JPS6213788Y2 - - Google Patents

Description

[Detailed explanation of the idea]

The object of the present invention is to provide a foamed composite material for molding, which can be deep drawn and is particularly suitable for automobile interior and exterior materials such as crash pads (instrument panels). . Traditionally, automobile interior and exterior materials such as crash pads (instrument panels) have been molded in advance by a slush molding method, or by vacuum forming from ABS, vinyl chloride sheets, etc. The urethane foam stock solution is injected into a predetermined mold by placing the outer cover in a predetermined mold, or the urethane foam stock solution is filled into a cavity of pre-shaped core material and skin material and foam molding is performed. The so-called two-stage molding method was often used,
In such conventional methods, the process is complicated, the work efficiency is poor, the loss rate is high, and it is not only uneconomical, but also it is difficult to mold products with complicated shapes. For this reason, the applicant first placed a skin material made of a polyvinyl chloride sheet lined with a urethane foam sheet on a pre-shaped core material, adhered it through a hot melt adhesive film, and simultaneously applied heat pressure in one motion. A method of molding was proposed (see Japanese Patent Publication No. 1212/1983). However, in the first place, forming methods using heat and pressure such as vacuum forming are methods in which a heated and softened sheet is brought into close contact with a mold using a difference in air pressure or pressing force. Since it is difficult for the heated and softened sheet to be stretched uniformly over the entire uneven mold surface, the wall thickness tends to differ between the bottom and side surfaces of the molded product. When deep drawing is performed, the pores in the foam layer are destroyed and deformed due to three-dimensional thermal and pressure stress in the vertical, horizontal, and thickness directions that inevitably occur during forming, causing the gas inside the cells to leak to the outside. This has the disadvantage that the sheet surface becomes avatar-like because the pores collapse. On the other hand, the prior art proposed earlier by the present applicant is a one-action molding method compared to the conventional two-step molding method, so it has a remarkable effect in terms of the molding method, but on the other hand, it However, since it has a simple structure in which a general-purpose urethane foam sheet is attached to a vinyl chloride sheet, it cannot deal with the inevitable three-dimensional thermal and pressure stress that occurs during molding, and in particular, Improvement of the physical properties of the material is not necessarily sufficient for deep drawing of W (H: depth of molded product, W: diameter or short side length of molded product) 0.4 (elongation rate 260%) or more. is desired. As a result of intensive research to improve the above-mentioned drawbacks, the present inventor was able to obtain a moldable foam composite suitable for deep drawing by adopting the structure described in the claims of the utility model registration. . According to the research conducted by the present inventors, foamed composites suitable for deep drawing have the following characteristics: (1) little decline in elongation, that is, resistance to fluctuations in forming conditions, and (2) a high closed cell ratio, that is, forming It was confirmed that less sagging is an important requirement, and as a result, the present invention was achieved. The drawings show one embodiment of the present invention, and the present invention will now be explained with reference to the illustrated example. In the foamed composite 1 for molding of the present invention, the foam layer 2 has coarse closed cells 3 densely formed on one side in the thickness direction, and fine closed cells 4 densely formed on the other side, The pores are formed such that the pore diameter becomes smaller sequentially from the coarse closed cells 3 to the fine closed cells 4,
As a result, the foamed layer 2 has a gradient from coarse to dense in the thickness direction. Further, on the surface of the foam layer 2 on which the coarse closed cells 3 are formed, a non-porous surface coating (hereinafter simply referred to as surface coating) having a decorative property is applied with a desired drawing pattern, various colors, etc., as appropriate through the skin layer 5. On the other hand, a non-breathable backing film (hereinafter simply referred to as backing film) 8 is bonded to the surface of the foam layer 2 having micro closed cells 4 via a skin layer 7. It has a three-layer structure that is laminated and bonded together. In the illustrated example, the facing film 6 and the backing film 8 are laminated and bonded via the skin layers 5 and 7, but the skin layers 5,
7 is not necessarily required and can be omitted as appropriate. The foamed composite for molding of the present invention has the structure as described above, and the thermoplastic resin used is preferably vinyl chloride for the foam layer 2, the surface coating 6, and the backing coating 8, and in addition, polyurethane, polyolefin, etc. The foamed layer 2,
It is desirable that the surface coating 6 and the backing coating 8 be of the same quality as much as possible. It goes without saying that various types of vinyl chloride can be used, such as general-purpose homopolymers, copolymers, straight resins, paste resins, etc., but especially for deep drawing molding, the plasticizer blending ratio is higher than that of straight resins. In view of the decrease in 100% modulus due to the 100% modulus, it is desirable to use an ethylene-vinyl chloride copolymer resin with a relatively good elongation and a high degree of polymerization. The vinyl chloride resin may contain general-purpose plasticizers, foaming agents, stabilizers, lubricants, various fillers such as pigments, and other flame retardants as necessary, depending on the classification of the foam layer 2, facing film 6, and backing film 8. This does not preclude the addition of UV inhibitors, antistatic agents, crosslinking agents, etc. To exemplify the method of manufacturing the foamed composite for molding of the present invention, first, the foam layer 2 is made by semi-gelling a calender sheet containing a foaming agent, and then placing it in a known foaming furnace equipped with an endless belt made of metal such as stainless steel. Introduce, 3~
By performing foaming with four stages of heat management, dense micro closed cells 4 are formed on the lower surface in contact with the endless belt, and closed cells with pore diameters sequentially increase in the thickness direction of the open upper surface. is formed, so that coarse closed cells 3 are formed in the uppermost layer, and a foam is obtained in which skin layers 7 and 5 are formed on the surface in contact with the endless belt and on the uppermost surface, respectively. In this case, the skin layers 5 and 7 are related not only to the heat management conditions in the foaming furnace but also to the number of added parts of the blowing agent and the expansion ratio, but the blowing agent has a ratio of 4.5 to 4.5 to 1.5 to It is desirable to add 5 parts by weight or more and to suppress the expansion ratio to 5 times or less. A facing film 6 and a backing film 8 are laminated and bonded to the foam produced as described above in accordance with a conventional method to obtain a foamed composite for molding. In order to bond the foamed composite material for molding onto the core material of an interior material such as a crush pad (instrument panel) that has been shaped in advance, various methods such as vacuum forming, pressure forming, drawing, etc. can be used. Specifically, it can be manufactured by various methods such as straight molding method, drape molding method, plug assist molding method, blow assist molding method, and slip molding method. It is most advantageous to use a molding method and to mold according to the applicant's prior art one-behavior molding method. That is, according to the one-action molding method, the foam composite for molding of the present invention can be placed on a pre-shaped core material, laminated and bonded in one action, and simultaneously molded into a predetermined mold. Moreover, the decorative pattern on the surface coating film 6 can be formed without any loss at that time. Therefore, in order to impart cushioning properties to the cavities of the core material and skin material, which are individually shaped as in the past, a urethane foam stock solution is filled and foam-molded.
It has the advantage of not requiring a complicated two- or three-stage process. In addition, the present invention has a three-layer structure in which the foam layer 2 is formed of coarse closed cells 3 and fine closed cells 4, and both sides of the foam layer 2 are integrally covered with a non-porous surface film 6 and a backing film 8, respectively. It is formed into a three-dimensional dense structure in the vertical, horizontal, and thickness directions, and is strong against the three-dimensional thermopressure stress that inevitably occurs during forming (particularly during deep drawing), so it is difficult to foam. Even if the bubbles in layer 2 are subjected to significant deformation, the pores will not collapse and the air within the bubbles will not overflow. Therefore, the volume of the bubbles in foam layer 2 will always maintain three-dimensional equilibrium, and the bubbles will not collapse. Avatar due to depression of surface coating 6 etc. caused by
Moreover, there are no adverse effects such as uneven thickness. Further, in the present invention, since the foam layer 2 is formed to have a density gradient in the thickness direction, the foam composite for molding has the advantage that it can maintain a feel and texture that closely resembles natural leather. As mentioned above, in the present invention, the foam layer 2 has a three-dimensional air-tight structure in which the foam layer 2 is integrally covered with the non-porous surface film 6 and the back film 8, so that the reduction ratio H/
Suitable for deep drawing of W0.4 or higher, drawing ratio H/
Of course, it can also be applied to those where W is less than 0.4.
In the case of molding with a reduction ratio H/W of less than 0.4, the foamed layer 2 may be formed of closed cells with uniform pore size without forming a density gradient. Furthermore, when the skin layer 7 is formed on the side of the dense closed micro cells 4 of the foam layer 2, a composite structure of the layer formed by the dense closed micro cells 4 and the skin layer 7 is formed. Therefore, it is possible to withstand three-dimensional thermal pressure stress, and in such a case, the backing film 8 can be omitted as appropriate if necessary. The following table compares the physical properties when molded with a reduction ratio of H/W of 0.4 with conventional foamed composites.

[Table] In other words, compared to the conventional foam composite, the present invention has
It is recognized that tearing, cracking, settling, and the formation of avatars are greatly improved, and good physical properties can be imparted almost independently of the temperature during molding. As described above, in the present invention, the foam layer is formed from coarse closed cells to fine closed cells in the thickness direction, with the pore diameter gradually decreasing, and as a result, the foam layer has a gradient from coarse to dense in the thickness direction, and It has a three-layer structure in which a non-breathable surface film is laminated on the side of the coarse closed cell side, and a non-breathable backing film is laminated on the side of the fine closed cell side to cover the foam layer, making it foamable. The body is formed into a three-dimensional air-tight structure in the vertical, horizontal, and thickness directions, which completely eliminates the possibility of air leakage due to the destruction of air bubbles during molding, especially during deep drawing. There is no surface avatar or unevenness in thickness, and it can be made to have a texture and feel that closely resembles natural leather. Therefore, it can be used for molding items such as cushion pads, etc., and can also be used for furniture, interior decoration, etc. It is possible to make a foamed composite material for molding that is compatible with high-grade directionality of various facing materials and the like.

[Brief explanation of the drawing]

The drawing is a sectional view of an embodiment of the present invention. 1... Foamed composite for molding, 2... Foamed layer, 3...
...Coarse closed cells, 4...Fine closed cells, 5,7...
...Skin layer, 6...Non-breathable top coating, 8...Non-breathable back coating.

Claims (1)

[Scope of utility model registration request] In a foamed composite for molding made of a soft thermoplastic resin such as vinyl chloride, the foam layer has a gradient of density from coarse closed cells to fine closed cells in the thickness direction, and the coarse closed cells of the foam layer are An integrated three-layer structure in which a non-breathable surface film with decorative properties is laminated and coated on the surface where the micro-closed cells are formed, and a non-breathable backing film is laminated and coated on the surface where the micro closed cells are formed. 1. A foamed composite for molding, characterized in that the foamed layer has a three-dimensional dense structure in which the cells are formed in the foamed layer.