JPH039206B2 - - Google Patents

Description

[Detailed description of the invention]

(1) Industrial application field The present invention provides polyester, especially polyethylene terephthalate, without impairing its thermal and mechanical properties.
The present invention relates to a method for producing antistatic polyester yarn that can impart antistatic properties to the yarn. (2) Prior Art Although polyester has excellent thermal stability and mechanical properties, it has the disadvantage that it is more likely to generate static electricity than natural fibers. Various methods have been proposed to prevent the generation of static electricity, but each has its advantages and disadvantages, and it is difficult to satisfy all of them in terms of spinning cost, antistatic property and its sustainability, fiber performance, etc. The current situation is that this has not yet been achieved. The simplest method is to apply or apply an antistatic agent to the fiber surface, but in this case, the antistatic agent tends to disappear during the dyeing process or repeated washing, so a permanent antistatic effect is not expected. There are some drawbacks that are difficult to overcome. If we focus only on the antistatic property, the durability of the antistatic effect is a fundamentally required characteristic, and in this sense, the method of kneading an antistatic agent into the polymer before spinning is preferable. Regarding this, old methods include (a) uniformly mixing polyoxyalkylene glycol into the fibers as seen in Japanese Patent Publication No. 39-5214, and (b) Japanese Patent Publication No. 47-11280 (and further Japanese Patent Publication No. 46-22200). (c) polyoxyalkylene glycol and sodium alkylbenzenesulfonate are mixed together as seen in Japanese Patent Publication No. 149247/1983), A well-known method is to use sodium alkylsulfonate in combination. In these methods, the amount of antistatic agent used is generally 2% by weight.
or more (method a), 0.7 to 8% by weight (method b), and 1.0 to
2.0% by weight (method c) is recommended, but in order to obtain a practical antistatic effect, as shown in the examples, it is recommended to use 6% by weight or more for method a, and about 7.5% by weight for method b. % by weight, method c requires a relatively large amount of agent, such as 3% by weight. On the one hand, such an increase in the amount of antistatic agent causes deterioration of the mechanical properties of the fiber itself, and at the same time, chemically, it causes a decrease in color fastness. Furthermore, the antistatic agents that are commonly used naturally have a high affinity with water, so in the case of woven and knitted fabrics that have many opportunities to come into contact with water during scouring, dyeing, or washing, the antistatic agents inside the fibers may be eluted. It falls off, and the antistatic property itself decreases rapidly. For this reason, in reality, it is necessary to use an even larger amount of antistatic agent to account for this amount of falling off, and as a result, the physical properties of the fibers continue to deteriorate. A serious defect that cannot be overlooked even in the midst of the above deterioration in physical properties is the fibrillation phenomenon particularly observed in polyester. This is because polyester fibers originally have poor compatibility with antistatic agents, and particularly when the latter is used in an amount of about 4% by weight, single fibers tend to split into fibrils, and this tendency is further accelerated by mechanical stimulation. On the other hand, as a means to prevent the deterioration of fiber physical properties, there is a composite spinning method to obtain a core-sheath structured yarn. In this method, at least two or more types of polymers are used, in which case the sheath component is a homopolymer, and the core component is the same or different polymers containing a large amount of antistatic agent, or carbon,
It is composed of a polymer containing a considerable amount of conductive material such as metal or a highly chemically modified polymer. In this type of fiber, even if the amount of antistatic agent used is reduced, an excellent antistatic effect can be obtained, and there is no effect on mechanical properties or dyeability. However, one major drawback has been pointed out in the past: As shown in the figure, there is a significant increase in the cost of spinning silk, making it unprofitable on a commercial basis. As described above, since the advent of synthetic fibers, many antistatic methods have been proposed such as coating methods, kneading methods, and composite spinning methods. However, it has not been possible to simultaneously satisfy various factors such as durability, mechanical properties, fibrillation resistance, dyeability, and spinning cost. (3) Purpose of the Invention Therefore, the purpose of the present invention is to solve the problem of antinomy between antistatic properties and mechanical and chemical properties of fibers without particularly using a composite spinning method, and thereby to provide a durable material. The purpose of the present invention is to provide an antistatic polyester fiber which has not only mechanical properties sufficient for practical use but also significantly improved fibrillation resistance, dyeability, and especially color tone (sharpness). In order to achieve the above objective, the inventors of the present invention have determined that the amount of antistatic agent used can be adjusted as much as possible in order to impart the desired functionality to a fiber made of a single component without using a composite spinning method. As a result of repeated research, we have tackled the issue of how to overcome the problem of a decrease in antistatic properties that is expected to occur as a result of having to reduce the amount of antistatic agent. It has been found that even when using this method, the anti-electrostatic property is significantly improved and the occurrence of fibrillation is reduced because it is mixed in a macro-dispersion instead of being mixed in a micro-uniform dispersion over the entire fiber cross section. (4) Structure of the Invention According to the present invention, when melt-spinning a polyethylene terephthalate polymer containing at most 3% by total weight of polyoxyalkylene glycol and an ionic antistatic agent, the melting temperature is lowered. After the polymer is completely melted at 290°C to 310°C, the spinneret temperature is set to a melting point +5°C or higher and a melting point +20°C or lower so that the birefringence of the spun yarn is 0.015 or higher, and the elongation at break is 30% or higher. Provided is a method for producing an antistatic polyester yarn, which is characterized by stretching the yarn so that it is 45% or less. Next, an example of manufacturing the antistatic polyester fiber of the present invention will be explained. Polyesters that are the basis of the fibers of the present invention include polyalkylene terephthalate, polyalkylene naphthalate, etc. Among them, the former terephthalic acid is the main acid component, and the carbon number is 2 to 6.
The present invention is directed to polyesters whose main glycol component is at least one type of glycol selected from the alkylene glycol component of ethylene glycol, trimethylene glycol, tetramethylene glycol, bentamethylene glycol, and hexamethylene glycol. Such polyester may be produced by any method; for example, for polyethylene terephthalate,
Direct esterification reaction of terephthalic acid and ethylene glycol, transesterification reaction of lower alkyl ester of terephthalic acid such as dimethyl terephthalate and ethylene glycol, or reaction of terephthalic acid and ethylene oxide, It is easily produced by producing a glycol ester of terephthalic acid and/or a low polymer thereof, and then heating the product under reduced pressure to carry out a polycondensation reaction until a desired degree of polymerization is achieved. In this polyester, a part of the terephthalic acid component may be replaced with another difunctional carboxylic acid component. Examples of such carboxylic acids include isophthalic acid, phthalic acid, dibromoterephthalic acid, naphthalene dicarboxylic acid, diphenyl dicarboxylic acid, diphenoxyethane dicarboxylic acid, β-
Difunctional aromatic carboxylic acids such as oxyethoxybenzoic acid and p-oxybenzoic acid; difunctional aliphatic carboxylic acids such as sebacic acid, adipic acid, and oxalic acid; and difunctional fats such as 1,4-cyclohexanecarboxylic acid. Examples include cyclic carboxylic acids. Further, a part of the above glycol component may be replaced with other glycol components, such as cyclohexane-1,4-dimethanol, neopentyl glycol, bisphenol A, bisphenol S, 2,2-bisphenol [3.5
-dibromo-4-(2-hydroxyethoxy)
Examples include aliphatic, alicyclic, and aromatic diol compounds such as phenyl]propane. Furthermore, the above-mentioned polyester blended with a small amount of other polymers as necessary is also included within the scope of the single component referred to in the present invention. The fiber of the present invention can be obtained from a polyester obtained by adding and blending polyoxyalkylene glycol and an ionic antistatic agent to the above-mentioned polyester. It is necessary that the polyoxyalkylene glycol has substantially no reactivity with the polyester described above. Here, "having substantially no reactivity" means not copolymerizing with polyester. When polyoxyalkylene glycol has reactivity with polyester, it becomes difficult to control the blending process. Specifically, such polyoxyalkylene glycol has an average molecular weight of 6,000 or more,
Preferably, polyoxyethylene glycol having 10,000 or more, or one containing mainly oxyethylene units (usually 50% or more) and containing, for example, oxypropylene units, is preferably used. In addition, the terminal of such polyoxyalkylene glycol may be a hydroxyl group, or may be blocked with a non-ester-forming organic group, or may be connected to other ester-forming organic groups through an ether bond, an ester bond, a carbonate bond, etc. May be combined. In the case of polyoxyalkylene glycols whose terminal ends are blocked with non-ester-forming organic groups, the average molecular weight of the polyoxyalkylene glycol may be as low as about 800 to 4,000. The content of such polyoxyalkylene glycols in the polyester is at most 2% by weight, preferably at most 1% by weight. On the other hand, the ionic antistatic agent used in combination with the polyoxyalkylene glycol is an anionic antistatic agent, a cationic antistatic agent, or a mixture thereof, such as polyethylene glycol, polybutylene glycol, polyalkyl (or aryl) or alkylaryl) sulfonic acid metal salts, polyalkyl (or aryl, or alkylaryl) amines, etc. Among the anionic antistatic agents having -SO ₃ M, especially alkyl represented by the general formula RSO ₃ M Metal salts of aryl or aralkyl sulfonic acids are preferably employed. Here, M represents an alkali metal and is usually sodium, potassium or lithium, with sodium being particularly preferred. R represents an alkyl group having 8 or more carbon atoms. In the case of an alkyl group having 7 or less carbon atoms, the compatibility with polyester becomes slightly poor. Therefore, those in which R is an alkyl group having 8 to 20 carbon atoms are usually used, and mixtures thereof are often used. The content of such alkylsulfonic acid metal salts in the polyester is at most 1.0% by weight, preferably at most 0.5%.
Weight%. From the above, considering the physical properties of the fiber, the content of polyoxyalkylene glycol and ionic antistatic agent is at most 3% by weight, preferably 1.5% by weight, particularly preferably 1.2% by weight. (Weight) The former preferably accounts for 50 to 90% by weight. The lower limit is at least 0.2% by weight; below this, the desired antistatic effect cannot be expected no matter how you change the proportion of the two used or the hollowness ratio of the fibers. . Any method can be used to blend the polyoxyalkylene recall and the ionic antistatic agent into the polyester, and both can be blended into the polyester at the same time or in any order. That is, any stage until the end of polyester spinning,
For example, before the polycondensation reaction of polyester starts, during the polycondensation reaction, at the end of the polycondensation reaction and still in the molten state, in the powder state, in the spinning stage, etc.
Both may be added at the same time or in any order.
Also, even if both are melted and mixed in advance and then added, the 2
They may be added in multiple portions, or they may be separately blended into the polyester and then mixed before molding or the like. Furthermore, when it is added before the middle stage of the polycondensation reaction, it may be added after being dissolved or dispersed in a solvent such as glycol. Next, the polyester obtained as described above is spun, which will be explained using the drawings. Fig. 1 is a schematic diagram of a spinning device normally used for melt spinning, in which polyester is put in a popper (1) in the form of chips, melted by an extruder (2), measured arbitrarily by a gear pump (4), and passed through a conduit (5). , the polymer is sent to the pack 7 attached to the heating pot 6, is discharged from the nozzle 8 provided on the pack, and is cooled by the cooling air blowing device 9,
Next, an oil agent is applied by 10 oiling rollers, and taken up by 11 Godet rollers,
12 windings are completed. In the present invention, the complete melting temperature of 290 DEG C. to 310 DEG C. is the polymer temperature at the final outlet of the extruder 2, which is usually the temperature measured before the gear pump 4. The structure of the spinneret is important to carry out the present invention, and the spinneret usually has a cross section as shown in Figure 2, and the spinneret temperature is measured by inserting a thermocouple etc. into the 14 pores. Ru. When using such a die, the temperature of the die cannot be lowered very much, and it varies depending on the yarn denier, spinning speed, [η] of the polyester, degree of copolymerization, and additives. In the case of normal polyester with [η] around 0.6,
When it is not completely melted, a cap temperature of 275℃ or higher is required, but if it is completely melted and the temperature is 290℃ or higher.
It is possible to lower the temperature to around 270℃, but if it is lowered any lower than this, thread breakage and lapping may occur, causing process troubles. Therefore, a conventional cap as shown in FIG. 2 is not suitable for carrying out the present invention. To carry out the present invention, as shown in FIG. 3, a thin tube 15 protrudes several mm or more, preferably nearly 10 mm, from the mouth surface, and this thin tube has a normal spinning hole such as 13. preferred and pore 1
The present invention can be carried out smoothly by setting the temperature of the cap at step 4 to a melting point of +5°C to +20°C. When such a die is used, the minimum spinning temperature can be lowered, which is something that has not been known up to now. In addition, as another type of nozzle, as shown in Fig. 4, a needle-like object such as 16 is provided in the center of the spinning hole of the nozzle, and the needle-like object such as 16 is provided in the center of the spinning nozzle, and the needle-like object 14 is made to protrude from the nozzle surface.
By lowering the temperature of the nozzle shown in FIG. 2 below that of the nozzle shown in FIG. 2, almost the same stringability as that of the nozzle shown in FIG. 3 can be obtained. The spindle shown in FIG. 4 is characterized in that the polymer is wrapped around 16 needles in an icicle-like conical shape, as shown in the figure, for spinning. The length of this needle from the base surface is arbitrary, but it is several mm or more, preferably 3 mm or more. Even if such a die as shown in Figures 3 and 4 is used, the melting temperature needs to be 290℃ or higher, and it is necessary to lower it to about 285℃.
In addition, when the mouthpiece temperature is lowered within the range of the present invention, yarn breakage,
Lap may occur and cause process trouble. Using the above-mentioned preferred die, the spinning hole △n is 0.015.
It is sufficient to take the product in the above manner, but in order to increase this Δn, it is sufficient to increase the spinning speed, lower the die temperature, or increase the length of the capillary tube or the length of the needle. As can be understood from the above explanation, when carrying out the present invention, △n naturally becomes higher than that obtained under normal spinning conditions when compared at a constant spinning speed, and this structural change occurs during the subsequent drawing process or at the same time as the drawing process. It is thought that even through the false-twisting process, the orientation of the amorphous portion decreases, resulting in a structure that has antistatic properties and anti-fibrillation properties, and the orientation of the crystalline portion provides mechanical strength. However, even in the present invention, if the stretching or false twisting is carried out at a high draw ratio that lowers the elongation too much, the antistatic properties and fibrillation resistance will be worse than those of the conventional ones. The elongation should be within 30-45%. It goes without saying that the present invention is not limited to the caps illustrated in the drawings, and can be applied not only to drawn filament yarns and false twisted yarns, but also to stable fibers. It goes without saying that the present invention includes not only spinning, but also a direct stretching method in which a stretching step is performed subsequent to spinning. (5) Actions and Effects The present invention departs from the conventional concept of uniformly micro-dispersing a large amount of antistatic agent in fibers and achieves a high degree of antistatic effect by macro-dispersing a small amount of antistatic agent. The first technical idea is to obtain. The conventional technique of adding a large amount of antistatic agent to prevent fibrillation due to friction is very disadvantageous, but using a small amount of the antistatic agent as in the present invention is also effective in terms of fibrillation resistance. Further, the present inventors conducted various studies on fiber structures that improve fibrillation resistance and found that the smaller the birefringence of the yarn after drawing heat treatment, the better the fibrillation resistance. Therefore, even in the prior art, fibrillation resistance can be improved by loosening the stretching conditions and increasing the elongation, but it is not possible to use a material with a high elongation for practical use. Therefore, there is an appropriate range of elongation, and if the elongation is within this appropriate range, fibril resistance cannot be obtained with the prior art. The present invention also provides a spinning technique for imparting a fibril-resistant fiber structure to the yarn. In order to produce a yarn that has this electrical properties and also has fibrillation resistance, it is necessary to disperse the small amount of antistatic agent more effectively. On the other hand, the compatibility is poor, and therefore the fibril resistance is poorer than when no additive is added, so the yarn must have a fibrous structure that improves the fibril resistance. Therefore, it is necessary to completely melt the polyethylene terephthalate polymer containing at most 3% by weight. Its melting temperature is a complete melting temperature of 290°C to 310°C. This temperature is determined by the intrinsic viscosity [η].
Of course, it is different, but the [η] used in the clothing field is usually around 0.5 to 0.7, and the melting temperature of polyester tire cords with [η] of 0.8 to 1.0 is
Although the temperature can reach 320°C to 340°C, the present invention is not intended for these. For a normal [η], a melting temperature of 280 to 290°C is sufficient, but in the present invention, the spinneret temperature for normal polyester melt spinning is
Compared to 280°C to 295°C, the temperature of the cap should be set to +5 to the melting point.
℃ to 20℃ (usually 260℃ to 275℃), and in order to maintain spinnability (the yarn can be spun without wrapping, yarn breakage, etc.) at this spinning temperature, the temperature must be 290℃ to 310℃.
A full melting temperature of °C is required. Normally [η]
If the melting temperature is 310°C or higher, [η] decreases significantly, the quality of the filament deteriorates, and intrafusal spots occur. By spinning at the low spinning temperature mentioned above, the fibrillation resistance of the drawn yarn can be improved, but in order to make this fibrillation resistance even more effective, the △n of the spun yarn must be 0.015 or more. Preferably, it is 0.06 or more, and the elongation of the drawn yarn must be kept at a relatively high elongation of 30% or more and 45% or less for a drawn yarn. To further explain these effects, as the spinning temperature is lowered, △n of the spun yarn increases and its elongation decreases, and as the spinning speed is increased, △n increases and the elongation decreases. do. Although the fibrillability can be considerably improved by combining the spindle temperature and high spinning speed technology of these conventional techniques, in order to achieve more effective results, the spinneret temperature must be adjusted to the spinning limit temperature, which has been said up until now, or to the weak yarn (usually 275°C in the case of polyester) is further lowered than the melting temperature of the polymer (usually 275°C in the case of polyester, which is the lower limit spinneret temperature for continuous spinning) and the melting point of the polymer is +5°C to +20°C (usually 260°C to 275°C).
The desired antistatic properties and anti-fibrillation properties can be obtained by spinning within the range of .DELTA.n and at least 0.015. The structure of this low-temperature spun product is different from that of ordinary high-speed spun products, for example, Δn is the same as Δn obtained by high-speed spinning.
obtained under the conditions of the present invention, these yarns are subjected to the same drawing heat treatment, and the structure of the drawn yarns or the yarns obtained by changing the draw ratio to obtain the same elongation is analyzed. has a high dyeability, the peak position of the mechanical loss tangent (Tanδ) with respect to temperature is on the low temperature side, and the peak area is also large, and X-ray analysis shows that the crystal part is well oriented and crystallized. but,
It can be seen that the orientation of the amorphous portion is lowered. It is thought that this low orientation of the amorphous portion causes the micro-uniform dispersion of the antistatic agent to become macro-dispersed, allowing a small amount to exhibit an antistatic effect and also providing anti-fibrillation properties. In the present invention, when the elongation of the drawn yarn is set to a high draw ratio of 20% or less, the antistatic agent becomes elongated and more uniformly dispersed in the fiber axis direction due to the highly oriented amorphous portion, which improves antistatic properties. Not only this, but also the fibril resistance deteriorates. Therefore, in order to eliminate these drawbacks, the elongation of the yarn needs to be between 30% and 45%. If the elongation exceeds 45%, it may cause sink marks during fabric formation or creep during use, leaving mechanical problems. The present invention will be explained in detail with reference to Examples below. Incidentally, the measured values in the examples were determined by the following method. (1) Charged frictional pressure (i) Equipment and materials Rotating drum type frictional charge measuring device (rotary static tester) Oscilloscope Friction cloth Cotton broad 30/- scouring bleached and glue-free finish (ii) Preparation of test piece Winding type: 3.8 cm x 3.0cm Gold frame type: 4.0cm x 8.0cm Collect 3 pieces in each length. Furthermore, a cotton broadcloth (30/-) of friction cloth, 2.5cm x 14.0cm,
Harvest 3 pieces vertically. (iii) Test procedure Humidity control: Leave in a desiccator at 65±2% RH for at least one day and night. Atmosphere of measurement chamber: 20±2℃, 65±2%RH Sample: Number of sheets stacked: 1 Drum rotation speed: 700r.pm Charging equilibrium time: 1 minute Contact pressure load: 600g Place one test piece face up. It is attached to the rotating drum of a rotary static, and a piece of friction cloth is attached to the clips at both ends of the lower part in parallel at the position where it contacts the test piece, and a load of 600 g is applied. Operate the recorder (5cm/mm) - rotating drum - oscilloscope in this order, and when the charging equilibrium is reached, the frictional charging voltage (V)
and extreme values (+, -) followed by the average value of the three images. (Up to the 10th integer place) Regarding the relationship between the antistatic effect and the frictional charging voltage, the antistatic effect will be achieved if the latter is approximately 2000V (preferably 1000V) or less. (2) Mechanical damage to fibers (fibrils);
Using a JISL0823 friction tester type, stack two test pieces and set them on the test piece stand, use Tetron Georgette crepe fabric (white) instead of white cotton cloth, and apply a load of 500.
g. Visually check the state of fibrils after 500 reciprocations; rank 5 as no fibrils are observed, and rank 4, 3, 2, and 1 as the amount of fibrils generated increases. and
The practical range has been set to grade 3 or above. Example 1 98.8 parts by weight of polyethylene terephthalate with an intrinsic viscosity of 0.65 measured at 25°C in orthochlorophenol, a 2:1 mixture of polyoxyethylene glycol with an average molecular weight of 20,000 and sodium alkyl sulfonate with an average carbon number of 12 to 13 to prevent static electricity. The melting point of 1.2 parts by weight of mixed polyethylene terephthalate is 255
It was warm at ℃. The spinning device shown in Figure 1 was used to completely melt the yarn at 295°C. Using a spindle with a hole diameter of 1.3φ and a land length of 2mm with a needle of 1.0φ and a protruding length of 4mm from the spindle inserted in the center, the spindle temperature was varied and the spinning speed was varied to vary △n. The spun yarn was drawn using a conventional drawing machine at a supply roller temperature of 85°C and a drawing set roller temperature of 160°C, and the drawing ratio was varied to vary the elongation of the drawn yarn. At this time, the spinning discharge rate was changed and adjusted so that the fineness of the drawn yarn was 50±2 de. Three of these drawn yarns were knitted using a 20G knitting machine into a cotton jersey with a basis weight of approximately 110g/ ^m2 , and then dry heated at 180°C.
x 1 minute to obtain gray fabric, which was boiled in a 3% caustic soda aqueous solution to reduce its weight by about 10%, and after washing with water, dye (Dianix Black from Mitsubishi Chemical
-HG-FS) 10% OWF and nonionic dispersant (Meisei Chemical Industry Disper VG) 0.5g/bath ratio 1:50
for 1 hour at 130°C, and then treated with a neutralizing agent (Bisnhol P).
-70), washed, air dried, and then dried with hot air at 80°C for about 1 hour. For washing, use an automatic reversing washing machine and add 40g of commercially available synthetic detergent Zabu to 40℃ warm water.
Table 1 shows the results of antistatic and fibril resistance tests on samples that were washed for 20 minutes and then rinsed with running water for 20 minutes.
It's like this.

【table】

Claims (1)

[Claims] 1. When melt-spinning a polyethylene terephthanate polymer containing at most 3% by total weight of polyoxyalkylene glycol and an ionic antistatic agent, the melting temperature is set at 290°C to 310°C,
After the polymer is completely melted, the temperature of the mouthpiece is set to the melting point +
The birefringence of the spun yarn is 5℃ or more and melting point + 20℃ or less.
The elongation at break of the yarn spun to be 0.015 or more is 30.
A method for producing antistatic polyester yarn, characterized by stretching the yarn so that the yarn is drawn at % or more and 45% or less.