JPH02194915A - Manufacture of foam mold with skin - Google Patents

Abstract

PURPOSE:To prevent the generation of creases and a defective shape, and to form a molded form having a slip having excellent appearance and quality by arranging a skin material shaped in a preliminary form which is the same as or approximating to an aimed shape into a cavity and pushing a preform against the mold surface of a main molding die by blowing pressure. CONSTITUTION:A skin material 3 is disposed onto the mold surface of the bottom force 20 of a preforming mold, and a top force 21 and the bottom force 20 are closed. The edge section of the skin material 3 is held between the top force 21 and the bottom force 20 at that time. An urethane foam resin is injected from the nozzle hole 22 of the top force 1 under the state. When a foamed resin is foamed, the skin material 3 is pushed against the mold surface of the bottom force 20 by blowing pressure, and the resin is cured under the state. A frame 15 is inserted into the baggy skin material obtained in this manner, and the skin material is disposed to the bottom force 50 of a main molding die 5. The bottom force 50 is mold-clamped with a top force 51. The urethane foam resin is injected into the baggy skin material from the nozzle hole under the state, and the urethane foam resin is foamed in the same manner as a preforming process. The skin material is pushed against the mold surface of the top force 51 by blowing pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing a foam molded article having a soft skin. The manufacturing method of the present invention can be used for manufacturing cushion parts such as automobile seats, headrests, armrests, etc.

[Prior Art] For example, automobile seats are made by covering a molded body made of a foamed resin such as foamed urethane with a skin made of leather, woven fabric, or the like. When manufacturing such a sheet, a method has generally been used in which a molded body and a skin are formed separately, and then the molded body is covered with a skin and integrated.

However, this method requires a large amount of man-hours, has the disadvantage that the position of the molded body shifts within the skin, resulting in poor appearance quality, and the skin moves away from the molded body, resulting in a poor feeling when sitting on it. .

Therefore, in recent years, a method has been developed to perform foam molding by placing a skin formed in a predetermined shape in a mold, and a method of integrally molding and integrally joining the molded body and the skin, method is becoming mainstream.

Incidentally, from the viewpoint of design or ergonomics, many sheets with uneven shapes are used. In order to form such an uneven shape on the skin in the above-mentioned integral molding, there is a method of forming the skin by using an extensible skin material and pressing and deforming the skin material against the mold surface with the pressure of foaming, or There is a method of using a skin material that has been shaped in advance into a predetermined uneven shape. The latter method of shaping the skin material into an uneven shape in advance includes sewing,
Methods such as vacuum forming or hot pressing are known.

[Problems to be Solved by the Invention] In a method of integrally molding a skin material by pressing it against a mold surface using the pressure of foaming and deforming it, a desired shape is formed by the elasticity of the skin material. The skin material used is not subjected to any process such as pre-shaping, and only the outer circumferential shape is cut into a predetermined shape. Therefore, it is necessary to use a skin material that is stretchable, and there is little freedom in selecting the skin material, and woven fabrics, leather, etc., which have low stretchability cannot be used. Furthermore, in cases where the uneven shape has a large step difference, the degree of elongation of the skin material at the convex valve and the opening portion differs greatly, which may cause problems in feel and appearance. In addition, in this method, the mold pushes the skin material when the mold is clamped, resulting in partial excess or deficiency in the skin material, which may cause problems such as wrinkles and poor shape after molding.

Furthermore, because the reproducibility of the expansion and contraction state of the skin material within the mold is poor, the reliability of dimensional accuracy is low, and even if the skin material is decorated with patterns, it is not possible to sufficiently ensure the aesthetic appearance. there were.

The method of shaping the skin material in advance into a predetermined uneven shape has the following problems. For example, when manufacturing a sheet as shown in FIG. 1, the entire sheet is divided into pieces along a curved surface as shown in FIG. Figure 10 (a)
(Part), there is a method of shaping the entire uneven shape. In this case, there are many parts to be sewn, resulting in a large number of man-hours. In addition, because the skin material shaped by sewing has a small holding force to maintain its shape, it cannot be said to be in a reliable positioning state when placed inside the mold, and the skin material and the mold surface are not in a reliable position. There is a risk that the product will be molded in a crooked state.

Further, when shaping is performed by vacuum forming, hot pressing, etc., the material of the skin material is limited to thermoplastic materials, and the degree of freedom in selection is low, and woven fabric, leather, etc. cannot be used. In order to ensure shape retention within the mold, it is necessary to increase the rigidity of the skin material, which may cause problems with the texture.

When molding a molded product with a bag-shaped skin such as a seat or a headrest, the bag-shaped skin material shaped into a predetermined shape is placed in a mold, and the skin material is foamed and molded. is convenient. However, since it is bag-shaped, the entire surface is placed inside the mold, and the position of the skin material cannot be adjusted from the outside. For this reason, skin materials that have been shaped by sewing have poor shape retention as described above.
), as shown in FIG. 8(b), when the mold is clamped, the upper mold 100
The skin material 101 is pressed by the mold surface, and as shown in FIG. 9(b), defects such as wrinkles 102 and poor shape 103 may occur.

The present invention aims to solve the various problems mentioned above.

[Means for Solving the Problems] The method of manufacturing a foam molded article having a skin according to the present invention includes placing a soft skin material in a preform mold, and forming a preform having the same shape as or approximating the target shape in an uneven shape. A preforming process in which a retaining layer made of foam is formed on the back side of the skin material to obtain a preformed body in which the preliminary shape of the skin material is retained; and a main molding step in which the preform is placed in the main mold so as to face the foamed resin, and the preform is pressed against the mold surface by the pressure of foaming of the foamed resin to obtain a foam molded product having a skin of the desired shape. shall be.

As the material for the skin material, conventionally used materials such as woven fabric, non-woven fabric, leather, resin, etc. can be used as they are. Although it does not need to be stretchable, it is desirable to have some degree of stretchability.

In the preforming step, the skin material is placed in a preform mold and shaped into a preform, forming a preformed body having a retaining layer made of foam on the back side of the skin material. This holding layer maintains the position of the preform within the main mold during the main molding process, thereby preventing misalignment. Further, even if positional displacement occurs, the retaining layer is a foam and the skin material is soft. Therefore, the preform is deformable, and by deforming the preform, the displacement is absorbed and a molded product having the desired shape can be formed. In addition, when the preliminary shape is close to the target shape, it is desirable to construct the preform so that it has the same developed shape as the developed shape of the target shape. In this way, even if the preform is deformed in the main molding process, no elongation force is applied to the skin material, so there is a high degree of freedom in the material of the skin material.

In order to configure the preform to have high shape retention, for example, there are methods such as increasing the thickness of the retaining layer at the edge portion of the preform or forming it into a rib shape.

To form a preform, the skin material may be formed into a preliminary shape by vacuum forming or the like, and then a retaining layer may be formed by molding or adhesion, or the skin material may be placed in a preform mold, Foam molding can be used to form the retaining layer and to shape the skin material.

In the main molding step, the preformed body is placed in the main mold,
This is the process of foam molding. Here, the preformed body is subjected to the pressure of foaming of the foamed resin. At this time, since the holding layer is a foam, it is easily deformed.

If the preliminary shape of the preform is close to the target shape, the preform is pressed against the mold surface of the main mold by the foaming pressure and deforms, and the skin material is also deformed to form the mold of the target shape. is formed. At this time, the shape of the preformed body is held by the presence of the holding layer, so that positional displacement is less likely to occur.

Furthermore, even if a positional shift occurs, the difference is small and can be absorbed by the difference between the preliminary shape and the target shape. Therefore, wrinkles and abnormal shapes are prevented from occurring in the skin of the molded article.

Note that if the difference between the preliminary shape and the target shape is large, the amount of deformation of the skin material will increase, so it is preferable to use a stretchable skin material.

The foamed resins used in the preforming step and the main molding step may be of the same type or different types. For example, if the hardness of the holding layer of the preform is higher than that of the foam formed in the main molding process,
It is also possible to form a molded body with partially different hardness.

[Operations and Effects of the Invention] In the method for manufacturing a molded article with a skin according to the present invention, in the preforming step, a preform having a skin material shaped into a preliminary shape that is the same as or similar to the target shape is formed. A molded body is formed. Then, in the main molding step, the preform is placed in the cavity, and the preform is pressed against the mold surface of the main mold by foaming pressure, thereby obtaining a molded product having the desired shape.

In other words, the invention! ! According to the manufacturing method, all or most of the uneven shape of the skin material is formed by preforming, so the number of sewing steps can be reduced or eliminated. The holding layer provides the preform with excellent shape retention within the main mold. Therefore, even if the preform is formed into a bag shape after preforming, there will be no indentation by the mold surface during mold clamping, preventing defects such as wrinkles and shape abnormalities, and producing molded products with high quality appearance with good reproducibility. can do. Furthermore, if the developed shape of the preliminary shape is configured to be the same as the developed shape of the target shape, the amount of elongation of the skin material in the main forming process can be made zero even if the preliminary shape and the target shape are different. can. This allows a greater degree of freedom in selecting the material of the skin material, and woven fabric, leather, etc. can also be used.

In general, the degree of freedom in the surface shape is greater than in the case of sewing, and various designs can be realized.

[Example] Hereinafter, the present invention will be specifically explained using examples. In this embodiment, the present invention is applied to the manufacture of a seat back for an automobile seat.

FIG. 1 is a perspective view of an automobile seat, and FIG. 2 is a partially cross-sectional perspective view of a seat back 1 of this seat. This seat back 1 includes a central portion 10 that supports the back of the human body;
It consists of side parts 11 that protrude forward on both left and right sides of a central part 10 and hold the human body from the left and right sides. The central portion 10 is provided with a plurality of grooves 12 extending in the vertical direction. The seat bag 1 also includes a woven fabric skin 13 and a urethane resin foam 1 that is covered with the skin 13 and integrally joined to the skin 13.
4 and an iron frame 15 embedded within the foam body 14.

The manufacturing method of this example will be described in detail below.

(Preforming process) As shown in FIG. 3, the skin material 3 is applied to the mold surface of the lower mold 20 of the preforming mold 2, and the upper mold 21 and the lower mold 20 are closed. At this time, the edge of the skin material 3 is held between the upper mold 21 and the lower mold 20. In this state, as shown in FIG.
Foamed urethane resin is injected from the nozzle hole 22. When a predetermined amount of resin is injected, the nozzle hole 22 is closed with a plug 23, and the foamed resin is foamed. Then, as shown in FIG. 5, the skin material 3 is pressed against the mold surface of the lower mold 20 by the pressure of foaming, and the resin solidifies in this state.

A partially sectional perspective view of the obtained preform is shown in FIG. This preformed body consists of a skin material 3 and a retaining layer 4 made of a foam integrally joined to the back side of the skin material 3. The approximate surface shape is maintained. That is, it consists of a preliminary central portion 30 and preliminary side portions 31 protruding on both left and right sides of the preliminary central portion 30, and a plurality of preliminary grooves 32 are formed in the preliminary central portion 30. Here, the auxiliary side portion 31 is gently continuous with the auxiliary central portion 30 and has a curved surface shape having a larger radius of curvature than the side portion 11 of the seat back 1. Further, the preliminary groove 32 has an arcuate cross section, and is wider than the groove 12 of the seat back 1, which has a substantially V-shaped cross section.

The skin material burrs 33 at the edges of this preformed body are cut and removed, and then the other skin material 6 separately formed by iHJ is sewn to match the inside surface, and the preform is turned over to form a bag-shaped skin body. Provided for the main molding process.

(Main molding process) There is a frame 15 inside the bag-shaped skin body obtained by L.
is inserted and placed in the lower mold 50 of the main mold 5 as shown in FIG. 7(a). Then, as shown in FIG. 8(a), the lower mold 50 is clamped with the upper mold 51. At this time, the upper mold 5
The protrusion 52 for forming the part 12 is located within the preliminary groove 32.

Here, since the width of the preliminary groove 32 is sufficiently wide, the protrusion 52 will be located within the preliminary groove 32 even if the position of the skin body shifts within the error range. The surface of the bag-like skin body is similar to the inverted shape of the mold surface of the main mold 5, and the shape retention property of the retaining layer 4 is high. This prevents problems such as the skin body being pressed by the mold surface and falling down, which occurred in the manufacturing method of .

In this state, a nozzle hole J (not shown) inside the bag-like skin body:
The foamed urethane resin is then injected, and the foamed urethane resin is foamed in the same way as in the preforming process. Then, as shown in FIG. 9(a), the skin body is pressed against the mold surface of the upper mold 51 by the pressure of foaming. At this time, the retaining layer 4 and the skin material 3 are deformed, the preliminary side portion 31 becomes the side portion 11, and the preliminary groove 32 becomes the groove 12. Note that the length of the surface of the preliminary groove 32 in the transverse direction is equal to the length of the protrusion 5.
The length of the surface in the transverse direction of 2 and the path distance. That is, since the unfolded shape is the same, the skin material 3 does not need to stretch. A molded article having a skin 13 with good appearance quality and without wrinkles or defective shapes as shown in FIG. 9(b) is formed.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a seat having a seat back formed according to an embodiment of the present invention, and FIG. 2 is a partially sectional perspective view of the seat back of FIG. Figures 3, 4 and 5 are cross-sectional views showing the preforming process of an embodiment of the present invention, and Figure 6 is a partial cross-sectional view of the preformed body obtained. FIG. FIGS. 7, 8, and 9 are explanations showing a state (a) in which the main molding process of an embodiment of the present invention is performed and a state (b) in which molding is performed in a conventional manufacturing method. FIG. FIG. 10 is a partially sectional perspective view of a seat back formed by a conventional manufacturing method. 2...Preliminary mold 3...Skin material 4...Retaining layer 5...Main mold 12...Groove
32...Preliminary groove Figure 3

Claims (1)

[Claims] (1) A soft skin material is placed in a preforming mold and shaped into a preliminary shape that is the same as or similar to the desired uneven shape, and a retaining layer made of foam is placed on the back side of the skin material. a preforming step to obtain a preformed body in which the preliminary shape of the skin material is maintained; and a preforming step in which the preformed body is placed in a main mold so that the skin material faces the mold surface, and the foamed resin is a main molding step of pressing the preform against the mold surface using the pressure of foaming to obtain a foam molded product having a skin of the desired shape; .