Patent GB-685090-A (GB)
Title: A process for curing halosulphonated hydrocarbon polymers
IPC: C08K3/00
Filed: 1950-12-06
Abstract: The curing of halosulphonated hydrocarbon polymers is characterized in that during compounding or other pre-treatment prior to curing, the moisture content in the mixture is less than 0.5 per cent by weight, or the quantity of hydrolysing agent in the mixture is equivalent to less than 0.75 per cent by weight of water, thus eliminating scorching during the working.  The preferred polymer is chlorsulphonated polythene; others specified are chlorsulphonated polyisobutylene, asphalt, Fischer - Tropsch hydrocarbons, and interpolymers of butadienestyrene, butadiene - toluene and butadiene - xylene.  The presence of moisture or hydrolysing agents being essential for a "tight" cure, the polymer and compounding agents are dried, and mixed at temperatures of 50-150 DEG  C., and moisture or hydrolysing agent is then added to give a content of 0.75 to 4.5 per cent and curing is conducted at 90-150 DEG  C. for from 0.1 to 20 hours.  Suitable hydrolysing agents are hydrated metal salts and oxides, e.g. hydrated-aluminium sulphate, -calcium sulphate, -calcium chloride and -calcium silicate; organic compounds containing hydroxyl groups, e.g. ethylene and other glycols, pentaerythritol, sorbitol, sugars, polyvinyl alcohol, glycerols and mono-, di- and tri-ethanol amines; and polyvalent metal hydroxides.  The moisture content may be brought down to the required level for working by the use of a dehydrating agent, e.g. calcium oxide and chloride, formate esters, organic acid anhydrides and halides, silica gel, alumina, calcium formate, sodium aluminate and sulphur trioxide, and adsorbing agents such as carbon black.  Anhydrous salts which take up moisture and release it at the higher temperature of curing, e.g. calcium chloride and sulphate, are especially useful.  Specification 591,058 is referred to.ALSO:The curing of halosulphonated rubber (including hydrogenated and isomerised rubber) is characterised in that during compounding or other pre-treatment prior to curing, the moisture content in the mixture is less than 0.5 per cent by weight, or the quantity of hydrolysing agent in the mixture is equivalent to less than 0.75 per cent by weight of water, thus eliminating scorching during the working.  The presence of moisture or hydrolysing agent being essential for a "tight" cure, the ingredients are dried, and mixed at temperatures of 50 DEG -150 DEG  C., and moisture or hydrolysing agent is then added to give a content of 0.75 to 4.5 per cent, and curing is conducted at 90-150 DEG  C. for from 0.1 to 20 hours.  Suitable hydrolysing agents are hydrated metal salts and oxides, e.g. hydrated-aluminium sulphate, -calcium sulphate, -calcium chloride and -calcium silicate; organic compounds containing hydroxyl groups, e.g. ethylene and other glycols, pentaerythritol, sorbitol, sugars, polyvinyl alcohol, glycerols and monodi- and tri-ethanol amines; and polyvalent metal hydroxides.  The moisture content in the working may be brought down to the required level by the use of a dehydrating agent, e.g. calcium oxide and chloride, formate esters, organic acid anhydrides and halides, silica gel, alumina, calcium formate, sodium aluminate and sulphur trioxide, and adsorbing agents such as carbon black.  Anhydrous salts which take up moisture and release it at the higher temperature of curing, e.g. calcium chloride and sulphate, are especially useful.  The halosulphonated rubbers may be prepared by treating the rubber with a gaseous mixture of sulphur dioxide and chlorine or other halogen, if desired with illumination, or in the presence of an azo or other catalyst.  Specification 591,058, [Group IV], is referred to.