JPH11172528A - Production of polyester melt-forming product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a polyester melt-forming product excellent in quality and useful for clothes, etc., by which dirt deposited on a spinning cap is decreased, an amount to be extruded is increased, productivity is improved, and energy and labor are saved by melt-forming a polyester including carbon dioxide provided by absorption or the like. SOLUTION: A polyester such as polyethylene terephthalate absorbing and/or adsorbing carbon dioxide is subjected to melt-forming or melt-spinning to provide a polyester melt-forming product or a polyester fiber in the method for producing the polyester melt forming product. Preferably, a melt-spinning apparatus of the polvester includes a single screw or twin screw extruder, and the spinning speed is 3,000-12,000 m/min. The spinning temperature is preferably Tm+20 deg.C (Tm is a melting peak temperature of the polyester measured by a DSC). The obtained fiber is preferably drawn or subjected to a draw-false twist texturing, and the drawing temperature is preferably not higher than the glass transition temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyester melt molding method, and more particularly, to a melt spinning method capable of improving productivity and saving energy and labor.

[0002]

2. Description of the Related Art Polyester fibers have various excellent properties including mechanical properties, and are therefore widely used in apparel and industrial materials.

[0003] In recent years, particularly in the production of polyethylene terephthalate (hereinafter abbreviated as PET) fibers, the take-up speed in spinning is increased to 5000 m / min or more, and high-speed spinning is performed to obtain practical fibers in one step without stretching. The law has been adopted industrially. Since the productivity in the spinning process greatly depends on the discharge amount per unit time, the higher the speed, the higher the productivity of such a one-step method.
Also, in the conventional two-step method, if an undrawn yarn having the same elongation can be obtained by high-speed spinning, the productivity is improved accordingly.

Conventionally, JP-A-56-9103, 57-11211, 58-14
No. 4,117,60-209015, a method of high-speed spinning by blending a specific polymer with polyester as disclosed in JP-A-7-504717 and the like, and JP-A-53-292, 58-18661.
1, a method of high-speed spinning by copolymerizing a specific branching agent with a polyester as disclosed in JP-A-63-75112, etc., which is disclosed in JP-A-61-111358 and JP-A-5-195320. As described above, a method of dispersing specific particles in polyester and spinning at high speed is known. Recently, a method of spinning a composite with a specific polymer has been disclosed in JP-A-8-246247. However, any of these methods requires polymer modification and new equipment investment, and there remains a problem in terms of cost even if the discharge amount is increased and the productivity is improved.

[0005] Further, usually, melt spinning of polyester is performed by T
m (the peak melting temperature of the polyester polymer as measured by DSC) + 25-40 ° C. However, at a high spinning temperature of 285 ° C. or higher, sublimation and bleeding of particles such as discharged polymer and titanium oxide, yarn breakage due to die contamination due to deposition, and spinning are temporarily interrupted to clean the die contamination, and the accompanying A large amount of lint was generated and productivity was reduced. In addition, it was also essential to secure personnel for cleaning the base dirt.

[0006] Regarding the reduction of the base stain, a method of optimizing the base hole dimension as disclosed in Japanese Patent Application Laid-Open Nos. 63-120109 and 1-168907 has been proposed. No. 270807, a method of modifying the material of a die as disclosed in JP-A-52-32709, and
As disclosed in Japanese Patent Publication No. 2, a method of sealing under a base with a gas such as nitrogen or carbon dioxide or water vapor is disclosed. However, the unit cost of the base and the investment in equipment for sealing under the base were large, and in addition, the quality of thread spots and the like was lowered, and the problem was not solved.

[0007]

SUMMARY OF THE INVENTION The object of the present invention is to improve the productivity by increasing the discharge amount and reducing the contamination of the base by a simpler method than in the prior art, thereby achieving a substantial cost reduction.

[0008]

The above object is achieved by a method for producing a polyester melt-molded product, which comprises melt-molding a polyester having carbon dioxide absorbed and / or adsorbed thereon.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. Examples of the polyester include polyethylene terephthalate, polypropylene terephthalate, and polybutylene terephthalate, and polyethylene terephthalate is most commonly used and is preferred.

The polyester may be one in which a part of the diol component and a part of the acid component are each substituted with another copolymerizable component within a range of 15 mol% or less. They may also contain additives such as matting agents, flame retardants, antistatic agents, pigments and the like.

According to the present invention, in the melt molding of polyester in which carbon dioxide is absorbed and / or adsorbed, in particular, in melt spinning, the spinning speed is increased as compared with the ordinary, productivity is improved, and energy can be saved by setting the spinning temperature low. . The reason for this is not clear, but for example, K. Mizoguchi et al.,
Polymer, vol. 28, p1298-1302 (1987); and D. Knittel et a
As described in l., Angew. Makromol. Chem., vol. 218, p69-79 (1994), etc., it is possible that the absorbed and / or adsorbed carbon dioxide acts as a plasticizer for the polyester. It is considered to be the cause.

In the above-mentioned literature, carbon dioxide is absorbed and / or adsorbed on solid polyester. However, this requires a long-term treatment (more than several hours) under high pressure or a severe condition of supercritical carbon dioxide. It is not practical to use it as it is for forming polyester. However, in the present invention, it is preferable to absorb and / or adsorb carbon dioxide on the polyester before molding, that is, in a molten state. In particular, when a single-screw or twin-screw extruder is used, carbon dioxide undergoes compression (high pressure). Since the stirring is performed for a certain period of time, the absorption and / or adsorption of carbon dioxide is particularly efficiently performed.

It is very difficult to absorb and / or adsorb carbon dioxide after discharging the polyester from the die hole. For example, there is a method of sealing under a die with carbon dioxide in melt spinning, but the contact time between carbon dioxide and polyester is very short, and the efficiency is low and the effect is low, and carbon dioxide is efficiently absorbed and / or adsorbed. Therefore, it is inferior to the present invention in that high pressure conditions require a large capital investment.

The extent to which the spinning speed is increased and the spinning temperature is lowered depends on the amount of carbon dioxide absorbed and / or adsorbed on the polyester. That is, the higher the carbon dioxide absorption and / or adsorption amount, the higher the spinning speed. Usually, a sufficient effect is exhibited if the amount of carbon dioxide absorbed and / or adsorbed is 0.2% by weight or more.
The absorption and / or adsorption amount of carbon dioxide can be estimated as follows. First, about 50 g of the molten polyester discharged from the die hole in the melt spinning is cooled at a position 30 cm below the die in a water tank and sampled. Next, the weight was measured immediately after removing excess water by a high-pressure air flow, and compared with the weight 96 hours later,
The absorption and / or adsorption amount of carbon dioxide can be known.

A known method can be adopted for the method of supplying carbon dioxide, the method of introducing it into the melt spinning apparatus and its accompanying apparatus (such as a polymer chip bunker), but is not particularly limited. However, in order to prevent degradation of the polyester due to hydrolysis, it is preferable to use dry carbon dioxide from which water has been removed.

The method for absorbing and / or adsorbing carbon dioxide is not particularly limited. This will be described below with reference to the drawings. Conventionally, polyester melt spinning is sealed with dry nitrogen throughout the entire process from drying the polyester chip to discharging the molten polymer from the die 7 to prevent the incorporation of moisture, but by applying dry carbon dioxide instead of dry nitrogen. The polyester can absorb and / or adsorb carbon dioxide. By sealing at least the inside of the polymer melting device 3 to the inside of the spinning pack 5 with dry carbon dioxide, sufficient absorption and / or adsorption is achieved. However, the absorption of carbon dioxide by polyester and / or
Or, considering that the adsorption is more stable when the polyester is in contact with the polyester for a long time, and considering the overall efficiency of the utility, the dry carbon dioxide seal is preferably from the chip pipe 2, more preferably from the polymer chip bunker 1, and further more preferably. Is after chip drying.

Known melt spinning and winding devices can be used as they are, but it is preferable to use a single or twin screw extruder as the polymer melting device 3. This is because although the absorption and / or adsorption of carbon dioxide in the polyester is more advantageous when the pressure of carbon dioxide is higher, the apparent carbon dioxide pressure can be increased because a compressive force acts on the polymer during the melting / transfer process in the extruder. That's why. Further, in the extruder, expansion / compression of carbon dioxide also occurs, so that the pressure of carbon dioxide further increases, which is preferable. Note that a conventionally known extruder can be used. The number of the axes is preferably two from the point of improving the contact efficiency between the carbon dioxide and the polyester rather than one, but considering the cost increase by using the twin-screw extruder, the number of the axes of the extruder is considered in consideration of both. May be determined.

According to the present invention, a fiber having the same residual elongation can be obtained even if the spinning speed is increased as compared with ordinary polyester melt spinning. That is, the discharge amount per unit time increases, and the productivity can be improved. At this time, the spinning speed is 3
When the molecular weight is 000 to 12000 m / min or more, the molecular orientation is appropriately advanced, so that the fiber can be used for drawing or drawing false twisting or can be used as it is. Preferably, the spinning speed is 4000 m / min or more.

Even if the melt-spun yarn is taken up as it is, or once taken up by a first hot roll, stretched between second hot rolls, and heat-fixed and wound up (so-called direct spinning), it is formed on a spinning wire. Once cooled to below the glass transition temperature of the polymer, it may be passed through a non-contact hot tube, stretched by heating and then wound up.

Usually, the polyester fiber is drawn at a glass transition temperature of about 5 to 20 ° C. (80 to 95 ° C. for PET) in consideration of yarn breakage during drawing and drawing uniformity. Can be obtained at a temperature equal to or lower than the glass transition temperature, and the same quality as that of a normal polyester drawn yarn can be obtained. For this reason,
The stretching process can also contribute to energy saving.

In the present invention, the spinnability is good even if the spinning temperature is set lower than usual, compared to ordinary polyester melt spinning, and it can contribute to energy saving. The spinning temperature can be set to Tm + 20 ° C. or less. However,
If the spinning temperature is Tm-10 ° C. or lower, the spinnability decreases, so it is preferable to set the temperature higher than this.

By setting the spinning temperature in this manner, sublimation and bleeding of particles such as a discharged polymer and titanium oxide can be achieved.
Dust contamination due to deposition can be significantly reduced. For this reason, it is possible to reduce the amount of thread breakage due to dirt, the generation of debris due to the cleaning of the die, and the number of debris sorting and die cleaning personnel, thereby improving the yield and saving labor.

When the fiber obtained according to the present invention is made into a woven or knitted fabric and left to stand in the air, the absorbed and / or adsorbed carbon dioxide is released to form microvoids in the fiber, and the fiber is dyed. This has the effect of improving the properties and hygroscopicity of ordinary polyester fiber woven and knitted fabrics, and it is possible to obtain polyester woven and knitted fabrics having better dyeability and hygroscopicity than before. Further, a deodorizing effect due to microvoids in the fiber is also provided.

The polyester fiber obtained by the present invention may be used as a raw yarn or as a twisted or false twisted yarn,
It can be suitably used for clothing such as sportswear, slacks, blousons and blouses, and for materials such as ribbons, tapes and belts.

The present invention is applicable not only to melt spinning but also to various melt molding such as film molding and injection molding.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to embodiments. In addition, the measuring method in the Example used the following method.

A. Intrinsic viscosity [η] Measured at 25 ° C. in orthochlorophenol.

B. Glass transition temperature and Tm Measure the polyester chip before absorbing and / or adsorbing carbon dioxide using a Perkin Elmer DSC 7 at a sample weight of 10 mg at a heating rate of 16 ° C./min. The endothermic peak temperature (Tm) was measured.

C. Strength and elongation A load-elongation curve was determined under the conditions shown in JIS L1013. Next, the load value was defined as the strength divided by the initial fineness, and the elongation was defined as the elongation divided by the initial sample length.

Example 1 Intrinsic viscosity 0.63, glass transition temperature 75 ° C., Tm 255
Melt spinning was performed by using the homo PET at a temperature of 0 ° C. as a polyester chip and using the melt spinning apparatus shown in FIG. At this time, after the chip drying step, sealing was performed with dry carbon dioxide.
A single screw extruder was used as the polymer melting device 3. Also,
After filtration was performed using a stainless steel nonwoven fabric filter 6 having an absolute filtration diameter of 5 μm in the pack, the mixture was discharged from a base 7 having a hole diameter of 0.25 mm, a hole length of 0.4 mm, and 36 holes. The spinning temperature was adjusted to 270 ° C., and the discharge rate was adjusted to a single yarn fineness of 4 dtex. The discharged yarn is cooled by a chimney 9 according to a conventional method after the discharge, a spinning oil is applied by an oil supply guide 10, then entangled by an interlace nozzle 11, and is fed via a take-off roller 12 (room temperature, same peripheral speed). And was wound by a winder 13. The peripheral speed of the take-off roller that the yarn first touches is shown in Table 1 as a spinning speed (Experiment Nos. 1 to 5).

The spinnability was good, and almost no die staining occurred. Further, in all spinning speed regions, an effect of improving the residual elongation was observed as compared with the ordinary melt spinning of PET (Comparative Example 1).

Comparative Example 1 Dry carbon dioxide was changed to dry nitrogen, and the spinning temperature was set to 295.
Melt spinning was performed under the same conditions as in Example 1 except that the temperature was changed to ° C (Experiment Nos. 6 to 10). A noticeable stain on the base occurs,
Many thread breaks occurred. In addition, the residual elongation of the obtained fiber at the same spinning speed was lower than that in the case where PET in which carbon dioxide was absorbed and / or adsorbed was melt-spun.

Example 2 The fiber wound in Example 1 at a spinning speed of 4000 m / min was drawn at a draw ratio of 1.80 times and a first hot roller temperature of 6
The film was stretched at 0 ° C. and a second hot roller temperature of 130 ° C. by a conventional method (FIG. 2). The stretched yarn obtained had good elongation characteristics and yarn spots. Further, when a plain woven fabric was prepared and dyed using the drawn yarn as a warp and a weft, the dyeability was good, and no staining spots or the like were generated.

Example 3 The fiber wound in Example 1 at a spinning speed of 4000 m / min was subjected to false twist drawing by a conventional method (FIG. 3) at a draw ratio of 1.83 and a heater temperature of 210 ° C. The stretched yarn obtained had good elongation characteristics, crimping characteristics and yarn spots.
Further, when a plain woven fabric was prepared and dyed using the drawn yarn as a warp and a weft, the dyeability was good, and no staining spots or the like were generated.

Example 4 A spinning temperature of 275, 265 and 255 ° C. and a spinning speed of 40
Spinning was performed under the same conditions as in Example 1 except that the speed was set to 00 m / min (Experiment N 0.11 to 13). The spinnability was good, and almost no die stain was generated. In addition, the effect of improving the residual elongation was observed as compared with ordinary PET melt spinning.

Example 5 Spinning was performed under the same conditions as in Example 1 except that the spinning temperature was 295 ° C. (Experiment No. 14). Although the base was stained, the effect of improving the residual elongation of the wound yarn was a spinning temperature of 275.
° C (Example 3).

[0037]

[Table 1] Example 6 Spinning was carried out under the same conditions as in Example 1 except that the first take-up roll and the second take-up roll were both Nelson-type heating rolls and spinning was performed by the spinning direct drawing method (Experiment No.
15). At this time, the first take-up roll has a peripheral speed of 4000
m / min, temperature 60 ° C, second take-up roll has a peripheral speed of 80
Stretching was performed 2.00 times at 00 m / min and at a temperature of 150 ° C. In this case, the temperature of the first take-up roll is the stretching temperature. The obtained wound yarn had good elongation characteristics and yarn spots. Further, when a plain woven fabric was prepared and dyed using the drawn yarn as a warp and a weft, the dyeability was good, and no staining spots or the like were generated.

[0038]

EFFECTS OF THE INVENTION By adopting the method for producing a polyester fiber of the present invention, the discharge rate per unit time is increased to improve the productivity, energy is saved at a low spinning temperature, and the yield is reduced due to a decrease in die contamination. Improvements and labor savings can be performed, and total cost reduction can be achieved.

[Brief description of the drawings]

FIG. 1 is a diagram showing a melt spinning apparatus.

FIG. 2 is a view showing a stretching device.

FIG. 3 is a view showing a stretch false twist apparatus.

[Explanation of symbols]

1: polymer chip bunker 14: undrawn yarn 2: chip piping 15: feed roller 3: polymer melting device (extruder) 16: first hot roller 4: spin block 17: second hot roller 5: spinning pack 18: cold Roller 6: Non-woven fabric filter 19: Stretched yarn 7: Spinner 20: Unstretched yarn 8: Yarn 21: Feed roller 9: Chimney 22: Heater 10: Refueling guide 23: Twister 11: Interlace nozzle 24: Second roller 12: Take off Roller 25: Third roller 13: Winder 26: False twisted yarn

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI D02G 1/02 D02G 1/02 B D02J 1/22 D02J 1/22 J D03D 15/00 D03D 15/00 A // D01D 5 / 08 D01D 5/08 Z B29K 67:00

Claims (10)

[Claims] 1. A method for producing a polyester melt-molded product, comprising melt-molding a polyester having carbon dioxide absorbed and / or adsorbed thereon. 2. The process for producing a polyester melt-molded product according to claim 1, wherein carbon dioxide is absorbed and / or adsorbed on the polyester before melt-molding. 3. The method according to claim 1, wherein the polyester having carbon dioxide absorbed and / or adsorbed thereon is melt-spun. 4. The method according to claim 3, wherein the melt spinning apparatus for the polyester includes a single-screw or twin-screw extruder. 5. The method for producing a polyester fiber according to claim 3, wherein the spinning speed is 3000 to 12000 m / min. 6. The method for producing a polyester fiber according to claim 3, wherein the spinning temperature is Tm + 20 ° C. or less. Tm: melting peak temperature of polyester polymer measured by DSC 7. The method for producing a polyester fiber according to claim 1, wherein the polyester is polyethylene terephthalate. 8. A method for producing polyester fibers, comprising subjecting the polyester fibers obtained according to claims 3 to 7 to drawing or drawing false twisting. 9. The method according to claim 8, wherein the stretching temperature is equal to or lower than the glass transition temperature. 10. A woven or knitted fabric using the polyester fibers obtained according to claims 3 to 9.