JPH0569845B2 - - Google Patents

Description

[Detailed description of the invention]

(Field of Industrial Application) The present invention relates to a methacrylic resin molded article having excellent transparency, weather resistance, scratch resistance, and high heat resistance, and a method for producing the same. (Conventional technology) Acrylic resin has excellent appearance, transparency, and weather resistance, so it is used for glazing, light covers,
It is used in a wide range of fields, both indoors and outdoors, such as decorative items, but compared to inorganic glass, it not only has poor heat resistance but also poor scratch resistance. development is expected. Therefore, various methods to improve these drawbacks have been studied. In general, synthetic resin molding materials are molded using a molding machine such as a press molding machine, an injection molding machine, an extruder, or a vacuum molding machine, or by polymerization and solidification in a mold, and then a scratch-resistant film is formed. After coating the surface of the molded article with the raw material by a spray method, dipping method, etc., the coating film is polymerized and solidified by electron beams or heat to form a scratch-resistant film. The problem with this method is that, first, the polymerization process to form a scratch-resistant film is performed after the molding process, so expensive equipment such as painting equipment, curing equipment, and dust removal equipment including these equipment is required for molding. It is necessary to provide it separately, and complicated management of the viscosity of the curing liquid, etc. is required. As a way to improve these,
No. 14617 and No. 54-14618, a mold is coated with a raw material for forming an abrasion-resistant film, covered with a synthetic resin film, or prepolymerized under an inert gas atmosphere to form a gel. The film or inert gas is removed at a gel fraction of about 40-95%, and then post-cured to a gel fraction of 85% or higher, so that it will not swell or dissolve with the base resin raw material that will be injected later. There is a method of obtaining a synthetic resin molded article having a wear-resistant surface, which involves injecting a base resin raw material into a mold and polymerizing and solidifying it. However, this method inevitably involves a complicated process in which two stages of polymerization, prepolymerization and postpolymerization, must be performed in order to obtain scratch resistance. In this case, prepolymerization alone causes appearance defects such as irregularities and cracks on the surface, uneven abrasion resistance, and insufficient scratch resistance. A second problem is insufficient adhesion between the base resin and the scratch-resistant coating. One way to improve this point is to provide a layer between the scratch-resistant film and the base resin that can be bonded to both.
This requires performing the coating and film polymerization steps two or more times, resulting in low productivity. Moreover, this method cannot prevent pinholes that normally occur in the scratch-resistant coating due to defects such as dust, and the adhesive layer is easily attacked by solvents, so the solvent resistance is significantly reduced in those areas. There are drawbacks. Furthermore, as in Japanese Patent Publication No. 53-9876, a method has been proposed in which improved adhesion can be obtained by forming a scratch-resistant coating on the surface of a molded product that has been irradiated with ultraviolet rays. However, this method requires irradiation of ultraviolet rays to both the molded product and the film separately, and the process is complicated. In addition, exposure tests revealed that molded articles with scratch-resistant coatings formed using this method were not useful for improving scratch resistance. Furthermore, in order to obtain adhesion, a solvent that is highly soluble in the molding base resin is sometimes added to the raw material for the scratch-resistant coating, but if it is too strong, it may cause cracks and loss of surface smoothness. If the solvent is weak, adhesion cannot be obtained, requiring a complicated combination of solvents, and at the same time, consideration must be given to processing equipment such as exhaust of vaporized solvent. In addition, methacrylic resins whose main component is methyl methacrylate are used in various fields such as lighting covers and automobile parts due to their excellent weather resistance and outstanding transparency. Because it is a polymer, it is not suitable for applications that require relatively high heat resistance, solvent resistance, impact resistance, and surface hardness. For example, regarding heat resistance
It cannot be used in applications that are exposed to high temperatures exceeding 100°C for long periods of time, such as automobile headlight covers and solar water heater covers. Conventionally, with the aim of improving the heat resistance of methacrylic resins, methods have been proposed in which methyl methacrylate is copolymerized with α-methylstyrene (US Pat. No. 3,135,723), and methyl methacrylate is copolymerized with α-methylstyrene and maleic anhydride (US Pat. No. 3,135,723). Tokuko Showa 45-31953
A number of methods are known, including a method of copolymerizing methyl methacrylate with α-methylstyrene and maleimide (Japanese Patent Publication No. 48-95490). However, although all of these methods improve heat resistance, the polymerization rate is extremely slow, the polymerization rate does not increase and a high polymerization rate cannot be obtained, or the polymer cannot be efficiently produced in a relatively short time. Even if it is obtained, there are problems such as strong discoloration of the polymer and reduction in transparency, weather resistance, surface hardness, mechanical strength, etc. Separately, a method for manufacturing molded articles using a gel-like polymer obtained by partially crosslinking an alkyl methacrylate monomer or syrup with a crosslinking agent has been proposed (Japanese Patent Laid-Open No. 60-212128). There is. According to this method, a cross-linked molded product with excellent transparency and heat resistance can be obtained, but the method of coating the molded product to form a scratch-resistant film has a problem of low adhesion with the scratch-resistant film. . For this reason, in order to apply the film to the surface of the molded article, it is necessary to carry out the complicated preliminary treatment described above to improve the adhesion. (Problems to be Solved by the Invention) Therefore, an object of the present invention is to obtain a methicrylic resin molded product having excellent both scratch resistance and heat resistance, and in particular, to obtain a methicrylic resin molded product having an excellent scratch resistance and heat resistance. An object of the present invention is to provide a highly heat-resistant methacrylic resin molded product. Another object of the present invention is to provide a method for easily manufacturing such molded articles. (Means for solving the problems) These problems are caused by the crosslinking of (A) and (a) in which the scratch-resistant layer forming material has a molecular weight of 150 or more and has at least two (meth)acryloyloxy groups per molecule. a polymerizable compound, (b) a mixture with other polymerizable monomers containing 30% by weight or more of the crosslinked polymerizable compound; and
(c) selected from the group consisting of partial polymers thereof, and the number x of (meth)acryloyloxy groups in the crosslinked polymerizable compound and the polymerization rate y of the scratch-resistant layer forming material
(%) is a scratch-resistant layer forming material that satisfies the following formula or y≦70 (2≦x≦3.5) () y≦−7.5x ² +52x−18 (3.5≦x≦6) (); (B), () A resin raw material selected from the group consisting of an alkyl methacrylate monomer, a mixture of an alkyl methacrylate as a main component with an α,β-ethylenically unsaturated monomer, and a syrup containing the polymer. and () an acrylic partially crosslinked gel polymer obtained by mixing 3 to 30 parts by weight of a crosslinking agent to 100 parts by weight of the resin raw material, partially polymerizing it, and stopping the polymerization at a gel fraction of 15 to 95%. A methacrylic resin made of a crosslinked polymer whose surface is at least partly covered with an abrasion-resistant layer obtained by simultaneously polymerizing it under conditions that impart a desired shape by bringing it into contact with a molding base material made of coalescence. This is achieved by obtaining a shaped article. These purposes are as follows: (A) the scratch-resistant layer forming material is a cross-linked polymerizable compound having a molecular weight of 150 or more and at least two (meth)acryloyloxy groups per molecule; Mixtures with other polymerizable monomers containing 30% by weight or more of the compound and
(c) selected from the group consisting of partial polymers thereof, and the number x of (meth)acryloyloxy groups in the crosslinked polymerizable compound and the polymerization rate y of the scratch-resistant layer forming material
(%) is a scratch-resistant layer-forming material that satisfies the following formula or y≦70 (2≦x≦3.5) () y≦−7.5x ² +52x−18 (3.5<x≦6) (); (B), () A resin raw material selected from the group consisting of an alkyl methacrylate monomer, a mixture of an alkyl methacrylate as a main component with an α,β-ethylenically unsaturated monomer, and a syrup containing the polymer. and () an acrylic partially crosslinked gel polymer obtained by mixing 3 to 30 parts by weight of a crosslinking agent to 100 parts by weight of the resin raw material, partially polymerizing it, and stopping the polymerization at a gel fraction of 15 to 95%. A molded product made of a crosslinked polymer, at least a part of whose surface is covered with an abrasion-resistant layer, obtained by simultaneously polymerizing it under conditions that impart a desired shape by bringing it into contact with a molding base material made of coalescence. The present invention is also achieved by a method for producing a methacrylic resin molded article. (Function) In the molding material (B) made of an acrylic partially crosslinked gel polymer in the present invention, the resin raw material, ()
The monomer used as the alkyl methacrylate is a single alkyl methacrylate or a mixture containing an alkyl methacrylate as a main component and an α,β-ethylenically unsaturated monomer that can be copolymerized with the alkyl methacrylate. In the monomer mixture,
The proportion of alkyl methacrylate is 50 mol% or more,
Preferably it is 60 mol% or more. Alkyl methacrylates include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, sec-butyl methacrylate, tert-butyl methacrylate, lauryl methacrylate, cyclohexyl methacrylate, etc., and lower alkyl acrylates, Particularly preferred is methyl methacrylate. Examples of copolymerizable monomers include methyl acrylate,
Ethyl acrylate, propyl acrylate, n
- Alkyl acrylate such as butyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, cyclohexyl acrylate, 2-
Hydroxyalkyl acrylate of hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 3-hydroxypropyl acrylate, 4-hydroxybutyl methacrylate, 2-
These include hydroxyalkyl methacrylates such as hydroxy-3-chloropropyl methacrylate. In addition, as a syrup containing a polymer of the alkyl methacrylate or a monomer mixture containing alkyl methacrylate as a main component, it is generally
~20000 centipoise viscosity, and 3~40
% by weight of the polymer, preferably from 6 to 20% by weight of the monomer. The crosslinking agent ( ) used in the present invention has at least two (meth)acryloyl groups in the molecule, and preferably has 10 or less atoms between the (meth)acryloyl groups, for example, by the following formula: ~ MA-O(-CH ₂ )- _o O-MA () (where n is an integer from 3 to 6, and MA represents a methacryloyl group.)

[Chemical formula] [Here, R ₁ is H, CH ₃ , C ₂ H ₅ or CH ₂ OH
, R ₂ is H, CH ₃ ,

[Formula] (R ₄ represents H or CH ₃ or CH ₂ OH, R ₃ represents H or CH ₃ , R ₁ , R ₂ and R ₃ are not hydrogen at the same time, (M)A is represents a methacryloyl group or an _acryloyl group.] (M)AO( _-CH2CH2O ) _-o (M)A () (where n is 1 or 2, and (M)A represents a methacryloyl group or an acryloyl group. It is a monomer represented by: Glycol dimethacrylate, dimethylolethane dimethacrylate, 1,1-dimethylolpropane dimethacrylate, 2,2-dimethylolpropane dimethacrylate, trimethylolethane tri(meth)acrylate, trimethylolpropane tri(meth)
Acrylate, phthonimethylolmethane tri(meth)acrylate. Examples include tetramethylolmethane dimethacrylate, ethylene glycol di(meth)acrylate, and diethylene glycol di(meth)acrylate. The blending amount of these crosslinking agents is as follows:
3 to 30 parts by weight, preferably 10 to 100 parts by weight
If the amount is less than 3 parts by weight, the heat resistance will not be sufficient, and if it exceeds 30 parts by weight, a long time polymerization will be required and there will be a problem of poor weather resistance. In the present invention, a polymerization initiator is used when preparing the partially crosslinked gel polymer and when polymerizing it by contacting it with the scratch-resistant layer-forming material. This can be one or a mixture of two or more selected from conventional low-temperature active polymerization initiators and high-temperature active polymerization initiators. In general, low temperature active polymerization initiators are suitable for the preparation of partially crosslinked gel polymers, and peroxides with a decomposition temperature below 50°C, preferably 26-45°C, especially 26-41°C to obtain a 10 hour half-life and azo compound radical polymerization initiators are preferred. The amount used is 0.002 to 1% by weight based on the total amount of resin raw material () and crosslinking agent (), preferably
It is 0.005-0.1% by weight. Examples of such low-temperature active polymerization initiators include () acetylcyclohexylsulfonyl peroxide, isobutyryl peroxide, cumyl peroxyneodecanoate, diisopropyl peroxydicarbonate, dimyristyl peroxydicarbonate, 2,2' -Azobis(4-methoxy-2,4-dimethylvaleronitrile),
() di-(2-ethoxyethyl) peroxydicarbonate, di-(methoxyisopropyl) peroxydicarbonate, di-(2-ethylhexyl) peroxydicarbonate, () di-(3-
Methyl-3-methoxybutyl) peroxydicarbonate, t-butyl peroxydecanoate,
2,2'-azobis(2,4-dimethylvaleronitrile), etc., and among these, compounds belonging to the groups () and () are preferred, and compounds belonging to the group () are particularly preferred. . The high temperature active polymerization initiator is suitable for polymerization under molding conditions in the present invention, and has a decomposition temperature of 60 to 220°C, preferably 70 to 170°C. Its usage is
The amount is 0.02 to 5.0% by weight, preferably 0.05 to 4% by weight, based on the total amount of the resin raw material () and the crosslinking agent (). Examples of such high temperature active polymerization initiators include () t-butyl mill peroxide, diisopropylbenzene hydroperoxide, di-
t-Butyl peroxide, p-menthane hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, 2,5-dimethylhexane-2,5-dihydroperoxide, cumene hydroperoxide, t -butyl hydroperoxide, 1,1,2,2-tetraphenyl-1,2-ethanediol, ()1,
1-bis(t-butylperoxy)-3,3,5
-trimethylcyclohexane, t-butylperoxylaurate, cyclohexanone peroxide, t-butylperoxyisopropyl carbonate, 2,2-bis(t-butylperoxy)octane, t-butylperoxyacetate, 2,
2-bis(t-butylperoxy)butane, t-
Butyl peroxybenzoate, di-t-butyl diperoxyisophthalate, methyl ethyl ketone peroxide, α,α'-bis(t-butylperoxyisopropyl)benzene, dicumyl peroxide, ()t-butyl hydroperoxide, m-toluoyl peroxide, benzoyl peroxide, t-butyl peroxyylisobutyrate, octanoyl peroxide, lauroyl peroxide, succinic acid peroxide, acetyl peroxide, 1,
Examples include 1'-azobis(cyclohexane-1-carbonitrile), among which compounds belonging to the () and () groups are preferred, and compounds belonging to the () group are particularly preferred. In the present invention, the partially crosslinked gel polymer is prepared by heating and polymerizing a mixture of the resin raw material () and the crosslinking agent () in the presence of a polymerization initiator. This polymerization reaction is 10
It is carried out at a temperature of ~80°C, preferably 35-65°C, for 10-200 minutes, preferably 20-150 minutes. here,
When both low-temperature-active and high-temperature-active polymerization initiators are used together, almost all of the low-temperature-active polymerization initiator is consumed, but the high-temperature-active polymerization initiator does not decompose at the above reaction temperature and remains as it is, resulting in subsequent polymerization. Used as a polymerization initiator under molding conditions. The gel fraction of partially crosslinked gel polymer is 15-95%,
Preferably it is 15-75%. When the gel fraction is less than 15%, foaming during molding and cracking and deformation of the molded product are likely to occur, and when it exceeds 95%, good flow is not exhibited during molding. A partially crosslinked gel polymer having a desired polymerization rate can be obtained by stopping the polymerization reaction at the desired polymerization rate by rapid cooling, or by selecting the amount of low-temperature active polymerization initiator, polymerization temperature, and polymerization time. ,
Further, it can be easily obtained by adding a specific amount of a specific regulator when heating and polymerizing the mixture of the resin raw material () and the crosslinking agent () in the presence of the polymerization initiator. Specific such regulators include 1,4,8-P-mentadiene, 2,6-dimethyl-2,4,6-octatriene, 1,4-P-mentadiene, 1,4-cyclohexadiene and There is an α-methylstyrene dimer. Such a regulator is used in an amount of 0.0001 to 0.0001 to the total amount of the resin raw material () and the crosslinked polymerizable compound ().
It can be used in a range of 0.5% by weight, preferably 0.001-0.2% by weight, most preferably 0.005-0.1% by weight. If the amount of the regulator added is less than 0.0001% by weight, the desired regulating effect cannot be achieved, and if the amount added exceeds 0.5% by weight, the desired gel content cannot be achieved. Since this forming base material is non-sticky and has shape-retaining properties, it can be handled in any desired shape such as a sheet, rod, block, or pellet. Further, for convenience in molding, the molding base material may be crushed or kneaded prior to molding, or colorants and other additives may be added as necessary. The scratch-resistant layer-forming material has a molecular weight of 150 or more, preferably 200 to 2000, most preferably 200 to 1200, and a molecular weight of 1
A cross-linked polymerizable compound having at least two acryloyloxy groups or methacryloyloxy groups per molecule, or a mixture with other polymerizable monomers having 30% by weight or more of said compound, or a partial polymer thereof; The average number of (meth)acryloyloxy groups in the polymerizable compound or mixture is preferably 2.0 to 6.0, preferably 2.5 to 5.5. 2
If it is less than 6.0, sufficient scratch resistance will not be obtained, and if it exceeds 6.0, it will be difficult to proceed the reaction sufficiently, and the occurrence of yellowing, cracks, etc. due to weather resistance will increase. Cross-linked polymerizable compounds include those in which the residue that binds the acryloyloxy group or methacryloyloxy group is a hydrocarbon or a derivative thereof, and the molecule contains an ether bond, thioether bond, ester bond, amide bond, urethane bond, etc. , or may have an isocyanuric acid skeleton or a melamine skeleton. For example, trimethylolpropane triacrylate, 1,6-hexanediol acrylate, neopentyl glycol diacrylate, hydroxypivalate neopentyl glycol diacrylate, dipentaerythritol hexaacrylate, caprolactam-modified dipentaerythritol hexaacrylate, trisacryloyl cyanurate, isocyanurate. Examples include (meth)acryoxy compounds having a nuric acid skeleton, epoxy acrylates, and polyester acrylates. Examples of polymerizable monomers that can be mixed with the crosslinking polymerizable compound include metal methacrylate, tetrahydrofurfuryl acrylate, ethyl carbitol acrylate, phenyl carbitol acrylate, hydroxyethyl acrylate, 2-hydroxy-3 -Phenoxypropyl acrylate and the like. However, in the scratch-resistant layer forming material,
The number x of (meth)acryloyloxy groups and the polymerization rate y (%) of the scratch-resistant layer forming material are expressed by the following formula or y≦70 (2≦x≦3.5) () y≦−7.5x ² +52x− 18 (3.5<x≦6) () It is necessary to satisfy. Within this range, sufficient adhesion to the molding base material can be obtained. This polymerization rate y is expressed as a percentage of the amount of remaining double bonds measured from the peak height of the absorption band attributable to C=C near 1620 nm in the infrared absorption spectrum, and is obtained by subtracting the remaining double bonds from 100. . The polymerization rate can be adjusted by coating the mold with a scratch-resistant layer-forming material in advance before putting the molding base material into the mold, and polymerizing it using heat or a photopolymerization initiator. It may also be applied onto the surface of a synthetic resin film and polymerized in advance using the same method. In the present invention, the scratch-resistant layer-forming material and the molding base material made of a partially crosslinked gel-like polymer are simultaneously polymerized while in contact with each other. More specifically, the scratch-resistant layer is formed so that at least a part of the surface of the molded article made of the crosslinked polymer formed from the molding base material is covered by the polymer layer formed from the scratch-resistant layer-forming material. At least a portion of the surface of the layer-forming material and the molding base material are brought into contact with each other, and both are simultaneously polymerized. This polymerization is carried out under conditions that allow moldings of desired shapes to be obtained. For example, the following method can be used. (1) 80 to 160 for press molding machines or injection molding machines, etc.
A scratch-resistant layer-forming material is applied in advance to the mold heated to ℃ by appropriate means such as spraying or rolling.
After polymerization within the above range, the molding base material is introduced into a mold and molded; (2) an appropriate means such as spraying or rolling the abrasion-resistant layer forming material onto the surface of the molding base material; A method of coating and molding by putting it into a press molding mold heated to 80 to 160 degrees Celsius. If the stretching ratio of the molding base material exceeds 72%, unevenness may occur between areas with and without the scratch-resistant layer. (3) Paint on a film of synthetic resin etc. in advance,
After polymerizing with ultraviolet rays or heat to the desired polymerization rate, place the forming base material on top and heat at 80~160℃.
A method of molding by putting it into a heated mold. (4) In advance, the molding base material is placed in a mold heated to 80 to 160°C, and after further polymerization, the mold is opened and the scratch-resistant layer forming material is placed on the mold surface or This can be done by appropriate means such as spray painting on the surface of the molding base material, or by injecting it between the mold and the molding base material, and then closing the mold again. Thereafter, in order to further improve the heat resistance of the molded substrate, post-polymerization is performed at 120 to 140° C. for 3 to 12 hours to form a molded article. As the initiator for polymerizing the scratch-resistant layer forming material, the low temperature active polymerization initiator and the high temperature active polymerization initiator used to obtain the partially crosslinked gel polymer can be used, and a photoinitiator can be used. You can also do it. As a photopolymerization initiator, 1-hydroxycyclohexyl phenyl ketone, benzyl dimethyl ketal, benzophenone, Michler's ketone, benzoin, acetophenone, 2-hydroxy-2-methyl-phenyl-propane.
1-one, 2,4-diethyloxanthone, 4-
Examples include chlorthioxanthone. The blending range of the low-temperature active polymerization initiator is preferably 0.5 to 3% by weight, preferably 1 to 2% by weight, based on the crosslinking polymerizable compound or the mixture with the polymerizable monomer. If it is less than 0.5% by weight, the polymerization of the scratch-resistant layer will be delayed and sufficient scratch resistance will not be obtained. Moreover, if it exceeds 3% by weight, polymerization will begin before the coating is uniformly applied to the mold, making it impossible to obtain a smooth surface of the layer. The blending range of the high temperature active polymerization initiator is preferably 0.5 to 5% by weight, preferably 2 to 4% by weight. 0.5
If it is less than % by weight, sufficient polymerization will not occur within the molding time, resulting in a decrease in scratch resistance. If it exceeds 5% by weight, the layer will harden quickly, resulting in insufficient adhesion between the molding base material and the layer. The photopolymerization initiator is used in methods (1) and (3) in which molding of the molding base material and formation of the scratch-resistant layer are performed simultaneously.
It is desirable to use this method in order to shorten the molding time. The blending amount is preferably 0.2 to 1.0% by weight, preferably 0.3 to 0.6% by weight, although it depends on the output of the lamp that generates ultraviolet rays. If it is less than 0.2% by weight, fine irregularities appear on the layer and a smooth surface cannot be obtained. Also, if it exceeds 1.0% by weight,
Curing is rapid and adhesion between the layer and the molding substrate is insufficient. In order to color the molded article, a coloring agent may be added to the molding base material or a coloring agent may be added to the scratch-resistant layer forming material. Further, deterioration inhibitors such as a leveling agent, an ultraviolet absorber, and an antioxidant can be added to the scratch-resistant layer forming material, if necessary. According to the method of the present invention, the scratch-resistant layer has excellent hardness and abrasion resistance, has extremely good adhesion to acrylic, and has excellent weather resistance and heat resistance without deterioration of solvent resistance due to pinholes. acrylic resin products can be easily made. (Example) Hereinafter, the present invention will be explained in more detail with reference to Examples. Examples 1 to 3 and Comparative Example 1 80 parts by weight of methyl methacrylate syrup containing 8% by weight of polymethyl methacrylate having an average degree of polymerization of about 8000, 20 parts by weight of 2,2-disimethylolpropane dimethacrylate, and 1,4, A mixture of 0.08 g/Kg of 8-p-mentadiene, 0.05 g/Kg of cumyl peroxyneodecanoate, and 2 g/Kg of di-t-butyl peroxide was mixed and dissolved into a plate with a thickness of 6
Two glass plates with a size of 450 x 350 mm in mm,
A gasket made of vinyl chloride resin is used, and the spacing is
A partially crosslinked gel polymer with a predetermined gel fraction can be obtained by injecting the polymer into a cell assembled to a thickness of 10 mm, placing the cell in a constant temperature water bath preheated to 50°C, and varying the removal time. Ta. These gel fractions are measured in a predetermined amount (10 to 15
Ratio between the weight of the partially crosslinked gel polymer and the weight of the undissolved matter when the partially crosslinked gel polymer g) was extracted in acetone at 50°C for 6 hours and further vacuum dried at 50°C for 12 hours. was calculated as a percentage. The partially crosslinked gel polymer was cut into 200 x 180 mm pieces, and 70 parts by weight of dipentaerythritol hexaacrylate and 15 parts of 1,6-hexanediol diacrylate were added to the surface.
Parts by weight, 15 parts by weight of trisacryloyl cyanurate, 10 parts by weight of methyl methacrylate, 2% by weight of cumyl peroxyneodecaate, 3 parts by weight of di-t-butylperoxy-hexahydroterephthalate
spray-painting a scratch-resistant layer-forming material with an average number of acryloyloxy groups of about 4.3% by weight;
Immediately, it was placed in a 200 x 180 mm push-in mold heated to 130°C, and after holding the pressure for 10 minutes, the mold was opened and the molded product was taken out. After polymerizing this molded product at 130℃ for 10 hours in a hot air circulation dryer,
Adhesion, pencil hardness and Taber abrasion tests were conducted in accordance with JISZ1522, JISK5400 and ASTMD-1044. In addition, the steel wool test was carried out using a scratch tester made by Toyo Seiki Seisakusho, with a pressure of 100 g/cm ² against the film surface and a traverse speed of 16 mm/sec.
When reciprocating 100 times with 000 steel wool,
The ratio of the diffuse transmittance and total light transmittance measured according to JISK7105 was defined as the haze value, and the difference in haze value before and after the test was determined. Examples 4 to 7 and Comparative Examples 2 to 3 80 parts by weight of methyl methacrylate syrup containing 8% by weight of polymethyl methacrylate having an average degree of polymerization of about 8000, 20 parts by weight of 2,2-dimethylolpropane dimethacrylate, 1, A mixture of 0.08 g/Kg of 4,8-p-mentadiene, 0.05 g/Kg of cumyl peroxyneodecanoate, and 3 g/Kg of di-t-butyl peroxide was mixed and dissolved into a plate with a thickness of 6 mm.
Two glass plates with a size of 450 x 350 mm are used, and a gasket made of vinyl chloride resin is used, with an interval of 5 mm.
Inject into a cell assembled to a diameter of mm, and preliminarily
The cell was placed in a constant temperature water bath heated to 50℃.
It was polymerized for 2.5 hours and then taken out. The obtained partially crosslinked gel polymer was extracted with acetone in the same manner as in Examples 1 to 3, and the gel fraction was measured, and it was found to be 28%. Examples 1 to 3 of this partially crosslinked gel polymer
It was cut into pieces of the same size and put into the same mold as in Examples 1 to 3, which had been heated to 120°C in advance, and
The mold was opened at 0.5 minutes, 1 minute, 2 minutes, 3 minutes, 4 minutes, and 5 minutes, and the same scratch-resistant layer forming material as in Examples 1 to 3 was applied to the surface of the molded base material during polymerization. Immediately close the mold, hold pressure again, take out the molded product after 20 minutes, polymerize in a hot air circulation dryer at 130℃ for 10 hours, and then apply scratch resistance using the same method as in Examples 1 to 3. The properties and adhesion were examined.
These results are shown in Table 1. The gel fraction of the forming base material was measured using the same mold under the same conditions as the molding, and for the partially crosslinked gel polymer, the remainder of the same cell was used for 0.5 minutes, 1 minute, 2 minutes, and 3 minutes. Immediately immerse it in liquid nitrogen to rapidly cool it, take out a specified amount (10 to 15 g), and take it out every 4 minutes or 5 minutes.Examples 1-
Acetone extraction was performed in the same manner as in 3. Examples 8 to 11 and Comparative Example 4 80 parts by weight of methyl methacrylate trap containing 4% by weight of polymethyl methacrylate with an average degree of polymerization of about 12000, 20 parts by weight of 2,2-dimethylolpropane dimethacrylate, 1,4,8 -p-menthadiene 0.08g/Kg, 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile) 0.03
g/Kg, di-t-butylperoxy-hexahydroterephthalate 0.05g/Kg, 2,2-bis(t-butylperoxy)butane 1g/Kg and di-t-butyl peroxide 3g/Kg mixed and dissolved. The resulting mixture was injected into the same cell as in Examples 1 to 3, and the cell was placed in a thermostatic water bath preheated to 50°C, polymerized for 2.5 hours, and then taken out. The obtained partially crosslinked gel polymer was prepared in Example 1.
Acetone extraction was carried out in the same manner as in 3. The gel fraction was measured and found to be 36%. Next, a scratch-resistant layer-forming material of the same composition as in Example 1 was spray-coated on the inner surface of the cavity of the same mold as in Example 1, which had been preheated to 130°C. After heat polymerization for 10 minutes and 10 minutes, the partially crosslinked gel polymer was charged, the mold was closed, the pressure was kept for 10 minutes, the molded product was taken out, and post-polymerization was carried out at 130° C. for 10 hours.
Scratch resistance and adhesion were measured in the same manner as in Example 1 and are shown in Table 1. The polymerization rate of the scratch-resistant layer is 1
Paint using an applicator to the same film thickness as spray painting on a glass plate of 0.5 mm.
The amount of remaining double bonds is calculated as a percentage by taking it out every minute, 1 minute, 5 minutes, 7 minutes, and 10 minutes and rapidly cooling it, and measuring it from the peak height of the absorption band belonging to C=C that appears around 1620 nm using an infrared method. It was calculated by subtracting the amount of remaining double polymer bonds from 100. The results are shown in Table 1 as the IR method. In addition, the results of the extraction method obtained by the same method as Examples 1 to 3 are also listed in the same table as reference values. Examples 12-13 80 parts by weight of methyl methacrylate syrup containing 4% by weight of polymethyl methacrylate with an average degree of polymerization of about 12,000, 20 parts by weight of 2,2-dimethylolpropane dimethacrylate, 0.04 parts by weight of cumyl peroxyneodecanoate. A mixture obtained by dissolving 2 g/Kg of di-t-butyl peroxide and 2 g/Kg of di-t-butyl peroxide was injected into the same cell as in Example 4, and polymerized in a constant temperature water bath at 50°C for 2 hours. The gel fraction of the crosslinked gel polymer was 74%. Next, Example 8
A scratch-resistant layer-forming material was applied in the same manner as above, polymerized for 1 minute and 7 minutes, respectively, and the above partially crosslinked gel polymer cut into a size of 200 x 180 mm was charged and molded. Thereafter, post-polymerization was carried out at 130° C. for 10 hours, and scratch resistance and adhesion were measured in the same manner as in Example 1. The results are shown in Table 1. Examples 14-15 After polymerizing the scratch-resistant layer forming material of the same formulation as in Example 1 for 1 minute and 7 minutes in the same manner as in Example 12, the partially crosslinked gel polymer of Example 1 was
It was cut into pieces of 180mm x 180mm, charged, and kept under pressure for 20 minutes to obtain a molded product. This molded article was post-polymerized at 130° C. for 10 hours, and the scratch resistance was measured by the same method as in Example 1. The results are shown in Table 1. Examples 16 to 19 and Comparative Example 5 Dipentaerythritol hexaacrylate 15
Parts by weight, 10 parts by weight of 1,6-hexanediol diacrylate, Tris acryloyl cyanurate
22.5 parts by weight, 5 parts by weight of methyl methacrylate, 2% by weight of cumyl peroxyneodecanoate, di-
A scratch-resistant layer-forming material containing 0.2% by weight of t-butylperoxy-hexahydroterephthalate and having an average number of acryloyloxy groups of 3.3 was obtained. This scratch-resistant layer forming material was coated to a thickness of 45 to 50 μm on the surface of the same mold as in Example 1, which had been preheated to 130°C.
After standing for a few minutes, a partially crosslinked gel polymer similar to that in Example 8 was added and heat-molded for 10 minutes.The plate-shaped molded product was then polymerized at 130°C for 10 hours and the scratch resistance was the same as in Example 1. Measured using the same method. The result is the first
Shown in the table. Examples 20-21 and Comparative Example 6 Dipentaerythritol hexaacrylate
A scratch-resistant layer-forming material having an average number of acryloyloxy groups of 5.5 and consisting of 100 parts by weight, 2% by weight of cumyl peroxyneodecanoate, and 0.3% by weight of di-t-butylperoxy-hexahydroterephthalate was heated to 130°C in advance. Heated Example 1 The same mold surface was spray-painted to a thickness of 45 to 50 μm, and 0.5
After standing for 1 minute, 1 minute, and 2 minutes, the same partially crosslinked gel polymer as in Example 8 was added.
Heat molded for 10 minutes. 130 pieces of molded material taken out
Polymerization was carried out at ℃ for 10 hours, and scratch resistance was evaluated as in Example 1.
Measured using the same method as . The results are shown in Table 1. Examples 22 to 23 and Comparative Example 7 Ultraviolet curable scratch-resistant layer forming material manufactured by General Aniline & Film Company on polyethylene terephthalate film
GAFGUADE−233 with applicator 45~
The coating was applied to a thickness of 50μm, and two 50W chemical lamps were placed in parallel to illuminate the painted surface from a height of 5cm.
The film, which had been irradiated for 1, 8 and 10 minutes, was brought into contact with a partially crosslinked gel-like polymer similar to that obtained in Example 2 on the coated side, placed inside the mold used in Example 1, and heated at 120°C. After holding pressure for 20 minutes and curing,
The sample was taken out and subjected to post-polymerization at 130°C for 10 hours, and its scratch resistance was examined in the same manner as in Example 1. The results are shown in Table 1. Comparative Example 8 The partially crosslinked gel polymer of Example 8 was heated to 130°C in advance.
200 x 180 mm in the same mold as Example 1 heated to
It was cut into pieces of size, filled, held under pressure for 10 minutes, then taken out, and polymerized at 130°C for 10 hours. The abrasion resistance of the molded product was examined in the same manner as in Example 1, and the results are shown in Table 1. Example 24 As a scratch-resistant layer forming material, 75 parts by weight of dipentaerythritol hexacrylate, 10 parts by weight of trisacryloyl cyanurate, 15 parts by weight of 1,6-hexanediol diacrylate, and 5 parts by weight of methyl methacrylate were mixed with 2-hydrochloride. Oxy-
2-Methyl-phenyl-propan-1-one
It was obtained by adding 0.5% by weight. This scratch-resistant layer forming material was spray-coated to a thickness of 25 to 30 μm in the same mold as in Example 1, which had been preheated to 130°C.
After irradiating for 5 seconds with a high-pressure mercury lamp with an output of 80 W/cm, the forming substrate was put in, the pressure was held for 10 minutes, the molded article was taken out, and post-polymerization was carried out at 130° C. for 10 hours. The abrasion resistance of the molded product was examined in the same manner as in Example 1, and the results are shown in Table 1. Example 25 90 parts by weight of methyl methacrylate syrup containing 8% by weight of polymethyl methacrylate with an average degree of polymerization of about 20,000, 10 parts by weight of 2,2-dimethylolpropane dimethacrylate, 1,4,8-p- Menthadiene 0.1g/Kg, 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile) 0.03
A mixture of 0.5 g/Kg of di-t-butyl peroxy-hexahydroterephthalate and 3 g/Kg of di-t-butyl peroxide was polymerized by the method of Example 1 to obtain a gel fraction of 36%. A partially crosslinked gel polymer was obtained. Next, 40 parts by weight of caprolactam-modified dipentaerythritol hexaacrylate (Nippon Kayaku DPCA-20), 40 parts by weight of trisacryloyl cyanurate, 1. A scratch-resistant layer forming material consisting of 20 parts by weight of 6-hexadiol diacrylate, 20 parts by weight of methyl methacrylate, 1.0% by weight of benzoyl peroxide, and 4.0% by weight of t-butylperoxyisopropyl carbonate was spray-painted and thermally polymerized for 45 seconds. After that,
After adding the above partially crosslinked gel polymer and holding the pressure for 10 minutes, the molded product was taken out and placed in a hot air circulation dryer.
Post-polymerization was carried out at 120°C for 10 hours. The scratch resistance and adhesion were measured in the same manner as in Example 1, and the polymerization rate of the scratch-resistant layer forming material was measured in the same manner as in Example 8.
Shown in the table. Example 26 95 parts by weight of methyl methacrylate syrup containing 8 parts by weight of polymethyl methacrylate having an average degree of polymerization of about 20,000, 5 parts by weight of 2,2-dimethylolpropane dimethacrylate, 1,4,8-p- Menthadiene 0.08g/Kg, walnut peroxyneodecanoate 0.05g/Kg, dibutylperoxyhexahydroterephrate 0.5g/Kg, 2,2'-bis(t-butylperoxy)butane 1.0g/Kg and A mixture of 3 g/kg of di-t-butylside mixed and dissolved was polymerized for 2 hours and 30 minutes in the same manner as in Example 1 to obtain a partially crosslinked gel polymer with a gel fraction of 25%. Next, a scratch-resistant layer-forming material having the same formulation as in Example 25 was spray-coated onto the same mold as in Example 1, which had been preheated to 135°C, and after thermal polymerization for 45 seconds, the partially crosslinked gel-like After charging the polymer and holding the pressure for 10 minutes, the mold was lowered to 100°C, the molded product was taken out, and polymerization was carried out at 115°C for 10 hours in a hot air circulation dryer. Scratch resistance and adhesion were as in Example 1,
The polymerization rates of the scratch-resistant layer forming materials were measured in the same manner as in Example 8, and are shown in Table 1. Example 27 75 parts by weight of methyl methacrylate syrup containing 8% by weight of polymethyl methacrylate with an average degree of polymerization of about 20,000, 25 parts by weight of 2,2-dimethylolpropane dimethacrylate, 1,4,8-p- Menthadiene 0.1g/Kg, 2,2'-Asobis(4-methoxy-2,4-dimethylvaleronitrile) 0.03
g/Kg, di-t-butylperoxy-hexahydroterephthalate 0.5g/Kg, 2,2-bis(t-butylperoxy)butane 1g/Kg, di-
A mixture of 3 g/kg of t-butyl peroxide mixed and dissolved was polymerized in the same manner as in Example 1 to obtain a partially crosslinked gel polymer with a gel fraction of 34%. next,
Into the same mold as in Example 1, which was preheated to 135°C,
The same scratch-resistant layer-forming material as in Example 25 was spray-coated and thermally polymerized for 43 seconds, then the mold was opened and the molded product was taken out, followed by post-polymerization at 130° C. for 10 hours. The scratch resistance and adhesion were measured in the same manner as in Example 1, and the polymerization rate of the scratch-resistant layer forming material was measured in the same manner as in Example 8, and the results are shown in Table 1. Example 28 The partially crosslinked gel polymer with a gel fraction of 36% obtained in Example 25 was cut into the same area as the projected area of the mold,
The same scratch-resistant layer-forming material as in Example 25 was poured into the same mold as in Example 1, which had been heated to 130°C in advance, and the mold was opened after holding the pressure for 80 seconds. was spray painted. Immediately, the mold was closed and pressure was maintained again, and after 10 minutes the molded product was taken out and polymerized at 130°C for 10 hours in a hot air circulation dryer. The scratch resistance and adhesion were measured in the same manner as in Example 1, and the gel fraction of the molded base material was measured in the same manner as in Example 4, and the results are shown in Table 1. Comparative Example 9 A partially crosslinked gel polymer obtained in the same manner as in Example 8 was charged into the cavity of the same mold as in Example 1, which had been preheated to 130°C, and the mold was closed.
After holding pressure for 10 minutes, the molded part was removed and a power of 80
High-pressure mercury lamp consisting of watts/cm (main wavelength 365nm)
irradiation amount of light 8.5×10 ⁴ (unit: watts/second/m ² )
After irradiation with 130 μm, the same scratch-resistant layer forming material as in Example 1 was spray-painted to a thickness of 10 to 20 μm.
Post-polymerization was carried out at ℃ for 10 hours, and at the same time the polymerization was solidified to form a scratch-resistant film. The result is the first
Shown in the table. Example 29 The molded products obtained in Example 21, Example 9, and Comparative Example 9 and commercially available scratch-resistant plates were subjected to an accelerated ultraviolet exposure test (Toyo Seiki UVCON UV70°C).
Example 1
Using the same method as above, we determined the difference in haze value by the steel wool test and plotted the difference in haze value as a function of the accelerated exposure time to ultraviolet light, as shown in the drawing.

【table】

[Table] From the above examples, Table 1, and Figure 1, (1) Example 1 focusing on the gel fraction of the molding base material
From ~7, 27 and Comparative Examples 1 to 3, the gelation fraction
If it exceeds 10% or 96%, deformation of the molded product and poor adhesion occur, but in all other examples, molded products with extremely good adhesion and scratch resistance can be obtained at the same time as molding. (2) From Examples 8 to 26 and Comparative Examples 4 to 7, which focused on the number x of acryloyl groups and the polymerization rate y of the scratch-resistant layer forming material, crosslinking having at least two acryloyloxy groups per molecule Adhesiveness is obtained when a monomer whose main component is a polymerizable compound or a partial polymer thereof is used, and the number x of acryloyloxy groups and the polymerization rate y (%) of the scratch-resistant layer forming material satisfy the formula or A molded product with extremely good scratch resistance can be obtained at the same time as molding. (3) Regarding the scratch resistance after the weather resistance test, as shown in Figure 1, compared to commercially available durability-imparting plates or molded products with a scratch-resistant film added afterwards, In the case of this example, the decrease in scratch resistance with respect to the exposure time to ultraviolet rays was halved. It can be seen that a molded article with excellent heat resistance and extremely good adhesion and scratch resistance was obtained. (Effects of the Invention) As described above, the present invention provides that the scratch-resistant layer forming material has a molecular weight of 150 or more and at least 2 per molecule.
The material consists of a monomer whose main component is a crosslinked polymerizable compound having (meth)acryloyloxy groups or a partial polymer thereof, and the number x of (meth)acryloyloxy groups and the polymerization rate y of the scratch-resistant layer forming material. (%)
Since the scratch-resistant layer is formed on the surface of the heat-resistant base material at the same time as the molded base material, the adhesion between the molded base material and the scratch-resistant layer is extremely good, and the scratch-resistant layer is excellent. , it is possible to obtain a highly heat-resistant methacrylic warp resin molding with little change in scratch resistance due to exposure. Moreover, simultaneous molding simplifies the process, which is advantageous. Therefore, the molded article obtained by the present invention can be used in fields where performance such as weather resistance, scratch resistance, and heat resistance is required, such as automobile headlamp lenses, lamp covers, motorcycle meter covers,
Can be used for solar water heater covers, etc.

[Brief explanation of the drawing]

FIG. 1 is a graph showing the difference in haze value determined by ultraviolet exposure time and steel wool test for molded articles obtained according to the present invention, articles in which a scratch-resistant film is later formed on the molded article, and commercially available scratch-resistant plates. It is.

Claims (1)

[Scope of Claims] 1 (A) (a) A cross-linked polymerizable compound in which the scratch-resistant layer forming material has a molecular weight of 150 or more and at least two (meth)acryloyloxy groups per molecule, (b)
(meth)acryloyl of the crosslinking polymerizable compound selected from the group consisting of a mixture with other polymerizable monomers containing 30% by weight or more and (c) a partial polymer thereof; Number of oxy groups x and polymerization rate y (%) of the scratch-resistant layer forming material
and a scratch-resistant layer forming material that satisfies the following formula or y≦70 (2≦x≦3.5) () y≦−7.5x ² +52x−18 (3.5<x≦6) (); () A resin raw material selected from the group consisting of an alkyl methacrylate monomer, a mixture with an α,β-ethylenically unsaturated monomer containing alkyl methacrylate as a main component, and a syrup containing the polymer; Consisting of an acrylic partially crosslinked gel polymer obtained by mixing 3 to 30 parts by weight of a crosslinking agent to 100 parts by weight of the resin raw material, partially polymerizing the mixture, and stopping the polymerization at a gel fraction of 15 to 95%. A methacrylic resin molded article made of a crosslinked polymer whose surface is at least partially covered with an abrasion-resistant layer obtained by simultaneous polymerization under conditions that impart a desired shape to a molding base material. 2. The molded article according to claim 1, wherein the alkyl group of the alkyl methacrylate has 1 to 4 carbon atoms. 3. The molded article according to claim 2, wherein the alkyl methacrylate is methyl methacrylate. 4. Claim 1, wherein the scratch-resistant layer forming material has a (meth)acryloyloxy group number of 2.5 to 5.5.
The molded article according to any one of Items 1 to 3. 5 (A) (a) A crosslinked polymerizable compound in which the scratch-resistant layer forming material has a molecular weight of 150 or more and at least two (meth)acryloyloxy groups per molecule, (b)
(meth)acryloyl of the crosslinking polymerizable compound selected from the group consisting of a mixture with other polymerizable monomers containing 30% by weight or more and (c) a partial polymer thereof; Number of oxy groups x and polymerization rate y (%) of the scratch-resistant layer forming material
and a scratch-resistant layer forming material that satisfies the following formula or y≦70 (2≦x≦3.5) () y≦−7.5x ² +52x−18 (3.5<x≦6) (); () A resin raw material selected from the group consisting of an alkyl methacrylate monomer, a mixture with an α,β-ethylenically unsaturated monomer containing alkyl methacrylate as a main component, and a syrup containing the polymer; Consisting of an acrylic partially crosslinked gel polymer obtained by mixing 3 to 30 parts by weight of a crosslinking agent to 100 parts by weight of the resin raw material, partially polymerizing the mixture, and stopping the polymerization at a gel fraction of 15 to 95%. Polymerization is simultaneously carried out under conditions that impart the desired shape by contacting the molding base material to obtain a molded article made of a crosslinked polymer whose surface is at least partially covered with an abrasion-resistant layer. A method for manufacturing a methacrylic resin molded article.