ACRYLIC FILM, METHOD FOR PRODUCING SAME, LAMINATE FILM, LAMINATED INJECTION MOLDED ARTICLE, AND METHOD FOR PRODUCING RUBBER-CONTAINING POLYMER

Abstract

An acrylic film having few fish eyes and a method for producing latex of an acrylic rubber-containing polymer having low amounts of coarse particles, excellent filtering properties, and low filter clogging frequency during a filtration step for removing foreign substances are provided. An acrylic film containing an acrylic rubber-containing polymer (G) has a thickness of 30 to 300 m, wherein the number of fish eyes that are 0.001 mm.sup.2 or greater in size is 130/m.sup.2 or fewer when a section having a light transmission rate of 75% or less for light having a wavelength of 400 to 1100 nm was detected as a fish eye.

Claims

1.-4. (canceled)

5. A method for producing an acrylic rubber-containing polymer (G) used for an acrylic film, the method comprising multi-stage polymerization steps including the following steps (1) and (2): (1) a first stage polymerization step in which a first emulsion having a monomer mixture (a) containing 20% by mass or more of alkyl acrylate emulsified in water is supplied to a polymerization vessel, and (2) a second stage polymerization step in which a second emulsion having a monomer mixture (b) containing 50% by mass or more of alkyl methacrylate emulsified in water is supplied to the polymerization vessel after the first polymerization step.

6. The method for producing an acrylic rubber-containing polymer (G) according to claim 5, wherein a polymerization step with at least one stage is included between the step (1) and the step (2).

7. The method for producing an acrylic rubber-containing polymer (G) according to claim 5, wherein a number average particle diameter of a dispersion phase is 300 m or less for the first emulsion and the second emulsion, respectively.

8.-14. (canceled)

Description

EXAMPLES

[0143] Hereinbelow, the present invention is described in greater detail in view of the examples. Meanwhile, parts and % in Examples and Comparative Examples indicate parts by mass and % by mass, respectively, and abbreviated symbols/abbreviations are as described in Table 1.

[0144] Furthermore, each measurement value of Examples was obtained by the method shown below.

[0145] [Evaluation 1] Particle diameter of dispersion phase of emulsion:

[0146] A single drop of emulsion was added on a preparative glass and the magnification ratio was fixed to a ratio at which at least ten dispersion phase particles can be observed in an observation range using an optical microscope. The number of every dispersion phase particles that can be observed in an observation range was counted, and an approximate particle size of each particle was obtained. Based on the obtained results, the number average dispersion particle diameter (m) of the dispersion phase was obtained.

[0147] [Evaluation 2] Mass average particle diameter of polymer particles:

[0148] A mass average particle diameter of the polymer particles was obtained by measuring the polymer latex, which has been obtained by emulsion polymerization, based on a dynamic light scattering method using a light scattering photometer (FPAR-1000) manufactured by Otsuka Electronics Co., Ltd.

[0149] [Evaluation 3] Filtering property of latex:

[0150] The polymer latex which has been obtained by emulsion polymerization was stirred well, and immediately thereafter, 100 g of the latex was weighed and filtered by using a tubular filtering device provided with nylon mesh having 270 mesh (mesh of 54 m) (KST-47 manufactured by ADVANTEC, effective filtering area of 12.5 cm.sup.2). Then, the amount of the latex (g) filtered for 30 seconds was measured. Expression was made in terms of that amount (g/30 seconds).

[0151] [Evaluation 4] Amount of acetone insolubles in acrylic film:

[0152] 1% by mass acetone solution containing 0.5 g of an acrylic film was prepared. After keeping it for 24 hours at room temperature (25 C.), centrifuge was performed at 16000 rpm for 90 minutes to remove the supernatant. The obtained wet product was dried at a reduced pressure (vacuum level of 47 mmHg) at room temperature for 18 hours. When the mass before extraction was Wi (g) and the mass of the dried product is Wd (g), W1 (%) calculated according to the following calculation formula was defined as an amount of acetone insolubles.

W1 (%)=Wd (g)/Wi (g)100.

[0153] [Evaluation 5] Analysis of components:

[0154] 1% by mass acetone solution containing 0.5 g of an acrylic film was prepared. After keeping it for 24 hours at room temperature (25 C.), centrifuge was performed at 16000 rpm for 90 minutes to remove the supernatant. The obtained wet product was dried at a reduced pressure (vacuum level of 47 mmHg) at room temperature for 18 hours, The dried residuals Wp (g) which have been obtained as described above were subjected to pyrolysis gas chromatography to measure the mass Wa (g) of the alkyl acrylate component. Wa/Wp100 was determined as the ratio (%) of the alkyl acrylate component in acetone insolubles. Further, acetone was evaporated from the aforementioned supernatant, and dried residuals We (g) which have been obtained after drying at a reduced pressure (vacuum level of 47 mmHg) at room temperature for 18 hours were subjected to pyrolysis gas chromatography to measure the mass Wm (g) of the alkyl methacrylate component. Wm/Wc100 was determined as the ratio (%) of the alkyl methacrylate component in acetone solubles.

[0155] [Evaluation 6] Number of fish eyes:

[0156] From a 1 m.sup.2 film having a thickness of 50 m, a length of 1 m, and a width of 1 m, the number of fish eyes with a size of 0.001 mm.sup.2 or greater to have a light transmission ratio of 75% or less for light having a wavelength of 400 to 1100 nm was measured by using B-LSC-6276-MR (manufactured by MEC Co., Ltd.).

Example 1

[0157] [1. Preparation of monomer mixture]

[0158] The compound of a type and an amount shown in Table 2 was injected to each vessel equipped with a stirrer followed by stirring to obtain a monomer mixture.

[0159] [2. Polymerization reaction]

[0160] To a vessel 1 containing the monomer mixture (a-1), 5.8 parts of deionized water and 0.7 part of a surfactant S were added followed by stirring to prepare the first emulsion (a-1e). Part of the emulsion was sampled and the particle diameter of the emulsion dispersion phase was measured and described in Table 3. Next, to a polymerization vessel equipped with a cooler, 147 parts of deionized water and 0.1 part of a surfactant S were added. After raising the temperature to 75 C., a mixture containing 5 parts of deionized water, 0.20 part of sodium formaldehyde sulfoxylate dehydrate, 0.0001 part of ferrous sulfate, and 0.0003 part of EDTA was added all at once to the polymerization vessel. Subsequently, the air inside the polymerization vessel was replaced with nitrogen, and while stirring the mixture under nitrogen atmosphere, the emulsion (a-1e) was added dropwise to the polymerization vessel for 9 minutes. After that, the reaction was additionally continued for 15 minutes to complete the polymerization. As a result, latex of the rubber polymer (A-1) was obtained.

[0161] Subsequently, the monomer mixture (c-1) in a vessel 2 was added dropwise to the aforementioned polymerization vessel for 90 minutes. After continuing the reaction for 60 minutes, latex of the polymer (A-1-c-1) was obtained. Furthermore, the monomer mixture (c-2) in a vessel 3 was added dropwise to the aforementioned polymerization vessel for 45 minutes. After continuing the reaction for 60 minutes, latex of the polymer (A-1-c2) was obtained.

[0162] Subsequently, to a vessel 4 containing the monomer mixture (b-1), 25 parts of deionized water and 0.3 part of a surfactant S were added followed by stirring to prepare the second emulsion (b-1e). Part of the emulsion was sampled and the particle diameter of the emulsion dispersion phase was measured and described in Table 3. It was then added dropwise to the aforementioned latex for 140 minutes. After continuing the reaction for 60 minutes, latex of the acrylic rubber-containing polymer (G-1) was obtained.

[0163] [3. Filtration of latex]

[0164] By using part of the acrylic rubber-containing polymer (G-1) in the latex, the mass average particle diameter of the polymer particles and the filtering property of the latex were measured, and the results are shown in Table 3. Furthermore, after filtering the latex by using a vibration type filtering device equipped with 270 mesh (average mesh: 54 m) made of SUS as a filtering medium, it was subjected to salting-out in an aqueous solution containing 3 parts of calcium acetate. After recovery with washing and drying, the rubber-containing polymer (G-1) was obtained in powder form.

[0165] [4. Production and evaluation of film]

[0166] 75 parts of the acrylic rubber-containing polymer (G-1) which has been obtained from above and 25 pars of the thermoplastic polymer (H-1) [MMA/MA copolymer (MMA/MA=99/1 (mass ratio), reduced viscosity sp/c=0.06 L/g)] were added with, as an additive, 1.4 parts of TINUVIN 234 manufactured by Ciba Specialty Chemicals Inc., 0.3 part of ADK STAB LA-67 manufactured by ADEKA CORPORATION, and 0.1 part of IRGANOX 1076 manufactured by BASF and admixed with each other by using a Henschell mixer. The mixture was supplied to a degassing type extruder (PCM-30 manufactured by Ikegai Corp.) which has been heated to 240 C. followed by kneading to obtain pellets of the resin composition (I-1). The resulting pellets were dried for 24 hours at 80 C. and, by using a 40 mm non-vent screw type extruder (L/D=26) equipped with a T die having a width of 300 mm, the film (F-1) with a thickness of 50 m was formed as a film at conditions including a cylinder temperature of 200 C. to 240 C., a T die temperature of 250 C., and a cooling roll temperature of 70 C. Then, the amount of acetone insolubles in the film, the ratio of the alkyl acrylate component in the acetone insolubles, the ratio of the alkyl methacrylate component in the acetone solubles, and the number of film fish eyes were measured and described in Table 3.

Example 2

[0167] Latex of the acrylic rubber-containing polymer (G-2) was obtained in the same manner as Example 1 except that a monomer mixture shown in Table 2 was used.

[0168] By using part of the acrylic rubber-containing polymer (G-2) in the latex, the mass average particle diameter of the polymer particles and the filtering property of the latex were measured, and the results are shown in Table 3.

[0169] Furthermore, after filtering the latex by using a vibration type filtering device equipped with 400 mesh (average mesh: 34 m) made of SUS as a filtering medium, it was subjected to salting-out in an aqueous solution containing 3 parts of calcium acetate. After recovery with washing and drying, the acrylic rubber-containing polymer (G-2) was obtained in powder form.

[0170] The film (F-2) with a thickness of 50 m was formed as a film in the same manner as Example 1 except that 100 parts of the aforementioned acrylic rubber-containing polymer (G-2) were used instead of 75 parts of the acrylic rubber-containing polymer (G-1) and 25 pars of the thermoplastic polymer (H-1). The resulting film was subjected to the same evaluation as Example 1 and the evaluation results shown in Table 3 were obtained. Since latex of the acrylic rubber-containing polymer (G-2) was filtered through a mesh with mesh size of 34 m, the number of fish eyes was low in the film.

Comparative Example 1

[0171] Latex of the acrylic rubber-containing polymer (G-1) was obtained in the same manner as Example 1 except that, as the monomer mixture (b-1), a monomer mixture in which 57 parts of MMA, 3 parts of MA, 0.248 part of n-OM, and 0.075 part of t-BHP were mixed was used and the monomer mixture was directly added dropwise to a polymerization vessel without being emulsified in water.

[0172] By using part of the acrylic rubber-containing polymer (G-1) in the latex, the mass average particle diameter of the polymer particles and the filtering property of the latex were measured, and the results are shown in Table 3. According to Comparative Example 1, the monomer mixture (b-1) was not prepared as an emulsion so that there are lots of coarse particles in latex, yielding a poor filtering property.

[0173] Furthermore, after filtering the latex by using a vibration type filtering device equipped with 270 mesh (average mesh: 54 m) made of SUS as a filtering medium, it was subjected to salting-out in an aqueous solution containing 3 parts of calcium acetate. After recovery with washing and drying, the acrylic rubber-containing polymer (G-1) was obtained in powder form.

[0174] Next, pellets of the resin composition (I-1) were obtained in the same manner as Example 1 except that the acrylic rubber-containing polymer (G-1) was used instead of the acrylic rubber-containing polymer (G-1). The pellets were dried at 80 C. for 24 hours and, according to the same method as Example 1, the film (F-1) with a thickness of 50 m was prepared as a film. The resulting film was subjected to the same evaluation as Example 1 and the evaluation results shown in Table 3 were obtained. Since the monomer mixture (b-1) was not supplied as an emulsion to the polymerization vessel, the number of fish eyes was high in the film.

Comparative Example 2

[0175] Latex of the acrylic rubber-containing polymer (G-2) was obtained in the same manner as Example 1 except that the monomer mixture (a-1) was directly added dropwise to a polymerization vessel without being emulsified in water.

[0176] By using part of the acrylic rubber-containing polymer (G-2) in the latex, the mass average particle diameter of the polymer particles and the filtering property of the latex were measured, and the results are shown in Table 3. According to Comparative Example 2, the monomer mixture (a-1) was not prepared as an emulsion so that the filtering property of latex was poor.

[0177] Furthermore, after filtering the latex by using a vibration type filtering device equipped with 270 mesh (average mesh: 54 m) made of SUS as a filtering medium, it was subjected to salting-out in an aqueous solution containing 3 parts of calcium acetate. After recovery with washing and drying, the acrylic rubber-containing polymer (G-2) was obtained in powder form.

[0178] Next, pellets of the resin composition (I-2) were obtained in the same manner as Example 1 except that the acrylic rubber-containing polymer (G-2) is used instead of the acrylic rubber-containing polymer (G-1). The pellets were dried at 80 C. for 24 hours and, according to the same method as Example 1, the film (F-2) with a thickness of 50 m was prepared as a film. The resulting film was subjected to the same evaluation as Example I and the evaluation results shown in Table 3 were obtained. Since the monomer mixture (a-2) was not prepared as an emulsion, the number of fish eyes was high in the film.

TABLE-US-00001 TABLE 1 Abbreviated symbols/abbreviation Compound name MMA Methyl methacrylate BA Butyl acrylate MA Methyl acrylate AMA Allyl methacrylate BDMA 1,3-Butylene glycol dimethacrylate t-BHP t-Butyl hydroperoxide CHP Cumene hydroperoxide n-OM n-Octyl mercaptan Surfactant S Sodium polyoxyethylene alkyl ether phosphate [product name: PHOSPHANOL RS-610NA, manufactured by TOHO Chemical Industry Co., Ltd.] EDTA Disodium ethylenediamine tetraacetate

TABLE-US-00002 TABLE 2 Comparative Comparative Example 1 Example 2 Example 1 Example 2 Monomer Compound Parts by Compound Parts by Compound Parts by Compound Parts by Vessel mixture name mass name mass name mass name mass Vessel 1 Monomer MMA 0.3 MMA 0.3 MMA 0.3 MMA 0.3 mixture BA 4.5 BA 4.5 BA 4.5 BA 4.5 (a-1) AMA 0.05 AMA 0.05 AMA 0.05 AMA 0.05 BDMA 0.2 BDMA 0.2 BDMA 0.2 BDMA 0.2 CHP 0.025 CHP 0.025 CHP 0.025 CHP 0.025 Vessel 2 Monomer MMA 9.6 MMA 9.6 MMA 9.6 MMA 9.6 mixture BA 14.4 BA 14.4 BA 14.4 BA 14.4 (c-1) AMA 0.25 AMA 0.25 AMA 0.25 AMA 0.25 BDMA 1 BDMA 1 BDMA 1 BDMA 1 CHP 0.016 CHP 0.016 CHP 0.016 CHP 0.016 Vessel 3 Monomer MMA 6 MMA 6 MMA 6 MMA 6 mixture MA 4 BA 4 MA 4 MA 4 (c-2) AMA 0.075 AMA 0.075 AMA 0.075 AMA 0.075 CHP 0.013 CHP 0.013 CHP 0.013 CHP 0.013 Vessel 4 Monomer MMA 57 MMA 55.2 MMA 57 MMA 57 mixture MA 3 BA 4.8 MA 3 MA 3 (b-1) n-OM 0.248 n-OM 0.22 n-OM 0.248 n-OM 0.248 t-BHP 0.075 t-BHP 0.075 t-BHP 0.075 t-BHP 0.075 Rubber-containing polymer G-1 G-2 G-1 G-2

TABLE-US-00003 TABLE 3 Comparative Comparative Example 1 Example 2 Example 1 Example 2 Monomer mixture (a-1) Emulsified Emulsified Emulsified Not emulsified Monomer mixture (b-1) Emulsified Emulsified Not emulsified Emulsified Mesh of filtering medium (m) 54 34 54 54 [Evaluation 1] Particle diameter of dispersion phase of first 50 45 50 emulsion (m) [Evaluation 1] Particle diameter of dispersion phase of second 80 85 75 emulsion (m) [Evaluation 2] Mass average particle diameter of polymer 123 120 125 122 particles (nm) [Evaluation 3] Filtering property of latex (g/30 seconds) 79 85 54 28 [Evaluation 4] Amount of acetone insolubles in acrylic film 50 58 53 52 (%) [Evaluation 5] Ratio of alkyl acrylate component in acetone 32 30 35 34 insolubles (%) [Evaluation 5] Ratio of alkyl methacrylate component in 94 90 91 95 acetone solubles (%) [Evaluation 6] Number of fish eyes (fish eye/m.sup.2) 125 83 233 1285

INDUSTRIAL APPLICABILITY

[0179] The laminated injection molded article including the acrylic film or the laminate film of the present invention can be applied for an automobile component, a construction material component, household goods, a home appliance component, an interior member, a ship member, a Personal Computer housing, an electronic communication device, or the like.