Polyamide 46 multifilament

Patent metadata

Field	Value
Publication number	US-12584248-B2
Application number	US-202117799153-A
Country	US
Kind code	B2
Filing date	Mar 9, 2021
Priority date	Mar 13, 2020
Publication date	Mar 24, 2026
Grant date	Mar 24, 2026

Abstract

A polyamide 46 multifilament has a strength of 6.0 to 9.0 cN/dtex and an elongation at break of 15% to 30%, an elongation rate (E′10) of less than 2.5% after heat treatment at 120° C. for 24 hours and subsequent stretching performed 10 times in a room temperature environment, and the difference (E′10−E′1) between the elongation rate (E′1) of the heat-treated fiber measured after stretching it once in a room temperature environment and its elongation rate (E′10) measured after stretching it ten times in a room temperature environment is less than 0.60%.

First claim

The invention claimed is:

1 . A method for producing a polyamide 46 multifilament having a total fineness of 300 to 2,300 dtex, a strength of 7.0 to 7.6 cN/dtex and an elongation at break of 18% to 30%, a heat shrinkage rate at 120° C. of 0.5% to 2.0%, an elongation rate (E′10) of less than 2.5% after heat treatment at 120° C. for 24 hours and subsequent stretching performed 10 times in a room temperature environment, and a difference (E′10−E′1) between the elongation rate (E′1) of the heat-treated fiber measured after stretching once in a room temperature environment and the elongation rate (E′10) measured after stretching ten times in a room temperature environment is less than 0.60%, wherein the polyamide 46 accounts for 98% by mass or more of the total mass of the polyamide resin excluding the mass of the additives and has a sulfuric acid relative viscosity of 3.0 to 5.0; the method comprising:
melt-spinning polyamide 46, wherein melting of polyamide 46 in the melt-spinning step is performed in a vacuum, and subjecting a resulting undrawn yarn to multi-step drawing, wherein the multi-step drawing contains at least a first step drawing and a final step drawing, with the final step drawing being performed to a draw ratio of 1.00 to 1.10.

Assignees

• Toray Industries

Inventors

• Kamijo Taichi
• Shigeno Hisao
• Minai Kazushi

Classifications

• D10B2401/04

  Heat-responsive characteristics · CPC title

• D10B2331/02

  polyamides (D10B2331/08 takes precedence) · CPC title

• D02J1/22

  Stretching or tensioning, shrinking or relaxing, e.g. by use of overfeed and underfeed apparatus, or preventing stretch (stretch spinning D01D5/12) · CPC title

• D01D5/12

  Stretch-spinning methods ({D01D5/098 takes precedence} finishing by stretching D02J1/22) · CPC title

• D02J1/228

  Stretching in two or more steps, with or without intermediate steps · CPC title