JP4527118B2 - Method for producing elastic fiber having high elastic modulus, alkali resistance and heat resistance - Google Patents

Abstract

Disclosed herein is a process for preparing an elastic fiber having a high modulus and superior resistance to alkali and heat. The process comprises the steps of adding 1~20% by weight of a cellulose acetate to a polyurethane or polyurethaneurea solution, based on the total weight of the polyurethane or polyurethaneurea, homogeneously stirring the mixture to obtain a spinning solution, and ripening and spinning the solution. According to the process, a high modulus and highly heat resistant elastic fiber can be prepared without a sudden change in conditions for preparation of the polymer.

Description

  The present invention relates to a method for producing an elastic fiber having a high elastic modulus and excellent alkali resistance and heat resistance. More specifically, the present invention provides a spinning solution by adding cellulose acetate to a polyurethane or polyurethane urea solution in an amount of 1 to 20% by weight based on the total weight of the polyurethane or polyurethane urea, and ripens the solution. And a method of producing an elastic fiber having a high elastic modulus and high alkali resistance and heat resistance by spinning and spinning. According to this method, an elastic fiber having a high elastic modulus and high heat resistance can be produced without abruptly changing the production conditions of the polymer.

  Elastic fibers are used in a wide variety of applications. For example, the elastic fibers work together with the polyester fibers to hold the polyester yarn of the three-way warp velvet fabric firmly. Such elastic fibers have a high enough modulus to form and maintain a good fluffing condition and at the same time heat resistant enough to withstand high temperature dyeing and curing processes in the subsequent post-treatment stage of polyester velvet fabric It is necessary to show gender. Recently, embossing technology has attracted attention as a technology for increasing the added value of velvet fabric. In order to emboss various patterns, it is necessary to burn-out and print the fluffed yarn of the velvet fabric to the desired color. In such a process, the elastic fiber inevitably needs to have excellent alkali resistance. Specifically, a high-concentration alkaline solution (for example, mainly caustic soda solution) is used for the purpose of dissolving the fluffed polyester yarn at the desired site in such a burning-out process, and after the printing solution is added thereto. Since high temperature treatment is performed for the purpose of fixing the dye, such an elastic fiber needs to have excellent alkali resistance so as not to be deteriorated by an alkaline solution remaining in a high temperature state on the cloth.

  The problems often encountered when trying to produce velvet fabric using common elastic fibers are as follows. Since the elastic modulus of a general elastic fiber is low, a phenomenon in which the velvet effect exhibited by the elastic fiber is inferior when the fluffed yarn becomes flat after shearing occurs. In addition, such elastic fibers lose their inherent elastic recovery because of the high post-treatment temperature, causing the fabric to spread and, in extreme cases, to break the elastic fibers. In particular, when the concentration of the alkaline solution used in the embossing technique that requires burning out and printing is high and the heat treatment temperature is high, the elastic fibers are severely broken, resulting in a large number of holes in the velvet cloth.

  Because of such problems, velvet fabric manufacturers require elastic fiber manufacturers to have elastic fibers with high elastic modulus and high heat resistance. In addition, manufacturers of velvet fabrics that have been burned out and printed require not only excellent alkali resistance but also the supply of elastic fibers with high elastic modulus and excellent heat resistance.

  The most common method employed by elastic fiber manufacturers to solve the above-mentioned problems is to increase the content of hard segments and side chains contained in the polymer solution for producing elastic fibers. Without the use of a chain extender with high binding power. The elastic modulus of the elastic fiber increases as the hard segment content increases. When a chain extender is used, the heat resistance of the elastic fiber is improved. However, since such a process is difficult in terms of managing the viscosity of the polymer solution, the physical properties of the elastic fiber produced using such a polymer solution are not uniform, and the small scale of such elastic fiber. It is not appropriate when a simple manufacturing is required. On the other hand, elastic fibers have some degree of alkali resistance due to their inherent properties. However, high concentrations of caustic soda of about 25% to about 30% can be easily degraded when added at high temperatures such as 160 ° C to 180 ° C. Therefore, the burning-out process and the printing process are performed separately. To date, no technology has been established that allows the burning-out process and the printing process to proceed simultaneously.

  Therefore, in this technical field, a method suitable for easily producing an elastic fiber having a high elastic modulus and excellent heat resistance and alkali resistance without any problems associated with non-uniform physical properties is required. .

  A polyurethane elastic fiber having improved moisture absorption characteristics and biodegradability is disclosed in Japanese Patent Publication No. 2000-303259 by Fujibo. According to the publication, cellulose acetate is added to a polyurethane or polyurethaneurea solution, and the mixture is uniformly stirred to obtain a spinning solution, which is spun to produce an acetylcellulose-containing elastic fiber, and said acetylcellulose A polyurethane elastic fiber is produced by treating the contained elastic fiber with an alkali. However, this publication does not mention that the elastic fiber exhibits alkali resistance or heat resistance. In addition, the elastic modulus of the elastic fiber is too low to solve the above-mentioned problems.

  The inventors have intensively and intensively studied to solve the above-mentioned problems, and as a result, acetic acid (diacetic acid or triacetic acid) having a degree of acetylation of about 28% to about 72% in the polymer solution. ) Add 1 to 20% by weight of cellulose based on the solid content of the polymer solution (ie polymer component), and stir the mixture uniformly to obtain a spinning solution, which can be determined in advance. When the aged solution is spun and the aged solution is spun, an elastic fiber having a high elastic modulus and excellent heat resistance and alkali resistance has a sudden change in polymerization viscosity, and the physical properties of the fiber product become non-uniform. And found that it can be easily manufactured. The present invention is based on this.

  Accordingly, an object of the present invention is to provide a method for producing an elastic fiber having a high elastic modulus and excellent heat resistance and alkali resistance under mild process conditions.

  According to one aspect of the present invention, there is provided a method for producing an elastic fiber, which comprises adding 1 to 20% by weight of cellulose acetate to a polyurethane or polyurethane urea solution based on the total weight of the polyurethane or polyurethane urea. Obtaining a spinning solution, aging the solution for a predetermined time, and spinning the aged solution.

  According to another aspect of the present invention, there is provided an elastic fiber having a high elastic modulus, high alkali resistance and high heat resistance, produced by the present method.

  Hereinafter, the present invention will be described in more detail.

  A polyurethane or polyurethaneurea solution suitable for use in the present invention is obtained using procedures known in the art. For example, a polyurethane precursor is produced by reacting an organic diisocyanate with a high molecular weight diol. After the polyurethane precursor is dissolved in an organic solvent, the resulting precursor solution is reacted with diamine to extend the chain. By stopping the chain extension reaction using monoamine, a polyurethane or polyurethaneurea solution is obtained.

  Examples of the organic diisocyanate that can be used in the present invention include diphenylmethane-4,4'-diisocyanate, hexamethylene diisocyanate, toluene diisocyanate, butylene diisocyanate, hydrogenated p, p-methylene diisocyanate and the like. As the high molecular weight diol, for example, polytetramethylene ether glycol, polypropylene glycol or polycarbonate diol may be used, and the number average molecular weight of all of them is preferably 1,750 to 2,050. On the other hand, the diamine used as the chain extender may be ethylene diamine, propylene diamine, hydrazine or the like, and the monoamine used as the chain terminator may be diethylamine, monoethanolamine, dimethylamine or the like. Examples of suitable organic solvents that can be used for the purpose of obtaining the polymer solution include, but are not limited to, N, N′-dimethylformamide, N, N′-dimethylacetamide, dimethyl sulfoxide. Etc. are included.

If necessary selected, the polyurethane or polyurethaneurea solution, further clouding agent (dulling agents), UV stabilizers, antioxidants, NO _x gas anti-yellowing agents, anti-adherents, a dye enhancer and anti-chlorine agents At least one additive may be added.

  According to the method of the present invention, 1 to 20% by weight of the cellulose acetate is added to the polyurethane or polyurethane urea solution based on the total weight of the polymer, and then the mixture is stirred uniformly to obtain a spinning solution. If the amount of cellulose acetate added is less than 1% by weight, the effect of addition becomes negligible. On the other hand, when the amount of cellulose acetate exceeds 20% by weight, uniform mixing becomes difficult. The cellulose acetate may be cellulose diacetate or cellulose triacetate, preferably having a degree of acetylation of about 28% to about 72%. The spinning solution is allowed to stand at 30 ° C. to 70 ° C. for 28 to 38 hours for aging, and then spun to produce a final elastic fiber having a high elastic modulus and excellent heat resistance and alkali resistance. According to the research conducted by the present inventors, the formation of urethane bonds, urea bonds, and hydrogen bonds between the polymer and cellulose acetate by uniformly stirring and aging the cellulose acetate as an additive and the polymer solution. Such a step directly affects the improvement of the elastic modulus and the improvement of alkali resistance and heat resistance of the elastic yarn. Therefore, it is important to set optimum conditions for the above-mentioned stage. According to the method of the present invention, the cellulose acetate is dissolved in the same organic solvent used for the purpose of obtaining the polymer solution, and the resulting solution is stirred uniformly for 7 to 8 hours. Add the solution to the polymer solution. The resulting mixture is then stirred uniformly for at least 2 hours. At this point, the percentage of cellulose acetate added is increased and the stirring time is extended for 30 minutes. After stirring, the mixture of cellulose acetate and polymer solution is aged for about 28 to 38 hours, and then spun through a spinning nozzle to produce a final elastic fiber.

  The configuration and effects of the present invention will be described in more detail with reference to the following specific examples and comparative examples. However, the examples are given for illustrative purposes and should not be construed as limiting the scope of the invention.

Example 1
By using 518 g of diphenylmethane-4,4′-diisocyanate and 2,328 g of polytetramethylene ether glycol having a number average molecular weight of 1,800, and reacting them with each other at 85 ° C. for 90 minutes, A polyurethane precursor containing both terminal positions was produced. The polyurethane precursor was cooled to room temperature and then dissolved in 4,643 g of N, N′-dimethylacetamide to obtain a polyurethane precursor solution. Thereafter, 54 g of propylenediamine and 9.1 g of diethylamine were dissolved in 1,889 g of N, N′-dimethylacetamide, and the resulting solution was added to the polyurethane precursor solution at 10 ° C. A modified polyurethaneurea solution was produced.

UV stabilizers to the polymer solution, antioxidants, NO _x gas anti-yellowing agents, dyeing accelerators were added fogging agent anti-adherents and titanium based magnesium group. The resulting solution was stirred uniformly. To this homogeneous solution was added a solution formed by adding 1% by weight of cellulose diacetate having a degree of acetylation of 45% to N, N′-dimethylacetamide based on the solid content of the polymer solution. Thereafter, the mixture was degassed for 2 hours and then aged at 40 ° C. for 35 hours to obtain a spinning solution. This spinning solution was subjected to dry spinning at a spinning temperature of 250 ° C. and stretched at a stretch ratio of 1.3 to produce polyurethaneurea elastic fibers having a thickness of 40 denier. The polyurethaneurea elastic fiber thus produced was wound up.

  A velvet fabric was produced by using 590 polyurethaneurea elastic fibers as warp yarns, knitting with 50 denier polyester yarn, and dyeing. The velvet fabric was subjected to a burning out and printing process. The yarn of the velvet fabric was subjected to measurements on heat resistance and alkali resistance, and the velvet fabric was subjected to measurements on force retention. In addition, the fuzzy state of the fabric before undergoing burning out and the holes produced in the fabric after undergoing burning out were also evaluated. The results are shown in Table 1.

(Example 2)
A solution formed by adding 5% by weight of cellulose diacetate (degree of acetylation: 45%) in N, N′-dimethylacetamide based on the solid content of the polymer solution is added to the polymer solution, A polyurethaneurea elastic fiber having a thickness of 40 denier was produced and wound up in the same manner as shown in Example 1 except that uniform stirring was carried out for 4 hours. A velvet fabric was then produced in the same manner as shown in Example 1 before it was burned out and printed. The properties of this velvet fabric were measured and evaluated and the results are shown in Table 1.

(Example 3)
A solution formed by adding 10% by weight of cellulose diacetate (degree of acetylation: 45%) in N, N′-dimethylacetamide based on the solid content of the polymer solution is added to the polymer solution, A polyurethaneurea elastic fiber having a thickness of 40 denier was produced and wound up in the same manner as shown in Example 1 except that uniform stirring was carried out for 6.5 hours. A velvet fabric was then produced in the same manner as shown in Example 1 before it was burned out and printed. The properties of this velvet fabric were measured and evaluated and the results are shown in Table 1.

Example 4
A solution formed by adding 15% by weight of cellulose diacetate (degree of acetylation: 45%) to N, N′-dimethylacetamide based on the solid content of the polymer solution is added to the polymer solution, A polyurethaneurea elastic fiber having a thickness of 40 denier was produced and wound up in the same manner as shown in Example 1 except that uniform stirring was carried out for 9.5 hours. A velvet fabric was then produced in the same manner as shown in Example 1 before it was burned out and printed. The properties of this velvet fabric were measured and evaluated and the results are shown in Table 1.

(Example 5)
A solution formed by adding 20% by weight of cellulose diacetate (acetylation degree: 45%) to N, N′-dimethylacetamide based on the solid content of the polymer solution is added to the polymer solution, A polyurethaneurea elastic fiber having a thickness of 40 denier was produced and wound in the same manner as shown in Example 1 except that uniform stirring was carried out for 12 hours. A velvet fabric was then produced in the same manner as shown in Example 1 before it was burned out and printed. The properties of this velvet fabric were measured and evaluated and the results are shown in Table 1.

(Example 6)
After cellulose triacetate (degree of acetylation: 65%) was dissolved in N, N′-dimethylacetamide at 110 ° C. over 30 minutes, the resulting solution was added to the polymer solution in the amount of cellulose triacetate. Was added in an amount of 1% by weight based on the solid content of the polymer solution, and the thickness was 40 denier in the same manner as shown in Example 1 except that uniform stirring was performed for 2 hours. A polyurethaneurea elastic fiber was produced and wound. A velvet fabric was then produced in the same manner as shown in Example 1 before it was burned out and printed. The properties of this velvet fabric were measured and evaluated and the results are shown in Table 1.

(Example 7)
After cellulose triacetate (degree of acetylation: 65%) was dissolved in N, N′-dimethylacetamide at 110 ° C. over 30 minutes, the resulting solution was added to the polymer solution in the amount of cellulose triacetate. Is added in an amount of 5% by weight based on the solid content of the polymer solution, and the thickness is 40 denier in the same manner as shown in Example 1 except that uniform stirring is performed for 2 hours. A polyurethaneurea elastic fiber was produced and wound. A velvet fabric was then produced in the same manner as shown in Example 1 before it was burned out and printed. The properties of this velvet fabric were measured and evaluated and the results are shown in Table 1.

(Example 8)
After cellulose triacetate (degree of acetylation: 65%) was dissolved in N, N′-dimethylacetamide at 110 ° C. over 30 minutes, the resulting solution was added to the polymer solution in the amount of cellulose triacetate. Is added in an amount of 10% by weight based on the solid content of the polymer solution, and the thickness is 40 denier in the same manner as shown in Example 1 except that uniform stirring is performed for 2 hours. A polyurethaneurea elastic fiber was produced and wound. A velvet fabric was then produced in the same manner as shown in Example 1 before it was burned out and printed. The properties of this velvet fabric were measured and evaluated, and the results are shown in Table 1.

Example 9
After cellulose triacetate (degree of acetylation: 65%) was dissolved in N, N′-dimethylacetamide at 110 ° C. over 30 minutes, the resulting solution was added to the polymer solution in the amount of cellulose triacetate. Is added in an amount of 15% by weight based on the solid content of the polymer solution, and the thickness is 40 deniers in the same manner as shown in Example 1 except that uniform stirring is performed for 2 hours. A polyurethaneurea elastic fiber was produced and wound. A velvet fabric was then produced in the same manner as shown in Example 1 before it was burned out and printed. The properties of this velvet fabric were measured and evaluated and the results are shown in Table 1.

(Example 10)
After cellulose triacetate (degree of acetylation: 65%) was dissolved in N, N′-dimethylacetamide at 110 ° C. over 30 minutes, the resulting solution was added to the polymer solution in the amount of cellulose triacetate. Is added in an amount of 20% by weight based on the solid content of the polymer solution, and the thickness is 40 denier in the same manner as shown in Example 1 except that uniform stirring is performed for 2 hours. A polyurethaneurea elastic fiber was produced and wound. A velvet fabric was then produced in the same manner as shown in Example 1 before it was burned out and printed. The properties of this velvet fabric were measured and evaluated and the results are shown in Table 1.

(Comparative Example 1)
A solution formed by adding 25% by weight of cellulose diacetate (degree of acetylation: 45%) in N, N′-dimethylacetamide based on the solid content of the polymer solution is added to the polymer solution, A polyurethaneurea elastic fiber having a thickness of 40 denier was produced and wound up in the same manner as shown in Example 1 except that uniform stirring was carried out for 9.5 hours. A velvet fabric was then produced in the same manner as shown in Example 1 before it was burned out and printed. The properties of this velvet fabric were measured and evaluated, and the results are shown in Table 1.

(Comparative Example 2)
After cellulose triacetate (degree of acetylation: 65%) was dissolved in N, N′-dimethylacetamide at 110 ° C. over 30 minutes, the resulting solution was added to the polymer solution in the amount of cellulose triacetate. Is added in an amount of 25% by weight based on the solid content of the polymer solution, and the thickness is 40 denier in the same manner as shown in Example 1 except that uniform stirring is performed for 2 hours. A polyurethaneurea elastic fiber was produced and wound. A velvet fabric was then produced in the same manner as shown in Example 1 before it was burned out and printed. The properties of this velvet fabric were measured and evaluated, and the results are shown in Table 1.

(Comparative Example 3)
A polyurethaneurea elastic fiber having a thickness of 40 denier was produced and wound up in the same manner as shown in Example 1 except that cellulose diacetate was not added. A velvet fabric was then produced in the same manner as shown in Example 1 before it was burned out and printed. The properties of this velvet fabric were measured and evaluated and the results are shown in Table 1.

note:
1) The heat resistance exhibited by the yarn was evaluated by the following procedure: the yarn sample was stretched 100% and subjected to a wet heat treatment at 130 ° C. for 1 hour. The heat treatment is repeated 5 times (5 cycles). The heat resistance of the yarn sample is expressed as a percentage difference between the length of the yarn sample before heat treatment (“initial length”) and the length after the fifth cycle (“download value”).

    2) The alkali resistance exhibited by the yarn was evaluated by the following procedure: the yarn sample was immersed in a 25% (25% by weight) aqueous NaOH solution and heated to 150 ° C. The alkali resistance of the yarn sample is expressed as the time required for the decomposition of the yarn sample.

    3) The force retention of the fabric was evaluated by the following procedure: The fabric that had undergone the final treatment was cut to produce a fabric sample (1 inch x 30 cm). This fabric sample was obtained from Instron Co. Hold the measurement cloth sample so that the length of the measurement cloth sample is 20 cm. This holding is repeated 5 times (5 cycles). The difference between the length after the fabric sample is subjected to the first cycle ("upload value") and the length after the fifth cycle ("download value") to hold the force of the fabric sample Expressed as a percentage of

    4) In the evaluation of the fluffing state before burning out, the evaluation was performed by visually inspecting the uprightness of the fluffy thread after the velvet cloth was subjected to shearing and background dyeing. When the fuzzy thread was straight and upright, the fuzzy state was judged to be “O”. On the other hand, when several fuzzy yarns were flattened, the state was judged to be “Δ”.

    5) A hole formed in the cloth after being burned out was evaluated by visual inspection.

    As shown in Table 1, since the polymerization and spinning viscosity can be uniformly controlled by using the method of the present invention, such elastic fibers have uniform physical properties, high elastic modulus, improved heat resistance and Shows improved alkali resistance. Therefore, when the method of the present invention is applied to a general velvet cloth or a special velvet cloth that requires continuous burning out and printing, the elastic fiber does not deteriorate and the condition of the fluffy yarn and cloth is reduced. The advantage of being kept stable is obtained.

  While preferred embodiments of the invention have been disclosed for purposes of illustration, those skilled in the art will recognize that various modifications, additions and modifications may be made without departing from the scope and spirit of the invention as disclosed in the appended claims. It will be understood that substitutions can be made.

Claims (7)

A method for producing an elastic fiber, comprising:
Adding 1-20% by weight of cellulose acetate to the polyurethane or polyurethaneurea solution, based on the total weight of the polyurethane or polyurethaneurea, and stirring the mixture uniformly for at least 2 hours to obtain a spinning solution;
Aging the spinning solution by leaving it at 30 ° C. to 70 ° C. for 28 to 38 hours , and spinning the aged solution;
A method comprising steps.   The method according to claim 1, wherein the cellulose acetate is cellulose diacetate or cellulose triacetate having an acetylation degree of 28% to 72%.   The polyurethane or polyurethane urea solution reacts an organic diisocyanate with a high molecular weight diol to form a polyurethane precursor, the polyurethane precursor is dissolved in an organic solvent, and the precursor solution is sequentially reacted with a diamine and a monoamine. The method according to claim 1 or 2, wherein the solution is obtained as described above.   The organic diisocyanate is selected from the group consisting of diphenylmethane-4,4′-diisocyanate, hexamethylene diisocyanate, toluene diisocyanate, butylene diisocyanate and hydrogenated p, p-methylene diisocyanate, and the high molecular weight diol is polytetramethylene ether glycol, polypropylene Selected from the group consisting of glycol and polycarbonate diol, said diamine selected from the group consisting of ethylenediamine, propylenediamine and hydrazine, and said monoamine selected from the group consisting of diethylamine, monoethanolamine and dimethylamine, and said organic solvent From the group consisting of N, N′-dimethylformamide, N, N′-dimethylacetamide and dimethylsulfoxide The method of claim 3 wherein the-option. Further clouding agent to the spinning solution, UV stabilizers, antioxidants, NO _x gas anti-yellowing agents, anti-adherents, at least one additive selected from the dye enhancer and anti-chlorine agents also add claim 1 or 2. The method according to 2.   The elastic fiber made by the method of Claim 1 or 2. The velvet cloth manufactured using the elastic fiber of Claim 6 .