JPS5819326A - Production of haze-free polyester - Google Patents

Abstract

PURPOSE:To obtain a high-softening point, transparent polyester, by polycondensing a dicarboxylic acid with a glycol in the presence of a glycol-soluble Mn, Mg or Ca compound and an alkali metal compound, the last two being used at a specified mol ratio. CONSTITUTION:The purpose polyester is obtained by mixing and reacting (A) a terephthalic acid-based dicarboxylic acid component or its esterifiable derivative, (B) an ethylene glycol-based glycol component, (C) about 0.015-1mol%, based on formed polyester, glycol-soluble metallic compound selected from Mn, Mg and Ca compounds (e.g., manganese chloride, manganese acetate), (D) a glycol-soluble alkali metal compound (e.g., lithium chloride, sodium ethylate) in an amount satisfying the formula, wherein M is the total number of mols of component C and A is that of component C and (E) a necessary polymerization catalyst.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a highly polymerized polyester that is transparent, free of haze, and has a high softening point, which is useful for obtaining films and bottles for stretch molding. Saturated linear polyesters, represented by polyethylene terephthalate, have excellent mechanical properties, heat resistance, weather resistance, electrical insulation resistance, and chemical resistance, and are therefore widely used in the form of films and other molded products. When these polyesters are applied to a biaxially stretched photographic film, it is essential that the film be transparent and free from fogging in order to obtain clear images of objects. Also.

When applied to biaxially stretched films for magnetic tapes, capacitors, etc., the required properties are becoming more sophisticated.In particular, in magnetic tape applications, surface smoothness is required which does not accompany the increase in recording density. There is a growing demand that the materials do not contain particles, etc.

Further, polyethylene terephthalate is finally cold-injected into a cylindrical molded product, heated to a temperature above the glass transition temperature in a range of 140°C, and stretched and blow-molded to form a bottle. When applying this to containers for soft drinks, etc., it is necessary to provide transparency comparable to existing glass bottles in order to allow the product to be rubbed without reducing its commercial value.

However, in the method for producing polyethylene terephthalate, usually an esterification reaction is carried out between terephthalic acid and glycol, or a transesterification reaction is carried out between an ester derivative of terephthalic acid and glycol to obtain bis(hydroxyethyl) ester of terephthalic acid. The process consists of one step and a second step of polycondensing the obtained compound under high temperature and reduced pressure.1 Normally, appropriate catalysts are used in each of the above two steps, and these are the cause of lumps in the final product. It is known that As a countermeasure against these problems, it has been known to add a phosphorus compound when obtaining polyesters or polyethylene terephthalate. For example, phosphoric acid is disclosed in Japanese Patent Publication No. 54-5144 and Japanese Patent Publication No. 52-6897.

The addition of phosphoric acid alkyl ester and trivalent phosphorus compound
Japanese Patent Publication No. 55-24457 proposes the addition of partially alkylated phosphoric acid. Addition of the various phosphorus compounds described above involves reacting the remaining catalyst in the system with the phosphorus compounds.1
From this, the insoluble particles caused by the residual catalyst e are transferred to the polymer t.
On the other hand, it is interpreted that it has the function of solubilizing and making the final polyester transparent. However, these phosphorus compounds also affect polymerization catalytic ability.

It is also well known that when a large amount of monopolymerization catalyst is added for the purpose of improving transparency, the catalyst becomes inactive. On the other hand, when a large amount of phosphorus compound is added.

Undesirable side reactions such as the production of diethylene glycol (hereinafter referred to as DEG) occur, which lowers the softening point of the obtained polymer, causing problems such as film tearing during the film forming process and adhesion to rolls. Further, even if transparency is imparted by increasing the amount of the phosphorus compound, the transparency will be insufficient.

On the other hand, it has been known to add an alkali metal compound for the purpose of suppressing the by-product of DgG and a decrease in the softening point (for example, JP-A-49-45014, JP-A-55-84522). Public notices, etc.). However, the addition of alkali metal compounds is described in Japanese Patent Application Laid-Open No. 48-79271, for example.
No. 57890, Japanese Patent Application Laid-Open No. 1983-57890,
It is also known that fine particles are generated and transparency is impaired, as disclosed in JP-A-98597 and JP-A-50-143894.

The present inventors have discovered the disadvantages of such conventional methods, particularly in the case of yarns with added phosphorus content, which have a large decrease in the softening point.

In addition, as a result of intensive study to improve the lack of transparency and the fact that adding alkali metals to improve the softening point would impair transparency, we found that manganese, magnesium and calcium The present inventors have discovered that transparency can be significantly improved by polycondensing one or more compounds selected from the following in the presence of an alkali metal compound, and have completed the present invention.

An object of the present invention is to provide a method for producing polyester that is transparent without haze and has a high softening point. In order to achieve such an object, the present invention involves the production of a dicarboxylic acid whose main component is yoterephthalic acid or its ester-forming derivative, a glycol whose main component is ethylene 11-col, and a carbo-1J ester. 1 selected from manganese, magnenium, and calcium that satisfies the formula
When the polycondensation reaction is completed in the presence of at least one glycol-soluble metal compound 3 and a glycol-soluble alkali metal compound (having an X configuration).

0.01≦A/M≦0.5 The glyco-21-based manganese, magnesium, and calcium used in the method of the present invention are chlorides, bromides, etc., rogenides, and acetates.

Examples include aliphatic carboxylates such as propionates, alcoholates such as hydroxides, methylates, ethylates, and ethylene monocholates, specifically manganese chloride and magnesium chloride.

Examples include calcium chloride, manganese acetate, magnesium acetate, calcium acetate, manganese hydroxide, magnesium methylate, calcium glycolate, and the like.

In addition, the glycol-soluble alkali metal compounds used in the method of the present invention include hydrides, hydroxides, halides such as chlorides and bromides, aliphatic carbhonates such as acetates, propionates, and oxalates. , methylate, ethylate, alcoholade such as ethylene dalicolate, and alkylated products such as ethyl and butyl.

One specific example is lithium hydride and sodium hydride.

Examples include potassium hydroxide, lithium chloride, sodium bromide, lithium acetate, sodium acetate, potassium propionate, lithium methylate, sodium ethylate, potassium glycolate, butyl lithium, etc., and one or more of these can be used in combination. You can.

The amount of one or more glycol-soluble metal compounds selected from manganese, magnesium, and calcium used in the method of the present invention is 0.01% based on the polyester produced.
It is preferable that it is 5-1.0 molar ratio. Usage amount is 1.
When the amount is more than 0 molar ratio, the coloring and heat resistance of the resulting polyester tend to decrease, and particles are generated in the polymer, resulting in insufficient improvement in transparency. Also, the amount used is 0
．． If it is less than 0.015 molar ratio, for example, the transesterification reaction will be slow, and furthermore, when forming the produced polymer into a film, 4? When forming a thin film, the electrostatic casting method cannot be applied, which is undesirable because thickness unevenness and film tearing occur.

In the method of the present invention, the glycol-soluble alkali metal compound is glycol-soluble manganese.

The following formula % formula % is used for one or more metal compounds selected from magnesium and calcium, where M is used in the amount of manganese, magnesium, and calci, and more preferably 0.015<A/M<0.4. and i is also preferably 0.02<A/M<0.2. If the molar ratio (A/M) of the gold scrap compound is less than 0.01, there are problems such as the effect of improving transparency being small and the softening point of the polymer becoming low. Furthermore, if the molar ratio (A/M) of the metal compound is greater than 0.5, the effect of improving transparency will not be sufficient, and furthermore, particles presumed to be caused by the alkali metal compound will be generated and the transparency will be reduced. deterioration is induced.

In addition, the timing of addition of the metal compound is such that the polycondensation reaction proceeds before the start of the transesterification reaction or esterification reaction, and the intrinsic viscosity reaches 0.
□This is the period until reaching 2. During the transesterification reaction, it is preferable to add the metal compound before the start of the transesterification reaction, since the metal compound can be used as a catalyst for the transesterification reaction. Here, if it is added when the intrinsic viscosity exceeds 0.2, the metal compound will precipitate into the polymer.

No improvement in transparency can be achieved, but rather a decrease in transparency.

By using the raw alkali metal compound specified in the method of the present invention and a metal compound selected from manganese, magnesium, and calcium, transparency is improved and the softening point is lower than when no alkali metal compound is used. It is surprising that the decline can also be suppressed. Furthermore, although there are many known examples of using alkali metal compounds, most of them generate particles and deteriorate transparency, and there are no examples of their use for the purpose of the present invention.

The dicarboxylic acid component used as a raw material for polyester in the present invention is mainly terephthalic acid or its lower alkyl ester, but a portion (usually 20 moles or less) of this acid component is added to phthalic acid or other aromatic dicarboxylic acid components. Acid, adipic acid, sebacic acid, other aliphatic dicarboxylic acids and ester-forming derivatives thereof can be substituted. Ethylene glycol is mainly used as the glycol, but a portion thereof may be replaced with propylene glycol, trimethylene glycol, neopentyl glycol, 1,4-cyclohexanedimetatool, or other diols. Furthermore, chain branching agents such as trimellitic acid and trimesic acid, 5-sulfoisophthalic acid, and other third components can be copolymerized with the polyesters obtained in the present invention to the extent that the purpose of the present invention can be achieved. .

The polymerization catalyst used in the method of the present invention includes antimony,
Germanium and titanium compounds are particularly preferably used, but during the reaction, threads? It is preferable to use a substance that can be solubilized. Moreover, a phosphorus compound can also be used as a coloring inhibitor. Examples of such phosphorus compounds include common phosphorus compounds such as phosphoric acid, phosphoric acid esters such as phosphoric triesters and acidic phosphoric esters, tinous acid, and phosphorous esters. There is no particular limit to the amount of these phosphorus compounds added, but if the amount of phosphorus compounds added is too large, the polymerization rate will decrease, and conversely, if the amount of phosphorus compounds added is too small, the polymerization rate will decrease. There are problems such as coloring, and one piece of polyester obtained is o, 01 to 0.
5 molar ratio is preferred.

Note that dyes, pigments, nucleating agents, and other additives may be added to the polyester of the present invention depending on the purpose. The polyester obtained by the method of the present invention is transparent without haze and has a high softening point, and is particularly useful for obtaining films such as photographic films and magnetic tapes, and stretch-molded bottles. .

Next, the present invention will be specifically explained using Example E.

The color tone of the polymer in the examples was expressed by the b value measured using a color difference meter (Model C!M-20, manufactured by Chikara Machine Co., Ltd.) using the polymer in the form of a chip. What is the intrinsic viscosity of the polymer?

This is a value measured at 25°C using 0-chlorophenol as a solvent. Also, the haze is ASTM-D100!1-
The value was measured from 52#, and the smaller the value, the better the transparency.

Example 1 100 parts of dimethyl terephthalate and 7 parts of ethylene glycol
o parts t 0.09 parts of magnesium acetate.

0.0043 parts of lithium acetate (A/M=0.10),
After adding 0.03 part of antimony trioxide, and adding 0.043 part of trimethyl phosphorylate, a product obtained by transesterification using a conventional method, the temperature was gradually increased and the pressure was reduced to 1.
Finally, polymerization was carried out at 285° C. under reduced pressure of 11111 RHg or less. Four hours after starting the polymerization, the polymer was taken out according to a conventional method and made into chips. The obtained polymer had an intrinsic viscosity of 0.655, a softening point of 260.2°C, a haze of ZO%, a b value of 5.4, and transparency.
The polymer had a good softening point and color tone.

Examples 2-4. Comparative Examples 1 to 3 Transesterification and polymerization reactions were carried out in exactly the same manner as in Example 1, except that the amount of lithium acetate added was changed.

Table 1 shows the properties of the obtained polymer.

As is clear from the above results, when the molar ratio (A/M) of the metal compound defined by the present invention is within the range of the present invention, the haze decreases, transparency improves, and the softening point decreases. Prevention can also be taken.

Example 5 100 parts of dimethyl terephthalate and ethylene glycol, 0.09 parts of calcium acetate, and 0.00 parts of sodium hydroxide.
Add 2 parts (A/M-0,008).

Product t obtained by carrying out transesterification reaction by a conventional method
After adding 0.05 part of phosphoric acid and 0.011 part of germanium dioxide solubilized in a small amount of ethylene glycol, the temperature was gradually increased and the pressure was reduced, and the temperature was finally raised to 285°C + 1
Polymerization was carried out under reduced pressure of less than 200 ml Hg. The intrinsic viscosity of t' +77- obtained 4 hours after the start of polymerization was 0.658, and the value of haze 2 was 2.45. The softening point was 259.0°C.

On the other hand, a polymer obtained by performing transesterification and polycondensation without adding sodium hydroxide had an intrinsic viscosity of 0.641 and a haze of 4.4%.

b value 2.40 Softening point was 257.5°C.

Example 6 A slurry obtained by kneading 865 parts of bis(hydroxyethyl) terephthalate, 865 parts of terephthalic acid, and 57.1 parts of ethysine glycol melted and stored in an esterification reactor at 245 to 250°C was mixed with 5. The esterification reaction was carried out by continuous pumping for 5 hours, and the resulting water was distilled from the top of the rectification column. After the slurry supply was completed, the Nisdell reaction was continued for another 1 hour and 30 minutes to complete the esterification reaction. During this time, the reaction temperature was raised to 255°C. The reaction rate calculated from the acid value and saponification value is 99.3
%Met.

Next, 105 parts of the obtained bis(hydroxyethyl) terephthalate (equivalent to 10 o parts of polyester) was transferred to a polycondensation reactor, and 0.18 parts of magnesium chloride and 0.012 parts of lithium chloride (A/M=0, 16) parts were added. After adding 0.11 parts of dimethyl phosphate and 0.04 parts of antimony trioxide, the reaction temperature was increased from 255°C to 285°C.
The temperature was raised to 1 stage in 60 minutes, and the vacuum level of the 1 stage reaction system was also 7.
The pressure was reduced from 6°NHg to 11aHgt. The mixture was kept at 285° C. and 0.5 to 1101 Hg for 2 hours to complete the polycondensation reaction and obtain a polyester. The polyester has an intrinsic viscosity of 0.655 and a haze of 1.0.
%, b value is 5.4. The softening point was 260.2°C. −
The polymer obtained by the polycondensation reaction without adding lithium chloride had an intrinsic viscosity of 0.631, a haze of 4%, and a
The value is 4.0. The softening point was 258.5°C, which was poor in both haze (transparency) and softening point.

Example 7 100 parts of dimethyl terephthalate and ethylene glycol t
0.05 part of manganese acetate, 0.05 part of potassium methoxide.
After adding 0.002 parts (A/M = 0.14) and carrying out a transesterification reaction using a conventional method, 0.035 parts of triethyl phosphate and 0.03 parts of antimony trioxide were added to the obtained product. A polycondensation reaction was carried out by raising the temperature and reducing the pressure. The obtained polymer had an intrinsic viscosity of 0.615, a haze of 2.0%, a b value of 4.3, and a softening point of 260.3°C. On the other hand, potassium methoxide was added at 0.011 (A/
The intrinsic viscosity of the polymer obtained by adding M = 0.77 parts and carrying out transesterification and polycondensation reactions was 0.610.
Haze coefficient 4.0, b value 5.3. It had a softening point of 260.0 and was inferior in transparency.

Patent applicant: Toshi Co., Ltd.

Claims (1)

[Claims] In the production of polyester from a dicarboxylic acid or its ester-forming derivative containing terephthalic acid as the main component and Dalicol containing ethylene glycol as the main component,
A haze-free polyester characterized by completing a polycondensation reaction in the presence of one or more glycol-soluble metal compounds 8 selected from manganese, magnesium, and calcium and a glycol-soluble alkali metal compound satisfying the following formula: manufacturing method. 0.01≦A/M≦0.5