Reclosable fasteners, packages having reclosable fasteners, and methods for creating reclosable fasteners
A UV-curable pressure sensitive adhesive, a package having an adhesive-based reclosable fastener including the pressure sensitive adhesive, and a method of forming the package is described herein. The package includes a cavity and opposing panels configured to cover an opening to the cavity. The reclosable fastener is a UV-cured pressure sensitive adhesive comprised of one or more UV-curable acrylic oligomers, one or more tack control components, and, optionally, an elastomeric material. An adhesive component ratio defines an effective ratio made up of the weight percent of the UV-curable acrylic oligomer relative to the sum of the weight percents of the tack control component and elastomeric component, where the ratio provides a fastener with a first peel adhesion and subsequent peel adhesions effective to form the adhesive-based fastener into a reclosable fastener.
1. A package having an adhesive-based reclosable fastener, the package comprising:
walls forming a cavity for receiving one or more products;
opposing panels of the walls;
a reclosable UV-cured adhesive-based fastener supplied from opposing adhesive portions of a UV-cured pressure sensitive adhesive with one of the opposing adhesive portions disposed on each of the opposing panels, the UV-cured pressure sensitive adhesive including at least one UV-curable acrylic oligomer, at least one tack control component, and optionally at least one elastomeric material;
an adhesive component ratio (ACR) of the UV-cured pressure sensitive adhesive defined by formula (A) where the weight percent of the UV-curable acrylic oligomer relative to the sum of the weight percents of the tack control component and the optional at least one elastomeric material is about 0.5 to about 1.5
(
wt
%
UV
-
curable
acrylic
oligomer
)
(
wt
%
tack
control
component
+
wt
%
elastomeric
material
)
;
(
A
)
the ACR effective so that the reclosable UV-cured adhesive-based fastener has a first peel adhesion between the opposing adhesive portions of about 200 grams per linear inch (gpli) to about 900 gpli and up to five subsequent peel adhesions between the opposing adhesive portions each about 30 percent to about 200 percent of the first peel adhesion;
wherein the ACR and the package walls are effective to form a bond strength of the UV-cured pressure sensitive adhesive to the opposing panels greater than the first peel adhesion and the subsequent peel adhesions between the opposing adhesive layers so that the opposing panels can be repeatedly peeled open without delaminating the opposing adhesive layers from the opposing panels, and wherein the UV-cured pressure sensitive adhesive has a stronger cohesive bond to itself than a bond to non-adhesive or non-cohesive materials without the UV-cured adhesive delaminating from the opposing walls.
2. The package of claim 1 , wherein a mixture of the UV-curable acrylic oligomer, the tack control component, and the optional at least one elastomeric material prior to being applied to the packaging substrate are compatible so that an uncured pressure sensitive adhesive remains a stable liquid that is homogeneous without phase separation for at least about 3 days at about 21° C. to about 24° C. and has a viscosity of about 2,000 cPs or below at about 70° C. to about 75° C.
3. The package of claim 1 , wherein the UV-cured pressure sensitive adhesive exhibits a first subsequent peel adhesion after contamination with debris of at least about 50 percent of the first peel adhesion.
4. The package of claim 1 , wherein the UV-cured pressure sensitive adhesive includes about 1 percent to about 90 percent of the UV-curable acrylic oligomer, about 1 percent to about 65 percent of the tack control component, and about 5 percent to about 20 percent of the at least one elastomeric material; and wherein the UV-cured pressure sensitive adhesive forms the reclosable fastener exhibiting a rolling ball tack up to about 14 inches.
5. The package of claim 4 , wherein the UV-curable acrylic oligomer is an acrylic acid ester.
6. The package of claim 1 , wherein the at least one elastomeric material includes one of curable elastomeric acrylate esters or methacrylate esters selected from the group consisting of acrylated polybutadiene, saturated polybutadiene, and polyurethane.
7. The package of claim 1 , wherein the tack control component is an aliphatic urethane acrylate oligomer.
8. The package of claim 1 , wherein the bond strength of the UV-cured pressure sensitive adhesive to the package walls is greater than about 600 gpli and withstands at least 100 double rubs of methyl ethyl ketone.
9. The package of claim 1 , wherein the package walls include at least a sealant layer on the opposing panels including adhesion promoting filler particles and to which each of the opposing adhesive layers is applied.
10. The package of claim 9 , wherein the sealant layer includes a blend of ethylene vinyl acetate (EVA), polyethylene, and a filler composition including the adhesion promoting filler particles and a polymeric carrier resin.
11. The package of claim 10 , wherein the polymeric carrier resin includes a maleic anhydride grafted polyethylene, polyethylene, and blends thereof; and wherein the EVA forms a continuous phase with the polyethylene, the adhesion promoting filler particles, and the maleic anhydride grafted polyethylene dispersed therein.
12. The package of claim 10 , wherein the sealant layer includes about 60 percent to about 80 percent EVA, about 5 percent to about percent 20 percent polyethylene, and about 3 percent to about 20 percent filler composition.
13. The package of claim 12 , wherein the sealant layer has been corona treated.
14. The package of claim 1 , wherein the package walls include adhesion promoting filler particles.
15. The package of claim 14 , wherein the adhesion promoting filler particles are montmorillonite modified with ammonium salt surfactants.
16. The package of claim 15 , wherein the modified montmorillonite is supplied with a carrier including maleic anhydride grafted polyethylene, polyethylene, and blends thereof.
17. The package of claim 1 , wherein the subsequent peel adhesions are each at least about 200 gpli.