Adhesive having structural integrity and insulative properties
An adhesive composition that provides improved structural integrity and insulative properties when applied to a substrate is provided. The adhesive composition includes an emulsion-based polymer, a plurality of microspheres; and optionally, water and plasticizer.
1. An adhesive composition to decrease the basis weight of a substrate comprising:
(a) about 50 to about 70 weight percent of an emulsion polymer selected from the group consisting of vinyl acetate-ethylene copolymer, polyvinyl acetate-polyvinyl alcohol copolymer, dextrin-stabilized polyvinyl acetate copolymer, polyvinyl acetate copolymers, and mixtures thereof;
(b) about 0.1 to about 10 weight percent of a plurality of expandable microspheres that are expandable in the presence of heat and/or radiation; and
(c) water; and
wherein the total adhesive composition weight percent is calculated without component (c) water;
wherein the emulsion polymer has a solids level of from about 40 weight percent to about 60 weight percent, based on the emulsion polymer;
wherein the adhesive composition is a water-based resin emulsion.
2. The adhesive composition of claim 1 , wherein said expandable microspheres comprise polymeric microspheres have an initial expansion temperature (Texp) and a maximum expansion temperature (Tmax).
3. The adhesive composition of claim 1 , wherein said plurality of expandable microspheres are present in an amount of from about 0.5 weight percent to about 5 weight percent.
4. The adhesive composition of claim 1 , further comprising a plasticizer and/or a preservative.
5. The adhesive composition of claim 2 , wherein said expandable microspheres has a Texp of about 80° C. to about 90° C. and a (Tmax) about 120° C. to about 140° C.
6. The adhesive composition of claim 1 , wherein the adhesive further comprises a crosslinker, filler, pigment, dye, stabilizer, rheology modifier, polyvinyl alcohol, humectant and mixtures thereof.
7. The adhesive composition of claim 1 , wherein the adhesive further comprises an accelerator that is a multivalent water-soluble salt.
8. An expanded adhesive composition prepared by
(1) forming an unexpanded adhesive, which is a water-based resin emulsion comprising:
(a) about 50 to about 70 weight percent of an emulsion polymer, having a solids level of from about 40 to about 60 weight percent based on the emulsion polymer, selected from the group consisting of vinyl acetate-ethylene copolymer, polyvinyl acetate-polyvinyl alcohol copolymer, dextrin-stabilized polyvinyl acetate copolymer, polyvinyl acetate copolymers, and mixtures thereof
(b) about 0.1 to about 10 weight percent of a plurality of expandable microspheres; and
(c) water; and
wherein the total adhesive weight percent is calculated without component (c) water;
(2) expanding the expandable microspheres with heat and/or radiation; and
(3) drying the water from the water-based resin emulsion;
wherein the dry volume of the expanded adhesive composition is at least 400% greater than the dry volume of the unexpanded adhesive.