JPH06129420A - Urethane roller - Google Patents

Abstract

PURPOSE:To improve the adhesive strength of an urethane roller whose formation material is thermoplastic urethane elastomer, to a core metal. CONSTITUTION:In the case of an urethane roller made up by furnishing outwardly urethane elastomer to the outer periphery of a core metal such as a metal rotation shaft or a bearing, the urethane elastomer consists of thermoplastic elastomer and an isocyanate compound having more than two isocyanate groups, and drastic adhesion power improvement is attained by the addition of the isocyanate compound having more than two isocyanate groups.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a urethane roller, and to an improvement of the urethane roller.

[0002]

2. Description of the Related Art A roller having a cored bar or an outer periphery of a bearing covered with an elastomer layer has excellent strength, low noise and low vibration, and is therefore used in various fields such as FA and OA. . Among them, the roller whose elastomer is urethane is superior to other elastomer rollers because of the abrasion resistance and high strength of urethane.

[0003]

[Problems of the prior art] Incidentally, there are two types of urethane elastomers, a two-liquid mixing type and a thermoplastic type, both of which are used as the elastomer material of the urethane roller. Since the product undergoes a chemical reaction due to high molecular weight in the molding process, the adhesive strength of the urethane elastomer to the core metal etc. is good, but since the casting and molding must be completed by the end of the reaction, the molding process becomes complicated. There was a drawback in terms of economy. On the other hand, the latter thermoplastic type is easy to mold because it can be molded by injection molding, etc., but on the other hand, it does not cause a chemical reaction during molding, so the adhesive strength to the core metal etc. is poor and the product reliability is low. was there.

[0004]

SUMMARY OF THE INVENTION In view of the above problems, the present invention provides a urethane roller which has improved adhesiveness to a core and is more reliable, even though a thermoplastic urethane elastomer which is easy to mold is used. It was made for the purpose of providing.

[0005]

That is, the urethane roller of the present invention is a urethane roller in which a urethane elastomer is coated on the outer periphery of a metal core such as a metal rotating shaft or a bearing, and the urethane elastomer is a thermoplastic elastomer. It is characterized by comprising an isocyanate compound having two or more isocyanate groups.

[0006]

In the present invention, as the core metal of the urethane roller, various metal members used as roller shafts such as metal shafts having a circular cross section or bearings can be applied. The thermoplastic urethane elastomer used in the present invention includes polyesters, polyethers, carbonates, etc. having two or more active hydrogens in one molecule, and diols having two or more active hydrogens in one molecule.
Tolylene diisocyanate having two or more isocyanate groups in one molecule reacted with diamine, P
-Phenylenediisocyanate, diphenylmenthadiisocyanate, naphthalene diisocyanate and the like are those reacted with a diisocyanate compound.

When molding the roller, the above-mentioned thermoplastic urethane elastomer and an isocyanate compound having two or more isocyanate groups in one molecule are dry-blended and molded by an ordinary injection molding machine. The metal rotating shaft or the core metal such as a bearing is subjected to sandblasting, degreasing and cleaning treatment, and adhesion treatment on its surface according to a conventional method. The roller formed by coating the core metal with the urethane elastomer is aged at room temperature or at a temperature of 110 ° C. or less for 24 to 7 days.

In the present invention, the reason why the blend of the thermoplastic urethane elastomer and the isocyanate compound having two or more isocyanate groups in one molecule is used for forming the roller is as follows.

That is, the thermoplastic urethane elastomer is 1
Since a urethane group is produced by equivalently blending a polyol having two or more active hydrogens in the molecule with a toluylene diisocyanate having two or more isocyanate groups in one molecule, there is no terminal NCO. High polarity and poor reactivity. Further, since a chemical reaction does not occur by heating, even if there is a mechanical and physical adhesive force, the adhesive force to the core metal or the like is poor.

Therefore, two isocyanate groups are contained in one molecule.
It is possible to improve the adhesive force by adding an isocyanate compound having a number of more than one and forming a chemical secondary bond between the high polarity of the isocyanate and the excellent reactivity and the metal surface containing active hydrogen. Since the blended polyisocyanate self-polymerizes to form a tertiary polymer, it is possible to freely adjust the adhesive layer forming film from an elastic and tough film to a hard elastic film close to a metal depending on the addition amount.

Since the isocyanate compound blended with the thermoplastic urethane elastomer undergoes a polyaddition reaction not only between the molecules but also at the interface with the metal, a very good adhesive force is obtained and the peeling between the metal surface and the urethane coating layer is prevented. Does not happen.

[0012]

Embodiments of the present invention will be described below.

(Example) As a thermoplastic urethane elastomer, CROSNATE EM30 (same as above) as an isocyanate compound having two or more isocyanate groups in one molecule per 100 parts by weight of Resamine P4590 (manufactured by Dainichiseika)
20 parts by weight were dry blended. Next, a 6204 zz bearing having an outer diameter of 47 mm was prepared as a core metal, the surface was sandblasted, washed with trichlorethylene, and Chemlok 218 (manufactured by Road Far East Co., Ltd.) as an adhesive was applied and dried.

The above bearing is set in an injection mold,
The dry blended urethane elastomer was supplied to an injection molding machine, and the nozzle temperature was set to 195 ° C, the front temperature to 190 ° C, the middle temperature to 180 ° C, and the rear temperature to 170 ° C, and the injection pressure (gauge pressure) was 15.3 MPa (150 kg / cm). ² ),
A urethane roller was obtained by injecting at a holding pressure (same as above) of 7.65 MPa (75 kg / cm ² ) and cooling for 60 seconds. The obtained urethane roller was removed from the mold and aged at 110 ° C. for 24 hours.
The urethane roller has a dimension of 4 m in thickness of the outer urethane layer.
It was m and the width was 18 mm.

(Comparative Example) As a thermoplastic urethane elastomer, a urethane roller material was prepared with only 100 parts by weight of Resamine P4590 (manufactured by Dainichiseika). Next, this urethane roller material was supplied to a mold as in the example to obtain a urethane roller having the same shape as that of the example.

The urethane rollers obtained in the above Examples and Comparative Examples were pressed against metal running wheels at a pressure of 6.1 N (60 kgf) at a peripheral speed of 100 m / min to test the durability. There was no abnormality even after the lapse of time, and the test was terminated at this point, whereas in the comparative example, the urethane layer was peeled off and damaged after 281 hours had elapsed. Further, when the pressing force of the metal running wheel was increased to 7.1 N (70 kgf) and the same test was conducted, peeling damage occurred in 690 hours in the example, whereas peeling damage occurred in only 39 hours in the comparative example. The durability of the example was confirmed.

[0017]

As described above, according to the present invention, even though the thermoplastic urethane elastomer is used, the urethane roller having excellent adhesion to the core metal and excellent durability can be prepared easily. is there.

Claims (1)

[Claims] 1. A urethane roller in which a urethane elastomer is coated on the outer periphery of a metal core such as a metal rotary shaft or a bearing, wherein the urethane elastomer comprises a thermoplastic elastomer and an isocyanate compound having two or more isocyanate groups. Characteristic urethane roller.