JPS615910A - Preparation of synthetic resin formed piece excellent in photochromism - Google Patents

Abstract

PURPOSE:To obtain the titled formed piece excellent in photochromism, economic properties, quality, etc. and suitable for lens etc. by injecting synthetic resin into a mold to which a thermoplastic resin sheet having a photochromic skin on one side is stuck. CONSTITUTION:First, the internal surfaces of molds 7, 7' are covered with films or sheets 5 of thermoplastic resin (preferably, polycarbonic resin) having a skin excellent in photochromic properties on one side. Then, synthetic resin material (preferably, of the same kind as the material of the film 5 and having a higher molecular weight) 6 is injected into said molds 7, 7' and said film or sheet 5 and the injected synthetic resin layer 6 are laminated into one body to obtain the desired formed piece 1. Additionally, synthetic resin film containing photochromic agent can be laminated on thermoplastic resin film, for example, etc. to stick photochromic skin to a film etc.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is a method for producing synthetic resin molded products with excellent photochromic properties, and is used for optical parts such as eyeglass lenses, safety equipment such as protective face pieces, vehicles and building materials. It can be used for window glass, greenhouse coverings, etc.

[Conventional technology and its problems]

Synthetic resin molded products have various advantages such as being lightweight, easy to shape, easy to color, rust-free, and high productivity.

In particular, transparent synthetic resin molded products are used for optical parts such as eyeglass lenses, safety equipment such as protective face pieces, window glass for vehicles and building materials, and covering materials for greenhouses.

In these applications, photochromic properties may be required. For example, when the sunlight is strong, the transmission of sunlight is softened to protect the eyes and prevent the temperature rise in the vehicle and the room, and when the sunlight is weak, it remains transparent and transmits as much sunlight as possible. required to do so. In addition, light-shielding protective equipment is required to be colored to block harmful rays when welding sparks are generated during welding work, and to be transparent under normal conditions.

A method of imparting photochromic properties to synthetic resin molded products is to add a photochromic agent to the synthetic resin molded product, but photochromic agents have poor heat resistance and decompose during the extrusion and molding process of the molded product. , deterioration, etc. may occur, resulting in a decrease in photochromic properties, as well as deterioration in the physical properties of the synthetic resin molded product itself, and the disadvantages that the photochromic agent adheres to the mold etc. during molding, resulting in contamination of the mold etc. There is.

On the other hand, there is a method in which a paint containing a photochromic agent is applied to the surface of a synthetic resin molded product and a protective film is formed by baking, but this method improves the photochromic properties, but
Increase in the number of painting processes for painting individual molded products;
Solvents in paint components tend to cause cracks in synthetic resin molded products, resulting in poor appearance and deterioration of physical properties.Also, it is difficult to limit the coating to only the desired areas, which makes product design difficult. There were restrictions on.

[Means for solving problems]

The present invention provides a method for producing synthetic resin molded articles that improves or overcomes the drawbacks of conventional methods.

That is, in the present invention, a thermoplastic film or sheet coated on one side with excellent photochromic properties is mounted in a mold, and then a synthetic resin material is injected into the mold by injection molding, and the film or sheet is coated with a film having excellent photochromic properties. This is a preferable method for producing synthetic resin molded products with excellent photochromic properties, characterized by laminating and integrating a thermoplastic plastic film or sheet coated with a film with excellent photochromic properties on one side and a resin layer formed by injection molding. In implementation, Li uses polycarbonate resin as a plastic film or sheet coated with a film with excellent photochromic properties on one side, and the synthetic resin material used for injection molding is heat-fused with the polycarbonate resin film or sheet during injection molding. It is something to wear.

The manufacturing process is as follows: (1) A thermoplastic plastic film or sheet coated on one side with a film with excellent photochromicity and resilience is punched out into the same shape as the desired part of the synthetic resin molded product to create a punched piece. The process of (2
) attaching the punched piece to a cavity corresponding to a desired part of the mold for the molded product; (3) closing the mold and injecting molten resin at high pressure by injection molding means to form the punched piece and the molded article; This process includes the steps of laminating and integrally molding molten resin, and (4) removing the molded product from the cough mold.It also includes a thermoplastic film or sheet coated with a film with excellent photochromic properties on one side. The process of punching out the same shape as the desired part of the synthetic resin molded product to create a punched piece and the process of attaching it to the cavity corresponding to the desired part of the synthetic resin mold are performed in the process of closing the mold. It consists of things done at the same time.

A thermoplastic plastic film or sheet coated with a photochromic film on one side can be made of thermoplastic plastics such as polycarbonate resin, polycarbonate resin-polybutylene terephthalate resin composition, polymethyl methacrylate (PMMA), acrylonitrile-styrene copolymer. Combined (AS resin), polystyrene,
The normal thickness of transparent plastics such as acetyl cellulose is 100 to 1000. , especially 200-500
．． The film or sheet is coated with a conventionally known method, such as a method of laminating a synthetic resin film containing a photochromic agent, a method of coating a photochromic paint, and then curing it by means such as heat or ultraviolet rays.

An example of the production of a plastic film or sheet with a film with excellent photochromic properties on one side is a polycarbonate resin with a molecular weight of 25.0.
When manufacturing a polycarbonate resin film or sheet by the extrusion T-die method using a polycarbonate resin of 00 or more, a method of thermally laminating the synthetic resin film with a photochromic agent or a method of adhering it using a similar method; extrusion T-die method An acrylate copolymer-based paint containing a photochromic agent is applied to a polycarbonate resin film or sheet produced by a method such as a wire bar method or the like, and then dried by heating.

Next, examples of thermoplastic plastics used in the injection molding of the present invention include those similar to those used for the above-mentioned film or sheet with a photochromic coating.

Here, the plus rank used for films or sheets with a photochromic coating on one side and the thermoplastics used for injection molding are usually the same type in terms of thermal adhesion and optical uniformity. The melt viscosity of the plus rank used for the film or sheet is higher than the melt viscosity of the thermoplastic plastic used for injection molding, that is, it is preferable to use a material with a higher molecular weight. This is more preferable in terms of preventing the sheet from losing its shape. In the case of polycarbonate resin, a film or sheet 1 with a photochromic film formed on one side has a molecular weight of 25.0.
For injection molding, molecular weight of 15,000 to 2
It is better to use one with a value of 5,000.

Note that it is also possible to use different polymers for these thermoplastic plastic films or sheets and for injection molding; in this case,
For the purpose of promoting heat fusion with the thermoplastic resin to be injection molded, and for the purpose of preventing the film from melting and losing its shape due to the resin being injection molded, a primer coat - for example, molding right. It is also a preferable method to apply a paint whose main component is a higher molecular weight substance of the same type as the oil or a heat- or ultraviolet-curable paint to the opposite side of the photochromic coat.

Furthermore, it is also possible to add dyes and pigments, ultraviolet absorbers, infrared absorbers, etc. to films or sheets coated with a photochromic coating on one side, or plastics for injection molding, to give them special properties. be.

Next, in order to facilitate understanding of the present invention, the present invention will be explained using drawings.

FIG. 1 is an example of a perspective view of a synthetic resin molded product which is a faceted lens molded according to the present invention, and FIG. 2 is a sectional view taken along line AA' in FIG. 1. Figure 3 is an enlarged view of section B in Figure 2, in which a thermoplastic film or sheet 5 coated with a photochromic film on one side and a resin layer 6 formed by injection molding of molten resin are laminated and integrated. It is something that Further, FIG. 4 is an explanatory diagram schematically showing the injection molding process according to the present invention, in which a thermoplastic plastic with a photochromic film applied on one side is attached in advance to a 7.7° molding die for a synthetic resin molded product. Film or sheet 5, runner 3, gate 4
It is thermally fused and integrated with the molten resin layer 6 flowing through.

Here, the thermoplastic film or sheet 5 coated with a photochromic film on one side can be easily fixed to the mold cavity using static electricity, suction force such as vacuum, pinning, or other conventionally known methods. I can do it.

Although the above description has been made with reference to drawings, the shape of the synthetic resin molded product of the present invention is not limited to that shown in the drawings, and can take various shapes. It is also one of the preferred embodiments of the present invention that the frame, the mounting portion or fixture, and other functional parts are integrally molded.

〔Example〕

Examples will be explained below.

Example-1 A photochromic paint was coated on one side of an extruded polycarbonate film with a molecular weight of 30,000 and a thickness of 200j by the wire barcode method, and heated at 100°C.
It was dried for 20 minutes to form a photochromic film (
(referred to as film A).

The photochromic paint has a molecular weight of 1 consisting of 80x methyl methacrylate and 20x butyl acrylate.
50,000 acrylate copolymer, 1.5 parts of a spiropyran photochromic agent (manufactured by Nippon Kayaku ■, trade name: Kayaku Luminus C-8), and 85 parts of ethyl cellosolve as a solvent.

Molecular weight 28,000, thickness 500. A polyester primer is applied to a polycarbonate sheet, and then a photochromic sheet (5% ditinone mercury photochromic agent added to acetate resin) is prepared.
(referred to as film B).

The photochromic film-forming film obtained above was first
The molded product was cut out into the shape shown in the figure, and placed in a mold for a molded product having the shape shown in FIG. Then the molecules 1123,000
Polycarbonate resin (PC) was injection molded.

In the obtained molded product, the photochromic film-forming film and the molded paddle part were completely integrated, and no boundary line could be discerned, no matter which film was used. In addition, no tμ scratches or poor appearance of the photochromic film were observed.

[Operation and effect of the invention]

As described above, the present invention provides a synthetic resin molded product that has excellent photochromic properties and is economical and is suitable for optical parts such as eyeglass lenses, safety equipment such as protective face pieces, window glass for vehicles and building materials, and covering materials for greenhouses. It is something that can be provided.

Furthermore, the method for producing a synthetic resin molded article of the present invention includes the following: (1) Since a photochromic film is formed on the surface of the synthetic resin molded article, the photochromic properties can be improved extremely efficiently.

(2) A coating with excellent photochromic properties is applied to one side and the polycarbonate resin film or sheet is heat-sealed and integrated with the molten resin layer in the injection mold, so the desired photochromic properties can be achieved without going through a special painting process. A durable synthetic resin molded product can be obtained, which has excellent productivity and eliminates the occurrence of defects that tend to occur during the painting process.

(3) A coating with excellent soft chrominance and resilience is applied to one side, allowing independent selection of the molecular weight or melt flow value of the synthetic resin used for the polycarbonate resin film or sheet and the resin layer constituting the base of the molded product. Therefore, a highly fluid molding material can be used for the resin constituting the base of the molded article without worrying about cracking or deterioration of physical properties.

etc.

[Brief explanation of drawings]

Fig. 1 is a perspective view of a molded facepiece lens according to an example of the present invention, Fig. 2 is a sectional view taken along line A-A' in Fig. 1, and Fig. 3 is a cross-sectional view taken along line A-A' in Fig. 2.
1 and 4 are partially enlarged schematic diagrams illustrating the state of injection molding of the synthetic resin molded product of the present invention. The numbers in the figure are as follows: 1: molded product, 2: varnish blue, 3: runner, 4: gate, 5: single-sided plastic film, 6:
Molten resin layer 7.7" shows two molds formed by injection molding. Patent applicant: Mitsubishi Gas Chemical Co., Ltd. Representative: Kazuyoshi Nagano

Claims (1)

[Claims] 1. A thermoplastic film or sheet coated on one side with excellent photochromic properties is mounted in a mold, and then a synthetic resin material is injected into the mold by injection molding, A method for manufacturing a synthetic resin molded product with excellent photochromic properties, characterized by laminating and integrating a thermoplastic plastic film or sheet coated with a coating with excellent photochromic properties on one side and a resin layer formed by injection molding. 2. The method for producing a synthetic resin molded article according to claim 1, wherein the plastic film or sheet coated on one side with a film having excellent photochromic properties is a polycarbonate resin. 3. The method for producing a synthetic resin molded product according to claim 2, wherein the synthetic resin material used for injection molding is thermally fused to a polycarbonate resin film or sheet during injection molding. 4. (1) A thermoplastic film or sheet coated with a film with excellent photochromic properties on one side is punched into the same shape as the desired part of the synthetic resin molded product,
(2) attaching the punched piece to a cavity corresponding to a desired part of the mold for the molded article; (3) close the mold and pour the molten resin by injection molding means; Claim 1 comprising a step of laminating and integrally molding the punched piece and the molten resin by high-pressure injection, and (4) taking out the molded product from the mold.
Method for manufacturing synthetic resin molded products described in Section 1. 5. Process of punching out a thermoplastic plastic film or sheet coated with a coating with excellent photochromic properties on one side into the same shape as the desired part of the synthetic resin molded product to create a punched piece and the desired mold for synthetic resin molding. 5. The method of manufacturing a synthetic resin molded product according to claim 4, wherein the step of mounting the molded product in a cavity portion corresponding to the mold portion is carried out at the same time as the step of closing the mold.