JPS61282423A - Production of polyester yarn - Google Patents

Abstract

PURPOSE:To obtain thin and long fibers, by molding a mixture of an aromatic polyester having specific melt viscosity and a polymer inert and non-compatible under a melt blending condition into a film, etc., and splitting it by a mechanical means. CONSTITUTION:95-65wt% film-forming aromatic polyester A is in a molten state blended with 5-35wt% polymer B inert and non-compatible under a melt blending condition, in a condition satisfying the formulas [etaA and etaB are melt viscosity (poise) of the aromatic polyester A and the polymer B at a temperature to spin the mixture at<=10<3>sec<-1> shear rate, respectively; x is wt% of the aromatic polyester A in the mixture]. The blend is molded into filament, tape or film and slit and fibrillated by a mechanical means.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Application The present invention relates to a new method for producing polyester fibers. More specifically, the present invention relates to a method for producing polyester fibers in which a mixture of mutually incompatible polyester and other types of polymers having a specific melt viscosity is molded, and then fissures are introduced by mechanical means into fibrillar fibers.

PRIOR ART It has been known in the art to mix fiber-forming polyesters and other incompatible thermoplastic polymers and spin them into fibers. These conventional methods include, for example, extracting the polymer with a solvent after spinning, or introducing a hollow part into the fiber by mechanical means such as beating or friction, making it into a non-woven fabric, or making it into a powdered fiber. It is something to do. For example, polyester and other polymers are mixed in a ratio of 90:10 to 60.
:40 ratio, forming it into a fiber or film, stretching it, and beating it to make it into fibers, only a non-woven fabric (mesh-like) could be obtained, or the fiber length could not be reached. Only a short powder-like product was obtained.

<Object of the invention> The present invention provides a filament made of a mixture of an aromatic polyester (4) and another thermoplastic polymer (Bl).

The aim is to provide a method for easily obtaining extremely thin (and long) fibers by forming the fibers into tapes, films, etc., and then using mechanical means to introduce °C cracks.

The conventional method of composite spinning and then splitting to obtain thin fibers has drawbacks such as requiring two or more extruders and not being able to obtain sufficiently thin fibers. In addition, conventional methods of mixing and spinning two types of polymers using a melt-mixing method such as a static mixer have drawbacks such as only being able to obtain a non-woven fabric or making it difficult to form fibers unless a large amount of the other type of polymer is used.

The object of the present invention is to provide a method for producing thin and long polyester fibers using a single extruder, without such disadvantages.

4; Structure of the Invention> The present inventors have discovered a method for easily producing thin and long polyester fibers. On the other hand, when a polymer is used in combination with a polymer that is substantially inert and incompatible under melt-mixing conditions, even if the molten mixture is formed into filaments, it is easy to split the filaments by mechanical means. It was discovered that fibers that are thin and long at temperature can be obtained, and as a result of further intensive studies, the present invention was developed.

That is, the present invention provides fiber-forming aromatic polyester (A
) 95 to 65 weight percent and substantially incompatible, inert and stable polymer Q3)5 to the polyester
~35% by weight of the filament.

After forming into a tape or film, cracks are introduced into the formed product by mechanical means to form a polyester fiber bundle, and the viscosity ηA of the aromatic polyester and the viscosity of the polymer (B) are as follows This is a method for producing polyester fiber characterized by satisfying the following formula.

Formula log ηz>a (95-at)” +b
a=(14,07-4,2X log 1.)XI
O-4b = 5.64-0.87 x 1ogW.

65≦x≦95 The aromatic polyester (2) used in the present invention includes terephthalic acid, 2,6-naphthalene dicarboxylic acid, 2,
7-Naphthalene dicarboxylic acid.

4.4'-Diphenoxyethanedicarboxylic acid.

The main acid component is aromatic dicarboxylic acids such as 414'-diphenyldicarboxylic acid, and aliphatic acids such as ethylene glycol, trimethylene glycol, tetramethylene glycol, hexamethylene glycol, cyclohexane dimetatool, bisphenol A, and bisphenol sulfone. ,
It is a polyester whose main glycol component is an alicyclic or aromatic diol compound, and furthermore, a polyester whose main component is an aromatic oxycarboxylic acid such as 4-hydroxymethylbenzoic acid or 4-(β-hydroxyethoxy)benzoic acid, and a co-polyester thereof. It may also be a polymer. Among these, polyalkylene 7-talates such as polyethylene terephthalate, polypropylene terephthalate, and polybutylene terephthalate are particularly preferred since polyester fibers with high strength, high elastic modulus, and thin single yarns can be obtained.

These aromatic polyesters may be copolymerized with a third component I or 1 as long as the properties required for the resulting polyester fibers are not impaired. Examples of the third component include dicarboxylic acids such as isophthalic acid, phthalic acid, cyclohexanedicarboxylic acid, adipic acid, and sebacic acid, and ester-forming derivatives thereof, and diol compounds such as neopentyl glycol, polyethylene glycol, and polytetramethylene glycol. and oxycarboxylic acids such as caprolactone.

Furthermore, trimellitic acid, pyromellitic acid, glycerin, trimethylol polyester is used within the range where the resulting polyester is substantially linear.

A polyfunctional compound such as pentaerythritol may also be copolymerized.

Polymer (B) used in combination with the aromatic polyester (5)
l must be an inert, stable polymer that is substantially incompatible with the aromatic polyester (5) in a molten state, and must also satisfy the following specific viscosity conditions. An example of such a polymer is polyethylene.

Polymer 1 Polymerized vinyl monomers such as pyrene, polystyrene, and poly-α-methylpentene, as well as their 10-unit copolymers, random copolymers, and poly(meth)acrylic acids such as polymethyl methacrylate Ester, nylon-6, nylon-6/6. Examples include polyamides such as nylon 11 and those obtained by graft copolymerizing a third component with these polymers such as ABS resin.

Among these, those obtained by (co)polymerizing vinyl monomers are particularly preferred because they can easily introduce cracks even if the amount added is small, and thin and long polyester fibers can be obtained.

It is important that the following relational expression be satisfied between the melt viscosities ηA and ηB of the aromatic polyester and polymer 031.

log ηB>a (95-x)” +ba=(1
4,07-4,2X1ogηB)XIO-4b =5.
64-0.87

b=5.94-0.87Xlog η.

If the melt viscosity of the aromatic polyester powder satisfies the above conditions, η4 will be thick (certainly, the obtained polyester fiber will be long), which is preferable, but if this is not satisfied and η4 is small, then η4 will be thick. This is not suitable because the polyester fibers become short or powdery.

The content of aromatic polyester (5) in the mixture is
Must be 95-65 weight percent, 90-7
0 weight percent is preferred. If it is outside this range, even if the melt viscosity of the aromatic polyester (polyester and polymer) satisfies the above relational expression, the resulting polyester fibers may become short or other polymers may be present in the polyester fibers. A large amount remains, which is not appropriate. On the other hand, if the amount is too large, cracks cannot be easily introduced by treating the molded body with various methods, and the desired polyester fibrous material cannot be obtained.

Any method can be used to mix the aromatic polyester (4) and the polymer (B), but it is important to mix them intimately. For example, (1) a monomer of aromatic polyester (A) or a precursor such as an oligomer thereof is used as polymer 03.
There are methods such as a method of polymerizing the aromatic polyester (2) by subjecting the mixture to the aromatic polyester (2) under reduced pressure to polymerize the aromatic polyester (2) under reduced pressure, and (2) a method of melt-mixing the aromatic polyester (3) and the polymer.

Each of the methods (1) and (2) has its own advantages and can be selected as appropriate. In other words, method (2) has the advantage that existing aromatic polyesters can be used as they are and does not require new polymerization, but when aromatic polyesters (5) with high viscosity are required, , it is necessary to separately polymerize for a long time using solid phase polymerization or the like. On the other hand, in the method (li), fluidity is easily maintained even if the melt viscosity of the aromatic polyester (3) is increased by increasing the polymerization degree, and the desired melt viscosity (polymerization degree )
It is preferable because it has the advantage that it is easy to obtain polyester.

(The mixture obtained by method Ii can be obtained by directly molding the molten mixture obtained by polymerization [7]. .

In addition, when the mixing method (2) is adopted, the mixing method is, for example, a pelletized and/or powdered aromatic polyester (2).
This can be sufficiently carried out by the usual method of mixing and polymer 031, feeding the mixture to an extruder, and melting and mixing at a temperature equal to or higher than the melting point of the high melting point type compound. Even in this case, a molding nozzle may be attached to the tip of the extruder and the product may be directly molded (or, after being made into pellets, it may be molded again using a normal method).

Next, the melt mixture can be molded using the usual melt molding method applied to ordinary polyester. For example, in the case of forming into a filament, a method can be used in which the molten polymer is discharged from a spinneret having spinning holes and then wound up after cooling. At this time, the winding speed is 2000
A method of stretching after winding at a relatively low spinning speed of m/min or less,
A method of winding at an intermediate speed called POY, and 4000
Any conventionally known method, such as a method in which winding and stretching are not carried out at a high speed of m/min or higher, can be appropriately selected and employed. The obtained undrawn yarn can be drawn and heat-treated by a conventional method, if necessary.

The thickness and thickness of the filament, tape, or film obtained in this way may be any thickness as long as a large number of cracks can be introduced into the molded product by the mechanical means described below (there are no particular limitations, and the thickness may vary depending on the selected mechanical means). However, if the filament is too thick or too thin, it will be difficult to introduce many cracks, so the filament diameter should be 10 μm or more.
10m+ is preferable. Also, for tapes and films, the film thickness is preferably 10 μm to 2 mI for the same reason.

In addition, prior to molding, the temperature of the aromatic polyester (to) and/or
Alternatively, additives commonly used in polymer [F]) may be blended in advance.

Examples of such additives include talc, clay, kaolin, titanium oxide, mica, and silica.

Examples include pigments such as graphite, colorants, ultraviolet absorbers, oxidation stabilizers, fluorescent brighteners, flame retardants, plasticizers, and the like.

The molded product obtained by C.C. is made into ultrafine fibers by mechanical means using impact force, frictional force, etc. such as beating and abrasion, and a large number of cracks are introduced into the molded product.Such a method For example, the method used by Valp Industries may be used as is, or there may be a method in which the filament is crushed by passing it between narrow rollers and then subjected to vibration or whipping action using a turbulent air jet. An appropriate method may be selected from among these methods depending on the type of aromatic Boriesderm) and polymer) and the use of the resulting ultrafine fibers.

The average diameter of the cross-sectional circumscribed circle of the single fibers of the polyester fiber bundle thus obtained is 5 μm or less, and the fiber length of the single fibers is 5 m or more, but the melt viscosity of the mixture It is preferable to increase the melt viscosity of the aromatic polyester (3) to such an extent that the temperature does not become too high and it becomes impossible to spin the polyester fiber bundle. It is preferable to increase the melt viscosity of the polymer (B) within a range that satisfies the above formula, since the average cross-sectional multi-liquid circle diameter of each single yarn of the obtained polyester fiber bundle becomes small.

<Effects of the Invention> As explained above, in the present invention, molding (7, later,
By introducing a large number of cracks into the molded product using mechanical means [7] and making it into a fibril-like shape, the single fiber diameter can be extremely small (
Moreover, long polyester fiber bundles can be easily obtained. The polyester fiber bundles obtained can be used in a wide range of fields such as clothing, nonwoven fabrics, paper manufacturing, and filters.

<Examples> The present invention will be explained in more detail with reference to Examples below, but the present invention is not limited thereto. In addition, in the examples, percentages are percentages by weight unless otherwise specified.

Example 1 An example in which polyethylene terephthalate was used as the aromatic polyester (2) and °C high-pressure polyethylene was used as the polymer IB).

Polyethylene terephthalate (PET') with an intrinsic viscosity of 1.06 (melt viscosity at 285°C: 8700 voids) and high-pressure polyethylene (PK) (manufactured by Ube Industries J519:
(melt viscosity at 285°C: 640 voids) were blended in the form of chips at the proportions listed in Table 1.

The blended chips were dried under reduced pressure at 100°C for 8 hours, then supplied to a screw extruder, melted and kneaded at 285°C, extruded through a nozzle with a hole diameter of 1 m, and wound at a speed of 400 m for 7 minutes to form a monofilament with a thickness of 500 β. I got it. This monofilament was stretched 3.7 times in hot water at 80°C, and then passed between two rollers with a gap of 0.1 m between them and pressed 1. Vibration and whipping effects were applied by crushing and then applying a high-pressure air jet. The results are shown in Table IK.

In the scope of the present invention, et d, ultrafine fiber bundles with a small average fiber diameter and long fiber length can be obtained, whereas in a, which is outside the scope of the present invention, the division is not sufficiently performed and ultrafine fiber bundles are obtained. In cases 1 and 3, the fibers were cut when the air jet was applied and did not become ultrafine fiber bundles.

Example 2 An example in which aromatic polyester (2) was polymerized in polyethylene using polymers ) and [, and molded as it was.

162 parts of dimethyl terephthalate, 106 parts of ethylene glycol, and tetrabutyl titanate were added to dimethyl terephthalate at -C40 mmol%.
Raise the temperature gradually to 240℃ over 3 hours (1)
, methanol by-produced was distilled off and transesterification was carried out. The obtained bis(β-hydroxyethyl) terephthalate was transferred to a polymerization can, and 40 parts of polyethylene (Sumikasen G307, manufactured by Sumitomo Chemical Co., Ltd., melt viscosity at 285°C, 124 voids) was charged, and the temperature was gradually raised from 200°C. The degree of vacuum was also increased, and finally the polycondensation reaction was carried out at 275° C. and a pressure of 13 Pa for the time shown in Table 2. The resulting mixture of polyethylene terephthalate and polyethylene was discharged from the polymerization can into a chip.

The chips were dried under reduced pressure at 100°C for 8 hours, fed to a screw extruder, melted at 285°C, extruded through a spinneret with a pore diameter of 1, rolled up for 200 ml, and heated using a heated roller at 100°C. The yarn was drawn 4 times to obtain a drawn yarn having a thickness of 100 μm. This drawn yarn was cut into short fibers by 5 van K, and then beaten and split using a high-density refiner manufactured by Kumagai Riki Kogyo ■ to produce bulb-shaped ultrafine fibers.

The cross section of this fiber was examined using a z-ray microscope at a magnification of 3000 times, and the average single fiber diameter was as shown in Table 2.

In case a outside the present invention, when beaten, only short fibers were obtained and most of the fibers were in the form of powder, but in cases 3 and c according to the present invention, ultrafine pulp-like fibers with an extremely fine single fiber diameter were obtained.

Example 3 An example in which polystyrene was used as the polymer and polyethylene terephthalate was used as the aromatic polyester.

Polyethylene terephthalate with intrinsic viscosity 0.86 (melt viscosity 3400 poise at 285° C.) and polystyrene (ps) (Idemitsu Petrochemical Exhibition, Idemitsu Styrene HF-10, NF-20).

H'H-30, melt viscosity at 285 DEG C. (245 poise, 410 poise, 560 poise, respectively) was 20% and was dried in the form of chips. The chips were thoroughly dried, fed to a twin-screw extruder, melted and kneaded at 285°C, and then extruded through a die to form a film having a width of 5 oz and a thickness of 0.5 tea. This unstretched film was stretched 3.5 times in the machine direction at a temperature of 110° C., and then split into fibers in the same manner as in Example 1. The results were as shown in Table-3.

Table-3

Claims (1)

[Scope of Claims] A fiber-forming aromatic polyester (A) of 95 to 65 percent by weight and a polymer (B) that is substantially incompatible with the polyester, inert and stable, and 5 to 35 percent by weight. It consists of forming a molten mixture into a filament, tape or film, and then introducing cracks into the formed product by mechanical means to form a polyester fiber bundle,
Viscosity η_A of aromatic polyester (A) and polymer (B
A method for producing polyester fiber, characterized in that the viscosity η_B of ) satisfies the following formula. Formula logη_A>a(95-x)^2+ba=(14
．． 07-4.2×logη_B)×10^-^4b=5
．． 64-0.87×log η_B 65≦x≦95 [However, η_A and η_B are the aromatic polyester (A) and polymer (B ) melt viscosity (
poise) and x is the weight percent of aromatic polyester (A) in the mixture. (2) The method for producing polyester fibers according to claim 1, wherein the aromatic polyester (A) is polyalkylene terephthalate. (3) The method for producing polyester fibers according to claim 1 or 2, wherein the polymer (B) is an olefin or styrene polymer. (4) The amount of aromatic polyester (A) in the mixture is 70
90% by weight of the polyester fiber according to any one of claims 1 to 3. (5) The method for producing polyester fibers according to any one of claims 1 to 4, wherein the length of a single fiber of the obtained fiber is 10 mm or more.