JP3476262B2 - High toughness polyhexamethylene adipamide fiber and method for producing the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-strength polyamide fiber suitable for use in the field of rubber reinforcement such as tire cords and a method for producing the same. For more details,
The present invention relates to a polyhexamethylene adipamide fiber having high breaking energy at the time of rubber reinforcement and excellent in fatigue resistance, and a method for producing the same.

[0002]

BACKGROUND OF THE INVENTION Polyamide fibers are used in various industrial applications because they have high strength, high toughness, and excellent fatigue resistance and impact resistance. Above all, it has been used as a rubber reinforcement for tire cords and the like, particularly for bias tires such as heavy trucks and buses. Recently, in order to improve the performance of tires, in addition to demanding higher strength, it is rather excellent in fatigue resistance,
So-called plunger energy (JIS D 423
There has been an increasing demand for safety performance, such as increasing 0). Plunger energy is the breaking energy when a tire is stepped on by the tip of a rod, and this is done by increasing the breaking energy of the tire cord that is mainly responsible for strength in the tire fiber-reinforced rubber composite. Can be strengthened.

In order to meet the demand for such tire cords, proposals have been made to increase the toughness of polyhexamethylene adipamide fibers, that is, breaking energy. JP-A-4-185711 and JP-A 5-1
In Japanese Patent No. 56315, the adhesion rate of the finishing agent for fibers is 1.
A large amount of 6% or more is applied, and at the end of the thermal multi-stage drawing, a low relaxation treatment is performed at a low temperature of 200 ° C. or less, and a thermal stress value is 0.5.
It is disclosed that the breaking energy value of the adhesive treatment cord, the rubber vulcanization cord, and the fatigue cord is increased by using the fiber of the tire cord as a fiber increased to 5 g / d or more. That is, the adhesiveness of the fiber surface is controlled by using a large amount of finishing agent, and the toughness reduction due to the thermal stretching in the adhesive treatment step is suppressed by the thermal stress, thereby breaking the cord in the rubber composite such as a tire. It was possible to increase the energy.

However, increasing the amount of the finishing agent for fibers adhered to the tube fatigue test (JISL-10173.
This leads to a decrease in fatigue resistance as evaluated by the cyclic extension compression strain test represented by 2.2.1A). Further, along with the increase in manufacturing cost and deterioration of the manufacturing environment due to the heavy use of relatively expensive finishing agents for fibers, the twisting when processing the yarn of polyamide fiber for tire cord, the dripping stain of the oil agent in the weaving process, etc. However, there is a problem that the processing process performance is deteriorated.

[0005]

An object of the present invention is a high-strength polyamide fiber suitable for reinforcing rubber such as tire cords, which has high breaking energy, that is, high toughness when processed for rubber reinforcement. Another object of the present invention is to provide a fiber and a method for producing the same, which exhibits high fatigue resistance without adding a large amount of finishing agent for the fiber.

[0006]

The present inventors have made it possible to maintain a high breaking energy, that is, toughness, of a cord in a rubber composite without adding a large amount of a finishing oil agent by appropriately adjusting a stretching process. At the same time, we found that the fatigue resistance is improved, and furthermore, by allowing the finishing agent with specific properties to exist on the fiber surface, the adhesion with the adhesive and rubber can be controlled without adding a large amount of finishing agent. However, the inventors have found that high toughness in the rubber composite can be achieved by avoiding the concentration of stress, and have reached the present invention.

That is, according to one aspect of the present invention, a fiber made of polyhexamethylene adipamide having a sulfuric acid relative viscosity ηr of 2.8 or more and 3.7 or less is melt-spun, cooled, and drawn using a drawing roll. In the method of producing by multi-stage hot drawing, 0.5 to 1.5% by weight of a finishing agent is applied to a yarn which is melt-spun and cooled, and then mirror-finished and satin-finished in the first stage drawing. Using a take-up roll consisting of two surface areas, the yarn is taken up at the mirror-finished surface, passed from the satin-finished surface to the next godet roll, and subsequently the total draw ratio (DR) is 4.5-6. 9. A high toughness polyhexamethylene adipamide fiber characterized by being subjected to relaxation heat treatment within a range of the following formula with a final godet roll temperature (T) of 150 ° C. to 50 ° C. Manufacturing method 0.00028 × T + 0.99 ≧ RR ≧ -0.000
28 × T + 0.956, and another aspect of the present invention is the sulfuric acid relative viscosity η.
It consists of polyhexamethylene adipamide having r of 2.8 or more and 3.7 or less, and has a breaking strength of 9.5 to 12.5 g / d,
The breaking elongation is 16 to 21%, the thermal stress at 230 ° C. is 0.55 g / d or more, and the finishing agent adheres to the fiber surface in an amount of 0.5 to 1.5% by weight. A high toughness polyhexamethylene adipamide fiber having a water absorption time of 3 to 120 seconds, wherein the finishing agent is (1) thiodipropionic acid and 12 carbon atoms.
Of 18 to 40 parts by weight of a diester with a monohydric alcohol, and (2) ethylene oxide (10 to 45 mol) added to castor oil or hydrogenated castor oil having 1 carbon atom.
2-18 fatty acid ester or partial ester 15
To 30 parts by weight, and (3) 10 to 30 parts by weight of an ether of a C 12-18 monohydric alcohol and an ethylene oxide / propylene oxide copolymer, and the above-mentioned finishing agent ( 1), (2), (3)
Is 100 parts by weight in total, which is the polyhexamethylene adipamide fiber according to claim 1. The finishing agent is the polyhexamethylene adipamide fiber according to claim 2, further comprising (4) an alkanolamine in an amount of 0.1 to 10 parts by weight.

In the method for producing high toughness polyhexamethylene adipamide fiber of the present invention, the adhesion rate of the finishing agent to the fiber is 0.5% by weight or more and 1.5% by weight or less. 0.
If it is less than 5% by weight, it is not possible to guarantee uniform application to the fiber made of multifilaments, and stable production is not possible especially with fibers for industrial materials such as tire cords. Also,
If it exceeds 1.5% by weight, it is effective in increasing the breaking energy of the adhesive-treated cord and the rubber vulcanized cord, but there is a problem that sufficient fatigue resistance cannot be obtained due to an excessive amount of finishing agent.

Hitherto, by increasing the amount of the finishing agent attached, the penetration of the RFL adhesive into the fiber is suppressed, and the decrease in the elongation of the adhesive treatment cord and the vulcanization cord is prevented. In the production method of the present invention, by appropriately adjusting the stretching step, uniform stretching and uniform molecular orientation of the fibers used for the tire cord are promoted, and as a result, adhesive treatment or vulcanization is performed without a large amount of finishing agent being attached. It has become possible to increase the fiber breaking energy after the heat tension step such as treatment.

In the production method of the present invention, a device as illustrated in FIG. 1 is used to melt and discharge the polymer yarn from the spinneret, apply the finishing agent to the cooled polymer yarn, and then apply it to the take-up roll (8). It can be manufactured by performing take-up and hot multi-stage drawing between the take-up roll and the godet roll. The first stage drawing is the take-up roll (8) and the two godet rolls (9).
In the first stage stretching, the stretching is started from the surface of the take-up roll, and the thinning is gradually carried out by applying two godet rolls.

In order to gradually perform the drawing and thinning, a take-up roll is used as a take-up roll, the surface of which the yarn is taken up is mirror-finished, and the surface area where the yarn is passed to the next godet roll is satin finished. In the yarn take-up portion, the yarn is wrapped on the mirror-finished surface portion and is sufficiently gripped. Next, in the satin-finished portion, the yarn starts to be stretched while sliding, and is subjected to two godet rolls to complete the first-stage stretching. Therefore, the slow stretching of the first stage can be easily achieved.

In the manufacturing method of the present invention, the surface of the take-up roll is hardened by, for example, chrome plating, and the surface roughness Ra thereof is 0.5 or less in mirror finishing and 1 or more in satin finishing. By processing to 7 or less, it is possible to preferably control the gripping and sliding of the yarn. FIG. 2 shows an example of data obtained by measuring the running speed of a yarn with a laser Doppler yarn speed measuring device (manufactured by DANTEC).

In the conventional method (a), the running speed of the yarn changes only between the take-up roll and the two godet rolls, and the drawing thinning occurs sharply. The running speed of the yarn starts to increase and the running speed of the yarn gradually increases over the two godet rolls, and the drawing is gradually drawn. According to this method, it is possible to secure the uniformity of stretching between filaments, especially in the case of fibers made of multifilaments.

In the manufacturing method of the present invention, the yarn is taken up on the mirror-finished surface and passed from the matte-finished surface to the next godet roll, and then the total draw ratio (DR) is continuously changed to the winding speed ( The range of the equation is 7.1-WR / 2860 ≧ DR ≧ 6-WR / 2860 depending on the (WR), but the value is 4.5 to 6.9, and more preferably 4.95 to 6. At 75, stretch in multiple stages.

Further, for the stability of the drawing process, a take-up roll whose surface temperature T (° C.) satisfies the following general formula is used so that the molecular chains of the amorphous part of the take-up yarn can sufficiently move in segments. . Tgc−20 ≦ Ts ≦ Tgc + 40 However, here, Tgc means the temperature at which the storage elastic modulus of the yarn drawn by the take-up roll completes a sharp decrease in the glass transition region, and is obtained from the chart illustrated in FIG. 3. Also,
The storage elastic modulus was DDV-01FP Rheovibron manufactured by Orientec Co., Ltd., the yarn length was 2 cm, and the initial load was 0.027.
Each single yarn of a multifilament yarn was measured at 35 Hz under conditions of g / d and a temperature rising rate of 5 ° C./min. In the manufacturing method of the present invention, in the relaxation heat treatment, the temperature (T) of the final godet roll is 150 ° C. or lower and 50 ° C. or higher, and the relaxation ratio (RR) is in the range shown by the following formula. −0.00028 × T + 0.99 ≧ RR ≧ −0.000
28 × T + 0.956 In this way, by the relaxation heat treatment by the production method of the present invention, the high toughness polyhexamethylene adipamide fiber having a thermal stress of 0.55 g / d or more at 230 ° C. after multi-stage drawing. Can be obtained.

If the thermal stress is less than 0.55 g / d, the yarn stretch is too large in the heat tension process such as adhesive treatment or vulcanization which is carried out at a temperature of about 230 ° C. The fiber breaking energy after the processing step is significantly reduced. Therefore, by fixing the molecular orientation at a low temperature after the multi-stage stretching, it becomes possible to suppress the reduction in breaking energy in the processing step.

When the relaxation heat treatment temperature is 150 ° C. or higher, the thermal stress value becomes 0.55 g / d or less. The lower the relaxation heat treatment temperature is, the better, but industrially it becomes difficult to control the temperature near room temperature. Therefore, it is desirable to set the temperature to 50 ° C. or higher. More preferably, it is 70 ° C. or higher and 120 ° C. or lower. At this time, the relaxation ratio (RR: winding speed /
If the final godet roll velocity) is too low than the range shown in the above formula, the molecular orientation is not sufficiently fixed, and the required thermal stress value cannot be obtained. A higher relaxation ratio is more advantageous for increasing the thermal stress, but if it exceeds the upper limit shown in the above formula, the breaking energy of the fiber is rather lowered.

On the other hand, if the relaxation ratio is too high, the winding tension between the final godet roll and the winder becomes too high, and the winding shape may deteriorate. On the other hand, if the thread becomes too low, the thread will loosen and cannot be wound. The relaxation ratio may be set within the range of the above formula so that an appropriate winding tension (for example, 0.1 to 0.3 g / d) is obtained. By fixing the orientation of the molecules by this method, it is possible to secure the uniform orientation of the molecules and further the filaments in the heat tension step such as the adhesive treatment or the vulcanization treatment together with the uniform stretching by the slow stretching method described above. it can. As a result, stress concentration on weak points in the breaking test is reduced, and breaking energy can be improved.

In the manufacturing method of the present invention, a spinning and drawing machine is used as shown in FIG.
Although it is preferable to use a direct spinning / drawing machine as exemplified in, a spinning and drawing machine may be used separately. The polymer can be supplied to the spinning machine either by directly feeding the polymer from the polymerization to the spin head (1) in FIG. 1 or by remelting the pelletized polymer with an extruder and then feeding the polymer to the spin head. But it's okay.

In the production method of the present invention, it is preferable that the stretching is carried out in multiple stages by an apparatus as shown in FIG. When two or more stages are stretched, the godet roll needs to have three or more stages, and preferably has four or more stages. In the three-stage godet roll method,
The final relaxation heat treatment may be performed with a relaxation ratio between the 3-godet roll and the winder, and in the 4-stage godet roll method, the relaxation ratio may be distributed between the 3-godet roll and the 4-godet roll and between the winders. Further, the second stage drawing is performed between the two godet rolls and the three godet rolls, and the drawing temperature of the second godet roll is 1
It may be selected from the range of 50 ° C to 250 ° C. Also, the second
The step draw ratio may be selected from the range of 1.6 to 2.2.

The polyhexamethylene adipamide according to the present invention is obtained by a polycondensation reaction of adipic acid and hexamethylenediamine, and is a commonly used additive, for example, an inorganic phosphorus compound such as phosphoric acid or sodium hypophosphite. , Phenylphosphonic acid, organic phosphorus compounds such as triphenylphosphite, phosphorus-nitrogen complex salts, polymerization catalysts such as phosphorus-nitrogen compounds, copper acetate, copper bromide, copper iodide, 2-mercaptobenzimidazole copper complex salts, etc. Copper compounds, 2-mercaptobenzimidazole, tetrakis- [methylene-3
-(3,5 di-t-butyl-4-hydroxyphenyl)
-Propionate] -Heat stabilizers such as methane, light stabilizers such as manganese lactate and manganese hypophosphite, titanium dioxide,
Matting agents such as kaolin, cyclic phenols, ethylenebisstearylamide, partial methylol derivatives thereof, lubricants such as calcium stearate, plasticizers and crystallization inhibitors may be included.

The degree of polymerization of the polymer must be 2.8 or more and 3.7 or less in sulfuric acid relative viscosity ηr. If the relative viscosity of sulfuric acid is low, the required breaking strength cannot be obtained, and if the relative viscosity of sulfuric acid is high, spinning becomes difficult. The more preferable range of sulfuric acid relative viscosity is 2.9 or more and 3.4 or less. In addition, during polymer polymerization, the base concentration in the polymer may be increased in order to control the polymer structure, particularly the aggregate structure of the amorphous portion. As a method thereof, there is a method of directly adding an organic metal salt such as sodium hydroxide or sodium adipate to the polymer in the polymerization process, or a method of adding the organic metal salt by dissolving it in a finishing agent or the like and then adhering it after the fiber formation.

Further, in the case of a polyamide fiber composed of a condensation product of a diamine such as hexamethylene adipamide and a dicarboxylic acid, it can also be achieved by adding the diamine component in a large amount relative to the dicarboxylic acid component. At this time, since the vapor pressure of the aliphatic diamine such as hexamethylenediamine is generally low, it is easily scattered during the amidation reaction, but efficient production can be achieved by collecting and recycling the scattered diamine.

The production method of the present invention determines the total draw ratio based on the winding speed and the degree of polymerization, that is, the viscosity such as relative viscosity of sulfuric acid, and the properties of the undrawn yarn determined by the melt spinning method and the subsequent cooling method. In general, lowering the total draw ratio for increasing winding speed and / or increasing relative viscosity of sulfuric acid results in polyhexamethylene adipamide fibers of desired strength.

For example, in order to obtain a desired breaking strength with a large increase in winding speed, 0.00035 times / 1 m · m
A stretching ratio obtained by subtracting the value of in ^-1 may be used. Further, by the above-mentioned drawing temperature and drawing method, a fiber having high toughness can be obtained without significantly lowering the breaking elongation. In particular, fibers used for applications such as tire cords can be manufactured by setting the total draw ratio so that the breaking strength of the fibers is 9.3 g / d or more and the breaking elongation is 12% or more.

Examining the state of adhesion between the RFL adhesive and the rubber via the RFL adhesive and the polyhexamethylene adipamide fiber, when a part of the fiber composed of the multifilament is fixed by the adhesion and tensile stress or the like is applied, Another factor that reduces the toughness is that it becomes a stress concentration point and that the breaking strength and the breaking elongation decrease, that is, the toughness decreases. The present inventors have found that the reduction in toughness can be further suppressed by suppressing the penetration of the RFL adhesive into the raw cord.

In the past, by increasing the amount of the finishing agent attached, the penetration of the RFL adhesive into the fiber was suppressed, and the decrease in the elongation of the adhesive treatment cord and the vulcanization cord was prevented. However, in the present invention, permeation suppression can be achieved by allowing a finishing agent having a specific property to exist on the fiber surface.
That is, the polyhexamethylene adipamide fiber obtained by the production method of the present invention has an adhesion amount of the finishing agent of 10%.
The water absorption time measured by the method of dropping water on the nylon base fabric is 3 seconds or more and 120 seconds or less.

If the water absorption time is 3 seconds or more, the polyhexamethylene adipamide fiber is dipped in the RFL adhesive solution even if the amount of the finishing agent attached is 0.6% to 1.5%. The penetration of the RFL adhesive in the applying step can be suppressed, and the toughness of the fiber can be prevented from lowering. On the other hand, R
If the FL adhesive is repelled, poor adhesion will occur, so the water absorption time must be 120 seconds or less.

In the present invention, the adhesion rate of the finishing agent to the fibers must be 0.5% by weight to 1.5% by weight. If it is less than 0.5% by weight, uniform application to multifilament fibers cannot be guaranteed, and stable production is not possible especially with fibers for industrial materials such as tire cords. Also,
If it exceeds 1.5% by weight, it is effective in increasing the breaking energy of the adhesive treatment cord and the rubber vulcanization cord, but there is a problem that sufficient fatigue resistance cannot be obtained due to an excessive amount of finishing agent.

The composition of the finishing agent controls the water absorption,
Any other general stretch processing oil may be used as long as it satisfies characteristics such as stretchability, heat resistance and supply stability. Further, it may be either an aqueous emulsion type mainly consisting of a smoothing agent and an emulsifier, or a non-aqueous type mainly containing a smoothing agent, but its hydrophilicity and blending amount in order to control the water absorption by the finisher to a desired water absorption time. The composition can be designed by selecting.

For example, examples of the leveling agent include esters of higher alcohols such as oleyl oleate and isostearyl oleate with higher fatty acids, dioleyl adipate,
Ester of dibasic acid such as diisostearyl sebacate and higher alcohol, ester of aromatic carboxylic acid such as triisodecyl trimellilate and higher alcohol, ester of thiodipropionic acid and higher alcohol, and neopentyl glycol Laurate, glycerin trioleate, pentaerythritol tetradecanoate,
Polyhydric alcohols such as sorbitan tristearate and higher fatty acid esters are used. In a smoothing agent using an ester composed of a polyhydric alcohol or / and a dibasic acid or the like, the degree of esterification is a factor that controls water absorption. Further, as an example of the emulsifier, a nonionic surfactant is mainly used, and ethylene oxide adducts of polyhydric alcohols such as glycerin and sorbitan, higher fatty acids such as oleic acid and lauric acid, and natural fats and oils such as castor oil are used. And a compound obtained by adding ethylene oxide to a higher alcohol, a higher amine or an alkylphenol. The amount of ethylene oxide added to the emulsifier is a factor that controls the water absorption. Also, as other ingredients, heat stabilizers, antioxidants,
An antistatic agent, a polymer activator and the like are preferably contained, and it is also preferable to add an alkyl phosphate and a metal salt thereof, an alkyl sulfonate and a metal salt thereof.

In particular, when a diester of thiodipropionic acid and a monohydric alcohol having 12 to 18 carbon atoms is selected as a smoothing agent component of the finishing agent, a finishing agent having good heat resistance can be easily assembled. Furthermore, a nonionic surfactant is blended for emulsification, filament convergence and uniform adhesion, but if the amount of the smoothing agent is too large, it becomes impossible to emulsify and the uniform adhesion is impaired. The smoothness is impaired and water absorption is promoted at the same time. As the nonionic surfactant, a fatty acid ester having 12 to 18 carbon atoms or a partial ester of castor oil or hydrogenated castor oil to which ethylene oxide (10 to 45 mol) is added, and 12 to 18 carbon atoms are used.
By combining the monohydric alcohol with an ether of an ethylene oxide / propylene oxide copolymer, it becomes possible to control water absorption while being excellent in emulsifying property, converging property, uniform adhesion property and heat resistance.

That is, the compounding amount of (1) diester of thiodipropionic acid and monohydric alcohol having 12 to 18 carbon atoms was 40 to 70 parts by weight, and (2) ethylene oxide (10 to 45 mol) was added. 15 to 30 parts by weight of fatty acid ester or partial ester having 12 to 18 carbon atoms of castor oil or hydrogenated castor oil, and (3) monohydric alcohol having 12 to 18 carbon atoms and ethylene oxide /
10 to 10 ether with propylene oxide copolymer
If a finishing agent having a composition of 30 parts by weight and 100 parts by weight of the finishing agents (1), (2) and (3) is used, the water absorption performance is suppressed and the RFL adhesive on the fiber surface is suppressed. It is possible to obtain a more preferable high toughness polyhexamethylene adipamide fiber that can suppress permeation.

Further, water absorption can be suppressed by adding an alkanolamine to the finishing agent component. However, if the blending amount is too large, the emulsion stability and the uniform stability as an oil agent will be impaired, and it will not be put to practical use. That is, the compounding composition in which 0.1 to 10 parts by weight of (4) alkanolamine is added is preferable. Further, in order to enhance the stability of the finishing agent, it is preferable to mix it in the form of a neutralized salt, and it is particularly preferable to mix it in the form of a neutralized salt with an alkyl phosphate.

The method of applying the finishing agent may be an oiling roll method, an oiling nozzle method, or a combination thereof. After-oiling performed after stretching and relaxation heat treatment may be used together. Furthermore, the non-aqueous finishing agent may be diluted and imparted using a petroleum-based organic solvent or the like. As another condition, in the processing step for the rubber-reinforced cord, the fiber is exposed to extreme conditions such as heat, tension, and adhesive. Especially, in the adhesive processing step, the structure of the fiber is greatly changed. By properly selecting the conditions, the fiber performance can be sufficiently exhibited.

According to the present invention, the thermal stress at 230 ° C. is 0.55 g / d or more, and for example, in the case of a fiber having a fineness of about 1890 denier, the vulcanized cord after being placed in rubber and vulcanized Breaking energy is 49 kg · cm
As described above, a sufficient performance value is shown in the plunger energy test, which is a tire breaking strength test. In addition, the fatigue cord breaking energy after the Goodyear tube fatigue test, which is normally used as a fatigue test for tire cords, at a bending angle of 150 ° for 23 hours is 40 kg / cm.
As a result, fatigue resistance is improved (however,
The required cord energy is proportional to the fineness of the fiber used for the cord).

Furthermore, since the polyhexamethylene adipamide fiber obtained by the production method of the present invention does not have an excessively large amount of finishing agent applied, problems such as oil dripping in the tire cord processing step can be eliminated. When it is processed into a reinforcing cord, it is exposed to extreme conditions such as heat, tension, and adhesives, especially conditions that significantly change the structure of the fiber in the adhesive treatment process, but since it has excellent physical properties, the process conditions are It can be selected appropriately and the performance of the fiber can be sufficiently exhibited.

[0038]

EXAMPLES Next, the present invention will be described in more detail by way of examples. The definitions of various terms used in the present invention and methods for measuring physical properties will be described. (1) Water absorption evaluation According to the dropping method shown in JIS-L-1096 and JIS-L-1018. The specific nylon base fabric used here is a plain weave fabric (2 denier / 70 filament untwisted yarn with a warp and weft density of 53 yarns / inch) (2
(0 × 20 cm) after degreasing and refining, emulsifying or dipping in a finishing agent whose concentration is adjusted by diluting with a non-aqueous diluent, attaching to a frame so as not to sag, and air-drying, and further at hot air dryer 60 ° C. It was completely dried, and the amount of the coating agent applied was 10%.

The water absorption time is a value measured by dropping 0.5 μl of distilled / ion-exchanged water from a height of 1 cm from the surface of the base fabric and measuring the time from the dropping until the specular reflection on the water drop surface cannot be visually confirmed. (Average value repeated 10 times). (2) Sulfuric acid relative viscosity This is the relative viscosity at 25 ° C. of a solution prepared by dissolving 95.5% by weight sulfuric acid in a polymer concentration of 1.0 g / dl. (3) Breaking strength, breaking elongation, intermediate elongation of raw yarn and cord,
The breaking energy measuring chamber is maintained at a temperature of 25 ° C. and a humidity of 55 RH%. As a measuring device, Shimadzu Corporation's trade name Autograph S-100 is used. Using the fiber obtained in the example as a yarn, twist of 80 times / m was added to the yarn, and a 25 cm sample was obtained at a descending speed of 30 cm / min. Raw code and processing code follow JISL 1017. Breaking energy is S-S
The area of the curve was determined using an integrator. The intermediate elongation is an elongation (%) at a load w (Kg) defined by the following formula.

W = 4.5 × d2 / d1 (d2: sample denier, d1: standard denier; raw yarn 840d, cord 1680d) (4) 230 ° C. thermal stress value The thermal stress measuring device is manufactured by Kanebo Engineering Co., Ltd. Was measured using a trade name KE-2. Length 20 from polyhexamethylene adipamide fiber consisting of multifilaments
Five filament single yarns of cm are extracted, the ends of the bundle of filament single yarns are tied together to form a ring, and the loop is set in a measuring instrument. In this way, the thermal stress of 10 filament single yarns is measured. Initial load 0.05g / d, heating rate 10
It is measured under the condition of 0 ° C./min, the tension Th at 230 ° C. is obtained, and the thermal stress value (g / d) is calculated according to the following formula.

230 ° C. thermal stress value = Th / 2 × 5 × filament single yarn fineness (denier) (5) Dry heat shrinkage (dry yield) A sample with a code of 1.2 m is free for 30 minutes in an air oven at 160 ° C. Thread length (S) c after shrinkage and after heat treatment
It is calculated from m according to the following formula. Dry heat shrinkage (%) = 100-S / 100 × 100 (6) Adhesion amount of finishing agent (OPU) A fiber sample of 2 ± 0.002 g was weighed and added with 3 cc of dichloromethane and left for 90 seconds. Squeeze the dichloromethane into an aluminum dish. This operation is repeated 3 times, and the obtained dichloromethane solution is heated at 120 ± 1 ° C. to evaporate dichloromethane. Weight of residue R
(G) was measured, and the adhesion amount (%) of the finishing agent was calculated by the following formula.

Finishing agent adhesion amount (%) = R / 2 × 100 (7) The raw cord raw yarn is twisted 32 times / 10 cm undertwisted, and then the two obtained lower twisted yarns are twisted The cord was twisted several times for 10 times and was used as a raw cord. (8) Processing code As a raw code, using a three-oven hot stretch device (computer) illustrated in FIG. 4, resorcin-
Formaldehyde-latex adhesive (RFL adhesive)
The processing code was obtained by performing the dipping process of 15 m / min. The conditions are as follows.

A) Normal temperature method Temperature tension First zone 160 ° C. 2.25 Kg / code Second zone 232 ° C. 4.5 Kg / code Third zone 232 ° C. 2.9 Kg / code B) Low temperature method Temperature tension first Zone 160 ° C. 2.25 Kg / code Second zone 222 ° C. 4.5 Kg / code Third zone 222 ° C. 2.9 Kg / code (9) Fatigue code Tube test method according to JIS L-101733.2.2.1A Conforms to the tube inner diameter 12.5mm outer shape 26mm length 226.5mm vulcanization conditions 140 ° C x 40 minutes bending angle 150 degrees internal pressure 3.5Kgf · cm ² rotation speed 850rpm after 1380 minutes of fatigue time, do not damage the cord from the tube To cut it out. The S-S curve was measured with an autograph, and the breaking energy was obtained from the S-S curve area using an integrator. (10) Vulcanized cord A tube was formed in the same shape as the above fatigue cord, except that the vulcanization condition was set to 155 ° C. for 30 minutes, and then the cord was cut out from the rubber so as not to damage it. Measure the S-S curve with an autograph and use the S-S curve with an integrator.
The breaking energy was calculated from the S curve area.

[0044]

[0045]

[0046]

[0047]

[0048]

[0049]

[0050]

[ Examples 1 to 3] Polyhexa having a relative viscosity of sulfuric acid ηr3.1 was obtained by a conventional polymerization method.
A pellet of methylene adipamide was obtained. This polymer
Lett is copper iodide corresponding to a copper content of 80 ppm,
Kalium iodide equivalent to 1300ppm in iodine content
And titanium oxide 15 ppm. This polymer
The moisture content of the pellet is adjusted so that the relative viscosity of sulfuric acid in the spun yarn does not decrease.
The melt spinning machine and drawing machine shown in FIG.
Direct spinning and drawing method using
A xamethylene adipamide fiber was produced. Made at that time
The manufacturing conditions and the finish composition are as follows. -Spinning conditions Polymer discharge rate 435 m / min Spinneret Pore diameter 0.23 mmφ, Pore length 0.23, Number of holes 312 Spinning temperature (spin head temperature) 310 ° C Spinning speed (pre-tension roll peripheral speed) 420 m / min Finishing agent It is as shown in Tables 2, 4, and 5. -Drawing condition take-up roll (hereinafter referred to as 1GD) 90 ° C, peripheral speed 4
24 m / min 2nd godet roll (hereinafter referred to as 2GD) 223
℃, peripheral speed 1304m / min 3rd godet roll (hereinafter referred to as 3GD) 105
C, peripheral speed 2348 m / min Winding speed 2200 m / min Total draw ratio 5.54 (Tgc of the yarn taken up at 1 GD was 78 ° C.) 1 GD rolls take up the yarn as shown in FIG. part
Is a mirror finish, and the part where the roll is handed over to 2GD
Was a satin finish (hereinafter referred to as half satin finish).
As a result, the first two wraps of the thread winding are mirror-finished.
The work part and the laps after that run the satin finish part.
It was 2GD and 3GD all used satin finish. this
Using raw cord obtained by processing the raw yarn obtained in this way,
A hot dip treatment was performed. Raw thread, raw cord, processing cord
Code, vulcanization code, and fatigue code
The physical properties are shown in Table 2. It can be seen that the rupture energy of the vulcanized cord is improved as the water absorption time is increased, which is effective for improving the tire's plunger energy .

Example 4 Stretching was carried out using a 4-stage godet roll method. The conditions are as follows. The composition and application method of the finishing agent are shown in the table.
2, 4, and 5 and the raw code is processed by the low temperature method.
I went there . Other conditions were the same as in Example 1. -Spinning conditions Polymer discharge rate 567 g / min Spinneret Pore diameter 0.23 mmφ, Pore length 0.46, Pore number 624 Spinning speed (pretension roll peripheral speed) 475 m / min-Stretching condition 1 GD 90 ° C, peripheral speed 480 m / min 2GD 215 ° C., peripheral speed 1574 m / min 3 GD 220 ° C., peripheral speed 2833 m / min 4 GD 100 ° C., peripheral speed 2833 m / min Winding speed 2700 m / min Total draw ratio 5.90 (Tgc of the yarn taken up at 1 GD is 81 ° C. Met.)

[Comparative Example 1] A roll having an overall mirror finish was used for 1 GD, and 3 GD was used.
The temperature was 220 ° C., the spinning and drawing were performed under the following conditions, and the dip temperature was low temperature. Other conditions are Example 1
Same as. The results are shown in Table 3 . -Spinning conditions Polymer discharge rate 525 g / min Spinning speed (pre-tension roll peripheral speed) 508 m / min-Stretching conditions 1GD 65 ° C, peripheral speed 513 m / min 2GD 210 ° C, peripheral speed 1457 m / min 3GD 220 ° C, peripheral speed 2769 m / min Mining winding speed 2500 m / min Total stretching ratio is 5.40 The breaking energy of the vulcanized cord is much lower.

[Comparative Example 2] A roll having an overall mirror finish was used for 1GD, and spinning was performed under the following conditions as a relaxation treatment at a 3GD temperature of 105 ° C, and the dip temperature was low. Other conditions are examples
Same as 1 . The results are shown in Table 3 . -Spinning conditions Polymer discharge rate 525 g / min Spinning speed (pre-tension roll peripheral speed) 493 m / min-Stretching conditions 1GD 65 ° C, peripheral speed 498 m / min 2GD 220 ° C, peripheral speed 1414 m / min 3GD 105 ° C, peripheral speed 2688 m / The take-up speed 2500 m / min The total draw ratio is 5.40 Even if the final godet roll 3GD is subjected to the low temperature relaxation treatment, the breaking energy of the vulcanized cord cannot reach the target value when the whole mirror finishing roll is used.

[Comparative Example 3] A roll having an overall mirror finish was used for 1 GD, and a relaxation treatment was performed at a 3 GD temperature of 105 ° C. to increase the amount of the finish agent adhering to 2.0% by weight. The dip temperature was low. The other conditions were the same as in Comparative Example 2. The results are shown in Table 3.
Shown in. Although the rupture energy of the vulcanized cord is improved by the amount of the finishing agent attached, the rupture energy of the fatigue cord is reduced and the fatigue resistance is deteriorated.

Comparative Example 4 Table 3 shows the results obtained in the same manner as in Example 2 except that E as shown in Table 5 was used as the finishing agent. The water absorption time is short and the breaking energy of the vulcanized cord cannot reach the target value.

[Comparative Example 5] Table 3 shows the results obtained in the same manner as in Comparative Example 1 except that D shown in Table 5 was used as the finishing agent. Although the water absorption time is long, the thermal stress value is small and the breaking energy of the vulcanized cord cannot reach the target value.

[0058]

EFFECTS OF THE INVENTION The method for producing high toughness polyhexamethylene adipamide fiber of the present invention has a higher cord rupture after adhesion treatment and vulcanization treatment than the conventional one, even without adding a large amount of finishing agent. It is possible to obtain a high-strength polyamide fiber suitable for a rubber-reinforcing cord that exhibits energy and is excellent in fatigue resistance.

[0059]

[0060]

[Table 2]

[0061]

[Table 3]

[0062]

[Table 4]

[0063]

[Table 5]

[Brief description of drawings]

FIG. 1 is an explanatory view schematically showing a test spinning machine and a drawing machine used in Examples.

[Fig. 2] Example of measurement of yarn speed in a multi-stage drawing method using a godet roll

FIG. 3 E ′, tan of single yarn of take-up yarn at 1 GD
Example of δ-T curve

FIG. 4 is a schematic diagram schematically showing a dipping device used in Examples.

FIG. 5 is an explanatory view schematically showing a take-up roll used in Examples.

[Explanation of symbols]

1: Spin head 2: Spinneret 3: Heating tube 4: Filament 5: Cold air chamber 6: Oiling roll 7: Pretension roll 8: Collection roll 9: 2 Godet Roll 10: 3 Godet Roll 11: 4 Godet Roll 12: Winder 21: Tension control roll 22: Tension control roll 23: Adhesive dipping device 24: Tension control roll 25: Tension control roll 26: Tension control roll 27: Tension control roll 28: Dip code winder 29: Supply zone 30: 1st zone (drying zone) 31: Second zone (stretch zone) 32: Zone 3 (Relax Zone) (A): Travel speed of the conventional yarn (B): Running speed of yarn in the slow drawing method

─────────────────────────────────────────────────── --- Continuation of the front page (56) References JP-A-4-185711 (JP, A) JP-A-5-156513 (JP, A) JP-A 63-35822 (JP, A) JP-A 52- 66757 (JP, A) JP-A-6-346319 (JP, A) JP-A-4-185768 (JP, A) JP-A-6-299411 (JP, A) JP-A-4-34074 (JP, A) JP-A-2-145867 (JP, A) JP-A-6-228877 (JP, A) JP-A-7-252727 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) D06M 13/00-13/535 D01F 6/60 D02J 1/22 F Term (4L033, 4L035, 4 L036)

Claims (3)

(57) [Claims] 1. A sulfuric acid relative viscosity ηr of 2.8 or more and 3.7.
Made from the following polyhexamethylene adipamide,
9.5 to 12.5 g / d, elongation at break 16 to 21%
And the thermal stress at 230 ° C is 0.55 g / d or more.
And 0.5 to 1.5 weight of finishing agent on the fiber surface
%, And the water absorption of the finishing agent is 3 to 1 during the water absorption time.
20 tons high toughness polyhexamethylene adipamide
The finishing agent is a fiber, and the finishing agent is (1) a diester of thiodipropionic acid and a monohydric alcohol having 12 to 18 carbon atoms.
0 to 70 parts by weight, and (2) ethylene oxide (1
0 to 45 mol) 15 to 30 parts by weight of a fatty acid ester or a partial ester having 12 to 18 carbon atoms of added castor oil or hydrogenated castor oil, and (3) a carbon number of 12 to 1
A composition containing 10 to 30 parts by weight of an ether of a monohydric alcohol of 8 and a copolymer of ethylene oxide / propylene oxide, and the finishing agent (1),
Polyhexamethylene adipamide fiber, wherein the total of (2) and (3) is 100 parts by weight. 2. The polyhexamethylene adipamide fiber according to claim 1 , wherein the finishing agent further contains 0.1 to 10 parts by weight of (4) alkanolamine. 3. A sulfuric acid relative viscosity ηr of 2.8 or more and 3.7.
A fiber made of the following polyhexamethylene adipamide,
In the method of melt spinning, cooling, and multistage hot drawing using a drawing roll to produce, in the melt spinning and cooled yarn,
The surface of which the yarn is mirror-finished by using a take-up roll comprising two surface regions which are provided with 0.5 to 1.5% by weight of a finishing agent and are then mirror-finished and satin-finished in the first stage drawing. And then handed over from the satinized surface to the next godet roll, and subsequently, the total draw ratio (DR) is 4.5 to 6.
9. A high toughness polyhexamethylene adipamide fiber characterized by being subjected to relaxation heat treatment within a range of the following formula with a final godet roll temperature (T) of 150 ° C. to 50 ° C. Manufacturing method. −
0.00028 × T + 0.99 ≧ RR ≧ −0.0002
8 x T + 0.956