JP7091679B2 - Retort food sealant film - Google Patents

Description

The present invention relates to a retort food sealant film having an excellent balance between low temperature impact resistance and high temperature heat resistance.

Demand for retort-packed foods is increasing due to lifestyle changes (increasing single-person households, individualized meals). Along with this, demand for retort-packed food packaging materials is also increasing. In particular, microwave oven-compatible pouches are growing rapidly. Further, there is a demand for packaging materials for retort foods suitable not only for storage at room temperature but also for low temperature distribution (frozen to chilled).
Examples of the structure of such a film include the following.
PET // Ny // PO vapor deposition PET // Ny // PO
* PO: PP or PE
Of these, the PO film is required to have heat sealability, low temperature impact resistance, transparency and the like. Generally, for freezing to chilled, it is preferable to select a polyethylene resin having excellent low temperature impact resistance.
Normally, in order to improve the heat resistance so that the polyethylene resin can be applied to retort high temperature sterilization, it is necessary to set a high density. However, in a general polyethylene single-layer film manufactured by using a high-density polyethylene resin, the low-temperature impact resistance is lowered. A decrease in low temperature impact resistance leads to a decrease in compressive strength and a decrease in drop strength, and causes a risk of leakage of contents during low temperature transportation.

For example, a packaging material film having a first layer containing a thermoplastic resin as a main resin on the outermost surface and a second layer and a third layer in this order following the first layer, wherein the first layer is provided. The thickness is 1 μm or more and 3 μm or less, the second layer is formed on one surface of the first layer, the resin density is lower than that of the first layer and the third layer, and the third layer is , A packaging material film characterized in that it is formed on the back surface of the surface of the second layer facing the first layer has been proposed. (Patent Document 1)
However, the above-mentioned film for packaging materials has a big problem that high temperature heat resistance is not sufficient. When the packaging material film is heat-pressurized and sterilized under the condition of 115 ° C., there is a problem that the film is fused.

JP-A-2017-177565

An object of the present invention is to provide a sealant film for retort foods having an excellent balance between low temperature impact resistance and high temperature heat resistance (corresponding to heat and pressure sterilization treatment in a semi-retort region (more than 110 ° C to less than 120 ° C)). be.

As a result of diligent studies to solve the above problems, the present inventors have found that the above problems can be solved by laminating them using a specific ethylene / α-olefin copolymer. Further studies were carried out on these findings, and the present invention was completed.
That is, according to the first invention of the present invention, it is a laminated body in which at least the first layer, the second layer and the third layer are laminated in this order, and the first layer contains the component (A) and the first layer is the first. A retort-packed sealant film comprising a laminate, wherein the second layer contains the component (B) and the third layer contains the component (C).
Component (A): Copolymer of ethylene having the following characteristics (A-i) to (A-ii) and α-olefin having 3 to 12 carbon atoms (A-i) Melt flow rate (190 ° C., 21) .18N load) is 0.1g / 10 minutes or more, 5.0g / 10 minutes or less (A-ii) Density is 0.915g / cm ³ or more, 0.930g / cm ³ or less Component (B): The following (B) -I) A copolymer of ethylene produced using a metallocene catalyst having the characteristics of (Bv) and an α-olefin having 3 to 12 carbon atoms (Bi) Melt flow rate (190 ° C., 21) .18N load) is 0.1 g / 10 minutes or more, 5.0 g / 10 minutes or less (B-ii) Density is 0.890 g / cm ³ or more, 0.925 g / cm ³ or less (B-iii) α-olefin Content is 5% by weight or more and 40% by weight or less (B-iv) The ratio (Mw / Mn) of the weight average molecular weight (Mw) and the number average molecular weight (Mn) determined by gel permeation chromatography (GPC). Is 1.0 or more and 4.0 or less (Bv) The maximum value of the melting peak temperature is 115 ° C or more and less than 130 ° C. Component (C): Has the following characteristics (C-i) to (C-ii). Copolymer of ethylene and α-olefin having 3 to 12 carbon atoms (Ci) Melt flow rate (190 ° C, 21.18N load) is 0.1 g / 10 minutes or more, 5.0 g / 10 minutes or less () C-ii) Density is 0.930 g / cm ³ or more, 0.950 g / cm ³ or less

According to the second invention of the present invention, in the first invention of the present invention, the first layer is composed of 70% by weight or more and 99% by weight or less of the component (A) and 1% by weight or more of the following component (D), 30. It is composed of an ethylene resin layer I containing% by weight or less, and the second layer contains 80% by weight or more of the component (B) and 99% by weight or less, and 1% by weight or more and 20% by weight or less of the following component (D). The third layer is an ethylene resin layer containing 70% by weight or more and 99% by weight or less of the component (C) and 1% by weight or more and 30% by weight or less of the following component (D). A retort food sealant film comprising III.
Component (D): High-pressure low-density polyethylene (D-i) melt flow rate (190 ° C., 21.18 N load) having the following characteristics (D-i) to (D-ii) is 0.1 g / 10 minutes. 5.0 g / 10 minutes or less (D-ii) Density is 0.915 g / cm ³ or more, 0.935 g / cm ³ or less

According to the third invention of the present invention, in the first invention or the second invention of the present invention, the first layer is composed of the component (A) of 80% by weight or more, 95% by weight or less, and the component (D) 5. It is composed of an ethylene resin layer I containing% by weight or more and 20% by weight or less, and the second layer is composed of 85% by weight or more and 95% by weight or less of the component (B) and 5% by weight or more and 15% by weight of the component (D). % Or less of the ethylene resin layer II, and the third layer is ethylene containing 80% by weight or more and 95% by weight or less of the component (C) and 5% by weight or more and 20% by weight or less of the component (D). It is a retort food sealant film characterized by being composed of a based resin layer III.

According to the fourth invention of the present invention, in any one of the first invention to the third invention of the present invention, the component (B) has the following characteristics (B-vi) and ethylene has 3 to 12 carbon atoms. A retort-packed sealant film, characterized by being an α-olefin copolymer of.
(B-vi) In the elution curve, the maximum value of the elution peak temperature is 85 ° C or higher and 100 ° C or lower.

According to the fifth invention of the present invention, in any one of the first invention to the fourth invention of the present invention, the surface of the first layer opposite to the second layer is subjected to corona treatment at the time of molding. A retort-packed food sealant film having a treated surface and a heat-sealed surface on the side opposite to the second layer of the third layer.

According to the sixth aspect of the present invention, the retort-packed food sealant film in which the substrate layer selected from PET, Ny, OPP, and AL is laminated on the treated surface side of the retort-packed food sealant film according to the fifth aspect of the present invention. Is.

According to the seventh aspect of the present invention, it is a pouch using the retort food sealant film according to the fifth aspect of the present invention.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a retort food sealant film having an excellent balance between low temperature impact resistance and high temperature heat resistance (corresponding to heat pressure sterilization treatment in a semi-retort region (more than 110 ° C to less than 120 ° C)).

Hereinafter, the retort-packed sealant film will be described in detail for each item.

The laminate of the present invention is a laminate in which at least the first layer, the second layer, and the third layer are laminated in this order, and the first layer and the third layer contain a specific ethylene / α-olefin copolymer. It is a retort food sealant film containing, and the second layer contains a specific ethylene / α-olefin copolymer produced by using a metallocene catalyst.

Preferably, the first layer is composed of an ethylene resin layer I containing a specific ethylene / α-olefin copolymer and a specific high pressure method low density polyethylene, and the second layer is manufactured by using a metallocene catalyst. It is composed of an ethylene resin layer II containing a specific ethylene / α-olefin copolymer and a specific high pressure method low density polyethylene, and a third layer is composed of a specific ethylene / α-olefin and a specific high pressure method low density polyethylene. It is a retort food sealant film composed of the ethylene-based resin layer III contained therein.

1. 1. First Layer The first layer of the laminate of the present invention may contain an ethylene / α-olefin copolymer (component (A)), but is preferably an ethylene / α-olefin copolymer (component (A)). )) It is composed of an ethylene resin layer I containing 70% by weight or more, 99% by weight or less, and 1% by weight or more and 30% by weight or less of high-pressure low-density polyethylene (component (D)).

(1) Ingredient (A)
The ethylene / α-olefin copolymer (component (A)) used for the first layer of the laminate of the present invention is a copolymer of ethylene and an α-olefin having 3 to 12 carbon atoms. The copolymer is an ethylene / α-olefin copolymer having the following characteristics (A-i) to (A-ii).
Hereinafter, the constituent monomers, the polymerization method, and the characteristics thereof will be sequentially described.

(A-i) Melt flow rate (MFR)
The MFR (190 ° C., 21.18 N load) of the component (A) used for the first layer of the laminate of the present invention is 0.1 g / 10 minutes or more and 5.0 g / 10 minutes or less, preferably 0. 1 g / 10 minutes or more, 4.5 g / 10 minutes or less, more preferably 0.5 g / 10 minutes or more to 3.0 g / 10 minutes or less, still more preferably 1.0 g / 10 minutes or more, 2. 5 g / 10 minutes or less. When the MFR of the component (A) is 0.1 g / 10 minutes or more, the resin pressure is low and the moldability is good, and when it is 5.0 g / 10 minutes or less, the bubbles become stable during inflation molding and molding is performed. It is preferable because the properties are good and there is no risk of exhibiting behavior inferior in heat resistance such as wrinkles on the sealant film after heat-pressurization sterilization treatment at more than 110 ° C to less than 120 ° C.
Here, the MFR of the ethylene / α-olefin copolymer of the component (A) is measured in accordance with JIS K6922-2: 1997 Annex (190 ° C., 21.18N load).

(A-ii) Density The density of the component (A) used in the first layer of the laminate of the present invention is 0.915 g / cm ³ or more, 0.930 g / cm ³ or less, preferably 0.917 g / cm ³ or more. , 0.925 g / cm ³ or less, more preferably 0.918 g / cm ³ or more, 0.923 g / cm ³ or less, still more preferably 0.919 g / cm ³ or more, 0.922 g / cm ³ or less. When the density of the component (A) is 0.915 g / cm ³ or more, there is no risk that the sealant film will melt after the heat-pressurization sterilization treatment of more than 110 ° C. to less than 120 ° C., and it is 0.930 g / cm ³ or less. This is preferable because there is no risk that the low-temperature impact resistance will decrease.
Here, the density of the ethylene / α-olefin copolymer of the component (A) is measured at 23 ° C. in accordance with JIS K6922-2: 1997 Annex (in the case of low density polyethylene).

It is preferable that the copolymer of ethylene of the component (A) and the α-olefin having 3 to 12 carbon atoms further has the following characteristics (A-iii) to (A-iv).

(A-iii) Monomer Composition The component (A) used in the first layer of the laminate of the present invention is a random copolymer of ethylene and α-olefin containing a structural unit derived from ethylene as a main component.
The α-olefin used as a comonomer is preferably an α-olefin having 3 to 12 carbon atoms. Specifically, propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-heptene, 4-methyl-pentene-1, 4-methyl-hexene-1, 4, 4-dimethylpentene- The first prize can be mentioned. Specific examples of such ethylene / α-olefin copolymers include ethylene / propylene copolymer, ethylene / 1-butene copolymer, ethylene / 1-hexene copolymer, ethylene / 1-octene copolymer, and ethylene. -Examples include 4-methyl-pentene-1 copolymer. Further, the α-olefin may be one kind or a combination of two or more kinds. When two kinds of α-olefins are combined into a terpolymer, examples thereof include ethylene / propylene / hexcentrpolymer, ethylene / butene / hexcentrpolymer, ethylene / propylene / octeneterpolymer, and ethylene / butene / octeneterpolymer. ..

(A-iv) Polymerization catalyst and polymerization method The component (A) used for the first layer of the laminate of the present invention can be produced by using a Ziegler catalyst, a vanadium catalyst, a metallocene catalyst, preferably a metallocene catalyst. Examples of the production method include a high-pressure ion polymerization method, a gas phase method, a solution method, and a slurry method.

(2) Component (D)
The high-pressure low-density polyethylene (component (D)) used for the first layer of the laminate of the present invention has the following characteristics (Di) to (D-ii).

(Di) Melt flow rate (MFR)
The MFR (190 ° C., 21.18 N load) of the component (D) used for the first layer of the laminate of the present invention is 0.1 g / 10 minutes or more and 5.0 g / 10 minutes or less, preferably 0. It is 5 g / 10 minutes or more and 4.0 g / 10 minutes or less, more preferably 0.7 g / 10 minutes or more and 3.0 g / 10 minutes or less. When the MFR of the component (D) is 0.1 g / 10 minutes or more, the resin pressure is low and the moldability is good, and when it is 5.0 g / 10 minutes or less, bubbles become unstable during inflation molding and the moldability is poor. It is preferable because there is no risk of becoming.
Here, the MFR of the high-pressure method low-density polyethylene of the component (D) is measured in accordance with JIS K6922-2: 1997 Annex (190 ° C., 21.18 N load).

(D-ii) Density The density of the component (D) used in the first layer of the laminate of the present invention is 0.915 g / cm ³ or more, 0.935 g / cm ³ or less, preferably 0.920 g / cm ³ or more. , 0.930 g / cm ³ or less, more preferably 0.923 g / cm ³ or more, 0.929 g / cm ³ or less. When the density of the component (D) is 0.915 g / cm ³ or more, there is no risk that the sealant film will melt after the heat-pressurization sterilization treatment of more than 110 ° C. to less than 120 ° C., and it is 0.935 g / cm ³ or less. This is preferable because there is no risk of deterioration in transparency.
Here, the density of the high-pressure method low-density polyethylene of the component (D) is measured at 23 ° C. in accordance with JIS K6922-2: 1997 Annex (in the case of low-density polyethylene).

(3) Other Additive Components The ethylene-based resin layer I of the present invention may contain other additional optional components as long as the effects of the present invention are not significantly impaired. Such optional components include antioxidants (particularly phenol-based and phosphorus-based antioxidants are preferable), antiblocking agents, neutralizing agents, heat stabilizers, and crystals used in ordinary polyethylene-based resin materials. Examples thereof include nucleating agents, clearing agents, lubricants, colorants, dispersants, peroxides, fillers, fluorescent whitening agents and the like.
Further, in order to impart flexibility, a rubber compound such as an ethylene / α-olefin elastomer such as EBR and EPR and a styrene elastomer such as SEBS and HSBR can be blended.

(4) Blending Ratio of Component (A) and Component (D) The ethylene-based resin layer I of the present invention may contain the component (A), but preferably contains the component (D). The blending ratio of the component (A) and the component (D) is preferably 70% by weight or more and 99% by weight or less of the component (A) and 1% by weight or more and 30% by weight or less of the component (D), preferably the component. (A) component (D) 5% by weight or more and 20% by weight or less with respect to 80% by weight or more and 95% by weight or less, and more preferably component (A) component (A) 80% by weight or more and 90% by weight or less. (D) 10% by weight or more and 20% by weight or less.
When the component (A) is contained, there is no possibility of exhibiting behavior inferior in heat resistance such as wrinkles on the sealant film after the heat and pressure sterilization treatment of more than 110 ° C. to less than 120 ° C., which is preferable.

(5) Method for Adjusting Ethylene Resin Layer I The component (A) and the component (D) contained in the ethylene resin layer I can be prepared by melt-kneading, if necessary.
More specifically, the component (A) and the component (D) may be dry-blended in advance, and the blend may be directly put into the hopper of the molding machine. Further, the blend may be melted and kneaded using an extruder, a lavender plastograph, a Banbury mixer, a kneader blender or the like, and pelletized by a commonly used method to produce a film or a sheet.

2. 2. Second layer The second layer of the laminate of the present invention may contain an ethylene / α-olefin copolymer (component (B)), but is preferably an ethylene / α-olefin copolymer (component (B)). )) It is composed of an ethylene resin layer II containing 80% by weight or more, 99% by weight or less, and 1% by weight or more and 20% by weight or less of high-pressure low-density polyethylene (component (D)).

(1) Ingredient (B)
The ethylene / α-olefin copolymer (component (B)) used for the second layer of the laminate of the present invention is a common weight of ethylene produced using a metallocene catalyst and an α-olefin having 3 to 12 carbon atoms. It is a coalescence. The copolymer is an ethylene / α-olefin copolymer having the following properties (Bi) to (Bv). It preferably has the property of (B-vi).
Hereinafter, the constituent monomers, the polymerization method, and the characteristics thereof will be sequentially described.

(Bi) Melt flow rate (MFR)
The MFR (190 ° C., 21.18 N load) of the component (B) used for the second layer of the laminate of the present invention is 0.1 g / 10 minutes or more and 5.0 g / 10 minutes or less, preferably 0. 5 g / 10 minutes or more, 3.0 g / 10 minutes or less, more preferably 0.7 g / 10 minutes or more, 2.0 g / 10 minutes or less, still more preferably 0.8 g / 10 minutes or more, 1. 5 g / 10 minutes or less. When the MFR of the component (B) is 0.1 g / 10 minutes or more, the resin pressure is low and the moldability is good, and when it is 5.0 g / 10 minutes or less, the bubbles are stable during inflation molding and the moldability is good. It is preferable because there is no possibility of exhibiting behavior inferior in heat resistance such as wrinkles on the sealant film after heat-pressurization sterilization treatment at more than 110 ° C. to less than 120 ° C.
Here, the MFR of the ethylene / α-olefin copolymer is measured in accordance with JIS K6922-2: 1997 Annex (190 ° C., 21.18 N load).

(B-ii) Density The density of the component (B) used in the second layer of the laminate of the present invention is 0.890 g / cm ³ or more, 0.925 g / cm ³ or less, preferably 0.900 g / cm ³ or more. , 0.923 g / cm ³ or less, more preferably 0.905 g / cm ³ or more, 0.920 g / cm ³ or less. When the density of the component (B) is 0.890 g / cm ³ or more, the sealant film is not likely to melt after the heat-pressurization sterilization treatment at more than 110 ° C. to less than 120 ° C., which is preferable. When it is 0.925 g / cm ³ or less, there is no possibility that the low temperature impact resistance is lowered, which is preferable.
Here, the density of the ethylene / α-olefin copolymer is measured at 23 ° C. in accordance with JIS K6922-2: 1997 Annex (in the case of low density polyethylene).

(B-iii) Content of α-olefin The content of α-olefin in the ethylene / α-olefin copolymer of the component (B) used in the second layer of the laminate of the present invention is 5% by weight or more, 40. It is preferably 7% by weight or more, more preferably 7% by weight or more, 35% by weight or less, still more preferably 9% by weight or more, and 30% by weight or less. When the content of α-olefin is 5% by weight or more, the impact strength and flexibility of the film are obtained, and when it is 40% by weight or less, the heat resistance is not impaired. Here, the content of α-olefin is a value measured by the 13C-NMR method under the following conditions.
Equipment: JEOL-GSX270 manufactured by JEOL
Concentration: 300 mg / 2 mL
Solvent: Orthodichlorobenzene

The ethylene / α-olefin copolymer of the component (B) may be one kind or a mixture of two or more kinds.

(B-iv) Ratio (Mw / Mn) of weight average molecular weight (Mw) to number average molecular weight (Mn)
The ratio (Mw / Mn) of the weight average molecular weight (Mw) of the component (B) to the number average molecular weight (Mn) is preferably 1.0 or more and 4.0 or less. It is preferably 1.5 or more and 3.5 or less, and more preferably 2.0 or more and 3.0 or less. When the ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is 1.0 or more, there is no possibility that the resin pressure will increase during molding, which is preferable. Further, when the ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is 4.0 or less, there is no possibility that the low temperature impact resistance is lowered, which is preferable. Examples of the method for adjusting Mw / Mn to a predetermined range include a method of selecting an appropriate metallocene catalyst.
The measurement of (Mw / Mn) is performed by gel permeation chromatography (GPC), and the measurement conditions are as follows.
Equipment: Waters GPC 150C type detector: MIRAN 1A infrared spectrophotometer (measurement wavelength 3.42 μm)
Column: Showa Denko AD806M / S 3 pieces (Column calibration is performed by Tosoh monodisperse polystyrene (0.5 mg / ml solution of each of A500, A2500, F1, F2, F4, F10, F20, F40, F288). Then, the logarithmic value of the elution volume and the molecular weight was approximated by a quadratic equation. The molecular weight of the sample was converted into polyethylene using the viscosity equations of polystyrene and polyethylene. Here, the coefficient of the viscosity equation of polystyrene was α = 0. 723, logK = -3.967, and polystyrene is α = 0.733, logK = -3.407.)
Measurement temperature: 140 ° C
Concentration: 20 mg / 10 mL
Injection amount: 0.2 ml
Solvent: Orthodichlorobenzene Flow rate: 1.0 ml / min.

(Bv) Maximum value of melting peak temperature The component (B) used for the second layer of the laminate of the present invention preferably has a maximum melting peak temperature of 115 ° C. or higher and lower than 130 ° C. in DSC measurement. ..
When the maximum value of the melting peak temperature is 115 ° C. or higher, the possibility of wrinkling is low after the heat-pressurization sterilization treatment of more than 110 ° C. and lower than 120 ° C. Further, when the maximum value of the melting peak temperature is less than 130 ° C., there is no possibility that the low temperature impact resistance is lowered, which is preferable. In the present invention, based on JIS K7121, using a DSC manufactured by Seiko Co., Ltd., a sample of 5.0 mg was taken, held at 200 ° C. for 5 minutes, and then crystallized to 30 ° C. at a temperature lowering rate of 10 ° C./min. Further, the melting peak temperature when melting at a heating rate of 10 ° C./min was confirmed.

(B-vi) Maximum value of elution peak temperature The maximum value of elution peak temperature was determined by TREF.
Measurement of elution curve obtained by TREF: The measurement of the elution curve by TREF in the present invention was performed as follows. A cross sorting device (manufactured by Mitsubishi Chemical Corporation, CFC / T150A) was used as a measuring device, and the measurement was performed according to the measurement method in the attached operation manual. This cross-separator has a temperature-increasing elution separation (TREF) mechanism that separates samples using the difference in melting temperature, and a size exclusion chromatography (SEC) that further separates the separated categories by molecular size. It is a device connected to online.
First, the sample to be measured (ethylene / α-olefin copolymer) is dissolved at 140 ° C. using a solvent (o-dichlorobenzene) so that the concentration becomes 4 mg / ml, and this is sampled in the measuring device. Infused into the loop. The following measurements were made automatically according to the set conditions.
The sample solution held in the sample loop is placed on a TREF column (a stainless steel column with an inner diameter of 4 mm and a length of 150 mm filled with glass beads, which is an inert carrier), which is separated by using the difference in melting temperature. 0.4 ml was injected. The sample was cooled from 140 ° C. to 0 ° C. at a rate of 1 ° C./min and coated on the Inactive Carrier. At this time, a polymer layer is formed on the surface of the inert carrier in the order of the high crystal component (easy to crystallize) to the low crystal component (difficult to crystallize). After holding the TREF column at 0 ° C. for another 30 minutes, 2 ml of the component dissolved at the temperature of 0 ° C. was transferred from the TREF column to the SEC column at a flow rate of 1 ml / min (Showa Denko KK, AD80M ・ S, 3 bottles). ) Was injected. While the SEC was fractionating by molecular size, the TREF column was heated to the next elution temperature (5 ° C.) and held at that temperature for about 30 minutes. Measurements of each elution category in SEC were performed at 39 minute intervals. The following temperatures were used as the elution temperature, and the temperature was raised stepwise.
Elution temperature (° C): 0,5,10,15,20,25,30,35,40,45,49,52,55,58,61,64,67,70,73,76,79,82, 85,88,91,94,97,100,102,120,140 ° C.
For the solutions separated by molecular size on the SEC column, the absorbance proportional to the concentration of the polymer was measured with the infrared spectrophotometer attached to the device (wavelength 3.42 μm, detected by expansion and contraction vibration of methylene), and each elution temperature classification. Chromatogram was obtained. Using the built-in data processing software, the baseline of the chromatogram of each elution temperature category obtained in the above measurement was drawn and arithmetically processed. The area of each chromatogram was integrated and the integrated elution curve was calculated. In addition, the differential elution curve was calculated by differentiating this integral elution curve with temperature. The drawing of the calculation result was output to the printer. In the drawing of the output differential elution curve, the horizontal axis is the elution temperature of 89.3 mm per 100 ° C, and the vertical axis is the differential amount (elution fraction: total integrated elution amount is 1.0, and the amount of change is 1 ° C. Was taken as the derivative amount) at 76.5 mm per 0.1.
Next, from this differential elution curve, the peak on the highest temperature side was set as the maximum value of the elution peak temperature.

The maximum value of the elution peak temperature is preferably 85 ° C. or higher and 100 ° C. or lower. It is more preferably 88 ° C. or higher and 95 ° C. or lower, and even more preferably 89 ° C. or higher and 94 ° C. or lower.
When the maximum value of the elution peak temperature is 85 ° C. or higher, the possibility of wrinkling is low after the heat-pressurization sterilization treatment of more than 110 ° C. and lower than 120 ° C. Further, when the maximum value of the elution peak temperature is 100 ° C. or lower, there is no possibility that the low temperature impact resistance is lowered, which is preferable.

(2) Component (D)
The high-pressure low-density polyethylene (component (D)) used for the second layer of the laminate of the present invention has the following characteristics (Di) to (D-ii).

(Di) Melt flow rate (MFR)
The MFR (190 ° C., 21.18 N load) of the component (D) used for the second layer of the laminate of the present invention is 0.1 g / 10 minutes or more and 5.0 g / 10 minutes or less, preferably 0. It is 5 g / 10 minutes or more and 4.0 g / 10 minutes or less, more preferably 0.7 g / 10 minutes or more and 3.0 g / 10 minutes or less. When the MFR of the component (D) is 0.1 g / 10 minutes or more, the resin pressure is low and the moldability is good, and when it is 5.0 g / 10 minutes or more, bubbles become unstable during inflation molding and the moldability is poor. It is preferable because there is no risk of becoming.
Here, the MFR of the component (D) is measured in accordance with JIS K6922-2: 1997 Annex (190 ° C., 21.18 N load).

(D-ii) Density The density of the component (D) used in the second layer of the laminate of the present invention is 0.915 g / cm ³ or more, 0.935 g / cm ³ or less, preferably 0.920 g / cm ³ or more. , 0.930 g / cm ³ or less, more preferably 0.923 g / cm ³ or more, 0.929 g / cm ³ or less. When the density of the component (D) is 0.915 g / cm ³ or more, there is no risk that the sealant film will melt after the heat-pressurization sterilization treatment of more than 110 ° C. to less than 120 ° C., and it is 0.935 g / cm ³ or less. This is preferable because there is no risk of deterioration in transparency.
Here, the density of the ethylene / α-olefin copolymer is measured at 23 ° C. in accordance with JIS K6922-2: 1997 Annex (in the case of low density polyethylene).

(3) Other Additive Components The ethylene-based resin layer II of the present invention may contain other additional optional components as long as the effects of the present invention are not significantly impaired. Such optional components include antioxidants (particularly phenol-based and phosphorus-based antioxidants are preferable), antiblocking agents, neutralizing agents, heat stabilizers, and crystals used in ordinary polyethylene-based resin materials. Examples thereof include nucleating agents, clearing agents, lubricants, colorants, dispersants, peroxides, fillers, fluorescent whitening agents and the like.
Further, in order to impart flexibility, a rubber compound such as an ethylene / α-olefin elastomer such as EBR and EPR and a styrene elastomer such as SEBS and HSBR can be blended.

(4) Blending Ratio of Component (B) and Component (D) The ethylene-based resin layer II of the present invention may contain the component (B), but preferably contains the component (D). The blending ratio of the component (B) and the component (D) is preferably 80% by weight or more and 99% by weight or less of the component (B), and 1% by weight or more and 20% by weight or less of the component (D), preferably. The component (A) is 85% by weight or more and 95% by weight or less, whereas the component (D) is 5% by weight or more and 15% by weight or less, and more preferably 85% by weight or more and 92% by weight of the component (B). , Component (D) is 8% by weight or more and 15% by weight or less.
When the component (B) is contained, there is no possibility that the flexibility, bag drop strength, and transparency after the heat-pressurization sterilization treatment of more than 110 ° C. to less than 120 ° C. are not deteriorated, which is preferable.

(6) Method for Preparing Ethylene Resin Layer II The component (B) and the component (D) contained in the ethylene resin layer II can be prepared by melt-kneading, if necessary.
More specifically, the component (B) and the component (D) may be dry-blended in advance, and the blend may be directly put into the hopper of the molding machine. Further, the blend may be melted and kneaded using an extruder, a lavender plastograph, a Banbury mixer, a kneader blender or the like, and pelletized by a commonly used method to produce a film or a sheet.

3. 3. Third layer The third layer of the laminate of the present invention may contain an ethylene / α-olefin copolymer (component (C)), but is preferably an ethylene / α-olefin copolymer (component (C)). )) It is composed of an ethylene resin layer III containing 70% by weight or more, 99% by weight or less, and 1% by weight or more and 30% by weight or less of high-pressure low-density polyethylene (component (D)).

(1) Ingredient (C)
The ethylene / α-olefin copolymer (component (C)) used for the third layer of the laminate of the present invention is a copolymer of ethylene and an α-olefin having 3 to 12 carbon atoms. The copolymer is an ethylene / α-olefin copolymer having the following characteristics (C-i) to (C-ii).
Hereinafter, the constituent monomers, the polymerization method, and the characteristics thereof will be sequentially described.

(C-i) Melt flow rate (MFR)
The MFR (190 ° C., 21.18 N load) of the component (C) used for the third layer of the laminate of the present invention is 0.1 g / 10 minutes or more and 5.0 g / 10 minutes or less, preferably 0. 1 g / 10 minutes or more, 4.5 g / 10 minutes or less, more preferably 0.5 g / 10 minutes or more, 3.0 g / 10 minutes or less, still more preferably 1.0 g / 10 minutes or more, 2. 5 g / 10 minutes or less. When the MFR of the component (C) is 0.1 g / 10 minutes or more, the resin pressure is low and the moldability is good, and when it is 5.0 g / 10 minutes or less, the bubbles are stable and the moldability is good during inflation molding. Further, it is preferable because there is no possibility of exhibiting behavior inferior in heat resistance such as wrinkling of the sealant film after the heat-pressurization sterilization treatment of more than 110 ° C. to less than 120 ° C.
Here, the MFR of the ethylene / α-olefin copolymer is measured in accordance with JIS K6922-2: 1997 Annex (190 ° C., 21.18 N load).

(C-ii) Density The density of the component (C) used in the third layer of the laminate of the present invention is 0.930 g / cm ³ or more, 0.950 g / cm ³ or less, preferably 0.933 g / cm ³ or more. , 0.945 g / cm ³ or less, more preferably 0.934 g / cm ³ or more, 0.940 g / cm ³ or less, still more preferably 0.935 g / cm ³ or more, 0.939 g / cm ³ or less. When the density of the component (C) is 0.930 g / cm ³ or more, there is no risk that the sealant film will melt after the heat-pressurization sterilization treatment of more than 110 ° C. to less than 120 ° C., and it is 0.950 g / cm ³ or less. This is preferable because there is no risk that the low-temperature impact resistance will decrease.
Here, the density of the ethylene / α-olefin copolymer is measured at 23 ° C. in accordance with JIS K6922-2: 1997 Annex.

It is preferable that the copolymer of ethylene of the component (C) and the α-olefin having 3 to 12 carbon atoms further has the following characteristics (C-iii) to (Cv).

(C-iii) Monomer composition The component (C) used for the third layer of the laminate of the present invention is a random copolymer of ethylene and α-olefin containing a structural unit derived from ethylene as a main component.
The α-olefin used as a comonomer is preferably an α-olefin having 3 to 12 carbon atoms. Specifically, propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-heptene, 4-methyl-pentene-1, 4-methyl-hexene-1, 4, 4-dimethylpentene- The first prize can be mentioned. Specific examples of such ethylene / α-olefin copolymers include ethylene / propylene copolymer, ethylene / 1-butene copolymer, ethylene / 1-hexene copolymer, ethylene / 1-octene copolymer, and ethylene. -Examples include 4-methyl-pentene-1 copolymer. Further, the α-olefin may be one kind or a combination of two or more kinds. When two kinds of α-olefins are combined into a terpolymer, examples thereof include ethylene / propylene / hexcentrpolymer, ethylene / butene / hexcentrpolymer, ethylene / propylene / octeneterpolymer, and ethylene / butene / octeneterpolymer. ..

(C-iv) Polymerization catalyst and polymerization method The component (C) used for the third layer of the laminate of the present invention can be produced by using a Ziegler catalyst, a vanadium catalyst, a metallocene catalyst, preferably a metallocene catalyst. Examples of the production method include a high-pressure ion polymerization method, a gas phase method, a solution method, and a slurry method.

(Cv)
The melt viscosity of the component (C) used for the third layer of the laminated body of the present invention preferably satisfies the following conditions.

(Cv-1) The melt viscosity (η ^* ₁ ) at a shear rate of 2.43 × 10s ^-1 , measured at 190 ° C., is 1.5 × 10 ⁴ poise or more and 7.0 × 10 ⁴ poise or less. (Cv-2) Melt viscosity (η ^* ₂ ) measured at 190 ° C. at a shear rate of 2.43 × 10 ² s ^-1 is 5.5 × 10 ³ poise or more, 3.0 × 10 ⁴ Below poise

The reason for focusing on the shear rate measured at 190 ° C. is to estimate the effect on the product during molding at that temperature. It is also effective for estimating the influence on the surface state of the film after the heat-pressurization sterilization treatment of more than 110 ° C. and lower than 120 ° C.

That is, the melt viscosity (η ^* ₁ ) at a shear rate of 2.43 × 10s ^-1 is 1.5 × 10 ⁴ poise or more, 7.0 × 10 ⁴ poise or less, and more preferably 2.0 × 10 ⁴ poise or more. It is 6.5 × 10 ⁴ poise or less, more preferably 2.5 × 10 ⁴ poise or more, and 6.0 × 10 ³ poise or less. When the melt viscosity (η ^* ₁ ) is not more than the upper limit, the extrusion load is low and the productivity is good. When it is at least the lower limit value, there is no risk of wrinkling of the film after the heat-pressurization sterilization treatment of more than 110 ° C. and less than 120 ° C.
The melt viscosity (η ^* ₁ ) can be adjusted by adjusting the melt flow rate (MFR) of the ethylene / α-olefin copolymer, the molecular weight distribution, and the like. As the value of the melt flow rate is increased, the melt viscosity (η ^* ₁ ) tends to decrease.
Further, the component (C) used in the present invention has a melt viscosity (η ^* ₂ ) of a shear rate of 2.43 × 10s ^-1 measured at 190 ° C. of 5.5 × 10 ³ poise or more and 3.0 ×. It is 10 ⁴ poise or less, more preferably 7.0 × 10 ³ poise or more, 2.5 × 10 ⁴ poise or less, still more preferably 8.0 × 10 ³ poise or more, 2.0 × 10 ⁴ poise or less. When the melt viscosity (η ^* ₂ ) is not more than the upper limit, the extrusion load is low and the productivity is good. When it is at least the lower limit value, there is no risk of wrinkling of the film after the heat-pressurization sterilization treatment of more than 110 ° C. and less than 120 ° C.
Here, the melt viscosities (η ^* ₁ ) and (η ^* ₂ ) are measured values obtained by using a capillary reometer having a capillary having a diameter of 1.0 mm and L / D = 10.
The reason why the two types of shear rates are provided is that the influence on the surface of the product during low-speed molding and high-speed molding is small, and the same product can be obtained in each molding speed region.

(2) Component (D)
The high-pressure method low-density polyethylene (component (D)) used for the third layer of the laminate of the present invention has the following characteristics (Di) to (D-ii).

(Di) Melt flow rate (MFR)
The MFR (190 ° C., 21.18 N load) of the component (D) used for the third layer of the laminate of the present invention is 0.1 g / 10 minutes or more and 5.0 g / 10 minutes or less, preferably 0. It is 5 g / 10 minutes or more and 4.0 g / 10 minutes or less, more preferably 0.7 g / 10 minutes or more and 3.0 g / 10 minutes or less. When the MFR of the component (D) is 0.1 g / 10 minutes or more, the resin pressure is low and the moldability is good, and when it is 5.0 g / 10 minutes or less, bubbles become unstable during inflation molding and the moldability is poor. It is preferable because there is no risk of becoming.
Here, the MFR of the ethylene / α-olefin copolymer is measured in accordance with JIS K6922-2: 1997 Annex (190 ° C., 21.18 N load).

(D-ii) Density The density of the component (D) used in the third layer of the laminate of the present invention is 0.915 g / cm ³ or more, 0.935 g / cm ³ or less, preferably 0.920 g / cm ³ or more. , 0.930 g / cm ³ or less, more preferably 0.923 g / cm ³ or more, 0.929 g / cm ³ or less. When the density of the component (D) is 0.915 g / cm ³ or more, there is no risk that the sealant film will melt after the heat-pressurization sterilization treatment of more than 110 ° C. to less than 120 ° C., and it is 0.935 g / cm ³ or less. This is preferable because there is no risk of deterioration in transparency.
Here, the density of the ethylene / α-olefin copolymer is measured at 23 ° C. in accordance with JIS K6922-2: 1997 Annex (in the case of low density polyethylene).

(3) Other Additive Components The ethylene-based resin layer III of the present invention may contain other additional optional components as long as the effects of the present invention are not significantly impaired. Such optional components include antioxidants (particularly phenol-based and phosphorus-based antioxidants are preferable), antiblocking agents, neutralizing agents, heat stabilizers, and crystals used in ordinary polyethylene-based resin materials. Examples thereof include nucleating agents, clearing agents, lubricants, colorants, dispersants, peroxides, fillers, fluorescent whitening agents and the like.
Further, in order to impart flexibility, a rubber compound such as an ethylene / α-olefin elastomer such as EBR and EPR and a styrene elastomer such as SEBS and HSBR can be blended.

(4) Blending Ratio of Component (C) and Component (D) The ethylene-based resin layer III of the present invention may contain the component (C), but preferably contains the component (D). The blending ratio of the component (C) and the component (D) is 70% by weight or more and 99% by weight or less of the component (C), and 1% by weight or more and 30% by weight or less of the component (D), preferably the component. (C) component (D) 5% by weight or more and 20% by weight or less with respect to 80% by weight or more and 95% by weight or less, and more preferably component (C) component (C) 80% by weight or more and 90% by weight or less. (D) 10% by weight or more and 20% by weight or less.
When the component (C) is contained, there is no possibility of exhibiting behavior inferior in heat resistance such as wrinkles on the sealant film after heat and pressure sterilization treatment at more than 110 ° C. to less than 120 ° C., which is preferable.

(5) Method for Preparing Ethylene Resin Layer III The component (C) and the component (D) contained in the ethylene resin layer III can be prepared by melt-kneading, if necessary.
More specifically, the component (C) and the component (D) may be dry-blended in advance, and the blend may be directly put into the hopper of the molding machine. Further, the blend may be melted and kneaded using an extruder, a lavender plastograph, a Banbury mixer, a kneader blender or the like, and pelletized by a commonly used method to produce a film or a sheet.

4. Laminated body The laminated body of the present invention may be one in which at least the first layer, the second layer and the third layer are laminated in this order, but in addition to the first layer, the second layer and the third layer. , Various layers generally used for such a laminated body can be appropriately provided as needed. Specifically, a tangent layer or a gas barrier layer such as EVOH or Ny can be provided between various layers.
Further, the thickness of the laminate of the present invention is preferably 30 to 100 μm. Within the above range, a film having excellent transparency can be stably formed, which is preferable.

The method for producing the laminate of the present invention is not particularly limited and can be carried out by a known method. It is preferably manufactured by the air-cooled inflation method.
Specifically, the above-mentioned resin materials for the first layer, the second layer, and the third layer are co-extruded using an extruder and a circular die, respectively, and air is introduced into the molten tube to expand and cool with the surrounding air. The film is formed by the air-cooled inflation molding method. The molding temperature is 160 to 280 ° C, preferably 170 to 230 ° C.
Further, the surface of the first layer opposite to the second layer has a treated surface subjected to corona treatment at the time of molding, and the surface of the third layer opposite to the second layer is a heat-sealed surface. It is preferable to have. Further, in this case, it is preferable to laminate a base material layer selected from PET, Ny, OPP, and AL on the treated surface side.

5. Applications The retort-packed sealant film made of the laminate of the present invention can be particularly suitably used for heat-pressurization sterilization treatment of more than 110 ° C. and lower than 120 ° C.

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited to these Examples. The evaluation methods and resins used in Examples and Comparative Examples are as follows.

1. 1. Evaluation method of resin physical properties (1) Melt flow rate (MFR): As described above, MFR was measured in accordance with JIS K6922-2: 1997 Annex (190 ° C., 21.18 N load).
(2) Density: As described above, the density of the component (A), the component (B), and the component (D) is 23 ° C. in accordance with JIS K6922-2: 1997 Annex (in the case of low density polyethylene). It was measured. The density of the component (C) was measured at 23 ° C. in accordance with JIS K6922-2: 1997 Annex.
(3) Α-olefin content: As described above, the α-olefin content was measured by the 13C-NMR method.
(4) Mw / Mn: As described above, it was measured by GPC.
(5) Melting peak: As described above, it was determined by DSC.

2. 2. Forming Method of Laminated Inflation film was molded and evaluated using the following inflation film film forming machine (molding apparatus) under the following molding conditions and with the formulations shown in Table 2.

(3 types, 3 layers, air-cooled inflation molding machine)
Equipment: Air-cooled inflation molding equipment (device name: DIREX, manufacturer: PLACO)
Extruder screw diameter: outer layer (third layer) / intermediate layer (second layer) / inner layer (third layer)
= 50 mmφ / 55 mmφ / 50 mmφ
Die diameter: 200 mmφ
Extrusion amount: 59 kg / hr
Die lip gap: 3mm
Pick-up speed: 17m / min Blow-up ratio: 2.0
Molding resin temperature: 180 ° C
Film thickness: 50 μm
Cooling ring: Two-stage air cooling ring with corona treatment (initial wetting tension: 45 dyn / cm or more)

A slip agent was added to all layers at 500 ppm, and an anti-blocking agent was added to the outer layer (third layer) and the inner layer (third layer) at 3040 ppm. Both were added using a masterbatch during molding.
The following master batches were used.
Slip agent masterbatch Kernel KMB05S manufactured by Japan Polyethylene Corporation
5% by weight masterbatch of slip agent Masterbatch of anti-blocking agent Kernel KMB16F manufactured by Japan Polyethylene Corporation
Anti-blocking agent 16% by weight masterbatch

3. 3. Manufacturing method of pouch A dry laminated film was produced by laminating a laminated body with biaxially stretched nylon (ONy) using a multi-coater (device model number: M500, manufacturer: HIRANO TECSEED).
Composition: ONy // PE film ONy: Made by Unitika: ONM Thickness: 15 μm
Adhesive: Toyo Morton TM-570 (polyester resin)
Using CAT-RT37 (polyisocyanate type) manufactured by Toyo Morton, the dry laminate film was folded in half in the vertical direction, three-way sealed so as to be 150 mm in length × 50 mm in width, and a pouch filled with 20 ml of tap water was prepared.
Of the three-way seals, the lower heat seal was performed under the following conditions.
Conditions: Upper bar temperature: 150 ° C, lower bar temperature: 60 ° C, gauge pressure: 0.2MPa, sealing time: 1 second Other parts are performed with an impulse sealer (device model number: P-300, manufacturer: Fuji Impulse). rice field.
To measure the heat seal strength (using the lower seal part) and haze after heat-pressurization sterilization, drain water from the pouch and adjust the condition in a 23 ° C x 50% RH constant temperature and humidity chamber for 24 hours. A film was used.

4. Evaluation method of laminated body (1) Film impact: Measurement was performed with a film impact tester with reference to JIS P8134. A 1-inch ball (made of aluminum) was used as the impact ball. In this development, the target value of impact resistance was set to 20 J / 10 mm or more in an environment of 23 ° C. × 50% RH. If this condition is satisfied, sufficient impact resistance can be obtained even during low-temperature distribution based on conventional knowledge.

5. Evaluation method of pouch The pouch was sterilized by heating under pressure at 115 ° C. using a high-temperature high-pressure cooking sterilization tester (device model number: YRF-40 / 50EZ, manufacturer: Chiyoda Electric, method: hot water shower type).
For these pouches, the appearance, the presence or absence of fusion between the seal layers, the dimensional stability, the heat seal strength, and the haze were evaluated. For the measurement of the heat seal strength and haze after the heat-pressurization sterilization treatment, water was drained from the pouch and a film after adjusting the state for 24 hours in a 23 ° C. × 50% RH constant temperature and humidity chamber was used.

(1) Appearance “○” was given when no abnormalities (wrinkles, broken bags, etc.) were found, and “×” was given when they were found.

(2) Fusion The case where fusion was not seen was marked with "○", and the case where fusion was seen was marked with "x".

(3) Dimensional stability The vertical lengths of the dry laminated films were compared before and after the pouch treatment. If the change in length in the vertical direction was within ± 10%, it was evaluated as “◯”, and if it exceeded ± 10%, it was evaluated as “x”.

(4) Heat seal strength Measurement was performed with a tensile tester with reference to JIS K1713.

(5) Measured based on Haze JIS K7136.

6. Resin used (1) Component (A): Ethylene / α-olefin copolymer As the component (A), the following three types of resins were used. It is shown in Table 1.
A-1: Harmorex NF366A manufactured by Japan Polyethylene Corporation (MFR 1.5 g / 10 min, density 0.919 g / cm ³ )
A-2: Harmorex NC596A manufactured by Japan Polyethylene Corporation (MFR 4.0 g / 10 min, density 0.931 g / cm ³ )
A-3: Harmorex NF395A manufactured by Japan Polyethylene Corporation (MFR 1.5 g / 10 min, density 0.935 g / cm ³ )

(2) Component (B): Ethylene / α-olefin copolymer As the component (B), the following resin produced with a metallocene catalyst was used. It is shown in Table 1.
B-1: Harmorex NF324A manufactured by Japan Polyethylene Corporation (MFR 1.0 g / 10 min, density 0.906 g / cm ³ )
B-2: Harmorex NF366A manufactured by Japan Polyethylene Corporation (MFR 1.5 g / 10 min, density 0.919 g / cm ³ )
B-3: Kernel KF270 manufactured by Japan Polyethylene Corporation (MFR 2.0 g / 10 min, density 0.907 g / cm ³ )
B-4: Harmorex NC596A manufactured by Japan Polyethylene Corporation (MFR 4.0 g / 10 min, density 0.931 g / cm ³ )
B-5: Harmorex NF395A manufactured by Japan Polyethylene Corporation (MFR 1.5 g / 10 min, density 0.935 g / cm ³ )

(3) Component (C): Ethylene / α-olefin copolymer As the component (C), the following three types of resins were used. It is shown in Table 1.
C-1: Harmorex NF366A manufactured by Japan Polyethylene Corporation (MFR 1.5 g / 10 min, density 0.919 g / cm ³ )
C-2: Harmorex NC596A manufactured by Japan Polyethylene Corporation (MFR 4.0 g / 10 min, density 0.931 g / cm ³ )
C-3: Harmorex NF395A manufactured by Japan Polyethylene Corporation (MFR 1.5 g / 10 min, density 0.935 g / cm ³ )

(4) Component (D): As the high-pressure method low-density polyethylene component (D), the following commercially available resin was used. It is shown in Table 1.
D-1: Novatec LD LF441B manufactured by Japan Polyethylene Corporation (MFR 2.0 g / 10 min, density 0.924 g / cm ³ )

[Example 1]
An ethylene resin layer I containing (A-1) 93% by weight and (D-1) 7% by weight was used in the first layer, and (B-2) 93% by weight and (D) were used in the second layer. -1) An ethylene resin layer II containing 7% by weight was used, and an ethylene resin layer III composed of (C-3) 90% by weight and (D-1) 10% by weight was used as the third layer. ..
The resin material of each of these layers was set in the above-mentioned three-kind three-layer air-cooled inflation molding machine manufactured by PLACO Co., Ltd., and air-cooled inflation molding was performed under the above conditions to obtain a thickness of 50 μm (layer ratio: first layer / second layer / first layer). A laminated body of 3 layers = 1/1/1) was obtained and evaluated. Furthermore, a pouch was prepared and evaluated. The results are shown in Table 2.

[Example 2]
A laminated body was obtained and evaluated in the same manner as in Example 2 except that the layer ratio was set to 1st layer / 2nd layer / 3rd layer = 1/3/1. The results are shown in Table 2.

[Example 3]
A laminate was obtained and evaluated in the same manner as in Example 1 except that the ethylene resin layer II having (B-1) 90% by weight and (D-1) 10% by weight was used for the second layer. rice field. The results are shown in Table 2.

[Comparative Example 1]
A laminate was obtained in the same manner as in Example 1 and evaluated, except that the ethylene resin layer III composed of (C-3) 93% by weight and (D-1) 7% by weight was used for the third layer. gone. The results are shown in Table 2.
In this product, fusion occurred after heat and pressure sterilization at 115 ° C.

[Comparative Example 2]
An ethylene resin layer I containing 90% by weight of (A-2) and 10% by weight of (D-1) was used in the first layer, and 90% by weight of (B-4) and (D-) were used in the second layer. 1) Except for using an ethylene resin layer II containing 10% by weight and using an ethylene resin layer III containing (C-2) 90% by weight and (D-1) 10% by weight in the third layer. A laminate was obtained in the same manner as in Example 1 and evaluated. The results are shown in Table 2.
This product had an impact strength value of less than 20 J / mm before the 115 ° C. heat and pressure sterilization treatment.

[Comparative Example 3]
An ethylene resin layer I containing (A-3) 90% by weight and (D-1) 10% by weight was used in the first layer, and (B-5) 90% by weight and (D-) were used in the second layer. 1) Except for using an ethylene resin layer II containing 10% by weight and using an ethylene resin layer III containing (C-3) 90% by weight and (D-1) 10% by weight as the third layer. , A laminated body was obtained in the same manner as in Example 1 and evaluated. The results are shown in Table 2.
This product had an impact strength value of less than 20 J / mm before the 115 ° C. heat and pressure sterilization treatment.

[Comparative Example 4]
A laminate was obtained in the same manner as in Example 1 and evaluated, except that the ethylene resin layer II containing (B-3) 90% by weight and (D-1) 10% by weight was used for the second layer. gone. The results are shown in Table 2.
This product wrinkled after heat pressure sterilization at 115 ° C.

Since the sealant film for retort foods made of the laminate of the present invention has an excellent balance between low-temperature impact resistance and high-temperature heat resistance, it can be suitably used not only for storage at room temperature but also for low-temperature distribution (frozen to chilled).

Claims (7)

A laminate in which at least the first layer, the second layer, and the third layer are laminated in this order, the first layer containing the component (A), the second layer containing the component (B), and the first layer. A retort-packed sealant film having a film thickness of 30 μm to 100 μm, comprising a laminate having three layers containing the component (C).
Component (A): Copolymer of ethylene having the following characteristics (A-i) to (A-ii) and α-olefin having 3 to 12 carbon atoms (A-i) Melt flow rate (190 ° C., 21) .18N load) is 0.1 g / 10 minutes or more, 5.0 g / 10 minutes or less (A-ii) Density is 0.915 g / cm ³ or more, 0.925 g / cm ³ or less Component (B): The following (B) Copolymer of ethylene and α-olefin having 3 to 12 carbon atoms produced by using a metallocene catalyst having the characteristics of Bi) to (Bv) (Bi) Melt flow rate (190 ° C., 21.18N load) is 0.1g / 10 minutes or more, 5.0g / 10 minutes or less (B-ii) Density is 0.890g / cm ³ or more, 0.925g / cm ³ or less (B-iii) α- Olefin content is 5% by weight or more and 40% by weight or less (B-iv) The ratio (Mw / Mn) of the weight average molecular weight (Mw) and the number average molecular weight (Mn) determined by gel permeation chromatography (GPC). ) Is 1.0 or more and 4.0 or less (Bv) The maximum value of the melting peak temperature is 115 ° C or more and less than 130 ° C. Copolymer of ethylene and α-olefin having 3 to 12 carbon atoms (Ci) Melt flow rate (190 ° C, 21.18N load) is 0.1 g / 10 minutes or more, 5.0 g / 10 minutes or less (C-ii) Density is 0.930 g / cm ³ or more, 0.950 g / cm ³ or less The first layer is composed of an ethylene resin layer I containing 70% by weight or more and 99% by weight or less of the component (A) and 1% by weight or more and 30% by weight or less of the following component (D), and the second layer is a component. (B) is composed of an ethylene resin layer II containing 80% by weight or more and 99% by weight or less, and the following component (D) 1% by weight or more and 20% by weight or less, and the third layer is 70% by weight of the component (C). The retort food sealant film according to claim 1, which comprises an ethylene resin layer III containing% or more, 99% by weight or less, and the following component (D) of 1% by weight or more and 30% by weight or less.
Component (D): High-pressure low-density polyethylene (D-i) melt flow rate (190 ° C., 21.18 N load) having the following characteristics (D-i) to (D-ii) is 0.1 g / 10 minutes. 5.0 g / 10 minutes or less (D-ii) Density is 0.915 g / cm ³ or more, 0.935 g / cm ³ or less The first layer is composed of an ethylene resin layer I containing 80% by weight or more of the component (A) and 95% by weight or less, and 5% by weight or more and 20% by weight or less of the component (D), and the second layer is a component. (B) is composed of an ethylene resin layer II containing 85% by weight or more and 95% by weight or less, and component (D) 5% by weight or more and 15% by weight or less, and the third layer is 80% by weight of component (C). The retort food sealant film according to claim 1 or 2, which comprises the ethylene resin layer III containing 95% by weight or less, and 5% by weight or more and 20% by weight or less of the component (D). .. The retort according to any one of claims 1 to 3, wherein the component (B) is an α-olefin copolymer of ethylene having the following characteristics (B-vi) and 3 to 12 carbon atoms. Food sealant film.
(B-vi) In the elution curve, the maximum value of the elution peak temperature is 85 ° C or higher and 100 ° C or lower. The surface of the first layer opposite to the second layer was treated with a corona treatment during molding, and the surface of the third layer opposite to the second layer was used as a heat seal surface. The sealant film for retort food according to any one of claims 1 to 4. A retort food sealant film in which a base material layer selected from PET, Ny, OPP, and AL is laminated on the treated surface side of the retort food sealant film according to claim 5. A pouch using the retort food sealant film according to claim 5.