Applications of USI Corporation UE631 EVA in Industrial Manufacturing

Our UE631 grade ethylene-vinyl acetate copolymer serves specialized functions in demanding industrial processes. Leveraging its controlled vinyl acetate content and consistent melt flow, manufacturers in select fields rely on its properties to meet technical, process, and regulatory requirements in advanced compound formulations and product engineering.

1. Photovoltaic Encapsulation Films

Photovoltaic module producers incorporate UE631 for encapsulation films thanks to its transparency, adhesive strength, and reliable crosslinking performance under lamination temperatures. This ensures encapsulant layers tightly bind silicon cells and backsheet materials, with long-term UV and humidity resistance essential for 25+ year field life. Its formulation enables consistent lamination cycles, reducing edge delamination and module failure rates while fulfilling rigorous electrical insulation and weathering criteria in solar installations. The copolymer’s melt viscosity profile allows precise sheet extrusion and calendering, ensuring uniform thickness across high-throughput module lines.

Industry compliance standards

• IEC 61215:2016 (Crystalline silicon terrestrial PV modules – Design qualification and type approval)
• UL 1703 (Flat-Plate Photovoltaic Modules and Panels)
• TUV Rheinland 2 PfG 1169/08.2007 (PV module safety)
• RoHS Directive 2011/65/EU (Restriction of Hazardous Substances in electrical and electronic equipment)

Typical usage ratio

• 65-75% as major matrix in PV encapsulant sheets, with ratio adjusted for glass/glass and glass/backsheet modules according to viscosity and crosslink density required

Downstream process integration

• Compounding with crosslinker and stabilizers before sheet extrusion
• Thermal lamination directly onto cell strings and glass substrate
• Post-lamination curing to lock in crosslinked structure

Final product types

• Solar module encapsulant film rolls
• Field-assembled crystalline and thin-film solar panels

2. Hot Melt Adhesive Formulation

UE631 sees heavy adoption in industrial hot melt adhesive (HMA) manufacture, specifically for packaging, woodworking, and hygiene goods assembly. Producers value its consistent viscosity and polarity, enabling strong initial tack and peel adhesion over a range of treated and untreated substrates. Customizable formulation with tackifiers and waxes tailors set time and polymer flexibility, while its thermal stability prolongs nozzle and process uptime in automated adhesive lines. Strict raw material QC eliminates gel formation or uneven flow during high-speed application, supporting repeatable bond strength even under variable plant climate conditions.

Industry compliance standards

• FDA 21 CFR 175.105 (Adhesives for indirect contact with food packaging)
• ISO 9001:2015 (Adhesive manufacturing quality system)
• REACH Regulation (EC) No 1907/2006

Typical usage ratio

• 25-50% polymer base in HMA, adjusted according to target open time, flexibility, and substrate compatibility

Downstream process integration

• Direct melt blending with resins, tackifiers, waxes in adhesive compounding reactors
• Granule or block casting for remelting, or direct drum packaging
• Application through slot die or spray nozzle during end-user assembly line operations

Final product types

• Hot melt glue sticks for packaging machines
• Case/carton closing adhesives for automated plants
• Disposable hygiene article assembly adhesives

3. Wire and Cable Flame-Retardant Compounds

Cable sheath compounders specify this copolymer as a matrix for halogen-free, flame-retardant wire insulation. Its compatibility with magnesium hydroxide and ATH fillers affords precise control of compound flexibility, ignition properties, and electrical resistivity. The inherent processability supports twin-screw compounding and extrusion at stable torque without filler agglomeration or breakdown. In cable jacketing lines, UE631 ensures compound melt consistency at high throughput, avoiding die build-up and maintaining smooth, void-free surface finishes. Manufacturers can reliably meet fire safety and smoke emission requirements in data, control, and building wire applications.

Industry compliance standards

• EN 50363-8 (Insulating, sheathing and bedding compounds for power cables)
• IEC 60332-1 (Cable flame propagation test)
• IEC 61034 (Measurement of smoke density of cables)
• RoHS 2011/65/EU

Typical usage ratio

• 18-30% in cable compound, modified based on flame retardant loader concentration, target flexibility, and local insulation thickness standards

Downstream process integration

• Melt compounding with mineral flame retardants and process aids
• Pelletizing and storage, followed by direct extrusion onto copper core or as outer jacket

Final product types

• Low-smoke zero-halogen (LSZH) wire insulation and jacketing
• Building and industrial control cables with enhanced fire safety

4. Flexible Foam for Footwear Midsoles

Leading footwear component manufacturers utilize this grade in injection-molded and compression-molded foam midsoles and outsoles. Its controlled vinyl acetate content imparts a balance of softness, resilience, and dimensional stability under repeated compression. Combined with chemical blowing agents and crosslinkers, the material consistently expands within closed molds to generate fine-cell structures required for cushioning and shock absorption. Batch control over melt strength and viscosity allows precise tuning for different shoe model requirements, reducing material waste and variation in final hardness across seasonal production cycles.

Industry compliance standards

• ISO 20344 (Test methods for footwear materials)
• ISO 9001:2015 (Certified QM for consistent foam performance)
• REACH Regulation (EC) No 1907/2006
• Restricted Substance Lists for major international footwear brands

Typical usage ratio

• 45-65% as principal polymer in foam compound, adjusted for desired density and recovery rate per shoe design

Downstream process integration

• Compounded with blowing agents, crosslinkers, fillers in intensive mixers
• Molding under temperature- and pressure-controlled cycles
• Post-mold curing and QA dimensional checks

Final product types

• Sports and casual shoe midsoles
• Slipper and sandal platforms

5. Packaging Films for Flexible Food Applications

Converters in flexible food packaging select this resin to enhance film impact strength, flexibility, and seal performance. The copolymer facilitates coextrusion with LDPE and LLDPE, producing multilayer films meeting modern shelf-life and machinability requirements for consumer goods. Its clean processability minimizes fish eyes and gel content in thin gauge films, ensuring optical transparency and seal integrity under fast horizontal packaging lines. The raw material purity supports compliance for direct contact with dry, moist, and oily food, aligning with global regulatory compliance in sensitive applications.

Industry compliance standards

• FDA 21 CFR 177.1350 (Ethylene-vinyl acetate copolymers in food contact films)
• EU Regulation No 10/2011 on plastic materials intended to come into contact with food
• China GB 9685-2016 (National Food Safety Standard for Additives in Food Contact Materials)

Typical usage ratio

• 7-18% blended as modifier with polyethylene base, tuned for required film toughness, clarity, and heat seal range

Downstream process integration

• Coextrusion with LDPE/LLDPE on blown or cast film lines
• Lamination with barrier or print substrates as needed
• Slitting and packaging into food wrap rolls or bag sheets

Final product types

• Resealable pouch films
• Vacuum packaging films
• Flexible film wraps for snacks, baked goods, and dairy

6. Toys and Childcare Article Molding

Producers of toys and baby care items specify this resin for soft, flexible, and phthalate-free components. Its molecular structure and strict control of extractables support safe skin and mouth contact in compliance with regulations across major markets. Efficiency in injection and blow molding enables high productivity without compromising finished part clarity or tactile softness. Technical teams rely on its low migration rates and purity, ensuring products meet both international toy safety directives and private label “no harmful substances” pledges required by global retailers.

Industry compliance standards

• EN 71-3:2019 (Migration of certain elements in toys)
• ASTM F963-17 (Standard Consumer Safety Specification for Toy Safety)
• ISO 8124 (International toy safety standard)
• EU 2009/48/EC (Toy Safety Directive)

Typical usage ratio

• 60-100% for single-material parts; lower blend ratios for co-molded overlays, depending on target hardness and flexibility

Downstream process integration

• Pellet drying and direct feeding to injection/blow molding lines
• Post-mold finishing (deburring, printing, assembly)
• Routine extractable and migration QC before shipment

Final product types

• Chewable teething rings and baby toy components
• Soft grip overlays for writing, art, or feeding utensils
• Infant bath and play articles