JP3277606B2 - Method for producing scratch-resistant non-glare synthetic resin plate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a scratch-resistant, non-glare synthetic resin plate.

[0002]

2. Description of the Related Art In a display of a personal computer or a word processor, the reflected light on the surface makes it difficult to see the screen, which makes the user uncomfortable and reduces the work efficiency. Therefore, what is called a non-glare property in which the reflected light is suppressed, and in addition, a durable one that is hardly scratched on the surface is desired, and a transparent synthetic resin plate corresponding to this is desired.

[0003] As a method for producing such a synthetic resin molded article having non-glare properties and scratch resistance, a raw material for forming a film having non-glare properties and scratch resistance is cured after curing of the synthetic resin substrate. A method has been proposed in which the composition is applied and cured to impart non-glare properties and scratch resistance.
For example, Japanese Patent Application Laid-Open No. 56-84729 discloses a method in which a film forming raw material containing a silicon-based compound as a main raw material is applied.
No. 156832 and the like disclose a method in which a film-forming raw material containing a compound having a plurality of acryloyloxy groups in a molecule as a main raw material is applied. In addition, JP-A-61-76328 and JP-A-64-46702 disclose an ultraviolet-curable scratch-resistant film-forming raw material liquid between a mold having fine irregularities on the surface and a synthetic resin substrate. A method is disclosed in which the raw material is polymerized and hardened in a state where the raw material is in a heated state.

[0004]

In a method of applying a scratch-resistant coating material in which silica particles are dispersed to a synthetic resin plate,
The surface irregularities are locally disturbed during coating and curing of the film forming raw material, which impairs the commercial value, and it is difficult to obtain reproducibility of the degree of surface irregularities. Further, in the method of polymerizing and curing an ultraviolet-curable scratch-resistant film-forming raw material liquid in a state where the raw material liquid is interposed between a synthetic resin material and a mold having fine irregularities on the surface, the mold and the synthetic resin substrate When a UV-curable scratch-resistant film-forming raw material liquid is interposed in the varnish, surface defects are likely to occur due to the entrapment of air bubbles. As a countermeasure, it is necessary to warp or pressurize the synthetic resin base material, and the apparatus becomes large-scale. Furthermore, if the synthetic resin substrate has a crosslinked structure for the purpose of improving heat resistance and strength, the adhesion between the scratch-resistant film and the substrate may be insufficient.

[0005] Therefore, the present invention provides a synthetic resin plate having a uniform non-glare property with a uniform surface unevenness, excellent scratch resistance, and firmly adhering a film exhibiting scratch resistance.

[0006]

According to the present invention, an ultraviolet curable liquid is applied to an inner surface of a mold having an inner surface on which fine irregularities are formed, and the liquid is cured by irradiating it with ultraviolet light. Forming a scratch-resistant film in the mold,
Subsequently, an ethylenically unsaturated monofunctional monomer in the template ,
This is a method for producing a scratch-resistant non-glare synthetic resin plate in which a synthetic resin raw material liquid comprising an ethylenically unsaturated polyfunctional monomer and a radical polymerization initiator is injected and polymerized.

[0007] The mold having an inner surface with fine irregularities used in the present invention is a mold using a plate material with fine irregularities formed on at least one surface by a known method such as sand blasting or chemical etching. This is a mold for so-called casting polymerization, which is made up of one plate material and a gasket.

[0008] The form of the fine unevenness is not particularly limited and can be appropriately selected depending on the purpose.
The value of 10-point average roughness measured according to -B0601 is 0.1 to 50 µm.

The material of the plate is not particularly limited as long as it can process fine irregularities on the surface.
For example, there are inorganic glass, stainless steel, nickel-chromium-plated metal, and aluminum.

As the ultraviolet-curable liquid used in the present invention, known liquids may be used. For example, Japanese Patent Publication No. 54-14617, Japanese Patent Publication No. 54-14618, Japanese Patent Publication No. 4-35488, What is described in JP-A-56-139507, etc. can be applied.
This is a so-called UV-curable hard coat agent mainly composed of a mixture of a photopolymerizable oligomer, a monomer, a photopolymerization initiator and, if necessary, an organic solvent.

Examples of the photopolymerizable oligomer include epoxy acrylate, urethane acrylate, unsaturated polyester, polyester acrylate, polyether acrylate, vinyl acrylate and polyenthiol. Among them, urethane acrylate-based ones which have less polymerization inhibition by oxygen and have good releasability from a template are preferable.

As the monomers, various (meth) acrylates having photopolymerizability are suitable.

Examples of photopolymerization initiators include cleavable polymerization initiators such as benzoin, benzoin ethers, 1-hydroxycyclohexyl phenyl ketone, benzyldimethyl ketal, and acylphosphine oxide; benzophenone,
And hydrogen abstraction type photopolymerization initiators such as Michler's ketone and thioxanthones. If necessary, a photosensitizer may be used in combination. The photopolymerization initiator is used in an amount of 0.1 to 10 parts by weight, preferably 1 to 5 parts by weight, based on 100 parts by weight of the photopolymerizable oligomer and monomers.

As a method of applying an ultraviolet curable liquid to a plate material having a surface on which fine irregularities are formed, there are spin coating, bar coating, roll coating, spray coating, brush coating, and the like.

The thickness of the coating film of the ultraviolet-curable liquid depends on the thickness of the synthetic resin plate, but is preferably about 3 to 50 μm from the balance between scratch resistance and mechanical strength.

The ultraviolet irradiation of the present invention may be a general ultraviolet irradiator such as a high-pressure mercury lamp, a metal halide lamp, a xenon lamp, a krypton arc lamp, a xenon flash lamp, a flash UV lamp, and is not particularly limited.

Irradiation with ultraviolet light may be carried out to such an extent that the surface of the coating film of the ultraviolet curable liquid does not become sticky, and need not be completely cured. The amount of UV irradiation is generally 100 ~
It is about 5000 mJ / cm ² . Specifically, this is determined by the intensity of the light source used, the thickness of the coating film, the type and concentration of the photopolymerization initiator, and the like, so that conditions suitable for several trials can be set.

The raw material liquid of the present invention comprises an ethylenically unsaturated monomer and a radical polymerization initiator. Furthermore, what is called a syrup in which a polymer soluble in the monomers is dissolved may be used . Not monofunctional only to the ethylenically unsaturated monomer, Ru also included those polyfunctional.

Examples of the ethylenically unsaturated monofunctional monomer include methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, isopropyl (meth) acrylate, and bornyl (meth) acrylate. , (Meta)
Aliphatic alcohols having 1 to 25 carbon atoms such as cyclohexyl acrylate, dicyclopentanyl (meth) acrylate,
(Meth) acrylic acid esters of alicyclic alcohols; aromatic vinyl compounds such as styrene; vinyl esters such as vinyl acetate; Above all, monomers mainly composed of methyl methacrylate or styrene are generally used from the viewpoint of availability, polymerization curability, transparency and strength of the polymer.

The ethylenically unsaturated polyfunctional monomers include:
Ethylene glycols such as ethylene glycol di (meth) acrylate and tetraethylene glycol di (meth) acrylate, or oligomers thereof, in which both terminal hydroxyl groups are esterified with (meth) acrylic acid; neopentyl glycol di (meth) acrylate, hexane Hydroxyl groups of other dihydric alcohols such as diol di (meth) acrylate esterified with (meth) acrylic acid; bisphenol A or an alkylene oxide adduct of bisphenol A or a halogen-substituted product thereof with hydrogen at both terminals ( Esterified with (meth) acrylic acid; esterified with a polyhydric alcohol such as trimethylolpropane or pentaerythritol with (meth) acrylic acid;
And glycidyl (meth) acrylates of dihydric alcohols or polyhydric alcohols obtained by ring-opening addition of glycidyl groups; allyl (meth) acrylate, diallyl phthalate, diallyl maleate, divinylbenzene and the like. The polyfunctional monomer improves the mechanical strength and heat resistance of the obtained synthetic resin plate.

Examples of the radical polymerization initiator include diacyl peroxides such as benzoyl peroxide, lauroyl peroxide and disuccinic acid peroxide; di-t-butyl peroxide, t-butyl cumyl peroxide and dicumyl peroxide. Dialkyl peroxides; peroxyesters such as t-butylperoxyacetate, t-butylperoxypivalate, t-butylperoxybenzoate, t-butylmaleic acid hemiperester; t-butyl hydroperoxide, methyl ethyl ketone peroxide Organic peroxides such as ketone peroxides and 2,2-
Azobisisobutyronitrile, 2,2-azobis (2,
Azo compounds such as 4-dimethylvaleronitrile).

Such a polymerization initiator is contained in the raw material solution in an amount of 0.01%.
Use ~ 5% by weight.

When particularly rapid polymerization is desired, the peroxide-based radical polymerization initiator is combined with a polymerization accelerator,
As the polymerization accelerator, a so-called redox initiator containing a reducing substance as a main component may be used.

The reducing substance may be a known substance which forms redox, and furthermore, a sulfur compound having a valence of 4 or less such as mercaptans such as glycol dimercaptoacetate and 2-mercaptoethanol acetate; triphenyl phosphite; , 10, -Dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and the like.

Such a reducing substance is contained in the raw material solution in an amount of 0.05%.
Use up to 5% by weight.

Further, as an auxiliary component, a hydrogen halide of a heavy metal compound and an amine, or a quaternary ammonium halide is optionally used.

Examples of the heavy metal compound include compounds of at least one metal selected from iron, copper and cobalt, which are soluble in the monomers. For example, naphthenates and acetylacetone complex salts of these metals can be mentioned. Such a heavy metal compound is converted into a metal, and 0.05 to
Use 10 ppm.

Examples of the amine hydrogen halide or quaternary ammonium halide include hydrochlorides of amines such as N, N-dimethyloctylamine and phenethyldibutylamine; and tetramethylammonium chloride and trioctylmethylammonium chloride. Can be These compounds are used in an amount of 0.01 to 1% by weight in the raw material liquid.

Further, various additives such as an acrylic rubber, a stabilizer, a plasticizer, a polymerization regulator, a flame retardant, a filler, a dye and a pigment may be added to the raw material liquid mixture as needed.

As a method of injecting the raw material liquid into the mold, any method may be used as long as the raw material liquid can be filled in the mold. For example, there is a method of pouring the mold into a horizontally opened mold and then closing the mold, a method of press-fitting from a part of a mating portion of a closed mold which is closed vertically or slightly inclined, and the like.

The polymerization of the raw material liquid in the mold is carried out by heating the mold and raising the temperature to a temperature suitable for the polymerization initiator using the raw material liquid.
Polymerize and cure. As the heating method, air oven,
There are a method using a warm bath, a method using a hot press such as a hot press, and a method using far infrared rays or microwaves.

The polymerization curing time is desirably as small as possible for the unreacted monomer, and is about 5 minutes to 10 hours, depending on the type of polymerization initiator used and the thickness of the synthetic resin plate. In addition, during polymerization hardening, to prevent warping and deformation of the molded article due to heat and to compensate for volume shrinkage due to polymerization, 0.01-5 kg
The pressure may be about / cm ² .

After the completion of the polymerization and curing, the mold is opened by cooling, and a synthetic resin plate having scratch resistance and non-glare properties is taken out.

[0034]

According to the method of the present invention, a synthetic resin plate having a scratch-resistant and uniform non-glare film firmly can be obtained.

[0035]

The following examples are provided to further illustrate the method of the present invention, but the invention is not limited thereto. In addition, evaluation of the synthetic resin molded article having the obtained scratch-resistant film is performed by the following method.・ Adhesion: 100 cross hatches at 1 mm intervals
Performed by the so-called cross-cut test that performs cellophane peeling,
The percentage of the number of cross hatches that did not peel was indicated by%. Scratch resistance: # 000 on the surface of the test piece with a load of 1 kg / cm ²
The steel wool was pulled while being pressed, and the presence or absence of scratches was examined. Surface defects: The presence or absence of bubbles was visually inspected. The presence was evaluated as x, and the absence was evaluated as ○.・ Surface roughness: 10 using a surface roughness profile measuring instrument (Surfcom 550A manufactured by Tokyo Seimitsu) in accordance with JIS B0601 0601.
It was shown by point average roughness. Non-glare property: The image clarity of the reflected light at 45 ° was measured using an optical comb having a width of 2 mm with an image clarity measuring instrument (ICM-1DP manufactured by Suga Test Instruments) in accordance with JIS K 7105-1981.

Example 1 300 × 350 having irregularities with a 10-point average roughness of 3 μm
× 5mm glass plate and 300 × 350 × 5mm with smooth surface
3.5 g of a UV curing liquid Koeihard T-65 (urethane acrylate-based hard coating agent manufactured by Koei Chemical Industry Co., Ltd.) was applied on each of the above glass plates with a bar coater, and air-dried for 5 minutes, and then 120 w / cm metal halide. The lamp was irradiated at 1000 mJ / cm ² for about 10 seconds from a distance of 200 mm to obtain a scratch-resistant film having a thickness of 6 μm. The two glass sheets were opposed to each other so that the surface coating was on the inside, and a cell was assembled with a soft vinyl chloride resin gasket sandwiched so that the interval was 1 mm. 0.1 parts by weight of t-butylperoxy-2-ethylhexanoate and methyl methacrylate 8 were added to the cell.
A syrup obtained by mixing 20 parts by weight of an acrylic rubber-containing methacrylic resin (DR manufactured by Rohm and Haas Co.) and 5 parts by weight of neopentyl glycol dimethacrylate was poured into 0 part by weight, and the mixture was heated at 80 ° C. in an air oven for 1 hour and then at 130 ° C.
For 1 hour. After cooling, the cell was opened to obtain a resin plate having a scratch-resistant non-glare film. Table 1 shows the evaluation results.

Example 2 Example 1 was repeated except that a glass plate having irregularities with a 10-point average roughness of 0.3 μm was used instead of the glass plate with irregularities with a 10-point average roughness of 3 μm in Example 1. A cell was assembled in the same manner as described above. T-butyl peroxy-2- was added to the cell.
Methyl methacrylate partial polymer containing 0.6 parts by weight of ethyl hexanoate, 0.06 parts by weight of dimethyloctyl ammonium chloride, 0.6 parts by weight of glycol dimercaptoacetate, and 6 ppm of copper naphthenate (copper content: 10% by weight) A syrup containing 90 parts by weight and 10 parts by weight of tetraethylene glycol dimethacrylate was injected.
20 minutes in an air oven at 0 ° C, then 1 hour at 120 ° C
Heat polymerization was performed. After cooling, the cell was opened to obtain a resin plate having a scratch-resistant non-glare film. Table 1 shows the evaluation results.

Comparative Example 1 A glass plate having irregularities with an average roughness of 10 μm of 3 μm (30
(0 × 350 × 5 mm), 3 g of the same ultraviolet curing liquid as used in Example 1 was applied using a bar coater. Thickness 1.5
A crosslinked methacrylic resin plate containing 5% by weight of neopentyl glycol dimethacrylate having a thickness of 5 mm was gradually overlapped and adhered from one end of the glass plate. Then 1 from the glass plate side
A 20 w / cm metal halide lamp was irradiated at 1000 mJ / cm ² for about 10 seconds from a distance of 200 mm to peel off from the glass plate to obtain a resin plate having a 6 μm-thick scratch-resistant non-glare film. Table 1 shows the evaluation results.

Comparative Example 2 The procedure of Comparative Example 1 was repeated, except that a glass plate having irregularities having a 10-point average roughness of 0.3 μm was used instead of the glass plate having irregularities having a 10-point average roughness of 3 μm. went. Table 1 shows the evaluation results.

[0040]

[Table 1]

Continuation of the front page (56) References JP-A-61-108520 (JP, A) JP-A-50-110449 (JP, A) JP-A-6-87129 (JP, A) JP-A-60-9718 (JP) , A) JP-A-60-76328 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B29C 39/10-39/12 B29C 39/22-39/26 B29C 33/42 B32B 27/30 C08F 2/00 C08F 220/12-220/20 C08J 7/04

Claims (1)

(57) [Claims] 1. An abrasion-resistant coating is applied to an inner surface of a mold having an inner surface on which fine irregularities are formed by applying an ultraviolet curable liquid and irradiating it with ultraviolet light to cure the liquid. to form, followed by ethylenically unsaturated monofunctional monomer in its mold, ethylenically unsaturated polyfunctional monomer
A method for producing a scratch-resistant non-glare synthetic resin plate, which comprises injecting a synthetic resin raw material liquid comprising a polymer and a radical polymerization initiator and polymerizing the same.