JPS63249717A - Polyester yarn and production thereof - Google Patents

Abstract

PURPOSE:To obtain the titled yarn having high strength and heat resistance in rubber, by copolymerizing a main component comprising ethylene terephthalate with a specific unit to give a polyester, drawing and heat-treating undrawn yarn of the polyester under a specific condition. CONSTITUTION:First, a main repeating unit comprising ethylene terephthalate is copolymerized with 0.1-2mol.% based on sum of repeating units of a repeating unit shown by the formula to give a polyester, which is usually subjected to melt spinning to give undrawn yarn. The undrawn yarn of polyester is drawn under a condition to satisfy the formula 0.8<=DR/DRmax<=0.9 (DR is draw ratio; DRmax is breaking draw ratio) and heat-treated at 200-230 deg.C heat-treatment temperature to give the aimed yarn which has >=30% crystallinity and <20wt.% percentage loss of weight when the yarn is treated in 60wt.% aqueous solution of ethylamine at 30 deg.C for 20hr.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a polyester fiber and a method for producing the same, and more particularly to a polyester fiber with high strength and excellent heat resistance in rubber, and a method for producing the same.

(Prior Art) Due to its excellent mechanical and thermal properties, polyester fibers are used not only in the clothing field, but also in tire cords, conveyor belts, and ■-Bell 1~. It is also widely used as an industrial fiber for hoses, sewing threads, etc.

In recent years, the specific gravity of such polyester fibers as industrial fibers has become higher and higher than that for clothing, and as a result, the physical properties required of industrial fibers, especially polyester fibers as fibers for reinforcing rubber structures, have become even more severe. ing. Under these circumstances, many improvements have been made with the aim of producing polyester fibers with high strength and high heat resistance, but they are still insufficient.

For example, in order to increase the strength of polyester fibers, it is useful to increase the degree of orientation of the amorphous part in the fiber structure. known (for example, Tokuko Sho 5)
3-1367). However, although the fibers obtained by this method can have some degree of strength, they are still not strong enough and have poor heat resistance in rubber, that is, hydrolysis resistance under high humidity conditions. It is inferior in terms of amine resistance, and improvements are required.

In order to improve the heat resistance in such rubber, Japanese Patent Application Laid-Open No. 56-910
No. 09 proposes a fiber for reinforcing rubber structures made of a polyester with a small amount of terminal carboxyl groups, which is obtained by adding a minimum amount of a bisoxazoline compound to a polyester.

It is true that by adding a bisoxazoline compound, it is possible to increase the degree of polymerization while decreasing the terminal carboxyl groups of polyester, so fibers made of such polyester have higher strength and improved heat resistance than conventional polyester fibers. There is.

However, although such polyester fibers have excellent heat resistance, it has been found that they lack strength.

(Object of the Invention) An object of the present invention is to provide a polyester fiber having high strength and excellent heat resistance in rubber, and a method for producing the same.

(Structure) As a result of studies to achieve the above object, the present inventor found that the acid component substantially consists of a terephthalic component, and the glycol component consists of an ethylene glycol component and bis(hydroxyethoxy)benzene [10cH2cH20-gu)-0CHzCHzOH.
(Hereinafter, sometimes referred to as B HE B)] It has been discovered that high strength and heat resistance in rubber can be improved by using polyester, and the present invention has been achieved.

That is, in the present invention, the main repeating unit consists of ethylene terephthalate, and the following [[
A polyester fiber in which 0.1 to 2 mol% of repeating units represented by the formula I] are copolymerized, the fiber has a crystallinity of 30% or more, and is A polyester fiber characterized by a weight loss rate of less than 20% by weight when treated for a period of time, the main repeating unit being composed of ethylene terephthalate,
In addition, an undrawn polyester yarn in which 0.1 to 2 mol% of repeating units represented by the following formula [I] are copolymerized with respect to all repeating units, satisfying the following formulas [I[] to [1]] This is a method for producing polyester fiber, which is characterized by stretching and heat treatment.

Su... ['I] R 0,80≦□≦0.90...III]
□ Rmax 200°C≦Heat treatment temperature≦230″C...[III] The polyester used in the present invention is a polyester in which the acid component consists essentially of a terephthalic acid component, and the polyester consists of a glycol component or an ethylene glycol component and a BHEB component. Cover with the main object.

Such polyesters can be produced by any method. For example, terephthalic acid and ethylene glycol and B
Either avoid a direct esterification reaction with HEB, or carry out a transesterification reaction between a low-carbon alkyl ester of terephthalic acid, such as dimethyl terephthalate, and the glycol. It is easily produced by forming a low polymer and then heating the product under reduced pressure to carry out a single condensation reaction until the desired degree of 3 Ω is reached.

The degree of polymerization of the obtained polyester is preferably 0.80 or more, particularly 0.83 to 0.95 in terms of intrinsic viscosity. Note that the intrinsic viscosity was determined by measurement in an O-chlorophenol solution at 35°C.

The content of the Bl-IEB component, which forms part of the glycol component of the polyester thus obtained, must be in the range of 0.1 to 2 mol% based on the total repeating units constituting the polyester.

Here, the B + -I E B component is less than 0.1 mol%,
Alternatively, if the polyester content exceeds 2 mol %, it is impossible to obtain polyester fibers that are highly strong and have good heat resistance in rubber.

In the present invention, 0.0
It is preferable to add 5 to 0.2% of a bisoxazoline compound in the handing process or the spinning process to improve the degree of polymerization while reducing the amount of terminal lubogyl groups.

The polyester fiber of the present invention must be a fiber made of the above-mentioned polyester, and must have a crystallinity of 80% or more and a loss rate (hereinafter referred to as amine loss rate) when treated in a 60% ethylamine aqueous solution at 30°C for 20 hours. It is necessary that the weight loss rate (sometimes referred to as weight loss rate) is 20% or less. Polyesters and fibers with a crystallinity of less than 80% or an amine weight loss rate of more than 20% will not have high strength and will not improve the heat resistance in rubber.

In order to make the polyester fiber of the present invention described above, the B HE B component is 0.1 with respect to all repeating units.
It is obtained by stretching and heat-treating an undrawn yarn obtained by melt-spinning a polyester copolymerized with ~2 mol % while satisfying the following formula [n]~1fll.

R 0,80≦□≦0.90 ...[II]D
Rmax Here, DR/D Rma
If x is less than 0.80, the amine loss rate of the drawn yarn exceeds 20%, which deteriorates the heat resistance in the rubber. On the other hand, if DR/DRmax exceeds 0.90, , Single fiber breakage occurs frequently during the drawing process.

Such stretching is preferably carried out while heating the undrawn yarn to a temperature higher than its glass transition temperature, particularly higher than 80'C.

Furthermore, if the heat treatment temperature is lower than 200'C, the crystallinity of the fibers will be lower than 80%, resulting in a decrease in strength. On the other hand, if the heat treatment temperature exceeds 230°C, yarn breakage occurs frequently during the heat treatment.

Such stretching and heat treatment are performed by placing a heater of 9Ω in play 1 between a supply roller that is heated to a temperature higher than the glass transition temperature of the undrawn yarn and a take-up roller that rotates at a higher speed than the supply roller. The method is preferred.

In addition, in the polyester used in the present invention, a part of the terephthalic acid component may be replaced with another difunctional carboxylic acid component. Examples of such carboxylic acids include isophthalic acid, phthalic acid, naphthalene dicarboxylic acid, and diphenyl dicarboxylic acid.

Difunctional aromatic carboxylic acid such as diphenoxyethanedicarboxylic acid, β-Axyethoxybenzoic acid, D-oxybenzoic acid, p-oxybenzoic acid, difunctional aliphatic carboxylic acid such as sebacic acid, adipic acid, and oxalic acid. Examples include difunctional alicyclic carbonic acids such as 1,1,4-cyclohexanedicarboxylic acid.

Furthermore, part of the ethylene glycol component among the glycol components may be replaced with other glycol components, such as cyclohexane-1,
Examples include aliphatic, alicyclic, and aromatic diol compounds such as 4-dimetatool, neopentyl glycol, bisphenol A, and bisphenol S.

Furthermore, for example, modifiers, stabilizers, etc. may be optionally used in such polyesters as necessary.

(Function) The polyester fiber of the present invention has a high degree of crystallinity and a low amine weight loss rate, so it has high strength and good heat resistance in rubber.

(Effects of the Invention) The polyester fiber of the present invention can be preferably used as a fiber for reinforcing rubber structures, which requires high strength and heat resistance in rubber.

Example 97 parts of dimethyl terephthalate, 6 parts of ethylene glycol
9 parts of BHEB as shown in Table 1, 0.034 parts of calcium acetate monohydrate, and 0.025 parts of antimony trioxide were placed in an autoclave, and transesterification was carried out at 180 to 230'C while slowly passing nitrogen through. After removing the resulting methanol, 0.05 part of a 50% aqueous solution of H3P O4 was added, the heating temperature was raised to 280°C, and the pressure was gradually reduced. It took about 1 hour to reduce the pressure in the reaction system. was set to 0.2 mmHg and the polymerization reaction was continued for 1 hour and 50 minutes, resulting in an intrinsic viscosity of 0.80. 128 terminal carboxyl groups! /
A 106 gram polymer was obtained.

100 parts of this polymer chip was triblended with 0.15 wt% of 2,2-bis(2-oxazoline) (CE), and then melted and transported at about 300'C to form a pore size of 0.6 mm.
After being discharged from a spinneret having 250 holes, an oil agent was applied with an oiling roller and the material was wound up at a take-up speed of 600 m/min.

This undrawn fiber is supplied to a roll heated to 85°C,
The magnification shown in Table 1 (DR/DRma
After stretching in step x), it was brought into contact with a plate heater heated to the temperature shown in Table 1 and subjected to tension heat treatment. Table 1 also shows the crystallinity of the drawn yarn, the weight loss rate after treatment with a 60% ethylamine aqueous solution at 30° C. for 20 hours, and the strength and elongation.

Next, these drawn yarns were given 7 twists of 490 turns/m, and then two of these were combined and given an S twist of 490 turns/m to give 1000 twists.
dex Two raw cords were used. This raw cord was immersed in an adhesive (RFL liquid) and subjected to tension heat treatment at 245° C. for 2 minutes. This treated cord was embedded in rubber and vulcanized, and its heat resistance and strength were measured. The results are also listed in Table 1.

Note that the characteristic values of the treated cords were measured by the following method.

(1) Load-stretching curve is JIS L 1017-196
3 (5, 4).

(2) For heat resistance and strength, the raw cord was immersed in RFL adhesive solution and heat treated at 245° C. for 2 minutes under tension. Embed this processing cord in a vulcanization mold at 170°C and 50kg/cm2 pressure.
After accelerated vulcanization for 120 minutes, the treated cord was taken out and its strength was measured.

As is clear from Table 1, the polyester fibers within the scope of the present invention have high strength and also have excellent heat resistance strength retention in rubber.

Claims (1)

[Scope of Claims] (1) A polyester whose main repeating unit consists of ethylene terephthalate, and in which 0.1 to 2 mol% of repeating units represented by the following formula [I] are copolymerized with respect to all repeating units. A fiber, the crystallinity of the fiber is 3.
A polyester fiber having a weight loss rate of 0% or more and less than 20% by weight when treated for 20 hours in a 60% ethylamine aqueous solution at 30°C. ▲There are mathematical formulas, chemical formulas, tables, etc.▼... [I] (2) The main repeating unit consists of ethylene terephthalate, and the repeating unit expressed by the following [I] formula is 0.1 to all repeating units. A method for producing polyester fibers, which comprises stretching and heat-treating an undrawn polyester yarn copolymerized with ~2 mol% while satisfying the following formulas [II] to [III]. ▲There are mathematical formulas, chemical formulas, tables, etc.▼...[I] 0.80≦DR/DRmax≦0.90...[II]
DR; Stretching ratio DRmax; Stretching ratio at break] 200°C≦Heat treatment temperature≦230°C... [III]