DE1720082B2 - Solvent mixture - Google Patents

Description

The invention relates to mixtures of chlorinated aliphatic hydrocarbons for dissolving Rubber-resin mixtures, which are not flammable and which have determinable evaporation rates exhibit.

The rubbers considered here include natural rubber, regenerated rubber, synthetic rubbers and rubber conversion products, such as chlorinated rubber, cyclized rubber and rubber hydrochloride. In Dissolved in solvents, they are used as adhesives. The manufacture of the basic rubber compounds and the incorporation of resins has a significant impact on the properties of the adhesive the end. When other considerations permitted, solvents became economical selected. The cheapest and most economical are aliphatic hydrocarbons, which are used for rubber, cyclized rubber and hydrocarbon polymers (butadiene-styrene rubber, butyl rubber and polyisobutylene) are suitable. The aromatic hydrocarbon solvents that generally for chlorinated rubber, chloroprene poly-

In the respective cylindrical housing, (1) mers and butadiene-acrylonitrile copolymers with little Acrylonitrile content used are benzene and toluene. Ketones, nitro paraffins, chlorinated hydrocarbons or esters are used to dissolve butadiene-acrylonitrile copolymers with higher acrylonitrile content required. The choice of resins for use with these adhesive bases is discussed in generally determined by solubility considerations. E, ster (e.g. phthalates) are suitable along with nitrile rubber, while hydrocarbon resins or those with a low content more suitable for butadiene-styrene rubber, butyl rubber and polyisobutylene on polar groups are. Chlorinated resins can be used together with chlorinated rubber. Typical resins, which are added to the rubber and the solvent to improve the adhesiveness, are generally based on terpene polymers, the hydrogenated coumarone-indene resins, phenol-aldehyde resins and the acetylene-p-tert-butyl-phenol resins. It is easy to see, however, that the most commonly used solvents for adhesives Rubber based the liquid petroleum hydrocarbons with low molecular weight, the aromatic ones Hydrocarbons, such as benzene and toluene, and the lower aliphatic ketones, such as methyl ethyl ketone, are. With a few exceptions, the solvents used during the past few years have been flammable and in some cases have an unpleasant odor. Also, many have solvents poor evaporation rates and limited solvency for certain rubbery ones Elastomers used as the basis for rubber adhesives.

The invention relates to the division of a non-flammable solvent, which is particularly suitable for Rubber based adhesives is suitable. Another object of the invention is to produce a solvent for rubber-based adhesives, which, in addition to the aforementioned advantages, have higher concentrations on rubber and resin can dissolve than the currently usual solvents and those within certain Limits of determinable evaporation

ao have speeds.

The solvent mixture according to the invention of chlorinated, aliphatic hydrocarbons for Dissolving rubber-resin mixtures is characterized in that they consist of 20 to 70 volume percentages.

»5 cent methylene chloride and at least 2 of the following Components consists of: 0 to 40 percent by volume trichlorethylene, 0 to 70 percent by volume 1,2-dichloroethylene, 0 to 25 volume percent ethylene chloride and 0 to 40 volume percent methyl chloroform.

Three- and four-component systems are preferred. Of these hydrocarbons are two namely 1,2-dichloroethylene and ethylene dichloride, according to Underwriters Laboratory Ratings Flammable. If neither trichlorethylene nor methyl chloroform are used, the amount of 1,2-dichloroethylene used is greater than 1 percent by volume and preferably greater than 10 percent by volume. Compositions according to the invention which are found to be useful proven are the following:

Methylene chloride.

1,2-dichloroethylene

Trichlorethylene ...

Ethylene dichloride ..

Methyl chloroform

Composition by volume

A I B I C I D

20th
70
10

40

20th

15 25

30 50 20

The preferred solvent compositions from the standpoint of non-flammability and solvency are mixtures of 20 to 40% methylene

chloride, 50 to 70% 1,2-dichloroethylene and 10 to 20% Trichlorethylene as a three component solvent and from 30 to 70% methylene chloride, 5 to 20% ethylene chloride, 10 to 30% trichlorethylene and 15 to 35% methyl chloroform as a four-component solution

medium, whereby 1,2-dichloroethylene is the ethylene dichloride or which can replace methyl chloroform. The following examples illustrate the invention:

example 1

Various amounts of a terpene phenolic resin were added to 100 ml of one of the following table listed solvent mixture dissolved. to

I 720 082

A rubber cut into small pieces was added to each resin-solvent solution. The various rubbers used were chloroprene rubber, butadiene rubber-acrylonitrile and butadiene rubber-styrene. The relative amounts of aa rubber and resin used were 2 parts by weight of rubber per part of resin. Three different concentrations of rubber-resin compositions were also used, namely 15 g rubber-resin solids (10 g rubber and 5 g resin), 30 g rubber-resin solids (20 g rubber and 10 g resin) and 60 g Rubber-resin solids (40 g rubber and 20 g resin). After the resin was dissolved in the solvent, the resulting mixture was poured into a resin-lined tin can with a resin-coated lid. The necessary amount of rubber in small pieces was added, a stainless steel roller bar was placed in the tin can, and the lid was pressed tightly to form a liquid-tight seal. A plurality of tin cans similarly made and differing only in the kind and amount of rubber-resin solids were packed in a cylindrical cardboard container, and the container thus packed was placed on a rotary roller mill. The mill was operated continuously overnight. In the morning, the metal containers were removed from the cylinder and the contents of each metal container were placed in a clean 118 cm ² bottle with a tin-lined screw cap. The material from each sheet metal container was examined during and after this transfer for any signs of composition heterogeneity. Shortly after the pouring was completed, the viscosity of the samples, which showed no visible heterogeneity, was measured with a Brookfidd viscometer. The viscosity measurements were all carried out on the same day on which the pouring was carried out from the metal containers. The results of the observations and those from the implementation of the

ao above measures determined data are with the following listed:

Table I.

solvent
Volume percentage Rubber har
Art τ.
100 ml viscosity
Centipoises. Remarks 1. 70% CHCl = CHCl ¹ )
20% CH ₂ Cl ₂
10% CHCl = CCl ₂ Polychloroprene 15th
30th
60 340
5 950 it became a heterogeneous phase
observed Butadiene acrylonitrile
rubber 15th
30th
60 294
3 950
12 080 Butadiene styrene
rubber 15th
30th
60 76
700
10 040 2. 40% CH ₂ Cl ₂
25% CH ₃ -CCl ₃
20% CHCl = CCl ₂
15% CH ₂ Cl-CH ₂ Cl Polychloroprene
Butadiene acrylonitrile
rubber 15th
30th
60
15th
30th
60 446
6 750
349
5,000 it became a heterogeneous phase
observed
it became a heterogeneous phase
observed Butadiene styrene
rubber 15th
30th
60 80
1050
13 320 3. 50% CHCl = CHCl
30% CH ₂ Cl ₂
20% CHCl = CCl ₂ Polychloroprene 15th
30th
60 313
5,970 it became a heterogeneous phase
observed

') 40% ice, 60% trans.

Table Il

To determine the solubility of rubber alone in the solvent mixture according to the invention the rubbers given below were converted into those according to the invention also given below Solvent mixtures dissolved, the stated viscosity values being measured.

50 g rubber, Solvent- viscosity dissolved in 100 ml mixture the solution solvent (in percent by volume) in cP Lower molecular weight Butadiene acrylonitrile rubber Mixture A 1400 the same Mixture B 2300 Butadiene acrylonitrile Rubber with mitt ler molecular size weight Mixture A 3500 the same Mixture B 3600 High molecular weight Butadiene acrylonitrile rubber M'schung A 5200 desg !. Mixture B 8100

Mixture A = methylene chloride 40 percent by volume trichlorethylene 20 percent by volume ethylene dichloride 15 percent by volume methylchloroform 25 percent by volume Mixture B = methylene chloride 30 percent by volume
Ethylene dichloride 50 percent by volume
Trichlorethylene 20 percent by volume

The rate of evaporation of the solvent compositions according to the invention is around about 2.4 to 3.0 compared to ethyl ether than 1 (according to the National Association of Mutual Casualty Companies Handbook of Organic Industrial Solvents,

2nd Edition). The evaporation rates of methyl ethyl ketone are 2.7 and that of toluene 4.5 on the same scale.

The solvent compositions according to the invention are designated as non-flammable on the basis of the test data determined by flammability tests. Methyl ethyl ketone, toluene and hexane, on the other hand, are flammable materials, such as two of the individual components of the composition according to the invention, namely 1,2-dichloroethylene and ethylene chloride. It is therefore surprising that the compositions according to the invention, which contain more than 50 percent by volume of one or both of the latter constituents, are not flammable.

Claims (1)

Claim: Solvent mixture of chlorinated, aliphatic hydrocarbons to dissolve Rubber-resin mixtures, characterized in that they are 20 to 70 percent by volume consists of methylene chloride and at least two of the following components: 0 to 40 percent by volume Trichlorethylene, 0 to 70 percent by volume 1,2-dichloroethyleri, 0 to 25 percent by volume ethylene chloride and 0 to 40 volume percent methyl chloroform.