JP4626329B2 - Retort laminate - Google Patents

Description

  The present invention relates to a transparent barrier material having hot water resistance used in fields requiring heat treatment (retort treatment) with high-temperature and high-pressure water such as foods and pharmaceuticals.

  In recent years, packaging materials used for packaging foods and pharmaceuticals are made of oxygen, water vapor, or other gas that alters the contents, which permeates the packaging materials, in order to suppress the alteration of the contents and maintain their functions and properties. It is necessary to prevent the influence, and it is required to have a gas barrier property or the like for blocking these. Therefore, conventionally, a packaging material using a metal foil such as aluminum, which is less affected by temperature and humidity, as a gas barrier layer has been generally used.

  However, packaging materials that use metal foils such as aluminum are not affected by temperature and humidity and have excellent gas barrier properties, but have the disadvantage that they must be treated as non-combustible materials when discarded after use. There was a problem.

    Therefore, as a packaging material overcoming these drawbacks, a vapor deposition film of a metal such as aluminum, an inorganic oxide such as silicon oxide or aluminum oxide was formed on a polymer film by a forming means such as a vacuum vapor deposition method or a sputtering method. A film has been developed. These vapor-deposited films are known to have gas barrier properties such as oxygen and water vapor, and are suitable as packaging materials.

  In addition, foods and pharmaceuticals are increasingly required to be sterilized such as retort treatment, and a packaging material capable of maintaining performance under high temperature and high pressure is desired.

  In view of safety and convenience, there is a strong demand for transparent heat-resistant water barrier packaging materials.

  However, if the packaging material is to be realized using a conventional transparent vapor deposition film, the adhesion and gas barrier properties after retort sterilization cannot be maintained. As the cause, it is considered that the adhesion between the transparent vapor deposition film and the substrate is poor, the hot water resistance of the transparent vapor deposition film is low, and the barrier property cannot be maintained.

  The deterioration of adhesion is caused by the fact that aluminum oxide is deposited on the weak surface bonding layer (Weak Boundary Layer (WBL)) that is unevenly distributed on the outermost surface of the base material or on the hydrolysis layer in the case of PET. Therefore, it is considered that a chemical bond sufficient for water resistance is not obtained.

  It is considered that the deterioration of the gas barrier properties originates from the introduction of cracks in the deposited film due to the load (retort impact) on the deposited aluminum oxide film induced by the retort treatment.

  In order to solve the adhesion problem, an attempt has been made to improve the adhesion of metal oxide deposition on a plastic substrate by in-line pretreatment by using plasma in the past. The electrode for applying the voltage for generating the plasma is installed not on the drum side with the substrate but on the opposite side. In the case of this apparatus, since the base material is installed on the anode side, a high self-bias cannot be obtained, and as a result, a high treatment effect cannot be exhibited.

  In order to obtain a high self-bias, a DC discharge method can be used. However, if a high bias voltage is obtained by this method, the plasma mode changes from glow to arc, so a uniform treatment over a large area. Cannot be done.

Patent documents are as follows.
JP 2003-246000 A

  The present invention was made to solve the above-mentioned problems, and the performance deteriorates even during sterilization treatment such as retort treatment by strengthening the adhesion of the vapor deposition film and reducing the retort impact on the vapor deposition film. An object of the present invention is to provide a transparent gas barrier laminate.

In the invention according to claim 1, on a plastic substrate, a first inorganic filler-containing coating layer containing an inorganic filler 5 to 60 wt% is applied, further on the first inorganic filler-containing coating layer, the thickness An inorganic oxide vapor deposition layer having a thickness of 5 to 300 nm is provided , and on the inorganic oxide vapor deposition layer, at least one of a water-soluble polymer compound, a metal alkoxide and / or a hydrolyzate thereof, and / or a polymer thereof is a component. By providing a composite film layer having the above structure and further applying a second inorganic filler-containing film layer containing 5 to 60% by weight of an inorganic filler on the composite film layer. For retort that does not impair gas barrier properties even by heat treatment (retort treatment) with high-temperature and high-pressure water (maintained at 121 ° C., 2.45 × 10 5 Pa (gauge pressure) for 30 minutes) There is provided a lamina.

The invention according to claim 2 is characterized in that a pretreatment using reactive ion etching (RIE) mode plasma is performed on the resin undercoating surface before the vapor deposition step of the inorganic oxide vapor deposition layer. The laminated body for retorts of 1 is provided.

The invention according to claim 3 provides the laminate for retort according to claim 1 or 2 , wherein the inorganic filler is an inorganic pigment .

The invention according to claim 4 comprises at least one of the plastic substrate polyethylene, polypropylene, polyamides, polyesters, polycarbonate, polyacrylonitrile, polystyrene, polyvinyl chloride, cellulose, triacetyl cellulose, polyvinyl alcohol, and polyurethanes. The laminate for retort according to any one of claims 1 to 3, wherein the laminate is a component, a copolymer component, or a chemical modification thereof .

According to a fifth aspect of the present invention, the pretreatment by RIE is performed using one kind of gas of argon, nitrogen, oxygen, hydrogen, or a mixed gas thereof, or these gases or mixed gases are continuously used. The laminate for retort according to any one of claims 2 to 4, wherein the laminate for retort is provided.

According to a sixth aspect of the invention, pretreatment with the RIE is that a self-bias value is set to 200V or 2000V or less, also Ed = Ed values defined in plasma density × processing time 100V · s · m-2 or more 10000V The retort laminate according to any one of claims 2 to 5, which is a treatment with low-temperature plasma of s · m-2 or less .

The invention according to claim 7 is the retort according to any one of claims 2 to 6 , wherein the pretreatment and vapor deposition by the RIE are performed by the same film forming machine (in-line film forming machine). A laminated body is provided.

The invention according to claim 8 is the retort according to any one of claims 1 to 7 , wherein the water-soluble polymer compound has at least one of polyvinyl alcohol, cellulose and starch as a component. The laminated body for use is provided.

The invention according to claim 9 provides the laminate for retort according to any one of claims 1 to 8 , wherein the metal alkoxide is a silane alkoxide .

According to the above invention, the adhesion between the plastic substrate and the inorganic oxide vapor deposition layer is strengthened, and the inorganic oxide vapor deposition film is protected from the retort impact by the second inorganic filler-containing coating layer containing the inorganic filler. It is possible to provide a laminate for retort that does not deteriorate in performance even during heat treatment such as retort treatment.

  The action of suppressing the deterioration of adhesion is considered to be an effect of removing a layer that easily causes water-resistant deterioration, such as a resin surface weakly bonded layer (Weak Boundary Layer (WBL)) by RIE plasma. This provides a fresh surface to be deposited, which improves adhesion with aluminum oxide deposition and at the same time forms an interface that does not cause water-resistant degradation. As a mechanism to suppress deterioration due to gas barrier retort treatment, the impact on the vapor deposition film (retort impact) induced during hydrothermal treatment is absorbed and relaxed by the inorganic filler part, reducing the load on the vapor deposition film and vapor deposition. It is conceivable to prevent the introduction of cracks into the film and maintain the barrier property.

Therefore, in the laminate for retort of the present invention, an inorganic oxide vapor deposition layer that has been pretreated by RIE is formed on a substrate on which the first inorganic filler-containing coating layer has been applied, and the second layer is further formed thereon. by applying the inorganic filler-containing coating layer to form a sandwich structure of the inorganic oxide vapor deposition layer of an inorganic filler-containing coating layer, to prevent compression cracks due to shrinkage upon retort treatment, and the inorganic filler-containing coating layer / inorganic oxide It is possible to provide a laminate for retort that maintains the adhesion of the deposited object layer.

  In addition, this laminate can provide a packaging material with a wide range of practical use that is used for packaging foods and pharmaceuticals.

  Embodiments of the present invention will be described below.

FIG. 1 is a cross-sectional view illustrating a strong adhesion vapor deposition film of the present invention. On the surface of the plastic substrate 1, a first inorganic filler-containing coating layer 2, an inorganic oxide vapor deposition layer 3 pretreated by reactive ion etching (RIE) using plasma, a composite coating layer 4, a second coating layer 2 In this structure, the inorganic filler-containing coating layer 5 is formed. The first inorganic filler-containing coating layer 2, the inorganic oxide deposition layer 3, the composite coating layer 4, and the second inorganic filler-containing coating layer 5 may be formed on both sides of the substrate, or the composite coating layer 4 and the second A layer in which the components of the inorganic filler-containing coating layer 5 are mixed may be formed, or a multilayer may be used.

The plastic substrate 1 described above is a plastic material, and is preferably a transparent film substrate if possible in order to make use of the transparency of the inorganic oxide vapor deposition layer 3. Examples of substrates include polyester films such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyolefin films such as polyethylene and polypropylene, polystyrene films, polyamide films, polycarbonate films, polyacrylonitrile films, polyimide films and the like. Can be mentioned. Further examples include polyvinyl chloride, cellulose, triacetyl cellulose, polyvinyl alcohol, and polyurethanes. Materials having at least one or more of the above materials as components, having copolymer components, or having chemically modified compounds as components are also included. The substrate may be either stretched or unstretched, and preferably has mechanical strength and dimensional stability. Among these, a polyethylene terephthalate film or a polyamide film arbitrarily stretched in the biaxial direction is preferably used. Various known additives and stabilizers such as an antistatic agent, an ultraviolet ray inhibitor, a plasticizer, and a lubricant are used on the surface of the plastic substrate 1 opposite to the surface on which the inorganic oxide vapor deposition layer 3 is provided. May be.

The thickness of the plastic substrate 1 is not particularly limited, and a film obtained by laminating films having different properties other than a single film can be used in consideration of suitability as a packaging material. In consideration of workability in forming the first inorganic filler-containing coating layer 2 , the inorganic oxide vapor deposition layer 3 made of an inorganic oxide , and the composite coating layer 4 , a practical range of 3 to 200 μm is preferable. In particular, the thickness is preferably 6 to 30 μm.

Next will be described a first inorganic filler containing the layer 2. The first inorganic filler containing the film layer 2 is formed using a coating agent suitable formulations for film formation while include an inorganic filler. For example, an inorganic filler is kneaded with a resin component made of urethane or the like and mixed with an organic solvent in order to have a viscosity suitable for coating. After coating this solution on the inorganic oxide vapor deposition layer 3 which consists of an inorganic oxide , it heat-drys and forms. The inorganic filler component contained in the coating agent will be described in more detail.

  As the inorganic filler used in the present invention, an inorganic pigment is preferably used, and titanium oxide, calcium sulfate, calcium carbonate, barium sulfate and the like are particularly preferable. It is pulverized to be well dispersed in the coating solution. The weight percentage of the solution is preferably 5 to 60%, more preferably 10 to 25%. When the filler concentration is 5% or less, the effect of buffering the retort impact is insufficient. When the filler concentration is 60% or more, uniform dispersion cannot be achieved, and the coating itself is colored by the filler.

  As a method for applying the coating agent, conventionally known methods such as a dipping method, a roll coating method, a screen printing method, a spray method, and a gravure printing method that are usually used can be used.

The thickness of the first inorganic filler-containing coating layer 2 varies depending on the optimum conditions depending on the type of coating agent, the processing machine, and the processing conditions, and is not particularly limited. However, when the thickness after drying is 0.01 μm or less, a uniform coating film may not be obtained. On the other hand, if the thickness exceeds 50 μm, cracks are likely to occur in the film, which may be a problem. It is preferably in the range of 0.01 to 50 μm, more preferably in the range of 0.1 to 10 μm.

In order to reinforce the adhesion between the first inorganic filler-containing coating layer 2 and the metal or inorganic oxide deposition layer 3 , it is effective to perform a pretreatment by reactive ion etching (RIE) using plasma on the surface. is there. By performing this RIE process, the generated radicals and ions are used to provide a chemical effect such as giving a functional group to the surface of the resin layer, and the surface is ion-etched to remove or smooth impurities. It is possible to obtain two physical effects simultaneously. By performing such surface treatment, a dense thin film of an inorganic oxide can be formed in the subsequent vapor deposition. As a result, the adhesion between the first inorganic filler-containing coating layer 2 and the metal or inorganic oxide vapor deposition layer 3 can be strengthened, which not only leads to improved gas barrier properties and prevention of cracks, but also causes delamination. There is no.

  Argon, oxygen, nitrogen, and hydrogen can be used as the gas species for performing the pretreatment by RIE. These gases may be used alone, or two or more kinds of gases may be mixed and used. Moreover, you may process continuously using two processor.

The processing conditions indicated by the processing speed, energy level, and the like should be set as appropriate according to the type of substrate, application, discharge device characteristics, and the like. However, the self-bias value of the plasma 200V or 2000V or less, Ed = Ed values defined in plasma density × processing time is necessary to below 100V · s · m ^-2 higher 10000V · s · m ^-2 Even at a slightly lower value, a certain degree of adhesion is exhibited, but the superiority is lower than that of the untreated product. On the other hand, if the value is high, a strong treatment is applied excessively, the surface of the base material is deteriorated, and the adhesiveness is lowered. Regarding the gas for plasma and the mixing ratio thereof, the flow rate differs depending on the pump performance, the mounting position, and the like, so that the flow rate differs depending on the application, base material, and device characteristics.

In general, the thickness of the inorganic oxide deposition layer 3 is desirably in the range of 5 to 300 nm, and the value is appropriately selected. However, if the film thickness is less than 5 nm, a uniform film may not be obtained or the film thickness may not be sufficient, and the function as a gas barrier material may not be sufficiently achieved. Further, when the film thickness exceeds 300 nm, the thin film cannot be kept flexible, and there is a problem because the thin film may be cracked due to external factors such as bending and pulling after the film formation. More preferably, it exists in the range of 10-150 nm.

There are various methods for forming the inorganic oxide vapor-deposited layer 3 made of aluminum oxide on the plastic substrate 1 , and can be formed by a normal vacuum vapor deposition method. In addition, other thin film forming methods such as sputtering, ion plating, and plasma vapor deposition (CVD) can also be used. However, considering productivity, the vacuum deposition method is the best at present. As a heating means of the vacuum evaporation method, it is preferable to use any one of an electron beam heating method, a resistance heating method, and an induction heating method, but the electron beam heating method should be used in consideration of the wide selection of evaporation materials. Is more preferable. Moreover, in order to improve the adhesiveness of the inorganic oxide vapor deposition layer 3 and the plastic base material 1 , and the denseness of a vapor deposition thin film layer, it is also possible to vapor-deposit using a plasma assist method or an ion beam assist method.

  The pretreatment and vapor deposition by RIE may be performed by the same film forming machine (in-line film forming machine). By in-line film formation, the process can be shortened and an inexpensive film can be provided.

Next, the composite coating layer 4 will be described. The composite coating layer 4 is a coating layer having a gas barrier property, and is formed by using a coating agent mainly composed of an aqueous solution or water / alcohol mixed solution containing a water-soluble polymer and one or more metal alkoxides or hydrolysates thereof. Is done. For example, a solution obtained by mixing a water-soluble polymer dissolved in an aqueous (water or water / alcohol mixed) solvent with a metal alkoxide directly or previously hydrolyzed is used as a solution. After coating this solution on the inorganic oxide vapor deposition layer 3 which consists of a metal or an inorganic oxide , it heat-drys and forms. Each component contained in the coating agent will be described in more detail.

Examples of the water-soluble polymer used in the coating agent in the present invention include polyvinyl alcohol, polyvinyl pyrrolidone, starch, methyl cellulose, carboxymethyl cellulose, and sodium alginate. In particular, when polyvinyl alcohol (hereinafter abbreviated as PVA) is used for the coating agent of the present invention, the gas barrier property is most excellent, which is preferable. PVA here is generally obtained by saponifying polyvinyl acetate. As PVA, for example, complete PVA in which only several percent of acetic acid groups remain can be used from so-called partially saponified PVA in which several tens percent of acetic acid groups remain, and other types may be used. .

The metal alkoxide is a compound represented by a general formula, M (OR) _n (M: metal such as Si, Ti, Al, Zr, R: alkyl group such as CH ₃ , C ₂ H ₅ ). Specific examples include tetraethoxysilane [Si (OC ₂ H ₅ ) ₄ ] and triisopropoxyaluminum [Al (O-2′-C ₃ H ₇ ) ₃ ], among which tetraethoxysilane and triisopropoxy. Aluminum is preferable because it is relatively stable in an aqueous solvent after hydrolysis.

  In addition, since the composite film layer which consists of a mixture of a metal alkoxide and a water-soluble polymer consists of hydrogen bonds, it may swell and dissolve in water. In order to prevent this, it is preferable to add a silane coupling agent to the metal alkoxide.

  It is also possible to add known additives such as isocyanate compounds, silane coupling agents, or dispersants, stabilizers, viscosity modifiers, and colorants to the solution as long as the gas barrier properties are not impaired. is there.

  As a method for applying the coating agent, conventionally known methods such as a dipping method, a roll coating method, a screen printing method, a spray method, and a gravure printing method that are usually used can be used.

  The thickness of the composite coating layer varies depending on the optimum conditions depending on the type of coating agent, the processing machine and the processing conditions, and is not particularly limited. However, when the thickness after drying is 0.01 μm or less, a uniform coating film cannot be obtained and sufficient gas barrier properties may not be obtained. On the other hand, if the thickness exceeds 50 μm, cracks are likely to occur in the film, which may be a problem. It is preferably in the range of 0.01 to 50 μm, more preferably in the range of 0.1 to 10 μm.

Next will be described a second inorganic filler containing the layer 5. Second inorganic filler containing the film layer 5 is basically the same as the first inorganic filler containing the layer 2.

A printing layer, an intervening film, a sealant layer, and the like can be laminated on the second inorganic filler-containing coating layer 5 to obtain a packaging material.

  The intervening film is provided in order to increase the bag breaking strength and puncture strength at the time of the bag-shaped packaging material, and is generally a biaxially stretched nylon film, a biaxially stretched polyethylene terephthalate film, in terms of mechanical strength and thermal stability, It is necessary to be one selected from among biaxially stretched polypropylene films. The thickness is determined according to the material and required quality, but is generally in the range of 10 to 30 μm.

  Furthermore, the sealant layer is provided as an adhesive layer when forming a bag-like package. For example, polyethylene, polypropylene, ethylene-vinyl acetate copolymer, ethylene-methacrylic acid copolymer, ethylene-methacrylic acid ester copolymer, ethylene-acrylic acid copolymer, ethylene-acrylic acid ester copolymer and their metals A resin such as a cross-linked product is used. The thickness is determined according to the purpose, but is generally in the range of 15 to 200 μm.

  A printing layer, an intervening film, a sealant layer, and the like can be laminated on the opposite surface of the substrate 1 as necessary.

  Examples of the present invention will be specifically described below. The present invention is not limited to these examples.

A liquid A shown below was prepared on one side of a biaxially stretched polyethylene terephthalate (PET) film having a thickness of 12 μm, and applied and dried by a gravure coating method to form a first inorganic filler-containing coating layer having a thickness of 1 μm.

  Liquid A: A solution obtained by kneading urethane resin and barium sulfate and diluting with an organic solvent (isopropyl alcohol: methyl ethyl ketone: toluene = 1: 3: 2). The barium sulfate component ratio was 20 wt%.

Pretreatment by reactive ion etching (RIE) using plasma was performed on the first inorganic filler-containing coating layer. At this time, a high frequency power supply with a frequency of 13.56 MHz was used for the electrodes, the self-bias value was 800 V, and the Ed value was 450 V / s / m2. Argon / oxygen mixed gas was used as the processing gas. On top of this, an aluminum oxide film was formed to a thickness of 20 nm by reactive vapor deposition using an electron beam heating method to produce a vapor deposition film.

  On this vapor-deposited film, a solution in which the following B liquid and C liquid are mixed at a mixing ratio (wt%) of 6/4 is prepared, applied and dried by a gravure coating method, and a composite coating layer having a thickness of 0.4 μm Formed.

Liquid B: 89.6 g of hydrochloric acid (0.1N) was added to 10.4 g of tetraethoxysilane and stirred for 30 minutes to obtain a hydrolyzed solution having a solid content of 3 wt% (in terms of SiO ₂ ).

  Solution C: A 3 wt% water / isopropyl alcohol solution of polyvinyl alcohol (90:10 by weight of water: isopropyl alcohol).

Further the composite target film, Liquid A was coated and dried by gravure coating method to form a second inorganic filler-containing coating layer having a thickness of 1 [mu] m.

  Furthermore, a laminate sample of the above-mentioned vapor deposited film / stretched nylon (15 μm) / unstretched polypropylene (70 μm) was prepared by dry lamination using a two-component curable polyurethane adhesive.

<Evaluation 1>
Oxygen permeability after retort treatment ...
A four-sided pouch was prepared using the above laminated sample, and a sample filled with tap water as the contents was subjected to a hot water recovery type retort treatment.
Retorting, retorting device comprising a sterilizing kettle hot water tank, 130 ° C. from hot water tank, the hot water of 2.45 × 10 ⁵ Pa, the sterilizing kettle containing the shelves arranged sample 9.81 × 10 ⁴ was injected from above the sterilizing kettle while maintaining the Pa, pressure 1.96 × 10 ⁵ Pa, adjusting maintained for 30 minutes to 121 ° C. the temperature after holding, the cooling water while maintaining the pressure, Pour from the bottom of the sterilization pot, remove hot water from the top, replace and cool. After discharging the cooling water, the sample was taken out under reduced pressure.
After this treatment, water was extracted from the sample, and the oxygen permeability after the retort treatment of the laminated sample was measured using a modern control company (MOCON OXTRAN 10 / 50A) after the vapor deposition step in a 30 ° C.-70% RH atmosphere. Films were measured within 24 hours after retorting. The results are shown in Table 1.

<Evaluation 2>
Lamination strength after retort treatment ...
The laminate strength between the vapor deposited film and stretched nylon of the laminated sample after the above retort treatment was measured using an orientec Tensilon universal testing machine RTC-1250 (JIS).
Z1707 conformity). However, the measurement was performed while the measurement site was wetted with water. The results are shown in Table 1.

A laminated sample was produced in the same manner as in Example 1 except that the content ratio of the inorganic filler component was 10 wt%.

<Comparative Example 1>
A laminated sample was produced in the same manner as in Example 1 except that the first inorganic filler-containing coating layer and the second inorganic filler-containing coating layer were not applied.

The present invention relates to a laminate for retort having hot water resistance used in a field requiring heat treatment (retort treatment) with high-temperature and high-pressure water such as foods and pharmaceuticals.

It is sectional drawing of the strong adhesion vapor deposition film of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Plastic base material 2 ... Inorganic filler containing layer 3 ... Inorganic oxide vapor deposition layer 4 ... Composite coating layer 5 ... Inorganic filler containing layer 6 ... Pretreatment surface by RIE

Claims (9)

A first inorganic filler-containing coating layer containing 5 to 60% by weight of an inorganic filler is applied on a plastic substrate, and further , an inorganic oxide having a thickness of 5 to 300 nm is formed on the first inorganic filler-containing coating layer . A vapor deposition layer is provided , and a composite coating layer having at least one of a water-soluble polymer compound, a metal alkoxide and / or a hydrolyzate thereof, and a polymer thereof as a component is further provided on the inorganic oxide vapor deposition layer, Furthermore, the 2nd inorganic filler containing coating layer containing 5-60 weight% of inorganic fillers was apply | coated on the said composite coating layer, The laminated body for retorts characterized by the above-mentioned. Before the deposition process of the prior-inorganic oxide vapor deposition layer, to the resin undercoating surface, reactive ion etching (RIE) mode retort laminate according to claim 1, wherein performing a pre-process using plasma . The laminate for retort according to claim 1 , wherein the inorganic filler is an inorganic pigment. The plastic substrate has at least one of polyethylene, polypropylene, polyamides, polyesters, polycarbonate, polyacrylonitrile, polystyrene, polyvinyl chloride, cellulose, triacetyl cellulose, polyvinyl alcohol, polyurethane, or a copolymer component. The laminate for retort according to any one of claims 1 to 3, wherein the laminated body has a component or a chemically modified product thereof as a component. The pretreatment by RIE is a treatment performed using one kind of gas of argon, nitrogen, oxygen, hydrogen, or a mixed gas thereof, or continuously using these gases or a mixed gas. The laminate for retort according to any one of claims 2 to 4, wherein the laminate is for retorts. In the pretreatment by RIE, the self-bias value is set to 200 V or more and 2000 V or less, and the Ed value defined by Ed = plasma density × processing time is 100 V · s · m −2 to 10000 V · s · m −2. The laminate for retort according to any one of claims 2 to 5, wherein the laminate is a treatment with a certain low temperature plasma. The retort laminate according to any one of claims 2 to 6, wherein the pretreatment and vapor deposition by the RIE are performed by the same film forming machine (in-line film forming machine). The retort laminate according to any one of claims 1 to 7, wherein the water-soluble polymer compound has at least one of polyvinyl alcohol, cellulose, and starch as a component. The laminate for retort according to claim 1, wherein the metal alkoxide is a silane alkoxide.

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