JP5237640B2 - Aromatic vinyl compound- (meth) acrylic acid copolymer resin-containing composition and method for producing the same - Google Patents

Description

  The present invention is an aromatic vinyl compound- (meth) acrylic acid copolymer resin-containing composition that is excellent in heat resistance, suppresses gelation due to an intermolecular condensation reaction, and does not contain a gel-like substance, and a method for producing the same About.

  The aromatic vinyl compound- (meth) acrylic acid copolymer resin is superior in heat resistance as compared with general polystyrene, and is mainly used as a material for food packaging materials for heating in a microwave oven. Specifically, after being formed into an extruded foam sheet or a biaxially stretched sheet, it is used after being shaped into a food container or a lid. Moreover, since it has an excellent balance between transparency and heat resistance, it is also suitable for a light diffusing resin plate containing a light diffusing agent, such as a lighting cover and a light diffusing plate for a transmissive display.

  As a disadvantage of the aromatic vinyl compound- (meth) acrylic acid copolymer resin, the heat history at the time of processing into a sheet or the like causes the carboxyl group in the polymer to undergo a condensation reaction between the polymer molecules, resulting in a gel-like substance. It has been pointed out that there is a case where a gel-like substance is generated by a similar reaction in the production process of a copolymer resin.

As an improvement measure, a method of adding a monohydroxyl compound in the production process of the copolymer (see Patent Document 1) and a composition containing the compound (see Patent Document 2) have been proposed. However, when these monohydroxyl compounds are used, there is a disadvantage that the gelation is not sufficiently suppressed particularly at a high temperature and under a high vacuum.
JP 56-161409 A JP 59-230043

  An object of the present invention is to provide an aromatic vinyl compound- (meth) acrylic acid copolymer resin-containing composition in which gelation at high temperature and high vacuum is suppressed and does not contain a gel-like substance, and a method for producing the same. It is an object.

In order to achieve the above object, the present invention has been intensively studied. As a result, the aromatic vinyl compound- (meth) acrylic acid copolymer resin-containing composition contains a specific amount of a specific polyoxyethylene alkyl ether. It was found that the gelation described above was remarkably suppressed by letting it squeeze. The present invention is based on such knowledge and has the following gist.
1. A composition mainly comprising a copolymer resin of an aromatic vinyl compound monomer and (meth) acrylic acid, and represented by the following general formula (1) with respect to the mass of the copolymer resin. An aromatic vinyl compound- (meth) acrylic acid copolymer resin-containing composition containing 0.05 to 0.5% by mass of polyoxyethylene alkyl ether.
R—O— (CH ₂ —CH ₂ —O) _X —H (1)
(R in the formula represents an alkyl group having 8 to 18 carbon atoms, X represents an integer representing the number of additions of ethylene oxide units, and the average number of additions is 1 to 15)
2. 2. The copolymer resin-containing composition according to 1 above, wherein the content of the (meth) acrylic acid unit in the copolymer resin is 3 to 15% by mass.
3. 3. The copolymer resin-containing composition according to 1 or 2 above, wherein the residual amount of the aromatic vinyl compound monomer in the copolymer resin-containing composition is 1000 ppm or less.
4). 4. The copolymer resin-containing composition according to any one of 1 to 3 above, which contains 0.05 to 0.5% by mass of an ultraviolet absorber.
5. 5. The copolymer resin-containing composition according to 4, wherein the ultraviolet absorber is 2- (2H-benzotriazol-2-yl) -4- (1,1,3,3-tetramethylbutyl) phenol.
6). 6. The copolymer resin-containing composition according to any one of 1 to 5 above, containing 0.05 to 0.5% by mass of a hindered amine light stabilizer.
7. 7. The copolymer resin-containing composition according to 6 above, wherein the hindered amine light stabilizer is bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate.
8). The resin board formed by extrusion molding or injection molding the copolymer resin containing composition of any one of the said Oki 1-7.
9. 8. A method for producing an aromatic vinyl compound- (meth) acrylic acid copolymer resin-containing composition according to any one of 1 to 7, wherein the aromatic vinyl compound monomer and (meth) acrylic An acid is copolymerized in a polymerization step, and then an unreacted product and / or a polymerization solvent is removed from a reaction product after the polymerization reaction in a devolatilization step, and an aromatic vinyl compound- (meth) acrylic acid copolymer is obtained. A method for producing a copolymer resin-containing composition comprising adding the polyoxyethylene alkyl ether represented by the general formula (1) before or during a devolatilization step of a process for producing a resin .
10 . 10. Said 9 which adds said polyoxyethylene alkyl ether so that content of said polyoxyethylene alkyl ether with respect to the mass of copolymer resin in the exit of the said polymerization process may be 0.05-0.5 mass%. A method for producing a copolymer resin-containing composition.

  According to the present invention, there is provided an aromatic vinyl compound- (meth) acrylic acid copolymer resin-containing composition that is capable of producing a molded article that is excellent in heat resistance and hardly contains a gel-like substance that significantly deteriorates the appearance. Furthermore, the aromatic vinyl compound-methacrylic acid copolymer resin-containing composition obtained by the present invention has a high gelation suppressing effect and can prevent the formation of a gel-like substance during molding.

The present invention is a composition comprising as a main component a copolymer resin of an aromatic vinyl compound monomer and (meth) acrylic acid (also referred to as a copolymer resin-containing composition in the present invention). And containing 0.05 to 0.5% by mass of polyoxyethylene alkyl ether represented by the following general formula (1) as an anti-gelling agent with respect to the mass of the copolymer resin. It is characterized by.
R—O— (CH ₂ —CH ₂ —O) _X —H (1)
(R in the formula represents an alkyl group having 8 to 18 carbon atoms, preferably 12 to 18 carbon atoms, and X is an integer representing the number of additions of ethylene oxide units, and the average number of additions is 1 to 15)

  The content of the polyoxyethylene alkyl ether represented by the general formula (1) used in the present invention is 0.05 to 0.5% by mass, preferably 0.8%, based on the mass of the copolymer resin. 1 to 0.4 mass%. Here, when the content of the polyoxyethylene alkyl ether is less than 0.05% by mass with respect to the mass of the copolymer resin, the gelation-inhibiting effect in the devolatilization step when the copolymer is produced is ineffective. It is sufficient and the effect of suppressing gelation during molding is insufficient. On the other hand, if the content of the polyoxyethylene alkyl ether exceeds 0.5% by mass with respect to the resin mass, the heat resistance is lowered, which is not preferable.

  The polyoxyethylene alkyl ether used in the present invention is generally synthesized by adding ethylene oxide to an alcohol having an alkyl group represented by R in the general formula (1). The polyoxyethylene alkyl ether thus obtained usually has a distribution in the number of added alkylene oxide units. In this invention, the average addition number of an ethylene oxide unit is 1-15, Preferably it is 4-12. Moreover, as long as the effect of the present invention is not impaired, propylene oxide may be added together with ethylene oxide within the range of the average number of additions of the present invention. When the average addition number of ethylene oxide units is less than 1, the content of alcohol not added with ethylene oxide increases, which is not preferable. When the average addition number of ethylene oxide units exceeds 15, the gelation suppressing effect is insufficient.

  Examples of the aromatic vinyl compound monomer used in the present invention include styrene, α-methyl styrene, o-methyl styrene, p-methyl styrene, or the like alone, and styrene is particularly preferable. The (meth) acrylic acid used in the present invention is acrylic acid or methacrylic acid. These may be used alone or in combination. In addition to these aromatic vinyl compound monomers, a copolymerizable monomer other than (meth) acrylic acid, for example, a monomer such as acrylonitrile, methacrylic acid ester, acrylic acid ester, etc. also has the effect of the present invention. If it is a grade which is not impaired, 1 type (s) or 2 or more types can be copolymerized.

  The content of the (meth) acrylic acid unit in the copolymer resin-containing composition of the present invention is preferably 3 to 15% by mass, more preferably 6 to 10% by mass. When the content of the (meth) acrylic acid unit is less than 3% by mass, the heat resistance is insufficient as a raw material for the microwave oven, and when it exceeds 15% by mass, the fluidity at the time of melting is remarkably lowered, and molding processing is performed. Sexuality deteriorates.

  The residual amount of the aromatic vinyl compound monomer in the copolymer resin-containing composition of the present invention is preferably 1000 ppm or less, more preferably 500 ppm or less. When the residual amount of the aromatic vinyl compound monomer exceeds 1000 ppm, the heat resistance of the resulting copolymer resin composition is lowered. Moreover, it is not preferable also from points, such as an odor.

In this invention, it is preferable that the weight average molecular weights of polystyrene conversion measured by the gel permeation chromatography method of an aromatic vinyl compound- (meth) acrylic acid type copolymer resin are 150,000 to 400,000. If it is less than 150,000, the strength of the molded product will be insufficient, and if it exceeds 400,000, the fluidity at the time of melting will decrease and the moldability will deteriorate. The weight average molecular weight (Mw) in the present invention can be measured using gel permeation chromatography (GPC), for example, under the following conditions.
GPC model: Shodex GPC-101 manufactured by Showa Denko
Column: Polymer Laboratories PLgel 10 μm MIXED-B
Mobile phase: Tetrahydrofuran Sample concentration: 0.2% by mass
Temperature: 40 ° C oven, 35 ° C inlet, 35 ° C detector
Detector: Differential refractometer The molecular weight of the aromatic vinyl compound- (meth) acrylic acid copolymer resin in the present invention is a value in terms of polystyrene, and the molecular weight at each elution time is calculated from the elution curve of monodisperse polystyrene. It is calculated as a converted molecular weight.

In the method for producing a copolymer resin-containing composition of the present invention, an aromatic vinyl compound monomer and (meth) acrylic acid are copolymerized in a polymerization step, and then a reaction after a polymerization reaction in a devolatilization step. Before or during the devolatilization step of the process for producing an aromatic vinyl compound- (meth) acrylic acid copolymer resin by removing unreacted substances and / or polymerization solvent from the product, polyoxyethylene alkyl It is preferred to add ether.
The addition of polyoxyethylene alkyl ether before the devolatilization step or in the devolatilization step means that the polyoxyethylene alkyl ether is added in any of the following steps (1) to (4). That is, (1) It adds to the monomer mixture of a raw material. (2) Add during the polymerization step. (3) Add to the polymerization solution after completion of the polymerization step. (4) When the devolatilization step is composed of two stages and the resin temperature of the first stage is lower than 200 ° C., it is added between the first and second stages. The addition amount is preferably added so that the content is 0.05 to 0.5% by mass with respect to the mass of the copolymer resin at the outlet of the final reactor. When the addition amount is less than 0.05% by mass, the effect of suppressing gelation is insufficient, and when the addition amount exceeds 0.5% by mass, the heat resistance is lowered, which is not preferable.

  Examples of the polymerization method that can be used in the method for producing the copolymer resin-containing composition of the present invention include known styrene polymerization methods such as a bulk polymerization method, a solution polymerization method, and a suspension polymerization method. Examples of the solvent include alkylbenzenes such as benzene, toluene, ethylbenzene, and xylene; ketones such as acetone and methyl ethyl ketone; and aliphatic hydrocarbons such as hexane and cyclohexane.

  In said polymerization method, a polymerization initiator and a chain transfer agent can be used as needed. As polymerization initiators, organic peroxides such as benzoyl peroxide, t-butylperoxybenzoate, 1,1-di (t-butylperoxy) cyclohexane, 1,1-bis (t-butylperoxy)- 3,3,5-trimethylcyclohexane, t-butylperoxyisopropyl carbonate, dicumyl peroxide, t-butylcumyl peroxide, t-butylperoxyacetate, t-butylperoxy-2-ethylhexanoate, 2 , 2-bis (4,4-di-t-butylperoxycyclohexyl) propane, polyether tetrakis (t-butylperoxycarbonate), ethyl-3,3-di (t-butylperoxy) butyrate, t- Examples include butyl peroxyisobutyrate. As the chain transfer agent, for example, aliphatic mercaptan, aromatic mercaptan, pentaphenylethane, α-methylstyrene dimer, terpinolene and the like can be used.

  In the copolymer resin-containing composition of the present invention, if necessary, rubber-reinforced components such as HI-PS resin and MBS resin, rubber-reinforced aromatic vinyl resins such as SBS, and aromatic vinyl-based thermoplastics such as SBS are used as necessary. An elastomer can be blended.

Various additives can be blended in the copolymer resin-containing composition of the present invention as necessary. The type of additive is not particularly limited as long as it is generally used for plastics, but it is antioxidant, flame retardant, lubricant, processing aid, anti-blocking agent, antistatic agent, antifogging agent, light resistance improvement. Agents, softeners, plasticizers, inorganic reinforcing agents, crosslinking agents, pigments, dyes, and the like, or mixtures thereof. For example, higher fatty acids such as stearic acid, zinc stearate, calcium stearate, magnesium stearate or salts thereof, lubricants such as ethylene bisstearyl amide, and plasticizers such as liquid paraffin may be included.
As the light resistance improver, a benzotriazole ultraviolet absorber or a hindered amine light stabilizer can be preferably used. As for content in the copolymer resin containing composition of light resistance improvement agents, such as a ultraviolet absorber and a light stabilizer, 0.05-0.5 mass% is respectively preferable, More preferably, it is 0.1-0.4. % By mass.

Hereinafter, the present invention will be described in more detail with reference to examples. In addition, the measuring method in the Example of this invention is shown below.
(1) Measurement of (meth) acrylic acid unit content 0.5 g of copolymer resin-containing composition was weighed and dissolved in a mixed solution of toluene / ethanol = 8/2 (volume ratio), and then potassium hydroxide was added in an amount of 0.8. Neutralization titration is performed with a 1 mol / L ethanol solution, the end point is detected, and the mass-based content of (meth) acrylic acid is calculated from the amount of potassium hydroxide ethanol solution used.
(2) Measurement of Vicat softening temperature It was determined according to JIS K-7206 at a heating rate of 50 ° C / hr and a test load of 50N.
(3) Measurement of residual styrene content 0.2 g of copolymer resin-containing composition was dissolved in 10 ml of dimethylformamide containing cyclopentanol as an internal standard substance, and gas chromatography FID-GC-12A manufactured by Shimadzu Corporation was used. It was measured. The column used was PEG-20MPT manufactured by GL Sciences, the detector used FID, and the carrier gas used nitrogen.
(4) Measurement of gelation inhibitor content 5 g of copolymer resin-containing composition is weighed and dissolved in THF. After dissolution, reprecipitate the polymer with methanol and a small amount of hydrochloric acid, and remove the reprecipitate by filtration. The filtrate was concentrated and finally 10 ml of methanol solution was concentrated, and the gelation inhibitor was quantified by high performance liquid chromatography (HPLC). In addition, fixed_quantity | quantitative_assay was performed by preparing three points | pieces of methanol solutions with known gelation inhibitor density | concentration, and creating a calibration curve.
HPLC model: Japan Waters alliance system 2695 separation module Detector: Differential refractometer (RI)
Column: Tosoh Corporation TSKgel ODS-120T 4.6 mm (ID) × 15 cm (L)
Mobile phase: 0.2% by mass of phosphoric acid added to methanol / water = 80/20 (volume ratio) Flow rate: 1.0 ml / min Column oven temperature: 40 ° C.
Detector temperature: 30 ° C
(5) Appearance of injection molded products (Gel generation status)
A flat plate (gate shape: 3 mm × 7 mm side gate) having a length of 75 mm, a width of 50 mm, and a thickness of 4 mm was molded at a temperature of 220 ° C. using the copolymer resin-containing composition. The number of flow traces of the gel-like substance appearing on the molded flat plate (which looks like streaks along the flow direction of the resin) was measured to confirm the occurrence of the gel. The case where a large amount (more than 25) of lines was confirmed in 5 plates was evaluated as xx, the case of 10-25 was evaluated as x, the case of 1-10 was evaluated as △, and the case where it was not confirmed was evaluated as ◯. . The gel substance can be confirmed by not dissolving in methyl ethyl ketone.
(6) Gelation degree (heat kneading test)
The copolymer resin-containing composition was heated and kneaded using the following plastic coder, and the gelation degree was evaluated by increasing the torque. Since water in the copolymer resin-containing composition affects the gelation reaction, it is necessary to perform a sufficient drying treatment before measurement. The test was performed under a nitrogen atmosphere at a set temperature of 300 ° C., a sample input amount of 47 g, a rotation speed of 50 rpm, and a kneading time of 25 minutes. The sample was dried at 100 ° C. for 4 hours. The ratio between the torque after 25 minutes and the minimum torque at the beginning of measurement (after about 6 minutes) was defined as the degree of gelation, and was used as a measure of the ease of gelation. If the degree of gelation is large, gelation tends to occur.
Apparatus: PLASTI-CORDER PL2000 manufactured by BRABENDER
Mixer type: W50E
(7) Light resistance A flat plate having a length of 40 mm, a width of 90 mm, and a thickness of 2 mm was prepared by injection molding, and an accelerated light resistance test was performed using a Xenon weatherometer Ci65A manufactured by ATLAS. Irradiation is performed for 500 hours under the conditions of an irradiation intensity of 0.35 W / m ² at a wavelength of 340 nm, a black panel temperature of 63 ° C., and a humidity of 50%, and the hue difference ΔE of the flat plate before and after the test is applied to Sigma 80 manufactured by Nippon Denshoku Industries Co. Measured. It was noted that there was no gel-like substance at the hue measurement location.

Example 1
A polymerization reactor was configured by connecting a first reactor, which is a complete mixing type stirring tank having an internal volume of 39 liters, and a second reactor, which is a complete mixing type stirring tank having an internal volume of 39 liters, in series. A mixed solution of 77.1% by mass of styrene, 5.9% by mass of methacrylic acid, and 17.0% by mass of ethylbenzene was prepared. This raw material solution was continuously supplied to the first reactor at a rate of 12.6 kg per hour, and each reactor was circulated in a full liquid state. In addition, at the 1st reactor inlet, with respect to the total amount of styrene and methacrylic acid in a raw material solution, 1,1-bis (t-butylperoxy) cyclohexane (Nippon Yushi Co., Ltd. perhexa C) is 250 ppm on a mass basis. Mixed. In addition, polyoxyethylene lauryl ether [P-1] is continuously added as a gelation inhibitor at the first reactor inlet, and polyoxyethylene lauryl ether with respect to the mass of the copolymer resin at the second reactor outlet. The content of [P-1] was set to 0.20% by mass.
In addition, as the polyoxyethylene lauryl ether [P-1] (the carbon number of the alkyl group R in the formula (1) is 12), Emulgen 109P manufactured by Kao Corporation was used. The reaction temperature of each reactor was adjusted to 130 ° C. in the first reactor and 140 ° C. in the second reactor.
Subsequently, the solution containing the copolymer resin continuously taken out from the second reactor was introduced into a vacuum devolatilization tank equipped with two stages in series and separated from unreacted monomers and ethylbenzene, and then in a strand form After being extruded and cooled, it was cut into pellets. In addition, about the vacuum devolatilization tank with a 1st stage preheater, the temperature of the preheater was set to 175 degreeC, the pressure of the vacuum devolatilization tank was set to 500 mmHg, and the jacket temperature of the vacuum devolatilization tank was set to 185 degreeC. About the vacuum devolatilization tank with a 2nd stage preheater, the temperature of the preheater was set to 240 degreeC, the pressure of the vacuum devolatilization tank was set to 8 mmHg, and the jacket temperature of the vacuum devolatilization tank was set to 240 degreeC. The resin temperature in the first-stage vacuum devolatilization tank was 168 ° C., and the resin temperature in the second-stage vacuum devolatilization tank was 231 ° C. Table 1 shows the characteristics of the copolymer resin composition of the pellets obtained.

Example 2
The procedure was the same as Example 1 except that the addition amount of the gelation inhibitor was 0.10% by mass.

Example 3
The procedure was the same as Example 1 except that polyoxyethylene lauryl ether [P-2] was used as the gelation inhibitor. The polyoxyethylene lauryl ether [P-2] used was Emulgen 104P manufactured by Kao Corporation (the carbon number of the alkyl group R in the formula (1) is 12).

Example 4
The procedure was the same as Example 1 except that polyoxyethylene C16-C18 alkyl ether [P-3] was used as the gelation inhibitor. In addition, the polyoxyethylene C16-C18 alkyl ether [P-3] used the Emulgen 210P by Kao Corporation (The carbon number of the alkyl group R in Formula (1) is 16-18).

Example 5
The procedure was the same as Example 1 except that polyoxyethylene lauryl ether [P-4] was used as the gelation inhibitor. In addition, the polyoxyethylene lauryl ether [P-4] used the Emulgen 120 by Kao Corporation (The carbon number of the alkyl group R in Formula (1) is 12).

Example 6
The same procedure as in Example 5 was performed except that the addition amount of the gelation inhibitor was 0.40% by mass.

Example 7
The procedure was the same as Example 1 except that polyoxyethylene polyoxypropylene alkyl ether [P-5] was used as the gelation inhibitor. In addition, polyoxyethylene polyoxypropylene alkyl ether [P-5] used Emulgen LS110 manufactured by Kao Corporation (the carbon number of the alkyl group R in the formula (1) is 12 to 15).

Comparative Example 1
The procedure was the same as Example 1 except that no gelation inhibitor was added.

Comparative Example 2
The same procedure as in Example 1 was performed except that octyl alcohol [A-1] was used as the gelation inhibitor and the addition amount was 2.0% by mass. The octyl alcohol [A-1] used was Calcole 0898 manufactured by Kao Corporation.

Comparative Example 3
The same procedure as in Example 1 was conducted except that stearyl alcohol [A-2] was used as a gelation inhibitor. As stearyl alcohol [A-2], Calcoal 8098 manufactured by Kao Corporation was used.

Comparative Example 4
It was the same as that of the comparative example 3 except the pressure of the vacuum devolatilization tank with a 2nd stage preheater having been 50 mmHg.

Comparative Example 5
The procedure was the same as Example 1 except that the addition amount of the gelation inhibitor was 0.02% by mass.

Comparative Example 6
The same procedure as in Example 1 was conducted except that the amount of the gelation inhibitor added was 0.70% by mass.

Comparative Example 7
The procedure was the same as Example 1 except that polyoxyethylene lauryl ether [P-6] was used as the gelation inhibitor. As polyoxyethylene lauryl ether [P-6], Emulgen 130K manufactured by Kao Corporation was used.

Example 8
To the copolymer resin-containing composition obtained in Example 1, TINUVIN 329 (2- (2H-benzotriazol-2-yl) -4- (1,1,1) manufactured by Ciba Specialty Chemicals Co., Ltd. was used as an ultraviolet absorber. 3,3-tetramethylbutyl) phenol) was added at 0.25 mass%, and extrusion blending was performed at 230 ° C. and 100 rpm in a 40 mmφ single-screw extruder to obtain a pellet-shaped copolymer resin-containing composition. .

Example 9
To the copolymer resin-containing composition obtained in Example 1, Sanol LS-770 (bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, manufactured by Sankyo Lifetech Co., Ltd.) as a hindered amine light stabilizer. ) Was added in an amount of 0.25% by mass, and extrusion blending was performed at 230 ° C. and 100 rpm with a 40 mmφ single-screw extruder to obtain a pellet-shaped copolymer resin-containing composition.

Example 10
To the copolymer resin-containing composition obtained in Example 1, TINUVIN 329 (2- (2H-benzotriazol-2-yl) -4- (1,1,1) manufactured by Ciba Specialty Chemicals Co., Ltd. was used as an ultraviolet absorber. 3,3-tetramethylbutyl) phenol) is added, and Sanol LS-770 (bis (2,2,6,6-tetramethyl-4-) produced by Sankyo Lifetech Co., Ltd. is used as a hindered amine light stabilizer. Piperidyl) sebacate) was added in an amount of 0.13% by mass, and extrusion blending was performed at 230 ° C. and 100 rpm in a 40 mmφ single-screw extruder to obtain a pellet-shaped copolymer resin-containing composition.

Example 11
To the copolymer resin-containing composition obtained in Example 1, TINUVIN 329 (2- (2H-benzotriazol-2-yl) -4- (1,1,1) manufactured by Ciba Specialty Chemicals Co., Ltd. was used as an ultraviolet absorber. 3,3-tetramethylbutyl) phenol) was added, and Sanol LS-770 (bis (2,2,6,6-tetramethyl-4-) produced by Sankyo Lifetech Co., Ltd. was used as a hindered amine light stabilizer. Piperidyl) sebacate) was added in an amount of 0.25% by mass, and extrusion blending was performed at 230 ° C. and 100 rpm using a 40 mmφ single screw extruder to obtain a pellet-shaped copolymer resin-containing composition.

Tables 1 and 2 show the results of the above-described Examples and Comparative Examples.
As is clear from the results in Table 1, the copolymer resin-containing composition of the present invention is excellent in Vicat softening temperature and appearance representing its heat resistance, and an increase in torque (degree of gelation) in a heat-kneading test. And is excellent in stability during heating and kneading. On the other hand, in Comparative Examples 1 to 3, Comparative Example 5 and Comparative Example 7, the effect of suppressing gelation is not sufficient, the appearance is poor due to gel generation, the increase in torque (degree of gelation) in the heating and kneading test is large, Easily gelled by kneading. About the comparative example 4 and the comparative example 6, although the gelatinization inhibitory effect is high, the Vicat softening temperature is low and it is inferior to heat resistance.

  Moreover, as is clear from the results in Table 2, the copolymer resin-containing composition of the present invention is excellent in light resistance. Furthermore, as shown in Examples 8 to 11, light resistance can be improved by blending an ultraviolet absorber and a hindered amine light stabilizer.

According to the present invention, it is possible to highly suppress gelation in the devolatilization process without impairing heat resistance, excellent stability during heat-kneading, and co-polymerization capable of suppressing gelation during molding processing. A coalesced resin-containing composition was obtained. The copolymer resin-containing composition is preferably used as a food packaging material for microwave oven heating, and preferably formed into an extruded foam sheet or a biaxially stretched sheet, and then used as an illumination cover, a light diffusing plate for a transmissive display, etc. As a light diffusing resin plate containing an appropriate light diffusing agent, it can be used after being shaped into a food container or a lid.

The entire contents of the specification, claims, and abstract of Japanese Patent Application No. 2005-271824 filed on September 20, 2005 are incorporated herein as the disclosure of the specification of the present invention. Is.

Claims (10)

A composition mainly comprising a copolymer resin of an aromatic vinyl compound monomer and (meth) acrylic acid, and represented by the following general formula (1) with respect to the mass of the copolymer resin. An aromatic vinyl compound- (meth) acrylic acid copolymer resin-containing composition containing 0.05 to 0.5% by mass of polyoxyethylene alkyl ether.
R—O— (CH ₂ —CH ₂ —O) _X —H (1)
(R in the formula represents an alkyl group having 8 to 18 carbon atoms, X represents an integer representing the number of additions of ethylene oxide units, and the average number of additions is 1 to 15)   Content of the (meth) acrylic acid unit in copolymer resin is 3-15 mass%, The copolymer resin containing composition of Claim 1 characterized by the above-mentioned.   The copolymer resin-containing composition according to claim 1 or 2, wherein the residual amount of the aromatic vinyl compound monomer in the copolymer resin-containing composition is 1000 ppm or less.   The copolymer resin-containing composition according to any one of claims 1 to 3, further comprising 0.05 to 0.5% by mass of an ultraviolet absorber.   The copolymer resin according to claim 4, wherein the ultraviolet absorber is 2- (2H-benzotriazol-2-yl) -4- (1,1,3,3-tetramethylbutyl) phenol. Containing composition.   The copolymer resin-containing composition according to any one of claims 1 to 5, comprising 0.05 to 0.5% by mass of a hindered amine light stabilizer.   The copolymer resin-containing composition according to claim 6, wherein the hindered amine light stabilizer is bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate.   The resin board formed by extrusion molding or injection molding the copolymer resin containing composition of any one of Claims 1-7.   A method for producing an aromatic vinyl compound- (meth) acrylic acid copolymer resin-containing composition according to any one of claims 1 to 7, comprising an aromatic vinyl compound monomer and (meth) Acrylic acid is copolymerized in the polymerization step, and then the unreacted product and / or polymerization solvent is removed from the reaction product after the polymerization reaction in the devolatilization step, and the aromatic vinyl compound- (meth) acrylic acid copolymer is recovered. Production of a copolymer resin-containing composition, wherein the polyoxyethylene alkyl ether represented by the general formula (1) is added before or in the devolatilization step of the process for producing a coalesced resin Method. As the content of the polyoxyethylene alkyl ether to the weight of the copolymer resin at the outlet of the polymerization step is 0.05 to 0.5 wt%, to claim 9, adding the polyoxyethylene alkyl ether The manufacturing method of the copolymer resin containing composition of description.