JPH05285968A - Manufacture of cast molded article - Google Patents

Abstract

PURPOSE:To obtain a non-gel-coated cast molded article excellent in glossiness, smoothness, transparency and resistance to hot water by a method wherein thermal hardening is performed under the condition that the temperature difference is set between the hardening temperature of thermosetting polymer type unsaturated ester resin mortar to the temperature of the female molding surface and that to the temperature of the male molding surface of matching male and female molds. CONSTITUTION:Releasing treatment is applied with releasant to a female and a male molding surface. Next, after matching male and female molds are set, various mortar compositions are prepared. At the pouring of the mortar composition with a pouring device in the matching male and female molds, molds are clamped together by the pressure of about 1kg/cm<2> in order to prevent the mortar composition from leaking through a seal packing. The mortar composition, after being deaerated under vacuum, is poured under pressure in the matching male and female molds so as to be molded under the condition that hot waters, which are controlled to the mold temperatures of the matching male and female molds, are being circulated in the molds. Finally, hardening is performed together with the matching male and female molds at the temperature condition of the male mold so as to obtain an aimed bathtub.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention uses a resin mortar composed of a thermosetting polymerizable unsaturated ester resin and a filler (filler), and does not have a gel coat on the mold surface. The present invention relates to a method for producing a non-gel coat cast molded article having excellent smoothness.

[0002]

2. Description of the Related Art In recent years, resin mortar is like natural stone,
Since heavy-duty molded products with excellent gloss and smoothness are used heavily, sanitary ware, counters, washrooms,
Widely used in bathtubs, wall materials, etc. Many of these molded products are manufactured by applying a gel coat to the mold surface on the surface that is to have gloss and smoothness, and then injecting and curing the resin mortar,
As a result, the appearance of the surface layer is generally maintained and the performance is secured. However, this casting gel coating method has the drawbacks that not only is the process complicated because the gel coating is applied to the mold surface, it is not preferable in terms of environmental hygiene, and blisters that are exposed to hot water for a long period of time occur.

With the widespread use of such cast molding products, in order to obtain molded products of the same quality and with a solid feeling, bulk materials or sheet materials in which a resin and a filler, and in some cases, a fibrous reinforcing material have been blended have been prepared. There is a so-called molding material direction in which a molded product is manufactured by using a molding material and heating and pressurizing it with a mold. However, in the case of this type of molding method,
If the mixing surface is not devised so that a sufficient molding pressure is applied, the desired appearance cannot be obtained uniformly, and therefore the melt viscosity as a molding material must be increased. Therefore, even when air is taken into the molding material to form a molded product, it is often left behind and the yield is worse than expected.

In some cases, there is known a method of incorporating a thermoplastic polymer into a resin mortar for the purpose of achieving a desired appearance and smoothing and reducing shrinkage, but unfortunately, in this case, There is also a constraint that transparency is not obtained as in the conventional casting method.

In order to overcome the drawbacks of the methods of using these molding materials and the methods of compounding the thermoplastic polymer, efforts are being made in the means of applying a gel coat to the desired mold surface. However, when the gel coating is applied, there is a drawback that the same drawbacks as in the above-mentioned cast gel coating method occur. Thus, each of the conventional molding methods has advantages and disadvantages,
It is used properly according to the required performance and application.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to overcome the drawbacks of the conventional method for producing a cast molded article provided with a gel coat layer, and to obtain glossiness and smoothness on the desired front or back surface. To provide a uniformly excellent non-gel coat casting.

[0007]

Means for Solving the Problems The inventors of the present invention have made earnest studies on a method for producing a so-called non-gel-coat cast-molded article which is not gel-coated. Basically, this resin mortar is poured into a mold that will be a combination of male and female, poured and cured by heating, intentionally creating a curing deviation on both mold surfaces under pressure above atmospheric pressure to give the desired appearance. It has been found that the above object can be effectively achieved by increasing the curing temperature of the desired side, for example, the side where smoothness and gloss are desired, to the opposite side.

That is, according to the present invention, when a thermosetting polymerizable unsaturated ester resin mortar is poured into a male / female mating mold and cured by heating to produce a cast molded product, the male / female mating mold has a female mold surface. The present invention relates to a method for producing a cast-molded article, characterized in that a thermosetting polymerizable unsaturated ester resin mortar on the male surface is heated and cured by providing a temperature difference in the curing temperature.

According to the method for producing a cast molded article by the non-gel coat casting method of the present invention, the thermosetting polymerizable unsaturated ester resin mortar compounding viscosity is not as high as the conventional molding material ratio, Air can be sufficiently removed by using a vacuum defoaming machine or the like, and no air residue such as a molded product made from a molding material is generated. In addition, according to the method of the present invention, there is no opacity of the cured product due to the addition of a surface smoothing agent or a low-shrinking agent, which is used in some molding materials. It has a deep marble tone and a ceramic-like finish. Furthermore, if added, the process is simpler as compared to a molded product produced by the cast gel coating method, in which gel coating is applied.Since there is no gel coating, the surface hardness is high and scratches are less likely to occur. , There is no blister even if you touch hot water for a long time.

The merit of applying the gel coat is to improve the appearance and other characteristics. Generally, in the case of a molded article made only of a resin mortar which is not subjected to the gel coat, for example, it is easy to stain, sharpness (texture), and water resistance. Due to the lack of water, there are drawbacks such as devitrification when exposed to hot water for a long time, but it is general that this drawback is improved by applying a gel coat, especially when hot water resistance is required. Can be overcome by selecting the type of unsaturated ester resin, such as vinyl ester resin and a corresponding level of unsaturated polyester resin (for example, bisphenol type polyester resin, neopentyl glycol-isophthalic acid polyester resin, etc.) and fillers. , This feature is very different from the case of using acrylic syrup resin. The details will be described below.

INDUSTRIAL APPLICABILITY The present invention is for producing a non-gel-coated cast molded article, particularly a non-gel-coated cast artificial marble, which is useful for applications such as bathtub, vanity counter, sink counter, sanitary ware, wall material, etc. The present invention relates to a method for producing a molded article suitable for use as the thermosetting polymerizable unsaturated ester resin which is the first component of the artificial marble material, and may be selected depending on the performance depending on the use, particularly vinyl ester resin and polyester. Examples thereof include resins and GMA (glycidyl methacrylate) modified resins, urethane acrylate resins, vinyl ester modified unsaturated polyester resins and the like, and resins having high hot water resistance, transparency and high refractive index are preferable. Two or more of these thermosetting polymerizable unsaturated ester resins may be used in combination.

The filler as the second component of the artificial marble material is usually aluminum hydroxide, aluminum oxide, calcium carbonate, calcium silicate, aluminum, which does not impair the heat resistance and water resistance of the artificial marble molded product. Examples of the powder include calcium acid, silica, talc, zinc oxide, glass powder, and powders such as Fellow Frit [trade name of Nippon Fellow Co., Ltd.], but are not limited thereto. Two or more kinds of these fillers can be used in combination. These fillers may be surface-treated with a silane coupling agent.

The particle size of the filler is preferably 0.5 to 20 μm, more preferably ≧ −10 μm, from the viewpoint of maintaining the gloss and specularity of the non-gel-coated artificial marble molded product. If the particle size exceeds 20 μm, the surface gloss (mirror surface) of the molded product may not be uniform and the appearance may be impaired. If the particle size is less than 0.5 μm, a thermosetting polymerizable unsaturated ester resin mortar paste It is not preferable because it has a high viscosity and causes problems such as difficulty in filling.

The amount of the filler added is not particularly limited, but is 1 with respect to 100 parts by weight of the thermosetting polymerizable unsaturated ester resin.
The amount is preferably from 0 to 220 parts by weight. If it is less than 100 parts by weight, the amount of the resin used increases, resulting in an increase in cost, and the resin and the filler easily separate and settle. This is because if the amount exceeds 220 parts by weight, the viscosity of the resin increases and the workability decreases, and the performance such as strength and the gloss decrease.

When a thermosetting polymerizable unsaturated ester resin mortar is used for molding a bathtub, for example, the bathtub must be beautiful in addition to heat resistance, boiling resistance, transparency (visibility). In order to maintain gloss and smoothness, the filler is surface-treated with a silane coupling agent, for example, aluminum hydroxide, glass powder or the like is surface-treated with a silane coupling agent or the like. From the viewpoint of performance, it is preferable to use such a filler. Further, in the present invention, as the thermosetting polymerizable unsaturated ester resin, a resin having a refractive index closer to that of the filler than a general unsaturated polyester resin, for example, aluminum hydroxide, close to that of glass powder, toughness and By using a light-colored vinyl ester resin that has excellent adhesiveness and is less likely to cause interfacial peeling, transparency and hot water resistance can be greatly improved.

The thermosetting polymerizable unsaturated ester resin mortar of the present invention may optionally contain a dye / pigment, a viscosity reducer, an internal mold release agent, an ultraviolet absorber and the like. The method for polymerizing the thermosetting polymerizable unsaturated ester resin mortar containing the filler of the present invention is not particularly limited, and any suitable method can be used. Examples thereof include a method of heating in the presence of a radical polymerization initiator, a method of using a so-called redox-based catalyst composed of a radical polymerization initiator and an accelerator, and the like.

According to the present invention, a resin mortar composed of a thermosetting polymerizable unsaturated ester resin and a filler is injected into a male-male mating mold, and when the resin is cured by heating, the resin mortar on the female surface and the male surface is cured. A non-gel coat cast molded product that has a difference in temperature and is heat-cured, and one of the front and back surfaces is glossy, has uniform smoothness, and has transparency (vividness) as performance, hot water resistance, and beauty. Is manufactured. By providing a temperature difference between the curing temperatures of the thermosetting polymerizable unsaturated ester resin mortar on the female and male surfaces of the male and female mating type, the gloss blurring due to shrinkage is focused on one side.

The temperature difference of the curing temperature of the thermosetting polymerizable unsaturated ester resin mortar between the female mold surface and the male mold surface may be 20 ° C. or more, but it is 2 in the case of producing a flat plate cast molded product.
0 ° C. or higher, preferably 30 to 55 ° C. is desirable, and in the case of producing a deformed cast molded product (complicated shaped molded product) other than a flat plate, 20 ° C. or higher, preferably 30 ° C. or higher, and more preferably 30 to 55. It is desirable to be in the range of ° C. For example, when the temperature of the desired mold surface is 65 to 95 ° C, the mold temperature on the opposite side is 30 to 45 ° C, preferably the desired mold surface is 80 to 90 ° C, and the temperature is raised stepwise. It may be kept at 80-90 ℃, and the mold temperature on the opposite side is 40-4.
5 ° C is desirable. The temperature difference may be added at the beginning of the polymerization or during the polymerization.

In the present invention, a casting molded article having excellent gloss, smoothness, transparency and hot water resistance can be obtained simply by providing a temperature difference between the curing temperatures of the female mold surface and the male mold surface. When a difference is provided and heat curing is performed under pressure, preferably at a pressure higher than atmospheric pressure to a pressure of 5 kg / cm ^2, a cast molded product having more excellent performance can be obtained. In particular, when producing a deformed cast product, it is necessary to perform it under a pressure of 5 to 5 kg / cm ² which has a curing temperature difference of 30 to 55 ° C. between the female surface and the male surface and is higher than atmospheric pressure. It is desirable for producing an excellent cast-molded article, and in this case, because a low pressure of 5 kg / cm ² or less is expensive, a male and female mating mold is not necessary, and the mold is a resin mold or a metal-plated electrode. Mold, metal spray mold,
Aluminum alloy type is enough.

[0020]

The present invention will be described in more detail with reference to the following examples.

Examples 1 to 10 and Comparative Example 1 A method for producing a bath having a non-gel-coated artificial marble-like appearance using a metal mold of male and female mating mold will be described according to procedures. First, the surface of the male and female molds was subjected to a mold release treatment with a mold release agent (Milla Glaze 88 manufactured by Magfear Co., USA). Next, a male and female mating mold was set (10 mm thick cavity mold), and then various mortar compositions were prepared as shown in Table 1. When the mortar composition was injected into a male and female mating mold with an injection device, the mold was clamped at a pressure of 1 kg / cm ^{2 in} order to prevent the mortar composition from leaking from the seal packing. After defoaming the mortar composition under reduced pressure, the mixture was pressure-fed into a male / female mating mold and molded for 20 minutes while circulating at a water bath temperature adjusted to the male / female mating mold temperature shown in Table 1, and then male and female under male mold temperature conditions. The combined mold was further post-cured for 20 minutes to obtain a bath. The heat curing was carried out under a pressure of 1 kg / cm ^{2 in} Examples 1 to 7 and under atmospheric pressure in Examples 8 to 10. The results are shown in Table 1.

In Example 3, among the Examples, the chopped slant mat was previously provided with the unsaturated polyester resin "Rigolac 158BTN" (Showa High School) in order to reinforce the casting layer in the female mold on the back side of the bathtub. Molecule Co., Ltd.) was laminated with a resin colored white, and the cured reinforcing layer was set in the female mold, and then the male and female mating molds were combined and cast. In addition, in Example 4, the temperature of the male mold on the surface of the bath is raised stepwise from 40 ° C to 20 ° C in 20 minutes.
After holding for a minute, both male and female mating molds were further post-cured for 20 minutes under male mold temperature conditions to obtain a bath.

[0023]

[Table 1]

The components used in Examples 1 to 10 and Comparative Example 1 and the determination of the test results are as follows. (1) Bisphenol-based Riboxy RF-312 manufactured by Showa High Polymer Co., Ltd. (2) Isoneopentyl-based Rigolac G-401 manufactured by Showa High Polymer Co., Ltd. (3) Aluminum hydroxide manufactured by Showa Denko KK ( 4) Fellow frit Nippon Fellow Co., Ltd. (5) Glass powder Nippon Frit Co., Ltd. (6) Kayaku Akzo Co., Ltd. (7) Nippon Oil & Fat Co., Ltd. (8) Cobalt system promotion Agent Showa High Polymer Co., Ltd. (9) Transparency (texture) ◎… very good ○… good △… somewhat inferior (10) Surface gloss (specular) ◎… very good ○… good (11) type Sink due to separation Judgment by visual inspection ◎… No sink on the entire surface ○… Sink on the part ×… Significant sink (12) Whitening by boiling on one side ◎… No change ○… Very slight whitening

As is clear from Table 1, according to the method for producing a cast molded article of the present invention, a non-gel-coated artificial marble having a surface layer having uniform gloss and transparency and excellent hot water resistance can be obtained. Further, by completely curing in the metal mold, there is no need to post-cure after removing from the mold, and it is not necessary to fix it with the deformation preventing support.

[0026]

EFFECTS OF THE INVENTION According to the method of the present invention, it is possible to produce a non-gel coat cast molded article having excellent gloss, smoothness, transparency and hot water resistance.

Claims (4)

[Claims] 1. A male and female mating surface of a male and female mating mold for injecting a thermosetting polymerizable unsaturated ester resin mortar into the male and female mating mold and curing it by heating to produce a cast product. A method for producing a cast molded article, which comprises heat-curing a thermosetting polymerizable unsaturated ester resin mortar with a curing temperature difference. 2. The method for producing a cast molded product according to claim 1, wherein the temperature difference is 20 ° C. or more. 3. The method for producing a cast molded article according to claim 1, wherein the heat curing is performed under a pressure higher than atmospheric pressure. 4. The method for producing a cast molded article according to claim 1, wherein the heat curing is performed under a temperature difference of 20 ° C. or more and a pressure higher than atmospheric pressure.