JP2009138064A - Method of manufacturing copolymer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a copolymer having excellent productivity and excellent balance of transparency, fluidity, mechanical characteristics, heat resistance and optical characteristics. <P>SOLUTION: In the method of manufacturing the copolymer, an unsaturated carboxylate monomer (A) and an unsaturated carboxylate (B) are copolymerized in the existence of a solvent (i) having 9.0 to 15.0 (cal/cm<SP>3</SP>)<SP>1/2</SP>solubility parameter δ to obtain a copolymer containing an unsaturated carboxylate monomer unit (a) and an unsaturated carboxylate monomer unit (b). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for producing a copolymer that is transparent and has high heat resistance and is excellent in fluidity, molding processability, mechanical properties, and productivity.

An acrylic resin typified by polymethyl methacrylate (PMMA) is widely used in the fields of optical materials, lenses, household goods, OA equipment, lighting equipment and the like because of its high transparency. In particular, in recent years, the use of optical materials such as light guide plates and liquid crystal display films has progressed, and it has also been developed for applications that are expected to be thinner and used at high temperatures. Optical properties are required.
As a method for improving the heat resistance of PMMA, a method of introducing a maleimide monomer has been proposed, but there are problems such as low reactivity and coloration of the resin.
Moreover, as a method for introducing an acid anhydride, a method in which methyl methacrylate and methacrylic acid are copolymerized and then a six-membered ring anhydride is generated by a cyclization reaction has been proposed (for example, Patent Documents 1 to 3). ). Since such a method can design the ratio of the monomer units of the copolymer to a certain degree of freedom, it is possible to obtain a polymer having various properties as well as improved heat resistance. . However, there is no provision for the polymerization solvent used in these methods, the production stability is improved, the recyclability of the monomer and solvent used is improved, and the fluidity, workability, optical properties are improved. Nothing satisfying the balance between characteristics and heat resistance has been found.
Japanese Examined Patent Publication No. 61-49325 JP 2003-313237 A Japanese Patent Publication No. 4-3417

  The present invention provides a method for producing a copolymer that is excellent in productivity and excellent in balance of transparency, fluidity, mechanical properties, heat resistance, and optical properties.

In the method for producing a copolymer in which an unsaturated carboxylic acid ester monomer and an unsaturated carboxylic acid monomer are copolymerized, the present inventors perform copolymerization in the presence of a specific solvent (i). The present inventors have found that a polymer having high solvent and monomer recyclability and excellent transparency, mechanical properties, heat resistance, and optical properties can be produced, and the present invention has been completed.
That is, the present invention
1. In the presence of the solvent (i) having a solubility parameter δ of 9.0 (cal / cm ³ ) ^1/2 or more and 15.0 (cal / cm ³ ) ^1/2 or less, an unsaturated carboxylic acid ester monomer (A ) And the unsaturated carboxylic acid monomer (B) to obtain a copolymer containing the unsaturated carboxylic acid ester monomer unit (a) and the unsaturated carboxylic acid monomer unit (b). A method for producing a copolymer,
2. 1. The solvent (a) contains at least one hydroxyl group in one molecule. A process for producing the copolymer according to claim 1,

3. 1. The boiling point (Y) of the solvent (a) is 100 ° C. or higher. Or 2. A process for producing the copolymer according to claim 1,
4). 1. The solvent (a) contains an alcohol having a cyclic structure. ~ 3. A method for producing the copolymer according to any one of the above,
5). 1. The solvent (a) contains cyclohexanol. ~ 4. A method for producing the copolymer according to any one of the above,
6). After the monomers (A) and (B) are copolymerized, the acid anhydride unit represented by the following general formula (1) is formed in the molecule by heat treatment at 180 to 300 ° C. and 200 Torr or less for 1 to 240 minutes. (C) is formed. ~ 5. A method for producing the copolymer according to any one of the above,

However, R1 and R2 in the formula represent a hydrogen atom and an alkyl group having 1 to 6 carbon atoms, and R1 and R2 may be the same group or different groups.
7). Further, an aromatic group-containing vinyl monomer is copolymerized as a copolymerization component. ~ 6. A method for producing the copolymer according to any one of the above,
8). 6. 1% by mass to 50% by mass of an aromatic group-containing vinyl monomer is used with respect to the mass of all monomers. A process for producing the copolymer according to claim 1,
9. In polymerizing the copolymer, the solvent (a) is present in an amount of 5 to 60% by mass when the total of all monomers and the solvent (a) is 100% by mass. ~ 8. A method for producing the copolymer according to any one of the above,
10. 1. Polymerization temperature is 50 ° C. or higher and 200 ° C. or lower. ~ 9. A method for producing the copolymer according to any one of the above,
11.1. -10. A copolymer obtained by the production method according to any one of the above,
12.11. A molded article comprising the copolymer described in
13.11. A film comprising the copolymer described in
About.

  The method for producing a copolymer according to the present invention has high productivity as compared with the prior art, such as good recyclability. Further, the obtained copolymer has high transparency and can provide a method for producing a copolymer having high heat resistance, fluidity, mechanical properties, and optical properties.

Although the manufacturing method of the copolymer of this invention is demonstrated in detail below, this invention is not limited to these aspects.
In the present invention, the monomer component before polymerization is referred to as “˜monomer”, and “monomer” may be omitted. In addition, the structural unit constituting the copolymer is referred to as “˜monomer unit”.
The copolymer obtained by the production method of the present invention is obtained by polymerizing the unsaturated carboxylic acid ester monomer (A) and the unsaturated carboxylic acid monomer (B). Other vinyl compound monomer units such as aromatic group-containing vinyl monomer units (d) can be copolymerized within a range that can be exhibited.

<Unsaturated carboxylic acid ester monomer (A)>
The unsaturated carboxylic acid ester monomer (A) that can be used in the present invention is not particularly limited as long as the effect of the present invention can be achieved, but a preferable example is represented by the following general formula (2). Monomer.

However, R3 represents a hydrogen atom or a C1-C6 alkyl group, and may have a hydroxyl group on the alkyl group. R4 represents a group having 1 to 12 carbon atoms, and may have a hydroxyl group on the carbon.
Among these, an acrylate monomer having R3 as a hydrogen atom or a methacrylic acid ester monomer having a methyl group having 1 carbon can be suitably used.
Specific examples of methacrylic acid ester monomers that can be suitably used include butyl methacrylate, ethyl methacrylate, methyl methacrylate, propyl methacrylate, isopropyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, methacrylic acid (2 -Ethylhexyl), methacrylic acid (t-butylcyclohexyl), benzyl methacrylate, methacrylic acid (2,2,2-trifluoroethyl) and the like, and a typical one is methyl methacrylate.
Specific examples of the acrylate monomer include methyl acrylate, ethyl acrylate, butyl acrylate, isopropyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, phenyl acrylate, acrylic acid (2-ethylhexyl), Examples include acrylic acid (t-butylcyclohexyl), benzyl acrylate, acrylic acid (2,2,2-trifluoroethyl), and the like.
The said (meth) acrylic acid ester monomer can also be used 1 type or in combination of 2 or more types.

<Unsaturated carboxylic acid monomer (B)>
In the copolymer of the present invention, it is necessary to copolymerize the unsaturated carboxylic acid monomer (B). The unsaturated carboxylic acid monomer can be represented by the general formula (3).

However, R5 represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and may have a hydroxyl group on the alkyl group.
Among them, an acrylic acid monomer in which R5 is a hydrogen atom or a methacrylic acid monomer in which a carbon group has a methyl group can be suitably used. Examples thereof include methacrylic acid, acrylic acid, itaconic acid, maleic acid. Examples thereof include acid, fumaric acid, cinnamic acid and the like, and methacrylic acid or acrylic acid can be preferably used, and methacrylic acid can be more preferably used.
These unsaturated carboxylic acid monomers can be used alone or in combination.
The proportion of copolymerization of the unsaturated carboxylic acid monomer (B) is based on 100 parts by mass of the total monomer amount in consideration of the heat resistance, processability, optical properties, productivity, etc. of the obtained copolymer. It is preferably 1 part by weight or more and 50 parts by weight or less, more preferably 5 parts by weight or more and 40 parts by weight or less, still more preferably 10 parts by weight or more and 40 parts by weight or less, and particularly preferably 10 parts by weight or more and 35 parts by weight or less. Hereinafter, it is particularly preferably 15 parts by mass or more and 35 parts by mass or less, and most preferably 20 parts by mass or more and 30 parts by mass or less.

<Aromatic group-containing vinyl monomer (D)>
In the present invention, the aromatic group-containing vinyl monomer (D) can be copolymerized. The aromatic group-containing vinyl monomer can be represented by the following general formula (4).

However, R6 represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and may have a hydroxyl group on the alkyl group. Moreover, n in a formula represents the integer of 0-5. R7 is a group selected from a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an aryl group having 1 to 8 carbon atoms, and an aryl group having 1 to 8 carbon atoms. And R7 may all be the same group or all different groups. Further, R7 may form a ring structure.
Examples include styrene, o-methyl styrene, m-methyl styrene, p-methyl styrene, 2,4-dimethyl styrene, 2,5-dimethyl styrene, 3,4-dimethyl styrene, 3,5-dimethyl styrene, Styrene monomers such as p-ethylstyrene, m-ethylstyrene, о-ethylstyrene, p-tert-butylstyrene, isopropenyl benzene (α-methylstyrene), 1-vinylnaphthalene, 2-vinylnaphthalene, 1 , 1-diphenylethylene, isopropenyltoluene, isopropenylethylbenzene, isopropenylpropylbenzene, isopropenylbutylbenzene, isopropenylpentylbenzene, isopropenylhexylbenzene, isopropenyloctylbenzene, etc., and the necessary properties for the copolymer By Can be selected as appropriate. Preferred monomers include styrenic monomers, more preferably styrene, isopropenylbenzene, and still more preferably styrene. The aromatic group-containing vinyl monomers can be used alone or in combination of two or more.

When the aromatic group-containing vinyl monomer (D) is copolymerized, the optimum amount can be determined according to the optical properties, heat resistance and processability required for the resulting copolymer. In consideration of the above, it is preferable that the total monomer amount is 100 parts by mass, preferably 0.5 parts by mass or more and 50 parts by mass or less, more preferably more than 1 part by mass and 45 parts by mass or less. Is 2 to 45 parts by mass, particularly preferably 4 to 40 parts by mass, and most preferably 4 to 37 parts by mass.
In addition, when the content of the aromatic group-containing vinyl monomer is small relative to the unsaturated carboxylic acid monomer, the solubility in a solvent tends to decrease, the solution viscosity at the time of polymerization, From the viewpoint of heat resistance, the mass% ratio between the unsaturated carboxylic acid monomer and the aromatic group-containing vinyl monomer is 0.25 ≦ (unsaturated carboxylic acid monomer) / (aromatic group-containing vinyl monomer). (Mer)) is preferably in the range of ≦ 9.

<Other vinyl monomers (E)>
In the present invention, vinyl monomers other than (A), (B) and (D) (hereinafter referred to as other vinyl monomers) can be used as long as the effects of the present invention are not impaired. . Other vinyl monomers include vinyl cyanides such as acrylonitrile and methacrylonitrile, unsaturated carboxylic acid anhydrides such as maleic anhydride and itaconic anhydride, N-methylmaleimide, N-ethylmaleimide, N -Maleimides such as phenylmaleimide and N-cyclohexylmaleimide, and amides such as acrylamide and methacrylamide. In the case of containing other vinyl-based monomers, it is preferable to be 0.1 to 50 parts by mass with respect to 100 parts by mass of the total amount of monomers in consideration of optical properties, heat resistance, and processability. Preferably it is 0.1-40 mass parts, More preferably, it is 0.5-35 mass parts, Especially preferably, it is 1-30 mass parts, Most preferably, it is 1-25 mass parts.

<Polymerization method>
As the polymerization method of the copolymer of the present invention, conventionally known methods such as bulk polymerization, solution polymerization, emulsion polymerization, suspension polymerization and the like can be used, and it is possible to reduce the mixing of minute foreign matters. Bulk polymerization and solution polymerization without using a suspending agent or an emulsifier are preferred.

<Solvent (I)>
In the production of the copolymer in the present invention, particularly when solution polymerization or bulk polymerization is performed, it is considered that stable operation becomes difficult if the polymer is precipitated when the solubility of the resulting copolymer in the solvent is low. Therefore, in consideration of the solubility of the copolymer in the solvent, the solubility parameter δ of the solvent (a) needs to be 9.0 to 15.0 (cal / cm ³ ) ^1/2 . Preferably 9.2 to 14.0 (cal / cm ³ ) ^1/2 , more preferably 9.3 to 13.5 (cal / cm ³ ) ^1/2 , particularly preferably 9.4 to 13.0 ( cal / cm ³ ) ^1/2 , particularly preferably 9.7 to 12.8 (cal / cm ³ ) ^1/2 . The value of the solubility parameter and the method for obtaining the value are described in, for example, K. P. P118-P118 in Non-Patent Document “Journal of Paint Technology Vol. 42, No. 541, February 1970”. L. Hoy “New Values of the Solubility Parameters From Vapor Pressure Data” For example, Brandrup et al., “Polymer Handbook Fourth Edition” P-VII / 675-P714 can be referred to. 1 (cal / cm ³ ) ^1/2 is approximately 0.49 (MPa) ^1/2 .

  In the production of the copolymer in the present invention, when a solvent that does not contain a hydroxyl group, such as aromatic hydrocarbons or ketones, is used, when operating at a practically useful degree of polymerization during copolymer production, The degree of polymerization may not be increased because the molecular weight and molecular weight distribution tend to be difficult to control due to the precipitation of molecular weight components. In particular, when an unsaturated carboxylic acid monomer is used in an amount of 15% by mass or more, a high molecular weight component may be precipitated, but this tendency is remarkable when an aromatic group-containing vinyl monomer is not copolymerized. When it is necessary to consider productivity, it is preferable to use a solvent containing at least one hydroxyl group as represented by the following general formula (5).

R8 in the formula represents an alkyl group having 1 to 15 carbon atoms, and the substituent on the carbon is at least one group selected from a hydrogen atom and a hydroxyl group. Further, it may contain an ether bond.
Further, since unsaturated carboxylic acid monomers tend to have high polymerizability, self-polymerization may occur at room temperature to high temperature when a polymerization inhibitor is not added or when the addition amount is small. When the solvent and monomer recovered from the reaction system are recycled, separation operation can be performed using a rectifying column, but the polymerization of unsaturated carboxylic acid monomer proceeds in the rectifying column and is recycled. In addition, the device may be damaged due to the precipitation and solidification of the polymer. When it is necessary to consider the recyclability of the monomer or solvent to be used, it is preferable to use a solvent (a) containing at least one hydroxyl group.

  An example of the solvent (i) is methanol, ethanol, propanol, butanol, pentanol, hexanol, heptanol, capryl alcohol, lauryl alcohol, myristyl alcohol, cyclopentanol, cyclohexanol, cycloheptanol, 2-methylcyclohexanol. 3-methylcyclohexanol, 4-methylcyclohexanol, 2-ethylcyclohexanol, 3-ethylcyclohexanol, 4-ethylcyclohexanol, 2,3-dimethylcyclohexanol, 2,4-dimethylcyclohexanol, 2,5 -Alcohols having one hydroxyl group such as dimethylcyclohexanol, 2,6-dimethylcyclohexanol, 3,4-dimethylcyclohexanol, 3,5-dimethylcyclohexanol And, ethylene glycol, alcohols containing multiple hydroxyl groups such as glycerin, ethers bond-containing alcohols such as methyl cellosolve.

Among them, secondary alcohols are preferable, and alcohols having a cyclic structure are more preferable. Among them, cyclohexanol having excellent miscibility with an unsaturated carboxylic acid monomer is an unsaturated carboxylic acid monomer that is an organic acid. It is particularly preferable also from the viewpoint of preventing metal corrosion due to the kind.
Further, the amount of water contained in the solvent (a) is preferably 5% or less, more preferably 3% or less, still more preferably 0.01 to 2%, and particularly preferably 0.1 to 2%. .
In addition, unsaturated carboxylic acid monomers tend to have a higher boiling point compared to acrylic ester monomers and aromatic group-containing vinyl monomers, and the rectifying tower is used for the separation of the recycle liquid. The lower portion tends to remain at a high concentration, and the polymerization proceeds with the unsaturated carboxylic acid monomer at the lower portion of the rectifying column, which may impair the recyclability of the monomer or solvent. When the recyclability of the monomer or solvent is required, it can be resolved by using a solvent containing at least one hydroxyl group. However, when higher recyclability is required, the boiling point of the solvent must be 100 ° C. or higher. It is preferably 100 ° C. or higher and 200 ° C. or lower, more preferably 110 ° C. or higher and 200 ° C. or lower, particularly preferably 120 ° C. or higher and 190 ° C. or lower, and particularly preferably 130 ° C. or higher and 190 ° C. or lower.

Furthermore, the difference between the boiling point (X) of the monomer having the highest boiling point among the monomers used and the boiling point (Y) of the solvent (i) used is −50 ° C. ≦ (XY) ≦ 40 ° C. More preferably, −40 ° C. ≦ (XY) ≦ 30 ° C., more preferably −40 ° C. ≦ (XY) ≦ 20 ° C., particularly preferably −30 ° C. ≦ (XY). ≦ 20 ° C., particularly preferably −25 ° C. ≦ (XY) ≦ 15 ° C., most preferably −15 ° C. ≦ (XY) ≦ 10 ° C.
In performing solution polymerization or bulk polymerization, the solubility of the copolymer with respect to the solvent (a) used in the present invention is preferably 0.1 g / 100 mL or more in consideration of production stability, and preferably 1 g / More preferably, it exceeds 100 mL. Further, it is preferably 2 g / 100 mL or more.

  Moreover, when the recycling solution recovery process of a polymerization solution, piping corrosivity, etc. are considered, it is preferable that the solubility with respect to the water of solvent (a) is 0.7 g / 100 mL or more and 100 g / 100 mL or less. More preferably 1.0 g / 100 mL to 80 g / 100 mL, still more preferably 1.0 g / 100 mL to 50 g / 100 mL, particularly preferably 1.0 g / 100 mL to 25 g / 100 mL, particularly preferably 1.0 g / 100 mL or more 15 g / 100 mL or less, most preferably 1.0 g / 100 mL or more and 10 g / 100 mL or less.

<Solvent (a) addition amount>
If the amount of the solvent (i) used in the present invention is too large, the amount of the copolymer in the polymerization solution decreases, so the productivity decreases, and if it is too small, the viscosity of the polymerization solution increases and the heating machine increases. It is necessary to take measures such as increasing the temperature of the product, which tends to increase production costs. If these problems are not considered as problems, the addition amount of the solvent (a) that can be polymerized may be appropriately selected. Usually, the total of all the monomer components and the solvent (a) is taken into consideration in consideration of productivity and production cost. When the amount is 100% by mass, the amount of the solvent (A) is preferably 5% by mass or more and 60% by mass or less. More preferably, they are 5 to 50 mass%, More preferably, they are 10 to 45 mass%, Most preferably, they are 15 to 40 mass%.

<Polymerization temperature, time>
The polymerization temperature in the production of the copolymer of the present invention may be a temperature at which polymerization proceeds, but is preferably 50 ° C. or higher and 200 ° C. or lower, more preferably 90 ° C. or higher and 200 ° C. or lower from the viewpoint of productivity. It is. More preferably, they are 100 degreeC or more and 200 degrees C or less, More preferably, they are 100 degreeC or more and 180 degrees C or less, Especially preferably, they are 110 degreeC or more and 170 degrees C or less, Especially preferably, they are 120 degreeC or more and 160 degrees C. The polymerization time is not particularly defined as long as the required degree of polymerization can be obtained, but is preferably 0.5 hours or more and 6 hours or less, more preferably 1 hour from the viewpoint of productivity. It is 5 hours or less, more preferably 1 hour or more and 3 hours or less.

<Dissolved oxygen concentration>
When the copolymer of the present invention is produced, the dissolved oxygen concentration in the polymerization solution is preferably 10 ppm or less. The dissolved oxygen concentration is, for example, a value measured using a dissolved oxygen meter DO meter B-505 (manufactured by Iijima Electronics Co., Ltd.). As a method for lowering the dissolved oxygen concentration, a method of bubbling an inert gas in the polymerization solution, and an operation of releasing the pressure after pressurizing the container containing the polymerization solution with an inert gas to about 0.2 MPa before the polymerization are repeated. A method such as a method and a method of passing an inert gas in a container containing a polymerization solution can be appropriately selected.

<Copolymer molecular weight>
The molecular weight distribution range of the copolymer is such that the ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is from 1.5 to 3.0 from the viewpoint of processing fluidity and mechanical strength. Preferably there is. More preferably, it is 1.6-2.7, More preferably, it is the range of 1.6-2.4.
The ratio (Mw / Mn) between the weight average molecular weight (Mw) and the number average molecular weight (Mn) in the present invention is a value determined by PMMA conversion using gel permeation chromatography (GPC).
The weight average molecular weight (Mw) measured by GPC is preferably 50,000 to 300,000, more preferably 5 to 250,000, still more preferably 7 to 220,000 from the balance of fluidity, heat resistance, stretching stability, and the like. Most preferably, it is 80-200,000.

<Polymerization initiator>
In the polymerization of the copolymer according to the present invention, a polymerization initiator may be used for the purpose of adjusting the degree of polymerization. In the present invention, examples of polymerization initiators that can be used include di-t-butyl peroxide, lauroyl peroxide, stearyl peroxide, benzoyl peroxide, and t-butyl peroxyneo when radical polymerization is performed. Decanate, t-butylperoxypivalate, dilauroyl peroxide, dicumyl peroxide, t-butylperoxy-2-ethylhexanoate, 1,1-bis (t-butylperoxy) -3,3 Organic peroxides such as 1,5-bis (t-butylperoxy) cyclohexane, azobisisobutyronitrile, azobisisovaleronitrile, 1,1-azobis (1-cyclohexanecarbox) Nitrile) 2,2'-azobis-4-methoxy-2,4-azo Azo-based general radical polymerization initiators such as sisobutyronitrile, 2,2′-azobis-2,4-dimethylvaleronitrile, 2,2′-azobis-2-methylbutyronitrile can be listed. . These may be used alone or in combination of two or more. A combination of these radical initiators and an appropriate reducing agent may be used as a redox initiator. These initiators are generally used in the range of 0 to 1 part by mass with respect to 100 parts by mass of the monomer mixture, and are appropriately selected in consideration of the polymerization temperature and the initiator half-life. Can do.

In particular, when polymerization is performed at a high temperature of 90 ° C. or higher, solution polymerization is common, so that 10
Preference is given to peroxides, azobis initiators, etc. that have a time half-life temperature of 80 ° C. or higher and are soluble in the organic solvent used. Specifically, 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, cyclohexane peroxide, 2,5-dimethyl-2,5-di (benzoylperoxy) hexane, , 1-azobis (1-cyclohexanecarbonitrile), 2- (carbamoylazo) isobutyronitrile and the like. These initiators are preferably used in the range of 0 to 1% by mass with respect to 100% by mass of the total monomer amount, for example.
When the solution polymerization method is selected, the type and amount of the polymerization initiator may be appropriately determined so that the solid content in the polymerization solution becomes 10 to 60% by mass in consideration of the viscosity of the polymerization solution.

<Molecular weight control>
In the production of the copolymer according to the present invention, the molecular weight can be controlled as long as the object of the present invention is not impaired. For example, there are methods using chain transfer agents such as alkyl mercaptans, dimethylacetamide, dimethylformamide and triethylamine, and iniferters such as dithiocarbamates, triphenylmethylazobenzene and tetraphenylethane derivatives. The molecular weight can be adjusted by adjusting the amount of these additives. When these additives are used, alkyl mercaptans are preferably used from the viewpoint of handleability and stability. For example, n-butyl mercaptan, n-octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, n-tetra Examples include decyl mercaptan, n-octadecyl mercaptan, 2-ethylhexyl thioglycolate, ethylene glycol dithioglycolate, trimethylolpropane tris (thioglycolate), pentaerythritol tetrakis (thioglycolate) and the like.
These can be appropriately added according to the required molecular weight, but generally used in the range of 0.001 to 3 parts by mass with respect to 100 parts by mass of the total monomer mixture.
Examples of other molecular weight control methods include a method of changing the polymerization method, a method of adjusting the amount of the polymerization initiator, and a method of changing the polymerization temperature.
These molecular weight control methods may be used alone, or two or more methods may be used in combination.

<Acid anhydride monomer unit (c)>
In the copolymer of the present invention, when copolymerizing an unsaturated carboxylic acid monomer, from the balance of heat stability, the photoelastic coefficient of the copolymer and stretch retardation and heat resistance, a cyclization reaction is performed, It is preferable to form the structural unit represented by the general formula (1).
The structural unit represented by the general formula (1) is heated in the presence or absence of a catalyst to dehydrate the unsaturated carboxylic acid monomer, or the unsaturated carboxylic acid monomer and the unsaturated carboxylic acid. It can be obtained by an intramolecular cyclization reaction by dealcoholization reaction from an acid ester.
The method for causing such an intramolecular cyclization reaction is not particularly limited. For example, a method using an extruder having a vent port or a devolatilization tank under an inert gas atmosphere such as nitrogen or argon or under reduced pressure is used. Methods and the like.
Preferred examples of the apparatus include a flash tank, a twin screw extruder, a single screw extruder, a twin / single screw combined continuous kneading extruder, a multi-screw extruder having three or more axes, a kneader, and the like. More than one species may be used in combination.

The temperature at the time of devolatilization by the above method can be appropriately selected according to the desired copolymer composition, the amount of unreacted monomer and the amount of solvent, and is the temperature at which intramolecular cyclization occurs. Although there will be no restriction | limiting in particular if it exists, Preferably it is 180-300 degreeC, More preferably, it is 200-300 degreeC, More preferably, it is 200-280 degreeC, Most preferably, it is 220-280 degreeC.
Moreover, the heating time in the case of performing heat devolatilization and / or cyclization reaction by the above method can be appropriately set according to the desired copolymer composition, and is usually 1 to 240 minutes, preferably 1 to 150 minutes, more preferably 1 to 120 minutes, particularly preferably 2 to 90 minutes, particularly preferably 3 to 60 minutes, and particularly preferably 5 to 60 minutes.

When using an extruder, in order to ensure the heating time, the ratio of screw diameter (D) to screw length (L) is preferably L / D = 20 or more, more preferably 30 or more, particularly preferably. It is preferable to set it to 40 or more. Moreover, it is preferable that L / D is 120 or less practically.
Further, when the heat devolatilization and / or cyclization reaction is carried out under reduced pressure, it is preferably 200 Torr or less, more preferably 150 Torr or less, still more preferably 100 Torr or less, particularly preferably 50 Torr, in view of devolatilization efficiency and the like. It is as follows. Moreover, it is preferable that it is 1 Torr or more practically.

In the copolymer according to the present invention, when the acid anhydride monomer unit (c) is formed, at least one selected from acids, alkalis and salts can be added as a catalyst for promoting the cyclization reaction. The amount of the cyclization catalyst added is not particularly specified as long as it does not impair the purpose of the present application, but is preferably smaller from the viewpoint of the transparency and mechanical strength of the resulting copolymer. Specifically, it is preferably 1 part by mass or less, more preferably 0.5 part by mass or less, and still more preferably 0.1 part by mass or less. If an example of the catalyst used suitably is given, hydrochloric acid, a sulfuric acid, phosphoric acid, phosphorous acid, p-toluenesulfonic acid, phenylphosphonic acid etc. will be mentioned as an acid catalyst. Examples of the basic catalyst include metal hydroxides, amines, imines, alkali metal derivatives, alkaline earth metal derivatives, and the like. Examples of the salt catalyst include metal carbonates, metal sulfates, metal acetates, and metal stearates.
From the viewpoint of the reaction promoting effect of the cyclization reaction, the transparency of the copolymer, and the colorability, an alkali-based or salt-based catalyst can be preferably used, and the cyclization catalyst may be used alone or in combination of two or more. You can also.

<Composition ratio of each monomer unit in the copolymer>
The mass% ratio of each structural unit of the copolymer in the present invention includes the unsaturated carboxylic acid ester unit (a) and the unsaturated carboxylic acid monomer unit (b). When the total amount is 100% by mass, the content of the component (b) is preferably 1% by mass or more and 70% by mass or less.
Moreover, when (a) component and (b) component and an acid anhydride unit (c) are contained, each abundance ratio considers the balance of heat resistance, fluidity | liquidity, workability, mechanical characteristics, and optical characteristics. When the total amount of the components (a), (b) and (c) is 100% by mass, the content of the component (b) is 1% by mass to 50% by mass, more preferably 1% by mass or more. It is 40 mass% or less, More preferably, it is 2 mass% or more and 30 mass% or less, and (b) component and (c) component and mass ratio are 2 <= (c) / (b) <= 30. preferable.

When the copolymer according to the present invention further contains an aromatic group-containing vinyl monomer unit (d), the content of the component (d) in the copolymer provides desired mechanical properties and heat resistance. As long as the total is 100% by mass, the component (d) is 1 to 50 when the total of the components (a), (b), (c) and (d) is 100% by mass. It is preferable that it is mass%, More preferably, it is 2-45 mass%, More preferably, it is 3-40 mass%.
In particular, when it is necessary to highly balance optical properties such as photoelastic coefficient and retardation, heat resistance, and processing fluidity, the blending ratio of the component (d) and the component (b) is 1 ≦ (d) / It is preferable that (b) ≦ 10.

<Combination with other resins>
The copolymer produced in the present invention can be used in combination with a conventionally known resin. The resin to be used is not limited at all, and a known curable resin or thermoplastic resin is preferably used. For example, as the thermoplastic resin, polypropylene resin, polyethylene resin, polystyrene resin, syndiotactic polystyrene resin, ABS resin, resin, AS resin, BAAS resin, MBS resin, AAS resin, Biodegradable resin, Polycarbonate-ABS resin alloy, Polybutylene terephthalate, Polyethylene terephthalate, Polypropylene terephthalate, Polytrimethylene terephthalate, Polyethylene naphthalate, Polyalkylene arylate resin, Polyamide resin, Polyphenylene ether resin, Polyphenylene sulfide Examples thereof include resins and phenolic resins. In particular, AS resin and BAAS resin are preferable for improving fluidity, ABS resin and MBS resin are preferable for improving impact resistance, and polyester resin is preferable for improving chemical resistance. In addition, polyphenylene ether resins, polyphenylene sulfide resins, phenol resins, and the like can be expected to have an effect of improving flame retardancy.

Further, as curable resins, unsaturated polyester resins, vinyl ester resins, diallyl phthalate resins, epoxy resins, cyanate resins, xylene resins, triazine resins, urea resins, melamine resins, benzoguanamine resins, urethane resins, oxetane resins, ketone resins. Alkyd resin, furan resin, styrylpyridine resin, silicone resin, synthetic rubber and the like.
Other resins that can be used in the present invention may be used singly or in combination of two or more resins.

<Additives>
In the copolymer produced in the present invention, other additives such as a plasticizer, an antioxidant, and the like are added as long as the effects of the present invention are not impaired in order to impart other characteristics such as rigidity and dimensional stability. Stabilizers such as UV absorbers, heat stabilizers, light stabilizers, flame retardants, flame retardant aids, curing agents, curing accelerators, antistatic agents, conductivity-imparting agents, stress relaxation agents, release agents, crystallization Accelerator, hydrolysis inhibitor, lubricant, impact imparting agent, slidability improver, compatibilizer, nucleating agent, reinforcing agent, reinforcing agent, flow modifier, dye, sensitizer, coloring pigment, rubbery Polymers, thickeners, anti-settling agents, anti-sagging agents, fillers, antifoaming agents, coupling agents, rust inhibitors, antibacterial / antifungal agents, antifouling agents, conductive polymers, etc. may be added. Is possible.

  Examples of the heat stabilizer that can be added to the copolymer produced in the present invention include antioxidants such as hindered phenol antioxidants and phosphorus processing stabilizers, and preferably hindered phenols. It is a system antioxidant. Specifically, pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, thiodiethylenebis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) ) Propionate, octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, N, N′-hexane-1,6-diylbis [3- (3,5-di-tert-butyl) -4-hydroxyphenylpropionamide, 3,3 ′, 3 ″, 5,5 ′, 5 ″ -hexa-tert-butyl-a, a ′, a ″-(mesitylene-2,4,6- Triyl) tri-p-cresol, 4,6-bis (octylthiomethyl) -o-cresol, 4,6-bis (dodecylthiomethyl) -o-cresol, ethyl Bis (oxyethylene) bis [3- (5-tert-butyl-4-hydroxy-m-tolyl) propionate, hexamethylenebis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 1,3,5-tris (3,5-di-tert-butyl-4-hydroxybenzyl) -1,3,5-triazine-2,4,6 (1H, 3H, 5H) -trione, 1,3 , 5-tris [(4-tert-butyl-3-hydroxy-2,6-xylin) methyl] -1,3,5-triazine-2,4,6 (1H, 3H, 5H) -trione, 2, 6-di-tert-butyl-4- (4,6-bis (octylthio) -1,3,5-triazin-2-ylamine) phenol and the like, more preferably pentaerythritol [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate.

Examples of ultraviolet absorbers that can be added to the copolymer produced in the present invention include benzotriazole compounds, benzotriazine compounds, benzoate compounds, benzophenone compounds, oxybenzophenone compounds, phenol compounds, and oxazoles. Compounds, malonic acid ester compounds, cyanoacrylate compounds, lactone compounds, salicylic acid ester compounds, benzoxazinone compounds, and the like, preferably benzotriazole compounds and benzotriazine compounds. These may be used alone or in combination of two or more.
The ultraviolet absorber that can be added in the present invention preferably has a vapor pressure (P) at 20 ° C. of 1.0 × 10 ⁻⁴ Pa or less, more preferably 1 from the viewpoint of moldability. 0.0 × 10 ⁻⁶ Pa or less, particularly preferably 1.0 × 10 ⁻⁸ Pa or less. “Excellent molding processability” means, for example, that there is little adhesion of a low molecular compound to a roll during film molding. If it adheres to the roll, for example, it may adhere to the surface of the molded body and deteriorate the appearance and optical properties, which is undesirable as an optical material.

Moreover, it is preferable that melting | fusing point (Tm) of an ultraviolet absorber (c) is 80 degreeC or more, More preferably, it is 100 degreeC or more, More preferably, it is 130 degreeC or more, Most preferably, it is 160 degreeC or more.
The UV absorber that can be added in the present invention preferably has a weight loss rate of 50% or less, more preferably 30% or less when the temperature is increased from 23 ° C. to 260 ° C. at a rate of 20 ° C./min. More preferably, it is 15% or less, more preferably 10% or less, and particularly preferably 5% or less.

<Additives and other resin kneading methods>
When the copolymer obtained in the present invention is processed or combined with various additives and other resins, the kneading method may be a conventionally known method and is not particularly defined. For example, it can be kneaded and produced using a kneader such as an extruder, a heating roll, a kneader, a roller mixer, a Banbury mixer and the like. Among these, kneading with an extruder is preferable in terms of productivity. The kneading temperature may be in accordance with the preferred processing temperature of the base resin, and as a guideline is in the range of 140 to 360 ° C, preferably in the range of 180 to 330 ° C.

<Molding method>
Moreover, it is preferable that the molded object containing the copolymer obtained by the manufacturing method of this invention is a film. The molding containing the copolymer is a known method such as injection molding, sheet molding, blow molding, injection blow molding, inflation molding, T-die molding, press molding, extrusion molding, foam molding, film molding by casting method, etc. And secondary processing molding methods such as pressure forming and vacuum forming can be used.
Moreover, when mix | blending with curable resin, after mixing the component for manufacturing a resin composition without a solvent or using the solvent which can be mixed uniformly as needed, a solvent is removed. A method may be used in which a resin mixture is obtained, cast into a mold and cured, cooled, and taken out of the mold to obtain a molded product. It can also be cast into a mold and cured by hot pressing. The solvent for dissolving each component is not particularly limited as long as various materials can be mixed uniformly and the effects of the present invention are not impaired by use. Examples include toluene, xylene, acetone, methyl ethyl ketone, methyl butyl ketone, diethyl ketone, cyclopentanone, cyclohexanone, dimethylformamide, methyl cellosolve, methanol, ethanol, n-propanol, iso-propanol, n-butanol, n-pen. Examples include tanol, n-hexanol, cyclohexanol, n-hexane, and n-pentane.

  Another example is a method of kneading and manufacturing using a kneader such as a heating roll, kneader, Banbury mixer, or extruder, followed by cooling, pulverization, and molding by transfer molding, injection molding, compression molding, or the like. it can. The curing method varies depending on the curing agent used, but is not particularly limited. Examples include thermal curing, light curing, UV curing, pressure curing, moisture curing, and the like. The order of mixing the components is not particularly limited as long as the effect of the present invention can be achieved.

<Application>
The molded article made of the copolymer produced according to the present invention can be used for household goods, OA equipment, AV equipment, battery electrical equipment, lighting equipment, automotive parts use, housing use, liquid crystal display, plasma display, organic EL Light guide plate, diffuser plate, polarizing plate protective film, quarter wave plate, half wave plate, viewing angle control film, liquid crystal optical compensation film, etc. used in displays such as displays, field emission displays, rear projection televisions, etc. It can be suitably used for a phase difference film, a display front plate, a display substrate, a lens, a touch panel, etc., and a transparent substrate used for solar cells. In addition, in the fields of optical communication systems, optical switching systems, and optical measurement systems, they can also be used for waveguides, lenses, optical fibers, optical fiber coating materials, LED lenses, lens covers, and the like. It can also be used as a modifier for other resins.
The molded body made of the copolymer produced according to the present invention can be subjected to surface functionalization treatment such as antireflection treatment, transparent conductive treatment, electromagnetic wave shielding treatment, and gas barrier treatment.

EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to the following examples.
(1) Measurement of glass transition temperature (Tg) Using a differential scanning calorimeter DSC-7 type (manufactured by Perkin Elmer), measurement was performed at a heating rate of 20 ° C./min in a nitrogen atmosphere.
(2) Fluidity (melt flow rate: MFR)
Based on ASTM-D1238, the measurement was performed at 230 ° C./3.8 kg load.
(3) Molecular weight distribution (Mw / Mn)
Tosoh's gel permeation chromatography (HLC-8120 + 8020) column and Tosoh's TSK Super HH-M (2) + Super H2500 (1) are arranged in series, and the detector is RI, and the measurement sample is 0 0.02 g of methacrylic resin was dissolved in 20 cc of THF solvent, and the elution time and strength were measured at an injection amount of 10 ml and a development flow rate of 0.3 ml / min. The weight average molecular weight (Mw) and the number average molecular weight (Mn) are obtained based on a calibration curve using a standard sample of a monodispersed methacrylic resin manufactured by GL Sciences, and the molecular weight distribution is calculated as Mw / Mn. did.

(4) Total light transmittance (optical characteristics)
It was measured using a turbidimeter model: 1001DP manufactured by Nippon Denshoku Industries Co., Ltd.
(5) Impact resistance A test piece of about 50 mm x about 50 mm x thickness of about 0.4 mm was prepared, and about 10 mm each on the left and right and top and bottom of a "round" mold with holes of about 30 mm x about 30 mm. As shown in the figure, it was affixed with double-sided tape, about 12.1 g of an iron ball was dropped there, and the height (cm) at which it was not broken was calculated for comparison of impact resistance.
(6) Tensile in the path of the measurement the measurement beam of the photoelastic coefficient (C _R) apparatus (Imoto Seisakusho) arranged, with RETS-RFI (manufactured by Otsuka Electronics) The birefringence while applying a tensile stress to the test piece Measured. The strain rate during stretching was 0.3% / min (between chucks: 30 mm, chuck moving speed 0.1 mm / min), and the specimen width was 10 mm. The absolute value of birefringence (| Δn |) in the strain range of 0.5 to 1.0% of the specimen at 25 ° C. is plotted as the y-axis and the tensile stress (σ _R ) as the x-axis, and is linear by least square approximation. The slope of the straight line of the region was obtained, and the absolute value (| C _R |) of the photoelastic coefficient was calculated.

[Example 1]
53 parts by weight of methyl methacrylate, 5 parts by weight of styrene, 12 parts by weight of methacrylic acid, 30 parts by weight of cyclohexanol (water content: 2%, solubility parameter δ = 11.4), 1,1-di (tert-butyl par Oxy) A liquid mixture consisting of 50 ppm of cyclohexane and 1400 ppm of n-octyl mercaptan was prepared, and nitrogen gas was bubbled for 10 minutes. This mixture was continuously fed to a jacketed complete mixing reactor having an internal volume of 3 L at a rate of 1.5 L / hr for polymerization. When the reaction was conducted at a polymerization temperature of 135 ° C. for 2 hours, the polymer was completely dissolved, and the solid content of the polymer contained in the polymerization solution was 40% by mass. This polymerization solution was immediately and continuously passed through a heater and supplied to the devolatilization tank. This devolatilization tank was retained at 255 ° C. and 25 Torr for 40 minutes, thereby generating unreacted monomers and a solvent and generating a six-membered cyclic acid anhydride. Unreacted monomers and solvent were recovered through a recovery line.
As a result of composition analysis of the obtained polymer, it was 70% by mass of methyl methacrylate unit, 10% by mass of styrene unit, 3% by mass of methacrylic acid unit, 17% by mass of 6-membered cyclic anhydride unit, and melt flow rate (ASTM- D1238; 230 ° C., 3.8 kg load) was 0.9 g / 10 min, Mw / Mn = 1.9, and Tg = 130 ° C.
The recovered unreacted monomer and solvent were heated to reflux at 90 ° C. for 3 hours in a nitrogen atmosphere, but no solid was formed.

[Example 2]
51.8 parts by weight of methyl methacrylate, 3.5 parts by weight of styrene, 14.7 parts by weight of methacrylic acid, 30 parts by weight of cyclohexanol, 50 ppm of 1,1-di (tert-butylperoxy) cyclohexane, 1500 ppm of n-octyl mercaptan A mixed solution was prepared and nitrogen gas was bubbled for 10 minutes. This mixture was continuously fed to a jacketed complete mixing reactor having an internal volume of 3 L at a rate of 1.5 L / hr for polymerization. When the reaction was conducted at a polymerization temperature of 135 ° C. for 2 hours, the polymer was completely dissolved, and the solid content of the polymer contained in the polymerization solution was 40% by mass. This polymerization solution was immediately and continuously passed through a heater and supplied to the devolatilization tank. This devolatilization tank was kept at 255 ° C. and 25 Torr for 30 minutes, thereby generating unreacted monomers and a solvent, and generating a six-membered cyclic acid anhydride. Unreacted monomers and solvent were recovered through a recovery line.
As a result of composition analysis of the obtained polymer, it was found that the methyl methacrylate unit was 68.9% by mass, the styrene unit was 6.8% by mass, the methacrylic acid unit was 3.2% by mass, and the 6-membered cyclic anhydride unit was 21.1% by mass. Yes, the melt flow rate (ASTM-D1238; 230 ° C., 3.8 kg load) was 0.9 g / 10 min, Mw / Mn = 1.9, and Tg = 133 ° C.
The recovered unreacted monomer and solvent were heated to reflux at 90 ° C. for 3 hours in a nitrogen atmosphere, but no solid was formed.

[Example 3]
A mixed liquid consisting of 35 parts by weight of methyl methacrylate, 21 parts by weight of styrene, 14 parts by weight of methacrylic acid, 30 parts by weight of cyclohexanol, 50 ppm of 1,1-di (tert-butylperoxy) cyclohexane, and 1200 ppm of n-octyl mercaptan is prepared. Then, nitrogen gas was bubbled for 10 minutes. This mixture was continuously fed to a jacketed complete mixing reactor having an internal volume of 3 L at a rate of 1.5 L / hr for polymerization. When the reaction was conducted at a polymerization temperature of 135 ° C. for 2 hours, the polymer was completely dissolved, and the amount of polymer solids contained in the polymerization solution was 42% by mass. This polymerization solution is immediately passed through a heater, set to a barrel temperature of 255 ° C., and continuously supplied to a twin-screw extruder with a vent whose pressure is reduced to 25 Torr. Cyclic anhydride formation was performed. Unreacted monomers and solvent were recovered through a recovery line. The obtained polymer was passed through a vented twin screw extruder (L / D = 67) decompressed to 50 Torr, and unreacted monomers and the solvent were removed, and the production of a six-membered cyclic acid anhydride was completed. I let you. As a result of composition analysis of the obtained polymer, it was found that the methyl methacrylate unit was 43% by mass, the styrene unit was 33% by mass, the methacrylic acid unit was 7% by mass, and the 6-membered cyclic anhydride unit was 17% by mass. D1238; 230 ° C., 3.8 kg load) was 0.6 g / 10 min, Mw / Mn = 1.9, and Tg = 136 ° C.
The recovered unreacted monomer and solvent were heated to reflux at 90 ° C. for 3 hours in a nitrogen atmosphere, but no solid was formed.

[Comparative Example 1]
44 parts by weight of methyl methacrylate, 20 parts by weight of styrene, 16 parts by weight of methacrylic acid, 20 parts by weight of ethylbenzene (solubility parameter δ = 8.84), 50 ppm of 1,1-di (tert-butylperoxy) cyclohexane, n-octyl A liquid mixture consisting of 1500 ppm of mercaptan was prepared, and nitrogen gas was bubbled for 10 minutes. This mixture was continuously fed to a jacketed complete mixing reactor having an internal volume of 3 L at a rate of 1.5 L / hr for polymerization. When the polymerization temperature was 135 ° C., the solid content was deposited, so that it was impossible to dispense. As a result of composition analysis of the obtained solid content, methyl methacrylate unit 49 mass%, styrene unit 28 mass%, methacrylic acid unit 23 mass%, melt flow rate (ASTM-D1238; 230 ° C., 3.8 kg load) is 0. 0.1 g / 10 min and Mw / Mn = 2.4.
Moreover, the polymerization solution after removing the solid matter was supplied to a devolatilization tank set at 255 ° C. and 25 Torr to recover unreacted monomers and solvent. When the recovered liquid was heated at 90 ° C. for 3 hours under a nitrogen atmosphere, a solid substance was rapidly generated.

[Reference Example 1]
The copolymer of Example 1 was subjected to a Technobel T-die mounting extruder (KZW15TW-25MG-NH type / width 150 mm T-die mounting / lip thickness 0.5 mm) at a barrel temperature of 250 ° C., a T-die temperature of 250 ° C., and a resin temperature. An unstretched film having an average thickness of 100 μm was obtained by extrusion molding at 254 ° C. and a roll temperature of 130 ° C. The film moldability was good, and the total light transmittance was 92%.

[Reference Example 2]
The copolymer of Example 2 was subjected to a barrel temperature of 250 ° C., a T die temperature of 250 ° C., and a resin temperature using a Technobel T die mounting extruder (KZW15TW-25MG-NH type / width 150 mm T die mounting / lip thickness 0.5 mm). An unstretched film having an average thickness of 100 μm was obtained by extrusion molding at 254 ° C. and a roll temperature of 135 ° C. The film moldability was good, and the total light transmittance was 92%.

[Reference Example 3]
The copolymer of Example 2 was subjected to a barrel temperature of 250 ° C., a T die temperature of 250 ° C., and a resin temperature using a Technobel T die mounting extruder (KZW15TW-25MG-NH type / width 150 mm T die mounting / lip thickness 0.5 mm). An unstretched film having an average thickness of 100 μm was obtained by extrusion molding at 256 ° C. and a roll temperature of 135 ° C. The film moldability was good, and the total light transmittance was 92%.

[Reference Example 4]
Using Delpet 80N (Asahi Kasei Chemicals Co., Ltd .; Tg = 114 ° C.) with a Technobel T die mounting extruder (KZW15TW-25MG-NH type / width 150 mm T die mounting / lip thickness 0.5 mm), barrel temperature An unstretched film having an average thickness of 100 μm was obtained by extrusion molding at 250 ° C., a T die temperature of 250 ° C., a resin temperature of 254 ° C., and a roll temperature of 115 ° C. The film moldability was good, and the total light transmittance was 92%.
According to the method for producing a copolymer according to the present invention, it has high productivity such as high recyclability, and the copolymer obtained by the production method of the present invention and its molded product have heat resistance, optical properties, The process fluidity and mechanical properties can be highly balanced.

  The method for producing a copolymer according to the present invention has high productivity as compared with the prior art, such as good recyclability. The obtained copolymer has high transparency and high heat resistance, and is used for household goods, OA equipment, AV equipment, battery electrical equipment, lighting equipment, automotive parts use, housing use, liquid crystal display, plasma, etc. Light guide plate, diffuser plate, polarizing plate protective film, 1/4 wavelength plate, 1/2 wavelength plate, viewing angle control film, liquid crystal optical compensation used in displays such as displays, organic EL displays, field emission displays, rear projection televisions Retardation films such as films, display front plates, display substrates, lenses, touch panels, etc., and transparent substrates used in solar cells, optical communication systems, optical switching systems, optical measurement systems, waveguides, lenses, optical fibers , Fiber optic coating material, LED lens, lens cover It is suitably used for the etc..

Claims (13)

In the presence of the solvent (i) having a solubility parameter δ of 9.0 (cal / cm ³ ) ^1/2 or more and 15.0 (cal / cm ³ ) ^1/2 or less, an unsaturated carboxylic acid ester monomer (A ) And the unsaturated carboxylic acid monomer (B) to obtain a copolymer containing the unsaturated carboxylic acid ester monomer unit (a) and the unsaturated carboxylic acid monomer unit (b). A process for producing a copolymer, characterized in that   The method for producing a copolymer according to claim 1, wherein the solvent (a) contains at least one hydroxyl group in one molecule.   The method for producing a copolymer according to claim 1 or 2, wherein the solvent (a) has a boiling point (Y) of 100 ° C or higher.   The method for producing a copolymer according to any one of claims 1 to 3, wherein the solvent (a) contains an alcohol having a cyclic structure.   The method for producing a copolymer according to any one of claims 1 to 4, wherein the solvent (a) contains cyclohexanol. After the monomers (A) and (B) are copolymerized, the acid anhydride unit represented by the following general formula (1) is formed in the molecule by heat treatment at 180 to 300 ° C. and 200 Torr or less for 1 to 240 minutes. (C) is formed, The manufacturing method of the copolymer as described in any one of Claims 1-5 characterized by the above-mentioned.

However, R1 and R2 in the formula represent a hydrogen atom and an alkyl group having 1 to 6 carbon atoms, and R1 and R2 may be the same group or different groups.   The method for producing a copolymer according to claim 1, further comprising copolymerizing an aromatic group-containing vinyl monomer as a copolymerization component.   The method for producing a copolymer according to claim 7, wherein 1% by mass to 50% by mass of the aromatic group-containing vinyl monomer is used with respect to the mass of all monomers.   2. When the copolymer is polymerized, 5 to 60% by mass of the solvent (a) is present when the total of all monomers and the solvent (a) is 100% by mass. The manufacturing method of the copolymer as described in any one of -8.   Polymerization temperature is 50 degreeC or more and 200 degrees C or less, The manufacturing method of the copolymer as described in any one of Claims 1-9 characterized by the above-mentioned.   The copolymer obtained by the manufacturing method as described in any one of Claims 1-10.   The molded object which consists of a copolymer of Claim 11.   A film comprising the copolymer according to claim 11.