JPH0633525B2 - Method for spinning aromatic polyester - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for spinning aromatic polyester fibers having high strength and high elastic modulus.

(Prior Art) In recent years, it has become clear that aromatic polyesters having anisotropy when melted become fibers having high strength and high elastic modulus by melt spinning. It has various advantages such as not using a solvent and using a known spinning device. However, since the spinning temperature is higher than that of a normal polymer, decomposition or polymerization, a reaction such as crosslinking may occur during spinning, and foaming, increase in viscosity, etc.
There was an obstacle in performing stable spinning for a long time.

Although many patents on aromatic polyester fibers that exhibit anisotropy when melted have been reported (Japanese Patent Publication No. 55-482, etc.), they are mostly examples of small scales in the laboratory stage, and they are called stable spinning operations. It could not be a finding from a practical point of view.

(Problems to be Solved by the Invention) An object of the present invention is to remove impurities in a melt and to subdivide and orient polymer aggregates exhibiting anisotropy during melting to finally obtain high strength and high strength. An object of the present invention is to provide a method for industrially producing elastic modulus aromatic polyester fibers.

(Means for Solving Problems) An object of the present invention is to melt-spin an aromatic polyester exhibiting anisotropy when melted, which is composed of an inorganic fiber having a fiber diameter of 20 μm or less, and permeation of particles of 20 μm or more. Industrially advantageous is achieved by means of spinning after the material having a rate of 5% or less.

When the polyester sample powder is placed on a heating sample table between two polarizing plates that are orthogonal to each other at 90 ° to the polyester that exhibits anisotropy when melted in the present invention and the temperature is raised, the It means that it has a property of being capable of penetrating. Such an aromatic polyester is composed of an aromatic dicarboxylic acid, an aromatic diol and / or an aromatic hydroxycarboxylic acid shown in Japanese Patent Publication No. 56-18016 or 55-20008, or a derivative thereof,
In some cases, a copolymer of these with an alicyclic dicarboxylic acid, an alicyclic diol, an aliphatic diol, or a derivative thereof is also included.

Here, as the aromatic dicarboxylic acid, terephthalic acid, isophthalic acid, 4,4'-dicarboxydiphenyl, 2,6
-Dicarboxynaphthalene, 1,2-bis (4-carboxyphenoxy) ethane, and the like, and their alkyl, aryl, alkoxy, and nuclear substituents of halogen groups. As aromatic diols, hydroquinone, resorcin, 4,4'-dihydroxydiphenyl, 4,4'-dihydroxybenzophenone, 4,4'-dihydroxydiphenylmethane, 4,4'-dihydroxydiphenylethane, 2,2-bis (4 -Hydroxyphenyl) propane, 4,4'-dihydroxydiphenyl ether, 4,
4'-dihydroxydiphenyl sulfone, 4,4'-dihydroxydiphenyl sulfide, 2,6-dihydroxynaphthalene, 1,5-dihydroxynaphthalene and the like, and their alkyl, aryl, alkoxy and halogen-substituted nuclear groups are mentioned. As the aromatic hydroxycarboxylic acid, p-hydroxybenzoic acid, m-hydroxybenzoic acid, 2-hydroxynaphthalene-6-carboxylic acid, 1
-Hydroxynaphthalene-5-carboxylic acid and the like, and their alkyl, aryl, alkoxy, and nuclear substituents of halogen groups are mentioned.

Examples of the alicyclic dicarboxylic acid include trans-1,4-dicarboxycyclohexane, cis-1,4-dicarboxycyclohexane and the like, and their alkyl, aryl, and halogen group substitution products. Examples of the alicyclic and aliphatic diols include trans-1,4-dihydroxycyclohexane, cis-1,4-dihydroxycyclohexane, ethylene glycol, 1,4-butanediol and xylylenediol.

Among these combinations, the aromatic polyester preferable as the object of the present invention includes, for example, (1) p-hydroxybenzoic acid residue 40 to 70 mol%, the aromatic dicarboxylic acid residue 15 to 30 mol% and aromatic. A copolyester consisting of 15 to 30 mol% of a group diol residue, (2) a copolyester consisting of terephthalic acid and / or isophthalic acid and chlorohydroquinone, phenylhydroquinone and / or hydroquinone, (3) p-hydroxybenzoic acid residue 20 ~ 80 mol% and 2
-Hydroxynaphthalene-6-carboxylic acid residue 20 to 8
An example is a copolyester consisting of 0 mol%. In order to reach the polyester of the present invention using these starting materials, esterification with the aliphatic or aromatic monocarboxylic acid or a derivative thereof, an aliphatic alcohol or a phenol or a derivative thereof, etc. is carried out as it is. The polycondensation reaction is carried out. As the polycondensation reaction, known bulk polymerization, solution polymerization, suspension polymerization method or the like can be adopted.
Sb, Ti, Ge at 0 ℃ under normal pressure or 10 to 0.1 torr
Polymerization catalysts for compounds, stabilizers for phosphorus compounds, TiO ₂ , C
It can be carried out by adding a filler such as aCO ₃ or talc as the case may be. The obtained polymer is used as it is, or in the form of powder, which is heat-treated in an inert gas or under reduced pressure to prepare a spinning sample. Alternatively, it can be used by once granulating with an extruder. The aromatic polyester in the present invention is considered to have a molecular weight range suitable for spinning, but there is no solvent that can be uniformly dissolved depending on the composition or structure, or there is a problem that the accuracy of the molecular weight measurement method is not,
It cannot be used as a standard for aromatic polyesters suitable for the present invention. Therefore, the present inventors have introduced "flow temperature" as a physical property value corresponding to a molecular weight suitable for melt spinning conditions. Using a Shimadzu CFT-500 flow tester, a nozzle with a diameter of 1 mm and a length of 10 mm, pressure 100 kg / c
The "flow temperature" was defined as the temperature at which an aromatic polyester sample was heated at 4 ° C / min at m ² and the sample flowed through a nozzle and gave an apparent viscosity of 48,000 poise. The present inventors synthesized aromatic polyesters of various compositions and tried to change the flow temperature thereof. As a result, the flow temperature of the aromatic polyester suitable for the spinning of high-strength and high-elasticity fibers, which is the object of the present invention, was obtained. Was found to be 280-380 ° C. If the flow temperature is lower than this temperature range,
There is a problem that the reaction during melting tends to occur and the fiber elongation is difficult to come out.If it is high, the processing (spinning) temperature becomes high, so that decomposition and crosslinking reactions easily occur, and the load on the equipment becomes large. Cause

A known device can be used as the device for performing the melt spinning of the present invention. In the present invention, the temperature suitable for melt spinning is 2
The temperature is 80 to 420 ° C, preferably 300 to 400 ° C. When the temperature is lower than this temperature range, the load on the apparatus becomes large, and the uniform melting of the sample is insufficient. On the contrary, when the temperature is higher than this temperature range, yarn breakage due to decomposition and foaming may occur. Although it is melted in this temperature range, an important point in the present invention is to remove impurities and gel contained in the melt, to subdivide aggregates exhibiting anisotropy during melting, and to promote orientation. The purpose is to use a material composed of an inorganic fiber having a fiber diameter of 20 μm or less and having a transmittance of particles of 20 μm or more of 5% or less and passing the sample melt.

Aromatic polyester samples to be melt-spun include:
There are cases where foreign substances in the starting material, gels and foreign substances generated or mixed in during polymerization or post-treatment are included. These adversely affect spinning and cause problems such as nozzle hole blockage ejection failure and yarn breakage. Therefore, as described in the present invention,
However, since the object of the present invention is a fiber having a high strength and a high elastic modulus, the influence of minute impurities is large. Since it is desired that the finally obtained fiber diameter is 30 μm or less, the presence of foreign matter of 20 μm or more is fatal. As the material of the material, a sintered body of inorganic fiber such as stainless steel wire, other metal, or fiber made of inorganic material is preferable.
There is also a sintered body of inorganic particles as a material, but it is too effective.
It is better to use the sintered body of the inorganic fiber of the present invention as a material in terms of pressure resistance and the like. The diameter of the inorganic fiber of the material used in the present invention is 20 μm
The following is good. Although the detailed reason is unknown, it is likely that the aggregated state (flowable) that exhibits anisotropy when melted is subdivided in this fiber portion, making it easy for the molecules to be oriented, resulting in spinnability and fiber physical properties. It is thought that it may be effective for this, and this point is a point greatly different from ordinary melt spinning.

The materials described in the present invention have the effect that the aromatic polyester may be overtreated in advance before spinning. Also, when using a material coarser than the material recommended by the present invention at the tip of the extruder at the time of spinning, and removing larger contaminants, gels, etc., and then allowing the material of the present invention to pass, the operating time of the material is reduced. It could be long.

As the form of the material, a flat plate type, a candle type, a leaf disc type and the like can be adopted. The fibers spun according to the present invention can be left as they are, or they can be drawn down by winding with an oil agent attached. Winding or withdrawing speed is 10 to 10,0
Although it is 00m / min, it is 100 ~ in view of productivity and stable spinning.
2,000 m / min is preferred.

The thickness and cross-sectional shape of the obtained fiber are selected depending on the application, but a yarn diameter of 1 to 10 denier is preferable from the viewpoint of strength and elastic modulus. The obtained fiber can be used as it is, but by subjecting it to heat treatment, drawing or a combination thereof, it is possible to further increase the strength and elasticity.

(Function) A polymer aggregate which is capable of effectively removing gel and foreign matter that cause clogging of nozzle holes, ejection failure, yarn breakage, and the like and which is anisotropic when melted by means of passing with such a specific material It is considered that the material is subdivided when passing through the material, and the molecules are easily oriented, so that the spinnability and fiber physical properties are remarkably improved.

(Effects of the Invention) In this way, the impurities in the melt can be effectively removed, and the aromatic polymer having excellent physical properties can be obtained without problems in spinning operation based on the subdivision and the promotion of orientation of the anisotropic polymer aggregate. The fact that polyester fibers can be produced is a characteristic advantage of the present invention, and thus the fibers obtained by the present invention include tire cords, ropes, cables, FRP, FRTP, speaker cones,
It can be used for safety wear, tension members, etc.

(Examples) Examples and comparative examples are shown below for illustrating the present invention in detail, but these are merely examples and are not intended to be limiting.

In addition, the tensile test of the fiber in the example uses a universal testing machine No. 1130 manufactured by Instron Co., Ltd., with a sample interval of 20 mm and a tensile speed of 0.5 mm.
It was measured at / min.

The optical anisotropy was measured by placing the sample on a heating stage, heating it at 25 ° C./min under polarized light, and observing it with the naked eye.

Reference Example 1 p-acetoxybenzoic acid 7.20 kg (40 mol), terephthalic acid 2.49 kg (15 mol), isophthalic acid 0.83 kg (5 mol), 4,4'-diacetoxydiphenyl 5.45 kg (20.2
(Mol) was charged into a polymerization tank having a comb-type stirring blade, and the temperature was raised with stirring under a nitrogen gas atmosphere, and polymerization was carried out at 330 ° C. for 3 hours. During this period, acetic acid produced was removed, polymerization was carried out with vigorous stirring, and then gradually cooled and the polymer was taken out of the system at 200 ° C. The polymer yield is 10.88 kg, which is the theoretical yield of 97.
It was 8%. This was crushed with a hammer mill manufactured by Hosokawa Micron Co., Ltd. to obtain particles of 2.5 mm or less. When this was processed in a rotary kiln under a nitrogen atmosphere at 280 ° C. for 5 hours, the “flow temperature” was 330 ° C. Optical anisotropy was observed at 350 ° C or higher.

Reference Example 2 Using the same apparatus as in Reference Example 1, a polyester composed of 2,5-diacetoxybiphenyl and terephthalic acid was synthesized.

The “flow temperature” of this polyester is 317 ° C.
Optical anisotropy was observed at 40 ° C or higher.

Example 1 The aromatic polyester of Reference Example 1 was used, and spinning was performed using a screw type extruder having a diameter of 30 mm. Three 400-mesh wire nets are used in combination with a 200-mesh wire net at the screw head part, and a stainless steel wire sintering filter (Nassron filter NF-06 made by Nippon Seisen) is provided between the gap pump and the nozzle. It was This filter is obtained by laminating and sintering stainless steel wire having a diameter of 10 μm or less, and removes 95% or more of particles of 10 μm or more. When a nozzle having a hole diameter of 0.10 mm, a hole length of 0.8 mm and a number of holes of 200 was used and spun at a spinning temperature of 365 ° C., the yarn was stably spun for 2 hours (spinning speed 68
0m / min). When the obtained light yellow transparent fiber was heat-treated in nitrogen at 320 ° C. for 3 hours, the strength was 30.1 g / d, the strength dispersion was 10.4%, the elongation was 2.9%, and the elastic modulus was 1,050 g / d at 2.80 denier.

Comparative Example 1 The aromatic polyester of Reference Example 1 was used, and three 500-mesh plain weave wire nets were used instead of the sintered filter of the stainless wire of Example 1. The diameter of the wire used in this wire mesh is 26 μm. For reinforcement, a wire mesh of 200 mesh was put in between, and wire meshes of 100 mesh and 50 mesh were put on the lower side. Spinning was started at 365 ° C. in the same manner as in Example 1, but the winding speed could not be increased as compared with Example 1, and the maximum was 390 m / min. It is considered that the spinnability is inferior to that of Example 1 due to the presence of impurities in the molten dope and the presence of a macro-aggregated state. 320 this fiber
Treated in nitrogen for 3 hours at 5.12 denier, strength 22.3g / d, strength dispersion 12.1%, elongation 2.8%, elastic modulus 805g.
/ d, which was inferior to Example 1.

Example 2 Using the polyester of Reference Example 2, melt spinning was performed under the same conditions as in Example 1. However, the spinning temperature is 360 ° C. It was possible to stably wind at a winding speed of 520 m / min for 1 hour. When the obtained fiber is treated in nitrogen at 320 ° C for 3 hours, 3.83 denier, strength 23.8 g / d, strength dispersion 10.7
%, Elongation 3.2%, elastic modulus 751 g / d.

Comparative Example 2 Using the polyester of Reference Example 2, melt spinning was performed under the same conditions as in Comparative Example 1. However, the spinning temperature is 360 ° C.

As in Example 2, it could not be wound at 520 m / min, and the maximum was 310 m / min. Also, single yarn breakage was observed. This fiber was heat treated under the same conditions as in Example 2, but was found to have 6.45 denier, strength 14.0 g / d, strength dispersion 16.2%, elongation 2.8%,
The elastic modulus was 527 g / d, which was significantly inferior to that of Example 2.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Seiji Takao 3-3-1, Kanaokahigashi-cho, Okayama-shi, Okayama Nihon Exlan Industrial Co., Ltd. (56) References JP-A-54-138621 (JP, A) JP-A-57-41934 (JP, A) JP-A-58-45224 (JP, A) JP-A-58-149324 (JP, A) JP-A-58-149325 (JP, A) JP-A-59-1711 (JP, A) JP-A-59-1712 (JP, A)

Claims (1)

[Claims] 1. When melt-spinning an aromatic polyester exhibiting anisotropy when melted, it is made of inorganic fibers having a fiber diameter of 20 μm or less, and the transmittance of particles of 20 μm or more is 5%.
A method for spinning an aromatic polyester, which comprises spinning after filtering with the following filter medium.