JP2002362956A - Artificial marble and method of manufacturing for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide artificial marble with which desired surface smoothness, etc., are easily obtainable by sufficiently lowering the shrinkage rate during curing of a matrix layer and suppressing the occurrence of the sink marks between a pattern material and a gel coat boundary. SOLUTION: This artificial marble is molded to have the gel coat layer on its surface by curing a composition prepared by compounding the pattern material and fillers with a transparent curing resin. The fillers have at least prescribed parts by weight of acicular fillers. The fillers have, for example, 5 to 25 pts.wt. glass fillers and 25 to 50 pts.wt. acicular fillers per 100 pts.wt. transparent curing resin or have 25 to 300 pts.wt. acicular fillers per 100 pts.wt. transparent curing resin. The acicular fillers are formed to a fine powder form of 6 to 26 μm in their fiber size and 35 to 140 μm in their average fiber length.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an artificial marble suitably used for, for example, a bathtub or a bathroom counter and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, as a typical method for producing this kind of artificial marble, a filler such as aluminum hydroxide or a glass filler and a pattern material such as pulverized natural stone or colored particles of synthetic resin are added to unsaturated polyester resin. And a method of curing the same is known. In addition, for the purpose of improving the sense of depth and boiling performance like a bathtub or bathroom counter,
There is also known a method of providing one gel coat (skin) layer on the product surface (for example, see JP-A-59-171612).

[0003]

However, in the case of using a filler such as a pattern material made of ground natural stones or synthetic resin colored particles or a glass filler, the glass filler 14 is filled as shown in FIG. When the resin of the matrix layer 11 hardens and shrinks, shrinkage occurs at the interface 12a of the gel coat layer 12 due to a difference in shrinkage ratio with the particles 13 and the like, and a texture with a smooth surface cannot be obtained. In the case where the pattern material (particles 13) as disclosed in Japanese Patent No. 2809022 is a large particle or the like, there is a problem that this tendency is more likely to be remarkable.

Therefore, in order to solve this problem, the amount of the glass filler 14 added is increased to suppress the shrinkage during curing, or as shown in FIG.
Although it is conceivable to use a low shrinkage agent in combination with No. 5, when increasing the amount of glass filler 14 added, there is a natural limit to the increase, and it is practically difficult to easily obtain the intended appearance. Has been confirmed. When the low-shrinkage agent shown in FIG. 3 is used, although shrinkage of the interface 12a of the gel coat layer 12 can be improved to some extent, it is difficult to suppress the shrinkage to a level that does not cause a problem in appearance, and depending on the type of the low-shrinkage agent. It is practically difficult to easily obtain an artificial marble having the desired surface smoothness, for example, the low-shrinkage agent may become cloudy and cloudy.

Further, it is conceivable to increase the thickness of the gel coat layer 12 or to reduce the shrinkage by forming the gel coat layer 12 as a two-layer structure of a hard layer and a soft layer. Experiments have confirmed that it is difficult to easily obtain artificial marble having the same.
That is, in each of the above-described manufacturing methods, the shrinkage ratio of the matrix layer during curing is determined by measuring the interface between the pattern material and the gel coat layer 12.
Actually, it is difficult to reduce the occurrence of shrinkage to a level that can sufficiently prevent the occurrence of shrinkage.

[0006] The present invention has been made in view of such circumstances, and an object of the present invention is to reduce the shrinkage rate of the matrix layer at the time of curing, and to improve the pattern material. An object of the present invention is to provide an artificial marble in which the occurrence of shrinkage at the gel coat interface is suppressed and the desired surface smoothness and the like can be easily obtained. The object of the invention described in claim 5 is:
Provided is a method for producing an artificial marble in which the shrinkage rate of a matrix layer during curing is sufficiently reduced to suppress the occurrence of shrinkage at an interface between a pattern material and a gel coat, and a desired surface smoothness or the like is easily obtained. It is in.

[0007]

Means for Solving the Problems To achieve the above object, the invention of claim 1 of the present invention provides a method of curing a composition obtained by blending a pattern material and a filler into a transparent curable resin to cure the composition. An artificial marble molded with a gel coat layer, wherein the filler has at least a predetermined part by weight of an acicular filler.

[0008] With this configuration, since the filler compounded in the transparent curable resin has a predetermined part by weight of the acicular filler, the acicular filler reduces the shrinkage rate of the matrix layer during curing. As a result, the occurrence of shrinkage at the interface between the pattern material and the gel coat is suppressed, and artificial marble excellent in surface smoothness and the like can be easily obtained.

The filler is used in an amount of 5 parts by weight based on 100 parts by weight of the transparent curable resin.
A glass filler of about 250 parts by weight and a needle filler of 25 to 50 parts by weight, or 25 to 30 parts by weight based on 100 parts by weight of the transparent curable resin as in the invention of claim 3.
It is preferable to have 0 parts by weight of the needle filler. By configuring in this manner, by using the acicular filler together with the glass filler, it is possible to suppress an increase in the cost of artificial marble, and by using only the acicular filler,
An artificial marble having more excellent surface smoothness and the like can be obtained.

Preferably, the needle-like filler is formed into a fine powder having a fiber diameter of 6 to 26 μm and an average fiber length of 35 to 140 μm. With this configuration, by setting the fiber diameter and the average fiber length to appropriate values, compounding (stirring) with the transparent curable resin can be performed favorably, and more favorable surface smoothness and the like can be obtained. Workability of the molding operation can be improved at the same time.

[0011] The invention according to claim 5 is a method for producing an artificial marble formed by curing a composition obtained by blending a pattern material and a filler with a transparent curable resin and having a gel coat layer on the surface. Then, after forming the gel coat layer on the surface of the mold, the composition having at least a predetermined part by weight of the needle filler as the filler is poured into the mold and cured.

[0012] With this configuration, after a gel coat layer is formed on the surface of the mold by coating, a composition in which a transparent material and a filler having at least an acicular filler are mixed with a transparent curable resin is formed in the mold. Since the material is poured and cured and molded, the shrinkage during curing of the matrix layer is reduced by the needle-shaped filler as a filler, shrinkage at the interface between the pattern material and the gel coat is suppressed, and the surface is smooth. An artificial marble excellent in properties and the like can be easily manufactured.

[0013]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a diagram schematically showing a cross section of an artificial marble according to the present invention. In FIG. 1, artificial marble 1 comprises a matrix layer 2 obtained by curing a composition described later, and a transparent (or translucent) gel coat layer 3 formed on the surface side of the matrix layer 2.
It is composed of

The matrix layer 2 contains a predetermined amount by weight of a muscovite piece 5 as a pattern material, a needle filler 4 and a glass filler 6 as a filler.
Has a maximum particle size of 9 mm on average, for example. The needle-like filler 4 has a fiber diameter of about 6 to 2 for example.
An average fiber length of 35 μm to 5 cm is obtained by grinding 6 μm (preferably about 13 μm) alkali-free E glass.
(Preferably 35 to 140 μm), and the same glass filler 6 as in the past is used.

In this artificial surrogate stone 1, first, a clear gel coat resin is spray-coated at a predetermined thickness t2 (0.2 to 0.6 mm) on the surface of a lower mold on the surface side thereof, and this is cured. Thus, the gel coat layer 3 is formed.
Then, the upper mold is set on the lower mold, and on the gel coat layer 3 in the cavity formed by both molds, a composition obtained by blending a filler and a pattern material (muscovite piece 5) with a transparent curable resin is used. It is molded by pouring (casting) and curing it. When the composition (matrix) is cured, the shrinkage is reduced by the needle-shaped filler 4, and as shown in FIG.
Even when the muscovite piece 5 is located at the gel coat interface 3a, no shrinkage occurs in the gel coat layer 3 and the surface of the artificial marble 1 has good smoothness and the like.

[0016]

EXAMPLE A composition as shown in Table 1 below was prepared, and the composition was cast and cured in a casting mold marked at 10 cm intervals, and the dimension between the marks was measured to determine the shrinkage. Calculated.
At this time, the thickness of the cast product (dimension t1 in FIG. 1) is 10 mm,
The thickness (dimension t2 in FIG. 1) of the gel coat layer 3 is 0.3 mm
The cast product was evaluated for the state after 90 ° C. for 2 hours after curing, and the appearance was visually evaluated. The results are shown in Table 1 below.

[0017]

[Table 1]

From Table 1, it can be seen that the linear shrinkage rate of the example using the needle-like filler 4 as the filler is 0.51%, while the comparative examples 1 and 2 without the needle-like filler 4 are used. In the case of 2, the linear shrinkage is 1.16% and 0.85%,
It became clear that the examples were significantly reduced with respect to Comparative Examples 1 and 2. Also, in the appearance evaluation, in the case of the examples, no generation of surface dulling or white turbidity was observed, and it was confirmed that good surface smoothness was obtained. It is considered that the reason for this is that the use of the acicular filler 4 reduces the shrinkage rate of the matrix layer 2 during curing.

As described above, in the artificial marble 1 of the above embodiment, the short fine powdered needle-like filler 4 is used as a filler.
Is used, the contraction rate of the matrix layer 2 during curing can be reduced, and even when the muscovite piece 5 is located at the gel coat interface 3a, the shrinkage of the gel coat interface 3a due to shrinkage is ensured. In addition, the occurrence of poor appearance such as cloudiness can be prevented, and the artificial marble 1 having the desired surface smoothness and appearance can be easily obtained.

Particularly, the matrix layer 2 is formed by the needle-shaped filler 4.
Therefore, even when a large pattern material such as the muscovite piece 5 is used, the shrinkage at the gel coat interface 3a is suppressed, and the artificial marble 1 having various patterns can be obtained. It can be easily manufactured.

Further, by using the needle filler 4 and the glass filler together, the amount of the needle filler 4 which is relatively expensive at present can be set to an optimum amount, and the desired appearance quality can be suppressed while suppressing the cost increase. The artificial marble 1 can be easily obtained, and by setting the filling amount of the acicular filler 4 to a predetermined amount, the stirring operation at the time of blending into the transparent curable resin can be easily performed, and the uniform blending can be performed. The variation in the shrinkage rate due to the above is suppressed, and more favorable surface smoothness and the like can be obtained, and the stirring operation itself becomes easy, so that the molding cost can be reduced.

In the above embodiment, the glass filler and the acicular filler 4 are used in combination as the filler, but the present invention is not limited to this, and only the acicular filler 4 is used as the filler. You can also. In this case, 25 to 30 parts by weight of the transparent curable resin is 100 parts by weight.
It has been experimentally confirmed that it is preferable to add 0 parts by weight. Further, in the above embodiment, muscovite pieces 5 are used as the pattern material, but it is of course possible to use pulverized materials of various natural stones or synthetic resin colored particles as the pattern material.

[0023]

As described above in detail, according to the first aspect of the present invention, since the filler to be mixed with the transparent curable resin has a predetermined weight part of the acicular filler, the acicular filler forms a matrix. The shrinkage ratio during curing of the layer is reduced, shrinkage at the interface between the pattern material and the gel coat is suppressed, and artificial marble excellent in surface smoothness and the like can be easily obtained.

According to the second aspect of the present invention, in addition to the effect of the first aspect, the filler has a predetermined part by weight of a glass filler and a predetermined part by weight of an acicular filler. Can be set to an optimal amount, and an increase in product cost can be suppressed.

According to the third aspect of the present invention, in addition to the effect of the first aspect of the present invention, since the filler has only a predetermined part by weight of the acicular filler, the artificial material having more excellent surface smoothness and the like is provided. You can get marble.

According to the fourth aspect of the present invention, in addition to the effects of the first to third aspects, the fiber diameter and the average fiber length of the needle-like filler are set to a predetermined value and the needle-like filler is formed into a fine powder. As a result, the needle filler can be favorably compounded into the transparent curable resin, so that better surface smoothness and the like can be obtained, and the workability of the molding operation can be improved at the same time.

According to the fifth aspect of the present invention, after a gel coat layer is formed on the surface of the mold, a filler having a pattern material and at least an acicular filler in a transparent curable resin is formed in the mold. Injection-cured composition is cast and cured for molding.Acicular fillers as fillers reduce the shrinkage rate of the matrix layer during curing, thereby suppressing shrinkage at the interface between the pattern material and the gel coat layer. Therefore, it is possible to easily produce an artificial marble having excellent surface smoothness and the like.

[Brief description of the drawings]

FIG. 1 is a diagram schematically showing a cross section of an artificial marble according to the present invention.

FIG. 2 is a view similar to FIG. 1 of a conventional artificial marble.

FIG. 3 is a view similar to FIG. 1 of another conventional artificial marble.

[Explanation of symbols]

 1 ... artificial marble 2 ... matrix layer 3 ... gel coat layer 3a ... gel coat interface 4 ... ······ Needle filler 5 ······ Mica mica pieces (pattern material) 6 ····· Glass filler

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08K 7/14 C08K 7/14 C08L 67/06 C08L 67/06 // (C04B 26/18 C04B 14:42 B14: 42 14:22 14:22) B29K 101: 10 B29K 101: 10 105: 16 105: 16 B29L 31:10 B29L 31:10 C04B 111: 20 C04B 111: 20 111: 34 111: 34 111: 54 111: 54 F term (reference) 2D032 AB02 4F204 AA41 AB11 AB24 AB25 AD11 AH49 EA03 EA04 EB01 EB22 EF02 EK17 4G052 AB26 AB42 4J002 CF211 DJ056 DL007 FA016 FA067 FA077 GL02

Claims (5)

[Claims] 1. An artificial marble molded with a gel coat layer on the surface by curing a composition obtained by mixing a pattern material and a filler in a transparent curable resin, wherein the filler has at least a predetermined weight. Artificial marble characterized by having needle-like fillers in part. 2. The filler comprises 5-250 parts by weight of a glass filler and 100 parts by weight of a transparent curable resin.
2. The artificial marble according to claim 1, comprising 5 to 50 parts by weight of an acicular filler. 3. The artificial marble according to claim 1, wherein said filler has 25 to 300 parts by weight of an acicular filler per 100 parts by weight of the transparent curable resin. 4. The needle-like filler has a fiber diameter of 6 to 2.
The artificial marble according to any one of claims 1 to 3, wherein the artificial marble is formed into a fine powder having a diameter of 6 µm and an average fiber length of 35 to 140 µm. 5. A method for producing an artificial marble having a gel coat layer on a surface thereof by curing a composition obtained by blending a pattern material and a filler with a transparent curable resin, the method comprising the steps of: A method for producing artificial marble, characterized in that after forming a gel coat layer, the composition having at least a predetermined part by weight of an acicular filler as the filler is poured into the mold and cured.