Strong and stretchable seam tape
The present invention relates to a seam tape comprising at least one layer of unidirectionally aligned fibers whereby the fibers are oriented substantially perpendicular to the length of the tape and the strength of the tape in the perpendicular direction is at least 200 N/2.54 cm [inch]. The fibers are selected from the group of UHMWPE, polyamide, polyester, glass or carbon fibers. Preferably the fibers are UHMWPE fibers. The seam tape may further comprise a hot melt adhesive. The hot melt adhesive preferably has a melting point which is at least 25° C. to 70° C. lower than the melting point of the fibers. The hot melt adhesive is chosen from the group consisting of thermoplastic polymers such as polyamides, co-polyamides, polyamino-amides, polyesters, polyacrylates, polymethacrylates, polyolefins, ethylene/vinyl acetate copolymers or mixtures thereof. The present invention further relates to the use of the seam tape in backpacks, packs, bags, medical gear, outdoor products, sail cloths, tents, tarps, shelters, clothing, ponchos, foul weather gear, mats, outerwear, jackets, sleeping bags, lift bags, parachutes, large kites, inflatable structures, beams, balloons, packraft, inflatable gear, liferaft, inflatable sculptures, airship (HAA: High Altitude Airships), space applications, flexible circuits and footwear, inflatables, radomes, tensioned structures, or umbrellas.
1 . A seam tape having length and width dimensions, the seam tape comprising:
at least one fiber layer, and
a hot melt adhesive film layer, wherein
the at least one fiber layer comprises:
(i) a flexible polymeric matrix material, and
(ii) ultrahigh molecular weight polyethylene (UHMWPE) fibers which are unidirectionally aligned and oriented in a substantially perpendicular direction to the length dimension of the tape and embedded in the flexible polymeric matrix material, and wherein
the seam tape has a thickness of 50-200 μm and a strength in the perpendicular direction which is at least 200 N/2.54 cm.
2 . The seam tape according to claim 1 , wherein the flexible polymeric material is a hot melt adhesive that may be the same or different than the hot melt adhesive layer and has a melting point which is no more than 50° C. higher than the melting point of the fibers.
3 . The seam tape according to claim 1 , wherein the flexible polymeric matrix material is a thermoplastic polymer selected from the group consisting of polyamides, copolyamides, polyaminoamides, polyurethanes, polyesters, polyacrylates, polymethacrylates, polyolefins, ethylene/vinyl acetate copolymers and mixtures thereof.
4 . The seam tape according to claim 1 , further comprising a barrier film layer comprising a barrier film with an elastic modulus below 1 GPa.
5 . The seam tape according to claim 4 , wherein the barrier film has a higher melting temperature than the melting temperature of the fibers.
6 . The seam tape according to claim 4 , wherein the barrier film is a thermoplastic polyurethane barrier film.
7 . The seam tape according to claim 1 , wherein the flexible polymeric matrix material is a hot melt adhesive that is the same as the hot melt adhesive layer.
8 . The seam tape according to claim 1 , wherein the tape has an overall stiffness of less than 10,000 N/m.
9 . A product which comprises the seam tape according to claim 1 , wherein the product is selected from the group consisting of backpacks, packs, bags, medical gear, outdoor products, sail cloths, tents, tarps, shelters, clothing, ponchos, foul weather gear, mats, outerwear, jackets, sleeping bags, lift bags, parachutes, large kites, inflatable structures, beams, balloons, packraft, inflatable gear, liferaft, inflatable sculptures, airships, products for space applications, flexible circuits, footwear, inflatables, radomes, tensioned structures and umbrellas.
10 . The seam tape according to claim 1 , wherein the seam tape is adapted to being applied to a curved seam of a product to seal the curved seam, wherein the seam tape exhibits no folds or ceases on an inner radius of the curved seam when sealed.
11 . A product which comprises a curved seam and the seam tape according to claim 1 applied to the curved seam to thereby seal the curved seam, wherein the seam tape exhibits no folds or ceases on an inner radius of the curved seam.
12 . A seam tape having length and width dimensions, the seam tape comprising:
an outer barrier film layer,
at least one fiber layer having outer and inner surfaces, and,
first and second adhesive film layers, the first adhesive film layer being positioned between and in contact with the outer surface of the at least one fiber layer and the outer barrier film layer, and the second adhesive film layer being in contact with the inner surface of the at least one fiber layer, wherein
the at least one fiber layer comprises:
(i) a flexible polymeric matrix material, and
(ii) ultrahigh molecular weight polyethylene (UHMWPE) fibers which are unidirectionally aligned and oriented in a direction substantially perpendicular to the length dimension of the tape and embedded in the flexible polymeric matrix material, and wherein
the seam tape has a thickness of 50-200 μm and a strength in the perpendicular direction which is at least 200 N/2.54 cm.
13 . The seam tape according to claim 12 , wherein each of the first and second adhesive layers comprises a hot melt adhesive.
14 . The seam tape according to claim 13 , wherein the flexible polymeric material is a hot melt adhesive that may be the same or different than the hot melt adhesive of the first and second adhesive layers and has a melting point which is no more than 50° C. higher than the melting point of the fibers.