The present invention relates to a catalyst system for the production of polyurethane comprising catalysts for polyurethane formation and sterically hindered carbodiimides, which system is capable of lessening the "fogging" problem in the production of polyurethane materials, without impairing in particular the aging properties of the polyurethane materials thus produced.

A photoelectric converting device is provided with a control electrode area consisting of a semiconductor of a first conductive type, first and second main electrode areas consisting of a semiconductor of a second conductive type different from the first conductive type, and a drive line capacitively coupled to the control electrode area for controlling the potential thereof, and adapted to read a signal from the first main electrode area, by the potential control of the control electrode area, based on a charge generated by an incident light energy and accumulated in the control electrode area. The potentials of the first main electrode areas and of the drive line are elevated during the light signal accumulating operation to elevate the potential of the control electrode area, thereby rendering the potential difference between the control electrode area and the second main electrode area smaller than at the end of charge resetting of the control electrode area.

The invention provides co-solvents for preparing clear solutions of a biocidal agent known as 10, 10'-oxybisphenoxarsine (OBPA). The clear solutions are stable over a relatively broad range of temperatures and have very low Volatile Organic Carbon (VOC) content. They can be included in master batches for the manufacture of plastic materials, such as flexible PVC. The co-solvents of this invention have very low VOC values, do not have troublesome odors, do not cause significant irritation during the high temperature plastic manufacturing process, and are miscible in a range of useful concentrations with plasticizers presently employed by plastics manufacturers. The use of castor oil and/or modified castor oils such as glyceryl ricinoleate, dehydrated castor oil, and certain alkoxylated castor oils as a co-solvent to increase the dissolvable concentration of OBPA, alone or in solution with a plasticizer, was not known or expected.

The invention provides a process for preparing an overvoltage protection material comprising: (i) preparing a mixture comprising a polymer binder precursor and a conductive material; and (ii) heating the mixture to cause reaction of the polymer binder precursor and generate a polymer matrix having conductive material dispersed therein, wherein the polymer binder precursor is chosen such that substantially no solvent is generated during the reaction.