JPS6315970A - Gut for racket - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a racket gut used for ball games such as tennis and badminton.

C. Conventional technology and problems] These ball games have standardized standards for courts, nets, etc., but rackets do not have these restrictions.
The ball player himself can freely select the material, weight, and tension of the gut.

The physical properties required for Guttu include breaking strength, elastic modulus, abrasion resistance, weather resistance, water resistance, and durability, but since it is an outdoor ball game, the tensile strength even when exposed to rain and dew. (Usually about 55 bond in the case of tennis rackets) It is required that the bond does not change and that the durability is high.

Guts made from sheep (sheep intestine), which have traditionally been considered the best guts, have excellent repulsion against the ball and are difficult to slip, but they lack water resistance and are expensive. Therefore, in recent years, nylon guts have been frequently used instead of sheep guts.

However, the strength of nylon in water is reduced to about 80 to 90% of that in air, although it is not as strong as sieve, and when used for a long period of time, it yellows and its strength also decreases. For example, even with 6-nylon high-strength monofilament, its dry tensile strength is between 6.8 and 8.6 g/d (d is denier). , ■Tensile strength is 5.4-7.5g/
No dL. This means that the Gantt may break or stretch while being used outdoors.

[Means for solving problems]

The present inventor discovered that a racket string made of melt-processable polyester (hereinafter referred to as "liquid crystalline polyester") capable of forming an anisotropic melt phase solves the above problems at once, and completed the present invention. It's arrived.

Hereinafter, the liquid crystalline polyester used in the present invention will be specifically explained.

The liquid crystalline polyester used in the present invention is a melt-processable polyester, and has the property that polymer molecular chains are regularly arranged in parallel in a molten state. The state in which the molecules are arranged in this way is often called the liquid crystal state or the nematic phase of liquid crystal materials. Such polymers are monomers that are generally elongated (flat, fairly rigid along the long axis of the molecule, and have multiple chain extensions, usually in either a coaxial or parallel relationship). Manufactured from.

The nature of the anisotropic melt phase can be confirmed by conventional polarization testing using crossed polarizers. More specifically, the anisotropic melt phase can be confirmed by using a Leitz polarizing microscope and observing a sample placed on a Leitz hot stage at a magnification of 40 times under a nitrogen atmosphere.

The polymer is optically anisotropic. That is, it transmits light when examined between orthogonal polarizers. If the sample is optically anisotropic, polarized light will pass through it even if it is at rest.

Constituent components of the polymer that forms the anisotropic melt phase as described above include: ■ Consisting of one or more of aromatic dicarboxylic acids and alicyclic dicarboxylic acids; ■ Consisting of aromatic diols, ring diols, and aliphatic diols. Consists of one or more aromatic hydroxycarboxylic acids; Consists of one or more aromatic thiol carboxylic acids; Aromatic dithiol, aromatic thiol phenol.
Polyesters consisting of one or more of aromatic hydroxyamines and aromatic diamines, etc. Polyesters that form an anisotropic melt phase include polyesters consisting of ■)■ and ■■) Polyester consisting of only ■ Polyester consisting of ■) ■, ■ and ■ ■) Polythiol ester consisting only of ■ ■) Polythiol ester consisting of ■ and ■ ■) Polythiol ester consisting of ■ and ■ ■) ■ and ■ It is composed of a combination of polyesteramide consisting of ■) and ■ and polyesteramide consisting of ■ and ■.

Furthermore, although not included in the above range of combinations of ingredients,
Polymers that form an anisotropic melt phase include aromatic polyazomethines, and specific examples of such polymers include poly-2-methyl-1,4-phenylenenitrilomethylidine-1,4-phenylenemethylidine. ) ; poly
trilo-2-methyl-1,4-phenylenenitrilomethylidine-1,4-phenylenemethylidine); Can be mentioned.

Furthermore, although not included in the above range of combinations of ingredients,
Polyester carbonate is included as a polymer that forms an anisotropic melt phase. It may consist essentially of 4-oxybenzoyl units, dioxyphenyl units, dioxycarbonyl units and terephthaloyl units.

The compounds constituting the above-mentioned components I) to (2) are listed below.

As the aromatic dicarboxylic acid, terephthalic acid, 4.4'
-diphenyl dicarboxylic acid, 4.4'-) diphenyl dicarboxylic acid, 2,6-knack dicarboxylic acid, diphenyl ether-4,4''-dicarboxylic acid, diphenoxyethane-4,4''-dicarboxylic acid, diphenoxybutane- 4,4'-dicarboxylic acid, diphenylethane-4,4
゛-dicarboxylic acid, isophthalic acid, diphenyl ether-3,3゛-dicarboxylic acid, diphenoxyethane-3,
Aromatic dicarboxylic acids such as 3'-dicarboxylic acid, diphenylethane-3,3'-dicarboxylic acid, naphthalene-1,6-dicarboxylic acid, or chloroterephthalic acid, dichloroterephthalic acid, bromoterephthalic acid, methylterephthalic acid, Examples include alkyl, alkoxy or halogen substituted products of the aromatic dicarboxylic acids such as dimethyl terephthalic acid, ethyl terephthalic acid, methoxyterephthalic acid and ethoxyterephthalic acid.

Examples of alicyclic dicarboxylic acids include alicyclic dicarboxylic acids such as trans-1゜4-cyclohexanedicarboxylic acid, cis-1,4=cyclohexanedicarboxylic acid, and 1,3-cyclohexanedicarboxylic acid, or trans-1,4-( 1
-methyl)cyclohexanedicarboxylic acid, trans-1
, 4-(1-chloro)cyclohexanedicarboxylic acid, etc.
Examples include alkyl, alkoxy, or halogen-substituted products of the above alicyclic dicarboxylic acids.

Aromatic diols include hydroquinone, resorcinol, 4.4'-dihydroxydiphenyl, 4.4'-dihydroxytriphenyl, 2,6-naphthalenediol,
4.4'-dihydroxydiphenyl ether, bis(4
-hydroxyphenoxy)ethane, 3.3'-dihydroxydiphenyl, 3.3''-dihydroxydiphenyl ether, 1,6-naphthalenediol, 2,2-bis(
4-hydroxyphenyl)propane, 2,2-bis(4
Aromatic diols such as -hydroxyphenyl)methane or chlorohydroquinone, methylhydroquinone, 1
-Butylhydroquinone, phenylhydroquinone, methoxyhydroquinone, phenoxyhydroquinone=
Examples include alkyl, alkoxy or halogen substituted products of the above aromatic diols such as 4-chlorresorcin and 4-methylresorcin.

Examples of alicyclic diols include trans-1,4-cyclohexanediol, cis-1,4-cyclohexanediol, trans-1,4-cyclohexane dimetatool,
Alicyclic diols such as cis-1,4-cyclohexane dimetatool, trans-1,3-cyclohexanediol, cis-1,2-cyclohexanediol, trans-1,3-cyclohexane dimetatool, or trans-L4 - (1-methyl)cyclohexanediol,
Examples include alkyl, alkoxy or halogen substituted products of the above alicyclic diols such as trans-L4-(1-chloro)cyclohexanediol.

Aliphatic diols include ethylene glycol, 1,3
-Light chain or branched aliphatic diols such as propanediol, 1,4-butanediol, neopentyl glycol and the like can be mentioned.

Examples of aromatic hydroxycarboxylic acids include 4-hydroxybenzoic acid, 3-hydroxybenzoic acid, and 6-hydroxybenzoic acid.
Aromatic hydroxycarboxylic acids such as 2-naphthoic acid and 6-hydroxy-1-naphthoic acid, or 3-methyl-4-
Hydroxybenzoic acid, 3.5-dimethyl-4-hydroxybenzoic acid, 2,6-dimethyl-4-hydroxybenzoic acid, 3-methoxy-4-hydroxybenzoic acid, 3.5-
Dimethoxy-4-hydroxybenzoic acid, 6-hydroxy-5-methyl-2-naphthoic acid, 6-hydroxy-5-
Methoxy-2-naphthoic acid, 3-chloro-4-hydroxybenzoic acid, 2-chloro-4-hydroxybenzoic acid, 2
．． 3-dichloro-4-hydroxybenzoic acid, 3,5-dichloro-4-hydroxybenzoic acid, 2,5-dichloro-
4-hydroxybenzoic acid, 3-bromo-4-hydroxybenzoic acid, 6-hydroxy-5-chloro-2-naphthoic acid, 6-hydroxy-7=chloro-2-naphthoic acid, 6
Examples include alkyl, alkoxy or halogen substituted aromatic hydroxycarboxylic acids such as -hydroxy-5,7-dichloro-2-naphthoic acid.

Examples of aromatic mercaptocarboxylic acids include 4-mercaptobenzoic acid, 3-mercaptobenzoic acid, 6-mercapto-2-naphthoic acid, and 7-mercapto-2-naphthoic acid.

Examples of the aromatic dithiol include benzene-1,4-dithiol, benzene-1,3-dithiol, 2,6-naphthalene-dithiol, and 2,7-naphthalene-dithiol.

Examples of aromatic mercaptophenol include 4-mercaptophenol, 3-mercaptophenol, 6-mercaptophenol, and 7-mercaptophenol.

Aromatic hydroxyamine, aromatic diamine is 4-
Aminophenol, N-methyl-4-aminephenol, 1,4-phenylenediamine, N-methyl-1,4-
Phenylenediamine, N,N''-dimethyl-1,4-phenylenediamine, 3-aminophenol, 3-methyl-4-aminophenol, 2-di-4-aminophenol, 4-amino-1-naphthol, 4 -Amino-4
'-Hydroxydiphenyl, 4-amino-4°-hydroxydiphenyl ether, 4-amino-4'-hydroxydiphenylmethane, 4-amino-4''-hydroxydiphenyl sulfide, 4.4'-diaminophenyl sulfide (thiodianiline), 4. 4'-diaminodiphenylsulfone, 2,5-diaminotoluene, 4,4'-ethylene dianiline, 4,4'-diaminodiphenoxyethane, 4.4"-diaminodiphenylmethane (methylene dianiline"), 4.4 Examples include °-diaminodiphenyl ether (oxydianiline).

The above polymer ■) to 'i1) consisting of each of the above components is
Depending on the constituent components, the composition ratio in the polymer, and the sea fence distribution, some may or may not form an anisotropic melt phase, but the polymer used in the present invention does not form an anisotropic melt phase among the above polymers. limited to those that form.

The polyesters of 1), n), and II[) and the polyesteramides of ①), which are polymers that form an anisotropic melt phase suitable for use in the present invention, have functional groups that form the required repeating units by condensation. It can be produced by various ester-forming methods that allow organic monomer compounds having the following to react with each other. For example, the functional groups of these organic monomer compounds may be carboxylic acid groups, hydroxyl groups, ester groups, acyloxy groups, acid halides, amine groups, and the like. The above organic monomer compounds can be reacted without the presence of a heat exchange fluid by a melt acidolysis method. In this method, the monomers are first heated together to form a molten solution of the reactants. As the reaction continues, solid polymer particles become suspended in the liquid. Vacuum may be applied to facilitate removal of by-product volatiles (eg acetic acid or water) during the final stage of condensation.

Slurry polymerization techniques can also be employed to form fully aromatic polyesters suitable for use in the present invention. In this process, a solid product is obtained in suspension in a heat exchange medium.

Regardless of whether the above-mentioned melt acidolysis method or slurry polymerization method is employed, the organic monomer reactant that induces the fully aromatic polyester is a modified form in which the hydroxyl groups of such monomers are esterified at room temperature (i.e., , as a lower acyl ester). The lower acyl group preferably has about 2 to 4 carbon atoms. Preferably, an acetate ester of such an organic monomer reactant is subjected to the reaction.

Furthermore, representative examples of catalysts that can optionally be used in either the melt acidolysis method or the slurry method include dialkyltin oxides (e.g., dibutyltin oxide), diaryltin oxides, titanium dioxide, antimony trioxide, alkoxytitanium silicates, titanium alkoxides. , alkali and alkaline earth metal salts of carboxylic acids (e.g. zinc acetate), Lewis (e.g. BF3), hydrogen halides (e.g. I
Examples include gaseous acid catalysts such as IcI). The amount of catalyst used is generally about 0.0% based on the total weight of monomers.
0.01 to 1% by weight, especially about 0.01 to 0.2% by weight.

The fully aromatic polymers used in this invention tend to be substantially insoluble in common solvents and are therefore unsuitable for solution processing.

However, as previously mentioned, these polymers can be readily processed using conventional melt processing techniques. Preferred fully aromatic polymers for the frame are somewhat tolerant of pentafluorophenol.

Fully aromatic polyesters suitable for use in the present invention generally have a weight average molecular weight of about 2,000 to 200,000.
, preferably about 10,000 to 50,000, particularly preferably about 20,000 to 25,000. On the other hand, suitable fully aromatic polyester amides generally have a molecular weight of about s,ooo to 50,000, preferably about 10,000.
~30,000, e.g. 15,000-17,000
It is. Such molecular weight measurements can be carried out by gel permeation chromatography as well as other standard methods of measuring polymers that do not involve solution formation, such as quantification of end groups by infrared spectroscopy on compression molded films. Alternatively, the molecular weight can be measured using a light scattering method using a pentafluorophenol solution.

The fully aromatic polyesters and polyesteramides described above also yield 0.1% of pentafluorophenol at 60°C.
At least about 2.0 when expressed as 78% concentration by weight
a/g, for example about 2.0 to 10. The logarithmic viscosity (1, V,) in Odi/g is generally indicated.

The polymer exhibiting an anisotropic melt phase used in the present invention is preferably an aromatic polyester or an aromatic polyester amide, and a polyester partially containing an aromatic polyester or an aromatic polyester amide in the same molecular chain is also a preferred example. .

Preferred examples of compounds constituting these are naphthalene compounds such as 2°6-naphthalene dicarboxylic acid, 2,6-dihydroxynaphthalene, 1,4-dihydroxynaphthalene, and 6-hydroxy-2-naphthoic acid; Biphenyl compounds such as diphenyl dicarbon a, 4.4''-dihydroxybiphenyl, the following general formulas (1), (II
) or (III); (However, X: alkylene CC+ to C4), alkylidene, -O-, -5O-1-SO, -, -S-, -CO- Hz)n-(n=1~4), -0(C1lz
)llO-(n・1 to 4)) Para-substituted benzene compounds such as p-hydroxybenzoic acid, terephthalic acid, hydroquinone, p-aminephenol, and p-phenylenediamine, and their nuclear-substituted benzene compounds (substituents selected from chlorine, bromine, methyl, phenyl, 1-phenylethyl), isophthalic acid,
It is a meta-compatible benzene compound such as resorcinol.

A preferred example of the polyester partially containing the above-mentioned constituents in the same molecular chain is polyalkylene terephthalate, in which the alkyl group has 2 to 4 carbon atoms.

Among the above-mentioned components, a more preferred example is one containing one or more compounds selected from naphthalene compounds, biphenyl compounds, and para-substituted benzene compounds as an essential component. Among the p-substituted benzene compounds, p-hydroxybenzoic acid, methylhydroquinone and 1-phenylethylhydroquinone are particularly preferred examples.

The following are exemplified as specific combinations of constituent components.

In the formula, Z is a substituent selected from -C1, -Br, and -CR2, and X is alkylene (C+ to C4), alkylidene, -O-, -5O-2-so! It is a substituent selected from -, -s-, and -co-.

Particularly preferred anisotropic melt phase forming polyesters for use in the present invention include repeating units containing naphthalene moieties such as 6-hydroxy-2-naphthoyl, 2,6-dihydroxynaphthalene and 2,6-dicarboxynaphthalene. It is contained in an amount of about 10 mol% or more. Preferred polyesteramides are those containing repeating units of the naphthalene moiety described above and a moiety consisting of 4-aminophenol or 1,4-phenylenediamine. Specifically, the details are as follows.

(]) A polyester consisting essentially of the following repeating units I and ■.

This polyester contains about 10 to 90 mol% of unit ■ and about 1
Contains 0 to 90 mol % of units (■). In one embodiment, Unit I is present in an amount of about 65-85 mol%, preferably about 70-80 mol% (eg, about 75 mol%). In another embodiment, the unit ■ is present in much lower concentrations of about 15-35 mole %, preferably about 20-30 mole %.

In addition, at least a portion of the hydrogen atoms bonded to the ring may optionally be selected from the group consisting of an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, halogen, phenyl, substituted phenyl, and a combination thereof. It may be substituted with selected substituents.

(2) A polyester consisting essentially of the following repeating units ■, ■, and ■.

The polyester contains about 30-70 mole percent unit weight. The polyester preferably has about 40 to 60
Contains mol % of units I, about 20-30 mol % of units (), and about 20-30 mol % of units -. In addition, at least some of the hydrogen atoms bonded to the ring may optionally be
It may be substituted with a substituent selected from the group consisting of an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, halogen, phenyl, substituted phenyl, and combinations thereof.

(3) Polyester consisting essentially of the following repeating units I, ■, ■, and ■: (wherein R means methyl, chloro, bromo, or a combination thereof, and is a substituent for the hydrogen atom on the aromatic ring. ), and about 20 to 60 mol% of unit I,
Approximately 5 to 18 mol% 1 of unit ■, approximately 5 to 35 mol % of unit III
mol %, and the unit ■ in an amount of about 20 to 40 mol %. The polyester preferably has about 35 to 45
Mol% unit I, about 10-15 mole% unit ■, about 15
Contains ~25 mole % units ■, and about 25 to 35 mole percent units ■. However, the total molar concentration of units ■ and ■ is substantially equal to the molar concentration of unit ■.

In addition, at least some of the hydrogen atoms bonded to the ring are
Optionally, an alkyl group having 1 to 4 carbon atoms, 1 to 4 carbon atoms
may be substituted with a substituent selected from the group consisting of an alkoxy group, halogen, phenyl, substituted phenyl, and combinations thereof. This fully aromatic polyester was converted into pentafluorophenol by 0.3w at 60°C.
/vχ concentration (both 2.0 d1/
g typically exhibits a logarithmic viscosity of, for example, 2.0 to 10.0 Lij/g.

(4) Polyester consisting essentially of the following repeating units I, ■, ■ and ■: ■ General formula (0-Ar-0)- (wherein Ar means a divalent group containing at least one aromatic ring) dioxyaryl unit represented by OO II II ■ General formula -(C-Ar'-C) (wherein Ar' means a divalent group containing at least one aromatic ring) dicarboxyaryl units, and about 20 to 40 mol% of unit I, more than 10 mol% of unit (■) and up to about 50 mol%, more than 5 mol% of unit (■) and up to about 30 mol%, and Unit ■ 5 mol%
30 mole % or less. The polyester preferably contains about 20 to 30 mole percent (e.g., about 2
5 mol%) unit ■, about 25 to 40 mol% (e.g. about 35 mol%)
mol%) unit ■, about 15 to 25 mol% (e.g., about 20 mol%) unit ■, and about 15 to 25 mol% (e.g., about 2
0 mol %) of the unit ■. In addition, at least some of the hydrogen atoms bonded to the ring may have a carbon number of 1
It may be substituted with a substituent selected from the group consisting of ~4 alkyl groups, C1-4 alkoxy groups, halogens, phenyls, substituted phenyls, and combinations thereof.

Units ■ and ■ have a symmetrical arrangement on one or more aromatic rings in which the divalent bonds connecting these units to other units on either side within the polymer backbone (e.g., on a naphthalene ring) When present, they are preferably symmetrical in the sense that they are disposed apart from each other or on a diagonal ring. However, asymmetric units such as those derived from resorcinol and isophthalic acid can also be used.

The preferred dioxyaryl unit ■ is and the preferred dicarboxyaryl unit ■ is It is.

(5) Polyester consisting essentially of the following repeating units I, ■ and ■: ■ General formula -(0-Ar-0) (wherein Ar means a divalent group containing at least one aromatic ring) Dioxyaryl unit represented by O○ ■ General formula -(C-Ar'-C) (wherein, Ar'
means a divalent group containing at least one aromatic ring), and the unit (■) is about 10 to 90 mol%, the unit (■) is about 5 to 45 mol%, and the unit (■) is about 10 to 90 mol%. It is contained in an amount of 5 to 45 mol%. The polyester preferably contains about 20 to 80 mole percent units, about 10 to 40 mole percent units, and about 10 to 40 mole percent units. More preferably, the polyester has about 60 to 80 mole % of units I;
It contains about 10 to 20 mol % of units (2) and about 10 to 20 mol % of units (2). In addition, hydrogen atoms with a small number of hydrogen atoms bonded to the ring (in some cases, alkyl groups having 1 to 4 carbon atoms, alkoxy groups having 1 to 4 carbon atoms, halogen, phenyl, substituted phenyl, and combinations thereof) may be substituted with a substituent selected from the group consisting of:

The preferred dioxyaryl unit ■ is and the preferred dicarboxyaryl unit ■ is It is.

(6) Polyesteramide consisting essentially of the following repeating units ■, ■, ■ and ■: a divalent group containing at least one aromatic ring or a divalent trans-
cyclohexane group), ■ General formula 4 Y
A r Z ) (wherein, Ar is a divalent group containing at least one aromatic ring, Y is 0, NH or NR, and Z is N
H or NR, respectively, R means an alkyl group having 1 to 6 carbon atoms or an aryl group), ■ General formula (0-Ar'-0) (wherein, Ar' represents at least one (means a divalent group containing an aromatic ring), and the unit (■) is approximately 10 to 90 mol%, the unit (■) is approximately 5 to 45 mol%, the unit (■) is approximately 5 to 45 mol%, and the unit (■) is approximately 10 to 90 mol%. It is contained in an amount of about 0 to 40 mol%. In addition, at least a portion of the hydrogen atoms bonded to the ring may optionally be a group consisting of an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, halogen, phenyl, substituted phenyl, or a combination thereof. may be substituted with a substituent selected from.

Preferred dicarboxyaryl units (2) are, preferred units (2) are, and preferred dioxyaryl units (2) are.

Furthermore, the polymer forming the anisotropic melt phase of the present invention includes:
A part of one polymer chain is composed of polymer segments that form an anisotropic melt phase as explained above, and the remaining part is composed of thermoplastic resin segments that do not form an anisotropic melt phase. Also includes polymers.

The above-mentioned liquid crystalline polyester is a high-strength material that has a self-reinforcing effect, and has a small linear expansion coefficient and a small molding shrinkage rate, so there is little dimensional deviation. While it has low melt viscosity and good fluidity, it can withstand high temperatures of 180-200°C. It has good chemical resistance, weather resistance, and hot water resistance, is extremely chemically inert, and does not affect other substances.

Liquid crystalline polyester contains common additives such as colorants,
Fillers and reinforcing materials may be added.

There are no particular limitations on the method for producing guttu using liquid crystalline polyester as a constituent material, as described above, and in the same way as the preparation of conventional polymeric strands or filaments, it is possible to produce guttu using a melt extrusion molding machine or a spinning machine. melt extrusion,
Or melt-spun, cooled and solidified at an appropriate drawdown ratio, and produced 3 gut filaments having any desired thickness.
Can be molded. This filament can be used directly as a monofilament without being cold-stretched, or the surface of the filament can be coated with a suitable surface treatment agent to prevent fuzzing during use. Alternatively, instead of a single filament, a plurality of filaments may be twisted together to form a single string, and if necessary, the twisted material may be further impregnated or coated with a suitable binder to form a string.

〔Effect of the invention〕

Liquid crystalline polyester racket guts are not only suitable because of the high strength, high modulus of elasticity, low coefficient of linear expansion, high vibration damping properties, and low difference in dry and wet strength of liquid crystalline polyester as a raw material, but also because of its surface properties. It can be said that it is perfect for gripping as it is difficult to slip due to small irregularities.

〔Example〕

The present invention will be further explained below with reference to Examples, but the present invention is not limited to these Examples.

Example 1 and Comparative Example 1 Resin A described later was used, L/D=20, compression ratio 2.
85 extruder, diameter 3. 280 from OI nozzle
It was extruded at ℃ and melt-spun, passed through water at a linear speed of 30 m/min with a drawdown ratio of 5 times, and wound up to a diameter of 1.
A 3 mm monofilament was obtained.

The obtained monofilament has a tensile strength of 7700 kg/
cm" and is the same as the nylon gutt (comparative example 1), but the water absorption rate is about 0.03%, and that of nylon is 1.
．． The strength of nylon decreases to about 6,000 kg/cm" when wet, whereas the monofilament of the present invention has a strength of 7,650 kg/cm".
/cmF, almost no decrease was observed. Next, regarding the same monofilament, we used a Suga Test Instruments Sunshine Super Long Weather Meter (Buttock EL-5UN-11C model).
After 2000 hours of repeating carbon arc lamp irradiation at 63°C for 48 minutes and 12 minutes of rain, the tensile strength was expressed as the strength retention rate compared to the value before irradiation, as shown in Table 1. Ta.

Table 1: As can be seen from the above measurement results, the Guttu of the present invention is an all-weather racket whose performance does not change in both dry and wet conditions, as typified by its strength and low hygroscopicity. It is extremely excellent.

Examples 2 to 4 Monofilaments were produced in the same manner as in Example 1 using Resin B (Example 2), Resin C (Example 3), and Resin D (Example 4), which will be described later, and the same measurements were carried out. I did it. The results are shown in Table 2.

Table 2 (Note) The strength retention rate is based on the same measurement method as in Table 1.

In addition, the liquid crystalline polyester resins A and B used.

C and D have the following structural units.

=60/20/20 〇－ The specific manufacturing methods of the resins A, B, C and D are described below.

Resin A> 1081 parts by weight of 4-acetoxybenzoic acid, 460 parts by weight of 6-acetoxy-2-naphthoic acid, 166 parts by weight of isophthalic acid
194 parts by weight of 1,4-diacetoxybenzene were charged into a reactor equipped with a stirrer, a nitrogen inlet tube and a distillation tube, and the mixture was heated to 260°C under a nitrogen stream.

2.5 at 260°C while distilling acetic acid from the reactor.
and then stirred vigorously at 280° C. for 3 hours.

Furthermore, after raising the temperature to 320°C and stopping the introduction of nitrogen, the pressure in the reactor was gradually reduced to 0 after 15 minutes.
．． The thickness was lowered to 1 mm and 11 g, and the mixture was stirred at this temperature and pressure for 1 hour.

The resulting polymer had an intrinsic viscosity of 5.0, measured in pentafluorophenol at a concentration of 0.1% by weight at 60°C.

Resin B> 1081 parts by weight of 4-acetoxybenzoic acid, 489 parts by weight of 2.6-diacedoxynaphthalene, 332 parts by weight of terephthalic acid
Parts by weight were charged into a reactor equipped with a stirrer, a nitrogen inlet tube and a distillation tube, and the mixture was heated to 250° C. under a nitrogen stream. 2 at 250°C while distilling acetic acid from the reactor.
and then stirred vigorously at 280° C. for 2.5 hours.

Furthermore, after raising the temperature to 320°C and stopping the introduction of nitrogen, the pressure inside the reactor was gradually reduced to 0.30 minutes later.
The temperature was lowered to 2 mmHg, and the mixture was stirred at this temperature and pressure for 1.5 hours.

The resulting polymer had an intrinsic viscosity of 2.5 as measured in pentafluorophenol at 60"C at a concentration of 0.1% by weight.

Resin C> 1261 parts by weight of 4-acetoxybenzoic acid and 691 parts by weight of 6-acetoxy-2-naphthoic acid were charged into a reactor equipped with a stirrer, a nitrogen introduction pipe and a distillation pipe, and the mixture was heated under a nitrogen stream. The mixture was heated to 250°C. 250°C for 3 hours, then 280°C while distilling acetic acid from the reactor.
The mixture was stirred vigorously for 2 hours. Further, the temperature was raised to 320°C, and after stopping the introduction of nitrogen, the pressure in the reactor was gradually reduced to 0.1 mmHg after 20 minutes, and stirring was continued at this temperature and pressure for 1 hour.

The resulting polymer had an intrinsic viscosity of 5.4, measured in pentafluorophenol at a concentration of 0.1% by weight at 60°C.

<Resin D> 1612 parts by weight of 6-acetoxy-2-naphthoic acid, 4-
290 parts by weight of acetoxyacetanilide, 249 parts by weight of terefucuric acid, and 0.4 parts by weight of sodium acetate in a stirrer,
The mixture was charged into a reactor equipped with a nitrogen inlet tube and a distillation tube, and heated to 250° C. under a nitrogen stream. While distilling acetic acid from the reactor, the temperature was 1 hour at 250°C, then at 300°C.
Stir vigorously for 3 hours at °C. Furthermore, the temperature was raised to 340°C, and after stopping the introduction of nitrogen, the pressure in the reactor was gradually reduced, and after 30 minutes, the pressure was lowered to 0.2 mm11 g.
The mixture was stirred at this temperature and pressure for 30 minutes.

The resulting polymer had an intrinsic viscosity of 3.9, measured in pentafluorophenol at a concentration of 0.1% by weight at 60°C.

Claims (1)

[Scope of Claims] 1. A racket string comprising a melt-processable polyester capable of forming an anisotropic melt phase. 2. The racket string according to claim 1, which is a fibrous material that has not been cold-stretched.