JP6425870B2 - Sealant, laminate using the same and packaging bag for microwave oven - Google Patents

Description

  The present invention relates to a sealant, a laminate using the same, and a packaging bag for a microwave oven, and more particularly, by using the packaging bag for a microwave oven, it is possible to suppress the deterioration of the flavor of the contents and transport The present invention relates to a sealant which is easily peeled off by internal pressure when heated in a microwave oven without peeling due to pressure or shock applied at the time or storage, a laminate using the same, and a packaging bag for a microwave oven.

  In recent years, with the spread and development of microwave ovens, and also from the request of simplification of cooking, cooked processed food is packaged in a plastic packaging bag and the like, sealed, and distributed in a form having shelf life. ing. Also, conventionally, a self-supporting packaging bag (so-called standing pouch) has been folded into two body members whose side portions are sealed and a peripheral edge of which is sealed at the lower end portions of the two body members. And a bottom member. Furthermore, the bottom member is formed at a point about 25 mm inward from the end of the folded portion, and the front and rear body members are thermally welded through the semicircular punch hole.

  The above-mentioned self-supporting packaging bag has a flat structure before filling the contents, but after filling the contents inside, the folded bottom member spreads due to the weight of the contents and is formed into a substantially conical shape to be self-supporting It is Such a self-supporting packaging bag can be displayed in a stand-alone state at the shop front, so the width of the display space can be minimized and the appearance for the customer is also good. Furthermore, the packaging bag is self-supporting in a microwave oven It can be heated and cooked, and after cooking, it is transferred to a container and used.

  As a technique relating to the improvement of such a self-supporting packaging bag, for example, Patent Document 1 discloses that even if the packaging bag is heated in a microwave while being in a self-standing state, the self-standing packaging is not rolled over while rotating on a tray. There has been proposed a packaging bag for a microwave oven which is excellent in stability, filling aptitude of contents, and display effect at a store. In addition to the above advantages, such a packaging bag for microwave ovens is capable of automatically peeling off the sealant by the internal pressure in the packaging bag when heated in the microwave oven and reducing the internal pressure in the packaging bag. Can be safely cooked without spillage, withstand boiling and retort sterilization, and can be manufactured efficiently.

Unexamined-Japanese-Patent No. 2006-327590

  As described above, conventionally, the packaging bag for the microwave oven has been studied from the viewpoints of self-standing stability, filling aptitude of contents, safety during handling, manufacturing efficiency, and the like. However, in recent years, there has been an increasing demand for retort foods such as long-term preservation without impairing the flavor of the packaged contents. In order to obtain a microwave packaging bag satisfying such a demand, development of a new technology is necessary.

  Therefore, it is an object of the present invention to suppress deterioration of the flavor of the contents by using it for a packaging bag for a microwave oven, and to prevent the peeling off due to pressure or impact applied during transportation or storage. It is an object of the present invention to provide a sealant which can be easily peeled off by internal pressure when heated in a microwave oven, a laminate using the same, and a packaging bag for a microwave oven.

  As a result of intensive studies to solve the above problems, the present inventors set the sealant to a predetermined configuration, so that sufficient seal strength is obtained at normal temperature, and the seal strength is reduced at the time of microwave heating, It has been found that it is possible to prevent the deterioration of the flavor due to the oxidative deterioration of the contents by preventing the entry of oxygen into the inside of the packaging bag while maintaining the property of the sealant peeling off quickly, and to complete the present invention. It reached.

That is, the sealant of the present invention is a sealant having a polyolefin resin layer / adhesive resin layer / non-ferrous oxygen absorbing resin layer / adhesive resin layer / food contact layer in this order,
When the sealants are thermally bonded with the food contact layer inside, the seal strength at 23 ° C. is 23 to 100 N / 15 mm, and the seal strength at 90 ° C. is 5 to 25 N / 15 mm,
The nonferrous oxygen-absorbing resin layer is composed of a resin composition containing an oxygen absorbent consisting of a conjugated diene polymer cyclized and a base resin, and an oxygen absorbent consisting of the conjugated diene polymer cyclized and the base When the total mass with the resin is 100% by mass, it contains more than 5% by mass and 30% by mass or less of the oxygen absorbent composed of the above-mentioned conjugated diene polymer cyclized product,
The food contact layer comprises a propylene-ethylene block copolymer (A), a propylene-ethylene block copolymer (B), and an ethylene-butene-1 copolymer containing 15% by mass or more of butene-1. A resin composition comprising: propylene block (I) 65, wherein the propylene-ethylene block copolymer (A) is a propylene homopolymer or a propylene-ethylene copolymer having an ethylene content of 2% by mass or less And 85% by mass, and 15 to 35% by mass of ethylene-propylene copolymer block (II) having an ethylene content of 20 to 95% by mass, and the propylene-ethylene block copolymer (B) has a propylene single weight Propylene block (III) 85 to 85 composed of a combined or propylene-ethylene copolymer having an ethylene content of 2% by mass or less And 5 wt%, an ethylene content of 20 to 95 wt% ethylene - consists propylene copolymer block (IV) a resin composition containing 5 to 15 wt%,
The content of the propylene-ethylene block copolymer (A) is 25 to 50% by mass, and the content of the propylene-ethylene block copolymer (B) is 25 to 70 for the resin composition constituting the food contact layer. The content of the ethylene-butene-1 copolymer is in the range of 5 to 30% by mass.

  The sealant of the present invention can be suitably produced by coextrusion.

  The laminate of the present invention is characterized by using the above-mentioned sealant of the present invention.

  Furthermore, the packaging bag for microwave ovens of this invention is characterized by using the laminated body of the said invention.

  ADVANTAGE OF THE INVENTION According to this invention, deterioration in the flavor of the content can be suppressed by using for the packaging bag for microwave ovens, and without peeling by the pressure or impact added at the time of transportation or storage, with a microwave oven The sealant which exfoliates easily by internal pressure at the time of heating, the layered product using it, and the packaging bag for microwave ovens can be obtained.

FIG. 1 is a cross-sectional view of one preferred embodiment of the sealant of the present invention. It is sectional drawing of one preferable embodiment of the laminated body of this invention. BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows one preferable embodiment of the packaging bag for microwave ovens of this invention, (a) A laminated body which comprises a packaging bag, (b) The top view of a packaging bag, (c) It is a perspective view of a packaging bag (D) It is sectional drawing of a packaging bag. It is a figure which shows the example of the shape of the square-C-shaped seal in the packaging bag for microwave ovens of this invention. It is a figure which shows the example of the shape of the notch or notch formed in the unsealed part enclosed by square-C-shaped seal. It is sectional drawing of the XX line of FIG. It is explanatory drawing which shows each dimension of the packaging bag for microwave ovens of this invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.
The sealant of the present invention has at least an oxygen-absorbing resin layer and a food contact layer. FIG. 1 is a cross-sectional view of one preferred embodiment of the sealant 10 of the present invention, and in the illustrated example, a polyolefin resin layer 1, an adhesive resin layer 2a, an oxygen absorbing resin layer 3, and an adhesive resin layer 2b. , And the food contact layer 4 are laminated in order.

  In the present invention, it is important to provide the sealant 10 with the non-ferrous oxygen-absorbing resin layer 3. The oxygen barrier property of the sealant 10 is improved by providing the sealant 10 with the non-ferrous oxygen-absorbing resin layer 3. Therefore, when the sealant 10 of the present invention is used as a sealant of a packaging bag for a microwave oven, deterioration of the flavor due to oxidation of the contents is prevented, and the contents can be stored for a long time. In the present invention, when the sealants 10 are thermally bonded with the food contact layer 4 inside, the seal strength at 23 ° C. is 23 to 100 N / 15 mm, and the seal strength at 90 ° C. is 5 to 25 N It is also important that it is / 15 mm. When the food contact layers 4 of the sealant 10 are thermally bonded to each other, if the seal strength at 23 ° C. is less than 23 N / 15 mm, the seal portion may be peeled off by pressure or shock applied during transportation or storage. The upper limit of the seal strength is not particularly limited, but is preferably 23 to 100 N / 15 mm. Moreover, the seal strength at 90 ° C. is 5 to 25 N / 15 mm. If the seal strength at 90 ° C. exceeds 25 N / 15 mm, there is a possibility that the automatic opening may not be achieved quickly and reliably, and the bag may be broken, which is not preferable. Preferably, it is 10 to 15 N / 15 mm. Hereafter, each layer which comprises the sealant 10 of this invention is demonstrated in detail.

First, the food contact layer 4 of the sealant 10 of the present invention will be described.
The resin constituting the food contact layer 4 of the sealant 10 of the present invention is generally used as a packaging material for food which is heated or cooked in a microwave oven, and the sealant 10 is thermally bonded with the food contact layer 4 inside. There is no particular limitation as long as the resin has a seal strength of 23 to 100 N / 15 mm at 23 ° C. and 5 to 25 N / 15 mm at 90 ° C., for example, using a polyolefin resin Can.

  Examples of the polyolefin resin include low density polyethylene, linear low density polyethylene, medium density polyethylene, high density polyethylene, polypropylene, propylene-ethylene copolymer, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer Examples thereof include resins such as united, ethylene-methacrylic acid copolymer, ethylene-methyl acrylate copolymer, ethylene-ethyl acrylate copolymer, ethylene-methyl methacrylate copolymer or ionomer.

  In the present invention, an ethylene-butene-1 containing at least 15 mass% of a propylene-ethylene block copolymer (A), a propylene-ethylene block copolymer (B), and butene-1 among polyolefin resins. A resin composition comprising a copolymer, wherein the propylene-ethylene block copolymer (A) comprises a propylene homopolymer or a propylene-ethylene copolymer having an ethylene content of 2% by mass or less. (I) contains 65 to 85% by mass, and 15 to 35% by mass of ethylene-propylene copolymer block (II) having an ethylene content of 20 to 95% by mass, and a propylene-ethylene block copolymer (B) Propylene homopolymer comprising propylene homopolymer or propylene-ethylene copolymer having an ethylene content of 2% by mass or less Preferably using a resin composition containing 85 to 95% by mass of Cu (III) and 5 to 15% by mass of ethylene-propylene copolymer block (IV) having an ethylene content of 20 to 95% by mass it can. By applying such a resin composition to the food contact layer 4, the above-mentioned physical properties can be easily satisfied.

  In the polymerization step of the propylene-ethylene block copolymer (A) and the propylene-ethylene block copolymer (B) constituting the above resin composition, a homopolymer of propylene or a propylene having an ethylene content of 2% by mass or less is used. It consists of the 1st polymerization process which forms the propylene block which consists of ethylene copolymers, and the 2nd polymerization process which polymerizes the ethylene-propylene copolymer block which has ethylene content in the range of 20-95 mass%.

  First, as a first polymerization step, a catalyst is added to a raw material propylene or a mixture of propylene and ethylene as a raw material, and a propylene block consisting of a propylene homopolymer or a propylene-ethylene copolymer having an ethylene content of 2% by mass or less is It polymerizes so that it may become the quantity equivalent to 65 to 95 mass% of the total amount of polymers finally obtained.

  Next, a second polymerization step is carried out subsequently to the first polymerization step, and a mixture of propylene and ethylene is further introduced into the propylene block produced in the first polymerization step, and the ethylene content is 20 to 95 mass%. The ethylene-propylene block copolymer is polymerized to an amount corresponding to 5 to 35% by mass of the total polymer amount.

  The propylene-ethylene block copolymers (A) and (B) may be polymerized either batchwise or continuously. In polymerization, a method of polymerization in an inert hydrocarbon solvent such as hexane or heptane, a method of using propylene as a solvent substantially without using an inert solvent, a gaseous state substantially without using a liquid solvent A method of carrying out the polymerization in the monomers of the above, or a method combining these can be used. The first polymerization step and the second polymerization step may use the same polymerization tank, or may use separate polymerization tanks.

  Although propylene and ethylene are used as the raw materials of the propylene-ethylene block copolymers (A) and (B), other olefins, for example, as long as they do not impair the intended effect of the present invention as required Butene-1, 4-methyl-pentene-1 etc. may be added. The catalysts used in the polymerization of the propylene-ethylene block copolymers (A) and (B) include magnesium, halogen, titanium, a magnesium-supported solid catalyst containing an electron donor as an essential component, trichloride A catalyst comprising a solid catalyst component mainly composed of titanium and an organoaluminum, a metallocene catalyst, or the like can be used.

  Next, the roles of the propylene-ethylene block copolymers (A) and (B) and the ethylene-butene-1 copolymer will be described. The propylene-ethylene block copolymer (A) has a high content of a polymerized rubber block (ethylene-propylene copolymer block (II) containing 20 to 95% by mass of ethylene), and a propylene-ethylene block copolymer (A) Since the melt flow rate (MFR (A)) is low, the cold shock resistance is also improved in addition to the heat seal strength, and the storage and distribution in cold regions where the temperature is 0 ° C. or less are also excellent. The propylene-ethylene block copolymer (B) has a low content of a polymerized rubber block (ethylene-propylene copolymer block (IV) containing 20 to 95% by mass of ethylene), and a propylene-ethylene block copolymer (B) Since the melt flow rate (MFR (B)) of the above is high, the adornment skin aptitude which suppresses the coconut skin phenomenon which produces fine unevenness in an outer layer by heat sterilization improves. The ethylene-butene-1 copolymer contributes to the improvement of satin skin suitability and the improvement of cold shock resistance.

  However, in the resin composition containing these components as an essential main component, an increase in the content of the propylene-ethylene block copolymer (A) may lead to a decrease in suitability for coconut skin, a propylene-ethylene block copolymer (B An increase in content may lead to a decrease in heat seal strength after retort sterilization and a decrease in cold impact resistance, and an increase in ethylene-butene-1 copolymer content may lead to a decrease in heat seal strength after retort sterilization There is. Therefore, in the present invention, the content of the propylene-ethylene block copolymer (A) is 25 to 50% by mass, the content of the propylene-ethylene block copolymer (B) is 25 to 70% by mass, and ethylene-butene-1 The content of the copolymer is preferably in the range of 5 to 30% by mass. Outside this range, a heat-sealable film may be formed which is inferior in any of heat-sealing aptitude, satin skin aptitude and cold impact resistance.

  Moreover, in the present invention, MFR (A) and MFR (B) are respectively 0.5 to 1.5 g / 10 min (230 ° C., load 2.16 kg) and 1.0 to 4.0 g / 10 min. It is preferable to be in the range of (230 ° C., load 2.16 kg). The heat sealability and the cold impact resistance are excellent by using the propylene-ethylene block copolymer (A) having such aptitude as the first component and the propylene-ethylene block copolymer (B) as the second component, and It is possible to make a retort pouch free from the occurrence of the coconut skin phenomenon.

  The compositional ratio and melt of propylene-ethylene block copolymer (A), propylene-ethylene block copolymer (B) and ethylene-butene-1 copolymer involved in heat seal strength, cold impact resistance, and satin skin suitability The flow rate will be described. By setting MFR (A) in the range of 0.5 to 1.5 g / 10 min, heat seal strength and cold impact resistance can be improved. When the MFR (A) is less than 0.5 g / 10 min, the high-speed film formation suitability is extremely reduced. When the MFR (A) exceeds 1.5 g / 10 min, the effect of improving the heat seal strength and the cold impact resistance may be insufficient.

  In addition, the ratio of MFR (A) to the melt flow rate of propylene block (I) (MFR (I)), that is, MFR (A) / MFR (I) is within the range of 0.01 to 0.3. By doing this, the heat seal strength and the cold shock resistance can be further improved. The MFR (I) can be measured at the end of the first polymerization step described above. If the value of MFR (A) / MFR (I) is less than 0.01, it is difficult to obtain a film with a good appearance. On the other hand, when the value of MFR (A) / MFR (I) exceeds 0.3, cold impact resistance and heat seal strength may be insufficient, which is not preferable.

  Furthermore, the content of the ethylene-propylene copolymer (II) formed in the second polymerization step of the propylene-ethylene block copolymer (A) is preferably in the range of 15 to 35% by mass. When the content of the ethylene-propylene copolymer (II) is less than 15% by mass, the effect of improving the cold impact resistance is small, and when it exceeds 35% by mass, the powder of the produced propylene-ethylene block copolymer becomes sticky However, it is not preferable because it is agglomerated or stuck to the inner wall of the polymerization tank, which lowers the productivity.

  Further, in the present invention, by setting the MFR (B) in the range of 1.0 to 4.0 g / 10 min, it is possible to improve the coconut skin suitability. If the MFR (B) is less than 1.0 g / 10 min, the high-speed film formation suitability is poor. When the MFR (B) exceeds 4.0 g / 10 min, the improvement effect on the apricot skin suitability becomes insufficient.

  Furthermore, the ratio of MFR (B) to the melt flow rate of propylene block (III) (MFR (III)), that is, MFR (B) / MFR (III) is in the range of 0.5 to 0.95 By doing this, it is possible to further improve the yuzu skin suitability. The MFR (III) can be measured when the first polymerization step is completed. When the value of MFR (B) / MFR (III) is less than 0.5 or exceeds 0.95, the effect of improving the skin of coconut skin is insufficient, which is not preferable.

  Furthermore, the content of the ethylene-propylene copolymer (IV) formed in the second polymerization step of the propylene-ethylene block copolymer (B) is preferably in the range of 5 to 15% by mass. If the content of the ethylene-propylene copolymer (IV) is less than 5% by mass, the effect of improving the suitability for coconut skin becomes insufficient, and if it exceeds 15% by mass, the heat seal strength may be insufficient.

Next, the oxygen-absorbing resin layer 3 of the sealant 10 of the present invention will be described.
The oxygen-absorbing resin layer 3 is made of a resin composition containing a non-ferrous oxygen absorber and a base resin, but in the present invention, a conjugated diene polymer cyclized is used as the oxygen absorber. Conventionally, iron-based oxygen absorbents have been widely used as oxygen absorbents, but when using iron-based oxygen absorbents, the transparency of the packaging bag is impaired, and when heated with a microwave oven, There is also a risk of ignition. Therefore, when using an iron-based oxygen absorbent as the oxygen absorbent, it is necessary to suppress the addition amount to such an extent that there is no risk of ignition and that the transparency of the packaging bag is not impaired. On the other hand, if it is a conjugated diene polymer cyclization thing, there is no such a restriction | limiting and it can add more than the iron-type oxygen absorbent. Therefore, in order to prevent the oxidative deterioration of the contents filled in the packaging bag over a long period of time, it is necessary to use a conjugated diene polymer cyclized product.

  An oxygen absorbent consisting of a conjugated diene polymer cyclized product can be obtained by subjecting a conjugated diene polymer to a cyclization reaction in the presence of an acid catalyst. As the conjugated diene polymer, homopolymers and copolymers of conjugated diene monomers and copolymers of conjugated diene monomers and monomers copolymerizable therewith can be used. The conjugated diene monomer is not particularly limited. For example, 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 2-phenyl-1,3-butadiene, 1,3-pentadiene And 2-methyl-1,3-pentadiene, 1,3-hexadiene, 4,5-diethyl-1,3-octadiene, 3-butyl-1,3-octadiene and the like. One of these monomers may be used alone, or two or more of these monomers may be used in combination.

  As another monomer which can be copolymerized with a conjugated diene monomer, for example, styrene, o-methylstyrene, p-methylstyrene, m-methylstyrene, 2,4-dimethylstyrene, ethylstyrene, p-tert Aroma such as-butylstyrene, α-methylstyrene, α-methyl-p-methylstyrene, o-chlorostyrene, m-chlorostyrene, p-chlorostyrene, p-bromostyrene, 2,4-dibromostyrene, vinyl naphthalene and the like Group vinyl monomers; linear olefin monomers such as ethylene, propylene and 1-butene; cyclic olefin monomers such as cyclopentene and 2-norbornene; 1,5-hexadiene, 1,6-heptadiene, 1,7 Non-conjugated diene monomers such as octadiene, dicyclopentadiene, 5-ethylidene-2-norbornene; (meth) a (Meth) acrylic acid esters such as methyl acrylate, ethyl (meth) acrylate; other (meth) acrylic acid derivatives such as (meth) acrylonitrile and (meth) acrylamide; and the like. One of these monomers may be used alone, or two or more of these monomers may be used in combination.

  Specific examples of homopolymers and copolymers of conjugated diene monomers include natural rubber (NR), polyisoprene rubber (IR), polybutadiene rubber (BR), butadiene-isoprene copolymer rubber (BIR), etc. It can be mentioned. Among them, polyisoprene rubber and polybutadiene rubber are preferable, and polyisoprene rubber is more preferable. These conjugated diene polymers may be used alone or in combination of two or more.

  As a specific example of the copolymer of a conjugated diene monomer and a monomer copolymerizable therewith, for example, styrene-isoprene rubber (SIR), styrene-butadiene rubber (SBR), isoprene-isobutylene copolymer Rubber (IIR), ethylene-propylene-diene copolymer rubber (EPDM), etc. can be mentioned. Among them, preferred is a block copolymer comprising an aromatic vinyl polymer block having a weight average molecular weight of 1,000 to 500,000 and at least one conjugated diene polymer block. These conjugated diene polymers may be used alone or in combination of two or more.

  The content of the conjugated diene monomer unit in the conjugated diene polymer may be suitably selected within the range that does not impair the effects of the present invention, but usually 40 mol% or more, preferably 60 mol% or more, more preferably 75 It is mol% or more. If the content of the conjugated diene monomer unit is too low, it may be difficult to obtain an appropriate range of unsaturated bond reduction rate. The polymerization method of the conjugated diene polymer may be a conventional method, for example, solution polymerization or an appropriate catalyst such as a Ziegler type polymerization catalyst containing titanium etc. as a catalyst component, an alkyllithium polymerization catalyst or a radical polymerization catalyst It may be polymerized by emulsion polymerization.

  The conjugated diene polymer cyclized product used in the present invention is obtained by subjecting the conjugated diene polymer to a cyclization reaction in the presence of an acid catalyst, thereby cyclizing the conjugated diene monomer unit part in the conjugated diene polymer. Be A well-known thing can be used as an acid catalyst used for cyclization reaction. For example, sulfuric acid; fluoromethanesulfonic acid, difluoromethanesulfonic acid, p-toluenesulfonic acid, xylenesulfonic acid, alkylbenzenesulfonic acid having an alkyl group having 2 to 18 carbon atoms, organic sulfonic acids such as anhydrides and alkyl esters thereof Compounds; Lewis acids such as boron trifluoride, boron trichloride, tin tetrachloride, titanium tetrachloride, aluminum chloride, diethylaluminum monochloride, ethyl ammonium chloride, aluminum bromide, antimony pentachloride, tungsten hexachloride, iron chloride and the like; Etc. can be mentioned. One of these acid catalysts may be used alone, or two or more thereof may be used in combination. Among them, organic sulfonic acid compounds are preferable, and p-toluenesulfonic acid and xylenesulfonic acid are more preferable. The amount of the acid catalyst used is usually 0.05 to 10 parts by mass, preferably 0.1 to 5 parts by mass, and more preferably 0.3 to 2 parts by mass, per 100 parts by mass of the conjugated diene polymer.

  The cyclization reaction is usually carried out by dissolving the conjugated diene polymer in a hydrocarbon solvent. The hydrocarbon solvent is not particularly limited as long as it does not inhibit the cyclization reaction, and examples thereof include aromatic hydrocarbons such as benzene, toluene, xylene and ethylbenzene; n-pentane, n-hexane, n-heptane, n Aliphatic hydrocarbons such as octane; alicyclic hydrocarbons such as cyclopentane and cyclohexane; and the like. The boiling point of these hydrocarbon solvents is preferably 70 ° C. or more. The solvent used for the polymerization reaction of the conjugated diene polymer and the solvent used for the cyclization reaction may be the same species. In this case, the cyclization reaction can be carried out following the polymerization reaction by adding an acid catalyst for the cyclization reaction to the polymerization reaction solution in which the polymerization reaction is completed. The amount of the hydrocarbon solvent used is such that the solid concentration of the conjugated diene polymer is usually 5 to 60% by mass, preferably 20 to 40% by mass.

  The cyclization reaction can be carried out under any pressure of pressure, reduced pressure and atmospheric pressure, but it is desirable to carry out under atmospheric pressure from the viewpoint of simplicity of operation. When the cyclization reaction is performed under a dry air stream, particularly under an atmosphere of dry nitrogen or dry argon, side reactions caused by moisture can be suppressed. The reaction temperature and reaction time in the cyclization reaction are not particularly limited. The reaction temperature is usually 50 to 150 ° C., preferably 70 to 110 ° C., and the reaction time is usually 0.5 to 10 hours, preferably 2 to 5 hours. After carrying out the cyclization reaction, the acid catalyst can be inactivated by a conventional method to remove the acid catalyst residue, and then the hydrocarbon solvent can be removed to obtain a solid conjugated diene polymer cyclized product. .

  The unsaturated bond reduction rate of the conjugated diene polymer cyclized product used in the present invention is preferably 10% or more. The unsaturated bond reduction rate is more preferably 30 to 75%, still more preferably 40 to 60%. The unsaturated bond reduction rate of the conjugated diene polymer cyclized product can be adjusted by appropriately selecting the amount of the acid catalyst in the cyclization reaction, the reaction temperature, the reaction time, and the like. When the unsaturated bond reduction rate of the conjugated diene polymer cyclized product is in the above range, the oxygen absorbability of the oxygen-absorbing resin layer becomes excellent.

Here, the unsaturated bond reduction rate is an index showing the degree to which unsaturated bonds are reduced by cyclization reaction in conjugated diene monomer unit parts in conjugated diene polymers, and the numerical value determined as follows: It is. That is, the ratio of the peak areas of protons directly bonded to double bonds to the peak areas of all protons in the conjugated diene monomer unit part in the conjugated diene polymer by proton NMR analysis, before and after the cyclization reaction, respectively Calculate and calculate the rate of decrease. Now, in the conjugated diene monomer unit in the conjugated diene polymer, all proton peak areas before cyclization reaction are SBT, peak areas of protons directly bonded to double bonds are SBU, all protons after cyclization reaction Assuming that the peak area is SAT and the peak area of protons directly bonded to double bonds is SAU, the peak area ratio (SB) of protons directly bonded to double bonds before the cyclization reaction is
SB = SBU / SBT
The peak area ratio (SA) of the proton directly bonded to the double bond after the cyclization reaction is
SA = SAU / SAT
Therefore, the unsaturated bond reduction rate can be obtained by the following equation.
Unsaturated bond reduction rate (%) = 100 × (SB-SA) / SB

  The weight average molecular weight of the cyclized conjugated diene polymer is usually 1,000 to 1,000,000, preferably 10,000 to 700,000, in terms of standard polystyrene equivalent determined by gel permeation chromatography. More preferably, it is 30,000 to 500,000. The weight average molecular weight of the conjugated diene polymer cyclized product can be adjusted by appropriately selecting the weight average molecular weight of the conjugated diene polymer to be subjected to cyclization. If the weight average molecular weight of the conjugated diene polymer cyclized product is too low, it may be difficult to form a film, and the mechanical strength may be lowered. When the weight-average molecular weight of the conjugated diene polymer cyclized material is too high, the solution viscosity in the cyclization reaction increases, which makes it difficult to handle, and the processability at the time of extrusion molding may be reduced. The amount of gel (toluene-insoluble matter) of the conjugated diene polymer cyclized product is usually 10% by mass or less, preferably 5% by mass or less, but it is particularly preferable to have substantially no gel. If the amount of gel is large, the smoothness of the film may be impaired.

  In the present invention, an antioxidant may be added to the conjugated diene polymer cyclized compound in order to secure the processing stability of the conjugated diene polymer cyclized compound. The amount of the antioxidant is usually in the range of 8,000 ppm or less, preferably 10 to 5,000 ppm, more preferably 50 to 3,000 ppm, based on the weight of the cyclized conjugated diene polymer. However, if the addition amount of the antioxidant is too large, the oxygen absorbability decreases, so it is necessary to appropriately adjust the addition amount in consideration of the stability at the time of processing.

  The antioxidant is not particularly limited as long as it is commonly used in the field of resin materials or rubber materials. Representative examples of antioxidants include hindered phenol type, phosphorus type and lactone type antioxidants. In addition, an amine light stabilizer (HALS) may be added. These antioxidants can also be used in combination of 2 or more types. Specific examples of hindered phenolic antioxidants include 2,6-di-t-butyl-p-cresol and pentaerythritol tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) Propionate], thiodiethylene bis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, N, N'-hexane-1,6-diylbis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionamide], diethyl [[3,5-bis (1,1-dimethylethyl)] ) -4-Hydroxyphenyl] methyl] phosphonate, 3,3 ′, 3 ′ ′, 5,5 ′, 5 ′ ′-hexa-t-butyl-a, a ′, a ′ ′-(mesitylene-2 4,6-triyl) tri-p-cresol, hexamethylene bis [3- (3,5-di-t-butyl) -4-hydroxyphenyl] propionate, tetrakis [methylene-3- (3,5-di-) t-Butyl-4-hydroxyphenyl) propionate] methane, n-octadecyl-3- (4′-hydroxy-3,5′-di-t-butylphenyl) propionate, 1,3,5-tris (3,5) -Di-t-butyl-4-hydroxybenzyl) -1,3,5-triazine-2,4,6 (1H, 3H, 5H) -trione, 2,4-bis- (n-octylthio) -6- (4-hydroxy-3,5-di-tert-butylanilino) -1,3,5-triazine, tris- (3,5-di-tert-butyl-4-hydroxybenzyl) -isocyanurate, 2-tert- The 6- (3'-t-Butyl-2'-hydroxy-5'-methylbenzyl) -4-methylphenyl acrylate, 2- [1- (2-hydroxy-3,5-di-t-phenyl) Ethyl] -4,6-di-t-pentylphenyl acrylate and the like can be mentioned.

  As phosphorus-based antioxidants, 2,2'-methylenebis (4,6-di-t-butylphenyl) octyl phosphite, tris (2,4-di-t-butylphenyl) phosphite, bisphosphite [2,4-bis (1,1-dimethylethyl) -6-methylphenyl] ethyl ester, tetrakis (2,4-di-t-butylphenyl) [1,1-biphenyl] -4,4′-diyl Bisphosphonite, bis (2,4-di-t-butylphenyl) pentaerythritol diphosphite, bis (2,6-di-t-butyl-4-methylphenyl) pentaerythritol diphosphite etc. it can. In addition, lactone-based antioxidants, which are reaction products of 5,7-di-t-butyl-3- (3,4-dimethylphenyl) -3H-benzofuran-2-one, etc. with o-xylene May be Examples of amine light stabilizers (HALS) include bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate and the like.

  Examples of the base resin of the oxygen-absorbing resin layer 3 include polyolefin resins, polyester resins, polyamide resins, polyvinyl chloride resins, polyacrylonitrile resins, and polyvinyl alcohol resins. Examples of polyolefin resins include polyethylene, polypropylene, ethylene-propylene copolymer, copolymer of ethylene or propylene (copolymer of ethylene or propylene and at least one of the following monomers: 1-butene, isobutene, Α-olefins such as 4-methyl-1-pentene, 1-hexene, 1-octene and the like; unsaturated carboxylic acids such as itaconic acid, methacrylic acid, acrylic acid and maleic anhydride, salts thereof, partial or complete esters thereof, Nitriles, their amides, their anhydrides; Vinyl formates, vinyl acetates such as vinyl acetate, vinyl propionate, vinyl propionate, vinyl butyrate, vinyl octanoate, vinyl dodecanoate, vinyl stearate, vinyl arachidonate, etc .; Vinylsilane compounds such as methoxysilane; not Sum sulfonic acid or salts thereof; alkylthiols; vinyl pyrrolidones and the like), poly-4-methyl-1-pentene, it can be mentioned poly-1-butene.

  Examples of polyester resins include polyethylene terephthalate, polybutylene terephthalate and polyethylene naphthalate.

  Examples of polyamide-based resins include polycaproamide (nylon-6), polyundecanamide (nylon-11), polylaurolactam (nylon-12), polyhexamethylene adipamide (nylon-6,6), poly Aliphatic polyamide homopolymers such as hexamethylene sebacamide (nylon-6, 10); caprolactam / laurolactam copolymer (nylon-6 / 12), caprolactam / aminoundecanoic acid copolymer (nylon-6 / 11) ), Caprolactam / ω-aminononanoic acid copolymer (nylon-6 / 9), caprolactam / hexamethylene adipamide copolymer (nylon-6 / 6, 6), caprolactam / hexamethylene adipamide / hexamethylene se Aliphatic poly such as bacamide copolymer (nylon-6 / 6,6 / 6,10) Bromide copolymer; poly-m-xylylene adipamide (MX- nylon) and aromatic polyamide of hexamethylene terephthalamide / hexamethylene isophthalamide copolymer (Nylon-6T / 6I), and the like. These polyamide resins (C2) can be used alone or in combination of two or more. Among these, polycaproamide (nylon-6), polyhexamethylene adipamide (nylon-6,6) and polycaproamide (nylon-6) -polyhexamethylene adipamide (nylon-6,6) The copolymer is preferable from the viewpoint of having appropriate gas permeability.

  Examples of polyvinyl chloride resins include homopolymers of vinyl chloride or vinylidene chloride, as well as copolymers with vinyl acetate, maleic acid derivatives, higher alkyl vinyl ethers and the like.

  Examples of polyacrylonitrile resins include homopolymers of acrylonitrile and copolymers with acrylic acid esters and the like.

  A polyvinyl alcohol resin saponifies a homopolymer of vinyl ester or a copolymer of vinyl ester and another monomer (in particular, a copolymer of vinyl ester and ethylene) using an alkali catalyst or the like. It is a resin obtained. Although vinyl acetate is mentioned as a typical compound as a vinyl ester, you may use other fatty acid vinyl esters (vinyl propionate, vinyl pivalate etc.).

  The degree of saponification of the vinyl ester component of the polyvinyl alcohol resin is preferably 90 mol% or more, more preferably 95 mol% or more, and particularly preferably 96 mol% or more. If the degree of saponification is less than 90 mol%, the gas barrier properties under high humidity are reduced. When the polyvinyl alcohol resin is ethylene-vinyl alcohol copolymer (EVOH), the thermal stability is insufficient if the degree of saponification is less than 90 mol%, and gels and the like are easily contained in the obtained molded article. Become. In addition, when polyvinyl alcohol-type resin consists of a mixture of 2 or more types of polyvinyl alcohol-type resin in which saponification degrees differ, let the average value calculated from mixed mass ratio be saponification degree.

  Among these polyvinyl alcohol-based resins, EVOH is preferable in that it can be melt-molded and has good gas barrier properties under high humidity, and EVOH having an ethylene content of 5 to 80 mol% is more preferable. If the ethylene content is less than 5 mol%, the gas barrier properties under high humidity may be reduced and the melt moldability may also be deteriorated. The ethylene content of EVOH is preferably 10 mol% or more, more preferably 15 mol% or more, and particularly preferably 20 mol% or more. On the other hand, if the ethylene content exceeds 80 mol%, sufficient gas barrier properties may not be obtained. The ethylene content is preferably 70 mol% or less, more preferably 60 mol% or less. The ethylene content and the degree of saponification of EVOH can be determined by nuclear magnetic resonance (NMR) method.

  EVOH may contain a small amount of units of monomers other than ethylene units and vinyl alcohol units as copolymerized units, as long as the object of the present invention is not impaired. Examples of the copolymerizable monomers include, for example, α-olefins such as propylene, 1-butene, isobutene, 4-methyl-1-pentene, 1-hexene and 1-octene; itaconic acid, methacrylic acid, acrylic acid Unsaturated carboxylic acids such as maleic anhydride, their salts, their partial or complete esters, their nitriles, their amides, their anhydrides; vinyltrimethoxysilane, vinyltriethoxysilane, vinyltri (β-methoxy-ethoxy) silane, Vinylsilane compounds such as γ-methacryloxypropyltrimethoxysilane; unsaturated sulfonic acids or salts thereof; alkylthiols; vinylpyrrolidones and the like.

  Also, the EVOH may be modified to impart flexibility to the EVOH. In this case, since the gas barrier property of the original EVOH is sufficiently high, it is also possible to make the degree of modification relatively high by emphasizing flexibility. As such a modified EVOH or a resin composition containing the same, the modified EVOH described in International Publication WO 03/072653 and a resin composition containing the same can be mentioned.

  The ratio of the oxygen absorbent composed of a cyclized conjugated diene polymer to the base resin in the resin composition constituting the oxygen-absorbing resin layer 3 may be appropriately determined according to the required performance, but If the amount of the oxygen absorbent composed of a cyclized diene polymer is too small, the permeation of oxygen may not be sufficiently prevented, which is not preferable. On the other hand, if the amount is too large, the gas permeability of the oxygen-absorbing resin layer 3 becomes too high, which causes deterioration in physical properties, change in hue, and the like due to oxidation of the oxygen absorbent composed of a cyclized conjugated diene polymer. It is not preferable because it may be easier.

  In consideration of the above points, the ratio of the amount of the oxygen absorbent composed of a cyclized conjugated diene polymer and the base resin in the resin composition constituting the oxygen-absorbing resin layer 3 is from the cyclized conjugated diene polymer When the total mass of the oxygen absorber and the base resin is 100% by mass, it is preferable to contain 1 to 50% by mass, more preferably 3 to 40% by mass, of an oxygen absorbent composed of a cyclized conjugated diene polymer. %, More preferably 5 to 30% by mass.

  There is no particular limitation on the method of preparing the oxygen-absorbing resin composition, and a conjugated diene polymer cyclized product, a gas barrier resin, and other resins and various additives optionally used are mixed by any method. do it. Specifically, the mixing can be carried out using a single-screw extruder or a multi-screw extruder such as a twin screw, a Banbury mixer, a roll, a kneader or the like. The mixing temperature is preferably in the range of 150 to 250.degree.

  The sealant 10 of the present invention has an oxygen-absorbing resin layer 3 and a food contact layer 4 and when the sealants are thermally bonded with the food contact layer 4 inside, the seal strength at 23 ° C. is 23 to 23 It is important that the seal strength is 100 N / 15 mm and 5 to 25 N / 15 mm at 90 ° C., and there is no particular limitation. As the polyolefin resin layer 1 according to one preferred embodiment of the sealant of the present invention shown in FIG. 1, the same polyolefin resin composition as the polyolefin resin constituting the food contact layer 4 may be used, and different polyolefins You may use a system resin composition.

  Further, as the adhesive resin layers 2a and 2b, thermoplastic resins can be used to bond the respective layers. Specifically, as the material of the adhesive resin layer, low density polyethylene resin, medium density polyethylene resin, high density polyethylene resin, linear low density polyethylene resin, ethylene / α-olefin polymerized using a metallocene catalyst Copolymer resin, ethylene / polypropylene copolymer resin, ethylene / vinyl acetate copolymer resin, ethylene / acrylic acid copolymer resin, ethylene / ethyl acrylate copolymer resin, ethylene / methacrylic acid copolymer resin , Ethylene / methyl methacrylate copolymer resin, ethylene / maleic acid copolymer resin, ionomer resin, polyolefin resin, unsaturated carboxylic acid, unsaturated carboxylic acid, unsaturated carboxylic anhydride, ester monomer, graft polymerization Or graph of copolymerized resin, maleic anhydride to polyolefin resin The modified resin can be used. In the present invention, one of these resins may be used alone, or two or more of these resins may be used in combination.

  The thicknesses of the food contact layer 4 and the oxygen-absorbing resin layer 3 constituting the sealant 10 of the present invention may be appropriately determined depending on the purpose. For example, the thickness of the food contact layer 4 can be 5 to 60 μm, and the thickness of the oxygen-absorbing resin layer 3 can be 5 to 40 μm. As shown in FIG. 1, when providing layers other than the food contact layer 4 and the oxygen-absorbing resin layer 3, for example, as shown in the drawing, when providing the polyolefin resin layer 1, its thickness is about 5 to 50 μm. The adhesive resin layers 2a and 2b can be 3 to 15 .mu.m. The thickness of the sealant 10 is preferably about 40 to 120 μm, and more preferably about 50 to 100 μm.

  The sealant 10 of the present invention can be suitably manufactured by coextrusion molding. The resin composition of each layer of the sealant 10 of the present invention is prepared, and then the resin composition is coextruded using, for example, a T-die coextruder, an inflation coextruder, for example, One layer is composed of a polyolefin resin layer, the second layer is an adhesive resin layer, the third layer is an oxygen-absorbing resin layer, the fourth layer is an adhesive resin layer, and the fifth layer is a food contact layer. Five layers of sealant can be produced.

  As one preferable embodiment of the sealant according to the present invention, a polyolefin resin layer 1, an adhesive resin layer 2a, an oxygen-absorbing resin layer 3, an adhesive resin layer 2b and a food contact layer 4 are sequentially laminated using FIG. Although the sealant described above has been described, in the sealant of the present invention, a barrier layer (not shown) that blocks oxygen, water vapor and the like may be further laminated, and a base material layer (not shown).

  Examples of the barrier layer include polyvinyl alcohol resins such as polyvinyl alcohol films and ethylene vinyl copolymer films, metal oxides such as alumina for base films such as polyethylene terephthalate, and silicon oxides such as silica. It is possible to cite a vapor deposited film in which a vapor deposited layer is laminated, and a film in which such a vapor deposited film is provided with a gas barrier coating film of a gas barrier composition containing a polyvinyl alcohol resin and / or an ethylene / vinyl alcohol copolymer. it can.

  The resin composition for forming each layer of the sealant 10 of the present invention may contain known additives such as a lubricant, an antioxidant, an antistatic agent, and a coloring agent as long as the intended purpose of the present invention is not impaired. Can be added as needed.

Next, the laminate of the present invention will be described.
The laminate of the present invention uses the above-mentioned sealant of the present invention as a sealant layer. A cross-sectional view of one preferred embodiment of the laminate of the present invention is shown in FIG. In the illustrated example, in the laminate 20, the base layer 11, the print layer 12, the adhesive layer 13, and the sealant layer 14 are sequentially laminated, but the print layer 12 and the adhesive layer 13 are not essential. It is provided appropriately as needed.

  The base material layer 11 is not particularly limited as long as it has heat resistance and is generally used as a food packaging material which is heated or cooked by a microwave oven. For example, stretched polyethylene terephthalate film, silica vapor deposited stretched polyethylene terephthalate film, alumina vapor deposited stretched polyethylene terephthalate film, stretched nylon film, silica vapor deposited stretched nylon film, alumina vapor deposited stretched nylon film, stretched polypropylene film, polyvinyl alcohol coated stretched polypropylene film, nylon 6 It may be a composite film in which one or two or more films such as / metaxylylenediamine nylon 6 co-pressed co-stretched film or polypropylene / ethylene-vinyl alcohol copolymer co-pressed co-stretched film are laminated. These base layers 11 preferably have heat resistance of 150 ° C. or higher, and have a thickness of 10 μm to 50 μm, preferably 10 μm to 30 μm.

The lamination of the base material layer 11 and the sealant layer 14 is not particularly limited as long as it is a coextrusion lamination method, a dry lamination method or the like. The adhesive layer 13 is made of an adhesive by lamination or an adhesive resin. In such a case, the adhesive for lamination may be, for example, one-component or two-component cured or non-cured vinyl-based, (meth) acrylic-based, polyamide-based, polyester-based, polyether-based, polyurethane-based, epoxy-based Adhesives for laminating such as solvent-based, rubber-based or other solvent-based, aqueous-type, or emulsion-type can be used. As a coating method of the adhesive for lamination, it can be applied by, for example, direct gravure roll coating method, gravure roll coating method, kiss coating method, reverse roll coating method, fonten method, transfer roll coating method, and other methods. As the coating ^{amount, 0.1g / m 2 ~10g / m} 2 ( dry) degree is ^{preferred, 1g / m 2 ~5g / m} 2 ( dry) degree is more preferred.

  In addition, as the adhesive resin in the adhesive layer, a thermoplastic resin can be used. Specifically, as the material of the adhesive layer, low density polyethylene resin, medium density polyethylene resin, high density polyethylene resin, linear low density polyethylene resin, co-polymerization with ethylene / α-olefin polymerized using a metallocene catalyst Polymer resin, ethylene-polypropylene copolymer resin, ethylene-vinyl acetate copolymer resin, ethylene-acrylic acid copolymer resin, ethylene-ethyl acrylate copolymer resin, ethylene-methacrylic acid copolymer resin, ethylene · Graft polymerization of methyl methacrylate copolymer resin, ethylene / maleic acid copolymer resin, ionomer resin, polyolefin resin with unsaturated carboxylic acid, unsaturated carboxylic acid, unsaturated carboxylic acid anhydride, ester monomer, or , Copolymerized resin and maleic anhydride grafted onto polyolefin resin Resin or the like can be used. One of these materials may be used alone, or two or more of these materials may be used in combination. The thickness of the adhesive layer is preferably about 10 μm to 30 μm.

  Furthermore, in the present invention, an intermediate layer (not shown) may be provided between the base material layer 11 and the sealant layer 14, and the intermediate layer is usually a packaging bag with only the base material layer 11 and the sealant layer 14. It is provided when the function can not be performed sufficiently. Such functions include gas barrier properties, mechanical toughness, flex resistance, puncture resistance, impact resistance, abrasion resistance, cold resistance, heat resistance, chemical resistance, etc., and are required as a packaging bag This is achieved by providing these functions as an intermediate layer. Examples of the base material used as the intermediate layer include polyethylene terephthalate, polyamide, polyolefins such as polyethylene and polypropylene, polyvinyl chloride, polycarbonate, polyvinyl alcohol, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer saponified, etc. Films or films coated with polyvinylidene chloride or films deposited with an inorganic substance such as silicon oxide or aluminum oxide, films of polyvinylidene chloride or the like, etc. You may use and may use it in combination of 2 or more types. In addition, as thickness of a base material, the function requested | required as a packaging bag should just be satisfy | filled, Comprising: It can select suitably as needed.

  In the present invention, when laminating each layer, for example, pretreatment such as corona treatment, ozone treatment, frame treatment, and the like can be performed as needed. Such surface pretreatment is carried out to improve adhesion and the like when laminating each layer, but as a method of improving the adhesion, for example, a primer coating agent is previously applied to the surface of a film or sheet of various resins. A layer, an undercoating agent layer, an anchor coating agent layer and the like may be optionally formed as a surface treatment layer.

Then, the packaging bag for microwave ovens of this invention is demonstrated.
The packaging bag for microwave ovens of this invention uses the laminated body of the said invention. For example, as a laminated body used for the packaging bag for microwave ovens of this invention, as shown in FIG. 2, the base material layer 11, the printing layer 12, the adhesive layer 13, and the sealant layer 14 were laminated | stacked one by one. A thing can be used suitably. As described above, the print layer 12 and the adhesive layer 13 are not essential layers but layers provided as needed as needed. In addition, an intermediate layer (not shown) may be provided between the sealant layer 14 and the base material layer 11 as necessary.

  FIG. 3 is a view showing an example of the packaging bag 100 for a microwave oven of the present invention, wherein (a) is a laminate constituting the packaging bag, (b) a plan view of the packaging bag, and (c) a perspective view of the packaging bag. And (d) is a cross-sectional view of the packaging bag. FIG. 4 is a view showing the shape of the U-shaped seal 109 in the packaging bag 100 for a microwave oven according to the present invention, and FIG. 5 is a cutout 111 formed in the unsealed portion 110 surrounded by the U-shaped seal 109. FIG. 6 is a cross-sectional view taken along the line X-X in FIG. 3, and FIG. 7 is an explanatory view showing dimensions of the packaging bag for the microwave oven of the present invention.

  As shown in FIG. 3A, the laminate constituting the packaging bag 100 for a microwave oven according to the present invention has a body (2 sheets) consisting of a rectangular laminate of the front surface 102 and the rear surface 103 and the bottom surface 104 reversed. And a bottom member (one sheet) folded in a V-shape. As shown in FIG. 3A, a bottom member (one sheet) in which the bottom surface 104 is folded in an inverted V shape is inserted into a body (two sheets) made of a square film of the front surface 102 and the rear surface 103, With the top portion seal portion 107 remaining, the peripheral portions of the front surface 102, the rear surface 103, and the bottom surface 104 are heat sealed to form a body seal portion 105 and a bottom seal portion 106, thereby forming a bag body. In the packaging bag 100 for a microwave oven of the present invention, the positions of the semicircular punch holes 101 formed on the left and right of the folded portion of the bottom member are formed 30 mm to 40 mm inward from the end, and the semicircular punch holes are formed. It is preferable that the front and rear body members be heat-welded through 101. As a result, after the content is filled in the packaging bag, the bottom portion is easily expanded back and forth by the weight of the content, and the self-standing stability is improved.

  In the packaging bag 100 for a microwave oven of the present invention, it is preferable that the U-shaped seal portion be provided in connection with the body seal portion 105 as shown in FIG. 3 (b). As a result, when heating is performed in a microwave oven, pressure is concentrated on the U-shaped seal portion 109, so sealing is peeled off from the edge portion of the U-shaped seal portion 109 and is formed in the unsealed portion 110. The steam generated from the contents can be promptly discharged out of the bag through the notch 111 and the like. In addition, when forming the U-shaped seal portion 109, there is also an advantage that the body seal portion 105 and the U-shaped seal portion 109 can be integrally seal-processed with good productivity.

  Although the U-shaped seal part 109 is not illustrated, it is not limited to the trunk part seal part 105, and the same effect can be obtained even if it is provided in connection with the top part seal part 107. When the U-shaped seal portion 109 is not connected to the body seal portion 105 but is formed independently, the pressure of the steam generated by the heating of the microwave oven is the pressure of the body seal portion 105 or the top seal portion. Since it passes between 107 and the independent seal part, it becomes difficult to apply pressure to the independent seal part efficiently, and it is not preferable because automatic opening does not occur smoothly. In addition, when the content is filled or in the process of circulation, the content gets in between the independent seal portion and the trunk portion seal portion 105 and an appearance defect occurs. Furthermore, since the seal processing is performed on the independent seal portion and the peripheral seal portion of the body seal portion 105 or the top seal portion 107 in two steps, the productivity of the seal processing is inferior.

  The position where the U-shaped seal portion 109 is formed is a U-shaped seal portion 109 from the center of the packaging bag, as shown in FIG. The position is such that the radius R3 of the circle in contact with the lowermost end of the circle is shorter than the radius R1 of the circle in contact with the inner edge of the body seal. If the radius R3 is longer than the radius R1 or the radius R2, the peeling and retreat of the seal due to the heat of the steam generated by heating and the rise of the internal pressure peels at the trunk seal portion 105 of the packaging bag, and the packaging bag is broken. The bag may leak the contents, which is not preferable.

  As shown in FIGS. 4A to 4C, the shape of the U-shaped seal portion forms a projecting end 113 in which the lower end of the seal portion is protruded. If the end 113 is formed, it is not limited to the U-shape, and may be trapezoidal or triangular. As a result, the internal pressure due to heating tends to concentrate and be applied to the projecting end 113, and peeling and retreating of the sealing portion proceeds reliably and smoothly starting from the projecting end 113, which is preferable for safety. On the other hand, if the U-shaped seal portion 109 has a circular shape or a semi-circular shape without corners, the internal pressure generated by heating is dispersed, and the pressure is greater for peeling back and retreat of the seal portion. Since it will be necessary, it will not be peeled off smoothly, and a larger pressure will be applied to parts other than the U-shaped seal part 109, which is not preferable.

  Further, by forming the unsealed portion 110 surrounded by the U-shaped seal portion 109, the formation of the notch 111 or the notch 112 formed in the unsealed portion 110 as compared with the case where the unsealed portion 110 is not formed. Even if the position is shifted, the distance at which the seal peels and retreats is constant, and when the peel reaches the unsealed portion 110, the notch 111 and the incision 112 formed in the unsealed portion 110 can be widely opened at a stretch Therefore, in the case of heating with a microwave oven, there is an advantage that reliable, stable and quick steam removal can be performed. If the non-sealed portion 109 surrounded by the U-shaped seal portion 109 is not formed and only the solid seal is used, the distance of the seal peeling and receding changes when the position formed by the notch 111 or the notch 112 is shifted. As a result, it is not preferable because stable seal peeling does not always occur. Further, since the notch 111 or the notch 112 is inside surrounded by the U-shaped seal portion 109 and the trunk portion seal portion 105, it is hygienic because the sealing property can be completely maintained in the distribution stage.

  Further, as another shape of the U-shaped seal portion 109, as shown in FIG. 4D, a notch or a notch is not formed in the unsealed portion 110 surrounded by the U-shaped seal portion. Alternatively, the unsealed portion 110 surrounded by the U-shaped seal portion 109 may be partially provided with the unsealed portion 110a in the trunk portion seal portion 105 to communicate with the outside. As a result, there is no need for a process for forming a notch or a notch, and the body seal part 105 or the top part seal part 107 and the U-shaped seal part 109 can be integrally heat sealed. Since the unsealed portions 110 and 110a can be formed, productivity can be greatly improved, and there is a risk that scraps generated at the time of a notch or a cut may adhere to or be mixed in the packaging bag. Because it does not have the advantage of excellent hygiene.

  When the content is liquid, the lower end of the seal portion 113 is positioned higher than the liquid level of the content at the position where the U-shaped seal portion 109 is formed, in the case of automatic opening by heating. It is necessary to prevent the contents from being spilled. FIG. 7 is an explanatory view showing dimensions of the packaging bag for the microwave oven of the present invention, and as shown in the drawing, as the seal width e of the U-shaped seal portion 109, about 2 mm to 5 mm has an internal pressure due to heating. It is preferable because the seal can be peeled off smoothly. If the seal width e of the U-shaped seal portion 109 is less than 2 mm, the seal strength of the seal portion is not preferable because it is unstable. If it exceeds 5 mm, peeling of the seal portion is difficult to occur due to the internal pressure rising by heating. It is not preferable because On the other hand, in the packaging bag 100 for a microwave oven of the present invention as shown in FIG. 3A, the seal width of the peripheral seal portion, that is, the seal width of the body seal portion 105, the bottom seal portion 106 and the top seal portion 107. As g, about 6 mm-about 20 mm are preferable in the meaning which prevents that a bag is torn by the pressure or impact added at the time of transport or storage.

  Further, the width of the unsealed portion 110 communicating the inside and the outside with the body sealing portion 105 and the like forms the unsealed portion 110 of about 1/5 to 3/5 with respect to the vertical dimension c of the U-shaped seal portion 109. By doing this, it is possible to smoothly discharge the vapor in the bag generated by heating to the outside of the bag without the contents spilling over. Specifically, it is preferable that the width of the unsealed portion 110 communicating the inside and the outside with the trunk seal portion 105 and the like is about 10 mm to 3 mm. If the width connecting the inside and the outside to the trunk seal portion 105 and the like is less than 1 mm, the steam inside the bag can not be smoothly discharged out of the bag, the internal pressure rises, and the packaging bag may be expanded, which is preferable. If the liquid level of the contents is lower than the steaming port beyond 3 mm, the contents may be easily spilled out of the steaming port after automatic opening, which is not preferable.

  The packaging bag 100 for microwave ovens according to the present invention, as shown in FIG. 3, uses the laminate 10 of the present invention, and the body has two side edge portions of the wall film of the front surface 102 and the rear surface 103 The seal portion 105 is formed by heat sealing with the body seal portion 105, and the U-shaped seal portion 109 is integrally formed on at least one side of the wall film in connection with the body seal portion 105, and the U-shaped seal portion A notch 111 or the like is provided in the unsealed portion 110 surrounded by 109 and communicated with the outside to form an easily excavable means, and further, a bottom surface 104 is formed in a gusset type formed by folding a film inwards. The portion 106 is heat-sealed with a cocoon-bottomed seal pattern, and the self-standing microwave packaging bag 100 according to the embodiment of the present invention can be manufactured. Preferably, a notch 114 is formed at the edge of the body seal portion 105 of the bag. In this case, it is preferred to use a tear film which is easy to tear in the transverse direction through the notch 114. Next, after filling the contents, the upper end is sealed, and the top seal portion 107 is sealed and sealed, and a packaging bag can be manufactured. In the above, as a method of heat sealing, it can carry out by publicly known methods, such as bar seal, rotation roll seal, belt seal, impulse seal, high frequency seal, ultrasonic seal etc., for example. In addition, although not shown as a holding means formed in the packaging bag 100 for microwave ovens of this invention, the seal | sticker part of the trunk | body part seal part 105 or the top seal part 107 may be formed wide and easy to hold.

  Next, as shown in FIG. 6, the notch 111 or the notch 112 formed in the U-shaped seal portion 109 may be provided so as to penetrate through the two members constituting the opposite body portion, but only on one side. It may be provided in Further, the notch 111 or the notch 112 can be formed by laser processing, punching, or the like. Next, the shape of the notch 111 or the notch 112 formed in the unsealed portion 110 surrounded by the U-shaped seal portion 109 is, as shown in FIG. , I-shaped, U-shaped, or the like. The number of notches 111 or notches 112 is not limited to one, and may be plural. By forming the notch 111 or the notch 112, the lower part of the seal peeling portion of the U-shaped seal portion 109 where the vapor filled in the bag is peeled off passes through the notch 111 or the notch 112 provided in the unsealed portion 110. Therefore, the internal pressure of the bag can be reduced and bursting can be avoided.

In the present invention, the contents are filled from the opening of the bag-like container main body having the opening at the upper end, and then the opening is sealed at the upper end by heat sealing or the like. Producing a packaging semi-product forming a packaging bag for a microwave oven, and thereafter subjecting the packaging semi-product to a heat treatment such as retort treatment or boiling treatment to produce a packaging bag for a microwave oven according to the present invention. Can. In this case, as a method for retort treatment or boiling treatment, for example, using a normal retort pot, temperature, about 95 ° C. to 135 ° C., preferably about 120 ° C., pressure, 1 to 4 Kgf / cm ² · G Preferably, a method of heat and pressure treatment for about 2.1 Kgf / cm ² · G, for about 5 minutes to 120 minutes, preferably for about 30 minutes, or at a temperature of 90 to 100 ° C., preferably 90 It can be carried out by a method such as boiling treatment in about 5 ° C., for about 5 minutes to 20 minutes, preferably for about 10 minutes. Moreover, in the packaging bag for microwave ovens of this invention, the contents can be heat-sterilized or heat-sterilized cooking etc. by retort process or boiling process. As a retort treatment method, a hot water storage type in which hot water set to a high temperature in advance is caused to flow into the retort pot to pressurize, a hot water spray type in which pressurized is performed by spraying hot water, and steam is jetted. Various methods are possible, such as steam-type pressurization by pressure.

  In addition, the packaging bag may be filled with liquid contents other than solid contents, for example, solid food such as frozen sweet potato, curry, soup, soy sauce, sauce, soup, spices, It can be filled and packaged with various liquid foods such as liquor, fruit juices, water, etc., food and drink, and can withstand boiling sterilization or retort sterilization, and can keep the bag in a standing state when eating food. It is possible to heat and cook for a predetermined time in the range, to quickly discharge the steam generated by heating, to automatically reduce the internal pressure, and in particular to be excellent in self-sustaining ability on the tray in the microwave oven It is possible to stably heat or cook without turning over while rotating, and it is excellent in the filling aptitude of the contents, excellent in the display effect at the store, and without the need for the die cutting process for cutting out the trimming part Those that can be well sealed processing and manufacturing efficiency.

Hereinafter, the present invention will be described in more detail using examples.
Example 1
<Production Example of Propylene-Ethylene Block Copolymer (A)>
After fully replacing a 200 L stirred autoclave with propylene, introduce 63 L of fully dehydrated and deoxygenated n-heptane, 27 g of diethylaluminum chloride and 9.0 g of a titanium trichloride catalyst (manufactured by Marubeni Solvay) It was introduced in a propylene atmosphere.

The first polymerization step was started by introducing propylene at a flow rate of 9.0 kg / h while keeping the hydrogen concentration at 3.5 vol% after raising the temperature of the autoclave to 65 ° C. After 180 minutes, the introduction of propylene was stopped, and after continuous polymerization for 90 minutes, the gas phase was purged to 0.2 kg / cm ² G to obtain propylene block (I) comprising propylene homopolymer. The

  In the second polymerization step, after lowering the temperature of the autoclave to 60 ° C., block copolymerization is carried out by introducing ethylene at a flow rate of 1.5 kg / h of propylene at a flow rate of 1.5 kg / h for 180 minutes. A slurry of block copolymer (A) was obtained.

  The obtained slurry was filtered and dried to obtain 31.6 kg of a propylene-ethylene block copolymer (A) powder. MFR (A) at 230 ° C. and 2.16 kg load of the obtained propylene-ethylene block copolymer powder is 0.8 g / 10 min, and the propylene homopolymer obtained in the first polymerization step MFR (I) of propylene block (I) consisting of was 8.4 g / 10 min. Moreover, the ethylene-propylene copolymer block (II) introduce | transduced in the propylene- ethylene block copolymer (A) in the 2nd polymerization process was 25 mass% of all the polymers.

<Production Example of Propylene-Ethylene Block Copolymer (B)>
After fully replacing a 200 L stirred autoclave with propylene, introduce 63 L of fully dehydrated and deoxygenated n-heptane, 27 g of diethylaluminum chloride and 9.0 g of a titanium trichloride catalyst (manufactured by Marubeni Solvay) It was introduced under the atmosphere.

The first polymerization step was started by introducing propylene at a flow rate of 9.0 kg / h while keeping the hydrogen concentration at 1.8%, after raising the temperature of the autoclave to 65 ° C. After 240 minutes, the introduction of propylene was stopped, and after continuous polymerization for 90 minutes, the gas phase was purged to 0.6 kg / cm ² G to obtain propylene block (III) comprising propylene homopolymer. The

  In the second polymerization step, after lowering the temperature of the autoclave to 60 ° C., copolymerization is carried out by introducing propylene at a flow rate of 2.0 kg / h and ethylene at a flow rate of 2.0 kg / h for 60 minutes. A slurry of block copolymer (B) was obtained.

  The obtained slurry was filtered and dried to obtain 35.9 kg of a propylene-ethylene block copolymer (B) powder. MFR (B) at 230 ° C. under a load of 2.16 kg of the obtained propylene-ethylene block copolymer (B) powder is 2.1 g / 10 min, and the propylene obtained in the first polymerization step The MFR (III) of propylene block (III) consisting of a homopolymer was 3.4 g / 10 min. In addition, the ethylene-propylene copolymer block (IV) introduced into BPP (B) in the second polymerization step was 10% by mass of all the polymers.

<Production Example of Polypropylene>
25% by mass of the above propylene-ethylene block copolymer (A) powder, 70% by mass of the propylene-ethylene block copolymer (B) powder, MFR is 6.8 g / 10 at 230 ° C. and 2.16 kg load An ethylene-butene-1 copolymer (containing 20% by mass of butene-1) was added in a proportion of 5% by mass, and melt-kneaded using an extruder to produce a polypropylene resin.

<Production example of oxygen-absorbing resin>
80 parts by mass of EVOH as a base resin of an oxygen-absorbing resin layer, and a conjugated diene polymer cyclized as an oxygen absorbent (a conjugated diene polymer having a diblock structure consisting of a polystyrene block and a polyisoprene block is cyclized to form a phenolic oxide 200 parts by weight of an inhibitor and 200 ppm by weight of a phosphorus-based antioxidant were dry-blended, and melt-kneaded using a twin-screw extruder while purging the inside of a cylinder with nitrogen, to produce an oxygen-absorbing resin.

<Example of production of laminated film>
First, a sealant of the type shown in FIG. 1 was produced. The above-mentioned polypropyne resin is used for the food contact layer 4 and the polyolefin-based resin layer 1, the above-mentioned oxygen-absorbing resin is used for the oxygen-absorbing resin layer 3, and the polyolefin-based adhesive resin (Modic (registered Trademark): These were supplied to a co-extruder using Mitsubishi Chemical Co., Ltd.) to produce a sealant. The thickness of each layer of the sealant is polyolefin resin layer 1 (15 μm) / adhesive resin layer 2a (5 μm) / oxygen absorbing resin layer 3 (20 μm) / adhesive resin layer 2b (5 μm) / food contact layer 4 (25 μm) ). Next, a 12 μm thick silica-deposited polyethylene terephthalate (PET) film, a 15 μm thick stretched nylon film, and a 70 μm thick sealant as described above are dry laminated with a two-component curable urethane adhesive to form transparent barrier PET ( A laminate of 12 μm) / adhesive / stretched nylon film (15 μm) / adhesive / sealant (70 μm) was produced.

<Production example of packaging bag for microwave oven>
The obtained laminate was cut to obtain 2 body members (155 mm × 147 mm) and 1 bottom member (80 mm × 147 mm). Next, the bottom member was folded back so that the sealant was on the inner side, and a semicircular punched hole with a diameter of 15 mm was formed on the right and left of the folded portion 30 mm inward from the end. After that, using a bag making machine, the sealant is folded back to the bottom side of the opposing front and rear body members so that the bottom member having a folded portion is inserted inside, and the content filling port The front and rear body members were sealed through the semicircular punch holes, leaving the upper end portion to be. The seal width was 10 mm. Further, the bag body was manufactured by thermally bonding the round bottom seal portion to the body member and the bottom member with a seal width of 5 mm. Furthermore, a U-shaped seal portion (long dimension: 25 mm, horizontal dimension: 15 mm, seal width: 3 mm, notch diameter 8 mm) is formed on one side of the body seal portion, and the packaging bag for free standing microwave oven (outside dimension, 155 mm in height and 147 mm in width) were produced.

Example 2
A packaging bag for a self-supporting microwave was produced in the same manner as in Example 1 except that nylon 6 (85%)-nylon 66 (15%) copolymer was used as the base resin of the oxygen-absorbing resin layer 3 did.

Example 3
A self-supporting microwave packaging bag was produced in the same manner as in Example 1 except that nylon 6 was used as the base resin of the oxygen-absorbing resin layer 3.

Example 4
The thickness of each layer of the sealant is as follows: polyolefin resin layer 1 (15 μm) / adhesive resin layer 2a (5 μm) / oxygen absorbing resin layer 3 (15 μm) / adhesive resin layer 2b (5 μm) / food contact layer 4 (30 μm) A packaging bag for a self-supporting microwave was obtained in the same manner as in Example 1 except that the above was used.

Example 5
Polyolefin resin layer 1 (10 μm) / adhesive resin layer 2a (7.5 μm) / oxygen absorbing resin layer 3 (25 μm) / adhesive resin layer 2b (7.5 μm) / food contact thickness of each layer of the sealant A self-standing microwave packaging bag was obtained in the same manner as in Example 1 except that the layer 4 (20 μm) was used.

Example 6
The thickness of each layer of the sealant is as follows: polyolefin resin layer 1 (10 μm) / adhesive resin layer 2a (5 μm) / oxygen absorbing resin layer 3 (25 μm) / adhesive resin layer 2b (5 μm) / food contact layer 4 (5 μm) A packaging bag for a self-supporting microwave was obtained in the same manner as in Example 1 except that the above was used.

Example 7
The thickness of each layer of the sealant is as follows: polyolefin resin layer 1 (5 μm) / adhesive resin layer 2a (5 μm) / oxygen absorbing resin layer 3 (25 μm) / adhesive resin layer 2b (5 μm) / food contact layer 4 (60 μm) A packaging bag for a self-supporting microwave was obtained in the same manner as in Example 1 except that the above was used.

Comparative Example 1
A 70 μm film was produced as a single layer of the above polypropylene resin as a sealant, and this was used as a sealant layer to produce a self-standing microwave packaging bag in the same manner as in Example 1 except that a laminate was produced.

Comparative Example 2
A self-supporting microwave packaging bag was produced in the same manner as in Example 1 except that a single-layer film 70 μm of a general-purpose polypropylene resin other than the above was produced as a sealant and this was used as a sealant layer. did.

Comparative Example 3
As a base resin of the oxygen-absorbing resin layer 3, 80 parts by mass of general-purpose polypropylene resin other than the above, and 20 parts by mass of iron-based oxygen absorbent general-purpose as an oxygen absorbing material are dry blended, using a twin screw extruder The mixture was melt-kneaded while purging with nitrogen to produce an oxygen-absorbing resin. The thickness of each layer of the sealant was set to polyolefin resin layer 1 (20 μm) / oxygen absorbing resin layer 3 (25 μm) / food contact layer 4 (25 μm), and adhesive resin layers 2a and 2b were not provided. A self-standing microwave packaging bag was produced in the same manner as in Example 1 except for the above.

<Measurement of heat seal strength>
The heat seal strength of the thermal bond between the sealant layers of each of the self-supporting microwave packaging bags was measured. The measurement was performed using a tensile tester (manufactured by ORIENTEC Co., Ltd.), and T-peel was performed to measure peel strength. The measurement condition was a tensile speed of 300 mm / min. The obtained results are shown in Table 1.

<Evaluation of shelf life>
200g of meat sauce is put in the obtained packaging bag as contents, the upper end is sealed and sealed, retorted at 120 ° C for 30 minutes, and stored at 60 ° C for 1 month, due to oxidative degradation of the contents Color change (browning) was visually confirmed. The obtained results are shown in Table 1.

<Microwave oven evaluation>
Add 200g of miso soup as contents into the obtained packaging bag, seal the upper end and seal it, heat the one that has been retorted at 120 ° C for 30 minutes, and heat it with a 500W microwave while the packaging bag is standing Checked whether there were any problems during cooking. The obtained results are shown in Table 1.

  Since the packaging bag for microwave ovens of the present invention is excellent in oxygen barrier property, the flavor of the contents is not impaired. Moreover, after heating in a microwave oven, it peels off from the tip of the U-shaped seal part after about 1 minute and 20 seconds, and the steam quickly escapes from the notch formed in the unsealed part in the U-shaped seal part. It was possible to take out the contents safely without spilling anything. Furthermore, the packaging bag for the microwave oven of the present invention can be cooked with high self-standing stability without being tumbled while being heated by the microwave oven.

DESCRIPTION OF SYMBOLS 1 polyolefin resin layer 2a, 2b adhesive resin layer 3 oxygen absorptive resin layer 4 food contact layer 10 sealant 11 base material layer 12 printing layer 13 adhesive layer 14 sealant layer 20 laminated body 100 packaging bag for microwave oven 101 semicircular shape Punch hole 102 front surface 103 back surface 104 bottom surface 105 body seal portion 106 bottom seal portion 107 top seal portion 108 bottom material cutaway portion 109 U-shaped seal portion 110 unsealed portion 111 notch 112 notch 113 projecting end 114 notch

Claims (4)

It is a sealant which has a polyolefin resin layer / adhesive resin layer / non-ferrous oxygen absorbing resin layer / adhesive resin layer / food contact layer in this order,
When the sealants are thermally bonded with the food contact layer inside, the seal strength at 23 ° C. is 23 to 100 N / 15 mm, and the seal strength at 90 ° C. is 5 to 25 N / 15 mm,
The nonferrous oxygen-absorbing resin layer is composed of a resin composition containing an oxygen absorbent consisting of a conjugated diene polymer cyclized and a base resin, and an oxygen absorbent consisting of the conjugated diene polymer cyclized and the base When the total mass with the resin is 100% by mass, it contains more than 5% by mass and 30% by mass or less of the oxygen absorbent composed of the above-mentioned conjugated diene polymer cyclized product,
The food contact layer comprises a propylene-ethylene block copolymer (A), a propylene-ethylene block copolymer (B), and an ethylene-butene-1 copolymer containing 15% by mass or more of butene-1. A resin composition comprising: propylene block (I) 65, wherein the propylene-ethylene block copolymer (A) is a propylene homopolymer or a propylene-ethylene copolymer having an ethylene content of 2% by mass or less And 85% by mass, and 15 to 35% by mass of ethylene-propylene copolymer block (II) having an ethylene content of 20 to 95% by mass, and the propylene-ethylene block copolymer (B) has a propylene single weight Propylene block (III) 85 to 85 composed of a combined or propylene-ethylene copolymer having an ethylene content of 2% by mass or less And 5 wt%, an ethylene content of 20 to 95 wt% ethylene - consists propylene copolymer block (IV) a resin composition containing 5 to 15 wt%,
The content of the propylene-ethylene block copolymer (A) is 25 to 50% by mass, and the content of the propylene-ethylene block copolymer (B) is 25 to 70 for the resin composition constituting the food contact layer. A sealant characterized in that the content of the ethylene-butene-1 copolymer is in the range of 5 to 30% by mass.   The sealant of claim 1 wherein the sealant is produced by coextrusion.   A laminate comprising the sealant according to claim 1 or 2.   A packaging bag for a microwave oven, characterized in that the laminate according to claim 3 is used.

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