JPS6032723B2 - Melt spinning method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a process for producing synthetic fibers from thermoplastic polymers by melt filament and drawing. is increased by the degree of stretching required for a given textile product.

Drawing can be operated as a completely separate process after winding and storage of the spun filaments, or drawing can be carried out immediately after spinning by advancing the spun filaments directly into the drawing process at a controlled speed without interruption. Alternatively, as in BP1487843, intermediate speed control between spinning and drawing can be removed and integrated with spinning. Increasing paper yarn speed increases production speed, but also increases pre-orientation, reducing filament elongation and the degree to which the filaments can be drawn. This has various disadvantages in various cases. Certain speed ranges resulted in unacceptable product scatter at practical speeds; methods aimed at very high strength filaments resulted in reduced strengths;
(drawprocess), the subsequent reduction in draw ratio reduces the required weave in grade yarns, offsetting the yield advantages of high speed paper yarns. Various methods have been proposed to alleviate this drawback in the production of polyethylene alephthalate fibers by suppressing the preorientation induced during spinning. These methods include the use of thermal tubes to reduce the cooling rate of the filament below the spinneret (B.P. 900009); the use of a forced high-velocity fluid environment instead of a substantially static fluid environment to control the elongating filament; Bias towards the high-temperature castle near Spinneret (
B. P. 1268908); Improving the flow properties of polymers using branching agents such as pentaerythritol (B.P.
1553020) is included.

In accordance with this invention, a fiber-forming thermoplastic polymer selected from polyethylene terephthalate and hexamethylene adipamide is supplemented with a small amount of polymer capable of forming a heterotropic melt in the temperature range at which the thermoplastic polymer can be melt-spun. In addition,
Both combinations are then melt spun together in the form of an intimate mixture at a minimum winding speed of greater than 1 mm/min, without added polymer and at a lower winding speed. The present invention provides a method for melt-spinning a fiber-forming thermoplastic polymer, which is characterized in that it produces fibers having properties that the fibers have. According to the present invention, a thermoplastic polymer fiber containing a small amount of a polymer capable of forming a heterotropic melt in a temperature range capable of melt-spinning the thermoplastic polymer, and drawn at a winding speed of greater than 1 article/min. I will provide a.

The process of the invention is suitable for use with very common fiber-forming thermoplastic polymers such as polyesters, polyamides, copolyesters, copolyamides or polyolefins, such as polyethylene terephthalate and its copolyesters, poly-caproamide, polyhexamethylene azide, etc. Suitable for melt spinning of pamidopolypropylene, etc. This method is
Other fiber-forming polymers such as acrylic polymers, vinyl chloride or vinylidene chloride polymers, polystyrene, polyphenylene oxide and polyphenylene oxide/
polystyrene mixtures, polysulfones and polyethersulfones, polyketones and polyetherketones,
Also suitable are melt paper yarns of polyfluoro-olefins, polyoxymethylene, thermoplastic cellulosic polymers, and other biologically produced polymers such as poly(hydroxybutyrate). However, the method of the present invention is particularly suitable for polyethylene terephthalate (PET) and polyhexamethylene adipamide (nylon 6,6) fused bush yarns.

The anisotropic melting temperature range of the added polymer and the paper yarn possible temperature range of the host polymer overlap by at least 500°C, preferably by more than 500°C, and 0.1 to 1 t% of the added polymer is blended into the mixture. is preferred.

``Polymer capable of forming a heterotropic melt'' refers to a polymer that forms such a melt when heated to a specific temperature range, which is a property of the polymer (this type is called ``thermotropic''). ``polymer'') or by applying a shearing force to the melt to form such a melt.The latter condition is
It is characterized by maintaining an anisotropic state for 1 to 2 seconds after the melt is stopped. This can be distinguished, for example, from the known observation that polyethylene terephthalate melts exhibit order when scaled through a tube. Such order disappears as soon as the melt is stopped. Some polymers exhibit both thermotropism and shear force-induced anisotropy. Polymers exhibiting such anisotropic melt behavior have been referred to as liquid crystal polymers (hereinafter LC polymers). The fiber-forming, melt-spunable polymer to which the LC polymer is added is referred to as the "host polymer."

Some test methods to determine whether a polymer exhibits anisotropic melt behavior include B. P. 1507207. A number of patent specifications describing LC polymers have been published in the 1970s. In general, any known LC polymer can be used with the present invention as long as it can be processed in the same melt temperature range as the host polymer and does not chemically react with the host polymer during melt processing resulting in significant polymer degradation. Can be selected for addition to coalescence. For use with polyesters as host polymers, especially polyethylene terephthalate, one of the many known anisotropic LC polyesters is preferably used 1'.

The LC polymer used in Examples 1 to 4 was copoly(chloro-
1,4-phenylene dioxy-4,4'-dibenzoatenoterephthalate) (CLOTH) and a copolymer of 6-oxy-2naphthyl and p-oxybenzoyl moieties in a molar ratio of 60%/40% (CO)
These LC polymers have been found to be particularly suitable. Polyamide especially nylon 6,6 as host polymer
For use with CLOTH, as shown in Examples 5-7,
CO and ethylene terephthalate/p-oxybenzoate copolymers have been found to be particularly suitable.

The effect of the LC polymer is that the wind-up speed (WUS) suppression, a property possessed by spun bifibers, is a property obtained with fibers spun at low WUS.

Certain properties of PET or nylon 6,6 are
, continuously rising or falling. These properties are therefore used to measure the degree of WUS suppression.
In the case of PET, the two main properties used are the birefringence index and the elongation at break of the spun fibers determined with an instron meter. Since birefringence normally increases smoothly as WUS increases, a decrease in birefringence at a given WUS is an indicator of WUS suppression. Since elongation at break decreases with increasing WUS, an increase in elongation at break is an indicator of WUS suppression. - In PET, there is another property of the spun fibers that passes through a certain maximum with increasing WUS and is dominated by WUS, and this is the total paper-starting boiling water shrinkage (SYS).

In this SYS, birefringence and elongation to break are not completely quantitatively related in indicating the degree of WUS suppression, but the semi-quantitative effects are similar. The results shown in Table 3 and Figure 1 show that the SYS at a given WUS varied considerably, resulting in an inverted U-shaped SYS/WUS curve shifted to the right with a slight change in scale. . nylon 6,6
In this case, elongation at break is used in a similar manner as for PET.

On the other hand, the use of birefringence is complicated. This means that the total birefringence of the Oride Tsuzuri is high WUS, which maximizes the effectiveness of the LC polymer.
This is because the birefringence tends to become constant at , and there is also an increase in the birefringence after spinning, which complicates the measurement. For the above reasons, birefringence could not be used for nylon 6,6.
Instead, another parameter was chosen that increases smoothly with increasing WUS, and that is the true stress at 50% elongation derived from the Instron stress/strain curve of the edged fibers. The invention will be illustrated in the following examples.

Examples 1 and 2 In these examples, copoly(chloro-1,4-phenylene ethylene dioxy-4,4-dibenzoate noterephthalate) (CLOTH) was used as the LC polyester.

This copolymer has the following formula (508%>(25mol%), and (25 mol%) It essentially consisted of units of

This copolymer contains chlorohydroquinosodiacetate,
Prepared according to Example 3 of USP 3,991,013 from ethylenedioxy-4,4'-dibenzoic acid and terephthalic acid. This polymer was prepared at 25q0 in a 0.5% solution in a solvent of 30% trifluoroacetic acid and 70% dichloromethane.
It had an intrinsic viscosity of 0.5 legs/g. This polymer melts in the range of 220-23000 and LeibSMP
Boitz hot stay attached to OL model deflection microscope
It becomes a heterotropic melt up to 320 oo when observed in the microwave. This anisotropic melt temperature range is very suitable for paper yarning in the temperature range of 270 to 30,000 °C with polyethylene terephthalate host polymers. In Examples 1 and 2, the LC polyester was compounded with commercial grade polyethylene terephthalate host polymer at concentrations of % runout and 6 wt%, respectively.

The mixed bran was produced in a M single screw extruder with L/D ratio of 32:1, feed zone temperature of 23000, barrel temperature of 280, 270, 265 and 27500, die temperature of 23000 and operating at 400 pm. A lace having a diameter of 3'8 inches was extruded, water-cooled, and cut. As a control, polyethylene terephthalate was extruded in the same process without the addition of LC polyester. After extrusion, the intrinsic viscosity of the control measured in trifluoroacetic acid was 0.
．． It was 59. These polymers were melt paper threaded in a 15 mil spinneret hole at 40 minutes/hour/hole and cooled to ambient air without special quenching equipment. After cooling, the formed filaments were wound at winding speeds (WUS) of 1, 2 and 4 b/min without adjusting the spinning speed, higher winding speeds yielding thinner filaments. The melt spinning temperatures obtained are shown in Table 1 along with the % elongation at break of the filaments. The intrinsic viscosity of the control after spinning was 0.58, 0.56 for the 3% blend, and 0.54 for the 6% blend. In these Examples and Controls, WUS suppression was simply compared with filament elongation at break as determined by an Instron tester.

In this and the following examples, the gauge length used was 1
At zero skin, the elongation rate was 200%/min. If the tread filament has an elongation at break E, the maximum subsequent draw ratio that can be applied is approximately (10E/100).

If the secondary filament has a larger elongation at break 8, a larger draw ratio (approximately 10E'/10
0) can be added. At these maximum draw ratios, the same fineness d
To make drawn filaments of
) must be in decitex. If both filaments are spun at the same speed, the production will be proportional to their decitex, and the percentage increase in productivity of the second filament will be (10E''10 - (10E'100)XI).

〇(10E'100).

This is the function shown in Table 1 as % productivity increase.

Table I Table 1 reveals that the increase obtained in productivity increases with increasing amount of LC polymer and increasing paper yarn speed.

At 4 loops/min, the addition of 6M% improved the productivity by about 60%.

Examples 3 and 4 In the following examples, three polymers were mixed at fine t% concentrations with commercial grade polyethylene terephthalate (
PET) host polymer and L/D ratio 32:1 supply belt 23
000, barrel temperature 280, 270, 265 and 27
500, milled in a single-screw extruder with a die temperature of 250 and operated at 4 pm, with a diameter of 3'
Eight inch lace was extruded, water cooled and cut.

The three types of added polymers were as follows.

A Commercial grade polyjethylene (PE) with melt flow index 200, Nkathene grade 23.

The reason for choosing this grade is that 1 is s at 104N/me.
It has a melt viscosity of /, which is 1 of the following B LC polymer
PiN/Mede4. This is because it is very similar to the melt viscosity of s/〆. B Copoly(chloro 1,4-phenyleneethylenedioxy-4,4'-dibenzoate/terephthalate) (CLOTH) prepared in Example 3 of USP 3991013. This polymer is trifluoroacetic acid 3
A 0.5% solution in a solvent of 0% and 70% dichloromethane had an intrinsic viscosity of 0.5 mm/g at 2500. The polymer melts in the range of 220-230qo,
The result was a melt that was heterotropic up to 320° C. when observed on a Jtz hot stage attached to a ZSMPOL model polarizing microscope. This anisotropic melting temperature range is 270 to 30°C with polyethylene terephthalate host polymer.
It is particularly suitable for spinning at temperatures in the range of 0.000 to 0.000. C
Molar ratio 6 prepared according to Example V of USP 4161470
0%/40% copolymer of 6-oxy-2-naphthyl and p-oxybenzoyl moieties (CO).

This copolymer contains 0.1% of bentafluorophenol.
Intrinsic viscosity at 60°C in solution: 5. It had a red color of 1/g. The copolymer melted at approximately 30,000 °C and became a heterotropic melt as observed with a SMPOL hot stage polarizing microscope. The intrinsic viscosity of the formulations and the resulting fibers, measured in trichloroacetic acid, are shown in Table 2.

All three polymer formulations in Table 2 and the PET control were melt spun at 98 g/hr/hole in a 9 mil spinneret hole and cooled in ambient air in a special quench device.

After cooling, the filaments obtained were wound at various speeds and the optical birefringence and boiling water shrinkage were measured and are shown in Table 3. A load/elongation curve was created for each filament. The % elongation at break was measured at each load/elongation curve and used as an evaluation of the draw ratio at which the filament could be subsequently drawn. Table 3 shows the increase in yarn productivity calculated from the Instron elongation at break as in Examples 1 and 2.

In addition, samples of the fused bottle yarn filaments were hot drawn in a standard manner using 90 qo hot pins and 18000 hot plates at a draw ratio as high as practical.

The draw ratio was increased stepwise by 0.1, and the maximum operable draw ratio was determined for each filament. The maximum draw ratios are shown in Table 3 along with the % increase in spinning productivity. 3%CL
The productivity increase calculated from the increase in maximum draw ratio for OTH compared to the control was approximately consistent with the productivity increase predicted by Instron elongation at break.

In Example 3 of Table 3, these evaluation values of productivity increase can be compared well with the results of Example 1 within the range of experimental error at winding speeds of 2 pieces/min and 4 pieces/min.

All of these evaluation values are positive, but they do not match well numerically. In the comparative example, AIk which is not an LC polymer
Addition of 3% athene did not increase the draw ratio that could be achieved even with the highest WUS, which resulted in some changes in birefringence and shrinkage.

In contrast, in Examples 3 and 4, both the LC polymers CLOTH and CO substantially increased productivity in addition to providing substantial changes in birefringence and shrinkage and thus WUS suppression. However, in these examples CLOT
H and CO had clearly different effects on modifying PET. Figures 1 and 2 show the shrinkage and birefringence data of Table 3 plotted against WUS. The 3% CO formulation showed almost 50% birefringence suppression.

Examples 5, 6 and 7 In the following experiments, three LC polymers and a conventional plasticizer for comparison were intimately mixed with the host polymer nylon 6,6.

The polymers used were as follows. A (Used in Example 6) Copoly(chloro-1,4-phenylene ethylenedioxy-4,4-dibenzoate/terephthalate) (CLO) made according to Example 3 of USP 3991031
TH).

It has an intrinsic viscosity of 1.07 d at 25 oo in a 0.5% solution of 30% trifluoroacetic acid and 70% dichloromethane.
l/g. This copolymer has a molecular weight of 215 to 2250
0, resulting in an anisotropic melt when observed on a Lejtz hot stage attached to a ratio itz SMPOL model deflection microscope. The melt viscosity was 50 Ns/m at 1 and 27,000 N/m. (Magazine: This was different from the CLOTH used in Examples 1, 2 and 3). B (Used in Example 7) USP416147
The 4-hydroxybenzoic acid/6-hydroxy 2-naphthoic acid copolymer (CO) prepared in Example V of 0.

This is a 0.1% solution of pentafluorophenol.
At 0q0, 5. had an intrinsic viscosity of 1 nog. This copolymer melted at about 26,000 ℃, resulting in an anisotropic melt. Melt viscosity 600N at 1 piN/force and 270℃
It was s/〆.

(Koto: This was different from the CO used in Example 4). C (Used in Example 5) Copolyethylene terephthalate/p,-oxybenzoate (X7G).

This is what W. J. Jackson and H. F. Kuh
Fuss, J. Poly. Sci. (Poly. Che
m. Edition), 2043, 14 (1976) and USP 3,778,410 and 3,084,805. The intrinsic viscosity is 25 for a 1% solution of dichloroacetic acid.
It was 0.34 dl/g at oC. This polymer is 18
At 800 it became a heterogeneous melt. The melt viscosity was 1 pN/m and 27,000, 220 Ns/m. D (
(Used in Comparative Examples) SANTICI Crime R: A solid sulfonamide plasticizer manufactured by Monsanto.

The above polymer was added to ICI SOS at the following concentration moment by moment.
Grade nylon 6,6 and diameter 1 with L/D ratio 30:1
．． PLAST with 5 inch nylon screw
Blended in an ON single screw extruder.

The screw rotates at 5pm, and the supply band is approximately 29,000mm.
, the barrel temperature from the feed zone to the end of the die is 29700, 298°C, 287°C for CLOTH and X7G! ,29
400 and 299℃, CO and SANTIC128
Slightly lower in R 28300, 29000, 28600
and 27,200. A 0.25 inch diameter lace was extruded through a take-off device into a water bath and then into a lace cutter. The average production rate was 123 evenings/minute. As a control, nylon 6 without polymer addition
, 6 was passed through an extruder.

A blend with SANT1CIZER was used as a comparative example.

Prior to blending, LC polymers CLOTH, CO and X70 were dried overnight in an open vacuum at 60-70 oo. Nylon 6,6 was also dried overnight in an open vacuum at 90:00. Batches of lk9 each were made and the first 200 batches were dumped to eliminate the residue from the previous batch. The resulting blend was threaded on a rod threading machine through a 15 mil spinneret hole without any air or steam tempering tubes.

The amount of yarn extruded was 34 evenings/hour/hole. The resulting filaments were wound at various WUS speeds ranging from 1 to 5 ships/min. In order to achieve good spinning technology for nylon 6,6, many difficulties had to be solved. 24,000 (1 minute) even though the nylon was pre-dried overnight.
The manufacture of candles in 1997 apparently caused a considerable reduction in molecular weight, as evidenced by the very high water content of the extrudates. Therefore, I decided to spin the chips directly, and as a result, I was able to spin the chips immediately, and the result was successful.
It has proven to be a time saver. As long as the paper yarn pack was flushed with polypropylene at the end of spinning, the paper yarn pack could be used many times (the residual nylon remaining in the yarn pack would decompose after the paper yarn was finished, leaving the spinning pack intact). ) could not be used again). Another difficulty arose because a steam steel machine was not used. Yarn in middle WU
When you wind up directly to the capstan with S, the yarn suddenly stretches during the thread and the centrifugal force causes it to become cuffed. He was thrown outward from the stun and became a makatoriki noh. Although this is not expected to occur at high speeds, LC polymers effectively reduce WUS, so it is essential to solve this problem. It has been found that this difficulty can be avoided if the spinning process is omitted and the nylon is delivered dry directly to the capstan. This means that the yarn cannot be wound back onto the bobbin and must be spooled for the next test. This precluded the final evaluation of hot stretching, which was possible for the polyethylene terephthalate of Example 3. On the other hand, there were some unexpectedly large effects.

The Instron test required dividing the skein into many parts and determining the weave of each part by weighing them individually. The weave used was 20 to 100 times the usual low yarn grade, but this was limited in consideration of the throughput/WUS. This led to excellent reproducibility in the Instron test by avoiding errors due to texture variations along the yarn. There was a concern that not applying moisture during spinning could result in unstable aging conditions and the birefringence of the nylon could gradually change over time.

However, at 3.6 tsumugi/min, the birefringence of a sample cut from the spun line above the temperer and immersed in Euparol on a slide rose to 75% of the package value in 3 minutes; Since it cleared within a few hours and amounted to only a few percent, it was excluded as having no experimental value.

The reason for using birefringence as a criterion for comparing the examples of this invention with the controls and comparative examples is because of the increase in birefringence after the paper threads, and this property is the reason why the LC polymer exhibits its maximum effect. This is difficult because the applied high WUS tends to become constant and the magnitude of change decreases by 4. However, for completeness of explanation, Figure 3 also includes the results obtained in Examples 6 and 7 and the control, as well as a graph of the birefringence versus WUS of the products obtained by the normal grade yarn method using a steam tempering machine. It is shown. This graph shows no significant difference between the LC polymer and control. However, the stress-strain curves were found to provide a satisfactory basis for comparing the Example products to the Control and Comparative Example products.

In general, the stress at constant elongation increases very uniformly, so the true stress at a fixed elongation of 50% provides a good basis for comparison between various products. Based on a specific stress-strain curve,
The effect of 6% CLOTH is illustrated and illustrated in FIG.

Using two types of controls, CLOTH, C○, X7
0 and SATICI cup R are shown in Table 4 and Figures 5 and 6.

For comparison, the curves shown in FIGS. 5 and 6 were used, all curves were standardized as equivalent low WUS, and the results are shown in FIG. SANTICIZER remaining on the fibers after grade yarn
Analysis of the amount revealed that the amount was 5.4%, and a small amount was lost during spinning. It was demonstrated that the cage value was reached.

It is known that dry nylon absorbs moisture from the air very quickly. Chappel et al., freshly graded yarn or dried nylon of diameter 90R reaches equilibrium moisture content after 3 hours and 80% of it when exposed to ambient air.
was found to be obtained after 1 hour [J. App
l. Chem, 14, 12 (1964)]. The diameter of the largest thread of this invention was only about 25 mm. To be absolutely sure, this invention uses a minimum elapsed time of 1 day after grade before testing, during which time the nylon
It was stored in a tempering laboratory at %RH and 700C. The final problem to be resolved was extrusion temperature.

As high a temperature as possible was necessary to reduce the pack pressure and ensure activation of the LC polymer in the thread. On the other hand, too high a temperature will decompose and degrade nylon and LC polymers. A temperature of 30°C was thus found to be a good compromise. Various properties, especially those related to WUS, were measured.

Nylon edge yarn boiling water shrinkage is extremely low Table 4 Note:
Calculated from the curves in Figures 5 and 6.

＊× Calculated from the curve in Figure 8.

It is clear that LC polymers become increasingly effective at higher WUS.

The effect of 6% CO in Figure 7 is particularly remarkable, with 5
It has decreased to over 0%. Table 5 shows the relative viscosity (RV) of the nylon 6,6 chips and various blends of fibers obtained therefrom.

In particular, this table demonstrates that the effect of the LC polymer addition is not due to nylon degradation, since the RV of the yarn containing the LC polymer is virtually the same as the control. Table 5 Another useful metric used for LC polymer blends is the Instron elongation at break.

The results obtained are shown in FIG. 8 and Table 4. To avoid confusion, the average elongation at break for the two controls is shown in FIG. This is because Table 4 shows that average elongation at break is not as sensitive a property as stress. The increase in elongation at break is of particular interest as it indicates the potential direct utility of this invention. The results of the Instron test can be translated into equivalent hot drawing behavior (there is no reason to think otherwise), and the potential increase in productivity is shown in FIG. However, since the control elongation at break was unreliable, the result of 5 pieces/min was removed. The elongation at break of the 3%X7G blend in FIG. 8 is lower than that of the 3% CLOTH blend, although both provide approximately the same WUS suppression in FIGS. This was expected since the X7G blend fibers have scattered flecks of X70 due to non-uniformity of the LC polymer in the blend. For this reason, X7G was removed from the productivity increase in Figure 9.
It should be noted that SATICI mottling R reduces the elongation at break in the comparative example.

[Brief explanation of drawings]

FIG. 1 is a graph showing the relationship between winding speed (WUS) and boiling water shrinkage. FIGS. 2 and 3 are graphs showing the relationship between WUS and birefringence. FIG. 4 is a stress-strain curve. 5 and 6 are graphs showing the relationship between WUS and stress at 50% elongation. Figure 7 shows WUS and equivalent low W
It is a graph showing the relationship with US. FIG. 8 is a graph showing the relationship between WUS and elongation at break. Figure 9 shows WU
It is a graph showing the relationship between S and productivity increase. Evening evening. 7
．． Hit 9.2. Hit. M. Appendix 9. j. Hit 9. Strike 9.5. Hit 9.6. Evening evening. 8. (Evening. Evening.

Claims (1)

[Scope of Claims] 1. A fiber-forming thermoplastic polymer selected from polyethylene terephthalate and polyhexamethylene adipamide, containing a small amount of polymer capable of forming an anisotropic melt in a temperature range capable of melt-spinning the thermoplastic polymer. and melt spinning both polymers together in the form of an intimate mixture at a winding speed greater than 1 km/min, and in the absence of the added polymer, by spinning at a lower winding speed. 1. A method for melt spinning the thermoplastic polymer, characterized in that it produces fibers having properties that the fibers have. 2. Claim 1, wherein the anisotropic melting temperature range of the added polymer and the spinnable temperature range of the fiber-forming polymer selected from polyethylene terephthalate and polyhexamethylene adipamide overlap by at least 5°C. The melt spinning method described in. 3. Melt spinning process according to claim 1 or 2, wherein the added polymer is present in the mixture in a concentration of 0.1 to 10 wt%. 4 The fiber-forming polymer is polyethylene terephthalate, and the added polymer is copoly(chloro-1,4-phenyleneethylenedioxy-4,4'-dibenzoate/terephthalate) or 6-polymer with a molar ratio of 60%/40%. Oxy-2
-Claim 1, 2 or 3 is a copolymer of a naphthoyl moiety and a p-oxybenzoyl moiety.
The melt spinning method described in section. 5 The fiber-forming polymer is polyhexamethylene adipamide, and the added polymer is copoly(chloro-1,4-phenyleneethylenedioxy-4,4'-dibenzoate/terephthalate), molar ratio 60%/ 40% 6-oxy-
Copolymer or copoly(ethylene terephthalate/p-
oxybenzoate) according to claim 1, 2 or 3.