JP3287128B2 - Polyester production method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

This invention relates to a method for producing polyester. More specifically, the present invention relates to a method for producing a polyester in which oligomers that bleed out when formed into a film or the like are reduced.

[0002]

2. Description of the Related Art Polyester films are widely used in many applications such as magnetic tapes, electrical insulation, photographic applications, metallizing applications, and packaging applications because of their excellent properties. In particular, a polyethylene terephthalate film and a polyethylene-2,6-naphthalate film are excellent in flatness, mechanical strength, chemical properties, dimensional stability and the like, and are suitably used as a base film of a magnetic recording medium.

On the other hand, with the development of a magnetic recording medium in recent years, the characteristics required for a base film have become increasingly severe.

For example, in order to increase the density of a video tape, the surface of a base film is required to be more flat. However, when the oligomer bleeds out, many harmful effects such as scratches on the film surface are caused, and a coating loss occurs in a step of coating the magnetic layer, which causes a dropout of magnetic recording. Further, when a magnetic tape is used, dropout (dropout) of magnetic recording occurs during recording and reproduction. As a method for reducing the oligomer which causes the bleed-out, Japanese Patent Application Laid-Open No. 1-306421 proposes to reduce the oligomer by solid-phase polymerization. However, this method has a problem that the obtained polymer has a remarkably high degree of polymerization, requires a higher temperature than usual for melting to form a film or the like, and has a high melt viscosity and poor moldability.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned disadvantages of the prior art and to obtain a polyester having a small amount of oligomers.

[0006]

An object of the present invention is to obtain a diol and / or an ester-forming derivative thereof and an aromatic dicarboxylic acid and / or a dicarboxylic acid mainly containing an ester-forming derivative thereof. Polycondensation of a glycol ester of a dicarboxylic acid and / or a low polymer thereof to an oligomer extraction amount of 0.7% or less.
When the polyester is produced, it is achieved by polycondensation under stirring at a shear rate of 10 sec ^-1 or more.

The diol used in the present invention includes ethylene glycol, 1,2-propanediol, 1,3
-Propanediol, neopentyl glycol, 1,3
-Butanediol, 1,4-butanediol, 1,5-
Aliphatic diols such as pentanediol, 1,6-hexanediol, diethylene glycol, triethylene glycol, polyalkylene glycol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, , 4
Alicyclic diols such as -cyclohexanediol, hydroquine, 2,6-naphthalenediol, 1,5-naphthalenediol, 1,4-naphthalenediol, 4,4 '
Aromatic diols such as -biphenol and 2,2'-bis (4'-β-hydroxyethoxyphenyl) propane; and the like, preferably aliphatic diols and alicyclic diols, more preferably aliphatic diols. And more preferably ethylene glycol, 1,3-propanediol, 1,4-butanediol and the like. These diol components may be used alone or in combination of two or more.

The aromatic dicarboxylic acids of the present invention are terephthalic acid, isophthalic acid, 1,3-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 1,6-naphthalenedicarboxylic acid Acid, 1,7-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid,
2,7-naphthalenedicarboxylic acid, 3,3′-biphenyldicarboxylic acid, 3,4′-biphenyldicarboxylic acid,
4,4′-biphenyldicarboxylic acid and the like, terephthalic acid, 1,4-naphthalenedicarboxylic acid,
1,5-Naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, and 4,4′-biphenyldicarboxylic acid are preferred, and 2,6-naphthalenedicarboxylic acid, 4,4′-
Biphenyl dicarboxylic acid is more preferred. These acid components may be used alone or in combination of two or more,
Further, an aromatic oxycarboxylic acid such as p-hydroxybenzoic acid may be partially copolymerized.

These polyesters include, as copolymerization components, dicarboxylic acids such as adipic acid, sebacic acid, phthalic acid, diphenoxyethane dicarboxylic acid, dichlorophenoxyethane dicarboxylic acid, diphenyl ether dicarboxylic acid, diphenyl sulfone dicarboxylic acid, and diphenyl ketone dicarboxylic acid. Acids and their ester-forming derivatives, trimellitic acid, pyromellitic acid, glycerol,
Pentaerythritol, 2,4-dioxybenzoic acid,
The polymer is substantially linear with other compounds such as trifunctional or higher polyfunctional compounds such as 2,4-dioxybenzoic acid and 4-oxyisophthalic acid, and monofunctional compounds such as benzoic acid, lauryl alcohol and phenyl isocyanate. It may be copolymerized within the range of the shape.

The polyester used in the present invention may contain various additives such as an ultraviolet absorber, an antistatic agent, a stabilizer and a colorant.

Further, various particles are blended with the polyester used in the present invention for the purpose of improving the processability in the molding process and the handling properties, workability and commercial value of the resulting molded articles such as fibers and films. It may be. Specifically, natural products can be pulverized and classified, or various particles produced by a synthetic method can be used. Specifically, inorganic particles such as silicon dioxide, titanium dioxide, aluminum oxide, zirconium oxide, calcium carbonate, cerium dioxide, molybdenum oxide, tungsten oxide, calcium phosphate, barium sulfate, iron oxide, kaolin, and carbon, alkali metals and alkaline earths Particles precipitated in a polyester polymerization reaction system containing at least one kind of metal and phosphorus as a constituent component, that is, internal particles, further, silicone resin particles, epoxy resin particles, polyimide particles, cross-linked polystyrene particles, alkyd particles and the like Examples include various crosslinked polymer particles such as vinyl-based particles.

In producing the polyester of the present invention,
A diol and / or an ester-forming derivative thereof;
A known method can be employed for reacting a dicarboxylic acid mainly composed of an aromatic dicarboxylic acid and / or an ester-forming derivative thereof to obtain a glycol ester of a dicarboxylic acid and / or a low polymer thereof. When the obtained glycol ester of dicarboxylic acid and / or its low polymer is further polycondensed, a known method and apparatus can be employed, but at this time, it is necessary to carry out the polymerization under stirring at a shear rate of 10 sec ^-1 or more. is there. If it is less than this, it is not possible to obtain a low oligomer polyester which is an effect of the present invention. For that purpose, it is important to control the stirring speed and the gap between the stirring blade and the inner wall.

The amount of oligomers extracted from the polyester obtained by the production method of the present invention is preferably 1.0% or less. When the characteristic value is within the above range, for example, the surface smoothness when formed into a film is excellent, which is preferable. More preferably, it is 0.7% or less, still more preferably 0.5% or less.

In the case of producing a film made of polyester obtained by the production method of the present invention, the film can be applied to both a single layer and a laminated film. Particularly preferred is a laminated film composed of two or more possible layers. When the layer composed of polyester obtained by the production method of the present invention is applied to at least one layer, particularly three or more laminated films, at least one of the laminated films is preferably used. It is preferably the outermost layer. When a layer containing various particles is provided in order to improve the slipperiness of the film, it is preferable that the layer is at least one of the outermost layers. The relationship between the thickness t and the particle diameter d of the contained particles is preferably 0.2d ≦ t ≦ 10d, more preferably 0.5d ≦ t ≦ 5d, and still more preferably 0.5d ≦ t ≦. 3d.

Next, a method for producing a laminated film having a layer comprising the polyester of the present invention will be described. After optionally drying the pellets containing the polyester obtained by the production method of the present invention and the pellets containing a predetermined amount of particles as needed, fed to a known melt laminating extruder,
The sheet is extruded from a slit die into a sheet and cooled and solidified on a casting roll to form an unstretched film.
That is, the polyester in a molten state is laminated using two or three extruders, two or three layers of a manifold or a merging block. In this case, a method of installing a static mixer and a gear pump in the flow path of the polymer containing particles is effective for further improving the effect of the present invention. Next, this unstretched film is biaxially stretched and biaxially oriented. As the stretching method, a sequential biaxial stretching method or a simultaneous biaxial stretching method can be used. However, using a sequential biaxial stretching method in which stretching in the longitudinal direction and then in the width direction is performed first, stretching in the longitudinal direction is divided into three or more stages, the longitudinal stretching temperature is 500 to 170 ° C., and the total longitudinal stretching ratio is 3.0. ~ 8.0
And the longitudinal stretching speed is preferably in the range of 5,000 to 50,000% / min. As the stretching method in the width direction, a method using a stenter is preferable. The stretching temperature is 50 to 170 ° C., the stretching ratio in the width direction is 3.0 to 8.0 times, and the stretching speed in the width direction is 100.
The range of 0 to 20000% / min is preferred. Further, it is also preferable to stretch in the longitudinal direction or subsequently in the transverse direction.
Next, this stretched film is heat-treated. In this case, the heat treatment temperature is preferably 100 to 250 ° C., and the time is preferably in the range of 0.5 to 60 seconds.

The coarse protrusions number of the laminate surface using a polyester obtained by the process of the present invention in the film obtained as above is preferably from 100/100 cm ² or less, and more is 70/100 cm ² or less preferable. More preferably, it is 50 pieces / 100 cm ² or less.

[0017]

The present invention will be described in detail below with reference to examples. In addition, each characteristic value of the obtained polyesterm was calculated | required according to the following method.

(1) Amount of oligomer extracted The polymer was pulverized from 20 mesh to 35 mesh, and the polymer was extracted with chloroform using a Soxhlet extractor.
The amount of chloroform-soluble components extracted over time was determined as a ratio (% by weight) to the polymer subjected to extraction.

(2) Number of Coarse Protrusions on the Film Surface Two measurement surfaces (100 cm ² ) of the film are superimposed and brought into close contact with each other by electrostatic force (applied voltage: 5.4 kV).
The height of the coarse projections was determined from Newton's rings generated by interference of light at the coarse projections between the two films, and one or more rings were counted. 10 because two sheets are piled
This means that 200 cm ^{2 is} measured with a 0 cm ² sample film. The light source used was a halogen lamp with a 564 nm band-pass filter.

(3) Slipperiness of the film The film was slit to a width of 1/2 inch, and a tape running tester TBT-300 type [manufactured by Yokohama System Laboratory Co., Ltd.]
Was used, and the vehicle was run in an atmosphere of 20% RH and 60% RH. The initial coefficient of friction μk was determined by the following equation. The guide diameter is 6 mmφ, the guide material is SUS27 (surface roughness 0.2S), the winding angle is 180 ° C., and the running speed is 3.3 cm / sec. μk = 0.733 × log (T ₁ / T ₂ ) T ₁ : Outlet tension T ₂ : Inlet tension

Example 1 A transesterification reactor equipped with a stirrer, a rectification column and a condenser was charged with 65.8 dimethyl naphthalene-2,6-dicarboxylate.
After supplying 33.5 parts of ethylene glycol and 0.08 part of manganese acetate tetrahydrate, the temperature was gradually raised to 170 ° C. to 240 ° C., and simultaneously produced methanol was continuously distilled out of the reaction system. A transesterification reaction was performed. To the thus obtained reaction product, 0.04 part of trimethyl phosphate was added and reacted for 15 minutes, then 0.03 part of antimony trioxide was added, and the reaction was further performed for 5 minutes.

Subsequently, while continuously distilling ethylene glycol, the temperature was raised to 290 ° C. and at the same time 0.2 mmH
g, and the polycondensation reaction was carried out.
A shear rate of 5 sec ^-1 was created between the stirring blade and the inner wall. The intrinsic viscosity of the obtained polyester is 0.65
The oligomer extraction amount was 0.3%. This polymer is designated as A.

On the other hand, polyethylene-2,6-naphthalate containing 0.5 μm silica particles (hereinafter referred to as polymer B) was obtained by a known polymerization method. After drying the two polymers under reduced pressure, the polymers A and B were supplied to the extruder 1 and the extruder 2, respectively, melted, and subjected to high-precision filtration. This was wound around a casting drum using an electrostatic application casting method, and cooled and solidified to prepare an unstretched film. The unstretched film was stretched 5.0 times in the longitudinal direction and 6.0 times in the width direction and heat-treated to obtain a biaxially oriented laminated film having a total thickness of 15 µm. When the characteristics of this film were examined, the number of coarse projections on the surface of the laminated portion using the polyester obtained by the production method of the present invention was 24.
Pieces / cm ² , showing good surface properties, and the lamination surface containing silica particles having a good running property of 0.32.

Example 2 In a transesterification reactor equipped with a stirrer, a rectification column and a condenser, 26.3 parts of dimethyl terephthalate, 39.5 parts of dimethyl 4,4'-biphenyldicarboxylate and 33.5 parts of ethylene glycol were added. And 0.08 part of manganese acetate tetrahydrate were supplied, then the temperature was gradually raised to 170 ° C. to 240 ° C., and simultaneously produced methanol was subjected to transesterification while continuously distilled out of the reaction system. To the reaction product thus obtained, 0.04 part of trimethyl phosphate was added and reacted for 15 minutes, and then 0.03 part of antimony trioxide was added.
The reaction was further performed for 5 minutes.

Subsequently, the temperature was raised to 290 ° C. while continuously distilling ethylene glycol, and at the same time, 0.2 mmH
g to perform polycondensation reaction.
A shear rate of 5 sec ^-1 was created between the stirring blade and the inner wall. The intrinsic viscosity of the obtained polyester is 0.71
The oligomer extraction amount was 0.4%. This polymer is designated as C.

On the other hand, a polymer D containing 0.5 μm silica particles in a polymer having the same composition as the polymer C was obtained by a known polymerization method. After drying the two polymers under reduced pressure,
Polymers C and D were supplied to extruder 1 and extruder 2, respectively, melted, and subjected to high-precision filtration. Then, two layers were laminated at a rectangular junction. This was wound around a casting drum using an electrostatic application casting method, and cooled and solidified to prepare an unstretched film. The unstretched film was stretched 5.0 times in the longitudinal direction and 6.0 times in the width direction and heat-treated to obtain a biaxially oriented laminated film having a total thickness of 17 µm. When the characteristics of this film were examined, the number of coarse protrusions on the surface of the laminated portion using the polyester obtained by the production method of the present invention was as small as 17 / cm ² , showing good surface characteristics, and containing silica particles. Μk of the lamination surface was 0.25, indicating a good running property.

Comparative Example 1 A polyester was obtained in the same manner as in Example 1, except that the shear rate generated between the stirring blade and the inner wall was set to 7 sec ^-1 . The oligomer extraction amount of this polymer was 1.3%. Further, a film was obtained in the same manner as in Example 1. When the characteristics of this film were examined, the number of coarse protrusions on the surface of the laminated portion using the polyester obtained under the conditions deviating from the production method of the present invention was as large as 124 / cm ² and contained silica particles. The μk of the laminated surface was 0.37, which was not a good running property.

[0028]

The polyester obtained by the method of the present invention has few oligomers, has excellent surface properties when formed into a film or the like, and can be suitably used for magnetic recording media.

Claims (4)

(57) [Claims] A glycol ester of a dicarboxylic acid obtained by reacting a diol and / or an ester-forming derivative thereof with a dicarboxylic acid mainly composed of an aromatic dicarboxylic acid and / or an ester-forming derivative thereof, and / or a glycol ester thereof. When producing a polyester by polycondensing a low polymer , the oligomer extraction amount is characterized by polycondensation under stirring at a shear rate of 10 sec ^-1 or more.
A method for producing a polyester of 0.7% or less . 2. The method according to claim 1, wherein the aromatic dicarboxylic acid is 2,6-naphthalenedicarboxylic acid. 3. The method according to claim 1, wherein the aromatic dicarboxylic acid is a mixture of 4,4′-biphenyldicarboxylic acid and terephthalic acid. 4. The method according to claim 1, wherein the diol is ethylene glycol.