JPH03223383A - Melt viscosity-reducing agent for polyester resin, and polyester fiber - Google Patents

Abstract

PURPOSE:To obtain a melt viscosity-reducing agent which can reduce the melt viscosity of polyester resin without decreasing the degree of polymerization, by using as its constituent a specified compound obtained by subjecting a dicarboxylic acid diamide compound to condensation through dehydration. CONSTITUTION:A melt viscosity-reducing agent comprising a compound of the formula (wherein R is 12-22C linear-chain alkyl). If the number of carbon atoms of R of the formula compound is below 12, the molecular weight will be so low that the compound may sometimes boil at its melting temperature to cause bubbling; if above 22, the compatibility with resin will be poor so that uniform mixing with resin will be difficult. The compound of the formula can be easily obtained by reacting 1mol of pyromellitic anhydride with 2mol of a 12-22C amine to give a dicarboxylic acid diamide compound and subjecting this compound to condensation through dehydration. High tenacity polyester fiber can be obtained from a polyester resin composition having the melt viscosity-reducing agent incorporated therein.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a melt viscosity reducing agent for polyester resins and a polyester fiber that is easy to spin and has a good texture.

[Conventional technology]

Conventionally, polyester resins have been widely used as synthetic fibers, but it is believed that increasing the degree of polymerization of the polymer is sufficient to increase the strength of synthetic fibers. However, increasing the degree of polymerization of the polymer naturally increases the melt viscosity, resulting in poor processability and reduced productivity. One way to lower the melt viscosity is to raise the melting temperature, but since this accelerates the decomposition of the resin, it is difficult to achieve the goal of lowering the degree of polymerization and obtaining fibers with a high degree of polymerization. do not have.

Polyester filaments with a high degree of polymerization are used in the field of high-strength industrial yarns, but there is a need to further increase the strength, and to achieve this, it is necessary to lower the melt viscosity of the resin. Furthermore, in the case of staple threads, lowering the melt viscosity of the polymer leads to an improvement in the extrusion ability from the nozzle or a reduction in the power, which contributes to increasing productivity.

Even in the field of high-speed spinning, which has recently been put into practical use, it is effective to lower the melt viscosity of the resin in order to increase the discharge rate.

In order to solve these problems, adding a lubricant was considered, but adding ethylene bisstearamide, stearic acid, stearyl alcohol, etc. to the resin lowers the melt viscosity, but at the same time the degree of polymerization of the resin also decreases. I know what to do.

On the other hand, polyester fibers inherently have a poor texture and a squeaky feel. To solve this problem, fine denier processing, alkaline weight reduction processing, softening agent processing, etc. are being carried out.

Regarding fine denier, these conventional techniques are described in "Dyeing Industry" (written by Shigenobu Kobayashi), Vol. 38, pp. 288-299.
For alkali weight loss processing, please refer to “J, Soc, Dye
rsColorists J (1, E, Haden) vol. 78, p. 9, 1962, 'The Texti
le Mfr, J (written by B, C, M, Dorset)
293 (July 1963 issue), and US Pat. No. 3,377,249 describes fabric softener processing.

[Problem to be solved by the invention]

The problem to be solved by the present invention is to find a melt viscosity reducing agent that can reduce the melt viscosity of a polyester resin without essentially reducing the degree of polymerization, and to use this agent to provide fibers that are easy to spin, have good texture, and are strong. The objective is to obtain superior polyester fibers.

[Means to solve the problem]

The present inventors have discovered that a specific compound exhibits an excellent effect on the above-mentioned problems, and have completed the present invention.

That is, the present invention provides a melt viscosity reducing agent for polyester resin comprising a compound represented by the general formula (1) (wherein R represents a linear alkyl group having 12 to 22 carbon atoms), and a raw material polyester resin. The present invention provides a polyester fiber obtained by melt-spinning a polyester resin composition prepared by adding and mixing the above melt viscosity reducing agent for polyester resin.

In the compound of formula (1) according to the present invention, the number of carbon atoms in R can be arbitrarily selected within the above range.

If the number of carbon atoms in R is less than 12, the molecular weight is too low and it may boil at the melting temperature and form bubbles, and if it exceeds 22, the compatibility with the resin deteriorates, making it difficult to mix uniformly with the resin.

The compound represented by the general formula (1) according to the present invention is prepared by reacting 1 mole of pyromellitic anhydride with 2 moles of an amine having 12 to 22 carbon atoms to obtain a dicarboxylic acid diamide compound, and then dehydrating the compound. easily obtained.

The melt viscosity reducing agent of the present invention is uniformly added to and mixed with the polyester resin, and exhibits excellent heat resistance, with almost no smoke generation or coloring even when exposed to high temperatures during melt spinning.

High-strength polyester fibers can be obtained from the polyester resin composition to which the melt viscosity reducing agent for polyester resins of the present invention is added.

The use of high molecular weight polymer chips is a prerequisite for producing high-strength fibers. These polymer chips are normally melted at 280 to 300"C during spinning, but due to the entanglement of polymer chains, the higher the molecular weight of the polymer, the higher the melt viscosity, resulting in an increase in discharge pressure and poor stringability. However, the presence of the melt viscosity reducing agent of the present invention reduces spinning pressure and yarn tension, making spinning smoother.

The yarn discharged from the nozzle is once cooled and solidified.

When polyester resin is used for injection molding, promotion of crystallization during cooling is preferable for the purpose of improving moldability, but crystallization during cooling is not preferable when melt spinning polyethylene terephthalate resin or the like. The melt viscosity reducing agent of the present invention does not cause crystallization of the resin during the cooling process from the spinning nozzle. The undrawn fibers that have been cooled and taken off are oriented and crystallized in the subsequent drawing and heat treatment steps to become highly strong fibers.

In order for the melt viscosity reducing agent of the present invention to exhibit its intended performance, 100 parts of the raw polyester resin (by weight,
0.1 to 10 parts, preferably 0.1 to 10 parts, preferably 0.
It is necessary to add 5 to 5 parts. If the amount is less than 0.1 part, hardly any effect can be expected, and if it is more than 10 parts, the physical properties of the resin may be adversely affected.

The melt viscosity reducing agent of the present invention may be added to the raw polyester resin during resin production or at an appropriate step after production, or may be mixed and added to resin pellets or molten resin during spinning. .

The high-strength polyester fiber of the present invention can be obtained by uniformly mixing the raw material polyester resin and the melt viscosity reducing agent of the present invention, spinning the mixture in a molten state, and subjecting the fiber to stretching and heat treatment after cooling. After cooling, the spun yarn may be wound up as an undrawn yarn, then preheated and stretched, and then heat treated under tension. Alternatively, the spun yarn may be taken off with a take-up roller without being wound up, and then placed on a heated roller. Stretching and heat treatment may be performed.

Stretching and heat treatment can be carried out in the same manner as for ordinary polyester fibers. The preferred preheating temperature during stretching is 6
The preferred temperature for heat treatment is 0-100°C150-25
It is 0°C. The stretching ratio to obtain high strength fibers is 4.
It is desirable to double or more.

The polyester resin according to the present invention preferably has polyethylene terephthalate as a main repeating unit, and other components such as polyethylene glycol, POE (2
) Partial copolymerization of bisphenol A1, sulfonated sodium isophthalate, 1, 4-butanediol, etc. may also be used.

〔Example〕

The present invention will be specifically explained below with reference to Examples, but the present invention is not limited to these Examples.

Example 1 The compounds shown in Table 1 were added to polyethylene terephthalate resin, then melt-mixed in an extruder, and the resulting strands were cooled with water and cut to give samples. The melt flow index of this resin composition was determined as follows: Temperature: 275°C, Load: 216°C
It was measured as the amount of molten resin extruded in 10 minutes from an orifice with a diameter of 2.095 mm and a length of 81 at 0 g. It can be said that the larger the melt flow index, the lower the melt viscosity. The sample after melt flow index measurement was dissolved in a phenol/tetrachloroethane (60/40, weight ratio) solution, and the intrinsic viscosity [η] at 25°C was determined.
was measured. If [η] is the same as that without additives, it can be said that there is essentially no decrease in the degree of resin polymerization.

The results are shown in Table 1.

Table ■Results> The compound of the present invention essentially makes it possible to reduce the melt viscosity without reducing the intrinsic viscosity, and is effective in reducing the resin spinning pressure and increasing the spinning speed.Example 2 Intrinsic viscosity After adding distearyl bilomeri nodoic acid diimide represented by the following formula to 100 parts by weight of a polyester resin of 1.0, the mixture was melt-mixed in an extruder, and the resulting strands were cooled with water and cut into chips. The intrinsic viscosity of this chip was 0.85.

This chip is put into an extruder type melt spinning machine,
The temperature of the spinning section was set to 290°C, and the spun yarn was discharged from a spinning nozzle with a diameter of 0.5 mm at a rate of 2 g/min, and was wound up at a rate of 1000 m/min at a position 2.5 m directly below the nozzle. The wound undrawn yarn was stretched in an oil bath at 80° C. while changing the draw ratio, and then heat-treated at 170° C. for 30 minutes under constant length conditions.

The pressure at the nozzle during spinning was 50 kgf/cd, and the intrinsic viscosity of the undrawn yarn was 0.70.

Table 2 shows the frequency of yarn breakage and yarn strength during stretching and heat treatment when the stretching ratio was changed.

Table ○: The undrawn yarn with no yarn breakage and ΔD with some yarn breakage, and the drawn yarn thoroughly washed with carbon tetrachloride had a very soft texture and did not have the squeaky feeling inherent to polyester.

Comparative Example 1 The same operation as in Example 2 was carried out without adding anything to 100 parts by weight of a polyester resin having an intrinsic viscosity of 1.0.

As a result, the intrinsic viscosity of the chipped material after melting is 0.
．． 85, The pressure of the nozzle part during spinning is 75 kgf/cff
The intrinsic viscosity of the undrawn yarn was 0.67.

Table 3 shows the yarn breakage frequency and yarn strength when the stretching ratio was changed.

Table * O: No yarn breakage at all ΔD Some yarn breakage ×: Almost no yarn breakage Undrawn yarn and drawn yarn thoroughly washed with carbon tetrachloride had squeaks.

From Example 2 and Comparative Example 1, distearylpyromellitic acid diimide, which is a melt viscosity reducing agent for polyester resin of the present invention, has the effect of lowering the discharge pressure during spinning, and its durability remains unchanged even after washing with carbon tetrachloride. It can be seen that it has the ability to improve the texture of the product. Furthermore, in terms of drawing behavior, there is an effect of reducing yarn breakage during drawing and increasing the drawing ratio, and it can be seen that the addition of the compound according to the present invention does not deteriorate the yarn strength.

Such characteristics of the compound according to the present invention are presumed to be due to the fact that this compound exhibits a special orientation distribution in the system.

FIGS. 1 and 2 are X-ray photographs showing small-angle X-ray scattering images of the 4-fold drawn yarns obtained in Comparative Example 1 and Example 2, respectively.

As can be seen from FIG. 2, the yarn containing distearylpyromellitic acid diimide has a diffraction pattern oriented outside the long-period diffraction pattern inherent to polyester. This peak corresponding to a lattice spacing of 47 people corresponds to long-period diffraction of distearylpyromellitic acid diimide alone, and it is clear that this compound is oriented and crystallized in the polyester fiber.

Example 3 In Example 2, an experiment similar to Example 2 was conducted using the compounds shown in Table 4 instead of distearylpyromellitic acid diimide, and the nozzle pressure during spinning, the viscosity limit of undrawn yarn, and The texture of the undrawn yarn was examined.

The results are shown in Table 4. table ,

[Brief explanation of drawings]

FIGS. 1 and 2 are X-ray photographs showing small-angle X-ray scattering images of the 4-fold drawn yarns obtained in Comparative Example 1 and Example 2, respectively.

Claims (1)

[Claims] 1 Represented by general formula (1) ▲ Numerical formulas, chemical formulas, tables, etc. ▼ (1) (In the formula, R represents carbon and a straight chain alkyl group having 12 to 22 atoms.) Melt viscosity reducing agent for polyester resin consisting of a compound. 2 General formula (1
) A polyester fiber obtained by melt-spinning a polyester resin composition obtained by adding and mixing a compound represented by: 3. The polyester fiber according to claim 2, wherein the raw polyester resin is a polyester resin whose main repeating unit is ethylene terephthalate. 4. The polyester fiber according to claim 2 or 3, wherein the amount of the compound represented by general formula (1) is 0.1 to 10 parts by weight per 100 parts by weight of the polyester resin.