JPH0156895B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a method for manufacturing urethane foam encapsulating molded products having different skin materials, and is mainly used in transportation engines such as automobiles, railway vehicles, aircraft, and ships,
The present invention also relates to a method suitable for manufacturing various interior products with excellent decorative appearance used for furniture and the like.

(Prior art) Recently, there has been a demand for interior-oriented designs that are luxurious and have a good texture for the appearance of interior materials such as safety pads (hereinafter abbreviated as instrument pads) of automobile instrument panels and other interior materials such as door trims. As a result, there is a demand for the decorative surface not only to be made of a single material, but also to use a composite skin material, for example, a combination of vinyl chloride skin material and fabric.

Conventionally used methods for creating 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. The joining methods used include joining the joint ends of the sheet and fabric by skin folding, or adhering the fabric lined with a vinyl chloride sheet to the surface of the vinyl chloride skin material with an adhesive, or welding. Ta.

However, the methods for manufacturing composite skin materials according to the above-mentioned conventional techniques 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. The problem with the method of flocking short fibers onto the surface of the skin material is that it lacks freedom in design. In addition, skin materials joined by the skin folding method are prone to leakage of injected liquid from the joint during urethane foaming, and it is difficult to apply the skin folding method to join three-dimensional parts. was subject to restrictions. 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 the 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 the peripheral edges of the fabric are welded using a welder does not require the use of solvents and the joining is completed in a short time, increasing productivity. It has many advantages such as high efficiency and low cost. However, in this method, it is necessary to strictly match the overlap between the upper weld bar and the planned welding portion of the fabric periphery, but the overlap often deviates, which impairs the appearance. Also in this case, there was a problem in that a level difference was created between the fabric and the vinyl chloride skin on the surface of the finished product, resulting in a lack of a sense of unity and an unfavorable appearance.

For the purpose of solving these problems, for example,
175650 describes a method for manufacturing automotive interior materials such as door trims that have surface layers made of different materials, but this method requires a lower mold that is divided into two parts, and a pattern that corresponds to the divided mold is described. However, a more complicated decorative pattern cannot be obtained, and there are serious drawbacks such as low productivity and high cost.

In addition, JP-A-59-101324 describes a method for manufacturing skin materials with partially different materials using the slush molding method, but this method requires molds and holding jigs depending on the pattern, and is still complicated. It is difficult to obtain decorative patterns, and productivity is also low.

Furthermore, JP-A No. 60-2320 describes a method of manufacturing a skin material having a multicolored surface by an in-die extension method using a masking material, but it is also difficult to obtain a complex decorative pattern with this method. Productivity is low.

(Problems to be Solved by the Invention) The purpose of the present invention is to provide a urethane material having a composite skin material that has excellent productivity using a welding method that completes joining in a short period of time, and that can also provide complex decorative patterns. An object of the present invention is to provide a method for manufacturing a foam-encapsulated molded product.

Another object of the present invention is to provide a method for manufacturing a urethane foam-encapsulated molded product having a composite skin material that has an excellent appearance without shifting the welding overlap between different skin materials.

Another object of the present invention is to provide a method for manufacturing a urethane foam-containing molded product that does not leak the foaming liquid onto the surface of the skin material when integrally foaming the urethane, and has a surface that is flat and has a sense of unity due to the urethane foaming. be.

(Means for Solving the Problems) The present invention provides a first skin material having substantially no air permeability on the lower electrode plate of a welder, and a thermoplastic material that is different from the first skin material and is preformed in the outer peripheral shape of the product. When the second skin material made of synthetic resin sheets is laminated in this order and the upper electrode plate is lowered and welded in a predetermined pattern, a concave groove is formed in the inner peripheral portion of the end surface of the upper weld bar that contacts the material to be welded. After pressure welding using a weld bar integrally provided with forming wedge-shaped small protrusions, the first skin is welded using the recessed groove corresponding to the wedge-shaped small protrusions formed on the inner peripheral edge of the surface of the welded part. A urethane foam encapsulation having different skin materials, characterized in that a composite skin material created by cutting and removing a second skin material portion covering the upper surface of the material is set in a foam mold and integrally foamed with a polyurethane foam raw material. Pertains to the manufacturing method of molded products.

Examples of the urethane foam-containing molded product of the present invention include various products such as automobiles, railway vehicles, aircraft, ships, instrument pads used for office use, headrests, sun visors,
door trim, armrest, seat cushion,
Examples include grab doors.

Hereinafter, the present invention will be explained with reference to the drawings.

FIGS. 1A and 1B are cross-sectional views illustrating a welding process using high-frequency welding as an embodiment of the present invention. FIG. 1A shows a state in which a first skin material 5 and a second skin material 6 are laminated on the lower electrode plate 1. In this case, since the size of the first skin 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.

The type of the first skin material is not particularly limited, but a substantially non-air permeable synthetic resin sheet such as polyvinyl chloride, polyvinylidene chloride, polyester, polyacrylonitrile, nylon, polyolefin, polyurethane, etc. is preferred. The surface of these sheets may be flocked with short thermoplastic synthetic resin fibers, or a decorative pattern may be applied by embossing or the like, if necessary. Furthermore, the sheet may have a different hue from the second surface material. Alternatively, it may be a composite sheet in which a fabric is laminated onto an air-impermeable sheet. Furthermore, it may be made of suede or suede-like material. The type of the second skin material is not particularly limited either, but for example, a substantially non-breathable synthetic resin sheet made of various synthetic resins such as polyvinyl chloride, polyvinylidene chloride, polyester, polyacrylonitrile, nylon, polyolefin, polyurethane, etc. is preferred. Also in this case, it may be made of suede or suede-like material.

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 peripheral portion of the tip surface 8 of the upper weld bar 3 that is in contact with the material to be welded. The welding method can be appropriately selected from heat pressing, high frequency welding, ultrasonic welding, etc. depending on the combination of the first skin material and the second skin material. When the first and second skin materials are made of the same material, high-frequency welding is preferable in the case of polyvinyl chloride, polyvinylidene chloride, etc., and ultrasonic welding is advantageous in the case of polyester, acrylic, polyolefin, etc. Furthermore, when the first and second skin materials are made of different materials, ultrasonic welding is generally preferred, and the conditions commonly used can be employed.

It is preferable that the wedge-shaped small protrusion 4 is made of a strong material such as steel in consideration of breakage resistance.
As illustrated in the figure, it is integrally joined to the inner wall surface of the weld bar using bolts or adhesive. The height h of the wedge-shaped protrusions is determined by the thickness d of the second skin material, and is generally within the range of 0.2d<h<0.7d. 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, a weld bar having a shape of h=0.5 mm, α=35°, and W=2 mm is used. In the normal high frequency welding method, generally 5 to 10 kg/
A pressurizing force of 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 second skin material is cut along the inner periphery of the surface of the welded part. Since it is necessary to insert the recessed groove 9, the selection of the pressing force is extremely important. In order to suppress sparks between the electrodes and achieve the above-mentioned purpose, the pressure may be selected appropriately, but for example, in the case of FIG. 1, the optimum pressure force was 3 kg/cm ² . In this case, a high frequency output of 7 kW, a frequency of 27.12 MHz, and a welding time of 4 seconds were suitable. As a result of leaving a narrow and thinnest second skin layer in the area pressed by the wedge-shaped small projections 4, the second skin material portion 7 covering the top surface of the first skin material is easily cut from there. become.

FIG. 2A is a sectional view of the welded part of the skin material after welding, and FIG. 2B is a cross-sectional view of the welded part of the skin material after welding, and FIG. The first skin material portion 1 is cut and removed along the line and protrudes outside the welding surface on the back side as necessary.
FIG. 2 is a cross-sectional view showing the state of the composite skin material welded portion after trimming has been completed by cutting out the portion 0 with scissors or the like.

Next, this composite 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 the two molds were engaged, a polyurethane foam raw material was injected into the foaming mold and foamed. When the mold is removed after the foaming reaction is completed, a molded product in which the core material, skin material, and polyurethane foam layer are integrally bonded can be obtained as shown in FIG. As shown in Figure 2B, the difference in level between the first and second skin materials after welding is
The height difference will be about 0.5 mm, but this level difference will be flattened by the foaming pressure during integral foaming of the urethane, so although some dents will remain on the welded surface, there will be no difference in level between the first and second skin materials, resulting in a flat surface. A molded product containing urethane foam with a good appearance and full of physical sensation can be obtained.

(Effects of the Invention) In the method of the present invention, process defects caused by misalignment of overlap margins, which have conventionally been a problem when welding different skin materials, are eliminated, productivity is improved, and the quality of the final molded product is improved. In terms of quality, although some dents remain on the welded surface, there are no differences in level between the different skins, and it is possible to finish the surface with a two-dimensional sense of unity. In addition, the problem of stains caused by seeping of adhesive or foaming liquid from the joint surface between different skin materials, which was seen in the sewing method, adhesive method, and skin folding method, cannot be solved; It is possible to stably manufacture products with decorative beauty while taking advantage of the many advantages of the welding method.

(Example) Examples will be described below.

Example 1 A 1.0 mm thick yellow colored polyvinyl chloride sheet with a decorative pattern on the surface was used as the first skin material.
A brown colored polyvinyl chloride sheet with a thickness of 1.0 mm was used as the second skin material and laminated as shown in Figure 1A, then h = 0.5 mm, α = 35°, W =
The upper weld bar, which is integrally provided with a wedge-shaped small protrusion with a shape of 2 mm, applies a pressing force of 3 Kg/cm ² and a frequency of
High frequency welding was performed under the conditions of 27.12MHz, output 7kW, and fusion time 4 seconds. Cutting and removing a portion of the second skin material covering the upper surface of the first skin material along the cutting recessed groove pressed by the wedge-shaped small protrusion;
Further, the first skin material protruding outside the welded surface on the back side was removed with scissors, leaving about 3 mm left, to obtain a composite skin material.

This composite skin material is set on the wall of the lower mold of the foaming mold, the core material is fixed to the wall of the upper mold, and after both molds are engaged, polyurethane foam raw material is injected into the foaming mold to perform foaming. After the reaction is completed, demold,
A molded product containing urethane foam was obtained.

[Brief explanation of drawings]

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 removing the second skin material covering the top surface of the first skin material and completing trimming, and Figure 3 shows the wedge-shaped small projections integrated. A cross-sectional view showing the shape of the upper weld bar provided, and FIG. 4 is a partial cross-sectional view of the final molded product. 1: Lower electrode plate, 2: Upper electrode plate, 3: Upper weld bar, 4: Wedge-shaped small projection,
5: first skin material, 6: second skin material, 7: second skin material portion covering the upper surface of the first skin material, 11: polyurethane foam, 12: core material.

Claims (1)

[Scope of Claims] 1. A first skin material having substantially no air permeability on the lower electrode plate of the welder, and a second skin material made of a thermoplastic synthetic resin sheet that is different from this and previously formed into the outer peripheral shape of the product. When the skin materials No. 2 are laminated in this order and the upper electrode plate is lowered and welded in a predetermined pattern, a small wedge-shaped protrusion for forming a concave groove is formed on the inner circumference of the end surface of the upper weld bar that contacts the material to be welded. After pressure welding using an integrally provided weld bar, the upper surface of the first skin material is covered using a recessed groove corresponding to a wedge-shaped small protrusion formed on the inner peripheral edge of the surface of the welded part. Second
A method for manufacturing a urethane foam-encapsulated molded product having different skin materials, characterized in that a composite skin material prepared by cutting and removing the skin material portion of the mold is set in a foaming mold, and the composite skin material is integrally foamed with a polyurethane foam raw material. 2. Manufacturing according to claim 1, in which the second skin material portion on the top surface of the first skin material is cut and removed, and the first skin material portion protruding outside the welded portion on the back surface is also cut off. Method.