Abstract: A hollow fiber membrane module and potting material can be used for chemical deaeration in a semiconductor production process, in printers, in a liquid crystal sealing process or in a chemical production process. A hollow fiber membrane module 1 includes, as potting material 2, an epoxy resin cured product in which the weight change per unit surface area of a potting material test piece after immersing the test piece in a chemical for 6 months at room temperature is within the range of −20 to +20 mg/cm2, and as housing 4, a polyolefin in which the weight change per unit surface area of a test piece after immersing the test piece in a chemical for 6 months at room temperature is within the range of −20 to +20 mg/cm2, and the total metal content is 300 ppm or less. The module has a long service life when used for chemical treatment without leakage.

Abstract: A hydrophilic polymer alloy which has a permanent hydrophilic nature, a sufficient mechanical strength and a high safety and which is suitable for the formation of hydrophilic porous membranes manufacturable by an industrially advantageous process can be prepared by blending an amorphous hydrophilic copolymer (X) containing 10 mole % or more of an ethylene unit, 10 to 60 mole % of a vinyl alcohol unit and 1 mole % or more of a vinyl acetate unit with a polyolefin (Y). Furthermore, this polymer alloy is also suitable for the formation of hydrophilic (porous) fibers having a sufficient mechanical strength and antistatic function.

Abstract: According to the present invention, spherical melamine resin particulates having a uniform particle size and crosslinked structure can be prepared by adding an acid catalyst to an aqueous solution containing at least 0.5 to less than 5% by weight of a melamine derivative which is polymerizable in the acid region, to adjust the pH of the aqueous solution to at least 4 to less than 5, and carrying out heat-treatment of the aqueous solution.The spherical melamine resin particulates thus obtained are useful as additives for coating compositions, pigments and other materials.