Claims
- 1. A process for producing a fiber not undergoing false twisting and consisting essentially of polyethylene terephthalate capable of being dyed under normal pressure and having an initial modulus at 30.degree. C. of about 55 g/d to about 130 g/d, a relationship between a peak temperature (T.sub.max (.degree.C.)) at the peak of a dynamic mechanical loss tangent (tan .delta.) measured with a frequency of 110 Hz and a peak value of the dynamic mechanical loss tangent ((tan .delta.).sub.max) represented by the formula:
- (tan .delta.).sub.max .gtoreq.1.times.10.sup.-2 (T.sub.max -105)
- and a (tan .delta.).sub.max of about 0.14 to about 0.30, a dynamic mechanical loss tangent at 220.degree. C. (tan .delta..sub.220) of at most about 0.055, and a T.sub.max (.degree.C.) of at most about 105.degree. C., which comprises subjecting a polyethylene terephthalate fiber obtained at a spinning speed of at least about 4000 m/min. to heat treatment at a temperature ranging from a temperature at which a dynamic modulus (E') of the fiber deviates from a tangent line at 180.degree. C. of a logarithm of the E' of the fiber-temperature curve (T.sub.min) plus 10.degree. C. to a temperature of completion of melting (T.sub.m.spsb.3) at a melting curve of the fiber measured by a differential scanning calorimeter (DSC) plus 10.degree. C.
- 2. The process according to claim 1, wherein the heat treatment is conducted at an extension ratio of from about -20% to about +5%.
- 3. The process according to claim 1, wherein the fiber spun is continuously subjected to heat treatment at a temperature higher than T.sub.min +20.degree. C. in the spinning step without winding.
- 4. The process according to claim 2, wherein the heat treatment is conducted at an extension ratio of from about -5% to about 0%.
- 5. The process according to claim 1, wherein the heat treatment temperature is at least about 235.degree. C.
- 6. The process according to claim 1, wherein the spinning speed is about 6000 m/min. to about 9000 m/min.
- 7. The process according to claim 1, wherein the spinning speed is about 8000 m/min. to about 9000 m/min.
- 8. The process according to claim 1, wherein the heat treatment period of time is at most about 10 seconds.
- 9. The process according to claim 1, wherein the fiber spun is subjected to heat treatment in a wet heat atmosphere at a temperature of at most 240.degree. C.
- 10. The process according to claim 9, wherein the wet heat atmosphere is superheated steam.
- 11. The process according to claim 10, wherein the polyethylene terephthalate fiber obtained at a spinning speed of about 6000 m/min. to about 9000 m/min. is subjected to heat treatment in a wet heat atmosphere at a temperature of at most about 235.degree. C.
- 12. The process according to claim 9, wherein the polyethylene terephthalate fiber is spun at a spinning speed of about 8000 m/min. to about 9000 m/min., wound and subsequently subjected to heat treatment in a wet heat atmosphere at a temperature of at most 240.degree. C.
- 13. The process according to claim 9, wherein the wet heat treatment is conducted at an extension ratio of about -20% to about +5%.
- 14. The process according to claim 13, wherein the extension ratio is about -5% to about 0%.
- 15. The process according to claim 3, wherein the heat treatment is conducted at an extension ratio of from about -5% to about 0%.
Priority Claims (4)
Number |
Date |
Country |
Kind |
56-46407 |
Mar 1981 |
JPX |
|
56-46408 |
Mar 1981 |
JPX |
|
56-71358 |
May 1981 |
JPX |
|
56-71360 |
May 1981 |
JPX |
|
Parent Case Info
This is a division of application Ser. No. 363,628, filed on Mar. 30, 1982, now U.S. Pat. No. 4,426,516.
US Referenced Citations (7)
Divisions (1)
|
Number |
Date |
Country |
Parent |
363628 |
Mar 1982 |
|