JPH0557885B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a method for manufacturing a safety pad for an automobile instrument panel, which has a thermoplastic synthetic resin skin material and a skin material such as decorative fabric or suede on at least a portion of the skin material. It is.

(Prior Art) Recently, there has been a demand for an interior-oriented design that is luxurious and has a good texture for the appearance of the safety pad (hereinafter abbreviated as "instrument pad") of an automobile instrument panel. It is desired not only to use a single material, but also to use a composite skin material, for example, a combination of a vinyl chloride skin material and a fabric. Traditionally, for automobile interior parts such as door trims, armrests, and seat cushions, composite skin materials combined with fabrics have been used, as seen in Japanese Patent Application Laid-Open No. 175650/1983, and this is set in a foam mold and integrally foamed with urethane. The technical concept of integrally bonding the core material, foam layer, and skin material is well known. However, conventionally used methods for making these composite skin materials include sewing thermoplastic synthetic resin sheets such as vinyl chloride sheets and fabrics, flocking short fibers onto the surface of the vinyl chloride skin material, or fabricating polyvinyl chloride sheets. Joining methods have been used, such as joining the joint end of the material and the fabric by skin folding method, or attaching the fabric lined with a vinyl chloride sheet to the surface of the vinyl chloride skin material with adhesive or weld welding. . However, no method has been found for manufacturing instrument pads using this type of composite skin material by integrally foaming urethane.

(Problems to be Solved by the Invention) The methods for manufacturing composite skin materials according to the prior art described above each have the following problems, and solutions to these problems have been sought. In other words, a skin material in which a thermoplastic synthetic resin sheet and another skin material are joined by sewing requires a lot of man-hours, the perforations are exposed, which is undesirable in appearance, and the foaming liquid leaks from the seams due to the foaming pressure. It was hot. In the method of planting short fibers on the surface of the skin material, there was a problem in that it limited the freedom of design. In addition, when the skin material is made by joining the joint end of the thermoplastic synthetic resin sheet and the fabric by the skin folding method, the injection liquid tends to leak from the joint during urethane foaming. It was difficult to apply and was subject to design limitations. Conventionally, the method of attaching fabric to the surface of a skin material using an adhesive is a labor-intensive process because it is a manual application process, and the adhesive tends to seep into the edges of the fabric, causing stains. However, even after the urethane was integrally foamed in the foaming mold, the fabric part was raised on the surface of the finished product, spoiling its decorative appearance. On the other hand, a method in which a fabric with a vinyl chloride sheet lined on the back side with an adhesive is placed on top of the vinyl chloride skin material and welded the peripheral edges of the fabric using a welder does not require the use of solvents, completes the bonding in a short time, and increases productivity. It has many advantages such as high cost and low cost. However, in this method, it is necessary to precisely match the overlap between the upper welder bar and the planned welding portion of the peripheral edge of the fabric, which often results in a misaligned overlap. Also in this case, there was a problem in that a level difference occurred between the fabric and the vinyl chloride skin on the surface of the finished product, which made it impossible to obtain a sense of unity and was unfavorable in terms of appearance. Techniques for welding fabric and thermoplastic synthetic resin are well known. In JP-A-59-94673, when joining two sheets, at least one of which is made of fabric, thermoplastic synthetic resin powder or terrax such as vinyl chloride or ABS is adhered and held at the joint, and a high frequency or ultrasonic welder is used. discloses a method of welding two sheets together. This case is characterized in that an adhesive layer is previously attached between the fabric and other sheet-like material. However, in the present invention, a skin material such as fabric or suede is sandwiched between two thermoplastic synthetic resin sheets, and these three are welded together, so the technical content is clearly different. The present application was filed with the aim of solving all of the problems of these prior art techniques.

(Means for Solving the Problems) The present invention provides a backing material made of a thermoplastic synthetic resin sheet on the lower electrode plate of a high frequency welder, a skin material such as fabric or suede, and a thermoplastic material preformed in the outer peripheral shape of the product. When the synthetic resin skin material is laminated in this order and the upper electrode plate is lowered and welded in a predetermined pattern, a wedge-shaped small protrusion is integrally provided on the inner circumference of the end surface of the upper weld bar that comes into contact with the material to be welded. After pressure welding using a weld bar, the thermoplastic synthetic resin portion covering the top surface of the fabric is cut and removed using the recessed groove formed on the inner peripheral edge of the surface of the welded part, and the back surface is removed as necessary. A composite skin material created by cutting out the skin material such as fabric or suede that protrudes outside the welded area and the backing material made of thermoplastic synthetic resin sheet is set in a foam mold and integrally foamed with polyurethane foam raw material. This is a method for manufacturing an instrument pad.

(Example) FIGS. 1A and 1B are cross-sectional views illustrating a weld welding process according to the present invention. FIG. 1A shows a state in which a backing material 5, a fabric 6, and a skin material sheet 7 are laminated on a lower electrode plate 1. In this case, the backing material does not necessarily need to be adhered to the back side of the fabric. Furthermore, since the size of the fabric and backing material can be set wider than the width between the weld bars, it is possible to avoid welding errors due to misalignment of the placement position. There are no particular restrictions on the type of fabric, but knitted fabrics with relatively high air permeability such as tricot, knitted, and knitted fabrics can be suitably used. This is because the thermoplastic synthetic resin melted by self-heating during welding easily permeates into the interior through the mesh, filling in the unevenness of the fabric structure, and furthermore, the upper and lower thermoplastic synthetic resins are compatible, creating strong bonding strength. This is because it will be done. Therefore, there are no particular restrictions on the fibers that make up the fabric, but nylon, polyester,
Preferably, a fabric made of synthetic fibers such as acrylic is used. Further, a skin material such as suede may be used instead of fabric.

As the thermoplastic synthetic resin used for the skin material sheet and the backing material sheet, vinyl chloride resin or vinylidene chloride resin, which has a large dielectric loss, is generally used. In particular, soft vinyl chloride resin is the most preferred material because it has a large dielectric loss even at room temperature.

In the embodiment shown in Figure 1A, vinyl chloride sheets with thicknesses of 1.0 mm and 0.45 mm are used for the skin material and backing material, respectively, and the fabric is made of polyester fiber tricots (70 pieces vertically and 70 pieces horizontally) with a thickness of 1.0 mm. 45
books) are used.

FIG. 1B is an explanatory view showing a state in which the upper electrode plate 2 is lowered and welded into a predetermined pattern. A feature is that a weld bar is used in which a small wedge-shaped protrusion 4 is integrally provided on the inner circumferential portion of the distal end surface 9 of the upper weld bar 3 that is in contact with the material to be welded. This wedge-shaped small protrusion 4 is preferably made of a strong material such as steel in consideration of breakage resistance, and is therefore integrally joined to the inner wall surface of the weld bar by bolting or using adhesive, as shown in FIG. 3. has been done. The height h of the wedge-shaped protrusion is determined by the thickness d of the vinyl chloride skin material, and is generally 0.2d<h.
A range of <0.7d is suitable. The thickness W of the weld bar 3 can be determined at any time with consideration given to the strength of the welded portion and design constraints. In the embodiment shown in Fig. 1, h=0.5mm, α=35°, W=2
A weld bar with a mm shape is used.
In the normal high frequency welding method, generally 5
A pressure of ~10 kg/cm ² is used, but in carrying out the present invention, the weld bar 3 is pressed and welded, and at the same time only the vinyl chloride skin material is applied along the inner periphery of the surface of the welded part. Concave groove 11 for cutting
The selection of the pressurizing force is extremely important. In order to suppress sparks between the electrodes and achieve the above objectives, the optimum pressing force was 3 kg/cm ² . In this case, the high frequency output is 7kw and the cycle time is 5 seconds. As a result of leaving the thinnest and thinnest vinyl chloride skin layer in the area pressed by the wedge-shaped small protrusions 4, the vinyl chloride skin material portion 8 covering the upper surface of the fabric is easily cut from there.

FIG. 2A is a cross-sectional view of the welded part of the skin material after welding, and FIG. 2B is a sectional view of the vinyl chloride skin material portion 8 covering the upper surface of the fabric 6 by cutting and removing it along the cutting groove 11. In addition, if necessary, the fabric portion 14 and vinyl chloride backing portion 15 protruding outside the welding surface on the back side are cut with scissors or the like, and forming is completed, and this is a sectional view showing the state of the welded part of the composite skin material. .

Next, this composite vinyl chloride skin material was set on the wall of the lower mold of the foaming mold, the core material was fixed to the wall of the upper mold, and after both molds were engaged, polyurethane foam raw material was injected into the foaming mold and foamed. . When the mold was removed after the foaming reaction was completed, a molded product in which the core material, skin material, and polyurethane foam layer were integrally bonded could be obtained. As shown in Figure 2B, the level difference between the fabric and the vinyl chloride skin material after welding is about 0.5 mm, but this level difference is flattened by the foaming pressure when the urethane is integrally foamed, so the welding surface is somewhat flattened. Although some dents remained, an instrument pad with a good appearance was obtained, with no difference in level between the fabric and the vinyl chloride skin material, and a sense of flat unity. FIG. 5 is a sectional view showing the state of the fabric welded portion of the instrument pad manufactured according to the present invention.

(Effects of the Invention) As described above, the present invention provides a backing material made of thermoplastic synthetic resin laminated on the lower electrode plate of a high-frequency welder, a skin material such as fabric or suede, and a pre-formed thermoplastic synthetic resin skin material. When performing weld welding on the pattern, by using a weld bar with wedge-shaped small protrusions integrally provided on the inner periphery of the tip of the upper weld bar, the thermoplastic synthetic resin skin material can be peeled off on the inner periphery of the weld surface. A concave groove corresponding to the wedge-shaped small protrusion is inserted, and along this concave groove, the thermoplastic synthetic resin skin material portion covering the top surface of the fabric or suede skin material is cut and removed, and preferably the outside of the welding surface on the back side is cut and removed. The composite skin material created by removing the protruding skin material such as fabric or suede and the backing material is set in a foam mold, and the polyurethane foam raw material is injected and foamed to form the above skin material, core material, and polyurethane foam. This is a method of manufacturing instrument pads by integrating urethane foam.

In this way, process failures due to misalignment of overlap margins, which have traditionally been a problem when welding skin materials such as fabric or suede and thermoplastic synthetic resin skin materials, are eliminated, improving productivity and improving the quality of the final molded product. Also, there is no difference in level between the skin material such as fabric or suede and the thermoplastic synthetic resin skin material, making it possible to finish the surface with a planar sense of unity. Also, the sewing method,
The problem of stains caused by seeping of adhesive or foaming liquid from the bonding surface between a skin material such as fabric and another skin material, which was seen in the adhesive method and the skin folding method, cannot be solved, and the problems described above cannot be solved. It becomes possible to stably manufacture products with decorative beauty while taking advantage of the many advantages of the weld welding method.

[Brief explanation of the drawing]

1A and 1B are cross-sectional views explaining the weld welding process according to the present invention, FIG. 2A is a sectional view showing the state of the skin material welded part after welding, and
Figure B is a cross-sectional view showing the state of the welded composite skin material after the vinyl chloride skin material covering the top surface of the fabric has been removed and trimming has been completed. FIG. 4 is a cross-sectional view showing the shape of the weld bar, FIG. 4 is a partial plan view showing the fabric welded portion on the surface of the composite skin material, and FIG. 5 is a cross-sectional view showing the welded portion of the final molded product. 1: Lower electrode plate, 2: Upper electrode plate, 3: Upper weld bar, 4: Wedge-shaped small projection,
5: Vinyl chloride backing material, 6: Polyester tricot skin, 7: Vinyl chloride skin material, 8: Vinyl chloride skin material portion covering the upper surface of the fabric,
12: Welding surface.

Claims (1)

[Claims] 1. On the lower electrode plate of the high-frequency welder, a backing material made of a thermoplastic synthetic resin sheet, a skin material such as fabric or suede, and a thermoplastic synthetic resin skin material preformed to the outer peripheral shape of the product are placed on the lower electrode plate of the high-frequency welder. A weld in which small wedge-shaped protrusions for forming recessed grooves are integrally provided on the inner circumferential portion of the end surface of the upper weld bar that contacts the material to be welded when the upper electrode plate is laminated in order and the upper electrode plate is lowered and welded in a predetermined pattern. After pressure welding using a bar, thermoplastic synthetic resin is used to cover the upper surface of a skin material such as fabric or suede by using the recessed grooves corresponding to the wedge-shaped small protrusions formed on the inner periphery of the welded surface. A method for manufacturing a safety pad for an instrument panel, characterized in that a composite skin material prepared by cutting and removing a portion is set in a foam mold and integrally foamed with a polyurethane foam raw material. 2. Cut and remove the thermoplastic synthetic resin portion covering the upper surface of the fabric or suede surface material, and remove the backing made of the fabric or suede surface material and thermoplastic synthetic resin sheet that protrudes outside the welded area on the back surface. The manufacturing method according to claim 1, wherein the material portion is cut out.