Fields of application

ACRONAL DS 2159 may be used as a binder for filled construction adhesives, such as AFG-01 plywood-lumber subfloor formulations where superior moisture resistance is required.

Processing

Subfloor adhesives are produced from ACRONAL DS 2159 by conventional formulating techniques. In order to ensure that the viscosity of the made-up adhesive does not undergo any change during long storage periods, the pigments and extenders must be dispersed with adequate amounts of wetting and dispersing agents; e.g., Pigment Disperser A, together with polyphosphates.

Various thickeners may be added to regulate the viscosity and flow, as well as to improve gunnability. Polyacrylates, cellulose ethers, Collacral VL or polyurethane thickeners, either by themselves or in combination, may be used for this purpose. Inorganic thickeners, e.g., montmorillonites and finely divided silica, are also suitable. Laboratory testing for compatibility of ingredients and long-term storage/viscosity stability should be carried out.

In common with all other fine particle size dispersions, ACRONAL DS 2159 may foam when agitated. Defoamers in proportions recommended by the manufacturer (usually of the order of 0.05 – 0.5%) may be added. Its efficiency should be checked by prior experiment.

Small amounts of coalescents may be included in formulations in order to ensure film formation at temperatures below 57 °F. Suitable solvents for this purpose are glycol ethers and their acetates, mineral spirit containing aromatics, and Texanol, either individually or mixed together. In general, the maximum proportion that would suffice for coalescents is 3%, expressed in terms of the total made-up adhesive. Solvents that are freely miscible with water, e.g., lower alcohols or glycols, are unsuitable coalescents, but improve the frost stability of the formulation and promote adhesion to frozen lumber substrates. Water-miscible highboilers, e.g., propylene glycol and diethylene glycol monobutyl ether, also lengthen the wet edge time and increase sensitivity to water.

Solvents and thickeners in the concentrated form should not be added directly to the dispersion because of the risk of local coagualtion. It is preferable to mix them with the pigment paste or dilute them with water before they are incorporated in the adhesive.

Preservatives must be added as a safeguard against microorganisms if the formulated adhesives are to be stored for long periods. Their compatibility and efficiency should be checked by prior experimentation. The proportions to be added depend on the manufacturer’s instructions and the ambient storage conditions.

Manufacturers must perform their own trials in developing water-based adhesives from ACRONAL DS 2159 because experiments on our part cannot embrace the great variety of factors that may exert an influence on production and application; e.g., the mutual compatibility of the constituents, the mechanisms that occur during mixing and the adhesion to various substrates.