JPH0949112A - High tenacity polyamide fiber and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently produce polyamide fibers suitable for various kinds of usages as industrial material, having high tenacity and excellent in strength retainability and fatigue resistance by using an aqueous emulsion oil agent. SOLUTION: The high tenacity polyamide fibers have a strength of >=10.0g/ denier, a breaking elongation of >=20% and a boiling water shrinkage of <10.0%. The fibers are obtained by subjecting undrawn polyamide fibers to hot drawing after applying an aqueous emulsion oil agent. The hot drawing is carried out immediately after the application of the aqueous emulsion so as to be <0.05sec of the time from the point of the application to the draw point generated by the hot drawing.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a polyamide fiber having high strength, excellent strength retention and fatigue resistance suitable for various industrial materials, and efficient production of this high strength polyamide fiber by using an aqueous emulsion oil agent. It is about how to do it.

[0002]

2. Description of the Related Art Polyamide fiber has excellent properties such as toughness, adhesiveness, and fatigue resistance, so that it has been conventionally used in various industrial materials such as tire cords, conveyor belts,
It is widely used in the fields of power transmission belts, rubber reinforcing cords such as rubber hoses, fishing nets, ropes, safety belts, slings, tarpaulins, tents, braids, and sewing threads.

When the polyamide fiber is used as a rubber-reinforcing cord, it has a strong holding property against thermal and mechanical stimuli, such as a twisting process, a heat setting process after applying an adhesive, and a rubber vulcanization process. Performances such as fatigue resistance against repeated fatigue during tire running have been strongly demanded of polyamide fibers, and many studies have been made so far to satisfy the required performances, for example, JP-A-54-54. 15022, JP-A-55-45
Japanese Patent Laid-Open No. 863 and Japanese Patent Laid-Open No. 1-168815 are proposed.

That is, the techniques described in JP-A-54-15022 and JP-A-55-45863 each use an aqueous emulsion oil agent as a spinning oil agent, and the aqueous emulsion oil agent is used for a polyamide unstretched yarn. Immediately after applying the fluid, a fluid is sprayed with an entanglement nozzle to uniformly migrate the oil agent to each filament of the unstretched yarn, and then hot stretching is performed. According to such a method, a high elongation of 10 g / d or more is achieved. It is disclosed that a polyamide fiber having high strength and excellent fatigue resistance can be obtained.

Further, in the technique disclosed in Japanese Patent Laid-Open No. 1-168815, immediately before the oil agent is applied to the polyamide undrawn yarn, it is passed through a steam atmosphere to uniformly steam the surface layer of each filament, and then the heat treatment is performed. It is a method of stretching, according to such a method, with a high strength of 10 g / d or more
Further, it is disclosed that the polyamide fiber having improved fatigue resistance and improved strength retention in the tire cord processing step can be obtained.

That is, in the above-mentioned conventional techniques, water is uniformly applied to the undrawn yarn of polyamide fiber by using an aqueous emulsion oil agent or steam.
It is disclosed that by heat drawing, a polyamide fiber having high strength and excellent strength retention and fatigue resistance can be obtained.

[0007] Thus, by giving water first and then hot drawing in the yarn making process, especially in the stage of undrawn yarn, polyamide fiber excellent in strength retention and fatigue resistance can be obtained. It is conventionally known that the polyamide fiber has a stable fiber structure corresponding to the development of the above-mentioned strength retention and fatigue resistance physical properties.

The term "stable fiber structure" as used herein means that the change in fiber structure is small when subjected to thermal or mechanical stimulus during the tire cord processing step or tire running.

However, the polyamide fiber produced by the above-mentioned prior art has the stable fiber structure formed by applying water at the stage of the undrawn yarn, and has excellent strength retention and fatigue resistance. However, there is a drawback that it is difficult to obtain high strength.

The reason why it becomes difficult to obtain a high-strength polyamide fiber by adding water to the polyamide unstretched yarn is considered to be as follows.

First, the water-permeated portion is more likely to crystallize during hot stretching than other portions, and the molecular chains are less likely to be oriented.
This is because the insufficiently oriented portion does not contribute to the strength. Therefore, the greater the degree of water penetration, the lower the degree of orientation of the entire fiber and the lower the strength.

Second, when water is applied to the undrawn yarn,
Since the water penetration between filaments and in the cross section of filaments varies, this causes variations in the fiber structure and physical properties between filaments, and even in this case sufficient molecular chain orientation cannot be achieved. However, high strength yarn cannot be obtained.

It is preferable that water permeates uniformly between the filaments and within the cross section of the filament, and also permeates from the surface of the filament to an appropriate depth, for example, a depth of 1 to 5 μm. You can tell by observing. In other words, it is possible to observe a portion where water has permeated as a surface crystal layer under a polarizing microscope.

Therefore, the polyamide fiber having high strength and excellent strength retention and fatigue resistance is provided with water evenly on the undrawn yarn so that the water is evenly permeated between the filaments and in the cross section of the filament, and It can be obtained by permeation to a depth of 5μ.

However, since the polyamide unstretched filaments melt-spun, spun from the spinneret, and solidified are in an absolutely dry state, when an aqueous emulsion oil agent is applied to them, water is instantly absorbed between the multifilaments and between the multifilaments. It is not possible to uniformly permeate water into the cross section of the filament.

As in the techniques disclosed in Japanese Patent Laid-Open Nos. 54-15022 and 55-45863,
In the method of migrating the oil agent between the filaments by immediately performing the entanglement treatment with the fluid after the application of the water-based emulsion oil agent, the water is relatively evenly applied between the filaments, and as a result, a high level up to about 9.6 g / d is achieved. Although the strength is obtained, the uniform penetration of water into the cross section of the filament is not controlled, resulting in 10 g.
It has been difficult to stably obtain high strength yarns of / d or more.

According to the method disclosed in Japanese Patent Laid-Open No. 1-168815, water is surely evenly permeated between filaments and inside the filament, and the depth of water permeation into the cross section of the fiber is also a steam treatment condition. Controllable, resulting in a high strength of 10 g / d or more, and a polyamide fiber with improved strength retention and fatigue resistance to some extent. The problem was the complexity of.

On the other hand, as a general process for stably producing a polyamide fiber having a high strength of 10 g / d or more, for example, JP-A-59-187617 and JP-A-58-115114 are known. As disclosed, there is a method in which a polyamide unstretched yarn is hot-stretched without applying water.

That is, according to the method of applying a non-aqueous oil agent and then hot-drawing, it is possible to easily obtain a polyamide fiber having high strength as compared with the method of applying an aqueous emulsion oil agent and then hot-drawing. .

However, the polyamide fiber obtained by using this non-aqueous oil agent is generally insufficient in terms of tenacity retention and fatigue resistance, and therefore, for example, in the spinning process and tire cord processing process, for example, hot drawing. Strengthening is maintained by combining improved means such as means for applying sufficient heat treatment afterwards, means for strengthening heat setting after adhesive application in the tire cord processing step, and means for selecting an appropriate oil agent or adhesive. It is necessary to improve the durability and fatigue resistance to a practically sufficient level, and the process is complicated in this respect, which is not an efficient method.

[0021]

SUMMARY OF THE INVENTION The present invention has been achieved as a result of studying how to solve the above-mentioned problems in the prior art.

Accordingly, an object of the present invention is to provide a polyamide fiber having high strength, excellent strength retention and fatigue resistance suitable for various industrial materials, and efficiently using this high strength polyamide fiber by using an aqueous emulsion oil agent. It is to provide a manufacturing method.

[0023]

In order to achieve the above object, the high strength polyamide fiber of the present invention has a strength of 10.
It is characterized by having 0 g / d or more, cutting elongation of 20% or more, and boiling water shrinkage of less than 10.0%.

The high-strength polyamide fiber having the above-mentioned characteristics is produced by applying a water-based emulsion oil agent to a polyamide unstretched yarn and then hot-drawing it to produce a high-strength polyamide fiber. It is manufactured by applying the aqueous emulsion oil agent and then immediately performing hot drawing so that the time from application to the draw point generated by the hot drawing is 0.05 seconds or less.

In the production of the high-strength polyamide fiber, it is also possible to apply an aqueous emulsion oil agent to the unstretched yarn and further apply a non-aqueous oil agent in the pre-stretch zone, and then immediately perform hot drawing.

Further, in the production of the above high-strength polyamide fibers, the above water-based emulsion oil agent is a hydrogenated castor oil in which the number of moles of ethylene oxide added is 25 moles or less and the number of carbon atoms in the alkyl chain of the adduct is 8 or more. It is preferable that the ethylene oxide adduct is contained as an activator in the oil agent component in an amount of 10% by weight or more, the thermal stretching is multi-stage stretching of two stages or more, and the stretching temperature is 210 ° C. or more. Is.

[0027]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.

The high-strength polyamide fiber of the present invention is characterized by a strength of 10.0 g / d or more, a breaking elongation of 20% or more, and a boiling water shrinkage ratio of less than 10.0%, which makes it suitable for various industries. It is suitable as a polyamide fiber for materials, and has characteristics of high strength and excellent strength retention and fatigue resistance.

Further, the high-strength polyamide fiber satisfying the above characteristics can be efficiently produced by an improved method using an aqueous emulsion oil agent.

That is, in the method for producing a high-strength polyamide fiber of the present invention, the water-based emulsion oil agent is applied to the polyamide unstretched yarn, and then immediately stretched, whereby dispersion of water adhesion between filaments of the polyamide unstretched yarn, It is characterized by minimizing the dispersion of penetration into the filament cross section, the obstacles in the spinning process caused by the longitudinal swelling of the polyamide unstretched yarn caused by the adsorption of water, and the accompanying deterioration of the properties of the polyamide fiber. To do.

Polyamides forming the high-strength polyamide fibers of the present invention include polycapramide, polyhexamethylene adipamide, polytetramethylene adipamide, etc., but these are 5% by weight or less of other copolymerization components. It may be a copolymer containing. Examples of the copolymerization component here include ε-caproamide, tetramethylene adipamide, hexamethylene sebacamide, hexamethylene isophthalamide, tetramethylene terephthalamide,
And xylylene phthalamide and the like.

When the content of the above-mentioned copolymerization component is 5 mol% or more, the crystallinity of the polyamide fiber is lowered, and the heat resistance and the thermal dimensional stability are lowered, which is not preferable.

The high-strength polyamide fiber according to the present invention preferably comprises a high-molecular-weight polyamide having a sulfuric acid relative viscosity of 3.0 or more, particularly 3.2 or more. If the relative viscosity of sulfuric acid of the polyamide is less than 3.0, the high strength and / or high toughness targeted by the present invention may not be stably obtained.

Further, since the high-strength polyamide fiber according to the present invention is preferably used for industrial materials such as rubber reinforcing materials and fishing nets, polyamide is used in order to impart heat resistance, weather resistance and oxidation resistance. Anti-aging agents are usually added.

As the antiaging agent, a copper compound and an organic or inorganic phosphorus compound, a halide of an alkali metal or an alkaline earth metal, a quaternary ammonium halide and a diphenylamine antioxidant, 2-mercaptobenzimidazole, and A hindered phenolic antioxidant or the like is used.

Specific examples of the copper compound include cupric acetate,
Cuprous iodide, cupric chloride, cuprous bromide, cupric bromide, copper phthalate, copper stearate, copper phosphate, copper pyrophosphate and complex salts of various copper salts with inorganic or organic compounds Is mentioned.

The amount of the antioxidant contained in the polyamide fiber is 30 to 150 ppm as copper in the case of a copper compound,
It is preferably 50 to 100 ppm. The addition amount of the antioxidant used together with the copper compound is preferably in the range of 0.01 to 0.5% by weight. .

In producing the high-strength polyamide fiber of the present invention, first, the above-mentioned polyamide polymer is added to a water content of 0.2.
% To less than 50% and then supplied to a spinning machine at a spinning temperature of 280
Melts in the range of ~ 310 ° C.

The molten polymer is then filtered in a spin pack through a non-woven metal filter having pores of about 5 to 50 μ, and then spun through the spinneret pores.

A heating cylinder having a length of 10 to 100 cm, preferably 15 to 50 cm is installed immediately below the mouthpiece, and the atmosphere temperature in the heating cylinder is 250 ° C. or higher, preferably 280 to 310 ° C.
And

The yarn gradually cooled by passing through the heating cylinder atmosphere is blown with cold air to be cooled and solidified.

Next, an aqueous emulsion oil agent is applied to the yarn, and the undrawn yarn applied with the oil agent is 300 to 1000 m / min, preferably 450 to 800 m by a take-up roll.
It is collected at a speed of / minute.

The take-up yarn is continuously sent to the drawing process and drawn without being once wound.

Although it is necessary to set the conditions of the heating cylinder and the take-up speed in relation to each other, the birefringence of the undrawn yarn is 2 × 10 ⁻³ to 15 × 10 ⁻³ , preferably 5 ×. 10
It is preferable that the condition is in the range of ⁻³ to 10 × 10 ⁻³ .

In the above, the conditions are set so that the time from the application of the water-based emulsion oil agent to the polyamide undrawn yarn and the time to the draw point occurrence point during hot drawing is 0.05 seconds or less, It is important to stretch immediately after applying the aqueous emulsion oil.

That is, since the polyamide undrawn yarn which is melted, spun from the spinneret pores, and cooled and solidified is in an absolutely dry state, when an aqueous emulsion oil agent is applied to this undrawn yarn, water is immediately adsorbed. .

Since the water is adsorbed quickly, it does not diffuse uniformly throughout the filaments, and it is adsorbed non-uniformly even within the cross section of each filament. If it is adsorbed non-uniformly, a non-uniform structure is formed between filaments and in the filament cross-section before being drawn, the yarn sways on the roll, and uniform drawing cannot be performed, resulting in a drawing yield. This leads to problems such as deterioration of the drawn yarn and deterioration of the physical properties of the drawn yarn.

Therefore, in order to improve the above obstacles, it is necessary to uniformly apply the water-based emulsion oil agent to the polyamide undrawn yarn thread and to evenly adsorb water in the cross section of each filament, and / Alternatively, when water cannot be adsorbed sufficiently uniformly, it is necessary to start drawing after the polyamide undrawn yarn has adsorbed water and before forming a non-uniform fiber structure.

Therefore, in the method for producing a high-strength polyamide fiber of the present invention, in the method of applying the aqueous emulsion oil agent to the polyamide unstretched yarn, and then stretching, at the time of applying the aqueous emulsion oil agent and by hot drawing. It is necessary to set the time to the draw point to occur to be 0.05 seconds or less, and apply the aqueous emulsion oil agent and then immediately perform hot stretching.

In order to carry out this method, after applying the water-based emulsion oil agent, it is necessary to immediately draw the yarn on the take-up roll without wrapping it around many times.

Therefore, the surface of the take-up roll is made a mirror surface having a large frictional force, and the polyamide undrawn yarn is circulated for less than one turn on a roll having a relatively long circumferential length, and then the yarn is immediately fed to the drawing zone.

The draw point generated in the stretching zone is a position of several cm to 50 cm from the exit of the take-up roll. Therefore, the distance from the application position of the water-based emulsion oil agent to the draw point is within about 150 cm, and the time required for the polyamide undrawn yarn to pass through both points varies depending on the spinning speed.
It is within 05 seconds, preferably within 0.04 seconds.

As another method, a non-aqueous oil agent is applied to a polyamide unstretched yarn and the yarn is taken up, and then the yarn is wound around a take-up roll, a pre-stretch roll, etc., as necessary, and further drawn. It is also possible to add the water-based emulsion oil agent or water most recently, and in this case,
The time from the position where the water-based emulsion oil agent or water is applied to the draw point may be set within 0.05 seconds.

In the present invention, the most preferable embodiment of the method for applying the water-based emulsion oil agent is as follows.

That is, the composition of the water-based emulsion oil agent applied to the polyamide undrawn yarn is preferably as follows.

The composition of the oil agent is designed so as to suppress the permeation of water into the polyamide unstretched yarn, and as a result, the filaments constituting the yarn are uniformly attached and even penetrated into the filament cross section. Easy to do.

The composition of the water-based emulsion oil agent is as follows: hydrogenated castor oil ethylene oxide adduct having an ethylene oxide addition mole number of 25 moles or less and carbon number in the alkyl chain of the adduct of 8 or more, specifically, The main component is rail adipate, and 10% by weight or more of P0E (20) hydrogenated castor oil trioleate is contained in the oil component as an active agent, and the mixing ratio of the active agent is 10% by weight.
The above is preferably 10 to 50% by weight.

After applying the above water-based emulsion oil,
An oil agent for the fiber-forming process of polyamide fiber and an oil agent for the higher-order processing step are applied or diluted with the crude oil agent. Usually, since the crude oil has a higher viscosity than the aqueous emulsion oil, it is applied while pre-stretching the yarn. The pre-stretch rate in this case is about 0.1 to 0.5%.

When the crude oil composition is mixed in the water-based emulsion oil agent, it is not necessary to apply the crude oil agent in the pre-stretching step. In order to design the composition of the water-based emulsion oil agent so as to suppress the permeation of water into the unstretched polyamide yarn, the water-based emulsion oil agent and the crude oil agent are selected because the oil agent composition and emulsion concentration have flexibility. The process of separating the application is preferred.

In the case of refueling in two stages, it is necessary to design the water-based emulsion oil agent so that gelation does not occur even when the water-based emulsion is mixed with the crude oil agent. It is a composition.

The concentration of the aqueous emulsion oil is usually 5 to 3
It is 0% by weight, preferably 10 to 25% by weight, and the amount of water applied to the polyamide undrawn yarn is 0.1 to 1.0% by weight, preferably 0.2 to 0.5% by weight.

As the hot stretching, a multi-stage hot stretching of two stages or more is adopted, but 90% or more of the critical stretching ratio, preferably 92 to.
Stretching is performed at 96%. Here, the critical draw ratio is the maximum draw ratio that can be drawn for 5 minutes without yarn breakage.

The total draw ratio is 3.5 to 6.5 times, usually 4.0 to 6.0 times. The stretching temperature is characterized in that the final stretching temperature is 210 ° C. or higher, preferably 215 to 250 ° C., which is a high temperature.

A heat relaxation treatment is carried out subsequent to the stretching. Usually, the heat treatment is carried out by relaxing 8 to 12% between the final stretching roll and the relaxing roll arranged thereafter.
Since the relaxation heat treatment is substantially performed on the final stretching roll, the temperature is 210 ° C or higher, preferably 215 to 250 ° C.
It is.

Thus, the high-strength polyamide fiber obtained by the method of the present invention has a strength of 10.0 g / d or more, a breaking elongation of 20% or more, and a boiling water shrinkage ratio of less than 10.0%. It also has excellent strength retention and fatigue resistance.

Therefore, the high-strength polyamide fiber of the present invention is particularly useful as a rubber-reinforcing fiber by taking advantage of the above excellent properties.

That is, the high-strength polyamide fiber of the present invention has a small strength reduction when embedded in rubber and vulcanized, and a vulcanized cord having high strength can be obtained. And when using such a high-strength vulcanized cord, it is possible to reduce the number of cords as a tire reinforcing material, reduce the number of pluses of the woven fabric, and use a cord in which the fineness of the fiber is lowered in advance. You can

In any case, the weight of the fiber can be reduced without impairing the reinforcing function and the weight of the tire can be reduced.

The high-strength polyamide fiber of the present invention is
When used as a fiber for fishing nets, it has excellent durability due to its high toughness and good transparency,
Demonstrates optimal yarn characteristics.

[0070]

EXAMPLES Hereinafter, the constitution and effects of the present invention will be described more specifically with reference to examples.

The definitions and measuring methods of the fiber structure parameters, fiber physical properties, tire cord characteristics and the like described in the above and the following examples are as follows: (1) Sulfuric acid relative viscosity (η _r ) Sample 2. 5 g was dissolved in 98% sulfuric acid 25 cc and measured at 25 ° C. using an Ostwald viscometer.

(2) Strength (T / D), elongation at break (E) JIS L-1017, 7.10 using a "Tensilon UTL-4L" type tensile tester (manufactured by Orientec Co., Ltd.).
It measured according to 5.

(3) Shrinkage rate of boiling water (Sw) It was measured according to JIS L-1017, 7.14.

(4) Toughness The strength (g / d) and the cutting elongation (%) obtained above were calculated by the following formula.

(Strength) × (Cutting Elongation) ^1/2 (5) GY Fatigue Life Ratio Measured according to JIS L-1017, 3.2.2.1A, and calculated as 100 corresponding Comparative Example.

[Examples 1 to 8 and Comparative Examples 1 and 2] Polycapramide having a sulfuric acid relative viscosity of 3.60 was dried to a water content of 0.2% or less, then fed to a spinning machine and melted at a spinning temperature of 285 ° C. .

The molten polymer was then filtered in a spin pack through a non-woven metal filter having pores of about 20μ and spun through the spinneret pores.

A heating cylinder having a length of 20 cm was installed immediately below the mouthpiece, and the atmosphere temperature in the heating cylinder was set to 310 ° C.

Next, the unstretched yarns to which the water-based emulsion oil agents shown in Table 1 were applied by slit nozzles were respectively taken up by a take-up roll at a speed of 1000 m / min, and the drawn-up yarns were not wound up once. It was continuously stretched.

At that time, the time at which the water-based emulsion oil was applied and the time until the draw point occurred were changed to 0.01 to 0.05 seconds as shown in Table 2.

The drawing is a multi-step hot drawing of two or more steps, and the total draw ratio is 5.10 times. In addition, the stretching temperature was set to a final stretching temperature of 215 to 225 ° C. as shown in Table 2, and a thermal relaxation treatment subsequent to the stretching was performed to relax by 8% between the final stretching roll and the relaxing roll arranged thereafter. Went down. This relaxation heat treatment was performed substantially on the final stretching roll, and was performed at the same temperature as the final stretching temperature.

Regarding the polyamide fiber obtained above,
Table 2 also shows the spinning conditions and the fiber properties and fiber yield of the obtained drawn yarn.

[Comparative Examples 1 and 2] In Examples 1 to 8 described above, the time point at which the water-based emulsion oil was applied and the time to the draw point occurrence point were 0.1 as shown in Table 2.
Regarding polyamide fibers obtained in the same manner except that the length was changed to 0 to 0.15 seconds, Table 2 also shows the spinning conditions and the fiber properties and fiber yield of the obtained drawn yarn.

Example 9 A polycapramide having a relative viscosity of sulfuric acid of 3.60 was dried to a water content of 0.2% or less, then fed to a spinning machine and melted at a spinning temperature of 285 ° C.

The molten polymer was then filtered in a spin pack through a non-woven metal filter having pores of about 20 μ and spun through the spinneret pores.

A heating cylinder having a length of 20 cm was installed immediately below the base, and the atmosphere temperature in the heating cylinder was set to 310 ° C.

Next, the water-based emulsion oil agent (a) shown in Table 3 was applied by a slit nozzle, and then the non-water-based oil agent was applied in the pre-stretch zone, and then the undrawn yarn was taken by a take-up roll at a speed of 1000 m / min. And the drawn yarn was continuously stretched without being once wound.

At that time, the time from the time when the aqueous emulsion oil was applied to the time when the draw point occurred was 0.02 seconds.

The drawing was a multi-step hot drawing of two or more steps, and the total draw ratio was 5.10 times. The stretching temperature is the final stretching temperature of 210 ° C., and further, the stretching is followed by a thermal relaxation treatment,
It was performed under 8% relaxation between the final stretching roll and a relaxing roll arranged thereafter. This relaxation heat treatment was substantially performed on the final stretching roll, and the temperature was 210 ° C.

Table 2 also shows the spinning conditions and the fiber properties and fiber yield of the obtained drawn yarn.

Next, the above Examples 1 to 9 and Comparative Examples 1 to 1
Each polyamide fiber obtained in No. 2 was subjected to undertwisting 39 times per 10 cm, and then two cords were combined from below and the same number of overtwisting was performed in the opposite direction to the undertwist to obtain a raw cord.

For each of these raw codes, Ritzler (US)
An adhesive was applied and subsequently heat treated using a "Computerator" dipping machine.

The RFL liquid was used as the adhesive, and the liquid concentration and the draining conditions were adjusted so that the adhesion amount was about 5% by weight.

The heat treatment condition is that the drying zone is 160 ° C.
After passing a fixed length for 20 seconds, a heat treatment zone at 235 ° C. was stretched for 40 seconds so that the stress (value obtained by dividing the tension by the fineness of the dip cord) at the exit of the heat treatment zone was 1 g / d. .

Next, in the normalizing zone, 23
Heat treatment was applied at 0 ° C. for 40 seconds with 1% relaxation. With respect to each of the obtained dip cords, characteristics as tire cords were measured, and the results are also shown in Table 2.

[0096]

[Table 1]

[Table 2] As is clear from the results of Table 2, the high-strength polyamide fiber of the present invention can be efficiently manufactured while satisfying the fiber physical properties aimed at by the present invention.

The dip cord using the high-strength polyamide fiber of the present invention, when embedded in rubber and subjected to vulcanization, has high strength and high elongation, that is, high toughness and thermal dimensional stability. It is clear that the vulcanized cord is excellent in fatigue resistance and good in fatigue resistance.

[0098]

As described above, the high-strength polyamide fiber of the present invention has high strength and excellent strength retention and fatigue resistance. According to the method for producing a high-strength polyamide fiber of the present invention, High strength polyamide fibers having the above properties can be produced by an efficient process using an aqueous emulsion oil.

The high strength polyamide fiber of the present invention is
Utilizing its high strength and excellent strength retention and fatigue resistance, it is particularly useful for rubber materials such as belts and hoses and rubber cords such as tire cords, especially when applied as tire cords. In addition, the fiber structure is less likely to change due to thermal and mechanical stimuli during the processing step and running of the tire, and the initial fiber physical properties can be effectively retained.

Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI Technical display area D06M 101: 34

Claims (5)

[Claims] 1. A high-strength polyamide fiber having a strength of 10.0 g / d or more, a breaking elongation of 20% or more, and a boiling water shrinkage ratio of less than 10.0%. 2. A method for producing a high-strength polyamide fiber by applying an aqueous emulsion oil agent to a polyamide unstretched yarn and then hot drawing the same, which occurs when the aqueous emulsion oil agent is applied and by the hot drawing. A strength of 10.0 g / d or more, a cutting elongation of 20% or more, which is characterized by performing hot stretching immediately after applying the aqueous emulsion oil so that the time to the draw point is 0.05 seconds or less. Boiling water shrinkage is 10.0%
A method for producing a high-strength polyamide fiber which is less than. 3. The high-strength polyamide fiber according to claim 1, wherein an aqueous emulsion oily agent is applied to the polyamide unstretched yarn, and a non-aqueous oily agent is further applied in the pre-stretch zone, followed by immediate hot drawing. Manufacturing method. 4. A water-based emulsion oil agent comprising a hydrogenated castor oil ethylene oxide adduct in which the number of moles of ethylene oxide added is 25 moles or less and the number of carbon atoms in the alkyl chain of the adduct is 8 or more. The method for producing high strength polyamide fiber according to claim 2 or 3, characterized in that the content is 10% by weight or more. 5. The hot drawing is a multi-step drawing of two or more steps,
And the drawing temperature is 210 degreeC or more, The manufacturing method of the high strength polyamide fiber in any one of Claims 2-4 characterized by the above-mentioned.