TW201923178A - Flame retardant Lyocell filament - Google Patents

Abstract

The invention relates to a filament having flame retardant properties, as well as methods for its preparation and its use. The filament according to the invention are Lyocell filaments.

Description

Flame retardant filament

The present invention relates to a flame-resistant rayon filament and a method and application for manufacturing the flame-resistant filament.

Flame retardant fibers are used in a variety of applications, from technical fabrics to outerwear for clothing. Although cellulosic fibers have been used in these applications for a long time, cellulose filaments have not received much attention and use in this field due to their unsatisfactory dimensional stability and low wet strength. The wording filaments used herein are considered continuous based on, for example, the definition of BISFA (International Man-made Fiber Standards Agency) terminology (other terms used in this specification and the scope of the patent application are defined in the BISFA publication and are also found below) and are considered continuous A very long (endless) fiber with a very long length will distinguish filaments for shorter types of fibers (e.g. short fibers, flocks). For this shorter type of fiber, the issue of dimensional stability and strength has less relevance, so cellulose staple fibers and the like have been widely used and are also available in versions containing additives (including flame retardants) widely used. However, for filaments, issues involving dimensional stability and strength properties, especially wet strength, are of greater concern. This is one of the reasons why cellulose filaments, especially flame retardant filaments, have not been widely used.

In the prior art, flame retardants have been used as additives to prepare slime fibers and short fibers. However, cellulose filaments, such as viscose filaments, do not exhibit the required properties when prepared with flame retardants, such as dimensional stability and sufficient wet and dry strength. This is necessary to achieve proper textile properties in terms of survival in demanding textile processes such as weaving and dyeing and finishing processes, as well as in shrinkage during washing or tearing. Object of the invention

In view of the above-mentioned problems, an object of the present invention is to provide a flame-resistant filament (FR filament) that meets high quality standards in terms of strength and dimensional stability. The wording flame-resistant filament as used herein defines a filament that is not only coated with a flame retardant material, but also incorporates the flame retardant into the filament matrix.

This problem can be solved according to the present invention by a filament such as the scope of patent application item 1. Preferable specific examples are listed in items 2 to 5 of the scope of patent application. The present invention additionally provides a method such as item 6 of the scope of patent application, which again lists preferred specific solutions in items 7 to 9 of the scope of patent application. Finally, the present invention provides applications such as the scope of application for item 10 and products of the scope of application for item 11, the preferred specific examples of which are defined in areas 12 to 15 of the scope of patent application. Further explanation is provided in the following description.

It was surprisingly found that flame retardant nylon fiber filaments did overcome the shortcomings of prior art and the recognition and concerns associated with flame retardant fiber surface filaments (such as viscous filaments). As described herein, Lycra filaments surprisingly show a very satisfactory balance of properties and can be reliably produced in the form of flame retardant filaments. These flame retardant filaments have shown great promise for the manufacture of a variety of different products, including filament yarns and fabrics for protective clothing or others such as those made for filaments and yarns according to the invention Fabrics or nonwovens for technical applications.

Lycra fibers are well known in the art, and their general manufacturing methods are disclosed in, for example, US 4,246,221 and the BISFA (International Man-made Fiber Standards Agency) publication "Terminology of Man-Made Fibers", 2009 edition. These two references are incorporated herein by reference.

Also cited are WO 02/18682 A1 and WO 02/72929 A1, which are related to a method for producing a cellulose filament yarn, and are incorporated herein in their entirety.

As described above, the FR filaments according to the present invention are rayon filaments, that is, filaments manufactured using the rayon method. This method is well known to those skilled in the art and will therefore not be described in detail here. This example provides an illustration of this method, as well as the patent literature described herein. The filament may have any desired linear density, with suitable values in the range of 0.6 to 4 dtex, and preferred values in the range of 0.8 to 2 dtex. The crude cellulose product used to prepare the flame retardant filaments of the present invention is not critical, and any type of crude product suitable for the fiber process can be used.

As mentioned above, and in particular the present invention is characterized in that the novel and original flame-retardant filaments indeed show a very surprising balance of mechanical (strength / toughness) properties in dry and wet conditions, and in addition very Satisfactory dimensional stability. At the same time, the required flame retardancy can be obtained even in filaments without unduly sacrificing mechanical properties. The strength properties that can be obtained with the filaments of the present invention are usually measured in a humidity-conditioned state, and for the flame-retardant filaments of the present invention, these properties are generally as follows:

The average dry strength (FFk) is at least 22 cN / tex. The average dry breaking elongation (FDk) of the filaments is at least 6%, preferably between 6% and 8%. These properties were evaluated using the following test equipment and parameters: Test equipment: USTER® Tensorapid 4 2.4.2 UTR4 / 500N: Test length: 500 mm clamp speed: 60 mm / min clamp pressure: 30% Pre-tension: 4,1 cN

The filaments according to the invention therefore indeed show a favourable high dimensional stability, which is advantageous for the yarns and cloths produced therefrom. In this way, the flame-retardant filaments of the present invention can be used to make high-quality flame-retardant products.

As described above, the filament of the present invention is a flame-retardant filament, that is, a filament doped with a flame retardant. Since the filaments of the present invention are rayon filaments, this can be achieved by including the flame retardant in the spinning solution in a suitable manner (or at least in the composition before spinning the filaments). The addition of flame retardants is further exemplified in the examples contained herein. The type of flame retardant is not important so long as it can be typically included in the flame retardant solution, preferably in the form of an aqueous solution, in the spinning solution or spinning composition. However, the flame retardant can also be included in the form of a finely ground powder or a dispersion of this finely ground powder. To use this solid form flame retardant, it is preferred that the average particle diameter of the flame retardant is at most 50% of the diameter of the filament, more preferably at most 30%, and more preferably at most 10 of the diameter of the filament. %.

The amount of flame retardant in the final filament is typically in the range of 2 to 50% by weight, preferably 10 to 40% by weight, and still more preferably 15 to 30% by weight. This amount can be adjusted according to demand, for example, the degree of flame retardance required, and can be adjusted by the ratio of cellulose to flame retardant in the spinning solution or spinning composition.

As mentioned above, the type of flame retardant is not important. However, flame retardants based on compounds containing nitrogen and phosphorus are preferred, such as those commercially available under the registered trademark Aflammit®. Particularly preferred are organophosphorus compounds, such as Aflammit KWB. Any flame retardant used may be pre-treated, such as grinding, to obtain a flame retardant with a particle size suitable for the spinning process (if it is insoluble in the spinning composition), the particle size usually depends on the target length Wire diameter. Those skilled in the art know this process.

In a specific example of the present invention, flame retardants belonging to the oxidative condensation products of tetrahydroxyalkylphosphonium salts with ammonia and / or nitrogen-containing compounds containing one or more amine groups are excluded.

As outlined above, the flame retardant filaments according to the invention are rayon filaments. Therefore, the method for preparing a filament according to the present invention includes providing a spinning solution containing at least cellulose, water, NMMO and a flame retardant, and spinning the solution and regenerating the filament in a manner known to those skilled in the art. According to the present invention, it is determined that a spinning speed of about 250 to 750 m / min can be used, such as 300 to 600, preferably 350 to 450 m / min. During this process, any other required additives and stabilizers can be added as needed, such as dyes and pigments.

The filaments can of course be subjected to any usual post-spinning process, such as coating, finishing, and the like. Those skilled in the art will be able to select the appropriate processing based on the intended use of the flame retardant filament.

The flame-retardant filaments according to the invention can be used to make other products, such as yarns, cloths and nonwovens. The yarns may contain different numbers of filaments of the invention, suitable examples are 10 to 200 filaments, such as 15 to 150, and specific examples are 25 to 100 filaments. Yarn titers can cover a wide range, depending on the intended field of use, and examples are in the range of 30 to 150 deniers, such as 50 to 120 deniers. Due to the unique balance of properties, such as high mechanical strength and relatively low elongation at break, the filaments of the present invention can be used to make high-quality products with high dimensional stability.

The flame retardant filaments of the present invention can be used alone in the manufacture of other (textile) products, but the filaments can also be blended with other types of fibers to produce a filament mixture with the desired properties and characteristics. In particular, if the desired product does not require a high degree of flame retardancy, the flame retardant filaments of the present invention can be blended with other fibers as an option. If in any case a high-strength fabric is required, another option is to blend the flame-resistant filament with the high-strength filament. As explained above, it has been shown that the flame-resistant filaments of the present invention also provide good properties in the form of blends with other types of fibers.

The following examples do illustrate the invention. Examples

The following examples demonstrate the superior properties of the FR Lycra filaments of the present invention compared to non-flammable mucus, copper ammonium, and Lycra filaments.

Example 1 shows the properties of the flame-retardant Lycra filaments according to the present invention.

Comparative Examples 1 to 3 show properties of slime filaments, copper ammonium filaments, and nylon filaments, respectively, all of which are free of flame retardant components.

The filament according to the present invention according to Example 1 was produced in the following manner:

Wood pulp (cellulose) was impregnated with 78% N-methyl-morpholine-N-oxide (NMMO) aqueous solution and a small amount of stabilizer. The resulting suspension contained 11.6% cellulose, 68% NMMO, 20.4% water and stabilizer GPE. The wood pulp is composed of a mixture of sulfite cellulose and sulfate cellulose. A flame retardant (Aflammit KWB, suspension of 20% ground Aflammit KWB in 50% NMMO aqueous solution) was added to prepare a final spinning solution, and excess water was removed from the slurry under the action of shearing and heating to obtain A fiber-free spinning solution containing 12.7% cellulose, 73.8% NMMO, 10.7% water, and 2.8% flame retardant (all% refers to the weight based on the total composition).

The spinning solution was filtered and extruded at 114 ° C in a dry-wet process, wherein the spinning solution was extruded into an air gap through a nozzle. To stabilize the extrusion process, an air flow is provided to the air gap. The spinning speed was 400 m / min.

After passing through the air gap, the cellulose was precipitated in a spinning bath containing 10% NMMO and the rest of the water.

The endless filaments thus obtained are washed with water, impregnated with a processing agent, dried, and wound around a bobbin. Wash in complete counter-current desalinated water. For drying, use a contact dryer to reduce the humidity to 10.5%.

These filaments are used to generate multi-filaments composed of monofilaments. An untwisted filament yarn is produced from the multifilament. From this filament yarn, cloth can be manufactured. The linear density of the manufactured yarn is between 20 and 200 dtex, preferably between 50 and 150 dtex.

For further details of this process, reference is made to US 4,246,221, WO 02/18682 A1 and WO 02/72929 A1.

The filaments of Comparative Examples 1 to 3 were manufactured using a conventional method, and the rayon filaments were manufactured using an experimental device as described in Example 1, except that no flame retardant component was used.

The respective properties are described below:

Comparative Examples 1 and 2 show that even without the addition of a flame retardant, the slime and copper ammonium filaments did indeed show completely unsatisfactory properties. On the other hand, compared with Comparative Example 3 (that is, non-flame-retardant fiber-reinforced filaments), the flame-retardant fiber-reinforced filaments did show very satisfactory properties even though the mechanical properties were slightly lower. However, the properties of the flame-retardant nylon fiber filaments according to the present invention are significantly improved compared to non-flammable slime and copper ammonium filaments. Comparative examples using other types of cellulose filaments did encounter extreme imbalances in mechanical properties, so it was not possible to produce dimensionally stable products for these filaments. At the same time, the flame-retardant filaments of the present invention, in addition to showing very satisfactory flame-retardant properties, also show an extreme balance of mechanical properties. Flame retardant lining

75 g of yarn (den 90/40 (40 multifilaments with a total fineness of 90 denier), yarn fineness dtex 100f40), and yarn fineness dtex 100f40) obtained by using the flame-retardant nylon fiber filament of the present invention, to produce 75 g / m ² of lining. Use this liner for a three-layer assembly, including a moisture barrier (laminated, 148 g / m ² , 50% meta-aramid / 50% Lenzing FR (flame-retardant viscose short fiber) / PU film ), Outer fabric (260 g / m ² ; 50% Lenzing FR, 38% para-aramide, 12% PA) and the above-defined lining (100% flame-retardant nylon fiber filament), evaluate the three-layer assembly Flame retardant. The three-layer assembly passed the flame spread test (testing flame to outer fabric and testing flame to lining) according to EN ISO 15025: 2002 procedure A and fulfilled all necessary requirements of EN 469 (EN 533 Index 3).

Claims (14)

A flame retardant filament (FR filament) containing a flame retardant and cellulose, characterized in that the filament is a rayon filament. For example, the flame retardant filaments in the scope of patent application No. 1 have an average dry tenacity of at least 22 cN / tex. For example, the flame retardant filaments of the scope of application for patent No. 1 or 2 have an average wet strength of at least 11 cN / tex. For example, the flame retardant filament according to any one of claims 1 to 4, wherein the amount of the flame retardant is 2 to 50% by weight. A method for manufacturing a flame retardant filament as in any one of claims 1 to 4 of the scope of patent application, comprising providing a composition comprising a wooden paddle, NMMO, water and a flame retardant, and spinning the solution to Manufacture of filaments. For example, the method of claim 5 of the patent scope, wherein the amount of the flame retardant and the wooden paddle in the spinning solution is in the range of 12 to 25% of the spinning solution. For example, the method of claim 5 and / or 6, wherein the spinning speed is in the range of 250 to 750 m / min. The method according to any one of claims 5 to 7, wherein the wooden paddle comprises sulfite cellulose and sulfate cellulose. A use of a flame retardant filament manufactured according to any one of claims 1 to 4 or according to any of claims 5 to 8 in the scope of patent application, which is used to prepare yarns, cloths and textiles. A fabric or textile product comprising a flame-resistant filament manufactured according to any one of claims 1 to 4 or according to any one of claims 5 to 8. For example, the use or product of any one of claims 9 or 10, wherein the flame-retardant filament is blended with other types of fibers. If the application or product of any of the patent scope items 9 to 11 is applied, it meets EN ISO 15025: 2002 process B-edge flaming test according to EN ISO 14 116 classification "limited flame diffusion index 3" Requirements. If the application or product according to any one of claims 9 to 12 is applied for, it is a multifilament yarn. The application or product according to any one of claims 9 to 13, wherein the flame retardant filament comprises a resin finish.