about 70.degree. C., in the presence of an inert solvent or
no solvent.
[0174] Illustrative examples of monocarbodiimide compounds included
in the carbodiimide compounds include dicyclohexyl carbodiimide,
diisopropyl carbodiimide, dimethyl carbodiimide, diisobutyl
carbodiimide, dioctyl carbodiimide, t-butyl isopropyl carbodiimide,
diphenyl carbodiimide, di-t-butyl carbodiimide, and
di-.beta.-naphthyl carbodiimide. Of these, dicyclohexyl
carbodiimide or diisopropyl carbodiimide is suitable particularly
because they are industrially easily available.
[0175] Further, as the polycarbodiimide compounds included in the
above carbodiimide compounds, those produced by various methods can
be used. Basically, those produced by a conventional method of
producing a polycarbodiimide (U.S. Pat. No. 2,941,956, Japanese
Patent Publication No. 47-33279, J. Org. Chem. 28, 2069 to 2075
(1963), Chemical Review 1981, Vol. 81, No. 4, pp. 619 to 621) can
be used.
[0176] Illustrative examples of an organic diisocyanate which is a
synthetic raw material in production of the polycarbodiimide
compound include an aromatic diisocyanate, aliphatic diisocyanate,
alicyclic diisocyanate, and mixtures thereof. Specific examples
thereof include 1,5-naphthalene diisocyanate, 4,4'-diphenylmethane
diisocyanate, 4,4'-diphenyldimethylmethane diisocyanate,
1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate,
2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, a mixture of
2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate,
hexamethylene diisocyanate, cyclohexane-1,4-diisocyanate, xylylene
diisocyanate, isophorone diisocyanate,
dicyclohexylmethane-4,4'-diisocyanate, methyl cyclohexane
diisocyanate, tetramethylxylylene diisocyanate,
2,6-diisopropylphenyl isocyanate, and
1,3,5-triisopropylbenzene-2,4-diisocyanate.
[0177] Further, in the case of the polycarbodiimide compound, it
can be controlled to an appropriate polymerization degree by use of
a compound such as a monoisocyanate that reacts with a terminal
isocyanate of the polycarbodiimide compound.
[0178] Illustrative examples of the monoisocyanate for controlling
the polymerization degree of the polycarbodiimide compound by
blocking the terminal of the polycarbodiimide compound include
phenyl isocyanate, tolyl isocyanate, dimethylphenyl isocyanate,
cyclohexyl isocyanate, butyl isocyanate, and naphthyl
isocyanate.
[0179] Illustrative examples of the epoxy compounds as the terminal
blocking agent (component E) include N-glycidyl phthalimide,
N-glycidyl-4-methyl phthalimide, N-glycidyl-4,5-dimethyl
phthalimide, N-glycidyl-3-methyl phthalimide,
N-glycidyl-3,6-dimethyl phthalimide, N-glycidyl-4-ethoxy
phthalimide, N-glycidyl-4-chlorophthalimide,
N-glycidyl-4,5-dichlorophthalamide,
N-glycidyl-3,4,5,6-tetrabromophthalimide,
N-glycidyl-4-n-butyl-5-bromophthalimide, N-glycidyl succinimide,
N-glycidyl hexahydrophthalimide,
N-glycidyl-1,2,3,6-tetrahydrophthalimide, N-glycidyl maleinimide,
N-glycidyl-.alpha.,.beta.-dimethyl succinimide,
N-glycidyl-.alpha.-ethyl succinimide, N-glycidyl-.alpha.-propyl
succinimide, N-glycidyl benzamide, N-glycidyl-p-methyl benzamide,
N-glycidyl naphthamide, N-glycidyl steramide,
N-methyl-4,5-epoxycyclohexane-1,2-dicarboxylic imide,
N-ethyl-4,5-epoxycyclohexane-1,2-dicarboxylic imide,
N-phenyl-4,5-epoxycyclohexane-1,2-dicarboxylic imide,
N-naphthyl-4,5-epoxycyclohexane-1,2-dicarboxylic imide,
N-tolyl-3-methyl-4,5-epoxycyclohexane-1,2-dicarboxylic imide,
o-phenylphenyl glycidyl ether, 2-methyloctyl glycidyl ether, phenyl
glycidyl ether, 3-(2-xenyloxy)-1,2-epoxypropane, allyl glycidyl
ether, butyl glycidyl ether, lauryl glycidyl ether, benzyl glycidyl
ether, cyclohexyl glycidyl ether, .alpha.-cresyl glycidyl ether,
p-t-butylphenyl glycidyl ether, methacrylic glycidyl ether,
ethylene oxide, propylene oxide, styrene oxide, octylene oxide,
hydroquinone diglycidyl ether, resorcin diglycidyl ether,
1,6-hexanediol diglycidyl ether, and hydrogenated bisphenol
A-diglycidyl ether.
[0180] Illustrative examples of the epoxy compounds further include
diglycidyl terephthalate, diglycidyl tetrahydrophthalate,
diglycidyl hexahydrophthalate, dimethyl diglycidyl phthalate,
phenylene diglycidyl ether, ethylene diglycidyl ether, trimethylene
diglycidyl ether, tetramethylene diglycidyl ether, and
hexamethylene diglycidyl ether.
[0181] One or more compounds are arbitrarily selected out of these
epoxy compounds to block the carboxyl terminal of the polylactic
acid unit. From the viewpoint of reactivity, ethylene oxide,
propylene oxide, phenyl glycidyl ether, o-phenylphenyl glycidyl
ether, p-t-butylphenyl glycidyl ether, N-glycidyl phthalimide,
hydroquinone diglycidyl ether, resorcin diglycidyl ether,
1,6-hexanediol diglycidyl ether, hydrogenated bisphenol
A-diglycidyl ether and the like are preferred.
[0182] Illustrative examples of the oxazoline compounds as the
terminal blocking agent (component E) include
2-methoxy-2-oxazoline, 2-ethoxy-2-oxazoline, 2-propoxy-2-oxazoline,
2-butoxy-2-oxazoline, 2-pentyloxy-2-oxazoline,
2-hexyloxy-2-oxazoline, 2-heptyloxy-2-oxazoline,
2-octyloxy-2-oxazoline, 2-nonyloxy-2-oxazoline,
2-decyloxy-2-oxazoline, 2-cyclopentyloxy-2-oxazoline,
2-cyclohexyloxy-2-oxazoline, 2-allyloxy-2-oxazoline,
2-methallyloxy-2-oxazoline, 2-crotyloxy-2-oxazoline,
2-phenoxy-2-oxazoline, 2-cresyl-2-oxazoline,
2-o-ethylphenoxy-2-oxazoline, 2-o-propylphenoxy-2-oxazoline,
2-o-phenylphenoxy-2-oxazoline, 2-m-ethylphenoxy-2-oxazoline,
2-m-propylphenoxy-2-oxazoline, 2-p-phenylphenoxy-2-oxazoline,
2-methyl-2-oxazoline, 2-ethyl-2-oxazoline, 2-propyl-2-oxazoline,
2-butyl-2-oxazoline, 2-pentyl-2-oxazoline, 2-hexyl-2-oxazoline,
2-heptyl-2-oxazoline, 2-octyl-2-oxazoline, 2-nonyl-2-oxazoline,
2-decyl-2-oxazoline, 2-cyclopentyl-2-oxazoline,
2-cyclohexyl-2-oxazoline, 2-allyl-2-oxazoline,
2-methallyl-2-oxazoline, 2-crotyl-2-oxazoline,
2-phenyl-2-oxazoline, 2-o-ethylphenyl-2-oxazoline,
2-o-propylphenyl-2-oxazoline, 2-o-phenylphenyl-2-oxazoline,
2-m-ethylphenyl-2-oxazoline, 2-m-propylphenyl-2-oxazoline,
2-p-phenylphenyl-2-oxazoline, 2,2'-bis(2-oxazoline),
2,2'-bis(4-methyl-2-oxazoline),
2,2'-bis(4,4'-dimethyl-2-oxazoline), 2,2'-bis(4-ethyl-2-oxazoline),
2,2'-bis(4,4'-diethyl-2-oxazoline), 2,2'-bis(4-propyl-2-oxazoline),
2,2'-bis(4-butyl-2-oxazoline), 2,2'-bis(4-hexyl-2-oxazoline),
2,2'-bis(4-phenyl-2-oxazoline), 2,2'-bis(4-cyclohexyl-2-oxazoline),
2,2'-bis(4-benzyl-2-oxazoline), 2,2'-p-phenylenebis(2-oxazoline),
2,2'-m-phenylenebis(2-oxazoline), 2,2'-o-phenylenebis(2-oxazoline),
2,2'-p-phenylenebis(4-methyl-2-oxazoline),
2,2'-p-phenylenebis(4,4'-dimethyl-2-oxazoline),
2,2'-m-phenylenebis(4-methyl-2-oxazoline),
2,2'-m-phenylenebis(4,4'-dimethyl-2-oxazoline),
2,2'-ethylenebis(2-oxazoline), 2,2'-tetramethylenebis(2-oxazoline),
2,2'-hexamethylenebis(2-oxazoline),
2,2'-octamethylenebis(2-oxazoline),
2,2'-decamethylenebis(2-oxazoline),
2,2'-ethylenebis(4-methyl-2-oxazoline),
2,2'-tetramethylenebis(4,4'-dimethyl-2-oxazoline),
2,2'-9,9'-diphenoxyethanebis(2-oxazoline),
2,2'-cyclohexylenebis(2-oxazoline), and
2,2'-diphenylenebis(2-oxazoline). Illustrative examples of the
oxazoline compounds further include polyoxazoline compounds
containing the above compounds as monomer units, such as a
styrene.cndot.2-isopropenyl-2-oxazoline copolymer. One or more
compounds are arbitrarily selected out of these oxazoline compounds
to block the carboxyl terminal of the polylactic acid unit.
[0183] Illustrative examples of the oxazine compounds as the
terminal blocking agent (component E) include
2-methoxy-5,6-dihydro-4H-1,3-oxazine,
2-ethoxy-5,6-dihydro-4H-1,3-oxazine,
2-propoxy-5,6-dihydro-4H-1,3-oxazine,
2-butoxy-5,6-dihydro-4H-1,3-oxazine,
2-pentyloxy-5,6-dihydro-4H-1,3-oxazine,
2-hexyloxy-5,6-dihydro-4H-1,3-oxazine,
2-heptyloxy-5,6-dihydro-4H-1,3-oxazine,
2-octyloxy-5,6-dihydro-4H-1,3-oxazine,
2-nonyloxy-5,6-dihydro-4H-1,3-oxazine,
2-decyloxy-5,6-dihydro-4H-1,3-oxazine,
2-cyclopentyloxy-5,6-dihydro-4H-1,3-oxazine,
2-cyclohexyloxy-5,6-dihydro-4H-1,3-oxazine,
2-allyloxy-5,6-dihydro-4H-1,3-oxazine,
2-methallyloxy-5,6-dihydro-4H-1,3-oxazine,
2-crotyloxy-5,6-dihydro-4H-1,3-oxazine,
2,2'-bis(5,6-dihydro-4H-1,3-oxazine),
2,2'-methylenebis(5,6-dihydro-4H-1,3-oxazine),
2,2'-ethylenebis(5,6-dihydro-4H-1,3-oxazine),
2,2'-propylenebis(5,6-dihydro-4H-1,3-oxazine),
2,2'-butylenebis(5,6-dihydro-4H-1,3-oxazine),
2,2'-hexamethylenebis(5,6-dihydro-4H-1,3-oxazine),
2,2'-p-phenylenebis(5,6-dihydro-4H-1,3-oxazine),
2,2'-m-phenylenebis(5,6-dihydro-4H-1,3-oxazine),
2,2'-naphthylenebis(5,6-dihydro-4H-1,3-oxazine), and
2,2'-P,P'-diphenylenebis(5,6-dihydro-4H-1,3-oxazine).
[0184] Illustrative examples of the oxazine compounds further
include polyoxazine compounds containing the above compounds as
monomer units. One or more compounds are arbitrarily selected out
of these oxazine compounds to block the carboxyl terminal of the
polylactic acid unit.
[0185] Further, one or more compounds may be arbitrarily selected
out of the above oxazoline compounds and oxazine compounds and used
in combination to block the carboxyl terminal of the polylactic
acid. In view of heat resistance, reactivity and affinity for
aliphatic polyesters, 2,2'-m-phenylenebis(2-oxazoline) and
2,2'-p-phenylenebis(2-oxazoline) are preferred.
[0186] Illustrative examples of the aziridine compounds as the
terminal blocking agent (component E) include an addition reaction
product of mono, bis or polyisocyanate compound and ethylene
imine.
[0187] Further, two or more compounds out of the carbodiimide
compounds, epoxy compounds, oxazoline compounds, oxazine compounds
and aziridine compounds described above as the terminal blocking
agents that can be used in the present invention can be used in
combination as the terminal blocking agent.
[0188] In the resin composition of the present invention, blocking
of the carboxyl terminal group is carried out to a proper extent
according to intended use. As for a specific degree of blocking of
the carboxyl group terminals, the concentration of the carboxyl
group terminals of the polylactic acid is preferably not higher
than 10 equivalent/10.sup.3 kg, more preferably not higher than 6
equivalent/10.sup.3 kg, from the viewpoint of an improvement in
hydrolysis resistance.
[0189] As a method for blocking the carboxyl group terminals of the
polylactic acid (component B) in the resin composition of the
present invention, a condensation-reaction-type or
addition-reaction-type terminal blocking agent is reacted with the
terminals.
[0190] As a method of blocking the carboxyl group terminals by a
condensation reaction, the carboxyl group terminals can be blocked
by adding a proper amount of a condensation-reaction-type terminal
blocking agent such as an aliphatic alcohol or amide compound into
a polymerization system at the time of polymerization of the
polymer to cause a dehydration condensation reaction under reduced
pressure. To achieve a high polymerization degree of the polymer,
the condensation-reaction-type terminal blocking agent is
preferably added upon completion of the polymerization
reaction.
[0191] As a method of blocking the carboxyl group terminals by an
addition reaction, the carboxyl group terminals can be blocked by
reacting the terminals with a proper amount of a terminal blocking
agent such as a carbodiimide compound, epoxy compound, oxazoline
compound, oxazine compound or aziridine compound, with the
polylactic acid in a molten state. The terminal blocking agent can
be added to and reacted with the terminals after completion of the
polymerization reaction of the polymer.
[0192] When the poly-L-lactic acid (components B-1 to B-3) and the
poly-D-lactic acid unit (components B-4 to B-6) are melt-kneaded in
the presence of the terminal blocking agent (component E),
decomposition and degradation of the thermoplastic resin (component
A) are inhibited.
[0193] The content of the terminal blocking agent (component E) is
preferably 0.01 to 5 parts by weight, more preferably 0.05 to 4
parts by weight, much more preferably 0.1 to 3 parts by weight,
based on 100 parts by weight of the polylactic acid (component
B).
<Flame Retardant: Component F>
[0194] The resin composition of the present invention can also
contain a flame retardant. Illustrative examples of the flame
retardant include halogen-containing flame retardants such as a
brominated epoxy resin, brominated polystyrene, brominated
polycarbonate, brominated polyacrylate and chlorinated
polyethylene; phosphate-containing flame retardants such as
monophosphate compounds and phosphate oligomer compounds;
organophosphorus flame retardants other than phosphate-based flame
retardants, such as phosphonate oligomer compounds, phosphonitrile
oligomer compounds and amide phosphonate compounds;
organometallic-salt-containing flame retardants such as organic
sulfonic acid alkali (earth) metal salts,
boric-acid-metallic-salt-containing flame retardants and
stannic-acid-metallic-salt-containing flame retardants; and
silicone-containing flame retardants. Further, the flame retardant
may be used in combination with a flame retarding aid (such as
sodium antimonate or antimony trioxide) or a dripping inhibitor
(such as a polytetrafluoroethylene having a fibril forming
ability).
[0195] Of the above flame retardants, compounds that do not contain
a chlorine atom and a bromine atom are more suitable as the flame
retardant in the molded article of the present invention which is
characterized by a reduction of environmental burdens, since
factors considered unfavorable when waste incineration or thermal
recycling is carried out are reduced.
[0196] Further, the phosphate-containing flame retardants are
particularly preferred, because they provide good color and also
exert an effect of improving moldability. Specific examples of the
phosphate-containing flame retardants particularly include one or
more phosphate compounds represented by the following general
formula (II):
##STR00002##
wherein X is a group derived from hydroquinone, resorcinol,
bis(4-hydroxydiphenyl)methane, bisphenol A, dihydroxydiphenyl,
dihydroxy naphthalene, bis(4-hydroxyphenyl)sulfone,
bis(4-hydroxyphenyl)ketone or bis(4-hydroxyphenyl)sulfide, n is an
integer of 0 to 5 and is the average of 0 to 5 in the case of a
blend of phosphates differing in the value of n, and R.sup.11,
R.sup.12, R.sup.13 and R.sup.14 are each independently a group
derived from phenol, cresol, xylenol, isopropylphenol, butylphenol
or p-cumylphenol in which are substituted or unsubstituted by one
or more halogen atoms.
[0197] More preferably, X in the formula is a group derived from
hydroquinone, resorcinol, bisphenol A or dihydroxydiphenyl, n is an
integer of 1 to 3 or the average thereof in the case of a blend of
phosphates differing in the value of n, and R.sup.11, R.sup.12,
R.sup.13 and R.sup.14 are each independently a group derived from
phenol, cresol or xylenol in which are substituted or more suitably
unsubstituted one or more halogen atoms.
[0198] Of the organophosphate flame retardants, triphenyl phosphate
is preferred as the phosphate compound. As the phosphate oligomer,
resorcinol bis(dixylenyl phosphate) and bisphenol A bis(diphenyl
phosphate) can be preferably used because they are also excellent
in hydrolysis resistance and the like. Resorcinol bis(dixylenyl
phosphate) and bisphenol A bis(diphenyl phosphate) are more
preferred in terms of heat resistance and the like, since they also
have good heat resistance and do not thermally degrade or evaporate
accordingly.
[0199] In the resin composition of the present invention, the
content of the flame retardant is preferably 0.05 to 50 parts by
weight, based on 100 parts by weight of the thermoplastic resin
(component A). When the content is lower than 0.05 parts by weight,
sufficient flame retardancy is not developed, while when it is
higher than 50 parts by weight, the strength and heat resistance of
the molded article are impaired.
<Heat Stabilizer: Component P>
[0200] The resin composition of the present invention preferably
contains a phosphorus stabilizer to obtain better color and stable
flowability. In particular, the composition preferably contains, as
the phosphorus stabilizer, a pentaerythritol-type phosphite
compound represented by the following general formula (III):
##STR00003##
wherein R.sup.1 and R.sup.2 independently represent a hydrogen
atom, an alkyl group having 1 to 20 carbon atoms, an aryl or
alkylaryl group having 6 to 20 carbon atoms, an aralkyl group
having 7 to 30 carbon atoms, a cycloalkyl group having 4 to 20
carbon atoms or a 2-(4-oxyphenyl)propyl-substituted aryl group
having 15 to 25 carbon atoms, and the cycloalkyl group and the aryl
group may be substituted with an alkyl group.
[0201] Specific examples of the pentaerythritol-type phosphite
compound include distearyl pentaerythritol diphosphite,
bis(2,4-di-t-butylphenyl)pentaerythritol diphosphite,
bis(2,6-di-t-butyl-4-methylphenyl)pentaerythritol diphosphite,
bis(2,6-di-t-butyl-4-ethylphenyl)pentaerythritol diphosphite,
phenyl bisphenol A pentaerythritol diphosphite,
bis(nonylphenyl)pentaerythritol diphosphite, and dicyclohexyl
pentaerythritol diphosphite. Of these, distearyl pentaerythritol
diphosphite and bis(2,4-di-t-butylphenyl)pentaerythritol
diphosphite are suitable.
[0202] Illustrative examples of other phosphorus stabilizers
include various phosphite compounds, phosphonite compounds and
phosphate compounds.
[0203] Specific examples of the phosphite compounds include
triphenyl phosphite, tris(nonylphenyl)phosphite, tridecyl
phosphite, trioctyl phosphite, trioctadecyl phosphite, didecyl
monophenyl phosphite, dioctyl monophenyl phosphite, diisopropyl
monophenyl phosphite, monobutyl diphenyl phosphite, monodecyl
diphenyl phosphite, monooctyl diphenyl phosphite,
2,2-methylenebis(4,6-di-t-butylphenyl)octyl phosphite,
tris(diethylphenyl)phosphite, tris(di-iso-propylphenyl)phosphite,
tris(di-n-butylphenyl)phosphite,
tris(2,4-di-t-butylphenyl)phosphite, and
tris(2,6-di-t-butylphenyl)phosphite.
[0204] Further, as other phosphite compounds, those that react with
dihydric phenols and have a cyclic structure can also be used.
Specific examples thereof include
2,2'-methylenebis(4,6-di-t-butylphenyl)
(2,4-di-t-butylphenyl)phosphite,
2,2'-methylenebis(4,6-di-t-butylphenyl)
(2-t-butyl-4-methylphenyl)phosphite,
2,2'-methylenebis(4-methyl-6-t-butylphenyl)
(2-t-butyl-4-methylphenyl)phosphite, and
2,2'-ethylidenebis(4-methyl-6-t-butylphenyl)
(2-t-butyl-4-methylphenyl)phosphite.
[0205] Specific examples of the phosphate compounds include
tributyl phosphate, trimethyl phosphate, tricresyl phosphate,
triphenyl phosphate, trichlorophenyl phosphate, triethyl phosphate,
diphenylcresyl phosphate, diphenyl monoorthoxenyl phosphate,
tributoxyethyl phosphate, dibutyl phosphate, dioctyl phosphate, and
diisopropyl phosphate. Triphenyl phosphate and trimethyl phosphate
are preferred.
[0206] Specific examples of the phosphonite compounds include
tetrakis(2,4-di-t-butylphenyl)-4,4'-biphenylene diphosphonite,
tetrakis(2,4-di-t-butylphenyl)-4,3'-biphenylene diphosphonite,
tetrakis(2,4-di-t-butylphenyl)-3,3'-biphenylene diphosphonite,
tetrakis(2,6-di-t-butylphenyl)-4,4'-biphenylene diphosphonite,
tetrakis(2,6-di-t-butylphenyl)-4,3'-biphenylene diphosphonite,
tetrakis(2,6-di-t-butylphenyl)-3,3'-biphenylene diphosphonite,
bis(2,4-di-t-butylphenyl)-4-phenyl-phenyl phosphonite,
bis(2,4-di-t-butylphenyl)-3-phenyl-phenyl phosphonite,
bis(2,6-di-n-butylphenyl)-3-phenyl-phenyl phosphonite,
bis(2,6-di-t-butylphenyl)-4-phenyl-phenyl phosphonite, and
bis(2,6-di-t-butylphenyl)-3-phenyl-phenyl phosphonite.
Tetrakis(di-t-butylphenyl)-biphenylene diphosphonite and
bis(di-t-butylphenyl)-phenyl-phenyl phosphonite are preferred, and
tetrakis(2,4-di-t-butylphenyl)-biphenylene diphosphonite and
bis(2,4-di-t-butylphenyl)-phenyl-phenyl phosphonite are more
preferred. The phosphonite compounds can be preferably used in
combination with the above phosphite compounds having an aryl group
substituted with two or more alkyl groups.
[0207] Specific examples of the phosphonate compounds include
dimethyl benzenephosphonate, diethyl benzenephosphonate, and
dipropyl benzenephosphonate.
[0208] The phosphorus stabilizers can be used alone or in
combination of two or more. It is preferable to add at least the
pentaerythritol-type phosphite compound in an effective amount. The
phosphorus stabilizer is preferably contained in an amount of 0.001
to 1 part by weight, more preferably 0.01 to 0.5 parts by weight,
much more preferably 0.01 to 0.3 parts by weight, based on 100
parts by weight of the thermoplastic resin (component A).
<Break Inhibitor>
[0209] The resin composition of the present invention can contain a
break inhibitor for inhibiting breakage of fibrous inorganic filler
or flaky inorganic filler when the filler is used. The break
inhibitor inhibits breakage of the inorganic filler by inhibiting
adhesion between the matrix resin and the inorganic filler and
reducing stress applied to the inorganic filler at the time of
melt-kneading. Illustrative examples of effects of the break
inhibitor include (1) an improvement in rigidity (the aspect ratio
of the inorganic filler becomes large), (2) an improvement in
toughness, and (3) an improvement in electrical conductivity (in
the case of a conductive inorganic filler). Specific examples of
the break inhibitor include (i) a compound when the compound having
a low affinity for the resin is directly coated on the surface of
the inorganic filler, and (ii) a compound having a structure
showing a low affinity for the resin and having a functional group
that can react with the surface of the inorganic filler.
[0210] Representative examples of the compound having a low
affinity for the resin include various lubricants. Specific
examples of the lubricants include mineral oil, synthetic oil,
higher fatty acid ester, higher fatty acid amide,
polyorganosiloxane (such as silicone oil or silicone rubber),
olefinic wax (such as paraffin wax or polyolefin wax), polyalkylene
glycol, and fluorine oils such as fluorinated fatty acid ester,
trifluorochloroethylene and polyhexafluoropropylene glycol.
[0211] Illustrative examples of a method for coating the compound
having a low affinity for the resin directly on the surface of the
inorganic filler include (1) a method of immersing the inorganic
filler in the compound directly or in a solution or emulsion of the
compound, (2) a method of passing the inorganic filler through
vapor or powder of the compound, (3) a method of spraying powder of
the compound to the inorganic filler at high speed, and (4) a
mechanochemical method of rubbing the inorganic filler and the
compound against each other.
[0212] Illustrative examples of the compound having a structure
showing a low affinity for the resin and having a functional group
that can react with the surface of the inorganic filler include the
above lubricants modified with various functional groups.
Illustrative examples of the functional groups include a carboxyl
group, carboxylic anhydride group, epoxy group, oxazoline group,
isocyanate group, ester group, amino group, and alkoxysilyl
group.
[0213] A suitable break inhibitor is an alkoxysilane compound in
which an alkyl group having 5 or more carbon atoms is bonded to a
silicon atom. The alkyl group bonded to the silicon atom has
preferably 5 to 60, more preferably 5 to 20, much more preferably 6
to 18, particularly preferably 8 to 16 carbon atoms. The number of
the alkyl group is suitably 1 or 2, particularly preferably 1.
Further, suitable examples of the alkoxy group include a methoxy
group and an ethoxy group. The alkoxysilane compound is preferred
in that it shows high reactivity with the surface of the inorganic
filler and has excellent coating efficiency. Therefore, it is
suitable for finer inorganic fillers.
[0214] A suitable break inhibitor is polyolefin wax having at least
one functional group selected from a carboxyl group and a
carboxylic anhydride group. Its molecular weight is preferably 500
to 20,000, more preferably 1,000 to 15,000, in terms of weight
average molecular weight. The amount of the carboxyl group and
carboxylic anhydride group in the polyolefin wax is preferably 0.05
to 10 meq/g, more preferably 0.1 to 6 meq/g, much more preferably
0.5 to 4 meq/g, per gram of the lubricant having at least one
functional group selected from the carboxyl group and the
carboxylic anhydride group. The proportion of functional groups
other than the carboxyl group in the break inhibitor is preferably
nearly equal to the proportion of the above carboxyl group and
carboxylic anhydride group.
[0215] Particularly preferable as the break inhibitor is a
copolymer of .alpha.-olefin and maleic anhydride. The copolymer can
be produced by a conventional melt polymerization or bulk
polymerization method in the presence of a radical catalyst. The
.alpha.-olefin is preferably one having 10 to 60 carbon atoms on
the average. The .alpha.-olefin is more preferably one having 16 to
60 carbon atoms on the average, much more preferably one having 25
to 55 carbon atoms on the average.
[0216] The content of the break inhibitor is preferably 0.01 to 2
parts by weight, more preferably 0.05 to 1.5 parts by weight, much
more preferably 0.1 to 0.8 parts by weight, based on 100 parts by
weight of the thermoplastic resin (component A).
<Elastomeric Polymer>
[0217] In the resin composition of the present invention, an
elastomeric polymer can be used as a impact improving agent. An
example of the elastomeric polymer is a graft copolymer obtained by
copolymerization of a rubber component having a glass transition
temperature of not higher than 10.degree. C. with one or more
monomers selected from aromatic vinyl, vinyl cyanide, acrylic
ester, methacrylic ester and vinyl compounds copolymerizable with
these compounds. A more suitable elastomeric polymer is a
core-shell-type graft copolymer obtained by graft-copolymerization
of the core of the rubber component with the shell (s) of one or
more of the above monomers.
[0218] Another example of the elastomeric polymer is a block
copolymer comprising the rubber component and the above monomers.
Specific examples of the block copolymer include thermoplastic
elastomers such as a styrene-ethylene propylene-styrene elastomer
(hydrogenated styrene-isoprene-styrene elastomer) and a
hydrogenated styrene-butadiene-styrene elastomer. Further, various
other elastomeric polymers known as thermoplastic elastomers, such
as an urethane elastomer, polyester elastomer and polyether amide
elastomer, can also be used.
[0219] More suitable as the impact improving agent is a
core-shell-type graft copolymer. The particle diameter of the core
of the core-shell-type graft copolymer is preferably 0.05 to 0.8
.mu.m, more preferably 0.1 to 0.6 .mu.m, much more preferably 0.1
to 0.5 .mu.m, in terms of weight average particle diameter. With
the particle diameter of the core in a range of 0.05 to 0.8 .mu.m,
better impact resistance is achieved. The elastomeric polymer
preferably contains the rubber component in a proportion of at
least 40%, more preferably at least 60%.
[0220] Illustrative examples of the rubber component include
butadiene rubber, butadiene-acrylic composite rubber, acrylic
rubber, acrylic-silicone composite rubber, isobutylene-silicone
composite rubber, isoprene rubber, styrene-butadiene rubber,
chloroprene rubber, ethylene-propylene rubber, nitrile rubber,
ethylene-acrylic rubber, silicone rubber, epichlorohydrin rubber,
fluoro-rubber, and these compounds with their unsaturation binding
portions hydrogenated. Due to fear of generation of harmful
substances upon combustion, a rubber component containing no
halogen atom is preferred in terms of environmental burdens.
[0221] The glass transition temperature of the rubber component is
preferably not higher than -10.degree. C., more preferably not
higher than -30.degree. C. The rubber component is particularly
preferably butadiene rubber, butadiene-acrylic composite rubber,
acrylic rubber or acrylic-silicone composite rubber. The composite
rubber refers to rubber obtained by copolymerizing two rubber
components or rubber obtained by polymerizing two rubber components
such that the rubber has an IPN structure in which the rubber
components are entangled with each other so that they cannot be
separated.
[0222] Illustrative examples of the aromatic vinyl to be
copolymerized with the rubber component include styrene,
.alpha.-methylstyrene, p-methylstyrene, alkoxystyrene, and
halogenated styrene. Styrene is particularly preferred.
Illustrative examples of the acrylic ester include methyl acrylate,
ethyl acrylate, butyl acrylate, cyclohexyl acrylate, and octyl
acrylate. Illustrative examples of the methacrylic ester include
methyl methacrylate, ethyl methacrylate, butyl methacrylate,
cyclohexyl methacrylate, and octyl methacrylate. Methyl
methacrylate is particularly preferred. Of these, especially
methacrylic ester such as methyl methacrylate is preferably
contained as an essential component. The reason is that since this
shows an excellent affinity for the thermoplastic resin, more
elastomeric polymers exist in the resin and good impact resistance
of the thermoplastic resin is exerted more effectively, so that the
impact resistance of the resin composition becomes good. More
specifically, methacrylic ester is preferably contained in an
amount of at least 10 wt %, more preferably at least 15 wt %, in
100 wt % of graft component (or in 100 wt % of shell in the case of
a core-shell-type polymer).
[0223] The elastomeric polymer containing the rubber component
having a glass transition temperature of not higher than 10.degree.
C. may be produced by any of bulk polymerization, solution
polymerization, suspension polymerization and emulsion
polymerization methods. The copolymerization method may be a
one-stage graft or multistage graft. Further, it may be a mixture
with a copolymer comprising only graft components that is
by-produced upon production. Further, illustrative examples of
polymerization methods include a soap-free polymerization method
using an initiator such as potassium persulfate, a seed
polymerization method, and a two-stage swelling polymerization
method, in addition to general emulsion polymerization method.
Further, in a suspension polymerization method, it is possible to
retain an aqueous phase and a monomer phase individually, feed them
to a continuous dispersing device accurately and control the
particle diameter by the rotation speed of the dispersing device.
Further, in a continuous production method, it is possible to feed
a monomer phase into aqueous liquid having a dispersing ability
through small orifices having a diameter of several micrometers to
several tens of micrometers or a porous filter to control the
particle diameter. In the case of a core-shell-type graft polymer,
the reaction for the core and the shell may be one-stage or
multistage.
[0224] The elastomeric polymers are commercially and easily
available. Illustrative examples of those composed essentially of
butadiene rubber, acrylic rubber or butadiene-acrylic composite
rubber as a rubber component include Kane Ace B series (e.g. B-56)
of KANEKA CORPORATION, METABLEN C series (e.g. C-223A) and W series
(e.g. W-450A) of MITSUBISHI RAYON CO., LTD., PARALOID EXL series
(e.g. EXL-2602), HIA series (e.g. HIA-15), BTA series (e.g.
BTA-III) and KCA series of KUREHA CORPORATION, PARALOID EXL series
and KM series (e.g. KM-336P, KM-357P) of Rohm and Haas Company, and
UCL MODIFIER RESIN series of Ube Cyclon, Ltd. (UMG AXS RESIN series
of UMG ABS, Ltd.). Illustrative examples of those composed
essentially of acrylic-silicone composite rubber as a rubber
component include those which are commercially available from
MITSUBISHI RAYON CO., LTD. under trade names METABLEN 5-2001 and
SRK-200. The content of the impact improving agent is preferably
0.2 to 50 parts by weight, more preferably 1 to 30 parts by weight,
much more preferably 1.5 to 20 parts by weight, based on 100 parts
by weight of the thermoplastic resin (component A). With the
content within the above range, good impact resistance can be
provided to the composition while deterioration in rigidity is
inhibited.
<Others>
[0225] The resin composition of the present invention may contain
an antioxidant (such as a hindered phenol compound and
sulfur-containing antioxidant), ultraviolet absorber (such as a
benzotriazole, triazine or benzophenone-containing ultraviolet
absorber), light stabilizer (such as HALS), mold releasing agent
(such as a saturated fatty acid ester, unsaturated fatty acid
ester, polyolefin wax, fluorine compound, paraffin wax and
beeswax), flow modifier (such as a polycaprolactone), colorant
(such as carbon black, titanium dioxide, various organic dyes and
metallic pigments), light diffusing agent (such as acrylic
crosslinked particles and silicone crosslinked particles),
fluorescent brightener, light-storing pigment, fluorescent dye,
antistatic agent, inorganic and organic antimicrobial agents,
photocatalytic antifouling agent (such as titanium oxide fine
particles and zinc oxide fine particles), infrared absorber, and
photochromic agent ultraviolet absorber, as long as the effect of
the present invention is exerted. These various additives can be
used in known contents when contained in the thermoplastic
resin.
<Production Method of Resin Composition>
[0226] The resin composition can be produced by melt-kneading 100
parts by weight of the thermoplastic resin (component A) and 1 to
200 parts by weight of the polylactic acid (component B). The resin
composition is generally formed into pellets. The pellets are
preferably cut out of strands. For example, the pellets are
preferably in the shape of a cylinder having a diameter of 2 to 10
mm and a height of 2 to 15 mm, a sphere having a diameter of 3 to
10 mm or an oval sphere having a long diameter of 3 to 10 mm.
[0227] The component B is as have been described in the above
section of the resin composition. Therefore, the polylactic acid
(component B) to be melt-kneaded comprises the component B-1 and
the component B-4, and the weight ratio (component B-1/component
B-4) of the component B-1 to the component B-4 is 10/90 to
90/10.
[0228] The component B to be melt-kneaded shows a proportion
(R.sub.195 or higher) of melt peaks at 195.degree. C. or higher to
all melt peaks in a temperature rising process in measurement by a
differential scanning calorimeter (DSC) of at least 20%. The
R.sub.195 or higher is preferably at least 50%, more preferably at
least 80%, much more preferably at least 90%, particularly
preferably at least 95%.
[0229] The component B is preferably obtained by melt-kneading the
component B-1 and the component B-4 at 245 to 300.degree. C.
[0230] The thermoplastic resin (component A) is as have been
described above. The components C, D and E may be present at the
time of the melt-kneading. These components are as have been
described in the above section of the resin composition. The
melt-kneading is preferably carried out in the presence of 0.01 to
5 parts by weight of the crystal nucleating agent (component C)
based on 100 parts by weight of the component B. The component C is
preferably talc. The melt-kneading is preferably carried out in the
presence of 0.3 to 200 parts by weight of the inorganic filler
(component D) based on 100 parts by weight of the component A. The
melt-kneading is preferably carried out in the presence of 0.01 to
5 parts by weight of the terminal blocking agent (component E)
based on 100 parts by weight of the component B.
[0231] The components may be premixed before melt-kneaded.
Illustrative examples of means for premixing the components include
a NAUTA mixer, V-shaped blender, Henschel mixer, mechanochemical
device, and extrusion blender. In the premixing, granulation can be
carried out by means of an extrusion granulator, briquetting
machine or the like in some cases.
[0232] After premixed, the components are melt-kneaded by a
melt-kneader typified by a vented twin-screw extruder and
pelletized by equipment such as a pelletizer. Illustrative examples
of the melt-kneader further include a Banbury mixer, kneading roll,
and constant-heat agitator. The vented twin-screw extruder is
preferred. In addition, it is also possible to use a method of
feeding the above components and optionally other components to a
melt-kneader typified by a twin-screw extruder independently
without premixing them.
[0233] When a molded article is crushed and added as the
thermoplastic resin (component A), the crushed molded article has a
relatively high bulk density. Hence, it is preferably fed to an
extruder as a mixture with other components having a high bulk
density or fed to the extruder together with the components having
a high bulk density even when the components are fed independently.
By the production method, deterioration of the resin which is
caused by the recycled thermoplastic resin is further inhibited,
and a resin composition having more suitable color can be obtained.
Further, liquid raw materials are preferably fed separately by use
of a liquid feeder. Further, when the inorganic filler is added, it
may be fed through a first feed port at the base of a screw of the
extruder but is more preferably fed through a second feed port
located at the middle of the extruder by use of a side feeder.
<Molded Articles>
[0234] The resin composition of the present invention is generally
obtained as pellets, and molded articles can be produced by various
molding methods such as injection molding and extrusion using the
pellets as raw materials.
[0235] The R.sub.195 or higher of the molded article is preferably
at least 20%, more preferably at least 50%, much more preferably at
least 80%, further preferably at least 90%, particularly preferably
at least 95%.
[0236] For injection molding, a general cold runner method can be
used. A hot runner type molding method is also possible. For the
injection molding, injection compression molding, injection press
molding, gas assist injection molding, foam molding (including one
involving infusion of supercritical fluid), insert molding, in-mold
coating molding, insulated metal molding, rapid heating-cooling
molding, two-color molding, sandwich molding, ultrafast injection
molding and the like can be used. The advantages of these various
molding methods are already widely known.
[0237] By extrusion, molded articles such as an irregularly shaped
extruded article, sheet and film can be obtained. Further, to form
the sheet or film, inflation, calendaring, casting or the like can
also be employed. Further, a heat shrinkable tube can also be
molded by stretching.
[0238] The resin composition of the present invention can also be
molded into a hollow molded article by rotational molding, blow
molding or the like.
[0239] The molded articles of the present invention include an
automobile part, an electric/electronic part, an electrical
equipment exterior part, an office automation equipment exterior
part or an optical disk substrate. These molded articles can be
provided with other functions by being subjected to surface
modification. The surface modification includes vapor deposition
(e.g. physical vapor deposition, chemical vapor deposition),
plating (e.g. electroplating, electroless plating, hot-dip
plating), painting, coating, printing and the like for forming a
new layer on the surface layer of the resin molded article, and
general methods used for resin molded articles can be used.
(Automobile Parts)
[0240] Illustrative examples of the automobile parts of the present
invention include vehicle exterior parts, vehicle interior parts,
drive system mechanism parts, electronic control system
electronic/electric parts, electronic control system mechanism
parts, internal combustion engine associated parts, exhaust system
associated parts, various display components, and various lighting
equipment components. Specific examples thereof include a back
panel, fender, bumper, facia, door panel, side garnish, pillar,
radiator grill, side protector, side lacing, rear protector, rear
lacing, various spoilers, hood, roof panel, trunk lid, detachable
top, wind reflector, headlamp lens, mirror housing, outer door
handle, wiper parts, windshield washer nozzle, automotive antenna
parts, trim, lamp socket, lamp reflector, lamp housing,
instrumental panel, center console panel, deflector parts, meter
parts, airflow meter, actuator, ignition coil, distributor parts,
gas cap, fuse case, sensor housing, harness connector, various
switches, various relays, fuel tubing parts, engine locker cover,
engine ornament cover, timing belt cover, belt tensioner pulley,
chain guide, cam sprocket, generator bobbin, air cleaner case, air
intake duct, surge tank, fuel tank, intake manifold, fuel injection
parts, car navigation parts, car audio visual parts, and automobile
computer parts.
(Electric/Electronic Parts)
[0241] The electric/electronic parts of the present invention are
parts of electric/electronic equipments such as OA equipments,
household electric appliances, play equipments and special
industrial products.
[0242] Illustrative examples of parts of OA equipments and
household electric appliances include parts used for mutual
connection of electric wires, mutual connection of electric
insulated wires or connection of electric/electronic equipment and
an electric wire. Illustrative examples thereof include various
connectors, outlets, plugs, various switches for switching between
connection and disconnection of circuit, various electronic devices
for controlling the energization status of circuit, and various
electromechanical parts incorporated in other electric/electronic
equipments.
[0243] Specific examples thereof include connectors, relays,
condenser cases, switches, trans bobbins, terminal blocks, printed
circuit boards, cooling fans, valves, shield boards, various
buttons, various handles, various sensors, small motor parts,
various sockets, tuner parts, fuse cases, fuse holders, brush
holders, breaker parts, electromagnetic switches, deflection yokes,
flyback transformers, keycaps, rollers, bearings, and lamp
housings.
[0244] Specific examples of the OA equipments include desktop
personal computers, notebook-size personal computers, displays
(such as CRT, liquid crystal, plasma, projector and organic
electroluminescence), mice, and printers, copying machines,
scanners and fax machines (including their complex machines),
drives for recording media (such as CD, MD, DVD, next-generation
high density disks and hard disks), and readers for recording media
(such as IC cards, smart media and memory sticks).
[0245] Specific examples of the household electric appliances
include personal digital assistances (so-called "PDA"), cellular
phones, portable books (such as dictionaries), portable television
sets, optical cameras, digital cameras, parabolic antennas,
electric tools, VTR, irons, hair dryers, rice cookers, microwave
ovens, hotplates, audio equipments, lighting equipments,
refrigerators, air conditioners, air cleaners, negative ion
generators, typewriters, and clocks.
[0246] Specific examples of the play equipments include home video
game machines, arcade video game machines, pinball machines, and
slot machines. Specific examples of the special industrial products
include trays, carrier tapes, carrier cases and containers used for
carrying silicon wafers, integrated circuit chips, glass substrates
and the like.
(Electrical Equipment Exterior Parts)
[0247] Illustrative examples of the electrical equipment exterior
parts of the present invention include exterior parts for personal
computers such as desktop personal computers and notebook-size
personal computers.
(OA Equipment Exterior Parts)
[0248] Illustrative examples of the OA equipment exterior parts
include exterior parts for printers, copying machines, scanners and
fax machines (including their complex machines), displays (such as
CRT, liquid crystal, plasma, projector and organic
electroluminescence), and mice. Illustrative examples thereof
further include switch mechanism parts such as keys in keyboards
and various switches, and exterior parts for game machines (such as
home video game machines, arcade video game machines, pinball
machines and slot machines). Illustrative examples of the OA
equipments include personal digital assistances (so-called "PDA"),
cellular phones, portable books (such as dictionaries), portable
television sets, drives for recording media (such as CD, MD, DVD,
next-generation high density disks and hard disks), readers for
recording media (such as IC cards, smart media and memory sticks),
optical cameras, digital cameras, parabolic antennas, electric
tools, VTR, irons, hair dryers, rice cookers, microwave ovens, hot
plates, audio equipments, lighting equipments, refrigerators, air
conditioners, air cleaners, negative ion generators, typewriters,
and clocks.
(Optical Disk Substrates)
[0249] The optical disk substrate of the present invention is
obtained by injection-molding pellets of the resin composition. For
the injection molding, a hot runner type molding method as well as
a general cold runner method is possible. For the injection
molding, in addition to a general molding method, such an injection
molding method as injection compression molding, injection press
molding, gas assist injection molding, foam molding (including one
involving infusion of supercritical fluid), insert molding, in-mold
coating molding, insulated metal molding, rapid heating-cooling
molding, two-color molding, sandwich molding and ultrafast
injection molding can be used as appropriate according to purpose
to obtain the molded article. The advantages of these various
molding methods are already widely known.
[0250] For the injection molding, an injection molding machine
(including an injection compression molding machine) is used. As
this injection molding machine, one using a material that has low
adhesion to resins as a cylinder or screw and shows corrosion
resistance and abrasion resistance is preferably used from the
viewpoints of inhibition of production of carbide and improvement
of the reliability of the optical disk substrate, and an optical
disk substrate which is optically excellent can be obtained by use
of such an injection molding machine. The environment for the
molding process is preferably as clean as possible in view of the
object of the present invention. Further, it is important to fully
dry the material to be subjected to molding to remove water and to
be careful not to allow retention that causes decomposition of
molten resin to occur.
[0251] The shape of the optical disk substrate is generally
circular (disk-shaped). However, the shape and size thereof are not
particularly limited and are selected as appropriate according to
intended use. Further, a suitable thickness of the optical disk
substrate ranges from 0.3 to 1.2 mm. In the case of the optical
disk substrate in the present invention, bits or grooves are often
formed on one or both surfaces of the substrate by a stamper at the
time of its molding. However, such bits or grooves may not be
formed at the time of molding depending on intended use of the
optical disk substrate.
[0252] On the optical disk substrate of the present invention, a
reflective layer, a recording layer, a light transmissive layer
(transparent protective layer) and the like are laminated according
to intended use thereof, resulting in an optical disk as an
information recording medium.
[0253] The reflective layer can be formed by using metal elements
alone or in combination of two or more. As metal that forms the
reflective layer, Al or Au alone is preferably used, or an Al alloy
containing 0.5 to 10 wt %, particularly preferably 3.0 to 10 wt %
of Ti or an Al alloy containing 0.5 to 10 wt % of Cr is preferably
used. The reflective layer comprising the above metal can be formed
by a method such as an ion-beam sputtering method, DC (direct
current) sputtering method or RF sputtering method.
[0254] On the optical disk substrate in the present invention, a
recording layer (phase-change recording layer, dye recording layer
in the case of DVD-RAM, CD-R, DVD-R, DV-R or the like,
magnetooptical recording layer in the case of MO (magnetooptical
disk)) and a light transmissive layer are basically formed in
addition to the reflective layer to form an optical disk as an
information recording medium. As the phase-change recording layer,
chalcogen alone or a chalcogen compound is used, for example. More
specifically, Te or Se alone or a chalcogenite-containing material
such as Ge--Sb--Te, Ge--Te, In--Sb--Te, In--Se--Te--Ag, In--Se,
In--Se--Tl--Co, In--Sb--Se, Bi.sub.2Te.sub.3, BiSe,
Sb.sub.2Se.sub.3 or Sb.sub.2Te.sub.3 is used. Meanwhile, as the
magnetooptical recording layer, a perpendicular magnetization layer
having a magnetooptical property such as a Kerr Effect or a Faraday
effect, such as an amorphous alloy thin film such as Tb--Fe--Co, is
used.
[0255] A dielectric layer is preferably formed on both sides of the
recording layer to control optical properties and thermal
properties. As the dielectric layer, metal such as Al or Si or a
nitride, oxide or sulfide of metalloid element is used, for
example. Specific examples thereof include a mixture of ZnS and
SiO.sub.2, AlN, Si.sub.3N.sub.4, SiO.sub.2, Al.sub.2O.sub.3, ZnS
and M.sub.gF.sub.2.
[0256] The light transmissive layer is formed on the recording
layer, or on the dielectric layer when the dielectric layer exists.
This light transmissive layer becomes a transparent protective
layer for protecting the recording layer and pits or grooves on the
substrate. Illustrative examples of a material of this light
transmissive layer include transparent thermoplastic resins such as
an aromatic polycarbonate and amorphous polyolefin resin, and
various thermosetting (particularly, light curing) resins. A method
of forming the transparent protective layer is exemplified by a
method of laminating a transparent sheet such as a sheet made of a
thermoplastic resin such as an aromatic polycarbonate or amorphous
polyolefin resin on the recording layer (light curable resin is
suitable as an adhesive layer in this case). Another example of
such a method is a method of forming the protective layer by
coating an ultraviolet curable resin by a technique such as spin
coating and exposing the resin to ultraviolet radiation. Further,
particularly in a method using a transparent sheet, a protective
transparent layer having a high hardness property, antistatic
property and the like can be further formed on the surface thereof.
The thickness (including the thickness of the protective
transparent layer when it exists) of the light transmissive layer
is limited to a range of 3 to 200 .mu.m to keep somatic aberration
small. A thickness of about 100 .mu.m is particularly
preferred.
[0257] In many cases, recording/reproduction of information signal
is conducted on the optical disk by applying a ray of light from
the light transmissive layer side of the disk and allowing the
light to reach and be reflected on the recording layer or the like
through the light transmissive layer.
[0258] Further, the configuration of grooves or bits transferred
onto the optical disk substrate of the present invention, the
configuration of lamination formed on the substrate and the
configuration of the reflective layer (reflective film) or the
recording layer and the light transmissive layer are not
particularly limited. The grooves or pits may be formed on both
sides of the substrate, and the reflective layer or the recording
layer and the light transmissive layer may also be formed on both
sides of the substrate. Further, such a multilayer structure as
described above of the optical disk is widely known, and details
thereof are described in Japanese Patent Laid-Open Publication No.
11-7658, for example.
[0259] Next, specific examples of the multilayer structure of the
optical disk will be described in detail with reference to
drawings. It is needless to say that the drawings merely exemplify
typical structures of the optical disk and use of the optical disk
substrate of the present invention is not limited only to optical
disks having the illustrated structures.
[0260] FIGS. 6 to 9 each illustrate an example of the structure of
the optical disk as an optical recording medium and are a partial
view of a vertical cross section of the disk surface. An optical
disk 1 shown in FIG. 6 is formed by laminating, on an optical disk
substrate (1) that comprises the resin composition of the present
invention, a reflective layer (2), a recording layer (3) and a
light transmissive layer (4) sequentially. On the top surface of
the substrate (1), phase pits or grooves comprising a predetermined
convex and concave pattern such as fine projections and pits such
as pregrooves for recording data information, tracking servo
signals or the like are formed. Further, an optical disk 2 shown in
FIG. 7 has a multilayer structure in which, on an optical disk
substrate (1) that comprises the resin composition of the present
invention, a first reflective layer (5), a first recording layer
(6), an intermediate layer (7), a second reflective layer (8), a
second recording layer (9) and a light transmissive layer (4) are
laminated sequentially. Further, an optical disk 3 shown in FIG. 8
is formed by laminating, on the top surface of a substrate (1) that
comprises the polylactic acid resin composition and has pits or
grooves formed on both surfaces, a first reflective layer (5), a
first recording layer (6) and a light transmissive layer (4)
sequentially and laminating, on the under surface of the substrate
(1), a second reflective layer (8), a second recording layer (9)
and a light transmissive layer (4) sequentially. As materials of
the substrates, reflective layers, recording layers, light
transmissive layers and the like that constitute the optical disks
shown in FIGS. 6 to 8, materials having the same or similar
characteristics can be used.
[0261] Further, FIG. 9 shows an optical disk 4 that has a
multilayer structure in which a dielectric layer is formed on both
sides of a recording layer. In this disk 4, a reflective film (10),
a first dielectric layer (11), a phase-change-type recording layer
(12) and a second dielectric layer (13) are laminated on a
substrate (1), and the surface of the second dielectric layer (13)
is covered with a light transmissive layer (14). An example of the
thickness of each of the layers in the above layer constitution is
1.1 mm for the substrate, 60 nm for the reflective film, 19 nm for
the first dielectric layer, 24 nm for the phase-change-type
recording layer, 100 nm for the second dielectric layer and 100
.mu.m for the light transmissive layer.
[0262] In the present invention, as long as an optical disk has the
optical disk substrate comprising the polylactic acid (component B)
described in detail above, the optical disk is included within the
scope of the present invention regardless of the constitution and
number of layers laminated on the substrate.
[0263] The optical disk substrate of the present invention
preferably has an R.sub.195 or higher of at least 20%, more
preferably at least 50%, much more preferably at least 80%, further
preferably at least 95%. The larger the R.sub.195 or higher, the
higher the hydrolysis resistance of molded article becomes.
[0264] The melting point is preferably 195 to 250.degree. C., more
preferably 200 to 220.degree. C. The fusion enthalpy is preferably
at least 20 J/g, more preferably at least 30 J/g.
[0265] More specifically, it is preferred that the R.sub.195 or
higher be at least 30%, the melting point be 195 to 250.degree. C.
and the fusion enthalpy be at least 20 J/g.
[0266] Further, the optical disk substrate of the present invention
can be provided with other functions by being subjected to surface
modification. The surface modification includes vapor deposition
(e.g. physical vapor deposition, chemical vapor deposition),
plating (e.g. electroplating, electroless plating, hot-dip
plating), painting, coating, printing and the like for forming a
new layer on the surface layer of the resin molded article, and
general methods used for resin molded articles can be used.
Second Embodiment
Molded Articles
[0267] The present invention includes a molded article that
comprises a polylactic acid (component B) showing a proportion
(R.sub.195 or higher) of melt peaks at 195.degree. C. or higher to
all melt peaks in a temperature rising process in measurement by a
differential scanning calorimeter (DSC) of at least 20%.
(Component B)
[0268] The polylactic acid (component B) is as described in the
above section of the first embodiment. Thus, the component B
preferably comprises a polylactic acid (component B-1) that
comprises 90 to 100 mol % of L-lactic acid unit and 0 to 10 mol %
of D-lactic acid unit and/or units other than lactic acid and a
polylactic acid (component B-4) that comprises 90 to 100 mol % of
D-lactic acid unit and 0 to 10 mol % of L-lactic acid unit and/or
units other than lactic acid, and the weight ratio of the component
B-1 to the component B-4 (component B-1/component B-4) is
preferably within a range of 10/90 to 90/10.
[0269] The R.sub.195 or higher of the component B in the molded
article is preferably at least 70%, more preferably at least 80%,
much more preferably at least 90%, particularly preferably at least
95%. The molded article of the present invention has excellent heat
resistance, hydrolysis resistance and chemical resistance since it
comprises the polylactic acids having a high stereocomplex crystal
content. The molded article of the present invention preferably has
a molecular weight retention of at least 60%, more preferably at
least 80%, much more preferably at least 90%.
(Other Components)
[0270] The molded article may comprise a crystal nucleating agent
(component C), inorganic filler (component D), terminal blocking
agent (component E), flame retardant (component F), heat stabilizer
(component P) and other components. These are as described in the
above section of the first embodiment. Thus, the content of the
crystal nucleating agent (component C) is preferably 0.01 to 5
parts by weight based on 100 parts by weight of the component B.
The component C is preferably talc. The content of the inorganic
filler (component D) is preferably 0.3 to 200 parts by weight based
on 100 parts by weight of the component B. The content of the
terminal blocking agent (component E) is preferably 0.01 to 5 parts
by weight based on 100 parts by weight of the component B.
[0271] The shape of the molded article is preferably in a block
shape. That is, the molded article is preferably one having
effective length in three directions, rather than a fiber having
effective length in one direction or a film having effective length
in two directions.
[0272] The molded article in the second embodiment is also
preferably an automobile part, an electric/electronic part, an
electrical equipment exterior part, an OA equipment exterior part
or an optical disk substrate. Specific examples thereof are as
described in the above first embodiment.
[Production Method of Molded Article]
[0273] The present invention includes a method of producing a
molded article that comprises molding pellets comprising a
polylactic acid (component B) showing a proportion of melt peaks at
195.degree. C. or higher to all melt peaks in a temperature rising
process in measurement by a differential scanning calorimeter (DSC)
of at least 70%.
[0274] The component B in the pellets is as described in the
section of the resin composition of the first embodiment. The
R.sub.195 or higher of the component B in the pellets is preferably
at least 80%, more preferably at least 90%, particularly preferably
at least 95%.
[0275] The component B in the pellets preferably comprises a
polylactic acid (component B-1) that comprises 90 to 100 mol % of
L-lactic acid unit and 0 to 10 mol % of D-lactic acid unit and/or
units other than lactic acid and a polylactic acid (component B-4)
that comprises 90 to 100 mol % of D-lactic acid unit and 0 to 10
mol of L-lactic acid unit and/or units other than lactic acid, and
the weight ratio of the component B-1 to the component B-4
(component B-1/component B-4) is preferably within a range of 10/90
to 90/10.
[0276] The component B is preferably a polylactic acid obtained by
kneading the component B-1 and the component B-4 at 245 to
300.degree. C.
[0277] The polylactic acid (component B) having an R.sub.195 or
higher of at least 70% can be obtained by kneading the component
B-1 and the component B-4 at high temperatures that have been
unattempted. The kneading temperature is preferably 245 to
300.degree. C., more preferably 260 to 300.degree. C.
[0278] The pellets preferably contain 0.01 to 5 parts by weight of
crystal nucleating agent (component C) based on 100 parts by weight
of the component B. The component C is preferably talc. The pellets
preferably contain 0.3 to 200 parts by weight of inorganic filler
(component D) based on 100 parts by weight of the component B. The
pellets preferably contain 0.01 to 5 parts by weight of terminal
blocking agent (component E) based on 100 parts by weight of the
component B.
[0279] The pellets are preferably molded by injection molding,
extrusion, heat molding, blow molding or foam molding. Hereinafter,
an injection molded article, extruded article, heat molded article,
blow molded article and foam molded article will be described in
detail.
(Injection Molded Article)
[0280] An injection molded article is obtained by injection molding
the pellets containing the component B. The mold temperature is
preferably 80 to 130.degree. C., more preferably 100 to 120.degree.
C. Although a general polylactic acid (poly-L-lactic acid or
poly-D-lactic acid) is a crystalline polymer, its crystallization
rate is very slow, and it is very difficult to obtain a
crystallized molded article by injection molding even if a crystal
nucleating agent is added. As to a stereocomplex polylactic acid,
although the crystallization rate becomes faster than the
polylactic acid, a mold temperature of at least 140.degree. C. is
still required even if a crystal nucleating agent is added.
However, when the polylactic acid (component B) having an R.sub.195
or higher of at least 70% is used, a crystallized molded article
can be injection-molded in good condition at a mold temperature of
80 to 130.degree. C. that is a preferable range in terms of
productivity as well. When the mold temperature is higher than
130.degree. C., the cooling rate of molded article becomes slow, so
that a molding cycle becomes long disadvantageously. Meanwhile,
when the mold temperature is lower than 80.degree. C.,
solidification is very slow or a molded article is obtained in an
amorphous state disadvantageously.
[0281] For the injection molding, a hot runner method as well as a
general cold runner method can be employed. For the injection
molding, injection compression molding, injection press molding,
gas assist injection molding, foam molding (including one involving
infusion of supercritical fluid), insert molding, in-mold coating
molding, insulated metal molding, rapid heating-cooling molding,
two-color molding, sandwich molding and ultrafast injection molding
can be used. The advantages of these various molding methods are
already widely known.
[0282] A decrease in the R.sub.195 or higher of injection-molded
article is not observed, and the R.sub.195 or higher of the
injection-molded article is comparable to the R.sub.195 or higher
of the component B in the pellets. That is, the R.sub.195 or higher
of the injection-molded article is preferably at least 50%, more
preferably at least 80%, much more preferably at least 90%,
particularly preferably at least 95%. The larger the proportion of
melt peaks at 195.degree. C. or higher, the higher the hydrolysis
resistance of the molded article becomes.
[0283] The melting point of the injection-molded article is
preferably 195 to 250.degree. C., more preferably 200 to
220.degree. C. The fusion enthalpy is preferably at least 20 J/g,
more preferably at least 30 J/g.
[0284] The injection-molded article preferably shows a proportion
of melt peaks at 195.degree. C. or higher to all melt peaks derived
from the polylactic acid in a temperature rising process in
measurement by a differential scanning calorimeter (DSC) of at
least 70%, a melting point of 195 to 250.degree. C. and a fusion
enthalpy of at least 20 J/g.
(Extruded Article)
[0285] An extruded article is obtained by extruding a resin
obtained by melting the pellets at 200.degree. C. or higher. The
obtained extruded article is preferably heat-treated at
temperatures ranging from the crystallization temperature to the
melting point.
[0286] The extruded article is a molded article shaped by the shape
of the die of extruder by a melt process and is generally provided
in the shape of a sheet, film, rod, tube or the like. The sheet
refers to a sheet obtained by extruding a molten polymer into a
sheet from a die or the like and cooling it and may not have to be
particularly subjected to a stretching treatment. Meanwhile, the
film refers to a film obtained by stretching a sheet in a uniaxial
or biaxial direction sequentially or simultaneously to orient the
molecular chain.
[0287] The extruded article can be obtained by use of a general
known production method. For example, a film and a sheet can be
produced by, for example, supplying the polylactic acid as a raw
material into the hopper of single-screw or twin-screw extruder to
which a T die or I die is connected via a gear pump, melting the
raw material in the cylinder of the extruder, extruding it into a
sheet from the die and cooling the sheet by a casting roll. As to
the casting roll, the sheet is preferably closely attached to the
roll by use of an electrostatic adhesion device or air knife,
because nonuniformity in thickness and inclusion of air can be
prevented.
[0288] When the extruded article is a film, it can be produced by a
conventionally known film production method used for thermoplastic
resins. Illustrative examples of the method include an extrusion
method using a T die or I die, an inflation extrusion method using
a circular die, a flow casting method, a calendar molding method,
and a press molding method. The film is preferably molded by use of
any stretching method out of uniaxial stretching and biaxial
stretching using a roll or tenter. Illustrative examples of the
biaxial stretching include sequential biaxial stretching and
simultaneous biaxial stretching.
[0289] The R.sub.195 or higher of the extruded article is
preferably at least 20%, more preferably at least 50%, much more
preferably at least 80%, further preferably at least 90%,
particularly preferably at least 95%. The larger the R.sub.195 or
higher the higher the hydrolysis resistance of the extruded article
becomes.
[0290] The melting point is preferably 195 to 250.degree. C., more
preferably 200 to 220.degree. C. The fusion enthalpy is preferably
at least 10 J/g, more preferably at least 20 J/g, much more
preferably at least 30 J/g.
[0291] The extruded article preferably has an R.sub.195 or higher
of at least 20%, a melting point of 195 to 250.degree. C. and a
fusion enthalpy of at least 10 J/g.
[0292] The extruded article can be used not only as structural
members, packaging materials, industrial materials for
electric/electronic applications, automotive applications, and the
like but also as materials for heat molding.
[0293] The extruded article can be provided with other functions by
being subjected to surface modification. The surface modification
includes vapor deposition (e.g. physical vapor deposition, chemical
vapor deposition), plating (e.g. electroplating, electroless
plating, hot-dip plating), painting, coating, printing and the like
for forming a new layer on the surface layer of the resin molded
article, and general methods used for extruded articles such as a
sheet and a film can be used.
(Heat Molded Article)
[0294] A heat molded article is obtained by extruding a resin
obtained by melting the pellets at 200.degree. C. or higher into a
sheet from a slit die to obtain an extruded article and heating the
extruded article to the glass transition temperature or higher to
conduct heat molding. The obtained molded article is preferably
heat-treated at temperatures ranging from the crystallization
temperature to the melting point. The heat molded article is
produced by use of the sheet-shaped extruded article.
[0295] The sheet-shaped molded article can be prepared by known
equipment and method. That is, the sheet-shaped molded article is
obtained by a method comprising feeding the raw material into an
extruder, extruding the raw material through a slit die and cooling
and solidifying the extruded material on a casting drum to form a
sheet. As a method of feeding the raw material into the extruder,
any of the following methods, i.e. 1. a method comprising mixing
the components together, melt-kneading and extruding the components
by an extruder to prepare pellets and feeding the pellets into an
extruder equipped with a slit die to prepare a sheet, 2. a method
comprising preparing pellets of different compositions, mixing
predetermined amounts of the pellets together and feeding them into
an extruder for preparing a sheet to obtain the "sheet" and 3. a
method of charging one or more of the components directly into an
extruder for preparing a sheet, can be used. Further, it is also
possible to use flakes obtained by crushing a prepared sheet, a
prepared heat molded article and/or stripping debris produced upon
heat molding as the material or one of the components in sheet
formation in 1 and 2. It is preferable to add and mix some of the
components as fine powder into other components for the purpose of
uniform compounding of these components. The pellets and the
components are preferably dried before fed into an extruder.
[0296] Further, when the sheet is statically charged to be closely
attached to the cooling drum upon casting, a sheet having excellent
flatness can be obtained.
[0297] By heat-molding the thus obtained sheet of the present
invention, a variety of shapes can be formed and used for a variety
of applications.
[0298] The thus obtained sheet is subjected to heat molding after
preheated by an infrared heater, a hot-plate heater or hot air. As
a method for the heat molding, vacuum molding, pressure molding or
vacuum pressure molding using a negative mold, or a negative mold
and a positive mold, or a plug, can be employed, for example. Upon
molding, the negative mold, the positive mold and the plug can be
heated. In the present invention, all or some of processed articles
or heat molded articles of sheets may be bonded to each other or
other materials to further increase a degree of processing or may
be coated with various functional materials and used.
[0299] The heat molded article of the present invention preferably
has an R.sub.195 or higher of at least 20%, more preferably at
least 50%, much more preferably at least 80%, further preferably at
least 90%, particularly preferably at least 95%. The larger the
R.sub.195 or higher, the higher the hydrolysis resistance of the
heat molded article becomes.
[0300] The melting point is preferably 195 to 250.degree. C., more
preferably 200 to 220.degree. C. The fusion enthalpy is preferably
at least 10 J/g, more preferably at least 20 J/g, much more
preferably at least 30 J/g.
[0301] More specifically, it is preferred that the R.sub.195 or
higher be at least 20%, the melting point be 195 to 250.degree. C.
and the fusion enthalpy be at least 10 J/g.
[0302] The heat molded article of the present invention is useful
for packaging because it has excellent heat resistance and
hydrolysis resistance. For example, it is used for packaging
miscellaneous goods, toys, clothing, foods, optical products, OA
products, electric products, tools, machines, other industrial
products or their parts. However, the heat molded article of the
present invention is also used as a constituent part or a material
of the constituent part for electrical equipment, electronic
devices, OA equipment, electrically-operated machines and other
various devices. Further, the heat molded article can also be used
as a base material for various tapes or a base material for
products.
[0303] Further, the heat molded article of the present invention
can be provided with other functions by being subjected to surface
modification. The surface modification includes vapor deposition
(e.g. physical vapor deposition, chemical vapor deposition),
plating (e.g. electroplating, electroless plating, hot-dip
plating), painting, coating, printing and the like for forming a
new layer on the surface layer of the resin molded article, and
general methods used for extruded articles such as a sheet and a
film can be used.
(Blow Molded Article)
[0304] A blow molded article is obtained by molding a resin
obtained by melting the pellets at 200.degree. C. or higher to form
a parison, heating the parison to the glass transition temperature
or higher and then performing blow molding. The obtained molded
article is preferably heat-treated at temperatures ranging from the
crystallization temperature to the melting point.
[0305] The blow molded article refers to a hollow molded article
such as a bottle obtained by orientation-blowing a container or
preform obtained by injection molding or a hollow molded article
such as a bottle obtained by direct blowing. The
orientation-blowing and direct blowing can be carried out by known
equipment and a known method.
[0306] The blow molded article preferably has an R.sub.195 or
higher of at least 20%, more preferably at least 50%, much more
preferably at least 80%, further preferably at least 90%,
particularly preferably at least 95%. The larger the R.sub.195 or
higher/the higher the hydrolysis resistance of the blow molded
article becomes.
[0307] The melting point is preferably 195 to 250.degree. C., more
preferably 200 to 220.degree. C. The fusion enthalpy is preferably
at least 10 J/g, more preferably at least 20 J/g, much more
preferably at least 30 J/g.
[0308] The blow molded article preferably has an R.sub.195 or
higher of at least 20%, a melting point of 195 to 250.degree. C.
and a fusion enthalpy of at least 10 J/g.
[0309] The blow molded article can be used not only as a structural
member, a packaging material or the like but also as an industrial
material for electric/electronic applications, automotive
applications and the like.
[0310] Further, the blow molded article can be provided with other
functions by being subjected to surface modification. The surface
modification includes vapor deposition (e.g. physical vapor
deposition, chemical vapor deposition), plating (e.g.
electroplating, electroless plating, hot-dip plating), painting,
coating, printing and the like for forming a new layer on the
surface layer of the resin molded article, and general methods for
decorating molded articles can be used.
(Foam Molded Article)
[0311] A foam molded article is obtained by foam-molding a resin
obtained by melting the pellets at 160.degree. C. or higher. The
obtained molded article is preferably heat-treated at temperatures
ranging from the crystallization temperature to the melting
point.
[0312] As a method of forming foam in the foam molded article,
conventionally known various methods can be used. The foam molded
article can be produced by a method of forming a foam molded
article by including a thermally decomposable foaming agent in the
resin composition and thermally decomposing the foaming agent to
form foam. The thermally decomposable foaming agent is suitably
mixed with the polylactic acid as a raw material uniformly in
advance. Other methods include a method of mixing the foaming agent
directly with the pellets of the polylactic acid at the time of
production of the foam molded article and a method of mixing the
foaming agent in the form of a master agent.
[0313] Illustrative examples of the thermally decomposable foaming
agent include an azo compound, diazo compound, nitroso compound,
azi compound, tetrazole derivative, triazine derivative,
semicarbazide derivative, urea derivative, guanidine derivative,
carbonate, bicarbonate, and nitrite.
[0314] Further, the foam molded article of the present invention
can be produced by a method comprising a step of impregnating the
above polylactic acid with a volume expandable chemical substance
and a step of expanding the volume of the chemical substance within
the polylactic acid to form foam so as to obtain the foam molded
article. The gas pressure at the time of impregnation is preferably
at least 1 MPa, more preferably at least 10 MPa.
[0315] As the chemical substance, any organic or inorganic gas that
is in a gaseous state at normal temperature (23.degree. C.) and
normal pressure (atmospheric pressure) can be used. Illustrative
examples thereof include inorganic gases such as carbon dioxide
(carbon dioxide gas), nitrogen, oxygen, argon and water, and
organic gases such as chlorofluorocarbons, low-molecular-weight
hydrocarbons, chlorinated aliphatic hydrocarbons, brominated
aliphatic hydrocarbons, alcohols, benzene, toluene, xylene and
methylene. Specific examples of the low-molecular-weight
hydrocarbons include pentane, butane and hexane. An example of the
chlorinated aliphatic hydrocarbons is methyl chloride. An example
of the brominated aliphatic hydrocarbons is methyl bromide.
Further, various fluorinated aliphatic hydrocarbons (such as
tetrafluoroethylene) can also be used. Of the chemical substances,
carbon dioxide is suitable. Further, carbon dioxide can be rendered
supercritical at relatively low temperature and low pressure and is
easy to use in a more suitable aspect of the present invention. As
the chemical substance, one that is liquid at normal temperature
can also be used. Illustrative examples of such a chemical
substance include pentane, neopentane, hexane, heptane, methylene
chloride, trichloroethylene, and chlorofluorocarbons such as
CFC-11, CFC-12, CFC-113 and CFC-141b.
[0316] A method of impregnating the polylactic acid with the
chemical substance is not particularly limited. An example of such
a method is a method comprising enclosing the chemical substance in
a sealed autoclave as gas and pressurizing the chemical substance.
When the foam molded article is molded by a melt extruder, a method
of injecting gas as the chemical substance into the resin
composition in a molten state from a vent by use of a vented screw
extruder can be used. In that case, impregnation with the chemical
substance is conducted with the resin composition in a molten state
being pressure-sealed.
[0317] Another suitable aspect of producing the foam molded article
of the present invention is a method of producing the foam molded
article by a method comprising a step of impregnating the resin
composition with a volume expandable chemical substance in the
cylinder of injection molding machine under high pressure, a step
of filling the resin composition impregnated with the chemical
substance in the mold cavity of the injection molding machine and a
step of expanding the volume of the chemical substance within the
composition without substantially expanding the cavity to form foam
so as to obtain the foam molded article. By the method, a foam
molded article that has a high degree of flexibility in shape, low
warpage attributed to filling of resin into a mold under low
pressure, few sinks even when a change in thickness is large and
excellent lightweight and rigidity and that is suitable as a
structural material is obtained.
[0318] "Without substantially expanding the cavity" indicates that
the volume of the cavity is kept unchanged from completion of
filling of the resin. However, the volume may be slightly expanded
as long as the size of the product is secured. The degree of
expansion of the cavity is suitably within 1.05 times, preferably
within 1.01 times, particularly preferably 1 time of the cavity
volume at the time of completion of filling of the resin. The
impregnated chemical substance expands in volume and forms foam
such that it compensates the volume shrinkage which occurs with
cooling and solidification of the resin. As a result, a foam molded
article that matches target size and shape is obtained without
sinks in a thick portion and warpage.
[0319] Further, for production of the foam molded article of the
present invention, a method of impregnating the resin composition
with the chemical substance that is in a gaseous state at normal
temperature and normal pressure in a supercritical state is more
preferred. With the method, the effect of the present invention is
exerted more prominently in that a fine and uniform foamed cell is
obtained.
[0320] The foam molded article of the present invention preferably
has an R.sub.195 or higher of at least 20%, more preferably at
least 50%, much more preferably at least 80%, further preferably at
least 90%, particularly preferably at least 95%. The larger the
proportion of melt peaks at 195.degree. C. or higher, the higher
the hydrolysis resistance of the foam molded article becomes.
[0321] The melting point is preferably 195 to 250.degree. C., more
preferably 200 to 220.degree. C. The fusion enthalpy is preferably
at least 10 J/g, more preferably at least 20 J/g, much more
preferably at least 30 J/g.
[0322] More specifically, it is preferred that the R.sub.195 or
higher be at least 20%, the melting point be 195 to 250.degree. C.
and the fusion enthalpy be at least 10 J/g.
[0323] The foam molded article of the present invention can be used
not only as a structural member, a packaging material, a container,
a cushioning material or the like but also as an industrial
material for electric/electronic applications, automotive
applications and the like.
[0324] Further, the foam molded article of the present invention
can be provided with other functions by being subjected to surface
modification. The surface modification includes vapor deposition
(e.g. physical vapor deposition, chemical vapor deposition),
plating (e.g. electroplating, electroless plating, hot-dip
plating), painting, coating, printing and the like for forming a
new layer on the surface layer of the resin molded article, and
general methods for decorating molded articles can be used.
EXAMPLES
[0325] Hereinafter, the present invention will be further described
with reference to Examples. However, the present invention shall
not be limited to these Examples.
(Component B)
[0326] Polylactic acids were produced in the following manners.
Physical properties were determined in the following manners.
(1) Reduced Viscosity: 0.12 g of polylactic acid was dissolved in
10 ml of tetrachloroethane/phenol (volume ratio: 1/1), and reduced
viscosity (ml/g) at 35.degree. C. was measured. (2) weight Average
Molecular Weight: The weight average molecular weight (Mw) of
polylactic acid was determined by GPC (column temperature:
40.degree. C., chloroform), through comparison with a polystyrene
standard sample. (3) Crystallization Point and Melting Point: A
polylactic acid was measured by use of DSC in a nitrogen atmosphere
at a temperature elevation rate of 20.degree. C./min to determine
its crystallization point (Tc) and melting point (Tm).
Production Example 1
Production of Component B-3
[0327] 50 parts by weight of L-lactide (Musashino Chemical
Laboratory, Ltd.) was charged into a polymerization tank, the
inside of the system was substituted with nitrogen, 0.05 parts by
weight of stearyl alcohol and 25.times.10.sup.-3 parts by weight of
tin octylate as a catalyst were added, and polymerization was
conducted at 190.degree. C. for 2 hours to obtain a component B-3.
The obtained component B-3 had a reduced viscosity of 1.48 (ml/g),
a weight average molecular weight of 110,000, a melting point (Tm)
of 158.degree. C. and a crystallization point (Tc) of 117.degree.
C.
Production Example 2
Production of Component B-6
[0328] 50 parts by weight of D-lactide (Musashino Chemical
Laboratory, Ltd.) was charged into a polymerization tank, the
inside of the system was substituted with nitrogen, 0.05 parts by
weight of stearyl alcohol and 25.times.10.sup.-3 parts by weight of
tin octylate as a catalyst were added, and polymerization was
conducted at 190.degree. C. for 2 hours to obtain a component B-6.
The obtained component B-6 had a reduced viscosity of 1.95 (ml/g),
a weight average molecular weight of 110,000, a melting point (Tm)
of 158.degree. C. and a crystallization point (Tc) of 121.degree.
C.
Production Example 3
Production of Component B-2
[0329] 48.75 parts by weight of L-lactide (product of Musashino
Chemical Laboratory, Ltd.) and 1.25 parts by weight of D-lactide
(product of Musashino Chemical Laboratory, Ltd.) were charged into
a polymerization tank, the inside of the system was substituted
with nitrogen, 0.05 parts by weight of stearyl alcohol and
25.times.10.sup.-3 parts by weight of tin octylate as a catalyst
were added, and polymerization was carried out at 190.degree. C.
for 2 hours to produce a polymer. This polymer was washed with an
acetone solution of 7% 5N hydrochloric acid to remove the catalyst.
Thereby, a component B-2 was obtained. The obtained component B-2
had a reduced viscosity of 1.47 (ml/g), a weight average molecular
weight of 100,000, a melting point (Tm) of 159.degree. C. and a
crystallization point (Tc) of 120.degree. C.
Production Example 4
Production of Component B-5
[0330] 1.25 parts by weight of L-lactide (product of Musashino
Chemical Laboratory, Ltd.) and 48.75 parts by weight of D-lactide
(product of Musashino Chemical Laboratory, Ltd.) were charged into
a polymerization tank, the inside of the system was substituted
with nitrogen, 0.05 parts by weight of stearyl alcohol and
25.times.10.sup.-3 parts by weight of tin octylate as a catalyst
were added, and polymerization was carried out at 190.degree. C.
for 2 hours to produce a polymer. This polymer was washed with an
acetone solution of 7% 5N hydrochloric acid to remove the catalyst.
Thereby, a component B-5 was obtained. The obtained component B-5
had a reduced viscosity of 1.76 (ml/g), a weight average molecular
weight of 120,000, a melting point (Tm) of 156.degree. C. and a
crystallization point (Tc) of 120.degree. C.
Production Example 5
Production of Polylactic Acid 1
[0331] 100 parts by weight of the component B-3 obtained in
Production Example 1 and 100 parts by weight of the component B-6
obtained in Production Example 2 were fed to a 30-mm-.phi. vented
twin-screw extruder [TEX30XSST of Japan Steel Works, Ltd.],
melt-extruded at a cylinder temperature of 280.degree. C., a screw
rotation speed of 150 rpm, a discharge rate of 15 kg/h and a vent
pressure reduction degree of 3 kPa and pelletized to obtain a
polylactic acid 1.
Production Example 6
Production of Polylactic Acid 2
[0332] 100 parts by weight of the component B-2 obtained in
Production Example 3 and 100 parts by weight of the component B-5
obtained in Production Example 4 were fed to a 30-mm-.phi. vented
twin-screw extruder [TEX30XSST of Japan Steel Works, Ltd.],
melt-extruded at a cylinder temperature of 280.degree. C., a screw
rotation speed of 150 rpm, a discharge rate of 15 kg/h and a vent
pressure reduction degree of 3 kPa and pelletized to obtain a
polylactic acid 2.
Production Example 7
Production of Polylactic Acid 3
[0333] 100 parts by weight of the component B-2 obtained in
Production Example 3, 100 parts by weight of the component B-5
obtained in Production Example 4 and 1 part by weight of
carbodiimide compound (CARBODILITE HMV-8CA of NISSHINBO INDUSTRIES,
INC.) were fed to a 30-mm-.phi. vented twin-screw extruder
[TEX30XSST of Japan Steel Works, Ltd.], melt-extruded at a cylinder
temperature of 280.degree. C., a screw rotation speed of 150 rpm, a
discharge rate of 15 kg/h and a vent pressure reduction degree of 3
kPa and pelletized to obtain a polylactic acid 3.
Production Example 8
Production of Polylactic Acid 4
[0334] 100 parts by weight of the component B-2 obtained in
Production Example 3 and 100 parts by weight of the component B-5
obtained in Production Example 4 were fed to a 30-mm-.phi. vented
twin-screw extruder [TEX30XSST of Japan Steel Works, Ltd.],
melt-extruded at a cylinder temperature of 230.degree. C., a screw
rotation speed of 150 rpm, a discharge rate of 10 kg/h and a vent
pressure reduction degree of 3 kPa and pelletized to obtain a
polylactic acid 4.
Production Example 9
Production of Polylactic Acid 5
[0335] A polylactic acid 5 was obtained in the same manner as in
Production Example 8 except that the cylinder temperature was
changed to 260.degree. C.
(Component A)
[0336] A-1: aromatic polycarbonate resin powder (Panlite L-1250WP
of TEIJIN CHEMICALS LTD., viscosity average molecular weight:
23,900)
(Component C)
[0337] C-1: talc (HiTalc Premium HTP ultra 5C of TOMOE Engineering
Co., Ltd.)
(Component D)
[0338] D-1: glass fibers (ECS-03T-511 of Nippon Electric Glass Co.,
Ltd., chopped strand having an average diameter of 13 .mu.m and a
cut length of 3 mm) D-2: talc (HST-0.8 of Hayashi-Kasei Co.,
Ltd.)
(Component E)
[0339] E: carbodiimide compound (Carbodilite HMV-8CA of Nisshinbo
Industries, Inc.)
(Component F)
[0340] F-1: phosphoric ester flame retardant (PX-200 of Daihachi
Chemical Industry Co., Ltd.) F-2: polytetrafluoroethylene having a
fibril forming ability (POLYFLON MPA FA-500 of DAIKIN INDUSTRIES,
Ltd.) F-3: phosphoric ester flame retardant (CR-741 of Daihachi
Chemical Industry Co., Ltd.)
(Component P)
[0341] P-1: distearyl pentaerythritol diphosphite (ADKSTAB PEP-8 of
ADEKA CORPORATION)
Examples 1 to 12 and Comparative Example 1
Pellets
[0342] Aromatic polycarbonate resins (component A), polylactic
acids (component B), crystal nucleating agents (component C),
inorganic fillers (component D), phosphorus stabilizers (component
P), phosphoric ester flame retardants (component F) and the like
were fed to a 30-mm-.phi. vented twin-screw extruder [TEX30XSST of
Japan Steel Works, Ltd.] according to compositions shown in Table
1, melt-extruded at a cylinder temperature of 260.degree. C., a
screw rotation speed of 150 rpm, a discharge rate of 20 kg/h and a
vent pressure reduction degree of 3 kPa, and pelletized.
[0343] As for screw configuration, a first kneading zone
(comprising two forward kneading disks, one forward rotor, one
backward rotor and one backward kneading disk) was provided before
a side feeder position, and a second kneading zone (comprising one
forward rotor and one backward rotor) was provided after the side
feeder position.
[0344] Productions of the pellets in the above Examples and
Comparative Example were carried out in the following manners
(descriptions of the components are given by use of the above
symbols).
(i) Examples 1 to 3, 6, 7 and 10 and Comparative Example 1
[0345] All components were mixed uniformly by use of a tumbler to
prepare a premixture, and the mixture was fed from a first feed
port of the extruder. Further, PTFE was premixed into PC-1
uniformly to a concentration of 2.5 wt %, and the mixture was fed
into the tumbler.
(ii) Examples 4, 5, 8, 9, 11 and 12
[0346] The inorganic filler D-1 was fed from a second feed port by
use of a side feeder, and the remaining components were premixed by
use of a tumbler and fed from the first feed port. Further, PTFE
was premixed into A-1 uniformly to a concentration of 2.5 wt %, and
the mixture was fed into the tumbler.
(Test Pieces)
[0347] The obtained pellets were dried by a hot-air
circulation-type dryer at 100.degree. C. for 5 hours. The dried
pellets were molded into test pieces of various sizes by an
injection molding machine (IS-150EN of Toshiba Machine Co., Ltd.)
at a cylinder temperature of 240.degree. C., a mold temperature of
80.degree. C. and a molding cycle of 40 seconds. By use of these
test pieces, a proportion (R.sub.195 or higher) of melt peaks at
195.degree. C. or higher, flexural strength, flexural modulus,
deflection temperature under load, combustibility and hydrolysis
resistance were evaluated. The results are shown in Table 1. The
physical properties were measured in the following manners. The
R.sub.195 or higher of notebook-size personal computer housing and
office automation equipment exterior part were evaluated by cutting
test pieces out of molded articles.
(1) Proportion (R.sub.195 or Higher) of Melt Peaks at 195.degree.
C. or Higher:
[0348] A measurement was made by use of DSC in a nitrogen
atmosphere at a temperature elevation rate of 20.degree. C./min,
and a proportion (%) of melt peaks at 195.degree. C. or higher was
calculated from a melt peak area at 195.degree. C. or higher (high
temperatures) and a melt peak area at 140 to 180.degree. C. (low
temperatures) in accordance with the following formula.
R.sub.195 or higher (%)=A.sub.195 or higher/(A.sub.195 or
higher+A.sub.140 to 180).times.100
R.sub.195 or higher: proportion of melt peaks at 195.degree. C. or
higher A.sub.195 or higher: melt peak area at 195.degree. C. or
higher A.sub.140 to 180: melt peak area at 140 to 180.degree.
C.
(2) Flexural Strength:
[0349] Flexural strength was measured in accordance with ISO178 by
use of a test piece having a length of 80 mm, a width of 10 mm and
a thickness of 4 mm.
(3) Flexural Modulus:
[0350] Flexural modulus was measured in accordance with ISO0178 by
use of a test piece having a length of 80 mm, a width of 10 mm and
a thickness of 4 mm.
(4) Deflection Temperature under Load:
[0351] Deflection temperature under load was measured in accordance
with 15075-1 and -2 under a load of 1.80 MPa.
(5) Combustibility:
[0352] The combustibility of test piece having a thickness of 1.6
mm was evaluated in accordance with a method (UL94) provided by
Underwriter Laboratory in the U.S. (only those containing a
phosphoric ester flame retardant were evaluated).
(6) Hydrolysis Resistance:
[0353] The viscosity average molecular weight of test piece after
it was treated in a pressure cooker tester at 120.degree. C. and a
relative humidity of 100% for 8 hours was measured, and retention
between before and after the treatment was determined. The
viscosity average molecular weight is a viscosity average molecular
weight resulting from converting a methylene chloride soluble part
in the test piece into an aromatic polycarbonate resin. The
viscosity average molecular weight was determined according to the
following procedure.
(Preparation of Methylene Chloride Soluble Solid Part (Sample))
[0354] A test piece was mixed with 20 to 30 times by weight of
methylene chloride to dissolve a methylene chloride soluble part in
the test piece. A methylene chloride insoluble part was separated
by sellite filtration, methylene chloride was removed from the
resulting solution, and the remaining solid part was fully dried to
obtain a methylene chloride soluble solid part.
(Procedure for Determining Viscosity Average Molecular Weight)
[0355] A sample solution prepared by dissolving 0.7 g of the
methylene chloride soluble solid part in 100 ml of methylene
chloride and a methylene chloride solvent were measured for time of
flow in an Ostwald viscometer at 20.degree. C., and specific
viscosity (.eta..sub.SP) was calculated in accordance with the
following formula.
Specific Viscosity (.eta..sub.SP)=(t-t.sub.0)/t.sub.0
[t.sub.0 is time of flow of methylene chloride in seconds, and t is
time of flow of sample solution in seconds.] Limiting viscosity
[.eta.] was calculated from the determined specific viscosity
(.eta..sub.SP) in accordance with the following formula.
.eta..sub.SP/c=[.eta.]+0.45.times.[.eta.].sup.2c
[0356] M determined from the limiting viscosity [.eta.] by use of
the following formula was taken as viscosity average molecular
weight. Further, as K and a in the following formula that are
Mark-Houwink constants, values that are generally determined for a
methylene chloride solution of a polycarbonate resin at 20.degree.
C. were used.
[.eta.]=KM.sup.a(K=1.23.times.10.sup.-4,a=0.83)
(7) Chemical Resistance
(i) Test 2 . . . . Automobile Part
[0357] The obtained pellets were dried by a hot-air
circulation-type dryer at 100.degree. C. for 5 hours. Thereafter,
the pellets were molded into a test piece for an automobile part
complying with ISO527-1 and -2 and having a thickness of 3.2 mm by
an injection molding machine (IS-150EN of Toshiba Machine Co.,
Ltd.) at a cylinder temperature of 240.degree. C., a mold
temperature of 80.degree. C. and a molding cycle of 40 seconds.
With a distortion of 0.5% applied, the test piece was immersed in
Esso regular gasoline at room temperature for 12 hours.
Subsequently, the appearance of the test piece was observed
visually and rated based on the occurrence of cracking. An overview
of attachment of the test piece is shown in FIG. 1.
.largecircle.: No cracking occurred. x: Cracking occurred.
[0358] The distortion (.di-elect cons.=0.005) is a value calculated
from a formula .di-elect cons.=(6hy)/L.sup.2 when the span between
two points at both ends out of three points is L (100 mm), the
thickness of the test piece is h (3.2 mm) and height to which the
test piece was lifted from a horizontal state is y (mm).
(ii) Test 3 . . . . Connector
[0359] The obtained pellets were dried by a hot-air
circulation-type dryer at 100.degree. C. for 5 hours. Thereafter,
the pellets were molded into a connector for 24 (12.times.2) pins
having an external size of 20 mm.times.5 mm.times.5 mm by use of an
injection molding machine (N40A of Japan Steel Works, Ltd.) at a
cylinder temperature of 250.degree. C. and a mold temperature of
90.degree. C. After the obtained connector was immersed in methanol
at room temperature for one week, its surface condition was
observed and rated based on the following criteria.
.circleincircle.: No change is observed. .largecircle.: Slight
surface roughness of acceptable degree as a product is observed. x:
Surface roughness of unacceptable degree as a product is observed.
(iii) Test 4 . . . . Notebook-Size Personal Computer Housing
[0360] The obtained pellets were dried by a hot-air
circulation-type dryer at 100.degree. C. for 5 hours. Then, the
pellets were molded into a notebook-size personal computer housing
shown in FIGS. 2 to 4 by use of an injection molding machine having
a cylinder inner diameter of 50 mm .phi. (ULTRA220-NIVA of Sumitomo
Heavy Industries, Ltd.) at a cylinder temperature of 250.degree. C.
and a mold temperature of 80.degree. C. After the notebook-size
personal computer housing was immersed in methanol at room
temperature for one week, its surface condition was observed and
rated based on the following criteria.
.circleincircle.: No change is observed. .largecircle.: Slight
surface roughness of acceptable degree as a product is observed. x:
Surface roughness of unacceptable degree as a product is
observed.
(iv) Test 5 . . . . Office Automation Equipment Exterior Part
[0361] The obtained pellets were dried by a hot-air
circulation-type dryer at 100.degree. C. for 5 hours. Then, the
pellets were molded into an office automation equipment exterior
part shown in FIG. 5 by use of an injection molding machine
(J1300E-C5 of Japan Steel Works, Ltd.) at a cylinder temperature of
250.degree. C. and a mold temperature of 80.degree. C. After the
office automation equipment exterior part was immersed in methanol
at room temperature for one week, its surface condition was
observed and rated based on the following criteria.
.circleincircle.: No change is observed. .largecircle.: Slight
surface roughness of acceptable degree as a product is observed. x:
Surface roughness of unacceptable degree as a product is
observed.
TABLE-US-00002 TABLE 1 C. Ex. 1 Ex. 1 Ex. 2 Ex. 3 Ex. 4 Ex. 5
Component A A-1 100 100 100 100 100 100 Component B B-3 20 -- -- --
-- -- B-6 -- -- -- -- -- -- B-2 -- -- -- -- -- -- B-5 -- -- -- --
-- -- Polylactic Acid 1 -- 20 20 -- -- -- Polylactic Acid 2 -- --
-- 20 20 20 Components B + E Polylactic Acid 3 -- -- -- -- -- --
Component C C-1 -- -- 0.5 -- -- 0.5 Component D D-1 -- -- -- -- 50
50 D-2 -- -- -- -- -- -- Others F-1 -- -- -- -- -- -- F-2 -- -- --
-- -- -- F-3 -- -- -- -- -- -- P-1 0.1 0.1 0.1 0.1 0.1 0.1
R.sub.195 or higher of Pellets (%) 0 32 51 98 98 98 Test Piece
R.sub.195 or higher (%) 0 35 47 96 96 97 Flexural Strength (MPa) 97
96 96 97 165 167 Flexural Modulus (MPa) 2300 2300 2300 2300 7300
7300 Deflection Temperature under Load 116 118 118 119 140 140
(.degree. C.) Combustibility (UL94) -- -- -- -- -- -- Hydrolysis
Resistance Before Test 29400 28500 28600 28100 28000 27800
(Viscosity Average After Test 5300 10000 10900 18000 19300 19500
Molecular Weight) Retention (%) 18 35 38 64 69 70 Chemical Test 2
(Automobile Part) X .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. Resistance Test 3 (Connector) X
.largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. Test 4 (Notebook-size Computer X .largecircle.
.largecircle. .largecircle. .largecircle. .largecircle. Housing)
Test 5 (OA Equipment Exterior Part) X .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle. Ex. 6 Ex. 7 Ex. 8 Ex. 9
Ex. 10 Ex. 11 Ex. 12 Component A A-1 100 100 100 100 100 100 100
Component B B-3 -- -- -- -- -- -- -- B-6 -- -- -- -- -- -- -- B-2
-- -- -- -- -- -- -- B-5 -- -- -- -- -- -- -- Polylactic Acid 1 --
-- -- -- -- -- -- Polylactic Acid 2 -- -- -- -- 40 -- -- Components
B + E Polylactic Acid 3 20 20 20 30 -- 100 180 Component C C-1 --
-- 0.5 0.5 0.5 0.5 0.5 Component D D-1 -- -- 50 10 -- 50 50 D-2 --
10 -- -- 10 -- -- Others F-1 -- 15 15 15 -- -- -- F-2 -- 0.5 0.5
0.5 0.5 -- -- F-3 -- -- -- -- 15 -- -- P-1 0.1 0.1 0.1 0.1 0.1 0.1
0.1 R.sub.195 or higher of Pellets (%) 99 98 99 97 96 95 96 Test
Piece R.sub.195 or higher (%) 97 96 98 98 95 96 94 Flexural
Strength (MPa) 97 85 160 130 135 162 180 Flexural Modulus (MPa)
2300 3100 7400 4300 4400 7500 7900 Deflection Temperature under
Load 117 84 125 93 81 140 145 (.degree. C.) Combustibility (UL94)
-- V-0 V-0 V-2 V-2 -- -- Hydrolysis Resistance Before Test 27900
27700 27500 26900 27200 27800 28200 (Viscosity Average After Test
22300 23000 23100 22100 21500 23600 24000 Molecular Weight)
Retention (%) 80 83 84 82 79 85 85 Chemical Test 1 (Automobile
Part) .largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle. Resistance Test 2
(Connector) .largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle. Test 3 (Notebook-size
Computer .largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle. Housing) Test 4 (OA
Equipment Exterior Part) .largecircle. .largecircle. .largecircle.
.largecircle. .largecircle. .largecircle. .largecircle. C. Ex.:
Comparative Example, Ex.: Example
[0362] As is clear from Table 1, the resin compositions of the
present invention show high R.sub.195 or higher and a high
stereocomplex crystal content and are, as a result, excellent in
hydrolysis resistance. It can be seen that hydrolysis resistance is
further improved by containing the terminal blocking agent
(component E). Further, the molded articles of the present
invention show excellent hydrolysis resistance and chemical
resistance. Further, it can be seen that mechanical strength is
improved by containing the inorganic filler (component D). Further,
it can be seen that flame retardancy is improved by containing the
flame retardant (component F).
Example 13
[0363] 100 parts by weight of the polylactic acid 3 produced in
Production Example 7, 100 parts by weight of polyethylene
terephthalate resin (TR-8550 of TEIJIN CHEMICALS LTD.), 0.1 parts
by weight of bis(2,4-di-t-butylphenyl)pentaerythritol diphosphite
(ADKSTAB PEP-24G of ADEKA CORPORATION) and 0.05 parts by weight of
trimethyl phosphate (TMP of Daihachi Chemical Industry Co., Ltd.)
were fed to a 30-mm-.phi. vented twin-screw extruder (TEX30XSST of
Japan Steel Works, Ltd.), melt-extruded at a cylinder temperature
of 250.degree. C., a screw rotation speed of 150 rpm, a discharge
rate of 20 kg/h and a vent pressure reduction degree of 3 kPa, and
pelletized. The obtained pellets were dried by a hot-air
circulation-type dryer at 100.degree. C. for 5 hours. After dried,
the pellets were injection-molded by an injection molding machine
(IS-150EN of Toshiba Machine Co., Ltd.) at a cylinder temperature
of 250.degree. C., a mold temperature of 110.degree. C. and a
molding cycle of 180 seconds to obtain a molded piece.
Example 14
[0364] 100 parts by weight of the polylactic acid 3 produced in
Production Example 7, 100 parts by weight of polybutylene
terephthalate resin (DURANEX 700FP of WinTech Polymer Ltd.), 0.1
parts by weight of bis(2,4-di-t-butylphenyl)pentaerythritol
diphosphite (ADKSTAB PEP-24G of ADEKA CORPORATION) and 0.1 parts by
weight of hindered phenol antioxidant (IRGANOX 1076 of Ciba
Specialty Chemicals) were fed to a 30-mm-.phi. vented twin-screw
extruder (TEX30XSST of Japan Steel Works, Ltd.), melt-extruded at a
cylinder temperature of 250.degree. C., a screw rotation speed of
150 rpm, a discharge rate of 20 kg/h and a vent pressure reduction
degree of 3 kPa, and pelletized. The obtained pellets were dried by
a hot-air circulation-type dryer at 100.degree. C. for 5 hours.
After dried, the pellets were injection-molded by an injection
molding machine (IS-150EN of Toshiba Machine Co., Ltd.) at a
cylinder temperature of 250.degree. C., a mold temperature of
110.degree. C. and a molding cycle of 180 seconds to obtain a
molded piece.
Example 15
[0365] 100 parts by weight of the polylactic acid 3 produced in
Production Example 7, 100 parts by weight of polyethylene
naphthalate resin (TN-8065 of TEIJIN CHEMICALS LTD.), 0.1 parts by
weight of bis(2,6-di-t-butyl-4-methylphenyl)pentaerythritol
diphosphite (ADKSTAB PEP-36 of ADEKA CORPORATION) and 0.1 parts by
weight of hindered phenol antioxidant (IRGANOX 1076 of Ciba
Specialty Chemicals) were fed to a 30-mm-.phi. vented twin-screw
extruder (TEX30XSST of Japan Steel Works, Ltd.), melt-extruded at a
cylinder temperature of 270.degree. C., a screw rotation speed of
150 rpm, a discharge rate of 20 kg/h and a vent pressure reduction
degree of 3 kPa, and pelletized. The obtained pellets were dried by
a hot-air circulation-type dryer at 100.degree. C. for 5 hours.
After dried, the pellets were injection-molded by an injection
molding machine (IS-150EN of Toshiba Machine Co., Ltd.) at a
cylinder temperature of 270.degree. C., a mold temperature of
110.degree. C. and a molding cycle of 180 seconds to obtain a
molded piece.
Example 16
[0366] 100 parts by weight of the polylactic acid 3 produced in
Production Example 7, 100 parts by weight of polybutylene
naphthalate resin (TQB-OT of TEIJIN CHEMICALS LTD.), 0.1 parts by
weight of bis(2,6-di-t-butyl-4-methylphenyl) pentaerythritol
diphosphite (ADKSTAB PEP-36 of ADEKA CORPORATION) and 0.1 parts by
weight of hindered phenol antioxidant (IRGANOX 1076 of Ciba
Specialty Chemicals) were fed to a 30-mm-.phi. vented twin-screw
extruder (TEX30XSST of Japan Steel Works, Ltd.), melt-extruded at a
cylinder temperature of 270.degree. C., a screw rotation speed of
150 rpm, a discharge rate of 20 kg/h and a vent pressure reduction
degree of 3 kPa, and pelletized. The obtained pellets were dried by
a hot-air circulation-type dryer at 100.degree. C. for 5 hours.
After dried, the pellets were injection-molded by an injection
molding machine (IS-150EN of Toshiba Machine Co., Ltd.) at a
cylinder temperature of 270.degree. C., a mold temperature of
110.degree. C. and a molding cycle of 180 seconds to obtain a
molded piece.
Example 17
[0367] 100 parts by weight of the polylactic acid 3 produced in
Production Example 7, 100 parts by weight of ABS resin (SANTAC
UT-61 of NIPPON A&L INC.), 0.1 parts by weight of distearyl
pentaerythritol diphosphite (ADKSTAB PEP-8 of ADEKA CORPORATION)
and 0.05 parts by weight of trimethyl phosphate (TMP of Daihachi
Chemical Industry Co., Ltd.) were fed to a 30-mm-.phi.) vented
twin-screw extruder (TEX30XSST of Japan Steel Works, Ltd.),
melt-extruded at a cylinder temperature of 230.degree. C., a screw
rotation speed of 150 rpm, a discharge rate of 20 kg/h and a vent
pressure reduction degree of 3 kPa, and pelletized. The obtained
pellets were dried by a hot-air circulation-type dryer at
100.degree. C. for 5 hours. After dried, the pellets were
injection-molded by an injection molding machine (IS-150EN of
Toshiba Machine Co., Ltd.) at a cylinder temperature of 230.degree.
C., a mold temperature of 80.degree. C. and a molding cycle of 180
seconds to obtain a molded piece.
Example 18
[0368] 100 parts by weight of the polylactic acid 3 produced in
Production Example 7, 100 parts by weight of ABS resin (KRALASTIC
GA-704 of NIPPON A&L INC.), 0.1 parts by weight of distearyl
pentaerythritol diphosphite (ADKSTAB PEP-8 of ADEKA CORPORATION)
and 0.05 parts by weight of trimethyl phosphate (TMP of Daihachi
Chemical Industry Co., Ltd.) were fed to a 30-mm-.phi. vented
twin-screw extruder (TEX30XSST of Japan Steel Works, Ltd.),
melt-extruded at a cylinder temperature of 230.degree. C., a screw
rotation speed of 150 rpm, a discharge rate of 20 kg/h and a vent
pressure reduction degree of 3 kPa, and pelletized. The obtained
pellets were dried by a hot-air circulation-type dryer at
100.degree. C. for 5 hours. After dried, the pellets were
injection-molded by an injection molding machine (IS-150EN of
Toshiba Machine Co., Ltd.) at a cylinder temperature of 230.degree.
C., a mold temperature of 80.degree. C. and a molding cycle of 180
seconds to obtain a molded piece.
Example 19
[0369] 100 parts by weight of the polylactic acid 3 produced in
Production Example 7, 100 parts by weight of ABS resin (KRALASTIC
S3710 of NIPPON A&L INC.), 0.1 parts by weight of distearyl
pentaerythritol diphosphite (ADKSTAB PEP-8 of ADEKA CORPORATION)
and 0.05 parts by weight of trimethyl phosphate (TMP of Daihachi
Chemical Industry Co., Ltd.) were fed to a 30-mm-.phi. vented
twin-screw extruder (TEX30XSST of Japan Steel Works, Ltd.),
melt-extruded at a cylinder temperature of 230.degree. C., a screw
rotation speed of 150 rpm, a discharge rate of 20 kg/h and a vent
pressure reduction degree of 3 kPa, and pelletized. The obtained
pellets were dried by a hot-air circulation-type dryer at
100.degree. C. for 5 hours. After dried, the pellets were
injection-molded by an injection molding machine (IS-150EN of
Toshiba Machine Co., Ltd.) at a cylinder temperature of 230.degree.
C., a mold temperature of 80.degree. C. and a molding cycle of 180
seconds to obtain a molded piece.
Example 20
[0370] 100 parts by weight of the polylactic acid 3 produced in
Production Example 7, 100 parts by weight of polyethylene resin
(HI-ZEX 7000F of Prime Polymer Co., Ltd.), 0.1 parts by weight of
distearyl pentaerythritol diphosphite (ADKSTAB PEP-8 of ADEKA
CORPORATION) and 0.1 parts by weight of hindered phenol antioxidant
(IRGANOX 1076 of Ciba Specialty Chemicals) were fed to a
30-mm-.phi. vented twin-screw extruder (TEX30XSST of Japan Steel
Works, Ltd.), melt-extruded at a cylinder temperature of
230.degree. C., a screw rotation speed of 150 rpm, a discharge rate
of 20 kg/h and a vent pressure reduction degree of 3 kPa, and
pelletized. The obtained pellets were dried by a hot-air
circulation-type dryer at 100.degree. C. for 5 hours. After dried,
the pellets were injection-molded by an injection molding machine
(IS-150EN of Toshiba Machine Co., Ltd.) at a cylinder temperature
of 230.degree. C., a mold temperature of 80.degree. C. and a
molding cycle of 180 seconds to obtain a molded piece.
[0371] All components were mixed uniformly by use of a tumbler to
prepare a premixture, and the mixture was fed from the first feed
port of the extruder.
Examples 21 to 24 and Comparative Example 2
Optical Disk Substrates
(Pellets)
[0372] Aromatic polycarbonate resins (component A), polylactic
acids (component B), crystal nucleating agents (component C) and
phosphorus stabilizers (component P) were mixed uniformly by use of
a tumbler according to compositions shown in Table 2 to prepare
premixtures, and the mixtures were fed to a 30-mm-.phi. vented
twin-screw extruder [TEX30XSST of Japan Steel Works, Ltd.] from its
first feed port, melt-extruded at a cylinder temperature of
260.degree. C., a screw rotation speed of 150 rpm, a discharge rate
of 20 kg/h and a vent pressure reduction degree of 3 kPa, and
pelletized.
[0373] As for screw configuration, a first kneading zone
(comprising two forward kneading disks, one forward rotor, one
backward rotor and one backward kneading disk) was provided before
a side feeder position, and a second kneading zone (comprising one
forward rotor and one backward rotor) was provided after the side
feeder position.
(Test Pieces)
[0374] The obtained pellets were dried by a hot-air
circulation-type dryer at 100.degree. C. for 5 hours. After dried,
the pellets were molded into test pieces for evaluating flexural
strength, flexural modulus, deflection temperature under load and
hydrolysis resistance, by an injection molding machine (IS-150EN of
Toshiba Machine Co., Ltd.) at a cylinder temperature of 240.degree.
C., a mold temperature of 80.degree. C. and a molding cycle of 80
seconds. The following properties of the test pieces were measured
in the same manners as described above.
(1) Proportion of Melt Peaks at 195.degree. C. or Higher
(2) Flexural Strength
(3) Flexural Modulus
[0375] (4) Deflection Temperature under Load
(5) Hydrolysis Resistance
[0376] The results of measurements are shown in Table
(Optical Disk Substrates)
[0377] Then, optical disk substrates having a diameter of 120 mm
and a thickness of 1.2 mm were molded from the dried pellets by use
of an injection molding machine (M35B-D-DM of MEIKI CO., LTD.) and
a CD stamper (pit depth: 100 nm, pit pitch: 1.6 .mu.m) at a
cylinder temperature of 250.degree. C., a mold temperature of
80.degree. C. and a molding cycle of 60 seconds. Various properties
of the optical disk substrates were measured. The measurement
results thereof are shown in Table 2.
(1) Chemical Resistance:
[0378] After the optical disk substrate was immersed in methanol at
room temperature for one week, its surface condition was observed
and rated based on the following criteria.
.circleincircle.: No change is observed. .largecircle.: Slight
surface roughness of acceptable degree as a product is observed. x:
Surface roughness of unacceptable degree as a product is
observed.
(2) Transfer Rate:
[0379] The depths of grooves transferred onto the optical disk
substrate were measured at 5 points which were at 40 mm from the
center toward the periphery, by use of an electron microscope
(SPI3700 of Seiko Instruments Inc.). Transferability was expressed
as a transfer rate represented by the following formula.
Transfer Rate(%)=100.times. Depth of Groove on Disk/Depth of Groove
of Stamper
The closer this value is to 100%, the better transferability the
optical disk substrate has. PS (3) Surface Condition:
[0380] The surface condition of the stamper nontransferred surface
of the optical disk substrate was observed at a position which was
at 40 mm from the center of the stamper toward the periphery, by
means of a confocal reflecting microscope (MX50 of Olympus
Corporation) and rated based on the following criteria.
.largecircle.: Smoothness abnormalities such as exposed foreign
matters and fine sinks are not observed at all. .DELTA.: Some
smoothness abnormalities are observed. x: Smoothness abnormalities
are clearly observed.
(Optical Disks)
[0381] Then, optical disks were prepared in the following manner.
On the optical disk substrate, an Al metal layer having a thickness
of 70 nm was formed by sputtering to form a recording layer of a
compact disk. After an ultraviolet curable resin was coated on this
recording layer to a thickness of 10 .mu.m by spin coating, the
resin was cured by ultraviolet irradiation to form a protective
layer. The heat resistance of the optical disk was evaluated in the
following manner.
(1) Heat Resistance:
[0382] After the optical disk was heat-treated under the conditions
provided in JIS S 8605 (55.degree. C., relative humidity of 70%, 96
hours), it was played on a commercial CD player. The disk was rated
as ".largecircle." if it could be played without problems and rated
as "x" if not.
TABLE-US-00003 TABLE 2 C. Ex. 2 Ex. 21 Ex. 22 Ex. 23 Ex. 24
Component A A-1 100 100 100 100 100 Component B B-3 20 -- -- -- --
B-6 -- -- -- -- -- B-2 -- -- -- -- -- B-5 -- -- -- -- -- Polylactic
Acid 1 -- 20 20 -- -- Polylactic Acid 2 -- -- -- 20 -- Polylactic
Acid 3 -- -- -- -- 20 Component C C-1 -- -- 0.5 -- -- Other P-1 0.1
0.1 0.1 0.1 0.1 Test Piece R.sub.195 or higher (%) 0 35 47 96 97
Flexural Strength (MPa) 97 96 96 97 97 Flexural Modulus (MPa) 2300
2300 2300 2300 2300 Deflection Temperature under Load (.degree. C.)
116 118 118 119 117 Hydrolysis Resistance 18 35 38 64 80 (Molecular
Weight Retention (%)) Optical Disk Chemical Resistance X
.largecircle. .largecircle. .circleincircle. .circleincircle.
Substrate Transfer Rate (%) 88 92 90 90 89 Surface Condition
.largecircle. .largecircle. .largecircle. .largecircle.
.largecircle. Heat Resistance of Optical Disk .largecircle.
.largecircle. .largecircle. .largecircle. .largecircle. (JIS S
8605) C. Ex.: Comparative Example, Ex.: Example
[0383] As is clear from Table 2, the resin compositions of the
present invention are excellent in heat resistance and hydrolysis
resistance. According to the present invention, an optical disk
substrate and an optical disk are obtained that are excellent in
chemical resistance, heat resistance and transferability and have a
good surface condition.
Examples 25 to 28 and Comparative Examples 3 to 6
Pellets
[0384] Polylactic acids (component B), crystal nucleating agents
(component C) and inorganic fillers (component D) were fed to a
30-mm-.phi. vented twin-screw extruder [TEX30XSST of Japan Steel
Works, Ltd.] according to compositions shown in Table 3,
melt-extruded at a cylinder temperature of 260.degree. C., a screw
rotation speed of 150 rpm, a discharge rate of 20 kg/h and a vent
pressure reduction degree of 3 kPa, and pelletized.
[0385] As for screw configuration, a first kneading zone
(comprising two forward kneading disks, one forward rotor, one
backward rotor and one backward kneading disk) was provided before
a side feeder position, and a second kneading zone (comprising one
forward rotor and one backward rotor) was provided after the side
feeder position.
[0386] Productions of the pellets in the above Examples and
Comparative Example were carried out in the following manners
(descriptions of the components are given by use of the above
symbols).
(i) Examples 25 to 27 and Comparative Examples 3 to 6
[0387] All components were mixed uniformly by use of a tumbler to
prepare a premixture, and the mixture was fed from a first feed
port of the extruder.
(ii) Example 28
[0388] The inorganic filler D-1 was fed from a second feed port by
use of a side feeder, and the remaining components were premixed by
use of a tumbler and fed from the first feed port.
(Test Pieces)
[0389] The obtained pellets were dried by a hot-air
circulation-type dryer at 100.degree. C. for 5 hours. The dried
pellets were molded into test pieces for evaluating flexural
strength, flexural modulus, deflection temperature under load and
hydrolysis resistance, by an injection molding machine (IS-150EN of
Toshiba Machine Co., Ltd.) at mold temperatures shown in Table 3, a
cylinder temperature of 240.degree. C. and a molding cycle of 180
seconds. By use of these test pieces, the following properties
excluding hydrolysis resistance and chemical resistance 1 were
measured in the same manners as described above. The measurement
results and injection moldabilities thereof are shown in Table 3.
The R.sub.195 or higher of notebook-size personal computer housing
and office automation equipment exterior part were evaluated by
cutting test pieces out of molded articles.
(1) Proportion (R.sub.195 or higher) of Melt Peaks at 195.degree.
C. or higher
(2) Flexural Strength
(3) Flexural Modulus
[0390] (4) Deflection Temperature under Load
(5) Hydrolysis Resistance:
[0391] The molecular weight of test piece prepared in accordance
with ISO178 after it was treated in a pressure cooker tester at
120.degree. C. and a relative humidity of 100% for 8 hours was
evaluated by retention with respect to the value before the
treatment. To calculate the retention, a weight average molecular
weight (Mw) in terms of polystyrene determined from GPC was
used.
(6) Chemical Resistance:
(i) Test 1
[0392] After the same test piece as used for evaluation of the
above flexural strength was immersed in methanol at room
temperature for one month, its surface condition was observed and
rated based on the following criteria.
x: Surface roughness occurred.
.largecircle.: Good.
[0393] (ii) Test 2 (automobile part), (iii) test 3 (connector),
(iv) test 4 (notebook-size personal computer housing) and (v) test
5 (OA equipment exterior part) were measured and evaluated in the
same manners as described above.
TABLE-US-00004 TABLE 3 C. Ex. 3 C. Ex. 4 C. Ex. 5 C. Ex. 6 Ex. 25
Ex. 26 Ex. 27 Ex. 28 Component B B-3 100 100 -- -- -- -- -- -- B-6
-- -- -- -- -- -- -- -- B-2 -- -- -- -- -- -- -- -- B-5 -- -- -- --
-- -- -- -- Polylactic Acid 1 -- -- 100 -- -- -- -- -- Polylactic
Acid 4 -- -- -- 100 -- -- -- -- Polylactic Acid 5 -- -- -- -- 100
-- -- -- Polylactic Acid 2 -- -- -- -- 100 -- 100 Components B + E
Polylactic Acid 3 -- -- -- -- 100 -- Component C C-1 1 1 1 1 1 1 1
1 Component D D-1 -- -- -- -- -- -- -- 40 R.sub.195 or higher of
Pellets (%) 0 0 40 55 84 97 96 97 Mold Temperature (.degree. C.)
110 30 110 110 110 110 110 110 Injection Moldability I.M. M I.M.
I.M. M M M M Test Piece R.sub.195 or higher (%) -- 0 -- -- 85 97 96
98 Flexural Strength (MPa) -- 96 -- -- 97 98 97 142 Flexural
Modulus (MPa) -- 3500 -- -- 3800 3800 3800 9000 Deflection
Temperature under Load (.degree. C.) -- 50 -- -- 66 65 66 180
Hydrolysis Resistance Before Test -- 112000 -- -- 107000 106000
103000 106000 (Weight Average Molecular After Test -- 9000 -- --
26000 33000 44000 32000 Weight) Retention (%) -- 8 -- -- 24 31 43
30 Chemical Test 1 -- X -- -- .largecircle. .largecircle.
.largecircle. .largecircle. Resistance Test 2 (Automobile Part) --
X -- -- .largecircle. .largecircle. .largecircle. .largecircle.
Test 3 (Connector) -- X -- -- .largecircle. .largecircle.
.largecircle. .largecircle. Test 4 (Notebook-size Computer Housing)
-- X -- -- .largecircle. .largecircle. .largecircle. .largecircle.
Test 5 (OA Equipment Exterior Part) -- X -- -- .largecircle.
.largecircle. .largecircle. .largecircle. C. Ex.: Comparative
Example, Ex.: Example I.M.: Immoldable, M: Moldable
[0394] It can be clearly seen from the results shown in Table 3
that the resin compositions of the present invention have excellent
injection moldability and the obtained molded articles have
significantly improved hydrolysis resistance. Further, it can be
seen that improvements in mechanical properties due to inclusion of
the inorganic filler and a further improvement in hydrolysis
resistance due to inclusion of the terminal blocking agent have
been achieved.
Examples 29 to 31 and Comparative Examples 7 to 10
Optical Disk Substrates
[0395] Pellets were prepared in the following manner, and flexural
test pieces complying with ISO178 and disk substrates were produced
and evaluated.
(Pellets)
[0396] Polylactic acids (component B), crystal nucleating agents
(component C) and phosphorus stabilizers (component P) were mixed
uniformly by use of a tumbler according to compositions shown in
Table 4 to prepare premixtures, and the mixtures were fed to a
30-mm-.phi. vented twin-screw extruder [TEX30XSST of Japan Steel
Works, Ltd.] from its first feed port, melt-extruded at a cylinder
temperature of 260.degree. C., a screw rotation speed of 150 rpm, a
discharge rate of 20 kg/h and a vent pressure reduction degree of 3
kPa, and pelletized.
[0397] As for screw configuration, a first kneading zone
(comprising two forward kneading disks, one forward rotor, one
backward rotor and one backward kneading disk) was provided before
a side feeder position, and a second kneading zone (comprising one
forward rotor and one backward rotor) was provided after the side
feeder position.
(Test Pieces)
[0398] The obtained pellets were dried by a hot-air
circulation-type dryer at 100.degree. C. for 5 hours. Thereafter,
the pellets were molded into test pieces for evaluating flexural
strength, flexural modulus and deflection temperature under load,
by an injection molding machine (IS-150EN of Toshiba Machine Co.,
Ltd.) at mold temperatures shown in Table 4, a cylinder temperature
of 240.degree. C. and a molding cycle of 180 seconds. The test
pieces were evaluated for the following items in the same manners
as described above.
(1) Proportion of Melt Peaks at 195.degree. C. or Higher
(2) Flexural Strength
(3) Flexural Modulus
[0399] (4) Deflection Temperature under Load
(5) Hydrolysis Resistance
(Optical Disk Substrates)
[0400] Then, optical disk substrates having a diameter of 120 mm
and a thickness of 1.2 mm were molded from the dried pellets by use
of an injection molding machine (M35B-D-DM of MEIKI CO., LTD.) and
a CD stamper (pit depth: 100 nm, pit pitch: 1.6 .mu.m) at mold
temperatures shown in Table 4, a cylinder temperature of
250.degree. C. and a molding cycle of 60 seconds. The following
properties of the obtained optical disk substrates were measured in
the same manners as described above. The measurement results and
injection moldabilities thereof are shown in Table 4.
(1) Transfer Rate
(2) Surface Condition
(Optical Disks)
[0401] Then, optical disks were prepared in the following manner.
On the optical disk substrate, an Al metal layer having a thickness
of 70 nm was formed by sputtering to form a recording layer of a
compact disk. After an ultraviolet curable resin was coated on this
recording layer to a thickness of 10 .mu.m by spin coating, the
resin was cured by ultraviolet irradiation to form a protective
layer. The heat resistance of the optical disk was evaluated in the
same manner as described above.
TABLE-US-00005 TABLE 4 C. Ex. 7 C. Ex. 8 C. Ex. 9 C. Ex. 10 Ex. 29
Ex. 30 Ex. 31 Component B B-3 100 100 -- -- -- -- -- B-6 -- -- --
-- -- -- -- B-2 -- -- -- -- -- -- -- B-5 -- -- -- -- -- -- --
Polylactic Acid 1 -- -- 100 -- -- -- -- Polylactic Acid 4 -- -- --
100 -- -- -- Polylactic Acid 5 -- -- -- -- 100 -- -- Polylactic
Acid 2 -- -- -- -- -- 100 -- Polylactic Acid 3 -- -- -- -- -- --
100 Component C C-1 1 1 1 1 1 1 1 Other P-1 0.1 0.1 0.1 0.1 0.1 0.1
0.1 R.sub.195 or higher of Pellets (%) 0 0 40 55 84 97 96 Test
Piece Mold Temperature of Injection Molding (.degree. C.) 110 30
110 110 110 110 110 Injection Moldability I.M. M I.M. I.M. M M M
R.sub.195 or higher (%) -- 0 -- -- 85 97 96 Flexural Strength (MPa)
-- 96 -- -- 97 98 97 Flexural Modulus (MPa) -- 3500 -- -- 3800 3800
3800 Deflection Temperature under Load (.degree. C.) -- 50 -- -- 66
65 66 Hydrolysis Resistance -- 8 -- -- 24 31 43 (Molecular Weight
Retention (%)) Optical Disk Mold Temperature of Injection Molding
(.degree. C.) 80 80 80 80 80 80 80 Substrate Injection Moldability
I.M. M I.M. I.M. M M M Substrate Transfer Rate (%) -- 30 -- -- 95
96 94 Surface Condition of Substrate -- X -- -- .largecircle.
.largecircle. .largecircle. Heat Resistance of Optical Disk (JIS S
8605) -- X -- -- .largecircle. .largecircle. .largecircle. C. Ex.:
Comparative Example, Ex.: Example I.M.: Immoldable, M: Moldable
[0402] As is clear from Table 4, the resin compositions of the
present invention have excellent injection moldability. According
to the present invention, optical disk substrates that are
excellent in transfer rate, surface condition, heat resistance and
hydrolysis resistance are obtained.
Examples 32 to 34 and Comparative Example 11
Extruded Articles
[0403] Polylactic acid pellets of compositions shown in Table 5
were prepared and dried at 90.degree. C. for 5 hours. Then, the
pellets were fed to an extruder hopper, molten at a melt
temperature of 250.degree. C., extruded onto a rotating cooling
drum having a surface temperature of 25.degree. C. through a 1-mm
slit die, and quenched to obtain sheets having a thickness of 0.3
mm. The following properties of the obtained sheets were evaluated
in the following manners. A proportion of melt peaks at 195.degree.
C. or higher was evaluated in the same manner as described above.
The results are shown in Table 5.
(1) Proportion of Melt Peaks at 195.degree. C. or Higher
[0404] (2) Tensile Strength, Modulus of tensile elasticity:
[0405] These were measured in accordance with JIS-C2318.
(3) Hydrolysis Resistance:
[0406] The weight average molecular weight (Mw) of the polylactic
acid after the sheet was treated in a thermo-hygrostat at
65.degree. C. and a relative humidity of 95% for 100 hours was
evaluated by retention with respect to the value before the
treatment.
TABLE-US-00006 TABLE 5 C. Ex. 11 Ex. 32 Ex. 33 Ex. 34 Component B
B-3 100 -- -- -- B-6 -- -- -- -- B-2 -- -- -- -- B-5 -- -- -- --
Polylactic Acid 1 -- -- -- -- Polylactic Acid 4 -- -- -- --
Polylactic Acid 5 -- 100 -- -- Polylactic Acid 2 -- -- 100 --
Components B + C Polylactic Acid 3 -- -- -- 100 Pellets R.sub.195
or higher (%) 0 84 97 96 Extruded Article R.sub.195 or higher of
Extruded Article (%) 0 82 97 97 Tensile Strength (MPa) 70 72 73 72
Modulus of tensile elasticity (MPa) 2,000 2,100 2,100 2,100
Hydrolysis Resistance 55 86 90 98 (Molecular Weight Retention (%))
C. Ex.: Comparative Example, Ex.: Example
[0407] As is clear from Table 5, the extruded articles of the
present invention have excellent mechanical properties and
hydrolysis resistance.
Examples 35 to 37 and Comparative Example 12
Heat Molded Articles
[0408] Polylactic acid pellets of compositions shown in Table 6
were prepared and dried at 90.degree. C. for 5 hours. Then, the
pellets were fed to an extruder hopper, molten at a melt
temperature of 250.degree. C., extruded onto a rotating cooling
drum having a surface temperature of 25.degree. C. through a 1-mm
slit die, and quenched to obtain sheets having a thickness of 0.5
mm. After preheated, these sheets were subjected to vacuum
air-pressure molding by use of FC-1APA-W type vacuum air-pressure
molding machine of Asano Laboratories Co., Ltd. with a tray-shaped
mold having an opening of 56 mm.times.121 mm, a bottom of 38
mm.times.102 mm and a depth of 20 mm attached thereto.
Moldabilities and the properties of the obtained heat molded
articles were evaluated in the following manners. A proportion of
melt peaks at 195.degree. C. or higher was evaluated in the same
manner as described above. The results are shown in Table 6.
(1) Proportion of Melt Peaks at 195.degree. C. or Higher
(2) Moldability:
[0409] This was evaluated by observing the shape of the heat molded
article.
(3) Hydrolysis Resistance:
[0410] The weight average molecular weight (Mw) of the polylactic
acid after the heat molded article was treated in a
thermo-hygrostat at 65.degree. C. and a relative humidity of 95%
for 100 hours was evaluated by retention with respect to the value
before the treatment.
TABLE-US-00007 TABLE 6 C. Ex. 12 Ex. 35 Ex. 36 Ex. 37 Component B-3
100 -- -- -- B B-6 -- -- -- -- B-2 -- -- -- -- B-5 -- -- -- --
Polylactic Acid 1 -- -- -- -- Polylactic Acid 4 -- -- -- --
Polylactic Acid 5 -- 100 -- -- Polylactic Acid 2 -- -- 100 --
Components Polylactic Acid 3 -- -- -- 100 B + E Pellets R.sub.195
or higher (%) 0 84 97 96 Heat Molded Moldability Good Good Good
Good Article R.sub.195 or higher of 0 82 98 97 Heat Molded Article
(%) Hydrolysis 54 86 91 98 Resistance (Molecular Weight Retention
(%)) C. Ex.: Comparative Example, Ex.: Example
[0411] As is clear from Table 6, the resin compositions of the
present invention have excellent heat moldability. The heat molded
articles of the present invention have excellent hydrolysis
resistance.
Examples 38 to 40 and Comparative Example 13
Blow Molded Articles
[0412] Polylactic acid pellets of compositions shown in Table 7
were prepared and dried at 90.degree. C. for 5 hours. Then, the
pellets were injection-molded into preforms by an injection molding
machine 100DM of MEIKI CO., LTD., and the obtained preforms were
blow-molded into hollow molded articles having an inner volume of
1.55 liters and a barrel wall thickness of 300 .mu.m. As for
conditions for the injection molding, the cylinder temperature was
set at 250.degree. C., and the molding cycle was 60 seconds. The
blow molding was carried out by use of an LB01 blow molding machine
of CORPOPLAST CO., LTD. The properties of the obtained hollow
molded articles were measured in the following manners. A
proportion of melt peaks at 195.degree. C. or higher was evaluated
in the same manner as described above. The results are shown in
Table 7.
(1) Proportion of Melt Peaks at 195.degree. C. or Higher
(2) Drop Breakage Rate:
[0413] After carbonated water was filled in the hollow molded
article, it was dropped from a height of 0.5 m onto concrete having
a slope angle of 30.degree. to determine a breakage rate, thereby
evaluating impact resistance. PS (3) Hydrolysis Resistance:
[0414] The weight average molecular weight (Mw) of the polylactic
acid after the hollow molded article was treated in a
thermo-hygrostat at 65.degree. C. and a relative humidity of 95%
for 100 hours was evaluated by retention with respect to the value
before the treatment.
TABLE-US-00008 TABLE 7 C. Ex. 13 Ex. 38 Ex. 39 Ex. 40 Component B
B-3 100 -- -- -- B-6 -- -- -- -- B-2 -- -- -- -- B-5 -- -- -- --
Polylactic Acid 1 -- -- -- -- Polylactic Acid 4 -- -- -- --
Polylactic Acid 5 -- 100 -- -- Polylactic Acid 2 -- -- 100 --
Components Polylactic Acid 3 -- -- -- 100 B + E Pellets R.sub.195
or higher (%) 0 84 97 96 Blow Molded R.sub.195 or higher (%) 0 81
97 98 Article Drop Breakage 5 0 0 0 Rate (%) Hydrolysis 56 84 90 98
Resistance (Molecular Weight Retention (%)) C. Ex.: Comparative
Example, Ex.: Example
[0415] As is clear from Table 7, the blow molded articles of the
present invention have excellent mechanical properties and
hydrolysis resistance. Further, it can be seen that the terminal
blocking agent (component E) improves hydrolysis resistance.
Examples 41 to 43 and Comparative Example 14
Foam Molded Articles
[0416] Polylactic acid pellets of compositions shown in Table 8
were prepared and dried at 90.degree. C. for 5 hours. Then, the
pellets were subjected to extrusion foaming using a single-screw
extruder (diameter: 40 mm, L/D: 30) with 5-mm-.phi. nozzle mold
attached thereto. In the extrusion foaming, liquefied butane gas as
a foaming agent was injected at the middle of the extrusion
cylinder in a proportion of 2.0 parts based on 100 parts of molten
material, and a good rod-shaped foam molded article comprising fine
bubbles was obtained at a rate of 5 kg/hr under the following
conditions, i.e. at a temperature of the feed section of the
extruder of 150 to 180.degree. C., a temperature of the compression
section of the extruder of 180 to 220.degree. C., a temperature of
the melting section of the extruder of 180 to 220.degree. C., a
temperature of the head of the extruder of 160 to 200.degree. C., a
temperature of the mold of the extruder of 160 to 200.degree. C.,
and a screw rotation speed of 32 rpm.
[0417] The foam molded article was sampled at 20 minutes after the
start of production of the foam molded article, and the physical
properties of the foam molded article were measured in the
following manners. A proportion of melt peaks at 195.degree. C. or
higher was evaluated in the same manner as described above.
(1) Proportion of Melt Peaks at 195.degree. C. or Higher
(2) Apparent Density:
[0418] This was measured in accordance with JIS-K7222. PS (3)
Condition of Bubbles:
[0419] The condition of bubbles in the foam molded article was
evaluated by an optical microscope
(magnification: 60-fold).
(4) Hydrolysis Resistance:
[0420] The weight average molecular weight (Mw) of the polylactic
acid after the foam molded article was treated in a
thermo-hygrostat at 65.degree. C. and a relative humidity of 95%
for 100 hours was evaluated by retention with respect to the value
before the treatment. The measurement results thereof are shown in
Table 8.
TABLE-US-00009 TABLE 8 C. Ex. 14 Ex. 41 Ex. 42 Ex. 43 Component B
B-3 100 -- -- -- B-6 -- -- -- -- B-2 -- -- -- -- B-5 -- -- -- --
Polylactic Acid 1 -- -- -- -- Polylactic Acid 4 -- -- -- --
Polylactic Acid 5 -- 100 -- -- Polylactic Acid 2 -- -- 100 --
Components Polylactic Acid 3 -- -- -- 100 B + E Pellets R.sub.195
or higher (%) 0 84 97 96 Foam Molded R.sub.195 or higher (%) 0 83
97 98 Article Density (kg/m.sup.3) 600 520 510 520 Condition of
Small Fine Fine Fine Bubbles Hydrolysis 54 85 92 98 Resistance
(Molecular Weight Retention (%)) C. Ex.: Comparative Example, Ex.:
Example
[0421] As shown in Table 8, the foam molded articles of the present
invention have excellent hydrolysis resistance. Further, the foam
molded article has further improved hydrolysis resistance by
containing the terminal blocking agent (component E).
EFFECT OF THE INVENTION
First Aspect
[0422] Since the present invention uses a polylactic acid obtained
from biomass resources, it can provide a resin composition and a
molded article that cause small burdens on the environment. The
resin composition of the present invention that comprises the
thermoplastic resin (component A) and the polylactic acid
(component B) has a large R.sub.195 or higher value, high
crystallinity and a high melting point. The resin composition of
the present invention has excellent heat resistance, hydrolysis
resistance and chemical resistance. According to the method of the
present invention for producing a resin composition, a resin
composition having excellent properties as described above can be
produced.
[0423] The molded articles of the present invention have excellent
mechanical properties such as flexural strength and flexural
modulus. They also have high deflection temperature under load and
excellent heat resistance. They also have excellent hydrolysis
resistance and chemical resistance. According to the method of the
present invention for producing a molded article, a molded article
having excellent properties as described above can be produced.
Second Aspect
[0424] Since the present invention uses a polylactic acid obtained
from biomass resources, it can provide a resin composition and a
molded article that cause small burdens on the environment. The
resin composition of the present invention that comprises the
polylactic acid (component B) has a large R.sub.195 or higher
value, high crystallinity and a high melting point. The resin
composition of the present invention has excellent heat resistance,
hydrolysis resistance and chemical resistance. According to the
method of the present invention for producing a resin composition,
a resin composition having excellent properties as described above
can be produced.
[0425] The molded articles of the present invention have excellent
mechanical properties such as flexural strength and flexural
modulus. They also have high deflection temperature under load and
excellent heat resistance. They also have excellent hydrolysis
resistance and chemical resistance. According to the method of the
present invention for producing a molded article, a molded article
having excellent properties as described above can be produced.
INDUSTRIAL APPLICABILITY
[0426] Since the molded articles of the present invention have
excellent heat resistance, mechanical properties, hydrolysis
resistance and chemical resistance, they are useful for various
applications such as various electronic/electric equipments, OA
equipments, vehicle parts, machine parts, other agricultural
materials, fishing materials, shipping containers, packaging
containers, play equipments and miscellaneous goods.
* * * * *