U.S. patent application number 15/661131 was filed with the patent office on 2018-09-27 for resin composition for resin molding, and resin molding.
This patent application is currently assigned to FUJI XEROX CO., LTD.. The applicant listed for this patent is FUJI XEROX CO., LTD.. Invention is credited to Tsuyoshi MIYAMOTO, Hiroyuki MORIYA, Masayuki OKOSHI.
Application Number | 20180273737 15/661131 |
Document ID | / |
Family ID | 59655977 |
Filed Date | 2018-09-27 |
United States Patent
Application |
20180273737 |
Kind Code |
A1 |
MIYAMOTO; Tsuyoshi ; et
al. |
September 27, 2018 |
RESIN COMPOSITION FOR RESIN MOLDING, AND RESIN MOLDING
Abstract
A resin composition for resin moldings includes: a first resin
composition containing a first polyolefin, a polyamide, first
carbon fibers having an average fiber length of 0.1 mm to 1 mm and
a carboxylic anhydride-modified polyolefin as a compatibilizer; and
a second resin composition containing a second polyolefin and
second carbon fibers having an average fiber length of 6 mm to 20
mm, wherein of the whole quantity of the resin composition for
resin moldings, taking the total contents of the first polyolefin
and the second polyolefin as 100 parts by mass, a content of the
polyamide accounts for 1 part by mass to 50 parts by mass, the
total contents for the first carbon fiber and the second carbon
fiber account for 1 part by mass to 50 parts by mass and a content
of the compatibilizer accounts for 1 part by mass to 10 parts by
mass.
Inventors: |
MIYAMOTO; Tsuyoshi;
(Minamiashigara-shi, JP) ; MORIYA; Hiroyuki;
(Minamiashigara-shi, JP) ; OKOSHI; Masayuki;
(Minamiashigara-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
FUJI XEROX CO., LTD. |
Tokyo |
|
JP |
|
|
Assignee: |
FUJI XEROX CO., LTD.
Tokyo
JP
|
Family ID: |
59655977 |
Appl. No.: |
15/661131 |
Filed: |
July 27, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C08L 2205/08 20130101;
C08J 2323/08 20130101; C08L 23/12 20130101; C08J 2323/12 20130101;
C08L 2205/16 20130101; C08L 2205/035 20130101; C08J 2323/06
20130101; C08J 5/042 20130101; C08L 23/0853 20130101; C08J 2451/06
20130101; C08J 2477/00 20130101; C08L 23/06 20130101; C08L 23/12
20130101; C08L 77/00 20130101; C08L 51/06 20130101; C08K 7/06
20130101; C08L 23/06 20130101; C08L 77/00 20130101; C08L 51/06
20130101; C08K 7/06 20130101; C08L 23/0853 20130101; C08L 77/00
20130101; C08L 51/06 20130101; C08K 7/06 20130101 |
International
Class: |
C08L 23/12 20060101
C08L023/12; C08L 23/06 20060101 C08L023/06; C08L 23/08 20060101
C08L023/08 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 24, 2017 |
JP |
2017-058682 |
Claims
1. A resin composition for resin moldings, comprising: a first
resin composition containing a first polyolefin, a polyamide, first
carbon fibers having an average fiber length of 0.1 mm to 1 mm and
a carboxylic anhydride-modified polyolefin as a compatibilizer; and
a second resin composition containing a second polyolefin and
second carbon fibers having an average fiber length of 6 mm to 20
mm, wherein of the whole quantity of the resin composition for
resin moldings, taking the total contents of the first polyolefin
and the second polyolefin as 100 parts by mass, a content of the
polyamide accounts for 1 part by mass to 50 parts by mass, the
total contents for the first carbon fiber and the second carbon
fiber account for 1 part by mass to 50 parts by mass and a content
of the compatibilizer accounts for 1 part by mass to 10 parts by
mass.
2. The resin composition for resin moldings according to claim 1,
wherein a mass ratio CF1/CF2 is from at least 10/90 to at most
90/10, wherein CF1 represents a content of the first carbon fiber
with respect to the whole quantity of the resin composition for
resin moldings and CF2 represents a content of the second carbon
fiber with respect to the whole quantity of the resin composition
for resin moldings.
3. The resin composition for resin moldings according to claim 1,
wherein each of the first polyolefin and the second polyolefin is
at least one polymer selected from the group consisting of
polypropylene, polyethylene and ethylene-vinyl acetate copolymer
resin.
4. The resin composition for resin moldings according to claim 3,
wherein each of the first polyolefin and the second polyolefin is a
polypropylene.
5. The resin composition for resin moldings according to claim 1,
wherein the compatibilizer is at least one selected from the group
of modified polyolefins including a modified polypropylene, a
modified polyethylene and a modified ethylene-vinyl acetate
copolymer, the modified polyolefins each having a modified moiety
containing a carboxylic anhydride residue.
6. The resin composition for resin moldings according to claim 5,
wherein the carboxylic anhydride residue is a maleic anhydride
residue.
7. The resin composition for resin moldings according to claim 6,
wherein the compatibilizer is a maleic anhydride-modified
polypropylene.
8. The resin composition for resin moldings according to claim 1,
wherein part of the polyamide forms a covering layer around the
periphery of each of the first carbon fibers in the first resin
composition.
9. The resin composition for resin moldings according to claim 8,
wherein the compatibilizer forms an intervening layer between the
covering layer and the first polyolefin in the first resin
composition.
10. The resin composition for resin moldings according to claim 1,
wherein each of the first resin composition and the second resin
composition is a non-crosslinked resin composition.
11. A resin molding containing: a polyolefin; a polyamide in a
content of 1 part by mass to 50 parts by mass per 100 parts of the
polyolefin; carbon fibers in a content of 1 part by mass to 50
parts by mass per 100 parts by mass of the polyolefin, the carbon
fibers having an average fiber length of 0.2 mm to 1 mm and
including a carbon fiber having a fiber length in a range of 1 mm
to 20 mm in a proportion of 1% to 20% by number to all the carbon
fibers; and a carboxylic anhydride-modified polyolefin as a
compatibilizer in a content of 1 part by mass to 10 parts by mass
per 100 parts by mass of the polyolefin.
12. The resin molding according to claim 11, wherein the polyolefin
is at least one selected from the group consisting of
polypropylene, polyethylene and ethylene-vinyl acetate
copolymer.
13. The resin molding according to claim 12, wherein the polyolefin
is a polypropylene.
14. The resin molding according to claim 11, wherein the
compatibilizer is at least one selected from the group of modified
polyolefins including a modified polypropylene, a modified
polyethylene and a modified ethylene-vinyl acetate copolymer, the
modified polyolefins each having a modified moiety containing a
carboxylic anhydride residue.
15. The resin molding according to claim 14, wherein the carboxylic
anhydride residue is a maleic anhydride residue.
16. The resin molding according to claim 15, wherein the
compatibilizer is a maleic anhydride-modified polypropylene.
17. The resin molding according to claim 11, wherein part of the
polyamide forms a covering layer around the periphery of each of
the carbon fibers.
18. The resin molding according to claim 17, wherein the
compatibilizer forms an intervening layer between the covering
layer and the polyolefin.
19. The resin molding according to claim 11, which is a
non-crosslinked resin molding.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is based on and claims a priority under 35
USC 119 from Japanese Patent Application No. 2017-058682 filed on
Mar. 24, 2017.
BACKGROUND
Technical Field
[0002] The present invention relates to a resin composition for a
resin molding and to a resin molding.
Related Art
[0003] Up to now various kinds of resin compositions have been
offered and put to a wide variety of uses.
[0004] Resin compositions containing polyolefin in particular have
been used e.g. for not only various kinds of components and
cabinets of household electric appliances and automobiles but also
parts such as cabinets of office instruments and
electrical-electronic instruments.
SUMMARY
[0005] According to an aspect of the invention, A resin composition
for resin moldings includes:
[0006] a first resin composition containing a first polyolefin, a
polyamide, first carbon fibers having an average fiber length of
0.1 mm to 1 mm and a carboxylic anhydride-modified polyolefin as a
compatibilizer; and
[0007] a second resin composition containing a second polyolefin
and second carbon fibers having an average fiber length of 6 mm to
20 mm,
[0008] wherein of the whole quantity of the resin composition for
resin moldings, taking the total contents of the first polyolefin
and the second polyolefin as 100 parts by mass, a polyamide content
accounts for 1 part by mass to 50 parts by mass, the total contents
of the first carbon fiber and the second carbon fiber accounts for
1 part by mass to 50 parts by mass and a content of the
compatibilizer accounts for 1 part by mass to 10 parts by mass.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] Exemplary embodiment(s) of the present invention will be
described in detail based on the following figures, wherein:
[0010] FIG. 1 is a schematic diagram for illustrating an example of
the main portions of resin moldings relating to embodiments of the
invention.
DETAILED DESCRIPTION
[0011] Examples of resin compositions and resin moldings according
to the invention are described below.
First Embodiment
(Resin Composition for Resin Molding)
[0012] A resin composition which relates to an embodiment of the
invention and is used for resin moldings (hereafter referred simply
to as "a resin composition" in some cases) includes a first resin
composition containing a first polyolefin, a polyamide, first
carbon fibers having an average fiber length of 0.1 mm to 1 mm and
a carboxylic anhydride-modified polyolefin as a compatibilizer and
a second resin composition containing a second polyolefin and
second carbon fibers having an average fiber length of 6 mm to 20
mm, and besides, of the whole quantity of the resin composition for
resin moldings, taking the total for the first polyolefin content
and the second polyolefin content as 100 parts by mass, a polyamide
content accounts for 1 part by mass to 50 parts by mass, the total
for a first carbon fiber content and a second carbon fiber content
accounts for 1 part by mass to 50 parts by mass and a
compatibilizer content accounts for 1 part by mass to 10 parts by
mass.
[0013] In other words, the resin composition relating to an
embodiment of the invention includes a first resin composition and
a second resin composition.
[0014] The first resin composition contains a first polyolefin, a
polyamide, first carbon fibers having an average fiber length of
0.1 mm to 1 mm (hereafter referred simply to as "first carbon
fibers" in some cases) and a carboxylic anhydride-modified
polyolefin as a compatibilizer.
[0015] The second resin composition contains a second polyolefin
and second carbon fibers having an average fiber length of 6 mm to
20 mm (hereafter referred simply to as "second carbon fibers" in
some cases).
[0016] Moreover, of the whole quantity of the resin composition,
taking the total for a first polyolefin content and a second
polyolefin content as 100 parts by mass, a polyamide content
accounts for 1 part by mass to 50 parts by mass, the total for a
first carbon fiber content and a second carbon fiber content
accounts for 1 part by mass to 50 parts by mass and a content of
carboxylic anhydride-modified polyolefin as a compatibilizer
(hereafter referred simply to as "compatibilizer content" in some
cases) accounts for 1 part by mass to 10 parts by mass.
[0017] In recent years, resin compositions each containing a
polyolefin resin as a base material (matrix) and reinforcing fibers
have been used for the purpose of obtaining resin moldings superior
in mechanical strength.
[0018] In such resin compositions, when affinity between the
reinforcing fibers and the polyolefin is low, spaces develop at the
interface between these ingredients, and there may be cases where
the spaces cause a reduction in adhesion at the interface.
[0019] When a resin composition contains as reinforcing fibers
carbon fibers in particular, though the resin composition is
required to ensure high mechanical strengths, notably a high
bending elasticity modulus, as compared with a resin composition
containing glass fibers or the like, polar groups contributing
adhesion between the reinforcing fibers and the polyolefin, such as
hydroxyl groups and carboxyl groups, present on the carbon fiber
surfaces are small in number as compared with those present on the
glass fiber surfaces, and therefore adhesion at carbon
fiber-polyolefin interfaces becomes low. As a result, the
mechanical strengths, notably a bending elasticity modulus, is hard
to increase, considering how much the carbon fibers are mixed. When
an impact is given repeatedly in particular, parting at the carbon
fiber-polyolefin interfaces is apt to progress, and hence there
develops a tendency to reduce mechanical strengths, notably a
bending elasticity modulus, to a large degree.
[0020] As a cause for this tendency, it is presumed that carbon
fibers are rigid as compared with glass fibers and other fibrous
reinforcing agents and resist bending distortion when a bending
load is imposed thereon, and hence they part from polyolefin
surfaces.
[0021] With this being the situation, by molding a resin
composition containing e.g. 4 ingredients, a polyolefin, carbon
fibers, a polyamide and a compatibilizer, the resin molding
obtained comes to have excellent mechanical strengths, notably in
point of bending elasticity modulus.
[0022] In a resin composition containing a polyolefin, carbon
fibers, a polyamide and a compatibilizer, when the carbon fibers in
the resin composition include only short fibers (having e.g. an
average fiber length of 1 mm or below), there may be cases where
resin moldings made from such a resin composition suffer reduction
in impact resistance.
[0023] For instance, in a resin composition containing carbon
fibers, because of their rigidity, the carbon fibers are apt to
suffer breakage under a mechanical load imposed during the process
of melt-kneading carbon fibers and a polyolefin. As a result, the
carbon fibers in the resin composition are apt to be reduced in
fiber length (e.g. so as to have an average fiber length of 1 mm or
below).
[0024] Thus, as to the composition containing a polyolefin, carbon
fibers, a polyamide and a compatibilizer, it has been learned that
a resin molding formed from the resin composition whose carbon
fibers are only carbon fibers changed into short fibers by a
mechanical load imposed during the process of melt-kneading the
carbon fibers and the polyolefin, though inhibited from reduction
in its bending elasticity modulus, has a tendency to be susceptible
to reduction in impact resistance.
[0025] This phenomenon is considered as follows. Because the carbon
fibers in a resin molding are changed into those having short
lengths, entanglement of carbon fibers is presumed to be limited in
the resin molding. Therefore it is presumed that, when an impact
force is imposed on the resin molding, the impact force is
difficult to diffuse through the interior of the resin molding to
result in breakage of the resin molding.
[0026] In contrast, the resin composition relating to an embodiment
of the invention has the constitution as mentioned above, and
thereby resin moldings obtained therefrom are improved in impact
resistance. A reason for this improvement remains uncertain, but
they are considered as follows.
[0027] In the resin composition relating to an embodiment of the
invention, the first resin composition contains the first carbon
fibers having an average fiber length of 0.1 mm to 1 mm, and the
second resin composition contains the second carbon fibers having
an average fiber length of 6 mm to 20 mm. In a resin molding
obtained using this resin composition, carbon fibers long in fiber
length are included as a portion of all the carbon fibers in
addition to carbon fibers changed into those short in fiber length.
More specifically, the carbon fibers are e.g. in a state that the
average fiber length of all the carbon fibers including carbon
fibers short in fiber length and carbon fibers long in fiber length
is from 0.2 mm to 1 mm and the percentage by number of long carbon
fibers from 1 mm to 20 mm in fiber length to all the carbon fibers
is from 1% to 20%.
[0028] In this state, even when an impact force is imposed on the
resin molding, the impact force is presumed to diffuse easily
through the interior of the resin molding. Therefore the resin
molding formed through the use of the resin composition having the
constitution mentioned above is presumed to get improved
impact-resisting strength.
[0029] As mentioned above, the resin composition relating to this
embodiment allows, in a resin molding formed therefrom, presence of
carbon fibers having undergone fiber-length shortening and carbon
fibers partially including long fibers, and therefore it is
presumed that the resin molding improved in impact resisting
strength is obtained.
[0030] By the way, for the purpose of improving impact resistance,
it may be considered to use a resin composition containing only
long fibers (for example, 6 mm or above) in average fiber length.
However, in the case of producing a resin molding through the use
of a resin composition in which the carbon fibers are only carbon
fibers long in fiber length, though the carbon fibers are broken
through the application of a load thereto in the interior of
molding apparatus, entanglement of long fibers tends to occur in
the molten resin composition. Therefore the resin composition in a
molten state becomes low in flowability, and the moldability
thereof tends to be reduced.
[0031] In contrast, even though the resin composition relating to
an embodiment of the invention includes the second resin
composition containing the second carbon fibers having an average
fiber length of 6 mm to 20 mm, reduction in flowability of the
resin composition in a molten state is inhibited. On the occasion
of producing a resin molding through the use of the resin
composition relating to an embodiment of the invention, the resin
composition undergoes hot melting. It is presumed that, by
containing the first carbon fibers having an average fiber length
of 0.1 mm to 1 mm in the resin composition in a molten state,
entanglement of the second carbon fibers having an average fiber
length of 6 mm to 20 mm is inhibited. Accordingly, it is thought
that the resin composition relating to an embodiment of the
invention is inhibited from receiving reduction in the flowability
when it is in a molten state. Thus the resin composition relating
to an embodiment of the invention is superior also in
moldability.
[0032] Herein, a resin molding obtained using the resin composition
relating to an embodiment of the invention is also inhibited from
receiving reduction in bending elasticity modulus. Although an
action bringing about such an effect remains unclear, it is thought
as follows.
[0033] On the occasion of producing a resin molding from the resin
composition which relates to an embodiment of the invention and
includes the first resin composition and the second resin
composition, the resin composition is subjected to hot-melt mixing,
and thereby the polyolefin as a matrix and the compatibilizer are
molten together, and besides the polyamide becomes compatible with
the compatiblizer through a portion of the interior of
compatibilizer molecules and amide or imide bonds present in
polyamide molecules, resulting in dispersion into the resin
composition.
[0034] By the way, the term polyamide as used in this specification
is intended to include not only resins having amide bonds in their
individual main chains but also resins having both amide bonds and
imide bonds in their individual main chains (referred to as the
so-called polyamide imide).
[0035] In the state described above, when polyamide molecules come
into contact with carbon fibers (including the first carbon fibers
and the second carbon fibers), amide bonds or imide bonds present
in large numbers along the molecular chains of polyamide and polar
groups present in small numbers on carbon fiber surfaces are
physically coupled together at multiple sites by dint of affinity
(gravitation and hydrogen bonding). In addition, because not only
compatibility of polyolefin with carbon fiber but also affinity of
polyolefin for carbon fiber is generally low, repulsive force is
created between polyolefin and polyamide as well as between
polyolefin and carbon fiber, and thereby frequency of contact
between polyamide and carbon fiber is increased, resulting in
formation of domains of carbon fiber-polyamide composites in the
polyolefin matrix. Consequently, the amount and area of polyamide
bonded to carbon fibers are increased. Thus a covering layer of
polyamide is formed around the periphery of carbon fiber (see FIG.
1). By the way, PP, CF and CL in FIG. 1 stand for polyolefin,
carbon fiber and covering layer, respectively.
[0036] Further, the polyamide forming a covering layer chemically
reacts with some of reactive groups in compatibilizer molecules,
and electrostatic interactions occur between polar groups in these
ingredients, and thereby the polyamide comes to have compatibility
with the compatibilizer, and besides the compatibilizer is also
compatible with polyolefin. Thus an equilibrium state is created
between gravitational and repulsive forces to result in formation
of a polyamide covering layer in a thin and uniform state. Because
affinity of carboxyl groups present on the carbon fiber surfaces
for amide bonds or imide bonds present in polyamide molecules is
especially high, it is presumed that a covering layer of polyamide
is more likely to be formed around the peripheries of carbon
fibers, and the covering layer formed is thin and superior in
uniformity.
[0037] In addition, the covering layer preferably covers all over
the carbon fiber surface, but an uncovered portion may be present
on the carbon fiber surface.
[0038] As mentioned above, the resin composition relating to an
embodiment of the invention allows improvement in adhesion of the
carbon fiber-polyolefin interface. Consequently, it is considered
that resin moldings obtained from the resin composition relating to
an embodiment of the invention is superior in mechanical strengths,
notably in bending elasticity modulus.
[0039] As to the resin composition relating to an embodiment of the
invention and including the first resin composition and the second
resin composition and resin moldings obtained from such a resin
composition, a covering layer of polyamide is formed around the
peripheries of carbon fibers through the hot-melt kneading during
the preparation for the first resin composition (in the form of
e.g. pellets) and injection molding of the resin composition, and
the covering layer formed preferably has a structure from 5 nm to
700 nm in thickness.
[0040] In the resin composition relating to an embodiment of the
invention, the covering layer of polyamide is from 5 nm to 700 nm
in thickness, and from the viewpoint of further improving the
bending elasticity modulus, the thickness thereof is preferably
from 10 nm to 650 nm. The covering layer thickness of 5 nm or above
(notably 10 nm or above) allows improvement in bending elasticity
modulus, while the covering layer thickness of 700 nm or below
makes it possible to inhibit the interface between carbon fiber and
polyolefin through the medium of polyamide from becoming fragile,
thereby controlling reduction in bending elasticity modulus.
[0041] The thickness of the covering layer is a value determined by
the following method. A subject of measurement is ruptured in
liquid nitrogen, and a cross section thereof is observed an
electron microscope (VE-9800, made by KEYENCE CORPORATION). On the
cross section, thickness measurements are made at 100 points of
covering layers covering around the peripheries of carbon fibers,
and the average of these measurement values is calculated.
[0042] By the way, checking of the covering layers is carried out
by the cross section observation mentioned above.
[0043] Additionally, the first resin composition included in the
resin composition relating to an embodiment of the invention and a
resin molding molded from the resin composition relating to an
embodiment of the invention and including the first resin
composition and the second resin composition have structure that
the compatibilizer performs partial compatibilization between the
covering layer and the polyolefin.
[0044] To be specific, it is appropriate that there be a layer of
compatibilizer e.g. between the polyamide covering layer and the
polyolefin as a matrix (see FIG. 1). In other words, it is
appropriate that an intervening layer of the compatibilizer be
formed on the surface of the covering layer and the covering layer
be adjacent to the polyolefin through the layer of the
compatibilizer. The layer of the compatibilizer is formed in a
smaller thickness than the covering layer, and the adhesion
(bonding) of the covering layer to the polyolefin is enhanced by
the medium of the compatibilizer layer, and thereby it becomes easy
to obtain a resin molding superior in mechanical strengths, notably
in bending elasticity modulus. By the way, PP, CF, CL and CA in
FIG. 1 stand for polyolefin, carbon fiber, covering layer and
compatibilizer, respectively.
[0045] It is especially appropriate that the compatibilizer layer
be present between the covering layer and the polyolefin in a state
of bonding to the covering layer (through hydrogen bonds and
covalent bonds formed by reaction between functional groups of the
compatibilizer and the polyamide) and being compatible with the
polyolefin. Such a constitution is easy to realize by adopting a
compatibilizer which has e.g. the same structure as the polyolefin
matrix or a structure allowing compatibility with the polyolefin,
and besides which contains in a portion of its molecule such a
moiety as to react with the above-cited functional groups of the
polyamide.
[0046] More specifically, in the case of adopting e.g. a
polyolefin, a polyamide and a maleic anhydride-modified polyolefin
as a compatibilizer, it is appropriate that a layer of the maleic
anhydride-modified polyolefin (a layer of the compatibilizer) be
present in a state that the carboxyl groups formed by ring-opening
of maleic anhydride moieties react with amine residues of the
polyamide layer (covering layer) to bond these layers together and
compatibilize such polyolefin moieties and the polyolefin.
[0047] Now, a method for checking the presence of a compatibilizer
layer between the covering layer and the polyolefin is as
follows.
[0048] An infrared microspectroscopic analyzer (IRT-5200, made by
JASCO Corporation) is used as an analysis device. For example, a
sliced piece is cut from a resin molding which includes
polypropylene (PP) as a polyolefin, PA66 as a polyamide and maleic
anhydride-modified polyolefin (MA-PP) as a modified polyolefin, and
a cross section thereof is observed. IR mapping of covering layer
portions around the cross sections of carbon fibers is carried out,
thereby checking on covering layer-maleic anhydride of
compatibilizer layer origin (1,820 cm.sup.-1 to 1,750 cm.sup.-1).
By doing so, the presence of a compatibilizer layer between the
covering layer and the polyolefin can be ascertained. More
specifically, when reaction occurs between MA-PP and PA66, cyclic
maleated portion of MA-PP undergoes ring opening, and thereby
chemical bonding of the amine residues of PA66 takes place to
reduce the cyclic maleated portion. Thus the presence of a
compatibilizer layer (bonding layer) between the covering layer and
the polyolefin can be ascertained.
(First Resin Composition and Second Resin Composition)
[0049] The resin composition relating to an embodiment of the
invention, as mentioned above, has the first resin composition
containing a first polyolefin, a polyamide, first carbon fibers and
a compatibilizer, and besides it has the second resin composition
containing a second polyolefin and second carbon fibers.
[0050] Additionally, it is appropriate that each of the first resin
composition and the second resin composition be a non-crosslinked
resin composition.
[0051] Herein, the second resin composition may consist of two
ingredients, a second polyolefin and second carbon fibers, or it
may contain, in addition to these two ingredients, at least either
a second polyamide or a carboxylic anhydride-modified polyolefin as
a second compatibilizer.
[0052] In the resin composition relating to an embodiment of the
invention, the ratio (by mass) between the first resin composition
and the second resin composition has no particular limits. The
ratio between these two resin compositions may be determined so
that, taking the total content of the first polyolefin and the
second polyolefin as 100 parts by mass, referred to the whole
quantity of the resin composition, the polyamide content falls
within a range of 1 part by mass to 50 parts by mass, the total
content of the first carbon fibers and the second carbon fibers
falls within a range of 1 part by mass to 50 parts by mass and the
compatibilizer content falls within a range of 1 part by mass to 10
parts by mass.
[0053] As to the ratio between the first resin composition content
and the second resin composition content, depending on the
ingredients of the first resin composition and those of the second
resin compositions, when the first resin composition content of the
whole resin composition is symbolized by W1 and the second resin
composition content of the whole resin composition is symbolized by
W2, the W1/W2 ratio by mass is e.g. W1/W2=1/99 to 99/1 (preferably
from 90/10 to 90/10).
[0054] In point of improvement in impact resistance of a resin
molding to be formed, it is appropriate that the proportion of each
of ingredients, a first polyolefin, a polyamide, first carbon
fibers and a compatibilizer, in the first resin composition be
within a range as specified below.
[0055] It is appropriate that the polyolefin content of the first
resin composition account for e.g. from 5 mass % to 95 mass %
(preferably from 10 mass % to 95 mass %, more preferably from 20
mass % to 95 mass %) of the total mass of the first resin
composition.
[0056] It is appropriate that the polyamide content of the first
resin composition be from 0.1 parts by mass to 100 parts by mass
(preferably from 0.5 parts by mass to 90 parts by mass, more
preferably from 1 part by mass to 80 pars by mass) with respect to
100 parts by mass of the polyolefin.
[0057] It is appropriate that the first carbon fiber content of the
first resin composition be from 0.1 parts by mass to 200 parts by
mass (preferably from 1 part by mass to 180 parts by mass, more
preferably from 5 parts by mass to 150 pars by mass) with respect
to 100 parts by mass of the polyolefin.
[0058] It is appropriate that the compatibilizer content of the
first resin composition be from 0.1 parts by mass to 50 parts by
mass (preferably from 0.1 parts by mass to 40 parts by mass, more
preferably from 0.1 parts by mass to 30 pars by mass) with respect
to 100 parts by mass of the polyolefin.
[0059] Further, it is appropriate in point of improvement in impact
resistance of a resin molding to be formed that the proportion of
each of ingredients, a second polyolefin and second carbon fibers,
in the second resin composition be within a range as specified
below.
[0060] It is appropriate that the polyolefin content of the second
resin composition account for e.g. from 40 mass % to 90 mass %
(preferably from 50 mass % to 80 mass %) of the total mass of the
second resin composition.
[0061] It is appropriate that the second carbon fiber content of
the second resin composition be from 11 parts by mass to 150 parts
by mass (preferably from 25 parts by mass to 100 parts by mass)
with respect to 100 parts by mass of the polyolefin.
[0062] In point of improvement in impact resistance of a resin
molding to be formed, it is appropriate that the ratio (by mass)
between the first carbon fiber content of the first resin
composition and the second carbon fiber content of the second resin
composition fall within the range as specified below. When the
first carbon fiber content and the second carbon fiber content with
respect to the whole quantity of the resin composition for a resin
molding are symbolized by CF1 and CF2, respectively, it is
appropriate that the ratio by mass between CF1 and CF2 (CF1/CF2
ratio) be from at least CF1/CF2=10/90 to at most CF1/CF2=90/10
(preferably from at least 10/90 to at most 50/50).
(Manufacturing Method of Resin Composition)
[0063] The first resin composition is manufactured by a method in
which a first polyolefin, a polyamide, carbon fibers cut down to an
intended length and a compatibilizer are subjected to melt
kneading.
[0064] Herein, publicly-known systems can be used as melt kneading
instruments, with examples including a twin-screw extruder, a
Henschel mixer, a B anbury mixer, a single-screw extruder, a
multi-screw extruder and a co-kneader.
[0065] The temperature during the melt kneading (cylinder
temperature) may be determined in response to the melting
temperatures of resinous ingredients and the like included in the
resin composition.
[0066] It is preferred that the first resin composition in
particular be obtained by a manufacturing method including the
process of subjecting a polyolefin, a polyamide, carbon fibers cut
down to an intended length and a compatibilizer to melt kneading.
When a set of polyolefin, polyamide and carbon fibers cut down to
the intended length and compatibilizer is melt-kneaded as a single
unit, a covering layer of the polyamide in a thin and nearly
uniform state tends to be formed around the periphery of each
individual carbon fiber, thereby allowing improvements in
mechanical strengths, notably in bending elasticity modulus.
[0067] As an example of a method for manufacturing the second resin
composition, mention may be made of a method in which a second
polyolefin and long-length carbon fibers cut down to an intended
length are subjected to melt kneading. As another example, mention
may be made of a method in which, while the carbon fibers in
continuous fiber form (known as roving) are subjected to opening,
the surfaces thereof are impregnated and coated with a molten
polyolefin resin, and the thus processed carbon fibers are pulled
out (a pultrusion process). From the viewpoint of inhibiting
breakage of the carbon fibers, it is preferred that the second
resin composition in particular be manufactured through the use of
such a pultrusion process.
[0068] As an example of a pultrusion process, mention may be made
of a publicly-known method. To be more specific, in such a method,
carbon fibers in continuous fiber form are impregnated and coated
with a molten polyolefin by means of e.g. a cross-head die. After
solidification by cooling, the resulting carbon fibers are cut down
to an intended length, and thereby made into the second resin
composition.
[0069] By using any of the foregoing methods is obtained a resin
composition which relates to an embodiment of the invention and
includes the first resin composition and the second resin
composition. By the way, the resin composition relating to an
embodiment of the invention may be a composition obtained by mixing
the first resin composition and the second resin composition, or it
may also be a composition obtained by mixing the first resin
composition and the second resin composition, and then melting both
the first resin composition and the second resin composition.
(Constitution of Resin Composition)
[0070] In the next place, proportions of individual ingredient
contents in the whole quantity of the resin composition are
described.
[0071] The resin composition relating to an embodiment of the
invention has, as mentioned above, ingredient contents in their
respective proportions specified below in the whole quantity of the
resin composition including the first resin composition and the
second resin composition.
[0072] With respect to 100 parts by mass of total content of the
first polyolefin and the second polyolefin, the polyamide content
is from 1 part by mass to 50 parts by mass, the total content of
the first carbon fibers and the second carbon fibers is from 1 part
by mass to 50 parts by mass, and the content of a carboxylic
anhydride-modified polyolefin as a compatibilizer is from 1 part by
mass to 10 parts by mass.
[0073] The percentage of polyolefin content (total for a first
polyolefin content and a second polyolefin content) to the whole
mass of resin composition may be determined in response to uses of
a resulting resin molding. For example, the polyolefin content
accounts for preferably 5 mass % to 95 mass %, more preferably 10
mass % to 95 mass %, still more preferably 20 mass % to 95 mass %,
of the total mass of resin composition.
[0074] The carbon fiber content (the total for first carbon fiber
content and second carbon fiber content) is from 1 part by mass to
50 parts by mass, preferably from 10 parts by mass to 50 parts by
mass, more preferably from 20 parts by mass to 40 parts by mass,
with respect to 100 parts by mass of polyolefin content.
[0075] By containing carbon fibers in a proportion of at least 1
part by mass to 100 parts by mass of polyolefin, the resin
composition aims reinforcement, and by adjusting the carbon fiber
content to 50 parts by mass or below with respect to 100 parts by
mass of polyolefin, good moldability is achieved at the time of
obtaining a resin molding.
[0076] By the way, in the case of using the other fibrous
reinforcing agent in addition to carbon fibers, it is preferred
that the carbon fibers account for at least 90 mass % of the total
mass of carbon fibers and the other fibrous reinforcing agent.
[0077] Hereafter, a content (by mass) with respect to 100 parts by
mass of polyolefin is abbreviated as phr (per hundred resin) in
some cases.
[0078] Using this abbreviation, the above phrase is expressed as
"carbon fiber content is from 1 phr to 50 phr".
[0079] The polyamide content is from 1 part by mass to 50 parts by
mass with respect to 100 parts by mass of polyolefin. From the
viewpoint of further enhancing impact resistance, the polyamide
content is preferably from 2 parts by mass to 40 parts by mass,
more preferably from 5 parts by mass to 30 parts by mass.
[0080] By adjusting the polyamide content to fall within the above
range, the affinity for the carbon fibers is increased, and
enhancement of impact resistance is aimed at.
[0081] In the special case of containing a polyamide in a large
amount ranging from larger than 20 parts by mass to no larger than
50 parts by mass with respect to 100 parts by mass of polyolefin,
the compatibilizer content relative to the polyamide content
becomes low, and thereby it becomes difficult for the polyamide to
diffuse into the polyolefin matrix and a tendency for the polyamide
to localize around the peripheries of carbon fibers is intensified.
Thus it is thought that a covering layer of polyamide is formed in
a somewhat-thickened and nearly-uniform state all over the
peripheries of the carbon fibers having short fiber lengths.
Therefore adhesion at the interfaces between polyolefin and carbon
fibers is enhanced, and it becomes easy to obtain a resin molding
superior in mechanical strengths, notably in impact resistance.
[0082] From the viewpoint of allowing an affinity of polyamide for
carbon fibers to manifest itself effectively and increasing
flowability of the resin composition, it is preferred that the
polyamide content be proportioned to the foregoing carbon fiber
content.
[0083] The compatibilizer content is from 1 part by mass to 10
parts by mass, preferably from 1 part by mass to 8 parts by mass,
more preferably from 1 part by mass to 5 parts by mass, with
respect to 100 parts by mass of polyolefin.
[0084] By adjusting the compatibilizer content to fall within the
above range, the affinity between polyolefin and polyamide is
enhanced, and thereby improvement in impact resistance is aimed
at.
[0085] From the viewpoint of enhancing the affinity between
polyolefin and polyamide, it is preferred that the compatibilizer
content be proportioned to the polyamide content (and be
proportioned indirectly to the carbon filter content).
[0086] Each of ingredients in the resin composition relating to an
embodiment of the invention is described below in detail.
-Polyolefin-
[0087] The resin composition which relates to an embodiment of the
invention and is used for resin moldings contains a first
polyolefin in the first resin composition and a second polyolefin
in the second resin composition.
[0088] The first polyolefin and the second polyolefin may be the
same as or different from each other, but they are preferably the
same. In addition, as each of polyolefin for the first polyolefin
and that for the second polyolefin, only one kind may be used or
two or more kinds of polyolefin may be used in combination.
[0089] Hereafter, as to particulars common to the first polyolefin
and the second polyolefin, explanation is made by simply using the
term polyolefin so long as there is no need to make a distinction
between them.
[0090] Polyolefin is a matrix of the resin composition, and refers
to the resinous ingredient to be reinforced by carbon fibers (which
is also referred to as a matrix resin).
[0091] Polyolefin is a resin containing repeating units of olefin
origin, and the resin may contain repeating units derived from a
monomer other than olefins so long as the other repeating units
constitute at most 30 mass % of the whole resin.
[0092] Polyolefin is produced by addition polymerization of an
olefin (and, if necessary, a monomer other than olefins).
[0093] In addition, each of the olefin and the monomer other than
olefins for use in production of polyolefin may be only one kind or
a combination of two or more kinds.
[0094] By the way, the polyolefin may be either a homopolymer or a
copolymer. Additionally, the polyolefin may have the form of either
a straight chain or a branched chain.
[0095] Examples of such olefins include straight-chain or
branched-chain aliphatic olefins and alicyclic olefins.
[0096] Examples of aliphatic olefins include a-olefins, such as
ethylene, propylene, 1-butene, 1-hexene, 4-methyl-1-pentene,
1-octene, 1-decene, 1-hexadecene and 1-octadecene.
[0097] On the other hands, examples of alicyclic olefins include
cyclopentene, cyclobutene, cycloheptene, norbornene,
5-methyl-2-norbornene, tetracyclododecene and vinylcyclohexene.
[0098] Of these olefins, in point of cost, a-olefins are preferable
to the others, ethylene and propylene are far preferred, and
propylene is especially preferred.
[0099] Also, well-known addition-polymerizable compounds are
selected as a monomer other than olefins.
[0100] Examples of the addition-polymerizable compound include
styrene compounds, such as styrene, methylstyrene, a-methylstyrene,
.beta.-methylstyrene, t-butylstyrene, chlorostyrene,
chloromethylstyrene, methoxystyrene and styrene sulfonic acid or
salts thereof; (meth)acrylic esters, such as alkyl (meth)acrylates,
benzyl (meth)acrylate and dimethylaminoethyl (meth)acrylate;
halovinyl compounds, such as vinyl chloride; vinyl esters such as
vinyl acetate and vinyl propionate; vinyl ethers, such as vinyl
methyl ether; halogenated vinylidene compounds, such as vinylidene
chloride; and N-vinyl compounds, such as N-vinylpyrrolidone.
[0101] Examples of a suitable polyolefin include polypropylene
(PP), polyethylene (PE) and ethylene-vinyl acetate copolymer resin
(EVA). It is appropriate that the polyolefin be at least one kind
selected from the group consisting of polypropylene (PP),
polyethylene (PE) and ethylene-vinyl acetate copolymer resin
(EVA).
[0102] Among the olefin polymers recited above, resins each
containing only repeating units of olefin origin are preferred over
the others, and polypropylene is especially preferred in point of
cost.
[0103] The molecular weight of polyolefin is not particularly
limited, and it may be determined in response to the kind of resin
used, molding conditions, uses of resulting resin moldings and so
on. For example, the weight-average molecular weight (Mw) of
polyolefin is preferably in a range of 10,000 to 300,000, more
preferably in a range of 10,000 to 200,000.
[0104] In addition, the glass transition temperature (Tg) or
melting temperature (Tm) of polyolefin is not particularly limited
as is the case with the molecular weight, and it may be determined
in response to the kind of resin used, molding conditions, uses of
resulting resin moldings and so on. For example, the melting
temperature (Tm) of polyolefin is preferably in a range of
100.degree. C. to 300.degree. C., more preferably in a range of
150.degree. C. to 250.degree. C., still more preferably in a range
of 150.degree. to 200.degree. C. , most preferably in a range of
160.degree. C. to 190.degree. C.
[0105] By the way, the weight-average molecular weight (Mw) and
melting temperature (Tm) of polyolefin are values determined as
follows.
[0106] Specifically, the weight-average molecular weight (Mw) of
polyolefin is determined by using gel permeation chromatography
(GPC) under the following conditions. A high-temperature GPC system
HLC-8321GPC/HT is used as GPC apparatus and o-dichlorobenzene is
used as an eluent. A polyolefin is once molten in o-dichlorobenzene
and filtered at a high temperature (a temperature in a range of
140.degree. C. to 150.degree. C.), and the filtrate thus obtained
is adopted as a measurement sample. As to the measurement
conditions, the sample concentration is 0.5%, the flow rate is 0.6
ml/min, the injected sample volume is 10 .mu.1, and the measurement
is made with an RI detector. In addition, the calibration curve is
prepared using 10 polystyrene standard samples produced by TOSOH
CORPORATION, TSK standard A-500, F-1, F-10, F-80, F-380, A-2500,
F-4, F-40, F-128 and F-700.
[0107] On the other hand, the melting temperature (Tm) of
polyolefin is determined from the DSC curve obtained by
differential scanning calorimetry (DSC) as "melting peak
temperature" described in JIS K 7121-1987, directions for
determination of melting temperature in "methods for measuring
transition temperature of plastic".
-Carbon Fiber-
[0108] The resin composition relating to an embodiment of the
invention contains first carbon fibers having an average fiber
length of 0.1 mm to 1 mm in the first resin composition and second
carbon fibers having an average fiber length of 6 mm to 20 mm in
the second resin composition.
[0109] The average fiber length of first carbon fibers is
preferably from 0.1 mm to 0.8 mm, more preferably from 0.2 mm to
0.7 mm.
[0110] The average fiber length of second carbon fibers is
preferably from 8 mm to 20 mm, more preferably from 10 mm to 20
mm.
[0111] Now, there is provided explanation of a method for measuring
fiber lengths of the first carbon fibers and the second carbon
fibers included in the resin composition and fiber lengths of
carbon fibers included in a resin molding described later.
[0112] To begin with, a subject for measurement, namely a resin
composition or a resin molding, is put in an aluminum crucible, and
fired at 500.degree. C. for 2 hours by means of a Muffle furnace.
After firing, the carbon fibers remaining in the crucible are
collected, and dispersed into a 0.1% water solution of surfactant.
Photographs of the carbon fibers are taken by using a digital
microscope (VHX-100, made by KEYENCE CORPORATION) under a
measurement magnification of 10. The fiber lengths of carbon fibers
are measured using image analysis software (WINROOF2015, produced
by MITANI CORPORATION). And this fiber-length measurement is made
on 200 carbon fibers, and the average value of fiber lengths thus
measured is taken as an average fiber length of carbon fibers. By
the way, the fiber length of carbon fibers is a number-average
fiber length.
[0113] As the first carbon fibers used when the first resin
composition is prepared, carbon fibers having an average fiber
length of e.g. 0.1 mm to 5.0 mm are suitable. For example, carbon
fibers having an average fiber length of 0.1 mm to 1 mm may be
used, or those having an average fiber lengths of 1 mm to 5 mm may
be used. Even when carbon fibers have an average fiber length of 1
mm to 5 mm, they may be used if only the average fiber length is
adjusted to fall within the range of 0.1 mm to 1 mm during the
melt-kneading process.
[0114] When the average fiber length of the first carbon fibers in
the first resin composition is in the above range, reduction in
flowability at the time of melting the resin composition is
inhibited. Further, reduction in bending elasticity modulus of a
resulting resin molding is also inhibited.
[0115] The second carbon fibers incorporated into the second resin
composition have no particular restrictions so long as their
average fiber length is in a range of 6 mm to 20 mm. As the second
carbon fibers, in point of improvement in impact resistance of a
resulting resin molding, it is appropriate to use carbon fibers of
the type which is produced by Roving method and made up of great
many fibers in a converged state.
[0116] Hereafter, as to particulars common to the first carbon
fibers and the second carbon fibers, explanation is made by simply
using the term carbon fibers unless noted otherwise.
[0117] As the carbon fibers, publicly-known carbon fibers are used,
and any of PAN-based carbon fibers and pitch-based carbon fibers
may be used.
[0118] The carbon fibers may be those having undergone
publicly-known surface treatment.
[0119] Examples of surface treatment for carbon fibers include
oxidizing treatment and sizing treatment.
[0120] As the carbon fibers, commercially available products may be
used. Examples of a commercially available PAN-based carbon fiber
product include TORAYCA.RTM., produced by Toray Industries, Inc.,
Tenax produced by Toho Tenax, and Pyrofil.RTM., produced by
Mitsubishi Chemical Corporation. In addition thereto, commercially
available PAN-based carbon fiber products include products from
Hexcel Corporation, those from Cytec Industries, Inc., those from
DowAksa, those from Formosa Plastics Corporation, those from SGL
and so on.
[0121] Examples of a commercially available pitch-based carbon
fiber product include DIALEAD.RTM. produced by Mitsubishi Chemical
Corporation, GRANOC produced by Nippon Graphite Fiber Co., Ltd.,
and KURECA produced by KUREHA CORPORATION. In addition thereto,
commercially available pitch-based carbon fiber products include
products from Osaka Gas Chemicals Co., Ltd., those from Cytec
Industries, Inc. and so on.
[0122] By the way, only one kind of carbon fibers may be used, or
two or more different kinds of carbon fibers may be used in
combination.
[0123] The carbon fibers have no particular limits on their fiber
diameter and so on, and the fiber diameter may be chosen according
to the uses of a resulting resin molding. The average fiber
diameter of carbon fibers may be e.g. from 5.0 .mu.m to 10.0 .mu.m
(preferably from 6.0 .mu.m to 8.0 .mu.m).
[0124] Herein, the average fiber diameter of carbon fibers is
determined in the following manner. A cross section orthogonal to
the length direction of each individual carbon fiber is observed
under an SEM (a scanning electron microscope) set at a
magnification of 1,000, and the diameter of each individual carbon
fiber is measured. This measurement is made on 100 carbon fibers,
and the average of measured values is calculated and defined as the
average diameter of carbon fibers.
-Polyamide-
[0125] Polyamide is a resin having amide bonds. The polyamide
include a resin having amide bonds in one and the same main chain
thereof and a resin having imide bonds as well as amide bonds in
one and the same main chain thereof.
[0126] Such polyamide is illustrated below in detail.
[0127] The polyamide is preferably a resin low in compatibility
with polyolefin, and more specifically, a resin different in
solubility parameter (SP value) from polyolefin.
[0128] Herein, the SP value difference between polyolefin and
polyamide is preferably at least 3, more preferably from 3 to 6,
from the viewpoints of compatibility between these polymers and
repulsive force between both.
[0129] The SP value mentioned herein is a value estimated by the
Fedors method. More specifically, the solubility parameter (SP
value) conforms e.g. to the description in Polymer. Eng._Sci., vol.
14, p.147 (1974), and it is determined by the following
expression.
Expression: SP value= (Ev/v)=
(.SIGMA..DELTA.ei/.SIGMA..DELTA.vi)
(In the expression, Ev is evaporation energy (cal/mol), v is molar
volume (cm.sup.3/mol), .DELTA.ei is evaporation energy of each
individual atom or atomic group and .DELTA.vi is molar volume of
each individual atom or atomic group).
[0130] By the way, (cal/cm.sup.3).sup.1/2 is adopted as a unit of
solubility parameter (SP value), but herein the unit is omitted
according to established practice and dimensionless notation is
used.
[0131] In addition, the polyamide has amide bonds in its
molecule.
[0132] By virtue of presence of amide bonds in polyamide, an
affinity develops between the polyamide and polar groups present on
the surface of carbon fiber.
[0133] As one among concrete kinds of the polyamide, there is a
thermoplastic resin containing amide bonds in its main chain, and
examples thereof include polyamide (PA), polyamide imide (PAI) and
polyamino acid.
[0134] The polyamide has no particular restrictions, but from the
viewpoints of further enhancement of impact resistance and
excellent adhesion to carbon fibers, polyamide (PA) is
preferred.
[0135] Examples of the polyamide include polyamide produced by
copolycondensation of dicarboxylic acid and diamine and polyamide
produced by condensation of lactam. More specifically, the
polyamide is e.g. a polyamide having at least either structural
units formed by polycondensation of dicarboxylic acid and diamine
or structural units formed by ring-opening of lactam.
[0136] When polyamide having aromatic ring-containing structural
units except aramide structural units and aromatic ring-free
structural units is utilized as the polyamide, the polyamide can
have good affinities for both of carbon fiber and polyolefin. Now,
polyamide having only aromatic ring-containing structural units
tends to be high in affinity for carbon fiber and low in affinity
for polyolefin as compared with polyamide having only aromatic
ring-free structural units. Polyamide having only aromatic
ring-free structural units tends to be low in affinity for carbon
fiber and high in affinity for polyolefin as compared with
polyamide containing only aromatic ring-containing structural
units. On this account, utilization of polyamide having both of
these structural units ensures good affinities for both carbon
fiber and polyolefin, and a covering layer formed of such a
polyamide allows further enhancement of adhesion at the interface
between carbon fiber and polyolefin. Therefore resin moldings
superior in mechanical strengths, notably in impact resistance,
become easy to obtain.
[0137] In addition, utilization of polyamide having both aromatic
ring-containing structural units and aromatic ring-free structural
unit conduces to not only reduction in melt viscosity but also
improvement in moldability (e.g. injection moldability).
Accordingly, resin moldings high in outward appearance quality
become easy to obtain.
[0138] On the other hand, utilization of polyamide having only
aramide structural units brings about thermal degradation of
polyolefin at high temperatures allowing fusion of the polyamide.
Moreover, satisfactory fusion of the polyamide does not occur at
temperatures causing thermal degradation of polyolefin, resulting
in deterioration of moldability (e.g. injection moldability) and
reductions in outward appearance quality and mechanical performance
of resin moldings to be produced.
[0139] By the way, the term aromatic ring used herein is intended
to include 5- or more-membered monocyclic aromatic rings (e.g.
cyclopentadiene, benzene) and fused rings (e.g. naphthalene) formed
by fusing together two or more 5- or more-membered monocyclic
aromatic rings. The aromatic rings include heterocyclic rings (e.g.
pyridine) also.
[0140] In addition, the aramide structural unit refers to the
structural unit formed by polycondensation reaction between an
aromatic ring-containing dicarboxylic acid and an aromatic
ring-containing diamine.
[0141] The aromatic ring-containing structural unit except the
aramide structural unit includes e.g. at least either of the
following structural units (1) and (2).
Structural unit (1): --(--NH--Ar.sup.1--NH--CO--R.sup.1--CO--)--
(where Ar.sup.1 represents a divalent organic group which contains
an aromatic ring, and R.sup.1 represents a divalent organic group
which is free of an aromatic ring) Structural unit (2):
--(--NH--R.sup.2--NH--CO--Ar.sup.e--CO--)-- (where Ar.sup.e
represent a divalent organic group which contains an aromatic ring,
and R.sup.2 represents a divalent organic group which is free of an
aromatic ring)
[0142] On the other hand, the aromatic ring-free structural unit
includes e.g. at least either of the following structural units (3)
and (4).
Structural unit (3): --(NH--R.sup.31--NH--CO--R.sup.32--CO)--
(where R.sup.31 represent a divalent organic group which is free of
an aromatic ring, and R.sup.32 represents a divalent organic group
which is free of an aromatic ring) Structural unit (4):
--(--NH--R.sup.4--CO--)-- (where R.sup.4 represents a divalent
organic group which is free of an aromatic ring)
[0143] By the way, the divalent organic groups represented by
individual symbols in structural formulae (1) to (3) are organic
groups derived from divalent organic groups present in dicarboxylic
acids, diamines or lactams. To be more specific, the divalent
organic group which contains an aromatic ring and is represented
e.g. by Ar.sup.1 in the structural unit (1) refers to the residue
formed by removing two amino groups from diamine, and the divalent
organic group which is free of an aromatic group and represented
e.g. by R.sup.1 in the structural unit (1) refers to the residue
formed by removing two carboxyl groups from a dicarboxylic acid.
Additionally, the divalent organic group which is free of an
aromatic ring and represented e.g. by R.sup.4 in the structural
unit (4) refers to the organic group sandwiched between NH and CO
groups at the time of ring-opening of a lactam.
[0144] The polyamide may include a copolymerized polyamide.
Alternatively, the polyamide may be a mixed polyamide, or a
combination of a copolymerized polyamide with a mixed polyamide.
Among them, a mixed polyamide is preferred in point of improvements
in mechanical strengths, notably in impact resistance.
[0145] The copolymerized polyamide is a copolymerized polyamide
obtained by copolymerizing e.g. a polyamide having aromatic
ring-containing structural units except aramide structural units
and a polyamide having aromatic ring-free structural units.
[0146] The mixed polyamide is e.g. a mixed polyamide including an
aromatic ring-containing polyamide and an aromatic ring-free
polyamide.
[0147] In the copolymerized polyamide, a suitable ratio by mass
between aromatic polyamide and aliphatic polyamide (aromatic
polyamide/aliphatic polyamide) is from 20/80 to 99/1 (preferably
from 50/50 to 96/4) in point of further improvement in mechanical
strengths, notably in impact resistance.
[0148] In the mixed polyamide also, a suitable ratio by mass
between aromatic polyamide and aliphatic polyamide (aromatic
polyamide/aliphatic polyamide) is from 20/80 to 99/1 (preferably
from 50/50 to 96/4) in point of further improvement in mechanical
strengths, notably in impact resistance.
[0149] In the aromatic polyamide, a suitable proportion of aromatic
ring-containing structural units to all the structural units is 80
mass % or above (preferably 90 mass % or above, more preferably 100
mass %).
[0150] On the other hand, in the aliphatic polyamide, a suitable
proportion of aromatic ring-free structural units to all the
structural units is 80 mass % or above (preferably 90 mass % or
above, more preferably 100 mass %).
[0151] Examples of the aromatic polyamide include polycondensates
of aromatic ring-containing dicarboxylic acids and aromatic
ring-free diamines and polycondensates of aromatic ring-free
dicarboxylic acids and aromatic ring-containing diamines.
[0152] Examples of the aliphatic polyamide include polycondensates
of aromatic ring-free dicarboxylic acids and aromatic ring-free
diamines, and ring-opened polycondensates of aromatic ring-free
lactams.
[0153] Examples of the aromatic ring-containing dicarboxylic acid
include phthalic acids (such as terephthalic acid and isophthalic
acid) and biphenyl dicarboxylic acids.
[0154] Examples of the aromatic ring-free dicarboxylic acid include
oxalic acid, adipic acid, suberic acid, sebacic acid,
1,4-cyclohexanedicarboxylic acid, malonic acid, succinic acid,
glutaric acid, pimelic acid and azelaic acid.
[0155] Examples of the aromatic ring-containing diamine include
p-phenylenediamine, m-phenylenediamine, m-xylylenediamine,
diaminodiphenylmethane and diaminodiphenyl ether.
[0156] Examples of the aromatic ring-free diamine include
ethylenediamine, pentamethylenediamine, hexamethylenediamine,
nonanediamine, decamethylenediamine and 1,4-cyclohexanediamine.
[0157] Examples of the aromatic ring-free lactam include
c-caprolactam, undecanelactam and lauryllactam.
[0158] By the way, as each of the dicarboxylic acids, each of the
diamine or the lactam, one kind thereof may be used or two or more
kinds thereof may be used in combination.
[0159] Examples of the aromatic polyamide include MXD6 (a
polycondensate of adipic acid and m-xylylenediamine), nylon 6T (a
polycondensate of terephthalic acid and hexamethylenediamine) and
nylon 9T (a polycondensate of terephthalic acid and
nonanediamine).
[0160] Examples of a commercially available aromatic polyamide
product include MXD6 produced by Mitsubishi Gas Chemical Industry,
Inc., Genestar.RTM.: PA6T, produced by KURARAY CO., LTD.,
Genestar.RTM.: PAST, produced by KURARAY CO., LTD., and TY-502NZ:
PA6T, produced by TOYOBO CO., LTD.
[0161] Examples of the aliphatic polyamide include nylon 6
(ring-opened polycondensate of -caprolactam), nylon 11 (ring-opened
polycondensate of undecanelactam), nylon 12 (ring-opened
polycondensate of lauryllactam), nylon 66 (polycondensate of adipic
acid and hexamethylenediamine), nylon 610 (polycondensate of
sebacic acid and hexamethylenediamine) and nylon 612
(polycondensate of caprolactum (carbon number: 6) and lauryllactam
(carbon number: 12).
[0162] Examples of a commercially available aliphatic polyamide
product include Zytel.RTM.: 7331J (PA6), produced by Du Pont and
Zytel.RTM.: 101L (PA66), produced by Du Pont.
[0163] The proportion of aromatic rings in a polyamide (a
copolymerized polyamide or a mixed polyamide) is preferably from 1
mass % to 55 mass %, more preferably from 5 mass % to 50 mass %,
still more preferably from 10 mass % to 40 mass %, in point of
further enhancement of mechanical strengths, notably bending
elasticity modulus.
[0164] By the way, the proportion of aromatic rings in a mixed
polyamide is taken as a proportion of aromatic rings in the total
for aromatic polyamides and aliphatic polyamides.
[0165] The wording "the proportion of aromatic rings in a
polyamide" used herein refers to the proportion of the total for
monocyclic aromatic rings and fused rings produced by fusing
together monocyclic aromatic rings. In calculating the proportion
of aromatic rings in a polyamide, substituents attached to
monocyclic aromatic rings and fused rings produced by fusing
together monocyclic aromatic rings are excluded.
[0166] In other words, the proportion of aromatic rings in a
polyamide is determined from calculation of the molecular weight of
a structural unit produced by polycondensation of a dicarboxylic
acid and a diamine or the molecular weight of a structural unit
produced by ring-opening of a lactam and calculation of the
proportion (mass %) of molecular weight of aromatic rings (aromatic
rings after removing substituents therefrom in the case of having
substituents) present in such a structural unit to the molecular
weight of the structural unit containing the aromatic rings.
[0167] Then, proportions of aromatic rings in representative
polyamides are given below. The proportions of aromatic rings in
nylon 6 and nylon 66 which have no aromatic rings are both 0 mass
%. On the other hand, in the case of MXD6 having aromatic rings,
the proportion of aromatic rings is 30.9 mass % because it has an
aromatic ring --C.sub.6H.sub.4-- (molecular weight: 76.10) in each
individual structural unit. Likewise, in the case of nylon 9T, the
proportion of aromatic rings is 26.4 mass %. [0168] Nylon 6:
Structural unit with formula [--NH--(CH.sub.2).sub.5--CO--],
molecular weight of structural unit=113.16, proportion of aromatic
rings=0 mass % [0169] Nylon 66: Structural unit with formula
[--NH--(CH.sub.2).sub.6--NH--CO--(CH.sub.2).sub.4--CO--], molecular
weight of structural unit=226.32, proportion of aromatic rings=0
mass % [0170] MXD6: Structural unit with formula
[--NH--CH.sub.2-C.sub.6H.sub.4--CH.sub.2--NH--CO--(CH.sub.2).sub.4--CO--]-
, molecular weight of structural unit=246.34, proportion of
aromatic rings=30.9 mass % [0171] Nylon 9T: Structural unit with
formula [--NH--(CH.sub.2).sub.9--NH--CO--C.sub.6H.sub.4--CO--],
molecular weight of structural unit=288.43, proportion of aromatic
rings=26.4 mass %
[0172] And the proportions of aromatic rings in a copolymerized
polyamide and a mixed polyamide are determined as follows. [0173]
Case 1: Copolymerized polyamide or mixed polyamide of nylon 6 and
MXD6 (nylon 6/MXD6 ratio by mass=50/50)
[0174] Proportion of aromatic rings=(proportion of nylon
6.times.proportion of aromatic rings in nylon 6) +(proportion of
MXD6.times.proportion of aromatic rings in
MXD6)=(0.5.times.0)+(0.5.times.30.9)=15.5 (mass %) [0175] Case 2:
Copolymerized polyamide or mixed polyamide of nylon 66, MXD6 and
nylon 9T (nylon 66/MXD6/nylon 9T ratio by mass=50/25/25)
[0176] Proportion of aromatic rings=(proportion of nylon
66.times.proportion of aromatic rings in nylon 66)+(proportion of
MXD6.times.proportion of aromatic rings in MXD6)+(proportion of
nylon 9T.times.proportion of aromatic rings in nylon
9T)=(0.5.times.0)+(0.25.times.30.9)+(0.25.times.26.4)=14.35 (mass
%)
[0177] Physical properties of polyamide are explained below.
[0178] The molecular weight of polyamide is not particularly
limited so long as it allows easier hot-melt of the polyamide than
hot-melt of polyolefin present together in the resin composition.
For example, it is appropriate that the weight-average molecular
weight of polyamide be from 10,000 to 300,000, preferably from
10,000 to 100,000.
[0179] In addition, the glass transition temperature or melting
temperature (melting point) of polyamide is not particularly
limited as is the case with the molecular weight so long as it
allows easier hot-melt of the polyamide than hot-melt of polyolefin
present together in the resin composition. For example, it is
appropriate that the melting temperature (Tm) of each polyamide be
in a range of 100.degree. C. to 400.degree. C., preferably in a
range of 150.degree. C. to 350.degree. C.
[0180] By the way, the melting temperature (Tm) of polyamide is
determined by the same method as adopted in the foregoing melting
temperature measurement made on polyolefin. To be more specific,
the melting temperature (Tm) of polyamide is determined from the
DSC curve obtained by differential scanning calorimetry (DSC) as
"melting peak temperature" described in JIS K 7121-1987, directions
for determination of melting temperature in "methods for measuring
transition temperature of plastic".
-Carboxylic Anhydride-Modified Polyolefin Compatibilizer-
[0181] The compatibilizer is a resin allowing enhancement of an
affinity between polyolefin and polyamide.
[0182] The compatibilizer may be chosen in response to the
polyolefin used together.
[0183] As the compatibilizer, it is appropriate to use carboxylic
anhydride-modified polyolefin which has the same structure as the
polyolefin used together and contains, in portions of its molecule,
moieties having an affinity for polyamide.
[0184] The carboxylic anhydride-modified polyolefin is a modified
polyolefin having portions into which moieties containing
carboxylic anhydride residues are introduced.
[0185] For example, when the polyolefin is polypropylene (PP), the
modified polyolefin is preferably a modified polypropylene (PP),
while when the polyolefin is an ethylene-vinyl acetate copolymer
resin (EVA), the modified polyolefin is preferably a modified
ethylene-vinyl acetate copolymer resin (EVA).
[0186] As the modifying moiety which contains a carboxylic
anhydride residue and is introduced into a polyolefin, a maleic
anhydride residue in particular is suitable in point of further
enhancement of an affinity between polyolefin and polyamide, and
besides in point of the upper limit of temperature during the
molding process.
[0187] As a method for producing a modified polyolefin, there are
e.g. a method of directly forming chemical bonds by making the
foregoing compound having a modifying moiety react with a
polyolefin, and a method of forming graft chains by the use of the
foregoing compound having a modifying moiety, then making the graft
chains combine with a polyolefin.
[0188] Examples of the foregoing compound containing a modifying
moiety include maleic anhydride and citric anhydride and
derivatives of these anhydrides.
[0189] Of the above compatibilizers, a maleic anhydride-modified
polyolefin produced by making maleic anhydride as an unsaturated
carboxylic acid react with a polyolefin is preferred over the
others.
[0190] Examples of a modified polyolefin include maleic
anhydride-modified polypropylene, maleic anhydride-modified
polyethylene, maleic anhydride-modified ethylene-vinyl acetate
copolymer resin (EVA), and an acid-modified polyolefin such as an
addition product or copolymer of those recited above. When the
polyolefin is polypropylene, maleic anhydride-modified
polypropylene is especially preferred.
[0191] As the modified polyolefin, commercially available products
may be used.
[0192] Examples of a commercially available modified polypropylene
include UMEX.RTM. series (e.g. 100TS, 110TS, 1001, 1010) produced
by Sanyo Chemical Industries, Ltd.
[0193] Examples of a commercially available modified polyethylene
include UMEX.RTM. series (e.g. 2000) produced by Sanyo Chemical
Industries, Ltd., and a MODIC.RTM. series produced by Mitsubishi
Chemical Corporation.
[0194] Examples of a commercially available modified ethylene-vinyl
acetate copolymer resin (EVA) include a MODIC.RTM. series produced
by Mitsubishi Chemical Corporation.
[0195] By the way, the molecular weight of a compatibilizer has no
particular limits, but in melt-fabricable point of view, it is
preferably in a range of 5,000 to 100,000, more preferably in a
range of 5,000 to 80,000.
-Other Ingredients-
[0196] The resin composition relating to an embodiment of the
invention may further contain ingredients other than those
mentioned above.
[0197] Examples of other ingredients include well-known additives
such as a flame retardant, a flame retarding assistant, an agent
for inhibiting drips during heating (a drip inhibitor), a
plasticizer, an antioxidant, a release agent, a lightfastness
agent, a weatherproof agent, a coloring agent, pigments, a
modifier, an antistatic agent, a hydrolysis inhibitor, a filler and
a reinforcing agent other than carbon fibers (e.g. talc, clay,
mica, glass flakes, milled glass, glass beads, crystalline silica,
alumina, silicon nitride, aluminum nitride, boron nitride or so
on).
[0198] In addition to carbon fibers, other fibrous reinforcing
materials may be incorporated.
[0199] The other fibrous reinforcing materials have no particular
restrictions so long as they are fibrous in form. Examples of a
fibrous reinforcing material include continuous or discontinuous
reinforced fibers such as glass fiber, aramide fiber, silicon
carbide fiber, alumina fiber, boron fiber, tungsten carbide fiber
and organic fibers (e.g. aramide, vinylon, nylon and cellulose
fibers). Where fiber-reinforced fillers are concerned also, only
one kind thereof may be added, or two or more kinds thereof may be
added in combination.
[0200] The size of a fibrous reinforcing material has no particular
limits. It is appropriate for the fibrous reinforcing material to
have e.g. a number-average fiber length in a range of 20 .mu.m to
40 mm, preferably in a range of 30 .mu.m to 30 mm. In addition, it
is appropriate for the fibrous reinforcing material to have a
number-average fiber diameter in a range of 1 .mu.m to 30 .mu.m,
preferably in a range of 1 .mu.m to 20 .mu.m. By the way, it is
adequate that a reinforcing material in a raw material state before
undergoing melt-kneading with a thermoplastic resin or the like
meets requirements that its number-average fiber length and its
number-average fiber diameter be in the respective ranges specified
above, and it is preferred that the reinforcing material meet such
requirements even after undergoing melt-kneading.
[0201] It is appropriate for the foregoing other ingredients to be
added e.g. in an amount of 0 parts by mass to 10 parts by mass,
preferably in an amount of 0 parts by mass to 5 parts by mass, with
respect to 100 parts by mass of polyolefin. The expression "0 parts
by mass" herein means a state that no other ingredients are
incorporated.
<Resin Molding>
[0202] A resin molding relating to an embodiment of the invention
contains a polyolefin, a polyamide, carbon fibers and a
compatibilizer. In other words, the resin molding relating to an
embodiment of the invention is constituted of the same ingredients
that constitute the resin composition relating to an embodiment of
the invention.
[0203] More specifically, the present resin molding contains, with
respect to 100 parts by mass of a polyolefin, 1 part by mass to 50
parts by mass of a polyamide, 1 part by mass to 50 parts by mass of
carbon fibers having an average fiber length of 0.2 mm to 1 mm and
including carbon fibers having their fiber lengths in a range of 1
mm to 20 mm in a proportion of 1% to 20% by number to all the
carbon fibers, and 1 part by mass to 10 parts by mass of a
carboxylic anhydride-modified polyolefin as a compatibilizer.
[0204] In other words, the resin molding contains a polyolefin, and
further contains, per 100 parts by mass of polyolefin, a polyamide
in a content of 1 part by mass to 50 parts by mass, carbon fibers
in a content of 1 part by mass to 50 parts by mass and a
compatibilizer in a content of 1 part by mass to 10 parts by
mass.
[0205] And the carbon fibers have an average fiber length in a
range of 0.2 mm to 1 mm, and the percentage by number of the carbon
fibers from 1 mm to 20 mm in fiber length to all the carbon fibers
is from 1% to 20%.
[0206] In addition, the percentage by number of the carbon fibers
from 1 mm to 20 mm in fiber length to all the carbon fibers is
preferably from 5% to 20% from the viewpoint of enhancing impact
resistance.
[0207] By the way, it is appropriate for the resin molding relating
to an embodiment of the invention to be a non-crosslinked resin
molding.
[0208] The resin molding relating to an embodiment of the invention
may be one which is obtained by preparing a resin composition
relating to an embodiment of the invention, and then molding this
resin composition. In producing a resin molding relating to an
embodiment of the invention by molding a resin composition relating
to an embodiment of the invention, the carbon fibers included in
the resin molding are in a mixed state of first carbon fibers and
second carbon fibers.
[0209] Herein, the carbon fiber content represents the whole
quantity of carbon fibers included in the resin molding, and the
average fiber length of carbon fibers represents an average fiber
length of all the carbon fibers included in the resin molding. In
addition, the proportion by number of carbon fibers having their
fiber lengths in a range of 1 mm to 20 mm is expressed in terms of
the percentage by number to all the carbon fibers included in the
resin molding.
[0210] The method for measuring an average length of fibers
included in the molding is as described already. In addition, the
proportion by number of carbon fibers having their fiber lengths in
a range of 1 mm to 20 mm is determined by performing image analysis
according to the method described already and checking for the
number of carbon fibers having their fiber lengths in a range of 1
mm to 20 mm among all the carbon fibers on which average
fiber-length measurement have been made.
[0211] Examples of a method applicable to forming of a resin
molding relating to an embodiment of the invention include
injection molding, extrusion molding, blow molding, hot press
molding, calender molding, coating molding, cast molding, dipping
molding, vacuum molding and transfer molding.
[0212] The method for forming the resin molding relating to an
embodiment of the invention is preferably injection molding in
point of high degree of freedom in shaping.
[0213] The cylinder temperature in injection molding is e.g. from
180.degree. C. to 300.degree. C., preferably from 200.degree. C. to
280.degree. C. The mold temperature in injection molding is e.g.
from 30.degree. C. to 100.degree. C., preferably from 30.degree. C.
to 60.degree. C.
[0214] The injection molding may be carried out using a
commercially available machine, such as NEX150 made by NISSEI
PLASTIC INDUSTRIAL CO., LTD., NEX300 made by NISSEI PLASTIC
INDUSTRIAL CO., LTD., or SE5OD made by Sumitomo Heavy Industries,
Ltd.
[0215] The resin molding relating to an embodiment of the invention
are used suitably for application to electrical-electronic
instruments, office instruments, household electric appliances,
car's interior materials, containers or so on. More specifically,
they are used for cabinets of electrical-electronic instruments and
household electric appliances, various parts of
electrical-electronic instruments and household electric
appliances, car's interior parts, storage cases for CD-ROM, DVD and
the like, tableware, beverage bottles, food trays, wrapping
materials, film, tarpaulin and so on.
[0216] The resin molding relating to an embodiment of the invention
in particular is a resin molding superior in mechanical strengths,
notably in bending elasticity modulus, because carbon fibers are
adopted as reinforcing fibers, and hence it is used suitably as
substitutes for metallic parts.
Second Embodiment
(Resin Composition for Resin Molding)
[0217] The resin composition which relates to another embodiment of
the invention (hereafter referred simply to as "the resin
composition" in some cases) and is used for resin moldings includes
a first resin composition containing a first polyolefin, a
polyamide, carbon fibers having an average fiber length in a range
of 0.1 mm to 1 mm and a carboxylic anhydride-modified polyolefin as
a compatibilizer and a second resin composition containing a second
polyolefin and organic fibers having an average fiber length in a
range of 1 mm to 20 mm. Additionally, of the total quantity by mass
of the resin composition for resin moldings, taking the total for
the first polyolefin content and the second polyolefin content as
100 parts by mass, the polyamide content accounts for 1 part by
mass to 50 parts by mass, the carbon fiber content accounts for 1
part by mass to 50 parts by mass, the organic fiber content
accounts for 1 part by mass to 20 parts by mass and the
compatibilizer content account for 1 part by mass to 10 parts by
mass.
[0218] The first resin composition and the second polyolefin are
the same as those in the first embodiment, respectively.
[0219] The resin composition relating to this embodiment contains
carbon fibers having an average fiber length of 0.1 mm to 1 mm in
the first resin composition and organic fibers having an average
fiber length of 1 mm to 20 mm in the second resin composition.
Organic fibers resist breakage and cutting because of their high
elasticity as compared with carbon fibers. As a result, a resin
molding formed using this resin composition contains organic fibers
long in fiber length in addition to carbon fibers having shortened
fiber lengths. Specifically, the resin molding contains e.g. carbon
fibers having an average fiber length in a range of 0.1 mm to 1 mm
and organic fibers having an average fiber length in a range of 1
mm to 20 mm. And the resin molding is in a state that the
percentage of the number of fibers from 1 mm to 20 mm in fiber
length to the total for the number of carbon fibers and the number
of organic fibers is from 1% to 20%.
[0220] Under this state, even when impact force is applied on the
resin molding, the impact force is thought to be easy to diffuse
into the interior of the resin molding. It is therefore presumed
that the resin molding formed using the resin composition having
the foregoing constitution is improved in impact resisting
strength.
[0221] In point of improvement in impact resistance, it is
appropriate that the ratio (by mass) between the carbon fibers in
the first resin composition and the organic fibers in the second
resin composition fall within the range as specified below.
[0222] When the carbon fiber content and the organic fiber content,
referred to the whole quantity of the resin composition for a resin
molding, are symbolized by CF1 and OF2, respectively, it is
appropriate that the ratio by mass between CF1 and OF2 (CF1/0F2
ratio) be from at least CF1/0F2=60/40 to at most CF1/0F2=99/1
(preferably from at least 70/30 to at most 95/5). Additionally,
when the organic fiber content becomes higher, the bending
elasticity modulus is more likely to deteriorate.
(Manufacturing Method of Resin Composition)
[0223] The first resin composition is manufactured by the same
method as adopted in the first embodiment.
[0224] As an example of a method for manufacturing the second resin
composition, mention may be made of a method in which a second
polyolefin and long-length organic fibers cut down to an intended
length are subjected to melt kneading. As another example, mention
may be made of a method in which, while the organic fibers in
continuous fiber form (known as roving) are subjected to opening,
the surfaces thereof are impregnated and coated with a molten
polyolefin resin, and the thus processed carbon fibers are pulled
out (a pultrusion process). From the viewpoint of inhibiting
breakage of the organic fibers, it is preferred that the second
resin composition in particular be manufactured through the use of
such a pultrusion process.
(Constitution of Resin Composition)
[0225] In the next place, proportions of individual ingredient
contents in the whole quantity of the resin composition are
described.
[0226] The resin composition relating to this embodiment of the
invention has, as mentioned above, ingredient contents in their
respective proportions specified below in the whole quantity of the
resin composition including the first resin composition and the
second resin composition.
[0227] With respect to 100 parts by mass of total content of the
first polyolefin and the second polyolefin, the polyamide content
is from 1 part by mass to 50 parts by mass, the carbon fiber
content is from 1 part by mass to 50 parts by mass, the organic
fibers is from 1 part by mass to 20 parts by mass and the
compatibilizer content is from 1 part to 10 parts by mass.
[0228] The percentage of a polyolefin content (total for a first
polyolefin content and a second polyolefin content) to the whole
mass of resin composition may be determined in response to uses of
a resulting resin molding. For example, the polyolefin content
accounts for preferably 5 mass % to 95 mass %, more preferably 10
mass % to 95 mass %, still more preferably 20 mass % to 95 mass %,
of the total mass of resin composition.
[0229] The carbon fiber content is from 1 part by mass to 50 parts
by mass, preferably from 10 parts by mass to 50 parts by mass, more
preferably from 20 parts by mass to 40 parts by mass, referred to
100 parts by mass of polyolefin.
[0230] By containing carbon fibers in a proportion of at least 1
part by mass, referred to 100 parts by mass of polyolefin, the
resin composition aims reinforcement, and by adjusting the carbon
fiber content to 50 parts by mass or below, referred to 100 parts
by mass of polyolefin, good moldability is achieved at the time of
producing a resin molding.
[0231] The organic fiber content is from 1 part by mass to 20 parts
by mass, preferably from 2 parts by mass to 15 parts by mass, more
preferably from 5 parts by mass to 15 parts by mass, referred to
100 parts by mass of polyolefin.
[0232] By containing organic fibers in a proportion of at least 1
part by mass, referred to 100 parts by mass of polyolefin, the
resin composition aims reinforcement and can achieve improvement in
impact resistance, and by adjusting the organic fiber content to 20
parts by mass or below, referred to 100 parts by mass of
polyolefin, good moldability is achieved at the time of producing a
resin molding.
[0233] By the way, in the case of using a fibrous reinforcing agent
other than carbon fibers and organic fibers, it is appropriate that
the total for a carbon fiber content and an organic fiber content
account for at least 90% by mass of the total for the carbon fiber
content, the organic fiber content and the fibrous reinforcing
agent content.
[0234] The polyamide content is from 1 part by mass to 50 parts by
mass, refereed to 100 parts by mass of polyolefin. From the
viewpoint of further enhancing impact resistance, the polyamide
content is preferably from 2 parts by mass to 40 part by mass, more
preferably from 5 parts by mass to 30 parts by mass.
[0235] By adjusting the polyamide content to fall within the above
range, the affinity for the carbon fibers is increased, and
enhancement of impact resistance is aimed at.
-Organic Fibers-
[0236] The resin composition relating to this embodiment contains
organic fibers having an average fiber length of 1 mm to 20 mm in
the second resin composition. The average fiber length of organic
fibers is preferably from 2 mm to 18 mm, more preferably from 6 mm
to 15 mm.
[0237] The organic fibers included in the second resin composition
has no particular restrictions so long as their average fiber
length is in a range of 1 mm to 20 mm. In point of improvement in
impact resistance of resulting resin moldings, it is appropriate to
use organic fibers of the type which is produced by Roving method
and made up of great many fibers in a converged state.
[0238] The organic fibers has no particular restriction, but from
the viewpoint of incorporating them into the second resin
composition and resin moldings, it is appropriate for the organic
fibers to resist melting when they are heated for production of the
second resin composition and resin moldings. In this respect, it is
appropriate that the melting point, softening point or thermal
decomposition temperature of organic fibers be higher than the
melting point of polyolefin. For example, it is appropriate that
the melting point, softening point and thermal decomposition
temperature of organic fibers be at least 5.degree. C. higher than
the melting point of polyolefin. Such a temperature of organic
fibers has no particular upper limit, but the upper limit thereof
may be e.g. 200.degree. C. or lower.
[0239] Additionally, the melting point, softening point or thermal
decomposition temperature of organic fibers is measured as
follows.
[0240] The melting point of organic fibers can be determined by the
same method as used for melting-point measurement made on
polyolefin. Specifically, the melting point of organic fibers is
determined from the DSC curve obtained by differential scanning
calorimetry (DSC) as "melting peak temperature" described in JIS K
7121-1987, directions for determination of melting temperature in
"methods for measuring transition temperature of plastic".
[0241] The softening point of organic fibers is determined in
conformance with JIS K 7206-2016, "methods for determining Vicat
softening temperature (VST) of plastics-thermoplastic plastic".
[0242] The thermal decomposition temperature of organic fibers is
determined from a TG curve obtained by thermogravimetric
measurement (TG) conforming to JIS K 7121-1987, "methods for
thermogravimetric measurement of plastic", as the temperature at
which weight reduction of a sample begins.
[0243] Examples of organic fibers include fibers formed from resins
termed "engineering plastics".
[0244] To be more specific, examples of organic fibers include
ultrahigh molecular-weight polyethylene fibers; polycarbonate
fibers, polyarylate fibers, polyoxymethylene fibers; polyester
fibers, such as polybutylene terephthalate fibers, polybutylene
naphthalate fibers and liquid-crystalline aromatic polyethylene
terephthalate fibers; polybenzazole fibers, such as
polyparaphenylene benzobisoxazole (PBO) fibers and
polyparaphenylenebenzobisthiazole fibers; polyphenylene sulfide
fibers; modified polyphenylene ether fibers; polyamide fibers such
as nylon fibers; and aramide fibers such as poly-p-phenylene
terephthalamide fibers and poly-m-phenylene isophthalamide fibers.
Also, in addition to the above organic fibers, the organic fibers
such as vinylon fibers and cellulose fibers are exemplified.
[0245] These organic fibers may be used alone, or two or more kinds
thereof may be used in combination.
[0246] Of those organic fibers, at least one kind of organic fibers
selected from the group consisting of aramide fibers, vinylon
fibers and cellulose fiber are suitable, at least one kind selected
from aramide fibers or vinylon fibers is preferred, and aramide
fibers are much preferred.
[0247] Aramide is also described as all-aromatic polyamide, and
refers to fibrous polyamide constituted of structural units
containing aromatic rings in its molecular skeleton. The aramide
fibers are generally obtained using as a raw material an aramide
synthesized by copolymerization of diamine and dicarboxylic
acid.
[0248] As aramide fibers, publicaly known aramide fiber are used,
and more specifically, either of para-type aramide fibers (e.g.
poly-p-phenylene terephthalamide fibers) and meta-type aramide
fibers (e.g. poly-m-phenyleneisophthalamide fibers) can be
used.
[0249] The aramide fibers may be those having undergone
publicly-known surface treatment. Examples of surface treatment for
aramide fibers include oxidizing treatment and sizing
treatment.
[0250] The aramide fibers have no particular restrictions as to
their fiber diameter, and the fiber diameter may be chosen in
response to the uses of a resulting resin molding. The average
fiber diameter of aramide fibers may be e.g. from 5.0 .mu.m to 100
.mu.m (preferably from 10 .mu.m to 20 .mu.m).
[0251] The average fiber diameter of aramide fibers is determined
as follows. A cross section orthogonal to the length direction of
each individual aramide fiber is observed under an SEM (a scanning
electron microscope) set at a magnification of 1,000, and the
diameter of each individual aramide fiber is measured. This
measurement is made on 100 aramide fibers, and the average of
measured values is calculated and defined as the average diameter
of aramide fibers.
[0252] Vinylon fibers are e.g. fibers obtained using polyvinyl
alcohol as a raw material.
[0253] As the vinylon fibers, publicly-known vinylon fibers are
used. The vinylon fibers may be those having undergone surface
treatment.
[0254] As the cellulose fibers, publicly-known cellulose fibers are
used, with examples including fibers obtained using as a raw
material natural cellulose fibers such as cotton or jute.
[0255] Fiber diameters of vinylon fibers and cellulose fibers have
no particular limits, and they may be chosen in response to e.g.
uses of resulting resin moldings.
[0256] Now, there are provided explanation of a method for
measuring the fiber lengths of carbon fibers and organic fibers
included in a resin composition and the fiber lengths of carbon
fibers and organic fibers included in a resin molding as described
later.
[0257] To begin with, a subject for measurement, namely a resin
composition or a resin molding, is put in an aluminum crucible, and
fired at 500.degree. C. for 2 hours by means of a Muffle furnace.
After the firing, the carbon fibers remaining in the crucible are
collected, and dispersed into a 0.1% water solution of surfactant.
Photographs of the carbon fibers are taken using a digital
microscope (VHX-100, made by KEYENCE CORPORATION) under a
measurement magnification of 10. The fiber lengths of carbon fibers
are measured using image analysis software (WINROOF2015, produced
by MITANI CORPORATION). And this fiber-length measurement is made
on 200 carbon fibers, and the average value of fiber lengths thus
measured is defined as an average fiber length of carbon fibers. By
the way, the fiber length of carbon fibers is a number-average
fiber length.
[0258] By the way, there may be cases where, depending on organic
fibers included in the resin composition or the resin molding as a
subject for measurement, melting or disappearance of the organic
fibers occurs when the subject for measurement is fired at
500.degree. C. for 2 hours, and thereby average fiber-length
measurement becomes difficult. In such cases, average fiber-length
measurement on organic fibers can be made as follows.
[0259] A resin composition or a resin molding is dissolved in an
organic polar solvent such as N-methyl-2-pyrrolidone and heated
under reflux for 72 hours, and thereby the polyamide as a resinous
ingredient in the resin composition or the resin molding is brought
into at least either a dissolved or swollen state. Organic fibers
are removed from organic fiber-bearing residue, and organic fiber
lengths are measured according to the measurement method mentioned
above.
-Other Ingredients-
[0260] In addition to the ingredients mentioned above, the resin
composition relating to this embodiment may contain the same other
ingredients as included in the resin composition relating to the
first embodiment of the invention.
[0261] Further, in addition to the carbon fibers and the organic
fibers, other fibrous reinforcing materials may be
incorporated.
[0262] The other fibrous reinforcing materials have no particular
restrictions so long as they are fibrous in form. Examples of a
fibrous reinforcing material include continuous or discontinuous
reinforced fibers such as glass fiber, silicon carbide fiber,
alumina fiber, boron fiber and tungsten carbide fiber. As to
fibrous reinforcing materials also, one kind alone may be added, or
two or more kinds may be added in combination.
[0263] The size of a fibrous reinforcing material has no particular
limits. It is appropriate for the fibrous reinforcing material to
have e.g. a number-average fiber length in a range of 20 .mu.m to
40 mm, preferably in a range of 30 .mu.m to 30 mm. In addition, it
is appropriate for the fibrous reinforcing material to have a
number-average fiber diameter in a range of 1 .mu.m to 30 .mu.m,
preferably in a range of 1 .mu.m to 20 .mu.m. By the way, it is
adequate that a reinforcing material in a raw material state before
undergoing melt-kneading with a thermoplastic resin or the like
meets requirements that its number-average fiber length and its
number-average fiber diameter are in the respective ranges
specified above, and it is preferred that the reinforcing material
meet such requirements even after undergoing melt-kneading.
[0264] It is appropriate for the foregoing other ingredients to be
added e.g. in an amount of 0 parts by mass to 10 parts by mass,
preferably in an amount of 0 parts by mass to 5 parts by mass, with
respect to 100 parts by mass of polyolefin. The expression "0 parts
by mass" herein means a state that no other ingredients are
incorporated.
<Resin Molding>
[0265] A resin molding relating to this embodiment contains a
polyolefin, a polyamide, carbon fibers and a compatibilizer. In
other words, the resin molding relating to this embodiment is
constituted of the same ingredients that constitute the resin
composition relating to this embodiment.
[0266] More specifically, the present resin molding contains, with
respect to 100 parts by mass of a polyolefin, 1 part by mass to 50
parts by mass of a polyamide, 1 part by mass to 50 parts by mass of
carbon fibers having an average fiber length of 0.1 mm to 1 mm, 1
part by mass to 20 parts by mass of organic fibers having an
average fiber length of 1 mm to 20 mm, and 1 part by mass to 10
parts by mass of a carboxylic anhydride-modified polyolefin as a
compatibilizer, wherein the percentage by number of fibers from 1
mm to 20 mm in fiber length to the total for the carbon fibers and
the organic fibers is from 1% to 20%.
[0267] In other words, the resin molding contains a polyolefin, and
further contains, per 100 parts by mass of the polyolefin, a
polyamide in a content of 1 part by mass to 50 parts by mass,
carbon fibers in a content of 1 part by mass to 50 parts by mass,
organic fibers in a content of 1 part by mass to 20 parts by mass,
and a compatibilizer in a content 1 part by mass to 10 parts by
mass.
[0268] Additionally, the carbon fibers included in the resin
molding have an average fiber length in a range of 0.1 mm to 1 mm,
and the organic fibers included in the resin molding have an
average fiber length in a range of 1 mm to 20 mm.
[0269] As to carbon fibers and organic fibers included in the resin
molding, the percentage by number of fibers from 1 mm to 20 mm in
fiber length to the total for the carbon fiber and the organic
fibers is from 1% to 20%.
[0270] And, from the viewpoint of enhancing impact resistance, it
is preferred that the total for carbon fibers and organic fibers
having their fiber lengths in a range of 1 mm to 20 mm account for
5% to 20% by number of all the carbon fibers and the organic fibers
included in the resin molding.
[0271] Herein, the proportion of the number of carbon fibers having
fiber lengths of 1 mm or above to the total for the number of
carbon fibers and the number of organic fibers is preferably
0%.
[0272] By the way, it is appropriate for the resin molding relating
to this embodiment to be a non-crosslinked resin molding.
[0273] The resin molding relating to this embodiment may be one
which is obtained by preparing a resin composition relating to this
embodiment, and then molding this resin composition. When a resin
molding relating to this embodiment is molded using a resin
composition relating to this embodiment, carbon fibers having
shortened fiber lengths and organic fibers having long fiber
lengths are in a mixed state in the resin molding.
[0274] The method for measuring an average fiber length of fibers
included in the molding is as described already. In addition, the
proportion by number of the total for carbon fibers and organic
fibers having their fiber lengths in a range of 1 mm to 20 mm is
determined by performing image analysis according to the method
described already and checking for the number of carbon fibers and
organic fibers having their fiber lengths in a range of 1 mm to 20
mm among all the carbon fibers and the organic fibers on which
average fiber-length measurement have been made.
[0275] The molding method and uses of the resin molding are the
same as in the case of resin moldings relating to the first
embodiment.
Examples
[0276] The invention will now be illustrated in more detail by
reference to the following examples, but these examples should not
be construed as limiting the invention in any way.
Examples 1 to 11 and Comparative Examples 1 to 11
(Preparation for Resin Composition)
[0277] Each of pellets A-1 to A-8 as the first resin compositions
was prepared by kneading a set of ingredients as shown in Table 1
under kneading conditions described below and a melt-kneading
temperature (cylinder temperature) as indicated in Table 1 by means
of a twin-screw kneader (TEM58SS, made by TOSHIBA MACHINE CO.,
LTD.) incorporating a low-shear screw having a compression ratio of
1.8 and one pin-type mixing section in its screw structure.
[0278] By the way, the carbon fibers used for preparation of the
pellets A-1 to A-8 were as follows.
[0279] (TORAYCA.RTM., produced by Toray Industries, Inc., chopped
carbon fibers having undergone surface treatment, average fiber
length: 20 mm, average fiber diameter: 7 .mu.m)
-Kneading Conditions-
[0280] Screw diameter: .phi.58 mm, number of revolutions: 80 rpm,
discharge nozzle diameter: 1 mm
[0281] A pellet B-1 was prepared as a second resin composition
containing 20 mm-length carbon fibers through the use of PLASTRON
PP-CF40 (produced by Daicel Polymer, Ltd.).
[0282] A pellet B-2 was prepared as a second resin composition
containing 6 mm-length carbon fibers through the use of PLASTRON
PP-CF40 (produced by Daicel Polymer, Ltd.).
[0283] A pellet B-3 was prepared as a second resin composition
containing 25 mm-length carbon fibers through the use of PLASTRON
PP-CF40 (produced by Daicel Polymer, Ltd.).
[0284] A pellet B-4 was prepared as a second resin composition
containing 5 mm-length carbon fibers through the use of PLASTRON
PP-CF40 (produced by Daicel Polymer, Ltd.).
[0285] Further, average fiber-length measurement of carbon fibers
was made on each of the pellets A-1 to A-8 and the pellets B-1 to
B-4 in accordance with the method described already. Results of the
measurements are shown in Table 1.
TABLE-US-00001 TABLE 1 Manufacturing Example No. 1 2 3 4 5 6 7 8 --
-- -- -- Pellet No. A-1 A-2 A-3 A-4 A-5 A-6 A-7 A-8 B-1 B-2 B-3 B-4
Ingredient PP 60 55 55 55 55 55 60 60 60 60 content PE 55 (parts by
EVA 55 mass) PA6 15 30 15 30 10 10 PA66 30 MXD6 30 15 MA-PP 5 5 5 5
5 10 MA-PE 5 MA-EVA 5 Carbon fibers 20 10 10 10 10 5 30 30 40 40 40
40 Total 100 100 100 100 100 100 100 100 100 100 100 100
Melt-kneading temperature (.degree. C.) 240 240 270 240 240 240 240
240 -- -- -- -- Average fiber-length of carbon fibers (mm) 0.4 0.4
0.4 0.4 0.4 0.4 0.5 0.5 20 6 25 5 Note Polyamide content (per 100
parts 25 55 55 55 55 55 18 18 0 0 0 0 of PO) Compatibilizer content
(per 100 8 9 9 9 9 18 9 9 0 0 0 0 parts of PO) Carbon fiber content
(per 100 parts 33 18 18 18 18 9 55 55 67 67 67 67 of PO)
(Injection Molding)
[0286] Each of the pellets A-1 to A-8 and each of the pellets B-1
to B-4 were mixed together according to the formula as shown in
Table 2 or Table 3, and molded into an ISO multipurpose dumbbell
test piece (compliant with ISO 527 tensile test and ISO 178 bending
test) (test part thickness 4 mm, width 10 mm) and a D2 test piece
(length 60 mm, width 60 mm, thickness 2 mm) by using an injection
molding machine (NEX150, made by NISSEI PLASTIC INDUSTRIAL CO.,
LTD.) at a cylinder temperature as indicated in Table 2 or Table 3
and a mold temperature 50.degree. C. under a back pressure of 10
MPa.
<Evaluations>
[0287] By using the two kinds of test pieces thus formed, the
following evaluations were made. Evaluation results obtained are
shown in Table 2 and Table 3.
(Analysis of Carbon Fibers)
[0288] The average fiber length of carbon fibers and the percentage
by number of carbon fibers from 1 mm to 20 mm in fiber length to
all the carbon fibers (hereafter expressed as "percentage of carbon
fibers at least 1 mm in length") were measured according to the
already-described methods, respectively. (Flowability of Resin
Composition for Molding)
[0289] Flowability of a mixed pellet obtained by mixing each of the
pellets A-1 to A-8 with each of the pellets B-1 to B-4 was
evaluated in the following manner. Evaluation results are shown in
Table 2 and Table 3.
[0290] Injection molding was carried out using a mold provided with
a resin injection port in the central part and a groove spiraling
from the injection port as its starting point, and the length of an
injected resin was measured.
[0291] Spiral shape: 5 mm width, 3 mm thickness, 750 mm maximum
flow length
[0292] Injection pressure: 100 MPa
[0293] Injection speed: 50 mm/s
-Evaluation Criteria-
[0294] A: Spiral flow length is 300 mm or longer
[0295] B: Spiral flow length is 200 mm to shorter than 300 mm
[0296] C: Spiral flow length is shorter than 200 mm
(Moldability in Forming Resin Molding)
[0297] Moldability of each resin composition was evaluated as
follows.
[0298] After forming a resin pellet from each of the compositions
prepared so as to have ingredient contents according to Table 2 or
Table 3, a 4 mm-thick multipurpose test piece A1 conforming to JIS
K7139 was molded into a dumbbell sample by means of an injection
molding machine.
-Evaluation Criteria-
[0299] A: Molding defects including unevenness, defective part and
the like are not observed in all area of the molded surface, namely
the molded surface is uniform.
[0300] B: Molding defects including unevenness, defective part and
the like are developed in an area smaller than 20% of the molded
surface.
[0301] C: Molding defects including unevenness, defective part and
the like are developed in an area larger than or equal to 20% of
the molded surface.
(Bending Elasticity Modulus)
[0302] Bending elasticity modulus measurements were made on each of
the foregoing ISO multipurpose dumbbell test pieces by using a
method conforming to ISO178 and universal testing apparatus
(Autograph AG-Xplus, made by SHIMADZU CORPORATION).
(Impact Resistance)
[0303] Each of the foregoing ISO multipurpose dumbbell test pieces
was subjected to notching (4 mm in plate thickness), and its Charpy
impact strength (kJ/m.sup.2) was measured by conforming to the
method defined in ISO 179 and using an impact testing instrument
(DG-5, made by Toyo Seiki Seisaku-Sho, Ltd.). The greater the
measured value, the higher the impact resisting strength.
(Presence or Absence of Covering Layer)
[0304] Each of the foregoing D2 test pieces was checked up on the
presence or absence of a covering layer of polyamide in accordance
with the method described already.
TABLE-US-00002 TABLE 2 Example No. 1 2 3 4 5 6 7 8 9 10 11 Mixed
pellet Ingredient A-1 95 85 55 95 content A-2 80 (parts by A-3 80
mass) A-4 80 A-5 80 A-6 50 A-7 90 A-8 90 B-1 5 15 45 20 20 20 20 50
10 10 B-2 5 B-3 B-4 Total 100 100 100 100 100 100 100 100 100 100
100 First carbon fiber CF1 19 17 11 8 8 8 8 2.5 19 27 27 (parts by
mass) Second carbon fiber CF2 2 6 18 8 8 8 8 20 2 4 4 (parts by
mass) Carbon fiber ratio 90/10 74/36 38/62 50/50 50/50 50/50 50/50
11/89 90/10 87/23 87/23 (CF1/CF2) Resin Ingredient PP 60 60 60 56
56 56 56 57.5 60 6 6 Molding content PE 49.5 (parts by EVA 49.5
mass) PA6 14.25 12.75 8.25 24 12 15 14.25 9 9 PA66 24 MXD6 24 12
MA-PP 4.75 4.25 2.75 4 4 4 4 5 4.75 MA-PE 4.5 MA-EVA 4.5 Carbon
fiber 21 23 29 18 16 16 16 22.5 21 31 31 Total 100 100 100 100 100
100 100 100 100 100 100 Molding temp. (Cylinder 250 250 250 250 280
250 250 250 250 250 250 temp. .degree. C.) Carbon fiber Average 0.2
0.2 0.5 0.4 0.8 0.4 0.4 0.9 0.2 0.2 0.2 fiber length Percentage 2
10 10 15 18 15 15 19 1 1 1 of carbon fibers at least 1 mm in length
(number %) Property Flowability A A A A A A A B A A A of resin
composition Moldability A A A A A A A A A A A in forming resin
molding Bending 16 16 20 14 14 14 14 15 12 10 15 elasticity modulus
(Gpa) Charpy 10 11 10 13 12 12 12 16 15 16 11 (kJ/m.sup.2) Presence
or Pres- Presence Pres- Presence Pres- Presence Pres- Pres-
Presence Pres- Presence absence of ence ence ence ence ence ence
covering Note Polyamide content (parts 23.8 21.5 13.8 42.9 42.9
42.9 42.9 26.1 23.8 16.2 16.2 per 100 parts of PO) Compatibilizer
content 7.9 7.1 4.6 7.1 7.1 7.1 7.1 8.7 7.9 8.1 8.1 (parts per 100
parts of PO) Carbon fiber content 35 38.3 48.3 28.6 28.6 28.6 28.6
39.1 35 55.9 55.9 (parts per 100 parts of PO)
TABLE-US-00003 TABLE 3 Comparative Example No. 1 2 3 4 5 6 7 8 9 10
11 Mixed pellet Ingredient A-1 100 20 80 content A-2 100 (parts by
A-3 98 mass) A-4 5 A-5 A-6 95 80 A-7 100 A-8 100 B-1 100 2 95 5 20
B-2 B-3 80 B-4 20 Total 100 100 100 100 100 100 100 100 100 100 100
First carbon fiber CF1 20 10 0 9.8 0.5 4.75 4 30 30 4 16 (parts by
mass) Second carbon fiber CF2 0 0 40 0.8 35 2 8 0 0 32 8 (parts by
mass) Carbon fiber ratio 100/0 100/0 0/100 92/8 1/99 70/30 33/67
100/0 100/0 11/89 67/33 (CF1/CF2) Resin Ingredient PP 60 55 60 55.1
59.75 55.25 56 60 60 Molding content PE 55 (parts by EVA 55 mass)
PA6 15 30 28.5 24 10 10 3 12 PA66 29.4 MXD6 1.5 MA-PP 5 5 4.9 0.25
9.5 1 1 4 MA-PE 5 MA-EVA 5 Carbon fiber 20 10 40 10.6 36.5 6.75 12
30 30 36 24 Total 100 100 100 100 100 100 100 100 100 100 100
Molding temperature. 250 250 250 280 250 250 250 250 250 250 250
(Cylinder temperature .degree. C.) Carbon fiber Average 0.2 0.2 2
0.2 1.5 0.3 0.3 0.5 0.5 5 0.18 fiber length Percentage 0 0 30 0.8
22 4 4 0 0 25 0.5 of carbon fibers at least 1 mm in length (number
%) Property Flowability A A C A C A A A A B A of resin composition
Moldability C C B A C B B B B B B in forming resin molding Bending
8 6 18 6 19 5 7 9 8 7 10 elasticity modulus (Gpa) Charpy 4 4 6 4 4
4 4 7 8 12 6 (kJ/m.sup.2) Presence or Presence Pres- Presence Pres-
Presence Presence Pres- Presence Pres- Pres- Pres- absence of ence
ence ence ence ence ence covering Note Polyamide content (per 25
54.3 0 53.4 2.5 51.6 42.9 18.2 18.2 5 26 100 parts of PO)
Compatibilizer content 8.3 9.1 0 8.9 0.4 17.2 14.3 9.1 9.1 1.7 6.7
(per 100 parts of PO) Carbon fiber content (per 33.3 18.2 66.7 19.2
64.4 12.2 21.4 54.5 54.5 60 40 100 parts of PO)
[0305] The wording "content (per 100 parts of PO)" in the note
column refers to a content expressed in parts by mass with respect
to 100 parts by mass of polyolefin.
[0306] Details of the kinds of ingredients in Table 1 to Table 3
are as follows.
-Polyolefin-
[0307] PP: Polypropylene (NOVATEC.RTM. PPMA3, produced by Japan
Polypropylene Corporation)
[0308] PE: Polyethylene (ULTZEX.RTM. 20100J, produced by Prime
Polymer Co., Ltd.)
[0309] EVA: Ethylene-vinyl acetate copolymer resin (41XEV250,
produced by DU PONT-MITSUI POLYCHEMICALS CO., LTD.)
-Polyamide: Aliphatic PA (Aliphatic Polyamide)-
[0310] PA6: (Nylon 6 Zytel.RTM. 7331J, produced by Du Pont, melting
temperature: 225.degree. C.)
[0311] PA66: (Nylon 66 101L, produced by Du Pont, melting
temperature: 260.degree. C.)
-Polyamide: Aromatic PA (Aromatic Polyamide)-
[0312] MXD6: (MXD6 produced by MITSUBISHI GAS CHEMICAL COMPANY,
INC., melting temperature: 237.degree. C.)
-Compatibilizer-
[0313] MA-PP: Maleic anhydride-modified polypropylene (UMEX.RTM.
110TS, produced by Sanyo Chemical Industries, Ltd.)
[0314] MA-PE: Maleic anhydride-modified polyethylene (MODIC.RTM.
M142, produced by Mitsubishi Chemical Corporation)
[0315] MA-EVA: Maleic anhydride-modified ethylene-vinyl acetate
copolymer resin (MODIC.RTM. A543, produced by Mitsubishi Chemical
Corporation)
[0316] As can be seen from the data shown above, results of impact
resisting strength evaluations made on Examples are better than
those made on Comparative Examples.
[0317] In addition, by analyzing each of the moldings produced in
Examples in accordance with the method described already, it has
been ascertained that there was a layer of the compatibilizer used
(a layer of maleic anhydride-modified polypropylene, maleic
anhydride-modified polyethylene or maleic anhydride-modified
ethylene-vinyl acetate copolymer resin (EVA)) between the covering
layer and the polyolefin (or equivalently, a layer of
compatibilizer was formed on the covering layer's surface).
* * * * *