Abstract: The present invention relates to a photopolymerizable composition comprising a polymerizable, polyethylenically unsaturated compound, benzil and/or fluorenone, a specific biphenyl ketone such as para-phenyl benzophenone, and a reducing agent such as a tertiary amine. The present composition permits rapid and complete curing. Moreover, in the photopolymerization of compounds sensitive to air inhibition non-tacky surfaces are obtained. The effect observed is based on a synergism between the present photoinitiators. The advantages of the invention are most manifest in curing relatively thick layers of materials.

Abstract: The present invention relates to a photopolymerizable composition comprising a polymerizable, polyethylenically unsaturated compound, benzil and/or fluorenone, a specific biphenyl ketone such as para-phenyl benzophenone, and a reducing agent such as a tertiary amine. The present composition permits rapid and complete curing. Moreover, in the photopolymerization of compounds sensitive to air inhibition non-tacky surfaces are obtained. The effect observed is based on a synergism between the present photoinitiators. The advantages of the invention are most manifest in curing relatively thick layers of materials.

Abstract: The present invention relates to a photopolymerizable composition comprising a polymerizable, polyethylenically unsaturated compound, benzil and/or fluorenone, a specific biphenyl ketone such as para-phenyl benzophenone, and a reducing agent such as a tertiary amine. The present composition permits rapid and complete curing. Moreover, in the photopolymerization of compounds sensitive to air inhibition non-tacky surfaces are obtained. The effect observed is based on a synergism between the present photoinitiators. The advantages of the invention are most manifest in curing relatively thick layers of materials.

Abstract: A process is disclosed for the preparation of polymers and copolymers of yl choride, which comprises polymerizing vinyl chloride or copolymerizing vinyl chloride and monomers copolymerizable therewith in the presence of a peroxide having the general formula ##SPC1##Wherein R represents an alkyl- or an alkoxy-group having from 1-6 carbon atoms as an initiator. The initiator is used in an amount of 0.01 to 1.0% by weight, calculated on the monomer or monomer mixture. The foregoing peroxide may be used in combination with another structurally similar peroxide or with other peroxides also capable of polymerizing or copolymerizing vinyl chloride in an amount of 0.01 to 0.1% by weight, calculated on the monomer or monomer mixture.

Abstract: A polymer initiator composition and method for its production are provided, the composition being non-separating and stable and including a substantial amount of a dibenzoyl peroxide and an effective amount of a hydrophobic alkyl group-containing silica in an amount sufficient to prevent the composition from physically separating into its components.