摘要:
A method of continuously fabricating a lens excellent in various optical characteristics and having no nonuniformity in the characteristics over a total of the lens and a lens fabricated by the method. A first step for forming thiourethane prepolymer and a second step for making thiourethane prepolymer react with at least one urethane forming monomer are carried out in an extruder or in a reactor having an extruding device at a succeeding step, extruded thermoplastic thiourethane-urethane copolymer for optical use is elongated in a sheet-like shape, a lens precursor is formed by punching out the copolymer elongated in a sheet-like shape and the lens precursor is pressed such that a predetermined curved face is provided at least on one face of the lens precursor.
摘要:
A process for making thermoplastic thiourethane-urethane copolymers for use in making optical products preferably comprising reacting an aliphatic diisocyanate with a dithiol under polymerization conditions to form a thiourethane prepolymer which is then reacted with a diisocyanate such as methylene bis(phenyl isocyanate) and a polyol such as a diaromatic containing diol such as ethoxylated Bisphenol A or an aliphatic isocyanate reactive monomer such as tricyclodecane dimethanol or 1,4-dimethanol cyclohexane to form the copolymer product. The polymers have a combination of high refractive index and high Abbe No. The polymers also have high impact strength, high hardness and Tg's above 100.degree. C. It is preferred to make the polymer in an extruder.
摘要:
A monomer composition characterized by being curable to form a resin suitable for optical products having a balanced refractive index and Abbe's number range and good tintability comprising a polyene monomer; and polyisocyanate, polyisothiocyanate, or an isocyanate monomer containing at least one isothiocyanate group; and a monomer having two or more active hydrogen groups such as polythiols, polyamines, and polyols. The invention also provides a special process for making the composition and for curing the composition to form a resin product.
摘要:
A monomer composition characterized by being curable to form a resin suitable for optical products having a balanced refractive index and Abbe's number range and good tintability comprising a polyene monomer; a polyisocyanate, polyisothiocyanate, or an isocyanate monomer containing at least one isothiocyanate group; and a monomer having two or more active hydrogen groups such as polythiols, polyamines, and polyols. The invention also provides a special process for making the composition and for curing the composition to form a resin product.
摘要:
An ultrasonic computed tomography tree or log scanner has a plurality of ultrasonic transceivers carried on a belt (102) sized to encircle a tree (100). The belt includes an apparatus for engaging is tightly around the tree (104). The transceivers are strapped around the tree, and their mutual relative distances are known. Electronic circuitry energizes the transmitters in a known sequence. The signals received at each of the receivers are also collected and analyzed. Computed tomographic techniques analyze the time of arrival of the acoustic pulse that is first to arrive at each receiver. A signal processor generates a two-dimensional image of a slice of the tree (110) at the locus of the belt.
摘要:
A polyurethane-urea is prepared by reacting a mixture of a p-phenylene diisocyanate terminated urethane prepolymer, at least one plasticizer, and alkylated 4,4′-methylenedianiline chain extender.
摘要:
Polyurethane prepolymers with reduced amount of unreacted monomeric hexamethylene 1,6-diisocyanate (HDI) are provided. Also provided are polyurethane elastomers obtained by mixing the polyurethane prepolymers having reduced amount of unreacted monomeric HDI with amine and/or hydroxy chain extenders and durable, resilient, colorfast golf ball covers obtained therefrom. Rolls, wheels and tires obtained from the polyurethane elastomers are also provided.