JPH01139811A - Production of polyester fiber - Google Patents

Abstract

PURPOSE:To obtain the title uniform fiber adequately applicable to practical use, by high-speed spinning, under specified conditions, of a polyester prepared by copolymerization of the conventional polyester raw materials with specific naphthalene ring-contg. compound and/or diphenyl compound added in the presence of an organosodium compound. CONSTITUTION:First, a polyester with the chief acid component being terephthalic acid is prepared by incorporating the reaction system with 0.1-50mol%, based on the bifunctional carboxylic acid component, one of the raw materials, of compound(s) of formula I and/or II (R is H or 1-2C alkyl) and an organosodium compound followed by copolymerization. The resulting polyester(melt) is subjected, through a spinneret, to high-speed spinning and the spun yarn is cooled to temperatures higher than the glass transition temperature of the polyester by <=70 deg.C, being passed through a heating zone at >=200 deg.C followed by winding on a take-up.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for producing polyester fiber. More specifically, we aim to improve the melt spinning stability of polyester and 1. The present invention relates to a method for producing polyester fibers having excellent yarn quality, uniformity in thickness, and level dyeing properties, and having fiber physical properties sufficient for practical use, using only a spinning process.

(Prior art) For example, it is known from the Journal of the Japan Institute of Textile Science and Technology, Vol. 33, pages T2O8 to T214, that when polyester is melt-spun, fibers with practically sufficient properties can be obtained through the spinning process alone by increasing the take-up speed. Are known. According to these, in the case of polyethylene terephthalate, for example, when the take-up speed is about 5000 m/min or more, the fiber obtained becomes similar to that of conventional abrasive drawn yarn.

However, if the withdrawal speed is increased, especially 5000 m7
If the time is more than 10 minutes, yarn breakage and single yarn breakage during spinning will significantly increase, resulting in extremely poor operability. In addition, increasing the take-up speed increases the strength and Young's modulus, but at a take-up speed of about 5000 m/min, the mechanical properties are lower compared to fibers obtained by spinning at the conventional take-up speed and drawing in a separate process. It has the following drawbacks. Furthermore, even if the withdrawal speed is increased, 7
The mechanical properties have a maximum value at a speed of about 1,000 m/min, and at speeds higher than that, a decrease in strength, Young's modulus, etc. is observed.

The present inventors believe that the strength and elongation of the spun yarn may be improved by performing some kind of heat treatment during spinning, in order to obtain fibers that can be used in practical use. Although we thought about this and made various studies, the effect was not as high as expected, and the problem of single yarn breakage and yarn breakage during spinning was not satisfactory. .

(Problems to be Solved by the Invention) In the above-mentioned spinning method that combines high-speed spinning and a heating zone in order to obtain fibers that have excellent spinning stability and can be used for practical use only through the spinning process, the spinning conditions Although various studies were conducted on, for example, polymer viscosity, spinning temperature, spinning draft, cooling conditions, etc., it was not possible to improve both spinning stability and fiber properties within the range of spinning conditions employed in operations.

The purpose of the present invention is to solve these problems and improve the spinning stability when melt spinning polyester, as well as to achieve excellent uniformity in yarn quality and thickness, level dyeing properties, and to be sufficiently durable for practical use. An object of the present invention is to provide a method for producing wet polyester fiber using only a spinning process.

(Means for Solving the Problems) The present inventors believed that improving the molten polymer would be effective in eliminating the drawbacks of the conventional method as described above, and from this point of view, they conducted extensive studies. As a result, a polyester obtained by addition-copolymerizing a compound having a specific naphthalene ring and/or a diphenyl compound and adding an organic sodium compound was melt-spun, and after cooling,
The inventors have discovered that spinning at high speed by passing through a heating zone placed below the spinneret improves the spinning stability and also improves the strength and elongation of the resulting fibers, and has thus arrived at the present invention.

That is, in the present invention, after spun polyester yarn containing terephthalic acid as the main acid component is discharged from a spinneret,
[Glass transition temperature of the polyester + 70°C] When the yarn is cooled to a temperature of 70° C. or lower, and then run in an atmosphere at a temperature of 200° C. or higher and taken at a drawing speed of 4000 m/min or more, the polyester is as follows: General formula (I
) and/or the compound represented by the general formula (n) in an amount of 0.1 to 50 mol% based on the difunctional carboxylic acid component that is the raw material of the polyester, and an organic sodium compound is added to the polyester. This is a method for producing polyester fiber, which is characterized in that it is used.

(In the formula, R represents a hydrogen atom or an alkyl group having 1 or 2 carbon atoms.) The polyester in the present invention is mainly polyethylene terephthalate whose main acid component is terephthalic acid. Even in polyesters in which part of the ethylene glycol component (usually 20 mol% or less) is replaced with other difunctional carboxylic acid components, a part of the ethylene glycol component (
It may also be a polyester in which the diol component (usually 20 mol% or less) is replaced with another diol component. Furthermore, the polyester may be copolymerized or mixed with various additives, such as dye-facilitating agents, flame retardants, antistatic agents, hydrophilic agents, colorants, etc., as necessary.

Such polyesters are usually produced by subjecting terephthalic acid and ethylene glycol to an esterification reaction, or by subjecting a lower alkyl ester of terephthalic acid such as dimethyl terephthalate to a transesterification reaction with ethylene glycol, or by reacting terephthalic acid and ethylene oxide. Glycol ester of terephthalic acid and/or
Alternatively, it is produced by producing a low polymer thereof, and then heating the product under reduced pressure to polycondense it until a predetermined degree of polymerization is achieved.

Furthermore, as the polyester to be subjected to melt spinning of the present invention, it is important to add and copolymerize a compound represented by the following general formula (I) and/or general formula (n) and to add an organic sodium compound. .

(In the formula, R represents a hydrogen atom or an alkyl group having 1 or 2 carbon atoms.) The naphthalene compound represented by the general formula (1) has a symmetrical molecular structure and can be easily incorporated into polyester molecules. 2,6-naphthalene dicarboxylic acid, dimethyl 2,6-naphthalene dicarboxylate, and diethyl 2,6-naphthalene dicarboxylate represented by the following formula (III) are preferable because they are easily rare.

(In the formula, R represents a hydrogen atom or an alkyl group having 1 or 2 carbon atoms) As the diphenyl compound represented by the general formula (II),
Preferred are 4,4'-diphenyldicarboxylic acid, dimethyl 4,4'-diphenyldicarboxylate, and diethyl 4,4'-diphenyldicarboxylate represented by the following general formula (IV).

(IV) (In the formula, R represents a hydrogen atom or an alkyl group having 1 or 2 carbon atoms.) Such a naphthalene compound and/or diphenyl compound is used in the number average polymerization of polyester in the polyester manufacturing process. It is added at any stage until the degree of polymerization reaches 30, and then copolymerized by polycondensation reaction to a predetermined degree of polymerization while heating under reduced pressure.

The amount of naphthalene compound and/or diphenyl compound added at this time is 0.1 to 5
It is 0 mol%.

If the added copolymerization amount of the naphthalene compound and/or diphenyl compound is less than 0.1 mol%, yarn breakage during spinning and single fiber breakage will decrease, and mechanical properties such as the strength and Young's modulus of the resulting polyester fiber will decrease. On the other hand, if it exceeds 50 mol %, the softening point of the polyester will drop significantly and no improvement in the mechanical properties of the resulting polyester fiber will be achieved.

The organic sodium compound used in the present invention is preferably a sodium-containing aliphatic carboxylic acid or an aromatic carboxylic acid. Specific examples include sodium salts of acetic acid, propionic acid, myristic acid, balmitic acid, stearic acid, montanic acid, benzoic acid, etc., especially acetic acid, montanic acid,
The sodium salt of benzoic acid is preferred.

The amount of such an organic sodium compound added is 0.0 with respect to the difunctional carboxylic acid component that is the raw material for polyester.
05 to 0.2 mol% is preferable, especially 0°O2N2.1
Mol% is preferred.

If the amount of the organic sodium compound added is less than o, oos mol%, yarn breakage occurs frequently during high-speed spinning, and the effect of improving physical properties is reduced. On the other hand, when the amount added exceeds 0.2 mol%, the spinning filtration pressure (spinning pack pressure) increases,
Yarn breakage and single fiber breakage also occur frequently.

When adding the naphthalene compound and/or diphenyl compound and the organic sodium compound to be added in the present invention, they may be added in powder form or as dispersed or dissolved in a solvent such as glycol.

The polyester thus obtained is subjected to melt spinning,
In the melt spinning in the present invention, a heating atmosphere zone is provided below the spinneret, and after the spun yarn is heat-treated, it is heated to 4000 m.
/ It is necessary to collect at a preparative speed.

That is, the spun yarn obtained by melting and discharging the polyester from a spinneret is cooled to a temperature lower than (Tg + 70°C), preferably to a temperature of (Tg - 40°C) to (Tg + 4Q°C). Here, Tg is the glass transition temperature of the polyester forming the spun yarn.

The spun yarn cooled in this way is immediately heat-treated at an ambient temperature of 200 to 400° C. by running through a heating atmosphere zone. If the yarn temperature immediately before undergoing this heat treatment exceeds (Tg+7Q°C), the homogeneity of the yarn obtained will deteriorate because the heat treatment will be difficult to be uniformly performed. For this purpose, temperatures lower than (Tg +70°C), preferably (Tg
The heat treatment should be carried out at a stage when the temperature is lower than the temperature (g, +40°C).

A heating cylinder or a slit heater is used as the heat treatment means. In particular, a slit heater using infrared rays has better heating efficiency than other heat treatment means, and is most preferable for heat treatment at high spinning speeds. This infrared slit heater is capable of uniformly heating the yarn in a short time in a relatively short heat treatment zone of 50 to 150 al along the running direction of the yarn.

Infrared rays are generated by heating a rod-shaped or coil-shaped heater (electric resistance heating element) to a temperature of about 500°C or higher. For example, a heater is provided in a spiral shape surrounding the running yarn, and the heater is heated to a temperature of about 500°C or higher. It can be easily projected onto the running yarn by heating it to .

In general, the heating atmosphere temperature is such that the spinning take-off speed is relatively low (
4000-5000m/min), lower temperature (
200℃~250℃) is preferable, and relatively high speed (600℃~250℃) is preferable.
0 m/min or higher), use a higher temperature (250°C to 40°C).
0°C) is preferred. These temperatures may be appropriately set depending on the required yarn quality (strength, elongation, Young's modulus, spring shrinkage rate, etc.) of the target polyester fiber. However, in any case, if the heating atmosphere temperature is less than 200°C, the draft rate in the atmosphere is small, the effect of improving the crystallinity of the yarn orientation is small, and it is difficult to achieve the object of the present invention. . On the other hand, temperatures higher than 400° C. are unfavorable because they tend to cause single fiber breakage and breakage in the atmosphere.

After leaving the heat treatment zone, the yarn is coated with a suitable finishing agent (oil agent) using an oiling roller or the like if necessary, and then processed at a speed of 4000 m/min or more, preferably 5000 m/min or more, using a pair of godet rollers or a direct winder. It is picked up at a speed of When the take-up speed is less than 4000 m/min, the properties (strength, elongation, initial modulus, etc.) of the obtained yarn are insufficient for practical use.

(Example) Next, the present invention will be explained in further detail by giving examples.

In the examples, parts are parts by weight, and [η] is the intrinsic viscosity determined from the value measured at 30° C. in an orthochlorophenol solvent.

In addition, the U% value used for uniformity evaluation is the commercially available Ust
The measurement was performed using an EvenSs Te5ter.

Examples 1 to 13, Comparative Examples 1 to 6 970 parts of dimethyl terephthalate, 6 parts of ethylene glycol
40 parts and 0.3 manganese acetate as transesterification catalyst
After stirring, 1 part (25 mmol% to dimethyl terephthalate) was charged into a reactor equipped with a rectification column and a methanol distillation condenser, heated from 140°C to 230°C, and the methanol produced as a result of the reaction was removed from the system. Transesterification was carried out while distilling. 3 hours after the start of the reaction, the internal temperature was 230℃
3.20 parts of methanol was distilled out. Here, 0.22 parts of trimethyl phosphate (30 parts
mmol % of dimethyl terephthalate) and reacted for 10 minutes, 0.0 mmol% of antimony dioxide was added as a polycondensation catalyst.
Add 44 parts (30 mmol% to dimethyl terephthalate) and an organic sodium compound of the type and amount shown in Table 1, and after 5 minutes add 2,6-naphthalene dicarboxylic acid and/or the amount of addition shown in Table 1. diphenyl-4,4'-
Dicarboxylic acid was added to complete the transesterification reaction.

Next, the obtained transesterification product was transferred to a polycondensation reactor equipped with a stirrer and a glycol condenser, and the temperature was gradually raised from 230°C to 285°C, and the polycondensation reaction was carried out under normal pressure, followed by a high vacuum of lmHg. A polycondensation reaction was carried out while lowering the pressure to obtain a [η) 0.64 polymer.

The polyester thus obtained was discharged at 300°C from a spinneret having 24 spinning nozzles with a diameter of 0.3 tm, and cooling air at a temperature of 26°C and a relative humidity of 70% was passed through a 15 m
The spun yarn is cooled by blowing at a linear speed of /min, and after cooling the yarn to 90°C, it is focused on a ring-shaped guide, and then the yarn is heated in an infrared heating slit heater with a length of 100 cs. (The air atmosphere is shown in Table 1), a finishing agent is applied with an oiling roller, and the first
It was collected at the collection speed shown in the table.

The spinnability and physical properties of the resulting yarn are also shown in Table 1.

Incidentally, the yarn physical properties of the conventional drawn yarn have the values shown below.

The spinnability of level dyeing was determined using the conventional drawn yarn as a standard. (In other words, the ○ marks are of the same quality as the above-mentioned drawn yarn, and the When the amount of naphthalene compound and/or diphenyl compound is outside the scope of the present invention (Comparative Examples 1 to
3) If no organic sodium compound is added (
Comparative Example 4) and cases where the take-up speed and heating atmosphere temperature during spinning are outside the range of the present invention (Comparative Examples 5 and 6), there are unsatisfactory points in fiber physical properties, level dyeing properties, or spinnability, and overall Good results were not obtained in the evaluation. On the other hand, when the amount of naphthalene compound and/or diphenyl compound and organic sodium compound added to the polyester is within the range of the present invention (Examples 1 to 10) and the spinning conditions such as take-up speed and heating atmosphere temperature are within the range of the present invention. When it was within the range (Examples 11 to 13), good results were obtained in all of the fiber properties, level dyeing properties, and spinnability, and the overall evaluation was also excellent.

(Effects of the invention) According to the manufacturing method of the present invention, 4000 m 7 minutes or more, especially 5 minutes
000 m It is possible to spin polyester fibers that can be stably spun at high speeds of 7 minutes or more, has excellent fiber uniformity and level dyeing, and has excellent physical properties such as strength and elongation, and can be used for practical purposes. It becomes possible to provide the product only through the process.

Claims (1)

[Claims] 1. After a polyester spun yarn containing terephthalic acid as the main acid component is discharged from a spinneret, it is cooled to a temperature below [glass transition temperature of the polyester + 70°C], and then the yarn is When the strip is run in an atmosphere at a temperature of 200° C. or more and taken at a drawing speed of 4000 m/min or more, a compound represented by the following general formula (I) and/or general formula (II) is used as the polyester. 0.1 to 50 to the difunctional carboxylic acid component that is the raw material for
1. A method for producing polyester fiber, characterized by using a polyester containing an organic sodium compound in an amount of mol %. ▲There are mathematical formulas, chemical formulas, tables, etc.▼・・・・・・( I
) ▲There are mathematical formulas, chemical formulas, tables, etc.▼・・・・・・(II) (In the formula, R represents a hydrogen atom or an alkyl group having 1 or 2 carbon atoms) 2. Represented by the general formula (I) The compound represented by the following general formula (II
The method for producing a polyester fiber according to claim 1, which is a compound represented by I). ▲There are mathematical formulas, chemical formulas, tables, etc.▼・・・・・・(III
) (In the formula, R represents a hydrogen atom or an alkyl group having 1 or 2 carbon atoms.) 3. The compound represented by the general formula (II) has the following general formula (I
The method for producing polyester fiber according to claim 1, which is a compound represented by V). ▲There are mathematical formulas, chemical formulas, tables, etc.▼・・・・・・(IV) (In the formula, R represents a hydrogen atom or an alkyl group having 1 or 2 carbon atoms.) 4. The organic sodium compound is an aliphatic carboxylic acid The method for producing a polyester fiber according to claim 1, which is a sodium salt of. 5. The method for producing polyester fibers according to claim 1, wherein the organic sodium compound is a sodium salt of an aromatic carboxylic acid. 6. The method for producing polyester fibers according to claim 1, wherein the organic sodium compound is a compound represented by the following general formula (V). H_3C(CH_2)_nCOONa...(V
) (wherein n represents an integer of 0 to 28) 7. The method for producing polyester fibers according to claim 1, wherein the organic sodium compound is sodium benzoate. 8. The amount of organic sodium compound added is 0.005 to 0.005 to the bifunctional carboxylic acid component that is the raw material for polyester.
The method for producing polyester fiber according to claim 1, wherein the content is 0.15 mol%.