KR100384094B1 - A process for producing polymeric products for polyurethane elastic fibers, and elastic fibers produced from the polymeric products - Google Patents

Abstract

The present invention uses a homogeneous mixer using poly (tetramethylene ether) glycol and methylene-bis (4-phenylisocyanate) with a reaction molar ratio of glycol: diisocyanate as 1: (1.4 to 1.55). To react with stirring to prepare a primary polymer, and a mixture of 93 to 98 mol% ethylene diamine, 2 to 7 mol% 1,2-diaminopropane and 0.2 to 0.8 mol% diethyltriamine was used as a chain extender. When used as, it is characterized in that the polymerization with the primary polymer, to produce an elastic fiber through dry spinning using the polymer.

Polyurethane elastic yarn produced according to the present invention is excellent in viscosity stability and excellent heat resistance, and is very suitable as a relative elastic yarn of the knitting and circular knitted fabrics with polyester fibers requiring a high temperature dyeing process.

Description

A process for producing polymeric products for polyurethane elastic fibers, and elastic fibers produced from the polymeric products}

The present invention relates to a method for producing a polyurethane elastic fiber excellent in viscosity stability and heat resistance while maintaining the inherent physical properties of the elastic fiber. Polyurethane-based elastic fibers are called spandex or elastane, and have excellent elastic modulus and elasticity. They are widely used in stockings, sports clothes, women's underwear, swimwear and stretch fabrics, and do not require elasticity like suits. Their use continues to expand, for example, by adding a small amount to textiles and exposing new textures.

In the case of elastic fibers, it is mainly used mixed with other materials such as nylon or polyester fibers, rather than being used alone, and when mixed and used as in polyester / elastic fiber circular knitted fabrics, due to relatively poor heat resistance When the high temperature heat treatment process is performed at about 130 ° C, the elastic fibers are damaged and the elasticity is decreased or trimming may occur. Due to these drawbacks, it is difficult to expand various uses of elastic fibers.

Generally known elastic fiber manufacturing method is as follows. Prepared by reacting polyether glycol with methylene-bis (4-phenylisocyanate), diluting the isocyanate endblocking product with solvent, then chain extending with diamine and spinning it.

Important in this manufacturing process is excellent quality and economical efficiency, particularly important in economics is to increase the concentration and spinning rate of the final polymer. However, the higher the concentration of the final polymer, the lower the viscosity stability, the lower the uniformity of the yarn, and the higher the spinning speed, the higher the yarn uniformity as well as the damage in terms of elongation.

Therefore, it is essential to consider productivity in developing a manufacturing method of elastic fibers, and various studies have been made on a manufacturing method capable of high concentration and high speed spinning while maintaining quality.

U.S. Patent No. 5,362,432 (name of invention: Spandex Dry Spinning Process) uses ethylene diamine as chain extender and 8-17 mole percent 1,2-diaminopropane in the total diamine mixture as auxiliary chain extender. The manufacturing method of the spandex company which enables the high-speed spinning of 900m / min is described.

The problem of the above patent is that the heat-setting efficiency is excellent, but the heat resistance is relatively low, and when subjected to a high temperature dyeing process, the inherent properties of the elastic yarn fabric, the elongation, elastic recovery rate is lowered wear life is lowered. This is because 1,2-diaminopropane, which is used as an auxiliary chain extender in the synthesis of linear polyurethane polymers, has some bulky radicals, which weakens the crystal structure inside the polyurethane polymer and thereby heat-setting This is because the heat-setting efficiency is increased by being easily thermally deformed during the treatment process, but it causes crystal abnormality in the crystal structure inside the polymer to lower the elastic recovery rate.

As a prior patent which prevented weakening of a crystal structure using triamines, Unexamined-Japanese-Patent No. 4-100919 (The name of invention: The manufacturing method of the polyurethane elastic yarn insoluble in the organic solvent) is mentioned. In the embodiment of this patent, only ethylene diamine is used as the chain extender and triamine, tetraamine, pentraamines are used after the polymerization reaction and before the spinning process to prepare a polymer insoluble in an organic solvent. It is described that a polyurethane elastic yarn is insoluble in an organic solvent. At this time, it is described that triamines use 0.18 weight% based on the weight of a tetrapolymer.

In the above patent, triamines can be added without the use of an auxiliary chain extender to prevent weakening of the crystal structure and to achieve excellent heat resistance. Inferiority of the yarn and poor uniformity of the yarn.

Patents that increase the viscosity stability and prevent the weakening of the crystal structure include Korean Patent Publication No. 98-29659 (name of the invention: an improved method for producing a polymer for polyurethane fibers). This patent uses ethylene diamine as a chain extender and 19-25 mole% 1,2-diaminopropane in the total diamine mixture as auxiliary chain extender to increase viscosity stability, Techniques for preventing the weakening of the crystal structure by the use of 1,2-diaminopropane are described using 0.2 to 0.8 mole% of diethylenetriamine forming the secondary structure.

Although the above-mentioned prior art has solved the viscosity stability and the weakening of the crystal structure to some extent, this also has a weakness in terms of heat resistance due to excessive use of 1,2-diaminopropane as in US Pat. No. 5,362,432. In the high temperature dyeing process of 130 ° C. or higher, the elastic yarn is trimmed or damaged, thereby lowering the strength originally possessed.

An object of the present invention is to solve the problems of the prior art as described above, to maintain the viscosity stability of 36% or more high-density polyurethane polymer and to maintain the uniformity and elongation of the yarn even at high speed spinning of more than 900m / min and heat resistance It is to provide a method for producing excellent elastic yarn.

In the present invention, 1,2-diaminopropane is used as the auxiliary chain extender, using 2-7 mol% less than 8-17 mol% described in US Pat. No. 5,362,432 to minimize crystal structure weakening and heat resistance weakening. At the same time, diethyltriamine, which forms a tertiary structure in the linear polymer, is used in a manner similar to that described in Korean Patent Publication No. 98-29659, using 0.2 to 0.8 mol%, more than the technique of using ethylene diamine alone. High heat resistance could be achieved. As the amount of the auxiliary chain extender is decreased, the viscosity stability of the final polymer is lowered. To prevent this, the reaction molar ratio of the glycol diisocyanate used in the initial polymerization is adjusted to 1.4 to 1.55 to 36 to 39% of a high concentration solution. Also, the viscosity increase of the polymer solution is suppressed.

The present invention relates to a method for producing a polymer for polyurethane fibers, wherein the reaction molar ratio of poly (tetramethylene ether) glycol and methylene-bis (4-phenylisocyanate) is 1: (1.4-1.55). ) To a primary polymerization product by stirring using a homogeneous mixer at 40-50 ° C., 93 to 98 mol% ethylene diamine, 2 to 7 mol% 1,2-diaminopropane and 0.2 to 0.8 A mixture of mol% diethyltriamine is characterized as using as chain extender to polymerize it with the primary polymer.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

The poly (tetramethylene ether) glycol used to manufacture the spandex polymer for fibers of the present invention has a number average molecular weight of 1,700 to 2,000. It is preferable to use poly (tetramethylene ether) glycol whose number average molecular weight is 1,750-1,850. The poly (tetramethylene ether glycol) used reacts with an excess of organic diisocyanate compound to form an isocyanate endblocking polymer, methylene-bis (4-phenylisocyanate) is used as the organic diisocyanate, and the moles of diisocyanate per glycol The number is in the range of 1.4 to 1.55.

The production of unreacted diisocyanate in such a reaction system is inevitable, but the remaining unreacted isocyanate forms a microgel in the polymer to reduce the uniformity of the spandes physical properties. Therefore, in order to reduce the content of unreacted diisocyanate, a process of sufficiently reacting at 40 to 50 ° C. using a homogeneous mixer is necessary before the diisocyanate and glycol are reacted.

The step of forming the secondary polymer is a step in which the polymer is formed while the urea structure is formed using the blocked glycol, the chain extender, and the monoamines which are the chain stopper. As the chain extender used in the present invention, a mixture of ethylenediamine, 1,2-diaminopropane and diethyltriamine is used, which mixture is 93-98 mol% ethylenediamine, 1,2-diaminopropane 2-7. Mol% and 0.2-0.8 mol% diethyltriamine. Although diethylamine is used as a chain stopper, the addition amount of diethylamine is determined according to the molecular weight of a secondary polymer. In addition, the solvent used in this process is usually selected from inert solvents. Especially, N, N'-dimethylacetamide is mainly used because of its good solubility.

The above chain extender mixture is reacted with an isocyanate endblocking primary polymer to produce a polymer having a concentration of about 36-39%. The viscosity of the polymer was measured at 40 ° C. with a DV-III (Model No.) viscometer from Brookfield, and the viscosity measured immediately after polymerization was stirred at low speed at 30 to 40 ° C. and left to stand at initial viscosity. After that, the viscosity measured immediately before spinning is referred to as final viscosity.

The discoloration resistance improvement additive and the dyeing resistance improvement additive are added to the solution which completed superposition | polymerization, and it spins using dry spinning method. At this time, the spinning speed is suitable in the range of 450 ~ 1000m / min, high speed spinning is advantageous in terms of economics. In the present invention, spinning at a speed of 900m / min to prepare a polyurethane elastic yarn of 3f, 40den, and measured various physical properties. Spinning temperature is set to 180 ~ 280 ℃, it is adjusted so that the residual solvent amount of the elastic yarn after spinning is less than 0.5% by weight. This process gives rise to a degree of polymerization because it gives a heat treatment effect to the polymer. Intrinsic viscosity in the present invention was measured at a concentration of 0.5g per 100ml of solvent N, N'-dimethylacetamide, the intrinsic viscosity before dry spinning was 1.02 and the intrinsic viscosity after dry spinning was 1.44.

After evaluating the tensile strength, elongation and heat resistance of the prepared elastic yarn, the elastic yarn is knitted into a circular knitted fabric together with a 96 f 150den polyester yarn, refined and dyed.

<Evaluation method of physical property>

1. Tensile strength and elongation of yarn were evaluated according to KSK 0219.

2. Evaluation of the heat resistance of the yarn: The elastic yarn is stretched to twice the initial length, fixed on a 25 × 5 × 0.3 cm sus plate, and then placed in a high pressure reactor and filled after distilled water is sealed. After immersing the closed high pressure reactor in an oil circulator of 130 ° C. for 60 minutes, the high pressure reactor was taken out and left at room temperature for 10 minutes, and the sample fixed on the suspension was relaxed for 20 minutes, and then the sample length ( "Final length") was measured and the difference between the final length and the initial length was expressed as a percentage.

3. Evaluation of the degree of damage of circular knitted fabrics: Circular knitted fabrics of elastic yarns and polyester yarns which have been dyed are cut into 100 cm fabric length and 100 cm fabric width, and then 10 hours at 80 ° C. in 10% by weight aqueous sodium hydroxide solution. The yarn is then immersed to remove the polyester yarn, and then the number of trimming yarns of the elastic yarn is obtained from the remaining elastic fabric.

4. Evaluation of heat resistance of circular knitted fabric: The circular knitted fabric of elastic yarn and polyester yarn was cut into 20cm in length and 1inch in width, and the sample was stretched 5 times at 0-30% at a constant speed of 50cm / min. After the 5th elongation, the length after which the sample returned (called "final length") was measured, and the difference between the initial length and the final length was expressed as a percentage.

Embodiments of the present invention are as follows.

Example 1

556.8 kg of polytetramethylene ether glycol having an average molecular weight of 1800 and 114.6 kg of 4,4'-diphenylmethane diisocyanate were mixed in a homogeneous mixer at 45 DEG C with a terminal molar ratio of 1.48 (NCO / OH = 1.48). The reaction is carried out for 90 minutes in a pipe reactor at 95 ℃. The compound is cooled to 40 DEG C, left for about 12 hours, and then dissolved completely with N, N'-dimethylacetamide to be about 40% solids. The mixed solution was cooled to 5 ° C. for a chain extension reaction, and under a high speed stirring (200 rpm), a chain extender solution (Ethylenediamine 8.3kg / 1,2-diaminopropane 0.5kg / diethyltriamine 0.05kg) and 133.5 kg of a chain stopper solution (obtained by dissolving 1.1 kg of diethylamine in N, N'-dimethylacetamide) was added by mixing. The polyurethaneurea production solution thus synthesized contained about 37% solids and had an initial viscosity of 2620 poise at 40 ° C., and the final viscosity measured immediately before spinning was 4220 poise after being left to stir at low speed. The inherent viscosity measured at a concentration of 0.5 g per 100 ml of solvent N, N'-dimethylacetamide was 1.02.

Titanium oxide, 4.5 wt% based on the primary polymer, 1.2 wt% of para-cresol, divinyl benzene and copolymer to improve discoloration resistance and dyeability of the polymer. , Bis (4-isocyanatocyclohexyl) methane and tert-butyldiethanolamine with 3.5 wt% of polymer and antioxidant "CYANOX 1790 ^{(R )} (Product of Cynamid, USA) was added 3.5% by weight.

The polymer solution prepared as described above was allowed to stand for 40 hours, and dry spinning at a speed of 900 m / min at a spinning temperature of 250 ° C. to prepare polyurethane elastic yarns of 3f and 40den. The prepared elastic yarn was evaluated for tensile strength, elongation and heat resistance, and 96f. Knitted, refined and dyed into a circular knitted fabric with 150den of polyester yarn. The properties of yarn and circular knitted fabrics were summarized in Table 1 below.

Example 2

The terminal molar ratio of polytetramethylene ether glycol having an average molecular weight of 1800 to 4,4'-diphenylmethane diisocyanate is 1.54 (NCO / OH = 1.54), and a chain extender solution (ethylenediamine) 9.3kg / 1,2-diaminopropane 0.6kg / diethyltriamine 0.05kg) was carried out in the same manner as in Example 1 except that the composition was used differently, and the results are shown in the following [Table 1]. It was.

Comparative Example 1

In the production process of the primary polymer, the terminal molar ratio of polytetramethylene ether glycol and 4,4'-diphenylmethane diisocyanate having an average molecular weight of 1800 without using a homogeneous mixer is 1.75 (NCO / OH = 1.75), Except for using 1.6 kg (10 mol% based on ethylenediamine) of ethylenediamine 12.1 kg / 1,2-diaminopropane described in US Pat. No. 5,362,432 as a chain extender in the preparation of the secondary polymer. Was prepared in the same manner as in Example 1, and the results are shown in Table 1 below.

Comparative Example 2

In the production process of the primary polymer, the terminal molar ratio of polytetramethylene ether glycol having an average molecular weight of 1800 and 4,4'-diphenylmethane diisocyanate is 1.60 (NCO / OH = 1.60) without using a homogeneous mixer, A polymer was prepared in the same manner as in Example 1 except that 10.9 kg of ethylenediamine described in JP-A-4-100919 was used alone as a chain extender in the process of preparing the secondary polymer. Before the spinning step, diethyltriamine was added to 0.18 wt% based on the polymer to prepare a polyurethane elastic yarn, and the results are shown in Table 1 below.

Comparative Example 3

In the production process of the primary polymer, the terminal molar ratio of polytetramethylene ether glycol having an average molecular weight of 1800 and 4,4'-diphenylmethane diisocyanate is 1.62 (NCO / OH = 1.62), and the production process of the secondary polymer is Ethylenediamine 8.9 kg / 1,2-diaminopropane 2.7 kg / diethyltriamine 0.05 kg mixed liquid as described in Korean Patent Publication No. 98-29659 as a chain extender in (molar ratio = 80 / 19.7 / 0.3 A polymer was prepared in the same manner as in Example 1 except for using), and the results are shown in Table 1 below.

As can be seen through the above examples and comparative examples, the polyurethane elastic yarn obtained according to the production method of the present invention is superior to Comparative Examples 1 and 3 in terms of heat resistance of the yarn and the circular knitted fabric, and in terms of viscosity stability It is superior to Comparative Example 2. That is, the elastic yarn of the embodiment is characterized in that the heat resistance of the elastic yarn is effectively increased with little effect on other physical properties while maintaining viscosity stability.

The polyurethane elastic yarns produced according to the present invention have excellent viscosity stability and excellent heat resistance, and are very suitable as cross-linking yarns for knitting and circular knitted fabrics with polyester fibers requiring a high temperature dyeing process.

Claims (3)

The reaction molar ratio of diisocyanate to glycol was 1: 1: (1.4 to 1.55) to react with stirring to prepare an isocyanate endblock polymer, 93 to 98 mol% ethylenediamine, 2 to 7 mol% 1,2-dia A process for producing a polymer for polyurethane fibers, characterized in that a mixture of minopropane and 0.2 to 0.8 mole% diethyltriamine is used as a chain extender to react with the primary polymer. The method of claim 1, Polytetramethylene ether glycol (molecular weight 1700-2000) as glycol, and methylene-bis (4-phenylisocyanate) as diisocyanate, The manufacturing method of the polymer for polyurethane fibers characterized by the above-mentioned. Elastic fibers obtained by dry spinning the polymer for polyurethane fibers prepared according to the method of claim 1 at a temperature of 180 to 280 ℃.