Polymer and production method thereof, molding material and molded product

Abstract

A molded product with excellent transparency can be obtained by using a polymer (D) obtained by suspension polymerization of a monomer mixture (1) containing (a) to (c) below: (a) 5-60 mass % of a specific macromonomer; (b) 5-60 mass % of the raw material monomer of a homopolymer (B) that has a solubility parameter that is different by 0.25 or more from the solubility parameter of the macromonomer (a); and (c) 10-80 mass % of the raw material monomer of a homopolymer (C) that has a solubility parameter that is different by less than 0.25 from the solubility parameter of macromonomer (a).

Claims

1. A polymer (D) obtained by suspension polymerization of a monomer mixture (1) comprising (a) to (c) below: (a) 15 to 60% by mass of a macromonomer represented by General Formula (1) ##STR00005## wherein: R and R.sup.1 to R.sup.n each independently represent a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, or a heterocyclic group, X.sub.1 to X.sub.n each independently represent a hydrogen atom or a methyl group, Z represents a terminal group, and n is a natural number of 2 to 10,000; (b) 5 to 60% by mass of a raw material monomer of a homopolymer (B) that is obtained by polymerization of the raw material monomer and has a solubility parameter which is different by 0.25 or more from the solubility parameter of the macromonomer (a); and (c) 10 to 80% by mass of a raw material monomer of a homopolymer (C) that is obtained by polymerization of the raw material monomer and has a solubility parameter which is different by less than 0.25 from the solubility parameter of the macromonomer (a), wherein a weight average molecular weight of the polymer (D) is 100,000 or more.

2. The polymer (D) according to claim 1, wherein the monomer for obtaining the macromonomer (a) is methacrylic acid ester, the raw material monomer (b) is acrylic acid ester, and the raw material monomer (c) is methacrylic acid ester.

3. The polymer (D) according to claim 1, wherein the raw material monomer (b) is acrylic acid ester having an ester group with 1 to 10 carbon atoms.

4. A molding material comprising the polymer (D) according to claim 1.

5. A molded product obtained from the molding material according to claim 4.

6. A method for producing a polymer (D) by suspension polymerization of the monomer mixture (1-I) comprising the following (a-I) to (c-I): (a-I) 15 to 60% by mass of a macromonomer represented by General Formula (1) ##STR00006## wherein: R and R.sup.1 to R.sup.n each independently represent a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, or a heterocyclic group, X.sub.1 to X.sub.n each independently represent a hydrogen atom or a methyl group, Z represents a terminal group, and n is a natural number of 2 to 10,000; (b-I) 5 to 60% by mass of acrylic acid ester; and (c-I) 10 to 80% by mass of methacrylic acid ester, wherein the macromonomer (a-I) comprises a methyl methacrylate unit and a methyl acrylate unit, the acrylic acid ester (b-I) is butyl acrylate, and the methacrylic acid ester (c-I) is methyl methacrylate.

7. A molding material comprising the polymer (D) that is obtained by the method according to claim 6.

8. A molded product obtained from the molding material according to claim 7.

9. A method for producing a polymer (D) by suspension polymerization of a syrup dispersion in which a monomer solution having the following macromonomer (a) dissolved in a monomer mixture (2), which contains the raw material monomer (b) and the raw material monomer (c) below, is dispersed in water: (a) 15 to 60% by mass of a macromonomer represented by General Formula (1) ##STR00007## wherein: R and R.sup.1 to R.sup.n each independently represent a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, or a heterocyclic group, X.sub.1 to X.sub.n each independently represent a hydrogen atom or a methyl group, Z represents a terminal group, and n is a natural number of 2 to 10,000; (b) 5 to 60% by mass of a raw material monomer of a homopolymer (B) that is obtained by polymerization of the raw material monomer and has a solubility parameter which is different by 0.25 or more from the solubility parameter of the macromonomer (a); and (c) 10 to 80% by mass of a raw material monomer of a homopolymer (C) that is obtained by polymerization of the raw material monomer and has a solubility parameter which is different by less than 0.25 from the solubility parameter of the macromonomer (a).

10. The method for producing a polymer (D) according to claim 9, wherein the syrup dispersion is obtained by dissolving the macromonomer (a) in the monomer mixture (2) containing the raw material monomer (b) and the raw material monomer (c), adding a radical polymerization initiator, and then adding a dispersion agent and a dispersion medium.

11. The method for producing a polymer (D) according to claim 9, wherein the syrup dispersion is obtained by adding the monomer mixture (2) containing the raw material monomer (b) and the raw material monomer (c) to an aqueous suspension containing particulate products of the macromonomer (a).

12. A molding material comprising the polymer (D) that is obtained by the method according to claim 9.

13. A molded product obtained from the molding material according to claim 12.

14. A polymer (D) obtained by suspension polymerization of a monomer mixture (1) comprising (a) to (c) below: (a) 15 to 60% by mass of a macromonomer represented by General Formula (1) below; ##STR00008## wherein: R and R.sup.1 to R.sup.n each independently represent a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, or a heterocyclic group, X.sub.1 to X.sub.n each independently represent a hydrogen atom or a methyl group, Z represents a terminal group, and n is a natural number of 2 to 10,000; (b) 5 to 60% by mass of a raw material monomer of a homopolymer (B) that is obtained by polymerization of the raw material monomer and has a solubility parameter which is different by 0.25 or more from the solubility parameter of the macromonomer (a), and (c) 10 to 80% by mass of a raw material monomer of a homopolymer (C) that is obtained by polymerization of the raw material monomer and has a solubility parameter which is different by less than 0.25 from the solubility parameter of the macromonomer (a), wherein the monomer for obtaining the macromonomer (a) is a monomer composition containing methacrylic acid ester and acrylic acid ester, the raw material monomer (b) is acrylic acid ester, and the raw material monomer (c) is methacrylic acid ester.

15. A molding material comprising the polymer (D) according to claim 14.

16. The polymer (D) according to claim 14, wherein the monomer for obtaining the macromonomer (a) is a monomer composition containing methyl methacrylate and methyl acrylate, the raw material monomer (b) is butyl acrylate, and the raw material monomer (c) is methyl methacrylate.

Description

EXAMPLES

(1) Hereinbelow, the present invention is described in view of Examples. Meanwhile, as described below, “parts” indicates “parts by mass”. Furthermore, weight average molecular weight (Mw), number average molecular weight (Mn), composition, structure, average particle diameter, and thermal decomposition temperature of a polymer, and haze and yellowness (YI) of a molded product were evaluated by the following methods.

(2) (Method for Evaluation of Polymer)

(3) (1) Mw and Mn

(4) The Mw and Mn were measured under the following conditions by using the gel permeation chromatography (GPC) (product name: HLC-8220, manufactured by TOSOH CORPORATION).

(5) Column: TSK GUARD COLUMN SUPER HZ-L (4.6×35 mm) and two TSK-GEL SUPER HZM-N (6.0×150 mm) were connected in series.

(6) Eluent: Chloroform

(7) Measurement temperature: 40° C.

(8) Flow rate: 0.6 mL/minute

(9) It should be noted that a calibration curve was prepared by using polymethyl methacrylate manufactured by Polymer Laboratories (four kinds of Mp (peak top molecular weight) 141,500, 55,600, 10,290 or 1,590), and the Mw and Mn were obtained by using the calibration curve.

(10) (2) Composition and Structure

(11) The polymer was dissolved in chloroform, and the composition and structure of the polymer were analyzed by .sup.1H-NMR measurement which uses a nuclear magnetic resonance apparatus (NMR) (product name: JNM-EX270 manufactured by JEOL Ltd.).

(12) (3) Average Particle Diameter

(13) Eight kinds of a sieve with a sieve opening of 3,300 μm, 2,000 μm, 1,000 μm, 500 μm, 300 μm, 212 μm, 106 μm or 63 μm were stacked in the order, that is, from a sieve with small sieve opening to a sieve with large sieve opening, on a tray dish to prepare a sieving apparatus.

(14) Subsequently, 20 g of a bead-like polymer was applied on top of the uppermost sieve. After operating the sieving apparatus for 10 minutes with vibration, the mass of the bead-like polymer remained on each sieve was measured and mass percentage was obtained for each sieve. Based on the mass percentage measured for each sieve, the particle size distribution curve of the polymer was prepared. The particle diameter at accumulation of 50% by mass was used as the average particle diameter of the polymer.

(15) (4) Thermal Decomposition Temperature

(16) The thermal decomposition temperature was measured on the basis of JIS K7120 by using Thermo Gravimetry Differential Thermal Analyzer (TG/DTA) (product name: TG/DTA 6300, manufactured by Seiko Instruments Inc.). The injection gas was nitrogen. Subsequently, by using the obtained thermo gravimetry value, a thermos gravimetric curve (TG curve) was established. From the established TG curve, the temperature corresponding to 5% mass reduction was designated as Td5 and the temperature corresponding to 10% mass reduction was designated as Td10.

(17) (Method for Evaluation of Molded Product)

(18) (1) Haze

(19) Haze of a molded product was measured on the basis of JIS K7136.

(20) (2) Yellowness (YI)

(21) YI of a molded product was measured on the basis of JIS K7105.

[Production Example 1] Synthesis of Dispersion Agent (1)

(22) To a reaction vessel (volume: 1200 L) equipped with a stirrer, a condenser, and a thermometer, 61.6 parts of 17% aqueous solution of potassium hydroxide, 19.1 parts of ACRYESTER M (product name, methyl methacrylate manufactured by Mitsubishi Rayon Co., Ltd.), and 19.3 parts of deionized water were added. Subsequently, the solution within the reaction vessel was stirred at room temperature, the exothermic peak was determined, and stirring was continued again for 4 hours. After that, the reaction solution within the reaction vessel was cooled to room temperature to obtain an aqueous solution of potassium methacrylate.

(23) Subsequently, to a reaction vessel (volume: 1050 L) equipped with a stirrer, a condenser, and a thermometer, 900 parts of deionized water, 60 parts of ACRYESTER SEM-Na (product name, sodium 2-sulfoethyl methacrylate, manufactured by Mitsubishi Rayon Co., Ltd., 42% by mass aqueous solution), 10 parts of the above aqueous solution of potassium methacrylate, and 12 parts of ACRYESTER M were added followed by stirring. The temperature was raised to 50° C. while flushing the inside of the polymerization apparatus with nitrogen. As a polymerization initiator, 0.08 part of V-50 (product name, 2,2′-azobis(2-methylpropionamidine)dihydrochloride acid salt manufactured by Wako Pure Chemical Industries, Ltd.) was added thereto and the temperature was raised again to 60° C. After raising the temperature, ACRYESTER M was continuously added dropwise for 75 minutes at a rate of 0.24 part/minute. After being maintained at 60° C. for 6 hours, the reaction solution was cooled to room temperature to obtain the dispersion agent (1) as a transparent aqueous solution with a solid content of 10% by mass.

[Production Example 2] Synthesis of Chain Transfer Agent (1)

(24) To an apparatus for synthesis equipped with a stirrer, 2.00 g (8.03 mmol) of cobalt (II) acetate tetrahydrate (manufactured by Wako Pure Chemical Industries, Ltd., Wako Special grade), 3.86 g (16.1 mmol) of diphenyl glyoxime (manufactured by Tokyo Chemical Industry Co., Ltd., EP grade), and 100 ml of diethyl ether from which oxygen has been removed in advance by nitrogen bubbling were added and stirred for 2 hours at room temperature.

(25) Subsequently, 20 ml of diethyl ether boron trifluoride complex (manufactured by Tokyo Chemical Industry Co., Ltd., EP grade) was added and stirred again for 6 hours. The resultant was filtered, and the solid was washed with diethyl ether and dried for 12 hours at 20° C., 100 MPa or less to obtain 5.02 g (7.93 mmol, yield 99% by mass) of the chain transfer agent (1) as a brown solid.

[Production Example 3] Synthesis of Macromonomer (a-1)

(26) To a polymerization apparatus equipped with a stirrer, a condenser, and a thermometer, 145 parts of deionized water, 0.13 part of sodium sulfate (Na.sub.2SO.sub.4), and 0.26 part of the dispersion agent (1) (solid content of 10% by mass) which has been prepared in Production Example 1 were added followed by stirring to obtain a homogenous aqueous solution. Next, 100 parts of ACRYESTER M, 0.0009 part of the chain transfer agent (1) which has been prepared in Production Example 2, and 0.1 part of PEROCTA O (product name, 1,1,3,3-tetramethylbutylperoxy2-ethylhexanoate manufactured by NOF CORPORATION) as a polymerization initiator were added to obtain an aqueous dispersion. Subsequently, the inside of the polymerization apparatus was fully flushed with nitrogen and the temperature of the aqueous dispersion was raised to 80° C. It was then maintained for 4 hours followed by raising the temperature to 92° C. at which the dispersion was maintained for 2 hours. After that, the reaction solution was cooled to 40° C. to obtain an aqueous suspension of the macromonomer. The aqueous suspension was filtered through a filter cloth, and the filtrate was washed with deionized water and dried for 16 hours at 40° C. to obtain the reactant. It was confirmed that the introduction rate of a terminal double bond in the reactant was close to 100% and the reactant is the macromonomer (a-1). The average particle diameter of the macromonomer (a-1) was 95 μm, Mw was 32,100, and Mn was 17,000. The evaluation results are shown in Table 1.

[Production Examples 4 to 6] Synthesis of Macromonomers (a-2) to (a-4)

(27) The macromonomers (a-2) to (a-4) were obtained in the same manner as the synthesis of macromonomer (a-1) except that the raw material monomer composition for obtaining the macromonomer (a-1) was the same as those shown in Table 1. The evaluation results are shown in Table 1.

[Production Example 7] Synthesis of Aqueous Suspension of Macromonomer (a-5)

(28) An aqueous suspension of the macromonomer (a-5) was synthesized in the same manner as Production Example 3. Furthermore, by using a part of the aqueous suspension of the macromonomer (a-5), the macromonomer (a-5) was obtained in the same manner as Production Example 3. The evaluation results are shown in Table 1.

(29) TABLE-US-00001 TABLE 1 Type Macromonomer (a) (a-1) (a-4) (a-2) (a-3) (a-4) (a-5) Composition of raw MMA 100 95 95 97 90 100 material monomer (part) MA — 5 5 3 10 — SP value (J/cm.sup.3).sup.0.5 19.40 19.50 19.50 19.46 19.59 19.40 Average particle diameter (μm) 95 100 100 99 105 148 Mw 32,100 56,000 56,000 42,000 106,000 31,300 Mn 17,000 26,800 26,800 19,200 52,000 16,500 Introduction rate of terminal About About About About About About double bond (%) 100 100 100 100 100 100 MMA: methyl methacrylate (product name: ACRYESTER M, manufactured by Mitsubishi Rayon Co., Ltd.) MA: methyl acrylate (Wako Special grade, manufactured by Wako Pure Chemical Industries, Ltd.)

Example 1

(30) By mixing 145 parts of deionized water, 0.13 part of sodium sulfate, and 0.26 part of the dispersion agent (1) which has been prepared in Production Example 1, an aqueous dispersion medium for suspension was prepared.

(31) To a separable flask with a condensing tube, 40 parts of the macromonomer (a-1), 36 parts of nBA (n-butyl acrylate manufactured by Mitsubishi Chemical Corporation) as the raw material monomer (b), and 24 parts of ACRYESTER M as the raw material monomer (c) were added and the temperature was raised to 50° C. under stirring to obtain a raw material syrup. After cooling the raw material syrup to 40° C. or lower, 0.5 part of V60 (product name, 2,2′-azobisbutyronitrile manufactured by Wako Pure Chemical Industries, Ltd.) was dissolved in the raw material syrup to obtain a syrup.

(32) In this case, solubility parameter (SP) of the macromonomer (a-1), SP of the homopolymer (B) obtained by polymerization of the raw material monomer (b), and SP of the homopolymer (C) obtained by polymerization of the raw material monomer (c) were described in Table 2.

(33) Subsequently, the above aqueous dispersion medium was added to this syrup and, by performing flushing of the atmosphere inside the separable flask with nitrogen by nitrogen bubbling and increasing the revolution number for stirring, a syrup suspension was obtained.

(34) The syrup dispersion was heated to 75° C. and the outside temperature of the separable flask was maintained till to have a polymerization exothermic peak. Once there is a polymerization exothermic peak, the syrup dispersion was heated to 85° C. when it reaches 75° C. By maintaining it for 30 minutes, the polymerization was completed and a suspension was obtained.

(35) After cooling the suspension to 40° C. or lower, the suspension was filtered through a filter cloth, and the filtrate was washed with deionized water and dried for 16 hours at 40° C. to obtain the polymer (D-1). It was found that Mw of the polymer (D-1) was 364,900 and the average particle diameter was 475 μm. Furthermore, the composition of the polymer (D-1) was MMA/nBA=64/36 (mass ratio), and the thermal decomposition temperature was as follows: Td5 was 237° C. and Td10 was 277° C.

(36) The polymer (D-1) was extruded at 220° C. by using a 30 mm monoaxial extruder to obtain the pellet-shaped molding material (1). By using the obtained molding material (1), injection molding was performed with an injection molding machine (product name: IS100EN, manufactured by Toshiba Machine Plastic Engineering Co., Ltd.) to obtain the molded product (1) which has width of 50 mm, length of 100 mm, and thickness of 2 mm. The molded product (1) had haze of 3.84% and YI of 2.10. The evaluation results are shown in Table 2.

(37) TABLE-US-00002 TABLE 2 Evaluation result Composition of the polymer (D) or (D′) Polymer Raw Raw Average Molded Macromonomer (a) material monomer (b) material monomer (c) particle product SP Amount SP Amount SP Amount diameter Td5 Td10 Haze YI Type Type value (part) Type value (part) Type value (part) Mw(−) (μm) (° C.) (° C.) (%) (−) Example 1 D-1 a-1 19.40 40 nBA 19.99 36 MMA 19.40 24 364,900 475 237 277 3.8 2 Example 2 D-2 a-1 19.40 20 nBA 19.99 40 MMA 19.40 40 427,400 390 257 311 10 3 Example 3 D-3 a-1 19.40 40 nBA 19.99 12 MMA 19.40 48 84,100 700 238 274 3.1 1 Example 4 D-4 a-1 19.40 40 nBA 19.99 18 MMA 19.40 42 377,000 760 227 265 4.3 3 Example 5 D-5 a-1 19.40 20 nBA 19.99 8 MMA 19.40 72 139,900 735 240 280 1.6 1 Example 6 D-6 a-2 19.50 40 nBA 19.99 30 MMA 19.40 30 278,000 720 278 310 2.1 3 Example 7 D-7 a-2 19.50 40 nBA 19.99 20 MMA 19.40 40 195,000 780 276 305 2.2 1 Example 8 D-8 a-2 19.50 40 nBA 19.99 12 MMA 19.40 48 128,000 700 281 306 1.2 1 Example 9 D-9 a-3 19.46 40 nBA 19.99 36 MMA 19.40 24 278,000 735 260 300 2.5 2 Example 10 D-10 a-3 19.46 40 nBA 19.99 24 MMA 19.40 36 180,000 690 274 302 1.5 1 Example 11 D-11 a-4 19.59 40 nBA 19.99 36 MMA 19.40 24 240,000 800 290 320 2.1 1 Example 12 D-12 a-5 19.40 40 nBA 19.99 36 MMA 19.40 24 1,573,100 693 228 271 2.7 3 Example 13 D-13 a-2 19.50 40 EHA 18.86 36 MMA 19.40 24 106,900 705 267 295 5.7 9 Example 14 D-14 a-2 19.50 40 EHA 18.86 12 MMA 19.40 48 1,055,400 690 276 293 1.5 1 Comparative D′-1 a-1 19.40 40 nBA 19.99 60 — — — Impossible 1,700 229 266 82 7 Example 1 to measure Comparative — a-1 19.40 70 nBA 19.99 15 MMA 19.40 15 Impossible to have suspension Example 2 polymerization Comparative D′-3 a-1 19.40 20 nBA 19.99 72 MMA 19.40 8 393,600 2,635 248 285 87 8 Example 3 Comparative — a-1 19.40 4 nBA 19.99 60 MMA 19.40 36 Impossible to have suspension Example 4 polymerization Comparative D′-5 a-1 19.40 10 nBA 19.99 40 MMA 19.40 50 394,300 750 214 285 70 3 Example 5 Comparative — a-1 19.40 40 EHA 18.86 60 — — — Impossible to have suspension Example 6 polymerization nBA: n-Butyl acrylate (manufactured by Mitsubishi Chemical Corporation) EHA: 2-Ethylhexyl acrylate (manufactured by Mitsubishi Chemical Corporation) MMA: Methyl methacrylate (manufactured by Mitsubishi Rayon Co., Ltd., product name: ACRYESTER M)

Example 2

(38) The polymer (D-2) was obtained in the same manner as Example 1 except that the composition of the polymer (D) was changed to the composition shown in Table 2. The results of evaluation of the polymer (D-2) are shown in Table 1.

(39) According to molding of the polymer (D-2) as a molding material at 210° C. by using a small injection molding machine (manufactured by Custom Scientific Instruments Inc., product name: CS-183-MMX), the molded product (2) having width of 10 mm, length of 20 mm, and thickness of 2 mm was obtained. The results of evaluation of the molded product (2) are shown in Table 2.

Examples 3 to 11

(40) The polymers (D-3) to (D-11) and the molded products (3) to (11) were obtained in the same manner as Example 2 except that the composition of the polymer (D) was changed to the composition shown in Table 2. The evaluation results are shown in Table 2.

Example 12

(41) 36 parts of nBA and 24 parts of ACRYESTER M were added to 98 parts of an aqueous suspension of the macromonomer (a-5) (40 parts in terms of the macromonomer (a-5)), and by keeping them at 50° C. for 1 hour under stirring, a raw material suspension was obtained. After that, the raw material suspension was cooled to 30° C., and 0.5 part of AIBN was added to the raw material suspension. Furthermore, an additional dispersion medium containing 220 parts of deionized water, 0.76 part of sodium sulfate, and 0.39 part of the dispersion agent (1) which has been prepared in Production Example 1 was added, and by performing flushing of the atmosphere inside the separable flask with nitrogen by nitrogen bubbling, a syrup suspension was obtained.

(42) The syrup dispersion was heated to 75° C. and the outside temperature of the separable flask was maintained till to have a polymerization exothermic peak. Once there is a polymerization exothermic peak, the syrup dispersion was heated to 85° C. when it reaches 75° C. By maintaining it for 30 minutes followed by cooling to 40° C. or lower, a suspension was obtained. The suspension was filtered through a filter cloth, and the filtrate was washed with deionized water and dried for 16 hours at 40° C. to obtain the polymer (D-12). The molded product (12) was obtained in the same manner as Example 2 except that the polymer (D-12) was used instead of the polymer (D-2). The evaluation results are shown in Table 2.

Examples 13 to 14

(43) The polymers (D-13) and (D-14) and the molded products (13) and (14) were obtained in the same manner as Example 2 except that the raw material monomer (b) was changed to 2-ethylhexyl acrylate (EHA). The evaluation results are shown in Table 2.

Comparative Example 1

(44) The polymer (D′-1) and the molded product (1′) were obtained in the same manner as Example 2 except that the composition of the polymer (D) was changed to the composition shown in Table 2. The evaluation results are shown in Table 2.

(45) Because the raw material monomer (c) was not used at the time of obtaining the polymer (D′-1), the obtained molded product (1′) exhibited white cloudiness.

Comparative Example 2

(46) It was tried to obtain the polymer (D′-2) in the same manner as Example 2 except that the composition of the polymer (D) was changed to the composition shown in Table 2. However, as the content of the macromonomer (a) was too high, a syrup suspension was not obtained so that it was impossible to perform suspension polymerization.

Comparative Example 3

(47) The polymer (D′-3) and the molded product (3′) were obtained in the same manner as Example 2 except that the composition of the polymer (D) was changed to the composition shown in Table 2. The evaluation results are shown in Table 2.

(48) Because the content of the macromonomer (b) was too high at the time of obtaining the polymer (D′-3), the obtained molded product (3′) exhibited white cloudiness.

Comparative Example 4

(49) It was tried to obtain the polymer (D′-4) in the same manner as Example 2 except that the composition of the polymer (D) was changed to the composition shown in Table 2. However, as the content of the macromonomer (a) was too low, the suspension was not evenly dispersed so that it was impossible to perform suspension polymerization.

Comparative Example 5

(50) The polymer (D′-5) was obtained in the same manner as Example 2 except that the composition of the polymer (D) was changed to the composition shown in Table 2. The evaluation results are shown in Table 2.

(51) Because the content of the macromonomer (a) was too low at the time of obtaining the polymer (D′-5), the obtained molded product (5′) exhibited white cloudiness.

Comparative Example 6

(52) It was tried to obtain the polymer (D′-6) in the same manner as Example 2 except that the composition of the polymer (D) was changed to the composition shown in Table 2. However, as the macromonomer (a) was not dissolved in the raw material monomer (b) so that it was impossible to perform suspension polymerization.