JPH09241312A - Photocurable composition for artificial marble and method for curing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide artificial marble products having good transparent appearance and surface smoothness by photocuring a composition for artificial marble by using a specified photopolymerization initiator having an absorption in the region of visible light instead of a thermal polymerization initiator conventionally used in such a composition. SOLUTION: This composition contains a polymerizable unsaturated compound, inorganic and/or organic fillers and a photopolymerization initiator being a bisacylphosphine oxide represented by the formula [wherein R<1> to R<3> , which are independent of each other, are (substituted) alkyls, (substituted) aryls, (substituted) allyl groups, (substituted) aralkyls, (substituted) alkenyls, (substituted) alkynyls or (substituted) heterocyclic groups]. The mixing ratio is usually such that about 1-1000 pts. wt. inorganic and/or organic fillers and about 0.01-2.0 pts.wt. compound represented by the formula are present per 100 pts.wt. polymerizable unsaturated compound. This composition is poured into a form and cured by irradiation with light at wavelength of 400-500nm.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a composition for artificial marble that can be cured by irradiation with light and a method for curing the composition. More specifically, the present invention relates to a composition for artificial marble which can be photocured in a short time and at a low temperature even when it contains a pigment and the like and has a thickness of about 1.5 cm, and a curing method by irradiation with light.

[0002]

2. Description of the Related Art Generally, artificial marble is a mixture of a curable resin and an inorganic and / or organic filler, which is then cured and molded into a plate shape, which gives a transparent feeling like natural marble. It has a white color, a milky white color, a slight color, or a color with a marble pattern. In recent years, the demand is increasing, for example, it is used for household appliances such as wash basins and bath tubs, and ornaments. For more information on artificial marble, see "Reinforced Plastics (June 1995, 181-184)".
It is described in.

Conventionally, there are artificial marbles based on curable (meth) acrylic resins and those based on unsaturated polyester resins or vinyl ester resins. Among them, artificial marble based on unsaturated polyester resin or vinyl ester resin has been remarkably growing in demand in recent years because of its characteristics such as easy adaptability to complicated shapes, excellent heat resistance and excellent appearance.

As a method for producing an artificial marble based on an unsaturated polyester resin or a vinyl ester resin, there are a casting method and a heat and pressure molding method.

The casting method is a method in which an unsaturated polyester resin or vinyl ester resin, a filler, a glass powder, and a thermal polymerization initiator are mixed and then poured into a mold, followed by heat curing and molding. JP-A-7-33498). Artificial marble produced by the casting method is characterized by its excellent transparency and surface smoothness. However, since a thermal polymerization initiator such as a peroxide is used as the polymerization initiator, the curing time is as long as about 1.0 to 1.5 hours, and the productivity is extremely low.

On the other hand, the heat and pressure molding method is a method in which a raw material composition similar to the casting method is molded under high temperature and high pressure using a pressing machine. The curing time is 7 to 15 minutes, which is shorter than that of the casting method and the productivity is high.
-3130).

However, due to curing shrinkage when the composition is cured or heat shrinkage due to cooling, adhesion failure at the interface between the resin and the filler occurs, and the transparency of the obtained product is low. To do. In addition, surface smoothness may be impaired, and cracks may be generated. In order to solve these problems, recently, attempts have been made to add a thermoplastic resin as a low-contracting agent to maintain surface smoothness and prevent cracks. However, when a thermoplastic resin is added, the transparency of the product is further deteriorated, and as artificial marble, there is a drawback that only a transparency far from the transparency obtained by the casting method can be obtained. Further, as a drawback of the heat and pressure molding method, a large amount of equipment cost is required.

On the other hand, as an example of using a bisacylphosphine oxide compound as a photopolymerization initiator, Japanese Patent Laid-Open No.
1-1230296, JP-A-2-1401, and the like. However, all of them are merely applied to compositions for dental materials, and there is no example of application to compositions for artificial marble.

[0009]

SUMMARY OF THE INVENTION The present invention solves the above problems in producing artificial marble. That is, according to the present invention, a product having transparency equal to or more than artificial marble obtained by the casting method, and surface smoothness,
It is possible to provide a novel composition for artificial marble, which can be obtained with a productivity higher than that of the heat and pressure molding method, and a curing method thereof.

[0010]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies to solve the above-mentioned problems in producing artificial marble, and as a result, a thermal polymerization initiator conventionally used in compositions for artificial marble. Instead of the above, it was found that the problem can be solved by using a photopolymerization initiator having a specific structure having absorption in the visible light region and by photocuring, and completed the present invention.

That is, a photocurable artificial marble containing a polymerizable unsaturated compound, an inorganic and / or organic filler, and a bisacylphosphine oxide compound of the following general formula (1) which is a photopolymerization initiator. Composition,

General formula (1);

Embedded image (In the formula, R ^{1 to} R ³ are each independently an alkyl group, an aryl group, an allyl group, an aralkyl group, an alkenyl group, an alkynyl group, a heterocyclic group, a substituted alkyl group, a substituted aryl group, a substituted allyl group, a substituted aralkyl group. Group, substituted alkenyl group, substituted alkynyl group or substituted heterocyclic group)

And a general formula (1) which is a polymerizable unsaturated compound, an inorganic and / or organic filler, and a photopolymerization initiator.
The composition for artificial marble, which contains the bisacylphosphine oxide compound described in 1. above, is poured into a mold and is irradiated with light having a wavelength of 400 to 500 nm to be cured, and the composition for artificial marble. The above object was achieved by developing a curing method for

A feature of the present invention is that a bisacylphosphine oxide compound represented by the general formula (1) is used as a photopolymerization initiator for a composition for artificial marble. This initiator is more sensitive to light in the longer wavelength region (visible light region of 400 nm or more) than conventional UV initiators and is excellent in light transmission, and is cleaved by light irradiation to generate an acyl radical and a phosphinoyl radical. Because
It is said that the polymerization initiation efficiency is higher than that of the conventional UV initiator.

Specific examples of the bisacylphosphine oxide compound of the general formula (1) used in the present invention include bis (2,6-dichlorobenzoyl) -phenylphosphine oxide and bis (2,6-dichlorobenzoyl). −
2,5-Dimethylphenylphosphine oxide, bis (2,6-dichlorobenzoyl) -4-ethoxyphenylphosphine oxide, bis (2,6-dichlorobenzoyl) -4-biphenylylphosphine oxide, bis (2,6 -Dichlorobenzoyl) -4-propylphenylphosphine oxide, bis (2,6-dichlorobenzoyl) -2-naphthylphosphine oxide, bis (2,6-dichlorobenzoyl) -1-naphthylphosphine oxide, bis (2 , 6-dichlorobenzoyl)
-4-chlorophenylphosphine oxide, bis (2,6-dichlorobenzoyl) -2,4-dimethoxyphenylphosphine oxide, bis (2,6-dichlorobenzoyl) -decylphosphine oxide, bis (2,6-di) Chlorobenzoyl) -4-octylphenylphosphine oxide, bis (2,6-dichlorobenzoyl) -2,5-dimethylphenylphosphine oxide, bis (2,6-dichlorobenzoyl) -phenylphosphine oxide, bis (2,2 4,6-Trimethylbenzoyl) -2,5-dimethylphenylphosphine oxide, bis (2,6-dichloro-3,4,5-trimethoxybenzoyl) -2,5-dimethylphenylphosphine oxide, bis (2,6) -Dichloro-3,4,
5-trimethoxybenzoyl) -4-ethoxyphenylphosphine oxide, bis (2-methyl-1-naphthoyl) -2,5-dimethylphenylphosphine oxide, bis (2-methyl-1-naphthoyl) -2,5-phenyl Phosphine oxide, bis (2-methyl-1-)
Naphthoyl) -4-biphenylylphosphine oxide, bis (2-methyl-1-naphthoyl) -4-ethoxyphenylphosphine oxide, bis (2-methyl-)
1-naphthoyl) -2-naphthylphosphine oxide, bis (2-methyl-1-naphthoyl) -4-propylphenylphosphine oxide, bis (2-methoxy-1-naphthoyl) -2,5-dimethylphenylphosphine oxide, bis (2-Methoxy-1-naphthoyl) -4-ethoxyphenylphosphine oxide, bis (2-methoxy-1-naphthoyl) -4-biphenylylphosphine oxide, bis (2-chloro-1-naphthoyl) -2,5- Dimethylphenylphosphine oxide, bis (2,6-dimethoxybenzoyl) -2,
4,6-trimethylpentylphosphine oxide and the like can be mentioned.

These initiators are added in a proportion of 0.01 to 2.0 parts by weight based on 100 parts by weight of the total amount of the polymerizable unsaturated compound. It is preferably 0.01 to 0.5 parts by weight. More preferably, it is 0.04 to 0.2 parts by weight.
The amount of these initiators added is such that the total amount of polymerizable unsaturated compounds is 1
If the amount is less than 0.01 parts by weight with respect to 00 parts by weight, curing may not proceed sufficiently and the strength of the cured product may be insufficient. If the amount is more than 2.0 parts by weight, unreacted initiator may remain in the cured product after photocuring, and the cured product may be colored. The initiator may be used alone or in combination of two or more.

Examples of the polymerizable unsaturated compound used in the present invention include unsaturated polyester resins, vinyl ester resins, curable (meth) acrylic resins and the like. Hereinafter, each resin will be described.

The unsaturated polyester resin may be a product obtained by reacting an acid or its anhydride with an alcohol by a known method.

Specific examples of the acid or its anhydride include phthalic anhydride, isophthalic acid, terephthalic acid, tetrahydrophthalic acid, adipic acid and the like, saturated polybasic acids having no active unsaturated bond, or their anhydrides, and fumaric acid. Unsaturated polybasic acid having an active unsaturated bond such as acid, maleic anhydride, maleic acid, and itaconic acid, or an anhydride thereof, and if necessary, benzoic acid, abietic acid, dicyclopentenyl maleic acid half ester And monocarboxylic acids such as Specific examples of alcohols include ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, 1,2-butanediol, 1,3-butanediol, 1,5-pentanediol, 1,6-hexanediol, and 2; -Methyl-
1,3-propanediol, 2,2-dimethyl-1,3
Examples thereof include polyhydric alcohols such as propanediol, cyclohexane-1,4-dimethanol, an ethylene oxide adduct of bisphenol A, and a propylene oxide adduct of bisphenol A.

The vinyl ester resin is produced by a known method, and is an epoxy (meth) resin obtained by reacting an epoxy resin with (meth) acrylic acid.
Polyester obtained by reacting an epoxy compound having an α, β-unsaturated carboxylic acid ester group with a polyester having a terminal carboxyl group obtained from acrylate or saturated dicarboxylic acid and / or unsaturated dicarboxylic acid and polyhydric alcohol (meth ) Examples include acrylate.

Examples of the epoxy resin as a raw material for the vinyl ester resin include bisphenol-A-diglycidyl ether and its high molecular weight homologues, novolac type polyglycidyl ethers and the like.

As the saturated dicarboxylic acid, a dicarboxylic acid having no active unsaturated group, for example, phthalic acid,
Isophthalic acid, terephthalic acid, tetrahydrophthalic acid,
Examples thereof include adipic acid and sebacic acid. Examples of unsaturated dicarboxylic acids include dicarboxylic acids having an active unsaturated group, such as fumaric acid, maleic acid, fumaric anhydride, and itaconic acid.

Further, as the polyhydric alcohol component, for example, ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, 1,2-
Butanediol, 1,3-butanediol, 1,5-pentanediol, 1,6-hexanediol, 2-methyl-1,3-propanediol, 2,2-dimethyl-
1,3-propanediol, cyclohexane-1,4-
Examples thereof include polyhydric alcohols such as dimethanol, an ethylene oxide adduct of bisphenol A, and a propylene oxide adduct of bisphenol A.

A typical example of the epoxy compound containing an α, β-unsaturated carboxylic acid ester group is glycidyl methacrylate.

The curable acrylic resin includes, for example, curable (meth) acrylate, and specifically, 1,4-butanediol dimethacrylate and 1,6
-Urethane formed by the reaction of (meth) acrylate or hydroxyalkyl (meth) acrylate with a compound having at least two isocyanate groups such as hexanediol dimethacrylate, trimethylolpropane triacrylate, pentaerythritol trimethacrylate, and pentaerythritol tetraacrylate. Acrylate etc. are mentioned.

The filler used in the present invention may be an inorganic type or an organic type. Specifically, inorganic resins such as magnesium hydroxide, calcium carbonate, glass, silica, alumina white, and aluminum hydroxide, or organic resins and inorganic materials represented by powders produced by crushing artificial marble. Mixed fillers and the like.

However, in order not to impair the transparency of the obtained artificial marble, it has a refractive index close to that of the curable acrylic resin, vinyl ester resin or unsaturated polyester resin used in the composition for artificial marble. It is preferable to choose a filler. Specifically, it is preferable to use silica in the case of a curable acrylic resin, glass in the case of an unsaturated polyester resin or vinyl ester resin, and aluminum hydroxide.

Examples of the shape of the filler include powdery, spherical, fibrous, whisker-like, and scale-like inorganic materials, organic materials, their composites, and mixtures.

The amount of the filler added is generally 1 to 1000 parts by weight based on 100 parts by weight of the total amount of the polymerizable unsaturated compound. It is preferably 10 to 500 parts by weight, more preferably 20 to 300 parts by weight. If the amount of the filler added is less than 1 part by weight, the physical properties required for the cured product such as hardness are insufficient, and internal stress increases due to curing shrinkage during polymerization, which is not preferable. In addition, the addition amount of the filler is 1000
If the amount is more than the weight part, the light transmittance is lowered and the curing reaction does not proceed sufficiently, or the flowability when the composition for artificial marble is poured into the mold is extremely deteriorated, and the workability may be lowered. is there.

In the composition of the present invention, the kneading property and the impregnating property of the polymerizable unsaturated compound and the filler are enhanced, and the hardness, strength, chemical resistance and water resistance of the molded product are adjusted. Reactive diluents such as styrene monomers and methylmethacrylate can be added for purposes. Although the amount of the reactive diluent used is not particularly limited, it is generally 0 to 250 parts by weight, preferably 20 to 100 parts by weight with respect to 100 parts of the unsaturated polyester resin, vinyl ester resin or curable acrylic resin. When the amount used exceeds 250 parts, the chemical resistance of the cured product to solvents and the like becomes extremely poor.

Specific examples of the compound used as the reactive diluent include aromatic monomers such as styrene, α-methylstyrene, p-methylstyrene and chlorostyrene, methyl methacrylate, isobutyl (meth) acrylate and isobornyl (meth). ) Acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, 2-hydroxy-3-
(Meth) acrylate monomers such as phenoxypropyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, polyoxyethylene (meth) acrylate,
Examples thereof include N-substituted acrylamides such as N, N-dimethylacrylamide, N, N-diethylacrylamide and N-acryloylmorpholine.

However, considering the refractive index for the same reason as that of the filler, (meth) acrylate in the case of a curable (meth) acrylic resin and styrene in the case of an unsaturated polyester resin or a vinyl ester resin are particularly preferable.

Further, various polymerization accelerators and the like can be added to the composition of the present invention for the purpose of promoting the curing reaction efficiently. Examples of the polymerization accelerator include a thermal polymerization initiator, a redox polymerization initiator and a cationic polymerization initiator.

Specifically, as the thermal polymerization initiator, t-butyl peroxy neodecanoate, t-butyl peroxypivalate, lauroyl peroxide, t-hexyl peroxypivalate, t-butyl peroxyiso are used. Various peroxides such as butyrate, new oily azobis compounds such as azobisisobutyronitrile, and redox initiators include t-butylperoxy neodecanoate, t-butylperoxypivalate, lauroyl peroxide,
Combinations of various oxidizers such as t-hexyl peroxypivalate and t-butyl peroxyisobutyrate with aromatic thiol compounds such as mercaptobenzimidazole and trimercaptotriazine, t-butylperoxyneodecanoate and t-butyl. Combination of various oxidizing agents such as peroxypivalate, lauroyl peroxide, t-hexyl peroxypivalate, t-butyl peroxyisobutyrate and diketones such as dimedone, and iodonium salts and sulfonium salts as cationic polymerization initiators. And the like, and the compounds can be added to the extent that the hue of the cured product produced from these compounds is not impaired.

In the composition of the present invention, various pigments, leveling agents generally used as additives for paints,
If necessary, a plasticizer, a defoaming agent, a thickener, a polymerization inhibitor, an antioxidant and the like can be added to the extent that the hue, chemical resistance and hot water resistance of the resulting cured product are not impaired.

Curing of the composition of the present invention is generally performed by the following procedure. First, a composition for artificial marble obtained by sufficiently kneading various components is highly transparent and easily transmits light such as a glass fiber reinforced plastic mold, a silicone resin mold, and a glass mold so that air bubbles do not enter. Pour into the formwork,
Next, light containing a wavelength region of 400 to 500 nm is irradiated to cure the composition.

Although the thickness of the artificial marble is arbitrarily determined as necessary, it is generally in the range of 5 mm to 2 cm. If it is thicker than necessary, it will take longer than necessary to cure,
In some cases, the cured product may be insufficiently cured, which is not preferable.

The light source may be any one as long as it has a spectral distribution in the photosensitive wavelength region of the initiator in the composition and is capable of irradiating light with an intensity capable of causing a photoreaction, for example, a halogen lamp, a xenon lamp, a mercury lamp. , Metal halide lamps, sunlight, etc. are used. Two or more kinds of light sources may be used in combination so as to match the photosensitive wavelength of the photoinitiator. The light intensity required for the method for producing an artificial marble of the present invention is the photosensitivity (photosensitivity) of the initiator, the curability of the polymerizable compound, the type of filler,
The amount is generally 10 mJ / cm ² or more, preferably 100 although it depends on the amount and the thickness of the artificial marble to be produced.
The light intensity is mJ / cm ² or more. If the light intensity is too low, the photoreaction does not proceed sufficiently, and the curing reaction of the artificial marble cured product may be insufficient, or the curing in the depth direction may become uneven.

Regarding the wavelength of light, there is a problem in safety with only light having a wavelength shorter than 400 nm, and curing in the depth direction may become uneven. On the contrary, if there is no photosensitivity of the initiator with only light having a wavelength longer than 500 nm,
Since the photosensitivity is extremely low, curing does not proceed, so 400
It is necessary to irradiate light containing a wavelength of ˜500 nm.

In order to accelerate the polymerization reaction, the artificial marble composition may be heated and poured into a mold. In general, it is preferable to irradiate light having a wavelength in the infrared region such as a halogen lamp and sunlight because the temperature of the irradiated object rises due to the action of heat rays to accelerate the curing reaction.

[0041]

The present invention will be described below with reference to examples. However, the present invention is not limited to the following examples. In the following description, "part" means "part by weight" unless otherwise specified.

(Examples 1 to 4) Vinyl ester resin
[Brand name: Lipoxy RF-312-7 Showa High Polymer Co., Ltd.] 100 parts, inorganic hydroxide aluminum hydroxide [Brand name: Heidilite NB-1 Showa Denko KK] 200 parts, table The photopolymerization initiator described in 1 was added, and the mixture was deaerated with a vacuum pump for 10 minutes while stirring. A 9 mm thick spacer is sandwiched between glass plates, a resin solution is poured into the glass plate, the lid is covered, and a 1.5 kW halogen lamp is used to irradiate and cure for 10 minutes at an irradiation distance of 30 cm until the temperature of the cured product reaches room temperature. After cooling with water, peeling from the glass plate, and leaving for 1 day, visually observing the presence or absence of coloring of this artificial marble cured product and the smoothness of the back surface, and further observing the front surface (light irradiation surface) and the back surface (light irradiation surface rear surface). The hardness of the surface) was measured with a Barcol hardness meter (hard). In addition, in order to compare the transparency of this artificial marble cured product, the total light transmittance of a molded product with a thickness of 9 mm was measured by Tokyo Denshoku Co., Ltd. Fully Automatic Haze M.
It was measured using ETER TC-H3DP type. Furthermore, for the boiling test, the back surface of the artificial marble cured product was
The color difference (ΔE) after 100 hours, 200 hours, and 300 hours was adjusted so as to be in contact with hot water at 6 ° C., and Spectro Colori Meter SQ- manufactured by Nippon Denshoku Industries Co., Ltd.
Was measured using 300H. However, the color difference (ΔE) at each time was evaluated based on the value before contact with hot water. The results are shown in Tables 2 and 3.

[0043]

[Table 1]

[0044]

[Table 2]

[0045]

[Table 3]

Comparative Example 1 Vinyl Ester Resin [Brand Name: Lipoxy RF-312-7 Showa Highpolymer Co., Ltd.]
Aluminum hydroxide as an inorganic filler in 100 parts
[Product name: Heidilite NB-1 Showa Denko KK
200 parts, 1.5 parts of [trade name: Percure HO Nippon Oil & Fats Co., Ltd.] and 1.0 parts of [trade name: Perloyl TCP Nippon Oil & Fats Co., Ltd.] as a polymerization initiator, and stirred. While degassing with a vacuum pump for 10 minutes. A 9 mm-thick spacer is sandwiched between glass plates, a resin solution is poured into the glass plate, the lid is placed, the product is placed in a drier at 80 ° C., left for 10 minutes, then taken out from the drier, and cooled with water until the temperature of the cured product reaches room temperature, After peeling from the glass plate and leaving for 1 day, visually observe the presence or absence of coloring of the artificial marble cured product and the smoothness of the back surface, and further measure the hardness of the surface and the back surface of this artificial marble cured product with a Barcol hardness tester (hard). I tried to measure. However, the hardness of the cured product is a Barcol hardness tester (hard) on both sides.
The hardness was not measurable by.

(Comparative Example 2) Vinyl ester resin [trade name: Lipoxy RF-312-7 manufactured by Showa Highpolymer Co., Ltd.]
Aluminum hydroxide as an inorganic filler in 100 parts
[Product name: Heidilite NB-1 Showa Denko KK
200 parts, and 2 parts of a 50% solution of t-amylperoxy-2-ethylhexanoate [trade name: Trigonox 121-50 manufactured by Kayaku Akzo Co., Ltd.] as a polymerization initiator are added, and 10 parts are added while stirring. Degas with a vacuum pump for a minute.
These mixtures are put into a mold with a thickness of 14 mm, press-molded under the conditions of temperature 115 ° C., pressure 100 tons and pressure time 10 minutes to produce a 9 mm thick flat plate-shaped artificial marble. Obtained. After standing for 1 day, the hardness of the front and back surfaces of this artificial marble cured product was measured with a Barcol hardness tester (hard). Also, this molded product was visually observed for the presence or absence of coloration and the smoothness of the back surface, and the total light transmittance of the molded product with a thickness of 9 mm was measured by Tokyo Denshoku Co., Ltd. Fully Automatic Haze Meter.
It was measured using TC-H3DP type. Further, regarding the boiling test, the back surface of the artificial marble cured product was brought into contact with hot water at 96 ° C., and the color difference (ΔE) after 100 hours, 200 hours and 300 hours was measured by Nippon Denshoku Industries Co., Ltd. SPECT.
It measured using RO COLORI METER SQ-300H. However, the color difference (ΔE) at each time was evaluated based on the value before contact with hot water. The results are shown in Table 2,
The results are shown in Table 3.

(Examples 5 to 8) Unsaturated polyester resin [Product name: Yupika 6424 manufactured by Japan Yupica Co., Ltd.] 1
Aluminum hydroxide [trade name: Heidilite NB-1 Showa Denko KK] 20 which is an inorganic filler in 00 parts
0 part of the photopolymerization initiator shown in Table 1 was added, and the mixture was deaerated with a vacuum pump for 10 minutes while stirring. 9mm thick on glass plate
Sandwich the spacer of, pour in the resin liquid and close the lid.
Using a kW halogen lamp, 10 at irradiation distance of 30 cm
It is irradiated and cured for a minute, cooled with water until the temperature of this cured product reaches room temperature, then peeled off from the glass plate and left for 1 day, and then visually observed for the presence or absence of coloring of this artificial marble cured product and the smoothness of the back surface, Further, the hardness of the front surface (light-irradiated surface) and the back surface (surface on the back side of the light-irradiated surface) were measured with a Barcol hardness meter (hard). In addition, in order to compare the transparency of this artificial marble cured product, the total light transmittance of a molded product with a thickness of 9 mm was measured by Tokyo Denshoku Co., Ltd. Fully Automatic Haze METER TC-H.
It was measured using a 3DP type. Further, regarding the boiling test, the back surface of the artificial marble cured product was brought into contact with hot water at 96 ° C., and the color difference (ΔE) after 100 hours, 200 hours, and 300 hours was measured by Nippon Denshoku Industries Co., Ltd.
Was measured using a COLORI METER SQ-300H. However, the color difference (ΔE) at each time was evaluated based on the value before contact with hot water. Tables 2 and 3 show the results.
It was shown to.

Comparative Example 3 Unsaturated polyester resin
[Brand name: Yupica 6424 Nippon Yupica Co., Ltd.] 10
In 0 parts, aluminum hydroxide, an inorganic filler [trade name: Heidilite NB-1 Showa Denko KK] 200
Part, as a polymerization initiator [trade name: Percure HO Nippon Oil & Fats Co., Ltd.] 1.5 parts, [trade name: Perloyl TCP
1.0 part of Nippon Oil & Fats Co., Ltd. was added and deaerated with a vacuum pump for 10 minutes while stirring. 9mm thick on glass plate
Sandwich the spacer, pour in the resin liquid and cover with a lid,
In the dryer, leave it for 20 minutes, then remove from the dryer, cool it with water until the temperature of the cured product reaches room temperature, peel it from the glass plate, and leave it for 1 day, and then check whether the artificial marble cured product is colored or not. Was visually observed, and the hardness of the front and back surfaces of this artificial marble cured product was measured with a Barcol hardness meter (hard). However, the hardness of the cured product was not so high as to be measured by a Barcol hardness tester (hard) on both sides.

(Comparative Example 4) Unsaturated polyester resin
[Brand name: Yupica 6424 Nippon Yupica Co., Ltd.] 10
In 0 parts, aluminum hydroxide, an inorganic filler [trade name: Heidilite NB-1 Showa Denko KK] 200
Parts, 2 parts of a 50% solution of t-amylperoxy-2-ethylhexanoate [trade name: Trigonox 121-50 manufactured by Kayaku Akzo Co., Ltd.] as a polymerization initiator, and a vacuum pump for 10 minutes while stirring. Degassed. These mixtures are put into a mold having a thickness of 14 mm and the temperature is set to 115.
Press molding was carried out under conditions of a temperature of 100 ° C., a pressure of 100 tons and a pressing time of 10 minutes to obtain a flat plate-shaped artificial marble having a thickness of 9 mm. After standing for 1 day, the hardness of the front and back surfaces of this artificial marble cured product was measured with a Barcol hardness tester (hard). In addition, this molded product was visually observed for comparison of the presence or absence of coloring and the smoothness of the back surface, and the total light transmittance of the molded product having a thickness of 9 mm was measured by Tokyo Denshoku Co., Ltd. Fully Automatic Haze METER TC-H.
It was measured using a 3DP type. Further, regarding the boiling test, the back surface of the artificial marble cured product was brought into contact with hot water at 96 ° C., and the color difference (ΔE) after 100 hours, 200 hours, and 300 hours was measured by Nippon Denshoku Industries Co., Ltd.
It measured using COLORI METER SQ-300H. However, the color difference (ΔE) at each time was evaluated based on the value before contact with hot water. The results are shown in Tables 2 and 3.

Reference Example 1 Vinyl Ester Resin [Product Name: Lipoxy RF-312-7 Showa Highpolymer Co., Ltd.]
Aluminum hydroxide as an inorganic filler in 100 parts
[Product name: Heidilite NB-1 Showa Denko KK
200 parts, 1.5 parts of [trade name: Percure HO Nippon Oil & Fats Co., Ltd.] and 1.0 parts of [trade name: Perloyl TCP Nippon Oil & Fats Co., Ltd.] as a polymerization initiator, and stirred. While degassing with a vacuum pump for 10 minutes. A 9 mm thick spacer is sandwiched between glass plates, a resin solution is poured into the glass plate, the lid is placed, the product is placed in a drier at 80 ° C., left for 180 minutes and then taken out from the drier, and the cured product is cooled with water to room temperature, Then, the glass plate was peeled off, and after standing for 1 day, the hardness of the front and back surfaces of this artificial marble cured product was measured with a Barcol hardness meter (hard). Further, this molded product was visually observed for the presence or absence of coloration and the smoothness of the back surface, and the total light transmittance of the molded product having a thickness of 9 mm was measured by Tokyo Denshoku Co., Ltd. Fully Automatic HAZE.
It was measured using a METER TC-H3DP model.
Further, regarding the boiling test, the back surface of the artificial marble cured product was brought into contact with hot water at 96 ° C., and the color difference (ΔE) after 100 hours, 200 hours, and 300 hours was measured by Nippon Denshoku Industries Co., Ltd. SPECRO COLORIMETER. SQ-
It measured using 300H. However, the color difference (ΔE) at each time was evaluated based on the value before contact with hot water. The results are shown in Tables 2 and 3.

Evaluation of Smoothness The evaluation criteria of smoothness described in Examples 1 to 8, Comparative Examples 2 and 4 and Reference Example 1 are as follows. ◯: The surface is smooth enough to have gloss. Δ: The surface is not glossy but cured. X: The surface has no gloss and is not sufficiently cured.

Contamination resistance test Commercially available Tabasco and color rinse were dropped on the surface of the artificial marbles manufactured by the methods of Examples 1 to 8 and allowed to stand for 1 day, then the Tabasco and color rinse were wiped off, and then the artificial marble was colored. The presence or absence of (stain) was visually evaluated. The results are shown in Table 4.

[0054]

[Table 4]

[0055]

The present invention is characterized by containing a polymerizable unsaturated compound, an inorganic and / or organic filler, and a bisacylphosphine oxide compound of the general formula (1) which is a photopolymerization initiator. Composition for artificial marble,
And pouring the composition into a mold, 400-500 nm
By using a curing method that is characterized by irradiating light having a wavelength of 10 to cure, low productivity, which has been a problem in the conventional casting method using a thermal polymerization initiator, and heating and pressing by a press It is possible to solve the problems of transparency and lack of surface smoothness of a molded product, which have been problems in molding.

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[Procedure amendment]

[Submission date] May 24, 1996

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0015

[Correction method] Change

[Correction contents]

Specific examples of the bisacylphosphine oxide compound of the general formula (1) used in the present invention include bis (2,6-dichlorobenzoyl) -phenylphosphine oxide and bis (2,6-dichlorobenzoyl). −
2,5-Dimethylphenylphosphine oxide, bis (2,6-dichlorobenzoyl) -4-ethoxyphenylphosphine oxide, bis (2,6-dichlorobenzoyl) -4-biphenylylphosphine oxide, bis (2,6 -Dichlorobenzoyl) -4-propylphenylphosphine oxide, bis (2,6-dichlorobenzoyl) -2-naphthylphosphine oxide, bis (2,6-dichlorobenzoyl) -1-naphthylphosphine oxide, bis (2 , 6-dichlorobenzoyl)
-4-chlorophenylphosphine oxide, bis (2,6-dichlorobenzoyl) -2,4-dimethoxyphenylphosphine oxide, bis (2,6-dichlorobenzoyl) -decylphosphine oxide, bis (2,6-di) Chlorobenzoyl) -4-octylphenylphosphine oxide, bis (2,6-dichlorobenzoyl) -2,5-dimethylphenylphosphine oxide, bis (2,6-dichlorobenzoyl) -phenylphosphine oxide, bis (2,2 4,6-Trimethylbenzoyl) -2,5-dimethylphenylphosphine oxide, bis (2,6-dichloro-3,4,5-trimethoxybenzoyl) -2,5-dimethylphenylphosphine oxide, bis (2,6) -Dichloro-3,4,
5-trimethoxybenzoyl) -4-ethoxyphenylphosphine oxide, bis (2-methyl-1-naphthoyl) -2,5-dimethylphenylphosphine oxide, bis (2-methyl-1-naphthoyl) -2,5-phenyl Phosphine oxide, bis (2-methyl-1-)
Naphthoyl) -4-biphenylylphosphine oxide, bis (2-methyl-1-naphthoyl) -4-ethoxyphenylphosphine oxide, bis (2-methyl-)
1-naphthoyl) -2-naphthylphosphine oxide, bis (2-methyl-1-naphthoyl) -4-propylphenylphosphine oxide, bis (2-methoxy-1-naphthoyl) -2,5-dimethylphenylphosphine oxide, bis (2-Methoxy-1-naphthoyl) -4-ethoxyphenylphosphine oxide, bis (2-methoxy-1-naphthoyl) -4-biphenylylphosphine oxide, bis (2-chloro-1-naphthoyl) -2,5- Dimethylphenylphosphine oxide, bis (2,6-dimethoxybenzoyl) -2,
4,4-trimethylpentylphosphine oxide and the like can be mentioned.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0043

[Correction method] Change

[Correction contents]

[0043]

[Table 1]

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Claims (3)

[Claims] 1. A polymerizable unsaturated compound, an inorganic and / or organic filler, and a photopolymerization initiator represented by the following general formula (1):
A composition for artificial marble, which comprises the bisacylphosphine oxide compound of General formula (1); (In the formula, R ^{1 to} R ³ are each independently an alkyl group, an aryl group, an allyl group, an aralkyl group, an alkenyl group, an alkynyl group, a heterocyclic group, a substituted alkyl group, a substituted aryl group, a substituted allyl group, a substituted aralkyl group. Group, substituted alkenyl group, substituted alkynyl group or substituted heterocyclic group) 2. A polymerizable unsaturated compound is used in an amount of 1 to 1000 parts by weight, and a bisacylphosphine oxide compound represented by the general formula (1) is added in an amount of 0.01 to 2.0, based on 100 parts by weight of the polymerizable unsaturated compound. The composition for artificial marble according to claim 1, wherein the composition contains a part by weight. 3. A composition for artificial marble, which comprises casting the composition for artificial marble according to claim 1 or 2 in a mold and then irradiating the composition with light having a wavelength of 400 to 500 nm to cure the composition. Curing method.