JP2009242997A - Polyester monofilament and industrial fabric - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyester monofilament and an industrial fabric using the polyester monofilament which has good flexion fatigue resistance and abrasion resistance as well as high Young's module and dimension stability and is desirable for a constituent material of the industrial fabric. <P>SOLUTION: The polyester monofilament which is composed of a resin composition that contains (C) 0.5-20 weight part of a silicone-based chemical compound against 100 weight part of a polyester mixture composed of (A) 70-99 wt.% by weight of polyethylene naphthalate element and (B) 30-1 wt.% by weight of polyethylene terephthalate. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a polyester monofilament having excellent bending fatigue resistance and wear resistance, high Young's modulus and dimensional stability, and suitable as a constituent material for industrial fabrics, and industrial fabrics using the same. Is.

  In general, fibers represented by monofilaments made of polyester, such as polyethylene terephthalate, have excellent mechanical properties, heat resistance, etc., so that they have conventionally been used for various industrial parts, clothing and industrial fiber materials, various fabrics, etc. Has been used. Among these, monofilaments made of polyethylene naphthalate are superior in tensile strength, high Young's modulus and dimensional stability as compared to general-purpose polyethylene terephthalate monofilaments, and are attracting much attention as industrial fiber materials.

  However, since polyethylene naphthalate monofilament has low yarn elongation and toughness, it has low bending fatigue resistance and wear resistance and is not suitable for continuous use over a long period of time. On the other hand, in recent years, the papermaking speed has been increased, and the temporary stop in the production process accompanying the replacement work of industrial fabrics, for example, the papermaking dryer canvas, has a great influence on the deterioration of work efficiency, so it can be used for a long time. That is, development of polyethylene naphthalate monofilaments that are more excellent in bending fatigue resistance and wear resistance has been demanded.

  Conventionally, various proposals have been made to solve such drawbacks.

  That is, as a technique for improving the bending fatigue resistance, which is a drawback of polyethylene naphthalate, for example, a copolymerized polyethylene naphthalate fiber containing a dimer diol component in a glycol component (for example, see Patent Document 1) is known. However, although the fiber obtained by this technique has improved bending fatigue resistance, it has not been able to exhibit the high Young's modulus required in recent years.

  Further, as a technique for simultaneously improving the Young's modulus and the bending fatigue resistance of polyethylene naphthalate, for example, a polyethylene naphthalate fiber containing a diol unit having a cyclic acetal skeleton (see, for example, Patent Document 2) is known. However, although the fiber obtained by this technique has improved Young's modulus and bending fatigue resistance, it still has a problem that the abrasion resistance necessary for an industrial fabric is still insufficient.

Furthermore, as a technique for simultaneously improving the Young's modulus and surface properties (wear resistance) of polyethylene naphthalate, for example, ethylene-2,6-naphthalate units having an intrinsic viscosity [η] of 0.6 or more are mainly used. Core-sheathed polyester composite fiber formed using polyethylene terephthalate mainly composed of an ethylene terephthalate unit having an intrinsic viscosity [η] of 0.95 or more as a sheath component (for example, patent documents) 3) is known, but the fiber obtained by this technique has improved Young's modulus and surface properties (wear resistance), but has low bending fatigue resistance, and is costly due to compounding. But it was not practical.
Japanese Patent Laid-Open No. 10-17661 JP 2003-193330 A Japanese Patent Laid-Open No. 5-222615

  The present invention has been achieved as a result of investigations aimed at solving the above-described problems in the prior art.

  Therefore, an object of the present invention is to use a polyester monofilament having excellent Young's modulus and dimensional stability as well as excellent bending fatigue resistance and wear resistance, and suitable as a constituent material for industrial fabrics, and the same. It is to provide an industrial fabric.

  As a result of diligent investigations to achieve the above object, the present inventors have added polyethylene terephthalate to polyethylene naphthalate, and further added a silicone compound, whereby bending fatigue resistance and wear resistance are improved. As a result, the present inventors have found that it is possible to improve synergistically and to maintain a high Young's modulus and to secure dimensional stability.

  That is, the present invention provides (C) a silicone compound in an amount of 0.1 to 100 parts by weight of a polyester mixture comprising (A) a polyethylene naphthalate component of 70 to 99% by weight and (B) a polyethylene terephthalate component of 30 to 1% by weight. The polyester monofilament is characterized by comprising a resin composition containing 5 to 20 parts by weight.

In the polyester monofilament of the present invention,
The silanol group content of the silicone compound is 2% or more and 10% or less by weight,
(A) The number of times of MIT bending required for the monofilament to be cut in the bending fatigue property test is 50 times or more. (B) The number of bending wear times at break in the bending wear property test is 1000 times. (C) Young's modulus is 10000 N / mm ² or more and (d) the dry heat shrinkage rate at 180 ° C. is 8.0% or less at the same time, and the intrinsic viscosity of the polyethylene terephthalate is 0.65 to 1.30. It is mentioned as a preferable condition, and by satisfying this condition, more excellent bending fatigue resistance and wear resistance can be obtained.

  The woven fabric of the present invention is characterized by using the above-mentioned polyester monofilament as at least a part of warp and / or weft, and exhibits excellent bending fatigue resistance and wear resistance in industrial fabrics.

  According to the present invention, as described below, it has superior bending fatigue resistance and wear resistance than conventional ones, and has a high Young's modulus and dimensional stability, and is suitable as a constituent material for industrial fabrics. Polyester monofilament and an industrial fabric using the same can be obtained.

  The present invention is described in detail below.

  The polyester monofilament of the present invention comprises three components, (A) polyethylene naphthalate component, (B) polyethylene terephthalate component, and (C) silicone compound as essential components.

  (A) Polyethylene naphthalate (hereinafter abbreviated as PEN) constituting the polyester monofilament in the present invention is that 90 mol% or more of the dicarboxylic acid component is composed of 2,6-naphthalenedicarboxylic acid, and 90 mol% of the glycol component. Those composed of ethylene glycol are preferred.

  PEN is a part of the above 2,6-naphthalenedicarboxylic acid component, for example, terephthalic acid, isophthalic acid, 1,4-cyclohexanedicarboxylic acid, adipic acid, sebacic acid, sulfonic acid metal salt-substituted isophthalic acid, etc. It may be replaced. In addition, a part of the ethylene glycol component is replaced with, for example, propylene glycol, tetramethylene glycol, 1,4-cyclohexanedimethanol, diethylene glycol, neopentyl glycol, 1,4-cyclohexanediol, polyalkylene glycol, and the like. There may be. Furthermore, a small amount of chain branching agents such as pentaerythritol, trimethylolpropane, trimellitic acid, trimesic acid and boric acid can be used in combination.

  PEN includes various types of inorganic particles such as titanium oxide, silicon oxide, calcium carbonate, silicon nitride, clay, talc, kaolin, zirconium acid, carbon black, and other particles such as crosslinked polymer particles and various metal particles. Known sequestering agents, ion exchange agents, anti-coloring agents, light resistance agents, inclusion compounds, antistatic agents, various colorants, various surfactants, and the like may be added.

  The intrinsic viscosity of the PEN used in the present invention is preferably 0.60 or more, and more preferably 0.75 or more. Here, if the intrinsic viscosity is less than 0.60, a high Young's modulus cannot be obtained as an industrial fabric.

  It is important for the polyester monofilament of the present invention to further contain (B) a polyethylene terephthalate component, whereby the bending fatigue resistance is remarkably improved.

  The polyethylene terephthalate (hereinafter abbreviated as PET) constituting the polyester monofilament of the present invention is such that 90 mol% or more of the dicarboxylic acid component is composed of terephthalic acid and 90 mol% or more of the glycol component is composed of ethylene glycol. Is preferred.

  In PET, a part of the above terephthalic acid component was replaced with, for example, 2,6-naphthalenedicarboxylic acid, isophthalic acid, 1,4-cyclohexanedicarboxylic acid, adipic acid, sebacic acid, sulfonic acid metal salt-substituted isophthalic acid, etc. It may be a thing. In addition, a part of the ethylene glycol component is replaced with, for example, propylene glycol, tetramethylene glycol, 1,4-cyclohexanedimethanol, diethylene glycol, neopentyl glycol, 1,4-cyclohexanediol, polyalkylene glycol, and the like. There may be. Furthermore, a small amount of chain branching agents such as pentaerythritol, trimethylolpropane, trimellitic acid, trimesic acid and boric acid can be used in combination.

  PET includes various inorganic particles such as titanium oxide, silicon oxide, calcium carbonate, silicon nitride, clay, talc, kaolin, zirconic acid, carbon black, and other particles such as crosslinked polymer particles and various metal particles. In addition, conventionally known sequestering agents, ion exchange agents, anti-coloring agents, light resistance agents, inclusion compounds, antistatic agents, various coloring agents, various surfactants, and the like may be added.

  The intrinsic viscosity of the PET used in the present invention is usually from 0.65 to 1.30, more preferably from 0.7 to 1.20. Increasing the intrinsic viscosity of PET is beneficial because the strength of the monofilament is further improved. The spinning machine temperature used when melt spinning PEN is 300 ° C or higher. Here, when the intrinsic viscosity of PET is less than 0.65, the melt viscosity of PET is greatly reduced due to the high spinning temperature, and is considerably lower than the melt viscosity of PEN. growing. As a result, the cross-sectional shape of the monofilaments to be spun is not preferable because it causes operability such as eccentricity or frequent occurrence of bumps. If it exceeds 1.30, there will be an unfavorable tendency that drawing breaks frequently occur during spinning, leading to a decrease in operability.

  The component ratio of PEN and PET constituting the polyester monofilament of the present invention is preferably 30 to 1% by weight of PET with respect to 70 to 99% by weight of PEN. If the above range is not satisfied, the high Young's modulus and dimensional stability required for industrial textile monofilaments cannot be obtained.

  It is important that the polyester monofilament of the present invention further contains (C) a silicone compound with respect to the above-mentioned polyester mixture, thereby maintaining a high Young's modulus and synergistic bending fatigue resistance and wear resistance. Improve. This is because the presence of oxygen bond (-O-) in the cytoxane bond that forms the structural skeleton of the silicone compound is excellent in molecular flexibility and the intermolecular interaction is small, while maintaining a high Young's modulus with a small amount of addition. This is because the flexibility can be improved, and since the surface tension is low, abrasion resistance is expressed by bleeding out on the surface of the polyester monofilament.

The silicone compound of the present invention contains an organic group that binds to the Si element, except for the case where it consists only of a structural unit of SiO _2.0 units. The organic group of the silicone compound includes a hydrogen group, a hydroxyl group, A hydrocarbon group, an aromatic hydrocarbon group, etc. are mentioned.

  Specific examples of the hydrocarbon group include a methyl group, an ethyl group, a propyl group, a butyl group, a vinyl group, an allyl group, a methacryl group, and a cyclohexyl group. Examples of the aromatic hydrocarbon group include a phenyl group and a naphthyl group.

  The content of the silicone compound of the present invention needs to be 0.5 to 20 parts by weight with respect to 100 parts by weight of the polyester mixture from the viewpoint of flexural fatigue resistance, wear resistance and Young's modulus, and more preferably 1 0.0 to 10% by weight. When the content is less than 0.5% by weight, bending fatigue resistance and wear resistance cannot be obtained, and when it exceeds 20 parts by weight, not only a high Young's modulus can be obtained as an industrial fabric, but also a spinning process. In this case, the operability such as screw biting failure is hindered.

  Moreover, it is preferable that the silicone type compound of this invention contains the silanol group. This silanol group is a SiOH group. By containing this silanol group, the silanol group is present on the surface of the polyester monofilament, the surface activity is large, and the apparent molecular weight is increased by associating to form a network structure. The increase in the surface activity and the increase in the apparent van der Waals force synergistically increase the fixability on the surface of the polyester monofilament and improve the wear resistance.

  From the viewpoint of wear resistance, the silanol group content is preferably in the range of 2% to 10% by weight, more preferably 3% to 7%, based on the silicone compound.

For the measurement of the amount of silanol groups, the peak area of SiO _2.0 , RSiO _1.5 , R ₂ SiO _1.0 , and R ₃ SiO _0.5 derived from a structure not containing a silanol group in ²⁹ Si-NMR (integral Value) and a structure containing silanol groups derived from Si (OH) ₄ , SiO _0.5 (OH) ₃ , SiO _1.0 (OH) ₂ , SiO _1.5 (OH), RSi (OH) ₃ , RSiO Ratio of peak area (integrated value) of _0.5 (OH) ₂ , RSiO _1.0 (OH), R ₂ Si (OH) ₂ , R ₂ SiO _0.5 (OH), R ₃ Si (OH) From this, it is possible to calculate the amount of silanol groups.

For example, if the ratio of the integral values of RSiO _1.5 and RSiO _1.0 (OH) is 1.5 (RSiO _1.5 ): 1.0 (RSiO _1.0 (OH)), the following formula is obtained. be able to.
Silanol group amount (wt%) = {(ratio of integral value of 17 × RSiO _1.0 (OH)) /
_(RSiO 1.0 (molecular weight × _RSiO 1.0 (OH) ratio of the integral value of the molecular weight × _{RSiO 1.5} ratio + _{RSiO 1.5} of the integrated value of the OH))} × 100 = 17 × 1.0 / (138 × 1.0 + 129 × 1.5) × 100 = 5.13

  The polyester monofilament of the present invention may contain a hydrolysis-resistant additive such as monocarbodiimide in an arbitrary ratio in addition to the polyester and the silicone compound.

  Next, it is preferable that the polyester monofilament of the present invention has a MIT bending number of 50 or more required for cutting, as measured by the following method. If the number of MIT bending is less than the above range, the bending fatigue resistance is lacking, and the operability is hindered, for example, the yarn is broken in the weaving process.

  [Number of MIT flexing times required for cutting] manufactured by Toyo Seiki Co., Ltd .; according to JIS P-8115, load 2.2 cN / dtex, number of folding times 175 times / minute, bending angle 270 according to JIS P-8115 Reciprocal bending until 10 monofilaments are cut for the same sample under the conditions (degrees of left and right about 135 degrees each) and the bending radii of the left and right bending surfaces of the folding frame sandwiching the monofilaments are each 0.38 ± 0.02 mm Measure the number of times to find the average value.

  Further, the polyester monofilament of the present invention needs to have a bending wear number of 1000 or more, preferably 3000 or more, at the time of breaking in a bending wear characteristic test. When the number of bending wear is less than the above range, it is not preferable because it lacks wear resistance and cannot be used for a long time.

[Number of bending wear]
JIS L-1095: It is a value measured by a bending wear characteristic test according to the 1999-9.10.2B method. Specifically, a fixed friction element (hard steel wire (SWP- A)) The polyester monofilament brought into contact with the upper part of two free rollers (distance 100 mm between the two rollers) provided so that the polyester monofilament bends at an angle of 55 ° to the left and right of the friction element. Set the polyester monofilament to one end of the polyester monofilament with a load of 0.196 cN / dtex over another free roller and set the polyester monofilament to the friction element at a speed of 120 reciprocations / minute and a reciprocating stroke of 25 mm. It is the number of times until the polyester monofilament breaks after reciprocating contact.

The polyester monofilament of the present invention preferably has a Young's modulus measured according to JIS L1013 of 10000 N / mm ² or more, more preferably 12000 N / mm ² or more, and further preferably 15000 N / mm ² or more. If the Young's modulus is less than the above range, the Young's modulus is almost the same level as the maximum Young's modulus expressed by the conventional PET monofilament, so that not only the advantage of containing PEN is obtained, but also high Young's as an industrial fabric. It is not preferable because the demand for rate cannot be satisfied.

  The polyester monofilament of the present invention preferably has a dry heat shrinkage at 180 ° C. measured in accordance with JIS L1013 of 8.0% or less, more preferably 5.0% or less. If the dry heat shrinkage at 180 ° C. exceeds the above range, the dimensional stability required for industrial fabrics cannot be obtained.

  The polyester monofilament in the present invention is a single continuous yarn, and the cross-sectional shape perpendicular to the fiber axis direction (hereinafter referred to as cross-sectional shape or cross-section) is round, elliptical, triangular, T, Y, H, + It may have any cross-sectional shape such as various shapes such as 5 leaves, 6 leaves, 7 leaves, 8 leaves, squares, rectangles, rhombuses, dogbones, and saddles.

  As a preferable production example of the polyester monofilament of the present invention, a uniaxial or biaxial extruder hopper contains a necessary amount of dried PEN, PET polyester, a predetermined amount of a silicone compound, or a high concentration of a silicone compound. The polyester masterbatch pellets weighed and melted and kneaded at a temperature above the melting point of the polyester, and then extruded from the spinneret via a metering gear pump provided at the end of the extruder, followed by cooling, stretching, and heat setting. Can be mentioned.

  The polyester monofilament of the present invention thus obtained has both bending fatigue resistance and wear resistance superior to those of the conventional one, and has a high Young's modulus and dimensional stability. It is useful as a material.

  Therefore, the industrial fabric comprising the polyester monofilament of the present invention is superior in bending fatigue resistance and wear resistance, and thus can be used for a longer period of time than before, and has high industrial utility value. .

  The industrial fabric in the present invention refers to a fabric used in various industrial applications in which the polyester monofilament of the present invention is used as at least a part of the warp and / or weft of the fabric. Woven fabrics), fabrics mounted on paper machines such as paper dryers, canvases, etc., net conveyor fabrics for thermal bonding nonwoven fabric thermal bonding processes, belt fabrics for transport in heat treatment furnaces, and various filter fabrics.

  Here, the papermaking wire is a woven fabric used in the paper winding process as various woven fabrics such as plain weave, double weave, and triple weave, and is used as a long mesh or a round mesh. The paper dryer canvas is a paper machine as various fabrics such as plain weave, double weave, and triple weave (including spiral fabrics in which wefts and wefts that follow each other are woven by spiral monofilaments). It is a fabric used for drying paper in a dryer. Furthermore, the belt woven fabric for the thermal bonding process of the nonwoven fabric is a woven fabric for allowing the nonwoven fabric to pass through the furnace in order to fuse the thermal adhesive fibers such as low melting point polyethylene constituting the nonwoven fabric. Heavy woven fabrics. Moreover, the belt fabric for conveyance in a heat treatment furnace is a fabric which conveys a semi-finished product in a high temperature zone for drying, thermosetting, sterilization, cooking, etc. of various semi-finished products. Furthermore, various filters are fabrics that filter high-temperature liquids, gases, powders, and the like.

  Hereinafter, the polyester monofilament of the present invention will be described in more detail based on examples.

  In the examples, the number of MIT flexing times, the number of flexing wears at break, the Young's modulus, and the dry heat shrinkage at 180 ° C. are measured according to the above methods, and the intrinsic viscosity and the amount of silanol groups are measured according to the following methods. It was.

<Intrinsic viscosity of PET>
It calculated | required from the viscosity measured at 25 degreeC in the orthochlorophenol solution.

<Amount of silanol groups (% by weight)>
The reaction time at the time of condensing the silicone compound was adjusted, and the obtained silicone compound was measured by ²⁹ Si-NMR using CDCl ₃ as a solvent and TMS (tetramethylsilane) as a standard substance at a total number of 256 times. and, _SiO 2.0 structures derived containing no silanol _{group, RSiO 1.5, R 2 SiO 1.0} , the peak of the R _{3 SiO 0.5} area from structures containing (integrated value) with the silanol groups Si (OH) ₄ , SiO _0.5 (OH) ₃ , SiO _1.0 (OH) ₂ , SiO _1.5 (OH), RSi (OH) ₃ , RSiO _0.5 (OH) ₂ , RSiO _{1. From} the ratio of peak areas (integrated values) of ₀ (OH), R ₂ Si (OH) ₂ , R ₂ SiO _0.5 (OH), and R ₃ Si (OH), RSiO _1.0 (OH) and RSi The amount of silanol groups was calculated from the ratio of each integrated value of O _1.5 .

[Example 1]
Using a PET resin (T701 manufactured by Toray Industries, Inc.), a blending ratio of PET resin: silicone compound (silanol group amount 5.2%) = 60 wt%: 40 wt%, kneading temperature: 300 ° C., L / D: 30 Then, kneading was performed using a biaxial extruder under the condition of screw rotation speed: 300 rpm, to obtain a resin composition in which a silicone compound was mixed in PET.

  Extruder type PEN resin (PN-640 manufactured by Toyobo Co., Ltd.), PET resin and the above resin composition so that the final composition ratio is PEN resin: PET resin: silicone compound = 92: 8: 3 Using a spinning machine, melt-kneaded at a spinning temperature of 320 ° C., extruding the molten polymer from the spinneret (die hole diameter: 1.5 mm-15H (hole)), and immediately cooled and solidified in a hot water bath. I got a thread.

  Subsequently, the undrawn yarn was drawn and heat-set to a total of 7.0 times in accordance with a conventional method to obtain a polyester monofilament having a diameter of 0.40 mm and a circular cross section. Table 1 shows the MIT flex number, flex wear rate, Young's modulus, and dry heat shrinkage at 180 ° C. of the obtained polyester monofilament.

[Examples 2 and 3]
A polyester monofilament having a circular cross-sectional shape of 0.40 mm in diameter in the same manner as in Example 1 except that the final composition ratio of the used PEN resin, PET resin and silicone compound was changed as shown in Table 1. Got.

[Comparative Examples 1-4]
A polyester monofilament having a circular cross-sectional shape of 0.40 mm in diameter in the same manner as in Example 1 except that the final composition ratio of the used PEN resin, PET resin and silicone compound was changed as shown in Table 1. Got.

  The physical property evaluation results of these obtained monofilaments are also shown in Table 1.

  As is apparent from Table 1, the polyester monofilament in the present invention, that is, a polyester monofilament composed of three components (A) polyethylene naphthalate, (B) polyethylene terephthalate and (C) silicone compound as essential components (Examples 1 to It can be seen that 3) has excellent bending fatigue resistance and wear resistance, and also has high Young's modulus and dimensional stability required as a constituent material for industrial fabrics.

  On the other hand, polyester monofilaments outside the present invention, that is, polyester monofilaments lacking at least one of the three components (A) polyethylene naphthalate, (B) polyethylene terephthalate and (C) silicone compound (Comparative Example 1) To 2), and polyester monofilaments (Comparative Examples 3 to 4) in which the weight ratio of the polyester and the content of the silicone compound deviate from those of the present invention (Comparative Examples 3 to 4) are inferior in bending fatigue resistance and wear resistance, or industrial It can be seen that it does not have the Young's modulus and the dimensional stability required for textiles.

  The polyester monofilament of the present invention has a bending fatigue resistance and wear resistance superior to those of conventional ones, and has a high Young's modulus and dimensional stability, and is therefore suitable as a constituent material for industrial fabrics. is there.

Claims (5)

0.5 to 20 parts by weight of (C) silicone compound is contained with respect to 100 parts by weight of the polyester mixture comprising (A) polyethylene naphthalate component 70 to 99% by weight and (B) polyethylene terephthalate component 30 to 1% by weight. A polyester monofilament comprising the resin composition prepared. The polyester monofilament according to claim 1, wherein the amount of silanol groups of the silicone compound is 2% or more and 10% or less by weight. The polyester monofilament according to claim 1 or 2, wherein the following requirements (a) to (d) are satisfied at the same time.
(A) The number of MIT bends required for cutting in the bending fatigue characteristic test is 50 times or more,
(B) The number of times of bending wear at break in the bending wear characteristic test is 1000 times or more,
(C) Young's modulus is 10,000 N / mm ² or more,
(D) The dry heat shrinkage at 180 ° C. is 8.0% or less. The polyester monofilament according to any one of claims 1 to 3, wherein the polyethylene terephthalate has an intrinsic viscosity of 0.65 to 1.30. An industrial fabric, wherein the polyester monofilament according to any one of claims 1 to 4 is used for at least part of warp and / or weft.