JPS60258213A - Manufacture of synthetic resin molded article with highly scratch-resistant surface - Google Patents

Abstract

PURPOSE:To obtain the titled article free from mold release failure by cast polymerization of base material incorporated with specific acid phosphoric ester in a mold lined with cured resin layer such as from (meth)acryloyloxy group- contg. crosslinking-polymerizable compound. CONSTITUTION:The objective article can be obtained by cast polymerization of base resin material (e.g. methyl methacrylate) incorporated with 0.0005-1wt% of acid phosphoric ester of formula (n is 1 or 2; R is 1-18C saturated hydrocarbon) (e.g., monoethyl phosphate) in a mold lined with cured resin formed by curing after coating on the molding surface a liquid film-forming resin material comprising (A) a crosslinking-polymerizable compound with a molecular weight >=150 having at least two (meth)acryloyloxy groups (e.g. trimethylolethane triacrylate) or (B) a mixture of >=30wt% of said compound and a second copolymerizable monomer (e.g. methyl methacrylate) or (C) an oligomer derived from either the component (A) or (B).

Description

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

[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 (
, resistance to abrasion is small □ Due to the small size, the surface of the product is easily scratched during processing or transportation, which not only reduces the product value, but also prevents dust from adhering to the surface of the plastic product during use. When removing dirt such as chips with a cloth, etc., it is easy to cause wiping and scratches, and it is also easy to get abrasion marks from collisions with other objects, and in extreme cases, these scratches can cause damage. It has a fatal drawback in that it loses its optical properties and becomes completely unusable.

For example, the main structural unit is methyl methacrylate. Although the so-called methacrylic resin has excellent transparency and high gloss as one of its most important characteristics, it is also said that its biggest drawback is that its surface is easily scratched.

Various methods have been proposed to improve the scratch resistance of these synthetic resin molded products, but two methods include attaching a resin film with excellent scratch resistance to the surface of the synthetic resin molded product using various methods. This is considered to be the most effective method for improving properties without impairing their properties.

One such method is 2, for example,
No. 147, No. 49-36829.

No. 49-36830, No. 54-14617.

As described in No. 54-14618 and No. 56-53488, there are multiple (
9. A polymerizable composition that becomes a synthetic resin base material after coating and curing a compound having a meta)acryloyloxy group (meaning an acryloyloxy group or a methacryloyloxy group, the same shall apply hereinafter) to form a scratch-resistant film in advance. There is a manufacturing method in which a synthetic resin molded product with excellent scratch resistance is obtained by injecting the resin into a mold and polymerizing it, and transferring a scratch-resistant cured film to the base resin side.

However, although these manufacturing methods are extremely excellent in terms of quality stability and productivity, the curing of the film-forming raw material happens to be defective for some reason, resulting in a non-negligible amount of unpolymerized film-forming raw material. When the base resin raw material is injected and polymerized in the presence of
This may lead to deformation, etc., which reduces the yield of the product and causes an increase in product cost.

[Purpose of the invention]

An object of the present invention is to provide a method for producing a synthetic resin molded article having a surface with excellent scratch resistance, which can solve problem No. 11 of the prior art described above.

[Structure of the invention]

The method for producing a synthetic resin molded article having a surface with excellent scratch resistance according to the present invention is to use a cross-linked polymerizable compound having a molecular weight of 150 or more and at least two acryloyloxy groups and/or methacryloyloxy groups, or a cross-linked polymerizable compound having a molecular weight of 150 or more.
A liquid film-forming resin raw material consisting of a mixture with other copolymerizable monomers containing at least % by weight or a partial polymer thereof is applied to the molding surface of the mold and cured.

In a method of injecting a base resin raw material into a mold to which the obtained resin layer is attached and polymerizing it, the base resin raw material contains a secondary general formula (where n is an integer of 1 or 2, R has a carbon number of 1~
It consists of adding 0.00.05 to 1% by weight of an acidic phosphoric acid ester (representing a saturated hydrocarbon group of 18) and polymerizing it.

Preferred examples of the acidic phosphoric acid ester include monoethyl phonophate, di-ethyl phosphate, heptanobutyl 7-phosphate, di-butyl phosphate, and the like. These compounds may be used alone or in combination of two or more.

The amount of the acidic phosphoric acid ester represented by the general formula [I] in the present invention is 0,0005 to 1% by weight in the base resin raw material. If the amount added is less than 0.0005% by weight, the effect of preventing poor peeling, which is the objective of the present invention, will be insufficient, while if it exceeds 1% by weight, the heat distortion temperature 9 of the resin molded product will decrease in mechanical strength. It tends to be recognized.

Specific examples of the crosslinking polymerizable compound having a molecular weight of 150 or more and at least two (meth)acryloyloxy groups used to constitute the film-forming raw material of the present invention include polyhydric alcohol and acrylic acid. Preferable examples include diethylene glycol-nt: 3/JJN Maca II l/L/,
-Fka II +/ -kJ or methacrylate),
Triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, 1.4
-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate.

Examples include trimethylolethane triacrylate, trimethylolpropane triacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, and pentaglycerol triacrylate.

In addition, as the film-forming raw material of the present invention, esters of polyhydric alcohol, polycarboxylic acid, and acrylic acid can be used. (meth)acrylic acid or these 1,4
Preferred examples include esterified products obtained by adding and reacting -butanediol or 1,6-hexanediol.

These crosslinking polymerizable compounds can be used alone or as a mixture thereof. Moreover, it can also be used as a mixture with other polymerizable monomers containing 30% by weight or more of these crosslinking polymerizable compounds. If the amount of the cross-linked polymerizable compound in the film-forming raw material is less than 30% by weight, the film obtained by polymerizing and curing it will swell with the base resin raw material, tend to cause linear cracks, and deteriorate the scratch resistance. The improvement is also not significant compared to the case of using only the base resin.

Other copolymerizable monomers that can be used in combination with the crosslinked polymerizable compound of the present invention include acrylic acid, methacrylic acid, esters thereof, acrylonitrile, and methacrylate trile.

Examples include styrene and its derivatives.

As the polymerization initiator mixed with the film-forming resin raw material, a known thermally decomposable radical polymerization initiator 2, such as an oil-soluble peroxide or an azo compound, is suitable, and it has a photosensitizing effect. 4, □, 6 □ 3000-4000.

, □ )・□ Radical generators that can be activated are effective, and are generally carbonyl compounds, azo compounds,
Peroxides, sulfur compounds, and norogen compounds.

Quinone compounds etc. can be used, and these are not one type but two types.
It is also possible to use a combination of more than one species. Further, sources of ultraviolet rays include mercury lamps, arc lamps, xenon lamps, and the like.

In addition, when curing these film-forming resin raw materials,
Antistatic agents and additives as required.

Auxiliary agents etc. can also be added.

The amount of the polymerization initiator added is preferably 0.1 to 5 parts by weight based on the monomer. When the amount added does not reach 0.1 part by weight, the curing of the film-forming resin raw material is slow;
When the amount exceeds 1 part by weight, the weather resistance of the scratch-resistant cured film tends to decrease.

Further, the viscosity of the film-forming resin raw material is preferably in the range of 1 to 1,000 centivoise, and more preferably 5 to 1,000 centivoise.
More preferably, it is 1000 centipoise.

The base resin raw materials used in the present invention include:

Methyl methacrylate or methyl methacrylate 80
It is a mixture of polymerizable unsaturated monomers containing at least % by weight or a partial polymer thereof.

Examples of polymerizable unsaturated monomers that can be copolymerized with methyl methacrylate include acrylic esters such as methyl acrylate, ethyl acrylate, and 2-ethylhexyl acrylate, and methacrylic esters such as ethyl methacrylate.

Examples include styrene and its derivatives.

Examples of the polymerization initiator for the base resin raw material include azobisisobutyronitrile, azobisdimethylvaleronitrile, benzoyl peroxide, lauroyl peroxide, 2,4-dichlorobenzoyl peroxide, and isopropyl peroxydicarbonate. , inbutyl peroxide.

Free radical initiators such as acetylcyclohexylsulfonyl peroxide can be used. It is also possible to use a redox polymerization initiator 1, for example, a combination of peroxides and amines. Furthermore, the base resin raw material may contain various additives 2, such as stabilizers, as needed.
Flame retardants, plasticizer bipolymerization regulators, dyes/pigments, etc. may be added.

The method for producing a synthetic resin molded product having a surface with excellent scratch resistance according to the present invention using the above-mentioned sticky film-forming resin raw material and base resin raw material is described in Japanese Patent Publication No. 47-1314 described above.
No. 7, No. 49-36829, No. 49-36830,
It can be applied to the methods described in Japanese Patent Publication No. 54-14617, No. 54-14618, and No. 56-53488, etc., and among these, from the viewpoint of productivity,
Particularly preferred is application to the method using the continuous plate making apparatus described in No. 88.

〔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. In other words, the test piece was placed in advance at a 45° angle to the horizontal direction.
around the vertical axis K 11 R,P
Let it rotate at a speed of ,M.

60 meshes of Carborundum 300F were dropped from 70 cm above the test piece at a speed of 15017 minutes, and the increase in haze value was 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.

Example 1 100 parts of trimethylolethane triacrylate,
A film raw material mixed with 1 part of benzoin ethyl ether,
It was cast onto one side of a tempered glass plate with a size of approximately 1420 + ut x 1170 Ioms (thickness), and then covered with a 0.02 mx thick polypropylene film cover with tension on all four sides.

The coating material was spread over the film using a roller, so that the thickness of the coating film was 0.02 mm so that no air bubbles remained between the film and the glass plate. However, 2
The cover film was locally lifted from the coating material, and air was left behind between the coating material and the cover film.

In such a state, use a chemical lamp [manufactured by Kishita Denki, FLR120EH, BA-37/AC (tube length 1500
After pre-curing by irradiating for 30 seconds at an irradiation distance of 150 mm, the cover film was peeled off and a high-pressure mercury lamp was used in the absence of the cover film. Made by Toshiba (H4000L/3.
Three tubes with a tube length of 1480+g and a power of 4KW) were arranged at intervals of 400 meters and were irradiated for 30 seconds at an irradiation distance of 2001 m for post-curing. Although the raw material for the film was not substantially cured in the areas where the cover film was exposed due to the ultraviolet irradiation, the other parts were sufficiently cured.

The thus treated glass plate was placed opposite the untreated glass so that the cured film was on the inside, and between them, 10.05 parts of azobisisobutyronitrile/I and a mixture of monoethyl phosphate and di-ethyl 7-osphate (Nippon Kagaku Inject methyl methacrylate partial polymer containing 0.01 part of Kogyo Co., Ltd. (trade name: rEAP J), seal the 2 peripheries with a soft vinyl chloride gasket, and adjust the spacing between the molded glasses so that there are 3 resin plates. and heated at 60°C for 6 hours, then 1
Polymerization was carried out by heating at 20° C. for 2 hours.

When the resin plate is then cooled, it is easily peeled off from the glass plate, and although scratch resistance is not observed in the raised areas of the cover film, the haze value increases by 1 in other areas.
The scratch resistance was excellent at 3%.

Comparative Example 1 The same operation as in Example 1 was repeated except that [EAPJ was removed from the resin raw material to be injected. At this time, the cover film lifts up after cooling, and the peeling of the resin plate from the glass plate becomes extremely poor in areas where the film raw material is not substantially cured, and the corresponding glass plate surface adheres to the resin plate surface. It was ripped off and the glass pane was damaged.

Example 2 1 mol of trimethylolethane, 0.5 mol of conolic acid,
By carrying out an esterification reaction using 2.2 moles of acrylic acid as a raw material, the viscosity at 20°C is 57oO centiboise, the bromine number is 100°, and the oxidation rate is 8.2 my KOH/
g of product was obtained. 1,6- for 40 parts of this product
60 parts of hexafushiol diacrylate and 1.5 parts of pentwinethyl ether were added and used as a coating material.

It was described in FIG. 2 detailed in Example 7 of Japanese Patent Publication No. 56-53488. They move in the same direction and at the same speed. The above film raw material was cured using a device using a pair of stainless steel endless belts to continuously produce a methacrylic resin plate having a surface with excellent scratch resistance.

At this time, at the start and end of operation of the apparatus, a substantially uncured portion of the film raw material was generated on the belt in a length of about 20 parts in the direction of belt movement, but 80 parts of methyl methacrylate monomer, 20 parts of polymethacrylic acid with an average degree of polymerization of 900, 0.02 part of 2,2'-azobis(2,4-dimethylvaleronitrile) as a polymerization initiator, and a mixture of motuputyl phosphate and di-butyl phosphate (reduced). Manufactured by Kagaku Kogyo Co., Ltd. Product name: JP 504
J) When 0.05 part of the resin was injected and polymerized, scratch resistance was not observed in the substantially uncured portion of the film raw material, but the peeling of the 2M1L thick resin plate from the endless belt was good. The hardened portion of the film raw material had an increase in haze value of 11% and had excellent scratch resistance.

Comparative Example 2 The same operation as in Example 2 was repeated except that "JP 504" was removed from the resin raw materials to be injected.

At this time, the peeling of the resin plate from the endless belt was extremely poor due to the substantially uncured portions of the coating raw material that occurred at the start and end of operation of the equipment, and the resin plate cracked during peeling.1. ,.

Ta.

〔Effect of the invention〕

The manufacturing method of the present invention involves polymerizing a base resin raw material in a mold with a crosslinked cured film provided on the inner surface of the mold.

When manufacturing synthetic resin molded products with surfaces with excellent scratch resistance, poor peeling between the mold and the polymerized synthetic resin molded product can be avoided, resulting in cracks in the synthetic resin, damage and deformation of the mold, etc. This has the great advantage of being able to eliminate defects, improve product yield, and significantly reduce product costs.

Claims (1)

[Scope of Claims] 1. A cross-linked polymerizable compound having a molecular weight of 150 or more and having at least two acryloyloxy groups and/or methacryloyloxy groups, or 30% by weight of this compound.
A liquid film-forming resin raw material consisting of a mixture with other copolymerizable monomers containing the above or a partial polymer thereof is applied to the mold molding surface and cured, and the resulting mold is attached with a resin layer. In the method of polymerizing by injecting a base resin raw material into the base resin raw material, 0.0005% of an acidic phosphoric ester represented by the following general formula (representing a saturated hydrocarbon group having 1 to 18 carbon atoms) is added to the base resin raw material. A method for producing a synthetic resin molded article having a surface with excellent scratch resistance, characterized by adding ~1% by weight and polymerizing.