JPS6141320A - Polyester fiber - Google Patents

Abstract

PURPOSE:To provide the titled fiber consisting of a polyester containing ethylene terephthalate as the recurring unit and having specific physical properties, high strength, low shrinkage, and excellent fatigue resistance and drawability, and suitable as an industrial material. CONSTITUTION:For example, a polyester containing ethylene terephthalate as the recurring unit and having an intrinsic viscosity of 0.95-1.5 is spun under melting, quenched, solidified by cooling, coated with a lubricant, taken up at a high speed, and drawn to obtain the objective fiber having a half-value width of the principal component in the temperautre dispersion of mechanical loss modulus of <=45 deg.C, the peak temperature of the principal dispersion of <=125 deg.C, the crystal size of >=80Angstrom , and a dry heat shrinkage of 2.5-4% at 210 deg.C, and consisting of a polyester containing ethylene terephthalate as the recurring unit and having an intrinsic viscosity of >=0.9.

Description

DETAILED DESCRIPTION OF THE INVENTION a. Field of Industrial Application The present invention relates to a polyester fiber for use in the delivery room that has high strength, low shrinkage, good fatigue resistance, and good stretchability.

b. Prior Art Polyester fibers have various excellent properties, and are widely used not only for clothing but also for industrial purposes. Polyester fibers have particularly high strength and excellent dimensional stability.
They are useful in industrial applications and are increasingly being used not only in tire applications but also in property applications, but recently high performance has been required for both. For example, in conveyor belt and rubber hose applications, dimensional stability during molding, lower shrinkage, durability under harsh usage conditions, and fatigue resistance are required.

Currently, in this field, rayon fibers and vinylon fibers, which have a long history, are commonly used, and polyester fibers are also beginning to be used. However, although polyester fibers have high strength, they are insufficient in low shrinkage, durability, and fatigue resistance. If these properties can be improved from the viewpoint of strength and strength, polyester fibers with excellent cost and performance will become increasingly popular as materials for properties.

In order to achieve the high strength required for industrial fibers,
An example is Japanese Patent Publication No. 41-7892.

A method is known in which a high degree of polymerization polyester is used as disclosed in Japanese Patent Publication No. 53-1367, molecular orientation is suppressed in the spinning stage, and the stretching ratio is increased as much as possible in the stretching stage.

However, according to this method, since the degree of orientation of the amorphous molecular chains is high, high strength can be obtained, but on the other hand, the shrinkage rate also increases. On the other hand, in order to reduce the shrinkage rate, a method is known in which a low degree of polymerization polyester is used, for example as disclosed in JP-A-53-58028. However, with this method, it is difficult to obtain products with high strength and toughness. Furthermore, in order to reduce the shrinkage rate,
As disclosed in Japanese Patent No. 51524, a method is known in which, after multi-stage stretching, low tension crab heat treatment is performed at high temperature.

However, like the above two methods, this method also provides only a product with low fatigue resistance.

In order to achieve low shrinkage and fatigue resistance, for example, Japanese Patent Application Laid-open Nos. 53-58031 and 53-58032 disclose that the degree of molecular orientation of the drawn yarn is lowered and the work loss is reduced to improve resistance. Polynisdel fibers and methods for producing the same have been proposed for the purpose of improving fatigue properties. This method involves rapid cooling under a spinneret in a gas atmosphere of 10 to 60°C, but the degree of elongation is extremely small because the yarn is stretched to the point of cutting to achieve high strength. The disadvantage is that thread breakage occurs frequently, making stable production difficult.

Means for Solving the Problem The present inventor has conducted intensive studies to provide a polyester fiber for industrial use that has high strength, low shrinkage, and fatigue resistance, and has good drawability. , high strength and low shrinkage only when it has a certain degree of polymerization and the amorphous part and crystal part are in a certain state.

A heading that has good fatigue resistance and good stretchability,
The present invention has been achieved.

That is, the present invention is made of polyester whose main repeating units are ethylene and terephthalate and whose intrinsic viscosity is 0.9 or more.
The half value width of the main component that appears in the temperature dispersion of the mechanical loss modulus is 45°C or less.

The peak temperature of the main dispersion is 125°C or less, the crystal size is 80A or more, and the dry heat shrinkage rate at 210°C is 2.5 a! This relates to polyester fibers that are higher than b and 4% or less.

Poly-q-1tt constituting the polyester fiber of the present invention
, molecule, with 9 ethylene terephthalate repeating units in the chain
It is a polyester containing 0 mole or more, preferably 95 or more mole. Polyethylene terephthalate is suitable as such polynisdel, but it may contain other copolymer components in a proportion of less than 10 molti, preferably less than 5 molti. Examples of such copolymerization components include isophthalic acid, naphthalene dicarboxylic acid, adipic acid,
Examples include oxybenzoic acid, diethylene glycol, glopylene glycol, trimellitic acid, and pentaerythritol. These polynisdels may also contain additives such as stabilizers 1 and colorants.

The polynisder fiber of the present invention needs to have an intrinsic viscosity of 0.90 or more as determined from a 25CO-PO phenol solution. If the intrinsic viscosity is less than 0.90, a polyester fiber with high strength while maintaining low shrinkage and fatigue resistance cannot be obtained. The intrinsic viscosity is preferably from 1.9 to 1.3.

In the polyester fiber of the present invention, it is necessary that the amorphous portion simultaneously satisfies the following conditions 1 to 2 from the temperature dispersion behavior of the mechanical loss modulus.

■ The half value width of the main component appearing in the temperature dispersion of the mechanical loss modulus is 45°C or less, ■ The peak temperature of the main dispersion is 125°C or less, where the mechanical loss modulus is measured using a spectrometer Y manufactured by Wakagi Seisakusho.
0.251 on a 3 cm long sample using the ES-F model.
Measurements were made under the conditions of a 1/da quiet load, an amplitude of 0.17%, a frequency of 10H2, and a temperature increase rate of 1.6° C./min.

The half-width of the main component is the temperature at the peak showing 1/2 of the peak value of the main component. This half-width indicates the distribution of the degree of amorphous orientation in the amorphous region, and it can be said that the root distribution with a small half-width is small. If the half width exceeds 45°C, stress concentration occurs on specific molecular chains in the amorphous region when stress is applied to the fibers, making the molecular chains easy to break, resulting in poor fatigue resistance and is therefore unsuitable.

Furthermore, the peak temperature of the main fraction indicates the degree of molecular orientation in the amorphous region, and it can be said that the lower the peak temperature, the lower the degree of orientation. When the peak temperature exceeds 125°C, the degree of orientation is high;
Although it has high strength, it does not simultaneously satisfy low shrinkage and fatigue resistance.

The polyester fiber of the present invention has a long molecular chain length expressed by the intrinsic viscosity, a low distribution of the amorphous orientation degree, even if the degree of amorphous orientation is not so high, and has a desired balance with the crystalline portion described below. It combines strength, excellent shrinkability, and fatigue resistance.

In the polynisder fiber of the present invention, it is necessary that the crystal size is 80A or more, which indicates a crystalline portion.

Here, the crystal size was calculated using the Scherrer equation from the half-width of the (010) (100) intensity distribution curve of equatorial line scanning based on the conventional X-ray wide-angle diffraction method Kik. If the crystal size is less than 80x, when the polynisder fiber is subjected to heat treatment in a post-processing step after knitting and weaving, for example, strength deterioration tends to occur, making it unsuitable.

As mentioned above, the polyester fiber of the present invention can achieve high strength even in post-processing steps only when its amorphous structure and crystalline structure simultaneously satisfy a specific range.

It has low shrinkage and good fatigue resistance.

The polyester fiber of the present invention has a strength of 6. OJi'/do
It exhibits high strength and elongation of 10 inches or more, preferably 20% or more, which is sufficient for industrial uses, and shows high toughness and high durability.
The dry heat shrinkage rate at 0°C is higher than 2.5 tlb and is less than 4, which is an extremely low shrinkage rate. In addition, the dry heat shrinkage rate at 210°C is JIS L 1017-1963 (5, 12)
Calculated according to the method described in K.

The polyester fiber of the present invention can be obtained, for example, by the following method.

Polyester containing ethylene terephthalate as the main repeating unit and having an intrinsic viscosity of 0.95 to 1.5 or an intrinsic viscosity of 0
．． 7 to 0.9 polyester is reacted with a degree of polymerization accelerator, melted and transported by a conventional method, and discharged from a spinneret into yarn so that the fineness after drawing is 1 to 20 de and the total denier is 500 to 2000 de, Immediately after discharge, the material is rapidly cooled, kept at a temperature below the melting point to the temperature at which crystallization begins, or exposed to a heated atmosphere at a temperature above the melting point for a certain period of time for delayed cooling.

Thereafter, it is cooled and solidified in a filamentous manner, and it is useful to cool and solidify it under the following conditions.Then, after being cooled and solidified as described above, the oil agent is applied and then taken off at a speed of 3000 m/min or more.

For example, oil application is done by one-way oilin p-ra system.

Any method is possible, such as a one-way spray method.

Further, as the oil agent, any textile oil agent can be applied depending on the necessity. At this time, in fields where adhesion with rubber is important as a fiber application, it is useful to apply a surface treatment agent to impart adhesion.

By selecting the above conditions as needed, the intrinsic viscosity becomes 0.
．． A crystalline undrawn fiber having a cutting elongation of 90 or more and a cutting elongation of 150% or less, with crystallinity XX and birefringence △n of XX
= 2.4X10" is obtained.

In the present invention, the undrawn fibers having the above-mentioned characteristics, which are drawn at a molecular speed of more than aoooom/min, may be drawn continuously following spinning, or may be drawn in a subsequent process after being wound once. . When the spinning is followed by continuous drawing, it can be carried out in accordance with the method proposed earlier in Japanese Patent Application No. 88927/1983. Further, in the case where the fiber is once rolled up and then stretched at 0.degree. C. after spinning, it can be carried out in accordance with the method disclosed in Japanese Patent Application No. 57-189094 previously proposed. The latter stretching method is preferred in terms of reducing stretching strain during stretching and heat treatment strain. That is, the undrawn fibers were heated at Tli+15 to T, 9+50°C (
Here, T9 is the glass transition temperature of the fiber), and after preheating for at least 0°5 seconds, the first stage drawing is performed at a ratio of 75% or less of the total drawing ratio, and the birefringence is 1.2 to 3. The birefringence is 3 times higher. Next, the single-stage drawn yarn is further subjected to multi-stage drawing heat treatment. At this time, in industrial applications where the drawn fibers are used as they are without being coded, the melting temperature of the multi-stage drawing heat treatment -
0.4 to 1.5 in the range of 50℃ to melting temperature -110℃
It is preferable to carry out a relaxation heat treatment of 10 to 20% while holding for seconds.

The polyester fibers obtained in this manner are used for industrial purposes either after being knitted or woven as they are or after being heat-treated. At this time, the excellent fiber properties are expressed as they are and are extremely effective. It can also be applied to rubber structures by conventional methods, such as forming cords, applying adhesive, and heat treating. Note that the term "rubber structure" refers to a structure made of natural rubber or synthetic rubber, such as an EVA hose, a belt, or a conveyor belt.

d Example The present invention will be explained in more detail below with reference to Examples.

Note that all parts in the examples indicate parts by weight.

Example 7 parts of dimethyl terephthalate, 6 parts of ethylene glycol
After charging 9 parts of calcium acetate, 0.034 parts of calcium acetate hydrate, and 0.025 parts of antimony dioxide into an autoclave, and removing methanol produced as a result of transesterification at 180 to 230°C while slowly passing nitrogen, P
Add 0.05 part of a 50% aqueous solution of O4 and raise the heating temperature to 28
While raising the temperature to 0°C, the pressure was gradually reduced, and it took about 1 hour to reduce the pressure of the reaction system to 0.2°C.
The partial polymerization reaction was continued to obtain a polymer having an intrinsic viscosity of 0.80 and a terminal carboxyl group weight of 28 equivalents/10' Durham polymer.

100 parts of this polymer chip was triblended with 2,2'-bis(2-oxazoline) CE in the amount shown in Table 1, and then melted and transported at about 300'C, with a pore diameter of 0.6 m++ and a pore number of 2.
After the yarn is discharged from a spinneret having 50 spinnerets, the discharged yarn is maintained under the cooling conditions listed in Table 1, and then 25°C cooling air is applied to the yarn for 30 minutes.
After cooling and solidifying while spraying 4.0 Nm"/min over a distance of 0 m, the oil was applied with an oiling roller, and then the first
It was rolled up at the take-up speed listed in the table. The properties of the obtained undrawn fibers are shown in Table 1.

This undrawn fiber is supplied to a roll heated to 85°C,
1st at the magnification (DR□) listed in Table 1 between the take-up roll
After stage stretching, a second stage stretching was carried out at the magnification (DR,) shown in the table through a gas bath heated to 325°C. Then, using a heating p-ra at 130°C and a gas bath at 330°C, the magnification is O as specified in the table.
Relaxation heat treatment was performed at Rm. The performance of the obtained drawn yarn is also listed in Table 1.

Note that the tube life in the table indicates fatigue resistance, and was measured using a code prepared as follows.

The drawn yarn was given two twists of 490 turns/m, and then the two were combined and given an S twist of 490 turns/m to form two 1000 deX raw cords. 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 to measure the life of the tube.

The measurement was performed in accordance with JIS L1017-1963.1.3.2.
IA legal compliance. However, the bending angle was 90''.

Procedure correction port September 1981

Claims (2)

[Claims] (1) Made of polyester whose main repeating unit is ethylene terephthalate and whose intrinsic viscosity is 0.9 or more, and whose half value width of the main component, which appears in the temperature dispersion of mechanical loss modulus, is 45°C.
Hereinafter, the polyester fiber has a peak temperature of the main dispersion of 125°C or less, a crystal size of 80 Å or more, and a dry heat shrinkage rate at 210°C of more than 2.5% and 4% or less. (2) The polyester fiber according to claim (1), which has a cutting strength of 6.0 g/de or more.