JPH0675956B2 - Polyester film laminate and method for producing the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyester film laminate containing an underlayer and a method for producing the same, and more particularly, to a smooth and adhesive composition to various magnetic layer compositions when used as a film for magnetic recording media. A polyester film laminate having good properties and a method for producing the same are provided.

[0002]

2. Description of the Related Art A base film for a magnetic recording medium usually contains particles in the base film, and the size of the particles,
By controlling the distribution etc., smoothness to the extent that recording defects do not occur, and on the other hand, the slipperiness required for handling the base film is imparted in a good balance. On the other hand, the adhesion of the magnetic layer to the base film is also required, and such adhesion is imparted in the base film manufacturing process, or after the base film manufacturing or in the pre-process in the magnetic coating process.

[0003]

By the way, when used as a magnetic recording medium, a base film having both smoothness to the extent that recording defects do not occur, slipperiness required for handling the base film and adhesion to the magnetic layer. It has been very difficult to produce the conventional method by the conventional method especially in recent years when a wide variety of magnetic layers are used.

[0004]

Means for Solving the Problems That is, the present invention is (A)
A water-insoluble polyester copolymer formed from a mixed dicarboxylic acid component containing 0.5 to 15 mol% of a sulfonic acid metal group-containing dicarboxylic acid in all dicarboxylic acid components and a glycol component, (B) inert particles, ( C) Boiling point 60 to
A water-soluble organic compound at 200 ° C. and (D) water were added to (A) /
(B) A polyester film laminated film characterized in that a polyester resin composition blended in the range of 100,000 / 50 to 50,000 is laminated on at least one side, and the laminated surface satisfies the following formula.

[0005]

[Equation 5]

[0006]

[Equation 6] (SRz, SΔa, and Sλa are ten-point average roughness (μm), average inclination gradient, average wavelength (μm), and PC represent the number of protrusions in an area of 0.12 mm ² in three-dimensional surface roughness measurement, respectively) and melting. 0.5 to 15 of (A) all dicarboxylic acid components on at least one surface of the extruded unstretched polyester film or the uniaxially stretched polyester film.
Water-insoluble polyester copolymer formed from mixed dicarboxylic acid component containing mol% of sulfonic acid metal base-containing dicarboxylic acid and glycol component, (B) inert particles, (C) water-soluble with boiling point of 60 to 200 ° C The organic compound and (D) water are (A) / (B) = 100000/50 to 5
0000, (A) / (C) = 100/20 to 5000,
(C) / (D) = 100/50 to 10,000 The weight ratio of at least the inert particles is ultrasonically dispersed, and the polyester resin composition blended is coated and dried. Further, it is a method for producing a polyester film laminate, which is characterized by biaxially stretching or uniaxially stretching.

[0007]

[Equation 7]

[0008]

[Equation 8] (SRz, SΔa, and Sλa represent ten-point average roughness (μm), average inclination gradient, average wavelength (μm), and PC represent the number of protrusions in an area of 0.12 mm ² in three-dimensional surface roughness measurement, respectively.)

The polyester copolymer (A) contained in the aqueous dispersion of the present invention comprises 0.5 to 15 mol% of a sulfonic acid metal base-containing dicarboxylic acid and 85 to 99 of a sulfonic acid metal base-free dicarboxylic acid. It is a substantially water-insoluble polyester copolymer obtained by reacting a mixed dicarboxylic acid with 0.5 mol% with a glycol component. Substantially water-insoluble means that the polyester copolymer does not dissipate in the hot water even if the polyester copolymer is stirred in hot water at 80 ° C. Specifically, the polyester copolymer is excessive. The weight loss of the polyester copolymer after stirring treatment in hot water of 80 ° C. for 24 hours is 5% by weight or less. As a method for laminating the resin on the polyester, there are a coextrusion method and a coating method, and the latter is more preferable.

Examples of the dicarboxylic acid containing a metal sulfonate group include sulfoterephthalic acid, 5-sulfoisophthalic acid, 4-sulfophthalic acid and 4-sulfonaphthalene-
Examples of the metal salt include 2,7-dicarboxylic acid and 5 (4-sulfophenoxy) isophthalic acid, with 5 being particularly preferable.
-Sodium sulfoisophthalic acid, sodium sulfoterephthalic acid. These dicarboxylic acid components containing a metal sulfonate group are 0.5 to the total dicarboxylic acid components.
˜15 mol%, desirably 2.0 to 10 mol%.
Is. If it exceeds 15 mol%, the dispersibility in water is improved, but the water resistance of the polyester copolymer is significantly lowered,
If it is less than 0.5 mol%, the dispersibility in water is significantly reduced. The dispersibility of a polyester copolymer in water is
The amount of the dicarboxylic acid containing a metal sulfonate group is preferably a small amount, although it varies depending on the copolymerization composition, the type of water-soluble organic compound, the compounding ratio, and the like.

As the dicarboxylic acid containing no metal sulfonate group, aromatic, aliphatic or alicyclic dicarboxylic acids can be used. Examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, orthophthalic acid, 2,6-naphthalenedicarboxylic acid, orthophthalic acid 2,6-naphthalenedicarboxylic acid and the like. It is preferable that these aromatic dicarboxylic acids account for 40 mol% or more of the total dicarboxylic acid components, and if they are less than 40 mol%, the mechanical strength and water resistance of the polyester copolymer will be reduced. Examples of the aliphatic and alicyclic dicarboxylic acids include succinic acid, adipic acid, sebacic acid, 1,3-cyclopentanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4- Examples thereof include cyclohexadicarboxylic acid and 1,4-cyclohexanedicarboxylic acid. Addition of these comparable non-aromatic dicarboxylic acid components may enhance the adhesive performance in some cases, but generally reduces the mechanical strength and water resistance of the polyester copolymer.

The glycol component to be reacted with the mixed dicarboxylic acid is an aliphatic glycol having 2 to 8 carbon atoms or an alicyclic glycol having 6 to 12 carbon atoms, specifically ethylene glycol, 1 , 2-propylene glycol, 1,3-propanediol, 1,4-butanediol, neopentyl glycol, 1,6-hexanediol, 1,2-cyclohexanedimethanol, 1,3
-Cyclohexanedimethanol, 1,4-cyclohexanedimethanol, p-xylylene glycol, diethylene glycol, triethylene glycol and the like. Examples of the polyether include polyethylene glycol, polypropylene glycol, polytetramethylene glycol and the like. Also, an oxycarboxylic acid component such as p-oxyethoxybenzoic acid may be copolymerized.

The polyester copolymer is obtained by usual melt polycondensation. That is, the above-mentioned dicarboxylic acid component and glycol component are directly reacted to distill off water for esterification, and then a direct esterification method is carried out to carry out polycondensation, or dimethyl ester of the above-mentioned dicarboxylic acid component is reacted with glycol component to produce methyl alcohol. Can be obtained by a transesterification method or the like in which the distillate is subjected to transesterification, followed by polycondensation. In addition, solution polycondensation, interfacial polycondensation, etc. are also used, and the polyester copolymer of the present invention is not limited by the polycondensation method. At the time of melt polycondensation, an antioxidant, a slip agent, inorganic fine particles,
An antistatic agent or the like can be added as needed.

In order to obtain an aqueous dispersion of the above polyester copolymer, it is necessary to disperse it in water together with the water-soluble organic compound. For example, the above polyester copolymer and a water-soluble organic compound are premixed at 50 to 200 ° C., and water is added to this mixture and stirred to disperse it, or conversely, the mixture is added to water and stirred to disperse it. Or a method in which a polyester copolymer, a water-soluble organic compound and water are allowed to coexist and stirred at 40 to 120 ° C. The water-soluble organic compound is an organic compound having a solubility of 20 g or more in 1 liter of water at 20 ° C., and specific examples thereof include aliphatic and alicyclic alcohols, ethers and esters.
Ketone compounds, such as methanol, ethanol,
Monohydric alcohols such as isopropanol and n-butanol, glycols such as ethylene glycol and propylene glycol, methyl cellosolve, ethyl cellosolve, n
-Glycol derivatives such as butyl cellosolve, ethers such as dioxane and tetrahydrofuran, esters such as ethyl acetate, and ketones such as methyl ethyl ketone. These water-soluble organic compounds may be used alone or in combination of two or more. Of the above compounds, butyl cellosolve, in terms of dispersibility in water and coatability on a film,
Ethyl cellosolve is preferred.

The above-mentioned (A) polyester copolymer,
It is important that the blending weight ratios of (C) water-soluble organic compound and (D) water satisfy (A) / (C) = 100/20 to 5000 (C) / (D) = 100/50 to 10000. is there. Less water-soluble organic compound than polyester copolymer (A) / (C) 10
If it exceeds 0/20, the dispersibility of the aqueous dispersion is reduced. In this case, the dispersibility can be assisted by adding a surfactant, but if the amount of the surface of the surfactant is too large, the adhesiveness and the water resistance are deteriorated. Conversely (A) /
When (C) is less than 100/5000, or (C) /
When (D) exceeds 100/50, the amount of the water-soluble organic compound in the aqueous dispersion becomes large and the unstretched film or uniaxially stretched film melt-extruded is coated with the aqueous dispersion of the above polyester resin and then stretched in-line. There is a danger of explosion due to the solvent during coating, and it is necessary to take explosion-proof measures for this. In addition, environmental pollution and cost increase, so it is necessary to consider compound recovery. When (C) / (D) is less than 100 / 10,000, the surface tension of the aqueous dispersion becomes large, the wettability to the film is lowered, and coating spots are easily generated. In this case, the wettability can be improved by adding the surfactant, but if the amount of the surfactant is too large, the adhesiveness and the water resistance are reduced as described above.

Further, as the (B) inert particles added to this dispersion, white powder, chalk, heavy calcium carbonate, light carbon carbonate, basic magnesium carbonate, dolomite, special calcium carbonate, kaolin, calcined clay, pyro are used. Philite,
Bentonite, Serisalite, Zeolite, Nepheline / Cinite, Talc, Attapulghanite, Synthetic aluminum silicate, Synthetic calcium silicate, Diatomaceous earth, Silica powder, Contained fine silicic acid, Anhydrous fine silicic acid, Aluminum hydroxide, Barite,
There are various types of inorganic particles such as precipitated barium sulfate, natural gypsum, gypsum, calcium sulfite and other inert particles such as benzoguanamine resin and polystyrene resin, and any one may be used in connection with smoothness and slipperiness. Preferred are natural and synthetic products of silicic acid. Particle size is 0.001μ-3
It is preferable to use the one of μ. If the particle size is less than 0.001 μm, a large amount must be used, and if it exceeds 3 μm, coarse projections occur and conversely the smoothness deteriorates. The amount of (B) used relative to (A) is (A) / (B) = 100000.
The ratio of / 50 to 50,000 is good, and preferably (A) /
(B) = 100000 / 500-10000. These particles include surface-treated particles. It is preferable that these inert particles are ultrasonicated in advance.

Further, the water-acid solution contains an antistatic agent, a lubricant, an organic / inorganic composite crosslinking agent and other resins (polyurethane type), acrylic type, epoxy type, PVA type, cellulose type, polyamide type, rubber type. Etc.) may be used. To apply the aqueous dispersion of the polyester resin thus obtained to the aqueous dispersion of the polyester on the polyester film, to coat the polyester film, the unstretched film obtained by melt extrusion of the polyester film,
Alternatively, it is a uniaxially stretched film. It is not preferable to apply to a biaxially stretched film, because the film is wide and the traveling speed of the film is high, so it is difficult to apply it uniformly.

When the amount of the aqueous dispersion applied to the polyester film is 0.01 to less than 5 g / m ² as a polyester copolymer with respect to the biaxially stretched film, the force for fixing the inactive particles is obtained. Becomes weaker and the durability becomes worse. On the other hand, if the coating amount is more than 5.0 g / m ² , the slip property becomes worse. Further, by applying a corona discharge treatment to the polyester film before applying the aqueous dispersion of the polyester resin, the coatability of the aqueous dispersion is improved,
And the adhesive strength between the polyester film and the polyester copolymer coating is improved. To improve the wettability and adhesiveness of the film surface by subjecting the polyester copolymer layer after in-line coating or after biaxial stretching to corona discharge treatment, corona discharge treatment under nitrogen atmosphere, UV irradiation treatment, etc. You can Further, it is necessary that the polyester film thus produced has a surface satisfying the following formula.

[0019]

[Equation 9]

[0020]

[Equation 10] (SRz, SΔa, and Sλa are ten-point average roughness (μm), average inclination gradient, average wavelength (μm), and PC represent the number of protrusions in an area of 0.12 mm ² in three-dimensional surface roughness measurement.) SRz, SΔa and Sλa were measured with a three-dimensional surface roughness meter manufactured by Kosaka Laboratory Ltd. For the PC, a Nikon differential interference microscope was used to take a photo of the aluminum vapor-deposited polyester film at a final magnification of 160 times, and the projections were traced on a transparent film. The image was made by Nireco Corporation and the polyester film was 0.12 mm.
^This is a numerical value obtained by performing image processing on the area corresponding to ² and calculating the number of protrusions corresponding to a circle. If SRz exceeds 0.5 μm, recording defects such as dropout defects become large,
If the missing level becomes low and it is less than 0.05 μm, it is too smooth and practically difficult to handle. Further, if the left side of the number 10 is less than 0.2, it may cause runnability during processing and other film defects.

In the present invention, a polyethylene terephthalate film is particularly preferable as the polyester film in view of other mechanical properties. As a polyester film, it is preferable that the amount of lubricant is as small as possible in terms of transparency, and preferably 300 ppm.
It is the following. The polyester film obtained by the above method is excellent in adhesiveness, smoothness and gastric smoothness. The film of the present invention can be used for other industrial purposes such as printing and printing for the same purpose.

[0022]

EXAMPLES The present invention will be specifically described below with reference to examples. In the examples, "parts" means "parts by weight". In the peel pack method in the adhesiveness test, an adhesive tape was attached to the surface of the magnetic layer, and after uniformly adhering to the entire surface, the state of instantaneous peeling was observed. The solvent sliding method was performed by observing the state when the surface of the magnetic layer was rubbed 10 times with gauze soaked with tetrahydrofuran. The slipperiness was comprehensively observed in both the running state in the magnetic coating device and the winding state of the film after coating. The smoothness was measured by assembling a floppy disk assembled and measuring the average output of one track with a dropout center SK-444B (manufactured by Shintotsu Engineering Co., Ltd.) (10
The above defects are displayed in FF). The average output was expressed in%. The larger the value, the better.

Example 1 (1) Production of aqueous dispersion of polyester copolymer (A) 117 parts (49 mol%) of dimethyl terephthalate, 117 parts (49 mol%) of dimethyl isophthalate, 103 parts (50 mol of ethylene glycol). %), 57 parts (50 mol%) of diethylene glycol, 0.08 part of zinc acetate and 0.08 part of antimony trioxide in a reaction vessel at 40 to 220 ° C.
The temperature is raised to 3, the transesterification reaction is carried out for 3 hours, and then 5-
9 parts (2 mol%) of sodium sulfoisophthalic acid was added, and an esterification reaction was performed at 220 ° C. to 260 ° C. for 1 hour,
Further, polycondensation reaction was carried out under reduced pressure (10 to 0.2 mmHg) for 2 hours to obtain a polyester copolymer having an average molecular weight of 18,000 and a softening point of 140 ° C. 300 parts of this polyester copolymer and 140 parts of n-butyl cellosolve are stirred in a container at 150 to 170 ° C. for about 3 hours to obtain a uniform viscous melt, and 560 parts of water are gradually added to this melt. After about 1 hour, a uniform protein-colored aqueous dispersion having a solid content of 30% was obtained, and 4500 parts of water and 4500 parts of ethyl alcohol were further added to this to obtain silicon dioxide (SiO 2) having an average primary particle diameter of 0.05 μ. ₂ ) to _{2 based on} the weight of the polyester copolymer
5000 ppm was added, and what was ultrasonically dispersed was added and diluted to obtain a coating liquid having a solid content concentration of 3%.

(2) Production of Coat Film Polyethylene terephthalate is melt extruded at 280 to 300 ° C. and cooled by a cooling roll at 15 ° C. to obtain an unstretched film. This unstretched film is paired with a pair of 85 ° C. having different peripheral speeds. A longitudinal aroma is stretched 3.5 times between the rolls, the uniaxially stretched film is subjected to corona discharge treatment, the above-mentioned coating liquid on the corona discharge treated surface is applied by an air knife method, dried with hot air at 70 ° C., and then, It was stretched 3.5 times in the transverse direction at 98 ° C. with a tenter and further heat-set at 200 to 210 ° C. to obtain a biaxially stretched coated polyester film having a thickness of 75 μm. (Undercoating process: In-line) SRz is 0.2 μm,
The left side of the number 10 was 0.80.

(3) Preparation and coating of magnetic paint 250 parts of γ-Fe ₂ O ₃ derivative powder, 2 parts of dioctyl sulfonate, copolyester (45 mol% terephthalic acid, 20 mol% isophthalic acid, 32.5 sebacic acid) Mol%, 5 sodium sulfoisophthalic acid 2.5 mol%,
Ethylene glycol 50 mol%, neopentyl glycol 50 mol%) 48 parts and cellosolve acetate 60
0 part was mixed using a ball mill for about 24 hours. 400 parts of this mixture 100 parts of copolyester resin, 30 parts of nitrocellulose, vinyl chloride-vinyl acetate copolymer 7
0 parts, 30 parts of polyisocyanate, 400 parts of methyl ethyl ketone, and 400 parts of cyclohexane were added, and the mixture was mixed again for about 70 hours using a pole mill. The resulting mixture is filtered and defoamed, and then coated on the biaxially stretched coated polyester having a thickness of 75 μ obtained above by a gravure coater, smoothed, non-oriented and dried at 80 ° C.,
A film having a coat thickness of 2 μ was obtained. 70 ℃, 75K
It was calendered 8 times at g / cm, left at 60 ° C. for 2 days, punched out to 3.5 inches and ground to assemble a floppy disk. The results are shown in Table 1.

Example 2 The same as Example 1 except that the particle size and the addition amount thereof were changed. The results are shown in Table 1. Example 3 Example 1 was repeated except that the composition of the water-dispersed polyester copolymer was changed as follows. The results are shown in Table 1. Terephthalic acid 48 mol% Isophthalic acid 47 〃 5 Sodium sulfoisophthalic acid 5 〃 Ethylene glycol 40 〃 Neopentyl glycol 60 〃

Comparative Example 1 Example 1 was repeated except that the particle size was changed to 5 μm. The results are shown in Table 1. Comparative Example 2 The procedure of Example 1 was repeated except that the dispersion conditions were changed. The results are shown in Table 1. Comparative Example 3 The procedure of Example 1 was repeated except that the particle size and the amount of addition thereof were changed. The results are shown in Table 1. Comparative Example 4 The procedure of Example 1 was repeated except that the biaxially rolled film of Example 1 was coated. The results are shown in Table 1.

Comparative Example 5 Other evaluations were not carried out because a large number of defects were generated on the magnetic coated surface in which the biaxially stretched film without coating was slippery during the magnetic coating process. The results are shown in Table 1.
From Table 1, it can be seen that according to the present invention, a base film for a magnetic recording medium which is excellent in smoothness, slipperiness and adhesiveness can be obtained.

[0029]

From the results of the above Examples and Comparative Examples, it can be seen that the films obtained according to the present invention have excellent smoothness, slipperiness and adhesiveness.

[0030]

[Table 1]

Continuation of front page (51) Int.Cl. ⁵ Identification number Reference number in the agency FI Technical display location // B29K 67:00 B29L 9:00 4F C08L 67:02 8933-4J (72) Inventor Hajime Suzuki Tsuruga, Fukui Prefecture Masami Kobayashi, Inspector, Tsuruga Branch, Toyobo Co., Ltd., No. 10-24, Toyobo Co., Ltd. General Research Laboratory, Tsuruga Branch (72) Inventor, Osamu Makimura

Claims (2)

[Claims] 1. The total dicarboxylic acid component (A) is 0.5 to 1
A water-insoluble polyester copolymer formed from a mixed dicarboxylic acid component containing 5 mol% of a sulfonic acid metal group-containing dicarboxylic acid and a glycol component, (B) inactive particles (A) / (B) = 100000 / 50-50000
A polyester film composition in which the polyester resin composition blended in a weight ratio of 1 is laminated on at least one side, and the lamination surface satisfies the following formula. [Equation 1] [Equation 2] (SRz, SΔa, and Sλa are ten-point average roughness (μm), average inclination gradient, and average wavelength (μm) in three-dimensional surface roughness measurement, respectively, and PC represents the number of protrusions in an area of 0.12 mm ² . ) 2. 0.5 to 15 mol% of the total dicarboxylic acid component (A) on at least one side of the melt-extruded unstretched polyester film or uniaxially stretched polyester film.
A water-insoluble polyester copolymer formed from a mixed dicarboxylic acid component containing a metal sulfonate-containing dicarboxylic acid and a glycol component, (B) inert particles,
(C) Water-soluble organic compound having a boiling point of 60 to 200 ° C. and (D) water (A) / (B) = 100000/50 to 50
000, (A) / (C) = 100/20 to 5000,
(C) / (D) = 100/50 to 10,000 The weight ratio of at least the inert particles is ultrasonically dispersed, and the polyester resin composition blended is coated and dried. Further, a method for producing a polyester film laminate, which comprises biaxially stretching or uniaxially stretching. [Equation 3] [Equation 4] (SRz, SΔa, and Sλa are ten-point average roughness (μm), average inclination gradient, and average wavelength (μm) in three-dimensional surface roughness measurement, respectively, and PC represents the number of protrusions in an area of 0.12 mm ² . )