TWI797330B - Polypropylene-based composite film and packaging materials using it - Google Patents

Abstract

The present invention provides a polypropylene-based composite film, which has high heat-sealing force at low temperature to high temperature, excellent low-temperature impact resistance and bending whitening resistance, and can reduce the amount of lubricant on the surface of the film even if it is matured at 60°C after lamination. Maintained within an appropriate range, the static friction coefficient of the film surface can achieve the desired value; and the packaging material using it.

A polypropylene-based composite film, characterized in that: it contains at least two layers of A layer/B layer, and the A layer is a propylene-based random film with a melt flow rate of 230°C of 2-10g/10 minutes and a melting point of 130-150°C. Copolymer is the main component, and layer B is the ratio of the intrinsic viscosity [η]Cxs of the soluble portion to the intrinsic viscosity [η]Cxis of the insoluble portion relative to xylene at 20°C ([η]Cxs/[η]Cxis) Propylene above 1.6. 100 parts by weight of ethylene block copolymer (a), blended with a resin composition of 10 to 90 parts by weight of low-density polyethylene polymer (b) as the main component, layer A contains 200 to 2000 ppm of fatty acid amide lubricant, Layer B contains 500~5000ppm of fatty acid amide lubricant.

Description

Polypropylene-based composite film and packaging materials using it

The present invention relates to a polypropylene-based composite film, which has high heat-sealing strength from low temperature, has slipperiness, low-temperature impact resistance, and bending whitening resistance; and a packaging material using the same.

It is well known that polypropylene-based films are used as packaging films. In addition, it is known to combine polypropylene-based films with polyethylene terephthalate (PET) films or nylon (Ny) films, especially stretched PET films or A packaging material made by laminating stretched nylon film (ONy) and aluminum foil.

Generally, organic lubricants are added to polypropylene-based films used in packaging films. After film formation, the lubricants will seep out of the film surface and exhibit good slipperiness. Conventional polypropylene-based films are bonded to stretched PET films, ONy films, aluminum foil, etc. through an adhesive, and if the adhesive is cured at a temperature above a certain level, the organic lubricant ( In particular, fatty acid amide-based lubricants) tend to be re-transferred into the film, so slipperiness tends to deteriorate.

For retort applications, after bonding with stretched PET film or ONy film, dusting is performed to maintain slipperiness. However, if the amount of lubricant used for dusting is too large, there will be health and hygiene problems.

In addition, it may not be satisfactorily used in battery packaging materials that require slipperiness in drawing molding. The polypropylene film is laminated with other films to form a laminate. When aged at 60°C or higher, the surface of the film has good slipperiness, especially a static coefficient of friction of less than a certain level, for example, a static coefficient of friction of less than 0.3.

In response to such expectations, Patent Document 1 discloses a laminated film containing 0.02 to 0.2% by weight of unsaturated fatty acid amide with a melting point of 70 to 90°C and 0.01 to 0.12% of unsaturated fatty acid bisamide with a melting point of 115 to 135°C. % by weight, however due to the use of ethylene. α-Olefins have poor heat resistance. When this knowledge is applied to polypropylene, it is necessary to increase the amount of unsaturated fatty acid amide and unsaturated fatty acid bisamide. Although the coefficient of friction is lowered, the surface of the film after aging treatment If the amount of lubricant becomes too much, deposits will appear on the rollers, etc., and there will be problems in the working environment.

In addition, Patent Document 2 discloses a polypropylene-based multilayer film and composite film with a three-layer structure, in which a lubricant such as erucamide with an optimum aging temperature of less than 40°C is added to the two outer layers, and behenamide is added to the middle layer. , Ethylene bisamide and other lubricants with an optimum aging temperature above 40°C, as described in the examples, propylene is used for the middle layer. Ethylene random copolymer with at least one outer layer of propylene. Ethylene random copolymer. In each example of this patent document 2, when a special lubricant is added to each layer, although the static friction coefficient of the surfaces of the laminated films after aging is found to be 0.3 or less, as will be described later, according to the present inventors And so on, both the middle layer and the surface layer are made of acrylic. In the case of ethylene random copolymers, it is difficult to balance high heat seal strength at low temperature to high temperature with low temperature shock resistance, slipperiness, and insulation. Also known is the use of propylene from Patent Document 3. Ethylene block copolymers are used as raw materials for films, but it is difficult to balance high heat seal strength at low temperature to high temperature with low temperature impact resistance, bending whitening resistance, slipperiness, and insulation properties.

In this way, when polypropylene-based films are used as packaging films, in addition to the above-mentioned heat-sealability, properties such as bending whitening resistance, low-temperature shock resistance, and slipperiness are required to be high-level and well-balanced. , excellent, but the previous films may not be able to meet the high requirements in recent years. Especially in recent years, with regard to low-temperature shock resistance, bag breaking strength under severe conditions that will not break even if the bag is repeatedly dropped from a high position with the contents in it (especially in retort However, it has not been seen to use the bag breaking strength under such severe conditions as the evaluation criterion to design low-temperature shock-resistant polypropylene films.

[Prior Art Literature] [Patent Document]

[Patent Document 1] Japanese Patent Application Laid-Open No. 9-77881

[Patent Document 2] Japanese Patent Application Laid-Open No. 11-334004

[Patent Document 3] Japanese Patent Application Laid-Open No. 10-87744

Therefore, the object of the present invention is to provide a polypropylene-based composite film that has high heat-sealing force at low to high temperatures, excellent low-temperature impact resistance and bending whitening resistance, and can be cured at 60°C after lamination. The amount of lubricant on the surface of the film is maintained within an appropriate range, and the coefficient of static friction on the surface of the film can reach the desired value; and the packaging material using it.

In order to solve the above-mentioned problems, the polypropylene-based composite film of the present invention has the following configurations.

A polypropylene-based composite film is characterized in that: it contains at least two layers of A layer/B layer, and the A layer is a propylene-based random film with a melt flow rate of 230°C of 2-10g/10 minutes and a melting point of 130-150°C. Copolymer is the main component, and layer B is the ratio of the intrinsic viscosity [η]Cxs of the soluble portion to the intrinsic viscosity [η]Cxis of the insoluble portion relative to xylene at 20°C ([η]Cxs/[η]Cxis) Propylene above 1.6. 100 parts by weight of ethylene block copolymer (a), blended with a resin composition of 10 to 90 parts by weight of low-density polyethylene polymer (b) as the main component, layer A contains 200 to 2000 ppm of fatty acid amide lubricant, Layer B contains 500~5000ppm of fatty acid amide lubricant.

A kind of laminated body, it is on the opposite surface layer of the A side of the above-mentioned polypropylene composite film A layer selected from biaxially stretched polyethylene terephthalate film, biaxially stretched polypropylene film, biaxially stretched nylon At least one of the group consisting of film and aluminum foil.

A battery packaging material using the laminate described above.

A retort packaging material using the laminate described above.

According to the present invention, the amount of lubricant on the surface of the film at normal temperature (23°C) can be maintained within an appropriate range, and the amount of lubricant on the surface of the film can be maintained within an appropriate range even when it is aged at 60°C. The static friction coefficient of the film surface can be suppressed to 0.3 or less, and it is suitable for polypropylene-based composite films for battery packaging materials that require slipperiness, and packaging materials equipped with them.

In addition, in view of the requirements for bag breaking strength especially for retort packaging materials under severe conditions, the present invention can meet this requirement, and can also satisfy heat sealability or low-temperature shock resistance with good balance, so it can realize Polypropylene-based composite films for packaging materials, and packaging materials equipped with them.

The polypropylene-based composite film of the present invention includes at least two layers of A layer and B layer, and the A layer is mainly composed of a propylene-based random copolymer. It is configured to configure the B layer on one side of the A layer, and the B layer contains propylene. An ethylene block copolymer (a) and a low-density polyethylene resin (b), and even ideally, a block copolymer having a styrene block or a block copolymer having a crystalline olefin block as The polymer (c) more desirably contains a propylene-based random copolymer (d).

Layer A of the polypropylene-based composite film of the present invention is mainly composed of a propylene-based random copolymer having a melt flow rate (hereinafter abbreviated as MFR) of 2-10 g/10 minutes at 230°C and a melting point of 130-150°C. In the present invention, the main component of layer A refers to a component exceeding 50% by weight in layer A. When the propylene-based random copolymer is 50% by weight or less, the heat-sealing strength at 130°C and 160°C decreases.

In addition, when the MFR of the propylene-based random copolymer of the above-mentioned A layer at 230°C is less than 2 g/10 minutes, the uniform buildability of the B layer will deteriorate, and the low-temperature heat-sealing strength at 130°C will decrease. 10g/10 minutes, the exudation of the lubricant will be deteriorated, and the slipperiness will be reduced.

The above-mentioned propylene-based random copolymer of layer A refers to a copolymer of propylene and at least one α-olefin. Examples of α-olefin include ethylene, butene, octene, etc. From the perspective of slipperiness and heat sealability Come, propylene, which is a copolymer of ethylene. Ethylene random copolymers are preferred.

The layer A of the polypropylene-based composite film of the present invention is mainly composed of the above-mentioned propylene-based random copolymer, and preferably contains 200-2000 ppm of a fatty acid amide-based lubricant. When the fatty acid amide-based lubricant content is less than 200ppm, the slipperiness will be deteriorated. If it exceeds 2000ppm, heat dissipation will increase during melt extrusion, causing contamination in the process and deteriorating film-forming properties. In addition, at 130ppm The low temperature heat seal strength at ℃ will decrease.

Suitable fatty acid amide lubricants can include, for example, oleic acid amide, erucic acid amide, stearic acid amide, palmitic acid amide, behenyl amide, etc., especially from the polypropylene composite film of the present invention In terms of dispersibility and slipperiness in the resin composition used, erucamide is suitable.

In addition, if 300 to 5000 ppm of inorganic or organic particles are added to the above-mentioned layer A in the range that does not hinder the heat sealability, even if the content of the fatty acid amide lubricant is reduced, the slipperiness will be improved. When the polypropylene-based composite film is rolled into a long strip, defects due to wrinkles or poor degassing are reduced, which is preferable. When the content is 300 ppm or less, the effect of imparting slipperiness is not observed, and when it exceeds 5000 ppm, the heat-sealability will decrease.

As for the inorganic particles, silicon dioxide, zeolite, calcium carbonate, etc. are preferably mentioned, and suitable organic particles include cross-linked PS, cross-linked PMMA, and the like. These average particle diameters are preferably in the range of 1-5 μm. When the average particle size is less than 1 μm, the addition effect is not observed, and when it exceeds 5 μm, the heat-sealing force will decrease.

The B layer of the polypropylene-based composite film of the present invention is based on the ratio ([η]Cxs/[η]Cxs of the soluble portion containing 20°C xylene to the intrinsic viscosity [η]Cxs of the insoluble portion ] Cxis) 1.6 or more propylene. The resin composition of an ethylene block copolymer (a) and a low-density polyethylene polymer (b) is a main component. In the present invention, the above-mentioned main component in the B layer refers to a component exceeding 50% by weight in the B layer.

The propylene of the B layer of the polypropylene-based composite film of the present invention. In the ethylene block copolymer (a), the ratio ([η]Cxs/[η]Cxis) of the intrinsic viscosity [η]Cxs of the soluble portion of xylene at 20°C to the intrinsic viscosity [η]Cxis of the insoluble portion is 1.6 Above, preferably in the range of 1.6~2.0. When [η]Cxs/[η]Cxis is less than 1.6, when the film is heat-sealed above 160°C, the film will be thinned due to crushing, and the heat-sealing strength will decrease, or the heat-sealing or stretching process will cause Pressure, leakage of resin occurs, and pollution of packaging material manufacturing steps occurs. In addition, if [η]Cxs/[η]Cxis exceeds 2.0, small colloidal defects will appear in the film and become film protrusions. When laminating with other substrates, air will be involved in the interface, and the lamination strength will decrease. In addition, There are cases where the heat seal strength is lowered and the content leaks.

In addition, the propylene in the B layer. In the ethylene block copolymer (a), the ratio of the 20°C xylene insoluble portion representing the proportion of the polypropylene portion is preferably 70 to 85% by weight, and the intrinsic viscosity [η]Cxis of the xylene insoluble portion is preferably 1.5 to 2.0 dl/g stands for ethylene. The intrinsic viscosity [η]Cxs of the 20°C xylene soluble portion of the ratio of the propylene copolymerized rubber component is preferably 2.4 to 4.0 dl/g. When the intrinsic viscosity [η]Cxis of the xylene insoluble part is less than 1.5, the film will be crushed and thinned during heat sealing or stretching, and if it exceeds 2.0dl/g, the film will become too hard. Drawing formability deteriorated. In addition, when the intrinsic viscosity [η]Cxs of the xylene soluble part is less than 2.4dl/g, the sealing strength will decrease, and if it exceeds 4.0dl/g, the particle size of the rubber component will be very large, and the sea-island structure interface of the film will Cracks will occur, and low temperature shock resistance or heat sealability will decrease.

Here, the above-mentioned 20 ℃ xylene insoluble portion and soluble portion refers to the above-mentioned propylene. After the pellets of ethylene block copolymers are completely dissolved in boiling xylene, the temperature is lowered to 20°C, left for more than 4 hours, and then filtered into precipitates and solutions, the precipitates are called 20°C xylene As for the insoluble part, the solution part (filtrate) was dried and solidified, and the part obtained by drying at 70 degreeC under reduced pressure was called the xylene soluble part.

The above-mentioned propylene. In the ethylene block copolymer, the method of adjusting the intrinsic viscosity of the xylene-insoluble part and the soluble part, and the melt flow rate can be listed in the above-mentioned propylene. A method of adding a molecular weight modifier such as hydrogen or a metal compound in each step of the polymerization of an ethylene block copolymer; a method of melting and kneading the obtained powdery polymer and adding additives during granulation; A method of melt-kneading a powdery polymer and adjusting the kneading conditions during granulation, etc.

In addition, the propylene used in the present invention. The method for producing the ethylene block copolymer includes a method of polymerizing propylene or ethylene as a raw material using a catalyst. As the catalyst here, a Ziegler-Natta type catalyst or a metallocene catalyst or the like can be used, for example, catalysts listed in JP-A-07-216017 are suitably used.

Specifically, in the presence of an organosilicon compound and an ester compound having a Si-O bond by (1), by the general formula Ti(OR) _a X _4-a (wherein, R is a carbon number of 1 A hydrocarbon group of ~20, X is a halogen atom, and a satisfies 0<a≦4, preferably 2≦a≦4, especially a=4). The titanium compound represented by the organic magnesium compound is reduced, and the obtained solid is formed Objects are treated with ester compounds. Then, treat with the mixture of ether compound and titanium tetrachloride, or the mixture of ether compound, titanium tetrachloride and ester compound, the obtained solid catalyst containing trivalent titanium compound, (2) organoaluminum compound, (3) A catalyst system formed of an electron-donating compound (preferably dialkyldimethoxysilane, etc.).

The method for producing the copolymer (a) is to polymerize a polymer part mainly composed of propylene in the first step in the absence of an inert agent substantially from the viewpoint of productivity and low-temperature shock resistance, and then In the second step, ethylene is polymerized in the gas phase. The method of propylene copolymer part is preferred.

Here, the polymer part mainly composed of propylene is preferably a propylene homopolymer having a melting point of 160°C or higher from the viewpoint of heat resistance and rigidity, and propylene may be used as long as the melting point is in the range of 160°C or higher. Copolymers of α-olefins with a small amount of ethylene, 1-butene, etc.

The B layer in the polypropylene-based composite film of the present invention is the above-mentioned propylene. The ethylene block copolymer (a) is blended with a low-density polyethylene-based polymer (b). According to the knowledge of the inventors of the present invention, the polypropylene composite film of the present invention, for example, when cracking (whitening) occurs at the interface of the sea-island structure of the film during the deformation of the drawing process for battery exterior applications, there will be content Concerns about leakage of the electrolyte of the material. Therefore, it must be designed to make propylene. In the ethylene block copolymer, the dispersion of the rubber component that is the island portion is extremely small, and the dispersion can be made extremely small by containing a low-density polyethylene-based polymer.

In addition, by blending low-density polyethylene polymer (b), the glass transition point is lower than that of propylene. The composition of ethylene block copolymer can improve low-temperature shock resistance and bending whitening resistance. In addition, the rubber component can be evenly and finely dispersed in the B layer, and when used as a cooking packaging material, it can inhibit the oiliness of the content. Occurrence of unevenness (orange peel) due to film swelling due to food (improved resistance to orange peel). As mentioned above, the low-density polyethylene resin (b) preferably includes low-density polyethylene, linear low-density polyethylene, etc., linear low-density polyethylene, due to propylene. The rubber component in the ethylene block copolymer is preferable because it has a high dispersion effect and good bending whitening resistance or orange peel resistance.

When the density of linear low-density polyethylene is in the range of 0.900~0.935g/cm ³ and the MFR is in the range of 0.5~20g/10min, in propylene. Good dispersion in ethylene block copolymers, propylene. The ethylene block copolymer is preferable because it has a high dispersion effect of the rubber component.

The method for producing linear low-density polyethylene is not particularly limited, and a conventional Ziegler-Natta catalyst or a product produced using a metallocene catalyst can be used.

In addition, the above-mentioned propylene. Ethylene block copolymers can contain 5-30% by weight of elastomers to the extent that they do not hinder the necessary physical properties. The elastomeric system is produced by combining catalyst technology and polymerization process technology to achieve high rubber content. Performance vinyl or styrene elastomers. In this manner, similar to low-density polyethylene-based polymers, the dispersion of sea-island structures can be reduced.

The B layer in the polypropylene-based composite film of the present invention is based on the above-mentioned propylene. 100 parts by weight of an ethylene block copolymer (a) and a resin composition in which 15 to 90 parts by weight of the above-mentioned low-density polyethylene-based polymer (b) are blended as a main component.

relative to propylene. When the ethylene block copolymer (a) is 100 parts by weight and the above-mentioned low-density polyethylene-based polymer (b) is less than 15 parts by weight, for example, when it is used as a packaging material for batteries, it will crack during drawing and molding, resulting in Whitening, and there is a concern that the electrolyte solution of the contents may leak. In addition, when it is used as a packaging material for oily food for retort purposes, the orange peel becomes severe and poor appearance occurs.

If relative to propylene. Ethylene block copolymer (a) 100 parts by weight, the above-mentioned low-density polyethylene polymer (b) exceeds 90 parts by weight, then the lubricant transferred to the film surface will be reduced, and the slipperiness will be poor. In addition, low temperature shock resistance Sex will decrease. In addition, dispersibility deteriorates, streaky defects occur during melt extrusion, and film formability deteriorates.

In the polypropylene-based composite film of the present invention, by setting the fatty acid amide-based lubricant content in the B layer to 500-5000 ppm, it can be cured at 60°C or higher to harden the adhesive after lamination with other materials. The fatty acid amide lubricant in the B layer is transferred to the surface of the B layer, and further transferred to the A layer from here. As a result, when aging at 60°C or higher, the lubricant contained in layer A is transferred in layer A, and the lubricant transferred from layer B to layer A is properly balanced compared to the lubricant contained in layer A. As a result, the slipperiness after lamination For the surface of the film that is regarded as a problem, the amount of lubricant should be in the most suitable range. For example, the amount of fatty acid amide-based lubricant exuded from the film surface after aging at 60°C for 3 days can be maintained at 3~20mg/m ² , preferably In the range of 5~15mg/m ² , the static friction coefficient between the surfaces of layer A can reach below 0.3.

In addition, in the B layer, by relative to the aforementioned propylene. 100 parts by weight of the ethylene block copolymer (a) and 10 to 90 parts by weight of the aforementioned low-density polyethylene polymer (b) are blended with a block copolymer having a styrene-based block or a block copolymer having a crystalline olefin block. Segment copolymer polymer (c) composed of 5~20 parts by weight of resin, can make propylene. The dispersion of the rubber component in the island portion in the ethylene block copolymer is smaller.

The block copolymer having a styrenic block or the block copolymer having a crystalline olefin block as the polymer (c) refers to a block copolymer (c1) having a styrenic block, or A block copolymer (c2) having a crystalline olefin block. The block copolymer (c1) having a styrenic block used in the present invention includes, for example, compounds proposed in JP-A-3-128957. Specifically, it is composed of a polymer block of a styrene-based monomer (c3) and a conjugated diene-based monomer (c4). The styrene-based monomer (c3) is not particularly limited, and specific examples include styrene, α-methylstyrene, p-methylstyrene, etc. Among them, styrene and α-methylstyrene are Preferably, styrene is particularly preferred from the viewpoint of polymerizability.

Conjugated diene monomers (c4) include, for example, 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-pentadiene, 2-methyl-1, 3-pentadiene, 1,3-hexadiene, 4,5-diethyl-1,3-octadiene, 3-butyl-1,3-octadiene, chloroprene, etc. Among them, the polybutadiene block is superior in rubber elasticity exhibited by the polymer block, and can impart excellent impact resistance to the finally obtained polypropylene-based composite film of the present invention. Section is better.

This block copolymer (c1) having a styrenic block is particularly suitable for use as a commercial product, such as styrene. Ethylene Butene. Styrene triblock copolymer (hereinafter abbreviated as SEBS). The ethylene butene block part is easy to be compatible with polypropylene resin, improving propylene. The compatibility effect of the ethylene block copolymer (a) is high. The content of the polystyrene block in SEBS is preferably 12 to 67% by weight. When the content of the polystyrene block is at least 12% by weight, the blocking resistance is good, and when it is at most 67% by weight, the low-temperature shock resistance becomes good. In addition, the MFR at 230°C is preferably 0.5~10g/10min. If the MFR is at least 0.5 g/10 minutes, the dispersibility of the mixed resin is good, and if the MFR is at most 10 g/10 minutes, the low-temperature shock resistance is good.

The block copolymer (c2) having a crystalline olefin block used in the present invention is a copolymer having a block (c5) composed of a crystalline polyolefin and another block (c6) not having crystallinity , preferably has a block formed of a conjugated diene polymer as the other block (c6).

Such a block copolymer (c2) having a crystalline olefin block includes, for example, compounds proposed in JP-A-3-128957. Specifically, it is possible to synthesize a polybutadiene polymer block with a low 1,2-vinyl bond content (for example, 25% or less) and a conjugated diene compound as the main body with 1,2- and 3,4-bond content rate of high (for example, 50% or more) polymer block formed copolymer, and make it hydrogenated, so that the polybutadiene part into a structure similar to polyethylene, and produced Crystalline polymer blocks, etc.

Examples of the aforementioned conjugated diene compounds include 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-pentadiene, 2-methyl-1,3 -Pentadiene, 1,3-hexadiene, 4,5-diethyl-1,3-octadiene, 3-butyl-1,3-octadiene, chloroprene, etc., industrial From the viewpoint of ease of acquisition, it is preferable to use 1,3-butadiene and isoprene. Such block copolymers with crystalline olefin blocks are particularly suitable for commercial use, such as polyethylene. Ethylene Butene. Block copolymers constructed of polyethylene (hereinafter abbreviated as CEBC), the ethylene butene block part is easily compatible with the polypropylene resin, and the polyethylene block part is easily compatible with the polyethylene resin, so the increase in propylene. The compatibility effect of the ethylene block copolymer (a) and the low-density polyethylene polymer (b) is high. The polyethylene block content in CEBC is preferably 15 to 40% by weight. When the polyethylene block content is at least 15% by weight, the blocking resistance is good, and when it is at most 40% by weight, the low-temperature impact resistance is good. In addition, the MFR at 230°C is preferably 0.5~10g/10min. If the MFR is at least 0.5 g/10 minutes, the dispersibility of the mixed resin is good, and if the MFR is at most 10 g/10 minutes, the low-temperature shock resistance is good.

In addition, the B layer by using relative to the aforementioned propylene. 100 parts by weight of ethylene block copolymer (a) and 10 to 90 parts by weight of the aforementioned low-density polyethylene polymer (b) are blended at 230°C with a melt flow rate of 2 to 10 g/10 minutes and a melting point of 130 to 150 A resin composition of 10 to 50 parts by weight of the propylene-based random copolymer (d) at °C is preferable since the interface adhesion force with the layer A described above becomes high, and as a result, the heat-sealing strength becomes high. When the added amount of the propylene-based random copolymer (d) is less than 10 parts by weight, the effect of improving the heat seal strength is not observed, and when it exceeds 50 parts by weight, the low-temperature shock resistance decreases.

Suitable propylene-based random copolymers (d) can be exemplified by random copolymers of α-olefins such as ethylene, butene, and octene, and propylene of ethylene copolymers. Ethylene random copolymers are preferable because they can balance heat-sealing force and slipperiness in a wide range.

When the melting point of the above-mentioned propylene-based random copolymer (d) is less than 130°C, the layer thickness becomes thin due to the temperature and pressure during heat sealing, and when the melting point exceeds 150°C, the low-temperature shock resistance may decrease.

The polypropylene-based composite film of the present invention at least includes a two-layer structure of layer A/layer B, but on the other layer of the layer B of the present invention, the MFR at 230°C is 2~10g/10 minutes, and the melting point is Propylene-based random copolymer at 130~150℃ is the main component, and the C layer contains 200~2000ppm of fatty acid amide lubricant. It is designed as a three-layer laminate of A layer/B layer/C layer. Since the lamination strength becomes high, it is preferable. The reason for this is considered to be that the surface of the film is treated with corona discharge to increase the wetting tension, and when the adhesive is applied and laminated with other substrates, the surface of the C layer is smoother than that of the B layer and the amount of lubricant exudation is lower.

In the polypropylene-based composite film of the present invention, after aging at 23°C for 3 days, the static friction coefficient between the surfaces of the layers A is preferably less than 0.3, more preferably in the range of 0.1-0.3. In addition, the polypropylene-based composite film of the present invention, after aging at 60°C for 3 days, the static friction coefficient between the surfaces of the layers A is preferably less than 0.3, preferably in the range of 0.1-0.3. If the coefficient of static friction between the surfaces of the A layers exceeds 0.3, film cracks will occur during forming for battery packaging materials that require slipperiness during drawing, and the yield of products will deteriorate. When using flat bags, stand-up bags, etc. as packaging materials for food, the opening performance of the bag is poor, and the filling performance of the contents will deteriorate. If the coefficient of static friction between the surfaces of the A layers is less than 0.1, misalignment will occur when bag-made processed products are stacked.

In addition, if the above-mentioned lubricant amount is in the most suitable range, when the surface of layer A is overlapped with the surface of layer B or C, the static friction coefficient will be 0.3 or less, so when the polypropylene-based composite film of the present invention is rolled into a long strip, there will be no wrinkles. Creases and air accumulation are reduced, improving productivity.

When the content of the fatty acid amide lubricant in the B layer is less than 500 ppm, the amount of fatty acid amide lubricant on the surface of the A layer is small, and the static friction coefficient between the surfaces of the A layers exceeds 0.3, and the slipperiness deteriorates. There are cases where it cannot be satisfactorily used for packaging materials for batteries, where slipperiness is required for molding. In addition, if it exceeds 5000ppm, although the coefficient of friction is lowered, the amount of lubricant on the surface of the film becomes too large, and the lubricant adheres to rollers in the film formation or lamination steps, causing problems in the working environment. In addition, during heat sealing, the lubricant will accumulate on the film interface, and the heat sealing strength will decrease.

The thickness of layer A or layer C of the polypropylene-based composite film of the present invention is preferably more than 1 μm, and the total thickness is preferably in the range of 20 to 200 μm.

When the thickness of layer A or layer C is less than 1 μm, sufficient heat-sealing strength cannot be obtained at the above-mentioned 130° C. and 160° C., and a range of 2 to 30 μm is preferable. In addition, when the total thickness is less than 20 μm, sufficient low-temperature shock resistance cannot be obtained, and there is a possibility of leakage of battery electrolyte or steamed food in the contents. Moreover, when the total thickness exceeds 200 micrometers, since lamination processability will fall and manufacturing cost will become high, it is unfavorable.

In addition, the volume resistivity of the polypropylene-based composite film of the present invention is 1×10 ¹¹ ~1×10 ¹⁴ Ω. The range of m is preferable. In the case of battery packaging materials required to have electrical insulation, the volume resistivity is less than 1×10 ¹¹ Ω. m, poor insulation, battery performance will be reduced, if more than 1 × 10 ¹⁴ Ω. m, static electricity will be generated, and lamination processability or battery performance will also be poor.

In order to make the volume resistivity above 1×10 ¹¹ ~1×10 ¹⁴ Ω. The range of m can be achieved by making layers A and C contain fatty acid amide lubricants at 200-2000 ppm, and layer B with fatty acid amide lubricants at 500-5000 ppm.

In the polypropylene-based composite film of the present invention, the heat-sealing strength of the A-layer surfaces at 130°C is 30N/15mm or more, and the heat-sealing strength at 160°C or more is 55N/15mm or more, and the above-mentioned laminate is used as a packaging material. , it is better in terms of content protection.

Packaging materials for retort foods require low-temperature sealability. If the heat seal strength between the surfaces of layer A at 130°C is less than 30N/15mm, the food contents will leak after retort treatment. In addition, if the heat seal strength at 160°C or higher is less than 55N/15mm, when used as a packaging material for batteries, the internal pressure will increase due to heat during charging and discharging, which will cause electrolyte leakage, or when used as a packaging material for retort food. Liquid leaks from the heat seal during the pouch test.

The present invention also provides a packaging bag for battery exterior packaging and a packaging bag for cooking and cooking, which are formed of the above-mentioned laminated body.

Also provide a kind of packing material, be by the opposite side of the A layer in the polypropylene composite film of the present invention laminated and selected from biaxially stretched polyethylene terephthalate film, biaxially stretched polypropylene film, biaxially stretched It is formed by a laminate of more than one kind of stretched nylon film and aluminum foil.

The manufacturing method of the laminated body is suitable to adopt the usual dry lamination method, and the film constituting the laminated body is bonded by using an adhesive. Adhesive polyolefin resin extrusion and lamination method.

The above-mentioned adhesive for dry lamination is not particularly limited. For example, when laminating with a biaxially stretched polyethylene terephthalate film, an adhesive comprising a polyol selected from the group consisting of polyurethane polyols, polyester polyols and A two-component reactive adhesive consisting of a first liquid of one or two or more polyols in a group consisting of polyether polyols and a second liquid (curing agent) containing isocyanate, etc. In addition, when laminating with aluminum foil, for example, adhesives made of polyurethane adhesives, acrylic adhesives, epoxy adhesives, polyolefin adhesives, elastic adhesives, fluorine adhesives, etc. agent layer. In particular, acrylic adhesives and polyolefin adhesives are preferred. When used as battery packaging materials, electrolyte resistance and water vapor shielding properties can be improved.

These laminates use the polypropylene-based composite film of the present invention as a sealing layer, and are processed into packaging materials such as molded sheets, flat bags, and stand-up bags. In addition, the laminated structure of these laminates can be adapted to the required characteristics of packaging materials, such as sealing performance that meets the quality retention period of the packaged food, dimensions that can correspond to the weight of the contents, or low-temperature shock resistance, and electrolyte resistance. Equal and appropriate selection.

[Example]

The present invention will be specifically described below with reference to examples, but the scope of the present invention is not limited thereto. In addition, measurement methods and evaluation methods of various physical property values are disclosed below.

(1) Content of xylene insoluble part and soluble part at 20℃

After completely dissolving 5 g of polypropylene pellets in 500 mL of boiling xylene (grade 1 manufactured by Kanto Chemical Co., Ltd.), the temperature was lowered to 20° C., and left to stand for 4 hours or more. Then, it was filtered into a precipitate and a solution, and separated into a soluble part and an insoluble part. As for the soluble part, the filtrate was dried and solidified, dried under reduced pressure at 70° C., and its weight was measured to obtain the content (% by weight).

(2) Intrinsic viscosity ([η]Cxs, [η]Cxis) of xylene soluble part and insoluble part at 20℃

Using the sample separated into the soluble portion and the insoluble portion by the above (1), measurement was performed in tetralin at 135° C. using an Ubbelohde Viscometer (Ubbelohde Viscometer).

(3) Ethylene content of the copolymer

According to the method described on page 616 of the Polymer Analysis Handbook (published by Kinokuniya Shoten in 1995), it can be determined by infrared spectroscopy.

(4) Melt flow rate (MFR)

According to JIS K7210 (1999), propylene random copolymer and propylene. The ethylene block copolymer was measured at a temperature of 230°C, and the low-density polyethylene polymer was measured at a temperature of 190°C under a load of 21.18N.

(5) The melting point of the resin

Using a differential scanning calorimeter (DSC-60 manufactured by Shimadzu Corporation), the temperature was raised at a rate of 20° C. to 10° C./min. Among the melting peaks when heated to 250° C., the highest peak temperature was the melting point.

(6) Density of the resin

Based on JIS K7112 (1999), it measured by the measuring method using a density gradient tube.

(7) Heat seal strength

In terms of packaging materials for batteries, biaxially stretched PET film (PET-BO) with a thickness of 12 μm, nylon 6 stretched film (ONy) with a thickness of 15 μm, and aluminum foil with a thickness of 40 μm after chemical conversion treatment on both sides, and the polymer of the present invention Layer B or C of the acrylic composite film is laminated with a urethane-based adhesive by the usual dry lamination method and aged at 60°C for 3 days to obtain PET-BO/adhesive/ONy/adhesive/ Laminate (A) of aluminum foil/adhesive/polypropylene-based composite film of the present invention (the outermost layer is the surface of layer A).

In addition, in terms of retort packaging materials, stretched PET film with a thickness of 12 μm, ONy film with a thickness of 15 μm, and the polypropylene-based composite film of the present invention are laminated by a common dry lamination method using a urethane-based adhesive. Matured at 40°C for 3 days to obtain a laminate (B) of PET-BO/adhesive/ONy/adhesive/polypropylene composite film of the present invention (the outermost layer is the surface of layer A).

The evaluation of the battery packaging material is to use the above-mentioned laminate (A) and use a flat heat sealer to overlap the surfaces of the A layer and heat it under the conditions of a sealing temperature of 160°C, a sealing pressure of 0.2 MPa, and a sealing time of 2 seconds. After sealing, it was cut into strips with a width of 15 mm, and the heat-sealing strength was measured by the T-peel method at a tensile speed of 300 mm/min using a universal tensile testing machine manufactured by ORIENTEC. If the heat-sealing strength is more than 55 N/15 mm, it is rated as (◯), and when it is less than 55 N/15 mm, it is rated as (×).

In addition, the evaluation for retort packaging materials is to use the above-mentioned laminate (B), and use a flat heat sealer to overlap the surface of layer A, and seal at a sealing temperature of 130°C and 160°C, a sealing pressure of 0.2MPa, and a sealing time of 1 second. After heat-sealing under certain conditions, cut into strips with a width of 15mm, and after cooking at 130°C for 30 minutes, use a universal tensile testing machine made by ORIENTEC to test the T-peel at a tensile speed of 300mm/min. Determination of heat seal strength. The heat seal strength at 130° C. was rated as (◯) if it was 30 N/15 mm or more, and was rated as (×) if it was less than 30 N/15 mm. Moreover, the heat-sealing strength in 160 degreeC was 55 N/15mm or more and was rated as ((circle)), and was less than 55 N/15mm and was rated as (x).

(8) Low temperature shock resistance

Using the laminate (B) for retort packaging materials produced by the above-mentioned heat seal strength measurement, two sheets of the laminate were used in such a way that the polypropylene-based composite film (surface of layer A) of the present invention became the inner surface of the bag. A CA-450-10 type heat sealer manufactured by Fuji Impulse Co., Ltd. produced a pouch with a heating time of 1.4 seconds, a cooling time of 3.0 seconds, and a bag size of 150 mm×285 mm. This bag was filled with 1 L of saline with a concentration of 0.1% by weight, and then retorted at 135° C. for 30 minutes. After the bags after the retort treatment were stored in the refrigerator at 0° C. for 24 hours, they were dropped from a height of 50 cm to a flat ground (n number 20), and the number of times until the bags broke was recorded. In this evaluation method, the average value of n number of 20 pieces is taken, and the average number of times until the bag is broken is 30 times or more, and the low-temperature shock resistance is judged as good (○), and the low-temperature shock resistance is judged as less than 30 times. (×).

(9) Resistance to orange peel

Using the laminate (B) for retort packaging materials produced by the above-mentioned heat seal strength measurement, the polypropylene-based composite film of the present invention (the surface of layer A) is used as the inner surface of the bag, and sealed at a sealing temperature of 160°C. Two sheets of this laminate were heat-sealed under the conditions of a pressure of 0.2 MPa and a sealing time of 2 seconds to produce a 3-square bag (flat bag, sealing width 5 mm) with a size of 160 mm×210 mm (internal size). After filling the bag with commercially available retort curry (retort curry "KUKURE curry. Xinkou" manufactured by House Food Industry Co., Ltd.), retort at 130°C for 30 minutes, and visually determine the occurrence of irregularities on the surface of the laminate immediately after the treatment. situation. The situation that did not occur at all was rated as grade 1, the situation that occurred slightly was graded as grade 2, the situation that occurred slightly was graded as grade 3, the situation that occurred definitely was graded as grade 4, and the situation that occurred severely was graded as grade 5. In this evaluation method, rank 1 is excellent in orange peel resistance (⊚), rank 2 is good in orange peel resistance (◯), and ranks 4 and 5 are poor in orange peel resistance (×).

(10) Bending and whitening resistance

After retorting the laminate (B) for the above-mentioned retort packaging material at 130°C for 30 minutes, using the MIT bending tester manufactured by Toyo Seiki Seisakusho, under the conditions of a sample width of 10 mm, a bending angle of 135 degrees (approximately), and a load of 5.04 N After bending down 100 times, the state of whitening of the bent portion was visually judged (n number 5). Rank 1 for no bleaching at all, rank 2 for slight bleaching, rank 3 for mild bleaching, and rank 4 for clear bleaching. The situation is rated level 5. According to this evaluation method, the grades 1 and 2 are good in bending whitening resistance (○), and the grades 4 and 5 are poor in bending whitening resistance (×).

(11) Film thickness and thickness composition

The thickness of the film was measured at any 10 points of the film using a dial gauge according to JIS K7130 (1992) A-2 method. The average value was divided by 10 to determine the film thickness.

In the case of a laminated film, the thickness of each layer is obtained by embedding the laminated film in epoxy resin, cutting out a section of the film with a microtome, observing the section with a scanning electron microscope at a magnification of 3,000 times, and calculating the thickness of each layer. thickness.

(12) Static friction coefficient

The polypropylene-based composite film of the present invention is used by overlapping the surfaces of the A layers or the surfaces of the A layer and the B layer or the C layer, and measures according to JIS K7125 (1999).

(13) Volume resistivity

According to JIS K6911 (1995), according to the double ring electrode method (measurement of the resistivity of an insulator of 10 ⁸ ~ 10 ¹⁶ Ω), apply 500V between the electrodes between the circular electrodes, and measure the resistance value after 1 minute. have to.

(14) Processability, drawing formability

Observation of lamination disorder and processing roller contamination in the film-making step of the polypropylene-based composite film of the present invention, or processing roller contamination or wrinkle in the lamination volume layer step for the preparation of the sample for heat seal strength measurement in the above (7) The occurrence of creases, resin bleeding during drawing molding, and the like were evaluated as follows.

◯: No drum contamination, wrinkles, etc. occurred in the film forming step and the laminating step, and a product with good appearance was obtained, and the drawing formability was also good.

×: Drum contamination, wrinkles, etc. occurred in the film forming step and lamination step, and resin bleeds out during drawing molding.

The following items were prepared as resins and lubricants for layers A, B, and C of Examples and Comparative Examples.

(1) Propylene-based random copolymer-1

Propylene with an MFR of 3.3g/10min and a melting point of 142°C. Ethylene Random Copolymer (Denoted "EPC-1").

(2) Propylene-based random copolymer-2

Propylene with an MFR of 6.0g/10min and a melting point of 138°C. Ethylene Random Copolymer (Denoted "EPC-2").

(3) Propylene-based random copolymer-3

Propylene with an MFR of 12.0g/10min and a melting point of 127°C. Ethylene Random Copolymer (Denoted "EPC-3").

(4) Propylene-based random copolymer-4

Propylene with an MFR of 1.5g/10min and a melting point of 132°C. Ethylene Random Copolymer (Denoted "EPC-4").

(5) Propylene-based random copolymer-5

Propylene with an MFR of 5.0g/10min and a melting point of 156°C. Ethylene Random Copolymer (Denoted "EPC-5").

(6) Propylene. Ethylene Block Copolymer-1

The xylene soluble portion at 20°C is 10% by weight, the intrinsic viscosity [η]Cxs of the soluble portion is 3.2dl/g, the xylene insoluble portion at 20°C is 90% by weight, and the intrinsic viscosity [η]Cxis of the insoluble portion is Propylene of 1.9dl/g, [η]Cxs/[η]Cxis=1.68. Ethylene block copolymer (denoted "BPP-1").

(7) Propylene. Ethylene Block Copolymer-2

The xylene soluble portion at 20°C is 10% by weight, the intrinsic viscosity [η]Cxs of the soluble portion is 3.6dl/g, the xylene insoluble portion at 20°C is 90% by weight, and the intrinsic viscosity [η]Cxis of the insoluble portion is Propylene of 1.82dl/g, [η]Cxs/[η]Cxis=1.98. Ethylene block copolymer (denoted "BPP-2").

(8) Propylene. Ethylene Block Copolymer-3

The xylene soluble part at 20°C is 20% by weight, the intrinsic viscosity [η]Cxs of the soluble part is 2.5dl/g, the xylene insoluble part at 20°C is 80% by weight, and the intrinsic viscosity [η]Cxis of the insoluble part is Propylene of 1.8dl/g, [η]Cxs/[η]Cxis=1.39. Ethylene block copolymer (denoted "BPP-3").

(9) Propylene. Ethylene Block Copolymer-4

The xylene soluble part at 20°C is 20% by weight, the intrinsic viscosity [η]Cxs of the soluble part is 2.6dl/g, the xylene insoluble part at 20°C is 80% by weight, and the intrinsic viscosity [η]Cxis of the insoluble part is Propylene of 1.71dl/g, [η]Cxs/[η]Cxis=1.52. Ethylene block copolymer (denoted "BPP-4").

(10) Low-density polyethylene polymer-1

Linear low-density polyethylene (expressed as "LLDPE") with a density of 0.921 g/cm ³ and an MFR of 2.2 g/10 minutes.

(11) Fatty acid amide lubricants

Fatty acid amide-based lubricants use erucamide.

In Examples 1 to 5 and Comparative Examples 1 to 3, as shown in Table 1, the composition of the layer A was that erucamide was mixed with EPC-1 to EPC-5 of the aforementioned propylene-based random copolymer. The composition of layer B is propylene mixed with [η]Cxs/[η]Cxis ratio [η]Cxs/[η]Cxis of xylene at 20℃ to insoluble part [η]Cxis of 1.68. Ethylene block copolymer (BPP-1), linear low-density polyethylene (LLDPE) which is a low-density polyethylene-based polymer, and erucamide. These are supplied to the respective extruders of the A layer and the B layer, and a two-layer co-extruded non-stretched polypropylene composite film including the A layer/B layer is produced. The thickness of each layer was set at 5 μm/35 μm, 40 μm in total.

In Examples 6 to 9 and Comparative Examples 4 to 10, as shown in Table 1, the composition of layer A and layer C is that erucamide was mixed with EPC-1, a propylene-based random copolymer. The composition of layer B is mixed with propylene. Ethylene block copolymer BPP-1 or BPP-2, LLDPE and propylene random copolymer EPC-1 are mixed with erucamide in the resin composition. These were supplied to the respective extruders of the A layer, the B layer, and the C layer, and a three-layer co-extruded non-stretched polypropylene-based composite film including the A layer/B layer/C layer was produced. The thickness of each layer was set to 5 μm/30 μm/5 μm, 40 μm in total.

In Example 10, the A layer/B layer/C layer had the same raw material composition as in Example 6, and the thickness of each layer was set to 10 μm/60 μm/10 μm, a total of 80 μm.

In Example 11, the composition of layer B used [η] Cxs / [η] Cxis 1.98 of propylene. Ethylene block copolymer (BPP-2), except that according to the same recipe as in Example 6, a three-layer co-extruded non-stretched polypropylene composite film comprising A layer/B layer/C layer was produced.

As shown in Table 1, in Examples 1 to 5, the workability, low-temperature shock resistance, bending whitening resistance, and orange peel resistance are excellent, and the sealing strength at 130°C and 160°C is also sufficient. Below 0.3, the slipperiness is good, and the volume resistivity is also 1×10 ¹¹ ~1×10 ¹⁴ Ω. range of m.

In Examples 6 to 9, although a three-layer co-extruded non-stretched polypropylene-based composite film comprising A layer/B layer/C layer was made, the processability, drawing formability, low temperature shock resistance, Excellent resistance to bending whitening and orange peel, sufficient sealing strength at 130°C and 160°C, static friction coefficient below 0.3, good slipperiness, and volume resistivity of 1×10 ¹¹ ~1×10 ¹⁴ Ω． range of m.

In addition, in Example 10, although the total thickness was set at 80 μm, the workability, drawing formability, low-temperature shock resistance, bending whitening resistance, and orange peel resistance were excellent. The sealing strength is sufficient, the coefficient of static friction is below 0.3, the slipperiness is good, and the volume resistivity is 3.2×10 ¹² Ω. m.

In Example 11, although the composition of the B layer used [η] Cxs / [η] Cxis 1.98 of propylene. Ethylene block copolymer (BPP-2), however, has excellent processability, drawing formability, low temperature impact resistance, bending whitening resistance, orange peel resistance, and sufficient sealing strength at 130°C and 160°C , the coefficient of static friction is below 0.3, the slipperiness is good, and the volume resistivity is 7.0×10 ¹² Ω. m.

In Comparative Example 1, the MFR of layer A exceeds 10 g/10 minutes, and the melting point is less than 130°C. Therefore, the heat seal strength at 160°C is low, the amount of lubricant exuded from the surface layer of layer A is small, and the coefficient of static friction between the surfaces of layers A High, poor slipperiness, poor processability.

In Comparative Example 2, the MFR of the layer A was as low as 1.5 g/10 minutes, so the uniform lamination property of the layer B was poor, the stability of film formation was poor, and the heat seal strength at 130° C. was also low.

In Comparative Example 3, the melting point of layer A is as high as 156°C, so the heat-sealing strength at 130°C and 160°C is low, and the coefficient of static friction between the surfaces of layer A is also high, the slipperiness is poor, and wrinkles are generated during the lamination process. Poor processability.

In Comparative Example 4, the erucamide content in the layer A was as low as 150 ppm, so the amount of lubricant exuded from the surface layer of the layer A was small, the slipperiness was poor, wrinkles were generated during the lamination step, and the workability was poor.

In Comparative Example 5, the erucamide content in the layer A was as high as 2500 ppm, so although the static friction coefficient was 0.3 or less, the lubricant adhered to the processing drum, resulting in poor processability. In addition, since the amount of lubricant in layer A was large, the heat seal strength at 130° C. was also low.

In Comparative Example 6, the blending amount of LLDPE was high, so the low-temperature shock resistance was poor, the amount of lubricant bleed out from the surface layer of the A layer was also small, the slipperiness was poor, and the processability was poor.

In Comparative Example 7, since the blending amount of LLDPE was small, the bending whitening resistance and orange peel resistance were poor, and the heat seal strength was also low.

In Comparative Example 8, the amount of erucamide added to the layer B was as low as 300 ppm, so the amount of lubricant exuded from the surface layer of the layer A was small, and the slipperiness was poor. In addition, the volume resistivity is as high as 2.5×10 ¹⁵ Ω. m, therefore, static electricity is generated, and workability is poor.

In Comparative Example 9, the erucamide content of layer B was as high as 6000 ppm, so the amount of lubricant exuded from the surface layer of layer A became excessive, and the lubricant adhered to the processing roller. In addition, the heat seal strength became low, and the volume resistivity was as low as 3.5×10 ¹⁰ Ω. m, when used as a battery packaging material, the insulation is poor.

In Comparative Example 10, the layer B used propylene with a [η]Cxs/[η]Cxis of 1.39. Ethylene block copolymer (BPP-3) is used as the main component, except that it is the same as Example 6, and a three-layer co-extruded non-stretched polypropylene composite film comprising A layer/B layer/C layer is produced . The thickness of each layer was set to 5 μm/30 μm/5 μm, 40 μm in total. [η]Cxs/[η]Cxis is less than 1.6, so the film is crushed and thinned during heat sealing, and the heat sealing force is reduced. In addition, bleeding of the resin is observed due to the pressure during drawing molding.

In Comparative Example 11, the layer B used propylene with a [η]Cxs/[η]Cxis of 1.52. Ethylene block copolymer (BPP-4) was used as the main component, except that it was the same as in Example 6, and a three-layer co-extruded non-stretched polypropylene composite film comprising A layer/B layer/C layer was produced. . Although [η]Cxs/[η]Cxis was close to 1.6, resin bleeding was observed due to the pressure during drawing molding, and thinning occurred during heat sealing, and the heat seal strength was also low.

In Examples 12 to 21 and Comparative Examples 12 to 15, as shown in Table 1, the composition of layer A is that erucamide is mixed with EPC-1 to EPC-5 of the aforementioned propylene-based random copolymer. The composition of layer B is propylene mixed with [η]Cxs/[η]Cxis ratio [η]Cxs/[η]Cxis of xylene at 20℃ to insoluble part [η]Cxis of 1.68. Ethylene block copolymer (BPP-1), linear low-density polyethylene (LLDPE) as a low-density polyethylene polymer, styrene. Ethylene Butene. Styrene triblock copolymer (SEBS), or polyethylene. Ethylene Butene. Polyethylene triblock copolymer (CEBC), and erucamide. These are supplied to the respective extruders of the A layer and the B layer, and a two-layer co-extruded non-stretched polypropylene composite film including the A layer/B layer is produced. The thickness of each layer was set at 5 μm/35 μm, 40 μm in total.

In Examples 22 to 29 and Comparative Examples 16 to 21, as shown in Table 1, the composition of the A layer and the C layer was mixed with erucamide in EPC-1, a propylene-based random copolymer. B layer composition is in propylene. Ethylene block copolymer BPP-1 or BPP-2, LLDPE, SEBS or CEBC, and propylene-based random copolymer EPC-1 are mixed into a resin composition in which erucamide is mixed. These were supplied to the respective extruders of the A layer, the B layer, and the C layer, and a three-layer co-extruded non-stretched polypropylene-based composite film including the A layer/B layer/C layer was produced. The thickness of each layer was set to 5 μm/30 μm/5 μm, 40 μm in total.

In Example 30, the A layer/B layer/C layer had the same raw material composition as in Example 22, and the thickness of each layer was 10 μm/60 μm/10 μm, totaling 80 μm.

As shown in Table 1, in Examples 12 to 21, the workability, low-temperature shock resistance, and bending whitening resistance are more excellent, the sealing strength at 130°C and 160°C is also sufficient, and the coefficient of static friction is 0.3 or less. Good slipperiness, volume resistivity is also 1×10 ¹¹ ~1×10 ¹⁴ Ω. range of m.

In Examples 22 to 29, although a three-layer co-extruded non-stretched polypropylene-based composite film comprising A layer/B layer/C layer was produced, the processability, drawing formability, and low-temperature impact resistance , Excellent bending and whitening resistance, sufficient sealing strength at 130°C and 160°C, static friction coefficient below 0.3, good slipperiness, volume resistivity also 1×10 ¹¹ ~1×10 ¹⁴ Ω. range of m.

In addition, in Example 30, although the total thickness was set at 80 μm, the workability, drawing formability, low-temperature shock resistance, and bending whitening resistance were excellent, and the sealing strength at 130°C and 160°C was also sufficient. , the coefficient of static friction is below 0.3, and the slipperiness is good, and the volume resistivity is 3.2×10 ¹² Ω. m.

In Comparative Examples 12 and 13, the MFR of the A layer exceeds 10 g/10 minutes, and the melting point is less than 130°C. Therefore, the heat-sealing strength at 160°C is low, and the amount of lubricant exuded from the surface layer of the A layer is small. High coefficient of static friction, poor slipperiness, poor processability.

In Comparative Example 14, the MFR of the layer A was as low as 1.5 g/10 minutes, so the uniform lamination property of the layer B was poor, the stability of film formation was poor, and the heat seal strength at 130° C. was also low.

In Comparative Example 15, the melting point of layer A is as high as 156°C, so the heat-sealing strength at 130°C and 160°C is low, the static friction coefficient between the surfaces of layer A is also high, the slipperiness is poor, and wrinkles are generated in the lamination process. Poor processability.

In Comparative Example 16, the erucamide content in the layer A was as low as 150 ppm, so the amount of lubricant exuded from the surface layer of the layer A was small, the slipperiness was poor, wrinkles were generated during the lamination step, and the workability was poor.

In Comparative Example 17, the erucamide content in the A layer was as high as 2500 ppm, so although the static friction coefficient was 0.3 or less, the lubricant adhered to the processing drum, resulting in poor processability. In addition, since the amount of lubricant in layer A was large, the heat seal strength at 130° C. was also low.

In Comparative Example 18, the LDPE blending amount of the B layer was high, so the low-temperature shock resistance was poor, and the amount of lubricant oozing out of the surface layer of the A layer was also small, and the slipperiness was poor, and the workability was poor.

In Comparative Example 19, since the amount of LLDPE blended in the B layer was small, the bending whitening resistance was poor, and the heat seal strength was also low.

In Comparative Example 20, the addition amount of erucamide in the B layer was as low as 300 ppm, so the amount of lubricant exuded from the surface layer of the A layer was small, and the slipperiness was poor. In addition, the volume resistivity is as high as 2.5×10 ¹⁵ Ω. m, therefore, static electricity is generated and workability is poor.

In Comparative Example 21, the erucamide content of layer B was as high as 6,000 ppm, so the amount of lubricant exuded from the surface layer of layer A became excessive, and the lubricant adhered to the processing drum. In addition, the heat seal strength became low, and the volume resistivity was as low as 3.5×10 ¹⁰ Ω. m, when used as a battery packaging material, the insulation is poor.

[Possibility of industrial use]

The polypropylene-based composite film of the present invention and the packaging material using it have high heat-sealing force and excellent slipperiness, and are suitable for use as exterior packaging of batteries. In addition, the polypropylene-based composite film of the present invention and the packaging material using the same have excellent slipperiness, low-temperature shock resistance, and orange peel resistance, and are suitable for use as retort food packaging materials that require heat-sealing strength at low temperatures.

Claims (14)

A polypropylene-based composite film is characterized in that: it contains at least two layers of A layer/B layer, and the A layer is a propylene-based random film with a melt flow rate of 230°C of 2-10g/10 minutes and a melting point of 130-150°C. The copolymer is the main component, and the B layer is based on the ratio of the limiting viscosity [η]Cxs of the soluble part to the limiting viscosity [η]Cxis of the insoluble part relative to xylene at 20 °C ([η]Cxs/[η]Cxis) Propylene above 1.6. 100 parts by weight of ethylene block copolymer (a), blended with a resin composition of 10 to 90 parts by weight of low-density polyethylene polymer (b) as the main component, layer A contains 200 to 2000 ppm of fatty acid amide lubricant, B layer contains fatty acid amide lubricant 500~5000ppm; where B layer is relative to the aforementioned propylene. 100 parts by weight of an ethylene block copolymer (a), further blended with 10 to 50 parts by weight of a propylene-based random copolymer (d) with a melt flow rate of 2 to 10 g/10 minutes at 230°C and a melting point of 130 to 150°C . Such as the polypropylene composite film of claim 1, wherein the B layer is relative to the aforementioned propylene. Ethylene block copolymer (a) 100 parts by weight, polymer (c) 5 to 20 parts by weight further blended with a block copolymer having a styrenic block or a block copolymer having a crystalline olefin block . Such as the polypropylene composite film of claim 2, wherein the polymer (c) of the aforementioned layer B is styrene. Ethylene Butene. Styrene triblock copolymer. Such as the polypropylene composite film of claim 2, wherein the polymer (c) of the aforementioned layer B is polyethylene. Ethylene Butene. Polyethylene triblock copolymer things. Such as the polypropylene-based composite film of claim 1, which contains a propylene-based random copolymer with a melt flow rate of 230°C of 2-10g/10 minutes and a melting point of 130-150°C as the main component, and contains fatty acid acyl Three-layer laminate of layer A/layer B/layer C with amine lubricant 200~2000ppm. For example, the polypropylene-based composite film of claim 5, wherein the thickness of the C layer is more than 1 μm, and the total thickness is in the range of 20-200 μm. For example, the polypropylene-based composite film of claim 1, wherein the thickness of layer A is more than 1 μm, and the total thickness is in the range of 20 to 200 μm. The polypropylene-based composite film according to claim 1, wherein the coefficient of static friction between the surfaces of the layers A is 0.3 or less after aging at 23°C for 3 days. The polypropylene-based composite film according to claim 1, wherein after aging at 60° C. for 3 days, the coefficient of static friction between the surfaces of the layers A is 0.3 or less. The polypropylene-based composite film according to any one of claims 1 to 9, wherein the volume resistivity is 1×10 ¹¹ ~1×10 ¹⁴ Ω. range of m. A kind of laminated body, it is in the polypropylene composite film as any one in claim 1 to 10 is not a layer on the side of A layer, is selected from biaxially stretched polyethylene terephthalate film, biaxially stretched polyethylene terephthalate film, biaxially stretched polyethylene terephthalate film, At least one selected from the group consisting of acrylic film, biaxially stretched nylon film and aluminum foil. The laminated body of claim 11, wherein after the aforementioned lamination, the surfaces of layer A of the polypropylene-based composite film are heated to each other at 130°C. The sealing strength is above 30N/15mm, and the heat sealing strength above 160°C is above 55N/15mm. A packaging material for batteries, which uses the laminate according to claim 11 or 12. A packaging material for cooking, which uses the laminate as claimed in claim 11 or 12.