JPS63105047A - Shock-absorbing material - Google Patents

Abstract

PURPOSE:To provide an inexpensive shock-absorbing material composed of an elastomer having a shock absorption ratio of higher than a specific level and a needle penetration falling within a specific range and suitable for embedding in the heel of sports shoes such as running shoes, tennis shoes, basketball shoes, etc. CONSTITUTION:The objective shock-absorbing material is composed of an elastomer having a shock absorption ratio of >=40% and a needle penetration of 20-70 and produced e.g. by compounding (A) PVC (polvinyl chloride for paste) with a stabilize (butyltin laurate compound) and a plasticizer (DOP) or (B) a liquid polyisoprene rubber with a crosslinking agent (tert-butyl cumyl peroxide) and spindle oil, etc. A sufficiently satisfactory results can be obtained in the protection of heel and knee by using a shock-absorbing material composed of an elastomer having a shock absorption ratio and needle penetration satisfying the above conditions and embedding the material in the heel of sports shoes.

Description

DETAILED DESCRIPTION OF THE INVENTION A) Field of Industrial Application The present invention relates to a shock absorbing material, and particularly to a shock absorbing material suitable for being embedded in the heel of sports shoes.

2. Description of the Related Art Various sports shoes designed with functionality in mind have been widely put into practical use for running, jogging, tennis, basketball, and other sports.

However, at the time of contact with the ground during a sports competition, an impact force of about three times the body weight is applied to the sole of the shoe the athlete is wearing, especially the heel, each time the athlete touches the ground. The reality is that he has injured his heel and knee.

This tendency has become more and more noticeable as roads and stadium grounds have been made harder, and countermeasures have been urgently needed.

In view of the above circumstances, recently a few shock absorbing materials such as elastomer foams and viscoelastic materials have been proposed and some have been put into practical use, and although they have achieved some degree of effectiveness,
It did not fully achieve the intended purpose and had drawbacks such as being too expensive.

C) Purpose The purpose of the present invention is to eliminate the drawbacks of conventional shock absorbers and to provide a shock absorber that does not damage the heel or knee of the wearer even when used for the heel of a shoe sole, etc. It is something.

2) Means for solving the problem The shock absorbing material of the present invention is made of an elastomer having a shock absorption rate of 40% or more and a penetration degree of 20 to 70.

Below, the method for manufacturing the impact absorbing material of the present invention and the advantages of the obtained impact absorbing material will be compared with a control example.

Invention l Same 2 Same 3 Same 4 Same 5 PVC"' 100 100 100 - Stabilizer*"555- Plasticizer*" 300 400 500 -
~Liquid IR*' -10010
0 cross-linking agent*'-1010 spintolum origin
-150200*“: Polyvinyl chloride for paste (contains vinyl acetate 1t10χ, P=tsoo)
*2: Butyl/tin/laurate compounds*3:
oop *': i-form polyisoprene rubber *S, tert-butyl cumyl peroxide A kneaded product was prepared according to the above formulation, and in the present invention 1.2.3,
The obtained paste was cast on a metal plate and heated at 170°C for 5 minutes to gel it to prepare a sample. A sample was prepared by tightening and vulcanizing.

At the same time, as a control example 1, a reaction product of a linear polyol and an aromatic isocyanate, and unreacted OH
Comparative Example 2
As Example 3, a foam of ethylene vinyl acetate copolymer (containing vinyl acetate, FF115χ, specific gravity 0°25) was prepared, and as Control Example 3, a reaction addition type silicone gel was prepared.

Incidentally, all of the above control examples are commercially available and have been put into practical use. Using each of the above samples, the following physical properties, which serve as a guideline for use as a shock absorbing material, were measured.

Present invention 1 45 20 15 30
2 50 42 3B 23〃35
5575518 4 48 25 20 32 55
5666620 Control example 1 35 8 5 15〃22
5 0048 〃3 50 32 3B 12*l
: Polyurethane hemisphere with a radius of 15 mm (Katasa 10.
JIS
attached to the lower end of an aluminum cylindrical body (weight 4,000 g), with the polyurethane hemisphere surface facing down, thickness 101 mm,
It was dropped from 100m+n onto a sample of size 1001 square, and the deceleration (GO) was measured.

Under exactly the same conditions, it was dropped onto a steel plate, the deceleration G0 was measured, and the value calculated from the following formula was taken as the impact absorption rate (χ).

Note that the temperature at the time of measurement was 25°C.

* ”: According to JIS X2530 - Petroleum Asphald Needleability Test Method - Needle diameter 2 mm. The temperature at the time of measurement was 25°C and -10°C.

*3: On a sample with a thickness of 10III11 and a size of 100mm square, the radius? , 5mm+, weight 14g steel balls 50
Dropped from a distance of 0mr@, and the bounce at that time
(t mm) was measured, and the value calculated from the following formula was defined as impact resilience (%).

Note that the temperature at the time of measurement was 25°C.

　X100 The above 8 types of samples have a thickness of 8 mm and a long side of 60 nm.

I made a sample of 50 pieces on the short side, buried it in the heel of my jigging shoes, and ran it on the road for about 10 km every day for a total of 600 samples.
I ran km. The results were as follows.

Present invention 1 No abnormality in heels and knees〃 2 〃 〃 3 〃 〃 4 〃 〃 5〃 Control example 1 I felt abnormality in my knees after running about 500 km.

〃 2 After running about 400 km, I started to feel something wrong with my knees.

~3 No abnormality in heels or knees.

From the above, the shock absorption rate is 40℃ or higher, and the needle size is 20 or higher (
25° C.), it was found that sufficiently satisfactory results for heel and knee protection could be obtained. Such a result is
The same applies to running shoes, tennis shoes, basketball shoes, etc.

In addition, the penetration is thick (I see, it becomes soft and good results can be obtained, but if it is embedded in the heel of a shoe, it will lose its shape, so it must be tightly adhered with a soft and strong plastic film. However, if the penetration exceeds 70, it will be too soft and difficult to handle.

Repulsion resilience does not necessarily have a clear correlation with the intended purpose, so it was not considered as a component of the gist of the present invention.

e) Effects If a shock absorbing material made of elastomer with a shock absorption rate of 402 or more and a penetration degree of 20 to 70 is used by embedding it in the heel of a shoe, for example, you can run a considerable distance every day and continue for a long time. It has the characteristics that it does not damage heels, knees, etc., and can be obtained at low cost because it does not require the use of particularly expensive materials such as silicone.

Claims (1)

[Claims] A shock absorbing material made of an elastomer with a shock absorption rate of 40% or more and a penetration degree of 20 to 70.