CONTINUOUS FILAMENT TOW FOR FIBER BATTS
The present invention relates to a continuous filament tow, for use as a filament batt in insulating materials, comprising a continuous solid filament and a continuous hollow filament. The filament batt made from the continuous filament tow has improved compressibility and recovery compared to crimped fiber batts made from a single filament or a single denier. The present invention also includes articles comprising such filament batts and a process by which the continuous filament tow is produced.
1 ) A continuous filament tow comprising: a continuous solid filament, and a continuous hollow filament.
2 ) The continuous filament tow of claim 1 wherein the hollow filament has a void content of from about 10% to about 50%.
3 ) The continuous filament tow of claim 1 wherein the hollow filament has a void content of from about 20% to about 40%.
4 ) The continuous filament tow of claim 1 wherein the solid filament has a denier of from about 1 to about 2.
5 ) The continuous filament tow of claim 1 wherein the solid filament has a denier of from about 1 to about 1.75.
6 ) The continuous filament tow of claim 1 wherein the hollow filament has a denier of from about 1 to about 3.
7 ) The continuous filament tow of claim 1 wherein the hollow filament has a denier of from about 1.2 to about 2.5.
8 ) The continuous filament tow of claim 1 wherein the solid filament is present in a concentration of from 5 weight % to 95 weight %.
9 ) The continuous filament tow of claim 1 wherein the solid filament is present in a concentration of from 30 weight % to 70 weight %.
10 ) The continuous filament tow of claim 1 wherein the hollow filament is present in a concentration of from 5 weight % to 95 weight %.
11 ) The continuous filament tow of claim 1 wherein the hollow filament is present in a concentration of from 30 weight % to 70 weight %.
12 ) A continuous filament tow comprising: a) 30 to 70 wt. % of a continuous solid filament having a denier of about 1 to about 1.5, and b) 70 to 30 wt. % of a continuous hollow filament having a denier of about 1.5 to about 2.25.
13 ) The continuous filament tow of claim 12 wherein the hollow filament has a void content of from about 25% to about 35%.
14 ) The continuous filament tow of claim 1 wherein said solid filament and said hollow filament have the same or different cross sectional shape.
15 ) The continuous filament tow of claim 1 wherein said solid filament and said hollow filament comprise polyester.
16 ) The continuous filament tow of claim 15 wherein said polyester is selected from the group consisting of polyethylene terephthalate, polybutylene terephthalate, polypropylene terephthalate, poly(1,4 cyclohexylene-dimethylene) terephthalate, polyethylene naphthalate, polyethylene bibenzoate, and copolyesters of these.
17 ) A filament batt comprising the continuous filament tow of either claim 1 or 12 .
18 ) The filament batt of claim 17 wherein said batt has both a compressibility and a recovery of about 85% or greater.
19 ) The filament batt of claim 17 wherein said batt has an insulation value greater than about 1.5 clo/ounce.
20 ) The filament batt of either claim 18 or 19 wherein said batt is bonded.
21 ) The filament batt of claim 20 wherein said batt is chemically bonded or thermally bonded.
22 ) The continuous filament tow of either claim 1 or 12 wherein one or both of said filament is coated with a slick finish.
23 ) A filament batt comprising the tow of claim 22 .
24 ) The filament batt of claim 23 wherein said batt has both a compressibility and a recovery of about 85% or greater.
25 ) The filament batt of claim 23 wherein said batt has an insulation value greater than about 1.5 clo/ounce.
26 ) The filament batt of either claim 24 or 25 wherein said batt is bonded.
27 ) The filament batt of claim 26 wherein said batt is chemically bonded or thermally bonded.
28 ) An article comprising the filament batt of either claim 17 or 23 .
29 ) A process for preparing a continuous filament tow comprising a mixture of solid filaments and hollow filaments, said process comprising:
a) melting a polyester polymer,
b) extruding said molten polymer
i) through a spinneret and quenching to form a sub-tow of solid filaments having a natural draw ratio between about 2 and about 5, and
ii) through another spinneret and quenching to form a sub-tow of hollow filaments having a natural draw ratio between about 2 and about 5,
c) combining a mixture of said sub-tows from step b)i) and b)ii) wherein said sub-tows have about the same average, within a range of about 0.2, natural draw ratio, and
d) drawing said mixture of said sub-tows to form a continuous filament tow.
30 ) The process of claim 29 further comprising:
e) heat setting, crimping, drying and packing said continuous filament tow.
31 ) The process of claim 30 wherein a poly(siloxane) composition is applied to said continuous filament tow prior to or after said crimping in step e).