JP2017094592A - Method for molding resin molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for molding a resin molding that obtains a resin molding of which a surface having a stripe-like pattern of a base material 2 formed is covered with a surface layer having visible light ray transmissivity, and prevents deformation of the strip-like pattern on the surface of the base material 2 when the surface layer is injection-molded.SOLUTION: A method for molding a resin molding includes: forming a cavity 13 for surface layer formation on the surface side of a base material 2; injecting a resin material into the cavity 13 in a direction A of extension of a stripe-like pattern formed of a large number of recessed grooves 4a; and fluidizing the resin material in the same direction as the extension direction and filling the cavity 13 with the injected resin material to form the surface layer.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a method for molding a resin molded article in which a surface on which a concavo-convex pattern of a substrate is formed is covered with a surface layer having visible light transmittance.

  Various products such as automobile interior materials and exterior materials, household items, and office supplies are molded from synthetic resin. Recently, there is a growing demand for decoration of such resin molded products. Regarding the decorating technique, Patent Document 1 discloses that a transparent texture is formed on the upper surface of a transparent or opaque first synthetic resin film, and a transparent second synthetic resin composed of one or more layers on the texture. Disclosed is a decorative film in which films are laminated.

  Moreover, in patent document 1, when using the synthetic resin which kneaded the flake-like or powdery luster material in the 1st synthetic resin film, when laminating | stacking a 2nd synthetic resin film on a 1st synthetic resin film, The difference in the melt flow rate between the synthetic resins forming the two films is 0.5 to 50 g / min so that the wrinkles are not crushed by heating, the two synthetic resin films may be colored, Since it has glitter, it reflects light well, the reflection of light differs depending on the viewing direction, and the appearance of shadows is different, so that there is a stereoscopic effect and a high-class feeling is described.

JP 2005-14374 A

  By the way, in obtaining a resin molded product obtained by laminating a surface layer having visible light permeability on the surface of the substrate with the concavo-convex pattern formed, when injection molding is adopted for forming the surface layer, the concavo-convex pattern on the surface of the substrate is obtained. There is a problem that it is broken by the injected resin material. That is, for example, when a resin material for surface layer molding is injected in a state where the base material is inserted into the cavity for surface layer molding, the shearing heat generation of the resin material flowing along the surface of the base material in the cavity and the flow thereof The problem is that the unevenness of the uneven pattern is deformed by the shearing force applied to the uneven pattern. Particularly, in the vicinity of the gate of the cavity, since the heat generation and the shearing force continue to be applied to the concavo-convex pattern of the base material until the injection is finished, the concavo-convex pattern tends to collapse.

  The subject of this invention is solving the problem that the uneven | corrugated pattern on the surface of a base material collapse | crumbles by the resin material for surface layers inject | emitted by the cavity.

  In order to solve the above-mentioned problems, the present invention forms a surface layer in a case where a streaky pattern made of a plurality of grooves or ridges extending in a streak pattern is formed as a concavo-convex pattern on the surface of a substrate. The resin material was allowed to flow in a direction extending in the streaky pattern.

The molding method of the resin molded product disclosed here is the surface of the base material on which a streak pattern having a concave-convex height of 5 μm or more and 700 μm or less formed by a plurality of concave grooves or ridges extending in a streak pattern on the surface. Is a method for molding a resin molded article covered with a surface layer having a visible light transmittance of 0.8 mm or more and 8 mm or less,
Forming a cavity for molding the surface layer on the surface side of the base material on which the streak pattern is formed;
Forming the surface layer by injecting a resin material into the cavity,
The resin material is injected into the cavity in a direction extending in a streak pattern of the streaky pattern on the surface of the base material, and flows in the same direction to fill the cavity.

  According to this molding method, since the resin material flows in a direction extending in a streak pattern, the shear force applied from the resin material to the streak pattern is reduced, and the shear stress accompanying the friction with the streak pattern is reduced. The heat generated by shearing is also reduced. Therefore, there is little collapse of the streaky pattern on the surface of the substrate accompanying the injection molding of the surface layer. As a result, the resulting resin molded product clearly shows a streaky pattern on the surface of the substrate through the surface layer with a strong shading and depth (three-dimensional effect), which is advantageous for improving the design.

  Here, when the thickness of the surface layer becomes smaller than 0.8 mm, it becomes difficult to form the surface layer, and when it becomes larger than 8 mm, it becomes difficult to ensure the smoothness of the surface. Further, when the uneven height of the streak pattern is smaller than 5 μm, the visibility of the streak pattern is deteriorated, and when it exceeds 700 μm, it is disadvantageous for forming a fine pattern. It is preferable that the height of the unevenness is 10 μm or more and 350 μm or less.

  In a preferred embodiment of the molding method, the gate of the cavity is a film gate. As a result, when a resin material flows into the cavity from the gate, it is alleviated that a strong shearing force is locally applied to the streak pattern on the surface of the base material, which is advantageous for preventing the streak pattern from collapsing. The film gate preferably has a width of 10 mm or more and a thickness of 0.5 mm or more.

  The film gate is preferably set at a height away from the surface of the substrate in the thickness direction of the substrate. Thereby, the shear heat generation and the shear force applied from the resin material to the streak pattern on the surface of the base material accompanying the injection molding of the surface layer are reduced, which is advantageous for preventing the streak pattern from collapsing.

  The distance between the gate and the substrate surface is preferably 0.5 mm or more. For example, the thickness of the surface layer is 1.5 mm or more, the width of the gate is 15 mm or more, the thickness of the gate is 1.0 mm or more, and the distance between the gate and the substrate surface is 0.5 mm or more. It is preferable that The surface layer thickness is 2.5 mm or more, the gate width is 20 mm or more, the gate thickness is 1.5 mm or more, and the distance between the gate and the substrate surface is 1.0 mm or more. It is preferable that

  It is preferable that one of the opposing surfaces of the film gate is set to be flush with a molding surface for molding the surface of the surface layer of the cavity. It is advantageous to reduce the shear heat generation and the shear force applied from the resin material to the streak pattern on the substrate surface by widening the gap between the gate and the substrate surface.

  Various resin materials can be used for the base material and the surface layer, and as the resin material for the base material, PC (polycarbonate), ABS resin, PC-ABS (polymer alloy of PC and ABS resin), etc. are suitable. As the surface layer resin, PC, PMMA (polymethyl methacrylate resin), or the like can be suitably used.

  It is preferable that the base material contains a bright material and / or an inorganic pigment. Thereby, the melt flow rate of a base material becomes lower than the melt flow rate of the matrix resin itself which comprises this base material. Therefore, when the surface layer is injection-molded, it is advantageous in avoiding the collapse of the streaky pattern of the base material due to the flowing resin material. This means that it is not always necessary to employ a resin material having a melting point lower than that of the matrix resin of the base material as the resin material for the surface layer. Therefore, the selection range of the resin material is expanded.

  As the bright material, for example, aluminum flakes can be used, and as the inorganic pigment, titanium, carbon, iron oxide, or the like can be used.

  According to the present invention, the surface of the base material on which the streak pattern having a concave-convex height of 5 μm or more and 700 μm or less made of a plurality of side-by-side concave grooves or ridges has visible light transmittance. In molding a resin molded article covered with a surface layer having a thickness of 0.8 mm or more and 8 mm or less, a cavity for molding the surface layer is provided on the surface side of the substrate, and the resin for surface layer molding is provided in the cavity Since the material is injected in the direction extending in a streak pattern on the surface of the base material, and flows in the same direction so as to fill the cavity, the uneven surface pattern on the base material surface accompanying the surface injection molding collapses. The resin molded product obtained is reduced, and the uneven surface pattern on the surface of the base material clearly appears with a strong shadow and depth (stereoscopic) through the surface layer, which is advantageous in improving the design.

The perspective view which shows a resin molded product in a partial cross section. The side view which made the partial cross section which shows typically an example of the shaping | molding apparatus of a resin molded product. The perspective view which shows a part of resin molded product released from a metal mold | die. Sectional drawing of a metal mold | die. VV sectional view taken on the line of FIG.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. The following description of the preferred embodiments is merely exemplary in nature and is not intended to limit the invention, its application, or its use.

<Example of resin molded product>
In the resin molded product 1 shown in FIG. 1, 2 is a base material, and 3 is a surface layer covering the surface of the base material 2. A streak pattern 4 is formed on the surface of the substrate 2. Since the surface layer 3 is formed of a resin material having visible light permeability, the streak pattern 4 on the surface of the substrate 2 can be visually recognized through the surface layer 3. The substrate 2 is formed of a resin material containing a bright material and / or an inorganic pigment, and the surface layer 3 is formed of a resin material containing a coloring material or not containing a coloring material. The streaky pattern 4 of the substrate 2 is composed of a large number of concave grooves (or ridges) 4a extending in a straight line, and the height of the concaves and convexes (groove depth) is 5 μm or more and 700 μm or less. The thickness of the surface layer 3 is 0.8 mm or more and 8 mm or less.

<Molding equipment for resin molded products>
FIG. 2 schematically shows an example of the molding device 5 for the resin molded product 1. The molding device 5 is for molding the resin molded product 1 by a two-color molding method.

  In the molding apparatus 5, 6 is a primary cavity mold having a molding surface 6 a for molding the streak pattern of the substrate 2, 7 is a secondary cavity mold having a molding surface 7 a for molding the surface of the surface layer 3, and 8 is both It is a common core mold for the cavity molds 6 and 7. The molding surface 6a of the primary cavity mold 6 is textured to form a streak pattern on the substrate surface.

  Both cavity molds 6 and 7 are arranged on the base 9 so as to face each other with the core mold 8 interposed therebetween, and are movable in a direction away from each other (mold opening direction). The core mold 8 is supported by a rotary 11 that rotates about a vertical axis, and includes a molding surface 8a that molds the back surface side of the base material 2 on both sides that are opposite to each other.

  A base molding cavity 12 is formed by the primary cavity mold 6 and the core mold 8. In addition, a mold 14 that accommodates the base material 2 by the secondary cavity mold 7 and the core mold 8 and forms a cavity 13 for injection molding the surface layer 3 on the surface side of the base material 2 on which the uneven pattern is formed. Is configured. In FIG. 2, 15 is a runner communicating with the base material forming cavity 12, and 16 is a gate of the cavity 12. Reference numeral 17 denotes a runner that communicates with the surface molding cavity 13, and reference numeral 18 denotes a gate of the cavity 13.

  A first injection unit 22 for injecting a first resin material 21 for base material molding is disposed on the back of the primary cavity mold 6. A second injection unit 24 for injecting the second resin material 23 for surface layer molding is disposed on the back of the secondary cavity mold 7. Both the injection units 22 and 24 can be advanced and retracted relative to the cavity molds 6 and 7.

  As schematically shown in FIGS. 3 to 5, the gate 18 of the surface forming cavity 13 is a film gate. In FIG. 3, 19 is a gate portion formed by the gate 16, and 20 is a gate portion formed by the gate 18. The width W of the gate 18 is 10 mm or more, and the thickness T1 of the gate 18 is 0.5 mm or more. The thickness T2 of the surface layer 3 is 0.8 mm or more and 8 mm or less. The gate 18 is set at a height away from the surface of the substrate 2 in the thickness direction (upward) of the substrate 2, and one surface (upper surface) of the opposing surfaces (upper surface and lower surface) of the gate 18 is The surface of the surface of the cavity 13 is flush with the molding surface for molding.

  The gate 18 opens in a direction extending in a streak pattern of the streak pattern 4 of the substrate 2 with respect to the cavity 13. That is, as shown in FIG. 4, the second resin material 23 extends from the gate 18 to the cavity 13 in the direction of the streak pattern 4 on the surface of the substrate 2 (the direction in which the groove 4 a extends) A. And flow in the same direction to fill the cavity 13.

<Method of molding resin molded product>
A method for molding the resin molded product 1 using the molding apparatus 5 will be described. The cavity molds 6 and 7 and the core mold 8 are clamped, the first injection unit 22 is advanced, and the melted first resin material 21 is injected into the base material forming cavity 12. Thereby, the base material 2 which has an uneven | corrugated pattern on the surface is formed. After the mold opening, the core mold 8 is reversed 180 degrees together with the molded base material 2 by the rotary 11, and the mold is clamped. Thereby, a surface layer forming cavity 13 is formed between the surface of the substrate 2 and the secondary cavity mold 7. The second injection unit 24 is advanced to inject the molten second resin material 23 into the surface layer forming cavity 13. Thereby, the surface layer 3 which covers the surface of the base material 2 is formed, and the resin molded product 1 which has an uneven | corrugated pattern in the interface of the base material 2 and the surface layer 3 is obtained.

  In the injection molding of the surface layer 3, the second resin material 23 injected into the cavity 13 from the gate 18 flows in a direction extending in a streak pattern 4 of the base material 2. Therefore, the shear force applied to the streak pattern 4 from the second resin material 23 is reduced, and the shearing heat generated by the shear stress accompanying the friction with the streak pattern 4 is also reduced. Therefore, there is little collapse of the streak pattern 4 on the surface of the base material 2 due to the injection molding of the surface layer 3. As a result, in the obtained resin molded product 1, the streak pattern 4 on the surface of the substrate 2 appears clearly through the surface layer 3 with a strong shading and depth (three-dimensional effect).

  The melting temperature t2 of the second resin material is preferably lower than the melting temperature t1 of the first resin material (for example, the temperature difference (t1-t2) is 0 ° C. or more and 50 ° C. or less). In the injection molding of the base material 2 and the surface layer 3, for example, when PC is used as each matrix resin, the mold temperature may be about 80 ° C. and the cylinder temperatures of the injection units 22 and 24 may be about 250 ° C.

  In the above embodiment, the two-color molding method is adopted for molding the resin molded product. However, the present invention can also adopt an insert molding method in which the base layer is inserted into a mold and the surface layer is injection-molded.

DESCRIPTION OF SYMBOLS 1 Resin molding 2 Base material 3 Surface layer 4 Streaky pattern 4a Groove 5 Molding device 6 Primary cavity type 7 Secondary cavity type 7a Molding surface which shape | molds the surface of a surface layer 8 Core type | mold 18 Gate (film gate)

Claims (7)

The surface of the substrate on which the streak pattern having a concave-convex height of 5 μm or more and 700 μm or less formed of concave grooves or ridges extending in a streak pattern along the surface has a visible light transmittance of 0. A method for molding a resin molded article covered with a surface layer of 8 mm or more and 8 mm or less,
Forming a cavity for molding the surface layer on the surface side of the base material on which the streak pattern is formed;
Forming the surface layer by injecting a resin material into the cavity,
A method for molding a resin molded product, wherein the resin material is injected into the cavity in a direction extending in a streak pattern of the streaky pattern on the surface of the base material, and flows in the same direction to fill the cavity. . In claim 1,
The method for molding a resin molded product, wherein the uneven height of the streaky pattern of the substrate is 10 μm or more and 350 μm or less. In claim 1 or claim 2,
The gate of the cavity is a film gate,
The width of the gate is 10 mm or more, the thickness of the gate is 0.5 mm or more, and the gate is set at a height away from the surface of the substrate in the thickness direction of the substrate. A method for molding a resin molded product. In claim 3,
A method for molding a resin molded product, wherein one of the opposing surfaces of the gate is set to be flush with a molding surface for molding the surface of the surface layer of the cavity. In claim 3 or claim 4,
The thickness of the surface layer is 1.5 mm or more, the width of the gate is 15 mm or more, the thickness of the gate is 1.0 mm or more, and the distance between the gate and the substrate is 0.5 mm or more. A method for molding a resin molded product, comprising: In any one of Claims 1 thru | or 5,
A method for molding a resin molded product, wherein the substrate contains a bright material and / or an inorganic pigment. In claim 6,
A method for molding a resin molded product, wherein the substrate contains aluminum flakes as the glittering material.

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