JP2021113266A - Readily-tearable low gloss film, and packaging bag and sheet comprising the same - Google Patents

Abstract

To provide a readily-tearable low gloss film that is excellent in low glossiness as well as in ease of tear and impact strength and a packaging bag and a sheet comprising the same.SOLUTION: A readily-tearable low gloss film consists of a single layer or multiple layers, the readily-tearable low gloss film containing at least a copolymer (a) containing ethylene and a functional group-containing monomer and a cyclic olefinic resin (b) in any layer.SELECTED DRAWING: None

Description

The present invention relates to an easily tearable film, a film having low gloss and excellent impact strength, and a packaging bag and a sheet using the same.

In recent years, against the background of declining birthrate and aging population, declining working population, reduction of long working hours, etc., there is an increasing demand for user-friendly plastic film and sheet products such as easy opening. In addition, due to growing awareness of environmental issues around the world, efforts will be made not only for convenience and usability, but also for reducing the volume and thickness of plastic film and sheet products with the aim of reducing the environmental burden. Is becoming.
Examples of applications that require easy opening and tearing include the food packaging field. The performance required for packaging films and sheets in the food packaging field includes strength, heat sealability, designability, etc., in addition to the above-mentioned easy-opening property and easy-tearing property. In particular, with regard to design, in general, it is required that the contents are transparent and glossy and the contents are highly visible, while a low gloss and matte appearance is required because a high-class feeling can be produced. There are many cases.

As a method for imparting low gloss as described above, for example, Patent Document 1 describes an ethylene / α-olefin copolymer component obtained by polymerizing ethylene and an α-olefin having 3 to 12 carbon atoms and oxygen content. A low-gloss polyethylene film composed of an ethylene-based copolymer component is described. Further, Patent Document 2 describes a low-reflection sheet having a low-reflection resin layer having a large number of protrusions on at least one surface side of the colored base material.

JP-A-2002-105252 Japanese Unexamined Patent Publication No. 2016-29456

Although the means for imparting low gloss to the packaging film or sheet has been studied as described above, it cannot be said that the film described in Patent Document 1 has sufficient low gloss, and the tear strength is high, so that it can be used as a packaging bag. Inferior in easy opening when used. In the sheet described in Patent Document 2, transfer formation using a soft mold is required to form the protrusions, which poses a problem in terms of cost.
An object of the present invention is to provide an easily tearable low gloss film which is excellent not only in low gloss property but also in easy tearability and impact strength, and a packaging bag and a sheet using the same.

As a result of diligent studies by the present inventor in order to solve the above-mentioned problems, it has been found that a film and a sheet capable of solving the above-mentioned problems can be obtained by a specific raw material composition, and the present invention has been reached.
That is, according to the first invention, the copolymer (a) and the cyclic olefin resin (b), which are single-layer or multi-layer easily tearable low-gloss films and contain at least ethylene and a functional group-containing monomer, are used. An easily tearable low-gloss film characterized by being contained in any layer is provided.
According to the second invention, the functional group-containing monomer is at least one selected from the group consisting of vinyl acetate, acrylic acid, acrylic acid ester, and maleic anhydride. The easily tearable low-gloss film described in the above is provided.
According to the third invention, at least a resin layer (A) containing the copolymer (a) as a main component, a cyclic olefin resin (b), and a resin layer (B) containing a polyolefin resin (c). The easily tearable low-gloss film according to the first or second invention, wherein a plurality of resin layers including two layers are laminated and the resin layer (A) is arranged on the outermost layer. Will be done.
According to the fourth invention, the concentration of the cyclic olefin resin (b) in the resin layer (b) is 10 to 80% by weight, and the concentration of the polyolefin resin (c) is 20 to 90% by weight. The easily tearable low-gloss film according to the third invention is provided.
According to a fifth invention, there is provided an easily tearable low-gloss film according to any one of the third to fourth inventions, wherein the polyolefin-based resin (c) is a polyethylene-based resin. ..
According to the sixth invention, the easily tearable low gloss according to any one of the first to fifth inventions, wherein the cyclic olefin resin (b) is an ethylene / cyclic olefin copolymer. Film is provided.
According to the seventh invention, there is provided the easily tearable low-gloss film according to the sixth invention, wherein the ethylene / cyclic olefin copolymer has a glass transition point of 60 ° C. or higher.
According to an eighth invention, there is provided an easily tearable low gloss film according to any one of the first to seventh inventions, which further comprises a branched polyolefin in at least one of the layers.
According to a ninth invention, there is provided an easily tearable low-gloss film according to any one of the third to seventh inventions, wherein the resin layer (A) further contains a branched polyolefin. ..
According to the tenth invention, any one of the first to ninth inventions characterized in that the tear strength of MD and TD measured by the Ermendorf tear strength based on JIS K7128-2 is 20 N / mm or less. The easily tearable low-strength film described is provided.
According to the eleventh invention, in the glossiness measurement at an incident angle and a light receiving angle of 20 ° based on JIS Z8741, the glossiness of at least one outermost layer surface of the film is 10% or less. The easily tearable low-gloss film according to any tenth is provided.
According to the twelfth invention, in the dirt drop impact measurement based on JIS K7124, the low tearability according to any one of the first to eleventh inventions, characterized in that the impact strength at 70 μm is 300 g or more. A glossy film is provided.
According to the thirteenth invention, the easily tearable low-gloss film according to the first to twelfth inventions, wherein the copolymer (a) is a copolymer composed of ethylene and methyl acrylate. Provided.
According to the fourteenth invention, a packaging bag using the easily tearable low-gloss film according to any one of the first to thirteenth inventions is provided.
According to the fifteenth invention, a sheet using the easily tearable low-gloss film according to any one of the first to thirteenth inventions is provided.

As described above, according to the first invention, by containing the copolymer (a) containing at least ethylene and a functional group-containing monomer and the cyclic olefin resin (b), the film is easily torn, has low gloss, and has an impact. Excellent in strength.
Further, according to the second invention, the functional group-containing monomer is at least one selected from the group consisting of vinyl acetate, acrylic acid, acrylic acid ester, and maleic anhydride, so that the film has low gloss and impact strength. Excellent for.
Further, according to the third invention, at least two of the resin layer (A) containing the copolymer (a) as a main component, the cyclic olefin resin (b), and the resin layer (B) containing the polyolefin resin (c). By laminating a plurality of resin layers including a layer and arranging the resin layer (A) on the outermost layer, the film is more excellent in tearability and low gloss.
Further, according to the fourth invention, the concentration of the cyclic olefin resin (b) in the resin layer (b) is 10 to 80% by weight, and the concentration of the polyolefin resin (c) is 20 to 90% by weight. , The film is superior in tearability.
Further, according to the fifth invention, since the polyolefin-based resin (c) is a polyethylene-based resin, the film is superior in impact strength.
Further, according to the sixth invention, since the olefin resin (b) is an ethylene / cyclic olefin copolymer, the film is more excellent in tearability.
Further, according to the seventh invention, when the glass transition point of the ethylene / cyclic olefin copolymer is 60 ° C. or higher, the film is more excellent in tearability.
Further, according to the eighth invention, the low glossiness of the film is further improved by further including the branched polyolefin in at least one of the layers.
Further, according to the ninth invention, the low glossiness of the film is further improved by further containing the branched polyolefin in the resin layer (A).
Further, according to the tenth invention, the film is further excellent in tearability because the tear strength of MD and TD measured by the Elmendorf tear strength based on JIS K7128-2 is 20 N / mm or less.
Further, according to the eleventh invention, in the glossiness measurement at the incident angle and the light receiving angle of 20 ° based on JIS Z8741, the glossiness of at least one outermost layer surface of the film is 10% or less, so that the film is further lowered. Excellent gloss.
Further, according to the twelfth invention, in the dirt drop impact measurement based on JIS K7124, the impact strength at 70 μm is 300 g or more, so that the film is further excellent in impact strength.
Further, according to the thirteenth invention, since the copolymer (a) is a copolymer composed of ethylene and methyl acrylate, the film is excellent in low glossiness and impact strength.
Further, according to the fourteenth invention, a packaging bag having low gloss, easy tearability, and excellent impact strength is provided.
Further, according to the fifteenth invention, a sheet having low gloss, easy tearability, and excellent impact strength is provided.

Hereinafter, the easily tearable low-gloss film of the present invention will be described in detail for each item. In the present invention, "having a certain component as a main component" means that the component is a main component in the composition or the resin component constituting the layer, and specifically, the resin component constituting the layer. It means that the content is 50% by weight or more, preferably 70% by weight or more, more preferably 90% by weight or more, still more preferably 100% by weight.

1. 1. Ingredients constituting an easily tearable low-gloss film 1-1. Copolymer (a)
The copolymer (a) of the present invention is a copolymer containing at least ethylene and a functional group-containing monomer. By using the copolymer (a) particularly for the outermost layer of the film, the glossiness of the outer surface of the film can be lowered and the impact strength can be increased. The copolymer may be a block copolymer or a random copolymer. The ethylene unit contained in the copolymer (a) may be low-density polyethylene (LDPE) having a large number of branched branches or linear low-density polyethylene (LLDPE). As the ethylene, ethylene derived from a non-petroleum raw material such as a plant raw material can be used as well as ethylene derived from a petroleum raw material.

The functional group-containing monomer means a monomer having at least one functional group other than the group involved in copolymerization with ethylene. Examples of the functional group contained in the functional group-containing monomer include an ether group, a hydroxyl group, an ester group, a carbonyl group, an amino group, and an amide group. From the viewpoint of improving low gloss and impact strength, it is preferable to use a functional group-containing monomer having an ester group.

Non-limiting examples of the functional group-containing monomer include vinyl acetate, acrylic acid, acrylic acid esters such as methyl acrylate and ethyl acrylate, methacrylic acid esters such as methyl methacrylate and ethyl methacrylate, and maleic anhydride. Be done. It is preferable to use methyl acrylate from the viewpoint of improving low gloss and impact strength. As the functional group-containing monomer, only one type may be used in the copolymer (a), or two or more types of monomers may be used in combination.
When two or more kinds of functional group-containing monomers are used in combination, the amount ratio of each can be determined in an arbitrary range according to the desired film characteristics, and is not particularly limited.

The copolymer (a) may be a copolymer further containing ethylene and a monomer other than the functional group-containing monomer. Non-limiting examples of such monomers include α-olefins having 3 to 20 carbon atoms represented by the _{structural formula: CH 2} = CHR ^{18 (where R 18} has 1 to 18 carbon atoms). It is a hydrocarbon group of the above, and may have a linear structure or a branch). The number of carbon atoms of the α-olefin is more preferably 3 to 12. More specifically, propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 3-methyl-1-butene, 4-methyl-1-pentene and the like can be mentioned. When a monomer other than ethylene and a functional group-containing monomer is further contained, the content of such a monomer is preferably in the range of 1% by weight to 30% by weight with respect to the entire copolymer (a), and is preferably 3% by weight. More preferably, it is in the range of% to 25% by weight. Within this range, it is possible to introduce the physical characteristics of the added monomer while maintaining favorable low glossiness and impact strength.

The copolymer (a) includes, for example, a copolymer of ethylene polymerized by a metal catalyst such as a metallocene catalyst and a polar group-containing monomer, or both ethylene and vinyl acetate polymerized using an organic peroxide as a reaction initiator. Polymer (EVA), ethylene / methyl acrylate copolymer (EMA), ethylene / ethyl acrylate copolymer (EEA), ethylene / methyl methacrylate copolymer (EMMA), ethylene / acrylate copolymer (EMA) EAA), ethylene / acrylic acid / maleic anhydride three-component copolymer and the like can be mentioned.

In the present invention, from the viewpoint of low gloss and impact strength, the copolymer (a) is an ethylene / methyl acrylate copolymer (EMA), an ethylene / ethyl acrylate copolymer (EEA), or an ethylene / methyl methacrylate copolymer. A copolymer (EMMA) is preferable, and a methyl ethylene / methyl acrylate copolymer (EMA) is more preferable.

Regarding the amount relationship between ethylene and the functional group-containing monomer in the copolymer (a), the content of the functional group-containing monomer is preferably in the range of 10% by weight to 30% by weight with respect to the entire copolymer (a). More preferably, it is in the range of 12.5% by weight to 27.5% by weight. If the content of the functional group-containing monomer is less than 10% by weight, low glossiness and impact strength may be deteriorated, which is not preferable. The content of the functional group-containing monomer can be controlled by adjusting the blending ratio of each monomer in the step of preparing the copolymer (a).

The melt flow rate (MFR) of the copolymer (a) of the present invention under a load of 190 ° C. and 2.16 kg is preferably 0.1 to 20 g / 10 min, more preferably 1 to 10 g / 10 min. If the MFR is less than 0.1 g / 10 min, the extrusion characteristics are deteriorated, which is not preferable. On the other hand, if the MFR is more than 20 g / 10 min, the film forming stability is deteriorated, which is not preferable. The melt flow rate (MFR) is measured by a method according to JIS K7210: 1999.

As the copolymer (a), a commercially available product can be used, but it can also be produced by using the above-mentioned monomers. Copolymerization methods using a metal catalyst such as a metallocene catalyst and copolymerization using an organic peroxide as a reaction initiator are known to those skilled in the art.

As a commercially available product that can be used as the copolymer (a), as the ethylene / methyl acrylate copolymer (EMA), for example, "REXPERL EMA" manufactured by Nippon Polyethylene Co., Ltd., etc. Examples of the ethylene / ethyl acrylate copolymer (EEA) include "REXPERL EEA" manufactured by Nippon Polyethylene Co., Ltd., and an ethylene / methyl methacrylate copolymer (EEA). Examples of EMMA) include "Acryft (registered trademark)" manufactured by Sumitomo Chemical Corporation.

1-2. Cyclic olefin resin (b)
The cyclic olefin resin (b) of the present invention may be a polymer using at least one type of monomer of cyclic olefin, and may be a copolymer. For example, a norbornene-based polymer, a vinyl alicyclic hydrocarbon polymer, a cyclic conjugated diene polymer and the like can be mentioned. Among these, norbornene-based polymers are preferable.

［一般式（１）中、Ｒ^１〜Ｒ^１２は、それぞれ同一でも異なっていてもよく、水素原子、ハロゲン原子、及び、炭素数１〜２０の炭化水素基からなる群より選ばれるものであり、Ｒ^９及びＲ^１０、並びに、Ｒ^１１及びＲ^１２は、各々一体化して２価の有機基を形成してもよく、Ｒ^９又はＲ^１０と、Ｒ^１１又はＲ^１２とは、互いに環を形成していてもよい。
また、ｎは、０又は正の整数を示し、ｎが２以上の場合には、Ｒ^５〜Ｒ^８は、それぞれの繰り返し単位の中で、それぞれ同一でも異なっていてもよい。］ Examples of the cyclic olefin used in the cyclic olefin co-resin (b) include compounds having the following structures.

[In the general formula (1), R ^{1 to} R ¹² may be the same or different, and are selected from the group consisting of a hydrogen atom, a halogen atom, and a hydrocarbon group having 1 to 20 carbon atoms. , R ⁹ and R ¹⁰ , and R ¹¹ and R ¹² may be integrated to form a divalent organic group, respectively, and R ⁹ or R ¹⁰ and R ¹¹ or R ¹² may ring each other. It may be formed.
Further, n indicates 0 or a positive integer, and when n is 2 or more, R ^{5 to} R ⁸ may be the same or different in each repeating unit. ]

Examples of the cyclic monomer include norbornene-based olefins, such as norbornene, vinylnorbornene, etilidennorbornene, norbornadiene, tetracyclododecene, tricyclo [4.3.0.1 ^2,5 ], and tricyclo [4.3.0. 1 ^{2, 5} ] Compounds having a cyclic olefin skeleton such as deca-3-ene are mentioned, and 2-norbornene (NB) and tetracyclo [6.2.1.1 ^3,6 . 0 ^2,7 ] Dodeca-4-en or the like may be used.

Examples of the norbornene-based polymer include a ring-opened polymer of a norbornene-based monomer (hereinafter, also referred to as “COP”), and a norbornene-based copolymer obtained by copolymerizing a norbornene-based monomer and an α-olefin such as ethylene (hereinafter, also referred to as “COP”). Hereinafter, it is also referred to as “COC”) and the like. Also, hydrogenated COP and COC can be used.

The COC includes linear monomers such as α-olefins such as ethylene, propylene, butene-1, penten-1, hexene-1, heptene-1, and octene-1, and cyclic monomers such as tetracyclododecene and norbornene. Examples thereof include a cyclic olefin copolymer obtained from. More specifically, the linear monomer and monocycloalkene and bicyclo [2.2.1] -2-heptene (norbornen) having 3 to 20 carbon atoms and their derivatives, tricyclo [4.3.0.12] , 5] -3-decene and its derivatives, tetracyclo [4.4.0.1.2.2.5.17,10] -3-dodecene and its derivatives, pentacyclo [6.5.1.13,6.02] , 7.09,13] -4-pentadecene and its derivatives, pentacyclo [7.4.0.12,5.19,12.08,13] -3-pentadecene and its derivatives, pentacyclo [8.4.0] .12, 5.19, 12.08, 13] -3-hexadecene and its derivatives, pentacyclo [6.6.1.13, 6.02, 7.09,14] -4-hexadecenes and their derivatives, hexacyclo [6.6.1.13, 6.110, 13.02, 7.09, 14] -4-heptadecene and its derivatives, heptacyclo [8.7.0.12, 9.14, 7.111, 17] .03, 8.012, 16] -5-eikosen and its derivatives, heptacyclo [8.7.0.13, 6.110, 17.112, 15.02, 7.011, 16] -4-eikosen And its derivative, heptacyclo [8.8.0.12, 9.14, 7.111, 18.03, 8.012, 17] -5-heneikosen and its derivative, octacyclo [8.8.0.12]. 9.14, 7.111, 18.113, 16.03, 8.012, 17] -5-docosen and its derivatives, nonacyclo [10.9.1.14, 7.113, 20.115, 18. 02, 10.03, 8.012, 21.014, 19] -Cyclic olefin copolymer composed of a copolymer with a cyclic olefin such as pentacocene and a derivative thereof can be mentioned. The linear monomer and the cyclic monomer can be used alone or in combination of two or more. Moreover, such a cyclic olefin copolymer can be used alone or in combination. Further, the COP and COC can be used in combination with the cyclic olefin resin (b). In that case, different performances of COP and COC can be imparted.

In the present invention, the cyclic olefin resin (b) is preferably COC because of its dispersibility in polyethylene. The COC is preferably an ethylene / cyclic olefin copolymer in which the linear monomer is ethylene. Furthermore, the cyclic monomer is preferably norbornene or the like.

Further, in the present invention, when the ethylene / cyclic olefin copolymer is used as the cyclic olefin resin (b), the content ratio of ethylene / cyclic olefin is 15 to 40/85 to 60 by weight. Is preferable. More preferably, it is 30 to 40/70 to 60. If ethylene is less than 15% by weight, the rigidity becomes too high, which may deteriorate inflation moldability and bag making suitability, which is not preferable. On the other hand, when ethylene is 40% by weight or more, sufficient tearability and rigidity may not be obtained, which is not preferable. When the content ratio is in this range, the rigidity, tearability, processing stability, and impact strength of the film are improved, which is preferable.

Furthermore, the ethylene / cyclic olefin copolymer preferably has a glass transition point of 60 ° C. or higher. More preferably, it is 70 ° C. or higher. When the content of the cyclic olefin is less than the above range, the glass transition point becomes less than the above range, for example, the barrier property of the aromatic component is lowered, sufficient rigidity cannot be obtained, and the suitability for high-speed packaging machines is not obtained. There is a risk of being inferior to. On the other hand, if the content of the cyclic olefin exceeds the above range, the glass transition point becomes too high, and the melt moldability of the copolymer and the adhesiveness with the olefin resin may decrease, which is not preferable.

As described above, the cyclic olefin resin (b) may contain a monomer having a chain structure such as ethylene as a comonomer. Not only ethylene but also α-olefins having 3 to 20 carbon atoms can be used as the comonomer of the cyclic olefin resin (b). When such a comonomer is used instead of ethylene, the content ratio can be in the range according to the description for ethylene. Further, such a comonomer can be used in addition to the ethylene / cyclic olefin copolymer.

The weight average molecular weight of the cyclic olefin resin (b) is preferably 5,000 to 500,000, more preferably 7,000 to 300,000.

As a commercially available product that can be used as the cyclic olefin resin (b), examples of the ring-opening polymer (COP) of the norbornene-based monomer include "ZEONOR" manufactured by Nippon Zeon Co., Ltd., and the norbornene-based polymer is used. Examples of the copolymer (COC) include "Apel" manufactured by Mitsui Kagaku Co., Ltd. and "TOPAS" manufactured by Polyplastics Co., Ltd. In the present invention, TOPAS grade 8007 is preferable because the content ratio of the norbornene-based monomer is in the above range, processability, and the like.

1-3. Polyolefin resin (c)
In the film of the present invention, it is preferable that the layer containing the cyclic olefin resin (b) contains the polyolefin resin (c). The polyolefin-based resin may be either a polyethylene-based resin or a polypropylene-based resin, but it is more preferable to use a polyethylene-based resin.
When the polyolefin-based resin is a polyethylene-based resin, it is polymerized using a homopolyethylene or an ethylene / α-olefin copolymer polymerized by a metallocene catalyst, a Ziegler catalyst, a Phillips catalyst, or the like, or an organic peroxide as a reaction initiator. High-pressure method low-density polyethylene and the like can be mentioned, but an ethylene / α-olefin copolymer (linear low-density polyethylene) having a linear molecular structure is preferable from the viewpoint of interfacial strength with the cyclic olefin resin. The density of the polyethylene-based resin is not particularly limited as long as it ^{is 0.800 g / cm 3 to} 0.970 g / cm ^{3, which is a general density range of polyethylene.} Examples of the type of α-olefin copolymerized with ethylene include α-olefins having 3 to 8 carbon atoms, specifically propylene, butene-1, pentene-1, hexene-1, heptene-1, and octene-. Examples thereof include 1,4-methylpentene-1 and the like. In the present invention, the density is a value measured based on JIS K6922-2.

The melt flow rate (MFR) of the polyethylene resin at 190 ° C. is preferably 20 g / 10 min or less from the viewpoint of film formation stability. If the MFR exceeds 20 g / 10 min, the film-forming stability may deteriorate due to a decrease in the melt tension.

When the polyolefin-based resin is a polypropylene-based resin, examples thereof include a propylene homopolymer, a random copolymer of propylene and other α-olefins such as ethylene and butene-1, and a block copolymer. Can also be used. It may be one kind or a blend of two or more kinds of the above-mentioned polymers, but from the viewpoint of the interfacial strength with the cyclic olefin resin, the linear ethylene / propylene / random block copolymer obtained from the metallocene catalyst is used. It is preferable to use coalescence as the main component, and examples thereof include the Wintec (registered trademark) series manufactured by Nippon Polypro Co., Ltd.

The melt flow rate (MFR) of the polypropylene resin at 230 ° C. is preferably 15 g / 10 min or less from the viewpoint of film formation stability under high temperature molding. If the MFR exceeds 15 g / 10 min, the film-forming stability may deteriorate due to a decrease in melt tension.

2. Easy-to-tear low-gloss film The easy-to-tear low-gloss film of the present invention comprises, as described above, any layer of a copolymer (a) containing at least ethylene and a functional group-containing monomer and a cyclic olefin resin (b). The film is characterized by being contained in, and may have either a single-layer structure or a multi-layer structure. For example, in the case of a single layer structure, a single layer film composed of the copolymer (a) and the cyclic olefin resin (b), or a copolymer (a), the cyclic olefin resin (b) and the polyolefin resin (b). Examples thereof include a single-layer film made of c). Further, in the case of a multilayer structure, for example, from the resin layer (A) containing the copolymer (a) as a main component, the resin layer (B) containing the cyclic olefin resin (b) and the polyolefin resin (c). A three-layer film that is composed of at least and is laminated in the order of resin layer (A) / resin layer (B) / resin layer (A) from the outermost layer side, and similarly, a polyolefin resin (c) is used as a main component. Five layers including the resin layer (C) to be laminated, and the resin layer (A) / resin layer (C) / resin layer (B) / resin layer (C) / resin layer (A) are laminated in this order from the outermost layer side. Examples include film. In the case of a multi-layer structure, it is preferable that the resin layer (A) exhibiting low gloss is arranged on one of the outermost layers. That is, it is preferable that at least one of the layers on the surface of the film contains the copolymer (a). There is no particular limit to the number of layers that can be stacked.

When the easily tearable low-gloss film has a single-layer structure, the film contains a copolymer (a) and a cyclic olefin resin (b), and optionally a polyolefin resin (c). The blending amount of the copolymer (a) is preferably 10% by weight to 99% by weight, more preferably 15% by weight to 80% by weight, based on the entire film. The blending amount of the cyclic olefin resin (b) is preferably 1 to 90% by weight, more preferably 20% by weight to 85% by weight, based on the entire film. The blending amount of the polyolefin resin (c) can be arbitrarily designed according to the total amount of the copolymer (a) and the cyclic olefin resin (b), but the cyclic olefin resin (b) is 100% by weight. It is more preferable that the portion is in the range of 40 parts by weight to 160 parts by weight.

When the easily tearable low-gloss film has a multi-layer structure, the resin layer (A) contains the above-mentioned copolymer (a) as a main component. Therefore, the resin layer (A) contains the copolymer (a) in an amount of 50% by weight or more, preferably 70% by weight or more, and more preferably 90% by weight or more. The resin layer (A) may be a layer composed of only the copolymer (a). When the resin layer (A) contains a component other than the copolymer (a), the other components constituting the resin layer (A) include the cyclic olefin resin (b) and the polyolefin resin (c). Can be mentioned. In particular, when the polyolefin-based resin (c) is contained, a polyethylene-based resin is preferable from the viewpoint of compatibility with the copolymer (a), and it is preferable to add a branched polyolefin. Examples of the branched polyethylene include high-pressure low-density polyethylene polymerized using an organic peroxide as a reaction initiator, and linear low-density polyethylene obtained by a specific catalytic polymerization and introduced with long-chain branching. However, more preferably, the high pressure method low density polyethylene is used. The addition of these branched polyolefins, particularly preferably branched polyethylene, further improves low gloss. When a branched polyolefin is used, it is preferably blended in the resin layer (A), but it may be blended in another resin layer as described later, and it is low by containing the branched polyolefin in at least one of the layers. The glossiness can be further improved. The MFR of the branched polyolefin, particularly the branched low-density polyethylene at 190 ° C. and a load of 2.16 kg, is 0.05 to 10 g / 10 min, preferably 0.1 to 5.0 g / 10 min, and more preferably 0. .1 to 2.0 g / 10 min. If the MFR is less than 0.05 g / 10 min, the extrusion processability may be deteriorated, which is not preferable, and if the MFR is more than 10 g / 10 min, the low glossiness may be deteriorated, which is not preferable. The density may range from ^{0.9000 to 0.935 g / cm 3} , preferably 0.919 to 0.927 g / cm ^3. The amount of these branched polyolefins added is 2 to 50% by weight, preferably 3 to 35% by weight, and more preferably 5 to 30% by weight, based on the entire resin composition constituting the resin layer (A). ..

When the easily tearable low-gloss film has a multilayer structure, the resin layer (B) contains a cyclic olefin resin (b) and a polyolefin resin (c). The concentration of the cyclic olefin resin (b) in the resin layer (B) is preferably 10 to 80% by weight, more preferably 20 to 60% by weight. If the concentration of the cyclic olefin resin is less than 10% by weight, the tearability may be deteriorated, which is not preferable, and if it exceeds 80% by weight, the film forming stability may be deteriorated, which is not preferable. The concentration of the polyolefin resin (c) in the resin layer (B) is preferably 20 to 90% by weight, more preferably 40 to 80% by weight.

The resin layer (B) may contain a resin other than the cyclic olefin resin (b) and the polyolefin resin (c). As an example of such a resin, the copolymer (a) or the branched polyolefin can be blended. Specific examples of the copolymer (a) or the branched polyolefin are as described above. The blending amount of such a resin is not particularly limited as long as the total of the cyclic olefin resin (b) and the polyolefin resin (c) is 30% by weight or more with respect to the entire resin layer.

The easily tearable low-gloss film of the present invention may contain a resin layer other than the resin layers (A) and (B). As such a resin layer, a resin layer (C) such as a layer made of only the cyclic olefin resin (b), a layer made of only the polyolefin resin (c), or a layer made of branched polyolefin can be used. can. Further, other layers known to those skilled in the art, such as an adhesive layer between layers, may be provided as long as the object of the present invention is not impaired.

In the present invention, each resin layer constituting the film has an antifogging agent, an antistatic agent, a heat stabilizer, a nucleating agent, an antioxidant, a lubricant, an antiblocking agent, a mold release agent, an ultraviolet absorber, and the like. Ingredients such as colorants and foaming agents can be added within a range that does not impair the object of the present invention. In particular, it is preferable to appropriately add a lubricant or an anti-blocking agent in order to impart processing suitability at the time of film molding and packaging suitability of the filling machine.

The thickness of the easily tearable low-gloss film is preferably 20 to 200 μm, more preferably 30 μm to 200 μm. When the thickness of the multilayer film is in the range of 30 to 200 μm, it can be used as a packaging material by heat-sealing the layers exposed on the outermost surface. Further, when the thickness of the multilayer film is 50 μm or more, excellent secondary moldability can be obtained. When the film has a multilayer structure, the thickness of the resin layer (B) is preferably 20 to 70% with respect to the entire film. More preferably, it is 20 to 50%. For example, in the case of adopting a three-layer structure of a resin layer (A) / a resin layer (B) / a resin layer (A), the thickness of each is about 1: 0.5: 1 to about 1: 4: 1. Can be taken. If the thickness of the resin layer (B) is thinner than 20% of the whole, sufficient tearability may not be obtained, which is not preferable. On the other hand, if it is thicker than 70%, the rigidity becomes too high, which may deteriorate inflation moldability and bag making suitability, which is not preferable. When the thickness of the resin layer (B) is in this range, it is preferable because it is excellent in tearability and is advantageous in terms of cost.

The easily tearable low-reflection film of the present invention is produced by molding into a film or a sheet by air-cooled inflation, water-cooled inflation, a T-die chill roll method, or the like. For example, in the case of a single-layer structure, at least the copolymer (a) and the cyclic olefin resin (b) may be heated and melted in the same extruder to be produced by the above processing method. Further, in the case of a multi-layer structure, for example, the resin layer (A) and the resin layer (B) described above are heated and melted by different extruders, and are in a molten state by a method such as a coextrusion multi-layer die method or a feed block method. Examples thereof include a coextrusion method in which the resin layer (A) / resin layer (B) / resin layer (A) are laminated in this order and then manufactured by the above processing method. This coextrusion method is preferable because the thickness ratio of each layer can be adjusted relatively freely, and a multilayer film having excellent hygiene and excellent cost performance can be obtained.

The easily tearable low-gloss film produced by the above manufacturing method does not require secondary processing such as a general stretching step for imparting easy tearability, and exhibits easy tearability only by film forming. Is a feature. This is, for example, when a film is formed by inflation molding with the above-mentioned specific raw material composition and layer structure, a cyclic olefin resin is stretched in the flow direction (MD) of the film to form a cooled and solidified dispersion structure. caused by. Therefore, since the viscosity of the cyclic olefin resin under the processing temperature during extrusion processing has a great influence on the dispersion structure, it is particularly necessary to select the optimum cyclic olefin resin according to the processing temperature. For example, when the processing temperature is about 170 ° C. to 230 ° C., the glass transition temperature of the cyclic olefin resin is more preferably 60 ° C. to 140 ° C.

The easily tearable low-gloss film of the present invention has low tear strength in both MD and TD, and can be made user-friendly such as easy opening. It is preferable that the Elmendorf tear strength is 20 N / mm or less for both MD and TD from the viewpoint of obtaining good tearability, and it is more preferable that the Elmendorf tear strength is 15 N / mm or less for both MD and TD. Elmendorf tear strength can be measured based on JIS K7128-2.

The easily tearable low-gloss film of the present invention has a low surface glossiness and can be used as a high-quality film having excellent design. The glossiness is preferably 10% or less, more preferably 5% or less in the measurement at the incident angle and the light receiving angle of 20 °. The glossiness can be measured based on JIS Z8741.

The easily tearable low-gloss film of the present invention has high impact strength and can be applied to various uses such as packaging bags and protective sheets. As for the impact strength, the impact strength at 70 μm in the dirt drop impact measurement is preferably 300 g or more, and more preferably 400 g or more from the viewpoint of strength. Impact strength can be measured based on JIS K7124.

3. 3. Packaging bag Examples of the packaging bag made of the easily tearable low-gloss film of the present invention include packaging bags and packaging containers used for foods, chemicals, medical instruments, industrial parts, miscellaneous goods, magazines, and the like.
Examples of the packaging bag include a packaging bag formed by superimposing and heat-sealing the inner layers or outer layers of the easily tearable low-gloss film of the present invention. Two films are cut out to the desired size of the packaging bag, and they are overlapped and heat-sealed on three sides to form a bag, and then the contents are filled from one side that is not heat-sealed. , It can be used as a packaging bag by heat-sealing and sealing. Further, one film can be used in the form of horizontal pillow packaging and vertical pillow packaging.

In the packaging material using the easily tearable low-gloss film of the present invention, any tear starting part such as V notch, I notch, perforation, microporous, etc. is provided in order to weaken the initial tear strength and improve the opening property. It is preferable to form it. Examples of the notch and the like forming portion include a sealing portion, upper and lower end portions of the packaging material, left and right fold portions, and a backing portion of pillow packaging. Depending on the form of the packaging material and the notch forming portion, the internal airtightness can be ensured by providing a sealing portion having a crescent shape or the like so as to surround the notch around the notch.
Further, examples of the packaging container include a deeply drawn molded product (bottom material having an opening at the top) obtained by secondary molding the film of the present invention, and a typical example is vacuum packaging for food use. Examples include the bottom material of the bag and the bottom material of the blister pack.
Examples of the above-mentioned secondary molding method include a vacuum forming method, a compressed air forming method, a vacuum pressurized air forming method, and the like. Among these, vacuum forming is preferable because the film or sheet can be molded in-line on the packaging machine and the contents can be filled.

In general, the flow direction (MD) of the packaging bag is an axis parallel to the line direction at the time of filling or bag making, and corresponds to the flow direction (MD) of the raw film. For example, in the case of a horizontal pillow packaging material, the long direction of the backing corresponds to the flow direction (MD) of the packaging bag and corresponds to the flow direction (MD) of the film.

4. Sheet Examples of the sheet made of the easily tearable low-gloss film of the present invention include protective sheets, release sheets, and low-reflection sheets used for applications such as foods, chemicals, medical devices, industrial parts, miscellaneous goods, magazines, and police forensics. ..
The sheet may be in the form of a tube film or a flat film, but is more preferably in the form of a flat film in actual use. The flat film in the present invention means a single film obtained by the T-die chill roll method or a single film obtained by slitting one end or both ends of a tubular film obtained by the inflation method.

As the sheet made of the easily tearable low-gloss film of the present invention, it is preferable that the above-mentioned copolymer (a) exhibiting low reflectivity is exposed on at least one outer layer surface of the sheet, and the layer structure is, for example, Examples thereof include a resin layer (A) / resin layer (B), a resin layer (A) / resin layer (B) / resin layer (A), and the like.
The sheet using the easily tearable low-gloss film of the present invention has an arbitrary tear start portion such as a V notch, an I notch, a perforation, or a microporous material in order to weaken the initial tear strength and improve the easy tearability. It is preferable to form it. Examples of the forming portion of the notch and the like include both ends of the seat and the like.

Examples and comparative examples of the present invention are shown below, and the present invention will be described in more detail, but the present invention is not limited to these examples.
(1) Raw material used (1-1) Copolymer (a)
-"Rexpearl (registered trademark) EMA" manufactured by Japan Polyethylene Corporation, MFR 2.0 g / 10 min, density 0.937 g / cm ³ ; ethylene-methyl acrylate copolymer (1-2) cyclic with MA content of 15 wt% Olefin resin (b)
-"TOPAS (registered trademark) 8007F-600" manufactured by Polyplastics Co., Ltd., ethylene-norbornene copolymer (1-3) polyolefin resin (c) with a glass transition temperature of 78 ° C.
-Nippon Polyethylene Co., Ltd. "Novatec (registered trademark) LD LF129", MFR 0.3 g / 10 min, density 0.922 g / cm ³ high-pressure method low-density polyethylene-Nippon Polyethylene Co., Ltd. "Novatec (registered trademark) LL UF320" , MFR 0.9g / 10min, density 0.922g / cm ³ linear low density polyethylene- "Novatec® LD LF240" manufactured by Nippon Polyethylene Co., Ltd., MFR 0.7g / 10min, density 0.924g / cm ³ High-pressure method low-density polyethylene-Nippon Polyethylene Co., Ltd. "Novatec (registered trademark) LL UF420", MFR 0.9 g / 10 min, linear low-density polyethylene with ^{a density of 0.924 g / cm 3}

(2) Inflation film forming (2-1) Multilayer film forming machine: 5 types, 5 layers Inflation forming machine Die diameter: 150 mmφ
Die lip clearance: 3mm
Processing temperature: 190 ° C
Layer ratio: 1 / 1.4 / 2.4 / 1.4 / 1
Blow ratio: 1.5
Pick-up speed: 10 m / min
Film thickness: 70 μm

(2-2) Single-layer film forming machine: Single-layer inflation forming machine Die diameter: 75 mmφ
Die lip clearance: 1mm
Processing temperature: 150 ° C
Blow ratio: 2.0
Pick-up speed: 15m / min
Film thickness: 50 μm

(3) Physical property evaluation method (3-1) Glossiness Based on JIS Z8741, measurement was performed with the following equipment and conditions. Before the measurement, calibration was performed with a black standard plate (angle 20 °, glossiness 87.8%).
Equipment: UGV-4D manufactured by Suga Test Instruments Co., Ltd.
Incident light angle: 20 °
Measurement environment: temperature 23 ° C, humidity 50%

(3-2) Elmendorf tear strength Based on JIS K7128-2, the Elmendorf tear strength was evaluated using the following equipment. MD is the film flow direction, and TD is the value in the vertical direction.
Equipment: Digital Elmendorf tear tester Model SA (manufactured by Toyo Seiki Seisakusho Co., Ltd.)
Measurement environment: temperature 23 ° C, humidity 50%

(3-3) Dirt drop impact strength Measured by method A based on JIS K7124.
Measurement environment: temperature 23 ° C, humidity 50%

(Example 1)
Using the above raw materials, an inflation film of 2 types and 5 layers laminated by the inflation molding method described in (2-1) above was obtained. The concentration of the cyclic olefin resin in the intermediate layer was 49% by weight. Table 1 shows the types of resins constituting each layer and their formulations.

(Example 2)
An inflation film was obtained in the same configuration as in Example 1 except that the copolymer (a) was blended in the intermediate layer of Example 1 at the concentrations shown in Table 1.

(Comparative Example 1)
Using "Novatec (registered trademark) LD LF240" manufactured by Japan Polyethylene Corporation instead of the copolymer (a), an inflation film of 2 types and 5 layers laminated by the inflation molding method described in (2-1) above was formed. Obtained. The concentration of the cyclic olefin resin in the intermediate layer was 49% by weight.

(Comparative Example 2)
Using "Novatec (registered trademark) LD LF240" manufactured by Japan Polyethylene Corporation for all layers, an inflation film of 1 type and 5 layers laminated by the inflation molding method described in (2-1) above was obtained. No cyclic olefin resin is used.

(Comparative Example 3)
Using "Novatec (registered trademark) LL UF420" manufactured by Japan Polyethylene Corporation for all layers, an inflation film of 1 type and 5 layers laminated by the inflation molding method described in (2-1) above was obtained. No cyclic olefin resin is used.

(Comparative Example 4)
Using the copolymer (a), a single-layer inflation film was obtained by the inflation molding method described in (2-2) above. No cyclic olefin resin is used.

For the single-layer or multilayer films obtained in each Example and Comparative Example, the glossiness, Elmendorf tear strength, and dirt drop impact strength were measured based on the methods described in (3-1) to (3-3) above. did. The results are listed in Table 1 below.

As is clear from Table 1, in Comparative Example 1, since the cyclic olefin resin is used for the intermediate layer, the tearability is excellent, but the low gloss property and the impact strength of the outer surface of the film are inferior. Further, in Comparative Example 2 and Comparative Example 3, since the cyclic olefin resin is not used, not only the tearability is inferior, but also the low gloss property and the impact strength are inferior. Since Comparative Example 4 uses a copolymer composed of ethylene and methyl acrylate, it is excellent in low gloss and impact strength, but because it does not use a cyclic olefin resin, it is inferior in tearability. On the other hand, in Examples 1 and 2, a copolymer composed of ethylene and methyl acrylate is used on both outer surfaces of the film, and a cyclic olefin resin is used in the intermediate layer, so that the outer surface of the film has low gloss. Not only is it excellent, but it is also excellent in tearability and impact strength. Therefore, it is suitable for films, packaging bags, sheets, etc. that require low gloss, easy tearability, and high impact strength.

Claims (15)

It is a single-layer or multi-layered easily tearable low-gloss film, and at least one of the layers contains a copolymer (a) containing ethylene and a functional group-containing monomer and a cyclic olefin resin (b). A characteristic easy-to-tear low-gloss film. The easily tearable low-gloss film according to claim 1, wherein the functional group-containing monomer is at least one selected from the group consisting of vinyl acetate, acrylic acid, acrylic acid ester, and maleic anhydride. A plurality of resins including at least two layers of a resin layer (A) containing the copolymer (a) as a main component and a resin layer (B) containing a cyclic olefin resin (b) and a polyolefin resin (c). The easily tearable low-gloss film according to claim 1 or 2, wherein the layers are laminated and the resin layer (A) is arranged at least in the outermost layer. The third aspect of the present invention is characterized in that the concentration of the cyclic olefin resin (b) in the resin layer (B) is 10 to 80% by weight, and the concentration of the polyolefin resin (c) is 20 to 90% by weight. The easily tearable low-gloss film described. The easily tearable low-gloss film according to claim 3 or 4, wherein the polyolefin-based resin (c) is a polyethylene-based resin. The easily tearable low-gloss film according to any one of claims 1 to 5, wherein the cyclic olefin resin (b) is an ethylene / cyclic olefin copolymer. The easily tearable low-gloss film according to claim 6, wherein the ethylene / cyclic olefin copolymer has a glass transition point of 60 ° C. or higher. The easily tearable low-gloss film according to any one of claims 1 to 7, further comprising a branched polyolefin in at least one of the layers. The easily tearable low-gloss film according to any one of claims 3 to 8, wherein the resin layer (A) further contains a branched polyolefin. The easily tearable low-gloss film according to any one of claims 1 to 9, wherein the tear strength of MD and TD measured by Elmendorf tear strength based on JIS K7128-2 is 20 N / mm or less. The method according to any one of claims 1 to 10, wherein the glossiness of at least one outermost layer surface of the film is 10% or less in the glossiness measurement at an incident angle and a light receiving angle of 20 ° based on JIS Z8741. Easy-to-tear low-gloss film. The easily tearable low-gloss film according to any one of claims 1 to 11, wherein the impact strength at 70 μm is 300 g or more in the dirt drop impact measurement based on JIS K7124. The easily tearable low-gloss film according to any one of claims 1 to 12, wherein the copolymer (a) is a copolymer composed of ethylene and methyl acrylate. A packaging bag using the easily tearable low-gloss film according to any one of claims 1 to 13. A sheet using the easily tearable low-gloss film according to any one of claims 1 to 13.