摘要:
A process for coating a polypropylene or polyethylene surface with a maleic acid-grafted polypropylene or polyethylene copolymer, and stretching the surface to increase permeability without damaging the coated surface. In this process, a dope containing the graft copolymer is applied to the polypropylene or polyethylene surface, e.g. by dip coating, at a temperature high enough to keep the copolymer solvated in the dope solvent; the surface is then dried. The permeability of the surface is improved by stretching the surface at least about 50% beyond its original area or length such that when the stretching force is released a residual strain of less than about 11% exists. The stretching operation may be done simultaneously with or subsequent to the coating operation.
摘要:
The present invention relates to a biasing arrangement for use with a filter element having a longitudinal bore therethrough. The biasing arrangement includes a spring element having first and second ends and being comprised of a plastic material. The spring element is deformable by pressure applied in the direction generally along an axis extending between the first and second ends. A sealing disk is adapted to seal an end of the longitudinal bore of the filter element. The sealing disk is also comprised of a plastic material and is positively secured to an end of the spring element. According to a further aspect of the present invention, the sealing disk is positively secured to an end of the filter element to define an integral filter unit. In the preferred embodiment, the spring element, the sealing disk, and the filter element are all comprised of compatible plastic materials. In accordance with a further aspect of the present invention, the spring element has a non-linear load/deflection characteristic such that a large force is obtained during initial deflection followed by a substantially constant force upon further deflection.
摘要:
A flame-resistant polybutylene terephthalate molding composition has vastly improved fatigue strength and improved melt flow by incorporating therein a halogenated epoxy flame retardant represented by the general formula: ##STR1## wherein an n is the degree of polymerization and the halogenated epoxy resin has a molecular weight of at least about 20,000 to 40,000; X is a chlorine or bromine atom, and i is an integer of from 1-4.
摘要:
The tensile modulus of fibers made from liquid crystalline polymers comprising 6-oxy-2-naphthoate and 4-oxybenzoate monomer units that have been heat treated can be increased by applying and then releasing a stress at room temperature in the range of about 25% to about 90% of the tensile strength of the heat treated fiber to yield a "pre-stressed" fiber.