摘要:
Siloxanes are polymerized by equilibration, condensation and/or ring-opening polymerization using a phosphazene base catalyst. A linear phosphazene base catalyst of the general formula wherein R denotes a C1-10 hydrocarbon or wherein two R groups on one N atom form with the N atom a heterocyclic group, X denotes an anion and n is from 1 to 10 is prepared by reacting a linear phosphonitrile halide compound with a secondary amine or a salt of a secondary amine or a metal amide thereof to form an aminated phosphazene material, followed by an ion exchange reaction replacing the anion with a nucleophile.
摘要:
A polymerization process comprising mixing a siloxane having silicon-bonded groups R′ and a cyclic or linear siloxane having no silicon-bonded groups R′ with a phosphazene base catalyst in the presence of water and allowing the siloxane having silicon-bonded groups R′ to condense and the cyclic or linear siloxane having no silicon-bonded R′ groups to polymerize by equilibration.
摘要:
A composition is capable of curing via condensation reaction. The composition uses a new condensation reaction catalyst. The new condensation reaction catalyst is used to replace conventional tin catalysts. The composition can react to form a gum, gel, rubber, or resin.
摘要:
A polymerization process comprising mixing siloxane polymers with organosilicon compounds having at least one silicon-bonded group RN, which is a substituent comprising at least one amine group, and with a phosphazene base catalyst and allowing the siloxanes and organosilicon compounds to polymerize to form amino-functional polyorganosiloxane polymers is claimed. Preferably the phosphazene base is selected from the following formulae: ((R12N)3P═N—)x(R12N)3−xP═NR2; {((R12N)3P═N—)x(R12N)3−xP—N(H)R2}+{A−} {((R12N)3P═N—)y(R12N)4−yP}+{A}− or {(R12N)3P═N—(P(NR12)2═N)n—P+(NR12)3}{A−} in which R1 is hydrogen or an optionally substituted hydrocarbon group, or in which two R1 groups bonded to the same N atom may be linked to complete a heterocyclic ring, R2 is hydrogen or an optionally substituted hydrocarbon group, x is 1, 2 or 3; y is 1, 2, 3 or 4, n is an integer with a value of from 1 to 10 and A is an anion.
摘要:
A polymerization process comprising mixing siloxanes having silicon-bonded groups R′ with ionic phosphazene base catalysts and allowing condensation via reaction of Si—R′ groups with the formation of a Si—O—Si linkage, R′ denoting a hydroxyl group or a hydrocarbonoxy group having up to 8 carbon atoms is claimed. The catalysts may be of the general formulae: {((R12N)3P═N—)x(R12N)3−xP—N(H)R2}+{A−} or {((R12N)3P═N—)y(R12N)4−yP}+{A}− in which R1 is hydrogen or an optionally substituted hydrocarbon group or in which two R1 groups bonded to the same N atom may be linked to complete a heterocyclic ring, R2 is hydrogen or an optionally substituted hydrocarbon group, x is 1, 2 or 3, y is 1, 2, 3 or 4 and A is an anion. Also claimed is a process which comprises mixing siloxanes having silicon-bonded groups R′ and cyclic or linear siloxanes having no silicon-bonded groups R′ with ionic phosphazene base catalysts and allowing the siloxane having silicon-bonded groups R′ to condense and the cyclic and linear siloxanes having no silicon-bonded R′ groups to polymerize by equilibration.
摘要:
The invention provides novel compounds of Formulas (I)-(IV), as described herein. Also provided are compositions of these compounds, method of making the compounds, and methods of using the compounds. The compounds can be used to regulate cholesterol homeostasis and to treat conditions and diseases associated with cholesterol homeostasis, including lysosomal lipid storage disorders such as Niemann-Pick Disease type C.
摘要:
The invention provides a variable focus lens formed from a ring with a front surface and a rear surface, a flexible membrane is attached to a radially inner part of the front surface, and a front cover is attached to a radially outer part of the front surface, a rear cover is provided on the rear surface of the ring, preferably integral with the ring, so that a variable volume cavity is defined between the flexible membrane, the ring and the rear cover, second flexible membrane can be provided between the ring and the rear cover, where the invention also provides a method of filling a variable focus lens, and an adjustment mechanism for varying the focus of the lens.
摘要:
A scaler positioning module may receive a video signal selected from among a plurality of video signals. The scaler positioning module may include scaler slots for arranging the signal path of the selected video signal through at least one scaler in the scaler positioning module. The scaler slots may enable the scaler positioning module to operate in three modes. The three modes may enable the scaler positioning module to output scaled data without memory operations, scale prior to a memory write, and scale after a memory read. A blank time optimizer (BTO) may receive data from the scaler positioning module at a first clock rate and distributed memory accesses based on a bandwidth requirement determination. The BTO may access memory at a second clock rate. The second clock rate may be slower than the first which may reduce memory bandwidth and enable another video signal to access memory faster.
摘要:
A submarine escape suit assembly comprises a submarine escape suit (10) and a liferaft pack (11). The pack (11) is formed by an outer casing (20) that can be pulled open to access a sealed inner casing (21) containing a liferaft. A cord (27) on the inner pack (11) is pulled to commence inflation of the liferaft (10).
摘要:
A system for sealing a packaging wrapper around an object directs a flow of heated air to end flaps of the wrapper to move the end flaps into sealing contact with a body section of the wrapper to substantially enclose the object. The system includes an oven, a conveyor, a source of heated air and a means for deflecting the flow of heated air to the conveyor to seal end flaps of the wrapper with a body section of the wrapper. In use, an object surrounded by the wrapper body section is moved through the oven on a conveying surface of the conveyor, and heated air is moved through the oven bypassing the conveying surface to a region below the conveying surface. The heated air flow then encounters the means for deflecting the heated air flow, which directs the air flow upward and through the conveying surface to impact and move the end flaps into sealing contact with the wrapper body section.