JPH11342576A - Laminated thermoplastic film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the laminated thermoplastic film excellent in adhesion, water resistance and solvent resistance. SOLUTION: A layer containing a polyester graft copolymer wherein a polymerizable unsaturated monomer containing at least one monomer containing an acid anhydride having a double bond is grafted on a hydrophobic polyester resin and an acrylic resin is provided on at least the single surface of a thermoplastic film base material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoplastic film having improved adhesiveness,
Adhesive at the time of lamination, metal and inorganic or their oxide thin film can be used for a wide range of applications, high adhesion,
An object of the present invention is to provide a thermoplastic film having water resistance and solvent resistance.

[0002]

2. Description of the Related Art Conventionally, films made of thermoplastic resins such as polyolefin, polystyrene, polystyrene, polyvinyl chloride, polyester, and polyamide, particularly films of oriented polypropylene, polyester, and polyamide have excellent mechanical properties, It is widely used because of its heat resistance and transparency. In particular, biaxially stretched polyester films have excellent mechanical strength, heat resistance, chemical resistance, and dimensional stability, so they can be used as base films for magnetic tapes, insulating tapes, photographic films, tracing films, food packaging films, etc. It is even used in many areas. However, since a polyester film generally has low adhesiveness, when laminating a magnetic material, a photosensitive agent, a matting agent, or the like, it is common to apply a corona discharge treatment to the film surface or provide an anchor coating agent. Numerous materials have been proposed as an anchor coating agent, and among them, for a film having relatively high polarity mainly of polyester, it is possible to use a water-soluble or water-dispersible polyester resin or an acrylic resin. Proposed. (JP-A-54-43017, JP-B-49-10243, JP-A-52-19786, JP-A-52-19787, etc.)

[0003] However, the above-mentioned polyester resin has a drawback that blocking tends to occur when the film is wound into a roll, and the acrylic resin has poor adhesion to the film and the layer coated with the primer layer. There are drawbacks. Therefore, for the purpose of improving these drawbacks, it has been proposed to use a mixture of the polyester resin and the acrylic resin (Japanese Patent Application Laid-Open No. 58-12465).
No. 1), however, the improvement of the shortcomings is not enough.

Further, it has been proposed to use various modified polyesters mainly for graft modification. For example, JP-A 2-3307, JP-A 2-117243, JP-A 2-3100
No. 48 discloses that a resin obtained by grafting an unsaturated bond-containing compound to a water-soluble or water-dispersible hydrophilic group-containing polyester resin is suitable as a primer for a polyester film. However, the graft modification of a resin in which a hydrophilic group is previously contained in a polyester resin by copolymerization or the like does not have a high degree of adhesion and water resistance.

Further, Japanese Patent Application Laid-Open No. 3-273015, Japanese Patent Publication No. 3-67626
Also discloses that graft modified resins of polyester are useful as primers for polyester films. However, these resins are also poor in cohesive force, so that the adhesiveness in a dry state is improved, but the adhesiveness under wetness is poor. At present, there are problems such as peeling and scratching.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a laminated thermoplastic film having excellent adhesiveness, water resistance and solvent resistance, with the object of solving the above problems.

[0007]

According to the present invention, an acid anhydride having a double bond to a hydrophobic polyester resin is contained on at least one surface of a thermoplastic substrate film and at least one surface of a thermoplastic film substrate. At least one monomer
The above-mentioned object can be achieved by a laminated thermoplastic film comprising a layer containing a polyester-based graft copolymer grafted with a polymerizable unsaturated monomer containing a seed and an acrylic resin. In a preferred embodiment of the present invention, the adhesion modifying layer is applied to an unstretched or uniaxially stretched film with a coating liquid containing a polyester-based graft copolymer and an acrylic resin, and after drying, the coated film is further coated. A laminated thermoplastic film formed by uniaxially or more stretching and heat setting. In a further preferred embodiment of the present invention, the polymerizable unsaturated monomer contains at least a combination of maleic anhydride and styrene.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The term "grafting" of a self-crosslinkable polyester-based graft copolymer in the present invention refers to the introduction of a branch polymer composed of a polymer different from the main chain into the main chain of the main polymer. .

(Graft Polymer) The graft polymerization of the present invention generally comprises reacting a radical initiator and a radical polymerizable monomer mixture in a state in which a hydrophobic copolymerized polyester resin is dissolved in an organic solvent. It is implemented by. The reaction product after the completion of the grafting reaction is, in addition to the graft polymer between the desired hydrophobic copolymerized polyester-radical polymerizable monomer mixture, the hydrophobic copolymerized polyester that has not been grafted and the hydrophobic copolymerized polyester. It also contains a radical polymer not grafted to the polymerized polyester, but the graft polymer in the present invention includes all of them.

In the present invention, the acid value of a reaction product obtained by graft-polymerizing a radical polymerizable monomer onto a hydrophobic copolymerized polyester resin is preferably at least 600 eq / 10 ⁶ g. More preferably, the acid number of the reactants is 1200 eq
/ 10 ⁶ g or more. The reaction product has an acid value of 600 eq / 1
Is less than 0 ⁶ g, the adhesion between the layer to be coated in a is primed material object of the present invention is not sufficient.

The weight ratio of the hydrophobic copolymerizable polyester resin and the radical polymerizable monomer suitable for the purpose of the present invention is as follows: polyester / radical polymerizable monomer = 4
The range is preferably 0/60 to 95/5, more preferably 55/45 to 93/7, most preferably 60/40 to 9/9.
It is in the range of 0/10. When the weight ratio of the hydrophobic copolymerized polyester resin is less than 40% by weight, excellent adhesiveness of the polyester resin cannot be exhibited. on the other hand,
95% by weight of hydrophobic copolymerized polyester resin
When it is larger, blocking, which is a drawback of the polyester resin, tends to occur.

The graft polymerization reaction product of the present invention is in the form of a solution or dispersion of an organic solvent or a solution or dispersion of an aqueous solvent. In particular, a dispersion of an aqueous solvent, that is,
The form of the water-dispersed resin is preferred in view of working environment and applicability. In order to obtain such a water-dispersed resin, usually, in an organic solvent, the hydrophobic copolymerized polyester resin is graft-polymerized with a radical polymerizable monomer containing a hydrophilic radical polymerizable monomer, This is achieved by adding water and distilling off the organic solvent. The water-dispersed resin of the present invention has an average particle size of 500 nm or less as measured by a laser light scattering method, and exhibits a translucent or milky white appearance. By adjusting the polymerization method, water-dispersed resins having various particle diameters can be obtained. The particle diameter is suitably from 10 to 500 nm, and from the viewpoint of dispersion stability, is preferably 400 nm or less, more preferably 300 nm or less.
nm or less. If it exceeds 500 nm, the gloss of the surface of the coating film is reduced, and the transparency of the coating is reduced.
Below, the water resistance, which is the object of the present invention, is reduced,
Not preferred.

The hydrophilic radically polymerizable monomer used in the polymerization of the aqueous dispersion resin in the present invention refers to a group having a hydrophilic group or a group which can be converted into a hydrophilic group later. As a radical polymerizable monomer having a hydrophilic group, a carboxyl group, a hydroxyl group, a phosphoric acid group, a phosphorous acid group, a sulfonic acid group, an amide group,
A radical polymerizable monomer containing a quaternary ammonium base or the like can be given. On the other hand, as radical polymerizable monomers that can be converted to hydrophilic groups, acid anhydride groups, glycidyl groups,
Chlorine and the like can be mentioned. Among these, a carboxyl group is preferable from the viewpoint of water dispersibility, and a radical polymerizable monomer having a carboxyl group or a group generating a carboxyl group is preferable. From the viewpoint of increasing the acid value of the present invention, it is preferable that the compound contains a carboxyl group or contains a radical polymerizable monomer that generates a carboxyl group.

The glass transition temperature of the graft copolymer is not particularly limited, but is preferably 30 ° C. or lower. By using a graft copolymer having a glass transition temperature of 30 ° C. or lower for the adhesion modifying layer, a laminated thermoplastic film having particularly excellent adhesion can be obtained.

(Polyester) In the present invention, the hydrophobic copolymerized polyester resin must be essentially water-insoluble and does not originally disperse or dissolve in water.
When a polyester resin that disperses or dissolves in water is used for graft polymerization, the adhesiveness and water resistance, which are the objects of the present invention, deteriorate. The composition of the dicarboxylic acid component of the hydrophobic copolyester resin is from 60 to 60 aromatic dicarboxylic acids.
It is preferably 99.5 mol%, 0 to 40 mol% of aliphatic dicarboxylic acid and / or alicyclic dicarboxylic acid, and 0.5 to 10 mol% of dicarboxylic acid containing a polymerizable unsaturated double bond. When the amount of the aromatic dicarboxylic acid is less than 60% by mole or when the amount of the aliphatic dicarboxylic acid and / or the alicyclic dicarboxylic acid exceeds 40% by mole, the adhesive strength decreases. When the amount of the dicarboxylic acid containing a polymerizable unsaturated double bond is less than 0.5 mol%, efficient grafting of the radical polymerizable monomer to the polyester resin becomes difficult, and conversely, 10 mol% If it exceeds, the viscosity is undesirably increased too late in the late stage of the grafting reaction, preventing uniform progress of the reaction. More preferably, the aromatic dicarboxylic acid is 70 to 98 mol%, the aliphatic dicarboxylic acid and / or the alicyclic dicarboxylic acid is 0 to 30 mol%, and the dicarboxylic acid containing a polymerizable unsaturated double bond is 2 to 98 mol%.
7 mol%.

Examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, orthophthalic acid, naphthalenedicarboxylic acid, biphenyldicarboxylic acid and the like. It is preferable not to use a hydrophilic group-containing dicarboxylic acid such as 5-sodium sulfoisophthalic acid from the viewpoint of reducing the water resistance, which is the object of the present invention. Examples of the aliphatic dicarboxylic acid include succinic acid, adipic acid, azelaic acid, sebacic acid, dodecandionic acid, and dimer acid.Examples of the alicyclic dicarboxylic acid include 1,4-cyclohexanedicarboxylic acid and 1,4-cyclohexanedicarboxylic acid. Examples thereof include 3-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, and acid anhydrides thereof. Examples of dicarboxylic acids containing a polymerizable unsaturated double bond include, as α, β-unsaturated dicarboxylic acids, fumaric acid, maleic acid, maleic anhydride, itaconic acid, citraconic acid, and unsaturated double bonds. Examples of the alicyclic dicarboxylic acid include 2,5-norbornene dicarboxylic anhydride and tetrahydrophthalic anhydride. Of these, fumaric acid, maleic acid, and 2,5-norbornene dicarboxylic acid are preferred from the viewpoint of polymerizability.

On the other hand, the glycol component has 2 to 10 carbon atoms.
And / or an alicyclic glycol having 6 to 12 carbon atoms and / or an ether bond-containing glycol. Examples of the aliphatic glycol having 2 to 10 carbon atoms include ethylene glycol, 1,2-propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 3-methyl-1,
5-pentanediol, 1,9-nonanediol, 2-
Ethyl-2-butylpropanediol and the like can be mentioned, and as the alicyclic glycol having 6 to 12 carbon atoms,
1,4-cyclohexanedimethanol and the like can be mentioned.

Examples of the ether bond-containing glycol include diethylene glycol, triethylene glycol, dipropylene glycol, and glycols obtained by adding ethylene oxide or propylene oxide to two phenolic hydroxyl groups of bisphenols, such as 2,2-glycol. Bis (4-hydroxyethoxyphenyl) propane and the like can be mentioned. Polyethylene glycol, polypropylene glycol and polytetramethylene glycol can also be used if necessary.

In the copolymerized polyester resin used in the present invention, 0 to 5 mol% of a trifunctional or higher polycarboxylic acid and / or polyol can be copolymerized.
Examples of trifunctional or higher polycarboxylic acids include (anhydride) trimellitic acid, (anhydrous) pyromellitic acid, (anhydrous) benzophenonetetracarboxylic acid, trimesic acid, ethylene glycol bis (anhydrotrimellitate), glycerol tris (anhydride) Hydrotrimellitate) and the like are used. On the other hand, as trifunctional or higher polyols, glycerin, trimethylolethane, trimethylolpropane,
Pentaerythritol and the like are used. The trifunctional or higher polycarboxylic acid and / or polyol is copolymerized in the range of 0 to 5 mol%, preferably 0 to 3 mol%, based on the total acid component or total glycol component. Gelation at the time of polymerization tends to occur, which is not preferable.

The molecular weight of the hydrophobic copolyester resin is preferably in the range of 5,000 to 50,000 on a weight average. When the molecular weight is less than 5000, the adhesive strength is reduced, and conversely 50
If it exceeds 000, problems such as gelation during polymerization will occur.

(Polymer containing polymerizable unsaturated monomer) Monoesters or diesters of fumaric acid such as fumaric acid, monoethyl fumarate, diethyl fumarate and dibutyl fumarate, which exemplify the polymerizable unsaturated monomer of the present invention. Maleic acid and its anhydrides, monoethyl or maleic acid monoethyl or diethyl maleate, maleic acid monoesters or diesters such as dibutyl maleate, itaconic acid and its anhydrides, itaconic acid monoesters or diesters, maleimides such as phenylmaleimide, etc. Styrene, α-methylstyrene, t-butylstyrene, styrene derivatives such as chloromethylstyrene, vinyltoluene, divinylbenzene and the like. The acrylic polymerizable monomer, for example,
Alkyl acrylate, alkyl methacrylate (the alkyl group is a methyl group, an ethyl group, an n-propyl group,
Isopropyl group, n-butyl group, isobutyl group, t-butyl group, 2-ethylhexyl group, cyclohexyl group, phenyl group, benzyl group, phenylethyl group, etc.): 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2- Hydroxypropyl acrylate,
Hydroxy-containing acrylic monomer of 2-hydroxypropyl methacrylate: acrylamide, methacrylamide, N-methylmethacrylamide, N-methylacrylamide, N-methylolacrylamide, N-methylolmethacrylamide, N, N-dimethylolacrylamide, N- Amide group-containing acrylic monomers of methoxymethyl acrylamide, N-methoxymethyl methacrylamide, N-phenylacrylamide: N, N-diethylaminoethyl acrylate, amino group-containing acrylic monomers of N, N-diethylaminoethyl methacrylate: glycidyl acrylate , Glycidyl methacrylate epoxy group-containing acrylic monomers: carboxyls such as acrylic acid, methacrylic acid and their salts (sodium salt, potassium salt, ammonium salt) Sill group or an acrylic monomer containing the salts thereof. Preferred are maleic anhydride and its esters. The above monomers can be copolymerized by using one kind or two or more kinds.

The graft polymerization of the present invention is generally carried out by reacting a radical initiator and a radical polymerizable monomer mixture in a state where a hydrophobic copolymerized polyester resin is dissolved in an organic solvent. The reaction product after the completion of the grafting reaction is, in addition to the graft polymer between the desired hydrophobic copolymerized polyester-radical polymerizable monomer mixture, the hydrophobic copolymerized polyester that has not been grafted and the hydrophobic copolymerized polyester. It also contains a radical polymer not grafted to the polymerized polyester, but the graft polymer in the present invention includes all of them.

(Polymerization Initiator and Other Additives) As the graft polymerization initiator that can be used in the present invention, organic peroxides and organic azo compounds known to those skilled in the art can be used. As an organic peroxide, benzoyl peroxide, t-butyl peroxypivalate, as an organic azo compound,
Examples thereof include 2,2′-azobisisobutyronitrile and 2,2′-azobis (2,4-dimethylpareronitrile).

The amount of the polymerization initiator used for performing the graft polymerization is at least 0.2% by weight, preferably 0.5% by weight or more, based on the polymerizable monomer. In addition to the polymerization initiator, a chain transfer agent for adjusting the chain length of the branch polymer, for example, octyl mercaptan, mercaptoethanol, 3-t-butyl-4-hydroxyanisole, or the like can be used as necessary. In this case, it is desirable to add in the range of 0 to 5% by weight based on the polymerizable monomer.

(Reaction Solvent) The grafting reaction solvent for carrying out the present invention is preferably composed of an aqueous organic solvent having a boiling point of 50 to 250 ° C. Here, the aqueous organic solvent has a solubility in water at 20 ° C. of at least 10 g /
L or more, desirably 20 g / L or more.
Those having a boiling point exceeding 250 ° C. are unsuitable because the evaporation rate is too slow to remove sufficiently even by baking the coating film at a high temperature. When the boiling point is 50 ° C. or less,
When the grafting reaction is carried out using it as a solvent, 50
The use of an initiator that decomposes into radicals at a temperature of not more than ° C. increases the danger in handling, which is not preferred.

The first group of aqueous organic solvents which dissolves the copolymerized polyester resin well and dissolves the polymerizable monomer mixture containing the carboxyl group-containing polymerizable monomer and the polymer relatively well includes esters and the like. For example, ethyl acetate, ketones such as methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, cyclic ethers such as tetrahydrofuran, dioxane, 1,3-dioxolan, glycol ethers such as ethylene glycol dimethyl ether, propylene glycol methyl ether, propylene Glycol propyl ether, ethylene glycol ethyl ether, ethylene glycol butyl ether, carbitols such as methyl carbitol, ethyl carbitol, butyl carbitol, glycols or glycol ether; Lower esters such as ethylene glycol diacetate, ethylene glycol ethyl ether acetate, ketone alcohols such as diacetone alcohol, and N-substituted amides such as dimethylformamide, dimethylacetamide and N-methylpyrrolidone can be exemplified. .

On the other hand, as a second group of aqueous organic solvents, which hardly dissolve the copolymerized polyester resin but contain the carboxyl group-containing polymerizable monomer and the polymer which dissolves the polymer relatively well. , Water, lower alcohols, lower carboxylic acids, lower amines, etc., and particularly preferable for the practice of the present invention are alcohols and glycols having 1 to 4 carbon atoms.

When the grafting reaction is carried out with a single solvent, it can be carried out by selecting only one kind from the first group of aqueous organic solvents. When using a mixed solvent, there are a case where a plurality of types are selected only from the first group of aqueous organic solvents, and a case where at least one type is selected from the first group of aqueous organic solvents and at least one type is added from the second group of aqueous organic solvents.

In both cases where the graft polymerization reaction solvent is a single solvent from the first group of aqueous organic solvents, and when it is a mixed solvent composed of one kind of each of the first and second groups of aqueous organic solvents. A graft polymerization reaction can be performed. However, there are differences in the progress of the grafting reaction, the appearance and properties of the grafting reaction product and the aqueous dispersion derived therefrom, and a mixed solvent composed of one of the first and second groups of aqueous organic solvents, respectively. It is preferable to use

In the first group of solvents, the copolyester molecular chains are in a state of extended chains, while in the mixed solvent of the first group / second group, they are in a state of entanglement in a small-spread thread. This was confirmed by measuring the viscosity of the copolymerized polyester in these solutions. It is effective to prevent gelation by adjusting the dissolution state of the copolymerized polyester so as to prevent intermolecular crosslinking. Both high efficiency of grafting and suppression of gelation are achieved in the latter mixed solvent system. The weight ratio of the mixed solvent of the first group / second group is more preferably from 95/5 to 10/90, further preferably 90/10.
-20/80, most preferably 85 / 15-30 / 70
Range. The optimum mixing ratio is determined according to the solubility of the polyester used.

(Water dispersion) The grafting reaction product according to the present invention is preferably neutralized with a basic compound.
By neutralizing, it can be easily dispersed in water. As the basic compound, a compound which volatilizes at the time of forming a coating film or at the time of baking and curing by adding a curing agent is desirable, and ammonia, organic amines and the like are preferable. Examples of desirable compounds include triethylamine, N, N-diethylethanolamine, N, N-dimethylethanolamine, aminoethanolamine, N-methyl-N, N-diethanolamine,
Isopropylamine, iminobispropylamine, ethylamine, diethylamine, 3-ethoxypropylamine, 3-diethylaminopropylamine, sec-butylamine, propylamine, methylaminopropylamine, dimethylaminopropylamine, methyliminobispropylamine, 3-methoxy Examples thereof include propylamine, monoethanolamine, diethanolamine, and triethanolamine.

The pH of the aqueous dispersion of the basic compound can be adjusted to at least 5.0-9.% By neutralization at least partially or completely depending on the carboxyl group content contained in the grafting reaction product. It is desirable to use it so that it is in the range of 0. If a basic compound having a boiling point of 100 ° C. or less is used, the residual basic compound in the coating film after drying is small, and the adhesiveness of a metal or an inorganic vapor-deposited film or the water resistance when laminated with other materials. Excellent hot water adhesion. When a basic compound having a temperature of 100 ° C. or higher is used or the drying conditions are controlled, and the basic compound is left in the coating film after drying at 500 ppm or more, the transferability of the printing ink is improved.

In the aqueous dispersion produced according to the present invention,
The weight average molecular weight of the polymer of the radical polymerizable monomer is 500-
Preferably it is 50000. It is generally difficult to control the weight-average molecular weight of the polymer of the radical polymerizable monomer to 500 or less, and the grafting efficiency tends to decrease, and there is a tendency that the hydrophilic group is not sufficiently provided to the copolymerized polyester. is there. Further, the graft polymer of the radical polymerizable monomer forms a hydrated layer of the dispersed particles, but in order to provide a hydrated layer having a sufficient thickness and obtain a stable dispersion, The weight average molecular weight of the graft polymer is desirably 500 or more. Further, the upper limit of the weight average molecular weight of the graft polymer of the radical polymerizable monomer is preferably 50,000 from the viewpoint of polymerizability in solution polymerization. The control of the molecular weight within this range can be carried out by appropriately combining an initiator amount, a monomer dropping time, a polymerization time, a reaction solvent, a monomer composition or, if necessary, a chain transfer agent and a polymerization inhibitor.

In the present invention, a reaction product obtained by graft-polymerizing a radically polymerizable monomer onto a hydrophobic copolymerized polyester resin has a self-crosslinking property. Does not crosslink at room temperature,
With the heat during drying, an intermolecular reaction such as a hydrogen abstraction reaction by a thermal radical is performed, and crosslinking is performed without a crosslinking agent. Thereby, the adhesiveness and water resistance, which are the objects of the present invention, can be expressed for the first time. Although the crosslinkability of the coating film can be evaluated by various methods, it can be determined by the insoluble fraction in a chloroform solvent that dissolves both the hydrophobic copolymerized polyester resin and the radical polymer. Dry at 80 ° C or less, 5 at 120 ° C
The insoluble content of the coating film obtained by the heat treatment for 50 minutes is preferably 50% or more, more preferably 70% or more. When the insoluble content of the coating film is less than 50%, not only the adhesion and water resistance are not sufficient, but also blocking occurs.

The present invention provides a self-crosslinkable polyester grafted with a polymerizable unsaturated monomer, characterized in that the hydrophobic polyester resin contains at least one monomer containing an acid anhydride having a double bond. It is a substance which imparts high adhesiveness, water resistance and solvent resistance by adding an acrylic resin to the system graft copolymer. The acrylic resin may be either a solvent-based resin or an aqueous resin, and can be selected according to the application and the production method. When applying and stretching during the film forming process, an aqueous acrylic resin is preferred.

The acrylic resin as another component of the present invention is a conventionally known one and is not particularly limited. Known monomers can be used as the monomer component constituting the acrylic resin. For example, alkyl acrylate, alkyl methacrylate (the alkyl group is a methyl group,
Ethyl group, n-propyl group, t-butyl group, 2-ethylhexyl group, lauryl group, stearyl group, cyclohexyl group, phenyl group, benzyl group, phenylethyl group, etc.), 2-hydroxylethyl acrylate, 2-hydroxypropyl acrylate , A hydroxy group-containing monomer such as 2-hydroxypropyl methacrylate, acrylamide, N-methylacrylamide, N-methylolacrylamide, N-methylolmethacrylamide, N,
Amide group-containing monomers such as N-dimethylolacrylamide, N-methoxymethylacrylamide and N-phenylacrylamide; amino group-containing monomers such as N, N-diethylaminoethyl acrylate and N, N-diethylaminoethyl methacrylate; glycidyl acrylate;
Epoxy group-containing monomers such as glycidyl methacrylate,
Examples include monomers containing a carboxyl group or a salt thereof such as acrylic acid, methacrylic acid and salts thereof (lithium salt, sodium salt, potassium salt, etc.), and these are copolymerized using one or more kinds. You. Furthermore,
These can be used in combination with other types of monomers.

Examples of other types of monomers include epoxy group-containing monomers such as allyl glycidyl ether, and sulfonic acids such as styrene sulfonic acid, vinyl sulfonic acid and salts thereof (lithium salt, sodium salt, potassium salt, ammonium salt, etc.). The group has a carboxyl group such as a monomer containing the salt thereof, crotonic acid, itaconic acid, maleic acid, fumaric acid and salts thereof (lithium salt, sodium salt, potassium salt, ammonium salt, etc.) or a salt thereof. Monomers, monomers containing acid anhydrides such as maleic anhydride and itaconic anhydride, vinyl isocyanate, allyl isocyanate, styrene, vinyl methyl ether, vinyl ethyl ether, vinyl trisalkoxysilane, alicyl maleic acid monoester, alkyl fumaric acid Monoester, Ac Ronitoriru, methacrylonitrile,
Examples thereof include alkyl itaconic acid monoester, vinylidene chloride, vinyl acetate, and vinyl chloride.

As the acrylic resin of the present invention, a modified polyester copolymer, for example, a block copolymer or a graft copolymer modified with acryl, urethane, epoxy or the like can be used. The molecular weight of the acrylic resin of the present invention is preferably 100,000 or more, more preferably 300,000 or more, from the viewpoint of adhesion.

A self-crosslinkable polyester graft copolymer grafted with a polymerizable unsaturated monomer, characterized in that the hydrophobic polyester resin contains at least one monomer containing an acid anhydride having a double bond. The blending ratio of the coalesced and acrylic resin may be selected according to the application, and is not limited.

In the present invention, it is possible to impart high adhesiveness, water resistance and solvent resistance by adding a crosslinking agent. As the cross-linking agent, a cross-linking reaction is caused by heat or light with a functional group or the like present in the self-cross-linkable polyester-based graft copolymer onto which the polymerizable unsaturated monomer is grafted. It is a substance capable of forming a structure and is not particularly limited.

Examples of the cross-linking agent include phenol-formaldehyde resins of condensates with formaldehyde such as alkylated phenols and cresols; urea, melamine,
Adducts of benzoguanamine and the like with formaldehyde,
An amino resin such as an alkyl ether compound comprising the adduct and an alcohol having 1 to 6 carbon atoms; a polyfunctional epoxy compound; a polyfunctional isocyanate compound; a blocked isocyanate compound; a polyfunctional aziridine compound;
Oxazoline compounds and the like can be used.

As the phenol formaldehyde resin, for example, alkylated (methyl, ethyl, propyl,
Isopropyl or butyl) phenol, p-tert
-Amylphenol, 4,4'-sec-butylidenephenol, p-tert-butylphenol, o-, m
-, P-cresol, p-cyclohexylphenol,
4,4′-isopropylidenephenol, p-nonylphenol, p-octylphenol, 3-pentadecylphenol, phenol, phenyl o-cresol, p
-Condensates of phenols such as phenylphenol and xylenol with formaldehyde.

Examples of the amino resin include methoxylated methylol urea, methoxylated methylol N, N-ethylene urea, methoxylated methylol dicyandiamide, methoxylated methylol melamine, methoxylated methylol benzoguanamine, butoxylated methylol melamine, and butoxylated methylol benzoguanamine. And methoxylated methylolmelamine, butoxylated methylolmelamine, and methylolated benzoguanamine.

Examples of the polyfunctional epoxy compound include diglycidyl ethers of bisphenol A and oligomers thereof, diglycidyl ethers of hydrogenated bisphenol A and oligomers thereof, diglycidyl orthophthalate, diglycidyl isophthalate, and the like.
Diglycidyl terephthalate, diglycidyl p-oxybenzoate, diglycidyl tetrahydrophthalate, diglycidyl hexahydrophthalate, diglycidyl succinate, diglycidyl adipate, diglycidyl sebacate, ethylene Glycol diglycidyl ether, propylene glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether and polyalkylene glycol diglycidyl ethers, trimellitic acid triglycidyl ester, triglycidyl isocyanurate ,
1,4-diglycidyloxybenzene, diglycidylpropylene urea, glycerol triglycidyl ether,
Examples include trimethylolpropane triglycidyl ether, pentaerythritol triglycidyl ether, and triglycidyl ether of a glycerol alkylene oxide adduct.

As the polyfunctional isocyanate compound,
Low-molecular or high-molecular aromatic or aliphatic diisocyanates and trivalent or higher polyisocyanates can be used. Examples of the polyisocyanate include tetramethylene diisocyanate, hexamethylene diisocyanate, toluene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate, and trimers of these isocyanate compounds. Further, an excess amount of these isocyanate compounds and a low-molecular active hydrogen compound such as ethylene glycol, propylene glycol, trimethylolpropane, glycerin, sorbitol, ethylenediamine, monoethanolamine, diethanolamine, triethanolamine, or polyester polyols, Examples thereof include a terminal isocyanate group-containing compound obtained by reacting a polymer active hydrogen compound such as ether polyols and polyamides.

The blocked isocyanate can be prepared by subjecting the above isocyanate compound and a blocking agent to an addition reaction by a conventionally known appropriate method. Examples of the isocyanate blocking agent include phenols such as phenol, cresol, xylenol, resorcinol, nitrophenol, and chlorophenol; thiophenols such as thiophenol and methylthiophenol; oximes such as acetoxime, methyl etiketoxime, and cyclohexanone oxime. Alcohols such as methanol, ethanol, propanol and butanol; halogen-substituted alcohols such as ethylene chlorohydrin and 1,3-dichloro-2-propanol; t-butanol and t-
Tertiary alcohols such as pentanol; ε-caprolactam, δ-valerolactam, ν-butyrolactam, β
Lactams such as propyl lactam; aromatic amines; imides; active methylene compounds such as acetylacetone, acetoacetate ester, and malonic acid ethyl ester; mercaptans; imines; ureas; diaryl compounds; Can be mentioned.

These crosslinker bonds can be used alone or in combination of two or more. The compounding amount of the crosslinking agent is 1 part by weight to 4 parts by weight based on 100 parts by weight of the grafted copolymer.
0 parts by weight is preferred. As a method of compounding the crosslinking agent,
(1) When the crosslinking agent is water-soluble, a method of dissolving or dispersing it directly in an aqueous solvent solution or dispersion of the graft copolymer, or (2) When the crosslinking agent is oil-soluble, after completion of the grafting reaction And a method of adding to a reaction solution. These methods can be appropriately selected depending on the type and properties of the crosslinking agent. Further, a curing agent or an accelerator can be used in combination with the crosslinking agent.

The combination of the self-crosslinkable polyester-based graft copolymer and the cross-linking agent can be used as it is in the present invention to form an adhesion-modified layer. However, for other purposes, a general-purpose polyester-based resin or polyurethane-based resin can be used. , Their copolymers, various water-soluble resins, etc., and various functional resins, such as conductive resins such as polyaniline and polypyrrole, antibacterial resins, UV-absorbing resins, and gas-barrier resins. May be formed.

Additives such as various surfactants, antistatic agents, inorganic lubricants, organic lubricants, antibacterial agents, photooxidation catalysts, ultraviolet absorbers, etc. are added to the adhesion modifying layer as long as the effects of the present invention are not impaired. Can be contained.

As the coating liquid, an organic solvent solution or dispersion of a self-crosslinkable polyester-based graft copolymer and a cross-linking agent constituting the adhesion modifying layer, or an aqueous solvent solution or aqueous solvent dispersion can be used. In particular, an aqueous solution or dispersion is preferable in that an organic solvent which is problematic for the environment is not used. The solid content of the self-crosslinkable polyester-based graft copolymer and acrylic resin in an organic solvent or an aqueous solvent is usually 1% by weight to 50% by weight, preferably 3% by weight to 30% by weight.

There are no particular restrictions on the drying conditions of the graft copolymer after application. However, in order to exhibit the self-crosslinking property of the graft copolymer, the base film and the graft copolymer suffer from thermal deterioration. As long as it does not occur, a condition for increasing the amount of heat is preferable. Specifically, the temperature is from 80C to 250C, more preferably from 150C to 220C. However, by extending the drying time, sufficient self-crosslinking property is exhibited even at a relatively low temperature, so that the conditions are not limited to the above.

The method for applying a coating solution containing a self-crosslinkable polyester-based graft copolymer and an acrylic resin to a thermoplastic film substrate to form an adhesion-modified layer includes a gravure method, a reverse method, and a die method. Known coating methods such as a method, a bar method, and a dip method can be used.

The coating amount of the coating solution is 0.00
5~5g / m ^2, preferably, 0.02 to 0.5 g / m
² When the coating amount becomes 0.005 g / m ² or less,
Sufficient adhesive strength with the adhesion modified layer cannot be obtained. 5g / m
^If it is more than ² , blocking occurs, and there is a practical problem.

The adhesion-modified layer may be formed by coating the above-mentioned coating solution on a thermoplastic film substrate after biaxial stretching, or by coating the above-mentioned coating solution on unstretched or uniaxially stretched thermoplastic film substrate. After the drying, the film may be dried, and if necessary, may be further subjected to heat setting after uniaxial stretching or biaxial stretching.

In the case where the above coating solution is applied to the unstretched or uniaxially stretched polyamide film substrate and then dried and stretched, the drying temperature after the application needs to be dried under conditions that do not affect the subsequent stretching. Yes, for polyamide base,
The film is stretched by setting the moisture content to 2% or less and then heat-set at 200 ° C. or more, whereby the coating film becomes strong, and the adhesiveness between the adhesion-modified layer and the polyester film substrate is remarkably improved. When the water content is 2% or more, it depends on the drying temperature,
In some cases, crystallization occurs and the crystallization becomes cheaper, and the flatness is deteriorated and the stretchability is impaired.

When applied to a biaxially stretched thermoplastic film substrate, the thermoplastic film substrate is subjected to corona treatment, flame treatment, electron beam irradiation to further improve the adhesiveness between the thermoplastic film substrate and the adhesion modifying layer. Surface treatment such as irradiation may be performed. Even when the film is stretched after the following application, the same effect can be obtained.

The adhesion-modified layer of the laminated thermoplastic film substrate of the present invention has good adhesion to various materials, but in order to further improve the adhesion and printability, the adhesion-modified layer is further treated with corona. Surface treatment by flame treatment, electron beam irradiation, or the like may be performed.

The adhesive modified layer of the laminated thermoplastic film substrate obtained in the present invention can provide good adhesive strength in a wide range of applications. Specifically, printing inks, UV inks, adhesives such as dry laminations and extrusion laminations, vacuum deposition of metal or inorganic substances or oxides thereof, electron beam deposition, sputtering, ion plating, CV
D, a thin film layer or an oxygen absorbent layer obtained by plasma polymerization or the like,
Examples include an organic barrier layer and an inkjet image receiving layer.

EXAMPLES Hereinafter, the present invention will be described with reference to examples. In the examples, “parts” means “parts by weight”, and “%” means “% by weight”. Each measurement item followed the following method.

1) Evaluation of Adhesiveness (Preparation of Laminate) Gravure ink (Lamiace 61 white two-liquid type, on a corona-treated surface) or on the adhesion-modified layer of the laminated thermoplastic film obtained in each of Examples and Comparative Examples. Toyo Ink Co., Ltd.) is gravure printed to form a printing ink layer, and then an adhesive AD585 / CAT-10 (Toyo Morton Co., Ltd.) is applied at ² g / m ^2, and then an unstretched polypropylene film, 60 μm ( P1120, manufactured by Toyobo Co., Ltd.) by a dry lamination method to provide a sealant layer to obtain a thermoplastic film laminate. Peel strength in normal storage (dry and wet) and in 90 ° C. hot water was measured. Measurement conditions were 9 at a tensile speed of 100 mm / min.
It is a 0 degree peel test result.

2) Glass transition temperature (Tg) A solution or dispersion was applied to a glass plate,
To obtain a graft copolymer solid content. 10 mg of this solid content was placed in a sample pan, and 1
Tg was measured by scanning at a rate of 0 ° C./min.

(Preparation of copolymerized polyester) Dimethyl terephthalate 3 was placed in a stainless steel autoclave equipped with a stirrer, a thermometer, and a partial reflux condenser.
45 parts, 211 parts of 1,4 butanediol, 270 parts of ethylene glycol, and 0.5 part of tetra-n-butyl titanate were charged, and a transesterification reaction was performed from 160 ° C. to 220 ° C. for 4 hours. Then, fumaric acid 1
Add 4 parts and 160 parts of sebacic acid, and
The temperature was raised to 20 ° C. over 1 hour to carry out an esterification reaction. Then, the temperature was raised to 255 ° C., and the pressure in the reaction system was gradually reduced. Then, the reaction was carried out under a reduced pressure of 0.22 mmHg for 1 hour and 30 minutes to obtain a copolymerized polyester. The obtained polyester had a weight average molecular weight of 20,000 and was light yellow and transparent.

(Self-Crosslinkable Polyester Graft Copolymer) In a reactor equipped with a stirrer, a thermometer, a reflux device and a metered-dropping device, 75 parts of the above-mentioned copolymerized polyester resin, 56 parts of methyl ethyl ketone and isopropyl alcohol 1
Nine parts were added and heated and stirred at 65 ° C. to dissolve the resin.
After the resin was completely dissolved, 15 parts of maleic anhydride was added to the polyester solution. Next, a solution prepared by dissolving 10 parts of styrene and 1.5 parts of azobisdimethylvaleronitrile in 12 parts of methyl ethyl ketone was dropped into the polyester solution at a rate of 0.1 ml / min, and stirring was further continued for 2 hours. After sampling for analysis from the reaction solution, 5 parts of methanol was added. Next, 300 parts of water and 15 parts of triethylamine were added to the reaction solution, followed by stirring for 1 hour.
Thereafter, the reactor internal temperature was raised to 100 ° C., and methyl ethyl ketone, isopropyl alcohol, and excess triethylamine were distilled off to obtain a water-dispersed graft polymerization resin. The water-dispersed graft resin was pale yellow and transparent, and had a glass transition temperature of -10 ° C.

(Example 1)
Styrene / n-butyl acrylate
50-27 / 2-hydroxyethyl methacrylate
With water-based acrylic resin copolymerized at 23 (weight ratio)
Water so as to have a volume ratio of 90:10 and a solid concentration of 10%:
Dilute with isopropyl alcohol = 9: 1 (weight ratio)
The coating solution was adjusted. Melts nylon 6 resin at 280 ° C
Extruded and cooled with a cooling roll at 15 ° C to a thickness of 185μ
m of unstretched film, and the unstretched film is
3.5 times stretching in the longitudinal direction between a pair of different rolls at 85 ° C
did. Next, apply the coating liquid by a roll coater method.
And dried with hot air at 70 ° C.
Stretched 3.5 times in the transverse direction at 200 ° C,
15μm thick biaxially stretched laminated polyamide film
Got Lum. Final coating agent application amount is 0.07 g / m
^TwoMet.

Example 2 Polyethylene terephthalate was melt-extruded at 280 ° C. and cooled with a cooling roll at 15 ° C. to obtain an unstretched film having a thickness of 100 μm. And stretched 3.5 times in the machine direction. Next, the coating solution of Example 1 was applied by a roll coater method, dried with hot air at 70 ° C., and then stretched 3.5 times in a transverse direction at 98 ° C. with a tenter.
A biaxially stretched laminated polyester film having a thickness of 12 µm was obtained by heat fixing at 00 to 210 ° C. The final coating agent application amount was 0.08 g / m ² .

(Comparative Example 1) The coating solution of Example 1 was prepared by diluting only the aqueous acrylic resin with water: isopropyl alcohol = 9: 1 (weight ratio) so that the solid content concentration became 10%. Otherwise by performing the same operations as in Example 1, a biaxially stretched coated polyamide film having a thickness of 15 μm was obtained. The final coating agent application amount is 0.07 g / m ²
Met.

Comparative Example 2 A biaxially stretched coated polyester film having a thickness of 12 μm was obtained in the same manner as in Example 2 except that the coating liquid of Example 2 was used as the coating liquid of Comparative Example 1. The final coating agent application amount is 0.08 g /
m ² .

(Comparative Example 3) Thickness 1 manufactured by Toyobo Co., Ltd.
A 5 μm biaxially stretched polyamide film was used.

(Comparative Example 4) Thickness 1 manufactured by Toyobo Co., Ltd.
A 2 μm biaxially stretched polyester film was used.

[0070]

[Table 1]

[0071]

The present invention provides excellent adhesion, water resistance and solvent resistance by providing a layer comprising a self-crosslinkable polyester-based graft copolymer and an acrylic resin on a thermoplastic film. Is obtained.

Claims (3)

[Claims] 1. A polyester in which a polymerizable unsaturated monomer containing at least one monomer containing an acid anhydride having a double bond to a hydrophobic polyester resin is grafted on at least one surface of a thermoplastic film base material. A laminated thermoplastic film comprising a layer containing a graft polymer and an acrylic resin. 2. The layer according to claim 1, wherein a coating liquid containing a polyester-based graft copolymer and an acrylic resin is applied to an unstretched or uniaxially stretched film, and after drying, the film is further uniaxially or uniaxially stretched. A laminated thermoplastic film formed by stretching and then heat-setting. 3. A laminated thermoplastic film, wherein the polymerizable unsaturated monomer according to claim 1 contains at least maleic anhydride and styrene.