JPH0250835A - Coated plastic film - Google Patents

Abstract

PURPOSE:To obtain a plastic film excellent in adhesiveness in the presence of water by coating at least the single surface of a base film composed of a thermoplastic resin with a composition substantially based on water-insoluble water-dispersible specific polyester and specific polyurethane. CONSTITUTION:Water-insoluble water-dispersible polyester (a) consists of dicarboxylic acid containing 0.5-5mol.% of dicarboxylic acids having a metal sulfonate group and 50mol.% of aromatic dicarboxylic acid and polyhydric alcohols and has glass transition temp. of 100 deg.C or less. Water-insoluble water- dispersible polyurethane (b) is obtained from dicarboxylic acid containing 50mol.% or more of aliphatic dicarboxylic acids, a polyester component composed of glycols and a dissocyanate component. Polyester (a) and polyurethane (b) are contained in the composition in a wt. ratio of 95:5-30:70. This composition is applied at least to the single surface of a base film. As the base film, a film composed of a thermoplastic resin such as polyester can be used.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention provides a plastic film useful for various uses such as packaging materials, magnetic tapes, and photographic films.

In particular, a printed layer and a vapor deposited layer formed on the film.

The present invention relates to a coated plastic film that has extremely excellent adhesion to a magnetic powder-containing layer, even in the presence of water.

(Prior art) Various thermoplastic films, especially biaxially oriented polyester, polyamide, polyolefin, etc. films, are used as packaging films, decorative films, photographic base films, magnetic tape base films, drafting films, etc. Use of.

It is also widely used in other industrial applications.

These films are rarely used alone; instead, they are printed or thinly coated with metal on the surface of the base plastic film, have a resin layer containing magnetic material formed, or are laminated with other films. Often used. However, the above-mentioned base film and the layers laminated on its surface [e.g., printing layer, metal vapor deposition layer, magnetic material-containing resin layer, ceratin layer (in the case of photographic film), matting material layer (in the case of drafting film) etc.] Adhesion (adhesion)
is not necessarily sufficient. For example, a heat-seal film in which a heat-seal layer made of polyolefin resin is laminated on the surface of a metal-deposited polyester base film (such as a polyethylene terephthalate film) has gas barrier properties, moisture impermeability, and visible light/ultraviolet light. Because of its excellent shielding properties, it is used as a packaging material for foods, industrial parts, etc., or as a protective coating. However, these laminated films generally have poor adhesion at the interface between the base film and the metal-deposited layer, particularly in the presence of water. Therefore, for example, when food is packaged with such a film, there is a drawback that the vapor-deposited layer easily peels off when boiling treatment is performed for the purpose of sterilization.

As a method for improving the adhesive force between a polyester base film and a thin metal layer, for example, as disclosed in Japanese Patent Publication No. 55232 and Japanese Patent Application Laid-open No. 56-16549, other copolymer compositions are mixed in addition to polyester. A method for preparing a base film is disclosed. Furthermore, JP-A-57-8
Japanese Patent Publication No. 7357 discloses a method of physically changing the surface condition of a base film, and Japanese Patent Publication No. 59-51424 discloses a method of applying a specific resin composition solution to the surface of a base film to change the resin composition. A method of forming a layer of material is disclosed. However, even if these methods are adopted, the adhesion between the base film or laminate film and the metal vapor-deposited layer is still not sufficient, especially in the presence of water (especially hot water). is insufficient. moreover.

Among the above methods, the method of applying a resin composition solution described in Japanese Patent Publication No. 59-51424 uses an aqueous solvent, so there are concerns about flammability and toxicity, resulting in operational hazards. It is also unfavorable from the viewpoint of pollution generation and energy saving.

Various methods have also been proposed aimed at improving the adhesion between polyester-based films and printing inks, photographic emulsions, matting agents, magnetic paints, or other types of paints. For example, as a method for improving the adhesion between the base film and the printing layer, Japanese Patent Publication No. 55-45835 and Japanese Patent Publication No. 55-12870 disclose a method of blending polyester of a specific composition into the base film. Disclosed. This method improves adhesion and provides some adhesion even in the presence of water. However, when using this method, relatively excellent effects can be obtained when the layer laminated on the base film is a printed layer, but when other layers 1, for example, a metal vapor deposited layer, water sufficient adhesion cannot be obtained in the presence of water, especially in the presence of hot water.

As an undercoat to improve the adhesion between a polyester base material and a layer laminated thereon, 1, for example, JP-A-48-3748
No. 0 discloses a specific polyester polyether copolymer resin composition. Although these resin compositions have good adhesion to the polyester base material, their adhesion to the core layer may be insufficient depending on the composition of the layers to be laminated. For example, adhesion to layers formed by paints containing relatively highly polar components or metal vapor deposited layers is often insufficient. Furthermore, since an organic solvent is used when applying the resin composition to the base material, as in the case of the above-mentioned Japanese Patent Publication No. 59/51424,
It poses a work hazard due to its flammability and toxicity.

A method for forming an undercoat layer on a base film without using an organic solvent is described in Japanese Patent Publication No. 5446557.
A method of applying an aqueous solution containing a composition whose ingredients have been changed to be water-soluble is disclosed.

However, since the compositions used are essentially water-soluble,9 they suffer from the disadvantage that, for example, the resulting printed or vapor-deposited films have poor water resistance. Also in the manufacturing process, aqueous solvents have a disadvantage in that they have poor wettability with hydrophobic base films, making it difficult to obtain a uniform coating film.

In this way, any layer formed on the plastic base film, such as the printing layer, heat-sealing layer, metal vapor deposition layer, or magnetic paint layer, has good adhesion, especially in the presence of water. At present, there is no plastic film that can be subjected to boiling treatment.

(Problem to be solved by the invention) The present invention solves the above-mentioned conventional problems.

The purpose is to provide a plastic film that has excellent interlayer adhesion, particularly in the presence of water, with printed layers, heat seal layers, metal vapor deposited layers, magnetic paint layers, etc.

(Means and Effects for Solving the Problems) The coated plastic film of the present invention includes a base film made of a thermoplastic resin, and at least one side of which is substantially water-insoluble and water-dispersible polyester (a) and polyurethane (b). ), wherein the substantially water-insoluble and water-dispersible polyester (a) contains a dicarboxylic acid having a sulfonic acid metal base at a concentration of 0. consisting of a dicarboxylic acid containing aromatic dicarboxylic acid in a proportion of 5 to 5 mol% and a proportion of 50 mol% or more, and a polyhydric alcohol; the glass transition temperature of the polyester is 100°C or less;
The substantially water-insoluble and water-dispersible polyurethane (b
) is obtained from a polyester component consisting of a dicarboxylic acid containing aliphatic dicarboxylic acids in a proportion of 50 mol % or more and glycols; and a diisocyanate component; and the polyester (a) and the polyurethane (
b) is contained in the composition in a weight ratio of 95:5 to 30:70, thereby achieving the above object.

As the base film used in the coated plastic film of the present invention, any film made of thermoplastic resin such as polyester, polyamide, polyolefin, etc. can be used. Among them, polyester films such as polyethylene terephthalate and polybutylene terephthalate.

Polyester films such as polyethylene nuclate are preferred. In particular, a copolyester film in which 80% or more of its components correspond to polyethylene terephthalate (that is, 80% or more of the total components are terephthalic acid components and ethylene glycol components) or a polyester blend containing polyethylene terephthalate in a proportion of 80% or more A film is preferably used. The polyester components other than the polyethylene terephthalate component in such a copolymerized polyester film or polyester blend film may be any polyester component. The dicarboxylic acid component constituting such polyester is aromatic.

Both aliphatic and cycloaliphatic dicarboxylic acids can be used. Examples of aromatic dicarboxylic acids include isophthalic acid, orthophthalic acid, and 2,6-naphthalene dicarboxylic acid; examples of aliphatic dicarboxylic acids include succinic acid, adipic acid, sebacic acid, and oxalic acid; and alicyclic dicarboxylic acids. Examples include 1°3-cyclobencuenedicarboxylic acid and 4-cyclohexanedicarboxylic acid. As the aromatic dicarboxylic acid, some oxyacids such as p-hydroxybenzoic acid are also suitably used. The glycol component constituting the above polyester has 2 or more carbon atoms.
8 aliphatic glycols or alicyclic glycols having 6 to 12 carbon atoms are preferred. Such glycols include ethylene glycol 1,2-propanediol,
1,3-propanediol, 1,4-butanediol,
Neopentyl glycol, 1,6-hexanediol,
1,2-cyclohexane dimetatool, 1,3-cyclohexane dimetatool, 1,4-cyclohexane dimetatool.

p-xylene glycol, diethylene glycol.

These include triethylene glycol. In addition, it is also possible to use polyether glycols as aliphatic glycols, such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and the like.

These acid components and dicarboxylic acid components are polymerized (or copolymerized) by a conventional method to prepare a polyester. This polyester is mixed as appropriate, and a film (base film) is usually obtained by melting and extrusion or by melting and casting in a solvent. The base film used is as required.

- axially or biaxially stretched;

Among the resins contained in the composition used for the coating layer formed on the surface of the base film, polyester (a)
is substantially water-insoluble and water-dispersible, and the dicarboxylic acid component constituting the polyester accounts for 0.5
~5 mol% is a dicarboxylic acid with a sulfonic acid metal salt (having a metal sulfonate) group, as described above;
And 50 mol% or more is aromatic dicarboxylic acid. Here, "substantially water-insoluble" means that even if the polymer to be tested is immersed in hot water of 80°C and stirred, the polymer does not dissipate in the hot water. More specifically, the polymer to be tested is made into chips, which are then exposed to a large excess of hot water (
80°C) and stirred for 24 hours, the weight loss of the polymer is 5% by weight or less.

The sulfonic acid metal base-containing dicarboxylic acids contained in such polyesters include sulfoterephthalic acid, 5
Examples include metal salts of -sulfoisophthalic acid, 4-sulfophthalic acid, 4-sulfonaphthalene-27-dicarboxylic acid, and 5(4-sulfophenoxy]isophthalic acid.

Particularly suitable are 5-sodium sulfoisophthalic acid and sodium sulfoterephthalic acid. When the amount of such dicarboxylic acids is below 0.5 mol%.

The dispersibility of the obtained polyester-containing composition in water is impaired, and as a result, it becomes difficult to form a uniform coating film, and the adhesion between the obtained coating film and the printed layer or metal vapor deposited layer is reduced. On the other hand, if it exceeds 5 mol %, the adhesive performance in the presence of water, especially when the layer to be laminated is a metal vapor deposited layer, deteriorates. Generally, it is preferable that the dicarboxylic acid containing a sulfonic acid metal group be used in a small amount within a range that does not impair the dispersibility in water of the resulting polyester-containing composition (which varies depending on the component 1 dispersion method, etc.).

As the dicarboxylic acid other than the dicarboxylic acid having a sulfonic acid metal group, any aromatic or aliphatic alicyclic dicarboxylic acid may be used, but the aromatic dicarboxylic acid is 50 mol% or more, preferably 70 mol%. % or more. Examples of aromatic dicarboxylic acids include terephthalic acid, isofucric acid, orthophthalic acid, and 2,6-naphthalene dicarboxylic acid. When the amount of aromatic fatty acids is too low, the mechanical strength of the film formed from the resulting polyester-containing composition and the adhesion in the presence of water (particularly in the presence of hot water) will be poor.

Aliphatic dicarboxylic acids include disuccinic acid, adipic acid,
Sepacic acid, etc. are examples of alicyclic dicarboxylic acids such as 1,
3-Cyclopencune dicarboxylic acid.

Examples include (1), 2-cyclohexanedicarboxylic acid, (2), 3-cyclohexanedicarboxylic acid, and 1,4-cyclohexanedicarboxylic acid. Among these non-aromatic dicarboxylic acid components, aliphatic dicarboxylic acids are effective in improving the water dispersibility of the resulting polyester-containing composition and the adhesion of the coated film obtained by applying the polyester. However, if it is in excess, the mechanical strength and adhesion in the presence of hot water of the film formed from the resulting polyester-containing composition will be reduced. Although the alicyclic dicarboxylic acid may improve the adhesive performance of the obtained coated film in the presence of water, if it is in excess, it reduces the water dispersibility of the obtained polyester.

As the glycol component contained in the polyester used in the coating layer, an aliphatic glycol having 2 to 8 carbon atoms or an alicyclic glycol having 6 to 12 carbon atoms is used. Such glycols include ethylene glycol, 2-propanediol, 1,3-propanediol, 1,4-butanediol, neopentyl glycol, 1,6-hexanediol, and 1,2-cyclohexane dimetatool.

1.3-Cyclohexane dimetatool 1.4-Cyclohexane dimetatool, p-xylylene glycol, bisphenol compounds, diethylene glycol, triethylene glycol and the like.

Using the above dicarboxylic acid component and polyhydric alcohol component 7
Polyesters are usually prepared by a melt polycondensation method. For example, a direct esterification method in which each of the above components is directly reacted, water is distilled off and esterified, and triple condensation is performed; or the dialkyl ester of the dicarboxylic acid component and the glycol component are reacted to distill off the alcohol and esterify. It is prepared by a transesterification method that involves exchange and polycondensation. In addition to the melt polymerization method, a solution polycondensation method, an interfacial polycondensation method, etc. may also be employed.

The water-insoluble and water-dispersible polyester thus obtained must have a glass transition temperature (Tg) of 100°C or less. The glass transition temperature is preferably 80°C or less, more preferably 20 to 80°C. If the glass transition temperature exceeds 100°C, film forming properties when applying the composition containing the polyester to a base film will be poor, resulting in insufficient adhesion between the resulting coating layer and the base film.

As a result, the adhesion between the obtained coating film and the layer 3 laminated thereon, such as a metal vapor deposition layer, is also poor.

The lower limit of the above-mentioned glass transition temperature is not particularly limited, but it is preferably 20°C or higher in consideration of the blocking properties and hot water resistance of the resulting coating film.

Among the resins contained in the composition used for the coating layer, polyurethane (b) is also substantially water-insoluble and water-dispersible. The term "substantially water-insoluble" as used herein has the same meaning as in the case of the polyester (a). Such polyurethane (b) is a polyurethane obtained from a polyester polyol and a diisocyanate; or a prepolymer of the polyurethane;
A polyurethane obtained by reacting a low-molecular compound having two or more active hydrogens, such as a diol or diamine, is used.

The above polyester polyol is obtained by reaction of dicarboxylic acid and glycol. As these dicarboxylic acids and glycols, compounds similar to the dicarboxylic acids and glycols that can constitute the polyester (a) can be used, and 50 mol% of the dicarboxylic acid component,
Preferably, 70 mol% or more of the dicarboxylic acid should be aliphatic dicarboxylic acid. If the amount of aliphatic dicarboxylic acid is too small, the resulting composition containing polyurethane will be inferior in film-forming properties and adhesion to the substrate when applied to the substrate film. In particular, when stretching is performed after coating on an unstretched base film, the coating layer follows the base material and is not sufficiently stretched, resulting in cracks. As the glycol component, it is preferable to use alkylene glycols having 4 or more carbon atoms (eg, butanediol, hexanediol) in combination with alicyclic glycols (eg, cyclohexane dimetatool) or bisphenol compounds. The polyester polyol can be prepared by polycondensing the above dicarboxylic acid and glycol in the same manner as for the polyester in (a).

The diisocyanates reacted with the polyester polyol obtained in this way include aromatic, aliphatic,
and alicyclic diisocyanates may be used. For example, aromatic diisocyanates such as toluene diisocyanate.

suitable. A coating film formed by a composition containing a polyurethane obtained using such an aromatic diisocyanate has high strength, and also has excellent adhesion in the presence of water to the vapor-deposited layer of the resulting coating film.

Polyurethane (b) is obtained by reacting the above polyester polyol with the above diisocyanate by a conventional method. Furthermore, it is also possible to extend the chain by reacting a low-molecular compound having two or more active hydrogens, such as a diol or diamine. As the diol, 1,4-butanediol, 1,6 hexanediol, etc. can be used, and as the diamine, ethylenediamine, 6-hexamethylenediamine, etc. can be used.

The above polyester (a) and polyurethane (b) are.

It is contained in the composition forming the coating layer in a weight ratio of 95=5 to 30, preferably 90:10 to 50:50.

If polyester (a) is present in excess, the resulting coated film will have poor adhesion in the presence of water, and polyurethane (b)
) is excessive, the adhesion of the coating layer to the base material and film forming properties will be poor.

In addition to the water-insoluble polyester (a) and polyurethane (b), a resin component having crosslinking properties may be added to the composition forming the coating layer. Examples of such resins include melamine-based, epoxy-based, aziridine-based, and urethane-based resins. By containing these, the effect of preventing blocking of the obtained coating layer and improving the solvent resistance can be obtained. However, they have disadvantages in that they reduce the stability of aqueous dispersions of compositions containing them and that it is difficult to melt and reuse the resulting coating film.

Furthermore, when the coating film is subjected to metal vapor deposition, there is a drawback that the metallic luster decreases or the coating film tends to become transparent when it is treated with hot water. Therefore, the above-mentioned crosslinking component is added as appropriate depending on the purpose.

The composition may further contain other additives. Examples include various water-dispersed resins, inorganic inert particles such as silica, calcium carbonate, kaolinite alumina, talc, and barium sulfate; organic inert particles such as henzoguanamine resins and polystyrene resins (all of which are particles). (diameter of about 0.01 to 10 μm), and by adding these, slipping properties and anti-blocking properties can be improved.

Further, pigments; organic and inorganic antistatic agents; preservatives; antifoaming agents; ultraviolet absorbers and the like may be used as necessary. The type and amount of additives are not particularly limited as long as they do not significantly inhibit the interlayer adhesion of the resulting film in the presence of water.

The composition to be coated onto the base film can be made into an aqueous dispersion by various methods. for example.

Regarding the water-insoluble polyester (a), a method of adding the polyester fine particles to hot water and dispersing it under strong stirring; a method of dispersing the water-insoluble polyester in water together with a water-soluble organic compound, etc. may be adopted. Among these, a method using a water-soluble organic compound (usually an organic solvent) is particularly suitable.

The organic compound used usually has a boiling point of 60 to 20
0°C and 1 at 20°C! The amount of solubility in water is 2
0g or more of the compound is used. These include aliphatic and cycloaliphatic alcohol 7 ethers, ester ketones, and the like. Alcohols include monohydric alcohols such as methanol, ethanol, isopropanol, and n-butasol; glycols such as ethylene glycol and propylene glycol; and glycol 8 excellent conductors such as methyl cellosolve, ethyl cellosol, and n-butyl cellosol. . Examples of ethers include dioxanetetrahydrofuran; examples of esters include dioxanetetrahydrofuran.

Examples of ketones include ethyl acetate and the like; examples of ketones include methyl ethyl ketone. Two or more of these water-soluble organic compounds can also be used in combination. Among the above-mentioned compounds, butyl cellosolve and ethyl cellosolve can be preferably used in view of their dispersibility in water and coating performance on films.

Using such water-soluble organic compounds, polyester (a
) To prepare an aqueous dispersion, the polyester chips and the water-soluble organic compound are mixed at 50 to 200°C, water is added thereto, and the mixture is stirred and dispersed;
A method in which the mixture obtained by mixing at 0 to 200°C is added to water and stirred to disperse the mixture; Alternatively, the above polyester, water-soluble organic compound, and water are mixed at 40 to 120°C.
A method of stirring and dispersing is adopted. It is also possible to use an emulsifier for dispersion, but in this case the water resistance of the resulting coating film is somewhat reduced.

Regarding the polyurethane (b), a method in which the polyurethane fine particles and an emulsifier are added to water and dispersed under strong stirring; when synthesizing the polyurethane.

A method in which polyurethane (prepolymer) having an isocyanate group at the end, water, a chain extender, and an emulsifier are added to water and reacted under strong stirring to simultaneously perform dispersion and polymerization using mechanical shearing force; on the side of the polyurethane. A method of dispersing by imparting self-emulsifying properties by introducing an ionic group such as an amino group or a carboxyl group to the chain or terminal is used. Considering the water resistance of the resulting coating, a method that does not use an emulsifier is desirable.

The above dispersion of polyester (a) and polyurethane (b) is mixed, and various additives are added as necessary, or these additives are appropriately added in the dispersion step described in Section 2 to form a uniform aqueous dispersion. is prepared.

The aqueous dispersion is applied onto the base film by a known method. For example, the above dispersion is applied onto an unstretched base film obtained by melting and extrusion, or a base film obtained by uniaxially or biaxially stretching the unstretched film, and if necessary, further stretching and post-stretching are performed. Heat treatment is performed. A biaxially oriented film obtained by coating a dispersion on an unstretched or axially stretched base film, further axially or biaxially stretching, and heat treatment, or adhesion of the coating layer;
This is preferable from the viewpoints of transparency and economy. Particularly from the viewpoint of workability, it is preferable to apply a dispersion liquid onto a -axially stretched base film and then stretch the dispersion in a direction orthogonal to the second direction to obtain a biaxially stretched film. For coating the above aqueous dispersion,
Roll coating method (gravure method, reverse method, etc.)
Any known method such as , knife coating method, loft coating method, nozzle coating method, or air knife coating method may be employed. What is the coating amount?

Although it is determined depending on the purpose, the amount of the composition present per unit area (m2) of the final coated film obtained by biaxial stretching etc. is usually 0.005 to 5 g.

Preferably it is 0.01 to Ig. Coating amount is 0.005
If it is less than 5g/m2, the desired effect will not be obtained;
When it exceeds 2, blocking of the resulting coated film is likely to occur. When applying the aqueous composition dispersion, the surface of the base film may be subjected to corona treatment 2 or physical or chemical surface treatment, if necessary.

The plastic coated film of the present invention thus obtained is used for various purposes. The surface of the coating layer of this film is printed by a normal method, or
A heat seal layer and an adhesive layer for bonding the heat seal layer are laminated.

Alternatively, a vapor-deposited layer of metal such as aluminum, an aluminum foil layer, or the like is laminated as the gas barrier layer. In particular, sheets or films made of various resin materials can be laminated on a vapor-deposited layer obtained by vapor-depositing metals or metal oxides on the coating layer, and this can be suitably used for food packaging materials, etc. Such a laminate does not peel off even when immersed in hot water. The resin materials constituting the sheets and films to be laminated include polyethylene, polypropylene,
Various ionomers, ethylene-vinyl acetate copolymers, polyvinylidene chloride copolymers, polyester polyamides, etc. are used. In the coated film of the present invention, since the resin composition having a specific composition is coated on the base film, interlayers between the substances forming the various layers formed on the coated film are Excellent adhesion, especially in the presence of water. Therefore, the coated film of the present invention is particularly suitably used as a food packaging film that is subjected to hot water sterilization treatment.

(Margin below) (Example) The present invention will be described below with reference to examples.

Preparation of Tsubasa Kando (A) polymer and aqueous dispersion: First, polyester (a) was prepared by the following method. Dimethyl terephthalate 49 mol% (total dicarboxylic acid components), dimethyl isophthalate 49 mol% as dicarboxylic acid components
and 2 mol% of sodium 5-sulfoisophthalate; and using 50 mol% of ethylene glycol (of the total glycol component) and 50 mol% of neopentyl glycol as glycol components, transesterification and polycondensation reactions were carried out in a conventional manner. . As a result, a polyester having a glass transition point of 69°C was obtained. 300 parts by weight of the obtained polyester and 150 parts by weight of monobutyl cellosolve were heated and stirred to form a viscous liquid. While stirring, 550 parts by weight of water was gradually added to the mixture to obtain a uniform pale white aqueous dispersion having a solid content of 30%.

Next, polyurethane (b) was prepared by the following method.

Adipic acid as the dicarboxylic acid component; and 1,4-butanediol as the polyol component.

A polyester (polyester polyol) was obtained using a propylene oxide (1 mol) adduct of bisphenol A and bisphenol A. This polyester was treated with toluene diisocyanate to obtain a urethane polymer. This was used as a prepolymer, and 1,6 hexanediol was applied to extend the chain and aminocarboxylate was reacted at the terminal end to obtain a water-insoluble and water-dispersible polyurethane (b). This was dispersed in hot water with stirring to obtain a 25% aqueous dispersion.

The above aqueous dispersion of polyester (a) and aqueous dispersion of polyurethane (b) were added to a mixture of equal amounts of ion-exchanged water and isopropyl alcohol so that the solid content of each was 4% and 1%. A homogeneous dispersion with a total solids content of 5% was obtained.

(B) Preparation of coated film: Polyethylene terephthalate was melt extruded at 280 to 300°C and cooled with a cooling roll at 15°C to obtain an unstretched film with a thickness of about 150 μm. This unstretched film was
The film was stretched 3.5 times in the machine direction between a pair of rolls at 5°C.

Next, the above coating dispersion was applied using a roll coater, dried with hot air at 70°C, and then heated at 98°C using a tenter.
Stretched 3.5 times in the transverse direction at C, and further stretched 200 to 210°
C. to obtain a biaxially stretched coated polyester film having a thickness of 12 μm. The final coated amount of the second agent (coating composition) was approximately 0.04 g/m2. Table 1 shows the properties, blending ratio, etc. of the resin forming the coating layer of the obtained coating film.

(C) Performance evaluation of coated film: Aluminum was vapor-deposited to a thickness of 600 mm on the surface of the coating layer of the coated film obtained in section (B). An unstretched polypropylene (PP) sheet having a thickness of 60 μm was laminated on the surface of this vapor-deposited layer by a conventional dry lamination method, and then an aging treatment was performed. The obtained laminate was cut into strips with a width of 15 mm, and the laminate was cut at 95°.
It was immersed in boiling water of C or higher for 30 minutes (boiling treatment). Using another sample, an experiment was also conducted in which the sample was immersed in high-pressure water at 120°C for 30 minutes (retort treatment).

Partially peeling off the PP film and the base film at the end of the untreated, boiled and retorted laminate;
The peeled ends were each fixed to a Tensilon chuck manufactured by Toyo Baldwin, and pulled in the length direction at a speed of 200 mm/min to perform T-peeling. A separate peeling experiment was conducted under similar conditions with water droplets applied to the peeled interface. Table 2 shows the interlayer adhesive strength (g/15mm) of each.

Implementation ±1 Same as Example 1 except that cyclohexane dimetatool was used instead of neopentyl glycol to obtain polyester (a) having a glass transition temperature of 82°C.

Properties of the resin forming the coating layer of the obtained coating film,
Table 1 shows the blending ratio.

Table 2 shows the performance evaluation of the coated film. Example 3 described below
- 4 and the results of Comparative Examples 1 to 8 are also shown in Table 1.
and shown in Table 2.

Example 1 is the same as Example 1 except that isophorone diisocyanate is used instead of toluene diisocyanate.

JL [L4-] Same as Example 1 except that the blending ratio of polyester (a) and polyurethane (b) was 60:40 (weight ratio).

The dicarboxylic acid components constituting the Hokkaido polyester (a) include 23 mol% dimethyl terephthalate, 22 mol% dimethyl isophthalate, and 53 mol% adipic acid.

The procedure was the same as in Example 1 except that 2 mol % of sodium 5-sulfoisophthalate was used to obtain a polyester having a glass transition temperature of 5°C.

Same as Example 1 except that 45 mol% of dimethyl terephthalate, 45 mol% of dimethyl isophthalate, and 10 mol% of sodium 5-sulfoisophthalate were used as dicarboxylic acid components constituting the Hokuranbumata polyester (a). It is.

As the dicarboxylic acid component constituting the comparative fuel polyester (a), 50 mol% of dimethyl terephthalate, 40 mol% of dimethicyisophthalate and 10 mol% of sodium 5-sulfoisophthalate; and as the glycol component,
Same as Example 1 except that 50 mol% of ethylene glycol and 50 mol% of polyethylene glycol (14000 molecules) were used.

Comparative Example 4 As a dicarboxylic acid component constituting polyester (a), 70 mol% of dimethyl terephthalate, 25 mol% of dimethyl isotucrate, and 5 mol% of sodium 5-sulfoisophthalate; and as a glycol component, 30 mol% of ethylene glycol. The procedure was the same as in Example 1, except that 70 mol% of bisphenol A ethylene oxide adduct was used to obtain a polyester having a glass transition temperature of 103°C.

Instead of adipic acid used in the preparation of flame-retardant polyurethane (b), 50 mol% of terephthalic acid and 50% of isophthalic acid were used.
Same as Example 1 except that mol% was used.

Comparison Example 1 was the same as Example 1 except that the blending ratio of polyester (a) and polyurethane (b) was 96:4 (weight ratio).

Comparative Example The same as Example 1 except that the aqueous dispersion containing polyester (a) and polyurethane (b) was not applied.

(The following is a blank space) It can be seen from Tables 1 and 2 that the coated plastic film of the present invention exhibits excellent adhesion to the vapor deposited layer formed on its surface even in the presence of hot water. On the other hand, the film of Comparative Example 7 in which the coating layer made of the composition containing polyester (a) and polyurethane (b) was not formed did not have such an effect. If the composition of polyester (a) or polyurethane (b) in the composition forming the coating layer deviates from the scope of the claims, sufficient adhesion between the base material and the deposited layer, especially in the presence of hot water, may be required. No significant adhesion effect was obtained (Comparative Examples 1 to 3 and 5). When the Tg of polyester (a) is high as in Comparative Example 4.

Also, as in Comparative Example 6, when the blending ratio of polyester (a) and polyurethane (b) is out of the claimed range, a sufficient adhesive effect cannot be obtained.

(Effects of the Invention) According to the present invention, it has excellent adhesion to layers made of various polymers and inorganic substances, such as printed layers, metal vapor deposited layers, heat seal layers, and magnetic paint layers, which are laminated on the surface. A coated plastic film is obtained. Its adhesive strength is sufficient even in the presence of water, especially hot water. Such plastic films are used as food packaging films, insulation tapes,
It is used in applications such as base films for magnetic tapes, photographic films, and tracing films, and is particularly suitable for food packaging films that are subjected to heat treatment with hot water.

that's all

Claims (1)

[Claims] 1. On at least one side of the base film made of thermoplastic resin, substantially water-insoluble and water-dispersible polyester (
a) and polyurethane (b), the substantially water-insoluble and water-dispersible polyester (a)
) has 0 dicarboxylic acids with sulfonic acid metal bases.
．． dicarboxylic acids containing aromatic dicarboxylic acids in a proportion of 5 to 5 mol% and a proportion of 50 mol% or more; and polyhydric alcohols; the polyester has a glass transition temperature of 100°C or less; Water-insoluble and water-dispersible polyurethane (b
) is obtained from a polyester component consisting of a dicarboxylic acid containing aliphatic dicarboxylic acids in a proportion of 50 mol% or more and glycols; and a diisocyanate component, and the polyester (a) and the polyurethane (b) are Contained in the composition in a weight ratio of 95:5 to 30:70,
Coated plastic film. 2. The film according to claim 1, which is oriented in at least one axis.