TWI508982B - A method for fabricating a flame retardant modified pan and a flame retardant fiber - Google Patents

Description

Method for producing high flame retardant modified polyacrylonitrile, and flame retardant fiber

The invention relates to a method for producing polyacrylonitrile, and a flame-retardant fiber, in particular to a method for producing a high flame-retardant modified polyacrylonitrile, and a flame-retardant fiber containing the high flame-retardant modified polyacrylonitrile.

With the advancement of society, the construction of cities and the textiles used by the people are increasing. However, the fire caused by the burning of textiles is also one of the common disasters, causing serious losses and personnel safety. Therefore, in order to protect the safety of life and property, all over the world In the 1960s, the flame retardant requirements for textiles were put forward, and relevant standards and regulations were formulated. With the development of international trade, entertainment industry, national defense construction, public fire protection and labor safety, the demand for flame retardant textiles, Both in number and variety.

The value of the limiting oxygen index (LOI) of the fiber is theoretically as long as it exceeds 21%, and it has a self-extinguishing effect in the air. However, in the event of a fire, the effect of air convection and relative humidity is caused by the high temperature. The oxygen limit index LOI sometimes needs to exceed 27% to achieve self-extinguishing effect.

At present, the commonly used fiber flame retardant methods can be roughly divided into: (1) fiber reforming flame retardant, and reactive monomers containing functional groups such as phosphorus, sulfur, halogen, etc., by bonding to a macromolecular chain to achieve durability The flame retardant effect, or the introduction of an aromatic ring or an aromatic heterocyclic ring in the polymer to increase the rigidity of the molecular chain to improve the thermal stability of the fiber, or to crosslink the polymer into a three-dimensional structure, to improve the difficulty of carbon chain fracture, or The polymer is placed in high temperature air to initiate dehydrogenation and cyclization to form a ladder structure, increase the thermal cracking temperature, inhibit the generation of combustible gas, (2) blend flame retardant, and add flame retardant, such as zinc borate. , ammonium polyphosphate, Al(OH) ₃ , Mg(OH) ₂ , Sb ₂ O ₃ , Sb ₂ O ₅ , nano clay, etc. to the spinning solution to increase the flame retardancy of the fiber, this method It has little effect on fiber properties, but it may have an effect on the flame retardant effect as the number of washings increases. (3) After-treatment flame retardant, the fiber is incinerated by post-processing. The common method is dipping. , coating method, spray method, etc., the flame retardant used is aromatic Phosphate ester, halogenated aliphatic phosphate, and polyphosphate urethane.

In the case of acrylic yarns which are currently common, the stability to sunlight and the atmosphere is good, the stability to chemical agents is good, the dyeability is good, the color is bright, and the softness and warmth are similar to wool. It also has the name of synthetic wool. Only the acrylic fiber itself has poor flame retardancy. Its Oxygen limit index is only 18%, which is the lowest among synthetic fibers. Therefore, the modified polyacrylonitrile flame retardant fiber will be It is hoped that in addition to the original advantages of the above acrylic fiber, the flame retardant effect can be further improved.

However, in the manner of fiber-modified flame retardant preparation of modacrylic flame retardant fibers, it is easy to add new comonomers during the polymerization because of the addition of new comonomers in the polymerization monomer. The influence of the base, resulting in the inclusion of the yield, the molecular weight of the polymerization, the post-treatment after polymerization, etc. The nature is also affected, especially the methylsulfonyl olefinic monomers commonly used to improve the dyeability and devitrification of acrylic fibers. Due to their large active chain transfer, the polymerization reaction is inhibited and the polymer is formed. The degree of polymerization becomes small, and therefore, the characteristics of the fiber are seriously affected. In order to improve the aforementioned problems, for example, JP 2761097 B is a selection of a sulfonic acid-containing olefinic monomer, and a methylpropane sulfonate and a 2-propenyl oxime-2-methylpropane sulfonate are used ( The combination of 2-Acrylamide-2-methylpropanesulfonate) improves the problem of using methylsulfonate-based monomers, while US Pat. No. 4,513,126 utilizes the selection, content ratio, and process of sulfonic acid-containing olefinic monomers. Control, improve the influence of the sulfonic acid-containing olefinic monomer on the polymerization, and prepare a flame-retardant fiber having high flame retardancy, good dyeability and low devitrification problem.

However, the aforementioned polymerization reaction is not as simple as the polymerization of acrylonitrile, and the reaction rate is also affected. In addition, the simultaneous polymerization of a plurality of monomers must have a relatively high technical threshold. Therefore, how to simplify the modified polymerization The production process of acrylonitrile, which produces modacrylic fiber with high flame retardancy, good dyeability and low devitrification problem, is one of the directions improved by those skilled in the art.

Therefore, the object of the present invention is to provide a method for preparing a highly flame-retardant modified polyacrylonitrile comprising:

(a) pre-polymerizing an A composition to obtain a first prepolymer solution containing a modified polyacrylonitrile having an average molecular weight of from 30,000 to 40,000, wherein the A composition comprises acrylonitrile, a vinyl halide-containing single a body, at least one hydrophilic ethylenic monomer, a polar solvent, and a reaction initiator. The halogenated B The monomer of the olefin contains at least vinylidene chloride, and the weight percentage of the A composition is 100% by weight, the weight percentage of the vinylidene chloride is 10 to 40% by weight, and the weight percentage of the hydrophilic olefin monomer is 5 to 50% by weight, and the weight ratio of the acrylonitrile to the vinylidene chloride is between 2 and 3.5.

(b) pre-polymerizing a B component to obtain a second prepolymer solution containing a modified polyacrylonitrile having an average molecular weight of from 30,000 to 40,000, wherein the B composition comprises acrylonitrile, a vinyl halide-containing single a polar solvent, and a reaction initiator, wherein the vinyl halide-containing monomer contains at least vinylidene chloride, and the weight percentage of the vinylidene chloride is 100% by weight of the B composition. Between 60 and 40% by weight.

(c) mixing the first and second prepolymer solutions to obtain a mixed liquid containing a high flame retardant modified polyacrylonitrile, wherein the high flame retardant modified polyacrylonitrile has an average molecular weight of not more than 80000, and the content of the vinylidene chloride, the content of the acrylonitrile, the vinyl halide-containing monomer, and the hydrophilic ethylenic monomer of the high flame retardant modified polyacrylonitrile component is 100% by weight, and the content of the vinylidene chloride is 30 Between 100% by weight and 50% by weight, the content of the hydrophilic ethylenic monomer is between 1 and 5% by weight, and the content of the acrylonitrile is not less than 55% by weight.

Preferably, the method for preparing the high flame-retardant modified polyacrylonitrile, wherein the polymerization temperature of the A and B compositions in the steps (a) and (b) is between 20 and 70 °C.

Preferably, in the preparation method of the high flame-retardant modified polyacrylonitrile, in the step (c), the first and second prepolymer solutions are mixed in a weight ratio of between 0.1 and 10.

Preferably, the preparation method of the high flame retardant modified polyacrylonitrile is as described above. And a hydrophilic ethylenic monomer selected from the group consisting of an ethylenic monomer having a sulfonic acid group and a salt derivative such as sodium, potassium, ammonium or a quaternary amine salt, and a carboxylic acid. An acid olefin monomer and a salt derivative thereof such as sodium, potassium, ammonium or amine salt, and a combination thereof.

Preferably, the method for preparing the high flame retardant modified polyacrylonitrile, wherein the A composition further comprises a chromaticity inhibitor.

Preferably, the method for preparing the high flame-retardant modified polyacrylonitrile further comprises a step (d) of removing the solvent and the unreacted monomer of the mixed solution to the modified polypropylene in the mixed liquid. The weight percentage of nitrile is between 20 and 35 wt%.

Further, another object of the present invention is to provide a method for preparing a highly resistive modified polyacrylonitrile comprising:

(a) pre-polymerizing an A composition to obtain a first prepolymer solution containing a modified polyacrylonitrile having an average molecular weight of 70,000 to 80,000, wherein the A composition comprises acrylonitrile, a halogenated ethylene-containing monomer, a polar solvent, at least one hydrophilic ethylenic monomer, and a reaction initiator, the vinyl halide-containing monomer containing at least vinylidene chloride, and the weight percentage of the A composition is 100% by weight, and the vinylidene chloride is The weight percentage is 10 to 40% by weight, the hydrophilic ethylenic monomer is 5 to 50% by weight, and the weight ratio of acrylonitrile to vinylidene chloride is between 2 and 3.5.

(b) pre-polymerizing a B component to obtain a second prepolymer solution containing a modified polyacrylonitrile having an average molecular weight of 50,000 to 60,000, wherein the B composition comprises acrylonitrile, a halogenated ethylene-containing monomer, a polar solvent, and a reaction initiator, wherein the vinyl halide-containing monomer contains at least Partially dichloroethylene, and the weight percentage of the vinylidene chloride is between 60 and 40% by weight based on 100% by weight of the B composition.

(c) blending the first and second prepolymer solutions to obtain a mixed liquid containing a highly flame-retardant modified polyacrylonitrile, wherein the high flame retardant modified polyacrylonitrile has an average molecular weight of 50,000 Up to 80,000, the content of the vinylidene chloride is 30% by weight based on 100% by weight of the acrylonitrile, the vinyl halide-containing monomer, and the hydrophilic ethylenic monomer of the high flame retardant modified polyacrylonitrile component. Between 100% by weight and 50% by weight, the content of the hydrophilic ethylenic monomer is between 1 and 5% by weight, and the content of the acrylonitrile is not less than 55% by weight.

Preferably, the method for preparing the high flame-retardant modified polyacrylonitrile, wherein the polymerization temperature of the A and B compositions in the steps (a) and (b) is between 20 and 70 °C.

Preferably, in the preparation method of the high flame-retardant modified polyacrylonitrile, in the step (c), the first and second prepolymer solutions are mixed in a weight ratio of between 0.1 and 10.

Preferably, the method for preparing the high flame-retardant modified polyacrylonitrile, wherein the hydrophilic ethylenic monomer is selected from the group consisting of an ethylenic monomer having a sulfonic acid group and sodium, potassium, ammonium, and a quaternary ammonium salt thereof a salt derivative, a carboxylic acid based monomer, and a salt derivative such as a sodium, potassium, ammonium or amine salt thereof, and a combination thereof.

Preferably, the method for preparing the high flame retardant modified polyacrylonitrile, wherein the A composition further comprises a chromaticity inhibitor.

Preferably, the method for preparing the high flame-retardant modified polyacrylonitrile further comprises a step (d) of removing the solvent and the unreacted single of the mixed solution. The weight percentage of the modified polyacrylonitrile in the mixture is between 20 and 35 wt%.

Still another object of the present invention is to provide a flame retardant fiber comprising a modacrylic fiber, and the modacrylic fiber is prepared from the aforementioned high flame retardant modacrylic fiber. The high flame-retardant modified polyacrylonitrile obtained by the method is obtained by spinning, and the flame-retardant fiber has an oxygen limited index of more than 27.

Preferably, the aforementioned flame retardant fiber further comprises a natural fiber or a chemical fiber.

Preferably, the flame retardant fiber further comprises a flame retardant, and the flame retardant may be selected from the group consisting of antimony pentoxide (Sb ₂ O ₅ ), antimony trioxide (Sb ₂ O ₃ ), and aluminum hydroxide (Al). (OH) ₃ ), magnesium hydroxide (Mg(OH) ₂ ), and one of the foregoing combinations.

The effect of the invention lies in that a continuous homogeneous solution polymerization or blending method is employed, that is, a highly flame-retardant modified polyacrylonitrile which meets the requirements of different uses can be produced in an optimized manner.

The high flame retardant modified polyacrylonitrile of the invention can be obtained by copolymerization or blending, and the high flame retardant modified polyacrylonitrile having an average molecular weight of not more than 80,000 is made by using the high flame retardant modified polyacrylonitrile. The oxygen-limited index of the hard-to-burn fiber is not less than 27.

The first method for preparing the high flame retardant modified polyacrylonitrile of the invention A preferred embodiment is described by taking the high flame-retardant modified polyacrylonitrile by copolymerization.

The first preferred embodiment of the method for preparing a highly flame-retardant modified polyacrylonitrile of the present invention comprises the following three steps.

In step (a), an A composition is prepolymerized to obtain a first prepolymer solution containing a modified polyacrylonitrile having an average molecular weight of between 35,000 and 40,000.

Specifically, the step (a) is to dissolve the acrylonitrile (hereinafter referred to as AN), the halogen-containing vinyl monomer, the dyeing auxiliary, and the reaction initiator in a predetermined ratio in a predetermined ratio. The polymerization is carried out in an amount of a polar solvent under the conditions of a polymerization temperature of 20 to 70 ° C and a polymerization pH of pH 5 to pH 13.

Specifically, the A composition includes acrylonitrile, a halongen-containing vinyl monomer, a hydrophilic ethylenic monomer, a polar solvent, and a reaction initiator. The vinyl halide-containing monomer comprises at least vinylidene chloride. Specifically, the vinyl halide-containing monomer may further comprise vinyl chloride (VCM), vinylidene chloride (hereinafter referred to as VDC), a halogenated olefin-containing monomer such as vinyl bromide (VBM) or vinylidene bromide (VDB). And in order to make the obtained modacrylic acid have excellent flame retardant properties, the weight percentage of the vinyl halide-containing monomer is 10 to 40% by weight based on 100% by weight of the A composition.

The hydrophilic ethylenic monomer may be selected from a sulfonic acid group-containing ethylenic monomer and a salt derivative thereof such as sodium, potassium, ammonium or a quaternary amine salt, for example, sodium methallyl sulfonate. , hereinafter referred to as SMAS), 2-Sodium 2-Acrylamide-2-methylpro sulfonate (hereinafter referred to as SAMPS), sodium styrene sulfonate (Sodium Styrene Sulfonate, hereinafter referred to as SSS) ), Sodium allyl sulfonate (SAS), carboxylic acid olefinic monomers and their salt derivatives such as sodium, potassium, ammonium, amine salts, such as Methacrylic acid, acrylic acid (acrylic acid) and itaconic acid, the hydrophilicity of the A composition can be increased by the addition of the hydrophilic ethylenic monomer, and the dyeability of the modified polyacrylonitrile can be improved. Among them, the sulfonic acid group-containing olefinic monomer and derivative, since the sulfonic acid group can impart dyeability and hydrophilicity to the synthetic fiber, a suitable sulfonic acid group-containing hydrophilic olefinic monomer can be obtained. The modified polyacrylonitrile can be solidified to form a dense fiber during the wet spinning process, thereby preventing the devitrification of the produced fiber; however, if the sulfonic acid group content is too high, the The hydrophilicity is too good, but the unevenness of the condensate will cause pores, which will devitrify the produced fiber. Therefore, the weight percentage of the hydrophilic olefinic monomer is 100% by weight of the A composition. 5 to 50% by weight.

The solvent is selected from organic solvents such as dimethylformamide, dimethylacetamide, dimethylhydrazine, and may contain a small amount of water (less than 0.5%).

The reaction initiator can be selected from the group consisting of azo Starting agent, for example: azobisisobutyronitrile (AIBN), azobis dimethyl valeronitrile (AVN), or a peroxygen initiator, for example: peroxidation Di(2-ethylhexyl) peroxy dicarbonate, 1,2-dimethylperoxy 2,2-dimethylperoxypropionate (t-butyl peroxypivalate and ), peroxidic lauryl peroxide.

In addition, the A composition may further comprise a chroma inhibitor for inhibiting yellowing of the modified polyacrylonitrile, and a recombination inhibitor for controlling the reaction rate and the molecular weight, and the chroma inhibitor may be selected from malic acid. And a salt thereof, the recombination inhibitor may be selected from the group consisting of hydroquinone (HQ), 4-methoxyphenol (MEHQ), isopropanol, or mercaptan. Compound.

Next, step (b) is a prepolymerization of a B composition to obtain a second prepolymer solution containing a modified polyacrylonitrile having an average molecular weight of from 35,000 to 40,000.

Specifically, the step (b) is: dissolving the acrylonitrile, the vinylidene halide-containing monomer, and the reaction initiator in a predetermined ratio in a predetermined amount of a polar solvent at a polymerization temperature of 20 to 70 ° C. The polymerization reaction is carried out under the conditions of pH 5 to pH 13 for the polymerization reaction.

In more detail, the B composition comprises acrylonitrile, a vinyl halide-containing monomer, a polar solvent, and a reaction initiator, wherein the vinyl halide-containing monomer contains at least vinylidene chloride and is composed of the B. The weight percentage is 100% by weight, and the weight percentage of the vinylidene chloride is 60 to 40 wt%, and other, for example, the vinyl halide-containing monomer, the polar solvent, and the reaction initiator are substantially the same as those of the aforementioned step (a), and therefore will not be further described.

Next, step (c) is carried out, the first and second prepolymer solutions are mixed at a weight ratio of 0.1 to 10, copolymerized, and the average molecular weight of the modified polyacrylonitrile obtained by copolymerization is not more than 80000, a mixed liquid containing the high flame retardant modified polyacrylonitrile can be obtained, wherein the high flame retardant modified polyacrylonitrile has an average molecular weight of not more than 80,000, and the vinylidene chloride content is between 30 Between 50% by weight.

A second preferred embodiment of the preparation method of the high flame-retardant modified polyacrylonitrile of the present invention is described by taking the high flame-retardant modified polyacrylonitrile by a blending method as an example.

The preparation step of the second preferred embodiment is substantially the same as the preparation method of the first preferred embodiment, except that in the second preferred embodiment, the step (a) is to control the first prepolymer solution. The average molecular weight of the modified polyacrylonitrile is between 70,000 and 80,000, and the step (b) is to control the average molecular weight of the modified polyacrylonitrile in the second prepolymer solution to be between 50,000 and 60,000. The first and second prepolymer solutions are blended to obtain a mixed solution containing a modified polyacrylonitrile having an average molecular weight of from 50,000 to 80,000.

The modified polyacrylonitrile mixture prepared in the first and second preferred embodiments may further comprise a step (d). The step (d) is to remove the solvent of the mixed solution after evaporation (defoaming) by using a thin film evaporator, so that the weight percentage of the modified polyacrylonitrile in the mixed solution is between 20 and 35 Between wt%, a spinning dope is obtained, and the spinning dope can be used for wet spinning to obtain a flame retardant fiber having good flame resistance and strength.

It should be noted that the above-mentioned flame-retardant fiber may not only contain the modified polyacrylonitrile fiber obtained by spinning the modified polyacrylonitrile obtained by the preparation method of the modified polyacrylonitrile of the present invention, but also Further co-spinning with other natural fibers or chemical fibers such as cotton, acrylic fibers, nylon, etc., different types of flame retardant fibers are obtained.

In addition, the flame retardant fiber may also comprise a flame retardant, which may be selected from the group consisting of antimony pentoxide (Sb ₂ O ₅ ), antimony trioxide (Sb ₂ O ₃ ), and aluminum hydroxide (Al (OH). ₃ ) magnesium hydroxide (Mg(OH) ₂ ), and one of the foregoing combinations to further increase the flame resistance of the flame retardant fiber.

The present invention utilizes a batch type reaction, and firstly combines a hydrophilic and dyeable A composition with a flame retardant B composition to obtain a first and a second prepolymer, and then according to the demand. The first and second prepolymers are mixed or mixed for the second polymerization, so that it is possible to avoid the conventional use of a single polymerization method because at the same time, a plurality of reaction monomers exist, which affect the reaction rate and increase the reaction complexity. Not only is it easier to control the process, but also the complexity of the reaction can be reduced. In addition, different polyacrylonitriles of different compositions can be obtained by using different blending ratios, so that it can be more conveniently applied to products for different purposes.

In order to more clearly illustrate the preparation of the modified polyacrylonitrile of the present invention, the following specific examples and comparative examples are described, wherein the specific examples 1 to 5 and the comparative examples 1 to 2 are prepared by copolymerization. Polyacrylonitrile, specific examples 6 to 10 and comparative examples 3 to 5 were prepared by blending The modified polyacrylonitrile, and the specific examples 11 to 18 illustrate that the modified polyacrylonitrile obtained by the specific example 2 is added with different content of the flame retardant to obtain a modacrylic fiber, and then the modification is performed. The polyacrylonitrile fibers are co-spun with different amounts of natural fibers (cotton) to produce flame retardant fibers; however, the examples are merely illustrative of the invention, and the scope of the invention is not limited by these specific examples. .

Specific example 1

Composition A: AN, VDC, SMAS, and AVN were dissolved in dimethylformamide to form a first mixed liquid, wherein the first mixed liquid contained 460 ppm of AVN, and the weight ratio of AN/VDC/SMAS was 65. /20/15, and the total weight of AN/VDC/SMAS is 35% of the weight of the first mixture. Then, the reaction is carried out for 17 hours under the conditions of a reaction temperature of 45 ° C and a pH of 7.5, and the average molecular weight of the polymerization is controlled to be from 35,000 to 40,000, thereby obtaining a first pre-modified polyacrylonitrile having an average molecular weight of from 35,000 to 40,000. Polymer solution.

Composition B: AN, VDC, and AVN were dissolved in dimethylformamide to form a second mixed solution, wherein the second mixed liquid contained 460 ppm of AVN, and the weight ratio of AN/VDC/ was 55/45. And the total weight of the AN/VDC accounts for 50% of the weight of the first mixture. Subsequently, the reaction was carried out for 15 hours under the conditions of a reaction temperature of 45 ° C and a pH of 7.5 to obtain a second prepolymer solution containing a modified polyacrylonitrile having an average molecular weight of from 35,000 to 40,000.

Copolymerization: the first and second prepolymer solutions were mixed at a weight ratio of 1:3, and then about 800 ppm of AVN was added, and the reaction was continued at 50 ° C for 10 hours to obtain a modified polypropylene having an average molecular weight of 61,000. Nitrile mixture Mix liquid.

Spinning: The mixture is evaporated through a thin film evaporator so that the solid weight (PC) of the modified polyacrylonitrile in the mixture is 26% by weight to obtain a spinning dope, and the spinning dope is When the wet spinning method is stretched three times, and dried and stretched twice at 100 ° C, the modified polyacrylonitrile fiber can be obtained, and the modified polyacrylonitrile fiber composition is 56.4% AN, 40.1% VDC, 3.5% SMAS with an average molecular weight of 61,000.

Specific example 2

The preparation of this specific example 2 is substantially the same as that of the specific example 1, except that the hydrophilic ethylenic monomer SMAS is replaced by SAMPS, and the polymerization time of the first mixed solution is 15 hours, and the modified polycondensation after copolymerization The average molecular weight of acrylonitrile was 68,000, and the composition of the modacrylic fiber was 56.1% AN, 40.1% VDC, 3.8% SAMPS, and the average molecular weight was 68,000.

Specific example 3

The preparation of the specific example 3 is substantially the same as that of the specific example 1, except that the dyeing assistant SMAS is replaced by SSS, and the polymerization time of the first mixed solution is 15 hours, and the average of the modified polyacrylonitrile after copolymerization is obtained. The molecular weight was 66,000, and the spinning dope had a solid content of 27% by weight, and the modacrylic fiber composition was 55.5% AN, 41.2% VDC, 3.3% SSS, and the average molecular weight was 66,000.

Concrete example 4

Composition A: AN, VDC, SAMPS, and AVN were dissolved in dimethylformamide to form a first mixed liquid, wherein the first mixed liquid contained 460 ppm of AVN, and the weight ratio of AN/VDC/SAMPS was 58. /27/15, And the total weight of the AN/VDC/SAMPS is 35% of the weight of the first mixture. Then, the reaction is carried out for 10 hours under the conditions of a reaction temperature of 45 ° C and a pH of 7.5, and the average molecular weight of the polymerization is controlled to be from 35,000 to 40,000, thereby obtaining a first pre-modified polyacrylonitrile having an average molecular weight of from 35,000 to 40,000. Polymer solution.

Composition B: AN, VDC, and AVN were dissolved in dimethylformamide to form a second mixed solution, wherein the second mixed liquid contained 460 ppm of AVN, and the weight ratio of AN/VDC/ was 55/45. And the total weight of the AN/VDC accounts for 50% of the weight of the first mixture. Subsequently, the reaction was carried out for 10 hours under the conditions of a reaction temperature of 45 ° C and a pH of 7.5 to obtain a second prepolymer solution containing a modified polyacrylonitrile having an average molecular weight of from 35,000 to 40,000.

Copolymerization: the first and second prepolymer solutions were mixed at a weight ratio of 1:3, and then about 800 ppm of AVN was added, and the reaction was continued at 50 ° C for 10 hours to obtain a modified polypropylene having an average molecular weight of 62,000. A mixture of nitriles.

Spinning: The mixture is evaporated through a thin film evaporator, so that the solid content (PC) of the modified polyacrylonitrile in the mixture is 28 wt%, a spinning dope is obtained, and the spinning dope is wet-spun. When the silk method is stretched three times, and dried and stretched twice at 100 ° C, the modacrylic fiber can be obtained. The modacrylic fiber composition is 55.5% AN, 44.5% VDC, 3.0% SAMPS. The average molecular weight MW is 62,000.

Concrete example 5

The preparation method of the specific example 5 is substantially the same as that of the specific example 4, except that the weight ratio of the AN/VDC/SAMPS in the composition A is 70/20/10. And the polymerization time of the first mixed liquid is 15 hours, the average molecular weight of the modified polyacrylonitrile after copolymerization is 61000, and the composition of the modified polyacrylonitrile fiber is 57.2% AN, 40.0% VDC, 2.8% SAMPS, average The molecular weight is 61000.

Specific example 6

Composition A: AN, VDC, SAMPS, and AVN were dissolved in dimethylformamide to form a first mixed liquid, wherein the first mixed liquid contained 600 ppm of AVN, and the weight ratio of AN/VDC/SAMPS was 65. /27/8, and the total weight of AN/VDC/SAMPS is 40% of the weight of the first mixture. Then, the reaction is carried out for 14 hours under the conditions of a reaction temperature of 53 ° C and a pH of 7.5, and the average molecular weight of the polymerization is controlled to be 70,000 to 80,000, thereby obtaining a first pre-modified polyacrylonitrile having an average molecular weight of 70,000 to 80,000. Polymer solution.

Composition B: AN, VDC, and AVN were dissolved in dimethylformamide to form a second mixed liquid, wherein the second mixed liquid contained 800 ppm of AVN, and the weight ratio of AN/VDC/ was 55/45. And the total weight of the AN/VDC accounts for 50% of the weight of the first mixture. Subsequently, the reaction was carried out for 16 hours under the conditions of a reaction temperature of 53 ° C and a pH of 7.5 to obtain a second prepolymer solution containing a modified polyacrylonitrile having an average molecular weight of from 50,000 to 60,000.

Blending: The first and second prepolymer solutions are mixed in a weight ratio of 1:3 to obtain a mixed solution of a modified polyacrylonitrile having a viscosity average molecular weight of 58,000.

It should be noted that the aforementioned Viscosity-average Molecular Weight is obtained by measuring the mixed modified polyacrylonitrile. The viscosity of the mixture is mixed, and the viscosity is converted into a viscosity average molecular weight. The measurement method of the viscosity average molecular weight is explained below.

First, the relative viscosity of a DMF solution containing 0.5% of the blended modified polyacrylonitrile was measured using a Ubbe lohde (ASTM D445-64) three-way viscometer at 20 °C. Among them, the polymer DMF solution seconds / DMF solvent seconds is equal to the relative viscosity (η rel) (20 ° C constant temperature, falling ball viscosity).

The measured relative viscosity can be converted to the relative molecular weight (viscosity average molecular weight) by using the following conversion formula: [(η rel(20°C)/1.0275)-1]x70670=viscosity average molecular weight (30°C)

Spinning: The mixture is evaporated through a thin film evaporator, so that the solid content (PC) of the modified polyacrylonitrile in the mixture is 28 wt%, a spinning dope is obtained, and the spinning dope is wet-spun. When the silk method is stretched 3 times and dried and dried at 100 ° C for 2 times, the modacrylic fiber can be obtained. The modacrylic fiber composition is 56.3% AN, 40.7% VDC, 3.0% SAMPS. .

Specific example 7

The preparation of the specific example 7 is substantially the same as that of the specific example 6, except that the weight ratio of the AN/VDC/SAMPS of the composition A is 65/25/10, and the viscosity of the blended modified polyacrylonitrile is The molecular weight was 59,000, and the modacrylic fiber composition was 56.2% AN, 40.1% VDC, 3.7% SAMPS.

Concrete example 8

The preparation of this specific example 8 is substantially the same as that of the specific example 6, and the difference is The weight ratio of AN/VDC/SAMPS of the composition A is 63/25/12, the viscosity average molecular weight of the blended modified polyacrylonitrile is 61000, and the composition of the modified polyacrylonitrile fiber is 55.6%. AN, 40.1% VDC, 4.3% SAMPS.

Concrete example 9

The preparation of this specific example 9 is substantially the same as that of the specific example 6, except that the weight ratio of the AN/VDC/SAMPS of the composition A is 65/25/10, and the first and second prepolymer solutions are 1: The weight ratio of 2.5 was blended, and the viscosity of the modified polyacrylonitrile obtained after blending was 58,000, and the composition of the modified polyacrylonitrile fiber was 56.1% AN, 39.5% VDC, and 4.4% SAMPS.

Specific Example 10

The preparation of this specific example 9 is substantially the same as that of the specific example 6, except that the weight ratio of the AN/VDC/SAMPS of the composition A is 65/25/10, and the first and second prepolymer solutions are 1: The weight ratio of 2 was blended, and the viscosity of the modified polyacrylonitrile obtained after blending was 58,000, and the composition of the modified polyacrylonitrile fiber was 56.1% AN, 39.5% VDC, and 4.4% SAMPS.

Comparative example 1

The preparation of Comparative Example 1 was substantially the same as that of the specific example 4, except that the weight ratio of the AN/VDC/SAMPS of the composition A was 65/20/15, and the polymerization time of the first mixed liquid was 10 hours. The weight ratio of AN/VDC of B is 40/60 and the average molecular weight of the modified polyacrylonitrile after copolymerization is 58000, and the composition of the modified polyacrylonitrile fiber is 44.7% AN, 51.2% VDC, 4.1% SAMPS.

Comparative example 2

The preparation of Comparative Example 2 was substantially the same as that of Comparative Example 1, except that the weight ratio of AN/VDC of the composition B was 30/70, and the average molecular weight of the modified polyacrylonitrile after copolymerization was 58,000, and The modacrylic fiber composition was 36.8% AN, 59.1% VDC, 4.1% SAMPS.

Comparative example 3

The preparation of Comparative Example 3 was substantially the same as that of the specific example 6, except that the weight ratio of the AN/VDC/SAMPS of the composition A was 60/20/20, and the average molecular weight of the modified polyacrylonitrile after blending was In 61000, the spinning dope of Comparative Example 3 had a total elongation of 5 times in wet spinning, and the spinning property was poor.

Comparative example 4

The preparation of Comparative Example 4 was substantially the same as that of the specific example 6, except that the weight ratio of the AN/VDC/SAMPS of the composition A was 80/10/10, and the weight ratio of the AN/VDC of the composition B was 50/50. The average molecular weight of the modified polyacrylonitrile after blending was 61,000, and the spinning dope of Comparative Example 4 was 5 times as long as the wet spinning total, and the spinnability was poor.

Comparative Example 5

The preparation of Comparative Example 5 was substantially the same as that of the specific example 6, except that the weight ratio of the AN/VDC/SAMPS of the composition A was 90/0/10, and the weight ratio of the AN/VDC of the composition B was 50/50. The average molecular weight of the modified polyacrylonitrile after blending was 60,000, and the spinning dope of Comparative Example 5 was 5 times as long as the wet spinning total, and the spinnability was poor.

Next, the specific examples 1 to 10 and the comparative example 1 described above are respectively respectively The modacrylic fibers prepared to 5 were tested for denier, elongation, strength, LOI, and whiteness values.

Measurement method description: Limitation of oxygen index (LOI): Measuring machine: Burning tester (ON-2M, Suga Test Instruments Co.Ltd.)

1. Take the fiber sliver 0.35g and roll it into a strip sample.

2. Nitrogen and oxygen feed mixing

3. Place the strip sample into the burner and adjust the proportional flow of nitrogen (N ₂ ) and oxygen (O ₂ ).

4. The strip sample is ignited until the flame disappears, and the flow ratio of O ₂ /(N ₂ +O ₂ ) is the LOI value.

Stretch measurement: measuring machine: strength extension tester (West Germany TEXCHNO FAVIMAT +)

Strength measurement: measuring machine: strength and elongation tester (West Germany TEXCHNO FAVIMAT +)

1. Take a single fiber of 20mm, and hang the specified load clamp at one end, and pull it off with a strong tensile tester. The force of the moment of breaking is divided by the fineness, that is, the strength (g/deniner).

Saturated staining measurement: 0.6 g of malachite green dye (Malachite green), add 0.5 ml of glacial acetic acid, stir well, then dissolve with hot water (about 60 to 70 ° C) Dilute to 1000 ml and prepare a malachite green dye solution (stock solution) at a concentration of 0.6 (g-dye/l).

A clean flask was taken and 150 g of malachite green dye solution was weighed into the flask.

3.00g cotton sample was weighed and placed in a flask weighing the dye solution (bath ratio 1:50, concentration in OWF%: (0.6/1000)*150/3*100=3% OWF) to 96 The temperature was dyed at °C for 120 minutes, and then heated at 100 °C for 20 minutes.

After the dyeing is completed, the residual liquid and the stock solution in the bottle are diluted with a certain ratio after cooling, and the absorbance of the solution is measured at a wavelength of 616 nm using a spectrophotometer (Hitachi u-3010).

The residual liquid absorbance is A, and the stock solution absorbance is B, then the saturation value (R) = [(B-A) / B] * 3% O.W.F.

BaiDu:

1. Take about 1.2 g of cotton-uniformed fibers and measure the whiteness value directly with a color difference meter.

Color difference meter instrument: Tokyo Electrochromic TC1800MC II

Spinning property: It is estimated by an optical microscope (Nikon MM-40) to "primary fiber pores" after stretching and "stretching after stretching", and is divided into five levels:

Level 1: Indicates that the spinning is extremely poor and cannot be condensed

Level 2: At least two items are clearly below the Level 5 standard, indicating poor spinnability.

Level 3: At least one item is clearly below the level 5 standard, indicating spinning Sexually ordinary.

Level 4: At least one is close to but not at level 5, indicating good spinnability:

Level 5: Fiber elongation > 32%, strength > 3.2 g / d, no holes, indicating excellent spinnability.

Feel: It is judged by human touch and is divided into 5 levels:

1 means that the hand feel is very poor, and the touch is sensational and rough.

2 indicates that the hand feel is poor, and the touch is sensational and rough.

3 means that the feel is normal.

4 means good hand feeling, judged by softness and smoothness.

5 means excellent hand feeling, judged by softness and smoothness.

The composition ratios of the specific examples 1 to 10 and the comparative examples 1 to 5 and related test results are summarized in Table 1.

Specific examples 11 to 14

The preparation of the specific examples 11 to 14 is substantially the same as that of the specific example 2, except that 10% of Sb ₂ O ₅ is first added to the spinning dope and then spun to obtain a modacrylic fiber. The modacrylic fiber was further blended with 0%, 30%, 50%, 70% cotton to obtain a flame retardant fiber.

Specific examples 15 to 16

The preparation of the specific examples 15 to 16 was substantially the same as that of the specific example 2, except that 5% and 8% of Sb ₂ O ₅ were added to the spinning dope, followed by wire-drawing, and the obtained flame-retardant fiber was obtained.

Next, the flame-retardant fibers obtained in the specific examples 11 to 16 were subjected to the measurement of the number of oxygen-limiting fingers, and the results of the oxygen-limiting fingers of the flame-retardant fibers of the specific examples 11 to 16 were summarized in Table 2.

Specific examples 17 to 19

The reaction conditions of the specific examples 17 to 19 were the same as those of the specific example 2. different The specific examples 17 to 18 are respectively added to the spinning dope by adding 8 wt% of Sb2O5, and then adding 3 wt% and 6 wt% of Al(OH)3, respectively; and the specific example 19 is added to the spinning dope. 10 wt% of Sb2O5 and 3 wt% of Al(OH)3.

The spinning stock solutions of the specific examples 17 to 19 were spun and drawn into fibers, and the flame retardant effects obtained by blending with different amounts of cotton were as shown in Table 3.

In summary, the present invention utilizes a batch-type reaction to first pre-polymerize a composition having hydrophilicity and dyeability with a B composition having flame retardancy to obtain first and second pre-polymerizations having a predetermined molecular weight. After the material, the first and second prepolymers are blended or mixed, and then subjected to the second polymerization, which not only solves the defects of poor dyeing degree and devitrification when the flame-retardant acrylic fiber is conventionally produced. Moreover, the manufacturing method of the present invention can also avoid the problem of affecting the reaction rate and increasing the complexity of the reaction due to the presence of multiple reactive monomers at the same time; in addition, the first and second prepolymers are twice subjected to different mixing ratios. The modified polyacrylonitrile of different compositions can be obtained by processing, so that it can be more conveniently applied to products for different purposes. The flame retardant fiber obtained by spinning the modified polyacrylonitrile obtained by the preparation method of the invention In addition to having high flame retardancy, it also has properties such as spinnability, strength, elongation, and dyeability, so that the object of the present invention can be achieved.

The above is only the preferred embodiment of the present invention, and the scope of the present invention is not limited thereto, that is, the simple equivalent changes and modifications made by the patent application scope and patent specification content of the present invention, Are still within the scope of the patent of the present invention.

Claims (15)

A preparation method of high flame-retardant modified polyacrylonitrile comprises: (a) pre-polymerizing an A composition to obtain a first prepolymer solution containing a modified polyacrylonitrile having an average molecular weight of 30,000 to 40,000 Wherein the A composition comprises acrylonitrile, a vinyl halide-containing monomer, a hydrophilic ethylenic monomer, a polar solvent, and a reaction initiator, the vinyl halide-containing monomer comprising at least vinylidene chloride, and the A The weight percentage of the composition is 100% by weight, the weight percentage of the vinylidene chloride is 10 to 40% by weight, the weight percentage of the hydrophilic ethylenic monomer is 5 to 50% by weight, and the weight ratio of acrylonitrile to vinylidene chloride Between 2 and 3.5; (b) pre-polymerizing a B component to obtain a second prepolymer solution containing a modified polyacrylonitrile having an average molecular weight of from 30,000 to 40,000, wherein the B composition comprises An acrylonitrile, a vinyl halide-containing monomer, a polar solvent, and a reaction initiator, wherein the vinyl halide-containing monomer contains at least vinylidene chloride, and the weight percentage of the B composition is 100% by weight. The weight percentage of dichloroethylene is 60 to 40% by weight; and (c) The first and second prepolymer solutions are mixed and copolymerized to obtain a mixed liquid containing a high flame retardant modified polyacrylonitrile, wherein the high flame retardant modified polyacrylonitrile has an average molecular weight of not more than 80,000, and The high flame-retardant modified polyacrylonitrile component has an acrylonitrile, a vinyl halide-containing monomer, and a hydrophilic ethylenic monomer in a weight percentage of 100% by weight, and the vinylidene chloride content is 30 to 50% by weight. Inter-, hydrophilic olefinic monomer The content is 1 to 5 wt%, and the content of acrylonitrile is not less than 55 wt%. The method for preparing a highly flame-retardant modified polyacrylonitrile according to claim 1, wherein the prepolymerization temperature of the composition of the A and B in the steps (a) and (b) is between 20 and 70 °C. The method for preparing a highly flame-retardant modified polyacrylonitrile according to claim 1, wherein in the step (c), the weight ratio of the first and second prepolymer solutions is between 0.1 and 10. The method for preparing a highly flame-retardant modified polyacrylonitrile according to claim 1, wherein the hydrophilic ethylenic monomer is selected from the group consisting of an ethylenic monomer having a sulfonic acid group and sodium, potassium, ammonium, and a quaternary ammonium salt thereof. a salt derivative, a carboxylic acid based monomer, and a salt derivative such as a sodium, potassium, ammonium or amine salt thereof, and a combination thereof. The method for preparing a highly flame-retardant modified polyacrylonitrile according to claim 1, wherein the A composition further comprises a chromaticity inhibitor. The method for preparing a high flame retardant modified polyacrylonitrile according to claim 1, further comprising a step (d) of removing the solvent of the mixed solution to a high flame retardant modified polyacrylonitrile in the mixed solution. The weight percentage is between 20 and 35 wt%. A method for preparing a high flame retardant modified polyacrylonitrile comprises: (a) prepolymerizing an A composition to obtain a first prepolymer solution containing a modified polyacrylonitrile having an average molecular weight of 70,000 to 80,000, wherein The A composition comprises acrylonitrile, a vinyl halide-containing monomer, a polar solvent, at least one hydrophilic ethylenic monomer, and a reaction initiator, the vinyl halide-containing monomer containing at least vinylidene chloride, and the A Composition weight The percentage by weight is 100% by weight, the weight percentage of the vinylidene chloride is 10 to 40% by weight, the weight percentage of the hydrophilic ethylenic monomer is 5 to 50% by weight, and the weight ratio of acrylonitrile to vinylidene chloride is 2 Up to 3.5; (b) pre-polymerizing a B component to obtain a second prepolymer solution containing a modified polyacrylonitrile having an average molecular weight of 50,000 to 60,000, wherein the B composition comprises acrylonitrile, vinyl halide-containing a monomer, a polar solvent, and a reaction initiator, wherein the vinyl halide-containing monomer contains at least vinylidene chloride, and the weight percentage of the vinylidene chloride is 100% by weight based on the weight of the B composition. 60 to 40% by weight; and (c) blending the first and second prepolymer solutions to obtain a mixed liquid containing a highly flame-retardant modified polyacrylonitrile, wherein the high flame retardant modified polypropylene The average molecular weight of the nitrile is between 50,000 and 80,000, and the weight percentage of the acrylonitrile, the vinyl halide-containing monomer, and the hydrophilic ethylenic monomer of the high flame retardant modified polyacrylonitrile component is 100% by weight. The content of vinyl chloride is between 30 and 50% by weight, and the content of hydrophilic ethylenic monomer is from 1 to 5 wt%, and the content of acrylonitrile is not less than 55 wt%. The method for preparing a high flame retardant modified polyacrylonitrile according to claim 7, wherein the prepolymerization temperature of the composition of the A and B in the steps (a) and (b) is between 20 and 70 °C. The method for preparing a highly flame-retardant modified polyacrylonitrile according to claim 7, wherein in the step (c), the weight ratio of the first and second prepolymer solutions is between 0.1 and 10. The method for preparing a highly flame-retardant modified polyacrylonitrile according to claim 7, wherein the hydrophilic ethylenic monomer is selected from the group consisting of an ethylenic monomer having a sulfonic acid group and sodium, potassium, ammonium, and a quaternary ammonium salt thereof. a salt derivative, a carboxylic acid based monomer, and a salt derivative such as a sodium, potassium, ammonium or amine salt thereof, and a combination thereof. The method for preparing a highly flame-retardant modified polyacrylonitrile according to claim 7, wherein the A composition further comprises a chromaticity inhibitor. The method for preparing a high flame retardant modified polyacrylonitrile according to claim 7, further comprising a step (d) of removing the solvent of the mixed solution until the weight percentage of the modified polyacrylonitrile in the mixed solution is From 20 to 35 wt%. A flame retardant fiber comprising a modacrylic fiber, and the modacrylic fiber is a high flame retardant modification prepared by the preparation method of the high flame retardant modified polyacrylonitrile according to claim 1. The polyacrylonitrile is obtained by spinning and has an oxygen limited index of more than 27. The flame retardant fiber of claim 13 further comprising a natural fiber or a chemical fiber. The flame retardant fiber according to claim 13, further comprising a flame retardant selected from the group consisting of antimony pentoxide (Sb ₂ O ₅ ), antimony trioxide (Sb ₂ O ₃ ), and aluminum hydroxide. (Al(OH) ₃ ), magnesium hydroxide (Mg(OH) ₂ ), and one of the foregoing combinations.