ethylene vinyl acetate (EVA)

What is ethylene vinyl acetate (EVA)? The ethylene vinyl acetate (EVA) is a copolymer obtained by the polymerization of ethylene and vinyl acetate, usually containing between 10 and 50% vinyl acetate. This material has elastomeric properties and is soft, flexible, transparent, and resistant to cold and UV radiation. EVA is used as a safe alternative to PVC in various industries.

The ethylene vinyl acetate has properties such as softness and flexibility similar to rubber. It also has high transparency and gloss, resistance to stress fracture, low temperature resistance, water resistance, and stability against ultraviolet (UV) radiation. It is odorless or has a faint vinegar odor, is non-toxic, and lightweight.

The ethylene vinyl acetate copolymer with a low vinyl acetate content (up to about 4%) is known as vinyl acetate modified polyethylene. It is processed as a thermoplastic and has a higher gloss, softness, and flexibility than regular polyethylene. It is often considered non-toxic and safe.

In answer to the question, what is eva material, the moderate vinyl acetate content (about 4 to 30%) is known as a thermoplastic copolymer and is classified as a thermoplastic elastomer. As the percentage of vinyl acetate increases, the ethylene vinyl acetate properties exhibit similar properties to eva plastic or plasticized polyvinyl chloride. These materials, whether filled or pure, have good resistance to low temperatures. Samples with about 11% vinyl acetate are commonly used in the production of hot-melt adhesives.

In answer to the question, is eva rubber or plastic, it should be said that the EVA with a high vinyl acetate content (over 60%), known as EVA rubber. It has high elasticity, high flexibility, and behavior similar to natural rubber. It has good resistance to impact, cracking, and low temperatures, and is used for specialized applications.

The ethylene vinyl acetate material is produced by chain-growth polymerization of the monomers ethylene and vinyl acetate. For this process, various techniques are used, such as solution, suspension, bulk, and emulsion polymerization. The choice of the appropriate method depends on the desired final properties of the polymer and the process conditions.

One of the common methods for producing EVA is high-pressure bulk polymerization. This method uses tubular reactors or autoclaves. This process allows the production of polymers with desirable eva material properties and better control over the chain structure, and has wide application in industry.

Another method for ethylene vinyl acetate production is to use precise control of reaction parameters and process kinetics. This reaction, which is exothermic, is usually carried out in the presence of solvents such as methanol and initiators such as azo compounds or peroxides. The reaction temperature is controlled between 40 and 80 °C, and due to viscosity management, the conversion rate usually does not exceed 60%. The polymerization process consists of four main steps: initiation, growth, transfer, and chain termination, which affect the degree of polymerization, average molecular weight, and dispersion of the final polymer.

The ethylene vinyl acetate (EVA) exhibits excellent chemical stability, making it suitable for various applications where long-term durability is required. It demonstrates good resistance to many chemicals, including acids, bases, and ultraviolet (UV) radiation, which contributes to its stability in outdoor and industrial environments. A notable chemical reaction involving EVA is the hydrolysis of its vinyl acetate groups. When exposed to water and a catalyst under specific conditions, this reaction produces ethylene-vinyl alcohol (EVOH) and acetic acid. EVOH is valued for its superior barrier properties, enhancing EVA’s functional range.

Applications of ethylene vinyl acetate in follow-up manufacturing include:

• Hot melt adhesive, usually with additives such as waxes and resins to improve performance.
• An adhesion promoter in plastic wrap.
• In packaging, textiles, and bookbinding for bonding plastic films, metal surfaces, and coated papers.
• A powder in cementitious mortars and coatings.
• As a flexible sealant in packaging, with good low-temperature resistance.

Applications of eva materials as foam rubber include:

• Protective pads are used in sports equipment such as ski boots, bicycle saddles, hockey pads, boxing gloves, helmets, and water sports shoes.
• Shock absorbers in sports ethylene-vinyl acetate shoes increase comfort and reduce pressure.
• Use in yoga and exercise mats, and puzzle flooring.
• Production of slippers and sandals is due to their lightweight, high ductility, odorlessness, glossy appearance, and reasonable price.
• ethylene vinyl acetate foam sheets for crafts and children’s foam stickers.
• They are used in making artificial flowers due to their softness and flexibility.
• Use in automotive flooring and lightweight, flexible, and durable foams.

• The ethylene vinyl acetate is used as a drug carrier. The polymer is dissolved with the drug and fillers, molded, and then freeze-dried to provide controlled release. EVA does not degrade in the body and is highly stable.
• The ethylene-vinyl acetate is used in transdermal nicotine patches as a base for controlled release of nicotine through the skin.
• It is used in the manufacture of custom dental appliances due to its high flexibility and malleability.

Here is a summarized table of ethylene vinyl acetate uses in various industries:

The eva polymer is increasingly used in niche and emerging areas due to its versatility. In cosplay communities, it is favored for making costumes and props thanks to its ease of cutting, shaping, and painting, along with comfort and durability. Additionally, EVA is utilized in orthotic insoles, surfboard and skimboard traction pads, and in crafting realistic artificial flowers for decorative purposes.

The ethylene vinyl acetate is considered a safer alternative to polyvinyl chloride (PVC) because it is chlorine-free. This makes it more environmentally friendly and reduces the risks associated with the release of chlorinated compounds. As of 2014, organizations such as NTP (US National Toxicology Program), ACGIH (American Conference of Governmental Industrial Hygienists), IARC (International Agency for Research on Cancer), and OSHA (US Occupational Safety and Health Administration) have not identified EVA as a carcinogen. They have not reported any specific adverse effects on human health.

Like many plastics, ethylene-vinyl acetate has low biodegradability. One study has shown that it may have negative effects on some organisms, but no clear effects on human health have been reported so far. However, more detailed, long-term studies are still needed.

• resistance to cracks
• Flexibility in both mild and chilly weather
• Simple processing utilizing rubber and thermoplastic processing methods
• Adaptability
• the superior strength of the heat seal

Capability to Recycle

Although EVA is more difficult to recycle than specific other polymers, initiatives are being made to enhance end-of-life handling. While some EVA materials are being investigated for chemical recycling techniques, others can be recycled mechanically.

Biodegradable Substitutes

Current research aims to create biodegradable substitutes for conventional EVA by adding natural components or changing the polymer’s structure to make it more environmentally friendly.

Efficiency in Energy Use

One of EVA’s key environmental advantages is its energy efficiency. Compared to certain other polymers, EVA requires relatively low processing temperatures during manufacture and fabrication. This saves energy and reduces the carbon impact of products made using EVA.

SHOBEIR SHIMI Company, established in 2004 in Tehran, is a leading company in the field of import, export, and distribution of polymer and chemical raw materials. The company specializes in supplying products such as low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), polyvinyl chloride (PVC), polystyrene, compounds, masterbatches, and titanium dioxide pigments. Shabir Chemical Company provides consulting services and fast supply of goods by utilizing a specialized team and extensive relationships with domestic and foreign manufacturers. The company also plays an active role in exporting petrochemical products and is one of the key players in the domestic and international markets by focusing on quality, competitive prices, and after-sales support.

The ethylene vinyl acetate is produced and supplied in various forms and grades, each with specific properties and applications depending on the ratio of monomers and production conditions. The following are the common eva material definitions about forms and grades:

Physical forms of EVA:

• Pellets: The most common form of supply is suitable for extrusion processes, injection molding, and foam production.
• Fine and free-flowing powder: Suitable for mixing with solid additives, redispersible in water as an emulsion.
• Water-based emulsion: For coating applications, adhesives, and paint formulations.

EVA grades based on ethylene and vinyl acetate percentage:

The Shobeir Shimi Company has provided several solutions for requesting quotes for ethylene vinyl acetate to customers:

1. Call 021 71762 or 09121182057 to speak directly with the sales department.
2. Sending an Official email to info@shobeirshimi.com to receive the price file and suitable purchase conditions.
3. An online inquiry form to fill out the “Register Purchase Request” form and receive wholesale prices.
4. WhatsApp chat/application for quick communication with the sales department and the possibility of instant price inquiries.

Ethylene Vinyl Acetate (EVA) is a highly versatile copolymer, valued for its unique combination of properties including softness, flexibility, transparency, and resistance to UV radiation and low temperatures. As a non-toxic, odorless, and lightweight material, it serves as a safe alternative to PVC in various industries. The key to EVA’s adaptability lies in its customizable nature, as altering the vinyl acetate content allows it to be engineered into different grades—from a more rigid, polyethylene-like material to a highly flexible, rubber-like substance. This enables its widespread use in a remarkable range of products, including hot-melt adhesives, foam padding for sports equipment and footwear, and specialized industrial applications like solar cell encapsulation and air filters. While generally considered safe, with no reported adverse human health effects by major organizations as of 2014, its low biodegradability remains a concern that underscores the need for continued research. As a material that provides solutions across packaging, biomedical, and industrial fields, EVA’s unique blend of physical properties and safety make it an indispensable polymer for modern manufacturing.