VAE Emulsion CW 40‑905 is a high‑solids aqueous dispersion of a vinyl acetate‑ethylene (VAE) copolymer. The product is supplied at a nominal solids content of
54.5 ± 1.0 % by weight (per
ASTM D2369‑07), with a Brookfield RVT viscosity at
20 °C and
20 rpm typically falling in the range
2 200 – 3 800 mPa·s (spindle
#4,
ISO 2555:2018). The pH, as measured on a calibrated electrode without dilution, lies between
4.2 and
5.0. The colloidal stabilisation system is based on a combination of poly(vinyl alcohol) (PVOH) of intermediate hydrolysis degree and a small quantity of anionic surfactant; this yields a mean particle size between
0.8 µm and
1.4 µm, determined by laser diffraction on a Malvern Mastersizer 3000. Because the ethylene content of the backbone is relatively high — in the region of
15 – 18 % by weight of total polymer — the glass‑transition temperature (Tg) of the dried film, measured by differential scanning calorimetry according to
ISO 11357‑2:2020, is approximately
−14 °C, and the minimum film‑forming temperature (MFFT) on a bar coater (
ISO 2115:1996) is consistently
<0 °C. These thermal properties differentiate CW 40‑905 sharply from conventional PVAc homopolymer emulsions with Tg values above
30 °C and from lower‑ethylene VAE grades (Tg near
0 – 5 °C) that require external plasticisers or high‑boiling coalescents to achieve adequate film integrity at ambient temperature.
Key Product Specifications and Physical Constants
The following table compiles the principal physico‑chemical benchmarks for CW 40‑905 against a lower‑ethylene VAE grade and a traditional plasticised PVAc homopolymer. All data refer to freshly produced lots conditioned at
23 ± 2 °C and
50 ± 5 % relative humidity.
| Property |
CW 40‑905 |
VAE (low ethylene) |
PVAc homopolymer (plasticised) |
| Solids content [%] |
54.5 ± 1.0 |
52.0 ± 1.0 |
50.0 ± 1.0 |
| Brookfield viscosity [mPa·s] |
2 200 – 3 800 |
1 800 – 2 800 |
8 000 – 14 000 |
| pH |
4.2 – 5.0 |
4.0 – 5.0 |
4.5 – 5.5 |
| Tg (DSC midpoint) [°C] |
≈ −14 |
≈ +3 |
≈ +33 |
| MFFT [°C] |
<0 |
≈ +6 |
≈ +15 (unplasticised) |
| Surface energy of dried film [mN/m] |
38 – 42 |
40 – 44 |
36 – 40 |
The above data illustrate why CW 40‑905 acts as an internal‑plasticised binder. Its sub‑zero MFFT eliminates the need for coalescing solvents in many waterborne adhesive and coating formulations, directly supporting low‑VOC (<1 g/L per EPA Method 24) product labelling. The relatively low dried‑film surface energy widens the adhesion window to substrates with weak boundary layers, such as corona‑treated polypropylene or lightly sanded rigid PVC.
How Does the Ethylene Content Impact Minimum Film‑Forming Temperature and Coalescent Demand?
The higher ethylene fraction in CW 40‑905, relative to standard VAE emulsions with
8 – 12 % ethylene, reduces the cooperative segmental mobility required for particle coalescence. The copolymer backbone contains short polyethylene sequences that act as internal “spacers,” depressing the effective Tg by roughly
2 °C per weight‑percent ethylene. Consequently, a film deposited from CW 40‑905 at
10 °C and
70 % RH develops full coalescence and
≥ 95 % of ultimate tensile strength within
48 h without any added Texanol or butyl glycol ether. Comparative open‑time measurements on a BYK stainless‑steel bar coater (wet film thickness
200 µm) show that the high‑ethylene grade remains tacky and workable for
6 – 8 min, whereas a low‑ethylene VAE skin‑over in less than
3 min under identical conditions. This extended open time is exploited in high‑speed wood‑lamination and foil‑to‑paper converting where machine‑direction splicing must occur without flash‑drying of the adhesive.
The absence of external plasticisers carries a penalty: the shear‑modulus of the fully coalesced film at
23 °C is only
0.3 – 0.7 MPa (dynamic mechanical analysis,
1 Hz), which renders the neat polymer too compliant for structural‑bonding applications. Formulators compensate by blending with high‑Tg dispersions, reactive crosslinkers, or by leveraging the VAE as a flexible primer layer beneath a rigid top‑coat. The compounding latitude is broad because CW 40‑905 accepts fillers up to
30 % calcium carbonate loading before film continuity is compromised.
What Limits Liquid Hourly Space Velocity in TCE Production?
When CW 40‑905 is deployed as a fibre‑bonding binder in non‑woven production, the drying‑limited line speed often exceeds
180 m/min on single‑pass through‑air ovens set at
135 °C. However, production experience on a Fleissner drum dryer indicates that exceeding
200 m/min induces surface skinning and internal steam‑blistering that reduces cross‑directional tensile strength by up to
15 %. Plant trials documented that lowering the web basis weight by
2 gsm while raising oven temperature to
140 °C restored uniform curing, demonstrating that the critical parameter is the product of residence time and wet‑film thickness, not merely line velocity.
When Bonding Plasticized PVC to Wood Substrates
In furniture‑edge‑banding lines using a hot‑melt‑onto‑VAE primer architecture, CW 40‑905 functions as the solvent‑free adhesion promoter applied by curtain coater at a dry coating weight of
4 – 6 g/m². The primer layer must plasticise the PVC edge band without itself migrating into the hot‑melt adhesive interlayer. Accelerated ageing at
60 °C and
90 % RH for
14 days, followed by
180° peel testing per
ASTM D903‑98, reveals that CW 40‑905 maintains an average peel strength of
4.8 N/mm on Di‑iso‑octyl phthalate‑plasticised PVC, compared with
2.9 N/mm for a conventional EVA‑dispersion primer of equivalent solids. This difference is attributed to the low‑Tg ethylene domains that absorb plasticiser from the PVC without becoming tacky and cohesive‑failure‑prone. Published data for this specific configuration is limited to internal manufacturer evaluations; no peer‑reviewed interlaboratory study is available.
Because the primer must wet the wood surface and penetrate the vessel lumens, the emulsion is commonly diluted to
25 – 30 % solids. Dynamic wetting measurements on pine sapwood using a Krüss K100 tensiometer show a contact‑angle equilibrium of
42 ± 3° within
0.8 s, significantly faster than surfactant‑stabilised acrylics that require
2.5 s to reach an equivalent state. In‑plant experience confirms that the rapid wetting translates to a
20 % reduction in primer consumption when switching from an acrylic‑styrene latex, as overspray and puddling are minimised.
Polymer Backbone Architecture and Its Influence on Wet Adhesion Durability
Wet adhesion performance in high‑humidity environments is governed by the hydrolytic stability of the vinyl acetate‑ethylene copolymer. Unlike pure PVAc, which hydrolyses readily at alkaline pH above
8, the ethylene sequences in CW 40‑905 interrupt the acetate backbone, slowing the rate of cleavage. Submersion tests (deionised water,
23 °C,
7 days) on films cast over aluminum Q‑panels and tested in cross‑hatch per
ISO 2409:2020 showed
98 % retention of coating, whereas a PVAc homopolymer control delaminated to
35 % retention. When the composite adhesive formulation is buffered with
0.2 % sodium bicarbonate to a pH of
7.2, the wet‑adhesion lifetime under
40 °C water immersion extends beyond
1 000 h before blistering appears. Formulators should avoid combination with amino‑functional silanes such as N‑(2‑aminoethyl)‑3‑aminopropyltrimethoxysilane when curing at temperatures above
60 °C, as the alkaline hydrolysis of the amine accelerates acetate group removal and reduces film integrity markedly.
Thermal Aging Behavior under Isothermal Loading
Neat films of CW 40‑905, when heat‑aged at
120 °C in a forced‑air oven, develop colour from water‑white to a Gardner index of
2 within
48 h, then remain stable for an additional
96 h. The elongation at break, measured on universal testing machine per
ISO 37:2017 type‑2 dumbbells, declines from an initial
800 % to
620 % after
144 h, while tensile strength increases from
4.2 MPa to
5.8 MPa, a signature of post‑curing but not embrittlement. This behaviour is exploited in lamination of PVC‑mesh for outdoor advertising, where the emulsion is thermoplastically reactivated during hot‑nip calendering at
140 °C. Production‑scale observations on a KKA hot‑nip calender (roll diameter
600 mm, line speed
12 m/min) indicate that pre‑drying the emulsion‑coated fabric to a moisture content below
0.3 % is essential: residual water at
0.5 % causes blistering in the nip, lowering peel strength by
30 %.
Rheology Control and Machine‑Application Constraints
For roller‑coating operations, the Newtonian‑like flow of CW 40‑905 below a shear rate of
50 s⁻¹ necessitates the addition of a high‑shear associative thickener, typically a hydrophobically modified ethoxylated urethane (HEUR) at
0.05 – 0.15 % active on emulsion weight. Without thickener, curtain stability fails above
100 m/min. Thickener addition must be performed under slow agitation (
200 rpm with a paddle blade) to avoid foam entrapment; in‑line defoaming with
0.02 % of a silicone‑free, polyether‑based defoamer is recommended. Batch‑to‑batch viscosity drift in summer months — when ambient temperature in un‑air‑conditioned storage rises above
30 °C — has been traced to post‑polymerisation of residual vinyl acetate monomer (RVM), which in fresh lots is maintained below
500 ppm (
ASTM D4747‑02). To counteract the drift, pre‑blend checking of viscosity and adding
0.01 % of a tertiary butyl hydroperoxide scavenger is practiced in some large‑volume lamination plants.
Regulatory Conformance and Industrial Hygiene
The product contains no added alkylphenol ethoxylates, phthalates, or heavy‑metal catalysts, and satisfies the requirements of the European REACH Regulation (
EC No. 1907/2006) as a polymer of low concern. Formaldehyde content, measured by the acetylacetone method (
ISO 14184‑1:2011), is
<10 ppm, enabling compliance with the U.S. CARB Phase
2 emission limits for composite wood products. The following table summarises the relevant directives.
| Regulation /Standard |
Requirement |
Status for CW 40‑905 |
| EU REACH (annex XVII) |
Restrictions on phthalates, APEO |
None detected |
| RoHS 3 (EU 2015/863) |
Pb, Hg, Cd, Cr(VI), PBB, PBDE, DEHP, BBP, DBP, DIBP |
Below MCV thresholds |
| FDA 21 CFR 175.105 |
Adhesives for indirect food contact |
Compliant when formulated correctly |
| BfR Recommendation XIV |
Polymer dispersions for food contact coatings |
Positive listing of monomers |
| ASTM D6886‑18 |
Specification for determination of VOC in waterborne adhesives |
VOC <0.3 % by weight |
In concentrated form, the low pH may cause mild skin irritation; engineering controls such as open‑tank ventilation and nitrile glove use are standard in automated dosing stations. The product has a minimum storage stability of
6 months at
5 – 35 °C when kept in sealed HDPE totes. Freezing irreversibly destabilises the dispersion, leading to grit formation>
250 µm that cannot be re‑dispersed. Drum‑stock that has been partially emptied and left in a humid environment above
60 % RH may form a surface skin that, if reintroduced into the bulk, acts as a seed for further coagulation. Plant practice is to blanket the headspace with nitrogen or to transfer to a nitrogen‑padded day tank when ambient relative humidity exceeds
65 %.
Re‑dispersible Powder Analogue and Thermoplastic Film Conversion
Although CW 40‑905 is not supplied in spray‑dried powder form, its high‑ethylene composition suggests that a protective‑colloid‑stabilised version could yield a re‑dispersible polymer powder with a lower Tg limit near
−10 °C, suitable for cementitious tile adhesives requiring cold‑weather flexibility. Published data on the spray‑drying behaviour of this specific emulsion is limited, but trials with a Niro atomiser at inlet temperature
140 °C and outlet
65 °C have been conducted internally, showing
90 % retention of original MFFT when combined with
8 % PVOH as spray‑drying aid. The resultant powder, after reconstitution, still displays the same exceptionally low‑temperature coalescing ability. In thermoplastic film manufacturing, the emulsion can be cast onto a release liner and dried to produce a flexible, peelable, pre‑formed adhesive layer with a tack index (loop‑tack,
FINAT FTM 9) of
5.2 N/25 mm that remains stable over
6 months of ambient ageing, a performance metric that competes directly with solvent‑cast acrylic pressure‑sensitive adhesives minus the VOC penalty.
