CS273090B1 - Antistatic polyamide fibre - Google Patents

Abstract

The solution concerns antistatic treatment of polyamide fibres. The principle of the solution is the fact the fibre has a core-coating structure where the core is formed by polyamide and the coating by polyamide treated by 1 to 10 percent by weight of the modifier based on polyester ester amide. The weight ratio of the core and coating is 3 to 1 : 1.

Description

The invention relates to antistatically modified polyamide fibers.

One of the characteristics of synthetic fibers is their high electrical resistance and the associated tendency to electrostatic charge on their surface. Low electrical conductivity of the synthetic polymers at the same time prevents a rapid decrease in the charge formed. The influence of these negative properties can be reduced by chemical or chemical weight. physical modification of the polymer, in particular by increasing its electrical conductivity.

There are several ways of electrical conductivity of polyamide but also other synthetic fibers. These include:

- surface treatment of the fiber

adding antistatic additives to the polymer melt

- addition of plated or coated steel carbon fibers for synthetic fiber products (knitted fabrics, fabrics).

Low and high molecular weight substances such as esters and other fatty acid derivatives, metal oxides, benzene and phenyl sulphonates, modified polyglycols, polyether ureas, polyethylene oxide derivatives, organometallic compounds, etc. have been used as antistatic additives. These may also include a polyetheresteramide modifier, which is prepared by reacting polyethylene glycol, dicarboxylic acid and a catalyst with -caprolactam.

Regarding the permanence of the antistatic treatment of the fibers, the most suitable method of chemical modification, i.e. adding an antistatic modifier to the granulate, respectively; into the melt of the base polymer prior to the fiber preparation process. In some cases, the modifier is added already in the polymerization process of the base polymer.

The whole-mass modified antistatic polyamide fibers are characterized by good stability of the antistatic effect even after multiple washings. They were prepared using a polyetheresteramide modifier (AO 231 794).

Increasing the content of the modifier added to the fiber mass while improving its antistatic properties adversely affects the processing and physical-mechanical properties of the fiber.

These drawbacks are overcome by an antistatic polyamide fiber treated with a polyetheresteramide modifier, consisting essentially of a polyamide core and a sheath having a weight ratio of 3 to 1: 1, the sheath consisting of polyamide containing 1 to 10% by weight of the modifier .

Bicomponent fibers with a core shell structure were prepared on a spinning machine with two melt-dosing extruders and a common spinneret. The polymer streams are joined in the die channel space, the core / shell weight ratio being determined by the rate of polymer feed from the individual extruders to the spinneret. The prepared fiber is continuously drawn.

The core / shell immersion size affects the antistatic properties as well as the structure and ultimate physico-mechanical properties of the polyamide fiber. The presence of a dispersant has been shown to be important in terms of uniform placement of the modifier, which positively affects the physico-mechanical properties as well as the antistatic efficiency of the fiber. Sufficiently high antistatic efficacy after multiple washes while maintaining physico-mechanical properties was achieved with modified core-shell fibers with a J / P ratio of 1/1 to 3/1. At a lower relative content of the modified sheath, a fiber with an uneven cross-section is already formed, causing a deterioration in its physico-mechanical properties.

The core shell structure allows the base polymer to acquire new surface properties characteristic of the polymer that forms the sheath of the fiber. The core prepared from the base polymer retains the other floods through the properties of the modified fiber. The final properties of the fiber are influenced by the arrangement of the components and the shape of the core, which depend on the shape of the spinner, the composition of the spinning block and the selected fiber forming conditions. Another advantage is the lower consumption of the additive.

Example 1

A modified polyamide for fiber sheath application was prepared by remelting a mechanical polymer-antistatic modifier (polyetheresteramide, melting point = 198-204 c, MW = 1000-7000, acid number 11.67 mg KOH / g) dispersant (stearic acid monoglyceride) in a ratio of 96: 3: 1 in an extruder at 250 ° C. Modified polyamide granules were prepared by cutting the extruded string.

Polyamide fiber with a core-shell structure was prepared on a spinning machine with two melt-batch extruders and a common spinneret. The extruder 1 supplies the melt of unmodified polyamide 6 to the inner part of the spout (fiber core) through the extruder 2, the antistatic modified polyamide, which forms the sheath of the fiber, is fed to the outer annulus of the spout.

Fiber creature conditions:

Extruder 1 (core) temperature 245 ° C Extruder 2 (mantle) temperature 255 C Towing speed 400 m / min ¹ ' Debt rate. 1200 m.min ^-1 The drawing temperature 100 'c Weight core / sheath ratio 1/1

The fiber was continuously elongated at a draw ratio of 1: 3 to a unit fineness of 160 dtex. At the same time, under the same conditions, a reference fiber having the same density was prepared without the addition of a modifier.

The physico-mechanical properties of the modified polyamide did not change compared to the unmodified flood fiber. Knits were prepared from the fibers, which were subjected to a 10x wash cycle in washing solution Instr (4 g / l solution) at 40 ° C.

For dried and air-conditioned specimens, electrostatic properties were measured on a friction electrification apparatus STATE CHARGE PD-28 under the following conditions:

number of friction cycles 15 load of friction element 2 N distance of inductive probe 1. 10 ° C ^and temperature 25 ° C relative. humidity 65%

The maximum electrostatic pole intensity and the time course of electrostatic charge discharge on the surface of the article were evaluated. The measured values are shown in Tab. no. 1: Tab. no. 1- Electrostatic properties of PAD 6 fiber

Reference thread

Maximum power intensity state. pole, kV .cm ¹ 30.5

Electricity Intensity state. pole after 120 s discharge, kV. cm ¹ 28

Electricity Intensity state. pole after 300 s discharge, kV. cm '

Modified thread

18.4

0,6 a

CS 273 090 Bl

Example 2

A modified polyamide 6 containing 5 wt.% Was used in the outer layer (sheath) in the preparation of the bicomponent polyamide fiber. % antistatic modifier based on polyetheresteramide and 1 wt. a steraric acid monoglyceride dispersant. Modified fiber (core - unmodified PAD 6, sheath modified PAD 6) with core / plastic ratio = 1/1, as well as the reference unmodified polyamide fiber were prepared and evaluated as in Example S. 1. Measured values of electrostatic properties are shown in Tab. . no.

Second

Tab. no. 2 - Electrostatic properties of PAD 6 fiber

References fiber modified fiber Maximum power intensity state. pole, kV. cm ¹ 30 13 Electricity Intensity state. pole after 120 s discharge, kV. cm ¹ 28 0.7 Electricity Intensity state. pole after 300 s discharge, kV. cm ^-1 25 0

Example 3.

A polyamide granulate containing 5% by weight of polyetheresteramide (modifier) and 1% of polyethylene glycol with a molecular weight of 6000 (dispersant) was used to prepare the modified polyamide into the bicomponent fiber sheath. A modified fiber with a core / sheath weight ratio of 1/1 and a reference polyamide fiber was prepared and evaluated as in example no. 1. The measured values are given in Tab. no. Third

Tab. no. 3 - Electrostatic properties of PAD 6 fibers

References fiber modified . fiber Maximum power intensity state. pole, kV. cm ' ¹ 30 15 Electricity Intensity state. pole after 120 s discharge, kV. cm ' ¹ 28 1.7 Electricity Intensity state. pole after 300 s discharge, kV. cm ” ¹ 25 0

Example 4.

Both the reference and the modified polyamide fibers were prepared as in Example no. 1, except that the core / sheath weight ratio was changed to 3: 1. The fiber was processed into knitted fabrics and evaluated as in Example no. 1. Measured values of electrostatic properties of fibers with lower content of modified layer are given in Tab. no. 4th

Tab. no. 4 - electrostatic properties of PAD 6 fibers References fiber modified fiber Max. el. state. pole, kV. cm ' ¹ 30 20 Electricity Intensity state. pole after 120 s discharge, kV. cm ” ¹ 28 11 Electricity Intensity state. pole after 300 s discharge, kV. cm ^-1 25 8

CS 273 090 B1 4

It is evident from the examples that the polyetherestramide-based modifier, in the presence of the dispersants used, will act as an effective antistatic prostired agent even when applied only to the surface layer of the fiber. The high antistatic effect is maintained even after multiple washings, while the relatively low modifier content in the fiber mass, while lowering its consumption, less affects the original chemical and physico-mechanical properties of the unmodified polyamide fiber.

Claims (1)

OBJECT OF THE INVENTION An antistatic polyamide fiber modified with a polyetheresteramide base, characterized in that it consists of a polyamide core and a sheath having a weight ratio of 3 to 1: 1, the sheath comprising polyamide β containing 1 to 10% by weight of the modifier.