JPH0227444B2 - KOSHUSHUKUSEINOAKURIRUKEIGOSEISENI - Google Patents

Description

[Detailed description of the invention]

The present invention relates to highly shrinkable acrylic synthetic fibers. Due to its good dyeability and rich texture, acrylic fibers are used as an alternative to wool for clothing, bedding, and
Widely used in the interior field. In recent years, advances in processing methods and technology have led to the creation of high-bulk yarns, artificial animal hair, etc. by blending high-shrinkage type fibers. However, due to the instability of the polymer structure of acrylic fibers, when used for a long period of time, the fibers lose their shape (stretching, sagging, denting, deformation, etc.), which significantly reduces their commercial value. This tendency is especially remarkable with shrink type acrylic fibers, and the reason for this is the manufacturing method itself of shrink cotton or high shrink cotton. Conventional methods for manufacturing high-shrinkage cotton include the method shown in Japanese Patent Publication No. 49-8818, etc., in which the amount of plastic components is increased more than usual to increase the stretchability and shrinkage rate, and the method shown in Japanese Patent Publication No. 40-1825, etc. Publication No. 1827-1972, Japanese Patent Publication No. 28897-1977, etc. describe a method in which the tow is dried after stretching under mild conditions, and if necessary, secondary stretching is performed to increase the residual shrinkage rate.
−1462 Publication, Special Publication No. 40-22008, Special Publication No.
Patent Publications No. 42-6013, Japanese Patent Publication No. 42-13747, Japanese Patent Publication No. 49-8818, etc. require sufficient heat treatment after drying.
A method has been proposed in which the residual shrinkage rate is increased by causing shrinkage and then performing secondary stretching. Due to the decrease in heat resistance of the shrink cotton obtained by the first method, the physical properties of the fiber itself (heat resistance, morphological stability, strength, crimp stability, etc.) decrease, and the fiber becomes hard and brittle especially when contracted. It also has a rough texture. Therefore, with a small amount of blended spinning, the bulkiness and improvement in texture are insufficient, and on the contrary, with a large amount of blended spinning, the texture and appearance deteriorate. The fibers obtained by the second and third methods have low physical properties (heat resistance, shape stability, crimp stability, etc.) and have problems such as dyeability and re-transmission during shrinkage. Ta. As mentioned above, high shrinkage acrylic synthetic fibers with high shrinkage rate and commercial performance such as fiber physical properties and texture have not been obtained so far. The present inventors have arrived at the present invention as a result of intensive studies. An object of the present invention is to provide a highly shrinkable acrylic synthetic fiber that has a very large shrinkage rate and also has the excellent properties inherent in acrylic synthetic fiber. The present invention comprises 50 to 95 parts by weight of an acrylonitrile polymer containing at least 88.5% by weight of acrylonitrile, and 50 to 5 parts by weight of a polyurethane which is miscible with and incompatible with the acrylonitrile polymer, and which has the following general properties. It is a highly shrinkable acrylic synthetic fiber whose S-value shown by the formula is 10.35 or more. General formula S=A/4.8+B×(1-A/100) However, A: Content of polyurethane (parts by weight) B: Content of components other than acrylonitrile in the acrylonitrile polymer (% by weight) Acrylonitrile polymer contains at least 88.5% by weight of acrylonitrile and 11.5% by weight or less of plastic components other than acrylonitrile.
If the acrylonitrile content is less than 88.5% by weight, the shrinkage rate will increase, but other required qualities of the fiber,
Performance, for example, a decrease in heat resistance, resulting in a decrease in operability and productivity in the manufacturing process, a decrease in uniformity of quality, an increase in troubles in processing after dyeing, and product quality such as hardening of texture and embrittlement of fibers, etc. This also causes major drawbacks as a product, such as deformation due to lack of morphological stability. fiber manufacturing process,
Considering the post-processing process and product performance, etc., the acrylonitrile content is preferably 89% by weight or more, more preferably 89-94% by weight, and particularly preferably 89.5% by weight.
~93% by weight. Other monomers that can be copolymerized with acrylonitrile-based polymers include hydrophobic neutral monomers such as acrylic esters, methacrylic esters, vinyl acetate, styrene, acrylamide, methacrylamide, N-methylacrylamide, NN-dimethylacrylamide, N-
Acrylic morpholine, N-acrylthiomorpholine, N-vinyl-N-methylformamide, N-
Hydrophilic monomers such as vinyl-N-methylacetamide, N-vinylpyrrolidone, N-vinylcaprolactam, N-vinylpiperidine, P-styrenesulfonic acid, methallylsulfonic acid, allylsulfonic acid, acrylic acid, methacrylic acid, vinyl Benzoic acid or salts thereof, 2-vinylpyridine, 2
Examples include ionic monomers such as -methyl-5-vinylpyridine. As the ionic monomer, sodium allylsulfonate and sodium methallylsulfonate are preferred from the viewpoint of cost, polymerizability, ease of handling, etc., and the amount may be 0.3 to 1.0% by weight. Common polyurethanes are used in the present invention, and examples of polyurethanes include polyester, polyether, polyester ether, polyester amide, and polythioether polyurethanes, specifically ethylene glycol, propylene glycol, etc. , butylene glycol, hexamethylene glycol, 1-4-
cyclohexyl glycol, P-xylene glycol, or bisphenol-A and adipic acid,
Polyesters made of suberic acid, sebacic acid, terephthalic acid, isophthalic acid or γ-lactone, polyesteramides made of adipic acid-diethanolamide or terephthalic acid-bis-propanolamide and the aforementioned dicarboxylic acids, diethylene glycol, triethylene glycol, 1.4-Phenylene-bisoxyethyl ether or 2-2'-diphenylpropane-4.4-
Polyester ethers made from bisoxyethyl ether and the aforementioned dicarboxylic acids, polyethers made from ethylene oxide, propylene oxide, and tetrahydrofuran, polythioethers such as thiodiglycol, etc. with a molecular weight of 200.
Linear polymers with ~3000 terminal hydroxyl groups are prepared using organic diisocyanates such as 1-3-phenylene diisocyanate, 1-4-phenylene diisocyanate, 2-4-tolylene diisocyanate, 4.4'-
Diphenylmethane diisocyanate, hexamethylene diisocyanate, xylene diisocyanate or 1,5-naphthylene diisocyanate and 2
It is a polyurethane polymer reacted with a chain extender of a hydrolic alcohol using a known polymerization method. The degree of polymerization of the polyurethane is preferably such that the viscosity of a dimethylformamide solution with a polymer concentration of 20% by weight at 20°C is 20 poise or more. Also, the elastic modulus of polyurethane is
The initial elastic modulus at 100% elongation is preferably 40 kg/cm ² or more. The acrylonitrile polymer and polyurethane need to be miscible in a mixed solution, but not compatible with each other. If the compatibility between the acrylonitrile polymer and polyurethane is high, the two will become a sufficiently homogeneous solution even at a large mixing ratio, and a new molecular arrangement structure will be formed, which will lead to a decrease in the heat resistance and strength of the fiber. This causes a decrease in elasticity, stiffness, and dyeability. Only by mixing miscible but incompatible materials can fibers of good quality be produced over a wide range of mixing ratios without reducing operability, productivity, etc. Being miscible means that when an acrylonitrile polymer and polyurethane are mixed (for example, when both are mixed in solution or when the other polymer is dissolved and mixed in one solution)
This indicates that one component is well dispersed and mixed in the other without gelation or aggregation. In addition, when polyurethane is mixed with an acrylonitrile polymer when there is no compatibility, the mixed solution is not homogeneous, not only by visual observation but also by microscopic observation (approximately 600 to 1000 times magnification), or when the mixed solution is dried up. This shows that when the film obtained by this method is stretched, whitening or porosity is observed. The composition of the fiber of the present invention is an acrylonitrile polymer.
50 to 95 parts by weight and 50 to 5 parts by weight of polyurethane, preferably 55 to 95 parts by weight of acrylonitrile polymer and 45 to 5 parts by weight of polyurethane, more preferably 60 to 90 parts by weight of acrylonitrile polymer and 40 to 10 parts by weight of polyurethane. Department. When the acrylonitrile polymer is more than 95 parts by weight and the polyurethane is less than 5 parts by weight, the shrinkage rate of the fibers is insufficient, the heat resistance and shape stability of the fibers are insufficient, or the appearance or appearance of the product is The texture is poor and rough. If the acrylonitrile polymer is less than 50 parts by weight and the polyurethane is more than 50 parts by weight, the phase separation between the two may become very large, or a structure in which the acrylonitrile polymer component is dispersed as island components in the polyurethane component may be formed. This should be avoided since not only does this cause a rapid decrease in fiber strength, dyeability and stiffness, but also the shrinkage reaches saturation. In order for the fiber of the present invention not only to have a sufficient shrinkage rate but also to be excellent in productivity, fiber physical properties, product performance, etc. as described above, the composition of the acrylonitrile polymer and the content of the acrylonitrile polymer and polyurethane as described above are required. The ratio must be satisfied, and the S-value shown in the above general formula must be 10.35 or more, preferably 11.35 or more. This is a standard for performance, and if the S-value is less than 10.35, sufficient shrinkage and the above-mentioned performance cannot be obtained. It is not clear why the fibers of the present invention have both sufficient shrinkage and good morphological stability, which were previously thought to be contradictory properties, but a thorough observation of the morphology and structure of the fibers of the present invention reveals that
Polyurethane exists in the acrylonitrile polymer as a phase-separated and dispersed island-like polyurethane, and the island-like polyurethane is elongated in the fiber axis direction and usually has a short axis due to the spinning of the acrylic fiber and stretching during the manufacturing process. It has an elongated form with a long axis ratio of 1:5 or more, more preferably 1:10 or more, and since this elongated polyurethane is an elastic polymer, it has a large amount of energy to contract. When fibers in this state are heated, for example when immersed in boiling water, the softening and shrinking force of the acrylonitrile polymer is combined with the shrinkage energy of the polyurethane, resulting in a fiber that far exceeds that of ordinary acrylonitrile synthetic fibers. It seems to show great contractility. The fiber of the present invention easily shrinks when heated in water, steam, or air, but the shrinkage rate in boiling water should preferably be 30% or more, and more preferably 35% or more. . Shrinkage rate
If it is less than 30%, the above-mentioned performance as high shrinkage cotton may not be fully exhibited. As mentioned above, by using an acrylonitrile-based polymer as a base material and mixing it with a predetermined amount of polyurethane, which is incompatible with it, it is possible to achieve a high degree of shrinkage, as well as good heat resistance, morphological stability, and strength. Therefore, it is possible to obtain acrylic synthetic fibers that have the following characteristics. Next, the present invention will be explained in more detail by showing an example of a method for producing the fiber of the present invention. The acrylonitrile-based polymer is produced by a normal polymerization method so that the acrylonitrile content in the polymer is 88.5% by weight, preferably 89% by weight or more, more preferably 89 to 94% by weight, particularly preferably 89.5 to 93% by weight. After polymerization and removal of residual monomers, it is dissolved in a spinning solvent to become an acrylonitrile polymer solution.
The sealability and workability of the process of polymerizing acrylonitrile polymer and preparing the polymer solution,
In terms of running time, cost, and uniformity of the polymer and polymer solution, solution polymerization, especially continuous solution polymerization using an organic solvent such as dimethylformamide, dimethylsulfoxide, or dimethylacetamide, is preferred, and among these, dimethylformamide is preferred due to its stability, ease of handling, It is most preferred in terms of ease of recovery and being a solvent for polyurethane. The polymer concentration of the acrylonitrile-based polymer is usually 15 to 35% by weight, more preferably 20 to 30% by weight in terms of viscosity, gelation, and spinnability. Polyurethane is also polymerized using the monomers mentioned above in dimethylformamide and the polymer concentration is 20~
A 40% by weight polymer solution is obtained. 50 to 95 parts by weight and 50 to 5 parts by weight, preferably 55 to 95 parts by weight and 45 to 5 parts by weight of the acrylonitrile polymer spinning stock solution and the polyurethane polymer solution, respectively,
More preferably, 60 to 90 parts by weight and 40 to 10 parts by weight are mixed to prepare a spinning dope. Any known mixing method can be used. However, if the mixing ratio is high, if the spinning stock solution after mixing is left for a long time, especially under heating, the dispersed form of polyurethane will become aggregated and large, resulting in a decrease in operability and quality, which is undesirable. After mixing, the spinning dope is spun into a coagulation bath through a conventional spinneret. In order to reduce the cost of solvent recovery and simplify the recovery process, the coagulation bath is preferably an aqueous solution of the same organic solvent as that of the spinning dope, and the organic solvent concentration is 40 to 70% by weight, preferably 50 to 65% by weight. and the temperature is 15-35℃, preferably 18-28℃
℃. The spinning dope is spun into a coagulation bath, and the coagulated filament is normally subjected to spinning and drawing through several spinning baths in which the solvent concentration is sequentially decreased. The spinning draw ratio is usually 3 times or more,
Preferably it is 4 to 6 times. After spinning and drawing, it is washed with water in a washing tank at 50°C or higher, and after pre-applying oil, it is dried and baked in a hot roller type dryer or a dryer combined with a hot air dryer. If the previous oil has a low polyurethane content,
For example, if it is less than 20 to 30 parts by weight, the amount of oil and oil adhesion that is used for ordinary flame-retardant acrylic synthetic fibers will suffice, but if the polyurethane content is high, it will tend to stick to some extent during the drying process. It is also necessary to consider factors such as an oil agent with excellent fiber splitting properties and an increase in the amount of oil adhesion. In this drying process, it is preferable to cause a slight contraction of around 10% rather than constant length tension drying in terms of drying, burning effect, and prevention of mechanical stress. For ordinary regular acrylic fibers, primary stretching is often used before drying, but in the production of high-shrinkage fibers, primary stretching after drying improves shrinkage performance, fiber luster, and dyeability. more effective in some respects. Primary stretching is done under moist heat at 60-110℃, preferably at 80-100℃
℃, and the primary stretching ratio varies depending on the amount of acrylonitrile in the acrylonitrile polymer and the content of polyurethane in the fiber, but it is suitable for shrinkage performance, strength, gloss, dyeability, fiber performance, and workability. From the viewpoint of productivity etc., it is better to carry out the stretching at a stretching ratio immediately before entering the over-stretching region. Looking at the relationship between the primary draw ratio and fiber performance, here the shrinkage rate, we find that at low draw ratios, the shrinkage rate increases as the draw ratio increases, but when the draw ratio exceeds a certain value, the shrinkage rate reaches saturation. Or, conversely, the draw ratio decreases. A stretching ratio equal to or higher than this stretching ratio is called an overstretching region. In this over-stretching region, not only saturation and decrease in shrinkage rate but also various defects occur such as decrease in fiber strength and elongation, decrease in dyeability, and single yarn breakage. Since the high-shrinkage acrylic synthetic fiber of the present invention contains 5 to 50 parts by weight of polyurethane, this overstretched region is higher than that of acrylonitrile-based synthetic fiber that does not contain polyurethane, resulting in high shrinkage. rate is easily achieved and productivity is high.
In addition, quality deterioration such as single thread breakage and fuzzing is small. After drying and crushing and before primary stretching, a step of performing large continuous shrinkage, for example 20 to 50%, may be performed and then primary stretching is performed. This continuous shrinkage treatment before the primary stretching has the effect of once again relaxing the structure of the fibers fixed by drying and burning, making them easier to stretch, and is also preferable from the point of view of improving shrinkability. It goes without saying that shrinkage processing can be performed not only continuously but also batchwise. After the primary drawing, the fibers are subjected to subsequent oil application and mechanical crimping, and are dried at a temperature of 100°C, preferably 80°C or below, so as not to cause shrinkage, to form a product. The fibers of the present invention not only have the characteristics of conventional acrylic fibers, but also have a very high shrinkage rate, sufficient fiber strength, and excellent shape stability. The fibers do not harden or become brittle, and have superior physical properties compared to conventional high shrinkage fibers. In terms of fiber production, the total stretching ratio in the production process can be made larger than that of conventional acrylonitrile polymers, resulting in a dramatic improvement in productivity. As mentioned above, the industrial significance of the fiber of the present invention is extremely large. The present invention will be explained in detail below with specific details. Parts and % in the examples indicate parts by weight and % by weight unless otherwise specified. The fiber quality was measured according to JISL-1074. Example 1 Acrylonitrile: Methyl acrylate: Sodium methallylsulfonate = X: (99.6-x): 0.4
(%) was polymerized in dimethylformamide (hereinafter referred to as DMF) by solution polymerization using azobisisobutyronitrile as an initiator. Unreacted monomers were removed from the polymerization solution, and then a water-DMF mixed solution was added so that the polymer concentration was 23% and the water content was 2% to prepare an acrylonitrile polymer solution. Next, a method for producing a polyurethane solution will be described. 100 parts of ethylene glycol, 40 parts of methylene-bis(4-phenyl isocyanate), and 2 parts of tolylene diisocyanate were reacted to obtain a urethane prepolymer having isocyanate ends. After dissolving this prepolymer in 100 parts of DMF, it was added dropwise to a solution consisting of 1500 parts of DMF, 2.5 parts of methyl-imino-bispropylamine, 9.5 parts of ethylenediamine, and 1 part of diethanolamine, and the mixture was stirred and then used in a rotary evaporator to reach a polymer concentration of 23%. A concentrated and viscous polyurethane solution was obtained. 100-X parts of acrylonitrile polymer solution,
The polyurethane solution and part X were mixed and stirred using a propeller type stirrer to obtain a spinning stock solution. The spinning stock solution was spun into a coagulation bath containing DMF:water = 57:43 (%) at 15°C from a spinneret with a pore diameter of 0.06 mm and 4000 holes. The spun yarn has a DMF concentration of 30%,
Solvent removal and 5.0 in two baths decreasing sequentially to 15%
After spinning and drawing twice as much, thoroughly washing with water in a 70°C water washing tank, and applying an oil agent in the previous oil tank, 120°C
It was dried and densified using a hot roller and a dryer with hot air at 150°C. After drying, the fibers are placed under moist heat.
It underwent continuous shrinkage of 20% at 125-130°C, and then primary stretching at 90-105°C with wet heat. The primary stretching ratio is 1.0x, 1.1x, 1.2x, 1.3x, 1.4x...
This was done by varying the magnification. After primary stretching, post-oil application, mechanical crimp, and drying with hot air at 60 to 70°C, a product was obtained. The shrinkage rate of the product was determined by cutting the fibers into 51 mm pieces, defibrating them thoroughly, placing them in a polyester net and treating them in boiling water for 30 minutes, and determining the fiber length before and after treatment. The results are shown in Table 1. The stretching ratio and shrinkage ratio in Table 1 indicate the stretching ratio immediately before entering the overstretching region and the shrinkage ratio at that time. For evaluation of polymerization, the state of gelation during DMF solution polymerization was observed, and marks such as ×, △, 〇, and ◎ were assigned in descending order of gelation tendency. The × mark indicates a tendency to gel in a short time, and the ◎ mark indicates that gelation does not occur even after a sufficiently long period of time. Operability is a judgment of the extent of troubles such as yarn breakage and sticking during the spinning process. The acrylonitrile polymer composition and polyurethane content of this sample were determined by IR spectroscopy and sulfonic acid group determination.

【table】

【table】

Claims (1)

[Scope of Claims] 1. 50 to 95 parts by weight of an acrylonitrile polymer containing at least 88.5% by weight of acrylonitrile, and 50 to 5 parts by weight of a polyurethane that is miscible with and incompatible with the acrylonitrile polymer. A highly shrinkable acrylic synthetic fiber having an S value of 10.35 or more as expressed by the following general formula. General formula S=A/4.8+B×(1-A/100) However, A: Content of polyurethane (parts by weight) B: Content of components other than acrylonitrile in the acrylonitrile polymer (% by weight) 2 Acrylonitrile weight 2. The fiber of claim 1, wherein the aggregate contains at least 89% by weight acrylonitrile. 3. The fiber according to claim 1, comprising 55 to 95 parts by weight of an acrylonitrile polymer and 45 to 5 parts by weight of polyurethane. 4. The fiber according to claim 1 or 3, comprising 60 to 90 parts by weight of an acrylonitrile polymer and 40 to 10 parts by weight of polyurethane. 5. The fiber according to any one of claims 1 to 4, which has an S-value represented by the above general formula of 11.35 or more. 6. The fiber according to claims 1 to 5, which has a hot water shrinkage rate of 30% or more.