JPH0732527A - Production of side collision shock absorber for vehicle - Google Patents

Abstract

PURPOSE:To prevent the falling-off of a powder from hard polyurethane foam by cutting a shock absorber composed of hard polyurethane foam from free foam to mold the same and covering the moded shock absorber with a synthetic resin film. CONSTITUTION:For example, in a door trim, the shock absorbing material is provided to the interior of a car by bonding a skin reinforcing material 2 having shape retentivity to the inside of a skin 1 and attaching a shock absorber 3 composed of hard polyurethane foam and covered with a synthetic resin film to the skin reinforcing material 2. As a rubbing sound measure, the shock absorber 3 covered with the synthetic resin film and the door outer panel 4 of a car are bonded by an adhesive A. The shock absorber 3 is cut from the hard polyurethane foam obtained by a mold opened at one end thereof or continuous foaming equipment restricted on the lateral part thereof so that the vertical direction of foaming becomes a shock absorbing direction and molded so as to have a vertically long cell structure.

Description

Detailed Description of the Invention

[0001]

[Industrial application] Interior parts of automobiles, door trims,
The present invention relates to a shock absorber such as a foot protector (leg protector) and a knee pad (knee protector).

[0002]

2. Description of the Related Art Conventionally, interior parts of automobiles have been manufactured by directly attaching the shock absorbing material to a door base material (wood or polypropyne resin) by adhering the shock absorbing material to an appropriate portion of a vacuum formed skin with an adhesive or the like. It was installed. Separately, it was manufactured by directly injecting a polyurethane foaming undiluted solution having excellent impact absorption performance into a vacuum-molded skin.

[0003]

Even when a foam-like impact absorbing material is separately formed or cut out and is made by an adhesive method at a required place, the powdery substance is scattered in the air to deteriorate the environment.
Moreover, it raises the cost and lowers the work efficiency. Further, the method of directly injecting a polyurethane foaming undiluted solution having a good shock absorbing performance into a vacuum-molded skin has a problem that the shock absorbing foam becomes a brittle powder with the lapse of time and the appearance has a reduced commercial value. Further, a rubbing noise is generated between the shock absorber and the iron plate portion, and countermeasures against it have been required.

[0004]

[Means for Solving the Problems] The present invention has been achieved as a result of intensive research to solve the above problems. That is, in a collision / shock absorbing member from the side, front and rear attached to an automobile interior, a shock absorbing body made of hard polyurethane foam is cut out from free foam and molded, and the surface of the shock absorbing body is wrapped with a synthetic resin film. This is to prevent the powder falling off of the rigid polyurethane foam, and a rubbing sound is generated at the portion in contact with the shock absorber made of the rigid polyurethane foam and the iron plate portion,
As a method for preventing this, a method of adhering an iron plate portion (outer plate portion) that is in contact with the impact absorber, which is formed by cutting and molding a free foamed body of rigid polyurethane foam and covering the surface of the impact absorber with a synthetic resin film, is rubbed. It was found to be effective in preventing noise. In addition, for fragile powdering of the rigid polyurethane foam due to aging, it may be effective to cut out and mold so that the longitudinal direction of the foamed cell of the rigid polyurethane foam with the elongated foamed cell structure matches the impact absorption direction. Obviously, the present invention has been reached.

The present invention will be described with reference to the drawings. FIG. 1 shows a conventional example of a door trim. The shape-retaining skin reinforcing material 2 was brought into contact with the inside of the skin 1, and the foamed impact absorbing material 3 made of a hard polyurethane foam was cut out from a free foamed body or molded by stirring with a stirrer.

FIG. 2 is a cross-sectional view of a door trim according to the present invention, in which a shock absorbing body 3 cut and molded from a free foam of rigid polyurethane foam is wrapped (wrapped) with a synthetic resin film and the powder of the rigid polyurethane foam is dropped. Is to prevent. Further, as a countermeasure against rubbing noise, the shock absorber, which is wrapped with a synthetic resin film, and the automobile door outer plate 4 are adhered with an adhesive agent A.

The synthetic resin film for wrapping the shock absorber 3 is made of thermoplastic material, and a thin film of polyethylene, polypropylene, polyamide, polyester, vinyl chloride or the like is instantly wrapping by a vacuum forming method.

As a required characteristic of the shock absorber, when the compression characteristic is compressed as shown in FIG. 3, the load increases with the strain, but even if the compression is performed from a certain place, the load does not increase and the load changes at a constant load. Things are needed. By having such characteristics, in the case of a collision accident such as a vehicle, the shock absorber interposed between the human body and the object does not distort at a rapid speed and absorbs the shock without repulsing greatly. Therefore, it is presumed that damage to the brain and internal organs inside the human body can be reduced. Generally, in the case of a molded foam product formed by a closed mold, it is generally difficult to exhibit the compression characteristics as shown in FIG. 4 and the characteristics as shown in FIG. 3 due to the cell characteristics. Therefore, the compression characteristic becomes elastic, the change in speed at the time of absorbing a shock is large, and the repulsion is also high, so that the human body is likely to be adversely affected. Also, when foaming in the mold, it takes a certain reaction curing time for each mold, so there is a limit to the production quantity,
Long processing time and high cost.

In order to obtain the compression characteristic as shown in FIG. 3, it has been found that it is preferable to compress a vertically long cell in the vertical direction and use a cell having a coarse cell. The reason for this is shown by using a paper cylinder as a model. When compressed in the vertical direction as shown in FIG. 5, the load suddenly rises, and then the structure is destroyed and buckled, and the load suddenly decreases. After that, the phenomenon that the load decreases due to structural destruction occurs randomly and continuously, and until it is completely crushed, it is compressed with a peak that does not exceed the fracture strength level of the material. On the contrary, when the compression is applied from the lateral direction, the load is elastically increased with the compression as shown in FIG. Considering that in the case of rigid polyurethane foam, such cylinders are made up of innumerable combinations, when compressing the cells in the longitudinal direction, when one cell is buckled due to compression and the load drops, another The phenomenon in which the cells are compressed and the load increases is repeated, and the cells are averaged over a larger number of cells, so it is presumed that the compression behavior is as shown in FIG. 7. When the cell is compressed in the lateral direction, the elastically changed objects are combined, so that the cell is elastically changed as a whole, as shown in FIG.
It is supposed to be like. At this time, if the cells are finely clogged, the buckled material is likely to clog between the cells even when compressed in the vertical direction, and the load changes elastically relatively quickly as shown in FIG. There are several possible phenomena. Therefore, in order to obtain the target characteristics, it is preferable that the cells are compressed in the vertical direction and the cells are rough.

The present invention is intended to achieve such an object, and relates to a shock absorber made of a hard resin foam having a coarse and vertically elongated cell structure in which the vertical direction of free foaming is the shock absorbing direction, and one direction is According to a method for manufacturing an impact absorber, which comprises cutting out from a hard resin foam that has been foamed by an open molding die or a continuous foaming facility with lateral restraint, with the vertical direction of foaming being the impact absorption direction. It is a thing. As the resin, polyurethane, phenol resin, and other resins having the same effect can be used, but polyurethane will be described as an example.

In the closed mold foaming of a usual rigid polyurethane foam, the cell size is 0.05 to 0.5 mm.
It is a degree, the shape is likely to be spherical, and the directionality is difficult to be constant, but the coarse and vertically long cell structure in the present invention means that the size of the cell is relatively larger than usual and the longitudinal diameter is horizontal. In addition to a structure with a larger diameter, a foam structure with a relatively large longitudinal diameter is often included even if the individual cell diameters are not uniform. In the present invention, the size of the cell is preferably 0.15 mm to 1.5 mm on average with a short diameter of 0.2 mm to 1 mm.
The degree is more preferable. If the cell becomes too large, the flat portion of FIG. 5 in the load / strain characteristic during compression will vary greatly, which is not preferable. A cell aspect ratio of 1.3 / 1 or higher is good, and 1.5 / 1
The above is more preferable.

As an example for obtaining the shock absorber of the present invention, it can be manufactured as follows. It is performed by a free-foaming process by a batch foaming method using a mold whose one direction (usually upward direction) is opened or a continuous foaming method (usually left and right sides are constrained). Although it is difficult to give directionality to cells by mold foaming, in the case of large-scale batch foaming in the present invention or blocks that are continuously foamed, the cells become vertically long because they are bound only in the horizontal direction (Fig. 10) It is possible to manufacture a shock absorber made of a rigid polyurethane foam having a vertically long cell structure by cutting and molding from the foam thus obtained with the vertical direction of foaming as the shock absorption direction in the product. it can. By arranging the side guide plates so as to be gradually narrowed during the continuous foaming, it is possible to further promote the lengthening of the cells.

In the foaming process, by adding a silicone-based surfactant having a foam-breaking effect to the raw material for the rigid polyurethane foam, the foam produced in the foaming process is destabilized, and several foams are removed. It is possible to obtain a coarse foam structure. As such a silicone-based surfactant, S manufactured by Toray Dow Corning Silicone Co., Ltd.
F2964 or Y-4499 manufactured by Nippon Unicar Co., Ltd. can be used. As the urethane material, a rigid polyurethane foam can be usually used. Since the semi-hard or soft urethane material is an elastic cured product, it is difficult to obtain the above characteristics.

Since the polyol component and the isocyanate component are ordinary materials, they are omitted.

As a characteristic required for automobile interior materials, the US Federal Motor Vehicle Safety Standard (FMVSS208) specifies that when a vehicle collides with a moving barrier at a speed of 32 km / hour against a side collision, the resultant acceleration of the chest is 3 m. It is stipulated that 60G should not be exceeded for a time of more than a second, but in order to satisfy this stipulation, as static compression test characteristics, experimentally (1) Withstand load 350kg or more (2)
Compressive displacement 50 mm or more (compression mutation rate 70% or more) (3)
It has been found that a buffering efficiency of 70% or more is required.

Therefore, in manufacturing the shock absorbing material and the skin of the present invention, it is necessary to take care so that an export vehicle for the United States passes the Federal Motor Vehicle Safety Standard (FMVSS208).

From the above-mentioned viewpoint, the skin-reinforcing material of the protective layer has a compressive strength of 100 kg / cm ² or more or a bending strength of 80.
An outer surface layer of at least kg / cm ² is desirable.

On the other hand, as the polyurethane foamed resin having good impact absorption performance, a compressive strength of 0.5 to 10 kg / cm ² ,
A rigid foam of rigid polyisocyanurate foam or open-celled rigid polyurethane foam having a buffering efficiency of 60% or more is desirable, but when an isocyanate trimer is used, a hydroxy-containing compound is added to 5 parts by weight of a hydroxy-containing compound based on 100 parts by weight of the isocyanate trimer. By adding up to 22 parts by weight, an excellent shape-retaining property was obtained. Apparent density 0.04 to 0.1 g /
cm ³ is desirable.

The molded body integrally formed with the skin of the shock absorbing material has a withstand pressure load of 150 kg or more, a compression change rate of 60% or more,
It is desirable to design the buffer efficiency to be 60% or more.

FIG. 13 shows a compression load variation curve. In FIG. 13, the buffer efficiency% is the buffer efficiency% = (OABCO
Area / ODBCO area) × 100.

US Federal Motor Vehicle Standard (FMVSS208)
Needless to say, it is of course necessary to cut out and mold the foamed cells of the rigid polyurethane foam having a vertically long foamed cell structure so that the longitudinal direction of the foamed cells coincides with the impact absorption direction.

[0022]

Function: Since the surface of the shock absorber formed by cutting out from the free foam of rigid polyurethane foam is wrapped with the synthetic resin film, the contamination of the inside of the vehicle due to the powder drop of the rigid polyurethane foam due to the vibration of the vehicle is eliminated.

[0023]

EFFECTS OF THE INVENTION Between the shock absorber in which a synthetic resin film is wrapped to prevent the powder from falling on the surface of the shock absorber formed by cutting from a free foam of rigid polyurethane foam, and the iron plate portion (outer plate portion). Adhesion with an adhesive produced an effect of eliminating rubbing noise.

[Brief description of drawings]

FIG. 1 is a sectional view of a conventional door trim.

FIG. 2 is a cross-sectional view of a door trim in which the shock absorber of the present invention is wrapped with a synthetic resin film.

FIG. 3 is a compression characteristic diagram required for a shock absorber.

FIG. 4 is a compression characteristic diagram of molded urethane foam.

FIG. 5 is a model diagram in which a cylinder is vertically compressed.

FIG. 6 is a model diagram in which a cylinder is laterally compressed.

FIG. 7 is a model diagram for vertically compressing an innumerable array of cylinders.

FIG. 8 is a model diagram of laterally compressing an innumerable array of cylinders.

FIG. 9 is a model diagram of compressing innumerable cylinders in the vertical direction when the cylinders are too thin.

FIG. 10 is an enlarged photograph of a coarse and vertically long cell structure manufactured by the present invention.

FIG. 11 is a schematic view of a production system using the continuous foaming equipment of the present invention.

FIG. 12 is a compression characteristic diagram of a shock absorber made of a rigid polyurethane resin foam having a coarse and long cell structure manufactured according to the present invention.

FIG. 13 is a diagram showing a compression load displacement curve of an integral molded body of a shock absorber and a skin made of the rigid polyurethane foam manufactured by the present invention.

[Explanation of symbols]

1 Skin 2 Shape Retaining Skin Reinforcing Material 3 Foam Shock Absorbing Material 4 Car Door Outer Panel 5 Stirrer 6 Endless Conveyor 7 Continuous Polyurethane Foam Hard Polyurethane Resin Foam 8 Shock Absorbing Product A Adhesive L For Powder Fall Prevention Polyurethane foam surface wrapping

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shigetoshi Mimura 3 Yoshigayama, Miyoshi-cho, Nishikamo-gun, Aichi Prefectural Automobile Parts Technology Center, Toyo Tire & Rubber Co., Ltd. (72) Inventor Yuji Aoki Nishikamo-gun, Aichi 3 Miyoshi-cho, Otsuchi, Ikagayama 3 Toyo Tire & Rubber Co., Ltd. Auto Parts Technology Center (72) Inventor Sadakuni Shioya 982 Kaneda, Atsugi, Kanagawa Toyo Soflan Co., Ltd.

Claims (2)

[Claims] 1. A shock absorber made of hard polyurethane foam in a side / front / rear collision / shock absorbing member attached to an automobile interior is cut out from free foam and molded, and the surface of the shock absorber is made of a synthetic resin film. A method for producing a side impact shock absorber for a vehicle, characterized in that the rigid polyurethane foam is prevented from falling off by wrapping. 2. The side impact shock absorber for a vehicle according to claim 1, wherein the rigid polyurethane foam having a vertically long foam cell structure is cut and formed so that the longitudinal direction of the foam cells coincides with the impact absorption direction. Production method.