JP6321578B2 - Gas barrier coating agent and gas barrier film using the same - Google Patents

Description

  The present invention relates to a gas barrier coating agent and a film using the same. More specifically, the polyhydroxyurethane resin characterizing the gas barrier coating agent of the present invention comprises a crosslinked resin film layer formed by irradiating ultraviolet rays or an electron beam, and a crosslinked coating film exhibiting a high gas barrier property even under high humidity. In addition, since carbon dioxide can be incorporated into the chemical structure of the resin, it is possible to provide a highly environmentally friendly product.

  Films having gas barrier properties are mainly used for the purpose of protecting the contents, and are widely used in the industrial material field, mainly for use as packaging materials for foods and pharmaceuticals. As a material for forming a gas barrier layer for a film having gas barrier properties (hereinafter referred to as “gas barrier film”), a resin in which the formed film exhibits gas barrier properties is used. Typical resins include, for example, ethylene-vinyl alcohol copolymer resin (hereinafter abbreviated as EVOH) and vinylidene chloride resin (hereinafter abbreviated as PVDC). These resins having gas barrier properties can be used alone, but as described below, in general, a multilayer film is formed using other resin materials and used as a material for forming a gas barrier layer therein. It is used.

  For example, EVOH is used for composite films by co-extrusion molding with a resin such as polypropylene (hereinafter abbreviated as PP). However, EVOH is inferior in solubility in an organic solvent, and is therefore a coating method. It is unsuitable for the production of films and coating films. On the other hand, PVDC can be molded by a coating method and can be applied to various base materials. Therefore, PVDC is used as a coating film for food packaging and the like. However, since PVDC has a high chlorine content, another problem has been pointed out that dioxin is generated when it is discarded (incinerated).

  In recent years, global warming has been a problem, and studies are underway to reduce the use of petroleum-derived materials and to use biomass-derived materials as polymer raw materials. For example, in polyethylene terephthalate (hereinafter abbreviated as PET) used for packaging materials, a production method using biomass-derived components has been almost established, and in polyethylene and PP, studies on using biomass-derived components have been made. Has been done. However, regarding resins such as EVOH and PVDC that are widely used as the material for forming the barrier layer described above, it is difficult to replace them with biomass-derived components due to problems in the chemical structure, and the investigation is not progressing at present. .

  On the other hand, a polyhydroxyurethane resin synthesized using carbon dioxide as a raw material is used as a material for forming a gas barrier layer as a new environmentally friendly barrier material that has a completely different chemical structure from EVOH and PVDC. It has been proposed (see Patent Document 1). The polyhydroxyurethane resin described in Patent Document 1 is a resin that can cope with environmental problems in that it has a carbon dioxide-derived —O—CO— bond in the chemical structure of the resin. Patent Document 1 clearly shows that a chemical structure having a hydroxyl group at a neighboring site is characteristic, and a gas barrier property that is not found in conventional polyurethane resins is expressed by this chemical structure site having a hydroxyl group.

  In addition, as a technique for using a polyhydroxyurethane resin, a method of introducing an unsaturated group by modifying the hydroxyl group of the polyhydroxyurethane resin is known for the purpose of improving the thermal characteristics of the formed film (non-patent document). 1).

JP 2012-172144 A

J. et al. Polym. Sci. PartA 45 3400 2007

  However, according to the study by the present inventors, a resin that exhibits gas barrier properties due to hydrogen bonding of hydroxyl groups in the structure, such as polyhydroxyurethane resin, has a problem that the gas barrier properties decrease under high humidity, On the other hand, in order to improve moisture resistance, it is necessary to chemically modify the hydroxyl group with a hydrophobic compound or the like. In this case, there is a problem that the gas barrier property itself is deteriorated, which is a trade-off.

  On the other hand, the technique described in Non-Patent Document 1 describing the modification of the hydroxyl group of the polyhydroxyurethane resin described above is aimed at improving the thermal characteristics of the formed film. The use of a gas barrier film using sapphire has not been studied at all.

  The object of the present invention is to improve the gas barrier property deterioration problem particularly under high humidity while being a gas barrier coating agent using a polyhydroxyurethane resin that expresses gas barrier property by a hydroxyl group and a gas barrier film using the same. The same gas barrier properties as when using conventional materials such as EVOH and PVDC can be realized, films can be produced by coating methods, and there is no problem of chlorine when discarded (incinerated) as in conventional materials To provide high-quality materials.

  As a result of intensive investigations to solve the above-described problems of the prior art, the present inventors have, in the past, included unmodified polyhydroxyurethanes among the hydroxyl group chemical modification methods that reduce gas barrier properties. The present inventors have completed the present invention by finding conditions that maintain a gas barrier property equivalent to the above and improve the gas barrier property under high humidity.

［上記一般式（１）中のＸは、脂肪族炭化水素、脂環式炭化水素又は芳香族炭化水素からなるモノマー単位由来の化学構造を示し、該構造中には、酸素原子、窒素原子、硫黄原子又はエステル結合を含んでもよい。Ｙ₁は、下記式（２）又は（４）の水酸基を有する化学構造のいずれかを示し、Ｙ₂は、下記式（２）又は（３）の水酸基を有する化学構造のいずれかを示し、該Ｙ₁及びＹ₂の組み合わせが異なる繰り返し単位が混在していてもよい。さらに、Ｙ₁及びＹ₂中の水酸基の一部が、下記一般式（５）の不飽和基を有する基で置換されていることを要する。Ｚは、脂肪族炭化水素、脂環式炭化水素又は芳香族炭化水素からなるモノマー単位由来の化学構造を示し、該構造中には酸素原子、窒素原子又は硫黄原子を含んでもよい。］

［式（５）中、Ｒ₁は、炭素数１〜１０のアルキレン基であり、酸素原子を含んでいてもよい。Ｒ₂は、水素原子又はメチル基である。ｎは１又は２である。］ That is, said subject is achieved by the following this invention. The present invention is a gas barrier coating agent comprising an unsaturated group-containing polyhydroxyurethane resin, which is cured by ultraviolet rays or electron beams to form a crosslinked resin film, the unsaturated group-containing polyhydroxyurethane resin. Wherein a part of the hydroxyl group has a repeating unit represented by the following general formula (1), which is substituted with a group having an unsaturated group represented by the following general formula (5). A gas barrier coating agent is provided.

[X in the general formula (1) are fat-aliphatic hydrocarbons, show the chemical structure derived from a monomer unit composed of an alicyclic hydrocarbon or an aromatic hydrocarbon, in the structure, an oxygen atom, a nitrogen atom , May contain a sulfur atom or an ester bond. Y ₁ represents either a chemical structure having a hydroxyl group of the following formula (2) or (4), Y ₂ represents either a chemical structure having a hydroxyl group of the following formula (2) or (3), Repeating units having different combinations of Y ₁ and Y ₂ may be mixed. Furthermore, it is required that a part of the hydroxyl groups in Y ₁ and Y ₂ is substituted with a group having an unsaturated group of the following general formula (5). Z is alicyclic aliphatic hydrocarbons, show the chemical structure derived from a monomer unit composed of an alicyclic hydrocarbon or aromatic hydrocarbon may contain an oxygen atom, a nitrogen atom or a sulfur atom in the structure. ]

[In Formula (5), R < ₁ > is a C1-C10 alkylene group, and may contain the oxygen atom. R ₂ is a hydrogen atom or a methyl group. n is 1 or 2. ]

  The following are mentioned as a preferable form of the gas-barrier coating agent of this invention. That is, the unsaturated group content of the unsaturated group-containing polyhydroxyurethane resin is in the range of 0.3 meq / g to 2.5 meq / g, and the hydroxyl value is in the range of 10 mgKOH / g to 250 mgKOH / g. The unsaturated hydroxy group-containing polyhydroxyurethane resin synthesized with carbon dioxide as one of the raw materials, a compound having two five-membered cyclic carbonate structures in one molecule, and two in one molecule. It is obtained by polyaddition reaction with a compound having one amino group, and 1-30% by mass of the mass of the coating layer formed by the unsaturated group-containing polyhydroxyurethane resin is derived from the carbon dioxide. The —O—CO— bond is occupied.

  Another embodiment of the present invention is a gas barrier film in which the film is composed of a single layer or multiple layers, and at least one layer constituting the film is a layer having gas barrier properties, and the layer having gas barrier properties is Provided is a gas barrier film that is a crosslinked resin film layer formed by irradiating any one of the above gas barrier coating agents with ultraviolet rays or electron beams.

As a preferred form of the gas barrier film of the present invention, the thickness of the gas barrier layer is 0.1 to 100 μm, and the oxygen permeability of the film is 23 ° C. relative humidity 65% and 23 ° C. relative humidity 90%. In the constant temperature and constant humidity, it is mentioned that all are 50 ml / m ² · 24 h · atm or less.

  According to the present invention, carbon dioxide, which is a useful resin corresponding to environmental problems, can be synthesized as one of the raw materials. The problem of deterioration of gas barrier property under humidity is improved, the same gas barrier property as when using a material such as conventional EVOH or PVDC can be realized, a film can be produced by a coating method, and as in conventional materials An excellent material with high practicality without the problem of chlorine at the time of disposal (incineration) is provided. More specifically, according to the present invention, a material excellent in gas barrier properties, mechanical strength and transparency can be provided. Also, when carbon dioxide is used as one of the raw materials, the environmental load is also considered in this respect. It is possible to provide materials that contribute to the reduction of energy consumption. Furthermore, according to the present invention, after coating the coating agent of the present invention containing a polyhydroxyurethane resin obtained by chemically modifying a hydroxyl group in the structure with a specific group into which an unsaturated group is introduced, an ultraviolet ray / electron beam Since the crosslinked resin film formed by curing by irradiating becomes a film layer exhibiting the above functions, an excellent gas barrier film can be easily provided. Since the gas barrier film is used for containers for pharmaceuticals and foods, mechanical strength is required in addition to the gas barrier property. However, in the present invention, a part of the hydroxyl group of polyhydroxyurethane is a double bond-containing group. The effect of improving the mechanical strength such as the strength at break as well as the humidity dependence of the gas barrier property generated in the gas barrier film, such as the deterioration of the gas barrier property, is expected to be widely used.

IR spectrum of the crosslinked coating film of Example 1 IR spectrum of the crosslinked coating film of Example 4 IR spectrum of the crosslinked coating film of Example 5

Next, the present invention will be described in more detail with reference to the best mode for carrying out the invention.
The gas barrier coating agent of the present invention comprises an unsaturated group-containing polyhydroxyurethane resin, which is cured by ultraviolet rays or electron beams to form a crosslinked resin film. The resin has a repeating unit represented by the following general formula (1) in which a part of the hydroxyl group is substituted with a group containing an unsaturated group represented by the following general formula (5). Features. That is, the polyhydroxyurethane resin characterizing the present invention has a specific unsaturated group in its structure, and all or a part of the unsaturated group is polymerized by irradiation with ultraviolet rays / electron beams, resulting in high humidity. It is possible to form a crosslinked resin film layer having a sufficient gas barrier property even below. Since the crosslinked resin film layer is also excellent in mechanical strength and transparency, it can be expected to be widely used and its practical value is extremely high.

  More specifically, the polyhydroxyurethane resin characterizing the present invention has a repeating unit represented by the general formula (1) having an unsaturated group in its structure, and more specifically, It is essential to have at least one of the chemical structures represented by the following general formula. Hereinafter, the polyhydroxyurethane resin characterizing the present invention is also referred to as a polymer (A) having an unsaturated group.

［上記いずれかの式中、Ｒ₁は、炭素数１〜１０のアルキレン基であり、酸素原子を含んでいてもよい。Ｒ₂は、水素原子又はメチル基である。ｎは１又は２である。］

[In any one of the above formulas, R ₁ is an alkylene group having 1 to 10 carbon atoms and may contain an oxygen atom. R ₂ is a hydrogen atom or a methyl group. n is 1 or 2. ]

  The polymer (A) having an unsaturated group that characterizes the present invention can be produced, for example, as follows. For example, a (meth) acryloyl group is polymerized by reacting a hydroxyl group of a polyhydroxyurethane resin with a (meth) acryl compound having an isocyanate group as a reactive group in an amount of 0.01 to 0.9 equivalent to the hydroxyl group. A polyhydroxyurethane resin having a repeating unit of the main chain can be obtained.

  In the above, examples of the (meth) acrylic compound having an isocyanate group for introducing an unsaturated group into the polyhydroxyurethane resin include the following.

  The reaction between the polyhydroxyurethane resin and the (meth) acrylic compound having an isocyanate group for introducing an unsaturated group as described above is not particularly limited, and can be obtained by, for example, the following method. That is, in the presence of an organic solvent or in the absence of a solvent, a polyhydroxyurethane resin and a (meth) acrylic compound having an isocyanate group for introducing an unsaturated group are mixed, and a temperature of 30 to 200 ° C. is 4 to 4 It can be obtained by reacting for 24 hours.

  As the organic solvent used above, an organic solvent inert to the isocyanate group or an organic solvent less active than the reaction component with respect to the isocyanate group can be used. Specific examples of the organic solvent include ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; Aromatic hydrocarbon solvents; aliphatic hydrocarbon solvents such as n-hexane; ether solvents such as dioxane and tetrahydrofuran; ester solvents such as ethyl acetate, butyl acetate and isobutyl acetate; ethylene glycol ethyl ether acetate and propylene glycol Glycol ether ester solvents such as methyl ether acetate, 3-methyl-3-methoxybutyl acetate and ethyl-3-ethoxypropionate; amide solvents such as dimethylformamide and dimethylacetamide; , And the like lactam-based solvents such as-2-pyrrolidone.

  A catalyst may be added to this reaction as necessary. Examples of the catalyst include metals such as dibutyltin laurate, dioctyltin laurate, stannous octoate, zinc octylate, and tetra n-butyl titanate. Examples include salts of organic and inorganic acids, organic metal derivatives, organic amines such as triethylamine, diazabicycloundecene catalysts, and the like.

  This reaction can also be performed in the presence of a polymerization inhibitor for suppressing polymerization of unsaturated bonds during the reaction, if necessary. The compound that can be used as the polymerization inhibitor is not particularly limited, and includes phenol-based polymerization inhibitors such as p-methoxyphenol, quinone-based polymerization inhibitors such as benzoquinone, 2,2′-methylene-bis (6-tert-butyl-4) -Hindered phenol polymerization inhibitors such as ethylphenol), aromatic amine polymerization inhibitors such as phenothiazine, sulfur polymerization inhibitors such as diphenylthiourea, 2,2,6,6-tetramethylpiperidine-1- Any stable radical compound such as oxyl can be used.

  The polyhydroxyurethane resin that is a raw material for the polymer (A) having an unsaturated group that characterizes the present invention is a compound having two 5-membered cyclic carbonate groups in one molecule (hereinafter referred to as a cyclic carbonate compound). It is synthesized using a polyaddition reaction with a compound having two amino groups in one molecule (hereinafter referred to as an amine compound). As shown in the following formula, the cyclic carbonate compound used in this case is preferably synthesized by a reaction between an epoxy compound and carbon dioxide. Specifically, as a reaction condition of the following formula, for example, in an atmosphere of carbon dioxide in which an epoxy compound as a raw material is pressurized to about atmospheric pressure to about 1 MPa at a temperature of 0 ° C. to 160 ° C. in the presence of a catalyst. And reacting for about 4 to 24 hours. As a result, a cyclic carbonate compound in which carbon dioxide is immobilized at the ester moiety can be obtained. By using the cyclic carbonate compound synthesized using carbon dioxide as a raw material as described above, —O—CO— of the urethane bond in the general formula (1) is configured using carbon dioxide as a raw material. . As a result, the gas barrier coating agent of the present invention and the gas barrier film formed using the same are valuable as products that can cope with environmental problems. The —O—CO— bond in the general formula (1) derived from carbon dioxide accounts for 1 to 40% by mass of the total mass of the polyhydroxyurethane resin as the carbon dioxide content. A larger number is preferable from the viewpoint of environmental compatibility.

  A compound having two epoxy groups in one molecule that can be used when synthesizing a compound having two five-membered cyclic carbonate groups in one molecule from carbon dioxide, which is a raw material for the above-described polyhydroxyurethane resin, Any known one can be used. What is preferable in the present invention is exemplified below.

  For example, those having two epoxy groups in one molecule and having a benzene skeleton and an aromatic polycyclic skeleton are exemplified by the following compounds. R in any of the following formulas is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms.

  Further, for example, those having two epoxy groups in one molecule and having an aliphatic or alicyclic skeleton are exemplified by the following compounds. R in any of the following formulas is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms.

  Moreover, as a compound which has two amino groups in 1 molecule used as the raw material of the above-mentioned polyhydroxyurethane resin, any conventionally well-known thing can be used. Suitable examples include ethylenediamine, 1,3-diaminopropane, 1,4-diaminobutane, 1,6-diaminohexane, 1,8-diaminooctane, 1,10-diaminodecane, 1,12- Chain aliphatic diamines such as diaminododecane, isophorone diamine, norbornane diamine, cyclic aliphatic diamines such as 1,4-cyclohexane diamine, piperazine, aliphatic diamines having aromatic rings such as xylene diamine, metaphenylene diamine, diaminodiphenyl methane, etc. Of the aromatic diamine.

  Although the manufacturing method of the said polyhydroxy urethane resin is not specifically limited, For example, it can obtain by the following methods. That is, it can be obtained by mixing a cyclic carbonate compound and an amine compound as described above in the presence of an organic solvent or in the absence of a solvent and reacting at a temperature of 40 to 200 ° C. for 4 to 24 hours.

  As the solvent that can be used in the production of the above-described polyhydroxyurethane resin, any solvent can be used as long as it is an inert organic solvent with respect to the raw material to be used and the obtained polyhydroxyurethane resin. Examples of preferable ones include, for example, methyl formate, ethyl formate, propyl formate, methyl acetate, ethyl acetate, butyl acetate, tetrahydrofuran, dioxane, toluene, xylene, dimethylformamide, dimethyl sulfoxide, perchlorethylene, trichloroethylene, methanol, ethanol , Propanol, ethylene glycol, propylene glycol, ethylene glycol monomethyl ether, ethylene glycol dimethyl ether, propylene glycol methyl ether, diethylene glycol monomethyl ether, and diethylene glycol dimethyl ether.

  As described above, the production of the polyhydroxyurethane resin used in the present invention can be carried out without using a catalyst, but in order to accelerate the reaction, it should be carried out in the presence of a catalyst as listed below. Is also possible. For example, basic catalysts such as triethylamine, tributylamine, diazabicycloundecene (DBU), triethylenediamine (DABCO) and pyridine, and Lewis acid catalysts such as tetrabutyltin and dibutyltin dilaurate can be used. The preferable usage-amount of these catalysts is 0.01-10 mass parts with respect to the total amount (100 mass parts) of the carbonate compound and amine compound to be used.

  The polymer (A) having an unsaturated group that characterizes the present invention constitutes a coating agent, and it is preferable to use a polymer having a weight average molecular weight of 1,000 to 1,000,000 in consideration of its coating property. Further, according to the study by the present inventors, the preferred unsaturated group content in the polymer (A) having an unsaturated group constituting the coating agent of the present invention is 0.3 meq / g to 2.5 meq / g. Furthermore, the hydroxyl value (JIS K1557-1) which shows the amount of hydroxyl groups in the polymer (A) having an unsaturated group suitable for the present invention is 10 mgKOH / g to 250 mgKOH / g. According to the study by the present inventors, by setting the above range, a part of the hydroxyl groups of the polyhydroxyurethane resin used as a raw material is chemically modified, and a suitable amount of unsaturated groups is introduced into the resin. As a result, the effect of the present invention of improving the gas barrier property under high humidity can be obtained more stably while suppressing the deterioration of the gas barrier property caused by chemically modifying the hydroxyl group.

  In addition, the —O—CO— bond in the general formula (1) derived from carbon dioxide of the polymer (A) having an unsaturated group characterizing the present invention is 1 in the total mass of the compound as the carbon dioxide content. It becomes the quantity which occupies -30 mass%.

  The unsaturated group content, hydroxyl value, and carbon dioxide content in the polymer (A) having an unsaturated group described above have a cyclic carbonate compound, an amine compound, and an isocyanate group used as raw materials (meth). It is determined by the molecular weight and blending ratio of the acrylic compound. Therefore, these values can be adjusted by selecting an appropriate combination from the usable compounds described above.

Next, the gas barrier film of the present invention obtained using the gas barrier coating agent of the present invention described above will be described. The gas barrier film of the present invention is composed of a single layer or multiple layers, and at least one layer constituting the film is a layer having a gas barrier property, and the layer having the gas barrier property is a gas barrier coating agent of the present invention. And a crosslinked resin film layer formed by curing by irradiation with ultraviolet rays or electron beams. That is, the crosslinked resin film layer that characterizes the gas barrier film of the present invention is a layer made of the polymer (A) having an unsaturated group, and all or a part of the unsaturated groups of the polymer (A) are ultraviolet rays. -It is formed by polymerizing by electron beam irradiation. As described above, in the polyhydroxyurethane resin constituting the gas barrier coating agent of the present invention, a part of the hydroxyl group is substituted with a group having an unsaturated group having a specific structure, and this is subjected to ultraviolet rays or electrons. By irradiating a line, it is possible to realize formation of a crosslinked resin film layer by UV curing or EB curing. The formed cross-linked resin film layer is made of a resin that exhibits gas barrier properties due to hydrogen bonding of hydroxyl groups, but solves the problem of the prior art that the gas barrier properties decrease under high humidity. . Specifically, the thickness of the gas barrier layer is 0.1 to 100 μm, and the oxygen permeability of the film is 23 ° C. relative humidity 65% and 23 ° C. relative humidity 90% constant temperature and humidity. Is preferably 50 ml / m ² · 24 h · atm or less.

  As described above, the gas barrier film of the present invention having a cross-linked resin film layer formed by using the gas barrier coating agent of the present invention uses a UV curing system or an EB curing system for a polymer having an unsaturated group. Obtained by curing. The UV curing system and the EB curing system are curing systems that have a low environmental load, such as a curing temperature lower than that of a thermal curing system, a short processing time, and further, no volatile components are generated during curing.

  As a method for obtaining the gas barrier film as a single layer, for example, a polymer (A) solution having an unsaturated group is coated on a release paper, dried and then cured by a UV curing system or an EB curing system. There is a method of obtaining a polymer obtained by hot melt coating a polymer (A) having an unsaturated group in the form of a release paper and curing it with a UV curing system or an EB curing system.

  Examples of a method for obtaining a multilayer film containing the gas barrier film include a coextrusion method, a coating method, and a laminating method. As the co-extrusion method, for example, a multilayer film is formed by using a polymer (A) having an unsaturated group as one of raw materials, and then the gas barrier is cured by a UV curing system or an EB curing system. A multilayer film including a conductive film can be obtained.

  As the coating method, for example, a solution of a polymer (A) having an unsaturated group is applied on a base material, and a crosslinked resin film layer is formed by a UV or EB curing system through a drying process. Examples thereof include a method in which a polymer (A) having an unsaturated group not containing a solvent is hot-melt coated on a substrate and cured by a UV curing system or an EB curing system.

  Examples of the laminating method include a method in which a base material and a film prepared as a single layer are bonded to each other through an adhesive.

  Examples of the base material used above include polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, fluororesin, polycarbonate, polyacetate, polyester, polyamide, polyimide, polyurethane, polyphenylene sulfide, polyarylate, Polysulfone, polyethersulfone, polyetheretherketone, polyetherimide and the like can be mentioned. Prior to application, corona discharge treatment, plasma treatment, ozone treatment, flame treatment, primer (also called anchor coat, adhesion promoter, easy adhesive) application treatment, pre-heat treatment, dust removal treatment, vapor deposition treatment and alkali Easy adhesion treatment such as treatment may be performed. Moreover, you may add additives, such as a filler, a coloring agent, a plasticizer, and an antistatic agent, as needed.

The UV wavelength applied to cure all or a part of the unsaturated groups of the polymer (A) having an unsaturated group using a UV curing system or an EV curing system is 200 to 450 nm. A line acceleration voltage of 50-300 kV is used. In the production of the gas barrier film of the present invention, UV irradiation or EB irradiation is performed under conditions of exposure amount and time necessary for curing all or part of unsaturated groups in the polymer (A) layer having unsaturated groups. Is adopted. Specifically, the UV integrated exposure amount may be 500 to 5000 mJ / cm ² , and the EB integrated exposure amount may be 10 to 1000 kGy. Moreover, since oxygen inhibits radical polymerization reaction when oxygen is present, the irradiation atmosphere is preferably performed in nitrogen.

  When all or a part of the unsaturated group of the polymer (A) having an unsaturated group is cured using a UV curing system, a photopolymerization initiator is 0.1 to 0.1% of the resin content before film formation in advance. 10% is added, and after the coating film is formed, it is cured by using a UV curing system. In addition, when using EV curing system and all or a part of unsaturated group of the polymer (A) which has an unsaturated group hardens | cures, it may not be necessary to contain a photoinitiator.

  For curing all or part of the unsaturated groups of the polymer (A) having an unsaturated group, the photopolymerization initiator may be either a radical photopolymerization initiator or a photocationic polymerization initiator. Examples of the photo radical polymerization initiator used at this time include alkylphenone photopolymerization initiators, acylphosphine oxide photopolymerization initiators, titanocene photopolymerization initiators, and the like. Examples thereof include triarylsulfonium salts and diaryliodonium salts. In addition, these can be used 1 type or in mixture of 2 or more types, You may use a well-known hardening accelerator together.

  Various additives can be blended with the gas barrier coating agent of the present invention containing the polymer (A) having an unsaturated group depending on the physical properties to be imparted to the gas barrier layer. Specific examples of additives include a weather resistance improver, an abrasion resistance improver, a polymerization inhibitor, a crosslinking agent, an infrared absorber, an antistatic agent, an adhesion improver, a leveling agent, a thixotropic agent, and a coupling agent. , Plasticizers, antifoaming agents, fillers, solvents and coloring materials. In addition, as a weather resistance improving agent, hindered amine light stabilizers, such as HALS, a ultraviolet absorber, antioxidant, etc. can be used in the range which does not inhibit photocurability.

  Next, the present invention will be described more specifically with specific production examples, examples and comparative examples, but the present invention is not limited to these examples. In the following examples, “part” and “%” are based on mass unless otherwise specified.

[Production Example 1: Synthesis of cyclic carbonate-containing compound (CI)]
100 parts of bisphenol A type epoxy resin having an epoxy equivalent of 187 (trade name: Epototo YD-128, Nippon Steel & Sumikin Chemical Co., Ltd.), 20 parts of sodium iodide (Wako Pure Chemical Industries, Ltd.), and N-methyl-2-pyrrolidone 150 parts were charged into a reaction vessel equipped with a stirrer and a refluxer with an atmosphere opening. Subsequently, carbon dioxide was continuously blown in with stirring, and the reaction was performed at 100 ° C. for 10 hours. And 300 parts of water was added to the solution after completion | finish of reaction, the product was deposited, and it filtered. The obtained white powder was recrystallized from toluene to obtain 52 parts of white powder (yield 42%).

When the compound obtained above was analyzed by IR (IRAffinty-1 manufactured by Shimadzu Corporation), the absorption (peak) derived from the epoxy group of the raw material in the vicinity of 910 cm ⁻¹ disappeared, and the vicinity of 1800 cm ⁻¹ In addition, absorption (peak) derived from a carbonyl group of a carbonate group that does not exist in the raw material was confirmed. In addition, as a result of analysis by HPLC (manufactured by JASCO Corporation, LC-2000; column FinePakSIL C18-T5; mobile phase acetonitrile + water), the peak of the raw material disappeared, and a new peak appeared on the high polarity side. The purity was 98%. As a result of DSC measurement (differential scanning calorimetry), the melting point was 178 ° C., and the melting point range was ± 5 ° C. From the above, this powder was confirmed to be a compound having a structure represented by the following formula into which a cyclic carbonate group was introduced by the reaction of an epoxy group and carbon dioxide. This was abbreviated as compound (CI). The proportion of the component derived from carbon dioxide in this compound (CI) was 20.6% (calculated from the molecular weight in the chemical structural formula).

[Production Example 2: Synthesis of cyclic carbonate-containing compound (C-II)]
100 parts of hexanediol polyglycidyl ether (trade name: Epogosay HD (D), Yokkaichi Synthesis Co., Ltd.) with an epoxy equivalent of 116, 20 parts of sodium iodide (Wako Pure Chemical Industries, Ltd.), and N-methyl-2-pyrrolidone 150 parts were charged into a reaction vessel equipped with a stirrer and a refluxer with an atmosphere opening. Subsequently, carbon dioxide was continuously blown in with stirring, and the reaction was performed at 100 ° C. for 10 hours. And 400 parts of ethyl acetate and 800 parts of water were added to the solution after completion | finish of reaction, and it stirred for 1 hour. Thereafter, the ethyl acetate phase was recovered, and the solvent was removed by an evaporator to obtain 127 parts (yield 92.1%) of an oily compound.

When the compound obtained above was analyzed by IR, the absorption (peak) derived from the epoxy group of the raw material in the vicinity of 910 cm ⁻¹ disappeared, while the carbonate group not present in the raw material in the vicinity of 1800 cm ^−1. The absorption (peak) derived from the carbonyl group was confirmed. As a result of GPC measurement using DMF (dimethylformamide) as a mobile phase, the weight average molecular weight of the obtained substance was 318 (in terms of polyethylene oxide). From the above, this substance was confirmed to be a compound having a structure represented by the following formula in which a 5-membered cyclic carbonate group was introduced by the reaction of an epoxy group and carbon dioxide. This was abbreviated as (C-II). The proportion of the component derived from carbon dioxide in this compound (C-II) was 27.5% (calculated from the molecular weight in the chemical structural formula).

[Example 1]
In a reaction vessel equipped with a stirrer and a reflux opening having an air opening, 42.8 parts of the cyclic carbonate-containing compound (CI) obtained in Production Example 1 and hexamethylenediamine (Asahi Kasei Chemicals Corporation) 11. 6 parts and 81.6 parts of tetrahydrofuran as a reaction solvent were further added, and the reaction was carried out for 24 hours while stirring at a temperature of 60 ° C. A part of the solution after the reaction was sampled and analyzed by IR, and it was confirmed that absorption (peak) derived from the carbonyl group of the carbonate group in the vicinity of 1800 cm ⁻¹ disappeared. Subsequently, 3.1 parts of 2-methacryloyloxyethyl isocyanate (trade name: Karenz MOI, Showa Denko KK) and 0.01 part of p-methoxyphenol as a polymerization inhibitor are added to the solution after the above reaction, and 60 ° C. The reaction was conducted for 5 hours with stirring at a temperature of 5 ° C. Then, by sampling a part of the solution after the reaction again and analyzing by IR, it is confirmed that the absorption (peak) derived from the isocyanate group in the vicinity of 2300 cm ⁻¹ has disappeared, and is defined in the present invention. An unsaturated group-containing polyhydroxyurethane resin having a structure was synthesized. When the hydroxyl value of the obtained resin solution was measured, it was 176 mgKOH / g based on the resin content. The unsaturated group content was 0.3 meq / g, and the proportion of carbon dioxide-derived —O—CO— bonds in the resin content was 15.3% (from the molecular weight in the chemical structural formula). Calculated value).

0.8 parts of a photopolymerization initiator (trade name: Irgacure 184, Ciba Specialty Chemicals Co., Ltd.) is added to 100 parts of the resin solution obtained above, and the total solid content is added with Tetrohydrofuran. A coating liquid (gas barrier coating agent) was prepared by diluting to 40%. Then, the coating liquid prepared above is uniformly applied by a bar coating method to a corona-treated PET film having a thickness of 25 μm as a substrate so that the dry film thickness becomes 20 μm, and dried at 40 ° C. for 5 minutes. Then, it was cured with an integrated light quantity of 1200 mJ / cm ² with a metal halide lamp of 80 W / cm in a nitrogen atmosphere to form a crosslinked coating film (crosslinked resin film). As a result of measuring IR of the formed crosslinked coating film by ATR method (Shimadzu Corporation MIRacle 10), it was confirmed that there was almost no absorption derived from a double bond in the vicinity of 1637 cm ⁻¹ . FIG. 1 shows the IR spectrum of the crosslinked coating film. An evaluation sample described below was evaluated by using an evaluation sample as a cross-linked coating film formed on the substrate obtained above.

[Example 2]
An unsaturated group-containing polyhydroxyurethane resin having a structure defined in the present invention was synthesized in the same manner as in Example 1 except that the amount of 2-methacryloyloxyethyl isocyanate used in Example 1 was changed to 9.3 parts. did. The obtained resin had a hydroxyl value of 123 mgKOH / g based on the resin content. The unsaturated group content at this time is 0.9 meq / g, and the proportion of the carbon dioxide-derived —O—CO— bond in the resin content is 13.8% (calculated from the molecular weight in the chemical structural formula). Value). And after preparing a coating liquid (gas barrier coating agent) like Example 1 using the obtained resin solution, a crosslinked coating film is formed on a base material like Example 1. An evaluation sample was prepared.

[Example 3]
An unsaturated group-containing polyhydroxyurethane resin having a structure defined in the present invention was synthesized in the same manner as in Example 1 except that the amount of 2-methacryloyloxyethyl isocyanate used in Example 1 was changed to 27.9 parts. did. The obtained resin had a hydroxyl value of 14 mgKOH / g based on the resin content. At this time, the content of unsaturated groups was 2.2 meq / g, and the proportion of carbon dioxide-derived —O—CO— bonds in the resin content was 10.7% (calculation from molecular weight in chemical structural formula). Value). And after preparing a coating liquid (gas barrier coating agent) like Example 1 using the obtained resin solution, a crosslinked coating film is formed on a base material like Example 1. An evaluation sample was prepared.

[Example 4]
In place of 2-methacryloyloxyethyl isocyanate used in Example 1 and 8.5 parts of 2-acryloyloxyethyl isocyanate (trade name: Karenz AOI, Showa Denko KK), the same procedure as in Example 1 was performed. Thus, a polyhydroxyurethane resin having a structure defined in the present invention was synthesized. The obtained resin had a hydroxyl value of 125 mgKOH / g based on the resin content. The unsaturated group content at this time was 1.0 meq / g, and the proportion of carbon dioxide-derived —O—CO— bonds in the resin content was 14.0% (calculated from the molecular weight in the chemical structural formula). Value). And after preparing a coating liquid (gas barrier coating agent) like Example 1 using the obtained resin solution, a crosslinked coating film is formed on a base material like Example 1. An evaluation sample was prepared. FIG. 2 shows the IR spectrum of the crosslinked coating film formed in this example.

[Example 5]
32.0 parts of the compound (C-II) obtained in Production Example 2 and 13.6 parts of metaxylenediamine (Mitsubishi Gas Chemical Co., Ltd.) are placed in a reaction vessel equipped with a stirrer and a refluxing device having an air opening. Further, 68.4 parts of tetrahydrofuran was added as a reaction solvent, and the reaction was carried out for 24 hours while stirring at a temperature of 60 ° C. A part of the solution after the reaction was sampled and analyzed by IR, and it was confirmed that absorption (peak) derived from the carbonyl group of the carbonate group in the vicinity of 1800 cm ⁻¹ disappeared. Next, 27.9 parts of 2-methacryloyloxyethyl isocyanate similar to that used in Example 1 and 0.01 part of p-methoxyphenol as a polymerization inhibitor were added to the solution after the above reaction, The reaction was carried out for 5 hours while stirring at a temperature to synthesize an unsaturated group-containing polyhydroxyurethane resin having a structure defined in the present invention. When the hydroxyl value of the obtained resin solution was measured, it was 15 mgKOH / g with respect to the resin content. The unsaturated group content was 2.4 meq / g, and the proportion of carbon dioxide-derived —O—CO— bonds in the resin content was 12.0% (calculated from the molecular weight in the chemical structural formula). Is).

0.8 parts of a photopolymerization initiator (trade name: Irgacure, Ciba Specialty Chemicals Co., Ltd.) is added to 100 parts of the resin solution obtained above, and the total solid content is 40% with Tetrohydrofuran. It diluted so that it might become, and the coating liquid (coating agent) was prepared. Then, the coating liquid prepared above is uniformly applied by a bar coating method to a corona-treated PET film having a thickness of 25 μm as a substrate so that the dry film thickness becomes 20 μm, and dried at 40 ° C. for 5 minutes. After that, it was cured with an integrated light amount of 1200 mJ / cm ² with a metal halide lamp of 80 W / cm in a nitrogen atmosphere. As a result of measuring the IR of the crosslinked coating film in the same manner as in Example 1, it was confirmed that there was almost no absorption derived from a double bond in the vicinity of 1637 cm ⁻¹ , and this was used as an evaluation sample. FIG. 3 shows the IR spectrum of the crosslinked coating film obtained above.

[Example 6]
The same procedure as in Example 5 was conducted except that 2-acryloyloxyethyl isocyanate (trade name: Karenz AOI, Showa Denko KK) was changed to 2.8 parts instead of 2-methacryloyloxyethyl isocyanate used in Example 5. Thus, an unsaturated group-containing polyhydroxyurethane resin having a structure defined in the present invention was synthesized. The obtained resin had a hydroxyl value of 209 mgKOH / g based on the resin content. At this time, the content of unsaturated groups was 0.4 meq / g, and the proportion of carbon dioxide-derived —O—CO— bonds in the resin content was 18.2% (calculation from molecular weight in chemical structural formula). Value). And after preparing a coating liquid (gas barrier coating agent) like Example 1 using the obtained resin solution, a crosslinked coating film is formed on a base material like Example 1. An evaluation sample was prepared.

[Comparative Example 1]
In a reaction vessel equipped with a stirrer and a reflux opening having an air opening, 42.8 parts of the compound (CI) obtained in Production Example 1, 11.6 parts of hexamethylenediamine, and tetrahydrofuran as a reaction solvent. 81.6 parts was added and reacted for 24 hours while stirring at a temperature of 60 ° C. A part of the solution after the reaction was sampled and analyzed by IR, and it was confirmed that absorption (peak) derived from the carbonyl group of the carbonate group in the vicinity of 1800 cm ⁻¹ disappeared. Moreover, when the hydroxyl value was measured, it was 206 mgKOH / g with respect to the resin content. The unsaturated group was not contained, and the proportion of the carbon dioxide-derived —O—CO— bond in the resin content was 16.2% (calculated from the molecular weight in the chemical structural formula).

  The resin solution containing polyhydroxyurethane not containing unsaturated groups obtained above was diluted with tetrohydrofuran so that the total solid content was 40% to prepare a coating solution. Then, the coating liquid prepared above is uniformly applied by a bar coating method to a corona-treated PET film having a thickness of 25 μm as a substrate so that the dry film thickness becomes 20 μm, and dried at 40 ° C. for 5 minutes. Thus, a comparative evaluation sample in which a dry coating film was formed on a substrate was prepared.

[Comparative Example 2]
In a reaction vessel equipped with a stirrer and a reflux opening having an air opening, 42.8 parts of the compound (CI) obtained in Production Example 1, 11.6 parts of hexamethylenediamine, and tetrahydrofuran as a reaction solvent. 81.6 parts was added and reacted for 24 hours while stirring at a temperature of 60 ° C. A part of the solution after the reaction was sampled and analyzed by IR, and it was confirmed that absorption (peak) derived from the carbonyl group of the carbonate group in the vicinity of 1800 cm ⁻¹ disappeared. Next, 3.1 parts of 2-methacryloyloxyethyl isocyanate similar to that used in Example 1 and 0.01 part of p-methoxyphenol as a polymerization inhibitor were added and reacted at 60 ° C. with stirring for 5 hours. Thus, a polyhydroxyurethane resin containing an unsaturated group was synthesized. When the hydroxyl value of the obtained resin solution was measured, it was 176 mgKOH / g based on the resin content. The unsaturated group content was 0.3 meq / g, and the proportion of carbon dioxide-derived —O—CO— bonds in the resin content was 15.3% (calculated value from molecular weight in chemical structural formula). Is).

  The resin solution obtained above was diluted with tetrohydrofuran so that the total solid content was 40% to prepare a coating solution. Then, the coating liquid prepared above was uniformly applied to the corona-treated PET film having a thickness of 25 μm as a base material by a bar coating method so that the dry film thickness was 20 μm, and dried at 40 ° C. for 5 minutes. A comparative evaluation sample in which a dry coating film was formed on a substrate was used.

[Comparative Example 3]
In a reaction vessel equipped with a stirrer and a reflux opening having an air opening, 42.8 parts of the compound (CI) obtained in Production Example 1, 11.6 parts of hexamethylenediamine, and tetrahydrofuran as a reaction solvent. 81.6 parts was added and reacted for 24 hours while stirring at a temperature of 60 ° C. A part of the solution after the reaction was sampled and analyzed by IR, and it was confirmed that absorption (peak) derived from the carbonyl group of the carbonate group in the vicinity of 1800 cm ⁻¹ disappeared. Next, 3.1 parts of octyl isocyanate (Chuo Kasei Co., Ltd.) and 0.01 part of p-methoxyphenol as a polymerization inhibitor were added and reacted for 5 hours with stirring at a temperature of 60 ° C. Was synthesized with a polyhydroxyurethane resin substituted with an octyl group of a saturated hydrocarbon. When the hydroxyl value of the obtained resin solution was measured, it was 176 mgKOH / g based on the resin content. Moreover, this resin did not contain an unsaturated group, and the proportion of the carbon dioxide-derived —O—CO— bond in the resin component was 15.3% (calculated from the molecular weight in the chemical structural formula). is there).

  The polyhydroxyurethane resin containing no unsaturated groups obtained above was diluted with tetrohydrofuran so that the total solid content was 40% to prepare a comparative coating solution. Then, the coating liquid prepared above is uniformly applied by a bar coating method to a corona-treated PET film having a thickness of 25 μm as a substrate so that the dry film thickness becomes 20 μm, and dried at 40 ° C. for 5 minutes. A comparative evaluation sample in which a dry coating film was formed on a substrate was used.

[Comparative Example 4]
32.0 parts of the compound (C-II) obtained in Production Example 2, 13.6 parts of metaxylenediamine, and tetrahydrofuran as a reaction solvent in a reaction vessel equipped with a stirrer and a reflux vessel with an open air port. 68.4 parts was added and reacted for 24 hours while stirring at a temperature of 60 ° C. By sampling a part of the solution after the reaction and analyzing by IR, it was confirmed that absorption (peak) derived from the carbonyl group of the carbonate group in the vicinity of 1800 cm ⁻¹ disappeared. Moreover, when the hydroxyl value was measured, it was 246 mgKOH / g with respect to the resin content. This resin did not contain an unsaturated group, and the proportion of carbon dioxide-derived —O—CO— bonds in the resin content was 19.3% (calculated from the molecular weight in the chemical structural formula). .

  The resin solution obtained above was diluted with tetrohydrofuran so that the total solid content was 40% to prepare a coating solution. Then, the coating liquid prepared above is uniformly applied by a bar coating method to a corona-treated PET film having a thickness of 25 μm as a substrate so that the dry film thickness becomes 20 μm, and dried at 40 ° C. for 5 minutes. A comparative evaluation sample in which a dry coating film was formed on a substrate was used.

  In Table 1, the raw material composition of the polyhydroxyurethane resin used in the above-mentioned Examples and Comparative Examples is described in a mass ratio, and in the table, the hydroxyl value relative to the resin content after synthesis, the resin chemical structure after synthesis The mass per unsaturated group calculated from the above and the ratio of carbon dioxide-derived —O—CO— to the resin molecular weight are shown together.

<Measurement method>
The hydroxyl value, unsaturated group content, and CO ₂ content of Examples and Comparative Examples were measured as follows.

(Hydroxyl value)
As the hydroxyl value, a value measured according to the measuring method of JIS K1557-1 is described. The unit is mgKOH / g.

(Unsaturated group content)
The unsaturated group content was calculated and described as an unsaturated group equivalent per unit mass of the solid composition. The unit is meq / g. For example, in the case of Example 1, the content of unsaturated groups of Karenz MOI, which is the isocyanate used, is 1000 ÷ 155 = 6.5 meq / g. From this, the unsaturation in the solid composition obtained in Example 1 is The content of the saturated group is 6.5 × 3.1 parts ÷ (57.6 total amount) = 0.3 meq / g.

(CO ₂ content)
The content of CO ₂ was calculated and described as the ratio of the carbon dioxide-derived —O—CO— to the compound molecular weight. Specifically, the theory of carbon dioxide contained in the monomer used in synthesizing the compound (CI) or (C-II) used in the synthesis reaction of the polyhydroxyurethane resin having an unsaturated group. The calculated value calculated from the amount is shown. For example, in the case of Example 1, the component derived from carbon dioxide of the used compound (CI) was 20.6%, and the concentration of carbon dioxide in the solid composition of the solution obtained in Example 1 was 42.8 parts × 20.6%) / 57.5 total amount = 15.3 mass%.

<Evaluation method for evaluation sample>
Each evaluation sample in which a crosslinked coating film was formed on the substrate obtained in Examples 1 to 6 above and a comparative example in which a dry coating film was formed on the substrate obtained in Comparative Examples 1 to 4 above For each of the evaluation samples, the following items were evaluated by the following evaluation method. The results are summarized in Table 2 and Table 3.

[Oxygen permeability]
About each film, the transmittance | permeability of oxygen was measured based on JISK7126, and this was made into gas barrier property evaluation. It can be judged that the lower the value, the better the gas barrier property. Specifically, using an oxygen transmission rate measuring device (manufactured by MOCON, OX-TRAN2 / 21ML), the oxygen transmission rate of each film and the PET film used as the base material was adjusted to 23 ° C. relative humidity 65% (65 % Oxygen permeability) and a relative humidity of 90% (90% oxygen permeability) at 23 ° C. to measure oxygen permeability. The oxygen permeability of the gas barrier layer is a value calculated from the measured value in consideration of the amount corresponding to the oxygen permeability of the substrate. The unit is ml / m ² · day · atm, and the value exceeding 500 ml / m ² · day · atm is described as> 500. It can be evaluated that it is a coating layer excellent in gas barrier property, so that the described value is small.

[Humidity dependency]
Humidity dependence was quantified by the following calculation method. It can be judged that the smaller this value is, the less the humidity dependency is and the better the gas barrier property under high humidity. The object of the present invention is to make this humidity dependence value extremely close to zero.
(Humidity dependency) = (Oxygen permeability at 90% relative humidity) − (Oxygen permeability at 65% relative humidity)

[Strength at break]
The mechanical strength of each film was evaluated by the strength at break (tensile test). The breaking strength was evaluated in accordance with JIS K-7127 by measuring the breaking strength at room temperature (25 ° C.) by a measurement method using an autograph (manufactured by Shimadzu Corporation, AGS-J). .

  As shown in Table 3, in the same manner as in Example 1, the coating of Comparative Example 2 using a resin modified by substituting a part of the hydroxyl group of a polyhydroxyurethane resin using an isocyanate compound having an unsaturated group Even if it is an agent, in the case of a mere dry coating film that has not been cured by ultraviolet rays, both oxygen permeability at 65% relative humidity and 90% relative humidity is bad, and high gas barrier properties that are not dependent on humidity cannot be realized. It was confirmed. Similarly, when using the coating agent of Comparative Example 3 using a resin modified by substituting a part of the hydroxyl group of the polyhydroxyurethane resin using an octyl isocyanate compound having no unsaturated group, The dry coating film had poor oxygen permeability at a relative humidity of 65% and a relative humidity of 90%, and could not realize high gas barrier properties.

  In contrast, in Examples 1 to 6 in which a part of the hydroxyl group of the polyhydroxyurethane resin was modified using an isocyanate compound having an unsaturated group, and the modified unsaturated group was polymerized using ultraviolet rays. In this case, compared with Comparative Examples 1 and 4 in which the hydroxyl group of the polyhydroxyurethane resin is not modified, there is almost no change in oxygen permeability even at a relative humidity of 65% and a relative humidity of 90%. It was confirmed that there was no humidity dependence and high gas barrier properties could be maintained. Because gas barrier films are used for containers for pharmaceuticals and foods with extremely high demands for maintaining the quality of stored items, it was possible to maintain the high gas barrier properties shown in the films of the examples without dependence on humidity. , It has great significance in improving the performance of these products (containers).

  In addition to the above, it is possible to improve the performance of mechanical properties and thermal properties by polymerizing unsaturated groups derived from isocyanate compounds. As the amount of modification increases, the oxygen permeability at 65% relative humidity tends to increase, so finding the optimal amount of modification according to the application provides a more optimal functional film according to the application. It is considered effective to make this possible.

  As described above, according to the present invention, by using a polyhydroxyurethane resin, which is a resin that can use carbon dioxide as a raw material, there is almost no deterioration in gas barrier property, particularly under high humidity, and the humidity dependency of gas barrier property is present. In addition, a gas barrier film excellent in strength can be obtained, and its practicality is further improved, and its use is expected from the viewpoint of protecting the global environment.

Claims (5)

A gas barrier coating agent comprising an unsaturated group-containing polyhydroxyurethane resin, which is cured by ultraviolet rays or electron beams to form a crosslinked resin film,
The unsaturated group-containing polyhydroxyurethane resin is a repeating unit represented by the following general formula (1), wherein a part of the hydroxyl group is substituted with a group having an unsaturated group represented by the following general formula (5). A gas barrier coating agent characterized by comprising:

[X in the general formula (1) are fat-aliphatic hydrocarbons, show the chemical structure derived from a monomer unit composed of an alicyclic hydrocarbon or an aromatic hydrocarbon, in the structure, an oxygen atom, a nitrogen atom , May contain a sulfur atom or an ester bond. Y ₁ represents either a chemical structure having a hydroxyl group of the following formula (2) or (4), Y ₂ represents either a chemical structure having a hydroxyl group of the following formula (2) or (3), Repeating units having different combinations of Y ₁ and Y ₂ may be mixed. Furthermore, it is required that a part of the hydroxyl groups in Y ₁ and Y ₂ is substituted with a group having an unsaturated group of the following general formula (5). Z is alicyclic aliphatic hydrocarbons, show the chemical structure derived from a monomer unit composed of an alicyclic hydrocarbon or aromatic hydrocarbon may contain an oxygen atom, a nitrogen atom or a sulfur atom in the structure. ]

[In Formula (5), R < ₁ > is a C1-C10 alkylene group, and may contain the oxygen atom. R ₂ is a hydrogen atom or a methyl group. n is 1 or 2. ]   The unsaturated group content of the unsaturated group-containing polyhydroxyurethane resin is in the range of 0.3 meq / g to 2.5 meq / g, and the hydroxyl value is in the range of 10 mgKOH / g to 250 mgKOH / g. Item 2. The gas barrier coating agent according to Item 1.   The unsaturated group-containing polyhydroxyurethane resin was synthesized using carbon dioxide as one of raw materials, a compound having two 5-membered cyclic carbonate structures in one molecule, and two amino groups in one molecule 1 to 30% by mass of the mass of the coating layer formed by the unsaturated group-containing polyhydroxyurethane resin is obtained by a polyaddition reaction with a compound having a -O- The gas barrier coating agent according to claim 1 or 2, wherein the CO-bonding occupies.   The film is a gas barrier film in which the film is composed of a single layer or multiple layers, and at least one layer constituting the film is a layer having gas barrier properties, and the layer having gas barrier properties is any one of claims 1 to 3. A gas barrier film, which is a crosslinked resin film layer formed by irradiating the gas barrier coating agent according to the item with ultraviolet rays or electron beams. The gas barrier layer has a thickness of 0.1 to 100 μm, and the film has an oxygen permeability of 50 ml / m at a constant temperature and humidity of 23 ° C. relative humidity 65% and 23 ° C. relative humidity 90%. The gas barrier film according to claim 4, which is ² · 24 h · atm or less.

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