JP3335683B2 - Polyester film and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

This invention relates to a polyester film and
Relates to a method of manufacturing a Yobiso, more particularly to enhance the thermal stability of the polymer to inhibit the formation of insoluble foreign matter in the film,
The present invention relates to a method for producing a polyester film of excellent quality.

[0002]

2. Description of the Related Art Aromatic polyesters represented by polyethylene terephthalate have excellent physical and chemical properties, and are widely used in film applications such as magnetic tapes, electrical insulating materials, capacitors, photographic films, and packaging materials. ing.

[0003] Such aromatic polyesters are usually composed of dialkyl terephthalate and ethylene glycol.
The mixture is heated to 30 to 270 ° C. to carry out a transesterification reaction while distilling off by-produced alcohol, and then the glycol ester of terephthalic acid and / or a low polymer thereof is heated to 250 to 300 ° C. under reduced pressure to obtain a secondary ester. It is produced by causing a polymerization reaction while distilling free glycol produced. The aromatic polyester thus obtained is put into practical use by, for example, extruding it into a film form from a fine slit in a molten state and then stretching it.

[0004] In the production of aromatic polyesters, a catalyst is required for the reaction to proceed smoothly, and various metal compounds have been proposed as such catalysts. In particular, as a transesterification catalyst, a manganese compound such as manganese acetate has excellent transesterification ability and is widely used to form a polyester of relatively good quality. As a polymerization reaction catalyst, an antimony compound such as antimony trioxide is most widely used because it has an excellent polymerization reaction accelerating effect and forms a polyester having a relatively good color tone.

[0005] However, polyesters obtained using a manganese compound-antimony compound catalyst system have the drawback of poor moldability. That is, fish eyes are generated or easily generated during film forming.

Heretofore, these drawbacks have been considered to be caused by insoluble contaminants generated in the polymer. As a countermeasure, a specific amount and ratio of a manganese compound and a cobalt compound are used in combination, and a specific titanium compound is used as a polymerization catalyst. Method using a specific amount of (JP-B-60-42810)
), A method in which a manganese compound and an alkali metal compound are used together in a specific amount and ratio, a specific phosphorus compound is used, and a specific amount of a specific titanium compound is further used as a polymerization reaction catalyst (Japanese Unexamined Patent Publication No. 278927) have been proposed, but they have not yet achieved sufficient effects. In particular, a polyester using a titanium compound has a large decrease in the degree of polymerization at a high temperature of 200 ° C. or more, as compared with a polyester using an antimony compound instead of the titanium compound, and thus the film strength is often inferior.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to enhance the thermal stability of a polymer to suppress the formation of insoluble contaminants in a film and have excellent quality. An object of the present invention is to provide a method for producing a polyester film useful as a base material for tapes, magnetic tapes for computers, floppy disks, radiographic films, telephone cards, membranes, diazo microfilms and the like.

[0008]

According to the present invention, there is provided, according to the present invention, polyethylene terephthalate or polyethylene-2,6-naphthalene polymerized by using a titanium compound as a polymerization reaction catalyst at 7 to 120 ppm in terms of titanium atom. (but polyethylene terephthalate or poly
The block copolymer of ethylene-2,6-naphthalate is
Except) was melt-extruded quenched from the die, optionally further stretching, a film produced by subjecting a heat-polymerization is at any stage up to the melt extruded from when substantially complete, polyethylene terephthalate Alternatively, at least one phosphorus compound is added to polyethylene-2,6-naphthalate at a gram atomic ratio of phosphorus atoms to titanium atoms (P / T
i) is from 0.5 to 4.0 and the amount of phosphorus atoms is 150
It is achieved by a polyester film characterized by being added and contained at a ratio of not more than ppm. Further, according to the present invention, an object of the present invention is to use a titanium compound as a polymerization reaction catalyst in an amount of 7 to 120 ppm in terms of titanium atoms.
Used polymerized polyethylene terephthalate or polyethylene-2,6-naphthalate (however, polyethylene
Terephthalate or polyethylene-2,6-naphtha
Block copolymers of the rate excluded) was melt-extruded quenched from the die, stretched further, when subjected to a heat-producing the film, any up to melt-extrusion from the time the polymerization is substantially complete, optionally At least one kind of phosphorus compound is added to polyethylene terephthalate or polyethylene-2,6-naphthalate, and the phosphorus atom to titanium atom gram atomic ratio (P / Ti) is 0.5 to 4.0; This is achieved by a method for producing a polyester film, characterized in that the amount of atoms is 150 ppm or less. Furthermore, as a preferred embodiment of the present invention, according to the present invention, in the above-described polyester film of the present invention and the method for producing the same, the intrinsic viscosity after treatment at 220 ° C. for 30 minutes in an air atmosphere and the intrinsic viscosity before the treatment Is less than 20%, the titanium atom equivalent of the titanium compound is 7 to 50 ppm, and the amount of phosphorus atoms is 34 ppm or less. That is, polyethylene terephthalate is produced through a transesterification reaction between dimethyl terephthalate and ethylene glycol and then polymerized with a titanium compound (particularly, the catalyst used for the transesterification reaction is manganese acetate or acetic acid. Potassium, and the catalyst used in the transesterification reaction is preferably a titanium compound.) The Chi terephthalate is from via an esterification reaction between terephthalic acid and ethylene glycol, is produced by the polymerization reaction with the titanium compound, polyethylene -
Polyester film comprising at least one of 2,6-naphthalate produced through a transesterification reaction between dimethyl 2,6-naphthalenedicarboxylate and ethylene glycol and then polymerized with a titanium compound. And a method of manufacturing the same.

The polyester constituting the film of the present invention is a linear saturated polyester synthesized from an aromatic dibasic acid or an ester-forming derivative thereof and a diol or an ester-forming derivative thereof, ie, polyethylene terephthalate or polyethylene-2. , 6-naphthalate (excluding polyethylene terephthalate or polyether)
Excluding block copolymers of Tylene-2,6-naphthalate
In Ku), also it includes such blends thereof with minor proportion of other resins.

Such polyethylene terephthalate or
Polyethylene-2,6-naphthalate (hereinafter referred to as polyethylene
Lenterephthalate or polyethylene-2,6-naph
Talate may be referred to as polyester. ) Can be produced by a conventionally known method. For example, polyethylene terephthalate can be produced by an esterification reaction of terephthalic acid and ethylene glycol or a transesterification reaction of dimethyl terephthalate and ethylene glycol, and then polymerizing the reaction product. A known catalyst can be used in the transesterification reaction or esterification reaction, but it is necessary to use a titanium compound, particularly an organic titanium compound, as a polymerization reaction catalyst from the viewpoint of film characteristics.

As the organic titanium compound, there can be mentioned, for example, those described in JP-A-63-278927. To further explain, an alcoholate or an organic acid salt of titanium, a reaction product of a tetraalkyl titanate and an aromatic polycarboxylic acid or an anhydride thereof or the like can be exemplified, and titanium tetrabutoxide as a preferred specific example,
Examples include titanium tetraisopropoxide, titanium oxalate, titanium acetate, titanium benzoate, titanium trimellitate, and a reaction product of tetrabutyl titanate with trimellitic anhydride.

The amount of the titanium compound to be used is such that the titanium atom is 7 to 120 ppm in the polyester, preferably 7.
The amount is 5 to 75 ppm. If the titanium atom in the polyester is less than 7 ppm, the polymerization reaction time becomes longer,
On the other hand, when the content exceeds 120 ppm, the thermal decomposition reaction proceeds simultaneously during the polymerization reaction, so that the degree of polymerization does not increase, which is not preferable. The addition time of the titanium compound may be any time as long as it is before the beginning of the polymerization reaction. For example, the titanium compound may be present from the beginning of the transesterification reaction, or may be added in two or more times for the purpose of controlling the polymerization reaction rate. May be used. Titanium compounds, especially organotitanium compounds, change into various forms within the reaction system and may be present in the final polyester as a different compound than the one added initially.

In the present invention, the above-mentioned polyester is melt-extruded from a die by a conventional method, rapidly cooled, stretched and oriented in at least one axial direction if desired, and heat-set to form a film. Biaxial stretching can be performed by a biaxial stretching method such as a sequential biaxial stretching method or a simultaneous biaxial stretching method. The obtained biaxially oriented polyester film is usually heated at a rate of 10 ° C. in a nitrogen atmosphere using a differential scanning calorimeter.
It has a crystal orientation characteristic in which the heat of fusion determined at / min is 4 cal / g or more. The thickness of the film after stretch orientation is generally 0.5 to 100 μm, preferably 1 to 50 μm.

In the present invention, it is necessary to incorporate a phosphorus atom before melt-extruding the polyester. This method of containing a phosphorus atom can be achieved by adding a phosphorus compound to the polyester. Here, the phosphorus compound is not particularly limited as long as the compound contains phosphorus. For example, phosphoric acid, phosphorous acid, phosphonic acid and derivatives thereof can be mentioned. In particular,
Phosphoric acid, phosphorous acid, trimethyl phosphate, tributyl phosphate, triphenyl phosphate, monomethyl phosphate, dimethyl phosphate, phenylphosphonic acid, phenylphosphonic acid dimethyl ester, phenylphosphonic acid diethyl ester, phosphorus Ammonium acid and the like. Two or more of these phosphorus compounds may be used in combination.

The amount of the phosphorus compound added is such that the gram atomic ratio (P / Ti) of phosphorus atoms to titanium atoms in the polyester is 0.5 to 4.0, preferably 0.5 to 3.0, and It is necessary that the total amount of phosphorus atoms therein satisfies 150 ppm or less, preferably 115 ppm or less. If the gram atomic ratio (P / Ti) is less than 0.5, the effect of improving the heat resistance of the polyester is insufficient.
If it exceeds 0, side effects due to an excessive amount of the phosphorus compound, for example, decomposition effects occur, which is not preferable.

The time of addition of the phosphorus compound is from the stage at which the polymerization reaction of the polyester is substantially completed to the stage at which the polymer is melt-extruded from a die, and can be arbitrarily selected during this period. The addition may be performed at once, or may be performed in two or more divided portions. Examples of the addition method include a method of directly adding a predetermined amount of a phosphorus compound, and a method of adding a so-called master polymer (master batch) containing a high concentration of a phosphorus compound. That is, a method of directly adding a predetermined amount of a phosphorus compound to a molten polyester at the end of a polymerization reaction, or a method of adding a predetermined amount of a phosphorus compound diluted with a medium, and adding and mixing a predetermined amount of a phosphorus compound to a solid polyester. Examples of the method include a method of mixing a predetermined amount of a master polymer, a method of melt-kneading a predetermined amount of a phosphorus compound during melt extrusion of a polyester film, and a method of melt-kneading a predetermined amount of a master polymer.

In the present invention, the polyester can contain, as desired, inert fine particles (lubricants), antistatic agents, light-blocking agents, stabilizers, and the like. Implementation of a well-known coating in the art for improving the surface characteristics of the polyester film such as the moldability may be used as long as the effects of the present invention are not impaired.

The polyester film of the present invention has a very flat base for a magnetic tape, particularly a base for a magnetic tape for forming a metal thin-film magnetic layer, and a capacitor, since the polyester film of the present invention has a particularly small amount of insoluble foreign matter and excellent heat resistance. Useful for applications and circuit forming applications.

Various properties herein are measured by the following methods.

(1) Intrinsic viscosity [η] It is determined from the value measured at 35 ° C. during melting of orthochlorophenol.

(2) Ti, P content in polyester A predetermined amount of polymer or film is decomposed with a mixed acid of hydrochloric acid and nitric acid, and the volume is adjusted to a constant volume by adding an yttrium solution.
According to the internal standard method of yttrium based on G1258, Ti,
The amount of P is measured.

(3) Heat resistance When the film is subjected to a tension treatment at 220 ° C. for 30 minutes in an air atmosphere, the reduction rate of the intrinsic viscosity before and after the treatment is evaluated by the following equation.

[0023]

(Equation 1)

X: The reduction rate of the intrinsic viscosity is 50% or more Δ: The reduction rate of the intrinsic viscosity is 20 to 50% ○: The reduction rate of the intrinsic viscosity is less than 20%

[0025]

The present invention will be further described below with reference to examples. In addition, the part in an example means a weight part.

[0026]

Example 1 0.0111 parts of titanium tetrabutoxide was added to a mixture of 100 parts of dimethyl 2,6-naphthalenedicarboxylate and 60 parts of ethylene glycol, and the mixture was heated at 150 ° C.
The transesterification reaction was carried out while gradually raising the temperature from 240 ° C to 240 ° C. When the transesterification rate reaches 98%,
The reaction product was transferred to a polymerization reactor, and a polymerization reaction was performed under a high-temperature vacuum (final internal temperature: 290 ° C.) to obtain polyethylene-2,6-naphthalate having an intrinsic viscosity of 0.57.

To 100 parts of this polyethylene-2,6-naphthalate chip, 0.0104 parts of phenylphosphonic acid was added, mixed with a V-type blender, and dried at 170 ° C. for 5 hours. Thereafter, it is melt-extruded from a die according to a conventional method, and quenched to prepare an unstretched film having a thickness of 180 μm.
The film was successively biaxially stretched by 4.0 times at 155 ° C. and 5.0 times at 155 ° C. in the transverse direction, and further heat-set at 220 ° C. for 10 seconds to prepare a biaxially oriented film having a thickness of 9.0 μm.

Table 1 shows the characteristics of this film.

[0029]

Example 2 100 parts of dimethyl terephthalate, 70 parts of ethylene glycol, manganese acetate tetrahydrate 0.019
Parts and potassium acetate 0.0025 parts were charged to the reactor,
The transesterification was performed while gradually increasing the internal temperature from 145 ° C. When the transesterification rate reaches 95%, 0.0108 parts of trimethyl phosphate is added, and an ethylene glycol slurry of silicon dioxide having an average particle diameter of 0.25 μm (silicon dioxide 10 wt% / ethylene glycol slurry) 0.5 Parts were added. After sufficiently stirring, 0.00876 parts of titanium tetrabutoxide was added. Next, the reaction product was transferred to a polymerization reactor, and a polymerization reaction was carried out under a high-temperature vacuum (final internal temperature: 290 ° C.) to obtain polyethylene terephthalate having an intrinsic viscosity of 0.62.
Next, this molten polyethylene terephthalate 10
After adding 0.00438 parts of trimethyl phosphate to 0 parts and sufficiently stirring, polyethylene terephthalate having an intrinsic viscosity of 0.60 was obtained.

This polyethylene terephthalate is dried, melt-extruded and quenched according to a conventional method to prepare an unstretched film having a thickness of 150 μm. Then, the unstretched film is stretched 3.6 times at 90 ° C. in the longitudinal direction and transversely. 3.7-fold sequential biaxial stretching was performed at 105 ° C., and heat setting was further performed at 230 ° C. for 10 seconds to prepare a biaxially oriented film having a thickness of 10.5 μm. At this time, a coating liquid having the following composition was applied to one surface of the uniaxially stretched film by a roll coating method before the transverse stretching.

Composition of coating liquid applied to film surface: 3.0 wt% solution of acrylic resin (Julima AT-510, manufactured by Nippon Pure Chemical Co., Ltd.) 80.0 parts Polyoxyethylene nonyl phenyl ether (Nippon Oil & Fats Co., Ltd.) 3.0 wt% solution of NS240) 20.0 parts

[0032]

Example 3 100 parts of dimethyl terephthalate, 70 parts of ethylene glycol and 0.0293 parts of titanium tetraisopropoxide were charged into a reactor, and transesterification was carried out while gradually increasing the internal temperature from 145 ° C. When the transesterification rate reaches 97%, orthophosphoric acid 0.002
53 parts were added and sufficiently stirred. Next, the reaction product was transferred to a polymerization reactor, and a polymerization reaction was carried out under a high-temperature vacuum (final internal temperature: 290 ° C.) to obtain polyethylene terephthalate (A) having an intrinsic viscosity of 0.62.

On the other hand, 1.008 parts of orthophosphoric acid was added to the molten polyethylene terephthalate (A), and after sufficient stirring, polyethylene terephthalate (B) having an intrinsic viscosity of 0.60 was obtained.

After drying these polyethylene terephthalate chips (A) and (B) by a conventional method, 99.2 parts of polyethylene terephthalate (A) and 0.8 parts of polyethylene terephthalate (B) are sufficiently mixed, and the mixture is mixed according to a conventional method. 2. Melt extruded, quenched to produce an unstretched film having a thickness of 130 μm, and then unstretched film at 90 ° C. in the machine direction.
The film was sequentially biaxially stretched 6 times and 4.0 times in the transverse direction at 110 ° C., and further heat-set at 220 ° C. for 7 seconds to obtain a thickness of 9.0 μm.
m was prepared.

Table 1 shows the characteristics of this film.

[0036]

Example 4 A mixture of 100 parts of terephthalic acid bis-β-hydroxyethyl ester, 65 parts of terephthalic acid and 29 parts of ethylene glycol was subjected to an esterification reaction at a temperature of 210 to 230 ° C. The reaction was terminated when the amount of distilled water produced by the reaction reached 13 parts, and the reaction product 1
After adding 0.0067 parts of titanium acetate per 00 parts and sufficiently stirring, the reaction product is transferred to a polymerization reactor, and a polymerization reaction is performed under a high-temperature vacuum (final internal temperature: 285 ° C.) to obtain an intrinsic viscosity of 0.1. 60 polyethylene terephthalates were obtained.

When the polyethylene terephthalate is melt-extruded according to a conventional method, 0.00769 parts of phosphorous acid is added per 100 parts of polyethylene terephthalate, quenched to prepare an unstretched film having a thickness of 330 μm, and then the unstretched film is formed. Was sequentially biaxially stretched 3.6 times at 90 ° C. in the machine direction and 3.7 times at 105 ° C. in the transverse direction.
The film was heat-set at 0 ° C. for 10 seconds to prepare a biaxially oriented film having a thickness of 25.0 μm.

Table 1 shows the characteristics of this film.

[0039]

Comparative Example 1 In Example 4, 0.00769 phosphoric acid was used.
A biaxially oriented film was prepared in exactly the same manner as in Example 4 except that no part was added.

Table 1 shows the characteristics of this film.

[0041]

Comparative Example 2 Phosphorous acid in Example 4 0.00769
Examples except for changing the parts to 0.0459 parts orthophosphate 4
A biaxially oriented film was prepared in exactly the same manner as described above.

Table 1 shows the film characteristics.

[0043]

Comparative Example 3 Titanium acetate 0.0067 in Example 4
Parts were changed to 0.134 parts to obtain polyethylene terephthalate having an intrinsic viscosity of 0.35.

When this polyethylene terephthalate is melt-extruded in a conventional manner, a biaxially oriented film having a thickness of 25.0 μm is obtained in the same manner as in Example 4 by adding 0.0427 parts of phosphorous acid per 100 parts of polyethylene terephthalate. Was.

The characteristics of this film are shown in Table 1. The film had a low intrinsic viscosity and was insufficient in both the strength and elongation of the film to be practically usable.

[0046]

[Table 1]

[0047]

According to the present invention, the thermal stability of a polymer is increased to suppress the generation of insoluble foreign matter in a film, and the film has excellent quality. For example, a magnetic recording medium, an electrical insulating material, a capacitor, a membrane switch , it is possible to provide a method for producing a useful polyester film and its photographic film, as a base, such as diazo microfilm.

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁷ Identification code FI B29L 7:00 B29L 7:00 (56) References JP-A-51-41095 (JP, A) JP-A-52-33996 (JP) JP-A-4-189821 (JP, A) JP-A-4-214757 (JP, A) JP-A-5-117379 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB Name) B29C 47/00-47/96 C08K 3/00-13/08 C08L 1/00-101/16 C08G 63/00-64/42

Claims (9)

(57) [Claims] 1. A polyethylene terephthalate or polyethylene-2,6-naphthalate polymerized by using a titanium compound as a polymerization catalyst by using a titanium compound in an amount of 7 to 120 ppm in terms of titanium atom (polyethylene terephthalate or polyethylene terephthalate).
Block copolymerization of polyethylene-2,6-naphthalate
Body excluding) was melt-extruded quenched from the die, further stretching, a film produced by subjecting a heat-polymerization is at any stage up to melt-extrusion from the time of substantial completion desired, At least one phosphorus compound is added to polyethylene terephthalate or polyethylene-2,6-naphthalate by the gram atomic ratio of phosphorus atoms to titanium atoms (P /
Ti) is 0.5 to 4.0 and the amount of phosphorus atoms is 15
A polyester film, which is added and contained at a ratio of 0 ppm or less. 2. The difference between the intrinsic viscosity after treatment at 220 ° C. for 30 minutes in an air atmosphere and the intrinsic viscosity before the treatment divided by the intrinsic viscosity before the treatment is less than 20%. The polyester film according to claim 1. 3. A polyethylene terephthalate or polyethylene-2,6-naphthalate polymerized by using a titanium compound as a polymerization reaction catalyst in an amount of 7 to 120 ppm in terms of titanium atom (where polyethylene terephthalate or polyethylene terephthalate is used).
Block copolymerization of polyethylene-2,6-naphthalate
Body excluding) was melt-extruded quenched from the die, stretched further, when subjected to a heat-producing the film, polymerization at any stage up to melt-extrusion from the time of substantial completion desired, polyethylene At least one phosphorus compound is added to terephthalate or polyethylene-2,6-naphthalate, and the gram atomic ratio (P /
Ti) is 0.5 to 4.0 and the amount of phosphorus atoms is 15
A method for producing a polyester film, wherein the polyester film is added and contained at a ratio of 0 ppm or less. 4. The titanium compound has a titanium atom equivalent of 7 to 7.
The method for producing a polyester film according to claim 3, wherein the amount is 50 ppm and the amount of phosphorus atoms is 34 ppm or less. 5. The method for producing a polyester film according to claim 3, wherein the polyethylene terephthalate is produced through a transesterification reaction between dimethyl terephthalate and ethylene glycol and then a polymerization reaction with a titanium compound. 6. The method for producing a polyester film according to claim 5, wherein the catalyst used in the transesterification reaction is manganese acetate or potassium acetate. 7. The method for producing a polyester film according to claim 5, wherein the catalyst used for the transesterification reaction is a titanium compound. 8. The method for producing a polyester film according to claim 3, wherein the polyethylene terephthalate is produced by an esterification reaction between terephthalic acid and ethylene glycol, followed by a polymerization reaction with a titanium compound. 9. The method according to claim 3, wherein the polyethylene-2,6-naphthalate is produced by a transesterification reaction between dimethyl 2,6-naphthalenedicarboxylate and ethylene glycol, followed by a polymerization reaction with a titanium compound. Method for producing polyester film.