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7949results about How to "High molecular weight" patented technology

Biodegradable low molecular weight triblock poly (lactide-co-glycolide) polyethylene glycol copolymers having reverse thermal gelation properties

A water soluble biodegradable ABA- or BAB-type triblock polymer is disclosed that is made up of a major amount of a hydrophobic polymer made of a poly(lactide-co-glycolide) copolymer or poly(lactide) polymer as the A-blocks and a minor amount of a hydrophilic polyethylene glycol polymer B-block, having an overall weight average molecular weight of between about 2000 and 4990, and that possesses reverse thermal gelation properties. Effective concentrations of the triblock polymer and a drug may be uniformly contained in an aqueous phase to form a drug delivery composition. At temperatures below the gelation temperature of the triblock polymer the composition is a liquid and at temperatures at or above the gelation temperature the composition is a gel or semi-solid. The composition may be administered to a warm-blooded animal as a liquid by parenteral, ocular, topical, inhalation, transdermal, vaginal, transurethral, rectal, nasal, oral, pulmonary or aural delivery means and is a gel at body temperature. The composition may also be administered as a gel. The drug is released at a controlled rate from the gel which biodegrades into non-toxic products. The release rate of the drug may be adjusted by changing various parameters such as hydrophobic/hydrophilic componenet content, polymer concentration, molecular weight and polydispersity of the triblock polymer. Because the triblock polymer is amphiphilic, it functions to increase the solubility and/or stability of drugs in the composition.
Owner:BTG INT LTD +2

High melting thermoplastic elastomeric alpha-olefin polymers (PRE/EPE effect) and catalysts therefor

InactiveUS6559262B1Activity of fluxional unbridged metallocene polymerization catalystsHigh molecular weightGroup 4/14 element organic compoundsMetallocenesElastomerEthylene Homopolymers
This invention relates generally to low ethylene insertions into I-olefin polymers and processes for production of such polymers using unbridged fluxional metallocenes, primarily substituted aryl indenyl metallocenes, and more particularly to use of unbridged, fluxional, cyclopentadienyl or indenyl metallocene catalyst systems in methods of production of high melting point I-olefin homo- and co-polymers, particularly elastomeric crystalline and amorphous block homo- and co-polymers of I-olefins. The activity of fluxional unbridged metallocene polymerization catalysts containing at least one 2-arylindene ligand is increased 10x or more by the addition of small (typically 0.1-10 wt. %) amounts of ethylene to the polymerization system, which increase is termed the Polymerization Rate-Enhancement effect (PRE), which is measured in terms of an Ethylene Enhancement Factor (EEF) as a dimensionless ratio in the range of from about 1.1 to about 10 or above. The amount of ethylene included in the reaction system can be selected and controlled to be so small as to result in essentially minimal (<2 mole %) incorporation of ethylene units into the resulting elastomeric polymer and the molecular weight may be increased. Amounts of ethylene to generate the PRE effect may be greater than 0.1 wt. % and preferably range up to about 2 wt. %. However, if a polymer with more ethylene is desired, additional ethylene may be incorporated into the polymerization feed, including up to 10 to about 50 mole % based on olefin units. A second important aspect of this invention is the ability to use a PRE activity-enhancing amount of ethylene in an olefin polymerization without substantially affecting the physical properties of the elastomer. In a third important aspect of this invention, I-olefin elastomers are produced through incorporation of ethylene using unbridged fluxional catalyst systems which may not otherwise produce acceptable elastomeric homopolymers. This effect is termed the EPE effect, for Elastomeric Property-Enhancing effect. The EPE amount of ethylene required to produce such elastomers typically overlaps the PRE activity-enhancing amount. Incorporation of up to about 5 mole % or more of ethylene typically will produce an elastomeric polymer using such catalyst systems. Typical useful amounts of incorporated ethylene include about 1 to 3 mole %. Preferred polymers of this invention retain sufficient crystallinity to provide a high melting point (by DSC) of about 80° C., preferably above 100° C., including in the range of from about 120° C. to about 140° C. and above. Novel flexible alpha-olefin homo and copolymers having elongation in excess of 600% and substantially no retained force are disclosed.
Owner:BP CORP NORTH AMERICA INC

Water-based polyurethane composite adhesive for tanning and preparation method and application of composite adhesive

InactiveCN102618202ATroubleshoot MigrationOvercome the problem that the performance cannot fully meet the requirements of useNon-macromolecular adhesive additivesPolyureas/polyurethane adhesivesPolymer sciencePolyol
The invention discloses water-based polyurethane composite adhesive for tanning and a preparation method and application of the composite adhesive, belongs to the technical field of water-based polyurethane composite adhesive preparation methods, and in particular relates to a method for preparing composite adhesive in the fields of artificial leather and synthetic leather. The method for preparing the water-based polyurethane composite adhesive for tanning is characterized by comprising the following steps of: reacting polyol polymer and isocyanate, adding chain extender, hydrophilic chain extender, cross linker, catalyst and solvent, reacting, cooling and emulsifying, to obtain emulsion; and mixing the emulsion, curing agent, wetting agent, tackifier, adsorbent and thickening agent uniformly, and thus obtaining the hot-melt adhesive for artificial leather adhesive layers. The water-based polyurethane composite adhesive for tanning is used for compounding polyvinyl chloride (PVC) / cloth for artificial leather of luggage and clothes. The prepared water-based polyurethane composite adhesive for tanning has high adhesive fastness and good water and solvent resistance, and can be applied to processes of knife coating, roll coating and the like of binding materials of middle layers of artificial leather and synthetic leather in the fields of textiles, leather processing and the like.
Owner:江阴市诺科生物新材料科技有限公司

Temperature-resistant salt-resistant efficient gel, and preparation and use thereof

The invention discloses a temperature resistant salt tolerant high efficiency gel and a preparation method and application thereof. The preparation method is characterized in that the preparation method comprises the following steps: preparing a comb-shaped associated copolymer PAH containing macromonomers and functional hydrophobic monomers into an aqueous solution having the concentration of 0.1 to 4g/L, the crosslinking agent concentration of 0.01 to 1.0g/L, the surfactant concentration of 0.01 to 8mmol/L and the sodium sulfite thermal stabilizer concentration of 0.005 to 1.0g/L; adding the aqueous solution into a mixing container with a stirring device; stirring the aqueous solution evenly at the room temperature; regulating the pH value of the solution to be equal to between 4 and 11, and obtaining a temperature resistant salt tolerant high efficiency gel polymer solution system used for tertiary oil recovery and scavenge, displacement modification, profile modification or water shutoff. The polymer solution system has micro-crosslinking to form the gel during the flowage inside the oil reservoir. The gel has good elasticity, not easy dehydration, stable gelling performance, and excellent tackification, temperature resistance, salt tolerance, shearing resistance and ageing resistance.
Owner:CHENGDU UNIVERSITY OF TECHNOLOGY

Methods of forming a doped semiconductor thin film, doped semiconductor thin film structures, doped silane compositions, and methods of making such compositions

Methods for forming doped silane and / or semiconductor thin films, doped liquid phase silane compositions useful in such methods, and doped semiconductor thin films and structures. The composition is generally liquid at ambient temperatures and includes a Group IVA atom source and a dopant source. By irradiating a doped liquid silane during at least part of its deposition, a thin, substantially uniform doped oligomerized / polymerized silane film may be formed on a substrate. Such irradiation is believed to convert the doped silane film into a relatively high-molecular weight species with relatively high viscosity and relatively low volatility, typically by cross-linking, isomerization, oligomerization and / or polymerization. A film formed by the irradiation of doped liquid silanes can later be converted (generally by heating and annealing / recrystallization) into a doped, hydrogenated, amorphous silicon film or a doped, at least partially polycrystalline silicon film suitable for electronic devices. Thus, the present invention enables use of high throughput, low cost equipment and techniques for making doped semiconductor films of commercial quality and quantity from doped “liquid silicon.”
Owner:ENSURGE MICROPOWER ASA
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