JPS6127224A - Synthetic resin foamed and molded item excellent in surface gloss and its manufacture - Google Patents

Abstract

PURPOSE:To make it possible to obtain a foamed and molded item whose surface is smooth and excellent in gloss, by monolithically laminating a thermoplastic film or sheet on a foamed resin layer substrate that has been obtained by foam-injection molding a thermoplastic material. CONSTITUTION:A thermoplastic film or sheet is blanked out to produce a blanked piece having the same shape as the desired shape required to the intended molded item. The blanked piece is mounted in a desired part of a cavity of an injection mold with the function film applied desirably to the blanked piece facing outside. Then the molds are closed, and a thermoplastic molding material is injected at high speed by means of foam-injection molding thereby monolithically molding them. Then the molds are opened and the product is removed. Even if the cavity of the mold where the thermoplastic film or sheet is to be placed is not mirror-finished, the product can have enough surface gloss.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a new synthetic resin foam molded product with excellent surface gloss and a method for producing the same, and is applicable to housings for home appliances, office equipment, computers, etc. , and other suitable foam molded products can be provided.

[Conventional method and its problems]

Foamable molding materials include polystyrene (PS), styrene-acrylonitrile copolymer (AS), acrylonitrile-butadiene-styrene copolymer (ABS), polycarbonate (PC), polyester (PES),
Resins such as polyvinyl chloride (PVC), methyl methacrylate (PMMA), polyamide (PA), cellulose acetate (CA), polyethylene (PE), and polypropylene (PP) are used, and nitrogen gas is used as a blowing agent. , inert gases such as carbon dioxide, low boiling point hydrocarbons,
Pyrolytic foaming agents are used.

This type of foam molded product has (1) a light molded product weight, (
2) It is easy to manufacture thick-walled molded products; (3) a structure with a high-density skin part and a low-density central part can be obtained;
(4) It has various features such as cost reduction due to weight reduction, but on the other hand, the appearance of the molded product has countless microscopic bubble holes and unevenness due to foaming gas, and has a rough surface with a glossy finish. The present invention has the following features: - As a result of studying methods for improving the use and functional beauty of foam molded products by giving them a smooth and glossy surface, a completely new method has been used to improve the surface of the foam molded product. They discovered and completed a method to obtain foamed molded products that are smooth and have excellent gloss.

That is, the present invention is a synthetic resin foam molded product with excellent surface gloss, in which a thermoplastic film or sheet and a foam resin layer base formed by foam injection molding of a thermoplastic molding material are laminated and integrated, and preferred embodiments In an embodiment, the thermoplastic film or sheet is coated on one side with one or more functional films selected from the group consisting of hard coating, antifogging, antistatic, antireflection, and heat ray blocking. This is what happens.

The manufacturing method includes (1) punching out a thermoplastic film or sheet into the same shape as the desired part of the molded product to create a punched piece, (2) molding the punched piece into an injection mold. A step of attaching a functional film applied to the punched piece as an outer layer to the cavity portion corresponding to the desired part of the product, (3) closing the mold and foaming injection molding the thermoplastic molding material. (4) opening the mold and taking out the molded product; Even if the mold's mounting cavity of the thermoplastic film or sheet is not mirror-finished, it is possible to obtain a mold with sufficient surface gloss.

The details of the invention will be explained below.

Thermoplastic plastic films or sheets include polycarbonate (PC), polyarylate, polysulfone, and modified polyphenylene ether (modified PPE).
, rubber-modified vinyl aromatic compound copolymers (ABS, M
BS, MASSMMAS, etc.), polyester (PES)
, polycarbonate-polyester resin composition, polyvinyl chloride (PVC), cellulose acetate (CA
), which are made from resins such as
o~i, ooo, preferably 200~500 tnn
It is a material that can be punched and has a higher melt viscosity than the foaming material to be injection molded, which eliminates the occurrence of defects due to deformation due to heat etc. when the injection foaming material is injected. More preferred is a polycarbonate film or sheet. In addition, the functional film to be imparted to the film or sheet as desired can be made by a conventionally known method. In the case of anti-fogging, water-soluble or hydrophilic resins and surfactants are coated with a hard coating agent such as colloidal silica, optionally with one layer of primer, and cured by means such as heat or ultraviolet rays. By coating and curing an anti-fog coating that normally contains an essential component, anti-frost coatings and heat ray blocking coatings can be formed by coating and curing these coatings, or by applying thin films with these functions using vacuum evaporation methods, etc. By forming by means of. In addition, these functional membranes can be used as composite membranes.

Of course, it is also possible to have two or more functions at the same time.

Thermoplastic molding materials for foaming include polystyrene (PS), styrene-acrylonitrile copolymer (AS), in addition to the same materials as the film or sheet materials mentioned above.
), methyl methacrylate (PMMA), polyamide (PA), polyethylene (PE), polypropylene (PP), etc., and these include, in addition to blowing agents,
Materials containing reinforcing materials, inorganic fillers, and other fillers are also suitably used, especially polycarbonate, modified PPE, A
BS is preferred.

Here, the foaming molding material and the thermoplastic film or sheet are usually of the same type, but different types can also be used. For example, when using polycarbonate film or sheet, ABS,
Modified PPE, polyarylate, polysulfone, etc. are examples of materials that can be heat-sealed as they are.

In addition, in the case of injection molded products that have no or insufficient heat fusion properties, it is also preferable to apply a primer coat mainly for the purpose of promoting heat fusion with the injection foam molding resin. The material is not particularly limited as long as it has heat-fusibility with the resin of the foaming molding material, has a higher melt viscosity, and adheres to the plastic film or sheet, and may not be of the same type as the resin for injection molding. These include those mainly composed of higher molecular weight substances and those that are cured by heat and ultraviolet rays. Specifically, when the plastic film or sheet is polycarbonate resin and the foam material for injection molding is PMMA or AS, homo- or copolyacrylate resin solutions, acrylate-based heat- or ultraviolet-curable paints are used. For example, a resin solution of a high molecular weight MMA homopolymer is particularly preferred. Similarly, when the foam material for molding is PS, examples include copolyacrylate and compositions of homo-acrylate and copolyacrylate, and in particular, butyl acrylate <=BA
) etc., and specific examples thereof include high molecular weight MMA/BA copolymers and compositions containing the same. In addition, as a primer coat, a polycarbonate resin film or sheet is laminated with a copolyacrylate film, ethylene-vinyl acetate film (=EV^ film), PMMA, AS, PS, PVC, cellulose film. Suitable for use as a primer for adhesion with resin. Further, depending on the shape of the molded product, the surface to which the film or sheet is attached needs to have a curved surface or a bent portion, and in that case, the film or sheet is used after being appropriately preformed.

Note that it is also possible to impart special functions by adding dyes and pigments, ultraviolet absorbers, infrared absorbers, compounds having photochromic properties, etc. to the resin material of the plastic film or sheet.

〔Example〕

Examples of the present invention are described below.

Example-1 A polycarbonate film with a thickness of 200mm manufactured by the T-die method was punched into a circle with a diameter of 250mm, and this was made into a circular shape with a diameter of 280mm, a plate diameter of 250mm, and a rim height of 15mm. The non-mirror-finished receiver of the mold was attached to the cavity surface of the dish, and then polycarbonate foam molten resin material was injected at high speed using a nitrogen gas foam molding method.

In the resulting tray, the film and the foam molded resin substrate were completely integrated, and the boundary line was not discernible.

In addition, the surface of the film portion of the molded product was smooth and glossy, and the portion without the film had a wood grain appearance, giving the molded product an appearance as if it were made of lacquered wood.

Example-2 Thickness of polycarbonate resin with molecular weight 30,000: 20
Apply an acrylic primer to one side of the extruded film using the wire bar coating method, dry it,
A silicone top coat was then applied using a wire barcode method and cured at 120°C for 1 hour.
- The same procedure as Example 1 was carried out except that this film was used.

In the resulting tray, the film and the foam molded resin substrate were completely integrated, and no boundary line was discernible.

In addition, the surface of the film part of the molded product is smooth and glossy, and has scratch resistance (hardly any scratches were noticed even after rubbing with #0000 steel wool 400 times at a load of 300 g/cd). The part without the film had a woodgrain finish, giving it the appearance of a tray made of lacquered wood.

Example-3 Thickness of polycarbonate resin with molecular weight 28.000: 20
By the wire barcode method on both sides of the 0- film,
An acrylic ply was applied and dried, and then a silicone top coat was applied to one side by wire barcoding and cured at 120°C for 1 hour. (hereinafter referred to as film B).

This film was punched out into a circular shape with a diameter of 250 m, and a pyrolytic foaming agent (
PMMA with 0.5% of azodicarbonamide
Example-
A tray was formed in the same manner as in step 1.

In the resulting tray, the film and the foam molded resin substrate were completely integrated, and no boundary line was discernible.

In addition, the surface of the film part of the molded product is smooth, glossy, and scratch-resistant, and the part without the film has a woodgrain texture, giving it the appearance of lacquered wood. It was Obon.

Example-4 Using a mold with a diameter of 100 m1 + φ, one side of the cavity has a mirror finish and the other side has a rough finish, and a polycarbonate film similar to that in Example-1 is attached to the rough finish mold cavity. Then, the same polycarbonate foam molding material as in Example 1 was injection molded to obtain a disc.

Visually, there was no difference in surface gloss between both surfaces of the obtained disc.

[Operation and effects of the invention]

According to the present invention as described above, the surface is smooth and glossy, has excellent durability, is lightweight, safe, and has scratch resistance, antifogging property, antistatic property, antireflection property, or heat ray blocking property as desired. This makes it possible to provide economical foam molded products, such as cases and housings with excellent surface gloss, and electronic device housings with scratch resistance, antistatic properties, and other properties. This is something we can provide.

Claims (1)

[Scope of Claims] 1. A synthetic resin foam molded product with excellent surface gloss, in which a thermoplastic film or sheet and a foam resin layer base formed by foam injection molding of a thermoplastic molding material are laminated and integrated. 2. The thermoplastic plastic film or sheet is coated with one or more functional films selected from the group consisting of hard coat, antifogging, antistatic, and heat ray blocking on one side. A synthetic resin foam molded article according to claim 1. 3. (1) A process of punching out a thermoplastic film or sheet into the same shape as the desired part of the molded product to create a punched piece, (2) Cutting the punched piece into the desired part of the molded product in an injection mold. (3) closing the mold and molding the thermoplastic molding material at high speed by foam injection molding means; a step of laminating and integrally molding the punched piece and the foamed resin layer substrate by injection; and (4)
) A method for producing a synthetic resin foam molded product with excellent surface gloss, which includes the steps of opening the mold and taking out the molded product. 4. The method for producing a synthetic resin foam molded product according to claim 3, wherein the cavity of the mold for mounting the thermoplastic film or sheet is not mirror-finished. 5. The method for producing a synthetic resin foam molded product according to claim 3 or 4, wherein the thermoplastic film or sheet is coated with a hard coat film on one side.