JPH04185764A - Deodorant fiber and its production - Google Patents

Abstract

PURPOSE:To obtain a flame-retardant deodorant fiber having a tensile strength and LOI higher than respective specific levels by introducing a specific amount of copper-ion crosslinked carboxyl group into a residual nitrile group of a crosslinked acrylic fiber having a specific ratio of nitrogen content increment and introducing an amide group into the remaining part of the nitrile group. CONSTITUTION:The objective fiber having a tensile strength of >=1g/d and a limiting oxygen index of >=30 can be produced by hydrolyzing an acrylic fiber crosslinked with hydrazine to adjust a nitrogen content increase to 1.0-8.0wt.%, introducing 0.5-4.5mmol/g of carboxyl group crosslinked with copper ion into a part of the residual nitrile group and introducing an amide group into the remaining part of the nitrile group.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a deodorizing fiber that has a high degree of flame retardancy and has practical performance that can withstand processing such as carting, and a method for producing the same.

(Prior Art) Many methods have been proposed to obtain deodorant fibers, one of which is the use of substances with deodorizing properties, such as metal phthalocyanine derivatives, ferrous sulfate/L-ascorbic acid. There is a method of attaching and fixing plant extracts such as flavonoids to the fiber surface, but this method generally has various drawbacks such as durability, change in texture, and flammability.

In addition, as another method, as shown in JP-A-63-214261, a fiber made by applying a transition metal to acrylonitrile fiber having a carboxyl group has been proposed, but it is not deodorizing and flame retardant. Some have the disadvantage of producing toxic gases when burned.

Other methods include activated carbon I# fibers obtained by carbonizing acrylic fibers and pitch fibers, but these are expensive. On the other hand, for flame-retardant fibers, for example, post-processing methods in which flame retardants such as phosphorus compounds and halogen compounds are attached and fixed on the fiber surface, and polymers made by copolymerizing vinyl halide and vinylidene halide monomers are used. There are methods for forming fibers, but the former generally has drawbacks such as durability, change in texture, flame retardant itself and toxicity during combustion, and the latter requires the use of halogen monomers to achieve high flame retardancy. The essential drawback is that it requires copolymerization of large amounts of polymers, resulting in the generation of toxic gases during combustion.

(Problems to be Solved by the Invention) The objects of the present invention are to provide the above-mentioned durability, no generation of toxic gas during combustion, high flame retardancy, and practical performance that can withstand processing such as hanging on a cart. The purpose is to propose deodorizing fibers with the following properties.

(Means for Solving the Problems) The above-mentioned object of the present invention is to provide a crosslinked acrylic fiber whose nitrogen content increases by 1.0 to 8.0% by weight due to hydrazine crosslinking, which 0.5 to 4.5 mmol/g of carboxyl groups ionically crosslinked with copper ions are introduced into the remaining part, and amide groups are introduced into the remaining part.
This is achieved by the flame-retardant deodorizing at-navy blue having a tensile strength of 1 g/d or more and a limiting oxygen index of 30 or more, and the manufacturing method according to the second claim.

The starting acrylic fiber is a fiber formed from an A, N-based polymer containing 40% by weight or more, preferably 50% by weight or more of acrylonitrile (hereinafter referred to as AN),
It can be in any form such as staple fiber, tow, yarn, knitted fabric, non-woven fabric, etc. Also, it can be used as a product in the middle of the manufacturing process or as a waste! ! ! I don't really care. The AN-based polymer may be an AN homopolymer or a copolymer of AN and other monomers, and other monomers include vinyl halides and vinylidene halides; (meth)acrylic esters; methallyl. Examples include sulfonic acid-containing monomers and their salts such as sulfonic acid and p-styrene sulfonic acid; carboxylic acid-containing monomers and their salts such as (meth)acrylic acid and itaconic acid; other monomers such as acrylamide, styrene, and vinyl acetate. .

A method for introducing hydrazine crosslinking into acrylic fibers can be adopted as long as the increase in nitrogen content can be adjusted to 1.0 to 8.0% by weight;
A method of treatment at a temperature of 50 to 120°C for 1 to 5 hours is industrially preferable. Here, the increase in nitrogen content refers to the nitrogen content of the raw material acrylic fiber and the W of the hydrazine crosslinked acrylic fiber.
Note that if the increase in nitrogen content is less than the lower limit above, it will not be possible to obtain a fiber with practically satisfactory physical properties, and if it exceeds the upper limit, it will have high flame retardant properties. Examples of the hydrazine used here that cannot produce fibers having both deodorizing properties include hydrazine hydrate, hydrazine sulfate, hydrazine hydrochloride, hydrazine nitrate, and hydrazine bromate.

In addition, by the hydrolysis reaction, the remaining nitrile group without being crosslinked with hydrazine is substantially eliminated, and 0.5 to 4
．． 5 mmol/g, preferably 1.0-3.5 mm
A method for introducing an amide group into the carboxyl group and the remainder of ol/g is impregnation with a basic aqueous solution such as an alkali metal hydroxide or ammonia, or an aqueous solution of a mineral acid such as nitric acid, sulfuric acid, or hydrochloric acid, or such aqueous solution. An example of this method is to heat-treat the raw material fibers while being immersed therein. Note that the hydrolysis reaction can also be carried out simultaneously with the introduction of the crosslinking bond.

In addition, if the carboxyl group is less than the above lower limit, it will not be possible to produce Ik that has both high flame retardancy and deodorizing performance, and if it exceeds the upper limit, the fiber will not have physical properties that are practically satisfactory. I can't get it.

As for the ionic crosslinking method, it is preferable to treat with a 1 to 20% by weight aqueous solution of an inorganic salt such as copper sulfate, copper nitrate, steel chloride, copper hydroxide, or an organic salt such as copper acetate at a temperature of 10 to 100°C. In addition, the amount of copper ions introduced is 0.5 to 4.5 meq/g, preferably 1.0 to 3 meq/g, in order to achieve the purpose of the present invention.
．． It is desirable to be within the range of 5+neq/g.

In this way, the tensile strength is Ig/d or more, preferably 1.5 g/d or more, and the limiting oxygen index (LOI) is 30 or more, preferably 32 or more, and has excellent absorption performance for malodorous substances,
Moreover, it is possible to provide a flame-retardant deodorizing fiber that does not generate toxic gas when burned.

It should be noted that the method of filling acrylic fibers into a container equipped with a pump circulation system and sequentially performing the above-mentioned cross-linking introduction, hydrolysis reaction, and formation of copper ion cross-links is not suitable for equipment, safety, Desirable from various points such as homogeneous reactivity. A typical example of such a device (vessel equipped with a pump circulation system) is an Obermeyer dyeing machine.

In addition, in order to maintain fiber physical properties that do not cause any practical problems, introduce a predetermined amount of carboxyl groups and copper ion crosslinks, and provide fibers that have both a high degree of flame retardancy and deodorizing properties, the following characteristics must be met. Acrylic system ready for departure! It is desirable to use 1' fiber.

That is, the AN polymer molecules forming the fibers are sufficiently oriented and the recongoulet (hereinafter referred to as CR) dichroic ratio is 0.
．． It is desirable to use acrylic fibers with a fiber density of 4 or more, more preferably 0.5 or more. Note that the CR dichroism ratio is determined according to the method described in Kobunshi Kagaku 23 (252) 193 (1966).

Note that there are no limitations to the method for producing such acrylic fibers.
As long as the above CR dichroic ratio is satisfied, known means can be used as appropriate, but among them, the total stretching ratio is 6 times or more,
Desired acrylic fibers can be produced industrially advantageously by employing means to preferably increase the shrinkage rate to 8 times or more and to reduce the shrinkage rate in the process to 30% or less, preferably 20% or less.

Furthermore, as a starting acrylic fiber, a fiber (a spinning stock solution of an AN polymer) after stretching and before heat treatment was spun according to a conventional method,
Use fibers that are stretched and oriented and have not been subjected to heat treatment such as dry edge densification or thermal relaxation treatment, especially wet or dry/wet spinning, water-swellable gel-like fibers after stretching (water swelling degree 30 to 150%). This is desirable because the dispersibility of the fibers in the reaction solution, the permeability of the reaction solution into the fibers, etc. are improved, and the introduction of cross-linking bonds and the hydrolysis reaction are performed uniformly and quickly. Needless to say, the degree of water swelling is the percentage of the amount of water contained or attached, expressed on a dry fiber weight basis.

(Function) The reason why the deodorizing fiber and the manufacturing method of the present invention have both flame retardancy and deodorizing performance has not been fully elucidated, but it is generally thought to be as follows.

That is, since starting from an AN-based polymer, nitrile groups that can cause cyanogen generation have substantially disappeared, and flame retardant performance is imparted by both hydrazine crosslinking and copper ion crosslinking. . Moreover, the existence of the double crosslinked structure in which the steel is intertwined may provide the deodorizing function.

Further, the processing performance of the inventive fiber is likely to be largely due to the orientation structure seen in the CR dichroic ratio (Example) The present invention will be specifically explained below with reference to Examples.

Parts and percentages in the examples are expressed on a weight basis unless otherwise specified.

In addition, the amount of residual nitrile groups (gaol/g), the amount of carboxyl groups (mmol/g), the amount of copper ions introduced (Ieq
/ g), LOI (limiting oxygen index), and deodorizing function were determined by the following methods.

(1) Amount of residual nitrile groups (mg+ol/g) AN/methyl acrylate (MA) ratio is 10010.80/
From the IR spectrum of the polymer of 20.50/50.30/To, 10/90, the absorbance at the absorption peak of the nitrile group was calculated to create a calibration curve, and based on this, the crosslinking was determined from the IR spectrum of the test fiber. The amount of nitrile groups remaining after introduction was calculated.

(2) Carboxyl group t (mmol/g) Accurately weigh approximately 1 g of sufficiently dried test fiber (X g), add 2001
After adding water, IN hydrochloric acid aqueous solution was added while heating to 50°C to adjust the pH to 2, and then a titration curve was determined using a 0, IN caustic soda aqueous solution according to a conventional method. From the titration curve, the amount of caustic soda aqueous solution consumed by carboxyl groups (
Ycc) was calculated. From the above measurement results, it was calculated using the following formula.

In addition, when polyvalent cations are included, it is necessary to determine the amount of these cations by a conventional method and correct the above formula.

(3) Copper ion introduction amount (meq/g) was determined by original purple analysis.

(4) LOI was conducted according to JIS-7201 lowest WI prime number measurement method.

(5) Deodorizing performance of 11g with the specified concentration and 50(
The mixture was placed in a 1++ l vial, and the gas concentration after 1 hour was measured using a gas chromatograph. The evaluated gases and their initial concentrations were: ammonia (NH3): 690pp;
Hydrogen ilide (H2S): 600 ppm, Methyl mercaptan: Iooppm.

(6) Combustion gas analysis: Burned according to JIS-7117 method, JIS-KO10
9, hydrogen cyanide was measured.

Example I AN polymer consisting of 90% AN and 10% methyl acrylate (hereinafter referred to as MA) (intrinsic viscosity [η] in dimethylformamide at 30°C: 1.2) 10
After spinning and stretching (total stretching ratio: 10 times) according to a conventional method, a spinning stock solution in which 90 parts of a 48% Rodan soda aqueous solution was dissolved was dried in an atmosphere of rolling ball/wet bulb = 120°C/60°C ( Raw material with a process shrinkage rate of 14%) and a single wk fiber fineness of 1.5d! 1taI (CR dichroism ratio 0.58) was obtained.

Raw material fiber I was treated with hydrazine and an aqueous NaOH solution under the conditions shown in Table 1, dehydrated, and immersed in a 5% aqueous copper sulfate solution at 80° C. for 60 minutes. Then wash with water,
Fibers 1 to 6 were obtained by drying. Got it! # The characteristic values of the fibers were tested and shown in Tables 1 and 2.

It can be seen that Examples 11 to 3 of the present invention are highly flame retardant and have excellent deodorizing performance without generating toxic gas during combustion. On the other hand, Comparative Example 4, which has a small increase in nitrogen due to hydrazine treatment, has deodorizing properties but has a tensile strength of o, 6v, /
The fiber had a low d and was brittle, and did not have physical properties that could withstand processing such as carding. The amount of nitrogen increase is small, but the introduction of carboxyl groups by hydrolysis is 2 +wmo
Comparative Example 5 of l/g had a tensile strength of 1.2 g/d and was flame retardant, but generated hydrogen cyanide gas when burned. It can be seen that in Comparative Example 6, which has a large increase in nitrogen, the amount of introduced carboxyl groups is low, so the deodorizing effect is low and it is not practical.

The following is a blank Example 2 Example 1 except that vinylidene chloride is used instead of MA
Raw material fiber II (CR dichroic ratio 0.55)
was obtained and treated in the same manner as the fiber NO12 of Example 1.

The obtained fiber had a desired increase of 3.8% and a carboxyl group introduction of 13. No residual -CN group was observed at Ommol/g, copper thickness was 2.7 meq/g, and tensile strength was 1.6 g.
/d, LOI32, there was no generation of hydrogen cyanide during combustion, and the deodorizing effect was less than 50 pp111 of ammonia, less than 2 ppm of hydrogen sulfide, and 8 ppm of methyl mercaptan, and had both flame retardancy and deodorizing properties.

(Effects of the invention) With the advent of the present invention, fiber properties that do not cause any problems in practical use are maintained, water swelling is suppressed to below a certain level, and high flame retardance is achieved that does not generate toxic gas when burned. A noteworthy effect of the present invention is that it provides a means for industrially advantageously producing fibers with deodorizing properties.

The deodorizing fiber thus obtained is widely used in fields of application where deodorizing properties are required in any usage form.

Patent applicant: Toyobo Co., Ltd.

Claims (1)

[Claims] 1. The increase in nitrogen content due to hydrazine crosslinking is 1.0 to
8.0% by weight of crosslinked acrylic fibers, some of the remaining nitrile groups contain 0.5 to 4.5 mmol/g of carboxyl groups ionically crosslinked with copper ions, and the rest contains amide groups. A flame-retardant deodorizing fiber that has been introduced into Japan and has a tensile strength of 1 g/d or more and a limiting oxygen index of 30 or more. 2. Introducing crosslinks into acrylic fibers by hydrazine treatment to adjust the increase in nitrogen content within the range of 1.0 to 8.0% by weight, and reduce the amount of remaining nitrile groups to 0 by hydrolysis reaction. Carboxyl groups were introduced into .5 to 4.5 mmol/g and amide groups were introduced into the remainder, then 0.5 to 4.5 mmol/g.
A method for producing deodorizing fibers having flame retardancy, which comprises forming ionic crosslinks with eq/g of copper ions.