JPS63273635A - Copolymerized polyester - Google Patents

Abstract

PURPOSE:To obtain a copolymerized polyester giving fiber, film, etc., having improved strength, especially improved Young's modulus, by introducing a specific constituent unit into a recurring unit of a polyester. CONSTITUTION:An imidodicarboxylic acid compound of formula I (X is bivalent aromatic residue, etc.; R is alkyl or H) is added to a reaction system for the production of a polyester before the completion of the reaction to obtain a polyester having a recurring unit of formula II (m is 2-6) and containing >=0.5mol.% unit of formula III (n is 2-6; X is bivalent aromatic residue, etc.).

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a copolymerized polyester from which fibers, films, etc., having excellent strength, especially Young's modulus, can be obtained.

(Prior art) Polyester in general, and polyethylene terephthalate in particular, has excellent mechanical, physical, and chemical properties;
It is widely used for clothing, industrial textiles, magnetic tape, photographic films, and other molded products.

However, in the field of textiles, polyester
Both long fibers and short fibers are required to have high quality, especially improved Young's modulus, due to improvements in productivity in post-processing, spinning processes, etc., and diversification of treatments for imparting functionality.

In recent years, there is a so-called direct spinning method that attempts to obtain polyester fibers that can be used for practical purposes only through the spinning process, but in order to obtain the desired fibers with this method, the winding speed must be increased to at least 5°. However, the strength, especially the Young's modulus, is still lower than that of ordinary drawn yarns, and improvements in this point are needed.

In addition, in the field of film, polyester is widely used as a base film for magnetic tape due to its high strength and high Young's modulus as a biaxially stretched film. Films are desired, and films with high strength and high Young's modulus are also desired.

(Problems to be solved by the invention) The present invention has been made against the background of the above circumstances,
The object is to provide a highly versatile polyester from which fibers, films, etc. can be obtained having improved strength, especially improved Young's modulus.

(Means for solving the problem) In view of the above-mentioned current situation, the present inventors have developed a fiber and/or
As a result of intensive research into the mechanical properties of films, we found that the introduction of a unit expressed by The present invention has been developed based on the discovery that it is effective for

That is, the present invention has the general formula +O(CHz)m OCO
In a polyester mainly composed of repeating units represented by GO+ (m is an integer of 2 to 6), the general formula (n is an integer of 2 to 6, X is a divalent aromatic residue or aliphatic residue) It is a copolymerized polyester characterized by containing at least 0.5 mol % or more of units represented by the above based on the total repeating units of the polyester. - The copolymerized polyester according to the present invention has terephthalic acid as the main acid component, and at least one type of glycol, preferably ethylene glycol, trimethylene glycol,
It may also be a polyester obtained by copolymerizing or mixing, if necessary, a bolier whose main glycol component is at least one alkylene glycol selected from tetramethylene glycol, pentamethylene glycol, and hexamethylene glycol.

Such polyesters are usually produced by subjecting terephthalic acid and glycol to an esterification reaction, or by subjecting a lower alkyl ester of terephthalic acid such as dimethyl terephthalate to a transesterification reaction with a glycol, or by reacting terephthalic acid and ethylene oxide. A first stage reaction to obtain a glycol ester of terephthalic acid and/or a low polymer thereof, followed by a second stage reaction in which a glycol ester of dicarboxylic acid or a low condensate thereof is subjected to a deglycol reaction to obtain a high molecular weight polyester. reaction (ffi condensation reaction).

The copolymerized polyester according to the present invention is
lIOG o% CO3- (m is an integer of 2 to 6) in the repeating unit represented by (n is an integer of 2 to 6, X is a divalent aromatic residue or aliphatic residue) It is necessary that the polyester contains 0.5 mol % or more of the units based on the total repeating units of the polyester. If it is less than 0.5 mol %, it will not be possible to obtain fibers, films, etc. that have excellent strength and Young's modulus when formed into fibers, films, etc.

Moreover, the copolymerized polyester according to the present invention has the general formula: (This page, margins below) O.

(X is a divalent aromatic residue or aliphatic residue, R is an alkyl group or a hydrogen atom) The imidodicarboxylic acid compound represented by It can be obtained by adding it before the completion of the reaction, that is, before the polycondensation reaction starts.

In the compound represented by the general formula, the aromatic residue represented by Residues of linear aromatic polycyclic compounds such as biphenyl, triphenyl, and tetraphenyl can also be mentioned. Other aromatic residues include residues such as diphenyl ether, diphenylthioether, diphenyl sulfone, diphenyl ketone, diphenylmethane, and diphenylethane. Moreover, even if the phenyl group of these diphenyl compounds is replaced with a diphenyl, triphenyl, or tetraphenyl group, it falls within the scope of the present invention.

Furthermore, the aromatic residue may be a residue of a compound in which a hetero atom such as a nitrogen atom is introduced into the aromatic ring. , there are many combinations depending on the bonding position, and all of these compounds fall within the scope of the present invention.0 For example, in the case of a benzene nucleus, 1,4
−11°3−, etc., and in the case of naphthalene nucleus, 1.4−
There are substituents of 21.5-12.6-12.7-, all of which fall within the scope of the present invention.

In addition, examples of the aliphatic residue represented by Mention may be made of the residues of the formula compounds.

Examples of what is represented by R include a hydrogen atom and an alkyl group such as a methyl group and an ethyl group.

The copolyester according to the present invention obtained as described above can be molded into fibers, films, and other molded products by a conventional method and used.

(Examples) Hereinafter, the present invention will be described in detail based on Examples, but the present invention is not limited to these Examples.

Examples 1-11. Comparative Example 1 (Synthesis of imidodicarboxylic acid) Xylene 300mj! Add 60g of trimellitic anhydride to
The diamine compound solution shown in Table 1 (solvent: xylene) was added dropwise to this solution. Water produced by the reaction was azeotropically removed with xylene, and the precipitate was collected and washed with water. , washed with methanol. The resulting solid was dried at 110°C overnight.

When the infrared absorption spectrum of this solid was examined, an absorption peak unique to 5-membered ring imide was found at 1780 cm-'. Further, when the thermal properties were examined using a differential scanning calorimeter, it was confirmed that all the compounds exhibited melting points different from those of the raw materials (Table 1).

(Production of polymer) 970 parts of dimethyl terephthalate, 6 parts of ethylene glycol
40 parts and 0.0 parts of manganese acetate as a transesterification catalyst.
31 parts (25 mmol% to dimethyl terephthalate) was charged into a reactor equipped with a stirrer, a rectification column, and a methanol distillation condenser, and heated from 140°C to 230°C, and the methanol produced as a result of the reaction was distilled out of the system. The transesterification reaction was carried out while allowing the mixture to be released.

Three hours after the start of the reaction, the internal temperature reached 230°C, and 320 parts of methanol was distilled out. Here, 0.22 parts of trimethyl phosphate (30 mmol% to dimethyl terephthalate) was added as a stabilizer, and after reacting for 10 minutes, 0.44 parts of antimony dioxide (30 mmol%) was added as a polycondensation catalyst.
The transesterification reaction was completed by adding the amounts of dimethyl terephthalate) and the synthesized imidodicarboxylic acid compound shown in Table 1.

Next, the obtained reaction 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 at the same time from normal pressure to 1 mm H.
The pressure was lowered to a high vacuum of H and a polycondensation reaction was carried out to obtain a polymer. The thermal properties of the obtained polymer were measured using a differential scanning calorimeter to determine the melting point. Table 1 shows the results of calculating the amount of copolymerization from this melting point using Flory's equation. Further investigation of the infrared absorption spectrum revealed that 1780 on-
' was confirmed to have an absorption peak characteristic of a 5-membered ring imide.

[Drawn yarn]

These polymers were spun at a spinning temperature of 285°C and a discharge rate of 40 g/min from a spinneret having 36 spinning holes with a diameter of 0.3 mm.
The undrawn yarn obtained by spinning at a winding speed of 800 m/min was drawn at a drawing temperature of 83°C, a drawing ratio of 3.5 times, and a drawing speed of 1.000.
The yarn was drawn for 7 minutes to obtain a drawn yarn. Table 1 shows the Young's modulus and strength of this drawn yarn.

[High speed spinning yarn]

Next, the same polymer was spun at a temperature of 290℃ and a diameter of 0.3+u.
The yarn is discharged from a spinneret having 36 spinning holes, and the linear velocity is 1.
It was cooled with cooling air at 3 m/min (26° C., relative humidity 65%) and taken off at a spinning take-off speed of 6.000 m/7 min to obtain a 75 denier yarn. The Young's modulus and strength of the obtained yarn were as shown in Table 1.

〔film〕

Further, using the same polymer, an unstretched original film was prepared at an extrusion temperature of 285° C., and a biaxially stretched film was prepared at a longitudinal stretch ratio of 3.5 times, a transverse stretch ratio of 4.0 times, and a film forming speed of 150 m/min. The Young's modulus and strength of the obtained film were measured. The results are shown in Table 1.

Comparative Example 2 In Example 1, a polymer was produced without adding imidodicarboxylic acid. All other conditions were the same as in Example 1. The results are shown in Table 1.

As is clear from the results in Table 1, when an imidodicarboxylic acid compound is not added or copolymerized (Comparative Example 2)
and addition of imidodicarboxylic acid compound, copolymerization amount is 0
．． It can be seen that when the content is less than 5 mol % (Comparative Example 1), the strength and Young's modulus are low. This tendency is particularly noticeable in the case of high-speed spinning yarns and films. On the other hand, when the imidodicarboxylic acid compound was added and the copolymerization amount was 0.5 mol% or more (Examples 1 to 11), the strength and Young's modulus of the stretched, drawn, high-speed spun yarn, and film were It can be seen that this is improved compared to the comparative example.

(Effects of the Invention) When fibers, films, etc. are molded using the copolymerized polyester according to the present invention, the effect of increasing strength, particularly Young's modulus, can be obtained. In particular, by melt spinning at a high speed of 5,000 m/min or more, fibers with high strength and high Young's modulus comparable to fibers obtained by ordinary spinning and drawing methods can be obtained without the need for a drawing process.

Claims (1)

[Claims] 1. General formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (m is an integer of 2 to 6) In polyester mainly composed of repeating units, general formula ▲ Numerical formulas, chemical formulas, tables, etc. ▼ Contains at least 0.5 mol% or more of the unit represented by (n is an integer of 2 to 6, X is a divalent aromatic residue or aliphatic residue) based on the total repeating units of the polyester. A copolymerized polyester characterized by: