JPH0637551B2 - Polyester manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION "Industrial field of application" The present invention provides a polyester production method, particularly good electrostatic adhesion to a cooling drum at the time of melt film formation, which reduces minute foreign matters when formed into a film. The present invention relates to a method for directly producing a polyester having a high softening point and little coloring.

"Prior Art" Polyethylene terephthalate is excellent in mechanical strength and chemical stability, and is widely used for photographic use, magnetic tape use, packaging use, condenser use, etc. as well as fibers.

The production method of polyethylene terephthalate is DMT using dimethyl terephthalate and ethylene glycol as raw materials.
And the direct weight method using terephthalic acid and ethylene glycol as raw materials are well known. Conventionally, polyester films were often manufactured by the DMT method, but in recent years, each manufacturer is switching to the direct weight method in order to reduce the manufacturing cost.

Polyester film is usually obtained by melt-extruding with an extruder and then uniaxially or biaxially stretching. The adhesiveness between the cooling drum and the polyester sheet during melt-extrusion is important for determining the flatness of the film surface. This is a very important factor, and in order to improve this, an electrode for applying a high voltage is provided between the extruder die and the cooling drum to generate an electric charge in the unsolidified polyester and enhance the adhesion with the cooling drum. (Hereinafter referred to as electrostatic adhesion) is known. (For example, Japanese Examined Patent Publication No. 37-6142) However, if the film-forming speed is increased and the film productivity is increased, the amount of charges deposited on the unsolidified sheet decreases,
Eventually, the adhesion with the cooling drum deteriorates and the surface has a crease shape,
Pinhole-like unevenness is created. The film obtained by stretching such a sheet has poor surface flatness and cannot be used particularly for photography.

This phenomenon is particularly prominent in the direct weight polyester which does not use a metal catalyst in the esterification reaction, as compared with the DMT polyester which uses a large amount of a metal compound as a catalyst for the transesterification reaction.

Attempts have also been made to add an alkali metal compound or an alkaline earth metal compound to the production process of polyester to increase the amount of charge deposition and improve electrostatic adhesion. (For example, JP-A-51-70269) However, the addition of a large amount of such metals in the polyester causes generation of fine agglomerated foreign matters, by-products of ether bonds that lower the softening point of the polymer, and formation of the polymer. Coloring is likely to occur, and it is difficult to use the polyester obtained by this method as a raw material for a polyester film having a quality of a level practical for photography.

As a means for solving such a problem, a technique of adding a phosphorus compound and an alkali metal and / or alkaline earth metal compound in addition to a compound of a metal such as magnesium or manganese (for example, JP-A-55-55). 84322, JP-A-55-89329), and tertiary amines and quaternary ammonium hydroxide compounds in addition to compounds of metals such as magnesium and manganese, specifically triethylamine, tributylamine, dimethylaniline, pyridine and quinoline. ,
Tetraethylammonium hydroxide, tetrabutylammonium hydroxide, triethylbenzylammonium hydroxide, etc. and phosphorus compounds, specifically, trimethylphosphite, phosphoric acid mono- or diethyl ester, phosphoric acid, triethylphosphite, diethylphosphite , Phosphorous acid, etc.
And the technique of adding (for example, JP-A-55-11542
5) is also disclosed.

In particular, the quality as a raw material for a photographic film for a printing original plate or a microfilm, which requires a high degree of coloring and a small amount of foreign matter, has not been completely satisfactory.

[Problems to be Solved by the Invention] The inventors of the present invention have made earnest studies on the above-mentioned problems, and as a result, despite containing a relatively large amount of a metal compound, there are few fine foreign matters and a high softening point. It was possible to provide a method for producing a polyester which has a low degree of coloring and is excellent in electrostatic adhesion during melt film formation, and is particularly suitable as a raw material for a photographic film for a printing original plate or a microfilm.

"Means for Solving Problems" The present invention provides a low-polymer polyester by directly reacting a difunctional carboxylic acid mainly containing terephthalic acid with a glycol mainly containing ethylene glycol. When a polyester low polymer is polycondensed in the presence of a polycondensation catalyst to produce polyester, a glycol-soluble magnesium compound, a glycol-soluble manganese compound or a glycol-soluble zinc compound and 1,8-diazabicyclo (5,4,4) are used. 0) A method for producing a polyester, which comprises coexisting undecene-7 and a phosphorus compound.

The present invention is also applicable to polyesters containing 20% or less of a copolymerization component other than polyethylene terephthalate. The copolymerization component includes, as the dicarboxylic acid component, an aromatic dicarboxylic acid such as isophthalic acid, an alicyclic dicarboxylic acid such as cyclohexanedicarboxylic acid, and an aliphatic dicarboxylic acid such as adipic acid and sebacic acid.

Examples of the glycol component that can be a copolymerization component include diethylene glycol, triethylene glycol, butanediol, cyclohexamethanediol, and xylylene glycol.

Next, the production method will be outlined according to the present invention by taking polyethylene terephthalate as an example.

The present invention can be applied to any of the batch method, the semi-continuous method, and the continuous method, but the batch method will be described.

Terephthalic acid and ethylene glycol are put in a slurry form before being put into the esterification reaction can or in the esterification reaction can. The molar ratio of terephthalic acid and ethylene glycol charged is preferably 1: 1.05 to 1: 2.5.

Then, the temperature of the reaction vessel is raised and the slurry is heated to start the esterification reaction of terephthalic acid and ethylene glycol. The reaction is performed while stirring the system, and the temperature is
240 to 280 ° C is preferred. The pressure of the reaction system is operated under normal pressure or under pressure, and is preferably 5 kg / cm ² G or less. The esterification reaction proceeds even without using a catalyst. The reaction proceeds while removing by-product water from the esterification reaction from the distillation column attached to the reactor. When the esterification reaction is complete, water distilling stops.

Subsequently, the polycondensation reaction step is started, but before that, foreign matters in the reaction solution can be removed by passing through a filter. The polycondensation reaction is performed under reduced pressure at 270 to 290 ° C. while removing ethylene glycol, which is a by-product of the condensation reaction, outside the reaction system. In order to avoid bumping of the reaction liquid, it is preferable to gradually reduce the initial pressure. The final degree of vacuum usually adopted is 1 to 0.01 mmHg. The polycondensation reaction catalyst is preferably added before the start of the polycondensation reaction step.

Examples of the glycol-soluble magnesium compound, manganese compound and zinc compound used in the present invention include organic carboxylates such as acetate, oxalate and benzoate, halides and hydroxides.

Specifically, magnesium acetate, manganese acetate, zinc acetate, magnesium oxalate, manganese oxalate, zinc oxalate, magnesium benzoate, manganese benzoate, zinc benzoate, magnesium chloride, manganese chloride, zinc chloride, magnesium bromide. , Manganese bromide, zinc bromide, magnesium hydroxide and the like.

As the phosphorus compound, phosphorous acid, phosphoric acid and / or their esters can be used.

Specific examples of the phosphorus compound include phosphorous acid, phosphoric acid, trimethylphosphonate, triethylphosphonate, triphenylphosphonate, phosphoric acid, and mono- or diesters of phosphorous acid.

As the polycondensation reaction catalyst, known antimony compounds, germanium compounds and titanium compounds may be used alone or in combination of two or more.

Specific examples of the polycondensation reaction catalyst include antimony trioxide,
Examples thereof include germanium dioxide and titanium alkoxide.

Above magnesium compounds, manganese compounds and /
Alternatively, a zinc compound and 1,8-diazabicyclo (5,4,4
0) Undecene-7 and the phosphorus compound are from the time when the esterification reaction of the difunctional carboxylic acid containing terephthalic acid and the glycol containing ethylene glycol is substantially completed to the time when the polycondensation reaction is started. It is preferable to add it.

Further, the polycondensation reaction catalyst can be added at any time before the polycondensation reaction starts.

A glycol-soluble magnesium compound used in the present invention,
The amount of manganese compound or zinc compound added is 1 per 1000 kg of polyester as the total amount of these metal atoms.
To 10 g atoms are preferred.

The addition amount of the phosphorus compound used in the present invention is polyester 1
The phosphorus atom per 000 kg is preferably 0.5 to 3 times the total amount of metal atoms from the glycol-soluble magnesium compound, manganese compound and zinc compound.

1,8-diazabicyclo (5,4,0) used in the present invention
The amount of undecene-7 added is preferably 0.2 to 8 mol per 1000 kg of polyester.

Example 1 In an esterification reaction can, terephthalic acid (TPA) 100 was added.
Part, ethylene glycol (EG) 59.8 parts and polycondensation catalyst antimony trioxide 0.029 parts were charged, and the temperature was raised while sufficiently stirring the contents to form a slurry, and by-produced water was distilled into a distillation column. While removing from the reaction temperature 245 ℃
Was reached. The reaction was continued for about 4 hours as it was, and after it was confirmed that the by-product of water had substantially stopped, the low polymer of polyester which was the reaction product was transferred to a polycondensation reaction vessel and magnesium acetate tetrahydrate was added to 051 parts, 0.008 parts of 1,8-diazabicyclo (5,4,0) undecene-7 and 0.022 parts of phosphoric acid were added. After leaving it as it is for 10 minutes with stirring, gradually reduce the pressure of the system to 2
Polycondensation reaction was carried out at 75 to 280 ° C. for about 4 hours to obtain polyester. The intrinsic viscosity (I
When V) was measured, IV = 0.64 (phenol /
Tetrachloroethane = 1/1 (weight ratio) in a solvent at 25 ° C
Measurement). Further, when the b value was measured with a colorimetric color difference meter ND-101D type (manufactured by Nippon Denshoku Industries Co., Ltd.) in order to see yellowness, it was 3.6. The softening point measured by a falling-ball type softening point measuring device was 260 ° C. When this was applied to a melt extruder to form a film, a DC voltage of 5 KV was applied between the extruder die and the cooling drum, and the sheet polyester was excellent in adhesion with the cooling drum and had excellent flatness. was gotten. Furthermore, when this sheet-shaped polyester was biaxially stretched and a minute foreign substance was observed as a film having a thickness of 100 μm under an optical microscope, very few substances having a thickness of 20 μm or more were found. The polyester film was sufficiently usable as a photo for a printing original plate and a micro film.

Example-2 In place of the magnesium acetate of Example-1, 0.058 part of manganese (II) acetate tetrahydrate was used. A film was formed in the same manner as in Example-1, and there was no problem in quality for photographic film.

The characteristic values were measured in the same manner as in Example-1, and the results are shown in Table 1.

Example-3 In place of the phosphoric acid of Example-1, 0.073 part of triphenyl phosphonate was added. A film was formed in the same manner as in Example-1, and there was no problem in quality for photographic film.

The characteristic values were measured in the same manner as in Example-1, and the results are shown in Table 1.

Comparative Example-1 Example-1 and 1,8-diazabicyclo (5,4,0)
The same operation was performed except that undecene-7 was not added. The polycondensation reaction took about 4 hours. The obtained polyester had IV = 0.65. The b value of the pellet was 3.6, which was almost the same as in Example-1,
The softening point was 257 [deg.] C., which was clearly lower than that of Example-1, and was unsuitable for photographic film due to insufficient strength. The voltage applied to the melt extruder is 5 KV, and the effect is seen.
The flatness of the obtained film was excellent.

The characteristic values were measured in the same manner as in Example-1, and the results are shown in Table 1.

Comparative Example-2 The same operation as in Example-1 was performed, except that magnesium acetate was not added. B value of pellet is 3.3
The yellowness was weaker than that of Example-1. Using this pellet, a film was formed under the same conditions as in Example-1, but the electrostatic adhesion was poor, and the sheet had a tatami mat-shaped unevenness, and the unevenness remained even after stretching treatment, resulting in poor flatness. Only the film was obtained, and it could not be used for photography.

The characteristic values were measured in the same manner as in Example-1, and the results are shown in Table 1.

Comparative Example-3 In place of 1,8 diazabicyclo (5,4,0) undecene-7 of Example-1, tetraethylammonium hydroxide was added. The film was formed under the same film forming conditions as in Example-1, but it was used as an X-ray photographic film due to the large amount of minute foreign matter, but when used for a printing original plate photograph or a micro film, they were regarded as noise of recorded information. I couldn't use it because it appeared.

The characteristic values were measured in the same manner as in Example-1, and the results are shown in Table 1.

Claims (1)

[Claims] 1. A bifunctional carboxylic acid containing terephthalic acid as a main component and a glycol containing ethylene glycol as a main component are directly reacted to form a polyester low polymer, and the polyester low polymer is used as a polycondensation catalyst. When a polyester is produced by polycondensation in the presence of, a glycol-soluble magnesium compound, a glycol-soluble manganese compound or a glycol-soluble zinc compound, 1,8-diazabicyclo (5,4,0) undecene-7 and a phosphorus compound are added. A method for producing polyester, which is characterized by coexistence.