Dairen DA-265H Emulsão VAE

Dairen DA-265H is an aqueous vinyl acetate-ethylene (VAE) copolymer emulsion stabilized with a polyvinyl alcohol (PVOH) protective colloid system. The ethylene comonomer, incorporated at a level typical of high-flexibility VAE grades, permanently plasticizes the vinyl acetate backbone, yielding a film with a glass transition temperature (T_g) significantly lower than that of a comparable PVAc homopolymer. The dispersion is supplied at a nominal solids content of 54–56 % (ISO 3251) with a pH of 4.0–5.5 and a Brookfield viscosity (ISO 2555, RVT spindle 5/20 rpm at 23 °C) within the range specified on the manufacturer’s technical data sheet. The minimum film-forming temperature (MFFT, ISO 2115) is typically below 0 °C, permitting coalescence without high-boiling coalescing solvents in many formulations. DA-265H is designed for use in low-VOC interior architectural coatings, single-component construction adhesives, packaging lamination, carpet backing, and nonwoven binder applications where low-temperature flexibility and adhesion to non-polar substrates are required. The colloidal stabilization mechanism imparts shear stability suitable for high-speed pump transfer and roller-applied wet-end processes, with typical mean particle sizes falling between 0.8 and 1.5 µm as measured by laser diffraction (ISO 13320).

What Distinguishes DA-265H from Polyvinyl Acetate Homopolymer and Lower-Ethylene VAE Grades?

The incorporation of a high ethylene fraction modifies the copolymer backbone in several measurable ways that directly affect film properties and application performance. In homopolymer PVAc, the T_g resides near 30 °C, necessitating external plasticizers or coalescing agents to achieve film formation at ambient temperature. DA-265H, by virtue of internal plasticization, delivers dry film elongations exceeding 300 % and cold flexibility to below −15 °C. This ethylene modification also reduces the hydrophilicity of the acetate polymer, imparting improved water-whitening resistance and alkali resistance relative to homopolymer dispersions. The table below compares the characteristic property envelope of a high-ethylene VAE emulsion (DA-265H class) with that of a conventional PVAc homopolymer, using industry-standard test methodologies. Specific numerical values for DA-265H as produced in various plant campaigns are documented in the current lot-specific certificate of analysis available from Dairen Chemical Corporation.

In comparison with lower-ethylene VAE grades (those containing <10 wt% ethylene), DA-265H exhibits a markedly lower MFFT and greater flexibility at sub-zero temperatures, but its cohesive strength and heat resistance are correspondingly reduced. The practical consequence is that DA-265H is preferred in applications where substrate movement, thermal expansion mismatch, or end-use low-temperature exposure are dominant performance drivers, whereas lower-ethylene VAE emulsions are selected where higher modulus and elevated-temperature creep resistance are prioritized.

In pressure-sensitive adhesive coatings intended for removable labels and protective films, the high elongation and permanent tack of DA-265H films allow the adhesive to conform to low-energy surfaces without requiring aggressive adhesion promoters. Transfer coating onto siliconized release liner is performed using a comma bar coater at a wet film thickness of 50–100 µm, followed by three-zone forced-air oven drying with zone temperatures of 80, 110, and 120 °C. The dried film is then laminated to 50 µm corona-treated polyethylene at a nip pressure of 0.4 MPa. Production-scale trials on a 1.3 m wide pilot coater at line speeds of 40–80 m/min have been documented, showing that crosslinking with 0.3–1.0 phr aluminum acetylacetonate extends the holding power (shear adhesion failure temperature, PSTC-107) into the 80–100 °C range while retaining loop tack values on stainless steel (PSTC-16) exceeding 8 N/25 mm. Pot life of the compounded adhesive, determined as the time required for Brookfield viscosity to double at 23 °C, is typically 4–6 hours; applications using pre-heated transfer lines to reduce viscosity must thus balance throughput against progressive viscosity build. Incompatibility is observed with strong acid catalyst residues from certain tackifier dispersions; neutral or mildly alkaline hydrocarbon resins should be used to preserve colloidal stability.

Wood Adhesive Durability Classifications Under EN 204 and Processing Window Constraints

When compounded with reactive crosslinkers, DA-265H can be formulated into waterborne wood adhesives meeting the durability requirements of EN 204 classe D2 and D3 for interior non-structural and limited-humidity interior applications. A formulation comprising DA-265H, 5–15 phr glycidyl silane adhesion promoter, and 2–5 phr polymeric MDI has been shown to pass the 4-hour water soak test of EN 204 D3 when the bond is cured under a specific pressure of 1.0 MPa for 2 hours at 20 °C and subsequently conditioned for 7 days at 23 °C /50 % RH per EN 205. Full-scale production on a radio-frequency edge-gluer (operating at 3 kW, 27.12 MHz) achieved a set time of 15–20 seconds for 18 mm beech lamellae, with hot-press throughput constrained primarily by the moisture equilibration of the glued assembly. The processing window narrows considerably when ambient relative humidity exceeds 65 %: wood moisture content above 12 % retards bond strength development because water release into the substrate is impeded, and published data for this specific configuration is limited. Plant-scale experience indicates that when the equilibrium moisture content of the wood exceeds 14 %, a 24-hour clamping period should replace the standard 2-hour cycle to achieve equivalent shear strength. Substrate temperature during winter workshop conditions frequently falls below the 5 °C minimum film formation temperature of the uncrosslinked emulsion; in-line infrared pre-heating of the wood surface to 8–10 °C is recommended to ensure adequate wetting and coalescence. The adhesive is not suitable for full exterior exposure (EN 204 D4) and should not be used in direct contact with groundwater.

Historically, carpet tile manufacturing lines employing puddle coaters with a doctor bar at a gap of 0.8–1.5 mm have evaluated DA-265H as a replacement for styrene-butadiene rubber (SBR) latex in precoat and secondary backing applications. Tuft bind values, tested per ASTM D1335 on cut-pile nylon carpet, remain above 22 N when the precoat compound is loaded with 200–350 phr calcium carbonate (d₅₀ approx. 3 µm) and applied at a dry add-on of 180–220 g/m². Subsequent lamination of a polypropylene secondary backing using a 40–80 g/m² dry coating of DA-265H compound and routing through a 15 m convection oven at 130–145 °C for 3–5 minutes yields delamination strengths (ASTM D3936) exceeding 7 N/50 mm before accelerated aging. Compatibility with bitumen, PVC plastisol, and polyurethane foam secondary backings has been verified by 90° peel testing at ambient and after aging for 7 days at 70 °C in a forced-air oven per ASTM D3045. The colloidal stabilization of DA-265H is sensitive to filler grade and loading: when coarse calcium carbonate (d₅₀> 15 µm) is incorporated above 400 phr, high-shear compounding in a Cowles disperser operating at tip speeds greater than 15 m/s can initiate grit formation as the protective colloid is mechanically displaced from the emulsion surface. A laboratory-scale jar test following ASTM D869 for sedimentation and coagulum evaluation, using the specific filler lot sourced from the plant, is recommended before any scale-up campaign. Drying rate profiling on an actual line equipped with near-infrared moisture sensors demonstrated that residual moisture below 0.8 % at the wind-up station is required to prevent blocking in roll storage; this necessitates active control of line speed relative to oven temperature, particularly during humid summer conditions.

When Formulating a Coalescent-Free, Low-Odor Interior Wall Paint

The sub-zero MFFT of DA-265H eliminates the requirement for volatile coalescing solvents such as texanol or butyl carbitol, directly reducing initial paint VOC content to below 1 g/L in a flat formulation with a pigment volume concentration (PVC) of 65–78 %. Scrub resistance testing according to ASTM D2486 on a 200 µm wet film drawdown over sealed Morest chart paper indicates that DA-265H-based paints achieve 1000–1500 cycles before failure when the binder content is maintained above 12 wt% on total formula. Wet adhesion, evaluated per DIN EN 13300 using a 24-hour water immersion followed by a wet scrub brush, is characterized by complete film retention, whereas standard PVAc homopolymer paints typically exhibit cohesive failure within 100 cycles. In contrast to styrene-acrylic benchmarks, DA-265H films exhibit lower early water resistance; the coating is therefore specified for interior service under intermittent humidity, corresponding to ISO 13788 Class 2 conditions, and is not recommended for bathrooms, showers, or kitchen splash zones without a protective topcoat. Airless spray application trials employed a 0.015–0.017 inch reversible tip at 12–15 MPa fluid pressure with a 30-mesh in-line filter. Production batches prepared in 800 kg IBC totes and agitated with a slow-speed propeller mixer at 50–100 rpm showed no visible sedimentation for 72 hours. Interaction with associative thickeners of the hydrophobically modified ethoxylated urethane (HEUR) type must be accounted for: dosage of 0.3–0.6 % by weight on total formulation provides a mid-shear Stormer viscosity of 95–105 KU (ISO 2884-2), but over-addition beyond 0.8 % induces phase separation as the ethylene-rich binder segments interact with the thickener hydrophobes. Protect from freezing during transport and storage; one freeze-thaw cycle without 5 % added propylene glycol results in irreversible grit formation.

In high-loft nonwoven wiping cloth manufacture, DA-265H diluted to 15–20 % solids is applied via spray bonding in a Schott & Meissner through-air bonding line operating at 20–60 m/min. The dried web, consolidated at 135 °C for 40 seconds, exhibits machine-direction tensile strength per DIN EN 29073-3 in excess of 18 N/50 mm at a basis weight of 65 g/m² and a binder add-on of 20 %. The PVOH protective colloid imparts a degree of hydrophilicity that can be beneficial for cleaning applications but also leads to film swelling under continuous water immersion. Crosslinking with 1–2 % glyoxal on binder solids reduces water absorption by mass to 25–30 % after 1 hour soak, but increases the T_g of the film by approximately 8–12 °C, rendering the nonwoven brittle at −10 °C. Plant-scale correlation of infra-red dryer emitter temperature with residual moisture has shown that a surface temperature exceeding 150 °C at the dryer exit causes yellowing of the PVOH-stabilized film; the binder supplier’s maximum processing temperature guideline of 145 °C should be observed to maintain color integrity. The emulsion is not compatible with glyoxal-based crosslinkers that have dropped pH below 3.5 due to acid hydrolysis residues; premixing the crosslinker with a buffered deionized water stream to pH 6.0–7.0 before addition to the diluted emulsion avoids localized coagulation at the injection point.