Polyethylene-based unoriented film and film laminate

Abstract

This invention provides polyethylene-based unoriented films and film laminates that achieve both semi-permanent antistatic properties and slipperiness, not only in the film alone but also after dry lamination. [Solution] A polyethylene-based unstretched film 10 for dry lamination comprising a base layer 20 and a sealant layer 30, wherein the base layer 20 is mainly composed of linear low-density polyethylene, and the sealant layer 30 contains 70-90% by weight of linear low-density polyethylene and 10-30% by weight of a polymer-type antistatic agent, the polymer-type antistatic agent being a copolymer of a hydrophilic polymer and a modified polyolefin with a volume resistivity of 1 × 10 5 ~1 × 10 11 It is an acid-modified polyolefin polyether block polymer with a mass of Ω·cm, and when the total amount of each resin material in the unstretched film 10 is 100 parts by weight, it contains at least 0.035 parts by weight of unsaturated fatty acid amide and at least 0.012 parts by weight of unsaturated fatty acid bisamide in terms of the total layer.

Description

[Technical Field]

[0001] The present invention relates to polyethylene-based unoriented films and film laminates using polyethylene-based unoriented films, and more particularly to polyethylene-based unoriented films and film laminates that achieve both semi-permanent antistatic properties and slipperiness. [Background technology]

[0002] In many packaging materials used for food packaging and other purposes, a film laminate is used in which a sealant film made of polyethylene-based unstretched film or the like is laminated onto a stretched base film such as polyamide or polyester by dry lamination. The film laminate, which is the packaging material, is processed into a suitable bag shape by heat sealing or the like, and then filled with food or other items. In the packaging that contains the contents of the food or other items, the sealant film of the film laminate is on the inner side of the bag, and therefore the sealant film side comes into contact with the contents.

[0003] Various contents include powders such as wheat flour and buckwheat flour. When packaging such powders, if the sealant film is not treated in any way, static electricity can cause the powder to adhere to the sealant film, making it difficult to remove the contents properly. Also, when filling with powders, there is a risk of powder adhering to the opening. This can easily lead to poor fusion of the heat-sealed area.

[0004] Therefore, in polyethylene-based unoriented films that constitute sealant films, an antistatic agent is added to the resin material to impart antistatic properties. Examples of antistatic agents added to polyethylene-based unoriented films include low-molecular-weight antistatic agents and high-molecular-weight antistatic agents. When a low-molecular-weight antistatic agent is added, it is mixed into the resin material, and after film molding, the low-molecular-weight antistatic agent bleeds out to the film surface, thereby exhibiting antistatic properties and providing an antistatic effect.

[0005] However, in polyethylene-based unoriented films to which low-molecular-weight antistatic agents are added, the actual amount of bleed varies greatly depending on environmental factors such as temperature (room temperature) and humidity. If the amount of bleed is excessive, it results in poor appearance (whitening), and if the amount of bleed is insufficient, the desired antistatic effect is not achieved. Furthermore, wiping with water or organic solvents may reduce the antistatic performance. In addition, when polyethylene-based unoriented films are used as sealant films and laminated to base films by dry lamination, the antistatic agent may migrate to the adhesive, leading to a decrease in laminate strength and a reduction in the concentration of the antistatic agent on the sealant film surface (the side in contact with the contents), resulting in the desired antistatic effect not being achieved.

[0006] When a polymer-type antistatic agent is added, a conductive circuit is formed by the addition of a phase-separated structure with the resin material, thereby providing semi-permanent antistatic properties. Examples of films to which polymer-type antistatic agents are added include a multilayer film (see Patent Document 1) consisting of a layer made of an antistatic resin composition having a structure in which blocks of polyolefin and blocks of hydrophilic polymer having a predetermined volume resistivity are repeatedly and alternately bonded, and a base layer made of a thermoplastic resin, and an antistatic clean film (see Patent Document 2) consisting of 90-60% by weight of linear low-density polyethylene without additives and 40-10% by weight of a polymer-type antistatic agent.

[0007] Incidentally, this type of packaging requires certain film properties such as transparency and slipperiness. However, conventional films with added polymer-type antistatic agents have semi-permanent antistatic properties but insufficient slipperiness, meaning they do not offer both semi-permanent antistatic properties and good slipperiness. Therefore, when a lubricant commonly used in polyethylene-based unoriented films with added low-molecular-weight antistatic agents was added to a film with added polymer-type antistatic agents, it was found that the slipperiness deteriorated when the base film was laminated by dry lamination. [Prior art documents]

Patent Document

[0008]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0009] The present invention has been proposed in view of the above points, and provides a polyethylene-based non-stretched film and a film laminate that can achieve both semi-permanent antistatic properties and slipperiness not only in the case of a single film but also when a base film is laminated by dry lamination.

Means for Solving the Problems

[0010] That is, the first invention is a polyethylene-based non-stretched film for dry lamination comprising at least two layers including a base layer mainly composed of a polyethylene-based resin and a sealant layer. The base layer is made of a resin material mainly composed of linear low-density polyethylene, and the sealant layer is a layer with a thickness of 2 μm or more composed of an antistatic resin composition containing 70 to 90% by weight of linear low-density polyethylene and 10 to 30% by weight of a polymer-type antistatic agent. The polymer-type antistatic agent is an acid-modified polyolefin polyether block polymer having a volume resistivity of 1×10 5 ~1×10 11 Ω·cm, which is a copolymer of a hydrophilic polymer and a modified polyolefin. When the total of each resin material constituting the polyethylene-based non-stretched film is 100 parts by weight, it is characterized in that the total layer conversion amount of unsaturated fatty acid amide is 0.035 parts by weight or more and the total layer conversion amount of unsaturated fatty acid bisamide is 0.012 parts by weight or more.

[0011] The second invention is, in the first invention, the melt flow rate (at 190 °C, 2.16 kg load) of the linear low-density polyethylene in the antistatic resin composition is 1 to 6 g / 10 min and the density is 0.860 to 0.935 g / cm 3 and relates to a non-stretched polyethylene film.

[0012] The third invention is, in the first or second invention, the haze of the non-stretched polyethylene film is 8% or less and relates to a non-stretched polyethylene film.

[0013] The fourth invention is, in the first or second invention, the surface resistivity of the surface on the sealant layer side of the non-stretched polyethylene film aged at 35 °C for 7 days is less than 1 × 10 13 Ω / □ and the coefficient of kinetic friction of each surface on the base material layer side and the sealant layer side is 0.3 or less and relates to a non-stretched polyethylene film.

[0014] The fifth invention is, in the first or second invention, a non-stretched polyethylene film in which a surface layer made of a resin material mainly composed of linear low-density polyethylene is laminated on the side of the base material layer opposite to the sealant layer.

[0015] The sixth invention is, in the third invention, a non-stretched polyethylene film in which a surface layer made of a resin material mainly composed of linear low-density polyethylene is laminated on the side of the base material layer opposite to the sealant layer.

[0016] The seventh invention is, in the fourth invention, a non-stretched polyethylene film in which a surface layer made of a resin material mainly composed of linear low-density polyethylene is laminated on the side of the base material layer opposite to the sealant layer.

[0017] The eighth invention relates to a film laminate characterized in that a film to be laminated portion is provided on the side of the base material layer of the non-stretched polyethylene film according to the first or second invention opposite to the sealant layer side.

[0018] The ninth invention relates to a film laminate characterized in that a laminated film portion is provided on the side of the base layer of the polyethylene-based unoriented film described in the third invention that is opposite to the sealant layer side.

[0019] The tenth invention relates to a film laminate characterized in that a laminated film portion is provided on the side of the base layer of the polyethylene-based unoriented film described in the fourth invention that is opposite to the sealant layer side.

[0020] The eleventh invention relates to a film laminate characterized in that a laminated film portion is provided on the side of the surface layer of the polyethylene-based unoriented film described in the fifth invention that is opposite to the side of the base material layer.

[0021] The twelfth invention relates to a film laminate characterized in that a laminated film portion is provided on the side of the surface layer of the polyethylene-based unoriented film described in the sixth invention that is opposite to the side of the base material layer.

[0022] The 13th invention relates to a film laminate characterized in that a laminated film portion is provided on the side of the surface layer of the polyethylene-based unoriented film described in the 7th invention that is opposite to the side of the base material layer.

[0023] The 14th invention relates to the 8th invention, wherein the surface resistivity of the sealant layer side of the film laminate aged at 40°C for 7 days is 1 × 10⁻⁶. 13 The present invention relates to a film laminate having a coefficient of friction less than Ω / □ and a coefficient of dynamic friction of 0.5 or less on the surface facing the sealant layer. [Effects of the Invention]

[0024] According to the first invention, the polyethylene-based unoriented film is a polyethylene-based unoriented film for dry lamination comprising at least two layers, including a base layer mainly composed of a polyethylene resin and a sealant layer, wherein the base layer is made of a resin material mainly composed of linear low-density polyethylene, and the sealant layer is a layer with a thickness of 2 μm or more, made of an antistatic resin composition containing 70-90% by weight of linear low-density polyethylene and 10-30% by weight of a polymer-type antistatic agent, wherein the polymer-type antistatic agent is a copolymer of a hydrophilic polymer and a modified polyolefin with a volume resistivity of 1 × 10⁻¹⁶ 5 ~1 × 10 11 This is an acid-modified polyolefin polyether block polymer with a density of Ω·cm. When the total amount of each resin material constituting the polyethylene-based unstretched film is 100 parts by weight, it contains at least 0.035 parts by weight of unsaturated fatty acid amide and at least 0.012 parts by weight of unsaturated fatty acid bisamide. Therefore, it is possible to achieve both semi-permanent antistatic properties and slipperiness not only in the film itself but also when the base film is laminated by dry lamination.

[0025] According to the polyethylene-based unstretched film of the second invention, in the first invention, the melt flow rate (190°C, 2.16 kg load) of the linear low-density polyethylene in the antistatic resin composition is 1 to 6 g / 10 min and the density is 0.860 to 0.935 g / cm³. 3 Therefore, the film exhibits good performance in terms of transparency, appearance, moldability, and blocking properties.

[0026] According to the polyethylene-based unoriented film of the third invention, in the first or second invention, since the haze of the polyethylene-based unoriented film is 8% or less, a polyethylene-based unoriented film with the transparency required for applications such as packaging films can be obtained.

[0027] According to the polyethylene non-stretched film according to the fourth invention, in the first or second invention, the surface resistivity of the surface on the sealant layer side of the polyethylene non-stretched film aged at 35°C for 7 days is 1×10 13 less than Ω / □ and the coefficient of kinetic friction of each surface on the base material layer side and the sealant layer side is 0.3 or less, so a polyethylene non-stretched film can be obtained in which appropriate antistatic properties and slipperiness are continuously compatible.

[0028] According to the polyethylene non-stretched film according to the fifth invention, in the first or second invention, a surface layer made of a resin material mainly composed of linear low-density polyethylene is laminated on the side of the base material layer opposite to the sealant layer, so the practicality can be enhanced as a packaging film or the like.

[0029] According to the polyethylene non-stretched film according to the sixth invention, in the third invention, a surface layer made of a resin material mainly composed of linear low-density polyethylene is laminated on the side of the base material layer opposite to the sealant layer, so the practicality can be enhanced as a packaging film or the like.

[0030] According to the polyethylene non-stretched film according to the seventh invention, in the fourth invention, a surface layer made of a resin material mainly composed of linear low-density polyethylene is laminated on the side of the base material layer opposite to the sealant layer, so the practicality can be enhanced as a packaging film or the like.

[0031] According to the film laminate according to the eighth invention, a film laminate that appropriately balances semi-permanent antistatic properties and slipperiness can be obtained because a film to be laminated is provided on the side of the base material layer of the polyethylene non-stretched film according to the first or second invention opposite to the sealant layer side.

[0032] According to the film laminate of the ninth invention, since the laminated film portion is provided on the side of the base layer of the polyethylene-based unoriented film described in the third invention that is opposite to the sealant layer side, a film laminate is obtained that appropriately achieves both semi-permanent antistatic properties and slipperiness.

[0033] According to the film laminate of the 10th invention, since the laminated film portion is provided on the side of the base layer of the polyethylene-based unoriented film described in the 4th invention that is opposite to the sealant layer side, a film laminate is obtained that appropriately achieves both semi-permanent antistatic properties and slipperiness.

[0034] According to the film laminate of the 11th invention, since the laminated film portion is provided on the side of the surface layer of the polyethylene-based unoriented film described in the 5th invention that is opposite to the base material layer, a film laminate is obtained that appropriately achieves both semi-permanent antistatic properties and slipperiness.

[0035] According to the film laminate of the 12th invention, since the laminated film portion is provided on the side of the surface layer of the polyethylene-based unoriented film described in the 6th invention that is opposite to the base material layer, a film laminate is obtained that appropriately achieves both semi-permanent antistatic properties and slipperiness.

[0036] According to the film laminate of the 13th invention, since the laminated film portion is provided on the side of the surface layer of the polyethylene-based unoriented film described in the 7th invention that is opposite to the base material layer, a film laminate can be obtained that appropriately balances semi-permanent antistatic properties and slipperiness.

[0037] According to the film laminate of the 14th invention, in the 8th invention, the surface resistivity of the sealant layer side of the film laminate aged at 40°C for 7 days is 1 × 10⁻⁶. 13 Since the coefficient of friction is less than Ω / □ and the coefficient of dynamic friction of the surface on the sealant layer side is 0.5 or less, a film laminate is obtained in which appropriate antistatic properties and slipperiness are continuously maintained. [Brief explanation of the drawing]

[0038] [Figure 1] This is a schematic cross-sectional view of a film laminate using a polyethylene-based unoriented film according to one embodiment of the present invention. [Figure 2] This is a schematic cross-sectional view of a film laminate using a polyethylene-based unstretched film according to another embodiment. [Modes for carrying out the invention]

[0039] The polyethylene-based unoriented film of the present invention comprises at least two layers, including a base layer and a sealant layer, which are mainly composed of polyethylene resin. In particular, it is a polyethylene-based unoriented film for dry lamination, used to form a film laminate by laminating a base film by dry lamination. This polyethylene-based unoriented film functions, for example, as a sealant film for a film laminate. A film laminate using the polyethylene-based unoriented film of the present invention is suitably used, for example, as packaging material for packaging powdered materials such as wheat flour and buckwheat flour.

[0040] The polyethylene resin used in the polyethylene-based unoriented film of the present invention is selected from linear low-density polyethylene (LLDPE), high-density polyethylene (HDPE), low-density polyethylene (LDPE), etc., either individually or in appropriate combinations. The polyethylene resin is appropriately selected from resins produced from appropriate starting materials such as petroleum-derived, biomass-derived, material-recycled, and chemical-recycled materials. From the viewpoint of reducing environmental impact, polyethylene resins derived from recycled materials such as material recycling and chemical recycling, or biomass, are preferred. Examples of biomass-derived polyethylene resins include polyethylene resins obtained by processing plant materials. Specifically, this refers to polyethylene resins produced by generating ethanol from a sugar solution extracted from plant materials such as sugarcane through alcoholic fermentation by yeast, followed by ethyleneification, and then using a known resinification process. The higher the weight proportion of biomass-derived polyethylene resin, the greater the contribution to reducing environmental impact.

[0041] In the polyethylene-based unoriented film of the present invention, various additives such as antioxidants, neutralizing agents, anti-fogging agents, nucleating agents, and colorants, as well as scraps, can be added to each layer as needed, within limits that do not impair the properties of each layer. The various additives may be added directly to the powder after polymerization of each resin, or they may be mixed in any step before obtaining the film using a high-concentration masterbatch. When using a masterbatch, a small amount of resin may be unintentionally incorporated, but it can be used within limits that do not impair the properties of each layer.

[0042] The polyethylene-based unoriented film of the present invention is obtained by melting the resins constituting each layer and forming them to a predetermined thickness using known film forming methods such as the T-die method or the inflation method. In particular, forming by the T-die method is preferred. Film forming by the T-die method is advantageous in that it can obtain the high thickness-to-thinness accuracy required for a film. In this invention, cases in which the film is subjected to unavoidable stretching during film formation are also included in the definition of unoriented.

[0043] The polyethylene-based unoriented film and film laminate using the polyethylene-based unoriented film of the present invention will be described in detail using embodiments shown in Figures 1 and 2. In Figures 1 and 2, the same reference numerals represent the same components, and their descriptions are omitted. It should be noted that the polyethylene-based unoriented film and film laminate of the present invention are not limited to the embodiments shown in Figures 1 and 2.

[0044] Figure 1 shows a film laminate 1 using a polyethylene-based unoriented film 10 according to one embodiment of the present invention, wherein the polyethylene-based unoriented film 10 is provided with a laminated film portion 50. The polyethylene-based unoriented film 10 according to the illustrated embodiment is composed of two layers: a base layer 20 and a sealant layer 30.

[0045] The base layer 20 is the main layer of the polyethylene-based unoriented film 10, and is formed with a thicker layer thickness compared to other layers. It is made of a resin material mainly composed of linear low-density polyethylene. High-density polyethylene and low-density polyethylene may be added to the resin material constituting the base layer 20 as appropriate.

[0046] In the linear low-density polyethylene used in the base layer 20, the melt flow rate (MFR) is not particularly limited. For example, linear low-density polyethylene with an MFR of 0.1 to 30 g / 10 min, particularly 1 to 15 g / 10 min, measured under conditions of 190°C and a load of 2.16 kg in accordance with JIS K 7210-1 (2014), is preferably used. If the MFR of the linear low-density polyethylene is too low, it may result in poor appearance and deterioration of moldability. If the MFR is too high, it may result in poor thickness accuracy and excessive fluidity during sealing, which may adversely affect the sealing performance of the sealed area. If the MFR value of the linear low-density polyethylene is within the above range, appropriate physical properties as a sealant film can be ensured.

[0047] The density of the linear low-density polyethylene used in the base layer 20 is not particularly limited. For example, a density of 0.965 g / cm³ measured under the conditions described in JIS K 7112 (2023) is acceptable. 3The following, in particular, is 0.950 g / cm³. 3 The following linear low-density polyethylene is preferably used. If the density of the linear low-density polyethylene is too high, the impact resistance may deteriorate. If the density of the linear low-density polyethylene is within the above range, appropriate physical properties as a sealant film can be ensured.

[0048] The sealant layer 30 is the inner surface layer of the bag when it is made into a package, and is composed of an antistatic resin composition that provides both sealing and antistatic properties. The antistatic resin composition is a resin composition containing 70-90% by weight of linear low-density polyethylene and 10-30% by weight of a polymer-type antistatic agent.

[0049] For the linear low-density polyethylene used in the sealant layer 30, the melt flow rate (MFR) is preferably 1 to 6 g / 10 min, measured under conditions of 190°C and a load of 2.16 kg, in accordance with JIS K 7210-1 (2014). If the MFR of the linear low-density polyethylene is too low, poor appearance and poor moldability may occur. If the MFR is too high, the transparency of the film may deteriorate. If the MFR value of the linear low-density polyethylene is within the above range, excellent transparency and a good appearance can be obtained, as well as good moldability.

[0050] For the linear low-density polyethylene used in the sealant layer 30, the density measured under the conditions described in JIS K 7112 (2023) is 0.860 to 0.935 g / cm³. 3 This is preferable. If the density of the linear low-density polyethylene is too low, blocking may occur easily. If the density is too high, the transparency of the film may deteriorate. If the density of the linear low-density polyethylene is within the above range, transparency and blocking properties will be good.

[0051] The polymer-type antistatic agent used in the sealant layer 30 is an antistatic agent that exhibits antistatic properties by forming a conductive circuit that releases the charge accumulated in the sealant layer when dispersed in the resin material. Since this polymer-type antistatic agent exhibits antistatic properties without migrating to the film surface (bleed-out), the antistatic properties are maintained for a long period of time (semi-permanently).

[0052] Polymeric antistatic agents consist of a copolymer of a hydrophilic polymer and a modified polyolefin. The hydrophilic polymer is preferably one generally referred to as a polyether, such as polyetherdiol, polyetherdiamine, polyetheresteramide, polyetheramideimide, polyetherurethane, polyetherester, polyetheramide, and modified versions thereof. The modified polyolefin is a polyolefin in which a carbonyl group, carboxyl group, amino group, hydroxyl group, etc., are introduced as a modifying group, and these are present at least at one end; carboxyl-modified polyolefins are preferred.

[0053] A polymeric antistatic agent is formed by suitably copolymerizing a hydrophilic polymer and a modified polyolefin. This polymeric antistatic agent has a volume resistivity of 1 × 10⁻¹⁶ according to ASTM D257 (2021). 5 ~1 × 10 11 It is preferable that the volume resistivity is Ω·cm. Volume resistivity is an indicator for determining how difficult it is for charge accumulated in the antistatic layer of the film to escape. 5 ~1 × 10 11 By setting the volume resistivity to Ω·cm, the film can achieve good antistatic performance. If the volume resistivity is too high, it may become difficult to release the charge accumulated in the antistatic layer of the film, potentially resulting in insufficient antistatic performance.

[0054] Therefore, among such polymeric antistatic agents, acid-modified polyolefin polyether block polymers are preferred. Acid-modified polyolefin polyether block polymers have good compatibility with linear low-density polyethylene constituting the sealant layer 30 and also exhibit excellent antistatic performance.

[0055] In polymer-type antistatic agents, the melt flow rate (MFR) is not particularly limited, but from the viewpoint of resin properties and processability, for example, the MFR measured under conditions of 190°C and a load of 2.16 kg in accordance with JIS K 7210-1 (2014) is preferably 1 to 50 g / 10 min, and more preferably 2 to 20 g / 10 min. In addition, in polymer-type antistatic agents, the melting point is not particularly limited, but from the viewpoint of resin properties and processability, for example, it is preferably 100 to 170°C.

[0056] In the antistatic resin composition for the sealant layer 30, linear low-density polyethylene and a polymer antistatic agent are kneaded together to disperse the polymer antistatic agent in the resin material. For example, it is preferable to dry blend linear low-density polyethylene and a polymer antistatic agent in the above-mentioned predetermined blending ratio in weight percent using a known mixer (tumbler, Henschel mixer, etc.), and then melt-knead them using a kneader such as a single-screw extruder, twin-screw extruder, or pressure kneader. By kneading in this manner, the polymer antistatic agent can be appropriately dispersed in the resin material. In this kneader, a twin-screw extruder is preferably used to enable finer dispersion of the polymer antistatic agent.

[0057] In the antistatic resin composition adjusted in this way, if there is too little linear low-density polyethylene, that is, if there is too much polymer-type antistatic agent, thickness defects may occur, making it impossible to form a film. If there is too much linear low-density polyethylene, that is, if there is too little polymer-type antistatic agent, the surface resistivity may increase, resulting in insufficient antistatic performance.

[0058] The sealant layer 30 is set to a thickness of 2 μm or more to ensure good antistatic performance. If the sealant layer 30 is too thin, the antistatic performance may be insufficient. However, there is no particular upper limit to the thickness of the sealant layer 30 as long as it is thinner than the thickness of the base layer 20. For example, if the sealant layer 30 is made thicker, it will not adversely affect the film performance, but since the polymer-type antistatic agent used in the antistatic resin composition is relatively expensive, if the sealant layer 30 is too thick, it may be disadvantageous in terms of manufacturing costs, etc. Therefore, from an economic standpoint, it is preferable to set the upper limit of the sealant layer 30 to about 10 μm.

[0059] In the polyethylene-based unoriented film 10 of the present invention, unsaturated fatty acid amides and unsaturated fatty acid bisamides are used as lubricants to impart slipperiness, and in particular, when the total amount of each resin material constituting the polyethylene-based unoriented film 10 is 100 parts by weight, the total amount of unsaturated fatty acid amides on a whole-layer basis is 0.035 parts by weight or more, and the total amount of unsaturated fatty acid bisamides on a whole-layer basis is 0.012 parts by weight or more.

[0060] Unsaturated fatty acid amides are lubricants used to impart slipperiness to polyethylene-based unoriented films. In particular, their relatively small molecular weight allows for a fast bleed rate to the film surface, resulting in early development of slipperiness. Therefore, appropriate slipperiness can be imparted to the polyethylene-based unoriented film 10 immediately after film formation. Examples of preferably used unsaturated fatty acid amides include erucic acid amide and oleic acid amide.

[0061] Unsaturated fatty acid bisamides are lubricants used to impart slipperiness to polyethylene-based unoriented films 10. In particular, because unsaturated fatty acid bisamides have a larger molecular weight compared to unsaturated fatty acid amides, their bleed rate to the film surface is slower than that of unsaturated fatty acid amides, allowing for the imparting of slipperiness over time. Examples of unsaturated fatty acid bisamides that are preferably used include ethylenebisoleamide and ethylenebiserucamide.

[0062] Thus, in the polyethylene-based unoriented film 10 of the present invention, the timing of the onset of slipperiness is controlled by using unsaturated fatty acid amides and unsaturated fatty acid bisamides with different molecular weights (different bleed rates) as lubricants. For example, an unsaturated fatty acid amide with a fast bleed rate imparts appropriate slipperiness immediately after film formation, enabling smooth winding of the film as a roll immediately after film formation. On the other hand, when the polyethylene-based unoriented film 10 is dry laminated, it has been found that unsaturated fatty acid amides that bleed out early onto the film surface are adsorbed by the adhesive used in dry lamination (especially polyether-based adhesives), reducing the slipperiness. Therefore, by including an unsaturated fatty acid bisamide with a relatively slow bleed rate, it bleeds out even after dry lamination, thus maintaining appropriate slipperiness even after dry lamination.

[0063] The unsaturated fatty acid amides and unsaturated fatty acid bisamides used as lubricants only need to be present in a predetermined amount in the entire polyethylene-based unoriented film 10 (total layer amount), and the layers in which they are contained and the content in each layer are not limited. For example, it is preferable to appropriately add unsaturated fatty acid amides or unsaturated fatty acid bisamides to the layer closest to the side where the slipperiness is to be exhibited (sealant layer 30 side) in order to efficiently exhibit the slipperiness. If the content of unsaturated fatty acid amides is too low, the slipperiness immediately after film formation may be insufficient, making it difficult to smoothly wind the film into a roll. If the content of unsaturated fatty acid bisamides is too low, it may be difficult to maintain the slipperiness after dry lamination.

[0064] In the polyethylene-based unoriented film 10 of the present invention, the thickness is not particularly limited and can be appropriately determined according to demand and application, for example, 10 to 100 μm is preferred, and 15 to 70 μm is more preferred.

[0065] Furthermore, the polyethylene-based unoriented film 10 of the present invention preferably has the transparency required for applications such as packaging films. The transparency of the film is expressed by the haze (%) measured in accordance with JIS K 7136 (2000). A preferred haze for this film is 8% or less. If the haze is too high, the transparency generally required for packaging films and the like will be insufficient, which is undesirable.

[0066] As described above, the polyethylene-based unoriented film 10 can achieve both semi-permanent antistatic properties and slipperiness after dry lamination. Antistatic properties are assessed using the surface resistivity in accordance with JIS K 6911 (2006) as an indicator of antistatic performance. The surface resistivity of the side facing the sealant layer 30 after aging for 7 days at 35°C, which is a condition simulating the product storage state of the film after film formation, is 1 × 10⁻⁶. 13 It is preferable that the surface resistivity is less than Ω / □. If the surface resistivity is too high, the antistatic performance may be insufficient. If the surface resistivity under the above conditions is appropriate, it can be assumed that the necessary antistatic performance is maintained even after a predetermined time has elapsed in the film after film formation, thus obtaining a polyethylene-based unoriented film that maintains appropriate antistatic performance over the long term.

[0067] Furthermore, regarding slipperiness, it is preferable that the coefficient of dynamic friction of each surface on the base layer 20 side and the sealant layer 30 side is 0.3 or less, using the coefficient of dynamic friction conforming to JIS K 7125 (1999) as an indicator. If the coefficient of dynamic friction of at least one surface on the base layer 20 side and the sealant layer 30 side is too high, the slipperiness may be insufficient. By ensuring that the surface resistivity of the surface on the sealant layer 30 side and the coefficient of dynamic friction of each surface on the base layer 20 side and the sealant layer 30 side are appropriate, a polyethylene-based unoriented film can be obtained that continuously achieves both appropriate antistatic properties and slipperiness.

[0068] In the polyethylene-based unoriented film 10 of the present invention, in order to broaden the range of applications as a sealant film, it is preferable that one side of the base layer 20 (the side opposite to the sealant layer 30) is surface-treated to have a wetting tension of 36 mN / m or more. Examples of surface treatments include atmospheric pressure plasma treatment, flame treatment, and corona discharge treatment. The wetting tension is measured by a wetting tension test method in accordance with JIS K 6768 (1999). If the wetting tension is less than 36 mN / m, it is undesirable as it may cause printing defects or lamination defects.

[0069] The laminated film portion 50 corresponds to the base film of the film laminate 1 and is laminated onto the polyethylene-based unoriented film 10. As shown in the figure, this laminated film portion 50 is laminated on the side of the base layer 20 of the polyethylene-based unoriented film 10 that is opposite to the sealant layer 30, thereby providing a film laminate suitable for use as packaging material. Examples of the laminated film portion 50 include biaxially oriented nylon film, biaxially oriented polypropylene film, and biaxially oriented polyethylene terephthalate film. By using the same material or substantially the same resin as the polyethylene-based unoriented film of the present invention for the laminated film portion 50, it is possible to realize monomaterialization of the resulting film laminate, and packaging materials and packaging bags using the film laminate.

[0070] The polyethylene-based unoriented film 10 and the film to be laminated 50 are laminated by a known dry lamination method. As the dry lamination, a known adhesive such as a polyether-based adhesive or a polyurethane-based adhesive is applied to the film to be laminated 50. After the adhesive dries, the film to be laminated 50 is bonded to the surface of the base layer 20 of the polyethylene-based unoriented film 10, and the polyethylene-based unoriented film 10 and the film to be laminated 50 are brought into close contact using a roller or the like to form a film laminate 1.

[0071] In the film laminate 1 obtained in this way, the sealant layer 30 side, which faces the inner surface of the bag when used as a packaging material, can achieve both semi-permanent antistatic properties and slipperiness after dry lamination. For antistatic properties, the surface resistivity conforming to JIS K 6911 (2006) was used as an indicator of antistatic performance, and the surface resistivity of the sealant layer 30 side after aging for 7 days at 40°C, which is a condition that simulates the aging state of the film laminate after dry lamination, was 1 × 10⁻⁶. 13 It is preferable that the surface resistivity is less than Ω / □. If the surface resistivity is too high, the antistatic performance after dry lamination may be insufficient. If the surface resistivity under the above conditions is appropriate, it can be assumed that the necessary antistatic performance is maintained in the film laminate produced by dry lamination even after a predetermined time has elapsed, thus obtaining a film laminate that maintains appropriate antistatic performance over a long period of time even after dry lamination.

[0072] Furthermore, regarding slipperiness, the coefficient of dynamic friction conforming to JIS K 7125 (1999) is used as an indicator, and it is preferable that the coefficient of dynamic friction of the surface on the sealant layer 30 side is 0.5 or less. If the coefficient of dynamic friction of the surface on the sealant layer 30 side is too high, the slipperiness may be insufficient. By having an appropriate surface resistivity and coefficient of dynamic friction of the surface on the sealant layer 30 side, a film laminate can be obtained that continuously achieves both appropriate antistatic properties and slipperiness.

[0073] Figure 2 shows a film laminate 1A using a polyethylene-based unoriented film 10A according to another embodiment of the present invention, wherein the polyethylene-based unoriented film 10A is provided with a laminated film portion 50. The polyethylene-based unoriented film 10A according to the illustrated embodiment is composed of three layers: a base layer 20, a sealant layer 30, and a surface layer 40.

[0074] The surface layer 40 is laminated on the side of the base layer 20 opposite to the sealant layer 30, forming a three-layer polyethylene-based unoriented film 10A, and is made of a resin material mainly composed of linear low-density polyethylene. High-density polyethylene or low-density polyethylene may be added to the resin material constituting the surface layer 40 as appropriate. The three-layer structure of the polyethylene-based unoriented film 10A, with the surface layer 40, enhances its practicality when used as a packaging film or the like.

[0075] For the linear low-density polyethylene used in the surface layer 40, the melt flow rate (MFR) and density are not particularly limited. However, similar to the base layer 20, the MFR measured under conditions of 190°C and a load of 2.16 kg in accordance with JIS K 7210-1 (2014) should be 0.1 to 30 g / 10 min, more preferably 1 to 15 g / 10 min, and the density measured under the conditions described in JIS K 7112 (2023) should be 0.965 g / cm³. 3 More preferably, 0.950 g / cm³ 3 The following applies: The surface layer 40 may use the same resin material as the base layer 20, or it may use a different resin material. If the MFR value and density value of the linear low-density polyethylene are within the above range, molding is easy, blocking does not occur, and the appearance and transparency are good.

[0076] In the polyethylene-based unoriented film 10A, as a lubricant to impart slipperiness, when the total amount of each resin material constituting the unoriented film 10A is 100 parts by weight, the total amount of unsaturated fatty acid amide on a layer-by-layer basis is 0.035 parts by weight or more, and the total amount of unsaturated fatty acid bisamide on a layer-by-layer basis is 0.012 parts by weight or more. The unsaturated fatty acid amide and unsaturated fatty acid bisamide used as lubricants only need to be present in a predetermined amount as a whole (total amount on a layer-by-layer basis) of the polyethylene-based unoriented film 10A, and the layers in which they are contained and the content in each layer are not limited. For example, similar to the polyethylene-based unoriented film 10, it is preferable to appropriately add unsaturated fatty acid amide and unsaturated fatty acid bisamide to the layer closer to the side where slipperiness is to be exhibited (sealant layer 30 side) because this allows for efficient development of slipperiness.

[0077] In the polyethylene-based unoriented film 10A of the present invention, the thickness is not particularly limited and is determined appropriately according to demand and application, for example, 10 to 100 μm is preferred, and 15 to 70 μm is more preferred. The ratio of the thicknesses of each layer is set appropriately, but from the viewpoint of ensuring good antistatic performance, it is preferable that the thickness of the sealant layer 30 is 2 μm or more and less than the thickness of the base layer 20 (preferably 10 μm or less), and that the surface layer:base layer ratio is 1:1 to 1:8.

[0078] Furthermore, in the polyethylene-based unoriented film 10A of the present invention, similar to the polyethylene-based unoriented film 10, it is preferable that the haze measured in accordance with JIS K 7136 (2000) as the transparency of the film is 8% or less. This provides the same excellent transparency required for applications such as packaging films as in the polyethylene-based unoriented film 10.

[0079] Furthermore, in the polyethylene-based unoriented film 10A, the surface resistivity of the side facing the sealant layer 30 after aging at 35°C for 7 days in accordance with JIS K 6911 (2006) is 1 × 10⁻¹⁰. 13 Preferably, the coefficient of dynamic friction of the sealant layer 30 side is 0.3 or less, conforming to JIS K 7125 (1999) as a slippery property, and the coefficient of dynamic friction of the sealant layer 30 side is 0.3 or less. This results in a polyethylene-based unoriented film that continuously achieves both appropriate antistatic properties and slippery properties. Furthermore, it is more preferable that the coefficient of dynamic friction of the surface layer 40 side is 0.3 or less as a slippery property.

[0080] In the polyethylene-based unoriented film 10A of the present invention, in order to broaden the range of applications as a sealant film, it is preferable that one side of the surface layer 40 (the side opposite to the base layer 20) is surface-treated to have a wetting tension of 36 mN / m or more. Examples of surface treatments include atmospheric pressure plasma treatment, flame treatment, and corona discharge treatment. The wetting tension is measured by a wetting tension test method in accordance with JIS K 6768 (1999). If the wetting tension is less than 36 mN / m, it is undesirable as it may cause printing defects or lamination defects.

[0081] As shown in the figure, the laminated film portion 50 is laminated by known dry lamination on the side opposite to the base material layer 20 of the surface layer 40 of the polyethylene-based unoriented film 10A, to form a film laminate 1A. In the film laminate 1A obtained in this way, appropriate antistatic properties and slipperiness can be continuously maintained even after dry lamination on the sealant layer 30 side, which becomes the inner surface of the bag when used as a packaging material. For example, similar to the film laminate 1, the surface resistivity of the sealant layer 30 side, which has been aged for 7 days at 40°C in accordance with JIS K 6911 (2006), is 1 × 10⁻⁶. 13 Preferably, the coefficient of dynamic friction of the surface on the sealant layer 30 side is 0.5 or less, conforming to JIS K 7125 (1999) as a slippery property, and the coefficient of dynamic friction of the surface on the sealant layer 30 side is 0.5 or less.

[0082] As described above, the polyethylene-based unoriented film of the present invention has a sealant layer which is a layer with a thickness of 2 μm or more made of an antistatic resin composition containing 70-90% by weight of linear low-density polyethylene and 10-30% by weight of a polymeric antistatic agent, and the polymeric antistatic agent is a copolymer of a hydrophilic polymer and a modified polyolefin with a volume resistivity of 1 × 10⁻⁶ 5 ~1 × 10 11This is an acid-modified polyolefin polyether block polymer with a mass of Ω·cm. When the total amount of each resin material constituting the polyethylene-based unoriented film is 100 parts by weight, it contains at least 0.035 parts by weight of unsaturated fatty acid amide and at least 0.012 parts by weight of unsaturated fatty acid bisamide across the entire layer. Therefore, it is possible to achieve both semi-permanent antistatic properties and slipperiness not only in the film itself but also when the base film is laminated by dry lamination.

[0083] Although not shown in the figures, in the polyethylene-based unoriented film of the present invention, if necessary, appropriate functional layers such as a printed layer or a vapor-deposited layer may be provided on the side of the substrate layer opposite to the sealant layer side, in addition to the surface layer.

[0084] Furthermore, by laminating a base film (film to be laminated) on the surface opposite to the sealant layer of the polyethylene-based unoriented film of the present invention, a film laminate suitable for use as a packaging material can be provided. In particular, on the sealant layer side, which becomes the inner surface of the bag when used as a packaging material, both semi-permanent antistatic properties and slipperiness after dry lamination can be achieved. In addition, in this film laminate, monomaterialization can be realized by using the same material or substantially the same resin as the polyethylene-based unoriented film of the present invention for the base film (film to be laminated). [Examples]

[0085] [Preparation of polyethylene-based unoriented film] In producing the polyethylene-based unoriented films of Prototype Examples 1-30 and Comparative Example 1, the materials described later were kneaded and melted according to predetermined mixing ratios (by weight %) and parts by weight. The raw materials, resin, unsaturated fatty acid amide, and unsaturated fatty acid bisamide were then co-extruded using the T-die method so that the substrate layer and sealant layer (2-layer structure) or the surface layer, substrate layer, and sealant layer (3-layer structure) were laminated in that order. After cooling with a cooling roll, corona discharge treatment was applied to the surface side of the substrate layer in the 2-layer structure or the surface side of the surface layer in the 3-layer structure to produce the polyethylene-based unoriented films of each prototype and comparative example. The resin composition of each layer in Prototype Examples 1-30 and Comparative Example 1 is shown in Tables 1-5 below.

[0086] [Materials used] The following polyethylene resins (linear low-density polyethylene), antistatic agents (high-molecular-weight antistatic agents, low-molecular-weight antistatic agents), and lubricants (unsaturated fatty acid amides, unsaturated fatty acid bisamides) were used as materials for each layer. For the high-molecular-weight antistatic agents, the volume resistivity was measured in accordance with ASTM D257 (2021) at a temperature of 23°C and a humidity of 50% RH. The melt flow rate (MFR) was measured in accordance with JIS K 7210 (2014) at a temperature of 190°C.

[0087] [Polyethylene resin] PE1: Linear low-density polyethylene, MFR (190℃, 2.16kg): 5.0g / 10min, Density: 0.919g / cm³ 3 • PE2: Linear low-density polyethylene, MFR (190℃, 2.16kg): 3.2g / 10min, Density: 0.890g / cm³ 3 • PE3: Linear low-density polyethylene, MFR (190℃, 2.16kg): 4.3g / 10min, Density: 0.913g / cm³ 3 • PE4: Linear low-density polyethylene, MFR (190℃, 2.16kg): 4.3g / 10min, Density: 0.918g / cm³ 3 • PE5: Linear low-density polyethylene, MFR (190℃, 2.16kg): 3.8g / 10min, Density: 0.924g / cm³ 3 • PE6: Linear low-density polyethylene, MFR (190℃, 2.16kg): 4.0g / 10min, Density: 0.931g / cm³ 3 • PE7: Linear low-density polyethylene, MFR (190℃, 2.16kg): 4.0g / 10min, Density: 0.937g / cm³ 3 • PE8: Linear low-density polyethylene, MFR (190℃, 2.16kg): 4.0g / 10min, Density: 0.944g / cm³ 3 PE9: Linear low-density polyethylene, MFR (190℃, 2.16kg): 2.0g / 10min, Density: 0.913g / cm³ 3 PE10: Linear low-density polyethylene, MFR (190℃, 2.16kg): 8.0g / 10min, Density: 0.904g / cm³ 3 PE11: Linear low-density polyethylene, MFR (190℃, 2.16kg): 14.0g / 10min, Density: 0.911g / cm³ 3

[0088] [Antistatic agent] AA1: Polymer-type antistatic agent: Acid-modified polyolefin polyether block polymer (manufactured by Sanyo Chemical Industries, Ltd.; "Perestat VH230"), density 1.0 g / cm³ 3 Volume resistivity 3 × 10 7 Ω·cm • AA2: Low molecular weight antistatic agent: Glycerin-fatty acid ester-based antistatic agent

[0089] [Lubricant] LA1: Unsaturated fatty acid amide (erucic acid amide) LA2: Unsaturated fatty acid bisamide (ethylenebisoleamide)

[0090] [Comparative Example 1] Comparative Example 1 is a two-layer polyethylene-based unoriented film in which PE1 is blended as the base layer at 100% by weight and as the sealant layer at 100% by weight, an antistatic agent AA2 is added in an amount of 0.3 parts by weight totaling the entire layer, and a lubricant LA1 is added in an amount of 0.057 parts by weight totaling the entire layer, resulting in a film thickness of 50 μm and a sealant layer thickness of 6.0 μm.

[0091] [Prototype Example 1] Prototype Example 1 is a two-layer polyethylene-based unoriented film with a film thickness of 50 μm and a sealant layer thickness of 6.0 μm. It is formulated with 100% by weight of PE1 as the base layer, 92.5% by weight of PE1 and 7.5% by weight of the antistatic agent AA1 as the sealant layer, and LA1 added as a lubricant in an amount equivalent to 0.057 parts by weight of the total layer.

[0092] [Prototype Example 2] Prototype Example 2 is a two-layer polyethylene-based unoriented film that is identical to Prototype Example 1, with the following modifications: PE1 is blended as a sealant layer at 90.0% by weight and the antistatic agent AA1 at 10.0% by weight; LA1 is added as a lubricant at 0.069 parts by weight and LA2 at 0.024 parts by weight (based on the total layer amount); and all other modifications are the same.

[0093] [Prototype Example 3] Prototype Example 3 is a two-layer polyethylene-based unoriented film that is identical to Prototype Example 2, except that it contains 73.9% by weight of PE1 as a sealant layer and 26.1% by weight of AA1 as an antistatic agent.

[0094] [Prototype Example 4] Prototype Example 4 is a two-layer polyethylene-based unoriented film that is identical to Prototype Example 2, except that it is formulated with 65.1% by weight of PE1 as a sealant layer and 34.9% by weight of the antistatic agent AA1.

[0095] [Prototype Example 5] Prototype Example 5 is a two-layer polyethylene-based unoriented film that is identical to Prototype Example 2 except that the sealant layer thickness is 1.5 μm.

[0096] [Prototype Example 6] Prototype Example 6 is a two-layer polyethylene-based unoriented film that is identical to Prototype Example 2 except that the sealant layer thickness is 4.0 μm.

[0097] [Prototype Example 7] Prototype Example 7 is a three-layer polyethylene-based unoriented film in which PE5 is blended as the surface layer at 100% by weight, PE1 as the base layer at 100% by weight, and PE1 is blended as the sealant layer at 90.0% by weight and the antistatic agent AA1 at 10.0% by weight. The film thickness is 50 μm, the sealant layer thickness is 6.0 μm, and the ratio of the thicknesses of the surface layer to the base layer (layer ratio) is 1:3.

[0098] [Prototype Example 8] Prototype Example 8 is a three-layer polyethylene-based unoriented film, which is identical to Prototype Example 7 except that LA1 is added as a lubricant to a total amount of 0.057 parts by weight.

[0099] [Prototype Example 9] Prototype Example 9 is a three-layer polyethylene-based unoriented film, which is identical to Prototype Example 7 except that LA1 is added as a lubricant to a total amount of 0.075 parts by weight.

[0100] [Prototype Example 10] Prototype 10 is a three-layer polyethylene-based unoriented film that is identical to Prototype 7 except that LA1 is added as a lubricant in an amount equivalent to 0.015 parts by weight of the total layer and LA2 is added in an amount equivalent to 0.024 parts by weight of the total layer.

[0101] [Prototype Example 11] Prototype Example 11 is a three-layer polyethylene-based unoriented film that is identical to Prototype Example 10 except that LA1 is added as a lubricant in an amount equivalent to 0.030 parts by weight of the total layer and LA2 is added in an amount equivalent to 0.048 parts by weight of the total layer.

[0102] [Prototype Example 12] Prototype 12 is a three-layer polyethylene-based unoriented film that is identical to Prototype 10 except that LA1 is added as a lubricant at a total weight of 0.019 parts by weight and LA2 is added at a total weight of 0.012 parts by weight, with all other properties remaining the same.

[0103] [Prototype Example 13] Prototype 13 is a three-layer polyethylene-based unoriented film, which is the same as prototype 12 except that the amount of lubricant LA1 has been changed to 0.035 parts by weight for the entire layer.

[0104] [Prototype Example 14] Prototype 14 is a three-layer polyethylene-based unoriented film, modified from prototype 12 by changing the amount of lubricant LA1 to 0.069 parts by weight for the entire layer, while keeping everything else the same.

[0105] [Prototype Example 15] Prototype 15 is a three-layer polyethylene-based unoriented film, which is the same as prototype 12 except that the amount of lubricant LA1 has been changed to 0.100 parts by weight for the entire layer.

[0106] [Prototype Example 16] Prototype 16 is a three-layer polyethylene-based unoriented film, which is the same as prototype 12 except that the amount of lubricant LA1 has been changed to 0.200 parts by weight for the entire layer.

[0107] [Prototype Example 17] Prototype 17 is a three-layer polyethylene-based unoriented film, which is the same as prototype 14 except that the amount of lubricant LA2 has been changed to 0.008 parts by weight for the entire layer.

[0108] [Prototype Example 18] Prototype 18 is a three-layer polyethylene-based unoriented film, which is the same as prototype 14 except that the amount of lubricant LA2 has been changed to 0.038 parts by weight for the entire layer.

[0109] [Prototype Example 19] Prototype 19 is a three-layer polyethylene-based unoriented film, which is the same as prototype 14 except that the amount of lubricant LA2 has been changed to 0.052 parts by weight for the entire layer.

[0110] [Prototype Example 20] Prototype 20 is a three-layer polyethylene-based unoriented film that is identical to Prototype 10 except that LA1 is added as a lubricant in an amount equivalent to 0.081 parts by weight of the total layer and LA2 is added in an amount equivalent to 0.110 parts by weight of the total layer.

[0111] [Prototype Example 21] Prototype 21 is a three-layer polyethylene-based unoriented film that is identical to Prototype 7, with the following modifications: PE2 is blended as a sealant layer at 90.0% by weight and the antistatic agent AA1 at 10.0% by weight; LA1 is added as a lubricant at 0.069 parts by weight and LA2 at 0.024 parts by weight (based on the total layer amount); and all other components are the same.

[0112] [Prototype Example 22] Prototype 22 is a three-layer polyethylene-based unoriented film, which is identical to prototype 21 except that the sealant layer's PE2 is changed to PE3.

[0113] [Prototype Example 23] Prototype 23 is a three-layer polyethylene-based unoriented film, which is identical to prototype 21 except that the PE2 sealant layer is changed to PE4.

[0114] [Prototype Example 24] Prototype 24 is a three-layer polyethylene-based unoriented film, which is identical to prototype 21 except that the PE2 sealant layer is changed to PE5.

[0115] [Prototype Example 25] Prototype 25 is a three-layer polyethylene-based unoriented film, which is identical to prototype 21 except that the sealant layer's PE2 is changed to PE6.

[0116] [Prototype Example 26] Prototype 26 is a three-layer polyethylene-based unoriented film, which is identical to prototype 21 except that the PE2 sealant layer is changed to PE7.

[0117] [Prototype Example 27] Prototype 27 is a three-layer polyethylene-based unoriented film, which is identical to prototype 21 except that the PE2 sealant layer is changed to PE8.

[0118] [Prototype Example 28] Prototype 28 is a three-layer polyethylene-based unoriented film, which is identical to prototype 21 except that the sealant layer's PE2 is changed to PE9.

[0119] [Prototype Example 29] Prototype 29 is a three-layer polyethylene-based unoriented film, which is identical to prototype 21 except that the PE2 sealant layer is changed to PE10.

[0120] [Prototype Example 30] Prototype 30 is a three-layer polyethylene-based unoriented film, which is identical to prototype 21 except that the PE2 sealant layer is changed to PE11.

[0121] [Table 1]

[0122] [Table 2]

[0123] [Table 3]

[0124] [Table 4]

[0125] [Table 5]

[0126] For the polyethylene-based unoriented films of Prototype Examples 1-30 and Comparative Example 1, the haze, the coefficient of dynamic friction of the film surface, and the surface resistivity of the sealant layer were measured, respectively. Furthermore, film laminates were prepared using the polyethylene-based unoriented films of Prototype Examples 1-30 and Comparative Example 1 according to the procedure described below. For the resulting film laminates of each Prototype and Comparative Example, the coefficient of dynamic friction and the surface resistivity of the sealant layer were measured, respectively. The measurement results for each Prototype and Comparative Example are shown in Tables 6-10 below. For the overall evaluation, a "○ (Good)" result was given if all evaluation items described below received a "○ (Good)" result, while a "× (Unacceptable)" result was given if even one item received a "× (Unacceptable)" result.

[0127] [Hayes] Haze (%) is an indicator of transparency. For the polyethylene-based unoriented films of Prototype Examples 1-30 and Comparative Example 1, the haze was measured using a haze meter (manufactured by Nippon Denshoku Industries Co., Ltd.; "NDH-8000") according to the test method compliant with JIS K 7136 (2000). For the polyethylene-based unoriented films of Prototype Examples 1-30 and Comparative Example 1, a haze value of 8.0% or less was evaluated as "○ (Good)", and a value exceeding 8.0% was evaluated as "× (Unacceptable)".

[0128] [Coefficient of dynamic friction on the film surface] The coefficient of dynamic friction is an indicator of slipperiness. For the polyethylene-based unoriented films of Prototype Examples 1-30 and Comparative Example 1, after aging by storing them at 35°C for 7 days, the coefficient of dynamic friction was measured in accordance with JIS K 7125 (1999) using a friction measuring instrument (Toyo Seiki Seisakusho Co., Ltd.; "FRICTION TESTER TR-2") between corona-treated surfaces (substrate layers: Prototype Examples 1-6, Comparative Example 1, or surface layers: Prototype Examples 7-30) and between uncorona-treated surfaces (sealant layers: Prototype Examples 1-30, Comparative Example 1). The coefficient of dynamic friction was evaluated as "○ (Good)" if it was 0.3 or less, and "× (Unacceptable)" if it exceeded 0.3.

[0129] [Surface resistivity of sealant layer] Surface resistivity (Ω / □) is an indicator of antistatic performance. For the polyethylene-based unoriented films of prototype examples 1-30 and comparative example 1, after aging by storing at 35°C for 7 days, 10cm × 10cm test pieces were cut out, and the surface resistivity of the sealant layer was measured in accordance with JIS K 6911 (2006) using a high-resistivity resistivity meter (manufactured by Nitto Seikou Analytech Co., Ltd.; "MCP-HT800") in an atmosphere of 23°C and 50% RH. The surface resistivity was 1 × 10⁻⁶. 13 If the value is less than Ω / □, it is marked as "○ (Good)", 1 × 10 13 Cases where the value was greater than or equal to Ω / □ were evaluated as "× (unacceptable)". Note that the measured value of the surface resistivity was 1 × 10⁻⁶. 14 If the value exceeded Ω / □, it was indicated as "OR" as being overrange.

[0130] [Fabrication of film laminates] A 15μm thick biaxially oriented nylon film (manufactured by Mitsubishi Chemical Corporation; "Santonil SNR") was used as the base film, and approximately 3g / m² of an adhesive (manufactured by Toyo Morton Co., Ltd.; main component "TM-329", hardener "CAT-26B", solvent "ethyl acetate"), which had been prepared for dry lamination, was applied to the surface of this base film. 2 The adhesive was applied and allowed to dry. Then, the base film was laminated to the base layer (Prototype Examples 1-6, Comparative Example 1) or surface layer (Prototype Examples 7-30) of the polyethylene-based unoriented film to form the laminated film portion. Rollers were then passed through the laminated film to ensure close contact between the polyethylene-based unoriented film and the base film (laminated film portion), thereby producing film laminates corresponding to each of the Prototype Examples 1-30 and Comparative Example 1.

[0131] [Coefficient of dynamic friction on the surface of a laminated film] For the film laminates corresponding to prototype examples 1-30 and comparative example 1, after aging by storage at 40°C for 7 days, the coefficient of dynamic friction between sealant layers was measured using a friction measuring instrument (Toyo Seiki Seisakusho Co., Ltd.; "FRICTION TESTER TR-2") in accordance with JIS K 7125 (1999). The coefficient of dynamic friction was evaluated as "○ (Good)" if it was 0.5 or less, and "× (Unacceptable)" if it exceeded 0.5.

[0132] [Surface resistivity of sealant layer] For the film laminates corresponding to prototype examples 1-30 and comparative example 1, after aging by storage at 40°C for 7 days, 10cm x 10cm test pieces were cut out, and the surface resistivity of the sealant layer was measured in accordance with JIS K 6911 (2006) using a high-resistivity resistivity meter (manufactured by Nitto Seikou Analytech Co., Ltd.; "MCP-HT800") in an atmosphere of 23°C and 50% RH. The surface resistivity was 1 x 10⁻⁶. 13 If the value is less than Ω / □, it is marked as "○ (Good)", 1 × 10 13 Cases where the value was greater than or equal to Ω / □ were evaluated as "× (unacceptable)". Note that the measured value of the surface resistivity was 1 × 10⁻⁶. 14 If the value exceeded Ω / □, it was indicated as "OR" as being overrange.

[0133] [Table 6]

[0134] [Table 7]

[0135] [Table 8]

[0136] [Table 9]

[0137] [Table 10]

[0138] [Results and Discussion] Comparative Example 1 is a two-layer polyethylene-based unoriented film using a low-molecular-weight antistatic agent as the antistatic agent and an unsaturated fatty acid amide as the lubricant. As shown in Table 6, Comparative Example 1 consistently showed good antistatic performance and lubricity in the film alone, but both antistatic performance and lubricity deteriorated in the film laminate produced by dry lamination. This is thought to be because the low-molecular-weight antistatic agent is a bleed-out type antistatic agent, and dry lamination caused the low-molecular-weight antistatic agent and the unsaturated fatty acid amide to be adsorbed by the adhesive, resulting in a decrease in antistatic performance and lubricity.

[0139] Prototypes 1-3 are two-layer polyethylene-based unoriented films in which a polymer-type antistatic agent capable of providing semi-permanent antistatic properties was used as an antistatic agent, and the amount of the agent was adjusted. In particular, Prototype 1 used an unsaturated fatty acid amide as a lubricant, while Prototypes 2 and 3 used both an unsaturated fatty acid amide and an unsaturated fatty acid bisamide as lubricants. As a result, as shown in Table 6, in Prototype 1, the antistatic performance of the film alone was insufficient, and both the antistatic performance and lubricity of the film laminate were insufficient. On the other hand, in Prototypes 2 and 3, both the film alone and the film laminate exhibited good antistatic performance and lubricity.

[0140] In prototype example 1, since the lubricant was only an unsaturated fatty acid amide, similar to comparative example 1, it is thought that the slipperiness decreased after dry lamination. In contrast, in prototype examples 2 and 3, since both an unsaturated fatty acid amide and an unsaturated fatty acid bisamide were used as lubricants, appropriate slipperiness was obtained both after film formation (film alone) and after dry lamination (film laminate). This is thought to be because the relatively fast bleed rate of the unsaturated fatty acid amide, which has a small molecular weight, imparted slipperiness after film formation, while the relatively slow bleed rate of the unsaturated fatty acid bisamide, which has a relatively large molecular weight, imparted slipperiness after dry lamination.

[0141] Furthermore, in Prototype Example 1, the amount of polymer-type antistatic agent was small compared to Prototype Examples 2 and 3, which is thought to have resulted in insufficient antistatic performance for both the film alone and the film laminate. Prototype Example 4 is an example of a product containing a large amount of polymer-type antistatic agent, but in Prototype Example 4, it was not possible to form a film due to thickness defects. Therefore, it is considered preferable to blend the polymer-type antistatic agent at a concentration of approximately 10 to 30% by weight.

[0142] The films in prototype examples 5 and 6 are examples in which the sealant layer was formed thinner than in prototype example 2. In prototype example 5, where the sealant layer was thinner, the antistatic performance deteriorated in both the film alone and the film laminate, whereas in prototype example 6, where the sealant layer was thicker than in prototype example 5, the film performance was good. From this, it can be concluded that good antistatic performance can be obtained if the thickness of the sealant layer is about 2 μm or more.

[0143] Examples 7-20 shown in Tables 7 and 8 are three-layer polyethylene-based unoriented films with adjusted lubricant composition and formulation. Example 7 contained no lubricant, and all of them exhibited insufficient lubricity. Examples 8 and 9 are examples where only unsaturated fatty acid amide was used as the lubricant, and its content was adjusted. In Example 8, both the film alone and the film laminate exhibited insufficient lubricity on the sealant layer side. In Example 9, where the content of unsaturated fatty acid amide was increased, the lubricity on the sealant layer side of the film alone improved, but the lubricity on the sealant layer side of the film laminate did not improve.

[0144] Examples 10-20 show cases where the lubricant content was adjusted using unsaturated fatty acid amide and unsaturated fatty acid bisamide. In examples 13-16 and 18-20, it was possible to appropriately balance antistatic performance and lubricity in both the film alone and the film laminate. On the other hand, in examples 10 and 11, the lubricity on the treated surface side (surface layer side) of the film alone was insufficient, in example 12, the lubricity on both the treated surface side (surface layer side) and the sealant layer side of the film alone was insufficient, and in example 17, the lubricity on the sealant layer side of the film laminate was insufficient. From examples 10-20, it is considered that the preferred amount of unsaturated fatty acid amide is 0.035 parts by weight or more on a total layer basis, and the preferred amount of unsaturated fatty acid bisamide is 0.012 parts by weight or more on a total layer basis.

[0145] Examples 21-30 shown in Tables 9 and 10 are three-layer polyethylene-based unoriented films with a modified polyethylene-based resin (linear low-density polyethylene) for the antistatic resin composition constituting the sealant layer. Examples 26, 27, 29, and 30 exhibited high haze and insufficient transparency. On the other hand, good transparency was obtained in Examples 21-25 and 28. From Examples 21-30, it was found that for the polyethylene-based resin (linear low-density polyethylene) of the antistatic resin composition, the preferred MFR (190°C, 2.16 kg load) is approximately 1-6 g / 10 min, and the preferred density is 0.860-0.935 g / cm³. 3 It is thought to be to that extent.

[0146] As described above, in the polyethylene-based unoriented film for dry lamination, by using a sealant layer consisting of an antistatic resin composition containing an appropriate amount of polymer-type antistatic agent with a thickness of 2 μm or more, and using an appropriate amount of unsaturated fatty acid amide and unsaturated fatty acid bisamide as a lubricant, it was possible to achieve both appropriate semi-permanent antistatic properties and lubricity not only in the film itself but also after dry lamination. [Industrial applicability]

[0147] The polyethylene-based unoriented film of the present invention can continuously achieve both antistatic properties and slipperiness, and can appropriately maintain semi-permanent antistatic properties and slipperiness even after dry lamination, making it suitable as a sealant film for dry lamination. Furthermore, a film laminate using the polyethylene-based unoriented film of the present invention is promising as a replacement for conventional film laminates because it appropriately maintains both semi-permanent antistatic properties and slipperiness. [Explanation of Symbols]

[0148] 1,1A film laminate 10,10A Polyethylene-based unoriented film 20 Base material layer 30 sealant layer 40 Surface layer 50 Laminated film portion

Claims

1. A polyethylene-based unoriented film for dry lamination comprising at least two layers, including a base layer mainly composed of polyethylene resin and a sealant layer, The aforementioned substrate layer is made of a resin material mainly composed of linear low-density polyethylene. The sealant layer is a layer with a thickness of 2 μm or more, made of an antistatic resin composition containing 70 to 90% by weight of linear low-density polyethylene and 10 to 30% by weight of a polymer-type antistatic agent. The aforementioned polymeric antistatic agent is a copolymer of a hydrophilic polymer and a modified polyolefin, with a volume resistivity of 1 × 10⁻⁶ ５ ~1 x 10 １１ It is an acid-modified polyolefin polyether block polymer with Ω·cm, When the total amount of each resin material constituting the polyethylene-based unoriented film is 100 parts by weight, the total amount of unsaturated fatty acid amide on a layer-by-layer basis is 0.035 parts by weight or more, and the total amount of unsaturated fatty acid bisamide on a layer-by-layer basis is 0.012 parts by weight or more. A polyethylene-based unstretched film characterized by the following features.

2. The melt flow rate (at 190°C, 2.16 kg load) of the linear low-density polyethylene in the antistatic resin composition is 1 to 6 g / 10 min and the density is 0.860 to 0.935 g / cm³. ３ The polyethylene-based unstretched film according to claim 1.

3. The polyethylene-based unoriented film according to claim 1 or 2, wherein the haze of the polyethylene-based unoriented film is 8% or less.

4. The surface resistivity of the sealant layer side of the polyethylene-based unstretched film, which has been aged at 35°C for 7 days, is 1 × 10⁻⁶. １３ The polyethylene-based unoriented film according to claim 1 or 2, wherein the coefficient of dynamic friction of each surface on the base material layer side and the sealant layer side is less than Ω / □ and 0.3 or less.

5. The polyethylene-based unstretched film according to claim 1 or 2, wherein a surface layer made of a resin material mainly composed of linear low-density polyethylene is laminated on the side of the base layer opposite to the sealant layer.

6. The polyethylene-based unstretched film according to claim 3, wherein a surface layer made of a resin material mainly composed of linear low-density polyethylene is laminated on the side of the base layer opposite to the sealant layer.

7. The polyethylene-based unstretched film according to claim 4, wherein a surface layer made of a resin material mainly composed of linear low-density polyethylene is laminated on the side of the base layer opposite to the sealant layer.

8. A film laminate characterized in that the substrate layer of the polyethylene-based unoriented film according to claim 1 or 2 is provided with a laminated film portion on the side opposite to the sealant layer side.

9. A film laminate characterized in that the substrate layer of the polyethylene-based unoriented film according to claim 3 is provided with a laminated film portion on the side opposite to the sealant layer side.

10. A film laminate characterized in that the substrate layer of the polyethylene-based unoriented film according to claim 4 is provided with a laminated film portion on the side opposite to the sealant layer side.

11. A film laminate characterized in that the surface layer of the polyethylene-based unoriented film according to claim 5 is provided with a laminated film portion on the side opposite to the substrate layer side.

12. A film laminate characterized in that the surface layer of the polyethylene-based unoriented film according to claim 6 is provided with a laminated film portion on the side opposite to the substrate layer side.

13. A film laminate characterized in that the surface layer of the polyethylene-based unstretched film according to claim 7 is provided with a laminated film portion on the side opposite to the base material layer.

14. The surface resistivity of the sealant layer side of the film laminate after aging at 40°C for 7 days is 1 × 10⁻⁶. １３ The film laminate according to claim 8, wherein the coefficient of dynamic friction of the surface on the sealant layer side is less than Ω / □ and less than or equal to 0.5.

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