Warp triplet composite forming fabric
View Patent ↗A forming fabric having a paper side layer and a machine side layer comprises a first set of paper side layer wefts, a second set of machine side layer wefts and a single set of warp yarn triplets. In the fabric weave pattern, each member of each triplet set of warp yarns interweaves with the paper side weft yarns to occupy in sequence segments of an unbroken warp path in the paper side surface, and each triplet in each set of warp yarns interlaces alone with at least one single machine side layer weft yarn. Each segment in the unbroken warp path is separated by at least one paper side layer weft yarn. The machine side layer interlacing points are regularly spaced. After heat setting, the fabrics typically have an air permeability typically from about 7,500 to about 10,500 m 3 /m 2 /hr. Paper products made using these fabrics have enhanced printability.
1. A composite forming fabric having a paper side layer and a machine side layer, which comprises:
(i) a first set of paper side layer weft yarns,
(ii) a second set of machine side layer weft yarns which are larger than the paper side layer weft yarns, and
(iii) a set of triplet warp yarns which contribute to the structure of both the paper side layer and the machine side layer,
which three sets of yarns are woven together according to a repeating pattern wherein:
(a) each member of each triplet set of warp yarns interweaves with the paper side layer weft yarns to occupy in sequence segments of a single unbroken warp path in the paper side layer;
(b) the sequence of segments repeats as part of the repeating pattern;
(c) each segment in the unbroken warp path is separated next segment by at least one paper side layer weft yarn;
(d) each member of each triplet interlaces separately with a single machine side layer weft yarn at least once within the pattern repeat;
(e) within the fabric repeating pattern the number of machine side layer weft yarns between each interlacing point of successive yarns from each triplet of warp yarns is constant; and
(f) within the fabric repeating pattern the path lengths of each member of each triplet set is the same.
2. A forming fabric according to claim 1 wherein the fabric as woven and prior to heat setting has a warp fill of from 100% to 125%.
3. A fabric according to claim 1 wherein the warp and weft yarns are thermoplastic monofilaments.
4. A fabric according to claim 3 wherein the first and second set of weft yarns and the warp yarns are all monofilaments of the same thermoplastic.
5. A fabric according to claim 4 wherein the warp yarns and the first and second sets of weft yarns are all polyethylene terephthalate monofilaments.
6. A fabric according to claim 3 wherein the first set of weft yarns, the second set of weft yarns and the warp yarns is are not all monofilaments of the same thermoplastic.
7. A fabric according to claim 3 wherein the first set of weft yarns comprises at least a first and a second subset of weft yarns and each subset comprises monofilaments of different thermoplastics.
8. A fabric according to claim 3 wherein the second set of weft yarns comprises at least a third and a fourth subset of weft yarns and each subset comprises monofilaments of different thermoplastics.
9. A fabric according to claim 1 wherein the warp yarns are thermoplastic monofilaments having a higher modulus of elasticity than the machine side layer weft yarn thermoplastic monofilaments.
10. A fabric according to claim 9 wherein the ratio of the moduli of elasticity of the warp yarns and the machine side layer weft yarns is about 4:3.
11. A fabric according to claim 1 wherein within each of the first set of weft yarns, the second set of weft yarns, and the warp yarns, the yarns are all of the same size.
12. A fabric according to claim 3 where in the first set and the second set of weft yarns are polyethylene terephthalate monofilaments.
13. A fabric according to claim 1 wherein the second set of weft yarns are yarns chosen from the group consisting of polyethylene terephthalate monofilaments, monofilaments of a blend of polyethylene terephthalate and a thermoplastic polyurethane; polyamide monofilaments and mixtures thereof.
14. A fabric according to claim 13 wherein in the second set of weft yarns the third subset comprises monofilaments of a blend of polyethylene terephthalate and a thermoplastic polyurethane, the fourth subset are yarns chosen from the group consisting of polyethylene terephthalate monofilaments, polyamide monofilaments and mixtures thereof, and the third subset comprises at least 50% of the yarns in the second set in the machine side layer.
15. A fabric according to claim 3 wherein the warp yarns are chosen from the group consisting of polyethylene terephthalate monofilaments, polyethylene naphthalate monofilaments, and mixtures thereof.
16. A fabric according to claim 13 or 14 wherein the polyamide monofilaments are chosen from the group consisting of polyamide-6 and polyamide-6/6 monofilaments.
17. A forming fabric according to claim 1 wherein the fabric has an air permeability, when measured by a standard test procedure, of from less than about 7,500 m 3 /m 2 /hr, to about 11,000 m 3 /m 2 /hr at a pressure differential of 127 Pa through the fabric.
18. A forming fabric according to claim 1 wherein the paper side layer weave design is chosen from the group consisting of a 2×2, 3×3, 3×6 or 4×8 weave design.
19. A fabric according to claim 18 wherein the paper side layer weave design is chosen from the group consisting of a plain 2×2 weave, a 3×3 weave, and a 4×4 weave.
20. A fabric according to claim 1 wherein the machine side layer weave design is chosen from the group consisting of a 3×3, 4×4, 4×8, 5×5, 6×6 or 6×12 weave design.
21. A fabric according to claim 20 wherein the weave design of the machine side layer is chosen from a 3×3 twill, a 6-shed broken twill, or an N×2N design as disclosed by Barrett in U.S. Pat. No. 5,544,678.
22. A fabric according to claim 1 wherein the ratio of paper side layer weft yarns to machine side layer weft yarns is chosen from 1:1, 2:1, 3;2, 5;3 and 3:1.
23. A fabric according to claim 22 wherein the ratio of paper sidle layer weft yarns to machine side layer weft yarns is about 2:1.
24. A fabric according to claim 1 wherein the quotients expressed as Q/P and Q/M, in which Q is the total number of sheds, P is the number of sheds required to weave the paper side layer design, and M is the number of sheds required to weave the machine side layer design are integers.
25. A fabric according to claim 3 wherein the warp yarns are polyethylene naphthalate, the first set of weft yarns are polyethylene terephthalate, and in the second set of weft yarns the third subset comprises monofilaments of a blend of plyethylene terephthalate and a thermoplastic polyurethane and the fourth subset comprises polyamide monofilaments.
26. A fabric according to claim 3 wherein the warp yarns are polyethylene terephthalate, the first set of weft yarns are polyethylene terephthalate, and in the second set of weft yarns the third subset comprises monofilaments of a blend of plyethylene terephthalate and a thermoplastic polyurethane and the fourth subset comprises polyamide monofilaments.