Bridgestone Corporation

Kuniaki Yasunaga

Shigeru Ueno

Toru Okuyama

Yasuo Kamimura

An ink retainer is comprised of a flexible polyurethane foam which is prepared by reacting a polyether polyol with a polyisocyanate. The polyol includes at least 20% by weight based on the total weight of the polyol of a polymeric polyol having styrene and/or acrylonitrile grafted thereto. The foam contains at least 20 cells/inch. The foam is inserted in a container at a compression ratio by volume of 1/2 to 1/10 when the cell number is 20 to 50 cells/inch and 1/1 to 1/5 when the cell number is more than 50 cells/inch. The foam is resistant against attack from ink and ensures stable constant supply of ink.

Ink retainer

A method for producing antistatic polyurethane resins according to the present invention comprises a reaction of a compound having at least two active hydrogen atoms with an organic isocyanate in the presence of at least one kind of complex compounds represented by a general formula [Me(ClO.sub.4).sub.n ].sub.x [R(OH).sub.y ].sub.z and being liquid at room temperature, wherein Me is an element belonging to Group I or II in the periodic table; n is a number of 1-2; x is a number of 1-5; y is a number of 1-3; z is a number of 1-6; and R is a residual group other than hydroxyl group in a polyhydric alcohol or its derivative. Me of said complex compounds is preferably Li, Na, K, Ca or Ba. As antistatic agents are liquid at room temperature in the present invention, they can be formulated uniformly within raw materials of polyurethane resins. By virtue thereof, the antistatic effect is exhibited homogeneously and so highly.

Method for producing antistatic polyurethane resin

The present invention provides a process for producing an antibacterial flexible polyurethane foam containing an antibacterial agent dispersed therein from a foaming mixture composed of polyols, organic isocyanates, catalysts, and blowing agents. The process is characterized in that the antibacterial agent is added to the foaming mixture and the catalyst is an organic amine which is used alone or in combination with a tin compound. In the latter case, the tin compound is a tetravalent tin compound or a divalent tin compound which is used in an amount less than 1 part by weight for 1 part by weight of the antibacterial agent. The antibacterial flexible polyurethane foam retains the antibacterial action for a long time and is safe because it contains an inorganic antibacterial agent dispersed therein which does not yield resistant bacteria.

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Yokohama, Japan

Kuniaki Yasunaga