| HS Code | 208252 |
| Product Name | Resyn 4302 |
| Chemical Composition | Vinyl acetate-ethylene (VAE) copolymer emulsion |
| Appearance | Milky white liquid |
| Solids Content | 55% by weight |
| Viscosity | 1800-2800 cP (Brookfield, 25°C) |
| Ph | 4.5-5.5 |
| Density | 1.06 g/cm³ |
| Glass Transition Temperature | -5°C |
| Minimum Film Formation Temperature | 0°C |
| Particle Size | 0.2-0.5 μm |
| Stabilizer | Polyvinyl alcohol |
| Freeze Thaw Stability | Stable up to 3 cycles |
As an accredited Resyn 4302 factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Resyn 4302 is packaged as a solid resin in 50 lb (22.7 kg) polyethylene-lined multi-wall paper bags, palletized. |
| Container Loading (20′ FCL) | Resyn 4302 is loaded into a 20′ FCL on pallets, securely braced, with proper labeling and ventilation for safe transport. |
| Shipping | Resyn 4302 is a polymer emulsion shipped in sealed drums, totes, or bulk containers. Protect from freezing and excessive heat, as temperature extremes can destabilize the product. Use dry, clean equipment for transfer. Ensure secure loading and upright positioning during transport to prevent leakage. |
| Storage | Store Resyn 4302 in its original, tightly sealed container in a cool, dry, well-ventilated area away from direct sunlight, heat, sparks, and incompatible oxidizers. Protect from freezing; ideal temperature is 40–90°F. Avoid contamination. If separation occurs, gently stir before use. Follow label shelf-life and disposal guidelines. |
| Shelf Life | Store unopened in a cool, dry place. Shelf life is 12 months from date of manufacture when stored properly. |
| Condition | ASTM D905 Shear Strength on Hard Maple | Failure Mode |
|---|---|---|
| 1 h after pressing | 1.8–2.5 MPa | Adhesive |
| 24 h at 23°C/50% RH | 7.0–9.0 MPa | Mixed adhesive/fiber |
| 7 days at 23°C/50% RH | 10.0–14.0 MPa | Wood fiber |
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Resyn 4302 is supplied as a polyvinyl-alcohol-stabilized vinyl acetate–ethylene copolymer dispersion with a nominal solids fraction of 54–56% as measured by ISO 3251. The ethylene comonomer content is not required on the certificate of analysis, but its effect appears as a glass transition temperature of approximately 0 °C under ISO 11357-2. That thermal midpoint separates the grade from unplasticized PVAc homopolymers, which commonly exhibit a glass transition near 33 °C and therefore require external plasticizers or coalescing solvents for continuous film formation below 20 °C. The ready-to-use dispersion has a pH of 4.0–5.0 per ISO 976 and a Brookfield viscosity of 2,000–4,000 mPa·s at 25 °C using spindle 4 at 20 rpm under ISO 2555. The protective colloid yields a pseudoplastic flow profile; apparent viscosity falls below 500 mPa·s at 1,000 s⁻¹ under ISO 3219. This shear-thinning characteristic reduces roller spatter on high-speed laminators operating above 80 m/min but simultaneously limits the dry-film build achievable from a single gravure application. Compared with solvent-borne polyurethane adhesives, the product is non-flammable in the supplied form and does not require explosion-proof coating equipment.
| Parameter | Method | Typical batch range | Unit |
|---|---|---|---|
| Solids content | ISO 3251 | 54.0–56.0 | % by mass |
| pH | ISO 976 | 4.0–5.0 | — |
| Brookfield viscosity | ISO 2555, RVT, spindle 4, 20 rpm, 25 °C | 2,000–4,000 | mPa·s |
| Density | ISO 2811-1 | 1.06–1.09 | g/cm³ |
| Minimum film-forming temperature | ISO 2115 | 0–2 | °C |
| Glass transition temperature | ISO 11357-2 | 0 | °C |
| Residual vinyl acetate monomer | ISO 13741 | <0.1 | % by mass |
| Particle size D50 | ISO 13320 | 0.8–1.2 | µm |
Batch records over a 12-month production window show solids variation of ±0.5% and pH drift of less than 0.2 units when stored in sealed totes at 15–30 °C. Particle-size distribution remains monomodal, with the D50 falling between 0.8 µm and 1.2 µm under ISO 13320; the D90 does not exceed 2.5 µm. This envelope is broader than that of film-forming acrylic emulsions because larger particles reduce penetration into uncoated kraft and corrugating medium.
Viscosity recovery after high-shear exposure is rapid but incomplete; after a 60 s cycle at 1,000 s⁻¹, Brookfield viscosity recovers to 90–95% of the initial value within 5 min. On gravure coating stations, the doctor blade gap must be compensated for this thixotropic lag. Machines set to a 6 mm gap for acrylic formulations typically require a reduction of 0.5–1.0 mm to prevent over-application of Resyn 4302.
In high-speed paper-to-paper lamination on a 120 m/min flat-sheet line with inline slitting, the grade is applied at 30–45 g/m² wet film weight. Wet-tack development begins after approximately 15 s open time at 23 °C and 50% relative humidity, reaching a green-bond strength of 2–3 N/25 mm at 60 s when tested by the tensile-peel procedure adapted from ASTM D903. The ethylene comonomer slows the drying-rate peak relative to PVAc homopolymers, extending the practical repositioning window on coated boards to 45–60 s, but also shifting the point of no-rebound later in the press cycle.
Film clarity after ambient drying is limited by the particle size. Haze measured on a 75 µm wet drawdown over glass is 8–15% under ISO 14782. This level is acceptable for packaging seams and envelope adhesives but should not be specified for clear-film lamination of polyester or polypropylene where haze below 5% is required.
Foaming was observed on a corrugated board laminator when the recirculation pump drew air at tank levels below 20%; the foam persisted for 30–45 s after landing in the receiving pan. This was attributed to the protective colloid and to the high application speed. Defoamer addition at 0.05–0.15% by weight, based on a mineral-oil/silica defoamer, eliminated the visible foam under the same tank conditions.
| Property | Resyn 4302 | Standard PVAc homopolymer | Acrylic emulsion |
|---|---|---|---|
| Tg under ISO 11357-2 | 0 °C | 33 °C | -20 to -40 °C |
| MFFT under ISO 2115 | 0–2 °C | 18–20 °C | <0 °C |
| Plasticizer demand for low-temperature film | none | 8–12% DBP or DIBP | none |
| Particle size D50 | 0.8–1.2 µm | 0.5–1.5 µm | 0.1–0.3 µm |
| Shore A hardness of dried film | 62–68 | 75–80 | 35–60 |
| Water resistance after 24 h soak | limited | moderate | good |
The principal difference is internal plasticization. In laminating adhesives formulated with a conventional PVAc homopolymer, addition of 8–12% dibutyl phthalate or diisobutyl phthalate is normally required to depress the minimum film-forming temperature below 10 °C. With Resyn 4302, low-temperature film formation is achieved without external plasticizer, which reduces mass-transfer losses from the bond line and lowers volatile organic content in the finished laminate. The trade-off is a softer final film: Shore A hardness of the dried polymer is typically 62–68, whereas an externally plasticized PVAc of equivalent MFFT may display 75–80. This softer film is advantageous for board laminations that are subsequently die-cut because edge cracking at the adhesive line decreases, but it is less suitable for rigid wood assembly where the adhesive must resist creep under sustained load.
Compared with acrylic emulsions of equivalent solids, Resyn 4302 has a substantially larger mean particle diameter. This characteristic is designed for porous substrates: it restricts capillary penetration into uncoated kraft and reduces adhesive strike-through by 30–50% relative to an acrylic with a 0.1–0.3 µm D50, based on penetration tests adapted from TAPPI T 530. On filmic backings, however, the larger particle size produces visible grain and lower wet-out. Corona-treated polyester below 38 mN/m surface energy is not reliably coated without a wetting agent; untreated polyolefin films are outside the practical adhesion range.
Within the same product family, lower-solids or higher-ethylene grades shift the glass transition downward and improve adhesion to nonpolar substrates. Homopolymer grades offer higher dry strength but require plasticizer for low-temperature film formation. Resyn 4302 is therefore positioned for ambient-forming packaging and laminating adhesives where plasticizer migration, fogging, and low-temperature film continuity are simultaneous concerns.
For indirect food-contact adhesive applications, the product may be formulated under FDA 21 CFR 175.105 when the end-use conditions meet that section. The as-supplied dispersion is normally below the heavy-metal thresholds referenced in RoHS Directive 2011/65/EU. As a water-borne material, its volatile organic content is typically below 20 g/L by EPA Method 24, which simplifies compliance in packaging and converting operations subject to regional VOC limits. Published data for specific high-temperature retort or microwave-susceptor constructions is limited.
Because the dispersion is stabilized by a protective colloid rather than a surfactant-only system, pH is not the sole determinant of colloidal stability; nevertheless, sustained storage below pH 4.0 produces slow hydrolysis of the vinyl acetate ester linkages. The result is an increase in acetic acid concentration of approximately 0.2–0.4% over 90 days at 35 °C, accompanied by a drop in Brookfield viscosity of 500–800 mPa·s. After 6 months, the dispersion may develop a perceptible vinegar-like odour and a visible sediment fraction of 1–2% by volume. Storage in stainless steel or lined steel totes is required; aluminum and unlined carbon steel are incompatible at this pH.
Acid-catalyzed crosslinkers such as blocked sulfonic acids must not reduce the compounded pH below 3.8. Below this boundary, pot life shortens to 24–48 h at 25 °C because the acid accelerates chain scission and destabilizes the polyvinyl alcohol protective layer. In a production batch for a side-seam adhesive on folding cartons, a pH adjustment to 3.5 with p-toluenesulfonic acid produced a viscosity increase of 400% within 36 h; the material was rejected before application. The preferred pH window for compounded formulations is 4.2–5.2.
Mechanical stability is adequate for diaphragm pumps and low-shear progressive cavity pumps. High-speed centrifugal pumps with tight clearances can generate localized shear above 10,000 s⁻¹, causing particle agglomeration and subsequent filter plugging on 100 µm screens. Production lines should use low-shear pumping and avoid throttling valves in recirculation loops.
Where the grade is used on coating lines without forced-air thermal drying, film formation at board surface temperatures of 4–8 °C remains continuous because the minimum film-forming temperature is 0–2 °C under ISO 2115. A small addition of a high-boiling coalescent such as 2–3% butyl diglycol based on wet dispersion is used only when the substrate is refrigerated below 4 °C; above that temperature the coalescent is unnecessary and increases blocking tendency in stacked sheets.
On an air-knife coater running at 40 m/min without dryer capacity, a dried adhesive layer of 18–22 g/m² required 36–42 g/m² wet application, with drying to a tack-free state requiring 20–25 min at 23 °C and 50% relative humidity. At 15 °C and 70% relative humidity, the tack-free time extended to 35–40 min, and silicone release liners showed blocking when stacked after 15 min. These conditions define the practical lower operating window for ambient coating; below 12 °C or above 70% relative humidity, forced-air drying or heated rolls are required.
Film specimens cast from Resyn 4302 and conditioned for 7 days at 23 °C and 50% relative humidity show a water uptake of 15–25% after 24 h immersion in distilled water at 23 °C, measured gravimetrically. The water whitening observed in the film is largely reversible during re-drying, but the tensile strength retention after wet exposure is typically 40–60% of the dry value. These results place the material in the water-resistant, but not water-proof, category. It is suitable for interior wood joints and packaging seams that experience intermittent moisture contact; it is not specified for exterior window assembly or structural laminates intended for continuous water immersion.
External crosslinkers are required when durable water resistance is needed. Addition of 3–5% polymethylol melamine or a blocked isocyanate dispersion on wet weight improves the 24 h water uptake to 8–12% and increases wet tensile retention to approximately 70%. However, the crosslinker addition also shortens pot life and raises the minimum film formation temperature by 1–2 °C. The compounded system must be evaluated for sprayability, and the coated stock should be dried above 60 °C for at least 2 min to activate the melamine reaction.
In nonwoven saturation of cellulose and polyester staple webs, Resyn 4302 is applied at 10–25% add-on by dry fibre weight. The larger particle size limits full interstitial penetration in tightly formed hydroentangled webs with basis weights above 80 g/m²; in such constructions the dispersion tends to deposit at the web surface, producing a surface film rather than a uniform through-structure binder. For high-loft air-laid webs, this surface deposition is beneficial because it increases stiffness at low add-on while leaving the core soft. The bound web exhibits tensile index values of 35–45 N·m/g when measured by the procedure of ISO 1924-2 after conditioning at 23 °C and 50% relative humidity.
Compatibility with wet-end additives is generally acceptable with nonionic surfactants and starch-based extenders; anionic acrylic thickeners may generate a viscosity increase of more than 1,000 mPa·s at 0.1% addition because of charge interaction with the polyvinyl alcohol colloid. Cationic fixing agents should be avoided unless their interaction is pre-tested in a 1 kg laboratory batch over 24 h, because immediate gelation has been observed at pH values above 5.0.
