CS261580B1 - A method for reducing volatile matter in bonded joints - Google Patents

Abstract

The method solves the problem of reducing the content of volatile flakes in glued joints of thermoplastic rubbers with rubber, with polyamide textile and with other polymer materials. A mesh of natural, artificial or metal fibers is inserted between the glued surfaces, the mutual distance of which is less than 10 mm.

Description

SUMMARY OF THE INVENTION The present invention provides a method for reducing the content of volatiles in the bonded joints of thermoplastic rubbers with rubber, polyamide textile, and other polymeric materials, wherein the effect of heat and pressure in the joint results in the release of volatiles.

When bonding thermoplastic rubbers to rubber, polyamide textile and other polymeric materials, a very good bond can be achieved by simply applying heat and printing without the use of adhesives or other bonding materials. It has been found experimentally that the strength of the joints thus produced increases with temperature and pressure and depends on the composition of the two materials to be joined. An important role is the content of volatile substances such as water, solvents, low molecular weight additives in polymers, etc., because during the gluing process these substances become gaseous and form cavities or a large number of bubbles in the joint. This significantly reduces the quality of the joint. The negative effect of volatile substances can be compensated by increasing the pressure and temperature by joining, drying and coating the surfaces to be bonded prior to bonding, chemical surface treatment or reducing the volatile matter content in the production of thermoplastic rubbers. These processes increase the cost of joining while increasing the time and energy consumption of the joining.

These drawbacks are solved by a method for reducing the content of volatile substances in the bonded joints of the thermoplastic rubbers with rubber and polyamide textile according to the invention, which consists in inserting between the bonded surfaces forces of natural, artificial or metal fibers whose mutual distance is less than 10 mm.

A network of natural, man-made or metal fibers prevents the formation of bubbles and voids of volatile substances that arise when bonding surfaces to be bonded. Along the individual fibers, the pairs of volatile substances are forced into the space outside the glued joint, which has a positive effect on the quality of the joint. The release of large amounts of volatile substances substantially reduces the time required to achieve the desired strength

- 2 glued joints.

Example 1 _{281 58 (i}

The rubber liner of the category A conveyor belt was bonded to TR 370 + 371 thermoplastic rubber at a temperature of 130 ° C and a compression pressure of 4 MPa. A peel strength of 5.5 kNm @ 2 was achieved. Using a fine cotton fiber mesh of 1 mm distance, a peel strength of 9.5 kNm was achieved under the same physical conditions and for the same materials.

Without the use of a cotton fiber net, 1 to 20 mm bubbles per 100 mm area were produced. These defects did not occur when using a fine cotton fiber net. Example 2

Rubberized polyamide textile PA 700, which forms a frame of textile reinforced conveyor _belts} were mutually linked at 145 ° C and a pressure of 2 MPa by a film thickness of 1 mm, made from thermoplastic rubber TR 370 + 371 "lap joint was 100 x 200 mm. The resulting tensile strength of the joint was 320 N mm.

Using a 1 mm fine cotton fiber net, a tensile strength of 450 R mm was achieved under the same physical conditions and for the same materials.

Example 3

When bonding the rubber coating of category M with thermoplastic rubber TR 392 at 130 ° C, a peel strength of more than 10 kNm -1 could only be achieved by applying a compression pressure of more than 4 MPa. When using a mesh of 0.1 mm diameter polyamide fibers and a 2 mm distance or 0.2 mm steel fibers spaced 5 mm apart, a peel strength of more than 1 kNm was already achieved with a compression pressure above 1 MPa.

Reducing the pressing pressure is especially important when connecting larger areas with portable presses, where the demands on the design, dimensions and weight of the presses are reduced.

Claims (1)

Method for reducing the content of volatile substances in glued joints of thermoplastic rubbers with rubber, polyamide textile and other polymeric materials, characterized in that a force of natural, artificial or metal fibers whose mutual distance is less than 10 mm is inserted between the glued surfaces.