JP4329013B2 - Easy-adhesive polyester film and method for producing the same - Google Patents

Description

  The present invention relates to an easily adhesive plastic film and a method for producing the same. More particularly, the present invention relates to a highly adhesive plastic film having excellent adhesion to a vapor deposited metal layer, particularly excellent in water vapor barrier properties after vapor deposition, and provided to packaging materials and industrial materials, and a method for producing the same.

  Polyester films are excellent in mechanical properties, heat resistance and transparency, and are widely used as industrial applications and food packaging films. However, the polyester film alone lacks so-called gas barrier properties such as oxygen and water vapor barrier properties, which is one of the extremely important performances for food packaging materials. Therefore, vapor deposition of metals such as aluminum or metal oxides on the film surface, or forming a so-called gas barrier layer, improves the gas barrier property and further enhances food storage stability.

  The polyester film has excellent properties, but its surface is highly oriented and crystallized, and the surface is highly cohesive and generally has low adhesion. For this reason, surface modification is achieved by physical treatment methods such as corona discharge treatment and plasma treatment, and chemical treatment methods that activate the surface of the film using chemicals such as acids and alkalis. Attempts have been made to increase However, with such a physical method, the process is simple, but the resulting adhesiveness is insufficient, and with the chemical method, the process becomes complicated and there are problems such as deterioration of the working environment.

  Apart from the physical and chemical treatment methods described above, there is a method of applying an undercoat having adhesive activity to a base film and laminating an easy-adhesion layer. This method is coated on the easy-adhesion layer. It is widely used because an easy-adhesive component can be selected according to various deposited layers.

  A water-based resin is widely used as a component of the easy-adhesion layer from the viewpoint of workability, safety, and cost, but polyurethane resin, polyester resin, acrylic resin, etc. are particularly suitable for improving adhesion to the deposited metal. Is done.

Moreover, various hardeners are mix | blended with the said water-based resin, and the performance as an easily bonding layer, especially water resistance and heat resistance are improved. Examples of the curing agent used for this purpose include isocyanate compounds, melamine compounds, and epoxy compounds. For example, Japanese Patent Publication No. 56-151562 and Japanese Patent Publication No. 61-10311 disclose a method for obtaining an easily adhesive film using an isocyanate compound (see, for example, Patent Documents 1 and 2). Japanese Patent Application Laid-Open No. 8-31221 discloses that the water-resistant adhesion of the vapor deposition layer is improved by an easy adhesion layer composed of a polyester resin and a melamine compound (see, for example, Patent Document 3). JP-A-8-332706 also discloses a method for obtaining an easy-adhesive laminated film using a carbodiimide monomer containing one carbodiimide group per molecule (see, for example, Patent Document 4).
Japanese Patent Publication No.56-151562 Japanese Patent Publication No. 61-10311 Japanese Patent Laid-Open No. 8-311221 JP-A-8-332706

  However, the easy-adhesion layer using these existing technologies, especially when subjected to high-temperature hot water treatment such as boiling and retort, decreases the interlayer adhesion between the base film and the top coat layer, and as a food packaging material In some cases, there was a problem with the practical performance. That is, various curing agents and cross-linking agents used as water-based easy-adhesive coating agents have a small amount of addition, and sufficient interlayer adhesion has not been obtained. It is often impossible to respond to.

  By adding a substantially water-insoluble amino resin to an aqueous resin such as polyurethane or polyester resin as an easy-adhesion layer, an easily-adhesive plastic film excellent in heat resistance and water resistance can be obtained. Since it is insoluble, it is difficult to prepare a stable resin aqueous solution or aqueous dispersion, and the surface haze of the obtained film is high.

  The present invention solves the above-mentioned problems, has excellent adhesion to the vapor-deposited metal layer, and thereby has excellent gas barrier properties after vapor deposition, especially water vapor barrier properties, and high-temperature hot water such as boil and retort. An object of the present invention is to provide an easy-adhesive plastic film having excellent adhesion to a base film and gas barrier properties and a method for producing the same even after the treatment.

  That is, in the present invention, an easy-adhesion layer made of (A) a water-soluble or water-dispersible resin and (B) an amino resin having a triazine ring is formed on at least one surface of the base film, and the measurement is performed by the ATR-IR method. The ratio of absorbance at 1540 cm −1 / absorbance at 1340 cm −1 is 0.010 or more, and this is an easily adhesive polyester film.

  The easy-adhesion polyester film of the present invention includes an easy-adhesion layer made of (A) a water-soluble or water-dispersible resin and (B) an amino resin containing a triazine ring on at least one surface of the base film. The easy-adhesion layer is excellent in adhesion with the base film, and has sufficient strength to withstand the impact when laminating the vapor deposition layer, and also has excellent adhesion with the vapor deposition layer, Since it is suppressed that a vapor deposition layer peels from a base film or a vapor deposition layer cracks, the outstanding gas barrier property can be expressed. In this case, the (A) water-soluble or (A) water-soluble or water-dispersible resin component having the self-condensable (B) amino resin component containing a triazine ring is blended in the same amount or more. Even if the water-dispersible resin component or the (B) amino resin component is hydrophilic, it has a feature that it is durable to boil and retort treatment.

  In addition, the polyester film of the present invention having such an easy-adhesion layer contains (B) an amino resin having a triazine ring in an amount equal to or greater than (A) a water-soluble or water-dispersible resin component. By doing so, the gas barrier property and oxygen barrier property after vapor deposition are particularly excellent in water vapor barrier property, and the polyester film is particularly suitable for gas barrier packaging applications.

  The feature can be expressed by the physical property that the ratio of absorbance at 1540 cm −1 / absorbance at 1340 cm −1 measured by ATR-IR method is 0.010 or more.

  In the gas barrier property of the vapor deposition film, especially in the water vapor barrier property, the adhesion between the vapor deposition layer and the substrate film is a point, and if the adhesion of the vapor deposition layer is weak, the water penetrates the correlation and the area through which water vapor permeates increases. The water vapor barrier property is lowered. Addition of an amino resin component having a triazine ring contributes to the improvement in adhesion. The measurement by the ATR-IR method can accurately quantify the abundance of the cross-linking material component that improves the adhesion from a very thin easy-adhesion layer.

  The ratio of absorbance at 1540 cm −1 / absorbance at 1340 cm −1 as measured by the ATR-IR method is preferably 0.010 or more, particularly preferably 0.015 or more, and still more preferably 0.15 from the viewpoint of water vapor barrier properties. 020 or higher. Moreover, when this light absorbency becomes large, it means an increase in film thickness, which adversely affects the flexibility of the obtained polyester film. From this viewpoint, the ratio of absorbance at 1540 cm −1 / absorbance at 1340 cm −1 as measured by the ATR-IR method is preferably 0.2 or less.

  Moreover, oligomer precipitation / aggregation from the base film during heating is also suppressed by providing the easy-adhesion layer. Thereby, the defect by the foreign material at the time of vapor deposition is suppressed, and a higher level gas barrier film can be formed.

  The laminated polyester film of the present invention preferably has a color change value of 10 or less after melt molding. When the discoloration value exceeds 10, when the recovered pellet is used as a film raw material, the film quality is remarkably deteriorated.

  The color change value after melt molding defined in the present invention is a parameter represented by a difference in color b value between a pellet obtained by melt molding a laminated polyester film and a laminated polyester film before melt molding.

  Specifically, the laminated polyester film is cut into strips, dried under reduced pressure, melt-extruded at a temperature of 280 ° C. by a model tester, cooled in water, then cut and formed into pellets. This pellet is abbreviated as a recovered pellet. The color b value between the collected pellet and the laminated polyester film before the test is measured, and the difference between the two is defined as the color change value after melt molding. The color b value means a b value in the Lab space measured by a photoelectric colorimeter.

  The background using this parameter will be described. When manufacturing a polyester film, both ends gripped with a clip during transverse stretching with a tenter, both ends not satisfying a predetermined product width when slitting, a roll film that is degraded in quality, at the start and end of film formation At times, when changing conditions, waste films that cannot be produced due to troubles, etc., are always generated. Generally, the scrap film is crushed into flakes, melted by an extruder, discharged from a die into strands, then cut into pellets, reshaped as recovered pellets, and re-formed as a film raw material. Used.

  However, a film using a recovered pellet made of a laminated polyester film having a coating layer is deteriorated in quality due to the presence of foreign matters causing fish eyes or coloring due to the thermal history during the manufacture of the recovered pellet. For this reason, in applications where defects such as transparency, coarse protrusions caused by foreign matters, and fish eyes are problematic, particularly optical applications, it is not possible to recycle waste films that are not products as film raw materials.

  Analyzing this phenomenon in detail, re-melting a laminated polyester film with a coating layer by a model test and re-molding it into pellets, and the color change value of the film when the pellets are biaxially stretched as film raw materials (discoloration after melt-molding) By using the value) as a parameter, it was found that the quality of a film when a laminated polyester film was actually produced using a film raw material containing recovered pellets could be grasped. As a result, in order to reduce the deterioration of the quality of the film using the recovered pellets, that is, to be a recoverable laminated polyester film, the discoloration value after melt molding is preferably 10 or less.

  Furthermore, the laminated polyester film of the present invention preferably has a change in haze value after heating of 20% or less. More preferably, it is 15% or less, and particularly preferably 10% or less. If the change in haze value after heating exceeds 20%, the whitening of the film becomes significant, and the influence on the appearance and performance is neglected when used in applications where heat treatment is performed, particularly in printing and optical applications. become unable.

  The change in haze value after heating means the difference between the haze value after heating at 150 ° C. for 30 minutes and the haze value of the laminated polyester film before heating. This parameter is used for predicting and controlling the quality of heat whitening of the film when the laminated polyester film of the present invention is heat-treated in a post-processing step.

  In addition, the polyester film of the present invention having such an easy-adhesion layer contains (B) an amino resin having a triazine ring in an amount equal to or greater than (A) a water-soluble or water-dispersible resin component. By doing so, the gas barrier property and oxygen barrier property after vapor deposition are particularly excellent in water vapor barrier property, and the polyester film is particularly suitable for gas barrier packaging applications.

  ADVANTAGE OF THE INVENTION According to this invention, the easily adhesive plastic film which can maintain high water vapor | steam barrier property with respect to a vapor deposition metal layer after a hot-water process can be provided. The easy-adhesive polyester film of the present invention is extremely useful in various applications such as electric and electronic parts, building materials, photoengraving, pressure-sensitive adhesive tapes, general industrial films such as mold release and food packaging films. By using, there is an advantage that workability is improved in processing steps such as vapor deposition and lamination.

  Hereinafter, preferred embodiments of the present invention will be described in detail.

  Examples of the water-soluble or water-dispersible resin applied to the structure of the easy adhesion layer in the present invention include urethane resin, polyester resin, polyvinyl alcohol resin, and acrylic resin. Among them, urethane resin or polyester resin can be easily mixed, which is preferable in terms of barrier properties.

  Examples of the water-soluble or water-dispersible polyurethane resin applied to the structure of the easy-adhesion layer in the present invention include various polyurethane resins, polyurethane polyurea resins, and prepolymers thereof. Specific examples of such urethane resins include diisocyanate components such as tolylene diisocyanate, xylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, cyclohexane diisocyanate, isophorone diisocyanate, dicyclohexyl diisocyanate, ethylene glycol, propylene glycol, and 1,4-butane. Diol, 1,6-hexanediol, neopentyl glycol, cyclohexanedimethanol, bisphenol, polyester diol, polyether diol, polycarbonate diol, reaction product with diol component such as polyethylene glycol, urethane prepolymer having an isocyanate group at the terminal , Amino compounds, aminosulfonates, polyhydroxycarbonates Bon acid, and reaction products of such bisulfite.

  Examples of the water-soluble or water-dispersible polyester resin include various polyester resins and modified products thereof. Specific examples of such polyester resins include terephthalic acid, phthalic acid, isophthalic acid, trimellitic acid, pyromellitic acid, 2-sulfoisophthalic acid, 5-sulfoisophthalic acid, adipic acid, sebacic acid, succinic acid, and dodecane. Reaction products of polyvalent carboxylic acid components such as diacid and diol components such as ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, cyclohexanedimethanol and bisphenol In addition, modified products such as acrylic resins and epoxy resins are also included.

  Among these, one or more resins or two or more copolymers selected from aqueous aromatic polyester resins or aqueous acrylic resins having an acid value of 200 eq / t or more are preferable. This copolymer includes block bodies and graft bodies. In this case, it is necessary not to deteriorate the water resistance of the easy adhesion layer.

  Examples of the polar group that does not deteriorate the water resistance contained in the aqueous acrylic resin component in this copolymer include amine salts of carboxylic acids that decompose by heating and decrease in polarity. The amine that can be used needs to be vaporized under the drying conditions of the coating film, and examples thereof include ammonium, diethylamine, and triethylamine.

  More preferably, one or more resins selected from aqueous aromatic polyester resins or aqueous acrylic resins having an acid value of 200 eq / t or more or two or more copolymers are acid anhydrides having a double bond. It is to contain 5% by weight or more of a radical polymer composed of at least one monomer. If it is less than 5% by weight, a sufficient water resistance effect cannot be obtained.

  By introducing the acid anhydride into the resin, a crosslinking reaction can be performed between the resin molecules. In other words, the acid anhydride in the resin is converted to carboxylic acid by hydrolysis in the coating solution, and reacts with the acid anhydride or active hydrogen groups of other molecules between molecules due to thermal history during drying and film formation. Thus, ester groups and the like can be generated, and the resin of the coating layer can be cross-linked to exhibit water resistance and heat whitening prevention property.

  Examples of the monomer containing an acid anhydride having a double bond include maleic anhydride, itaconic anhydride, 2,5-norbornene dicarboxylic acid, and tetrahydrophthalic anhydride. The radical polymer may be a copolymer with another polymerizable unsaturated monomer.

  Other polymerizable unsaturated monomers include fumaric acid, monoethyl fumarate, diethyl fumarate, diester of fumaric acid such as dibutyl fumarate; maleic acid, monoethyl maleate, diethyl maleate, dibutyl maleate Monoester or diester of maleic acid such as itaconic acid, monoester or diester of itaconic acid; maleimide such as phenylmaleimide; styrene derivatives such as styrene, α-methylstyrene, t-butylstyrene, chloromethylstyrene; Alkyl acrylate, alkyl methacrylate (alkyl groups are methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, 2-ethylhexyl, Acrylic polymerizable monomers such as hexyl group, phenyl group, benzyl group, phenylethyl group, etc .; 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate-containing acrylic Monomer: Acrylamide, methacrylamide, N-methyl methacrylamide, N-methyl acrylamide, N-methylol acrylamide, N-methylol methacrylamide, N, N-dimethylol acrylamide, N-methoxymethyl acrylamide, N-methoxymethyl methacryl Amide, N-phenylacrylamide amide group-containing acrylic monomer; N, N-diethylaminoethyl acrylate, N, N-diethylaminoethyl methacrylate amino group Acrylic monomer; Epoxy group-containing acrylic monomer of glycidyl acrylate and glycidyl methacrylate; Acrylic monomer containing carboxyl group such as acrylic acid, methacrylic acid and salts thereof (sodium salt, potassium salt, ammonium salt) or salts thereof Monomer, and the like.

  In the present invention, the saponification degree and the polymerization degree of the polyvinyl alcohol resin are determined in consideration of the desired fine particle dispersibility, the viscosity of the coating solution, and the stretchability during production. It is recommended that the degree of polymerization of polyvinyl alcohol (hereinafter, all showing “number average molecular weight”) is 300 or more, more preferably 500 or more, and preferably 2600 or less, more preferably 2000 or less. The When the degree of polymerization is less than 300, the crystallization speed is too high, and sufficient stretchability may not be obtained. On the other hand, if the polymerization degree exceeds 2600, the viscosity of the PVA aqueous solution becomes too high and gelation tends to occur, which may make coating difficult.

  As the acrylic resin of the present invention, for example, an acrylic resin emulsion dispersed in water can be used, and the dispersion diameter is preferably 20 to 200 nm, more preferably 30 to 100 nm for mixing with other resins. desirable. In order to obtain a dispersion diameter of less than 20 nm, it is necessary to increase the amount of the emulsifier used from the specific surface area when preparing an acrylic emulsion by emulsion polymerization or the like, which may cause problems in terms of adhesion. If it exceeds 200 nm, fine dispersion may be difficult. Further, the glass transition temperature of the acrylic resin is preferably in the range of 0 to 80 ° C, more preferably 10 to 70 ° C. If the glass transition temperature is too low, it may be disadvantageous for blocking resistance, and if it is too high. Instability of the resin when dispersed in water may be a problem.

  Although it does not specifically limit as a monomer component which comprises an acrylic resin, For example, alkyl acrylate, alkyl methacrylate (As an alkyl group, a methyl group, an ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl) Group, t-butyl group, 2-ethylhexyl group, lauryl group, stearyl group, cyclohexyl group, phenyl group, benzyl group, phenylethyl group), 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate , Hydroxy group-containing monomers such as 2-hydroxypropyl methacrylate, acrylamide, methacrylamide, N-methyl acrylamide, N-methyl methacrylamide, N-methylol acrylamide, N-methylol methacrylate Amide group-containing monomers such as amide, N, N-dimethylolacrylamide, N-methoxymethylacrylamide, N-methoxymethylmethacrylamide, N-phenylacrylamide, N, N-diethylaminoethyl acrylate, N, N-diethylaminoethyl methacrylate, etc. Amino group-containing monomers, glycidyl acrylate, epoxy group-containing monomers such as glycidyl methacrylate, monomers such as acrylic acid, methacrylic acid and salts thereof (lithium salt, sodium salt, potassium salt, etc.) or monomers containing such salts These may be copolymerized using one or more of them. 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, crotonic acid, itaconic acid, maleic acid, fumaric acid and salts thereof (lithium salt, sodium salt, potassium salt, ammonium salt, etc.) A monomer containing a carboxyl group or a salt thereof, a monomer containing an acid anhydride such as maleic anhydride, itaconic anhydride, vinyl isocyanate, allyl isocyanate, styrene, vinyl methyl ether, vinyl ethyl ether, vinyl trisalkoxysilane, Alkyl maleic acid monoester, alkyl fumaric acid monoester, acrylonitrile, methacrylonitrile, alkyl itaconic acid monoester, vinylidene chloride, vinyl chloride, vinyl acetate and the like can be used. In addition, modified acrylic copolymers such as block copolymers modified with polyester, urethane, epoxy and the like, graft copolymers, and the like can also be used.

  Preferable acrylic resins used in the present invention include copolymers selected from methyl methacrylate, ethyl acrylate, n-butyl acrylate, 2-hydroxyethyl acrylate, acrylamide, N-methylol acrylamide, and acrylic acid.

    The method for polymerizing the acrylic resin emulsion in the present invention is not particularly limited, but usually emulsion polymerization, suspension polymerization and the like are preferably used.

  For the easy-adhesion layer in the present invention, it is necessary to use an amino resin having a triazine ring. Examples of the amino resin include formaldehyde adducts such as melamine and benzoguanamine, and alkyl ether compounds based on alcohols having 1 to 6 carbon atoms. Specific examples include methoxylated methylol melamine, methoxylated methylol benzoguanamine, butoxylated methylol melamine, butoxylated methylol benzoguanamine, and the like, preferably methoxylated methylol melamine, butoxylated methylol melamine, and methoxylated methylol benzoguanamine, each alone Or it can be used in combination.

  In the easy-adhesion layer in the present invention, the composition ratio of (A) a water-soluble or water-dispersible resin and (B) an amino resin having a triazine ring needs to be A / B = 60/40 to 5/95 (mass ratio). The ratio is preferably 45/55 to 10/90, more preferably 50/50 to 15/85. By setting it within this range, water dispersibility can be ensured, the adhesiveness between the base film and the vapor deposition layer is excellent, and excellent gas barrier properties, particularly water vapor barrier properties can be exhibited. (B) Adhesiveness cannot be obtained when the blending ratio of the amino resin having a triazine ring to the (A) water-soluble or water-dispersible resin is lower than 40% by mass, and adhesion obtained even when the amount is higher than 95% by mass. The improvement in the property is not recognized, but the hot water / retort adhesiveness decreases.

  In the present invention, the concentration of the aqueous solution or aqueous dispersion of the easy-adhesion layer applied to the base film is suitably 1 to 30% by mass, and 3 to 10 in view of the coating property and workability on the film. More preferred is mass%.

  In addition, the aqueous solution or the aqueous dispersion and the base film can be blended with various additives such as an antistatic agent, an antioxidant and a lubricant as necessary, as long as the effects of the present invention are not impaired. is there.

  Although the base film which forms the easily-adhesive easily-adhesive layer in this invention is not specifically limited, When it applies to a polyester film especially, the outstanding effect will be acquired. Examples of the polyester film include polyethylene terephthalate, polybutylene terephthalate, polyethylene 2,6-naphthalate and the like, and polyethylene terephthalate film (PET film) is most preferable. It is an excellent food packaging material with excellent mechanical properties, heat resistance and transparency.

  As a method for coating the base film with the aqueous solution or aqueous dispersion of the easy-adhesion layer in the present invention, for example, the above aqueous solution or aqueous dispersion is applied to the base film before the end of biaxial orientation crystallization, that is, the unstretched or uniaxially stretched film It can be applied to a so-called in-line coating method in which a biaxially stretched film is obtained through coating and heat treatment. The in-line coating method applies the above aqueous solution or aqueous dispersion to an unstretched or uniaxially stretched film, and then performs a stretching heat treatment. Therefore, it is possible to make the easy adhesion layer thinner than the post-coating method in which coating is performed after stretching. The adhesion between the base film and the vapor deposition layer can be improved. Moreover, since the application process of an easily bonding layer is integrated in the manufacturing process of a base film, manufacture of this easily bonding coat film is possible at low cost. In addition, regarding the extending | stretching method of a base film, a tenter type simultaneous biaxial stretching method and a sequential biaxial stretching method are applicable according to a material.

  In the present invention, the thickness of the easy-adhesion layer formed by applying and heat-treating an aqueous solution or aqueous dispersion is preferably 0.01 to 0.5 μm. If it is thinner than 0.01 μm, the adhesiveness is lowered, and if it is thicker than 0.5 μm, there is no significant change in easy adhesiveness, etc. There are adverse effects such as damage to the easily adhesive layer during unwinding and film cutting, which is disadvantageous in terms of cost. As a method for applying the aqueous dispersion, any known method can be selected. For example, a bar coating method, an air knife coating method, a reverse roll coating method, or a gravure roll coating method can be applied.

  The easily-adhesive plastic film provided by the present invention is provided with various performances by performing surface activation treatment such as corona treatment on the surface, printing, various functional coatings, laminating, etc. It is also possible to improve further.

  Hereinafter, the present invention will be described in detail by way of examples. The film properties obtained in each example were measured and evaluated by the following methods.

(1) Absorbance measurement at 1540 cm-1 and 1340 cm-1 by ATR method Using a Fourier transform infrared spectrophotometer (manufactured by Perkin Elmer), the absorbance was determined by solid ATR method. The crystal was an Se crystal, and both the background measurement and the sample measurement were performed after the inside of the data chamber was sufficiently replaced with nitrogen. The quantification is based on a line connecting the minimum values before and after the corresponding peak as a baseline (a line connecting the minimum values near 1510 and 1600 cm-1 at 1540 cm-1, and around 1310 cm-1 at 1340 cm-1. , A line connecting the minimum values in the vicinity of 1360 cm −1), the peak height of the corresponding wavelength was read and calculated. In addition, the measurement was performed twice and the average value was calculated | required.

(2) Change in haze value after heating Two films are cut into 8 cm × 10 cm strips, and each eight points are measured twice with a haze meter (TC-H3DP, manufactured by Tokyo Denshoku Co., Ltd.). The average of the total 16 measured values is defined as the initial haze value H0 (%). These strip-shaped films were held with clips and heated in a hot air oven at 150 ° C. for 30 minutes. After allowing the film to cool, the haze value H1 (%) after heating is measured in the same manner as in the above initial haze measurement method. The difference between these haze values (H1-H0) is defined as the change in haze value after heating.

(3) Discoloration value after melt molding The laminated polyester film having a coating layer is cut into a strip shape and dried at 135 ° C. under a reduced pressure of 133 Pa for 6 hours, and then an extruder (PCM-30 manufactured by Ikeji Iron Works Co., Ltd.). The molten resin was extruded in a strand form from a nozzle having a diameter of 5 mm at a discharge rate of 200 g / min, a cylinder temperature of 280 ° C. and a rotation speed of 80 rpm, cooled in a water bath, and then cut to obtain a recovered pellet. . The elapsed time from the start of supplying the strip-shaped film to PCM-30 to the start of the outflow of the molten resin from the nozzle was 130 seconds. The b value (b) of the recovered pellets and the b value (b0) of the laminated film before the test are measured with a color difference meter, and these differences are defined as the color change values after melt molding.
Discoloration value = b−b0

(4) Production of laminate film Obtained by an electron beam evaporation method using particulate SiO ₂ (purity 99.9%) and Al ₂ O ₃ (purity 99.9%) of about 3 mm to 5 mm as a deposition source. A mixed gas barrier layer of aluminum oxide and silicon dioxide was formed on the easy adhesion film. The vacuum layer contains an unwinding part, a coating part, and a winding part, and can be continuously deposited on the film. The pressure during vapor deposition was adjusted to 1.0 × 10 ⁻⁴ Torr. SiO ₂ and Al ₂ O ₃ were divided into two without mixing. An electron gun (hereinafter referred to as an EB gun) was used as a heating source, and two types of raw materials were heated in a time division manner. At that time, the emission current of the EB gun was set to 1.2 A, and the heating ratio of SiO ₂ to Al ₂ O ₃ was heated at 1: 2. The film feed rate was 130 m / min, and a film having a thickness of 150 mm (angstrom) was formed. Moreover, the temperature of the roll for cooling the film at the time of vapor deposition was adjusted to -10 degreeC. Next, a polyurethane adhesive (TM-590 /, manufactured by Toyo Morton Co., Ltd.) is applied to the vapor deposition surface of the film at about 3 μm, heat treated at 80 ° C., and then a low density polyethylene film (L6102 thickness 40 μm, manufactured by Toyobo). Dry lamination was performed at a nip pressure of 490 kPa on a metal roll heated to 80 ° C. to obtain a laminate film.

(5) Hot water treatment of laminate film The test piece was boiled in 95 ° C. hot water for 30 minutes.

(6) Measurement of oxygen barrier The oxygen permeability of the prepared film was measured using an oxygen permeability measuring device (OX-TRAN100 manufactured by Modern Controls).

(7) Measurement of water vapor barrier The prepared film was subjected to 40 ° C., 100% R.D. H. The measurement was performed using a measuring device (PARMATRAN-W) manufactured by MOCON, USA.

(8) Measurement of Lami Strength The prepared sample was cut into a length of 15 cm and a width of 1.5 cm, and distilled water was appropriately dropped onto the peeling surface with a dropper, and then measured under conditions of a distance between chucks of 1 cm and 100 mm / min.

Example 1
78 parts by mass of an aqueous polyurethane resin (HW340, manufactured by Dainippon Ink Co., Ltd., solid content 25%) was added to 22 parts by mass of amino resin (Cymel 370, manufactured by Mitsui Cytec Co., Ltd., solid content 88%) and stirred for 30 minutes. After that, it was diluted with water and isopropanol to adjust the concentration so that the total solid content concentration was 5% by mass, and further stirred for 20 minutes to obtain an aqueous resin mixture. A PET having an intrinsic viscosity of 0.62 (30 ° C., phenol / tetrachloroethane = 60/40) is pre-crystallized, then dried, extruded at 280 ° C. using an extruder having a T die, and a drum having a surface temperature of 40 ° C. It was rapidly cooled and solidified to obtain an amorphous sheet. The obtained sheet was stretched 4.0 times at 100 ° C. in the longitudinal direction between the heating roll and the cooling roll. On one side of the obtained uniaxially stretched film, the above-mentioned coating solution is applied by a fountain bar coating method so that the resin solid content thickness before stretching is 0.1 μm, and is then dried and guided to a tenter and preheated at 100 ° C. The film was stretched 4.0 times at 120 ° C. and heat-treated at 225 ° C. while relaxing 6% in the transverse direction to obtain a biaxially stretched polyester film having a thickness of 12 μm. Table 1 shows the results obtained by subjecting the easy-adhesion layer-coated film to vapor deposition and measuring the laminate strength.

(Examples 2, 3, comparative examples 1, 2, 3, 4)
Except having changed the resin component and the compounding ratio as shown in Table 1, the aqueous resin compounding liquid and the easily bonding layer coat film were obtained in the same procedure as Example 1. Table 1 shows the results of evaluating the aqueous resin compounding liquid and the results of measuring the laminate strength of the film.

(Example 4)
(Preparation of copolyester resin)
In a stainless steel autoclave equipped with a stirrer, a thermometer, and a partial reflux condenser, 163 parts by weight of dimethyl terephthalate, 163 parts by weight of dimethyl isophthalate, 169 parts by weight of 1,4 butanediol, 324 parts by weight of ethylene glycol, and Tetra-n-butyl titanate (0.5 part by weight) was charged, and a transesterification reaction was performed from 160 ° C. to 220 ° C. over 4 hours.

  Next, 14 parts by weight of fumaric acid and 203 parts by weight of sebacic acid were added, and the temperature was raised from 200 ° C. to 220 ° C. over 1 hour to carry out an esterification reaction. Next, the temperature was raised to 255 ° C., and the reaction system was gradually reduced in pressure, and then reacted for 1 hour 30 minutes under a reduced pressure of 29 Pa to obtain a copolymerized polyester resin (A-1). The obtained copolyester resin was light yellow and transparent and had a weight average molecular weight of 18,000.

(1) Production of graft resin In a reactor equipped with a stirrer, a thermometer, a reflux device and a quantitative dropping device, 75 parts by weight of copolymer polyester resin (A-1), 56 parts by weight of methyl ethyl ketone and 19 parts by weight of isopropyl alcohol were added. The mixture was heated and stirred at 65 ° C. to dissolve the resin. After the resin was completely dissolved, 15 parts by weight of maleic anhydride was added to the polyester solution.

  Next, a solution prepared by dissolving 10 parts by weight of styrene and 1.5 parts by weight of azobisdimethylvaleronitrile in 12 parts by weight of methyl ethyl ketone was dropped into the polyester solution at 0.1 ml / min, and stirring was further continued for 2 hours. After sampling for analysis from the reaction solution, 5 parts by weight of methanol was added. Next, 300 parts by weight of water and 15 parts by weight of triethylamine were added to the reaction solution and stirred for 1 hour.

Thereafter, the internal temperature of the reactor was raised to 100 ° C., and methyl ethyl ketone, isopropyl alcohol and excess triethylamine were distilled off to obtain an aqueous dispersion graft polymerization resin B-1. The water-dispersed graft resin (B-1) was light yellow and transparent. The acid value of this graft product was 1400 eq / t.
Except having changed the resin component and the compounding ratio as shown in Table 1, the aqueous resin compounding liquid and the easily bonding layer coat film were obtained in the same procedure as Example 1. Table 1 shows the results of evaluating the aqueous resin compounding liquid and the results of measuring the laminate strength of the film.

  The easy-adhesive plastic film of the present invention has excellent adhesion to the vapor-deposited metal layer, and in particular has excellent water vapor barrier properties after vapor deposition, and can be used in a wide range of application fields such as packaging materials and industrial materials. It is important to contribute to the industry.

Claims (2)

At least one surface of the base polyester film is composed of (A) a water-soluble or water-dispersible polyurethane resin or a water-soluble or water-dispersible polyester resin, (B) an amino resin having a triazine ring, and the component (A) An easy-adhesion layer having a mass ratio of component (B) of 50/50 to 15/85 is formed, and the ratio of absorbance at 1540 cm −1 / absorbance at 1340 cm −1 as measured by the ATR-IR method is 0.010 or more. An easily adhesive polyester film characterized by (A) An aqueous solution or an aqueous dispersion containing a water-soluble or water-dispersible polyurethane resin and (B) an amino resin, wherein the mass ratio of the component (A) to the component (B) is 50/50 to 15/85. 2. The method for producing a plastic film according to claim 1 , wherein the base film before biaxial orientation crystallization is applied, dried, then stretched in at least one direction and then heat-treated.