JPH02160909A - Flash spinning - Google Patents

Abstract

PURPOSE: To provide a flash spinning method free from environmental pollution problem in production process by using a specific halogenated hydrocarbon as a solvent for the flash spinning of a polyethylene dissolved in a halogenated hydrocarbon spinning liquid. CONSTITUTION: A spinning liquid obtained by dissolving a polyethylene in a halogenated hydrocarbon spinning liquid, having a polyethylene concentration of 10-20 wt.% and maintained at 130-210 deg.C and 3,000 psi pressure is spun by flash spinning to a region having temperature and pressure lower than the above levels to obtain a plexifilamentary film-fibril strand. In the above process, 1,1-dichloro-2,2,2-trifluoroethane or 1,2-dichloro-1,2,2-trifluoroethane is used as the halogenated hydrocarbon to prevent the destruction of the ozonosphere of the earth. The above solvent may be incorporated with <=15 wt.% of a cosolvent such as cyclohexane.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to flash spinning of polymeric film-fibril yarns. More particularly, the present invention relates to improvements in such processes that allow flash spinning of yarns from liquids that, if released into the atmosphere, do not have a detrimental effect on the earth's ozone.

In summary, according to the present invention, a small number of halogenated hydrocarbons present a greatly reduced ozone depletion risk when released into the atmosphere compared to the halogenated hydrocarbons currently used commercially for producing yarn. An improved method for flash spinning fiber-forming polyolefin plexifilamentary film-fibril yarns from halogenated hydrocarbon liquids is provided. Halogenated hydrocarbons suitable for this purpose are l
.

1-dichloro-212,2-trifluoroethane.

Blades and White
U.S. Pat. No. 3,081,519 describes a flash-spinning process for producing prekin filamentary film-fibril yarns from fiber-forming polymers. A solution of the polymer in a liquid that is a non-solvent for the polymer at or below the normal boiling point of the liquid can be prepared at a temperature above the normal boiling point of the liquid and at a pressure at or above the autogenous pressure, at a lower temperature and substantially Extrusion into a medium of low pressure. This flash spinning evaporates the liquid and thus cools the extrudate to produce a polymeric plexifilamentary film-fibril yarn. Suitable polymers are crystalline polyhydrocarbons such as polyethylene and polypropylene.

According to Blaise and White, liquids suitable for flash spinning (a) have a boiling point of at least 25° C. below the melting point of the polymer; (b) do not substantially react with the polymer at the extrusion temperature; C) Pressures and temperatures mentioned in the patent (
That is, these extrusion temperatures and pressures are respectively 165~
(b) should dissolve less than 1% of the polymer at or below normal boiling points; and provide rapid phase separation upon extrusion. A solution should be produced that forms a polymer phase that contains insufficient solvent to react and plasticize the polymer. Depending on the particular polymer used, the following liquids are useful in the flash spinning process: aromatic hydrocarbons such as benzene, toluene, etc.; aliphatic hydrocarbons such as butane, pentane, hexane, heptane, octane, and their isomers. alicyclic hydrocarbons such as cyclohexane; unsaturated hydrocarbons: halogenated hydrocarbons such as methylene chloride, tetrachloride hydrocarbons, chloroform, ethyl chloride, methyl chloride; alcohols; esters: ethers; ketones; nitriles; amides ;fluorocarbon; sulfur dioxide; carbon dioxide; -tromethane;
water; and mixtures of the liquids mentioned above. This patent also schematically illustrates certain theories to help establish optimal spinning solutions for obtaining plexifilamentary yarns.

Blaze and white are prepared by adding dissolved gas such as nitrogen, carbon dioxide, helium, hydrogen, etc. to the flash spinning solution.
It states that it may contain methane, propane, butane, ethylene, propylene, butane, etc.

Gases with low solubility, i.e. 7% in the polymer solution under spinning conditions
Those that dissolve up to the following concentrations are suitable for fibrillation of plexifilaments. Conventional additives such as antioxidants, UV stabilizers, dyes, pigments, etc. can also be added to the solution before extrusion.

Anderson and Rom
U.S. Pat. No. 3,22,7,794 to Ano) discloses a scheme similar to Blaise and White for selecting conditions for spinning plexifilamentary yarns. Linear polyethylene in trichlorofluoromethane 1
A graph of spinning temperature versus spinning pressure is presented for 0-16 wt% solutions. This patent also describes the preparation and let-down of a 14% by weight solution of high density linear polyethylene in trichlorofluoromethane at a temperature of about 18,500 and a pressure of about 1,640 psig.
The commercial flash spinning of polyethylene into plexifilamentary film-fibril yarns at exactly similar temperatures, pressures and concentrations is described in detail. This has then been made into sheet structures.

Trichlorofluoromethane is a very useful solvent for the flash spinning of polyethylene plexifilamentary film-fibril yarns, and has been the solvent used in the commercial production of polyethylene plexifilamentary yarns. , the dissipation of such halogenated hydrocarbons into the atmosphere has been pointed out as a major source of global ozone depletion. For a general discussion of ozone depletion, see, for example, P.

S. Zurer, “Search for replacements for ozone-depleting halogenated hydrocarbons intensifies (Search Int.
gnsifices for Alternatives
to Ozone-Depleting Haloca
rbons) J, Chemical & Engineer News (Chemical & Engineer)
ing News), pp. 17-20 (February 8, 1988).

A convenient test for determining whether a given solvent is suitable for flash spinning a given polymer is described in U.S. Pat. No. 3,655 to Woodell.
, No. 498. This test method is widely used by the world's largest manufacturers of polyethylene flash-spun products to determine the suitability of trifluorochloromethane solvent replacements for the production of plexifilaments. In this test, a mixture of polymer and an amount of solvent calculated to give an approximately 10% solution by weight is sealed in a thick-walled glass tube (the mixture is approximately Z of the volume of the tube).
~%), and the mixture is heated under autogenous pressure. Test temperatures typically range from 100°C to just below the critical temperature of the liquid being tested. Uradel indicates that the solvent power is too low if a single-phase flowable solution does not form in the tube at any temperature below the critical temperature of the solvent, Tc (or the decomposition temperature of the polymer, whichever is lower). It has said. At the other extreme, if a single-phase solution forms at a temperature below Tc but does not convert into two liquid phases when the solution is heated to a higher temperature (but below Tc), then the solvent power is too expensive. Solvents whose inherent solvent power does not fall within these extremes may be made suitable by dilution with a non-solvent or by addition of a good solvent, if appropriate. After selecting a suitable solvent or solvent mixture, the single phase and two liquid phase boundary behavior of the solvent or mixture may be determined as a function of temperature and pressure at different polymer concentrations as described by Anderson and Romano, supra.

It is an object of the present invention to provide an improved method for flash spinning fiber-forming polyolefin plexifilamentary film-fibril yarns in which the solvent should not be at risk of depletion of the earth's ozone.

The present invention involves dissolving polyethylene in a hydrohalogenated hydrocarbon spinning liquid to produce a spinning solution containing polyethylene at 10-20% by weight of the solution at a temperature in the range of 130-210°C and a pressure of 3000 psi or more; During the flash spinning of plexifilamentary film-fibril yarns, this solution is flash spun into an area of substantially lower temperature and pressure.
The flash spinning process is provided by selecting from the group consisting of 1-dichloro-2,2,2-trifluoroethane and 1,2-dichloro-1,2,2-trifluoroethane.

The present invention involves dissolving polyethylene in a hydrohalogenated hydrocarbon spinning liquid to produce a spinning solution containing polyethylene at 10 to 20% by weight of the solution at a temperature in the range of 130 to 21 O<0>C and a pressure of 1800 psi or more; During the flash spinning of plexifilamentary film-fibril yarns, this solution is flash spun into an area of substantially lower temperature and pressure.
The flash spinning method is provided for selecting from the group consisting of ゜1-dichloro-2,3-difluoroethane and t/1゜2-dichloro-1,1-difluoroethane.

The present invention involves dissolving polyethylene in a hydrohalogenated hydrocarbon spinning liquid to produce a spinning solution containing polyethylene at 10 to 20% by weight of the solution at a temperature in the range of 130 to 21 O<0>C and a pressure of more than 2000 psi; During the flash spinning of plexifilamentary film-fibril yarns, this solution is flash spun into an area of substantially lower temperature and pressure.
゜■-Dichloro-1-fluoroethane is provided.

The present invention involves dissolving polypropylene in a halogenated hydrocarbon spinning liquid, and adding polyethylene to 10 to 20% by weight of the solution.
A plexifilamentary film-fibril yarn is produced at a temperature in the range of 130 to 210° C. and a pressure above 1500 psi, and the solution is flash spun to a region of substantially lower temperature and pressure. During flash spinning, the halogenated hydrocarbon was mixed with 1°l-dichloro-2,2,2-trifluoroethane,
1.2-dichloro-1,2,2-trifluoroethane,
l,1-dichloro-2,2-difluoroethane, l,2
- dichloro-1,1-difluoroethane and 1,1-dichloro-1-fluoroethane.

The present invention involves dissolving the fiber-forming polyolefin in a halogenated hydrocarbon spinning liquid at a temperature in the range of 130-210°C and a pressure of 1 OOpsi or more, provided that the spinning liquid accounts for 2-25% of the total weight of the spinning liquid. containing a hydrocarbon co-solvent corresponding to , to produce a spinning solution containing the fiber-forming polyolefin at 10-20% by weight of the solution;
During the flash spinning of the flexifilamentary film fibril yarn, which is then flash spun to a region of substantially lower temperature and pressure, the / 1.2-dichloro-1,2゜2-trifluoroethane, 1. l-dichloro-2゜2-difluoroethane,
1.2-dichloro-1,1 difluoroethane, and 1.
Provided is a method for flash spinning selected from the group consisting of 1-dichloro-1 fluoroethane.

The present invention provides 10 to 20% by weight of polyolefins forming fibers and 1,1-dichloro-2,2,2-trifluoroethane, 1,2-dichloro-1,22-trifluoroethane, 1,1-dichloro- 2゜2-difluoroethane, 1
, 2-dichloro-1.1 difluoroethane, and 1.1
A novel solution is provided which consists essentially of 90-80% by weight of a liquid containing a halogenated hydrocarbon selected from the group consisting of -dichloro-1fluoroethane.

The present invention uses 10 to 20% by weight of polyolefins forming fibers and 1,1-dichloro-2,2,2-trifluoroethane, 1,2-dichloro-1,2゜2-trifluoroethane, 1.1-dichloro-2,2,2-trifluoroethane, Dichloro-2゜2-difluoroethane,
1.2-dichloro-1,1 difluoroethane, and 1.
A novel solution is provided consisting essentially of 90-80% by weight of a halogenated hydrocarbon liquid selected from the group consisting of 1-dichloro-1fluoroethane.

As used herein, "polyolefin" means any primarily saturated open chain polymeric hydrocarbon consisting solely of carbons and hydrogens. Typical polyolefins include, but are not limited to, polyethylene, polypropylene, and polymethylpentene. For convenience,
Polyethylene and polypropylene are suitable polyolefins for use in the process of the invention.

As used herein, "polyethylene" refers to a homopolymer of ethylene, as well as a polyethylene containing at least 85% of the repeating units.
Also includes copolymers in which is an ethylene unit. Suitable polyethylenes have an upper melting range of about 130-135°C, 0
．． Densities ranging from 94 to 0.98 cm3 and from 0.1 to
It is a homopolymer linear polyethylene having a melt index of 6.0 (measured under ASTM D-1238-57T, Condition E).

"Polypropylene" includes not only homopolymers of propylene, but also copolymers in which at least 85% of the repeating units are propylene units.

"Plexifilamentary film-fibril yarn" as used herein
ryfilm-fibril 5Lrands) J is a large number of thin, ribbon-like films of random length and average thickness of about 4 microns or less generally arranged coaxially with the longitudinal axis of the thread. - means a thread characterized as a three-dimensionally integrated network of fibrillar elements. The film-fibril elements combine and separate intermittently at irregular intervals at various locations throughout the length, width, and thickness of the yarn to form a three-dimensional network. Such threads are described in U.S. Patent No. 3.08 to Blaise and White.
No. 1,519 and Anderson and Raman, US Pat. No. 3,227,794.

The present invention provides an improvement over known processes for producing plexifilamentary film-fibril yarns of fiber-forming polyolefins from halogenated hydrocarbon spinning solutions containing 10-20% by weight of fiber-forming polyolefins. A fiber-forming polyolefin, such as linear polyethylene, is dissolved in a spinning liquid containing a halogenated hydrocarbon to produce a spinning solution containing linear polyethylene at 10-20% by weight of the solution, and then heated at 130-210°C. The spinning process is carried out at temperatures and pressures greater than the spontaneous pressure of the spinning liquid in a region of substantially lower temperatures and pressures.

The main improvement of the present invention is that 1.1-dichloro-2,2,2-trifluoroethane (
HC-123), 1,2-dichloro-1,2,2-trifluoroethane (
HC-123a), 1,1-dichloro-2,2-difluoroethane (Hc-
132a), 1,2-dichloro-1,1-difluoroethane (HC-
132b), and 11-dichloro-1-fluoroethane (HCl 4 l
b) Requires a halogenated hydrocarbon selected from the group consisting of:

The symbols in parentheses above are used herein as abbreviations for the chemical formulas of the halogenated hydrocarbons. The following table shows the known normal atmospheric boiling points (Tbp), critical temperatures (Tcr) and critical pressures (Pcr) for selected hydrocarbons and some prior art solvents. The table also indicates in the column labeled "Solubility" whether a 10% polyethylene solution can be formed in the halogenated hydrocarbon at temperatures from 130 DEG C. to about 225 DEG C. and under autogenous pressure.

Tlzs, I Tcr, I Pcr, psiap
c-12328,7185550 HC-123a 2g IC-132a 60 HC-132b 46.8 1(C-141b 32 Trichlorofluoromethane 23.8 198.0 63
9.5 High methylene chloride 39.9
237.0 g94.7 Hyhexane
68.9 234.4 436.5
High cyclohexane 80.7 280.4
590.2 High It is noted that the five suitable hydrocarbons listed above represent a very special and small group of halogenated hydrocarbons that are suitable for use in the present invention. There are hundreds of halogenated hydrocarbons to choose from. The conventional method of screening liquids (i.e., by using the polyethylene dissolution test under autogenous pressure described above) is that the conventional solvents described above are The halogenated hydrocarbons found useful in the present invention are unsuitable because they do not dissolve polyethylene under autogenous pressure, whereas they form solutions with polyethylene under autogenous pressure.

Furthermore, compared to past flash spinning fluids, none of the halogenated hydrocarbons of the present invention form a single phase solution with polyethylene under pressures below 1500 psia at the required concentrations and temperatures. These halogenated hydrocarbons, of course, also possess certain properties possessed by known fiber-forming polyolefin flash spinning fluids. For example, these halogenated hydrocarbons also do not substantially react with the polymer at extrusion temperatures. These halogenated hydrocarbons are solvents for fiber-forming polyolefins under certain conditions, and at or below their normal boiling point they can
% and undergoes rapid phase separation upon extrusion to produce a solution that forms a polymer phase containing insufficient solvent to plasticize the polymer.

In addition to the properties described above, halogenated hydrocarbons and solutions suitable for use in the process of the present invention (1) have boiling points in the range of 0 to 80°C; and (2) are incompletely fluorinated and/or chlorinated, (3) has low flammability, (4) has an adequate heat of vaporization to allow rapid cooling of the plexifilament when produced by flash spinning, and (5) is suitable for flash spinning. (6) have suitable thermal and hydrolytic stability for use in conventional spin bonding methods for forming sheets of plexifilaments [e.g. -(St
(7) has a sufficiently high electrostatic breakdown potential in the gas phase so that it can be used in U.S. Pat.
A 10% by weight solution of polyethylene in liquid cannot be formed in a single phase at any pressure below 500 psia. Particularly in the case of HCl23 and Hc-123a, such solutions of polyethylene can be formed in halogenated hydrocarbon liquids only at pressures above 3000 psi, and in the case of HC-132a and HC-132b, such solutions of polyethylene Solutions can form in halogenated hydrocarbon liquids only at pressures above 1800 psi; and in the case of I-I C-141b, such solutions of polyethylene can form in halogenated hydrocarbon liquids only at pressures above 2000 psi. can be generated. Such a solution of polypropylene is 1500p
can form in the halogenated hydrocarbon spinning liquid of the present invention only at pressures above si.

Satisfactory solutions of polymer and halogenated hydrocarbon can be produced at pressures greater than 1000 psi only when high solvent power co-solvents are present in the halogenated hydrocarbon spinning liquid.

It has been discovered that the combination of halogenated hydrocarbon properties is matched by substantially only the five halogenated hydrocarbons mentioned above. To perform as well as any of these five halogenated hydrocarbons, other halogenated hydrocarbons must also be used to flash-spun high quality pre-filled filamentary puylum-fibril yarns of fiber-forming polyolefins. Substantially all of those characteristics would have to be met to be suitable.

Even among the five halogenated hydrocarbons suitable for use in the process of the invention, care must also be taken with these halogenated hydrocarbons in order to avoid certain adverse properties that may be present. For example, HC-123a, HC-132a
, HC-132b and HC-141b, excessive heating times are avoided to minimize decomposition from dehydrogenation or hydrolysis of the halogenated hydrocarbon. In the case of HCl32b, care must be taken as this chemical is reproductively toxic to male animals. HC-123 is a preferred halogenated hydrocarbon for use in the present method since it is relatively free of all of the stability and toxicity issues discussed above.

In preparing the solution of fiber-forming polyolefin in halogenated hydrocarbon liquid of the present invention, the mixture of fiber-forming polyolefin and halogenated hydrocarbon is raised to a temperature of 130-210<0>C. If the polyethylene is a polyolefin, the mixture is heated under a pressure of 200 Qpsi or more when the halogenated hydrocarbon is HC-141b, and 3000 ps when the halogenated hydrocarbon is HC-123 or HC-123a.
under pressures above si, and halogenated hydrocarbons
132a or HC-132b, place under pressure of 1800 ps1 or more. If polypropylene is used, the pressure will be 1500 ps regardless of the halogenated hydrocarbon selected.
It is greater than or equal to i. The mixture described above is maintained under the necessary pressure until a liquid solution of the fiber-forming polyolefin is formed. Normally, a maximum pressure of 100QQpsi or less is satisfactory.

After the fiber-forming polyolefin is dissolved, the pressure is reduced somewhat and the mixture is flash spun to form the desired high quality plexifilamentary yarn structure.

The concentration of fiber-forming polyolefin in the spinning liquid is typically 10% based on the total weight of fiber-forming polyolefin and liquid.
It is in the range of ~20%.

The spinning solution preferably consists of a halogenated hydrocarbon liquid and a fiber-forming polyolefin. However, if lower pressures for solution preparation and spinning are desired, the spinning solution can contain a second liquid or cosolvent for the fiber-forming polyolefin.

If the co-solvent contains hydrocarbon solvents such as cyclohexane, toluene, chlorobenzene, hexane, pentane, 3-methylpentane, etc., the concentration of the co-solvent in the mixture of halogenated hydrocarbon and co-solvent will generally be lower than the potential flammability. It corresponds to 2 to 25% by weight, preferably not more than 15% by weight, in order to minimize sexual problems. However, when methylene chloride is used as a co-solvent, the concentration of methylene chloride in the halogenated hydrocarbon/co-solvent mixture (ie, free of fiber-forming polyolefin) is generally from 5 to 50% by weight.

Customary flash spinning additives can be introduced into the spinning mixture by known techniques. These additives function as UV stabilizers, antioxidants, fillers, dyes, etc.

The various properties and properties referred to in the discussion above and in the examples below were determined in the following manner.

The solubility of polyethylene and polypropylene under special spontaneous conditions is also described in the last section of the ``Description of the Prior Art'' section of Uradel's U.S. Pat. Measured by tube test.

Prequin filamentary film produced in Examples
The quality of the fibril threads was evaluated subjectively.

A rating of "5" indicates that the yarn had better fibrillation than is normally achieved in commercial manufacture of spinbonded sheets made from such flash-spun polyethylene yarns. A rating of "4" indicates that the product was as good as commercial flash spun yarn. A rating of "3" indicates that the yarn was not as good as a commercial flash spun yarn. A rating of "2" indicates a very poorly fibrillated and inadequate yarn.

"1" indicates that no yarn is produced. A rating of "3" is the lowest possible standard for use in the method of the present invention. Commercial photoproducts include trichlorofluoromethane, substantially as described in Lee, U.S. Pat. Made from approximately 12.5% linear polyethylene.

The surface area of the plexifilamentary film-fibril yarn product is another measure of the degree of fibrillation and fineness of the flash spun product.

The surface area is S, Brunaer, P
,H.

Emmett and E. Teller
r), J.

Am, Chem, Soc,
60.309-319 (1938) and is reported as m2/2.

The tenacity of flash spun yarns is determined on an Instron tensile tester. This yarn runs at 70°F and 65% relative humidity.
Adjust and test.

The denier of the yarn is determined from the weight of a 15 cm test length of yarn.

The sample is then mounted on the Instron testing machine with up to 10 turns per inch. A gauge length of 1 inch and a draw speed of 60%/min are used. Fracture toughness is reported in 2/denyl (gpd).

The invention is illustrated in the following examples using a batch process on relatively small scale equipment. Such batch processes are described, for example, in Anderson and Romano, U.S. Pat. No. 3,227,7.
It is possible to scale up and convert to continuous flash spinning, which can be carried out in equipment of the type disclosed in No. 94. In the Examples and Tables, the methods of the invention are defined by Arabic numerals. Methods shown in uppercase letters are control methods other than the present invention.

EXAMPLES For each of Examples 1-25 and Control Examples A and B, high density linear polyethylene with a tart index of 0.76 was flash spun into acceptable plexifilamentary film-fibril yarns in accordance with the present invention ( However, in Example 7, low density linear polyethylene with a melt index of 26 was used).

Blends of halogenated hydrocarbon and fiber-forming polyolefin were prepared and flash spun using two types of equipment. In Examples L5 and 16, devices indicated by "■" were used. For all other Examples and Control Examples, an apparatus designated r[J was used.

The device "■" has a capacity of 50 cm3 with a cylindrical piston at one end suitable for applying pressure to the contents of the container.
A high-pressure device comprising a cylindrical container. The other end of the vessel is equipped with a spinneret assembly having an orifice 0.030 inch in diameter and 0.060 inch in length and quick acting means for opening and closing the orifice. Means are also provided for measuring the pressure and temperature within the vessel.

In operation, a vessel is charged with a fiber-forming polyolefin and a halogenated hydrocarbon. This preparation is heated under high pressure (e.g. 4
500psi). The contents are heated to the desired temperature (eg, 140° C.) for about 1 hour to form a solution, which is then “mixed” by applying pressure about 10 times. The pressure is then reduced to the desired pressure for spinning and the valve of the spinneret oriais opened. The resulting flash spun product is then collected.

The device rl[J comprises a pair of high-pressure cylindrical vessels each equipped with a piston for applying pressure. The vessels were each similar to the cylindrical vessels of device "■", but rather than each vessel having an orifice assembly, the two were connected to each other by a transfer conduit. The transfer conduit includes a series of fine sieves intended to mix the contents of the device by forcing the contents from one cylinder to another through the transfer conduit. A spinneret assembly having a 0.030 inch diameter oriice is connected to a transfer conduit with quick-acting means for opening and closing the oriice. Means for measuring pressure and temperature are also established within the vessel. In operation, the apparatus is charged with a fiber-forming polyolefin and a halogenated hydrocarbon and high pressure is applied to the charge.

The contents are then heated to the desired temperature for about one and a half hours, during which time a pressure differential of about 50 psi is alternately applied between the two cylinders, and the contents are recycled from one cylinder to the other through a transfer conduit. , and return feeding to achieve mixing and effective production of the solution.

The desired pressure for spinning is then set and the spinneret orifice is opened. The resulting flash spun product is then collected.

All Examples and Controls were prepared by using the special conditions and special ingredients shown in the table below depending on the equipment used.
It was done in the same way. The table below also records the properties of the yarn produced by flash spinning.

In Table 1, Examples 1-7 illustrate the use of different halogenated hydrocarbons suitable for the process and solutions of the invention.

Control Examples A and B show the use of some of the same halogenated hydrocarbons, but under conditions that do not allow for satisfactory yarn production.

Table ■ Table Example number Equipment Polyethylene concentration 9% by weight Solvent: HC Mixing temperature 2°C Pressure + psig Spinning temperature 9°C Pressure + psig Yarn product denyl toughness, gpd Quality ■ ■ 14.4 3.25 ■ 2.91 12 12 12 12 11.4
12 12123 132b 132b
141b 123a 132a 1
32bns* 476ns 5
98 nm** nm nmn5
3.03ns 2.8n
m nm nm1 4.5
1 4 3 4 3 In Table 3, Examples 8-25 illustrate the use of various co-solvents with halogenated hydrocarbons.

Table 2 mun u Example number Apparatus Polyethylene concentration 2% by weight Solvent: H-C 32b % by weight Mixing temperature 9°C Pressure + psig Spinning temperature. C pressure, psig photoproduct denyl toughness, gpcl surface area m2/2 quality 2.74 2,58 2.4337.8
49,6 63.14.5 4.5 4 4.5 Apparatus I I [II Polyethylene concentration 1% by weight 1.1.4 12 12 Solvent: H-CI23 123 123 Co-solvent Hentane Hexane Chlorobenzene Weight% 13.
1 20 6.7 Mixing temperature, °C 140 140 140 Pressure, psig 4200-3700 2700
2600 spinning temperature,'(! 170 170 170
Pressure, psig 3000 2900 2
800 yarn product quality 4 5 4 Table ■ (Continued) Equipment Polyethylene concentration 9% by weight Solvent: H-C Co-solvent % by weight Mixing temperature 1°C Pressure + psig Spinning temperature 0C Pressure, psig Photoproduct denyl toughness, gpd Quality Surface area ■ 6H12 13,3 ■ ■ I2 C6B , □ ■ Toluene 13.3 2900 2500 2900 '200
02.3 1.96 2.41 1.7
05 5 4.5 4.534
．． 9 28.0 15.9 25.6 Equipment Polyethylene concentration 9% by weight Solvent:] (-C Co-solvent % by weight Mixing temperature 1°C Pressure, psig Spinning temperature 1°C Pressure, psig Photoproduct denyl toughness, 1EI) d Surface area m"I1 Quality ■ ■ ■ ~4700 ~4700 ~40004.61
2,93 4.2234.2 36.4
52.9 Table ■ (continued) Example number Equipment Polyethylene concentration 1% by weight Solvent: l-1-C Co-solvent weight% Mixing temperature 1°C Pressure + psig Spinning temperature 9°C Pressure, psig Ice product denyl toughness, gpd Surface area m2/2 Quality C) 12C1□ 32.5 1800 1800 ~5000 4000
1575 1575 ~5000 ~365
0486.8 399.2 707 549
2.67 2.4.3 1.79 '2.
9429.7 36,2 34,9 30
．． 55 4.5 4 4*
rnsJ means no thread production.

** rnmJ means no measurement was performed.

+ C6H12 is cyclohexane.

In Table 1, Example 26 shows that well fibrillated plexifilaments can be obtained from other types of polyolefins using the present invention. The equipment and method used in this example included Hercules, Inc., in place of polyethylene.
Wilmington, De) from the product name "Puo7"
The examples were the same as those in Table 1 except that Melt 70 0.4 isotactic polypropylene, commercially available as Profax 6823J, was used. Additionally, high mixing temperatures were used due to the higher melting point of the polymer. The conditions used and the properties of the fibers obtained are summarized in Table 2. The polymer mixture contained 3.6% by weight of Irganox l 010 C based on the polymer.
Ciba-Geigy Corp.'s trade name for high molecular weight sterically hindered polyphenols was contained as an antioxidant.

Table m Example number Apparatus Polyethylene concentration 1% by weight Solvent: HC Mixing temperature 1°C Pressure + psig Spinning temperature 1°C Pressure + psig Ice product denyl toughness, gpd Quality ■ 1.23 Features and embodiments of the invention are as follows 1. Polyethylene is dissolved in a halogenated hydrocarbon spinning liquid to prepare a spinning liquid containing polyethylene in an amount of 10 to 20% by weight of the solution.
In the flash spinning of plexifilamentary film-fibril yarns produced at temperatures in the range of 130 to 210' O and pressures above 3000 psi, the solution is flash spun to substantially lower temperatures and fJ ranges of E forces. , wherein the halogenated hydrocarbon is selected from the group consisting of 1,1-dichloro-2,2,2-trifluoroethane and 1°2-dichloro-1,2,2-trifluoroethane.

2. Polyethylene is dissolved in a halogenated hydrogen spinning liquid, and the spinning liquid containing polyethylene at 10 to 20% by weight of the solution is heated at a temperature in the range of 130 to 210 °C and 18
During the flash spinning of plexifilamentary film-fibril yarns produced at pressures above 0.00 psi and flash spinning this solution to a region of substantially lower temperatures and pressures, halogenated hydrocarbons are
-dichloro-2,3-difluoroethane and (, l' l
, 2-cyclo-1,1-difluoroethane.

3. Polyethylene is dissolved in a halogenated hydrocarbon spinning liquid, and the spinning liquid containing polyethylene at 10-20% by weight of the solution is heated at a temperature in the range of 130-210°C and 200°C.
During the flash spinning of plexifilamentary film-fibril yarns produced at pressures above 0 psi and flash spinning this solution to a region of substantially lower temperatures and pressures, 1.
The flash spinning method uses 1-dichloro-1-fluoroethane.

4. Polypropylene is dissolved in a halogenated hydrocarbon spinning liquid, and a spinning liquid containing polyethylene at 10-20% by weight of the solution is prepared at a temperature in the range of 130-210°C and 15% by weight of the solution.
During flash spinning of plexifilamentary film-fibril yarns produced at pressures greater than 0.00 psi and flash spinning this solution to an area of substantially lower temperature and pressure, halogenated hydrocarbons are added to 1.1 psi.
Dichloro-2,2,2-trifluoroethane, 12-dichloro-1,2,2-trifluoroethane, 1,1-dichloro-2,2-difluoroethane, 1゜2-dichloro-1,1-difluoroethane and l.

The flash method is selected from the group consisting of 1-dichloro-1-fluoroethane.

5. Polyolefin to form fibers is added to a halogenated hydrocarbon spinning liquid at a temperature in the range of 130-210°C and 1OO
The fiber-forming polyolefin is dissolved at pressures greater than Opsi, provided that the spinning liquid contains a hydrocarbon co-solvent representing 2-25% of the total weight of the spinning liquid, so that the polyolefin forming the fiber is
During the flash spinning of flexifilamentary film-fibril yarns, a spinning solution containing 0 to 20% by weight of halogenated hydrocarbons is produced, which is then flash spun to a region of substantially lower temperature and pressure. 1-dichloro-2,2,2-trifluoroethane, 1,2-dichloro-1,2,2-trifluoroethane,
The flash spinning method is selected from the group consisting of 1.1-dichloro-2,2-=42 difluoroethane, 1,2-dichloro-1,1-difluoroethane, and 1,1-dichloro-1-fluoroethane.

6. The method of 5 above, wherein the co-solvent is selected from the group consisting of 3-methylpentane, cyclohexane, toluene, pentane, hexane and chlorobenzene.

7. The method of 6 above, wherein the co-solvent represents at most 15% of the total weight of the spinning liquid.

8. The fiber-forming polyolefin is added to a halogenated hydrocarbon spinning liquid at a temperature in the range of 130-210°C and 100°C.
The fiber-forming polyolefin is dissolved at a pressure greater than 0 psi, provided that the spinning liquid contains methylene chloride representing 5 to 10% of the total weight of the spinning liquid, so that the fiber-forming polyolefin is
During the flash spinning of flexifilamentary film-fibril yarns, producing a spinning solution containing ~20% by weight, which is then flash spun into a region of substantially lower temperature and pressure, the halogenated hydrocarbon -dichloro-2,2,2-trifluoroethane,
1.2-dichloro-1,2,2-triple olethane,
1,1-dichloro-2,2-difluoroethane, l,2
-dichloro-1,1-difluoroethane, and 1,1-
The flash spinning method selected from the group consisting of dichloro-1-fluoroethane.

9. The halogenated hydrocarbon is 1,1-dichloro-2,2,
2-trifluoroethane, the method of 1 above.

10. 5.6 above, where the polyolefin is polyethylene
．． 7. Method 8 or 9.

11. 5 above, wherein the polyolefin is polypropylene.
Method 6.7.8 or 9.

12. 10-20% by weight of polyolefin forming fibers
and 1.1-dichloro-2,2,2-trifluoroethane, 1.2-dichloro-1,2,2-trifluoroethane, l,1-dichloro-2,2-difluoroethane, 1.
2-dichloro-1,1-difluoroethane, and 1.1
- A solution consisting essentially of 90 to 80% by weight of a liquid containing a halogenated hydrocarbon selected from the group consisting of dichloro-1-fluoroethane.

13. 10-20% by weight of polyolefin forming fibers
and 1,1-dichloro-2,2,2-trifluoroethane, 1,2-dichloro-1.2.2 trifluoroethane, 1.1-dichloro-2,2 difluoroethane, 1.2
-dichloro-1,1-difluoroethane, and 1,1-
A solution consisting essentially of 90-80% by weight of a halogenated hydrocarbon liquid selected from the group consisting of dichloro-1-fluoroethane.

14. 1 above, wherein the liquid contains a halogenated hydrocarbon and a hydrocarbon co-solvent corresponding to 2 to 25% of the total weight of the co-solvent.
Solution of 2.

15. The solution of 12 above, wherein the liquid contains a halogenated hydrocarbon and methylene chloride as a co-solvent corresponding to 5 to 50% of the total weight of the co-solvent.

16, halogenated hydrocarbon is 1.1-dichloro2.2.
The solution of 12.13.14 or 15 above which is 2-trifluoroethane.

17. The solution of 12.13.14.15 or 16 above, wherein the m-fiber-forming polyolefin is 1/7 polyethylene.

18. The solution of 12.13.14.15 or 16 above, wherein the fiber-forming polyolefin is polypropylene.

Patent Applicant: E.I. Dupont des Nimois Books & Company

Claims (1)

[Claims] 1. Polyethylene is dissolved in a halogenated hydrocarbon spinning liquid, and a spinning liquid containing polyethylene in an amount of 10 to 20% by weight of the solution is prepared at a temperature in the range of 130 to 210°C and at 300°C.
During flash spinning of plexifilamentary film-fibril yarns produced at pressures greater than 0 psi and flash spinning this solution to a region of substantially lower temperature and pressure, halogenated hydrocarbons are
Dichloro-2,2,2-trifluoroethane and 1,2
- dichloro-1,2,2-trifluoroethane. 2. Polyethylene is dissolved in a halogenated hydrocarbon spinning liquid, and the spinning liquid containing polyethylene at 10-20% by weight of the solution is heated at a temperature in the range of 130-210°C and 180°C.
During flash spinning of plexifilamentary film-fibril yarns produced at pressures greater than 0 psi and flash spinning this solution to a region of substantially lower temperature and pressure, halogenated hydrocarbons are
The flash spinning method is selected from the group consisting of dichloro-2,3-difluoroethane and 1,2-dichloro-1,1-difluoroethane. 3. Polyethylene is dissolved in a halogenated hydrocarbon spinning liquid, and the spinning liquid containing polyethylene at 10-20% by weight of the solution is heated at a temperature in the range of 130-210°C and 200°C.
1, as halogenated hydrocarbons during flash spinning of plexifilamentary film-fibril yarns produced at pressures above 0 psi and flash spinning this solution to a region of substantially lower temperatures and pressures.
The flash spinning method uses 1-dichloro-1-fluoroethane. 4. Polypropylene is dissolved in a halogenated hydrocarbon spinning liquid, and a spinning liquid containing polyethylene at 10-20% by weight of the solution is prepared at a temperature in the range of 130-210°C and 15% by weight of the solution.
During the flash spinning of plexifilamentary film-fibril yarns produced at pressures above 0.00 psi and flash spinning this solution to a region of substantially lower temperatures and pressures, halogenated hydrocarbons are
-dichloro-2,2,2-trifluoroethane, 1,2
-dichloro-1,2,2-trifluoroethane, 1,1
- The flash method selected from the group consisting of dichloro-2,2-difluoroethane, 1,2-dichloro-1,1-difluoroethane and 1,1-dichloro-1-fluoroethane. 5. The fiber-forming polyolefin is added to a halogenated hydrocarbon spinning liquid at a temperature in the range of 130-210°C and 100°C.
The fiber-forming polyolefin is dissolved at a pressure of 0 psi or higher, provided that the spinning liquid contains a hydrocarbon co-solvent representing 2-25% of the total weight of the spinning liquid, so that the fiber-forming polyolefin is dissolved at 1% of the solution.
During the flash spinning of flexifilamentary film-fibril yarns, a spinning solution containing 0 to 20% by weight of halogenated hydrocarbons is produced, which is then flash spun into a region of substantially lower temperature and pressure. 1-dichloro-2,2,2-trifluoroethane, 1,2-dichloro-1,2,2-trifluoroethane, 1,1-dichloro-2,2-difluoroethane, 1,
2-dichloro-1,1-difluoroethane, and 1,1
- dichloro-1-fluoroethane. 6. The fiber-forming polyolefin is added to a halogenated hydrocarbon spinning liquid at a temperature in the range of 130-210°C and 100°C.
The fiber-forming polyolefin is dissolved at a pressure greater than 0 psi, provided that the spinning liquid contains methylene chloride representing 5 to 10% of the total weight of the spinning liquid, so that the fiber-forming polyolefin is
During the flash spinning of flexifilamentary film-fibril yarns, a spinning solution containing ~20% by weight is produced which is then flash spun into a region of substantially lower temperature and pressure. -dichloro-2,2,2-trifluoroethane,
1,2-dichloro-1,2,2-trifluoroethane,
1,1-dichloro-2,2-difluoroethane, 1,2
-dichloro-1,1-difluoroethane, and 1,1-
The flash spinning method selected from the group consisting of dichloro-1-fluoroethane. 7. 10 to 20% by weight of polyolefin forming fibers and 1,1-dichloro-2,2,2-trifluoroethane, 1,2-dichloro-1,2,2-trifluoroethane, 1,1-dichloro -2,2-difluoroethane, 1,
2-dichloro-1,1-difluoroethane, and 1,1
- A solution consisting essentially of 90-80% by weight of a liquid comprising a halogenated hydrocarbon selected from the group consisting of: - dichloro-1-fluoroethane. 8. 10 to 20% by weight of polyolefin forming fibers and 1,1-dichloro-2,2,2-trifluoroethane, 1,2-dichloro-1,2,2-trifluoroethane, 1,1-dichloro -2,2-difluoroethane, 1,
2-dichloro-1,1-difluoroethane, and 1,1
- A solution consisting essentially of 90 to 80% by weight of a halogenated hydrocarbon liquid selected from the group consisting of dichloro-1-fluoroethane.