JPS58101044A - Grip with high-density hard shell - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a grip for a vehicle such as a steering wheel for an automobile.

As shown in FIG. 1, a conventional grip such as a steering wheel for an automobile includes a handle 1 made of a core metal 3 made of steel and a plastic layer 2 covering the core metal. Typical materials for the plastic layer 2 are hard polypropylene resin and soft integral polyurethane foam. Among these, the former is a dense hard resin layer, which increases the weight of the product and is relatively prone to cracking due to impact, especially during cold resistance tests.

Therefore, great care must be taken during design to achieve constant characteristic values.

Moreover, there are inconveniences such as the feeling of being too cold when held in cold weather. In the latter case, the grip feels perfect, but the resin layer only contributes to the feel and does not function as a strength layer at all. For this reason, it is necessary to provide all the required strength with the core metal, and it is necessary to use a core metal with a large diameter or high strength, which is disadvantageous as it increases weight and cost.

The present invention aims to overcome these disadvantages).

To explain this based on FIG. 2, the automobile steering wheel 1 consists of a high-density hard inner layer 4 formed around the outer circumference of the core metal 3. It consists of a foam layer 5 formed on the outside and a high-density hard outer skin 6 forming the outermost layer, and the outer skin 69 foam layer 5 and inner layer 4 are made of the same rigid polyurethane foam,
They are formed simultaneously and in one piece. Furthermore, the foam layer 5 has a much lower density than the outer skin 1 and the inner layer 4.

In this example, with this structure, in addition to the mandrel 3, the outer skin 6 and the inner layer 402 are formed as strength layers having a substantially ring-shaped cross section. As a result, the mandrel 3 can be made as thin and lightweight as possible, and can even be omitted in some cases. Moreover, since the outer skin 6 is made of a high-density hard layer of polyurethane foam, the impact resistance during cold weather is significantly improved. Furthermore, since a foamed layer having a considerably low density is formed between the two strength layers, the weight of the entire resin layer can be significantly reduced. Moreover, since this foam layer forms a good heat insulating layer, the feel in cold weather is also improved.

To manufacture a handle, all the components of rigid polyurethane foam need to be measured, mixed, and placed into a mold cavity having the desired product shape.Therefore, a commonly used low-pressure stirring type foaming machine for rigid urethane is used. Alternatively, a high-pressure injection mixing type foaming machine may be used.

The mechanism for obtaining this cross section will be explained as follows.

The rigid polyurethane foam raw materials used in the present invention employ blowing agents of the conventional type, ie volatile low-boiling organic liquids having a boiling range of 20 DEG C. to 70 DEG C. Examples include trichlorofluoromethane, methyl chloride, dibromotetrafluoroethane, and the like. Water is included as a blowing agent, especially when it is desired to reduce the density of a high-density hard solid layer. The raw materials for rigid polyurethane foam that have been blended and prepared containing these low-boiling point organic liquids are mixed using the above-mentioned ordinary foaming machine, and then molded into a mold with a desired product shape and a cored metal. When the mixture is injected and discharged, the low-boiling organic liquid immediately begins to vaporize due to an exothermic reaction, and the urethane raw material foams and is filled into the mold.

However, when foaming occurs due to an exothermic reaction within the mold, the heat generated during the reaction moves from the mold wall corresponding to the outer skin of the product in the mold having the desired product shape, causing the injection and discharge liquid to come into contact with the mold wall. The temperature rise is delayed, and foaming in the area is also suppressed.

That is, in this part, the vaporization of the low-boiling organic liquid is delayed and suppressed compared to the temperature rise accompanying the exothermic reaction in the central part.

Therefore, if the reaction is completed at a time when there is a temperature gradient in the reaction system under these conditions, a high-density, hard outer skin can be formed over the entire outer peripheral surface of the product.

The same explanation applies to the core metal portion.

Of course, it is also possible to increase the thickness and density of these high-density hard strength layers by simultaneously increasing the foaming pressure during foaming of the urethane stock solution in the mold. The foam layer has a foaming ratio of 1.6 to 10 times the weight, and the strength of the strength layer is selected in the range of 1 to 4 times the strength of a conventional polypropylene product of the same shape as the strength of the molded product. is preferred.

Note that, unlike the above embodiment, the strength layer can also be a single layer. In this case, the deposit will also be omitted. In either case, the strength layer is the composition.

By appropriately selecting the reaction conditions, it is possible to freely create materials with wall thickness and physical properties that match the required strength. Moreover, by using a hard elastomer as the material, the outer surface becomes tougher and less prone to scratches.

In addition to steel, resin such as nylon cord can also be used for the core metal.

Further, the grip of the present invention includes grip parts for automobiles and vehicles, grips for handles and seats of bicycles, automobiles, etc.

The present invention will be explained in more detail below based on Examples.

Example: Mixing liquids A and B components shown in Table 1 were mixed and prepared, using a normal high-pressure injection mixing foaming machine, and placing a mandrel in a $7 mold made of metal. After 5 minutes of injection and foaming, the molded product was removed from the mold, and its cross section was measured, and the results shown in Table 2 were obtained. This product showed a 50% improvement in polypropylene, compressive and flexural strength.

Table 1 (compounded liquid) A component 4 parts by weight PE-45070.0 Mitsui Nisso Tsureta 2-Polyol M
N-100020,0// NP-'300 10.0 Sanyo Chemical ■Crosslinking agent■No5420 2.0 Nippon Unicar Han foam stabilizer KAO1'kl 1
．． 0 Kao Shichikke Plant (E) Amine Catalyst U-100
0,1 Nitto I b plexus - Sume catalyst freon = 11u 2
0.0 Daikine Kikumori Leon Foaming Agent Pigment
2 B component JP-A-58-101044
(58-1O1044(3) Mitsui Nisso Tsureta'A
Blending ratio of scooped polymer isocyanate (weight ratio)
A/B=100/86 (2) Internal layer 1.2
0.82 - (3) Foam layer 4.5 0
．． 20-(4) Core metal (pipe shape 1smm)
850 (5) Product weight
1110 (6) Total urethane amount 2
60(7) Molded product compressive strength (kg/mm)
10.3(8)〃Bending〃(〃)2.9

[Brief explanation of drawings]

Figure v1 is a sectional view showing a conventional handle. FIG. 2 is a sectional view showing an embodiment of the present invention. -1...
...Handle, 3... Core metal 4...
...Inner layer, 5...Foam layer 6...
・Outer skin patent applicant Tokyo Seat Co., Ltd.

Claims (1)

[Claims] A high-density product consisting of a high-density, hard outer shell and a hard foam layer inside the outer shell, and the outer shell and the foam layer are integrally molded from rigid polyurethane foam, and the outer shell serves as a strength layer. □Grip with hard outer skin. −J−=to