Mitsui Petrochemical Industries, Ltd.

Takao Ohno

Hitoshi Mantoku

Masanori Motooka

Mayumi Kawasaki

Tetsuya Miyazaki

Syuji Minami

Hidekuni Oda

Yoshihisa Ushida

Hirokazu Kajiura

Nobuki Hirai

Yozo Yamamoto

Disclosed is a highly light-transmitting dust protective film composed of at least one member selected from the group consisting of transparent gels of oxides, hydroxides, organic group-containing oxides and organic group-containing hydroxides of polyvalent metals, formed by the sol-gel process.

Highly light-transmitting dust protective film, and dust protective

Highly light-transmitting dust protective film, process for preparation

Ferroelectric ceramics represented by xPbTiO.sub.3 -yPbZrO.sub.3 -zPb(Mg.sub.1/3 Nb.sub.2/3)O.sub.3 -mSrTiO.sub.3 -nSnO.sub.2 -pZnO-qBi.sub.2 O.sub.3 -rX wherein x,y,z,m,n,p,q and r represent amounts by mole, respectively, with the proviso that x+y+z being 1, Z is at least one oxide selected from the group consisting of Dy.sub.2 O.sub.3, Ta.sub.2 O.sub.5, and Y.sub.2 O.sub.3, and wherein x is from 0.25 to 0.50, y is from 0.05 to 0.70, z is from 0.05 to 0.70, m is from 0 to 0.10, n is from 0 to 0.04, p is from 0 to 0.04, q is from 0 to 0.02 and r is from 0.005 to 0.02. The disclosed ferroelectric ceramics have increased relative dielectric constant and/or electromechanical coupling factor, and are suitable for use as actuators.

Ferroelectric ceramics

Stretched articles of ultrahigh-molecular-weight polyethylene are prepared by melt-kneading a mixture of ultrahigh-molecular-weight polyethylene with a paraffinic wax having a melting point of 40.degree. to 120.degree. C. and a weight average molecular weight of at least 230 but less than 2000 in a screw extruder while maintaining the temperature of the mixture at 180.degree. to 280.degree. C. The molten mixture is melt-extruded through a die at a temperature of 180.degree. to 300.degree. C. under a draft condition of a draft ratio of less than 2 or in the absence of a draft and the resulting unstretched extrudate is cooled to solidify it. The unstretched solidified extrudate is than subjected to a stretching treatment in a heated liquid medium which is a solvent for the paraffinic wax at a temperature of 60.degree. to 140.degree. C. at a particular stretch ratio. Stretch shaped articles of ultrahigh-molecular-weight polyethylene having high tensile strength and modulus of elasticity are produced uniformly and reproducibly. The stretched shaped articles are substantially free from stretching uneveness. Examples of the paraffinic wax include n-alkanes having at least 22 carbon atoms.

Process for producing stretched articles of ultrahigh-molecular-weight

Stretched articles of ultrahigh-molecular-weight polyethylene are prepared by melt-kneading a mixture of ultrahigh-molecular-weight polyethylene with a paraffinic wax having a melting point of 40.degree. to 120.degree. C. and a weight average molecular weight of at least 230 but less than 2000 in a screw extruder while maintaining the temperature of the mixture at 180.degree. to 280.degree. C. The molten mixture is melt-extruded through a die at a temperature of 180.degree. to 300.degree. C. and the resulting unstretched extrudate is cooled to solidify it. The unstretched solidified extrudate is then subjected to a stretching treatment at a temperature of 60.degree. to 140.degree. C. at a particular stretch ratio. Stretch shaped articles of ultrahigh-molecular-weight polyethylene having high tensile strength and modulus of elasticity are produced uniformly and reproducibly. The stretched shaped articles are substantially free from stretching uneveness. Examples of the paraffinic wax include n-alkanes having at least 22 carbon atoms.

A random copolymer consisting essentially of 40 to 90 mole% of propylene and 60 to 10 mole% of 1-butene, and having (A) a boiling n-heptane-insoluble content of not more than 5% by weight based on the weight of the copolymer, (B) a boiling methyl acetate-soluble content of not more than 2% by weight based on the weight of the copolymer, (C) a melting point, determined by differential thermal analysis, of 40 to 140.degree. C., (D) an intrinsic viscosity, determined in decalin at 135.degree. C., of 0.5 to 6 dl/g, (E) an elongation at break, measured by JIS K6301, of at least 300%, (F) a tensile strength at break, measured by JIS K6301, of at least 50 kg/cm.sup.2, and (G) a haze, measured by JIS K6714, of not more than 40%. The above copolymer has superior properties for production of various kinds of melt-shaped articles such as films, sheets, vessels and tubes, and can be obtained by copolymerizing propylene and 1-butene in the presence of a catalyst prepared from a solid complex containing magnesium, titanium and halogen, an organometal compound of a metal of Groups I to III of the periodic table, and an electron donor.

Growing community of inventors

Ohtake, Japan

Takao Ohno