GB2175907A

GB2175907A - Fusion adhesives

Info

Publication number: GB2175907A
Application number: GB08407770A
Authority: GB
Inventors: Albers Guenter
Original assignee: Phoenix AG
Current assignee: Phoenix AG
Priority date: 1983-02-24
Filing date: 1984-03-26
Publication date: 1986-12-10
Also published as: GB8407770D0; GB2175907B

Abstract

A fusion adhesive for bonding moulded bodies and flat structures of EPDM together or to other materials comprises: a) SEBS-block copolymer rubber; b) 10-150 parts by weight per hundred parts of rubber, of aliphatic hydrocarbon resin; c) 50-300 parts by weight per hundred parts of rubber, of aromatic hydrocarbon or terpene resin; d) up to 1000 parts by weight per hundred parts of rubber, of bitumen having a RK softening point of 37/44-54/59. e

Description

SPECIFICATION Fusion adhesive for the connection of articles of EPDM The invention refers to a fusion adhesive for the connection of moulded bodies and flat structures of EPDM together or to other materials as they occur within the range of the art.

In the gluing of articles on a base of rubber types of every kind, in most cases solutions are employed having certain proportions of solids. But the application of such adhesives existing in solution causes difficulties if the articles exhibit large areas of adhesion, since the solvents being used must be eliminated from the article and the adhesive again. Therefore for such special duties fusion adhesives are also to a wide extent brought into use. These are free of solvent but must instead for the generation of an effective connection with a firm hold, be heated up to fairly high temperatures of e.g., 1500C, before they can be applied for gluing. The fusion adhesives existing on the market have indeed a wide possibility of application but cannot be applied in the case of articles on a base of EPDM.In the case of this synthetic rubber the values of the adhesive strength are inadequate and not very permanent. It has therefore already been proposed in the case of the connection of areas such as occur, for example, in the case of roof sealing strips, to provide that fibrous material protrudes at the surfaces, through which a mechanical clamping is effected. But the problem of connection at a seam cannot be solved in that way. Moreover fusion adhesives have also already come into application, which contain mixtures of EPDM, butadiene-styrene copolymer and bitumen. But gluing of that kind demands vulcanization and is therefore restricted to a few applications. Furthermore the costs in the case of adhesive connections of that kind are relatively high.

The problem of the invention is to create a fusion adhesive in which at least one of the areas which are to be connected consists of EPDM. An outstanding field of application is to be found in sealing strips and profiles employed in building and underground construction, which are employed for sealing purposes of every kind. In that case areas and regions at seams must be connected in one working step and with one adhesive.

The solution of this problem consists in accordance with the invention in that the fusion adhesive contains the following constituents: a) SEBS-block copolymer rubber; b) 10-150 parts by weight per hundred parts of rubber, of aliphatic hydrocarbon resin; c) 50-300 parts by weight per hundred part of rubber, of aromatic hydrocarbon resin; d) up to 1000 parts by weight per hundred parts of rubber, of bitumen having a RK softening point of 37/44-54/59.

In the case of the aforesaid SEBS-block copolymer it is a question of a polymer in which the central block consists of ethylene-butylene and the two endblocks consist of styrene. The ratio of styrene to olefin amounts to 30:70. The molar weight is of the order of magnitude of usual types of rubber. In the case of the aliphatic hydrocarbon resin it is a question of a byproduct from the processing of petroleum, which is obtained in the case of steam cracking. In the case the aromatic hydrocarbon resin it may be a question, for example, of an alphamethyl-styrenecopolymer. But a polyterpene resin may also be used.

The proportions specified for the two resins have to be matched to one another in order to guarantee a calibrated effect upon the SEBS. Through these resins the physical characteristics in the fusion adhesive and the state of the processing may be influenced.

In the case of the bitumens which come to be applied, certain limiting values in the softening have to be maintained, which are of significance in the processing of the fusion adhesive. In this connection bitumens of usual origin may be applied, but also bitumen which has been modified in its structure by oxidation.

In the case of the composition of the fusion adhesive in accordance with the aforesaid constituents it is indeed possible without the addition of bitumen to arrive at a permanent adhesive strength which is effective even from the beginning. But with regard to the fusion adhesives which in most cases are applied in large quantities, it is logical to provide a large proportion of bitumen. The expenditure on the gluing process can thereby be considerably reduced. It is also found that the admixture of bitumen leads to only a slighBtly lower peeling strength at higher temperature.

According to the invention it is moreover possible for the SEBS used to be substituted up to 20% by SEPS. In the case of the latter rubber it is likewise a question of a block copolymer with styrene groups lying at the ends. But the olefin central block consists on the other hand of ethylene and propylene. Through the addition of this SEPS the consistency can be modified and the minimum temperature for the heating process can be somewhat lowered so that the readiness of the fusion adhesive for gluing persists over a longer time.

According to the invention it is furthermore also possible to add to the fusion adhesive up to 150 parts by weight per hundred parts of rubber, of inorganic filler. For this purpose, e.g., silica and chalk come into consideration.

Even this additive does not lead to a disadvantageous influence upon the fusion adhesive effect, although through this additive the expense of the fusion adhesive may again be reduced.

The invention is made clear in the following example: SEBS 100 80 80 100 100 SEPS - 20 20 - - Aliphatic hydrocarbon resin 100 100 100 100 100 Aromatic hydrocarbon resin 50 50 50 50 50 Bitumen-RK 44/49 - - - 250 250 Mineral filler - - 50 - Peeling strength N per 1.5mm at room temp. 9.7 8.7 8.5 9.0 8.5 N at +80"C 4.4 3.2 3.3 3.8 1.0

Claims

1. A fusion adhesive for the connection of moulded bodies and flat structures of EPDM together or to other materials, in which the adhesive contains the following constituents: a) SEBS-block copolymer rubber; b) 10-150 parts by weight per hundred parts of rubber, of aliphatic hydrocarbon resin; c) 50-300 parts by weight per hundred parts of rubber, of aromatic hydrocarbon resin; d) up to 1000 parts by weight per hundred parts of rubber, of bitumen having a RK softening point of 37/44-54/59.

2. A fusion adhesive as claimed in claim 1 in which the SEBS is substituted up to 20% by SEPS.

3. A fusion adhesive as claimed in claims 1 and 2, which contains up to 150 parts by weight per hundred parts of rubber, of inorganic filler.