JPH0874125A - Electrically conductive polyester monofilament and its woven fabric for industrial purpose - Google Patents

Abstract

PURPOSE: To obtain an electrically conductive polyester monofilament which has performance suitable for woven fabrics for industrial purposes, for example, a sieving filter for powdery materials such as wheat flour, drier belts on the production of sanitary products such as paper diapers or sanitary napkins or drier canvas for a paper-making machine. CONSTITUTION: This electrically conductive polyester monofilament comprises 4-15wt.% of a high-conductivity carbon black and 96-85wt.% of a polyester composition containing the followings (A) and (B):(A)30-90wt.% of a polyethylene terephthalate and (B) 70-10wt.% of a polyester copolymer containing 90-98wt.% of butylene terephthalate units and/or 10-2wt.% of dibutyl aliphatic dicarboxylate units.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductive polyester monofilament and an industrial fabric using the conductive polyester monofilament and having excellent antistatic properties.

[0002]

2. Description of the Related Art Generally, thermoplastic polyesters such as polyethylene terephthalate have excellent mechanical properties and chemical properties, and have been widely used as molded articles such as fibers and films.

However, since polyester itself has extremely low conductivity, it has various problems due to the fact that it is easily charged with static electricity. For example, using a polyester monofilament, a powder sieving filter such as wheat flour, a dryer belt for drying water and organic solvents during the production of sanitary products such as diapers and sanitary products, and industrial fabrics such as a dryer canvas of a paper machine, The static electricity generated during use accumulates on the fabric, causing the risk of dust adhesion to the product and ignition / explosion due to discharge sparks, thus impairing operation.

Conventionally, various improvements have been attempted in order to deal with this kind of problem. For example, an industrial fabric in which a metal wire such as a copper wire is woven in a part of a polyester monofilament fabric is known. However, this is not practical because there are problems such as rusting of the metal wire during use and rubbing of the roller with which the fabric contacts.

Further, an industrial woven fabric in which a conductive core-sheath nylon monofilament using a conductive nylon resin composition obtained by blending conductive carbon black in a high concentration as a sheath component is interwoven with a polyester monofilament woven fabric has also been used. However, in this case, the polyester monofilament and the conductive core-sheath nylon monofilament have different dimensional stability when absorbing moisture, so that not only undulation occurs in the fabric during use in a dryer, but also carbon black is blended in a high concentration. Due to the poor fluidity of the nylon resin composition, there is a problem that a uniform conductive core-sheath nylon monofilament cannot be obtained.

Various proposals have been made for means for imparting electrical conductivity to polyester fibers. For example, a polyester mixture containing an aromatic polyester / aliphatic polyester as a core component (mixing weight ratio 80/20 to 98/2) and A conductive composite fiber composed of a composition with conductive carbon black and having a sheath component made of an aromatic polyester has been proposed (JP-A-56-85423). However, this conductive composite fiber is used as a sheath component. Since the conductive carbon black does not exist, the conductivity is insufficient, and since it is necessary to mix the carbon black in a large amount of substantially 20 to 30% by weight, stains around the spinneret hole are not formed during the composite spinning. However, there is a problem in that stable production is difficult for a long time.

[0007]

SUMMARY OF THE INVENTION The present invention has been achieved as a result of studying how to solve the above-mentioned problems in the prior art. Therefore, an object of the present invention is to provide a powder sieving filter such as wheat flour, a dryer belt for drying water or an organic solvent during the production of sanitary products such as paper diapers and sanitary products, and industrial fabrics such as a dryer canvas of a paper machine. An object of the present invention is to provide a conductive polyester monofilament having suitable performance and various industrial textiles using the monofilament.

[0008]

The objects of the present invention described above can be achieved by the following constitutions. A conductive polyester monofilament comprising 4 to 15% by weight of highly conductive carbon black and 96 to 85% by weight of a polyester composition comprising the following (A) and (B). (A) Polyethylene terephthalate 30 to 90 wt% (B) Butylene terephthalate unit and / or butylene isophthalate unit 90 to 98 wt% and dibutyl ester unit of aliphatic dicarboxylic acid 10 to 2 wt% Copolymerized polyester 70-1
0% by weight In addition, the highly conductive monofilament of the present invention comprises the composition comprising (A), (B) and (C) as a sheath component,
(D) A core-sheath composite type conductive polyester monofilament containing an aromatic polyester as a core component.

The present invention will be described in detail below. In the polyethylene terephthalate (hereinafter referred to as PET) (A) which is a constituent component of the polyester mixture of the present invention, 80 mol% or more of the dicarboxylic acid component is terephthalic acid and 80 mol% or more of the glycol component is ethylene glycol. Polyester, each of which is less than 20 mol% of a copolymerization component as a dicarboxylic acid component or a glycol component, for example, naphthalene-2,6-dicarboxylic acid, 5-
Dicarboxylic acid components such as sodium sulfoisophthalic acid, polyvalent carboxylic acid components such as trimellitic acid and pyromellitic acid, oxycarboxylic acid components such as p-oxyethoxybenzoic acid, and tetramethylene glycol, hexamethylene glycol, diethylene glycol, propylene Glycol, neopentyl glycol, polyoxyalkylene glycol, p-xylylene glycol,
It may contain a diol component such as 1,4-cyclohexanedimethanol and 5-sodium sulforesorcin. The PET has an intrinsic viscosity [η] of usually 0.6 or more, but when the conductive polyester monofilament of the present invention is used for a paper dryer canvas or the like, it has a durability of 0.68 or more from the viewpoint of durability. It is advantageous to use one. Here, the intrinsic viscosity in the present invention means
25 in phenol / tetrachloroethane (1/1) solution
The copolymerized polyester (B), which is the other constituent component of the above polyester mixture of the present invention represented by [η], is a butylene terephthalate unit and / or a butylene isophthalate unit 90
-98% by weight, in particular 97-93% by weight, and 10-2% by weight of dibutyl ester units of aliphatic dicarboxylic acids,
Particularly, it is a copolyester composed of 7 to 3% by weight of a copolymerization component. If the copolymerization ratio of the dibutyl ester unit of the aliphatic dicarboxylic acid in this copolyester is less than 10% by weight, spinning disorder due to insufficient fluidity will occur, and if it is more than 98% by weight, melt spinning will occur during melt spinning. It is not preferable because stains tend to adhere to the periphery of the spinneret discharge holes and the monofilament wire diameter unevenness tends to increase. The intrinsic viscosity [η] of the copolyester may be usually 0.3 or more.

The dibutyl ester unit of the aliphatic dicarboxylic acid in the copolyester is preferably a dibutyl ester unit of a dicarboxylic acid having a methylene number of 3 to 10, and among these, a dibutyl adipate unit is particularly preferable.

The monofilament of the present invention contains a mixture of the above-mentioned (A) PET and (B) copolyester as a resin component.

The mixing ratio of PET to the copolymerized polyester in the polyester mixture is 30 to 90% by weight of the PET, especially 55 to 75% by weight, and 70 to 10% by weight of the copolymerized polyester, especially 45 to 25% by weight. Must be in range. 90% by weight of PET
If it is more than 30% by weight, the conductivity and fluidity will decrease.
If the amount is less than the above range, the strength of the monofilament decreases, which is not preferable.

The conductive monofilament aimed at by the present invention has a composition in which a specific amount of (C) highly conductive carbon black is blended with a polyester mixture consisting of (A) PET and (B) copolyester. It is obtained by making the material a fiber material. The high conductivity carbon black (C) contained in the polyester monofilament of the present invention has a DBP oil supply amount (9 g method) of 340.
Furnace-based carbon black of m / 100 g or more. Examples of such carbon black include "Ketjen Black" (trademark) EC and "Ketjen Black" manufactured by Ketjen Black International.
(Trademark) EC600JD can be mentioned. In addition,
As carbon black, DBP lubrication amount is 300m
An acetylene black of 100 g / 100 g or less is also known, which is the above-mentioned "Ketjenblack" (trademark) E.
The conductivity is lower than that of C and the like, and in order to obtain satisfactory conductivity by using acetylene black, for example, about 3 times the addition amount of "Ketjenblack" (trademark) EC is required, and the flow rate of polyester is increased. It cannot be used because it deteriorates the property.

The amount ratio of the above polyester composition, which is a constituent material of the monofilament of the present invention, to the highly conductive carbon black is 4 to 15% by weight of the highly conductive carbon black based on 96 to 85% by weight of the polyester mixture. Percentage Here, when "Ketjen Black" (trademark) EC is used as the carbon black, a range of 7 to 15% by weight is particularly preferable, and when "Ketjen Black" (trademark) EC600JD is used as the carbon black, 4 to 8 wt% is used. % Range is particularly preferred. When the amount of the highly conductive carbon black is more than 15% by weight, the fluidity of the resin is lowered, and not only the variation in the wire diameter of the obtained monofilament (hereinafter referred to as wire diameter unevenness) becomes large but also the melt spinning becomes difficult. If it is less than 4% by weight, the conductivity of the obtained monofilament becomes insufficient, which is not preferable.

The highly conductive carbon black and the polyester mixture can be mixed by a known method, for example, by kneading under heating with a twin-screw kneading extruder or a dough mixer. Further, (A) polyethylene terephthalate in the polyester mixture,
The (B) copolymerized polyester may be mixed before kneading with the highly conductive carbon black, but the (A) polyethylene terephthalate chip and the (B) copolymerized polyester chip may be mixed with the (C) highly conductive resin. It is also possible to knead simultaneously with carbon black. Further, (C) the highly conductive carbon black and (B) the copolyester chip may be kneaded and then the (A) polyethylene terephthalate chip may be kneaded.

The conductive polyester monofilament for the purpose of the present invention is a composition obtained by kneading (A) PET, (B) copolymerized polyester and (C) highly conductive carbon black in a predetermined ratio by melt spinning, Although obtained by stretching, in the case of a core-sheath composite type conductive polyester monofilament having the composition comprising (A), (B) and (C) as a sheath component and (D) an aromatic polyester as a core component, The strength of the monofilament becomes excellent.

The (D) aromatic polyester as the core component in the core-sheath composite conductive polyester monofilament is mainly composed of a difunctional component such as aromatic dicarboxylic acid or its dialkyl ester and a glycol component. However, a material mainly composed of PET is preferable. This PET-based polyester may be a homopolyester or a copolyester, and examples of the copolymerization component include adipic acid, sebacic acid, phthalic acid, naphthalene-2,6-dicarboxylic acid, and 5-sodium. Dicarboxylic acid components such as sulfoisophthalic acid, polycarboxylic acid components such as trimellitic acid and pyromellitic acid, oxycarboxylic acid components such as p-oxyethoxybenzoic acid, and tetramethylene glycol, hexamethylene glycol, diethylene glycol, propylene glycol , Neopentyl glycol,
A diol component such as polyoxyalkylene glycol, p-xylylene glycol, 1,4-cyclohexanedimethanol, and 5-sodium sulforesorcin may be contained. Further, inorganic particles such as titanium oxide, silica and alumina may be added depending on the purpose.

The intrinsic viscosity of the above-mentioned (D) aromatic polyester is usually 0.6 or more, but when the conductive polyester monofilament of the present invention is used for a paper dryer canvas or the like, from the viewpoint of durability. Especially 0.
It is advantageous to use more than 68.

The electrically conductive polyester monofilament of the present invention is a continuous yarn consisting of one single yarn, and may have any shape such as one having a cross-sectional shape such as a circle, a triangle, a square, or a regular polygon.

The diameter of the cross section of the monofilament can be appropriately selected depending on the application, but the range of 0.05 to 3 mm is most preferably used. The required strength of the monofilament varies depending on the use, but it is preferably about 3.0 g / denier or more.

The electroconductive polyester monofilament and the core-sheath composite electroconductive polyester monofilament of the present invention can be produced by a known spinning method without requiring any special method.

However, when the conductive polyester monofilament of the present invention is a core-sheath composite type, the composite ratio of core component: sheath component is 50:50 to 95: 5, particularly 60:40.
It is necessary to be 85:15 (weight ratio). When the ratio of the sheath component exceeds 50 parts by weight, the conductivity is improved, but the strength of the monofilament decreases, and when the ratio of the sheath component is less than 5 parts by weight, the conductivity becomes insufficient, and thus both are preferable. Absent.

The conductive polyester monofilament and the core-sheath composite type conductive polyester monofilament of the present invention thus obtained have sufficient conductivity and sufficient yarn physical properties, and are therefore suitable as antistatic wire rods for various industrial fabrics. It is useful.

When the conductive polyester monofilament and core-sheath composite conductive polyester monofilament of the present invention are used for sieving filters of edible powder such as wheat flour, rice flour and various starches,
When the outer layer of these monofilaments is further coated with a resin such as polyester, polyamide, polyolefin, epoxy resin, or fluorine resin that does not contain conductive carbon black (hereinafter referred to as surface coating), black debris that rarely occurs is edible powder. Since it can be prevented from being mixed into the body, favorable results are obtained. As the surface coating method in this case, a known triple core-sheath composite spinning method, coating, or the like can be adopted.

The industrial woven fabric of the present invention is various industrial woven fabrics which are woven by using the above-mentioned conductive polyester monofilament or core-sheath composite conductive polyester monofilament in at least a part of the weft and / or the warp constituting the woven fabric. Is.

The weave method of this industrial woven fabric can be appropriately selected depending on the intended use. For example, plain weave, twill weave, 2
Known weaving methods such as double weaving and triple weaving can be adopted.

The industrial woven fabric of the present invention can be used for various purposes because it can prevent damages caused by electrification during use. For example, powder sieving filters such as wheat flour, disposable diapers and physiological products. Can be suitably used as a dryer belt for drying water or an organic solvent at the time of producing a sanitary product, and an industrial fabric such as a dryer canvas of a paper machine.

[0028]

The present invention will be described in more detail with reference to the following examples. In addition, the electrostatic voltage measuring device EA-03 manufactured by Rion Co., Ltd. was used to measure the electrostatic voltage during running of the fabric in the examples, and the endless fabric was placed on two rollers for 360 m.
The electrification voltage when running for 2 minutes at a speed of / min was measured from a distance of 10 cm.

For the wire diameter unevenness in the examples, a monofilament sample of 300 m was measured at a speed of 30 m / min using a laser outer diameter measuring instrument KL-151A manufactured by Anritsu Corporation, and the maximum measured value was obtained. This is the difference between the value and the minimum value.

[Examples 1 to 3, Comparative Examples 1 and 2] Intrinsic viscosity of 0.70 (measured in a mixed solvent of phenol and tetrachloroethane 1: 1 at 25 ° C) dried under vacuum at 160 ° C for 8 hours. PET chips, butylene terephthalate unit 65.3% by weight, butylene isophthalate unit 30.1
Wt% and a copolymerized polyester ([η] 0.50) consisting of 4.6 wt% of butylene adipate units in the proportions shown in Table 1, 90 parts by weight of chips and "Ketjenblack" EC (Ketjen Black International Co., Ltd. product (hereinafter referred to as KB-EC)) 10 parts by weight was kneaded with a twin-screw kneading / extruding machine at 285 ° C. for about 3 minutes, and then extruded into a gut shape,
After cooling, cutting was performed to obtain carbon black-containing polyester composition chips.

Next, the above-mentioned carbon black-containing polyester composition chips are dried at 150 ° C. for 8 hours, and melt spinning is performed by a conventional method using an extruder type melt spinning machine having a spinning head at the tip of the extruder.
A conductive polyester monofilament having a circular cross section of 0.3 mm was obtained. Table 1 also shows the measurement results of the conductivity (specific resistance), the wire diameter unevenness, and the strength of the obtained monofilament.

[0032]

[Table 1] [Examples 4 to 5, Comparative Examples 3 to 4] Obtained in the same manner as in Example 1 except that the copolymerization composition of the copolymerized polyester used in Example 1 was changed as shown in Table 2. Table 2 also shows the evaluation results of the monofilaments (specific resistance, stain around the spinneret, melt spinning). Table 2 also shows the results of Example 1.

[0033]

[Table 2] Examples 6 to 9 and Comparative Examples 5 to 6 The same as Example 1 except that the mixing ratio of KB-EC and the polyester composition in Example 1 was changed as shown in Table 3. Table 3 also shows the evaluation results (resistivity, linear unevenness) of the monofilaments obtained by performing the tests. Table 3 also shows the results of Example 1.

[Example 10 and Comparative Example 7] The conductive carbon black KB-EC in Example 1 was replaced with KB-
Change to ECJ and change the amount of conductive carbon black to 6
The evaluation result of the monofilament obtained in the same manner as in Example 1 except that the weight% was changed is also shown in Table 3 as Example 10. Further, the evaluation result of the monofilament obtained in the same manner as in Example 1 except that the conductive carbon black KB-EC in Example 1 was changed to AB is also shown in Table 3 as Comparative Example 7. .

[0035]

[Table 3] [Example 11] As a core component, a PET chip having an intrinsic viscosity of 0.94 (measured in a mixed solvent of phenol and tetrachloroethane 1: 1 at 25 ° C) dried at 160 ° C under vacuum for 8 hours was prepared.

On the other hand, as the sheath component, used in Example 1,
A carbon black-containing polyester composition chip was prepared. Core-sheath composite spinning of the above-mentioned carbon black-containing polyester chip for the sheath component and PET chip for the core component was carried out by a conventional method using a composite spinning machine having two extruders, and the diameter was 0.3 mm, and the core / sheath composite weight was Ratio 7
A conductive polyester monofilament having a circular cross section of 0/30 was obtained. Table 4 shows the evaluation results of the conductivity (specific resistance) and the wire diameter unevenness of the obtained monofilament.

[Examples 12 to 15, Comparative Examples 8 to 9]
Except that the mixing ratio of KB-EC and the polyester composition in Example 11 was changed as described in Table 4,
Table 4 shows the evaluation results (resistivity, linear spots) of the monofilament obtained by performing in the same manner as in Example 11. In addition, Table 4 also shows the results of Example 11.

Example 16 and Comparative Example 10 Example 1
1 conductive carbon black KB-EC, KB-EC
Example 16 shows the evaluation results of the monofilament obtained in the same manner as in Example 11 except that the amount of the conductive carbon black was changed to J and the amount of the conductive carbon black was changed to 6% by weight. Moreover, the evaluation result of the monofilament obtained in the same manner as in Example 11 except that the conductive carbon black KB-EC in Example 11 was changed to AB is also shown in Table 4 as Comparative Example 10.

[0039]

[Table 4] [Examples 17 to 18, Comparative Examples 11 to 12] Example 1
Table 5 shows the evaluation results of monofilaments obtained in the same manner as in Example 1 except that the copolymerization composition of the copolymerized polyester in Example 1 was changed as described in Table 5. In addition, Table 5 also shows the results of Example 11.

[0040]

[Table 5] [Examples 19 to 20, Comparative Examples 13 to 14] Example 1
Table 6 shows the evaluation results of monofilaments performed in the same manner as in Example 11 except that the mixing ratio of PET and the copolyester of the polyester mixture in 1 was changed as described in Table 6. The results of Example 11 are also shown in Table 6.

[0041]

[Table 6] [Examples 21 to 22, Comparative Examples 15 to 16] Example 1
Table 7 shows the evaluation results of monofilaments performed in the same manner as in Example 11 except that the core-sheath composite ratio in 1 was changed as described in Table 7. In Table 7, Example 1
The results of No. 1 are also shown.

[0042]

[Table 7] [Examples 23 to 26, Comparative Example 17] A circular plain monofilament having a diameter of 0.3 mm and made of PET alone was used as a warp, and the conductive monofilament obtained in Example 1 was used as a weft to prepare a plain fabric having a width of 5 cm. . The result of measuring the electrification voltage during running of this fabric by the method described above is shown in Table 8.
(Example 23).

Further, the evaluation results of the woven fabric obtained in the same manner as in Example 23, except that the weft yarn in Example 23 was changed to the core-sheath composite type conductive monofilament obtained in Example 11, are shown in Table 8. (Example 24).

Further, the evaluation results of the woven fabric obtained in the same manner as in Example 23 except that the conductive monofilament obtained in Example 1 was used for both the warp and the weft are also shown in Table 8 (implementation). Example 25).

Similarly, Table 8 shows the results of the woven fabric obtained in the same manner as in Example 23, except that the core-sheath composite type conductive monofilament obtained in Example 11 was used in both the warp and the weft. It is described together (Example 26).

For comparison, a plain fabric having a width of 5 cm was prepared by using a monofilament having a circular cross section of φ0.3 mm, which was made of PET alone for both the weft and the warp, and the charging voltage during running was similarly measured. Yes (Comparative Example 1)
7).

[0047]

[Table 8]

[0048]

INDUSTRIAL APPLICABILITY The conductive polyester monofilament and core-sheath composite type conductive polyester monofilament of the present invention have sufficient conductivity and thread properties, and are useful as antistatic wire rods for various industrial fabrics. is there.
In addition, the industrial fabric using the conductive polyester monofilament or core-sheath composite type conductive polyester monofilament of the present invention has an excellent antistatic effect, for example, a powder sieving filter such as wheat flour, a paper diaper or a physiological product. Can be suitably used as a dryer belt for drying water or an organic solvent at the time of manufacturing a sanitary product, and various industrial fabrics used in processes such as a dryer canvas of a paper machine that are easily charged.

Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical display location D21F 7/08 A (72) Inventor Tadanori Iwama 1 Kawara, Showa-cho, Okazaki-shi, Aichi Toray Monofilament Co., Ltd.

Claims (7)

[Claims] 1. A conductive polyester monofilament comprising 4 to 15% by weight of highly conductive carbon black and 96 to 85% by weight of a polyester composition comprising the following (A) and (B). (A) Polyethylene terephthalate 30 to 90 wt% (B) Butylene terephthalate unit and / or butylene isophthalate unit 90 to 98 wt% and dibutyl ester unit of aliphatic dicarboxylic acid 10 to 2 wt% Copolymerized polyester 70-1
0% by weight 2. A polyester composition 96 comprising the aromatic polyester as the core component, 4 to 15% by weight of highly conductive carbon black as the sheath component, and the following (A) and (B):
85% by weight of core-sheath composite type conductive polyester monofilament. (A) Polyethylene terephthalate 30 to 90 wt% (B) Butylene terephthalate unit and / or butylene isophthalate unit 90 to 98 wt% and dibutyl ester unit of aliphatic dicarboxylic acid 10 to 2 wt% Copolymerized polyester 70-1
0% by weight 3. The core-sheath composite type conductive polyester monofilament according to claim 2, wherein the composite ratio of the core-sheath is 50:50 to 95: 5 by weight ratio of the core component and the sheath component. 4. The industrial use, characterized in that the conductive polyester monofilament or core-sheath composite conductive polyester monofilament according to any one of claims 1 to 3 is used for at least a part of the weft yarn and / or the warp yarn. fabric. 5. The industrial fabric according to claim 4, which is applied to a powder skewer filter. 6. The industrial woven fabric according to claim 4, which is applied to a dryer belt for producing a sanitary product. 7. The industrial fabric according to claim 4, which is applied to a dryer canvas of a paper machine.