JPS60149417A - Manufacture of formed part with highly hard surface - Google Patents

Abstract

PURPOSE:To obtain the titled product having a gel coating improved in heat and water resisting properties by a method wherein multifunctional acrylate resin, polyester acrylate resin are applied successively to form a gel coating and core forming material is laminated on the gel coating and hardened. CONSTITUTION:Immediately multifunctional acrylate resin 2 with thickness 100mum or less is applied to the surface of the forming die 1, polyester acrylate resin 3 is applied uniformly to the whole surface so that the sum of thicknesses of the above-said two kinds of resin makes 300mum or less and heated to harden the above-said two kinds of resin and to form the gel coating 4. Core forming material 5 is laminated by hand lay-up of polyester FRP and casting of resin on the surface of the gel coating 4 and hardened, and at the same time, the core forming material 5 and the gel coating 4 are stuck to each other and then removed from the forming die 1 to obtain the desired product.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a method for manufacturing molded products such as bathtubs, counters, wall materials, etc. whose surfaces are formed with high hardness.

[Background technology]

For bathtubs and the like, it is necessary to form a layer of highly hard Gel-2 on the surface of the bathtub in order to improve its scratch resistance.The production of this molded article will be explained using a bathtub as an example. That is, first, FRP is applied by hand lay-up or casting resin is applied on the mold to form a core layer with, for example, an artificial celestial stone (
6), and apply a polyfunctional acrylate resin (7) mixed with a photosensitizer to the surface of this core layer (6) as shown in Figure 1.
7) is photocured by irradiation with ultraviolet rays or electron beams, and a highly hard gel coat layer (8) is formed using the polyfunctional acrylate resin (7). This polyfunctional acrylate resin (7) has a higher resistance to other resins when cured.
As is well known, it is generally used as an ultraviolet curing type or an electron beam curing type. However, when polyfunctional acrylate resin is used as an ultraviolet curing type or an electron beam curing type, special equipment for ultraviolet ray irradiation or electron beam irradiation is required, which increases the equipment cost. In the case of molded products, it is necessary to devise ways to irradiate the polyfunctional acrylate resin with ultraviolet rays or electron beams, resulting in complicated equipment, which also poses the problem of high equipment costs. Furthermore, when ultraviolet irradiation or ray irradiation is performed, there is a problem that there is a risk of explosion if a solvent is used. On the other hand, polyfunctional acrylic resins are anaerobic, and the polymerization inhibiting effect of oxygen may prevent radical polymerization from proceeding, prolong the gel time, or prevent the crosslinking density from increasing. It is well known that this is a major problem when Conversely, it is also known that polyfunctional acrylate resins can be thermally polymerized in a state where air is completely blocked. However, when applying this multifunctional acrylate resin as a gel coat layer to the surface of a molded product, it is not possible to cure it in a state where air is completely blocked, and the adhesion for UV curing is not sufficient, resulting in problems such as bathtubs, etc. When the hot water load is large, there is also the problem that krarif palms tend to enter the Kelcoat layer.

[Purpose of the invention]

The present invention has been made in view of the above points, and is capable of curing polyfunctional acrylate resins in a state where air is completely blocked, and without the need for ultraviolet irradiation or electron beam irradiation. The object of the present invention is to provide a method for manufacturing a molded article with a high surface hardness, which can form a gel coat layer made of resin and can improve the hot water resistance of the gel coat layer.

[Disclosure of the invention]

However, the method for producing a molded article with high surface hardness according to the present invention involves coating the surface of a mold (1) with a polyfunctional acrylate resin (2), and then coating the surface of the polyfunctional acrylate resin (2) with a polyester resin. acrylate resin (3) is applied, and then heated to harden the polyfunctional acrylate resin (2) and polyester acrylate resin (3) to form a gel coat layer (4) composed of two layers of both resins. to form,
A core molding material (5) is then laminated on the surface of this gel coat layer (4) and cured.The present invention will be described in detail below.

First, a mold release agent such as wax or poval is applied thinly and uniformly to the surface of the mold (1), and a polyfunctional acrylic resin (2) is thinly applied to the surface of the mold (1) using a brush or spray. Apply evenly. Polyfunctional acrylate resin (
As 2), any material commonly used for ultraviolet curing can be used. Further, the polyfunctional acrylate resin (2) contains an appropriate amount of a known curing agent or curing accelerator for heat curing. If the coating thickness of polyfunctional acrylic resin (2) is too thick, cracks will occur, so it is preferable to suppress the coating thickness to 100 μm or less. Immediately after applying the polyfunctional acrylate resin (2) in this way, the polyester acrylate resin (3) is further applied uniformly over the entire surface.

The polyester acrylate resin (3) is not particularly limited as long as it is a monofunctional acrylate resin and is heat-curable. Furthermore, ordinary polyester resins can be used in place of this polyester acrylate resin (3), but these resins cannot be expected to improve hot water resistance. The coating amount of the polyester acrylate resin (3) is preferably set so that the total thickness with the polyfunctional acrylate resin (2) is 300 μm or less. In this way, polyester acrylate resin (3)'
Multifunctional acrylate resin (2
) is the mold (1) and polyester acrylate resin (
3) and is completely shut off from the air. Next, the polyfunctional acrylate resin (2) and the polyester acrylate resin (3) are cured by heating. Since the polyfunctional acrylate resin (2) is completely shielded from air, the gelation reaction progresses by heating and it is cured.

When the polyfunctional acrylate resin (2) is thermally cured in this manner, a cured layer having the same level of hardness and scratch resistance as in the case of ultraviolet curing is provided. In this way, the gel foot layer (
4) is formed on the surface of the mold (1), and then a gel coat layer (4) is formed on the surface of the mold (1) by a conventionally well-known method such as polyester FRP hand layer lip or resin casting.
) As shown in FIGS. 2 and 3(a), the core molding material (5) is laminated and cured, and at the same time the core molding material (5) and gel coat layer (4) are bonded together. Then, by removing this from the mold (1), a core layer (6) such as an artificial earth stone-like material obtained by hardening the solid core molding material (5) shown in FIG. 3(b) is formed. A molded article having a high hardness surface is obtained, on which a gel coat layer (4) consisting of two layers of a polyfunctional acrylate resin (2) and a polyester acrylate resin (3) is laminated. The molded product obtained in this way has 1. The gel coat layer (4) is composed of a hardened layer of a polyfunctional acrylate resin (2) and a hardened layer of a polyester-based acrylic resin (3), and both of the ambidextrous layers are made of an acrylic resin. In addition, the cured layer of polyester-based acrylic resin (3) has good adhesion to the core layer (6), which is often formed of polyester resin, and as a result, the gel coat layer (4) and the core layer have good adhesion. layer 6
) can improve the adhesion with.

Next, the present invention will be specifically explained with reference to examples. DPCA-30 (
E1 Ultraviolet curable special acrylate resin manufactured by Honkayaku Co., Ltd.] was applied to a coating amount of 80 μm, and on top of this, isophthalic acid polyester acrylate resin (Yugoriki Co., Ltd.) was applied as a polyester-based acrylic resin. 100
A gel coat layer was formed by applying a coating amount of .mu. thickness and curing the resin by heating. Next, FRP was laid up on the gel coat layer and cured to obtain an FRP molded product whose surface was covered with the gel coat layer.

The surface hardness of this molded product is 7H on a pencil hardness, and no scratches occurred on the surface in the scratch test with #000 steel wool, showing excellent results in terms of surface hardness and scratch resistance. In the test, no blistering, cracking, cracking, peeling, etc. occurred in the gel coat layer, and it showed excellent results in terms of hot water resistance.

〔Effect of the invention〕

As described above, in the present invention, a polyfunctional acrylic V-1 resin is applied to the surface of a mold, and then a polyester acrylate resin is applied to the surface of this polyfunctional acrylate resin, and heated to form a polyfunctional acrylate resin. Since the acrylate resin and polyester acrylate resin are cured to form a gel coat layer, the multifunctional acrylate resin is sandwiched between the mold and the polyester acrylate resin and is completely blocked from air. In addition, polyfunctional acrylate resins can be cured by heating, which eliminates the need for irradiation with ultraviolet rays, which reduces equipment costs, and allows uniform heating even for irregularly shaped molded products. It is possible to easily improve the surface hardness of irregularly shaped articles, and there is less risk of explosion due to solvents, as is the case with ultraviolet irradiation. In addition, the gel coat layer composed of polyfunctional acrylate resin and polyester acrylate resin]
It has good adhesion to the outer layer and can improve hot water resistance.

[Brief explanation of drawings]

Fig. 1 is a Trr side view of a conventional example, Fig. 2 is a sectional view of an embodiment of the present invention, Figs. is the gel coat layer, (5) is the molding material for the core, and (6) is the core layer.

Claims (1)

[Claims] (1) After applying a polyfunctional acrylate resin to the surface of the mold, a polyester acrylate resin is applied to the surface of the polyfunctional acrylate resin, and then heated to combine the polyfunctional acrylate resin and the polyester acrylate resin. A method for manufacturing a molded article with high surface hardness, characterized by curing the above gel coat layer to form a gel coat layer composed of 2M of both resins, and then laminating a core molding material on the surface of this gel coat layer and curing it. .