JP2009178958A - Laminated body and packaging bag using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laminated body used for a packing bag which obtains an appropriate slidability and a stable low temperature sealability in the case of manufacturing the packing body and filling contents. <P>SOLUTION: In the laminated body, which is composed of three layers formed by laminating a layer A, a layer B and a layer C, in this order, using an ethylene-α olefine copolymer polymerized by using a single site-based catalyst, the densities of the layer A, B and C are 0.890-0.920, 0.925-0.935 and 0.890-0.920, respectively, and the density gradient is (density of the layer B)>(density of the layer A)>(density of the layer C). The laminated body is used for the packing bag. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to providing a laminate excellent in low-temperature sealability and slipperiness at the time of bag making and filling contents, and a packaging bag using the same.

  Laminates (sealants) used on the innermost surface of packaging bags for pharmaceuticals, foods, non-foods, etc. use lubricants as additives to ensure the suitability for packaging and filling the contents. Yes. Since this lubricant has a low molecular weight and moves in the laminate, it is often put in excess. This excessive lubricant has a problem that the lubricant adheres to a machine or the like at the time of bag making or filling and becomes a foreign matter. In addition, especially in pharmaceutical products, there are problems such as the adverse effect of lubricants on the contents.

  An object of the present invention is to provide a packaging bag that reduces the amount of lubricant, and ensures the suitability for bag-making of a package, the suitability for filling contents, and the low-temperature sealing property.

  FIG. 1 is an explanatory cross-sectional view showing an example of the layer structure of the packaging bag of the present invention. FIG. 1 shows a configuration in which a laminate 2 is laminated on one surface of a film substrate 1 with an adhesive layer D interposed therebetween. FIG. 2 is a cross-sectional explanatory view showing the layer structure of another example of a packaging bag, in which a barrier layer E is laminated on one side of a film substrate 1 via an adhesive layer D, and further laminated via an adhesive layer D. The body 2 is laminated.

  The invention of claim 1 of the present invention is a laminate comprising three layers laminated in the order of layer A, layer B and layer C using an ethylene-α olefin copolymer polymerized using a single site catalyst. The density of the A layer is 0.890 to 0.920, the density of the B layer is 0.925 to 0.935, the density of the C layer is 0.890 to 0.920, and the density gradient is the density of the B layer. > A layer density> C layer density.

The invention according to claim 2 of the present invention is the laminate according to claim 1, wherein 1 to 10% by weight of an inorganic filler having an average particle diameter of 3 to 20 μm is added to the C layer.
A third aspect of the present invention is a packaging bag using the laminate according to the first or second aspect and having the C layer as an innermost surface.
The invention according to claim 4 of the present invention is the packaging bag according to claim 3, wherein a film base material is laminated on the laminate.
The invention according to claim 5 of the present invention is the packaging bag according to claim 4, wherein a gas barrier layer is provided between the film substrate and the laminate.

  Conventionally, in order to avoid the problem caused by excessive lubricant, if the lubricant is simply made into a low additive formulation, the slipperiness is deteriorated, and problems may occur during bag making or content filling. Therefore, in the present invention, the laminated body has a three-layer structure, and by increasing the resin density of the layers other than the seal layer in contact with the contents, the slipperiness necessary for the bag making suitability for the package and the filling suitability for the contents is ensured. It was decided to. Moreover, the low temperature sealing property is ensured by not changing the density of the sealing layer in contact with the contents.

  If the slipping property of the C layer in contact with the contents in the laminate is poor, problems such as meandering occur when a packaging bag using the laminate is made, resulting in a problem of poor yield. In addition, when the contents are filled, the contents do not enter the packaging bag well, a filling failure occurs, and the work efficiency decreases.

  Accordingly, the present invention provides a technique for improving the slipperiness of a film formed from an ethylene-α olefin copolymer polymerized using a single site catalyst. An ethylene-α-olefin copolymer polymerized using a single-site catalyst has a narrow molecular weight distribution and a small amount of low molecular weight, and therefore has little stickiness. Moreover, heat sealing at a low temperature is possible.

  As the types of additives, those using an inorganic filler were suitable for this purpose, and those having a particle size in the range of 3 to 20 μm showed good results. When the particle size of the inorganic filler is less than 3 μm, there is no effect in improving the slipperiness, and when the particle size exceeds 20 μm, the container surface is rubbed and damaged by the inorganic filler protruding on the surface. There is. Moreover, it is preferable that the addition amount of the said inorganic filler is the range of 1-10 weight%. If the amount added is less than 1% by weight, there is no effect of slipperiness, and if it exceeds 10% by weight, the container surface may be rubbed and damaged by the inorganic filler protruding on the surface. As an addition method of the inorganic filler, it can be added by an ordinary masterbatch blend method at the time of melt extrusion.

According to the present invention, by providing a density gradient between the three layers of the laminate, it is possible to provide a laminate having both sliding properties and low-temperature sealing properties. That is, when the lubricant that contributes to slipperiness exists in the polymer, it exists in the amorphous part, not in the crystalline part of the polymer. That is, since the polymer tends to form crystals when the density is high, the lubricant is less likely to be present in the resin having a high density. Therefore, even if the concentration of the lubricant in the A layer, the B layer, and the C layer is the same, for example, if the density of the B layer is higher than that of the A layer and the C layer, the lubricant moves to the A layer and the C layer. As a result, more A layer and C layer exist than B layer.
In order to improve the slipperiness while maintaining the characteristics of the ethylene-α-olefin copolymer polymerized using these single-site catalysts, a density gradient is added between the constituent layers of the multilayer film formation and an inorganic system is used. We succeeded in securing the necessary slipperiness by adding filler to form a film. As a result, it is possible to ensure the slipperiness necessary for the bag making suitability and the filling suitability of the contents, and heat sealing at a low temperature is possible.

  Hereinafter, an embodiment of a packaging bag having the laminate of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional explanatory view showing the layer structure of the packaging bag of the present embodiment. FIG. 1 shows a configuration in which a laminate 2 is laminated on one surface of a film substrate 1 with an adhesive layer D interposed therebetween. FIG. 2 is a cross-sectional explanatory view showing the layer structure of another embodiment of the packaging bag, in which a barrier layer E is laminated on one side of the film substrate 1 via an adhesive layer D, and further through an adhesive layer D. The laminated body 2 is laminated.

  The film substrate 1 is made of a colorless and transparent polymer material, and has mechanical strength and dimensional stability such as polyethylene terephthalate (PET), polypropylene (PP), nylon (Ny), polyethylene naphthalate (PEN). Those are preferred, and these are processed into a film and further stretched in the biaxial direction.

  The thickness of the film substrate 1 is not particularly limited. However, in consideration of suitability as a packaging material, workability when laminating other films or forming a deposited thin film layer, etc., the range of 5 to 50 μm. Is preferred.

The barrier layer E is a film having a vapor-deposited thin film layer (not shown) of inorganic oxide, and the vapor-deposited thin film is made of silicon oxide, aluminum oxide or magnesium oxide, and the film thickness thereof is in the range of 5 to 300 nm. Desirably, the value is appropriately selected. The film thickness of the deposited thin film layer is 5n
If it is m or less, a uniform thin film may not be formed on the entire surface of the film, and the function as a gas barrier material may not be sufficiently achieved. In addition, when the thickness of the deposited thin film layer exceeds 300 nm, the deposited thin film cannot maintain flexibility, and the deposited thin film may be cracked due to external factors such as bending and pulling after the deposition. Not good for that.

  As the barrier layer E, a barrier laminated film in which a gas barrier coating layer (not shown) made of a polyvinyl alcohol resin and an inorganic layered compound is further laminated on the vapor-deposited thin film layer may be used. Particularly high gas barrier properties can be obtained by setting the blending ratio of the resin and the inorganic stratiform compound in the range of 60/40 to 40/60 of the polyvinyl alcohol resin / inorganic stratiform compound by weight percentage.

  The polyvinyl alcohol resin is generally obtained by saponifying polyvinyl acetate, and several tens percent of acetic acid groups remain. A completely saponified polyvinyl alcohol in which only several percent of acetic acid groups remain from a so-called partially saponified polyvinyl alcohol resin. Including resin, it is not particularly limited.

As the adhesive layer D, a polyurethane-based adhesive is generally used. Usually, a two-component type is used in which a main component having a hydroxyl group and a curing agent having an isocyanate group are mixed in two components. The coating method can also be a known coating method such as a gravure coating method. The coating amount is preferably 1 to 5 g / m ² (dry state).

  The laminate 2 is made of an ethylene-α-olefin copolymer resin polymerized using a single site catalyst, and the lamination method is not particularly limited, but a multilayer coextrusion method in which the resin is melt-extruded at the same time is preferably used. The thickness is appropriately selected, but a thickness of about 15 to 100 μm is used.

Hereinafter, the laminated body of this invention and a packaging bag using the same are demonstrated based on a specific Example.
<Example 1>
Single-site catalyst via polyurethane adhesive D applied to a coating amount of 3 g / m ² (dry state) on a biaxially stretched polypropylene film having a thickness of 30 μm on a film substrate 1 by a dry laminating machine. A laminated bag 2 of 50 μm-thick ethylene-α-olefin copolymer resin film polymerized using was laminated to create a packaging bag. The layered product 2 had a film thickness ratio of A: B: C = 1: 1: 1, and densities of A layer 0.920, B layer 0.925, and C layer 0.910. Further, 3 wt% of silicon oxide filler having an average particle diameter of 6 μm was added to the C layer.
<Example 2>
A packaging bag of the present invention was produced in the same manner as in Example 1 except that the density of the B layer of the ethylene-α-olefin copolymer resin film 2 polymerized using a single site catalyst was 0.935.
<Example 3>
The film substrate 1 has a thickness of 12 μm via a polyurethane adhesive D applied to a coating amount of 3 g / m ² (dry state) on a biaxially stretched polypropylene film having a thickness of 30 μm by a dry laminating machine. A barrier layer E in which a deposited film layer of silicon oxide having a thickness of 50 nm was laminated on a biaxially stretched polyester film was laminated. Subsequently, ethylene having a thickness of 50 μm was polymerized using a single-site catalyst via a polyurethane adhesive D having a coating amount of 3 g / m ² (dried state) applied onto the deposited thin film layer of the barrier layer E. The laminate 2 of the α-olefin copolymer resin film was bonded to create a packaging bag. The layered product 2 had a film thickness ratio of A: B: C = 1: 1: 1, and densities of A layer 0.920, B layer 0.925, and C layer 0.910. Further, 3 wt% of silicon oxide filler having an average particle diameter of 6 μm was added to the C layer.
<Example 4>
A packaging bag of the present invention was produced in the same manner as in Example 3 except that the density of the B layer of the laminate 2 of the ethylene-α-olefin copolymer resin film polymerized using a single site catalyst was 0.935. did.
<Comparative Example 1>
Example 1 except that the density of the A layer of the laminate 2 of the ethylene-α-olefin copolymer resin film polymerized using a single site catalyst was 0.910 and the density of the B layer was 0.910. A packaging bag was produced in the same manner.
<Comparative example 2>
Example 3 except that the density of the A layer of the laminate 2 of the ethylene-α-olefin copolymer resin film polymerized using a single site catalyst was 0.910 and the density of the B layer was 0.920. A packaging bag was produced in the same manner.

The slidability and low-temperature sealability of the packaging bag prepared by the above method were evaluated.
<Evaluation method>
・ Measure slipping of packaging bags:
The static friction coefficient of the surface of the C layer of the packaging bag was measured by an inclination method for calculating the static friction coefficient from the angle at which sliding started.
・ Low temperature sealability of packaging bags:
Heat seal conditions: Temperature 160 ° C., pressure 196 KPa (actual pressure), time 1 second heat seal strength measurement (conforms to JIS Z1707)

From the results in Table 1, the static friction coefficient was reduced and improved in Examples 1 and 2 compared to Comparative Example 1. Further, no decrease was observed in Comparative Example 2 as compared with Comparative Example 1. The static friction coefficient was decreased and improved in Examples 3 and 4 as compared with Comparative Example 3. The heat seal strength was the same in both the comparative example and the example.

  From the above, since the heat seal strength is equivalent to that of the conventional products (Comparative Examples 1 and 2), the laminate of the present invention maintains the low temperature sealing property that is a feature of the ethylene-α-olefin copolymer resin film. Thus, it was confirmed that the slipperiness of the package was improved as compared with the conventional products (Comparative Examples 1 and 2).

Cross-sectional explanatory drawing which shows one Embodiment of the layer structure of the packaging bag which has a laminated body of this invention Cross-sectional explanatory drawing which shows one Embodiment of the layer structure of the packaging bag which has a laminated body of this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Film base material 2 ... Laminated body (ethylene-alpha olefin copolymer resin)
A ... ethylene-α olefin copolymer resin layer B ... ethylene-α olefin copolymer resin layer C ... ethylene-α olefin copolymer resin layer D ... adhesive layer E ... barrier layer

Claims (5)

  In the laminated body which consists of three layers laminated | stacked in order of the A layer, the B layer, and the C layer using the ethylene-alpha olefin copolymer polymerized using the single site type catalyst, the density of A layer is 0.890- 0.920, the density of the B layer is 0.925 to 0.935, the density of the C layer is 0.890 to 0.920, and the density gradient is the density of the B layer> the density of the A layer> the density of the C layer. A laminate characterized by the above.  The laminate according to claim 1, wherein 1 to 10% by weight of an inorganic filler having an average particle diameter of 3 to 20 μm is added to the C layer.   A packaging bag using the laminate according to claim 1 or 2 as an innermost surface.   The packaging bag according to claim 3, wherein a film base material is laminated on the laminate.  The packaging bag according to claim 4, wherein a gas barrier layer is provided between the film substrate and the laminate.