U.S. patent application number 11/919206 was filed with the patent office on 2009-10-29 for biodegradable resin composition and molded body and production method thereof.
Invention is credited to Mitsuhiro Kawahara, Takahiro Kusumoto, Miho Nakai, Shun Takahashi, Mikiya Tanaka, Kazue Ueda.
Application Number | 20090270530 11/919206 |
Document ID | / |
Family ID | 37307896 |
Filed Date | 2009-10-29 |
United States Patent
Application |
20090270530 |
Kind Code |
A1 |
Nakai; Miho ; et
al. |
October 29, 2009 |
Biodegradable resin composition and molded body and production
method thereof
Abstract
There is disclosed a biodegradable resin composition containing
100 parts by mass of a biodegradable polyester resin containing not
less than 50% by mass of polylactic acid, 0.1 to 10 parts by mass
of a layered silicate, 0.1 to 5 parts by mass of a carbodiimide
compound and 0.01 to 5 parts by mass of a phosphite organic
compound. Alternatively, the biodegradable resin composition
contains a phosphite organic compound and at least one additive
selected from the group consisting of a hindered phenol compound, a
benzotriazole compound, a triazine compound and a hindered amine
compound in an amount of 0.01 to 5 parts by mass in total, instead
of containing 0.01 to 5 parts by mass of the phosphite organic
compound.
Inventors: |
Nakai; Miho; (Kyoto, JP)
; Kawahara; Mitsuhiro; (Kyoto, JP) ; Ueda;
Kazue; (kyoto, JP) ; Takahashi; Shun;
(Kanagawa, JP) ; Kusumoto; Takahiro; (Kanagawa,
JP) ; Tanaka; Mikiya; (Kanagawa, JP) |
Correspondence
Address: |
Fildes & Outland
20916 Mack Ave Ste 2
Grosse Pointe Woods
MI
48236
US
|
Family ID: |
37307896 |
Appl. No.: |
11/919206 |
Filed: |
April 25, 2006 |
PCT Filed: |
April 25, 2006 |
PCT NO: |
PCT/JP2006/308615 |
371 Date: |
October 23, 2007 |
Current U.S.
Class: |
523/124 |
Current CPC
Class: |
C08K 5/29 20130101; C08K
2201/018 20130101; C08K 5/524 20130101; C08K 5/29 20130101; C08L
67/04 20130101; C08K 5/524 20130101; C08L 67/04 20130101 |
Class at
Publication: |
523/124 |
International
Class: |
D06P 1/52 20060101
D06P001/52 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 26, 2005 |
JP |
2005 128054 |
Claims
1. A biodegradable resin composition comprising: 100 parts by mass
of a biodegradable polyester resin comprising not less than 50% by
mass of polylactic acid; 0.1 to 5 parts by mass of a carbodiimide
compound; 0.1 to 10 parts by mass of a layered silicate; and 0.01
to 5 parts by mass of a phosphite organic compound.
2. The biodegradable resin composition according to claim 1,
wherein the biodegradable resin composition has a
strength-retaining rate of not less than 60% when being held at
60.degree. C. and at a relative humidity of 95 % for 300 hours.
3. The biodegradable resin composition according to claim 1,
wherein the biodegradable resin composition has a YI value of not
more than 25 as measured by a colorimeter.
4. The biodegradable resin composition according to claim 1,
wherein the layered silicate comprises primary, secondary, tertiary
or quaternary ammonium ions, pyridinium ions, imidazolium ions or
phosphonium ions ionically bonded between layers thereof.
5. A biodegradable resin composition comprising: 100 parts by mass
of a biodegradable polyester resin comprising not less than 50% by
mass of polylactic acid; 0.1 to 5 parts by mass of a carbodiimide
compound; 0.1 to 10 parts by mass of a layered silicate; a
phosphite organic compound; and at least one additive selected from
the group consisting of a hindered phenol compound, a benzotriazole
compound, a triazine compound and a hindered amine compound,
wherein the biodegradable resin composition comprises the phosphite
organic compound and the additive in an amount of 0.01 to 5 parts
by mass in total.
6. The biodegradable resin composition according to claim 5,
wherein the biodegradable resin composition has a
strength-retaining rate of not less than 60% when being held at
60.degree. C. and at a relative humidity of 95 % for 300 hours.
7. The biodegradable resin composition according to claim 5,
wherein the biodegradable resin composition has a YI value of not
more than 25 as measured by a colorimeter.
8. The biodegradable resin composition according to claim 5,
wherein the layered silicate contains primary, secondary, tertiary
or quaternary ammonium ions, pyridinium ions, imidazolium ions or
phosphonium ions ionically bonded between layers thereof.
9. A molded body comprising the biodegradable resin composition
according to claim 1.
10. A method for producing a biodegradable resin composition
comprising: adding a layered silicate when melt-mixing the
biodegradable resin composition or when polymerizing the
biodegradable polyester resin, in producing the biodegradable resin
composition according to claim 1.
11. A method for producing a biodegradable resin composition
comprising: adding a carbodiimide compound and a phosphite compound
when melt-mixing the biodegradable resin composition or when
polymerizing the biodegradable polyester resin, in producing the
biodegradable resin composition according to claim 1.
12. A molded body comprising the biodegradable resin composition
according to claim 5.
13. A method for producing a biodegradable resin composition
comprising: adding a layered silicate when melt-mixing the
biodegradable resin composition or when polymerizing the
biodegradable polyester resin, in producing the biodegradable resin
composition according to claim 5.
14. A method for producing a biodegradable resin composition
comprising: adding a carbodiimide compound and a phosphite compound
when melt-mixing the biodegradable resin composition or when
polymerizing the biodegradable polyester resin, in producing the
biodegradable resin composition according to claim 5.
Description
TECHNICAL FIELD
[0001] The present invention relates to a biodegradable resin
composition having excellent color tone, strength and gas barrier
property and having improved durability under a moisture heat
condition, a molded body made of the composition, and a production
method of the composition.
BACKGROUND ART
[0002] In recent years, biodegradable resins typified by polylactic
acid have attracted attention from the viewpoint of environmental
conservation. Of the biodegradable resins, the polylactic acid is
highly useful, because the polylactic acid has excellent
transparency, is one of the most heat-resistant resins, is less
costly due to the mass-producibility from vegetable-derived
materials such as corn and sweet potato, and can contribute also to
reduction of oil materials. However, when a molded body is produced
by only the biodegradable resin, the molded body has insufficient
long term storage stability and moisture heat resistance to cause
problems such as the reduction of the strength and molecular weight
caused by deterioration and the deteriorated appearance caused by
the reduction of the molecular weight. Therefore, the molded body
cannot endure applications where the molded body is repeatedly-used
and prolonged use.
[0003] As a technique for solving this problem, JP-A-2001-261797
discloses that hydrolysis resistance is enhanced by blocking a
carboxyl end of polylactic acid with a specific carbodiimide
compound. As a method for enhancing the other performance of a
biodegradable resin, JP-A-2001-49097 discloses that heat stability
can be applied by adding a phenol phosphite compound to an
aliphatic polyester resin.
[0004] As a method for enhancing the other performance of a
biodegradable resin, JP-A-2002-338796 discloses that the strength
and gas barrier property or the like of the biodegradable resin are
enhanced by adding a layered silicate organically treated by
specific ammonium ions to the biodegradable resin. JP-A-9-48908
discloses that hindered phenol, organic phosphite and a phosphonite
compound are added to a thermoplastic polyester resin as a method
for suppressing coloration when adding a layered silicate to the
thermoplastic polyester resin. JP-A-2000-212422 discloses that the
appearance and rigidity of a thermoplastic polyester resin made of
diol and dicarboxylic acid can be enhanced by adding a layered
silicate, one of benzophenone, benzotriazole and cyanoacrylate, and
a phosphite compound to the thermoplastic polyester resin.
DISCLOSURE OF THE INVENTION
Problem to be Solved by the Invention
[0005] However, when the layered silicate is used for the
polylactic acid resin, low-molecular weight substances and metal
salts of lactic acid are deposited on the surface of the molded
body during the long term storage of the molded body obtained using
the resin to cause problems such as deteriorated appearance and
reduced color tone caused by coloration by an ionic compound
contained in the layered silicate. Unfortunately, the strength is
reduced by the long term storage.
[0006] Even if the carbodiimide compound of JP-A-2001-261797 is
added for preventing the strength reduction during the long term
storage of the polylactic acid resin containing the layered
silicate, the coloration of the polylactic acid resin is
insufficiently suppressed in the presence of the layered silicate,
and the effect for improving the strength reduction is also
insufficient. Also, the generation of the deposited substance on
the surface of the molded body during the prolonged storage cannot
be suppressed.
[0007] Even if the phenol phosphite, the hindered phenol compound
or the phosphonite compound and the like is applied to the
polylactic acid as described in JP-A-2001-49097 and JP-A-9-48908,
the problems such as the strength reduction and the deposited
substances during the long term storage are not solved although the
effect for improving the color tone is observed in some
compounds.
[0008] Even if benzophenone, benzotriazole or cyanoacrylate, and
the phosphite compound are added in the system containing the
layered silicate as described in JP-A-2000-212422, the appearance
is insufficiently improved, and the moisture heat resistance is
unsuitable for practical use. In addition, JP-A-2000-212422 does
not refer the polylactic acid which is a biodegradability
polyester.
[0009] To solve the aforesaid problems, it is an object of the
present invention to provide a biodegradable resin composition
having excellent color tone, strength and gas barrier property and
suppressing the strength reduction and the generation of deposited
substances under a moisture heat condition.
Means for Solving Problem
[0010] As the results of the intensive studies for solving the
problems, the present inventors have found that the initial color
tone is improved by adding a carbodiimide compound and phosphite
organic compound of a specified amount with a layered silicate to a
biodegradable polyester resin consisting mainly of polylactic acid,
and the strength reduction and the generation of deposited
substances in high temperature and high humidity are suppressed,
and attained the present invention.
[0011] The characteristic of the present invention is as
follows.
[0012] (1) A biodegradable resin composition comprises:
[0013] 100 parts by mass of a biodegradable polyester resin
containing not less than 50% by mass of polylactic acid;
[0014] 0.1 to 5 parts by mass of a carbodiimide compound;
[0015] 0.1 to 10 parts by mass of a layered silicate; and
[0016] 0.01 to 5 parts by mass of a phosphite organic compound.
[0017] (2) The biodegradable resin composition according to the
item (1) comprises the phosphite organic compound and at least one
additive selected from the group consisting of a hindered phenol
compound, a benzotriazole compound, a triazine compound and a
hindered amine compound in an amount of 0.01 to 5 parts by mass in
total, instead of containing 0.01 to 5 parts by mass of the
phosphite organic compound.
[0018] (3) The biodegradable resin composition according to the
item (1) or (2), wherein the biodegradable resin composition has a
strength-retaining rate of not less than 60% when being held at
60.degree. C. and at a relative humidity of 95% for 300 hours.
[0019] (4) The biodegradable resin composition according to any of
the items (1) to (3), wherein the biodegradable resin composition
has a YI value of not more than 25 when the resin composition is
measured by a colorimeter.
[0020] (5) The biodegradable resin composition according to any of
the items (1) to (4), wherein the layered silicate contains
primary, secondary, tertiary or quaternary ammonium ions,
pyridinium ions, imidazolium ions or phosphonium ions ionically
bonded between layers thereof.
[0021] (6) A molded body comprises the biodegradable resin
composition according to any of the items (1) to (5).
[0022] (7) A method for producing a biodegradable resin composition
comprises:
[0023] adding a layered silicate when melt-mixing the biodegradable
resin composition or when polymerizing a biodegradable polyester
resin, in producing the biodegradable resin composition according
to any of the items (1) to (5).
[0024] (8) A method for producing a biodegradable resin composition
comprises:
[0025] adding a carbodiimide compound and a phosphite compound when
melt-mixing the biodegradable resin composition or when
polymerizing a biodegradable polyester resin, in producing the
biodegradable resin composition according to any of the items (1)
to (5).
EFFECT OF THE INVENTION
[0026] The present invention can provide a biodegradable resin
composition having excellent color tone, strength and gas barrier
property, maintaining strength and molecular weight for a long
period of time even in high temperature and high humidity, and
suppressing the generation of deposited substances such as
low-molecular weight substances and metal salts of polylactic acid.
This resin composition can be used for various types of molded
bodies, and can be well used for various applications. The resin
composition of the present invention, which has biodegradability,
can be composted when being discarded. Therefore, the resin
composition can be reused as a fertilizer, and the amount of
garbage can be reduced. The polylactic acid, which is generally
produced from raw materials derived from corn and sweet potato or
the like, can contribute to the prevention of depletion of
petroleum resources.
BEST MODE FOR CARRYING OUT THE INVENTION
[0027] Hereinafter, the present invention will be described in
detail.
[0028] A biodegradable polyester resin of a biodegradable resin
composition of the present invention should contain not less than
50% by mass of polylactic acid. The proportion of the polylactic
acid is preferably not less than 60% by mass, more preferably not
less than 80% by mass. If the proportion of the biodegradable resin
other than the polylactic acid is more than 50% by mass, the
resulting biodegradable resin composition is inferior in mechanical
strength, transparency and heat resistance. Raw materials derived
from vegetable are preferably used for the polylactic acid since
petroleum resources are reducibly used.
[0029] Examples of the polylactic acids employed as a major
component of the biodegradable polyester resin include
poly(L-,lactic acid), poly(D-lactic acid), or a mixture or
copolymer of poly(L-lactic acid) and poly(D-lactic acid). The
polylactic acid is produced by employing a known melt
polymerization method optionally along with a solid-phase
polymerization method if needed.
[0030] Examples of the biodegradable resins which can be used for
the present invention and are other than the polylactic acid
include aliphatic polyesters such as poly(ethylene succinate),
poly(butylene succinate) and poly(butylene succinate-co-butylene
adipate) which are each prepared from a diol and a dicarboxylic
acid; polyhydroxycarboxylic acids such as polyglycolic acid,
poly(3-hydroxybutyric acid), poly(3-hydroxyvaleric acid) and
poly(3-hydroxycaproic acid); poly(.omega.-hydroxyalkanoate) such as
poly(.epsilon.-caprolactone) and poly(.delta.-valerolactone); and
poly(butylene succinate-co-butylene terephthalate) and
poly(butylene adipate-co-butylene terephthalate) which each contain
an aromatic component but yet have biodegradability. Other examples
include polyester amides, polyester carbonates, and polysaccharides
such as starch. These components may be used either alone or in
combination, and may be copolymerized. The components may be merely
mixed to the polylactic acid which is the major component, and may
be copolymerized.
[0031] In the present invention, the biodegradable resin
composition contains a carbodiimide compound for applying long-term
moisture heat resistance and appearance stability to the
biodegradable resin composition.
[0032] Specific examples of the carbodiimide compounds used in the
present invention include [0033]
N,N'-di-2,6-diisopropylphenylcarbodiimide, [0034]
N,N'-di-o-tolylcarbodiimide, [0035] N,N'-diphenylcarbodiimide,
[0036] N,N'-dioctyldesylcarbodiimide, [0037]
N,N'-di-2,6-dimethylphenylcarbodiimide, [0038]
N-tolyl-N'-cyclohexylcarbodiimide, [0039]
N,N'-di-2,6-di-tert-butylphenylcarbodiimide, [0040]
N-triyl-N'-phenylcarbodiimide, [0041]
N,N'-di-p-nitrophenylcarbodiimide, [0042]
N,N'-di-p-aminophenylcarbodiimide, [0043]
N,N'-di-p-hydroxyphenylcarbodiimide, [0044]
N,N'-di-cyclohexylcarbodiimide, [0045] N,N'-di-p-tolylcarbodiimide,
[0046] p-phenylene-bis-di-o-tolylcarbodiimide, [0047]
p-phenylene-bis-dicyclohexylcarbodiimide, [0048]
hexamethylene-bis-dicyclohexylcarbodiimide, [0049]
ethylene-bis-diphenylcarbodiimide, [0050] N,N'-benzylcarbodiimide,
[0051] N-octadecyl-N'-phenylcarbodiimide, [0052]
N-benzyl-N'-phenylcarbodiimide, [0053]
N-octadecyl-N'-tolylcarbodiimide, [0054]
N-cyclohexyl-N'-tolylcarbodiimide, [0055]
N-phenyl-N'-tolylcarbodiimide, [0056]
N-benzyl-N'-tolylcarbodiimide, [0057]
N,N'-di-o-ethylphenylcarbodiimide, [0058]
N,N'-di-p-ethylphenylcarbodiimide, [0059]
N,N'-di-o-isopropylphenylcarbodiimide, [0060]
N,N'-di-p-isopropylphenylcarbodiimide, [0061]
N,N'-di-o-isobutylphenylcarbodiimide, [0062]
N,N'-di-p-isobutylphenylcarbodiimide, [0063]
N,N'-di-2,6-diethylphenylcarbodiimide, [0064]
N,N'-di-2-ethyl-6-isopropylphenylcarbodiimide, [0065]
N,N'-di-2-isobutyl-6-isopropylphenylcarbodiimide, [0066]
N,N'-di-2,4,6-trimethylphenylcarbodiimide, [0067]
N,N'-di-2,4,6-triisopropylphenylcarbodiimide, [0068]
N,N'-di-2,4,6-triisobutylphenylcarbodiimide, [0069]
diisopropylcarbodiimide, [0070] dimethylcarbodiimide, [0071]
diisobutylcarbodiimide, [0072] dioctylcarbodiimide, [0073]
t-butylisopropylcarbodiimide, [0074]
di-.beta.-naphthylcarbodiimide, [0075] di-t-butylcarbodiimide, and
[0076] aromatic polycarbodiimide (for example, trade name:
Stabaksol I manufactured by SUMIKA BAYER URETHANE CO., LTD.). These
carbodiimide compounds may be used alone. However, the carbodiimide
compounds may be used in combination. In the present invention,
N,N'-di-2,6-diisopropylphenylcarbodiimide having a high hydrolysis
inhibiting effect is particularly preferable.
[0077] The proportion of the carbodiimide compound should be 0.1 to
5 parts by mass based on 100 parts by mass of the biodegradable
polyester resin, and preferably 0.5 to 3 parts by mass. If the
proportion is less than 0.1 part by mass, it is impossible to
obtain long-term moisture heat resistance and appearance stability
intended by the present invention. Even if the proportion is more
than 5 parts by mass, a higher effect is not observed.
[0078] In the present invention, the biodegradable resin
composition contains the layered silicate in order to enhance the
strength and gas barrier property or the like of the biodegradable
resin composition. The layered silicate is one type of a swellable
lamellar clay mineral, and specific examples thereof include
smectite, vermiculite and swellable fluoromica. Examples of the
smectite include montmorillonite, beidellite, hectorite and
saponite. Examples of the swellable fluoromica include Na-type
tetrasilicic fluoromica, Na-type taeniolite and Li-type taeniolite.
Other usable examples include layered silicates such as canemite,
macatite, magadiite and kenyaite which contain neither aluminum nor
magnesium. A natural layered silicate can be preferably employed as
the layered silicate. Besides the natural layered silicates, a
synthetic layered silicate may be employed. The synthetic layered
silicate may be prepared by any of a melt process, an intercalation
process and a hydrothermal process. Any of these layered silicates
may be used alone. Layered silicates of different types, different
production sites and different particle diameters may be used in
combination.
[0079] For enhancing the dispersibility of the layered silicate in
the biodegradable polyester resin which is the major component of
the biodegradable resin composition of the present invention to
enhance the gas barrier property, it is preferable that primary,
secondary, tertiary or quaternary ammonium ions, pyridinium ions,
imidazolium ions or phosphonium ions are ionically bonded between
layers of the layered silicate. The primary, secondary and tertiary
ammonium ions are prepared by protonating primary, secondary and
tertiary amines corresponding thereto. Examples of the primary
amines include octylamine, dodecylamine and octadecylamine.
Examples of the secondary amines include dioctylamine,
methyloctadecylamine and dioctadecylamine. Examples of the tertiary
amines include trioctylamine, dimethyldodecylamine and
didodecylmonomethylamine. Examples of the quaternary ammonium ions
include dihydroxyethylmethyloctadecylammonium,
dihydroxyethylmethyldodecylammonium, tetraethylammonium,
octadecyltrimethylammonium, dimethyldioctadecylammonium,
hydroxyethyldimethyloctadecylammonium,
hydroxyethyldimethyldodecylammonium,
benzyldihydroxyethyldodecylammonium,
benzyldihydroxyethyloctadecylammonium,
methyldodecylbis(polyethyleneglycol)ammonium, and
methyldiethyl(polypropylene glycol)ammonium. Examples of the
phosphonium ions include tetraethylphosphonium,
tetrabutylphosphonium, hexadecyltributylphosphonium,
tetrakis(hydroxylmethyl)phosphonium and
2-hydroxyethyltriphenylphosphonium. Of these, a layered silicate
treated with ammonium ions or phosphonium ions such as
dihydroxyethylmethyloctadecylammonium,
dihydroxyethylmethyldodecylammonium,
hydroxyethyldimethyloctadecylammonium,
hydroxyethyldimethyldodecylammonium,
methyldodecylbis(polyethyleneglycol)ammonium,
methyldiethyl(polypropyleneglycol)ammonium and
2-hydroxyethyltriphenylphosphonium having at least one hydroxyl
group in its molecule is particularly preferable because of the
strong affinity for the biodegradable polyester resin and the
improved dispersibility. Any of these ionic compounds may be used
either alone or in combination.
[0080] A method for treating the layered silicate with the primary,
secondary, tertiary or quarternary ammonium ions or the phosphonium
ions is not particularly limited. For example, inorganic ions
between the layers of the layered silicate are first ion-exchanged
with ammonium ions or phosphonium ions by dispersing the layered
silicate in water or alcohol, adding the primary, secondary or
tertiary amines and an acid (hydrochloric acid or the like), a
quarternary ammonium salt, or a phosphonium salt and stirring the
resulting mixture. Then, the resulting product is filtered, rinsed
and dried.
[0081] The proportion of the layered silicate should be 0.1 to 10
parts by mass based on 100 parts by mass of the biodegradable
polyester resin, preferably 0.5 to 8 parts by mass, and more
preferably 2 to 5 parts by mass. If the proportion is less than 0.1
part by mass, it is impossible to obtain the enhanced effect of
heat resistance and gas barrier property intended by the present
invention. If the proportion is more than 10 parts by mass, the
moisture heat resistance and moldability of the biodegradable
polyester resin tend to be reduced.
[0082] In the present invention, this biodegradable resin
composition contains a phosphite organic compound for suppressing
the coloration of the biodegradable resin composition and applying
heat resistance and moisture heat resistance to the biodegradable
resin composition. Herein, examples of the phosphite organic
compounds include tris(2,4-di-tert-butylphenyl)phosphite (trade
name: IRGAFOS168 manufactured by Ciba Speciality Chemicals, Inc.),
bis(2,4-di-tert-butylphenyl)pentaerythritoldiphosphite (trade name:
IRGAFOS12 manufactured by Ciba Speciality Chemicals, Inc.),
bis[2,4-bis(1,1-dimethylethyl)-6-methylphenyl]ethyl ester phosphite
(trade name: IRGAFOS38 manufactured by Ciba Speciality Chemicals,
Inc.),
tetrakis(2,4-di-tert-butylphenyl)[1,1-biphenyl]4,4'-diylbisphosphonite
(trade name: IRGAFOS P-EPQ manufactured by Ciba Speciality
Chemicals, Inc.),
3,9-bis(p-nonylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5,5]u-
ndecane (trade name: Adeka Stub PEP-4C manufactured by ASAHI DENKA
CO., LTD.), O,O'-dialkyl(C=8 to 18)pentaerythritoldiphosphite
(trade name: Adeka Stub PEP-8, PEP-8W manufactured by ASAHI DENKA
CO., LTD.), bis(2,4-di-tert-butylphenyl)pentaerythritoldiphosphite
(trade name: Adeka Stub PEP24G manufactured by ASAHI DENKA CO.,
LTD.),
bis(2,6-di-tort-butyl-4-methylphenyl)pentaerythritol-di-phosphite
(trade name: Adeka Stub PEP36 and PEP-36Z manufactured by ASAHI
DENKA CO., LTD.),
2,2'-methylenebis(4,6-di-tert-butylphenyl)-2-ethylhexylphosphite
(trade name: Adeka Stub HP-10 manufactured by ASAHI DENKA CO.,
LTD.), tris(2,4-di-tert-butylphenylphosphite) (trade name: Adeka
Stub 2112 manufactured by ASAHI DENKA CO., LTD.),
4,4'-butylidene-bis(6-tert-butyl-3-methylphenyl-ditridecylphosphite)
(trade name: Adeka Stub 260 manufactured by ASAHI DENKA CO., LTD.),
hexaalkyl or [trialkyl(C=8 to
18)tris(alkyl(C=8,9)phenyl)]1,1,3-tris(3-t-butyl-6-methyl-4-oxyphenyl)-3--
methylpropanetriphosphite (trade name: Adeka Stub 522A manufactured
by ASAHI DENKA CO., LTD.), di or mono(dinonylphenyl)mono or
di(p-nonylphenyl)phosphite (trade name: Adeka Stub 329K
manufactured by ASAHI DENKA CO., LTD.), trisnonylphenylphosphite
(trade name: Adeka Stub 1178 manufactured by ASAHI DENKA CO.,
LTD.),
(1-methylethylidene)-di-4,1-phenylene-tetra-C12-15-alkylphosphite
(trade name: Adeka Stub 1500 manufactured by ASAHI DENKA CO.,
LTD.), 2-ethylhexyl-diphenylphosphite (trade name: Adeka Stub C
manufactured by ASAHI DENKA CO., LTD.), diphenylisodecylphosphite
(trade name: Adeka Stub 135A manufactured by ASAHI DENKA CO.,
LTD.), triisodecylphosphite (trade name: Adeka Stub 3010
manufactured by ASAHI DENKA CO., LTD.), triphenylphosphite (trade
name: TPP manufactured by ASAHI DENKA CO., LTD.), and hydrogenated
bisphenol Apentaerythritolphosphite polymer (trade name: JPH3800
manufactured by JOHOKU CHEMICAL CO., LTD.).
[0083] Of these, pentaerythritol diphosphite (PEP 24G),
bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol-di-phosphite
(PEP36, PEP-36Z), tris(2,4-di-tert-butylphenylphosphite)(2112),
hydrogenated bisphenol Apentaerythritol phosphite polymer (JPH3800)
or the like are more preferable. These may be used either alone or
in combination.
[0084] The proportion of the phosphite organic compound should be
0.01 to 5 parts by mass based on 100 parts by mass of the
biodegradable polyester resin, and preferably 0.05 to 2 parts by
mass. If the proportion is less than 0.01 part by mass, it is
impossible to obtain the suppression of coloration, the heat
resistance and the moisture heat resistance, which are intended by
the present invention. If the proportion is more than 5 parts by
mass, the physical properties of the resin composition are reduced
by the decomposition of the phosphite organic compound.
[0085] The resin composition of the present invention can contain
the phosphite organic compound, as well as at least one additive
selected from the group consisting of a hindered phenol compound, a
benzotriazole compound, a triazine compound and a hindered amine
compound. Since this additive can provide the same effect as that
of the case where the phosphite organic compound is used alone, the
additive is useful when the content of the phosphite compound is
limited by restriction or the like. In using this additive, the
total proportion of the additive and phosphite organic compound
should be 0.01 to 5 parts by mass based on 100 parts by mass of the
biodegradable polyester resin, and preferably 0.05 to 2 parts by
mass. If the proportion is less than 0.01 part by mass, it is
impossible to obtain the suppression of coloration, the heat
resistance and the moisture heat resistance, which are intended by
the present invention. If the proportion is more than 5 parts by
mass, the physical properties are reduced and the coloration is
caused by these compounds and decomposed substances.
[0086] Examples of the hindered phenol compounds in the present
invention include
pentaerythritoltetrakis[3-(3,5-di-tert-butyl-hydroxyphenyl)propio-
nate] (trade name: IRGANOX 1010 manufactured by Ciba Speciality
Chemicals, Inc.),
thiodiethylenebis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]
(trade name: IRGANOX 1035 manufactured by Ciba Speciality
Chemicals, Inc.),
octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (trade
name: IRGANOX 1076 manufactured by Ciba Speciality Chemicals,
Inc.),
N,N'-hexane-1,6-diylbis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionamide-
] (trade name: IRGANOX 1098 manufactured by Ciba Speciality
Chemicals, Inc.), benzene propanoic acid,
3,5-bis(1,1-dimethylethyl)-4-hydroxy, C7-C9 side-chain alkylester
(trade name: IRGANOX 1135 manufactured by Ciba Speciality
Chemicals, Inc.), 2,4-dimethyl-6-(1-methylpentadecyl)phenol (trade
name: IRGANOX 1141 manufactured by Ciba Speciality Chemicals,
Inc.),
diethyl[{3,5-bis(1,1-dimethylethyl)-4-hidoroxyphenyl}methyl]phosphonate
(trade name: IRGANOX 1222 manufactured by Ciba Speciality
Chemicals, Inc.),
3,3',3'',5,5',5''-hexa-tert-butyl-a,a',a''-(mesitylene-2,4,6-triyl-
)tri-p-cresol (trade name: IRGANOX 1330 manufactured by Ciba
Speciality Chemicals, Inc.), a mixture (trade name: IRGANOX 1425WL
manufactured by Ciba Speciality Chemicals, Inc.) of calcium
diethylbis[[[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]phosphonat-
e] and polyethylene wax, 4,6-bis(octylthiomethyl)-o-cresol (trade
name: IRGANOX 1520L manufactured by Ciba Speciality Chemicals,
Inc.),
ethylenebis(oxyethylene)bis[3-(tert-buyl-4-hydroxy-m-tolyl)propionate]
(trade name: IRGANOX 245 manufactured by Ciba Speciality Chemicals,
Inc.),
1,6-hexanediol-bis[3(3,5-di-t-butyl-4-hydroxyphenyl)propionate]
(trade name: IRGANOX 259 manufactured by Ciba Speciality Chemicals,
Inc.), 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanuric
acid (trade name: IRGANOX 3114 manufactured by Ciba Speciality
Chemicals, Inc.),
1,3,5-tris[(4-tert-butyl-3-hydroxy-2,6-xylyl)methyl]-1,3,5-triazin-
e-2,4,6(1H,3H,5H)-trione (trade name: IRGANOX 3790 manufactured by
Ciba Speciality Chemicals, Inc.), a reaction product (trade name:
IRGANOX 5057 manufactured by Ciba Speciality Chemicals, Inc.) of
N-phenylbenzenamine and 2,4,4-trimethylpentene,
6-(4-hydroxy-3,5-di-t-butylanilino)-2,4-bisoctylthio-1,3,5-triazine
(trade name: IRGANOX 565 manufactured by Ciba Speciality Chemicals,
Inc.), 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanuric
acid (trade name: Adeka Stub AO-20 manufactured by ASAHI DENKA CO.,
LTD.), 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane
(trade name: Adeka Stub AO-30 manufactured by ASAHI DENKA CO.,
LTD.), 4,4'-butylidenebis(6-tert-butyl-3-methylphenol) trade name:
Adeka Stub AO-40 manufactured by ASAHI DENKA CO., LTD.),
3-(4'-hydroxy-3',5'-di-tert-butylphenyl)propionic acid-n-octadecyl
(trade name: Adeka Stub AO-50 manufactured by ASAHI DENKA CO.,
LTD.),
pentaerythritoltetrakis[3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionat-
e] (trade name: Adeka Stub AO-60 manufactured by ASAHI DENKA CO.,
LTD.),
triethyleneglycolbis[3-(3-t-butyl-4-hydroxy-5-methylphenyl)propionate]
(trade name: Adeka Stub AO-70 manufactured by ASAHI DENKA CO.,
LTD.),
3,9-bis[1,1-dimethyl-2-[.beta.-(3-t-butyl-4-hydroxy-5-methylphenylpropion-
yloxy)ethyl]2,4,8,10-tetraoxspiro[5,5]-undecane (trade name: Adeka
Stub AO-80 manufactured by ASAHI DENKA CO., LTD.),
1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene
(trade name: Adeka Stub AO-330 manufactured by ASAHI DENKA CO.,
LTD.), and
2,2-oxamidebis-[ethyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate]
(trade name: Naugard XL-1 manufactured by Crompton-Uniroyal
Chemical).
[0087] Of these, particularly,
pentaerythritoltetrakis[3-(3,5-di-tert-butyl-hydroxyphenyl)propionate]
(IRGANOX 1010),
1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene
(AO-330) or the like are preferably used. These may be used either
alone or in combination.
[0088] Examples of the benzotriazole compounds include
2-(2'-hydroxy-5'-methylphenyl)benzotriazole (trade name: TINUVIN P
manufactured by Ciba Speciality Chemicals, Inc.),
2-(2H-benzotriazole-2-yl)-4,6-bis(1-methyl-1-phenylethyl)phenol
(trade name: TINUVIN234 manufactured by Ciba Speciality Chemicals,
Inc.), and
2-(2'-hydroxy-3'-t-butyl-5'-methylphenyl)-5-chlorobenzotriazole
(trade name: TINUVIN326 manufactured by Ciba Speciality Chemicals,
Inc.).
[0089] Examples of the triazine compounds include
2-(4,6-diphenyl-1,3,5-triazine-2-yl)-5-[(hexyl)oxy]-phenol (trade
name: TINUVIN1577FF manufactured by Ciba Speciality Chemicals,
Inc.), and
2-[4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine-2-yl]-5-(octyloxy)phenol
(trade name: UV-1164 manufactured by Cytec Industries).
[0090] Examples of the hindered amine compounds include
poly[{6-(1,1,3,3-tetramethylbutyl)amino-1,3,5-triazine-2,4-diyl}{(2,2,6,6-
-tetramethyl-4-piperidyl)imino}hexamethylene{(2,2,6,6-tetramethyl-4-piperi-
dyl)imino}] (trade name: CHIMASSORB944FDL manufactured by Ciba
Speciality Chemicals, Inc.).
[0091] It is preferable that the biodegradable resin composition of
the present invention has a strength-retaining rate of not less
than 60% when 300 hours pass at 60.degree. C. and at a relative
humidity of 95%. Herein, the strength-retaining rate is prepared by
producing a test piece using a resin composition, measuring the
test piece based on ASTM-D790, and calculating the retaining rate
of the flexural strength before and after being treated.
[0092] The resin composition of the present invention has excellent
color tone, and preferably, the resin composition has a YI value of
not more than 25. If the YI value is more than this value, the
commercial value, for example, of a molded body molded by the resin
composition is reduced. Herein, the YI value means yellowness
calculated from three tristimulus values. The larger the YI value
is, the more intensive the yellowness is, and the smaller the YI
value is, the weaker the yellowness is.
[0093] Examples of methods for adding a carbodiimide compound, a
phosphite organic compound and the above additive in producing the
biodegradable polyester resin of the present invention include a
method for melt-kneading the biodegradable polyester resin, the
carbodiimide compound, the phosphite organic compound and the
additive using an ordinary kneader, and a method for polymerizing a
monomer of the biodegradable polyester in the presence of a
predetermined amount of the carbodiimide compound, phosphite
organic compound and additive with respect to the monomer to
provide the biodegradable polyester resin composition. Of these,
the former method is preferable because of less reduction of the
molecular weight of the biodegradable polyester resin and simple
addition or the like.
[0094] Examples of the methods for adding the layered silicate in
producing the biodegradable resin composition of the present
invention include a method for adding the layered silicate when
polymerizing the biodegradable polyester resin, a method for adding
the layered silicate when melt-kneading the biodegradable polyester
resin, and a method for adding the layered silicate when molding a
molded body. Of these, it is preferable to add the layered silicate
when melt-kneading the biodegradable polyester resin or molding the
molded body. Examples of the methods for adding the layered
silicate when melt-kneading the biodegradable polyester resin and
when molding the molded body include a method for previously
dry-blending a resin and a layered silicate and supplying the
blended mixture to an ordinary kneader or an injection molding
machine, and a method for adding the layered silicate during
kneading using a side feeder.
[0095] In melt-kneading the biodegradable polyester resin, an
ordinary extruder such as a single screw extruder, a twin screw
extruder, a roll kneader and Brabender can be used. The use of the
twin screw extruder is preferable for improving the
dispersibilities of the layered silicate, carbodiimide compound,
phosphite organic compound and additive.
[0096] Magnesium stearate, a phosphate ester surface-active agent,
and a partially saponified ester of a montanic acid or the like may
be added to the biodegradable polyester resin for improving the
dispersibility of the layered silicate. For improving this
dispersibility, a resin may be denatured with anhydrous maleic acid
or the like and a polar group may be introduced.
[0097] A heat stabilizer, an oxidation inhibitor, a pigment, a
weather-proof agent, a flame retarder, a plasticizer, a lubricant,
a release agent, an antistatic agent, a filler and a dispersant or
the like other than the specified ones in present invention may be
added to the resin composition of the present invention, as long as
the effect of the present invention is not damaged by the addition.
Examples of the heat stabilizer and the oxidation inhibitor include
sulfur compounds, copper compounds and halides of alkali metals,
which may be used as a mixture. These additives are generally added
in melt-kneading or polymerizing. Exemplary inorganic fillers among
the fillers include talc, calcium carbonate, zinc carbonate,
walastonite, silica, alumina, magnesium oxide, calcium silicate,
sodium aluminate, calcium aluminate, sodium aluminosilicate,
magnesium silicate, glass balloon, carbon black, zinc oxide,
antimony trioxide, zeolite, hydrotalcite, metal fibers, metal
whisker, ceramic whisker, potassium titanate, boron nitride,
graphite, glass fibers and carbon fibers. Exemplary organic fillers
among the fillers include naturally occurring polymers such as
starch, cellulose particles, wood powder, bean curd lees, chaff,
bran and kenaf and denatured materials thereof.
[0098] To the biodegradable resin composition of the present
invention, a non-biodegradable resin such as polyamide (nylon),
polyethylene, polypropylene, polybutadiene, polystyrene, an AS
resin, an ABS resin, polyacrylic acid, polyacrylic acid ester,
polymethacrylic acid, polymethacrylic acid ester, polyethylene
terephthalate, polyethylenenaphthalate, polycarbonate and a
copolymer thereof may be added as long as the effect of the present
invention is not damaged.
[0099] The resin composition of the present invention can be used
as various molded bodies by known molding processes such as
injection molding, blow molding and extrusion molding.
[0100] For the injection molding process, it is possible to employ
an ordinary injection molding process, a gas injection molding
process and an injection press molding method. A cylinder
temperature in the injection molding process, that is, the molding
temperature should be not less than the melting point (Tm) or
fluidization temperature of polylactic acid, is preferably 180 to
230.degree. C., and more preferably 190 to 220.degree. C. If the
molding temperature is too low, the flowability of the resin is
reduced to cause poor molding or overloading of a molding
apparatus. Conversely, if the molding temperature is too high, the
polylactic acid is decomposed, so that the resulting molded body
disadvantageously has a reduced strength or is colored. On the
other hand, the mold temperature is preferably not more than
Tg-10.degree. C. when the mold temperature is not more than the
glass transition temperature Tg of the resin composition. The mold
temperature may not be less than Tg and can not be more than
Tm-30.degree. C. for accelerating the crystallization for
improvement of the rigidity and heat resistance of the molded
body.
[0101] For the blow molding process, it is possible to employ a
direct blowing method in which material chips are directly molded,
an injection blow molding method in which a preform (bottomed
parison) is first injection-molded and then blow-molded, and a
stretch blow molding method. For the injection blow molding method,
it is also possible to employ a hot parison method in which a
preform is blow-molded immediately after formation of the preform,
or a cold parison method in which a preform is once cooled and
unmolded and then heated again to be blow-molded.
[0102] As the extrusion process, a T-die technique and a circular
die technique or the like may be employed. The extrusion
temperature should be not less than the melting point (Tm) or
fluidization temperature of the polylactic acid as the raw
material. The extrusion temperature is preferably in the range of
180 to 230.degree. C., more preferably 190 to 220.degree. C. If the
extrusion temperature is too low, the operation is unstabilized or
overloaded. Conversely, if the extrusion temperature is too high,
the polylactic acid is decomposed, so that the extrusion-molded
body disadvantageously has a reduced strength or is colored. A
sheet or a pipe or the like can be produced by extrusion
molding.
[0103] Specifically, the sheet or pipe prepared by the extrusion
process, may be used as a material sheet for deep drawing, a
material sheet for batch foaming, cards such as credit cards, desk
pads, clear files, straws, and agricultural/horticultural rigid
pipes or the like. A food container, an agricultural/horticultural
container, a blister package and a press-through package or the
like may be produced by a deep drawing process by vacuum-forming,
air-pressure-forming or vacuum-air-pressure-forming the sheet. The
deep-drawing temperature and the heat treatment temperature are
preferably Tg+20.degree. C. to Tg+100.degree. C. If the deep
drawing temperature is less than Tg+20.degree. C., the deep drawing
is difficult. Conversely, if the deep drawing temperature is more
than Tg+100.degree. C., the polylactic acid is decomposed; the
resulting container has an uneven wall thickness and an uneven
orientation thereby to have a reduced impact resistance. The shapes
of the food container, the agricultural/horticultural container,
the blister package and the press-through package are not
particularly limited, but the sheet is preferably drawn to a depth
of not less than 2 mm for containing food stuff, articles, and
pharmaceutical products or the like. The thicknesses of the
containers are not particularly limited, but preferably not less
than 50 .mu.m more preferably 150 to 500 .mu.m, in consideration of
strength. Specific examples of the food container include trays for
perishable food, containers for instant food, containers for fast
food and containers for a lunch box. Specific examples of the
agricultural/horticultural container include seedling pots.
Specific examples of the blister package include containers for
packaging foods. Other examples of the package include packages for
various articles such as stationery, toys and dry batteries.
[0104] Other examples of the molded bodies produced using the resin
composition of the present invention include tableware such as
dishes, bowls, pots, chopsticks, spoons, forks and knives; fluid
containers; container caps; stationery such as rulers, writing
utensils, clear cases and CD cases; daily commodities such as sink
strainers, wastebaskets, washbowls, toothbrushes, hair combs and
dress hangers; agricultural/horticultural materials such as flower
pots and seedling pots; toys such as plastic models; electrical
appliance resin components such as air conditioner panels and
housings; and automotive resin components such as bumpers, interior
panels and door trims. The shape of the fluid container is not
particularly limited, but the fluid container preferably has a
depth of not less than 20 mm for containing a fluid. The wall
thickness of the container is not particularly limited, but is not
less than 0.1 mm, preferably 0.1 to 5 mm, in view of strength.
Specific examples of the fluid container include drinking cups and
bottles for dairy products, soft drinks and alcoholic beverages;
temporary storage containers for condiments such as soy source,
Worcester source, mayonnaise, ketchup and cooking oil; containers
for shampoo and rinse agents; containers for cosmetics; and
containers for agricultural chemicals.
[0105] The molded body made of the resin composition of the present
invention is subjected to a heat treatment to accelerate the
crystallization of the molded body and thereby the heat resistance
can be also enhanced. The heat treatment temperature is usually not
less than Tg and not more than Tm.
[0106] The resin composition of the present invention can be also
made of fibers. Although the producing method is not particularly
limited, a method for melt spinning and drawing is preferable. The
melt spinning temperature is preferably 160.degree. C. to
260.degree. C. If the melt spinning temperature is less than
160.degree. C., the melting extrusion tends to be difficult. On the
other hand, when the melt spinning temperature is more than
260.degree. C., the resin composition is remarkably decomposed, and
thereby fibers having high strength tend to be hardly obtained. The
melt-spun fiber thread line may be drawn at a temperature of not
less than Tg so as to be set to the intended fiber diameter. The
obtained fibers are used as fibers for clothing, fibers for
industrial materials, and fibers for short fiber nonwoven or the
like.
[0107] The resin composition of the present invention can be also
developed to filament nonwoven fabric. Although the producing
method is not particularly limited, examples thereof include a
method for forming the resin composition into fibers by a high
speed fiber spinning method, depositing and webbing the fibers, and
making the web into fabrics using heat pressure bonding method or
the like.
EXAMPLES
[0108] The present invention will hereinafter be described more
specifically by way of examples thereof. However, the present
invention is not limited to the following examples.
[Measuring Method or the Like]
[0109] Measuring methods or the like used for evaluating the
following examples and comparative examples are as follows.
(1) Flexural Strength:
[0110] A resin composition was injection-molded to obtain a molded
piece of 150 mm.times.13 mm.times.3 mm. The molded piece was
subjected to an annealing treatment, and was used as a sample. The
flexural strength was measured in conformity with ASTM-D790 by
applying a load at a deformation rate of 1 mm/min. The production
conditions of the molded pieces are as follows.
Injection Molding Condition:
[0111] By means of an injection molding machine (IS-80G
manufactured by Toshiba Machine), a cylinder temperature, a metal
mold temperature, an injection pressure, an injection time, a
cooling time and an interval are respectively set to 190 to
170.degree. C., 15.degree. C., 60%, 20 seconds, 20 seconds and 2
seconds. As the metal mold, a metal mold for 1/8 inch three-point
bending dumbbell test piece of ASTM standard was used.
Annealing Treatment Condition:
[0112] The molded pieces were heated for 30 minutes in an oven of
120.degree. C.
(2) Hydrolysis Resistance Evaluation
[0113] Samples subjected to an injection molding and an annealing
treatment in the same manner as in the item (1) were stored at
60.degree. C. and at a relative humidity of 95% for 300 hours and
500 hours using a thermo-hygrostat (trade name: IG400, manufactured
by Yamato Scientific Co., Ltd.). The flexural strengths were then
measured in the same manner as in the item (1), and the
strength-retaining rates were calculated to evaluate hydrolysis
resistance.
[0114] The strength-retaining rate (%) was calculated as
(strength-retaining rate)=(strength after being stored)/(strength
before being stored).times.100.
(3) Yellowness (YI Value):
[0115] A color-difference meter Z-.SIGMA.90 manufactured by Nippon
Densyoku Industries, Co. was used. A glass cell having a diameter
of 30 mm and a length of 12 mm was filled with pellets each having
a height of 3 mm, a width of 3 mm and a thickness of 1.5 mm to
measure the yellowness.
(4) Appearance:
[0116] Visual evaluation was performed. The appearance having no
change was evaluated as "very good". The appearance having some
blanching occurred but having no deposit of metal salts and
low-molecular weight substances was evaluated as "good"; and the
appearance having the deposited metal salts and low-molecular
weight substances was evaluated as "poor".
(5) Oxygen Permeability Coefficient:
[0117] A sheet-shaped sample (thickness: 200 to 300 .mu.m) was
produced by inserting resin composition pellets with a pair of
aluminum plates, heat-pressing the pellets at 190.degree. C. for
150 seconds, and cold-pressing the heat-pressed article at
25.degree. C. for 20 seconds. A measuring sample was prepared by
previously humidity-controlling the sheet-shaped sample at
20.degree. C. and at a relative humidity of 90% for 24 hours. The
oxygen permeability of this measuring sample was measured by a
differential pressure method using a differential pressure gas
permeability meter (GTR-30XAU type manufactured by Yanaco). The
oxygen permeability coefficient (mlmm/m.sup.2dayMPa) was calculated
by
(oxygen permeability coefficient)=(oxygen
permeability).times.(sample thickness).
The value of the oxygen permeability coefficient was an indicator
of gas barrier property. The smaller this value is, the more
excellent the gas barrier property is.
[Raw Materials]
[0118] Various raw materials used in the following examples and
comparative examples are shown.
(1) Biodegradable Resin
[0119] Resin A: polylactic acid (trade name: Nature Works
manufactured by Cargill Dow, weight average molecular weight (MW):
190,000, melting point: 170.degree. C.)
[0120] Resin B: terephthalic acid/adipic acid/1,4-butanediol
copolymer (trade name: Ecoflex manufactured by BASF, melting point:
108.degree. C., melt flow rate (MFR): 5 g/10 minutes (190.degree.
C., load: 2.16 kg))
(2) Carbodiimide Compound
[0121] CDI: N,N'-di-2,6-diisopropylphenylcarbodiimide (trade name:
Stabaksol I manufactured by SUMIKA BAYER URETHANE CO., LTD.)
(3) Phosphite Organic Compound
[0122] PEP-36:
bis(2,6-di-tert-butyl-4-methylphenyl)-pentaerythritol-di-phosphite
(trade name: Adeka Stub PEP36 manufactured by ASAHI DENKA CO.,
LTD.)
[0123] JPH3800: hydrogenated bisphenol Apentaerythritol phosphite
polymer (trade name: JPH3800 manufactured by JOHOKU CHEMICAL CO.,
LTD.)
[0124] 2112: tris(2,4-di-tert-butylphenylphosphite) (trade name:
Adeka Stub 2112 manufactured by ASAHI DENKA CO., LTD.)
(4) Hindered Phenol Compound
[0125] AO-330:
1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene
(trade name: Adeka Stub AO-330 manufactured by ASAHI DENKA CO.,
LTD.)
[0126] XL-1:
2,2-oxamidobis-[ethyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate]
(trade name: Naugard XL-1 manufactured by Crompton-Uniroyal
Chemical)
(5) Benzotriazole Compound
[0127] T-234:
2-(2H-benzotriazole-2-yl)-4-6-bis(1-methyl-1-phenylethyl)phenol
(trade name: TINUVIN234 manufactured by Ciba Speciality Chemicals,
Inc.)
[0128] T-326:
2-(2'-hydroxy-3'-t-butyl-5'-methylphenyl)-5-chlorobenzotriazole
(trade name: TINUVIN326 manufactured by Ciba Speciality Chemicals,
Inc.)
(6) Triazine Compound
[0129] UV-1164:
2-[4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine-2-yl]-5-(octyloxy)phenol
(trade name: UV-1164 manufactured by Cytec Industries)
(7) Hindered Amine Compound
[0130] CHIMASSOR:
poly[{6-(1,1,3,3-tetra-methylbutyl)amino-1,3,5-triazine-2,4-diyl}{(2,2,6,-
6-tetramethyl-4-piperidyl)imino}hexamethylene{(2,2,6,6-tetramethyl-4-piper-
idyl)imino}] (trade name: CHIMASSORB944FDL manufactured by Ciba
Speciality Chemicals, Inc.)
(8) Layered Silicate
[0131] MEE: A swellable synthetic fluoromica having
dihydroxyethylmethyldodecyl ammonium ions between layers thereof
(trade name: SOMASIF MEE manufactured by CO-OP CHEMICAL CO., LTD.,
average particle diameter: 6.2 .mu.m)
[0132] MTE: A swellable synthetic fluoromica having methytrioctyl
ammonium ions between layers thereof (trade name: SOMASIF MTE
manufactured by CO-OP CHEMICAL CO., LTD., average particle
diameter: 6.2 .mu.m)
[Production of Resin]
[0133] A PCM-30 type twin screw extruder manufactured by IKEGAI
CORPORATION was used for melt-kneading. The screw diameter was 30
mm, and the average groove depth was 2.5 mm.
Example 1
[0134] 100 parts by mass of a resin A, 2 parts by mass of CDI, 4
parts by mass of MEE and 0.5 parts by mass of PEP 36 were
dry-blended, melt-mixed at 190.degree. C. under conditions of the
rotation speed (rps) of the screw of 200 rpm (=3.3 rps) and the
retention time of 1.6 minutes, extruded, processed into a pellet
shape, and dried to obtain a resin composition. The evaluation
results of the physical properties and hydrolysis resistance of the
obtained composition are shown in Table 1.
Examples 2 to 22 and Comparative Examples 1 to 11
[0135] Components and blending rate thereof each of examples and
comparative examples were changed as shown in Table 1. Otherwise,
in the same manner as in Example 1, compositions were obtained. The
evaluation results of the physical properties and hydrolysis
resistance of the obtained compositions are shown in Table 1.
[0136] In example 21 and comparative example 10, 90 parts by mass
of a resin A and 10 parts by mass of a resin B of a pellet-shaped
were dry-blended and used before the resins A, B were supplied to
an extruder.
TABLE-US-00001 TABLE 1 Main resin composition (amount shows part by
mass) Biodegradable Carbodiimide Phosphite organic resin compound
Layered silicate compound Other additives Type Amount Type Amount
Type Amount Type Amount Type Amount Examples 1 A 100 CD I 2 MEE 4
PEP36 0.5 2 A 100 CD I 2 MEE 4 PEP36 1 3 A 100 CD I 2 MEE 4 PEP36 2
4 A 100 CD I 2 MEE 4 PEP36 0.1 5 A 100 CD I 2 MEE 0.5 PEP36 0.5 6 A
100 CD I 2 MEE 2 PEP36 0.5 7 A 100 CD I 2 MEE 8 PEP36 1 8 A 100 CD
I 0.5 MEE 4 PEP36 0.5 9 A 100 CD I 4 MEE 4 PEP36 0.5 10 A 100 CD I
2 MEE 4 JPH3800 0.1 11 A 100 CD I 2 MEE 4 JPH3800 0.5 12 A 100 CD I
2 MEE 4 JPH3800 1 13 A 100 CD I 2 MEE 4 PEP36 0.5 AO-330 0.5 14 A
100 CD I 2 MEE 4 PEP36 1 AO-330 1 15 A 100 CD I 2 MEE 4 PEP36 0.5
T-234 0.5 16 A 100 CD I 2 MEE 4 PEP36 0.5 UV1164 0.5 17 A 100 CD I
2 MEE 4 PEP36 0.5 AO-330/XL-1 Each of 0.25 18 A 100 CD I 2 MEE 4
2112 0.5 AO-330 0.5 19 A 100 CD I 2 MEE 4 JPH3800 0.5 AO-330 0.5 20
A 100 CD I 2 MTE 4 PEP36 0.5 AO-330 0.5 21 A/B 90/10 CD I 2 MEE 4
PEP36 0.5 AO-330 0.5 22 A 100 CD I 2 MEE 4 PEP36 0.5 CHIMASSOR 0.5
Comparative 1 A 100 examples 2 A 100 CD I 2 3 A 100 MEE 4 4 A 100
CD I 2 MEE 4 5 A 100 MEE 4 PEP36 0.5 6 A 100 CD I 2 MEE 4 AO-330
0.5 7 A 100 CD I 2 MEE 4 T-326 0.5 8 A 100 CD I 2 MEE 4 UV1164 0.5
9 A 100 CD I 2 MTE 4 10 A/B 90/10 CD I 2 MEE 4 11 A 100 CD I 2 MEE
4 CHIMASSOR 0.5 Characteristics of molded body made of resin
composition Hydrolysis resistance Oxygen evaluation permeability
(60.degree. C., 95% RH, 300 hours) Appearance evaluation Color
Flexural coefficient Flexural strength (60.degree. C., 95% RH, 500
hours) tone strength ml mm/m.sup.2 Retaining Flexural strength
Appearance YI MPa day MPa MPa rate (%) MPa evaluation Examples 1 21
108.9 122 84.0 65.2 33.0 Good 2 11 119.6 110 104.2 87.1 89.6 Very
good 3 7 125.0 130 98.1 78.5 85.3 Very good 4 23 113.4 105 73.5
64.8 31.2 Good 5 15 110.5 150 90.3 81.7 65.2 Very good 6 18 98.5
140 75.5 76.6 74.5 Very good 7 17 105.1 57 80.1 76.2 58.0 Very good
8 20 110.2 98 70.1 63.6 35.2 Good 9 19 102.5 89 88.0 85.9 80.6 Very
good 10 21 110.1 105 76.0 69.0 55.0 Good 11 13 122.1 121 115.2 94.3
108.3 Very good 12 7 128.5 133 121.0 94.2 110.5 Very good 13 10
110.5 98 92.1 83.3 89.6 Very good 14 9 116.8 97 105.3 90.2 84.9
Very good 15 12 101.6 105 83.6 82.3 70.4 Very good 16 13 106.0 95
83.5 78.8 71.3 Very good 17 12 106.7 93 88.5 82.9 75.5 Very good 18
17 101.7 98 64.5 63.4 28.5 Good 19 12 105.4 102 93.2 88.4 88.5 Very
good 20 15 102.3 145 78.1 76.3 35.1 Good 21 14 104.7 118 82.5 78.8
32.3 Good 22 16 102.1 101 80.7 79.0 62.1 Good Comparative 1 15
135.4 200 39.2 29.0 0.6 Poor examples 2 10 111.7 200 86.0 77.0
Incapable Poor measurement 3 44 105.8 103 8.0 7.6 Incapable Poor
measurement 4 34 109.1 98 56.9 52.2 21.1 Poor 5 16 97.5 95 10.5
10.8 Incapable Poor measurement 6 17 106.0 88 62.4 58.9 Incapable
Poor measurement 7 40 98.8 100 50.8 51.4 Incapable Poor measurement
8 29 106.3 115 57.4 54.0 18.3 Poor 9 27 95.4 140 38.3 40.1
Incapable Poor measurement 10 35 102.2 135 11.5 11.3 Incapable Poor
measurement 11 42 109.5 98 42.5 38.8 Incapable Poor measurement A:
Polylactic acid B: Terephthalic acid/adipic acid/1,4-butanediol
copolymer CD I: N,N'-di-2,6-diisopropylphenylcarbodiimide MEE:
SOMASIF MEE MTE: SOMASIF MTE PEP-36:
Bis(2,6-di-tert-butyl-4-methylphenyl)-pentaerythritol-di-phosphite
JPH3800: Hydrogenated bisphenol A.cndot.pentaerythritol phosphite
polymer AO-330:
1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benze-
ne XL-1:
2,2-oxamidebis-[ethyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate]
T-234:
2-(2H-benzotriazole-2-yl)-4-6-bis(1-methyl-1-phenylethyl)phenol
UV-1164:
2-[4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine-2-yl]-5-(octyloxy)p-
henol T-326:
2-(2'-hydroxy-3'-t-butyl-5'-methylphenyl)-5-chlorobenzotriazole
CHIMASSOR:
Poly[{6-(1,1,3,3-tetramethylbutyl)amino-1,3,5-triazine-2,4-diyl-
}{(2,2,6,6-tetramethyl-4-piperidyl)imino}hexamethylene
{(2,2,6,6-tetramethyl-4-piperidyl)imino}]
[0137] In each of the resin compositions of examples 1 to 22, the
retaining rate of the flexural strength of not less than 60% was
maintained, and the test pieces after moisture heat test had a
surface on which low-molecular weight substances or metal salts
were not deposited, and had superior appearance. Since each of the
resin compositions contained the layered silicate, the resin
composition had low oxygen permeability coefficient. Although the
resin composition contained the layered silicate, the resin
composition had a low YI value.
[0138] In examples 13 to 22, the same hydrolysis resistance effect
as that of the case using only the phosphite was obtained by using
the phosphite compound along with the other additive by the clear
comparison of examples 13 to 22 and systems using only the additive
other than the phosphite compound as shown in comparative examples
6 to 8, 11.
[0139] On the other hand, each of comparative examples had the
following problems. Since the resin compositions of comparative
examples 1, 2 did not contain the layered silicate, the resin
compositions had low gas barrier property. Since the resin
compositions of comparative examples 1,2 did not contain the
phosphite compound, the resin compositions had inferior hydrolysis
resistance. Since the resin composition of comparative example 3
had excellent gas barrier property, but contained neither the
carbodiimide compound nor the phosphite compound, the resin
composition had inferior color tone, and had insufficient
hydrolysis resistance and appearance. Since the resin composition
of comparative example 5 did not contain the carbodiimide compound,
the hydrolysis resistance of the resin composition did not reach an
aimed level. Since the resin compositions of comparative examples
4, 6 to 11 did not contain the phosphite compound, the resin
compositions had insufficient, hydrolysis resistance and
appearance, and the resin compositions other than that of
comparative example 6 had insufficient color tone.
* * * * *