摘要:
A process for preparing an urethane compound for medical instruments, characterized by reacting a hydroxyl compound (A) with an isocyanate compound (B) in the absence of a catalyst or in the presence of a reaction catalyst other than an organic tin compound to give an urethane compound (I). According to the process, the urethane compound showing high safety can be easily prepared, in particular, while molecular weight of the compound is controlled.
摘要:
An ocular lens material comprising a siloxane-containing polymer obtained by polymerizing a monomer mixture containing (A) a siloxane macromonomer having at least two active unsaturated groups and a number average molecular weight of 2,000 to 100,000; and (B) a vinyl ester of lower fatty acid as essential components. An ocular lens material comprising a polymer obtained by saponification of the siloxane-containing polymer. Processes for producing the ocular lens materials. The ocular lens materials are excellent not only in lipid-stain resistance, wettability and oxygen permeability, but also in flexibility, particularly, shape recovery at the same time.
摘要:
An ocular lens material made of a copolymer comprising, as main copolymerizable components, (A) a polysiloxane macromonomer having polymerizable groups bonded via one or more urethane bonds to the siloxane main chain and (B) an alkyl (meth)acrylamide, wherein the weight ratio of the polysiloxane macromonomer to the alkyl (meth)acrylamide is from 5/95 to 90/10.
摘要:
An ocular lens material made of a copolymer consisting essentially of (A) a polysiloxane macromonomer having polymerizable groups bonded by one or more urethane bonds to the siloxane main chain and (B) an alkyl (meth)acrylamide, wherein the weight ratio of the polysiloxane macromonomer to the alkyl (meth)acrylamide ranges from 10:90 to 90:10.
摘要:
A process for preparing an ocular lens with a urethane compound comprising the steps of a) preparing a urethane compound by reacting at least one hydroxyl compound and at least one isocyanate compound in the presence of an organic iron compound, b) removing the organic iron compound from the urethane compound obtained in the step a) c) mixing the urethane compound obtained in the step b) with at least one compound selected from the group consisting of another copolymerizable compound, a crosslinking agent, a UV absorbent, a dye, a polymerization initiator, a photosensitizer, and an organic solvent to obtain a mixture, and d) curing the mixture obtained in the step c) to prepare a lens.
摘要:
An ocular lens material comprising a polymer prepared by polymerizing a polymerizable component for an ocular lens, containing (A) 20 to 50% by weight of a silicon-containing alkyl acrylate, (B) 20 to 50% by weight of a polysiloxane macromonomer in which a polymerizable group bonds to a siloxane main chain through at least one urethane bond, (C) 10 to 50% by weight of at least one of hydroxyalkyl acrylates and at least one of hydroxyalkyl methacrylates, and (D) 0.01 to 10% by weight of a crosslinkable compound having at least two polymerizable groups, and a process for producing the same. The ocular lens material shows excellent stain resistance and excellent flexibility at the same time in addition to excellent transparency, and can be easily produced by the process.
摘要:
The present invention provides a process for purifying natural gas, comprising removing mercaptans from a natural gas stream by a combination of an amine-based separation unit and a selective oxidation unit to obtain a purified natural gas stream, wherein at least part of the mercaptans are converted into at least elemental sulphur in the selective oxidation unit by selective catalytic oxidation.
摘要:
A process is described for treating nitrogen-oxide containing gases at temperature in the range of 300-560.degree. C. in the presence of a cerium containing zeolite catalyst and an excess of an NH-containing compound such as ammonia or an aqueous urea solution as a reducing agent. Excess reducing agent is converted to nitrogen gas during the process. Selective catalytic reduction using ammonia water or an aqueous urea solution as a reducing agent is also described for converting nitrogen oxides in diesel exhaust gas and preventing oxidation of sulfur dioxide.
摘要:
A process for producing an ocular lens characterized by mixing a polymerizable component for an ocular lens with an organic solvent (I) capable of dissolving the polymerizable component, injecting the obtained mixture into a mold having the desired shape for an ocular lens and then, preparing a polymer by the polymerization reaction, immersing the polymer taken off from the mold in an aqueous organic solvent (II) having compatibility with the organic solvent (I), and then, hydrating the polymer, and an ocular lens produced by the process, which is, in particular, remarkably excellent in transparency.
摘要:
The present invention provides a process for purifying natural gas, comprising removing mercaptans from a natural gas stream by a combination of an amine-based separation unit and a selective oxidation unit to obtain a purified natural gas stream, wherein at least part of the mercaptans are converted into at least elemental sulphur in the selective oxidation unit by selective catalytic oxidation.