JP2012011741A - Coextruded multilayer film with bad smell barrier property, packaging material using the same, and packaging container - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coextruded multilayer film with a bad smell barrier property, in which processing for preventing the change in the quality of content articles by intrusion of volatile components, etc. from the outside to packaging material of food, etc. is easy, and a packaging material using this, and a packaging container.SOLUTION: The coextruded multilayer film is made by laminating a surface resin layer (A) containing a polyolefin based resin as a main component, an adhesion resin layer (B) containing an acid denatured polyolefin as a main component, and a bad smell barrier resin layer (C) in the order of (A)/(B)/(C)/(B)/(A), wherein the resin layer (C) is a single resin or a mixture of 0 to 55 mass% of amorphous polyethylene terephthalate based polymer and 45 to 100 mass% of polybutylene terephthalate homopolymer, or a single resin or a mixture of 0 to 55 mass% of amorphous polyethylene terephthalate based polymer, and 45 to 100 mass% of specific polybutylene terephthalate based copolymer as a main component.

Description

  The present invention relates to an odor barrier coextrusion multilayer film that is easy to process for preventing deterioration of contents due to erosion of volatile components from the outside during storage of packaging materials filled with food, sundries, etc. And a packaging material and a packaging container using the same.

  Conventionally, many packaging materials for filling foods, sundries, etc. have been used in which a polyolefin resin is laminated on a paper base material. When storing food and miscellaneous goods packed in this paper container for a long time, in order to maintain the state of the contents, oxygen in the air and odor components such as insect repellents, fragrances, deodorants, etc. It is necessary to shut off.

  For example, in order to provide oxygen barrier properties, a method has been proposed in which a biaxially stretched polyvinyl alcohol film layer is further laminated using an anchor coating agent on a paper base material on which a polyolefin resin layer is laminated. (For example, refer to Patent Document 1). Although the polyvinyl alcohol resin originally has an oxygen barrier property, a certain effect can be obtained in terms of preventing oxidative deterioration of the contents. However, in the method of Patent Document 1, a biaxially stretched film is anchor-coated. Since lamination is performed using an agent, the process is complicated, and there are problems of odor and VOC generation at the production site, which is inferior in productivity.

  Further, for blocking odor components such as insect repellents, fragrances, and deodorants, a method of laminating polyester films having specific physical properties has been proposed (for example, see Patent Document 2).

  In the said patent document 2, in the point which needs to adjust the content rate of the titanium derived from the catalyst contained in the polyester to be used, versatility is low, and also in the point which requires the application | coating process of an anchor coat agent, said patent document 1 Have similar problems. In particular, when applying an adhesive to a polyester film, it is necessary to adjust even the difference in the in-plane refractive index after drying, which also has difficulty in process control, and further improvements are necessary. .

Japanese Patent Application Laid-Open No. 07-076336 JP 2005-161536 A

  The problem to be solved by the present invention is an odor that is easy to process for preventing deterioration of contents due to erosion of volatile components from the outside during storage of packaging materials filled with food and miscellaneous goods. The object is to provide a barrier coextrusion multilayer film, and a packaging material and packaging container using the same.

  As a result of intensive studies to solve the above problems, the present inventors have found that the above problems can be solved by using a coextruded multilayer film using a specific polyester resin mixture in the odor barrier resin layer. The present invention has been completed.

  That is, the present invention includes a surface resin layer (A) mainly composed of a polyolefin-based resin (a1), an adhesive resin layer (B) mainly composed of an acid-modified polyolefin (b1), and an odor barrier resin layer ( C) is a coextruded multilayer film laminated in the order of (A) / (B) / (C) / (B) / (A), and the odor barrier resin layer (C) is amorphous. A mixture or a single resin of a crystalline polyethylene terephthalate polymer (c1) 0 to 55% by mass and a polybutylene terephthalate homopolymer (c2) 45 to 100% by mass, or an amorphous polyethylene terephthalate polymer (c1) 0 to 55 Mixture or single tree of mass% and 45-100 mass% of polybutylene terephthalate copolymer (c3) obtained using terephthalic acid and isophthalic acid as dicarboxylic acid components , An odor barrier co-extruded multilayer film, a packaging material obtained by extruding and laminating this to other sheet-like substrates, and box making and bag making A packaging container is provided.

  The odor barrier co-extruded multilayer film of the present invention has these odors for packaging materials used in containers stored in a place close to those having volatile chemical components such as insect repellents, deodorants, and fragrances. The performance of blocking can be imparted, the permeation of the component can be blocked, and the contents can be prevented from being altered or deteriorated. In addition, since the surface layer of the multilayer film is composed of a polyolefin resin layer, there is no need to apply an anchor coating agent or the like as long as the substrate is coated with a polyolefin resin and a heat-sealable resin layer. It is possible to stack by an easy method such as the above, there is no occurrence of VOC and the like, the production process can be simplified, and the application range is wide.

  Hereinafter, the present invention will be described in detail. In the multilayer film of the present invention, the surface resin layer (A), the adhesive resin layer (B), and the odor barrier resin layer (C) are (A) / (B) / (C) / (B) / ( A coextruded multilayer film laminated in the order of A). In the present application, “main component” means that the mass ratio of the specific resin or resin mixture to the total mass of each layer is 65 mass% or more, preferably 80 mass% or more.

  The surface resin layer (A) of the coextruded multilayer film of the present invention has a polyolefin resin (a1) as its main component. As the polyolefin resin (a1), the adhesive resin layer (B) and the resin or resin mixture used for the odor barrier resin layer (C), which will be described later, can be easily co-extruded, and the resulting multilayer film can be simply laminated such as by extrusion lamination. It is preferable to use a polyethylene resin or a polypropylene resin alone or in admixture because they can be easily laminated to other substrates by the technique.

  Examples of the polyethylene resin include low density polyethylene, linear low density polyethylene, medium density polyethylene, and high density polyethylene. These may be used alone or in combination.

  In addition, these polyethylene resins preferably have an MFR (190 ° C.) of 0.5 to 30.0 g / 10 minutes because of easy extrusion, and more preferably an MFR of 2.0 to 15 0.0 g / 10 min. Furthermore, if these polyethylene resins have a melting point of 80 to 135 ° C., the shrinkage of the film during lamination hardly occurs, and the packaging suitability is improved. More preferably, the melting point is 90 to 130 ° C.

  Examples of the polypropylene resin include a propylene homopolymer, a propylene-ethylene copolymer, a propylene-butene-1 copolymer, a propylene-ethylene-butene-1 copolymer, and a metallocene catalyst-based polypropylene. These may be used alone or in combination. When these polypropylene resins are used as the resin layer (A), the heat resistance of the film is improved and the processing strength at the time of lamination can be increased. I can do it.

  These polypropylene resins preferably have an MFR (230 ° C.) of 0.5 to 30.0 g / 10 min and a melting point of 120 to 165 ° C., more preferably an MFR (230 ° C.) of 2 0 to 15.0 g / 10 min, and the melting point is 125 to 162 ° C. When the MFR and the melting point are in this range, the film formability is good.

  In the multilayer film of the present invention, the surface resin layer (A) is both the front surface and the back surface, each using the same resin or resin mixture, and different resins or resin mixtures on the front surface and the back surface. It may be used.

  It is essential that the adhesive resin layer (B) of the coextruded multilayer film of the present invention is mainly composed of the acid-modified polyolefin (b1).

  The acid-modified polyolefin (b1) is obtained by graft copolymerizing an unsaturated carboxylic acid such as maleic anhydride or a derivative thereof with a polyolefin resin. Examples of the polyolefin resin include the polyethylene resins and the polypropylene resins mentioned as the polyolefin resin (a1) used for the surface resin layer (A). Moreover, the copolymer of ethylene, methyl (meth) acrylate, vinyl acetate, etc. may be sufficient.

  In addition, a tackifier, a reaction catalyst, etc. may be added to the adhesive resin layer (B) in order to increase the interlayer adhesive strength between the surface resin layer (A) and the odor barrier resin layer (C) described later. Examples of the tackifier include resins having an adhesive property at room temperature composed of natural resins and synthetic resins. For example, natural resin rosin, polymerized rosin, hydrogenated rosin, glycerinster rosin, pentaerythritol, and other rosin resins. Terpenes such as terpenes, aromatic terpenes, terpene phenols, hydrogenated terpenes; aliphatic petroleum resins, aromatic petroleum resins, hydrogen alicyclic petroleum resins; polybutadienes that are liquid at room temperature; polyisoprenes that are liquid at room temperature And polyisobutylene which is liquid at room temperature.

  Resins used for the odor barrier resin layer (C) of the coextruded multilayer film of the present invention are amorphous polyethylene terephthalate polymer (c1) 0 to 55% by mass and polybutylene terephthalate homopolymer (c2) 45 to 100% by mass. Or a single resin, or a polybutylene terephthalate copolymer (c3) obtained by using 0 to 55% by mass of an amorphous polyethylene terephthalate polymer (c1) and terephthalic acid and isophthalic acid as dicarboxylic acid components ) The main component is a mixture of 45 to 100% by mass or a single resin.

  The amorphous polyethylene terephthalate polymer (c1) is a polyester resin composed of a dicarboxylic acid component mainly composed of terephthalic acid and a glycol component mainly composed of ethylene glycol. In this polyethylene terephthalate polymer, as a copolymerization component, a part of dicarboxylic acid is isophthalic acid, 2,6-naphthalenedicarboxylic acid, hexahydroterephthalic acid, hydroxybenzoic acid, diphenyl ether dicarboxylic acid, adipic acid, sebacic acid, etc. The thing used 1 type, or 2 or more types is mentioned. In addition, as part of the glycol component, 1,4-cyclohexanedimethanol, diethylene glycol, hexamethylene glycol, trimethylene glycol, tetramethylene glycol, polyalkylene glycol, for example, one or two of polyethylene glycol, polytetramethylene glycol, etc. The thing using the above is mentioned. Trifunctional or higher functional compounds such as glycerin, pentaerythritol, trimellitic acid and the like may be used in such a degree that the polymer is substantially linear.

  The amorphous polyethylene terephthalate polymer (c1) used in the present invention preferably has an intrinsic viscosity of 0.7 dl / g or more. If it is lower than 0.7 dl / g, the fluidity is difficult to match at the merged portion when coextruded with the (A) layer and the (B) layer, and this may cause flow unevenness on the film surface and cause poor appearance.

  Examples of such commercially available amorphous polyethylene terephthalate polymer (c1) include PETG manufactured by Eastman Chemical Co., Ltd., which is a copolymer of polyethylene terephthalate and 1,4-cyclohexanedimethanol.

  The term “amorphous” in the present application means that it does not have a peak of 0.5 J / g or more in the range of 23 ° C. to 300 ° C. in DSC (differential scanning calorimetry).

  The polybutylene terephthalate homopolymer (c2) is a polyester synthesized by polycondensation of terephthalic acid and 1,4-butanediol. The polybutylene terephthalate homopolymer (c2) preferably has an intrinsic viscosity of 0.7 dl / g or more. If it is lower than 0.7 dl / g, the fluidity may be difficult to match at the merged portion when coextruded with the (A) layer and the (B) layer, which may cause poor appearance of the film surface.

  Examples of such a commercially available polybutylene terephthalate homopolymer (c2) include NOVADURAN 5020 (homopolybutylene terephthalate resin, intrinsic viscosity 1.20 dl / g) manufactured by Mitsubishi Engineering Plastics, or DURANEX manufactured by Wintech Polymer Co., Ltd. 500FP (homopolybutylene terephthalate resin, intrinsic viscosity 0.875 dl / g) and the like.

  The polybutylene terephthalate copolymer (c3) obtained by using terephthalic acid and isophthalic acid as the dicarboxylic acid component is a polymer of a dicarboxylic acid component mainly composed of terephthalic acid and 1,4-butanediol. In addition, isophthalic acid is copolymerized as the third component. Its intrinsic viscosity is preferably 0.7 dl / g or more. If it is lower than 0.7 dl / g, the fluidity may be difficult to match at the merged portion when coextruded with the (A) layer and the (B) layer, which may cause poor appearance of the film surface.

  The polybutylene terephthalate copolymer (c3) preferably has a melting point of 170 ° C. or higher or a glass transition point of 25 ° C. or higher.

  As a commercial item of the polybutylene terephthalate copolymer (c3) obtained by using the terephthalic acid and isophthalic acid, for example, DURANEX 400LP (inherent viscosity: 0.765 melting point: 170 ° C.) manufactured by Wintech Polymer Co., Ltd. Glass transition point: 27 ° C.).

In the present invention, the odor barrier resin layer (C) is
(1) A mixture of the amorphous polyethylene terephthalate polymer (c1) 0 to 55% by mass and the polybutylene terephthalate homopolymer (c2) 45 to 100% by mass or a single resin (2) Amorphous polyethylene terephthalate heavy Mixture (c1) 0-55 mass% and polybutylene terephthalate copolymer (c3) 45-100 mass% obtained by using terephthalic acid and isophthalic acid as a dicarboxylic acid component, or a single resin as a main component It is what.

  When the proportion of the amorphous polyethylene terephthalate polymer (c1) used exceeds 55% by mass, the resulting multilayer film is inferior in odor barrier properties, and thus is put to practical use as an odor barrier multilayer film. More preferable mixing ratio is 40 to 55% by mass of the amorphous polyethylene terephthalate polymer (c1), polybutylene terephthalate homopolymer (c2) or polybutylene terephthalate obtained using terephthalic acid and isophthalic acid as the dicarboxylic acid component. The copolymer (c3) is 45 to 60% by mass.

  The odor barrier co-extruded multilayer film of the present invention preferably has a total film thickness of 15 to 150 μm, particularly preferably 30 to 60 μm from the viewpoint of easy handling. If the thickness of all the films is in this range, the film can be easily formed, and the handleability is good. From the viewpoint of odor barrier properties, the thickness of the barrier resin layer (C) is preferably 1 to 75 μm, particularly preferably in the range of 5 to 25 μm, and 5 to 50 for the total film thickness. % Is preferable.

  The method for producing the odor barrier coextrusion multilayer film of the present invention is not particularly limited as long as it is a coextrusion lamination method. For example, a resin or a resin mixture used for each resin layer using a plurality of extruders And a method of processing into a film using a method such as inflation or a T-die chill roll method after laminating and laminating in a molten state by a co-extrusion method such as a multi-manifold die method or a feed block method. In the case of the T-die / chill roll method, the melt-laminated film may be nipped and cooled between a rubber touch roll, a steel belt or the like and the chill roll.

  Furthermore, the odor barrier coextrusion multilayer film of the present invention may be stretched in at least a uniaxial direction. As the stretching method, various methods such as longitudinal or lateral uniaxial stretching, sequential biaxial stretching, simultaneous biaxial stretching, or tubular method biaxial stretching can be employed. Further, the stretching process may be inline or offline. The stretching method for uniaxial stretching may be a proximity roll stretching method or a rolling method. The stretching ratio of uniaxial stretching is preferably 1.1 to 80 times, more preferably 3 to 30 times in the longitudinal or transverse direction. On the other hand, the stretch ratio of biaxial stretching is preferably 1.2 to 70 times in terms of area ratio, more preferably 4 to 6 times in length, 5 to 9 times in width, and 20 to 54 times in area ratio.

  The odor barrier coextrusion multilayer film of the present invention includes any one of the surface resin layer (A), the adhesive resin layer (B), the odor barrier resin layer (C), or two or more resin layers, and other heat. You may add a plastic resin, a heat stabilizer, an antistatic agent, an antiblocking agent, a slip agent, etc. in the range which does not impair the objective of this invention.

  The odor barrier packaging material of the present invention is obtained by laminating the above-mentioned odor barrier coextruded multilayer film (I) on another substrate. In particular, the sheet-like substrate (II) whose surface is coated with a resin layer containing a polyolefin-based resin is preferable because it can be easily laminated by an extrusion lamination method.

  Specifically, a polyolefin resin layer is laminated on a paper substrate from the viewpoint that the adhesive strength with the odor barrier co-extruded multilayer film of the present invention can be easily prepared and the characteristics of the present application can be sufficiently exhibited. It is preferable to use a sheet-like substrate.

  The odor barrier co-extruded multilayer film of the present invention obtained in this way, and the odor barrier packaging material laminated with the odor barrier co-extruded multilayer film are not particularly specified for their use. For example, various foods It can be suitably used as a packaging bag for food and miscellaneous goods, or a packaging container for food and miscellaneous goods. Especially, it is preferable that it is made into a packaging container by making a box or making a bag so that the odor barrier co-extruded multilayer film (I) side of the odor barrier packaging material is on the inside. It can be suitably used as a container for instant noodles to be stored.

  The present invention will be specifically described below with reference to examples and comparative examples.

The film performance was evaluated as follows.
(1) Evaluation of odor barrier property The obtained film was cut out into two 7 cm squares and overlapped, using three sides with a precision heat sealer (manufactured by Tester Sangyo), at a temperature of 140 ° C., a pressure of 0.2 MPa, and a width of 10 mm. A bag was made by heat sealing with a seal bar for 1.0 second. Into this bag, 0.1 g of p-dichlorobenzene was put and the upper part of the bag was similarly heat-sealed so that the content area was 5 cm × 5 cm. Put this sachet into a 100 ml mayonnaise bottle, cap it so that it does not leak, leave it in a constant temperature room at 23 ° C. and 50% RH, and wait until you feel the odor of p-dichlorobenzene in the mayonnaise bottle the following day. It was confirmed.

(2) Evaluation of the number of steps The following number of steps was counted for the steps until the laminate for box making was completed.
2-1. Manufacture of paper 2-2. PE extrusion 2-3. Printing 2-4. Anchor coat 2-5. Film deposition

Example 1
As the surface resin layer (A), linear low density polyethylene (density 0.93 g / cm 3, melt flow rate 6 g / 10 min; hereinafter referred to as LLDPE) is used, and the amount of acid modification is 2.9 mass as the adhesive resin layer (B). %, An acid-modified ethylene-propylene-butene copolymer (hereinafter referred to as an adhesive resin) having a density of 0.89 g / cm 3, and a polybutylene terephthalate copolymer (Wintech) as the odor barrier resin layer (C). DURANEX 400LP manufactured by Polymer Co., Ltd., hereinafter referred to as PBT copolymer], an extruder for surface resin layer (A) (caliber 50 mm), an extruder for adhesive resin layer (B) (caliber 40 mm), and odor barrier properties Resin is supplied to each of the resin layer (C) extruders (caliber 40 mm), and from the T die at an extrusion temperature of 230 ° C. by coextrusion method (A) / (B) / (C) / B) Extruded so that the thickness of the layer (A) is 10 μm / 5 μm / 20 μm / 5 μm / 10 μm, cooled with a water-cooled metal cooling roll at 30 ° C., wound on a roll, and in a aging room at 35 ° C. for 48 hours. By aging, a coextruded multilayer film of the present invention having a total thickness of 50 μm was obtained.

Example 2
The coextruded multilayer film of Example 2 was used in the same manner as in Example 1 except that polybutylene terephthalate (Dulanex 500FP manufactured by Wintech Polymer Co., Ltd .; hereinafter referred to as PBT) was used as the odor barrier resin layer (C). Obtained.

Example 3
The odor barrier resin layer (C) was used except that a mixture of 45 parts by mass of a PBT copolymer and 55 parts by mass of an amorphous polyethylene terephthalate copolymer (Easman Chemical PETG6763; hereinafter referred to as PETG) was used. The coextruded multilayer film of Example 3 was obtained in the same manner as Example 1.

Example 4
A coextruded multilayer film of Example 4 was obtained in the same manner as in Example 1 except that a mixture of 60 parts by mass of PBT copolymer and 40 parts by mass of PETG was used as the odor barrier resin layer (C).

Example 5
A coextruded multilayer film of Example 5 was obtained in the same manner as in Example 1 except that a mixture of 45 parts by mass of PBT and 55 parts by mass of PETG was used as the odor barrier resin layer (C).

Example 6
A coextruded multilayer film of Example 6 was obtained in the same manner as in Example 1 except that a mixture of 60 parts by mass of PBT and 40 parts by mass of PETG was used as the odor barrier resin layer (C).

Example 7
As the odor barrier resin layer (C), a mixture of 45 parts by mass of PBT and 55 parts by mass of PETG was used, and the thickness of the (A) / (B) / (C) / (B) / (A) layer was 15 μm / A coextruded multilayer film of Example 7 was obtained in the same manner as in Example 1 except that the film was extruded to 5 μm / 10 μm / 5 μm / 15 μm.

Example 8
As the odor barrier resin layer (C), a mixture of 45 parts by mass of PBT copolymer and 55 parts by mass of PETG was used, and the thickness of the (A) / (B) / (C) / (B) / (A) layer A co-extruded multilayer film of Example 8 was obtained in the same manner as in Example 1 except that the film was extruded so as to be 15 μm / 5 μm / 10 μm / 5 μm / 15 μm.

Comparative Example 1
A biaxially stretched polyester film with a film thickness of 12 μm and a polyethylene film with a film thickness of 30 μm were laminated using a urethane adhesive to obtain a laminate film.

Comparative Example 2
A polyethylene film having a thickness of 50 μm was used as a film having no barrier layer.

Claims (8)

A surface resin layer (A) mainly composed of a polyolefin-based resin (a1), an adhesive resin layer (B) mainly composed of an acid-modified polyolefin (b1), and an odor barrier resin layer (C) (A ) / (B) / (C) / (B) / (A), a co-extruded multilayer film,
The odor barrier resin layer (C)
A mixture or a single resin of amorphous polyethylene terephthalate polymer (c1) 0 to 55% by mass and polybutylene terephthalate homopolymer (c2) 45 to 100% by mass, or amorphous polyethylene terephthalate polymer (c1) 0 The main component is a mixture or a single resin of ˜55 mass% and 45 to 100 mass% of a polybutylene terephthalate copolymer (c3) obtained by using terephthalic acid and isophthalic acid as a dicarboxylic acid component. An odor barrier co-extruded multilayer film characterized by being. The odor barrier co-extruded multilayer film according to claim 1, wherein the polyolefin resin (a1) is a polyethylene resin or a polypropylene resin. The odor barrier co-extruded multilayer film according to claim 1 or 2, wherein the acid-modified polyolefin (b1) is a maleic anhydride-modified polyolefin. The total thickness of the odor barrier co-extruded multilayer film is 15 to 150 µm, and the thickness of the odor barrier resin layer (C) is 5 to 50% of the total thickness. The odor barrier co-extruded multilayer film described. The odor barrier co-extruded multilayer film (I) according to any one of claims 1 to 4 is extrusion laminated to a sheet-like substrate (II) whose surface is coated with a resin layer containing a polyolefin resin. Odor barrier packaging material characterized by being obtained by the following. The odor barrier packaging material according to claim 5, wherein the sheet-like substrate (II) is formed by laminating a polyolefin resin layer on a paper substrate. An odor barrier packaging container, wherein the odor barrier co-extruded multilayer film (I) side of the odor barrier packaging material obtained in claim 5 or 6 is boxed or bag-made. The odor barrier packaging container according to claim 7, which is used for food.