JPH01229809A - Production of polyphenylene sulfide fiber - Google Patents

Abstract

PURPOSE:To obtain the subject fiber having excellent physical properties without causing yarn breakage and fluffing on an industrial scale, by melt spinning a polyphenylene sulfide, drawing and heat-treating the resultant fiber under specific drawing conditions. CONSTITUTION:A polyphenylene sulfide is melt spun, initially drawn in the first stage with a heating unit (HR1) at 85-110 deg.C surface temperature so as to provide <=45% breaking elongation of the fiber after drawing. The drawn fiber is then heat-set with a heating unit (HR2) at 100-140 deg.C surface temperature at feeding rate of 1.0-0.90 and a constant length or under relaxed conditions. The heat-set fibers are subsequently heat-set with a heating unit (HR3) at a surface temperature of >=150 deg.C-<= the melting point at a feeding rate of 1.0-0.95 and a constant length or under relaxing conditions to afford the aimed fiber.

Description

Detailed Description of the Invention <Industrial Application Field> The present invention relates to a method for producing polyphenylene sulfide fibers having excellent fiber properties, and more specifically, after melt-spinning polyphenylene sulfide fibers, drawing and heat treatment are performed. When you do this, break the thread.

The present invention relates to a drawing-heat treatment method that provides good fiber properties under a stable process in which fuzz generation is minimized.

<Prior art> Polyphenylene sulfide is a highly crystalline thermoplastic heat-resistant polymer, so it has excellent heat resistance and drug resistance! It is expected to be an important fiber. Regarding the method of fiberization, Japanese Patent Publication No. 52-30309 discloses a method in which the polymer is precured to increase its viscosity, then melt-spun, and then the spun yarn is drawn in the cold.
The publication describes that when drawing in two or more stages after melt spinning,
A method is disclosed in which the second and subsequent stages are stretched at a much higher temperature than the first stage, which employs the same multi-stage stretching technology for polyethylene terephthalate, nylon 6 or 66, or the like. The present inventors also tried these methods, but these methods simply applied the stretching method conventionally used for polyester fibers and nylon m-fibers without paying attention to the characteristics of polyphenylene sulfide. It was found that because the film was too thin, thread breakage and fluffing occurred frequently during drawing, making stable industrial production impossible.

<Object of the Invention> Therefore, an object of the present invention is to provide a method for industrially stably stretching and heat treating polyphenylene sulfide fibers having good heat resistance, chemical resistance, and mechanical properties, and in particular, to provide a method for drawing and heat treating polyphenylene sulfide fibers having good heat resistance, chemical resistance, and mechanical properties. Standing, single thread breaks.

The object of the present invention is to provide a drawing-heat treatment method that can minimize yarn breakage.

<Structure and operation of the invention> As a result of intensive research aimed at achieving the above object, the present inventors have found that the drawing and heat setting of polyphenylene sulfide fibers, which have completely different physical properties from polyester and polyamide fibers, are as follows. The drawing process is carried out in one stage, and the subsequent heat setting process is carried out in at least two stages.In this case, the elongation of the drawn yarn obtained in the first stage drawing, and how to raise the heat setting temperature are critical to preventing fluff and yarn breakage. It was discovered that it was working.

Thus, according to the present invention, after melt-spinning polyphenylene sulfide, the method for producing polyphenylene sulfide fiber is characterized by subjecting it to a stretching heat treatment under the following stretching conditions.
After stretching using a heating element of 10℃ or less! One-stage stretching is performed so that the elongation at break of aIfI is 45% or less.

■ The surface temperature of the stretched am obtained in ■ is 100℃ or higher.
Constant length or relaxation heat setting is performed at a supply rate of 1.0 times to 0.90 times using a heating element of 40° C. or lower.

■ Heat set it obtained with ■! further heat the ill by 1.0 times to 0 using a heating element with a surface temperature of 150°C or higher and lower than the melting point.
．． Constant length or relaxation heat setting is performed at a feed rate of 90 times.

is provided.

To explain the present invention in more detail, first of all, the polyphenylene sulfide used in the present invention has 90% or more of its constituent units as p-phenylene sulfide, and particularly has a shear rate (shear rate) of 320° C. is 10
00/ Melt viscosity at 5eC is 800 bois or more1
Polyphenylene sulfide having 300 voids or less is preferred. After melt-spinning such a polymer and attaching an oil agent, it is subjected to stretching heat setting in a separate stretching or direct stretching process, and the present invention is characterized by the stretching heat treatment conditions.

This point will be explained below with reference to the drawings.

FIG. 1 is another drawing process diagram showing one embodiment of the drawing method of the present invention. The yarn wound after spinning is the pull-out roller FR.
and then the surface temperature is 85℃~110℃
In the heating diagram (hot roller)
It is wound 0 turns and preheated. At this time, FR and HR+
In order to eliminate yarn slack, the normal FR circumferential speed is H.
Increase the peripheral speed of R+ by 0.5 to 1%. Stretching roller D
R+ performs the first drawing between HR+ and DR+. The stretching ratio at this time is selected according to the elongation of the yarn (2) so that the elongation at break of the yarn (drawn fiber) exiting the DR+ is 45% or less, and the surface temperature of the HR+ is within the above temperature range. A stretching point is set on the exit surface of the HR+. The next heating element 11R2 is used for presetting (shown as a roller in the figure) and is heated to 100°C to 140°C. At this time, it is necessary to set the supply rate between DR+ and HR2 to 1.0 to 0.9 times, and to perform heat setting in a relaxed state within 10% of the fixed length. Therefore, it is normal that the next take-up roller DRz has the same speed as HR2, that is, a constant length, but the feed rate should be less than 1.0 times to 0.9 times between DR+ and DR2. You may relax for HR2. Furthermore, heating element HR3 (shown as a roller in the figure) is heated to a surface temperature of 150°C or higher and lower than the melting point of polyphenylene sulfide, and
The fibers are heat set under a feed rate of 1.0-0.9 and then taken off by the final take-off roller DR3. At this time too, D
R3 is adjusted so that a supply rate of 1.0 to 069 times that of DR2 can be obtained, and HR3 is adjusted so that the relaxation rate of DR2 and DR3 is in the range of 0 to 10%.

The first important condition in these series of drawing steps is to give the fiber after drawing an elongation of 45% or less by drawing between HR+ and DR+. If this elongation exceeds 45%, the yarn will wind around the hot roller of HRa frequently, leading to fluff and yarn breakage.

In addition, if the elongation at this time is excessively stretched so that the elongation is less than 15%, there will be frequent occurrences of wrap wrapping on HR+, DR+, or HR2, fuzz, and yarn breakage. Therefore, the elongation at break of the fibers exiting OR+ is in the range of 15% to 45%, more preferably 20% to
It is better to set it to 35%. On the other hand, it is important to maintain the temperature of the next preheat setting roller HR2 in the range of 100°C to 140°C. If this temperature exceeds 140℃ (i.e., if the material is suddenly placed in a high-temperature heat setting roller of 140℃ or higher after stretching, as with ordinary polyester or nylon), single yarn breakage and yarn breakage will occur frequently, resulting in stable and good physical properties. fiber cannot be obtained. In particular, if the set temperature at this time is 150° C. or higher, this tendency becomes noticeable and stable stretching cannot be expected. Therefore, the temperature of this preheat set is extremely important, preferably 110°C.
Maintained at ~130°C. By performing this preliminary setting, it is possible to reduce single yarn breakage and yarn breakage in the subsequent HRa process. This phenomenon is considered to be unique to polyphenylene sulfide. In this regard, in JP-A No. 57-143518, similar to the drawing method for polyester fibers, especially sewing threads and tire cords, the first stage drawing ratio is set to be equal to or higher than the natural drawing ratio, and the second stage is set to 1 of the full stage drawing ratio.
．． It has been shown that stretching is performed at a stretching ratio of 0 to 2 times and at a temperature much higher than the stretching temperature for one-stage stretching. However, in this type of two-stage stretching, fluff and yarn breakage actually occur frequently. This is because polyphenylene sulfide itself is stretched and crystallized very quickly, so the two-stage stretching results in a crystallized stretching state, resulting in fluff.

It is thought that thread breakage occurs frequently.

Finally, the final heat setting temperature of the present invention varies depending on the required characteristics of the final drawn yarn; C is suitable. The higher the final heat setting temperature is, the more likely the HRa or DRa roller is to wrap.

Unlike ordinary polyester and nylon fibers, polyphenylene sulfide fibers have the characteristic that fluff and yarn breakage are likely to occur during the final heat treatment if the first stage draw ratio, and therefore the degree of orientation of the fibers entering the final heat treatment process, is low. This is different from conventional thermoplastic fibers.

<Other Embodiments of the Invention> Although FIG. 1 shows the principle drawing process of the present invention, the process shown in FIG. 2 is most suitable for carrying out the present invention more realistically. In FIG. 2, FR and HR+ are the same as in FIG. 1, but between HR+ and HR2, the elongation of the drawn fiber on HRZ is 45% or less. In this case, its surface temperature is 85℃~110℃, usually 1
00℃ is preferable, and HR2 has a surface temperature of 10℃.
The temperature is 0°C to 140°C, preferably around 120°C. The following HR30-Ra has a surface temperature of 150°C or higher and a melting point (29
0°C) or lower, preferably 190°C to 220°C.

Further, heat setting is performed at a feeding rate of 1.0 to 0.9 times between HR2 and HRa, that is, a relaxation rate of 0 to 10%, preferably a relaxation rate of 0 to 3%. And the final take-up roller DR
3, it is taken up with a relaxation rate of 0 to 10%, preferably 2 to 5%, with respect to HRa, and wound on a W winder.

In addition, in the above process, hot rollers of HR2 and HRa that have a satin finish are more likely to have less fluff and breakage of single filaments than those with a chrome mirror surface, and stable stretching is possible.

On the other hand, in Fig. 3, the principle is the same as in Fig. 1, but a hot bin P is provided in place of HR+, a hot plate HP+ is provided in place of IR2, and a hot plate HP2 is provided in place of HRa. Give an example.

<Effects of the Invention> According to the present invention, polyphenylene sulfide, which has a draw heat setting behavior different from that of conventional polyesters and polyamides, can be drawn and heat set while preventing the occurrence of yarn breakage and fuzz. Therefore, drawn fibers with good physical properties can be provided on an industrial scale.

<Example> Polyphenylene sulfide having a melt viscosity (M, V) of 1100 voids measured at a melting temperature of 320°C and a shear rate of 1000/sec was melted at a temperature of 335°C in an extruder type extrusion chamber. After discharging the material at a rate of 35 g/min from a spinneret having 48 pores with a diameter of 0.30 ttus and cooling and solidifying it in air, an oil agent was applied and the spinning winding speed was 70.
An undrawn yarn was obtained by winding at 0 TrL/min. The undrawn yarn had a strength of 1.059/de, an elongation of 410%, and a natural draw ratio of 150%.

This undrawn yarn was drawn using the drawing apparatus shown in FIG. 2 under the drawing conditions shown in Table 1. At this time, the stretching ratio between RF and 1''R1 is 1
．． It was given a British rating of 01.

In Table 1, the first draw ratio is between FIR+ and HR2.
The second draw ratio (supply rate) is the draw ratio between HR2 and HRl, the third draw ratio (supply rate) is the draw ratio between HRl and DR3, and the total draw ratio is the first draw ratio, the second draw ratio, and the third draw ratio. It is multiplied by the stretching ratio.

The elongation of the fiber after the first drawing is the elongation at break of the fiber immediately after exiting HR2. Stretchability evaluation is performed by passing the yarn through a stretching machine and winding it up with a winder, and if the yarn is wrapped around each roller or breaks within 5 minutes, it is marked with an X. Those in which winding or yarn breakage occurred over time are indicated by △, and those which could be stretched for more than 30 minutes without any problems are indicated by Q.

As can be seen from this table, in the case of the present invention □JC12-4,
Demon 7-9. Nα11-13), and extremely good stretchability. On the other hand, comparative examples are as follows.

In Nα1, since the HRl was 85° C. or lower and the stretching temperature was insufficient, yarn breakage occurred immediately and processing up to the final step was not possible. In addition, in Nα5, HRl was as high as 115° C., contrary to Nα1, so the yarn swayed significantly on HRl, and the fiber not only could not run stably, but also broke easily. In order 6, after the first stretching! Since the elongation of the i-fiber was high, when it was threaded onto a 1" R3 heat setting roller, it immediately wound around the HR30 roller and broke.

For NQ10, the preheat set roller temperature is 100℃.
Because the thread was so low, it was wrapped around HR30-Lar like thread 6 and broke. On the contrary, at Nα14, the yarn suddenly entered 150° C. (HR2) without preheating, so winding and breakage occurred on this HRzO-sea. NQ15 to 17 are essentially two-stage drawing methods, and the yarn entering the HRl is treated at high temperature without being preheated, so it is wound around the HR30-lar and broken. For Nα18, the conditions are the same except that the order 17 and HR3 temperatures are low at 130°C, but in this case, although the stretchability is good, the HRl is low at 130°C, so there is no heat setting effect, and the characteristics of polyphenylene sulfide. Thermal stability.

In terms of heat resistance, the thermal shrinkage rate was high, and it was difficult to use it for industrial purposes in this state.

Similarly to Nα18, NQ19 had a high heat shrinkage rate due to its low R3 of 140°C and was difficult to use, but its stretchability itself was good. ■20 to 23 are examples of the present invention (HR
l of 150° C. or higher), the resulting yarn had a heat shrinkage rate of 20% or lower under free shrinkage at 180° C., and was of practical use. In addition, all the mechanical properties were excellent, with a strength of 4.0 g/de or more. Furthermore, the elongation of the yarn of the present invention is 23% ~
It was 38%. In the present invention, the total stretching ratio of 3.6 and 24 not only shows excellent properties with a strength of 6.29/da, an elongation of 16%, and a dry heat shrinkage rate of 9.1%. The stretching process was also stable.

Comparative Example Stretching was carried out according to Examples 1 and 2 of JP-A-57-143518.

The undrawn yarn used in the above example was stretched to 2.8 times in the first stage using l-I R at 100°C, and stretched to 1.25 times on a hot plate at 180°C in the second stage, and then completely stretched. The strength is 3.2 when the magnification is set to 3.5 and there is no subsequent setting.
g/da, elongation is 28%, but dry heat shrinkage rate is 150℃
x 20% or more in 30 minutes, which is a practical problem, and the strength is also low at 3.2 g/de. Also, there was a lot of lapping on the final cold IJ'l take-up roller.

In addition, the plate was stretched 3.5 times at 100°C in the first stage to form a plate 25
When the yarn was set at 0° C. and set at 1.0× constant length, the take-up roller frequently lapped, and the yarn broke after 1 minute.

Furthermore, the stretching ratio of the first stage was increased to 2.8 times, and the stretching ratio of the second stage was increased to 1.25.
When the yarn was stretched at a temperature of 1 to 250° C. and wound up with a take-off roller, lapping occurred on the take-up roller, and the yarn could not be taken up and was immediately broken.

[Brief explanation of the drawing]

1 to 3 are route diagrams showing the stretching heat setting process of the present invention. ■...undrawn yarn, FR...pull roller. HRl, HRz, HRl...-heating roller)
. DR+...first stretching roller. DR2...Take-up roller. P...Heating bottle. HRl, HRz... Heating body (plate) patent applicant
Teijin Ltd. Representative
Patent attorney former 1) Jun k'J -””':
■ W Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] A method for producing polyphenylene sulfide fiber, which comprises melt-spinning polyphenylene sulfide and then subjecting it to drawing heat treatment under the following drawing conditions. (1) Using a heating element with a surface temperature of 85° C. or higher and 110° C. or lower, single-stage stretching is performed so that the elongation at break of the fiber after stretching is 45% or lower. (2) The surface temperature of the drawn fiber obtained in (1) is 100℃.
1.0 times to 0.90 using a heating element of 140℃ or less
Perform constant length or relaxation heat setting at twice the supply rate. (3) The heat-set fiber obtained in (2) is further heated to a temperature of 1.0 to 0.0 times using a heating body whose surface temperature is 150°C or higher and lower than the melting point.
A constant length or relaxation heat set is performed at a feed rate of 95 times.