JP3294654B2 - Polyamide fiber - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a polycondensation reaction.
The polyamide from which the raw polymer is prepared, i.e., poly
Acid and base drops during the production of hexamethylene adipamide fiber
Base concentration per kg of polyamide determined by a standard method
1 kg of polyamide whose degree is determined by acid-base titration
Adjustment to be higher than the acid concentration
I do. More specifically, tire cords and bells for rubber reinforcement
High heat resistance, high fatigue resistance, high strength fiber used for tocord, etc.
It relates to industrial materials that are textile materials.

[0002]

2. Description of the Related Art Polyamide fibers have high strength, high toughness, and excellent fatigue resistance and impact resistance, and are therefore used in various industrial applications such as rubber cords for tire cords and belts, computer ribbons and sheets. It is used for belts, sewing threads, fishing nets, various cover sheets, and the like.

With respect to polyamide fibers having improved fatigue resistance, JP-A-58-174623 and JP-A-61-61623 disclose a polyamide fiber.
No. 34216 discloses that the peak temperature of the mechanical loss (tan δ) is 90 ° C. or less and the peak value is 0.10.
A nylon 66 fiber having improved fatigue resistance of 0.14 or less is disclosed. Also, Japanese Patent Application Laid-Open No.
No. 11 discloses a high withstand ratio in which the proportion of an amorphous phase measured by the solid-state NMR method is 50% or more, the ratio of the amorphous phase to the intermediate phase component is 2 or more, and the longitudinal relaxation time of the crystalline phase is 50 seconds or more. Fatigue high-strength polyhexamethylene adipamide fibers are disclosed, but these mainly control the fiber structure by spinning technology, and there is no description or suggestion regarding the polymer composition.

Polyamide fibers having improved impact resistance and knot strength are prepared by blending two or more polymers having high compatibility, by copolymerization, or by adding additives having high compatibility with polyamide. The mainstream is to suppress the degree of crystallinity by blending into a mixture.
These are methods based on lowering the melting point due to the entropy effect and lowering the crystallization rate.

[0005]

An object of the present invention is to provide a heat-resistant
Improved fatigue resistance, fatigue resistance, impact resistance, and knot strength
Tire cord made of hexamethylene adipamide fiber
And a rubber reinforcing cord such as a belt or a belt .

[0006]

Means for Solving the Problems In order to achieve the above object, the present inventors have conducted intensive studies on the polymer composition and found that the fiber structure can be controlled by the balance between the acid and base concentrations determined by the acid-base titration method. I found that it was possible. More specifically, it has been found that by making the base concentration higher than the acid concentration, the thermal structure stability is high and a fiber structure having a high ratio of amorphous components can be obtained, and the present invention has been completed.

That is, according to the present invention, the relationship between the base concentration per 1 kg of polyamide determined by the acid-base titration method and the acid concentration per 1 kg of the polyamide determined by the acid-base titration method satisfies the following formula (1). and the feature that a change value of tanδmax by boiling water treatment consists of polyhexamethylene adipamide fibers is 0.015 or less
Rubber reinforcing cord . (Base concentration) − (acid concentration) ≧ 5 mmol (1) The polyamide of the present invention comprises adipic acid and hexamethylenediamine.
It is produced by polycondensation with an amine.

Further, the above-mentioned polyamides are usually added with additives such as inorganic phosphorus compounds such as phosphoric acid and sodium hypophosphite, organic phosphorus compounds such as phenylphosphonic acid and triphenylphosphite, and phosphorus-nitrogen compounds. Polymerization catalysts such as complex salts and phosphorus-nitrogen compounds, copper compounds such as copper acetate, copper bromide, copper iodide, and copper complex salts of 2-mercaptobenzimidazole, 2-mercaptobenzimidazole, tetrakis- [methylene-3- (3 5,5-di-tert-butyl-4-hydroxylphenyl) -propionate] -methane and the like, light stabilizers such as manganese lactate and manganese hypophosphite, matting agents such as titanium dioxide and kaolin, ethylene bisstearyl Lubricants such as amy, partially methylolated products, calcium stearate, plasticizers, and crystallization inhibitors can be included.

In the polyamide fiber of the present invention, the relation between the base concentration per 1 kg of polyamide determined by the acid-base titration method and the acid concentration per 1 kg of the polyamide determined by the acid-base titration method satisfies the formula (1). It is important. (Base concentration) − (acid concentration) ≧ 5 mmol (1) When the acid concentration becomes higher than the base concentration, the tan δmax value of the obtained polyamide fiber measured by a viscoelasticity measuring device decreases, and sufficient fatigue resistance, Impact resistance cannot be obtained. A preferable range of the relationship between the base concentration per 1 kg of the polyamide determined by the acid-base titration method and the acid concentration per 1 kg of the polyamide determined by the acid-base titration method is (base concentration) − (acid concentration) ≧ 10 mmol.

In the present invention, methods for increasing the base concentration of polyamide include basic inorganic compounds such as sodium hydroxide and potassium hydroxide, pyridine, 1,8-diazabicyclo (5,4,0) undecene-7 and the like. By adding a basic organic compound and an organic metal salt such as sodium acetate and sodium adipate directly to the polymer during the polymerization process, or by dissolving and adding to a finishing agent or the like after fiber formation.

In the case of a polyamide fiber comprising a condensate of a diamine such as polyhexamethylene adipamide and a dicarboxylic acid, it can be achieved by adding a large amount of the diamine component to the dicarboxylic acid component. At this time, since the vapor pressure of aliphatic diamines such as hexamethylenediamine is generally low and is scattered by the amidation reaction, it is possible to efficiently collect the scattered aliphatic diamines by once collecting and recycling them. Become.

It is also important that the polyamide fiber of the present invention has a tan δmax change value of 0.015 or less due to boiling water treatment. If it exceeds 0.015, a change in fiber structure during heat treatment or hot water treatment becomes large, and the physical properties are remarkably deteriorated. A preferred range of the change value of tan δmax by the boiling water treatment is 0.010 or less. Here, the boiling water treatment refers to a heat treatment at 130 ° C. for 30 minutes in an indefinite length state in a pressure vessel.

Further, since the polyamide fiber of the present invention is intended for use in the field of industrial materials, 7.0 g / d
It is preferable to have the above strength. Next, the method for measuring the acid / base concentration and the method for measuring tan δmax in the present invention will be described. The acid / base determination method for polyamides, particularly polyhexamethylene adipamide and polyεcaproamide, is shown below. (Quantitative determination method of base concentration) 6 g of a polymer is accurately weighed to three decimal places and dissolved in 50 cc of a 90% aqueous phenol solution. After complete dissolution, pH 3 with 0.05N aqueous hydrochloric acid
Titrate to. At this time, the amount of the 0.05 N hydrochloric acid aqueous solution added is recorded, and the base concentration per 1 kg of the polymer is calculated by the following formula.

[0014] A: Amount of 0.05N-hydrochloric acid aqueous solution required for titration (ml) F : Factor of 0.05N-hydrochloric acid aqueous solution B : Polymer weight (g) (Quantitative determination method of acid concentration) Weigh it and dissolve it in 50 cc of benzyl alcohol at 170 ° C. After complete dissolution, 1 liter of benzyl alcohol, 5 g of phenolphthalein, 0.5 g of copper acetate, 12 g of titanium dioxide
0.3 ml of the indicator prepared from the above is added. Thereafter, a 0.1N-NaOH ethylene glycol solution was added dropwise,
The end point is when the liquid color turns red. 0.1 at this time
Record the amount of the N-NaOH ethylene glycol solution added,
The acid concentration per 1 kg of the polymer is calculated by the following formula.

[0015] A: 0.1N-NaOH ethylene glycol solution (ml) required for titration F: Factor of 0.1N-NaOH ethylene glycol solution B: Polymer weight (g) In addition, tanδmax of the present invention is DDV- manufactured by Orientec. Use 01FP Reo Vibron, yarn length 2cm,
Single yarn 1 at 110 HZ under the condition of initial load 0.05 g / d
This is a value measured for a book. Tanδma said here
x is the average of the values measured for 10 single yarns.

Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples.

[0017]

【Example】

[0018]

Examples 1 and 2 and Comparative Examples 1 and 2 Table 1 shows the difference between the base concentration per 1 kg of polyamide determined by the acid-base titration method and the acid concentration per 1 kg of the polyamide determined by the acid-base titration method. And 31 mmol, 9 mmol in Table 2.
1, -8 mmol, and -34 mmol by controlling the component ratio of hexamethylenediamine and adipic acid, and using a conventional polymerization method, 90% formic acid relative viscosity (hereinafter referred to as V).
(Referred to as R) 80 polyhexamethylene adipamide polymer was obtained. The relative viscosity of 90% formic acid here is 90% formic acid.
This is the relative viscosity at 25 ° C. of a solution dissolved in formic acid to a polymer concentration of 8.4% by weight.

The above polymer was prepared by the method described in JP-A-59-199812.
The fiber was spun and stretched by a conventional method as disclosed in Japanese Patent Application Laid-Open No. H10-163, and a polyhexamethylene adipamide fiber was obtained. Table 1 shows the fiber properties at that time. The fiber properties referred to herein are measured at a descent speed of 30 cm / min and a chart speed of 60 cm / min on a 25 cm raw yarn sample to which 80 turns / m of twist have been applied, using an Autograph S-100C manufactured by Shimadzu Corporation. Value. The knot strength herein refers to the use of a Tensilon made by Toyo Baldwin Co., Ltd. to attach a sample consisting of a single fiber having a loop length of 50 mm to a hook sandwiched between the tensilon upper and lower chucks, a gauge length of 50 mm, and an elongation speed of 1 mm.
It is a value measured at 00% / min and a recording speed of 500 mm / min. The knot strength shown in Table 1 is an average value measured for 10 filaments.

The higher the base concentration per kg of the polymer, the higher the toughness of the obtained polyhexamethylene adipamide fiber and the higher the knot strength.

[0021]

[Table 1]

Next, the obtained yarn was subjected to a fatigue resistance test. Each of the raw yarns was twisted 39 times / 10 cm, and then each of the two twisted yarns was twisted 39 times / 10 cm to obtain a raw cord. The raw cord was treated with a resorcinol-formaldehyde-latex liquid using a three-oven hot stretch apparatus under the following conditions. This treated cord was vulcanized under vulcanization conditions of 155 ° C. × 40 minutes, and a fatigue resistance test was performed according to a Goodyear tube fatigue test. The good-ear tube fatigue test mentioned here is as follows.

Method according to JISL-10173.2.2.2.1A Tube shape Inner diameter 12.5mm Outer diameter 26mm Length 230mm Bending angle 90 ° Internal pressure 3.5kgf / cm ² Number of rotations 850rpm Table 2 shows the results of the Goodyear method tube fatigue test. Is shown.

As the base concentration per kg of the polymer is increased, the fatigue resistance is improved.

[0025]

[Table 2]

[0026]

Code polyhexamethylene adipamide fibers used in the present invention exhibits heat resistance, fatigue resistance, impact resistance, and since knot strength is significantly improved, tire cord, such as a belt rubber When used as a reinforcing cord for industrial materials, the product has excellent durability.

Claims (1)

(57) [Claims] 1. The relation between the base concentration per 1 kg of polyamide determined by acid-base titration and the acid concentration per 1 kg of polyamide determined by acid-base titration satisfies the following formula (1), and Tanδma by processing
A rubber reinforcing core comprising a polyhexamethylene adipamide fiber having a change value of x of 0.015 or less.
Mode . (Base concentration) − (acid concentration) ≧ 5 mmol (1)