JP2006240034A - Insert-molded product with dichroic design and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of an insert-molded product with a dichroic design hard to crack, enhanced in production efficiency and excellent in dichroic properties, and the insert-molded product with the dichroic design. <P>SOLUTION: An insert film, which is obtained by providing an adhesive layer 14 on one side of a plastic film 1 to which liquid crystal orientation properties are imparted, is arranged in a mold and, after mold clamping, a molding resin 12 is injected in a molten state to obtain the insert-molded product wherein the insert film and a resin molded product 13 are integrated. After mold opening, a liquefied cholesteric liquid crystal material 3 is applied to the ejected insert-molded product 11 to form a light interference film 4 on the surface of the insert-molded product 11. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing an insert-molded product with a dichroic design and an insert-molded product with a dichroic design used for exterior panels of home appliances.

  In recent years, dichroic appearance designs are attracting attention as decorative designs for exterior panels of home appliances. The dichroic appearance design changes the apparent color appearance depending on the reflection angle, for example, when the reflection angle is 0 °, that is, when viewed from a direction perpendicular to the panel, the reflection angle increases. As it changes, it changes like blue-green, blue, and bluish purple.

As a method of adding this dichroic appearance, generally, (1) a method of forming an optical interference film by laminating inorganic materials such as titanium oxide and silicon oxide on the exterior panel by vapor deposition or sputtering. (2) Separately forming a light interference film made of an inorganic material on the surface of a plastic film, and integrally forming the film on an exterior panel by a so-called insert molding method; (3) Separate plastic film There is a method of forming an optical interference film made of a cholesteric liquid crystal material on the surface of the film and integrally forming the film on the exterior panel by the insert molding method as described above (see Patent Document 1).
JP 2001-277285 A

  However, (1) the method of forming an inorganic optical interference film on the exterior panel, and (2) an inorganic optical interference film is formed separately on the surface of the plastic film and integrated with the exterior panel by the insert molding method. However, since the inorganic thin film has almost no elasticity, there is a problem that when the panel expands and contracts due to changes in temperature and humidity, it cannot follow this and cracks occur. In the method (2), there is a problem that fine cracks are easily generated in the inorganic optical interference film due to the heat and pressure of the molding resin during the insert molding.

  In the method (1), since an inorganic optical interference film is directly formed on the exterior panel, there is a problem that time and labor are required for the vapor deposition and sputtering processes, resulting in poor production efficiency. On the other hand, in the construction method (2), it seems that it is possible to increase production efficiency at first glance by the vapor deposition process in the flow operation with respect to the roll film raw material, but this is not the case. This is because an inorganic optical interference film basically adopts a laminated structure of thin films made of a plurality of different materials, for example, a repeated structure of a thin film of a high refractive index material / a thin film of a low refractive index material. The optical characteristics are determined by the combination of the thicknesses of the layers. Therefore, it is necessary to perform multiple times of vapor deposition and sputtering on the object to be processed, but since the film thickness control is basically not stable in the flow process for the roll film, the desired optical characteristics can be reproduced. Low. As a result, vapor deposition or sputtering is performed on the cut film, so that the production efficiency is inferior as in the case (1).

  In addition, the method of (3) separately forming a cholesteric liquid crystal material optical interference film on the surface of the plastic film and integrating it with the exterior panel by the insert molding method is compared with the method of (1) and (2). In addition, since it is not an inorganic substance, cracks are difficult to occur, and a light interference film can be formed on a roll film by printing or coating at a high speed, so that it is excellent in production efficiency, but conversely, it is inferior to the method (1) (2) is there. That is, the orientation of the optical interference film of the cholesteric liquid crystal material is disturbed by heat and pressure from the molten molding resin during the insert molding, and the color change or density different from the target hue on the appearance is reduced (or There is a problem that damage such as a decrease in reflectance occurs. In addition, the cholesteric liquid crystal material optical interference film stretches and contracts following the film during insert molding, thereby disturbing the orientation of the stretched part and partially reducing the color change or density, that is, causing color unevenness. is there.

  Therefore, the present invention provides a method for producing an insert-molded product with a dichroic design and an insert-molded product with a dichroic design, which solves the above-described problems, is difficult to crack, has high production efficiency, and is excellent in dichroic properties. For the purpose.

  In order to achieve the above object, the method for producing an insert-molded product with a dichroic design according to the present invention arranges an insert film in which an adhesive layer is provided on one side of a plastic film provided with liquid crystal orientation in a molding die. Then, after mold clamping, a molten molded resin is injected to obtain an insert molded product in which the insert film and the resin molded product are integrated, and after the mold is opened, the cholesteric liquefied with respect to the taken out molded product. An optical interference film was formed on the surface by applying a liquid crystal material.

  In the above configuration, the plastic film to which liquid crystal orientation is imparted is a biaxially stretched plastic film.

  In the above configuration, the plastic film to which liquid crystal alignment is imparted is provided with a liquid crystal alignment film on the surface opposite to the side on which the adhesive layer of the plastic film is formed.

  Moreover, in the structure provided with the said liquid crystal aligning film, after apply | coating polyimide resin ink or polyvinyl alcohol resin ink on a plastic film, the liquid crystal aligning film was obtained by rubbing the dry film.

  In the structure provided with the liquid crystal alignment film, the liquid crystal alignment film was obtained by applying an azobenzene photo-alignment film material on a plastic film and then irradiating the coating film with ultraviolet rays.

  Further, the insert molded product with a dichroic design of the present invention has a cholesteric liquid crystal on the surface of an insert molded product in which an insert film provided with an adhesive layer on one side of a plastic film provided with liquid crystal orientation and a resin molded product are integrated. An optical interference film made of a material was formed.

  Since this invention consists of an above-described structure, it has the following effects.

  That is, using an insert film in which an adhesive layer is provided on one side of a plastic film to which liquid crystal orientation is imparted, an insert molded product is obtained by an insert molding method, and then the extracted insert molded product is liquefied. Since the optical interference film is formed on the surface by applying the cholesteric liquid crystal material, it is based on the heating and pressurization to the optical interference film or the follow-up of the optical interference film to the film that has occurred during the insert molding of the method (3). There is no problem. As a result, it is possible to obtain an insert molded product with a dichroic design that is difficult to crack, has high production efficiency, and has excellent dichroic properties.

  Embodiments of the present invention will be described in detail with reference to the drawings.

  1-5 is sectional drawing which shows one Example of the manufacturing process of the insert molded product with a dichroic design based on this invention. In the figure, 1 is a plastic film provided with liquid crystal orientation, 2 is a spray, 3 is a cholesteric liquid crystal material, 4 is a light interference film, 5 is a movable type, 6 is a fixed type, 7 is a cavity forming surface, and 8 is a clamp. A member, 9 is a vacuum suction hole, 10 is a gate portion, 11 is an insert molded product, 12 is a molded resin, 13 is a resin molded product, and 14 is an adhesive layer.

  First, the insert film used in the present invention will be described.

  The insert film used in the present invention is one in which an adhesive layer 14 is provided on one side using a plastic film 1 to which liquid crystal orientation is imparted as a base sheet.

  As the plastic film, it is possible to use a resin sheet such as a polypropylene resin, a polyethylene resin, a polyamide resin, a polyester resin, an acrylic resin, a polyvinyl chloride resin, or a composite of each of the above sheets. it can. The film thickness of the plastic film can be 19 μm to 250 μm. If the film thickness is too thin, handling at the time of insert becomes difficult, and if the film thickness is too thick, if the insert molded product 11 is a thin product, warping occurs due to the difference in thermal shrinkage with the resin molded product 13 after insert molding. It tends to occur.

  In order to impart liquid crystal orientation to the plastic film, the plastic film is biaxially stretched so that the surface has anisotropy, or the surface opposite to the side on which the adhesive layer of the plastic film is formed is liquid crystal. An alignment film is provided. The surface of the stretched film alone has liquid crystal alignment, but finer alignment control is possible if a liquid crystal alignment film is formed on the stretched film.

  The liquid crystal alignment film may be formed by rubbing the dried film with a synthetic fiber after applying an ink made of polyimide resin, polyvinyl alcohol resin or the like on a plastic film. The liquid crystal alignment film may be formed by applying an azobenzene photo-alignment film material on a plastic film and then irradiating the coating film with ultraviolet rays. Examples of the application means include a coating method such as a gravure coating method, a roll coating method and a comma coating method, a printing method such as a gravure coating method and a screen printing method. The dry film thickness of the liquid crystal alignment film is generally 0.1 μm to 5 μm. If the dry film thickness of the liquid crystal alignment film is less than 0.1 μm, the light reflectance of the film is close to zero, so that almost no dichroic appearance effect can be obtained. On the other hand, when the dry film thickness of the liquid crystal alignment film exceeds a certain value, there is no difference in the effect obtained, and even if an expensive liquid crystal alignment film exceeding 5 μm is provided, the cost is increased.

  The adhesive layer 14 is for integrating the insert film with the resin molded product 13. As the adhesive layer, a heat-sensitive or pressure-sensitive resin suitable for the material of the resin molded product 13 is appropriately used. For example, when the material of the resin molded product 13 is an acrylic resin, an acrylic resin may be used. Moreover, when the material of the resin molded product 13 is a polyphenylene oxide / polystyrene resin, a polycarbonate resin, a styrene copolymer resin, or a polystyrene blend resin, an acrylic resin, a polystyrene resin, A polyamide resin or the like may be used. Furthermore, when the material of the resin molded product 13 is a polypropylene resin, chlorinated polyolefin resin, chlorinated ethylene-vinyl acetate copolymer resin, deepened rubber, and coumarone indene resin can be used. Examples of the method for forming the adhesive layer 4 include a coating method such as a gravure code method, a roll coating method, and a comma coating method, a printing method such as a gravure printing method, and a screen printing method. It is also possible to bond an adhesive sheet made of the above-mentioned material by a laminating method or the like to form an adhesive layer.

  In addition, the structure of an insert film is not limited to an above-described aspect. For example, a pattern layer formed by any printing method, coating method, vapor deposition method, or the like may be included between the plastic film 1 to which liquid crystal orientation is imparted and the adhesive layer 14.

  Hereinafter, the manufacturing process of the insert molded product with a dichroic design using the above insert film will be described.

  First, an insert film is placed in a molding die composed of a movable mold 5 and a fixed mold 6 (see FIG. 1), and after mold clamping, a molten molding resin 12 is injected to insert the insert film and the resin molded product. An insert-molded product 11 integrated with 13 is obtained (see FIG. 2). Examples of the molding resin include general-purpose resins such as acrylic resin, polycarbonate resin, ABS resin, and polyamide resin. In FIG. 1, an insert film is set on the surface of the movable mold 5, which is a mold for molding, by a clamp member 8, and the insert film is moved to the movable mold 5 using the vacuum suction holes 9 formed in the movable mold 5. Although the preforming is performed by vacuum suction so as to be along the cavity forming surface 7, the preforming may be performed outside the molding die. In FIG. 2, the gate portion 10 for injecting the molding resin 12 is provided on the fixed mold 6 side. However, the gate portion 10 may be provided on the movable side.

  Next, after cooling, the cholesteric liquid crystal material 3 liquefied is applied to the insert molded product 11 (see FIG. 3) taken out from the molding die by spray 2 (see FIG. 4). Then, the optical interference film 4 is formed (see FIG. 5). As the cholesteric liquid crystal material, liquid crystal materials having various skeletons of main chain type, side chain type, or a composite type exhibiting cholesteric liquid crystal alignment can be used, and these liquid crystal materials have a cholesteric liquid crystal phase in a liquid crystal state. It can be prepared by introducing a chiral component into. Examples of the main chain type liquid crystal material include condensed polymers having a structure in which mesogenic groups composed of aromatic units and the like are bonded, for example, polymers such as polyester, polyamide, polycarbonate, and polyesterimide. Examples of the side chain type liquid crystal material include a polymer having a polyacrylate-based, polymethacrylate-based, polysiloxane-based, or polymalonate-based main chain as a skeleton, and a mesogenic group composed of a cyclic unit or the like in the side chain. The cholesteric liquid crystal material is liquefied by dissolving the cholesteric liquid crystal material in an organic solvent such as methyl ethyl ketone, toluene, or butyl acetate. At this time, the organic solvent is selected so as not to dissolve the plastic film or liquid crystal alignment film as the base. This is because the cholesteric liquid crystal material cannot be aligned when the ground is dissolved by an organic solvent. As the coating means, in addition to the spray coating shown in FIG. 5, dipping, spray coating, silk printing, tampo printing, or the like may be used.

<Example 1>
A biaxially stretched polyethylene terephthalate film having a thickness of 38 μm was used as a base sheet, and a vinyl chloride / vinyl acetate copolymer adhesive layer was formed by gravure printing to a thickness of 1 μm to obtain an insert film.

  Next, the insert film was fixed to the cavity side of the molding die with a clamp, clamped and injected with an acrylic resin, cooled, then opened and taken out to obtain a molded panel.

Next, the polyester cholesteric liquid crystal material is dissolved and diluted with toluene on the surface of the molded panel on which the insert film is integrated, and an ink in which 6% by weight of a radical photopolymerization initiator is mixed is spray-coated. And applied. Then, it was dried by applying hot air at 110 ° C. for 30 seconds and polymerized by irradiation with ultraviolet rays of 600 mj / cm ² .

<Example 2>
A urethane-based adhesive layer was formed to a thickness of 1 μm by gravure printing on a 38 μm-thick polycarbonate film to obtain an insert film. Next, a polyimide resin film is formed to a thickness of 1 μm by microgravure coating on the back side of the adhesive layer forming surface, dried by applying hot air at 130 ° C. for 30 seconds, and applied to a rubbing cloth made of rayon synthetic fiber. A liquid crystal alignment film was formed by rubbing, and the same procedure as in Example 1 was performed except that an insert film was obtained.
According to the above procedure, the method for producing a molded panel having a dichroic design with a cholesteric liquid crystal layer is difficult to crack, has high production efficiency, and is excellent in dichroic properties.

<Example 3>
The photo-alignment film material of azobenzene on the back surface at the micro gravure coating forming surface of the adhesive layer was coated to a thickness of 1 [mu] m, then to this photo-alignment film surface, of 1200 mJ / cm ² through a polarizing filter UV Was performed in the same manner as in Example 2 except that a liquid crystal alignment film was formed and an insert film was obtained.

  The methods for producing a molded panel having a dichroic design by a cholesteric liquid crystal layer as in Examples 1 to 3 were all difficult to crack, had high production efficiency, and were excellent in dichroic properties.

It is sectional drawing which shows one Example of the manufacturing process of the insert molded product with a dichroic design which concerns on this invention. It is sectional drawing which shows one Example of the manufacturing process of the insert molded product with a dichroic design which concerns on this invention. It is sectional drawing which shows one Example of the manufacturing process of the insert molded product with a dichroic design which concerns on this invention. It is sectional drawing which shows one Example of the manufacturing process of the insert molded product with a dichroic design which concerns on this invention. It is sectional drawing which shows one Example of the manufacturing process of the insert molded product with a dichroic design which concerns on this invention.

DESCRIPTION OF SYMBOLS 1 Plastic film provided with liquid crystal orientation 2 Spray 3 Cholesteric liquid crystal material 4 Optical interference film 5 Movable type 6 Fixed type 7 Cavity formation surface 8 Clamp member 9 Vacuum suction hole 10 Gate part 11 Insert molding product 12 Molding resin 13 Resin molding Product 14 Adhesive layer

Claims (6)

  An insert film provided with an adhesive layer on one side of a plastic film imparted with liquid crystal orientation is placed in a molding die, and after mold clamping, the insert film and a resin molded product are injected by injecting a molten molding resin. A dichroic design characterized in that an optical interference film is formed on the surface by applying a liquefied cholesteric liquid crystal material to the inserted insert product after opening the mold. Method for manufacturing insert-molded products.   The method for producing an insert-molded product with a dichroic design according to claim 1, wherein the plastic film to which liquid crystal orientation is imparted is a biaxially stretched plastic film.   2. The production of an insert-molded article with a dichroic design according to claim 1, wherein the plastic film provided with liquid crystal orientation is provided with a liquid crystal orientation film on a surface opposite to the side on which the adhesive layer of the plastic film is formed. Method.   The method for producing an insert-molded article with a dichroic design according to claim 3, wherein the liquid crystal alignment film is obtained by applying a polyimide resin ink or a polyvinyl alcohol resin ink on a plastic film and then rubbing the dry film.   4. The method for producing an insert-molded product with a dichroic design according to claim 3, wherein the liquid crystal alignment film is obtained by applying an azobenzene photo-alignment film material on a plastic film and then irradiating the coating film with ultraviolet rays.   An optical interference film made of a cholesteric liquid crystal material is formed on the surface of an insert molded product obtained by integrating an insert film provided with an adhesive layer on one side of a plastic film with liquid crystal orientation and a resin molded product. An insert molded product with a dichroic design.

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