JPH01124617A - Melt spinning method - Google Patents

Abstract

PURPOSE: To provide a method for melt-spinning a thermoplastic polymer, enabling the production of thermoplastic polymer fibers having excellent tensile strength, bending modulus, or the like, by melt-spinning an alternating copolymer of a specific olefinic unsaturated compound and carbon monoxide at a specific temperature and then drawing the spun fibers. CONSTITUTION: This method for melt-spinning a thermoplastic polymer comprises melt-spinning an alternating copolymer of an olefinic unsaturated compound having a mol.wt. of >=2,000, preferably >=5,000, and carbon monoxide at a temperature of at least (T+20)K (T is a crystal melting point), preferably at least (T+40)K, and subsequently drawing the spun fibers at a temperature of at most (T-10)K, preferably at most (T-25)K, preferably at a drawing ratio of 3:1 or larger, to obtain the thermoplastic polymer fibers suitable for tire cords. The copolymer is excellent ethylene/CO copolymer.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing thermoplastic polymer fibers by melt spinning and to tires containing fibers so spun.

Melt-spun thermoplastic fibers can be used in the manufacture of vehicle tires, and today a significant tonnage of such fibers is consumed on the market. A large number of polymers utilized in this way are polyamides and polyesters, but
Polypropylene fibers can also be used. However, for each tire, a large amount of fiber must be used relative to the amount of elastomer, which is determined primarily by the balance of properties of the polymer, determined by a combination of tensile strength, flexural modulus, and adhesion to rubber. This is to take. From this point of view, it is not possible to reduce the amount of fiber per tire without at the expense of adversely affecting the quality of the tire, ie making the tire unsuitable for many applications in the market. Polyaramid (
Other thermoplastic fibers, such as those sold under the tradenames KIEVL8R or TW^I'lON) or gel-spun high molecular weight polyethylene, are more suitable in this regard, but are too expensive for use in tire manufacturing.

The inventors have discovered that another class of thermoplastic polymers, namely alternating copolymers of olefinically unsaturated hydrocarbons and -carbon oxides, holds great promise for solving the problem of reducing the relative weight of fibers used in tire manufacturing. I discovered that.

Compared to polyamide, polynisder or polypropylene, melt fibers of the above alternating copolymer types offer a combination of tensile strength, flexural modulus and adhesion to rubber, provided that melt spinning and drawing of the fibers is carried out under certain critical temperature conditions. The balance is excellent.

The present invention is a process for producing thermoplastic polymer fibers, comprising melt spinning alternating copolymers of -carbon oxides and olefinically unsaturated compounds having an average molecular weight of at least 2000 at a temperature of a minimum of (T+20) K; (T-
10) A method characterized by stretching at a temperature of K (where T is the crystalline melting point of the polymer).

Stretching is preferably carried out at a stretch ratio of at least 3:1, more preferably at least 7:1 and most preferably 15:1. Preferred stretching temperatures are at least 40 degrees below the crystalline melting point of the polymer, and preferred melt spinning temperatures are at least 40 degrees above the crystalline melting point of the polymer.

"Fiber" as used in Kimei RfAM includes mono- and multifilaments in addition to fibers. An "alternating" polymer is a copolymer in which CO units in the macromolecule alternate with units derived from olefins. Thus, in the macromolecular chain, each CO unit is placed next to one unit of the olefin, for example ethylene. The copolymer can be a true copolymer of carbon oxide and one specific olefin, preferably ethylene, or it can be a copolymer of carbon II and one or more olefins, such as ethylene and propylene. You can also. Suitable alternating copolymers, in which ethylene is preferably used as the main olefin in the case of
No. 21965, No. 213671 and No. 229408-
are known from U.S. Pat. No. 3,914,391 as well as methods for preparing them by catalytic copolymerization. 'JIM A suitable polymerization catalyst is one based on the palladium/phosphine system. The use of other known ethylene/CO copolymers produced using free radical catalysis without alternating structures is not contemplated by the present invention.

Typically, copolymers have molecules of 1,000 to 500,000
has.

Preferably the copolymer has an average molecular weight of at least 500
It should be 0, and preferably at least 8000. Particularly good results are obtained using copolymers with molecular weights of to, ooo to 50,000.

Some of the physical properties of "polyketone" polymers are:

It depends on the molecular weight of the remer and whether the polymer is a copolymer or terpolymer and, in the case of a terpolymer, the relative proportion of the second hydrocarbon present.

Typical melting points for such polymers are about 175-300
``C1 is most preferably 180 to 280°C.

Intrinsic viscosity (LV) of polymers effective for newly developed fibers
N) from 0.5 to 10 LVN, preferably from 8 to 10 LVN, determined by dissolving the polymer in meta-cresol of eo'c and using a standard capillary viscometer such as a Cannon-Ubbelol+de viscometer. 4 L
VN and fi are also preferably in the range of 0.8 to 2.5 LVN.

Melt spinning and drawing of fibers can be carried out using equipment currently available on the market.6 Fibers produced using the method of the present invention can be used with polymers made from polyamides, polyesters or polypropylene. In comparison, it has a significantly diffused ITS and IMfiT.

In this seedling, ITS represents the factor of improvement in bow length strength, ■8 represents the factor of improvement in modulus, and was compared using the same stretch ratio for the thermoplastic resin of the heel fiber brand. .

The same 1,'? measured using unstretched conventional compression molded specimens. Improvements in gender were recorded.

Particularly suitable thermoplastic polymers for use in the process of the invention are copolymers of ethylene and -carbon oxides, and especially copolymers of ethylene, propylene and -carbon in which the molar ratio of ethylene to propylene in the polymer chain is at least 3:1. It is a terpolymer of carbon oxide.

Suitable terpolymers have a molar ratio of ethylene to other unsaturated monomers in the polymer macromolecule of at least 3:1, preferably at least 8:1.
In addition to ethylene and carbon monoxide, butene, pentene, hexene, heptene, octene, nonene,
Decene, dodecene, styrene, methyl acrylate, methyl methacrylate, vinyl acetate, undecenoic acid,
Mention may be made of undecenol, 6-chlorohexene, terpolymers of N- and nyl-pyrrolidone and diethyl ester of vinyl-phosphonic acid.

The fibers of the invention are also very suitable for producing polymer mats. Such mats, especially non-woven (
spun-bot+nded non-woven) Pine 1'' can be used, for example, as a reinforcing layer in rolled roofing material membranes prepared from modified bitumen. Such roofing membranes are superior to known polyester reinforced roofing materials due to the high mechanical strength of the fibers and good adhesion to bitumen.

Other effective uses of the above-mentioned mats include so-called civil engineering textiles (heot), especially when woven into cloth or mesh.
There is production of ``extile''. This includes roads, drains,
1i'1 is a permeable synthetic membrane specially designed to be used as a construction material in the civil engineering field such as river banks, coastlines, embankments, etc. It is clear that civil engineering textiles made from the fibers of the present invention, which are also suitable for UV stabilization, have the desired tensile strength, E-modulus, water permeability and stain resistance. It is.

and 1.Currently commercially available fiber grade nylon-6 (N-6) and polypropylene (pp), -carbon oxide, ethylene, and
A comparative test was conducted by melt spinning an ethylene based alternating copolymer of 8 mole % propylene ethylene (CE) with a fiber grade. Polyamide has a molecular weight of 10.0
00-25,000, the polypropylene grade has a melt index of 20 dg/min, the copolymer has a molecular RI of 0,000-25,000 and a crystalline melting point of 493
It had K.

Nominal tensile strength and flexural modulus were measured using conventional compression molded specimens, and the fibers were melt spun and drawn at a 6:1 ratio. The drawing temperature of the alternating copolymer was 480K and the melt spinning temperature was 560K.

The test results are shown in the table below.

Adhesion of the fibers to the styrene-butadiene elas 1 hemer was determined by the dest method currently practiced in the tire manufacturing industry. The results are shown on a relative scale, where + means good, 10+ means very good, and 0+10 means far away.

The same batch of carbon monoxide, ethylene and propylene copolymer as used in Example 1 was heated to a temperature of 515-560°C.
Melt-spun through a porous spinneret at a temperature of 30°C to 0.5°C.
It was rapidly air cooled at 5"C and stretched 5 to 10 times. The multifilaments produced in this way were lightly twisted into threads, and two or three of them were combined to make a cord. These cords were woven. The fabric was then dipped in adhesive.

The fabric was stretched and annealed, thus resulting in a fabric cord exhibiting excellent adhesion, tensile strength and bending properties suitable for tire cord.

Claims (10)

[Claims] (1) A process for producing thermoplastic polymer fibers by melt spinning, in which alternating copolymers of olefinically unsaturated compounds and carbon monoxide having a molecular weight of at least 2000 are melted at a temperature of at least (T+20)K. Spinning and then drawing at a temperature of up to (T-10)K (with the exception of T
is the crystalline melting point of the polymer. (2) The method according to claim 1, wherein the melt spinning temperature is a minimum of (T+40)K. (3) The method according to claim 1 or 2, wherein the stretching temperature is a maximum of (T-25)K. (4) The method according to any one of claims 1 to 3, wherein the stretching ratio is at least 3:1. (5) The method according to claim 4, wherein the stretching ratio is at least 7:1. (6) The method according to any one of claims 1 to 5, wherein the molecular weight of the polymer is at least 5,000. (7) The method according to claim 6, wherein the molecular weight of the polymer is at least 8,000. (8) The method according to any one of claims 1 to 7, wherein the copolymer is an ethylene/CO copolymer. (9) the ethylene/propylene/C copolymer contains at most 25 mol% propylene relative to ethylene;
8. The method according to any one of claims 1 to 7, wherein the O terpolymer is an O terpolymer. (10) A fiber-containing tire produced by the method according to any one of claims 1 to 9.