JP5042161B2 - Easy adhesive film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an easily adhesive film getting an adhesive property on variable processings without using a crosslinking agent such as a melamine resin which has a feare of polluting the environment and also provided with a primer layer superior in heat resistance for a high temperature hot water. <P>SOLUTION: A coated film layer containing a polyester resin and also a crosslinking component containing 0 to 0.1 mass% or less is formed at least on one side on a substrate film. The polyester resin has a total of an acid value and a hydroxyl value of 50- 200 mgKOH/g, the acid value of 20-60 mgKOH/g and the hydroxyl value of 30-150 mgKOH/g, an oligomer contained in the polyester is not more than 2.0 mass%. The thickness of the coated film is 0.001-0.5 &mu;m. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to an easily adhesive film, and more particularly to an easily adhesive film suitable as a film used for packaging materials, electrical insulating materials, general industrial materials, and the like.

  Thermoplastic resin films are widely used as base films for packaging foods and general industries. In these applications, the surface of the base film is usually subjected to various secondary processes such as coating of various paints, printing processes, vapor deposition processes, and laminating processes with other films. Therefore, the substrate film can be subjected to physical treatment such as corona discharge treatment or plasma treatment, or chemical treatment that activates the film surface using chemicals such as acid and alkali. Attempts have been made to improve the surface of the film and increase the adhesion between the base film and the coating by the secondary processing. However, the physical treatment method has a simple process, but the resulting adhesiveness is insufficient. The method using chemical treatment has problems such as a complicated process and a deteriorated working environment.

  Apart from the physical and chemical treatment methods described above, an easy-adhesive coating film (hereinafter sometimes referred to as “primer layer”) is laminated in a laminated state by applying a primer having adhesive activity to the base film. There is a method of forming. This method is widely used because a primer component can be selected according to various topcoat layers (coating layers by secondary processing).

  As a constituent component of the primer layer, an aqueous resin is often used from the viewpoint of workability, safety and cost. In particular, a polyurethane resin, a polyester resin, an acrylic resin, or the like is used in order to improve adhesiveness with a coating layer, an ink layer, a vapor deposition layer, or the like that is a coating layer.

  In addition, various crosslinking agents are blended with the aqueous resin to improve performance as a primer, particularly water resistance and heat resistance. Examples of the crosslinking agent used for this purpose include isocyanate compounds and aminoplast resins (Patent Document 1). Patent Document 2 shows that the primer layer made of a polyester resin and a melamine resin improves the water-resistant adhesion of the vapor deposition layer. Patent Document 3 describes a method for obtaining an easily adhesive laminated film using a carbodiimide monomer containing one carbodiimide group per molecule.

Primer layers using these existing technologies tend to decrease interlaminar adhesion between the base film and the topcoat layer, especially when subjected to high-temperature hot water treatment such as boiling and retort. There is a problem with the practical performance. Therefore, in order to improve the adhesiveness after boiling and retorting, a method for maintaining high adhesiveness after retorting using an aqueous polyester resin having a glass transition point of 100 ° C. or higher and a melamine resin (Patent Document) 4) has been developed.
JP 56-151562 A Japanese Patent Laid-Open No. 8-311221 JP-A-8-332706 JP 2004-256625 A

  Due to the high interest in environmental issues in recent years, Japan's Air Pollution Control Act was amended in May 2004, and volatile organic compounds (VOC) were released into the atmosphere from April 1, 2006. Businesses that discharge and disperse are obliged to grasp the amount of emissions and control emissions. The melamine resin used as a crosslinking agent for the polyester resin is very excellent in liquid stability, physical properties after crosslinking, and the like. However, when a water-soluble melamine resin is used as the crosslinking agent, formaldehyde which is VOC is generated from the melamine resin, which may contaminate the environment. Furthermore, formaldehyde has been reported as a causative substance and carcinogenic substance of Housesick syndrome. For this reason, formalin-free product development is required in each field.

  An object of the present invention is to provide an easy-adhesive film having a primer layer that is excellent in adhesiveness during various processing and excellent in high-temperature hot water resistance without using a crosslinking agent such as a melamine resin.

As a result of intensive studies focusing on the acid value and hydroxyl value of the polyester resin used as the coating film constituting the primer layer, and the amount of oligomer, the present inventors have used a crosslinking agent by controlling these. It has been found that the surface properties of the coating are improved without it, thereby improving the adhesion of the coating and the properties under high humidity.
The gist of the present invention is as follows.

  (1) A coating film containing a polyester resin and containing 0 to 0.1% by mass or less of a crosslinking agent component is formed on at least one surface of the base film, and the acid value and hydroxyl value of the polyester resin are formed. The total valence is 50 to 200 mgKOH / g, the acid value is 20 to 60 mgKOH / g and the hydroxyl value is 30 to 150 mgKOH / g, and the amount of oligomer contained in the polyester is 2.0% by mass or less. An easily adhesive film, wherein the coating film has a thickness of 0.001 to 0.5 μm.

  (2) The surface carboxylic acid concentration and the surface hydroxyl group concentration of the coating film are both 0.005 or more, and the surface primary amine concentration of the coating film is 0.0001 or less (1) Easy adhesion film.

  (3) The easily adhesive film according to (1) or (2), wherein the crosslinking agent component is a melamine compound.

  (4) The easily adhesive film according to any one of (1) to (3), wherein the ratio of the hydroxyl value to the acid value of the polyester resin (hydroxyl value / acid value) is 2.0 to 5.0. .

  (5) The easily adhesive film according to any one of (1) to (4), wherein the polyester resin contains both a trivalent or higher polyvalent carboxylic acid component and a trivalent or higher polyhydric alcohol component.

  (6) The easily adhesive film according to (5), wherein the trivalent or higher polyvalent carboxylic acid component is trimellitic acid, and the trivalent or higher polyhydric alcohol component is trimethylolpropane.

  (7) In producing any one of the easy-adhesion films according to the above (1) to (6), the content of the cross-linking agent component containing the polyester resin as a main component on at least one surface of the base film before orientation crystallization By applying an aqueous coating composition containing 0 and 0.1% by mass or less to form a coating film, and then stretching the substrate film together with the coating film in at least one direction and heat-treating the substrate. A method for producing an easy-adhesion film, characterized by subjecting a material film to orientation crystallization.

  According to the present invention, an easy-adhesive film having excellent adhesion to a coating layer can be obtained even after processing such as coating, printing, and vapor deposition. The adhesion is maintained even after hot water treatment such as boiling and retort. Such an easily adhesive film of the present invention can be suitably used as a packaging material, an electrical insulating material, a general industrial material, or the like. This easy-adhesive film is particularly suitable for food packaging because it has excellent adhesion even after hot water treatment such as boil and retort treatment.

  Such excellent characteristics can be obtained without using a formaldehyde-generating substance such as a melamine compound as a crosslinking agent. For this reason, it can consider the surrounding environment at the time of film use.

  Furthermore, the easy-adhesion film of the present invention can be easily obtained by applying an aqueous coating material containing a polyester resin to a base film. For this reason, the film is excellent in productivity, such as being easy to control the thickness, and is industrially advantageous.

  The base film used for the easy-adhesion film of the present invention is not particularly limited as long as it is a film made of a thermoplastic resin. Examples of the production method include extrusion molding, injection molding, blow molding, stretch blow molding, and drawing. The base film may be a film composed of a single layer, or may be a film composed of a plurality of layers formed by simultaneous melt extrusion or lamination.

  Specific examples of the thermoplastic resin constituting the base film include an olefin copolymer, polyester, polyamide, styrene copolymer, vinyl chloride copolymer, acrylic copolymer, and polycarbonate. Of these, olefin copolymers, polyesters and polyamides are preferred.

  Examples of olefin copolymers include low-, medium- or high-density polyethylene, linear low density polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-butene copolymer, ionomer, and ethylene-vinyl acetate copolymer. And ethylene-vinyl alcohol copolymer. Examples of the polyester include polyethylene terephthalate, polybutylene terephthalate, polyethylene terephthalate / isophthalate, polyethylene naphthalate, and polylactic acid. Examples of the polyamide include nylon 6, nylon 66, nylon 610, metaxylylene adipamide, and the like. Examples of the styrene copolymer include polystyrene, styrene-butadiene block copolymer, styrene-acrylonitrile copolymer, styrene-butadiene-acrylonitrile copolymer (ABS resin) and the like. Examples of the vinyl chloride copolymer include polyvinyl chloride and vinyl chloride-vinyl acetate copolymer. Examples of the acrylic copolymer include polymethyl methacrylate and methyl methacrylate / ethyl acrylate copolymer. These thermoplastic resins may be used alone or in combination of two or more. Preferred thermoplastic resins include polyamide resins such as nylon 6, nylon 66, nylon 46; aromatic polyester resins such as polyethylene terephthalate, polyethylene naphthalate, polytrimethylene terephthalate, polybutylene terephthalate, polybutylene naphthalate; polylactic acid, etc. Aliphatic polyester resins of the above; polyolefin resins such as polypropylene and polyethylene; and mixtures thereof.

  If desired, one or more additives such as pigments, antioxidants, antistatic agents, ultraviolet absorbers, lubricants, and preservatives can be added to these thermoplastic resins. The blending amount of these additives is suitably in the range of 0.001 to 5.0 parts by mass as the total amount per 100 parts by mass of the resin.

  In the easy-adhesion film of the present invention, a reinforcing material can be blended with the base film in order to ensure strength when used as a packaging material or the like. As reinforcing materials, fiber reinforcing materials such as glass fibers, aromatic polyamide fibers, carbon fibers, pulp, cotton and linter; powder reinforcing materials such as carbon black and white carbon; flaky reinforcing materials such as glass flakes and aluminum flakes, etc. Is mentioned. These may be used alone or in combination of two or more. The blending amount of the reinforcing material is suitably 2 to 150 parts by mass as a total amount per 100 parts by mass of the thermoplastic resin.

  A filler such as heavy or soft calcium carbonate, mica, talc, kaolin, gypsum, clay, barium sulfate, alumina powder, silica powder, magnesium carbonate may be added to the base film for the purpose of increasing the amount. it can. One kind or two or more kinds of these fillers can be used. The amount used is suitably 5 to 100 parts by mass as the total amount per 100 parts by mass of the thermoplastic resin.

  For the purpose of improving gas barrier properties, the base film may be blended with scaly inorganic fine powders such as water-swellable mica and clay. The amount used is suitably 5 to 100 parts by mass as the total amount per 100 parts by mass of the thermoplastic resin.

  In this invention, the polyester resin used as a coating film is comprised from a polybasic acid component and a polyhydric alcohol component, and is manufactured by a well-known polymerization method. Only one type of polyester resin may be used, or two or more types of polyester resins may be used in combination. As will be described later, it is preferable that the polyester resin can be made water-based.

  Polybasic acid components of the polyester resin include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, orthophthalic acid, naphthalenedicarboxylic acid, biphenyldicarboxylic acid; oxalic acid, succinic acid, succinic anhydride, adipic acid, azelaic acid, Saturated or unsaturated aliphatic dicarboxylic acids such as sebacic acid, fumaric acid, maleic acid, maleic anhydride, itaconic acid, itaconic anhydride, citraconic acid, citraconic anhydride, dimer acid, etc .; 1,4-cyclohexanedicarboxylic acid, Examples thereof include 1,3-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 2,5-norbornene dicarboxylic acid and anhydrides thereof, and alicyclic dicarboxylic acids such as tetrahydrophthalic acid and anhydrides thereof.

  A tribasic or higher polybasic acid can be used. Examples of such polybasic acids include trimellitic acid, pyromellitic acid, benzophenone tetracarboxylic acid, trimellitic anhydride, pyromellitic anhydride, benzophenone anhydrous tetracarboxylic acid, trimesic acid, ethylene glycol bis ( Anhydro trimellitate), glycerol tris (anhydro trimellitate), 1,2,3,4-butanetetracarboxylic acid and the like. Among these, trimellitic acid is preferable from the viewpoints of adhesion, water dispersibility, and heat resistance. The tribasic or higher polybasic acid has a good water dispersibility of the resin, and the point that the acid value of the polyester resin and the surface carboxylic acid concentration of the coating film are the target values of the present invention. The polybasic acid component preferably contains 5 to 50 mol%, more preferably 10 to 40 mol%, and particularly preferably 15 to 30 mol%.

  Among the polybasic acids described above, it is preferable to use an aromatic polybasic acid. The content of the aromatic polybasic acid is preferably 40 mol% or more in the polybasic acid component of the polyester resin, more preferably 50 mol% or more, further preferably 60 mol% or more, It is especially preferable that it is 70 mol% or more. By increasing the proportion of the aromatic polybasic acid component, the proportion of the aromatic ester bond, which is harder to hydrolyze than the aliphatic and alicyclic ester bonds, in the resin skeleton increases, so that the storage stability of the aqueous resin dispersion is increased. As a result, the water resistance of the resulting resin film is improved, and at the same time, the processability and solvent resistance of the resin film are also improved.

  Among the above-mentioned aromatic polybasic acids, it is possible to improve the workability, hardness, hot water resistance, solvent resistance, weather resistance, etc. while balancing the various performances of the resin film as a coating film. Terephthalic acid, isophthalic acid, and naphthalenedicarboxylic acid are preferred.

  In order to improve the water dispersibility of the polyester resin, a component having a sulfo group such as 5-sodium sulfoisophthalic acid can be added as a copolymerization component. However, in that case, the water resistance of the resin film is lowered, and the adhesion after the hot water treatment such as boil and retort required by the present invention is greatly impaired. For this reason, it is preferable not to add the component which has a sulfo group.

  Examples of the polyhydric alcohol component of the polyester resin include aliphatic glycol, alicyclic glycol, ether bond-containing glycol and the like. Aliphatic glycols include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 2-methyl-1,3-propanediol, 1,5-pentanediol, neopentyl Examples include glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,9-nonanediol, and 2-ethyl-2-butylpropanediol. Examples of the alicyclic glycol include 1,4-cyclohexanedimethanol. Examples of the ether bond-containing glycol include diethylene glycol, triethylene glycol, and dipropylene glycol. Furthermore, ethylene oxide is added to two phenolic hydroxyl groups of bisphenols such as 2,2-bis (4-hydroxyethoxyphenyl) propane. Alternatively, glycols obtained by adding 1 to several moles of propylene oxide, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and the like can be given.

  Examples of the trifunctional or higher polyhydric alcohol include glycerin, trimethylolethane, trimethylolpropane, and pentaerythritol. Among these, trimethylol roll propane is preferable from the viewpoint of adhesion and water dispersibility. The trifunctional or higher polyhydric alcohol is preferably contained in the polyhydric alcohol component in an amount of 1 to 30 mol% in order to obtain the hydroxyl value of the polyester resin and the hydroxyl group concentration on the coating film surface as specified in the present invention. . It is more preferably 2 to 25 mol%, and particularly preferably 3 to 20 mol%.

  Among the polyhydric alcohol components described above, the diol component is particularly preferably ethylene glycol, butanediol, or neopentyl glycol. In that case, the total proportion of ethylene glycol, 1,4-butanediol and neopentyl glycol in the alcohol component of the polyester resin is preferably 50 mol% or more, more preferably 60 mol% or more, and 70 mol% or more. Particularly preferred. Since ethylene glycol, 1,4-butanediol, and neopentyl glycol are industrially mass-produced, they are inexpensive and well-balanced in performance as a resin film. These polyhydric alcohols particularly improve the chemical resistance and weather resistance of the resin coating.

  In the easily adhesive film of the present invention, the total valence of the acid value and the hydroxyl value of the polyester resin forming the coating film needs to be 50 to 200 mgKOH / g, preferably 60 to 150 mgKOH / g, and 70 to 110 mg KOH / g is more preferred. When the total of the acid value and the hydroxyl value exceeds 200 mgKOH / g, synthesis of the resin tends to be difficult, and the water resistance and workability of the resin film tend to be insufficient. On the other hand, if the total of the acid value and the hydroxyl value is less than 50 mgKOH / g, the adhesion after the processing such as coating, printing, vapor deposition, etc. on the easy-adhesion layer intended by the present invention is likely to be impaired. Such adhesion after hot water treatment is likely to be greatly impaired. The total valence of the acid value and the hydroxyl value of the polyester resin can be adjusted to a desired range by, for example, the amount of copolymerization of a trivalent or higher polyvalent carboxylic acid component and a trivalent or higher polyhydric alcohol component.

  In the easily adhesive film of the present invention, the acid value of the polyester resin forming the coating film needs to be 20 to 60 mgKOH / g, preferably 25 to 50 mgKOH / g, and more preferably 30 to 40 mgKOH / g. When the acid value exceeds 60 mgKOH / g, the water resistance and workability of the resin film tend to be insufficient. On the other hand, when the acid value is less than 20 mgKOH / g, the carboxylic acid concentration in the coating film decreases, the carboxylic acid concentration on the surface of the coating film relatively decreases, and it is difficult to obtain a desired value described later. Become. The acid value of the polyester resin can be adjusted to a desired range by, for example, the copolymerization amount of a trivalent or higher polyvalent carboxylic acid component.

  In the easy-adhesive film of the present invention, the hydroxyl value of the polyester resin forming the coating film needs to be 30 to 150 mgKOH / g, preferably 50 to 130 mgKOH / g, and more preferably 60 to 100 mgKOH / g. When the hydroxyl value exceeds 150 mgKOH / g, the water resistance and processability of the resin film tend to be insufficient, and the synthesis of the resin becomes difficult. On the other hand, when the hydroxyl value is less than 30 mgKOH / g, the hydroxyl group terminal concentration in the coating film is lowered, so that the surface hydroxyl group concentration of the coating film is relatively lowered, and it becomes difficult to obtain a desired value to be described later. The hydroxyl value of the polyester resin can be adjusted to a desired range by, for example, the copolymerization amount of a trihydric or higher polyhydric alcohol component.

  In the easy-adhesive film of the present invention, the polyester resin forming the coating film satisfies the above-described ranges of acid value and hydroxyl value, and has a ratio of hydroxyl value to acid value (hydroxyl value / acid value) of 2.0 to 5. 0.0, more preferably 2.5 to 4.5, and most preferably 3.0 to 4.0. When the ratio of the hydroxyl value to the acid value is less than 2.0, the adhesion after processing such as coating, printing, and vapor deposition on the easy-adhesion layer is likely to be impaired, and in particular, the adhesion after hot water treatment such as boiling and retort. Is easily damaged. Further, when the ratio of the hydroxyl value to the acid value is 5.0 or more, it is difficult to control the polymerization of the polyester resin.

The glass transition point of the polyester resin is not particularly limited, but is preferably 20 ° C. or higher and more preferably 30 ° C. or higher in consideration of film blocking and the like.
In the easy-adhesive film of the present invention, the thickness of the coating film needs to be 0.001 to 0.5 μm, preferably 0.005 to 0.1 μm, and more preferably 0.01 to 0.00. 05 μm. When the coating film is less than 0.001 μm or exceeds 0.5 μm, the adhesiveness of the easy-adhesive film of the present invention, particularly the adhesiveness after hot water treatment such as boil / retort treatment, is lowered. Furthermore, if the coating film is too thick, it is economically inefficient and the appearance of the coating film may be impaired.

  The surface carboxylic acid concentration of the coating film formed on the base film is preferably 0.005 or more, more preferably from 0.010 to 0.200. If it is less than 0.005, the adhesiveness intended by the present invention, particularly the adhesiveness after hot water treatment such as boil / retort treatment, tends to be lowered.

  In order to set the surface carboxylic acid concentration of the coating film to 0.005 or more, for example, in addition to the method using the acid value resin specified in the present invention as the polyester resin, the coating film after coating and drying is corona-coated. For example, a method of applying processing.

  The surface hydroxyl group concentration of the coating film formed on the substrate film is preferably 0.005 or more, more preferably 0.020 to 0.300. If it is less than 0.005, the adhesiveness intended by the present invention, particularly the adhesiveness after hot water treatment such as boil / retort treatment, tends to be lowered.

  In order to make the surface hydroxyl group concentration of the coating film 0.005 or more, for example, in addition to the method using the hydroxyl value resin defined in the present invention as the polyester resin, the coating film after coating and drying is subjected to corona treatment. The method of applying is mentioned.

  The surface primary amine concentration of the coating film is preferably 0.0001 or less. When the primary amine concentration exceeds 0.0001, the target adhesiveness of the present invention, particularly the adhesiveness after hot water treatment such as boil / retort treatment, tends to decrease.

  In order to set the amine concentration on the surface of the coating film within a predetermined range, it may be mentioned that no compound or resin having amines at the terminal and side chains is used in the coating film. Specific examples of compounds and resins having amines at the terminal and side chains include urea compounds, melamine compounds, acrylamide compounds, polyamide compounds, methylolated products thereof, methylmethylolated products, and the like.

  In the easy-adhesive film of the present invention, the coating film needs to contain substantially no cross-linking agent component. In the present invention, “substantially free of a crosslinking agent component” means that the content of the crosslinking agent component is 0.1% by mass or less including 0. It is highly preferred that it is zero. However, it is possible to contain a very small amount not exceeding 0.1 mass% at the maximum. Examples of the crosslinking agent that needs to be substantially not included include isocyanate compounds, melamine compounds, urea compounds, epoxy compounds, carbodiimide compounds, oxazoline compounds, and polyethyleneimine compounds. As will be described later, the coating film is preferably formed by coating an aqueous coating material containing a polyester resin as a main component on a base film. It is known that the above-mentioned crosslinking agent effectively crosslinks the polyester resin and imparts water resistance and adhesion to the coating film under the condition of reacting directly with the polyester resin. However, when blended into an aqueous coating agent, the crosslinking agent reacts with water in the coating agent or reacts with the crosslinking agent, whereby the adhesion and water resistance of the coating film tend to be impaired. Such a tendency is remarkable when a melamine crosslinking agent and an isocyanate crosslinking agent which may have an amine terminal structure after the crosslinking reaction are used among the crosslinking agents. For this reason, it is preferable not to use especially a melamine crosslinking agent and an isocyanate crosslinking agent among the said crosslinking agents.

Moreover, it is not necessary to use a foraldehyde generating material such as a melamine compound by substantially not containing a crosslinking agent component. For this reason, it can consider an environment.
The number average molecular weight of the polyester resin is preferably 500 or more and 7000 or less, more preferably 1000 or more and 6000 or less, and particularly preferably 2000 or more and 5000 or less. When the number average molecular weight is less than 500, the processability of the resin film tends to be lowered, particularly the solvent resistance is remarkably lowered, and the polyester may be dissolved by the organic solvent used at the time of printing or laminating, This may cause trouble during processing. On the other hand, when the number average molecular weight exceeds 7000, it is difficult to produce a polyester having the target acid value and hydroxyl group. Further, when the polyester resin is used as an aqueous dispersion, the viscosity increases and the stability of the aqueous dispersion tends to deteriorate. The number average molecular weight of the polyester resin can be determined by GPC (gel perem chromatography) analysis by the method described later.

  The polyester resin oligomer will be described. An oligomer is a low molecular weight component generated during the polymerization reaction of a polymer, and is obtained by polymerizing a finite number of monomers. In general polyester oligomers, a polyester monomer comprising a polybasic acid and a polyhydric alcohol constituting a polyester resin is polymerized by about 2 to 6 to form a chain or cyclic form. The molecular weight of the oligomer varies depending on the types of polybasic acid and polyhydric alcohol of the polyester resin raw material and the degree of polymerization of the target polyester resin, but the number average molecular weight is about 100 to 2,000. In the present invention, an oligomer of a polyester resin is defined as a component based on a peak that appears independently on a lower molecular weight side than the target polymer. The amount can be measured by an analysis method described later.

  In the present invention, the amount of oligomer contained in the polyester resin is required to be 2.0% by mass or less, more preferably 1.5% by mass or less, and most preferably 1.0% by mass or less. When the oligomer amount exceeds 2.0% by mass, the surface carboxyl concentration and the surface hydroxyl group concentration of the coating film tend to decrease. For this reason, the adhesiveness after performing the processing such as coating, printing, and vapor deposition on the coating film as the easy-adhesion layer is impaired, and particularly the adhesiveness after the hot water treatment such as boiling and retort is greatly impaired.

  The method for reducing the oligomer in the polyester resin is not particularly limited. For example, a method of removing the oligomer by contacting a polyester polymerized by a known method with a liquid organic solvent under normal temperature and normal pressure, or an emulsion prepared by making it aqueous. For example, and a method of removing precipitates generated with time by filtration or decantation as appropriate. In the present invention, a method is preferred in which the oligomer can be removed by a simple treatment with little burden on the environment and the emulsion is allowed to stand and the precipitate generated over time is removed as appropriate by filtration, decantation, or the like. This sediment is composed of cyclic oligomers such as terephthalic acid / ethylene glycol, terephthalic acid / neopentyl glycol, and isophthalic acid / neopentyl glycol. Such an oligomer has high crystallinity and does not have a terminal group, so that it easily precipitates in an emulsion and easily settles. The conditions for standing still are not particularly limited, but for example, a temperature of 5 to 25 ° C. and 10 to 1000 hours are appropriate.

  In the present invention, it is necessary that the acid value, hydroxyl value, and oligomer amount of the polyester resin used as the coating film are simultaneously within the above-mentioned ranges. In order to improve the adhesion of the coating film to the coating layer, it is important to improve the surface carboxylic acid concentration and the hydroxyl group concentration of the coating film. However, when the amount of oligomer contained in the polyester resin is large, the oligomer bleeds out to the surface of the coating film, so that the carboxylic acid concentration and the hydroxyl group concentration on the coating film surface are relatively lowered. For this reason, it is necessary not only to increase the acid value and hydroxyl value of the polyester resin constituting the coating film, but also to reduce the oligomer amount to a specific range.

  In the present invention, in order to form a coating film containing a polyester resin on a substrate film, the polyester resin is used as an aqueous dispersion, and an aqueous coating material containing the aqueous dispersion as a main component is used as a base material. Coating on a film is preferable because it is simple.

  A preferable aqueous dispersion of a polyester resin in the present invention is obtained by adding a basic compound to a polyester resin and dispersing it in water. The basic compound neutralizes the carboxylic acid in the polyester resin to produce a carboxyl anion, and the polyester resin is stably dispersed by the electric repulsion between the anions. As the basic compound to be added, when the amine component remains in the coating film after the resin film is formed, the adhesiveness intended by the present invention, in particular, the adhesiveness after hot water treatment such as boil and retort treatment is reduced. An organic amine having a boiling point of 250 ° C. or lower, preferably 160 ° C. or lower, or ammonia is preferable. Specific examples of organic amines preferably used 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-methoxypropylamine, monoethanolamine, Examples include diethanolamine, triethanolamine, morpholine, N-methylmorpholine, N-ethylmorpholine and the like. Of these, ammonia, triethylamine, and N, N-dimethylethanolamine are preferably used.

  The solid content concentration of the polyester resin in the aqueous coating material can be appropriately changed depending on the specifications of the coating apparatus and the drying / heating apparatus. However, a too dilute solution tends to cause a problem that it takes a long time in the drying process. On the other hand, if the concentration of the paint is too high, it is difficult to obtain a uniform paint, and problems in coating properties are likely to occur. From such a viewpoint, it is preferable that the solid content concentration of the polyester resin in the aqueous coating material is in the range of 3 to 30% by mass.

  In addition to the polyester resin as the main component, a surfactant may be added to the aqueous coating material in order to improve the coating property when the coating material is applied to the base film. Such a surfactant promotes the wetting of the aqueous coating material on the base film. Examples of the surfactant include anionic surfactants such as polyethylene alkyl phenyl ether, polyoxyethylene-fatty acid ester, glycerin fatty acid ester, fatty acid metal soap, alkyl sulfate, alkyl sulfonate, and alkyl sulfosuccinate, Nonionic surfactants such as acetylene glycol can be mentioned. The surfactant is preferably contained in the aqueous coating agent in an amount of 0.01 to 1% by mass. In addition, the surfactant is most preferably one that volatilizes at the heat treatment temperature in the film drying step because the surface carboxylic acid concentration and the surface hydroxyl group concentration are relatively lowered by bleeding out in the same manner as the oligomer. When remaining in the coating film, the amount is preferably in the range of 0.1 to 5% by mass.

  In order to impart blocking resistance to the easily adhesive film, inorganic or organic particles may be added to the aqueous coating material. Examples of inorganic particles include calcium carbonate, magnesium carbonate, calcium oxide, zinc oxide, magnesium oxide, silicon oxide, sodium silicate, aluminum hydroxide, iron oxide, zirconium oxide, barium sulfate, titanium oxide, and carbon black. Can be mentioned. Examples of the organic particles include an acrylic cross-linked polymer, a styrene cross-linked polymer, a phenol resin, a nylon resin, and a polyethylene wax. The particle diameter of the inorganic or organic particles is preferably 0.0001 to 5 μm, more preferably 0.01 to 1 μm. The addition amount is preferably 0 to 1.0% by mass in the aqueous coating material, and is preferably contained in the range of 0 to 10% by mass in the obtained coating film.

  Application | coating of the aqueous coating material to a base film can be performed in the arbitrary steps of the manufacturing process of a base film. However, it is preferably applied to the substrate film before the orientation crystallization is completed. The “base film before crystal orientation is completed” refers to an unstretched film, a uniaxially oriented film in which the unstretched film is oriented in either the longitudinal direction or the transverse direction. After applying the aqueous coating material to the base film, the base film is preferably stretched in at least one direction together with the coating film, and subjected to heat setting treatment. The stretching method may be appropriately changed depending on the properties of the thermoplastic resin to be used, but a tenter simultaneous biaxial stretching method, a sequential biaxial stretching method, or the like can be used.

  Although the method for apply | coating an aqueous coating material to a base film is not specifically limited, Ordinary methods, such as gravure roll coating, reverse roll coating, wire bar coating, and air knife coating, can be used.

  The easy-adhesive film of the present invention has excellent adhesion to various secondary processing agents such as paints and printing inks on the film surface, and also has excellent adhesion to a sealant film. The utility value as a base film for general industrial use is great. Moreover, since it has excellent adhesiveness after hot water treatment such as boil / retort treatment, it can be suitably used particularly in the field of packaging boil / retort food.

  Hereinafter, the present invention will be described in detail by way of examples. In the present invention, various physical property measurement methods and effect evaluation methods are as follows.

(1) Glass transition point (Tg) of polyester resin
A polyester resin 10 mg was used as a sample, and measurement was performed using a DSC (Differential Scanning Calorimetry) apparatus (DSC7, manufactured by PerkinElmer Co., Ltd.) at a temperature rising rate of 10 ° C./min. And the intermediate value of the temperature of two bending points derived from the glass transition in the obtained temperature rising curve was calculated | required, and this was made into the glass transition point (Tg).

(2) Acid value of polyester resin 1 g of polyester resin was dissolved in 50 ml of water / dioxane = 10/1 (volume ratio), titrated with KOH using cresol red as an indicator, and the amount of KOH consumed for neutralization. A value obtained by converting the number of mg per 1 g of the polyester resin was determined as an acid value.

(3) Hydroxyl value of polyester resin 3 g of polyester resin is precisely weighed, 0.6 ml of acetic anhydride and 50 ml of pyridine are added, and the mixture is stirred at room temperature for 48 hours, followed by addition of 5 ml of distilled water for further 6 By continuing stirring at room temperature for an hour, all acetic anhydride that was not used in the above reaction was also changed to acetic acid. Add 50 ml of dioxane to this solution and titrate with KOH using cresol red and thymol blue as an indicator. The amount of KOH consumed for neutralization (W ₁ ) and the amount of acetic anhydride initially charged is polyester. From the amount of KOH required for neutralization (calculated value: W ₀ ) when acetic acid is formed without reacting with the resin, the difference (W ₀ −W ₁ ) is expressed in mg of KOH. The value obtained by dividing this by the number of grams of the polyester resin was taken as the hydroxyl value.

(4) Number average molecular weight of polyester resin GPC analysis is performed using a liquid feeding unit LC-10ADvp type manufactured by Shimadzu Corporation and an ultraviolet-visible spectrophotometer (detection wavelength: 254 nm, solvent: tetrahydrofuran), and converted to polystyrene. The number average molecular weight was determined using GPC analysis software “CLASS-10” manufactured by Shimadzu Corporation.

(5) Oligomer amount of polyester resin The oligomer amount of the polyester resin was determined from the result of the molecular weight chart by the GPC analysis described above. That is, in the present invention, a molecular weight peak on the lower molecular weight side than a peak constituting the main molecular weight distribution of the polyester resin is defined as a molecular weight peak composed of an oligomer from each peak identified by the GPC analysis software, and these peaks The ratio of the area to the area of the entire chart was obtained. In addition, since the area represented by the molecular weight chart reflects the concentration of each component at the time of polystyrene conversion, the oligomer amount is expressed in mass%.

This will be specifically described with reference to FIG. FIG. 1 is a molecular weight chart in GPC analysis of a polyester resin used in Example 1 described later. In this chart, the main peak of the polyester resin appears at a peak time of 25.058 min, and the peak derived from the oligomer appears at 33.750 min. The peak appearing at 36.902 min is identified as the peak of tetrahydrofuran used as the solvent. In the present invention, the total area (S) of the polyester resin including oligomers in the molecular weight chart determined by GPC analysis and the polyester peak area (S) constituting the main molecular weight distribution determined by the vertical splitting method using the GPC analysis software. _{From 1} ), the oligomer amount was determined using the following equation.
Amount of oligomer [mass%] = (S−S ₁ ) / S × 100

(6) Composition analysis of polyester resin 10 mg of polyester resin was precisely weighed and placed in an NMR sample tube together with 0.5 ml of 1 mol / L sodium hydroxide solution (solvent: methanol / DMSO = 1/4 (volume ratio)), 120 ° C. Heated for 10 minutes. Thereafter, a small amount of CF ₃ COOD was added, and the transparent solution was subjected to ¹ H-NMR measurement using NMR JOEL LAMBDA300WB manufactured by JEOL.

(7) Surface carboxylic acid concentration, surface hydroxyl group concentration and surface primary amine concentration of coating film [Measurement conditions]
ESCA (X-ray photoelectron spectroscopy analyzer) manufactured by Shimadzu Corporation, model number: KRATOS AXIS-HSi was used, and measurement was performed under the following conditions.

X-ray source: Al Kα
X-ray output: 150W
Photoelectron extraction angle: 90 ° to sample surface
Binding energy: Shift correction with C1s spectrum as 285.0 eV [Method for measuring surface carboxylic acid concentration]
The film on which the coating film was formed was cut into an appropriate size, and COOH was chemically modified by a gas phase chemical modification method. Trifluoroethanol (TFE) was used for chemical modification. In a vial containing TFE, dicyclohexylcarbodiimide (DCC), and pyridine, the sample was subjected to a gas phase reaction without contact with the reagent. The reaction formula is as follows.

_{R-COOH + CF 3 CH 2} OH (TFE)
+ C ₆ H ₁₁ NCNC ₆ H ₁₁ (DCC)
→ R-COOCH ₂ CF ₃ + C ₆ H ₁₁ NHCONHC ₆ H ₁₁
The reaction rate γ of the above reaction was calculated from the ratio of the CF ₃ structure to the COO structure in the C1s spectrum of the polyacrylic acid (PAA) standard sample reacted in the vial at the same time as the film. Further, C ₆ H ₁₁ NHCONHC ₆ H _{11 on the} right side of the reaction formula may remain on the sample surface, and the residual ratio m was calculated from the O1s spectrum after chemical modification of the PAA standard sample. That is, ₂ oxygen atoms of R-COOCH ₂ CF ₃ after reaction and 1 oxygen atom of C ₆ H ₁₁ NHCONHC ₆ H ₁₁ were distinguished by waveform separation, and calculated by the following formula.

m = 2 [O _NH-CO-NH ] / ([O _{C = O} ] + [O _C-O ])
_{(Molecular: C 6 H 11 NHCONHC 6 H} 11 from oxygen, denominator: R-COOCH ₂ CF ₃ from the oxygen)
The surface carboxylic acid concentration was calculated from the following equation as the ratio of COOH to total carbon ([COOH] / [C]).

[COOH] / [C]
= ([F1s] / 3) / (([C1s] -2 [F1s] / 3-13m [F1s] / 3) γ)
= [F1s] / ((3 [C1s] -2 [F1s] 3-13m [F1s]) γ)
In the above equation, [C1s] and [F1s] are atomic% of C and F obtained from the C1s and F1s signals, respectively.

[Measurement method of surface hydroxyl group concentration]
Chemical modification of the OH group was performed using trifluoroacetic anhydride (TFAA). N ₂ The samples were placed and TFAA to substituted vial was gas phase reaction in a non-contact manner. The reaction formula is as follows.

R—OH + (CF ₃ CO) ₂ O (TFAA)
→ R-OCOCF ₃ + CF ₃ COOH
The reaction rate of chemical modification can be calculated by the ratio of CF ₃ structure to C—O structure in the C1s spectrum of polyvinyl alcohol (PVA) placed in the reaction vessel at the same time as the sample. The ratio ([OH] / [C]) was calculated from the following equation.

[OH] / [C] = ([F1s] / 3) / ([C1s] -2 [F1s] / 3)
= [F1s] / (3 [C1s] -2 [F1s])
In the above equation, [C1s] and [F1s] are atomic% of C and F obtained from the C1s and F1s signals, respectively.

[Measurement method of surface primary amine concentration]
Chemical modification of the NH ₂ group was performed using pentafluorobenzaldehyde (PFB). Specifically, the sample was subjected to a gas phase reaction in a non-contact manner in a vial containing PFB. The reaction formula is as follows.

_{R-NH 2 + C 6 H} 5 CHO (PFB) → R-N = CHC 6 F 5
The surface primary amine concentration is calculated as a ratio of NH _{2 to} total carbon ([NH ₂ ] / [C]) as follows. γ is a reaction rate and can be calculated from the element ratio of N and F of 4,4′-diaminodiphenyl ether (DADPE) reacted at the same time as the sample (γ = [F1s] / 5 [N1s]).

[NH ₂ ] / [C]
= ([F1s] / 5) / (([C1s] -7 [F1s] / 5) γ)
= [F1s] / ((5 [C1s] -7 [F1s] / 5) γ)

(8) Laminate strength evaluation of printing film First, printing was performed on the easy-adhesion coating film of the easy-adhesion film with a gravure roll. Two types of printing were performed: single color printing and multicolor printing. Single color printing was performed with white ink, and multicolor printing was performed by printing indigo ink after printing white ink. After printing, it was dry laminated with an unstretched polypropylene film using a dry laminate adhesive for retort applications. Adhesive recommended aging was performed to obtain a laminate film.

  The laminate strength is measured by taking a test piece having a width of 15 mm from the laminate film, peeling off the interface between the polypropylene film and the coating film of the easy-adhesion film from the end of the test piece in an atmosphere of 20 ° C. and 65% Rh, This was done by measuring the peel strength. The laminate strength was also measured when the laminate film was further retorted (120 ° C., 1.8 atm for 30 minutes).

  In this peeling test, assuming the actual use of the packaging material, the first laminate strength assuming the case where the content is only solid, and the case where the content is filled with liquid, peeling The second laminate strength with water on the interface was measured. Furthermore, the adhesiveness of an easily-adhesive film-ink was evaluated by observing the peeling interface of the film after peeling.

The evaluation criteria are as follows.
Evaluation 3: More than 50% (area ratio, the same applies hereinafter) of ink remains on the easy-adhesion coating film side.
Evaluation 2: The ink remains in the range of 25% or more and less than 50% on the easily adhesive coating film side.

Evaluation 1: The ink remains in the range of 1% or more and less than 25% on the easily adhesive coating film side.
Evaluation 0: Less than 1% of ink remains on the easily adhesive coating film side.
Practically, if an easily adhesive polyester film has a laminate strength of 1 N / cm or more, and an easily adhesive nylon film has a laminate strength of 1.5 N / cm or more, it can be used without any problem. Moreover, it is more preferable that it is "Evaluation 1" or more in which ink substantially remains on the easily adhesive coating film side.

(9) Laminate strength evaluation of vapor deposition film Using an electron beam heating vapor deposition machine, Al is vapor-deposited on the easy adhesion film of an easy adhesion film so that vapor deposition thickness may be 40-50 nm (400-500 angstrom). did. Then, it was dry laminated with an unstretched low density polyethylene film using a dry laminate adhesive for general boil use. The laminated film was subjected to aging recommended by an adhesive to obtain a laminated film.

  For the measurement of the laminate strength, a test piece having a width of 15 mm was taken from the laminate film, and the tensile tester (AGS-100B type, manufactured by Shimadzu Corporation) was used at 20 ° C. and 65% Rh atmosphere by the T peel method. It was performed by peeling the film interface from the end of the test piece under the condition of a tensile speed of 300 mm / min. In this peel test, the normal laminate strength was measured assuming that the contents were only solid, assuming the actual use of the packaging material. Furthermore, the adhesiveness of an easily-adhesive film-deposition layer was evaluated by observing the peeling interface of the film after peeling.

The evaluation criteria are as follows.
Evaluation 3: More than 50% (area ratio, the same applies hereinafter) of the deposited layer remains on the easy-adhesive coating film side.
Evaluation 2: The vapor deposition layer remains in the range of 25% or more and less than 50% on the easy adhesion coating film side.

Evaluation 1: The vapor deposition layer remains in the range of 1% or more and less than 25% on the easily adhesive coating film side.
Evaluation 0: Less than 1% of the deposited layer remains on the easy-adhesive coating film side.
Practically, if the laminate strength is 1 N / cm or more in the easily adhesive polyester film and the laminate strength is 1.5 N / cm or more in the easily adhesive nylon film, it can be used without any problem. Moreover, it is more preferable that it is "Evaluation 1" or more in which a vapor deposition layer remains on the easily adhesive coating film side.

Example 1
[Production of polyester resin]
A polyvalent carboxylic acid raw material comprising terephthalic acid (TPA) 58 mol%, sebacic acid (SEA) 4 mol%, naphthalenedicarboxylic acid (NDCA) 32 mol%, trimellitic acid (TMA) 6 mol%, and ethylene glycol (EG) ) A polyhydric alcohol raw material consisting of 35 mol%, 1,4-butanediol (BD) 29 mol%, and neopentyl glycol (NPG) 36 mol% was used. (Polyhydric alcohol raw material) / (Polyhydric carboxylic acid raw material) = 1.13 (molar ratio) was charged into a reaction can, and tetrabutyl titanate as a catalyst was 0 with respect to the number of moles of all polyhydric carboxylic acid raw materials 0.04 mol% was added. And it heated up to temperature 240 degreeC in 4 hours in nitrogen atmosphere. At that time, generated methanol and water were distilled off. Thereafter, the pressure in the system was gradually reduced and polycondensation was performed for 2 hours. Furthermore, the inside of the system was cooled to 200 ° C. Thereafter, 5 mol% of trimellitic anhydride (TMA) was added to the polyvalent carboxylic acid raw material already used, and 5 mol% of trimethylolpropane (TMP) was added to the polyhydric alcohol raw material already used. For 2 hours. Thus, terephthalic acid (TPA) / sebacic acid (SEA) / naphthalenedicarboxylic acid (NDCA) / trimellitic acid (TMA) / ethylene glycol (EG) / 1,4-butanediol (BD) / neopentyl glycol (NPG) ) / Trimethylolpropane (TMP) = 55/4/30/11/34/27/35/4 (molar ratio) polyester resin was obtained.

[Water-based polyester resin]
300 g of the above polyester resin, 100 g of ethylene glycol monobutyl ether, 90.3 g of a 30% aqueous ammonia solution, and 509.7 g of distilled water, a stirrer equipped with a jacketed 2 liter glass container that can be sealed (specialization) TK Robotics manufactured by Kogyo Co., Ltd.). And it stirred with the rotational speed of the stirring blade (homodisper) set to 7,000 rpm. Next, hot water was passed through the jacket of the stirrer, and the system temperature was maintained at 73 to 75 ° C, followed by stirring for 60 minutes. Thereafter, cold water was allowed to flow through the jacket, and the stirring blade was cooled to room temperature (about 25 ° C.) while stirring at a rotational speed of 5,000 rpm. And it filtered with the 300 mesh stainless steel filter, and obtained polyester resin aqueous dispersion with a solid content concentration of 25 mass%. About the obtained polyester resin aqueous dispersion, when the oligomer amount of the polyester resin was measured using GPC, the amount was 1.32 mass%. For this reason, the oligomer removal process was not performed.

[Preparation of water-based paint]
0.1 part by mass of 100 parts by mass of polyester resin solid content of “Olfin E1004 (manufactured by Nissin Chemical Industry Co., Ltd.)” which is an acetylene glycol surfactant is added to the aqueous polyester resin dispersion made water-based by the above method. And diluted with water as appropriate. As a result, an aqueous coating composition having a composition of a polyester resin solid content of 5% by mass and a surfactant of 0.005% by mass was prepared.

[Manufacture of easily adhesive polyester film]
Relative viscosity 1.38 (phenol: ethane tetrachloride = 1: 1 (mass ratio) mixture containing 0.1% by mass of silica having an average particle size of 1.0 μm as a solvent, temperature 20 ° C., concentration 0.5 g / 100 ml Polyethylene terephthalate (PET) (measured under the conditions), and this was 280 ° C., discharge amount 500 g / mm from an extruder equipped with a T die (75 mm diameter, L / D = 45 slow compression type single screw). Extruded into a sheet under the condition of minutes. Then, this was closely_contact | adhered on the casting roll adjusted to the surface temperature of 18 degreeC, and rapidly cooled, and the 120-micrometer-thick unstretched film was obtained. This unstretched film was heated to 90 ° C. and stretched 3.3 times in the longitudinal direction to obtain a uniaxially stretched film. The above aqueous coating composition was applied to this film. The coated uniaxially stretched film is guided to the preheating zone while being gripped with a clip, dried at 90 ° C, continuously stretched 3.3 times in the width direction in a heating zone at 120 ° C, and further heated at 235 ° C. To obtain an easy-adhesion polyester film in which crystal orientation was completed. At this time, the base polyester film had a thickness of 12 μm, and the coating film had a thickness of 0.04 μm. The surface carboxylic acid concentration, surface hydroxyl group concentration, and surface primary amine concentration of the coating film of this easy-adhesion film were measured.

[Preparation of printed laminate film]
Printing was carried out on the coating surface of the easy-adhesion film by direct gravure printing using polyurethane-based ink (Toyo Ink Manufacture Finestar R39 Indigo / R631 White). Thereafter, heat treatment was performed at 80 ° C. for about 10 seconds. Next, a polyurethane-based adhesive (Dick Dry LX500 / KW75 manufactured by Dainippon Ink & Chemicals, Inc.) was applied to the ink surface of the film and heat-treated at 80 ° C. Thereafter, an unstretched polypropylene film (RXC-21 manufactured by Tosero Co., Ltd., thickness 50 μm) was dry-laminated at a nip pressure of 490 kPa on a metal roll heated to 80 ° C. to obtain a laminate film. The thickness of each layer after dry lamination was 1 μm for both the indigo / white ink layer and 2 μm for the adhesive layer. Next, the laminate strength before and after the retort treatment of this film was measured.

[Creation of vapor-deposited laminate film]
On the coating surface of the easy-adhesion film, Al was vapor-deposited using an electron beam heating vapor deposition machine so that the vapor deposition thickness was 40 to 50 nm (400 to 500 angstroms) as described above. Thereafter, a polyurethane adhesive (Dick Dry LX401 / SP60 manufactured by Dainippon Ink & Chemicals, Inc.) was applied and heat-treated at 80 ° C. Next, an unstretched low-density polyethylene film (manufactured by Tosero Co., Ltd., T.U.X FCD, thickness 50 μm) was dry-laminated at a nip pressure of 490 kPa on a metal roll heated to 80 ° C., and then at 40 ° C. for 7 days. An aging treatment was performed to obtain a laminate film. The thickness of the adhesive layer after dry lamination was 2 μm.

(Example 2)
By changing the raw material charging conditions in Example 1, terephthalic acid / sebacic acid / 2,6-naphthalenedicarboxylic acid / trimellitic acid / ethylene glycol / 1,4-butanediol / neopentyl glycol / trimethylolpropane = 53 A polyester resin was synthesized to have a composition of / 4/30/12/35/25/34/6 (molar ratio). Then, this polyester resin was made aqueous in the same manner as in Example 1. When the oligomer amount of this polyester resin was measured using GPC, the amount was 0.85 mass%. For this reason, the oligomer removal process was not performed. Further, an aqueous coating agent was obtained in the same manner as in Example 1, and an easy-adhesive polyester film was obtained in the same manner as in Example 1 using this.

(Example 3)
By changing the raw material charging conditions in Example 1, terephthalic acid / 2,6-naphthalenedicarboxylic acid / trimellitic acid / ethylene glycol / 1,4-butanediol / neopentyl glycol / trimethylolpropane = 28/49 / A polyester resin was synthesized so as to have a composition of 23/35/36/21/8 (molar ratio). Then, this polyester resin was made aqueous in the same manner as in Example 1. When the oligomer amount of this polyester resin was measured using GPC, the amount was 1.22 mass%. For this reason, the oligomer removal process was not performed. Further, an aqueous coating agent was obtained in the same manner as in Example 1, and an easy-adhesive polyester film was obtained in the same manner as in Example 1 using this.

Example 4
By changing the raw material charging conditions in Example 1, terephthalic acid / 2,6-naphthalenedicarboxylic acid / trimellitic acid / ethylene glycol / 1,4-butanediol / neopentyl glycol / trimethylolpropane = 17/64 / A polyester resin was synthesized so as to have a composition of 19/51/12/19/18 (molar ratio). Then, this polyester resin was made aqueous in the same manner as in Example 1. When the oligomer amount of this polyester resin was measured using GPC, the amount was 0.56 mass%. For this reason, the oligomer removal process was not performed. Further, an aqueous coating agent was obtained in the same manner as in Example 1, and an easy-adhesive polyester film was obtained in the same manner as in Example 1 using this.

(Example 5)
By changing the raw material charging conditions in Example 1, terephthalic acid / isophthalic acid (IPA) / sebacic acid / trimellitic acid / ethylene glycol / 1,4-butanediol / neopentyl glycol = 61/17/7/15 A polyester resin was synthesized so as to have a composition of / 24/32/44 (molar ratio). Then, this polyester resin was made aqueous in the same manner as in Example 1. When the amount of oligomers of this polyester resin aqueous dispersion was measured using GPC, the amount was 3.58 mass%. For this reason, the standing was continued until the amount of oligomer in the aqueous dispersion of the polyester resin became 2% by mass or less. When the standing time was 432 hours, the amount of oligomer was 0.40% by mass, and thus an aqueous coating composition was prepared using this aqueous dispersion. By using this aqueous coating material, an easily adhesive polyester film was obtained in the same manner as in Example 1.

(Example 6)
By changing the raw material charging conditions in Example 1, terephthalic acid / 2,6-naphthalenedicarboxylic acid / trimellitic acid / ethylene glycol / 1,4-butanediol / neopentyl glycol = 18/71/11/63 / A polyester resin was synthesized so as to have a composition of 13/24 (molar ratio). Then, this polyester resin was made aqueous in the same manner as in Example 1. Furthermore, the oligomer was removed in the same manner as in Example 5 to obtain an aqueous coating composition containing a predetermined amount of polyester. By using this aqueous coating material, an easily adhesive polyester film was obtained in the same manner as in Example 1.

(Example 7)
By changing the raw material charging conditions in Example 1, terephthalic acid / 2,6-naphthalenedicarboxylic acid / trimellitic acid / ethylene glycol / 1,4-butanediol / neopentyl glycol = 28/49/23/38 / A polyester resin was synthesized by changing the composition to 38/24 (molar ratio). Then, this polyester resin was made aqueous in the same manner as in Example 1. Furthermore, the oligomer was removed by the same method as in Example 5 to obtain an aqueous coating composition containing a predetermined amount of polyester. By using this aqueous coating material, an easily adhesive polyester film was obtained in the same manner as in Example 1.

(Example 8)
By changing the raw material charging conditions in Example 1, terephthalic acid / isophthalic acid / sebacic acid / trimellitic acid / ethylene glycol / 1,4-butanediol / neopentyl glycol = 59/16/7/18/32 / A polyester resin was synthesized so as to have a composition of 28/40 (molar ratio). Then, this polyester resin was made aqueous in the same manner as in Example 1. Furthermore, the oligomer was removed by the same method as in Example 5 to obtain an aqueous coating composition containing a predetermined amount of polyester. By using this aqueous coating material, an easily adhesive polyester film was obtained in the same manner as in Example 1.

Example 9
By changing the raw material charging conditions in Example 1, terephthalic acid / sebacic acid / 2,6-naphthalenedicarboxylic acid / trimellitic acid / ethylene glycol / 1,4-butanediol / neopentyl glycol = 56/4/30 A polyester resin was synthesized so as to have a composition of / 10/36/27/37 (molar ratio). Then, this polyester resin was made aqueous in the same manner as in Example 1. Furthermore, the oligomer was removed by the same method as in Example 5 to obtain an aqueous coating composition containing a predetermined amount of polyester. By using this aqueous coating material, an easily adhesive polyester film was obtained in the same manner as in Example 1.

(Examples 10 to 18)
The base film of the easily adhesive film in Examples 1 to 9 was changed from a polyester film to a nylon film (ON). The manufacturing method of the easily bonding nylon film by it is shown below.

  Using nylon 6 having a relative viscosity of 3.03 containing 0.1% by mass of silica having an average particle size of 1.0 μm (measured under the conditions of a temperature of 25 ° C. and a concentration of 1 g / 100 ml using 96% by mass sulfuric acid as a solvent) Extruded into a sheet from an extruder (75 mm diameter, L / D = 45 slow compression type single screw) equipped with a T die under the conditions of 260 ° C. and discharge rate of 500 g / min. Subsequently, this was brought into close contact with a casting roll adjusted to a surface temperature of 18 ° C. and rapidly cooled to obtain an unstretched polyamide film having a thickness of 150 μm. Next, this unstretched film was led to a water tank and adjusted to a water absorption rate of 4.0%. Then, after apply | coating each aqueous coating agent used in Examples 1-9 to the water-absorbed unstretched film, it dried at 60 degreeC with the dryer. Next, the unstretched film coated with the aqueous coating material is guided to a simultaneous biaxial stretching machine set at a preheating temperature of 225 ° C. and a stretching temperature of 195 ° C., and simultaneously stretched to 3.0 times in length and 3.3 times in width. The film was axially stretched and further heat-treated at 205 ° C. As a result, a biaxially stretchable and easily adhesive nylon film having a thickness of about 15 μm was obtained. The thickness of the coating film at this time was 0.04 μm. The same measurement test as the easily adhesive polyester film of Examples 1-9 was done with respect to this easily adhesive nylon film.

(Comparative Examples 1-5)
The oligomer resin removal process was not performed about the polyester resin aqueous dispersion used for Examples 5-9. The aqueous coating material thus obtained was coated on the polyester film in the same manner as in Example 1 to prepare an easily adhesive polyester film.

(Comparative Example 6)
By changing the raw material charging conditions in Example 1, terephthalic acid / isophthalic acid / adipic acid (ADA) / trimellitic acid / ethylene glycol / neopentyl glycol = 55/30/13/2/50/50 (molar ratio) A polyester resin was synthesized so as to have a composition of Then, this polyester resin was made aqueous in the same manner as in Example 1. Furthermore, the oligomer was removed by the same method as in Example 5 to obtain an aqueous coating composition containing a predetermined amount of polyester. By using this aqueous coating material, an easily adhesive polyester film was obtained in the same manner as in Example 1.

(Comparative Example 7)
The polyester resin aqueous dispersion used in Comparative Example 6 was not subjected to the oligomer removal step. The aqueous coating material thus obtained was coated on the polyester film in the same manner as in Example 1 to prepare an easily adhesive polyester film.

(Comparative Example 8)
15 parts by mass of Adeka Resin EM-0103 (manufactured by Adeka Co., Ltd .: solid content concentration: 70% by mass), which is a methylolated melamine-based crosslinking agent, was added to the aqueous coating agent used in Example 5. Added. Thereafter, a liquid prepared by stirring for 2 hours using a homomixer was used as an aqueous coating composition. Otherwise, an easy-adhesion polyester film was produced in the same manner as in Example 1.

(Comparative Example 9)
The crosslinking agent added to the aqueous coating agent was changed to an isocyanate-based crosslinking agent AQ-100 (manufactured by Nippon Polyurethane Co., Ltd .: solid content concentration 100% by mass). Otherwise, an easily adhesive polyester film was prepared in the same manner as in Comparative Example 8.

(Comparative Example 10)
By changing the raw material charging conditions in Example 1, terephthalic acid / isophthalic acid / trimellitic acid / 5-sulfoisophthalic acid (SIP) / ethylene glycol / diethylene glycol (DEG) = 61/31/3/5/23 / A polyester resin was synthesized so as to have a composition of 77 (molar ratio). Then, this polyester resin was made aqueous in the same manner as in Example 1. Further, the oligomer was removed in the same manner as in Example 1 to obtain an aqueous coating material containing a predetermined amount of polyester. An easily-adhesive polyester film was obtained using this aqueous coating material.

(Comparative Example 11)
By changing the raw material charging conditions in Example 1, terephthalic acid / isophthalic acid / trimellitic acid / 5-sulfoisophthalic acid / ethylene glycol / diethylene glycol = 61/33/1/5/52/48 (molar ratio) A polyester resin was synthesized so as to have a composition. Then, this polyester resin was made aqueous in the same manner as in Example 1. Furthermore, the oligomer was removed by the same method as in Example 5 to obtain an aqueous coating composition containing a predetermined amount of polyester. An easily-adhesive polyester film was obtained using this aqueous coating material.

(Comparative Example 12)
An easy-adhesive polyester film was prepared in the same manner as in Example 5 except that the thickness of the easy-adhesive coating film was 1 μm.

(Comparative Examples 13-24)
The base film of the easily adhesive polyester film was changed to the same nylon film as used in Examples 10-18. Otherwise, an easy-adhesive nylon film was prepared in the same manner as in Comparative Examples 1-12.

  Table 1 shows the compositions and some of the characteristics of the water-based coatings of the examples and comparative examples.

  Table 2 shows the balance of the properties of the water-based coating and the properties of the easy-adhesive film for each of the examples and comparative examples.

  Table 3 shows the characteristics of the printed laminate film and the characteristics of the vapor-deposited laminate film for each example and comparative example.

表１〜３の結果からわかるように、各実施例では、酸価、水酸基価、酸価と水酸基価の合計価数が本発明で規定する範囲を満たし、かつオリゴマー量が２．０質量％以下であるポリエステル樹脂を、塗膜として、本発明で規定する厚み範囲に形成することにより、レトルト処理前後および蒸着処理後も、ポリエステルフィルムにおいて１Ｎ／ｃｍ以上、ナイロンフィルムにおいて１．５Ｎ／ｃｍ以上のラミネート強力を有する易接着フィルムを作製できた。上記ラミネート強力は、界面評価が０の例においても達成されていた。

As can be seen from the results of Tables 1 to 3, in each example, the acid value, the hydroxyl value, and the total valence of the acid value and the hydroxyl value satisfy the range defined in the present invention, and the oligomer amount is 2.0% by mass. By forming the following polyester resin as a coating film in the thickness range defined in the present invention, the polyester film is 1 N / cm or more in the polyester film and 1.5 N / cm or more in the nylon film even before and after the retort treatment and after the vapor deposition treatment. An easy-adhesive film having a laminate strength of 1 was able to be produced. The laminate strength was achieved even in an example where the interface evaluation was zero.

  Moreover, even if the type of printing was changed, the laminate strength in the above-mentioned numerical range was practically sufficient in both normal and wet conditions. In particular, when a polyester resin containing trimethylolpropane (TMP) was used in the resin composition, the interface evaluation and the laminate strength were good.

On the other hand, each comparative example has the following problems.
In Comparative Examples 1 to 5 and 13 to 17, the total valency of the acid value and the hydroxyl value of the polyester resin satisfies the range specified by the present invention, but the range of the oligomer amount contained in the polyester resin specified by the present invention. It was over. For this reason, the lamination strength at the time of watering before the retort treatment and the normal state after the retort treatment and the laminate strength at the time of watering were lowered.

  In Comparative Examples 6 and 18, the amount of oligomer contained in the polyester resin satisfied the range specified in the present invention, but the total valence of the acid value and hydroxyl value of the polyester resin was less than the range specified in the present invention. . For this reason, the lamination strength at the normal state after retorting and watering decreased.

  In Comparative Examples 7 and 19, the acid value of the aqueous polyester resin, the total valence of the hydroxyl value, and the amount of oligomer in the aqueous polyester resin were outside the range defined in the present invention. For this reason, the laminate strength at the time of watering before the retort treatment and the laminate strength at the time of normal and watering after the retort treatment were lowered.

  In Comparative Examples 8, 9 and 20, 21, the addition of a melamine cross-linking agent and an isocyanate cross-linking agent in the aqueous coating material provided high lamination strength and vapor deposition suitability before retorting. However, since the coating film contained a crosslinking agent, the concentration of the surface primary amine was increased, and the normal state after retorting and the laminate strength during watering were reduced.

  In Comparative Examples 10, 11 and 22, 23, the amount of oligomer in the aqueous polyester resin satisfied the range specified in the present invention, but the acid value, hydroxyl value, and total number of acid values and hydroxyl values in the aqueous polyester resin. However, none of these satisfied the range defined in the present invention. For this reason, the surface carboxylic acid density | concentration in an easily bonding coating film fell, and the laminate strength at the time of watering before a retort process and the laminate strength at the time of normal after a retort process and watering fell.

  In Comparative Examples 12 and 24, since the film thickness of the easy-adhesion coating film exceeded the range specified in the present invention, the laminate strength after the retort treatment was lowered.

Is a diagram showing an area _{S 1} in the GPC analysis of the polyester resin.

Claims (7)

  On at least one surface of the base film, a coating film containing a polyester resin and having a crosslinking agent component content of 0 and 0.1% by mass or less is formed, and the total value of the acid value and hydroxyl value of the polyester resin The number is 50 to 200 mg KOH / g, the acid value is 20 to 60 mg KOH / g, the hydroxyl value is 30 to 150 mg KOH / g, and the amount of oligomers contained in the polyester is 2.0% by mass or less. An easily adhesive film having a thickness of 0.001 to 0.5 μm.   The surface carboxylic acid concentration and the surface hydroxyl group concentration of the coating film are both 0.005 or more, and the surface primary amine concentration of the coating film is 0.0001 or less. Adhesive film.   The easily adhesive film according to claim 1, wherein the crosslinking agent component is a melamine compound.   The easily adhesive film according to claim 1, wherein the ratio of hydroxyl value to hydroxyl value (hydroxyl value / acid value) of the polyester resin is 2.0 to 5.0.   The easily adhesive film according to claim 1, wherein the polyester resin contains both a trivalent or higher polyvalent carboxylic acid component and a trivalent or higher polyhydric alcohol component.   6. The easily adhesive film according to claim 5, wherein the trivalent or higher polyvalent carboxylic acid component is trimellitic acid, and the trivalent or higher polyhydric alcohol component is trimethylolpropane.   In producing the easy-adhesion film according to claim 1, at least one side of the base film before orientation crystallization has a polyester resin as a main component and the content of the cross-linking agent component is 0 and is 0.1% by mass or less. A coating film is formed by applying an aqueous coating material, and then the base film is oriented and crystallized by stretching the base film together with the paint film in at least one direction and heat-treating the base film. The manufacturing method of an easily adhesive film.

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