JP2010149380A - Polyamide-based multilayered film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyamide-based multilayered film showing excellent thermal dimensional stability, and excellent adhesion between layers even under a dry condition or a humid condition. <P>SOLUTION: The polyamide-based multilayered film has at least three layers of a sulfone group-containing polyester layer (layer C1), a polyamide-based copolymer layer (layer B1), and an aliphatic polyamide layer (layer A) in this order. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a polyamide-based multilayer film having excellent dimensional stability against heat and excellent adhesion between layers even in a dry state and a wet state.

  Conventionally, a polyamide-based multilayer film containing a nylon resin has been widely used in various fields as a film having gas barrier properties, toughness, pinhole resistance and the like.

  Although this polyamide-based multilayer film has the excellent characteristics as described above, for example, when used for packaging films for foods, etc., the odor of the contents leaks or the packaging film absorbs moisture by contact with water. There was a problem that the dimensions of the change. This is not preferable because it leads to deterioration of contents and a decrease in commercial value.

  Therefore, the packaging film is required to have high fragrance retention, dimensional stability against moisture absorption, moisture resistance, and the like. In particular, when used as a packaging film for more severe boil processing and retort processing, higher moisture resistance, dimensional stability against moisture absorption and dimensional stability against heat are required.

  As a material satisfying such required quality, a polyamide-based multilayer film is disclosed in which an adhesive layer made of a sulfone group-containing polyester is provided between a polyamide layer and a polyester layer.

However, although the disclosed polyamide-based multilayer film is excellent in thermal dimensional stability and hygroscopic dimensional stability, it can be used between the adhesive layer and the polyamide layer in water and in ultrahigh humidity during boil treatment and retort treatment. There was a problem that the interlaminar strength was lowered and peeled off easily.
JP 2008-1000049 A

  The main object of the present invention is to provide a polyamide-based multilayer film that is excellent in dimensional stability against heat and excellent in adhesion between layers even in a dry state and a wet state.

  As a result of intensive studies in view of the above problems, the present inventors have found that at least 3 of a sulfone group-containing polyester layer (C1 layer), a polyamide copolymer layer (B1 layer), and an aliphatic polyamide layer (A layer). It has been found that by having the layers in this order, a polyamide-based multilayer film in which the above-mentioned problems are solved can be obtained. The present invention has been completed based on such findings.

  That is, the present invention relates to the following polyamide-based multilayer film, packaging bag and package.

  Item 1. A polyamide multilayer film having at least three layers of a sulfone group-containing polyester layer (C1 layer), a polyamide copolymer layer (B1 layer) and an aliphatic polyamide layer (A layer) in this order.

  Item 2. A polyamide-based multilayer film having at least four layers in this order: a crystalline polyester layer (D1 layer), a sulfone group-containing polyester layer (C1 layer), a polyamide copolymer layer (B1 layer), and an aliphatic polyamide layer (A layer) .

  Item 3. Crystalline polyester layer (D1 layer), sulfone group-containing polyester layer (C1 layer), polyamide copolymer layer (B1 layer), aliphatic polyamide layer (A layer), polyamide copolymer layer (B2 layer) and A polyamide-based multilayer film having at least 6 layers of a sulfone group-containing polyester layer (C2 layer) in this order.

  Item 4. Crystalline polyester layer (D1 layer), sulfone group-containing polyester layer (C1 layer), polyamide copolymer layer (B1 layer), aliphatic polyamide layer (A layer), polyamide copolymer layer (B2 layer), A polyamide-based multilayer film having at least 7 layers of a sulfone group-containing polyester layer (C2 layer) and a crystalline polyester layer (D2 layer) in this order.

  Item 5. Item 5. The polyamide multilayer film according to any one of Items 1 to 4, wherein the total thickness of the polyamide multilayer film is 10 to 80 µm.

  Item 6. Item 6. The total thickness of the polyamide layers ((A) layer, (B1 layer) and (B2 layer)) is 30 to 95% with respect to the total thickness of the polyamide-based multilayer film, Polyamide-based multilayer film.

  Item 7. Item 7. A polyamide-based multilayer film obtained by biaxially stretching the polyamide-based multilayer film according to any one of Items 1 to 6.

  Item 8. Item 8. A packaging film obtained by laminating a seal layer on one surface of the polyamide-based multilayer film according to any one of Items 1 to 7.

  Item 9. Item 9. A packaging bag obtained by making the packaging film of Item 8 into a bag shape and heat-sealing the sealing layer surfaces.

  Item 10. Item 10. A package formed by filling the packaging bag according to Item 9.

  The polyamide-based multilayer film of the present invention is excellent in dimensional stability against heat and excellent in adhesion between layers in a dry state and a wet state. The polyamide-based multilayer film of the present invention having such excellent characteristics is suitably used as a packaging film.

1. Polyamide-based multilayer film Hereinafter, each configuration of the polyamide-based multilayer film of the present invention will be described in detail. Hereinafter, the polyamide-based multilayer film may be simply referred to as a multilayer film.

  The polyamide-based multilayer film of the present invention has at least three layers in this order: a sulfone group-containing polyester layer (C1 layer), a polyamide-based copolymer layer (B1 layer), and an aliphatic polyamide layer (A layer). In addition, you may have not only these three layers but another layer.

3-layer film <(A) layer>
The (A) layer imparts functions such as dimensional stability to heat to the multilayer stretched film of the present invention.

  The layer (A) contains an aliphatic polyamide as a main component excluding a polyamide-based copolymer described later. In the layer (A), an aliphatic polyamide is an essential component, but other polyamide components (polyamide copolymers, aromatic polyamides, etc.) and known flex resistance improvements are within the range not impairing the effects of the present invention. Agents, inorganic or organic additives and the like can also be blended.

  An aliphatic polyamide is a polyamide mainly composed of an aliphatic chain skeleton. Although it does not limit as a manufacturing method of aliphatic polyamide, It can obtain by polycondensation of diamine and a dibasic acid, ring-opening polymerization of lactam, polycondensation of aminocarboxylic acid, etc. Specific examples of the aliphatic polyamide include polycapramide (nylon-6), poly-ω-aminoheptanoic acid (nylon-7), poly-ω-aminononanoic acid (nylon-9), polyundecanamide (nylon-11). ), Polylauryl lactam (nylon-12), polyethylenediamine adipamide (nylon-2,6), polytetramethylene adipamide (nylon-4,6), polyhexamethylene adipamide (nylon-6,6) ), Polyhexamethylene sebamide (nylon-6,10), polyhexamethylene dodecamide (nylon-6,12), polyoctamethylene adipamide (nylon-8,6), polydecamethylene adipamide ( Nylon-10,8) etc. can be illustrated. These aliphatic polyamides may be used alone or in combination of two or more.

  Among these, nylon-6, nylon-6, 6 and the like are preferable, and nylon-6 is more preferable.

  Moreover, the polyamide-type copolymer which is another polyamide component includes a copolymer of aliphatic nylon such as nylon-6 and other components. Preferably, caprolactam / lauryl lactam copolymer (nylon-6 / 12), caprolactam / ω-aminononanoic acid copolymer (nylon-6 / 9), which are copolymers of nylon-6 and other nylon components , Caprolactam / hexamethylenediammonium adipate copolymer (nylon-6 / 6,6), ethyleneammonium adipate / hexamethylenediammonium adipate / hexamethylenediammonium sebacate copolymer (nylon-6 / 6,6 / 6) , 10). Specific examples include UBE nylon 5023B (manufactured by Ube Industries, Ltd.), UBETERPALEX 6434B (manufactured by Ube Industries, Ltd.), and the like.

  When the aliphatic polyamide and the polyamide-based copolymer are combined, the layer (A) contains an aliphatic polyamide (particularly nylon-6 or nylon-6,6, especially nylon-6) as a main component. ) The layer contains aliphatic polyamide in an amount of about 60 to 100% by weight, preferably about 70 to 100% by weight, more preferably about 80 to 100% by weight. Further, the (A) layer contains a polyamide-based copolymer in an amount of about 0 to 40% by weight, preferably about 0 to 30% by weight, more preferably about 0 to 20% by weight.

  Moreover, as an aromatic polyamide which is another polyamide component, for example, aromatic diamines such as metaxylenediamine and paraxylenediamine, and adipic acid, suberic acid, sebacic acid, cyclohexanedicarboxylic acid, terephthalic acid, isophthalic acid, etc. Examples thereof include crystalline aromatic polyamides obtained by polycondensation reaction with dicarboxylic acid or a derivative thereof. A crystalline aromatic polyamide such as polymetaxylene adipamide (MXD-nylon) is preferable. Specific examples include S-6007 and S-6011 (both manufactured by Mitsubishi Gas Chemical Co., Inc.).

  Alternatively, amorphous aromatic polyamide (amorphous) obtained by polycondensation reaction of aliphatic diamines such as hexamethylenediamine and trimethylhexamethylenediamine with dicarboxylic acids such as terephthalic acid, isophthalic acid, adipic acid and azelaic acid or derivatives thereof Nylon). Preferred is a copolymer of hexamethylenediamine-terephthalic acid-hexamethylenediamine-isophthalic acid. Specific examples include Sealer PA3426 (Mitsui / DuPont Polychemical Co., Ltd.), Novamid X21 (Mitsubishi Engineering Plastics Co., Ltd.), and the like.

  Preferred combinations of aliphatic polyamide and aromatic polyamide include a combination of nylon-6 and MXD-nylon, and a combination of nylon-6 and amorphous aromatic polyamide (amorphous nylon).

  When combining an aliphatic polyamide and an aromatic polyamide, the layer (A) contains an aliphatic polyamide (particularly nylon-6 or nylon-6,6, especially nylon-6) as a main component. The aliphatic polyamide is contained in an amount of about 75 to 100% by weight, preferably about 80 to 100% by weight, more preferably about 85 to 100% by weight. The layer (A) contains about 0 to 25% by weight of aromatic polyamide, preferably about 0 to 20% by weight, more preferably about 0 to 15% by weight.

<(B1) layer>
The (B1) layer gives the multilayer stretched film of the present invention functions such as adhesion to the (C1) layer described later.

  The (B1) layer contains a polyamide-based copolymer as a main component. In the layer (B1), the polyamide-based copolymer is an essential component, but other polyamide components, known flex resistance improvers, inorganic or organic additives, etc. are blended within the range not impairing the effects of the present invention. You can also

  Examples of the polyamide copolymer include copolymers of aliphatic nylon such as nylon-6 and other components. Preferably, caprolactam / lauryl lactam copolymer (nylon-6 / 12), caprolactam / ω-aminononanoic acid copolymer (nylon-6 / 9), which are copolymers of nylon-6 and other nylon components , Caprolactam / hexamethylenediammonium adipate copolymer (nylon-6 / 6,6), ethyleneammonium adipate / hexamethylenediammonium adipate / hexamethylenediammonium sebacate copolymer (nylon-6 / 6,6 / 6) , 10). Specific examples include UBE nylon 5023B (manufactured by Ube Industries, Ltd.), UBETERPALEX 6434B (manufactured by Ube Industries, Ltd.), and the like. These polyamide copolymers may be used alone or in combination of two or more.

  Further, as other polyamide components, nylon-6, nylon-6, 6, etc. described in the above <(A) layer> can be used.

  The layer (B1) contains a polyamide-based copolymer (particularly a copolymer of nylon-6 and other nylon components, especially nylon-6 / 6, 6) as a main component. Is preferably about 80 to 100% by weight, preferably about 90 to 100% by weight.

<(C1) layer>
The (C1) layer contains a sulfone group-containing polyester as a main component. By using the sulfone group-containing polyester, the dimensional stability against heat and the adhesiveness with the (B1) layer are dramatically improved.

  The sulfone group-containing polyester, for example, polycondenses a dicarboxylic acid containing a sulfone group and / or a diol containing a sulfone group in addition to a dicarboxylic acid and a diol containing no sulfone group when the polyester is polycondensed. Can be obtained.

  Examples of the dicarboxylic acid used at this time include o-phthalic acid, terephthalic acid, isophthalic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, octyl succinic acid, cyclohexanedicarboxylic acid, naphthalenedicarboxylic acid, fumaric acid, maleic acid. Acid, itaconic acid, decamethylene carboxylic acid, anhydrides and lower alkyl esters thereof, 5-sulfoisophthalic acid, 2-sulfoisophthalic acid, 4-sulfoisophthalic acid, 3-sulfophthalic acid, dialkyl 5-sulfoisophthalate, 2 -Dialkyl sulfosulfophthalate, dialkyl 4-sulfoisophthalate, dialkyl 3-sulfoisophthalate, and sulfo group-containing dicarboxylic acids such as sodium salts and potassium salts thereof.

  Examples of the diol include ethylene glycol, 1,3-propanediol, 1,4-butanediol, diethylene glycol, 1,5-pentanediol, 1,6-hexanediol, dipropylene glycol, triethylene glycol, and tetraethylene glycol. 1,2-propanediol, 1,3-butanediol, 2,3-butanediol, neopentyl glycol (2,2-dimethylpropane-1,3-diol), 1,2-hexanediol, 2,5 -Aliphatic diols such as hexanediol, 2-methyl-2,4-pentanediol, 3-methyl-1,3-pentanediol, 2-ethyl-1,3-hexanediol; 2,2-bis (4 -Hydroxycyclohexyl) propane, 2,2-bis (4-hydroxycyclohex) E) Alkylene oxide adduct of propane, alicyclic diols such as 1,4-cyclohexanediol and 1,4-cyclohexanedimethanol; 1,3-dihydroxybutanesulfonic acid, 1,4-dihydroxybutanesulfonic acid, etc. A sulfone group containing diol etc. are mentioned.

  Specific examples of the sulfone group-containing polyester include terephthalic acid (99.5 to 90 mol%) and 5-sodium sulfoisophthalic acid (0.5 to 10 mol%), which are derived from a diol. Examples include sulfoisophthalic acid copolymerized polyethylene terephthalate whose component is ethylene glycol. In the sulfone group-containing polyester, the copolymerization ratio of the dicarboxylic acid and / or diol containing a sulfone group is 0.5 to 20 mol%, preferably 1 to 10 mol%, based on the total dicarboxylic acid and / or diol component. is there. The intrinsic viscosity is 0.2 to 0.9 dl / g, preferably 0.3 to 0.8 dl / g. In addition, as the sulfone group-containing polyester, a commercially available one may be used, or a person skilled in the art can easily produce it.

  In addition, the (C1) layer may contain other resins having compatibility with the above-described sulfone group-containing polyester as necessary, as long as the effects of the present invention are not adversely affected. Examples of the resin compatible with the sulfone group-containing polyester include a polyester resin that does not contain a sulfone group. In this case, the content of the other resin is preferably less than 50% by weight based on the weight of the (C1) layer. Further, the content of the sulfone group-containing polyester is 50% by weight or more, preferably 80% by weight or more based on the weight of the (C1) layer.

4-layer film polyamide based multilayer film of the present invention, the above (C1) layer, (B1) layer and (A) may be configured comprising only three layers of layers, but further have other layers Good.

  For example, a crystalline polyester layer (D1 layer) may be provided outside the (C1) layer, and a four-layer film comprising (D1) layer / (C1) layer / (B1) layer / (A) layer may be used. In addition, you may have another layer instead of having only these four layers. Thus, by providing the (D1) layer, it is possible to further improve the dimensional stability against heat and the adhesion between each layer in a wet state.

<(D1) layer>
The (D1) layer contains crystalline polyester as a main component.

  Examples of the crystalline polyester constituting the (D1) layer include those obtained by polycondensation of a dicarboxylic acid not containing a sulfone group and a diol not containing a sulfone group.

  Examples of the dicarboxylic acid not containing a sulfonic group include o-phthalic acid, terephthalic acid, isophthalic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, octyl succinic acid, cyclohexanedicarboxylic acid, naphthalenedicarboxylic acid, fumaric acid, Examples include maleic acid, itaconic acid, decamethylene carboxylic acid, anhydrides and lower alkyl esters thereof.

  Examples of the diol not containing a sulfone group include ethylene glycol, 1,3-propanediol, 1,4-butanediol, diethylene glycol, 1,5-pentanediol, 1,6-hexanediol, dipropylene glycol, and triethylene. Glycol, tetraethylene glycol, 1,2-propanediol, 1,3-butanediol, 2,3-butanediol, neopentyl glycol (2,2-dimethylpropane-1,3-diol), 1,2-hexane Aliphatic diols such as diol, 2,5-hexanediol, 2-methyl-2,4-pentanediol, 3-methyl-1,3-pentanediol, 2-ethyl-1,3-hexanediol; 2-bis (4-hydroxycyclohexyl) propane, 2,2-bis (4 Hydroxycyclohexyl) alkylene oxide adducts of propane, 1,4-cyclohexane diol, alicyclic diols such as 1,4-cyclohexanedimethanol.

  Among these, polyethylene terephthalate (PET) composed of terephthalic acid as the dicarboxylic acid and ethylene glycol as the diol is preferable.

  In addition, the (D1) layer may contain other resin having compatibility with the crystalline polyester as necessary, as long as the effect of the present invention is not adversely affected. Examples of the resin that is compatible with the crystalline polyester include amorphous polyester. Amorphous polyester is polyester or the like in which no heat of fusion is observed in differential scanning calorimetry based on JIS K7121. Although it will not specifically limit if it is polyester which has such a characteristic, As a specific example, the component derived from dicarboxylic acid is terephthalic acid, the component derived from diol is ethylene glycol (20-80 mol%) and cyclohexane dimethanol ( 80-20 mol% of polyester; the component derived from dicarboxylic acid is terephthalic acid (20-80 mol%) and isophthalic acid (80-20 mol%), and the component derived from diol is ethylene glycol. Is preferred. In this case, the content of the other resin is preferably less than 50% by weight with respect to the weight of the (D1) layer. Moreover, content of the said crystalline polyester (especially PET) is 50 weight% or more with respect to the weight of (D1) layer, Preferably it is 80 weight% or more.

  Since the (D1) layer is usually the outermost layer, known inorganic or organic additives and the like can be appropriately blended as necessary within a range not impairing the effects of the present invention. As an inorganic or organic additive, an antiblocking agent, a nucleating agent, a water repellent, an antioxidant, a heat stabilizer, a lubricant, an antistatic agent, a colorant, a pigment, a dye, and the like can be appropriately blended.

In four-layer film of 6-layer film above, the outer layer (A), further, it provided a polyamide copolymer layer (B2 layer) and sulfone group-containing polyester layer (C2-layer) in this order, (D1) layer / It is good also as a 6-layer film which consists of (C1) layer / (B1) layer / (A) layer / (B2) layer / (C2) layer. In addition, you may have not only these 6 layers but another layer. In this manner, by providing the (B2) layer and the (C2) layer, a structure that hardly curls can be obtained.

  In addition, the specific example, compounding quantity, etc. which comprise (B2) layer can be made the same as that of (B1) layer, and the specific example, compounding quantity, etc. which comprise (C2) layer are the same as (C1) layer. Can be. Further, the types and blending amounts of the resins in the (B1) layer and the (B2) layer, and the (C1) layer and the (C2) layer may be the same or different. In general, from the viewpoint of simplicity of multilayer film production, it is preferable to use the same kind and the same proportion of resin in the B1) layer and the (B2) layer, and the (C1) layer and the (C2) layer.

7-layer film In the 6-layer film, a crystalline polyester layer (D2 layer) is further provided outside the (C2) layer, and (D1) layer / (C1) layer / (B1) layer / (A) layer It is good also as a 7-layer film which consists of / (B2) layer / (C2) layer / (D2) layer. In addition, you may have not only these seven layers but another layer. Thus, by providing the (D2) layer, not only can the dimensional stability against heat and the dimensional stability against wetting be further improved, but the structure of the film can be made symmetrical to make the structure more difficult to curl. . Moreover, since both surfaces become crystalline polyester, it is preferable from a heat resistant point.

Layer Structure The total thickness of the polyamide-based multilayer film of the present invention is about 10 to 80 μm, preferably about 12 to 60 μm. In such a range, the film productivity and the unit sales price are preferable.

  In the three-layer film, the thickness of each layer is preferably (C1) layer (1 to 20 μm) / (B1) layer (0.5 to 10 μm) / (A) layer (8.5 to 75 m).

  In the four-layer film, each layer has a thickness of (D1) layer (1 to 20 μm) / (C1) layer (0.5 to 10 μm) / (B1) layer (0.5 to 10 μm) / (A) layer (8 ˜75 μm) is preferable.

  In the 6-layer film, each layer has a thickness of (D1) layer (1 to 20 μm) / (C1) layer (0.5 to 10 μm) / (B1) layer (0.5 to 10 μm) / (A) layer (6 .5 to 75 μm) / (B2) layer (0.5 to 10 μm) / (C2) layer (1 to 10 μm).

  In the seven-layer film, the thickness of each layer is (D1) layer (1 to 20 μm) / (C1) layer (0.5 to 10 μm) / (B1) layer (0.5 to 10 μm) / (A) layer (6 ˜75 μm) / (B2) layer (0.5 to 10 μm) / (C2) layer (0.5 to 10 μm) / (D2) layer (1 to 20 μm).

  In any of the three-layer film, the four-layer film, the six-layer film, and the seven-layer film, the total thickness of the polyamide layer ((A) layer, (B1) layer, and (B2) layer) is the total thickness of the polyamide-based multilayer film. Is about 30 to 95%, preferably about 40 to 90%.

  In the multilayer stretched film of the present invention, when the thickness of each layer is in the above range, a film excellent in dimensional stability against heat and adhesion between layers in a dry state and a wet state can be obtained.

2. Production method of polyamide multilayer film The production method of the polyamide multilayer film of the present invention is not particularly specified. For example, the raw materials of each layer are melt-kneaded with an extruder set at a cylinder temperature of 180 to 290 ° C. Coextrusion is carried out on a chill roll in which cooling water circulates from a T die so as to obtain a flat multilayer film.

  The obtained film may be uniaxially stretched or biaxially stretched (simultaneous biaxial stretching and sequential biaxial stretching). The stretching ratio is, for example, longitudinal stretching (MD) 2.5 to 4.5 times and transverse stretching (TD) 2.5 to 5.0 times.

  For example, in the case of sequential biaxial stretching, longitudinal stretching is performed 2.5 to 4.5 times with a roll stretching machine at 50 to 80 ° C., and further 2.5 to 5.0 with a tenter stretching machine in an atmosphere at 50 to 150 ° C. The film can be stretched by a factor of 2 and then heat-treated in an atmosphere of 100 to 240 ° C. with the same tenter. The multilayer stretched film of the present invention may be simultaneously biaxially stretched and sequentially biaxially stretched. If necessary, the obtained multilayer stretched film can be subjected to corona discharge treatment on both surfaces or one surface.

3. Polyamide-based multilayer film of the present invention which is produced as feature above polyamide-based multilayer film has excellent adhesion between the layers in the dimensional stability and dry and wet states relative to superior thermal. Therefore, it is suitably used as a packaging film.

  The polyamide-based multilayer film of the present invention has excellent adhesion between each layer in a dry state and a wet state. The film was cut out with a width of 10 mm, stored under conditions of 23 ° C. × 65% RH under drying, and stored under water at 23 ° C. for 24 hours under wet conditions. And an interface between the (C1) layer and an interface between the (B2) layer and the (C2) layer (an interface between the polyamide-based copolymer layer and the sulfone group-containing polyester layer) at 23 ° C. × 65% RH. Then, a T-shaped peel test is performed at a speed of 200 mm / min. In this case, the peel strength (N / cm) is 1.0 N / cm or more, preferably 1.5 N / cm or more.

  Moreover, the polyamide-based multilayer film of the present invention has excellent thermal dimensional stability. MD × TD = 100 mm × 100 mm The polyamide-based multilayer film of the present invention has a heat shrinkage ratio of less than 2.0% and further less than 1.6% in the MD direction after being boiled by dipping in boiling water. In the TD direction, it is characterized by being less than 2.0% and further less than 1.6%.

  Since the polyamide-based multilayer film of the present invention has the above characteristics, it is suitably used as a packaging film. A sealing film is laminated on one side of the polyamide-based multilayer film to produce a packaging film. This is made into a bag shape with the seal layer facing inward, and the seal layer surfaces are heat-sealed and processed into a bag shape to produce a packaging bag.

  Here, the sealing layer may be a resin film having heat sealing properties. For example, LLDPE (linear low density polyethylene), LDPE (low density polyethylene), CPP (unstretched polypropylene), EVA (ethylene-ethylene-) Polyolefins such as vinyl acetate copolymer). As a method of laminating the polyamide-based multilayer film and the seal layer, a known method can be adopted. Also, a known method can be adopted as a heat sealing method.

  The obtained packaging bag is filled with the contents to obtain a package. The contents to be packaged are not particularly limited, but in particular, water-based foods such as soups, rice cakes and pickles, heavy foods such as rice cakes, winners and seasonings, shampoos for refilling, rinses, body soaps, The effect of the present invention is remarkably exerted when packaging a heavy liquid such as a detergent.

  Examples of the form of the packaging bag include bag-like forms such as a three-side seal form, an envelope form, a caseette form, and a flat bottom form, a spout pouch, a refill pouch, and the like.

  Furthermore, since the multilayer film of the present invention has high transparency, it is easy to visually check the contents when packaged.

  Next, the present invention will be described in more detail with reference to the following examples and comparative examples, but is not limited thereto.

Example 1
(A) Nylon-6 “UBE nylon-1022FDX23” (manufactured by Ube Industries Co., Ltd.), which is an aliphatic polyamide, is used as a layer, and nylon 6 / 6,6 “UBE”, which is a polyamide copolymer, is used as a (B1) layer. Nylon-5023B "(manufactured by Ube Industries, Ltd.), and sulfoisophthalic acid copolymerized polyethylene terephthalate which is a sulfone group-containing polyester as a (C1) layer" component derived from dicarboxylic acid is terephthalic acid (95 mol%) and 5 -Polyester (sodium sulfoisophthalic acid (5 mol%), a polyester derived from ethylene glycol as the component derived from diol (Intrinsic viscosity: 0.50 dl / g)) "and (D1) polyethylene terephthalate" BEL Pet EFG6C "(manufactured by Bell Polyester Products) It had.

  The resin constituting each layer is (A) layer and (B1) layer as base material layer, (C1) layer and (D1) layer as surface layer, and (D1) layer / (C1) layer / (B1) layer / (A) A flat four-layer film was obtained by co-extrusion on a chill roll through which cooling water circulates in order of the layers. This four-layer film was longitudinally stretched 2.7 times by a 65 ° C roll stretcher, then stretched 4.0 times by a tenter stretcher in an atmosphere of 110 ° C, and further in an atmosphere of 210 ° C by the same tenter. And a four-layer film having a thickness of 15 μm was obtained. The thickness of each layer is as described in Table 1.

Example 2
(A) Nylon-6 “UBE nylon-1022FDX23” (manufactured by Ube Industries Co., Ltd.), which is an aliphatic polyamide, is used as a layer, and nylon 6 / 6,6 “UBE”, which is a polyamide copolymer, is used as a (B1) layer. Nylon-5023B "(manufactured by Ube Industries, Ltd.), and sulfoisophthalic acid copolymerized polyethylene terephthalate which is a sulfone group-containing polyester as a (C1) layer" component derived from dicarboxylic acid is terephthalic acid (95 mol%) and 5 -Polyester (Intrinsic Viscosity: 0.50 dl / g) ", which is sodium sulfoisophthalic acid (5 mol%) and the component derived from diol is ethylene glycol.

  The resin constituting each layer is (C) layer / (B1) layer / (A) layer in the order of (A) layer and (B1) layer as a base material layer and (C1) layer as a surface layer. , And co-extruded on a chill roll in which cooling water circulates from a T die to obtain a flat three-layer film. This three-layer film was longitudinally stretched 2.7 times by a 65 ° C. roll stretching machine, then transversely stretched 4.2 times by a 110 ° C. atmosphere tenter stretching machine, and further in a 210 ° C. atmosphere by the same tenter. And a three-layer film having a thickness of 15 μm was obtained. The thickness of each layer is as described in Table 1.

Example 3
(A) Nylon-6 “UBE nylon-1022FDX23” (manufactured by Ube Industries Co., Ltd.), which is an aliphatic polyamide, is used as the layer, and nylon 6 /, which is a polyamide copolymer, is used as the (B1) layer and the (B2) layer. 6,6 “UBE Nylon-5023B” (manufactured by Ube Industries, Ltd.), sulfoisophthalic acid copolymerized polyethylene terephthalate which is a sulfone group-containing polyester as a (C1) layer and a (C2) layer “component derived from dicarboxylic acid” Terephthalic acid (95 mol%) and 5-sodium sulfoisophthalic acid (5 mol%), and a polyester derived from ethylene glycol as the component derived from a diol (Intrinsic viscosity: 0.50 dl / g) ", (D1) layer And (D2) polyethylene terephthalate “Belpet EFG6C” which is crystalline polyester as the layer Was used (Co., Ltd. bell polyester Products).

  Resin constituting each layer, (A) layer, (B1) layer and (B2) layer are substrate layers, (C1) layer and (D1) layer are surface layers, (C2) layer and (D2) layers are back surfaces The cooling water flows from the T dice so that the layers are in the order of (D1) layer / (C1) layer / (B1) layer / (A) layer / (B2) layer / (C2) layer / (D2) layer. It was coextruded on a circulating chill roll to obtain a flat seven-layer film. This seven-layer film was longitudinally stretched 2.7 times by a 65 ° C. roll stretcher, then transversely stretched 4.0 times by a tenter stretcher at 110 ° C. atmosphere, and further in a 210 ° C. atmosphere by the same tenter. And a seven-layer film having a thickness of 15 μm was obtained. The thickness of each layer is as described in Table 1.

Example 4
(A) Nylon-6 “UBE nylon-1022FDX23” (manufactured by Ube Industries Co., Ltd.), which is an aliphatic polyamide, is used as the layer, and nylon 6 /, which is a polyamide copolymer, is used as the (B1) layer and the (B2) layer. 6,6 “UBE Nylon-5023B” (manufactured by Ube Industries, Ltd.), sulfoisophthalic acid copolymerized polyethylene terephthalate which is a sulfone group-containing polyester as a (C1) layer and a (C2) layer “component derived from dicarboxylic acid” Terephthalic acid (95 mol%) and 5-sodium sulfoisophthalic acid (5 mol%), and a polyester derived from ethylene glycol as the component derived from a diol (Intrinsic viscosity: 0.50 dl / g) ", (D1) layer Polyethylene terephthalate "Belpet EFG6C" (Bell Corporation), which is a crystalline polyester Using Li made ester Products).

  The resin constituting each layer is made of (A) layer, (B1) layer and (B2) layer as a base material layer, (C1) layer and (D1) layer as a surface layer, and (C2) layer as a back layer, (D1 ) Layer / (C1) layer / (B1) layer / (A) layer / (B2) layer / (C2) layer are co-extruded on a chill roll through which cooling water circulates from a T die, A flat 6-layer film was obtained. This 6-layer film was longitudinally stretched 2.7 times by a 65 ° C. roll stretching machine, then transversely stretched 4.0 times by a tenter stretching machine at 110 ° C., and further in a 210 ° C. atmosphere by the same tenter. And a six-layer film having a thickness of 15 μm was obtained. The thickness of each layer is as described in Table 1.

Example 5
A four-layer film was produced in the same manner as in Example 1 except that the thickness of each layer was changed as described in Table 1.

Example 6
A 7-layer film was produced in the same manner as in Example 3 except that the thickness of each layer was changed as described in Table 1.

Comparative Example 1
(A) Nylon-6 “UBE nylon-1022FDX23” (manufactured by Ube Industries Co., Ltd.), which is an aliphatic polyamide, is used as the layer, and sulfoisophthalic acid copolymerized polyethylene terephthalate, “dicarboxylic”, which is a sulfone group-containing polyester, as the (C1) layer. Polyester (Intrinsic Viscosity: 0.50 dl / g) in which the component derived from the acid is terephthalic acid (95 mol%) and 5-sodium sulfoisophthalic acid (5 mol%) and the component derived from the diol is ethylene glycol Polyethylene terephthalate “Belpet EFG6C” (manufactured by Bell Polyester Products Co., Ltd.), which is crystalline polyester, was used as the (D1) layer.

  The resin constituting each layer is such that (A) layer is a base material layer, (C1) layer and (D1) layer are surface layers, and the order is (D1) layer / (C1) layer / (A) layer. , And co-extruded on a chill roll in which cooling water circulates from a T die to obtain a flat three-layer film. This three-layer film was longitudinally stretched 2.7 times by a 65 ° C. roll stretcher, then stretched 4.0 times by a tenter stretcher at 110 ° C. atmosphere, and further in a 210 ° C. atmosphere by the same tenter. And a three-layer film having a thickness of 15 μm was obtained. The thickness of each layer is as described in Table 1.

Comparative Example 2
(A) Nylon-6 “UBE nylon-1022FDX23” (manufactured by Ube Industries Co., Ltd.), which is an aliphatic polyamide, is used as a layer, and nylon 6 / 6,6 “UBE”, which is a polyamide copolymer, is used as a (B1) layer. Nylon-5023B "(manufactured by Ube Industries, Ltd.) was used, and polyethylene terephthalate" Belpet EFG6C "(manufactured by Bell Polyester Products), which is a crystalline polyester, was used as the (D1) layer.

  The resin constituting each layer is (A) layer and (B1) layer as a base material layer, (D1) layer as a surface layer, and the order is (D1) layer / (B1) layer / (A) layer. , And co-extruded on a chill roll in which cooling water circulates from a T die to obtain a flat three-layer film. This three-layer film was longitudinally stretched 2.7 times by a 65 ° C. roll stretcher, then stretched 4.0 times by a tenter stretcher at 110 ° C. atmosphere, and further in a 210 ° C. atmosphere by the same tenter. And a three-layer film having a thickness of 15 μm was obtained. The thickness of each layer is as described in Table 1.

Comparative Example 3
(B1) Nylon 6/6, 6 “UBE nylon-5023B” (manufactured by Ube Industries Co., Ltd.), which is a polyamide copolymer, is used as the layer, and the sulfone group-containing polyester is used as the (C1) layer and the (C2) layer. A certain sulfoisophthalic acid copolymerized polyethylene terephthalate “polyester derived from dicarboxylic acid is terephthalic acid (95 mol%) and 5-sodium sulfoisophthalic acid (5 mol%), and a component derived from diol is ethylene glycol (extreme viscosity) : 0.50 dl / g) ”, and polyethylene terephthalate“ Belpet EFG6C ”(manufactured by Bell Polyester Products Co., Ltd.), which is a crystalline polyester, was used as the (D1) layer and the (D2) layer.

  The resin constituting each layer is (B1) layer as a base material layer, (C1) layer and (D1) layer as a surface layer, (C2) layer and (D2) layer as a back layer, and (D1) layer / (C1 ) Layer / (B1) layer / (C2) layer / (D2) layer were co-extruded on a chill roll in which cooling water circulates from a T die to obtain a flat five-layer film. This 5-layer film was longitudinally stretched 2.7 times by a 65 ° C roll stretcher, then stretched 4.2 times by a tenter stretcher at 110 ° C atmosphere, and further in an atmosphere at 210 ° C by the same tenter. Was heat treated to obtain a 5-layer film having a thickness of 18 μm. The thickness of each layer is as described in Table 1.

Test Examples The following test items were measured for the polyamide-based multilayer films obtained in Examples 1 to 6 and Comparative Examples 1 to 3. The results are shown in Table 2.

[Interlaminar strength test]
It peeled at the interface of a surface layer and a base material layer, and the interface of a base material layer and a back surface layer, and cut out the film by width 10mm. A T-shaped peel test was performed at a speed of 200 mm / min under conditions of dryness (after storage for 24 hours in an atmosphere of 23 ° C. × 65% RH) and wet conditions (after storage for 24 hours in water at 23 ° C.). The results are shown in Table 2.

[Thermal dimensional stability test]
A sample of MD × TD = 100 mm × 100 mm was heat-treated, and the shrinkage rate (%) after the boil treatment was measured at 98 ° C. × 60 minutes. The results are shown in Table 2.

  It can be seen that the polyamide-based multilayer films of Examples 1 to 6 are excellent in interlayer strength under both dry and wet conditions. On the other hand, in the multilayer stretched film of Comparative Example 1 having no (B1) layer, the interlayer strength was not sufficient under wet conditions. Moreover, in the multilayer stretched film of Comparative Example 2 having no (C1) layer, the interlayer strength was not sufficient under both dry and wet conditions.

  Moreover, it turns out that the polyamide-type multilayer film of Examples 1-6 has a small thermal contraction rate, and is excellent in the dimensional stability with respect to a heat | fever. On the other hand, the comparative example 3 which does not have a (A) layer had a large heat shrinkage rate, and was not preferable. In addition, since the multilayer stretched film of the comparative example 2 which does not have a (C1) layer had peeled delamination during a boil process, it was not able to measure a thermal contraction rate.

Claims (10)

A polyamide multilayer film having at least three layers of a sulfone group-containing polyester layer (C1 layer), a polyamide copolymer layer (B1 layer) and an aliphatic polyamide layer (A layer) in this order. A polyamide-based multilayer film having at least four layers in this order: a crystalline polyester layer (D1 layer), a sulfone group-containing polyester layer (C1 layer), a polyamide copolymer layer (B1 layer), and an aliphatic polyamide layer (A layer) . Crystalline polyester layer (D1 layer), sulfone group-containing polyester layer (C1 layer), polyamide copolymer layer (B1 layer), aliphatic polyamide layer (A layer), polyamide copolymer layer (B2 layer) and A polyamide-based multilayer film having at least 6 layers of a sulfone group-containing polyester layer (C2 layer) in this order. Crystalline polyester layer (D1 layer), sulfone group-containing polyester layer (C1 layer), polyamide copolymer layer (B1 layer), aliphatic polyamide layer (A layer), polyamide copolymer layer (B2 layer), A polyamide-based multilayer film having at least 7 layers of a sulfone group-containing polyester layer (C2 layer) and a crystalline polyester layer (D2 layer) in this order. The polyamide-based multilayer film according to any one of claims 1 to 4, wherein a total thickness of the polyamide-based multilayer film is 10 to 80 µm. The total thickness of the polyamide layer ((A) layer, (B1 layer) and (B2 layer)) is 30 to 95% with respect to the total thickness of the polyamide-based multilayer film, according to any one of claims 1 to 5. Polyamide-based multilayer film. A polyamide-based multilayer film obtained by biaxially stretching the polyamide-based multilayer film according to claim 1. A packaging film obtained by laminating a seal layer on one surface of the polyamide-based multilayer film according to claim 1. The packaging bag obtained by making the packaging film of Claim 8 into a bag shape, and heat-sealing seal layer surfaces. A package formed by filling the packaging bag according to claim 9 with the contents.