JPS6042287B2 - Split fiber manufacturing method - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method for manufacturing split fibers.

More specifically, the present invention relates to a method for economically producing a polyester split fiber having a high Young's modulus. [Prior Art] Conventionally, methods for producing split fibers from films of synthetic polymers such as polyethylene terephthalate nylon-6, nylon-6, 6, etc. are well known (see, for example, Japanese Patent Publication No. 49-6771). .

However, it is difficult to split the films of these synthetic polymers, and therefore, for example, a) splitting is performed after forming a highly oriented film, or b) at room temperature or below, for example -20
c) forming filaments or films using blends with other synthetic polymers and then splitting them. However, the split fiber has a low Young's modulus, which limits its use. [Problems to be Solved by the Invention] The present inventors have arrived at the present invention as a result of repeated research on a method for efficiently producing a split fiber having a high Young's modulus.

That is, an object of the present invention is to provide a method for producing a split fiber having a significantly higher Young's modulus than the conventional method using only the forming and splitting steps. [Structure of the Invention] The present invention relates to an unstretched polyester molded product obtained by molding a melt mainly composed of polyester having the property of forming an anisotropic melt into a filament or film shape at a draft ratio of 1 or more. Young's modulus is 20, which is characterized by splitting things.
It is a split fiber manufacturing method with a rate of 9/1 or more.

In the present invention, the polyester having the property of forming an anisotropic melt refers to a polyester having the property of allowing the polymer in a molten state to pass polarized light in an optical system equipped with a 900 cross polarizer. .

Examples of such polyesters include the following.

[A] Terephthalic acid 9 diphenyl ether-4,4'
-dicarboxylic acid, diphenyl-4,4'-dicarboxylic acid, diphenooxyethane-4,4'-dicarboxylic acid, naphthalene-2,6-dicarboxylic acid, cyclohexane-1,
Symmetrical aromatic dicarboxylic acids or symmetrical alicyclic dicarboxylic acids such as 4-dicarboxylic acid: methylterephthalic acid, methoxyterephthalic acid, chlorterephthalic acid, bromoterephthalic acid, diphenyl ether-2,2-dimethyl-4,
4″-dicarboxylic acid, diphenoxyethane-2,2″
The main acid component is a lower alkyl, lower alkoxy or halogen substituted product of the symmetrical aromatic dicarboxylic acid or alicyclic dicarboxylic acid such as -dichloro-4,4''-dicarboxylic acid, cyclohexane-1-methyl-1,4-dicarboxylic acid, etc. , hydroxine, 4,4″-dioxydiphenyl, 4,4″-dioxydiphenyl ether,
Symmetrical dioxyaromatic compounds such as 2,6-dioxynaphthalene, 2,7-dioxynaphthalene, 4,4''-dioxydiphenoxyethane, etc.; chlorohydroquinone, bromohydroquinone, methylhydroquinone, ethylhydroquinone, 2,2″-dimethyl-4,4″-dioxydiphenyl, 3,3″-dimethoxy-4,4″-
Dioxydiphenyl ether, 2,2″dichloro-4,
Homopolyester or copolyester (hereinafter referred to as polyester A) containing a lower alkyl, lower alkoxy or halogen substituted product of the symmetrical dioxyaromatic compound such as 4''-dioxydiphenoxyethane as a main diol component.

[B] p-oxybenzoic acid, 4-oxydiphe 32-4'' monocarboxylic acid, 3-chloro-4-oxybenzoic acid,
3-methoxy-4-oxybenzoic acid, 2-methyl-4
Copolyesters containing aromatic oxycarboxylic acids such as -oxybenzoic acid, 2-chloro-4-oxydiphenyl-4'' monocarboxylic acids, and/or lower alkyl, lower alkoxy or halogen substituted products of these three as copolymerization components ( (hereinafter referred to as polyester B).As acid components that can be used in the production of polyesters A and B, in addition to the aromatic dicarboxylic acid and alicyclic dicarboxylic acid, isophthalic acid, diphenyl ether ,3
''-dicarboxylic acid, diphenyl-3,4'-dicarboxylic acid, diphenoxyethane-3,3''-dicarboxylic acid, naphthalene-1,6-dicarboxylic acid, m-oxybenzoic acid, cyclohexane-1,3-dicarboxylic acid , 5-methylisophthalic acid, 5-chloroisophthalic acid, 4-methylisophthalic acid, 5-tert-butyl isophthalic acid, diphenyl ether-4,4-dichloro-3,3''-dicarboxylic acid, diphenyl-3,4'- Dimethyl-4,3''-dicarboxylic acid, diphenooxyethane-2,2''-dibromo-3,3''-dicarboxylic acid, naphthalene-2,7-dichloro-1,6-dicarboxylic acid, 4-ethoxy-3-
Oxybenzoic acid, 4-methylcyclohexane-1,3-
Examples include aromatic dicarboxylic acids such as dicarboxylic acids, aromatic oxycarboxylic acids, alicyclic dicarboxylic acids, lower alkyl or halogen substituted products thereof, and carbonic acid. In addition to the dioxy aromatic compounds, examples of diol components that can be used in the production of polyesters A and B include resorcinol, 3,3''-dioxydiphenyl, 3,3''-dioxydiphenyl ether, 1,6 -Dioxynaphthalene, 3,3"-dioxydiphenooxyethane, 4-chlorresorcin, 4-ethoxyresorcin, 4-bromlesorcin, 4,4"-
Dimethoxy-3,3″-dioxydiphenyl,4,4
″-dimethyl-3,3″-dioxydiphenyl, 4,4
″-dimethoxy-3,3″-dioxydiphenyl ether, 2,4″-dichloro-3,3″-dioxydiphenyl ether, 2,5-dichloro-1,6-dioxynaphthalene, 2,2″-dibromo-3,3″-dioxydi, phenoxyethane, etc. aromatic dioxy compounds or lower alkyl, lower alkoxy or halogen substituted products thereof.

Polyesters suitable for use in the method of the invention include:
For example, p-oxybenzoic acid, terephthalic acid, isophthalic acid, diphenoxyethane-4,4''-dicarboxylic acid, diphenyl ether-4,4''-dicarboxylic acid,
naphthalene-2,6-dicarboxylic acid, naphthalene-2,7
- one or more dicarboxylic acids selected from the group consisting of dicarboxylic acid, cyclohexane-1,4-dicarboxylic acid and carbonic acid, and hydroquinone, chlorohydroquinone, methylhydroquinone, 4,4''-dioxydiphenyl and , 4''-dioxydiphenyl ether; b. Terephthalic acid, diphenyl ether, 4,4''-dicarboxylic acid, diphenyl-4, 4″-dicarboxylic acid, diphenoxyethane-4
, 4″-dicarboxylic acid, naphthalene-2,6-dicarboxylic acid, naphthalene-2,7-dicarboxylic acid, and cyclohexane-1,4-dicarboxylic acid, or one or more dicarboxylic acids selected from the group consisting of; Hydroquinone, chlorhydroquinone, methylhydroquinone, 4,
Homopolyester or copolyester consisting of one or more dioxyaromatic compounds selected from the group consisting of 4''-dioxydiphenyl and 4,4''-dioxydiphenyl enotel; c terephthalic acid, diphenyl-4 , 4″-dicarboxylic acid, diphenoxyethane-4,
One or more aromatic dicarboxylic acids selected from the group consisting of 4″-dicarboxylic acid, naphthalene-2,6-dicarboxylic acid, and naphthalene-2,7-dicarboxylic acid;
A copolymer consisting of carbonic acid and one or more dioxyaromatic compounds selected from the group consisting of hydroquinone, chlorohydroquinone, methylhydroquinone, 4,4''-dioxydiphenyl and 4,4''-dioxydiphenyl ether. Examples include polyester.

Among these, the following polyesters are particularly preferred.

Copolyester consisting of 1p-oxybenzoic acid and isophthalic acid and/or terephthalic acid and hydroquinone and/or 4,4''-dioxydiphenyl, 2p-oxybenzoic acid and diphenoxyethane-4,4-dicarboxylic acid A copolyester consisting of hydroquinone and/or chlorohydroquinone, a copolyester consisting of 3p-oxybenzoic acid, cyclohexane-1,4-dicarboxylic acid, hydroquinone and/or chlorohydroquinone, 4p-oxybenzoic acid, isophthalic acid, and carbonic acid. Copolyester consisting of hydroquinone, 5 Copolyester consisting of terephthalic acid, diphenooxyethane-4,4''-dicarboxylic acid and chlorohydroquinone, 6
Copolyester consisting of terephthalic acid and naphthalene-2,6-dicarboxylic acid and methylhydroquinone, 7
Copolyester of terephthalic acid, carbonic acid and hydroquinone, homopolyester of 8-cyclohexane-1,4-dicarboxylic acid and chlorohydroquinone.

The above-mentioned polyester can be produced by a method known per se.

For example, if necessary, a lower fatty acid ester of an aromatic dicarboxylic acid and/or an alicyclic dicarboxylic acid and a lower fatty acid ester of a dioxyaromatic compound (such as an acetate ester) may be combined with a lower fatty acid ester of an aromatic oxycarboxylic acid (such as an acetate ester). aryl ester of diaromatic dicarboxylic acid and/or aliphatic dicarboxylic acid (
For example, a phenyl ester, etc.) and a dioxyaromatic compound are heated and polymerized together with an aryl ester of an aromatic oxycarboxylic acid (for example, a phenyl ester, etc.) as necessary. 4 aliphatic dicarboxylic acid chloride and/or alicyclic dicarbonate, by reacting a dioxyaromatic compound with a diaryl carbonate such as diphenyl carbonate, optionally with an aromatic oxycarboxylic acid, and then heating and polymerizing the reaction mixture. A method is employed in which an acid chloride and a dioxyaromatic compound are polymerized together with an aromatic oxycarboxylic acid chloride, if necessary, in the presence or absence of an acid-removal agent.

In these production methods, inert compounds with high boiling points such as diphenyl, diphenyl ether, diphenooxybenzene, terphenyl, alkylnaphthalenes such as methylnaphthalene, ethylnaphthalene, partially hydrogenated products of terphenyl, etc. may coexist in the reaction system.

The above-mentioned polyester used in the method of the invention is a polymer having film-forming or fiber-forming ability.

According to the method of the present invention, the above-mentioned polyester is melt-molded into a filament or film, and the resulting unstretched filament or unstretched film is subjected to a splitting process to split the fibers. Manufactured.

Melt molding of polyester is, for example, 240 to 4500
C. Preferably, it can be carried out by melt extruding the polyester at a temperature of 260 to 400C.

In melt molding, various known molding devices can be used for molding. The draft rate during extrusion molding is
It is necessary to set it as 1 or more, and preferably it is 1-20. If a molded product is extruded with a draft ratio of less than 1, the resulting split fiber will not have sufficient strength or Young's modulus, and if the molded product is split using various methods described below to produce split fibers. This is not preferable because splitting is not only difficult, but also the shape and size of the split fibers tend to vary widely.
The above-mentioned polyester molded product thus obtained can be easily split, unlike conventional polyester molded products such as polyethylene terephthalate molded products, without being subjected to stretching treatment. Specifically, the splitting methods include 1) a hammering method in which a certain amount of tension is applied to the molded product and then an impactful stiffness is applied to it, and 2) a kneading method in which force is applied at right angles to the orientation direction of the molded product. , 3) Made with a comb roller.
The brushing method of combing the shape, 4) the method of splitting the molded product by exposing it to a high-speed air stream, and 5) the cutting method of cutting the molded product into fibers using a sharp knife, etc. can.

In the method of the present invention, polyester molded or! The split fibers produced by opening the molded product are heated in an appropriate temperature range (below the flow start temperature) as necessary.
For example, the strength of the split fiber can be increased by heat-treating the split fiber at a temperature of 250 to 350 DEG C. according to a method conventionally known as a heat treatment method for this type of polyester. [Effects of the Invention] The method of the present invention as described above has a higher Young's modulus (i.e., 2000k9/Tn!t or more) than conventional polyester.
The advantage is that split fibers can be easily obtained.
This split fiber is used for applications that require a high Young's modulus, such as rubber reinforcement for tires, hoses, belts, etc.
It is also useful as a fiber for reinforcing plastics.

Moreover, since the method of the present invention does not require a stretching step,
Production costs will be reduced accordingly.

[Examples] The present invention will be explained below with reference to Examples, but the present invention is of course not limited to these.

Example 1 p-oxybenzoic acid component: 60 mol%, isophthalic acid component: 40 mol%, hydroquinone component: 30 mol%, bisphenol A component: 10 mol%, intrinsic viscosity 0.87 (however, polymer 0.05g
was dissolved in 10 cc (7) p-chlorophenol, and 50
When the copolyester (measured at 350°C) was placed on the sample stage of a polarizing microscope equipped with a heating cell and the melting state at 350°C was observed, the field of view was bright even under crossed nicol conditions, indicating optical anisotropy. It was recognized that the

Next, the same polyester was heated and melted at 350'C and extruded through a slit die with a width of 5 mm and a thickness of 0.15 mm at a linear speed of 207 T1. /Min into air at room temperature and passed through a cooling drum at a linear velocity of 35rn. /Min
I wound it onto a bobbin (draft 1.75).

Next, this film-shaped molded product is pulled under constant tension)
The fibers were split using a brushing roller equipped with a large number of needles to obtain a split fiber bundle with an average single yarn fineness of 18 de. The average strength of this split fiber is 7.0y
/Del average Young's modulus is 2100kg/T! It was Ui. Comparative Example 1 p-oxybenzoic acid component: 60 mol%, isophthalic acid component: 40 mol%, hydroquinone component: 8 mol%, bisphenol A component: 32 mol%, intrinsic viscosity 0.85 (but polymer 0.05y
was dissolved in 10 cc (7) p-chlorophenol and heated at 50°C.
When heated to 340° C. or higher, the copolyester with a value determined by measurement at 340° C. became a uniform isotropic melt, and showed only a dark field under crossed nicol conditions.

This copolyester was extruded and solidified at 345° C. under the same conditions as in Example 1, and an attempt was made to split the fibers, but the fibers did not split easily and the average strength was about 1.5 y/De.
The average Young's modulus remained at an extremely low value of 320k9/Tnlt. Example 2 Consists of p-oxybenzoic acid component: 75 mol%, isophthalic acid component: 25 mol%, and 4,4''-dioxydiphenyl component: 25 mol%, and has an intrinsic viscosity of 0.95 (however, the polymer has a 0.05y A polyester that is optically anisotropic when melted and has a value obtained by dissolving 10 cc (7) in p-chlorophenol and measuring it at 50 °C is heated to 290 °C and melted to form a polyester with a width of 2'' and a thickness of 0.1. ? through a slit die and extrude vertically downward at a linear speed of 20 m./Mln, about 6
After passing through an air layer of
T1. / Min was wound on the drum (draft 2.25
).

Next, this film-like molded product was fed at a feed rate of 20Tr1.
Two rotating bodies having the same diameter and rotating in different directions at /Min were passed through an engagement surface formed by facing each other to form a split.

The single filament fineness of the obtained fibrillated split fibers is 10 to 20c1e, and the average strength is 8g/D.
e, the average Young's modulus was 2330k9/d. In addition, when a small amount of the copolyester was placed on the sample stage of a polarizing microscope equipped with a heating cell and the melting state at 290°C was observed, the field of view was bright even under crossed Nicol conditions, and it was confirmed that it had optical anisotropy. It was done. Example 3 Consists of p-oxybenzoic acid component: 60 mol%, diphenoxyethane-4,4''-dicarboxylic acid component: 40 mol%, hydroquinone component: 40 mol%, intrinsic viscosity 1.8
5 (value determined by dissolving 0.05q of polymer in 10 cc (7) p-chlorophenol and measuring at 50°C) was heated and melted at 310°C, and Example It was extruded through the same slit die as in 1 and taken off with a draft of about 3.0 to obtain a film-like molded product.

Next, this film-like material is split with a heater while being continuously moved between a pair of rollers, and the average single yarn fineness is about 9c.
A 1e split fiber bundle was obtained.

The average strength of this split fiber is 10y/Del
The average Young's modulus was extremely high at 2740 kg/Tnit. Comparative Example 2 The same copolyester as in Example 3 was also used at 310
Extrusion was carried out in the same manner as in Example 3 at ℃, with a draft of about 0.7
It was taken up by a cooling roll.

Subsequently, the film was stretched by about 1.5 times by passing it through a roll having a higher surface speed, and then wound onto a bobbin. Next, when this film-like material was beaten with a heater, fibers of sufficient length were not obtained, but instead only short bulb-shaped particles were obtained.

Example 4 Terephthalic acid component: 70 mol%, naphthalene-2,6-
Consists of dicarboxylic acid component: 30 mol% and methylhydroquinone component: 100 mol%, and has an intrinsic viscosity of 3.01 (
0.05y of polymer was dissolved in 10cc of p-chlorophenol and measured at 50°C).
When it was melted at 95°C and optical anisotropy was observed at a high temperature around this temperature in the same manner as in Example 1, optical anisotropy was observed.

This copolyester was heated to 3000C and melted to create a width of 20mm.
TWL, thickness 0.1? Extrusion through a slit die at a linear speed of 10 TI. /Mjnl into air at room temperature and passed through a cooling drum to 287T! ．． I wound it onto a bobbin at /Min (draft 2.8). Next, while applying tension to this film-like molded product, the fibers were split using a brushing roller equipped with a large number of needles to obtain a split fiber bundle having an average single fiber fineness of 22 de.

The average strength of this split fiber is 7.5y/De
The average Young's modulus was 2510k9/d. Example 5 Consists of p-oxybenzoic acid component: 67 mol%, isophthalic acid component: 28 mol%, carbonic acid component: 5 mol%, and hydroquinone component: 33 mol%, and has an intrinsic viscosity of 1.50 (polymer 0.05y). A copolyester having 10 cc of 2,4,6-trichlorophenol/2,4,5-trichlorophenol/2,4,5-trichlorophenol/2,4,5-trichlorophenol mixed solvent (weight ratio 50:50, measured at 35°C) was heated to 3400°C and melted. 0.5WL, extrusion through a die with 1 hole at a linear speed of 5m/M
It was extruded at a linear speed of 85 m/min and rolled up at a linear speed of 85 m/min (
Draft 17).

Next, while applying tension to this strand, it was passed through an engaging surface consisting of a pair of rotating bodies similar to the device of Example 2, split by contact pressure, and then led to a false twisting device. After that, I rolled it up.

The obtained yarn had an average strength of 7 q/De and an average Young's modulus of 2,550 kg/d, and was suitable as a reinforcing material for rubber belts, hoses, etc. The copolyester exhibited clear optical anisotropy at 340°C. Example 6 p-oxybenzoic acid component: 50 mol%, transcyclohexane-1,4-dicarboxylic acid component: 50 mol%,
and chlorohydroquinone component: 50 mol%,
Intrinsic viscosity 3.02 (polymer 0.05q 10cc (7
) dissolved in p-chlorophenol and measured at 505C) exhibits optical anisotropy when heated and melted at 340°C.

Claims (1)

[Claims] 1. It is characterized by splitting an unstretched polyester molded product obtained by forming a melt mainly composed of polyester having the property of forming an anisotropic melt into a filament or film shape at a draft ratio of 1 or more. Young's modulus is 200
A method for producing split fibers with a weight of 0 kg/mm^2 or more.