Thermoset resin impregnated web and process of making
AssigneeW. R. Grace & Co.
InventorCharles B. Moore
Life of this patent
Estimating the term…
Abstract
Battery separators, filters and other porous semi-rigid products are provided by a thermoset resin impregnated fibrous web containing cellulosic fiber, synthetic wood pulp, paper making staple long fiber and thermoset resin. The temperature for thermosetting can exceed the Vicat softening and even the melting temperature of the synthetic pulp without the loss of the flexibilizing effect of the synthetic pulp. By extension the teaching reaches to non-fibrous and non-porous materials. A process is also revealed.
Claims27
A fibrous web containing thermoset resin, said web comprising about 15 to about 95% by fiber weight of cellulosic fiber;
- about 5 to about 85% by fiber weight of thermoplastic synthetic pulp fiber;
- and at least about 5% by weight of thermoset resin based on the weight of the fiber, said thermoset resin having been at least partially cured at a temperature above the melting or Vicat softening or shrinking by more than 5% temperature of said thermoplastic synthetic pulp and thereafter said web being fracture resistant as determined by cutting said web into strips 15 cm wide by 15 cm long and bending said strips over a 2.5 cm diameter mandrel to the extent of engaging 1/2 of the mandrel circumference without fracture in repetitions of at least 90 out of 100 repetitions using a separate strip for each repetition, said at least partial curing of said thermoset resin in the same quantity in an all cellulosic fiber web of the same weight and thickness resulting in fracture in at least 50 out of 100 repetitions when subjected to said determination.
A fibrous web containing thermoset resin, said web comprising about 25% to about 95% by fiber weight cellulosic fiber, about 5 to about 75% by fiber weight synthetic pulp fiber and about 5 to about 100% by weight thermoset resin based on the weight of the fiber.
A composite comprising a thermosettable resin and a thermoplastic member, said composite being formed by a process comprising assembling said thermosettable resin and said member and thereafter thermosetting said resin by subjecting said composite to a temperature higher than the melting point, or Vicat softening point of said thermoplastic member.
A battery separator comprising a fibrous web containing thermoset resin, said web comprising about 15% to about 95% by fiber weight cellulosic fiber, about 5 to about 85% by fiber weight thermoplastic synthetic pulp fiber and at least about 5% by weight thermoset resin based on the weight of the fiber.
A process of forming a thermoset resin impregnated fibrous web comprising forming an aqueous slurry comprising about 3 to about 95% by fiber weight of cellulosic fiber and about 5 to about 97% by fiber weight of thermoplastic polymeric synthetic pulp fiber, dewatering said slurry and forming a web, impregnating said web with a thermosettable resin in an amount of at least about 2% by weight based on the weight of the fiber, and thereafter heating said thermosettable resin above the melting or Vicat softening or shinking by more than 5% temperature of said thermoplastic synthetic pulp fiber until said resin is at least partially cured.
A process of forming a thermoset resin impregnated fibrous web comprising
- (1) forming an aqueous slurry comprising about 25 to about 95% by fiber weight cellulosic fiber and about 5 to about 75% by fiber weight synthetic pulp fiber consisting essentially of polyolefin and having at least a melting point or a softening point or a shrinking by more than 5% point below 150.degree. C.;
- (2) after the formation of said aqueous slurry adding a wet strength resin to said aqueous slurry in an amount of about 0.1 to about 2% by weight based on the weight of the fiber and adding long fiber to said aqueous slurry in an amount of about 1 to about 15% by fiber weight;
- (3) dewatering said slurry and forming a web;
- (4) impregnating said web with thermosettable resin in an amount of at least 5% by weight based on the weight of the fiber;
- and
- (5) thereafter heating said thermosettable resin impregnate to a temperature in excess of about 80.degree. C., and at least partially curing said resin.
The method of preparing a thermoset resin--thermoplastic member composite comprising thermosetting said resin while it is combined with said thermoplastic member at a temperature higher than the melting point or Vicat softening point of said member.
Dependencies are inferred from the claim text.