JP6350491B2 - Molding method of resin molded products - Google Patents

Description

The present invention also relates surfaces uneven pattern of the substrate is formed within the molding how the resin molded article formed is covered with a surface layer having a 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 a surface layer molding die, along with the shear heat generation of the resin material flowing along the surface of the base material in the cavity and the flow thereof In other words, it is a problem of melting damage on the surface of the base material 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.

  The present inventor, through various experiments and research, when the surface layer is injection-molded, one of the causes that the concavo-convex pattern on the surface of the base material is likely to collapse is that when the base material is set in a mold for surface layer molding, It was ascertained that there was a positional shift in the substrate.

  That is, the base material is lifted up without being in close contact with the mold installation surface, and as a result, the cavity clearance between the surface of the base material and the molding surface for molding the surface of the mold is partially Or it is a problem that it becomes narrower than planned over the whole. When the resin material is injected into the cavity in this state, the resin material flows through a narrow clearance even if the base material comes into close contact with the mold installation surface due to the pressure applied from the resin material. Shear heat generation and shearing force applied to the concavo-convex pattern on the surface of the material increase, and the concavo-convex pattern tends to collapse.

  In order to solve the above problem, a protrusion having a height equivalent to the thickness of the surface layer is provided on the molding surface side for molding the surface of the mold, and the protrusion is brought into contact with the surface of the substrate so that the cavity clearance is reduced. It is possible to secure it. However, for example, when a plurality of protrusions are brought into contact with the peripheral edge of the base material at an appropriate interval, when the resin molded product is released, as shown in FIG. The trace is in a state where a notch a is formed in the surface layer 3. For this reason, when a bending force is applied to the resin molded product 1, stress concentrates on the portion of the notch “a”, which becomes the starting point of destruction.

  Therefore, in order to solve the above-described problems, the present invention provides a protrusion on the substrate side to ensure the clearance of the cavity.

The molding method of the resin molded product disclosed herein is such that the surface of the base material on which the unevenness pattern having an unevenness height of 5 μm or more and 700 μm or less is formed has a thickness of 1.5 mm or more and 8 mm with visible light transmittance A molding method of a resin molded product covered with the following surface layer,
Forming a cavity for molding the surface layer on the surface side of the base material on which the concave and convex pattern is formed, using a mold;
Forming the surface layer by injecting a resin material into the cavity,
The base material contains a bright material and / or an inorganic pigment,
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;
Providing a protrusion with a height comparable to the thickness of the surface layer on the surface side of the substrate,
In the step of forming the cavity, the protrusion is brought into contact with the molding surface side for molding the surface of the surface layer of the mold, whereby the thickness of the surface layer is set between the surface of the substrate and the molding surface. It is characterized by ensuring comparable clearance.

  According to this molding method, when the mold is clamped, the protrusion provided on the surface side of the base material comes into contact with the molding surface side for molding the surface of the mold surface, so that the surface between the surface of the base material and the molding surface is provided. Clearance comparable to the thickness of the surface layer is secured. Therefore, when the resin material is injected into the cavity, the shear heat generation and the shear force applied to the concavo-convex pattern on the substrate surface are not increased, which is advantageous for preventing the concavo-convex pattern from collapsing. Therefore, the resulting resin molded product clearly shows a concavo-convex pattern on the surface of the substrate through the surface layer with a strong shadow and depth (three-dimensional effect), which is advantageous for improving the design. Further, since the protrusions are provided on the base material side, the protrusions remain on the resin molded product even after the resin molded product is released, and the resin molded product cannot be notched as a starting point for destruction.

Here, when the thickness of the surface layer becomes smaller than 1.5 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.

  Moreover, when the uneven height of the uneven pattern is smaller than 5 μm, the visibility of the uneven 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.

By the gate of the upper crisis Yabiti is a film gate, is alleviated that locally high shearing force to the concave and convex pattern of the substrate surface when the resin material flowing from the gate to the cavity is applied, uneven It is advantageous for prevention of pattern collapse. The film gate preferably has a width of 10 mm or more and a thickness of 0.5 mm or more.

In addition, the film gate is set at a height away from the surface of the base material in the thickness direction of the base material, so that it is added to the concavo-convex pattern on the base material surface from the resin material along with the injection molding of the surface layer. The shear heat generation and the shear force are reduced, which is advantageous for preventing the uneven pattern from collapsing.

The distance between the gate and the substrate surface is preferably 0.5 mm or more. For example, the width of the upper Kige and reports open and above 15 mm, the thickness of the gate as above 1.0 mm, distance between the gate and the substrate surface is preferably not less than 0.5 mm. When the thickness of the surface layer is 2.5 mm or more, the width of the gate is 20 mm or more, the thickness of the gate is 1.5 mm or more, and the distance between the gate and the substrate surface is 1. It is preferable to be 0 mm or more.

When the base material contains a bright material and / or an inorganic pigment, the melt flow rate of the base material becomes lower than the melt flow rate of the matrix resin itself constituting the base material. Therefore, when the surface layer is injection-molded, it is advantageous in avoiding the concavo-convex pattern of the base material from collapsing 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.

  In preferable embodiment of the said shaping | molding method, the said processus | protrusion is provided in the peripheral part of the said base material. Thereby, it can be avoided that the protrusions remaining on the resin molded article hinder the visual recognition of the concavo-convex pattern on the substrate surface. In addition, this invention does not exclude that protrusion is provided in the center part of a base material.

  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 concavo-convex 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.

According to the present invention , the surface of the base material on which the uneven pattern having an uneven height of 5 μm or more and 700 μm or less is covered with a surface layer having a visible light transmission thickness of 1.5 mm or more and 8 mm or less. In molding a resin molded product, in the step of forming a cavity for molding the surface layer on the surface side of the base material, a protrusion having a height comparable to the thickness of the surface layer is provided on the surface side of the base material. By making the protrusions of the base material abut on the molding surface side that molds the surface of the mold, a clearance equivalent to the thickness of the surface layer is secured between the surface of the base and the molding surface , and the base The material contains a bright material and / or an inorganic pigment, the gate of the cavity is a film gate, the width of the gate is 10 mm or more, the thickness is 0.5 mm or more, and the gate extends from the surface of the substrate to the substrate. Height away in the thickness direction Because set to, collapse of uneven pattern of the substrate surface when injecting a resin material into the cavity is reduced, the resulting resin molded article, a strong shadow sense uneven pattern of the substrate surface through the surface layer and the depth feeling (stereoscopic It appears clearly with a sense of sensation), which is advantageous in improving the design properties, and the resin molded product cannot be cut out as a starting point of destruction, which is advantageous in terms of strength.

The perspective view of a resin molded product. The expansion perspective view which made the resin molded product 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. FIG. 6 is a sectional view taken along line VI-VI in FIG. 4. The perspective view of a primary molded product. Sectional drawing of the metal mold | die which shape | molds a primary molded product. Sectional drawing of the metal mold | die which shape | molds a resin molded product using a primary molded product. The perspective view of the resin molded product shape | molded by providing a processus | protrusion on the metal mold | die side.

  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 bank-shaped protrusion 2 a comparable to the thickness of the surface layer 3 is formed on the peripheral edge of the base material 2 on the surface side (surface layer 3 side). As shown in an enlarged view in FIG. 2, an uneven 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 uneven 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 uneven height of the uneven pattern 4 of the substrate 2 is 5 μm or more and 700 μm or less, and the thickness of the surface layer 3 is 1.5 mm or more and 8 mm or less.

<Molding equipment for resin molded products>
FIG. 3 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 concavo-convex 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 cavities. It is a common core type for molds 6 and 7. The cavity surface 6a of the primary cavity mold 6 is textured to form a concavo-convex 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. The base material forming cavity 12 of this example has a protrusion forming portion 12a for forming the protrusion 2a of the base material 2 on the peripheral edge portion. The secondary cavity mold 7 and the core mold 8 constitute a mold 14 that accommodates the base material 2 and forms a cavity 13 for injection molding the surface layer 3 on the surface side of the base material 2 on which the concavo-convex pattern is formed. Is done. In FIG. 3, 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. 4 to 6, the gate 18 of the surface forming cavity 13 is a film gate. In FIG. 4, 19 is a gate portion formed by the gate 16 of the base material forming cavity 12, and 20 is a gate portion formed by the gate 18 of the surface layer forming cavity 13.

The width W of the gate 18 is 5 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 1.5 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 distance S between the gate 18 and the surface of the substrate 2 is preferably 0.5 mm or more. For example, when the thickness T2 of the surface layer 3 is 1.5 mm or more, the width W of the gate 18 is 15 mm or more, and the thickness T1 of the gate 18 is 1.0 mm or more. The interval S is preferably 0.5 mm or more. Further, when the thickness T2 of the surface layer 3 is 2.5 mm or more, the width W of the gate 18 is 20 mm or more, the thickness T1 of the gate 18 is 1.5 mm or more, and the gate 18 and the surface of the substrate 2 are The interval S is preferably set to 1.0 mm or more.

  When the width W of the gate 18, the thickness T1 of the gate 18, and the thickness T2 of the surface layer 3 are each expressed in mm, the index value K = W × T1 × T2 for preventing the collapse of the uneven pattern is 60 or more. More preferably, the index value K is 90 or more, and the index value K is more preferably 120 or more.

<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 and the protrusion 2a was provided in the peripheral part 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. In this clamping, as shown in FIG. 6, the protrusion 2 a at the peripheral edge of the base 2 abuts against the molding surface 7 a side of the secondary cavity mold 7, thereby preventing the base 2 from being lifted from the core mold 8. Is done. Thereby, a clearance comparable to the thickness T <b> 2 of the surface layer 3 is ensured between the surface of the substrate 2 and the molding surface 7 a of 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.

  As described above, the second resin material 23 is injected into the cavity 13 in a state in which a clearance equivalent to the thickness T2 of the surface layer 3 is secured between the surface of the substrate 2 and the molding surface 7a. The heat generation and the shearing force applied to the concavo-convex pattern on the surface of the surface are not increased, which is advantageous in preventing the concavo-convex pattern from collapsing. Therefore, in the obtained resin molded product 1, the concavo-convex 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), which is advantageous for improving the design. Further, since the protrusion 2a is provided on the base material 2 side, as shown in FIG. 1, the protrusion 2a remains on the resin molded product 1, and the resin molded product 1 has a notch that is a starting point of destruction. Can not.

  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.

<Primary molded product used for molding of resin molded product>
FIG. 7 shows a primary molded product 31 used for molding the resin molded product 1 shown in FIG. The primary molded product 31 is integrally connected to the base material 2 having a concavo-convex pattern 4 on the surface, a protrusion 2 a protruding from the peripheral edge of the base material 2 to the surface side of the base material 2, and a base 2. And a resin gate portion 19.

  The base material 2, the protrusion 2a, and the gate portion 19 are integrally formed of the same resin material, and the surface of the base material 2 and the surface of the resin gate portion 19 are flush with each other. The protrusion 2a is formed at a height comparable to the thickness (0.8 mm or more and 8 mm or less) of the surface layer 3 shown in FIG. The uneven height of the uneven pattern 4 is 5 μm or more and 700 μm or less, preferably 10 μm or more and 350 μm or less. The base material 2 contains a bright material and / or an inorganic pigment, and preferably contains aluminum flakes as the bright material.

  The primary molded product 31 can be formed by injection molding using a mold 32 shown as an example in FIG. In FIG. 8, reference numeral 33 denotes a fixed mold, and 34 denotes a movable mold. The fixed mold 33 and the movable mold 34 form a cavity 12, a runner 15, and a gate 16 for molding the substrate 2. A protrusion forming portion 12 a for forming the protrusion 2 a is formed at the peripheral edge of the cavity 12. A resin gate 19 is formed by the gate 16.

  As shown in FIG. 9, the primary molded product 31 is inserted into a mold 14 for molding a resin molded product. In FIG. 9, 41 is a fixed type and 42 is a movable type. The primary molded product 31 is inserted into the fixed mold 41, the surface layer molding cavity 13 is formed by the base material 2 and the movable mold 42, and the gate 18 is formed by the resin gate 19 and the movable mold 43. When the protrusion 2 a comes into contact with the movable mold 42, a clearance equivalent to the thickness of the surface layer 3 is secured between the surface of the base 2 and the molding surface 42 a of the movable mold 42 that molds the surface of the surface layer 3.

  When the resin material for surface layer molding is injected into the mold 14, when the resin material flows from the runner 17 formed by the fixed mold 41 and the movable mold 42 into the gate 18 having the resin gate portion 19, a part of the flow path surface. The material changes from metal to resin, which causes a disturbance in the flow of the resin material. The disturbance of the flow is settled as the resin material flows through the resin gate portion 19.

  When the resin material flows into the cavity 13 from the gate 18, the resin gate portion 19 of the gate 18 and the base material 2 of the cavity 13 are made of the same resin, so that a new flow disturbance is caused due to the change of the material. There is nothing. Accordingly, the resin material flows from the surface of the resin gate portion 19 onto the surface of the base material 2 in a state where the flow disturbance is subsided.

  Further, the protrusion 2 a prevents the base material 2 from floating from the fixed mold 41, and a clearance equivalent to the thickness of the surface layer 3 is ensured between the surface of the base material 2 and the molding surface 42 a of the movable mold 42. Further, the shear heat generation and the shear force applied to the uneven pattern 4 on the surface of the substrate 2 do not increase.

  As described above, the flow of the resin material is less disturbed, and the heat generation and the shearing force applied to the concavo-convex pattern 4 on the surface of the substrate 2 are not increased, so that the concavo-convex pattern 4 can be avoided from collapsing. As a result, the resulting resin molded product clearly appears with a strong shadow and depth (three-dimensional effect) on the surface of the substrate through the surface layer having visible light permeability.

  In addition, although embodiment shown in FIGS. 7-9 is an example which takes one resin molded product, many pieces can also be taken like 2 pieces shown in FIG.

  In each embodiment of the two-color molding and the primary molded product, the circumferentially continuous protrusions are provided on the peripheral edge of the base material. However, a plurality of protrusions may be provided at intervals in the circumferential direction. .

DESCRIPTION OF SYMBOLS 1 Resin molding 2 Base material 2a Protrusion 3 Surface layer 4 Concavity and convexity 5 Molding device 6 Primary cavity type 7 Secondary cavity type 7a Molding surface 8 Core type 13 Surface layer forming cavity 14 Mold 18 Gate 31 Primary molding product 42a Molding surface

Claims (6)

A resin molded product in which the surface of a substrate having a concavo-convex pattern with a concavo-convex height of 5 μm or more and 700 μm or less is covered with a surface layer having a visible light transmission thickness of 1.5 mm or more and 8 mm or less. A molding method,
Forming a cavity for molding the surface layer on the surface side of the base material on which the concave and convex pattern is formed, using a mold;
Forming the surface layer by injecting a resin material into the cavity,
The base material contains a bright material and / or an inorganic pigment,
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;
Providing a protrusion with a height comparable to the thickness of the surface layer on the surface side of the substrate,
In the step of forming the cavity, the protrusion is brought into contact with the molding surface side for molding the surface of the surface layer of the mold, whereby the thickness of the surface layer is set between the surface of the substrate and the molding surface. A method for molding a resin molded product, characterized by ensuring comparable clearance. In claim 1,
A method for molding a resin molded product, wherein the protrusion is provided on a peripheral edge of the substrate. In claim 1 or claim 2,
The method for molding a resin molded product, wherein the uneven height of the uneven pattern of the substrate is 10 μm or more and 350 μm or less. In any one of Claim 1 thru | or 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 any one of Claims 1 thru | or 4 ,
The width of the upper Kige over preparative is not less 15mm or more, a thickness of the gate 1.0mm or more, the resin molding space between the gate and the substrate surface and wherein the at 0.5mm or more Molding method. In any one of Claims 1 thru | or 5 ,
A method for molding a resin molded product, wherein the substrate contains aluminum flakes as the glittering material.

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