JPH06328644A - Easily adhesive laminated film - Google Patents

Abstract

PURPOSE:To improve adhesive strength and to enhance antistatic properties by laminating a B layer made of a polyester having a specific value and an antistatic substance having a sulfonic acid base in a molecule on one surface of a polyester A layer made of a specific dicarboxylic acid and a dihydroxy compound and having a specific value and biaxially orienting it. CONSTITUTION:A polyester A layer is formed of a dicarboxylic acid ingredient containing 70mol% or more of terephthalic acid and/or naphthalenedicarboxylic acid and a dihydroxy compound ingredient. This polyester has a secondary transition point of 60-200 deg.C. A B layer is formed of a polyester having a crystal melting heat of 5cal/g or more and an antistatic substance having a sulfonic acid base in a molecule. The substance is previously melted and mixed with the polyester or mixed to be supplied at the time of co-extruding. An unoriented film obtained by laminating the B layer on one surface of the polyester A layer by co-extrusion is biaxially oriented to obtain a laminated oriented film.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated film, and more specifically, it has excellent antistatic property and adhesive property and is useful as an antistatic adhesive property for magnetic recording media, packaging materials, display materials, graphic materials, laminated materials and the like. It relates to a polyester laminated film.

[0002]

2. Description of the Related Art Polyester films, particularly polyethylene terephthalate and polyethylene-2,6-naphthalene dicarboxylate films, are used for magnetic tapes, floppy disks, magnetic cards, graphic materials, packaging materials, etc. Since it is crystallized, its adhesive strength is low, and it is easily charged, so that many restrictions are practically imposed.

In order to overcome these weak points, formation of a primer layer with a water-based or solvent-based coating agent, extrusion laminating, hot melt coating and the like are known. For example, in the case of a coating agent, the binder resin needs to be dissolved or dispersed in the medium, which limits the selection of the resin. In addition, there are cases where the thickness of the coating layer cannot be made sufficiently thick from the viewpoint of coatability. From these points, it was difficult to design the surface to sufficiently enhance the adhesiveness and antistatic property of the film. Moreover, since the medium is volatilized during coating, it has a drawback of contaminating the working environment.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a polyester laminated film which is excellent in antistatic property and adhesiveness and which is useful for magnetic media, packaging materials, laminated materials and the like.

[0005]

The present invention has the following constitution in order to achieve this object.

The heat of crystal fusion is 5 cal on at least one side of the polyester layer (A layer) having a second-order transition point of 60 to 200 ° C. and made from a dicarboxylic acid containing 70 mol% or more of terephthalic acid and / or naphthalenedicarboxylic acid and a dihydroxy compound. / G or less polyester and a layer (B layer) comprising an antistatic substance having a sulfonate group in the molecule,
For example, it is a multilayer film which is not stretched by coextrusion and is further biaxially stretched, which is an easily antistatic adhesive laminated film.

The easily antistatic adhesive laminate film of the present invention comprises a magnetic layer coated on the surface of the B layer having excellent adhesiveness, and an ink receiving layer is similarly formed to form a magnetic recording medium or a package. Can be used as a material.

The present invention will be described.

Since the laminated film of the present invention further uses a polyester having a low crystallinity, it is possible to form a surface exhibiting a high adhesive force with respect to magnetic paints, inks and the like. Further, since it contains an antistatic agent having a sulfonate group, it has high antistatic properties.

In the present invention, the thickness of the layer to be laminated can be freely changed to make it thicker in some cases, so that the adhesive force to ink or magnetic paint can be improved and the antistatic property can be enhanced.

Further, when coextrusion is adopted, the adhesiveness between the layers of the laminated film is high.

The dicarboxylic acid of the A layer polyester of the present invention contains 70 mol% of at least one dicarboxylic acid selected from terephthalic acid and 2,6-naphthalenedicarboxylic acid.
It comprises a dicarboxylic acid containing. Less than 30 mol% may use other dicarboxylic acids. Examples of the other dicarboxylic acid include isophthalic acid, phthalic acid, adipic acid and sebacic acid.

Examples of the dihydroxy compound include ethylene glycol, 1,4-butanediol, 1,3-propanediol, 1,6-hexanediol, neopentyl glycol, diethylene glycol, 1,6-cyclohexanedimethanol and p-xylylene. Examples thereof include glycol and polyethylene glycol.

As examples of polyesters, polyethylene terephthalate and polyethylene-2,6-naphthalene dicarboxylate are particularly preferred. Other examples include terephthalic acid-2,6-naphthalenedicarboxylic acid-ethylene glycol copolymer, terephthalic acid-2,6-naphthalenedicarboxylic acid-1,4-butanediol-ethylene glycol copolymer, polybutylene-2. 6-naphthalene dicarboxylate and the like.

The ratio of the two dicarboxylic acids is 70 mo.
If it is less than 1%, the film base has poor rigidity, and the performance is practically insufficient.

This polyester has a second-order transition point of 60 to 200 ° C. If it is less than 60 ° C, the heat resistance of the film is poor, and if it exceeds 200 ° C, the moldability is poor.

The B layer polyester of the present invention is made from a dicarboxylic acid and a dihydroxy compound.

As the polybasic acid, terephthalic acid, isophthalic acid, phthalic acid, phthalic anhydride, 2,6-naphthalenedicarboxylic acid, 4,4'-diphenyldicarboxylic acid,
Examples thereof include 1,4-cyclohexanedicarboxylic acid, adipic acid, sebacic acid, trimellitic acid, pyromellitic acid and dimer acid. Two or more of these components can be used. Further, a small proportion of an unsaturated polybasic acid such as maleic acid, fumaric acid or itaconic acid or a hydroxycarboxylic acid such as p-hydroxybenzoic acid or p- (β-hydroxyethoxy) benzoic acid may be used together with these components. it can. The ratio of the unsaturated polybasic acid component and the hydroxycarboxylic acid component is at most 10 mol%, preferably 5 mol% or less.

As the ester-forming derivative of polybasic acid, lower alkyl ester, especially methyl ester can be exemplified as preferable one. Examples of the dihydroxy compound used for reacting with the dicarboxylic acid include ethylene glycol, 1,4-butanediol, neopentyl glycol, diethylene glycol, dipropylene glycol, 1,6-hexanediol, 1,4-cyclohexanedimethanol and xylylene. Examples thereof include glycol, dimethylolpropionic acid, glycerin, trimethylolpropane, poly (ethylene oxide) glycol, poly (tetramethylene oxide) glycol, and bisphenol A alkylene oxide adduct. These can use 2 or more types. The heat of crystal fusion of this polyester is 5 cal / g or less. 5c
If it exceeds al / g, the adhesiveness tends to be poor.

Examples of the polyester component of layer B include terephthalic acid-isophthalic acid-ethylene glycol-1,
4-butanediol type, terephthalic acid-neopentyl glycol-bisphenol A / propylene oxide adduct type, 2,6-naphthalene dicarboxylic acid-isophthalic acid-diethylene glycol-cyclohexane-1,4-dimethanol type copolyester, etc. Can be mentioned.

The softening point, glass transition point and melting point of these copolyesters can be adjusted according to the film forming process conditions.

Examples of the antistatic substance used with polyester, which has a sulfonate group in the molecule, include alkylbenzene sulfonate alkali metal salts, alkane sulfonate alkali metal salts, polyoxyalkylene sulfonate alkali metal salts, Examples thereof include alkyl diphenyl ether disulfonic acid alkali metal salts, copolymers of methallyl sulfonic acid alkali metal salts and acrylic monomers, styrene sulfonic acid alkali metal salt copolymers, vinyl sulfonic acid alkali metal salt copolymers, and the like.

The amount of the antistatic substance blended is polyester 1
0.5 to 40 parts by weight is preferable with respect to 00 parts by weight. The polyester may be melt mixed in advance, or may be mixed and fed at the time of coextrusion.

In producing the laminated film, inorganic particles such as silicon oxide, iron oxide, kaolin, aluminum oxide, aluminum silicate, calcium carbonate and titanium oxide, acrylic resin, polystyrene resin, etc. are contained in the polyester A layer and B layer. Organic particles such as silicone resin, melamine resin, carbon black, etc., antioxidants, lubricants, ultraviolet absorbers, colorants, pigments and the like may be added as required.

The unstretched film with the coextruded A and B layers can be biaxially stretched into a laminated stretched film.

The thickness of the layer A of the stretched film is 1.5 to 25.
The thickness of the layer B is 0 μm, and the thickness of the layer B is preferably 0.1 to 10 μm.

The laminated film thus obtained is antistatic,
It has excellent adhesiveness and is useful for magnetic tapes, magnetic disks, magnetic cards, printing materials, graphic materials, photosensitive materials, packaging materials and the like.

[0028]

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. Moreover, each characteristic value is measured by the following methods.

1) Adhesiveness [Magnetic paint] The evaluation paint is applied to the B layer surface of the sample polyester film by a Meyer bar so that the thickness after drying is about 4 µm, and dried at 100 ° C for 3 minutes. After that, aging was performed at 60 ° C. for 24 hours, and then Scotch tape No. 600 (3M) width 12.7mm, length 15c
Adhere m to prevent air bubbles from entering, and then use JISC2
701 (1975), using a manual load roll to level the film and bring it into close contact, and cut into a tape width. The strength when peeled at 180 ° is measured.

[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) is dissolved in a mixed solvent of methyl ethyl ketone / toluene / cyclohexanone to give a 40% solution, which is dispersed for 2 hours by a sand grinder. 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) Surface specific resistance Using a specific resistance measuring device manufactured by Takeda Riken Co., Ltd., 23 ° C., 6
The surface specific resistance value (Ω / □) is measured after 1 minute at an applied voltage of 500 V under the condition of 5% RH.

3) Heat of fusion of crystals Using a scanning calorimeter, a sample of polyester 0.001
The g and heating rate per minute 12 ° C. (N ₂ atmosphere), sample weight 1g obtains the endothermic energy due to melting of the endothermic curve
Convert to per hit.

[0033]

[Example 1] Intrinsic viscosity [η] is 0.60, second-order transition point 7
100 parts by weight of polyethylene terephthalate (A-1) and terephthalic acid-isophthalic acid-ethylene glycol-bisphenol A-ethylene oxide adduct copolymerized polyester (heat of crystal fusion 1.5 cal / g) and lithium dodecylbenzenesulfonate 3 parts by weight at 1 ° C 2. The composition (B-1) consisting of 3 parts was coextruded from a two-layer die to obtain a composition in the machine direction 3.
After stretching 5 times and 3.6 times in the transverse direction, it was further heat treated to obtain a laminated film. The first layer (A) and the second layer (B) of this stretched film had a thickness of 12 μm and 0.8 μm, respectively. The properties of this laminated film are shown in Table 1.

[0034]

[Comparative Example 1] Table 1 shows the properties of a stretched film obtained in the same manner as in Example 1 from the first layer (A) using (A-1).

[0035]

Example 2 0.15 wt% of silicon oxide (average particle size 0.03 μm) was added to the composition (B-1) of Example 1, and both surfaces of the polyester (A-1) layer were coated with a three-layer die. It was extruded and similarly stretched to obtain a three-layer laminated film. Layer B (0.
A film having a constitution of 5 μm) / A layer (11 μm) / B layer (0.5 μm) was obtained. The characteristics are shown in Table 1.

[0036]

[Example 3] Intrinsic viscosity [η] is 0.65, second-order transition point 1
12 ° C polyethylene-2,6-naphthalenedicarboxylate (A-2) and 2,6-naphthalenedicarboxylic acid-isophthalic acid-1,4-butanediol, hydrogenated bisphenol A / propylene oxide adduct copolymerized polyester ( A composition (B-2) consisting of 100 parts by weight of heat of fusion of crystal 0.9 cal / g) and 2.5 parts by weight of sodium decanesulfonate was co-extruded from a two-layer die to obtain 3.6 in the longitudinal direction.
After stretching twice and 3.5 times in the transverse direction, heat treatment was performed to obtain a laminated film. The thickness of the first layer (A-2) of the film is 15μ
m, and the thickness of the second layer (B-2) was 1.3 μm. The properties of this laminated film are shown in Table 1.

[0037]

[Embodiment 4] Intrinsic viscosity [η] is 0.65 and second-order transition point is 7.
0 ° C. polyethylene terephthalate (containing aluminum oxide with a particle size of 0.1 μm) (A-3) and terephthalic acid
Copolymerized polyester (particle size: 0. 1) consisting of ethylene glycol-1,4-butanediol-bisphenol A / ethylene oxide adduct and having a heat of crystal fusion of 0.7 cal / g
2. A composition (B-3) consisting of 100 parts by weight of silica (05 μm silica) and 8 parts by weight of sodium methanesulfonate-ethyl acrylate-ethyl methacrylate copolymer (B-3) was coextruded through a two-layer die, and the composition was melted in the longitudinal direction. After stretching 5 times and 3.6 times in the transverse direction, heat treatment was performed to obtain a laminated film. The thickness of the first layer (A-3) of this stretched film is 14 μm, and the thickness of the second layer (B-3) is
The thickness of -3) was 1.5 μm. The properties of this laminated film are shown in Table 1.

[0038]

[Example 5] Intrinsic viscosity [η] is 0.62, second-order transition point 1
12 ° C polyethylene-2,6-naphthalenedicarboxylate (containing 0.2 μm particle diameter silica and 0.1 μm particle diameter alumina) (A-4) and 2,6-naphthalenedicarboxylic acid-terephthalic acid-ethylene glycol -1,4
-Butanediol-Bisphenol A / ethylene oxide adduct, copolymerized polyester having a heat of fusion of crystal of 0.9 cal / g (containing kaolin having a particle size of 0.2 μm) 10
A composition (B-4) consisting of 0 part by weight and 2 parts by weight of potassium dodecylbenzenesulfonate was co-extruded from a two-layer die, stretched 3.5 times in the longitudinal direction and 3.4 times in the transverse direction, and then heat treated. To obtain a laminated film. The stretched film had a thickness of the first layer (A-4) of 8 μm and a thickness of the second layer (B-4) of 0.5 μm. The properties of this laminated film are shown in Table 1.

[0039]

Examples 6 to 8 Polyester (B-
Table 1 shows the properties of the film obtained in the same manner as in (1) except that the thickness of the second layer (B) was changed.

[0040]

[Examples 9 to 11] The second outer layer (B) in Example 2
Table 1 shows the characteristics of the film obtained in the same manner except that the thickness was changed.

[0041]

Examples 12 to 13 Table 1 shows the characteristics of the films obtained in the same manner as in Example 4 except that the thickness of the second layer (B) using the polyester (B-3) was changed.

The surface of layer B of these films is UV.
The adhesion to ink was high.

[0043]

[Table 1]

Claims (3)

[Claims] 1. A second transition point formed from a dicarboxylic acid containing 70 mol% or more of terephthalic acid and / or naphthalenedicarboxylic acid and a dihydroxy compound has a second transition point of 60 to 200 ° C.
The heat of crystal fusion is 5 on at least one side of the polyester A layer of
An easily antistatic adhesive laminate film in which a B layer comprising a polyester having a cal / g or less and an antistatic substance having a sulfonate group in the molecule is laminated and biaxially oriented. 2. A magnetic recording medium having a magnetic layer provided on at least one surface of the laminated antistatic adhesive film according to claim 1. 3. A laminated film obtained by providing an ink layer on at least one surface of the easily antistatic adhesive laminated film according to claim 1.