99results about How to "Low coefficient of linear thermal expansion" patented technology

The invention relates to a flame-retardant heat-conducting double-component epoxy resin pouring sealant and a preparation method thereof. The pouring sealant is composed of a component A and a component B in a weight ratio of 100: 80 to 100: 120. The pouring sealant prepared in the invention has the advantages of a long operation period, a low thermal expansion coefficient after curing, a high flame retardation grade, reaching grade UL94-V0, good thermal conductivity and excellent electrical properties, and is applicable to high temperature electric packaging of power semiconductors, rectifiers, transformers, etc.

The invention discloses a protective sealing door for an underground refuge chamber. The protective sealing door comprises a door frame and a door plate, wherein the door plate is arranged on the door frame through a rotation shaft; a locking mechanism for locking the door plate on the door frame is arranged on the door plate, a plurality of first reinforcing ribs for reinforcing the strength of the door plate are arranged in the door plate; heat-insulating materials, namely aerogel heat-insulating felts are filled among the reinforcing ribs; at least two annular sealing rings, namely flame-resisting sealing rings are arranged at the joint of the door plate and the door frame; and the periphery of the door plate is locked by the locking mechanism. According to the protective sealing door, the aerogel heat-insulating felts which can bear the temperature of 1,400 DEG C to the maximum are filled in the door plate, so that the door plate can resist high temperature generated during explosion, and the high temperature is insulated out of the refuge chamber; at least two sealing rings which are made of flame-resisting, anti-static, high temperature-resisting and oil-resisting materials are arranged on the contact surface of the door plate and the door frame, so that the protective sealing door has a good sealing effect.

The present invention addresses the problem of providing: a polyimide which has excellent transparency, high heat resistance and low linear thermal expansion coefficient at the same time, while exhibiting solvent workability (excellent solubility and film formation performance) by means of a low moisture-absorbing solvent; and a method for producing this polyimide. In order to solve the above-mentioned problem, the present invention provides a polyimide that contains a constituent unit represented by formula (1). (In the formula, each R independently represents a hydrogen atom or an alkyl group having 1-6 carbon atoms, provided that at least one of two R groups bonded to a same benzene ring is an alkyl group.)

The invention discloses a halogen-free fire-retardant PTB/PC alloy composition and a preparation method thereof. The formula of the composition comprises the following components in mass percentage: 40 to 50 percent of PBT, 10 to 20 percent of PC, 23 to 33 percent of active magnesium hydrate, 3 to 7 percent of organic phosphate oligomer, 3 to 7 percent of polysiloxane/acrylic ester grafting copolymer, 3 to 7 percent of novolac epoxy, 0.2 to 0.4 percent of antioxidant and 0.4 to 0.8 percent of processing aid. In the formula of the method, all components are dispersed to be mixed and are subject to melting by a double screw extruder, mixing, extrusion, cooling, drying, granulating and packaging. In the invention, the fire-retardant char-forming actions of all added components are combined with the interaction of interfaces of a substrate, which makes the components of the system form an indispensable organic whole, so that the higher fire retardant performance is achieved under the lower consumption of the magnesium hydrate, and the mechanical property, the thermal property and the processability of the system are also good.

The invention discloses a direct coating method for preparing a non-curling high-adhesiveness glue-free flexible copper-clad plate. The method comprises the following steps: firstly, dissolving an aromatic diamine monomer containing a benzoxazole structure, an aromatic diamine monomer containing a keto ether structure, an aromatic diamine monomer containing a full-ether link structure and an aromatic dianhydride monomer in an aprotic polar solvent to prepare a polyamic acid glue solution by a polymerization; then, coating the polyamic acid glue solution on a copper foil with the thickness of 6-35 microns; baking at 50-150 DEG C for 5-180 minutes; then, arranging in a vacuum oven or a high-temperature drying tunnel in nitrogen atmosphere for phasic thermocuring respectively at 80 DEG C, 120 DEG C, 180 DEG C, 220-280 DEG C and 320-380 DEG C, wherein each thermocuring phase keeps 10-90 minutes. The glue-free flexible copper-clad plate prepared by the method not only has high adhesiveness, no curling and high peeling strength, but also has excellent chemical performance, heat resistance, favorable bending resistance and lower water-absorbing rate. The method has once coating molding, simple preparation process and lower production cost.

A kind of multifunctinoal epoxy resin and its preparation method is involved in this invention. In the formula, A3 is selected from hydrogen atom, cymene, methoxy, bromine atom, R1, R2, R3 are shrink glycerin aethers, the value of n lies between 0 and 8. The preparation process of the method includes: firstly, hydroxy naphthalene compound and bifunctional aldehyde or ketone shrink in the presence of proton acid activator, and multihydroxy naphthalene compound is gained, and then it makes aether reaction with PAE in the action of alkali activator. The epoxy resin has good capability such as high heat-resistance, low moisture absorption and low expandability etc., and fits madding glass cloth or epoxy resin pressing board covering copper and foil, and encapsulation of semiconductor component and IC, so it has capacious application foreground in the electronic industry.

The invention discloses a high heat-resistant nylon/acrylonitrile-butadiene-styrene resin mixed material, which consists of nylon in an amount of 50 to 75 parts by weight, ABS resin in an amount of 10 to 25 parts by weight, styrene-N-phenyl maleimide copolymer in an amount of 5 to 15 parts by weight, and an inorganic filler in an amount of 5 to 15 parts by weight. The heat-resistant nylon/acrylonitrile-butadiene-styrene resin mixed material has excellent heat resistance, chemical resistance and mechanical property, and has the characteristics of low coefficient of linear thermal expansion, and excellent liquidity, so as to be sprayed on line, and be used for manufacturing such components as automobile fenders, rearview mirrors, tank cups and so on.

The invention discloses a polyamide-imide, a polyamide-imide film and a display device comprising the film. The polyamide-imide comprises at least two different block structures, wherein the first block has a repeating unit with a structure shown in the following formula I, and the second block has a repeating unit with a structure shown in the following formula II. The film prepared from the multi-block polyamide-imide has excellent solubility, heat resistance and mechanical properties, low thermal expansion coefficient performance, high light transmittance and relatively low cut-off wavelength, so that the film can be used as a display device material of a flexible display, and is particularly suitable for being used as a substrate material in the display.

The invention discloses an antistatic spray-free polypropylene composite material with low linear thermal expansion coefficient and a preparation method of the antistatic spray-free polypropylene composite material. The antistatic spray-free polypropylene composite material is prepared by mixing and extruding polypropylene, mineral filling, a toughening agent, a functional assistant, a metal pigment, a coupling agent, an antioxidant, a lubricant and a light stabilizer. The functional assistant is prepared by compounding wollastonite whisker and glyceryl monostearyl ester according to the mixing mass ratio of 1:1 to 4:1. According to the antistatic spray-free polypropylene composite material, the polypropylene is compounded with the mineral filling and the toughening agent, the strength, rigidity and toughness of the composite material are ensured, in addition, the crystallization velocity is shortened and the degree of crystallization of the material is increased by adding the functional assistant, the post shrinkage of the product is lowered, the forming period of the product is shortened, meanwhile a conductive network is formed in the material, the material has a certain conductive performance, the surface antistatic property of the material is improved, and thus the modified polypropylene composite material can be widely used in spray-free products.

The invention discloses a reinforced ABS resin composition suitable for electroplating. The composition comprises 85-96wt% of an ABS resin, 3-10wt% of a carbon fiber, 0.1-1.0wt% of a dispersant, 0.01-1.0wt% of a lubricant, 0.1-1.0wt% of a main antioxidant and 0.5-2.0wt% of an auxiliary antioxidant. The reinforced ABS resin composition suitable for electroplating can reduce the linear thermal expansion coefficient of a plastic electroplating product, has an above 50% lower linear thermal expansion coefficient than a common ABS resin, and can well meet the performance requirements of the plastic electroplating product. The adoption of the carbon fiber enhances the conductivity of the ABS resin, effectively increases the bonding force between the ABS resin and an electroplating layer, shortens the pretreatment time of electroplating, improves the electroplating production processing efficiency, and is in favor of the electroplating production. The reinforced ABS resin composition suitable for electroplating has high mechanical strength and good dimensional stability.

A polyester-imide precursor characterized by having repeating units represented by the following formula (1). (In the formula (1), Ar is the tetravalent aromatic group represented by the formula (2) and B1 is an ester structure having a specific structure.).