JP3200882B2 - Polyester monofilament - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyester monofilament excellent in abrasion resistance and a papermaking wire using the polyester monofilament.

2. Description of the Related Art In general, thermoplastic polyesters such as polyethylene terephthalate have excellent mechanical and chemical properties and have been widely used as molded articles such as fibers and films. However, if the polyester monofilament is used in industrial applications where it comes into contact with other substances, such as particles and structures such as metals, ceramics and plastics, it is susceptible to abrasion damage by these particles and structures, and therefore polyester Nets and woven fabrics using monofilaments have a shortcoming that their life as products is short. For example, in the paper industry,
Conventionally, acidic paper has been mainly produced, but as the problem of aging of paper has become remarkable, conversion to neutral paper has been actively performed. With the conversion from acid paper to neutral paper, the filler material for paper called filler was changed from talc to calcium carbonate.However, since the calcium tetralucium particles are harder than the talc particles, they are used in the papermaking process. The papermaking net (hereinafter, referred to as a wire) wears quickly, and in particular, a wire made of polyester monofilament has a drawback that its life is shorter than a wire made of polyamide monofilament such as nylon 6. Nylon wire has the advantage that it is relatively hard to wear as described above, but it has the fatal drawback of changing the dimensions of the wire due to moisture during paper making and hindering paper making. Also, improvement of abrasion resistance of a polyester monofilament wire having good dimensional stability has been desired. Conventionally, various proposals have been made to improve the wear resistance of polyester monofilament. For example, a polyester monofilament blended with abrasive particles such as alumina powder, silicon carbide, and zirconia abrasive has a slight effect of improving the abrasion resistance, but the yarn quality is poor due to poor dispersion of the abrasive particles in the polyester. Inferior or abrasion damage to the surface of various rollers or guides that contact monofilament or various fabrics using monofilament, such as monofilament manufacturing process or weaving process of various fabrics using monofilament, and paper machine Had disadvantages. JP-A-63-42976 proposes a method of applying a hard coating such as a polysiloxane coating agent and a cross-linked acrylic coating agent on the surface of a monofilament, but the surface coating easily falls off. There was a problem in terms of durability. JP-A-2-80688 proposes a papermaking woven fabric having improved abrasion resistance using a monofilament in which polyethylene terephthalate contains a specific amount of a thermoplastic polyurethane. The resin decomposes at the temperature of melt spinning with polyethylene terephthalate, making spinning difficult, and has a large industrial problem and is not practical.

SUMMARY OF THE INVENTION An object of the present invention is to provide a polyester monofilament excellent in abrasion resistance and free of the above-mentioned various drawbacks, and a papermaking wire using the monofilament.

SUMMARY OF THE INVENTION The object of the present invention is to provide a polyolefin-based thermoplastic elastomer of 1 to 40.
It can be achieved by a polyester monofilament containing not more than 10% by weight and a papermaking wire using a papermaking wire using the polyester monofilament.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The polyester forming the monofilament of the present invention is mainly composed of a bifunctional component such as an aromatic dicarboxylic acid, or a dialkyl ester thereof, and a glycol component, and is particularly preferably mainly composed of polyethylene terephthalate. . The polyester based on polyethylene terephthalate may be a homopolyester or a copolyester, and as a copolymer component, for example, adipic acid, sebacic acid, phthalic acid,
Dicarboxylic acid components such as naphthalene-2,6-dicarboxylic acid and 5-sodium sulfoisophthalic acid; polyvalent carboxylic acid components such as trimellitic acid and pyromellitic acid;
An oxycarboxylic acid component such as oxyethoxybenzoic acid,
And diol components such as tetramethylene glycol, hexamethylene glycol, diethylene glycol, propylene glycol, neopentyl glycol, polyoxyalkylene glycol, p-xylylene glycol, 1,4-cyclohexanedimethanol, and 5-sodium sulforesorcin. Is also good. The polyester monofilament of the present invention is a continuous yarn consisting of one single yarn mainly composed of the polyester, and has a cross-sectional shape such as a circle, a triangle, a square, a regular polygon, etc. From the viewpoint of, a round cross section is the least hardly worn and is preferable. The diameter of the cross section can be appropriately selected depending on the application, but the range of 0.01 to 3 mm is most often used. Although the required strength of the yarn varies depending on the application, it is preferably 3.0 g / denier or more for a papermaking net. Where the polyester monofilament of the present invention contains, as a polyolefin-based thermoplastic elastomer, for example, mainly a polyolefin such as polypropylene or polyethylene as a hard segment, and mainly an ethylene-propylene-diene-based terpolymer as a soft segment A thermoplastic elastomer comprising a blend can be exemplified. JIS-A hardness of 8 among polyolefin-based thermoplastic elastomers
Those having 5 or less are more preferable. When the JIS-A hardness of the polyolefin-based thermoplastic elastomer is larger than 85, the abrasion resistance of the obtained monofilament tends to be slightly lower, and the variation in the thickness of the monofilament (hereinafter, referred to as wire diameter unevenness) tends to be slightly larger. is there. Note that the thermoplastic elastomer is a polymer that exhibits rubber elasticity at normal temperature and exhibits similar plasticity to thermoplastic at high temperature. The content of the polyolefin-based thermoplastic elastomer in the polyester monofilament is in the range of 1% by weight or more and 40% by weight or less. If the content is less than 1% by weight, the abrasion resistance is not sufficient. On the other hand, if the content is more than 40% by weight, the obtained monofilament has a low elongation and the monofilament wire diameter unevenness increases, which is not preferable. When the content of the polyolefin-based thermoplastic elastomer in the polyester monofilament is 5% by weight or more and 30% by weight or less, abrasion resistance and high elongation characteristics are further improved, and a uniform monofilament with less unevenness in wire diameter is obtained. Is preferable.
A polyester monofilament containing 1% by weight or more and 40% by weight or less of the polyolefin-based thermoplastic elastomer of the present invention can be obtained by the following method. The polyester and the polyolefin-based thermoplastic elastomer can be mixed at any stage from immediately after the completion of the polycondensation of the polyester to the time when the monofilament is spun from the spinneret. Then, a polyolefin-based thermoplastic elastomer is added and kneaded to a polyester in a molten state, formed into chips by a conventional method, dried at a temperature lower than the softening point of the polyolefin-based thermoplastic elastomer, and then melt-pressed or extruded. Melt spinning / stretching using a method such as, or adding a polyolefin-based thermoplastic elastomer chip to dried polyester chips, blending the chips, and kneading and kneading with an extruder-type spinning machine. With a certain amount of po A method of kneading, melt-spinning, and stretching with an extruder spinning machine while supplying ester chips and a polyolefin-based thermoplastic elastomer, or melt-kneading a polyester and a polyolefin-based thermoplastic elastomer in advance with a single- or twin-screw extruder-type kneader. After chipping, drying at a temperature lower than the softening point of the polyolefin-based thermoplastic elastomer, and then melt-spinning and stretching, etc., but at least once at the stage before melt-spinning polyester and polyolefin-based thermoplastic elastomer and Is preferably kneaded.
The temperature at the time of melt spinning can be in the range of the normal polyester melt spinning temperature, that is, the range of the polyester melting temperature or higher and the decomposition temperature or lower, but is preferably 290 ° C. or lower in order to avoid decomposition of the polyolefin-based thermoplastic elastomer. For the same reason, the average contact time with the molten polyester is preferably 15 minutes or less in total, and more preferably 10 minutes or less. The polyester monofilament of the present invention includes various antioxidants, various inert particles such as titanium oxide, various polymers other than the polyolefin-based thermoplastic elastomer, various metal compounds as a catalyst generally used in the production of polyester, and phosphorus compounds used as a coloring prevention. And the like. The polyester monofilament of the present invention has excellent abrasion resistance, and is useful as an industrial material such as a paper net, a filter, and a belt cloth. When used as a papermaking wire, it is preferable because abrasion due to calcium carbonate can be significantly suppressed.

The present invention will be described in more detail with reference to the following examples. The evaluation of wear resistance and unevenness of wire diameter in the examples was performed as follows. A. Abrasion Resistance Evaluation Method A weight of 100 g is attached to the tip of a polyester monofilament, and a calcium carbonate powder manufactured by Sankyo Co., Ltd., which is used as a filler for neutral papermaking on a surface of a ceramic cylinder having a diameter of 60 cm rotating at 1500 rpm. A 0.5% aqueous suspension of Escalon® (registered trademark) # 800 was dropped and contacted, and the time until the monofilament was cut was measured. The abrasion resistance when the monofilament is used as a papermaking net is required to be at least 1.3 times the time required for cutting the monofilament in the present abrasion evaluation than the conventional homopolyester monofilament. You. B. Evaluation method of unevenness of wire diameter Using a laser wire diameter measuring instrument, a monofilament 250
m, the wire diameter was measured at a speed of 50 m / min for 5 minutes, the average of the measured values was defined as the diameter of the filament, and the difference between the maximum value and the minimum value of the measured values was defined as the wire diameter unevenness. In addition, when the monofilament is used as a papermaking net, the difference between the maximum value and the minimum value of the measured value according to the present evaluation method needs to be 20 μm or less from the relationship between the surface uniformity of the paper product and the unevenness of the wire diameter. It is said. Example 1 An intrinsic viscosity of 0.70 (25 in a mixed solvent of phenol and tetrachloroethane 1: 1) dried at 160 ° C. for 8 hours under vacuum.
Polyethylene terephthalate (hereinafter referred to as PE)
T) (88 parts by weight) and a polyolefin-based elastomer (Mitsubishi Yuka Corporation)
And 12 parts by weight of “Thermolan” (registered trademark) 3550, JIS A hardness 55) were mixed in a V-type blender under a nitrogen atmosphere to obtain a blend chip. Next, this blended chip is supplied to an extruder-type melt spinning machine equipped with a nozzle having a hole diameter of 1.5 mm, melt-spun, cooled once, further stretched 5.7 times at 120 ° C., and then relaxed at 0.9 times. By setting, a polyester monofilament having a diameter of 0.22 mm, a wire diameter unevenness of 4 μm, and a strength of 4.1 g / denier was obtained. When the abrasion resistance of this monofilament was evaluated, it took 120 minutes to cut. Comparative Example 1 Except that no polyolefin-based thermoplastic elastomer was used, the procedure was the same as in Example 1, except that the diameter was 0.22 m.
m, P having a wire diameter unevenness of 2 μm and a strength of 4.7 g / denier
A polyester monofilament of ET alone was obtained. When the abrasion resistance of this monofilament was evaluated, it was cut in 15 minutes. Examples 2 and 3 98 parts by weight of PET chips were mixed with a polyolefin-based elastomer (“Thermolan” (registered trademark) 3 manufactured by Mitsubishi Yuka Co., Ltd.).
550, JIS A hardness 55) was changed to 2 parts by weight in the same manner as in Example 1 to obtain a polyester monofilament having a diameter of 0.22 mm, a wire diameter of 3 μm, and a yarn strength of 4.5 g / denier. When the wear resistance of this monofilament was evaluated, it took 30 minutes to cut (Example 2). In addition, 65 parts by weight of PET chips and a polyolefin elastomer (“Thermolan” manufactured by Mitsubishi Yuka Co., Ltd.)
(Registered trademark) 3550, JIS A hardness 55) was changed to 35 parts by weight in the same manner as in Example 1, the diameter was 0.22 mm, the wire diameter unevenness was 11 μm, and the yarn strength was 3.4 g / g.
A denier polyester monofilament was obtained. When the abrasion resistance of this monofilament was evaluated, it took 400 minutes to cut (Example 3). Examples 4 and 5 94 parts by weight of PET chips were mixed with a polyolefin-based elastomer ("Thermolan" (registered trademark) 3 manufactured by Mitsubishi Yuka Co., Ltd.).
550, JIS A hardness 55) was changed to 6 parts by weight in the same manner as in Example 1 to obtain a polyester monofilament having a diameter of 0.22 mm, a wire diameter of 3 μm, and a yarn strength of 4.4 g / denier. When the abrasion resistance of this monofilament was evaluated, it took 70 minutes to cut (Example 4). In addition, 72 parts by weight of a PET chip and a polyolefin-based elastomer (“Thermolan” manufactured by Mitsubishi Yuka Co., Ltd.)
(Registered trademark) 3550, JIS A hardness 55) was changed to 28 parts by weight in the same manner as in Example 1 to obtain a polyester monofilament having a diameter of 0.22 mm, a wire diameter of 8 μm, and a yarn strength of 3.9 g / denier. Was. When the wear resistance of this monofilament was evaluated, 32
It took 0 minutes (Example 5). Examples 6 and 7 A polyolefin-based elastomer was manufactured by Mitsui Petrochemical Industry Co., Ltd. "Milastomer" (registered trademark) 8032N (J
Except for having changed to IS A hardness 80), the same as in Example 1 except that the diameter was 0.22 mm, the wire diameter was 5 μm, and the yarn strength was 4.
1 g / denier polyester monofilament was obtained. When the abrasion resistance of this monofilament was evaluated, it took 115 minutes to cut (Example 6). In addition, a polyolefin-based elastomer is manufactured by Mitsui Petrochemical Industry Co., Ltd., "Milastomer" (registered trademark) 9020N (JIS A).
Except that the hardness was changed to 90), the same as in Example 1 except that the diameter was 0.22 mm, the wire diameter was 12 μm, and the yarn strength was 4.0 g /.
A denier polyester monofilament was obtained. When the abrasion resistance of this monofilament was evaluated, it took 80 minutes to cut (Example 7). Comparative Examples 2 and 3 For comparison, 99.5 parts by weight of a PET chip, and 0.5 parts by weight of a polyolefin-based elastomer (“Thermolan” (registered trademark) 3550, JIS A hardness 55, manufactured by Mitsubishi Yuka Co., Ltd.) were used. A polyester monofilament having a diameter of 0.22 mm, a wire diameter unevenness of 2 μm, and a strength of 4.6 g / denier was obtained in the same manner as in Example 1 except that the parts were changed to parts.
When the wear resistance of this monofilament was evaluated, 17
In minutes (Comparative Example 2). For comparison, the same procedure was performed except that the PET chip was changed to 55 parts by weight and the polyolefin-based elastomer ("Thermolan" (registered trademark) 3550, JIS A hardness 55, manufactured by Mitsubishi Yuka Co., Ltd., 55) was changed to 45 parts by weight. As in Example 1, a diameter of 0.2
A 2 mm polyester monofilament was obtained. When the abrasion resistance of this monofilament was evaluated, it took 580 minutes to cut, but the strength was as low as 2.6 g / denier and the wire diameter unevenness was as large as 30 μm (Comparative Example 3). Table 1 shows the results of the above Examples 1 to 7 and Comparative Examples 1 to 3. From these results, it can be seen that the polyester monofilament of the present invention has excellent abrasion resistance against abrasion by calcium carbonate of a neutral papermaking filler, and has a thread strength and a stable wire diameter required for a papermaking net. Understand.

[Table 1]

The polyester monofilament of the present invention has excellent abrasion resistance against abrasion by calcium carbonate particles and the like for neutral paper, a necessary and sufficient yarn strength and a stable wire diameter. It has excellent characteristics useful as a papermaking wire.

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) D01F 6/62 301-308 D01F 6/84 301-6/86 307 D01F 6/92 301-309 D21F 1/10

Claims (4)

(57) [Claims] 1. A polyester monofilament comprising a polyolefin-based thermoplastic elastomer in an amount of 1 to 40% by weight or less. 2. The polyester monofilament according to claim 1, wherein the polyolefin-based thermoplastic elastomer is mainly composed of a blend of an ethylene-propylene-diene-based terpolymer and a polyolefin. 3. The polyester monofilament according to claim 1, wherein the polyolefin-based thermoplastic elastomer has a JIS-A hardness of 85 or less. 4. A papermaking wire using the polyester monofilament according to claim 1.