Claims
- 1. In a process wherein a molten blend of highly crystalline polypropylene (PP) and linear low density polyethylene (LLDPE) is used in producing biconstituent fibers by passing the molten blend through an intensive mixer just before it passes through the fiber dies and is drawn into fibers of a size less than a denier of 30, the improvement which comprises
- using as the LLDPE component one having a melt flow rate in the range of about 12 to about 120 g/10 minutes,
- wherein the ratio of PP/LLDPE in the molten blend is within the range of 3.55 to 0.82, whereby either
- (a) fibers produced from blends having the PP/LLDPE ratio within the range of 3.55 to 1.22 are substantially characterized by having a substantial amount of the LLDPE in the form of fine fibrils randomly arrayed in a PP continuous phase, or
- (b) whereby fibers produced from blends having the PE/LLDPE ratio within the range of 1.22 to 0.82 are substantially characterized by being substantially co-continuous lamellar structures.
- 2. The process of claim 1 wherein the LLDPE has a melt flow rate of about 50.+-.20 g/10 minutes.
- 3. The process of claim 1 wherein the LLDPE has a density in the range of about 0.92 to about 0.94 g/cc.
- 4. The process of claim 1 wherein the fiber has a size in the range of about 0.5 to 15 denier.
- 5. The process of claim 1 wherein the ratio of PP/LLDPE is within the range of 3.55 to 1.22.
- 6. The process of claim 1 wherein the ratio of PP/LLDPE is within the range of 1.22 to 0.82.
- 7. The process of claim 1 wherein the LLDPE is comprised of ethylene copolymerized with an amount of octene sufficient to cause the density to be in the range of about 0.88 to about 0.95 g/cc.
CROSS-REFERENCE TO RELATED APPLICATIONS
This is a continuation of Ser. No. 013,853, now U.S. Pat No. 4,839,228, filed Feb. 12, 1987, which is a continuation-in-part of Ser. No. 909,345 filed Sep. 19, 1986 now abandoned and of Ser. No. 946,562 filed Dec. 24, 1986 now abandoned.
US Referenced Citations (5)
Foreign Referenced Citations (7)
Number |
Date |
Country |
1199746 |
Jan 1986 |
CAX |
0154197 |
Sep 1985 |
EPX |
3544523 |
Jun 1986 |
DEX |
52-072744 |
Jun 1977 |
JPX |
58-011536 |
Jan 1983 |
JPX |
58-206647 |
Dec 1983 |
JPX |
59-041342 |
Mar 1984 |
JPX |
Non-Patent Literature Citations (1)
Entry |
Skoroszewaki-"Parameters affecting processing of polymers and polymer blends"-Plastics & Polymers vol. 40 No. 147 pp. 142-152-Jul. 1972. |
Continuations (1)
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Date |
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Parent |
13853 |
Feb 1987 |
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Continuation in Parts (2)
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Number |
Date |
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Parent |
909345 |
Sep 1986 |
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Parent |
946562 |
Dec 1986 |
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