Thermoplastic resin film, decorative film, adhesive film, and adhesive film for semiconductor manufacturing process

Abstract

To provide a thermoplastic resin film which has sufficient adhesion with reduced influence of adhesion decrease over time, when the film requires adhesion to ink or an adhesive, and is also excellent in handleability and flexibility of the film, and appearance of the film.SOLUTION: A thermoplastic resin film includes at least two layers, wherein at least one layer contains 35 to 90 mass% of at least one selected from the group consisting of a modified polyethylene-based resin (A) and a modified polyethylene-based resin (B), and 10 to 65 mass% of a polyethylene-based resin other than the above polyethylene-based resins. Modified polyethylene-based resin (A): copolymer obtained by polymerizing ethylene and a (meth)acrylic monomer, in which more than 20 mass% of the (meth)acrylic monomer is contained in 100 mass% of the monomer constituting the copolymer. Modified polyethylene-based resin (B): modified polyethylene-based resin obtained by polymerizing ethylene, a (meth)acrylic monomer and a copolymerizable acid anhydride monomer.

Description

[Technical field]

[0001] The present invention relates to an adhesive film (tape) used in the semiconductor manufacturing process, a decorative adhesive film (tape) such as a sticker, label, or marking film attached to a signboard, automobile, or the like to impart a design, or a thermoplastic resin film that is suitably used as a substrate for a decorative film, etc., a decorative film comprising said film and a printed layer, and an adhesive film comprising said film and a pressure-sensitive adhesive layer. [Background technology]

[0002] Conventionally, films made of polyvinyl chloride resin (hereinafter also referred to as "PVC-based films"), which have excellent colorability, processability, scratch resistance, weather resistance, etc., have been widely used as the substrate for adhesive films (tapes) used in the semiconductor manufacturing process, decorative adhesive films (tapes) such as stickers, labels, and marking films attached to signs, automobiles, etc. to add design to them, decorative sheets, etc.

[0003] The PVC film itself has rigidity, but a plasticizer is added to impart flexibility so that the film can function as an adhesive film. However, depending on the plasticizer used, there are problems such as poor compatibility with the ink and adhesive used in printing, poor adhesion to the ink when a printed layer is laminated, and poor stability when used as an adhesive film, resulting in significant bleeding out of the plasticizer. There is also a tendency for the use of plasticizers to be more strictly regulated. Therefore, polyolefin resin films have come to be widely used as an alternative material to PVC films.

[0004] Even when a polyolefin resin film is used, the adhesion to inks and adhesives is poor, so methods such as corona treatment and atmospheric pressure plasma treatment are generally used. In addition, as a method for improving adhesion from the viewpoint of the resin used, a method of using an acrylic resin in combination with a polyolefin resin is sometimes used (for example, Patent Document 1). Furthermore, there is a technology that uses a polypropylene resin and a maleic anhydride modified polyolefin resin for the purpose of improving adhesion to pressure sensitive adhesives as a film for use in semiconductor manufacturing processes (eg, Patent Document 2).

[0005] However, surface modification using surface treatments such as corona treatment and atmospheric pressure plasma treatment has the problem that the effect of the surface treatment decreases over time. Furthermore, in the film described in Patent Document 1, the polyolefin resin and the acrylic resin have poor compatibility, and when the film is produced using a T-die, resin deposits called "me-ani" (sticky resin) adhere to the vicinity of the resin discharge port of the T-die, which makes it prone to the generation of foreign matter and streak-like defects resulting from the deposits, thereby deteriorating the appearance of the film. In the film described in Patent Document 2, the maleic anhydride modified resin uses a polyethylene resin, and since this resin is used in combination with a polypropylene resin, it is believed that the compatibility between the polypropylene resin and the polyethylene resin is insufficient. Therefore, there is room for improvement in improving the adhesion with the pressure-sensitive adhesive layer due to the insufficient compatibility, and there is a concern that the occurrence of eye scum due to the insufficient compatibility, similar to the phenomenon described in Patent Document 1, so there is also room for improvement in the appearance of the film. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent Publication No. 2021-75600 [Patent Document 2] JP 2022-177504 A DISCLOSURE OF THEINVENTION [Problem to be solved by the invention]

[0007] In view of the above problems, the present invention aims to provide a thermoplastic resin film that has sufficient adhesion with ink or adhesives, suppressing the effects of deterioration in adhesion over time, when the film is required to have good adhesion, and that also has excellent handleability, flexibility, and appearance. Another object of the present invention is to provide a decorative film, an adhesive film, and an adhesive film for use in semiconductor manufacturing processes by providing a printed layer or an adhesive layer on the thermoplastic resin film of the present invention. [Means for solving the problem]

[0008] The inventors have conducted extensive research into a thermoplastic resin film containing at least two layers, using a specific modified polyethylene resin for at least one of the thermoplastic resin surface layers constituting the front and back layers, thereby achieving a film that has adhesion to inks and adhesives, and is also excellent in handleability, flexibility, and appearance, and have completed the present invention.

[0009] That is, the gist of the present invention is as follows. [1] A thermoplastic film comprising at least two layers, The thermoplastic resin film is characterized in that at least one layer contains 35 to 90 mass% of at least one selected from the group consisting of modified polyethylene-based resin (A) and modified polyethylene-based resin (B), and 10 to 65 mass% of other polyethylene-based resin (wherein the total mass of the at least one selected from the group consisting of modified polyethylene-based resin (A) and modified polyethylene-based resin (B) and the other polyethylene-based resin is taken as 100 mass%). Modified polyethylene resin (A) A modified polyethylene resin is a copolymer obtained by polymerizing ethylene and a (meth)acrylic monomer, and contains more than 20% by mass of the (meth)acrylic monomer in 100% by mass of the monomers constituting the copolymer. Modified polyethylene resin (B) A modified polyethylene resin obtained by polymerizing ethylene, a (meth)acrylic monomer, and a copolymerizable acid anhydride monomer. [2] The thermoplastic resin film according to [1], wherein the (meth)acrylic monomer used in the modified polyethylene resin (A) and the modified polyethylene resin (B) is at least one selected from the group consisting of (meth)acrylic acid and (meth)acrylic acid alkyl esters. [3] The thermoplastic resin film according to [1] or [2], wherein the (meth)acrylic monomer used in the modified polyethylene resin (A) and the modified polyethylene resin (B) is a (meth)acrylic acid alkyl ester having an alkyl group having 1 to 4 carbon atoms. [4] The thermoplastic resin film according to any one of [1] to [3], wherein the thermoplastic resin film has a tensile modulus within a range of 100 to 600 MPa. [5] A cosmetic film comprising the thermoplastic resin film according to any one of [1] to [4], and a printed layer provided on at least one of the layers. [6] An adhesive film comprising the thermoplastic resin film according to any one of [1] to [4], and an adhesive layer provided on at least one of the layers. [7] The adhesive film for semiconductor manufacturing process according to [6], which is used in the semiconductor manufacturing process. Effect of the Invention

[0010] By using the modified polyethylene resin described in the present invention in a required content to produce a thermoplastic resin film, it is possible to provide a film that has sufficient adhesion even when adhesion to ink or adhesive is required, and also has excellent handleability and flexibility. In addition, by providing a printing layer or an adhesive layer on the thermoplastic resin film of the present invention, the thermoplastic resin film of the present invention can also be suitably used as a decorative film, an adhesive film, or an adhesive film for semiconductor manufacturing processes. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The present invention will be described in detail below, but the present invention is not limited to the following embodiments and can be modified and practiced in various ways within the scope of the gist. In addition, when the expression "~" is used in this specification, it is used as an expression including the numerical value or physical property value before and after it.

[0012] The thermoplastic resin film of the present invention is a thermoplastic resin film including at least two layers, characterized in that at least one layer contains 35 to 90 mass% of at least one selected from the group consisting of the modified polyethylene resin (A) and the modified polyethylene resin (B) described below, and contains 10 to 65 mass% of a polyolefin resin other than the modified polyethylene resin (A) and the modified polyethylene resin (B) (here, the total mass of the at least one selected from the group consisting of the modified polyethylene resin (A) and the modified polyethylene resin (B) and the other polyethylene resin is defined as 100 mass%). Modified polyethylene resin (A) A modified polyethylene resin is a copolymer obtained by polymerizing ethylene and a (meth)acrylic monomer, and contains more than 20% by mass of the (meth)acrylic monomer in 100% by mass of the monomers constituting the copolymer. Modified polyethylene resin (B) A modified polyethylene resin obtained by polymerizing ethylene, a (meth)acrylic monomer, and a copolymerizable acid anhydride monomer. In this specification, the at least one layer having a content of at least one selected from the group consisting of modified polyethylene resin (A) and the modified polyethylene resin (B) described below of 35 to 90 mass %, and a content of polyolefin resin other than modified polyethylene resin (A) and modified polyethylene resin (B) of 10 to 65 mass %, is also abbreviated as "layer (A)". The resins constituting the thermoplastic resin film of the present invention will be described in detail below.

[0013] <Modified polyethylene resin> The thermoplastic resin film of the present invention is a thermoplastic resin film including at least two layers, at least one of which contains at least one resin selected from the group consisting of modified polyethylene-based resin (A) and modified polyethylene-based resin (B). By containing at least one of the front and back layers a layer selected from the group consisting of modified polyethylene resin (A) and modified polyethylene resin (B), it is possible to improve the adhesion between the film and the printed layer or adhesive layer when an ink or adhesive is laminated onto the layer containing them. In this specification, the modified polyethylene resin (A) and the modified polyethylene resin (B) are collectively referred to as "modified polyethylene resin."

[0014] The modified polyethylene resin (A) is a copolymer obtained by polymerizing ethylene and a (meth)acrylic monomer, and in order to improve the adhesion described above, it is necessary for the copolymer to contain more than 20 mass% of a (meth)acrylic monomer in 100 mass% of the monomers constituting the copolymer. By incorporating the (meth)acrylic monomer in an amount of more than 20% by mass, it is possible to improve the adhesion of the resulting film to ink or adhesive, more preferably 22% by mass or more, and even more preferably 24% by mass or more.

[0015] The (meth)acrylic monomer used in the copolymerization is not particularly limited as long as it is a monomer copolymerizable with ethylene, but from the viewpoints of availability and ease of handling, it is preferable to use a (meth)acrylic acid alkyl ester having an alkyl group having 1 to 4 carbon atoms. In addition, the alkyl group may be either a straight-chain or a branched one. Specific examples of (meth)acrylic acid alkyl esters having an alkyl group having 1 to 4 carbon atoms include methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, methyl acrylate, ethyl acrylate, propyl acrylate, and butyl acrylate.

[0016] The modified polyethylene resin (B) is a modified polyethylene resin obtained by polymerizing ethylene, a (meth)acrylic monomer, and an acid anhydride monomer that can be copolymerized with them. Since it contains an acid anhydride monomer that can be copolymerized in addition to a (meth)acrylic monomer, it is possible to improve the adhesion between the film and ink or adhesive. The (meth)acrylic monomer used in the modified polyethylene resin (B) may be the same as that used in the modified polyethylene resin (A). The content of the (meth)acrylic monomer used in the copolymerization is preferably the same as that in the modified polyethylene resin (A). The acid anhydride monomer is not particularly limited, and commercially available products can be used. Specific examples of the acid anhydride monomer include maleic anhydride and itaconic anhydride. The content of the acid anhydride monomer used in copolymerization is preferably 0.1% by mass or more in 100% by mass of the monomers constituting the copolymer. By containing 0.1% by mass or more, it is possible to improve the adhesion between the obtained film and the ink or adhesive. It is more preferably 0.3% by mass or more, and even more preferably 0.5% by mass or more.

[0017] The crystalline melting peak of the modified polyethylene resin (A) and the modified polyethylene resin (B) is preferably 50°C or higher. By having a crystalline melting peak of 50°C or higher, it is possible to suppress the deterioration of the heat resistance of the obtained thermoplastic resin film, and further, when producing the film, it is possible to prevent the pellet-shaped resin from fusing with heat, making it easy to obtain the film. It is more preferably 55°C or higher, and even more preferably 60°C or higher. The crystalline melting peak can be measured using a differential scanning calorimeter according to "JIS K 7121".

[0018] The melt flow rate of the modified polyethylene resin (A) and the modified polyethylene resin (B) is appropriately selected depending on the molding method and application, but is preferably 0.1 to 50 g / 10 min measured at a temperature of 190 ° C. and a load of 2.16 kg. If it is 0.1 g / 10 min or more, the moldability of the film is good, and if it is 50 g / 10 min or less, the thickness precision of the film can be kept good. More preferably, it is 0.5 to 40 g / 10 min, and even more preferably, it is 1.0 to 30 g / 10 min. The method for measuring the melt flow rate can be the method described in "JIS K 7210". The conditions such as temperature and load during the measurement can be appropriately selected depending on the material used and its characteristics.

[0019] <Polyethylene resin> The thermoplastic resin film of the present invention is a thermoplastic resin film including at least two layers, and at least one of the layers contains a polyethylene resin other than the modified polyethylene resin (A) and the modified polyethylene resin (B) in the range of 10 to 65 mass %. The polyethylene resin that can be used is not particularly limited as long as it is other than the modified polyethylene resin (A) and the modified polyethylene resin (B), but from the standpoints of availability, ease of handling, ease of adjusting the physical properties of the resulting film, and compatibility with the modified polyethylene resin, examples include high-density polyethylene (HDPE), low-density polyethylene (LDPE), high-pressure low-density polyethylene, linear low-density polyethylene (LLDPE), ethylene copolymers obtained by polymerization using metallocene catalysts (metallocene polyethylene), ethylene-vinyl acetate copolymers, and metal ion crosslinked resins (ionomers) of ethylene-(meth)acrylic acid copolymers. Among the above-mentioned polyethylene resins, it is preferable to use high density polyethylene (HDPE), low density polyethylene (LDPE), high pressure low density polyethylene, and linear low density polyethylene (LLDPE) from the viewpoints of heat resistance, flexibility, availability, and the like.

[0020] As the high density polyethylene (HDPE), for example, a high density polyethylene composed of an ethylene homopolymer or a copolymer of ethylene and other monomers (hereinafter, other monomers) that are copolymerizable with ethylene, which is a main component, can be used. Examples of the other monomers include α-olefins having 3 or more carbon atoms. Examples of α-olefins having 3 or more carbon atoms include propylene, 1-butene, isobutene, 1-pentene, 2-methyl-butene, 3-methyl-1-butene, 1-hexene, 3-methyl-1-pentene, 4-methyl-1-pentene, 1-pentene, 1-octene, 1-decene, and 1-dodecene. From the viewpoint of availability of the monomer and the performance of the obtained high density polyethylene, it is preferable that the number of carbon atoms is within the range of 3 to 20, among those having 3 or more carbon atoms.

[0021] The density of high density polyethylene (HDPE) is 0.940 to 0.970 g / cm 3 It is preferable that the density is within the range of 0.940 to 0.970 g / cm 3 By using a high-density polyethylene within this range, it is easy to adjust the elastic modulus of the surface layer and / or back layer and intermediate layer of the obtained thermoplastic resin film. More preferably, it is 0.942 to 0.968 g / cm 3 and more preferably in the range of 0.944 to 0.966. Methods for measuring density include Method A (underwater displacement method), Method B (pycnometer method), Method C (floating-sink method), and Method D (density gradient tube method) described in "JIS K 7112". There are no particular limitations on the measurement method, and an appropriate method can be selected and used. The crystalline melting peak of high density polyethylene (HDPE) is preferably 120°C or higher. By having a crystalline melting peak of 120°C or higher, it is possible to impart sufficient heat resistance to the obtained thermoplastic resin film. It is more preferably 125°C or higher, and even more preferably 130°C or higher. The crystalline melting peak can be measured using a differential scanning calorimeter according to "JIS K 7121". Regarding the strength of high density polyethylene (HDPE), the tensile modulus of a film obtained solely from high density polyethylene is preferably within the range of 600 to 1800 MPa. If the tensile modulus is within the range of 600 to 1800 MPa, it is possible to impart appropriate strength and flexibility to the thermoplastic resin film of the present invention. More preferably, it is within the range of 650 to 1750 MPa, and further preferably within the range of 700 to 1700 MPa. The tensile modulus can be measured according to the method described in "JIS K 7127". Various conditions such as the shape of the test piece, the test speed, and the distance between chucks during measurement can be appropriately selected and used. The melt flow rate of high density polyethylene (HDPE) is appropriately selected depending on the molding method and application, but is preferably 0.1 to 50 g / 10 min measured at a temperature of 190° C. and a load of 2.16 kg. If it is 0.1 g / 10 min or more, the moldability of the film is good, and if it is 50 g / 10 min or less, the thickness precision of the film can be maintained at a good level. More preferably, it is 0.5 to 40 g / 10 min, and even more preferably, it is 1.0 to 30 g / 10 min. The method for measuring the melt flow rate can be the method described in "JIS K 7210". The conditions such as temperature and load during measurement can be appropriately selected depending on the material used and its characteristics. Commercially available high density polyethylene (HDPE) products include, for example, Novatec HD "HJ360", Novatec HD "HJ491", Novatec HD "HF560", Novatec HD "HY350" (all manufactured by Japan Polyethylene Co., Ltd.), Santech HD "B161", Santech HD "J340", Santech HD "J241" (all manufactured by Asahi Kasei Corporation), Nipolon Hard "4000", Nipolon Hard "2000", Nipolon Hard "2500", and Nipolon Hard "LW13D" (all manufactured by Tosoh Corporation). These high density polyethylenes (HDPE) may be used alone or in combination of two or more types. They can be appropriately selected as needed, taking into consideration the film forming properties when obtaining a thermoplastic resin film, the heat resistance and flexibility of the obtained film, and blocking between films.

[0022] As low density polyethylene (LDPE) and linear low density polyethylene (LLDPE), a high density polyethylene composed of an ethylene homopolymer or a copolymer of ethylene and other monomers (hereinafter, other monomers) that are copolymerizable with ethylene, which is a main component, can be used. Examples of the other monomers include α-olefins having 3 or more carbon atoms. Examples of the α-olefins having 3 or more carbon atoms include propylene, 1-butene, isobutene, 1-pentene, 2-methyl-butene, 3-methyl-1-butene, 1-hexene, 3-methyl-1-pentene, 4-methyl-1-pentene, 1-pentene, 1-octene, 1-decene, and 1-dodecene. From the viewpoint of availability of the monomer and the performance of the obtained high density polyethylene, it is preferable that the number of carbon atoms is within the range of 3 to 20, among the 3 or more.

[0023] The density of low-density polyethylene (LDPE) and linear low-density polyethylene (LLDPE) is 0.900 to 0.940 g / cm 3 It is preferable that the density is in the range of 0.900 to 0.940 g / cm 3 By using one within this range, it is easy to adjust the heat resistance and flexibility of the resulting thermoplastic resin film. More preferably, it is 0.902 to 0.938 g / cm 3 and more preferably in the range of 0.904 to 0.936. The density can be measured by the same method as described in the section on high density polyethylene. The crystalline melting peak of low density polyethylene (LDPE) and linear low density polyethylene (LLDPE) is preferably 70°C or higher. By having a crystalline melting peak of 70°C or higher, it becomes easy to adjust the heat resistance of the obtained thermoplastic resin film. It is more preferably 75°C or higher, and even more preferably 80°C or higher. The crystalline melting peak can be measured by the same method as described in the section on high density polyethylene. Regarding the strength of low density polyethylene (LDPE) and linear low density polyethylene (LLDPE), the tensile modulus of a film obtained from these resins alone is preferably within the range of 30 to 400 MPa. If the tensile modulus is within the range of 30 to 400 MPa, it is easy to adjust the flexibility of the thermoplastic resin film of the present invention. It is more preferably within the range of 40 to 350 MPa, and even more preferably within the range of 50 to 300 MPa. The tensile modulus can be measured by the same method as described in the section on high density polyethylene. The melt flow rate of low density polyethylene (LDPE) and linear low density polyethylene (LLDPE) is appropriately selected depending on the molding method and application, but the value measured under a temperature condition of 190°C and a load of 2.16 kg is preferably 0.1 to 50 g / 10 min. If it is 0.1 g / 10 min or more, the moldability of the film is good, and if it is 50 g / 10 min or less, the thickness precision of the film can be maintained at a good level. More preferably, it is 0.5 to 40 g / 10 min, and even more preferably, it is 1.0 to 30 g / 10 min. The method for measuring the melt flow rate can be the method described in "JIS K 7210". The conditions such as temperature and load during the measurement can be appropriately selected depending on the material used and its characteristics. Commercially available low-density polyethylene (LDPE) products include, for example, Novatec LD "LC500", Novatec LD "LC520", Novatec LD "LC720" (all manufactured by Japan Polyethylene Co., Ltd.), F224N, F324C, F522N (all manufactured by Ube Maruzen Polyethylene Co., Ltd.), and the like. Commercially available linear low-density polyethylene (LLDPE) products include, for example, Novatec LL "UF420" and Novatec LL "UF641" (both manufactured by Japan Polyethylene Co., Ltd.), Yumerit "0540F", and Yumerit "4040F" (both manufactured by Ube Maruzen Polyethylene Co., Ltd.).

[0024] <Other resins> As the resin used in the thermoplastic resin film of the present invention, in addition to the above-mentioned modified polyethylene resin (A), modified polyethylene resin (B), and polyethylene resin, other thermoplastic resins can be added within a range that does not impair heat resistance or flexibility. Examples of other thermoplastic resins include polypropylene resins, olefin elastomers, cyclic olefin resins, polymethylpentene resins, and styrene elastomers. Examples of polypropylene-based resins include homopolypropylene, random polypropylene, and block polypropylene, and an appropriate one can be selected and used taking into consideration the heat resistance, flexibility, and the like of the resulting film. The olefin-based elastomer is a soft resin containing a polyolefin-based resin and a rubber component, and may be one in which the rubber component is dispersed in the polyolefin-based resin, or one in which the two are copolymerized with each other. Specific examples of olefin-based elastomers include amorphous elastic copolymers mainly composed of olefins, such as ethylene-propylene copolymer elastomers, ethylene-1-butene copolymer elastomers, ethylene-propylene-1-butene copolymer elastomers, ethylene-1-hexene copolymer elastomers, ethylene-1-octene copolymer elastomers, ethylene-styrene copolymer elastomers, ethylene-norbornene copolymer elastomers, propylene-1-butene copolymer elastomers, ethylene-propylene-non-conjugated diene copolymer elastomers, ethylene-1-butene-non-conjugated diene copolymer elastomers, and ethylene-propylene-1-butene-non-conjugated diene copolymer elastomers, as well as derivatives and acid-modified derivatives thereof. Examples of cyclic olefin resins include norbornene polymers, vinyl alicyclic hydrocarbon polymers, and cyclic conjugated diene polymers. Among these, norbornene polymers are preferred. Examples of norbornene polymers include ring-opening polymers of norbornene monomers and norbornene copolymers obtained by copolymerizing norbornene monomers with α-olefins such as ethylene. Hydrogenated products of these may also be used. As the polymethylpentene-based resin, it is preferable to use a homopolymer having methylpentene as a monomer or a copolymer with other monomers.Specific examples include a copolymer of α-olefin and 4-methylpentene-1, which are exemplified as other monomers copolymerizable with propylene for the polypropylene-based resin. Examples of the styrene-based elastomer include block copolymers represented by the following formula (I) or (II). X-(YX)n …(I) (XY)n …(II) In general formulas (I) and (II), X is an aromatic vinyl polymer block (hereinafter, styrene component) typified by styrene, and in formula (I), the degree of polymerization at both ends of the molecular chain may be the same or different. Y is at least one selected from a butadiene polymer block, an isoprene polymer block, a butadiene / isoprene copolymer block, a hydrogenated butadiene polymer block, a hydrogenated isoprene polymer block, a hydrogenated butadiene / isoprene copolymer block, a partially hydrogenated butadiene polymer block, a partially hydrogenated isoprene polymer block, and a partially hydrogenated butadiene / isoprene copolymer block. n is an integer of 1 or more.

[0025] <Other ingredients> The thermoplastic resin film of the present invention may contain various additives in order to impart antistatic properties, heat resistance, weather resistance, and the like. Specific examples of the additives that may be used include antistatic agents, antioxidants, neutralizing agents, lubricants, antiblocking agents, plasticizers, heat stabilizers, light stabilizers, dyes and pigments, crystal nucleating agents, ultraviolet absorbers, fillers, and inorganic fillers that impart rigidity, as long as the effects of the present invention are not impaired. The polymer-type antistatic agent may be a known one, for example, a block copolymer of a hydrophobic block and a hydrophilic block. Examples of the polymer-type antistatic agent include a block copolymer formed by an ester bond, an ether bond, an amide bond, an imide bond, a urethane bond, a urea bond, or the like between the hydrophobic block and the hydrophilic block. As the ultraviolet absorbing agent, known agents can be used, and examples thereof include benzotriazole-based ultraviolet absorbing agents, benzophenone-based ultraviolet absorbing agents, and triazine-based ultraviolet absorbing agents. As the light stabilizer, a known one can be used, and examples thereof include hindered amine light stabilizers. As the lubricant or antiblocking agent, it is preferable to use a silicone-olefin copolymer, since this has excellent compatibility with the above-mentioned polypropylene-based resins, polyethylene-based resins, etc., and makes it possible to prevent defects due to bleed-out on the surface of the obtained film and to impart long-term scratch resistance and slipperiness.

[0026] <Thermoplastic resin film> The thermoplastic resin film of the present invention is a thermoplastic resin film including at least two layers, characterized in that at least one layer contains 35 to 90 mass% of at least one selected from the group consisting of modified polyethylene-based resin (A) and modified polyethylene-based resin (B), and 10 to 65 mass% of another polyethylene-based resin. Modified polyethylene resin (A) A modified polyethylene resin is a copolymer obtained by polymerizing ethylene and a (meth)acrylic monomer, and contains more than 20% by mass of the (meth)acrylic monomer in 100% by mass of the monomers constituting the copolymer. Modified polyethylene resin (B) A modified polyethylene resin obtained by polymerizing ethylene, a (meth)acrylic monomer, and a copolymerizable acid anhydride monomer.

[0027] The mass of the thermoplastic resin constituting at least one layer means the total mass of the modified polyethylene-based resin (A), the modified polyethylene-based resin (B), and the other polyethylene-based resins, and the content of the modified polyethylene-based resin (A), the modified polyethylene-based resin (B), and the other polyethylene-based resins is defined with the mass of the entire thermoplastic resin being 100 mass%. Here, the contents of the modified polyethylene resin (A), the modified polyethylene resin (B), and the other polyethylene resins in at least one layer can be specified as follows: the content of at least one selected from the group consisting of the modified polyethylene resin (A) and the modified polyethylene resin (B) is 35 to 90 mass%, and the content of the other polyethylene resins is 10 to 65 mass% (the total mass of the at least one selected from the group consisting of the modified polyethylene resin (A) and the modified polyethylene resin (B) and the other polyethylene resins is 100 mass%). By containing at least one selected from the group consisting of modified polyethylene resin (A) and modified polyethylene resin (B) in the range of 35 to 90 mass % in at least one layer, it becomes possible to improve adhesion to ink and adhesives when laminating them. By making it 35 mass % or more, it becomes possible to improve adhesion, and by making it 90 mass % or less, it becomes possible to suppress blocking between films, and further, it becomes easy to suppress defects such as the film wrapping around a cooling roll or a transport roll during film production. It is more preferably in the range of 40 to 85 mass %, and even more preferably in the range of 45 to 80 mass %. By containing the polyethylene resin other than the modified polyethylene resin (A) and the modified polyethylene resin (B) in the range of 10 to 65%, it is possible to improve the heat resistance and flexibility of the obtained film. By making it 10% by mass or more, it becomes easy to suppress blocking between the obtained films, and by making it 65% by mass or less, it becomes possible to suppress a significant decrease in adhesion to inks and adhesives. It is more preferably in the range of 15 to 60% by mass, and even more preferably in the range of 20 to 55% by mass.

[0028] The thermoplastic resin constituting at least one layer may contain other resins as required in addition to the modified polyethylene resin (A), modified polyethylene resin (B), and other polyethylene resins. When other resins are added, they may be used in an amount within the range of 0 to 30% by mass when the total amount of the thermoplastic resins contained in the at least one layer is taken as 100% by mass, within a range that does not impair physical properties such as adhesion to inks and adhesives, flexibility, and heat resistance. The amount is more preferably within the range of 0 to 25% by mass, and even more preferably within the range of 0 to 20% by mass. In addition, when the thermoplastic resin film has two layers, both layers may be the same or different. When an ink or adhesive is laminated on only one of the layers, it is preferable to have either one of the layers contain a modified polyethylene resin from the viewpoint of film formability and suppression of blocking between films, and when an ink or adhesive is laminated on both of the two layers, it is preferable to have both layers contain a modified polyethylene resin. In addition, when an ink or adhesive is laminated on both of the two layers, if the performance required for each layer is different, the type and content of the modified polyethylene resin can be different.

[0029] The thermoplastic resin film of the present invention may be configured to have three or more layers as required. In the case of three or more layers, one of the front and back layers may be specified to have a content of at least one selected from the group consisting of the modified polyethylene resin (A) and the modified polyethylene resin (B) of 35 to 90% by mass, and a content of other polyethylene resins of 10 to 65% by mass (the total mass of at least one selected from the group consisting of the modified polyethylene resin (A) and the modified polyethylene resin (B) and the other polyethylene resins is 100% by mass). The front and back layers may be the same or different. When an ink or adhesive is laminated on only one of the front and back layers, it is preferable to contain a modified polyethylene resin in either one of the layers from the viewpoint of film formability of the film and suppression of blocking between the films, and when an ink or adhesive is laminated on both the front and back layers, it is preferable to contain a modified polyethylene resin in both layers. Furthermore, when ink or adhesive is laminated to both layers, if the performance required for each layer is different, the type and content of the modified polyethylene resin can be different between the front layer and the back layer.

[0030] When the intermediate layer is made of three or more layers, it is preferable that the thermoplastic resin constituting the intermediate layer contains the thermoplastic resin used in the surface layer and the back layer, considering the adhesion between the layers. Therefore, it is more preferable to use a thermoplastic resin containing a modified polyethylene resin (A), a modified polyethylene resin (B), and other polyethylene resins. The mass of the entire thermoplastic resin constituting the intermediate layer means the total mass of the thermoplastic resins contained, and the content of each thermoplastic resin contained is specified with the mass of the entire thermoplastic resin being 100% by mass.

[0031] The thermoplastic resin constituting the intermediate layer preferably contains at least one selected from the group consisting of modified polyethylene resin (A) and modified polyethylene resin (B), in consideration of the interlayer adhesion with each of the front and back layers, and other polyethylene resins, and the contents thereof can be appropriately selected in consideration of the heat resistance, flexibility, and interlayer adhesion of the resulting film. The content of at least one selected from the group consisting of modified polyethylene resin (A) and modified polyethylene resin (B) is not particularly limited as long as it is a content that can improve the adhesion between the front layer and the back layer, but it is preferably in the range of 1 to 20 mass% when the total of the thermoplastic resins constituting the intermediate layer is 100 mass%. By containing 1 mass% or more, it is possible to improve the adhesion between each layer, and by containing 20 mass% or less, heat resistance and flexibility are not impaired, and it is also preferable from the viewpoint of the economic efficiency of the obtained film. It is more preferably in the range of 2 to 15 mass%, and even more preferably in the range of 3 to 10 mass%. The thermoplastic resin constituting the intermediate layer can contain other resins, as in the front and back layers. The content of the other resins is 0 to 40% by mass. When it is necessary to adjust the heat resistance or flexibility of the resulting film or to impart film formability, a suitable resin can be selected and used. The amount of the other resins used can be adjusted within a range that does not impair the heat resistance or flexibility, and the content is more preferably 0 to 30% by mass, and even more preferably 0 to 20% by mass. The intermediate layer may be composed of two or more layers. In this case, it is preferable from the viewpoint of maintaining adhesion between each layer that all layers of the intermediate layer composed of two or more layers contain the thermoplastic resin used in the front and back layers. From the viewpoint of film productivity and economic efficiency, it is preferably a two-layer film, and from the viewpoint of imparting performance to each layer of the film, it is more preferably a three-layer film composed of a front layer, a back layer, and one intermediate layer. When it is a three-layer film, whether it is a two-kind three-layer film in which the front layer and the back layer are composed of the same resin composition, or a three-kind three-layer film in which the front layer and the back layer are composed of different resin compositions can be appropriately selected as needed, taking into consideration the performance and use of each layer of the front and back of the film required, and the processability when providing a pressure-sensitive adhesive layer or a printing layer described later.

[0032] The total thickness of the thermoplastic resin film of the present invention is preferably 30 to 250 μm. If it is 30 μm or more, the film formability during film production and the handleability of the obtained film are good, and flexibility and heat resistance can be maintained good, and if it is 250 μm or less, the handleability and processability of the film in the step of laminating a printing layer and a pressure-sensitive adhesive layer on the film can be maintained good. The total thickness of the thermoplastic resin film of the present invention is more preferably 40 to 230 μm, and further preferably 50 to 210 μm. In the case of a two-layer structure, the thickness of one layer containing the modified polyethylene resin (A), the modified polyethylene resin (B), and other polyethylene resins is preferably within the range of 1 to 50% of the total thickness. By making it 1% or more, it becomes possible to fully exhibit adhesion between the film and a printed layer or an adhesive layer when the layer is laminated, and by making it 50% or less, it is preferable from the viewpoint of film formability and economic efficiency. It is more preferably within the range of 3 to 40%, and even more preferably within the range of 5 to 30%. The thickness of each of the front layer and the back layer in the case of a three or more layer structure is preferably within the range of 1 to 30% of the total thickness of the thermoplastic resin film. By making it 1% or more of the total thickness, it is possible to fully express the adhesion between the printed layer and the adhesive layer when they are laminated, and by making it 30% or less, it is easy to adjust the film formability and flexibility of the obtained film, which is also preferable from the viewpoint of the economic efficiency of the obtained film. More preferably, it is within the range of 3 to 25%, and even more preferably within the range of 5 to 20%. The thickness of each of the front layer and the back layer may be the same thickness or may be different thicknesses as long as it can suppress the performance required for each of the front layer and the back layer of the obtained thermoplastic resin film and the blocking between the films. From the viewpoint of the productivity and economic efficiency of the film, it is preferable that the thickness of the front layer and the back layer are the same. The thickness of the intermediate layer is appropriately determined according to the thickness of the front layer and the back layer, and in the case of a multi-layer film having two or more intermediate layers, the thickness of each layer can be appropriately determined according to the film formability and the required performance of the obtained film.

[0033] The tensile modulus of the thermoplastic resin film of the present invention is preferably within the range of 100 to 600 MPa. If it is 100 MPa or more, the film is not too flexible and can maintain good handleability, and if it is 600 MPa or less, the flexibility of the film is not impaired and the film can maintain good handleability and processability in the process of laminating a printing layer and a pressure-sensitive adhesive layer on the film. It is more preferably within the range of 120 to 550 MPa, and even more preferably within the range of 140 to 500 MPa.

[0034] The tensile elongation at break of the thermoplastic resin film of the present invention is preferably 300% MPa or more. If the tensile elongation at break is 300% or more, breakage during handling of the film is suppressed, and therefore defects due to breakage are suppressed even when adhesive processing or the like is performed, and breakage during expansion is less likely to occur in the expansion step in the semiconductor manufacturing process, which is preferable. It is more preferably 400% or more, and even more preferably 500% or more. The tensile modulus and breakage elongation can be measured by the same method as described in the section on high density polyethylene.

[0035] The thermoplastic resin film of the present invention can be formed by any known method, but it is preferable to use a melt extrusion method. Among the melt extrusion methods, a T-die molding method in which a molten resin is extruded from an extruder having a T-die and cooled and solidified to obtain a film is more preferable. In order to obtain a film, it is preferable to use a co-extrusion T-die molding method using a plurality of extruders. By using a co-extrusion T-die molding method using a plurality of extruders, it is possible to obtain a multi-layer film, and it is possible to obtain a film containing at least two layers of the present invention. In addition, it is also possible to obtain the above-mentioned two-kind three-layer, three-kind three-layer, or an intermediate layer consisting of two or more multilayers.

[0036] Examples of coextrusion T-die molding methods include a method in which multiple resin layers are formed into a film using a multi-manifold die, and then the layers are brought into contact inside the T-die to form a multi-layered film; and a method in which multiple resins are joined and bonded together using a device that joins molten resins called a feed block, to obtain a multi-layered film.

[0037] The resin extruded in a molten state from the T-die can be cooled and solidified by contacting it with a cooling roll set at a predetermined temperature. The set temperature of the cooling roll is not particularly limited, but it is preferably set to 80°C or less. If it is 80°C or less, it is possible to suppress the phenomenon that the molten resin remains stuck to the cooling roll and cannot be peeled off. It is more preferably 70°C or less, and even more preferably 60°C or less. Furthermore, the surface temperature of the cooling roll is preferably 100°C or less from the viewpoint of suppressing defects caused by the same film sticking. When using a molding method using a rubber roll or metal roll and a nip as described later, it is preferable to adjust the temperature setting and surface temperature of these rolls to be approximately the same as that of the cooling roll. The method for adhering the film to the cooling roll is not particularly limited, and examples thereof include an air knife, an air chamber, electrostatic pinning, and a nip between a rubber roll or a metal roll.

[0038] The thermoplastic resin film of the present invention contains a predetermined amount of at least one selected from the group consisting of modified polyethylene resin (A) and modified polyethylene resin (B) in at least one layer, and therefore has sufficient adhesion to the printed layer and the pressure-sensitive adhesive layer, but if necessary, one or both sides of the film may be subjected to a surface treatment by a method such as plasma treatment, corona treatment, ozone treatment, and flame treatment. From the viewpoint of the use of the obtained film and the prevention of blocking between films, it is possible to select whether to perform a surface treatment on one or both sides, or to perform no corona treatment on either side. However, since the effects of surface treatments such as the above-mentioned plasma treatment and corona treatment decrease over time, it is preferable not to perform a surface treatment on the film of the present invention from the viewpoint of suppressing changes in surface performance over time.

[0039] <Decorative film> The thermoplastic resin film of the present invention can be made into a decorative film by providing a printed layer on at least one of the above-mentioned layers (layer (A)) (hereinafter also referred to as "the decorative film of the present invention"). The ink used for the printing layer is not particularly limited, but for example, acrylic resin, urethane resin, vinyl chloride resin, etc. are used. The printed layer constituting the decorative film can be formed by a known method. For example, known printing methods such as offset printing, gravure rotary printing, and screen printing, known coating methods such as roll coating and spray coating, and flexographic printing can be used. Vapor deposition can also be used. Examples of print patterns include wood grain, stone grain, cloth grain, sand grain, geometric patterns, letters, full solid patterns, metallic patterns, and the like. The thickness of the printing layer can be appropriately determined according to need. Furthermore, a primer layer may be provided between the film (layer (A)) and the printed layer, if necessary. The thickness of the printing layer and the primer layer can be appropriately determined according to need.

[0040] <Adhesive film> The thermoplastic resin film of the present invention can be made into an adhesive film by providing an adhesive layer on at least one layer (hereinafter also referred to as "adhesive film of the present invention"). The adhesive used in the adhesive layer is not particularly limited, and various adhesives such as natural rubber resins, acrylic resins, styrene resins, silicone resins, polyvinyl ether resins, etc. may be used. In addition, a functional layer such as an adhesive layer or a thermosetting resin layer may be further provided on the adhesive layer.

[0041] The pressure-sensitive adhesive layer can be provided by directly coating the pressure-sensitive adhesive on the thermoplastic resin film of the present invention, or by laminating the pressure-sensitive adhesive layer on a separator or the like having a release layer, attaching the pressure-sensitive adhesive layer side of the separator to the surface layer of the film of the present invention, and transferring the pressure-sensitive adhesive layer. In the pressure-sensitive adhesive film of the present invention, one or both sides of the film before the pressure-sensitive adhesive layer is provided may be subjected to the above-mentioned surface treatment. In addition, a primer layer may be provided between the film (layer (A)) and the pressure-sensitive adhesive layer, if necessary. The thickness of the adhesive layer and the primer layer can be appropriately determined according to need.

[0042] The thermoplastic resin film of the present invention uses a specific thermoplastic resin in at least one layer, and as a result, the film has excellent adhesion to inks and adhesives, as well as excellent heat resistance, handleability, and flexibility. Furthermore, by laminating a printed layer or an adhesive layer onto the film, a decorative film or an adhesive film can be obtained. The adhesive film can be suitably used for the decorative application of various materials, and for use in the semiconductor manufacturing process. EXAMPLES

[0043] The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to these examples. The materials used in the following examples and comparative examples and the methods for measuring the evaluated properties are as follows.

[0044] [Materials used] As the thermoplastic resins, high density polyethylene, low density polyethylene, and various modified polyethylene resins were used as shown below.

[0045] <High density polyethylene> "HF560" manufactured by Japan Polyethylene Corporation (high density polyethylene, melt flow rate at 190°C and 2.16 kg: 7.0 g / 10 min, crystal melting peak: 134°C, density: 0.963 g / cm 3 , Tensile modulus of single film: 1000MPa) <Low density polyethylene> "Novatec LC500" manufactured by Japan Polyethylene Corporation (low density polyethylene, melt flow rate at 190°C and 2.16 kg: 4.0 g / 10 min, crystal melting peak: 106°C, tensile modulus of single film: 140 MPa)

[0046] <Modified polyethylene resin (A-1)> Sumitomo Chemical Co., Ltd., "Acryft WK307" (ethylene-methyl methacrylate copolymer (methyl methacrylate content: 25% by mass), melt flow rate at 190°C and 2.16 kg: 7.0 g / 10 min, crystalline melting peak: 80°C) <Modified polyethylene resin (A-2)> Sumitomo Chemical Co., Ltd., "Acryft WK402" (ethylene-methyl methacrylate copolymer (methyl methacrylate content: 25% by mass), melt flow rate at 190°C and 2.16 kg: 20.0 g / 10 min, crystalline melting peak: 79°C) <Modified polyethylene resin (A-3)> Sumitomo Chemical Co., Ltd., "Acryft WK401-F" (ethylene-methyl methacrylate copolymer (methyl methacrylate content: 20% by mass), melt flow rate at 190°C and 2.16 kg: 20.0 g / 10 min, crystalline melting peak: 86°C) <Modified polyethylene resin (A-4)> Dow Mitsui Polychemicals' "Nucrel N0903HC" (ethylene-methacrylic acid copolymer (methacrylic acid content: 9% by mass), melt flow rate of 3.0 g / 10 min at 190°C and 2.16 kg, crystal melting peak: 99°C) <Modified polyethylene resin (B)> SK Functional Polymer's "BONDINE AX8390" (ethylene-ethyl acrylate-maleic anhydride copolymer (ethyl acrylate content: 29% by mass, maleic anhydride content: 1.3% by mass), melt flow rate at 190°C and 2.16 kg: 7.0 g / 10 min, crystalline melting peak: 65°C)

[0047] <Preparation of Resin Composition> The above thermoplastic resins were mixed for the front layer, middle layer, and back layer so that the total amount was 100 parts by mass, as shown in Table 1. When two or more types were used, they were mixed by dry blending, and it was confirmed by visual inspection that the mixture was uniform.

[0048] <Film production method> Each resin composition was charged into each hopper of three Toshiba Machine single-screw extruders (surface layer: 35φmm, L / D=25mm, middle layer: 50φmm, L / D=32, back layer: 35φmm, L / D=25mm), the extruder temperature of each extruder was set to 190-230°C, and the three-layer structure of surface layer / middle layer / back layer was merged in the feed block section and extruded from a 650mm wide T-die (temperature setting 210-230°C, lip opening 0.5mm). The rotation speed of each extruder was set so that the thickness configuration was as shown in Table 1. The extruded molten resin was nipped between a matte (surface roughness Ra approximately 1.0 μm) metal cooling roll (metal cooling roll: 700 mm width x φ350 mm) through which cooling water set at 30°C had been passed, and a matte (surface roughness Ra approximately 1.0 μm) rubber cooling roll (rubber cooling roll: 700 mm width x φ200 mm) through which the resin was cooled and solidified into a film. The film was then taken up on a winding machine to obtain a three-type, three-layer film with a thickness of approximately 80 μm. In the present invention, the surface of the obtained film facing the metallic cooling roll is expressed as the surface layer.

[0049] [Film formability] When a film was produced by the above-mentioned film-forming method, the adhesion of the film to a rubber cooling roll or a metal cooling roll was evaluated according to the following criteria. 〇: No film sticking to the roll ×: The film wraps around the roll or sticks to the roll, making it difficult to peel off.

[0050] [Thickness of each layer] The thickness of each layer was calculated from the amount of resin extruded from each extruder. [Total film thickness] The thickness of the film was measured at the center and both ends using a contact thickness meter to confirm that the film had the desired thickness.

[0051] [Tensile modulus] Test pieces were prepared from the obtained thermoplastic resin film using a dumbbell "SDK-600" manufactured in accordance with JIS K6732, and the tensile modulus (MPa) was measured at a tension speed of 50 mm / min using an autograph (Shimadzu Corporation AGS-X) under the following conditions referring to JIS K7127, under an atmosphere of 23°C and 50% RH. The tensile modulus was measured in the extrusion direction (MD) of the film.

[0052] [Tensile elongation at break] Test pieces were taken from the obtained film using a dumbbell "SDK-600" manufactured in accordance with JIS K6732, and the tensile breaking elongation (%) was measured at a tensile speed of 300 mm / min using a small tabletop testing machine (Shimadzu EZ-L) in an atmosphere of 23°C and 50% RH. The tensile elongation at break was measured in the extrusion direction (MD) of the film.

[0053] [Ink adhesion] The ink for vinyl cosmetic films manufactured by DIC Graphics Co., Ltd. described below was applied to the surface side of the film using the gravure printing tester "GP-2" and the printing plate "54L gradation" manufactured by Kurashiki Boseki Co., Ltd. The film after application was aged at 40°C for 5 days to obtain a cosmetic film with a printed layer formed by the ink. A cellophane tape was attached to the printed layer of the obtained cosmetic film and peeled off, and the adhesion between the printed layer and the film was evaluated according to the following criteria. ◎: All inks of 6 gradations remain, and no peeling is observed. 〇: Inks of 4 - 5 gradations remain, and peeling of 1 - 2 gradations is observed. △: Inks of 2 - 3 gradations remain, and peeling of 3 - 4 gradations is observed. ×: The remaining ink is below 1 gradation or there is no remaining ink due to the destruction of the base material. <Ink for Vinyl Cosmetic Films Manufactured by DIC Graphics Co., Ltd.> 95 parts by mass of "VTP-NT40 Yellow (A)" and 5 parts by mass of "AT-NT Solvent" were used, and they were mixed and stirred to prepare the ink.

[0054] [Example 1] As the thermoplastic resins for the surface layer, intermediate layer, and back layer, high-density polyethylene, low-density polyethylene, modified polyethylene-based resin (A-1), and modified polyethylene-based resin (B) were used in the blending amounts shown in Table 1, and resin compositions for each layer were prepared. Using the above resin compositions for the surface layer, intermediate layer, and back layer, a film with a total thickness of 80 μm composed of 3 types and 3 layers was obtained by a nip forming manufacturing method using the above-mentioned matte metal cooling roll and matte silicone rubber roll. The thickness of each layer was adjusted so that the surface layer was 4 μm, the intermediate layer was 64 μm, and the back layer was 12 μm, and no surface treatment such as corona treatment was applied to this film. Also, when observing the vicinity of the die outlet of the T-die when collecting the film, no adhesion of fish eyes was observed in the vicinity of the die outlet, and no abnormality was observed in the film appearance. Thus, it was confirmed that the film had a good appearance. The film consisting of the above surface layer, intermediate layer and back layer had a tensile modulus of 340 MPa and a tensile breaking elongation of 930%, confirming that it had sufficient flexibility and breaking properties. Furthermore, when the adhesion of the ink applied to the surface of this film was tested, no peeling was observed in any of the six gradations, demonstrating excellent adhesion, confirming that this is a film with good adhesion. Therefore, it was confirmed that the present film is excellent in handleability and flexibility, and has good adhesion to ink even without surface treatment such as corona treatment.

[0055] [Example 2] As the thermoplastic resins for the surface layer, intermediate layer and back layer, high density polyethylene, low density polyethylene and modified polyethylene resin (A-1) were used in the amounts shown in Table 1 to prepare resin compositions for each layer. Using the above resin compositions for the surface layer, intermediate layer, and back layer, a film consisting of three types and three layers and having a total thickness of 80 μm was obtained by the manufacturing method using the above matte metal cooling roll and matte silicone rubber roll by nip molding. The film-forming conditions were adjusted so that the thickness of each layer was 4 μm for the surface layer, 64 μm for the intermediate layer, and 12 μm for the back layer, and this film was not subjected to surface treatment such as corona treatment. In addition, when the vicinity of the discharge outlet of the T-die was observed while the film was being collected, no adhesion of resin was found near the discharge outlet, and no abnormalities were observed in the appearance of the film, confirming that the film had a good appearance. The film consisting of the above surface layer, intermediate layer and back layer had a tensile modulus of 360 MPa and a tensile breaking elongation of 930%, confirming that it had sufficient flexibility and breaking properties. Furthermore, when the adhesion of the ink applied to the surface of this film was tested, no peeling was observed in any of the six gradations, demonstrating excellent adhesion, confirming that this is a film with good adhesion. Therefore, it was confirmed that the present film is excellent in handleability and flexibility, and has good adhesion to ink even without surface treatment such as corona treatment.

[0056] [Example 3] As the thermoplastic resins for the front layer, middle layer and back layer, high density polyethylene, low density polyethylene, modified polyethylene resin (A-2) and modified polyethylene resin (B) were used in the amounts shown in Table 1 to prepare resin compositions for each layer. Using the above resin compositions for the surface layer, intermediate layer, and back layer, a film consisting of three types and three layers and having a total thickness of 80 μm was obtained by the manufacturing method using the above matte metal cooling roll and matte silicone rubber roll by nip molding. The film-forming conditions were adjusted so that the thickness of each layer was 4 μm for the surface layer, 64 μm for the intermediate layer, and 12 μm for the back layer, and this film was not subjected to surface treatment such as corona treatment. In addition, when the vicinity of the discharge outlet of the T-die was observed while the film was being collected, no adhesion of resin was found near the discharge outlet, and no abnormalities were observed in the appearance of the film, confirming that the film had a good appearance. The film consisting of the above surface layer, intermediate layer and back layer had a tensile modulus of 360 MPa and a tensile breaking elongation of 890%, confirming that it had sufficient flexibility and breaking properties. Furthermore, in testing the adhesion of the ink applied to the surface of this film, peeling of 1-2 gradations was observed, but 4-5 gradations of ink remained, confirming that the film has sufficient adhesion to the ink. Therefore, it was confirmed that the present film is excellent in handleability and flexibility, and has good adhesion to ink even without surface treatment such as corona treatment.

[0057] [Example 4] As the thermoplastic resins for the surface layer, intermediate layer and back layer, high density polyethylene, low density polyethylene and modified polyethylene resin (A-2) were used in the amounts shown in Table 1 to prepare resin compositions for each layer. Using the above resin compositions for the surface layer, intermediate layer, and back layer, a film consisting of three types and three layers and having a total thickness of 80 μm was obtained by the manufacturing method using the above matte metal cooling roll and matte silicone rubber roll by nip molding. The film-forming conditions were adjusted so that the thickness of each layer was 4 μm for the surface layer, 64 μm for the intermediate layer, and 12 μm for the back layer, and this film was not subjected to surface treatment such as corona treatment. In addition, when the vicinity of the discharge outlet of the T-die was observed while the film was being collected, no adhesion of resin was found near the discharge outlet, and no abnormalities were observed in the appearance of the film, confirming that the film had a good appearance. The film consisting of the above surface layer, intermediate layer and back layer had a tensile modulus of 380 MPa and a tensile breaking elongation of 920%, confirming that it had sufficient flexibility and breaking properties. Furthermore, when the adhesion of the ink applied to the surface of this film was tested, no peeling was observed in any of the six gradations, demonstrating excellent adhesion, confirming that this is a film with good adhesion. Therefore, it was confirmed that the present film is excellent in handleability and flexibility, and has good adhesion to ink even without surface treatment such as corona treatment.

[0058] [Example 5] As the thermoplastic resins for the surface layer, intermediate layer and back layer, high density polyethylene, low density polyethylene and modified polyethylene resin (A-1) were used in the amounts shown in Table 1 to prepare resin compositions for each layer. Using the above resin compositions for the surface layer, intermediate layer, and back layer, a film consisting of three types and three layers and having a total thickness of 80 μm was obtained by the manufacturing method using the above matte metal cooling roll and matte silicone rubber roll by nip molding. The film-forming conditions were adjusted so that the thickness of each layer was 4 μm for the surface layer, 64 μm for the intermediate layer, and 12 μm for the back layer, and this film was not subjected to surface treatment such as corona treatment. In addition, when the vicinity of the discharge outlet of the T-die was observed while the film was being collected, no adhesion of resin was found near the discharge outlet, and no abnormalities were observed in the appearance of the film, confirming that the film had a good appearance. The film consisting of the above surface layer, intermediate layer and back layer had a tensile modulus of 340 MPa and a tensile breaking elongation of 910%, confirming that it had sufficient flexibility and breaking properties. Furthermore, when the adhesion of the ink applied to the surface of this film was tested, no peeling was observed in any of the six gradations, demonstrating excellent adhesion, confirming that this is a film with good adhesion. Therefore, it was confirmed that the present film is excellent in handleability and flexibility, and has good adhesion to ink even without surface treatment such as corona treatment.

[0059] [Example 6] As the thermoplastic resins for the surface layer, intermediate layer and back layer, high density polyethylene, low density polyethylene and modified polyethylene resin (A-1) were used in the amounts shown in Table 1 to prepare resin compositions for each layer. Using the above resin compositions for the surface layer, intermediate layer, and back layer, a film consisting of three types and three layers and having a total thickness of 80 μm was obtained by the manufacturing method using the above matte metal cooling roll and matte silicone rubber roll by nip molding. The film-forming conditions were adjusted so that the thickness of each layer was 4 μm for the surface layer, 64 μm for the intermediate layer, and 12 μm for the back layer, and this film was not subjected to surface treatment such as corona treatment. In addition, when the vicinity of the discharge outlet of the T-die was observed while the film was being collected, no adhesion of resin was found near the discharge outlet, and no abnormalities were observed in the appearance of the film, confirming that the film had a good appearance. The film consisting of the above surface layer, intermediate layer and back layer had a tensile modulus of 370 MPa and a tensile breaking elongation of 900%, confirming that it had sufficient flexibility and breaking properties. In testing the adhesion of the ink on the surface of this film, peeling was observed in 3 to 4 gradations and ink remained in 2 to 3 gradations because the content of the added modified polyethylene resin (A-1) was low within the specified range, and it was found that the film had good adhesion, although not sufficient. Therefore, it was confirmed that the present film is excellent in handleability and flexibility, and has good adhesion to ink even without surface treatment such as corona treatment.

[0060] [Comparative Example 1] As the thermoplastic resins for the surface layer, intermediate layer and back layer, high density polyethylene, low density polyethylene and modified polyethylene resin (B) were used in the amounts shown in Table 1 to prepare resin compositions for each layer. Using the above resin compositions for the surface layer, intermediate layer, and back layer, a film consisting of three types and three layers and having a total thickness of 80 μm was obtained by the manufacturing method using the above matte metal cooling roll and matte silicone rubber roll by nip molding. The film-forming conditions were adjusted so that the thickness of each layer was 4 μm for the surface layer, 64 μm for the intermediate layer, and 12 μm for the back layer, and this film was not subjected to surface treatment such as corona treatment. In addition, when the vicinity of the discharge outlet of the T-die was observed while the film was being collected, no adhesion of resin was found near the discharge outlet, and no abnormalities were observed in the appearance of the film, confirming that the film had a good appearance. The film consisting of the above-mentioned surface layer, intermediate layer and back layer had a tensile modulus of 360 MPa and a tensile breaking elongation of 900%, confirming that it had sufficient flexibility and breaking properties. However, in the test of the adhesion of the ink applied to the surface side of this film, the content of the added modified polyethylene resin (B) was 30 mass%, which was less than the specified content range, and therefore the remaining ink was about one gradation or less, and it was recognized that the film had poor adhesion to the ink. Therefore, it was confirmed that although this film has excellent handling properties and flexibility, it has poor adhesion to ink unless surface treatment such as corona treatment is performed.

[0061] [Comparative Example 2] As the thermoplastic resins for the surface layer, intermediate layer and back layer, high density polyethylene, low density polyethylene and modified polyethylene resin (A-1) were used in the amounts shown in Table 1 to prepare resin compositions for each layer. Using the above resin compositions for the surface layer, intermediate layer, and back layer, a film consisting of three types and three layers and having a total thickness of 80 μm was obtained by the manufacturing method using the above matte metal cooling roll and matte silicone rubber roll by nip molding. The film-forming conditions were adjusted so that the thickness of each layer was 4 μm for the surface layer, 64 μm for the intermediate layer, and 12 μm for the back layer, and this film was not subjected to surface treatment such as corona treatment. In addition, when the vicinity of the discharge outlet of the T-die was observed while the film was being collected, no adhesion of resin was found near the discharge outlet, and no abnormalities were observed in the appearance of the film, confirming that the film had a good appearance. The film consisting of the above surface layer, intermediate layer and back layer had a tensile modulus of 380 MPa and a tensile breaking elongation of 860%, confirming that it had sufficient flexibility and breaking properties. However, in the test for the adhesion of the ink applied to the surface side of this film, the content of the added modified polyethylene resin (A-1) was 30 mass%, which was less than the specified content range, and therefore the remaining ink was about one gradation or less, and it was recognized that the film had poor adhesion to the ink. Therefore, it was confirmed that although this film has excellent handling properties and flexibility, it has poor adhesion to ink unless surface treatment such as corona treatment is performed.

[0062] [Comparative Example 3] As the thermoplastic resins for the surface layer, intermediate layer and back layer, high density polyethylene, low density polyethylene and modified polyethylene resin (A-3) were used in the amounts shown in Table 1 to prepare resin compositions for each layer. Using the above resin compositions for the surface layer, intermediate layer, and back layer, a film consisting of three types and three layers and having a total thickness of 80 μm was obtained by the manufacturing method using the above matte metal cooling roll and matte silicone rubber roll by nip molding. The film-forming conditions were adjusted so that the thickness of each layer was 4 μm for the surface layer, 64 μm for the intermediate layer, and 12 μm for the back layer, and this film was not subjected to surface treatment such as corona treatment. In addition, when the vicinity of the discharge outlet of the T-die was observed while the film was being collected, no adhesion of resin was found near the discharge outlet, and no abnormalities were observed in the appearance of the film, confirming that the film had a good appearance. The film consisting of the above surface layer, intermediate layer and back layer had a tensile modulus of 360 MPa and a tensile breaking elongation of 950%, confirming that it had sufficient flexibility and breaking properties. However, although the content of the modified polyethylene resin (A-3) used on the surface side of this film was 60% by mass, which was within the specified content range, the content of the (meth)acrylic monomer in 100% by mass of the monomers constituting the modified polyethylene resin (A-3) was 20% by mass, which did not exceed 20% by mass. Therefore, in the test of the adhesion of the ink applied to the surface side of this film, the remaining ink was about one gradation or less, and it was recognized that the film had poor adhesion to ink. Therefore, it was confirmed that although this film has excellent handling properties and flexibility, it has poor adhesion to ink unless surface treatment such as corona treatment is performed.

[0063] [Comparative Example 4] As the thermoplastic resins for the surface layer, intermediate layer and back layer, high density polyethylene, low density polyethylene and modified polyethylene resin (A-4) were used in the amounts shown in Table 1 to prepare resin compositions for each layer. Using the above resin compositions for the surface layer, intermediate layer, and back layer, a film consisting of three types and three layers and having a total thickness of 80 μm was obtained by the manufacturing method using the above matte metal cooling roll and matte silicone rubber roll by nip molding. The film-forming conditions were adjusted so that the thickness of each layer was 4 μm for the surface layer, 64 μm for the intermediate layer, and 12 μm for the back layer, and this film was not subjected to surface treatment such as corona treatment. In addition, when the vicinity of the discharge outlet of the T-die was observed while the film was being collected, no adhesion of resin was found near the discharge outlet, and no abnormalities were observed in the appearance of the film, confirming that the film had a good appearance. The film consisting of the above surface layer, intermediate layer and back layer had a tensile modulus of 370 MPa and a tensile breaking elongation of 930%, demonstrating sufficient flexibility and breaking properties. However, although the content of the modified polyethylene resin (A-3) used on the surface side of this film was 60% by mass, which was within the specified content range, the content of the (meth)acrylic monomer in 100% by mass of the monomers constituting the modified polyethylene resin (A-3) was 9% by mass, which did not exceed 20% by mass. Therefore, in the test of the adhesion of the ink applied to the surface side of this film, the remaining ink was about one gradation or less, and it was recognized that the film had poor adhesion to ink. Therefore, it was confirmed that although this film has excellent handling properties and flexibility, it has poor adhesion to ink unless surface treatment such as corona treatment is performed.

[0064] [Comparative Example 5] As the thermoplastic resins for the front layer, middle layer and back layer, high density polyethylene, low density polyethylene, modified polyethylene resin (A-4) and modified polyethylene resin (B) were used in the amounts shown in Table 1 to prepare resin compositions for each layer. Using the above resin compositions for the surface layer, intermediate layer, and back layer, a film consisting of three types and three layers and having a total thickness of 80 μm was obtained by the manufacturing method using the above matte metal cooling roll and matte silicone rubber roll by nip molding. The film-forming conditions were adjusted so that the thickness of each layer was 4 μm for the surface layer, 64 μm for the intermediate layer, and 12 μm for the back layer, and this film was not subjected to surface treatment such as corona treatment. In addition, when the vicinity of the discharge outlet of the T-die was observed while the film was being collected, no adhesion of resin was found near the discharge outlet, and no abnormalities were observed in the appearance of the film, confirming that the film had a good appearance. The film consisting of the above surface layer, intermediate layer and back layer had a tensile modulus of 400 MPa and a tensile breaking elongation of 930%, confirming that it had sufficient flexibility and breaking properties. However, although the total content of the modified polyethylene resin (A-4) and modified polyethylene resin (B) used on the surface side of this film was 70% by mass, which was within the specified content range, the content of the (meth)acrylic monomer in 100% by mass of the monomers constituting the modified polyethylene resin (A-4) was 9% by mass, which did not exceed 20% by mass. Therefore, in the test of the adhesion of the ink applied to the surface side of this film, the remaining gradation was about one or less, and it was recognized that the film had poor adhesion to ink. Therefore, it was confirmed that although this film has excellent handling properties and flexibility, it has poor adhesion to ink unless surface treatment such as corona treatment is performed.

[0065] [Comparative Example 6] As the thermoplastic resins for the surface layer, intermediate layer and back layer, high density polyethylene, low density polyethylene and modified polyethylene resin (A-1) were used in the amounts shown in Table 1 to prepare resin compositions for each layer. When the above-mentioned resin compositions for the surface layer, middle layer and back layer were used to manufacture the films by nip molding using the matte metal cooling roll and matte silicone rubber roll described above, the film stuck noticeably to the metal cooling roll and wrapped around the roll, or was difficult to peel off, and it was not possible to obtain a film made from this resin composition. Therefore, it is presumed that film formation would be difficult if the surface layer were made only of the modified polyethylene resin (A).

[0066] [Table 1]

[0067] [Example 6] An acrylic adhesive (SK Dyne 1502C manufactured by Soken Chemical Industries, Ltd.) was applied onto the separator using the comma coat method so that the adhesive layer would be 25 μm thick after drying, and the adhesive layer was then dried for 5 minutes in a hot air dryer at 80°C to form an adhesive layer. The adhesive layer side of the prepared separator was bonded to the surface of the outer layer side of the film obtained in Example 1, thereby obtaining a laminated adhesive film in which the film of the present invention and the adhesive layer were sufficiently adhered to each other. This film has excellent handleability and flexibility, and it has been confirmed that it has good adhesion to adhesives even without surface treatment such as corona treatment. Therefore, it is presumed that an adhesive film has been obtained that can be suitably used in semiconductor manufacturing processes.

[0068] [Industrial Applicability] The present invention aims to provide a thermoplastic resin film using a specific modified polyethylene resin in a required content, which has sufficient adhesion with ink or adhesive, suppressing the influence of deterioration in adhesion over time, even when adhesion to ink or adhesive is required, and also has excellent handleability and flexibility. In addition, the present invention can be suitably used for decorative films, adhesive films, and adhesive films for semiconductor manufacturing processes by providing a printing layer or an adhesive layer on the thermoplastic resin film.

Claims

1. A thermoplastic film comprising at least two layers, The thermoplastic resin film is characterized in that at least one layer contains 35 to 90 mass % of at least one selected from the group consisting of the following modified polyethylene-based resin (A) and the following modified polyethylene-based resin (B), and 10 to 65 mass % of the other polyethylene-based resin (wherein the total mass of the at least one selected from the group consisting of the modified polyethylene-based resin (A) and the modified polyethylene-based resin (B) and the other polyethylene-based resin is taken as 100 mass %). Modified polyethylene resin (A) A modified polyethylene resin which is a copolymer obtained by polymerizing ethylene and a (meth)acrylic monomer, and contains more than 20% by mass of the (meth)acrylic monomer per 100% by mass of the monomers constituting the copolymer. Modified polyethylene resin (B) A modified polyethylene resin obtained by polymerizing ethylene, a (meth)acrylic monomer, and a copolymerizable acid anhydride monomer.

2. 2. The thermoplastic resin film according to claim 1, wherein the (meth)acrylic monomer used in the modified polyethylene resin (A) and the modified polyethylene resin (B) is at least one selected from the group consisting of (meth)acrylic acid and (meth)acrylic acid alkyl esters.

3. The thermoplastic resin film according to claim 1 or 2, wherein the (meth)acrylic monomer used in the modified polyethylene resin (A) and the modified polyethylene resin (B) is a (meth)acrylic acid alkyl ester having an alkyl group having 1 to 4 carbon atoms.

4. 3. The thermoplastic resin film according to claim 1, wherein the thermoplastic resin film has a tensile modulus in the range of 100 to 600 MPa.

5. A cosmetic film comprising the thermoplastic resin film according to claim 1 or 2, and a printed layer provided on the at least one layer.

6. 3. A pressure-sensitive adhesive film comprising the thermoplastic resin film according to claim 1 or 2, and a pressure-sensitive adhesive layer provided on the at least one layer.

7. The adhesive film for use in a semiconductor manufacturing process according to claim 6, which is used in a semiconductor manufacturing process.

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