JPS6149330B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a shock absorbing material, and more particularly to a shock absorbing material that exhibits sufficient functionality even at low temperatures. It has been known to use cured polyurethane as a shock absorbing material. However, since impact cushioning materials are widely used in automobiles, other transportation systems, and various machines such as dart bags, they are often exposed to environments with severe temperature changes, and there is still no satisfactory material that can withstand use particularly at low temperatures. Ta. The inventors of the present invention have conducted extensive research in order to overcome the drawbacks of conventional impact cushioning materials and develop a new impact cushioning material that exhibits sufficient functionality even at low temperatures. As a result, they discovered that a cured product obtained by blending and curing a polyol, a diisocyanate compound, and a specific liquid polybutadiene rubber has the desired function, and has completed the present invention. That is, the present invention provides a polyol that has hydroxyl groups at both ends of the molecule and has a fine structure of 1,4
- Adding a liquid polybutadiene containing mainly bonds, a curing catalyst and a blowing agent to obtain a blend (), adding a diisocyanate compound to the blend () to obtain a blend (), and then adding the blend () to the blend (). The present invention provides a hardened impact cushioning material. In the present invention, liquid polybutadiene rubber is first added to polyol. The blending ratio of the polyol and the liquid polybutadiene rubber is not particularly limited, but it is usually preferable to use 10 to 70 parts by weight of the liquid polybutadiene per 100 parts by weight of the polyol. In addition, the polyol used in the present invention can be selected from various types depending on the intended use of the final product and is not particularly limited, but usually polyethers such as polyoxypropylene glycol and polyoxypropylene polyoxyethylene glycol are used. Polyols or polyester polyols such as polyethylene adipate glycol are used.
On the other hand, liquid polybutadiene rubber has fluidity at room temperature and can form a three-dimensional network structure through appropriate chemical treatment such as curing treatment. , so-called telechelic liquid rubbers are preferred, especially those having a hydroxyl group at the molecular end,
In addition, a liquid polybutadiene rubber whose microstructure mainly consists of 1,4 bonds is used. In the present invention, liquid polybutadiene rubber is added to the above-mentioned polyol, or at the same time, a curing catalyst and a blowing agent are added to form a compound ().
Prepare. Suitable curing catalysts include di-n-butyltin dilaurate, tri-n-butyltin chloride, ferric chloride, cobalt naphthenate, antimony trichloride, triethylenediamine, or triethylamine, and blowing agents include organic foaming agents. The foaming agent may be either a foaming agent or an inorganic foaming agent, and is not particularly limited, but trichloromonofluoromethane, dimethylene chloride, and the like are preferred. The amount of curing catalyst and blowing agent added varies depending on various conditions, but a small amount is sufficient for both.
For example, 0.1 to 1.0 parts by weight per 100 parts by weight of polyol will function satisfactorily. On the other hand, the amount of the foaming agent added varies depending on its type, but it is usually added at a rate of 2 to 10 parts by weight per 100 parts by weight of the polyol. In the present invention, polyol, liquid polybutadiene rubber, a curing catalyst, and a blowing agent are mixed thoroughly by suitable mechanical means to form a compound (2). Next, a diisocyanate compound is added to this blend () and mixed uniformly to prepare a blend (). Although there is no particular restriction on the proportion of the diisocyanate compound, it is usually preferably in the range of 50 to 200 parts by weight based on 100 parts by weight of the polyol in the mixture. In addition, various diisocyanate compounds can be selected depending on the use of the final product, but for example, 4,
Examples include 4'-diphenylmethane diisocyanate, tolylene diisocyanate, naphthylene diisocyanate, and hexamethylene diisocyanate. Furthermore, it is also possible to use modified products of 4,4'-diphenylmethane diisocyanate. In the present invention, it is necessary to add the diisocyanate compound after preparing the above formulation (). If a diisocyanate compound is added at the same time when preparing the compound (2), it becomes a semi-cured or highly viscous product that is difficult to handle, and the resulting cured product becomes extremely difficult to mold. In the present invention, an impact cushioning material is further obtained by curing the above-mentioned compound (2). This curing reaction proceeds well even at room temperature, but
The process will proceed even more rapidly if it is carried out under heating at a temperature of about °C. Note that during this curing reaction, the above-mentioned curing catalyst acts effectively and the reaction proceeds smoothly. The shock-absorbing material obtained as described above exhibits excellent shock-absorbing properties, and the shock-absorbing performance is significantly improved, especially at low temperatures, compared to conventional shock-absorbing materials. Therefore, the impact cushioning material of the present invention is extremely useful as various impact cushioning materials for automobile bumpers, railways, ships and other transportation systems, and various types of machinery. Next, the present invention will be explained in more detail using comparative examples and examples. Comparative example 1 Polyoxypropylene glycol (OH value: 35
mg KOH/g) 1,4-butanediol 16 parts by weight, dibutyltin dilaurate per 100 parts by weight
A blend was obtained by uniformly mixing 0.09 parts by weight, 0.27 parts by weight of a mixed solution of triethylenediamine and dipropylene glycol (mixing ratio 1:2 (weight ratio)), and 4 parts by weight of trichloromonofluoromethane.
Modified 4,4'-diphenylmethane diisocyanate (manufactured by Nippon Polyurethane Co., Ltd., trade name: Millionate MTL, 29% by weight of unreacted isocyanate groups) (hereinafter referred to as "modified MDI") based on 100 parts by weight of this compound.
It is abbreviated as ) 52 parts by weight and mechanically mix uniformly.
A cured product (1) was obtained at a curing temperature of 0° C. and a curing time of 2 minutes. Table 1 shows the physical properties of this cured product at various temperatures. Example 1 Polyoxypropylene glycol (OH value: 35
mg KOH/g) 70 parts by weight, liquid polybutadiene having hydroxyl groups at both ends of the molecule (OH content:
0.83 meq/g, viscosity 50 poise/30°C) (manufactured by Alco Chemical Co., Ltd., product name: polybd R-45HT, number average molecular weight 2800) 30 parts by weight, 1,4-butanediol 16 parts by weight, dibutyltin dilaurate 0.09 parts by weight 0.27 parts, mixed solution of triethylenediamine and dipropylene glycol (mixing ratio 1:2 (weight ratio))
Part by weight and 4 parts by weight of trichloromonofluoromethane were uniformly mixed to obtain a blend (). Add 52 parts by weight of modified MDI to 100 parts by weight of this mixture () and mechanically mix it uniformly to form a mixture ().
A cured product (2) was obtained at a curing temperature of 30° C. and a curing time of 2 minutes. Table 1 shows the physical properties of this cured product at various temperatures. Example 2 The same operation as in Example 1 was performed except that 70 parts by weight of polyoxypropylene glycol in Example 1 was replaced with 80 parts by weight, and 30 parts by weight of liquid polybutadiene was replaced with 20 parts by weight, and a cured product ( 3) obtained. Table 1 shows the physical properties of this cured product at various temperatures. Example 3 The same operation as in Example 1 was performed except that 70 parts by weight of polyoxypropylene glycol in Example 1 was replaced with 90 parts by weight, and 30 parts by weight of liquid polybutadiene was replaced with 10 parts by weight, and a cured product ( 4) obtained. Table 1 shows the physical properties of this cured product at various temperatures.

[Table] As is clear from Table 1, as the content of liquid polybutadiene increases, the temperature change in each physical property value of the cured product decreases. especially
It can be seen that the temperature change in 100% tensile stress and hardness is small, and therefore it has more effective impact buffering ability even at low temperatures.

Claims (1)

[Claims] 1. A compound () is obtained by adding a liquid polybutadiene rubber having hydroxyl groups at both ends of the molecule and having a microstructure mainly consisting of 1,4 bonds, a curing catalyst, and a blowing agent to a polyol. , an impact cushioning material obtained by adding a diisocyanate compound to the blend () to obtain a blend (), and then curing the blend (). 2. The impact cushioning material according to claim 1, which is blended with 100 to 70 parts by weight of liquid polybutadiene rubber and 50 to 200 parts by weight of a diisocyanate compound to 100 parts by weight of polyol. 3. A patent claim in which the polyol is either a polyether polyol or a polyester polyol, and the diisocyanate compound is any one of 4,4'-diphenylmethane diisocyanate, tolylene diisocyanate, naphthylene diisocyanate, and hexamethylene diisocyanate. The impact cushioning material according to item 1. 4 Liquid polybutadiene rubber has a number average molecular weight of 500
The impact cushioning material according to claim 1, which is a liquid polybutadiene rubber having a molecular weight of 8000 to 8,000. 5. Claim 1 in which the curing catalyst is any one of di-n-butyltin dilaurate, tri-n-butyltin chloride, ferric chloride, cobalt naphthenate, antimony trichloride, triethylenediamine, and triethylamine. Shock cushioning material as described in section.