JPH0482715A - Method for patterning three-dimensional molded product - Google Patents

Abstract

PURPOSE:To mass-produce a three-dimensional molded product having a stable desired pattern or design by setting a surface having a pattern on the side opposite to the molding surface of an injection mold and carrying out performing so as to have the shape conforming to the molding surface of the injection mold and injecting a resin in the injection mold to cure the same. CONSTITUTION:A releasable base material sheet 1 having a desired pattern is positioned so that the surface having the pattern 2 thereof is set on the side opposite to the molding surface of an injection mold 3 and performed into the shape conforming to the predetermined molding surface of the injection mold 3. This performed releasable base material sheet is placed on the molding surface of the injection mold and a resin 4 is injected in the injection mold to be cured. Thereafter, the releasable base material sheet 1 is peeled off. As the injection mold, an FRP mold, a stainless steel mold and an aluminum mold are considered. As the material used in the releasable base material sheet, various resins such as polyethylene terephthalate, polybutylene terephthalate or a copolymer of them are designated and the shape of the mold used in performing is same to that of the injection mold.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for painting a three-dimensional resin molded product, and particularly to a method for painting a three-dimensional molded product that is effective when molding a three-dimensional molded product by pour molding.

[Conventional technology]

Conventionally, as a method of painting and applying patterns to three-dimensional cast molded products such as artificial marble, natural stone powder, colored particles, glitter particles, etc. are mixed into polymeric resin.
A method for expressing paintings such as stone grain patterns, a method for unevenly mixing coloring materials (pigments, dyes) in polymeric resin to obtain marble-like patterns, a method for creating a coloring range different from the base color range, A known method is to mix the ingredients uniformly and then change the pouring direction of the mold during casting to obtain a marble-like pattern. However, in both of these methods, the pattern,
In addition to drawbacks such as difficulty in obtaining patterns stably and insufficient stability of color tone during mass production, the quality of the designs is limited by the skill of the individuals involved. It depends on the level, and it is difficult to stably obtain a uniform product.

[Problem to be solved by the invention]

The present invention eliminates the above-mentioned drawbacks of the conventional painting method for cast molded products, and provides a method for producing three-dimensional molded products by cast molding, which allows desired patterns and designs to be stably obtained in large quantities. The purpose of painting is to obtain a method.

[Means to solve the problem]

In order to solve the above problems, the present invention provides a releasable base material sheet having a desired pattern, with the surface with the pattern located on the side opposite to the mold surface side of the casting mold. Preforming into a shape along a predetermined mold surface, placing the preformed releasable base material sheet on the mold surface of the casting mold, and then injecting a resin into the casting mold and curing it, After that, the releasable base sheet is peeled off.

It is particularly desirable to use a polymeric resin as the resin injected into the casting mold.

In addition, a release layer is formed on the releasable base sheet to facilitate the release of the releasable base sheet from the polymeric resin, and to ensure adhesion between the pattern and the polymeric resin. An easily adhesive primer layer can also be formed on the pattern surface.

Furthermore, for the purpose of protecting the surface of the painting, a surface protection layer made of transparent synthetic resin may be formed on the surface after the base sheet is released from the mold.

The painting method according to the present invention is particularly effective when used for painting decorative artificial marble, but it can also be used for painting many other types of three-dimensional resin products, such as washbasins, bathtubs, etc. be.

The resin used is preferably a polymerizable resin (polymerizable syrup) mixed with pigments, dyes, fillers, polymerization initiators, etc., and should be methyl methacrylate resin and its polymer, or unsaturated polyester resin and its derivatives. is particularly preferred.

As the casting mold used in the present invention, conventionally known molds can be used, such as FRP molds, stainless steel molds, aluminum molds, and epoxy molds.

Materials used for the releasable base sheet include polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene terephthalate/isophthalate copolymers, polyolefin resins such as polyethylene, polypropylene, and polymethylpentene, polyvinyl fluoride, and polyfluoride. vinylidene, polytetrafluoroethylene,
Polyfluorinated ethylene resins such as ethylene-tetrafluoroethylene copolymers, polyamides such as nylon 6 and nylon 6.6, polyvinyl chloride, vinyl chloride/vinyl acetate copolymers, ethylene/vinyl acetate copolymers, ethylene /Vinyl alcohol copolymers, polyvinyl alcohol, vinyl polymers such as vinylon, cellulose resins such as cellulose triacetate and cellophane, acrylic resins such as polymethyl methacrylate, polyethyl methacrylate, and polybutyl acrylate, Single layer or multiple laminates of synthetic resin films or sheets such as polystyrene, polycarbonate, polyester, polyimide, or high-quality paper, thin paper,
Glassine paper, parchment paper, etc. are preferred.

As a means for imparting a pattern to the releasable base sheet, printing means can be used, and advantageous printing methods include intaglio printing such as gravure and gravure offset, letterpress printing such as letterpress and flexography, and lithographic offset. Lithographic printing, stencil printing such as silk screen, die-litho printing, electrostatic printing,
Examples include inkjet printing.

Various molding methods can be used to pre-form a decorative sheet with a desired pattern on a releasable base sheet into a mold having the same shape as a casting mold, such as vacuum molding, vacuum-pressure molding, etc. , press molding, and various other molding means using heat and/or pressure can be used. Moreover, the shape of the mold used for preliminary molding is the same as that of the casting mold.

The ink used for printing is prepared by appropriately mixing a vehicle with coloring agents such as pigments and dyes, extender pigments, solvents, stabilizers, plasticizers, catalysts, curing agents, etc., as necessary. The vehicle is appropriately selected from among thermoplastic resins, thermosetting resins, ionizing radiation-curable resins, etc. depending on the application, required physical properties, printability, etc.

Examples of thermoplastic resins include cellulose derivatives such as ethyl cellulose, cellulose nitrate, cellulose acetate, ethyl hydroxyethyl cellulose, and cellulose acetate brobionate, styrene resins or styrene copolymers such as polystyrene and polyα-methylstyrene, and polymethyl methacrylate. , acrylic resins such as polyethyl methacrylate, polyethyl acrylate, polybutyl acrylate,
Vinyl polymers such as polyvinyl chloride, polyvinyl acetate, vinyl chloride/vinyl acetate copolymer, polyvinyl butyral, rosin, rosin-modified maleic acid resin, rosin-modified phenol resin, rosin ester resin such as polymerized rosin, coumaron resin, vinyl Examples include natural or synthetic resins such as toluene resin and polyamide resin.

Thermosetting resins include phenol resin, urea resin, diallyl phthalate resin, melamine resin, guanamine resin, unsaturated polyester resin, polyurethane resin, epoxy resin, aminoalkyd resin, melamine/urea cocondensation resin, and silicone resin. There are siloxane resins and the like, and to these, crosslinking agents, curing agents such as polymerization initiators, polymerization accelerators, solvents, viscosity modifiers, extender pigments, etc. are added as necessary.

The curing agent is usually an isocyanate, an unsaturated polyester resin, a polyurethane resin, an amine or an epoxy resin, a peroxide such as methyl ethyl ketone peroxide, a radical initiator such as azohisisobutyronitrile, or an unsaturated polyester resin. often used for

As the isocyanate, an aliphatic or aromatic isocyanate having a valence of two or more can be used, and an aliphatic isocyanate is preferable from the viewpoint of prevention of thermal discoloration and weather resistance. Specific examples include tolylene diisocyanate, xylene diisocyanate, 4,4-diphenylmethane diisocyanate, hexamethylene diisocyanate, and redane diisocyanate.

Further, in order to accelerate the curing reaction, heating may be performed after coating, if necessary. For example, in the case of isocyanate-cured urethane-curable unsaturated polyester resins or polyurethane resins, it is usually kept at 40 to 60°C for about 1 to 5 days, and in the case of polysiloxane resins, it is usually kept at 80 to 150°C for 1 to 3 days.
It is about 00 minutes.

It is possible to use an ionizing radiation-curable resin, in which case a composition containing an appropriate mixture of prepolymers, oligomers, and/or monomers having polymerizable non-bonds or epoxy groups in the molecule is used. .

In this case, ionizing radiation refers to electromagnetic waves or charged particle beams that polymerize and crosslink molecules and have L energy quantum.

Pouring, hollow molding, low-pressure injection, or other means may be used to inject the mixed polymeric resin (base resin) into the casting mold.

Further, as described above, the polymerizable resin used in the present invention is preferably a methyl methacrylate resin and its polymer, or an unsaturated polyester resin and its derivative. Acrylic resins include homopolymers of methyl methacrylate and methyl methacrylate and α and β.
Copolymers with ethylenically unsaturated compounds or other polymers of (meth)acrylic acid or its esters may also be used. Examples of monomers constituting the above polymer include vinyl acetate, styrene, methyl (
Meth)acrylate, ethyl acrylate, butyl acrylate, cyclohexyl acrylate, ethyl methacrylate, butyl methacrylate and cyclohexyl methacrylate. As the polyester resin, various types of FRP (FRP) and known ones used in artificial marble may be used. For example, a type containing an α-β unsaturated polybasic acid as one component, modified with any saturated acid and/or unsaturated acid, and dissolved in a monomer with an unsaturated alkyd obtained by an esterification reaction with a polyhydric alcohol. of, or
Bisphenol-based unsaturated polyester resin or isophthalic acid-based unsaturated polyester resin can be used.

The polymerization initiator is commonly used as a catalyst for syrup.
Peroxy compounds, hemibarmaleates (eg mono-tert-butyl peroxymaleate) are suitable.

Curing agents include ethylene dimethacrylate, propylene dimethacrylate, polyethylene glycol dimethacrylate, divinylbenzene, triallyl cyanurate and diallyl phthalate.

Fillers include aluminum hydroxide, magnesium carbonate, barium sulfate, calcium sulfate, alumina, stone powder, and FRP.
Select from waste, silica sand, glass fiber, plastic, kaolin, talc, etc., taking into consideration the impact on aesthetics and product strength.

The present invention achieves the required initial objectives under the above conditions. Furthermore, as described above, in the present invention, if necessary, on the surface of the releasable base sheet where the pattern layer is located, for the purpose of improving the adhesion between the pattern and the polymeric resin that is the base resin layer, By providing a brimer layer made of urethane paint, it is possible to obtain a more stable molded product. Additionally, in order to make it easier to release the releasable base sheet from the molded product, a release layer made of a suitable resin such as butyral resin may be formed on the base sheet, and a pattern may be provided on the release layer. good. Furthermore, after the base sheet is released from the mold, it is also effective to apply a transparent polymeric resin onto the release surface by means such as spray coating to form a surface protective layer for the purpose of protecting the pattern.

[Effects of invention]

According to the present invention, it is possible to mass-produce three-dimensional molded products having stable desired patterns and designs by casting. In addition, since the moldable base material sheet is completely molded in a separate mold before it is attached to the casting mold, it is difficult to prevent wrinkles or tears from forming in the casting mold with complex three-dimensional shapes. It can be installed in a state that perfectly follows the shape, and it is possible to obtain a good-looking final product without leaving any traces of the air intake holes of the vacuum or pressurized molding mold on the molded product.

〔Example〕

In the following, the invention will be explained in more detail according to some embodiments based on the accompanying drawings.

[Example 1] 1. A 2- to 3-μ thick release layer 5 made of butyral resin was provided on a transparent PvC film 1 with a thickness of 150 μ by gravure coating, and a marble pattern 2 was then formed by gravure printing.
was printed. Acrylic resin ink was used as the printing ink.

2. The printed film was molded into the inverse shape of a washbasin bowl using a vacuum molding method.

3.2. The molded film was placed on a stainless steel casting mold 3 having the same shape as the inverted washbowl mold.

4. Furthermore, 3. Base polymerizable resin 4 having the following blending ratio was poured from above by the flow method to a thickness of about 100 to 150 m/m.

A release layer 5 of 2 to 3 μm thick made of butyral resin was provided on 30 parts of silica sand (12 pHR) by gravure coating, and then a marble pattern 2 was printed by gravure printing. A polyester resin ink was used as the printing ink.

2. The printed film was molded into the inverse shape of a washbasin bowl using a vacuum molding method.

3.2. The molded film was placed on a stainless steel casting mold 3 having the same shape as the washbowl inverted mold.

4. Furthermore, 3. Base polymerizable resin 4 having the following blending ratio was poured from above by a flow method to a thickness of about 100 to 150 m/m.

T-Butylvao-neodocanoate
The curing conditions were 70°C for 1 hour and 1120'C for 1 hour after cure.

5. Thereafter, the releasable base sheet was peeled off by normal means.

[Example 2] 1 Transparent PVC film 1 with a thickness of 150μ (Plasticizer Cobalt naphthenate (accelerator) 0.1 parts Methyl ethyl ketone oxide (hardening agent) 0.3 parts Silica sand 50 parts Curing conditions were room temperature ( 20°C) for 12 hours.

5. Thereafter, the releasable base sheet was peeled off by a conventional means.

6. Furthermore, a surface protective layer 7 was formed by spray coating a transparent polymeric resin on the pattern surface.

[BRIEF DESCRIPTION OF THE DRAWINGS] Fig. 1 shows the process of casting a three-dimensional molded product according to the method of the present invention, and Fig. 2 shows a state in which an easily adhesive brimer layer and a release layer are applied to a base sheet. Figures 3 and 3 are views showing a molded product with a surface protective layer applied thereto.

Claims (1)

[Claims] 1. A method for painting a three-dimensional cast molded product, in which a releasable base sheet having a desired pattern is placed so that the surface with the pattern is on the surface of the casting mold. The mold is placed on the opposite side and preformed into a shape that follows a predetermined mold surface of the casting mold, and the preformed releasable base material sheet is placed on the mold surface of the casting mold. A method for painting a three-dimensional resin molded article in a desired manner, the method comprising injecting a resin into a mold and curing it, and then peeling off the releasable base sheet. 2. The painting method according to claim 1, wherein the resin injected into the casting mold is a polymerizable resin.