The method of manufacture of aramid fabric

 

(57) Abstract:

The invention relates to the technology of aramid fabrics made from crystallized yarns, and can be used for manufacturing protective fire suits and other protective clothing. The fabric is impregnated with an aqueous solution containing 10-800 g/l of the polar solvent and can stand up to the swelling of no more than 36 hours Impregnate with wash solution and dried at a temperature not exceeding 200oWith no more than 30 minutes, the Fabric absorbs moisture and has good performance properties. 2 S. and 6 C.p. f-crystals.

The invention relates to absorbent aramid fabric, made of crystallized thread and intended for the manufacture of protective fire suits and other protective clothing.

In the last several patents, including U.S. patents 5323815, 5499663 and 5539928, talks about the benefits of using multifilament fabrics for the manufacture of the inner lining of the protective suit of fire. Such mnogoluchevye tissue, unlike fabrics from staple fibers, provide a smoother surface of the fabric, which increases the flexibility and mobility service and not obstructing the movement of fire during operation is okladki protective suit, fire or as a layer, serve as a basis for other layers of fabric, enhances your clothing, nevertheless mnogoluchevye tissue, in contrast to staple or fabrics made from yarn, have a low ability to absorb moisture. And, although the fire gets the opportunity to move with greater comfort, due to the fact that mnogoletija the fabric is less shackles of motion, moisture and evaporation, resulting from the metabolic processes occurring in the process of human activity, accumulate on the skin, because they are not absorbed by the threads of the fabric. This causes discomfort at the fire, and besides, moist skin prevents the freedom of movement of fire, which should provide protective clothing.

All fabrics used for manufacturing of protective clothing firefighters must meet the minimum performance requirements for resistance to flame, high temperatures and resistance to tear. Thus, the inner lining protective clothing fire and special service designed for those who work in conditions where there is a danger of ignition and the occurrence of high temperatures, usually made of aramid yarns and fibers. Most of these aramid yarn and fiber is e production with the aim to develop the mechanical properties of the fiber. Such filaments and fibers are largely (or completely) crystallized.

Specialists are well aware that the fiber and fabric of crystallized or essentially crystallized m-aramid have a closed surface and difficult to staining, or dressing, or processing of a fiber or fabric. For example, in U.S. patent 5096459 says that the fibers or fabrics made from crystallized m-aramid must be steam treated at a temperature of at least 120oC for about 15 minutes for water-soluble dyes and the media, which is used for impregnation, is absorbed into these threads and fiber.

In U.S. patent 4755335 say that even for the processing of m-aramid fibers and yarns that have never been subjected to drying, it was necessary to steam treatment at a temperature of from 110 to 140oWith that material, which is treated fiber or fabric, is absorbed properly.

In U.S. patent 4525168 States that you should cause swelling crystallized m-aramid fabrics or yarns, immersing them in a solvent, such as dimethylformamide, dimethylsulfoxide or dimethylacetamide, 30 minutes to open on the surface of the fiber access for the Ohm, to create a moisture absorbing aramid fabric from crystallized yarns used for the manufacture of protective clothing, including protective fire suits and other protective clothing. Another objective of the present invention is to develop a method of manufacturing such fabrics.

In the framework of the present invention proposed absorbent fabric containing aramid crystallized thread, in particular the fabric of the present invention contains 75 wt. wt.%. or more aramid crystallized threads.

Aramid crystallized filament used in the present invention, are a staple yarn, mnogoluchevye thread or a mixture of staple and mnogocelevykh thread and is made of m-aramid, p-aramid or mixtures of m-aramid and p-aramid fibers. Preferably, the main component of the fabric of the present invention was m-aramid thread.

The fabric of the present invention is best suited for the manufacture of protective clothing, which is a fire-protective clothing, consisting of outer shell, moisture-proof layer and teplonepronitsaemoe layer.

Protective clothing is truly izobrazheniya absorbent fabric, containing over 75% aramid crystallized fibers, and the method includes the following steps:

(a) impregnating the fabric with an aqueous solution containing from 10 to 800 grams per liter of the polar solvent;

(b) effecting contact of the solution with a cloth at room temperature over a period of time sufficient to swell the fibers of the fabric, but not more than 36 hours;

(C) impregnating the fabric finish, giving the fabric the ability to absorb moisture;

(g) drying the fabric at a temperature not exceeding 200oC for no more than 30 minutes.

The polar solvent used in the present invention are selected from the group comprising dimethylacetamide, dimethylformamide and dimethylsulfoxide.

In the method according to the present invention it is preferable that the impregnation was carried out under such pressure that the amount of absorbed solution ranged from 1% to 70% by weight of the dry yarn. It is also desirable to prevent drying of the impregnated fabric before step (g). With regard to the concentration of the solvent remaining in the tissue, the previous processing of the present invention, the method can be carried out so that the final concentration of solvent in Danilo 25 grams per liter of the polar solvent under pressure, the fabric has absorbed from 10 to 50 wt.% solution;

(b) leave the solution in contact with the tissue at room temperature for a period of about 16 hours;

(C) impregnating the fabric finish, giving the fabric the ability to absorb moisture;

(g) dried fabric at a temperature not exceeding 200oC for no more than 30 minutes. Polar solvents for this method include solvents that are selected from the group comprising dimethylacetamide, dimethylformamide and dimethylsulfoxide. In this variant implementation of the method according to the present invention, it is preferable to perform the treatment under such pressure that the amount of absorbed solution ranged from 1% to 70% by weight of the dry fabric. It is also preferable to prevent drying of the impregnated fabric before step (g).

In the present text the term "fabric, absorbent" refers to a fabric which initially absorbs moisture and continues to absorb at least 15 times. Long end the ability of the fabric to absorb moisture is very important to improve the functionality and extend the service life of protective clothing made of this fabric. The ability to absorb moisture is determined by observation of the WPPT, is diffusion drops into the fabric, resulting in a round spot. The absence of such a round spot means that the fabric is not able to absorb water, which is in contact with the surface of the fabric.

The term "wash" in the present text covers a series of operations including washing, rinsing and drying, which are used in Laundry when washing fabrics. During washing detergent is used in the usual concentrations, providing usteriana fabric from dirt and oil.

The present invention provides absorbent fabric crystallized from aramid fiber. The fabric of the present invention retains its ability to absorb moisture at least after 15 washings. Aramid yarn can be a m-aramid yarn, p-aramid filaments or mixtures of these aramid fiber. The fabric, in which the majority consists of m-aramid yarn is preferred. For the manufacture of the inner lining of the protective suit of fire, it is desirable that the fabric of the present invention represented m-aramid fabric from mnogocelevykh threads.

The fabric according to the present invention can be woven or knitted. Although plain weave Il the present invention can be used any netting or any method of manufacturing knitted fabrics.

The present invention provides a method of manufacturing absorbent fabric, containing more than 75% aramid crystallized yarns. The method includes the following steps:

(a) impregnation of tissue water restaura containing from 10 to 800 grams per liter of the polar solvent;

(b) effecting contact of the solution with a cloth at room temperature over a period of time sufficient to swell the fibers of the fabric, but not more than 36 hours;

(C) impregnating the fabric finish, giving it the ability to absorb moisture;

(g) drying the fabric at a temperature not exceeding 200oC for no more than 30 minutes.

Absorbent fabric according to the present invention can be used for a variety of purposes, including the manufacture of protective clothing and protective clothing fire.

A specific period of time between impregnation in a solution of solvent and impregnated finish, giving the fabric the ability to absorb moisture, which depends on the concentration of the solvent in a solution of water/solvent. When using higher concentrations of solvent less time would be required in order to activate the surface of aramid threads so that the threads absorbed and what their concentrations of solvent in a solution of water/solvent reduces the amount of solvent, which should soak into the fabric in the impregnation process. Preferably, the operation of impregnation was carried out under such pressure that the amount of absorbed solution ranged from 1 to 70%, calculated on the weight of dry fabric.

In many cases, when it is assumed that the skin of the user will be in direct contact with the tissue of the present invention, it is desirable to reduce the solvent content in the tissue, because not all of the solvent could be removed from the surface of the fabric during the drying process. The present invention provides a way in which the final concentration of solvent in the tissue is less than 1 wt.%. This preferred method includes the following steps:

(a) impregnating the fabric with an aqueous solution containing 25 grams per liter of the polar solvent under pressure so that the fabric absorbs from 10 to 50 wt.% solution;

(b) effecting contact of the solution with a cloth at room temperature for approximately 16 hours;

(C) impregnating the fabric with a solution of the wash, giving it the ability to absorb moisture;

(g) drying the fabric at a temperature not above 200oC for about 30 minutes.

In any embodiment, izobreteny the drying fabric, you can use any method well-known specialists.

The preferred solvent for activating the surface of the aramid crystallized thread is dimethylacetamide. Other polar solvents may also be used to activate the surface of the filaments, for example dimethylformamide or dimethyl sulfoxide. For each preferred solvent is a low concentration of from 1 to 5% by weight aqueous solution, this concentration will provide the activation of the surface of aramid threads, making it possible to carry out the dressing of a tissue structure giving the fabric the ability to absorb moisture, or other properties, or dye. At such low concentrations the amount of solvent remaining in the fabric after drying is less than approximately 1% and is low enough to ensure that the fabric after processing, can be used in cases where there is a direct contact of the fabric with the skin of the user.

The method according to the present invention allows to make tissue crystallized from aramid yarns ability for a long time to absorb moisture. Crystallized aramid yarn can be mnogoluchevye filaments or staple. Thread can be the to obtain tissue, with the ability for a long time to absorb moisture from mnogocelevykh m-aramid fiber. It is known that the surface mnogocelevykh crystallized yarns difficult dressing, which should ensure long-lasting results. If just soak mnogocelevoe m-aramid fabric from crystallized threads finish, giving the fabric the ability to absorb moisture, the fabric will lose this ability after five or less washings, unlike tissue obtained by the method according to the present invention.

The method according to the present invention also provides a more durable and uniform dressing of fabrics composed of staple fibres or mixtures of staple and mnogocelevykh threads.

The method according to the present invention can be applied to fabrics, containing aramid yarn as a secondary component, providing a more uniform dressing of tissue on the surface of the filaments are made of cloth.

The method according to the present invention can also be included in the impregnation process other wash or dyes in a mixture with apertures, giving the fabric the ability to absorb moisture. Thus, crystallized m-aramid is amide threads, this fabric will have the characteristics of aramid fabric at least in relation to the absorption of the dye carrying out the machining and dressing. If the fabric is to be used for the manufacture of protective clothing, it is sometimes required to produce a fabric from a mixture mnogocelevykh or staple aramid threads with other threads, or you may need it to protective fabric was 100 wt.% from aramid yarns or mnogocelevykh threads. The present invention allows to make the thread and woven fabrics of m-aramid crystallized yarns ability for a long time to absorb moisture even in those cases when the fabric is 100 wt.% consists of crystallized m-aramid fiber. If the fabric contains less than 100% and not more than 75% crystallized m-aramid filaments, the remaining threads are selected in accordance with the desired protective properties. Such threads can be a other thread that can withstand high temperatures, such as filaments of p-aramid, amorphous m-aramid, processed cotton, wool or viscose fibers and yarns from polybenzimidazole.

The method according to the present invention can be used to give the ability to absorb moisture fabrics, containing in quality.

Finish, giving the fabric the ability to absorb moisture, can be any of many known apretar, which is suitable for polyamide fibers. It is imperative that such wash can be applied by impregnation. The concentration of such wash in water solution used for impregnation of fabrics, should correspond to those concentrations, which are typically used for finishing fabrics. The preferred finishing, giving the fabric a tendency to absorb moisture and repel dirt, which can be used in the method according to the present invention, is manufactured by company "a stunning-Poulenc under the name "REPEL-O-TEX PSR 200".

In the present text refers to m-aramid fiber or thread is a fiber or fiber containing at least 25 mol.% (polymer) recurring structural units of the following formula:

[-CO-R1CO-NH-R2NH-], (I)

R1and/or R2in a single molecule can have the same values, but may have different values of the numbers below.

If R1and/or R2indicate any bivalent aromatic radical whose valence bonds are in metaprogram or under comparable angle relative to each of July or heterocyclic aromatic radicals, which can be single-core or multi-core. In the case of heterocyclic aromatic radicals, these radicals have one or two atoms of oxygen, nitrogen or sulfur in the aromatic nucleus.

Polynuclear aromatic radicals may be condensed with each other or connected to each other through connection With or via bridging groups, such as, for example, -O-, -CH2-, -S-, -CO - or-SO2.

Examples of polynuclear aromatic radicals whose valence bonds are in metaprogram or under comparable angle relative to each other, include 1,6-naftilan, 2,7-naftilan or 3,4'-biphenyldiol. A preferred example of a mononuclear aromatic radical of this type is 1,3-phenylene.

Preferred m-aramid polymer is MPD-I or copolymers containing at least 25 mol.% (polymer) MDP-I.

In this text the p-aramid fibers or filaments are fibers or filaments containing at least 25 mol.% (polymer) recurring structural units of the following formula:

[-CO-R1CO-NH-R2NH-], (I)

R1and/or R2in a single molecule can have the same values, but may have different sachanski radical, whose valence bonds are in paraprotein or under comparable angle relative to each other, then these radicals are mononuclear or polynuclear aromatic hydrocarbon radicals or heterocyclic aromatic radicals, which may be single-core or multi-core. In the case of heterocyclic aromatic radicals, these radicals have one or two atoms of oxygen, nitrogen or sulfur in the aromatic nucleus.

Polyhydric aromatic radicals may be condensed with each other or connected to each other through connection With or via bridging groups, such as, for example, -O-, -CH2-, -S-, -CO - or-SO2-.

Preferred p-aramid polymer is PPD-T or copolymers containing at least 25 mol.% (polymer) PPD-T.

M-aramid and p-aramid fibers or filaments suitable for making fabrics of the present invention and to implement the method according to the present invention are fibers and yarns manufactured by the company Du Pont under the trademark "KEVLAR" and "NOMEX", "Teijin under the trademark "CONEX" and similar products from other companies.

The fabric of the present invention mo is between, such as a jacket and pants, and any other clothing items that may be needed in order to provide protection from high temperatures and flames. Typically, these suits are made of several layers of fabric. Typical suit has an outer shell, which is usually made from a material resistant to abrasion, moisture-proof layer made of waterproof material, and teplonepronitsaemoe layer. Usually the lining material consisting of m-aramid filaments, placed under teplonepronitsaemoe layer, so that the specified material is in contact with the skin of the fire. It is assumed that this is the preferred usage of the fabric of the present invention, but the fabric of the present invention may be used in other layers of the protective suit where its use is deemed necessary and convenient.

The fabric of the present invention can be applied separately or in combination with other fabrics for the manufacture of protective clothing other types. For example, a fabric can be used separately for the manufacture of protective jackets or overalls, or as a lining for such service.

1. A method of manufacturing a fabric, fetivals impregnation of the fabric with an aqueous solution, containing from 10 to 800 g per liter of the polar solvent; (b) effecting contact of the solution with a cloth at room temperature over a period of time sufficient to swell the fibers of the fabric, but not more than 36 h; (C) impregnating the fabric with a solution of the wash, giving the fabric the ability to absorb moisture; (d) drying the fabric at a temperature not exceeding 200oWith over a period of time not exceeding 30 minutes

2. The method according to p. 1, in which the polar solvent is selected from the group consisting of dimethylacetamide, dimethylformamide and dimethyl sulfoxide.

3. The method according to p. 1, in which the impregnation is carried out under such pressure that the amount of absorbed solution ranged from 1 to 70% by weight, dry cloth.

4. The method according to p. 1, in which prior to step (g) drying the impregnated fabric.

5. A method of manufacturing a fabric having the ability to absorb moisture, in which the fabric contains aramid crystallized filament, and the final concentration of solvent in the fabric after drying is less than 1 wt.%, moreover, this method includes the following steps: (a) impregnating the fabric with an aqueous solution containing about 25 g per liter of the polar solvent under the same the KTA solution with a cloth at room temperature for approximately 16 h; (C) impregnating the fabric with a solution of the wash, giving the fabric the ability to absorb moisture; (d) drying the fabric at a temperature not exceeding 200oC for no more than 30 minutes

6. The method according to p. 5, in which the polar solvent is chosen from the group comprising dimethylacetamide, dimethylformamide and dimethylsulfoxide.

7. The method according to p. 5, in which the impregnation is carried out under such pressure that the amount of absorbed solution ranged from 1 to 70% by weight, dry cloth.

8. The method according to p. 5, in which prior to step (d) drying the fabric.

 

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