52results about How to "Low tensile modulus" patented technology

A polyurethane caulking material for expansion joints of a ballastless track of a high speed railway is disclosed. The caulking material is prepared from two parts A and B. the part A is composed of the following raw materials, by weight, 100 parts of isocyanate and its prepolymer, 10-150 parts of a plasticizer, 5-150 parts of a solid filler, 1-20 parts of a diluents, 1-5 parts of an adhesion promoter, 0-10 parts of a thixotropic agent and 1-3 parts of a water-removal agent. The part B is composed of the following raw materials, by weight, 10-20 parts of modified polyhydric alcohol, 1-5 parts of a diluent, 2-30 parts of a plasticizer, 5-30 parts of a solid filler, 0-5 parts of a thixotropic agent, 0.5-2 parts of an antifoaming agent, 0.1-1 part of an anti-aging agent and 0-0.01 part of a catalyst. The mass ratio of the part A to the part B is 4:1-10:1. The polyurethane caulking material has advantages of good low-temperature curing performance, high displacement capability, low tensile modulus, good bond property and excellent endurance quality and fatigue resistance, and is suitable for expansion joints of a ballastless track of a high speed railway as well as expansion joints of roads and airfield runways.

The invention relates to the technical field of building sealants, and in particular to single/double-component construction type polyurethane joint pouring glue for a ballastless track concrete expansion joint and a preparation method thereof. The single/double-component construction type polyurethane joint pouring glue for the ballastless track concrete expansion joint is prepared from a main agent and an accessory ingredient, wherein the main agent is prepared from a polyurethane prepolymer, filler, a thickening agent, a diluent, a catalyst, a cementation accelerator, a defoaming agent, a light stabilizer, an antioxidant and a water removing agent; the polyurethane prepolymer is prepared from polypropylene oxide glycol, polypropylene triol, polyisocyanate, a plasticizer and the catalyst; the accessory ingredient is prepared from the plasticizer, a thickening agent and micromolecular polyol. The preparation method comprises the following steps: step one, preparation of the polyurethane prepolymer; step two, preparation of the main agent; step three, preparation of the accessory ingredient. After the single/double-component construction type polyurethane joint pouring glue disclosed by the invention is cured, the tensile modulus is low, the anti-displacement capacity is strong, and low-temperature flexibility is good.

A tire cord (10) comprises a core (11) made of aramid fibers twisted together at a twist pitch (P1), and a sheath (12) composed of at least one strand (14) made of aramid fibers and wound around the core at a winding pitch (P2), wherein the winding pitch (P2) is less than the twist pitch (P1), and the total fineness (A) of the aramid fibers constituting the core (11) is less than the fineness (B) of the aramid fibers constituting each strand (14) of the sheath (12). A pneumatic tire (1) comprising a reinforcing layer, e.g. tread reinforcing layer made of the tire cords (10).

The invention discloses a single-ingredient oxime removal type low-modulus room-temperature vulcanization neutral silicone weather-resistant sealant, which is prepared from the following ingredients in parts by weight: 160 to 240 parts of basic polymers, 30 to 80 parts of light calcium carbonate, 100 to 160 parts of heavy calcium carbonate, 7 to 12 parts of thixotropic agents, 12 to 30 parts of simethicone, 8 to 15 parts of chain expansion agents, 13 to 19 parts of crosslinking agents, 2.5 to 5 parts of coupling agents and 0.2 to 0.4 part of catalysts. The prepared single-ingredient oxime removal type low-modulus room-temperature vulcanization neutral silicone weather-resistant sealant has the advantages of low stretch modulus, high elasticity, high elasticity recovery rate, excellent weather resistance and good bonding performance; after the treatment such as cold pulling-hot pressing and water soaking, the interface bonding damage and cohesive failure cannot occur; the promotion of the high-displacement jointing of the silicone sealant in the super high-rise building and the concrete expansion joint sealing of facilities such as roads, bridges and airfield runway can be facilitated.

The invention discloses a bio-based polyester modified polylactic resin, a preparation method and a processing forming method. The modified polylactic resin comprises 67-95wt% of polylactic acid, 4-30wt% of poly(butylene 2,5-furandicarboxylate), 0.5-1wt% of anti-oxidant and 0.5-2wt% of auxiliary agent. The preparation method is as follows: polylactic acid and poly(butylene 2,5-furandicarboxylate) are dried fully, then are subjected to banburying blending with the anti-oxidant and the auxiliary agent and a target product is obtained. The modified polylactic resin is renewable and environmental protection resin, the tensile strength is more than or equal to 60 MPa, the fracture percentage elongation is 180-240%, when the fracture percentage elongation is 240%, the tensile modulus is lowered by only 25%, and the tensile strength is lowered by only 16%, no pearl essence addition is needed, the surface has pearlescent color reflect light, and the modified polylactic resin can be used for preparing films, plates, sheets, foaming and injection molding plastic products and the like, and has wide industrial application prospects.

The invention relates to a sensitive material for a tensile deformation test and a preparation method thereof. The method comprises the following steps of: stirring and mixing liquid-state silicon rubber, chopped carbon fiber, conductive carbon black, nano-SiO2, a curing agent and a coupling agent serving as raw materials at normal temperature and under normal pressure in turn; removing air bubbles by vacuumizing; and molding. The obtained sensitive material for the tensile deformation test has high flexibility and very small tensile modulus and does not affect the deformation of a test structure or a test material in a testing process; and simultaneously, the sensitive material has the advantages of high sensitivity, performance stability, simple preparation method, wide raw material source and low manufacturing cost.

The invention discloses the application of a multifunctional organic gel as a conductive medium. The preparation raw materials of the multifunctional organic gel comprise a solvent, a monomer, a crosslinking agent, an electrolyte salt and an initiator, the volume ratio of the solvent to the monomer is 1:5 to 5:1, the molar ratio of the crosslinking agent to the monomer is 0.05% to 10%, the molar ratio of the initiator to the monomer is 0.1% to 10%, and the concentration of the electrolyte salt in a mixed solution of all the raw materials is 0.1 mol/L to 5 mol/L. When the organic gel is used asa conductive medium, since the organic gel has good electrical conductivity, a bulb can be lighted when the organic gel is used as a conductive line to energize the bulb, and an LED lamp bead can belighted when the organic gel is used as a conductive substrate to energize the LED lamp bead attached to the conductive substrate.

The invention belongs to the technical field of wave-absorbing materials, and discloses wave-absorbing composite foam and a preparation method thereof. An electromagnetic wave incoming surface comprises a glass fiber reinforced plastic layer, a wave-absorbing layer and a carbon fiber cloth reflecting layer sequentially from outside to inside, and an adhesive layer is arranged between the layers, wherein the wave-absorbing layer is obtained by (1) laying a layer of glass fiber cloth flatly; (2) applying a mixture of liquid thermosetting resin and curing agent onto the surface of the glass fibercloth by liquid electrostatic spraying; (3) vertically and directionally implanting a carbon wave-absorbing material on the basis of the step (2) by adopting an electrostatic flocking method; (4) forming a layer of hollow glass microspheres by powder electrostatic spraying; (5) continuously spraying a mixture of liquid thermosetting resin and curing agent; and (6) stacking a layer of glass fibercloth again on the basis of the step (5) to obtain the wave-absorbing layer. The wave-absorbing composite foam structure obtained herein allows weaponry to be efficiently invisible.

A copper alloy for electronic equipment comprises between 3.3 at% and 6.9 at% of Mg, with the balance being substantially Cu and inevitable impurities. When the Mg concentration is X at%, the conductivity sigma (% IACS) is within a range of sigma < {1.7241/(-0.0347 X2 + 0.6569 X + 1.7)} 100, and the stress relaxation percentage after 1,000 hours at 150 C is 50% or less.

The invention provides a high-intensity low-modulus metastable beta titanium alloy tooth arch wire which is characterized by comprising the following nominal chemical components in percentage by mass: 11 percent of Mo, 3 percent of Nb, 5 percent of Zr, 4 percent of Sn and the balance of titanium and unavoidable impurities. The tooth arch wire provided by the invention has good biocompatibility, high tensile strength, low elastic modulus, a wide elastic range and excellent resilience; moreover, the orthodontic force of the high-intensity low-modulus metastable beta titanium alloy tooth arch wire is lower than that of a stainless steel wire, but is higher than that of a nickel-titanium alloy wire, the elastic modulus of the high-intensity low-modulus metastable beta titanium alloy tooth arch wire is only one fourth to one third of that of the stainless steel wire, and the high-intensity low-modulus metastable beta titanium alloy tooth arch wire has a wider elastic range and a wider orthodontic displacement range than the stainless steel wire. Utilization of the tooth arch wire provided by the invention can obtain the stable and mild orthodontic force and durable and moderate displacement and can realize larger displacement of teeth without replacing an orthopedic wire or only by replacing the orthopedic wire a little.

The invention discloses a low-tensile-modulus one-component moisture cured polyurethane sealant. The low-tensile-modulus one-component moisture cured polyurethane sealant is prepared from, by weight, 15-25 parts of isophorone diisocyanate, 30-45 parts of two-functionality polyether polyol, 10-20 parts of three-functionality polyether polyol, 0-0.5 part of dibutyltin dilaurate, 20-30 parts of calcium carbonate, 5-10 parts of hydrophobic modified gas-phase silicon dioxide, 0.5-1.5 parts of oxazolidinone and 0.5-1.5 parts of iron oxide black. The invention further provides a method for preparing the low-tensile-modulus one-component moisture cured polyurethane sealant. The one-component moisture cured polyurethane sealant still has lower tensile modulus at low temperature; meanwhile, the one-component moisture cured polyurethane sealant further has good tensile strength and excellent elongation at break and elastic recovery, and the comprehensive mechanical property is excellent.

The invention discloses a synthesis method of a phenoxy resin. The method comprises the following steps: 1) uniformly mixing a bisphenol A epoxy resin and BPA (bisphenol A) in a tank reactor, adding an ether solvent or ketone solvent, and heating until the materials are dissolved; 2) adding a catalyst, and heating to react; 3) when the molecular weight of the reaction product reaches 28000-32000, adding a mixed solvent into the tank reactor at uniform speed within 2-5 hours; and 4) filtering and discharging to obtain the phenoxy resin. The phenoxy resin prepared by the method has the advantages of favorable flowability, low viscosity and low facility requests, can perform reaction in the tank reactor, and is suitable for large-scale production. The phenoxy resin has moderate molecular weight, is suitable for participating in blending, and is used as a modifier for plastics, adhesives, paints and other resins. The added phenoxy resin can improve the flexibility of the curing system, lower the stretch modulus of the curing system and enhance the elongation percentage.

The invention discloses a room-temperature vulcanized neutral silicone weather-proof sealant which comprises the following components in parts by weight: 160-240 parts of basic polymer, 30-80 parts oflight calcium carbonate, 100-160 parts of heavy calcium carbonate, 3-6 parts of nitrogen-doped graphene, 12-30 parts of simethicone, 8-15 parts of chain extender, 13-19 parts of cross-linking agent,2.5-5 parts of coupling reagent and 0.2-0.4 part of catalyst; the basic polymer is polydimethylsiloxane with two ends terminated by hydroxy; the viscosity of the basic polymer at 25 DEG C is 60000-75000mPa.s. The silicone weather-proof sealant provided by the invention has low tensile modulus, high elasticity, high elasticity recovery rate, excellent weather fastness and excellent adhesive property; after the silicone weather-proof sealant is treated in the manner of cold draw-hot press, water soaking, and the like, the silicone weather-proof sealant is free from interface adhesion failure andcohesive failure; the high-displacement joint filling of the silicone sealant in super high-rise buildings and the sealing for concrete expansion joints of facilities, such as roads, bridges and airport runways, can be promoted.

The present disclosure provides catheters comprising polytetrafluoroethylene (PTFE) tubes with advantageous combinations of strength, flexibility, and size. Such tubes can exhibit features including an average wall thickness of 0.001″ or less, a tensile stress at break of greater than 5000 psi, and a storage modulus of less than 100,000 psi at 37° C. These tubes can be also be provided independently (i.e., not within a catheter) and can be employed in various applications.

The invention relates to the field of polymer materials, and discloses a preparation method of a lactic acid copolymer with high relative molecular mass. The preparation method comprises the steps ofpreparing a PLA prepolymer, preparing a PCL prepolymer and preparing a PLA copolymer through double-screw reactive extrusion. Polylactic acid with a certain relative molecular mass is synthesized by amelt polycondensation method and then is copolymerized with a polyurethane prepolymer of polycaprolactone polyol, the lactic acid copolymer is extruded by a double-screw reactor to prepare the lacticacid copolymer with high relative molecular mass, and the lactic acid copolymer prepared through the double-screw reactive extrusion is thermoplastic and has a better mixing effect than a kettle-typereaction. Through reasonable configuration, the product obtained through double-screw reactive extrusion has good mechanical properties, the toughness of the reaction extrusion product is improved due to increase of the PCL content, and the tensile strength and the tensile modulus are reduced.

The invention discloses a low-modulus room temperature vulcanization neutral silicone weather-proof sealant. The low-modulus room temperature vulcanization neutral silicone weather-proof sealant is prepared from, by weight, 160-240 parts of basic polymer, 30-80 parts of light calcium carbonate, 100-160 parts of coarse whiting, 3-6 parts of graphene oxide, 12-30 parts of dimethyl silicone, 8-15 parts of chain extender, 13-19 parts of cross-linking agent, 2.5-5 parts of coupling agent and 0.2-0.4 part of catalyst. The basic polymer is polydimethylsiloxane with two hydroxyl terminated ends, and the viscosity of the basic polymer under the temperature of 25 DEG C is 60,000-75,000 mPa s. The silicone weather-proof sealant has the low tensile modulus, high elasticity and high elastic recovery rate, excellent weather resistance and good adhesive property; after cold-drawing, hot-pressing, water immersion and other treatment, no interface bonding damage or cohesive failure appear, high-displacement jointing of the silicone weather-proof sealant in a super high-rise building is promoted, and concrete expansion joint sealing of facilities such as a road, a bridge and an airport pavement is facilitated.