Claims
- 1. A process for producing a synthetic pulp which comprises:
- a. making a composition consisting of
- 1. 50 to 90 parts by weight of polypropylene having a melt flow rate of 30 to 150 as measured at 230.degree.C and under a load of 2.16 kg and
- 2. 50 to 10 parts by weight of low density polyethylene,
- into a film having a thickness of 70 .mu. or less,
- b. uniaxially stretching the resulting film to at least 8 times its original length,
- c. cutting the film thus stretched to lengths of 5 mm or less, and
- d. fibrillating the cut film lengths by passing them through at least two clearances having a distance of 5 mm or less formed between a plurality of linear projections on the inner peripheral surface of a cylindrical casing and the tip ends of at least two sets of a large number of vanes rotating therein at a peripheral speed of 92 - 100.sup.m /sec. whereby a crumpling and disintegrating action mainly by blows and a whirling air stream is brought about to effect fibrillation, and
- e. recovering a synthetic pulp having the following characteristics
- 1. the fibrils being branched in a developed manner from a trunk,
- 2. the trunks and fibrils being extended in various large and small creep or snake-like forms along the longitudinal direction thereof,
- 3. the sizes of the trunks substantially being less than 20 deniers and most of the sizes being less than 5 deniers,
- 4. as the sizes of the trunks are increased, the width is increased as compared with the thickness,
- 5. the length of the trunks being less than 5 mm, and the trunks having substantially uniform fiber lengths for any given length,
- 6. the fibers of each pulp being slightly entangled with one another when collected, and
- 7. the pulp being free from small twisted masses caused by firm entanglement of the fibers and free from molten small particles.
- 2. A process according to claim 1, wherein the low density polyethylene has a melt index of 0.5 to 10 as measured at 190.degree.C and under a load of 2.16 Kg.
- 3. A process according to claim 1, wherein the low density polyethylene has a melt index of 1.0 to 3.0 as measured at 190.degree.C and under a load of 2.16 Kg.
- 4. A process according to claim 1, wherein the uniaxial stretching is carried out at a temperature of 120.degree. - 150.degree.C.
- 5. A process according to claim 1, wherein the fibrillating is carried out in the presence of a surfactant.
- 6. A process according to claim 1, wherein said fibrillating is carried out at least once.
- 7. A process according to claim 2, wherein the uniaxial stretching is carried out under a stretching ratio of 10 - 13 times the original length.
- 8. A process according to claim 5, wherein said surfactant is a dialkyl sulfosuccinate or its salt.
- 9. A process according to claim 5, wherein said surfactant is polyoxyethylene glycol ether.
- 10. A process according to claim 1 wherein the fibrillating is carried out in the presence of a dilute aqueous solution of a surfactant at a concentration of 0.5 to 3% by weight of the solution.
Parent Case Info
This application is a continuation in part of Ser. No. 209,778 filed on Dec. 20, 1971, now abandoned.
US Referenced Citations (9)
Foreign Referenced Citations (2)
Number |
Date |
Country |
6,614,269 |
Oct 1967 |
NL |
1,164,823 |
Sep 1969 |
UK |
Continuation in Parts (1)
|
Number |
Date |
Country |
Parent |
209778 |
Dec 1971 |
|