Waterborne adhesives for reduced basis weight multilayer substrates and use thereof
The adhesive composition comprising emulsion polymers and microspheres and articles made therefrom are provided. The adhesive is particularly suitable for packages for consumer products that provide sufficient strength and thermal insulation while reducing the overall basis weight of the substrates.
1. A method of making an article with improved structural integrity, comprising the steps of:
(a) providing a first substrate having a first and a second side;
(b) preparing an adhesive composition by combining (i) an emulsion-based polymer selected from the group consisting of vinyl acetate ethylene dispersion, polyvinyl acetate, polyvinyl acetate polyvinyl alcohol, dextrin stabilized polyvinyl acetate, polyvinyl acetate copolymers, vinyl acetate ethylene copolymers, vinylacrylic, styrene acrylic, acrylic, styrene butyl rubber, polyurethane and mixtures thereof; (ii) about 0.5% to about 5%, based on the total weight of the adhesive, of a plurality of expandable microspheres having an expansion temperature (T exp ) and a maximum expansion temperature (T max );
(c) applying the adhesive onto the first side of the first substrate;
(d) providing a second substrate having a first and a second side;
(e) contacting the first side of the second substrate directly on the adhesive to form the article;
(f) applying heat at a temperature range between the T exp and T max to expand the plurality of expandable microspheres; and
(g) drying the adhesive to form a bond adhering the first and the second substrates;
wherein the article has substantially similar thermal insulation loss with up to about 26% decrease in substrate basis weight than an article without the microspheres.
2. The method of claim 1 wherein the first substrate and the second substrate, independently, is a fiberboard, corrugated board, SBS, kraft paper, coated paper or oriented polypropylene film.
3. The method of claim 1 wherein the basis weight of the first substrate and the second substrate ranges from 2 to 35 pounds per 1000 ft 2 .
4. The method of claim 1 , wherein the first substrate and the second substrate comprise a portion of recycled fiber.