JPS6173709A - Production of synthetic resin molding having surface excellent in scratch resistance and antistaticity - Google Patents

Abstract

PURPOSE:To obtain a synthetic resin molding having a surface excellent in scratch resistance and antistaticity, by curing, by polymerization, a specified crosslinkable curable resin material placed between an inorganic glass or metallic mold and a synthetic resin molding. CONSTITUTION:A crosslinkable curable resin material comprising 90.99.8wt% polymerizable compound (A) having at elast two (meth)acryloyloxy groups in the molecule and 0.2-10wt% polymerizable acidic phosphate of formula I is cured by polymerization between an inorganic glass or metallic mold and a synthetic resin molding. This synthetic resin molding having an integrally formed crosslinked cured film on the surface is separated from the mold. In the formulae, R1 is H or methyl, R2 is H or formula II, R3 is H or methyl and m and n are each 1-5. As the compounds of formula I, (meth) acryloxypropyl phosphate, etc., are particularly desirable because they can exhibit an excellent antistatic effect at a relatively small amount of use.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing a synthetic resin molded article having a surface with excellent scratch resistance and antistatic properties.

[Prior art]

Currently, many synthetic resin molded products are on the market, and although they have many excellent properties, they generally have low surface hardness (
Since the resistance to abrasion is low, the surface of the product is easily scratched during processing or transportation, which not only damages the product value, but also prevents dust and chips from adhering to the surface of the plastic product during use. When removing dirt such as dirt with a cloth, etc., it is easy to cause wiping scratches or scratches, and it is also easy to get abrasion scratches due to collision with other objects, and in extreme cases, these scratches can cause the optical properties to be lost. It had a fatal flaw in that it was completely unusable.

To address this problem, several methods have already been used industrially to form a scratch-resistant film on the surface of synthetic resin molded products, and the problem has been practically solved in many application fields. ing.

However, in applications such as instrument dials and see-through panels, there is an extremely strong demand for synthetic resin molded products that have not only scratch resistance but also antistatic properties. However, with the prior art, a synthetic resin molded product having both scratch resistance and antistatic ability that satisfies market requirements has not been obtained industrially.

That is, for example, in Japanese Patent Application Laid-open No. 55-86848,
Three or more (meth)acryloyloxy groups in one molecule (
Irradiation of active energy rays in air consisting of a compound having an acryloyloxy group or a methacryloyloxy group (the same shall apply hereinafter), a polymerizable acidic phosphate ester having a (meth)acryloyloxy group, and an ethanolamine-based compound. discloses a coating composition that forms a film having both scratch resistance and antistatic properties.

However, the above method has the problem that when a large amount of compound is added in order to impart sufficient antistatic ability, cloudiness tends to occur due to what is thought to have bleed onto the surface. , its improvement is desired.

[Problem that the invention seeks to solve]

Under the current situation as described above, as a result of intensive studies aimed at providing synthetic resin molded products with sufficient scratch resistance and antistatic properties, we have developed a specific polymerizable compound and a specific polymerizable acidic phosphate ester. By forming a cured film on the surface of a synthetic resin molded product using a cross-linked curable resin material consisting of a mold made of glass or metal,
The inventors have discovered that a synthetic resin molded article that meets the above-mentioned objectives can be obtained, and have thus arrived at the present invention.

[Means for solving problems]

The method for manufacturing a synthetic resin molded product having a surface with excellent scratch resistance and antistatic properties according to the present invention is characterized in that between a mold made of inorganic glass or solid steel and a synthetic resin molded product, at least two Polymerizable compound (A) having an acryloyloxy group and/or a methacryloyloxy group
90 to 99.8% by weight and the following general formula [I] (wherein,
R1 is hydrogen or a methyl group, R2 is hydrogen or a methyl group, m and n are integers of 1 to 5) (B) 0.2 to 10
This method is characterized by polymerizing and curing a cross-linked curable resin material consisting of % by weight, and then separating the synthetic resin molded article with a cross-linked cured film integrally formed on the surface from the mold.

The most important feature of the present invention is that on the surface of the synthetic resin molded product,
When providing a cured film with excellent scratch resistance and antistatic properties, the above specific mold and specific crosslinked curable resin material are used in combination.

Therefore, the synthetic resin molded product obtained by the present invention is
It has significantly better antistatic properties than synthetic resin molded products produced using similar crosslinked curable resin material compositions in a gas such as air or in contact with a polymer film.

For this reason, in the method of the present invention, the amount of polymerizable acidic phosphate ester added is small compared to other methods, and other defects in surface properties are less likely to occur.

Specific examples of the mold used in the present invention include inorganic glass such as tempered glass, stainless steel, aluminum, and metal such as chrome plating. Glass and metal mold surfaces are generally mirror surfaces, but in some cases, surfaces with minute irregularities and anti-glare treatment may also be used depending on the purpose.

A small amount of (
The polymerizable compound (A) both having two acryloyloxy groups and/or methacryloyloxy groups is an esterified product obtained from a polyhydric alcohol and (meth)acrylic acid or a derivative thereof, or a polyhydric alcohol and a polyhydric alcohol. Specific examples include esterified products obtained from carboxylic acid and (meth)acrylic acid or derivatives thereof. Examples of polyhydric alcohols include ethylene glycol, diethylene glycol, and triethylene glycol.

Tetodiethylene glycol, a polyethylene glycol having an average molecular weight of about 300 to about 1000.

Propylene glycol, dipropylene glycol, 1,
3-propanediol, 1,3-butanediol, 2,
3-butanediol, 1,4-butanediol, 1,5
-bentanediol, 1,6-hexanediol, neopentyl glycol (2゜2-dimethyl-1,3-propanediol), 2-ethyl-1,3-hexanediol, 2,2'-thiodietanol, 1 , 4-cyclohexane dimetatool, other dihydric alcohols, trimethylolpropane (1,1,1-trimethylolpropane), pentaglycerol (1,1,1-) IJ
methylolethane), glycerol, pentaerythritol (2,2-bishydroxymethyl-1°3-propanediol), diglycerol, dipentaglycerol, etc.

Particularly preferred compounds obtained from these and (meth)acrylic acid include diprolene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, and polyethylene glycol di(meth)acrylate. Acrylate.

1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, trimethylolpropane tri(meth)acrylate, trimethylolethane tri(meth)acrylate.

Examples include pentaerythritol tetra(meth)acrylate, cypentacrycerol penta(meth)acrylate, dipentaglycerol hexa(meth)acrylate, and the like.

Additionally, polymerizable compounds obtained from polyhydric alcohols, polyhydric carboxylic acids, and (meth)acrylic acids or their derivatives are basically the hydroxyl groups of polyhydric alcohols, polyhydric carboxylic acids, and (meth)acrylic acids. It is obtained by reacting a mixture such that both carboxyl groups are ultimately equivalent.

Preferred compounds include a polyhydric alcohol, a dihydric alcohol, a trihydric alcohol, or a mixture of a dihydric alcohol and a trihydric alcohol, and a dihydric carboxylic acid as the polyhydric carboxylic acid. Examples include esterified products. When a mixture of trihydric alcohol and dihydric alcohol is used, the molar ratio of trihydric alcohol to dihydric alcohol can be selected as desired. Also, 2
The molar ratio of divalent carboxylic acid and (meth)acrylic acid is preferably such that the equivalent ratio of the carboxyl group of the divalent carboxylic acid to the carboxyl group of (meth)acrylic acid is in the range of 2:1 to O:1. . If the divalent carboxylic acid is in excess of the above range, the viscosity of the resulting ester becomes too high, making it difficult to form a coating film.

Examples of divalent carboxylic acids include conohydric acid.

Aliphatic dicarboxylic acids such as adipic acid and sebacic acid; alicyclic dicarboxylic acids such as tetrahydrophthalic acid and 3,6-nintomethylenetetrahydrophthalic acid; aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, and terephthalic acid;
Thiodiglycolic acid, thiodivaleric acid, diglycolic acid or maleic acid, fumaric acid, itaconic acid, etc. or their chlorides, anhydrides and esters can be used.

The polymerizable acidic phosphate ester (B) represented by the general formula [1] constituting the crosslinked curable resin material of the present invention includes (
meth) acryloxyethyl phosphate, di(meth)
Examples include acryloxyethyl phosphate, (meth)acryloxypropyl phosphate, di(meth)acryloxypropyl phosphate, (meth)acryloxybutyl phosphate, and di(meth)acryloxybutyl phosphate. Among these, (meth)acryloxyethyl phosphate and (meth)acryloxypropyl phosphate contain two OH groups in the molecule.

(Meth)acryloxybutyl phosphate is particularly preferred since it exhibits excellent antistatic properties even when added in a relatively small amount.

In the present invention, a polymerizable compound (A) having at least two acryloyloxy groups and/or methacryloyloxy groups in the molecule and a polymerizable acidic phosphate ester (
The mixing ratio with B) is 90 to 99% of the polymerizable compound (A).
．． Polymerizable acidic phosphate ester (B) 0 to 8% by weight
．． It is 2 to 10% by weight.

If the amount of polymerizable acidic phosphate ester (B) added is less than 0.2% by weight, the resulting film surface will not have sufficient antistatic properties, while if it exceeds 10% by weight, the antistatic properties will generally be poor. The cross-linked curable resin material of the present invention essentially has at least two acryloyloxy groups and/or methacryloyloxy groups in the above-mentioned molecules. Although the purpose of the present invention can be achieved by including both the compound (A) and the polymerizable acidic phosphate ester (B), it is usually preferable to add a polymerization initiator when implementing the present invention, and in some cases, a polymerization initiator may be added. A compound having a function of promoting the development of antistatic properties by the polymerizable acidic phosphate ester (B) may be further added.

In carrying out the present invention, polymerization and curing of the crosslinked curable resin material is not particularly limited, but photopolymerization using ultraviolet irradiation is preferred because the equipment is relatively simple and productivity is high. Therefore, as the polymerization initiator added to the crosslinked curable resin material, a photosensitizer is preferable. Examples of such photosensitizers include, for example, Pentwin,
Benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, acetoin, benzyl, benzophenone.

carbonyl compounds such as p-methoxybenzophenone,
Tetramethylthiuram monosulfide.

Examples include sulfur compounds such as tetramethylthiuram disulfide. The amount of these photosensitizers added is 0.1 to 100 parts by weight of the above-mentioned crosslinked curable resin material.
Preferably it is 10 parts by weight. If the amount of photosensitizer added is too small, the polymerization and curing of the film will be slow, resulting in low productivity.On the other hand, if the amount added is too large, the weather resistance of the cured film will likely deteriorate.

Examples of compounds that promote the antistatic properties of the polymerizable acidic phosphate ester (B) include (meth)acrylic acid.

Ethylene glycol mono(meth)acrylate.

Diethylene glycol mono(meth)acrylate, triethylene glycol mono(meth)acrylate, tetraethylene glycol mono(meth)acrylate, polyethylene glycol mono(meth)acrylic acid ester with an average molecular weight of about 300 to about 1000, glycerin mono(
Polyhydric alcohol mono(meth) such as acrylate
Examples include acrylates and ethanolamine compounds such as N-laurylgetanolamine and N-stearylgetanolamine, and the amount of these compounds added is at most equivalent to the polymerizable acidic phosphate ester (B). It is preferable that

In addition, in the present invention, after the cross-linked curable resin material has hardened and substantially no longer flows, the synthetic resin molded product with the cross-linked cured film integrally formed on the surface is separated from the mold, and then exposed to air. The film may be further cured in .

The thickness of the cured film provided on the surface of the synthetic resin molded article of the present invention is 1 to 100 μm, preferably 3 to 30 μm.

When the film thickness is less than 1 am, scratch resistance may not be sufficient in some cases, while when the film thickness exceeds 100 μm, the synthetic resin molded product having the film on its surface often becomes brittle.

The synthetic resin molded article used in the present invention is preferably transparent and rigid at room temperature. Specifically, polymethyl methacrylate, a copolymer having methyl methacrylate as a main constituent unit, polystyrene, and a styrene-methyl methacrylate copolymer.

Preferred examples include styrene-acrylonitrile copolymer, polycarbonate, and cellulose acetate butyrate resin.

Further, the shape of these synthetic resin molded products is not particularly limited, but specific examples include plate crystals with a thickness of 0.2 to 20 m, more preferably 0.5 to 10 m.

A method for making a cross-linked curable resin material exist between the mold and the synthetic resin molded product is to apply the cross-linked curable resin material to the molding surface of the mold or onto the synthetic resin molded product, and then combine them with a press roll or the like. A specific example is a method of adjusting the film thickness by pressing and removing air bubbles.

When curing a cross-linked curable resin material, the adhesion between the film and the synthetic resin base material can be dramatically improved by contacting the synthetic resin molded product and/or the cross-linked curable resin material in a heated state. is also accepted. In particular, for polymethyl methacrylate and polymers having methyl methacrylate as the main constituent unit, this heating has a remarkable effect on improving adhesion.

〔Example〕

Hereinafter, the present invention will be explained in more detail with reference to Examples. Parts in the examples represent parts by weight.

The scratch resistance is evaluated by the increase in haze value determined by the falling sand method shown below. That is, the test piece was tilted in advance at an angle of 45° with respect to the horizontal direction, and I I R, P,
M, rotate at a speed of
The increase in haze value is calculated by subtracting the haze value before sand fall from the haze value after sand fall.

Note that the haze value is expressed by the following formula.

The smaller the increase in haze value, the better the scratch resistance.

Moreover, the antistatic property was expressed by the value of charge half-life measured under the following conditions.

That is, under constant temperature and humidity conditions of 20°C and 50% relative humidity.
After holding the sample for 4 hours, a voltage of 10 KV was applied for 10 seconds using an honest meter (manufactured by Shishido Shokai) to measure the half-life.

In addition, changes in the appearance of synthetic resin molded articles after being left unused were determined by observing the appearance after leaving the samples under constant temperature and humidity conditions of 20° C. and 50% relative humidity for 24 hours after manufacture.

Example 1 1.4-butanediol diacrylate 97.5
Department Kayamer PM, 2.
5 parts (monomethacryloxyethyl phosphate, manufactured by Japan (tJ Corporation)) benzoin ethyl ether
A cross-linked curable resin material consisting of 1.5 parts
．． , ×4601+1X61! It was cast on one side of a tempered glass plate of K (thickness), and a colorless and transparent methacrylic resin plate (manufactured by Mitsubishi Rayon Co., Ltd., Acrylite Efoot) heated to 45 ° C. was placed on top of it. The resin material coating was spread from above using a roller so that no air bubbles remained between the resin plate and the glass, so that the thickness of the resin material coating was approximately 10 μm. First, the items in such a state are divided into 100 at regular intervals of 75.
Fluorescent chemical lamp (manufactured by Toshiba, FL-20B)
1 from the methacrylic resin plate side from the height of 6cIrL at L)
Irradiated for minutes. After that, the glass plate was peeled off from the methacrylic resin plate on which the film was formed, and then
2 with this array of high pressure mercury lamps (manufactured by Toshiba, H2O0OL)
The film was post-cured by irradiating the surface on which the film was formed from a height of 0 cIrL for 30 seconds.

The scratch resistance of the film-formed side of the resin plate obtained in this way showed that the haze value increased by 11% using the sand drop method, and the charge half-life was 2 seconds, indicating excellent scratch resistance and antistatic properties. No change in appearance was observed after storage.

Incidentally, the increase in haze value on the surface of the resin plate on which the film was not formed was 55%, and the charge half-life was 120 seconds or more.

Example 2 The cross-linked curable resin material used in Example 1 was 610 mm x 4
60 parts m x 6 mm (thickness) tempered glass plate was cast on one side, and a 1 tnm thick brown smoke colored polycarbonate resin plate (manufactured by Mitsubishi Rayon Co., Ltd.,
Dialite 1530) was placed and spread from above using a roller so that no air bubbles remained between the resin plate and the glass, so that the thickness of the resin material coating was approximately 8 μm. The glass in such a state was first irradiated with 100 fluorescent chemical lamps (manufactured by Toshiba, FL-20BL) arranged at 75-h intervals from a height of 6 crfL for 1 minute from the glass side. After that, the glass plate was peeled off from the polycarbonate resin plate on which the film was formed, and then it was heated for 20 cm using two high-pressure mercury lamps (manufactured by Toshiba, H200OL) arranged at 400 mm intervals.
The film was post-cured by irradiating the surface on which the film was formed for 30 seconds from a height of .

The abrasion resistance of the surface of the resin plate thus obtained on which the film was not formed showed an increase in haze value of 67% using the sand drop method.
The half-life of the charge was over 120 seconds, but the scratch resistance of the surface on which the film was formed increased by 12% in haze value using the sand drop method.
The charge half-life was 2 seconds, the scratch resistance and antistatic properties were excellent, and no change in appearance was observed after standing.

Comparative Example 1 The same film raw material as in Example 1 was heated to 45°C.
The cross-linked curable resin material in Example 1 was applied to one side of a methacrylic resin plate (manufactured by Mitsubishi Rayon Co., Ltd., Acrylai, E#oo1) measuring 1 m x 460 x 3 x 3 (thickness), and the top was stretched under tension. Cover with a 20 μm thick polypropylene film, and spread with a roller from above so that no air bubbles remain between the film and the resin plate, so that the resin material coating has a thickness of approximately 20 μm. did.

Then, it was cured under the same curing conditions as in Example 1 to obtain a resin plate having a cured film on one side.

The abrasion resistance of the surface of the obtained resin plate on which the film was formed showed that the haze value increased by 12% by the sand drop method, and the charge half-life was 45 seconds.

Example 3 The same procedure as in Example 1 was repeated by using a stainless steel plate as the mold and changing the composition of the cross-linked curable resin material as shown below to obtain a resin having a hardened film on its surface. Got the board.

The scratch resistance of the film-formed side of the obtained resin plate showed an increase in haze value of 11%, a charge half-life of 2 seconds, and excellent scratch resistance and antistatic properties. No change in appearance was observed.

Crosslinked curable resin material composition Trimethylolpropane triacrylate 50.
0 parts 1.6-hexanethiol diacrylate)
47.5 parts Kayama P M,
2.5 parts benzoin ethyl ether
1.5 parts [Effect of the invention] As described below, the synthetic resin molded product obtained by the method of the present invention has both scratch resistance and antistatic property, so it has no scratch resistance or antistatic property. It is suitable for use not only in applications where both are required alone, but also in instrument scale plates, see-through panels, CRT front plates, etc. where both are particularly preferred.

Claims (1)

[Claims] 1. Polymerizable compound (A) 90 having at least two acryloyloxy groups and/or methacryloyloxy groups in the molecule between a mold made of inorganic glass or metal and a synthetic resin molded article ~9
9.8% by weight and the following general formula [I] ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ [I] (In the formula, R_1 is hydrogen or a methyl group, R_2 is hydrogen or ▲ Numerical formulas, chemical formulas, tables, etc.) etc. is a ▼ group, R_3 is hydrogen or a methyl group, and m and n are 1 to
A crosslinked curable resin material consisting of 0.2 to 10% by weight of a polymerizable acidic phosphoric acid ester (B) represented by (an integer of 5) is interposed and polymerized and cured, and then a crosslinked cured film is integrally formed on the surface. 1. A method for producing a synthetic resin molded article having a surface with excellent scratch resistance and antistatic properties, the method comprising separating the synthetic resin molded article formed in the mold from the mold. 2. The scratch resistance and antistatic properties as set forth in claim 1, wherein the polymerization and curing of the crosslinked curable resin material is carried out by irradiation with ultraviolet rays in the presence of a photosensitizer. A method for producing a synthetic resin molded product with an excellent surface. 3. The synthetic resin molded product is polymethyl methacrylate, a copolymer whose main constituent unit is methyl methacrylate, polystyrene, styrene-methyl methacrylate copolymer, styrene-acrylonitrile copolymer, polycarbonate, cellulose acetate butyrate 2. The method for producing a synthetic resin molded article having a surface with excellent scratch resistance and antistatic properties as claimed in claim 1, wherein the resin is selected from the group consisting of resins.