JPS61186516A - Spinning of aromatic polyester fiber - Google Patents

Abstract

PURPOSE:A melt-spinning unit in which its polymer pathes are filled with meltal or ceramic is used to effect melt-spinning of a specific polyester whereby the residence time of the polymer is controlled to produce polyester fiber of high strength and high elasticity. CONSTITUTION:The inside of the polymer paths in the melt-spinning unit is filled with granules of a metal such as gold or silver or ceramic such as alumina or zirconia, then an aromatic polyester which shows optical anisotropy, when melted and has a flowing temperature of 280-380 deg.C is melt-extruded through the above-stated unit so that the residence time of the polymer in the unit is controlled less than 30min, preferably for 2-20min to prevent the melted polymer from bubbling and deteriorating and give aromatic polyester fiber of high strength and elasticity with improved operation stability.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for melt spinning aromatic polyester fibers having high strength and high modulus of elasticity.

(Prior art) Aromatic polyamides (Japanese Patent Publication No. 47-2489, etc.) are famous as organic fibers with high strength and high modulus of elasticity, and are beginning to be used for various purposes. Since sulfuric acid solution is used for spinning, there are problems with coating, by-products, etc.

In recent years, it has become clear that fibers with high strength and high modulus of elasticity can be obtained by melt-spinning aromatic polyesters that exhibit optical anisotropy when melted. This technology is superior to aromatic polyamides in that it does not use solvents and in terms of equipment, but on the other hand, viscosity changes are highly dependent on temperature, and the spinning temperature is close to the decomposition temperature of the polymer, so it may decompose during melt spinning. It exhibits behavior different from conventional polymers in that it involves foaming due to reactions such as polymerization and crosslinking, and in particular, foaming makes the polymer composition non-uniform, mechanical action reduces spinnability, and denatured polymers No means have yet been found to solve the problems of deterioration of fiber properties and non-uniformity due to contamination.

(Problems to be Solved by the Invention) An object of the present invention is to solve the above-mentioned problems and to provide an aromatic ester that exhibits optical anisotropy when melted by foaming the melt.
In addition to preventing metamorphosis, etc., and providing good operational stability, it is melt-proof.
Finally, it is an object of the present invention to provide a means for producing fibers with excellent physical properties and uniformity in an industrially advantageous manner.

(Means for Solving the 8 Problems) An object of the present invention is to provide an aromatic polyester that exhibits optical anisotropy when melted and has a flow temperature of 280 to 880°C in a flow path of a melt spinning device using a metal or ceramic material. This can be achieved industrially advantageously by means of melt-spinning by controlling the residence time of the aromatic polyester melt in the flow path to 80 minutes or less by filling the aromatic polyester granules.

The present invention will be described in detail below, but first, the aromatic polyester that exhibits optical anisotropy when melted in the present invention is a polyester sample powder placed on a heated sample stand between two polarizing plates crossed at 90 degrees. A substance that has the property of being able to transmit light in the temperature range where it can flow when the temperature is increased.

Such aromatic polyester
Consisting of aromatic dicarboxylic acids, aromatic diols and/or aromatic hydroxycarboxylic acids shown in Japanese Patent Publication No. 16, No. 55-20008, etc., and derivatives thereof, in some cases, ring dicarboxylic acids, ring diols, etc. ,
Copolymers with aliphatic diols and derivatives thereof are also included. Here, the aromatic dicarboxylic acids include terephthalic acid,
Isophthalic acid, 4,4゛-dicarboxydiphenyl, 2
．． 6-dicarboxynaphthalene, 1,2-bis(4-carboxyphenoxy)ethane, etc., and their alkyls,
Nuclear substitution products of aryl, alkoxy, and halogen groups can be mentioned. Aromatic diols include hydroquinone, resorcinol, 4.4″-dihydroxydiphenyl, 4.4′
-dihydroxybenzophenone, 4,4'-dihydroxydiphenylmethane, 4,4'-dihydroxydiphenylethane, 2,2-bis(4-hydroxyphenyl)propane, 4,4'-dihydroxydiphenyl ether, 4,4' -dihydroxyphenylsulfone, 4.
Examples of the aromatic hydroxycarboxylic acids include 4'-dihydroxydiphenyl sulfide, 2.6-dihydroxynaphthalene, 1.5-dihydroxynaphthalene, etc., and their alkyl, aryl, alkoxy, and halogen-substituted products. Examples of aromatic hydroxycarboxylic acids include p- Examples include hydroxybenzoic acid, m-hydroxybenzoic acid, 2-hydroxynaphthalene-6-carboxylic acid, 1-hydroxynaphthalene-5-carboxylic acid, and nuclear substituted products of these alkyl, aryl, alkoxy, and halogen groups. . Examples of ring group dicarboxylic acids include trans-1,4-dicarboxycyclohexane, cis-1,4-dicarboxycyclohexane, and substituted products of these with alkyl, aryl, and halogen groups; ring group and aliphatic diols include trans
-1,4-dihydroxycyclohexane, cis-1
, 4-dihydroxycyclohexane, ethylene glycol, 1,4-butanediol, xylylene diol and the like.

Particularly preferable aromatic polyesters among these combinations include, for example, (1) 40 to 70 mol% of p-hydroxybenzoic acid residues, 15 to 80 mol% of the above aromatic dicarboxylic acid residues, and aromatic diol residues; (2) a copolyester consisting of terephthalic acid and/or isophthalic acid and chlorohydroquinone, phenylhydroquinone and/or hydroquinone, and (ω) 20-80 mol% of p-hydroxybenzoic acid residues; and 2-hydroxy-naphthalene-6-carboxylic acid residue 20
Examples include copolyesters comprising up to 80 mol%.

These starting materials can be used as they are, or by esterification with aliphatic or aromatic monocarboxylic acids or derivatives thereof, aliphatic alcohols, phenols, or derivatives thereof. Known bulk polymerization, solution polymerization, suspension polymerization, etc. can be adopted as the single polycondensation reaction method for carrying out the polycondensation reaction.
Under reduced pressure of l torr, polymerization catalysts such as Ti and Ge compounds, stabilizers such as phosphorus compounds, TiO2
, Caω8. This can be carried out by adding a filler such as talc if necessary. The obtained polymer is used as it is or in powder form and heat-treated in an inert gas or under reduced pressure to prepare a sample for spinning. Alternatively, it can be used after being granulated once using an extruder.

Although it is thought that the aromatic polyester used in the present invention has a molecular weight range suitable for spinning, there are problems such as the lack of a solvent that can uniformly dissolve it depending on the composition and structure, and the lack of precision in the molecular weight measurement method. Therefore, the present inventors introduced "flow temperature" as a physical property value corresponding to the molecular weight suitable for melt spinning conditions.

That is, Flow Tester C manufactured by Takasu Seisakusho! FT-500
Using a nozzle with a diameter of 1 cm and a length of 10 cm, the pressure is 1'0 OK.
The aromatic polyester sample was heated at 4°C/min at p/d.
The sample flows through the nozzle when the temperature is increased at 4
The "flowing temperature" is defined as the temperature that gives an apparent viscosity of 8.000 poise.
The temperature is 80°C, preferably 280-850°C. If the temperature is outside the lower limit of this range, there are problems such as reactions during melting being likely to occur or fiber elongation being difficult to achieve, and if the temperature exceeds the upper limit, the processing (spinning) temperature must be increased. Therefore, there are problems such as decomposition and crosslinking reactions easily occurring, and the load on the equipment increases. The melting section can be exemplified by a plunger, screw, etc. with a heating control function, and the metering section can be exemplified by a gear pump, etc.

In the present invention, the temperature suitable for melt spinning is 280 to 420.
℃, more preferably 800 to 400℃. If the temperature is lower than this range, the load on the device will be large and the melting of the sample will be insufficient, and if the temperature is too high, thread breakage will occur due to decomposition and foaming.

The most important point in the present invention is that the residence time of the melt in the flow path is 80 minutes or less, preferably 2 to It is to be controlled to 2.0 minutes. If the residence time exceeds the upper limit of the present invention, foaming, denaturation, etc. of the melt cannot be avoided, and it may not be possible to provide satisfactory results in terms of spinning operability and the physical properties and uniformity of the final fiber. The materials for such fillers include metals such as gold, silver, copper, iron, aluminum, tin, nickel, titanium, etc. or alloys containing these as main components, alumina, zirconia, titania, silicates, various glasses, sea sand, and ceramics. , ceramic glass such as porcelain can be exemplified, and as for the size of the filler, the average particle size is 0.8 to 5 cm.
Preferably.

Note that the flow path as used in the present invention refers to the path through which the molten material passes from the part where the temperature of the device that transports the polymer quantitatively and raises the temperature to melt it reaches the "flow temperature" of the polymer to the spinneret. Yes, it does not include the path of the transport part of the polymer that has not reached the "flow temperature", and the residence time in the channel is the volume of the channel divided by the volumetric flow rate of the melt per unit time. means.

The fibers spun according to the present invention can be rolled up as they are, or coated with an oil and then rolled up. The winding or drawing speed is 10 to 10,000 sea in, but from the viewpoint of productivity and stable spinning, it is 100 to 2,000 IQ/1 nin.
The thickness and cross-sectional shape of the obtained fibers are selected depending on the use, but from the viewpoint of strength and elastic modulus, the thickness and thread diameter of 1 to 10 deniers are preferable.
However, it can be further increased in strength and elasticity by heat treatment, stretching, or a combination of these treatments.

(Function) By employing the above-described manufacturing method of the present invention, especially the technical means of filling the flow path of the melt with granular material of metal or ceramic sox, the melt at a temperature close to the decomposition temperature can flow into the flow path. It is possible to shorten the residence time of the molten material, effectively preventing foaming, metamorphosis, etc. of the molten material, and to prevent complex paths formed by granular fillers of metal or ceramics with high thermal conductivity. By passing through it, the temperature and agglomeration state of the melt progress to become uniform, and as a result, melt spinning with good operational stability becomes possible, and finally fibers with excellent physical properties and uniformity can be provided. It can be thought that (
Effects of the Invention) As described above, aromatic polyester, which exhibits a behavior significantly different from that of conventional polymers, can be melt-spun with good operational stability, resulting in high strength, high elastic modulus, and uniform physical properties. A noteworthy effect of the present invention is that it has provided a means for industrially advantageous production of excellent fibers, and the fibers obtained by the present invention can be used in tire cords, lobes, cables, FRF
It can be used for lFRTP, speaker cones, safety clothing, tension members, etc.

(Examples) Examples and comparative examples are shown below to explain the present invention in detail, but these are merely illustrative and are not intended to limit the invention.

In addition, the tensile test of the fiber in the example was performed using an Instron universal testing machine 7111180 at a sample interval of 20 wm and a tensile speed of 0.5 m/miH.

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

Reference example p-acetoxybenzoic acid 7.204 (40 mol), terephthalic acid 2.49-(15 mol), isophthalic acid 0.
88 (5 moles) and 4.4'-diacetoxydiphenyl (5.45 to 20.2 moles) were charged into a polymerization tank with comb-shaped stirring blades, and the temperature was raised while stirring under a nitrogen gas atmosphere.
Polymerization was carried out at 830°C for 8 hours. During this time, the acetic acid produced was removed, the polymerization was carried out with strong stirring, the polymer was slightly cooled, and the polymer was taken out of the system at 200°C. The yield of polymer was 97.8% of the theoretical yield with an IQ of 88. This was ground into particles of 2.5 particles or less using a hammer mill manufactured by Hosogumi Micron. When this was treated in a rotary kiln at 280°C for 5 hours under a nitrogen atmosphere, the "flow temperature" was 82.
It became 6℃. Optical anisotropy was observed above 850°C.

Example The polyester of the reference example was melt-spun using a screw extrusion type melt-spinning device consisting of a screw with a diameter of 80 mm, a gear pump for measuring the melt, and a spinning head having a temporary material and a melt reservoir on the back side of the spinneret. I did this. The spinneret has a hole diameter of 0.12 m.

A material with a hole length/hole diameter of 0.8.150 holes was used, and the spinning temperature was 865°C. Note that the width of the flow path is 827 m (melting part 80- of a part of the screw, 45-1 melt storage 202d from the screw to the spinning head melt storage).

Spinning was performed by changing the filling of the granular material in the melt storage and the melt discharge rate of the gear pump to change the residence time of the melt in the channel as shown in Table 1 below, and the spinning operation stability and fiber physical properties were evaluated. . The spinning operation stability is determined by the fineness of the finest single fiber and the uncut spinning duration in 5d spinning, and the fiber properties are determined by the strength and strength fluctuation rate of the after-spun fiber (5d) heat treated in N2 at 820°C for 8 hours. evaluated.

The results are also listed in Table 1.

As is clear from the table above, when the spinning conditions recommended for the present invention are adopted (/L1 to 8), the spinning operation stability, physical properties, and physical property uniformity are significantly improved, while the residence time It is understood that both the operability and the physical properties are unsatisfactory in the case where the requirements are not satisfied (mu 4) and in the case where there is no filler even if the residence time is satisfied (mu 5). In addition, the inner shell value () of Mu4 was 7 because the sample of 5d could not be collected.
This is an evaluation of sample d.

Claims (1)

[Claims] Exhibits optical anisotropy when melted and has a flow temperature of 280-380℃
The aromatic polyester is melted by filling the flow path of a melt spinning device with metal or ceramic granules and controlling the residence time of the aromatic polyester melt in the flow path to 30 minutes or less. A method for spinning aromatic polyester, which is characterized by spinning.