JP2842982B2 - Polyester production method - Google Patents

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 a polyester, and more particularly, to a method for producing a polyester which is excellent in dry heat deterioration resistance and excellent in surface flatness as a film.

[0002]

2. Description of the Related Art When a biaxially oriented polyester film is used as a base film for high-density recording represented by, for example, a vapor-deposited video tape, flatness of the film surface is particularly required. In order to achieve this flatness, it is necessary not to have not only coarse projections but also relatively small projections on the film surface.

[0003] The cause of these film surface protrusions is that a catalyst, particularly an antimony compound, added during the production of the polyester is precipitated in the polyester. When an antimony compound is used, the polymerization rate is high, and the resulting polyester has excellent properties such as thermal stability, terminal carboxyl group content, and softening point, but has the drawback of producing a precipitate in the polyester as described above. Have.

[0004] In addition to the above-mentioned antimony compounds, examples of polyester polymerization catalysts include, for example, JP-B-47-157.
No. 03, JP-B-47-16193, JP-B-4
In JP-A-7-42756, a germanium compound is
JP-A-48-31293, JP-A-52-3399
No. 6 discloses the use of a titanium compound. However, when a germanium compound is used, there is no precipitate such as an antimony compound, but since the side reaction during the polymerization reaction is large, the softening point of the obtained polyester is low, and when the film is formed, the mechanical properties of the film are reduced. There is a disadvantage that the target strength is reduced. Further, when a titanium compound is used, the polymerization rate is extremely high, and a precipitate such as an antimony compound is not formed, but there is a disadvantage that the thermal stability of the obtained polyester is deteriorated.

On the other hand, improving the thermal stability by adding a phosphorus compound during the production of polyester is a general technique, but is not yet an optimized technique.
Further, the phosphorus compound has a problem that it reacts with most of the polymerization catalyst to lower the activity of the catalyst or generate a precipitate. In particular, a titanium compound has a large degree of deactivation by a phosphorus compound.

Further, when manufacturing a base film for vapor deposition video, it is difficult to ensure the running property and winding property of the film because the film surface is required to be ultra-flat. For this reason, it is common to apply a slippery treatment (such as in-line coating) to the film surface.
(−220 ° C.) may need to be set higher (230 to 240 ° C.). At this time, when the film is stopped in the heat fixing device (stenter) due to a film breakage or the like, the thin film polyester is subjected to dry heat treatment at a high temperature, so that the deterioration proceeds in a surprisingly short time, and the film becomes fine. It turned out to be powdery and adhered to the inside of the stenter, and it was found that there was a problem that it became involved in foreign matter during the subsequent film formation. This does not occur when an antimony compound is used as a catalyst, but occurs when a titanium compound or a germanium compound is used, and is particularly remarkable for a titanium compound.

[0007]

SUMMARY OF THE INVENTION In view of the above circumstances, the present inventors have made intensive studies to produce a polyester having excellent resistance to dry heat deterioration and excellent surface flatness as a film, and as a result, the present invention has been achieved. .

[0008]

That is, the present invention relates to a method for producing a polyester by reacting an aromatic dicarboxylic acid and / or an ester-forming derivative thereof with a glycol to prepare an optional step until the reaction is completed. Wherein a magnesium compound, a calcium compound, a titanium compound and a phosphorus compound are added so as to satisfy the following formulas (1) to (4).

[0009]

2.1 <(Mg + Ca) <5.1 (1) 1.0 <(Mg / Ca) <6.0 (2) 1.6 <(Mg + Ca) / P <7.0 (3) 0 <Ti ≦ 0.15 (4) (In the above formula, Mg is the acid component 10 of the magnesium element.
⁶ g per mole, Ca is the number of moles of calcium element per 10 ⁶ g of the acid component, Ti is the mole number of titanium element per 10 ⁶ g of the above acid component, and P is 10 ⁶ g of the above acid component of the phosphorus element. The number of moles per unit is shown. )

In the present invention, examples of the aromatic dicarboxylic acid include terephthalic acid, naphthalenedicarboxylic acid, isophthalic acid, diphenyl ketone dicarboxylic acid, and anthracene dicarboxylic acid. Such aromatic dicarboxylic acids may be used alone or in combination of two or more. Further, a part of the aromatic dicarboxylic acid (for example, 30 mol% or less, preferably 20 mol% or less) is converted to another dicarboxylic acid, for example, an aliphatic dicarboxylic acid such as adipic acid or sebacic acid, or cyclohexane-1,4-dicarboxylic acid. May be substituted with an alicyclic dicarboxylic acid or the like.

Examples of the ester-forming derivative of the aromatic dicarboxylic acid include lower alkyl esters such as dimethyl ester and aryl esters such as diphenyl ester. The ester-forming derivatives of other dicarboxylic acids are the same as the ester-forming derivatives of aromatic dicarboxylic acids.

In the present invention, examples of the glycol include polymethylene glycol having 2 to 10 carbon atoms such as ethylene glycol, trimethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, decamethylene glycol and the like, and cyclohexanedimethanol. And alicyclic diols. Such glycols may be used alone or in combination of two or more. Part of the glycol (for example, 30 mol% or less, preferably 20 mol% or less)
May be substituted with, for example, an aromatic diol such as hydroquinone, resorcin, 2,2-bis (4-hydroxyphenyl) propane, or an aliphatic diol having an aromatic ring such as 1,4-dihydroxydimethylbenzene.

As understood from the above, the polyester in the present invention is a polyester containing an aromatic dicarboxylic acid as a main acid component and an aliphatic glycol as a main glycol component. Such polyesters are substantially linear and have film forming properties, especially film forming by melt molding.

As the polyester, those containing alkylene terephthalate and / or alkylene naphthalate as a main component are preferred.

Among such polyesters, in particular, polyethylene terephthalate, polyethylene-2,6-naphthalate and, for example, 8
A copolymer in which 0 mol% or more is terephthalic acid and / or 2,6-naphthalenedicarboxylic acid and 80 mol% or more of all glycol components is ethylene glycol is preferable. At that time, as long as the surface flatness and the dry heat deterioration property are not impaired, the aromatic dicarboxylic acid other than terephthalic acid and / or 2,6-naphthalenedicarboxylic acid should be 20 mol% or less of all the acid components. And aliphatic dicarboxylic acids such as adipic acid and sebacic acid, and alicyclic dicarboxylic acids such as cyclohexane-1,4-dicarboxylic acid. In addition, 20 mol% or less of the total glycol component can be the above-mentioned glycols other than ethylene glycol, for example, aromatic diols such as hydroquinone, resorcinol, 2,2-bis (4-hydroxyphenyl) propane, and 1,4. An aliphatic diol having an aromatic ring such as dihydroxydimethylbenzene,
Polyethylene glycol, polypropylene glycol,
Polyalkylene glycol (polyoxyalkylene glycol) such as polytetramethylene glycol can be used.

The polyester in the present invention includes:
As long as the effects of the present invention are not impaired, components derived from oxycarboxylic acids such as aromatic oxyacids such as hydroxybenzoic acid and aliphatic oxyacids such as ω-hydroxycaproic acid may be used as dicarboxylic acid components and oxycarboxylic acid components. Can be copolymerized or bonded at 20 mol% or less based on the total amount of

Further, the polyester in the present invention has a trifunctional amount in an amount in the range of being substantially linear and, for example, in an amount of 2 mol% or less based on the total acid components, as long as the effects of the present invention are not impaired. The above polycarboxylic acids or polyhydroxy compounds, for example, trimellitic acid, pentaerythritol and the like can be copolymerized.

Further, the polyester in the present invention includes:
If necessary, additives such as a lubricant, a pigment, a dye, an antioxidant, a light stabilizer, and a light-shielding agent (for example, carbon black, titanium oxide, etc.) may be added as long as the surface flatness and the dry heat deterioration property are not impaired. Can be contained.

In the present invention, polyester is produced by reacting the above-mentioned aromatic dicarboxylic acid and / or its ester-forming derivative with glycol and, for example, transesterifying dimethyl ester of terephthalic acid with ethylene glycol. At that time, the transesterification catalyst
The magnesium compound and the calcium compound soluble in the reaction system are expressed as the number of moles of the element per 10 ⁶ g of the acid component.
A total of 2.1 to 5.1 mol is added. If the total amount of the calcium element and the magnesium element exceeds 5.1 mol, the surface flatness is deteriorated when formed into a film due to the influence of precipitated particles due to the catalyst residue. 1
If it is less than 10, not only the transesterification reaction will be insufficient, but also the subsequent polymerization reaction will be unfavorably slow.

The molar ratio of the amount of the magnesium element to the calcium element is preferably 1.0 to 6.0. Particularly preferably, it is in the range of 1.1 to 2.5. If the molar ratio exceeds 6.0 or less than 1.0, the surface flatness deteriorates when formed into a film under the influence of precipitated particles due to catalyst residues.

Next, in order to deactivate a part of the transesterification catalyst, a phosphorus compound is added when the reaction is substantially completed. The total amount of the compound added is 1.6 to 7.0 in terms of the molar ratio of the elements.
Is preferred. Particularly preferably, it is in the range of 3.2 to 6.0. If the molar ratio exceeds 7.0, the surface flatness deteriorates when formed into a film due to the effect of precipitated particles due to the catalyst residue, which is not preferable. On the other hand, if the molar ratio is less than 1.6, calcium having polymerization activity remains as a compound and a magnesium compound. Is decreased, and the polymerization reaction is prolonged substantially, and the productivity is lowered, which is not preferable.

[0022] While further adding a titanium compound as a main catalyst for the polymerization reaction, the amount the acid component 10 ⁶ g equivalents have enough of
The number of moles of the element is preferably 0.15 mol or less. If the addition amount exceeds 0.15 mol, if the film breaks during the heat setting of the film forming, the dry heat deterioration is large, which is not preferable. If this amount is 0.15 mol or less, there is no problem with dry heat deterioration, and an appropriate amount which does not impair the productivity of the polyester may be added, and is preferably in the range of 0.05 to 1.5 mol.

Even in the direct esterification method which does not require a transesterification catalyst, the amount of each compound added must be within the above range in order to ensure surface properties, resistance to dry heat deterioration, and the rate of polymerization reaction. is there.

The calcium compound and the magnesium compound used in the present invention are, for example, oxides, chlorides, carbonates, carboxylate salts and the like, and are not particularly limited. Particularly preferred are acetates, ie, calcium acetate and magnesium acetate. Examples of the phosphorus compound include trimethyl phosphate, triethyl phosphate, tri-n-butyl phosphate, phosphoric acid, and the like. Preferably it is trimethyl phosphate.

Examples of the titanium compound include titanium tetrabutoxide and titanium trimellitate.

In the present invention, the timing of adding the above-mentioned catalyst is not particularly limited, but preferably, the timing of adding the calcium compound and the magnesium compound is such that the intrinsic viscosity of the reaction system reaches 0.2. In the transesterification method, both compounds are added prior to the start of the transesterification reaction, and can be used as a transesterification catalyst, which is preferable. The order of addition may be such that both compounds are added simultaneously or separately. On the other hand, the phosphorus compound, after the transesterification reaction or esterification reaction is substantially completed,
It is added until the intrinsic viscosity reaches 0.2. Further, the titanium compound is added at an arbitrary time before the intrinsic viscosity reaches 0.3 after the lapse of 10 minutes or more after the addition of the phosphorus compound. Atmosphere in the reaction system upon addition may be the under previous atmospheric pressure to start the polycondensation reaction, but it may also be a reduced pressure after the start of the polycondensation reaction.

As the conditions for the transesterification reaction, esterification reaction, polycondensation reaction and the like, conventionally known conditions can be adopted. The polyester obtained preferably has an intrinsic viscosity of about 0.4 to about 0.9 as measured at 35 ° C. as a solution in o-chlorophenol.

The polyester of the present invention has, for example, a melting point (T
m: ° C.) to (Tm + 70) ° C. to extrude the polyester to obtain an unstretched film having an intrinsic viscosity of 0.35 to 0.9 dl / g, and the unstretched film is uniaxially (longitudinal or transverse). The film is stretched at a temperature of (Tg-10) to (Tg + 70) ° C. (however, Tg: glass transition temperature of polyester) at a magnification of 2.5 to 5.0 times, and then in a direction perpendicular to the stretching direction (first-stage stretching is In the case of the longitudinal direction, the second-stage stretching is in the transverse direction) and the film is stretched at a temperature of Tg (° C.) − (Tg + 70) ° C. at a magnification of 2.5 to 5.0 times to form a biaxially stretched film. You can do it. In this case, the area stretching ratio is preferably 9 to 22 times, more preferably 12 to 22 times. The stretching means may be either simultaneous biaxial stretching or sequential biaxial stretching.

Further, the obtained film is (Tg + 70)
It can be heat-set at a temperature of ° C to Tm (° C). For example, in a polyethylene terephthalate film, 2
It is preferable to heat set at 00 to 240 ° C. The heat fixing time is, for example, 1 to 60 seconds.

Although it is not clear why the biaxially stretched film obtained from the polyester of the present invention has excellent surface flatness and resistance to drying heat deterioration, it is supposed that there is no antimony-induced precipitate in the polyester due to the antimony compound free. In addition, the balance between the addition amounts of the calcium compound and the magnesium compound and the addition amount of the phosphorus compound secures the flatness of the film, and reduces the amount of the titanium compound added by leaving the polymerization activity of the calcium compound and the magnesium compound. It is presumed that it exerts an effect on improving the thermal degradation property.

The polyester film is excellent in surface flatness and dry heat deterioration resistance, and is useful as a base film for a magnetic recording medium, particularly a base film for vapor deposition video.

[0032]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to the examples without departing from the gist thereof. In the examples, "parts" means parts by weight. Further, the measurement of each characteristic value in the embodiment is performed by the following method.

(1) Film surface flatness The surface of the small side of the film was subjected to gold vapor deposition, and irradiated with differential interference light using an optical microscope, at a magnification of 200 × 3 mm × 3 mm.
Observe the range. Particles that can be recognized as protrusions are counted, and the flatness of the film is evaluated. [Four-step judgment] ◎ The number of projections is 20 / mm ² or less ○ The number of projections is 21 to 40 / mm ² × The number of projections is 41 to 99 / mm ² ×× The number of projections is 100 / mm ² or more

(2) Dry Heat Degradability A film is uniformly spread on a fixed frame, and the film is placed in a preheated hot air dryer and treated for 3 minutes (treatment conditions: temperature = 230 ° C., atmosphere = Air). After the treatment, the film is taken out and the deterioration is visually evaluated and touched to evaluate. [Three-step judgment] フ The film is hardly deteriorated and does not break even if it is pulled strongly by hand. ○ The film retains its shape, but breaks when pulled hard by hand. × The film is broken and easily touched by hand
State .

[0035]

Example 1 Production of polyethylene terephthalate: 100 parts of dimethyl terephthalate and 70 parts of ethylene glycol were mixed with calcium acetate 1 as a transesterification catalyst.
After transesterification according to a conventional method using 0.031 part (1.6 mol) of a water salt and 0.043 part (2.0 mol) of magnesium acetate tetrahydrate, 0.014 part of trimethyl phosphate. (1.0 mol) was added to substantially terminate the transesterification reaction. Further, after addition of 0.003 part (0.08 mol) of titanium tetrabutoxide, polycondensation was carried out as usual under a high temperature and high vacuum to obtain polyethylene terephthalate having an intrinsic viscosity (o-chlorophenol, 35 ° C) of 0.60. I got

Production of biaxially stretched film: After drying the polyethylene terephthalate pellets at 170 ° C. for 3 hours, it is supplied to an extruder hopper and melted at a temperature of 280 to 300.
The melted polymer was extruded through a 1 mm slit die onto a rotating cooling drum having a surface finish of about 0.3 s and a surface temperature of 20 ° C. to obtain a 200 μm unstretched film. The unstretched film thus obtained was
Preheat at 5 ° C, and 15 mm between low and high speed rolls
It is heated by one IR heater having a surface temperature of 900 ° C. from above and stretched 3.6 times, and then supplied to a stenter.
The film was stretched 3.9 times in the transverse direction at 105 ° C. The obtained biaxially stretched film was heat-set at a temperature of 210 ° C. for 5 seconds to obtain a heat-set biaxially stretched film having a thickness of 14 μm.

Table 1 shows the characteristics of this film.

[0038]

Example 2 The amount of calcium acetate monohydrate was 1.0 mol,
The procedure was performed in the same manner as in Example 1 except that the amount of magnesium acetate tetrahydrate was changed to 1.2 mol. Table 1 shows the properties of the obtained biaxially stretched film.

[0039]

Example 3 The amount of calcium acetate monohydrate was 2.2 mol,
The procedure was performed in the same manner as in Example 1 except that the amount of magnesium acetate tetrahydrate was changed to 2.8 mol. Table 1 shows the properties of the obtained biaxially stretched film.

[0040]

Example 4 The amount of calcium acetate monohydrate was 1.9 mol,
Example 1 was repeated except that the amount of magnesium acetate tetrahydrate was changed to 1.9 mol. Table 1 shows the properties of the obtained biaxially stretched film.

[0041]

Example 5 The amount of calcium acetate monohydrate was 0.5 mol,
The procedure was performed in the same manner as in Example 1 except that the amount of magnesium acetate tetrahydrate was changed to 2.9 mol. Table 1 shows the properties of the obtained biaxially stretched film.

[0042]

Example 6 Example 6 was carried out in the same manner as in Example 1, except that the amount of trimethyl phosphate was changed to 2.0 mol. Table 1 shows the properties of the obtained biaxially stretched film.

[0043]

Example 7 The amount of calcium acetate monohydrate was 1.4 mol,
The procedure was performed in the same manner as in Example 1 except that the amount of trimethyl phosphate was changed to 0.5 mol and the amount of titanium tetrabutoxide was changed to 0.15 mol. Table 1 shows the properties of the obtained biaxially stretched film.

[0044]

Example 8 Same as Example 1 except that spherical spherical silica having an average particle size of 0.12 μm was added as a lubricant in an amount of 0.03% by weight relative to the acid component (20 minutes after the addition of trimethyl phosphate). Carried out. Table 1 shows the properties of the obtained biaxially stretched film.

[0045]

Example 9 The procedure of Example 1 was repeated, except that the transesterification method was changed to the direct esterification method (using 86 parts of terephthalic acid). Table 1 shows the properties of the obtained biaxially stretched film.
Shown in

[0046]

Example 10 Dimethyl terephthalate was replaced with dimethyl-
The same operation as in Example 1 was carried out except that 126 parts of 2,6-naphthalate was used. Table 1 shows the properties of the obtained biaxially stretched film.

[0047]

Comparative Example 1 The amount of calcium acetate monohydrate was 0.9 mol,
Except that the amount of magnesium acetate tetrahydrate was changed to 1.0 mol, the same procedure as in Example 1 was carried out, but the transesterification reaction was delayed, so that the transesterification was discontinued and no further evaluation was carried out.

[0048]

Comparative Example 2 The amount of calcium acetate monohydrate was 2.4 mol,
The operation was performed in the same manner as in Example 1 except that the amount of magnesium acetate tetrahydrate was changed to 3.0 mol. Table 1 shows the properties of the obtained biaxially stretched film.

[0049]

Comparative Example 3 The amount of calcium acetate monohydrate was 2.0 mol,
The procedure was performed in the same manner as in Example 1 except that the amount of magnesium acetate tetrahydrate was changed to 1.6 mol. Table 1 shows the properties of the obtained biaxially stretched film.

[0050]

Comparative Example 4 The amount of calcium acetate monohydrate was 0.5 mol,
The procedure was performed in the same manner as in Example 1 except that the amount of magnesium acetate tetrahydrate was changed to 3.1 mol. Table 1 shows the properties of the obtained biaxially stretched film.

[0051]

Comparative Example 5 The amount of calcium acetate monohydrate was 1.2 mol,
The procedure was performed in the same manner as in Example 1, except that the amount of magnesium acetate tetrahydrate was changed to 1.6 mol, the amount of trimethyl phosphate was changed to 2.0 mol, and the amount of titanium tetrabutoxy was changed to 0.15 mol. However, since the reaction was delayed in the polycondensation reaction, the reaction was terminated on the way, and the subsequent evaluation was not performed.

[0052]

Comparative Example 6 The amount of calcium acetate monohydrate was 1.5 mol,
The procedure was performed in the same manner as in Example 1 except that the amount of magnesium acetate tetrahydrate was changed to 2.1 mol and the amount of trimethyl phosphate was changed to 0.5 mol. Table 1 shows the properties of the obtained biaxially stretched film.

[0053]

Comparative Example 7 The amount of titanium tetrabutoxide was set at 0.
It carried out similarly to Example 1 except having changed to 18 mol.
Table 1 shows the properties of the obtained biaxially stretched film.

[0054]

Comparative Example 8 The same operation as in Example 1 was carried out except that titanium tetrabutoxide was changed to 0.8 mol of antimony trioxide. Table 1 shows the properties of the obtained biaxially stretched film.

[0055]

[Table 1]

As is clear from the results in Table 1, when the polyester obtained in the present invention was used as a film,
The surface flatness was extremely good, and the resistance to dry heat deterioration was satisfactory.

[0057]

EFFECT OF THE INVENTION The polyester according to the present invention has very little generation of residual particles due to a catalyst, has good surface flatness as a film, has excellent resistance to dry heat deterioration, and has an extremely high industrial value.

Continuation of the front page (56) References JP-A-4-270727 (JP, A) (58) Field surveyed (Int. Cl. ⁶ , DB name) C08G 63/82-63/87

Claims (2)

(57) [Claims] Upon 1. A by reacting an aromatic dicarboxylic acid and / or an ester-forming derivative thereof and a glycol to produce a polyester, at any stage until the reaction is complete, the magnesium compound, calcium compound, titanium
A method for producing a polyester, comprising adding a phosphorus compound and a phosphorus compound so as to satisfy the following formulas (1) to (4). 2.1 ≦ (Mg + Ca) ≦ 5.1 (1) 1.0 ≦ (Mg / Ca) ≦ 6.0 (2) 1.6 ≦ (Mg + Ca) /P≦7.0 (3) 0 <Ti ≦ 0.15 (4) (In the above formula, Mg is the acid component 10 of the magnesium element.
⁶ g per mole, Ca is the number of moles of calcium element per 10 ⁶ g of the acid component, Ti is the mole number of titanium element per 10 ⁶ g of the above acid component, and P is 10 ⁶ g of the above acid component of the phosphorus element. The number of moles per unit is shown. ) 2. The method according to claim 1, wherein the polyester is polyethylene terephthalate or polyethylene-2,6-naphthalate.