U.S. patent application number 15/604016 was filed with the patent office on 2017-09-14 for resin composition.
This patent application is currently assigned to TEIJIN LIMITED. The applicant listed for this patent is TEIJIN LIMITED. Invention is credited to Masahiro IWAI, Shunsuke KANEMATSU, Yuhei ONO, Shinichiro SHOJI.
Application Number | 20170260361 15/604016 |
Document ID | / |
Family ID | 51624554 |
Filed Date | 2017-09-14 |
United States Patent
Application |
20170260361 |
Kind Code |
A1 |
SHOJI; Shinichiro ; et
al. |
September 14, 2017 |
RESIN COMPOSITION
Abstract
Provided are a resin composition controlled such that after
keeping under a severe environment as in high temperature hot water
or in hot water under chemically severe condition, such as an
acidic or basic condition, etc., for a fixed period of time, it is
quickly decomposed; and a structure thereof.
Inventors: |
SHOJI; Shinichiro;
(Yamaguchi, JP) ; IWAI; Masahiro; (Yamaguchi,
JP) ; KANEMATSU; Shunsuke; (Yamaguchi, JP) ;
ONO; Yuhei; (Yamaguchi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
TEIJIN LIMITED |
Osaka |
|
JP |
|
|
Assignee: |
TEIJIN LIMITED
Osaka
JP
|
Family ID: |
51624554 |
Appl. No.: |
15/604016 |
Filed: |
May 24, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14768811 |
Aug 19, 2015 |
|
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PCT/JP2014/059057 |
Mar 20, 2014 |
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15604016 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C08K 2201/014 20130101;
C08L 101/16 20130101; C08K 5/29 20130101; D01F 6/625 20130101; C08K
5/29 20130101; C08L 67/04 20130101 |
International
Class: |
C08K 5/29 20060101
C08K005/29; D01F 6/62 20060101 D01F006/62 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 25, 2013 |
JP |
2013-062429 |
Jun 6, 2013 |
JP |
2013-120034 |
Jan 24, 2014 |
JP |
2014-011440 |
Claims
1. A resin composition containing a resin mainly derived from
water-soluble monomers and having autocatalysis (component A) and a
hydrolysis regulator (component B), the resin composition
satisfying any one of the following A1 to A3: A1: In hot water at
an arbitrary temperature of 135.degree. C. to 160.degree. C., after
3 hours, not only a resin composition-derived acidic group
concentration is 30 equivalents/ton or less, but also a weight of a
water-insoluble matter of the resin composition is 50% or more, and
after 24 hours, the weight of the water-insoluble matter of the
resin composition is 50% or less; A2: In hot water at an arbitrary
temperature of 160.degree. C. to 180.degree. C., after 2 hour, not
only a resin composition-derived acidic group concentration is 30
equivalents/ton or less, but also a weight of a water-insoluble
matter of the resin composition is 50% or more, and after 24 hours,
the weight of the water-insoluble matter of the resin composition
is 50% or less; and A3: In hot water at an arbitrary temperature of
180.degree. C. to 220.degree. C., after 1 hour, not only a resin
composition-derived acidic group concentration is 30
equivalents/ton or less, but also a weight of a water-insoluble
matter of the resin composition is 50% or more, and after 24 hours,
the weight of the water-insoluble matter of the resin composition
is 50% or less; wherein the component B has water resistance at
120.degree. C. of 95% or more and reactivity with an acidic group
at 190.degree. C. of 50% or more; and wherein the component B is
bis(2,6-diisopropylphenyl)carbodiimide having a purity of 99.9% or
more, and the compounds represented by the following formulae (4)
and (5) are present in a total content of less than 0.1%:
##STR00019## wherein each of R.sub.8 to R.sub.11 is an aliphatic
group having 3 carbon atoms, and at least one of them is a propyl
group, with the other group or groups being an isopropyl group;
##STR00020## wherein each of R.sub.12 to R.sub.15 is an aliphatic
group having 3 carbon atoms, and at least one group of them is
substituted on a position other than the ortho position.
2. The resin composition according to claim 1, wherein in hot water
at an arbitrary temperature of 135.degree. C. to 220.degree. C.,
after 100 hours, the weight of the water-insoluble matter of the
resin composition is 10% or less.
3. The resin composition according to claim 1, wherein a heat
deformation temperature of the resin composition is 135.degree. C.
to 300.degree. C.
4. The resin composition according to claim 1, wherein the
component A is a polyester.
5. The resin composition according to claim 4, wherein a main chain
of the component A is composed mainly of a lactic acid unit
represented by the following formula (1): ##STR00021##
6. The resin composition according to claim 5, wherein the
component A contains a stereocomplex phase formed of poly(L-lactic
acid) and poly(D-lactic acid).
7. A molded article comprising the resin composition according to
claim 1.
8. A fiber comprising the resin composition according to claim
1.
9. A resin composition including an aliphatic polyester mainly
derived from water-soluble monomers (component C) and a hydrolysis
regulator having reactivity with an acidic group in a 15%
hydrochloric acid aqueous solution at 100.degree. C. of 30% or more
(component D), the resin composition satisfying any one of the
following J1 to J2: J1: In the 15% hydrochloric acid aqueous
solution at 100.degree. C., after 6 hours, a weight average
molecular weight retention rate of the resin composition is 50% or
more, and after 24 hours, a weight of a water-insoluble matter of
the resin composition is 50% or less; and J2: In the 15%
hydrochloric acid aqueous solution at 120.degree. C., after 1 hour,
a weight average molecular weight retention rate of the resin
composition is 50% or more, and after 24 hours, a weight of a
water-insoluble matter of the resin composition is 50% or less.
10. The resin composition according to claim 9, wherein after 72
hours, the weight of the water-insoluble matter of the resin
composition is 1% or less.
11. The resin composition according to claim 9, wherein a main
chain of the aliphatic polyester is composed mainly of a lactic
acid unit represented by the following formula (1):
##STR00022##
12. The resin composition according to claim 9, wherein the
hydrolysis regulator (component D) is at least one member selected
from a carbodiimide compound and an epoxy compound.
13. A molded article comprising the resin composition according to
claim 9.
14. The resin composition according to claim 10, wherein a main
chain of the component A is composed mainly of a lactic acid unit
represented by the following formula (1): ##STR00023##
15. The resin composition according to claim 12, wherein the
hydrolysis regulator (component D) comprises an epoxy compound.
16. The resin composition according to claim 15, wherein the epoxy
compound is selected from the group consisting of alicyclic epoxy
compounds, epoxidized vegetable oils obtained by epoxidizing a
vegetable oil, and epoxy compounds having a glycidyl group.
17. The resin composition according to claim 15, wherein the epoxy
compound is selected from the group consisting of bifunctional and
polyfunctional epoxy compounds.
18. The resin composition according to claim 15, wherein the epoxy
compound is selected from the group consisting of alicyclic epoxy
compounds and diglycidyl ether compounds.
19. The resin composition according to claim 15, wherein the epoxy
compound is selected from the group consisting of
3,4-epoxycyclohexenylmethyl-3',4'-epoxycyclohexene carboxylate,
.epsilon.-caprolactone-modified
3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexane carboxylate,
epoxidized 3-cyclohexene-1,2-dicarboxylic acid
bis(3-cyclohexenylmethyl)-modified .epsilon.-caprolactone, and
epoxidized butanetetracarboxylic acid
tetrakis-(3-cyclohexenylmethyl)-modified .epsilon.-caprolactone.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This is a continuation of application Ser. No. 14/768,811
filed Aug. 19, 2015, which is a National Stage of International
Application No. PCT/JP2014/059057 filed Mar. 20, 2014 (claiming
priority based on Japanese Patent Application No. 2013-062429 filed
Mar. 25, 2013, Japanese Patent Application No. 2013-120034 filed
Jun. 6, 2013, and Japanese Patent Application No. 2014-011440 filed
Jan. 24, 2014), the contents of which are incorporated herein by
reference in their entirety.
TECHNICAL FIELD
[0002] The present invention relates to a resin composition
containing a resin containing, as a main component, a water-soluble
monomer and having autocatalysis (component A) and a hydrolysis
regulator (component B).
BACKGROUND ART
[0003] In recent years, from the purpose of global environmental
protection, resins which are easily decomposed under the natural
environment are watched and studied in the world. As the resins
which are easily decomposed under the natural environment,
biodegradable polymers represented by aliphatic polyesters, such as
polylactic acid, polyglycolic acid, poly(3-hydroxybutyrate),
polycaprolactone, etc., are known.
[0004] Above all, polylactic acid is a polymer material that is
high in biological safety and environmentally friendly because it
is made of, as a raw material, from lactic acid obtained from a
plant-derived raw material, or a derivative thereof. For that
reason, utilization as a general-purpose polymer is investigated,
and utilization as films, fibers, injection molded articles, and
the like is investigated.
[0005] Recently, paying attention to easy decomposability of those
resins and water solubility of decomposed monomers, practical use
for excavation technology in the oil field is investigated (Patent
Literatures 1 to 3). In this application, it is required that after
keeping the weight and shape of a resin in hot water for a fixed
period of time, the resin is quickly decomposed (see FIG. 1).
However, in general, since aliphatic polyesters and the like are
inferior in hydrolysis resistance, though they are usable up to a
medium temperature of about 120.degree. C., there is involved such
a problem that they are immediately decomposed in high-temperature
hot water (see FIG. 2), so that a desired performance cannot be
exhibited.
[0006] Slowly decomposable resins, such as aromatic polyesters,
etc., are not quickly decomposed even in hot water (see FIG. 3),
and furthermore, there is involved such a problem that monomers
generated by decomposition react with other components of the
foregoing application and are deposited in water (Patent Literature
4). With respect to the high temperature, there are various
definitions, such as "127.degree. C. to 193.degree. C." described
in the report: U.S. Shale Gas, published in 2008 by Halliburton
Company, "149.degree. C. or higher" described in Oil and Gas
Review, 2002.5, published by Japan Oil, Gas and Metals National
Corporation, etc., and in general, the high temperature is
considered to be higher than "125.degree. C. to 150.degree. C.".
Incidentally, in the present invention, a temperature higher than
135.degree. C. is referred to as "high temperature".
[0007] Meanwhile, in order to enhance the hydrolysis resistance of
aliphatic polyesters and the like, there is already proposed a
method in which a hydrolysis regulator, such as a carbodiimide
compound, etc., is used, and an acidic group generated at the early
stage and by decomposition in the resin is sealed, thereby
inhibiting the hydrolysis (Patent Literatures 4 to 6).
[0008] The acidic group generated by hydrolysis of the aliphatic
polyester, such as a carboxyl group, etc., becomes an autocatalyst
to promote the hydrolysis, and therefore, it is confirmed that by
immediately sealing this by a carbodiimide compound or the like,
the hydrolysis resistance under the moist heat environment at about
50 to 120.degree. C. is enhanced.
[0009] However, with respect to the hydrolysis inhibition in hot
water at a higher temperature than 135.degree. C., there are not
made sufficient investigations from the viewpoints of resin or
hydrolysis regulator.
[0010] In the light of the above, it is the actual situation that a
resin composition exhibiting a desired performance as shown in FIG.
1 in hot water at a higher temperature than 135.degree. C. has not
been obtained yet in the excavation technology in the oil
field.
[0011] In addition, in the application of the excavation technology
in the oil field, it is required that after keeping the weight and
shape of a resin in hot water under a chemically severe condition,
such as an acidic or basic condition, etc., for a fixed period of
time, the resin is quickly decomposed (see FIG. 5). However, in
general, since aliphatic polyesters and the like are inferior in
hydrolysis resistance, though they are usable in approximately
neutral hot water, they are quickly decomposed in strongly acidic
or basic hot water (see FIG. 6), so that there is involved such a
problem that a desired performance cannot be exhibited.
[0012] In addition, slowly decomposable resins, such as aromatic
polyesters, etc., are not quickly decomposed even in strongly
acidic or basic hot water (see FIG. 3), and furthermore, there is
involved such a problem that monomers generated by decomposition
react with other components of the foregoing application and are
deposited in water.
CITATION LIST
Patent Literature
[0013] Patent Literature 1: JP-A-2009-114448
[0014] Patent Literature 2: U.S. Pat. No. 7,267,170
[0015] Patent Literature 3: U.S. Pat. No. 7,228,904
[0016] Patent Literature 4: U.S. Pat. No. 7,275,596
[0017] Patent Literature 5: JP-A-2012-012560
[0018] Patent Literature 6: JP-A-2009-173582
[0019] Patent Literature 7: JP-A-2002-30208
SUMMARY OF INVENTION
Technical Problem
[0020] An object of a first invention of the present application is
to solve the above-described problems of the background art and to
provide a resin composition which is quickly decomposed after
keeping the weight and shape of the resin in hot water at a higher
temperature than 135.degree. C. for a fixed period of time.
[0021] In addition, an object of a second invention of the present
application is to provide a resin composition which is quickly
decomposed after keeping the weight and shape of the resin in hot
water under a chemically severe condition, such as an acidic or
basic condition, etc., for a fixed period of time.
Solution to Problem
[0022] The present inventors made extensive and intensive
investigations regarding a resin composition which is quickly
decomposed after keeping the weight and shape of the resin in hot
water at a higher temperature than 135.degree. C. for a fixed
period of time.
[0023] As a result, it has been found that in the case where a
concentration of an acidic group can be kept low by using a resin
containing, as a main component, a water-soluble monomer and having
autocatalysis, hydrolysis is inhibited during that time, and a
decrease of the molecular weight becomes gentle, so that the weight
and shape are kept, and at a point of time when a concentration of
the acidic group cannot be kept low, decomposition of the resin is
rapidly promoted (see FIG. 4).
[0024] As a result of making further investigations, it has been
found that when a hydrolysis regulator in which not only water
resistance at 120.degree. C. is 95% or more, but also reactivity
with an acidic group at 190.degree. C. is 50% or more is used for
sealing the acidic group, a concentration of the acidic group can
be efficiently kept low in hot water at a higher temperature than
135.degree. C., and a timing of rapid decomposition of the resin
can be controlled according to its addition amount.
[0025] That is, it has been found that when a resin containing, as
a main component, a water-soluble monomer and having autocatalysis
and a hydrolysis regulator in which not only water resistance at
120.degree. C. is 95% or more, but also reactivity with an acidic
group at 190.degree. C. is 50% or more are compounded, the
resultant is quickly decomposed after keeping the weight and shape
of the resin in hot water at a higher temperature than 135.degree.
C. for a fixed period of time, leading to accomplishment of the
present invention.
[0026] Specifically, according to the present invention, the
following resin composition is provided.
(1) A resin composition containing a resin containing, as a main
component, a water-soluble monomer and having autocatalysis
(component A) and a hydrolysis regulator (component B), the resin
composition satisfying any one of the following A1 to A3: A1: In
hot water at an arbitrary temperature of 135.degree. C. to
160.degree. C., after 3 hours, not only a resin composition-derived
acidic group concentration is 30 equivalents/ton or less, but also
a weight of a water-insoluble matter of the resin composition is
50% or more, and after 24 hours, the weight of the water-insoluble
matter of the resin composition is 50% or less; A2: In hot water at
an arbitrary temperature of 160.degree. C. to 180.degree. C.,
after, 1 hour, not only a resin composition-derived acidic group
concentration is 30 equivalents/ton or less, but also a weight of a
water-insoluble matter of the resin composition is 50% or more, and
after 24 hours, the weight of the water-insoluble matter of the
resin composition is 50% or less; and A3: In hot water at an
arbitrary temperature of 180.degree. C. to 220.degree. C., after 1
hour, not only a resin composition-derived acidic group
concentration is 30 equivalents/ton or less, but also a weight of a
water-insoluble matter of the resin composition is 50% or more, and
after 24 hours, the weight of the water-insoluble matter of the
resin composition is 50% or less.
[0027] The following are also included in the present
invention.
(2) The resin composition as set forth above in (1), wherein the
component B has water resistance at 120.degree. C. of 95% or more
and reactivity with an acidic group at 190.degree. C. of 50% or
more. (3) The resin composition as set forth above in (1) or (2),
wherein in hot water at an arbitrary temperature of 135.degree. C.
to 220.degree. C., after 100 hours, the weight of the
water-insoluble matter of the resin composition is 10% or less. (4)
The resin composition as set forth above in any one of (1) to (3),
wherein a heat deformation temperature of the resin composition is
135.degree. C. to 300.degree. C. (5) The resin composition as set
forth above in any one of (1) to (4), wherein the component A is a
polyester. (6) The resin composition as set forth above in (5),
wherein a main chain of the component A is composed mainly of a
lactic acid unit represented by the following formula (1):
##STR00001##
(7) The resin composition as set forth above in (6), wherein the
component A contains a stereocomplex phase formed of poly(L-lactic
acid) and poly(D-lactic acid). (8) The resin composition as set
forth above in any one of (1) to (7), wherein the component B is a
carbodiimide compound. (9) The resin composition as set forth above
in (8), wherein the component B is a carbodiimide compound
represented by the following formula (2):
##STR00002##
(In the formula, each of R.sub.1 to R.sub.4 is independently an
aliphatic group having 1 to 20 carbon atoms, an alicyclic group
having 3 to 20 carbon atoms, an aromatic group having 5 to 15
carbon atoms, or a combination thereof, and may contain a hetero
atom; each of X and Y is independently a hydrogen atom, an
aliphatic group having 1 to 20 carbon atoms, an alicyclic group
having 3 to 20 carbon atoms, an aromatic group having 5 to 15
carbon atoms, or a combination thereof, and may contain a hetero
atom; and the respective aromatic rings may be bonded to each other
via a substituent to form a cyclic structure.) (10) The resin
composition as set forth above in (9), wherein the component B is
bis(2,6-diisopropylphenyl) carbodiimide (11) The resin composition
as set forth above in (8), wherein the component B is a
carbodiimide compound composed of a repeating unit represented by
the following formula (3):
##STR00003##
(In the formula, each of R.sub.5 to R.sub.7 is independently an
aliphatic group having 1 to 20 carbon atoms, an alicyclic group
having 3 to 20 carbon atoms, an aromatic group having 5 to 15
carbon atoms, or a combination thereof, and may contain a hetero
atom.) (12) A molded article comprising the resin composition as
set forth above in any one of (1) to (11). (13) A fiber comprising
the resin composition as set forth above in any one of (1) to
(11).
[0028] In addition, the present inventors also made extensive and
intensive investigations regarding a resin composition which is
quickly decomposed after keeping the weight and shape of the resin
in hot water under a chemically severe condition, such as an acidic
or basic condition, etc., for a fixed period of time.
[0029] As a result, it has been found that in the case where a
concentration of an acidic group in a polymer can be kept low by
using an aliphatic polyester containing, as a main component, a
water-soluble monomer, hydrolysis is inhibited during that time,
and a decrease of the molecular weight becomes gentle, so that the
weight and shape of a resin are kept to some extent during that
time, and at a point of time when a concentration of the acidic
group in the polymer cannot be kept low, decomposition of the resin
is rapidly promoted (see FIG. 8).
[0030] As a result of making further investigations, it has been
found that when a hydrolysis regulator satisfying specified
requirements is used for sealing the acidic group, a concentration
of the acidic group can be efficiently kept low in hot water under
a chemically severe condition, such as an acidic or basic
condition, etc., and a timing of rapid decomposition of the resin
can be controlled according to its addition amount.
[0031] Then, it has been found that when an aliphatic polyester
containing, as a main component, a water-soluble monomer is
compounded with a hydrolysis regulator whose reactivity with the
acidic group satisfies specified requirements, the resultant is
quickly decomposed after keeping the weight and shape of a resin in
hot water under a chemically severe condition, such as an acidic or
basic condition, etc., for a fixed period of time, leading to
accomplishment of a second invention of the present
application.
[0032] Specifically, according to the second invention of the
present application, the following resin composition is
provided.
(14) A resin composition including an aliphatic polyester
containing, as a main component, a water-soluble monomer (component
C) and a hydrolysis regulator having reactivity with an acidic
group in a 15% hydrochloric acid aqueous solution at 100.degree. C.
of 30% or more (component D), the resin composition satisfying any
one of the following J1 to J2: J1: In the 15% hydrochloric acid
aqueous solution at 100.degree. C., after 6 hours, a weight average
molecular weight retention rate of the resin composition is 50% or
more, and after 24 hours, a weight of a water-insoluble matter of
the resin composition is 50% or less; and J2: In the 15%
hydrochloric acid aqueous solution at 120.degree. C., after 1 hour,
a weight average molecular weight retention rate of the resin
composition is 50% or more, and after 24 hours, a weight of a
water-insoluble matter of the resin composition is 50% or less.
[0033] In addition, the following are also included in the second
invention of the present application.
(15) The resin composition as set forth above in (14), wherein
after 72 hours, the weight of the water-insoluble matter of the
resin composition is 1% or less. (16) The resin composition as set
forth above in (14) or (15), wherein a main chain of the component
A is composed mainly of a lactic acid unit represented by the
following formula (1):
##STR00004##
(17) The resin composition as set forth above in any one of (14) to
(16), wherein the hydrolysis regulator (component D) is at least
one member selected from a carbodiimide compound and an epoxy
compound. (18) A molded article comprising the resin composition as
set forth above in any one of (14) to (16).
Advantageous Effects of Invention
[0034] The resin composition of the first invention of the present
invention can be quickly decomposed after keeping the weight and
shape of the resin in hot water at a higher temperature than
135.degree. C. for a fixed period of time.
[0035] Furthermore, since the resin containing, as a main
component, a water-soluble monomer and having autocatalysis is
used, the resin composition is efficiently dissolved in
high-temperature hot water after decomposition, and it is possible
to significantly reduce deposition or the like to be caused due to
a reaction with other component, which is considered to be
problematic in a part of aromatic polyesters. By using the
hydrolysis regulator in which not only water resistance at
120.degree. C. is 95% or more, but also reactivity with an acidic
group at 190.degree. C. is 50% or more in order to seal the acidic
group, steady decomposition inhibition can be achieved, and a
timing of decomposition of the resin in high-temperature hot water
can be controlled according to its addition amount.
[0036] For that reason, the resin composition of the present
invention exhibits a desired performance in the excavation
technology in the oil field and can be suitably used as resin
molded articles of this application, especially fibers.
[0037] The resin composition of the second invention of the present
application can be quickly decomposed after keeping the weight and
shape of the resin in hot water under a chemically severe
condition, such as an acidic or basic condition, etc., for a fixed
period of time.
[0038] Furthermore, since the aliphatic polyester containing, as a
main component, a water-soluble monomer is used, the resin
composition is efficiently dissolved in water after decomposition,
and it is possible to significantly reduce deposition or the like
to be caused due to a reaction with other component, which is
considered to be problematic in a part of aromatic polyesters. By
using the hydrolysis regulator satisfying the requirement specified
in the present application in order to seal the acidic group, the
hydrolysis regulator continues to exhibit a decomposition
inhibition performance at a fixed level so long as it exists in the
resin composition, and therefore, a timing of decomposition of the
resin in high-temperature hot water can be controlled according to
the addition amount of the hydrolysis regulator.
[0039] For that reason, the resin composition of the present
invention exhibits a desired performance in the excavation
technology in the oil field and can be suitably used as resin
molded articles of this application.
BRIEF DESCRIPTION OF DRAWINGS
[0040] FIG. 1 is an image view in which in the case of using a
resin in hot water at a higher temperature than 135.degree. C., the
resin is quickly decomposed after keeping the weight and shape of
the resin for a fixed period of time and shows a behavior which is
achieved in the resin composition of the first invention of the
present application.
[0041] FIG. 2 is an image view in which in the case of using a
resin in hot water at a higher temperature than 135.degree. C.,
decomposition is rapidly advanced from the early stage and is
concerned with a behavior in a general aliphatic polyester.
[0042] FIG. 3 is an image view in which in the case of using a
resin in hot water at a higher temperature than 135.degree. C.,
decomposition is rapidly advanced from the early stage and is
concerned with a behavior in a general aromatic polyester.
[0043] FIG. 4 is an image view in which in the case of using a
resin in hot water at a higher temperature than 135.degree. C.,
changes in a molecular weight (m) and an acidic group amount (g)
necessary for achieving a behavior of a change of a weight (w) of
the resin as in FIG. 1 are expressed and is concerned with a
behavior which is achieved in the resin composition of the first
invention of the present application.
[0044] FIG. 5 is an image view in which in the case of using a
resin in hot water under a chemically severe condition, such as an
acidic or basic condition, etc., the resin is quickly decomposed
after keeping the weight and shape of the resin for a fixed period
of time and is concerned with a behavior which is achieved in the
resin composition of the second invention of the present
application.
[0045] FIG. 6 is an image view in which in the case of using a
resin in hot water under a chemically severe condition, such as an
acidic or basic condition, etc., decomposition is rapidly advanced
from the early stage and is concerned with a behavior in a general
aliphatic polyester.
[0046] FIG. 7 is an image view in which in the case of using a
resin in hot water under a chemically severe condition, such as an
acidic or basic condition, etc., decomposition is rapidly advanced
from the early stage and is concerned with a behavior in a general
aromatic polyester.
[0047] FIG. 8 is an image view in which in the case of using a
resin in hot water under a chemically severe condition, such as an
acidic or basic condition, etc., changes in a molecular weight (m)
and an acidic group amount (g) necessary for achieving a behavior
of a change of a weight (w) of the resin as in FIG. 5 are expressed
and is concerned with a behavior which is achieved in the resin
composition of the second invention of the present application.
DESCRIPTION OF EMBODIMENTS
[0048] The first invention of the present application is hereunder
explained in detail.
1. A resin composition containing a resin containing, as a main
component, a water-soluble monomer and having autocatalysis
(component A) and a hydrolysis regulator (component B), the resin
composition satisfying any one of the following A1 to A3: A1: In
hot water at an arbitrary temperature of 135.degree. C. to
160.degree. C., after 3 hours, not only a resin composition-derived
acidic group concentration is 30 equivalents/ton or less, but also
a weight of a water-insoluble matter of the resin composition is
50% or more, and after 24 hours, the weight of the water-insoluble
matter of the resin composition is 50% or less; A2: In hot water at
an arbitrary temperature of 160.degree. C. to 180.degree. C., after
2 hour, not only a resin composition-derived acidic group
concentration is 30 equivalents/ton or less, but also a weight of a
water-insoluble matter of the resin composition is 50% or more, and
after 24 hours, the weight of the water-insoluble matter of the
resin composition is 50% or less; and A3: In hot water at an
arbitrary temperature of 180.degree. C. to 220.degree. C., after 1
hour, not only a resin composition-derived acidic group
concentration is 30 equivalents/ton or less, but also a weight of a
water-insoluble matter of the resin composition is 50% or more, and
after 24 hours, the weight of the water-insoluble matter of the
resin composition is 50% or less.
<Resin Containing, as a Main Component, a Water-Soluble Monomer
and Having Autocatalysis (Component A)>
[0049] In the present invention, in the resin containing, as a main
component, a water-soluble monomer and having autocatalysis
(component A), the monomer generated by decomposition exhibits
solubility in water, and the resin in which an acidic group
generated by decomposition has autocatalysis, or at least apart of
ends of the resin is sealed by the component B.
[0050] The term "water-soluble" referred to herein means that the
solubility in water at 25.degree. C. is 0.1 g/L or more. From the
viewpoint that the resin composition to be used does not remain in
water after decomposition, the solubility in water of the
water-soluble monomer is preferably 1 g/L or more, more preferably
3 g/L or more, and still more preferably 5 g/L, or more.
[0051] The "main component" means that it occupies 90 mol % or more
of the constituent components. A proportion of the main component
is preferably 95 to 100 mol %, and more preferably 98 to 100 mol
%.
[0052] As the component A, at least one member selected from the
group consisting of polyesters, polyamides, polyamide-imides,
polyimides, polyurethanes, and polyester amides is exemplified.
Preferably, polyesters are exemplified.
[0053] Examples of the polyester include polymers or copolymers
obtained by polycondensing at least one member selected from a
dicarboxylic acid or an ester forming derivative thereof, a diol or
an ester forming derivative thereof, a hydroxycarboxylic acid or an
ester forming derivative thereof, and a lactone. Preferably,
polyesters composed of a hydroxycarboxylic acid or an ester forming
derivative thereof are exemplified. More preferably, aliphatic
polyesters composed of a hydroxycarboxylic acid or an ester forming
derivative thereof are exemplified.
[0054] Such a thermoplastic polyester may contain a crosslinking
structure generated by being treated with a radical generating
source, for example, an energy active ray, an oxidizing agent,
etc., from the standpoint of moldability or the like.
[0055] Examples of the dicarboxylic acid or its ester forming
derivative include aromatic dicarboxylic acids, such as
terephthalic acid, isophthalic acid, phthalic acid,
2,6-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid,
bis(p-carboxyphenyl)methane, anthracenedicarboxylic acid,
4,4'-diphenyl ether dicarboxylic acid, 5-tetrabutylphosphonium
isophthalic acid, 5-sodiumsulfoisophthalic acid, etc. Aliphatic
dicarboxylic acids, such as oxalic acid, succinic acid, adipic
acid, sebacic acid, azelaic acid, dodecanedioic acid, malonic acid,
glutaric acid, dimer acid, etc., are also exemplified. Alicyclic
dicarboxylic acids, such as 1, 3-cyclohexanedicarboxylic acid,
1,4-cyclohexanedicarboxylic acid, etc., are also exemplified. Ester
forming derivatives thereof are also exemplified.
[0056] Examples of the diol or its ester forming derivative include
aliphatic glycols having 2 to 20 carbon atoms, namely ethylene
glycol, 1,3-propanediol, propylene glycol, 1,4-butanediol,
neopentyl glycol, 1,5-pentandiol, 1,6-hexanediol, decamethylene
glycol, cyclohexanedimethanol, cyclohexanediol, dimer diol,
etc.
[0057] Long-chain glycols having a molecular weight of 200 to
100,000, namely polyethylene glycol, poly(1,3-propylene glycol),
poly(1,2-propylene glycol), polytetramethylene glycol, etc., are
also exemplified. Aromatic dioxy compounds, namely
4,4'-dihydroxybiphenyl, hydroquinone, tert-butylhydroquinone,
bisphenol A, bisphenol S, bisphenol F, etc., are also exemplified.
Ester forming derivatives thereof are also exemplified.
[0058] Examples of the hydroxycarboxylic acid include glycolic
acid, lactic acid, hydroxypropionic acid, hydroxybutyric acid,
hydroxyvaleric acid, hydroxycaproic acid, hydroxybenzoic acid,
p-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid, and ester
forming derivatives thereof, and the like. Examples of the lactone
include caprolactone, valerolactone, propiolactone, undecalactone,
1,5-oxepan-2-one, and the like.
[0059] Examples of the aliphatic polyester include polymers
containing an aliphatic hydroxycarboxylic acid as a main
constituent component, polymers obtained by polycondensing an
aliphatic multivalent carboxylic acid or an ester forming
derivative thereof and an aliphatic polyhydric alcohol as main
constituent components, and copolymers thereof.
[0060] Examples of the polymer containing an aliphatic
hydroxycarboxylic acid as a main constituent component may include
polycondensates of glycolic acid, lactic acid, hydroxypropionic
acid, hydroxybutyric acid, hydroxyvaleric acid, hydroxycaproic
acid, or the like, and copolymers thereof. Above all, polyglycolic
acid, polylactic acid, poly(3-hydroxycarbonbutyric acid),
poly(4-polyhydroxybutyric acid), poly(3-hydroxyhexanoic acid),
polycaprolactone, and copolymers thereof, and the like are
exemplified. In particular, poly(L-lactic acid), poly(D-lactic
acid), stereocomplex polylactic acid, and racemic polylactic acid
are exemplified.
[0061] Polymers containing an aliphatic multivalent carboxylic acid
and an aliphatic polyhydric alcohol as main constituent components
are exemplified. Examples of the multivalent carboxylic acid
include aliphatic dicarboxylic acids, such as oxalic acid, succinic
acid, adipic acid, sebacic acid, azelaic acid, dodecanedioic acid,
malonic acid, glutaric acid, dimer acid, etc.; alicyclic
dicarboxylic acid units, such as 1,3-cyclohexanedicarboxylic acid,
1,4-cyclohexanedicarboxylic acid, etc.; and ester forming
derivatives thereof. Examples of the diol component include
aliphatic glycols having 2 to 20 carbon atoms, such as ethylene
glycol, 1,3-propanediol, propylene glycol, 1,4-butanediol,
neopentyl glycol, 1,5-pentanediol, 1,6-hexanediol, decamethylene
glycol, cyclohexanedimethanol, cyclohexanediol, dimer diol, etc.
Long-chain glycols having a molecular weight of 200 to 100,000,
namely polyethylene glycol, poly(1,3-proylene glycol),
poly(1,2-propylene glycol), and polytetramethylene glycol are
exemplified. Specifically, polyethylene adipate, polyethylene
succinate, polybutylene adipate, polybutylene succinate, and
copolymers thereof, and the like are exemplified.
[0062] The polyester can be produced by well-known methods (for
example, methods described in Saturated Polyester Resin Handbook
(written by Kazuo Yuki, Nikkan Kogyo Shimbun Ltd. (published on
Dec. 22, 1989)).
[0063] Furthermore, examples of the polyester include, in addition
to the above-described polyesters, unsaturated polyester resins
obtained by copolymerizing an unsaturated multivalent carboxylic
acid or an ester forming derivative; and polyester elastomers
containing a low melting-point polymer segment.
[0064] Examples of the unsaturated multivalent carboxylic acid
include maleic anhydride, tetrahydromaleic anhydride, fumaric acid,
endomethylene tetrahydromaleic anhydride, and the like. In such an
unsaturated polyester, for the purpose of controlling its curing
properties, various monomers are added, and the unsaturated
polyester is cured by means of thermal curing, radical curing, or
curing with an active energy ray, such as light, electron beams,
etc., and then molded.
[0065] Furthermore, in the present invention, the polyester may
also be a polyester elastomer obtained by copolymerizing a soft
component. The polyester elastomer is a block copolymer composed of
a high melting-point polyester segment and a low melting-point
polymer segment having a molecular weight of 400 to 6,000 as
described in publicly known literatures, for example,
JP-A-11-92636, or the like. In the case of forming a polymer by
using only a high melting-point polyester segment, its melting
point is 150.degree. C. or higher, and such a polymer can be
suitably used.
[0066] The polyester is preferably a polyester composed of a
hydroxycarboxylic acid or an ester forming derivative thereof. An
aliphatic polyester composed of a hydroxycarboxylic acid or an
ester forming derivative thereof is more preferred. Furthermore, it
is especially preferred that the aliphatic polyester is
poly(L-lactic acid), poly(D-lactic acid), or stereocomplex
polylactic acid.
[0067] Here, as for the polylactic acid, its main chain is composed
of a lactic acid unit represented by the following formula (1). In
this specification, the term "mainly" means that a proportion of
the unit is preferably 90 to 100 mol %, more preferably 95 to 100
mol %, and still more preferably 98 to 100 mol %.
##STR00005##
[0068] The lactic acid unit represented by the formula (1) includes
an L-lactic acid unit and a D-lactic acid unit, which are an
optical isomer to each other. It is preferred that a main chain of
the polylactic acid is mainly an L-lactic acid unit, a D-lactic
acid unit, or a combination thereof.
[0069] The polylactic acid is preferably poly(D-lactic acid) in
which a main chain thereof is composed mainly of a D-lactic acid
unit, or poly(L-lactic acid) in which a main chain thereof is
composed mainly of an L-lactic acid unit. A proportion of other
unit constituting the main chain is in the range of preferably 0 to
10 mol %, more preferably 0 to 5 mol %, and still more preferably 0
to 2 mol %.
[0070] Examples of the other unit constituting the main chain
include units derived from a dicarboxylic acid, a polyhydric
alcohol, a hydroxycarboxylic acid, a lactone, or the like.
[0071] Examples of the dicarboxylic acid include succinic acid,
adipic acid, azelaic acid, sebacic acid, terephthalic acid,
isophthalic acid, and the like. Examples of the polyhydric alcohol
include aliphatic polyhydric alcohols, such as ethylene glycol,
propylene glycol, butanediol, pentanediol, hexanediol, octanediol,
glycerin, sorbitan, neopentyl glycol, diethylene glycol,
triethylene glycol, polyethylene glycol, polypropylene glycol,
etc.; aromatic polyhydric alcohols, such as bisphenol having
ethylene oxide added thereto, etc.; and the like. Examples of the
hydroxycarboxylic acid include glycolic acid, hydroxybutyric acid,
and the like. Examples of the lactone include glycolide,
.epsilon.-caprolactone. .beta.-propiolactone,
.delta.-butyrolactone, .beta.- or .gamma.-butyrolactone,
pivalolactone, .delta.-valerolactone, and the like.
[0072] For the purpose of making both mechanical physical
properties of a molded article and moldability compatible with each
other, a weight average molecular weight of the polylactic acid is
in the range of preferably 50,000 to 500,000, more preferably
80,000 to 350,000, and still more preferably 120,000 to 250,000.
The weight average molecular weight is a value obtained by
measurement by means of gel permeation chromatography (GPC) and
conversion into standard polystyrene.
[0073] When the polylactic acid (component A) is poly(D-lactic
acid) or poly(L-lactic acid) and is a homo-phase polylactic acid,
it is preferred that when measured by a differential scanning
calorimeter (DSC), the polylactic acid has a crystal melting peak
(Tmh) at between 150 to 190.degree. C. and a crystal melting heat
(.DELTA.Hmsc) of 10 J/g or more. When the foregoing ranges of the
crystal melting point and crystal melting heat are satisfied, the
heat resistance can be increased.
[0074] The main chain of the polylactic acid is preferably
stereocomplex polylactic acid containing a stereocomplex phase
formed of a poly(L-lactic acid) unit and a poly(D-lactic acid)
unit. It is preferred that when measured by a differential scanning
calorimeter (DSC), the stereocomplex polylactic acid exhibits a
crystal melting peak of 190.degree. C. or higher.
[0075] In the stereocomplex polylactic acid, a stereocomplex
crystallization degree (S) as prescribed by the following equation
(i) is preferably 90 to 100%.
S=[.DELTA.Hms/(.DELTA.Hmh+.DELTA.Hms)].times.100 (i)
[0076] (Here, .DELTA.Hms represents a melting enthalpy of the
stereocomplex-phase polylactic acid crystal, and .DELTA.Hmh
represents a melting enthalpy of the polylactic acid homo-phase
crystal.)
[0077] The crystallization degree of the stereocomplex polylactic
acid, particularly the crystallization degree by the XRD
measurement is in the range of preferably at least 5%, more
preferably 5 to 60%, still more preferably 7 to 60%, and especially
preferably 10 to 60%.
[0078] The crystal melting point of the stereocomplex polylactic
acid is in the range of preferably 190 to 250.degree. C., and more
preferably 200 to 230.degree. C. The crystal melting enthalpy of
the stereocomplex polylactic acid by the DSC measurement is in the
range of preferably 20 J/g or more, more preferably 20 to 80 J/g,
and still more preferably 30 to 80 J/g. When the crystal melting
point of the stereocomplex polylactic acid is lower than
190.degree. C., the heat resistance is worsened. When it is higher
than 250.degree. C., molding at a high temperature of 250.degree.
C. or higher is needed, so that there may be the case where it is
difficult to inhibit the heat decomposition of the resin. In
consequence, it is preferred that when measured by a differential
scanning calorimeter (DSC), the resin composition of the present
invention exhibits a crystal melting peak of 190.degree. C. or
higher.
[0079] In the stereocomplex polylactic acid, a weight ratio of
poly(D-lactic acid) to poly(L-lactic acid) is in the range of
preferably 90/10 to 10/90, more preferably 80/20 to 20/80, still
more preferably 30/70 to 70/30, and especially preferably 40/60 to
60/40. Theoretically, it is preferred that the weight ratio is
close to 1/1 as far as possible.
[0080] A weight average molecular weight of the stereocomplex
polylactic acid is in the range of preferably 50,000 to 500,000,
more preferably 80,000 to 350,000, and still more preferably
120,000 to 250,000. The weight average molecular weight is a value
obtained by measurement by means of gel permeation chromatography
(GPC) and conversion into standard polystyrene.
[0081] The poly(L-lactic acid) and poly(D-lactic acid) can be
produced by a conventionally known method. For example, the
poly(L-lactic acid) and poly(D-lactic acid) can be produced by
subjecting L-lactide or D-lactide to ring-opening polymerization,
respectively in the presence of a metal-containing catalyst. The
poly(L-lactic acid) and poly(D-lactic acid) can also be produced by
subjecting a low-molecular weight polylactic acid containing a
metal-containing catalyst, after being optionally crystallized or
without being crystallized, to solid-phase polymerization under
reduced pressure or by pressurization from atmospheric pressure in
the presence or absence of an inert gas stream. Furthermore, the
poly(L-lactic acid) and poly(D-lactic acid) can be produced by a
direct polymerization method of subjecting lactic acid to
dehydration condensation in the presence or absence of an organic
solvent.
[0082] The polymerization reaction can be carried out in a
conventionally known reaction vessel, and for example, in the
ring-opening polymerization or direct polymerization method, a
vertical reactor or horizontal reactor equipped with a high
viscosity stirring blade, such as a helical ribbon blade, etc., can
be used alone or in parallel. All of a batch type, a continuous
type, and a semi-batch type may be used, or these may be
combined.
[0083] An alcohol may be used as a polymerization initiator. It is
preferred that such an alcohol does not hinder the polymerization
of polylactic acid and is nonvolatile, and for example, decanol,
dodecanol, tetradecanol, hexadecanol, octadecanol, ethylene glycol,
trimethylolpropane, pentaerythritol, or the like can be suitably
used. It may be said that an embodiment in which the polylactic
acid prepolymer used in the solid-phase polymerization method is
previously crystallized is preferred from the standpoint of
preventing the fusion of resin pellets. The prepolymer is
polymerized in a state of solid at a temperature in the range of a
glass transition temperature of the prepolymer or higher and lower
than a melting point thereof in a fixed vertical reaction vessel or
horizontal reaction vessel, or a reaction vessel (rotary kiln,
etc.) in which the vessel itself rotates, such as a tumbler or a
kiln.
[0084] Examples of the metal-containing catalyst include fatty acid
salts, carbonates, sulfates, phosphates, oxides, hydroxides,
halides, alcoholates, and like of an alkali metal, an alkaline
earth metal, a rare-earth element, a transition metal, aluminum,
germanium, tin, antimony, titanium, etc. Above all, fatty acid
salts, carbonates, sulfates, phosphates, oxides, hydroxides,
halides, and alcoholates containing at least one metal selected
from tin, aluminum, zinc, calcium, titanium, germanium, manganese,
magnesium, and a rare-earth element are preferred.
[0085] Specifically, from the standpoints of catalytic activity and
less occurrence of a side reaction, tin-containing compounds, such
as stannous chloride, stannous bromide, stannous iodide, stannous
sulfate, stannic oxide, tin myristate, tin octylate, tin stearate,
tetraphenyltin, etc., are exemplified as a preferred catalyst.
Above all, tin(II) compounds, specifically diethoxytin,
dinonyloxytin, tin(II) myristate, tin(II) octylate, tin(II)
stearate, tin(II) chloride, and the like, are suitably
exemplified.
[0086] A use amount of the catalyst is 0.42.times.10.sup.-4 to
100.times.10.sup.-4 (mol) per kg of the lactide, and furthermore,
taking into consideration the reactivity, the color tone of the
obtained polylactide, and the stability, the catalyst is used in an
amount of preferably 1.68.times.10.sup.-4 to 42.1.times.10.sup.-4
(mol), and especially preferably 2.53.times.10.sup.-4 to
16.8.times.10.sup.-4 (mol).
[0087] It is preferred that the metal-containing catalyst used for
the polymerization of polylactic acid is inactivated with a
conventionally known deactivator prior to the use for polylactic
acid. Examples of such a deactivator include organic ligands
consisting of a group of chelate ligands having an imino group and
capable of coordinating to the polymerization metal catalyst.
[0088] Low oxidation number phosphoric acids having an acid number
of 5 or less, such as dihydride oxophosphoric acid (I), dihydride
tetraoxodiphosphoric acid (II, II), hydride trioxophosphoric acid
(III), dihydride pentaoxodiphosphoric acid (III), hydride
pentaoxodiphosphoric acid (II, IV), dodecaoxohexaphosphoric acid
(III), hydride octaoxotriphosphoric acid (III, IV, IV),
octaoxotriphosphoric acid (IV, III, IV), hydride
hexaoxodiphosphoric acid (III, V), hexaoxodiphosphoric acid (IV),
decaoxotetraphosphoric acid (IV), hendecaoxotetraphosphoric acid
(IV), and enneaoxotriphosphoric acid (V, IV, IV), etc., are also
exemplified.
[0089] Orthophosphoric acids represented by the formula:
xH.sub.2O.yP.sub.2O.sub.5 and satisfying x/y=3 are also
exemplified. Polyphosphoric acids called "diphosphoric acid,
triphosphoric acid, tetraphosphoric acid, pentaphosphoric acid, and
the like" according to the degree of condensation and satisfying
2>x/y>1, and mixtures thereof are also exemplified.
Metaphosphoric acids satisfying x/y=1, especially trimetaphosphoric
acid and tetrametaphosphoric acid are also exemplified.
Ultraphosphoric acids having a network structure in which a part of
the phosphorus pentoxide structure remains and satisfying
1>x/y>0 (may be collectively referred to as "metaphosphoric
acid-based compounds") are also exemplified. Acidic salts of these
acids are also exemplified. Partial esters or whole esters of such
an acid with a monohydric or polyhydric alcohol, or a polyalkylene
glycol are also exemplified. Phosphono-substituted lower aliphatic
carboxylic acid derivatives of these acids, and the like are also
exemplified.
[0090] From the standpoint of catalyst deactivation ability,
orthophosphoric acids represented by the formula:
xH.sub.2O.yP.sub.2O.sub.5 and satisfying x/y=3 are preferred.
Polyphosphoric acids called "diphosphoric acid, triphosphoric acid,
tetraphosphoric acid, pentaphosphoric acid, and the like" according
to the degree of condensation and satisfying 2>x/y>1, and
mixtures thereof are also preferred. Metaphosphoric acids
satisfying x/y=1, especially trimetaphosphoric acid and
tetrametaphosphoric acid are also preferred. Ultraphosphoric acids
having a network structure in which a part of the phosphorus
pentoxide structure remains and satisfying 1>x/y>0 (may be
collectively referred to as "metaphosphoric acid-based compounds")
are also preferred. Acidic salts of these acids are also preferred.
Partial esters of such an acid with a monohydric or polyhydric
alcohol, or a polyalkylene glycol are also preferred.
[0091] The metaphosphoric acid-based compound which is used in the
present invention includes cyclic metaphosphoric acids in which
about 3 to 200 phosphoric acid units are condensed, ultra-region
metaphosphoric acids having a three-dimensional network structure,
and (alkali metal salts, alkaline earth metal salts, and onium
salts) thereof. Above of all, cyclic sodium metaphosphate,
ultra-region sodium metaphosphate, dihexylphosphonoethyl acetate
(hereinafter sometimes abbreviated as DHPA) of a
phosphono-substituted lower aliphatic carboxylic acid derivative,
and the like are suitably used.
[0092] The polylactic acid is preferably one having a lactide
content of 5,000 ppm or less. The lactide contained in the
polylactic acid deteriorates the resin and worsens the color tone
at the time of melting processing, and as the case may be, there is
a concern that it makes unusable as a product. Although the
poly(L-lactic acid) and/or poly(D-lactic acid) immediately after
melt ring-opening polymerization generally contains 1 to 5% by
weight of the lactide, the content of lactide can be reduced to a
preferred range in any stage between the end of polymerization of
poly(L-lactic acid) and/or poly(D-lactic acid) and molding of
polylactic acid by carrying out conventionally known lactide
reduction methods, namely, a vacuum devolatilization method with a
single-screw or multi-screw extruder, or a high-vacuum treatment
within a polymerizer, or the like alone or in combination.
[0093] The lower the lactide content, the more enhanced the melt
stability and moist heat stability of the resin. However, since the
lactide has such an advantage that it reduces the melt viscosity of
the resin, it is rational and economical to set the lactide content
to a value suitable for a desired purpose. That is, it is rational
to set the lactide content to 1,000 ppm or less so as to achieve
practical melt stability. The lactide content is selected within
the range of more preferably 700 ppm or less, still more preferably
500 ppm or less, and especially preferably 100 ppm or less. When
the polylactic acid component has the lactide content of the
foregoing range, there are brought such advantages that the
stability of the resin at the time of melt molding of a molded
article of the present invention is enhanced; and that the molded
article can be efficiently produced, and the moist heat stability
and low gas properties of the molded article can be increased.
[0094] The stereocomplex polylactic acid can be obtained by
bringing poly(L-lactic acid) and poly(D-lactic acid) into contact
with each other in a weight ratio in the range of 10/90 to 90/10,
preferably bringing them into melt contact with each other, and
more preferably melt kneading them together. A contact temperature
is in the range of preferably 220 to 290.degree. C., more
preferably 220 to 280.degree. C., and still more preferably 225 to
275.degree. C. from the viewpoints of enhancements of the stability
at the time of melting of polylactic acid and the stereocomplex
crystallization degree.
[0095] Although the melt kneading method is not particularly
limited, a conventionally known batch type or continuous type melt
mixer is preferably used. For example, a melt stirring tank, a
single-screw or double-screw extruder, a kneader, an anaxial
basket-type stirring tank, "VIBOLAC (registered trademark)",
manufactured by Sumitomo Heavy Industries, Inc., N-SCR,
manufactured by Mitsubishi Heavy Industries, Ltd., a spectacle
blade, a lattice blade, or a Kenix type stirrer, manufactured by
Hitachi, Ltd., or a tubular polymerizer equipped with a Sulzer SMLX
type static mixer can be used. Above all, an anaxial basket type
stirring tank that is a self-cleaning type polymerizer, N-SCR, a
double-screw extruder, and the like are preferred from the
viewpoint of productivity and quality, especially color tone of the
polylactic acid.
<Hydrolysis Regulator (Component B)>
[0096] In the present invention, the hydrolysis regulator
(component B) is an agent for sealing an end group of the resin
(component A) and an acidic group generated by decomposition. That
is, the hydrolysis regulator (component B) is an agent having an
effect for inhibiting the autocatalysis of the resin (component A)
to delay the hydrolysis.
[0097] As the acidic group, at least one member selected from the
group consisting of a carboxyl group, a sulfonic acid group, a
sulfinic acid group, a phosphoric acid group, and a phosphinic acid
group is exemplified. In the present invention, a carboxyl group is
especially exemplified.
[0098] Since the requirement for use is concerned with the use in
hot water at a higher temperature than 135.degree. C., it is
preferred that the component B has water resistance at 120.degree.
C. of 95% or more and reactivity with an acidic group at
190.degree. C. of 50% or more.
[0099] The water resistance at 120.degree. C. as referred to herein
is, for example, a value expressed by the following equation (ii)
by using 1) a calculated value of an agent remaining without being
changed after the 5-hour treatment, the value being calculated by
means of analysis of a dissolved portion at the time after adding 2
g of water to a system having 1 g of the component B dissolved in
50 mL of dimethyl sulfoxide and stirring the resultant at
120.degree. C. for 5 hours while refluxing, or 2) in the case where
the component B is not soluble in dimethyl sulfoxide, a calculated
value determined by performing the same treatment as that in the
foregoing 1) using a solvent capable of dissolving the component B
therein and having hydrophilicity. Incidentally, in 2), when a
boiling point of the solvent to be used is lower than 120.degree.
C., the solvent was mixed with dimethyl sulfoxide in a range where
at least a part of the component B is soluble therein, and 50 mL of
the mixed solvent was used. Although a mixing proportion may be
generally chosen within the range of 1/2 to 2/1, it is not
particularly limited so long as the above-described requirement is
satisfied.
[0100] In general, so long as the solvent which is used in 2) is
selected from tetrahydrofuran, N,N-dimethylformamide, and ethyl
acetate, the component B is soluble therein.
Water resistance (%)=[(Amount of the agent after the 5-hour
treatment)/(Initial amount of the agent)].times.100 (ii)
[0101] In the case of evaluating an instable agent for the water
resistance, a part of the agent is denatured by the hydrolysis, and
the sealing ability of the acidic group is lowered. In the case of
using such an agent in high-temperature hot water, the agent is
deactivated by the water, and the ability for sealing the target
acidic group is remarkably lowered. In view of the foregoing, the
water resistance at 120.degree. C. is more preferably 97% or more,
still more preferably 99% or more, and especially preferably 99.9%
or more. That is, when the water resistance is 99.9% or more,
namely the agent is stable in high-temperature hot water, the
reaction with the acidic group can be performed selectively and
efficiently.
[0102] The reactivity with an acidic group at 190.degree. C. as
referred to herein is, for example, a value obtained by measuring a
carboxyl group concentration regarding a resin composition obtained
by adding the agent in an amount such that the group of the
hydrolysis regulator, reacting with the carboxyl group, is
corresponding to 1.5 equivalents to the carboxyl group
concentration of the polylactic acid for evaluation to 100 parts by
weight of the polylactic acid for evaluation, followed by melt
kneading under a nitrogen atmosphere at a resin temperature of
190.degree. C. and at a rotation rate of 30 rpm for 1 minute by
using a Labo Plasto mill (manufactured by Toyo Seiki Seisaku-Sho,
Ltd.), the value being given according to the following equation
(iii).
Reactivity (%)=[{(Carboxyl group concentration of polylactic acid
for evaluation)-(Carboxyl group concentration of resin
composition)}/(Carboxyl group concentration of polylactic acid for
evaluation)].times.100 (iii)
[0103] The polylactic acid for evaluation is preferably one having
an MW of 120,000 to 200,000 and a carboxyl group concentration of
10 to 30 equivalents/ton. As such a polylactic acid, for example,
polylactic acid "NW3001D", manufactured by NatureWorks LLC (MW:
150,000, carboxyl group concentration: 22.1 equivalents/ton) and
the like can be suitably used. In that case, a value of the
reactivity can be determined by measuring a carboxyl group
concentration regarding a resin composition obtained by adding the
agent in an amount such that the group of the hydrolysis regulator,
reacting with the carboxyl group, is 33.15 equivalents/ton,
followed by melt kneading under a nitrogen atmosphere at a resin
temperature of 190.degree. C. and at a rotation rate of 30 rpm for
1 minute by using a Labo Plasto mill (manufactured by Toyo Seiki
Seisaku-Sho, Ltd.).
[0104] Besides, the reactivity with an acidic group may also be
given by the equivalent evaluation.
[0105] In the case of evaluating a stable agent for the reactivity,
even when kneading is performed under the above-described
condition, the carboxyl group concentration of the resin
composition does not substantially change. In the case of using
such an agent in high-temperature hot water, the ability for
sealing the target acidic group is not substantially exhibited, and
therefore, the decomposition of the resin (component A) cannot be
inhibited.
[0106] In view of the foregoing, the reactivity with an acidic
group at 190.degree. C. is more preferably 60% or more, still more
preferably 70% or more, and especially preferably 80% or more. That
is, when the reactivity is 80% or more, namely the reactivity with
an acidic group in high-temperature hot water is high, the reaction
with the acidic group can be efficiently performed.
[0107] It is important that the hydrolysis regulator (component B)
of the present invention has water resistance at 120.degree. C. of
95% or more and reactivity with an acidic group at 190.degree. C.
of 50% or more. That is, in a very stable agent, though the water
resistance is a high value, the reactivity with an acidic group is
a low value, and in that case, the ability for sealing the target
acidic group in high-temperature hot water is not substantially
exhibited. In a very instable agent, though the reactivity with an
acidic group is a high value, the water resistance is a low value,
and in that case, the agent is deactivated with water in
high-temperature hot water, and therefore, the ability for sealing
the target acidic group is remarkably lowered.
[0108] In view of the foregoing, the hydrolysis regulator having
high water resistance and reactivity with an acidic group is
suitably used in the present invention.
[0109] Examples of the component B include addition reaction type
compounds, such as carbodiimide compounds, isocyanate compounds,
epoxy compounds, oxazoline compounds, oxazine compounds, aziridine
compounds, etc.
[0110] These compounds can be used in combination of two or more
thereof. From the viewpoints of water resistance and reactivity
with an acidic group, carbodiimide compounds are preferably
exemplified.
[0111] As the carbodiimide compound, a compound having a basic
structure represented by the following general formula (I) or (II)
can be exemplified.
R--N.dbd.C.dbd.N--R' (I)
[0112] (In the formula, each of R and R' is independently an
aliphatic group having 1 to 20 carbon atoms, an alicyclic group
having 3 to 20 carbon atoms, an aromatic group having 5 to 15
carbon atoms, or a combination thereof, and may contain a hetero
atom; and R and R' may be bonded to each other to form a cyclic
structure, and may form two or more cyclic structures through a
spiro structure or the like.)
##STR00006##
[0113] (In the formula, each of R and R'' is independently an
aliphatic group having 1 to 20 carbon atoms, an alicyclic group
having 3 to 20 carbon atoms, an aromatic group having 5 to 15
carbon atoms, or a combination thereof, and may contain a hetero
atom; and n is an integer of 2 to 1,000.)
[0114] From the viewpoint of stability or easiness of handling,
aromatic carbodiimide compounds are more preferred. Examples
thereof include aromatic carbodiimide compounds represented by the
following formulae (2) and (3).
##STR00007##
[0115] (In the formula, each of R.sub.1 to R.sub.4 is independently
an aliphatic group having 1 to 20 carbon atoms, an alicyclic group
having 3 to 20 carbon atoms, an aromatic group having 5 to 15
carbon atoms, or a combination thereof, and may contain a hetero
atom; each of X and Y is independently a hydrogen atom, an
aliphatic group having 1 to 20 carbon atoms, an alicyclic group
having 3 to 20 carbon atoms, an aromatic group having 5 to 15
carbon atoms, or a combination thereof, and may contain a hetero
atom; and the respective aromatic rings may be bonded to each other
via a substituent to form a cyclic structure, and may form two or
more cyclic structures through a spiro structure or the like.)
##STR00008##
[0116] (In the formula, each of R.sub.5 to R.sub.7 is independently
an aliphatic group having 1 to 20 carbon atoms, an alicyclic group
having 3 to 20 carbon atoms, an aromatic group having 5 to 15
carbon atoms, or a combination thereof, and may contain a hetero
atom; and n is an integer of 2 to 1,000.)
[0117] Specific examples of such an aromatic carbodiimide compound
include polycarbodiimides synthesized by subjecting
bis(2,6-diisopropylphenyl) carbodiimide or
1,3,5-triisopropylbenzene-2,4-diisocyanate to a decarboxylation
condensation reaction, a combination of these two kinds, and the
like.
[0118] In the present invention, from the viewpoint of using in
high-temperature hot water, bis(2,6-diisopropylphenyl) carbodiimide
can be suitably used.
[0119] As for bis(2,6-diisopropylphenyl) carbodiimide, from the
viewpoints of water resistance and reactivity, its purity is
desirably high as far as possible, and it is preferably 95% or
more, more preferably 97% or more, and still more preferably 99% or
more (here, the purity is determined from an area obtained by the
measurement by means of HPLC as described in the working examples
as described later).
[0120] As for bis(2,6-diisopropylphenyl) carbodiimide, from the
viewpoints of water resistance and reactivity, a total sum content
of compounds represented by the following formulae (4) and (5) is
preferably 5% or less, more preferably 3% or less, and still more
preferably 1% or less (here, the total sum content of the compounds
represented by the following formulae (4) and (5) is determined by
the measurement by means of .sup.1H-NMR as described in the working
examples as described later).
[0121] In the case where the total sum content of the compounds
represented by the following formulae (4) and (5) is 5% or less,
the effect in high-temperature hot water is more enhanced. Although
this enhancement of the effect cannot be confirmed in warm water at
about 80.degree. C., it can be confirmed that a meaningful
difference in hot water at a high temperature of at least
180.degree. C. or higher is exhibited, and from the viewpoint of
water resistance of the compounds represented by the following
formulae (4) and (5), it may be conjectured that a meaningful
difference is exhibited in a high-temperature region of 135.degree.
C. or higher.
##STR00009##
[0122] (In the formula, each of R.sub.8 to R.sub.11 is an aliphatic
group having 3 carbon atoms, and at least one of them is a propyl
group, with the other group or groups being an isopropyl
group.)
##STR00010##
[0123] (In the formula, each of R.sub.12 to R.sub.15 is an
aliphatic group having 3 carbon atoms, and at least one group of
them is substituted on a position other than the ortho
position.)
[0124] As a method of obtaining bis(2,6-diisopropylphenyl)
carbodiimide having a high purity, a generally known purification
method can be adopted. As a specific method thereof, distillation,
recrystallization, washing, extraction, reprecipitation, column
chromatography, and the like are exemplified.
[0125] In particular, in the case of purifying only
bis(2,6-diisopropylphenyl)carbodiimide from a mixture of
bis(2,6-diisopropylphenyl)carbodiimide and the compound represented
by the foregoing formula (4) or (5), since the both compounds have
the same molecular weight and resemble each other in terms of an
affinity with a solvent, purification by means of recrystallization
is preferred.
[0126] As for the solvent which is used for the recrystallization,
any solvent is usable so long as it does not react with
bis(2,6-diisopropylphenyl)carbodiimide, and for example, alcohols,
such as methanol, ethanol, etc., and alkanes, such as hexane, etc.,
can be used. A combination of two or more kinds of solvents may be
used.
<Resin Composition>
[0127] The resin composition of the present invention satisfies any
one of the following A1 to A3:
A1: In hot water at an arbitrary temperature of 135.degree. C. to
160.degree. C., after 3 hours, not only a resin composition-derived
acidic group concentration is 30 equivalents/ton or less, but also
a weight of a water-insoluble matter of the resin composition is
50% or more, and after 24 hours, a weight of a water-insoluble
matter of the resin composition is 50% or less; A2: In hot water at
an arbitrary temperature of 160.degree. C. to 180.degree. C., after
2 hour, not only a resin composition-derived acidic group
concentration is 30 equivalents/ton or less, but also a weight of a
water-insoluble matter of the resin composition is 50% or more, and
after 24 hours, a weight of a water-insoluble matter of the resin
composition is 50% or less; and A3: In hot water at an arbitrary
temperature of 180.degree. C. to 220.degree. C., after 1 hour, not
only a resin composition-derived acidic group concentration is 30
equivalents/ton or less, but also a weight of a water-insoluble
matter of the resin composition is 50% or more, and after 24 hours,
a weight of a water-insoluble matter of the resin composition is
50% or less.
[0128] In order that the resin composition of the present invention
may exhibit the desired performance, it is important to control the
resin composition so as to be quickly decomposed after keeping the
weight and shape of the resin in hot water at a higher temperature
than 135.degree. C. for a fixed period of time. Although the fixed
period of time is determined according to an application, it is
preferably any of 10 minutes to 12 hours. From the viewpoint of
exhibiting the desired performance, the fixed period of time is
more preferably any of 30 minutes to 6 hours, and still more
preferably any of 30 minutes to 4 hours.
[0129] As for the matter of keeping the weight and shape of the
resin, it is preferred that the weight of the water-insoluble
matter of the resin composition is 50% or more; and that the amount
of volume change expressing the shape is 50% or less. For example,
even when the weight of the water-insoluble matter of the resin
composition is 50% or more, if it is in the completely hydrolyzed
state, it may not be said that the weight and shape of the resin
are kept. From the viewpoint of exhibiting the desired performance,
the weight of the water-insoluble matter of the resin composition
is more preferably 70% or more, and still more preferably 90% or
more. The amount of volume change expressing the shape is more
preferably 30% or less, and still more preferably 10% or less.
[0130] Here, the weight and the amount of volume change of the
shape of the resin are, for example, values given by the following
evaluations.
[0131] A closed melting crucible (manufactured by OM Lab-Tech Co.,
Ltd., MR-28, capacity: 28 mL) preheated at 110.degree. C. is
charged with 300 mg of the resin composition and 12 mL of distilled
water and hermetically sealed, and the crucible is allowed to stand
within a hot air dryer (manufactured by Koyo Thermo Systems Co.,
Ltd., KLO-45M,) previously kept at a prescribed temperature.
[0132] After allowing the crucible to stand, a time at which the
temperature in the interior of the crucible reaches a prescribed
test temperature after the crucible is allowed to stand in the hot
air dryer is defined as a point of time of starting the test, at a
point of time when a certain period of time elapses from this point
of time of starting the test, the crucible is taken out from the
hot air dryer. The crucible taken out from the hot air dryer is
air-cooled for 20 minutes and then cooled for 10 minutes by means
of water cooling to ordinary temperature, and thereafter, the
crucible is opened to recover the sample and water in the interior
of the crucible.
[0133] The sample and water in the interior of the crucible are
subjected to filtration using a filter paper (in conformity with
JIS P3801:1995, class 5A); the resin composition remaining on the
filter paper is dried at 60.degree. C. under a vacuum of 133.3 Pa
or less for 3 hours; thereafter, the weight of the resin
composition and the volume of the shape are measured; and the
weight and the amount of volume change of the shape of the resin
are determined according to the following equations (iv) and
(v).
Weight (%)=[(Weight of resin composition after treatment for a
fixed period of time)/(Weight of resin composition at the initial
stage)].times.100 (iv)
Amount of volume change of shape (%)=[(Volume of resin composition
after treatment for a fixed period of time)/(Volume of resin
composition at the initial stage)].times.100 (v)
[0134] Here, the volume of the shape is a value determined by
measuring the resin composition by a stereoscopic microscope.
[0135] As the stereomicroscope, M205C, manufactured by Leica
Microsystems, and the like can be used.
[0136] Incidentally, in this evaluation, with respect to the size
of the resin composition, for example, so far as a pellet-like
material is concerned, those close to a cube or rectangular
parallelepiped of 0.5 mm to 5 mm in each side; so far as a fibrous
material is concerned, fibers having a yarn thickness of 1 .mu.m to
1,000 .mu.m and a yarn length of 1 mm to 40 mm; and so far as a
filmy material is concerned, films having a thickness of 50 .mu.m
to 1,000 .mu.m and a length of each of the length and the width of
5 mm to 50 mm, can be generally used.
[0137] Besides, the weight and the amount of volume change of the
shape of the resin may also be given by the equivalent evaluation.
The matter that the resin is quickly decomposed means the state in
which the hydrolysis of the component A is promoted by the
autocatalysis, and the concentration of the acidic group
exponentially increases. Conversely, during the period when the
concentration of the acidic group is kept low by the component B,
the decomposition of the component A becomes gentle. For that
reason, during the period when the weight and shape of the resin
are kept, it is preferred that the concentration of the acidic
group derived from the resin composition is 30 equivalents/ton or
less.
[0138] In the case where the concentration of the acidic group is
more than 30 equivalents/ton, the hydrolysis of the component A is
promoted due to the autocatalysis, and the effect of the component
B is not sufficiently exhibited. When the concentration of the
acidic group is lower, the change of the weight of the resin
composition or the shape can be inhibited. Therefore, from the
viewpoint that the desired performance is exhibited, during the
period when the weight and shape of the resin are kept, the
concentration of the acidic group derived from the resin
composition is more preferably 20 equivalents/ton or less, still
more preferably 10 equivalents/ton or less, and especially
preferably 3 equivalents/ton or less.
[0139] Here, the concentration of the acidic group derived from the
resin composition can be, for example, determined by preparing a
resin composition in the same manner as that used in the
above-described evaluation for determining the weight and the
amount of volume change of the shape of the resin and measuring the
resulting resin composition by means of .sup.1H-NMR.
[0140] The resin composition of the present invention can be
suitably used in hot water at an arbitrary temperature of
135.degree. C. to 220.degree. C. When the temperature is
135.degree. C. or lower, there may be the case where the desired
performance can be exhibited by using only the component A. In
addition, when even the temperature is higher than 220.degree. C.,
there may be the case where even the resin composition of the
present invention is immediately decomposed, so that the desired
performance cannot be exhibited. For that reason, the resin
composition of the present invention can be more suitably used in
hot water at an arbitrary temperature of 150.degree. C. to
220.degree. C., can be still more suitably used in hot water at an
arbitrary temperature of 170.degree. C. to 210.degree. C., and can
be yet still more suitably used in hot water at an arbitrary
temperature of 190.degree. C. to 210.degree. C.
[0141] The resin composition of the present invention satisfies any
one of the following A1 to A3:
A1: In hot water at an arbitrary temperature of 135.degree. C. to
160.degree. C., after 3 hours, not only a resin composition-derived
acidic group concentration is 30 equivalents/ton or less, but also
a weight of a water-insoluble matter of the resin composition is
50% or more, and after 24 hours, a weight of a water-insoluble
matter of the resin composition is 50% or less; A2: In hot water at
an arbitrary temperature of 160.degree. C. to 180.degree. C., after
2 hour, not only a resin composition-derived acidic group
concentration is 30 equivalents/ton or less, but also a weight of a
water-insoluble matter of the resin composition is 50% or more, and
after 24 hours, a weight of a water-insoluble matter of the resin
composition is 50% or less; and A3: In hot water at an arbitrary
temperature of 180.degree. C. to 220.degree. C., after 1 hour, not
only a resin composition-derived acidic group concentration is 30
equivalents/ton or less, but also a weight of a water-insoluble
matter of the resin composition is 50% or more, and after 24 hours,
a weight of a water-insoluble matter of the resin composition is
50% or less.
[0142] The range where the resin composition of the present
invention can be suitably used varies with the temperature. In A1
to A3, at a time earlier than after the prescribed fixed period of
time (1 hour, 2 hours, or 3 hours), it is preferred that the resin
composition-derived acidic group concentration is 30
equivalents/ton or less, and the weight of the water-insoluble
matter of the resin composition is 50% or more.
[0143] In A1, it is expressed that the fixed period of time is 3
hours and during that time, the weight and shape of the resin are
kept. From the viewpoint of exhibiting the desired performance in
the excavation technology in the oil field or the like, in hot
water at an arbitrary temperature of 135.degree. C. to 160.degree.
C., after a fixed period of time longer than 2 hours as defined in
the present invention, the resin composition-derived acidic group
concentration may be 30 equivalents/ton or less, and the weight of
the water-insoluble matter of the resin composition may be 50% or
more.
[0144] In A2, it is expressed that the fixed period of time is 2
hours and during that time, the weight and shape of the resin are
kept. From the viewpoint of exhibiting the desired performance in
the excavation technology in the oil field or the like, in hot
water at an arbitrary temperature of 160.degree. C. to 180.degree.
C., after a fixed period of time longer than 2 hours as defined in
the present invention, the resin composition-derived acidic group
concentration may be 30 equivalents/ton or less, and the weight of
the water-insoluble matter of the resin composition may be 50% or
more.
[0145] In A3, it is expressed that the fixed period of time is 1
hour and during that time, the weight and shape of the resin are
kept. From the viewpoint of exhibiting the desired performance in
the excavation technology in the oil field or the like, in hot
water at an arbitrary temperature of 180.degree. C. to 220.degree.
C., after a fixed period of time longer than 1 hour as defined in
the present invention, the resin composition-derived acidic group
concentration may be 30 equivalents/ton or less, and the weight of
the water-insoluble matter of the resin composition may be 50% or
more.
[0146] After the fixed period of time prescribed in each of A1 to
A3 (1 hour, 2 hours, or 3 hours), the effect for sealing the acidic
group by the component B vanishes, the decomposition of the resin
is promoted due to the autocatalysis of the acidic group, and
following that, the concentration of the acidic group exponentially
increases. Furthermore, as the decomposition proceeds, the resin
becomes a water-soluble monomer, whereby it becomes soluble in
water. The matter that the instant phenomenon occurs quickly as far
as possible after the weight and shape of the resin are kept for a
fixed period of time is suitable on the occasion of using the resin
composition of the present invention in the excavation technology
in the oil field or the like. For that reason, it is preferred that
after 24 hours, the weight of the water-insoluble matter of the
resin composition is 50% or less. For the foregoing reason, it is
more preferred that after 18 hours, the weight of the
water-insoluble matter of the resin composition is 50% or less; it
is still more preferred that after 12 hours, the weight of the
water-insoluble matter of the resin composition is 50% or less; and
it is yet still more preferred that after 6 hours, the weight of
the water-insoluble matter of the resin composition is 50% or
less.
[0147] As for the resin composition of the present invention, it is
preferred that in hot water at an arbitrary temperature of
135.degree. C. to 220.degree. C., after 100 hours, the weight of
the water-insoluble matter of the resin composition is 10% or less.
For example, on the occasion of using the resin composition in the
excavation technology in the oil field or the like, the resin
composition is dissolved in water quickly after keeping the weight
and shape of the resin for a fixed period of time, whereby it can
effectively work. For that reason, it is preferred that in hot
water at an arbitrary temperature of 135.degree. C. to 220.degree.
C., after 100 hours, the weight of the water-insoluble matter of
the resin composition is 10% or less. From the viewpoints of
treatment in water after the use and exhibition of the desired
performance, the water-insoluble matter is low as far as possible,
and after 100 hours, the weight of the water-insoluble matter of
the resin composition is more preferably 5% or less, and still more
preferably 1% or less.
[0148] It is preferred that a heat deformation temperature of the
resin composition of the present invention is 135.degree. C. to
300.degree. C. Here, the heat deformation temperature refers to a
melting point or softening point of the resin composition. Since
the resin composition is supposed to be used in hot water at a
higher temperature than 135.degree. C., when the heat deformation
temperature of the resin composition is higher, the resin
composition can be used in a wide temperature region. Meanwhile,
when the heat deformation temperature is 300.degree. C. or less,
molding of the resin composition of the present invention is
relatively easy. For that reason, the heat deformation temperature
of such a resin composition is more preferably 150.degree. C. to
300.degree. C., still more preferably 165.degree. C. to 300.degree.
C., yet still more preferably 170.degree. C. to 300.degree. C.,
even yet still more preferably 175.degree. C. to 285.degree. C.,
and especially preferably 180.degree. C. to 285.degree. C.
[0149] In the resin composition of the present invention, an
addition amount of the component B is 1 to 30 parts by weight based
on 100 parts by weight of a total sum of the component A and the
component B. When the addition amount of the component B is less
than 1 part by weight, there may be the case where the sufficient
effect for sealing the acidic group is not exhibited in hot water
at a higher temperature than 135.degree. C. When it is more than 30
parts by weight, there may be the case where bleedout of the
component B from the resin composition, worsening of moldability,
or degeneration of properties of a substrate takes place. From such
viewpoints, the addition amount of the component B is preferably
1.5 to 20 parts by weight, more preferably 2 to 15 parts by weight,
still more preferably 2.5 to 12.5 parts by weight, and especially
preferably 3.0 to 10 parts by weight based on 100 parts by weight
of a total sum of the component A and the component B.
<Production Method of Resin Composition>
[0150] The resin composition of the present invention can be
produced by melt kneading the resin containing, as a main
component, a water-soluble monomer and having autocatalysis
(component A) and the hydrolysis regulator (component B).
[0151] Incidentally, in the case of adopting polylactic acid as the
resin containing, as a main component, a water-soluble monomer and
having autocatalysis (component A), poly(L-lactic acid) and
poly(D-lactic acid), each of which is the resin containing, as a
main component, a water-soluble monomer and having autocatalysis
(component A), and the hydrolysis regulator (component B) are mixed
to form a stereocomplex polylactic acid, and simultaneously, the
resin composition of the present invention can also be produced.
The resin composition of the present invention can also be produced
by mixing poly(L-lactic acid) and poly(D-lactic acid) to form
stereocomplex polylactic acid and then mixing the hydrolysis
regulator (component B).
[0152] The method of adding the hydrolysis regulator (component B)
to the resin containing, as a main component, a water-soluble
monomer and having autocatalysis (component A) and mixing them is
not particularly limited, and a conventionally known method, such
as a method of adding as a solution, a melt, or a master batch of
the resin containing, as a main component, a water-soluble monomer
and having autocatalysis (component A) to be applied; a method of
bringing a solid of the resin containing, as a main component, a
water-soluble monomer and having autocatalysis (component A) into
contact with a liquid having the hydrolysis regulator (component B)
dissolved, dispersed or melted therein, thereby penetrating the
hydrolysis regulator (component B) thereinto; and the like can be
adopted.
[0153] In the case of adopting a method of adding as a solution, a
melt, or a master batch of the resin containing, as a main
component, a water-soluble monomer and having autocatalysis
(component A) to be applied, a method of addition using a
conventionally known kneading device can be adopted. On the
occasion of kneading, a kneading method in a solution state or a
kneading method in a molten state is more preferred from the
viewpoint of uniform kneading properties. The kneading device is
not particularly limited, and conventionally known vertical
reaction vessels, mixing tanks, and kneading tanks, or single-screw
or multi-screw horizontal kneading devices, for example,
single-screw or multi-screw extruders and kneader, and the like are
exemplified. A mixing time is not particularly specified, and
though it varies with the mixing device or mixing temperature, a
time of 0.1 minutes to 2 hours, preferably 0.2 minutes to 60
minutes, and more preferably 0.2 minutes to 30 minutes is
selected.
[0154] As the solvent, those which are inert to the resin
containing, as a main component, a water-soluble monomer and having
autocatalysis (component A) and the hydrolysis regulator (component
B) can be used. In particular, a solvent which has an affinity with
the both components and at least partially dissolves the both
components therein is preferred.
[0155] As the solvent, for example, hydrocarbon-based solvents,
ketone-based solvents, ester-based solvents, ether-based solvents,
halogen-based solvents, amide-based solvents, and the like can be
used.
[0156] Examples of the hydrocarbon-based solvent include hexane,
cyclohexane, benzene, toluene, xylene, heptane, decane, and the
like. Examples of the ketone-based solvent include acetone, methyl
ethyl ketone, diethyl ketone, cyclohexanone, isophorone, and the
like.
[0157] Examples of the ester-based solvent include ethyl acetate,
methyl acetate, ethyl succinate, methyl carbonate, ethyl benzoate,
diethylene glycol diacetate, and the like. Examples of the
ether-based solvent include diethyl ether, dibutyl ether,
tetrahydrofuran, dioxane, diethylene glycol dimethyl ether,
triethylene glycol diethyl ether, diphenyl ether, and the like.
Examples of the halogen-based solvent include dichloromethane,
chloroform, tetrachloromethane, dichloroethane,
1,1',2,2'-tetrachloroethane, chlorobenzene, dichlorobenzene, and
the like. Examples of the amide-based solvent include formamide,
N,N-dimethylformamide, N,N-dimethylacetamide,
N-methyl-2-pyrrolidone, and the like. These solvents can be used
alone or as a mixed solvent, if desired.
[0158] In the present invention, the solvent is applied in an
amount in the range of 1 to 1,000 parts by weight based on 100
parts by weight of the resin composition. When the amount of the
solvent is less than 1 part by weight, there is no meaning for the
application of the solvent. Although an upper limit value of the
use amount of the solvent is not particularly limited, it is about
1,000 parts by weight from the viewpoints of operability and
reaction efficiency.
[0159] In the case of adopting a method of bringing a solid of the
resin containing, as a main component, a water-soluble monomer and
having autocatalysis (component A) into contact with a liquid
having the hydrolysis regulator (component B) dissolved, dispersed
or melted therein, thereby penetrating the hydrolysis regulator
(component B), a method of bringing a solid of the resin
containing, as a main component, a water-soluble monomer and having
autocatalysis (component A) into contact with the hydrolysis
regulator (component B) dissolved in a solvent as described above;
a method of bringing a solid of the resin containing, as a main
component, a water-soluble monomer and having autocatalysis
(component A) into contact with an emulsion liquid of the
hydrolysis regulator (component B); and the like can be
adopted.
[0160] As the contacting method, a method of dipping the resin
containing, as a main component, a water-soluble monomer and having
autocatalysis (component A); a method of coating the resin
containing, as a main component, a water-soluble monomer and having
autocatalysis (component A); a method of spraying onto the resin
containing, as a main component, a water-soluble monomer and having
autocatalysis (component A); and the like can be suitably
adopted.
[0161] Although it is possible to perform a sealing reaction of the
acidic group of the resin containing, as a main component, a
water-soluble monomer and having autocatalysis (component A) with
the hydrolysis regulator (component B) at a temperature of room
temperature (25.degree. C.) to about 300.degree. C., the sealing
reaction is more promoted at a temperature in the range of
preferably 50 to 280.degree. C., and more preferably 100 to
280.degree. C. from the viewpoint of reaction efficiency. As for
the resin containing, as a main component, a water-soluble monomer
and having autocatalysis (component A), the reaction is liable to
be more advanced at a temperature at which it is melted; however,
in order to inhibit volatilization, decomposition, or the like of
the hydrolysis regulator (component B), it is preferred to perform
the reaction at a temperature lower than 300.degree. C. For the
purposes of lowering the melting temperature of the resin
containing, as a main component, a water-soluble monomer and having
autocatalysis (component A) and increasing the stirring efficiency,
it is effective to apply a solvent.
[0162] Although the reaction is sufficiently rapidly advanced in
the absence of a catalyst, a catalyst for promoting the reaction
can also be used. As the catalyst, catalysts which are generally
used for the hydrolysis regulator (component B) can be applied.
These can be used alone or in combination of two or more kinds
thereof. Although an addition amount of the catalyst is not
particularly limited, it is preferably 0.001 to 1 part by weight,
more preferably 0.01 to 0.1 parts by weight, and most preferably
0.02 to 0.1 parts by weight based on 100 parts by weight of the
resin composition.
[0163] In the present invention, the hydrolysis regulator
(component B) may be used in a combination of two or more kinds
thereof. For example, with respect to the hydrolysis regulator
(component B) for performing the sealing reaction of the acidic
group at the early stage of the resin containing, as a main
component, a water-soluble monomer and having autocatalysis
(component A) and the hydrolysis regulator (component B) for
performing the sealing reaction of the acidic group generated in
hot water at a higher temperature than 135.degree. C., separate
materials may be used.
[0164] Furthermore, it is preferred to jointly use an auxiliary
agent of the hydrolysis regulator (component B), namely an agent
for assisting the effect of the component B for the purpose of
delaying the hydrolysis. Although any known material can be used as
such an agent, for example, at least one compound selected from
hydrotalcite, an alkaline earth metal oxide, an alkaline earth
metal hydroxide, and an alkaline earth metal carbonate is
exemplified. A content of the auxiliary agent is preferably 0.1 to
30 parts by weight, more preferably 0.5 to 20 parts by weight, and
still more preferably 0.7 to 10 parts by weight based on 100 parts
by weight of the hydrolysis regulator (component B).
[0165] In the resin composition of the present invention, all of
known additives and fillers can be added and used within the range
where the effects of the invention are not lost. Examples thereof
include a stabilizer, a crystallization promoter, a filler, a
release agent, an antistatic agent, a plasticizer, an impact
resistance-improving agent, a terminal-sealing agent, and the
like.
[0166] Incidentally, from the viewpoint that the effects of the
invention are not lost, with respect to the additives, it is
important to not use a component which promotes the decomposition
of the resin containing, as a main component, a water-soluble
monomer and having autocatalysis (component A), for example, a
phosphoric acid component, a phosphite-based additive which is
decomposed in the resin composition to generate a phosphoric acid
component, or the like, or decrease its amount as far as possible,
or to reduce influences thereof by taking a method, such as
deactivation, etc. For example, a method of using a component
capable of achieving deactivation or retardation together with the
hydrolysis regulator (component B), or the like can be suitably
adopted.
<Stabilizer>
[0167] The resin composition of the present invention can contain a
stabilizer. As the stabilizer, those which are used for a
stabilizer of ordinary thermoplastic resins can be used. For
example, an antioxidant, a light stabilizer, and the like can be
exemplified. By compounding such an agent, a molded article having
excellent mechanical properties, moldability, heat resistance, and
durability can be obtained.
[0168] As the antioxidant, a hindered phenol-based compound, a
hindered amine-based compound, a phosphite-based compound, a
thioether-based compound, and the like can be exemplified.
[0169] Examples of the hindered phenol-based compound include
n-octadecyl-3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)-propionate,
n-octadecyl-3-(3'-methyl-5'-tert-butyl-4'-hydroxyphenyl)-propionate,
n-tetradecyl-3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)-propionate,
1,6-hexanediol-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionate],
1,4-butanediol-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionate],
2,2'-methylene-bis(4-methyl-tert-butylphenol), triethylene
glycol-bis([3-(3-t-butyl-5-methyl-4-hydroxyphenyl)-propionate],
tetrakis[methylene-3-(3',5'-di-tert-butyl-4-hydroxyphenyl)
propionate]methane,
3,9-bis[2-{3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy}-1,1-dim-
ethylethyl]2,4,8,10-tetraoxaspiro(5,5)undecane, and the like.
[0170] Examples of the hindered amine-based compound include
N,N'-bis-3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionyl
hexamethylenediamine,
N,N'-tetramethylene-bis[3-(3'-methyl-5'-tert-butyl-4'-hydr
oxyphenyl)propionyl]diamine,
N,N'-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionyl]hydrazine,
N-salicyloyl-N'-salicylidenehydrazine,
3-(N-salicyloyl)amino-1,2,4-triazole,
N,N'-bis[2-{3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl
oxy}ethyl]oxyamide, and the like. Triethylene
glycol-bis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl)-propionate],
tetrakis[methylene-3-(3',5'-di-tert-butyl-4-hydroxyphenyl)
propionate]methane, and the like are preferred.
[0171] The phosphite-based compound is preferably a compound having
at least one P--O bond bonded to an aromatic group. Specifically,
examples thereof include tris(2,6-di-tert-butylphenyl)phosphite,
tetrakis(2,6-di-tert-butylphenyl)4,4'-biphenylene phosphite,
bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol-di-phosphite,
2,2-methylenebis(4,6-di-tert-butylphenyl)octylphosphite,
4,4'-butylidene-bis(3-methyl-6-tert-butylphenyl-di-tridecyl)phosphite,
1,1,3-tris(2-methyl-4-ditridecylphosphite-5-tert-butylphenyl)butane,
tris(mixed mono- and di-nonylphenyl)phosphite,
tris(nonylphenyl)phosphite,
4,4'-isopropylidenebis(phenyl-dialkylphosphite),
2,4,8,10-tetra-tert-butyl-6-[3-(3-methyl-4-hydroxy-5-t-butylphenyl)propox-
y]dibenzo[d,f][1,3,2]dioxaphosphepin (SUMILIZER (registered
trademark) GP), and the like.
[0172] Specific examples of the thioether-based compound include
dilauryl thiodipropionate, ditridecyl thiodipropionate, dimyristyl
thiodipropionate, distearyl thiodipropionate,
pentaerythritol-tetrakis(3-laurylthiopropionate),
pentaerythritol-tetrakis(3-dodecylthiopropionate),
pentaerythritol-tetrakis(3-octadecylthiopropionate),
pentaerythritol-tetrakis(3-myristylthiopropionate),
pentaerythritol-tetrakis(3-stearylthiopropionate), and the
like.
[0173] As the light stabilizer, specifically, for example, a
benzophenone-based compound, a benzotriazole-based compound, an
aromatic benzoate-based compound, an oxalic anilide-based compound,
a cyanoacrylate-based compound, a hindered amine-based compound,
and the like can be exemplified.
[0174] Examples of the benzophenone-based compound include
benzophenone, 2,4-dihydroxybenzophenone,
2,2'-dihydroxybenzophenone, 2,2',4,4'-tetrahydroxybenzophenone,
2-hydroxy-4-methoxybenzophenone,
2,2'-dihydroxy-4,4'-dimethoxybenzophenone,
2,2'-dihydroxy-4,4'-dimethoxy-5-sulfobenzophenone,
2-hydroxy-4-octoxybenzophenone, 2-hydroxy-4-dodecyloxybenzophenone,
2-hydroxy-4-octoxybenzophenone,
2-hydroxy-4-methoxy-5-sulfobenzophenone,
5-chloro-2-hydroxybenzophenone, 2-hydroxy-4-octoxybenzophenone,
2-hydroxy-4-methoxy-2'-carboxybenzophenone,
2-hydroxy-4-(2-hydroxy-3-methyl-acryloxyisopropoxy)benzophenone,
and the like.
[0175] Examples of the benzotriazole-based compound include
2-(5-methyl-2-hydroxyphenyl)benzotriazole,
2-(3,5-di-tert-butyl-2-hydroxyphenyl)benzotriazole,
2-(3,5-di-tert-amyl-2-hydroxyphenyl)benzotriazole,
2-(3',5'-di-tert-butyl-4'-methyl-2'-hydroxyphenyl)benzotriazole,
2-(3,5-di-tert-amyl-2-hydroxyphenyl)-5-chlorobenzotriazole,
2-(5-tert-butyl-2-hydroxyphenyl)benzotriazole,
2-[2'-hydroxy-3',5'-bis(.alpha.,.alpha.-dimethylbenzyl)phenyl]benzotriazo-
le,
2-[2'-hydroxy-3',5'-bis(.alpha.,.alpha.-dimethylbenzyl)phenyl]-2H-benz-
otriazole, 2-(4'-octoxy-2'-hydroxyphenyl)benzotriazole, and the
like.
[0176] Examples of the aromatic benzoate-based compound include
alkylphenyl salicylates, such as p-tert-butylphenyl salicylate,
p-octylphenyl salicylate, etc.
[0177] Examples of the oxalic anilide-based compound include
2-ethoxy-2'-ethyloxalic acid bisanilide,
2-ethoxy-5-tert-butyl-2'-ethyloxalic acid bisanilide,
2-ethoxy-3'-dodecyloxalic acid bisanilide, and the like.
[0178] Examples of the cyanoacrylate-based compound include
ethyl-2-cyano-3,3'-diphenyl acrylate,
2-ethylhexyl-cyano-3,3'-diphenyl acrylate, and the like.
[0179] Examples of the hindered amine-based compound include
4-acetoxy-2,2,6,6-tetramethylpiperidine,
4-stearoyloxy-2,2,6,6-tetramethylpiperidine,
4-acryloyloxy-2,2,6,6-tetramethylpiperidine,
4-(phenylacetoxy)-2,2,6,6-tetramethylpiperidine,
4-benzoyloxy-2,2,6,6-tetramethylpiperidine,
4-methoxy-2,2,6,6-tetramethylpiperidine,
4-octadecyloxy-2,2,6,6-tetramethylpiperidine,
4-cyclohexyloxy-2,2,6,6-tetramethylpiperidine,
4-benzyloxy-2,2,6,6-tetramethylpiperidine,
4-phenoxy-2,2,6,6-tetramethylpiperidine,
4-(ethylcarbamoyloxy)-2,2,6,6-tetramethylpiperidine,
4-(cyclohexylcarbamoyloxy)-2,2,6,6-tetramethylpiperidine,
4-(phenylcarbamoyloxy)-2,2,6,6-tetramethylpiperidine,
bis(2,2,6,6-tetramethyl-4-piperidyl)carbonate,
bis(2,2,6,6-tetramethyl-4-piperidyl)oxalate,
bis(2,2,6,6-tetramethyl-4-piperidyl)malonate,
bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate,
bis(2,2,6,6-tetramethyl-4-piperidyl)adipate,
bis(2,2,6,6-tetramethyl-4-piperidyl)terephthalate,
1,2-bis(2,2,6,6-tetramethyl-4-piperidyloxy)-ethane,
.alpha.,.alpha.'-bis(2,2,6,6-tetramethyl-4-piperidyloxy)-p-xylene,
bis(2,2,6,6-tetramethyl-4-piperidyl)-tolylene-2,4-dicarbamate,
bis(2,2,6,6-tetramethyl-4-piperidyl)-hexamethylene-1,6-dicarbamate,
tris(2,2,6,6-tetramethyl-4-piperidyl)-benzene-1,3,5-tricarboxylate,
tris(2,2,6,6-tetramethyl-4-piperidyl)-benzene-1,3,4-tricarboxylate,
1-[2-{3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxy}-2,2,6,6-tetramet-
hylpiperidine, a condensate of 1,2,3,4-butane tetracarboxylic acid,
1,2,2,6,6-pentamethyl-4-piperidinol, and
.beta.,.beta.,.beta.',.beta.'-tetramethyl-3,9-[2,4,8,10-tetraoxaspiro(5,5-
)undecane]dimethanol, and the like.
[0180] In the present invention, the stabilizer component may be
used alone, or may be used in combination of two or more kinds
thereof. As the stabilizer component, a hindered phenol-based
compound and/or a benzotriazole-based compound is preferred.
[0181] A content of the stabilizer is preferably 0.01 to 3 parts by
weight, and more preferably 0.03 to 2 parts by weight based on 100
parts by weight of the resin containing, as a main component, a
water-soluble monomer and having autocatalysis (component A).
<Crystallization Accelerator>
[0182] The resin composition of the present invention can contain
an organic or inorganic crystallization accelerator. When the resin
composition contains the crystallization accelerator, a molded
article having excellent mechanical properties, heat resistance,
and moldability can be obtained.
[0183] That is, by applying the crystallization accelerator, a
molded article which is enhanced in moldability and crystallinity,
is thoroughly crystallized even by ordinary injection molding, and
is excellent in heat resistance and moist heat stability can be
obtained. In addition thereto, the time required for the
manufacture of a molded article can be drastically shortened, and
its economic effect is large.
[0184] A crystal nucleating agent which is generally used for
crystalline resins can be used as the crystallization accelerator
which is used in the present invention. All of an inorganic crystal
nucleating agent and an organic crystal nucleating agent can be
used.
[0185] Examples of the inorganic crystal nucleating agent include
talc, kaolin, silica, synthetic mica, clay, zeolite, graphite,
carbon black, zinc oxide, magnesium oxide, titanium oxide, calcium
carbonate, calcium sulfate, barium sulfate, calcium sulfide, boron
nitride, montmorillonite, neodymium oxide, aluminum oxide,
phenylphosphonate metal salts, and the like. Such an inorganic
crystal nucleating agent is preferably treated with a dispersion
aid of every sort in order to increase its dispersibility in the
composition and its effects and highly dispersed to such an extent
that its primary particle diameter is about 0.01 to 0.5 .mu.m.
[0186] Examples of the organic crystal nucleating agent include
organic carboxylic acid metal salts, such as calcium benzoate,
sodium benzoate, lithium benzoate, potassium benzoate, magnesium
benzoate, barium benzoate, calcium oxalate, disodium terephthalate,
dilithium terephthalate, dipotassium terephthalate, sodium laurate,
potassium laurate, sodium myristate, potassium myristate, calcium
myristate, barium myristate, sodium octacosanoate, calcium
octacosanoate, sodium stearate, potassium stearate, lithium
stearate, calcium stearate, magnesium stearate, barium stearate,
sodium montanate, calcium montanate, sodium toluoylate, sodium
salicylate, potassium salicylate, zinc salicylate, aluminum
dibenzoate, sodium .beta.-naphthoate, potassium .beta.-naphthoate,
sodium cyclohexanecarboxylate, etc.; and organic sulfonic acid
metal salts, such as sodium p-toluenesulfonate, sodium
sulfoisophthalate, etc.
[0187] Organic carboxylic acid amides, such as stearic acid amide,
ethylenebis(lauric amide), palmitic acid amide, hydroxystearic acid
amide, erucic acid amide, tris(t-butylamide) trimesate, etc.,
low-density polyethylene, high-density polyethylene,
polyisopropylene, polybutene, poly-4-methylpentene,
poly-3-methylbutene-1, polyvinyl cycloalkane, polyvinyl
trialkylsilane, branched type polylactic acid, a sodium salt of an
ethylene-acrylate copolymer, a sodium salt of a styrene-maleic
anhydride copolymer (so-called "ionomer"), benzylidene sorbitol and
a derivative thereof, for example, dibenzylidene sorbitol, etc.,
are exemplified.
[0188] Of these, talc and at least one member selected from organic
carboxylic acid metal salts are preferably used. The
crystallization accelerator which is used in the present invention
may be used alone, or may be used in combination of two or more
kinds thereof.
[0189] A content of the crystallization accelerator is preferably
0.01 to 30 parts by weight, and more preferably 0.05 to 20 parts by
weight based on 100 parts by weight of the resin containing, as a
main component, a water-soluble monomer and having autocatalysis
(component A).
<Filler>
[0190] The resin composition of the present invention can contain
an organic or inorganic filler. When the resin composition contains
a filler component, a molded article having excellent mechanical
properties, heat resistance, and die moldability can be
obtained.
[0191] Examples of the organic filler include chip fillers, such as
rice husk chips, wooden chips, bean curd refuse, old paper crushed
chips, apparel crushed chips, etc.; fibrous fillers, such as plant
fibers including cotton fibers, hemp fibers, bamboo fibers, wooden
fibers, kenaf fibers, jute fibers, banana fibers, coconut fibers,
and the like, pulp or cellulose fibers processed from these plant
fibers, animal fibers including silk, wool, Angora, cashmere, and
camel fibers, and the like, and synthetic fibers including
polyester fibers, nylon fibers, acrylic fibers, and the like; and
powdery fillers, such as paper powders, wooden powders, cellulose
powders, rice husk powders, fruit shell powders, chitin powders,
chitosan powders, protein powders, starch powders, etc. From the
viewpoint of moldability, powdery fillers, such as paper powders,
wooden powders, bamboo powders, cellulose powders, kenaf powders,
rice husk powders, fruit shell powders, chitin powders, chitosan
powders, protein powders, starch powders, etc., are preferred, and
paper powders, wooden powders, bamboo powders, cellulose powders,
and kenaf powders are more preferred. Paper powders and wooden
powders are still more preferred. Paper powders are especially
preferred.
[0192] Although organic fillers collected directly from natural
products may be used, organic fillers recycled from waste
materials, such as used paper, waste timber, used clothing, etc.,
may also be used. Conifers, such as yellow pine, cedar, cypress,
fir, etc., and broadleaf trees, such as beech, chinquapin,
eucalyptus, etc., and the like are preferred as the timber.
[0193] From the viewpoint of moldability, paper powders containing
an adhesive, especially an emulsion-based adhesive, such as a vinyl
acetate resin-based emulsion, an acrylic resin-based emulsion,
etc., which is generally used on the occasion of processing paper,
or a hot melt adhesive, such as a polyvinyl alcohol-based adhesive,
a polyamide-based adhesive, etc., or the like are preferably
exemplified.
[0194] In the present invention, though a compounding amount of the
organic filler is not particularly limited, from the viewpoints of
moldability and heat resistance, it is preferably 1 to 300 parts by
weight, more preferably 5 to 200 parts by weight, still more
preferably 10 to 150 parts by weight, and especially preferably 15
to 100 parts by weight based on 100 parts by weight of the resin
containing, as a main component, a water-soluble monomer and having
autocatalysis (component A).
[0195] When the compounding amount of the organic filler is less
than 1 part by weight, the effect for enhancing the moldability of
the composition is small, whereas when it is more than 300 parts by
weight, it is difficult to disperse the filler uniformly, or there
may be a possibility that the strength and appearance as well as
moldability and heat resistance of the composition as a material
are deteriorated, and hence, such is not preferred.
[0196] It is preferred that the composition of the present
invention contains an inorganic filler. By containing an inorganic
filler, a composition having excellent mechanical properties, heat
resistance, and moldability can be obtained. As the inorganic
filler which is used in the present invention, a fibrous, platy, or
powdery filler which is used for reinforcing an ordinary
thermoplastic resin can be used.
[0197] Specifically, examples thereof include fibrous inorganic
fillers, such as carbon nanotubes, glass fibers, asbestos fibers,
carbon fibers, graphite fibers, metal fibers, potassium titanate
whiskers, aluminum borate whiskers, magnesium-based whiskers,
silicon-based whiskers, wollastonite, imogolite, sepiolite,
asbestos, slug fibers, zonolite, gypsum fibers, silica fibers,
silica-alumina fibers, zirconia fibers, boron nitride fibers,
silicon nitride fibers, boron fibers, etc.; and platy or
particulate inorganic fillers, such as stratiform silicates,
stratiform silicates exchanged with an organic onium ion, glass
flakes, non-swelling mica, graphite, metal foils, ceramic beads,
talc, clay, mica, sericite, zeolite, bentonite, dolomite, kaolin,
powdery silicic acid, feldspar powder, potassium titanate, Silas
balloon, calcium carbonate, magnesium carbonate, barium sulfate,
calcium oxide, aluminum oxide, titanium oxide, aluminum silicate,
silicon oxide, gypsum, novaculite, dosonite, carbon nanoparticles
including white clay fullerene or the like, etc.
[0198] Specific examples of the stratiform silicate include
smectite-based clay minerals, such as montmorillonite, beidellite,
nontronite, saponite, hectorite, sauconite, etc.; various clay
minerals, such as vermiculite, halocite, kanemite, kenyaite, etc.;
swelling micas, such as Li type fluorine taeniolite, Na type
fluorine taeniolite, Li type tetrasilicon fluorine mica, Na type
tetrasilicon fluorine mica, etc.; and the like. These may be
natural or synthetic. Of these, smectite-based clay minerals, such
as montmorillonite, hectorite, etc., and swelling synthetic micas,
such as Li type fluorine taeniolite, Na type tetrasilicon fluorine
mica, etc., are preferred.
[0199] Of these inorganic fillers, fibrous or platy inorganic
fillers are preferred, and glass fibers, wollastonite, aluminum
borate whiskers, potassium titanate whiskers, mica, kaolin, and
cation-exchanged stratiform silicates are especially preferred. An
aspect ratio of the fibrous filler is preferably 5 or more, more
preferably 10 or more, and still more preferably 20 or more.
[0200] Such a filler may be covered or bundled with a thermoplastic
resin, such as an ethylene/vinyl acetate copolymer, etc., or a
thermosetting resin, such as an epoxy resin, etc., or treated with
a coupling agent, such as aminosilane, epoxysilane, etc.
[0201] A compounding amount of the inorganic filler is preferably
0.1 to 200 parts by weight, more preferably 0.5 to 100 parts by
weight, still more preferably 1 to 50 parts by weight, especially
preferably 1 to 30 parts by weight, and most preferably 1 to 20
parts by weight based on 100 parts by weight of the resin
containing, as a main component, a water-soluble monomer and having
autocatalysis (component A).
<Release Agent>
[0202] The resin composition of the present invention can contain a
release agent. As the release agent which is used in the present
invention, those which are used for ordinary thermoplastic resins
can be used.
[0203] Specifically, examples of the release agent may include
fatty acids, fatty acid metal salts, hydroxy fatty acids,
paraffins, low-molecular weight polyolefins, fatty acid amides,
alkylene bis-fatty acid amides, aliphatic ketones, fatty acid
partially saponified esters, fatty acid lower alcohol esters, fatty
acid polyhydric alcohol esters, fatty acid polyglycol esters,
modified silicones, and the like. By compounding such a release
agent, a polylactic acid molded article having excellent mechanical
properties, moldability, and heat resistance can be obtained.
[0204] As the fatty acid, those having 6 to 40 carbon atoms are
preferred, and specifically, examples thereof include oleic acid,
stearic acid, lauric acid, hydroxystearic acid, behenic acid,
arachidonic acid, linoleic acid, linolenic acid, ricinoleic acid,
palmitic acid, montanic acid, and a mixture thereof, and the like.
As the fatty acid metal salt, alkali metal salts or alkaline earth
metal salts of a fatty acid having 6 to 40 carbon atoms are
preferred, and specifically, examples thereof include calcium
stearate, sodium montanate, calcium montanate, and the like.
[0205] Examples of the hydroxy fatty acid include
1,2-hydroxystearic acid and the like. As the paraffin, those having
18 carbon atoms or more are preferred, and examples thereof include
liquid paraffin, natural paraffin, a microcrystalline wax,
petrolactam, and the like.
[0206] As the low-molecular weight polyolefin, for example, those
having a molecular weight of 5,000 or less are preferred, and
specifically, examples thereof include a polyethylene wax, a maleic
acid modified polyethylene wax, an oxide type polyethylene wax, a
chlorinated polyethylene wax, a polypropylene wax, and the like. As
the fatty acid amide, those having 6 or more carbon atoms are
preferred, and specifically, examples thereof include oleic acid
amide, erucic acid amide, behenic acid amide, and the like.
[0207] As the alkylene bis-fatty acid amide, those having 6 or more
carbon atoms are preferred, and specifically, examples thereof
include methylene bis-stearic acid amide, ethylene bis-stearic acid
amide, N,N-bis(2-hydroxyethyl)stearic acid amide, and the like. As
the aliphatic ketone, those having 6 or more carbon atoms are
preferred, and examples thereof include higher aliphatic ketones
and the like.
[0208] Examples of the fatty acid partially saponified ester
include montanic acid partially saponified esters and the like.
Examples of the fatty acid lower alcohol ester include stearic acid
esters, oleic acid esters, linoleic acid esters, linolenic acid
esters, adipic acid esters, behenic acid esters, arachidonic acid
esters, montanic acid esters, isostearic acid esters, and the
like.
[0209] Examples of the fatty acid polyhydric alcohol ester include
glycerol tristearate, glycerol distearate, glycerol monostearate,
pentaerythritoltetrastearate, pentaerythritol tristearate,
pentaerythritol distearate, pentaerythritol monostearate,
pentaerythritol adipate stearate, sorbitan monobehenate, and the
like. Examples of the fatty acid polyglycol ester include
polyethylene glycol fatty acid esters, polypropylene glycol fatty
acid esters, and the like.
[0210] Examples of the modified silicone include polyether modified
silicones, higher fatty acid alkoxy modified silicones, higher
fatty acid-containing silicones, higher fatty acid ester modified
silicones, methacrylic modified silicones, fluorine modified
silicone, and the like.
[0211] Of these, fatty acids, fatty acid metal salts, hydroxy fatty
acids, fatty acid esters, fatty acid partially saponified esters,
paraffins, low-molecular weight polyolefins, fatty acid amides, and
alkylene-bis fatty acid amides are preferred, and fatty acid
partially saponified esters and alkylene-bis fatty acid amides are
more preferred. Above all, montanic acid esters, montanic acid
partially saponified esters, polyethylene waxes, oxidized
polyethylene waxes, sorbitan fatty acid esters, erucic acid amide,
and ethylene bis-stearic acid amide are still more preferred, and
montanic acid partially saponified esters and ethylene bis-stearic
acid amide are especially preferred.
[0212] The release agent may be used alone, or may be used in
combination of two or more kinds thereof. A content of the release
agent is preferably 0.01 to 3 parts by weight, and more preferably
0.03 to 2 parts by weight based on 100 parts by weight of the resin
containing, as a main component, a water-soluble monomer and having
autocatalysis (component A).
<Antistatic Agent>
[0213] The resin composition of the present invention can contain
an antistatic agent. Examples of the antistatic agent include
quaternary ammonium salt-based compounds, sulfonate-based
compounds, and alkyl phosphate-based compounds, such as
(.beta.-lauramidepropionyl)trimethylammonium sulfate, sodium
dodecylbenzenesulfonate, etc., and the like.
[0214] In the present invention, the antistatic agent may be used
alone, or may be used in combination of two or more kinds thereof.
A content of the antistatic agent is preferably 0.05 to 5 parts by
weight, and more preferably 0.1 to 5 parts by weight based on 100
parts by weight of the resin containing, as a main component, a
water-soluble monomer and having autocatalysis (component A).
<Plasticizer>
[0215] The resin composition of the present invention can contain a
plasticizer. As the plasticizer, those which are generally known
can be used. Examples thereof include polyester-based plasticizers,
glycerin-based plasticizers, multivalent carboxylic acid
ester-based plasticizers, phosphoric acid ester-based plasticizers,
polyalkylene glycol-based plasticizers, epoxy-based plasticizers,
and the like.
[0216] Examples of the polyester-based plasticizer include
polyesters composed of an acid component, such as adipic acid,
sebacic acid, terephthalic acid, isophthalic acid,
naphthalenedicarboxylic acid, diphenyldicarboxylic acid, etc., and
a diol component, such as ethylene glycol, propylene glycol,
1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol,
diethylene glycol, etc.; polyesters composed of a hydroxycarboxylic
acid, such as polycaprolactone, etc.; and the like. The ends of
such a polyester may be sealed with a monofunctional carboxylic
acid or a monofunctional alcohol.
[0217] Examples of the glycerin-based plasticizer include glycerin
monostearate, glycerin distearate, glycerin monoacetomonolaurate,
glycerin monoacetomonostearate, glycerin diacetomonooleate,
glycerin monoacetomonomontanate, and the like.
[0218] Examples of the multivalent carboxylic acid-based
plasticizer include phthalic acid esters, such as dimethyl
phthalate, diethyl phthalate, dibutyl phthalate, diheptyl
phthalate, dibenzyl phthalate, butylbenzyl phthalate, etc.;
trimellitic acid esters, such as tributyl trimellitate, trioctyl
trimellitate, trihexyl trimellitate, etc.; adipic acid esters, such
as isodecyl adipate, n-decyl-n-octyl adipate, etc.; citric acid
esters, such as tributyl acetylcitrate, etc.; azelaic acid esters,
such as bis(2-ethylhexyl) azelate, etc.; and sebacic acid esters,
such as dibutyl sebacate, bis(2-ethylhexyl) sebacate, etc.
[0219] Examples of the phosphoric acid ester-based plasticizer
include tributyl phosphate, tris(2-ethylhexyl) phosphate, trioctyl
phosphate, triphenyl phosphate, tricresyl phosphate,
diphenyl-2-ethylhexyl phosphate, and the like.
[0220] Examples of the polyalkylene glycol-based plasticizer
include polyalkylene glycols, such as polyethylene glycol,
polypropylene glycol, polytetramethylene glycol, poly(ethylene
oxide-propylene oxide) block and/or random copolymers, ethylene
oxide addition polymers of a bisphenol, tetrahydrofuran addition
polymers of a bisphenol, etc.; terminal-sealing compounds, such as
terminal epoxy modified compounds, terminal ester modified
compounds, and terminal ether modified compounds of these
polyalkylene glycols, etc.; and the like.
[0221] Examples of the epoxy-based plasticizer include epoxy
triglyceride composed of an alkyl epoxystearate and soybean oil,
and an epoxy resin obtained from bisphenol A and epichlorohydrin as
raw materials.
[0222] Specific examples of other plasticizer include benzoic acid
esters of an aliphatic polyol, such as neopentyl glycol dibenzoate,
diethylene glycol dibenzoate, triethylene
glycol-bis(2-ethylbutyrate), etc.; fatty acid amides, such as
stearic acid amide, etc.; fatty acid esters, such as butyl oleate,
etc.; oxyacid esters, such as methyl acetyl ricinoleate, butyl
acetyl ricinoleate, etc.; pentaerythritols; fatty acid esters of a
pentaerythritol; various sorbitols; polyacrylic acid esters;
silicone oil; paraffins; and the like.
[0223] As the plasticizer, at least one member selected from
polyester-based plasticizers, polyalkylene-based plasticizers,
glycerin-based plasticizers, pentaerythritols, and fatty acid
esters of a pentaerythritol can be especially preferably used, and
the plasticizer may be used alone or can also be used in
combination of two or more kinds thereof.
[0224] A content of the plasticizer is preferably 0.01 to 30 parts
by weight, more preferably 0.05 to 20 parts by weight, and still
more preferably 0.1 to 10 parts by weight based on 100 parts by
weight of the resin containing, as a main component, a
water-soluble monomer and having autocatalysis (component A). In
the present invention, the crystallization nucleating agent and the
plasticizer may be used independently, and it is more preferred to
use a combination of the both.
<Impact Resistance-Improving Agent>
[0225] The resin composition of the present invention can contain
an impact resistance-improving agent. The impact
resistance-improving agent is a material which can be used for
improving the impact resistance of a thermoplastic resin and is not
particularly limited. For example, at least one member selected
among the following impact resistance-improving agents.
[0226] Specific examples of the impact resistance-improving agent
include an ethylene-propylene copolymer, an
ethylene-propylene-non-conjugated diene copolymer, an
ethylene-butene-1 copolymer, various acrylic rubber, an
ethylene-acrylic acid copolymer and an alkali metal salt thereof
(so-called "ionomer"), an ethylene-glycidyl (meth)acrylate
copolymer, an ethylene-acrylic acid ester copolymer (for example,
an ethylene-ethyl acrylate copolymer and an ethylene-butyl acrylate
copolymer), a modified ethylene-propylene copolymer, a diene rubber
(for example, polybutadiene, polyisoprene, and polychloroprene), a
diene-vinyl copolymer (for example, a styrene-butadiene random
copolymer, a styrene-butadiene block copolymer, a
styrene-butadiene-styrene block copolymer, a styrene-isoprene
random copolymer, a styrene-isoprene block copolymer, a
styrene-isoprene-styrene block copolymer, a polybutadiene-styrene
graft copolymer, and a butadiene-acrylonitrile copolymer),
polyisobutylene, a copolymer of isobutylene and butadiene or
isoprene, a natural rubber, a Thiokol rubber, a polysulfide rubber,
a polyurethane rubber, a polyether rubber, an epichlorohydrin
rubber, and the like.
[0227] Furthermore, impact resistance-improving agents having a
degree of crosslinking of every sort and various micro-structures,
for example, a cis-structure and a trans-structure, and core-shell
type multilayer polymers, each composed of a core layer and at
least one shell layer covering the core layer, or having adjacent
layers made of different polymers, can also be used.
[0228] Furthermore, the various (co)polymers specifically
exemplified above may be either a random copolymer or a block
copolymer, and these can be used as the impact resistance-improving
agent of the present invention.
[0229] A content of the impact resistance-improving agent is
preferably 1 to 30 parts by weight, more preferably 5 to 20 parts
by weight, and still more preferably 10 to 20 parts by weight based
on 100 parts by weight of the resin containing, as a main
component, a water-soluble monomer and having autocatalysis
(component A).
<Others>
[0230] The resin composition of the present invention may contain a
thermosetting resin, such as a phenol resin, a melamine resin, a
thermosetting polyester resin, a silicone resin, an epoxy resin,
etc., within the range where the gist of the present invention is
not deviated.
[0231] The resin composition of the present invention may also
contain a flame retardant, such as a bromine-based material, a
phosphorus-based material, a silicone-based material, an antimony
compound, etc., within the range where the gist of the present
invention is not deviated.
[0232] The resin composition may also contain a colorant including
an organic or inorganic dye or pigment, for example, an oxide, such
as titanium dioxide, etc., a hydroxide, such as alumina white,
etc., a sulfide, such as zinc sulfide, etc., a ferrocyanide
compound, such as iron blue, etc., a chromate, such as zinc
chromate, etc., a sulfate, such as barium sulfate, etc., a
carbonate, such as calcium carbonate, etc., a silicate, such as
ultramarine blue, etc., a phosphate, such as manganese violet,
etc., carbon, such as carbon black, etc., a metal colorant, such as
a bronze powder, an aluminum powder, etc., and the like.
[0233] The resin composition may also contain an additive including
a condensation polycyclic colorant, for example, a nitroso-based
condensation polycyclic colorant, such as Naphthol Green B, etc., a
nitro-based condensation polycyclic colorant, such as Naphthol
Yellow S, etc., an azo-based condensation polycyclic colorant, such
as Naphthol Red, Chromophthal Yellow, etc., a phthalocyanine-based
condensation polycyclic colorant, such as Phthalocyanine Blue, Fast
Sky Blue, etc., Indanthrene Blue, and the like, and a
slidability-improving agent, such as graphite, a fluorine resin,
etc. These additives may be used alone or can also be used in
combination of two or more kinds thereof.
<Molded Article>
[0234] A molded article made of the resin composition of the
present invention can be formed by means of injection molding,
extrusion molding, vacuum or pressure molding, blow molding, or the
like. Examples of the molded article include a pellet, a fiber, a
textile, a fiber structure, a film, a sheet, a sheet nonwoven
fabric, and the like.
[0235] The melt molding method of the pellet made of the resin
composition of the present invention is not limited at all, and
pellets produced by a known pellet production method can be
suitably used.
[0236] That is, though methods, such as a method in which the resin
composition extruded into a strand or plate is cut in air or water
after the resin is completely solidified, or while it is still
molten and not completely solidified, etc., are conventionally
known, all of those methods can be suitably applied in the present
invention.
[0237] For the injection molding, molding conditions may be
properly set according to the type of the resin containing, as a
main component, a water-soluble monomer and having autocatalysis
(component A). However, from the viewpoints of promoting the
crystallization and the molding cycle of a molded article at the
time of injection molding, for example, when the resin containing,
as a main component, a water-soluble monomer and having
autocatalysis (component A) is polylactic acid, a die temperature
is preferably 30.degree. C. or higher, more preferably 60.degree.
C. or higher, and still more preferably 70.degree. C. or higher.
However, in order to prevent the deformation of a molded article,
the die temperature is preferably 140.degree. C. or lower, more
preferably 120.degree. C. or lower, and still more preferably
110.degree. C. or lower.
[0238] Examples of such a molded article include various housings,
electric and electronic parts, such as toothed wheels, gears, etc.,
construction members, civil engineering members, agricultural
materials, automobile parts (interior and exterior parts, etc.),
parts for daily use, and the like.
[0239] As for the fiber and the fiber structure made of the resin
composition of the present invention, materials obtained by
ordinary melt spinning and post-processing after that can be
suitably used.
[0240] That is, the resin containing, as a main component, a
water-soluble monomer and having autocatalysis (component A) is
melted by an extruder type or pressure melter type melt extruder,
weighed by a gear pump, filtered within a pack, and then discharged
as a monofilament or a multifilament, or the like from nozzles
provided in a spinneret.
[0241] The shape and number of spinnerets are not particularly
limited, and all of a circular type, an atypical type, a solid
type, a hollow type, and the like can be adopted. The discharged
yarn is immediately cooled and solidified, and thereafter, the
resultant is bundled, applied with a lubricant, and wound up.
Although a winding rate is not particularly limited, it is
preferably in the range of 100 m/min to 5,000 m/min because a
stereocomplex crystal is easily formed when the resin containing,
as a main component, a water-soluble monomer and having
autocatalysis (component A) is stereocomplex polylactic acid.
[0242] Although the wound unstretched yarn can be used as it is, it
can also be stretched and used.
[0243] In the case of using the yarn in an unstretched state, it is
preferred to perform a heat treatment at a temperature equal to or
higher than the glass transition temperature (Tg) and lower than
the melting point of the resin containing, as a main component, a
water-soluble monomer and having autocatalysis (component A) after
spinning and before winding up. Arbitrary means, such as a contact
type heater, a non-contact hot plate, etc., can be adopted for the
heat treatment besides a hot roller.
[0244] In the case of performing stretching, a spinning step and a
stretching step are not always needed to be separated from each
other, and a direct spinning/stretching method in which after
spinning, stretching is subsequently performed without once winding
up the spun yarn may be adopted.
[0245] Stretching may be performed in one stage or two or more
multiple stages, and from the viewpoint of fabricating a
high-strength fiber, a draw ratio is preferably 3 times or more,
and more preferably 4 times or more. The draw ratio is preferably
selected from 3 to 10 times. However, when the draw ratio is too
high, the fiber is devitrified and whitened, whereby the strength
of the fiber is lowered, and rupture elongation becomes too small
for a fiber application, and hence, such is not preferred.
[0246] As for a preheating method for stretching, besides
temperature elevation of a roll, a plate-like or pin-like contact
heater, a non-contact hot plate, a heat medium bath, and the like
may be adopted. However, commonly used means may be adopted.
[0247] It is preferred that after spinning, the heat treatment is
subsequently performed at a temperature equal to or higher than the
glass transition temperature (Tg) and lower than the melting point
of the resin containing, as a main component, a water-soluble
monomer and having autocatalysis (component A) before winding
up.
[0248] Besides a hot roller, arbitrary means, such as a contact
heater, a non-contact hot plate, etc., can be adopted for the heat
treatment.
[0249] For example, when the resin containing, as a main component,
a water-soluble monomer and having autocatalysis (component A) is
polylactic acid, a stretching temperature is selected within the
range of the glass transition temperature (Tg) to 170.degree. C.,
preferably 60.degree. C. to 140.degree. C., and especially
preferably 70.degree. C. to 130.degree. C.
[0250] The fiber obtained from the resin composition of the present
invention may be a short fiber. In the case of producing a short
fiber, in addition to a stretching method of a long fiber, a step
of cutting in a prescribed fiber length according to an application
by using a rotary cutter or the like is added, and in the case
where crimping is further needed, a step of imparting crimps by
using a forced crimper or the like is added between a fixed-length
heat treatment and a relaxation heat treatment. On that occasion,
in order to increase crimp-imparting properties, preheating can be
performed by using steam, an electric heater, or the like before
the crimper.
[0251] When the resin containing, as a main component, a
water-soluble monomer and having autocatalysis (component A) is
stereocomplex polylactic acid, a polylactic acid fiber having a
high stereocomplex crystallization degree (S), low heat shrinkage,
and a strength of 3.5 cN/dTex or more can also be obtained by heat
setting at 170 to 220.degree. C. under a tension after
stretching.
[0252] Fibers and fiber structures obtained from the resin
composition of the present invention may be used as fibers made of
the resin composition alone or can be mixed with another type of
fibers. Examples of the mixture include not only various
combinations with a fiber structure made of another type of fibers
but also a combined filament yarn with another type of fibers, a
composite false twisted yarn, a blended yarn, a long/short
composite yarn, a fluid processed yarn, a covering yarn, a twisted
yarn, a combined weave, a combined knitting, a pile fabric, a
cotton mixing/wadding, a long fiber or short fiber mixed nonwoven
fabric, a felt, and the like. When another type of fibers are used
together, a mixing ratio of the fibers is selected within the range
of preferably 1% by weight or more, more preferably 10% by weight
or more, and still more preferably 30% by weight in order to
exhibit the characteristic features of the resin composition.
[0253] Examples of the another type of fibers to be mixed include
cellulose fibers, such as cotton, hemp, rayon, and tencel fibers,
etc.; wool, silk, acetate, polyester, nylon, acrylic, vinylon,
polyolefin, and polyurethane fibers; and the like.
[0254] The film or sheet obtained from the resin composition of the
present invention can be molded by a conventionally known method.
For example, in the film or sheet, molding techniques, such as
extrusion molding, cast molding, etc., can be adopted. That is,
molding can be performed by extruding an unstretched film by using
an extruder having a T die or circular die or the like installed
therein, or the like and further stretching and heating. At this
time, the unstretched film can be directly put into practical use
as a sheet. In forming a film, not only a material obtained by melt
kneading the resin composition and the above-described various
components in advance can be used, but also these components can be
molded through melt kneading at the time of extrusion molding. An
unstretched film having few surface defects can be obtained by
compounding an electrostatic adhesive, such as a quaternary
phosphonium sulfonate, etc. with the molten resin at the time of
extruding an unstretched film.
[0255] An unstretched film can also be cast molded by dissolving
the resin composition and the additive components in a common
solvent, for example, chloroform, methylene dichloride, or the
like, and casting the resulting solution, followed by drying for
solidification. The unstretched film can be subjected to vertical
uniaxial stretching in a mechanical flow direction or horizontal
uniaxial stretching in a direction orthogonal to the mechanical
flow direction. A biaxially stretched film can be produced by
performing a sequential biaxial stretching method of roller
stretching and tenter stretching, a simultaneous biaxial stretching
method by tenter stretching, a biaxial stretching method by tubular
stretching, or other means. Furthermore, the film is generally heat
set after stretching for the purpose of suppressing its heat
shrinkage or the like. If desired, the thus-obtained stretched film
may also be subjected to a surface activation treatment, such as a
plasma treatment, an amine treatment, or a corona treatment, in
accordance with a conventionally known method.
[0256] The film or sheet of the present invention may be used alone
or in combination with another type of a film or sheet. As the
combination form, not only various combinations with a film or
sheet made of another material, for example, in a form of a stack,
a laminate, and the like, but also combinations with another form,
such as an injection molded article, a fiber structure, etc. may be
exemplified.
[0257] The second invention of the present application is hereunder
explained in detail.
[0258] The resin composition of the present invention is a resin
composition including an aliphatic polyester containing, as a main
component, a water-soluble monomer (component C) and a hydrolysis
regulator having reactivity with an acidic group in a 15%
hydrochloric acid aqueous solution at 100.degree. C. of 30% or more
(component D), the resin composition satisfying any one of the
following J1 to J2:
J1: In the 15% hydrochloric acid aqueous solution at 100.degree.
C., after 6 hours, a weight average molecular weight retention rate
of the resin composition is 50% or more, and after 24 hours, a
weight of a water-insoluble matter of the resin composition is 50%
or less; and J2: In the 15% hydrochloric acid aqueous solution at
120.degree. C., after 1 hour, a weight average molecular weight
retention rate of the resin composition is 50% or more, and after
24 hours, a weight of a water-insoluble matter of the resin
composition is 50% or less.
<Aliphatic Polyester Containing, as a Main Component, a
Water-Soluble Monomer (Component C)>
[0259] In the present invention, in the aliphatic polyester
containing, as a main component, a water-soluble monomer (component
C), the monomer generated by decomposition exhibits solubility in
water, and the resin in which an acidic group generated by
decomposition has autocatalysis, or at least a part of ends of the
resin is sealed by the hydrolysis regulator (component D).
[0260] The term "water-soluble" referred to herein means that the
solubility in water at 25.degree. C. is 0.1 g/L or more. From the
viewpoint that the resin composition to be used does not remain
after decomposition, the solubility in water of the water-soluble
monomer is preferably 1 g/L or more, more preferably 3 g/L or more,
and still more preferably 5 g/L or more.
[0261] The "main component" means that it occupies 90 mol % or more
of the constituent components. A proportion of the main component
is preferably 95 to 100 mol %, and more preferably 98 to 100 mol
%.
[0262] Examples of the component C include known aliphatic
polyesters.
[0263] Examples of the aliphatic polyester include polymers
containing an aliphatic hydroxycarboxylic acid as a main
constituent component, polymers obtained by polycondensing an
aliphatic multivalent carboxylic acid or an ester forming
derivative and an aliphatic polyhydric alcohol as main components,
and copolymers thereof.
[0264] The polymer containing an aliphatic hydroxycarboxylic acid
as a main constituent component and the polymer containing an
aliphatic multivalent carboxylic acid and an aliphatic polyhydric
alcohol as main constituent components are the same as in the
description of the component A in the foregoing first invention of
the present application.
<Hydrolysis Regulator (Component D)>
[0265] In the present invention, the hydrolysis regulator
(component D) is an agent for regulating hydrolysis properties by
sealing an end group of the aliphatic polyester containing, as a
main component, a water-soluble monomer (component C) and an acidic
group generated by decomposition. That is, the hydrolysis regulator
(component D) is an agent having an effect for inhibiting the
autocatalysis of the aliphatic polyester containing, as a main
component, a water-soluble monomer (component C) to delay the
hydrolysis.
[0266] As the acidic group, at least one member selected from the
group consisting of a carboxyl group, a sulfonic acid group, a
sulfinic acid group, a phosphonic acid group, and a phosphinic acid
group is exemplified. In the present invention, a carboxyl group is
especially exemplified.
[0267] Since a condition to be used is one in hot water under a
chemically severe condition, such as an acidic or basic condition,
etc., the hydrolysis regulator (component C) has reactivity with an
acidic group in a 15% hydrochloric acid aqueous solution at
100.degree. C. of 30% or more.
[0268] The reactivity with an acidic group in a 15% hydrochloric
acid aqueous solution at 100.degree. C. as referred to herein is,
for example, a value obtained by evaluating a carboxyl group
concentration regarding a resin composition after treating the
resin composition in 15% hydrochloric acid for 3 hours, the resin
composition being obtained by adding 5 parts by weight of the
hydrolysis regulator to 95 parts by weight of polylactic acid for
evaluation, followed by melt kneading under a nitrogen atmosphere
at a resin temperature of 200.degree. C. and at a rotation rate of
30 rpm for 2 minutes by using a Labo Plasto mill (manufactured by
Toyo Seiki Seisaku-Sho, Ltd.), and using a carboxyl group
concentration after similarly treating polylactic acid for
evaluation in a 15% hydrochloric acid aqueous solution at
100.degree. C. for 3 hours, the value being given according to the
following equation (vi).
Reactivity (%)=[{(Carboxyl group concentration of polylactic acid
for evaluation after treatment in 15% hydrochloric acid aqueous
solution at 100.degree. C. for 3 hours)-(Carboxyl group
concentration of resin composition after treatment in 15%
hydrochloric acid aqueous solution at 100.degree. C. for 3
hours)}/(Carboxyl group concentration of polylactic acid for
evaluation after treatment in 15% hydrochloric acid aqueous
solution at 100.degree. C. for 3 hours)].times.100 (vi)
[0269] Here, the treatment in a 15% hydrochloric acid aqueous
solution at 100.degree. C. was performed in the following manner.
That is, a glass-made screw-capped test tube (manufactured by
Maruemu Corporation, NN-13, capacity: about 5 mL) was charged with
150 mg of a resin composition (one having been previously
crystallized by a heat treatment at 110.degree. C. for 10 minutes
and having a chip-like shape of 0.5 mm to 2 mm in each side) and 3
mL of a 15% hydrochloric acid aqueous solution (one prepared by
diluting hydrochloric acid (manufactured by Wako Pure Chemical
Industries, Ltd., Special grade, 35 to 37%) with distilled water),
hermetically sealed, and allowed to stand for 3 hours within a hot
air dryer (manufactured by Toyo Seiki Seisaku-Sho, Ltd., FC-410)
which had been kept at 100.degree. C. in advance. Thereafter, the
test tube was taken out and cooled in a hermetically sealed state
to ordinary temperature (25.degree. C.) by means of water cooling.
Thereafter, the sample obtained after filtration was washed 5 times
with 5 mL of an acetone/water (70/30) mixed liquid and dried, and
then, the carboxyl group was measured. The polylactic acid for
evaluation was treated in the same manner.
[0270] The polylactic acid for evaluation is preferably one having
a weight average molecular weight of 120,000 to 200,000 and a
carboxyl group concentration of 10 to 30 equivalents/ton. As such
polylactic acid, polylactic acid "NW3001D", manufactured by
NatureWorks LLC (MW: 150,000, carboxyl group concentration: 24.1
equivalents/ton) and the like can be suitably used. Besides, the
reactivity with an acidic group may be given by the same
evaluation.
[0271] In the case of evaluating a stable agent for the reactivity,
an effect for controlling an increase of the carboxyl group
concentration of the resin composition is small. In the case of
using such an agent in hot water under a chemically severe
condition, such as an acidic or basic condition, etc., the ability
for sealing the target acidic group is not much exhibited, and
therefore, the effect for inhibiting the decomposition of the
aliphatic polyester containing, as a main component, a
water-soluble monomer (component C) is low.
[0272] In view of the foregoing, the reactivity with an acidic
group in the 15% hydrochloric acid aqueous solution at 100.degree.
C. is preferably 30% or more, more preferably 40% or more, and
especially preferably 50% or more. That is, when the reactivity is
50% or more, namely the reactivity with an acidic group in the 15%
hydrochloric acid aqueous solution is high, the reaction with the
acidic group can be efficiently performed under the condition of
the instant application.
[0273] Examples of the hydrolysis regulator (component D) include
addition reaction type compounds, such as carbodiimide compounds,
isocyanate compounds, epoxy compounds, oxazoline compounds, oxazine
compounds, aziridine compounds, etc. These compounds can also be
used in combination of two or more thereof. From the viewpoints of
reactivity with an acidic group, carbodiimide compounds and epoxy
compounds are preferably exemplified.
[0274] As the carbodiimide compound, all of monofunctional
carbodiimide compounds and bifunctional or polyfunctional
carbodiimide compounds can be used, and a compound having a basic
structure represented by the following general formula (I), (II).
or (III) can be exemplified.
R--N.dbd.C.dbd.N--R' (I)
[0275] (In the formula, each of R and R' is independently an
aliphatic group having 1 to 20 carbon atoms, an alicyclic group
having 3 to 20 carbon atoms, an aromatic group having 5 to 15
carbon atoms, or a combination thereof, and may contain a hetero
atom; and R and R' may be bonded to each other to form a cyclic
structure, and may form two or more cyclic structures through a
Spiro structure or the like.)
##STR00011##
[0276] (In the formula, each R'' is independently an aliphatic
group having 1 to 20 carbon atoms, an alicyclic group having 3 to
20 carbon atoms, an aromatic group having 5 to 15 carbon atoms, or
a combination thereof, and may contain a hetero atom; and n is an
integer of 2 to 1,000.)
##STR00012##
[0277] (In the formula, Q is a divalent to tetravalent bonding
group that is an aliphatic group, an alicyclic group, an aromatic
group, or a combination thereof and may contain a hetero atom or a
substituent.)
[0278] From the viewpoint of keeping the molecular weight,
bifunctional or polyfunctional carbodiimide compounds are
preferred. Examples thereof include carbodiimide compounds
represented by the following formulae (6) and (7).
##STR00013##
[0279] (In the formula, X is a tetravalent group represented by the
following formula (6-1); and each of Ar.sup.1 to Ar.sup.4 is
independently an orthophenylene group or a 1,2-naphthalene-diyl
group, each of which may be substituted with a substituent.)
##STR00014##
[0280] (In the formula, each r is independently an aliphatic group
having 1 to 20 carbon atoms, an alicyclic group having 3 to 20
carbon atoms, an aromatic group having 5 to 15 carbon atoms, or a
combination thereof and may contain a hetero atom; and m is an
integer of 2 to 1,000.)
[0281] Specific examples of such an aromatic compound include a
cyclic carbodiimide represented by the following formula (8),
polymers composed of 4,4'-dicyclohexylmethane carbodiimide as a
monomer, polymers composed of tetramethylxylylene carbodiimide as a
monomer, and derivatives thereof, and the like.
##STR00015##
[0282] As the epoxy compound, all of monofunctional epoxy compounds
and bifunctional or polyfunctional epoxy compounds can be used, and
examples thereof include alicyclic epoxy compounds, epoxidized
vegetable oils obtained by epoxidizing a vegetable oil, epoxy
compounds having a glycidyl group, and the like.
[0283] From the viewpoint of keeping the molecular weight,
bifunctional or polyfunctional epoxy compounds are preferred.
[0284] Examples of such an epoxy compound include alicyclic epoxy
compounds, such as
3,4-epoxycyclohexenylmethyl-3',4'-epoxycyclohexene carboxylate,
.epsilon.-caprolactone-modified
3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexane carboxylate,
epoxidized 3-cyclohexene-1,2-dicarboxylic acid
bis(3-cyclohexenylmethyl)-modified .epsilon.-caprolactone,
epoxidized butanetetracarboxylic acid
tetrakis-(3-cyclohexenylmethyl)-modified .epsilon.-caprolactone,
etc., diglycidyl ether compounds, and the like. Above all,
3,4-epoxycyclohexenylmethyl-3',4'-epoxycyclohexene carboxylate can
be suitably used.
<Resin Composition>
[0285] The resin composition of the second invention of the present
application satisfies any one of the following J1 to J2:
J1: In the 15% hydrochloric acid aqueous solution at 100.degree.
C., after 6 hours, a weight average molecular weight retention rate
of the resin composition is 50% or more, and after 24 hours, a
weight of a water-insoluble matter of the resin composition is 50%
or less; and J2: In the 15% hydrochloric acid aqueous solution at
120.degree. C., after 1 hour, a weight average molecular weight
retention rate of the resin composition is 50% or more, and after
24 hours, a weight of a water-insoluble matter of the resin
composition is 50% or less.
[0286] In order that the resin composition of the present invention
may exhibit the desired performance, it is important to control the
resin composition so as to be quickly decomposed after keeping the
weight and shape of the resin in hot water under a chemically
severe condition, such as an acidic or basic condition, etc., for a
fixed period of time.
[0287] Although the fixed period of time is determined according to
an application, it is preferably any of 10 minutes to 12 hours.
From the viewpoint of exhibiting the desired performance, the fixed
period of time is more preferably any of 30 minutes to 10 hours,
and still more preferably any of 30 minutes to 8 hours.
[0288] As for the matter of keeping the weight and shape of the
resin, it is preferred that the weight of the water-insoluble
matter of the resin composition is 50% or more; and that the amount
of volume change expressing the shape is 50% or less. For example,
even when the weight of the water-insoluble matter of the resin
composition is 50% or more, if it is in the completely hydrolyzed
state, it may not be said that the weight and shape of the resin
are kept. From the viewpoint of exhibiting the desired performance,
the weight of the water-insoluble matter of the resin composition
is more preferably 60% or more, and still more preferably 70% or
more. The amount of volume change expressing the shape is more
preferably 40% or less, and still more preferably 30% or less.
[0289] The weight and shape of the resin largely relies upon the
weight average molecular weight of the resin composition. That is,
the resin composition in which decomposition of the resin proceeds,
and the weight average molecular weight becomes low cannot keep the
weight and shape of the resin, and the desired performance cannot
be exhibited in the instant application.
[0290] Although it is needed to not only keep the weight and shape
but also keep the mechanical physical properties in order to
effectively exhibit the function in the instant application, it is
important to keep the weight average molecular weight from these
viewpoints.
[0291] In consequence, it is important to keep the weight average
molecular weight in hot water under a chemically severe condition,
such as an acidic or basic condition, etc., for a fixed period of
time, and the weight average molecular weight retention rate of the
resin composition of the present invention is preferably 50% or
more. When the weight average molecular weight retention rate is
lower than 50%, there may be the case where the mechanical physical
properties are lowered, and furthermore, changes in the weight and
shape become remarkable. For that reason, from the viewpoint of
exhibiting the desired performance, the weight average molecular
weight retention rate is more preferably 60% or more, and still
more preferably 70% or more.
[0292] Here, the weight of the water-insoluble matter and the
weight average molecular weight retention rate of the resin are,
for example, values given by the following evaluations.
[0293] A glass-made screw-capped test tube (manufactured by Maruemu
Corporation, NN-13, capacity: about 5 mL) is charged with 50 mg of
a resin composition (one having been previously crystallized by a
heat treatment at 110.degree. C. for 10 minutes and having a
chip-like shape of 0.5 mm to 2 mm in each side) and 1 mL of a 15%
hydrochloric acid aqueous solution and hermetically sealed.
[0294] The 15% hydrochloric acid aqueous solution is prepared by
diluting hydrochloric acid (manufactured by Wako Pure Chemical
Industries, Ltd., Special grade, 35 to 37%) with distilled water
and subjected to neutralization titration with a sodium hydroxide
aqueous solution standard liquid, thereby confirming the
concentration.
[0295] In the case where the test temperature is 100.degree. C. or
lower, the above-described test tube is allowed to stand within a
hot air dryer (manufactured by Toyo Seiki Seisaku-Sho, Ltd.,
FC-410) having been kept at a prescribed temperature in advance.
After elapsing a prescribed time, the test tube is taken out and
cooled to ordinary temperature (25.degree. C.) in a hermetically
sealed state of the test tube by means of water cooling.
[0296] In the case where the test temperature is higher than
100.degree. C. and 130.degree. C. or lower, the above-described
test tube is allowed to stand within a pressure cooker
(manufactured by Espec Corporation, HAS Chamber EHS-221M). After
the temperature within the pressure cooker reaches the test
temperature, and then a prescribed time elapses, the temperature
decrease is commenced. After 10 minutes, the test tube is taken out
from the pressure cooker and cooled to ordinary temperature
(25.degree. C.) in a hermetically sealed state of the test tube by
means of water cooling.
[0297] After cooling the test tube to ordinary temperature
(25.degree. C.), the test tube is opened, the resin composition in
the interior is filtered using a glass filter (manufactured by
Sibata Scientific Technology Ltd., 3GP100, pore size: 40 to 100
.mu.m), and the resin composition remaining on the glass filter is
washed with a large amount of distilled water. The washed resin
composition is dried at ordinary temperature (25.degree. C.) under
a vacuum of 133.3 Pa or less for 1 hour, and thereafter, the weight
of the resin composition is measured. The weight of the
water-insoluble matter is calculated according to the following
equation (vii).
Weight of water-insoluble matter (%)=[(Weight of resin composition
recovered by filtration after decomposition test)/(Weight of resin
composition before decomposition test)].times.100 (vii)
[0298] With respect to the resin composition after the
decomposition test, the weight average molecular weight (Mw) is
measured by means of gel permeation chromatography (GPC), and its
value is designated as Mw1. Mw of the resin composition before the
above-described decomposition test is measured by means of GPC, and
its value is designated as Mw0. The weight average molecular weight
retention rate is calculated according to the following equation
(viii)
Weight average molecular weight retention rate
(%)=[Mw1/Mw0].times.100 (viii)
[0299] Besides, the weight average molecular weight change rate of
the resin may also be given by the equivalent evaluation.
[0300] The resin composition of the present invention satisfies any
one of the following J1 to J2:
J1: In the 15% hydrochloric acid aqueous solution at 100.degree.
C., after 6 hours, a weight average molecular weight retention rate
of the resin composition is 50% or more, and after 24 hours, a
weight of a water-insoluble matter of the resin composition is 50%
or less; and J2: In the 15% hydrochloric acid aqueous solution at
120.degree. C., after 1 hour, a weight average molecular weight
retention rate of the resin composition is 50% or more, and after
24 hours, a weight of a water-insoluble matter of the resin
composition is 50% or less.
[0301] The range where the resin composition of the present
invention can be suitably used varies with the temperature. In J1
to J2, at a time earlier than after the prescribed fixed period of
time (6 hours or 1 hour), the weight average molecular weight
retention rate of the resin composition is preferably 50% or
more.
[0302] In J1, it is expressed that the fixed period of time is 6
hours and during that time, the weight average molecular weight of
the resin composition is kept, and the weight and shape of the
resin are kept at desired levels. From the viewpoint of exhibiting
the desired performance in the excavation technology in the oil
field or the like, in hot water under a chemically severe
condition, such as an acidic or basic condition, etc., after a
fixed period of time longer than 6 hours as defined in the present
invention, the weight average retention rate of the resin
composition may be 50% or more.
[0303] In J2, it is expressed that the fixed period of time is 1
hour and during that time, the weight average molecular weight of
the resin composition is kept, and the weight and shape of the
resin are kept at desired levels. From the viewpoint of exhibiting
the desired performance in the excavation technology in the oil
field or the like, in hot water under a chemically severe
condition, such as an acidic or basic condition, etc., after a
fixed period of time longer than 1 hour as defined in the present
invention, the weight average retention rate of the resin
composition may be 50% or more.
[0304] After the fixed period of time prescribed in each of J1 to
J2 (6 hours or 1 hour), the effect for sealing the acidic group by
the hydrolysis regulator (component D) vanishes, the decomposition
of the resin is promoted due to the autocatalysis of the acidic
group, and following that, the weight average molecular weight is
abruptly lowered. Furthermore, when the decomposition proceeds, the
resin becomes a water-soluble monomer, whereby it becomes soluble
in water. The matter that the instant phenomenon occurs quickly as
far as possible after the weight and shape of the resin are kept
for a fixed period of time is suitable on the occasion of using the
resin composition of the present invention in the excavation
technology in the oil field or the like. For that reason, it is
preferred that after 24 hours, the weight of the water-insoluble
matter of the resin composition is 50% or less. For the foregoing
reason, it is more preferred that after 18 hours, the weight of the
water-insoluble matter of the resin composition is 50% or less; it
is still more preferred that after 12 hours, the weight of the
water-insoluble matter of the resin composition is 50% or less; and
it is yet still more preferred that after 8 hours, the weight of
the water-insoluble matter of the resin composition is 50% or
less.
[0305] As for the resin composition of the present invention, it is
preferred that in the 15% hydrochloric acid aqueous solution at an
arbitrary temperature of 100.degree. C. or higher and 120.degree.
C. or lower, after 72 hours, the weight of the water-insoluble
matter of the resin composition is 10% or less. For example, on the
occasion of using the resin composition in the excavation
technology in the oil field or the like, the resin composition is
dissolved in water quickly after keeping the weight and shape of
the resin for a fixed period of time, whereby it can effectively
work. For that reason, it is preferred that in the 15% hydrochloric
acid aqueous solution at an arbitrary temperature of 100.degree. C.
or higher and 120.degree. C. or lower, after 72 hours, the weight
of the water-insoluble matter of the resin composition is 10% or
less.
[0306] From the viewpoints of treatment in water after the use and
exhibition of the desired performance, the water-insoluble matter
is low as far as possible, and after 72 hours, the weight of the
water-insoluble matter of the resin composition is more preferably
7% or less, still more preferably 5% or less, and especially
preferably 1% or less.
[0307] In the resin composition of the present invention, a content
of the hydrolysis regulator (component D) is 0.1 to 20 parts by
weight on the basis of 100 parts by weight of a total sum of the
aliphatic polyester containing, as a main component, a
water-soluble monomer (component C) and the hydrolysis regulator
(component D). When the content of the hydrolysis regulator
(component D) is less than 0.1 parts by weight, there may be the
case where the sufficient effect for sealing the acidic group and
the sufficient effect for keeping the molecular weight are not
exhibited in hot water under a chemically severe condition, such as
an acidic or basic condition, etc. When it is more than 20 parts by
weight, there may be the case where bleedout of the hydrolysis
regulator (component D) from the resin composition, worsening of
moldability, or degeneration of properties of a substrate takes
place. From such viewpoints, the addition amount of the hydrolysis
regulator (component D) is more preferably 0.5 to 10 parts by
weight, and still more preferably 1.0 to 7.0 parts by weight on the
basis of 100 parts by weight of a total sum of the aliphatic
polyester containing, as a main component, a water-soluble monomer
(component C) and the hydrolysis regulator (component D).
<Production Method of Resin Composition>
[0308] The resin composition of the present invention can be
produced by melt kneading the aliphatic polyester containing, as a
main component, a water-soluble monomer and the hydrolysis
regulator (component D).
[0309] Incidentally, in the case of adopting polylactic acid as the
aliphatic polyester containing, as a main component, a
water-soluble monomer (component C), poly(L-lactic acid) and
poly(D-lactic acid), each of which is the aliphatic polyester
containing, as a main component, a water-soluble monomer and having
autocatalysis (component C), and the hydrolysis regulator
(component D) are mixed to form a stereocomplex polylactic acid,
and simultaneously, the resin composition of the present invention
can also be produced. The resin composition of the present
invention can also be produced by mixing poly(L-lactic acid) and
poly(D-lactic acid) to form stereocomplex polylactic acid and then
mixing the hydrolysis regulator (component D).
[0310] The method of adding the hydrolysis regulator (component D)
to the aliphatic polyester containing, as a main component, a
water-soluble monomer (component C) and mixing them is not
particularly limited, and a conventionally known method, such as a
method of adding as a solution, a melt, or a master batch of the
aliphatic polyester containing, as a main component, a
water-soluble monomer (component C) to be applied; a method of
bringing a solid of the aliphatic polyester containing, as a main
component, a water-soluble monomer (component C) into contact with
a liquid having the hydrolysis regulator (component D) dissolved,
dispersed or melted therein, thereby penetrating the hydrolysis
regulator (component D) thereinto; and the like can be adopted.
[0311] In the case of adopting a method of adding as a solution, a
melt, or a master batch of the aliphatic polyester containing, as a
main component, a water-soluble monomer (component C) to be
applied, a method of addition using a conventionally known kneading
device can be adopted. On the occasion of kneading, a kneading
method in a solution state or a kneading method in a molten state
is more preferred from the viewpoint of uniform kneading
properties. The kneading device is not particularly limited, and
conventionally known vertical reaction vessels, mixing tanks, and
kneading tanks, or single-screw or multi-screw horizontal kneading
devices, for example, single-screw or multi-screw extruders and
kneader, and the like are exemplified. A mixing time is not
particularly specified, and though it varies with the mixing device
or mixing temperature, a time of 0.1 minutes to 2 hours, preferably
0.2 minutes to 60 minutes, and more preferably 0.2 minutes to 30
minutes is selected.
[0312] As the solvent, those which are inert to the aliphatic
polyester containing, as a main component, a water-soluble monomer
(component C) and the hydrolysis regulator (component D) can be
used. In particular, a solvent which has an affinity with the both
components and at least partially dissolves the both components
therein.
[0313] As the solvent, for example, hydrocarbon-based solvents,
ketone-based solvents, ester-based solvents, ether-based solvents,
halogen-based solvents, amide-based solvents, and the like can be
used.
[0314] Examples of the hydrocarbon-based solvent include hexane,
cyclohexane, benzene, toluene, xylene, heptane, decane, and the
like. Examples of the ketone-based solvent include acetone, methyl
ethyl ketone, diethyl ketone, cyclohexanone, isophorone, and the
like.
[0315] Examples of the ester-based solvent include ethyl acetate,
methyl acetate, ethyl succinate, methyl carbonate, ethyl benzoate,
diethylene glycol diacetate, and the like. Examples of the
ether-based solvent include diethyl ether, dibutyl ether,
tetrahydrofuran, dioxane, diethylene glycol dimethyl ether,
triethylene glycol diethyl ether, diphenyl ether, and the like.
Examples of the halogen-based solvent include dichloromethane,
chloroform, tetrachloromethane, dichloroethane,
1,1',2,2'-tetrachloroethane, chlorobenzene, dichlorobenzene, and
the like. Examples of the amide-based solvent include formamide,
N,N-dimethylformamide, N,N-dimethylacetamide,
N-methyl-2-pyrrolidone, and the like. These solvents can be used
alone or as a mixed solvent, if desired.
[0316] In the present invention, the solvent is applied in an
amount in the range of 1 to 1,000 parts by weight based on 100
parts by weight of the resin composition. When the amount of the
solvent is less than 1 part by weight, there is no meaning for the
application of the solvent. Although an upper limit value of the
use amount of the solvent is not particularly limited, it is about
1,000 parts by weight from the viewpoints of operability and
reaction efficiency.
[0317] In the case of adopting a method of bringing a solid of the
aliphatic polyester containing, as a main component, a
water-soluble monomer (component C) into contact with a liquid
having the hydrolysis regulator (component D) dissolved, dispersed
or melted therein, thereby penetrating the hydrolysis regulator
(component D) thereinto, a method of bringing a solid of the
aliphatic polyester containing, as a main component, a
water-soluble monomer (component B) into contact with the
hydrolysis regulator (component D) dissolved in a solvent as
described above; a method of bringing a solid of the resin
containing, as a main component, a water-soluble monomer and having
autocatalysis (component C) into contact with an emulsion liquid of
the hydrolysis regulator (component D); and the like can be
adopted.
[0318] As the contacting method, a method of dipping the aliphatic
polyester containing, as a main component, a water-soluble monomer
(component C); a method of coating the aliphatic polyester
containing, as a main component, a water-soluble monomer (component
C); a method of spraying on the aliphatic polyester containing, as
a main component, a water-soluble monomer (component C); and the
like can be suitably adopted.
[0319] Although it is possible to perform a sealing reaction of the
acidic group of the aliphatic polyester containing, as a main
component, a water-soluble monomer (component C) with the
hydrolysis regulator (component D) at a temperature of room
temperature (25.degree. C.) to about 300.degree. C., the sealing
reaction is more promoted at a temperature in the range of
preferably 50 to 280.degree. C., and more preferably 100 to
280.degree. C. from the viewpoint of reaction efficiency. As for
the aliphatic polyester containing, as a main component, a
water-soluble monomer (component C), the reaction is liable to be
more advanced at a temperature at which it is melted; however, in
order to inhibit volatilization, decomposition, or the like of the
hydrolysis regulator (component D), it is preferred to perform the
reaction at a temperature lower than 300.degree. C. For the
purposes of lowering the melting temperature of the aliphatic
polyester containing, as a main component, a water-soluble monomer
(component C) and increasing the stirring efficiency, it is
effective to apply a solvent.
[0320] Although the reaction is sufficiently rapidly advanced in
the absence of a catalyst, a catalyst for promoting the reaction
can also be used. As the catalyst, catalysts which are generally
used for the hydrolysis regulator (component B) can be applied.
These can be used alone or in combination of two or more kinds
thereof. Although an addition amount of the catalyst is not
particularly limited, it is preferably 0.001 to 1 part by weight,
more preferably 0.01 to 0.1 parts by weight, and most preferably
0.02 to 0.1 parts by weight based on 100 parts by weight of the
resin composition.
[0321] In the present invention, the hydrolysis regulator
(component D) may be used in a combination of two or more kinds
thereof. For example, with respect to the hydrolysis regulator
(component D) for performing the sealing reaction of the acidic
group at the early stage of the aliphatic polyester containing, as
a main component, a water-soluble monomer (component C) and the
hydrolysis regulator (component D) for performing the sealing
reaction of the acidic group in acidic water, separate materials
may be used.
[0322] Furthermore, it is preferred to jointly use an auxiliary
agent of the hydrolysis regulator (component D), namely an agent
for assisting the effect of the hydrolysis regulator (component D)
for the purpose of delaying the hydrolysis. Although any known
material can be used as such an agent, for example, at least one
compound selected from hydrotalcite, an alkaline earth metal oxide,
an alkaline earth metal hydroxide, and an alkaline earth metal
carbonate is exemplified. A content of the auxiliary agent is
preferably 0.1 to 30 parts by weight, more preferably 0.5 to 20
parts by weight, and still more preferably 0.7 to 10 parts by
weight based on 100 parts by weight of the hydrolysis regulator
(component D).
[0323] In the resin composition of the present invention, all of
known additives and fillers can be added and used within the range
where the effects of the invention are not lost. Examples thereof
include a stabilizer, a crystallization promoter, a filler, a
release agent, an antistatic agent, a plasticizer, an impact
resistance-improving agent, a terminal-sealing agent, and the
like.
[0324] Incidentally, from the viewpoint that the effects of the
invention are not lost, with respect to the additives, it is
important to not use a component which promotes the decomposition
of the aliphatic polyester containing, as a main component, a
water-soluble monomer (component C), for example, a phosphoric acid
component, a phosphite-based additive which is decomposed in the
resin composition to generate a phosphoric acid component, or the
like, or decrease its amount as far as possible, or to reduce
influences thereof by taking a method, such as deactivation, etc.
For example, a method of using a component capable of achieving
deactivation or retardation together with the hydrolysis regulator
(component D), or the like can be suitably adopted.
<Stabilizer>
[0325] The resin composition of the present invention can contain a
stabilizer, and all of the stabilizers described in the foregoing
first invention of the present application can be used. Its use
amount is also the same.
<Crystallization Promoter>
[0326] The resin composition of the present invention can contain
an organic or inorganic crystallization accelerator, and all of the
crystallization promoters described in the foregoing first
invention of the present application can be used. Its use amount is
also the same.
<Filler>
[0327] The resin composition of the present invention can contain
an organic or inorganic filler, and all of the fillers described in
the foregoing first invention of the present application can be
used. Its use amount is also the same.
<Release Agent>
[0328] The resin composition of the present invention can contain a
release agent, and all of the release agents described in the
foregoing first invention of the present application can be used.
Its use amount is also the same.
<Plasticizer>
[0329] The resin composition of the present invention can contain a
plasticizer, and all of the plasticizers described in the foregoing
first invention of the present application can be used. Its use
amount is also the same.
<Impact Resistance-Improving Agent>
[0330] The resin composition of the present invention can contain
an impact resistance-improving agent, and all of the impact
resistance-improving agents described in the foregoing first
invention of the present application can be used. Its use amount is
also the same.
<Others>
[0331] In the resin composition of the present invention, the other
components described in the foregoing first invention of the
present application (e.g., a thermosetting resin, a flame
retardant, a dye, a pigment, a colorant, a slidability-improving
agent, etc.) can be used within the range where the gist of the
present invention is not deviated.
<Molded Article>
[0332] A molded article made of the resin composition of the
present invention can be formed by means of injection molding,
extrusion molding, vacuum or pressure molding, blow molding, or the
like. Examples of the molded article include a pellet, a fiber, a
textile, a fiber structure, a film, a sheet, a sheet nonwoven
fabric, and the like.
[0333] In producing the molded article made of the resin
composition of the present invention, all of the methods described
in the foregoing first invention of the present application can be
adopted, and conditions thereof are also the same.
[0334] The resin composition of the present invention can be used
as a pulverized chip or a powder by using, as a raw material, the
above-exemplified molded article or other molded article obtained
by a known molding method. As for such a pulverized chip or powder,
a material obtained by a conventionally known method including a
pulverization method, a shredding method, a cutting method, and a
reprecipitation method using a solvent, and a subsequent particle
size classification method can be suitably used.
[0335] The pulverized chip or powder of the present invention can
be used alone, and it can also be used in combination with a molded
article of other form or other material, such as a resin, a metal
compound, etc.
[0336] If desired, the molded article of the present invention can
be covered by using a solid material, such as other resins, metal
compounds, etc., or a liquid material, such as organic solvents,
oils, gels, etc. In that case, in order to achieve the target
decomposition performance, it is preferred to adjust the type or
thickness of a covering material, adhesiveness to the molded
article of the present invention, or the like.
EXAMPLES
[0337] The first invention of the present application is hereunder
more specifically explained by reference to Examples. The
respective physical properties were measured by the following
methods.
(1) Weight Average Molecular Weight (Mw) and Number Average
Molecular Weight (Mn):
[0338] A weight average molecular weight and a number average
molecular weight of a polymer were measured by means of gel
permeation chromatography (GPC) and converted into standard
polystyrene.
[0339] As for the GPC measurement, the following detector and
column were used, chloroform was used as an eluant, and 10 .mu.L of
a sample in a concentration of 1 mg/mL (chloroform containing 1%
hexafluoroisopropanol) was injected at a temperature of 40.degree.
C. and at a flow rate of 1.0 mL/min and measured.
[0340] Detector: Differential refractometer (manufactured by
Shimadzu Corporation), RID-6A
[0341] Column: Column in which TSKgel G3000HXL, TSKgel G4000HXL,
TSKgel G5000HXL, and TSKguardcolumn HXL-L (all of which are
manufactured by Tosoh Corporation) are connected in series, or
column in which TSKgel G2000HXL, TSKgel G3000HXL, and
TSKguardcolumn HXL-L (all of which are manufactured by Tosoh
Corporation) are connected in series.
(2) Carboxyl Group Concentration:
[0342] A carboxyl group concentration of each of resin compositions
of the Examples was confirmed by means of .sup.1H-NMR. ECA600,
manufactured by JEOL Ltd. was used for the NMR. The measurement was
performed by using deuterochloroform and hexafluoroisopropanol as a
solvent and adding hexylamine thereto.
[0343] With respect to other samples, each sample was dissolved in
purified o-cresol and further dissolved under a nitrogen gas
stream, and the solution was titrated with an ethanol solution of
0.05N potassium hydroxide while using Bromocresol Blue as an
indicator.
(3) DSC Measurement of Stereocomplex Crystallization Degree [S
(%)], Crystal Melting Temperature, and the Like:
[0344] Using DSC (manufactured by TA Instruments, TA-2920), in a
first cycle, a sample was subjected to temperature elevation to
250.degree. C. at a rate of 10.degree. C./min under a nitrogen gas
stream and measured for a glass transition temperature (Tg), a
stereocomplex phase polylactic acid crystal melting temperature
(Tm*), a stereocomplex phase polylactic acid crystal melting
enthalpy (.DELTA.Hms), and a homo-phase polylactic acid crystal
melting enthalpy (.DELTA.Hmh).
[0345] The above-described measurement sample was quickly cooled
and subsequently subjected to second cycle measurement under the
same condition, thereby measuring a crystallization starting
temperature (Tc*) and a crystallization temperature (Tc). A
stereocomplex crystallization degree (S) is a value determined from
the stereocomplex phase and homo-phase polylactic acid crystal
melting enthalpies as obtained by the above-described measurement
according to the following equation (a).
S (%)=[.DELTA.Hms/(.DELTA.Hmh+.DELTA.Hms)].times.100 (a)
[0346] (Here, .DELTA.Hms is a melting enthalpy of the stereocomplex
phase polylactic acid crystal, and .DELTA.Hmh is a melting enthalpy
of the homo-phase polylactic acid crystal.)
(4) Water Resistance Evaluation of Hydrolysis Regulator:
(4-1) Water Resistance Evaluation Using Dimethyl Sulfoxide:
[0347] 2 g of water was added to a system in which 1 g of a sample
was dissolved or partially dissolved in 50 mL of dimethyl
sulfoxide, the resultant was stirred while refluxing at 120.degree.
C. for 5 hours, and thereafter, the obtained dissolved sample
proportion was measured by means of HPLC or .sup.1H-NMR.
[0348] ECA600, manufactured by JEOL Ltd. was used for the NMR.
Deuterodimethyl sulfoxide was used as a solvent, and an agent
amount after 5 hours was determined from a change amount of the
structure (integrated value).
[0349] The HPLC was carried out under the following condition, and
the agent amount was determined from an area of the agent amount
after 5 hours while defining an area of the agent amount at 0 hour
as 100%.
[0350] Apparatus: Ultra high performance liquid chromatography,
"Nexera (registered trademark)", manufactured by Shimadzu
Corporation
[0351] UV detector: Manufactured by Shimadzu Corporation, SPD-20A,
254 nm
[0352] Column: Manufactured by GL Sciences Inc., Inertsil Ph-3, 3
.mu.m, 4.6 mm.times.150 mm (or a column equivalent thereto is also
usable)
[0353] Column temperature: 40.degree. C.
[0354] Preparation of sample: A dimethyl sulfoxide solution was
diluted 500 times with DMF and used.
[0355] Injection amount: 2 .mu.L
[0356] Mobile phase: A: methanol, B: water
[0357] Flow rate: 1.0 mL/min (0 min: A/B=50/50.fwdarw.10 min:
A/B=98/2.fwdarw.kept until 18 min.fwdarw.23 min:
A/B=50/50.fwdarw.30 min)
[0358] Using the obtained agent amount after 5 hours, the water
resistance was determined according to the following equation
(ix).
Water resistance=[(Agent amount after treatment for 5
hours)/(Initial agent amount)].times.100 (ix)
(4-2) Other Water Resistance Evaluation (Exemplifying the Case
where the Component B is Dissolved in Tetrahydrofuran):
[0359] 2 g of water was added to a system in which 1 g of a sample
was dissolved in 25 mL of tetrahydrofuran and 25 mL of dimethyl
sulfoxide, the resultant was stirred while refluxing at 120.degree.
C. for 5 hours, and thereafter, the obtained dissolved sample
proportion was measured by means of FT-IR.
[0360] The FT-IR was carried out under the following condition, and
using areas of one group which does not change by the treatment of
the agent (e.g., an alkyl chain portion, etc.) and a carbodiimide
group, the agent amount was determined from a quotient of the area
of the carbodiimide group and the area of the group which does not
change after 5 hours while defining a quotient of the area of the
carbodiimide group and the area of the group which does not change
at 0 hour as 100.
[0361] Using the obtained agent amount after 5 hours, the water
resistance was determined according to the foregoing equation
(ix).
[0362] Apparatus: Manufactured by Thermo Fisher Scientific K.K.,
"Nicolet (registered trademark) iN10"
[0363] Measurement method: Microscopic transmission method
[0364] Measurement visual field: 50 .mu.m.times.50 .mu.m
[0365] Resolution: 4 cm.sup.-1
[0366] Measurement wave number: 4,000 to 740 cm.sup.-1
[0367] Cumulative number: 128 times
[0368] Preparation of sample: The dissolved sample was placed on a
barium fluoride plate to volatize the solvent.
(5) Reactivity Evaluation of Hydrolysis Regulator with Acidic
Group:
[0369] With respect to a resin composition obtained by using
polylactic acid "NW3001D", manufactured by NatureWorks LLC (MW:
150,000, carboxyl group concentration: 22.1 equivalents/ton) as
polylactic acid for evaluation and adding it in an amount such that
the group of a hydrolysis regulator, reacting with the carboxyl
group, was 33.15 equivalents/ton and melt kneading the mixture
under a nitrogen atmosphere at a resin temperature of 190.degree.
C. and at a rotation rate of 30 rpm for 1 minute by using a Labo
Plasto mill (manufactured by Toyo Seiki Seisaku-Sho, Ltd.), a
carboxyl group concentration was measured, and the reactivity with
an acidic group was determined according to the following equation
(x).
Reactivity (%)=[{(Carboxyl group concentration of polylactic acid
for evaluation)-(Carboxyl group concentration of resin
composition)}/(Carboxyl group concentration of polylactic acid for
evaluation)].times.100 (x)
(6) Moist Heat Evaluation in High-Temperature Hot Water:
[0370] A closed melting crucible (manufactured by OM Lab-Tech Co.,
Ltd., MR-28, capacity: 28 mL) preheated at 110.degree. C. was
charged with 300 mg of a resin composition and 12 mL of distilled
water and hermetically sealed, and the crucible was allowed to
stand within a hot air dryer (manufactured by Koyo Thermo Systems
Co., Ltd., KLO-45M,) previously kept at a prescribed temperature
(150.degree. C., 170.degree. C., or 190.degree. C.).
[0371] After allowing the crucible to stand, a time after the
crucible was allowed to stand in the hot air dryer until the
temperature in the interior of the crucible reached a prescribed
test temperature was defined as a point of time of starting the
test, at a point of time when a fixed period of time elapsed from
this point of time of starting the test, the crucible was taken out
from the hot air dryer.
[0372] The crucible taken out from the hot air dryer was air-cooled
for 20 minutes and then cooled to ordinary temperature for 10
minutes by means of water cooling, and thereafter, the crucible was
opened to recover the sample and water in the interior of the
crucible. The sample and water in the interior of the crucible were
subjected to filtration using a filter paper (in conformity with
JIS P3801:1995, class 5A); the resin composition remaining on the
filter paper was dried at 60.degree. C. under a vacuum of 133.3 Pa
or less for 3 hours; thereafter, the weight of the resin
composition and the carboxyl group concentration were measured. The
weight was determined according to the following equation (xi).
Weight (%)=[(Weight of resin composition after treatment for a
fixed period of time)/(Weight of resin composition at the initial
stage)].times.100 (xi)
[0373] A weight average molecular weight of the resin composition
obtained by the treatment was measured, and a molecular weight
retention rate was evaluated using a weight average molecular
weight before the treatment.
(7) Purity Evaluation of
bis(2,6-diisopropylphenyl)carbodiimide:
[0374] A purity of bis(2,6-diisopropylphenyl) carbodiimide was
measured by means of HPLC. The HPLS was carried out under the
following condition, and the purity was determined from an
area.
[0375] LC main body: LC20A (manufactured by Shimadzu
Corporation)
[0376] Column: Developsil ODS-MG-3
[0377] Column temperature: 40.degree. C.
[0378] Detection wavelength: 254 nm
[0379] Flow rate: 0.2 mL/min
[0380] Preparation of sample: A sample was diluted with
acetonitrile and used.
[0381] Injection amount: 1 .mu.L
[0382] Mobile phase: A: water, B: acetonitrile
[0383] Gradient Condition:
[0384] Time 0.fwdarw.1.fwdarw.15.fwdarw.30 (min)
[0385] Bconc.: 60.fwdarw.60.fwdarw.100.fwdarw.100(%)
(8) Purity Evaluation of bis(2,6-diisopropylphenyl)carbodiimide
(Measurement of Contents of a Compound Represented by the Foregoing
Chemical Formula (4) and a Compound Represented by the Foregoing
Chemical Formula (5)):
[0386] Other compounds contained in
bis(2,6-diisopropylphenyl)carbodiimide to be applied to a resin
composition were measured by means of .sup.1H-NMR. ECA600,
manufactured by JEOL Ltd. was used for the NMR. Deuterochloroform
was used as a solvent. A total sum of the contents of the compound
represented by the foregoing chemical formula (4) and the compound
represented by the foregoing chemical formula (5) was calculated
from an integrated value of the sample.
##STR00016##
[0387] (In the formula, each of R.sub.8 to R.sub.11 is an aliphatic
group having 3 carbon atoms, and at least one of them is a propyl
group, with the other group or groups being an isopropyl
group.)
##STR00017##
[0388] (In the formula, each of R.sub.12 to R.sub.15 is an
aliphatic group having 3 carbon atoms, and at least one group of
them is substituted on a position other than the ortho
position.)
[0389] In the case where a peak derived from the compound
represented by the foregoing chemical formula (4) or the compound
represented by the foregoing chemical formula (5) could not be
detected, its content is expressed as "less than 0.1%".
(9) Moist Heat Evaluation in Warm Water:
[0390] After treating a sample under a condition at 80.degree. C.
and 95% RH for 100 hours by a constant temperature and humidity
machine, a weight average molecular weight of the resulting sample
was measured, and a molecular weight retention rate was evaluated
using a weight average molecular weight before the treatment.
[0391] Compounds used in the present Examples are hereunder
explained.
<Resin Containing, as a Main Component, a Water-Soluble Monomer
and Having Autocatalysis (Component A)>
[0392] The following polylactic acids were produced and used as the
resin containing, as a main component, a water-soluble monomer and
having autocatalysis (component A).
[Production Example 1] Poly(L-Lactic Acid) Resin
[0393] To 100 parts by weight of L-lactide (manufactured by
Musashino Chemical Laboratory, Ltd., optical purity: 100%), 0.005
parts by weight of tin octylate was added; the contents were
allowed to react with each other under a nitrogen atmosphere at
180.degree. C. for 2 hours by a reactor equipped with a stirring
blade; phosphoric acid of 1.2 time equivalent to the tin octylate
was added; and thereafter, the remaining lactide was removed at
13.3 Pa, followed by chipping, thereby obtaining a poly(L-lactic
acid) resin.
[0394] The obtained poly(L-lactic acid) resin had a weight average
molecular weight of 152,000, a melting enthalpy (.DELTA.Hmh) of 49
J/g, a melting point (Tmh) of 175.degree. C., a glass transition
point (Tg) of 55.degree. C., and a carboxyl group concentration of
13 equivalents/ton.
[Production Example 2] Poly(D-Lactic Acid) Resin
[0395] The same operations as those in Production Example 1 were
followed, except that D-lactide (manufactured by Musashino Chemical
Laboratory, Ltd., optical purity: 100%) was used in place of the
L-lactide in Production Example 1, thereby obtaining a
poly(D-lactic acid) resin.
[0396] The obtained poly(D-lactic acid) resin had a weight average
molecular weight of 151,000, a melting enthalpy (.DELTA.Hmh) of 48
J/g, a melting point (Tmh) of 175.degree. C., a glass transition
point (Tg) of 55.degree. C., and a carboxyl group concentration of
14 equivalents/ton.
[Production Example 3] Stereocomplex Polylactic Acid (A1)
[0397] 100 parts by weight in total of a polylactic acid resin
consisting of 50 parts by weight of the poly(L-lactic acid) resin
and 50 parts by weight of the poly(D-lactic acid) resin obtained in
Production Examples 1 and 2, respectively and 0.04 parts by weight
of phosphoric acid-2,2'-methylenebis(4,6-di-tert-butylphenyl)
sodium ("ADEKASTAB (registered trademark)" NA-11, manufactured by
ADEKA Corporation) were mixed by a blender; thereafter, the mixture
was dried at 110.degree. C. for 5 hours and then supplied into a
vent type double-screw extruder having a diameter of 30 mm.phi.
(manufactured by The Japan Steel Works, LTD., TEX30XSST); and the
resultant was melt extruded at a cylinder temperature of
250.degree. C., a screw rotation rate of 250 rpm, a discharge
amount of 5 kg/h, and a vent reduced pressure of 3 kPa, followed by
pelletization, thereby obtaining stereocomplex polylactic acid
(A1).
[0398] The obtained stereocomplex polylactic acid resin (A1) had a
weight average molecular weight of 130,000, a melting enthalpy
(.DELTA.Hms) of 56 J/g, a melting point (Tms) of 220.degree. C., a
glass transition point (Tg) of 58.degree. C., a carboxyl group
concentration of 16 equivalents/ton, and a stereocomplex
crystallization degree (S) of 100%.
A2: Polylactic acid "NW3001D", manufactured by NatureWorks LLC (MW:
150,000, carboxyl group concentration: 22.1 equivalents/ton)
<Hydrolysis Regulator (Component B)>
[0399] The following additives were used as the hydrolysis
regulator (component B).
B1: DIPC (carbodiimide compound, manufactured by Kawaguchi Chemical
Industry Co., Ltd.)
[0400] The purity of bis(2,6-diisopropylphenyl)carbodiimide is
99.9% or more, and the total sum of the compound represented by the
foregoing chemical formula (4) and the compound represented by the
foregoing chemical formula (5) is less than 0.1%.
B1': Bis(2,6-diisopropylphenyl)carbodiimide (synthesized by a known
method)
[0401] The purity of bis(2,6-diisopropylphenyl)carbodiimide is
90.9%, the total sum of the compound represented by the foregoing
chemical formula (4) and the compound represented by the foregoing
chemical formula (5) is 8.7%, and the content of other impurity
component is 0.4%.
B2: "STABAXOL (registered trademark)" P (carbodiimide compound,
manufactured by Rhein Chemie) B3: "CARBODILITE (registered
trademark)" LA-1 (carbodiimide compound, manufactured by Nisshinbo
Chemical Inc.) B4: 1,3-Di-p-tolylcarbodimide (carbodiimide
compound, manufactured by Aldrich) B5: "CELLOXIDE (registered
trademark)" 2021P (epoxy compound, manufactured by Daicel
Corporation) B6: BOX-210 (oxazoline compound, manufactured by
Takemoto Oil & Fat Co., Ltd.)
[0402] The water resistance and the reactivity with an acidic group
of each component B are shown in Table 1. Materials in which the
water resistance is 95% or more, and the reactivity with an acidic
group is 50% or more were judged as ".largecircle." and used for
the Examples. The other materials were judged as "x" and used for
the Comparative Examples. With respect to B1 and B4 to B6, the
water resistance evaluation using dimethyl sulfoxide was performed,
and with respect to B2 and B3, the other water resistance
evaluation was performed.
Example 1
[0403] A1 and B1 were mixed in weight parts shown in Table 2 and
melt kneaded under a nitrogen atmosphere at a resin temperature of
230.degree. C. and at a rotation rate of 30 rpm for 1.5 minutes by
using a Labo Plasto mill (manufactured by Toyo Seiki Seisaku-Sho,
Ltd.), thereby obtaining a resin composition. The obtained resin
composition was subjected to moist heat evaluation in
high-temperature hot water at 170.degree. C. The evaluation results
are shown in Table 2.
Example 2
[0404] A resin composition was prepared in the same manner as that
in Example 1, except that B1 was changed to B2, and evaluated by
the same method. The evaluation results are shown in Table 2.
Comparative Examples 1 to 4
[0405] Resin compositions were prepared in the same manner as that
in Example 1, except that B1 was changed to B3 to B6, respectively.
The evaluation results are shown in Table 2.
Example 3
[0406] A resin composition was prepared in the same manner as that
in Example 1, except that the amounts of A1 and B1 were changed to
weight parts shown in Table 2, respectively, and the obtained resin
composition was subjected to moist heat evaluation in
high-temperature hot water at 190.degree. C. The evaluation results
are shown in Table 2. The molecular weight retention rate evaluated
before and after keeping in hot water at 190.degree. C. for 1 hour
was 46%.
Example 4
[0407] A resin composition was prepared in the same manner as that
in Example 3, except that B1 was changed to B2, and evaluated by
the same method. The evaluation results are shown in Table 2.
Comparative Examples 5 to 8
[0408] Resin compositions were prepared in the same manner as that
in Example 3, except that B1 was changed to B3 to B6, respectively.
The evaluation results are shown in Table 2.
Example 5
[0409] A resin composition was prepared in the same manner as that
in Example 1, except that A1 was changed to A2, and the obtained
resin composition was subjected to moist heat evaluation in
high-temperature hot water at 150.degree. C. The evaluation results
are shown in Table 2.
Comparative Example 9
[0410] A resin composition was prepared in the same manner as that
in Example 5, except that B1 was changed to B3, and evaluated by
the same method. The evaluation results are shown in Table 2.
Example 6
[0411] A resin composition was prepared in the same manner as that
in Example 3; the obtained resin composition was dehumidified and
dried at 40.degree. C. for 8 hours and then melted at 230.degree.
C.; and the resultant was discharged from a spinneret having an
aperture of 0.2 mm and stretched 3.5 times at 65.degree. C.,
followed by crystallization at 180.degree. C. The obtained fiber
was cut by a rotary cutter, thereby obtaining a short fiber having
a yarn diameter of 50 .mu.m and a length of 8 mm. This fiber was
subjected to moist heat evaluation in high-temperature hot water at
190.degree. C. The evaluation results are shown in Table 2.
Example 7
[0412] A fiber was prepared in the same manner as that in Example
6, except that B1 was changed to B2, and evaluated by the same
method. The evaluation results are shown in Table 2.
TABLE-US-00001 TABLE 1 Component B Evaluation B1 B2 B3 B4 B5 B6
Water resistance (%) 100 100 82.6 0 100 100 Reactivity with acidic
group 85.7 73.2 87.3 84.8 5.9 26.7 (%) Judgement .smallcircle.
.smallcircle. x x x x
TABLE-US-00002 TABLE 2 Formulation (weight parts) Component B B1'
Component A (purified A1 A2 B1 B1' product) B2 B3 B4 B5 B6 Shape
Example 1 97.5 2.5 Pellet Example 2 97.5 2.5 Pellet Example 3 90 10
Pellet Example 4 90 10 Pellet Example 5 97.5 2.5 Pellet Example 6
90 10 Fiber Example 7 90 10 Fiber Example 8 90 10 Pellet Example 9
90 10 Pellet Comparative 97.5 2.5 Pellet Example 1 Comparative 97.5
2.5 Pellet Example 2 Comparative 97.5 2.5 Pellet Example 3
Comparative 97.5 2.5 Pellet Example 4 Comparative 90 10 Pellet
Example 5 Comparative 90 10 Pellet Example 6 Comparative 90 10
Pellet Example 7 Comparative 90 10 Pellet Example 8 Comparative
97.5 2.5 Pellet Example 9 Carboxyl group con- centration of resin
Weight of resin composition (eq./t) composition (%) Temperature Hot
water Hot water Hot water Hot water of hot water treatment
treatment treatment treatment (.degree. C.) 0 h 1 h 1 h 24 h
Example 1 170 0 0 97 Less than 1% Example 2 170 0 0 99 Less than 1%
Example 3 190 0 0 99 Less than 1% Example 4 190 0 4.5 98 Less than
1% Example 5 150 0 0 100 Less than 1% Example 6 190 0 0 92 Less
than 1% Example 7 190 0 7.7 88 Less than 1% Example 8 190 0 0 98
Less than 1% Example 9 190 0 0 98 Less than 1% Comparative 170 0
83.3 98 Less than 1% Example 1 Comparative 170 0 317.9 83 Less than
1% Example 2 Comparative 170 6.3 118.7 97 Less than 1% Example 3
Comparative 170 0 361.6 78 Less than 1% Example 4 Comparative 190 0
-- Less than 1% -- Example 5 Comparative 190 0 -- Less than 1% --
Example 6 Comparative 190 0.6 -- Less than 1% -- Example 7
Comparative 190 0 -- Less than 1% -- Example 8 Comparative 150 0
277.4 97 Less than 1% Example 9 * In the resin composition of
Example 3, the molecular weight retention rate evaluated before and
after keeping in hot water at 190.degree. C. for 1 hour was 46%. In
the resin composition of Example 8, the molecular weight retention
rate evaluated before and after keeping in hot water at 190.degree.
C. for 1 hour was 47%. In the resin composition of Example 9, the
molecular weight retention rate evaluated before and after keeping
in hot water at 190.degree. C. for 1 hour was 32%.
[0413] From these results, it is understood that in the case of
using, as the hydrolysis regulator, B1 and B2 each satisfying both
the water resistance and the reactivity with an acidic group, the
resin composition can realize the desired performance in
high-temperature hot water, namely the performance in which the
resin composition is quickly decomposed after keeping the weight
and shape of the resin in high-temperature hot water for a fixed
period of time. In addition, it is understood that in the case of
using B3 to B6, each of which does not satisfy at least either the
water resistance or the reactivity with an acidic group, the
decomposition of the resin composition is fast, so that the
satisfactory performance is not obtained.
[0414] Incidentally, in the Examples, with respect to the materials
in which the weight thereof is less than 1% after the treatment in
high-temperature hot water, on the basis of judgement that the
decomposition thoroughly proceeded, the measurement of the carboxyl
group concentration and the moist heat evaluation in
high-temperature hot water for a long time were not performed. The
corresponding portions in Table 2 are designated as "-".
Example 8
[0415] 100 g of B1' was added to 200 mL of methanol, completely
dissolved at 60.degree. C., and then cooled to room temperature. A
deposited crystal was recovered by filtration and dried to obtained
a purified product. The purity of
bis(2,6-diisopropylphenyl)carbodiimide was 99.9% or more, and the
total sum content of the compound represented by the foregoing
chemical formula (4) and the compound represented by the foregoing
chemical formula (5) was less than 0.1%.
[0416] A resin composition was prepared in the same manner as that
in Example 3, except that the obtained purified product was used in
place of B1, and evaluated by the same method. The evaluation
results are shown in Table 2. The molecular weight retention rate
was 47%.
Example 9
[0417] A resin composition was prepared in the same manner as that
in Example 3, except that B1 was changed to B1', and evaluated by
the same method. The evaluation results are shown in Table 2. The
molecular weight retention rate was 32%.
Reference Example 1
[0418] The resin composition prepared in Example 3 was treated
under a condition at 80.degree. C. and 95% RH for 100 hours by a
constant temperature and humidity machine. The molecular weight
retention rate after the treatment was 91%.
Reference Example 2
[0419] A resin composition was prepared in the same manner as that
in Example 3, except that B1 was changed to B1', and the obtained
resin composition was treated under a condition at 80.degree. C.
and 95% RH for 100 hours by a constant temperature and humidity
machine. The molecular weight retention rate after the treatment
was 92%.
[0420] From these results, it is understood that in the case where
the component B is bis(2,6-diisopropylphenyl) carbodiimide, when
the total sum content of the compound represented by the foregoing
chemical formula (4) and the compound represented by the foregoing
chemical formula (5) is small, in particular, the effect when used
in high-temperature hot water according to the present invention is
enhanced. It is understood that in view of the fact that it was
also confirmed that this enhancement of the effect is not exhibited
as a meaningful difference in warm water at 80.degree. C., this is
an important factor in the application with which the present
invention is mainly concerned.
[0421] The second invention of the present application is hereunder
more specifically explained by reference to Examples. Th respective
physical properties were measured by the following methods.
(10) Weight average molecular weight (Mw) and number average
molecular weight (Mn):
[0422] A weight average molecular weight and a number average
molecular weight of a polymer were measured by means of gel
permeation chromatography (GPC) and converted into standard
polystyrene.
[0423] As for the GPC measurement, the following detector and
column were used, chloroform was used as an eluant, and 10 .mu.L of
a sample in a concentration of 1 mg/mL (chloroform containing 1%
hexafluoroisopropanol) was injected at a temperature of 40.degree.
C. and at a flow rate of 1.0 mL/min and measured.
[0424] Detector: Differential refractometer (manufactured by
Shimadzu Corporation), RID-6A
[0425] Column: Column in which TSKgel G3000HXL, TSKgel G4000HXL,
TSKgel G5000HXL, and TSKguardcolumn HXL-L (all of which are
manufactured by Tosoh Corporation) are connected in series, or
column in which TSKgel G2000HXL, TSKgel G3000HXL, and
TSKguardcolumn HXL-L (all of which are manufactured by Tosoh
Corporation) are connected in series.
(11) Carboxyl Group Concentration:
[0426] A sample was dissolved in purified o-cresol and further
dissolved under a nitrogen gas stream, and the solution was
titrated with an ethanol solution of 0.05N potassium hydroxide
while using Bromocresol Blue as an indicator.
(12) Reactivity Evaluation with Acidic Group of Hydrolysis
Regulator:
[0427] With respect to a resin composition obtained by using
polylactic acid "NW3001D", manufactured by NatureWorks LLC (MW:
150,000, carboxyl group concentration: 24.1 equivalents/ton) as
polylactic acid for evaluation, adding 5 parts by weight of a
hydrolysis regulator to 95 parts by weight of the polylactic acid,
and melt kneading the mixture under a nitrogen atmosphere at a
resin temperature of 200.degree. C. and at a rotation rate of 30
rpm for 2 minutes by using a Labo Plasto mill (manufactured by Toyo
Seiki Seisaku-Sho, Ltd.), a carboxyl group concentration after
treatment in a 15% hydrochloric acid aqueous solution at
100.degree. C. for 3 hours was evaluated, a carboxy group
concentration of the polylactic acid for evaluation was similarly
measured after treatment in a 15% hydrochloric acid aqueous
solution at 100.degree. C. for 3 hours, and the reactivity with an
acidic group was determined according to the following equation
(xii).
Reactivity (%)=[{(Carboxyl group concentration of polylactic acid
for evaluation after treatment in 15% hydrochloric acid aqueous
solution at 100.degree. C. for 3 hours)-(Carboxyl group
concentration of resin composition after treatment in 15%
hydrochloric acid aqueous solution at 100.degree. C. for 3
hours)}/(Carboxyl group concentration of polylactic acid for
evaluation after treatment in 15% hydrochloric acid aqueous
solution at 100.degree. C. for 3 hours)].times.100 (xii)
(13) Decomposability Evaluation in Acidic Aqueous Solution:
[0428] A glass-made screw-capped test tube (manufactured by Maruemu
Corporation, NN-13, capacity: about 5 mL) was charged with 50 mg of
a resin composition (one having been previously crystallized by a
heat treatment at 110.degree. C. for 10 minutes and having a
chip-like shape of 0.5 mm to 2 mm in each side) and mL of a 15%
hydrochloric acid aqueous solution and hermetically sealed. The 15%
hydrochloric acid aqueous solution was prepared by diluting
hydrochloric acid (manufactured by Wako Pure Chemical Industries,
Ltd., Special grade, 35 to 37%) with distilled water and subjected
to neutralization titration with a sodium hydroxide aqueous
solution standard liquid, thereby confirming the concentration.
[0429] In the case where the test temperature was 100.degree. C. or
lower, the above-described test tube was allowed to stand within a
hot air dryer (manufactured by Toyo Seiki Seisaku-Sho, Ltd.,
FC-410) having been kept at a prescribed temperature in advance.
After elapsing a prescribed time, the test tube was taken out and
cooled to ordinary temperature (25.degree. C.) in a hermetically
sealed state of the test tube by means of water cooling.
[0430] In the case where the test temperature was higher than
100.degree. C. and 130.degree. C. or lower, the above-described
test tube was allowed to stand within a pressure cooker
(manufactured by Espec Corporation, HAST Chamber EHS-221M). After
the temperature within the pressure cooker reached the test
temperature, and a prescribed time elapsed, the temperature
decrease was commenced. After 10 minutes, the test tube was taken
out from the pressure cooker and cooled to ordinary temperature
(25.degree. C.) in a hermetically sealed state of the test tube by
means of water cooling.
[0431] After cooling the test tube to ordinary temperature
(25.degree. C.), the test tube was opened, the resin composition in
the interior was filtered using a glass filter (manufactured by
Sibata Scientific Technology Ltd., 3GP100, pore size: 40 to 100
.mu.m), and the resin composition remaining on the glass filter was
washed with a large amount of distilled water. The washed resin
composition was dried at ordinary temperature (25.degree. C.) under
a vacuum of 133.3 Pa or less for 1 hour, and thereafter, the weight
of the resin composition was measured. The weight of the
water-insoluble matter was calculated according to the following
equation (xiii).
Weight of water-insoluble matter (%)=[(Weight of resin composition
recovered by filtration after decomposition test)/(Weight of resin
composition before decomposition test)].times.100 (xiii)
[0432] With respect to the resin composition after the
decomposition test, the weight average molecular weight (Mw) was
measured by means of gel permeation chromatography (GPC), and its
value was designated as Mw1. Mw of the resin composition before the
above-described decomposition test was measured by means of GPC,
and its value is designated as Mw0. The weight average molecular
weight retention rate was calculated according to the following
equation (xiv).
Weight average molecular weight retention rate
(%)=[Mw1/Mw0].times.100 (xiv)
[0433] Compounds used in the present Examples are hereinunder
explained.
<Aliphatic Polyester Containing, as a Main Component, a
Water-Soluble Monomer (Component C)>
[0434] "NW3001D", manufactured by NatureWorks LLC (MW: 150,000,
carboxyl group concentration: 24.1 equivalents/ton) was used as the
aliphatic polyester containing, as a main component, a
water-soluble monomer (component C).
<Hydrolysis Regulator (Component D)>
[0435] The following additives were used as the hydrolysis
regulator (component D).
D1: Carbodiimide compound CC1 described in Production Example 1 D2:
"CARBODILITE (registered trademark)" LA-1 (carbodiimide compound,
manufactured by Nisshinbo Chemical Inc.) D3: DIPC (carbodiimide
compound, manufactured by Kawaguchi Chemical Industry Co., Ltd.)
D4: "CELLOXIDE (registered trademark)" 2021P (epoxy compound,
manufactured by Daicel Corporation) D5: BOX-210 (oxazoline
compound, manufactured by Takemoto Oil. & Fat Co., Ltd.)
[0436] The reactivity with an acidic group of each hydrolysis
regulator (component D) is shown in Table 3. Materials in which the
reactivity with an acidic group is 30% or more were judged as
".largecircle." and used for the Examples. The other materials were
judged as "x" and used for the Comparative Examples. Incidentally,
the case where the value of the reactivity was a minus value was
expressed as "0" and judged as "x".
[Production Example 4] Synthesis of Hydrolysis Regulator (D1)
[0437] In a reaction apparatus equipped with a stirring device and
a heating device, o-nitrophenol (0.11 moles), pentaerythrityl
tetrabromide (0.025 moles), potassium carbonate (0.33 moles), and
200 mL of N,N-dimethylformamide were charged under an N.sub.2
atmosphere; after reaction at 130.degree. C. for 12 hours, DMF was
removed under reduced pressure; and the obtained solid was
dissolved in 200 mL of dichloromethane, followed by liquid
separation with 100 mL of water three times. An organic layer was
dehydrated over 5 g of sodium sulfate, and the dichloromethane was
removed under reduced pressure to obtain an intermediate product D
(nitro body).
[0438] Subsequently, the intermediate product D (0.1 moles), 5%
palladium on carbon (Pd/C) (2 g), and 400 mL of
ethanol/dichloromethane (70/30) were charged in a reaction
apparatus equipped with a stirring device; hydrogen substitution
was performed 5 times; the contents were allowed to react at
25.degree. C. in a state where hydrogen was always supplied; and
when a decrease of hydrogen varnished, the reaction was finished.
The PD/C was recovered, and the mixed solvent was removed to obtain
an intermediate product E (amine body).
[0439] Subsequently, in a reaction apparatus equipped with a
stirring device, a heating device, and a dropping funnel,
triphenylphosphine dibromide (0.11 moles) and 150 mL of
1,2-dichloroethane were charged under an N.sub.2 atmosphere and
stirred. A solution of the intermediate product E (0.025 moles) and
triethylamine (0.25 moles) dissolved in 50 mL of 1,2-dichloroethane
was gradually added dropwise thereto. After completion of the
dropwise addition, the mixture was allowed to react at 70.degree.
C. for 5 hours. Thereafter, the reaction solution was filtered, and
the filtrate was subjected to liquid separation with 100 mL of
water 5 times. An organic phase was dehydrated over 5 g of sodium
sulfate, and the 1,2-dichloroethane was removed under reduced
pressure to obtain an intermediate product F (trimethylphosphine
body).
[0440] Subsequently, in a reaction apparatus equipped with a
stirring device and a dropping funnel, di-tert-butyl dicarbonate
(0.11 moles), N,N-dimethyl-4-aminopyridine (0.055 moles), and 150
mL of dichloromethane were charged under an N.sub.2 atmosphere and
stirred. 100 mL of dichloromethane having the intermediate product
F (0.025 moles) dissolved therein was gradually added dropwise
thereto. After the dropwise addition, the mixture was allowed to
react for 12 hours. Thereafter, the dichloromethane was removed,
and the obtained solid was purified to obtain a compound (CC1,
MW=516) represented by the following formula. A structure of CC1
was confirmed by means of NMR and IR.
##STR00018##
Examples 10 and 11
[0441] C1 and D1 were mixed in weight parts shown in Table 4 and
melt kneaded under a nitrogen atmosphere at a resin temperature of
200.degree. C. and at a rotation rate of 30 rpm for 2 minutes by
using a Labo Plasto mill (manufactured by Toyo Seiki Seisaku-Sho,
Ltd.), thereby obtaining a resin composition. The obtained resin
composition was subjected to a decomposition test in a 15%
hydrochloric acid aqueous solution at 100.degree. C. The test
results are shown in Table 4.
Examples 12 to 14
[0442] Resin compositions were prepared by mixing the components in
weight parts shown in Table 5 in the same manner as that in
Example, except that D1 was changed to D2 and D4, respectively, and
evaluated by the same method. The evaluation results were shown in
Table 5.
Comparative Example 10
[0443] C1 was used as it was and evaluated in the same method as
that in Example 1. The evaluation results are shown in Table 4.
Comparative Examples 11 to 12
[0444] Resin compositions were prepared by mixing the components in
weight parts shown in Table 3 in the same manner as that in Example
10, except that D1 was changed to D3 and D5, respectively, and
evaluated by the same method. The evaluation results were shown in
Table 4.
Examples 15 to 19 and Comparative Examples 13 to 15
[0445] Resin compositions in formations shown in Table 4 were
prepared in the same manners as those in Examples 10 to 14 and
Comparative Examples 10 to 12, respectively, except that the test
temperature was changed from 100.degree. C. to 120.degree. C., and
evaluated by the same method. The evaluation results were shown in
Table 4.
TABLE-US-00003 TABLE 3 Component D Evaluation D1 D2 D3 D4 D5
Reactivity with acidic group (%) 41.7 35.2 2.4 39.4 0 Judgement
.smallcircle. .smallcircle. x .smallcircle. x
TABLE-US-00004 TABLE 4 Compar- Compar- Compar- ative ative ative
Exam- Exam- Exam- Exam- Exam- Exam- Exam- Exam- ple 10 ple 10 ple
11 ple 12 ple 13 ple 11 ple 14 ple 12 Formulation Component C C1
100 98 95 98 95 95 95 95 (weight Component D D1 2 5 parts) D2 2 5
D3 5 D4 5 D5 5 Decomposition test temperature (.degree. C.) 100 100
100 100 100 100 100 100 Initial weight average molecular weight Mw0
149568 156769 165591 162644 162786 144627 140604 140309 Weight
average molecular 3 hours 24 96 106 78 86 56 75 16 weight retention
rate after 6 hours 7 90 104 74 92 39 59 Less than 2 decomposition
test in hydro- 12 hours Less than 2 61 94 66 88 Less than 2 34 Less
than 2 chloric acid aqueous solution (%) Weight of water-insoluble
matter after 0 0 0 1 5 0 2 0 48 hours of decomposition test in
hydro- chloric acid aqueous solution
TABLE-US-00005 TABLE 5 Compar- Compar- Compar- ative ative ative
Exam- Exam- Exam- Exam- Exam- Exam- Exam- Exam- ple 13 ple 15 ple
16 ple 17 ple 18 ple 14 ple 19 ple 15 Formulation Component C C1
100 98 95 98 95 95 95 95 (weight Component D D1 2 5 parts) D2 2 5
D3 5 D4 5 D5 5 Decomposition test temperature (.degree. C.) 120 120
120 120 120 120 120 120 Initial weight average molecular weight Mw0
149568 156769 165591 162644 162786 144627 140604 140309 Weight
average molecular 0.1 hours 39 94 98 80 87 52 80 32 weight
retention rate after 0.5 hours 14 81 92 58 80 23 64 12
decomposition test in hydro- 1 hour Less than 2 64 86 52 84 Less
than 2 55 Less than 2 chloric acid aqueous solution (%) Weight of
water-insoluble matter after 0 0 0 1 3 0 0 0 48 hours of
decomposition test in hydro- chloric acid aqueous solution
[0446] From these results, it is understood that in the case of
using, as the hydrolysis regulator, D1, D2, and D4, each satisfying
the reactivity with an acidic group, the resin composition can
realize the desired performance in hot water under a chemically
severe condition, such as an acidic or basic condition, etc.,
namely the performance in which after keeping the weight average
molecular weight of the resin composition and keeping the weight
and shape in hot water under a chemically severe condition, such as
an acidic or basic condition, etc., for a fixed period of time, the
resin is quickly decomposed.
[0447] In addition, it is understood that in the case of using D3
and D4, each of which does not satisfy the reactivity with an
acidic group, the decomposition of the resin composition is fast,
so that the satisfactory performance is not obtained.
* * * * *