JPH0227441B2 - DODENSEIAKURIRUKEIGOSEISENINOSEIZOHOHO - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing conductive acrylic synthetic fibers. In general, synthetic fibers have poor antistatic properties, and especially in low-humidity environments during winter, static electricity is generated significantly in clothing, clothing, etc.
Improvements have been desired not only in interior design, bedding, etc., but also in industrial applications, and various proposals have been made.
One way to overcome these drawbacks is to use metal fibers, metal-plated fibers, or carbon fibers, and by mixing them with other fibers, the antistatic properties are improved, but these fibers are generally Because its physical properties, luster, color, and dyeability are different from ordinary synthetic fibers and natural fibers, special blending, spinning, dyeing, and processing methods are required, and its use is limited to carpets, etc. is normal. In order to improve the above-mentioned drawbacks of conductive fibers, a method has been proposed in which a conductive substance such as carbon black is mixed into part or all of the synthetic fibers. The method of mixing a conductive substance into the entire fiber has many drawbacks such as a large amount of conductive substance used, high cost, reduced operability, productivity, reduced spinnability, weaving and knitting properties, and abnormal dyeability. are doing. Methods for mixing a conductive substance into a portion of the fibers can be broadly classified into composite spinning, sea-island fiber spinning, and conductive layer streak dispersion spinning. Japanese Patent Publication No. 52-31450 or Japanese Patent Application Publication No. 51-
In Publication No. 143723, etc., sheath-core type or side-by-side type conductive composite fibers have been proposed, but they are difficult to manufacture, have low productivity, and suffer from decreased conductivity due to fibrillation and peeling of each component, and poor dyeability. This may cause changes and deterioration of appearance. JP-A-56-3447, JP-A-56-68109, JP-A-56-58008
Although publications such as the above publication attempt to improve the above-mentioned drawbacks of composite fibers by using more complicated manufacturing methods, the manufacturing difficulties and low productivity are still significant, and only a small improvement in performance and quality can be expected. I think that the. Special Publication No. 53-31971, Publication No. 57-20404,
In JP-A-54-112212, JP-A-55-45856, and JP-A-52-103525, conductive substances such as carbon black, silver, copper, aluminum, and iron are continuously applied in the fiber axis direction. A method of orienting and dispersing the conductive material has been proposed, but in order to continuously orient and disperse the fiber in the axial direction, block polyether or a copolymer of block polyether grafted with a vinyl monomer such as AN is used as the conductive material. It must be used as a dispersion matrix polymer for conductive fibers, which is not only industrially difficult but also has low heat resistance and low strength and elongation, which affect the physical properties of conductive fibers.
degrade performance. In addition, conductivity tends to decrease due to stretching during the manufacturing process and processing stage, and external forces such as stretching and bending after the product is manufactured. This is considered to be because in wet spinning, the conductive component and the non-conductive component are largely separated due to their incompatibility. The present inventors have arrived at the present invention as a result of intensive studies to eliminate the above-mentioned drawbacks. The purpose of the present invention is to provide a conductive acrylic synthetic fiber having excellent conductivity, excellent workability, and high product performance, and another purpose of the present invention is to manufacture such a fiber inexpensively and easily. We are here to provide you with a method. The present invention relates to an acrylic polymer solution and conductive fine particles.
A solution of a conductive elastic polymer consisting of 10 to 70% by weight and 90 to 30% by weight of an elastic polymer that is miscible with the acrylic polymer but incompatible with the acrylic polymer/
Conductive elastic polymer = 50/50 to 90/10 (weight ratio) mixed, dry spun at a spinning draft of 20 times or less, hot water stretched to 3 times or less, washed with water, dried, and then shrunk under moist heat. It is characterized by causing Acrylic polymer solution and conductive elastic polymer solution are acrylic polymer/conductive elastic polymer = 50/50
~90/10 (weight ratio), preferably 55/45 to 85/15
(weight ratio), more preferably 60/40 to 80/20 (weight ratio). Acrylic polymer is 90
If the amount of the conductive elastic polymer exceeds 10 parts, the conductivity will not be sufficiently developed because the conductive component will be small and the elongation in the fiber axis direction will be insufficient. Also, if the acrylic polymer is less than 50 parts and the conductive elastic polymer exceeds 50 parts, the dispersion form of the conductive elastic polymer component in the fiber will become abnormally large, and the shape distribution will also widen, causing problems during the manufacturing process. Problems occur frequently during thread breakage and during spinning, weaving and knitting processes, and the dyeability of the fibers decreases in gloss. Acrylic polymers applicable to the present invention include acrylonitrile polymers containing 80% by weight or more of acrylonitrile, and halogen-containing monomers containing less than 80% by weight of acrylonitrile and vinyl chloride, vinylidene chloride, vinyl bromide, vinylidene bromide, etc. Examples include flame-retardant acrylic polymers containing 20 to 60% by weight of at least one type. Examples of monomers copolymerizable with acrylic polymers include acrylic esters or alkyl methacrylates such as methyl acrylate, methyl methacrylate, and ethyl acrylate, amides such as acrylamide and methacrylamide, and their N- Also included are monosubstituted or NN-disubstituted amides, vinyl acetate, monomers containing sulfonic acid groups such as styrene sulfonic acid, and salts thereof. In particular, 0.3 to 5.0% by weight of allylsulfonic acid or methallylsulfonic acid and salts thereof, preferably
Copolymerization of 0.5 to 3.0% by weight not only improves the dyeability but also suppresses the deterioration of heat resistance by suppressing the generation of countless minute voids. Further, the elastic polymer applied to the present invention needs to be miscible with the acrylic polymer but not compatible with the acrylic polymer. Examples of such elastic polymers include polyurethane polymers, acrylonitrile-butadiene rubber, acrylic rubber, etc., and polyurethane polymers are preferred in terms of physical properties such as solvent solubility, fiber forming properties, and rubber elasticity. Polyurethane polymers include polyester type, polyether type, polyester ether type,
A general term for polyesteramide type and polythioether type polyurethanes, specifically ethylene glycol, propylene glycol, butylene glycol, hexamethylene glycol, 1,4-cyclohexyl glycol, P-xylene glycol, or bisphenol A and adipic acid, suberin. polyester consisting of acid, sebacic acid, terephthalic acid, isophthalic acid or γ-lactone, etc.
Polyesteramide made from 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. Molecular weight
A flocculent polymer having 200 to 3000 terminal hydroxyl groups is mixed with an organic diisocyanate such as 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, 2,4-tolylene diisocyanate,
It is a polyurethane polymer obtained by reacting 4,4'-diphenylmethane diisocyanate, hexamethylene diisocyanate, xylene diisocyanate, or 1,5-naphthylene diisocyanate with a dihydric alcohol chain extender using a known polymerization method. It is necessary that the acrylic polymer and the elastic polymer have miscibility but are incompatible. Having miscibility means that when mixing an acrylic polymer and an elastic polymer (for example, mixing both solutions or dissolving and mixing the other polymer in one solution), one component does not gel or aggregate, and one component does not mix with the other. Indicates that it is well dispersed and mixed in the ingredients. In addition, when an acrylic polymer is mixed with an elastic polymer, the lack of compatibility can be determined not only by visual observation but also by microscopic observation (approximately 600 to 1000 times magnification) because the mixed solution is heterogeneous. The conductive elastomeric polymer contains 10 to 70% by weight of conductive particles and 90 to 90% of the aforementioned elastomeric polymer that is miscible but incompatible with the acrylic polymer.
It consists of 30% by weight. When the amount of conductive particles is less than 10% by weight, conductivity is not sufficiently imparted, and when it exceeds 70% by weight, not only operability and processability are significantly reduced, but also the conductivity reaches saturation, which is extremely inconvenient. The conductive particles applicable to the present invention include particles of carbon black, metals such as silver, copper, aluminum, and iron, tin oxide, zinc oxide, and titanium oxide coated with tin oxide or zinc oxide. The particle size of these particles is usually 1 μm or less, preferably 0.7 μm or less, particularly preferably 0.5 μm or less.
A material with a diameter of about 0.01 μm is used. Carbon black as a conductive particle has a particle size of
It is preferably 1 μm or less, and its type is not particularly limited, and examples thereof include so-called acetylene black, oil furnace black, channel black, and the like. Metal particles such as silver, copper, aluminum, iron, etc. are usually those having a particle size of 1 μm or less, preferably 0.5 μm or less, and having a resistivity of 10 Ω·cm or less. Regarding the electrical conductivity of conductive zinc oxide or tin oxide, the specific resistance in powder form is preferably about 10 ⁴ Ω·cm or less, particularly preferably about 10 ² Ω·cm or less, and most preferably about 10 ¹ Ω·cm or less. In reality, values of about 10 ² Ω·cm to ^{10 −2} Ω·cm have been obtained, and can be suitably applied to the purpose of the present invention. Titanium oxide having a coating of zinc oxide or tin oxide has a particle size and specific resistance in powder form comparable to those of zinc oxide or tin oxide. These films can be formed, for example, by a vacuum deposition method, a method of depositing a metal compound and baking it to form an oxide, or a method of partially reducing it. When carbon black is used as conductive particles, it has the disadvantage that the color of the fiber becomes black, but because of its small specific gravity and cluster (microscopic chain) structure, carbon black can be used in small quantities. The content in the conductive elastic polymer is preferably 10 to 50% by weight, more preferably
It is 15-40% by weight. Since conductive particles other than carbon black have a large specific gravity, the amount used is also larger than in the case of carbon black, which causes an increase in cost, but there is a great advantage that the fiber color is not black. In particular, white conductive fibers can be obtained using conductive tin oxide, zinc oxide, and titanium oxide with surface coatings thereof. As the solvent for the acrylic polymer, dimethylformamide, dimethylsulfoxide, dimethylacetamide, ethylene carbonate, γ-butyrolactone, and other organic solvents can be used. As the solvent for the elastic polymer, a solvent for the elastic polymer can be used. The same solvent as used for the acrylic polymer is preferred from the viewpoint of solvent recovery. Particularly preferably, the acrylic polymer and polyurethane are each subjected to solution polymerization using dimethylformamide as a common solvent. When dimethylformamide is used as a solvent, the polymer concentration of the acrylic polymer solution is 20 to 50% by weight, preferably 25 to 35% by weight, and the polymer concentration of the polyurethane solution is also lower than that of the acrylic polymer, or almost The same level is fine. The acrylic polymer solution and the elastomeric polymer solution must be mutually miscible but incompatible, and it is also necessary that the conductive fine particles remain in the elastomeric polymer solution. The viscosity of the acrylic polymer solution and the elastomeric polymer solution also has a significant impact on operability, product quality, and conductive performance. The viscosity here refers to the viscosity at the same polymer concentration and at the same temperature. The viscosity at 50° C. of a dimethylformamide solution with a polymer concentration of 20% by weight is usually used. For example, if the viscosity of the acrylic polymer solution is slightly lower than the viscosity of the elastomeric polymer solution, the elastomeric polymer will not be sufficiently deformed during fiber spinning.
This results in uneven denier in that part, yarn breakage, and insufficient conductivity. On the other hand, if the viscosity of the acrylic polymer solution is equal to or greater than the viscosity of the elastomeric polymer solution, the elastomeric polymer will be sufficiently stretched during spinning and will be formed into island-like components elongated in the fiber axis direction. For that reason,
No phenomena such as denier unevenness or deterioration of operability were observed, and the conductivity was also good. The viscosity ratio of the acrylic polymer solution and the elastic polymer solution is preferably 100/1 or less, more preferably 1/4 to 50/1. Conductive elastic polymer contains 10 to 70% by weight of conductive fine particles
and 90 to 30% by weight of an elastic polymer. When carbon black is used as the conductive particles, the carbon black is preferably 10 to 50% by weight, more preferably 15 to 40% by weight, and the elastic polymer is preferably 10 to 50% by weight.
The content is 90 to 50% by weight, more preferably 85 to 60% by weight. Various methods can be used to mix the conductive fine particles into the elastic polymer. For example, there are methods such as adding it when polymerizing the elastic polymer or adding it to the elastic polymer solution, but care must be taken to apply sufficient stirring force to disperse the conductive fine particles and in the case of carbon black. Stirring is performed in a manner that does not break the carbon black clusters, and after adding conductive fine particles, this conductive elastic polymer solution or a spinning stock solution of a mixture of an acrylic polymer solution and a conductive elastic polymer solution is mixed with paper. It is preferable to use a cloth, a sintered metal filter, a wire mesh, or a porous polymer membrane. The overaccuracy here is about 10μ to 50μ
It is sufficient to remove 100% of the particles. Various dispersants can also be used to improve the dispersibility and stability of the conductive particles in the elastomeric polymer. Various mixing methods can be used to mix the acrylic polymer solution and the conductive elastic polymer solution.
It is better to check the mixing state using a microscope or the like. The conductive elastic polymer solution, which appears black under a microscope, is suspended and dispersed in the acrylic polymer solution as many small spheres or deformed spheres, but the size of this dispersion is uniform and 10 ~
The thickness is preferably about 150μ, more preferably about 30 to 100μ. The spinning dope obtained by mixing the two is spun using a conventional spinneret for dry spinning. Since the spinning dope has a high polymer concentration, it is necessary to heat it to a suitable viscosity, and it is preferable to heat it to approximately 50 to 100 poise. However, since the spinning dope tends to be colored when heated, the heating should be done for as short a time as possible. The fibers are spun into heated air or an inert gas such as nitrogen or helium, and the solvent is removed by evaporation in the spinning tube. The heating temperature is preferably 150°C or higher. The amount of gas must be flowed so as to be outside the explosive range of the solution contained, and is usually below the lower explosive limit. It is preferable that the direction of gas flow be the same as the direction of the fibers in order to prevent problems such as yarn wobbling, uneven denier, and sticking. The spinning draft is 20 times or less, preferably 3-15
It is carried out twice, more preferably 5 to 12 times. When the spinning draft exceeds 20 times, yarn breakage occurs frequently during the spinning stage. The spun fibers are stretched in hot water or in an aqueous solvent solution by a factor of 3 times or less, preferably 1.1 to 2 times. If the stretching ratio exceeds 3 times, the continuity of the conductive layer in the fiber is likely to be broken, resulting in a decrease in conductivity. After stretching, it is preferably washed with warm water or hot water, and after applying an oil agent, it is dried and crushed. It is necessary to dry and crush thoroughly, preferably 100 to 180
C. hot air and a hot roller at 100-150.degree. C. are used in combination until the moisture content becomes 1% or less. It is also preferable to shrink the material by around 10% using a torque motor or the like during the drying process to improve conductivity. After drying, the fibers are allowed to shrink under moist heat. This shrinking process can dramatically improve the electrical conductivity of the fibers. Shrinkage with moist heat 100-150℃, preferably 115-130℃
Let's do it. The shrinking process can be continuous or batchwise. The important thing during processing is to avoid putting too much tension on the fibers. A shrinkage treatment method that generates a large amount of tension cannot expect much improvement in conductivity. A shrinkage rate of approximately 5 to 30% is sufficient, but the optimum value of the shrinkage rate is determined depending on the composition of the acrylic polymer, the content of the conductive elastic polymer, and the manufacturing process conditions. The fibers that have undergone the shrinking process are subjected to oiling, crimping, etc., if necessary, and are made into products in the form of filaments, tows, or staple fibers. In the fiber of the present invention, the conductive elastic polymer has a structure that is elongated but discontinuously extended in the fiber axis direction as a large number of island-like components. The presence of a large number of conductive components in the fiber cross-sectional direction and in the fiber axis direction effectively performs the functions of static elimination and discharge. In particular, since it exists in the form of elongated, discontinuous islands, having many sharp edges also seems to have the effect of improving antistatic performance. Furthermore, the use of an elastic polymer as a conductive component is also essential for maintaining antistatic performance. This is due to the everyday external forces that cause fibers to pull and bend.
When subjected to deformation, if an elastic polymer is not used as the conductive component, repeated external forces and deformation can cause cracks at the boundary between the conductive particles and the polymer containing them, resulting in a significant decrease in conductivity. have Therefore, by combining the polymers shown in the present invention, it is possible to obtain a conductive acrylic synthetic fiber that is inexpensive, has high performance, has good operability and processability, and does not lose its conductivity against external forces. The conductive acrylic synthetic fiber of the present invention does not require the use of special polymers or monomers, does not require special equipment or manufacturing processes, and has sufficiently satisfactory conductive performance, processing performance, and other product performance. It has many advantages not found in the past. In particular, the features of the fibers of the present invention include tensile strength,
One example of this is that there is no or very little decrease in conductivity with respect to external forces such as bending, and for this reason, there is no change in conductivity over time during use, and there is always good conductivity. Furthermore, fibers with a soft and supple texture unique to dry spinning can be obtained. The conductive acrylic synthetic fibers of the present invention can be used not only in clothing and interior products such as carpets, work clothes, and various uniforms that are prone to static electricity damage in daily life, but also in electronic equipment and industries that avoid static electricity damage. It is very useful as a shielding material for equipment, industrial materials, etc. The present invention will be explained in more detail below with reference to Examples. To measure the conductivity of fibers, cut a fiber bundle of 1,000 to 10,000 denier into lengths of about 5 to 15 cm, and glue both ends of the fiber bundle with conductive adhesive (DOTITE D-550 Fujikura Kasei).
Co., Ltd., and firmly grasp this part with a crimp, and apply a voltage of 100 V between them and measure the electrical resistance value R (Ω/cm). The electric specific resistance (Ω-cm) of the fiber is determined by the following formula. =R x denier/q x 10 ⁵ x specific gravity (Ω·cm) In addition, unless otherwise specified, parts and percentages shown in the examples indicate parts by weight and percentages by weight. Example 1 Acrylic polymer having a composition of acrylonitrile: methyl acrylate/sodium methallylsulfonate = 93.75:5.50:0.75 (%) and a molecular weight of 57,000 was converted into dimethylformamide (hereinafter referred to as DMF).
After solution polymerization inside and recovering and removing residual monomers,
An acrylic polymer solution with a polymer concentration of 32% was obtained. 225 parts of polyethylene adipate with a molecular weight of 750;
18 parts of 1,4-butanediol and 113 parts of diphenylmethane diisocyanate were polymerized in 356 parts of DMF, DMF was added to adjust the viscosity, and a polyurethane solution with a final polymer concentration of 15% was obtained. Carbon black (acetylene black) 100
A solution was prepared by dispersing 100 parts of DMF in 100 parts of DMF and mixed with a polyurethane solution at a ratio of 1:10 to obtain a polyurethane solution to which carbon black was added. Both solutions were mixed and stirred using a propeller type stirrer so that the ratio of polyurethane and acrylic polymer was as shown in Table 1, to obtain a spinning stock solution. The spinning stock solution was heated to a viscosity of 70 to 80 poise, and then passed through a spinneret with a hole diameter of 0.20 mm and 18 holes at a discharge rate of 35 c.c./min using a gear pump.
Spun into nitrogen at 200°C. The fibers leaving the bottom end of the spinning tube contain 5-10% residual solvent and are 488m/
It was taken up by a take-a-prowler at min. The fibers were wound onto a bobbin with a take-a-strike roller, concentrated to a total denier of 15,000 deniers, drawn 1.5 times in a DMF:water = 15:85 (%) spinning bath at 70°C, and then washed with warm water at 70°C. After applying the oil, it was dried and baked in a dryer using a combination of hot air at 150°C and hot rollers at 135°C until the moisture content became 1% or less. After drying, perform a 15% continuous shrinkage treatment at 125°C with moist heat, and then further shrink with moist heat at 120°C.
Free end heat treatment was performed at The results are shown in Table 1. In addition, when using 12 parts of carbon black dispersed in 100 parts of DMF and similarly mixed with a polyurethane solution at a ratio of 1:10,

[Table] Regardless of the ratio shown in Table 1, the conductive performance of the fibers obtained was poor. Example 2 The pore size was determined using the ExP-5 spinning stock solution of Example 1.
The material was spun into a nitrogen stream at 220° C. from a spinneret with 36 holes of 0.15 mm diameter at a discharge rate of 30 c.c./min, and wound up in the spinning draft shown in Table 2. The wound fibers were bundled to have a total denier of 6000 denier, stretched 1.4 times in a spinning bath at 70°C using DMF:water = 15:85 (%), washed with warm water at 70°C, and after applying oil to 150°C. It was dried and baked in a dryer using hot air at 135°C and heated rollers at 135°C. After drying, perform a 15% shrinkage treatment at 120°C with moist heat, and further shrink at 120°C with moist heat.
Free end heat treatment was performed at ℃. The results are shown in Table 2.

【table】

[Table] Example 3 The spun yarn of Example 1ExP-5 was bundled to a total denier of 15,000 deniers and stretched as shown in Table 3 in a spinning bath of DMF:water = 10:90 (%) at 85°C. Stretched at a magnification. After stretching, washing with water, oil adhesion,
After drying and crushing, the free end was heat-treated with moist heat at 125°C. The results are shown in Table 3.

【table】

Claims (1)

[Claims] 1. Acrylic polymer solution and conductive fine particles 10-
70% by weight of a conductive elastic polymer and 90 to 30% by weight of an elastic polymer that is miscible with the acrylic polymer but is incompatible with the acrylic polymer/conductive elastic polymer = 50 /50 to 90/10 (weight ratio) and dry-spun at a spinning draft of 20 times or less.3
1. A method for producing conductive acrylic synthetic fibers, which comprises stretching in hot water to less than twice the strength, washing with water, drying, and then shrinking under moist heat. 2. The method according to claim 1, wherein the acrylic polymer contains 80% by weight or more of acrylonitrile. 3 Acrylic polymer contains 80% by weight or less of acrylonitrile, vinyl chloride and/or vinylidene chloride
20-60% by weight. 4. The method according to claim 1, wherein the conductive fine particles are carbon black, metal, or metal oxide. 5. The method according to claim 1, wherein the conductive fine particles are tin oxide, zinc oxide, and titanium oxide coated with tin oxide or zinc oxide. 6. The method according to claim 1, wherein the elastic polymer is polyurethane. 7. The method according to claim 1, wherein the spinning draft is carried out 3 to 15 times. 8. The method according to claim 1, wherein the shrinkage is carried out at 100 to 150°C with moist heat.