JPH01287161A - Acrylic resin composition for molded body excellent in matte property, molded product and production thereof - Google Patents

Abstract

PURPOSE:To obtain the subject composition, excellent in mass productivity, capable of providing molded products excellent in glare shielding and matte properties and solvent resistance without applying secondary heat processing and suitable as lighting covers, etc., by blending methyl methacrylate polymer with fine particles of a polymer having a specified particle diameter. CONSTITUTION:A composition obtained by blending (A) 100pts.wt. methyl methacrylate polymer with (B) 0.5-15pts.wt., preferably 2-10pts.wt. fine particles of a crosslinked methacrylic acid ester polymer having 1-50mum, preferably 1-30mum particle diameter and/or fine particles of a methacrylic acid ester polymer having a high polymerization degree (e.g. fine particles of crosslinked polymethyl methacrylate and/or fine particles of polymethyl methacrylate having a high polymerization degree). The resultant composition is injection molded into a cavity of a forming mold without any matte processing applied thereto.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to an acrylic resin composition with excellent matte properties, a molded article, and a method for producing the same, and more specifically, an acrylic resin composition with excellent matte properties, and a method for producing the same. The present invention relates to an acrylic resin composition, an acrylic resin molded article having an excellent matte surface obtained by injection molding the composition, and a method for producing the molded article.

(Prior art) Methyl methacrylate polymers are often used as plate-shaped or uneven-shaped products such as nameplates, instrument covers, displays, lighting covers, etc., and have recently developed matte surfaces to enhance luxury and anti-glare effects. Pre-use as acrylic resin molded products is becoming increasingly popular. Conventionally, in order to obtain an acrylic resin molded product with a matte surface, fine irregularities are provided on the surface of an extrusion roll or a mold such as molding, compression molding, injection molding, etc. to make it matte. ! Generally, the following two methods are used: kneading and extruding the ground powder, or applying a matte coating to the molded product after molding.

(Problems to be Solved by the Invention) However, in the case where the surface of a mold such as a roll or a mold is made matte by providing minute irregularities on the surface of the mold, the surface of the mold can be made matte. The surface of the mold has to be processed depending on the degree of oxidation, making it difficult to maintain a uniform matte state over a wide area, and press processing, vacuum processing, etc. When the secondary process is required, the fine irregularities on the surface disappear and the matte effect disappears, which is a problem that needs to be solved. As a technique for improving the disappearance of such a matte surface due to thermoforming, a matte plate (Japanese Patent Application Laid-open No. 14774-1983) in which inorganic fine powder is blended, kneaded and extruded is proposed.
8), but a large amount of inorganic fine powder is required to obtain a uniform and sufficient matte state, and as a result, the total light transmittance and
There is a drawback that a matte state with good translucency cannot be obtained because the parallel light transmittance is small.Furthermore, in the case of matte coating, a painting process is required in addition to the molding process. This method has problems such as not being able to coat a wide area or areas that are difficult to coat uniformly.

The present invention has been made in view of the problems that have not been solved in the past. The object of the present invention is to obtain an acrylic resin molded product having a matte surface with excellent anti-glare properties, solvent resistance, and mechanical strength without any surface processing.

(Means for Solving the Problem) The inventors of the present invention have developed polymer fine particles of a specific particle size as a result of extensive research into an injection molding method that has excellent mass productivity and does not require secondary heat processing. It was discovered that the problem described in item 1 could be solved by blending it into an acrylic resin, and the present invention was completed.

That is, according to the present invention, these objects are achieved by adding fine particles of crosslinked methacrylic ester polymer and/or highly polymerized Nisder methacrylate polymer having a particle size of 1 to 50 μm to 100 parts by weight of methyl methacrylate polymer. This is achieved by an acrylic resin composition for molded articles containing 05 to 15 parts by weight of fine particles and having excellent matte properties.

Moreover, the above objective can be achieved by an acrylic resin molded article having excellent matte properties, which is obtained by injection molding the above acrylic resin composition.

Furthermore, the above object is a method for obtaining an acrylic resin molded article by injection molding an acrylic 1!7j resin material, in which the acrylic resin composition is injected into a mold caddy which is not subjected to matte processing. This is achieved by a method for producing acrylic resin molded products with excellent matte properties.

(Function) The methyl methacrylate polymer of the present invention and 6. J, refers to a copolymer or pomopolymer containing 80% or more of medyl methacrylate, an ultraviolet absorber, a heat stabilizer, a coloring agent,
There is no problem with the inclusion of trace additives such as fillers. The molecular weight is not particularly limited in the present invention, but is generally 50,000 to 500,000, preferably 70,000, from the viewpoint of ease of kneading during injection molding, physical properties, etc. 300,000 to 300,000.

The crosslinked methacrylic acid ester polymer fine particles and/or the highly polymerized Nisdel methacrylate polymer particles used in the present invention are Iii copolymerizable with methacrylic acid ester or Nisdel methacrylate containing methacrylic acid ester as the main monomer component. Bulk polymerization of polymer mixture and crosslinking agent, r
Fine powder obtained by loom-pulverizing or fine particles obtained by suspension polymerization, Nisder methacrylate or a monomer mixture copolymerizable with methacrylic ester whose main monomer component is Nisder methacrylate or methacrylic ester. Degree of polymerization 500
0 or more, preferably 8,000 or more, refers to fine powder obtained by loom-pulverizing a product that has been subjected to bulk polymerization or mixed polymerization, or fine particles obtained by suspension polymerization, or fine particles obtained by mixing these.

The methacrylic esters used in the present invention include straight chain aliphatic esters such as methyl methacrylate, octyl methacrylate, and stearyl methacrylate; branched aliphatic esters such as ter-butyl methacrylate and 2-ethylhexyl methacrylate; These include unsaturated esters such as allyl methacrylate, preferably linear aliphatic esters such as methyl methacrylate and stearyl methacrylate, and most preferably methyl methacrylate. Examples of monomers that can be copolymerized with methacrylic esters include (meth)acrylic acid alkyl esters other than the methacrylic ester as the main component ((meth)acrylic acid alkyl esters refer to acrylic acid alkyl esters, and methacrylic acid alkyl esters. ), (meth)acrylic acid hydroxyalkyl ester, (meth)acrylic acid, (meth)acrylonitrile, sutyrene, α-
Examples include medylstyrene and maleic anhydride. The crosslinking agent is not particularly limited, but it is preferable to use a crosslinking agent having two or more unsaturated groups, such as difunctional crosslinking agents such as ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, and neopentyl glycol dimethacrylate. Dimethacrylate, divinylbenzene, etc. are preferably used, and the proportion of 1 to 5
It is used in an amount of 0% by weight, preferably 5 to 50% by weight. These fine particles produced by suspension polymerization are disclosed in Japanese Patent Application Laid-open No. 4
8-49838, Japanese Patent Application No. 62-307238, etc., or a commercially available product manufactured by Matsumoto Yushi Pharmaceutical Co., Ltd.: Matsumoto Microsphere-M2O3 (cross-linked polyester). Methyl methacrylate spherical fine particles), Sekisui Plastics Co., Ltd.: Tekuborimer MB (polymethyl methacrylate micro spherical particles: high degree of polymerization type), MBX (cross-linked polymethyl methacrylate-1 to micro spherical particles), etc. can be used. . The particle size of the fine particles used in the present invention is 1 to 5.
0 μm, preferably 1 to 30 μm, and the average particle diameter is 3 to 25 μfn, preferably 4 to 15 μm. More preferred embodiments of the fine particles include stability of matte appearance and matte surface against fluctuations in polymer fine particle content. From the viewpoint of uniformity, the particle size is 1 to 30 μm, preferably 1 to 20 μm.
In the weight distribution, ungrooved particles within the range of 10 μrn and a particle size of 10 μrn account for 70% or more, preferably 90% or more. The average particle size here means the particle size that accounts for 50% of the total weight by integrating each particle size by weight.
A5000), etc. Spherical fine particles produced by suspension polymerization are preferably used from the viewpoint of uniformity of matte state and texture, and narrower particle size distribution is more preferably used because uniform matteness can be obtained. When the average particle size of the polymer fine particles exceeds 50 μm or when the average particle size is 25 μm
If it exceeds this value, the surface will not become fine and uniformly matte, which is undesirable. The blending amount varies depending on the intended use, but in order to obtain good anti-glare properties, 0.5~
It is necessary to incorporate 15 parts by weight, preferably 2 to 10 parts by weight, per 100 parts by weight of the methyl methacrylate polymer.

If the amount is less than 0.5 parts by weight, the level of gloss that makes the surface sufficiently matte increases and the beauty is lost, while if it exceeds 15 parts, the surface is uniformly matted, but It does not have a particularly favorable effect on performance. In addition, if the fine particles are not cross-linked and have a degree of polymerization of less than 5000, the particles during injection molding may dissolve in the base resin and a matte state may not be developed or may be extremely insufficient, which is undesirable. .

In the present invention, the acrylic resin composition for molded objects with excellent matting properties refers to the crosslinked methacrylate ester polymer fine particles having a particle size of 1 to 50 μm based on 100 parts by weight of the methyl methacrylate polymer and/or Or it contains 0.5 to 15 parts by weight of highly polymerized methacrylic acid ester polymer particles, for example, a methyl methacrylate polymer and the above particles are mixed by stirring in a Henshilmi Azer or the like, or after mixing, the mixture is extruded into an extrusion molding machine. It is said to be made into pellets. The composition may be used in order to store it stably or to improve its penetration into a molding machine.
Pelletized ones are preferably used. The composition for molded bodies of the present invention is used as a material for molded bodies in extrusion molding or injection molding, but in extrusion molding, the matte state tends to be affected by the contact state with the molding roll after extruding the resin. It is suitable for injection molding without such problems, and is preferably used as an acrylic resin composition for injection molded articles.

In the present invention, the acrylic resin composition is not subjected to matte processing under normal injection conditions using a normal injection molding machine. By injection molding into a mold cavity, it is possible to produce an acrylic resin molded product with excellent matte properties. Agrill resin molded products having a uniform matte surface can be obtained by molding pellets into pellets using an extrusion molding machine and injection molding them into a mirror mold A-Yahidei using an injection molding machine.

The acrylic resin molded product of the present invention obtained as described above has good mechanical strength and solvent resistance, and exhibits a matte surface with excellent anti-glare properties, but When the refractive index of the fine particles is approximately the same, it can be easily made transparent by polishing a predetermined surface portion after molding, which is also advantageous when producing a molded article having a partially transparent portion.

(Example) Hereinafter, the present invention will be explained in more detail with reference to Examples.

In addition, "%1" and "part" in (゛) in Examples and Comparative Examples
All represent "% by weight" and "parts by weight", respectively, and the performance of the acrylic resin molded products obtained in Examples and Comparative Examples was measured and evaluated by the following method.

K1〥1 Indoors, reflect a fluorescent light on the sample soil and visually observe it.
Express the matte condition of the sample using the following symbol.

○...The outline of the fluorescent lamp is not recognized or almost recognized -1
,2-,-- I can't believe it.

△: The outline of the fluorescent lamp is recognized, but it is unclear, and the surface is uneven.

×: The outline of the fluorescent lamp is clearly recognized, and there are almost no irregularities on the surface.

Integrating sphere type light transmittance measuring device in accordance with JISK7105 (Murakami Color Research Institute: Light transmittance/reflection reprint RM-1
5), and the total light transmittance, parallel light transmittance, and haze value were calculated.

Glossiness: 60° using a glossmeter (Ska tester ■: SM Color Computer) in accordance with the glossiness measurement of JISK7105.
-Measure at 60° reflection.

The ten-point average roughness (Rz) was measured using a surface roughness meter (Tsuki Kosaka Research Institute, Universal Surface Profile Measuring Instrument 5E-3C) in accordance with JIS B O60.

Example 1 1837 g of polyvinyl alcohol (PTA420 manufactured by Kuraray Co., Ltd.) with a degree of polymerization of 2120 and a degree of saponification of 79.4% was added to a separable flask of 2625 m using a !V suspension dispersant.
, Q were dissolved in distilled water, and the monomer system was stearyl methacrylate 300 m, Q, ethylene glycol dimethacrylate h 300 m 41, l.ruene 400 m
200 g of the solution was added. This mixed solution was dispersed using a lab body spazer (Model X-1020, manufactured by Mitamura Riken ■) until the maximum particle size when observed under a microscope was 20 μm. A thermometer, a stirrer, and a cooling tube were attached to the flask, and the polymerization reaction was carried out at 80°C for 6 hours under a nitrogen stream.The resulting slurry was suctioned and filtered, and the fine particles separated by the furnace were poured into distilled water again. Disperse (=f) Wash and filter the attached polyvinyl alcohol. Vacuum dry this at 100°C for 2 times to evaporate the diluent 1 to luene and observe with an optical microscope. average particle size of 7 μm (10 μm7
Cross-linked polymethyl methacrylate fine particles with a weight distribution of 84% or more of the non-grooved particles were obtained.

= 14- To 100 parts of methyl methacrylate polymer containing 5% methyl acrylate, 0.1 part, 1 part, 2 parts, 5 parts, and 10 parts of the above crosslinked polymethyl methacrylate fine particles were added, respectively. After mixing and stirring with a mixer, each was extruded into pellets using an extruder (Chuo Kikai Seisakusho V: VSK-40), and the pellets were then molded into an injection molding machine (manufactured by Toshiba Machine Corporation: 1S-) equipped with a mold having a mirror cavity.
25EP) at a molding temperature of 200 to 240°C and a mold temperature of 50°C to obtain a flat plate molded product with a thickness of 2 mm.

The performance evaluation results of these molded products are shown in Table 1.
In the cases other than those containing fine particles, a surface having a fine and uniform matte surface was obtained.

Example 2 With respect to 100 parts of methyl methacrylate polymer containing 5% methyl acrylate, the polymerization degree was 9300, the particle size distribution was 1 to 24 μm, and the average particle diameter was 7 μm (the 10 μm Mihama particles had a weight distribution of 82%). ) high polymerization degree polymethyl methacrylate fine particles (building block = 15- manufactured by Seishin Kogyo ■: Technopolymer MB-8, true specific gravity 1.1
Add 1 part, 2 parts, 5 parts, 10 parts, 15 parts, and 20 parts of 9>, mix with a Henshil mixer, pelletize each with an extruder, and injection mold the pellets in the same manner as in Example 1. A flat plate molded product with a thickness of 2 III m was obtained. The performance evaluation results of these molded products are shown in Table 1, and all of them had fine and uniform matte surfaces.

Example 3 For 100 parts of methyl methacrylate polymer containing 5% methyl acrylate, a crosslinked polyester having a particle size distribution of 2 to 40 μm and an average particle diameter of 11 μm (particles smaller than 10 μm account for 65% of the weight distribution) 1 part, 5 parts, 10 parts, 15 parts, and 20 parts of methyl methacrylate-1 microparticles (manufactured by Matsumoto Yushi Seiyaku ■: Microsphere R1-305) were added, mixed and stirred with a Henshil mixer, and then extruded using an extruder. The pellets were made into pellets 1 to 1, and the pellets were injection molded in the same manner as in Example 1 to obtain a flat plate molded product with a thickness of 2 mm+. The performance evaluation of these molded products is shown in Table 1, and all of them had fine and uniform matte surfaces.

Real color example 4 Monomer system: 30% methyl methacrylate, 50% ethylene glycol, 3% ethyl acrylate, 16% styrene
Crosslinked polymer fine particles with a particle size of 2 to 26 μm and an average particle size of 10 μm (particles smaller than 10 μm are 70% in weight distribution) were obtained in the same manner as in Example 1 except that no diluent was used.
The above fine particles were added at 0.1 parts, 1 part, and 5 parts per 100 parts of methyl methacrylate polymer containing 5% methyl acrylate.
Example 1
Perform injection molding in the same manner as above to obtain a flat plate molded product with a thickness of 2+ nm.

The performance evaluation of these molded products is shown in Table 1, and the molded products containing one or more parts of fine particles had matte performance and a translucent milky white color.

Example 5 The same method as Example 4 was used except that the monomer system was 80% methyl methacrylate and 20% neopentyl glycol dimethacrylate, with a particle size of 2 to 30 μm and an average particle size of 10.
μm (particle size less than 10 μm is 70% in weight distribution) crosslinked polymethyl methacrylate fine particles were obtained, and 1 part, 5 parts of the above fine particles were added to 100 parts of methyl methacrylate polymer containing 5% methyl acrylate 10 parts of each were added, mixed and stirred with a Henshil mixer, and then pelletized with an extruder, and a flat plate molded product with a thickness of 2 mm was obtained in the same manner as in Example 1. The evaluation results of the appearance, light transmittance, and gloss of these molded products showed similar results to the performance evaluation corresponding to the same amount of fine particles added in Example 3.

Example 6 To 100 parts of pelletized methyl methacrylate polymer containing 5% methyl acrylate, 2 parts of fine particles prepared by mixing the fine particles of Example 2 and the fine particles of Example 3 in a ratio of 1=1 were added. After mixing and stirring using a sill mixer, the mixture was pelletized using an extruder, and a flat plate molded product with a thickness of 2 mm was obtained in the same manner as in Example 1. This molded article has a fine and uniform matte surface and exhibits a total light transmittance of 90%, a parallel light transmittance of 87%, a haze value of 4%, and a gloss level of 1-12.

Comparative Example 1 Cross-linked polymethyl methacrylate fine particles with an average particle diameter of 1°0 μm (Tsukusui Kaseihin Kogyo ■: DEKUBORIMER-MBX-1, 00) 1 part, 2 parts, 5 parts
Example J
Use the same method as above to obtain a flat plate molded product with a thickness of 2 mm. The performance evaluation results of these molded products are shown in Table 1, and the results showed that the surfaces did not have a uniform matte surface, but had a mottled appearance as if the particles were aggregated.

Comparative Example 2 Methyl methacrylate vehicle combination containing 5% methyl acrylate], the degree of polymerization was i1. ioo.

Average particle size 1 with main particle size distribution between 70 and 15μfn
10 μm high polymerization degree polymethyl methacrylate fine particles (
After adding 1 part, 3 parts, and 10 parts of Mitsubishi Rayon Niacrycon) and mixing with a Henshil mixer, they were made into pellets using an extruder and molded in the same manner as in Example 1 to form a flat plate with a thickness of 2II and 1 m. I got the item. The performance evaluation results of these molded products are shown in Table 1, and the surface conditions were the same as in Comparative Example 1.

Comparative Examples 3 and 4 Using inorganic fine powder instead of polymer fine particles-r, Example 1
Table 1 shows the performance evaluation results of molded products obtained by mixing and stirring in the same manner as above to form pellets and then injection molding.

As the inorganic powder, silica (Aerosil (11: Aerosol R-972 in Japan) was used in Comparative Example 3, and barium sulfate (precipitated barium sulfate manufactured by F!'I Kagaku ■) in Comparative Example 4 was used.

For products containing inorganic powder, it is necessary to increase the amount added in order to achieve a sufficiently matte state, but in this case, the translucency decreases, and the mechanical strength is also lower than that of products containing fine polymer particles. Don't fall.

Comparative Example 5 Table 1 shows the performance of commercially available mold transfer sheets 1 to 1. city-20
-,- Twin crystal A is an example of a light matte state, and commercial product I3 is an example of a hard matte state.

Example 7 For 100 parts of methyl methacrylate polymer containing 5% methyl acrylate, 1 to 20 μm at a degree of polymerization of 9000
Highly polymerized polymethyl methacrylate fine particles and titanium oxide (Ishihara Sangyo ■v:
: r-t-630) were added to each, and mixed and stirred using a Henshil mixer in the same manner as in Example 1, pelletized using an extruder, and the pellets 1 to 1 were injection molded to a thickness of 2.
We can produce mm flat plate molded products. The performance evaluation results of these molded products are shown in Table 2, and in the case of this example, the glossiness of the IJ changes greatly depending on the amount of fine particles added, but the surface roughness hardly changes and the surface irregularities do not change. It was discovered that they are the same, a unique feature that cannot be found anywhere else.

Example 8 Particle size distribution from 3 to 45 μIn and average particle size 20 μm'
A flat plate molded product with a thickness of 2 mm was obtained in the same manner as in Example 7, except that crosslinked polymethyl methacrylate l-fine particles with a weight distribution of 3% (weight distribution of particles less than 1.0 μm) were used.
The performance evaluation results of these molded products are shown in Table 2.

Example 9 With a degree of polymerization of 8500 and a particle size distribution of 2-25 μm, the average particle diameter was 8 μm (particles smaller than 10 μm accounted for 73% of the weight distribution).
) and 08 parts of calcium carbonate (manufactured by Nemoto Tokushu Kagaku ■: DNF-7) were used to obtain a flat plate molded product with a thickness of 2 mm. The performance evaluation results of the product are
Shown in the table.

Example 10 A thickness of 2 + nm was prepared in the same manner as in Example 9 except that 0.35 parts of black dye pigment was used in place of calcium carbonate.
Flat plate molded products were obtained, and the performance evaluation results of these molded products are shown in Table 2.

Example 11. Comparative Example 6 The mechanical strength of the molded product containing the polymer fine particles of Examples 2 and 3 and the molded product containing the inorganic powder of Comparative Example 3 was determined by AS.
Measured according to TMD638 and D256. The results are shown in the table below, and it can be seen that the one containing fine polymer particles has better mechanical resistance than the one containing inorganic powder.

*Values without notch are shown. .

Example 12. Comparative Example 7 For the purpose of evaluating solvent resistance to brake oil and ingropyl alcohol, a Tambell-shaped molded product containing polymer fine particles of Example 130 and a Tambell-shaped molded product containing no fine particles were used, and Tambell-23- Supporting one wheel, load 500g, fulcrum stress 271kg/Cl
The breaking time of the tambell was measured under the conditions of 1.

The results are shown in the table below, and it can be seen that the rupture time is longer and the solvent resistance is improved in those containing polymer fine particles compared to those without polymer particles.

(Effects) As explained below, the present invention provides fine particles of crosslinked Nisder methacrylate polymer having a particle size of 1 to 50 μm and/or highly polymerized Nisder methacrylate polymer, based on 100 parts by weight of methyl methacrylate polymer. 0.5 polymer fine particles
Since this is an acrylic resin composition for molded objects that contains ~15 parts by weight and has excellent matte properties, the matte state can be changed by changing the particle size and amount of the fine polymer particles added. Thus, compositions for molded objects having various matte states can be easily provided. It is particularly useful as an injection molding material with excellent mass productivity.

In addition, since the acrylic resin molded product with excellent matte properties is obtained by injection molding the above-mentioned acrylic resin composition for molded objects with excellent matte properties, there is no need to perform secondary heat processing. It is a molded product that can be supplied in large quantities at low cost because it is a product, and has a matte surface with excellent solvent resistance and mechanical strength.It is a molded product that has a matte surface of various types. Alternatively, it is useful as an instrument cover, etc. In particular, when a transparent acrylic resin is used as the base resin, it is useful as a molded product with a high energy-saving effect due to its lack of translucency. can be easily made transparent by polishing the predetermined front and back parts after molding, so molded products with partially transparent parts can be
, it can be useful to build.

Furthermore, the present invention is a method for producing an acrylic resin molded product with excellent matte properties by injection molding the above-mentioned acrylic resin composition into a mold cavity that has not been subjected to a matte finish. It is possible to manufacture molds at low cost without the need for thorough mirror polishing, and by changing the molding material in the same mold, it is possible to manufacture a variety of matte and mirror-finished products. Therefore, it is advantageous to be able to provide an acrylic resin molded product that is inexpensive, easy to use, and has a matte surface condition that can be produced in a variety of furnaces.

Claims (5)

[Claims] (1) 0.5 to 15 parts by weight of crosslinked methacrylic ester polymer particles and/or highly polymerized methacrylic ester polymer particles having a particle size of 1 to 50 μm to 100 parts by weight of methyl methacrylate polymer. An acrylic resin composition for molded objects with excellent matte properties. (2) The acrylic resin composition according to claim 1, wherein the fine particles are crosslinked polymer fine particles and/or high polymerization degree polymer fine particles containing methyl methacrylate as a main component. (3) The acrylic resin composition according to claim 1, wherein the fine particles are crosslinked polymethyl methacrylate fine particles and/or highly polymerized polymethyl methacrylate fine particles. (4) An acrylic resin molded article with excellent matte properties obtained by injection molding the acrylic resin composition according to claims 1 to 3. (5) In a method for obtaining an acrylic resin molded article by injection molding an acrylic resin material, the acrylic resin composition according to any one of claims 1 to 3 is injection molded into a mold cavity that is not subjected to matte processing. A method for producing acrylic resin molded products with excellent matte properties.