JPH0657020A - Copolyester film - Google Patents

Abstract

(57) [Summary] [Structure] A copolymerized polyester composed of units I and II represented by the following formula: (In the formula, Ar ₁ , Ar ₂ , Ar ₃ and Ar ₄ independently represent a divalent aromatic residue, and R ₁ and R ₂ are independently linear or branched having 1 to 12 carbon atoms. Represents a cyclic or cyclic divalent aliphatic, and x and y satisfy the following formulas (1) and (2): x + y = 1 (1) 0.02 ≦ x ≦ 0.70 (2)
) 0.01 to 5.0 wt% of inorganic fine particles having a specific surface area of 1 m ² / g or more based on the copolyester
It is a copolymerized polyester film containing, and the plane orientation index of the copolymerized polyester film is 0.1.
A film that is 5 or more. [Effect] A film that is excellent in mechanical properties under heat, heat resistance, and abrasion resistance. Even if it is thin, it is excellent in handleability during handling.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copolyester film having excellent mechanical properties, heat resistance and abrasion resistance.

[0002]

2. Description of the Related Art In recent years, miniaturization in the field of electric and electronic equipment,
With the progress of weight reduction, not only downsizing of materials to be used but also simplification, shortening of process, speeding up, heat resistance, high strength, and abrasion resistance are required. Aromatic polyesters typified by polyethylene terephthalate have been used in these fields, but they have limited mechanical properties and heat resistance, and in the case of direct contact with metal, wear resistance is low. Without being scraped or scratched,
It has become difficult to satisfy the required characteristics. Therefore, for higher heat resistance and higher rigidity, copolymerization of liquid crystal polyester and liquid crystal components (for example, "High-performance aromatic polymer materials" edited by The Polymer Society of Japan (Maruzen)) is also used to improve wear resistance. A particle addition system (for example, Japanese Patent Laid-Open No. 61-60722) is under study.

[0003]

However, although the liquid crystal polymer has relatively high heat resistance and high rigidity among the molten polymers, it has a problem that it is strongly oriented in the flow direction and the strength in the direction perpendicular thereto is lowered. However, the moldability into a film that needs to be biaxially stretched in the machine direction and the width direction was poor. On the other hand, there was a problem that even if an attempt was made to copolymerize a rigid component that contributes to the expression of liquid crystallinity with an aromatic polyester to such an extent that the liquid crystallinity is not expressed, the degree of polymerization does not increase and a polymer having sufficient strength cannot be obtained. . Furthermore, although the wear resistance has been improved by the effect of adding fine particles, it is not yet sufficient.

An object of the present invention is to provide a copolymerized polyester film which has improved the above-mentioned problems, is excellent in mechanical properties, heat resistance and moldability and has good abrasion resistance.

[0005]

The present invention provides units I and II represented by the following formula.

[Chemical 2] (In the formula, Ar ₁ , Ar ₂ , Ar ₃ and Ar ₄ independently represent a divalent aromatic residue, and R ₁ and R ₂ are independently linear or branched having 1 to 12 carbon atoms. Represents a cyclic or cyclic divalent aliphatic, and x and y satisfy the following formulas (1) and (2): x + y = 1 (1) 0.02 ≦ x ≦ 0.70 (2)
And a copolymerized polyester film containing 0.01 to 5.0% by weight of the inorganic fine particles having a specific surface area of 1 m ² / g or more with respect to the copolymerized polyester. The present invention relates to a copolyester film having a plane orientation index of 0.15 or more. Ar ₁ , Ar ₂ , Ar ₃ and Ar ₄ of the above units I and II constituting the copolyester of the present invention each independently represent a divalent aromatic residue, preferably having 6 carbon atoms.
~ 24 aromatic rings. This aromatic ring is not only one but two
One or more hydrogen atoms may be formed on the aromatic ring, and hydrogen on the aromatic ring may be substituted with a halogen, an alkyl group having 1 to 3 carbon atoms, a phenyl group, a cyano group, a nitro group, or the like. When there is one aromatic ring, para and meta structures are preferable, and when there are two or more aromatic rings, divalent aromatic residues corresponding to these are preferable, and for example, the following structures are more preferable.

[0006]

[Chemical 3] (In the formula, the aromatic ring may be substituted with a halogen, an alkyl group having 1 to 3 carbon atoms, a phenyl group, a cyano group, a nitro group or the like), and more preferably a para type.

[Chemical 4] And so on.

On the other hand, R ₁ and R ₂ independently have 1 to 1 carbon atoms.
It is a linear, branched, or cyclic divalent aliphatic residue having 2 carbon atoms, preferably a linear or branched alkylene group having 2 to 8 carbon atoms, or cycloalkylene having 4 to 10 carbon atoms. Group, a cycloalkylenedialkylene group having 6 to 12 carbon atoms, and more preferably

[Chemical 5] And the like, in _{particular, - (CH 2) 2 -} , - (CH 2) 4 - are preferred.

When the proportion of the above unit I constituting the copolyester of the present invention is x, the proportion of II is y, and x + y = 1, x is in the range of 0.02≤x≤0.70. It is necessary to be. When x <0.02, the effect of the present invention is not remarkable, and the mechanical properties and abrasion resistance are not sufficiently improved, and when x> 0.70, liquid crystal properties start to develop and strongly oriented in one direction to a film or the like. May have poor moldability. Preferably, 0.04 ≦ x ≦ 0.60, and more preferably 0.05 ≦ x ≦ 0.50.

Next, a method for producing the copolyester of the present invention will be described.

First, dicarboxylic acid (III), which is one of the polyester monomers of unit I,

[Chemical 6] (Wherein Ar ₁ , Ar ₂ and Ar ₃ are the same as defined above) or an ester derivative thereof is

[Chemical 7] (Wherein Ar ₁ and Ar ₃ are the same as defined above), for example, methyl of hydroxycarboxylic acid such as p-hydroxybenzoic acid, m-hydroxybenzoic acid and 2-hydroxy-6-naphthoic acid. One or more of ester or ethyl ester derivatives,

[Chemical 8] (Wherein Ar ₂ is the same as defined above), for example, terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 4 , 4'-biphenylenedicarboxylic acid, 3,4'-biphenylenedicarboxylic acid, 3,3'-biphenylenedicarboxylic acid, or one or more of these aromatic ring hydrogens substituted with halogen, alkyl group, etc. It can be obtained by carrying out a deacetic acid reaction using acetic acid. It can also be obtained by reacting the dichloride of the above-mentioned dicarboxylic acid with the above-mentioned hydroxycarboxylic acid or its ester derivative in a solvent in the presence of a dehydrochlorination agent such as triethylamine.

Dicarboxylic acid monomer (IV), which is one of the monomers forming unit II,

[Chemical 9] (Wherein Ar ₄ is as defined above), terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid,
1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 4,4′-biphenylenedicarboxylic acid,
Preference is given to 3,4′-biphenylenedicarboxylic acid, 3,3′-biphenylenedicarboxylic acid, those obtained by substituting the hydrogen of the aromatic ring with halogen, an alkyl group and the like, and alkyl esters thereof.

These dicarboxylic acid monomers (III), (I
V) and diols such as ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-
By polymerizing one or more alkylene glycols such as pentanediol, 1,6-hexanediol and cyclohexanedimethanol by a known method, for example, a solution polycondensation method, a melt polycondensation method or a solid phase polymerization method The copolyester of the invention can be obtained. The total diol and the total dicarboxylic acid monomer (III + IV) are preferably equimolar, but in practice, the number of moles of the diol may be 90 to 110 mol% with respect to the total number of dicarboxylic acid monomers, More preferably, it is 95 to 105 mol%. Further, the dicarboxylic acid monomer III needs to be 2 to 70 mol% with respect to the total dicarboxylic acid monomer.

As a particularly preferred method, a predetermined proportion of dicarboxylic acid which is a source of the above units I and II and /
Or an alkyl ester of a dicarboxylic acid and an alkylene glycol, preferably in an inert atmosphere in the presence of a suitable catalyst such as lithium acetate, calcium acetate, magnesium acetate, manganese acetate, cobalt acetate, tetraalkyl titanate, etc. An esterification reaction or transesterification reaction is carried out at 270 ° C. while removing water or alcohol produced to obtain an oligomer,
Further subsequently, in the presence of a suitable polymerization catalyst such as antimony compound, germanium compound, titanium compound, silicon compound, more specifically antimony trioxide, germanium dioxide, tetraalkyl titanate,
A method of polymerizing at 200 to 320 ° C. under reduced pressure can be mentioned.
Further, the dicarboxylic acid and / or the alkyl ester of the dicarboxylic acid which is the source of the units I and II are separately esterified or transesterified to synthesize an oligomer, which is then mixed at a predetermined ratio before polymerization. You may take the method of doing.

The copolyester thus obtained preferably has an intrinsic viscosity (o-chlorophenol, measured at 25 ° C.) of 0.4 dl / g or more. If it is less than this, the mechanical strength may not be sufficient and molding into a film or the like may be difficult. Solid phase polymerization or the like may be performed to adjust the intrinsic viscosity to this range. More preferably, the intrinsic viscosity is 0.5 to 5.0 dl / g.

The particles contained in the copolyester composition used in the present invention must be inorganic fine particles having a specific surface area of 1 m ² / g or more as measured by the BET adsorption method. If it is less than 1 m ² / g, the background reinforcing effect for improving the wear resistance of the present invention cannot be sufficiently exhibited. Preferably, it is 5-1000 m ² / g, more preferably 30-700 m ² / g, still more preferably 50-4.
It is 00 m ² / g.

As the inorganic fine particles, various alumina (α, γ, δ, etc.), metal oxides such as silica, titanium oxide, zirconia, iron oxide and chromium oxide, calcium carbonate, magnesium carbonate, aluminum silicate, talc, Examples thereof include mica, zirconium phosphate, calcium phosphate, barium sulfate, and ultrafine metal particles such as gold, silver, and platinum, but are not limited to these as long as the specific surface area is satisfied. More preferred are alumina (α, γ, δ), silica, titanium oxide, zirconia, calcium carbonate, magnesium carbonate, and aluminum silicate.

Further, the average particle size of the inorganic fine particles is
It is preferably 0.001 to 5.0 μm. 0.0
If it is less than 01 μm, secondary agglomeration is likely to occur and the apparent particle size becomes large, and when it exceeds 5.0 μm, it becomes coarse projections and roughens the surface when formed into a film. More preferably, it is 0.01 to 2.0 μm. The addition amount is 0.01 to 5.0% by weight with respect to the copolymerized polyester.
It is necessary to be. If it is less than 0.01% by weight, the background reinforcing effect is not sufficient, and if it exceeds 5.0% by weight, the surface becomes rough and wear resistance is deteriorated. It is preferably 0.05 to 4.0% by weight, more preferably 0.08 to
It is 3.5% by weight.

Next, a method of incorporating inorganic fine particles into the copolyester used in the present invention is not particularly limited, but a method of polymerizing the polymer in the presence of particles or a biaxial method. There are a method using an extruder and a method using a mixing roll when the amount is small. For example, it is dispersed in the form of a slurry of ethylene glycol, which is a kind of monomer, and then mixed with other diol components and then polymerized with a predetermined dicarboxylic acid component. A method of kneading with a shaft extruder can be used. As a method for adjusting the content of particles, a high-concentration master is prepared by the above method, and the content of particles is adjusted by diluting it with a thermoplastic polymer that does not substantially contain particles during film formation. The method of doing is effective.

Next, an example of producing the film of the present invention will be described. For example, after drying the pelletized copolyester composition obtained by the above-mentioned method as needed, it is supplied to a known melt extruder, and the melting point of the polymer or more, from the slit die at the decomposition point or less. It is extruded into a sheet and cooled on a casting roll to make an unstretched film. Next, this unstretched film is first stretched in the longitudinal (MD) direction. At this time, 3.0 to 1 at a temperature higher than the glass transition point (Tg) of the copolyester composition by 20 ° C. or more.
Stretching is performed at 0.0 times, preferably 30 ° C. or higher. As a result, the effects of improving wear resistance and mechanical properties of the present invention are exhibited. Further, the film is stretched in the width (TD) direction for biaxial orientation, but 2.0 to 8.0 at a temperature higher than Tg by 5 ° C. or more.
Double stretched. Stretched area ratio (MD direction stretch ratio and TD
It is preferably 6.0 to 30.0 times. After this, it may be further stretched in the MD direction.
This stretched film may be further heat treated, the heat treatment temperature is 150 to 250 ° C., and the heat treatment time is 0.5 to 12
A range of 0 seconds is preferred.

The plane orientation index P of the film obtained as described above (the refractive index in the longitudinal direction, the width direction and the depth direction of the film is measured using an Abbe refractometer, and each value is nx. , Ny, and nz are obtained by the following formula.) P = (nx + ny-2nz) / 2 requires 0.15 or more. If it is less than this range, the effects of improving the wear resistance and mechanical properties of the present invention cannot be sufficiently obtained.
Preferably, it is 0.16 or more.

The tensile speed of the film of the present invention is 3
It is preferable that the ratio of 0 mm / min and the strength at 1% elongation measured at 300 mm / min, that is, (F-1) _R is 0.7 or more in at least one of MD and TD. . If it is smaller than this, the magnetic recording tape, the printer ribbon, the sheet, or the like, to which tension is applied for a long time, may be deformed and may not be used.

[0022]

EXAMPLES Next, the embodiments of the present invention will be explained based on examples, but the invention is not limited thereto. In addition, the measuring method of the characteristic in an Example is as follows.

(1) Plane Orientation Index (P) The refractive index in the longitudinal direction, width direction and thickness direction of the film was measured using an Abbe refractometer, and the respective values were measured as nx,
When ny and nz were used, it was calculated by the following formula. P = (nx + ny-2nz) / 2 (2) Strength, Young's modulus, (F-1) _R Unless otherwise specified, the TRS type tensile tester has a width of 10
mm, length 50 mm, tensile speed 300 mm / min. In addition, (F-1) _R is a tensile speed of 30 mm / min and 30
It is the ratio of the strength at an elongation of 1% measured at 0 mm / min. That is,

[Equation 1] Calculated at.

(3) Abrasion Resistance and Dynamic Friction Coefficient Abrasion resistance is obtained by molding the obtained copolyester into a film and fixing a tape-shaped roll slit into a narrow width on a stainless steel (SUS-304) guide roll. Rubbing was carried out at a high speed with tension (traveling speed of 1000 m / min) for 1 hour, and ranked according to the amount of white powder generated on the surface of the guide roll. Class A: No white powder is generated B Class: White powder is generated C Class: White powder is often generated Also, the coefficient of dynamic friction is measured from the tension on both sides sandwiching the metal guide when the film is running, and 0.25 or less is judged to be good slipperiness. did.

(4) Average Particle Size of Inorganic Fine Particles A particle slurry was prepared and measured using a centrifugal sedimentation type particle size measuring apparatus (CAPA500 manufactured by Horiba, Ltd.).

(5) Specific Surface Area of Inorganic Fine Particles It was measured by the BET adsorption method using nitrogen gas.

(6) Glass transition point (Tg) Differential calorimeter (DSC-1 manufactured by Perkin-Elmer)
Using B), the temperature was raised at 16 ° C./min for measurement.

(7) Intrinsic viscosity O-chlorophenol was used as a solvent and measured at 25 ° C.

Reference Example 1 Production of bis (p-methoxycarbonylphenyl) terephthalate (BMT) 2.2 mol of methyl p-hydroxybenzoate (p-MHB), acetic anhydride 2. per mol of terephthalic acid (TPA). 5 mol was charged into a reaction tank equipped with a nitrogen introduction tube, a thermometer, and a stirrer, and gradually heated under nitrogen while stirring,
The temperature was raised to 250 ° C. in 5 hours. Acetic acid started to flow out at around 150 ° C, and when it reached 250 ° C, the system became transparent. After further holding at 250 ° C. for 30 minutes, the reaction was completed and the mixture was filtered through a 400-mesh wire net. The obtained reaction product was cooled, then pulverized into a powder form, washed twice with acetone, and dried under reduced pressure. When analyzed by NMR, it was confirmed that the structure was as shown in Table 1, and it was found that the reaction occurred almost quantitatively and BMT was obtained.

[0030]

[Table 1] Reference Examples 2 to 6 In Reference Example 1, TPA and p-MHB were each replaced by the raw material as shown in Table 1, and the same results were obtained under the same conditions. confirmed.

Example 1 First, 90 mol% of dimethyl terephthalate (DMT) was used as the compound represented by the raw material (IV) of the unit (II), and the raw material (III) of the unit (I) produced in Reference Example 1 was used. The compound shown is 10 mol% of BMT, 0.06% by weight of magnesium acetate as a catalyst in ethylene glycol (EG) in a double amount (ie 200 mol%) with respect to these carboxylic acid components (based on the polymer obtained). Was added and heated under a nitrogen stream (up to 230 ° C.) and stirred to carry out a transesterification reaction. After the reaction was completed, antimony trioxide (0.
03% by weight (based on the polymer obtained), trimethyl phosphate 0.03% by weight (based on the polymer obtained), and silica 0.3 having a specific surface area of 200 m ² / g and an average particle size of 0.3 μm. % By weight (based on the polymer obtained) was added as an EG slurry (silica concentration 10% by weight) and the temperature was raised to 290 ° C. in 2 hours while 0.5 mmHg in 1.5 hours.
The pressure was further reduced to 0, polymerization was further performed at 290 ° C. and 0.5 mmHg for 1 hour, and then the polymer was taken out. The intrinsic viscosity is 0.63 g / dl, and the Tg measured by DSC is
It was 70 ° C.

Next, at 290 ° C., an extruder was used to extrude from a T die onto a casting drum having a surface temperature of 60 ° C.,
An unstretched film was produced. This unstretched film is
It was stretched 4.0 times in the MD direction at 2 ° C. This stretching was carried out in three stages with the difference in peripheral speed between each pair of rolls. This uniaxially stretched film was stretched in a TD direction at 95 ° C. using a stenter.
After being stretched 0 times, it was rolled up. The properties of the obtained film were excellent as shown in Table 2.

[0033]

[Table 2]

[Table 3] In the table, TPA: terephthalic acid, EG: ethylene glycol, BD: butanediol, * 1: (MD + T
Calculated as a value of D) / 2, * 2: indicates a value in the MD direction.

Examples 2 to 10 In Example 1, the copolyester raw material, the kind and amount of particles, etc. were changed as shown in Table 2, and the MD stretching temperature was 30 ° C. higher than the Tg of the polymer and the TD stretching temperature was changed. Was higher than the Tg of the polymer by 25 ° C. and stretched in the same manner as in Example 1 to obtain a film. It had the excellent properties shown in Table 2.

Comparative Example 1 A film was prepared in the same manner as in Example 1 except that the MD stretching temperature was 85 ° C., and the plane orientation index of the film was outside the range of the present invention. As shown, the film had good abrasion resistance but poor mechanical properties.

Comparative Example 2 A film was prepared in the same manner as in Example 5 except that the inorganic fine particles were not added. As shown in Table 2, the mechanical properties were good, but the abrasion resistance was poor. .

Comparative Example 3 A film was prepared in the same manner as in Example 10 except that the stretching ratio was set to MD 2.8 times and TD 1.8 times. However, as shown in Table 2, the plane orientation index is outside the scope of the present invention. The film had poor mechanical properties and abrasion resistance.

[0038]

EFFECT OF THE INVENTION The film of the present invention is excellent in mechanical properties, particularly in the case of being subjected to tension, and is also excellent in abrasion resistance and moldability. Therefore, even if it is thin, it is excellent in handleability during handling, and is particularly suitable for use in applications where tension is applied for a long time, for example, a base film such as a magnetic recording medium or a printer ribbon, in which deformation is unlikely to occur. Also, even if it comes in contact with metal, it cannot be scraped. Furthermore, it is also suitable for electric insulating materials such as capacitors and FPCs and packaging materials.

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Claims (1)

[Claims] 1. Units I and II represented by the following formula: (In the formula, Ar ₁ , Ar ₂ , Ar ₃ and Ar ₄ independently represent a divalent aromatic residue, and R ₁ and R ₂ are independently linear or branched having 1 to 12 carbon atoms. Represents a cyclic or cyclic divalent aliphatic, and x and y satisfy the following formulas (1) and (2): x + y = 1 (1) 0.02 ≦ x ≦ 0.70 (2)
And a copolymerized polyester film containing 0.01 to 5.0% by weight of the inorganic fine particles having a specific surface area of 1 m ² / g or more with respect to the copolymerized polyester. A copolyester film in which the plane orientation index of the polyester film is 0.15 or more.