Abstract: An optical filter for a liquid crystal display device, consisting of a polymer film which has two types of layers having different refractive index which exist alternately in a laminated state, in which a difference of refractive index between two types of layers is in the range between 0.01 and 0.1, an average thickness of each layer is at least 0.8 .mu.m and less than 2 .mu.m, and a thickness of the polymer film is in the range between 10 to 300 .mu.m, which filter can widen an angle of view of the liquid crystal display is greatly without the improvement of the liquid crystal cell, change of an addressing system or modification of the liquid crystal itself.

Abstract: A composite-material structure of T-shaped cross section has a horizontal plate and an integral vertical web. The vertical web is formed between opposite forming faces of die members, and the horizontal plate is formed between the die members and a horizontal pressing plate positioned above or below the die members. In order to urge the die members against each other for forming, wedges are provided. The die members, pressing plate and wedges are placed between a lower stationary part and an upper movable part of a pressing machine. When the movable part descends towards the stationary part, the wedges exert forces to the die members to urge the members toward each other due to a wedge action, and the pressing plate is vertically urged against the die members.

Abstract: Rigid polyurethane foams are obtained by reacting an isocyanate-reactive component containing at least two isocyanate-reactive hydrogen atoms, having a molecular weight of from 32 to 10,000 or a mixture thereof, with a polyisocyanate composition comprising(a) 30 to 70 pbw of polymethylene polyphenyl polyisocyanate with an iscocyanate content of from 29 to 32%,(b) 30 to 70 pbw of a compound having 30 to 42% by weight isocyanate content obtained by reacting 2,4- and/or 2,6-tolylene diisocyanate with an active hydrogen containing compound, thereafter initiating a reaction in the presence of trimerization catalyst, if necessary diluted with 2,4- and/or 2,6-tolylene diisocyanate,(c) 0 to 30 pbw of other isocyanate compounds in the presence of water and/or organic blowing agents, catalysts and surfactants.

Abstract: A novel magnetic recording medium consisting of a base material, magnetic particles and a specific polyurethane-based binder containing incorporated sulphonate groups, a process for preparing such a magnetic recording medium which comprises coating a base material with a coating material comprising (i) an organic solvent, (ii) a polyurethane binder containing chemically incorporated sulphonate groups and (iii) magnetic particles and the most preferred binder composition therefor comprising a hexandiol-(1,6)-polycarbonate-based polyurethane.