JPH0350240A - Production of textured translucent artificial marble - Google Patents

Abstract

PURPOSE:To obtain a textured artificial marble excellent in transparency and gloss in good productivity by molding a heterogeneous mixture obtained by mixing a specified composition with a colorant of a hue different from that of the composition and stopping the mixing before they are homogeneously dispersed by a fressurized heating under specified conditions. CONSTITUTION:A heterogenous mixture obtained by mixing a composition comprising an unsaturated polyester resin obtained by dissolving an unsaturated polyester in an ethylenically unsaturated monomer (e.g. styrene), a curing agent (e.g. t-butyl peroxybenzoate), an inorganic filler (e.g. aluminum hydroxide), a three-dimensional styrene polymer of a mean particle diameter <=100mum and a mold release (e.g. zinc stearate) with a colorant of a hue different from that of the composition and stopping the mixing before they are homogeneously mixed is molded by heating at 110-180 deg.C under a pressure >= 10kgf/cm<2>.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention provides a pattern that can be used to mold artificial marble with excellent transparency and gloss and a deep flowing pattern with a high productivity of 1 to 2 degrees. Regarding the manufacturing method of semi-transparent artificial marble.

(Prior Art) There are various materials for housing equipment such as bathtubs, bathtub aprons, counters, washstands, kitchen counters, bathroom walls, etc., such as stainless steel, enamel, holi-floppylene, F, R, P, and molded products. Recently, artificial marble with a particularly beautiful appearance has become popular, and unsaturated polyester resin cast artificial marble has come to be used as a material for housing equipment. For example, as shown in Japanese Unexamined Patent Publication No. 61-233535 δζ, artificial marble has a gel coat layer as the male model number ζ layer of the bathtub, a second layer containing a bleaching filler, and a third layer of resin concrete. It is obtained by a method of forming by spray coating and casting, and after curing at room temperature of 20 to 40°C,
The beef is air-aired at ~80°C. This molding method requires 3 hours of molding time to mold one piece, resulting in poor productivity. To shorten the molding time, it is possible to increase the molding temperature and harden it at, for example, 80 to 180'C, but the thermal stress during molding causes microcracks to occur due to curing shrinkage, making it virtually impossible to manufacture. be. Therefore, as a method to increase productivity and shorten the molding cycle from a few minutes to several tens of minutes, we have developed a molding method using a mold at a high temperature of 100°C or higher, similar to the sheet molding compound method (sMo) and bulk molding compound method (BMC). A possible method is to mold by heating and pressurizing. For example, there is a method shown in Japanese Patent Application Laid-Open No. 52-35249, but even with this method, cracks may occur in the mold depending on the shape of the molded product.
In addition, cracks are likely to occur due to heat shrinkage after demolding. In particular, cracks cannot be prevented in large, deep-drawn molded products such as bathtubs. In order to prevent such defects, for example, Japanese Patent Publication No. 46-14541, Japanese Patent Application Laid-Open No. 50-126059
A method of adding a thermoplastic resin as a low shrinkage agent has been proposed as shown in Japanese Patent Application Laid-Open No. 52-13316. The addition of such a low-shrinkage agent will prevent molding defects such as cracks (the method of heating and pressurizing to obtain translucent artificial marble is a method in which the thermoplastic resin, which is the low-shrinkage agent, is unsaturated polyester). After phase separation and agglomeration as the resin hardens, it further exhibits a low shrinkage effect through thermal expansion and contraction. As a result, fine voids are generated in the unsaturated polyester resin, and the resulting artificial marble becomes extremely transparent. Therefore, it is not possible to obtain a substantially satisfactory translucent artificial marble.In addition, the product is monochromatic and does not have the flow pattern characteristic of marble.

(Problems to be Solved by the Invention) The present invention has been made in view of the above-mentioned drawbacks, and provides a patterned semi-transparent artificial marble with excellent transparency, glossiness, and deep pattern, and excellent productivity. The purpose is to provide a manufacturing method.

(Means for Solving the Problems) The present invention provides an unsaturated polyester resin (λ) obtained by dissolving an unsaturated polyester (,) in an ethylenically unsaturated monomer (b), a curing agent (B), Inorganic filler (C), three-dimensional styrene polymer (D) with an average particle size of 100 #m or less,
and a release agent (B), and a coloring agent (pressure) having a different hue from that of the composition (I) is mixed, and the mixing is stopped before uniform dispersion. Mixture 11
It is characterized by producing patterned translucent artificial marble by heating and pressurizing and molding at 0°C to 180°C and 10 kgr/af1 or more.

The unsaturated polyester (,) used in the present invention includes α,β-unsaturated dibasic acids such as maleic anhydride, fumaric acid, and halogenated maleic anhydride, optionally phthalic acid, phthalic anhydride, halogenated phthalic anhydride, isophthalic acid,
Terephthalic acid, tetrahydrophthalic anhydride, succinic acid,
Saturated dibasic acids such as fumaric acid, adipic acid, sebacic acid, hexahydrophthalic acid and ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1.3--7' ethylene glycol, 2-methylpropanediol, 1. 4-butylene glycol,
1. Obtained by reacting 6-hexanediol, hydrogenated bisphenol, bisphenol, and polyhydric alcohol such as glycol such as adducts of propylene oxide or ethylene oxide, glycerin, trimethylolpropane, etc. . Two or more of these α, β-unsaturated dibasic acids, saturated dibasic acids, and polyhydric alcohols may be used in combination, if necessary. The above unsaturated polyester (
, ) can be produced by conventional synthetic methods.

If necessary in the synthesis, an esterification accelerating catalyst such as dibutyltin oxide, hydroquinone, or
Curing inhibitors such as rosebenzoquinone may also be added.

The unsaturated polyester (I) is dissolved in the ethylene type monomer (b) to form an unsaturated polyester resin.

Examples of the ethylenically unsaturated monomer (b) that can be used in the present invention include styrene, α-chlorostyrene, t-butylstyrene, methyl methacrylate, lower alkyl ester of acrylic acid, lower alkyl ester of methacrylic acid, vinyl Ene, diallyl phthalate, diallyl isophthalate, triallyl cyanurate, triallyl isocyanurate, or an appropriate mixture thereof can be used. In addition, it is preferable that the ethylenically unsaturated monomer (b) be styrene alone or an unsaturated monomer containing at least 80 mol percent of styrene, as this will give good curability and be advantageous for productivity. This is preferable because it gives the artificial marble a good gloss.

The curing agent (B) used in the present invention is prepared using a molding die.
A curing agent suitable for molding by heating and pressurizing at a high temperature of ℃ to 180℃, such as lauroyl peroxide, benzoyl peroxide, t-butylperoxy 2-ethylhexanoate, 2.5-dimethyl 2.5 -di(2ethylhexanoylperoxy)hexane, t-butylperoxylaurate, t-butylperoxybenzoate,
t-butyl peroxylaurate, 1-butyl peroxylaurate, t-butyl peroxybenzony), 2
．． 5-dimethyl-2゜5-di(benzoylperoxy)
Hexanone, t-butyl hydroperoxide, cumene hydroperoxide, P-menthane hydroperoxide, diisopropylbenzene hydroperoxide, dicumyl peroxide, di-1-butyl peroxide, 2,5-dimethyl 2,5-di( t-butylperoxy)hexane, methyl ethyl ketone peroxide, cyclohexanone peroxide, peroxymetal, di-t-butylperoxy 3,3.5)! Organic peroxides such as J methylcyclohexane can be used.

Due to the characteristics of the resulting artificial marble, the curing agent (B) should be added in an amount of 0.5 to 4 parts per 100 parts by weight of the unsaturated polyester resin (A).
It is preferable to use it in a range of 80 parts by weight.

Examples of inorganic fillers that can be used in the present invention include refractive indexes of n, -1, -1. “Magnesium hydroxide of 4, refractive index,
,=1. Magnesium carbonate, refractive index of l*~1.14”
@ “1.” - 1.11 quartz filler (silica)
, refractive index as =1. @@〜1. '1 aluminum hydroxide, refractive index fle = l, deep blue with refractive index ~1.19, calcium sulfate with refractive index no = 1.'' ~11 m5,
Refractive index, =1.11~1. ``Glass powder Glasses such as glass milled fibers and glass flakes can be used, but when selecting them, the refractive index (n#) that is closer to the refractive index (nl) of the cured product of unsaturated polyester resin (mu) is used. It is preferable to select a material having np=a4±0.03, and it is preferable to select a material having np=a4±0.03 so that the decrease in transparency is small (preferably).

The three-dimensional styrene polymer (D) used in the present invention is a low shrinkage imparting agent as disclosed in Japanese Patent Publication No. 1276/1983, and is added for the purpose of reducing curing shrinkage of the unsaturated polyester resin. Although a part of the styrene in the three-dimensional styrene polymer (D) may be appropriately replaced with other vinyl monomers that can be copolymerized with styrene, unsaturated polyester resin (A
When the ethylenically unsaturated monomer (b) in ) is styrene, it is practically preferable to use up to about 20 mol percent in order to sufficiently exhibit the low shrinkage effect of the three-dimensional styrene polymer (D). As these other monomers, those which can be used as the above-mentioned ethylenically unsaturated monomer (b) can be used.

As the crosslinking agent, divinylbenzene derivatives such as divinylbenzene and divinyltoluene, alkylene glycol derivatives such as ethylene glycol dimethacrylate, ethylene glycol, and diacrylate, diallyl phthalate, and the like can be used.

The three-dimensional styrene polymer (D) that can be used in the present invention is:
It is necessary that the crosslinking is sufficient to swell the ethylenically unsaturated monomer (b) in the unsaturated polyester resin, and the crosslinking agent is 0.1 to 5% of the three-dimensional styrene polymer.
．． It is preferable to set it to 0 mol%. Especially styrene 98~
A three-dimensional polymer obtained by copolymerizing 99 mol% and 0.2 to 2.0 mol% of divinylbenzene is preferable because the resulting translucent artificial marble has good transparency, hardness, and dispersibility.

In the present invention, the three-dimensional styrene polymer (D) has a particle size of 100 m or less, which facilitates uniform dispersion (necessary in order to obtain uniform transparency). ) is used to prevent cracks during molding,
In view of the viscosity of the composition for artificial marble and the ease of mixing work, it is preferable that the weight ratio of (human)/(D) is in the range of 10,015 to 40.

Furthermore, the most preferred amount for transparency and gloss is a weight ratio of (A)/(D) of 100/15 to 30. Note that commonly used low-shrinkage agents such as polystyrene and acrylic resin may be added to the extent that they are not practically disadvantageous to the objectives of the present invention, such as transparency, gloss, and productivity.

In the present invention, a mold release agent (I13) is added to the heterogeneous mixture.
It is necessary to use This is because it must be easy to release from the mold in order to directly copy the mirror surface of the mold onto the surface of the artificial marble and to perform molding with good productivity. As the mold release agent (H), for example, stearic acid, calcium stearate, zinc stearate, phosphoric esters, etc. can be used. The content of the mold release agent (B) is determined based on the unsaturated polyester resin (
It is preferable to use 1 to 10 parts by weight per 100 parts by weight of λ).

In addition, in the present invention, if necessary, composition (I) may contain 8MO
Similar to 1BMO, metal oxides such as magnesium oxide,
The handling and mechanical properties of artificial marble are improved by using metal hydroxides such as magnesium hydroxide, thickeners such as polyisocyanates such as 1.4 diphenylmethane diisocyanate, and reinforcing materials such as glass fibers. This is preferable because it improves the performance. It is also possible to use pigments, colorants, hardening modifiers such as hydroquinone and rosebenzoquinone, and inorganic fillers.

Composition (colorants with different hues (l is not particularly limited)
Commercially available pigments such as titanium white, iron gloss, and carbon, and/or toners prepared by dispersing these pigments in resins and plasticizers can be used. In addition, in order to create a deep, celestial-like flowing pattern on the molded product, it is necessary to use a composition that is sufficiently dispersed when mixing wires (
Colorant (It) is added to I) and kneading is stopped before it is uniformly dispersed to form a heterogeneous mixture. The preferred amount of colorant (II) used is such that the weight ratio of (person)/(π) is 100/1 to 1.
There is no particular limit to the kneading machine, but use a double-arm kneader, double planetary mixer, etc. to check the mixing situation and stop kneading before uniformly dispersing the mixture.

The purpose of the present invention is to manufacture patterned semi-transparent artificial marble with excellent transparency and gloss, and a deep pattern with excellent productivity. As a molding method for realizing these excellent properties, it is necessary to mold by heating and pressing at a high temperature of 110 to 180°C and a pressure of 10 kgf/c111 or more. That is, in order to achieve the excellent productivity that is the objective of the present invention, the molding temperature needs to be 110°C or higher, and if it exceeds 180°C, various troubles (
It must be carried out at a temperature of 180° C. or below, as there is a risk of occurrence of pregel, short sheet, burnt molded product, etc. It is preferable to set the molding temperature to 125 to 150°C since there will be no trouble during molding and productivity will be excellent.

The mold is preferably a metal mold that can withstand high temperatures of 110 to 180°C and molding pressure, and the molding pressure is 1
It is assumed to be 0 kgf/ad or more. The surface finish of this mold is such that at least one of the male and female molds, that is, the molding mold that will become the exterior surface of the translucent artificial marble product, is made into a mold with a mirror finish and surface smoothness, and then hard chrome plating is applied. This is preferable because coated products can obtain sufficient transparency and gloss to have commercial value.

There are no particular restrictions on the means for molding by heating and pressurizing, and transfer molding, injection molding, etc. can be used, and press molding is more suitable for producing large-sized translucent artificial marble.

(Examples) Next, the present invention will be specifically explained based on Table 1 using Examples and Comparative Examples.

Parts are by weight.

Method for producing three-dimensional styrene polymer (Example 1) 100 parts of styrene, 3.87 parts of divinylbenzene, 0.01 parts of sodium dotecylbenzenesulfonate, 0.3 parts of benzoyl peroxide, 9 parts of calcium phosphate,
100 parts of water was charged into a paraple flask equipped with a condenser, a stirrer, N, a gas inlet tube, and a temperature and mixed. Polymerization was carried out at 80° C. for about 8 hours. The polymer was washed with water, dehydrated, and vacuum-dried at about 50°C. This was slightly crushed to obtain a three-dimensional styrene polymer (D).

The resulting heterogeneous mixture was molded at a molding pressure of approximately 80 kgf/aa in a 2,000 t press equipped with a hard chrome-plated, mirror-finished bathtub test mold (average bathtub wall thickness: 10 mm) heated to 140°C. The shortest curing time at which demolding was possible was determined by varying the curing time (pressing time). In addition, the bathtubs molded using this mold were visually inspected for cracks, pinholes, etc. to evaluate molding defects. In addition, the male mold heated to 140°C installed in the 50 press was finished with the same mirror finish as above (D 220m
The total light transmittance was determined by molding with a mold for a flat plate of mX 220 mm X 5 mm (thickness) at a molding pressure of approximately 80 kgf/cal.
Glossiness was measured. As a result, a beautiful translucent bathtub was molded without any molding defects. The shortest curing time was 440 seconds. Also, the total light transmittance is 6. ”96, gloss level is 73
A molded product with a beautiful appearance and a deep flowing pattern similar to astronomical stone was produced. The same evaluation method as in Example 1 was used below.

(Example 2) In Example 2, by adding 1 part of magnesium oxide as a thickener to the composition (I) of Example 1, a molded article with even better gloss was obtained and workability was improved.

(Effects of the Invention) According to the present invention, artificial marble having a beautiful pattern, which could only be obtained by low-temperature curing with poor productivity, can be produced at high temperatures with good productivity.

Claims (1)

[Claims] 1. Unsaturated polyester resin obtained by dissolving unsaturated polyester (a) in ethylenically unsaturated monomer (b) (
A), hardening agent (B), inorganic filler (C), average particle size 1
A composition (I) containing a three-dimensional styrene polymer (D) with a diameter of 00 μm or less and a mold release agent (E) is mixed with a colorant (II) having a different hue from that of the composition (I), and uniformly dispersed. Mixing was stopped before mixing, and the resulting heterogeneous mixture was heated to 110
A method for producing patterned semi-transparent artificial marble, which is characterized by molding by heating and pressurizing at 180°C to 180°C and 10 kgf/cm or more.