FI64404C - FRAMING PROCESSING OF CELLULOSE FIBERS - Google Patents

Description

64404

Method of fire-retardant cellulose fibers. for the manufacture of cellulose fibers

The present invention relates to a process for the preparation of blend fibers of fire-retardant cellulose and chlorine-containing polymers.

As such, cellulosic fibers such as cotton and viscose are highly flammable and fast burning.

The flammability of textiles, mainly their extinction properties, can be described by their LOI (Limiting Oxygen Index). The method uses the mixture of oxygen and nitrogen to determine the minimum oxygen content that the material needs to burn. If the LOI value is clearly higher than the oxygen content of the air (21%), combustion will go out on its own. The LOI values for the different fiber grades are shown in the following table (L. Pakkala, Textile Journal No. 3, 1973):

Table 1.

Fiber LOI

polyacrylonitrile 18.2 cotton 18.4 cellulose triacetate 18.4 cellulose diacetate 18.6 viscose 19.7 polyester 20.6 wool 25.2 modacrylic 26.8 PVC 37.1 cotton / polyester 50/50 18

The combustion susceptibility of a fiber mixture cannot be inferred from the flammability of the individual components, but must always be determined from the mixture.

Phosphorus, chlorine, bromine, antimony, tungsten or boron-containing compounds are used as flame retardants for cellulose fibers, which are usually added to the fiber during the finishing step. Bromine-containing organophosphorus compounds may also have been blended into the viscose prior to fiber spinning.

The most common flame retardants for cellulose fibers are as follows: 1. Ammonium phosphates, sulphates, halides and sodium borates

The disadvantage is the water solubility of these substances. The material loses its flame retardant properties after washing with water.

2. N-Methylol-2- (dimethylphosphonatoyl) propionamide and tetrakishhydroxymethylphosphonium chloride or sulphate The disadvantages of these permanent flame retardants are the high cost of the chemicals, the multi-stage fire retardant finish, the roughened and stiffened textile, the roughened and stiffened textiles. In addition, when heated, they emit powerful toxins such as phosphines.

3. Chlorinated hydrocarbon / antimony oxide The disadvantages of this finish for outdoor use only are the roughness and stiffness of the product and the impermeability of the air. The use of antimony causes occupational safety problems.

4. Tris-dibromopropyl phosphate mixed with viscose before spinning (approx. 15% of the amount of cellulose) A disadvantage of such "built-in" flame retardants n 64404 is their effect on the crystallization of cellulose, resulting in a sharp deterioration in fiber strength. The substance has been identified as mutagenic and its use is banned in the USA.

In the preparation of viscose fiber, it is not possible to dissolve in the aqueous cellulose xanthogenate solution (viscose) such organic polymers which, when co-spun into cellulose fiber, could have advantageous flame retardant properties (see Table 1).

It has been presented (Grinshpan, Kaputskii, Savitskaya, Zhurn,

Priklad, Khim. , 50_, 1977, 702) that e.g. PVC could be added to cellulose dissolved in a mixture of nitrogen tetroxide (N2O4) and dimethylformamide (DMF) and precipitated with the cellulose as a fiber. However, the production of cellulose fibers from cellulose / DMF solution has proven to be economically unprofitable and no production plant using this method has been set up.

It has also been suggested (Finnish Pat. No. 60578) that certain chlorine-containing polymers can be added to a solution of cellulose in dimethyl sulfoxide (DMSO) / paraformaldehyde (PF) and co-precipitates the chlorine-containing polymer with cellulose as a fiber having a fire resistance of at least 21% LOI.

However, it has been found that chlorine-containing polymers which are the least expensive and rich in flame retardant chlorine (such as PVC or PVC / PVAc copolymer) do not form a clear, homogeneous mixture with cellulose in a DMSO / PF solvent. This has the disadvantage that in order to have a flame retardant effect on the fibers made from the above blends, these cheap polymers have to be added to the cellulose more abundantly than chlorine-containing polymers which form a clear homogeneous mixture with the cellulose in DMSO / PF solvent. In this way, the advantage that could be obtained from the use of cheap polymers as flame retardants is partially lost. In addition, it has been found that the mechanical properties of fibers made from turbid, inhomogeneous solutions do not meet the requirements of 4 64404 for textile fibers.

U.S. Patent 4,302,252 states that polyamides, polyesters, polyethers, chitin and urethanes can be mixed into a LiCl / DMAC solution of cellulose. It appears from the experimental results shown in Table 2 of the present application that not all of the polymers mentioned in the patent form a spinnable blend with cellulose in LiCl / DMAC or LiCl / MP solvent systems. Thus, the production of blended fibers is not possible from all the blends mentioned in the patent, but the method apparently concerns the production of other products, at least in these cases. Although DMAC and MP are good solvents for synthetic polymers and, on the other hand, solvents for cellulose with LiCl, the combination of these solutions generally does not result in the formation of a clear, gel-free, spinnable mixture. Dissolution of different types of polymers (such as cellulose and PVC) in a common solvent results in a so-called to the compatibility problem: usually the mixture either divides into two phases, becomes cloudy, gels or one of the polymers precipitates. To illustrate, we refer to the results presented in Table 2, as well as the extensive experimental data published in the book:

Sonja Krause, Polymer Blends, Vol. 1, p. 54 - 63. It can be said that when two (or more) polymers are precipitated, these are generally incompatible with each other. Rather, polymer compatibility is the exception to the rule. This is well illustrated by the incompatibility of even as close polymers as some cellulose derivatives (see Polymer Blends).

From patents FI 60 578 and US 3 575 898, it can be stated that when a chlorine-containing polymer has been obtained into a cellulosic fiber by any method, improved fire resistance of the fiber has resulted. It should be noted, however, that the fire resistance of the blend fiber cannot be predicted from the fire resistance of the components to be blended.

SE 410 107 discloses DMAC as a solvent for PVC and GM 1 472 103 discloses DMAC as a solvent for polyacrylonitrile and

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5 64404 as a solvent for chlorinated hydrocarbons.

As previously shown, the solubility of the chlorine-containing polymer in DMAC is not a sufficient condition for the chlorine-containing polymer to be added to the cellulose LiCl / DMAC solution to form a clear, spinnable blend solution.

The object of the invention is to provide a process for the preparation of blended fibers of cellulose and chlorine-containing polymers with a fire resistance of at least 21% LOI.

The present invention is based on the finding that by using a new cellulose solvent, a mixture of lithium chloride and dimethylacetamide (DMAC) or lithium chloride and 1-methyl-2-pyrrolidone (DOS 30 27 033), various chlorine-containing polymers can be mixed into the cellulose in solution in such proportions that when the mixture is spun into fibers, a product is formed which has significantly improved flame retardant properties compared to cellulose fibers.

In addition, it has been found that although DMAC and 1-methyl-2-pyrrolidone are good solvents for synthetic polymers, chlorine-containing polymers can be blended into the cellulose solution only in certain proportions. In other cases, the mixture gels and cannot be spun into fibers. Table 2 on the next page shows the useful blend ratios of some polymers *.

6 64404

Table 2. Spinability of cellulose and some chlorine-containing polymer blends from LiCl / DMAC and LiCl / MP solutions + indicates that the blend is spinnable - indicates that the blend is not spinnable due to its geliness or turbidity

Blend ratio (cellulose / polymer) 90/10 70/30 50/50 30/70 10/90

Mixed polymer of acrylonitrile, methyl acrylate + + tin and butadiene 72/22/6 (Nitrile resin)

Copolymer of acrylonitrile and styrene _____ 35/65 (SAN)

Copolymer of acrylonitrile and vinylidene + + chloride (Modacrylic)

Acrylonitrile and vinyl chloride + + copolymer (Modacrylic)

Mixed polymer of ethylene and acrylic acid and Na or Zn ions (ionomer)

Mixed polymer of ethylene and vinyl acetate (EVA)

Gelatin _

Carboxymethylcellulose (CMC) _ "-Na salt _

Polyacrylates -

Po ly acrylic 1 amide _____

Po lyakryy 1 skin acid (PAA) _ - - - -

Polyacrylonitrile (PAN) 4- + ---

Polyamide 6.6 -----

Polyamides 11 -

Polyamideimide _____

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64404 7

Blend ratio (cellulose / polymer) 90/10 70/30 50/50 30/70 10/90

Polybutene ter fe laa11i _____

Polyethylene terephthalate _____

Polyethylene (PE) _____

Polyethylene, chlorinated (PE) ", chlorosulfonated _____

Polycarbonate (PC) -

Polyethyl 1 imetacrylate (PMMA) _____

Polystyrene (PS) _

Polyurethane (PU) -

Polyvinyl alcohol (PV &) ++ ---

Polyvinyl acetate (PVAc) _____

Polyvinyl chloride (PVC) + + ---

Polyvinyl chloride, post-chlorinated - (CPVC)

Polyvinylpyrrolidone (PVP) + + + + +

Villa _____

90/10 copolymer of vinylidene chloride and vinyl + + chloride (PVDC / PVC)

87/13 copolymer of vinyl chloride and vinyl acetate (PVC / PVAc) + + + DMAC = dimethylacetamide MP = 1- ^ Tetyl-2-pyrrolidone 8 64404

The process according to the invention is characterized in that the chlorine-containing polymer, which is either a copolymer of acrylonitrile and vinylidene chloride (modacrylic), a copolymer of acrylonitrile and vinyl chloride vinyl and vinylide (modacrylic) the copolymer (PVC / PVAc), or a mixture thereof, is mixed either as such or dissolved in an organic solvent in a solution of cellulose lithium chloride / dimethylacetamide or lithium chloride / 1-methyl-2-pyrrolidone to form a mixture of at least 10 but not more than 60 a weight percent of said chlorine-containing polymer based on the total amount of cellulose and chlorine-containing polymer, and the fact that fibers are prepared from the resulting mixture by feeding it into a solution in which the polymer mixture precipitates in fiber form. The method produces a fiber with an LOI of at least 21% C> 2, so that its flame retardant properties are significantly better than with cellulose fiber alone.

The advantages of the method over known methods of fire protection of cellulose fibers are: a) The method gives a product in which the fire protection agent is "built-in". The mixture is homogeneous throughout the fiber, b) the flame retardant does not dissolve in the fiber production in the spinning bath, but precipitates completely with the cellulose fiber, no chemical losses occur, c) the flame retardants are not water soluble, so the fire protection of the fiber is permanent and does not deteriorate in washing, d) - the substances are long-chain polymers, they are oriented in fiber production like cellulose and do not affect the fiber's strength properties as adversely as known flame retardants,

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64404 9 (e) the addition of chlorine-containing polymers to the cellulose fiber by this method does not affect the comfort of the fiber; (f) the use of chlorine-containing polymers does not pose a health risk;

The following examples are intended to illustrate some preferred embodiments of the method.

Example 1.

Preparation of cellulose solution using LiCl / DMAC solvent 150 g of wet prehydrolysed birch sulfate cellulose (65% water) was kept for 1 day in 1000 ml of dimethylacetamide (DMAC). After filtration, the cellulose was pressed as dry as possible and treated for another 2 hours with a new batch of DMAC. Finally, the cellulose was compressed to a dry matter content of 25%. 48.9 g of lithium chloride was dissolved at 60 ° C in 495 g of DMAC. To the room temperature LiCl solution was added cellulose treated with the above DMAC, which dissolved in two hours. The clear 6% cellulose solution was heated to 90 ° C and filtered. The viscosity of the resulting cellulose solution was 420 ° C at 23 ° C.

Example 2.

Preparation of cellulose solution using LiCl / MP-1 solvent 52 g of air-dry prehydrolysed birch sulphate cellulose was "activated" by keeping it for 1 hour in 1000 64404 in 10 ml of water. The dry-compressed cellulose was kept for 3 hours in 1000 ml of 1-methyl-2-pyrrolidone, after which it was compressed to a dry matter content of 25% and the treatment was repeated with a dry solvent batch. The cellulose was then dissolved at room temperature in 544 g of a lithium chloride / 1-methyl-2-pyrrolidone solution having a LiCl content of 9%. The resulting clear 6% cellulose solution was filtered at 90 ° C. The viscosity of the solution at 23 ° C was 480 P.

Example 3.

Manufacture of cellulose / PVC 60/40 blended fibers

The cellulose solution prepared as mentioned in Example 2 was mixed with 173 g of a DMAC solution containing 20% PVC. The mixture solution was shaken for one hour at room temperature. The resulting clear, good quality solution had a viscosity of 300 P at 23 ° C. The solution was fed through water through holes in the spinneret (0 0.08 mm) and the fiber bundle was lifted through 200 mm rolls of aqueous solution where it was stretched by 25%, washed, washed and dried. . The spinning speed was 20 m / min. The fiber produced felt soft and warm and had sufficient strength for textile use. The knitted fiber knit was measured to have an LOI of 24-25% C> 2 and self-extinguished in air. The LOI of a similarly prepared cellulosic fiber was measured to be 18-19% O 2.

Example 4.

Manufacture of cellulose / PVC 80/20 alloy fibers

To the cellulose solution prepared as in Example 2, 6.5 g of PVC powder was added and the mixture was stirred at 50 ° C for 3 h. The clear solution 64404 11 was filtered and spun into fibers as described in Example 3. The LOI of the resulting fiber was measured to be 22-23% C> 2 and continued to burn in air very slowly or quenched.

Example 5.

Manufacture of cellulose / vinyl chloride-vinyl acetate copolymer 40/60 blend fibers

To a LiCl / 1-methyl-2-pyrrolidone solution of cellulose prepared as mentioned in Example 2 was added 78 g of a vinyl chloride-vinyl acetate copolymer dissolved in 1-methyl-2-pyrrolidone. The mixture was shaken for 2 h at room temperature and the clear, good quality mixture solution was spun into fibers as described in Example 3. The resulting white blend fiber was strong enough for textile use. The knitted fiber knit self-extinguished in air after the flame was removed and its LOI was measured to be 27-28% 02 ·

Example 6.

Manufacture of cellulose / vinylidene chloride-vinyl chloride copolymer 80/20 blend fibers

To the LiCl / DMAC solution of cellulose prepared as mentioned in Example 1 was mixed 13 g of a vinylidene chloride-vinyl chloride copolymer dissolved in 1-methyl-2-pyrrolidone. The clear mixture solution was spun into a fiber as shown in Example 3. The LOI of the pleasant-feeling fiber was measured to be 23-24% o2 and self-extinguished in air.

The strength of the blend fiber was satisfactory.

12 64404

Example 7.

Preparation of cellulose / vinylidene chloride-vinyl chloride copolymer / modacrylic 70/20/10 blended fibers

To the LiCl / DMAC solution of cellulose prepared as mentioned in Example 1, 14.9 g of a vinylidene chloride-vinyl chloride copolymer and 7.4 g of modacrylic fiber dissolved in DMAC were mixed. Stirring was continued for 2 hours. The resulting clear mixture solution was spun into fibers as described in Example 3. The prepared fiber felt soft and had better strength than the fiber shown in Example 6. The blend fiber spontaneously extinguished in air after flame removal and was measured to have an LOI of 25-26% Cl 2.

Example 8.

Manufacture of cellulose / modacrylic 90/10 blended fibers

To the cellulose solution prepared as mentioned in Example 1, 5.8 g of modacrylic fiber dissolved in DMAC was mixed. The mixture solution was spun into a fiber as mentioned in Example 3. The pleasantly felt blend fiber continued to burn slowly in air after flame removal, and its LOI was measured to be 21-22% O 2. The fiber had good strength.

Example 9.

Preparation of cellulose / PVC 60/40 blend fibers using DMSO / PF solvent 83 g of air-dry, prehydrolysed cellulose, 83 g of para-formaldehyde and 1100 g of dimethyl sulfoxide were heated in a 2 L vessel to 120 ° C for about 1.5 hours. The resulting clear solution was maintained at 64404 13 120 ° C for an additional 2.5 hours to remove excess formaldehyde.

The solution was filtered hot and mixed with DMSO and 55.3 g of polyvinyl chloride. The mixture was shaken for 2 hours at 70 ° C. The resulting cloudy mixture was fed through holes in a spinning nozzle into an aqueous spinning bath. The fiber bundle was stretched, washed and dried. The LOI of the finished fiber bundle was measured to be 24-25% Oj. The tensile strength of the blended fiber when air-conditioned was 60 mN / tex and when wet when it was 15 mN / tex, which is not sufficient strength for textile use.

Example 10.

Preparation of cellulose / PVC-PVAc 40/60 blends in DMSO / PF solvent

To the filtered cellulose solution prepared as in Example 9 was added DMSO and 125 g of vinyl chloride-vinyl acetate copolymer. The mixture darkened rapidly and gelled and no fibers could be made from it.

Claims (8)

64404 Claims u ^ w A process for the preparation of blend fibers of fire-retardant cellulose and chlorine-containing polymers having a fire resistance of at least 21% LOI, characterized in that a) a chlorine-containing polymer which is either a copolymer of acrylonitrile and vinylidene chloride acrylonitrile and acrylonitrile (modacrylic) polyvinyl chloride (PVC) copolymer of vinylidene chloride and vinyl chloride (PVDC / PVC) or a copolymer of vinyl chloride and vinyl acetate (PVC / PVAc) or a mixture thereof either as such or dissolved in an organic solvent lithium lithium chloride / dimethyl cellulose / dimethyl To a 2-pyrrolidone solution so as to form a mixture of at least 10% but not more than 60% by weight of said chlorine-containing polymer, based on the sum of cellulose and chlorine-containing polymer, b) preparing the resulting fibers by feeding fibers to a solution u in fiber form. Process according to Claim 1, characterized in that the chlorine-containing polymer is polyvinyl chloride which is present in the mixture in an amount of at most 40% of the total amount of PVC and cellulose. Process according to Claim 1, characterized in that the chlorine-containing polymer is vinyl chloride and vinyl chloride. copolymer of acetate, and the solvent is lithium chloride / 1-methyl-2-pyrrolidone. Process according to Claim 1, characterized in that the chlorine-containing polymer is a copolymer of vinyl chloride and vinyl acetate which is present in the mixture in an amount of up to 40% of the total amount of copolymer and cellulose when the solvent is 1 lithium chloride / dimethylacetamide. 64404 Process according to Claim 1, characterized in that the chlorine-containing polymer is a copolymer of vinylidene chloride and vinyl chloride which is not mixed in an amount of up to 40% of the total amount of chlorine-containing polymers and cellulose. Process according to Claim 1, characterized in that the chlorine-containing polymer is modacrylic in a mixture of at most 40% of the total amount of modal acrylic and cellulose. 1. A formulation for the manufacture of a brand name blend fiber comprising a cellulose and a chlorinated polymer, the brand name of which is an LOI enhancer with a value of 21%, which can be used as a chlorinated polymer, and which may be treated with a sample. of acrylonitrile and vinyl chloride (modacryl), a shampoo of acrylonitrile and vinyl chloride (modacrylic), polyvinyl chloride (PVC), a shampoo of vinyl dichloride and vinyl chloride (PVDC / PVC) or a shampoo of vinyl chloride and vinyl chloride In the case of a bleaching agent which is soluble or organic in the form of a solution of cellulosic lithium chloride / dimethylacetamide or lithium chloride / 1-methyl-2-pyrrolidone solution in the case of total cells Cellulose and chlorinated polymers, and in the case of (b) in the form of bleaching frameworks of the fibrin genome of the tensed state, les fibrer.