JP5302739B2 - High strength polyhexamethylene adipamide fiber - Google Patents

Description

  The present invention relates to high strength polyhexamethylene adipamide fibers. In particular, the present invention relates to a high-strength polyhexamethylene adipamide fiber having high strength and excellent fatigue resistance when embedded in rubber and vulcanized as a rubber reinforcing fiber.

  Polyhexamethylene adipamide fibers are widely used as rubber reinforcing fibers for tire cords and the like because of their excellent toughness, adhesiveness, and fatigue resistance. Industrial material products are always required to be lightweight, and as a fiber reinforcing material, it is important to reduce the amount of fiber without impairing its function. In order to satisfy such a demand, it is required to develop a fiber having higher strength, and various studies have been made.

  As for high-strength polyhexamethylene adipamide fiber, for example, Japanese Patent No. 2559866 (hereinafter referred to as Patent Document 1) discloses that the relative viscosity of formic acid of polyhexamethylene adipamide forming the fiber is 85 or more. Disclosed is a process for producing a high fatigue-resistant, high-strength polyhexamethylene adipamide, characterized in that melt spinning is performed, the spun yarn is treated with a non-aqueous finish, and then multistage drawing is performed. Yes. However, as far as this example is concerned, the strength level of the fiber is in the range of 9.4 cN / dtex or less, and in the high strength level region of 9.5 cN / dtex or more of the present invention, it is described in the example. With the finishing compositions, the resorcinol-formaldehyde-latex (RFL) treated cord, the strength of the vulcanized cord, and the fatigue resistance were inadequate. In addition, the means for achieving high fatigue resistance is limited to a certain level of molecular weight and non-aqueous finishes. In the examples, the finishes are not diluted with mineral oil from the viewpoint of economy or environmental impact reduction. Although the crude oil is applied using oiling rolls as it is, the viscosity of the finishing agent crude oil is high, resulting in non-uniform adhesion of the finishing agent, and there are problems in process performance such as the actual number of cutting threads and fluff. there were.

In Japanese Patent No. 3291828 (refer to Patent Document 2 hereinafter), a strength of 9.7 cN / dtex or more with a specific fiber structure parameter satisfied and a specific treatment agent uniformly applied, and a cutting elongation of 16 are disclosed. % High strength nylon 66 fiber having a boiling water shrinkage of 4% or less is disclosed.
As a specific method for producing the high-strength nylon 66 fiber disclosed in Patent Document 2, the chip is immersed in a solution containing a copper compound, or adsorbed by applying the solution to the chip, and then sulfuric acid is used in solid phase polymerization. A high-polymerization degree polymer having a relative viscosity of 3.0 or more is melt-spun at a spinning temperature range of 280 ° C. to 310 ° C., and its characteristics are as follows:
(1) A heating cylinder of 10 to 100 cm is installed immediately below the spinneret, and the atmospheric temperature in the heating cylinder is set to 250 ° C. or higher.
(2) In the step of continuous hot drawing after cooling and solidification, before the take-up roll, the specific treatment agent component diluted with the higher hydrocarbon is applied at less than 50% of the total treatment agent to be applied.
(3) Next, a stretch of 1 to 10% is given between the take-up roll and the yarn supply roll to give a specific treating agent component diluted with crude oil or higher hydrocarbons.
(4) The specific treating agent is a treating agent component excellent in extreme pressure property, lubricity, and heat resistance, (A) 50 to 80% by weight of a divalent ester compound, and (B) carbon number C ₈ to C. Compound (B) composed of phosphoric acid sodium salt of ethylene oxide adduct of ₂₆ branched alcohols (n = 1-7), 0.3 to 10% by weight, polyhydric alcohol ethylene oxide adduct, mol of the adduct It is a processing agent containing 10 to 40% by weight of a compound (C) comprising a nonionic active agent obtained by reacting a compound having a number of 10 to 50 mol with mono- and dicarboxylic acids.
(5) Next, the stretching employs two or more stages of thermal stretching, the final stretching temperature is 230 ° C. or higher, and the film is wound after being relaxed by 8 to 12% between the relaxing rolls.

  Since the high-strength nylon 66 fiber produced by the production method disclosed in Patent Document 2 has a boiling water shrinkage of 4% or less, a nylon 66 polymer having a general polymerization degree (sulfuric acid relative viscosity of 3.6 or less). In high-strength polyamide fibers that use heat treatment, the heat shrinkage stress is small, so during the resorcinol-formaldehyde latex (RFL liquid) treatment, when heat treatment is performed for several tens of seconds in a heat treatment zone at around 230 ° C. with a constant tension, It is apparently hot drawn while promoting crystallization. The high-strength nylon 66 fiber overlaps that it is drawn at a draw ratio of 90% or more of the draw limit ratio, and structural defects increase during heat treatment during RFL treatment, and the toughness and fatigue resistance of the treated cord There was a problem that decreased. For this reason, as described in the example of Patent Document 2, it is necessary to prepare a nylon 66 polymer having a high degree of polymerization exceeding sulfuric acid relative viscosity 3.6 (120 formic acid relative viscosity) by solid phase polymerization. Since the melt viscosity becomes high at the same time as it becomes high, it is necessary to lower the melt viscosity of the nylon 66 polymer that forms a filament by attaching a 20 cm long heating tube as described in the above example, so that the running cost and equipment There was a problem of high cost.

  As for the finishing oil used in Patent Document 2, high-strength nylon 66 fiber to which a higher alcohol POEO adduct (treatment agent 3) having an emulsifying function to uniformly disperse the finishing oil in water is applied. Since refraction does not satisfy structural requirements, fatigue resistance is at a low level, and the specific treating agent component used from the description is limited to non-aqueous treating agents. For this reason, the finishing oil used in Patent Document 2 needs to be diluted with higher hydrocarbons and applied, and there is a problem that it is economically expensive and has a large environmental load. Furthermore, regarding the high-strength nylon 66 fiber described in Patent Document 2, since the final stretching temperature is 230 ° C. or higher, the surface of the stretching roll is severely soiled due to deterioration of the treatment agent, and fluff and yarn breakage occur. There was also a problem that the process performance was increased.

Japanese Patent No. 2559866 Japanese Patent No. 3291828

The problem to be solved by the present invention is to solve the above-mentioned problems in the prior art and to use a high-strength and high-fatigue-resistant high-strength polymer used in resorcinol-formaldehyde-latex (RFL liquid) treatment cords and vulcanization cords. It is to provide hexamethylene adipamide fiber.
The problem to be solved by the present invention is to combine polyhexamethylene adipamide (nylon 66) polymer more than necessary by suitably combining specific fiber properties and specific finishes applied to the fiber surface. Even if it is an emulsion finish (water dispersion) that is economical and environmentally friendly, it has high strength and high fatigue resistance when used as an RFL liquid treatment cord and vulcanization cord. In addition, high strength polyhexamethylene adipamide fiber having excellent process performance is also provided.

The present invention is as follows:
[1] A high-strength polyhexamethylene adipamide fiber comprising at least 95 mol% of hexamethylene adipamide units, the polyhexamethylene adipamide fiber having a relative formic acid relative viscosity of 60 or more and a strength of 9.5 cN / dtex or more, boiling water shrinkage ratio is 5.0% or more, cutting margin is 10% or more, and a finish is applied to the surface of the fiber by 0.5% per fiber weight. 2.5 are weight% granted, wherein the partition above agents are nonionic surfactants obtained by reacting a dicarboxylic acid and a monocarboxylic acid and an ethylene oxide adduct of a polyhydric alcohol, and a monocarboxylic acid multilingual It comprises a mixture of nonionic surfactants obtained by reacting ethylene oxide adducts of a polyhydric alcohol, and the dicarboxylic acid and monocarboxylic acid polyhydric alcohol ethylene oxa Nonionic surfactants obtained by the reaction with de adduct is contained in 5% to 25% by weight relative to the total the partition above ingredients, the high-strength polyhexamethylene adipamide fibers, characterized in that .

[2] The finishing agent is the following (a) to (c):
(A) The polyvalent ester compound is contained in an amount of 40 to 75% by weight based on the entire finishing agent component.
(B) POEO adduct of higher alcohol is contained at 10 to 45% by weight with respect to the whole finishing agent component,
(C) a nonionic activator obtained by reacting a dicarboxylic acid and a monocarboxylic acid with an ethylene oxide adduct of a polyhydric alcohol, and a nonion obtained by reacting a monocarboxylic acid with an ethylene oxide adduct of a polyhydric alcohol A mixture of activators is comprised between 15% and 50% by weight, based on the total finish component,
The high-strength polyhexamethylene adipamide fiber according to [1], which has the following characteristics:

  [3] The high-strength polyhexamethylene adipamide fiber according to [1] or [2], wherein the finishing agent is applied as an emulsion in which a finishing agent main component is dispersed in water.

Since the high-strength polyhexamethylene adipamide fiber of the present invention is a high-strength fiber having a strength of 9.5 cN / dtex or more, it can be applied to reduce the weight of materials used in various industries and has good fatigue resistance. In particular, it can be suitably used for weight reduction in rubber reinforcement applications such as tire cords.
In addition, the specific finish applied to the surface of the high-strength polyhexamethylene adipamide fiber of the present invention can be an emulsion (water dispersion) finish and is limited to conventional non-aqueous finishes. Compared with the conventional method for producing high-strength, high-fatigue-resistant polyhexamethylene adipamide fiber, it is effective for reducing economic impact and environmental burden, and is excellent in process stability.

FIG. 1 is a schematic view of a test spinning machine and a drawing machine used in Examples of the present invention.

  In the polyhexamethylene adipamide polymer used in the present invention, 95 mol% or more of the repeating unit of the molecular chain is hexamethylene adipamide, and may contain a copolymer component of less than 5 mol%. Examples of copolymer components include ε-caproamide, tetramethylene adipamide, hexamethylene sebacamide, hexamethylene sebacamide, hexamethylene sebacamide, hexamethylene isophthalamide, tetramethylene terephthalamide, xylene phthalate. Lamid etc. are mentioned. When the copolymerization component is contained in an amount of 5 mol% or more, the crystallinity of the polyhexamethylene adipamide fiber is lowered, and heat resistance and thermal dimensional stability are lowered, which is not preferable.

  In the present invention, the polyhexamethylene adipamide forming the fibers must be melt-spun so that the relative viscosity of formic acid is 60 or more. When the relative viscosity of formic acid is less than 60, the strength of 9.5 cN / dtex or more of the present invention cannot be stably obtained. The relative formic acid relative viscosity of the polyhexamethylene adipamide forming the fiber can be set by adjusting the relative formic acid relative viscosity, the water content, the polymer temperature during melt spinning, and the residence time of the raw material polymer to be used. The preferable range of the relative viscosity of formic acid of the polyhexamethylene adipamide forming the fiber is 60 to 120, and 65 to 110 is more preferable in view of the ease of melt spinning.

  The strength of the high strength polyhexamethylene adipamide fiber of the present invention is not less than 9.5 cN / dtex. When the strength is less than 9.5 cN / dtex, it does not contribute effectively to lightening materials for various industries, particularly weight reduction for rubber reinforcement such as tire cords. A preferable range of the strength of the high-strength polyhexamethylene adipamide fiber is 9.8 cN / dtex or more. On the other hand, the upper limit of the strength of the high strength polyhexamethylene adipamide fiber is 11.5 cN / dtex. When the strength exceeds 11.5 cN / dtex, fluff and yarn breakage increase and the number of steps is greatly reduced. The preferable upper limit of the strength of the high-strength polyhexamethylene adipamide fiber is 11 cN / dtex.

  Also, the boiling water shrinkage of the high-strength polyhexamethylene adipamide fiber of the present invention must be 5% or more. When the high-strength polyhexamethylene adipamide fiber of the present invention is treated with resorcin-formaldehyde-latex (RFL), it is heat-treated at a high temperature of 200 ° C. or higher under a constant tension for several tens of seconds. It will be stretched while promoting. For this reason, when the boiling water shrinkage rate is less than 5%, structural defects increase during the heat treatment during the RFL treatment, and the toughness of the treatment code decreases. When the boiling water shrinkage rate is 5% or more, the heat shrinkage stress becomes high, so that stretching during the resorcin-formaldehyde-latex (RFL) treatment is suppressed and a high-strength treatment cord can be obtained. A preferable range of the boiling water shrinkage is 5.5% to 12%.

Furthermore, the cutting margin of the high-strength polyhexamethylene adipamide fiber of the present invention is 10% or more. The cutting margin is defined by the following formula:
Cutting margin = [(A / B) -1] × 100%
{In the formula, A is formic acid relative viscosity of polyhexamethylene adipamide fiber after degreasing and drying, and B is formic acid relative viscosity of polyhexamethylene adipamide fiber after degreasing and drying. }.
The stretched and broken polyhexamethylene adipamide fiber refers to the polyhexamethylene adipamide fiber after being stretched and broken by a tensile tester.
When the cutting margin is less than 10%, not only the number of cutting yarns is increased and the process performance is lowered, but also the structural defect in the polyhexamethylene adipamide fiber is increased, and the fatigue resistance property that repeats the elongation and compression phenomenon is lowered. . A preferable range of the cutting margin of the high-strength polyhexamethylene adipamide fiber is 12% or more. On the other hand, the upper limit of the cutting margin is 50%. If the cutting margin exceeds 50%, the molecular chains are not sufficiently aligned in the fiber axis direction, and high-strength polyhexamethylene adipamide fibers of 9.5 cN / dtex or more cannot be obtained. A preferable range of the upper limit of the cutting margin is 45%.

The high-strength polyhexamethylene adipamide fiber of the present invention is produced by a direct spinning multi-stage drawing method and is stretched in contact with a drawing roll at a high tension. The finishing oil that reduces the frictional resistance between the single fibers forming the fiber needs to be evenly attached to the surface of the fiber in order to improve the strength of the vulcanized cord and improve fatigue resistance. .
Therefore, on the surface of the high-strength polyhexamethylene adipamide fiber according to the present invention, a nonionic activator obtained by reacting dicarboxylic acid and monocarboxylic acid with an ethylene oxide adduct of polyhydric alcohol, and monocarboxylic acid Contains a mixture of nonionic activators obtained by reacting with the polyhydric alcohol ethylene oxide adduct, and the dicarboxylic acid and monocarboxylic acid are obtained by reacting with the polyhydric alcohol ethylene oxide adduct. An active agent is applied at a rate of 0.5 to 2.5% by weight per fiber weight with a finish comprised of 5% to 25% by weight of the finish component .

Moreover, the finishing agent provided to the fiber surface is characterized by the following (a) to (c):
(A) A polyvalent ester compound is 40 to 75 weight% with respect to the whole finishing agent component.
(B) POEO adduct of higher alcohol is 10 to 45% by weight based on the whole finishing agent component.
(C) a nonionic activator obtained by reacting a dicarboxylic acid and a monocarboxylic acid with an ethylene oxide adduct of a polyhydric alcohol, and a nonion obtained by reacting a monocarboxylic acid with an ethylene oxide adduct of a polyhydric alcohol The mixture of activators is 15% to 50% by weight with respect to the total finish agent component.
When the amount of finish applied is less than 0.5%, the extreme pressure and the frictional resistance reduction effect (smoothness) between the metal surface and the high-strength polyhexamethylene adipamide fiber can be stably produced. It becomes difficult. On the other hand, when the adhesion amount of the finishing agent exceeds 2.5% by weight, the permeability of the RFL solution to the polyhexamethylene adipamide fiber is inhibited during the resorcin-formaldehyde-latex liquid (RFL liquid) treatment, and adhesion to rubber As a result, the intended fatigue resistance cannot be obtained. A preferable range of the coating amount of the finishing agent per fiber weight is 0.7 to 2.0% by weight.

  In the above finishing oil (also referred to as “finishing agent” throughout the present specification), as the polyvalent ester compound (a), as the divalent ester compound, 1,6-hexanediol, neopentyl glycol and the like Esters with monobasic acids such as oleic acid, erucic acid, isostearic acid, lauric acid, octylic acid, adipates such as dioleyl adipate, diisostearyl adipate, dioctyl adipate, di (2-octyldodecyl) adipate, sebatin Acid esters, dioleyl thiodipropionate, thiodipropionate such as dioctyl thiodipropionate, bisphenol A, ethylene oxide adducts of bisphenol A, esters of phenols with monobasic acids, trivalent or higher ester compounds As trimethylol group Bread, pentaerythritol, sorbitan, sorbitol, isocyanuric acid and oleic acid, erucic acid, isostearic acid, lauric acid, esters of monobasic acids such as octyl acid. From the viewpoint of heat resistance and smoothness, a mixture of a trivalent or higher valent ester compound and a divalent ester compound is preferred, and the trivalent or higher valent ester compound is 5 to 50% by weight, preferably 10 to 10%, based on the whole polyvalent ester compound. 40% by weight.

A polyvalent ester compound is 40 to 75 weight% with respect to the whole finishing agent main component. When the ratio of the polyhydric alcohol is less than 40%, the effect of reducing frictional resistance (smoothness) with the metal surface is impaired, and the process performance is greatly reduced. On the other hand, when it exceeds 75% by weight, the POEO adduct of higher alcohol (b), the nonionic activator obtained by reacting dicarboxylic acid and monocarboxylic acid with the ethylene oxide adduct of polyhydric alcohol, and monocarboxylic acid The amount of the nonionic active agent mixture (c) obtained by reacting with the polyhydric alcohol ethylene oxide adduct is relatively reduced, the emulsion stability is lowered, and the polyhexamethylene adipamide fiber is reduced. This will impair the effect of reducing the frictional resistance between the constituent single fibers, and the process performance and the strength and fatigue resistance of the vulcanized cord will be reduced. It is preferably 45 to 70% by weight.

The POEO adduct (b) of a higher alcohol is a linear or branched alcohol as the higher alcohol, and an alcohol having a carbon number of C _{8 to} C ₂₆ is preferable. Specifically, octyl alcohol, decyl alcohol, isodecyl alcohol, isodecyl alcohol, lauryl alcohol, isolauryl alcohol, oleyl alcohol, stearyl alcohol, isostearyl alcohol, 2-ethylhexyl alcohol, 2-heptylundecanol, etc. . A propylene oxide or ethylene oxide (POEO) adduct having a mole number of 10 to 50 mol is added to the polyhydric alcohol.

The POEO adduct of higher alcohol is 10 to 45% by weight with respect to the entire main component of the finishing agent. If the POEO adduct of higher alcohol is less than 10% by weight, a stable emulsion cannot be obtained, and thread breakage and fluff increase, resulting in a significant decrease in process performance. On the other hand, if it exceeds 45% by weight, the polyhydric alcohol compound (a), a nonionic activator obtained by reacting dicarboxylic acid and monocarboxylic acid with an ethylene oxide adduct of polyhydric alcohol, and monocarboxylic acid of polyhydric alcohol The amount of the nonionic active agent mixture (c) obtained by reacting with the ethylene oxide adduct is relatively reduced, and smoothness and the effect of reducing frictional resistance between the single fibers constituting the polyhexamethylene adipamide fiber As a result, the process performance, the strength of the vulcanized cord, and the fatigue resistance are reduced. It is preferably 15 to 40% by weight.

A nonionic activator obtained by reacting with a monocarboxylic acid and a dicarboxylic acid is obtained by reacting, as a polyhydric alcohol, a compound in which the number of moles of the ethylene oxide adduct is 10 to 50 moles with mono and dicarboxylic acids. Examples of the nonionic activator and polyhydric alcohol ethylene oxide adduct include hydrogenated castor oil ethylene oxide adduct, trimethylolpropane ethylene oxide adduct, and sorbitol ethylene oxide adduct, particularly hydrogenated castor oil ethylene oxide adduct. Things are preferred.
The monocarboxylic acid used in the nonionic active agent obtained by reacting with the monocarboxylic acid is stearic acid, oleic acid, isostearic acid, lauric acid, etc., but stearic acid and isostearic acid are particularly preferred.
The dicarboxylic acid used in the nonionic activator obtained by reacting with the dicarboxylic acid is maleic acid, adipic acid, sebacic acid, dodecanoic acid, etc., and maleic acid and adipic acid are particularly preferred.

Nonionic activator obtained by reacting dicarboxylic acid and monocarboxylic acid with ethylene oxide adduct of polyhydric alcohol, and nonionic activator obtained by reacting monocarboxylic acid with ethylene oxide adduct of polyhydric alcohol The mixture (c) is mixed and used so as to be 15 to 50% by weight with respect to the entire finishing agent main component. A nonionic active agent obtained by reacting a dicarboxylic acid and a monocarboxylic acid has high oil film strength, but is extremely unstable as an emulsion. On the other hand, the nonionic active agent obtained by reacting with a monocarboxylic acid has a relatively high emulsion stability, although the oil film strength is inferior to that of the nonionic active agent obtained by reacting a dicarboxylic acid and a monocarboxylic acid. By mixing and using, the emulsion stability of the nonionic active agent obtained by reacting the dicarboxylic acid and the monocarboxylic acid is synergistically improved.

Nonionic activator obtained by reacting dicarboxylic acid and monocarboxylic acid with ethylene oxide adduct of polyhydric alcohol, and nonionic activator obtained by reacting monocarboxylic acid with ethylene oxide adduct of polyhydric alcohol If the mixture (c) is less than 15% by weight relative to the total amount of the finishing agent component, the oil film strength is insufficient, a sufficient effect of reducing frictional resistance between single fibers cannot be obtained, and the target RFL liquid treatment cord strength Unable to obtain vulcanized cord strength and fatigue resistance. On the other hand, when it is 50% by weight or more, the oil film strength is sufficient, but the content of the polyester compound (a) and the POEO adduct (b) of higher alcohol is relatively decreased, and the smoothness and emulsification performance are decreased. However, process performance and emulsion stability are reduced. Nonionic activator obtained by reacting dicarboxylic acid and monocarboxylic acid with ethylene oxide adduct of polyhydric alcohol, and nonionic activator obtained by reacting monocarboxylic acid with ethylene oxide adduct of polyhydric alcohol A preferable range of the mixture is 20 to 45% by weight with respect to the entire finishing agent main component.

Further, the nonionic activator obtained by reacting the dicarboxylic acid and the monocarboxylic acid is contained in an amount of 5 to 25% by weight based on the entire finishing agent main component. When the nonionic activator obtained by reacting dicarboxylic acid and monocarboxylic acid is less than 5% by weight, sufficient oil film strength can be obtained even if a nonionic activator obtained by reacting with monocarboxylic acid is used in combination. I can't. If it exceeds 25% by weight, the nonionic active agent obtained by the reaction of the dicarboxylic acid and the monocarboxylic acid has a high viscosity, so that it remains on the drawing roll to promote soiling, or further reacts with the monocarboxylic acid. Even if the content of the nonionic active agent to be increased is increased, phase separation is likely to occur, and a stable emulsion cannot be obtained. A preferable range of the content of the nonionic activator obtained by reacting the dicarboxylic acid and the monocarboxylic acid is 10 to 22% by weight.

In addition to the above-mentioned finishing agent components (a), (b), and (c), a soap component for stabilizing the emulsion state of 3% by weight or less of an antioxidant or a finishing agent component dispersed in water. May be contained in an amount of 2% by weight or less.
Surprisingly and unexpectedly, by selecting a finishing agent to be applied to the surface of the high-strength polyhexamethylene adipamide fiber having the fiber properties specified in the present invention, the finishing agent is made into an emulsion (the main finishing agent). Even when the components are applied in a state of being dispersed in water, a vulcanized cord having high strength and high fatigue resistance can be obtained.

Next, the manufacturing method of the high strength polyhexamethylene adipamide fiber of this invention is demonstrated, referring FIG.
First, a prepolymer having a relative viscosity of 40 to 50 containing a stabilizer such as copper acetate, copper iodide, and alkali metal halide is produced by a known melt polymerization method to obtain polymer pellets. Next, the polymer pellets are polymerized to a formic acid relative viscosity of 80 to 120 by a known solid phase polymerization method. In addition, if it is a high molecular weight about 80-100 formic acid relative viscosity, it can obtain cheaply by adjusting a vacuum degree in the last step of a well-known melt polymerization method.

After the polyhexamethylene adipamide polymer is melted at a spinning temperature range of 280 ° C. to 310 ° C., the polymer is passed through a spinning pack incorporating a metal nonwoven fabric filter having pores of about 10 to 80 μm, and spun through the mouthpiece pores. Put out. A heating zone is provided directly below the base.
The yarn that has passed through the heating zone is rapidly cooled and solidified immediately below the heating zone, and then a finish is applied. The finishing agent is composed of the above-described finishing agent components, and may be provided with a non-aqueous finishing agent diluted with mineral oil. Preferably, an emulsion finishing oil having a finishing agent concentration of 15 to 35% by weight uses an oiling roll. Is granted. The amount of the finishing agent attached to the fiber is 0.5 to 2.5% by weight, preferably 0.7 to 2.0% by weight, based on the wound fiber.

  Next, for the stretching, multistage thermal stretching of two or more stages is employed using the apparatus illustrated in FIG. The overall draw ratio is 4.0 to 6.8 times, and usually 4.5 to 6.5 times. The stretching roll is composed of three or more pairs of stretching rolls, and 40% to 65% of the total stretching ratio is stretched between the first stretching roll and the second stretching roll, and finally between the second stretching roll and the third stretching roll. Stretched to the draw ratio. Since stretching between the second stretching roll and the third stretching roll requires a slow stretching strain rate, the second stretching roll has a surface roughness of the roll so that the yarn slips on the second stretching roll. Surface processing is performed so that the degree is Ra 2.5 to 5.5 μm. If the surface roughness of the second stretching roll is less than Ra 2.5 μm, it is difficult to sufficiently slow the stretching strain rate, and a high-strength polyhexamethylene adipa having high fatigue resistance with a cutting margin of 10% or more. It becomes difficult to obtain a mid fiber stably. On the other hand, if Ra exceeds 5.5 μm, the variation of the stretching strain rate becomes large and the stretching becomes unstable. A preferable range of the surface roughness of the second stretching roll is Ra 3.0 to 5.0 μm. In addition, you may extend | stretch between a 3rd extending | stretching roll and a 4th extending | stretching roll by making the 3rd extending | stretching roll surface roughness into the same range as a 2nd extending | stretching roll surface roughness.

  The stretched yarn is heat-set on the third stretching roll at 225 ° C. or lower, and then relaxed between the fourth stretching rolls and then wound. When the temperature of the third drawing roll exceeds 225 ° C., a high-strength polyhexamethylene adipamide fiber having a boiling water shrinkage of 5% or more cannot be obtained. A preferable range of the third stretching roll temperature is 220 ° C. or less. In addition, when extending | stretching between a 3rd extending | stretching roll and a 4th extending | stretching roll, or when winding directly after a 3rd extending | stretching roll, it winds up directly, relaxing after heat-setting on the final extending roll at the temperature of 225 degrees C or less. May be.

Next, the present invention will be described specifically by way of examples. In addition, this invention is not limited to a present Example.
First, a processing method and an evaluation method for each characteristic in the embodiment will be described.
Fineness, strength, elongation fineness, strength, and elongation were measured in accordance with JIS L 1017 8.3 and 8.5.

Boiling water shrinkage The boiling water shrinkage was measured according to JIS L 1017 8.14.

Finishing agent adhesion rate The finishing agent adhesion rate was measured according to JIS L 1017 8.16.

Formic acid relative viscosity Formic acid relative viscosity is the relative viscosity at 25 ° C. of a solution in which 90% formic acid is dissolved so that the polymer concentration is 8.4% by weight. The sample is a degreasing sample of polyhexamethylene adipamide fiber, and the finishing agent adhering to the fiber surface is degreased by repeating the operation of immersing the polyhexamethylene adipamide fiber in dichloromethane and shaking it three times. After that, the sample was sufficiently washed with water and adjusted to a water content of 1000 ppm or less with a 85 ° C. vacuum dryer.

Surface Roughness of Stretching Roll The surface roughness of the stretching roll was measured using a surface roughness measuring device (Surfcoder SE-40D-106 manufactured by Kosaka Co., Ltd.) and the stylus type surface roughness specified in JIS-B0601. . The measurement was repeated 50 times to obtain an arithmetic average value.

Using a resorcinol-formaldehyde-latex (RFL) liquid-treated cord high-strength ring twisting machine, 1400 dtex high-strength polyhexamethylene adipamide fiber was subjected to 39 twists / 10 cm twist (Z twist), then bottom twist 2 Each piece was twisted 39 times / 10 cm (S twist) to produce a raw cord. Next, the raw cord was treated with a resorcin-formaldehyde-latex (RFL) solution using a three-oven hot stretch apparatus (computetor). Hot stretch conditions (treatment temperature / tension) during the RFL treatment were the first zone: 160 ° C./1.4 kg, the second zone: 227 contact / 2.8 kg, and the third zone: 227 ° C./1.65 kg. . The strength and elongation of the obtained treated cord were measured according to JIS L 1017 8.5.

Vulcanization cord A strong RFL liquid treatment cord was buried in rubber and vulcanized for 40 minutes under free shrinkage with a heat press set at 155 ° C., then the vulcanization cord was taken out and in accordance with JIS L 1017 8.5. The strength of the vulcanization cord was measured.

Goodyear tube fatigue test and post-fatigue vulcanization cord strength According to JIS L 1017 3.2.2.1A, vulcanization conditions 140 ° C x 40 minutes, tube shape (inner diameter: 12.5 mm, outer diameter: 26 mm, length : 230 mm), and a tube was processed for 700 minutes at a bending angle of 90 °, an internal pressure of 3.5 kg / cm ² , and a rotational speed of 850 rpm.
The treated tube was disassembled, the vulcanized cord was taken out, and the vulcanized cord strength after the fatigue test was measured in accordance with JIS L 1017 8.5.

Method for preparing stretched and fractured polyhexamethylene adipamide fiber sample Using autograph, after stretching until polyhexamethylene adipamide fiber is cut under the conditions of yarn length 25cm and tensile speed 300mm / min, chuck In between samples were taken.

Production method in this example A polyhexamethylene adipamide polymer having a relative viscosity of formic acid of 82 was obtained by applying a vacuum state at the final stage of the known melt polymerization method and melt polymerization. This polyhexamethylene adipamide polymer contained copper iodide corresponding to 70 ppm in terms of copper compound and potassium iodide corresponding to 1,800 ppm in terms of iodine content.
The polymer was introduced into a melt spinning machine and a drawing machine illustrated in FIG. 1 in a molten state to obtain a high strength polyhexamethylene adipamide fiber of 1440 dtex / 210f. Specifically, it is passed through a spinning pack (2) incorporating a metal nonwoven fabric filter having 60 μm pores incorporated in a spin head (1) set at 300 ° C., and spinning from a spinneret (2). I put it out. A heating zone (3) with a set temperature of 250 ° C and a length of 7 cm is provided directly below the base, and after passing through the heating atmosphere, cold air of 20 ° C is blown from the cooling air chamber (5) from the direction perpendicular to the yarn. It was cooled rapidly.

Next, a finishing agent is applied to the fiber with an oiling roll (6), taken up with a non-heated take-up roll (7), then led to a first drawing roll (8) with a roll temperature of 70 ° C., and then the surface roughness of the roll After stretching with a second stretching roll (9) having a roll temperature of 220 ° C. and a third stretching roll (10) with varying roll temperature, a fourth stretching roll (11) having a roll surface temperature of 150 ° C. After being relaxed, it was wound up by a winder (12). At this time, the number of cutting yarns when produced for 48 hours was evaluated, and the fiber properties of the obtained polyhexamethylene adipamide fiber were evaluated.
Next, a tube fatigue test was performed by performing RFL solution treatment and vulcanization treatment. At this time, the strength of the RFL-treated cord, the strength of the vulcanized cord, and the strength retention after the tube fatigue test (with respect to the strength of the RFL liquid-treated cord) were evaluated.

Example 1
The roughness of the second drawing roll is adjusted to Ra: 3.0 μm, the temperature of the third drawing roll is set to 220 ° C., and the finishing agent having the following composition of the finishing agent 1 is 1.1% by weight per weight of the fiber as an emulsion. Granted. Table 1 below shows the fiber properties of the obtained high-strength polyhexamethylene adipamide fiber, the number of cutting yarns, the strength of the RFL solution-treated cord, the strength of the vulcanized cord, and the strength retention after the tube fatigue test.

Finishing agent 1
(A) Trimethylolpropane trilaurate: 10 parts by weight
(A) Dioleylthiodipropionate: 40 parts by weight
(B) POEO stearyl polyether: 20 parts by weight
(C) Hardened castor oil EO ₂₅ maleic acid stearate: 15 parts by weight
Hardened castor oil EO ₂₅ triisostearate: 15 parts by weight The fiber properties of the obtained high-strength polyhexamethylene fiber are within the range specified in the claims, the number of cut yarns is small, and the treatment cord strength, vulcanization cord The strength retention after the strength and tube fatigue tests was also high.

Example 2
The roughness of the second drawing roll is adjusted to Ra: 4.5 μm, the temperature of the third drawing roll is set to 210 ° C., and the finishing agent having the following composition of the finishing agent 2 is 1.1% by weight per fiber weight in the emulsion. Granted. Table 1 below shows the fiber properties of the obtained high-strength polyhexamethylene adipamide fiber, the number of cutting yarns, the strength of the RFL solution-treated cord, the strength of the vulcanized cord, and the strength retention after the tube fatigue test.

Finishing agent 2
(A) Isocyanuric acid trioleate: 10 parts by weight
(A) Di (2-octyldodecyl) adipate: 40 parts by weight
(B) POEO 2-ethylhexyl polyether: 20 parts by weight
(C) Hardened castor oil EO ₂₅ adipic acid stearate: 13 parts by weight
Hardened castor oil EO ₂₅ triisostearate: 17 parts by weight The fiber properties of the obtained high-strength polyhexamethylene fiber are within the range specified in the claims, the cutting margin is 15% or more, and the boiling water shrinkage is It was 6% or more, the number of cut yarns was small, the processing cord strength, the vulcanization cord strength, and the strength retention after the tube fatigue test were at a high level.

Comparative Example 1
A high-strength polyhexamethylene adipamide fiber was obtained under the same conditions as in Example 1 except that the second drawing roll roughness was adjusted to Ra: 1.5 μm.
As shown in Table 1 below, the resulting polyhexamethylene adipamide fiber has a cutting margin of 6%, and the number of cutting yarns is larger than that in Example 1, and the treatment cord strength and vulcanization cord are increased. The strength retention after the strength and tube fatigue tests was also at a low level.

Comparative Example 2
A high-strength polyhexamethylene fiber was obtained under the same conditions as in Example 2 except that the third stretching roll temperature was set to 235 ° C.
As shown in Table 1 below, the boiling water shrinkage of the obtained polyhexamethylene adipamide fiber is as low as 3.5%, the treatment cord strength, the vulcanization cord strength, and the strength retention after the tube fatigue test are It was a low level.

Comparative Example 3
A high-strength polyhexamethylene adipamide fiber was obtained under the same conditions as in Example 1 except that 0.3% by weight of the emulsion finish was added per weight of the fiber.
As shown in Table 1 below, when the amount of the finishing agent attached decreases, smoothness and oil film strength are insufficient, so that the process performance is low, such as a large number of cutting yarns, and RFL treatment cord strength, vulcanization cord strength and The strength retention after the tube fatigue test also decreased.

Comparative Example 4
Polyhexamethylene adipamide fibers were obtained under the same conditions as in Example 1 except that 2.7% by weight of the emulsion finish was applied per fiber weight.
As shown in Table 1 below, when the amount of the finishing agent attached exceeds 2.5% by weight, the permeability of the RFL solution to the polyhexamethylene adipamide fiber is hindered and the adhesion to the rubber is greatly reduced. The strength retention after the fatigue test decreased.

Comparative Example 5
A high-strength polyhexamethylene adipamide fiber was obtained under the same conditions as in Example 1 except that the finishing agent 3 was added as an emulsion as the finishing agent component below.
Finishing agent 3
(A) Trimethylolpropane trilaurate: 10 parts by weight
(A) Dioleylthiodipropionate: 44 parts by weight
(B) POEO stearyl polyether: 20 parts by weight
(C) Hardened castor oil EO ₂₅ adipic acid stearate: 3 parts by weight
Hardened castor oil EO ₂₅ triisostearate: 23 parts by weight As shown in Table 1 below, the fiber properties of the obtained polyhexamethylene adipamide fiber are within the range specified in the claims, but dicarboxylic acid The content of the nonionic active agent obtained by the reaction of the carboxylic acid with the monocarboxylic acid is 5% by weight or less based on the total amount of the finishing agent component, and the treatment cord strength, the vulcanization cord strength, and the strength retention after the tube fatigue test are It was a low level.

Comparative Example 6
The conditions were the same as in Example 2 except that the finishing agent component was applied in the following finishing agent 4.
Finishing agent 4
(A) Isocyanuric acid trioleate: 10 parts by weight
(A) Di (2-octyldodecyl) adipate: 40 parts by weight
(B) POEO 2-ethylhexyl polyether: 12 parts by weight
(C) Hardened castor oil EO ₂₅ adipic acid stearate: 28 parts by weight
Hardened castor oil EO ₂₅ triisostearate: 10 parts by weight In finishing agent 4, a stable emulsion could not be obtained, and spinning of high-strength polyhexamethylene adipamide was impossible.

Comparative Example 7
The conditions were the same as in Example 1 except that the finishing agent component was applied in the following finishing agent 5.
Finishing agent 5
(A) Trimethylolpropane trilaurate: 10 parts by weight
(A) Dioleylthiodipropionate: 47 parts by weight
(B) POEO stearyl polyether: 25 parts by weight
(C) Hardened castor oil EO ₂₅ Adipic acid stearate: 18 parts by weight With finishing agent 5, a stable emulsion could not be obtained, and spinning of high-strength polyhexamethylene adipamide was impossible.

Reference Example 1 (Example 3)
As Reference Example 1, finishing agent 1 was diluted with _C18 hydrocarbon mineral oil, and high-strength polyhexamethylene adipamide fibers were obtained under the same conditions as in Example 1.
As shown in Table 1 below, even with a non-aqueous finishing oil diluted with an emulsion finishing agent or a hydrocarbon-based mineral oil, by adding a selected finishing agent with specific fiber properties, the number of cut yarns is also reduced. The processing strength, vulcanization strength, and strength retention after tube fatigue testing of the high strength polyhexamethylene adipamide fiber obtained were low and high.

Reference Example 2 (Comparative Example 8)
As Reference Example 2, the finishing agent 3 used in Comparative Example 5 was diluted with a _C18 hydrocarbon mineral oil to obtain high-strength polyhexamethylene adipamide fiber under the same conditions as in Example 1.
As shown in Table 1 below, even in the case of a non-aqueous finishing oil diluted with an emulsion finishing agent or a hydrocarbon-based mineral oil, the content of the nonionic active agent obtained by reacting a dicarboxylic acid and a monocarboxylic acid is In the case of 5% by weight or less based on the total amount of the finishing agent component, the treatment cord strength, vulcanization cord strength and strength retention after tube fatigue test of the obtained high strength polyhexamethylene adipamide fiber are low. It was.

  From the above examples, comparative examples, and reference examples, the fiber properties specified in the claims are satisfied and a specific finish is applied, so that even if the finish is an emulsion, the strength is 9.5 cN / dtex or more. High-strength polyhexamethylene adipamide fiber can be produced with good yield, and RFL liquid-treated cords and vulcanized cords using the high-strength polyhexamethylene adipamide fiber of the present invention have high strength and fatigue resistance Is found to be good.

  Since the high-strength polyhexamethylene adipamide fiber of the present invention is a high-strength fiber having a strength of 9.5 cN / dtex or more, it can be suitably used for reducing the weight of materials used in various industries, and also has fatigue resistance. Since it is good, it is particularly suitable for weight reduction of rubber reinforcement applications such as tire cords.

DESCRIPTION OF SYMBOLS 1 Spin head 2 Spin pack and spinneret 3 Heating zone 4 Filament 5 Cooling air chamber 6 Oiling roll 7 Take-up roll 8 1st extending roll 9 2nd extending roll 10 3rd extending roll 11 4th extending roll 12 Winding machine

Claims (3)

High-strength polyhexamethylene adipamide fiber comprising at least 95 mol% of hexamethylene adipamide units, wherein the polyhexamethylene adipamide fiber has a relative viscosity of formic acid of 60 or more and a strength of 9.5 cN / Dtex or more, the boiling water shrinkage is 5.0% or more, the cutting margin is 10% or more, and the finish is applied to the surface of the fiber by 0.5-2. 5 are weight percent granted, wherein the partition above agents are nonionic surfactants obtained by reacting a dicarboxylic acid and a monocarboxylic acid and an ethylene oxide adduct of a polyhydric alcohol, and a monocarboxylic acid of a polyhydric alcohol It comprises a mixture of nonionic surfactants obtained by reacting ethylene oxide adducts, and the dicarboxylic acid and the monocarboxylic acid with ethylene oxide of polyhydric alcohols Nonionic surfactants obtained by reacting with things, contains 5% to 25% by weight relative to the total the partition above ingredients, the high-strength polyhexamethylene adipamide fibers, characterized in that. The finishing agents are the following (a) to (c):
(A) The polyvalent ester compound is contained in an amount of 40 to 75% by weight based on the entire finishing agent component.
(B) POEO adduct of higher alcohol is contained at 10 to 45% by weight with respect to the whole finishing agent component,
(C) a nonionic activator obtained by reacting a dicarboxylic acid and a monocarboxylic acid with an ethylene oxide adduct of a polyhydric alcohol, and a nonion obtained by reacting a monocarboxylic acid with an ethylene oxide adduct of a polyhydric alcohol A mixture of activators is comprised between 15% and 50% by weight, based on the total finish component,
The high-strength polyhexamethylene adipamide fiber according to claim 1, which has the following characteristics. Said finishing agent, Ru is applied in an emulsion obtained by dispersing finish main component in water, high-strength polyhexamethylene adipamide fibers as claimed in claim 1 or 2.

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