JPH01272842A - Production of high-tenacity polyethylene multi-filament yarn - Google Patents

Abstract

PURPOSE:To obtain the subject yarn having remarkably improved utilization ratio of single fiber strength to the final multi-filament yarn and useful for various ropes, etc., by applying creep deformation to a polyethylene multi- filament yarn having high modulus and strength. CONSTITUTION:The objective yarn can be produced by using a polyethylene multi-filament yarn having high modulus and strength in a state of single yarn or doubled yarn and maintaining the yarn at a temperature to allow creep deformation of said filament and between room temperature and the melting point of polyethylene under a load corresponding to 10-60% of the breaking load under normal temperature, thereby effecting creep deformation of the yarn. Preferably, the creep deformation ratio is 5-25% and the filament is a multi-filament spun from an ultra-high-molecular weight polyethylene and having an elastic modulus of >=40GPa and a strength of >=1.5GPa.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a method for producing a high-strength polyethylene multifilament yarn, and more specifically, to a polyethylene multifilament yarn with significantly improved utilization of single fiber strength. Concerning the manufacturing method of strips.

(Prior Art) It is already known that a molecularly oriented molded article having high elastic modulus and high tensile modulus can be obtained by forming ultra-high molecular weight polyethylene into fibers, tapes, etc. and stretching the fibers, etc. JP-A-56-15408 describes spinning a dilute solution of ultra-high molecular weight polyethylene and drawing the resulting filament. Also, JP-A-59-
130313 describes that ultra-high molecular weight polyethylene and wax are melt-kneaded, the kneaded product is extruded, cooled and solidified, and then stretched.
Publication i14 describes that the above-mentioned melt-kneaded product is extruded, drafted, cooled and solidified, and then stretched.

These high-strength polyethylene fibers are widely used for industrial fiber applications such as various ropes, various nets, and industrial canvases by utilizing their characteristics such as high elastic modulus and high strength.

(Problems to be Solved by the Invention) Generally, when braiding lobes using multifilaments, if the elastic modulus varies among the constituent monofilaments, the monofilaments (j
There is a problem that the strength of the 111a fibers is not reflected in the lobe strength, that is, the problem is that the twist is reduced.

This problem is unacceptable for high-modulus fibers with low elongation, especially the aforementioned high-strength polyethylene IA fibers.
This is a major obstacle in the application of high modulus fibers.

Therefore, an object of the present invention is to provide a polyethylene multifilament yarn in which each single fiber in a high-strength polyethylene multifilament yarn has uniform elastic modulus and strength, and as a result, the utilization rate of the single fiber strength is significantly improved. The present invention provides a method for manufacturing a strip.

(Means for Solving the Problems) According to the present invention, a high elastic modulus/high strength polyethylene multifilament yarn, in the state of a single yarn or a gold thread, is heated to a temperature higher than room temperature, lower than the melting point of polyethylene, and Provided is a method for producing a high-strength polyethylene multifilament thread, which is characterized by creep deformation by stretching the filament under a load of 10 to 60% of the breaking load at room temperature at a temperature where creep deformation of the filament may occur. .

(Function) One of the drawbacks of high modulus and high strength polyethylene fibers is creep property. The present inventor conducted a detailed analysis of the creep properties of the above-mentioned fibers and found the following interesting facts. That is, 10 to 60% of the breaking load for high modulus and high strength polyethylene fibers.
, particularly preferably by applying a load of 20 to 50% for a long period of time (
(Creep is accelerated and shortened at high temperatures.) In creeped samples, the elastic modulus increases temporarily as the creep elongation increases (probably due to tension in the amorphous region), but then the creep elongation increases. It was found that there is a region where the elastic modulus and strength are kept constant.

To explain this point in detail, Figure 1 of the attached drawings shows the following:
This is an explanatory diagram showing the relationship between load application time and elongation, where the initial elongation is small (usually 0.5 to 0.7%).
There is a region of elongation followed by a region of creep elongation. Figure 2 is a diagram showing the relationship between creep elongation (including initial elongation, the same applies hereinafter) and strength retention in high-modulus, high-strength polyethylene fibers, and Figure 3 is a diagram showing the relationship between creep elongation and elastic modulus retention in high-modulus, high-strength polyethylene fibers. FIG.

These results reveal the fact that the tensile properties of high-modulus, high-strength polyethylene fibers do not depend on creep elongation after creep elongation. This phenomenon is unique to high-modulus, high-strength polyethylene fibers, and aramid fibers, which are a typical example of high-modulus fibers, suffer from a decrease in strength when allowed to creep. The reason why there is a region of elongation where the elastic modulus and strength are constant with respect to creep elongation is thought to be because crystal wall solution occurs in this region of elongation.

In the present invention, by giving a predetermined creep deformation to a high elastic modulus and high strength polyethylene multifilament yarn,
The uneven elastic modulus and strength of individual single fibers caused by uneven stretching during fiber preparation are evened out, and the utilization rate of single fiber strength in the multifilament yarn body is significantly improved.

(Preferred embodiment of the invention) The raw material multifilament yarn high elastic modulus/high strength polyethylene multifilament has a tensile elastic modulus of 400 Pa or more as a single fiber,
In particular, those having a tensile strength of 60 GPa or more and a tensile strength of 1.5 GPa or more, especially 2.0 GPa or more are used.

Such multifilaments can be obtained by spinning a composition containing ultra-high molecular weight polyethylene and a diluent into a multifilament, and then drawing the multifilament. The ultra-high molecular weight polyethylene is one having an intrinsic viscosity [η] of decalin solvent at 135° C. of 5 dl/g or more, preferably in the range of 7 to 3 odg/g. [η] is 5 d
If it is less than 1/g, even if the stretching ratio is increased, a stretched product with excellent tensile strength cannot be obtained. Although there is no particular upper limit to [η], those exceeding 3 odt/g have extremely high melt viscosity at high concentrations, tend to cause melt fractures during extrusion, and have poor melt spinnability. Such ultra-high molecular weight polyethylene refers to ethylene or ethylene and small amounts of other α-olefins, such as propylene, 1
Among the polyethylenes obtained by polymerizing -butene, 4-methyl-1-pentene, 1-hexene, etc. by so-called Ziegler polymerization, it has a much higher molecular weight.

As the diluent, a solvent for ultra-high molecular weight polyethylene and various wax-like substances having compatibility with ultra-high molecular weight polyethylene are used.

The solvent preferably has a boiling point higher than the melting point of the polyethylene, more preferably higher than the melting point +20°C.

Specific examples of such solvents include n-nonane, n-decane, n-undecane, n-dodecane, n-tetradecane, n-octadecane, liquid paraffin, aliphatic hydrocarbon solvents such as kerosene, xylene, and naphthalene. , aromatic hydrocarbon solvents such as tetralin, butylbenzene, p-cymene, cyclohexylbenzene, diethylbenzene, pentylbenzene, dodecylbenzene, bicyclohexyl, decalin, methylnaphthalene, ethylnaphthalene or their hydrogenated derivatives, 1,1, 2゜Halogenated hydrocarbon solvents such as 2-tetrachloroethane, pentachloroethane, hexachloroethane, 1,2.3-)-dichloropropane, dichlorobenzene, 1,2.4-trichlorobenzene, bromobenzene, paraffinic process oil , naphthenic process oil, aromatic process oil and the like.

As the waxes, aliphatic hydrocarbon compounds or derivatives thereof are used.

The aliphatic hydrocarbon compounds are mainly saturated aliphatic hydrocarbon compounds, and usually have a molecular weight of 2000 or less,
It is preferably a so-called paraffin wax having a molecular weight of 1000 or less, more preferably 800 or less. These aliphatic hydrocarbon compounds include tocosan, tricosane, tetracosane, triacontane, etc. having 2 carbon atoms.
A mixture of two or more n-alkanes or a lower n-alkane containing these as main components, 1 minute from petroleum! So-called paraffin wax manufactured by Ili, medium/low pressure polyethylene wax which is a low molecular weight polymer obtained by copolymerizing ethylene or ethylene with other α-olefins, high pressure polyethylene wax, ethylene copolymer wax, or medium/low pressure Examples include waxes obtained by reducing the molecular weight of polyethylene such as processed polyethylene and high-pressure processed polyethylene by thermal degradation, oxides of these waxes, oxidized waxes modified with maleic acid, and waxes modified with maleic acid.

Examples of the aliphatic hydrocarbon compound conductor include one or more carboxyl groups, preferably one to two carboxyl groups, particularly preferably one carboxyl group, at the end or inside of an aliphatic hydrocarbon group (alkyl group, alkenyl group), It is a compound having a functional group such as a hydroxyl group, a carbamoyl group, an ester group, a mercapto group, or a carbonyl group, and has a carbon number of 8 or more, preferably a carbon number of 12 to 50, or a molecular weight of 130 to 2,000. Preferably, 200 to 800 fatty acids, aliphatic alcohols, fatty acid amides, fatty acid esters, aliphatic mercaptans, aliphatic aldehydes, aliphatic ketones, etc. can be mentioned.

Specifically, the fatty acids include capric acid, lauric acid, myristic acid, balmitic acid, stearic acid, and oleic acid; the aliphatic alcohols include lauryl alcohol, myristyl alcohol, cetyl alcohol, and stearyl alcohol; and the aliphatic amides include caprinamide and laurinamide. , valmitinamide, stearylamide, and stearyl acetate as the fatty acid ester.

The diluent is preferably used in an amount of 33 to 9,900 parts by weight, particularly 100 to 1,900 parts by weight per 100 parts by weight of ultra-high molecular weight polyethylene, although it varies depending on the type of diluent.

Melt kneading is generally preferably carried out at a temperature of 150 to 300°C, particularly 170 to 20°C; at temperatures lower than the above range, the melt viscosity becomes too high and melt molding becomes difficult; If it is high, the molecular weight of the ultra-high molecular weight polyethylene decreases due to thermal degradation, making it difficult to obtain a molded article with a high elastic modulus and high strength. The blending may be carried out by dry blending using a Henschel mixer, V-type blender, etc., or by melt mixing using an axle or multi-screw extruder.

A drawn multifilament is obtained by melt extruding this molten mixture through a spinneret. In this case, the molten material extruded from the spinneret may be subjected to drafting, that is, drawing in the molten state. Molten resin die
The ratio between the extrusion speed v0 in the orifice and the winding speed (2) of the undrawn material cooled and solidified can be defined as a draft ratio by the following equation.

Draft ratio = v/v0 (1) The draft ratio depends on the temperature of the mixture, the molecular weight of the ultra-high molecular weight polyethylene, etc., but is usually 3 or more, preferably 6 or more.

Multifilament drawing is generally carried out at 40 to 160°C.
It is particularly desirable to carry out the process at a temperature of 80 to 145°C. As a heat medium for heating and maintaining the undrawn filament at the above temperature, any of air, water vapor, and a liquid medium can be used. However, as a heating medium, a solvent capable of eluting and removing the diluent mentioned above and whose boiling point is higher than the melting point of the molded article composition, specifically decalin, decane, kerosene, etc., is used to stretch the material. This operation is preferable because it becomes possible to remove the diluent described above, eliminate stretching unevenness during stretching, and achieve a high stretching ratio.

Of course, the means for removing excess diluent from ultra-high molecular weight polyethylene is not limited to the above-mentioned method, but also a method of treating an undrawn filament with a solvent such as hexane, heptane, hot ethanol, chloroform, benzene, etc., and then drawing the drawn product. Treatment with a solvent such as hexane, heptane, hot ethanol, chloroform, benzene, etc. can also effectively remove excess diluent from the filament and provide a drawn filament with high elastic modulus and high strength.

The stretching operation can be performed in one stage or in multiple stages of two or more stages. Although the stretching ratio depends on the desired molecular orientation effect, satisfactory results can be obtained if the stretching operation is performed at a stretching ratio of generally 5 to 80 times, particularly 10 to 50 times. Note that the multifilament is easily drawn between rollers having different circumferential speeds.

The fineness of single fibers in high elastic modulus/high strength polyethylene multifilament yarn is not particularly limited, but is generally 0.
．． It is preferably in the range of 5 to 20 deniers, especially 1.0 to 15 deniers.

The degree of molecular orientation in the filament can be determined by X-ray diffraction method,
In the case of the polyethylene multifilament used in the present invention, which can be determined by birefringence method, fluorescence polarization method, etc., it is described in detail in, for example, Yukichi Go, Teruichi Kubo: Industrial Chemistry Magazine Vol. 39, p. 992 (1939). The degree of orientation according to the half-width, that is, the half-width of the intensity distribution curve along the Debye ring of the strongest paratropic surface on the equator.

The degree of orientation (F) defined by is 0.90 or more, especially 0.9
It is preferable that the molecules are oriented so that the number of molecules is 5 or more.

The high elastic modulus and high strength polyethylene multifilament yarn used in the present invention can be obtained by the above method, and this
It can also be produced manually by Allied under the trade name Spectra, or by Mitsui Petrochemical Industries ■ under the trade name Tecmilon.

According to the present invention, high elastic modulus and high strength polyethylene multifilament yarn is subjected to creep deformation treatment in the form of a single yarn or after being compounded to obtain the necessary fineness. .

This creep deformation treatment is performed at a temperature higher than room temperature, lower than the melting point of polyethylene, and at which creep deformation can occur. Generally, the treatment temperature is preferably in the range of 40 to 80°C, particularly 50 to 75°C. If the treatment temperature is lower than the above range, the creep deformation treatment will take a long time, which is unfavorable from the viewpoint of productivity, while if it is higher than the above range, it is unfavorable because of orientation relaxation. In order to maintain the multifilament yarn to be treated at the above temperature, any of a heated air bath, a steam bath, a liquid medium bath, etc. can be used.

The load applied to the multifilament yarn is 10 to 60%, particularly 20%, of the room temperature breaking load of the multifilament yarn.
Loads in the range of 50% to 50% are suitable. If this creep load is smaller than the above range, it will be sufficient to make the elastic modulus and strength of each single fiber uniform, and there will be no tendency for leap deformation to occur.On the other hand, if it is larger than the above range, the Problems such as breakage are more likely to occur. In order to apply the above-mentioned load to the multifilament yarn, any known tensioning device such as a tension roller, a tenter, etc. can be used, and this tensioning can be carried out either continuously or batchwise. obtain. This tensioning process involves maintaining the multifilament yarn at the above-mentioned temperature, and applying a certain tension (load) within the above-mentioned range to supporting members such as rollers and frames that support the multifilament yarn.
This can be done by allowing creep elongation in the multifilament yarn.

During this treatment, the time required to cause creep deformation varies depending on the treatment temperature and load, and cannot be unconditionally specified, but it is necessary to
Any material that can achieve a creep elongation of 7 to 25%, especially a creep elongation of 7 to 20% is fine. Usually 10.
A creep deformation treatment of 0 to 10,000 seconds, especially 200 to 1,000 seconds is preferred.

In the case of lobes, the creep deformation treatment of the present invention is generally preferably performed on multifilament yarns before being braided into lobes, but it is of course possible to perform the creep deformation treatment on lobes after braiding multifilament yarns.

After the creep deformation treatment, the multifilament yarn is dimensionally stable because even if the load is removed and the initial elongation shrinks, the creep elongation does not return to its original state.

(Example) The invention will be specifically explained with the following example.

Example 1 and Comparative Example 1 A polyethylene multifilament yarn having the following properties and manufactured by the method described in the main text of the specification was used as the high elastic modulus/high strength polyethylene multifilament yarn.

Intrinsic viscosity: 8.5 di! , 7g Tensile modulus: 80 GPa (944g/Denny J bow 1 Bow length strength: 2.5 GPa
(29.5g/denier) Elongation: 4.1
Zero multifilament fineness: 10 denier x 100 pieces - 1
An 8-stroke braided lobe was manufactured using two twisted yarns of 000 denier twisted 30 times per meter (1000 denier x 2 x 2 x 8).

This lobe has an outer diameter of 6.0 1 m and a weight per length of 4.47 g 7 m, which is converted to a denier of 40.
It was equivalent to 23Q denier. The tensile properties of this lobe are shown in Table 1 (Comparative Example 1).

The above multifilament yarn was heated to 70℃ (in a hot water bath).
A load of about 30% of the breaking load was applied to produce about 10% creep elongation. The elongation rate is 2% strain/min, which is approximately equal to the elongation rate under its own weight.

A braided lobe was manufactured in the same manner as above except for using this creep-treated multifilament yarn. This lobe has an outer diameter of 5.8 mm and a weight per length of 4.06 g.
/m, and when converted to denier, it was 36.570 denier. The tensile properties of this lobe are shown in Table 1 (Example 1).

Table 1 In addition, the utilization rate in Table 1 was calculated from the following formula.

Here, the denominator represents the strength when 100% of the strength of the multifilament constituting the lobe is exerted.

(Effects of the Invention) According to the present invention, by causing creep deformation to a high elastic modulus, high strength polyethylene multifilament yarn, the elastic modulus and strength of individual single fibers can be made uniform. IL to the final multifilament striatum
The utilization rate of fiber strength was significantly improved, thereby reducing twist loss.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the relationship between load application time and elongation of high modulus, high strength polyethylene fibers, and Figure 2 is a diagram showing the relationship between creep elongation and strength retention for the above fibers. , FIG. 3 is a diagram showing the relationship between creep elongation and elastic modulus retention for the above fibers. Patent applicant: Mitsui Petrochemical Industries, Ltd. Figure 1 Figure 2 Creep damage ('/, ) Figure 3

Claims (3)

[Claims] (1) A high elastic modulus/high strength polyethylene multifilament yarn, in the form of a single yarn or a double yarn, is stored at room temperature at a temperature higher than room temperature, lower than the melting point of polyethylene, and at which creep deformation of the polyethylene filament may occur. A method for producing a high-strength polyethylene multifilament thread, which is characterized by creep deformation by stretching it under a load of 10 to 60% of the breaking load. (2) The manufacturing method according to claim 1, wherein creep deformation is performed to produce a creep elongation of 5 to 25%. (3) The method according to claim 1, wherein the multifilament of high elastic modulus and high strength polyethylene is a multifilament spun from ultra-high molecular weight polyethylene and has an elastic modulus of 40 GPa or more and a strength of 1.5 GPa or more.