JPH0314620A - Wholly aromatic polyester fiber - Google Patents

Abstract

PURPOSE:To obtain the subject fiber suitable for industrial filter, etc., having excellent heat resistance, chemical resistance and fiber properties comprising wholly aromatic polyester having respectively specific four types of repeating units and transferring from crystalline state to optically isotropic melt with melting. CONSTITUTION:Isophthalic acid (derivative) is subjected to melt polymerization with p-hydroxybenzoic acid (derivative), hydroquinone (derivative) and aromatic bifunctional phenol (derivative) to obtain a wholly aromatic polyester having repeating units expressed by formula I-formula IV (Ar is 1,3-phenylene, etc.), <=335 deg.C melting point and from 50 poise to 10X10<4> poise melt viscosity and transferring from crystalline state to optically isotropic melt with melting. Then, said wholly aromatic polyester is subjected to melt spinning and preferably drawn at >=1.05 times to afford the objective fiber having >=1.5g/d strength, >=5% elongation and <=7% shrinkage at 160 deg.C.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a wholly aromatic polyester fiber having excellent heat resistance, chemical resistance, and fiber performance. More specifically, the present invention is a wholly aromatic fiber spun from an isotropic melt of a crystalline polymer with a high glass transition point, which has a low shrinkage rate at high temperatures, does not cause problems such as fibrillation, and is useful for industrial filters. This relates to polyester SaW.
Furthermore, the fibers are useful as matrix fibers for composite materials with carbon, SaW, etc. (Conventional technology) In recent years, there has been an increasing demand for fibers with excellent heat and chemical resistance, such as fibers for industrial filters to save energy and fibers for matrices of high-performance composite materials. Several heat-resistant fibers have been developed to meet this requirement. For example, poly(P-phenylene sulfide) (PPS) fiber, aromatic polyamide fiber, poly(ether ether ketone)
(PEE II) fibers and wholly aromatic polyester fibers are known. However, pps woven fibers have a low glass transition point of 100°C or less, and have some problems with heat resistance. Also, pps is easy to crosslink,
It also has the disadvantage of being inferior in toughness as a matrix for composite materials.・Aromatic boria ξ-do fibers are produced by solution spinning, so it is difficult to produce a wide variety of fibers at low cost, and because they do not melt, they cannot be used as matrix fibers for composite materials. has, Pl! EK fibers have good heat resistance and can be manufactured by melt spinning, but the problem is that the raw material polymer is very expensive. Currently, the only known crystalline wholly aromatic polyester is molten liquid crystalline wholly aromatic polyester, and there is a problem in that the fibers obtained from it undergo fibrillation during use. Furthermore, when used as a matrix for composite materials, the physical properties exhibit anisotropy, which poses a practical problem. In other words, currently no fibers with a good balance of heat resistance, chemical resistance, and price have been developed.
(Problem B to be Solved by the Invention) The present inventors conducted research focusing on wholly aromatic polyester, which is known to be relatively inexpensive and to have excellent heat resistance and chemical resistance. At present, only molten liquid crystalline or non-quality wholly aromatic polyesters are known, and molten liquid crystalline wholly aromatic polyester 1C undergoes fibrillation as described above, and is also used as a matrix for composite materials. In this case, the anisotropy of the physical properties of the Kai-shaped product becomes a problem. On the other hand, non-grade wholly aromatic polyester has a heat deformation temperature of glass transition temperature and a heat resistance (
Especially in the case of composite materials), the polymer could not be stretched, and there were problems with fiber properties. (Means for Solving the Problems) The present inventors continued intensive research to obtain a crystalline wholly aromatic polyester that does not exhibit liquid crystallinity, and as a result, they discovered and proposed this wholly aromatic polyester. Furthermore, in order to solve the above-mentioned problems, the present inventors investigated the fiberization of such polymers, and as a result, they finally completed the present invention. That is, the present invention provides (1) the following general formula (
1) to (IV) are repeating units, and the melting point is approximately 335°C
Hereinafter, a wholly aromatic polyester having a melt viscosity of 50 poise to 100,000 poise and changing from a crystalline state to an optically isotropic melt upon melting, and a strength of 1.5 g/d or more;
A wholly aromatic polyester fiber with an elongation of 5% or more and a shrinkage rate at 160°C of 7% or less. (However, ^
r is a 1.3-phenylene group, a 1.2-phenylene group,
2-methyl-1,3-phenylene group, 5-methyl=■,
3-phenylene group, 4l4゜-biphenylene group, isopropylidene-4,4゜-diphenylene group, methylene 4,
4゜-diphenylene group, 1,1-butylidene-4,4゛-diphenylene group, thio 4,4'-diphenylene group,
Carbonyl represents a 4,4'-diphenylene group, a 2,6-naphthylene group, and a 2,7-naphthylene group. ) The present invention will be explained in more detail below.

The wholly aromatic polyester in the present invention is a derivative of p-hydroxybenzoic acid (V), hydroquinone and/or its derivative (Vl), and an aromatic dihydric phenol and/or its derivative (■) represented by the following general formula. and isophthalic acid and/or its derivative (■) until the melt viscosity of the polymer reaches 50 to 100,000 poise. RsO Ar ORi (■) In the above formula ^' is 1,3-phenylene group, 1,2-phenylene group, 2-methyl-1,3-phenylene group, 5-methyl-
1.3-phenylene group, 4.4'-biphenylene group, isobropylidene-4.4''-diphenylene group, methylene-4.4''-diphenylene group, 1.1-butylidene-4
．． 4゜-diphenylene group, thio-4.4゜-diphenylene group, carbonyl-4.4'-diphenylene group, 2.6
- Naphthylene group, 2,7-naphthylene group. Also h
is a hydrogen atom, a lower alkanoyl group having 7 or less carbon atoms,
selected from the group consisting of benzoyl groups, R is a hydrogen atom or an aryl group having 6 to 12 carbon atoms, and R, to R.
are each a hydrogen atom, a lower alkanoyl group having 7 or less carbon atoms, or a benzoyl group, and R and R are each selected from a hydrogen atom or an aryl group having 6 to 12 carbon atoms. Specific examples of the compounds represented by the general formulas (V) to (■) are p-formyloxybenzoic acid, p-acetoxybenzoic acid, p-propionyloxybenzoic acid, P-penzoyloxybenzoic acid, p- Phenyl hydroxybenzoate, tolyl p-hydroxybenzoate, p-butylphenyl p-hydroxybenzoate, p-hydroxybenzoic acid 2
-Naphthyl, hydroquinone, 1,4-diacetoxybenzene, 1,4-dipropionoyloxybenzene, 1.4
-dibenzoyloxybenzene, resorcinol, 1.3-
Diacetoxybenzene, 1.3-dipropionoyloxybenzene, 1.3-cybenzoyloxybenzene, pyrocatechol, 1.2-diacetoxybenzene, 1.2-
Diprobionoyloxybenzene, 1,2-dibenzoyloxybenzene, 2-methyl-1,3-benzenediol, 1,3-diacetoxy-2-methylbenzene, 1.
3-dipropionoyloxy-2-methylbenzene, 1.
3-dibenzoyloxy-2-methylbenzene, 5-methyl-1,3-benzenediol, 1,3-diacetoxy-5-methylbenzene, 1,3-dibropionoyloxy-5-methylbenzene, l, 3-dibenzoyloxy-5-methylbenzene, 4.4''-dihydroxybiphenyl, 4,4゜-diacetoxybiphenyl, 4,4゜-
Dibrobionoyloxybiphenyl, 4.4'-dibenzoyloxybiphenyl, 2.2-bis(4-hydroxyphenyl)propane, 2.2-bis(4-acetoxyphenyl)propane, 2.2-bis(4 monopropionoyloxyphenyl)propane, 2,2-bis(4-penzoyloxyphenyl)propane, bis(4-hydroxyphenyl)methane, bis(4-acetoxyphenyl)methane, bis(4-proionoyloxy phenyl)methane,
1.1-bis(4-hydroxyphenyl)butane, 1.
1-bis(4-acetoxyphenyl)butane, bis(4
-hydroxyphenyl) sulfide, bis(4-acetoxyphenyl) sulfide, bis(4-proionoyloxyphenyl) sulfide, bis(4-hydroxyphenyl) ketone, bis(4-acetoxyphenyl) ketone, bis( 4-proionoyloxyphenyl)ketone, 2
．． 6-dihydroxynaphthalene, 2.6-diacetoxynaphthalene, 2.7-dihydroxynaphthalene, 2.7
- diacetoxynaphthalene isophthalic acid, diphenyl isophthalate, isophthalic acid, diphenyl isophthalate,
Examples include ditolyl isophthalate and dip-p-chlorophenyl isophthalate. The characteristic melting point of the wholly aromatic polyester of the present invention and the optically isotropic melt form from the crystalline state due to melting can be obtained by appropriate combinations of the above-mentioned structural units (I) to (■). However, it was manufactured using a special polymerization method,
For example, polymers that exhibit melt liquid crystallinity by incorporating the structural unit (1) in block form into the main chain of the polymer are omitted from the present invention. The wholly aromatic polyester of the present invention is synthesized by a melt polymerization method using the monomers (V) to (■) above. At this time, a polymerization catalyst and various additives, such as stabilizers such as antioxidants and enhancers such as titanium oxide, may be added. If sufficient viscosity is required, it is also possible to increase the viscosity by solid phase polymerization after melt polymerization. The undrawn yarn in the present invention can be obtained by a conventional melt spinning method. In other words, it is a method in which a polymer melted using a melt extruder is extruded into fibers through a nozzle suitable for the purpose, and then rolled up while being cooled. There are no particular restrictions on the shape of the nozzle, and it is sufficient to use one that suits the purpose. When used as a matrix for composite materials, the obtained undrawn yarn can be used as is, but when used in applications such as filters, it is preferable to stretch it. One of the characteristics of the wholly aromatic polyester fiber of the present invention is that
It is possible to stretch the fiber by at least 1.05 times after melt spinning, and this feature is not found in currently known wholly aromatic polyester fibers. When stretching, the stretching temperature is below the glass transition point of the polymer.
30'C) or higher is preferable. Stretching at a temperature below this temperature is not preferable, as it may not be possible to draw the film sufficiently or problems such as whitening of the fibers may occur. The stretching ratio is preferably 1.05 times or more. The preferred stretching ratio is 1.1 times to 10 times. However, if the tension during spinning is large and the fiber is actually stretched during winding, the magnification must be considered.
Furthermore, when the obtained undrawn yarn or drawn yarn is heat-treated under constant length or tension at a temperature at or above the drawing temperature, the shrinkage rate at high temperatures is further reduced, and an industrially useful fiber can be obtained. The birch spinning, stretching, and heat treatment may be performed continuously or may be performed separately. It can be stretched after melt spinning as in the present invention, has heat resistance,
Fibers made of wholly aromatic polyester, which have excellent chemical resistance and fiber properties, and which do not undergo fibrillation during use, have not been previously known, and are completely new fibers. (Examples) The effects of the present invention will be specifically explained below using Examples, but the present invention is not limited by these. Prior to the examples, the measurement method used in the present invention will be explained. Melt viscosity: 50 lCg/by using a flow tester CFT type manufactured by Shimadzu Corporation using a nozzle with a diameter of 1 m and a length of 10 m.
The viscosity of the melt fluid when measured at 350°C under a pressure of d was defined as the melt viscosity. Melting point: Using a glass melting point measuring device manufactured by Yanagimoto Seisakusho, a sample sandwiched between two glass plates was heated at a rate of 7°C/min, and the melting point was defined as the temperature at which the polymer began to flow when light pressure was applied. Glass transition point: PerkinElmer DSC-7 type (
Perk in El-er 7 Serie
s Thermal Analysis System
s+) at a heating rate of 20°C/min under an argon atmosphere. Optical properties: Using the same equipment as used for melting point measurement, measurements were made by observing the brightness and darkness of the field of view under crossed Nicol conditions, with pressure applied to the sample sandwiched between two glass plates, and in a fluid state. If it becomes a dark field, it is an optically isotropic melt, and if it becomes a bright field, it is a liquid crystalline melt.

Crystallinity: Evaluated by powder X41 diffraction using a Rigaku Geigerflex with Cuka as the target and Ni as the filter. Fiber strength and elongation: Toyo Sokki universal tensile tester Tensilon t
Using lTM-3 type, sample length 5C11, pulling speed 5
Measured in Cll/min. Dry heat shrinkage rate: Sample length 3, OcI1 was taken and treated in hot air at 160°C for 1 hour, and is shown as the rate of change with respect to the original dimension.

Reference Example 1 54.04 g (0.300 mol) of P-acetoxybenzoic acid and 118.14 g of 1.4-diacetoxybenzene were placed in a reactor equipped with a stirrer, a cooling tube, and a nitrogen introduction tube.
g (0.608 mol), 1,3-diacetoxybenzene 5.90 g (0.030 mol), isophthalic acid 1
01.18 g (0.609 mol), 100 μg of magnesium acetate, and 400 μg of acetic acid were heated in a nitrogen atmosphere at a temperature increase rate of 1″C/min to 250°C to remove the acetic acid produced by the reaction. After reacting at 250°C for 0 minutes, 260 μ of triphenyl phosphate was added, and then 15
The reaction continued for several minutes. The resulting reaction mixture was taken out and ground and used in the next polycondensation reaction. A stirrer and a nitrogen inlet tube were installed, and the powder reaction mixture was introduced into the reactor maintained at 300'C, and the temperature was gradually increased to 330'C. From this point, depressurization was started and the pressure was reduced in 40 minutes. was set to 0.5 mHg.The temperature was further raised to 350°C and the reaction was continued for 10 minutes.The melting point of the obtained polymer was 310°C, the glass transition point was 165°C,
The melt viscosity was 940 poise. Powder X-ray diffraction showed that this polymer was crystalline, and upon melting, it changed from a crystalline state to an optically isotropic melt. The obtained polymer is referred to as Polymer A. Reference Example 2 Same as Reference Example 1 except that 9.37 g (0.030 mol) of 2.2-bis(4-acetoxyphenyl)propane was used instead of 1.3-diacetoxybenzene. A crystalline polymer having a melting point of 312°C and a glass transition point of 157°C and exhibiting an optically isotropic melt was obtained. This polymer is called Polymer B. Reference Example 3 In Reference Example 1, 8.11 g of 4,4'-diacetoxybiphenyl (
A crystalline polymer exhibiting an optically isotropic melt with a melting point of 330°C and a glass transition point of 172°C was obtained in exactly the same manner as in Example 1, except that 0.030 mol) was used. This polymer is referred to as Polymer C. Comparative Reference Example 1 In Reference Example 1, p-acetoxybenzoic acid 89.72
g (0.498 mol), 106.42 g (0.548 mol) of 1,4-diacetoxybenzene and 4
．． 4”-diacetoxybiphenyl 24.60 g (0
．． A polymer having a melting point of 328°C and a glass transition point of 174°C was obtained in exactly the same manner as in Example 1, except that 099 mol) was used. The polymer exhibited molten liquid crystallinity. This polymer is called Polymer D. Example 1 Each of the polymers obtained in Reference Examples 1 to 3 was extruded into filaments using a plunger-type tabletop spinner at a cylinder temperature of 370°C and a discharge rate of 0.5 g/min. The nozzle has a hole diameter of 0.5am and a hole length of 1. I used one from Omm. The filament was wound at a speed of 100 m+/min to obtain an undrawn yarn. Table 1 shows the quality of the undrawn yarn obtained. The elongation of the undrawn yarn obtained from Polymer D was approximately 2%, and fibrils were generated on the surface when it was bent by hand. Example 2 Each undrawn yarn obtained in Example 1 was drawn at a slit heater temperature of 150°C using a device equipped with a hot roller, a slit heater, and a winding roller. The quality of the drawn yarn obtained is shown in Table 2. Note that the drawn yarn obtained from Polymer D could not be drawn. Example 3 Each of the drawn yarns obtained in Example 2 was heat-treated at 200'C using a slit heater under a constant length. Table 3 shows the yarn quality of the heat-treated drawn yarn. Table 1: Quality of undrawn yarn Table 2: Quality of drawn yarn This will greatly contribute to the industry.

Claims (1)

[Claims] (1) The following general formulas (I) to (IV) are used as repeating units, the melting point is approximately 335°C or less, and the melt viscosity is 50 poise to 10
made of a wholly aromatic polyester that has a strength of 1.5 g/d or more, an elongation of 5% or more, and a shrinkage rate of 7% at 160°C. A wholly aromatic polyester fiber that is: ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(II) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(III) ▲There are mathematical formulas, chemical formulas, tables, etc.▼( IV) (However, Ar is a 1,3-phenylene group, 1,2-phenylene group, 2-methyl-1,3-phenylene group, 5-methyl-1,3-phenylene group, 4,4'-piphenylene group) , isopropylidene-4,4'-diphenylene group, methylene-4,4'-diphenylene group, 1,1-butylidene-4,4'-diphenylene group, thio-4,4'-diphenylene group, carbonyl-4, 4'-diphenylene group, 2
, 6, a naphthylene group, and a 2,7-naphthylene group. )