EVA hot melt adhesive is a solvent-free, water-free, 100% solid fusible polymer. It is solid at room temperature and becomes a liquid adhesive that can flow and has a certain viscosity when heated and melted to a certain degree. It is light brown translucent or white after melting. EVA EVA hot melt adhesive has the following characteristics: (1). It has fast curing, low pollution, strong adhesion, and the adhesive layer has certain flexibility, hardness, and toughness; (2). After the adhesive liquid is applied to the adherend and cooled and solidified, the adhesive layer can be heated and melted again to become an adhesive body and then bonded to the adherend, with a certain degree of re-adhesion; (3). When using, just heat and melt the hot melt adhesive into the required liquid state and apply it to the adherend. After pressing, the bonding and curing can be completed within a few seconds, and the hardening, cooling and drying can be achieved within a few minutes. The type of EVA determines the cohesive strength, flexibility, adhesion to the substrate and processability of the hot melt adhesive. For hot melt adhesive, the following properties of EVA should be paid attention to: molecular weight and its distribution, vinyl acetate (VA) content, crystallinity, softening point, melting point, melt index (MI) and melt viscosity, etc., because these properties directly affect the various properties of hot melt adhesive. As the melt index of EVA increases, its strength, hardness, softening point and viscosity all decrease regularly; and the more VA content in EVA, the greater the elongation at break and the lower the hardness. In addition, when the VA content exceeds 30%, although the adhesion to polar and various non-porous non-polar substrates is improved, this EVA polymer is incompatible with wax, which is a point to be noted when designing hot melt adhesive formulas. In a formula, it is often necessary to use EVA with different MI or EVA with different VA content to obtain satisfactory comprehensive performance. Website: www.elephchem.com Whatsapp: (+)86 13851435272 E-mail: admin@elephchem.com ElephChem Holding Limited, professional market expert in
Introduction to polyvinyl acetate
Polyvinyl acetate (PVAC) China's vinyl acetate The application fields of PVAc emulsion are very wide: 1. Construction industry, can be used for interior wall decorative coatings, colorful coatings, etc. It is also used for cement modification to improve the tensile strength, adhesion and chemical stability of cement mortar or concrete, and to prevent cracking, etc. 2. In the building materials industry, adhesive glue can be produced, such as woodworking glue, white latex, furniture glue, super glue, etc. 3. Paper industry, can be used as adhesive, impregnating agent, rewetting adhesive, 4. Packaging printing, can be used for plastic-plastic bonding, aluminum-plastic bonding, and post-processing of printed paper products In addition, it has certain applications in textile printing and dyeing, fiberglass processing, and biomedicine. Website: www.elephchem.com Whatsapp: (+)86 13851435272 E-mail: admin@elephchem.com ElephChem Holding Limited, professional market expert in Polyvinyl Alcohol
Introduction to Polyvinyl Butyral resin
PVB (Polyvinyl Butyral PVB resin has good weather resistance against ultraviolet radiation and atmospheric oxidation, and can provide long-term protection. Bonds well to glass and other materials. This makes PVB film Because PVB resin has good transparency and optical properties, it is a transparent material with a high refractive index and low hygroscopicity. It is widely used in fields such as optical coatings, optical films and optical glasses. PVB can also be used for flexo printing, gravure printing, embossing printing, screen printing, and thermal transfer printing in the printing industry. Because it is soluble in alcohol and non-toxic, the printed parts do not retain odor, and can be used in packaging that is sensitive to odor in the food industry. Such as teahttps://www.elephchem.comcigarettes, etc. Because the resin is cationic, it has adhesion to glass surfaces with strong anions, and is especially suitable for glass plate decorative silk screen printing. Website: www.elephchem.com Whatsapp: (+)86 13851435272 E-mail: admin@elephchem.com ElephChem Holding Limited, professional market expert in
Introduction to the production process of vinyl acetate
Vinyl acetate is a colorless flammable liquid with a strong odor. Its vapor is irritating to the eyes. It is insoluble in water but soluble in most organic solvents. Vinyl acetate monomer is flammable and reacts rapidly with chlorine, bromine, and ozone. There are two production process routes for vinyl acetate monomer: the ethylene method and the acetylene method. The acetylene method can be divided into a liquid phase method and a gas phase method, and the ethylene method can also be divided into a liquid phase method and a gas phase method. Acetylene gas phase method: desulfurized and dephosphinated calcium carbide acetylene and acetic acid are used as raw materials, the catalyst is zinc acetate-activated carbon (15:100), and a promoter is added. The reaction temperature is 170~200℃, the pressure is atmospheric pressure, and the space velocity is 200~400https://www.elephchem.comh. Reaction results: acetic acid single-pass conversion rate is 25~40%, acetylene single-pass conversion rate is 12~16%. The selectivity of VAM is 92~96% for acetylene and 95~98% for acetic acid. The total yield of VAM is 97~98% for acetic acid and 92~96% for acetylene. The catalysts for the ethylene gas phase process are mainly Pd-Au, Pd-Pt and Pd-Cd supported catalysts, and the carriers are mainly silica gel and alumina. The two main factors affecting the catalyst are the coordination ability of Pd and the ability of acetic acid or acetate to oxidize Pd(0) to Pd(II). The single-pass conversion rate of ethylene in this process is 8~10%, the single-pass conversion rate of acetic acid is 8~20%, and the VAM selectivity based on ethylene is 90~94%. In the past few years, the acetylene process has been gradually replaced by the ethylene process due to the high cost of raw materials. However, with the continuous rise in oil prices, the acetylene process has regained economic vitality, especially the acetylene process using natural gas as raw material. At present, the acetylene process still occupies an important position in China. The ethylene gas phase process occupies a dominant position in the market due to its good processability and economic performance. At present, the ethylene production technology in China accounts for more than 55% of the total national production capacity. Website: www.elephchem.com Whatsapp: (+)86 13851435272 E-mail: admin@elephchem.com ElephChem Holding Limited, professional market expert in
Medical applications of polyvinyl alcohol microspheres
Polyvinyl alcohol (PVA) Polyvinyl alcohol foam embolic microspheres are medical substances used for embolization of blood vessels. They are mainly composed of polyvinyl alcohol andhttps://www.elephchem.comor polyglycolide and are specially treated to enable them to swell and embolize blood vessels. Such microparticles are often used in intravascular surgery to prevent blood from flowing into and contaminating the surgical area. In addition, they can also be used to treat ischemic stroke and other vascular diseases. Features of polyvinyl alcohol foam embolic microspheres include: it can swell upon contact with blood and quickly solidify, thereby effectively embolizing blood vessels. The microspheres are degradable and will be absorbed by the body after a period of time, which helps reduce the risk of complications. In addition, it can be combined with other substances (such as drugs) to achieve specific therapeutic purposes. When using polyvinyl alcohol foam embolic microspheres, strict guidelines and standard operating procedures need to be followed. These microspheres are usually inserted into blood vessels by medical professionals when using endovascular procedures. Website: www.elephchem.com Whatsapp: (+)86 13851435272 E-mail: admin@elephchem.com ElephChem Holding Limited, professional market expert in Polyvinyl Alcohol
Preparation of thermal conductive PVA films
As a new type of thermal conductive material, thermal conductive PVA (polyvinyl alcohol) film has excellent thermal conductivity, good mechanical strength and processing performance. The preparation of thermal conductive PVA film mainly includes raw material selection, blending modification, film forming process and post-processing. Raw material selection: The main raw material of thermal conductive PVA film is polyvinyl alcohol resin, and a certain amount of thermal conductive filler, such as oxygen, needs to be added Aluminum, boron nitride, etc. The addition of these fillers can effectively improve the thermal conductivity of PVA films. Blending modification: the polyvinyl alcohol resin is mixed with the thermal conductive filler in a certain proportion, and the blending modification is carried out by high-speed stirring, ball milling and other methods. During the blending process, the filler particles are uniformly dispersed in the resin matrix to form a thermal conductivity network, thereby improving the thermal conductivity of the material. Film forming process: the blended modified slurry is made into a film by casting, calendering or extrusion processes. In the film forming process, parameters such as temperature, pressure and speed need to be controlled to ensure the thickness, uniformity and surface quality of the film. Post-treatment: Post-treatment processes such as drying and heat setting need to be carried out after film formation to eliminate the internal stress inside the film and improve dimensional stability. Website: www.elephchem.com Whatsapp: (+)86 13851435272 E-mail: admin@elephchem.com ElephChem Holding Limited, professional market expert in Polyvinyl Alcohol
Properties and applications of EVA film
EVA film is a thermosetting and sticky film, mainly used in the middle of laminated glass. It has the characteristics of high transparency, high adhesion, good durability and easy storage. High transparency allows light to penetrate better, reducing light energy loss and improving photoelectric conversion efficiency. High adhesion, able to firmly bond various materials, effectively ensuring the stability between components. Good durability, able to resist high temperature, moisture, ultraviolet rays and other environmental factors, ensuring long-term use. Easy to store, it can be stored at room temperature and is not affected by humidity and water absorption. Low melting point, easy to flow, suitable for lamination process of various glass, such as patterned glass, tempered glass, curved glass, etc. Strong sound insulation effect. Compared with PVB film, EVA film has stronger sound insulation effect, especially for high-frequency sound. Due to various excellent properties, EVA film is widely used in current components and various optical products, especially playing an important role in the packaging of solar photovoltaic modules.Solar photovoltaic module packaging, EVA film is used to fix solar cells and provide insulation protection, optical coupling, and provide moderate mechanical strength and heat conduction paths. In recent years, with the rise and development of the global photovoltaic industry, the market demand for EVA has increased year by year, which has broad market prospects. There is also great room for improvement in the domestic EVA film market. Website: www.elephchem.com Whatsapp: (+)86 13851435272 E-mail: admin@elephchem.com ElephChem Holding Limited, professional market expert in
PVA dissolution methods
PVA 1. Temperature rise dissolution method The temperature rise dissolution method is one of the most commonly used methods for dissolving PVA. Add PVA powder 2. Dissolution by auxiliary agent In addition to directly adding PVA to water for dissolution, the solubility and stability of PVA can also be improved by adding auxiliary agents. Common auxiliary agents include acetone, methanol, ethanol, phenol, etc. These auxiliary agents can form hydrogen bonds or other interaction forces with PVA, thereby improving solubility. The addition of auxiliary agents can also shorten the dissolution time of PVA. 3. Slow cooling and dissolution The slow cooling method is a special PVA dissolution method, which is suitable for the preparation of polymers, micro-nano particles, films, fibers and other materials. The basic principle of the slow cooling method is to add PVA powder into water, heat it to dissolve it, and then slowly cool it down to make the PVA molecules self-assemble to form nanoparticles, nanofibers or films. The slow cooling rate has an important influence on the self-assembly process of PVA. Generally speaking, the slower the slow cooling rate, the more complete the structure of the PVA self-assembly. The slow cooling method is mainly suitable for the preparation of micro-nano materials. 4. Gas phase dissolution The gas phase method is a relatively new PVA dissolution method. In this method, the PVA solid enters the atmosphere through the dissolution hopper. By controlling the temperature, pressure and atmosphere composition, the PVA solid is directly evaporated into gaseous molecules, and then transported to other equipment through a transmission pipe for reaction or solidification to form a corresponding block. Unlike the traditional dissolution method, the gas phase method can prevent the PVA molecules from being affected by water decomposition, thereby maintaining the integrity and quality of the material. Website: www.elephchem.com Whatsapp: (+)86 13851435272 E-mail: admin@elephchem.com ElephChem Holding Limited, professional market expert in Polyvinyl Alcohol
PVB interlayer film
PVB Safety glass produced using all-resin PVB film has superior optical properties, higher light transmittance and lower haze, making the finished glass more transparent. For example, if multiple layers of PVB are used to make laminated glass, the advantages of all-resin PVB will be It will be more obvious. Secondly, the yellowing value of the film is very low and the film is whiter, so that the finished glass will not turn yellow and is suitable for ultra-white laminated glass. The all-resin film is more durable and can withstand the sun and rain. It will not cause degumming, bubbles, aging and other undesirable phenomena after long-term use. PVB interlayer film is widely used in construction, automobile, photovoltaic and other industries. PVB interlayer films produced with special formulas are also widely used in aerospace, military and high-tech industries, such as aircraft, aerospace products, military instruments, solar cells and solar receivers. It is currently the best adhesive material for manufacturing laminated and safety glass in the world. It is also widely used in construction fields such as building curtain walls, tents, showcases, bank counters, prison viewing windows, steel furnace screens and various bulletproof glass. Website: www.elephchem.com Whatsapp: (+)86 13851435272 E-mail: admin@elephchem.com ElephChem Holding Limited, professional market expert in
The role of redispersible emulsion powder in dry mixed mortar
The redispersible emulsion powder is first physically mixed with other inorganic cementing materials (such as cement, hydrated lime, etc.) and various aggregates and additives to make dry mixed mortar. When the dry mixed mortar is mixed with water, under the action of hydrophilic protective colloid (polyvinyl alcohol Ceramic tile binder is the cement-based bonding material of ceramic tile, which can be used to paste natural stone such as ceramic tile, polished brick and granite. The addition of redispersible emulsion powder can extend the working time and adjust the time of the newly mixed mortar, improve the water retention performance and anti-hanging performance; Improve the bonding property, deformation resistance and aging resistance of hardened mortar. External wall insulation system has been applied in the field of the world, and its installation on the external wall of the building mainly saves the energy consumption of the building 40%-70%. Dry mix mortar modified with redispersing emulsion powder is used to bond polystyrene board to the wall while protecting the polystyrene board. For protective mortars as well as cement-based decorative mortars, polymer adhesive powder provides good adhesion, impact resistance, low water absorption and high flexibility even in harsh environments. After film formation, the emulsion and redispersed emulsion powder can form high tensile strength and bond strength on different materials, and they are combined with cement as the second binder in the mortar, and the cement and polymer play the corresponding special features respectively, so that the performance of the mortar can be improved. Even if the type of emulsion powder copolymer is the same, due to the different production processes of different manufacturers, the properties of latex powder are different, and its properties in the corresponding mortar should be considered comprehensively when selecting rubber powder. With the increase of the national promotion of the use of dry mixed mortar, the demand for redispersible emulsion powder is showing a rapid growth momentum, which is bound to usher in a new peak of use. Website: www.elephchem.com Whatsapp: (+)86 13851435272 E-mail: admin@elephchem.com ElephChem Holding Limited, professional market expert in