JPH06145488A - Polyester composition and film made thereof - Google Patents

Abstract

(57) [Summary] [Structure] A polyester composition containing a polymer particle comprising a polycondensate of a polyhydric alcohol and a polybasic acid, at least one of which is trivalent or more, and a film comprising the same. [Effect] Since the thermoplastic polyester composition of the present invention has excellent affinity of the polymer particles contained therein with polyester, when formed into a film, the particles are less likely to fall off during high-speed running, and magnetic surface scratches due to the particles occur. Hard to do. Therefore, it is possible to prevent the generation of white powder due to the falling of particles, deterioration of magnetic surface scratches, etc., and to prevent process contamination during the production of the film, and particularly to enable suitable use as a product such as a magnetic tape. Is.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyester composition having excellent abrasion resistance and magnetic scratch resistance when formed into a film, especially during high speed running, and a film comprising the same.

[0002]

2. Description of the Related Art Generally, polyester such as polyethylene terephthalate has excellent mechanical properties and chemical properties, and is widely used as a molded product such as a film or a fiber. When the polyester molded product is processed and used, its slipperiness and abrasion resistance greatly affect the workability in the manufacturing process and the processing process in various applications. For example, when they are used as a base film of a magnetic tape, if their properties are insufficient, friction between the coating roll and the film is increased during the manufacturing process of the magnetic tape, and the film is wrinkled or scratched. In addition, the friction powder of the film is apt to be generated, and coating omission occurs in the step of applying the magnetic layer, and as a result, magnetic recording omission (drop-out) is caused. In addition, the magnetic and non-magnetic surfaces rub against each other during the winding after the magnetic agent application / calendering process, causing scratches on the magnetic surface, resulting in a drop in image quality such as drop-out when used as a product. ing.

Conventionally, as a method for improving the slipperiness of a film, many proposals have been made to incorporate inorganic particles such as titanium dioxide, calcium carbonate and silicon dioxide into polyester. However, since these inorganic particles have a low affinity with polyester, for example, when used as a film, a calendar process in the step of applying a magnetic layer, contact with a roll during film travel, and a film during winding. When an external force is applied by mutual contact, they easily fall off, which may cause scrapes, deterioration of slipperiness and scratches on the surface. In this way, many scraps are generated,
If the surface is scratched, it may cause coating failure in the step of applying the magnetic layer and drop-out during use. Further, stains on the calendar roll in the step of applying the magnetic layer significantly deteriorate the workability in producing the magnetic recording film. As described above, it has been desired to improve the magnetic surface scratches and the sharpness caused by the low affinity with polyester.

As a method for improving the affinity between particles and polyester, surface treatment of inorganic particles and use of organic particles have been proposed. As the surface treatment of the inorganic particles, for example, the surface treatment with a polyacrylic acid-based polymer described in JP-A-63-128031 and JP-A-62-235 can be used.
353 and JP-A-63-234039, surface treatment with a phosphorus compound, JP-A-62-223239 and JP-A-63-313345, surface treatment with a coupling agent, JP-A-63-304038. Surface treatment with a silane compound, JP-A-63-280763.
Although the surface treatments by grafting with glycol have been proposed in the publications, it is difficult to obtain sufficient affinity even if these methods are adopted, and the abrasion resistance is not sufficient. Various organic particles have been proposed, for example, JP-A-49-117550 (polyethylene terephthalate particles, poly-1,4-bis (hydroxymethyl) cyclohexane terephthalate particles), JP-A-61. -174254 (melamine /
Formaldehyde copolymer particles, phenol / formaldehyde copolymer particles, etc.), JP-A-2-189359
Japanese Patent Publication (vinyl compound / divinylbenzene copolymer particles, dicarboxylic acid / acrylate copolymer particles, etc.) can be mentioned, but even with these organic particles, in applications requiring high abrasion resistance, However, the affinity with polyester was insufficient, and the abrasion resistance was insufficient when used as a product.

[0005]

DISCLOSURE OF THE INVENTION As a result of intensive investigations by the present inventors, by using polymer particles having a specific composition, abrasion resistance and magnetic surface scratches at high speed when a film is formed are obtained. It has been found that can be significantly improved. An object of the present invention is to eliminate the above-mentioned drawbacks of the conventional techniques, and to provide a polyester composition which is excellent in abrasion resistance during high speed running when formed into a film, and in magnetic surface scratch resistance. .

[0006]

The above-mentioned object of the present invention is to provide polymer particles having an average particle diameter of 0.01 to 5 μm to 0.0
A polyester composition comprising, as a main component, an aromatic dicarboxylic acid and a glycol, which are contained in an amount of 05 to 10% by weight, wherein the polymer particles include a polyhydric alcohol in which at least one is trivalent or more and a polybasic acid. This is achieved by a polyester composition characterized by comprising a polyester resin as a main constituent and a film comprising the same.

The polyester used in the present invention is produced from a dicarboxylic acid containing an aromatic dicarboxylic acid as a main acid component and an ester-forming derivative thereof and a glycol. Examples of the aromatic dicarboxylic acid in the present invention include terephthalic acid, 2,6-naphthalenedicarboxylic acid, diphenyldicarboxylic acid and isophthalic acid. Examples of the glycol component in the present invention include aliphatic glycols such as ethylene glycol, butanediol, tetramethylene glycol and hexamethylene glycol, and alicyclic diols such as cyclohexanedimethanol. As the polyester in the present invention, for example, those containing alkylene terephthalate or alkylene naphthalate as a main constituent component are preferable. Further, these polyesters may be homopolyesters or copolyesters. Examples of the copolymerization component include aliphatic dicarboxylic acids such as adipic acid and sebacic acid, alicyclic dicarboxylic acids such as hexahydroterephthalic acid and hexahydroisophthalic acid, polyethylene glycol, polypropylene glycol, 5-sodium sulfoisophthalic acid. And so on.

The polymer particles of the present invention include a polyhydric alcohol (A) and a polybasic acid (B), at least one of which is trivalent or more.
It is composed of a polyester resin whose main constituents are and.

The polybasic acid (B) is a compound having at least two carboxyl groups in one molecule, specifically, terephthalic acid, 2,6-naphthalenedicarboxylic acid, diphenylcarboxylic acid, isophthalic acid. , Phthalic acid,
Examples thereof include succinic acid, adipic acid, sebacic acid, and ester-forming derivatives thereof.
Examples of the compound having a valency or higher include hemimellitic acid, trimesic acid, trimellitic acid, prenitic acid, pyromellitic acid, melophanoic acid, and ester-forming derivatives thereof. Particularly, as the polybasic acid (B),
Preference is given to terephthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, succinic acid, trimellitic acid, pyromellitic acid or their ester-forming derivatives.

The polyhydric alcohol (A) is a compound having at least two hydroxyl groups in one molecule, and specifically, ethylene glycol, diethylene glycol, butanediol, propylene glycol, trimethylene glycol, tetramethylene glycol. , Hexamethylene glycol, cyclohexanedimethanol, and the like, and as trivalent or higher valent compounds, glycerin, trimethylolethane, trimethylolpropane, trimethylolbutane, trimethylolbenzene,
Hexanetriol, pentaerythritol, sorbit, tetramethylolcyclohexanol and the like can be mentioned. In particular, ethylene glycol, glycerin, trimethylolethane and pentaerythritol are preferable.

As a method for obtaining a condensate from the polyhydric alcohol (A) and the polybasic acid (B), a conventionally known method for synthesizing a polyester resin can be used. Further, the polyhydric alcohol (A) or the polybasic acid (B) may be composed of plural kinds of compounds.

The polymer particles comprising the condensate are prepared by crushing pellets of the condensate with a medium mill such as a roll mill, a sand mill or a ball mill, or by classifying the pellets with a decanter, or by synthesizing the condensate. It can be obtained by a method of directly preparing fine particles by carrying out the reaction in a solvent inert to the polyhydric alcohol (A) and the polybasic acid (B).

The average particle size of the polymer particles of the present invention is 0.0
It is 1 to 5 μm, preferably 0.03 to 1 μm. 0.
When the thickness is less than 01 μm, the slipperiness when formed into a film is insufficient, and when it exceeds 5 μm, the abrasion resistance targeted by the present invention is not exhibited.

The content of the crosslinked polymer particles of the present invention in the polyester composition is 0.005 to 10 parts by weight, preferably 0.01 to 5 parts by weight, based on 100 parts by weight of the polyester.

Regarding the method of adding the polymer particles to the polyester and the timing of the addition, a conventionally known method, for example, a method of adding to the polyester reaction system in the form of powder or glycol slurry, powder or low boiling point It is possible to employ a method in which the polyester is kneaded in the form of slurry using a solvent. When polymer particles are added as a slurry system to a reaction system or a polymer, anionic surfactants such as sodium dodecylbenzenesulfonate and sodium lauryl sulfate, polyoxyethylene nonylphenyl ether, polyethylylene glycol monostearate. Nonionic surfactants such as, and polyvinylpyrrolidone, polyvinyl alcohol, and dispersants such as carboxymethyl cellulose may be included.

Further, the polyester of the present invention can be used as a metal compound catalyst or a coloring preventing agent for compounds such as lithium, sodium, calcium, magnesium, manganese, zinc, antimony, germanium and titanium which are usually used in the production of polyester. Phosphorus compound, in addition to the polymer particles of the present invention, inorganic particles such as aluminum oxide, zirconium oxide and calcium carbonate, or a polyester polymerization reaction system containing at least one of alkali metal and alcal earth metal and phosphorus as a part of the constituent components. It may also contain particles precipitated in step 1, that is, inert particles such as internal particles. Further, plural kinds of polymer particles of the present invention may be contained at the same time.

As a method for producing a composition containing inorganic particles or internal particles and polymer particles, for example, a method of adding both of them to a reaction system of polyester can be used, or each particle can be separately added to a polymer. It is also possible to use a method of blending a master chip in which is blended and melt-kneading.

The polyester composition of the present invention can be applied to both a single layer film and a laminated film, but from the viewpoint of running property and abrasion resistance, at least one film comprising the composition of the present invention is laminated. Films are preferred. The laminated film mentioned here has a structure of at least two layers in the thickness direction of the film, and a film having a structure of three or more layers also falls into this category. Further, it is preferable that at least one outermost surface layer is made of the polyester film of the present invention from the viewpoint of running property. A laminated film having both sides of the polyester film of the present invention is particularly preferable.

Various forms of the laminated film are possible. For example, in the case of a two-layer laminated film, a layer (X layer) containing the polymer particles of the present invention and another layer (Y
Layer), a laminated structure in which a coating layer (for example, an easily adhesive layer) is provided on the surface of the X layer, a laminated structure in which a coating layer (for example, an easily adhesive layer) is provided on the surface of the Y layer,
A laminated structure in which a back coat layer is provided on the surface of the Y layer can be adopted. In the case of a three-layer laminated film, a three-layer laminated structure of X layer / Y layer / X layer is simply formed, a laminated structure in which a coating layer is provided on the surface of one X layer of the three-layer laminated structure, and X layers on both sides. A laminated structure in which a coating layer is provided on the surface (both sides of the laminated film) can be adopted. In this case, the thickness of the X layer is preferably 0.1 to 1.5 μm, and the thickness of the coating layer is preferably about 0.01 to 1 μm. In the case of a laminated film having four or more layers, basically, the number of Y layers (intermediate layers) in the above-mentioned three-layer laminated film is simply increased. Is the same as.

In the case of adopting such a laminated film form, assuming that the thickness of the laminated film is t (μm), the following relationship is established between the average particle diameter D (μm) of the polymer particles of the present invention. It is preferable that 0.1 ≦ t / D ≦ 100

A method for producing such a composite film will be specifically described. First, polyester pellets were mixed at a predetermined ratio, dried, then fed to a known melt lamination extruder, extruded into a sheet from a slit die,
An unstretched film is prepared by cooling and solidifying on a casting roll. That is, 2 or more extruders, 2
Layers are stacked using a manifold or a merging block (for example, a merging block having a square merging portion), two or more layers of sheets are extruded from a die, and cooled by a casting roll to produce an unstretched film. In this case, it is necessary to install a static mixer, a gear pump in the polymer flow path, or to lower the melting temperature of the extruder for extruding the polymer on the outermost surface layer side by 5 to 10 ° C. from the base layer side.
It is effective in improving the uniformity of film thickness.

Next, the unstretched film is biaxially stretched and biaxially oriented. As a stretching method, a sequential biaxial stretching method or a simultaneous biaxial stretching method can be used. However, a sequential biaxial stretching method of first stretching in the longitudinal direction and then in the width direction is used, and stretching in the longitudinal direction is performed in three or more stages, and the total longitudinal stretching ratio is 3.5 to 6.5 times. The method is particularly preferred. The stretching temperature in the longitudinal direction varies depending on the type of polyester and cannot be generally stated.
It is effective to set the temperature to 130 ° C. and raise the temperature from the second stage onward. Longitudinal stretching speed is 5000-50000%
A range of / minute is preferred. As a stretching method in the width direction, a method using a stenter is generally used. Draw ratio is 3.0
The range of up to 5.0 times is suitable. Stretching speed in the width direction is 1
The range of 000 to 20000% / min and the temperature of 80 to 160 ° C are suitable. Next, this stretched film is heat-treated. The heat treatment temperature in this case is 170 to 220 ° C., especially 1
The range of 80 to 200 ° C. and the time of 0.2 to 20 seconds are suitable.

As the surface roughness of the film, a surface roughness parameter Rt / Ra which is a ratio of the center line average roughness Ra and the maximum height Rt is preferably 40 or less, more preferably 30 or less,
It is particularly preferably 20 or less in terms of good abrasion resistance. Further, regarding the distribution of the height of surface protrusions of the film of the present invention, one having a height of 20 nm or more is defined as a protrusion height, and when the relative standard deviation is 1.0 or less, the protrusion height is uniform. And the sharpness are good, which is preferable.

The method for measuring the physical properties and the method for evaluating the effect in the present invention are as follows. A. Particle characteristics (1) Particle size Photograph of particles in a polymer or film at 20,000 to 50,000 times under an electron microscope (photo size 8c
m × 10 cm (30 sheets) was performed, the circle equivalent diameter of the polymer particles was measured, and the number-based average particle diameter was determined.

B. Polymer Properties (1) Intrinsic Viscosity Measured at 25 ° C. using o-chlorophenol as a solvent.

C. Film characteristics (1) Surface roughness parameters Ra and Rt Measured using a high precision thin film step measuring instrument ET-10 manufactured by Kosaka Laboratory. Ra is the center line average roughness, Rt is the maximum height, and represents the distance between the maximum peak and the deepest valley of the roughness curve. The measurement conditions are as follows, and the average value of 20 measurements was taken as the value.・ Stylus tip radius: 0.5 μm ・ Stylus load: 5 mg ・ Measurement length: 1 mm ・ Cut-off value: 0.08 mm For details of the definition of each parameter, see Jiro Nara "Measurement of surface roughness- Evaluation method "(General Technology Center, 1
983).

(2) Laminated Thickness When the most abundant particles in the film are crosslinked polymer particles, XPS (X-ray photoelectron spectroscopy), IR (infrared spectroscopy) or confocal microscope is used while etching from the surface. And measure the depth profile of the particle concentration. In the surface layer of the film laminated on one side, the particle concentration is low due to the interface of the surface, and the particle concentration increases as the distance from the surface increases.

In the case of the film laminated on one side of the present invention, the particle concentration once reaching the maximum value at the depth [I] starts to decrease again. Based on this concentration distribution curve, the depth [II] (II> I here), which is 1/2 of the maximum particle concentration, was defined as the layer thickness. Furthermore, for other laminated films,
The same analysis was performed from the point where the particle concentration appears. Furthermore, when inorganic particles are contained,
Using a secondary ion mass spectrometer (SIMS), the concentration ratio (M ⁺ / C ⁺ ) of the element resulting from the highest concentration of particles in the film and the carbon element of polyester is defined as the particle concentration, and the polyester X The depth (thickness) analysis is performed from the surface of the layer. Then, the laminated thickness can be obtained from the same method as described above. It can be also obtained by observing the cross section of the film or a thin film step measuring instrument.

(3) Runnability A tape runnability tester TBT-300 type [manufactured by Yokohama System Laboratory Co., Ltd.] was slit into a film width of 1/2 inch.
Was run at 20 ° C. and 60% RH, and the initial friction coefficient μk was determined by the following formula. The guide diameter is 6
mmφ, the guide material is SUS27 (surface roughness 0.
2S), winding angle is 180 °, traveling speed is 3.3 cm
/ Sec. μk = 0.733 × log (T ₁ / T ₂ ) T ₁ : Outlet tension T ₂ : Inlet tension The above μk is 0.35 or less has good slipperiness. Here, if μk is larger than 0.35, the slipperiness during film processing or as a product becomes extremely poor.

(4) Scrapability (high speed running) A tape-shaped roll obtained by slitting a film into 1/2 inch is wound around a stainless steel SUS-304 guide roll at an angle of 60 °, a speed of 250 m / min, and a tension of 95 g for 50 minutes.
It was rubbed over 0 m and ranked as follows according to the amount of white powder generated on the surface of the guide roll. Grades A and B were accepted. Class A: No white powder is generated B Class: White powder is slightly generated Class C: White powder is slightly large Class D: White powder is large

(5) Magnetic surface scratch A commercially available video tape with a magnetic surface of 100 g and a tension of 100 g
Then, wind the longitudinal direction of the tape around the circumference of a pin having a diameter of 7 mm. Further, an evaluation film slit into a tape shape having a width of 1/2 is overlapped and wound around the length of the video tape at a wrapping angle of 120 ° and a tension of 50 g, and the evaluation film is made to travel 5 cm 10 times at a running speed of 200 cm / min. . At this time, the scratches on the magnetic surface were observed with a differential interference microscope at an observation magnification of 50 times. When there were almost no scratches, the magnetic scratches were good, and when there were 20 or more scratches, the magnetic scratches were defective. And

[0032]

The present invention will be described in more detail with reference to the following examples. Example 1 Polycondensation reaction of phthalic anhydride and glycerin in which polyethylene terephthalate chips having an intrinsic viscosity of 0.670 dl / g were made into a molten state using a vent type twin-screw extruder and dispersed as a 20 wt% concentration water slurry. The polymer particles having an average particle diameter of 0.5 μm obtained in Step 1 are added so as to be 0.5% by weight in the polyester composition. Ventoro is maintained at a vacuum of 10 Torr and the resin temperature is 280
Melt extrusion was performed at 0 ° C. to obtain a polyethylene terephthalate composition (I) containing polymer particles. The intrinsic viscosity of the obtained polymer was 0.620 dl / g.

This polyethylene terephthalate composition (I) was melt extruded at 290 ° C. to obtain an unstretched film by using an electrostatic cast method. Then 4 in the longitudinal direction
After stretching twice and 3.6 times in the width direction, it was heat-treated at 200 ° C. for 5 seconds under a constant length to obtain a film having a thickness of 10 μm. This film has Ra = 0.013 and Rt =
0.270, the slip property was μk = 0.23, the sharpness was class A, and the magnetic surface scratch was good.

Example 2 A film was obtained in the same manner as in Example 1 except that polymer particles obtained by polycondensation reaction of phthalic acid and pentaerythritol were used. As shown in Table 1, abrasion resistance,
The magnetic surface scratches were also good.

Example 3 A polyethylene terephthalate composition (III) was obtained in the same manner as in Example 1 except that polymer particles having a composition of terephthalic acid / trimellitic acid / ethylene glycol were used.

On the other hand, 100 parts by weight of dimethyl terephthalate, 70 parts by weight of ethylene glycol, 0.06 parts by weight of magnesium acetate as a transesterification reaction catalyst, 0.03 parts by weight of antimony trioxide as a polymerization catalyst, and trimethyl phosphate of 0 as a heat resistance stabilizer. Using 0.03 parts by weight,
Polyethylene terephthalate (II) having an intrinsic viscosity of 0.650 dl / g was obtained by a usual method. Then, the polyethylene terephthalate composition (III) is melt extruded at 290 ° C. onto the polyethylene terephthalate (II),
A laminated unstretched film was formed using an electrostatically applied casting method.

This unstretched film was stretched in the longitudinal direction at 120 ° C.
And stretched 3.9 times. This uniaxial film was stretched 3.6 times in the width direction at 111 ° C. using a stenter and heat-treated at 200 ° C. for 5 seconds under a fixed length to give a film having a thickness of 10.0 μm (laminated thickness 1.0 μm). Obtained. As shown in Table 1, the content of the polymer particles in the laminated portion of the obtained film was 0.6% by weight, and the film characteristics were Ra = 0.013 and Rt = 0. 270, μk =
0.23, abrasion resistance class A, and good magnetic surface scratches.

Comparative Example 1 A film was obtained in the same manner as in Example 1 by using spherical silicon dioxide particles having D = 0.45 μm, and as shown in Table 2, the affinity was low and many particles fell off and were scraped. The grade was C and the magnetic surface was defective.

Comparative Example 2 Example 1 was carried out using crosslinked polymer particles produced using commercially available divinylbenzene (divinylbenzene 55%, ethylvinylbenzene 40%, ethylbenzene 5%) (degree of crosslinking 55%). When a film was formed in the same manner as in, the sharpness deteriorated as shown in Table 2.

Comparative Examples 3 to 4 Films were obtained by changing the particle size or addition amount of the particles in Example 1, but as shown in Table 2, abrasion resistance and magnetic surface scratches were deteriorated.

[0041]

[Table 1]

[Table 2]

[0042]

Since the thermoplastic polyester composition of the present invention contains polymer particles of a specific composition, it has an excellent affinity between the particles and polyester, and therefore, when formed into a film at high speed running. Particles are less likely to fall off, and magnetic surface scratches due to particles are less likely to occur. Therefore, it is possible to prevent the generation of white powder due to the falling of particles, which is a problem when adding various particles in the past, and to prevent the deterioration of magnetic surface scratches, the prevention of process contamination during the production of the film, and especially the magnetic property. It enables suitable use as a product such as a tape.

Claims (2)

[Claims] 1. A polyester composition comprising 0.005 to 10% by weight of polymer particles having an average particle diameter of 0.01 to 5 μm as main constituents of an aromatic dicarboxylic acid and glycol. At least one of the particles is 3
A polyester composition comprising a polyester resin mainly composed of a polyhydric alcohol having a valency or more and a polybasic acid. 2. A film comprising the polyester composition of claim 1.