JPH07195645A - Laminated polyester film and magnetic recording medium using the same - Google Patents

Abstract

PURPOSE:To improve antistatic capacity and adhesiveness by coating the single surface or both surfaces of a polyester layer having a specific compsn. with a polyester layer having a compsn. different from that of the above mentioned polyester layer by co-extrusion. CONSTITUTION:Polyester A not substantially containing either one of terephthalic acid and naphthalenedicarboxylic acid as a main acidic component and containing an -SO3M group (wherein M is a metal atom having the same equivalent as -SO3, an ammonium group, a quaternary amine group or a quaternary phosphonium group) in its molecule is prepared and polyester B wherein a dicarboxylic acid component containing an -SO3M group is 10-30mol% of a dicarboxylic acid component or/and a glycol component containing an -SO3M group is 10-30mol% of a glycol component and crystalline heat of fusion is 5cal/g or less is prepared. A layer of polyester B is laminated to the single surface or both surfaces of a layer of polyester A by co-extrusion to form a laminated polyester film low in charge properties.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated polyester film, and more specifically to a laminated polyester film which is excellent in antistatic property and adhesiveness and is useful as a magnetic recording medium, packaging material, display material, graphic material, laminated material and the like. The present invention relates to a magnetic recording medium using the same.

[0002]

Polyester films, particularly polyethylene terephthalate and polyethylene-2,6-naphthalene dicarboxylate films, are used in magnetic tapes, floppy disks, magnetic cards, graphic materials, packaging materials and the like. However, since these films are oriented and crystallized, their adhesive strength is low, and they are easily charged, so that practically many restrictions occur.

[0003]

DISCLOSURE OF THE INVENTION An object of the present invention is to provide a magnetic recording medium, a packaging material, which has excellent antistatic performance and adhesiveness.
It is intended to provide a laminated polyester film which can be advantageously used for display materials, graphic materials, laminated materials and the like. Another object of the present invention is to provide a magnetic recording medium using the above film.

[0004]

[Means for Solving the Problems] Terephthalic acid and naphth
Main acid formation of at least one of tarenedicarboxylic acid
Minutes, base-SO₃M (where M is -SO₃Equivalent to
Metal atom, ammonium group, quaternary amine or quaternary
(Indicating a phosphonium group) in the molecule
On one or both sides of the layer (A) consisting of the ester (a)
A group-SO ₃Di containing M (where M is the same as above)
Carboxylic acid component is 10 to 30 mol% of dicarboxylic acid component
Occupy or / and the group -SO₃M (where M is above
The same as the above), the glycol component containing 1 is the glycol component.
Occupies 0 to 30 mol% and has a heat of crystal fusion of 5 cal /
Presence of layer (B) consisting of polyester (b) of g or less
And layer (A) and layer (B) are laminated by coextrusion.
Low-charge laminated polyester film characterized by being
Film is provided.

According to the present invention, there is further provided a magnetic recording medium in which a magnetic layer is provided on at least one surface of the above laminated polyester film.

The above-mentioned invention achieves the above-mentioned object of the present invention. Hereinafter, the present invention will be described in detail, with which other objects, configurations, advantages and effects of the present invention will be apparent.

The layer (A) constituting the laminated polyester film of the present invention contains at least one of terephthalic acid and naphthalenedicarboxylic acid as a main acid component and has a group —SO ₃ M (where M is the same equivalent as —SO ₃ ). Which is a metal atom, an ammonium group, a quaternary amine, or a quaternary phosphonium group) in the molecule.

The polyester (a) preferably contains at least one of terephthalic acid and naphthalenedicarboxylic acid in the acid component in an amount of 70 mol% or more, particularly 75 mol% or more.

The polyester (a) may contain an acid component other than terephthalic acid and naphthalenedicarboxylic acid. As such acid components, aromatic dicarboxylic acids such as isophthalic acid, diphenylketone dicarboxylic acid and anthracene dicarboxylic acid, aliphatic dicarboxylic acids such as adipic acid and sebacic acid, and alicyclic compounds such as cyclohexane-1,4-dicarboxylic acid Dicarboxylic acid etc. can be mentioned.

The polyester (a) preferably contains an aliphatic glycol as a main glycol component, and it is particularly preferable that the aliphatic glycol accounts for 70 mol% or more in the glycol component.

Examples of the aliphatic glycol include polymethylene glycol having 2 to 10 carbon atoms such as ethylene glycol, trimethylene glycol, tetramethylene glycol, pentamethylene glycol, neopentylene glycol, hexamethylene glycol and decamethylene glycol, and cyclohexane. Among them, alicyclic diols such as dimethanol can be mentioned, but ethylene glycol is preferable.

The glycol component may contain a substance other than an aliphatic glycol, and has an aromatic ring such as hydroquinone, resorcin, 2,2-bis (4-hydroxyphenyl) propane, or 1,4-dihydroxydimethylbenzene. Polyalkylene glycol (polyoxyalkylene glycol) such as diol, polyethylene glycol, polypropylene glycol and polytetramethylene glycol, and diethylene glycol may be contained as a glycol component.

The polyester (a) may contain a small amount of a hydroxycarboxylic acid component such as p-hydroxybenzoic acid and p- (β-hydroxyethoxy) benzoic acid in addition to the above-mentioned dicarboxylic acid component and glycol component.

Further, the polyester (a) may contain, in addition to the above-mentioned dicarboxylic acid component, glycol component and hydroxycarboxylic acid component, a polyfunctional component in a small amount in a range in which crosslinking does not substantially occur. Examples of the polyfunctional component include trimellitic acid, dimethylolpropionic acid, glycerin, and trimethylolpropane.

Among such polyesters (a),
Those having alkylene terephthalate and / or alkylene naphthalate as a main repeating unit are preferably used, and in particular, polyethylene terephthalate and polyethylene-2,6-naphthalate, and 70 mol% or more of all dicarboxylic acid components are terephthalic acid and / or 2 A copolymer in which 6,6-naphthalenedicarboxylic acid is used and 70 mol% or more of all glycol components is ethylene glycol is preferable.

As another specific example which can be used as the polyester (a), the acid component comprises terephthalic acid and 2,6-naphthalenedicarboxylic acid, and the glycol component comprises ethylene glycol or ethylene glycol and 1,4-butanediol. And a polybutylene-2,6-naphthalenedicarboxylate having an acid component of 2,6-naphthalenedicarboxylic acid and a glycol component of 1,4-butanediol.

The intrinsic viscosity of polyester (a) (measured in an orthochlorophenol solvent at 35 ° C.) is 0.45 to 0.4.
It is preferably 9 dl / g.

The polyester (a) contains a substance known per se and can be produced by a per se known method.

Since such a polyester (a) has high crystallinity and high strength, the strength of the laminated polyester film of the present invention can be maintained by having the layer (A) composed of the polyester (a).

Another layer (B) constituting the laminated polyester film of the present invention is a group --SO ₃ M (where M
Is a metal atom in the same amount as -SO ₃ , an optionally substituted ammonium group, a quaternary amine, or a quaternary phosphonium group, and has a heat of crystal fusion of 5 cal / g or less (b). Consists of.

Since the polyester (b) contains a group --SO ₃ M and has a low heat of fusion of crystallization, the layer (B) made of the polyester (b) has antistatic ability and excellent adhesiveness to magnetic paints and inks. . Therefore, by using the layer (B) made of the polyester (b) as the surface layer, a laminated polyester film having excellent antistatic properties and adhesiveness can be obtained.

The polyester (b) contains at least one of a dicarboxylic acid component containing the group —SO ₃ M and a glycol component containing the group, and the amount thereof is the amount of the dicarboxylic acid component or glycol constituting the polyester (b). 10 to 30 mol% relative to the components, preferably 11 to 20
It is contained at a ratio of mol%. When the polyester (b) contains the group —SO ₃ M in the above range, the water resistance of the layer (B) made of the polyester (b) is maintained and the antistatic ability is exhibited.

In the group —SO ₃ M, M is the same amount of metal atom as —SO ₃ , an optionally substituted ammonium group,
A quaternary amine or quaternary phosphonium group, an alkali metal atom such as lithium, sodium or potassium,
Alkaline earth metal atoms such as magnesium and calcium are preferred, and sodium and potassium are particularly preferred. Further, M is also preferably an ammonium group, a trialkylammonium group, or a tetraalkylphosphonium group.

As the dicarboxylic acid component containing the group —SO ₃ M and the glycol component containing the group, the following formulas (1) to
(7)

[0025]

[Chemical 1]

[0026]

[Chemical 2]

Examples thereof include compounds represented by: These may be used alone or in combination of two or more.

Other dicarboxylic acid components constituting the polyester (b) include terephthalic acid, phthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, diphenylketone dicarboxylic acid, 4,4'-diphenyldicarboxylic acid and anthra. Examples thereof include aromatic dicarboxylic acids such as sendicarboxylic acid, aliphatic dicarboxylic acids such as adipic acid and sebacic acid, alicyclic dicarboxylic acids such as cyclohexane-1,4-dicarboxylic acid, and other dimer acids. These may be contained in one or more polyesters (b). The polyester (b) may further contain maleic acid, fumaric acid, itaconic acid and the like together with the above dicarboxylic acid as an acid component.

As other glycol components constituting the polyester (b), ethylene glycol, trimethylene glycol, tetramethylene glycol (1,4-butanediol), pentamethylene glycol, neopentylene glycol, hexamethylene glycol, decamethylene. C2-C10 alkylene glycols such as glycols, alicyclic diols such as cyclohexanedimethanol, dialkylene glycols such as diethylene glycol and dipropylene glycol, hydroquinone, resorcin, 2,2-bis (4-hydroxyphenyl) propane, Aromatic ring-containing diols such as 1,4-dihydroxydimethylbenzene, polyalkylene glycols such as polyethylene glycol, polypropylene glycol and polytetramethylene glycol Call (polyalkylene glycol), other bisphenol A / alkylene oxide adduct, and the like hydroquinone / alkylene oxide adducts.

The polyester (b) may contain a small amount of a hydroxycarboxylic acid component such as p-hydroxybenzoic acid and p- (β-hydroxyethoxy) benzoic acid in addition to the above-mentioned dicarboxylic acid component and glycol component.

Further, the polyester (b) may contain, in addition to the above-mentioned dicarboxylic acid component, glycol component and hydroxycarboxylic acid component, a polyfunctional component in a small proportion in a range in which crosslinking does not substantially occur. Examples of the polyfunctional component include trimellitic acid, dimethylolpropionic acid, glycerin, and trimethylolpropane.

The intrinsic viscosity of polyester (b) (measured in an orthochlorophenol solvent at 35 ° C.) is 0.45 to 0.4.
It is preferably 9 dl / g. The glass transition temperature of the polyester (b) is preferably 60 to 130 ° C.

Typical examples of the polyester (b) include the following copolyesters. (Copolymerized Polyester Example 1) Acid component terephthalic acid 70 to 100 mol% isophthalic acid 0 to 30 mol% 5-Na sulfoisophthalic acid (compound of the formula (1)) 11 to 20 mol% glycol component ethylene glycol 50 to 100 Mol% 1,4-butanediol 50-100 mol% (Copolyester Example 2) Acid component 2,6-naphthalenedicarboxylic acid 70-100 mol% Isophthalic acid 0-30 mol% 5-K sulfoisophthalic acid (the above formula (Compound of (2)) 11 to 20 mol% Glycol component Ethylene glycol 50 to 100 mol% Bisphenol A / ethylene oxide adduct 50 to 100 mol%

The layer (A) and the layer (B) constituting the laminated polyester film of the present invention include inorganic particles such as silicon oxide, iron oxide, kaolin, aluminum oxide, aluminum silicate, calcium carbonate and titanium oxide; acrylic resin,
Organic particles such as polystyrene resin, silicone resin, melamine resin and carbon black; antioxidants, lubricants, ultraviolet absorbers, colorants, pigments, antistatic agents and the like can be contained as necessary.

In the laminated polyester film of the present invention, the layer (B) is present on one side or both sides of the layer (A) composed of the polyester (a). The film preferably has a two-layer structure or a three-layer structure. In the case of a three-layer structure,
The central layer is layer (A).

When the thickness of the layer (A) is Ta and the thickness of the layer (B) is Tb, it is preferable that the following formula 0.062 <Tb / Ta <0.15 is satisfied, and Ta is 1. 5-250μ
m and Tb are preferably 0.1 to 10 μm.

Further, the laminated film of the present invention is preferably biaxially oriented.

The laminated polyester film of the present invention having such a constitution is excellent in antistatic performance and adhesiveness and is suitably used for magnetic recording tapes, magnetic recording disks, magnetic card printing materials, graphic materials, photosensitive materials and packaging materials. obtain.

A magnetic recording medium can be easily obtained by providing a magnetic layer on the layer (B) side of the laminated polyester film of the present invention by a method known per se. The adhesiveness between the laminated polyester film and the magnetic layer is excellent, and the antistatic performance of the film is excellent, so that the running durability of the magnetic recording medium is good, and the adhesion of dust and the like is reduced during the process of manufacturing the magnetic recording medium.

The laminated polyester film of the present invention can be produced by a conventionally known method for producing a laminated film. A method in which the polyester (a) forming the layer (A) and the polyester (b) forming the layer (B) are melt coextruded to prepare an unstretched laminated film and the film is biaxially stretched is particularly preferable.

In preparing an unstretched laminated film by melt co-extrusion, polyester (a) and polyester (b) are each melted in a separate extruder and immediately before or in an extrusion die. An unstretched laminated film is obtained by bringing the resin layers into contact and cooling.

As the means for contacting the molten resin, a feed block can be used when the molten resin is contacted immediately before the extrusion die. A stuff plate die or a multi-manifold die can be used when making contact within the die.

As the method for biaxial stretching, a sequential biaxial stretching method and a simultaneous biaxial stretching method can be used, and the former method is preferably used. Furthermore, a three-stage stretching method and a four-stage stretching method can be used.

When biaxially stretched by the sequential biaxial stretching method, the temperature is higher than the glass transition temperature (Tg) of the polyester (a) constituting the layer (A), preferably (Tg + 3) to.
The first stage is stretched at (Tg + 50) ° C., and then the second stage is stretched in the temperature range which is the same as the first stage stretching temperature or higher by 20 ° C. The stretching ratio is at least 2 times in the uniaxial direction, further 2.5 times or more, and the area ratio is 6 times or more,
Furthermore, it is preferable to set it to 8 times or more. The heat treatment (heat setting) is preferably carried out under tension at a temperature of 170 ° C. or higher, more preferably 190 ° C. or higher. The upper limit of the heat treatment temperature depends on the treatment time, but it goes without saying that the film has a stable shape. The heat treatment time is several seconds to several tens of seconds,
Furthermore, 3 seconds to 30 seconds is preferable.

[0045]

EXAMPLES The present invention will be described in more detail with reference to examples. In addition, the part in an Example means a weight part. Each characteristic value was measured by the following method.

(1) Adhesiveness <Magnetic paint> The following evaluation paint was dried on the surface of the polyester film layer (B) with a Meyer bar to a thickness of about 4 μm.
It is applied so that the thickness becomes m and dried at 100 ° C. for 3 minutes. After that, aged at 60 ° C. for 24 hours, and then Scotch tape No. 600 (manufactured by 3M), width 12.7 mm, length 15
cm is adhered so that air bubbles do not enter, and the top is JIS
It is leveled and brought into close contact with a manual load roll described in C2701 (1975), and cut into a tape width. 180 this tape
° Measure the strength when peeled.

[Evaluation paint] Urethane resin Nipporan 2304 (manufactured by Nippon Polyurethane) 25 parts PVC / vinyl acetate resin S-REC A (manufactured by Sekisui Chemical Co., Ltd.) 50 parts Dispersant Resion P (manufactured by Riken Vitamin) 1 part Magnetic Agent CTX-860 (manufactured by Toda Kagaku Co., Ltd.) 500 parts was dissolved in a mixed solvent of methyl ethyl ketone / toluene / cyclohexanone to give a 40% solution, which was then applied with a sand glider to 2
Disperse in time. Thereafter, 25 parts (corresponding to solid content) of Coronate L as a cross-linking agent is added and well stirred to obtain a magnetic coating material.

(2) Charging property After coating, drying, stretching and heat treatment in the film forming step,
The amount of charge is measured by an electrometer at a position 3 cm away from the layer (B) of the film, and evaluation is performed in the following three stages. ◯: 5 KV or less Δ: 5-8 KV ×: 8 KV or more

(3) Heat of Crystal Melting Using a scanning calorimeter (DSC), 0.001 g of a polyester sample was heated at a rate of 12 ° C. per minute (under N ₂ atmosphere) to obtain melting from an endothermic curve. The amount of endotherm is calculated and converted to 1 g of sample weight.

Example 1 Intrinsic viscosity [η] (measured in an orthochlorophenol solvent at 35 ° C.) was 0.64 dl /
g polyethylene terephthalate (polyester a-
1) and terephthalic acid-isophthalic acid-5-Ksulfoisophthalic acid (acid of formula (2) above) -ethylene glycol-neopenpentylene glycol-1,4-butanediol copolymerized polyester (wherein 5-Ksulfo The ratio of isophthalic acid accounts for 17 mol% of all dicarboxylic acids, and the heat of fusion of crystal is 1.2 cal / g) (polyester b-
1) was coextruded from a two-layer die, stretched in the longitudinal direction by 3.4 times and in the transverse direction by 3.7 times, and then heat-treated to obtain a biaxially oriented laminated film having a bilayer structure. The thickness of the layer (A) of this film was 14 μm, and the thickness of the layer (B) was 0.7 μm.
The properties of this laminated film are shown in Table 1.

Comparative Example 1 Polyester (a) of Example 1
From -1), a monolayer biaxially oriented film was produced under the stretching conditions described in Example 1. The characteristics of this film are shown in Table 1.

[Example 2] Intrinsic viscosity [η] was 0.62d
1 / g of polyethylene-2,6-naphthalenedicarboxylate (polyester a-2) and 2,6-naphthalenedicarboxylic acid-terephthalic acid-isophthalic acid-5-N
a Sulfoisophthalic acid (acid of the above formula (1))-ethylene glycol-neopentylene glycol-bisphenol A / ethylene oxide adduct copolymerized polyester (wherein the proportion of 5-Na sulfoisophthalic acid is 19 mol% of the total dicarboxylic acid) And the heat of crystal fusion is 1.5 cal
/ Polyester) (polyester b-2) was coextruded from a two-layer die and bidirectionally stretched in the same manner as in Example 1 to obtain a biaxially oriented laminated film having a two-layer structure. Layer (A) of this film
Had a thickness of 9 μm, and the layer (B) had a thickness of 0.5 μm. The properties of this laminated film are shown in Table 1.

[Example 3] The polyester (b-2) used in Example 2 was coextruded on both sides of the polyester (a-1) used in Example 1 and stretched in the same manner as in Example 1 to obtain three layers. A biaxially oriented laminated film having a structure was obtained. The thickness of this film is 0.6 μm (b-2) / 10 μm (a-1) /0.6.
It was μm (b-2). The characteristics of this film are shown in Table 1.

Example 4 The polyester (b-1) used in Example 1 was coextruded on both sides of the polyester (a-2) used in Example 2 and stretched in the same manner as in Example 1 to obtain three layers. A biaxially oriented laminated film having a structure was obtained. The thickness of this film is 1.2 μm (b-1) / 19 μm (a-2) /1.2
It was μm (b-1). The characteristics of this film are shown in Table 1.

Comparative Example 2 Polyester (a-1) and terephthalic acid-isophthalic acid-ethylene glycol-neopenpentylene glycol-1,4-butanediol-diethylene glycol copolymerized polyester (heat of fusion of crystallization:
1.2 cal / g) (polyester b-3) was coextruded and stretched in the same manner as in Example 1 to obtain a biaxially oriented laminated film having a bilayer structure. The thickness of layer (A) of this film is 14
The thickness of the layer (B) was 0.8 μm. The properties of this laminated film are shown in Table 1.

[Examples 5 to 9] Two to three layers obtained in the same manner as in Example 1 except that the constitution and thickness of the film of each layer in Example 1 were changed as shown in Table 1. The characteristics of the biaxially oriented laminated film are shown in Table 1.

[Table 1]

[0057]

According to the present invention, a laminated polyester film excellent in antistatic performance and adhesiveness and a magnetic recording medium using the same are provided.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical display location C08G 63/685 NNN 63/688 NNK (72) Inventor Masayuki Fukuda 3-37 Oyama, Sagamihara City, Kanagawa Prefecture No. 19 Inside the Sagamihara Research Center, Teijin Limited

Claims (6)

[Claims] 1. A main acid component of at least one of terephthalic acid and naphthalenedicarboxylic acid, and a group —S.
From a polyester (a) having substantially no O ₃ M (where M represents a metal atom, an ammonium group, a quaternary amine or a quaternary phosphonium group in the same amount as —SO ₃ ) in the molecule. On one or both sides of the layer (A)
The dicarboxylic acid component containing O ₃ M (where M is the same as above) comprises 10 to 30 mol% of the dicarboxylic acid component, or / and the group —SO ₃ M (where M is the same as above).
A layer (B) consisting of a polyester (b) having a glycol fusion component containing 10 to 30 mol% of the glycol component and having a heat of crystal fusion of 5 cal / g or less, and a layer (A) and a layer (B). Is a low-charge laminated polyester film which is laminated by co-extrusion. 2. The low-charge laminated polyester film according to claim 1, wherein at least one of terephthalic acid and naphthalenedicarboxylic acid accounts for 70 mol% or more in the acid component of the polyester (a). 3. The low-charge laminated polyester film according to claim 1, wherein the polyester film (b) has a glass transition point of 60 to 130 ° C. 4. The low-charge laminated polyester film according to claim 1, wherein the polyester (a) is polyethylene terephthalate or polyethylene-2,6-naphthalene dicarboxylate. 5. The thickness Ta of the layer (A) and the thickness T of the layer (B).
The low-charge laminated polyester film according to any one of claims 1 to 4, wherein b and the following formula 0.002 <Tb / Ta <0.15 are satisfied. 6. A magnetic recording medium having a magnetic layer provided on at least one surface of the low-charge laminated polyester film according to claim 1. Description: