JP2019162760A - Heat-sealable multilayer film, and medical package - Google Patents

Abstract

To provide a heat-sealable multilayer film which is excellent in transparency and strength and is also excellent in slipperiness, and a medical package using the heat-sealable multilayer film.SOLUTION: A heat-sealable multilayer film has at least one heat seal layer on a surface layer and at least one layer containing a polyamide-based resin, and has a layer containing a polyolefin-based resin adjacent to the heat seal layer, in which the heat seal layer is a layer containing a resin composition of an ethylene-methyl acrylate copolymer (A) and unsaturated fatty acid amide (B).SELECTED DRAWING: None

Description

  The present invention relates to a heat-sealable multilayer film and a medical packaging body using the film.

  In recent years, deep-drawn packages and four-sided bags made of plastic films have been widely used as medical packages and food packages. In recent years, there are many requests for universal design of packaging bodies due to global environmental problems, declining birthrate and aging problems, etc., and many functions are required for the packaging bodies.

  In addition to container transparency related to the visibility of contents, strengths such as hygiene and pinhole resistance are also required depending on applications. In particular, as a package that can be opened more easily, it is required to provide easy peelability (easy opening), and an easy peelable film has been studied by the compounding design of the resin used for the heat seal layer. Yes. (Patent Document 1)

JP 2014-162162 A

  However, since the conventional easy peel film has almost no slipperiness, the sealant layer and the base material layer of the multilayer sheet are adhered in the film forming process, slit process, bag making process, contents filling process, etc. A so-called blocking phenomenon occurs, and there is a problem that bag-making workability and filling workability are remarkably lowered.

  An object of the present invention is to provide a heat-sealable multilayer film that is excellent in transparency and strength and excellent in slipperiness, and a medical packaging body using the sheet-sealable multilayer film.

As a result of intensive studies to solve the above problems, the present inventor has found that the problem can be solved by the following means.
The first aspect of the present invention is a heat having at least one heat seal layer on the surface layer, at least one layer containing a polyamide resin, and a layer containing a polyolefin resin adjacent to the heat seal layer. A heat-sealable multilayer film, wherein the heat-seal layer is a layer containing a resin composition of an ethylene-methyl acrylate copolymer (A) and an unsaturated fatty acid amide (B). .

  In the first present invention, the unsaturated fatty acid amide (B) constituting the unsaturated fatty acid amide (B) preferably has 18 to 22 carbon atoms, and the unsaturated fatty acid amide has a melting point of 65 ° C. or higher. .

  In the first aspect of the present invention, the coefficient of dynamic friction between the heat seal layer and the polyethylene film is preferably 0.5 or less when measured according to JIS K7125.

  In the first aspect of the present invention, the heat seal layer preferably has an easy peel property.

  The second aspect of the present invention is a medical package characterized in that the heat seal layer of the heat-sealable multilayer film of the first aspect of the present invention and a polyethylene non-woven fabric are heat sealed.

  ADVANTAGE OF THE INVENTION According to this invention, while being excellent in transparency and intensity | strength, the heat-sealable multilayer film excellent in slipperiness | lubricant and the medical packaging body using this sheet sealable multilayer film can be provided.

  Hereinafter, an embodiment of the present invention will be described in detail. In addition, this invention is not limited at all by the following embodiment.

  In the present embodiment, the “main component” means that the content of each component is preferably 50% by mass or more, more preferably 80%, based on the total resin component constituting each layer (100% by mass). More than 95% by mass, more preferably 95% by mass or more, particularly preferably 100% by mass.

  In the following embodiments, when expressed as “X to Y” (X and Y are arbitrary numbers), unless otherwise specified, “X or more and Y or less” means “preferably larger than X”. And “preferably smaller than Y”. Further, in the following embodiments, when expressed as “X or more” (X is an arbitrary number), the meaning of “preferably greater than X” is included unless otherwise specified, and “Y or less” (Y Unless otherwise specified, it is intended to include “preferably smaller than Y”.

<Heat-sealable multilayer film>
The heat-sealable multilayer film of the present invention has at least one heat-seal layer on the surface layer, at least one layer containing a polyamide-based resin, and a layer containing a polyolefin-based resin adjacent to the heat-seal layer. Have

(Heat seal layer)
The heat seal layer imparts flexibility and heat sealability to the multilayer film of the present invention, and contains a polyolefin resin that is a heat seal resin. Examples of the polyolefin resin include a polyethylene resin, a polypropylene resin, and a cyclic polyolefin resin. From the viewpoint of sheet breakability, it is preferable to use a polyolefin resin having a tensile elongation of 300% or more.

  Polyethylene resins include low density polyethylene, linear low density polyethylene, high density polyethylene, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, ethylene-acrylic acid copolymer, ethylene-acrylic acid. Examples include methyl copolymers, ethylene-methyl methacrylate copolymers, ethylene ionomers, and mixtures thereof. Examples of the polypropylene resin include homopolypropylene, random copolymers of propylene and α-olefin, and block copolymers. Examples of the cyclic polyolefin resin include a resin having a norbornene skeleton.

  These resins can be used alone or in combination. In the mixed composition, for example, a low-density polyethylene having a good sheet-forming property and a high-density polyethylene having a good sheet tearing property are mixed to adjust both physical properties, or two resins having different melting points or non-phases with each other. Soluble polyethylene and polypropylene can be mixed to give an easy peel property to the heat seal layer.

  The thickness of the heat seal layer is preferably 0.5 μm or more, more preferably 1 μm or more, and even more preferably 1.5 μm or more from the viewpoint of heat sealability, rigidity, and moldability. Moreover, it is preferable that it is 30 micrometers or less, It is more preferable that it is 27.5 micrometers or less, It is still more preferable that it is 25 micrometers or less.

The thickness ratio of the heat seal layer to the thickness of the polyamide resin layer is preferably 5% or more, more preferably 6% or more from the viewpoint of heat sealability, rigidity and moldability. Preferably, it is 7% or more, more preferably 50% or less, preferably 47.5% or less, and more preferably 45% or less.
Moreover, as a heat seal layer, a single layer may be sufficient and a multilayer may be sufficient.

  The heat-sealable multilayer film of the present invention preferably has a dynamic friction coefficient with a polyethylene film of 0.5 or less when measured according to JIS K7125. When the dynamic friction coefficient is 0.5 or less, the heat sealing of the heat-sealable multilayer film of the present invention in the molding process, slit process, bag making process, contents filling process, etc. of the heat-sealable multilayer film of the present invention. Since the layer is less likely to adhere or block, workability in each step is improved, which is preferable.

(Easy peel layer)
In the case of a multilayer heat seal layer, for example, a polyolefin resin layer mainly composed of a polyolefin resin and a polyolefin resin layer (hereinafter referred to as “EP layer”) having an easy peel (hereinafter also referred to as “EP”) function. ")". In addition, when setting it as a multilayer of EP layer and the heat seal layer which does not have EP function, it is preferable to locate EP layer in the outermost layer (namely, the side heat-sealed with a nonwoven fabric).

  Further, the main component resin of the EP layer has a melting point of usually 120 ° C. or lower, preferably 100 ° C. or lower, more preferably 75 to 85 ° C., and a condition of 190 ° C. and 21.18 N load according to JIS K7210. The melt flow rate (MFR) measured in (1) is usually within the range of 0.1 g / 10 min to 10 g / min, preferably 1 g / 10 min to 10 g / 10 min, more preferably 2 g / 10 min to 5 g / 10 min. By selecting, the degree of welding and the degree of impregnation at the time of heat sealing with polyethylene non-woven fabric at a temperature of 135 ° C or less on the packaging machine are appropriately controlled, and stable and appropriate easy peel within the above-mentioned sealing temperature range High strength, production efficiency and handling during film production, less troubles such as blocking during molding and transport in packaging machines There is improved.

  The thickness of the EP layer is preferably 2 μm or more, more preferably 3 μm or more, further preferably 4 μm or more, more preferably 20 μm or less, and even more preferably 15 μm or less. More preferably, it is 12 μm or less. If the EP layer has a thickness of 2 μm or more, stable film-forming properties can be obtained. Moreover, if thickness is 20 micrometers or less, it can make it difficult to generate | occur | produce a fuzz and a film | membrane residue at the time of peeling, and a favorable peeling external appearance is obtained.

  In the present invention, the heat seal layer is preferably a layer containing a resin composition of an ethylene-methyl acrylate copolymer (A) and an unsaturated fatty acid amide (B) from the viewpoint of having an EP function. The heat seal layer preferably contains the resin composition as a main component.

(A) Ethylene-methyl acrylate copolymer In the present invention, the heat seal layer is mainly composed of ethylene-α-olefin copolymer, ethylene-vinyl acetate copolymer (EVA), ethylene-acrylic acid copolymer. Copolymer (EAA), ethylene-ethyl acrylate copolymer (EEA), ethylene-methacrylic acid copolymer (EMAA), ethylene-methyl methacrylate copolymer (EMMA), ethylene-methyl acrylate copolymer (EMA And at least one resin composition selected from the group consisting of these ionomers. In particular, it is preferable to use an ethylene-methyl acrylate copolymer (EMA) from the viewpoints of seal strength and film formability.

  Typical examples of the ethylene-methyl acrylate copolymer (A) preferably used in the present invention include “Lex Pearl” manufactured by Nippon Polyethylene Co., Ltd. and “Elvalloy” manufactured by Mitsui DuPont Polychemical Co., Ltd. It can be mentioned as a commercially available one.

  In addition, by using two types of EMA having different melting points (high melting point EMA and low melting point EMA) in combination, adjustment of the sealing temperature with the nonwoven fabric and easy peel property (appearance after peeling) can be improved. This is preferable because it is possible. The high melting point EMA preferably has a melting point of 85 ° C. or higher and 120 ° C. or lower, more preferably 90 ° C. or higher and 100 ° C. or lower. The low melting point EMA preferably has a melting point of 60 ° C. or higher and lower than 85 ° C., more preferably 65 ° C. or higher and 80 ° C. or lower. The mixing ratio is preferably 50 to 90% by mass, and more preferably 55 to 80% by mass of EMA having a high melting point, with the total being 100% by mass.

(B) Unsaturated fatty acid amide Unsaturated fatty acid amide-based lubricants can be preferably used in order to make the heat seal layer of the multilayer film fused or difficult to block. Unsaturated fatty acid amide-based lubricants have a double bond in the molecular structure, so the molecular structure tends to bend and the molecules are less likely to adhere to each other. Therefore, since it is more dispersible than a saturated fatty acid amide-based lubricant, it has a high effect of transparency and lubricity, and therefore can be preferably used. Specific examples include unsaturated fatty acid amides and unsaturated fatty acid bisamides. Among these, unsaturated fatty acid amides having an unsaturated fatty acid amide constituting the unsaturated fatty acid amide having 18 to 22 carbon atoms and a melting point of 65 ° C. or higher are more preferable.

  As specific examples, oleic acid amide, erucic acid amide, ethylenebisoleic acid amide and the like can be used. Moreover, it is preferable to use an unsaturated fatty acid amide having an unsaturated fatty acid having 18 to 22 carbon atoms because it is excellent in the initial slip property and the effect of improving the slip property at a high temperature of 45 ° C. or higher. Moreover, it is preferable to use an unsaturated fatty acid amide having a melting point of 65 ° C. or higher because blocking resistance is improved. One type of these unsaturated fatty acid amides may be used, or two or more types may be used in combination.

  The compounding quantity of unsaturated fatty acid amide used for the multilayer film of this invention is 0.001 mass part or more and 1 mass part or less with respect to 100 mass parts of ethylene-methyl acrylate copolymers (A). Preferably, it is 0.01 mass part or more and 0.7 mass part or less, More preferably, it is 0.03 mass part or more and 0.5 mass part or less. When the blending amount is 0.001 part by mass or more, wrinkles do not occur at the winding part at the time of film formation, and winding becomes good, and when it is 1 weight or less, transparency and heat after aging Good sealing performance.

(Layer containing polyamide resin)
A layer containing a polyamide-based resin can impart flexibility and strength to the multilayer film of the present invention. It is preferable that the layer containing a polyamide resin has a polyamide resin as a main component. The multilayer film of the present invention includes at least one layer containing a polyamide-based resin (hereinafter also referred to as “PA layer”).

  The polyamide-based resin is not particularly limited, but specific examples include, for example, 4 nylon, 6 nylon, 7 nylon, 11 nylon, 12 nylon, 46 nylon, 66 nylon, 69 nylon, 610 nylon, 611 nylon, and 6T nylon. , 6I nylon, MXD6 nylon, 6-66 nylon, 6-610 nylon, 6-611 nylon, 6-12 nylon, 6-612 nylon, 6-6T nylon, 6-6I nylon, 6-66-610 nylon, 6 -66-12 nylon, 6-66-612 nylon, 66-6T nylon, 66-6I nylon, 6T-6I nylon, 66-6T-6I nylon and the like.

  Among these, as the polyamide-based resin, 6 nylon or 6-66 nylon is preferably used from the viewpoint of pinhole resistance. Two or more PA layers can be provided, and in this case, each layer may be formed of different types of polyamide-based resins.

  The thickness of the PA layer is not particularly limited, but is preferably 10% or more, more preferably 15% or more of the film layer thickness. Moreover, 70% or less is preferable and 60% or less is more preferable. By setting the thickness of the PA layer to 10% or more, sufficient pinhole resistance can be imparted to the film, and by setting the thickness to 70% or less, curling of the seal portion can be prevented.

  Representative examples of polyamides preferably used in the present invention include “Novamid” manufactured by Mitsubishi Engineering Plastics Co., Ltd., which can be obtained commercially.

(Layer containing polyolefin resin)
The layer adjacent to the heat seal layer on the surface layer of the multilayer film of the present invention is provided with a layer containing a polyolefin resin for the purpose of imparting flexibility and transparency. The layer containing a polyolefin resin preferably contains a polyolefin resin as a main component. For the polyolefin resin layer adjacent to the heat seal layer, for example, a resin similar to the polyethylene resin of the heat seal layer or an ethylene-vinyl acetate copolymer (EVA) can be used.
Moreover, propylene-type resin, such as a homopolypropylene and a propylene-alpha-olefin copolymer, can be used for a polyolefin-type resin layer. Examples of the α-olefin include ethylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene and the like.

(Other layers)
In addition, from the viewpoint of imparting appropriate moisture resistance and rigidity to the film, it is desirable to provide a layer containing a polypropylene resin (PP). The layer containing PP preferably contains PP as a main component.
Moreover, it is desirable to arrange | position the layer containing a polyethylene-type resin (PE) from a viewpoint which provides moderate softness | flexibility. Moreover, it is preferable that the layer containing PE has PE as a main component.

  Further, from the viewpoint of imparting oxygen barrier properties, it is desirable to dispose a layer containing a saponified ethylene-vinyl acetate copolymer (EVOH) in a layer other than the front and back layers. Further, the layer containing EVOH preferably contains EVOH as a main component.

  Further, an adhesive resin (AD) layer may be formed between the respective layers. As the adhesive resin, for example, a polyolefin resin modified with an unsaturated carboxylic acid or a derivative thereof can be used.

(Layer structure of multilayer film)
As a preferred layer structure, the following example can be given when the description of the adhesive resin layer is omitted and written in the order of back layer / intermediate layer / heat seal layer (surface layer). In addition, a back surface layer means the layer which exists in the opposite side of a heat seal layer in a multilayer film. The intermediate layer is a layer existing between the outer layer and the heat seal layer. In particular, the layer constitutions (1) and (3) are useful from the viewpoint of film strength, deep drawing suitability, and production cost. Note that the specific resin description in the composition of the layer means the layer to include, and the layer to include means that the resin is preferably a main component.

(1) PA / PO / heat seal,
(2) PA / EVOH / PO / heat seal,
(3) {PE or PP} / PA / PO / heat seal,
(4) {PE or PP} / PA / EVOH / PO / heat seal,
(5) {PE or PP} / EVOH / PA / PO / heat seal,

<Method for producing heat-sealable multilayer film>
The heat-sealable multilayer film of the present invention is obtained by co-extrusion using an extruder equipped with a die by an existing method such as a T-die method or a tubular method, so that the EP layer, the PA layer, and the polyolefin resin layer of the surface layer Can be manufactured at the same time. The multilayer film can also be produced sequentially using a pressing method, a roll nip method, a dry laminating method or the like after separately forming the resins constituting each layer into a sheet. Non-stretched film formation is desirable from the viewpoint of processability such as moldability. In addition, the non-stretching here means that stretching in a specific direction (winding direction or width direction) is not substantially performed, and a predetermined stretching as a force majeure for convenience of film formation is partially performed. It is meant to be included.

  Each layer may contain various additives such as an inorganic filler, an organic filler, an antioxidant, a weathering stabilizer, a light-resistant stabilizer, a lubricant, a nucleating agent, or a pigment as long as each characteristic is not impaired. Good.

<Medical packaging>
The medical packaging body of the present invention can be manufactured by cutting the heat-sealable multilayer film of the present invention into a predetermined shape, processing it into the shape of the bottom material, and then heat-sealing with the lid material. It is preferable to use a non-woven fabric made of polyethylene.
Examples of the nonwoven fabric bonded to the heat-sealable multilayer film of the present invention include sterilized paper, a microporous film made of a synthetic resin, and a nonwoven fabric made of a thermoplastic resin. Moreover, it can use suitably for joining with the nonwoven fabric of 20-100 g / m < ² > of fabric weights. In addition, these may be a single layer or a multi-layer structure of a plurality of types. In particular, the effects of the film of the present invention can be utilized when using sterilized paper for medical packaging materials. Examples of commercially available products include DuPont Tyvek, Oji Special Medica J, Asahi Kasei Kogyo Ben Rize, etc. Can be mentioned.
The conditions for heat sealing are not particularly limited, and the conditions for heat sealing with a conventional nonwoven fabric can be employed.

Hereinafter, although an Example is shown, this invention is not limited to this.
Each layer resin shown below was co-extruded at a resin temperature of 230 ° C. by a T-die method using a single screw extruder, and then rapidly cooled with a 50 ° C. cast roll to form an unstretched heat-sealing property with a total thickness of 110 μm. A multilayer film was obtained and used for the bottom material.
The layer structure is as follows.
PP (10 μm) / AD (9 μm) / Ny6 (25 μm) / AD (18 μm) / LLDPE (38 μm) / Heat seal layer (10 μm)
The heat seal layer was blended with 60% by mass of a high melting point ethylene-methyl acrylate copolymer (melting point 90 ° C.) and 40% by mass of a low melting point ethylene-methyl acrylate copolymer (melting point 77 ° C.). . In addition, sterile paper (manufactured by Oji Specialty Paper, Medica J) was used as a lid.

(Example 1)
Ethylene bisoleic acid equivalent to 0.3% by mass when the mixture of the high melting point ethylene-methyl acrylate copolymer and the low melting point ethylene-methyl acrylate copolymer is 100% by mass in the heat seal layer The multilayer film was prepared by mixing amide (melting point: 117 ° C.) and evaluated.

(Example 2)
Example 1 with the exception that the constituent resin of the heat seal layer was only a high melting point ethylene-methyl acrylate copolymer (melting point 90 ° C.) and 100% by mass of the high melting point ethylene-methyl acrylate copolymer. A heat-sealable multilayer film was produced by the same method and evaluated.

(Example 3)
A heat-sealable multilayer film was prepared and evaluated in the same manner as in Example 1 except that the unsaturated fatty acid amide compound mixed in the heat seal layer was replaced with erucic acid amide (melting point: 81 ° C.).

(Comparative Example 1)
A heat-sealable multilayer film was produced and evaluated in the same manner as in Example 1 except that the unsaturated fatty acid amide compound was not blended in the heat-seal layer.

(Comparative Example 2)
A heat-sealable multilayer film was prepared in the same manner as in Example 1 except that stearamide (melting point: 101 ° C.), which is a saturated fatty acid amide, was mixed in the heat seal layer instead of the unsaturated fatty acid amide. Evaluation was performed.

(Comparative Example 3)
A heat-sealable multilayer film is produced in the same manner as in Example 1 except that ethylene bis-stearic acid amide (melting point: 145 ° C.), which is a saturated fatty acid bisamide, is mixed in the heat-seal layer instead of the unsaturated fatty acid amide. And evaluated.

(Comparative Example 4)
A heat-sealable multilayer film was prepared and evaluated in the same manner as in Example 1 except that ethylene bislauric acid amide (melting point: 157 ° C.), which is a saturated fatty acid bisamide, was mixed with the heat seal layer.

  The following evaluation was performed about the obtained heat-sealable multilayer film. Table 1 shows the types and evaluation results of fatty acid amide lubricants blended in the film.

(1) Heat-seal property Each heat-sealable multilayer film and lid material are 150 ° C., 3 kg / cm ² , seal width 6 mm, seal time 2 seconds with a heat sealer (TP-701-B) manufactured by Tester Sangyo Co., Ltd. Heat sealed under conditions. The heat-sealed sample was cut on a strip having a width of 15 mm, peeled at a peeling rate of 100 mm / min in a 180 ° peel test, measured for peel strength, and evaluated according to the following criteria.
○: Peel strength 100 gf / 15 mm width or more,
X: Peel strength less than 100 gf / 15 mm width,

(2) Easy peel
About each heat-sealed sample, the sterilized paper was peeled from the film by manual peeling, the peeling state in that case was observed visually, and the following references | standards evaluated.
○: The sterilized paper is not torn, and no pieces of paper or fluff remain on the peeled part.
Δ: The sterilized paper cannot be torn, but some pieces of paper and fluff remain in the peeling part.
X: The sterilized paper is torn and a piece of paper or fluff remains in the peeled portion or cannot be peeled off.

(3) Sliding property In order to evaluate the sliding property of each heat-sealable multilayer film on the heat-seal layer side, the dynamic friction coefficient with a polyethylene film (LLDPE, 70 μm) was measured according to JIS K7125, and the following criteria It was evaluated with.
○: Dynamic friction coefficient 0.5 or less,
×: Dynamic friction coefficient exceeds 0.5,

(4) Film forming property The film winding property with a winder was evaluated according to the following criteria during film formation.
○: The film was wound up without any problem.
X: Films were blocked and troubles such as winding slip occurred.

(5) Transparency For each sample, a single-layer film having a thickness of 100 μm was collected only by blending the heat seal layer. About the film, the total haze was measured according to JISK7361, 7136 with the Nippon Denshoku Industries Co., Ltd. haze meter (model: NDH5000), and the following reference | standard evaluated.
○: Total haze less than 9.0%,
X: Total haze 9.0% or more,

From Table 1, since the heat-sealable multilayer film of Examples 1 to 3 of the present invention contains the ethylene-methyl acrylate copolymer (A) and the unsaturated fatty acid amide (B) in the heat seal layer. It can be seen that both slipperiness and film-forming property are good. Further, Example 1 and Example 3 use two kinds of mixtures of a high melting point ethylene-methyl acrylate copolymer and a low melting point ethylene-methyl acrylate copolymer in the heat seal layer. In addition, the easy peel property was also good.
On the other hand, in Comparative Examples 1 to 4 in which the unsaturated fatty acid amide was not included in the heat seal layer, the slipping property and the film forming property were inferior. Moreover, in Comparative Examples 2-4 in which the heat seal layer contains a saturated fatty acid amide, the transparency was further inferior.

  The film of the present invention is excellent in workability in each manufacturing process because the heat seal layer has slipperiness while maintaining good heat sealability and easy peelability even when sealed with sterilized paper or nonwoven fabric. From these viewpoints, the film of the present invention can be beneficially used, including post-process processing such as manufacturing of medical supplies, quality control, and user-friendliness.

Claims (5)

  A heat-sealable multilayer film having at least one heat-seal layer on a surface layer, at least one layer containing a polyamide-based resin, and a layer containing a polyolefin-based resin adjacent to the heat-seal layer, The heat-sealable multilayer film, wherein the heat-seal layer is a layer containing a resin composition of an ethylene-methyl acrylate copolymer (A) and an unsaturated fatty acid amide (B).   The heat-sealability according to claim 1, wherein the unsaturated fatty acid amide (B) has an unsaturated fatty acid having 18 to 22 carbon atoms and a melting point of the unsaturated fatty acid amide of 65 ° C or higher. Multilayer film.   The heat-sealable multilayer film according to claim 1 or 2, wherein a coefficient of dynamic friction between the heat-seal layer and the polyethylene film is 0.5 or less when measured according to JIS K7125.   The heat-sealable multilayer film according to any one of claims 1 to 3, wherein the heat-seal layer has an easy peel property.   A medical packaging body, wherein the heat seal layer of the heat-sealable multilayer film according to any one of claims 1 to 4 and a polyethylene non-woven fabric are heat-sealed.