JPH04180920A - Copolyester - Google Patents

Abstract

PURPOSE:To obtain a highly versatile copolyester which can give a fiber, a film or the like having high mechanical properties, especially high Young's modulus by combining structural units of a polyethylene glycol ester of naphthalenedicarboxylic acid and structural units of a polyethylene glycol ester of phthalimide-dicarboxylic acid. CONSTITUTION:A high-Young's modulus polyester which is a copolyester comprising 70-99.5mol% structural units of a naphthalenedicarboxylic acid/alkylene oxide adduct of formula I (wherein (l) is 2-6) and 0.5-30mol% structural units of a phthalimidecarboxylic acid/alkylene oxide adducts of formulas II and/or III (wherein X and Y are each a bivalent aromatic or aliphatic residue) and having an intrinsic viscosity of 0.2-2.

Description

[Detailed description of the invention] a. Industrial application field The present invention provides fibers with excellent mechanical properties, particularly Young's modulus.

This invention relates to a copolyester that can be used to form molded products such as films.

b. Prior Art Generally, polyesters, particularly polyesters obtained by polymerizing aromatic dicarboxylic acids and aliphatic diols such as polyethylene terephthalate, have excellent mechanical, physical and chemical properties, and are therefore used for clothing, It is widely used in industrial fibers, magnetic tapes, photographic films, and other molded products.

However, in the field of textiles, polyester is desired to have higher quality, especially a higher Young's modulus, due to improvements in productivity in post-processing, spinning processes, and diversification of treatments related to imparting functionality.

On the other hand, in the field of films as well, there is an increasing demand for improvements in Young's modulus and the like as films become thinner.

The first method to meet these demands is to develop a process that brings out the potential of polyester as much as possible in the molding process of turning polyester into fibers or films.

For example, in the case of fibers, in the stretching process, the stretching ratio,
By manipulating the heat treatment conditions etc., a higher Young's modulus than before can sometimes be obtained even when the same polymer is used. In addition, even in the case of a film, it is possible to increase the Young's modulus to some extent by performing multi-stage stretching. However, although such process improvements require many equipment improvements, their effects are not sufficient. That is, even with process improvements, the inherent potential of the polymer is not fully brought out, as is clear from the fact that the Young's modulus actually obtained is far lower than the Young's modulus determined by theoretical calculations, for example.

The second method to meet the demand for a high Young's modulus is the development of a polyester that can exhibit a high Young's modulus without significantly departing from the conventional molding process and while maintaining the productivity of the process.

In this method, progress has been made to develop polyesters that are rigid and have excellent linearity, but generally such polyesters have a high melting point and are therefore difficult to process and mold. Furthermore, some types of polyester exhibit optical anisotropy in a molten state, and special steps are often required when forming them into fibers or films.

On the other hand, the development of polyesters with more rigid aromatic rings (e.g. naphthalene skeleton) and flexible aliphatic moieties is progressing, and their Young's modulus has been improved compared to conventional polyesters consisting of benzene skeletons and aliphatic units. of things,
It is difficult to say that they are fully responding to the market's increasing Young's modulus.

C0 Purpose of the Invention The present invention was made against the background of the above circumstances, and its purpose is to develop a highly versatile polyester that can be used to obtain molded products such as fibers and films that have high mechanical properties, particularly a high Young's modulus. It is about providing.

d1 Structure of the Invention As a result of intensive studies to solve the above problems, the present inventors have improved the mechanical properties of polyester, particularly Young's modulus, by introducing an imide skeleton into the repeating unit of polyester. The present invention was achieved by discovering that this is effective.

That is, the present invention provides the following formula (I)
...(I> [wherein p is an integer of 2 to 6] 70 to 95.5 mol% of units represented by the following formula (IF
)...(IF>-EO(CH2+n o-co(]]:TSN-Y-CO
...(III) Copolymerized polyester having a degree of 0.2 to 2.

The present invention will be explained in more detail below.

The copolymerized polyester according to the present invention contains naphthalene dicarboxylic acid as the main acid component, and contains at least one glycol having 2 to 6 carbon atoms, preferably ethylene glycol, trimethylene glycol, tetramethylene glycol, pentamethylene glycol, hexane glycol, etc. An imide structure is introduced into a polyester whose main glycol component is at least one alkylene glycol selected from methylene glycol.

In the above formulas (1) to (I), ρ is an integer from 2 to 6, and ρ=2 is particularly preferable. Ethylene glycol is preferably selected as the glycol.

In the above formula (I), the substitution positions of the carboxyl group on the naphthalene skeleton are 1.5-position, 1.6-position, 1.7-position, 1-position,
There are 8th place, 2.5th place, 2.6th place, 2nd and 7th place, 2nd and 8th place, etc., and any case is included in the scope of the present invention.

Among them, 2.6th place is particularly preferably selected.

Two preferable imide structure-containing units for copolymerization are represented by formula (II) and formula (I[I). All of these are recognized to be effective for the purpose of the present invention, that is, improving the mechanical properties of molded products, particularly Young's modulus. Therefore, only one type of these imide-containing units shown above may be introduced into the polyester, or a plurality of imide units may be introduced into the polyester. However, the content of imide-containing units is 0.5 mol% or more and 30 mol% or less. If the content is less than 0.5 mol%, no significant improvement effect on Young's modulus etc. will be observed when molded into fibers, films, etc.

The content of imide-containing units in the copolymerized polyester naturally has an upper limit from the viewpoint of the polymerizability of the polyester and the melting point and heat resistance of the obtained polyester.
It is preferably at most mol%, more preferably at most 20 mol%. When the content of imide-containing units exceeds 30 mol %, there are problems such as impaired moldability of the obtained polymer and decreased crystallinity.

In the above formulas (II) and (nI), X and Y are divalent aromatic residues or aliphatic residues.

Here, the aromatic residues include benzene residues, residues of aromatic polycyclic compounds such as naphthalene, anthracene, naphthacene, chrysene, and pyrene, and linear aromatic polycyclic compounds such as biphenyl, triphenyl, and tetraphenyl. Mention may also be made of residues of compounds. Other aromatic residues include diphenyl ether, diphenyl-onythyl,
Examples include residues such as diphenylsulfone, diphenylketone, 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. In addition, the compound used as the aromatic residue for X and Y above is at the bonding position! Depending on the combination, there are many combinations, and all such compounds fall within the scope of the present invention.

For example, in the case of benzene nucleus, 1.4-, 1.3-, etc., and in the case of naphthalene nucleus, 1.4-, 1.5-, 2.6-
．． There are 2.7-substitutions, all of which are within the scope of the present invention.

Examples of aliphatic residues include residues of linear alkane compounds such as methylene and ethylene, and alicyclic compounds such as cyclohexane, cyclohexane dimethylene, adamantane, viadamantane, and diadamantane. Residues can be mentioned.

There are no particular restrictions on the polymerization method of the copolymerized polyester according to the present invention, but for example, the following methods (A) and (B) can be used.
This method is exemplified.

(A) Esterification of naphthalene dicarboxylic acid and glycol, or transesterification of lower alkyl ester of acid such as naphthalene caffleboxic acid dimethyl ester with glycol, or transesterification of naphthalene dicarboxylic acid and ethylene oxide. Let's make it react,
A first step reaction to obtain an ester of naphthalene dicarboxylic acid and glycol and/or a low polymer thereof by any method. Subsequently, a second stage reaction (polycondensation reaction) in which a high molecular weight polyester is obtained by a deglycol reaction from an ester of naphthalene dicarboxylic acid and glycol and/or a low polymer thereof. In the polymerization method comprising the first-stage reaction and the second-stage reaction, before the polyester production reaction is completed, the general formula (r
V) Or a copolymerization method according to the general formula (V).

(B) A copolymerization method in which an acid halide of imidodicarboxylic acid coexists in a polymerization method for obtaining a polyester by a polycondensation reaction of an acid halide of naphthalene dicarboxylic acid with a glycol under a basic catalyst.

Among these, the Al method is preferred.

Further, the copolymerized polyester of the present invention has an intrinsic viscosity of 0.2
It is preferable that it is -2.

Note that the copolymerized polyester according to the present invention may be a polyester to which various additives such as an easy-dying agent, a flame retardant, an antistatic agent, a hydrophilic agent, a coloring agent, etc. are added as necessary.

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.

e0 Effects of the Invention When the copolymerized polyester according to the invention is used, the resulting molded product has the effect of improving physical properties, particularly Young's modulus.

Furthermore, it has been found that the copolymerized polyester according to the present invention has an effect of improving moldability compared to the original polyester by introducing an imide structural unit. That is, in the original polyester (0(CH2+1O-CO-O3-co+,!), for example, in fiberization, in order to increase the stretching ratio in the stretching process, it is necessary to provide a special heating device under the spinning cap. On the other hand, the copolymerized polyester of the present invention has improved stretchability without using any special heating device,
The effect of improving the elastic modulus of the drawn yarn was confirmed. Therefore, the copolymerized polyester of the present invention is suitable for obtaining molded articles with high elastic modulus.

f. Example Hereinafter, the present invention will be explained in detail with reference to Examples.

However, the present invention is not limited to these examples.

In the examples, parts indicate parts by weight.

Example 1 (Synthesis of imidodicarboxylic acid) 64 g of trimellitic anhydride (0,
2 mol) was dissolved by heating with stirring. 3.4'~
A solution of 134.4 g (0.1 mol) of diaminodiphenyl ether dissolved in xylene was added dropwise. After a specified amount of water was azeotropically removed with xylene, the precipitate was cooled, collected, and washed with water and methanol.

Obtained imidodicarboxylic acid The yellow powder was dried at 100°C for 10 hours.

The IR spectrum of this yellow powder was measured and showed 171
An absorption peak unique to 5-membered ring imide was confirmed at 50Il-1.

The melting point of this substance was determined to be 365° C. by observation under a microscope with a hot stage.

(manufacture of polymer) 2.100 parts of dimethyl 6-naphthalene dicarboxylate.

178 parts of ethylene glycol and 0.0048 parts of tetrabutyl titanate (<0.03 mol% to 2.6-naphthalene dicarboxylic acid) as a transesterification catalyst and polymerization catalyst)
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 under a stream of air.
The transesterification reaction was carried out while heating to ℃ and removing generated methanol from the system. 9.5 hours after the start of the reaction, the temperature of the inner hot water reached 230°C, and 14.7 parts of methanol was distilled out. Here, the imidodicarboxylic acid compound synthesized earlier was added to 5
They were added in a mol % ratio (to 2,6-naphthalene dicarboxylic acid) and reacted at 230° C. for 10 minutes, and then the transesterification reaction was completed.

Next, the obtained reaction product was transferred to a polymerization reactor equipped with a stirrer and a glycol condenser, and the temperature was gradually raised from 230°C to 280°C. After heating at 280° C. for 30 minutes, the pressure was reduced from normal pressure to 1 m+nHg or less and a polycondensation reaction was carried out to obtain a polymer.

The melting point of the obtained polymer was measured with a differential scanning calorimeter and was found to be 233°C. The IR spectrum of this polymer was measured, and a peak derived from the imide structure was confirmed.

Furthermore, analysis by GPC revealed that the polymer had a molecular weight distribution with a single peak and contained no extremely low molecular weight components, which confirmed that it was a copolymerized polyester having an imide structure. In addition, the intrinsic viscosity ([
η]) was 0.68 dl/g.

(Spinning and Stretching) The obtained polymer was spun using a descending flow tester at a spinning temperature of 290° C. from a cap having a spinning hole of 0.5 ain in diameter to obtain an undrawn yarn. This is stretched at a temperature of 1
A drawn yarn was obtained by drawing at 20°C and a drawing ratio of 7.5 times. The Young's modulus of the drawn yarn is 246 g/de, and the strength is 10.3 g.
/de was.

Example 2 A polymer was obtained using the method shown in Example 1 except that p-aminobenzoic acid was used as the amino compound. The copolymerized imide structural unit has a melting point of 245°C and an IR
From the results of GPC analysis, it was confirmed that it was an imide copolymer.

The intrinsic viscosity of this polymer was 0.69.

The Young's modulus of the drawn yarn with a draw ratio of 7.0 times is 238 g/de
.

The strength was 9.8 g/de.

Example 3 The imidodicarboxylic acid synthesized by the method shown in Example 1 was reacted with diphenyl carbonate to obtain a phenyl ester. This compound was used as a copolymerization component.

A polymer was obtained using the same method as in Example 1 in all other respects. Polymer melting point 233°C, IR.

From the results of GPC analysis, it was confirmed that it was an imide copolymer. The intrinsic viscosity of this polymer was 0.70. The Young's modulus of the drawn yarn with a draw ratio of 7.1 times is 245 g/
de, the strength was 10.0 g/de.

Comparative Example 1 Without adding imidodicarboxylic acid compound (Example 1)
A polymer was obtained using the method shown in . This polymer had a melting point of 267°C and an intrinsic viscosity of 0.69 dl/g. The maximum drawing ratio is 6.0 times, and the Young's modulus of the drawn yarn is 20.
The strength was 9.2 g/de.

Comparative Example 2 A polymer was produced using the method shown in Example 1 except that the amount of imidodicarboxylic acid added was 0.4 mol %. The melting point of the polymer is 266°C, and the intrinsic viscosity is 0.68 dl/
It was g. The maximum draw ratio of this polymer was 6.1 times, and the Young's modulus of the drawn yarn was 207 g/de.

The strength was 9.3 g/de.

Claims (1)

[Claims] The following formula (I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(I) [In the formula, l is an integer from 2 to 6. ] 70 to 95.5 mol% of units represented by the following formula (II)
▲There are mathematical formulas, chemical formulas, tables, etc.▼ ...(II) [In the formula, l is the same as the definition of formula (I). X and Y are divalent aromatic or aliphatic residues. ] and/or the following formula (III) ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(III) [In the formula, l is the same as the definition of formula (I). X and Y are the same as defined in formula (II). ] A copolymerized polyester having an intrinsic viscosity of 0.2 to 2 and comprising 0.5 to 30 mol% of units represented by the formula.