JPH07157921A - Polyester monofilament - Google Patents

Abstract

PURPOSE:To obtain polyester monofilament suitable as a papermaking canvas excellent in hydrolytic and flexing abrasion resistances. CONSTITUTION:This polyester monofilament comprises a composition containing an organosilicon compound such as polyorganosiloxandiol in an amount of 0.1-10wt.% based on the whole in polyethylene terephthalate having g 0.6 intrinsic viscosity and <=10g equiv./10<6>g terminal carboxyl group concentration.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyester monofilament which is excellent in hydrolysis resistance and flex abrasion resistance and is suitable for papermaking canvas.

[0002]

2. Description of the Related Art Polyethylene terephthalate has strength,
It has excellent properties such as chemical resistance, heat resistance, weather resistance, and electrical insulation, and is widely used in industrial applications.
Among the industrial applications, monofilaments used especially for papermaking machines are woven into a canvas cloth and used as a belt for continuously transporting a paper sheet in a wet state, which is made by papermaking, by pressing it on a drying cylinder and drying it. , High hydrolysis resistance and bending abrasion resistance are required.

As a method of increasing the hydrolysis resistance of polyester filaments, a method of reducing the terminal carboxyl group concentration of polyester in advance is known, and a method of adding an epoxy compound (Japanese Patent Publication No. 44-27911).
JP-A-54-6051), a method of adding a carbodiimide compound (JP-B-1-15604, JP-A-3-104919, etc.), a method of adding a carbodiimide compound and a fluorine compound (JP-A-4-149268). No.) etc. have been proposed. According to these methods, the hydrolysis resistance is improved to some extent, but there is a problem that the flexing abrasion resistance is not sufficient.

On the other hand, as a method for increasing the flex wear resistance,
A method of adding metal particles (JP-A-3-76813), a method of coating the surface of a monofilament with a silicon compound (JP-A-3-249273, 3-269169), and a core-sheath composite yarn of polyester and nylon. Method (JP-A-2
No. 145894) has been proposed. According to these methods, although the flexing abrasion resistance is improved to some extent, there are problems that not only the hydrolysis resistance is insufficient, but also the contact portion of the belt such as the roller surface is abraded.

As a method of imparting lubricity to polyester, a method of adding a fluororesin having a particle size of 50 μm or less (Japanese Patent Laid-Open No. 54-124055) has been proposed. According to this method, the lubricity is improved to some extent, but when the monofilament having a small diameter is used, there is a problem that the flexing abrasion resistance is not sufficient.

Further, Japanese Patent Application Laid-Open No. 60-194118 discloses a monofilament made of polyester containing an organic polysiloxane. The monofilament has a high knot strength so as to be suitable as a fishery material. However, it cannot be used for a papermaking machine that requires high hydrolysis resistance.

[0007]

DISCLOSURE OF THE INVENTION The present invention is intended to provide a polyester monofilament having excellent hydrolysis resistance and flex abrasion resistance.

[0008]

Means for Solving the Problems The present invention is to solve the above problems, and its gist is to provide polyethylene terephthalate (PET) with an intrinsic viscosity of 0.6 or more and a terminal carboxyl group concentration of 10 g equivalent / 10 ⁶ g or less, A polyester monofilament comprising a composition containing an organosilicon compound in an amount of 0.1 to 10% by weight based on the whole.

The present invention will be described in detail below. In the present invention, PET is preferably a homopolymer, but may contain a copolymerization component as long as the effects of the present invention are not impaired. Specific examples of the copolymerization component include isophthalic acid, succinic acid, adipic acid, suberic acid, dodecanedioic acid, azelaic acid, sebacic acid, 1,3-
Propanediol, 1,4-butanediol, 1,6-hexanediol, hydroquinone, 4,4'-dihydroxydiphenyl, bisphenol A, 1,4-naphthalenedicarboxylic acid, 2,4-naphthalenedicarboxylic acid, 2,6- Naphthalenedicarboxylic acid, 4,4'-diphenyldicarboxylic acid, diphenoxyethanedicarboxylic acid, 3-hydroxypropanoic acid, 4-hydroxybutanoic acid, ε-caprolactone, 4-hydroxybenzoic acid, 2-hydroxy-6-
Naphthoic acid and the like can be mentioned. Further, an unsaturated dicarboxylic acid having an intermolecular crosslinkable structure, an unsaturated diol, and a trifunctional or higher functional monomer component may be copolymerized,
Various additives may be included.

The monofilament of the present invention has an intrinsic viscosity
0.6 or more, preferably 0.7 to 0.9, and a terminal carboxyl group concentration of 10 g equivalent / 10 ⁶ g or less, preferably 5 g equivalent / 10
Consists of less than ⁶ g PET. When the intrinsic viscosity is less than 0.6, mechanical properties such as tensile strength are deteriorated, which is not preferable. Also, the terminal carboxyl group concentration is 10 g equivalent / 10
If it exceeds ⁶ g, hydrolysis resistance is not sufficient.

The terminal carboxyl group concentration is 10 g equivalent / 10 ⁶ g
To the following, in any step up to the melt spinning step,
A carbodiimide compound such as 2,6,2 ′, 6′-tetraisopropyldiphenylcarbodiimide (TPC) and a terminal carboxyl group blocking agent such as an epoxy compound such as phenylglycidyl ether may be added and reacted. For example, the terminal carboxyl group concentration is 20 g equivalent / 10 ⁶ g
The following PET is used, and TPC is 0.1 to 3.
It may be added by 0% by weight and melt-spun by using an extruder.

Examples of the organosilicon compound in the present invention include polyorganosiloxane compounds and silane coupling agents. Specific examples of the polyorganosiloxane compound include polydimethylsiloxane, polydiphenylsiloxane, polymethylphenylsiloxane, and the like, and polyorganosiloxanediol having a terminal group of these as a hydroxyl group. Further, specific examples of the silane coupling agent include methyltrimethoxysilane,
Alkoxy group, thiol group, carboxyl group, amino group, vinyl group or epoxy on the terminal silicon atom of dimethyldimethoxysilane, γ-mercaptopropyltrimethoxysilane, N- (trimethoxysilylpropyl) -ethylenediamine, vinyltriacetoxysilane, etc. Examples thereof include organic silicon compounds having a group bonded. Among the organosilicon compounds, particularly preferable ones have a molecular weight of 600 to 10
000 polyorganosiloxane diols such as polydimethylsiloxane diol and polydiphenylsiloxane diol. These compounds have good dispersibility in polyester and are particularly excellent in the effects of improving strength and flexural abrasion resistance.

It is necessary that the content of the organosilicon compound is 0.1 to 10% by weight based on the whole. When the content of the organosilicon compound is less than 0.1% by weight, the effect of improving flexural wear resistance is insufficient, and when it exceeds 10% by weight, mechanical properties such as tensile strength become poor, which is not preferable.

The organosilicon compound can be incorporated into the polyester at any stage from the polymerization to the spinning process,
You may blend as a master chip at the time of spinning. However, it is preferable from the viewpoint of strength of the obtained monofilament to add and react a reactive organosilicon compound during the polymerization of polyester.

[0015]

The monofilament of the present invention has an excellent resistance to hydrolysis because it has a low concentration of terminal carboxyl groups and is excellent in hydrolysis resistance.

[0016]

EXAMPLES Next, the present invention will be described in detail with reference to examples. In addition, the measuring method of the characteristic value in an Example is as follows. (1) Intrinsic viscosity [η] It was determined from the solution viscosity measured at a temperature of 20 ° C using an equal weight mixture of phenol and ethane tetrachloride as a solvent. (2) Tensile strength Tensilon UTM-4-100 type manufactured by Orientec Co., Ltd. was used for measurement at a sample length of 10 cm and a tensile speed of 10 cm / min. (3) Hydrolysis resistance [η] and tensile strength of a sample treated with saturated steam at 130 ° C for 15 days in an autoclave were measured and evaluated by comparing with the value before treatment. (The value after processing is the same as the value before processing.
70% or more pass. ) (4) Bending abrasion resistance With a yarn abrasion tester used in JIS L 1095 7.10.2B method, a load of 0.2 g / d is applied to the monofilament, the friction speed is 60 times / min, the friction angle is 110 degrees, The test was conducted under the conditions of a round trip distance of 2.5 cm, a sample length of 20 cm, a friction element and a diameter of 1.0 mm hard steel, and the number of times until the filament was cut was measured. (Passed 6000 times or more.)

Example 1 A slurry of terephthalic acid and ethylene glycol in a molar ratio of 1 / 1.6 was continuously fed to an esterification reaction vessel containing bis (β-hydroxyethyl) terephthalate and its low polymer (BHET). , Temperature 250 ℃, pressure 0.05kg /
Perform the esterification reaction under the conditions of cm ² and residence time of 8 hours,
BHET having an esterification reaction rate of 95% was continuously obtained. 50 kg of this BHET was transferred to a polymerization tank and heated to 280 ° C., and 2 × 10 ⁻⁴ mol of antimony trioxide as a catalyst was added to 1 mol of the acid component constituting the polyester to produce polydimethylsiloxanediol having a molecular weight of 2000. Polyester The amount was 2% by weight of the composition. Then, the pressure was gradually reduced, and the polycondensation reaction was finally performed at 280 ° C. under a reduced pressure of 0.1 torr for 2.5 hours to obtain a polyester chip of [η] 0.68. By solid-phase polymerizing this chip at 180 ° C. under reduced pressure, a solid-state polymerized polyester chip having [η] 0.85 and a terminal carboxyl group concentration of 15.0 g equivalent / 10 ⁶ g was obtained. 2% by weight of TPC was added to the obtained polyester chips and the mixture was supplied to an extruder type melt spinning machine, and a spinneret (diameter 90 mm) having a hole diameter of 2.4 mm and 6 holes was used, and the speed was 33 m / min.
It was spun at 310 ° C., quenched in a water bath at 80 ° C., and divided into 6 parts to obtain an undrawn yarn. The obtained undrawn yarn was drawn 5.7 times and heat-treated at 295 ° C. to obtain a monofilament having a diameter of 0.4 mm.

Examples 2 to 7 The procedure of Example 1 was repeated, except that the type and amount of the organosilicon compound added were changed as shown in Table 1.

Examples 8 to 9 The procedure of Example 1 was repeated, except that the amount of TPC added was changed as shown in Table 1.

Example 10 The procedure of Example 1 was repeated except that phenylglycidyl ether was used instead of TPC.

Example 11 Example 11 was carried out in the same manner as in Example 1 except that PET having [η] 0.65 was used.

Comparative Examples 1 and 2 Example 1 was repeated except that the addition amount of the organosilicon compound was changed as shown in Table 1.

Comparative Example 3 The procedure of Example 1 was repeated, except that the amount of TPC added was changed as shown in Table 1.

Comparative Example 4 The procedure of Example 1 was repeated, except that PET having [η] 0.55 was used.

Table 1 shows the results of measurement of hydrolysis resistance and flex wear resistance of the monofilaments obtained in the above Examples and Comparative Examples.

[0026]

[Table 1]

[0027]

Industrial Applicability According to the present invention, there is provided a polyester monofilament which is excellent in hydrolysis resistance and bending abrasion resistance and is suitable for papermaking canvas. Further, the monofilament of the present invention can be manufactured with good operability.

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Claims (2)

[Claims] 1. A polyester monofilament comprising a composition in which 0.1 to 10% by weight of an organosilicon compound is contained in polyethylene terephthalate having an intrinsic viscosity of 0.6 or more and a terminal carboxyl group concentration of 10 g equivalent / 10 ⁶ g or less. 2. The polyester monofilament according to claim 1, wherein the organosilicon compound is a polyorganosiloxane diol.