JPH04345617A - Production of polyester - Google Patents

Abstract

PURPOSE:To produce a polyester at an improved rate of polymerization. CONSTITUTION:A process for producing a polyester consisting mainly of tetraphtalic acid or 2,6-naphthalenedicarboxylic acid and ethylene glycol as starting materials and 0.1-3wt.% particles having a power of adsorbing a metal compound of 10% or above, wherein a magnesium compound and a phosphorus compound are added in such a mounts that the relationships: 1<=Mg<=8 and 0.05<=P/Mg<=0.5 (wherein Mg is the number of moles of the magnesium compound added per 106g of the acid component consisting the polyester, and P is the number of moles of the phosphorus compound added per 106g of the acid component constituting the polyester) are simultaneously satisfied.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing polyester. More specifically, the present invention relates to a method for producing a polyester that improves the polymerization rate of a polyester containing particles that retard the polymerization rate, reduces the amount of terminal carboxyl groups, and also improves electrostatic adhesion.

0002

[Background Art and Problems to be Solved by the Invention] Polyester films, represented by polyethylene terephthalate, have excellent physical and chemical properties, and are used as base films for graphic arts, displays, packaging materials, and magnetic recording media. Widely used in fields such as capacitor derivatives. However, when trying to manufacture a film that takes full advantage of its transparency,
Film runnability is particularly required in terms of process passability in the manufacturing process, post-processing processes such as coating and vapor deposition, and handling of the product itself, but this has not always been fully achieved in the past. . This is often caused by friction and wear caused by high-speed contact between the film and the base material.

Conventionally, it has been known that in order to improve the running properties and abrasion resistance of a polyester film, it is sufficient to appropriately roughen the surface of the film. In order to achieve this, a method has been adopted in which fine particles are present in the raw polyester, and some have been put into practical use.
It is not always possible to satisfy these characteristics to a high degree. For example, when using so-called precipitated particles, which are generated from catalyst residues during polyester production, as fine particles, it is difficult to control the particle amount and particle size, and to prevent the formation of coarse particles. Because they are easily destroyed, they have poor running performance and wear resistance, and are also difficult to recycle.

[0004] Another method, called the addition method, is one in which inert inorganic compound particles such as calcium carbonate, titanium dioxide, calcium phosphate, etc. are added to polyester, and the particles are not destroyed or deformed by stretching and are relatively stable. By providing steep protrusions, runnability is improved, but since such particles have poor affinity with polyester, voids are created around the particles during stretching, resulting in a significant decrease in transparency.
Particles tend to detach from the film surface, resulting in phenomena such as the formation of white powdery substances.

In order to solve this problem, it is known to use silica particles, alumina particles, and titanium oxide particles, which have a relatively good affinity with polyester having reactive groups such as hydroxyl groups (-OH) on the particle surface. However, when such particles are used, the affinity with polyester can be improved, but on the other hand, there is a drawback that the polymerization rate during polyester production is reduced. Although the reason for this is not clear, it is thought that, in the case of silica particles, for example, this is due to the interaction between the silanol groups present on the surface of the particles and the metal compound serving as the polymerization catalyst, such as partially trapping of the metal compound.

[0006]

[Means for Solving the Problems] In view of the above-mentioned circumstances, the present inventors have made extensive studies and found that a specific amount of magnesium compound and phosphorus are used to produce polyester containing specific particles that retard the polymerization rate. It was discovered that the polymerization rate could be improved by using a compound, and the present invention was completed.

That is, the gist of the present invention is to use terephthalic acid or 2,6-naphthalene dicarboxylic acid and ethylene glycol as main starting materials, and to obtain a metal compound adsorbent having a metal compound adsorption capacity of 10.
% or more of particles by weight of 0.1 to 3% by weight, the production of a polyester characterized by adding a magnesium compound and a phosphorus compound that simultaneously satisfy the following formulas (1) and (2). It lies in the method.

1≦Mg≦8 (1) 0.05
≦P/Mg≦0.5...(2) (In the above formula, Mg is the number of moles of the magnesium compound per 106 g of the acid component constituting the polyester, and P is the mole of the phosphorus compound per 106 g of the acid component constituting the polyester. The present invention will be described in more detail below.

[0009] The polyester as used in the present invention refers to a polyester obtained using a lower alkyl ester of an aromatic dicarboxylic acid such as dimethyl terephthalate or dimethyl 2,6-naphthalene dicarboxylate and ethylene glycol as main starting materials. It may also contain other third components. In this case, as the dicarboxylic acid ester component, one or more types of esters such as isophthalic acid, terephthalic acid, 2,6-naphthalenedicarboxylic acid, adipic acid, and sebacic acid can be used in combination.

[0010] As the glycol component, one or more of diethylene glycol, propylene glycol, butanediol, 1,4-cyclohexanedimethanol, neopentyl glycol, etc. can be used in combination. In any case, the polyester of the present invention refers to a polyester in which 80% or more of repeating structural units have ethylene terephthalate units or ethylene-2,6-naphthalate units.

The object of the present invention is a case where a specific amount of particles having a metal compound adsorption ability in a specific range is present.
The metal compound adsorption ability herein refers to the ability to adsorb an antimony (Sb) compound used as a polymerization catalyst, and was measured under the following conditions.

That is, antimony trioxide and ethylene glycol are mixed and heated to produce 200p of Sb metal.
An ethylene glycol solution containing pm was prepared, then 2% by weight of particles were added to the solution, and the mixture was heated at 180°C under a nitrogen atmosphere.
After stirring for 3 hours, the mixture was cooled to room temperature, the particles and ethylene glycol solution were completely separated using a centrifuge, and the amount of Sb compounds in the supernatant ethylene glycol was determined by atomic absorption spectrometry. The amount of Sb compound adsorbed by the particles is the value obtained by subtracting the Sb compound in ethylene glycol from the charged amount, and the metal compound adsorption capacity is defined as the following formula.

[0013]

[0014] The present invention targets particles in which the adsorption amount of such metal compounds is 10% or more, and the effects of the present invention are maximized especially when the adsorption amount of the metal compound is 15% or more. Ordinary inorganic or organic particles have a metal compound adsorption capacity of 1% or less, but particles carrying reactive groups such as hydroxyl groups in order to improve affinity with polyester have this value of, for example, 10%. ~70%. Typical examples include specific aluminum oxide, silicon oxide, and titanium oxide, but in the present invention, as long as the particles are within this range, it does not matter whether the particles have been surface treated or not, and whether they are organic or inorganic. do not have.

A feature of the present invention is that the polycondensation reaction is carried out under certain specific conditions. That is, when producing polyester, a polymerization catalyst such as an antimony compound or a germanium compound is generally used, but in the present invention, 1 to 8 mol, preferably 3 to 8 mol, of magnesium element is used per 106 g of the acid component constituting the polyester. The magnesium compound is added in an amount of 7 mol, more preferably 5 to 7 mol.

If the amount of the magnesium compound is less than 1 mol, the polymerization rate will be extremely slow, and the resulting polyester will have a high specific resistance value when melted, resulting in a polyester with poor film-forming properties. On the other hand, if the amount of magnesium exceeds 8 mol, the color tone of the resulting polyester may be impaired or the thermal stability may be reduced. The magnesium compound used in the present invention may be any of oxides, chlorides, hydrides, carbonates, alcoholates, carboxylates, etc., but carboxylates, particularly magnesium acetate, are preferably used.

Furthermore, the catalyst system used in the present invention is
Molar ratio of phosphorus compound and magnesium compound (P/Mg)
is set to 0.05 to 0.5, preferably 0.1 to 0.4. When P/Mg is less than 0.05, the polymerization rate is delayed,
Furthermore, the resulting polymer has poor thermal stability and poor color tone, which is not preferable. When P/Mg exceeds 0.5, the effect of improving the polymerization rate is small. As the phosphorus compound used in the present invention,
From the viewpoint of preventing reaction with the magnesium compound used as a transesterification catalyst, acidic phosphoric acid esters such as methyl acid phosphate, ethyl acid phosphate, and butyl acid phosphate, or phosphoric acid triphosphates such as trimethyl phosphate, triethyl phosphate, and tributyl phosphate are used. Esters are preferred, but are not particularly limited thereto. Among these, ethyl acid phosphate is particularly preferred.

[0018] Furthermore, as the polymerization catalyst used in the present invention,
Antimony compounds are preferred, and the amount thereof is usually 0.2 to 4 mol, preferably 1.6 to 3.2 mol, based on the acid component constituting the polyester. If the amount of the antimony compound is less than 0.2 mol, no improvement in the polymerization rate can be expected even if the method of the present invention is employed. Moreover, if it is used in an amount exceeding 4 moles, the antimony compound will precipitate during polymerization and become coarse foreign matter, which is not preferable.

In the present invention, the esterification reaction of the magnesium compound and the phosphorus compound has been substantially completed, and
The antimony compound may be added when the reaction rate reaches 80% or more, preferably 90% or more, and the antimony compound may be added before the start of the esterification reaction.

[0020]

[Examples] The present invention will be explained in more detail below with reference to Examples, but the present invention is not limited to the following Examples unless the gist thereof is exceeded. In addition, the measurement methods and definitions of various physical properties and characteristics in Examples are as follows. Furthermore, in Examples and Comparative Examples, "parts" indicate "parts by weight." (1) Average particle size and particle size distribution Centrifugal sedimentation particle size distribution analyzer manufactured by Shimadzu Corporation (SA-CP3
The integrated volume fraction 50 in the equivalent spherical distribution measured with
% particle size (diameter) was taken as the average particle size.

(2) 1 g of limiting viscosity polymer is mixed with phenol/tetrachloroethane = 50
/50 (weight ratio) dissolved in 100 ml of mixed solvent, 30
．． Measured at 0°C. (3) Terminal carboxyl group concentration A. Conix method (makromol.chem.
26, 226 (1958)).

(4) Melting thermal stability 10 g of polymer was placed in a glass test tube with an internal volume of 50 ml, and after drying at 160° C. for 2 hours under high vacuum, the pressure was restored to 100 mmHg with nitrogen gas, and the glass test tube was melted. After sealing, 29
Heat treatment was performed at 0° C. for 1 hour, the intrinsic viscosity before and after the heat treatment was measured, and the intrinsic viscosity retention rate was determined from the following formula. The obtained limiting viscosity retention rate was used as a measure of thermal stability.

(5) Color tone Color analyzer TC-1800M manufactured by Tokyo Denshoku Co., Ltd.
R2. Using a mold, it was measured according to the method of JIS Z-8722, and the b value at that time was used as a standard for color tone. (6) Specific resistance of polyester during melting British Journal of Applied Physics (Brit. J. Appl. Phys.) No. 1
The method described in Vol. 7, pp. 1149-1154 (1966) was followed. However, the temperature at the time of melting of the polymer was 290° C., and the value immediately after applying a direct current of 3000 V was taken as the specific resistance at the time of melting.

Example 1 An esterification reaction was carried out by reacting 100 parts of bis-(β-hydroxyethyl) terephthalate oligomer, 87 parts of terephthalic acid and 42 parts of ethylene glycol at 250° C. under normal pressure. 4 hours after the start of the reaction, the esterification rate was 9.
7% polyester oligomer was obtained. On the other hand, 10 silica particles with an average particle size of 0.9 μm and a metal compound adsorption capacity of 39%
and 90 parts of ethylene glycol were mixed and stirred to prepare a slurry, and 10 parts of this slurry was added to 103 parts of the above polyester oligomer (equivalent to 100 parts of polyester), followed by 0.012 parts of ethyl acid phosphate (
Then, 0.088 part (4.11 mol, P/Mg=0.2) of magnesium acetate tetrahydrate and 0.033 part (2.26 mol) of antimony trioxide were added. While raising the temperature from 250°C to 285°C over 120 minutes, the pressure was simultaneously reduced from 760mmHg to 1mmHg, and a polycondensation reaction was carried out under the same conditions. After 4 hours and 9 minutes, a polyester with an intrinsic viscosity of 0.635 was produced. Obtained.

Example 2 Example 1 except that the amount of ethyl acid phosphate was changed to 0.023 parts (1.65 mol).
A polycondensation reaction was carried out in the same manner as above. Example 3 In Example 1, the amount of magnesium acetate tetrahydrate was reduced to 0.
A polycondensation reaction was carried out in the same manner as in Example 1, except that the amount of ethyl acid phosphate was changed to 132 parts (6.17 mol) and 0.017 parts (1.23 mol).

Example 4 In Example 1, instead of using silica particles, the primary particle size was 0.
A polycondensation reaction was carried out in the same manner as in Example 1, except that alumina particles having a diameter of 0.018 μm and a metal compound adsorption amount of 21% were used. Example 5 A polycondensation reaction was carried out in the same manner as in Example 4, except that the amount of ethyl acid phosphate was changed to 0.023 parts (1.65 moles).

Comparative Example 1 A polycondensation reaction was carried out in the same manner as in Example 1 except that no magnesium compound was added. Comparative Example 2 A polycondensation reaction was carried out in the same manner as in Example 1, except that the amount of ethyl acid phosphate was changed to 0.058 parts (4.11 moles). Comparative Example 3 Example 1 except that the amount of ethyl acid phosphate was changed to 0.058 part (4.11 mol) and the amount of antimony trioxide was changed to 0.040 part (2.74 mol).
A polycondensation reaction was carried out in the same manner as above.

Comparative Example 4 A polycondensation reaction was carried out in the same manner as in Example 4, except that no magnesium compound was added. Comparative Example 5 A polycondensation reaction was carried out in the same manner as in Example 4, except that the amount of ethyl acid phosphate was changed to 0.058 parts (4.11 moles). Comparative Example 6 Example 4 except that the amount of ethyl acid phosphate was changed to 0.058 part (4.11 mol) and the amount of antimony trioxide was changed to 0.040 part (2.74 mol).
A polycondensation reaction was carried out in the same manner as above. The results obtained above are summarized in Table 1 below.

[0029]

[Table 1]

As shown in Tables 1 and 2, the polymerization time of Examples 1 to 5, which are within the scope of the present invention, is approximately 1 hour longer than that of Comparative Examples 1 to 6, which are conventional catalyst systems. The properties of the resulting polyester, such as terminal carboxyl groups, thermal stability, and color, are also good, making the polymer extremely useful for magnetic recording media, graphic arts, displays, and packaging films.

[0031]

According to the present invention, the polymerization rate can be significantly improved, and when the obtained polyester is made into a film, the properties are sufficient and it can be applied to various uses, and its industrial value is high.

Claims (1)

[Claims] Claim 1: Particles containing terephthalic acid or 2,6-naphthalene dicarboxylic acid and ethylene glycol as main starting materials and having a metal compound adsorption capacity of 10% or more.
．． A method for producing a polyester, which comprises adding a magnesium compound and a phosphorus compound that simultaneously satisfy the following formulas (1) and (2) when producing a polyester containing 1 to 3% by weight. 1≦Mg≦8 (1) 0.05≦P/Mg≦0.5 (2) (In the above formula, M
(g represents the number of moles of the magnesium compound relative to 106 g of the acid component constituting the polyester, and P represents the number of moles of the phosphorus compound relative to 106 g of the acid component constituting the polyester)