97results about How to "Avoid volume shrinkage" patented technology

The invention belongs to the technical field of liquid crystal application and especially relates to a preparation method of a polymer mixed network-based polymer dispersed liquid crystal (PDLC) film material. The preparation method of the polymer mixed network-based PDLC film material is characterized in that one or more ultraviolet light polymerisable epoxy monomers, an ultraviolet light polymerisable acrylate (or methacrylate) monomer, nematic liquid crystals, a cationic photoinitiator, a free radical photoinitiator and glass beads are uniformly mixed according to a certain mass ratio; the mixture is coated between two transparent indium tin oxid (ITO) conductive plastic films and then is pressed into films having different thickness values; and the films are irradiated by ultraviolet lights having wavelength of 365nm to be cured into the polymer mixed network-based PDLC film material. The polymer mixed network-based PDLC film material obtained by the preparation method has the advantages belonging to an acrylate or methacrylate network-based PDLC film and an epoxy resin network-based PDLC film. The preparation method improves the cohesion between a polymer network and an ITO plastic film interface, and improves the stability of the polymer mixed network-based PDLC film material.

The invention relates to a denitrification and VOC removing catalyst, and belongs to the field of environmental protection catalysts. According to the present invention, the Mo-V-W / TiO2-Al2O3 system is formed among various components of the catalyst, such that the functions of denitrification and VOC removing can be concurrently achieved under the effect of the active components such as Mo, V and W and the carrier TiO2-Al2O3, the structure of the tail gas filtration discharging equipment can be effectively simplified, and the environmental protection cost can be reduced; and the denitrification and VOC removing catalyst has the high dust interference resistance, and can provide the maximum filtration performance on the basis of no requirement of the frequent stopping-dust cleaning, such that the catalyst has advantages of uniform aging speed, strong filtration ability, and long service life.

The invention discloses a method for controlling the medium-temperature strength of gel-cast ceramic parts. The method comprises the steps of firstly, adding organic monomers, a cross-linking agent and a dispersant sodium polyacrylate into diluted silica sol, so as to obtain a premix, then, adding polysiloxane, ceramic powder and polyimide, and carrying out ball milling, so as to obtain ceramic slurry, carrying out in-situ curing, then, carrying out freeze drying, and carrying out degreased pre-sintering, impregnation aftertreatment and final-sintering, thereby obtaining the ceramic parts. According to the method, polyimide has adhesion property due to the high-temperature resistance of polyimide, a reticular structure is formed due to the low-temperature cross-linking of polysiloxane, a role in adhering ceramic granules is played, after freeze drying, silica sol is dehydrated, so as to form a silicon-oxygen bond three-dimensional reticular structure, and the medium-temperature strength of ceramic blanks at a degreasing stage can be remarkably improved due to the synergism of polyimide, polysiloxane and silica sol; the method can be applied to the preparation of the gel-cast ceramic parts, and the medium-temperature strength of the ceramic blanks at the degreasing stage is effectively controlled, so that the integrity of the ceramic parts can be guaranteed.

The invention discloses an LED molding sealing device and a sealing method thereof. The device comprises an upper mold, a lower mold and a glue channel partition structure. The upper part of the upper mold is provided with a glue injection port, the upper part of the lower mold is provided with a cavity, and the glue injection port The cavity is connected to the mold cavity through the glue channel set on the lower part of the upper mold and the upper part of the lower mold. The upper mold and the lower mold are locked by the locking parts. It also includes the glue channel partition structure set in the glue channel. The glue channel partition structure is shifted to connect the rubber channel. When the glue injection is completed, the glue thrust disappears, and the glue channel partition structure is reset to automatically isolate the glue channel. The present invention is applicable to the LED sealing field. The present invention not only has a simple structure and is convenient to use, but also can well maintain the pressure of the glue in the mold cavity when the sealing is completed, avoiding volume shrinkage during the heat curing process of the sealing glue, and ensuring the sealing effect. The colloid of the finished product is complete, increasing the yield of the molded product.

The invention discloses a preparation method of a novel bamboo steel composite material, and belongs to the technical field of bamboo artificial boards and bamboo engineering materials. The method comprises the following steps: (1) removing lignin and hemicellulose in the bamboo wood by a two-step method, (2) breaking through a pore structure in the bamboo wood by using a freeze-drying process, (3) carrying out vacuum impregnation epoxy resin treatment on an obtained bamboo wood framework, and (4) carrying out hot-pressing curing to realize densification of the bamboo wood, thereby obtaining the bamboo-steel composite material with high fiber content. The bamboo steel material provided by the invention has the advantages of high bamboo utilization rate, excellent mechanical properties, high dimensional stability, low thermal conductivity and the like, and is expected to be applied to the fields of energy-saving buildings, bridges, transportation, aerospace and the like.

The invention discloses a heat conduction graphite paster for adhesive tape and a preparing method of the heat conduction graphite paster. The surface of the heat conduction graphite paster is coated with a heat conduction adhesive layer, the heat conduction graphite paster is composed of a polyimide film, a first coating layer and a second coating layer, and the first coating layer and the second coating layer are located on the upper surface and the lower surface of the polyimide film respectively. The first coating layer and the second coating layer respectively comprise, by weight, 20-25 parts of benzophenone tetracid dianhydride, 12-18 parts of pyromellitic acid dianhydride, 20-28 parts of diaminodiphenylmethane, 20-25 parts of dimethyl formamide, 8-10 parts of N-methyl pyrrolidone, 1.5-2.5 parts of ethylene glycol, 2-3 parts of dimethyl silicone polymer and 0.8-1.5 parts of phthalic acid dibutyl ester. According to the heat conduction graphite paster, local overheating is avoided, the evenness of the heat conduction performance is achieved, the stability and reliability of the heat dissipation performance of the heat conduction graphite paster are improved, and the cost of the heat conduction graphite paster is reduced.

The invention provides an environmental barrier coating. The environmental barrier coating is composed of a SiC bonding layer, a mullite middle layer and an ytterbium silicate outer coating, which coat a C / SiC composite material and are sequentially arranged from inside to outside. The C / SiC composite material coated by a SiC coating is prepared by a secondary chemical vapor deposition (CVD) method; the mullite middle layer is prepared by combining a sol-gel method with an air spraying technology, and the ytterbium silicate outer coating is prepared by combining a solid phase sintering technology with an air spraying technology. Through a smart EBC coating system and a preparation process, the ytterbium silicate outer coating is prepared by combining a solid phase sintering technology withan air spraying technology for the first time, the mullite middle layer and the ytterbium silicate outer coating are tightly combined, and the coating is compact and free of cracks. The traditional sol-gel process is improved to a great extent, the defects of cracking, peeling and poor binding force in the sintering process of a coating prepared through a traditional sol-gel method are maximallyovercome, and the use requirements of large components and special-shaped parts can be met.