JP5388515B2 - Multi-layer laminate with excellent interlayer strength - Google Patents

Description

  The present invention relates to a multilayer laminate having excellent interlayer strength used as various packaging materials.

  Conventional attempts to provide functional films by laminating polyamide resins with gas barrier properties, toughness, pinhole resistance, etc., and polyester resins with excellent mechanical, optical, thermal properties, etc. Has been made.

  However, since the polyamide-based resin and the polyester-based resin have insufficient adhesiveness, there is a problem that the interlayer strength is low when both are laminated.

  In order to solve this problem, for example, in Patent Document 1, a film made of a polyamide copolymer having a melting point of 150 ° C. or lower is laminated on at least one surface of a polyethylene terephthalate film via an adhesive resin such as a modified polyolefin resin. A three-layer film has been reported.

  Patent Document 2 describes a multilayer container in which an adhesive layer made of a sulfonic acid-containing polyester is provided between a polyester resin layer containing polyethylene terephthalate and a polyamide resin layer.

Patent Document 3 is a laminated film in which five or more polyester resin layers and polyamide resin layers are alternately laminated, and the polyester resin layer and / or the polyamide resin layer contains a compatibilizing agent such as a polyesteramide compound, A polyester resin and / or a polyamide resin having a metal-sulfoisophthalic acid residue is described.
JP 58-175658 A Japanese Unexamined Patent Publication No. 63-40 JP 2004-58294 A

  An object of this invention is to provide the multilayer laminated body excellent in the interlayer intensity | strength of a polyester-type resin layer and a polyamide-type resin layer.

  As a result of earnest research to solve the above problems, the present inventor is a multilayer laminate in which a polyester resin layer and a polyamide resin layer are laminated, and the polyester resin layer contains a sulfone group. It has been found that a multilayer laminate comprising polyester and having a polyamide-based resin layer containing a resin obtained by copolymerizing an aliphatic polyamide resin and an unsaturated carboxylic acid or a derivative thereof has excellent interlayer strength. Based on this knowledge, the present invention was completed by further research.

  That is, the present invention provides the following multilayer laminate.

  Item 1. A multilayer laminate in which a polyester resin layer and a polyamide resin layer are laminated, wherein the polyester resin layer contains a sulfone group-containing polyester, and the polyamide resin layer comprises an aliphatic polyamide resin and an unsaturated carboxylic acid or A multilayer laminate comprising a resin in which the derivative is copolymerized.

  Item 2. Item 2. The multilayer laminate according to Item 1, wherein the sulfone group-containing polyester is a copolymer containing sodium sulfoisophthalic acid and / or sodium sulfoterephthalic acid units as part of an acid component.

Item 3. The sulfone group-containing polyester contains sodium sulfoisophthalic acid and / or sodium sulfoterephthalic acid unit as a part of the acid component in an amount of 0.5 to 10 mol% based on the total acid component.
Item 2. The multilayer laminate according to Item 1, which is a copolymer containing the multilayer laminate.

Item 4. Item 1, 2 wherein the sulfone group-containing polyester has an intrinsic viscosity of 0.3 to 0.8 dl / g
Or the multilayer laminated body of 3.

  Item 5. The resin in which the unsaturated carboxylic acid or derivative thereof is copolymerized is at least selected from the group consisting of modified polyolefin, ethylene-methacrylic acid ionomer, ethylene-acrylic acid ester-maleic anhydride and ethylene-acrylic acid ester-glycidyl methacrylate. Item 5. The multilayer laminate according to any one of Items 1 to 4, which is one type.

  Item 6. Item 6. The multilayer laminate according to any one of Items 1 to 5, wherein the content of the unsaturated carboxylic acid or derivative thereof in the polyamide-based resin layer is 0.1 to 15% by weight.

  Item 7. The aliphatic polyamide resin is 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), polyhexa Methylene sebacamide (nylon-6,10), polyhexamethylene dodecamide (nylon-6,12), polyoctamethylene adipamide (nylon-8,6), polydecamethylene adipamide (nylon-10, 8) Caprolactam / lauryl lactam copolymer (nylon-6 / 12), caprolactam / ω-a Nonanoic acid copolymer (nylon-6 / 9), caprolactam / hexamethylene diammonium adipate copolymer (nylon-6 / 6,6), lauryl lactam / hexamethylene diammonium adipate copolymer (nylon-12 / 6) 6), ethylenediamine adipamide / hexamethylene diammonium adipate copolymer (nylon-2,6 / 6,6), caprolactam / hexamethylene diammonium adipate / hexamethylene diammonium sebacate copolymer (nylon-6) , 6/6, 10), and at least one selected from the group consisting of ethyleneammonium adipate / hexamethylenediammonium adipate / hexamethylenediammonium sebacate copolymer (nylon-6 / 6, 6/6, 10) 1-6 which are Multi-layer laminate according to any one.

  Item 8. The multilayer laminate according to any one of Items 1 to 7, wherein the polyester resin layer (A) and the polyamide resin layer (B) are laminated in the order of A / B or A / B / A. A multilayer laminate.

Item 9. The multilayer laminate according to any one of Items 1 to 7, wherein the polyester resin layer (A), the polyamide resin layer (B), the barrier layer (C), and the polyester layer (D) are
A / B / C / B / A,
D / A / B,
D / A / B / A,
D / A / B / A / D,
D / A / B / C / B / A,
Or D / A / B / C / B / A / D,
A multilayer laminate that is laminated in this order.

  Item 10. The multilayer laminate according to claim 9, wherein the barrier layer (C) contains an ethylene-vinyl alcohol copolymer (EVOH) and / or an aromatic polyamide.

  Item 11. Item 10. The multilayer laminate according to Item 9, wherein the polyester layer contains polyethylene terephthalate.

  Item 12. Item 12. The multilayer laminate according to any one of Items 1 to 11, obtained by biaxially stretching 2.5 to 4.5 times in the longitudinal direction and 2.5 to 5 times in the transverse direction.

  Item 13. Item 12. The multilayer laminate according to any one of Items 1 to 11, wherein the total thickness of the multilayer film is 10 to 50 μm.

  Item 14. 14. A packaging film obtained by laminating a seal layer on one surface of the multilayer laminate according to any one of items 1 to 13.

  Item 15. A packaging film obtained by laminating a seal layer on the surface of a polyester resin layer containing a sulfone group-containing polyester of the multilayer laminate according to Item 1.

  Item 16. Item 16. A packaging bag obtained by making the packaging film according to Item 14 or 15 into a bag shape and heat-sealing the sealing layer surfaces.

  Item 17. Item 17. A package comprising the packaging bag according to Item 16 filled with contents.

  Item 18. A method for producing a multilayer laminate in which a polyester resin layer and a polyamide resin layer are laminated, comprising a resin for a polyester resin layer containing a sulfone group-containing polyester, an aliphatic polyamide resin and an unsaturated carboxylic acid or a derivative thereof And a polyamide-based resin layer resin containing a resin copolymerized by coextrusion, stretching in two directions in the vertical and horizontal directions, and heat-treating.

  The multilayer laminate of the present invention is excellent in interlayer strength between the polyester resin layer and the polyamide resin layer. Therefore, it is suitable for packaging heavy objects, particularly packaging heavy liquids such as shampoos, rinses, body soaps and detergents for refilling.

The present invention is described in detail below.
I. Multilayer laminate The multilayer laminate of the present invention is a multilayer laminate obtained by laminating a polyester resin layer and a polyamide resin layer, the polyester resin layer containing a sulfone group-containing polyester, and the polyamide resin layer Includes a resin obtained by copolymerizing an aliphatic polyamide resin and an unsaturated carboxylic acid or a derivative thereof. Thereby, the adhesive strength between the polyester resin layer and the polyamide resin layer is dramatically improved.

Polyester resin layer (A)
The polyester constituting the polyester resin layer is a sulfone group-containing polyester.

  The sulfone group-containing polyester is a copolymer containing sodium sulfoisophthalic acid and / or sodium sulfoterephthalic acid units as part of an acid component in the polyester. A specific example is one in which part of the acid component of PET is replaced with 5-sodium sulfoisophthalic acid.

  The copolymerization ratio of sodium sulfoisophthalic acid and / or sodium sulfoterephthalic acid in the sulfone group-containing polyester is 0.5 to 10 mol%, preferably 3 to 5 mol%, based on the total acid component. The intrinsic viscosity is 0.3 to 0.8 dl / g, preferably 0.4 to 0.7 dl / g. The sulfone group-containing polyester is commercially available or can be easily produced by those skilled in the art.

  The above-mentioned sulfone group-containing polyester can be selected according to its application, and may be used alone or as a mixture of two or more.

  The polyester-based resin layer may contain another resin that is compatible with the sulfone group-containing polyester as necessary, as long as the effects of the present invention are not adversely affected. Examples of the other resin include polyethylene terephthalate (PET), polyethylene terephthalate / isophthalate, and polybutylene terephthalate. However, the content of other resins is preferably less than 70% by weight, more preferably less than 50% by weight, and particularly preferably less than 20% by weight with respect to the weight of the polyester resin layer, from the viewpoint of adhesive strength.

  Since the polyester resin layer is usually an outer layer, it may contain a lubricant as required. The lubricant is not particularly limited as long as it can reduce the dynamic friction coefficient on the surface of the polyester layer as the outer layer, and examples thereof include inorganic filler particles, bisamide compounds, and mixtures thereof.

  In addition, in this invention, you may have two or more polyester-type resin layers, and the kind and compounding ratio of polyester may be the same or different in that case. Usually, from the viewpoint of simplicity of production of the multilayer laminate, it is preferable to use polyesters of the same type and the same blending ratio.

Polyamide resin layer (B)
The resin constituting the polyamide resin layer includes a resin obtained by copolymerizing a polyamide resin and an unsaturated carboxylic acid or a derivative thereof.

  The polyamide resin preferably contains an aliphatic polyamide resin as a main component, and may contain other polyamide components as necessary.

  Examples of the aliphatic polyamide resin include aliphatic nylon and copolymers thereof. Specifically, polycapramide (nylon-6), poly-ω-aminoheptanoic acid (nylon-7), poly-ω-aminononanoic acid (nylon-9), polyundecanamide (nylon-11), polylauryllactam ( Nylon-12), polyethylenediamine adipamide (nylon-2,6), polytetramethylene adipamide (nylon-4,6), polyhexamethylene adipamide (nylon-6,6), polyhexamethylene Bacamide (nylon-6,10), polyhexamethylene dodecamide (nylon-6,12), polyoctamethylene adipamide (nylon-8,6), polydecamethylene adipamide (nylon-10,8) , Caprolactam / lauryl lactam copolymer (nylon-6 / 12), caprolactam / ω-aminononanoic acid copolymer Body (nylon-6 / 9), caprolactam / hexamethylenediammonium adipate copolymer (nylon-6 / 6,6), lauryllactam / hexamethylenediammonium adipate copolymer (nylon-12 / 6,6), Ethylenediamine adipamide / hexamethylenediammonium adipate copolymer (nylon-2,6 / 6,6), caprolactam / hexamethylenediammonium adipate / hexamethylenediammonium sebacate copolymer (nylon-6,6 / 6) 10), ethyleneammonium adipate / hexamethylene diammonium adipate / hexamethylene diammonium sebacate copolymer (nylon-6 / 6, 6/6, 10), etc., among which two or more fats Can be mixed with polyamid polyamide .

  Preferred aliphatic polyamide resins include nylon-6, nylon-6,6, nylon-6 / 6,6 (copolymer of nylon 6 and nylon 6,6), more preferably nylon-6, nylon. -6/6, 6 and particularly preferably nylon-6. As the two or more kinds of aliphatic polyamides, a combination of nylon-6 and nylon-6 / 6,6 (weight ratio of about 50:50 to 95: 5) is preferable.

  Examples of other polyamide components include aromatic polyamides. As the aromatic polyamide, for example, an aromatic diamine such as metaxylenediamine and paraxylenediamine and a dicarboxylic acid such as adipic acid, suberic acid, sebacic acid, cyclohexanedicarboxylic acid, terephthalic acid, and isophthalic acid, or a derivative thereof can be used. Examples thereof include crystalline aromatic polyamides obtained by a condensation reaction. 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, an amorphous aromatic polyamide (amorphous nylon) obtained by a polycondensation reaction between an aliphatic diamine such as hexamethylenediamine and a dicarboxylic acid such as terephthalic acid or isophthalic acid or a derivative thereof can be used. Preferred is a copolymer of hexamethylene diamine-terephthalic acid-hexamethylene diamine-isophthalic acid. Specific examples include Sealer PA (Mitsui / DuPont Polychemical Co., Ltd.).

  The polyamide resin preferably contains an aliphatic polyamide resin (particularly nylon-6) as a main component, and the polyamide resin contains about 60 to 100% by weight, preferably 80 to 100% by weight of the aliphatic polyamide resin. About% is contained. The polyamide resin contains about 0 to 40% by weight, preferably about 0 to 20% by weight of aromatic polyamide.

  Examples of the resin in which the unsaturated carboxylic acid or its derivative is copolymerized include modified polyolefin, ethylene-methacrylic acid ionomer, ethylene-acrylic acid ester-maleic anhydride, and ethylene-acrylic acid ester-glycidyl methacrylate.

  Examples of the modified polyolefin include a modified polymer obtained by copolymerizing a polyolefin with an unsaturated carboxylic acid or a derivative thereof (for example, graft copolymerization). Examples of the polyolefin include olefin homopolymers, mutual copolymers, and copolymers with other copolymerizable monomers (for example, other vinyl monomers). Specific examples include polyethylene (LDPE, LLDPE, etc.), polypropylene, polybutene, their intercopolymers, ionomer resins, ethylene-acrylic acid copolymers, ethylene-vinyl acetate copolymers, and the like. As unsaturated carboxylic acid or its derivative (s), unsaturated carboxylic acid, such as maleic acid and fumaric acid, its acid anhydride, its ester, or its metal salt etc. can be illustrated, for example. Among these, as the modified polyolefin, maleic acid-modified polyolefin is preferable.

  Specifically, maleic anhydride-modified polyolefin resin (for example, Mitsui Chemicals, Inc. Admer SF730, SF731, SF740, SE800; Modic AP912T, etc.) is exemplified.

  Examples of the ethylene-methacrylic acid ionomer include those produced by crosslinking an acrylic polymer and ethylene with a metal ion such as sodium or zinc. Specifically, for example, Mitsui-DuPont Polychemical Co., Ltd. High Milan 1557 is exemplified.

  Examples of ethylene-acrylic acid ester-maleic anhydride include terpolymers of ethylene, acrylic acid, and maleic anhydride. Specifically, for example, Arkema Corp. Bondine AX8390, Bondine LX4110 and the like are exemplified.

  Examples of the ethylene-acrylic acid ester-glycidyl methacrylate include a copolymer of ethylene, acrylic acid ester, and glycidyl methacrylate. Specifically, for example, Arkema Co., Ltd. Rotader AX8840, Rotader AX8900 and the like are exemplified.

  The content of the resin in which the unsaturated carboxylic acid or derivative thereof is copolymerized is 0.1 to 15% by weight, preferably 0.5 to 10% by weight, more preferably 1 to 5% by weight in the polyamide resin layer. If it is this range, since the adhesiveness with a polyester-type resin containing a sulfone group containing polyester will improve markedly if it is this range, the interlayer intensity | strength of a polyamide-type resin layer and a polyester-type resin layer will improve dramatically. .

Barrier layer (C)
The multilayer laminate may further include a barrier layer in addition to the polyester resin layer and the polyamide resin layer. The barrier layer is usually provided in the inner layer of the laminate. Examples of the resin constituting the barrier layer include ethylene-vinyl alcohol copolymer (EVOH) and aromatic polyamide. By including this barrier layer, the gas barrier properties are dramatically improved.

  EVOH is not particularly limited, but has an ethylene content of 55 mol% or less (preferably 20 to 50 mol%, more preferably 29 to 44 mol%) and a saponification degree of vinyl acetate component of 90 mol% or more (preferably 95 mol% or more) is preferably used.

  EVOH includes a small amount of an α-olefin such as propylene, isobutene, α-octene, α-dodecene, α-octadecene, etc .; an unsaturated carboxylic acid or a derivative thereof (in the range not adversely affecting the effects of the present invention). For example, it may contain a comonomer such as a salt, a partial alkyl ester, a complete alkyl ester, a nitrile, an amide, an anhydride); an unsaturated sulfonic acid or a salt thereof.

  The melt index (MI) of EVOH is preferably 0.5 to 50 g / 10 min (210 ° C., 2160 g load), more preferably 1 to 35 g / 10 min (same as above). If the MI is 0.5 g / 10 min (same as above) or higher, the melt extrusion is not hindered. On the other hand, if the MI is 50 g / 10 min (same as above) or less, the deterioration of the film forming property is suppressed. it can.

  Examples of preferable EVOH include SG464B, DC3203FB, DT2903B (all manufactured by Nippon Synthetic Chemical Co., Ltd.) and the like.

  Examples of aromatic polyamides include polycondensation of aromatic diamines such as metaxylenediamine and paraxylenediamine with dicarboxylic acids such as adipic acid, suberic acid, sebacic acid, cyclohexanedicarboxylic acid, terephthalic acid, and isophthalic acid, or derivatives thereof. Examples thereof include crystalline aromatic polyamides obtained by the reaction. An aromatic nylon such as polymetaxylene adipamide (MXD-nylon) is preferable. Examples of the aromatic nylon include S-6007 and S-6011 (both manufactured by Mitsubishi Gas Chemical Co., Ltd.).

  The barrier layer may further contain other components such as an aliphatic amide, a modified ethylene vinyl acetate copolymer, and a methacrylic acid copolymer ionomer as long as the effects of the present invention are not adversely affected. When the barrier layer contains other components, the content of these components is usually 15 parts by weight or less, preferably about 1.0 to 7.5 parts by weight, based on 100 parts by weight of EVOH or aromatic polyamide.

Polyester layer (D)
In addition to the polyester resin layer and the polyamide resin layer, the multilayer laminate may further include a polyester layer. The polyester layer is usually provided on the outer layer from the viewpoint of heat resistance, dimensional stability, and aroma retention. Examples of the polyester layer include polyethylene terephthalate (PET) and polyethylene terephthalate / isophthalate.

  The polyester layer may contain other resins, but its content is less than 50% by weight, and less than 30% by weight, based on the weight of the polyester layer, in terms of heat resistance, dimensional stability, and transparency. It is preferable that

Multilayer laminate The multilayer laminate of the present invention has a polyester resin layer containing a sulfone group-containing polyester and a polyamide resin layer containing a resin obtained by copolymerizing an aliphatic polyamide resin and an unsaturated carboxylic acid or a derivative thereof. .

  The shape of the multilayer laminate of the present invention is not particularly limited, but is usually a film shape. The total thickness of the film is, for example, 10 to 50 μm, preferably 10 to 30 μm, although it depends on the number of layers.

  For example, in the case of a laminate comprising a polyester resin layer (A) and a polyamide resin layer (B), for example, a multilayer laminate obtained by laminating in the order of A / B or A / B / A can be mentioned.

  In addition to the polyester resin layer (A) and the polyamide resin layer (B), a barrier layer (C) may be provided. As a laminated body containing these, the 5 layer laminated body laminated | stacked in order of A / B / C / B / A is mentioned, for example.

  Furthermore, a polyester layer (D) may be provided on at least one surface of the multilayer laminate. As a laminated body containing these, for example, D / A / B, D / A / B / A, D / A / B / A / D, D / A / B / C / B / A, or D / A A multilayer laminate formed by laminating in the order of / B / C / B / A / D.

  The thickness of the polyester resin layer (A) is, for example, 0.5 to 30 μm, preferably 0.5 to 20 μm.

  The thickness of the polyamide resin layer (B) is, for example, 1 to 49.5 μm, or preferably 1 to 29.5 μm.

  The thickness of the barrier layer (C) is, for example, 0.5 to 20 μm, preferably 0.5 to 15 μm.

  The thickness of the polyester layer (D) is, for example, 0.5-48.5 μm, preferably 0.5-28.5 μm.

  In the case of two layers (A / B), the thickness of each layer is as follows: polyester resin layer (0.5-30 μm) / polyamide resin layer (1-49.5 μm), preferably polyester resin layer (1-20 μm) / polyamide It is a system resin layer (4 to 29 μm).

  In the case of three layers (A / B / A), the thickness of each layer is as follows: polyester resin layer (0.5-29.5 μm) / polyamide resin layer (1-49.5 μm) / polyester resin layer (0.5-29.5 μm), The polyester resin layer (0.5 to 19.5 μm) / polyamide resin layer (4 to 29 μm) / polyester resin layer (0.5 to 19.5 μm) is preferable.

  In the case of 5 layers (A / B / C / B / A), the thickness of each layer is as follows: polyester resin layer (0.5-29.5 μm) / polyamide resin layer (1-49 μm) / barrier layer (0.5-20 μm) / Polyamide resin layer (1 to 49 μm) / Polyester resin layer (0.5 to 29.5 μm), preferably Polyester resin layer (0.5 to 19.5 μm) / Polyamide resin layer (1 to 27.5 μm) / Barrier layer (0.5 To 15 μm) / polyamide resin layer (1 to 27.5 μm) / polyester resin layer (0.5 to 19.5 μm).

In the multilayer laminate of the present invention, the interlaminar strength of the polyester-based resin layer (A) and the polyamide-based resin layer (B) is extremely high, and the toughness, gas barrier properties, and dimensional stability are achieved by setting the thickness of each layer within the above range. Film having excellent properties, incense retention, moisture resistance and pinhole resistance can be obtained.
II. Production method of multilayer laminate The multilayer laminate of the present invention comprises the above-mentioned polyester-based resin layer (A) and polyamide-based resin layer (B), and optionally, a resin for each layer of a barrier layer (C) and a polyester layer (D). Can be manufactured by coextrusion, stretching in two longitudinal and transverse directions, and heat treatment.

  For example, a flat multilayer film is obtained by co-extrusion on a chill roll in which cooling water circulates from a T die so as to be in the order of each layer. The obtained film was longitudinally stretched 2.5 to 4.5 times by a roll stretching machine at 50 to 100 ° C., for example, and further stretched to 2.5 to 5 times by a tenter stretching machine in an atmosphere at 90 to 150 ° C., and then the same tenter. Can be obtained by heat treatment in an atmosphere of 100 to 240 ° C.

  The multilayer film of the present invention may be uniaxially stretched or biaxially stretched (simultaneous biaxial stretching, sequential biaxial stretching), and the obtained multilayer stretched film may be subjected to a corona discharge treatment on both surfaces or one surface if necessary. Can also be applied.

  The multilayer laminate of the present invention has excellent interlayer strength. A film is cut out with a width of 10 mm, and a T-shaped peel test is performed at a speed of 200 mm / min under the condition of 23 ° C. × 65% RH at the interface between the polyester resin layer and the polyamide resin layer. In this case, the interlayer strength (N / cm) is 2.0 N / cm or more, preferably 2.5 N / cm or more.

  Furthermore, the multilayer laminate of the present invention has excellent toughness, gas barrier properties, dimensional stability, aroma retention, moisture resistance and more pinhole resistance. Therefore, it is suitably used as a packaging film.

  Since the multilayer laminate of the present invention has the above characteristics, it is suitably used as a packaging film. A sealing film is laminated on one surface of the multilayer laminate to produce a packaging film. This is formed into a bag shape with the outermost layer facing outward, and the sealing 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, and examples thereof include polyolefins such as LLDPE, LDPE, CPP, and EVA. A known method can be adopted as a method of laminating the multilayer laminate and the seal layer. 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 exhibited when packaging a heavy liquid such as a detergent.

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

  Furthermore, since the multilayer laminate 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.
[Interlaminar strength test]
A film having a width of 10 mm was cut out from the obtained laminated film and peeled at the interface between the polyester resin layer and the polyamide resin layer. Specifically, a T-shaped peel test was performed at a speed of 200 mm / min under the condition of 23 ° C. × 65% RH. The results of the interlayer strength (unit: N / cm) are shown in Tables 1 and 2.

Example 1
For the first and third layers, polyethylene terephthalate (intrinsic viscosity: 0.55 dl / g) obtained by copolymerizing 3 mol% of sodium sulfoisophthalic acid with respect to the acid content in the polyester was used, and polyamide resin nylon was used as the second layer. A resin in which 99 parts by weight of -6 “UBE nylon-1022FDX23” (manufactured by Ube Industries) and 1 part by weight of modified polyolefin “Modic AP 912T” (manufactured by Mitsubishi Chemical Corporation) was blended was used.

  The resin constituting each layer was coextruded on a chill roll in which cooling water circulates from a T die so that the order of the first layer / second layer / third layer was obtained, and a flat three-layer film was obtained. . 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. To obtain a three-layer film having a thickness of 20 μm. The thickness of each layer was 5/10/5 (μm).

Examples 2-17
A three-layer film was produced in the same manner as in Example 1 except that the resin composition and the blending amount of each layer were changed as described in Table 1. The thickness of each layer was set to 5/10/5 (μm) as in Example 1.

Comparative Examples 1-10
A three-layer film was produced in the same manner as in Example 1 except that the resin composition and the blending amount of each layer were changed as described in Table 1. The thickness of each layer was set to 5/10/5 (μm) as in Example 1.

  It turns out that the multilayer film of Examples 1-17 is excellent in interlayer strength. On the other hand, it was confirmed that the multilayer films of Comparative Examples 1 to 10 have a significant decrease in interlayer strength.

Nylon 6: Polycapramide (nylon-6) “UBE nylon-1022FDX23”, manufactured by Ube Industries, Ltd. Nylon 6-66: A copolymer of nylon 6 and nylon 66 “UBE nylon-5034B”, manufactured by Ube Industries, Ltd. MXD6 : Polymetaxylene adipamide (MXD-nylon) “MX Nylon S6011”, manufactured by Mitsubishi Gas Chemical Co., Ltd. SIPE3-PET: Polyethylene terephthalate copolymerized with 3 mol% sodium sulfoisophthalic acid SIPE5-PET: Sodium sulfoisophthalate Polyethylene terephthalate copolymerized with 5 mol% of acid SIPE8-PET: Polyethylene terephthalate copolymerized with 8 mol% of sodium sulfoisophthalic acid PET: Polyethylene terephthalate “Velpet EFG6C”, manufactured by Bell Polyester Products Co., Ltd.
Example 18
In accordance with the description in Example 1, a multilayer film having a four-layer structure: PET / SIPE3-PET / nylon 6 + modified polyolefin / SIPE3-PET was produced. The thickness of each layer was 2/2/9/2 (μm).

Example 19
In accordance with the description in Example 1, a multilayer film having a 6-layer structure: PET / SIPE3-PET / nylon 6 + modified polyolefin / EVOH / nylon 6 + modified polyolefin / SIPE3-PET was produced. The film thickness of each layer was 2/2/3/3/3/2 (μm).

Example 20
According to the description in Example 1, a multilayer film having a 6-layer structure: PET / SIPE3-PET / nylon 6 + modified polyolefin / MXDNY / nylon 6 + modified polyolefin / SIPE3-PET was produced. The film thickness of each layer was 2/2/3/3/3/2 (μm).

  The multilayer films obtained in Examples 18 to 20 all had excellent interlayer strength.

Claims (16)

A multilayer laminate comprising a polyester resin layer (A), a polyamide resin layer (B), a barrier layer (C) if necessary, and a polyester layer (D) if necessary , wherein the polyester resin wherein the layer (a) is a sulfonic group-containing polyester, the polyamide-based resin layer (B) is an aliphatic polyamide resin and an unsaturated carboxylic acid or its derivative is copolymerized resins seen including,
A / B,
A / B / A,
A / B / C / B / A,
D / A / B,
D / A / B / A,
D / A / B / A / D,
D / A / B / C / B / A, or
D / A / B / C / B / A / D,
A multilayer laminate that is laminated in this order . The multilayer laminate according to claim 1, wherein the sulfone group-containing polyester is a copolymer containing sodium sulfoisophthalic acid and / or sodium sulfoterephthalic acid units as part of an acid component. The said sulfone group containing polyester is a copolymer which contains 0.5-10 mol% of sodium sulfoisophthalic acid and / or a sodium sulfoterephthalic acid unit in a part of acid component with respect to all the acid components. Multilayer laminate. The multilayer laminate according to claim 1, wherein the sulfone group-containing polyester has an intrinsic viscosity of 0.3 to 0.8 dl / g. The resin obtained by copolymerizing the unsaturated carboxylic acid or its derivative is a modified polyolefin, an ethylene-methacrylic acid ionomer, an ethylene-acrylic acid ester-maleic anhydride copolymer and an ethylene-acrylic acid ester-glycidyl methacrylate copolymer. It is at least 1 sort (s) chosen from the group which consists of coalescence , The multilayer laminated body in any one of Claims 1-4. The multilayer laminate according to any one of claims 1 to 5, wherein the content of the unsaturated carboxylic acid or derivative thereof in the polyamide-based resin layer (B) is 0.1 to 15% by weight. The aliphatic polyamide resin is 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), polyhexa Methylene sebacamide (nylon-6,10), polyhexamethylene dodecamide (nylon-6,12), polyoctamethylene adipamide (nylon-8,6), polydecamethylene adipamide (nylon-10, 8) Caprolactam / lauryl lactam copolymer (nylon-6 / 12), caprolactam / ω-a Nonanoic acid copolymer (nylon-6 / 9), caprolactam / hexamethylene diammonium adipate copolymer (nylon-6 / 6,6), lauryl lactam / hexamethylene diammonium adipate copolymer (nylon-12 / 6) 6), ethylenediamine adipamide / hexamethylene diammonium adipate copolymer (nylon-2,6 / 6,6), caprolactam / hexamethylene diammonium adipate / hexamethylene diammonium sebacate copolymer (nylon-6) , 6/6, 10), and at least one selected from the group consisting of ethyleneammonium adipate / hexamethylenediammonium adipate / hexamethylenediammonium sebacate copolymer (nylon-6 / 6, 6/6, 10) Claim 1 Multilayer laminate according to any one of 6. The multilayer laminate according to any one of claims 1 to 7, wherein the barrier layer (C) contains an ethylene-vinyl alcohol copolymer (EVOH) and / or an aromatic polyamide. The multilayer laminate according to any one of claims 1 to 8, wherein the polyester layer (D) contains polyethylene terephthalate. The multilayer laminate according to any one of claims 1 to 9, which is obtained by biaxially stretching 2.5 to 4.5 times in the longitudinal direction and 2.5 to 5 times in the transverse direction. The multilayer laminate according to any one of claims 1 to 10 , wherein a total thickness of the multilayer laminate is 10 to 50 µm. Packaging film obtained by laminating on one surface of the multilayer stack, the sealing layer according to any one of the claims 1 to 11. The packaging film formed by laminating | stacking a sealing layer on the surface of the polyester-type resin layer (A) containing the sulfone group containing polyester of the multilayer laminated body in any one of the said Claims 1-11 . The packaging bag obtained by making the packaging film of the said Claim 12 or 13 into a bag shape, and heat-sealing seal layer surfaces. A package formed by filling the packaging bag according to claim 14 with contents. A method for producing the multilayer laminate according to claim 1 , wherein the polyester resin layer (A), the polyamide resin layer (B), a barrier layer (C) as necessary, and a polyester as necessary. A production method comprising laminating a resin for each layer of the layer (D) by coextrusion, stretching the resin vertically and horizontally, and subjecting it to a heat treatment.