JPS5921971B2 - Polyester fiberglass - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing crimped yarn by simultaneously drawing and false-twisting undrawn polyester yarn obtained by high-speed spinning. To produce a crimped yarn of uniform quality by reducing the dyeing difference (dark dyeing) of the crimped yarn caused by changes over time in the undrawn yarn when drawing and false twisting is performed at a high speed of rpm or higher. The purpose is to

Recently, undrawn polyester yarn obtained by high-speed spinning at a spinning speed of 2500 m or more for 7 minutes (the undrawn yarn is generally
A method of producing crimped yarn by subjecting crimped yarn (abbreviated as "POY") to stretching and false twisting at the same time has been implemented.

Undrawn polyester yarn produced by such high-speed spinning has better stability over time than ordinary undrawn polyester yarn, and therefore dyeing abnormalities (dark dyeing) of crimped yarn due to changes in undrawn yarn over time are avoided. It is said that there are few problems.

On the other hand, regarding stretch false-twisting processing machines, the rotation speed of the false-twisting spindle in conventional machines was 300,000 to 400,000 rpm at most, but recently high-speed false-twisting has been developed to improve productivity by increasing processing speed. As the development of processing machines progresses, machines with a false twisting spindle rotation speed of about 500,000 to 700,000 rpm are now on the market, and it is expected that speeds will continue to increase in the future.

However, when polyester undrawn yarn (poy) obtained by high-speed spinning is processed at such high speeds, problems occur due to aging of the undrawn yarn, which did not pose a problem with conventional processing at a false twisting spindle rotation speed of about 300,000 rpm. It has been found that dyeing abnormalities occur in crimped yarns.

This indicates that the undrawn yarn obtained by high-speed spinning (POY
) However, the stability over time is far inferior to that of drawn yarn, and when the undrawn yarn is transported from a spinning factory to a drawing and false-twisting processing center far away, it may be difficult to maintain stability over time during transportation or during storage before drawing and false-twisting. This causes the undrawn yarn to change over time, and the effect of this change over time becomes significantly magnified as the processing speed increases, and when the rotational speed of the false twisting spindle exceeds about 450,000 rpm, the dyeing of the crimped yarn due to the change over time increases. It is assumed that this is due to the problem of abnormal adhesion (dark dyeing) becoming apparent.

As a result of repeated research to solve the above-mentioned problems, the present inventors found that (1) dyeing abnormality (deep dyeing) of crimped yarn is caused by molecular orientation of undrawn yarn and stretching and false-twisting processing conditions. depends on the yarn tension just before the false twisting spindle; and (2)
−Undrawn yarn produced by conventional general-purpose high-speed spinning as undrawn yarn (
By using a yarn with a higher birefringence than POY and by selecting the yarn tension just before the false twisting spindle within a specific range that is much higher than the tension commonly used in the past, The present invention was developed based on the discovery that the problem of abnormal dyeing of crimped yarn during high-speed processing can be solved.

That is, in the present invention, polyester undrawn yarn obtained by high-speed spinning is processed by a drawing false-twisting machine having a twist fixing heater and a false-twisting spindle between a supply roller and a drawing roller, at a false-twisting spindle rotation rate of 450,000. When producing a crimped yarn by performing simultaneous stretching and false twisting at rpm or more, use a birefringence index (△n) of 0.04 or more as the undrawn yarn,
In addition, the yarn tension just before the false twisting spindle during processing (
T1g/de) is maintained within the range of the following formula % [where △n is the birefringence of the undrawn yarn, and TI is the yarn tension (g/de) immediately before the false twist spindle]. This is a method for producing crimped polyester yarn.

Hereinafter, the present invention will be explained in detail with reference to the drawings.

FIG. 1 is a schematic diagram showing one embodiment of the present invention, in which 1 is an undrawn yarn package, 2 is an undrawn yarn take-out guide, 3 is a supply roller, 4 is a twist fixing heater, 5 is a false twist spindle,
6 is a stretching roller, and 7 is a winder.

In the present invention, undrawn polyester yarn obtained by high-speed spinning is unrolled from the package 1 and guided to a supply roller 3 via an undrawn yarn take-out guide 2, and between the supply roller 4 and a downstream drawing roller 6. Stretch it to a predetermined magnification with
When producing crimped yarn by imparting false twist with a false twisting spindle 5 rotating at a high speed of 50,000 rpm or more (preferably 500,000 rpm or more) and fixing the twist with a twist fixing heater 4. Applicable.

Conventionally, in draw false twisting processing, it has been thought that the yarn tension immediately before the false twisting spindle 5 (hereinafter abbreviated as "processing tension") should be as low as possible in order to suppress the occurrence of yarn breakage, fuzz, etc. during processing. The processing tension was set at about 0.17~0.
It is customary to process at a tension of about 20 g/de, but according to the research of the present inventors, by increasing the processing tension to 0.23 g/de or more, which is higher than before, the dyeing due to differences in aging can be reduced. It was found that the difference in performance was significantly reduced.

Figure 2 shows this fact, where two types of polyethylene terephthalate undrawn yarns (poy) under the same spinning conditions but different aging conditions are drawn and simultaneously false-twisted at a false-twisting spindle rotation speed of 500,000 rpm. 2 is a graph showing the relationship between the processing tension (TI) and the dyeing difference between the two types of crimped yarns obtained.

From this figure, it is clear that by setting TI≧0.23 g/de or more, the difference in dyeing of the crimped yarn is rapidly reduced.

However, even polyester undrawn yarn (poy) obtained by high-speed spinning has a birefringence of 0.
If a yarn of about 0.03 is processed at a high tension of 0.23 g/de or more, fluff will occur frequently and a crimped yarn with commercial value cannot be obtained.

However, the birefringence is 0.04 or more (preferably 0.045
~0.070) polyester undrawn yarn weighs 0.23g
Even when processed under high tension of /de or higher, almost no fuzz occurs.

Figure 3 shows undrawn polyethylene terephthalate yarns with different birefringence indexes (△n) being false-twisted at a spindle rotation speed of 500,000 rp.
2 is a graph showing the fuzzing limit processing tension (that is, the limit processing tension at which fluffing occurs frequently and the commercial value is impaired if the processing tension is increased beyond this value) when false twisting processing is carried out at the same time as drawing at m.

From FIG. 3, the higher the birefringence index (△n) of the undrawn yarn, the more it can withstand high processing tension. TI≦
It is clear that if the value is 0.16+3.3Δn, there will be no fuzz and false twisting can be performed at the same time as stretching with good processing conditions.

The reason why undrawn yarns with △n≧0.04 can withstand such high tension processing is that undrawn yarns with such advanced orientation are not stretched after coming into contact with the twist fixing heater in the drawing false twisting process. This is presumed to be because the crystallization progresses and the processing tension increases until this occurs.

The temperature of the twisted fixed heater is preferably in the range of 195 to 210°C.

If the heater temperature is lower than 195°C, preheating on the heater will be insufficient, and dye difference abnormalities will easily occur due to changes over time.On the other hand, if it is higher than 210'C, fluff will occur even in undrawn yarn with a large Δn. It becomes easier to do.

The twist coefficient a during processing is under the normally used conditions, that is, 1.0≧
It is preferable that a≧0.85 or so.

In addition, the drawing ratio depends on the processing tension (T
I) is within the above range and the elongation of the crimped yarn is approximately 20 to
It should be selected appropriately so that it is 35 Yu, usually 1.2
~1.6 times is appropriate.

In the example shown in Fig. 1, the drawn and false twisted yarn is wound up as is, but the yarn that has left the drawing roller may be reheated under overfeed of about 0 to 30 degrees and then wound up. .

On the other hand, the undrawn polyester yarn used in the present invention is made by spinning polyethylene terephthalate or a copolyester containing polyethylene terephthalate as a main component at high speed to have a birefringence of 0.04 or more, preferably 0.045 to 0.070. However, the cross-sectional shape of the filament of the undrawn yarn is not limited to the usual circular shape, but may be non-circular such as trilobal, hexalobal, and off-clobal.

Further, the denier of the undrawn yarn is preferably 100 to 300 de, but is not limited thereto.

According to the present invention as described above, undrawn polyester yarn (POY) that has been spun at a high speed is subjected to drawing and simultaneous false twisting at a false twisting spindle rotation speed of 450,000 rpm or more. It is possible to eliminate dyeing abnormalities (deep dyeing) of crimped yarns caused by changes over time, and it is possible to obtain products with uniform quality that are less affected by changes over time.

Next, examples of the present invention will be described in detail.

In addition, the measured values in each example are values obtained by the following method.

Birefringence (△n) Birefringence index (△n) was measured in a tricres phosphate using a Na light beam and inserting a Berek convensator into the optical path of an Olympus POM-If type polarizing microscope.

(B) Difference in dyeing (points) The crimped yarn to be compared is made into stockinette knitting and the score roll≠
400.0.5g/l! 2 at Q'C at melt ratio 1:100
After scouring for 0 minutes, 6.0% of Eastman Polyester Blue GLF was added to the sample as a dye and dyed at 98° C. for 60 minutes at a dissolution ratio of 1:40.

Thereafter, it was washed with water, dried, and visually evaluated.

The dyeing change (point) is the dyeing difference with respect to the standard sample,
The practical allowable limit is 0.4 points.

(C) Number of fuzz (co/cheese) The number of fuzz on both end faces of a package wound with 3 kg of drawn and false twisted yarn was measured.

In practice, there is no problem if the number is 3 or less.

(D) Intrinsic viscosity [η] It was determined from a 35°C solution of 0-chlorophenol.

Example 1 Polyethylene terephthalate chips with [η) = 0.65 were melt-spun using a normal spinning method to obtain 230 denier/30 filaments at a spinning take-off speed of 3400 m/min, and undrawn with △n・0.046. Got the thread.

The obtained undrawn yarns were heated at 23°C x 80% RH for 2 hours.
0 days and 20 days at 40°C x 50% RH.

Both undrawn yarns were false-twisted using a stretching and simultaneous false-twisting machine with a spindle rotation speed of 500,000 rpm, and the number of twists was 2 at a heater temperature of 195°C.
Processing tension (T
Table 1 shows the results of comparing the difference in dyeing of the crimped yarns obtained by changing I) and simultaneously stretching and simultaneously false-twisting the yarns.

It can be seen from this that when the processing tension (TI) is 0.2:Ill/d or more, the difference in dyeing due to changes over time is significantly reduced.

The processing tension generally employed is 0.15 to 0.
20 g/d e and /161.2 is an example in which a conventional processing tension is adopted.

Example 2 Using the spinning method of Example 1, after simultaneous stretching and false twisting, 150
Denier/30 filament spinning take-off speed 2
000m/min, 2500m7min, 3000m7min,
3200m/min, 3400m7min, 3600m/min,
Spinning was performed at 4000 m/min.

All the obtained polyethylene terephthalate undrawn yarns were
After aging in 5°C x 65SRH for 14 days, Example 1
Using the same processing method, the processing tension (T1) is approximately 0.23,
The stretching ratio was determined to be 9/d, and false twisting was performed at the same time as stretching.

Table 2 shows Δn of the undrawn yarn and the number of fuzz of the obtained crimped yarn.

* From this, it can be seen that if Δn is 0.040 or more, it can withstand a processing tension of 0.26 g/d based on the number of fluffs.

Example 3 Among the polyethylene telescrate undrawn yarns of Example 2, the spinning take-off speed was 3200 m/min to 4000 m/min.
m/min. under the same stretching and simultaneous false twisting processing conditions as in Example 1, the processing tension was varied to determine the fuzz generation limit processing tension.

From this, the fuzz generation limit processing tension T I (j!/d)
When Δn is calculated, T I =0.16+3.3Δn, and when Δn is 0.04 or more, T1≦0.16+3.
If 3Δn, fluff will not occur.

[BRIEF DESCRIPTION OF THE DRAWINGS] Fig. 1 is a schematic diagram of a drawing/false twisting processing device showing one embodiment of the present invention, and Fig. 2 is a drawing and simultaneous drawing of two types of polyester undrawn yarns (POY) with different changes over time. A graph showing the relationship between processing tension TI during twisting and dyeing difference of crimped yarn,
FIG. 3 is a graph showing the relationship between Δn and fluffing limit processing tension of polyester undrawn yarn (POY). In FIG. 1, 1 is an undrawn yarn package, 3 is a supply roller, 4 is a twist fixing heater, 5 is a false twist spindle, 6 is a drawing roller, and 7 is a winder.

Claims (1)

[Claims] 1. Undrawn polyester yarn obtained by high-speed spinning,
Using a drawing false-twisting machine having a twist fixing heater and a false-twisting spindle between a supply roller and a drawing roller, the drawing and simultaneous false-twisting process is performed at a false-twisting spindle rotation speed of 450,000 rpm or more to produce a crimped yarn. In this case, the undrawn yarn should have a birefringence (△n) of 0.04 or more, and the yarn tension (TNi'/d) immediately before the false twist spindle during processing should be
e) to be kept within the range of the following formula % [where △n is the birefringence of the undrawn yarn, and T1 is the yarn tension (,9/d e ) immediately before the false twisting spindle]. A method for producing crimped polyester yarn characterized by: