JPH09227767A - Polyester composition - Google Patents

Abstract

(57) Abstract: A polyester composition having excellent hydrolysis resistance and heat resistance is provided. A polyester composition in which (A) an aromatic polyester is blended with (B) an alkaline earth metal salt and (C) a reaction product of a specific phosphorus compound and an epoxy compound in a specific amount.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aromatic polyester for clothing or industrial use which is excellent in hydrolysis resistance and heat resistance. More specifically, the present invention relates to an aromatic polyester which contains an alkaline earth metal salt and a specific phosphorus compound in a fixed ratio and is suppressed from lowering the intrinsic viscosity and increasing the terminal carboxyl group concentration due to molding or moist heat treatment. Particularly, the present invention relates to improvement of hydrolysis resistance of an aromatic polyester containing ethylene terephthalate as a main repeating unit.

[0002]

Aromatic polyesters are widely used as materials for fibers, films and molded articles. Recently, there has been a great demand for its hydrolysis resistance as a raw material for clothing which requires wet heat sterilization and for industrial applications which are used under severe hydrolysis conditions.

For example, there is a demand for improvement in hydrolysis resistance of polyester as a filtration filter or canvas for papermaking in industrial use, and as a surgical gown or uniform in a pharmaceutical factory in clothing use.

Conventionally, in order to improve the hydrolysis resistance of polyester, various techniques for decreasing the concentration of terminal carboxyl groups of polyester have been proposed. For example, Japanese Patent Publication Sho 44
JP-A-27911 and JP-A-54-6051 describe a method of reducing the terminal carboxyl group concentration of polyester by adding a certain epoxy compound. However, in these methods, the reactivity of the epoxy compound is low and the effect is small.

Further, Japanese Patent Publication No. 38-152220 or Japanese Patent Publication No. 46-5389 discloses a method of adding a carbodiimide such as polycarbodiimide or biscarbodiimide to lower the terminal carboxyl group of polyester. Carbodiimide itself is liable to undergo thermal conversion and may cause coloration or deterioration of physical properties of the polyester depending on reaction conditions, and thus its use requires careful attention.

Further, Japanese Patent Laid-Open No. 55-7888 discloses that
A method is described in which a phosphorus compound is added as a light stabilizer to a modified polyester obtained by copolymerizing a polyester with a specific phosphorus compound and adding titanium oxide (TiO ₂ ). Further, in JP-A-55-7889, when a polyester is produced from terephthalic acid and glycol by a direct esterification method, a specific phosphorus compound is added for light stabilization, and titanium oxide (Ti
A method of adding O ₂ ) is described. In order to improve the deterioration of the photostability of polyester due to titanium oxide, which is used as a matting agent,
This is a method of adding a phosphorus compound.

On the other hand, in order to improve the hydrolysis resistance in a wide range of applications of polyesters, from thick denier for industrial use to fine denier for clothing, it is necessary to improve the properties of the polyester itself.

Therefore, the present inventors have found that the hydrolysis resistance of an aromatic polyester obtained by incorporating a specific phosphoric acid ester into the aromatic polyester is improved, and have already filed a patent application (Japanese Patent Laid-Open No. H8 (1998) -8300). -3428).

[0009]

The first object of the present invention is to obtain the aromatic compound obtained by the above-mentioned JP-A-8-3428 during molding or processing of polyester, or during wet heat treatment during use of polyester products. An object of the present invention is to provide an aromatic polyester in which an increase in the number of terminal carboxyl groups of the polyester and a decrease in the degree of polymerization of the polyester are suppressed, that is, an aromatic polyester having excellent hydrolysis resistance and heat resistance.

A second object of the present invention is to provide an aromatic polyester whose strength is not significantly reduced even by molding or wet heat treatment.

Another object of the present invention is to provide aromatic polyesters having improved hydrolysis resistance without the use of specific reagents for reducing terminal carboxyl groups.

Still another object of the present invention is to provide an aromatic polyester having improved hydrolysis resistance which can be obtained by industrially excellent means.

[0013]

Means for Solving the Problems Accordingly, the present inventors have:
As a result of repeated studies for achieving the object of the present invention, hydrolysis resistance of the aromatic polyester obtained by blending an alkaline earth metal salt and a specific phosphorus compound in a specific amount in an aromatic polyester The inventors have found that the heat resistance and heat resistance are further improved, and have reached the present invention.

That is, in the present invention, (A) an aromatic polyester (component A), (B) an alkaline earth metal salt (component B) and (C) a phosphorus compound represented by the following general formula [I] and the following: Reaction product (C component) with an epoxy compound represented by the general formula [II]

[0015]

Embedded image

[In the formula, R ¹ is a hydrogen atom or a carbon atom number 1 to
4 represents an alkyl group having 4 or an aryl group having 6 to 12 carbon atoms. R ² represents a hydrogen atom or —OR ³ , where R ³ represents an atom or group selected from the same definition as R ¹ . ]

[0017]

Embedded image

[Wherein, l ¹ , l ² and l ³ are the same or different and each represents a hydrogen atom or a carbon atom number of 1 to 4].
It indicates an alkyl group, l ⁴ is an alkyl group or an aryl group having 6 to 12 carbon atoms of 1 to 15 carbon atoms. ] It is the aromatic polyester composition which mix | blends, Comprising: The said C component is converted into content of phosphorus (P), and is 3-10.
The content of phosphorus (P) in the B component and the C component is 0 ppm, and the content ratio of phosphorus (P) is represented by the following formula (III) P′-M ′ ≦ 10 (III) [wherein P ′ is a dibase constituting polyester] Indicates the content of phosphoric acid ester (mmol%) with respect to the acid component,
M'represents the content (mmol%) of the alkaline earth metal salt. However, M'is not zero. ] It is an aromatic polyester composition characterized by satisfying these.

The method of the present invention will be described in more detail below.

The aromatic polyester (component A) in the present invention may be any polyester which is usually used as a raw material for fibers, films or molded articles, and particularly polyesters having ethylene terephthalate units as main repeating units, butylene terephthalate units. Is preferably a polyester having a main repeating unit of, or a polyester having an ethylene naphthalate unit as a main repeating unit. The ethylene terephthalate unit, butylene terephthalate unit or ethylene naphthalate unit,
Particularly preferred are polyesters which are at least 80 mol%, in particular at least 90 mol%, in all repeat units. In particular, the aromatic polyester of the present invention is preferably a polyester substantially formed of an aromatic dicarboxylic acid component and a glycol component.

Examples of the dibasic acid component that can be copolymerized with the polyester include isophthalic acid, 2,6-naphthalenedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, adipic acid and sebacic acid. Examples of the glycol component include 1,4-butanediol, neopentylene glycol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol and polyalkylene glycol. As the polyester of the present invention, a polyester obtained by a so-called transesterification reaction obtained by subjecting the dialkyl ester of the dicarboxylic acid and a glycol to a transesterification reaction and then a polycondensation reaction is particularly suitable.

Further, polycarboxylic acids such as trimellitic acid, trimesic acid and pyromellitic acid; and polyols such as glycerin, trimethylolpropane and pentaerythritol can be copolymerized in a small proportion within a range not impairing the object of the present invention.

The aromatic polyester in the present invention contains pigments such as titanium oxide and carbon black, as well as ordinary polyesters, as well as additives such as antioxidants, anti-coloring agents, light resistance agents and antistatic agents. It may have been done.

The intrinsic viscosity [η] of the aromatic polyester in the present invention is preferably 0.45 dl / g or more, and particularly preferably 0.50 dl / g or more. The upper limit of the intrinsic viscosity is preferably 1.3 dl / g, and particularly preferably 1.0 dl / g. The terminal carboxyl group concentration of the aromatic polyester is 1
It is preferably 5 eq / 10 ⁶ g or less, and 10 eq
Particularly preferably, it is / 10 ⁶ g.

The alkaline earth metal salt (ingredient B) in the present invention means a salt of beryllium, magnesium, calcium, strontium, barium and radium among the elements of Group II of the periodic table. Preferred alkaline earth metals are magnesium and calcium.

Specific examples of the alkaline earth metal salt include magnesium acetate and calcium acetate. Moreover, these can mention the thing generally used as a transesterification catalyst. Further, they may be used alone or in combination of two or more.

In the present invention, the component A is compounded with the phosphorus compound (C-1 component) represented by the following general formula [I] and the following general formula [II] in addition to the B component. Reaction product with epoxy compound (C-2 component) (C
Ingredient).

[0028]

Embedded image

[In the formula, R ¹ is a hydrogen atom or a carbon atom number 1 to
4 represents an alkyl group having 4 or an aryl group having 6 to 12 carbon atoms. R ² represents a hydrogen atom or —OR ³ , where R ³ represents an atom or group selected from the same definition as R ¹ . ]

[0030]

[Chemical 6]

[Wherein l ¹ , l ² and l ³ are the same or different and each represents a hydrogen atom or a carbon atom number of 1 to 4].
It indicates an alkyl group, l ⁴ is an alkyl group or an aryl group having 6 to 12 carbon atoms of 1 to 15 carbon atoms. ]

Specific examples of the phosphorus compound of the general formula [I] used in the synthesis of the component C include orthophosphoric acid; monomethyl phosphate, monoethyl phosphate, monopropyl phosphate, monobutyl phosphate, dimethyl phosphate. Phosphoric acid alkyl ester acids such as diethyl phosphate, dipropyl phosphate and dibutyl phosphate; phosphoric acid aryl ester acids such as monophenyl phosphate and diphenyl phosphate; phosphorous acid; monomethyl phosphite, monoethyl phosphite, Phosphorous acid alkyl esters such as monobutyl phosphite and monophenyl phosphite, and aryl phosphite esters such as diphenyl phosphite are preferred, and orthophosphoric acid, monomethyl phosphate, monoethyl phosphate, phosphorus are preferred. Monophenyl acid is good.
That is, when R2 in formula (I) is -OR ^3. These may be a mixture of two or more.

Further, the epoxy compound of the general formula [II] (C-
In the second component), l ¹ , l ² and l ³ are the same or different and each is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, preferably a hydrogen atom. 14
Is an alkyl group having 1 to 15 carbon atoms, preferably 1 to 10 or an aryl group having 6 to 12 carbon atoms, preferably a phenyl group. These may have an ether bond between groups. Specific examples of such epoxy compounds include 1,2-epoxypropane, 1,2-epoxybutane, 1,2-epoxypentane, 1,2-epoxyhexane, 1,2-epoxyoctane, 1,2-epoxy. Nonane, 1,2-epoxydecane, 1,2-epoxycyclohexane, 1,2-epoxyethylbenzene, 2,3-epoxypropyl methyl ether and the like can be mentioned. Among them, 1,2-epoxypropane, 1,2-
Epoxy butane and 1,2-epoxy octane are preferred. Further, these may be a mixture of two or more kinds.

The reaction conditions for obtaining the reaction product of the phosphorus compound (C-1 component) and the epoxy compound (C-2 component) are 70 to 130 ° C., preferably 80 to 130 ° C. for the phosphorus compound (C-1 component). The mixture was heated to a temperature of 120 ° C., the epoxy compound (C-2 component) was added thereto, and the reaction mixture was mixed with 1
It is desirable to continue heating for ~ 7 hours, preferably 2-6 hours. If the reaction temperature is lower than 70 ° C., the reaction does not proceed sufficiently, while if it exceeds 130 ° C., the reaction becomes abrupt and dangerous, and the reaction product is colored, which is not preferable. If the heating reaction time is less than 1 hour, the reaction does not proceed sufficiently, while if it exceeds 7 hours, the reaction product tends to be colored.

The reaction ratio of the C-1 component and the C-2 component is in the range of 1: 1 to 1: 5, preferably 1: 2 to 1: 4, in molar ratio.

The blending ratio of the component C in the present invention is in the range of 3 to 100 ppm, preferably 4 to 50 ppm in terms of phosphorus (P) atom content. If it is less than this range, the effect of thermal stability is not achieved, and if it exceeds this range, the effect of hydrolysis resistance tends to be rather lowered.

Further, the content ratio of the B component and the C component contained in the A component is represented by the following formula (III) P'-M'≤10 (III) [wherein P'constitutes polyester. Showing the content (mmol%) of the phosphoric acid ester with respect to the dibasic acid component
M'represents the content (mmol%) of the alkaline earth metal salt. However, M'is not zero. ], The excellent hydrolysis resistance is superior.

The component C is also used as a stabilizer for the polyester, reacts with M'of the component B to deactivate its transesterification action, or by a direct esterification method without using such a catalyst. It is considered that the addition of a small amount in polyester improves the stability and enhances the potential of the polyester. Therefore, the component C needs to be at least 3 ppm, preferably at least 4 ppm, in terms of phosphorus (P '). On the other hand, if it is not used for deactivating the catalyst (M ') or is added in excess, the component C will act as a hydrolyzable catalyst to some extent, and therefore the (P'- It is suitable that the value of M ') is 10 mmol% or less, preferably 8 mmol% or less.

From the viewpoint of further improving the hydrolysis resistance of the aromatic polyester, the type and the amount of the polymerization catalyst are not a little involved. From the viewpoint of polymerization activity and hue, an antimony compound, particularly antimony trioxide, is usually used as a polymerization catalyst. The amount used is 500 ppm or less, preferably 400 ppm or less in terms of antimony metal (Sb). Especially 150-450pp
m is appropriate. The reason for this is that if an excessive amount of polymerization catalyst is present during melt molding of polyester, the melt-deteriorating property becomes high and eventually the terminal carboxyl group concentration becomes high. Therefore, the amount of the polymerization catalyst is preferably suppressed as much as possible in consideration of the balance between the productivity and the target degree of polymerization.

Since the component C of the present invention contains a polyoxyalkylene glycol group as an organic group, it was feared that this would adversely affect the heat resistance. A polyester prepared by adding phosphoric acid as a stabilizer was polymerized under the same conditions, spun, and compared with the quality of chips and threads. Surprisingly, the polyester of the present invention had a lower intrinsic viscosity and an increased terminal carboxyl group concentration. Was found to be small.

The present invention is not limited to the conventional method of decreasing the terminal carboxyl group concentration in polyester, but is further characterized by the use of the component B and the component C and, if necessary, by specifying the catalyst species and its amount. It is possible to obtain an aromatic polyester excellent in heat resistance and hydrolysis resistance in which a decrease in intrinsic viscosity and an increase in terminal carboxyl group concentration are suppressed under wet heat conditions. Of course, in order to improve the hydrolysis resistance, it is important to lower the terminal carboxyl group concentration, as has been known from the past, and therefore it is important to optimize the polyester polymerization process, to achieve high ultimate viscosity and low terminal by solid phase polymerization. It is possible to add a known carboxyl-lowering agent such as carboxyl group concentration, various epoxy compounds or carbodiimide compounds by any method.

The B component and the C component are blended with the A component. The blending timing is such that the B component and the C component are added to the production process simultaneously or separately at any stage after the production of the polyester is completed. As a preferred method, in the method for producing a transesterification reaction by a polycondensation reaction, the component B is added as a transesterification catalyst in the initial stage of the transesterification reaction, that is, before the lower alkyl alcohol is substantially generated by the transesterification reaction. However, the component C is added as a stabilizer after the final stage of the transesterification reaction, that is, after the generation of 80% or more of the theoretical amount of lower alkyl alcohol generated.

When producing fibers from the modified polyester composition of the present invention, any yarn-making conditions can be adopted without any trouble. For example, 500-2,500m /
Method of melt spinning at a speed of minute, stretching and heat treatment, 1,5
Method in which melt spinning is performed at a speed of 00 to 5,000 m / min, and drawing and false twisting are performed simultaneously or subsequently, 5,000 m
It is possible to employ any spinning conditions such as a method of performing melt spinning at a high speed of not less than 1 minute / minute and omitting stretching depending on the application.

Further, using the modified polyester composition of the present invention, the take-up speed is 2,000 m / min or more, particularly 4,000.
When melt spinning is carried out at a high speed of m / min or more, the amount of insoluble foreign matter is small, and thus the yarn breakage during spinning is significantly reduced. Here, melt spinning conditions of polyester can be arbitrarily adopted as the spinning conditions.

The modified polyester composition of the present invention can also be used for producing films and sheets,
At this time, arbitrary forming conditions can be adopted without any trouble. For example, a method of producing an anisotropic film by applying tension only in one direction after film formation, a method of stretching the film in two directions simultaneously or in any order, a method of stretching the film in two or more stages, and the like. It can be adopted under any conditions.

[0046]

EFFECTS OF THE INVENTION According to the present invention described in detail above, not only does the concentration of the terminal carboxyl groups in the polyester be lowered as in the prior art, but the specific amounts of the B component and the C component are contained in the A component. By blending, a polyester having excellent hydrolysis resistance and thermal stability and having less insoluble foreign matter in the polyester is provided. The reason has not been clarified yet, but it is estimated as follows. That is, when the components B and C are used in combination as a transesterification reaction catalyst and a stabilizer, it is considered that the combination has a high effect of deactivating the transesterification catalyst activity. Phosphoric acid, phosphorous acid, phosphoric acid ester, etc., which have been conventionally used as stabilizers, can be expected to act as an acid if they remain in the polyester as they are and to act as a hydrolysis catalyst under wet heat conditions. On the other hand, it is considered that the stabilizer of the present invention does not accelerate hydrolysis because it rapidly reacts with the transesterification catalyst specified in this patent and the action as an acid catalyst is significantly reduced.

[0047]

The present invention will be described below in detail with reference to examples.

In the examples, all "parts" are parts by weight. The characteristics of the aromatic polyester were measured by the following methods. 1. Intrinsic viscosity [η] Calculated from the value measured at 35 ° C. with an orthochlorophenol solution of 0.6 g / 50 ml. 2. A terminal carboxyl group concentration of 0.10 g / 10 ml of benzyl alcohol was dissolved at 200 ° C., and the content was measured by an automatic carboxyl group measuring device (manufactured by Seiwa Giken Co., Ltd.) by a titration method. 3. Metal analysis After the chips were wet-differentiated, the amount of metal was measured by inductively coupled plasma analysis (ICP) as a dilute hydrochloric acid solution. The ICP is Jarell-Ash Division, Fisher Scientific Co
It was performed using "Atom Comp. Series 800" manufactured by mpany. 4. Strength Stretch speed of 20 cm / mi by autograph in a 25 cm yarn sample at 25 ° C and a humidity of 65%
At n, the strength at break was measured. 5. Strength retention rate A yarn sample was processed at 135 ° C for 60 hours under wet heat decomposition conditions, and its strength was measured to obtain a raw yarn (a yarn before wet heat decomposition treatment).
The strength retention rate was evaluated as the ratio to the strength.

[Examples 1 to 4 and Comparative Examples 1 to 7] 100 parts of dimethyl terephthalate, 64 of ethylene glycol
Part and the mixture of the component B shown in Table 1 gradually at 230 ° C.
The mixture was heated to 40 ° C., the methanol was distilled off to cause the transesterification reaction, and then the C component shown in Table 1 was added. After 5 minutes, antimony trioxide and then 0.4 parts of titanium dioxide were added to an ethylene glycol slurry and added. A polymer was obtained. The obtained low polymer was heated to 265 ° C. and the polymerization reaction was started by reducing the pressure. Polymerization reaction takes 30mmH over 30 minutes
g, the intrinsic viscosity [η] within 1 mmHg in the next 30 minutes
Was increased to about 0.60 dl / g to complete the polymerization reaction. The obtained polymer was dried at 160 ° C. for 4 hours, spun at a spinning temperature of 290 ° C. and a winding speed of 400 m / min, and then preheated at 80 ° C. and heat set at 160 ° C. and stretched 5 times to obtain a 24/40 de multi-polymer. A filament was obtained. Table 2 shows changes in the intrinsic viscosity [η] in the spinning process, an increase in the terminal carboxyl group concentration, and hydrolysis resistance (strength retention).

In Table 2, the chip [η]_cAnd [C
OOH]_cAre the polyesters obtained by polymerization, respectively.
Terchip's intrinsic viscosity (dl / g) and terminal carboxy
Sil group concentration (eq / 10⁶g) of the spun sample
[Η]_fAnd [COOH] _fAre spun by
Viscosity of multifilament obtained (dl / g)
And terminal carboxyl group concentration (eq / 10⁶show g)
You. Also, in the quality change [η]_fcThe spinning pole
Amount of decrease in limiting viscosity ([η]_f-[Η]_c), And also
[COOH]_fcIs the terminal carboxyl group concentration by spinning
Increase ([COOH]_f-[COOH]_c).

[0051]

[Table 1]

[0052]

[Table 2]

As is clear from these results, the polyesters of the present invention (Examples 1 to 4) were excellent in heat resistance and hydrolysis resistance because the intrinsic viscosity during spinning was low and the concentration of terminal carboxyl groups was small. You can see that it is expensive. Withstanding it, the phosphorus compounds other than the present invention (Comparative Examples 1, 2 and 7) cannot obtain sufficient heat resistance and hydrolysis resistance.

On the other hand, when a compound other than an alkaline earth metal salt is used as the transesterification catalyst, the effect of improving the hydrolysis resistance to some extent can be seen by adding a predetermined amount of the phosphorus stabilizer of the present invention. It is far from a satisfactory level (Comparative Examples 3 and 4).

Even if the phosphorus stabilizer of the present invention was used, if the addition amount of the phosphorus stabilizer was more than a certain ratio as compared with the transesterification catalyst (M '), the catalyst was not deactivated. It is recognized that the phosphorus stabilizer tends to accelerate hydrolysis (Comparative Examples 5 and 6).

Claims (4)

[Claims] 1. (A) Aromatic polyester (component A)
And (B) alkaline earth metal salt (B component) and (C)
A reaction product of a phosphorus compound represented by the following general formula [I] and an epoxy compound represented by the following general formula [II] (C
Ingredient) [Chemical formula 1] [In the formula, R ¹ represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 12 carbon atoms. R ²
Represents a hydrogen atom or —OR ³ , and R ³ represents an atom or group selected from the same definition as R ¹ . ] [Chemical 2] [Wherein, l ¹ , l ² and l ³ are the same or different and each represents a hydrogen atom or an alkyl group having 1 to ⁴ carbon atoms, and l ⁴ is an alkyl group having 1 to 15 carbon atoms or the number of carbon atoms 6 to 12 aryl groups are shown. ] It is the aromatic polyester composition which mix | blends, Comprising: This C component contains 3-100 ppm in conversion of content of phosphorus (P),
The content ratio of phosphorus (P) in the B component and the C component is represented by the following formula (III) P'-M'≤10 (III) [wherein P'is phosphorus based on the dibasic acid component constituting the polyester] Indicates the content of acid ester (mmol%),
M'represents the content (mmol%) of the alkaline earth metal salt. However, M'is not zero. ] The aromatic polyester composition characterized by satisfying these. 2. The polyester composition according to claim 1, wherein the aromatic polyester (component A) has an intrinsic viscosity of 0.45 dl / g or more and a terminal carboxyl group concentration of 15 EG / 10 ⁶ g or less. 3. The reaction product (component C) is produced by reacting the phosphorus compound and the epoxy compound at a molar ratio of 1: 1 to 1: 5 and at a temperature of 70 to 130 ° C. The polyester composition according to claim 1, which is a product. 4. The phosphorus compound represented by the general formula [I]
And R^TwoBut-OR ^ThreeA compound represented by
1. The polyester composition according to 1.