JP2007217832A - Polyester fiber for industrial material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a polyester fiber that has a higher strength than that of a conventional product and is suitably useful in various uses as a rubber reinforcing fiber for a tire cord, a belt, a hose, etc., an industrial material for a seat belt, a fiber for fishing net, etc., due to excellent light resistance. <P>SOLUTION: The polyester fiber for an industrial material contains 0.5-150 ppm calculated as a titanium atom of a titanium compound as a polycondensation catalyst and has (1) a cooling crystallization peak temperature Tc2 measured by a differential scanning calorimeter (DSC) of ≥185°C and a temperature difference (ΔT) between Tc2 and a heating crystallization peak temperature Tc1 of ≥40°C, (2) an intrinsic viscosity of ≥0.75 and (3) a strength of ≥6.0 cN/dtex. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a polyester fiber for industrial materials. More specifically, since it has high strength and excellent light resistance, it can be suitably used for various applications as industrial materials such as rubber reinforcing fibers such as tire cords, belts and hoses, seat belts, and fishing net fibers. It relates to polyester fibers.

  Polyester represented by polyethylene terephthalate (hereinafter referred to as PET) is excellent in mechanical strength, chemical resistance, etc., so it is widely used for fiber, film or resin applications. It is also widely used for industrial materials as a reinforcing material for rubber products such as tire cords, belts and hoses.

  Polyester fibers for industrial materials are required to contain no foreign matter that causes a decrease in strength, and that there is no increase in filtration pressure or contamination of the base during yarn production. It is known that it is a foreign substance (antimony catalyst residue) insoluble in the polymer due to the antimony compound. Since this antimony catalyst residue tends to be a relatively large particulate matter, it has unfavorable characteristics such as increased filtration pressure due to filter clogging during molding and thread breakage during spinning. This is one of the causes of lowering. As a method for obtaining a high-strength yarn by reducing foreign matter caused by an antimony compound, a germanium compound is used instead of the antimony compound (Patent Document 1), or a polyester using a combination of a germanium compound and an antimony compound (patent) Although document 2) has been proposed, germanium compounds are very expensive and difficult to use for general purposes. In addition, as a polycondensation catalyst other than antimony compounds and germanium compounds, a method using an aluminum compound (Patent Document 3), a titanium compound such as a tetraalkoxy titanate, a titanium complex composed of a titanium compound and a phosphorus compound, or a specific titanium complex The methods used (Patent Documents 4 and 5) have also been proposed. The application of these titanium compounds will surely reduce the generation of catalyst-derived foreign matter as in the case of applying antimony compounds, and can improve the strength and toughness of the fiber to some extent, but the titanium compounds as conventionally known The simple application of is not sufficient for properties such as strength and light resistance required for industrial materials, and further improvements were required in use.

In order to obtain polyester fibers for industrial materials having the above-mentioned properties, the present invention has been intensively studied not only in the spinning and drawing processes, but also in the polycondensation catalyst type and polymer molecular weight used in the production of the polyester, and also in the thermal crystallization characteristics. . As a result, the inventors have found that there is a close relationship between the molecular weight and the thermal crystallization characteristics of the polyester fiber for industrial materials including the polymerization catalyst species and the catalyst amount, and the present invention has been achieved.
JP-A-2-182914 (Claims) Japanese Patent Laid-Open No. 3-161509 (Claims) JP 2002-194618 A (Claims) JP 2001-524536 A (Claims) JP 2004-149938 A (Claims)

  The object of the present invention is to solve the above-mentioned conventional problems, and is higher in strength and superior in light resistance than conventional products. Therefore, rubber reinforcing fibers such as tire cords, belts and hoses, seat belts, and fishing nets are used. It is providing the polyester fiber which can be utilized suitably for various uses, such as a fiber, for industrial materials.

  In order to solve the above problems, the polyester fiber of the present invention mainly has the following configuration. That is, a polyester containing 0.5 to 150 ppm of a titanium compound as a polycondensation catalyst, (1) a cooling crystallization peak temperature Tc2 measured with a differential scanning calorimeter (DSC) is 185 ° C. or higher, Further, the temperature difference (ΔT) from the temperature rising crystallization peak temperature Tc1 is 40 ° C. or higher, (2) the intrinsic viscosity is 0.75 or higher, and (3) the strength is 6.0 cN / dtex or higher. This can be achieved by using polyester fibers for industrial materials.

  The polyester fiber of the present invention solves the conventional problems, has higher strength than conventional products, and is excellent in light resistance. Therefore, it is possible to provide a polyester fiber that can be suitably used for various uses for industrial materials.

  The polyester of the present invention is composed of a diol mainly composed of terephthalic acid which is an aromatic dicarboxylic acid and ethylene glycol. In addition to diethylene glycol, the polyester of the present invention includes dicarboxylic acids such as adipic acid, isophthalic acid, sebacic acid, phthalic acid, naphthalenedicarboxylic acid, 4,4′-diphenyldicarboxylic acid, cyclohexanedicarboxylic acid and the like as copolymerization components in addition to diethylene glycol. Ester-forming derivatives, dioxy compounds such as polyethylene glycol, hexamethylene glycol, neopentyl glycol, polypropylene glycol and cyclohexanedimethanol, oxycarboxylic acids such as p- (β-oxyethoxy) benzoic acid and ester-forming derivatives thereof It may be copolymerized.

The polycondensation catalyst of the present invention is a polymer synthesized from a dicarboxylic acid or an ester-forming derivative thereof and a diol or an ester-forming derivative thereof, or all or part of the following reactions (1) to (3): It refers to a compound that contributes substantially to the acceleration of the elementary reaction.
(1) Esterification reaction which is reaction of dicarboxylic acid component and diol component (2) Transesterification reaction which is reaction of dicarboxylic acid or its ester-forming derivative and diol component (3) The ester reaction is substantially completed The polycondensation reaction in which the obtained low polymer is highly polymerized by a dediol reaction is not limited, but a titanium complex is preferably used as the polymerization catalyst in the present invention. A titanium complex is a titanium compound containing a chelating agent having the ability to coordinate to a titanium atom, and there is no particular limitation. Especially when a titanium chelate compound of hydroxycarboxylic acid is used, the color tone of the resulting polymer becomes good. Less foreign matter generation is preferable. In particular, a hydroxy polyvalent carboxylic acid or a titanium chelate of a nitrogen-containing polyvalent carboxylic acid is preferable.

  Examples of chelating agents that form such titanium complexes include hydroxycarboxylic acid compounds such as lactic acid, salicylic acid, and benzylic acid, hydroxypolycarboxylic acids such as malic acid, tartaric acid, and citric acid, ethylenediaminetetraacetic acid, and nitrilotripropionic acid. , Carboxyiminodiacetic acid, carboxymethyliminodipropionic acid, diethylenetriaminopentaacetic acid, triethylenetetraminohexaacetic acid, iminodiacetic acid, iminodipropionic acid, hydroxyethyliminodiacetic acid, hydroxyethyliminodipropionic acid, methoxyethyliminodi The functional group which consists of nitrogen-containing polyhydric carboxylic acids, such as an acetic acid, is mentioned.

  The titanium compound as a catalyst in the present invention needs to be added so as to be 0.5 to 150 ppm in terms of titanium atom with respect to the obtained polyester. When the addition amount is 0.5 ppm or more, the polymerization reactivity is sufficient, and a polymer having a practical intrinsic viscosity can be obtained with good productivity. Addition of an amount not exceeding 150 ppm does not produce coarse particles due to titanium, so that spinnability is good, and a fiber having high strength and good characteristics can be obtained. More preferably, it is 1-100 ppm, More preferably, it is 3-50 ppm.

  The titanium compound as the catalyst of the present invention may be added to the polyester reaction system as it is, but the compound is mixed with a solvent containing a diol component that forms a polyester such as ethylene glycol in advance to form a solution or slurry. Accordingly, it is preferable to add to the reaction system after removing low-boiling components such as alcohol used at the time of synthesis of the compound, since the generation of foreign matters in the polymer is further suppressed. As the esterification reaction catalyst, there are a method of adding the catalyst immediately after the addition of the raw material and a method of adding the catalyst accompanied with the raw material. Further, when added as a polycondensation reaction catalyst, it may be substantially before the start of the polycondensation reaction, and added before the esterification reaction or after the completion of the reaction, before the start of the polycondensation reaction catalyst. Also good.

  The polyester fiber of the present invention has a cooling crystallization peak temperature Tc2 measured by a differential scanning calorimeter (hereinafter referred to as DSC) of 185 ° C. or more and a temperature difference (ΔT) from the temperature rising crystallization peak temperature Tc1. Must be 40 ° C. or higher. By satisfying these two requirements at the same time, a polyester fiber having high strength and excellent light resistance can be obtained. The cooling crystallization peak temperature Tc2 is 190 ° C. or higher, and the temperature rise crystallization peak temperature Tc1 is More preferably, the temperature difference (ΔT) is 45 ° C. or more.

  In addition, it is difficult to satisfy the strength and light resistance only by satisfying one of the above two requirements. For example, even if the cooling crystallization peak temperature Tc2 is 185 ° C. or higher, the temperature rising crystallization peak Even if the temperature difference (ΔT) from the temperature Tc1 is less than 40 ° C., or the temperature difference (ΔT) from the temperature rising crystallization peak temperature Tc1 is 40 ° C. or more, the cooling crystallization peak temperature Tc2 is less than 185 ° C. In such a case, the strength is lowered or the light resistance is inferior.

  In order to obtain a polyester fiber having a cooling crystallization peak temperature Tc2 measured by DSC in the present invention of 185 ° C. or higher and a temperature difference (ΔT) from the temperature rising crystallization peak temperature Tc1 of 40 ° C. or higher, In the polycondensation, (A) alkali metal and / or alkaline earth metal compound and phosphorus compound are added to ethylene glycol in advance, and a treatment solution obtained by superheating the mixture is added to the reaction system. (B) talc, kaolin Examples thereof include a method in which inorganic fine particles such as silica are added to the reaction system, or (C) a plasticizer such as montanic acid wax is added to the reaction system in a small amount, and a polymer obtained by polymerization is spun and stretched.

  The alkali metal compound and alkaline earth metal compound used in the above (A) include lithium, sodium, potassium, rubidium and the like as the alkali metal, and magnesium, calcium and strontium as the alkaline earth metal. In particular, an alkali metal compound is preferable, and sodium or potassium is particularly preferably used. Here, acetate, benzoate, formate, hydrochloride, oxalate, nitrate, carbonate, etc. are used as the metal compound, but acetate and benzoate are used because of their solubility in ethylene glycol. Particularly preferably used. These metal compounds may be hydrates or anhydrides. The phosphorus compound may be any of phosphoric acid, phosphorous acid, phosphonic acid, phosphinic acid, phosphine oxide, and specifically, for example, phosphoric acid, trimethyl phosphate, triethyl phosphate, etc. Phosphoric acid systems, phosphorous acid systems such as phosphorous acid and trimethyl phosphite, and phosphonic acid systems such as methylphosphonic acid, ethylphosphonic acid, and phenylphosphonic acid are used. And phosphonic acid systems such as dimethylphenylphosphonic acid and dimethylphosphonic acid are particularly preferably used.

  In addition, although the alkali metal compound and the alkali metal compound are included in the treatment liquid in the above (A), by adding at 5 to 1000 ppm as each metal atom in the polyester, The temperature difference (ΔT) between the cooling crystallization peak temperature Tc2 measured with a differential scanning calorimeter (hereinafter referred to as DSC) and the temperature rising crystallization peak temperature Tc1 of the polyester fiber can be easily set. It is preferable from the above, and it is more preferable to contain 5 to 500 ppm from the viewpoint of the strength and light resistance of the polyester fiber.

  As for (B), inorganic particles such as kaolin and silica, which have been refined by pulverization and classification, are preferably used. The average particle diameter of these particles is 0.001 to 2.5 μm. Further, by using a material in the range of 0.02 to 1.5 μm, there are few coarse foreign matters, and more preferable from the viewpoint of strength characteristics and light resistance of the polyester fiber.

  In addition, the above (C) can obtain the same effect by adding 0.005 to 1% by weight of an organic compound such as montanic acid wax acid, neutral or partially neutralized montan wax acid metal salt, and the like. Are preferably used.

  The cooling crystallization peak temperature Tc2 and the temperature rising crystallization peak temperature can be easily controlled, and the method according to (A) or (B) is preferable from the characteristics of the obtained polyester fiber, and (A) is particularly preferable.

  In the present invention, the above-described phosphorus compounds and other phosphorus compounds may be further used in order to improve the color tone of the polyester or to improve the heat resistance of the obtained polyester.

  The intrinsic viscosity (hereinafter referred to as IV) of the polyester fiber of the present invention needs to be 0.75 or more, preferably 0.80 or more. When the IV is less than 0.75, the strength and toughness are inferior for industrial materials. Further, IV is preferably 1.30 or less from the viewpoint of stability during yarn production.

  The polyester fiber of the present invention preferably has a small number of coarse foreign substances from the viewpoint of fiber characteristics. Specifically, the average number of coarse foreign substances of 5 μm or more is 10 or less per 10 mg of polyester fibers as an average value of 10 observation samples. This is preferable because polyester fibers having high strength and toughness can be obtained. More preferably, it is 5 or less per 10 mg of polyester fiber, more preferably 2 or less.

Furthermore, the polyester fiber of the present invention has a diethylene glycol amount (hereinafter referred to as DEG amount).
However, it is preferably 1.3 wt% or less from the viewpoint of strength and light resistance, and more preferably 1.25 wt% or less. Further, the carboxyl group terminal amount (hereinafter referred to as COOH amount) is preferably 40 eq / ton or less from the viewpoint of light resistance, and more preferably 35 eq / ton or less.

  In addition to conventionally known pigments such as titanium oxide and carbon black, additives such as conventionally known anti-coloring agents, stabilizers and antioxidants may be included.

  Although the polyester fiber for industrial materials of this invention is obtained by the following method, for example, the example of PET is described as a specific example.

  First, a polyester polymer is usually produced by any one of the following processes. (1) A process in which terephthalic acid and ethylene glycol are used as raw materials, a low polymer is obtained by direct esterification reaction, and a high molecular weight polymer is obtained by subsequent polycondensation reaction, and (2) dimethyl terephthalate and ethylene glycol are used as raw materials. The low polymer is obtained by the transesterification reaction, and the high molecular weight polymer is obtained by the subsequent polycondensation reaction. Although the esterification reaction proceeds even without a catalyst, the titanium compound of the present invention may be added as a catalyst.

  The polyester polymer of the present invention is a polymerization catalyst formed in the low polymer obtained in any stage of the series of reactions (1) or (2) described above, preferably in the first half of the series of reactions (1) or (2). In addition to adding a titanium compound, a polycondensation reaction is performed by adding a heat treatment liquid and / or fine particles to obtain a high molecular weight PET. In polycondensation, the charge amount, polymerization temperature, and polymerization time are appropriately selected to obtain a PET chip having an intrinsic viscosity of 0.65 or more.

  Moreover, although said reaction is implemented by forms, such as a batch type, a semibatch type, or a continuous type, the manufacturing method of this invention can be applied to any of those forms.

  As a method for producing the polyester fiber for industrial materials of the present invention using the above polyester polymer, a conventionally known method can be employed. For example, the chip is solid-phase polymerized by a conventional method to have an intrinsic viscosity of 0. .90 or more, this high molecular weight polyester polymer was melted with an extruder-type spinning machine, filtered with a spinning pack, spun through the pores of the die, cooled and solidified with cold air, and then an oil agent was applied. After stretching by 3.5 times, a method of heat treatment of tension or relaxation can be adopted. The obtained polyester fiber for industrial materials of the present invention has excellent physical properties such as strength of 6.0 cN / dtex or more, elongation of 8 to 30%, and dry heat shrinkage at 150 ° C. of 2 to 15%. is there.

  Moreover, since the polyester fiber for industrial materials of the present invention has the excellent characteristics as described above, it is mainly used as a rubber reinforcing fiber for tire cords, belts, hoses, etc., and for seat belts and fishing nets. It can be applied to various uses as an industrial material.

Hereinafter, the present invention will be described in more detail with reference to examples. In addition, the characteristic value in an Example was measured by the method described below.
(1) Cooling crystallization peak temperature (Tc2) and temperature difference (ΔTc) from the temperature rising crystallization peak temperature Tc1
It calculated | required by the following measuring method using Perkin-Elmer DSC7 type | mold. 10 mg of polyester fiber was sampled, and the sample was heated to 300 ° C. at a rate of 16 ° C./min, held for 10 minutes, and then cooled at a rate of 16 ° C./min. About the crystallization peak temperature that appears during the temperature rise and the crystallization peak temperature that appears during the temperature drop, using the Perkin Elmer data processing system, the crystallization peak temperature (Tc1) that appears during the temperature rise, the cooling crystallization peak The temperature (Tc2) was determined, and the temperature difference ΔTc was determined from the values of Tc2 and Tc1.
(2) Intrinsic viscosity IV
Measurement was performed at 25 ° C. using orthochlorophenol as a solvent.
(3) Titanium element and other metal contents It calculated | required with the fluorescent-X-ray elemental-analysis apparatus (Horiba Seisakusho make, MESA-500W type) or the ICP emission analyzer (Seiko Instruments make, SPS1700).
(4) High elongation Using a Tensilon tensile tester manufactured by Toyo Boardwin, the SS curve was obtained at a sample length of 25 cm and a tensile speed of 30 cm / min, and the high elongation was calculated.
(5) Dry heat shrinkage rate The length measured by taking a sample in a skein shape and leaving it in a temperature-controlled room at 20 ° C. and 65% RH for 24 hours or more and then applying a load corresponding to 0.1 g / dtex of the sample. after 30 minutes in 0.99 ° C. in an oven in sample no tension state of l _0, removed from the oven and allowed to stand for 4 hours at the temperature control chamber, the following equation from the length l ₁ measured again over the load Calculated by

Dry heat shrinkage = {(l ₀ −l ₁ ) / l ₀ } × 100 (%)
(6) DEG
The sample was subjected to alkali decomposition and then quantified using gas chromatography.
(7) COOH
0.5 g of a sample was dissolved in 10 ml of o-cresol, cooled after being completely dissolved, 3 ml of chloroform was added, and potentiometric titration was performed with a methanol solution of NaOH.
(8) Number of coarse particles After a small amount of polyester has been quantified, it is sandwiched between two cover glasses, melted at 290 ° C., pressed to a uniform film thickness, and then rapidly cooled. The sample thus obtained is observed using an optical microscope. The number of coarse particles of 5 μm or more existing in a certain area was counted, and the number of coarse particles per 10 mg of polymer was calculated from the weight of the sample and the total area after pressing. In addition, the average value of 10 observation samples was shown.
(9) Light resistance After irradiating the original yarn for 200 hours at a black panel temperature of 83 ° C. with a sunshine weather meter, the strength retention is obtained from the ratio of strength before and after the treatment, and the level of conventional yarn is x, A 4% increase is indicated by ○, and 4% or more is indicated by ◎.

Reference example 1
The method for synthesizing the catalyst is described below.
Catalyst A. Citric acid chelate titanium compound synthesis method Citric acid monohydrate (532 g, 2.52 mol) was dissolved in warm water (371 g) in a 3 L flask equipped with a stirrer, a condenser and a thermometer. To this stirred solution was slowly added titanium tetraisopropoxide (288 g, 1.00 mol) from the addition funnel. The mixture was heated to reflux for 1 hour to produce a cloudy solution from which the isopropanol / water mixture was distilled under vacuum. The product was cooled to a temperature below 70 ° C., and a 32 wt / wt% aqueous solution of NaOH (380 g, 3.04 mol) was slowly added via a dropping funnel to the stirred solution. The resulting product was filtered and then mixed with ethylene glycol (504 g, 80 mol) and heated under vacuum to remove isopropanol / water and a slightly cloudy light yellow product (Ti content 3 .85% by weight).

Catalyst B. Synthesis method of citric acid chelate titanium compound (phenyl phosphonic acid mixed) Citric acid monohydrate (532 g, 2.52 mol) in warm water (371 g) in a 3 L flask equipped with stirrer, condenser and thermometer Was dissolved. To this stirred solution was slowly added titanium tetraisopropoxide (288 g, 1.00 mol) from the addition funnel. The mixture was heated to reflux for 1 hour to produce a cloudy solution from which the isopropanol / water mixture was distilled under vacuum. The product was cooled to a temperature below 70 ° C., and a 32 wt / wt% aqueous solution of NaOH (380 g, 3.04 mol) was slowly added via a dropping funnel to the stirred solution. The resulting product was filtered and then mixed with ethylene glycol (504 g, 80 mol) and heated under vacuum to remove isopropanol / water and a slightly cloudy light yellow product (Ti content 3 .85% by weight). To this mixed solution, phenylphosphonic acid (158 g, 1.00 mol) was added to obtain a titanium compound containing a phosphorus compound (P content: 2.49 wt%).

Catalyst C. Method for synthesizing citric acid chelate titanium compound (mixed of phenylphosphonic acid and phosphoric acid) In a 3 L flask equipped with a stirrer, a condenser and a thermometer, warm water (371 g) was mixed with citric acid / monohydrate (532 g, 2. 52 mol) was dissolved. To this stirred solution was slowly added titanium tetraisopropoxide (288 g, 1.00 mol) from the addition funnel. The mixture was heated to reflux for 1 hour to produce a cloudy solution from which the isopropanol / water mixture was distilled under vacuum. The product was cooled to a temperature below 70 ° C., and a 32 wt / wt% aqueous solution of NaOH (380 g, 3.04 mol) was slowly added via a dropping funnel to the stirred solution. The resulting product was filtered and then mixed with ethylene glycol (504 g, 80 mol) and heated under vacuum to remove isopropanol / water and a slightly cloudy light yellow product (Ti content 3 .85% by weight). To this mixed solution, phenylphosphonic acid (158 g, 1.00 mol) and an aqueous 85 wt / wt% phosphoric acid solution (39.9 g, 0.35 mol) were added to obtain a titanium compound containing a phosphorus compound. Obtained (P content 3.36% by weight).

Catalyst D. Method for synthesizing lactic acid chelate titanium compound Titanium tetraisopropoxide (285 g, 1.00 mol) stirred in a 1 L flask equipped with a stirrer, a condenser and a thermometer was added from an addition funnel to ethylene glycol (218 g, 3 .51 mol) was added. The rate of addition was adjusted so that the heat of reaction warmed the flask contents to about 50 ° C. The reaction mixture was stirred for 15 minutes and an 85 wt / wt% aqueous solution of ammonium lactate (252 g, 2.00 mol) was added to the reaction flask to give a clear pale yellow product (Ti content 6.54 wt. %).

Catalyst E. Synthesis Method of Lactic Acid Chelate Titanium Compound (Phenylphosphonic Acid Mixture) From a dropping funnel to titanium tetraisopropoxide (285 g, 1.00 mol) stirred in a 2 L flask equipped with a stirrer, condenser and thermometer Ethylene glycol (218 g, 3.51 mol) was added. The rate of addition was adjusted so that the heat of reaction warmed the flask contents to about 50 ° C. The reaction mixture was stirred for 15 minutes and an 85 wt / wt% aqueous solution of ammonium lactate (252 g, 2.00 mol) was added to the reaction flask to give a clear pale yellow product (Ti content 6.54 wt. %). By adding phenylphosphonic acid (158 g, 1.00 mol) to this mixed solution, a titanium compound containing a phosphorus compound was obtained (P content 4.23 wt%).

Catalyst F. Synthesis method of lactate chelate titanium compound (phenylphosphonic acid, phosphoric acid mixed) To titanium tetraisopropoxide (285 g, 1.00 mol) stirred in a 2 L flask equipped with a stirrer, condenser and thermometer Ethylene glycol (218 g, 3.51 mol) was added from the dropping funnel. The rate of addition was adjusted so that the heat of reaction warmed the flask contents to about 50 ° C. The reaction mixture was stirred for 15 minutes and an 85 wt / wt% aqueous solution of ammonium lactate (252 g, 2.00 mol) was added to the reaction flask to give a clear pale yellow product (Ti content 6.54 wt. %). To this mixed solution, phenylphosphonic acid (158 g, 1.00 mol) and an aqueous 85 wt / wt% phosphoric acid solution (39.9 g, 0.35 mol) were added to obtain a titanium compound containing a phosphorus compound. Obtained (P content 5.71% by weight).

Reference example 2
A method for adjusting the heat treatment liquids a to d will be described below.
Treatment liquid a
Sodium acetate (anhydride) (41.2 g), 85% aqueous phosphoric acid solution (5.8 g), and ethylene glycol (1600 g) were placed in a 3 L flask equipped with a stirrer, a condenser and a thermometer at 150 ° C. And stirred for 2 hours to obtain a heat treatment liquid.
Treatment liquid b
Sodium acetate (anhydride) (41.2 g), dimethylphenylphosphonic acid (18.6 g), and ethylene glycol (1600 g) were placed in a 3 L flask equipped with a stirrer, a condenser and a thermometer at 150 ° C. The mixture was heated and stirred for 2 hours to obtain a heat treatment liquid.
Treatment liquid c
Potassium acetate (anhydride) (28.9 g), dimethylphenylphosphonic acid (18.6 g), and ethylene glycol (1600 g) were placed in a 3 L flask equipped with a stirrer, a condenser and a thermometer at 150 ° C. The mixture was heated and stirred for 2 hours to obtain a heat treatment liquid.
Treatment liquid d
In a 3 L flask equipped with stirrer, condenser and thermometer, magnesium acetate (tetrahydrate) (107.3 g), dimethylphenylphosphonic acid (18.6 g), and ethylene glycol (1600 g) were placed. The mixture was heated and stirred at 0 ° C. for 2 hours to obtain a heat treatment liquid.

Example 1
A slurry of 100 kg of high-purity terephthalic acid (manufactured by Mitsui Chemicals) and 45 kg of ethylene glycol (manufactured by Nippon Shokubai Co., Ltd.) is charged with about 123 kg of bis (hydroxyethyl) terephthalate in advance, at a temperature of 250 ° C. and a pressure of 1.2 × 10 ⁵ Pa. It was sequentially supplied to the held esterification reaction tank over 4 hours, and after completion of the supply, the esterification reaction was further performed over 1 hour, and 123 kg of this esterification reaction product was transferred to the polycondensation tank. Subsequently, in the polycondensation reaction tank to which the esterification reaction product has been transferred, a 2 wt% ethylene glycol solution of catalyst A (citrate chelate titanium compound) (10 ppm in terms of titanium atom relative to the polymer), heat treatment liquid a (50 ppm as sodium metal atom to the polymer) was added. Thereafter, while stirring the low polymer at 30 rpm, the reaction system was gradually heated from 250 ° C. to 290 ° C. and the pressure was lowered to 40 Pa. The time to reach the final temperature and final pressure was both 60 minutes. When the predetermined stirring torque was reached, the reaction system was purged with nitrogen to return to normal pressure, and the polycondensation reaction was stopped. The reaction polymer was discharged into cold water in a strand form and immediately cut to obtain polymer pellets. The time from the start of decompression to the arrival of the predetermined stirring torque was 2 hours and 45 minutes.

  The intrinsic viscosity of the obtained polymer was 0.72. Moreover, it confirmed that the titanium atom content derived from the titanium catalyst in a polymer was 10 ppm, and a sodium atom was 50 ppm.

  After drying this polyester, solid phase polymerization was performed at 210 ° C. to obtain chips having an intrinsic viscosity of 1.16. This solid state polymerization chip was supplied to an extruder type spinning machine and melt-spun at a spinning temperature of 300 ° C. At this time, a metal nonwoven fabric having an absolute filtration diameter of 15 μm was used as a filter, and a 0.6 mmφ round hole was used as the base. Subsequently, the film was subjected to a drawing heat treatment at a temperature of 250 ° C. and then subjected to a relaxation treatment to obtain a drawn yarn of 1100 dtex / 140 filament. The strength of this yarn was 8.3 cN / dtex, the elongation was 14.5%, the dry heat shrinkage was 4.1%, and the light resistance was good. The raw yarn had a cooling crystallization peak temperature Tc2 by DSC of 197 ° C., and the temperature difference (ΔT) from the temperature rising crystallization peak temperature Tc1 was 56 ° C. The results are shown in Table 1.

Examples 2 to 5 and Comparative Example 1 and Comparative Example 2
In Examples 2 to 5, polymerization was carried out in the same manner as in Example 1 except that the addition amount of the titanium compound as a polycondensation catalyst was changed, and spinning and stretching were performed using chips after solid-phase polymerization. The properties of the raw yarn were good and the light resistance was also excellent.

  On the other hand, Comparative Example 1 with a small amount of titanium was inferior in polymerization reactivity, so the polymerization time was very long, and was stopped midway. Further, in Comparative Example 2 having a large amount of titanium, the strength and elongation of the raw yarn were low and the toughness was poor, the light resistance was also poor, and many coarse foreign matters of 5 μm or more were observed. Table 1 shows the results of thermal crystallization by DSC and raw yarn characteristics.

Examples 6-10
Polymerization was carried out in the same manner as in Example 1 except that the catalysts B to F were used, and spinning and stretching were performed using chips after solid phase polymerization. The properties of the raw yarn were good and the light resistance was also excellent. Table 1 shows the results of thermal crystallization by DSC and raw yarn characteristics.

Example 11 and Example 12
Except changing the addition amount of the heat processing liquid a, superposition | polymerization was performed similarly to Example 1, and it spun and extended | stretched using the chip | tip after solid-phase polymerization. The properties of the raw yarn were good and the light resistance was also excellent. Table 1 shows the results of thermal crystallization by DSC and raw yarn characteristics.

Comparative Example 3
Polymerization was carried out in the same manner as in Example 1 except that no heat treatment liquid or fine particles were added, and spinning and stretching were performed using chips after solid-phase polymerization. The strength and elongation of the raw yarn were low and the toughness was inferior, and the light resistance was also inferior. Table 1 shows the results of thermal crystallization by DSC and raw yarn characteristics.

Comparative Example 4 and Comparative Example 5
Except changing the addition amount of the heat processing liquid a, superposition | polymerization was performed similarly to Example 1, and it spun and extended | stretched using the chip | tip after solid-phase polymerization. The strength and elongation of the raw yarn were low and the toughness was inferior, and the light resistance was also inferior. Table 2 shows the thermal crystallization characteristics by DSC and the results of the raw yarn characteristics.

Comparative Example 6
Heat treatment liquid c (5 ppm of metal atom in polyester) was added, and talc was pretreated (pulverized and classified) and refined (average particle size 0.95 μm), and 250 ppm was added to polyester Each was polymerized in the same manner as in Example 1, and was spun and stretched using the chips after solid phase polymerization. The strength and elongation of the raw yarn were low and the toughness was inferior, and the light resistance was also inferior. Table 2 shows the thermal crystallization characteristics by DSC and the results of the raw yarn characteristics.

Examples 13-15
Polymerization was carried out in the same manner as in Example 1 except that the treatment liquids b to d were used by changing the heat treatment liquid, and spinning and stretching were performed using the chips after solid phase polymerization. The properties of the raw yarn were good and the light resistance was also excellent. Table 2 shows the thermal crystallization characteristics by DSC and the results of the raw yarn characteristics.
Example 16 and Example 17
Instead of the heat treatment liquid of Reference Example 2, Example 16 is a talc pretreated (pulverized, classified) and refined (average particle size 0.95 μm) added 1000 ppm to the polyester (Example 15) Also, Example 17 was the same as Example 1 except that kaolin was pretreated (pulverized and classified) and refined (average particle size: 1.05 μm) was added to 1500 ppm of polyester. Polymerization was performed, and spinning and stretching were performed using the chips after solid-phase polymerization. These raw yarn characteristics were all good and light resistance was also excellent. Table 2 shows the thermal crystallization characteristics by DSC and the results of the raw yarn characteristics.

Comparative Example 7 and Comparative Example 8
Comparative Example 7 was obtained by increasing the amount of refined talc used in Example 16, and Comparative Example 8 was performed except that the amount of refined kaolin used in Example 17 was increased. Polymerization was carried out in the same manner as in Example 1, and spinning / stretching was performed using the chips after solid-phase polymerization. Both Comparative Example 7 and Comparative Example 8 were low in yarn strength and elongation and inferior in toughness, and inferior in light resistance. Moreover, many coarse foreign matters of 5 μm or more were observed. Table 2 shows the thermal crystallization characteristics by DSC and the results of the raw yarn characteristics.

Comparative Example 9
Spinning and stretching were performed in the same manner as in Example 1 except that the chip (IV = 0.83) extracted in the middle of the solid phase polymerization in Example 1 was used. The strength and elongation of the raw yarn were low and the toughness was inferior, and the light resistance was also inferior. Table 2 shows the thermal crystallization characteristics by DSC and the results of the raw yarn characteristics.

Example 18 and Example 19
Spinning and spinning were performed in the same manner as in Example 1 except that the chip having a different solid phase polymerization time in Example 1 (IV = 0.95 in Example 18 and IV = 1.01 in Example 19) was used. Stretched. The properties of the raw yarn were good and the light resistance was also excellent. The results are shown in Table 3.

Example 20 and Example 21
Using the chips after solid phase polymerization in Example 1, spinning was carried out at different spinning temperatures and residence times to obtain raw yarns having different COOH amounts. The raw yarn characteristics and light resistance were also good. Table 3 shows the results of thermal crystallization characteristics and raw yarn characteristics by DSC.
Example 22 and Example 23
Polymerization was carried out in the same manner as in Example 1 except that DEG was changed by adding DEG at the time of polymer production, and spinning and stretching were performed using the chips after solid-phase polymerization. The raw yarn characteristics and light resistance were also good. Table 3 shows the results of thermal crystallization characteristics and raw yarn characteristics by DSC.

Comparative Example 10
As a polycondensation catalyst, polymerization was performed in the same manner as in Example 1 except that 340 ppm in terms of antimony atoms was added to a polymer from which antimony trioxide (manufactured by Sumitomo Metal Mining Co., Ltd.) was obtained. Spinning and drawing. The strength and elongation of the raw yarn were low and the toughness was inferior, and the light resistance was also inferior. Moreover, many coarse foreign matters of 5 μm or more were observed. Table 3 shows the results of thermal crystallization characteristics and raw yarn characteristics by DSC.

Claims (7)

  A polyester containing 0.5 to 150 ppm of a titanium compound in terms of titanium atom as a polycondensation catalyst, (1) a cooling crystallization peak temperature Tc2 measured with a differential scanning calorimeter (DSC) is 185 ° C. or higher, and The temperature difference (ΔT) with respect to the temperature rising crystallization peak temperature Tc1 is 40 ° C. or higher, (2) the intrinsic viscosity is 0.75 or higher, and (3) the strength is 6.0 cN / dtex or higher. Polyester fiber for industrial materials.   The polyester fiber for industrial materials according to claim 1, wherein the titanium compound is a titanium complex.   The polyester fiber for industrial materials according to claim 2, wherein the chelating agent of the titanium complex is hydroxycarboxylic acid.   The polyester fiber for industrial materials according to claim 2, wherein the chelating agent of the titanium complex is a hydroxy polyvalent carboxylic acid or a hydroxy nitrogen-containing polyvalent carboxylic acid.   5. The polyester fiber for industrial materials according to claim 1, wherein the number of coarse particles of 5 μm or more in the fiber is 10/10 mg fiber or less.   The polyester fiber for industrial materials according to any one of claims 1 to 5, wherein the diethylene glycol content is 1.3 wt% or less and the carboxyl end group content is 40 eq / ton or less.   The polyester fiber for industrial materials according to any one of claims 1 to 6, wherein the polyester fiber has an elongation of 8 to 30% and a dry heat shrinkage at 150 ° C of 2 to 15%.