JP2018176691A - Polyethylene-based sealant film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyethylene-based sealant film that has a tearing property required on a packaging material while suppressing an increase in an addition amount of an antistatic agent.SOLUTION: A base layer part 10, a sealant layer part 20 and a laminate layer part 30 are provided, the base layer part contains linear low density polyethylene having 1-butene as a comonomer as a base layer part composition resin, the sealant layer part contains linear low density polyethylene having 1-hexene as a comonomer as a sealant layer part composition resin, the laminate layer part contains as the laminate layer part composition resin mainly made of the linear low density polyethylene, a melting point of the laminate layer part composition resin is 123°C or higher, the melting point of the laminate layer part composition resin is set higher than melting points of the base layer part composition resin and sealant layer part composition resin, and the antistatic agent is added at 1.5 mass% or lower of an entire weight in the sealant film.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a polyethylene-based sealant film, and more particularly to a polyethylene-based sealant film having both good tear performance and antistatic performance.

  In many films used for food packaging and the like, a sealant film is laminated to a stretched base film such as polyamide or polyester. Non-oriented polyethylene or the like is used as a material of the sealant film. The packaging film is processed into an appropriate bag shape by heat sealing or the like. Then, articles such as food are filled. In the packaging film, the sealant film side contacts contents such as food.

  In various contents, articles with poor polarity, for example, flours such as wheat flour and oat flour are also present. When packaging such powdery material, if the sealant film is not subjected to any treatment, the powdery material adheres to the sealant film side due to the influence of static electricity, and the contents can not be taken out well. In addition, the powder may adhere to the opening even when the powder is filled. Then, it is likely to cause a fusion failure of the sealing portion by heat sealing.

  From this, the antistatic agent has been added to the sealant film. A kneading type etc. are known as an antistatic agent. This type of antistatic agent is incorporated into the resin of the film, and the antistatic agent appears on the film surface by bleeding. However, although the amount of the antistatic agent can be controlled, the actual amount of bleeding (the amount that leaks to the surface) largely varies depending on the environment. If the amount of bleeding is excessive, the laminate tends to be defective. Further, if the amount of bleed is too small, the desired static electricity suppressing effect can not be exhibited. In addition, the sealant film and the other top substrate film are adhered by an adhesive (dry lamination). However, it is also known that the antistatic agent moves to the adhesive side and the concentration on the side in contact with the content of the sealant film decreases.

  Apart from this flow, tearability (easiness to cut) is one of the properties required for the packaging film. Ease of opening is important as a product appealing effect. As mentioned above, it is common to add antistatic agents into the film. However, it is difficult to selectively bleed the antistatic agent on the side in contact with the content of the sealant film, and bleeding also occurs on the side to be dry laminated. As a result, the adhesive for dry lamination is also affected, and the adhesive strength (laminate strength) between the sealant film and the other front substrate film tends to be reduced. As a result, it is far from the desired tearability, and the attractiveness such as usability as a packaging film is reduced.

  As the said description, the antistatic function and tearability (easiness to cut) in a sealant film are not easily compatible. In view of this point, for example, a film blended with high-pressure low density polyethylene has been proposed (see Patent Document 1). Moreover, a film which does not contain a slip agent in the film has been proposed (see Patent Document 2).

  However, it has not been satisfactory for a film that has both good expression of antistatic performance and good tearing property of the package after dry lamination. In particular, assuming the packaging of powdery materials, development of a film which has been required to be easy to open has been awaited.

JP 2001-64456 A JP, 2004-339398, A

  After that, the inventors have made intensive studies and reviewed the composition resin of the polyethylene-based sealant film, and have come to develop a sealant film which exhibits satisfactory antistatic performance and also achieves good tear performance.

  The present invention has been proposed in view of the above-mentioned situation, and in a polyethylene-based sealant film, it exhibits good antistatic performance while suppressing the addition amount of the antistatic agent, and the tearability required for the packaging material is good. To provide a polyethylene-based sealant film that also combines

  That is, according to the first aspect of the invention, the base material layer portion, the sealant layer portion disposed on the first surface side of the base material layer portion, and the laminate layer portion disposed on the second surface side of the base material layer portion It is a sealant film provided, and the substrate layer portion is composed of one or both of linear low density polyethylene having 1-butene as a comonomer or linear low density polyethylene having a long chain branch as a substrate layer portion composition resin And the melt flow rate (190 ° C., 2.16 kg load) of the base layer composition resin is 1 to 15 g / 10 min, and the sealant layer has a linear low density polyethylene having 1-hexene as a comonomer. Or one or both of linear low density polyethylene having 1-octene as a comonomer as a sealant layer composition resin, and the laminate layer part The laminate layer portion composition resin mainly containing low density polyethylene is contained, and the melt flow rate (190 ° C., 2.16 kg load) of the laminate layer portion composition resin is 1 to 15 g / 10 min, and the laminate layer portion composition The melting point of the resin is 123 ° C. or higher, the melting point of the laminate layer composition resin is higher than the melting point of the base layer composition resin, and the melting point of the laminate layer composition resin is the melting point of the sealant layer composition resin The present invention relates to a polyethylene-based sealant film characterized in that the antistatic agent is added to the sealant film in an amount of not more than 1.5% by weight based on the total weight of the sealant film.

  A second invention relates to the polyethylene-based sealant film according to the first invention, wherein the antistatic agent is a glycerin-fatty acid ester-based antistatic agent.

  A third invention relates to the polyethylene-based sealant film according to the first invention, wherein the antistatic agent is a mixture of two or more kinds of glycerin-fatty acid ester-based antistatic agents.

  According to a fourth aspect of the present invention, the thickness ratio of the laminate layer portion of the sealant film, the base layer portion, and the sealant layer portion in the order is 1: 1: 1 to 1: 10: 1. The polyethylene-based sealant film according to any one of the items 1 to 3.

  5th invention is the measurement of the tearing load of the said sealant film based on JISK7128-2 (1998), The tearing load of 50 micrometers conversion of the film forming direction of the said sealant film is 4 N or less, and 50 micrometers of the width direction The polyethylene-based sealant film according to any one of the first to fourth inventions, wherein the reduced tear load is 8 N or less.

  According to the polyethylene-based sealant film according to the first invention, the substrate layer portion, the sealant layer portion disposed on the first surface side of the substrate layer portion, and the second surface side of the substrate layer portion A sealant film comprising a laminate layer portion, wherein the substrate layer portion is based on one or both of linear low density polyethylene having 1-butene as a comonomer or linear low density polyethylene having a long chain branch. Material layer composition resin contained, the melt flow rate (190 ° C., 2.16 kg load) of the base material layer composition resin is 1 to 15 g / 10 min, and the sealant layer part has 1-hexene as a comonomer Sealant layer composition resin, one or both of linear low density polyethylene and linear low density polyethylene having 1-octene as a comonomer Contained as a laminate layer composition resin mainly composed of linear low density polyethylene, and the melt flow rate (190 ° C., 2.16 kg load) of the laminate layer composition resin is 1 to 15 g / 10 min, the melting point of the laminate layer composition resin is 123 ° C. or more, the melting point of the laminate layer composition resin is higher than the melting point of the base layer composition resin, and the laminate layer composition resin The melting point of the resin is higher than the melting point of the sealant layer composition resin, and the antistatic agent is added to the sealant film in an amount of 1.5% by weight or less of the total weight of the sealant film. While producing a polyethylene-based sealant film that exhibits good antistatic performance and also has good tearability required for packaging materials Door can be.

  According to the polyethylene-based sealant film according to the second invention, in the first invention, since the antistatic agent is a glycerin-fatty acid ester-based antistatic agent, the effect can be exhibited even with a small amount of addition.

  According to the polyethylene-based sealant film according to the third invention, in the first invention, the antistatic agent is a mixture of two or more types of glycerin-fatty acid ester-based antistatic agents, so the effect can be obtained even with a small amount of addition. It is easy to obtain the effect of the antistatic agent, and the amount of addition can be further reduced.

  According to the polyethylene-based sealant film of the fourth invention, in any one of the first to third inventions, the thickness in the order of the laminate layer portion, the base material layer portion, and the sealant layer portion of the sealant film Since the ratio of is 1: 1: 1 to 1: 10: 1, the range which can be used as a sealant film is covered and replacement with the existing sealant film is also easy.

  According to the polyethylene-based sealant film of the fifth invention, in any of the first to fourth inventions, in the measurement of the tear load of the sealant film according to JIS K 7128-2 (1998), the sealant film of Since the tear load in 50 μm conversion in the film forming direction is 4 N or less and the tear load in 50 μm conversion in the width direction is 8 N or less, tearing and opening etc. become easy.

It is a schematic cross-sectional schematic diagram of the polyethylene-type sealant film of this invention. It is a schematic cross-sectional schematic diagram which shows the usage example of the sealant film of FIG.

  The schematic cross-sectional schematic view of FIG. 1 is a structural example of the sealant film 1 which is the "polyethylene-based sealant film" of the present invention. The polyethylene-based sealant film is laminated with another resin film 40 alone or later. In the sealant film 1, the innermost surface 21 which is the surface of the sealant layer 20 contacts the article to be packaged. And when processed into a bag shape, the innermost surfaces 21 are mutually fused by heat sealing. Another film, aluminum foil or the like is laminated on the outermost surface 32 of the laminate layer portion 30 via an adhesive or the like for lamination. Therefore, the laminate film 5 is configured including the sealant film 1 (see FIG. 2). Applications of the laminate film 5 including the sealant film 1 are perishable foods, processed foods, food packaging materials such as confectionery products, packaging materials such as detergents, cosmetics, and other medicines. Of course, other than this, it is used suitably.

  The sealant film 1 mainly comprises the following three layers. The base material layer portion 10 is placed at the center, and the sealant layer portion 20 is disposed on the first surface 11 side of the base material layer portion 10. In addition, the laminate layer portion 30 is disposed on the second surface 12 side of the base material layer portion 10. The sealant film 1 has a three-layer structure and is formed by a known technical manufacturing method such as T-die coextrusion. The example described later is film formation by non-stretching of T-die coextrusion. The distinction between the first surface 11 or the second surface 12 of the base material layer portion 10 is treated as a matter of convenience, and changes in the formation surface are allowed.

  The base layer portion 10 is composed of the base layer portion composition resin (R1). The base layer composition resin (R1) is either one or both of linear low density polyethylene having 1-butene as a comonomer and linear low density polyethylene having a long chain branch. Linear low density polyethylene is preferably metallocene catalyzed polymerization. When using only linear polyethylene, adjustment by adjusting the density is difficult. Therefore, polyethylene having a proper branching site in the molecule is selected. The base layer composition resin (R1) is a single species or a mixture of two. Therefore, the physical properties in the case of single resin mixture of two kinds of resins are comprehensively grasped as the base material layer composition resin (R1). The melt flow rate of the measurement based on JISK 7210-1 (2014) is used. The melt flow rate (190 ° C., 2.16 kg load) of the base layer composition resin (R1) is 1 to 15 g / 10 min.

  When the melt flow rate of the base material layer composition resin (R1) is less than 1 g / 10 min, the flowability is insufficient, and the film formation is impaired. In the case where the melt flow rate exceeds 15 g / 10 min, on the contrary, the flowability becomes excessive, which is not preferable from the point of stabilization of the base layer portion 10. In addition, the resistance to heat sealing and the like also decreases. In particular, the base material layer part composition resin (R1) is a resin that constitutes the base material layer part 10 at the center of the sealant film 1. For this reason, shape stabilization is important. Therefore, the melt flow rate of the base layer composition resin (R1) falls within the above range from the balance of performance.

  The sealant layer 20 is composed of a sealant layer composition resin (R2). The sealant layer portion composition resin (R2) is either one or both of linear low density polyethylene having 1-hexene as a comonomer and linear low density polyethylene having 1-octene as a comonomer. The sealant layer composition resin (R2) is also a single species or a mixture of two. Therefore, the physical properties in the case of a mixture of two kinds of resins alone are comprehensively grasped as a sealant layer composition resin (R2). Also for the sealant layer composition resin (R2), when using only linear polyethylene only, adjustment by adjusting the density is difficult. Therefore, a polyethylene resin having a proper branched site in the molecule is selected. Also, the selection of the resin type is for controlling the melting point described later.

  The laminate layer portion 30 is composed of a laminate layer portion composition resin (R3), and the resin (R3) mainly contains linear low density polyethylene. Moreover, high-density polyethylene etc. may be mix | blended as a resin whose melting | fusing point is higher than linear low density polyethylene from the objective of melting | fusing point control. Linear low density polyethylene of laminate layer composition resin (R3), base layer composition resin (R1) and sealant layer composition resin (R2) has tensile strength, tear resistance, impact resistance, seal strength And excellent in stress cracking resistance and the like. However, the linear low density polyethylene resin of the laminate layer composition resin (R3) is not as restricted in molecular structure as the resin of each layer described above.

  In addition, in the melt flow rate (190 degreeC, the 2.16-kg load) of the measurement based on JISK 7210-1 (2014) of a lamination layer part composition resin (R3), it is 1 to 15 g / 10min. When the melt flow rate of the laminate layer portion composition resin (R3) is less than 1 g / 10 min, the fluidity is insufficient and film formation is impaired. In the case where the melt flow rate exceeds 15 g / 10 min, on the contrary, the flowability becomes excessive, which is not preferable from the viewpoint of stabilization of the laminate layer portion 30.

  Base material layer composition resin (R1) constituting base material layer part 10, sealant layer composition resin (R2) constituting sealant layer part 20, and laminate layer composition resin (R3) constituting laminate layer part 30 In the selection of each resin, the gradient of the melting point of the composition resins R1, R2 and R3 is also added to the index. The gradient between the melting points of the composition resins R1, R2 and R3 can be a factor to control bleeding of the later-described antistatic agent.

  Specifically, the laminate layer portion composition resin (R3) constituting the laminate layer portion 30 is selected from resins having a melting point (Tm3) higher than 123 ° C. The lower limit of 123 ° C. is in anticipation of resin selection of the base material layer composition resin (R1) constituting the base material layer part 10 immediately below the laminate layer part 30 and the sealant layer composition resin (R2) constituting the sealant layer 20 It is the lower limit value of the melting point set.

  The melting point (Tm3) of the laminate layer portion composition resin (R3) constituting the laminate layer portion 30 is higher than the melting point (Tm1) of the base layer portion composition resin (R1) constituting the base layer portion 10. The melting point (Tm3) of the laminate layer composition resin (R3) constituting the laminate layer part 30 is higher than the melting point (Tm2) of the sealant layer composition resin (R2) constituting the sealant layer 20. In addition, as long as melting | fusing point (Tm1) and melting | fusing point (Tm2) satisfy | fill the relationship with melting | fusing point (Tm3), both melting | fusing point or different melting | fusing point are accept | permitted.

  The reason why the melting point (Tm3) of the laminate layer composition resin (R3) is higher than the melting point (Tm1) of the base material layer composition resin (R1) and the melting point (Tm2) of the sealant layer composition resin (R2) It is for suppressing the bleed | bleed to the lamination layer part side of an inhibiting agent. The lower the melting point of the resin, the easier it is to move the antistatic agent. Therefore, the bleeding due to the movement of the antistatic agent into and out of the layer tends to be large. By designing the highest melting point (Tm3) of the laminate layer composition resin (R3) by utilizing this property, the transfer of the antistatic agent to the laminate layer part and the adhesive for laminating can be restricted. .

The layer structure of the sealant film 1 is a three-layer structure of "laminate layer portion 30 / base material layer portion 10 / sealant layer portion 20" as shown in FIG. The total thickness of the sealant film 1 is suitably in the range of 20 to 150 μm. In FIG. 1, the thickness of the base layer portion 10 in the sealant film 1 is “t ₁ ”, the thickness of the sealant layer portion 20 is “t ₂ ”, and the thickness of the laminate layer portion 30 is “t ₃ ”. The relation of the thickness of each layer is expressed as the order of “t ₃ : t ₁ : t ₂ ”. The thickness ratio (relative ratio) of each layer of the sealant film 1 is approximately “1: 1: 1” to “1: 10: 1” in the order of the laminate layer portion 30, the base layer portion 10, and the sealant layer portion 20. It is a range. The range covers the range that can be used as a sealant film, and replacement with existing sealant films is easy.

  The antistatic agent to be added to the sealant film 1 is selected from a kneading type, and among these, a glycerin-fatty acid ester type antistatic agent is preferably used. Furthermore, the same glycerin-fatty acid ester antistatic agent is preferably a mixture of two or more kinds of glycerin fatty acid ester-based antistatic agents. The glycerin-fatty acid ester type antistatic agent is a compound of a monoglyceride in which a fatty acid is ester bonded to one or two hydroxyl groups of glycerin which is a triol, and a fatty acid ester of a compound of diglyceride in which another glycerin is further bonded to one hydroxyl group of glycerin. Can be mentioned. The ester-linked fatty acid is a long-chain fatty acid having 12 to 20 carbon atoms, and is an ester compound of fatty acid such as palmitic acid and stearic acid. Examples are the use of glycerin monostearate, diglycerin monostearate, diglycerin monopalmitate.

  The glycerin-fatty acid ester type antistatic agent can exert effects even with a small amount of addition. Therefore, the influence on the resin composition constituting the film can be made minor. Moreover, by using a mixture of two or more types of glycerin-fatty acid ester-based antistatic agent, the effect of the antistatic agent can be easily obtained, and the addition amount can be further reduced.

  The addition amount of the antistatic agent in the sealant film 1 is 1.5% by weight or less, more preferably 1% by weight or less of the total weight of the sealant film. The addition destination of the antistatic agent is the base layer portion 10, or both the base layer portion 10 and the sealant layer portion 20, or the laminate layer 30 or the like. If the addition amount exceeds this amount, the influence of the bleeding of the antistatic agent may greatly affect the adhesion of the laminate described later.

  For the sealant film 1 in the series of explanations, the tear of the film itself is also required. Therefore, the Elmendorf tear strength of the sealant film 1 is determined in the evaluation. The measurement of the tearing load of the sealant film conforms to JIS K 7128-2 (1998), and the tearing load in terms of 50 μm in the film forming direction (MD (also referred to as length direction or winding direction)) of the sealant film 1 is 4N. And the tear load in the width direction (TD) in terms of 50 μm is 8 N or less. In addition, since the thickness of a film influences, the measured value of each tear load is converted into fixed thickness (50 micrometers in an Example). From the relationship of directionality at the time of film formation of the sealant film, the tear load on the film forming direction (MD) side of the sealant film 1 is lower in numerical value than the width direction (TD). When the sealant film 1 generally meets the above-mentioned tearing load, tearing and opening etc. become easy.

  The sealant film 1 is combined with another resin film 40 mainly to show a schematic cross-sectional schematic view of FIG. Thereafter, the laminate film 5 is cut, subjected to heat sealing and the like, and then made into a bag. Then, contents such as powder are filled and sealed in the bag.

  At the time of processing into the laminate film 5, the resin film 40 is laminated (laminated) on the surface (the outermost surface 32) of the laminate layer portion 30 of the sealant film 1 by a known method. FIG. 2 shows an example in which an adhesive layer 50 for laminating is formed. The material of the resin film 40 is appropriate, and various resin films such as a polypropylene film, a polyethylene terephthalate film, a nylon resin (polyamide resin) film, and a film of polylactic acid can be mentioned. The number and type of the layers of the resin film 40 are not limited to one, and a plurality of types of layers are laminated. Furthermore, lamination of a thin film of aluminum is also possible.

  As a result, the sealant film is given new properties such as structural strength, durability, light resistance, and printing properties. In addition to the above-mentioned antistatic agent, additives such as an antiblocking agent, a slip agent, an antioxidant, a neutralizing agent, and a coloring agent are added to the sealant film of the present invention as required. The type of additive is appropriately selected depending on the application.

  When the package (fill) of the bag-like material of the laminate film 5 is wheat flour, oat flour, starch starch, coffee powder, other powders, the nonpolar powder is generally affected by static electricity. Therefore, it is easy to adhere to the innermost surface 21 on the sealant layer 20 side of the sealant film 1. That is, the remaining amount in the bag after opening is large, and it is difficult to take out the entire content of the bag. Therefore, as described above, an antistatic agent is added to the sealant film 1 to reduce the effect of static electricity.

  However, the antistatic agent contained in the sealant film 1 bleeds and penetrates also to the adhesive for bonding the laminate film 5. As a result, the adhesion of the adhesive bonding the two layers may be reduced. When tearing the laminated film 5 of the bag-made product, a gap occurs between the sealant film 1 and the resin film 40, and the entire laminated film 5 becomes difficult to tear at once. Here, when the amount of the antistatic agent is suppressed with awareness of the bleed, the antistatic performance of the film is reduced, which makes the film unsuitable for packaging of the powdery material described above.

  From such a point of view, it is required to achieve both the securing of the antistatic performance of the film and the improvement of tearing accompanied by the reduction of the influence of the bleed on the adhesive for laminating and the like. Thus, the sealant film of the present invention has been realized through the selection of the polyethylene resin of each layer and the control of the melting point, and further, the adjustment of the amount of the antistatic agent to be added.

[Preparation of polyethylene-based sealant film]
With respect to the polyethylene-based sealant films of Examples 1 to 9 and Comparative Examples 1 to 3, based on the compounding ratio (parts by weight) of each layer shown in Tables 1 to 3 below, both the resin as the raw material and the antistatic agent are used. It melt | melted and knead | mixed and formed into a film by non-stretching using a co-extrusion T-die film forming machine. The thicknesses of the polyethylene-based sealant films of Examples and Comparative Examples were adjusted by setting at the time of co-extrusion, and the thickness ratio (thickness ratio) of the layers constituting the films was also shown in the table. With respect to the raw materials used, the blending ratio is 100% by weight in total in each layer portion of the laminate layer portion, the base material layer portion, and the sealant layer portion.

[Used raw material]
The following "resin 1" to "resin 8" were used as raw resin. In the table, it is described as "resin 1" or the like.
{Resin 1}: Linear low density polyethylene with 1-hexene / C6-LLDPE
Ube Maruzen Polyethylene Co., Ltd., trade name "Umille (registered trademark) 4040 FC", MFR: 3.5 g / 10 min, melting point: 126 ° C., density: 0.938 g / cm ³
{Resin 2}: Linear low density polyethylene with 1-hexene / C6-LLDPE
Ube Maruzen Polyethylene Co., Ltd., trade name “Umille (registered trademark) 3540 FC”, MFR: 3.6 g / 10 min, melting point: 123 ° C., density: 0.931 g / cm ³
{Resin 3}: Linear low density polyethylene with 1-hexene / C6-LLDPE
Ube Maruzen Polyethylene Co., Ltd., trade name “Umille (registered trademark) 2040 FC”, MFR: 5 g / 10 min, melting point: 117 ° C., density: 0.919 g / cm ³
{Resin 4}: Linear low density polyethylene with 1-butene / C4-LLDPE
Ube Maruzen Polyethylene Co., Ltd., trade name “Umille (registered trademark) 715FT”, MFR: 4 g / 10 min, melting point: 113 ° C., density: 0.913 g / cm ³
{Resin 5}: Linear low density polyethylene with 1-hexene / C6-LLDPE
Ube Maruzen Polyethylene Co., Ltd., trade name "Umille (registered trademark) 2540 F", MFR: 4 g / 10 min, melting point: 119 ° C., density: 0.923 g / cm ³
{Resin 6}: Linear low density polyethylene with 1-hexene / C6-LLDPE
Ube Maruzen Polyethylene Co., Ltd., trade name “Umille (registered trademark) 1540 F”, MFR: 4 g / 10 min, melting point: 99 ° C. and 114 ° C., density: 0.913 g / cm ³
{Resin 7}: High density polyethylene / HDPE
Nippon Polyethylene Co., Ltd., trade name "HF 560", MFR: 7 g / 10 min, melting point: 134 ° C, density: 0.963 g / cm ³
{Resin 8}: Linear low density polyethylene having long chain branching Sumitomo Chemical Co., Ltd., trade name "CB2001", MFR: 2 g / 10 min, melting point: 106 ° C., density: 0.920 g / cm ³

The following “As1” to “As4” were used as antistatic agents. In the table, it is written as "As1" or the like.
{As1}: Glycerin monostearate {As2}: diglycerin monostearate {As3}: diglycerin monopalmitate {As4}: nonionic surfactant organic sulfonate

  Anti-blocking agents, slip agents, antioxidants, and neutralizing agents were used as other compounding ingredients. Since these are trace amounts, they are not described in the table.

[Production of laminated film]
An aluminum-deposited biaxially stretched polyester film (trade name "DIARASTER FK", thickness 12 μm) was used as a film (laminated film) to be laminated on a sealant film.

About 4 g / m ^{2 of} an adhesive prepared for dry lamination was applied to the surface of the above-mentioned laminated film, and the adhesive was once dried. The adhesive was prepared by Toyo Morton Co., Ltd., main agent: TM-329, curing agent: CAT-8B, solvent: ethyl acetate. Thereafter, the laminated film portion side of the polyethylene-based sealant film of the example and the comparative example was laminated with the above-described laminated film to obtain a laminated film.

[Measurement]
Melt flow rate
The MFR of each resin was 190 ° C. and 2.16 kg load based on the measurement of the melt flow rate according to JIS K 7210-1 (2014).

[Melting point]
In each layer part, in case of using a single resin, the melting point of the resin specification was used. On the other hand, when two or more types of resins were mixed and used, pelletized resins were dry-blended according to the formulation according to the formulation of each example, and melt mixed through a single screw extruder to prepare samples. The melting point of the sample was determined from differential scanning calorimetry (DSC) in accordance with JIS K 7121 (2012).

〔thickness〕
The thickness of each sealant film of Examples and Comparative Examples was measured in accordance with JIS K 7130 (1999).

[Elmendorf tear strength]
The measurement of Elmendorf tear strength of each sealant film of Examples and Comparative Examples conformed to JIS K 7128-2 (1998). The sealant film of each example was cut into a film forming direction (MD) 76 mm and a width direction (TD) 63 mm to obtain a sealant film test piece. The film forming direction (MD) and width direction (TD) Elmendorf tear strength (unit: N) of rectangular sealant film test pieces were measured using a tear tester (SA-WP) manufactured by Toyo Seiki Co., Ltd. . Each tear strength was converted to a thickness of 50 μm according to formula (i) to obtain Elmendorf tear strength in both directions in the sealant films of the examples and comparative examples.

[Trouser tear strength]
About the laminate film which included the sealant film of an Example and a comparative example, the measurement of the trouser tear strength was based on JISK7128-1 (1998). When measuring the tear strength in the film forming direction (MD), cut 150 mm × 50 mm rectangular MD test pieces with the long side in the width direction (TD) of each laminate film and the short side in the film forming direction (MD) . A 75 mm notch is made in the longitudinal direction of the MD test specimen from the middle point of the short side, and both pieces are pulled in opposite directions to each other, and the load (N) when the tear amount reaches 50 mm (tearing strength of MD ) Was measured (unit: N).

  In the measurement of the tear strength in the width direction (TD), each laminate film was cut into a 50 mm × 150 mm rectangular TD test piece with the width direction (TD) of the laminated film as the short side and the film forming direction (MD) as the long side. Then, insert a 75 mm notch in the longitudinal direction of the test piece for TD from the middle point of the short side, pull both pieces in the opposite direction to each other, and the load (N) at the time when the tear amount reaches 50 mm (TD Tear strength was measured (unit: N). A universal testing machine autograph AG-1 manufactured by Shimadzu Corporation was used to measure the trouser tear strength.

[Surface resistivity]
The surface resistivity was measured according to JIS K 6911 (1995) for each of the sealant films of the examples and comparative examples and the laminate film including the sealant film (unit: Ω / □). For measurement, Hiresta-UX MCP-HT800 high resistance resistivity meter manufactured by Mitsubishi Chemical Corporation was used.

  In Tables 1 to 3, types and amounts (% by weight) of raw resin and antistatic agent for each layer of the polyethylene sealant films of Examples 1 to 9 and Comparative Examples 1 to 3, melting point (° C.), and antistatic agent Represents the weight ratio (% by weight) of the entire sealant film. In addition, the thickness (μm) of the sealant film, layer ratio, Elmendorf tear load (N) (MD side and TD side), surface resistivity (Ω / □) (laminate layer portion side and sealant layer portion side) are shown. , Trouser tear load (N) (at the sealant film side) for the laminated film.

[Results and Discussion of Polyethylene Sealant Film]
[Resin composition]
The base layer composition resin of Comparative Example 1 is a linear low density polyethylene resin having 1-hexene as a comonomer. In Comparative Example 1, the Elmendorf tearing load increased significantly. On the other hand, the base layer composition resin of the other embodiment is a linear low density polyethylene resin having 1-butene as a comonomer or a linear low density polyethylene resin having a long chain branch. According to the result of using the resin, Elmendorf tearing load could be suppressed.

  In the sealant layer portion composition resin of the sealant layer portion, any of the examples is a linear low density polyethylene resin having 1-hexene as a comonomer. As a result, it was good without influence on each index. The lamination layer part composition resin of a lamination layer part was usable regardless of the kind of comonomer. Also, high-density polyethylene is for the purpose of adjusting the melting point, and no influence on physical properties was observed.

[Relationship of melting point]
Focusing on the melting points (Tm1, Tm2, Tm3) of the composition resin of each layer of the polyethylene sealant film, Comparative Example 2 is an example in which the melting point on the laminate layer portion side is lower than that of the other layers. Here, the addition amount of the antistatic agent of Example 1 and the comparative example 2 is the same amount, and the addition destination is also common in the base material layer part. However, the surface resistivity of the laminate film using the sealant film of Comparative Example 2 was increased. In this respect, the antistatic agent contained in the film bleeds to the laminate layer portion side and further to the laminate adhesive due to the influence of the difference of the resin melting point, and the bleed to the originally desired sealant layer portion side is relative. I guess it is because it decreased to

  Moreover, about melting | fusing point (Tm3) of a lamination layer part composition resin, it can be said that 123 degreeC or more is suitable from the result of Example 2, 8. Thus, it is significant that the directivity of the bleed of the antistatic agent can be controlled by mutually adjusting the melting points of the resin composition of each layer of the polyethylene-based sealant film. The relationship between the melting points of the resins is “Tm3 ≧ 123 ° C.”, and “Tm3> Tm1” and “Tm3> Tm2” hold.

[Antistatic agent amount and type]
Example 5 is an example of using an antistatic agent other than the glycerin-fatty acid ester type. Also in this example, although the surface resistivity is good, the amount of addition is relatively large. On the other hand, another example is a usage example of a glycerin-fatty acid ester type antistatic agent, and sufficient performance was exhibited even with a lower amount. Therefore, when looking at the addition amount of the antistatic agent in the total weight of the sealant film, the addition of no additive in Comparative Example 3 was effective out of 0.15% by weight of Example 1 as an exception. Then, when the upper limit including Example 5 is taken into consideration, it is 1.5% by weight. When limiting to the glycerin-fatty acid ester system, the upper limit can be considered to be 1% by weight or less, and further 0.7% by weight or less.

[Thickness ratio]
From the series of examples, it was possible to form the film as the structure of a normal three-layer sealant film for setting the thickness ratio. Therefore, the thickness ratio in the order of the laminate layer portion, the base layer portion, and the sealant layer portion is 1: 1: 1 to 1: 10: 1.

[Tear load]
According to the Elmendorf tearing load of the sealant film in the table, in each of the examples, the load on the MD side was 4N or less, and the load on the TD side was 8N or less. From the comparison with Comparative Example 1, when the value of the tear load is large, it becomes an obstacle to tearability. It was also found from the numerical value of the tearing load of the comparative example 1 that the tearing was not easy. Then, when it is going to ensure tearability while securing the strength of the sealant film, each value on the MD side and the TD side of the example becomes a standard of good or bad. For each lower limit, approximately 1N can be considered.

  The present invention is a polyethylene-based sealant film, which exhibits good antistatic performance while suppressing the addition amount of the antistatic agent, can also have good tearability required for packaging materials, and is easy to open, etc. It has the ability to contribute to product value. Therefore, it is advantageous as a substitute for the conventional polyethylene-based sealant film. In addition, it is a good example for powdery materials.

DESCRIPTION OF SYMBOLS 1 polyethylene system sealant film 5 laminate film 10 base material layer part 11 1st surface of base material layer part 12 2nd surface of base material layer part 20 sealant layer part 21 innermost layer 30 laminate layer part 32 outermost surface 40 resin film 50 adhesion Agent layer t ₁ base layer thickness t ₂ sealant layer thickness t ₃ laminate layer thickness

Claims (5)

A substrate layer portion (10), a sealant layer portion (20) disposed on the first surface side of the substrate layer portion, and a laminate layer portion (30) disposed on the second surface side of the substrate layer portion A sealant film (1) provided with
The base layer portion (10) contains either or both of linear low density polyethylene having 1-butene as a comonomer or linear low density polyethylene having long chain branches as a base layer composition resin (R1) The melt flow rate (190 ° C., 2.16 kg load) of the base layer composition resin (R1) is 1 to 15 g / 10 min,
The sealant layer portion (20) contains either one or both of linear low density polyethylene having 1-hexene as a comonomer or linear low density polyethylene having 1-octene as a comonomer as a sealant layer composition resin (R2) And
The laminate layer portion (30) is contained as a laminate layer portion composition resin (R3) mainly composed of linear low density polyethylene, and the melt flow rate (190 ° C., 2.16 kg load) of the laminate layer portion composition resin (R3) ) Is 1 to 15 g / 10 min,
The melting point (Tm3) of the laminate layer composition resin (R3) is 123 ° C. or higher, and the melting point (Tm3) of the laminate layer composition resin (R3) is the melting point (Tm1) of the base layer composition resin (R1) And the melting point (Tm3) of the laminate layer composition resin (R3) is higher than the melting point (Tm2) of the sealant layer composition resin (R2).
A polyethylene-based sealant film characterized in that the antistatic agent is added to the sealant film (1) in an amount of not more than 1.5% by weight based on the total weight of the sealant film (1).   The polyethylene-based sealant film according to claim 1, wherein the antistatic agent is a glycerin-fatty acid ester-based antistatic agent.   The polyethylene-based sealant film according to claim 1, wherein the antistatic agent is a mixture of two or more glycerin-fatty acid ester-based antistatic agents.   The thickness ratio of the sealant film (1) in the order of the laminate layer portion (30), the base material layer portion (10), and the sealant layer portion (20) is 1: 1: 1 to 1:10. The polyethylene-based sealant film according to any one of claims 1 to 3, which is 1.   In the measurement of the tear load of the sealant film (1) according to JIS K 7128-2 (1998), the tear load in terms of film formation (MD) of the sealant film (1) in 50 μm is 4 N or less, and the width The polyethylene-based sealant film according to any one of claims 1 to 4, wherein a tear load in the direction (TD) in terms of 50 μm is 8 N or less.

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