JPH026871B2 - - Google Patents

Description

[Detailed description of the invention]

<Industrial Application Field> The present invention relates to a polybutylene terephthalate crimped yarn and a method for producing the same. <Prior art> Crimped yarns made of polyester, polyamide, etc. have traditionally been widely used in the production of bulky, stretchable woven and knitted fabrics, but in recent years there has been a strong demand for higher quality and lower prices for crimped yarns. . Therefore, there is a strong desire for a crimped yarn that has high elasticity and is free from trouble in the weaving and knitting fabric manufacturing process. For example, it is a crimped yarn that does not cause multifilament single yarn breakage or scum in the weaving or knitting fabric manufacturing process. These needs also apply to polyesters, especially polybutylene terephthalate crimped yarns. In other words, polybutylene terephthalate crimped yarn has excellent elasticity and color clarity that polyethylene terephthalate crimped yarn does not have, and excellent feel that polyamide crimped yarn does not have, so there is a strong desire to solve the above problems. There is. <Objective> Among the above-mentioned problems, the object of the present invention is to provide a polybutylene terephthalate crimped yarn and a method for producing the same, which do not cause scum to occur during the production of woven or knitted fabrics. <Solution> As a result of intensive studies by the present inventors to obtain a polybutylene terephthalate crimped yarn that does not generate scum during the production of woven or knitted fabrics, we found that scum was generated due to the pH of the oil agent attached to the polybutylene terephthalate crimped yarn. They discovered that the amount makes a big difference, and through further research, they arrived at the present invention. <Structure and operation> That is, the present invention provides (1) a polybutylene terephthalate to which an oil agent is attached in a range of 0.2 to 3.0% based on the yarn weight, and the pH of the oil agent attached to the yarn is 6.2 or more; Crimp and (2) Production of polybutylene terephthalate crimped yarn, characterized in that the pH of the oil emulsion applied during spinning is set to 7.5 or higher, and the oil emulsion is attached to the spun polybutylene terephthalate yarn, and then stretched and false-twisted. The main content is methods. In the present invention, it is necessary that the oil agent application rate to the polybutylene terephthalate crimped yarn be in the range of 0.2 to 3.0%. If it is less than 0.2%, the oil adhesion on the yarn will be uneven, the oil coating will become thin, and abnormal tension will occur during the production of woven or knitted fabrics.
Damage to the yarn and even scum will occur. On the other hand, if this adhesion rate exceeds 3.0%, oil scattering occurs due to the oil retention limit of the yarn, so it is necessary to keep it below 3.0%, more preferably below 2.5%. The most distinctive feature of the present invention is that the pH of the polybutylene terephthalate crimped thread-imparting oil is maintained at 6.2 or higher. This point will be explained in more detail with reference to the accompanying drawings. In Figure 1, the amount of scum generated decreases as the pH of the applied oil increases, but it decreases particularly significantly at pH 6.0 to 6.1, and the stable pH range that does not cause problems in use is 6.2.
More preferably, it is 6.3 or more. The reason why scum generation is drastically reduced by increasing the pH of the applied oil to 6.2 or higher is still not fully understood, but according to research by the present inventors, increasing the pH of the applied oil improves the smoothness of the main component of the oil. Improved compatibility of agents, emulsifiers, and antistatic agents in non-aqueous conditions has been confirmed. Therefore, it is presumed that by setting the pH to 6.2 or higher, the compatibility between the oil components on the polybutylene terephthalate crimped yarn is good, and thus the generation of scum is suppressed. On the other hand, the upper limit of the pH of the applied oil is not limited in terms of scum generation, but if it is too high, problems such as deterioration of polybutylene terephthalate or mold growth of the applied oil will occur, so it is at most 9.0.
More preferably, it is 8.0 or less. There are some things to keep in mind when setting the pH of the oil agent attached to the polybutylene terephthalate crimped yarn to 6.2 or higher, which is a feature of the present invention. The goal is to adjust the pH of the spinning oil emulsion to 7.5 or higher. Figure 2 shows the relationship between the PH of the spinning oil emulsion and the PH of the oil adhering to the yarn. There is a positive correlation between the PH of the spinning oil emulsion and the PH of the yarn oil, and in order to obtain a PH of 6.2 or higher for the oil attached to the yarn, the PH of the spinning oil emulsion must be 7.5 or higher. Polybutylene terephthalate as used in the present invention refers to polybutylene terephthalate containing 70% by weight or more, and 30% by weight or less of other polymers such as polyethylene terephthalate, polyamide,
It may contain a copolymer, a heat stabilizer, an antioxidant, a matting agent, etc. In order to maintain the oil application rate on the yarn within the range of 0.3 to 3.0%, an oil emulsion is added as a spinning oil after polybutylene terephthalate melt spinning and before winding.
The most common and easiest method is to apply it at a concentration of 0.3 to 3.0%, but a non-aqueous oil may also be used, and a step of applying a crimped yarn oil may also be used. In this case, there are no particular restrictions on the oil composition and oil components, and those commonly used in this field may be used. If an oil application process is used after crimping, the overall oil application rate on the yarn should be 0.3 to 3.0%,
Just adjust it so that the pH is 6.2 or higher. The manufacturing process of the polybutylene terephthalate crimped yarn of the present invention includes: A process in which spinning, drawing, and false twisting are independent processes A process in which spinning and drawing and false twisting are independent A process in which spinning and drawing and false twisting are independent Spinning and drawing false twisting Any process that makes processing continuous can be adopted, and an oil agent application process after false twisting may be added either singly or continuously. Here, the spinning process may be either a spinning process of a low-oriented undrawn yarn by taking off at a low speed, a spinning process of a highly oriented undrawn yarn by taking off at a high speed, or a so-called partially oriented yarn spinning process. Note that the stretch rate of the polybutylene terephthalate crimped yarn in the present invention is not particularly limited, and for applications that require high stretchability, crimped yarns with a high stretch rate may be used, while crimped yarns with low stretchability may be used. A crimped yarn with a low elasticity may be used. In the present invention, the oil adhesion rate, the PH of the adhering oil, the PH of the spinning oil emulsion, and the amount of scum generated are measured by the following methods. (a) Oil adhesion rate Extract the oil from 3 g of polybutylene terephthalate crimped yarn with cyclohexane for 30 minutes using a Soxhlet extraction group, evaporate the cyclohexane in the extract, measure the weight (W) of the remaining oil, and determine the oil adhesion. Calculate by ratio (%) = (W/3) x 100. (b) PH of attached oil agent 20g of polybutylene terephthalate crimped yarn
Extract the oil by stirring with g of distilled water at 40°C for 30 minutes, naturally cool the oil extract to 20°C, and measure with a Hitachi-Horiba M-7 PH meter. (c) PH of spinning oil emulsion Oil emulsion manufactured by Hitachi-Horiba at 20℃
Measure with M-7 type PH meter. (d) Amount of scum generated Polybutylene terephthalate crimped yarn at 20℃, 65℃
Supply the sample adjusted at %RH for 2 days with a tension of 0.5 g/
The same sample was run 5 times on a chromium matte guide with a diameter of 4 mm and a roughness of 5 ^seconds at a contact angle of 90 degrees and a take-up speed of 700 m/min for 120 minutes, and the amount of scum attached to the guide (unit: mg) was measured. Measure. [Example] Example 1 Titanium oxide 0.1% by weight with intrinsic viscosity [η] 0.88
The polybutylene terephthalate contained therein was melted at 265°C, discharged at a rate of 5.1 g/min using a spinneret with 6 holes of 0.3φ, and taken off at a take-up speed of 1000 m/min.After applying a spinning oil, the product was wound and unstretched. Got the thread. The spinning oil used at this time was an emulsion whose main components were a leveling agent, an emulsifier, and an antistatic agent (Table 2) with ion-exchanged water to a total concentration of 7.5%, and the pH of the emulsion was adjusted with caustic soda or lactic acid. It was used with various changes. The amount of spinning oil applied was adjusted so that the oil adhesion rate after crimping was 0.55 to 0.6%. Then, the undrawn yarn was drawn 2.3 times at a speed of 500 m/min, and the Shore hardness was continuously adjusted at a heater temperature of 190°C.
A 20 denier/6 filament crimped yarn was obtained by false twisting using a 93° urethane shaft circumscribed friction false twisting device. Table 1 shows the amount of scum generated in the obtained crimped yarn.

【table】

[Table] Table 2 Smoothing agent Isostearate ester of lauryl alcohol (4 moles of EO added)...70% by weight Emulsifier Nonyl phenyl (9 moles of EO added) ether
…10% by weight lauryl (EO 10 mole addition) ether
…10% by weight Antistatic agent Sodium metal salt of alkyl sulfate …5% by weight Metal soap …5% by weight Example 2 Crimped yarn test No. 2, 4, 5 obtained in Example 1,
A stocking knitting test was conducted using a KT-4 type stocking knitting machine manufactured by Nagata Kikai Co., Ltd. at 600 rpm. As a result, the crimped yarn according to the present invention (Test No.
5, 6, and 8) showed no scum adhering to the knitting needles even after continuous knitting for 24 hours, and the knitted fabrics did not have any cuts or cuts.
It was in good condition with no skipped stitches, step spots, warp lines, etc. On the other hand, with the crimped yarn other than the present invention (Test No. 2), scum adhesion to the knitting needles was observed after 6 hours, and at the same time, warp lines were generated in the knitted fabric. Further, in Test No. 4, the same problem as Test No. 2 occurred after 18 hours.

[Brief explanation of drawings]

Figure 1 is a graph showing the relationship between the attached oil PH and the amount of scum generated for polybutylene terephthalate crimped yarn, and Figure 2 is a graph showing the relationship between the PH of the spinning oil emulsion and the amount of scum produced.
It is a graph showing the relationship between and the adhering oil agent PH.

Claims (1)

[Scope of Claims] 1. A crimped polybutylene terephthalate yarn, characterized in that an oil agent is attached to the yarn in an amount of 0.2 to 3.0% based on the weight of the yarn, and the pH of the oil agent deposited on the yarn is 6.2 or more. 2. The polybutylene terephthalate crimped yarn according to claim 1, wherein the pH of the oil adhering to the yarn is 9.0 or less. 3 Production of polybutylene terephthalate crimped yarn, characterized in that the pH of the oil emulsion applied during spinning is set to 7.5 or higher, and 0.3 to 3.0% of the oil emulsion is applied to the spun polybutylene terephthalate yarn, and then stretched and false-twisted. Method.