EVA resin

EVA is the abbreviation for ethylene-vinyl acetate copolymer, a random copolymer composed of nonpolar, crystalline ethylene monomers and strongly polar, amorphous vinyl acetate monomers (also known as VA). It was first synthesized in 1928 by American scientist H.F. Mark using a low-pressure method. Later, in 1938, the British ICI Chemicals Company published a patent for high-pressure polymerization to manufacture EVA, and in the early 1960s, DuPont in the United States began producing industrial products. Today, its applications have permeated all aspects of people's lives, such as shoe materials, films, wires and cables, toys, hot melt adhesives, coatings, etc. 1 Synthesis Process The vinyl acetate (VA) content in ethylene-vinyl acetate copolymers can range widely, from 5% to 95%. Different contents result in different properties, therefore, strictly speaking, there are different subcategories, as shown in the figure below:   Classification of Ethylene-Vinyl Acetate Copolymers VA (Vinyl Acetate) Content, Mass Fraction Characteristics EVA Resin 5%~40% Solid resin appearance at room temperature (most commo VAE (Vinyl Acetate-Ethylene Copolymer) EVA Rubber 40%~80% Flexible and elastic   VAE Emulsion 70%~95% Emulsion state   However, the EVA products commonly referred to are EVA resins, with VA content generally ranging from 5% to 40%. Most EVA manufacturers produce this type, therefore, the EVA discussed below refers to EVA resin. Regarding the synthesis process of EVA, after more than 50 years of development, there are currently four main mature EVA production technologies both domestically and internationally: high-pressure continuous bulk polymerization, medium-pressure suspension polymerization, solution polymerization, and emulsion polymerization. Among these, solution polymerization and emulsion polymerization are less commonly used, with most companies employing the high-pressure continuous bulk polymerization process. Since the polymerization reaction mechanism of EVA under high pressure and high temperature is essentially the same as that of LDPE, the difference between EVA products produced using autoclave reactors and tubular reactors is similar to the difference between LDPE products produced using these two processes.   Comparison Items Tubular Method Station Method Molecular Weight Distribution Narrow Wide Branch Distribution Few and Irregular Many and Uniform Molecular Structure Few Long Branches Many Long Branches Properties Good Mechanical Strength Good Elasticity Foaming Performance Slightly Poor Slightly Superior Main Applications Thin Films Foaming,Coating,Fujibang Electronics   2 Structural Properties Compared to PE, EVA, due to the introduction of vinyl acetate monomers into the molecular chain, has reduced crystallinity, improved flexibility, impact resistance, and enhanced filler incorporation and heat-sealing properties. Its density is generally between 0.91 and 0.93, and it exhibits good transparency and gloss. The properties of EVA resin mainly depend on the vinyl acetate content (VA content) and melt flow rate (MFI) in the copolymer. With a constant MFI value, the changes in various properties as VA% increases are as follows:   Increased performance Decreased performance Density Strength Gloss Hardness Flexibility Heat distortion Stress cracking resistance Water resistance Low temperature resistance Sound insulation Oil resistance     Under the condition of constant VA% content, the effect of increasing MFI value on performance is as follows: Increased performance Decreased performance Flowability Molecular weight Surface gloss Mechanical properties   Environmental stress cracking resistance   Softening point   EVA products exhibit good flexibility, low-temperature resistance, impact strength, environmental stress cracking resistance, good optical properties, good air permeability, moderate mechanical properties, and poor insulation properties over a wide temperature range.   3 EVA Processing and Molding EVA is a thermoplastic polymer, therefore it can be used in injection molding, extrusion, blow molding, calendering, rotational molding, vacuum thermoforming, foaming, coating, heat sealing, welding, and other processing and molding processes. EVA has a low molding temperature range (160-200℃) and a wide range of temperatures. Its mold temperature is low (20-45℃), and the material must be dried before processing (drying temperature 65℃). During EVA processing, the mold temperature and material temperature should not be too high, otherwise the surface will be rough (not smooth). EVA products are prone to sticking to the front mold; it is better to make the cold slug well at the main runner of the sprue a pull-tab type. It is prone to decomposition at temperatures exceeding 250℃. EVA is best processed using "low temperature, medium pressure, and medium speed" conditions.   4 Application Areas EVA applications have permeated all aspects of people's lives, such as shoe materials, films, wires and cables, toys, hot melt adhesives, coatings, etc. Shoe Materials Shoe materials are the most important application area for EVA resin in my country. The vinyl acetate content in EVA resin used in shoe materials is generally between 15% and 22%. Because resin-blended foam products have properties such as softness, good elasticity, and chemical corrosion resistance, they are widely used in the soles and lining materials of mid-to-high-end hiking shoes, mountaineering shoes, slippers, and sandals; in addition, this material is also used in sound insulation boards, gymnastics mats, and sealing materials. EVA Film The main use of EVA film is in the production of functional greenhouse films. Functional greenhouse films have high weather resistance, anti-fogging properties, and heat insulation properties. Because polyethylene is non-polar, even with the addition of a certain amount of anti-fogging agent, its anti-fogging performance can only be maintained for about 2 months; while greenhouse films made with a certain amount of EVA resin not only have higher light transmittance but also significantly improved anti-fogging performance, generally exceeding 4 months. In addition, EVA can also be used to produce packaging films, medical films, laminated films, and cast films. Wires and Cables With the continuous development of computer and network engineering, and for the sake of computer room safety, halogen-free flame-retardant cables and silane cross-linked cables are increasingly used. Because EVA resin has good filler compatibility and cross-linking properties, it is widely used in halogen-free flame-retardant cables, semiconductor shielded cables, and two-step silane cross-linked cables. Furthermore, EVA resin is also used to make sheaths for some special cables. The vinyl acetate content of EVA resin used in wires and cables is generally between 12% and 24%. Toys EVA resin also has many applications in toys, such as children's wheels and seat cushions. In recent years, my country's toy processing industry has developed rapidly, with production concentrated in coastal areas such as Dongguan, Shenzhen, and Shantou, mainly for export and processing. Hot melt adhesives Primarily composed of EVA resin, are solvent-free, environmentally friendly, and highly safe, making them ideal for automated production lines. In recent years, they have widely replaced traditional phenyl adhesives and are therefore widely used in bookbinding, furniture edge banding, automotive and home appliance assembly, shoemaking, carpet coatings, and metal anti-corrosion coatings. Hot melt adhesives mainly use varieties with a vinyl acetate content of 25%-40%. Although domestic products of this brand exist, production has been largely absent, resulting in imports dominating the market. Photovoltaic Industry Currently, in the solar cell industry, EVA is used for bonding solar cells to the surface photovoltaic glass and the backsheet in crystalline silicon cells. Because EVA films possess excellent flexibility, optical transparency, and heat-sealing properties, they have become the preferred photovoltaic encapsulation material. With the rapid development of the Chinese photovoltaic market, the EVA solar cell encapsulation film market has also experienced rapid growth, attracting many companies to invest in and enter this market. However, this indiscriminate entry has led to overcapacity and price competition, resulting in the highly competitive solar anti-dumping measures. Coating Coating materials are mainly used for coating layers of PET film and BOPP film. Taking advantage of the transparency and adhesion of EVA, they are used for applications such as quick sealing of photos and sealing of clothing bags.   Website: www.elephchem.com whatsapp: (+)86 13851435272 E-mail: admin@elephchem.com

Hot melt adhesive is solvent-free, almost odorless, pollution-free, and easy to apply, so it is widely used in many fields. Hot melt adhesive with ethylene-vinyl acetate random copolymer (EVA) as the base resin is one of the most important varieties of hot melt adhesive, which can be used in packaging materials, book binding, wood processing and other industries.   The development of EVA hot melt adhesive in my country began in the early 1970s. In the 1980s, due to the rapid development of related industries and industries such as printing, food and beverage, wood processing, and electronics, various production lines were introduced to stimulate the rapid growth of new product development and production capacity of EVA hot melt adhesive. EVA hot melt adhesive is mainly used in the following fields in my country.   1 Book binding EVA hot melt adhesive is used for wireless binding, which changes the cumbersome processes of threading round backs, gluing, and covering the cover used in the past for binding books with latex, greatly shortening the book publishing cycle and improving work efficiency and book binding quality. 2 Wood processing In wood processing, EVA hot melt adhesive is mainly used in combination with panel furniture edge banding machines for furniture edge banding, which has changed the backward appearance of manual operation in the past, and is easy to fold and assemble, which improves labor efficiency. 3. Clothing lining EVA and EVAL powders are inexpensive and have good adhesion. They are suitable for various coating processes such as powder coating, powder dot coating, and slurry coating. The hot melt lining made of EVA hot melt adhesive can make the clothing beautiful, crisp, non-deformed, and low-cost. 4 Packaging The bonding ability of EVA hot melt adhesive is relatively stable, not affected by changes in temperature and humidity in the working environment, and eliminates the inherent gluing and peeling problems of packaging machinery. Therefore, EVA hot melt adhesive can be used in the packaging industry in the fields of cardboard and cardboard boxes, cement bags, labeling, food packaging, protective packaging, and packaging container sealing.   EVA hot melt adhesive is also used in the manufacture of electrical appliances such as televisions, air conditioners, refrigerators, as well as the shoemaking industry, PET blow molding bottles, cigarette filter winding, outer packaging tear strips, cable joint sealing, oil pipeline anti-corrosion and other fields.   Website: www.elephchem.com Whatsapp: (+)86 13851435272 E-mail: admin@elephchem.com   ElephChem Holding Limited, professional market expert in Polyvinyl Alcohol(PVA) and Vinyl Acetate–ethylene Copolymer Emulsion(VAE) with strong recognition and excellent plant facilities of international standards.

EVA( Ethylene Vinyl Acetate) resin is short for ethylene acetate-ethylene resin, which is a polymer made of ethylene acetate and ethylene monomer. According to the different contents of ethylene acetate, the copolymers of ethylene and ethylene acetate were divided into EVA resin, EVA rubber and VAE emulsion. .Products containing less than 40% vinyl acetate are EVA resins.    EVA resin has good softness and shock-absorbing properties. It is one of the materials widely used in the footwear manufacturing industry and can be used to make soles, insoles, uppers and other components. It is also often used as a cushioning material, such as knee pads, wrist pads, and ankle pads in sporting goods, as well as car seat pads, motorcycle seat pads, etc.   EVA resin can be molded through various processing methods, such as extrusion, injection, calendering, etc., and it also has shock-absorbing properties. It is an excellent packaging material such as protective film, liner, protective cover, etc. to protect items during transportation and storage. No damage is caused during the process.   The chemical resistance of EVA resin can resist the erosion of many chemical substances. In medicine, EVA resin is often used to make medical instruments and equipment, such as surgical instruments, medical tapes, gloves, etc. It has good chemical resistance and transparency, and meets hygiene and health requirements. It is also an insulating material for electronic products, such as cable insulation tubes, insulating gaskets, etc. It can also be used as a protective material for batteries, with excellent chemical resistance and heat insulation properties.   In terms of building materials, EVA resin can be used as building materials, such as sound insulation panels, heat insulation panels, etc. It has good sound absorption, heat insulation and weather resistance properties, and can improve the comfort of buildings.   Agricultural use EVA resin can be used as agricultural covering film. It has good weather resistance and light transmittance, and can protect crops from bad weather.   Website: www.elephchem.com Whatsapp: (+)86 13851435272 E-mail: admin@elephchem.com ElephChem Holding Limited, professional market expert in Polyvinyl Alcohol(PVA) and Vinyl Acetate–ethylene Copolymer Emulsion(VAE) with strong recognition and excellent plant facilities of international standards.

Ethylene Vinyl Acetate (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(V6110S) 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 Polyvinyl Alcohol(PVA) and Vinyl Acetate–ethylene Copolymer Emulsion(VAE) with strong recognition and excellent plant facilities of international standards.