Ethylene-Vinyl Alcohol Copolymer

In today’s hyper-competitive food industry, packaging is no longer just a container—it is a critical element of product preservation. With consumers demanding fewer artificial preservatives and longer shelf lives, food brands face a massive technical challenge: keeping oxygen out without adding unnecessary weight or bulk. Enter EVOH (Ethylene-Vinyl Alcohol Copolymer). This high-performance thermoplastic has rapidly become the gold standard for high-barrier food packaging, shielding sensitive products from spoilage, flavor loss, and degradation throughout the global supply chain.   1.What Exactly is EVOH? At its core, EVOH is a random copolymer of ethylene and vinyl alcohol. To understand why it works so well, we have to look closely at its molecular architecture: The Vinyl Alcohol Units: These segments feature highly polar hydroxyl (-OH) groups. They create an incredibly dense intermolecular hydrogen bond network that acts as a tight molecular mesh. This structure makes it almost impossible for small gas molecules like oxygen (O2), carbon dioxide (CO2), and nitrogen (N2), as well as volatile organic compounds (VOCs) and aromas, to pass through. The Ethylene Units: While vinyl alcohol provides the barrier, it is inherently water-soluble and notoriously difficult to process. Adding ethylene units introduces excellent water resistance, mechanical flexibility, and thermoplastic processability, allowing the polymer to be extruded and thermoformed efficiently.   2. Decoding EVOH Grades: The Mol% Factor Not all EVOH is created equal. The material's performance is strictly governed by its Ethylene Content (expressed in Mol% or mole percent). When choosing an EVOH model for your packaging lines, selecting the right grade is critical to balancing barrier performance with processing requirements. EVOH Ethylene Content Key Characteristics & Performance Best Applications Low Ethylene (27 – 29 mol%)  Extreme gas barrier efficiency due to high monoclinic crystallinity. Highly sensitive to humidity. Ultra-long shelf-life products, dry goods, and specialized industrial chemical packaging. Standard Grade (32-35 mol%)  (Kuraray EVAL F101B) The industry "sweet spot." Delivers an excellent balance of gas barrier property, thermal stability, and ease of extrusion. Chilled meats, dairy products, processed foods, and multi-layer squeeze bottles. High Ethylene (38 – 48 mol%) (EVAL H171B) Excellent stretchability, lower melting point, and superior resistance to moisture, though the gas barrier drops slightly. Deep-draw thermoforming, skin packaging, and high-stretch flexible films.   3. The Multilayer Powerhouse: Integrating Other Polymers Because EVOH is inherently hydrophilic (it absorbs water, which can temporarily weaken its gas barrier), it is rarely used as a standalone film. Instead, it is engineered into high-tech, multi-layer co-extruded structures—often totaling 5, 7, or 9 layers—where a microscopic layer of EVOH (frequently under 10 microns) is shielded by other performance polymers. A typical high-barrier co-extrusion stack includes: Structural Outer/Inner Layers (PP or PE): Polypropylene (PP) or Polyethylene (PE) layers provide moisture protection, structural integrity, and excellent heat-sealing capabilities. PP is ideal for high-temperature retort applications, while PE delivers superior flexibility for frozen foods. The Invisible Bond (Tie Resins): Because EVOH is highly polar and polyolefins like PP/PE are non-polar, they naturally repel each other. To prevent delamination, chemical manufacturers utilize Tie Layer Resins—typically Maleic Anhydride Modified Polyolefins (such as Admer or Bynel). These act as a molecular bridge, permanently anchoring the EVOH core to the structural layers. The Eco-Friendly Alternative to PVDC: Historically, PVDC (Polyvinylidene Chloride) was a dominant barrier material. However, because PVDC contains chlorine, it releases hazardous dioxins during incineration and complicates recycling. EVOH contains only carbon, hydrogen, and oxygen, making it a much safer, chlorine-free alternative for modern sustainable brands.   4. PP vs. EVOH: Understanding the Synergy A common question in packaging procurement is whether to use PP or EVOH. The reality is that they are partners rather than competitors. Feature Polypropylene (PP) EVOH Copolymer Primary Role Structural integrity, moisture barrier, heat-sealing. Gas barrier (Oxygen, Aromas, VOCs). Oxygen Barrier Relatively low. Exceptionally high (keeps $O_2$ out). Moisture Barrier High (protects against water vapor). Sensitive to moisture if unprotected. Chemical Resistance Excellent against acids, fats, and oils. High resistance to organic solvents and mineral oils. Cost Profile Economical commodity polymer. Premium specialty resin (used sparingly).   By combining them—using PP for the tough outer armor and a sliver of EVOH for the inner oxygen shield—manufacturers achieve a high-performance, cost-effective structure.     5. Economic & Environmental Benefits Deploying EVOH multi-layer technology yields significant bottom-line and environmental advantages: "Less Material, More Function": Because EVOH provides an exceptional barrier at a thickness of only a few microns, it enables radical down-gauging (light-weighting). This reduces raw material consumption and lowers shipping costs. Anti-Static & Pristine Display: EVOH exhibits natural anti-static properties. When integrated near the surface layer, it prevents dust accumulation on retail shelves, ensuring a glossy, crystal-clear, high-transparency package presentation that attracts buyers. A Massive Reduction in Food Waste: By eliminating oxygen permeation, EVOH dramatically delays oxidation, color loss, and spoilage without requiring heavily added artificial preservatives. Choosing the ideal EVOH grade and multi-layer structure depends entirely on your product's specific lifecycle—whether it requires deep-draw thermoforming, high-temperature sterilization, or extended ambient storage. By integrating targeted EVOH copolymers with standard polyolefins, modern packaging systems achieve an ideal balance of durability, cost efficiency, and world-class freshness preservation.   Website: www.elephchem.com whatsapp: (+)86 13851435272 E-mail: admin@elephchem.com

EVASIN EVOH resin is an ethylene-vinyl alcohol copolymer, used to manufacture films, sheets, and packaging containers with high oxygen barrier properties. The EVASIN series offers various grades of composition and rheological properties suitable for various processing techniques, such as multilayer co-extrusion, casting, blow molding, sheet molding, blow molding, biaxial stretching, injection molding, and extrusion molding. The ethylene content of EVASIN EVOH resin is related to its barrier properties; lower ethylene content results in higher oxygen barrier properties, and higher barrier properties lead to higher resin hardness. EVASIN EVOH (EVOH EW-3201) has excellent gas barrier properties, blocking various odors from seasonings, spices, cosmetics, etc., making it suitable for food packaging. It also exhibits excellent oil resistance and barrier properties against oils and chemical solvents, thus finding applications in automotive fuel tanks, pesticide bottles, and underfloor heating pipes. Characteristics: Excellent gas barrier properties, affected by humidity Good printability Oil resistance Solvent resistance Weather resistance High transparency High rigidity Excellent flexibility Good antistatic properties Moisture retention Good surface gloss   EVASINT EVOH Naming Principles: The letters E and V represent EVOH. The third and fourth digits represent the ethylene content: for example, 32 represents 32% ethylene content; 38 represents 38% ethylene content; 44 represents 44% ethylene content. The fifth and sixth digits are related to fat melting: 01 represents fat melting of 1-2 G/min, 51 represents a new specification with unchanged fat melting (190℃, 2160 G). The letter V represents: no processing aids added. The letter F represents: compounding processing aids added. EVOH has excellent barrier properties against gases such as oxygen, nitrogen, and carbon dioxide, but due to its hydrophilic groups, it has poor barrier properties against water vapor. Therefore, when considering barrier properties against all gases, EVOH is generally used as an intermediate layer in co-extrusion molding with traditional hydrophobic thermoplastics.     EVASIN EV-4405F is mainly used in the following fields: Packaging: Food Packaging: It is used as an intermediate barrier layer in composite films for aseptic packaging, hot cans, and retort pouches, packaging dairy products, meat, canned juice, and condiments. It effectively prevents oxygen and moisture from entering the packaging, extending the shelf life of food and maintaining its flavor and quality. For example, in milk powder packaging, it prevents the milk powder from getting damp and oxidizing, ensuring that the nutritional components of the milk powder are not destroyed. Non-food packaging: Used for packaging solvents, chemicals, air conditioning structural components, gasoline drum liners, electronic components, etc. Due to its excellent barrier properties, it can prevent solvent evaporation, chemical leakage, and protect electronic components from external environmental influences. Automotive industry: Due to its good oil resistance and barrier properties, it can be used as a barrier layer material for automobile fuel tanks, effectively preventing fuel evaporation and leakage, reducing environmental pollution, and improving vehicle safety and fuel efficiency. Other fields: It can be used to produce packaging materials for household goods, underfloor heating pipes, wallpaper, etc. In household goods packaging, it provides good protection and barrier properties; in underfloor heating pipes, it helps improve the pipes' corrosion resistance and oxygen barrier properties, extending the pipes' service life; in wallpaper, it can enhance the wallpaper's performance, such as waterproofing, moisture resistance, and odor blocking.   Website: www.elephchem.com whatsapp: (+)86 13851435272 E-mail: admin@elephchem.com

Ethylene-VinylAlcohol Copolymer (EVOH) resin provides a superior barrier against oxygen permeation, exhibiting performance up to four orders of magnitude greater than conventional polyethylene. Due to its excellent barrier properties, formability, and environmental friendliness, it is widely used in high-end new material fields such as automotive fuel tanks, films, food containers, and underfloor heating pipes. When it comes to food packaging, EVOH really helps keep food fresh and flavorful for a long time, sometimes even years, without needing preservatives. EVOH( EW-3201&EVAL F105B)is made bycombining ethylene and vinyl alcohol.     Applications    1.Packaging EVOH is often used with other materials for packaging since it's such a strong barrier: Food & Beverage: It’s used for items like milk, juice, seafood, and other things that spoil quickly. For example, Chinese seafood exporters use five-layer vacuum-sealed films made of PE, EVOH, and PA. Non-Food: You’ll find it in chemicals, cosmetics, pharmaceuticals, and electronics packaging.   2. Automotive Fuel Tanks: EVOH mixed with HDPE makes lightweight and affordable plastic fuel tanks. Structure : Outer layer (HDPE) → Recycled layer → Adhesive layer (LLDPE) → Barrier layer (EVOH) → Adhesive layer (LLDPE) → Inner layer (HDPE). Fuel Lines: PA-EVOH composite tubes replace metal pipes, aiding vehicle lightweighting.       3. Medical Selective Permeable Membranes: Sterilized via radiation (e.g., EVOH hollow fibers for dialysis). Artificial Kidneys: Hollow-fiber membranes for blood purification. Drug Delivery: EVOH-coated polymers for controlled-release medications. Biomedical Implants: Blends with corn starch or cellulose acetate for bone substitutes and tissue repair.   4. Construction Heating Pipes: EVOH’s oxygen barrier prevents corrosion in heating systems. Types: 3-layer (external barrier) and 5-layer (internal barrier) pipes, both using EVOH.   5. Other Uses Textiles: Heat-sealing adhesives with superior wash resistance for apparel. Hydrogen Storage: EVOH-modified hydrogen tank liners maintain elasticity and barrier performance even at low temperatures.   Website: www.elephchem.com Whatsapp: (+)86 13851435272 E-mail: admin@elephchem.com