Dairen DA-161 VAE Emulsion

Formulation	Test condition (EN 204 cycle)	Shear strength, MPa (EN 205)	Wood failure, %	Classification
DA-161 without crosslinker	24h cold water soak (20°C)	1.2–1.8	10–25	D2
DA-161 + 3.5% pMDI	4h boiling water + 20h drying + 2h boiling (D4)	4.8–5.5	80–95	D4
DA-161 + 3.5% pMDI	7day cold water soak (D3)	6.2–7.1	85–100	D3

Formulation

Test condition (EN 204 cycle)

Shear strength, MPa (EN 205)

Wood failure, %

Classification

DA-161 without crosslinker

24h cold water soak (20°C)

1.2–1.8

10–25

DA-161 + 3.5% pMDI

4h boiling water + 20h drying + 2h boiling (D4)

4.8–5.5

80–95

DA-161 + 3.5% pMDI

7day cold water soak (D3)

6.2–7.1

85–100

p/c ratio (by mass)	Compressive strength, MPa (EN 12190)	Flexural strength, MPa (EN 196-1)	Capillary absorption coefficient, kg/(m²·h⁰⁵) (EN 1015-18)	Adhesion to concrete, MPa (EN 14891)
0.05	45.2	6.8	0.52	0.8
0.10	34.7	9.1	0.18	1.4
0.15	19.8	11.2	0.06	1.9
0.20	11.6	10.5	0.02	1.6

p/c ratio (by mass)

Compressive strength, MPa (EN 12190)

Flexural strength, MPa (EN 196-1)

Capillary absorption coefficient, kg/(m²·h⁰⁵) (EN 1015-18)

Adhesion to concrete, MPa (EN 14891)

0.05

45.2

6.8

0.52

0.8

0.10

34.7

9.1

0.18

1.4

0.15

19.8

11.2

0.06

1.9

0.20

11.6

10.5

0.02

1.6

DA-161 wet tack development under near-instantaneous compression on rotary die-cut lines

On modern high-speed lamination lines running at 150–200 m/min, the emulsion’s ability to develop initial wet tack within 0.3–0.5 seconds after nip contact determines acceptable adhesion at the trim stations where paperboard, metallised polyester, or aluminium foil are bonded to lightweight recycled corrugate. DA-161 is diluted with demineralised water to 45–48% solids and delivered via a closed-chamber doctor blade system to a chrome-plated engraved roller with 60–80 lines/cm and 7–9 cm³/m² cell volume, resulting in a dry coat weight of 2.5–3.5 g/m². Wet tack build-up is governed by the coagulation rate upon contact with the porous cellulose substrate; pH of the diluted emulsion is adjusted to 5.0–5.5 using a citric acid buffer to accelerate dewatering without premature skin-over on the roller surface. Nip pressure is maintained at 18–22 N/cm of web width, and the composite web passes through a series of heated drying drums at 110–130°C surface temperature, achieving 97% of final peel strength within 2.5 seconds of heated contact. Terminal packaging products include luxury rigid box wraps, liquid aseptic brick overwraps, and pizza carton barrier laminates, all conforming to FDA 21 CFR 176.170 (components of paper and paperboard in contact with aqueous and fatty foods) and EU 10/2011 migration limits when total extractives are kept below 10 mg/dm². A documented production failure mode occurs when silicone-based paper release agents contaminate the substrate surface; even residual silicone at 0.01 mg/m² depresses wet tack to the point where peel-strength drop-off exceeds 40% within the first 10 minutes of ageing. Inline corona treatment at 1.5–2.0 kW is therefore mandated when converting silicone-coated backing papers.

A diluted DA-161 solution applied as a penetrating primer on concrete substrates resolves dusting and excessive porosity prior to tile adhesive or self-leveling underlayment installation. The emulsion is reduced with potable water at a volumetric ratio of 1:2 (emulsion to water) to achieve a solids content near 18%, then roller- or spray-applied in a single pass at 0.15–0.25 kg/m² wet. Penetration depth into a C25/C30 concrete substrate ranges from 2–5 mm depending on capillary pore structure, measured by dye tracer per EN 1504-2. After 2–3 hours drying at 20°C, the primed surface achieves a pull-off adhesion strength above 1.2 MPa when tested with a 50 mm diameter dolly per ISO 4624, with cohesive failure occurring in the substrate rather than at the primer interface. The primed layer also functions as a water-vapour-permeable barrier with an SD value below 0.3 m, satisfying EN 1504-2 class I requirements for breathable coatings. End-use configurations include bonding primers under epoxy flooring, acrylic paint tie-coats, and cementitious waterproofing slurries, where failure to consolidate the dust-laden surface would otherwise cause delamination under service loads exceeding 0.5 MPa tensile stress.

When DA-161 replaces acrylics in medical nonwoven lamination, sterilisation resistance becomes a design parameter

Sterilisable medical composite webs manufactured with DA-161 typically undergo ethylene oxide (EtO) processing, where residual emulsion components must not form ethylene glycol derivatives above 50 ppm per ISO 10993-7. The emulsion is formulated into a spray-bond adhesive by further blending with 0.8–1.2 wt% of a non-ionic acetylene diol wetting agent to reduce dynamic surface tension below 32 mN/m, enabling uniform deposition on 15–25 gsm spunbond polypropylene or wet-laid cellulose nonwovens at add-on levels of 6–10 g/m² dry. Application is accomplished via air-assisted hydraulic nozzles operating at 40–60 bar with a 0.3 mm orifice diameter, followed by through-air drum drying at 130°C for 6–8 seconds. The low glass transition temperature of DA-161 (-2 to +2°C as measured by DSC at 10 K/min) imparts a drape value below 50 mm in a cantilever stiffness test per ISO 9073-7, eliminating the need for external plasticisers that would otherwise leach out during ageing. Terminal articles include surgical drapes and fenestrated sheets, isolation gowns, and sterile barrier wraps, all required to meet EN 13795 liquid barrier performance after EtO treatment at 55°C for 3 hours and subsequent aeration. A critical quality checkpoint exists at the curing oven exit: surface tack measured by a Polyken probe at 23°C must fall below 10 g force within 30 seconds of cooling; elevated tack above 25 g causes web blocking on the wind-up roll at linear tensions above 50 N/m, leading to fibre pull-out and compromised sterile seal integrity. The absence of alkylphenol ethoxylates (APEOs) in DA-161 facilitates compliance with OEKO-TEX Standard 100 class I for infant articles and ZDHC MRSL conformance in the textile supply chain.

Headliner fabrication: peel resistance mapped against acoustic porosity in compression-moulded laminates

In headliner compression moulding, the backing adhesive layer applied via engraved roller coating to a fibreglass-reinforced polyurethane or PET felt core must maintain elongation above 300% after heat ageing at 90°C for 500 hours, as measured by DIN EN ISO 527-3 type 5 specimens. DA-161 is compounded in this process with 15–20 phr of a rosin ester dispersion to increase autogenous tack and with 2.0 phr of a hindered phenolic antioxidant (AO-2246 type) stabilised with a phosphite co-stabiliser at 0.5 phr to suppress oxidative degradation during the moulding cycle. The adhesive compound is applied at 35–50 g/m² dry weight to the reverse side of a polyester or trilobal nylon decorative cover fabric, then partially dried to 12% residual moisture before being positioned in a heated multi-cavity tool at 130–150°C with a dwell time of 40–55 seconds. Lamination pressure of 0.3–0.5 MPa is applied until the adhesive achieves gelation and begins foaming to fill the interstices of the felt substrate without fully penetrating, as penetration beyond 30% of felt thickness degrades acoustic absorption coefficient α below 0.65 in the 500–2000 Hz octave bands per ISO 10534-2 impedance tube measurements. The finished headliner, formed into a three-dimensional contoured part, is then subject to fogging tests per DIN 75201 with a condensate value below 0.5 mg and odour rating not exceeding grade 3 per VDA 270. Long-term delamination resistance under the thermal gradient of a vehicle roof (cyclic exposure from -30°C to 110°C) depends on the adhesion promoter level; the addition of 0.3 phr of an epoxy-functional silane to the DA-161 formulation raises peel strength after 10 thermal shock cycles from 2.8 N/25mm to 5.1 N/25mm when tested per SAE J1553 at 90° peel angle. A processing window violation occurs when the green strength build-up in the transfer time before press closure exceeds 40 seconds, because partial skin-over prevents the adhesive from wetting the felt fibres and results in a characteristic “orange peel” surface with reduced peel force below 2.0 N/25mm.

Dairen DA-161 is a vinyl acetate-ethylene (VAE) copolymer emulsion engineered with an elevated ethylene content, typically in the range of 22–26 wt%, to shift the glass transition temperature (T_g) below −20 °C as determined by differential scanning calorimetry per ISO 11357-2. The polymer is stabilised with a poly(vinyl alcohol) protective colloid system, yielding a medium-viscosity, pseudoplastic dispersion with a solids fraction of 55.0–57.0 % (ISO 3251, 105 °C/3 h). Within the Dairen portfolio, this grade occupies the high-ethylene end of the VAE spectrum, distinguished from DA-101 (ethylene ~14–16 %, T_g ~0 °C) and DA-102 (ethylene ~18–20 %) by a combination of permanent tack, cold-flexibility, and peel adhesion to low-surface-energy substrates without primer. Film formation occurs readily at temperatures below 0 °C; the minimum film-forming temperature (MFFT) measured by ISO 2115 is <1 °C, making the product operational in unheated application environments where PVAc homopolymers or low-ethylene VAEs would produce discontinuous, cracked films.

Typical Physicochemical Parameters and Colloidal Fingerprint

Lot-to-lot release data and indicative colloidal properties of DA-161
Property	Value	Method
Solids content	55.0–57.0 %	ISO 3251
Brookfield viscosity (RVT, #3/20 rpm, 25 °C)	500–2000 mPa·s	ISO 2555
pH	4.0–5.5	ISO 976
Average particle diameter	0.4–0.8 µm	Laser diffraction (Malvern Mastersizer)
T_g (midpoint, DSC)	−22 ± 3 °C	ISO 11357-2
MFFT	<1 °C	ISO 2115
Protective colloid	PVOH (partially hydrolysed, medium viscosity grade)	—

Variations in pH and viscosity between production batches are managed within a narrow processing window. Viscosity build observed upon addition of plasticisers such as dibutyl phthalate or benzoate esters follows a shear-thinning profile; in-line viscometry on production-scale mixing equipment (double-planetary mixer, vessel diameter 800 mm, tip speed 1.5 m·s⁻¹) indicates a plateau region where plasticiser uptake reaches 12–15 phr before phase inversion risk increases. Pre-drying of the compounded adhesive is unnecessary at relative humidity below 60 %, but storage of the raw emulsion must avoid repeated freeze-thaw cycling: after 3 cycles between −10 °C and 25 °C, grit content measured by 325-mesh sieve retention can exceed 450 ppm, a threshold above which nozzle clogging is observed on bead-coating lines.

When plasticised PVC film is laminated to MDF board using DA-161 applied via engraved roller (coat weight 25–35 g/m² wet), the immediate green tack supports transport over roller conveyors without film slippage. The bonding mechanism exploits the high ethylene segment mobility in the copolymer backbone, reducing the need for tackifier resin addition. Peel strength measured per ISO 11339 at 180° and 300 mm/min crosshead speed reaches 2.1–2.8 N/mm after 24 h ambient conditioning, with substrate failure occurring within the foam board rather than at the adhesive interface. In comparison, a standard 18% ethylene VAE yields 1.2–1.6 N/mm under identical conditions and typically requires an aromatic hydrocarbon tackifier at 8–10 wt% on solids to approach comparable values, at the cost of increased VOC emissions.

If LDPE to Paper Bonding Must Survive −30 °C Cold Chain Transport

Converters producing quick-freeze packaging for frozen seafood or ice cream often encounter adhesive embrittlement with conventional hot-melt or acrylic pressure-sensitive systems. DA-161, formulated with 2.5 phr acetyl tributyl citrate and applied at 18–22 g/m² dry on bleached kraft, retains lap shear strength above 1.0 MPa at −30 °C, measured in accordance with ASTM D1002 on 50 mm × 100 mm bonded area with an LDPE film gauge of 38 μm. The key difference from lower-ethylene VAE grades is the absence of a secondary β-relaxation peak above −30 °C in dynamic mechanical analysis (DMA), as the ethylene-rich chain segments suppress the β-transition associated with local-mode motions of the acetate side groups. This translates to flexible rather than glassy failure mode under sub-zero peel forces, a field-validated observation on a vertical form-fill-seal line running at 60 packs/min with 0.8 s dwell time.

Incompatibility with certain amine-based anti-foaming agents must be highlighted. Addition of 0.1 wt% of a fatty amine defoamer triggered a rapid viscosity hike exceeding 12 000 mPa·s within 90 s on a production trial with an in-line static mixer (Kenics type, 10 elements). The rise is attributed to disruption of the PVOH stabilisation layer through acid-base interaction with residual acetate groups; mineral oil-based defoamers at equivalent dosage maintain stable rheology over a 4 h pot life. Cleaning protocols for mixing vessels switching from acrylic- or PUR-based adhesives to DA-161 must eliminate residual isocyanate or amine residues, as even 50 ppm crosslinker carryover generates grits exceeding 250 μm in a hot-box stability test at 50 °C for 7 days.

Carpet pre-coat and secondary backing: tuft lock without crosslinker

In tufted carpet pre-coat lines using blade-over-roll application, compound formulations containing 400 phr calcium carbonate (mean particle size 15 μm) and 100 phr DA-161 emulsion exhibit mechanical stability measured by Fisher-Sanderson probe, with no detectable coagulum after 6 h recirculation at 40 °C. Tuft lock values per ASTM D1335 exceed 5.5 kgf on a loop-pile PP face fiber when latex loading is adjusted to 18 % dry add-on by fabric weight. The high ethylene content provides wet-end compatibility with the calcium stearate secondary backing compound without the need for additional polyacrylate thickeners; the system rheology remains shear-thinning with a power-law exponent n = 0.42 across the shear rate range 10–1000 s⁻¹, ensuring stable coating weight control on lines with 3.5 m working width and belt speeds up to 25 m/min.

Comparative oven profiling on a three-zone gas-fired tenter (zone 1: 120 °C, zone 2: 140 °C, zone 3: 130 °C) shows that DA-161 films achieve full moisture loss at 8 % shorter dwell than a standard SBR latex pre-coat, attributable to lower capillary retention in the ethylene-rich polymer network. Dimensional stability of the finished carpet, assessed by ISO 2551 submersion test (2 h water soak, 60 °C), gave area change <0.4 %, within the EN 1307 class for contract use, a performance edge attributed to reduced water uptake of the VAE film compared with styrene-butadiene counterparts.

Textile laminators utilising DA-161 for interlining fusible coatings incorporate a blocked isocyanate crosslinker at 2.0–2.5 % active on emulsion solids to elevate the softening point above 160 °C. After activation at 140 °C for 30 s, the crosslinked film withstands dry-cleaning solvents (perchloroethylene, 3 cycles) without delamination, meeting ISO 3175-2 requirements. Without crosslinker, the film softens at 80–90 °C and peels at 0.6 N/mm after solvent exposure; with crosslinker, peel strength sustains above 2.0 N/mm. This trade-off is unavailable with acrylic emulsions, which require higher cure temperatures or catalyst packages that can yellow the fabric.

What shifts adhesive performance when the substrate changes from polar wood to hydrophobic OPP?

On wood-to-wood assemblies (beech, 12 % moisture content), DA-161 delivers compression shear strength per EN 205 of 10–12 MPa at 150 g/m² coat weight, bonding without hardener. When the same formulation is applied to oriented polypropylene film (corona-treated to 42 dyn/cm, measured per ISO 8296), peel force on T-peel geometry (ASTM D1876) degrades to 0.8 N/mm unless the formulation is modified with 5 wt% of an aliphatic hydrocarbon resin having a softening point of 95 °C. The resin raises peel to 2.3 N/mm while maintaining optical clarity in the adhesive line. This sensitivity stems from the PVOH colloid, which imparts excellent cellulose affinity but limits specific adhesion to polyolefins unless the interfacial energy mismatch is compensated by tackifier segments. In contrast, a pure acrylic pressure-sensitive adhesive might not require a tackifier but would fail the FDA 21 CFR 175.105 indirect food contact requirement that DA-161 meets, making it viable for dry food packaging laminations.

How DA-161 departs from standard VAE and PVAc dispersions

Differentiation matrix for Dairen VAE emulsions and a representative PVAc homopolymer
Parameter	DA-161	DA-102	DA-101	PVAc (DA-901)
Ethylene content, %	22–26	18–20	14–16	0
T_g, °C	−22	−10	0	+30
MFFT, °C	<1	3–5	8–12	17–20
Peel on BOPET, N/mm (ASTM D3330)	1.8 (tackified)	1.2	0.7	<0.3 (no tack)
Water whitening ( 24 h soak)	Slight haze, reversible	Moderate haze	Opaque	Heavy whitening
FDA 21 CFR 175.105	Compliant	Compliant	Compliant	Compliant
EN 71-3 migration of elements	Pass	Pass	Pass	Pass

The permanent tack characteristic of DA-161 arises from its ethylene segment dynamics, not from post-added plasticiser. This yields a resistance to tack degradation upon aging at 70 °C for 14 days: loop tack per FTM-9 measure drops less than 15 % from initial, whereas a plasticised PVAc loses over 50 % due to plasticiser migration into the substrate. Such behaviour is critical in automotive interior lamination where fogging limits are governed by DIN 75201-B; formulations based on DA-161 yield condensate values <1 mg in fogging tests, well under the 2 mg typical upper limit for interior components.

Production staff working with DA-161 note that clean-up is slightly more demanding than with low-ethylene VAEs after machine stoppages exceeding 30 minutes. The dried film exhibits greater extensibility (800–1000 % elongation at break per ISO 527-3) and resists fracture under mechanical wiping; a 5 % aqueous ammonia solution at 40 °C applied through a CIP (clean-in-place) spray ball for 15 min effectively re-solubilises the film when downtime is unavoidable. Storage stability in sealed totes at 5–35 °C extends to 12 months (manufacturer specification), but partial settlement may be observed after 6 months; gentle drum rotation for 5 min at 10 rpm restores homogeneity without generating foam.

In high-frequency wood assembly operations where a PVAc homopolymer would require radio-frequency curing due to its high T_g, DA-161 replaces the need for such capital equipment by providing adequate cohesive strength from ambient drying alone. Testing on a carcase clamp rack with 80 N/cm² clamping pressure gave handling strength within 20 min at 22 °C and 55 % RH, a cycle-time reduction of approximately 40 % compared with a grade like DA-901. The economic offset arises from lower energy consumption per assembled unit, though high-humidity conditions (>75 % RH) extend open time beyond 8 min and may require forced air circulation of 1.5 m/s across the bond line to maintain takt time.

HS Code	876824
Product Name	Dairen DA-161 VAE Emulsion
Chemical Family	Vinyl Acetate-Ethylene Copolymer
Appearance	Milky white liquid
Solid Content	55 ± 1%
Viscosity	8000 - 15000 mPa·s (Brookfield, 25°C)
Ph	5.0 ± 1.0
Glass Transition Temperature	0°C
Minimum Film Forming Temperature	0°C
Particle Size	0.1 - 0.3 μm
Specific Gravity	1.05 - 1.10
Surface Tension	40 ± 5 mN/m
Water Resistance	Good

Packing	Dairen DA-161 VAE Emulsion is supplied in 200 kg net polyethylene-lined drums, sealed to prevent evaporation and contamination.
Container Loading (20′ FCL)	20′ FCL: Dairen DA-161 VAE Emulsion loaded in palletized drums/IBCs, secured with dunnage, standard dry container, no hazmat restrictions.
Shipping	Dairen DA-161 VAE Emulsion ships as a non-hazardous aqueous polymer dispersion in drums or IBC totes. Protect from freezing and excessive heat; ideal storage above 5°C. No dangerous goods classification applies under normal conditions, but provide MSDS, batch documentation, and ensure containers are sealed, labeled, and ventilated during transport.
Storage	Store Dairen DA-161 VAE Emulsion in original, tightly sealed containers in a cool, dry, well-ventilated area. Keep temperature between 5°C and 40°C; do not allow freezing. Protect from direct sunlight, heat sources, and moisture. Avoid prolonged exposure to air to prevent skinning. Keep away from incompatible materials, sparks, and open flames. Use within shelf life with regular agitation before use.
Shelf Life	Store in sealed containers at 5–35°C, away from frost. Shelf life: 12 months from manufacture date.

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