JPH07227947A - Easy adhesive polyester film - Google Patents

Abstract

PURPOSE:To provide an easy adhesive polyester film excellent in heat resistance and adhesiveness and showing low charging properties. CONSTITUTION:An easy adhesive polyester film is obtained by applying an easy adhesive layer consisting of a polyester resin (A) having 0.01-30mol% (per total carboxylic acid components) of a carboxylic acid group and/or a base thereof in its mol. chain and an ethylene oxide/propylene oxide copolymer (B) on at least the single surface of a polyester film.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an easily-adhesive polyester film, and more particularly to an easily-adhesive polyester film having excellent heat resistance, high adhesive strength and low electrostatic property.

[0002]

2. Description of the Related Art Polyester films have excellent physical properties and chemical properties and are used for various purposes. However, the polyester film has a drawback that it is inferior in adhesiveness, and a pretreatment for imparting easy adhesiveness is required depending on the application.

As a means for imparting easy-adhesion to a polyester film, an easy-adhesion layer (primer layer) has heretofore been applied by coating an aqueous liquid of an easy-adhesion polyester resin, for example, an aqueous dispersion.
It has been proposed and put to practical use to provide a. For example, it is known to apply an aqueous solution of a hydrophilic polyester resin in which 0.5 mol% or more of a sulfonate group is introduced into a polymer molecule. However, this hydrophilic polyester resin has a drawback that it has a low second-order transition point (Tg) and is poor in wet heat resistance. Further, a surfactant is often added to stabilize the aqueous liquid, but this surfactant also has a problem that the heat resistance is lowered.

It is effective to introduce a rigid component in order to raise the second-order transition point (Tg) of the polyester resin, but in this case, the adhesive property tends to be deteriorated and the hydrophilicity is also lowered, for example. Solubility is low and there is a limit. In addition, when a large amount of sulfonate group is present in the polyester molecule, the charging property is strong, which causes troubles.

Japanese Patent Laid-Open No. 63-115747 discloses that
(A) a water-insoluble polyester copolymer formed from a glycol component and a mixed dicarboxylic acid component containing 0.5 to 15 mol% of a sulfonic acid metal group-containing dicarboxylic acid with respect to the total dicarboxylic acid component; formula

[0006]

[Chemical 1]

(However, n and m are integers of 6 to 1200, R
₁ and R ₂ are an alkylene group or an arylene group having 1 to 4 carbon atoms, R ₁ + R ₂ , and either one of R ₁ and R ₂ is an alkylene group having 3 or more carbon atoms or an arylene group). Disclosed is a thermoplastic resin film laminate having a transparent and excellent antistatic property, which is characterized in that a layer containing a mixture of copolymers is laminated on at least one side. However, the antistatic property of this film laminate cannot be said to be sufficient, and the addition of a low HLB surfactant tends to deteriorate the adhesive properties.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide an easily-adhesive polyester film which has excellent adhesiveness, heat resistance and low electrification property.

[0009]

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

On at least one side of the polyester film,
(A) a carboxylic acid group and / or its base in the molecular chain of 0.
An easily-adhesive polyester film formed by coating an easily-adhesive layer using a polyester resin having 01 to 30 mol% (based on all carboxylic acid components) and (B) an ethylene oxide-propylene oxide copolymer.

The polyester constituting the polyester film in the present invention is a crystalline aromatic polyester, and the acid component thereof is, for example, terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, 4,4'-diphenyldicarboxylic acid. Examples of the glycol component include ethylene glycol, 1,4-butanediol, 1,4-cyclohexanedimethanol, 1,6-hexanediol and the like. Among these,
Polyethylene terephthalate, polyethylene-2,6-
Naphthalene dicarboxylate is preferred. As the aromatic polyester, of course, a homopolymer,
Copolymers of the above components can also be used.

The aromatic polyester may optionally contain, as a lubricant, fine particles of kaolin, calcium carbonate, silica, aluminum oxide, crosslinked silicone resin, crosslinked polystyrene, crosslinked acrylic resin or the like.

The polyester film is preferably a biaxially oriented film and preferably has a thickness of 3 to 260 μm.

In the present invention, an easily adhesive layer (primer layer)
The polyester resin (A) used for the formation of 0.01 to 30 mol% of a carboxylic acid group and / or its base (eg, a base such as an alkali metal salt, an ammonium salt, a quaternary amine salt or a phosphonium salt) in the side chain of the molecule ( (Based on all carboxylic acid components). Here, the molecular chain is
Means the ends and / or side chains of polymer molecules.

As the acid component constituting the polyester resin (A), terephthalic acid, isophthalic acid, phthalic acid, 2,
6-naphthalenedicarboxylic acid, hexahydroterephthalic acid, 4,4'-diphenyldicarboxylic acid, sebacic acid,
Succinic acid, butanetetracarboxylic acid, trimellitic acid, etc., and ethylene glycol as an alcohol component,
Diethylene glycol, neopentyl glycol, 1,
Examples thereof include 4-butanediol, 1,6-hexanediol, glycerin, trimethylolpropane, alkylene oxide adducts of bisphenol A, and dimethylolpropionic acid.

To introduce a carboxylic acid group into the molecular chain of the polyester resin (A), a polyfunctional compound having three or more functional groups, that is, a polyvalent carboxylic acid or a diol having a carboxylic acid group,
For example, trimellitic acid, dimethylolpropionic acid, trimesic acid, pyromellitic acid, succinic acid, trimellitic acid anhydride, butanetetracarboxylic acid dianhydride, succinic anhydride, etc. Good to use as. Further, in order to introduce a carboxylic acid group, one obtained by converting a part of the carboxylic acid group of the polycarboxylic acid to a carboxylic acid group or a diol having a carboxylic acid group is used as a part of the acid component or alcohol component of the polyester formation. It may be used, or the polyester having a carboxylic acid group in the molecular chain may be neutralized with an alkali metal hydroxide, ammonia, amine or the like.

The amount of the carboxylic acid group and its base in the polyester resin (A) is 0.01 per total carboxylic acid component.
-30 mol%, preferably 5-20 mol%. If this amount is less than 0.01 mol%, the hydrophilicity of the polyester will be poor and the stability of the water dispersion will be poor. On the other hand, if it exceeds 30 mol%, the flexibility of the primer layer (coating film) will decrease and adhesion will be poor. It is inferior in power and is not preferable.

The polyester resin (A) can be used in combination with a compound having at least one of an epoxy group, an aziridine group, an oxazoline group, a methylol group, an alkoxymethylol group and an isocyanate group as a cross-linking agent. In this case, carboxylic acid groups and carboxylic acid groups of the polyester resin are present in the coating solution, but these groups may react and disappear in the primer coating film.

In the present invention, an easily adhesive layer (primer layer)
The ethylene oxide-propylene oxide copolymer (B) used for the formation of the copolymer may be either a block copolymer or a random copolymer, but the former is preferred. The ratio of both components can be adjusted arbitrarily, but the weight ratio of ethylene oxide component / propylene oxide component is preferably 95/5 to 10/90. The average molecular weight is preferably 200 to 500,000, particularly preferably 500 to 30,000.

Polyester resin (A) and copolymer (B)
The weight% ratio of 96: 4 to 75:25, preferably 95:
It is preferably 5 to 80:20. Copolymer (B)
Is less than 4% by weight, the antistatic property becomes insufficient,
On the other hand, if it exceeds 25% by weight, the heat resistance will decrease.

In the present invention, the primer coating liquid contains, in addition to the polyester resin (A) and the copolymer (B),
Other resins, organic or inorganic fillers, colorants, surfactants, ultraviolet absorbers and the like can be added. The coating liquid can be used in any form such as an aqueous solution, an aqueous dispersion, an emulsion.

The application of the primer coating solution is applied to an unstretched film, a uniaxially stretched film, a biaxially stretched film and the like. It is preferable to apply these to a uniaxially stretched film stretched in the medium-longitudinal direction. In this case, after coating, transverse stretching, and in some cases, re-longitudinal stretching or re-lateral stretching can be performed. The stretching treatment can be performed under conventionally known conditions and methods. For example, the draw ratio is 2.5 times or more, preferably 3.0 times or more in each of the biaxial directions, and the area ratio is 8 times or more, preferably 8 to 30 times.

The thickness of the primer layer (coating film) is arbitrary, but is preferably 0.01 to 3 μm.

The easily adhesive polyester film thus obtained is excellent in adhesiveness, heat resistance and antistatic property,
In particular, it has excellent adhesion to magnetic paints, UV inks, etc.
It is also useful for packaging materials, printing materials, magnetic cards, magnetic tapes, magnetic disks, and the like.

[0025]

EXAMPLES The present invention will be further described below with reference to examples. Each characteristic value was measured by the following method.

1. Adhesiveness The coating material for evaluation is applied to the primer-coated polyester film with a Meyer bar so that the thickness after drying is about 4 μm, and dried at 100 ° C. for 3 minutes. After that, it was aged at 60 ° C for 24 hours, and then scotch tape No. 600 (3
Adhesive with a width of 12.7 mm and a length of 15 cm so that air bubbles do not enter, and the top of this is JIS C2701 (197).
5) Level with a manual load roll described in (3), bring it into close contact, and cut into a tape width. The strength when peeled at 180 degrees is measured. [Evaluation paint] Urethane resin Nipporan 2304 25 parts by weight (manufactured by Nippon Polyurethane) PVC / vinyl acetate resin S-REC A 50 parts by weight (Sekisui Chemical Co., Ltd.) Dispersant Resion P 1 part by weight (manufactured by RIKEN VITAMINS) Magnetic Agent CTX-860 500 parts by weight (manufactured by Toda Chemical Co., Ltd.) is dissolved in a mixed solvent of methyl ethyl ketone / toluene / cyclohexanone to make a 40% solution, which is then subjected to 2 with a sand glider.
Disperse in time. After that, 25 parts by weight of Coronate L (in terms of solid content) as a cross-linking agent is added and well stirred to obtain a magnetic coating material.

2. Antistatic properties Polyester film coated with primer on one side (10 μm x
(500 mm × 3000 m) is rewound at a speed of 150 m / min in an atmosphere of 23 ° C. × 75% RH, and the peeling charge of the roll is measured using a digital test electrical measuring instrument Model-203 manufactured by Hugle Electronics Co., Ltd. To do.

3. Heat resistance The primer surface of the primer-coated polyester film is brought into contact with a hot roll heated to 100 ° C. and having a surface speed of 4 m / min, and the surface of the roll is evaluated after 40 minutes. No foreign matter is seen on the roll surface .... Some foreign matter is seen on the roll surface. △ A large amount of foreign matter is seen on the roll surface.

[Example 1] An unstretched sheet of polyethylene terephthalate having an intrinsic viscosity of 0.62 was stretched 3.5 times in the machine direction, and terephthalic acid (90 mol%) was applied to one side thereof.
Isophthalic acid (2 mol%)-trimellitic acid (8 mol%)-ethylene glycol (60 mol%)-bisphenol A / ethylene oxide adduct (30 mol%) neopentyl glycol (10 mol%) in ammonia 80 wt% Japanese product (A-1), ethylene oxide (60
wt%)-propylene oxide (40 wt%) block copolymer (B-1) 10 wt% and a 5 wt% concentration aqueous solution of a composition consisting of 10 wt% silica having a particle size of 100 nm was applied by a roll coater. Then, while being dried, it is stretched 4.0 times in the transverse direction and heat-set at 225 ° C. to a thickness of 14 μm.
m film was obtained. The film thickness was 0.06 μm. The characteristics of this film are shown in Table 1.

[Comparative Example 1] The same procedure as in Example 1 was carried out except that the aqueous liquid was not applied. The properties of the obtained film are shown in Table 1.

[Examples 2 to 7, Comparative Examples 2 to 3] Example 1
In the same manner, except that the composition and ratio of the coated material were changed as shown in Table 1. The properties of the obtained film are shown in Table 1.

[0032]

[Table 1]

Note) <Polyester: A-2> 2,6-naphthalenedicarboxylic acid (75 mol%)-trimellitic acid (5 mol%)-isophthalic acid (20 mol%)-ethylene glycol (37)
Mol%)-neopentyl glycol (60 mol%)-dimethylolpropionic acid (3 mol%) copolymer trimethylamine neutralized product. <Polyester: A-3> Terephthalic acid (48 mol%)
-Isophthalic acid (10 mol%) trimellitic acid (42 mol%)-ethylene glycol (50 mol%)-neopentyl glycol (40 mol%)-1,4-butanediol (10 mol%) copolymer. <Ethylene oxide-propylene oxide copolymer: B
-2> ethylene oxide (50 wt%)-propylene oxide (50 wt%) block copolymer. <Surfactant: C-1> Polyoxyethylene nonylphenyl ether.

[0034]

EFFECT OF THE INVENTION The easily adhesive layer (primer layer) of the present invention comprises a polyester (A) having a specific amount of a carboxylic acid group and / or a base thereof in the molecule, and an ethylene oxide-propylene oxide copolymer (B). ) Is used in combination, it has excellent adhesiveness and heat resistance, and it is difficult to be charged due to the effects of both components. Further, the ethylene oxide-propylene oxide copolymer (B) has relatively good hydrophilicity, improving the wettability of the coating solution and improving the characteristics during coating. In addition, if the heat resistance of the primer layer is good,
Prevents abrasion by rolls during coating during the film forming process. It exhibits excellent properties as an adhesive property for magnetic paints, UV inks, etc. Since the chargeability is lowered, various troubles can be avoided when the easily-adhesive polyester film is secondarily processed.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location B32B 27/08 8413-4F C08L 67/02 LPF

Claims (3)

[Claims] 1. A polyester resin having (A) a carboxylic acid group and / or a base thereof in an amount of 0.01 to 30 mol% (based on all carboxylic acid components) in a molecular chain on at least one surface of the polyester film, and (B) ethylene oxide. -An easily-adhesive polyester film formed by coating an easily-adhesive layer using a propylene oxide copolymer. 2. The weight ratio of the ethylene oxide component to the propylene oxide component of the copolymer (B) is 95: 5 to 10:
90. The easily adhesive polyester film according to claim 1, which is 90. 3. The weight ratio of the polyester resin (A) to the copolymer (B) is 96: 4 to 75:25.
The easily-adhesive polyester film described.