Dairen DA-691 Emulsão VAE

In the field of waterborne polymer dispersions for interior architectural coatings, pressure-sensitive adhesives, and nonwoven binders, Dairen DA-691 occupies a distinct class of vinyl acetate–ethylene (VAE) emulsions with an ethylene content exceeding 20 wt%. The elevated ethylene incorporation, achieved via high-pressure emulsion polymerization, depresses the glass transition temperature (Tg) to approximately −18 °C and renders the minimum film formation temperature (MFFT) at or below 0 °C per ISO 2115. This intrinsic flexibility eliminates the requirement for external coalescing solvents or plasticizers, a functional advantage that permits formulators to achieve zero-VOC classifications under ASTM D3960 and ISO 11890-2. Manufactured by Dairen Chemical Corporation at facilities conforming to ISO 9001:2015 and ISO 14001:2015, DA-691 is stabilized with a surfactant system free of alkylphenol ethoxylates, thereby aligning with EU Directive 2003/53/EC and REACH Annex XVII restrictions. The dispersion’s dry film exhibits a permanent tack, high elongation at break, and a notable wet adhesion to alkaline substrates—a property profile that differentiates it from lower-ethylene VAEs such as DA-681 (MFFT 5 °C) and plasticized vinyl acetate homopolymers.

What physicochemical markers differentiate DA-691 from standard VAE dispersions?

The following properties are determined on a representative production batch and are controlled within batch-to-batch variation limits tighter than ±5 % relative.

Property	Nominal Value	Test Method
Total solids content	55.0 ± 1.0 %	ASTM D4758 (ISO 3251)
Brookfield viscosity (RVT, spindle 4, 20 rpm, 23 °C)	1800–3200 mPa·s	ISO 2555
pH at 25 °C	4.2–5.2	ASTM E70 (ISO 976)
MFFT (film-drawing bar, 200 μm wet)	0 °C	ISO 2115
Average particle size (laser diffraction, D50)	180–240 nm	ISO 2424
Glass transition temperature (DSC, midpoint)	–18 °C	ISO 11357-2
Surface tension (Du Noüy ring, 20 °C)	38–42 mN/m	ASTM D1331
Mechanical stability (Marón, 10 min at 75 % solids)	<0.5 % coagulum	ASTM D1417
Residual vinyl acetate monomer	<500 ppm	ISO 4901

The combination of sub-250 nm particle size and a medium anionic/nonionic surfactant package yields a shear-thinning rheology profile characterized by a flow index 0.50–0.65 (power-law model, 0.1–100 s⁻¹). This permits high-speed transfer without cavitation in progressing-cavity pumps when discharge pressures remain below 8 bar. The low residual monomer figure supports compliance with Ecolabel 2014/312/EU indoor paint criteria. In contrast, DA-681, with an ethylene content approximately 14–16 wt%, requires at least 1.5–2.5 % coalescent (based on total emulsion weight) to form coherent films below 8 °C, increasing the volatile organic content of the final formulation by 20–35 g/L. In high-speed lamination of paper and board at line speeds exceeding 150 m/min, DA-691 develops destructive substrate failure within 0.8 s of nip closing on clay-coated SBS board when applied at a coat weight of 18–22 g/m² dry. The wet tack correlates with a rapid dewatering rate driven by the emulsifier desorption mechanism; capillary penetration time reduction to <2.5 s on 60 g/m² kraft paper has been recorded via ultrasonic liquid penetration measurement. Laminates conditioned at 23 °C and 50 % RH for 24 h attain peel adhesion values of 5.5–7.0 N/cm on oriented polypropylene (surface energy> 38 mN/m, treated) when tested per ASTM D903. The absence of migratory plasticizer ensures that bond strength does not decay below 80 % of the initial value after 1000 h aging at 50 °C, a failure mode commonly observed in plasticized homopolymer formulations where dibutyl phthalate migration embrittles the interphase.

Adhesion to critical low-energy substrates — mechanical interlock versus surface-tension-driven wetting

On untreated polyethylene terephthalate films, the high ethylene content contributes to a contact angle below 55° within 3 s of application, measured via goniometer under ASTM D5946. Peel strength on corona discharge-treated LDPE (surface energy raised to 42 mN/m) exceeds 4.5 N/cm at a dry film thickness of 15 μm, whereas untreated LDPE (31 mN/m) yields cohesive failure in the adhesive at 0.8–1.2 N/cm, illustrating the critical threshold of substrate wetting. In comparison, styrene-acrylic copolymer emulsions of similar Tg often require an additional surfactant additive to reach equivalent wetting, which introduces foam and water sensitivity. The VAE structure imposes its own constraint: sustained temperature exposure above 70 °C under continuous load reveals a shear adhesion failure temperature (SAFT) of 62–68 °C (ASTM D4498, 1 kg static load), below that of lightly crosslinked acrylic systems, limiting its use in hot-fill label adhesives without post-crosslinking.

Parameter	Dairen DA-691	Dairen DA-681	Dairen DA-671
Ethylene content (approx.)	20–24 wt%	14–16 wt%	8–10 wt%
MFFT	0 °C	5 °C	10 °C
Tg	–18 °C	–8 °C	+5 °C
Typical coalescent demand (interior matte paint)	0–0.5 % on binder	2–3 %	4–6 %
Wet scrub resistance (flat paint, 55 % PVC)	1200–1800 cycles	800–1100 cycles	500–700 cycles
Set time (paper/board, 20 g/m²)	<2.5 s	3–4 s	4–6 s

The migration of ethylene into the vinyl acetate backbone at higher molar fractions permanently disrupts poly(vinyl acetate) crystallinity, which is reflected in the elongation at break of unpigmented DA-691 films measuring 850–1000 % (ISO 527-3, 500 mm/min), versus 450–600 % for DA-681. This elasticity underlies the selection of DA-691 as the binder in elastic nonwovens for disposable hygiene products, where CD elongation demands exceed 300 % retention after 24 h wet conditioning.

When the architectural specification demands Class 2 scrub resistance without alkylphenol ethoxylate surfactants

Flat through semi-gloss interior wall paints formulated with DA-691 at a pigment volume concentration (PVC) of 45–55 % and TiO₂ at 250–320 lbs per 100 gal achieve wet scrub resistance exceeding 1500 cycles per ASTM D2486 Method B, qualifying for MPI Detailed Performance Standard #53 (interior latex, flat). The critical PVC/CPVC shift in this system lies near 61 %; beyond this value, wet scrub loss accelerates from 0.8 mg/100 cycles to>3.0 mg/100 cycles due to void coalescence and loss of film integrity. The low MFFT eliminates the need for 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate or equivalent high-boiling coalescents, thereby allowing full compliance with the CDPH Standard Method v1.2 emission testing protocol for school and healthcare projects. Associative thickeners of the hydrophobically modified ethoxylated urethane (HEUR) type must be selected with mid-shear ICI viscosity targets of 1.2–1.6 P to maintain sag resistance above 12 mils wet without causing syneresis during storage. Published data for this specific grade in deep-tone bases at less than 5 % TiO₂ loading is limited, though industrial experience indicates rub-out resistance per ASTM D4827 remains within ΔE <1.0 units when tinted with 12 fl oz/gal universal colorant. For cementitious waterproofing slurries, the emulsion must maintain hydrolytic stability in an alkaline environment exceeding pH 12.5 for the duration of the pot life. DA-691, when incorporated into a two-component system with a polymer-to-cement ratio (p/c) of 0.18–0.22, increases the 28-day bond strength to concrete from 0.8 MPa (unmodified) to>2.5 MPa per ASTM C1583, while elongation at break under ASTM D412 reaches 28–35 %. The formulation must include a liquid defoamer based on polyether-siloxane chemistry dosed at 0.3–0.5 % on total liquid weight to prevent air-entrapment-induced pinholing through a 2 mm cured film. Water uptake after 48 h immersion under EN 14891 A.6 remains below 6 % by weight, a value achievable without additional hydrophobic admixtures, owing to the inherent water resistance of the ethylene-rich polymer backbone. Prolonged wet-dry cycling (>200 cycles) may induce surface chalking; therefore, top-coating with an acrylic sealer is recommended in exterior exposure.

Optimizing shelf life and pump transfer without compromising colloidal stability

Storage at temperatures below 5 °C risks ice crystal formation and coagulation; recovery after 3 freeze-thaw cycles per ASTM D7149 is not guaranteed and often results in granular sediment> 50 mL/kg (wet-sieve residue on 45 μm mesh). In plant transfer lines, progressive cavity pumps operating at pressures above 10 bar or centrifugal pumps generating localized shear rates> 15,000 s⁻¹ can cause a permanent viscosity drop of 15–30 % within 200 pass equivalents, as measured by a recirculation loop test. Pre-filtration through a 100 μm bag filter and the installation of pulsation dampeners reduce this risk. The dispersion is incompatible with amine-based pH adjusters at use levels exceeding 0.3 %, which cause a rapid irreversible gel formation through aluminum ion bridges when kaolin or bentonite thickeners are present. Regulatory status relevant to food contact indirect additive applications is documented under FDA 21 CFR § 175.105 (adhesives) and § 176.170 (components of paper and paperboard in contact with aqueous and fatty foods) when the finished adhesive layer is less than 0.1 mm and fully cured. For EU markets, a Declaration of Compliance under (EU) No 10/2011 for plastics intended to come into contact with food should be verified for the specific migration limits of sodium vinyl sulfonate or co-monomers that may be present at trace concentrations. DA-691 is not designed for outdoor clear-coat applications where UV-A and UV-B exposure induces rapid chain scission unless blended with at least 25 % acrylic latex carrying hindered amine light stabilizers.