Applications of Tosoh Nipoflex 631 EVA in Industrial Manufacturing

Tosoh Nipoflex 631 is an ethylene-vinyl acetate copolymer designed for demanding industrial conversion. As the direct manufacturer, we supply this grade for specific sectors requiring high flexibility, transparency, adhesion, and process consistency.

1. Solar Photovoltaic Encapsulant Film Manufacturing

Nipoflex 631 forms the primary resin in encapsulant films for photovoltaic modules. Its low gel level, narrow melt index window, and balanced VA content protect cells from moisture ingress and UV degradation during decades of outdoor exposure. Its technical profile ensures process stability during extrusion and lamination, and supports clear crosslinking in high-speed line manufacturing, where bubble formation or yellowing is not tolerated by Tier 1 cell assembly plants.

Industry compliance standards

• IEC 61215—Terrestrial PV Module Design Qualification
• UL 1703—Flat-plate Photovoltaic Modules and Panels
• RoHS 2011/65/EU—Restriction of Hazardous Substances
• REACH EC 1907/2006—Registration, Evaluation, Authorisation and Restriction of Chemicals

Typical usage ratio

• 95–99% by weight in direct extrusion, with the remainder being additives (crosslinking agents, UV stabilizers, anti-block agents)
• Ratio adjusted according to cell architecture and film thickness requirements

Downstream process integration

• Entrances at the film extrusion compounding phase, prior to cast or blown film line feeding
• Curing occurs in module lamination press at 140–155°C under vacuum
• Post-lamination, crosslinked film welds to cell glass and backsheet

Final product types

• PV encapsulant sheets (EVA sheets 0.45–0.7 mm thick)
• Solar cell modules (monocrystalline, polycrystalline, bifacial assemblies)
• Double-glass module encapsulant layers
• Back-contact module encapsulation

2. Hot Melt Adhesive (HMA) Base Resin for Packaging and Bookbinding

This grade functions as a critical backbone resin in industrial hot melt adhesives for food packaging and bookbinding. The 631’s melt flow property allows precise control in automated dosing systems, avoiding nozzle clogging and ensuring uniform laydown. The film-forming ability supports fast setting speeds as required by in-line carton forming or continuous spine gluing machines, helping packaging converters maintain throughput and avoid downtime.

Industry compliance standards

• FDA 21 CFR 175.105—Adhesives for Food Packaging
• BfR XXI—German Recommendations on Food Contact Materials
• ISO 9001—Quality Management Systems for Adhesive Manufacturing

Typical usage ratio

• 30–50% by weight in hot melt formulations
• Adjusted with waxes and tackifiers for open time and viscosity control according to end-use (corrugated, folding cartons, or hardcover books)

Downstream process integration

• Direct input at the compounding and melting stage
• Batch or continuous blending with functional additives before pelletizing or direct use in HMA tanks
• Applied by wheel, slot, or spray applicators at 160–180°C

Final product types

• Hot melt adhesive pellets or blocks
• Case and carton sealing adhesives
• Spine adhesives for bookbinding
• Paper and film lamination glues

3. Wire and Cable Insulation Compounds

In cable production, Nipoflex 631 acts as the major component in insulation and sheathing compounds. Its VA content supports both flexibility and good dielectric properties. The controlled melt viscosity minimizes scorch and die build-up during extrusion over copper or aluminum conductors, supporting reliable insulation for data, power, and automotive wiring.

Industry compliance standards

• UL 62—Flexible Cord and Fixture Wire
• IEC 60228—Conductor of Insulated Cables
• RoHS 2011/65/EU

Typical usage ratio

• 60–90% by weight as base polymer in insulation blends
• Modified with flame retardants, fillers, and process stabilizers as per burning and abrasion resistance requirements

Downstream process integration

• Melt blended with compounding additives after pre-mixing
• Extruded through crosshead dies onto moving wires at 130–160°C
• Passes through cooling, cutting, and printing stages upon insulation application

Final product types

• Flexible power cable insulation (low voltage)
• Automotive wire jacketing
• Instrument and appliance wire sheaths
• Data cable outer layers

4. Footwear Injection and Molding Compounds

The polymer is widely adopted by footwear manufacturers for injection and compression-molded shoe components, especially midsoles, outsoles, and insole boards. Its unique melt elasticity provides lightweight cushioning with high tear resistance. Processors can achieve fine expansion and closed-cell structure, meeting mechanical shock absorption and slip resistance targets, thus matching the needs of athletic and safety shoe OEMs.

Industry compliance standards

• EN ISO 20345—Safety Footwear Standards
• REACH EC 1907/2006
• GB/T 15107—Chinese Footwear Sole Specification

Typical usage ratio

• 70–100% by weight in direct injected foam soling compounds
• Blending with crosslinkers, blowing agents, and pigments as required, depending on hardness and expansion ratio needed

Downstream process integration

• Compounds loaded into single- or multi-station injection machines
• Foaming and curing inside metallic molds at 150–180°C
• Demolding followed by trimming and surface finishing

Final product types

• Sports shoe midsoles and outsoles
• Industrial safety shoe bases
• Sandals and flip-flop soles
• Custom orthopedic insoles

5. Flexible Film Production for Lamination and Printing

Converters employ Nipoflex 631 for producing clear and strong flexible films used in lamination and specialized printing applications. The resin’s clarity and drawability allow for both blown and cast film technologies. Its consistent gauge tolerance is essential for high-speed lamination with paperboard, foils, or barrier layers, meeting traceability demands of food and pharma pack converters.

Industry compliance standards

• FDA 21 CFR 177.1350—Ethylene-Vinyl Acetate Copolymers for Food Contact
• BfR XIV—Plastic Materials for Food Packaging
• EU 10/2011—Plastic Food Contact Materials Regulation
• ISO 22000—Food Safety Management Systems

Typical usage ratio

• 80–100% in single-layer films
• In multilayer coextrusion, 20–60% as tie or adhesion layer depending on laminate structure and end use

Downstream process integration

• Melting and extrusion into film in mono- or multilayer blown film lines
• Chilled roll or air ring quenching according to required thickness and mechanical properties
• Subsequent corona or flame treatment before downstream lamination and printing

Final product types

• Laminated snack food pouch films
• Medical device overwrap films
• Pharmaceutical strip pack films
• General-purpose flexible packaging substrates