JPS5953368B2 - Method for manufacturing polyester staple with excellent spinnability - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a polyester stable with excellent spinnability.

Polyester fibers, particularly polyethylene terephthalate fibers, have superior physical properties compared to natural fibers or other synthetic fibers, and are widely used in the clothing and industrial fields.

In particular, polyethylene terephthalate staples are mainly used in the clothing field either alone or blended with other fibers such as cotton, rayon, and linen, but during spinning, the equipment is subject to severe wear, which greatly shortens the life of the equipment. The spinning process generates a significant amount of white powder, which causes serious operational problems such as yarn breakage, deterioration of quality, increased cleaning frequency, and deterioration of the working environment.

For example, in the spinning process, the taker-in of the card, the garnet wire, the cylinder, the metallic wire of the drawer, the top clothing, or the roller of each line tightening machine,
Various guides wear out in a short period of time, and especially in the case of air spinning machines, the combing wire has a Vickers hardness of 3000.
Even if a polyester staple is used, it has to be replaced every six to eight months due to the blend ratio of 65 polyester/35 cotton, and spinning with 0% polyester staple is hardly ever carried out.

In addition, in the spinning process, in the case of an air spinning machine, crushed fiber pieces accumulate in the rotor and cause yarn breakage, and in the case of a ring spinning machine, a significant amount of white powder adheres to the ring rail, making it difficult to operate. This is causing problems such as degrading the environment and increasing costs due to increased cleaning frequency.

Conventionally, in order to improve the spinning operability of polyester stable by solving these problems, a number of methods have been proposed to improve the crimp form of raw cotton, the fastness of crimp, the spinning oil agent, etc.

However, no satisfactory effect can be obtained by any of these methods, and there is a need for a polyester stable with excellent spinning operability and quality, and a method for producing the same.

In order to solve the above-mentioned problems, the present inventors conducted intensive research from a completely different viewpoint and completed the present invention.

That is, in the present invention, polyester fibers having a relative viscosity of 1.20 to 1.45 contain 0.05 to 2.0% by weight of polyorganosiloxane having a molecular weight of 20.000 or less, and the polyorganosiloxane is coated on the surface of the fiber. The method of the present invention provides a polyester staple with excellent spinnability characterized by having a coating film of 1.20 to 1.45 and having a molecular weight of 2
0.000 or less polyorganosiloxane from 0.05 to 2
．． Melt-spun with 0% by weight content, roller temperature 65℃
Stretching is performed at a temperature of 85°C to 85°C, then heat set at a roller temperature of 160°C to 195°C, and then crimped and stretched to 90°C.
It is characterized in that it is heat treated in an atmosphere at a temperature of 130°C to 130°C, cooled, and then cut.

The polyester in the present invention is mainly composed of polyethylene terephthalate for fiber formation using terephthalic acid as the acid component and ethylene glycol as the glycol component, and is 85 mol% or more, preferably 90 mol% in the polymer.
The above is the polyester which is polyethylene terephthalate.

Part of terephthalic acid or ethylene glycol can be converted into β-hydroxyethoxybenzoic acid, hydroxybenzoic acid, isophthalic acid, diphenylsulfone dicarboxylic acid, diphenylmethane dicarboxylic acid, diphenyl ether dicarboxylic acid, diphenoxyethane dicarboxylic acid, sodium sulfoxyisophthalic acid, Oxyacids or dibasic acids such as adipic acid and sepatic acid, as well as trimethylene glycol, tetramethylene glycol, hexamethylene glycol, pyrene glycol, 1,4-cyclohexanediol, 1,4-cyclohexane dimetatool, 1, It contains a modified polyester for fiber formation whose main component is polyethylene terephthalate which can be substituted with one or more aliphatic or alicyclic dioxy compounds such as 4-bishydroxyethoxybenzene, bisphenol A, and polyethylene glycol.

Further, the polyester may contain additives such as a matting agent, a light-fastening agent, an antistatic agent, a flame retardant, and a pigment as appropriate.

Particularly suitable polyesters for the present invention include polyhydric alcohols such as pentaerythritol, trimethylolpropane, glycerin, etc., or at least three alcohols such as trimellitic acid, pyromellitic acid, etc., in the polyester mainly composed of polyethylene terephthalate. It is a polyester obtained by copolymerizing 0.02 to 1.0 mol %, preferably 0.05 to 0.5 mol % of a branching agent such as a polycarboxylic acid having a carboxyl group.

Among these branching agents, pentaerythritol and trimellitic acid are particularly preferred in view of their favorable melting point and reactivity.

The polyester staple containing the branching agent and polyorganosiloxane significantly suppresses the generation of white powder due to friction with spinning equipment and wear of the equipment, and provides excellent anti-pilling properties.

The branching agent copolymerized into the polyester is 0,02
If it is less than mol%, no anti-pilling effect will be obtained;
If it exceeds 0 mol%, spinning becomes difficult due to an increase in melt viscosity, so it is preferable to follow the above range.

The polyester used in the present invention is prepared using a mixed solvent of equal weights of phenol and tetrachloroethane. Relative viscosity (ηrel) measured at 20°C at a concentration of 5/100ml is 1,2
The range is from 0 to 1.45, particularly preferably from 1.26 to 1.40.

When the value of relative viscosity is too low, the strength of the obtained polyester staple decreases, white powder is likely to be generated during spinning, and operability is poor.

Furthermore, if the relative viscosity is too high, wear on the spinning device will increase significantly.

In the present invention, the polyorganosiloxane added to the polymer is preferably one that does not cause decomposition of the polymer even when mixed with the polymer and melt-spun, such as dimethylpolysiloxane, methylphenylpolysiloxane, diphenylpolysiloxane. Among them, methylphenylpolysiloxane is particularly suitable because it has excellent heat resistance and dispersibility in polyester.

The molecular weight of the polyorganosiloxane suitable for the present invention is 20,
000 or less, particularly preferably 15,000 or less.

If the molecular weight exceeds 20,000, the uniform dispersibility in the polyester will decrease, the polyorganosiloxane will ooze out onto the fiber surface due to staple heat treatment, the spreadability of the coating will be poor, and the generation of white powder during spinning will be suppressed. I can't get the desired effect.

The viscosity of the polyorganosiloxane measured at 25°C is 10,
000 centipoise or less is preferable, and 6,000 centipoise or less is particularly preferable.

The polyorganosiloxane preferably has a volatile content of 1.5% or less after 24 hours at 180°C, particularly preferably 1.5% or less.
It is 0% or less.

If the volatile content is too large, operational stability during spinning and fiber quality will be reduced.

The amount of polyorganosiloxane contained in the polyester is 0.05 to 2.0% by weight, particularly 0.1 to 1.5%.
% by weight is preferred.

If it is less than this range, the desired effect of the present invention cannot be obtained, and if it exceeds this range, the uniform dispersibility in the polyester decreases, causing yarn breakage during spinning or drawing. It is desirable to use within this range.

In the present invention, the polyorganosiloxane can be incorporated into the polyester by any method such as adding it to the raw materials for producing polyester, during polycondensation, or adding and mixing it to polyester chips during spinning. However, a method in which polyorganosiloxane is added and mixed during drying of the polyester chips during spinning or immediately before spinning is particularly easy to work with.

The polyorganosiloxane-containing polyester is prepared by melt-spinning the undrawn yarn tow according to a conventional method at 65°C to 85°C.
Stretched using rollers that can be heated to 160°C
After heat setting with a roller that can be heated to 195°C, crimping is performed by a conventional method, and further 90°C to 130°C.
The heat treatment is carried out in an atmosphere at a temperature of 100°C to 120°C, particularly preferably 100°C to 120°C.

If the temperature during stretching and heat setting during this process is outside the above-mentioned processing temperature range, the generation of white powder will be significantly increased, and a tow with uniform physical properties will not be obtained.

The number of crimps imparted by the crimping process is 10 to 25 times/25
mm is preferred, and 13 to 20 times/25 mm is particularly preferred.

If the number of crimps is less than the above range, droplets are likely to occur during the spinning process, resulting in reduced spinning operability.

If it exceeds the above range, the licking of the wrap will increase and the spinning operability will deteriorate.

The heat treatment is either dry heat or warm heat, and from the viewpoint of the morphological stability of the crimped tow, dry heat treatment is preferred, and the treatment is preferably carried out for at least 30 seconds. It oozes out to form a film that gives the surface smoothness.

At this time, if the temperature is below the above range, the effect cannot be obtained.

Furthermore, if the temperature exceeds the above range, the crimps imparted in the previous step will loosen or disappear, so it is preferable to carry out the treatment within the above temperature range.

The heat-treated crimped and drawn yarn tow is cooled to room temperature or its vicinity by any method such as air cooling or blowing with cold air, and then cut by a conventional method to obtain a polyester stable with excellent spinnability.

The polyester staple of the present invention is spun in a conventional manner and significantly reduces wear on parts of spinning machines; for example, the combing wire of an air spinning machine can be used for at least twice the life of conventional equipment even at a 50% blend. Even in the case of 100% polyester, it can be used for at least 8 months.

Furthermore, in the spinning process and other processes such as winding, twisting, etc., whether using an air spinning machine or a ring spinning machine, the generation of white powder is extremely small, and the work can be carried out without causing yarn breakage or quality deterioration. It is possible to obtain excellent spun yarn with stable operability and quality while maintaining a favorable environment.

The present invention will be explained below with reference to Examples.

Example 1 Dry chips of polyethylene terephthalate having a relative viscosity (ηrel) of 1.38 copolymerized with 0.2 mol% of pentaerythritol were coated with a molecular weight of 6000 and a viscosity of 5000.
centipoise (25℃), volatile content 0.5% (180℃
, 24 hours) was added in a predetermined amount, mixed in a tumbler-type blender, fed to an extruder, and melted at 285°C in a conventional manner to obtain 1200 m
/min to obtain an undrawn yarn tow.

The undrawn yarn tow was bundled to 500,000 niels in terms of drawn yarn, and heated to 75°C using a roller that heated the yarn to 3.97 mm.
It is stretched twice and then heat-set with a roller that can be heated to 190°C, then a spinning oil mainly containing potassium lauryl phosphate salt is applied, crimped, treated at a predetermined heat treatment temperature, and then cut to lengthen the fibers. 38mm, fineness 1.39
Got denier staples.

The resulting stable was blended with cotton and 50150 sliver, and spun into yarn of 20 count using an air spinning machine. Table 1 shows the number of yarn breaks and the state of white powder generation.

As is clear from the above table, the crimped shape of the drawn polyester crimped yarn tow containing 0.05 to 2.0% by weight of polymethylphenylsiloxane was heat-treated at 90°C to 130°C. By spinning the staples, a homogeneous spun yarn with very little yarn breakage and white powder generation was obtained.

In particular, the amount of polymethylphenylsiloxane added is 0.01
The effect is remarkable when the content is 1.5% by weight and the heat treatment temperature is 100°C to 120°C.

In addition, it was observed that the raw cotton of the polyester staple according to the present invention tends to have less wrap and bulk, and has a reduced retentivity capacity compared to the conventional polyester staple that does not contain polymethylphenylsiloxane. The properties were good.

Example 2 0.3% by weight of polydimethylsiloxane having a different molecular weight was added to dry chips of polyethylene terephthalate having a relative viscosity (ηrel) of 1,367, and the mixture was spun, stretched, heat set, and wound in the same manner as in Example 1. Shrinking process and 10
After heat treatment at 0℃, the fineness is 1.4 denier and the fiber length is 3.
8mm staples were manufactured.

In this case, staples with different crimp rates were obtained by varying the conditions in the crimp process.

These polyester raw cottons are made into polyester 6 through a filament process.
Table 2 shows the results of spinning a 45-count yarn using a ring spinning machine with a blend of 5/35 cotton.

As is clear from the above table, when the molecular weight of dimethylpolysiloxane was 20.000 or less, the occurrence of thread breakage and loose powder during the spinning process was extremely small, and the operability was excellent.

Incidentally, the occurrence (grade) of white powder shown in Table 2 was classified into the following three grades.

Also, the number of crimp is 10 to 25 times/25mm, especially 13 to 20
When the number of turns/25 mm is less than the above range, yarn breakage occurs frequently due to slippage, and when it exceeds the above range, the licking of the wrap increases and reduces the spinning operability. there were.

Example 3 Relative viscosity (ηrel) 1.27 (A
), 1, 38 (B), and 1.42 (C) by adding 0.3% by weight of polymethylphenylsiloxane to polyethylene terephthalate dry chips, respectively. Treatment was carried out at various temperatures, followed by crimping and heat treatment at 90° C. to obtain staples with a fiber length of 38 mm and a fineness of 1.39 denier.

Using the stable alone, a 40-count yarn was spun using a ring spinning machine, and the generation of white powder was classified according to the determination method shown in Example 2.

The results are shown in Table 3.

As is clear from the table above, the temperature of the stretching roller is 65°C to 8°C.
5℃ and heat set roller temperature 160℃~195℃
By treating the undrawn yarn tow of polyethylene terephthalate containing polymethylphenylsiloxane under conditions of .degree. C., it was possible to suppress the generation of white powder during spinning.

Example 4 Relative viscosity (ηrel) obtained by changing the copolymerization ratio of pentaerythritol in Example 1 and further copolymerizing trimellitic acid instead of pentaerythritol.1.
0.2 of polymethylphenylsiloxane having a molecular weight of 9,000, a viscosity of 6,000 centipoise (at 25°C), and a volatile content of 0.45% (at 180°C for 24 hours) was added to dry chips of polyethylene terephthalate having a molecular weight of 35 to 1.38. % by weight and melt-spun in the same manner, and the resulting undrawn yarn tow is stretched, heat-set, and crimped under the same conditions and heat-treated at 100°C to obtain polymethylphenyl contained inside the fiber. A coating was applied by exuding siloxane onto the fiber surface, and the fiber was cut to obtain a staple having a fiber length of 38 mm and a fineness of 1.37 denier.

The resulting staples were each made of 65% polyester and 35% cotton.
% of the sliver, produced a 20 count spun yarn using an air spinning machine, measured the amount of yarn breakage and powder generated at that time, and further produced a plain weave woven fabric with a basis weight of 100 g/m' from the spun yarn. C
A test was conducted for 5 hours at 5 Qr, p, and m using a type I pilling tester to determine the pilling resistance (grade).

The results are shown in Table 4. As is clear from the above table, the staple produced by the method of the present invention has a remarkable effect in that thread breakage and generation of white powder during spinning are small.

Furthermore, 0.02 to 1.0 mol% of branching agent, especially 0.05 to 0
．． Polyethylene terephthalate copolymerized with 5 mol % was able to impart extremely excellent pilin resistance due to its mutual effect with methylphenylpolysiloxane.

Furthermore, the raw cotton of samples A5 and A16 was made of polyester 65.
A long-term spinning test was conducted using three spindles using a blend ratio of 35/cotton, and the result was that the combing wire of the conventional product using raw cotton that does not contain polyorganosiloxane was a carbide type with a Vickers hardness of 3000. The durability limit is 6 to 8 months, and when the raw cotton according to the present invention was used, no problems were observed even after 10 months, and it was found that the wear of the spinning machine was extremely small.

Claims (1)

[Scope of Claims] 1. Polyorganosiloxane having a molecular weight of 20.000 or less is mixed into a polyester having a relative viscosity of 1.20 to 1.45.
05 to 2.0% by weight, melt-spun, stretched at a roller temperature of 65°C to 85°C, then heat set at a roller temperature of 160°C to 195°C, and then crimped at 90°C. A method for producing a polyester staple with excellent spinnability, which comprises heat-treating in an atmosphere at a temperature of 130°C to 130°C, cooling, and then cutting. 2. The method for producing a polyester stable with excellent spinnability according to claim 1, wherein the heat treatment temperature is in the temperature range of 100°C to 120°C. 3. The method for producing a polyester stable with excellent spinnability according to claim 1 or 2, wherein the heat treatment is a dry heat treatment.