JP3286825B2 - Synthetic leather in-mold molding - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plastic molded article having a high quality texture and a high quality of clothing, which has synthetic leather adhered to the surface at the same time as molding.

[0002]

2. Description of the Related Art In recent years, the decoration of the surface of a plastic molded product has been required to have a high-quality feeling including the texture.
In general, as a method for decorating the surface of a plastic molded product, as a method performed on a molded plastic product, direct printing, transfer printing, foil stamping, painting, electrostatic flocking, underwater transfer method, and the like are used. As a method of decorating simultaneously with plastic molding, a simultaneous molding and painting method by an in-mold molding method is generally used. A method of decorating a plastic molded product by adding some design by printing is a variety of options up to a decoration surface having a flat surface and a secondary curved surface. The printing method is limited to the in-mold molding method in the tampo printing, the underwater transfer method, and the simultaneous painting method. In the in-mold molding method, a printed decorative sheet is inserted into a molding die before injection molding or blow molding is performed, and only the pattern of the decorative sheet is transferred to a molded product, or the decorative sheet is decorated. The sheet itself is integrally formed to decorate a predetermined first to third curved surface of a molded product, and various kinds of decorative sheets are used. Japanese Patent Application No. 5-159947 proposes a method and a molded article in which synthetic leather is used as a decorative sheet and is subjected to in-mold molding in an injection mold.

[0003]

In order to decorate the tertiary curved surface of the molded article by the in-mold molding method, it is premised that the decorative sheet has elongation suitability so as to be in close contact with the tertiary curved surface.
If there is no elongation suitability, the decorative surface literally wrinkles, impairs the appearance and becomes dirty. Synthetic leather is not a stretchable decorative sheet. Therefore, for in-mold molding of a plastic molded product having a tertiary curved surface using this material, Japanese Patent Application No. Hei.
In the case of -159947, the periphery of the synthetic leather sheet is firmly clamped with a female mold and a male mold of injection molding, then injection molding is performed, and the synthetic leather is forcibly stretched by mold clamping, resin pressure and heat to integrally mold. In this case, a method has been proposed to prevent the cut of the synthetic leather film around the cavity, which is likely to occur in this case, by attaching a flange around the molded product. The molded product has a certain level of curvature and thickness. Is effective for However, when the curvature becomes large, the synthetic leather sheet is forcibly stretched in the mold, so that the stress that the synthetic leather sheet tends to return to remains in the decorative molding,
After molding, there is a problem in that the molded product is deformed (warped) and a target final shape cannot be obtained. This is a phenomenon that appears particularly when the thickness of the molded product is small. Further, when the curvature of the molded article becomes large, the forcing force exceeds the limit, and there is a problem that the above-mentioned film breakage occurs and molding becomes impossible. Further, depending on the high temperature and high pressure of the molten resin, there is a problem that the skin portion of the synthetic leather is degraded or irregularities occur, resulting in poor appearance. Synthetic leather sheets generally have a three-layer structure of skin / adhesive layer / base cloth, and the skin is made of vinyl chloride or polyurethane resin. It was not possible to avoid the above-mentioned troubles such as deterioration and unevenness. The present invention has been made in view of the aforementioned problems, and uses synthetic leather,
An object of the present invention is to provide a decorative molded article having a tertiary curved surface having a large curvature without wrinkles, cutouts, and deterioration.

[0004]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a synthetic leather sheet which is inserted between a male mold and a female mold of an injection mold and clamped. Injecting the molten resin, in the in-mold molding of synthetic leather to obtain a decorative molded product with synthetic leather attached to the surface,
At the time of mold clamping, the central portion of the synthetic leather sheet is sandwiched and fixed between the male stripper plate and the female parting surface facing the stripper plate, and the periphery of the synthetic leather sheet is not fixed, The flange of a molded article with a peripheral flange formed by injecting a molten resin from a male mold side and being molded by a mold provided with a dug portion deeper than the synthetic leather sheet thickness around the molding cavity of the female mold The synthetic leather base fabric is a non-woven fabric, and has a foamed layer formed by a wet method.

[0005]

According to the present invention, the synthetic leather sheet sandwiched between the male mold and the female mold is firmly fixed at the central part, but can move without being clamped at the peripheral part. The peripheral part of the leather sheet can be moved so as to be drawn toward the center, so that tension is not applied, so that the film does not break, and there is no residual stress due to excessive tension on the molded product, so there is no deformation after molding, and it is also synthesized. Due to the heat insulating effect of the foam layer of the leather base fabric, deterioration of the skin, unevenness and the like are eliminated, and at the same time a soft touch is given.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. FIG. 1 is a cross-sectional view of an in-mold molding die 30 according to the present invention, in which left and right (up and down in the drawing) are symmetrical. FIG. 1 shows a state in which the synthetic leather sheet 1 is preliminarily fixed so as to cover the cavity 4 of the female mold 2. The mold 30 includes a female mold 2 and a male mold 3, and the cavity 4 of the female mold 2 has four impositions as shown in the plan view of the female mold 2 in FIG. The female mold 2 is provided with a ventilation hole 13 communicating with a vacuum exhaust source, and the ventilation hole 13 is opened as a vacuum hole 13 in the parting surface 12 of the female mold 2. The synthetic leather sheet 1 is sucked into a predetermined position on the parting surface 12 by a vacuum hole 13 and preliminarily fixed as shown in FIG. The position of the vacuum hole 13 is the parting surface 12 around the female mold.
In this case, the position, the number, the shape, and the degree of vacuum may be appropriately selected so that the synthetic leather sheet 1 does not fall under its own weight.

In FIG. 1, a stripper plate 8 is disposed on the male mold 3 so as to be movable in the left-right direction in FIG. The stripper plate 8 is configured to be pressed in the direction of the female mold 2 by the repulsive force of the spring 10. Although the stripper plate 8 is originally intended to release the molded product from the mold, the present invention also has a function of fixing the synthetic leather sheet 1 at the mold central portion 11. The fixing position is indicated by 11 in FIG. 4A, but may be a part of the center instead of the upper and lower lines. The stripper plate 8 forms a part of the male molding surface when the mold is clamped. Here, the position of the stripper plate 8 when the mold 30 is opened is closer to the female mold 2 than to the portion of the core surface 6 of the male mold 3 closest to the female mold 2 as shown in FIG.
A gate 7 for injecting the molten resin is provided at the center of the core surface 6.

Next, as shown in FIG. 1, when mold clamping is started with the synthetic leather sheet 1 preliminarily fixed, the stripper plate 8 at the center contacts the synthetic leather sheet 1 first, and the stripper plate 8 at the center of the female mold. The synthetic leather sheet 1 is sandwiched and fixed together with the protruding parting surface 11. On the other hand, the periphery of the synthetic leather sheet 1 is not fixed but is left free. This state is shown in FIG.
4A is maintained in a free state in which it can move in the direction of the arrow as shown in FIG. On the other hand, FIG. 4B shows a state at the time of the conventional mold clamping, in which the synthetic leather sheet is firmly fixed around the individual cavities. Giving the freedom of movement around the synthetic leather sheet 1 is one of the important points of the present invention, and this state is clearly shown in FIGS. 2 and 3, one side of the mold 20 is omitted. 2 and 3 show a dug portion 16 around the cavity and an end portion 17 of the synthetic leather sheet 1 therein.
The behavior of is shown. FIG. 2B is an enlarged view of the dug portion 16. As shown in FIG. 2, when the core surface 6 approaches the cavity surface 5, the left and right ends 17 of the synthetic leather sheet 1 are moved.
Is drawn toward the parting part 11 of the center, and at the end of the mold clamping, the left and right ends 1 of the synthetic leather sheet 1 are
A space 15 is formed outside of. At this time, the peripheral stripper plate 8 forms a dug portion 16 having a predetermined depth larger than the thickness of the synthetic leather sheet 1 together with the opposing parting surface 12. FIG. 3 shows a state in which injection molding is performed in this state. The melted resin 24 is injected from the gate 7 to further press the synthetic leather sheet 1 against the cavity molding surface, and flows into the dug portion 16. In this state, the space 15 is further expanded. That is,
The end 17 of the synthetic leather sheet 1 is moving toward the center. As described above, in the steps of mold clamping and injection molding, the periphery of the synthetic leather sheet 1 is firmly clamped as in the related art, and the synthetic leather sheet 1 is not forcibly stretched. The object does not have any stress that tends to return to its original shape, and deformation due to warping is unlikely to occur even in a thin molded product.

FIG. 5 (a) shows a further enlarged view of the molded state at the edge of the synthetic leather sheet 1. FIG.
(B). In contrast to this, the state of the edge portion in the conventional molding method is added to FIGS. 6A and 6B, and a conventional improved type provided with a flange portion (flange portion) 19 is shown in FIG.
It is shown in (b). The edges 18 of the cavities shown in FIGS. 5 to 7 show the same action as a blade in the conventional molding method. When the tensile strength of the synthetic leather sheet 1 by stretching is increased, the synthetic leather sheet is broken at the edge 18, and particularly, The epidermis had a high degree of destruction, which was against the purpose of decoration. However, this edge 18 does not cause any trouble in the present invention. FIG. 8A is a perspective view of an integrally molded article 40 having a three-dimensional curved surface obtained by the above-described molding, and FIG. The state of the peripheral end of the molded product 40 trimmed at the position indicated by the arrow 23 is shown. As shown in FIG.
6, the flange 1 formed around the molding 40
9 is trimmed after molding, and the molded product has a predetermined finished size. The space 15 does not need to be completely filled with the resin 24 as shown in FIG. 3, and may be a short mold.

As shown in FIG. 9, the synthetic leather sheet 1 generally comprises a surface 20, an adhesive layer 21, and a base cloth 22 from the surface. As the skin, there are a vinyl chloride type and a polyeletan type, and polyurethane having a high heat resistance of 180 to 200 ° C. is preferably used. As the base fabric 22, a woven fabric made of fibers such as rayon, polyester, cotton, and nylon, and a nonwoven fabric on one side are used, but a stretchable polyester-based nonwoven fabric is preferably used. Further, a heat-insulating and soft-feeling base fabric 22 manufactured by the wet method described below is employed, and a printed two-component urethane-based adhesive layer 21 is printed on the base fabric 22. The skin 20 was dry-laminated. With the wet method, the base fabric is raised, impregnated with a solution of polyurethane dissolved in a solvent such as dimethylformamide, methyl ethyl ketone, and coagulated with water.
By a method in which the solvent and water are replaced with warm water, water that has been present in the polyurethane (water that has been replaced with the solvent) during drying is removed, and that portion becomes hollow, and a base fabric of a polyurethane layer having bubbles is obtained. On the other hand, in the dry method, the skin is directly adhered to the base cloth, and the texture is completely different.

(Examples) The present invention will be further described with reference to specific examples. In this example, an eyeglass case was selected as a specific molded product, and processed under the following conditions. 1) Synthetic leather sheet A polyurethane-based skin with a wet thickness of 20 μm,
Base fabric 0.8m made of polyester non-woven fabric wet-processed
m, a sheet having a total thickness of 0.82 mm was obtained as a sheet 380 mm in the flow direction and 200 mm in the width direction. On the other hand, as a comparative example, a total thickness of 0.7 mm and a sheet size of 380 mm × 20 in which a polyurethane-based skin was similarly laminated on a cotton / rayon blended base fabric by a dry method.
A 0 mm synthetic leather sheet was used. 2) Molding condition Injection molding machine Mold clamping force: 120t Mold size: 500 × 400mm Molding number: 4 pieces Cavity size: Long diameter 162mm, short diameter 72mm, depth 17mm Molding resin: High impact polystyrene (HIPS) resin Temperature: 200 ° C. Cycle time: 30 seconds Synthetic leather sheet setting method: 1) Fixing the central part according to the present invention 2) Fixing the entire circumference (comparative example) The result of integral molding under the above conditions was as follows. . 1) Mold structure Warpage (deformation) A Fixed at center only ○ B Fixed all around (comparative example) × 2) Synthetic leather specification Warp (deformation) Transformation of skin A Wet nonwoven fabric ○ ○ B Dry process (cotton, rayon blended) ) × ×

[0012]

According to the present invention, when a molded article having a tertiary curved surface is formed by integral molding using a synthetic leather sheet as a decorative sheet, the skin of the synthetic leather does not deteriorate due to heat and the appearance is favorable. In addition, the deformation after molding due to residual stress of the synthetic leather layer is eliminated, and an integrated molded product with stable finished dimensions is obtained. By using this, a plastic molded product having high texture and high quality can be stably obtained. In addition, the production loss rate during in-mold molding has been improved, which has helped to streamline production.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a mold when a synthetic leather sheet is inserted.

FIG. 2A is a cross-sectional view of the mold when mold clamping is completed. FIG.

FIG. 3 is a cross-sectional view of a mold after injection molding.

FIG. 4 is an explanatory view of a molding imposition and a method of fixing a synthetic leather sheet.

FIG. 5 is an explanatory diagram of a molding situation around a synthetic leather sheet.

FIG. 6 is an explanatory diagram of a molding situation around a conventional synthetic leather sheet.

FIG. 7 is an explanatory diagram of a forming state of an improved peripheral portion of a conventional synthetic leather sheet.

FIG. 8 is a perspective view and a sectional view of a molded product.

FIG. 9 is a diagram showing a laminated structure of a synthetic leather sheet.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Synthetic leather sheet 2 Female type 3 Male type 4 Cavity 5 Cavity forming surface 6 Core surface 7 Gate 8 Stripper plate 9 Stripper bolt 10 Spring 11 Projecting parting surface 12 Parting surface 13 Suction hole 14 Vacuum hole 15 Space 16 Engraved portion 17 Synthetic leather sheet end 18 Cavity edge 19 Flange (flange) 20 Skin layer 21 Adhesive layer 22 Base cloth layer 23 Trimming position 24 Resin 30 Mold 40 Molded product

Claims (3)

(57) [Claims] 1. A decoration in which a synthetic leather sheet is inserted between a male mold and a female mold of an injection mold, the mold is clamped, molten resin is injected from the male mold side, and synthetic leather is stuck on the surface. In the in-mold molding of the synthetic leather to obtain a molded product, at the time of clamping, the central portion of the synthetic leather sheet is fixed by being sandwiched between the male type stripper plate and the female parting surface facing the stripper plate, An in-mold molded article of synthetic leather, wherein the synthetic leather sheet is formed by injecting a molten resin from a male side without fixing the periphery of the synthetic leather sheet. 2. The method according to claim 1, wherein said flange is formed by trimming said flange of a molded product with a peripheral flange formed by a mold having a dug portion deeper than said synthetic leather sheet thickness around said female mold cavity. An in-mold molded article of the synthetic leather according to claim 1, characterized in that: 3. The synthetic leather base fabric is a non-woven fabric,
The in-mold molded article of synthetic leather according to claim 1, further comprising a foamed layer formed by a wet method.