ACRYLIC RESIN FILM AND PRODUCTION METHOD THEREFOR

Abstract

A resin film comprising a multilayer structure acrylic polymer and the film having an acid value of not more than 0.018 mmol/g in an acetone insoluble matter, an acid value of not more than 0.012 mmol/g in an acetone soluble matter, a glass transition temperature of not less than 80 C. and a thickness of 5 to 300 pm is obtained by a method comprising emulsion polymerization for producing a latex comprising multilayer structure acrylic polymer, coagulating the latex comprising the multilayer structure acrylic polymer to obtain a slurry, washing and dehydrating the slurry, drying the dehydrated slurry to remove the multilayer structure acrylic polymer, mixing 0 to 35% by mass of an acrylic resin and 65 to 100% by mass of the removed multilayer structure acrylic polymer and subjecting the resultant mixture melted to an extrusion molding.

Claims

1. A resin film, comprising: a multilayer structure acrylic polymer, wherein the film has an acid value of not more than 0.018 mmol/g in an acetone insoluble matter, an acid value of not more than 0.012 mmol/g in an acetone soluble matter, a glass transition temperature of not less than 80 C., and a thickness of 5 to 300 m.

2. The resin film according to claim 1, wherein the multilayer structure acrylic polymer comprises a polymer (a), a polymer (b) and a polymer (c), the polymer (a) is a polymer composed of 40 to 98.99% by mass of a structural unit derived from methyl methacrylate, 1 to 60% by mass of a structural unit derived from an alkyl acrylate having a 1 to 8 carbon alkyl group, 0.01 to 1% by mass of a structural unit derived from a grafting agent, and 0 to 0.5% by mass of a structural unit derived from a crosslinking agent; the polymer (b) is a polymer composed of 70 to 99.5% by mass of a structural unit derived from an alkyl acrylate having a 1 to 8 carbon alkyl group, 0 to 30% by mass of a structural unit derived from methyl methacrylate, 0.5 to 5% by mass of a structural unit derived from a grafting agent, and 0 to 5% by mass of a structural unit derived from a crosslinking agent; and the polymer (c) is a polymer having a glass transition temperature of not less than 80 C. and composed of 80 to 99% by mass of a structural unit derived from methyl methacrylate, and 1 to 20% by mass of a structural unit derived from an alkyl acrylate having a 1 to 8 carbon alkyl group.

3. A method for producing the resin film according to claim 1, the method comprising: conducting emulsion polymerization to obtain a latex containing the multilayer structure acrylic polymer; coagulating the latex to obtain a slurry; washing and dewatering the slurry; drying the dewatered slurry to remove the multilayer structure acrylic polymer; and melting and extrusion molding a mixture of 0 to 35% by mass of an acrylic resin and 65 to 100% by mass of the removed multilayer structure acrylic polymer.

4. The method according to claim 3, further comprising: after the drying of the dewatered slurry to remove the multilayer structure acrylic polymer, feeding the removed multilayer structure acrylic polymer to an extruder to be pelletized; and drying the pelletized multilayer structure acrylic polymer to be used for producing the mixture.

5. A method for producing the resin film according to claim 2, the method comprising: polymerizing 40 to 98.99% by mass of methyl methacrylate, 1 to 60% by mass of an alkyl acrylate having a 1 to 8 carbon alkyl group, 0.01 to 1% by mass of a grafting agent and 0 to 0.5% by mass of a crosslinking agent in the presence of an emulsifying agent to obtain a latex (I) containing the polymer (a); polymerizing 70 to 99.5% by mass of an alkyl acrylate having a 1 to 8 carbon alkyl group, 0 to 30% by mass of methyl methacrylate, 0.5 to 5% by mass of a grafting agent and 0 to 5% by mass of a crosslinking agent in the presence of the latex (I) to obtain a latex (II) containing the polymer (a) and the polymer (b); polymerizing 80 to 99% by mass of methyl methacrylate and 1 to 20% by mass of an alkyl acrylate having a 1 to 8 carbon alkyl group in the presence of the latex (II) to obtain a latex (III) containing the polymer (a), the polymer (b) and the polymer (c); coagulating the latex (III) to obtain a slurry; washing and dewatering the slurry; drying the dewatered slurry to remove a multilayer structure acrylic polymer comprising the polymer (a), the polymer (b) and the polymer (c); and melting and extrusion molding a mixture of 0 to 35% by mass of an acrylic resin and 65 to 100% by mass of the removed multilayer structure acrylic polymer.

6. The method according to claim 5, further comprising: after the drying of the dewatered slurry to remove the multilayer structure acrylic polymer comprising the polymer (a), the polymer (b) and the polymer (c), feeding the removed multilayer structure acrylic polymer to an extruder to be pelletized; and drying the pelletized multilayer structure acrylic polymer to be used for producing the mixture.

7. The method according to claim 3, wherein the washing and dewatering of the slurry are performed at least twice by use of a screw decanter centrifuge.

8. The method according to claim 3, wherein the drying of the slurry is performed so that a moisture percentage is less than 0.1% by mass.

9. The method according to claim 3, wherein the washing and dewatering of the slurry are repeatedly performed so that the removed multilayer structure acrylic polymer has an acid value of not more than 0.008 mmol/g in an acetone insoluble matter and an acid value of not more than 0.012 mmol/g in an acetone soluble matter.

10. The method according to claim 3, wherein the extrusion molding is performed using an extruder with a residence time of not more than 5 minutes and a resin temperature of not higher than 280 C. in the extruder.

11. A layered product, comprising: at least one layer of the resin film according to claim 1, and at least one layer of a shaped product of another thermoplastic polymer.

12. The layered product according to claim 11, wherein the other thermoplastic polymer is at least one of polycarbonate polymers, vinyl chloride polymers, vinylidene fluoride polymers, vinyl acetate polymers, maleic acid copolymers, methacrylic resins, ABS resins, AES resins, and AS resins.

13. The method according to claim 4, wherein the drying of the pelletized multilayer structure acrylic polymer is performed so that a moisture percentage is less than 0.1% by mass.

Description

EXAMPLE 1

[0152] (Step 1)

[0153] In a reactor equipped with a stirrer, a thermometer, a nitrogen gas introduction part, a monomer introduction part and a reflux condenser, 150 parts of ion exchange water, 1.3 parts of sodium dodecyl benzene sulfonate and 0.05 part of sodium carbonate were charged, the inside of the reactor was sufficiently substituted with nitrogen gas and a state where an influence of oxygen is essentially null was formed. Thereafter, a temperature in the reactor was set to 80 C. Into the reactor, 0.015 part of potassium persulfate was charged, followed by stirring for 5 minutes. Then, a monomer mixture of 4 parts of MMA, 4 parts of nBA and 0.02 part of ALMA was dropped continuously over 20 minutes to perform an emulsion polymerization. After the end of the dropping, stirring was further performed for 30 minutes such that the conversion of the emulsion polymerization was not lower than 98% to obtain a latex containing a polymer (a).

[0154] In the reactor in which the latex containing the polymer (a) is present, 0.030 part of potassium persulfate was added, followed by stirring for 5 minutes. Then, a monomer mixture of 4 parts of MMA, 26 parts of nBA and 0.9 part of ALMA was continuously dropped over 40 minutes to perform a seed emulsion polymerization. After the end of the dropping, further followed by stirring for 30 minutes such that the conversion of the seed emulsion polymerization was not lower than 98% to obtain a latex containing the polymer (a) and a polymer (b).

[0155] In the reactor in which the latex containing the polymer (a) and the polymer (b) is present, 0.055 part of potassium persulfate was added, followed by stirring for 5 minutes. After that, a monomer mixture of 56 parts of MMA, 6 parts of nBA and 0.2 part of nOM was continuously dropped over 100 minutes to perform a seed emulsion polymerization. After the end of the dropping, further followed by stirring for 60 minutes such that the conversion of the seed emulsion polymerization was not lower than 98% to obtain a latex (hereinafter, referred to as latex (1)) containing the polymer (a), the polymer (b) and a polymer (c). An average particle size of the latex (1) determined by the light scattering method was 0.09 m. A monomer unit composition ratio and an average particle size of the latex (1) are shown in Table (1).

TABLE-US-00001 TABLE 1 Latex [Step1] [1] [2] [3] [4] [5] [6] Polymer(a) MMA [pts] 4 13 2.5 3 2.5 4 nBA [pts] 4 2 2.5 3 2.5 4 ALMA [pts] 0.02 0.03 0.015 0.015 0.01 0.015 Polymer(b) MMA [pts] 4 0 2 1.5 1.5 2 nBA [pts] 26 30 28 28.5 28.5 28 ALMA [pts] 0.9 0.6 0.9 0.5 0.45 0.6 Polymer(c) MMA [pts] 56 50 62 56 57 61 nBA [pts] 6 5 3 4 0 0 MA [pts] 0 0 0 4 8 4 nOM [pts] 0.2 0.15 0.25 0.2 0.24 0.22 Ave. Particle size [m] 0.09 0.09 0.09 0.09 0.09 0.09

[0156] (Step 2)

[0157] The latex (1) was frozen by leaving in an atmosphere of 20 C. for 4 hours. The obtained frozen product was added into triple volume of water of 80 C. to be thawed and obtain a slurry. The slurry was washed and dewatered by centrifugal force of 2100 G using a screw decanter centrifuge. Subsequently, ion exchange water was added to be a slurry concentration of 10%, followed by washing and dewatering again by the screw decanter centrifuge.

[0158] Thereafter, the dewatered slurry was dried with a continuous fluid-bed dryer set at 80 C. to obtain a core-shell multilayer structure acrylic polymer (hereinafter, expressed as acrylic polymer (A1)). The acrylic polymer (A1) was fed to a single screw extruder with a bent and pelletized under condition of bent vacuum pressure of 5 Torr, and a melt extruding temperature of 245 C. The residence time in the extruder was 2.5 minutes.

[0159] The pelletized acrylic polymer (A1) was dried at 80 C. The dried acrylic polymer (A1) had water percentage of 0.06% by mass, MFR of 2.0 g/10 minutes, Tg of 93 C., acid value of acetone insoluble matter of 0.004 mmol/g, and acid value of acetone soluble matter of 0.009 mmol/g. Characteristic values of the acrylic polymer (A1) and so on are shown in Table 2.

TABLE-US-00002 TABLE 2 Acrylic polymer [Step2] [A1] [A2] [A3] [A4] [A5] [A6] Latex [1] [1] [1] [2] [2] [2] Washing and dewatering Number of 2 2 1 2 3 2 washing/dewatering Pelletizing Condition Presence Yes Yes Yes Yes Yes Yes of Bent Extrusion 245 245 245 245 245 245 Temp. [ C.] Residence 2.5 2.5 2.5 2.5 2.5 2.5 Time[min.] Drying 80 80 80 80 Temp.[ C.] Resin Characteristics Moisture 0.06 0.16 0.06 0.06 0.06 0.3 Percentage[%] MFR[g/10 min] 2.0 1.8 2.0 1.8 1.8 1.8 Tg[ C.] 93 93 93 93 93 93 Acid Value 0.004 0.004 0.004 0.003 0.003 0.003 (insolubles) [mmol/g] Acid Value 0.009 0.009 0.010 0.009 0.008 0.009 (solubles) [mmol/g] Acrylic polymer [Step2] [A7] [A8] [A9] [A10] [A11] [A12] Latex [2] [3] [4] [5] [6] [6] Washing and dewatering Number of 2 2 2 2 2 2 washing/dewatering Pelletizing Condition Presence Yes Yes Yes Yes Yes Yes of Bent Extrusion 245 250 245 250 250 250 Temp. [ C.] Residence 2.5 2.5 2.5 2.5 2.5 2.5 Time[min.] Drying 80 80 80 80 Temp.[ C.] Resin Characteristics Moisture 0.15 0.05 0.05 0.05 0.05 0.05 Percentage[%] MFR[g/10 min] 1.8 2.3 1.8 2.2 2.1 2.1 Tg[ C.] 93 107 93 103 108 108 Acid Value 0.003 0.004 0.004 0.004 0.004 0.004 (insolubles) [mmol/g] Acid Value 0.009 0.008 0.007 0.006 0.007 0.006 (solubles) [mmol/g]

[0160] (Step 3)

[0161] 70 parts of the dried acrylic polymer (A1), 30 parts of the acrylic polymer (B1), and 2 parts of UV absorber (2,2-Methylenebis[6-(2H-benzotriazol-2-yl) -4-(1,1,3,3-tetramethylbutyl)phenol], Product Name: LA-31, manufactured by ADEKA Corporation) were mixed. The obtained mixture was fed to a single screw extruder with a bent and molten at 265 C. for residence time of 3.5 minutes, followed by extruding from a T die. The extruded film molten resin was wound on a mirrored roll to obtain a resin film having a thickness of 50 m. The obtained resin film had Tg of 100 C., acid value of acetone insoluble matter of 0.012 mmol/g, and acid value of acetone soluble matter of 0.008 mmol/g.

[0162] The resin film had haze at the room temperature of 0.4%, H.sup.80 of 2.4%, and H.sup.100 of 2.3%. It was found that the resin film was excellent in hot-water whitening resistance and boiling water whitening resistance. Results are shown in Table 3.

TABLE-US-00003 TABLE 3 Ex. [Step3] 1 2 3 4 5 6 7 8 composition ratio Acrylic 70 90 80 70 100 polymer[A1] [pts] Acrylic 90 polymer[A4] [pts] Acrylic 100 polymer[A5] [pts] Acrylic 100 polymer[A8] [pts] Acrylic 30 10 20 10 resin[B1] [pts] Acrylic 30 resin[B2] [pts] UV Absorber [pts] 2 2 2 2 2 2 2 Film Formation Condition Presence of Bent Yes Yes Yes Yes Yes Yes Yes Yes Film Formation 265 265 270 260 270 270 270 270 Temperature [ C.] Residence 3.5 3 3.5 3 4 5 4 3 Time [min.] Film Characteristics Film Thickness 50 55 50 60 50 50 50 50 [m] Tg [ C.] 100 96 98 102 93 96 93 105 Acid Value 0.012 0.013 0.012 0.011 0.013 0.013 0.012 0.012 (insolubles) [mmol/g] Acid Value 0.008 0.009 0.008 0.008 0.009 0.009 0.008 0.008 (solubles) [mmol/g] H.sub.0 [%] 0.4 0.4 0.4 0.4 0.4 0.4 0.3 0.4 H.sup.80 [%] 2.4 2.7 2.5 2.1 2.9 3.2 1.9 2.5 H.sup.100 [%] 2.3 2.5 2.7 2.2 3.5 3.9 2.2 3.1

EXAMPLE 2

[0163] A resin film was obtained in the same manner as in example 1 except that the amounts of the acrylic polymer (A1) and the acrylic resin (B1) in the step 3 were changed to 90 parts and 10 parts respectively, the residence time in the single screw extruder with the bent in the step 3 was changed to 3.0 minutes, and the film thickness was changed to 55 m. Characteristics of the obtained resin film are shown in Table 3.

EXAMPLE 3

[0164] A resin film was obtained in the same manner as in example 1 except that the amounts of the acrylic polymer (A1) and the acrylic resin (B1) in the step 3 were changed to 80 parts and 20 parts respectively, and the melting temperature in the single screw extruder with the bent in the step 3 was changed to 270 C. Characteristics of the obtained resin film are shown in Table 3.

EXAMPLE 4

[0165] A resin film was obtained in the same manner as in example 1 except that the acrylic resin (B1) in the step 3 was changed to the acrylic resin (B2), the melting temperature in the single screw extruder with the bent was changed to 260 C., the residence time was changed to 3.0 minutes, and the film thickness was changed to 60 pm in the step 3. Characteristics of the obtained resin film are shown in Table 3.

EXAMPLE 5

[0166] A resin film was obtained in the same manner as in example 1 except that the amounts of the acrylic polymer (A1) and the acrylic resin (B1) were changed to 100 parts and 0 part respectively, the melting temperature in the single screw extruder with the bent was changed to 270 C., and the residence time was changed to 4.0 minutes in the step 3. Characteristics of the obtained resin film are shown in Table 3.

EXAMPLE 6

[0167] A latex (2) was obtained in the same manner as in the step 1 of example 1 except that the monomer mixture in the step 1 was changed to that as shown in Table 1. An average particle size of the latex (2) determined by the light scattering method was 0.09 m.

[0168] A core-shell multilayer structure acrylic polymer (hereinafter, referred to as acrylic polymer (A4)) was obtained in the same manner as in the step 2 of example 1 except that the latex (2) was used in the place of the latex (1). Characteristics of the acrylic polymer (A4) are shown in Table 2.

[0169] A resin film was obtained in the same manner as in example 1 except that 70 parts of the acrylic polymer (A1) and 30 parts of the acrylic resin (B1) were changed to 90 parts of the acrylic polymer (A4) and 10 parts of the acrylic resin (B1), the melting temperature in the single screw extruder with the bent was changed to 270 C., and the residence time was changed to 5.0 minutes in the step 3. Characteristics of the obtained resin film are shown in Table 3.

EXAMPLE 7

[0170] A core-shell multilayer structure acrylic polymer (hereinafter referred to as acrylic polymer (A5)) was obtained in the same manner as in the step 2 of example 6 except that the number of washing and dewatering was changed to three times. Characteristics of the acrylic polymer (A5) are shown in Table 2.

[0171] A resin film was obtained in the same manner as in example 6 except that 90 parts of the acrylic polymer (A4) and 10 parts of the acrylic resin (B1) were changed to 100 parts of the acrylic polymer (A5), and the residence time in the single screw extruder with the bent in the step 3 was changed to 4.0 minutes. Characteristics of the obtained resin film are shown in Table 3.

EXAMPLE 8

[0172] A latex (3) was obtained in the same manner as in the step 1 of example 1 except that the monomer mixture in the step 1 of example 1 was changed to that shown in Table 1. An average particle size of the latex (3) determined by the light scattering method was 0.09 m.

[0173] A core-shell multilayer structure acrylic polymer (hereinafter, expressed as acrylic polymer (A8)) was obtained in the same manner as in the step 2 of example 1 except that the latex (3) was used in the place of the latex (1) and the melt extrusion temperature was changed to 250 C. Characteristics of the acrylic polymer (A8) are shown in Table 2.

[0174] A resin film was obtained in the same manner as in example 1 except that 70 parts of the acrylic polymer (A1), 30 parts of the acrylic resin (B1) and 2 parts of the UV absorber were changed to 100 parts of the acrylic polymer (A8), the melting temperature in the single screw extruder with the bent was changed to 270 C., and the residence time was changed to 3.0 minutes in the step 3. Characteristics of the obtained resin film are shown in Table 3.

EXAMPLE 9

[0175] A resin film was obtained in the same manner as in example 8 except that 100 parts of the acrylic polymer (A8) were changed to 70 parts of the acrylic polymer (A8) and 30 parts of the acrylic resin (B2), the melting temperature in the single screw extruder with the bent was changed to 265 C., and the residence time was changed to 2.5 minutes in the step 3. Characteristics of the obtained resin film are shown in Table 4.

TABLE-US-00004 TABLE 4 Ex. [Step3] 9 10 11 12 13 14 15 composition ratio Acrylic 100 polymer[A2] [pts] Acrylic 70 polymer[A8] [pts] Acrylic 100 polymer[A9] [pts] Acrylic 100 85 polymer[A10] [pts] Acrylic 88 polymer[A11] [pts] Acrylic 100 polymer[A12] [pts] Acrylic 30 15 12 resin[B2] [pts] UV Absorber [pts] 2 2 3 2 2 Film Formation Condition Presence of Bent Yes Yes Yes Yes Yes Yes Yes Film Formation 265 260 270 265 265 265 260 Temperature [ C.] Residence 2.5 2 3 3.5 3 3.5 2.5 Time [min.] Film Characteristics Film Thickness 50 50 50 50 50 50 50 [m] Tg [ C.] 108 93 98 103 108 110 108 Acid Value 0.012 0.011 0.011 0.010 0.011 0.011 0.012 (insolubles) [mmol/g] Acid Value 0.007 0.007 0.007 0.006 0.006 0.006 0.007 (solubles) [mmol/g] H.sub.0 [%] 0.4 0.4 0.4 0.4 0.4 0.4 0.4 H.sup.80 [%] 1.8 2.8 2.6 1.8 1.7 1.4 2 H.sup.100 [%] 2.1 3.3 3.0 2.2 2.0 1.9 2.5

EXAMPLE 10

[0176] A core-shell multilayer structure acrylic polymer (hereinafter, expressed as acrylic polymer (A2)) was obtained in the same manner as in the step 2 of example 1 except that the drying at 80 C. in the step 2 was not performed. Characteristics of the acrylic polymer (A2) are shown in Table 2.

[0177] A resin film was obtained in the same manner as in example 1 except that 70 parts of the acrylic polymer (A1) and 30 parts of the acrylic resin (B1) were changed to 100 parts of the acrylic polymer (A2), the melting temperature in the single screw extruder with the bent was changed to 260 C., and the residence time was changed to 2.0 minutes in the step 3. Characteristics of the obtained resin film are shown in Table 4.

EXAMPLE 11

[0178] A latex (4) was obtained in the same manner as in the step 1 of example 1 except that the monomer mixture in the step 1 of example 1 was changed to that shown in Table 1. An average particle size of the latex (4) determined by the light scattering method was 0.09 m.

[0179] A core-shell multilayer structure acrylic polymer (hereinafter, expressed as acrylic polymer (A9)) was obtained in the same manner as in the step 2 of example 1 except that the latex (4) was used in the place of the latex (1). Characteristics of the acrylic polymer (A9) are shown in Table 2.

[0180] A resin film was obtained in the same manner as in example 10 except that 100 parts of the acrylic polymer (A2) were changed to 100 parts of the acrylic polymer (A9), the melting temperature in the single screw extruder with the bent was changed to 270 C., and the residence time was changed to 3.0 minutes in the step 3. Characteristics of the obtained resin film are shown in Table 4.

EXAMPLE 12

[0181] A latex (5) was obtained in the same manner as in the step 1 of example 1 except that the monomer mixture in the step 1 of example 1 was changed to that shown in Table 1. An average particle size of the latex (5) determined by the light scattering method was 0.09 m.

[0182] A core-shell multilayer structure acrylic polymer (hereinafter, expressed as acrylic polymer (A10)) was obtained in the same manner as in the step 2 of example 1 except that the latex (5) was used in the place of the latex (1) and the melt extrusion temperature was changed to 250 C. Characteristics of the acrylic polymer (A10) are shown in Table 2.

[0183] A resin film was obtained in the same manner as in example 8 except that 100 parts of the acrylic polymer (A8) were changed to 100 parts of the acrylic polymer (A10), the melting temperature in the single screw extruder with the bent was changed to 265 C., and the residence time was changed to 3.5 minutes in the step 3. Characteristics of the obtained resin film are shown in Table 4.

EXAMPLE 13

[0184] A resin film was obtained in the same manner as in example 2 except that 90 parts of the acrylic polymer (A1), 10 parts of the acrylic resin (B1) and 2 parts of the UV absorber were changed to 85 parts of the acrylic polymer (A10), 15 parts of the acrylic resin (B2) and 3 parts of the UV absorber. Characteristics of the obtained resin film are shown in Table 4.

EXAMPLE 14

[0185] A latex (6) was obtained in the same manner as in the step 1 of example 1 except that the monomer mixture in the step 1 of example 1 was changed to that shown in Table 1. An average particle size of the latex (6) determined by the light scattering method was 0.09 m.

[0186] A core-shell multilayer structure acrylic polymer (hereinafter, expressed as acrylic polymer (A11)) was obtained in the same manner as in the step 2 of example 1 except that the latex (6) was used in the place of the latex (1) and the melt extrusion temperature was changed to 250 C. Characteristics of the acrylic polymer (A11) are shown in Table 2.

[0187] A resin film was obtained in the same manner as in example 1 except that 70 parts of the acrylic polymer (A1) and 30 parts of the acrylic resin (B1) were changed to 88 parts of the acrylic polymer (A11) and 12 parts of the acrylic resin (B2). Characteristics of the obtained resin film are shown in Table 4.

EXAMPLE 15

[0188] A core-shell multilayer structure acrylic polymer (hereinafter, expressed as acrylic polymer (A12)) was obtained in the same manner as in the step 2 of example 1 except that the latex (6) was used in the place of the latex (1), the melt extrusion temperature was changed to 250 C., and the drying at 80 C. was not performed. Characteristics of the acrylic polymer (A12) are shown in Table 2.

[0189] A resin film was obtained in the same manner as in example 10 except that 100 parts of the acrylic polymer (A2) were changed to 100 parts of the acrylic polymer (A12) and the residence time was changed to 2.5 minutes. Characteristics of the obtained resin film are shown in Table 4.

Comparative Example 1

[0190] A resin film was obtained in the same manner as in example 1 except that the residence time in the extruder in the step 3 of example 1 was changed to 18 minutes. Characteristics of the obtained resin film are shown in Table 5.

TABLE-US-00005 TABLE 5 Comp. Ex. [Step3] 1 2 3 4 5 6 composition ratio Acrylic 70 100 polymer[A1] [pts] Acrylic 100 polymer[A3] [pts] Acrylic 90 80 polymer[A6] [pts] Acrylic 90 polymer[A7] [pts] Acrylic 30 10 10 20 resin[B1] [pts] UV Absorber [pts] 2 2 2 2 Film Formation Condition Presence of Bent Yes Yes Yes Yes No Yes Film Formation 265 265 290 270 270 270 Temperature [ C.] Residence 18 6 4 10 18 5 Time [min.] Film Characteristics Film Thickness 50 50 45 50 50 50 [m] Tg [ C.] 100 93 93 96 96 96 Acid Value 0.022 0.019 0.021 0.024 0.025 0.023 (insolubles) [mmol/g] Acid Value 0.007 0.009 0.008 0.008 0.009 0.008 (solubles) [mmol/g] H.sub.0 [%] 0.4 0.5 0.4 0.4 0.4 0.4 H.sup.80 [%] 20.5 25.9 32 21.5 23.8 40.4 H.sup.100 [%] 41.5 58.0 55.3 49.2 54.2 60.5

Comparative Example 2

[0191] A core-shell multilayer structure acrylic polymer (hereinafter, expressed as acrylic polymer (A3)) was obtained in the same manner as in the step 2 of example 1 except that the number of the washing and dewatering in the step 2 was changed to one time. Characteristics of the acrylic polymer (A3) are shown in Table 2.

[0192] A resin film was obtained in the same manner as in example 1 except that 70 parts of the acrylic polymer (A1), 30 parts of the acrylic resin (B1) and 2 parts of the UV absorber were changed to 100 parts of the acrylic polymer (A3), and the residence time in the single screw extruder with the bent was changed to 6.0 minutes in the step 3. Characteristics of the obtained resin film are shown in Table 5.

Comparative Example 3

[0193] A resin film was obtained in the same manner as in example 1 except that 70 parts of the acrylic polymer (A1), 30 parts of the acrylic resin (B1) and 2 parts of the UV absorber were changed to 100 parts of the acrylic polymer (A1), the melting temperature in the single screw extruder with the bent was changed to 290 C., and the residence time was changed to 4.0 minutes in the step 3. Characteristics of the obtained resin film are shown in Table 5.

Comparative Example 4

[0194] A core-shell multilayer structure acrylic polymer (hereinafter, expressed as acrylic polymer (A6)) was obtained in the same manner as in the step 2 of example 6 except that the drying at 80 C. in the step 2 was not performed. Characteristics of the acrylic polymer (A6) are shown in Table 2.

[0195] A resin film was obtained in the same manner as in example 6 except that 90 parts of the acrylic polymer (A4) were changed to 90 parts of the acrylic polymer (A6), and the residence time in the single screw extruder with the bent was changed to 10.0 minutes in the step 3. Characteristics of the obtained resin film are shown in Table 5.

Comparative Example 5

[0196] A core-shell multilayer structure acrylic polymer (hereinafter, expressed as acrylic polymer (A7)) was obtained in the same manner as in the step 2 of example 6 except that the drying at 80 C. in the step 2 was changed to natural drying. Characteristics of the acrylic polymer (A7) are shown in Table 2.

[0197] A resin film was obtained in the same manner as in example 6 except that 90 parts of the acrylic polymer (A4) were changed to 90 parts of the acrylic polymer (A7), and the residence time in the single screw extruder with the bent was changed to 18.0 minutes in the step 3. Characteristics of the obtained resin film are shown in Table 5.

Comparative Example 6

[0198] A resin film was obtained in the same manner as in comparative example 4 except that, in the step 3 of comparative example 4, the amounts of the acrylic polymer (A6) and the acrylic resin (B1) were changed to 80 parts and 20 parts respectively, and the residence time in the extruder was changed to 5 minutes. Characteristics of the obtained resin film are shown in Table 5.