JP2722254B2 - Flame retardant acrylic fiber with excellent rust prevention, light stability and transparency - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a flame-retardant acrylic fiber excellent in rust prevention, light stability and transparency.

<Conventional Technology> Acrylic fibers have long been used in a wide range of applications because of their excellent texture and dyeability. In particular, in recent years, demands have been growing for halogen-containing acrylic fibers, so-called modacrylic fibers, which have improved their flammability, which is the biggest drawback of them, due to the sophistication of social demands.

However, in the case of modacrylic fiber, especially when the chlorine component is contained in the copolymer component, the fiber undergoes a dechlorination reaction by light or heat, causing rusting in the fiber manufacturing process and spinning process, and discoloration due to yellowing. Has become a factor.

Various measures have been taken to solve the problem of fading due to yellowing (JP-A-46-3444, JP-A-51-82).
No. 23, JP-B-51-29240, JP-A-53-134926
JP-B-53-19689), various light stabilizers are also introduced, but the production method and means are specific to each step, and are not widely applicable. In particular, there are adverse effects such as spinning and dyeing (devitrification), and no satisfactory technology has been found yet.

Regarding the problem of rust in the manufacturing process and spinning process,
Although some improvement proposals have been proposed, they are inadequate, and despite the fact that chlorine-containing flame-retardant modacrylic fibers are a major problem, no effective means of improving raw cotton has yet been found. .

<Problems to be Solved by the Invention> As described above, the present invention solves the problem of rusting in the manufacturing process and the spinning process of the flame-retardant acrylic fiber containing vinylidene chloride or vinyl chloride, and furthermore, has light resistance stability. To provide a flame-retardant acrylic fiber having good transparency.

<Means for Solving the Problems> The gist of the present invention is that acrylonitrile 45 to
Dialkyl tin maleate based on a polymer consisting of 70% by weight, vinylidene chloride or vinyl chloride 30 to 55% by weight, sulfonic acid group-containing monomer 0.5 to 3% by weight and unsaturated monomer 0 to 5.5% by weight 0.8-2.5% by weight of polymer, organic acid
A fiber made of a polymer to which 0.4% by weight or more is added, and further, a bisphenol A type water-soluble epoxy resin or an epoxy compound represented by the following formula (1) is attached to the fiber surface in an amount of 0.2 to 1.5% by weight based on the fiber. A flame-retardant acrylic fiber having excellent rust resistance, light stability, and transparency, which is characterized by being hampered.

However, in the formula, a = 1.6, b = 4.4, R = alkyl group The polymer used in the present invention needs to be an acrylonitrile-based polymer obtained by copolymerizing a halogen-containing monomer.

As a method of containing a halogen in the acrylic fiber, a method of copolymerizing acrylonitrile and a halogen-containing monomer is generally used, and the fiber obtained from the copolymer is most preferable because the performance of the acrylic fiber is not impaired. . Examples of the halogen-containing monomer include vinyl chloride, vinylidene chloride and vinyl bromide, and vinylidene chloride and vinyl chloride are preferably used. In particular, vinylidene chloride has a relatively high boiling point, so it is easy to handle in the polymerization process, and the characteristics of the fiber produced from the vinylidene chloride copolymer are considered to be general acrylic fibers in view of the balance with the level of flame retardancy. Since it has near excellent mechanical or thermal properties, it can be used advantageously.

The content of vinylidene chloride or vinyl chloride is required to be 30% by weight or more in order to maintain effective flame retardancy as a flame retardant fiber. In addition, if 55% by weight is contained, it can be used for most products in applications currently used in practical use, and when combined with flame retardant aids, this fiber can be applied to all applications It is.

The thus obtained chlorine-containing acrylonitrile-based polymer is shaped into fibers by a conventional spinning method of acrylic fibers. However, it is most preferable to form fibers by a wet spinning method from the viewpoint of low productivity or heat history.

However, when a chlorine-containing acrylonitrile-based polymer is shaped into a fiber by a wet spinning method, there is a disadvantage that voids are easily generated due to its solidification characteristics. These voids are once crushed in the drying process, but are regenerated in the moist heat relaxation process or the dyeing process, devitrifying the fibers, and impairing the sharpness of the dye.

In order to solve such a problem, a method of copolymerizing a sulfonic acid group-containing monomer such as sodium methacrylsulfonate to introduce a sulfonic acid group into the polymer is effective, Is 0.5 to 3% by weight, preferably 1.0 to 3.0% by weight.

Various unsaturated monomers as other copolymer components are known, but these are monomers that can be introduced for improving the properties of the fiber, for example, acrylic acid, methacrylic acid,
Examples thereof include vinyl acetate, methacrylamide, and esters thereof. However, the amount of copolymerization should be limited to at most 5.5% by weight, and further incorporation significantly reduces the heat resistance and other properties of the fiber.

In order to improve the rustability and light stability of the fiber of the present invention, 0.5 to 2.5% by weight of a dialkyltin maleate polymer and 0.4% by weight of an organic acid are added to the polymer, and bisphenol is further added. A type water-soluble epoxy resin or the epoxy compound represented by the above formula (1) is added to the fiber in an amount of 0.
2 to 1.5% by weight must be attached to the fiber surface.

The dialkyl tin maleate polymer has an effect of improving rust prevention and light stability by being added to the polymer used in the present invention. The alkyl group of the dialkyl tin maleate polymer can be arbitrarily selected, but the smaller the alkyl group, the higher the solubility in the solvent used for yarn-protecting the fiber of the present invention, which is preferable in terms of operability.

Adding an organotin compound to a chlorine-containing polymer,
This is proposed in Japanese Patent Application Laid-Open Nos. 57-82516 and 57-89613. An object of these inventions is to improve the flame retardancy without impairing the transparency of the flame-retardant acrylic fiber, and the organotin compound is used for the purpose as a flame retardant aid. In addition, there is a description that coexistence with a glycidyl methacrylate polymer is effective for rust prevention.

The organotin compound described in the patent needs to be a low molecular weight substance in order to maintain the transparency of the fiber. When such a low-molecular organotin compound is added to the polymer used in the present invention to form a fiber, sufficient light stability cannot be obtained. On the other hand, the dialkyltin maleate polymer used in the present invention has sufficient light stability, but cannot maintain the transparency of the fiber, and is fundamentally different from the organotin compound used in the patent. It is. In addition, coexistence of a glycidyl methacrylate-based polymer requires preparation of the glycidyl methacrylate-based polymer in advance, and is not an industrially effective method.

The content of dialkyl tin maleate polymer is 0.8-2.5
% By weight, preferably 1.0 to 2.0% by weight. 0.8% by weight
If less than 2.5, the desired rust prevention effect and light stability cannot be obtained, and
If the amount is more than 10% by weight, the solubility in the spinning solvent becomes insufficient and spinning operability is impaired.

Although a dialkyl tin maleate polymer having a useful effect as described above, as described above, there is a disadvantage that the addition of the dialkyl tin maleate polymer impairs the transparency of the flame-retardant acrylic fiber. In the present invention, this drawback is to maintain the transparency of the flame-retardant acrylic fiber by allowing an organic acid to coexist with the dialkyltin maleate polymer.

Examples of these organic acids include dicarboxylic acids such as oxalic acid and citric acid or monocarboxylic acids such as tricarboxylic acid and acetic acid, and those having a plurality of carboxyl groups such as oxalic acid and citric acid are particularly effective and effective. Used. The addition amount of these organic acids is 0.4% by weight or more, preferably 0.6 to 2.0%.
% By weight.

The dialkyltin maleate polymer and the organic acid can be easily contained in the fiber of the present invention by adding necessary amounts when dissolving the polymer used in the fiber of the present invention in a solvent.

Furthermore, in order to improve the spinnability of the fiber of the present invention, it is necessary to attach a bisphenol A type water-soluble epoxy resin or the epoxy compound represented by the above formula (1) to the fiber surface in an amount of 0.2 to 1.5% by weight based on the fiber. is there. It is generally known that an epoxy compound has an effect of inactivating hydrochloric acid generated by a dehydrochlorination reaction by a chemical reaction. However, in the process of producing the fiber of the present invention, drying of the fiber,
It is necessary to perform wet heat relaxation treatment, and in the process of giving heat history to such fibers, easily reactive epoxy compounds are not only decomposed easily and cannot achieve the original purpose, but also discolor the fibers to pink Had the disadvantage of causing In the present invention, the disadvantage of such an epoxy compound can be solved by using a specific epoxy compound, and the fiber of the present invention can be imparted with rust-spinning properties.

The epoxy compound used in the present invention is a bisphenol A type water-soluble epoxy resin or the epoxy compound represented by the above formula (1). The object of the present invention can be achieved by adhering 0.2 to 1.5% by weight, preferably 0.5 to 1.0% by weight of these to the surface of the fiber. If the adhesion amount is less than 0.2% by weight, sufficient rusting property cannot be provided. Conversely, if the adhesion amount exceeds 1.5% by weight, a gum up phenomenon to a drying roll occurs in a fiber drying process, which causes a decrease in operability. .

As a method of attaching the epoxy compound to the fiber surface, a method of immersing the undried or dried fiber after stretching and washing in a dispersion liquid of the epoxy compound and then drying and fixing the same is mentioned. Is preferred. The temperature at which the epoxy compound is fixed to the fibers is effectively set in the range of 130 to 150 ° C.

Additives used in the fiber of the present invention include dialkyl tin maleate polymer, antimony trioxide, as long as it does not impair rustability, light stability, and transparency other than the organic acid. It is also possible to add a flame retardant auxiliary such as antimony pentoxide or other light stabilizers. As the solvent capable of dissolving the acrylonitrile polymer used in the present invention, preferably, an organic solvent such as dimethylacetamide, dimethylformamide, dimethylsulfoxide and the like can be mentioned. Inorganic salts, strong acid salts, acetone, and the like can be used as the solvent.

For the preparation of the spinning dope, the acrylonitrile-based polymer is dissolved in a solvent solution of 15 to 30% by weight for the purpose of ensuring the processability, and dissolved at a low temperature of 50 ° C. or less to avoid coloring by heat. It is usually preferable to disperse the dialkyl tin maleate polymer and the organic acid in a solvent before dissolving the acrylonitrile polymer. However, the dialkyl tin maleate polymer is 8 to 25% by weight, the organic acid is 4% by weight or more, and the necessary amount. A method of preparing a dispersion in which the acrylonitrile-based polymer is mixed and adding this to a solution of the acrylonitrile-based polymer solvent can be used for assembling a reasonable process.

The thus prepared spinning dope is discharged from a nozzle into a coagulation bath composed of a mixture of a solvent and water, and is shaped into an undrawn yarn.

The obtained unstretched yarn is stretched while washing away the solvent in the washing-stretching process, but it is preferable to set the stretching ratio in hot water as high as possible for spinning devitrification in the dyeing process. Usually, stretching in hot water is performed so as to be 50% of the maximum stretching ratio, soaking in an aqueous dispersion of the oil agent and the epoxy compound used in the present invention, drying, densification, and adhesion of the epoxy compound. If necessary, after the drying is completed, stretching can be performed again by heating to dryness.

The stretched and dried fibers are subjected to relaxation relaxation treatment under moist heat to obtain fibers having a balance of strength and elongation, and then cut into required lengths to obtain raw cotton for spinning. The fiber thus obtained is a flame-retardant acrylic fiber having excellent rust-proofing properties, light-stability, and transparency as compared with conventionally known chlorine-containing flame-retardant acrylic fibers.

<Example> Hereinafter, the present invention will be described in more detail with reference to examples.

 The evaluation methods in the examples are as follows.

The evaluation of flame retardancy is based on the oxygen index method (JIS K720-1A1), and the higher the LOI value, the higher the flame retardancy.

The specific viscosity of the polymer was measured at 25 ° C. in a 0.5 dimethylformamide solution.

The evaluation of the transparency of the fiber was performed by the light transmittance method shown below.

Cut the fiber treated with boiling water for 1 hour to a length of 30 mm,
5 g of freshly collected x 100 mm x 200 mm felt having a thickness of 1 mm is prepared by a needle punch method.

A 10 mm × 20 mm piece of felt, 50 mg in weight, is collected, placed in a 10 mm thick glass cell containing 5 ml of benzyl alcohol, and the transmittance at this time is measured using a spectrophotometer at a wavelength of 490.5 nm.

According to this method, a small amount of sample can be determined with good rust. Although the numerical value expressed as the transmittance% is small in absolute value, if the transmittance of the boiling water treated fiber is 40% or more, the transparency of the fiber is extremely good, and it is judged that the devitrification prevention property is sufficient.

Evaluation of light stability was performed by JI using a fade meter.
It was determined based on SL-1044.

 The evaluation of rust prevention was performed by the following method.

11 g of fully opened fiber is placed in a 200 cc beaker and covered. This is treated under a dry heat of 140 ° C. for 40 minutes. Insert 10 spun steel pins into the treated fiber, 63% RH,
Leave for 24 hours under constant temperature and humidity of 25 ° C. Take out the spun steel pins after standing, check the rusting status of each pin,
Points were awarded according to the degree. The points are a perfect score of 30 points, 30 points have no rust, 0 points are all rust,
The higher the point, the better the rust resistance.

The amount of the epoxy compound attached to the fiber surface was measured by the following method.

The fully opened raw cotton is treated with ethanol to extract the epoxy compound attached to the fiber surface. The epoxy in this extract is quantified by the hydrochloric acid-dioxane method (W eq / g
-Fibers). This value was divided by the epoxy equivalent (Eg / eq) of each epoxy compound to determine the amount of the epoxy compound attached to the fiber surface.

Example 1 A polymer composed of 58.5% by weight of acrylonitrile, 40% by weight of vinylidene chloride and 1.5% by weight of sodium methacrylsulfonate (specific viscosity 1.10), and a predetermined amount of dibutyltin maleate polymer and 0.8% by weight of citric acid based on the polymer Was dissolved in dimethylacetamide at 40 ° C. to obtain a spinning stock solution having a polymer concentration of 25% by weight. This spinning stock solution is spun into a 53% by weight dimethylacetamide-water mixture (30 ° C.) using a nozzle having a pore diameter of 0.076 mm, subjected to a solvent removal treatment, and then stretched 6-fold in hot water. And bisphenol A type water-soluble epoxy resin (Denacast EM-101, manufactured by Nagase Kasei Kogyo Co., Ltd.) is applied to the fiber by immersion in an aqueous dispersion continuously supplied so as to be 0.5% by weight with respect to the fiber, and then applied at 140 ° C.
And subjected to wet heat relaxation treatment to obtain 1.75 denier fiber.

This fiber was evaluated by the method described above, and the results are shown in Table 1.

Example 2 A polymer (specific viscosity: 1.10) consisting of 58.5% by weight of acrylonitrile, 40% by weight of vinylidene chloride and 1.5% by weight of sodium methacrylsulfonate, and 1.0% by weight of a dibutyltin maleate polymer and a predetermined amount of citric acid The acid was dissolved in dimethylacetamide at 40 ° C and the polymer concentration was 25
A weight percent spinning stock solution was obtained. This spinning stock solution has a pore size of 0.076 mm
Spun into a 53% by weight dimethylacetamide-water mixture (30 ° C.) using a nozzle, desolventized, stretched 6-fold in hot water, and used oil and bisphenol A type water-soluble epoxy The resin (Denacast EM-101, manufactured by Nagase Kasei Kogyo Co., Ltd.) is applied by immersion treatment in an aqueous dispersion continuously supplied so as to be 0.5% by weight with respect to the fiber.
The resultant was dried at ℃ and subjected to wet heat relaxation treatment to obtain 1.75 denier fiber.

This fiber was evaluated by the method described above, and the results are shown in Table 2.

Example 3 A polymer (specific viscosity: 1.10) consisting of 58.5% by weight of acrylonitrile, 40% by weight of vinylidene chloride and 1.5% by weight of sodium methacrylatesulfonate, and 1.0% by weight of a dioctyltin maleate polymer and 0.8% of citric acid Wt% in dimethylacetamide at 40 ° C and polymer concentration
A spinning dope of 25% by weight was obtained. This spinning stock solution has a pore size of 0.076m.
53% by weight of dimethylacetamide
After spinning out into a mixed solution of water (30 ° C.), subjecting it to a solvent removal treatment, it is stretched 6 times in hot water, and an oil agent and a bisphenol A type water-soluble epoxy resin (Denacast EM-101, manufactured by Nagase Kasei Kogyo Kogyo) are prepared. After being immersed in an aqueous dispersion continuously supplied so as to be 0.5% by weight with respect to the fiber and then applied, 14
The fiber was dried at 0 ° C. and subjected to wet heat relaxation treatment to obtain 1.75 denier fiber. (Experiment No.12) When this fiber was evaluated by the method described above, the rusting property was 30 points, the light stability was grade 4, and the transparency was high.
It was a flame-retardant acrylic fiber having a good quality of 48%, LOI30.

Example 4 A polymer composed of 58.5% by weight of acrylonitrile, 40% by weight of vinylidene chloride and 1.5% by weight of sodium methacrylsulfonate (specific viscosity 1.10), and 1.0% by weight of dibutyltin maleate polymer and 0.8% by weight of citric acid based on the polymer %
Was dissolved in dimethylacetamide at 40 ° C., and the polymer concentration was 25.
A weight percent spinning stock solution was obtained. This spinning stock solution has a pore size of 0.076 mm
Spun into a 53% by weight dimethylacetamide-water mixture (30 ° C.) using a nozzle, desolventized, stretched 6-fold in hot water, and used oil and bisphenol A type water-soluble epoxy The resin (Denacast EM-101, manufactured by Nagase Kasei Kogyo Co., Ltd.) is applied to the fiber by immersing the fiber in the amount shown in Table 3 in a continuously supplied aqueous dispersion, followed by drying at 140 ° C. and moist heat relaxation treatment. To give 1.75 denier fiber.

This fiber was evaluated by the method described above, and the results are shown in Table 3.

Example 5 A polymer composed of 58.5% by weight of acrylonitrile, 40% by weight of vinylidene chloride and 1.5% by weight of sodium methacrylsulfonate (specific viscosity: 1.10) and 1.0% by weight of dibutyltin maleate polymer and citric acid instead of this polymer 0.8% by weight each of oxalic acid, acetic acid and propionic acid were added to the solution, and dissolved in dimeracetamide at 40 ° C.
A weight percent spinning stock solution was obtained. This spinning stock solution has a pore size of 0.076 mm
Spun into a 53% by weight dimethylacetamide-water mixture (30 ° C.) using a nozzle, desolventized, stretched 6-fold in hot water, and used oil and bisphenol A type water-soluble epoxy The resin (Denacast EM-101, manufactured by Nagase Kasei Kogyo Co., Ltd.) is applied by immersion treatment in an aqueous dispersion continuously supplied so as to be 0.5% by weight with respect to the fiber.
The resultant was dried at ℃ and subjected to wet heat relaxation treatment to obtain 1.75 denier fiber.

This fiber was evaluated by the method described above, and the results are shown in Table 4.

Example 6 A polymer (specific viscosity: 1.10) consisting of 58.5% by weight of acrylonitrile, 40% by weight of vinylidene chloride and 1.5% by weight of sodium methacrylatesulfonate, and dibutyltin laurate, dibutyltin laurate, 1.0% by weight of normal octyltin mercaptite and 0.8% by weight of citric acid were added, and dissolved in dimeracetamide at 40 ° C. to obtain a spinning dope having a polymer concentration of 25% by weight. This spinning stock solution is spun into a 53% by weight dimethylacetamide-water mixture (30 ° C.) using a nozzle having a pore diameter of 0.076 mm, subjected to a solvent removal treatment, and then stretched 6-fold in hot water. And bisphenol A type water-soluble epoxy resin (Denacast EM-101, manufactured by Nagase Kasei Kogyo Co., Ltd.) is applied to the fiber by immersion in an aqueous dispersion continuously supplied so as to be 0.5% by weight with respect to the fiber, and then applied at 140 ° C. And subjected to wet heat relaxation treatment to obtain 1.75 denier fiber.

The fiber was evaluated by the method described above, and the results are shown in Table 5.

Example 7 A polymer composed of 58.5% by weight of acrylonitrile, 40% by weight of vinylidene chloride and 1.5% by weight of sodium methacrylatesulfonate (specific viscosity 1.10) and, based on this polymer, 1.0% by weight of dibutyltin maleate polymer and 0.8% by weight of citric acid %, Dissolved in dimethylacetamide at 40 ° C,
A spinning dope having a polymer concentration of 25% by weight was obtained. This spinning stock solution is spun into a 53% by weight dimethylacetamide-water mixture (30 ° C.) using a nozzle having a pore diameter of 0.076 mm, subjected to a solvent removal treatment, and then stretched 6-fold in hot water. Then, the epoxy compound shown in Table 6 was immersed in an aqueous dispersion continuously supplied so as to be 0.5% by weight with respect to the fiber, applied, dried at 140 ° C., and subjected to a wet heat relaxation treatment. A denier fiber was obtained.

The fiber was evaluated by the method described above, and the results are shown in Table 6.

<Effects of the Invention> The present invention has been conventionally considered as a problem with vinylidene chloride,
By improving the rusting problem of chlorine-containing acrylic fibers such as vinyl chloride, it is possible to provide flame-retardant acrylic fibers with excellent light stability and transparency, and the use as flame-retardant fibers has been expanded. It can respond to various requests related to improving the safety of the environmental environment.

Claims (1)

(57) [Claims] 1. A polymer comprising 45 to 70% by weight of acrylonitrile, 30 to 55% by weight of vinylidene chloride or vinyl chloride, 0.5 to 3% by weight of a monomer containing a sulfonic acid group and 0 to 5.5% by weight of an unsaturated monomer. A fiber comprising a polymer obtained by adding 0.8 to 2.5% by weight of a dialkyltin maleate polymer and 0.4% by weight or more of an organic acid, and further comprising a bisphenol A type water-soluble epoxy resin or A flame-retardant acrylonitrile fiber excellent in rust prevention, light stability and transparency, characterized in that the epoxy compound shown in (1) is adhered to the fiber at 0.2 to 1.5% by weight. Equation (1) Where a = 1.6, b = 4.4, R = alkyl group