U.S. patent application number 09/453325 was filed with the patent office on 2003-01-02 for production process and use for transparent heat-resistant resin.
Invention is credited to ASANO, HIDEO, FUJIOKA, KAZUMI.
Application Number | 20030004278 09/453325 |
Document ID | / |
Family ID | 26535693 |
Filed Date | 2003-01-02 |
United States Patent
Application |
20030004278 |
Kind Code |
A1 |
ASANO, HIDEO ; et
al. |
January 2, 2003 |
PRODUCTION PROCESS AND USE FOR TRANSPARENT HEAT-RESISTANT RESIN
Abstract
The present invention provides a production process for a
transparent heat-resistant resin, and further, a transparent
heat-resistant resin and uses therefor, wherein the production
process involves high dealcoholation conversion and a low content
of residual volatiles in the resultant resin, and therefore can
prevent foam or silver streak from occurring in the molded product,
and further, facilitates melt-molding such as injection molding,
and is fit for industrial production, and involves good efficiency.
The production process for a transparent heat-resistant resin
comprises the step of running a dealcoholation reaction of a
polymer having a hydroxyl group and an ester group in its molecular
chain to introduce a lactone ring structure into the polymer to
obtain a transparent resin having the heat resistance, and is
characterized in that the dealcoholation reaction is run in the
presence of a solvent, and further characterized by further
comprising a devolatilization step which is carried out jointly
with the dealcoholation reaction.
Inventors: |
ASANO, HIDEO; (OSAKA-SHI,
JP) ; FUJIOKA, KAZUMI; (IBO-GUN, JP) |
Correspondence
Address: |
HAUGEN LAW FIRM PLLP
1130 TCF TOWER
121 SOUTH EIGHTH STREET
MINNEAPOLIS
MN
55402
US
|
Family ID: |
26535693 |
Appl. No.: |
09/453325 |
Filed: |
December 2, 1999 |
Current U.S.
Class: |
525/330.6 ;
428/487; 428/501; 428/503 |
Current CPC
Class: |
Y10T 428/31859 20150401;
C08F 8/16 20130101; Y10T 428/31866 20150401; Y10T 428/31812
20150401 |
Class at
Publication: |
525/330.6 ;
428/501; 428/503; 428/487 |
International
Class: |
C08F 120/10 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 9, 1998 |
JP |
10-350338 |
Aug 27, 1999 |
JP |
11-242272 |
Claims
What is claimed is:
1. A production process for a transparent heat-resistant resin,
comprising the step of running a dealcoholation reaction of a
polymer having a hydroxyl group and an ester group in its molecular
chain to introduce a lactone ring structure into the polymer to
obtain a transparent resin having the heat resistance, with the
production process being characterized in that the dealcoholation
reaction is run in the presence of a solvent, and further
characterized by further comprising a devolatilization step which
is carried out jointly with the dealcoholation reaction.
2. A production process according to claim 1, wherein the
devolatilization step is initiated at an interval after the
dealcoholation reaction has been initiated.
3. A production process according to claim 2, wherein the
conversion of the dealcoholation reaction is not lower than 60 %
when the f flization step has been initiated.
4. A production process according to claim 1, wherein the
dealcoholation reaction is run with a vessel type reactor.
5. A production process according to claim 1, wherein the
dealcoholation reaction is run using an organophosphorus compound
as a catalyst.
6. A production process according to claim 5, wherein the
organophosphorus compound is at least one member selected from the
group consisting of alkyl(aryl)phosphonous acids (which may be
their tautomers, namely, alkyl(aryl)phosphinic acids), phosphate
diesters or monoesters, phosphate diesters or monoesters, and
alkyl(aryl)phosphonic acids.
7. A transparent heat-resistant resin, which is obtained by a
process including the step of running a dealcoholation reaction of
a polymer having a hydroxyl group and an ester group in its
molecular chain to introduce a lactone ring structure into the
polymer, with the transparent heat-resistant resin being
characterized by having a dealcoholation conversion of not lower
than 90% as determined from a weight loss between 150 and
300.degree. C. in dynamic TG measurement.
8. A transparent heat-resistant resin, which is obtained by a
process including the step of running a dealcoholation reaction of
a polymer having a hydroxyl group and an ester group in its
molecular chain to introduce a lactone ring structure into the
polymer, with the transparent heat-resistant resin being
characterized by having a yellowness index (YI) of not more than 6
in a 15 weight % chloroform solution.
9. A transparent heat-resistant resin, which is obtained by a
process including the step of running a dealcoholation reaction of
a polymer having a hydroxyl group and an ester group in its
molecular chain to introduce a lactone ring structure into the
polymer, with the transparent heat-resistant resin being
characterized by having a weight-average molecular weight of
40,000.about.300,000.
10. A transparent heat-resistant resin, which is obtained by a
process including the step of running a dealcoholation reaction of
a polymer having a hydroxyl group and an ester group in its
molecular chain to introduce a lactone ring structure into the
polymer, with the transparent heat-resistant resin being
characterized in that a molded product by injection molding of the
transparent heat-resistant resin has a total luminous transmittance
of not lower than 85%.
11. A transparent heat-resistant resin, which is obtained by a
process including the step of running a dealcoholation reaction of
a polymer having a hydroxyl group and an ester group in its
molecular chain to introduce a lactone ring structure into the
polymer, with the transparent heat-resistant resin being
characterized in that a molded product by injection molding of the
transparent heat-resistant resin has a haze value of not higher
than 5%.
12. A transparent heat-resistant resin molding material, comprising
the transparent heat-resistant resin as recited in claim 7.
13. A transparent heat-resistant resin molding material, comprising
the transparent heat-resistant resin as recited in claim 8.
14. A molded product, which is obtained by a process including the
step of molding a transparent heat-resistant resin molding material
that includes the transparent heat-resistant resin as recited in
claim 7.
15. A molded product, which is obtained by a process including the
step of molding a transparent heat-resistant resin molding material
that includes the transparent heat-resistant resin as recited in
claim 8.
Description
BACKGROUND OF THE INVENTION
[0001] 1. A. Technical Field
[0002] The present invention relates to a production process and a
use for a transparent heat-resistant resin, more particularly, to a
production process and a use for a transparent heat-resistant
resin, which process is characterized by involving a specific
heating vacuum treatment.
[0003] 1. B. Background Art
[0004] A methacrylic resin is excellent in transparency, surface
gloss, and weather resistance and is well-balanced with regard to
mechanical strength, molding processibility, and surface hardness,
so the methacrylic resin is widely used for optical purposes of
cars, home use electric appliances, and so on. However, the glass
transition temperature (Tg) of the methacrylic resin is around
110.degree. C. and is therefore difficult to use in fields where
the heat resistance is demanded. On the other hand, light sources
are often designed to be put in the vicinity of the resin to meet
requests for the freedom degree of the design, the achievement of
the compactness and high performance, and so on. Thus, a more
excellent heat-resistant resin is desired.
[0005] Polym. Prepr., 8, 1, 576 (1967) discloses a process for
obtaining a methacrylic resin having the heat resistance, in which
process an alkyl 2-(hydroxymethyl)acrylate/methyl methacrylate
copolymer or an .alpha.-hydroxymethylstyrene/methyl methacrylate
copolymer is allowed to run a dealcoholation reaction by heating
under vacuum with an extruder to form a lactone ring due to
condensation of hydroxyl group and ester group of the polymer, thus
obtaining the heat-resistant resin. In this process, solution
polymerization or bulk polymerization is carried out. In the case
of the solution polymerization, the resultant polymer is separated
in the form of a solid from polymerization reaction products, and
then introduced into the extruder. In the case of the bulk
polymerization, the solid polymer resultant from the polymerization
is granulated without modification, and then introduced into the
extruder. Therefore, this process is unfit for industrial
production. Furthermore, in this process, when the content of the
alkyl 2-(hydroxymethyl)acrylate or .alpha.-hydroxymethylstyrene is
increased, the resultant conversion of the dealcoholation reaction
is low. As is seen in the case of the
.alpha.-hydroxymethylstyrene/methyl methacrylate copolymer, for
example, when the content of .alpha.-hydroxymethylstyrene in the
polymer is 25%, the conversion of the dealcoholation reaction is
71%, and when the content of .alpha.-hydroxymethylstyrene in the
polymer is 30%, the conversion is 59%. Therefore, there are
demerits, for example, in that when the resultant polymer is
re-shaped by heating, the dealcoholation reaction proceeds to cause
the molded product to foam. Another problem is that the production
process is complicated because the solid polymer is transferred, or
introduced into the extruder.
[0006] JP-A-09-241323 discloses another prior art in which, if
poly[ethyl 2-hydroxymethyl)acrylate], poly[alkyl
2-(hydroxymethyl)acrylate], or a polymer having a high content of
ethyl 2-(hydroxymethyl)acrylate or alkyl 2-(hydroxymethyl)acrylate
is used in a solid state in its dealcoholation reaction, then the
polymer is crosslinked in the reaction to make melt-molding
difficult, therefore the dealcoholation is carried out in a
solution state as made by: once obtaining the polymer in a solid
state by reprecipitation, and then re-dissolving the resultant
polymer into dimethyl sulfoxide (DMSO). However, this process needs
the steps of the reprecipitation, the separation of the resultant
solid, and the re-dissolution of this solid, and is therefore unfit
for industrial production. In addition, also as to this process,
the dealcoholation conversion is so insufficient that it is
necessary to keep high temperature for a certain time in order to
further advance the reaction in the molding step such as press
molding, or that it is necessary to run the reaction in a solution
for a long time in order to increase the dealcoholation conversion.
Furthermore, this process needs a step of removing the solvent
again because the resin as obtained by the dealcoholation reaction
is in a solution state. In addition, even if a dealcoholation
conversion near 90% can be achieved, and even if the resultant
resin provides results satisfactory in some degree with regard to
the heat-resistance of the resin, there is still a great demerit in
that foam or silver streak occurs in the molded product due to
heating in the molding step.
SUMMARY OF THE INVENTION
A. Object of the Invention
[0007] An object of the present invention is to provide a
production process for a transparent heat-resistant resin, and
further, a transparent heat-resistant resin and uses therefor,
wherein the production process involves high dealcoholation
conversion and a low content of residual volatiles in the resultant
resin, and therefore can prevent foam or silver streak from
occurring in the molded product, and further, facilitates
melt-molding such as injection molding, and is fit for industrial
production, and involves good efficiency.
B. Disclosure of the Invention
[0008] The present inventors diligently studied to solve the above
problems, and as a result, found that the above problems could be
all solved if a process comprising the step of running a
dealcoholation reaction of a polymer having a hydroxyl group and an
ester group in its molecular chain to introduce a lactone ring
structure into the polymer to obtain a transparent resin having the
heat resistance further comprises the step of running the
dealcoholation reaction and a devolatilization treatment
simultaneously with each other in the presence of a solvent.
[0009] That is to say, a production process for a transparent
heat-resistant resin, according to the present invention, comprises
the step of running a dealcoholation reaction of a polymer having a
hydroxyl group and an ester group in its molecular chain to
introduce a lactone ring structure into the polymer to obtain a
transparent resin having the heat resistance, and is characterized
in that the dealcoholation reaction is run in the presence of a
solvent, and further characterized by further comprising a
devolatilization step which is carried out jointly with the
dealcoholation reaction.
[0010] In addition, a transparent heat-resistant resin, according
to the present invention, is obtained by a process including the
step of running a dealcoholation reaction of a polymer having a
hydroxyl group and an ester group in its molecular chain to
introduce a lactone ring structure into the polymer, and is
characterized by having a dealcoholation conversion of not lower
than 90% as determined from a weight loss between 150 and
300.degree. C. in dynamic TG measurement. Furthermore, a
transparent heat-resistant resin molding material, according to the
present invention, is characterized by comprising this transparent
heat-resistant resin according to the present invention. If this
transparent heat-resistant resin molding material according to the
present invention is molded, a molded product according to the
present invention is obtained.
[0011] Another transparent heat-resistant resin, according to the
present invention, is obtained by a process including the step of
running a dealcoholation reaction of a polymer having a hydroxyl
group and an ester group in its molecular chain to introduce a
lactone ring structure into the polymer, and is characterized by
having a yellowness index (YI) of not more than 6 in a 15 weight %
chloroform solution. Furthermore, another transparent
heat-resistant resin molding material, according to the present
invention, is characterized by comprising this transparent
heat-resistant resin according to the present invention. If this
transparent heat-resistant resin molding material according to the
present invention is molded, another molded product according to
the present invention is obtained.
[0012] Yet another transparent heat-resistant resin, according to
the present invention, is obtained by a process including the step
of running a dealcoholation reaction of a polymer having a hydroxyl
group and an ester group in its molecular chain to introduce a
lactone ring structure into the polymer, and is characterized by
having a weight-average molecular weight of
40,000.about.300,000.
[0013] Yet another transparent heat-resistant resin, according to
the present invention, is obtained by a process including the step
of running a dealcoholation reaction of a polymer having a hydroxyl
group and an ester group in its molecular chain to introduce a
lactone ring structure into the polymer, and is characterized in
that a molded product by injection molding of the transparent
heat-resistant resin has a total luminous transmittance of not
lower than 85 %.
[0014] Yet another transparent heat-resistant resin, according to
the present invention, is obtained by a process including the step
of running a dealcoholation reaction of a polymer having a hydroxyl
group and an ester group in its molecular chain to introduce a
lactone ring structure into the polymer, and is characterized in
that a molded product by injection molding of the transparent
heat-resistant resin has a haze value of not higher than 5%.
[0015] These and other objects and the advantages of the present
invention will be more fully apparent from the following detailed
disclosure.
DETAILED DESCRIPTION OF THE INVENTION
[0016] (Raw Polymer):
[0017] In the production process for a transparent heat-resistant
resin, according to the present invention, the resin is obtained
using the polymer having a hydroxyl group and an ester group in its
molecular chain as a raw material.
[0018] The polymer having a hydroxyl group and an ester group in
its molecular chain is a polymer having a hydroxyl group and an
ester group which are bonded to the principal chain directly or
through some atoms, and this polymer is to involve condensation
cyclization of at least part of the above hydroxyl group and ester
group due to the dealcoholation reaction to form a lactone ring.
Especially, the case where the above hydroxyl group and the above
ester group are present in the vicinity of each other has the
advantage of easily forming the lactone ring, and thus, it is more
preferable that the number of the atoms which are present between
the hydroxyl group and the ester group is not larger than 6, most
preferably not larger than 4. In the case where this number is
larger than 6 there are disadvantages in that crosslinking due to
an intermolecular reaction occurs to facilitate gelation. The
molecular weight of this polymer is not especially limited, but the
weight-average molecular weight is preferably in the range of
1,000.about.1,000,000, particularly, more preferably
5,000.about.500,000, still more preferably 40,000.about.300,000. In
the case where the molecular weight is lower than the above range,
there is a problem in that the resultant product has so low
mechanical strength as to be brittle. In the case where the
molecular weight is higher than the above range, there is a problem
in that the resultant product has so low fluidity as to be
difficult to mold.
[0019] As to the content of the hydroxyl group and the ester group
in the molecular chain of the transparent heat-resistant resin
according to the present invention, for example, when a
2-(hydroxyalkyl)acrylate ester is a raw monomer, the content of the
2-(hydroxyalkyl)acrylate ester monomer in the polymer is preferably
in the range of 5.about.60 weight %, more preferably 10.about.60
weight %, still more preferably 20.about.50 weight %, and
particularly preferably 20.about.40 weight %. When the polymer is
obtained from monomers having a hydroxyl group and an ester group
separately or includes repeating units of such monomers, the above
content is represented by the content of a monomer having a
hydroxyl group or ester group, of whichever the equivalent is
smaller, or by the content of a repeating unit of such a monomer.
In the case where the content of the hydroxyl group and the ester
group is low, the heat resistance or solvent resistance of the
polymer resultant from the dealcoholation is not enhanced very
much. In the case where the content of the hydroxyl group and the
ester group is too high, for example, exceeds 60 weight %, the
polymer might be crosslinked to make melt-molding difficult, or the
dealcoholation conversion might be so low that the molded product
might easily foam.
[0020] In the present invention, the above polymer is introduced
into the below-mentioned step of the dealcoholation reaction and
devolatilization in the presence of a solvent. The solvent, as used
in this step, is not especially limited, but it is economically
preferable to use the solvent without being entirely removed after
being used for the polymerization reaction to obtain the polymer.
For example, solvents which are used for conventional radical
polymerization reactions are selected, and examples thereof
include: aromatic hydrocarbons such as toluene, xylene, and
ethylbenzene; ketones such as methyl ethyl ketone and methyl
isobutyl ketone; and chloroform, DMSO, and tetrahydrofuran. In
addition, considering that the use of a solvent having too high
boiling point would result in a high content of residual volatiles
in the resultant resin after devolatilization, solvents which
dissolve the polymer at treatment temperature and have a boiling
point of 50.about.200.degree. C. are preferable. More preferable
examples thereof include aromatic hydrocarbons such as toluene and
ketones such as methyl ethyl ketone.
[0021] Incidentally, as is mentioned below, the aforementioned
polymer, for example, can be obtained not only by a process
including the step of polymerizing raw monomers, at least part of
which is a monomer having a hydroxyl group and an ester group or a
mixture of a monomer having a hydroxyl group and a monomer having
an ester group, but also by a process including the step of
post-introducing the hydroxyl group or ester group into the
polymer, for example, by utilizing the following reactions: an
addition reaction of a hydroxyl group to a double-bond portion of a
copolymer of a diene compound such as butadiene; hydrolysis of a
polymer having an ester group, such as a vinyl acetate copolymer;
and esterification of a polymer having a carboxyl group or acid
anhydride group.
[0022] (Monomer as Raw Material of Polymer):
[0023] The monomer, which is a raw material of the aforementioned
polymer having a hydroxyl group and an ester group in its molecular
chain, is not especially limited, but it is particularly preferable
that at least part of the raw materials is a vinyl monomer having a
hydroxyl group and an ester group in its molecule or a mixture of a
vinyl monomer having a hydroxyl group in its molecule and a vinyl
monomer having an ester group in its molecule. Other vinyl monomers
are permitted to coexist with the above vinyl monomers.
[0024] The vinyl monomer having a hydroxyl group and an ester group
in its molecule is not especially limited, but monomers of general
formula (1) below are particularly preferable, of which examples
include methyl 2-(hydroxymethyl)acrylate, ethyl
2-(hydroxymethyl)acrylate, isopropyl 2-(hydroxymethyl)acrylate,
n-butyl 2-(hydroxymethyl)acrylate, and t-butyl
2-(hydroxymethyl)acrylate. Among them, methyl
2-(hydroxymethyl)acrylate and ethyl 2-(hydroxymethyl)acrylate are
particularly preferable, and further, methyl
2-(hydroxymethyl)acrylate is most preferable because it has the
highest effect to enhance the heat resistance. The above monomers
may be used either alone respectively or in combinations with each
other. 1
[0025] wherein R.sub.1 and R.sub.2 are the same as or different
from each other and denote a hydrogen atom or an organic
residue.
[0026] The aforementioned vinyl monomer having a hydroxyl group in
its molecule is not especially limited, but examples thereof
include: monomers of general formula (1) above;
.alpha.-hydroxymethylstyrene; .alpha.-hydroxyethykstyrene;
2-(hydroxyalkyl) acrylate esters such as methyl
2-(hydroxyethyl)acrylic and 2-(hydroxyalkyl) acrylic acids such as
2-(hydroxyethyl)acrylic acid. These may be used either alone
respectively or in combinations with each other. Among them, the
monomers of general formula (1) above are preferable, because the
use thereof prevents the gelation from occurring due to a
crosslinking reaction even if the dealcoholation conversion, that
is, the lactonization conversion, is enhanced.
[0027] The aforementioned vinyl monomer having an ester group in
its molecule is not especially limited, but examples thereof
include: monomers of general formula (1) above; acrylate esters
such as methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl
acrylate, t-butyl acrylate, cyclohexyl acrylate, and benzyl
acrylate; and methacrylate esters such as methyl methacrylate,
ethyl methacrylate, propyl methacrylate, n-butyl methacrylate,
isobutyl methacrylate, t-butyl methacrylate, cyclohexyl
methacrylate, and benzyl methacrylate. These may be used either
alone respectively or in combinations with each other. Among them,
methyl methacrylate is preferable in respect to the heat resistance
and the transparency.
[0028] The other monomers, which may be jointly used with the above
vinyl monomer having a hydroxyl group and an ester group in its
molecule or with the above mixture of the vinyl monomer having a
hydroxyl group in its molecule and the vinyl monomer having an
ester group in its molecule, are not especially limited, but
monomers of general formula (2) below and monomers such as
N-substituted maleimides are particularly preferable, of which
examples include styrene, .alpha.-methylstyrene, acrylonitrile,
methyl vinyl ketone, ethylene, propylene, and vinyl acetate. Among
them, styrene and .alpha.-methylstyrene are particularly
preferable. In addition, the above monomers may be used either
alone respectively or in combinations with each other. In addition,
the content of the above monomers, which may further be used, is
preferably not higher than 30 weight %, more preferably not higher
than 20 weight %, still more preferably not higher than 10 weight
%. 2
[0029] wherein: R.sub.3 denotes a hydrogen atom or a methyl group;
and X denotes a hydrogen atom, an alkyl group with 1 to 6 carbon
atoms, an aryl group, an --OAc group, a --CN group, or a --COR
.sub.0 group, wherein R.sub.0 denotes a hydrogen atom or an organic
residue.
[0030] (Polymerization Reaction):
[0031] The method of the polymerization reaction to obtain the
aforementioned polymer, as used in the production process according
to the present invention, from the aforementioned monomers is not
especially limited, but solution polymerization or bulk
polymerization is preferable. Furthermore, in the present
invention, because, as is mentioned below, the dealcoholation
reaction needs to be run in the presence of a solvent, the solution
polymerization is particularly preferable. In addition, as to the
bulk polymerization, the solvent may be added after the
polymerization, if necessary. Regardless of the polymerization
method, if necessary, after once separating the resultant polymer
in the form of a solid, the solvent may be added thereto.
Furthermore, as to the bulk polymerization, the resultant reaction
mixture may be in a solution state due to the presence of monomers
remaining unreacted. The polymerization temperature and the
polymerization time are different according to factors such as
sorts and ratios of polymerizable monomers as used, but,
preferably, the polymerization temperature is in the range of
0.about.150.degree. C., and the polymerization time is in the range
of 0.5.about.20 hours, and more preferably, the polymerization
temperature is in the range of 80.about.140.degree. C., and the
polymerization time is in the range of 1.about.10 hours.
[0032] When the polymerization reaction is run by the solution
polymerization, the solvent as used is not especially limited, but,
for example, solvents which are used for conventional radical
polymerization reactions are selected, and examples thereof
include: aromatic hydrocarbons such as toluene, xylene, and
ethylbenzene; ketones such as methyl ethyl ketone and methyl
isobutyl ketone; and chloroform, DMSO, and tetrahydrofuran. In
addition, considering that the use of a solvent having too high
boiling point would result in a high content of residual volatiles
in the resultant resin after devolatilization, solvents which
dissolve the polymer at treatment temperature and have a boiling
point of 50.about.200.degree. C. are preferable. More preferable
examples thereof include aromatic hydrocarbons such as toluene and
ketones such as methyl ethyl ketone.
[0033] In the polymerization reaction, an initiator may be added,
if necessary. The initiator is not especially limited, but examples
thereof include: organic peroxides such as cumene hydroperoxide,
diisopropylbenzene hydroperoxide, di-t-butyl peroxide, lauroyl
peroxide, benzoyl peroxide, t-butyl peroxyisopropyl carbonate, and
t-amyl peroxy-2-ethylhexonoate; and azo compounds such as
2,2'-azobis(isobutyronitrile), 1,1'-azobis(cyclohexan
ecarbonitrile), and 2,2'-a zobis(2,4-dimethylvaleronitrile). These
may be used either alone respectively or in combinations with each
other. Incidentally, the amount of the initiator as used may fitly
be set according to factors such as combinations of monomers as
used and reaction conditions, therefore, is not especially
limited.
[0034] The polymerization reaction mixture, resultant from the
above polymerization reaction, contains the solvent as well as the
resultant polymer. However, in the production process according to
the present invention, it is not necessary to entirely remove this
solvent to separate the polymer in a solid state. Therefore,
preferably, the polymer is introduced into the subsequent step in a
state of containing the solvent. In addition, after separating the
polymer in a solid state, a solvent which is favorable for the
subsequent step may be re-added thereto, if necessary. The amount
of the solvent is in the range of usually 5.about.90 weight %,
preferably 10.about.80 weight %, more preferably 30.about.75 weight
%, of the entirety. In the case where the amount is smaller than 5
weight %, the polymer has so high viscosity as to be difficult to
handle. In the case where the amount exceeds 90 weight %, the
amount of solvent to be devolatilized is too large, therefore the
productivity is low.
[0035] (Production Process for Transparent Heat-resistant
Resin):
[0036] The production process for a transparent heat-resistant
resin, according to the present invention, comprises the step of
running a dealcoholation reaction of a polymer having a hydroxyl
group and an ester group in its molecular chain to introduce a
lactone ring structure into the polymer to obtain a transparent
resin having the heat resistance, and is characterized in that the
dealcoholation reaction is run in the presence of a solvent, and
further characterized by further comprising a devolatilization step
which is carried out jointly with the dealcoholation reaction.
[0037] The dealcoholation reaction in the present invention is a
reaction which involves condensation cyclization of at least part
of the hydroxyl group and ester group in the molecular chain of the
aforementioned polymer due to heating to form a lactone ring,
wherein the condensation cyclization involves formation of an
alcohol as a by-product. The formation of this lactone ring
structure in the molecular chain gives high heat resistance. In the
case where the conversion of the above dealcoholation reaction is
insufficient, there are disadvantages in that the heat resistance
might not sufficiently be enhanced, or in that the dealcoholation
occurs in the molding step due to the heating treatment in the
molding step to result in the presence of the resultant alcohol in
the form of foam or silver streak in the molded product.
[0038] On the other hand, the devolatilization step in the present
invention is a treatment step in which volatiles, such as solvents
and residual monomers, and the alcohol, as formed as a by-product
from the above dealcoholation reaction, are removed (under vacuum
heating conditions, if necessary). In the case where this treatment
step is insufficient, the content of residual volatiles in the
resultant resin is so large that the resin becomes colored due to
factors such as deterioration in the molding step, or that there
occur, for example, problems of molding defects such as foam or
silver streak.
[0039] In the production process according to the present
invention, it is necessary that the aforementioned dealcoholation
reaction is run in the presence of a solvent, when the
aforementioned devolatilization step is jointly carried out. This
is one of the characteristics of the present invention. Running the
dealcoholation reaction in the presence of a solvent can overcome
the demerit of the low conversion as seen when running the
dealcoholation reaction in a solid state. As a result, high
conversion can be realized. In addition, in this process, because
the alcohol as formed as a by-product in the dealcoholation
reaction is removed by forcible devolatilization, the equilibrium
of the reaction moves to the product side, with the result that the
high conversion can be achieved in a considerably shorter time than
conventional cases. Furthermore, because the dealcoholation
reaction and the devolatilization step are jointly carried out, the
cost down of the process can also be achieved. Particularly, it is
preferable that the aforementioned step is carried out in a
solution state. In addition, when the present invention is, for
example, applied to the monomer having the specific structure of
general formula (1), the dealcoholation conversion is enhanced, in
other words, the lactone cyclization conversion is enhanced, so
this is a very excellent treatment step. In addition, the heat
resistance and the moldability of the resultant resin are more
excellent than those of lactone-ring-containing substances as
obtained by conventional known processes.
[0040] In the present invention, the dealcoholation conversion, as
determined from a weight loss between 150 and 300.degree. C. in
dynamic TG measurement, is preferably not lower than 90%, more
preferably not lower than 95%, still more preferably not lower than
97%, at the end of the dealcoholation reaction.
[0041] The content of residual volatiles in the transparent
heat-resistant resin, as obtained by the production process
according to the present invention, is preferably not higher than
1,500 ppm, more preferably not higher than 1,000 ppm. In the case
where the content is higher than these ranges, molding defects are
caused, such as coloring (due to factors such as deterioration in
the molding step), foam, or silver streak.
[0042] When running the above dealcoholation reaction, other
thermoplastic resins may be caused to coexist with the
aforementioned polymer having a hydroxyl group and an ester group
in its molecular chain.
[0043] When running the above dealcoholation reaction, an
esterification or transesterification catalyst which is
conventionally used such as p-tolunesulfonic acid may be used as a
catalyst of the dealcoholation reaction, if necessary. In the
production process according to the present invention, however, it
is preferable to use an organophosphorus compound as the catalyst.
These catalysts may be added at the beginning and/or on the way of
the reaction.
[0044] If the organophosphorus compound is used as the
aforementioned catalyst, not only can the dealcoholation conversion
be enhanced, but also coloring of the resultant resin can greatly
be reduced. Moreover, the use of such a catalyst can prevent the
molecular weight of the resultant resin from lowering in the
devolatilization step, and further, can give excellent mechanical
strength.
[0045] Examples of the organophosphorus compound, usable as a
catalyst when carrying out the dealcoholation reaction,
include:
[0046] alkyl(aryl)phosphonous acids (which may be their tautomers,
namely, alkyl(aryl)phosphinic acids) such as methylphosphonous
acid, ethylphosphonous acid, and phenylphosphonous acid, and their
diesters or monoesters;
[0047] dialkyl(aryl)phosphinic acids such as dimethylphosphinic
acid, diethylphosphinic acid, diphenylphosphinic acid,
phenylmethylphosphinic acid, and phenylethylphosphinic acid, and
their esters;
[0048] alkyl(aryl)phosphonic acids such as methylphosphonic acid,
ethylphosphonic acid, trifluoromethylphosphonic acid, and
phenylphosphonic acid, and their diesters or monoesters;
[0049] alkyl(aryl)phosphinous acids such as methylphosphinous acid,
ethylphosphinous acid, and phenylphosphinous acid, and their
esters;
[0050] phosphite diesters or monoesters or triesters, such as
methyl phosphite, ethyl phosphite, phenyl phosphite, dimethyl
phosphite, diethyl phosphite, diphenyl phosphite, trimethyl
phosphite, triethyl phosphite, and triphenyl phosphite;
[0051] phosphate diesters or monoesters or triesters, such as
methyl phosphate, ethyl phosphate, 2-ethylhexyl phosphate, phenyl
phosphate, dimethyl phosphate, diethyl phosphate, di-2-ethylhexyl
phosphate, diphenyl phosphate, trimethyl phosphate, triethyl
phosphate, and triphenyl phosphate;
[0052] mono-, di-, or trialkyl(aryl)phosphines such as
methylphosphine, ethylphosphine, phenylphosphine,
dimethylphosphine, diethylphosphine, diphenylphosphine,
trimethylphosphine, triethylphosphine, and triphenylphosphine;
[0053] alkyl(aryl)halogenphosphines such as
methyldichlorophosphine, ethyldichlorophosphine,
phenyldichlorophosphine, dimethylchlorophosphine,
diethylchlorophosphine, and diphenylchlorophosphine;
[0054] mono-, di-, or trialkyl(aryl)phosphine oxides such as
methylphosphine oxide, ethylphosphine oxide, phenylphosphine oxide,
dimethylphosphine oxide, diethylphosphine oxide, diphenylphosphine
oxide, trimethylphosphine oxide, triethylphosphine oxide, and
triphenylphosphine oxide;
[0055] tetraalkyl(aryl)phosphonium halides such as
tetramethylphosphonium chloride, tetraethylphosphonium chloride,
and tetraphenylphosphonium chloride.
[0056] Among them, the alkyl(aryl)phosphonous acids, the phosphite
diesters or monoesters, the phosphate diesters or monoesters, and
the alkyl(aryl)phosphonic acids are particularly preferable, and
further, the alkyl(aryl)phosphonous acids, the phosphite diesters
or monoesters, and the phosphate diesters or monoesters are more
preferable in respect to high catalytic activity and low coloring
property. Among them, the alkyl(aryl)phosphonous acids and the
phosphate diesters or monoesters are particularly preferable. The
organophosphorus compounds may be used either alone respectively or
in combinations with each other.
[0057] The amount of the catalyst, usable for the dealcoholation
reaction, is not especially limited, but is preferably in the range
of 0.001.about.10 weight %, more preferably 0.01.about.5 weight %,
still more preferably 0.01.about.2.5 weight %, yet still more
preferably 0.05.about.1 weight %, of the raw polymer. In the case
where the amount of the catalyst as used is smaller than 0.001
weight %, there are disadvantages in that the dealcoholation
conversion could not sufficiently be enhanced. On the other hand,
in the case where the amount of the catalyst as used is larger than
10 weight %, there are disadvantages in that the catalyst causes
coloring, or the polymer is crosslinked to make melt-molding
difficult. Incidentally, the timing to add the catalyst is not
especially limited, and for example, the catalyst may be added at
the beginning and/or on the way of the reaction.
[0058] In the production process according to the present
invention, it is necessary that the aforementioned dealcoholation
reaction is run in the presence of a solvent, when the
aforementioned devolatilization step is jointly carried out.
Examples of embodiments thereof include an embodiment in which the
devolatilization step is jointly carried out throughout the
dealcoholation reaction, and further, an embodiment in which the
devolatilization step is jointly carried out not throughout the
dealcoholation reaction, but only for part of the duration of the
dealcoholation reaction.
[0059] As to the embodiment in which the devolatilization step is
jointly carried out throughout the dealcoholation reaction, the
device as used therefor is not especially limited, but, for
carrying out the present invention more effectively, it is
preferable to use a devolatilizer comprising a heat exchanger and a
devolatilization vessel, or an extruder with vents, or a device
comprising the above devolatilizer and the above extruder which are
arranged tandem. Furthermore, it is more preferable to use either
the devolatilizer comprising a heat exchanger and a
devolatilization vessel, or the extruder with vents.
[0060] When the above devolatilizer comprising a heat exchanger and
a devolatilization vessel is used, the reaction and treatment
temperature is preferably in the range of 150.about.350.degree. C.,
more preferably 200.about.300.degree. C. In the case where the
above temperature is lower than 150.degree. C., there are
unfavorable problems in that the dealcoholation reaction is
insufficient, or in that the residual volatile content is high. In
the case where the temperature is higher than 350.degree. C., there
are unfavorable problems in that coloring or decomposition occurs.
The pressure in the reaction and treatment is preferably in the
range of 931.about.1.33 hPa (700.about.1 mmHg), more preferably
798.about.66.5 hPa (600.about.50 mmHg). In the case where the above
pressure is higher than 931 hPa, there are unfavorable problems in
that the volatiles including the alcohol tend to remain. In the
case where the pressure is lower than 1.33 hPa, there are
unfavorable problems in that it becomes difficult to industrially
carry out the present invention.
[0061] In addition, when the aforementioned extruder with vents is
used, the number of the vents may be either one or more, but it is
preferable that the extruder has more than one vent. The reaction
and treatment temperature in the extruder with vents is preferably
in the range of 150.about.350.degree. C., more preferably
200.about.300.degree. C. In the case where the above temperature is
lower than 150.degree. C., there are unfavorable problems in that
the dealcoholation reaction is insufficient, or in that the
residual volatile content is high. In the case where the
temperature is higher than 350.degree. C., there are unfavorable
problems in that coloring or decomposition occurs. The pressure in
the reaction and treatment is preferably in the range of
931.about.1.33 hPa (700.about.1 mmHg), more preferably
798.about.13.3 hPa (600.about.10 mmHg). In the case where the above
pressure is higher than 931 hPa, there are unfavorable problems in
that the volatiles including the alcohol tend to remain. In the
case where the pressure is lower than 1.33 hPa, there are
unfavorable problems in that it becomes difficult to industrially
carry out the present invention.
[0062] Incidentally, as is mentioned below, as to the embodiment in
which the devolatilization step is jointly carried out throughout
the dealcoholation reaction, there is a possibility that the
properties of the resultant resin might be deteriorated under
severe heating treatment conditions. Therefore, for example, it is
preferable that the aforementioned catalyst of the dealcoholation
reaction is used to run the reaction under as mild conditions as
possible, for example, utilizing the extruder with vents.
[0063] In the aforementioned embodiment in which the
devolatilization step is jointly carried out throughout the
dealcoholation reaction, the polymer having a hydroxyl group and an
ester group in its molecular chain resultant from the
aforementioned polymerization reaction is introduced into the above
reactor system along with the solvent. In this case, the polymer
may be caused to pass through the above reactor system such as
extruder with vents once more, if necessary.
[0064] As to another embodiment of the production process according
to the present invention, there is the embodiment in which the
devolatilization step is jointly carried out not throughout the
dealcoholation reaction, but only for part of the duration of the
dealcoholation reaction. Examples thereof include an embodiment in
which the dealcoholation reaction is allowed to preliminarily run
in some degree by further heating a device which has been used to
produce the polymer having a hydroxyl group and an ester group in
its molecular chain, and further, if necessary, by partly jointly
carrying out the devolatilization step, and thereafter, the
aforementioned dealcoholation reaction in which the
devolatilization step is carried out jointly and simultaneously
therewith is run to complete the reaction.
[0065] As to the aforementioned embodiment in which the
devolatilization step is jointly carried out throughout the
dealcoholation reaction, for example, the alkyl
2-(hydroxymethyl)acrylate copolymer, which is a raw polymer to form
the transparent heat-resistant resin according to the present
invention, is heated at high temperature near 250.degree. C. or at
higher temperature with a twin-screw extruder, when partial
decomposition for example might occur before the dealcoholation
reaction according to differences of thermal hysteresis, with the
result that the properties of the resultant resin might be
deteriorated. Thus, the above embodiment, in which the
dealcoholation reaction is allowed to preliminarily run in some
degree before the dealcoholation reaction in which the
devolatilization step is carried out jointly and simultaneously
therewith is run, is a preferable embodiment because the reaction
conditions in the latter half can be made so mild that the
deterioration of the properties can be prevented. Examples of
particularly preferable embodiments include an embodiment in which
the devolatilization step is initiated at an interval after the
dealcoholation reaction has been initiated, namely, an embodiment
in which the dealcoholation reaction of at least part of the
hydroxyl group and ester group in the molecular chain of the
polymer resultant from the polymerization reaction is preliminarily
run to increase the dealcoholation conversion in some degree, and
thereafter the dealcoholation reaction in which the
devolatilization step is carried out jointly and simultaneously
therewith is run. Specifically, for example, an embodiment is
preferable in which the dealcoholation reaction is allowed to
preliminarily run to some degree of conversion in the presence of a
solvent with a vessel type reactor, and thereafter the
dealcoholation reaction is completed with a device, for example, a
reactor having a devolatilizer such as a devolatilizer comprising a
heat exchanger and a devolatilization vessel, or an extruder with
vents. Especially, in this case, it is more preferable that the
catalyst for the dealcoholation reaction is present.
[0066] The above process, in which the dealcoholation reaction of
at least part of the hydroxyl group and ester group in the
molecular chain of the polymer resultant from the polymerization
reaction is preliminarily run to increase the dealcoholation
conversion in some degree, and thereafter the dealcoholation
reaction in which the devolatilization step is carried out jointly
and simultaneously therewith is run, is a preferable embodiment for
obtaining the transparent heat-resistant resin according to the
present invention. This embodiment can give the transparent
heat-resistant resin, according to the present invention, which has
higher glass transition temperature, higher dealcoholation
conversion, and excellent heat resistance. In this case, the
dealcoholation reaction in the above reactor is run until the
conversion reaches preferably 60%, more preferably 70%, still more
preferably 80%, yet still more preferably 85%.
[0067] The reactor, usable for the aforementioned dealcoholation
reaction as preliminarily run prior to the dealcoholation reaction
in which the devolatilization step is carried out jointly and
simultaneously therewith, is not especially limited, but preferable
examples thereof include an autoclave, a vessel type reactor, and a
devolatilizer comprising a heat exchanger and a devolatilization
vessel. Furthermore, the extruder with vents, which is favorable
for the later dealcoholation reaction in which the devolatilization
step is carried out jointly and simultaneously therewith, is also
usable. The autoclave and the vessel type reactor are more
preferable. However, even when the reactor such as extruder with
vents is used, if the vent conditions are made mild, or if no
ventilation is made, or if factors such as temperature conditions,
barrel conditions, shape of screw, operational conditions of screw
are adjusted, then it might be possible to run the dealcoholation
reaction in the same state as a reaction state in the above vessel
type reactor, with the result that the transparent heat-resistant
resin according to the present invention could be obtained.
[0068] Preferable examples of processes for the aforementioned
dealcoholation reaction, as preliminarily run prior to the
dealcoholation reaction in which the devolatilization step is
carried out jointly and simultaneously therewith, include (i) a
process in which a catalyst is added to a polymerization solution
of the polymer, resultant from the polymerization reaction, to run
a reaction of the polymerization solution by heating; (ii) a
process in which a reaction of the polymerization solution is run
by heating without catalyst; and a process in which the above
process (i) or (ii) is carried out under pressure.
[0069] Incidentally, the "polymerization solution of the polymer"
which is introduced into the dealcoholation reaction means that
when the polymer as used is a product as obtained in the presence
of a solvent, the polymer may intactly be used for the
dealcoholation reaction, or the solvent may be once removed from
the polymer, and then a solvent which is fit for the dealcoholation
reaction may be added to the polymer again, and further that when
the polymer as used is a product as obtained without solvent, a
solvent which is fit for the dealcoholation reaction is added to
the polymer, and then the resultant mixture is used.
[0070] The solvent, usable for the aforementioned dealcoholation
reaction as preliminarily run prior to the dealcoholation reaction
in which the devolatilization step is carried out jointly and
simultaneously therewith, is not especially limited, but examples
thereof include: aromatic hydrocarbons such as toluene, xylene, and
ethylbenzene; ketones such as methyl ethyl ketone and methyl
isobutyl ketone; and chloroform, DMSO, and tetrahydrofuran. In
addition, considering that the use of a solvent having too high
boiling point would result in a high content of residual volatiles
in the resultant resin after devolatilization, solvents which
dissolve the polymer at treatment temperature and have a boiling
point of 50.about.200.degree. C. are preferable. More preferable
examples thereof include aromatic hydrocarbons such as toluene and
ketones such as methyl ethyl ketone.
[0071] As to the catalyst as added in the above process (i), the
esterification or transesterification catalyst which is
conventionally used such as p-toluensulfonic acid may be used, but,
in the present invention, the use of the aforementioned
organophosphorus compound is preferable. As to the timing to add
the catalyst, the catalyst may be added at the beginning and/or on
the way of the reaction. The amount of the catalyst as added is not
especially limited, but is preferably in the range of
0.001.about.10 weight %, more preferably 0.01.about.5 weight %,
still more preferably 0.01.about.2.5 weight %, yet still more
preferably 0.05.about.1 weight %, of the polymer. Neither the
heating temperature nor the heating period of time in the process
(i) is especially limited, but the heating temperature is
preferably not lower than room temperature, more preferably not
lower than 50.degree. C., and the heating period of time is
preferably in the range of 1.about.20 hours, more preferably
2.about.10 hours. In the case where the heating temperature is low
or where the heating period of time is short, there are
disadvantages in that the dealcoholation conversion is low. In
addition, in the case where the heating period of time is too long,
there are disadvantages in that the resin might become colored or
decompose.
[0072] Examples of the process (ii) include a process comprising
the step of heating the polymerization solution intactly with a
device such as an autoclave. The heating temperature is preferably
not lower than 100.degree. C., more preferably not lower than
150.degree. C., and further, the heating period of time is
preferably in the range of 1.about.20 hours, more preferably
2.about.10 hours. In the case where the heating temperature is low
or where the heating period of time is short, there are
disadvantages in that the dealcoholation conversion is low. In
addition, in the case where the heating period of time is too long,
there are disadvantages in that the resin might become colored or
decompose.
[0073] Incidentally, as to both processes (i) and (ii), there is no
problem even if they are carried out under pressure according to
conditions.
[0074] In addition, there is no problem even if part of the solvent
naturally volatilizes when the aforementioned dealcoholation
reaction is preliminarily run prior to the dealcoholation reaction
in which the devolatilization step is carried out jointly and
simultaneously therewith.
[0075] In addition, the dealcoholation conversion, as determined
from a weight loss between 150 and 300.degree. C. in dynamic TG
measurement, is preferably not lower than 60%, more preferably not
lower than 80%, still more preferably not lower than 85%, at the
end of the aforementioned dealcoholation reaction as preliminarily
run prior to the dealcoholation reaction in which the
devolatilization step is carried out jointly and simultaneously
therewith, in other words, just before the aforementioned
devolatilization step is initiated. In the case where this
conversion is lower than 60%, there are disadvantages in that even
if the dealcoholation reaction in which the devolatilization step
is carried out jointly and simultaneously therewith is run
subsequently, the dealcoholation conversion does not rise to a
sufficiently high level, and as a result, the transparent
heat-resistant resin according to the present invention cannot be
obtained.
[0076] Incidentally, when running the above dealcoholation
reaction, other thermoplastic resins may be caused to coexist with
the aforementioned polymer having a hydroxyl group and an ester
group in its molecular chain.
[0077] As to the aforementioned embodiment in which the
dealcoholation reaction of at least part of the hydroxyl group and
ester group in the molecular chain of the polymer resultant from
the polymerization reaction is preliminarily run to increase the
dealcoholation conversion in some degree, and thereafter the
dealcoholation reaction in which the devolatilization step is
carried out jointly and simultaneously therewith is run, a polymer
as obtained from the preliminary performed dealcoholation reaction
(polymer as obtained from the dealcoholation reaction of at least
part of the hydroxyl group and ester group in the molecular chain)
and the solvent may intactly be introduced into the dealcoholation
reaction in which the devolatilization step is carried out jointly
and simultaneously therewith, or the polymer and the solvent may be
introduced into this dealcoholation reaction after if necessary
carrying out other treatments, for example, in which the polymer is
isolated and then thereto the solvent is added again.
[0078] In addition, as to the production process according to the
present invention, the devolatilization step does not need to be
finished at the same time as the end of the dealcoholation
reaction, but may be finished at an interval after the end of the
dealcoholation reaction.
[0079] (Transparent Heat-resistant Resin):
[0080] The transparent heat-resistant resin, according to the
present invention, is obtained by a process including the step of
running a dealcoholation reaction of a polymer having a hydroxyl
group and an ester group in its molecular chain to introduce a
lactone ring structure into the polymer, and is characterized by
having a dealcoholation conversion of not lower than 90% as
determined from a weight loss between 150 and 300.degree. C. in
dynamic TG measurement, and is a resin which can easily be produced
by the above production process according to the present invention.
As is mentioned above, the transparent heat-resistant resin
according to the present invention has a very high dealcoholation
conversion of not lower than 90%, wherein the dealcoholation
conversion is preferably not lower than 95%, more preferably not
lower than 97%. Therefore, this resin is free from the conventional
demerit of foam or silver streak of the molded product resultant
from the molding step. Furthermore, this resin has sufficiently
high heat resistance due to the very high dealcoholation
conversion, and further has excellent transparency.
[0081] The transparent heat-resistant resin, according to the
present invention, has a yellowness index (YI) of not more than 6
in a 15 weight % chloroform solution, wherein the yellowness index
(YI) is preferably not more than 4, more preferably not more than
3, most preferably not more than 2. In the production process for
the transparent heat-resistant resin, according to the present
invention, if as is aforementioned the organophosphorus compound is
used as a catalyst for the dealcoholation reaction, then the
yellowness index (YI) of the resultant resin can be suppressed to
not more than 6. Transparent heat-resistant resins having a
yellowness index (YI) of more than 6 would be damaged in
transparency due to coloring and therefore could not be used for
inherent purposes.
[0082] The transparent heat-resistant resin, according to the
present invention, has a weight-average molecular weight of
preferably 40,000.about.300,000, more preferably
80,000.about.200,000, most preferably 100,000.about.200,000. If the
transparent heat-resistant resin according to the present invention
is produced using the organophosphorus compound as a catalyst for
the dealcoholation reaction, the molecular weight can effectively
be prevented from lowering in the devolatilization step, so that
the weight-average molecular weight of the resin can be retained in
the above range. In the case where the weight-average molecular
weight of the resin is lower than 40,000, there is a problem in
that a molded product from the resin has so low mechanical strength
as to tend to be brittle. On the other hand, in the case where the
weight-average molecular weight of the resin is higher than
300,000, there is a problem in that the resin has so low fluidity
as to be difficult to mold.
[0083] The transparent heat-resistant resin according to the
present invention comprises a polymer having a lactone ring
structure. The content of the lactone ring structure in this
polymer is preferably not lower than 5 weight %, more preferably
not lower than 10 weight %, still more preferably not lower than 15
weight %. The content of the lactone ring structure is determined
by the dealcoholation conversion. As is aforementioned, in the
present invention, the dealcoholation conversion of not lower than
90% can be realized, therefore a resin having a lactone ring
structure which satisfies the above range can easily be obtained.
In the case where the content of the lactone ring structure is
lower than 5 weight %, it tends to be impossible to give sufficient
heat resistance to the resultant transparent heat-resistant resin.
Incidentally, specifically, the content of the lactone ring
structure can be calculated by the method as described below in the
"DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS" portion
hereof.
[0084] The transparent heat-resistant resin according to the
present invention has a 5% weight loss temperature of preferably
not lower than 330.degree. C., more preferably not lower than
350.degree. C., most preferably not lower than 360.degree. C., in
the thermogravimetric analysis (TG). This 5% weight loss
temperature is an index of the heat resistance, and, in the case
where this is lower than 330.degree. C., sufficient thermal
stability cannot be exhibited. As is aforementioned, in the present
invention, the dealcoholation conversion of not lower than 90% can
be realized, therefore a resin which satisfies the above range can
easily be obtained.
[0085] The transparent heat-resistant resin according to the
present invention has a glass transition temperature (Tg) of
preferably not lower than 115.degree. C., more preferably not lower
than 120.degree. C., still more preferably not lower than
125.degree. C., most preferably not lower than 130.degree. C.
[0086] The content of residual volatiles in the transparent
heat-resistant resin according to the present invention is
preferably not higher than 1,500 ppm, more preferably not higher
than 1,000 ppm, in total. In the case where the content is higher
than these ranges, molding defects are caused, such as coloring
(due to factors such as deterioration in the molding step), foam,
or silver streak.
[0087] As to the transparent heat-resistant resin according to the
present invention, a molded product by injection molding thereof
has a total luminous transmittance of preferably not lower than
85%, more preferably not lower than 88%, most preferably not lower
than 90%, as measured by a method according to ASTM-D-1003. The
total luminous transmittance is an index of the transparency, and,
in the case where this is lower than 85%, the transparency is so
low that the resin cannot be used for inherent purposes.
[0088] As to the transparent heat-resistant resin according to the
present invention, a molded product by injection molding thereof
has a haze value of preferably not higher than 5%, more preferably
not higher than 3%, still more preferably not higher than 2%, as
measured by a method according to ASTM-D-1003. The haze value is an
index of the transparency, and, in the case where this is higher
than 5%, the transparency is so low that the resin cannot be used
for inherent purposes. Incidentally, also as to the below-mentioned
transparent heat-resistant resin composition, similarly, this haze
value is preferably not higher than 5%.
[0089] In addition, as to the transparent heat-resistant resin
according to the present invention, a molded product by injection
molding thereof has an impact strength (Izod value) of preferably
not lower than 49 N.multidot.cm/cm.sup.2 (5
kgf.multidot.cm/cm.sup.2), more preferably not lower than 98
N.multidot.cm/cm.sup.2 (10 kgf.multidot.cm/cm.sup.2), still more
preferably not lower than 147 N.multidot.cm/cm.sup.2 (15
kgf.multidot.cm/cm.sup.2), most preferably not lower than 167
N.multidot.cm/cm.sup.2 (17 kgf.multidot.cm/cm.sup.2), as measured
by a method according to ASTM-D-256 except that an unnotched test
piece is used.
[0090] Thus, the transparent heat-resistant resin according to the
present invention is a novel resin which has high heat resistance,
and further has good transparency with little coloring, and can
prevent foam or silver streak from occurring in the molded product,
and thus overcomes the demerits of conventional transparent
heat-resistant resins.
[0091] In addition, unless the performance or effect is damaged,
the resin may further comprise another polymer having no lactone
ring structure. However, even in such a case, the content of the
lactone ring structure in the transparent heat-resistant resin is
preferably not lower than 5 weight %, more preferably not lower
than 10 weight %, still more preferably not lower than 15 weight
%.
[0092] Accordingly, the transparent heat-resistant resin according
to the present invention is a novel resin which (a) has high heat
resistance, (b) further has excellent transparency, (c) can prevent
foam or silver streak from occurring in the molded product, and
thus overcomes the demerits of conventional transparent
heat-resistant resins.
[0093] The above transparent heat-resistant resins according to the
present invention have excellent properties as above, and therefore
may be mixed with additives, for example, antioxidants or
stabilizers, reinforcements (e.g. glass fibers), ultraviolet
absorbing agents, flame retardants, antistatic agents, colorants,
to prepare transparent heat-resistant resin molding materials, if
necessary. Furthermore, these transparent heat-resistant resin
molding materials may be molded to obtain molded products. These
transparent heat-resistant resin molding materials or molded
products have excellent properties because they comprise the
transparent heat-resistant resins according to the present
invention.
[0094] (Thermoplastic Resin Composition):
[0095] Vinyl chloride resins (poly(vinyl chloride)) and
acrylonitrile-styrene resins usually have glass transition
temperature (Tg) in the range of about 70 to about 100.degree. C.
and are therefore difficult to use in fields where the heat
resistance is demanded. As a result of diligent study to solve the
aforementioned problems, the present inventors found that either
the transparent heat-resistant resin, as obtained by the production
process according to the present invention, or the transparent
heat-resistant resin according to the present invention has
excellent miscibility with other thermoplastic resins, and further,
can enhance the heat resistance of those other thermoplastic resins
without damaging their properties such as transparency, mechanical
strength, and molding processibility.
[0096] That is to say, if either the transparent heat-resistant
resin, as obtained by the production process according to the
present invention, or the transparent heat-resistant resin
according to the present invention (hereinafter referred to as
polymer (A)) is mixed with a thermoplastic resin (B) other than the
polymer (A) as thermoplastic resins, then a thermoplastic resin
composition to solve the aforementioned problems is obtained. For
example, if a resin having the desired properties such as
transparency and mechanical strength is selected as the
thermoplastic resin (B) and mixed with the polymer (A), then the
heat resistance can be given to the thermoplastic resin (B) while
retaining its properties.
[0097] The thermoplastic resin (B) is not especially limited if it
is a thermoplastic resin other than the polymer (A), and such as
has the desired properties can fitly be selected. Examples of the
thermoplastic resin (B) include: olefin resins such as
polyethylene, polypropylene, ethylene-propylene copolymers, and
poly(4-methyl-pentene-1); halogen-containing polymers such as vinyl
chloride resins and chlorinated vinyl resins; acrylic polymers such
as poly(methyl methacrylate); styrenic polymers such as
polystyrene, styrene-methyl methacrylate copolymers,
acrylonitrile-styrene copolymers, and acrylonitrile-butadiene-
-styrene block copolymers; polyesters or polyarylates such as
poly(ethylene terephthalate) and poly(butylene terephthalate);
polyamides such as nylon 6, nylon 66, and nylon 610; polyacetals;
polycarbonates; polyphenylene oxide; polyphenylene sulfide;
polysulfones; polyether sulfones; polyether ether ketones;
polyoxybenzylene; polyamideimides. These may be used either alone
respectively or in combinations with each other.
[0098] When the transparency is given to the aimed thermoplastic
resin composition, the thermoplastic resin (B) can be used without
especial limitation if it is miscible with the polymer (A) and
transparent. In addition, if the thermoplastic resin (B) is a
thermoplastic resin having a refractive index that is the same as
of the polymer (A) or approximate thereto even if the thermoplastic
resin (B) has low miscibility, then such a thermoplastic resin has
little influence upon the transparency, and can be used similarly
favorably. From such a viewpoint, acrylic polymers (such as
poly(methyl methacrylate)), polystyrene, polycarbonates,
styrene-methyl methacrylate copolymers, vinyl chloride resins, and
acrylonitrile-styrene resins are particularly preferable among the
above-exemplified thermoplastic resins (B) in respect to excellent
transparency, and further, vinyl chloride resins and
acrylonitrile-styrene resins are particularly preferable among the
above-exemplified thermoplastic resins (B) in respect to excellent
miscibility.
[0099] In addition, rubber polymers may be used as the
aforementioned thermoplastic resin (B). Examples of the rubber
polymer include: polybutadiene-rubber-containing ABS resins,
acrylic-rubber-containing ASA resins,
polyolefinic-rubber-containing AES resins or HIPS; thermoplastic
elastomers such as polyolefins and polyesters, or elastomers such
as SBS and SIS. These rubber polymers may be used either alone
respectively or in combinations with each other, and of course, can
be used jointly with the previously exemplified thermoplastic
resins.
[0100] In addition, when the impact resistance is particularly
desired for the aimed thermoplastic resin composition, it is
preferable to use rubber-component-containing thermoplastic resins,
for example, ABS resins, ASA resins, AES resins, or vinyl chloride
resins that contain MBS resins, as the thermoplastic resin (B). If
these are used as the thermoplastic resin (B), a resin composition
having both excellent mechanical strength and high heat resistance
is obtained.
[0101] When the aforementioned resin having the transparency is
used as the thermoplastic resin (B), the miscibility of the polymer
(A) with the thermoplastic resin (B) is so excellent that the haze
value, as measured by a method in accordance with ASTM-D-1003 using
a molded test piece of the resultant thermoplastic resin
composition, retains a low value of not higher than 5%, and that
therefore high transparency can be exhibited. Specifically, for
example, when the vinyl chloride resin and/or the
acrylonitrile-styrene resin is used as the thermoplastic resin (B),
a molded test piece of the resultant thermoplastic resin
composition has a haze value of not higher than 5%. The haze value,
which is an index of the transparency, is more preferably not
higher than 4%, particularly preferably not higher than 2%.
[0102] The weight ratio of the polymer (A) to the thermoplastic
resin (B) in the composition is preferably in the range of polymer
(A)/thermoplastic resin (B)=1/99.about.99/1, more preferably
10/90.about.90/10. Particularly, when it is desired to enhance the
heat resistance as well as to make the thermoplastic resin (B)
exhibit its properties at the maximum, the weight ratio is
preferably in the range of polymer (A)/thermoplastic resin
(B)=10/90.about.80/20, more preferably 10/90.about.70/30,
particularly preferably 10/90.about.60/40.
[0103] The thermoplastic resin composition may be either a mixture
consisting of the polymer (A) and the thermoplastic resin (B), or
such a mixture which further contains various additives if
necessary. Specific examples of the various additives include
antioxidants or stabilizers, such as hindered phenols,
phosphorus-containing substances, and sulfur-containing substances;
reinforcements such as glass fibers and carbon fibers; ultraviolet
absorbing agents such as phenyl salicylate,
2-(2'-hydroxy-5methylphenyl)benzotriazole, and
2-hydroxybenzophenone; flame retardants such as tris(dibromopropyl)
phosphate, triphenyl phosphate, triallyl phosphate, ethylene
tetrabromide, antimony oxide, and zinc borate; antistatic agents
such as anionic surfactants, cationic surfactants, nonionic
surfactants, and amphoteric surfactants; colorants such as
inorganic pigments, organic pigments, and dyes; and fillers or
other resin reforming agents; but there is no especial limitation
thereto. The content of these additives is not especially limited
unless it damages the properties of the resultant thermoplastic
resin composition. However, specifically, the total content of the
polymer (A) and the thermoplastic resin (B) in the resultant
thermoplastic resin composition is preferably not lower than 1
weight %, more preferably not lower than 5 weight %, still more
preferably not lower than 10 weight %, most preferably not lower
than 20 weight %.
[0104] (Transparent Heat-resistant Resin Molding Material):
[0105] The transparent heat-resistant resin according to the
present invention may be mixed with additives to prepare a
transparent heat-resistant resin molding material, if necessary.
Examples of the additive include: antioxidants or stabilizers, such
as hindered phenols, phosphorus-containing substances, and
sulfur-containing substances; reinforcements such as glass fibers
and carbon fibers; ultraviolet absorbing agents such as phenyl
salicylate, 2-(2'-hydroxy-5-methylphenyl)- benzotriazole, and
2-hydroxybenzophenone; flame retardants such as tris(dibromopropyl)
phosphate, triphenyl phosphate, triallyl phosphate, ethylene
tetrabromide, antimony oxide, and zinc borate; antistatic agents
such as anionic surfactants, cationic surfactants, nonionic
surfactants, and amphoteric surfactants; and colorants such as
inorganic pigments, organic pigments, and dyes. The transparent
heat-resistant resin according to the present invention, as used
for this transparent heat-resistant resin molding material, is
preferably a transparent heat-resistant resin which is obtained by
a process including the step of running a dealcoholation reaction
of a polymer having a hydroxyl group and an ester group in its
molecular chain to introduce a lactone ring structure into the
polymer and is characterized by having a dealcoholation conversion
of not lower than 90% as determined from a weight loss between 150
and 300.degree. C. in dynamic TG measurement, or by having a
yellowness index (YI) of not more than 6 in a 15 weight %
chloroform solution. The molding material comprising the
transparent heat-resistant resin according to the present invention
is the transparent heat-resistant resin molding material according
to the present invention. The content of the transparent
heat-resistant resin according to the present invention in the
transparent heat-resistant resin molding material is preferably in
the range of 10.about.100 weight %, more preferably 30.about.100
weight %, most preferably 50.about.100 weight %.
[0106] (Molded Product):
[0107] The molded product according to the present invention is
obtained by molding the aforementioned transparent heat-resistant
resin molding material comprising the transparent heat-resistant
resin according to the present invention, and is a product as
molded in the range of preferably 150.about.350.degree. C., more
preferably in 200.about.300.degree. C., but the molding temperature
may be set fitly according to the properties of the resin such as
heat resistance, and is not especially limited. The molding method
is not especially limited, and examples thereof include injection
molding, blow molding, and extrusion molding.
[0108] The transparent heat-resistant resin according to the
present invention has excellent transparency, and therefore, for
example, can be applied to transparent optical lenses, optical
elements (e.g. light-leading materials available for lighting of
various gauges, displays or signboards; plastic optical fibers;
light-diffusible molded products of the shape, for example, of
films, sheets, bowls, or polyhedrons), and transparent parts for
purposes such as OA instruments or cars (e.g. lenses for lazer beam
printers; lamp lenses for head lamps or fog lamps of cars or for
signal lamps), and further, is favorable in respect to easy
moldability into various shapes. Moreover, the resin or composition
thereof according to the present invention is, for example, further
applicable to: molded products of the shape of film or sheet;
laminate sheets with other resins; surface layer resins for
bathtubs.
[0109] Because the molded product according to the present
invention is obtained from the transparent heat-resistant resin
molding material comprising the transparent heat-resistant resin
according to the present invention, this molded product is very
useful in respect to being able to entirely or almost entirely
avoid foam or silver streak which are unavoidable in cases of
conventional transparent heat-resistant resin molded products.
[0110] Incidentally, the aforementioned thermoplastic resin
composition is also favorably usable as a molding material for the
aforementioned molded product.
[0111] (Effects and Advantages of the Invention):
[0112] The present invention can provide a production process for a
transparent heat-resistant resin, and further, a transparent
heat-resistant resin and uses therefor, wherein the production
process involves high dealcoholation conversion and a low content
of residual volatiles in the resultant resin, and therefore can
prevent foam or silver streak from occurring in the molded product,
and further, facilitates melt-molding such as injection molding,
and is fit for industrial production, and involves good
efficiency.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0113] Hereinafter, the present invention is more specifically
illustrated by the following examples of some preferred embodiments
in comparison with comparative examples not according to the
invention. However, the invention is not limited to these examples.
Incidentally, hereinafter, the unit "part(s)" is by weight.
[0114] (Analyses of Polymerization Conversion and Composition of
Polymer):
[0115] The conversion in the polymerization reaction and the
content of a specific monomer unit in the polymer were determined
by measuring the amount of unreacted monomer in the resultant
polymerization reaction mixture by gas chromatography (device name:
GC-14A, made by Shimadzu Corporation).
[0116] (Dealcoholation Conversion and Lactone Ring Structure
Content):
[0117] The polymer (or polymer solution or pellets) resultant from
the dealcoholation reaction was once dissolved into tetrahydrofuran
or diluted therewith, and then added into an excess of hexane or
methanol to carry out reprecipitation. The separated precipitate
was dried under vacuum (at 1 mmHg (1.33 hPa), 80.degree. C. for not
shorter than 3 hours) to remove fractions such as volatiles. Then,
the dealcoholation conversion of the resultant white solid resin
was analyzed by the following method (dynamic TG method).
[0118] Measurement device: Thermo Plus2 TG-8120 Dynamic TG (made by
Rigaku Co., Ltd.)
[0119] Measurement conditions:
[0120] amount of sample=about 5 mg
[0121] temperature elevation rate=10.degree. C./min
[0122] atmosphere=nitrogen flow of 200 ml/min
[0123] method=stepwise isothermal analysis (SIA method) (controlled
at weight loss rate of not higher than 0.005%/sec between 60 and
500.degree. C.)
[0124] Conversion: as determined from a weight loss on the
dealcoholation reaction in the elevating temperature range of from
150.degree. C. before the beginning of the weight loss to
300.degree. C. before the beginning of the decomposition of the
polymer in this measurement on the basis of a weight loss to occur
when all hydroxyl groups in the composition of the polymer
resultant from Referential Examples 1 to 3 below are dealcoholated
in the form of methanol.
[0125] That is to say, in the thermal analysis (dynamic TG) of the
polymer having a lactone ring structure, the weight loss of from
150 to 300.degree. C. was measured to regard the resultant found
weight loss as (X). On the other hand, the theoretical weight loss
is calculated as (Y) from the composition of the polymer on the
assumption that all hydroxyl groups in the composition of the
polymer are dealcoholated by being converted into an alcohol to
join the formation of the lactone ring (in other words, the
theoretical weight loss is a weight loss as calculated on the
assumption that the dealcoholation reaction occurred in the ratio
of 100% in the composition). Incidentally, more specifically, the
theoretical weight loss (Y) can be calculated from the molar ratio
of a raw monomer, having a structure (hydroxyl group) to join the
dealcoholation reaction, in the polymer, and from the content of
this raw monomer in the composition of the polymer. If these values
(X, Y) are substituted for the following dealcoholation calculation
formula:
[0126] 1-(found weight loss (X)/theoretical weight loss (Y))
[0127] and if the resultant value is represented with %, then the
dealcoholation conversion is obtained. Furthermore, the content of
the lactone ring structure in the polymer can be calculated by
considering the expected lactonization to have been made
corresponding to the resultant dealcoholation conversion, and by
multiplying the content (weight ratio) of the raw monomer, having a
structure (hydroxyl group) to join the lactonization, in the
composition of the polymer by the above dealcoholation
conversion.
[0128] For example, the content of the lactone ring structure in
the polymer resultant from Example 1 below is calculated as
follows. If the theoretical weight loss (Y) of this polymer is
determined from molecular weight of methanol=32, molecular weight
of methyl 2-(hydroxymethyl)acryla- te=116, and content (weight
ratio) of methyl 2-(hydroxymethyl)acrylate in polymer=20.0% in
composition, then (32/116).times.20.0.apprxeq.5.52 weight % is
given. On the other hand, the weight loss (X) as found by the
dynamic TG measurement was 0.23 weight %. If these values are
substituted for the above dealcoholation calculation formula, then
1-(0.23/5.52).apprxeq.0.958 is given, so the dealcoholation
conversion is 95.8%. Furthermore, if the expected lactonization is
considered to have been made corresponding to the resultant
dealcoholation conversion in the polymer, and if the content of
methyl 2-(hydroxymethyl)acrylate in the polymer (20.0%) is
multiplied by the above dealcoholation conversion (95.8%=0.958),
then the content of the lactone ring structure in the polymer is
given as 19.2 (=20.0.times.0.958) weight %.
[0129] Incidentally, the dealcoholation conversion as above is an
important index to regulate the reaction state of the polymer when
the dealcoholation reaction is preliminarily run prior to the
dealcoholation reaction in which the devolatilization step is
carried out jointly and simultaneously therewith.
[0130] (Weight-average Molecular Weight):
[0131] The weight-average molecular weight of the polymer was
determined in terms of polystyrene by GPC (GPC system, made by
TOSOH Corporation).
[0132] (Yellowness Index YI of Resin):
[0133] The yellowness index YI of the resin was measured by
dissolving the resin into chloroform to prepare a 15 weight %
solution, and then placing this solution into a quartz cell to
analyze the solution with transmitted light using a color
difference meter (device name: SZ-.SIGMA.90, made by Nippon
Denshoku Kogyo Co., Ltd.) in accordance with JIS-K-7103.
[0134] (Thermal Analysis of Resin):
[0135] The thermal analysis of the resin was carried out by TG
(device name: TG-8110, made by Rigaku Co., Ltd.) and DSC (device
name: DSC-8230, made by Rigaku Co., Ltd.) under the following
conditions: amount of sample=about 10 mg, temperature elevation
rate=10.degree. C./min, nitrogen flow=50 cc/min. Incidentally, the
glass transition temperature (Tg) was determined from the midpoint
temperature in accordance with ASTM-D-3418.
[0136] (Measurement of Volatile Content in Resin):
[0137] The residual volatile content in the resin was measured by
gas chromatography (device name: GC-14A, made by Shimadzu
Corporation).
[0138] (Transparency of Molded Product):
[0139] The resultant resin or thermoplastic resin composition was
subjected to injection molding (thickness=3.2 mm) to measure the
total luminous transmittance and the haze value of the resultant
molded product as an index of the transparency with a hazemeter
(device name: NDH-1001DP, made by Nippon Denshoku Kogyo Co., Ltd.)
in accordance with ASTM-D-1003.
[0140] (Confirmation of Lactone Ring in Resin):
[0141] Whether a lactone ring was present in the framework of the
resin or not was confirmed by infrared absorption spectroscopy and
.sup.13C--NMR. Incidentally, the measurement by the infrared
absorption spectroscopy was carried out with an FTS-45 infrared
spectrophotometer (made by BIO-RAD), and the measurement by the
.sup.13C--NMR was carried out with FT-NMR UNITY plus400 (made by
Varian).
[0142] (Heat Resistance):
[0143] The heat resistance of the resultant thermoplastic resin
composition was evaluated with the glass transition temperature
(Tg) as determined by the DSC measurement in the aforementioned
thermal analysis of the resin. That is to say, the higher the glass
transition temperature is, the more excellent the heat resistance
is.
[0144] (Miscibility):
[0145] The glass transition temperature (Tg) of the resultant
thermoplastic resin composition was measured by the aforementioned
DSC measurement. A case where the glass transition temperature was
observed at only one point was evaluated as ".largecircle.", and a
case where the glass transition temperature was observed at more
than one point was evaluated as "X".
[0146] (Transparency of Thermoplastic Resin Composition):
[0147] A tetrahydrofuran solution of the resultant thermoplastic
resin composition was coated into a uniform thickness onto a glass
plate and then dried to prepare a cast film. The transparency of
this cast film was observed with the eye and evaluated as follows:
nonturbid and colorless transparent: ".largecircle.", white turbid:
"X".
[0148] (Impact Resistance of Molded Product):
[0149] The impact strength (Izod value) was measured as an index of
the impact resistance using an Izod impact tester (made by Toyo
Seiki Co., Ltd.) in accordance with ASTM-D-256 except that an
unnotched test piece, as obtained by injection molding of the
resultant resin, was used.
REFERENTIAL EXAMPLE 1
[0150] Five parts of methyl 2-(hydroxymethyl)acrylate, 20 parts of
methyl methacrylate, and 25 parts of toluene were placed into a
reaction vessel of 30 liters as equipped with a stirrer, a
temperature sensor, a condenser, a nitrogen-introducing tube, and a
dropping pump. The temperature was elevated to 100.degree. C. under
a nitrogen stream. Then, 0.075 parts of t-butyl peroxyisopropyl
carbonate (initiator) was added, and simultaneously therewith, a
solution comprising 5 parts of methyl 2-(hydroxymethyl)acrylate, 20
parts of methyl methacrylate, 25 parts of toluene, and 0.075 parts
of the initiator was dropwise added over a period of 3.5 hours,
while solution polymerization was carried out in the range of
100.about.110.degree. C. Thereafter, aging was carried out for 1.5
hours. The polymerization conversion was 91.8%, and the content
(weight ratio) of methyl 2-(hydroxymethyl)acrylate in the resultant
polymer was 20.0%. In addition, the weight-average molecular weight
of this polymer was 130,000.
EXAMPLE 1
[0151] The polymer solution, resultant from Referential Example 1,
was introduced at a treatment rate of 0.7 kg/hour in terms of
amount of resin into a vent type twin-screw extruder (.PHI.=29.75
mm, L/D=30) of: barrel temperature=250.degree. C., revolution
number=100 rpm, vacuum=10.about.300 mmHg (13.3.about.400 hPa),
number of rear vents=1, and number of fore vents=4. A
dealcoholation reaction and a devolatilization were carried out in
the extruder, and the resultant product was extruded to obtain
transparent pellets, of which the yellowness index YI was 2.1.
[0152] The dealcoholation conversion of the resultant pellets was
determined by the foregoing method, with the result that the
dealcoholation conversion was 95.8% (a weight loss of 0.23% was
detected in the measurement by the dynamic TG method, and the
content of the lactone ring structure as determined by this method
was 19.2 weight %). In addition, it was confirmed by the infrared
absorption spectroscopy and the .sup.13C--NMR that lactone rings
were formed in the framework of the resultant resin.
[0153] In addition, the weight-average molecular weight of the
above pellets was 80,000.
[0154] In addition, the 5% weight loss temperature, which was an
index of the heat resistance, of the above pellets was 366.degree.
C. Therefrom, it was found that the above pellets had excellent
thermal stability in the high temperature region. Incidentally, the
glass transition temperature was 126.degree. C.
[0155] In addition, the residual volatile contents in the pellets
were as follows:
[0156] Methyl methacrylate: 470 ppm
[0157] Methyl 2-(hydroxymethyl)acrylate: 50 ppm
[0158] Methanol: 280 ppm
[0159] Toluene: 90 ppm
[0160] The above pellets were subjected to injection molding at
250.degree. C. to obtain a colorless transparent molded product
(total luminous transmittance: 90.1%, haze value: 2.5%) in which
neither foam nor silver streak was seen. In addition, the impact
strength (Izod value) was measured to obtain a value of 68.6
N.multidot.cm/cm.sup.2 (7 kgf.multidot.cm/cm2).
[0161] These results are collected in Table 1.
EXAMPLE 2
[0162] Methyl isobutyl ketone and phenylphosphonic acid were added
to the polymer solution resultant from Referential Example 1,
wherein the amount of the methyl isobutyl ketone as added was 37.5
parts per 100 parts of the polymer solution, and the amount of the
phenylphosphonic acid as added was 0.01 part per 1 part of polymer
component. A dealcoholation reaction was carried out at 100.degree.
C. for 5 hours under a nitrogen stream.
[0163] A portion of the resultant reaction solution was sampled to
determine the dealcoholation conversion by the foregoing method,
with the result that the dealcoholation conversion was 88.0% (a
weight loss of 0.66% was detected in the measurement by the dynamic
TG method).
[0164] The polymer solution, resultant from the above
dealcoholation reaction, was introduced at a treatment rate of 2.0
kg/hour in terms of amount of resin into a vent type twin-screw
extruder (.PHI.=29.75 mm, L/D=30) of: barrel
temperature=250.degree. C., revolution number=100 rpm,
vacuum=10.about.300 mmHg (13.3.about.400 hPa), number of rear
vents=1, and number of fore vents=4. A devolatilization treatment
was carried out in the extruder while completing the dealcoholation
reaction, and the resultant product was extruded to obtain
transparent pellets, of which the yellowness index YI was 5.3.
[0165] The dealcoholation conversion of the resultant pellets was
determined by the foregoing method, with the result that the
dealcoholation conversion was 98.4% (a weight loss of 0.09% was
detected in the measurement by the dynamic TG method, and the
content of the lactone ring structure as determined by this method
was 19.7 weight %).
[0166] In addition, the weight-average molecular weight of the
above pellets was 120,000, and further, the 5% weight loss
temperature, which was an index of the heat resistance, of the
above pellets was 366.degree. C. Therefrom, it was found that the
above pellets had excellent thermal stability in the high
temperature region. Incidentally, the glass transition temperature
was 134.degree. C.
[0167] In addition, the residual volatile contents in the pellets
were as follows:
[0168] Methyl methacrylate: 60 ppm
[0169] Methyl 2-(hydroxymethyl)acrylate: 80 ppm
[0170] Methanol: 270 ppm
[0171] Toluene: 170 ppm
[0172] Methyl isobutyl ketone: 240 ppm
[0173] The above pellets were subjected to injection molding at
250.degree. C. to stably (continuously) obtain a colorless
transparent molded product (total luminous transmittance: 89.8%,
haze value: 2.8%) in which neither foam nor silver streak was seen.
No foam was seen in the molded product, and further, even if the
resin was allowed to reside in an injection molding machine at
250.degree. C. for 5 minutes and then subjected to injection
molding, no foam was seen in the resultant molded product. In
addition, the impact strength (Izod value) was measured to obtain a
value of 157 N.multidot.cm/cm.sup.2 (16 kgf.multidot.cm/cm.sup.2-
).
[0174] These results are collected in Table 1.
EXAMPLE 3
[0175] The polymer solution, resultant from Referential Example 1,
was placed into an autoclave, and the temperature of the solution
was then elevated to 200.degree. C., at which the solution was
heated under pressure for 10 hours to carry out a dealcoholation
reaction.
[0176] A portion of the resultant reaction solution was sampled to
determine the dealcoholation conversion by the foregoing method,
with the result that the dealcoholation conversion was 87.7% (a
weight loss of 0.68% was detected in the measurement by the dynamic
TG method).
[0177] The polymer solution, resultant from the above
dealcoholation reaction, was introduced at a treatment rate of 2.0
kg/hour in terms of amount of resin into a vent type twin-screw
extruder (.PHI.=29.75 mm, L/D=30) of: barrel
temperature=250.degree. C., revolution number=100 rpm,
vacuum=10.about.300 mmHg (13.3.about.400 hPa), number of rear
vents=1, and number of fore vents=4. A devolatilization treatment
was carried out in the extruder while completing the dealcoholation
reaction, and the resultant product was extruded to obtain
transparent pellets, of which the yellowness index YI was 2.2.
[0178] The dealcoholation conversion of the resultant pellets was
determined by the foregoing method, with the result that the
dealcoholation conversion was 98.0% (a weight loss of 0.11% was
detected in the measurement by the dynamic TG method, and the
content of the lactone ring structure as determined by this method
was 19.6 weight %).
[0179] In addition, the weight-average molecular weight of the
above pellets was 99,000, and further, the 5% weight loss
temperature, which was an index of the heat resistance, of the
above pellets was 368.degree. C. Therefrom, it was found that the
above pellets had excellent thermal stability in the high
temperature region. Incidentally, the glass transition temperature
was 130.degree. C.
[0180] In addition, the residual volatile contents in the pellets
were as follows:
[0181] Methyl methacrylate: 90 ppm
[0182] Methyl 2-(hydroxymethyl)acrylate: 80 ppm
[0183] Methanol: 270 ppm
[0184] Toluene: 180 ppm
[0185] The above pellets were subjected to injection molding at
250.degree. C. to stably (continuously) obtain a colorless
transparent molded product (total luminous transmittance: 90.1%,
haze value: 2.3%) in which neither foam nor silver streak was seen.
No foam was seen in the molded product, and further, even if the
resin was allowed to reside in an injection molding machine at
250.degree. C. for 5 minutes and then subjected to injection
molding, no foam was seen in the resultant molded product. In
addition, the impact strength (Izod value) was measured to obtain a
value of 147 N.multidot.cm/cm.sup.2 (15 kgf.multidot.cm/cm.sup.2-
).
[0186] These results are collected in Table 1.
EXAMPLE 4
[0187] The polymer solution, resultant from Referential Example 1,
was caused to pass through a heat exchanger (instead of the
twin-screw extruder of Example 1) to elevate the temperature of the
solution to 250.degree. C., and then intactly introduced into a
devolatilization vessel with a vacuum of 150 mmHg (200 hPa) to
carry out a dealcoholation reaction and a devolatilization
simultaneously with each other, and the resultant product was
extracted with a gear pump at a treatment rate of 1 kg/hour in
terms of amount of resin, with the result that a transparent resin
was obtained. The yellowness index YI of this resin was 2.1.
[0188] The dealcoholation conversion of the resultant resin was
determined by the foregoing method, with the result that the
dealcoholation conversion was 95.3% (a weight loss of 0.26% was
detected in the measurement by the dynamic TG method, and the
content of the lactone ring structure as determined by this method
was 19.1 weight %).
[0189] In addition, the weight-average molecular weight of the
above resin was 90,000.
[0190] In addition, the 5% weight loss temperature, which was an
index of the heat resistance, of the above resin was 363.degree. C.
Therefrom, it was found that the above resin had excellent thermal
stability in the high temperature region. Incidentally, the glass
transition temperature was 126.degree. C.
[0191] In addition, the residual volatile contents in the resin
were as follows:
[0192] Methyl methacrylate: 520 ppm
[0193] Methyl 2-(hydroxymethyl)acrylate: 100 ppm
[0194] Methanol: 380 ppm
[0195] Toluene: 330 ppm
[0196] The above resin was subjected to injection molding at
250.degree. C. to obtain a colorless transparent molded product
(total luminous transmittance: 90.1%, haze value: 2.7%) in which
neither foam nor silver streak was seen. In addition, the impact
strength (Izod value) was measured to obtain a value of 88.3
N.multidot.cm/cm.sup.2 (9 kgf.multidot.cm/cm.sup.2).
[0197] These results are collected in Table 1.
EXAMPLE 5
[0198] Methyl isobutyl ketone and phenylphosphonic acid were added
to the polymer solution resultant from Referential Example 1,
wherein the amount of the methyl isobutyl ketone as added was 37.5
parts per 100 parts of the polymer solution, and the amount of the
phenylphosphonic acid as added was 0.01 part per 1 part of polymer
component. The resultant mixture was introduced at a treatment rate
of 2.0 kg/hour in terms of amount of resin into a vent type
twin-screw extruder (.PHI.=29.75 mm, L/D =30) of: barrel
temperature=250.degree. C., revolution number=100 rpm,
vacuum=10.about.300 mmHg (13.3.about.400 hPa), number of rear
vents=1, and number of fore vents=4. A dealcoholation reaction and
a devolatilization treatment were carried out in the extruder, and
the resultant product was extruded to obtain transparent pellets,
of which the yellowness index YI was 5.3.
[0199] The dealcoholation conversion of the resultant pellets was
determined by the foregoing method, with the result that the
dealcoholation conversion was 96.7% (a weight loss of 0.18% was
detected in the measurement by the dynamic TG method, and the
content of the lactone ring structure as determined by this method
was 19.3 weight %).
[0200] In addition, the weight-average molecular weight of the
above pellets was 110,000, and further, the 5% weight loss
temperature, which was an index of the heat resistance, of the
above pellets was 366.degree. C. Therefrom, it was found that the
above pellets had excellent thermal stability in the high
temperature region. Incidentally, the glass transition temperature
was 133.degree. C.
[0201] In addition, the residual volatile contents in the pellets
were as follows:
[0202] Methyl methacrylate: 80 ppm
[0203] Methyl 2-(hydroxymethyl)acrylate: 110 ppm
[0204] Methanol: 290 ppm
[0205] Toluene: 170 ppm
[0206] Methyl isobutyl ketone: 240 ppm
[0207] The above pellets were subjected to injection molding at
250.degree. C. to stably (continuously) obtain a colorless
transparent molded product (total luminous transmittance: 89.8%,
haze value: 2.8%) in which neither foam nor silver streak was seen.
In addition, the impact strength (Izod value) was measured to
obtain a value of 137 N.multidot.cm/cm.sup.2 (14
kgf.multidot.cm/cm.sup.2).
[0208] These results are collected in Table 1.
EXAMPLE 6
[0209] Methyl isobutyl ketone and phenylphosphonous acid were added
to the polymer solution resultant from Referential Example 1,
wherein the amount of the methyl isobutyl ketone as added was 37.5
parts per 100 parts of the polymer solution, and the amount of the
phenylphosphonous acid as added was 0.005 parts per 1 part of
polymer component. A dealcoholation reaction was carried out at
100.degree. C. for 5 hours under a nitrogen stream.
[0210] A portion of the resultant reaction solution was sampled to
determine the dealcoholation conversion by the foregoing method,
with the result that the dealcoholation conversion was 88.0% (a
weight loss of 0.66% was detected in the measurement by the dynamic
TG method) at this point of time.
[0211] Next, a devolatilization treatment of the polymer solution,
resultant from the above dealcoholation reaction, was carried out
in the same way as of Example 2 while completing the dealcoholation
reaction, and the resultant product was extruded to obtain
transparent pellets.
[0212] The dealcoholation conversion of the resultant pellets was
determined by the foregoing method, with the result that the
dealcoholation conversion was 98.4% (a weight loss of 0.09% was
detected in the measurement by the dynamic TG method, and the
content of the lactone ring structure as determined by this method
was 19.7 weight %). In addition, the yellowness index YI of the
above pellets was 1.7.
[0213] In addition, the weight-average molecular weight of the
above pellets was 120,000, and further, the 5% weight loss
temperature, which was an index of the heat resistance, of the
above pellets was 367.degree. C. Therefrom, it was found that the
above pellets had excellent thermal stability in the high
temperature region. Incidentally, the glass transition temperature
was 135.degree. C.
[0214] In addition, the residual volatile contents in the pellets
were as follows:
[0215] Methyl methacrylate: 60 ppm
[0216] Methyl 2-(hydroxymethyl)acrylate: 70 ppm
[0217] Methanol: 190 ppm
[0218] Toluene: 160 ppm
[0219] Methyl isobutyl ketone: 230 ppm
[0220] The above pellets were subjected to injection molding at
250.degree. C. to stably (continuously) obtain a colorless
transparent molded product (total luminous transmittance: 91.0%,
haze value: 2.5%) in which neither foam nor silver streak was seen.
No foam was seen in the molded product, and further, even if the
resin was allowed to reside in an injection molding machine at
250.degree. C. for 5 minutes and then subjected to injection
molding, no foam was seen in the resultant molded product. In
addition, the impact strength (Izod value) was measured to obtain a
value of 177 N.multidot.cm/cm.sup.2 (18 kgf.multidot.cm/cm.sup.2-
).
[0221] These results are collected in Table 2.
EXAMPLE 7
[0222] Methyl isobutyl ketone and dimethyl phosphite were added to
the polymer solution resultant from Referential Example 1, wherein
the amount of the methyl isobutyl ketone as added was 37.5 parts
per 100 parts of the polymer solution, and the amount of the
dimethyl phosphite as added was 0.015 parts per 1 part of polymer
component. A dealcoholation reaction was carried out at 100.degree.
C. for 5 hours under a nitrogen stream.
[0223] A portion of the resultant reaction solution was sampled to
determine the dealcoholation conversion by the foregoing method,
with the result that the dealcoholation conversion was 86.8% (a
weight loss of 0.73% was detected in the measurement by the dynamic
TG method) at this point of time.
[0224] Next, a devolatilization treatment of the polymer solution,
resultant from the above dealcoholation reaction, was carried out
in the same way as of Example 2 while completing the dealcoholation
reaction, and the resultant product was extruded to obtain
transparent pellets.
[0225] The dealcoholation conversion of the resultant pellets was
determined by the foregoing method, with the result that the
dealcoholation conversion was 97.1% (a weight loss of 0.16% was
detected in the measurement by the dynamic TG method, and the
content of the lactone ring structure as determined by this method
was 19.4 weight %). In addition, the yellowness index YI of the
above pellets was 1.5.
[0226] In addition, the weight-average molecular weight of the
above pellets was 117,000, and further, the 5% weight loss
temperature, which was an index of the heat resistance, of the
above pellets was 365.degree. C. Therefrom, it was found that the
above pellets had excellent thermal stability in the high
temperature region. Incidentally, the glass transition temperature
was 135.degree. C.
[0227] In addition, the residual volatile contents in the pellets
were as follows:
[0228] Methyl methacrylate: 80 ppm
[0229] Methyl 2-(hydroxymethyl)acrylate: 90 ppm
[0230] Methanol: 290 ppm
[0231] Toluene: 170 ppm
[0232] Methyl isobutyl ketone: 240 ppm
[0233] The above pellets were subjected to injection molding at
250.degree. C. to stably (continuously) obtain a colorless
transparent molded product (total luminous transmittance: 90.9%,
haze value: 1.5%) in which neither foam nor silver streak was seen.
No foam was seen in the molded product, and further, even if the
resin was allowed to reside in an injection molding machine at
250.degree. C. for 5 minutes and then subjected to injection
molding, no foam was seen in the resultant molded product. In
addition, the impact strength (Izod value) was measured to obtain a
value of 167 N.multidot.cm/cm.sup.2 (17 kgf.multidot.cm/cm.sup.2-
).
[0234] These results are collected in Table 2.
EXAMPLE 8
[0235] Methyl isobutyl ketone and a methyl phosphate/dimethyl
phosphate mixture (made by Tokyo Kasei Kogyo Co., Ltd.) were added
to the polymer solution resultant from Referential Example 1,
wherein the amount of the methyl isobutyl ketone as added was 37.5
parts per 100 parts of the polymer solution, and the amount of the
methyl phosphate/dimethyl phosphate mixture as added was 0.001 part
per 1 part of polymer component. A dealcoholation reaction was
carried out at 100.degree. C. for 5 hours under a nitrogen
stream.
[0236] A portion of the resultant reaction solution was sampled to
determine the dealcoholation conversion by the foregoing method,
with the result that the dealcoholation conversion was 88.8% (a
weight loss of 0.62% was detected in the measurement by the dynamic
TG method) at this point of time.
[0237] Next, a devolatilization treatment of the polymer solution,
resultant from the above dealcoholation reaction, was carried out
in the same way as of Example 2 while completing the dealcoholation
reaction, and the resultant product was extruded to obtain
transparent pellets.
[0238] The dealcoholation conversion of the resultant pellets was
determined by the foregoing method, with the result that the
dealcoholation conversion was 98.2% (a weight loss of 0.10% was
detected in the measurement by the dynamic TG method, and the
content of the lactone ring structure as determined by this method
was 19.6 weight %). In addition, the yellowness index YI of the
above pellets was 0.8.
[0239] In addition, the weight-average molecular weight of the
above pellets was 120,000, and further, the 5% weight loss
temperature, which was an index of the heat resistance, of the
above pellets was 366.degree. C. Therefrom, it was found that the
above pellets had excellent thermal stability in the high
temperature region. Incidentally, the glass transition temperature
was 134.degree. C.
[0240] In addition, the residual volatile contents in the pellets
were as follows:
[0241] Methyl methacrylate: 50 ppm
[0242] Methyl 2-(hydroxymethyl)acrylate: 60 ppm
[0243] Methanol: 240 ppm
[0244] Toluene: 170 ppm
[0245] Methyl isobutyl ketone: 250 ppm
[0246] The above pellets were subjected to injection molding at
250.degree. C. to stably (continuously) obtain a colorless
transparent molded product (total luminous transmittance: 92.5%,
haze value: 0.7%) in which neither foam nor silver streak was seen.
No foam was seen in the molded product, and further, even if the
resin was allowed to reside in an injection molding machine at
250.degree. C. for 5 minutes and then subjected to injection
molding, no foam was seen in the resultant molded product. In
addition, the impact strength (Izod value) was measured to obtain a
value of 177 N.multidot.cm/cm.sup.2 (18 kgf.multidot.cm/cm.sup.2-
).
[0247] These results are collected in Table 2.
EXAMPLE 9
[0248] Methyl isobutyl ketone and p-toluenesulfonic acid
monohydrate were added to the polymer solution resultant from
Referential Example 1, wherein the amount of the methyl isobutyl
ketone as added was 37.5 parts per 100 parts of the polymer
solution, and the amount of the p-toluensulfonic acid monohydrate
as added was 0.005 parts per 1 part of polymer component. A
dealcoholation reaction was carried out at 100.degree. C. for 5
hours under a nitrogen stream.
[0249] A portion of the resultant reaction solution was sampled to
determine the dealcoholation conversion by the foregoing method,
with the result that the dealcoholation conversion was 88.8% (a
weight loss of 0.62% was detected in the measurement by the dynamic
TG method) at this point of time.
[0250] Next, a devolatilization treatment of the polymer solution,
resultant from the above dealcoholation reaction, was carried out
in the same way as of Example 2 while completing the dealcoholation
reaction, and the resultant product was extruded to obtain
transparent pellets.
[0251] The dealcoholation conversion of the resultant pellets was
determined by the foregoing method, with the result that the
dealcoholation conversion was 98.4% (a weight loss of 0.09% was
detected in the measurement by the dynamic TG method, and the
content of the lactone ring structure as determined by this method
was 19.7 weight %). In addition, the yellowness index YI of the
above pellets was 11.8.
[0252] In addition, the weight-average molecular weight of the
above pellets was 120,000, and further, the 5% weight loss
temperature, which was an index of the heat resistance, of the
above pellets was 365.degree. C. Therefrom, it was found that the
above pellets had excellent thermal stability in the high
temperature region. Incidentally, the glass transition temperature
was 135.degree. C.
[0253] In addition, the residual volatile contents in the pellets
were as follows:
[0254] Methyl methacrylate: 60 ppm
[0255] Methyl 2-(hydroxymethyl)acrylate: 70 ppm
[0256] Methanol: 280 ppm
[0257] Toluene: 160 ppm
[0258] Methyl isobutyl ketone: 230 ppm
[0259] The above pellets were subjected to injection molding at
250.degree. C. to stably (continuously) obtain a colored
transparent molded product (total luminous transmittance: 86.5%,
haze value: 5.5%) in which neither foam nor silver streak was seen.
No foam was seen in the molded product, and further, even if the
resin was allowed to reside in an injection molding machine at
250.degree. C. for 5 minutes and then subjected to injection
molding, no foam was seen in the resultant molded product. In
addition, the impact strength (Izod value) was measured to obtain a
value of 167 N.multidot.cm/cm.sup.2 (17 kgf.multidot.cm/cm.sup.2-
).
[0260] These results are collected in Table 2.
COMPARATIVE EXAMPLE 1
[0261] The polymer solution, resultant from Referential Example 1,
was diluted with tetrahydrofuran and then added into an excess of
hexane to carry out reprecipitation. The separated precipitate was
dried under vacuum (at 1 mmHg (1.33 hPa), 80.degree. C. for 3
hours), and 10 parts of the resultant white solid resin was
dissolved into 60 parts of DMSO and then heated at 150.degree. C.
for 1 hour. After being cooled, the reaction solution was diluted
with tetrahydrofuran and then added into an excess of methanol to
carry out reprecipitation. The separated precipitate was dried
under vacuum (at 1 mmHg (1.33 hPa), 80.degree. C. for 3 hours) to
obtain a white solid resin.
[0262] The dealcoholation conversion of the resultant resin was
determined by the foregoing method, with the result that the
dealcoholation conversion was 44.2% (a weight loss of 3.08% was
detected in the measurement by the dynamic TG method, and the
content of the lactone ring structure as determined by this method
was 8.8 weight The above resin was subjected to injection molding
at 220.degree. C. or 250.degree. C., with the result that
considerably much foam and silver streak were, however, seen in the
molded product.
[0263] These results are collected in Table 3.
COMPARATIVE EXAMPLE 2
[0264] The polymer solution, resultant from Referential Example 1,
was diluted with tetrahydrofuran and then added into an excess of
hexane to carry out reprecipitation. The separated precipitate was
dried under vacuum (at 1 mmHg (1.33 hPa), 80.degree. C. for 3
hours), and 10 parts of the resultant white solid resin was
dissolved into 60 parts of DMSO and then heated at 170.degree. C.
for 10 hours. After being cooled, the reaction solution was diluted
with tetrahydrofuran and then added into an excess of methanol to
carry out reprecipitation. The separated precipitate was dried
under vacuum (at 1 mmHg (1.33 hPa), 80.degree. C. for 3 hours) to
obtain a white solid resin.
[0265] The dealcoholation conversion of the resultant resin was
determined by the foregoing method, with the result that the
dealcoholation conversion was 88.0% (a weight loss of 0.66% was
detected in the measurement by the dynamic TG method, and the
content of the lactone ring structure as determined by this method
was 17.6 weight %).
[0266] The above resin was subjected to injection molding at
220.degree. C. or 250.degree. C., with the result that considerably
much foam and silver streak were, however, seen in the molded
product.
[0267] These results are collected in Table 3.
COMPARATIVE EXAMPLE 3
[0268] The polymer solution, resultant from Referential Example 1,
was diluted with tetrahydrofuran and then added into an excess of
hexane to carry out reprecipitation. The separated precipitate was
dried under vacuum (at 1 mmHg (1.33 hPa), 80.degree. C. for 3
hours), and 10 parts of the resultant white solid resin was
dissolved into 60 parts of DMSO. To the resultant solution, 0.5
parts of p-toluenesulfonic acid monohydrate was added, and the
resultant mixture was heated at 50.degree. C. for 6 hours. After
being cooled, the reaction solution was diluted with
tetrahydrofuran and then added into an excess of methanol to carry
out reprecipitation. The separated precipitate was dried under
vacuum (at 1 mmHg (1.33 hPa), 80.degree. C. for 3 hours) to obtain
a white solid resin.
[0269] The dealcoholation conversion of the resultant resin was
determined by the foregoing method, with the result that the
dealcoholation conversion was 84.6% (a weight loss of 0.85% was
detected in the measurement by the dynamic TG method, and the
content of the lactone ring structure as determined by this method
was 16.9 weight %).
[0270] The above resin was subjected to injection molding at
220.degree. C. or 250.degree. C., with the result that considerably
much foam and silver streak were, however, seen in the molded
product.
[0271] These results are collected in Table 3.
REFERENTIAL EXAMPLE 2
[0272] A polymerization reaction was carried out in the same way as
of Referential Example 1 except that the amount of the methyl
2-(hydroxymethyl)acrylate was changed to 10 parts, and that the
amount of the methyl methacrylate was changed to 15 parts. The
polymerization conversion was 93.2%, and the content (weight ratio)
of methyl 2-(hydroxymethyl)acrylate in the resultant polymer was
40.2%. In addition, the weight-average molecular weight of this
polymer was 117,000.
EXAMPLE 10
[0273] A dealcoholation reaction and a devolatilization of the
polymer solution, resultant from Referential Example 2, were
carried out in the same way as of Example 1, and the resultant
product was extruded to obtain transparent pellets, of which the
yellowness index YI was 1.9.
[0274] The dealcoholation conversion of the resultant pellets was
determined by the foregoing method, with the result that the
dealcoholation conversion was 95.1% (a weight loss of 0.54% was
detected in the measurement by the dynamic TG method, and the
content of the lactone ring structure as determined by this method
was 38.2 weight %).
[0275] In addition, the weight-average molecular weight of the
above pellets was 42,000.
[0276] In addition, the 5% weight loss temperature, which was an
index of the heat resistance, of the above pellets was 350.degree.
C. Therefrom, it was found that the above pellets had excellent
thermal stability in the high temperature region. Incidentally, the
glass transition temperature was 141.degree. C.
[0277] In addition, the residual volatile contents in the pellets
were as follows:
[0278] Methyl methacrylate: 520 ppm
[0279] Methyl 2-(hydroxymethyl)acrylate: 60 ppm
[0280] Methanol: 690 ppm
[0281] Toluene: 90 ppm
[0282] The above pellets were subjected to injection molding at
250.degree. C. to obtain a colorless transparent molded product
(total luminous transmittance: 90.1%, haze value: 2.5%) in which
neither foam nor silver streak was seen. In addition, the impact
strength (Izod value) was measured to obtain a value of 49
N.multidot.cm/cm.sup.2 (5 kgf.multidot.cm/cm.sup.2).
[0283] These results are collected in Table 3.
EXAMPLE 11
[0284] Methyl ethyl ketone and phenylphosphonous acid were added to
the polymer solution resultant from Referential Example 2, wherein
the amount of the methyl ethyl ketone as added was 37.5 parts per
100 parts of the polymer solution, and the amount of the
phenylphosphonous acid as added was 0.01 part per 1 part of polymer
component. A dealcoholation reaction was carried out at 90.degree.
C. for 5 hours under a nitrogen stream.
[0285] A portion of the resultant reaction solution was sampled to
determine the dealcoholation conversion by the foregoing method,
with the result that the dealcoholation conversion was 88.0% (a
weight loss of 1.33% was detected in the measurement by the dynamic
TG method).
[0286] The polymer solution, resultant from the above
dealcoholation reaction, was introduced at a treatment rate of 2.0
kg/hour in terms of amount of resin into a vent type twin-screw
extruder (.PHI.=29.75 mm, L/D=30) of: barrel
temperature=250.degree. C., revolution number=100 rpm,
vacuum=10.about.300 mmHg (13.3.about.400 hPa), number of rear
vents=1, and number of fore vents=4. A devolatilization treatment
was carried out in the extruder while completing the dealcoholation
reaction, and the resultant product was extruded to obtain
transparent pellets, of which the yellowness index YI was 2.0.
[0287] The dealcoholation conversion of the resultant pellets was
determined by the foregoing method, with the result that the
dealcoholation conversion was 97.6% (a weight loss of 0.27% was
detected in the measurement by the dynamic TG method, and the
content of the lactone ring structure as determined by this method
was 39.2 weight %).
[0288] In addition, the weight-average molecular weight of the
above pellets was 80,000
[0289] In addition, the 5% weight loss temperature, which was an
index of the heat resistance, of the above pellets was 355.degree.
C. Therefrom, it was found that the above pellets had excellent
thermal stability in the high temperature region. Incidentally, the
glass transition temperature was 155.degree. C.
[0290] In addition, the residual volatile contents in the pellets
were as follows:
[0291] Methyl methacrylate: 70 ppm
[0292] Methyl 2-(hydroxymethyl)acrylate: 80 ppm
[0293] Methanol: 330 ppm
[0294] Toluene: 170 ppm
[0295] Methyl ethyl ketone: 200 ppm
[0296] The above pellets were subjected to injection molding at
250.degree. C. to stably (continuously) obtain a colorless
transparent molded product (total luminous transmittance: 89.8%,
haze value: 3.0%) in which neither foam nor silver streak was seen.
In addition, the impact strength (Izod value) was measured to
obtain a value of 118 N.multidot.cm/cm.sup.2 (12
kgf.multidot.cm/cm.sup.2).
[0297] These results are collected in Table 3.
COMPARATIVE EXAMPLE 4
[0298] The polymer solution, resultant from Referential Example 2,
was diluted with tetrahydrofuran and then added into an excess of
hexane to carry out reprecipitation. The separated precipitate was
dried under vacuum (at 1 mmHg (1.33 hPa), 80.degree. C. for 3
hours), and 10 parts of the resultant white solid resin was
dissolved into 60 parts of DMSO. To the resultant solution, 0.5
parts of p-toluenesulfonic acid monohydrate was added, and the
resultant mixture was heated at 50.degree. C. for 6 hours. After
being cooled, the reaction solution was diluted with
tetrahydrofuran and then added into an excess of methanol to carry
out reprecipitation. The separated precipitate was dried under
vacuum (at 1 mmHg (1.33 hPa), 80.degree. C. for 3 hours) to obtain
a white solid resin.
[0299] The dealcoholation conversion of the resultant resin was
determined by the foregoing method, with the result that the
dealcoholation conversion was 84.0% (a weight loss of 1.77% was
detected in the measurement by the dynamic TG method, and the
content of the lactone ring structure as determined by this method
was 33.8 weight %).
[0300] The above resin was subjected to injection molding at
220.degree. C. or 250.degree. C., with the result that considerably
much foam and silver streak were, however, seen in the molded
product.
[0301] These results are collected in Table 3.
REFERENTIAL EXAMPLE 3
[0302] A polymerization reaction was carried out in the same way as
of Referential Example 1 except that the amount of the methyl
2-(hydroxymethyl)acrylate was changed to 2.5 parts, and that the
amount of the methyl methacrylate was changed to 22.5 parts. The
polymerization conversion was 91.6%, and the content (weight ratio)
of methyl 2-(hydroxymethyl)acrylate in the resultant polymer was
10.5%. In addition, the weight-average molecular weight of this
polymer was 138,000.
EXAMPLE 12
[0303] Methyl isobutyl ketone and phenylphosphonous acid were added
to the polymer solution resultant from Referential Example 3,
wherein the amount of the methyl isobutyl ketone as added was 37.5
parts per 100 parts of the polymer solution, and the amount of the
phenylphosphonous acid as added was 0.001 part per 1 part of
polymer component. A dealcoholation reaction was carried out at
100.degree. C. for 5 hours under a nitrogen stream.
[0304] A portion of the resultant reaction solution was sampled to
determine the dealcoholation conversion by the foregoing method,
with the result that the dealcoholation conversion was 87.2% (a
weight loss of 0.37% was detected in the measurement by the dynamic
TG method) at this point of time.
[0305] A devolatilization treatment of the polymer solution,
resultant from the above dealcoholation reaction, was carried out
in the extruder in the same way as of Example 2 while completing
the dealcoholation reaction, and the resultant product was extruded
to obtain transparent pellets, of which the yellowness index YI was
1.5.
[0306] The dealcoholation conversion of the resultant pellets was
determined by the foregoing method, with the result that the
dealcoholation conversion was 97.2% (a weight loss of 0.08% was
detected in the measurement by the dynamic TG method, and the
content of the lactone ring structure as determined by this method
was 10.2 weight %).
[0307] In addition, the weight-average molecular weight of the
above pellets was 125,000.
[0308] Furthermore, the 5% weight loss temperature, which was an
index of the heat resistance, of the above pellets was 361.degree.
C. Therefrom, it was found that the above pellets had excellent
thermal stability in the high temperature region. Incidentally, the
glass transition temperature was 125.degree. C.
[0309] In addition, the residual volatile contents in the pellets
were as follows:
[0310] Methyl methacrylate: 90 ppm
[0311] Methyl 2-(hydroxymethyl)acrylate: 50 ppm
[0312] Methanol: 210 ppm
[0313] Toluene: 170 ppm
[0314] Methyl isobutyl ketone: 220 ppm
[0315] The above pellets were subjected to injection molding at
250.degree. C. to stably (continuously) obtain a colorless
transparent molded product (total luminous transmittance: 91.4%,
haze value: 1.9%) in which neither foam nor silver streak was seen.
No foam was seen in the molded product, and further, even if the
resin was allowed to reside in an injection molding machine at
250.degree. C. for 5 minutes and then subjected to injection
molding, no foam was seen in the resultant molded product. In
addition, the impact strength (Izod value) was measured to obtain a
value of 226 N.multidot.cm/cm.sup.2 (23 kgf.multidot.cm/cm.sup.2-
).
[0316] These results are collected in Table 3.
1 TABLE 1 Example 1 Example 2 Example 3 Example 4 Example 5
Properties Dealcoholation 95.8 98.4 98.0 95.3 96.7 of pellets
conversion (%) YI 2.1 5.3 2.2 2.1 5.3 Weight-average 80,000 120,000
99,000 90,000 110,000 molecular weight 5% weight loss 366 366 368
363 366 temperature (.degree. C.) Glass transition 126 134 130 126
133 temperature (.degree. C.) Residual MMA 470 60 90 520 80
volatile MHMA 50 80 80 100 110 contents MeOH 280 270 270 380 290
(ppm) Tol 90 170 180 330 170 MIBK -- 240 -- -- 240 MEK -- -- -- --
-- Properties Foam or silver streak None None None None None of
molded Total luminous 90.1 89.8 90.1 90.1 89.8 product
transmittance (%) Haze value (%) 2.5 2.8 2.3 2.7 2.8 Izod value (N
.multidot. cm/cm.sup.2) 68.6 157 147 88.3 137 MMA: methyl
methacrylate, MHMA: methyl (2-hydroxymethyl)acrylate, MeOH:
methanol, Tol: toluene, MIBK: methyl isobutyl ketone, MEK: methyl
ethyl ketone
[0317]
2 TABLE 2 Example 6 Example 7 Example 8 Example 9 Properties
Dealcoholation 98.4 97.1 98.2 98.4 of pellets conversion (%) YI 1.7
1.5 0.8 11.8 Weight-average 120,000 117,000 120,000 120,000
molecular weight 5% weight loss 367 365 366 365 temperature
(.degree. C.) Glass transition 135 135 134 135 temperature
(.degree. C.) Residual MMA 60 80 50 60 volatile MHMA 70 90 60 70
contents MeOH 190 290 240 280 (ppm) Tol 160 170 170 160 MIBK 230
240 250 230 MEK -- -- -- -- Properties Foam or silver streak None
None None None of molded Total luminous 91.0 90.9 92.5 86.5 product
transmittance (%) Haze value (%) 2.5 1.5 0.7 5.5 Izod value (N
.multidot. cm/cm.sup.2) 177 167 177 167 MMA: methyl methacrylate,
MHMA: methyl (2-hydroxymethyl)acrylate, MeOH: methanol, Tol:
toluene, MIBK: methyl isobutyl ketone, MEK: methyl ethyl ketone
[0318]
3 TABLE 3 Com- Com- Com- Com- parative parative parative parative
Example Example Example Example Example Example Example 10 11 12 1
2 3 4 Properties Dealcoholation 95.1 97.6 97.2 44.2 88.0 84.6 84.0
of pellets conversion (%) YI 1.9 2.0 1.5 0.4 0.7 1.2 1.2
Weight-average 42,000 80,000 125,000 130,000 127,000 132,000
118,000 molecular weight 5% weight loss 350 355 361 304 323 316 310
temperature (.degree. C.) Glass transition 141 155 125 128 132 130
142 temperature (.degree. C.) Residual MMA 520 70 90 -- -- -- --
volatile MHMA 60 80 50 -- -- -- -- contents MeOH 690 330 210 -- --
-- -- (ppm) Tol 90 170 170 -- -- -- -- MIBK -- -- 220 -- -- -- --
MEK -- 200 -- -- -- -- -- Properties Foam or silver streak None
None None Much Much Much Much of molded Total luminous 90.1 89.8
91.4 -- -- -- -- product transmittance (%) Haze value (%) 2.5 3.0
1.9 -- -- -- -- Izod value 49 118 226 -- -- -- -- (N .multidot.
cm/cm.sup.2) MMA: methyl methacrylate, MHMA: methyl
(2-hydroxymethyl)acrylate, MeOH: methanol, Tol: toluene, MIBK:
methyl isobutyl ketone, MEK: methyl ethyl ketone
[0319] Also from analyses such as thermal analysis of dynamic TG,
.sup.13C--NMR, and IR, it could be confirmed that the transparent
heat-resistant resin, as obtained by the production process
according to the present invention, is a transparent heat-resistant
resin in which an expected amount of lactone ring structure is
introduced. In addition, the dealcoholation conversions in the
Examples, in which the production process according to the present
invention was employed, were all high.
EXAMPLES 13 TO 17 AND COMPARATIVE EXAMPLES 5,6
[0320] The pellets resultant from Example 1 (hereinafter referred
to as pellets (A-1)) and the pellets resultant from Example 10
(hereinafter referred to as pellets (A-2)) were used, and further,
a vinyl chloride resin and an acrylonitrile-styrene resin (AS
resin) were used as thermoplastic resins (B). These were dissolved
into tetrahydrofuran in the mixing ratios (by weight) of Table 4,
and the resultant solutions were dropwise added into methanol. The
resultant reprecipitated white solids were subjected to suction
filtration and then dried to obtain thermoplastic resin
compositions. The properties of the resultant thermoplastic resin
compositions are shown in Table 4.
4 TABLE 4 Com- Com- parative parative Example Example Example
Example Example Example Example 13 14 15 16 17 5 6 A-1 20 40 60 --
20 -- -- A-2 -- -- -- 20 -- -- -- AS resin 80 60 40 80 -- 100 --
Vinyl chloride -- -- -- -- 80 -- 100 resin Heat resistance 114 119
123 115 92 110 84 (.degree. C.) Miscibility .smallcircle.
.smallcircle. .smallcircle. .smallcircle. .smallcircle. -- -- Haze
value 1.0 1.1 1.1 1.2 1.1 1.0 1.1 (%) Transparency .smallcircle.
.smallcircle. .smallcircle. .smallcircle. .smallcircle.
.smallcircle. .smallcircle.
EXAMPLES 18 TO 20 AND COMPARATIVE EXAMPLE 7
[0321] The aforementioned pellets (A-1) were used, and further, an
acrylonitrile-styrene resin (AS resin) and an
acrylonitrile-butadiene-sty- rene resin (ABS resin) were used as
thermoplastic resins (B). These were mixed in the mixing ratios (by
weight) of Table 5 with an omnimixer, and the resultant mixtures
were melt-kneaded with a twin-screw extruder of 30 mm .phi. having
a cylinder temperature as controlled to 240.degree. C., thus
obtaining thermoplastic resin compositions. The properties of the
resultant thermoplastic resin compositions are shown in Table
5.
5 TABLE 5 Com- parative Example Example Example Example 18 19 20 7
A-1 10 20 40 -- AS resin 90 20 -- -- ABS resin -- 60 60 100 Heat
resistance 112 111 114 105 (.degree. C.) Miscibility .smallcircle.
.smallcircle. .smallcircle. -- Haze value 1.0 *1 *1 *1 (%)
Transparency .smallcircle. *1 *1 *1 *1: Unmeasured because the ABS
resin itself was opaque.
EXAMPLES 21 TO 27
[0322] The pellets, resultant from Example 6, and a thermoplastic
resin, as selected from the group consisting of an
acrylonitrile-styrene resin (AS resin), a vinyl chloride resin, and
an acrylonitrile-butadiene-styren- e resin (ABS resin), were mixed
in the mixing ratios (by weight) of Tables 6 and 7 with an
omnimixer, and the resultant mixtures were melt-kneaded with a
twin-screw extruder of 30 mm .phi. having a cylinder temperature as
controlled to 240.degree. C., thus obtaining transparent
heat-resistant resin compositions. The properties of the resultant
transparent heat-resistant resin compositions were evaluated by
being measured in the aforementioned ways. The results are shown in
Tables 6 and 7 along with those of Comparative Examples 5 to 7
above for comparison.
6 TABLE 6 Exam- Example Example ple Example Example 21 22 23 24 25
Pellets of 20 40 60 20 10 Example 6 AS resin 80 60 40 -- 90 Vinyl
chloride -- -- -- 80 -- resin ABS resin -- -- -- -- -- Heat
resistance 116 122 127 96 113 (.degree. C.) Miscibility
.smallcircle. .smallcircle. .smallcircle. .smallcircle.
.smallcircle. Haze value 1.2 1.3 1.5 1.3 1.1 (%) Transparency
.smallcircle. .smallcircle. .smallcircle. .smallcircle.
.smallcircle.
[0323]
7 TABLE 7 Com- Com- Com- Exam- parative parative parative Example
ple Example Example Example 26 27 5 6 7 Pellets of 20 40 -- -- --
Example 6 AS resin 20 -- 100 -- -- Vinyl chloride -- -- -- 100 --
resin ABS resin 60 60 -- -- 100 Heat resistance 114 118 110 84 105
(.degree. C.) Miscibility .smallcircle. .smallcircle. -- -- -- Haze
value *1 *1 1.0 1.1 *1 (%) Transparency *1 *1 .smallcircle.
.smallcircle. *1 *1: Unmeasured because the ABS resin itself was
opaque.
[0324] Various details of the invention may be changed without
departing from its spirit not its scope. Furthermore, the foregoing
description of the preferred embodiments according to the present
invention is provided for the purpose of illustration only, and not
for the purpose of limiting the invention as defined by the
appended claims and their equivalents.
* * * * *