JPH06238746A - Production of easy adhesive laminated film - Google Patents

Abstract

PURPOSE:To produce a polyester laminated film excellent in heat-resistance, adhesiveness and mechanical characteristics and useful as a magnetic recording medium, a packing material and a laminating material. CONSTITUTION:A layer (B) of polyester with the crystal heat of fusion of 7cal/g or less and a secondary transition point of 30-180 deg.C is laminated to at least the single surface of a layer (A) of polyester consisting of a dicarboxylic acid component containing 70mol% or more of terephthalic acid and/or 2,6- naphthalenedicarboxylic acid and a dihydroxy compd. component by co-extrusion to obtain a laminated non-stretched film which is, in turn, stretched in a biaxial direction. This stretched film is re-stretched at least in a monoaxial direction at 80-220 deg.C to produce an easy adhesive laminated film.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an easily-adhesive laminated film, more specifically, an easily-adhesive laminated film which is excellent in heat-resistant adhesiveness and mechanical properties and is useful as a magnetic recording medium, a packaging material, a laminating material and the like. The present invention relates to a method of manufacturing a film.

[0002]

2. Description of the Related Art Polyester film, especially polyethylene terephthalate film, polyethylene-2,6-naphthalene dicarboxylate film, is a magnetic tape,
Floppy disk, magnetic card, graphic material,
Although it is used as a packaging material, it has a drawback that the film is highly oriented and crystallized and thus has a low adhesive force with a layer formed thereon.

Conventionally, this drawback is that the surface of the polyester film is coated with a layer of an easily adhesive resin and coextruded,
Although this has been overcome by laminating with a laminate or the like, this resin usually has low heat resistance, and various restrictions have been added to film forming conditions and processing conditions of the film. For example, in order to increase the strength of the polyester film, it is often stretched in three stages or four stages. However, when an easily adhesive layer is formed in this step, the layer has low heat resistance and may be heat-adhered to a roll during the process. Many. On the other hand, when a polymer having stronger crystallinity is used for the purpose of improving the heat resistance of the easy-adhesion layer, the adhesive force tends to decrease. Further, in many cases, lubricant fine particles are contained in the surface layer for the purpose of imparting runnability to the film, but in this case, when the thickness of the layer becomes thin, the adhesion force of the fine particles decreases.

Therefore, there is a demand for an easily adhesive resin which is excellent in both heat resistance and adhesive strength. Particularly in the case of lamination by the coextrusion method, the resin is preferably a polyester resin, but a resin having the above characteristics has not been obtained.

[0005]

DISCLOSURE OF THE INVENTION The present inventors have found a polyester resin having both excellent heat resistance and adhesive strength, and by laminating it on a polyester film,
The present invention has been achieved as a result of intensive research to produce a film having excellent mechanical properties.

Accordingly, an object of the present invention is to provide a method for producing an easily adhering polyester laminated film which is excellent in heat resistance and mechanical properties.

Another object of the present invention is to provide a method for producing an easily-adhesive polyester laminated film which is excellent in heat-resistant adhesiveness, mechanical properties and slipperiness and is useful for magnetic recording media, packaging materials, laminated materials and the like. It is in.

[0008]

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

A polyester layer (A) made of a dicarboxylic acid component containing 70 mol% or more of terephthalic acid and / or 2,6-naphthalenedicarboxylic acid and a dihydroxy compound component has a crystal fusion heat of 7 cal on at least one surface thereof.
/ G or less, the layer-unstretched film obtained by laminating the layer (B) of polyester having a secondary transition point of 30 to 180 ° C by coextrusion is biaxially stretched, and then 80 to 220 ° C.
A method for producing an easily-adhesive laminated film, which comprises re-stretching at least uniaxially at the temperature of.

In the present invention, the polyester of the layer A is a crystalline polyester prepared from a dicarboxylic acid component and a dihydroxy compound component containing terephthalic acid and / or 2,6-naphthalenedicarboxylic acid in an amount of 70 mol% or more, preferably 80 mol% or more. . This polyester is a polymer having a heat of fusion of crystallization of more than 7 cal / g. Thirty
Examples of the dicarboxylic acid component that can be used in a proportion of less than mol% include isophthalic acid, phthalic acid, adipic acid, sebacic acid and the like. As the dihydroxy compound component, ethylene glycol, 1,4-butanediol, 1,3-propanediol, 1,6-hexanediol, neopentyl glycol, diethylene glycol, 1,6-cyclohexanedimethanol, p-xylylene glycol, Examples thereof include polyethylene glycol.

Specific examples of polyesters include polyethylene terephthalate, polyethylene-2,6-naphthalene dicarboxylate, and polytetramethylene-2,6-.
Naphthalene dicarboxylate, terephthalic acid-2,6
-Naphthalenedicarboxylic acid-ethylene glycol copolymer, terephthalic acid-2,6-naphthalenedicarboxylic acid-
Preferred examples include 1,4-butanediol-ethylene glycol copolymer and the like. Among these, polyethylene terephthalate and polyethylene-2,6-naphthalene dicarboxylate are particularly preferable.

When the proportion of the above-mentioned two kinds of dicarboxylic acids, that is, terephthalic acid and / or 2,6-naphthalenedicarboxylic acid, is less than 70 mol%, it is not preferable because the film base has a poor rigidity and practically lacks in performance.

In the present invention, the polyester of the layer B has a heat of crystal fusion of 7 cal / g or less, preferably 5 cal / g.
It is a polyester having a g or less and a second-order transition point of 30 to 180 ° C, preferably 40 to 150 ° C. If the heat of fusion of crystals exceeds 7 cal / g, the crystallinity increases and the adhesiveness decreases. If the second-order transition point is lower than 30 ° C., heat resistance is insufficient, causing a problem of sticking to a roll in the process. On the other hand, if it exceeds 180 ° C., the stretching property is poor.
It is difficult to form a uniform layer.

As the acid component of the polyester constituting the layer B, terephthalic acid, isophthalic acid, phthalic acid, phthalic anhydride, 2,6-naphthalenedicarboxylic acid, 4,4'-
Biphenyldicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, adipic acid, sebacic acid, trimellitic acid,
Pyromellitic acid, dimer acid, etc. can be illustrated. 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 dihydroxy compound component, ethylene glycol, 1,4-butanediol, neopentyl glycol, diethylene glycol, dipropylene glycol,
1,6-hexanediol, 1,4-cyclohexanedimethanol, xylylene glycol, poly (ethylene oxide) glycol, poly (tetramethylene oxide)
Examples thereof include glycol and the like. These can use 2 or more types. Furthermore, a small proportion of a trifunctional or higher polyhydroxy compound component such as dimethylolpropionic acid, glycerin, or trimethylolpropane can be used together with these components.

Specific examples of the polyester constituting the layer B include terephthalic acid-isophthalic acid-ethylene glycol copolymer, terephthalic acid-isophthalic acid-1,4-butanediol copolymer, 2,6-naphthalenedicarboxylic acid. -Isophthalic acid-1,4-butanediol-neopentyl glycol copolymer, terephthalic acid-2,6-naphthalenedicarboxylic acid-1,4-butanediol-diethylene glycol copolymer, terephthalic acid-isophthalic acid-ethylene glycol- Examples thereof include polyethylene glycol-bisphenol A / ethylene oxide adduct copolymers. These copolyesters are 7c
Although it has a heat of fusion of crystal of al / g or less and a second-order transition point of 30 to 180 ° C., these characteristics, softening point, melting point and the like can be adjusted according to the film forming process conditions.

Polyester A and B in the present invention
The polyester of the layer can be produced by a known method. For example, polyethylene terephthalate is produced by esterification reaction of terephthalic acid and ethylene glycol, or transesterification of an ester-forming derivative of terephthalic acid (lower alkyl ester, especially dimethyl ester) with ethylene glycol to form a monomer. Then, the polyester can be produced by polymerizing the monomer. In addition, terephthalic acid (82 mol%) and isophthalic acid (18 mo
1%) with ethylene glycol (80 mol%) and neopentyl glycol (20 mol%) through an esterification reaction, or dimethyl terephthalate (82 mol).
%) And dimethyl isophthalate (18 mol%) and ethylene glycol (80 mol%) and neopentyl glycol (20 mol%) are transesterified to prepare a monomer, and then the monomer is polymerized to produce a polyester. can do. The use of catalysts in these reactions is preferred.

The polyester of A layer and the polyester of B layer each have a number average molecular weight of 5,000 to 40,000.
Is preferred.

In the present invention, the polyester of the A layer and the polyester of the B layer are melt-coextruded to form a laminated unstretched film in which the B layer is laminated on at least one side of the A layer, and the laminated unstretched film is biaxially stretched. It is necessary to stretch in the machine direction and then restretch at a temperature of 80 to 220 ° C. in a few uniaxial directions, that is, in the machine direction and / or the transverse direction.

The coextrusion can be carried out by a conventionally known method, in which case the polyester and / or
Alternatively, the polyester of the layer B may be formed by adding inorganic particles such as silicon oxide, iron oxide, kaolin, aluminum oxide, aluminum silicate, calcium carbonate and titanium oxide, a crosslinked acrylic resin,
If necessary, organic particles such as crosslinked polystyrene resin, crosslinked silicone resin, melamine resin, carbon black, etc., antioxidants, ultraviolet absorbers, colorants, pigments, antistatic agents, etc. can be contained. The structure of the coextrusion die and the extrusion temperature can be arbitrarily selected.

Stretching of the laminated unstretched film can be carried out according to conventionally known methods and conditions, but the stretching ratio is preferably 6 to 10 times in area ratio. A sequential biaxial stretching method is preferable as the stretching method.

The re-stretching of the biaxially stretched film is 80 to 220.
The stretching is carried out at least uniaxially at a temperature of ° C, but the stretching ratio is preferably such that the final area ratio is 12 to 22 times.
If the re-stretching temperature is lower than 80 ° C, stretching is not performed uniformly, while if it is higher than 220 ° C, crystallization is excessively promoted or breakage easily occurs, which is not preferable. During this re-stretching, the film is heated, but avoids sticking of the film surface to the roll during contact with the roll during the process. Further, the multi-stage drawing has the advantage that the Young's modulus of the film can be further increased and the unevenness of the film thickness can be reduced. Heating to a temperature of 80 to 220 ° C. may be either direct (contact) heating or indirect (non-contact) heating. It is preferable to appropriately select the stretching temperature depending on the combination of the A layer and the B layer.

In the laminated film obtained by the present invention, the thickness of the A layer can be arbitrarily selected, but it is preferably 2 to 250 μm, and the thickness of the B layer is 0.1 to 20 μm.
And is preferably 15% or less of the thickness of the A layer.
This is to avoid a decrease in Young's modulus of the laminated film. The Young's modulus of the laminated film is preferably 600 kg / mm ² or more.

The laminated film obtained by the present invention is
It has excellent heat-resistant adhesiveness and slipperiness, and is useful for magnetic tapes, magnetic disks, magnetic cards, printing materials, graphic materials, photosensitive materials, packaging materials and the like.

[0024]

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

1. Adhesiveness <Magnetic paint> The evaluation paint is applied to the (B) layer surface of the sample film with a Meyer bar so that the thickness after drying is about 4 µm, and dried at 100 ° C for 3 minutes. After this, 2 at 60 ℃
Aged for time, then Scotch tape No.600
Adhesion (made by 3M) having a width of 12.7 mm and a length of 15 cm so that air bubbles do not enter.
975) described above, it is leveled and brought into close contact with a manual load roll, and cut into a tape width. The strength when peeled at 180 ° is measured.

[Evaluation paint] In terms of solid content, 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) 500 parts

[0027] is dissolved in a mixed solvent of methyl ethyl ketone / toluene / cyclohexanone to obtain a 40% solution, which is dispersed for 2 hours by a sand grinder. After that, 25 parts (corresponding to solid content) of the cross-linking agent Coronate L is added and well stirred to obtain a magnetic coating material.

2. Average molecular weight of polyester The polymer is dissolved in orthochlorophenol or tetrahydrofuran and measured by GPC (gel permeation chromatograph) method.

3. Polyester Crystal Melting Heat Using a scanning calorimeter (DSC), 0.001 g of a polyester sample was heated at a rate of 12 ° C./min (under N ₂ atmosphere) to obtain the endothermic energy by melting from the endothermic curve. Converted per 1 g of sample weight.

4. Second-order transition point of polyester It is measured at a temperature rising rate of 20 ° C./min using DSC.

[0031]

Example 1 Polyethylene terephthalate (A-1) having an average molecular weight of 23,000 and terephthalic acid (82 mol)
%)-Isophthalic acid (18 mol%)-ethylene glycol (80 mol%)-neopentyl glycol (20
mol%) Copolyester (average molecular weight = 19,0)
00, heat of fusion of crystal 2.1 cal / g, second-order transition point 51
(C-1) (B-1) together with a two-layer die and rapidly cooled to obtain an unstretched film.
2 times, 3.1 times in the transverse direction, 2.1 times in the longitudinal direction at 122 ° C., and further heat treated to obtain a laminated film. The first layer (A) and the second layer (B) of this three-stage stretched laminated film had a thickness of 10 μm and 1 μm, respectively.

The characteristics of this laminated film are shown in Table 1.

[0033]

COMPARATIVE EXAMPLE 1 A single-layer film consisting of only the first layer (A) using (A-1) in Example 1 was extruded, and thereafter, the same operation was carried out to obtain a three-layer stretched single-layer film. The characteristics of this film are shown in Table 1.

[0034]

Example 2 The copolymerized polyester (B
-1) silicon oxide (average particle size 0.08 μm) 0.1w
t% was added, and both sides of the polyester (A-1) layer were coextruded from a three-layer die, and thereafter stretched in the same manner to obtain a three-layer laminated film. This film has a B layer (1 μm) / A layer (20
μm) / B layer (1 μm). The characteristics of this film are shown in Table 1.

[0035]

Example 3 Polyethylene having an average molecular weight of 21,000
2,6-naphthalenedicarboxylate (A-2) and 2,6-naphthalenedicarboxylic acid (20 mol%)-isophthalic acid (40 mol%)-terephthalic acid (40mo)
1%)-ethylene glycol (50 mol%)-bisphenol A / ethylene oxide adduct (20 mol%)
—Neopentyl glycol (30 mol%) copolyester (B-2) (average molecular weight 21,000, heat of fusion of crystal 0 cal / g, second-order transition point 35 ° C.) was coextruded in the same manner as in Example 1, and further The film is stretched 2.6 times in the machine direction and 3 times in the transverse direction, then 2.1 times in the machine direction at 181 ° C., 1.2 times in the transverse direction, and heat treated to form a two-layer four-stage stretch laminated film. Got This film has A layer (10μ
m) / B layer (0.4 μm) /. The characteristics of this laminated film are shown in Table 1.

[0036]

Example 4 Polyethylene terephthalate having an average molecular weight of 23,000 (containing calcium carbonate having an average particle size of 0.1 μm) (A-3), terephthalic acid-isophthalic acid-ethylene glycol-1,4-butanediol-bisphenol A・ Propylene oxide adduct copolymer polyester (number average molecular weight 26,000, heat of fusion of crystal 0.8 cal
1 / g, secondary transition point 42 ° C., silica having average particle diameter of 0.05 μm) (B-3) is co-extruded from a two-layer die and rapidly cooled to obtain an unstretched film, and the unstretched film is lengthwise 2. 6
2 times, 3.1 times in the transverse direction, 2 times in the longitudinal direction and 1.2 times in the transverse direction at 126 ° C., and heat treated to obtain a laminated film. The thickness of the first layer (A-3) and the thickness of the second layer (B-3) of this 4-stage stretched film (A-3) were 10 μm and 0.5 μm, respectively. The properties of this laminated film are shown in Table 4.

[0037]

Example 5 Polyethylene having an average molecular weight of 21,000
2,6-Naphthalenedicarboxylate (average particle size of 0.
(Contains 1 μm silica and alumina with an average particle size of 0.2 μm)
(A-4) and 2,6-naphthalenedicarboxylic acid-terephthalic acid-ethylene glycol-1,4-butanediol-bisphenol A / ethylene oxide adduct copolymerized polyester (number average molecular weight 27,500, heat of fusion of crystal 2. 3cal / g, secondary transition point 69 ° C, average particle size 0.2
A kaolin-containing (B-4) of μm was coextruded from a two-layer die and rapidly cooled to obtain an unstretched film, which was stretched 2.4 times in the machine direction and 3 times in the cross direction, and then stretched at 186 ° C. And then heat-treated to obtain a laminated film. The thickness of the first layer (A-4) of this three-stage stretched film is 8 μm,
The thickness of the second layer (B-4) was 0.4 μm. The characteristics of this laminated film are shown in Table 1.

[0038]

Examples 6 to 8 Laminated films were obtained in the same manner as in Example 1 except that the thickness of layer B was changed as shown in Table 1. The characteristics of this laminated film are shown in Table 1.

[0039]

[Examples 9 to 11] Outer two layers (B) in Example 2
A laminated film was obtained in the same manner except that the thickness was changed as shown in Table 1. The characteristics of this laminated film are shown in Table 1.
Shown in.

[0040]

Examples 12 to 13 Laminated films were obtained in the same manner as in Example 3, except that the thickness of the second layer (B) was changed to that shown in Table 1. The characteristics of this laminated film are shown in Table 1.

[0041]

[Table 1]

[0042]

According to the present invention, it is possible to provide a method for producing a polyester laminated film which is excellent in heat-resistant adhesiveness, mechanical properties and slipperiness.

Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display area B29L 9:00 4F

Claims (1)

[Claims] 1. A heat of crystal fusion of 7 ca on at least one side of a layer (A) of a polyester made of a dicarboxylic acid component containing 70 mol% or more of terephthalic acid and / or 2,6-naphthalenedicarboxylic acid and a dihydroxy compound component.
A laminated unstretched film obtained by laminating a layer (B) of polyester having a secondary transition point of 30 to 180 ° C. at 1 / g or less by coextrusion is biaxially stretched, and then 80 to 220.
A method for producing an easily-adhesive laminated film, which comprises re-stretching at least uniaxially at a temperature of ° C.