GB758777A - Improvements in method of making heat insulated waterproof footware - Google Patents

Abstract

758,777. Top boots. UNITED STATES RUBBER CO. June 28, 1954 [Aug. 4, 1953], No. 18866/54. Class 17 (2). [Also in Group V] Heat-insulated waterproof footwear is made by assembling a heat-insulating layer 14 of pre-blown closed-cell cured cellular rubber on a rigid last 11; applying to the layer 14 a waterproof protective layer 15 of uncured rubber; heating the two layers on the last in a fluid medium to cure the layer 15; and cooling the resulting article of footwear in the said fluid medium, the layer 14 being maintained at a substantially constant volume during the heating and cooling periods (to obviate expansion and resultant displacement or rupture thereof) by balancing the pressure of said medium with the variable pressure within the cells of the layer 14 during the heating and cooling periods. As described, the two layers are assembled on the last and adhered to each other, a partly or wholly cured one-piece sole-and-heel tread 27 is secured thereto, and the whole is placed in an autoclave 28. The layer 15 may be composed of smoked sheet GR-S rubber, SRF black, calcium carbonate, talc, zinc oxide, inhibitor of static atmospheric cracking, antioxidants (diarylamine-ketone-aldehyde reaction product, condensation product of acetone and aniline and a blend of phenyl #- naphthylamine, isopropoxy diphenylamine and diphenyl - p - phenylene - diamine), retarder or antiscorch (phthalic anhydride), accelerators (benzothiazyl disulphide and tetramethylthiuram monosulphide) and sulphur. The lining 12 may be composed of creamed latex, potassium hydroxide, potassium oleate, dispersing agent (soap), antioxidants (dialkyl phenyl sulphide and reaction product of acetone and phenyl - # - naphthylamine), accelerator (mercaptobenzothiazole), zinc oxide and sulphur.