JP4270655B2 - Copolymer elastic fiber with good low-temperature covering properties - Google Patents

Description

【００３２】
【発明の効果】
本発明によれば、低温度の下での急激な伸長回復性、特に伸長回復速度の低下が改善されており、また繊維に粘着によっておこるチーズの逆巻きに発生が少ないポリウレタンウレア系弾性繊維を得ることができる。
本発明のポリウレタンウレア弾性繊維を用いることにより、カバリング加工が寒冷期に低温下で行われても、チーズ巻体が解除に逆巻きを起すことがなく、かつまた被覆後に被覆弾性糸を弛み糸切れを起すことなく安定してチーズ上に巻取ることができる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an improved polyurethaneurea elastic fiber with excellent elongation recovery, and more particularly, release and slackening of an elastic fiber cheese roll in which yarn cutting by reverse winding is reduced even when the elastic fiber is processed at a low temperature. The present invention relates to a polyurethane urea elastic fiber capable of cheese-wrapping coated elastic yarn with reduced yarn breakage.
[0002]
[Prior art]
Elastic fibers are used for legs, pantyhose, diaper covers and the like that require stretch recovery. In these products, elastic fibers are usually used in combination with other fibers.
A composite of elastic fibers and other fibers is a single covered yarn (hereinafter abbreviated as SCY) that covers other yarns around the elastic fiber in a single layer, a double covered yarn that covers two layers of yarn, and a short fiber yarn. For example, coated core spun yarn. Then, covering or covering processing (hereinafter referred to as covering processing) of the elastic fiber is performed by covering the elastic fiber in a stretched state, and then the covering yarn or the covering yarn as a processing yarn is wound around the cheese after being contracted by a certain ratio. . These covering processes are performed continuously, and in particular, there is a constant demand for elastic fibers that are particularly excellent in stretch recovery in a short time.
[0003]
Japanese Patent Application Laid-Open No. 7-289883 uses a low molecular weight polytetramethylene ether glycol (hereinafter abbreviated as PTMG) or PTMG from which a high molecular weight portion has been removed for the purpose of obtaining an elastic fiber excellent in stretch recovery. A method for producing elastic fibers is described. JP-A-1-284518 discloses a technique for imparting stretch recovery to an elastic fiber by copolymerizing neopentyl glycol and imparting a methyl group to a side chain upon ring-opening polymerization of tetrahydrofuran (hereinafter abbreviated as THF). Is disclosed.
[0004]
As the use of elastic fibers increases, the problem of thread breakage in the covering process of elastic fibers has been highlighted. In particular, when the covering process is performed in the morning of the cold season, there are frequent occurrences of thread breakage of the elastic fiber due to the reverse winding of the elastic fiber cheese that occurs during the start of the process, and the covering thread due to the slack of the covering thread in the cheese winding process of the covering thread The problem of frequent cuts is serious.
[0005]
Here, as well known, “reverse winding” is a phenomenon in which when the elastic fiber is released from the cheese, the yarn is separated from the surface of the cheese and the yarn is wound in the reverse direction. On the other hand, thread breakage due to loosening is caused by a decrease in the stretch recovery property of elastic fibers within a short time in the start-up period of processing under the cold season.
Observing the temperature dependence of the elongation recovery rate of a general-purpose polyurethane elastic yarn, as exemplified below, the elastic recovery rate observed during a period of 10 seconds or less even at room temperature of 0 to 20 ° C. is elastic. It was found that the temperature of the fiber dropped dramatically as it shifted to the lower temperature side.
[0006]
For example, an elastic fiber of 20d is sampled with an initial length of 100 mm, and is stretched to 200 mm and left at a predetermined temperature for 16 hours, then the tension is released and the length (L) after 10 seconds is measured (L-100 ) When compared with the value of (mm) (hereinafter referred to as elongation recovery property: the smaller the numerical value, the higher the recovery rate characteristic), PTMG having a number average molecular weight of 1900 having a low temperature elongation recovery rate of 10 mm at 20 ° C. Polyurethane urea elastic fiber having a 4-4 ′ diphenylmethane diisocyanate as a soft segment, ethylenediamine as a chain extender, and dry-spun, has a high molecular weight PTMG content, 53.4 mm at 10 ° C. and 81 mm at 0 ° C. As the temperature decreases, the elastic recovery of elasticity decreases rapidly.
[0007]
Thus, the problem is inferred from the knowledge that the stretch recovery property of the elastic fiber rapidly decreases as the temperature decreases.
Elastic fiber cheese has fallen by night temperature at the time of cold, and the elongation recovery property of elastic fiber has fallen significantly. In addition, the elastic fiber cheese is heated at the start of covering, but the elastic yarn on the cheese surface is warmed, but the inside is still cold, and this part becomes low shrinkage in the cheese winding process of the covering yarn, causing slack in an instant, The hook is caught by an adjacent protrusion, the slack portion is tangled and caught by the guide, or the slack portion is taken into the roller at a time and the covering yarn is cut.
[0008]
[Problems to be solved by the invention]
Even if the covering process of the elastic fiber is performed under a low temperature encountered in the cold season, the cheese roll does not cause reverse winding to release, and does not cause loose yarn breakage after coating and is stable on the rolled-up cheese. It is an object of the present invention to provide a polyurethaneurea elastic fiber that can be taken off.
[0009]
A specific problem of the present invention is to provide a polyurethane urea-based elastic fiber that improves a rapid elongation recovery property, particularly a decrease in the elongation recovery rate accompanying a temperature decrease of the elastic fiber, and has less reverse winding with cheese accompanying adhesion. There is.
[0010]
[Means for Solving the Problems]
The present invention can be achieved particularly by using an alkylene diol having a methyl side chain as a soft segment forming component and controlling the upper limit allowable amount of the cyclic oligomer present in the polyurethane urea forming the fiber very precisely. .
[0011]
That is, the present invention provides a low-temperature composition comprising a polyurethaneurea having a content of a cyclic oligomer having 9 or less repeating units and 1.5% by weight or less and a copolymer polyalkylene ether diol having a methyl group side chain as a diol component. Polyurethane urea elastic fiber with excellent covering properties.
The polyurethane urea constituting the elastic fiber of the present invention is composed of a soft segment having a urethane bond between a polyalkylene ether diol having a methyl group side chain and an organic diisocyanate, and a urea bond between an isocyanate at both ends of the soft segment and a bifunctional organic diamine. It consists of a hard segment.
[0012]
This hard segment forms a hydrogen bond with each other, forms a molecular interbonding point, and a cross-linking point called rubber, and expresses elastic performance in the fiber.
In the present invention, an alkylene diol having a methyl side chain is used as a soft segment forming component of the polymer. Employing alkylene diols having methyl group side chains can inhibit the growth of crystals in the polymer, increase the elongation of the resulting elastic fiber, and maintain significantly the stretch recovery at low temperatures. it can. On the other hand, in the copolymerization of a polyalkylene ether diol having a methyl group side chain, the formation of cyclic oligomers tends to increase, and the bleed of the cyclic oligomers to the elastic fiber surface increases the adhesiveness of the elastic fiber surface. When the amount of the bleed becomes a certain value or more, the adhesiveness between the elastic fibers suddenly increases, and yarn breakage due to reverse winding with cheese caused by adhesion tends to occur.
[0013]
In order to obtain elastic fibers with good covering properties at low temperatures during cold weather, the methyl group side chain of the diol used is more than the amount of copolymerization that forms crystals when stretched at low temperatures, and the elastic fibers are adhesive. It is important to reduce the content of the cyclic oligomer that increases the property, but it is particularly important to make it 1.5% by weight or less.
As the alkylene group used for copolymerization, one of the alkylene groups is a tetramethylene group from the viewpoint of the water resistance, light resistance, abrasion resistance, and elastic function of the obtained polyurethane elastic fiber, and is co-polymerized with other alkylene groups. Polymerization is preferred. As the alkylene group to be copolymerized, a 2,2-dimethylpropylene group, a 3-methylpentamethylene group and a 3-methyltetramethylene group are preferable. Particularly preferred is a 2,2-dimethylpropylene group.
[0014]
Moreover, it is preferable to contain 4 mol% or more and 40 mol% or less of alkylene ether units other than a tetramethylene group. Preferably they are 8 mol% or more and 30 mol% or less. If it is less than 4 mol%, the tetramethylene group tends to form crystals during low-temperature elongation, resulting in a decrease in elongation recovery and sagging of the covering yarn, and if it exceeds 40 mol%, the strength or elongation of the elastic fiber tends to decrease. is there.
[0015]
The copolymer polyalkylene ether diol has an oligomer content of 9 or less repeating units of 1.5% by weight or less, particularly preferably 1.0% by weight or less. When the oligomer content is 1.5% by weight or less, the adhesiveness of the elastic fiber surface is drastically lowered, and the reverse winding is remarkably improved. Moreover, even if the alkylene ether unit other than the tetramethylene group is a mixed polyalkylene ether diol present in the above-mentioned mol% range, it is used if the content of the cyclic oligomer is 1.5% by weight or less. May be.
[0016]
As for the number average molecular weight (Mn) of the copolymerization polyalkylene ether diol used by this invention, 1000-40000 are preferable. When Mn is less than 1000, the amount of cyclic oligomer having 9 or less repeating units is increased, and when it is more than 4000, hysteresis loss and elongation recovery at low temperature are deteriorated.
The elastic fiber of the present invention comprises a copolymerized polyalkylene ether diol having a methyl group side chain in which the content of a cyclic oligomer having a number average molecular weight of 1000 to 40000 and a repeating unit of 9 or less does not exceed 1.5% by weight. A component is reacted with an excess of an organic diisocyanate, for example, 4,4′-diphenylmethane diisocyanate, to synthesize an isocyanate prepolymer at both ends by a conventional method. The molar ratio of diol to diisocyanate is 1.2 to 1.8, and the molecular weight of the soft segment can be adjusted to a range of 4000 to 8000. The cyclic oligomer does not react with the diisocyanate and is directly incorporated into the prepolymer. Next, a polyurethane urea is obtained by reacting both terminal isocyanate prepolymers with a bifunctional organic diamine in the presence of an appropriate amount of a monofunctional organic amine. The prepolymer and diamine can be dissolved in a solvent and mixed to form a polyurethane urea spinning stock solution, and a polyurethane urea elastic fiber can be obtained by applying general-purpose dry or wet spinning.
[0017]
In the preparation of the above-described polyurethane urea polymer, the copolymerized polyalkylene ether diol having a methyl group side chain to be used may be produced by any method. A heteropolyacid disclosed in JP-A-58-95036 is used as a catalyst, and THF and neopentyl glycol, 3-methyl-1,5-pentanediol, or a dehydrated cyclic compound thereof such as 3,3-dimethyloxetane It is manufactured by reacting. The copolymerized diol is obtained by changing the reaction method and conditions variously so as to obtain a predetermined molecular weight and copolymerization ratio, thereby obtaining a diol having a cyclic oligomer content of 9 units or less of repeating units of 1.5% by weight or less. be able to.
[0018]
The reduction in the content of cyclic oligomers of 9 or less repeating units can be adjusted by the pressure, temperature and time in the thin film decompression treatment. The cyclic oligomer content can also be reduced by octane washing.
The organic diisocyanate compound used for the synthesis of the polyurethane urea polymer of the present invention is 4,4′-diphenylmethane diisocyanate, 2,4-toluene diisocyanate, 1,4-phenylene diisocyanate, 4,4′-cyclohexylmethane diisocyanate. -G and the like.
[0019]
Examples of the bifunctional organic diamine include hydrazine, ethylenediamine, 1,2-propylenediamine, 1,4-butyldiamine, 1,6-hexamethylenediamine, 1,3-cyclohexyldiamine, 4,4′diaminodiphenylmethane, 4,4. And '-diaminodicyclohexylmethane. Among these diamines, ethylenediamine, 1,2-propylenediamine, 1,6-hexamethylenediamine, or a mixture thereof is preferable as a material that gives good physical properties.
[0020]
As the monofunctional organic amine used in the present invention, diethylamine, dimethylamine, dibutylamine, diethanolamine and the like can be used.
Examples of the inert polar solvent used for the synthesis of the polyurethane urea polymer include dimethylformamide, dimethylacetamide, dimethylsulfoxide and the like.
[0021]
Antioxidants, ultraviolet absorbers, yellowing inhibitors and the like are added to the spinning dope prepared as described above. After the foreign material is removed with a filter, the spinning dope mixed with various additives is fed a certain amount and pushed through a nozzle in heated air or an air current such as an inert gas. The spinning solution is extruded and formed, and the filament (fiber) is evaporated by the hot air current under the spinneret to form a filament, which is then converged by applying false twist, and then given an oil agent and given. An elastic fiber having the following characteristics can be obtained.
[0022]
【Example】
Hereinafter, the present invention will be described more specifically based on examples and the like, but the present invention is not limited by these examples and the like. In addition, the measured value in the following Examples is obtained by the measuring method described below.
(1) Measurement of polydispersity d which is a weight average molecular weight, a number average molecular weight, and a ratio thereof:
The measurement was performed by gel permeation chromatography (GPC) under the following conditions. The PTMG solid was dissolved in 3 mL of THF, and 1 mL of the solution was injected into GPC and measured. The GPC measurement conditions and the outline of the apparatus are as follows. The solvent was THF, the solvent flow rate was 1 mL / min, and the column temperature was 40 ° C. The system is SCL-6B (manufactured by Shimadzu) as a system controller, CTO-6A (manufactured by Shimadzu) as a column oven, the detector is a differential refractometer RID-6A (manufactured by Shimadzu), and the column is TSK-gel G3000HXL x 2 (manufactured by Tosoh) Was measured and data processing was performed to calculate the average molecular weight and polydispersity.
(2) Evaluation of thread trimming during covering of elastic fiber:
The elastic fiber cheese is stored in a polyethylene bag for 25 months at 25 ° C. and then covered. Covering processing is Ozeki Techno Co., Ltd.'s covering machine ON-741S, elastic fiber cheese, polyamide fiber (made by Asahi Kasei Kogyo Co., Ltd.) Reona 10d / 5f) cheese is attached and kept at 10 ° C. for 16 hours. Thereafter, the outside air temperature is increased to 15 ° C., and covering of the elastic fiber is started after 5 minutes. The covering conditions are a draft rate of 2.7, a twist number of 1600 T / m, a single cover S twist, and a Z twist. The winding ratio of the covered SCY was 0.95 times the covering roll speed. A total of 10 spindles are covered with cheese and run for 10 minutes after the start of covering, the yarn breaks due to reverse winding or slack, etc., and the number of spindles where the processing machine stops is counted. Judge that it is appropriate.
(3) Measurement of cyclic oligomer:
Copolymerized PTMG was diluted with twice the amount of chloroform and gas chromatography {column: silicon SE-30 10 wt% / chromosolve WHP × 1 m (glass) column temperature 295 ° C.} was performed.
(4) Measurement of composition ratio
1 H. It was determined by 13 C-NMR (JEOL-GX 400 manufactured by JEOL Ltd.).
[Example 1]
(Manufacture of polyurethane urea elastic fiber)
In a container equipped with a stirrer and a reflux condenser, 500 g of THF and 56 g of neopentyl glycol are charged. Add 500 g of adjoining tungstic acid heated at 340 ° C. for 3 hours and keep it at 60 ° C. in a dry nitrogen gas atmosphere for 10 hours to stir and react, then leave at room temperature to separate into two phases . The upper layer was separated, and unreacted THF and neopentyl glycol were removed by distillation to obtain 140 g of a transparent and viscous polyalkylene ether diol. As a result of the analysis, the number average molecular weight was 2000, the ratio of the side chain-containing units was 15%, and the content of the cyclic oligomer having 9 or less repeating units was 4%.
[0023]
100 g of pure water was added to 100 g of the polyalkylene ether diol, and the mixture was stirred at 30 ° C. for 20 minutes. Thereafter, the mixture was allowed to stand at room temperature for 18 hours, and the copolymerized PTMG was separated into the upper layer and the aqueous layer was separated into the lower layer to remove the catalyst. The polyalkylene ether diol in the upper layer liquid was removed under reduced pressure heating of the thin film, and the number average molecular weight, the ratio of the side chain containing units, and the cyclic oligomer content of 9 or less repeating units were measured, and the results shown in Table 1 were obtained. .
[0024]
2,000 g of the copolymerized polyalkylene ether diol and 400 g (1.6 mol) of 4,4-diphenylmethane diisocyanate (hereinafter abbreviated as MDI) were allowed to react under stirring at 80 ° C. for 3 hours under dry nitrogen. A polymer was obtained. After cooling this to room temperature, 457 g of dimethylacetamide was added and dissolved with stirring at room temperature to obtain a uniform prepolymer solution.
[0025]
On the other hand, a solution prepared by dissolving 34.2 g (0.57 mol) of ethylenediamine and 4.38 g (0.06 mol) of diethylamine in 1,233 g of dimethylacetamide was added to the prepolymer solution at high speed with rapid stirring, and further at room temperature. It was made to react for 1 hour and the polyurethane urea was obtained. To this solution, a predetermined amount of additives such as an antioxidant and an anti-yellowing agent was added and mixed to obtain a dry spinning dope. The solid content concentration of the entire spinning dope was about 35%. This spinning stock solution was supplied to a dry spinning machine, and 450 g of 20 denier 2-filament elastic fiber was wound on a paper tube having a diameter of 85 mm and a width of 50 mm at a winding speed of 800 m / min.
(Covering process)
The elastic fiber cheese was left in a polyethylene bag at 25 ° C. for 1 month, and then covered. The number of covering machines stopped was 0%. The thread breakage evaluation test at the time of covering was repeated 10 times, but no thread breakage occurred within 10 minutes after starting. In this example, it was considered that 15% of methyl group side chains were present, crystallization during low-temperature elongation was small, and elongation recovery at low temperatures was not inhibited. The content of the cyclic oligomer is also low at 0.8% by weight with the raw material diol, there is little bleeding on the surface of the elastic fiber, the tackiness is weak, and it seems that no reverse winding occurs.
[Example 2]
(Manufacture of polyurethane urea elastic fiber)
The copolymerized polyalkylene ether diol was polymerized in the same manner as in Example 1, the oligomer was removed under reduced pressure heating, and the number average molecular weight, the ratio of the side chain-containing units, and the cyclic oligomer content of 9 or less repeating units were measured. The results shown in Table 1 were obtained.
[0026]
In the same manner as in Example 1, polymerization and spinning were performed to obtain an elastic fiber, which was left for one month and then covered. The number of covering machines stopped was 0%. The thread breakage evaluation test at the time of covering was repeated 10 times, but no thread breakage occurred within 10 minutes after starting.
[Comparative Example 1]
(Manufacture of polyurethane urea elastic fiber)
The copolymerized polyalkylene ether diol was polymerized in the same manner as in Example 1, the oligomer was removed under reduced pressure heating, and the number average molecular weight, the ratio of the side chain-containing units, and the cyclic oligomer content of 9 or less repeating units were measured. The results shown in Table 1 were obtained.
[0027]
In the same manner as in Example 1, polymerization and spinning were performed to obtain an elastic fiber, which was left for one month and then covered. The number of covering machines stopped was 30%. The thread breakage evaluation test during covering processing was repeated 10 times, and the thread breakage occurred within 10 minutes out of 10 times.
In this comparative example, it has 16% of methyl group side chains, the crystallization at low temperature elongation is small, and it seems that the elongation recovery at low temperature was not inhibited. On the other hand, the content of the cyclic oligomer is as high as 3.8% by weight of the raw material diol, and the adhesiveness of the elastic fiber surface is increased.
[Example 3]
(Manufacture of polyurethane urea elastic fiber)
In a vessel equipped with a stirrer and a reflux condenser, 500 g of THF and 1.6 g of water are charged. Add 50 g of adjoining tungstic acid heated at 340 ° C. for 3 hours to an anhydrous state, hold at 60 ° C. in a dry nitrogen gas atmosphere, and stir 3,3-diethyloxetane 90 g at a rate of 0.75 g / min. Then, the mixture is reacted for 6 hours while stirring at 60 ° C. When allowed to stand at room temperature, it separated into two phases, and the supernatant or unreacted THF and 3,3-dimethyloxetane were removed to obtain 153 g of transparent and viscous polyolene ether diol.
[0028]
100 g of pure water was added to 100 g of the polyalkylene ether diol, and the mixture was stirred at 30 ° C. for 20 minutes. Thereafter, the mixture was allowed to stand at room temperature for 18 hours, and the copolymerized PTMG was separated into the upper layer and the aqueous layer was separated into the lower layer to remove the catalyst. The polyalkylene ether diol in the upper layer liquid was removed under reduced pressure heating of the thin film, and the number average molecular weight, the ratio of the side chain-containing units, and the cyclic oligomer content of 9 or less repeating units were measured, and the results shown in Table 1 were obtained. .
[0029]
The copolymerized polyalkylene ether diol was reacted with MDI in the same manner as in Example 1 to prepare a prepolymer, and a solution of ethylenediamine and diethylamine dissolved in dimethylacetamide was added to the prepolymer solution at high speed with stirring at room temperature, and further at room temperature for 1 hour. Reaction was performed to obtain polyurethaneurea. To this solution, a predetermined amount of additives such as an antioxidant and an anti-yellowing agent was added and mixed to obtain a dry spinning dope. The solid content concentration of the entire spinning dope was about 35%. This spinning stock solution was supplied to a dry spinning machine, and 450 g of 20 denier 2-filament elastic fiber was wound on a paper tube having a diameter of 85 mm and a width of 50 mm at a winding speed of 800 m / min.
[0030]
The test for evaluating the yarn breakage during the covering process was repeated 10 times, and the yarn breakage within 10 minutes out of 10 was good, 0 times.
[0031]
[Table 1]

[0032]
【The invention's effect】
According to the present invention, a rapid extension recovery property under a low temperature, in particular, a reduction in the extension recovery rate is improved, and a polyurethane urea-based elastic fiber that is less likely to occur in reverse winding of cheese caused by sticking to the fiber is obtained. be able to.
By using the polyurethane urea elastic fiber of the present invention, even if the covering process is performed at a low temperature in the cold season, the cheese roll does not cause reverse winding to release, and the coated elastic yarn is loosened after coating and the yarn is broken. It can be stably wound on cheese without causing any problems.

Claims (3)

A polyurethane urea-based elastic fiber having a low-temperature covering property having a cyclic oligomer content of 9 or less repeating units and 1.5% or less and a copolymer polyalkylene ether diol having a methyl group side chain as a diol component. 2. The polyurethane urea-based elastic fiber according to claim 1, wherein the copolymerized polyalkylene ether diol having a methyl group side chain has a number average molecular weight of 1000 or more and 40000 or less. The copolymer polyalkylene ether diol having a methyl side chain is copolymerized with a tetramethylene group and any of 2,2-dimethylpropylene group, 3-methylpentamethylene group and 3-methyltetramethylene group. The polyurethane urea elastic fiber according to claim 1 or 2, characterized in that