Heat activated adhesives for bag closures
View Patent ↗A polymeric woven bag has a first panel and a second panel and an open end of the bag to be pinched closed. A first layer of heat activated adhesive material is on a portion of the bag to form an adhesive-to-adhesive seal by contact with a second layer of heat activated adhesive material on a portion of the bag, wherein a chemical family of the adhesive layers comprises polyolefin thermoplastic components, and wherein the first adhesive layer and the second adhesive layer have respective heat activation temperatures below the softening point temperature of the polymeric bag material.
1. A polymeric woven bag, comprising:
An outer layer of polymeric material;
a woven bag layer of polymeric material;
a first panel and a second panel and an open end of the bag to be pinched closed between the first panel and the second panel after filling the bag with contents;
a first portion of the bag having a heat activated first adhesive layer of a hot melt adhesive;
a second portion of the bag to be pinch closed with the first portion having a heat activated, second adhesive layer of a hot melt adhesive, wherein a chemical family of the adhesive layers comprises polyolefin thermoplastic components, the first adhesive layer and the second adhesive layer have respective heat activation temperatures below the softening point temperature of the polymeric material, and the first adhesive layer and the second adhesive layer are activatable to adhesive states to form an adhesive-to-adhesive seal to seal the open end of the bag by an application of heat at a temperature below the softening point temperature of the polymeric material, and without heating the first adhesive layer and the second adhesive layer to their melt flow state temperatures;
wherein the heat activated adhesive layers extend in an area across the bag and the layers have respective widths ranging from ½ inch to 6 inches.
2. The polymeric woven bag of claim 1 , wherein each of the first adhesive layer and the second adhesive layer comprises a solvent based adhesive.
3. The polymeric woven bag of claim 1 , wherein each of the first adhesive layer and the second adhesive layer comprises a liquid state, acrylated epoxy based adhesive soluble in an air dryable solvent.
4. The polymeric woven bag of claim 1 , wherein the first adhesive layer and the second adhesive layer comprise adhesive materials solidified after their application to the portion of the first panel and the portion of the second panel, respectively.
5. The polymeric woven bag of claim 1 , wherein the first adhesive layer and the second adhesive layer are the same material.
6. The polymeric woven bag of claim 1 , wherein the portion on the second panel comprises a sealing flap portion and the second adhesive layer is on the sealing flap portion.
7. The polymeric woven bag of claim 1 , wherein the bag is foldable to fold the portion of the first panel on itself, and wherein the sealing flap portion is foldable toward the first panel to hold the bag folded by contact between the first adhesive layer and the second adhesive layer.
8. The polymeric woven bag of claim 7 , wherein the first adhesive layer and the second adhesive layer are on opposite panels of the bag.
9. The polymeric woven bag of claim 7 , wherein each of first adhesive layer and the second adhesive layer comprises polymeric adhesive dispersed in water having a melt temperature below 300° F. and below the softening point temperature of the polymeric material of the bag.
10. The polymeric woven bag of claim 1 , wherein the softening point temperature of the hot melt adhesive is about 150° C.
11. The polymeric woven bag of claim 1 , wherein the viscosity of the hot melt adhesive is about 10,500 to 16,000 mPas/cPs.