JP5026671B2 - Acrylic resin composition and vehicle member containing the composition - Google Patents

Description

  The present invention relates to an acrylic resin excellent in fluidity and chemical resistance, and a vehicle member including the composition.

  Acrylic resins generally have excellent transparency and weather resistance, and are therefore widely used for applications that require transparency and weather resistance such as vehicle lamp lenses. On the other hand, acrylic resins also have a problem that cracks are likely to occur due to chemicals contained in, for example, car wash detergents, window washer fluids, wax removers and the like.

  In order to improve this chemical resistance, a method using a high molecular weight acrylic resin (Patent Document 1), a method using an acrylic low molecular weight copolymer having a specific composition and molecular weight (Patent Document 2), etc. are proposed. Has been.

  However, in the method using the above-described high molecular weight acrylic resin, the fluidity tends to decrease. Further, in the method using the acrylic low molecular weight copolymer having the specific composition and molecular weight described above, there is a problem that heat resistance is lowered and cracks tend to be noticeable. Therefore, in any case, it cannot be said that the sufficient chemical resistance of the acrylic resin is exhibited.

Japanese Patent Laid-Open No. 3-108201 JP-A-4-277545

  The objective of this invention is providing the acrylic resin composition which can eliminate the trouble in the above-mentioned prior art, and the member for vehicles containing the same.

  Another object of the present invention is an acrylic resin composition having excellent chemical resistance, high fluidity and excellent moldability without substantially impairing transparency and weather resistance, which are inherent characteristics of an acrylic resin. And a vehicle member including the same.

As a result of intensive studies, the present inventors have found that each of them is a copolymer containing 95 to 99.9 parts by mass of methyl methacrylate units and 0.1 to 5 parts by mass of methyl acrylate units (the total amount is 100 parts by mass). Te, copolymer weight average molecular weight is from 150,000 to 250,000 (1), weight average molecular weight of at least saw contains a copolymer (2) which is 03,000 to 19,000, wherein the copolymerization According to the acrylic resin composition containing 75 to 85 parts by mass of the union (1) and 15 to 25 parts by mass (total amount of 100 parts by mass) of the copolymer (2) , the aforementioned problems are solved. I found out that I can do it.

  According to the present invention, an acrylic resin composition having excellent chemical resistance, high fluidity and excellent moldability without impairing transparency and weather resistance, which are inherent characteristics of an acrylic resin, and a vehicle including the same A member can be provided.

(Acrylic resin composition)
Each of the acrylic resin compositions of the present invention is a copolymer (containing 95 to 99.9 parts by mass of methyl methacrylate units and 0.1 to 5 parts by mass of methyl acrylate units (the total amount is 100 parts by mass)). 1) and a copolymer (2) at least. The former copolymer (1), the weight average molecular weight of from 150,000 to 250,000. On the other hand, the latter copolymer (2) has a mass average molecular weight of 30,000 to 199,000.

(Copolymer (1))
The copolymer (1) constituting the acrylic resin composition of the present invention is composed of 95 to 99.9 parts by mass of methyl methacrylate units and 0.1 to 5 parts by mass of methyl acrylate units (total amount is 100 parts by mass). ) comprises, having a weight average molecular weight of 1 50,000 to 250,000.

(Methyl methacrylate unit)
The content of methyl methacrylate units in this copolymer (1) is 95 to 99.9 parts by mass. By setting the methyl methacrylate unit to 95 parts by mass or more, an acrylic resin composition excellent in transparency and heat resistance can be obtained. It is preferable that the content rate of this methyl methacrylate unit is 98 mass parts or more.

  Moreover, the acrylic resin composition excellent in thermal stability can be obtained by making the content rate of the methyl methacrylate unit of a copolymer (1) 99.9 mass parts or less. The content of the methyl methacrylate unit is preferably 99 parts by mass or less.

  In the copolymer (1) used in the present invention, the content of methyl acrylate units is 0.1 to 5 parts by mass. By setting the methyl acrylate unit to 0.1 parts by mass or more, an acrylic resin composition having excellent thermal stability can be obtained. The content of the methyl acrylate unit is preferably 1 part by mass or more. Moreover, the acrylic resin composition excellent in heat resistance can be obtained by making the content rate of a methyl acrylate unit into 5 mass parts or less in a copolymer (1). The content of this methyl acrylate unit is preferably 2 parts by mass or less.

(Copolymerizable monomer unit)
The copolymer (1) constituting the acrylic resin composition of the present invention has a methyl methacrylate and a methyl acrylate in a range that does not impair the properties of the acrylic resin composition such as fluidity, chemical resistance, and heat resistance. A monomer unit other than the copolymerizable monomer unit can be contained.

(Mass average molecular weight)
The mass average molecular weight of the copolymer (1) constituting the acrylic resin composition of the present invention is 130,000 to 250,000. By setting the mass average molecular weight to 130,000 or more, an acrylic resin composition having excellent chemical resistance can be obtained. The mass average molecular weight of the copolymer (1) is preferably 150,000 or more. By setting the mass average molecular weight of the copolymer (1) to 250,000 or less, an acrylic resin composition having excellent fluidity can be obtained. The mass average molecular weight is preferably 200,000 or less.

(Content in acrylic resin composition)
Content of the copolymer constituting the acrylic resin composition of the present invention (1) has excellent from readily obtained point acrylic resin composition chemical resistance or heat resistance, der least 75 parts by weight Ri, it is favorable preferable is 8 0 parts by mass or more. Moreover, the content rate of a copolymer (1) is 85 mass parts or less from the point which obtains the acrylic resin composition excellent in fluidity | liquidity easily.

(Copolymer (2))
The copolymer (2) constituting the acrylic resin composition of the present invention is composed of 95 to 99.9 parts by mass of methyl methacrylate units and 0.1 to 5 parts by mass of methyl acrylate units (total amount is 100 parts by mass). ) And has a mass average molecular weight of 30,000 to 1.9 million.

(Methyl methacrylate unit content)
The content rate of the methyl methacrylate unit of the copolymer (2) which comprises the acrylic resin composition of this invention is 95-99.9 mass parts. By setting the methyl methacrylate unit to 95 parts by mass or more, an acrylic resin composition excellent in transparency and heat resistance can be obtained. It is preferable that the content rate of this methyl methacrylate unit is 98 mass parts or more. Moreover, the acrylic resin composition excellent in thermal stability can be obtained by making the content rate of the methyl methacrylate unit of a copolymer (2) into 99.9 mass parts or less. This content is preferably 99 parts by mass or less.

(Methyl acrylate unit content)
The content rate of the methyl acrylate unit of a copolymer (2) is 0.1-5 mass parts. By setting the methyl acrylate unit to 0.1 parts by mass or more, an acrylic resin composition having excellent thermal stability can be obtained. The content of methyl acrylate units is preferably 1 part by mass or more. Moreover, the acrylic resin composition excellent in heat resistance can be obtained by making the content rate of the methyl acrylate unit of a copolymer (2) into 5 mass parts or less. This content is preferably 2 parts by mass or less.

(Copolymerizable monomer unit)
The copolymer (2) constituting the acrylic resin composition of the present invention has a methyl methacrylate and a copolymer in a range that does not substantially impair the properties of the acrylic resin composition such as fluidity, chemical resistance, and heat resistance. Copolymerizable monomer units other than methyl acrylate can be contained.

(Mass average molecular weight)
The weight average molecular weight of the copolymer (2) constituting the acrylic resin composition of the present invention is from 30,000 to 199,000. By setting the mass average molecular weight to 30,000 or more, an acrylic resin composition having excellent heat resistance can be obtained. The mass average molecular weight is preferably 6,000 or more. Moreover, the acrylic resin composition excellent in fluidity | liquidity can be obtained by making the mass mean molecular weight of a copolymer (2) into 19000 or less. The mass average molecular weight of the copolymer (2) is preferably 15,000 or less.

Content of the copolymer constituting the acrylic resin composition of the present invention (2) is superior from readily obtained point acrylic resin composition liquidity, Ru der least 15 parts by weight. From the viewpoint of obtaining heat resistance or chemical resistance excellent acrylic resin composition, the content of the copolymer (2) is state, and are more than 25 parts by mass, not more than 2 0 parts by good Masui.

(Description of acrylic resin composition)
The deflection temperature under load of the acrylic resin composition of the present invention containing at least the copolymer (1) and the copolymer (2) is not particularly limited, but is preferably 95 ° C. or higher. By making the deflection temperature under load 95 ° C. or higher, it can be used for a vehicle member around the lamp. The deflection temperature under load is a measurement result according to JIS standard K7191-2, test condition A method.

(Production method)
The method for producing the acrylic resin composition of the present invention is not particularly limited. For example, the copolymer (1) and the copolymer (2) are separately polymerized by suspension polymerization, solution polymerization, bulk polymerization, or the like. A method and copolymer obtained by pre-mixing the produced and obtained copolymer with a known mixing device such as a Henschel mixer or a tumbler mixer, and then mixing with a single screw extruder or a twin screw extruder A method and a copolymer obtained by dissolving and polymerizing a copolymer (2) prepared in advance in a monomer mixture when producing (1) by a polymerization method such as suspension polymerization, solution polymerization or bulk polymerization (1) is produced by a polymerization method such as suspension polymerization, solution polymerization, bulk polymerization, etc., and then a method obtained by polymerizing copolymer (2) by additionally adding a monomer mixture or the like is used. Can do.

(Additive)
The acrylic resin composition of the present invention includes a plasticizer, an ultraviolet absorber, a light diffusing agent, a matting agent, a light stabilizer, an antioxidant, a lubricant, a release agent, an antistatic agent, and a colorant as necessary. Etc. can be contained. Such an additive is used when a copolymer (1) or a copolymer (2) is polymerized, or when the copolymer (1) and the copolymer (2) are mixed with a known mixing device such as a Henschel mixer or a tumbler mixer. Can be contained during premixing. The content of the additive other than the copolymer (1) or the copolymer (2) is 3 parts by mass or less (further 1) based on the acrylic resin composition of the present invention (100 parts by mass). It is preferable that it is below mass parts).

(Use)
The use of the acrylic resin composition of the present invention is not particularly limited. However, since the resin composition is excellent in transparency, fluidity and chemical resistance, it is suitable for a vehicle member, a sanitary member, a household appliance member and the like. It can be used. It is particularly suitable for a tail lamp cover, a head lamp cover, and a meter panel cover.

  Although the manufacturing method of the member for vehicles is not specifically limited, Heat melt molding methods, such as an injection molding method, a press molding method, an extrusion molding method, and a blow molding method, are mentioned. From the viewpoint of productivity, the injection molding method is preferable. Although it does not specifically limit as an injection molding method, As for injection molding temperature, the range of 200-270 degreeC is preferable.

  Next, the present invention will be specifically described by way of examples, but the present invention is not limited thereto. In each Example, each abbreviation shows the following compounds.

(component)
Abbreviation Compound name MMA: Methyl methacrylate MA: Methyl acrylate ST: Styrene

AIBN: 2,2′-azobis (isobutyronitrile)
n-OM: n-octyl mercaptan t-DM: t-dodecyl mercaptan S100A: glycerin monostearate (trade name: Riquemar S-100A, manufactured by Riken Vitamin Co., Ltd.)

  TvP: 2- (2H-benzotriazol-2-yl) -p-cresol (trade name: TINUVIN P, manufactured by Ciba-Gaiki Specialty Co., Ltd.)

(Physical property evaluation method)
Various physical property evaluation methods in Examples and Comparative Examples are as follows.

1. The composition ratio of the bead-shaped copolymer was determined from the difference between the amount of monomer charged during suspension polymerization and the residual amount of each monomer determined using gas chromatography. Measurement of the residual amount of each monomer was made by dissolving the bead copolymer in acetone, and then using a gas chromatography HP-6890 type manufactured by Hewlett-Packard Company. The separation column was HP-Wax (0.25 mm diameter × 30 m length). Measurement temperature 40 ° C., detector FID, and methyl isobutyl ketone as an internal standard substance.

2. It measured by the mass average molecular weight gel permeation chromatography method (GPC). The measurement of the gel permeation chromatography method was performed by dissolving a bead copolymer or pellet-shaped acrylic resin composition in tetrahydrofuran (THF), and then using a liquid chromatography HLC-8020 type manufactured by Tosoh Corporation. The separation column is TSK-Gel GMHXL in series, the solvent is THF (tetrahydrofuran), the flow rate is 1.0 ml / min, the detector is a differential refractometer, the measurement temperature is 40 ° C., the injection amount is 0.1 ml, and the standard polymer is polymethacrylic resin ( Shodex STANDARD M-75 manufactured by Showa Denko KK was used.

3. Copolymer composition ratio in the acrylic resin composition From the ratio of the peak areas of the copolymer (1) and the copolymer (2), using the results obtained by measuring the mass average molecular weight of the acrylic resin composition. Calculated.

4). A 100 × 35 × 2 mm test piece was cut out from the solvent-resistant pressure-formed plate, annealed at 80 ° C. for 20 hours, and then allowed to cool in a desiccator. The test piece was applied with ethanol to the test piece by the 1/4 ellipse test method, and the size of the cracks generated after 4 hours was evaluated according to the following criteria.
○: No crack of 15 mm or more in length.
Δ: There are 1 to 2 cracks having a length of 15 mm or more.
X: There are three or more cracks having a length of 15 mm or more.

5. A comparison was made in terms of the shear viscosity of the pellet-shaped acrylic resin compositions dried at 80 ° C for 24 hours. The shear viscosity was measured using a capillograph manufactured by Toyo Seiki Co., Ltd. under the conditions of capillary: L / D = 10/1 mm, temperature: 250 ° C., shear rate: 243.2 (Sec ⁻¹ ).

6). Deflection temperature under load It conformed to JIS standard K7191-2 and test condition A method.

7). Total light transmittance compliant with JIS standard K7361-1. Test piece thickness 3mm

8). Haze value compliant with JIS standard K7136. Test piece thickness 3mm

9. The yellowness of the test piece measured after the test and before the measurement was measured by the weather-resistant Sanshiya weather meter method under the following conditions. Sunshine Weather Meter uses WEL-SUN-DC type manufactured by Suga Test Instruments Co., Ltd., black panel temperature: 63 ° C, cycle: 12 minutes with rain / 48 minutes without rain, irradiation time: 3000 hours, test piece : Measured under conditions of a 3 mm thick flat plate. The yellowness was in accordance with JIS standard K7105 and colorimetric conditions (b).

10. Chemical resistance of vehicular lamps Apply ethanol (99 parts by mass pure) or wax remover CPC (manufactured by Yushiro Chemical Co., Ltd.) to the connecting part of the lamp cover and lamp body of the vehicular lamps at 55 ° C. The size of the crack generated at the connection between the lamp cover and the lamp body after heating for 4 hours was observed and evaluated according to the following criteria.

○: Crack size that can be confirmed with a magnifying glass but difficult to visually confirm ×: Crack size that can be visually confirmed

Production Example 1
A polymerization apparatus equipped with a stirrer (internal volume 2 liters) contains 58 parts by mass of 2-sulfoethyl sodium methacrylate, 31 parts by mass of aqueous potassium methacrylate (potassium methacrylate 30 parts by mass), and 11 parts by mass of methyl methacrylate. The monomer mixture and 900 parts by mass of deionized water were added and dissolved by stirring. Thereafter, the mixture was heated to 60 ° C. with stirring under a nitrogen atmosphere, and kept at 60 ° C. with stirring for 6 hours to obtain an aqueous anionic polymer compound solution. At this time, after the temperature reached 50 ° C., 0.1 part by mass of ammonium persulfate was added as a polymerization initiator, and 11 parts by mass of methyl methacrylate weighed separately was continuously added to the above reaction system over 75 minutes. It was dripped in.

Production Example 2
A monomer mixture containing 99 parts by mass of MMA and 1 part by mass of MA is charged with 0.1 part by mass of AIBN as a polymerization initiator and 0.12 parts by mass of n-OM as a chain transfer agent in a 20-liter container equipped with a stirrer. And mixed with stirring. In a 20 liter container equipped with another stirrer, 150 parts by mass of deionized water, 0.3 part by mass of the aqueous anionic polymer compound obtained in Production Example 1 as a dispersion stabilizer, and as a dispersion stabilization aid 0.35 part by mass of sodium sulfate was added and mixed with stirring.

  Each was put into a 40 liter polymerization vessel equipped with a stirrer, and after nitrogen substitution, the temperature was raised to 80 ° C. After completion of the polymerization exothermic peak, the mixture was kept at 95 ° C. for 30 minutes, and then cooled to 30 ° C. to complete the polymerization. Thereafter, washing and dehydration treatment and vacuum drying were performed to obtain a bead-shaped copolymer. The composition ratio and mass average molecular weight of the obtained bead copolymer were measured. The evaluation results are shown in Table 1.

Production Examples 3 to 16
A copolymer was produced in the same manner as in Production Example 2 except that the composition ratio or type of the monomer mixture, the amount of the polymerization initiator, and the chain transfer agent were changed. In addition, about what the polymerization exothermic peak was not seen, temperature rising started at 95 degreeC 4 hours after the temperature rising start at 80 degreeC. In Production Example 14, the beads were melted and fixed during vacuum drying. The composition ratio and mass average molecular weight of the obtained bead copolymer were measured. The evaluation results are shown in Table 1.

Comparative Example 9
85 parts by mass of the bead copolymer obtained in Production Example 2, 15 parts by mass of the bead copolymer obtained in Production Example 9, 0.2 part by mass of S100A as a release agent, and 0.05 part by mass of TvP as an ultraviolet absorber. After weighing and mixing with a Henschel mixer, a pellet-shaped acrylic resin composition was obtained using a PCM-30 twin screw extruder (temperature 250 ° C., with vacuum devolatilization). The copolymer composition ratio in the obtained pellet-like acrylic resin composition was measured. The results are shown in Table 2.

  Furthermore, total light transmittance, haze value, chemical resistance, fluidity, heat resistance, and weather resistance were evaluated using the obtained pellet-shaped acrylic resin composition. The results are collectively shown in Table 2.

Examples 2-7, Comparative Examples 1-6, Comparative Examples 9-11
A pellet-shaped acrylic resin composition was obtained in the same manner as in Comparative Example 9 except that the types or mixing ratios of the copolymer (1) and the copolymer (2) were changed as shown in Table 2. The copolymer composition ratio, transparency, haze value, chemical resistance, fluidity, heat resistance, and weather resistance in the obtained pellet-shaped acrylic resin composition were evaluated. The results are collectively shown in Table 2.

Comparative Example 7
A monomer mixture containing 60 parts by mass of MMA and 40 parts by mass of ST is charged with 0.35 parts by mass of AIBN as a polymerization initiator and 0.03 parts by mass of t-DM as a chain transfer agent in a 20-liter container equipped with a stirrer. And mixed with stirring.

  In a 20 liter container equipped with another stirrer, 150 parts by mass of deionized water, 0.3 part by mass of the aqueous anionic polymer compound obtained in Production Example 1 as a dispersion stabilizer, and as a dispersion stabilization aid 0.35 part by mass of sodium sulfate was added and mixed with stirring.

  Each of the two types of products obtained above was charged into a 40-liter polymerization vessel equipped with a stirrer, and after replacing with nitrogen, the temperature was raised to 87 ° C. After completion of the polymerization exothermic peak, the mixture was kept at 95 ° C. for 30 minutes, and then cooled to 30 ° C. to complete the polymerization. Thereafter, it was washed and dehydrated and dried to obtain a bead copolymer. The resulting bead copolymer had a compositional ratio of 60.2 mass% MMA units, 39.8 mass% ST units, and a mass average molecular weight of 151,000.

  100 parts by mass of the obtained bead copolymer, 0.2 part by mass of S100A as a release agent, 0.05 part by mass of TvP as an ultraviolet absorber were weighed and mixed with a Henschel mixer, and then a PCM-30 twin screw extruder (Temperature 250 ° C., with vacuum devolatilization) was used to obtain a pellet-shaped acrylic resin composition. Using the obtained pellet-shaped acrylic resin composition, the total light transmittance, haze, chemical resistance, fluidity, heat resistance, and weather resistance were evaluated. The results are collectively shown in Table 2.

Example 12
A monomer mixture containing 99 parts by mass of MMA and 1 part by mass of MA is charged with 0.1 parts by mass of AIBN as a polymerization initiator and 0.105 parts by mass of n-OM as a chain transfer agent in a 20-liter container equipped with a stirrer. And mixed with stirring.

  In a 20 liter container equipped with another stirrer, 150 parts by mass of deionized water, 0.3 part by mass of the aqueous anionic polymer compound obtained in Production Example 1 as a dispersion stabilizer, and as a dispersion stabilization aid 0.35 part by mass of sodium sulfate was added and mixed with stirring.

  Each of the two types of products obtained above was put into a polymerization vessel having an internal volume of 40 liters equipped with a stirrer, and the temperature was raised to 80 ° C. after substitution with nitrogen. After the end of the polymerization exothermic peak, the monomer mixture containing 17.5 parts by mass of MMA and 0.2 parts by mass of MA dissolved in a 10 liter container equipped with another stirrer was added 0.05 mass of AIBN as a polymerization initiator. As a chain transfer agent, 0.7 part by mass of n-OM was dropped into a polymerization vessel having an internal volume of 40 liters over 10 minutes. After dropping, the mixture was held at 80 ° C. for 4 hours and 90 ° C. for 30 minutes, and then cooled to 30 ° C. to complete the polymerization. Thereafter, it was washed and dehydrated and dried to obtain a bead copolymer.

  100 parts by mass of this bead copolymer, 0.2 part by mass of S100A as a release agent, and 0.05 part by mass of TvP as an ultraviolet absorber were weighed and mixed with a Henschel mixer, and then a PCM-30 twin screw extruder (temperature 250 A pellet-shaped acrylic resin composition was obtained using a vacuum devolatilization method. This obtained pellet-like acrylic resin composition contains a copolymer (1) having a weight average molecular weight of 180,000 and a copolymer (2) having a weight average molecular weight of 6,000. ) And the copolymer (2) had a composition ratio of 85/15. Using the obtained pellet-shaped acrylic resin composition, the total light transmittance, haze, chemical resistance, fluidity, heat resistance, and weather resistance were evaluated. The results are collectively shown in Table 2.

Comparative Example 8
A monomer mixture containing 99 parts by mass of MMA and 1 part by mass of MA is charged with 0.1 parts by mass of AIBN as a polymerization initiator and 0.105 parts by mass of n-OM as a chain transfer agent in a 20-liter container equipped with a stirrer. And mixed with stirring.

  In a 20 liter container equipped with another stirrer, 150 parts by mass of deionized water, 0.3 part by mass of the aqueous anionic polymer compound obtained in Production Example 1 as a dispersion stabilizer, and as a dispersion stabilization aid 0.35 part by mass of sodium sulfate was added and mixed with stirring.

  Each of the two types of products obtained above was put into a polymerization vessel having an internal volume of 40 liters equipped with a stirrer, and the temperature was raised to 80 ° C. after substitution with nitrogen. After the end of the polymerization exothermic peak, the monomer mixture containing 17.5 parts by mass of MMA and 0.2 parts by mass of MA dissolved in a 10 liter container equipped with another stirrer was added 0.05 mass of AIBN as a polymerization initiator. And 2.6 parts by mass of n-OM as a chain transfer agent were dropped into a polymerization vessel having an internal volume of 40 liters over 10 minutes. After dropping, the mixture was held at 80 ° C. for 4 hours and 90 ° C. for 30 minutes, and then cooled to 30 ° C. to complete the polymerization. Thereafter, it was washed and dehydrated and dried to obtain a bead copolymer.

  100 parts by mass of this bead copolymer, 0.2 part by mass of S100A as a release agent, and 0.05 part by mass of TvP as an ultraviolet absorber were weighed and mixed with a Henschel mixer, and then a PCM-30 twin screw extruder (temperature 250 A pellet-shaped acrylic resin composition was obtained using a vacuum devolatilization method. This obtained pellet-like acrylic resin composition contains a copolymer (1) having a weight average molecular weight of 180,000 and a copolymer (2) having a weight average molecular weight of 20,000. ) And the copolymer (2) were 84/16. Using the obtained pellet-shaped acrylic resin composition, the total light transmittance, haze, chemical resistance, fluidity, heat resistance, and weather resistance were evaluated. The results are collectively shown in Table 2.

Example 13
The lamp cover obtained by injection molding from the pellet-shaped acrylic resin composition obtained in Example 2 and the injection molding method from AS resin (trade name: Psycolac 3001M, manufactured by UMG-ABS Co., Ltd.) The lamp body thus obtained was used to obtain a vehicular lamp by a hot plate welding method at a normal temperature and a welding temperature of 400 ° C. A schematic cross-sectional view of this vehicular lamp is shown in FIG.

  Using this vehicular lamp, the chemical resistance of the vehicular lamp was evaluated. The results are shown in Table 3.

Examples 14 and 15 and Comparative Example 12
A vehicular lamp was obtained in the same manner as in Example 13 except that the acrylic resin composition that was the raw material of the lamp cover was changed as shown in Table 3. Using this vehicular lamp, the chemical resistance of the vehicular lamp was evaluated. The results are shown in Table 3.

  Since the acrylic resin composition of the present invention is a material having excellent chemical resistance, high fluidity and excellent moldability without impairing transparency and weather resistance, which are inherent characteristics of the acrylic resin, It is suitable for applications such as vehicle members that require chemical properties and moldability, and particularly suitable for tail lamp covers, head lamp covers, and meter panels.

It is the model top view (a) and schematic cross section (b) for demonstrating the "1/4 ellipse test method" used in the measurement of solvent resistance. It is a schematic cross section of the vehicular lamp produced in the example.

Explanation of symbols

1 Sample fixing belt 2 Chemical application surface

Claims (4)

Each 95-99.9 parts by weight of methyl methacrylate units, a copolymer comprising 0.1 to 5 parts by mass of methyl acrylate units (a total of 100 parts by mass), weight average molecular weight of 150,000 to 250,000 in certain copolymer (1), weight average molecular weight of at least saw contains a copolymer (2) which is 03,000 to 19,000, 75 to 85 weight the copolymer (1) Part, and an acrylic resin composition containing the copolymer (2) at a content of 15 to 25 parts by mass (total amount: 100 parts by mass) . The acrylic resin composition according to claim 1 , wherein the deflection temperature under load according to JIS standard K7191-2, test condition A method is 95 ° C or higher. Including at least a vehicle member acrylic resin composition according to claim 1 or 2. 4. The vehicle member according to claim 3 , wherein the vehicle member is in the form of a tail lamp cover, a head lamp cover, or a meter panel.

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