Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K5/00—Use of organic ingredients
  • C08K5/16—Nitrogen-containing compounds
  • C08K5/20—Carboxylic acid amides
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B27/00—Layered products comprising a layer of synthetic resin
  • B32B27/32—Layered products comprising a layer of synthetic resin comprising polyolefins
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
  • C08J5/18—Manufacture of films or sheets
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K5/00—Use of organic ingredients
  • C08K5/04—Oxygen-containing compounds
  • C08K5/09—Carboxylic acids; Metal salts thereof; Anhydrides thereof
  • C08K5/098—Metal salts of carboxylic acids
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K5/00—Use of organic ingredients
  • C08K5/04—Oxygen-containing compounds
  • C08K5/13—Phenols; Phenolates
  • C08K5/134—Phenols containing ester groups
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L77/00—Compositions of polyamides obtained by reactions forming a carboxylic amide link in the main chain; Compositions of derivatives of such polymers
  • C08L77/02—Polyamides derived from omega-amino carboxylic acids or from lactams thereof
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K2201/00—Specific properties of additives
  • C08K2201/019—Specific properties of additives the composition being defined by the absence of a certain additive

Definitions

• the present invention relates to a polyamide resin composition, a film and a film laminate containing the same, and a pellet mixture.
• Packaging materials such as food packaging are often laminates made of different resins such as polyamide and polyolefin to impart functionality.
• resins such as polyamide and polyolefin
• compatibility of the different resins is poor, so the physical properties of the mixed resin after recycling are significantly reduced, and its applications are very limited.
• a compatibilizer Modified ethylene/ ⁇ -olefin copolymers are known as compatibilizers for polyamide and polyolefin.
• the polyamide resin composition needs to improve the material recyclability while maintaining the physical properties of the film obtained from the composition before recycling.
• the polyamide resin composition is required to have high transparency, tensile strength, puncture strength, pinhole resistance, and little film gel.
• flexibility and stretchability are also required, and it is known to use an aliphatic copolyamide to impart flexibility and stretchability to a polyamide film.
• Patent Document 1 discloses a multilayer structure of a polar layer containing nylon and a polyolefin layer, in which the polyolefin layer contains a compatibilizer component containing an anhydride and/or carboxylic acid functionalized ethylene/ ⁇ -olefin interpolymer having a specific melt viscosity and density, and indicates that waste of the multilayer structure can be recycled.
• Patent Document 2 discloses a laminate having a layered structure including a sealant layer and a reinforcing layer, in which the sealant layer contains a linear low-density polyethylene and a compatibilizer that is an unsaturated carboxylic acid-modified polyolefin, and the reinforcing layer contains a polyamide resin, thereby improving recyclability.
• Patent Document 3 discloses a polyamide resin composition containing 100 parts by mass of polyamide (A) and 3 to 30 parts by mass of acid-modified polyethylene (E) having a density of 0.915 to 0.975 g/ cm3 , and indicates that the composition has excellent heat aging resistance and is suitable for use in automobile parts.
• Patent Document 4 discloses a polyamide resin blend obtained by blending (A) a master batch obtained by melt-mixing (a) a polyamide resin and a modified ethylene- ⁇ -olefin copolymer in a ratio of 40/60 to 99/1 (weight ratio) with (B) a polyamide resin in a ratio of 1/99 to 60/40 (weight ratio), and discloses that a polyamide film molded from the blend has excellent pinhole resistance and transparency and has little generation of fisheyes.
• Patent Documents 3 and 4 only polyamide 6 is used as the polyamide resin.
• Patent Document 5 discloses a polyamide resin composition containing (A) a linear aliphatic nylon copolymer having a melting point of 130° C. or less and (B) a modified polyolefin resin in a predetermined ratio, and shows that a nylon laminate having excellent thermal adhesiveness can be obtained by coextrusion molding, which is a simple and inexpensive process.
• Patent Document 6 discloses a polyamide resin composition containing a polyamide resin (A) including an aliphatic homopolyamide and a copolymerized polyamide, and an impact-resistant material (B) such as a maleic anhydride-modified ethylene-butene copolymer in a predetermined ratio, and it is shown that the composition has excellent blow moldability while maintaining a good surface appearance of the molded article.
• Patent Document 7 discloses a material for hydrogen tank liners made of a polyamide resin composition containing (A) polyamide 6, (B) a copolymer polyamide, and (C) an impact-resistant material in a specified ratio, and shows that the material has excellent gas barrier properties and impact resistance at extremely low temperatures.
• Patent Document 8 discloses a polyamide resin composition containing a polyamide resin and a modified polyolefin resin in a specified ratio, and indicates that the composition has excellent heat resistance and is suitable for producing blow molded products.
• Patent Document 9 discloses a pelletizable thermoplastic polymer composition comprising (a) a polyamide and (b) a polymer polymerized from maleic anhydride and an olefin, and indicates that a product having improved durability can be obtained.
• Patent Document 10 discloses a masterbatch composition for use in preparing a polyamide blend from a polyamide, the masterbatch composition comprising an olefin-maleic anhydride copolymer and one or more carrier resins, and indicates that the masterbatch composition has good compatibility and does not cause phase separation, etc.
• Patent Documents 1 and 2 only disclose the inclusion of a compatibilizer in the polyolefin layer, but do not disclose the inclusion of a compatibilizer in the polyamide layer. In general, when a compatibilizer such as modified polyolefin is included in polyamide, problems such as the generation of film gels and reduced transparency arise.
• the polyamide resin compositions of Patent Documents 3 to 10 contain polyamide resin and modified polyolefin resin in a specified ratio, but these compositions are intended to improve properties such as heat aging resistance, transparency, moldability, impact resistance, and thermal adhesion, and do not take into consideration the recyclability of the waste of the resulting molded bodies, resulting in insufficient recyclability.
• the polyamide resin compositions of Patent Documents 3, 5, 7, and 8 are intended for use in automobile parts; laminates with nonwoven fabrics, woven fabrics, etc.; and it is difficult to apply them to packaging materials such as food packaging, where the generation of film gels and reduced transparency are problems.
• the film obtained from the polyamide resin blend of Patent Document 4 exhibits a certain level of pinhole resistance, transparency, reduced film gels, etc., but the levels are insufficient.
• the films obtained from the compositions of Patent Documents 6, 9, and 10 have insufficient physical properties such as film gels.
• the present invention aims to provide a polyamide resin composition that gives a film that is free from the deterioration of appearance caused by film gel and has excellent transparency, mechanical strength, and pinhole resistance, and that enables material recycling of a laminate of the film with a different type of resin film, as well as a film and a film laminate using the same.
• a further aim is to provide a pellet mixture that is suitably used in the production of the polyamide resin composition, film, and film laminate.
• the aliphatic copolyamide (A-2) is a copolymer selected from the group consisting of polyamide 6/66, polyamide 6/69, polyamide 6/11, polyamide 6/12, polyamide 6/66/11 and polyamide 6/66/12.
• the other component (C) contains a polyolefin (D) having no functional group, and the content of the (D) component relative to 100% by mass of the polyamide resin composition is 2 to 8% by mass.
• the other component (C) contains a compound (E) which is at least one selected from the group consisting of methylene bis-stearamide, ethylene bis-stearamide, butylene bis-stearamide, and hexamethylene bis-stearamide, and the content of the compound (E) relative to 100% by mass of the polyamide resin composition is 0.01 to 1% by mass.
• a polyamide film comprising the polyamide resin composition according to any one of [1] to [9].
• a laminate film comprising at least three layers, in the order of a layer containing the polyamide resin composition according to any one of [1] to [9], an adhesive layer, and a polyolefin layer.
• a laminate film comprising at least five layers, in which an adhesive layer and a polyolefin layer are laminated in this order on both sides of a layer containing the polyamide resin composition according to any one of [1] to [9].
• the laminate film according to [11] or [12], wherein the layer containing the polyamide resin composition is a biaxially stretched layer.
• a pellet mixture comprising: first pellets comprising a first aliphatic polyamide resin (a1) and a functional group-containing ethylene/C3-C8 ⁇ -olefin copolymer (B); and second pellets comprising a second aliphatic polyamide resin (a2);
• the first pellets (100 mass%) contain 60 to 90 mass% of a first aliphatic polyamide resin (a1), 10 to 40 mass% of the copolymer (B), and 0 to 9 mass% of other components (C), the aliphatic polyamide resin (a1) being an aliphatic homopolyamide;
• the second aliphatic polyamide resin (a2) contains 0 to 20 mass% of an aliphatic homopolyamide and 80 to 100 mass% of an aliphatic copolyamide, relative to 100 mass% of the aliphatic polyamide resin (a2); the content of the aliphatic homopolyamide is
• the present invention provides a polyamide resin composition that gives a film that is free from the deterioration of appearance caused by film gel and has excellent transparency, mechanical strength, and pinhole resistance, and that enables material recycling of a laminate of the film with a different type of resin film, as well as a film and a film laminate using the same. Furthermore, it is possible to provide a pellet mixture that is suitably used for producing the polyamide resin composition, film, and film laminate.
• the content of each component in a composition means the total amount of the multiple substances when the composition contains multiple substances corresponding to each component, unless otherwise specified.
• polyamide resin composition means a composition containing at least polyamide resin, and includes any form such as pellets, sheets, strands, chips, and molded products formed by various methods.
• pellets means one of the forms that a polyamide resin composition can take. The polyamide resin composition and pellets according to the present invention will be described in detail below.
• the polyamide resin composition of the present invention contains, relative to 100 mass% of the polyamide resin composition, 88 to 99 mass% of an aliphatic polyamide resin (A), 1 to 5 mass% of an ethylene/ ⁇ -olefin copolymer having 3 to 8 carbon atoms (B) having a functional group, and 0 to 9 mass% of other components (C); in the aliphatic polyamide resin (A), the ratio of the number of methylene groups to the number of amide groups is 3 or more and 11 or less; the aliphatic polyamide resin (A) is an aliphatic polyamide resin.
• the polyamide resin composition contains 1 to 50 mass% of an aliphatic homopolyamide (A-1) and 50 to 99 mass% of an aliphatic copolyamide (A-2) relative to 100 mass% of an amide resin (A); the DSC curve when the polyamide resin composition is heated from 0°C to 280°C at a rate of 20°C/min in an air atmosphere has a melting peak in the range of 150 to 205°C; and the number average molecular weight Mn of the polyamide resin composition measured by GPC is 50,000 to 60,000.
• the polyamide resin composition of the present invention By using the polyamide resin composition of the present invention, it is possible to obtain a film that is free from deterioration of appearance due to film gel and has excellent transparency, tensile strength, elongation, mechanical strength such as puncture strength, and pinhole resistance, and also enables material recycling of film waste.
• material recycling means reusing waste as a raw material for products. Specifically, it means that for a laminate film containing a layer containing a polyamide resin composition, particularly a laminate film containing at least a layer containing a polyamide resin composition and a layer containing a polyolefin, the waste is cut, crushed, or otherwise processed, melted and kneaded, and made into pellets or the like, and then reused as a raw material for new plastic products.
• the aliphatic polyamide resin (A) contains an aliphatic group in the constituent repeating unit and has an amide bond (-CONH-) in the main chain.
• the aliphatic polyamide resin (A) includes aliphatic homopolyamides and aliphatic copolymer polyamides, which may be used alone or in combination of two or more.
• the aliphatic homopolyamide (A-1) is a polyamide resin consisting of one type of structural unit derived from an aliphatic monomer.
• the aliphatic homopolyamide (A-1) may consist of at least one of one type of lactam and an aminocarboxylic acid which is a hydrolyzate of the lactam, or may consist of a combination of one type of diamine and one type of dicarboxylic acid.
• the combination of one type of diamine and one type of dicarboxylic acid is regarded as one type of monomer.
• lactams examples include ⁇ -caprolactam, enantholactam, undecane lactam, dodecane lactam ( ⁇ -laurolactam), ⁇ -pyrrolidone, and ⁇ -piperidone.
• the aminocarboxylic acid includes ⁇ -aminocaproic acid, 7-aminoheptanoic acid, 9-aminononanoic acid, 11-aminoundecanoic acid, and 12-aminododecanoic acid.
• Diamines include, for example, aliphatic diamines such as ethylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, undecamethylenediamine, dodecamethylenediamine, tridecanediamine, tetradecanediamine, pentadecanediamine, hexadecanediamine, heptadecanediamine, octadecanediamine, nonadecanediamine, eicosanediamine, 2-methyl-1,8-octanediamine, and 2,2,4/2,4,4-trimethylhexamethylenediamine.
• aliphatic diamines such as ethylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenedi
• Dicarboxylic acids include, for example, aliphatic dicarboxylic acids such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedionic acid, dodecanedionic acid, tridecanedionic acid, tetradecanedionic acid, pentadecanedioic acid, hexadecanedioic acid, octadecanedioic acid, and eicosanedioic acid.
• aliphatic dicarboxylic acids such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedionic acid, dodecanedionic acid, tridecanedionic acid, tetrade
• aliphatic homopolyamides include polyamide 4, polyamide 6, polyamide 7, polyamide 9, polyamide 10, polyamide 11, polyamide 12, polyamide 26, polyamide 44, polyamide 45, polyamide 46, polyamide 48, polyamide 49, polyamide 54, polyamide 55, polyamide 56, polyamide 66, polyamide 410, polyamide 412, polyamide 58, polyamide 59, polyamide 510, polyamide 512, polyamide 64, polyamide 65, polyamide 68, polyamide 69, polyamide 610, polyamide 611, polyamide 612, polyamide 96, polyamide 98, polyamide 99, polyamide 105, polyamide 616, polyamide 618, polyamide 910, polyamide 912, polyamide 106, polyamide 108, polyamide 109, polyamide 1010, polyamide 1012, polyamide 125, polyamide 126, polyamide 129, polyamide 1210, polyamide 1212, and polyamide 122.
• polyamide 6 or polyamide 66 are preferred, and polyamide 6 is particularly preferred, from the viewpoints of availability, economy, and the mechanical properties and heat resistance of the resulting molded body.
• the aliphatic copolyamide (A-2) is a polyamide resin composed of two or more kinds of constituent units derived from aliphatic monomers.
• the constituent units of the aliphatic copolyamide (A-2) are derived from a monomer selected from the group consisting of a combination of a diamine and a dicarboxylic acid, a lactam, and an aminocarboxylic acid.
• the combination of a diamine and a dicarboxylic acid is regarded as one type of monomer by combining one type of diamine and one type of dicarboxylic acid.
• Diamines include those listed as examples of raw materials for aliphatic homopolyamide (A-1).
• Dicarboxylic acids include those exemplified as raw materials for aliphatic homopolyamide (A-1).
• lactams include those exemplified as raw materials for the aliphatic homopolyamide (A-1).
• aminocarboxylic acids include those exemplified as raw materials for the aliphatic homopolyamide (A-1). These diamines, dicarboxylic acids, lactams and aminocarboxylic acids may be used alone or in combination of two or more.
• aliphatic copolyamide (A-2) include copolymers combining two or more of the monomers forming the polyamides exemplified as the aliphatic homopolyamide (A-1), and more specific examples include the aliphatic copolyamides polyamide 4/6, polyamide 6/66, polyamide 6/69, polyamide 6/610, polyamide 6/611, polyamide 6/612, polyamide 6/10, polyamide 6/11, polyamide 6/12, polyamide 6/66/11, polyamide 6/66/12, polyamide 6/66/610, polyamide 6/66/612, polyamide 6/610/12, and polyamide 6/612/12.
• These aliphatic copolyamides (A-2) can be used alone or as a mixture of two or more.
• the aliphatic copolyamide (A-2) is preferably selected from the group consisting of polyamide 6/66, polyamide 6/69, polyamide 6/11, polyamide 6/12, polyamide 6/66/11, polyamide 6/66/12, polyamide 6/610/12 and polyamide 6/612/12, more preferably selected from the group consisting of polyamide 6/66, polyamide 6/69, polyamide 6/11, polyamide 6/12, polyamide 6/66/11 and polyamide 6/66/12, even more preferably selected from the group consisting of polyamide 6/66, polyamide 6/12 and polyamide 6/66/12, with polyamide 6/66 being particularly preferred.
• the copolymerization ratio of polyamide 6 in these aliphatic copolyamides (A-2) is preferably 50% by mass or more, more preferably 70 to 95% by mass, and even more preferably 75 to 90% by mass.
• the production apparatus for the aliphatic polyamide resin (A) may be a known polyamide production apparatus, such as a batch reaction vessel, a single- or multi-vessel continuous reaction apparatus, a tubular continuous reaction apparatus, a kneading reaction extruder such as a single-screw kneading extruder or a twin-screw kneading extruder.
• the polymerization method may be a known method such as melt polymerization, solution polymerization, or solid-phase polymerization, and may be carried out by repeating normal pressure, reduced pressure, or pressurized operations. These polymerization methods may be used alone or in appropriate combination.
• the ratio [CH 2 ]/[NHCO] of the number of methylene groups ([CH 2 ] ) to the number of amide groups ([NHCO]) (hereinafter, the ratio of the number of methylene groups to the number of amide groups may be referred to as [CH 2 ]/[NHCO]) is 3 to 11.
• [CH 2 ]/[NHCO] is preferably 3 to 9, more preferably 4 to 8, and even more preferably 4 to 7.
• the ratio of the number of methylene groups to the number of amide groups [ CH Examples of aliphatic homopolyamides having a ratio of ]/[NHCO] of 3 to 11 include polyamide 4:3.0, polyamide 6:5.0, polyamide 7:6.0, polyamide 9:8.0, polyamide 10:9.0, polyamide 11:10.0, polyamide 12:11.0, polyamide 26:3.0, polyamide 44:3.0, polyamide 45:3.5, polyamide 46:4.0, polyamide 48:5.0, polyamide 49:5.5, polyamide 410:6.0, polyamide 412:7.0, polyamide 54:3.5, polyamide 55:4.0, polyamide 56:4.5, polyamide 58:5.5, polyamide 59:6.0, polyamide 510:6.5, polyamide 512:7.5, polyamide 64:4.0, and polyamide 65:4.
• aliphatic copolyamide having a ratio [CH 2 ] / [NHCO] of the number of methylene groups to the number of amide groups of 3 or more and 11 or less a copolymer using several kinds of raw material monomers forming the aliphatic homopolyamide can be mentioned. These can be used alone or in combination.
• the ratio of the number of methylene groups to the number of amide groups [CH 2 ]/[NHCO] can be determined by multiplying the ratio of the number of methylene groups to the number of amide groups in a homopolymer of the monomer constituting the repeating unit of the copolymer [CH 2 ]/[NHCO] by the molar fraction of that constituent repeating unit, and then adding up the values for all constituent repeating units.
• the ratio of the number of methylene groups to the number of amide groups [CH 2 ]/[NHCO] can be determined by multiplying the ratio of the number of methylene groups to the number of amide groups in each aliphatic polyamide resin [CH 2 ]/[NHCO] by the mixing ratio expressed as a molar ratio and adding up the values for all the aliphatic polyamide resins.
• the aliphatic polyamide resin (A) contains 1 to 50% by mass of the aliphatic homopolyamide (A-1) and 50 to 99% by mass of the aliphatic copolyamide (A-2) relative to 100% by mass of the aliphatic polyamide resin (A).
• the content of the aliphatic homopolyamide (A-1) is less than 1% by mass, the transparency of the film is deteriorated, and if it exceeds 50% by mass, the flexibility and stretchability are deteriorated. If the content of the aliphatic copolyamide (A-2) is less than 50% by mass, the flexibility and stretchability are deteriorated, and if it exceeds 99% by mass, the transparency and friction coefficient of the film are deteriorated.
• the content of the aliphatic homopolyamide (A-1) relative to 100% by mass of the aliphatic polyamide resin (A) is preferably 3 to 30% by mass, more preferably 4 to 20% by mass, and particularly preferably 5 to 15% by mass.
• the content of the aliphatic copolyamide (A-2) relative to 100% by mass of the aliphatic polyamide resin (A) is preferably 70 to 97% by mass, more preferably 80 to 96% by mass, and particularly preferably 85 to 95% by mass.
• the aliphatic homopolyamide (A-1) is preferably polyamide 6, and the aliphatic copolyamide (A-2) is preferably selected from the group consisting of polyamide 6/66, polyamide 6/69, polyamide 6/11, polyamide 6/12, polyamide 6/66/11 and polyamide 6/66/12.
• the aliphatic homopolyamide (A-1) is polyamide 6
• the aliphatic copolyamide (A-2) is polyamide 6/66 is particularly preferred.
• the relative viscosity of the aliphatic polyamide resin (A) is preferably 2.0 to 5.0, more preferably 2.0 to 4.5, and even more preferably 2.1 to 4.0. By setting the relative viscosity of the aliphatic polyamide resin (A) within the above range, it becomes easier to ensure the moldability of the film and the mechanical strength of the obtained film.
• the relative viscosity of aliphatic polyamide resin (A) is a value measured at 25°C by dissolving 1 g of polyamide resin (A) in 100 ml of 96% sulfuric acid in accordance with JIS K 6920.
• aliphatic polyamide resin (A) is a combination of two or more types, it is preferable to measure the relative viscosity by the above method, but if the relative viscosity of each polyamide resin and its mixing ratio are known, the average value calculated by multiplying each relative viscosity by the mixing ratio may be calculated as the relative viscosity of aliphatic polyamide resin (A).
• the melting point of the aliphatic polyamide resin (A) is preferably 150 to 205° C., more preferably 150 to 200° C., and further preferably 160 to 198° C.
• the melting point of the aliphatic polyamide resin (A) means the melting point of a mixture of the aliphatic homopolyamide (A-1) and the aliphatic copolyamide (A-2) constituting the polyamide resin composition. If the melting point of the aliphatic polyamide resin (A) is less than 150° C., the mechanical strength of the molded product is deteriorated. If the melting point of the aliphatic polyamide resin (A) is more than 205° C., the material recyclability is deteriorated.
• a laminated film including at least a layer including a polyamide resin composition and a layer including a polyolefin
• the melting point exceeds 205° C.
• excessive heating is required when the waste is melt-kneaded and processed into pellets, etc., which causes coloration, thermal degradation, etc. of the polyolefin contained in the waste.
• the melting point is the melting peak temperature in a DSC curve obtained by heating an aliphatic polyamide resin (A) to 280°C in an air atmosphere, holding the temperature at that temperature for 5 minutes, then lowering the temperature to 0°C at a rate of 20°C/min, and then heating the resin from 0°C to 280°C at a rate of 20°C/min.
• the terminal amino group concentration of the aliphatic polyamide resin (A) is preferably 2.0 to 5.5 ⁇ 10 eq/g, more preferably 2.5 to 5.0 ⁇ 10 eq/g, and even more preferably 2.8 to 4.8 ⁇ 10 eq/g.
• the terminal amino group concentration can be expressed as the equivalent of amino groups per 1 g of polymer, and can be measured by dissolving the polyamide resin in a phenol/methanol mixed solution and titrating with 1/50N hydrochloric acid.
• the terminal amino group concentration in the polyamide resin is preferably measured by the neutralization titration described above.
• the terminal amino group concentration of each polyamide resin component and its mixing ratio are known, the terminal amino group concentration of the polyamide resin may be determined by multiplying each terminal amino group concentration by the mixing ratio and adding up the total value.
• the number average molecular weight Mn of the aliphatic polyamide resin (A) measured by GPC is preferably 50,000 to 60,000, more preferably 53,000 to 60,000, and even more preferably 55,000 to 60,000. Furthermore, the ratio of weight average molecular weight Mw to number average molecular weight Mn: Mw/Mn of the aliphatic polyamide resin (A) measured by GPC is preferably 1.5 to 3.0, more preferably 1.5 to 2.8, and even more preferably 1.6 to 2.5.
• the Mn and Mw values are determined by gel permeation chromatography (GPC).
• the aliphatic polyamide resin (A) preferably has a melt flow rate (MFR) measured in accordance with ASTM D1238 at 230°C under a load of 2.16 kg of 1 to 100 g/10 min, more preferably 2 to 90 g/10 min, and even more preferably 3 to 80 g/10 min.
• MFR melt flow rate
• the content of the aliphatic polyamide resin (A) is 88 to 99% by mass in 100% by mass of the polyamide resin composition.
• the aliphatic polyamide resin (A) and the functional group-containing ethylene/ ⁇ -olefin copolymer (B) having 3 to 8 carbon atoms exhibit good compatibility, and the melt stability of the polyamide resin composition and the moldability of the film are improved.
• the deterioration of the appearance of the polyamide film formed from the polyamide resin composition due to film gel can be suppressed, and the transparency and good pinhole resistance of the film can be maintained.
• the material recyclability of the waste of the film is also improved.
• the content of the aliphatic polyamide resin (A) is preferably 89 to 98% by mass in 100% by mass of the polyamide resin composition.
• the polyamide resin composition contains a functional group-containing ethylene/ ⁇ -olefin copolymer (B) having 3 to 8 carbon atoms.
• the copolymer (B) has a functional group, and therefore functions as a compatibilizer between polyamide and polyolefin.
• the copolymer (B) may be one type or a combination of two or more types.
• the functional groups of the copolymer (B) include a carboxyl group (which may be in the form of a salt), an acid anhydride group, a carboxylic acid ester group, a carboxylic acid imide group, a carboxylic acid amide group, and an epoxy group. It is believed that at least a portion of these functional groups react with the amino groups of the aliphatic polyamide resin (A). Among these, from the viewpoint of compatibility between the polyamide and the polyolefin, it is preferable that the functional group be at least one selected from the group consisting of a carboxyl group, a carboxylic acid ester group, and an acid anhydride group, and an acid anhydride group is more preferable.
• Methods for introducing a functional group into an ethylene/C3-8 ⁇ -olefin copolymer include (i) copolymerizing a copolymerizable monomer having a functional group during polymerization of the copolymer, (ii) introducing a functional group into the molecular chain or molecular end of an ethylene/C3-8 ⁇ -olefin copolymer using a polymerization initiator, chain transfer agent, or the like, and (iii) grafting a compound having the functional group and a graftable functional group onto an ethylene/C3-8 ⁇ -olefin copolymer.
• These introduction methods can be used alone or in combination as appropriate.
• copolymer (B) is produced by method (ii) or (iii).
• copolymerizable monomers having these functional groups, and compounds having the functional groups and graftable functional groups include acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, crotonic acid, mesaconic acid, citraconic acid, glutaconic acid, cis-4-cyclohexene-1,2-dicarboxylic acid, endo-bicyclo-[2.2.1]-5-heptene-2,3-dicarboxylic acid, and metal salts of these carboxylic acids, monomethyl maleate, monomethyl itaconate, methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, hydroxyethyl acrylate, ethyl acrylate, ethyl acrylate, butyl acrylate, ethyl ...
• Suitable methacrylates include ethyl, methyl methacrylate, 2-ethylhexyl methacrylate, hydroxyethyl methacrylate, aminoethyl methacrylate, dimethyl maleate, dimethyl itaconate, maleic anhydride, itaconic anhydride, citraconic anhydride, endobicyclo-[2.2.1]-5-heptene-2,3-dicarboxylic anhydride, maleimide, N-ethylmaleimide, N-butylmaleimide, N-phenylmaleimide, acrylamide, methacrylamide, glycidyl acrylate, glycidyl methacrylate, glycidyl ethacrylate, glycidyl itaconate, and glycidyl citraconate.
• maleic anhydride, itaconic anhydride, or citraconic anhydride is preferred, maleic anhydride or itaconic anhydride is more preferred, and maleic anhydride is particularly preferred.
• the functional group concentration in copolymer (B) is preferably 1.0 to 60 ⁇ 10 ⁇ 5 eq/g, more preferably 2.0 to 40 ⁇ 10 ⁇ 5 eq/g, and even more preferably 3.0 to 30 ⁇ 10 ⁇ 5 eq/g.
• the functional group concentration of copolymer (B) can be expressed as the equivalent of a carboxyl group per 1 g of polymer, and is measured by neutralization titration with a 0.1 N KOH ethanol solution using a sample solution prepared using a solvent such as xylene and phenolphthalein as an indicator.
• the maleic anhydride modification rate (content (mass%) of groups derived from maleic anhydride) is preferably 0.1 mass% to 3 mass%, more preferably 0.3 mass% to 2 mass%, and particularly preferably 0.5 mass% to 1.5 mass%.
• Examples of a method for measuring the maleic anhydride modification rate include a method in which the equivalent of the carboxyl group obtained by the above neutralization titration is converted to a maleic acid modification rate, and a method in which the maleic anhydride modification rate is measured from a separately prepared calibration curve based on the peak intensity at a wave number of 1780 cm ⁇ 1 assigned to the carbonyl group in FT-IR.
• the copolymer (B) is an ethylene/ ⁇ -olefin copolymer having 3 to 8 carbon atoms. From the viewpoint of suppressing deterioration of the appearance of a film formed from the polyamide resin composition due to film gel and maintaining the transparency and good pinhole resistance of the film, it is preferable that the copolymer (B) does not contain a maleic anhydride monomer as a copolymerization component.
• the number of carbon atoms in the ⁇ -olefin is 3 to 8, preferably 4 to 6.
• Specific examples of ⁇ -olefins having 3 to 8 carbon atoms include 1-propene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 3-methyl-1-butene, 3-methyl-1-pentene, 3-ethyl-1-pentene, 4-methyl-1-pentene, 4-methyl-1-hexene, 4,4-dimethyl-1-hexene, 4,4-dimethyl-1-pentene, 4-ethyl-1-hexene, and 3-ethyl-1-hexene. These may be used alone or in combination of two or more.
• 1-propene, 1-butene, 1-hexene, and 1-octene are preferred, 1-propene, 1-butene, and 1-hexene are more preferred, and 1-hexene is particularly preferred.
• the proportion of ⁇ -olefin monomers having 3 to 8 carbon atoms in the total of 100 mol % of ethylene monomers and ⁇ -olefin monomers having 3 to 8 carbon atoms that constitute the copolymer is preferably 1 to 99 mol %, more preferably 5 to 95 mol %, and even more preferably 10 to 90 mol %.
• the molecular structure of the copolymer (B) may be linear or branched with long or short side chains.
• the copolymer (B) may be any of 1,4-pentadiene, 1,4-hexadiene, 1,5-hexadiene, 1,4-octadiene, 1,5-octadiene, 1,6-octadiene, 1,7-octadiene, 2-methyl-1,5-hexadiene, 6-methyl-1,5-heptadiene, 7-methyl-1,6-octadiene, 4-ethylidene-8-methyl-1,7-nonadiene, 4,8-dimethyl-1,4,8-decatriene (DMDT), dicyclopentadiene, Polyenes such as non-conjugated dienes and non-conjugated trienes, such as cyclohexadiene, cyclooctadiene, 5-vinylnorbornene, 5-ethylid
• copolymer (B) is preferably an ethylene/ ⁇ -olefin copolymer having 3 to 8 carbon atoms having a group derived from at least one selected from the group consisting of maleic anhydride and itaconic anhydride, more preferably an ethylene/propylene copolymer, ethylene/1-butene copolymer, ethylene/1-hexene copolymer, or ethylene/1-octene copolymer having a group derived from maleic anhydride, even more preferably an ethylene/propylene copolymer, ethylene/1-butene copolymer, or ethylene/1-hexene copolymer having a group derived from maleic anhydride, even more preferably an ethylene/1-butene copolymer, or ethylene/1-hexene copolymer having a group derived from maleic anhydride, and particularly preferably an ethylene/1-
• the melting point of copolymer (B) is preferably 70 to 120°C, more preferably 75 to 120°C, and even more preferably 80 to 115°C.
• the melting point is the melting peak temperature in the DSC curve when copolymer (B) is heated to 280°C in an air atmosphere, held at this temperature for 5 minutes, then cooled to 0°C at a rate of 20°C/min, and then heated from 0°C to 280°C at a rate of 20°C/min.
• the copolymer (B) preferably has a melt flow rate (MFR) measured in accordance with ASTM D1238 at 230°C under a load of 2.16 kg of 1 to 100 g/10 min, more preferably 3 to 90 g/10 min, and even more preferably 5 to 70 g/10 min.
• MFR melt flow rate
• the content of the copolymer (B) is 1 to 5% by mass in 100% by mass of the polyamide resin composition.
• the aliphatic polyamide resin (A) and the copolymer (B) show good compatibility, and the melt stability of the polyamide resin composition and the moldability of the film are improved.
• the deterioration of the appearance of the polyamide film formed from the polyamide resin composition due to film gel can be suppressed, the transparency of the film can be maintained, and the pinhole resistance in a low temperature environment can be improved.
• the content of the copolymer (B) is preferably 1.5 to 4.0% by mass, more preferably 2.0 to 3.0% by mass in 100% by mass of the polyamide resin composition. If the content of the copolymer (B) in 100% by mass of the polyamide resin composition is less than 1% by mass, the pinhole resistance and friction coefficient of the molded film in a low-temperature environment are not improved, and the material recyclability is deteriorated.
• the content exceeds 5% by mass, the dispersibility of the copolymer (B) in the polyamide resin composition is deteriorated, the transparency is reduced, the film gel is increased, and the appearance and material recyclability of the film are deteriorated.
• the polyamide resin composition may contain other components (C) other than the components (A) and (B).
• other components include polyamide resins other than the component (A), such as polyamide resins having an alicyclic or aromatic group in the main chain or side chain; thermoplastic resins other than the component (B); antioxidants, antiblocking agents, water repellents, lubricants, nucleating agents, plasticizers, foaming agents, stabilizers, ultraviolet absorbers, weather resistance agents, antifogging agents, colorants, etc.
• the polyamide resin composition contains a polyolefin (D) having no functional group, an antioxidant, a water repellent, and/or a lubricant.
• the content of the other component (C) is 0 to 9 mass%, preferably 0 to 5 mass%, and even more preferably 0 to 2 mass%, based on 100 mass% of the polyamide resin composition.
• the polyamide resin composition may contain a polyolefin (D) having no functional group.
• the polyolefin (D) does not have a functional group such as those exemplified in the copolymer (B).
• the polyolefin (D) may be one type or a combination of two or more types.
• polyolefin (D) examples include ethylene and ⁇ -olefins having 3 or more carbon atoms. Examples of ⁇ -olefins having 3 or more carbon atoms include those exemplified for copolymer (B).
• Polyolefin (D) may be a homopolymer or a copolymer of two or more olefins. As polyolefin (D), ethylene homopolymer or propylene homopolymer is preferred, and ethylene homopolymer is more preferred. Examples of ethylene homopolymer include high density polyethylene (HDPE), medium density polyethylene (MDPE), low density polyethylene (LDPE), linear low density polyethylene (LLDPE), etc. Among them, linear low density polyethylene is preferred in terms of transparency, mechanical strength, and flexibility.
• HDPE high density polyethylene
• MDPE medium density polyethylene
• LDPE low density polyethylene
• LLDPE linear low density polyethylene
• the polyolefin (D) preferably has a melt flow rate (MFR) measured in accordance with ASTM D1238 at 190°C under a load of 2.16 kg of 0.5 to 50 g/10 min, more preferably 1 to 40 g/10 min, and even more preferably 1 to 10 g/10 min.
• MFR melt flow rate
• the content of polyolefin (D) is 0 to 9 mass% of 100 mass% of the polyamide resin composition, preferably 2 to 8 mass%, and more preferably 2 to 5 mass%.
• the polyamide resin composition can have excellent mechanical strength, pinhole resistance, and material recyclability.
• the polyamide resin composition can obtain antiblocking properties suitable for a film even if it does not contain an antiblocking agent. From the viewpoints of economy and transparency, it is preferable that the polyamide resin composition does not substantially contain an antiblocking agent, and from the viewpoint of transparency, it is more preferable that the polyamide resin composition does not substantially contain silica.
• substantially free means that the content of the antiblocking agent or silica in 100% by mass of the polyamide resin composition is less than 0.01% by mass, preferably less than 0.005% by mass, and more preferably less than 0.001% by mass.
• the polyamide resin composition may contain an antiblocking agent.
• antiblocking agents include minerals such as diatomaceous earth, calcium carbonate, feldspars, and quartz, synthetic silica, and crosslinked resin beads.
• the antiblocking agent may be one type or a combination of two or more types.
• the polyamide resin composition preferably contains an antioxidant.
• the antioxidant include organic antioxidants such as phenolic compounds, phosphorus compounds, and sulfur compounds, and inorganic antioxidants such as metal halide compounds.
• the antioxidant may be one type or a combination of two or more types.
• the content of the antioxidant relative to 100% by mass of the polyamide resin composition is preferably 0.01 to 1% by mass, more preferably 0.02 to 0.8% by mass, and even more preferably 0.03 to 0.7% by mass.
• the polyamide resin composition preferably contains at least one compound (E) selected from the group consisting of methylene bis-stearic acid amide, ethylene bis-stearic acid amide, butylene bis-stearic acid amide, and hexamethylene bis-stearic acid amide.
• the compound (E) may be one type or a combination of two or more types.
• the laminated film including the layer containing the polyamide resin composition can be produced by a molding method such as air-cooled inflation molding or water-cooled inflation molding.
• the polyamide resin composition contains the compound (E), which can prevent the transparency of the laminated film from being reduced by water when the water-cooled inflation molding method is used, and can suppress the hydrolysis of the composition caused by water absorption during material recycling. Furthermore, the compound (E) also functions as a lubricant.
• the content of the compound (E) relative to 100% by mass of the polyamide resin composition is preferably 0.01 to 1% by mass, more preferably 0.02 to 0.8% by mass, and even more preferably 0.03 to 0.7% by mass.
• the polyamide resin composition preferably contains at least one compound (F) selected from the group consisting of terminal modified polyalkylene glycols, phosphates or phosphites, higher fatty acid monoesters, higher fatty acids, metal salts of higher fatty acids, higher fatty acid monoamides, N-substituted higher fatty acid monoamides, magnesium silicate, and substituted benzylidene sorbitols.
• higher fatty acids refer to fatty acids having 6 or more carbon atoms.
• Compound (F) may be one type or a combination of two or more types.
• the compound (F) functions as a lubricant.
• the lubrication between pellets before molding, between a processing machine and the pellets, or between molded films can be improved.
• a metal salt of a higher fatty acid is preferable, a metal salt of stearic acid is more preferable, and magnesium stearate or calcium stearate is even more preferable.
• the use of a metal salt of stearic acid is preferable because it has the effect of suppressing the generation of gel during material recycling.
• the content of the compound (F) relative to 100% by mass of the polyamide resin composition is preferably 0.01 to 1% by mass, more preferably 0.02 to 0.8% by mass, and even more preferably 0.03 to 0.7% by mass.
• the polyamide resin composition has a number average molecular weight Mn of 50,000 to 60,000 as measured by GPC.
• Mn number average molecular weight
• the number average molecular weight Mn is more preferably 53,000 to 60,000, and even more preferably 55,000 to 60,000.
• the ratio Mw/Mn of the weight average molecular weight Mw to the number average molecular weight Mn of the polyamide resin composition measured by GPC is preferably 1.5 to 3.0, more preferably 1.5 to 2.8, and even more preferably 1.6 to 2.5.
• the Mn and Mw values are determined by gel permeation chromatography (GPC).
• the polyamide resin composition is heated to 280°C in an air atmosphere, held at this temperature for 5 minutes, then cooled to 0°C at a rate of 20°C/min, and then heated from 0°C to 280°C at a rate of 20°C/min.
• the DSC curve has a melting peak in the range of 150 to 205°C. This melting peak is derived from the aliphatic polyamide resin (A). By having such a melting peak, material recyclability can be improved.
• a laminated film containing at least a layer containing a polyamide resin composition and a layer containing a polyolefin when waste of the film is material recycled, it is possible to suppress an increase in the melt kneading temperature when the waste is melt kneaded and processed into pellets, etc., and coloring and thermal deterioration due to excessive heating of the polyolefin contained in the waste can be prevented, and the performance of the obtained material recycled product can be improved.
• the melting peak temperature is more preferably 150 to 200°C, and more preferably 160 to 198°C.
• the melting peak in the DSC curve is less than 150°C, the mechanical strength of the molded product will deteriorate. If the melting peak in the DSC curve exceeds 205°C, material recyclability will deteriorate. Specifically, for a laminate film that includes at least a layer containing a polyamide resin composition and a layer containing a polyolefin, when waste from the film is to be material recycled, if the melting peak exceeds 205°C, excessive heating will be required when the waste is melt-kneaded and processed into pellets, etc., resulting in discoloration, thermal degradation, etc. of the polyolefin contained in the waste.
• the polyamide resin composition is preferably such that the DSC curve obtained by heating the composition to 280°C in an air atmosphere, holding the composition at this temperature for 5 minutes, then lowering the temperature to 0°C at a rate of 20°C/min, and then heating the composition from 0°C to 280°C at a rate of 20°C/min, further has a melting peak temperature in the range of 70 to 120°C.
• This melting peak is derived from the copolymer (B) and/or the polyolefin (D). By having such a melting peak, it is possible to improve the moldability and strength of the molded product.
• the melting peak temperature is preferably in the range of 74 to 120°C, and more preferably in the range of 78 to 113°C.
• the method for producing the polyamide resin composition is not particularly limited.
• the following Production Methods 1 and 2 can be applied as the method for producing the polyamide resin composition.
• the polyamide resin composition is obtained by melt-kneading the aliphatic polyamide resin (A) and the copolymer (B) in a kneader.
• the polyamide resin composition may contain other components (C).
• the kneader include single-screw and twin-screw extruders, Banbury mixers, kneaders, mixing rolls, and the like.
• any method may be used, such as a method of blending all raw materials using a twin-screw extruder and then melt-kneading, or a method of blending some raw materials and then using a side feeder to mix the remaining raw materials during melt-kneading.
• the polyamide resin composition is melted in a film forming machine or the like and processed into a film, it is preferable to process it into a pellet shape in advance from the viewpoint of film production stability and dispersibility of each component in the polyamide resin composition.
• the first aliphatic polyamide resin (a1) and the copolymer (B) are melt-kneaded in advance in a kneader to obtain a melt-kneaded product (G).
• a second aliphatic polyamide resin (a2) is separately prepared.
• the melt-kneaded product (G) and the first and second aliphatic polyamide resins may each contain another component (C).
• the melt-kneaded product (G) and the second aliphatic polyamide resin (a2) may be molded into pellets, and then these pellets and other components (C) as necessary may be uniformly dry-blended to a specific ratio using, for example, a tumbler, a mixer, etc. to obtain a pellet mixture.
• the pellet mixture may also be melt-kneaded in a kneader to obtain a polyamide resin composition.
• a kneader the one exemplified in the production method 1 may be used.
• the copolymer (B) is melt-kneaded in advance with the first aliphatic polyamide resin (a1) to produce a melt-kneaded product (G), which is then processed into pellets, and then the pellets are dry-blended with the pellets of the second aliphatic polyamide resin (a2).
• the first pellet containing the melt-kneaded product (G) may contain the polyolefin D.
• a third pellet containing polyolefin (D) may be prepared separately from the first pellet containing the melt-kneaded product (G) and the second pellet containing the second aliphatic polyamide resin (a2), and these pellets may be uniformly dry-blended in a specific ratio to obtain a pellet mixture.
• the pellet mixture may also be melt-kneaded in a kneader to obtain a polyamide resin composition. The methods of dry blending and melt-kneading are as described above.
• pellet mixture When producing a polyamide resin composition by the above-mentioned production method 2, it is preferable to use a pellet mixture containing a first pellet containing a first aliphatic polyamide resin (a1) and a functional group-containing ethylene/ ⁇ -olefin copolymer (B) having 3 to 8 carbon atoms (hereinafter also referred to as copolymer (B)); and a second pellet containing a second aliphatic polyamide resin (a2). Note that the second pellet is not the first pellet. That is, the polyamide resin compositions constituting the first pellet and the second pellet are different from each other.
• the second pellet may contain less than 1.0 mass% of copolymer (B) in 100 mass% of the second pellet, but it is preferable that it does not contain copolymer (B).
• the first pellet and the second pellet may each be a combination of one type or two or more types.
• the first pellets and the second pellets may each contain other components (C) such as a polyolefin (D) having no functional group, an antioxidant, a compound (E), a compound (F), etc. It is preferable that the second pellets do not contain a polyolefin (D) having no functional group.
• the pellet mixture may contain, in addition to the first and second pellets, other components (C) such as a polyolefin (D) having no functional groups, an antioxidant, a compound (E), a compound (F), etc.
• the polyolefin (D) having no functional groups is preferably contained in the pellet mixture as the third pellets.
• the ratio of the number of methylene groups to the number of amide groups is 3 or more and 11 or less.
• the aliphatic polyamide resin (a1) and the aliphatic polyamide resin (a2) can be the polyamide resins exemplified in the aliphatic polyamide resin (A).
• the aliphatic polyamide resin (a1) and the aliphatic polyamide resin (a2) may be the same or different, but are preferably different.
• the aliphatic polyamide resin (a1) and the aliphatic polyamide resin (a2) may each be one type or a combination of two or more types.
• the content of the first aliphatic polyamide resin (a1) is preferably 60 to 90 mass% in 100 mass% of the first pellets. From the viewpoint of reducing film gel, the content of the first aliphatic polyamide resin (a1) is more preferably 65 mass% or more, and even more preferably 68 mass% or more in 100 mass% of the first pellets. Furthermore, from the viewpoint of improving mechanical properties, the content of the first aliphatic polyamide resin (a1) is more preferably 88 mass% or less, and even more preferably 85 mass% or less in 100 mass% of the first pellets.
• the aliphatic polyamide resin (a1) is preferably an aliphatic homopolyamide, more preferably polyamide 6 or polyamide 66, and particularly preferably polyamide 6.
• the copolymer (B) is as described above, including the preferred embodiments.
• the melting point of the copolymer (B) is preferably 70 to 120°C, more preferably 75 to 120°C, and even more preferably 80 to 115°C.
• the melting point is the melting peak temperature in the DSC curve when the copolymer (B) is heated to 280°C in an air atmosphere, held at this temperature for 5 minutes, then cooled to 0°C at a cooling rate of 20°C/min, and then heated from 0°C to 280°C at a rate of 20°C/min.
• the content of copolymer (B) is preferably 10 to 40 mass% in 100 mass% of the first pellets. From the viewpoint of pinhole resistance and material recyclability of film waste, the content of copolymer (B) is more preferably 12 mass% or more, and even more preferably 15 mass% or more. Furthermore, from the viewpoint of film transparency and film gel, the content of copolymer (B) is more preferably 35 mass% or less, and even more preferably 32 mass% or less in 100 mass% of the first pellets.
• the content of the other component (C) is preferably 0 to 9 mass% in 100 mass% of the first pellet.
• the content of the other component (C) is more preferably 3 mass% or less, and even more preferably 1 mass% or less.
• the content of the other component (C) is more preferably 0.1 mass% or more, and even more preferably 0.2 mass% or more in 100 mass% of the first pellet.
• the first pellet preferably contains an antioxidant, a compound (E) and/or a compound (F) as the other component (C).
• the MFR of the first pellets measured in accordance with ASTM D1238 at 230°C under a load of 2.16 kg is preferably 1 to 40 g/10 min.
• the MFR of the first pellets is more preferably 2 g/10 min or more, even more preferably 3 g/10 min or more, and particularly preferably 4 g/10 min or more.
• the MFR of the first pellets is more preferably 35 g/10 min or less, and even more preferably 30 g/10 min or less.
• the content of the first pellets is preferably 2% by mass or more, more preferably 4% by mass or more, and even more preferably 6% by mass or more, based on 100% by mass of the pellet mixture. Also, from the viewpoint of the dispersibility of each component in the polyamide resin composition, the content of the first pellets is preferably 25% by mass or less, more preferably 20% by mass or less, even more preferably 15% by mass or less, even more preferably 12% by mass or less, and particularly preferably 11.5% by mass or less, based on 100% by mass of the pellet mixture.
• the second pellets contain a second aliphatic polyamide resin (a2).
• the content of the second aliphatic polyamide resin (a2) is preferably 95 to 100 mass%, more preferably 97 to 100 mass%, and even more preferably 99 to 100 mass%, based on 100 mass% of the second pellets.
• the second pellets may contain less than 1.0% by mass of copolymer (B) based on 100% by mass of the second pellets. In a preferred embodiment, the second pellets do not contain copolymer (B).
• the second aliphatic polyamide resin (a2) preferably contains 0 to 20 mass% of an aliphatic homopolyamide and 80 to 100 mass% of an aliphatic copolyamide, relative to 100 mass% of the aliphatic polyamide resin (a2). It is more preferable that the aliphatic polyamide resin (a2) contains only an aliphatic copolyamide.
• the aliphatic copolyamide is preferably selected from the group consisting of polyamide 6/66, polyamide 6/69, polyamide 6/11, polyamide 6/12, polyamide 6/66/11 and polyamide 6/66/12, and is particularly preferably polyamide 6/66.
• the content of the other component (C) is preferably 5% by mass or less, more preferably 0 to 3% by mass, and even more preferably 0 to 1% by mass, based on 100% by mass of the second pellet.
• the second pellet preferably contains an antioxidant, a compound (E) and/or a compound (F) as the other component (C).
• the second aliphatic polyamide resin (a2) preferably has a relative viscosity of 2.5 to 5.0, measured at 25°C by dissolving 1 g of polyamide resin in 100 ml of 96% sulfuric acid in accordance with JIS K 6920.
• the relative viscosity of the second aliphatic polyamide resin (a2) is more preferably 2.8 or more, and even more preferably 2.9 or more.
• the relative viscosity of the second aliphatic polyamide resin (a2) is more preferably 4.5 or less, and even more preferably 4.1 or less.
• the second aliphatic polyamide resin (a2) is a combination of two or more types, it is preferable to measure the relative viscosity by the above method, but when the relative viscosity of each polyamide resin and its mixing ratio are known, the relative viscosity of the second aliphatic polyamide resin (a2) may be determined by adding up the values obtained by multiplying each relative viscosity by the mixing ratio.
• the melting point of the second aliphatic polyamide resin (a2) is preferably 150 to 205°C, and more preferably 150 to 200°C.
• the melting point is the melting peak temperature in the DSC curve when the second aliphatic polyamide resin (a2) is heated to 280°C in an air atmosphere, held at this temperature for 5 minutes, then cooled to 0°C at a cooling rate of 20°C/min, and then heated from 0°C to 280°C at a rate of 20°C/min.
• the MFR of the second aliphatic polyamide resin (a2) measured in accordance with ASTM D1238 at 230°C under a load of 2.16 kg, is preferably 1 to 20 g/10 min, more preferably 1 to 18 g/10 min, and even more preferably 2 to 15 g/10 min.
• the content of the second pellets is preferably 66% by mass or more, more preferably 72% by mass or more, even more preferably 80% by mass or more, and particularly preferably 83.5% by mass or more, based on 100% by mass of the pellet mixture.
• the content of the second pellets is preferably 98% by mass or less, more preferably 96% by mass or less, and even more preferably 94% by mass or less, based on 100% by mass of the pellet mixture.
• the content of the aliphatic homopolyamide is 1 to 50 mass%, and the content of the aliphatic copolyamide is 50 to 99 mass%, relative to 100 mass% in total of the first aliphatic polyamide resin (a1) and the second aliphatic polyamide resin (a2).
• the content of the aliphatic homopolyamide relative to 100% by mass of the total of the aliphatic polyamide resin (a1) and the aliphatic polyamide resin (a2) is preferably 3 to 30% by mass, more preferably 4 to 20% by mass, and particularly preferably 5 to 15% by mass.
• the content of the aliphatic copolyamide relative to 100% by mass of the total of the aliphatic polyamide resin (a1) and the aliphatic polyamide resin (a2) is preferably 70 to 97% by mass, more preferably 80 to 96% by mass, and particularly preferably 85 to 95% by mass.
• the pellet mixture may contain a third pellet containing the polyolefin (D) in addition to the first pellet and the second pellet. In this case, it is preferable that the first pellet and the second pellet do not contain the polyolefin (D).
• the third pellet may be one type or a combination of two or more types.
• the content of the polyolefin (D) is preferably 95 to 100 mass%, more preferably 97 to 100 mass%, and even more preferably 99 to 100 mass%, based on 100 mass% of the third pellets.
• the third pellets may contain an antioxidant, a compound (E) and/or a compound (F) as other components (C).
• the content of the third pellets is preferably 0 to 9 mass% of 100 mass% of the pellet mixture, more preferably 2 to 8 mass%, and even more preferably 2 to 5 mass%.
• the content of the third pellets can be 0 mass% or more of 100 mass% of the pellet mixture, and more preferably 2 mass% or more.
• the content of the third pellets is preferably 9 mass% or less of 100 mass% of the pellet mixture, more preferably 8 mass% or less, and even more preferably 5 mass% or less.
• the total content of the first aliphatic polyamide resin (a1) and the second aliphatic polyamide resin (a2) is preferably 88 to 99% by mass, more preferably 89 to 98% by mass, based on 100% by mass of the kneaded product after melt kneading the pellet mixture.
• the aliphatic polyamide resin (A) and the copolymer (B) exhibit good compatibility, and the melt stability and film moldability of the polyamide resin composition are improved.
• the deterioration of the appearance of the polyamide film formed from the polyamide resin composition due to film gel can be suppressed, and the transparency and good pinhole resistance of the film can be maintained.
• the material recyclability of the waste film is also improved.
• the content of copolymer (B) is preferably 1 to 5 mass%, more preferably 1.5 to 4.0 mass%, and even more preferably 2.0 to 3.0 mass% in 100 mass% of the kneaded product after melt kneading the pellet mixture.
• the aliphatic polyamide resin (A) and copolymer (B) exhibit good compatibility, and the melt stability of the polyamide resin composition and the moldability of the film are improved. Furthermore, it is possible to suppress deterioration of the appearance of a polyamide film formed from the polyamide resin composition due to film gel, maintain the transparency of the film, and improve pinhole resistance in a low-temperature environment.
• a laminate film containing at least a layer containing a polyamide resin composition and a layer containing a polyolefin when waste of the film is material recycled, the compatibility of both layers is improved, and the homogeneity of the recycled plastic raw material is improved.
• the content of the other component (C) is preferably 0 to 9 mass%, more preferably 0 to 5 mass%, and even more preferably 0 to 2 mass%, based on 100 mass% of the kneaded product after melt kneading the pellet mixture.
• the content of polyolefin (D) is preferably 2 to 8 mass%, and more preferably 2 to 5 mass%, based on 100 mass% of the kneaded product after melt kneading the pellet mixture.
• the kneaded product obtained by melt-kneading the pellet mixture has a number average molecular weight Mn measured by GPC of preferably 50,000 to 60,000, more preferably 53,000 to 60,000, and even more preferably 55,000 to 60,000. Furthermore, the ratio of weight average molecular weight Mw to number average molecular weight Mn: Mw/Mn, measured by GPC, of the kneaded product obtained by melt-kneading the pellet mixture is preferably 1.5 to 3.0, more preferably 1.5 to 2.8, and even more preferably 1.6 to 2.5.
• the Mn and Mw values are determined by gel permeation chromatography (GPC).
• the pellet mixture can be melt-kneaded to obtain a polyamide resin composition.
• the preferred range of the melting peak temperature of the polyamide resin composition thus obtained is as described above.
• Another aspect of the present invention is the first pellet for use in admixture with the second pellet in the manufacture of a pellet mixture.
• Yet another aspect of the present invention is the second pellet for use in admixture with the first pellet in the manufacture of a pellet mixture.
• the pellets can be obtained, for example, by extruding the polyamide resin composition in the form of strands from an extruder or the like, and cutting the strands with a cutter having a rotary blade.
• Pellets may have a spherical, rectangular, spheroidal, slightly deformed from an exact spheroid, a cylindrical shape with a circular or elliptical cross section, etc.
• the pellets are preferably spherical, spheroidal, or cylindrical with a circular or elliptical cross section.
• the pellet has an elliptical cross section
• its major axis is preferably 1 to 5 mm, more preferably 2 to 4 mm, and even more preferably 2.0 to 3.5 mm.
• its minor axis is preferably 1 to 3 mm, and even more preferably 2 to 3 mm.
• the ratio of major axis to minor axis is not particularly limited, but is preferably 1 to 4.
• the long and short diameters of the pellets can be controlled, for example, by adjusting the nozzle diameter of the extruder, etc., and changing the diameter of the strands.
• the length of the pellet is not particularly limited, but is preferably 2 to 4 mm, and more preferably 2.5 to 4.0 mm or less.
• the polyamide film contains a polyamide resin composition.
• the polyamide film may be an unstretched polyamide film, or may be a stretched polyamide film obtained by stretching the unstretched polyamide film. From the viewpoint of mechanical strength, the polyamide film is preferably a stretched polyamide film.
• the method for producing the polyamide film is not particularly limited, and for example, a known production method can be applied.
• the polyamide resin composition obtained by the above-mentioned production method 1 is melt-kneaded using an extruder, extruded into a film using a die such as a T-die or a coat hanger die, cast on a casting roll surface, and then cooled to produce a polyamide film.
• a polyamide film can be produced in a similar manner by melt-kneading the melt-kneaded product (G) or the first pellets, the aliphatic polyamide resin (a2) or the second pellets, and any other components using an extruder according to the above-mentioned production method 2.
• a polyamide film can be produced in a similar manner by melt-kneading the pellet mixture using an extruder or the like.
• the produced polyamide film may be stretched to form a stretched film.
• the produced polyamide film may be uniaxially stretched to form a uniaxially stretched film, or biaxially stretched (simultaneous biaxial stretching or sequential biaxial stretching) to form a biaxially stretched film.
• the stretching method is not particularly limited, and examples thereof include uniaxial stretching using a heated roll, simultaneous biaxial stretching using a tubular method, and sequential biaxial stretching using a heated roll and a tenter.
• the temperature of the heated roll is not particularly limited, and can be in the range of 35°C to 130°C, and can be appropriately selected depending on the material of the polyamide film and the intended stretching ratio.
• the stretching ratio includes the stretching ratio in the extrusion direction (MD) of the film and the perpendicular direction (TD) to the extrusion direction of the film.
• the stretching ratio in the extrusion direction of the film is not particularly limited, and is preferably 2 times or more, more preferably 2 to 6 times, and particularly preferably 2.5 to 5 times.
• the stretching ratio in the perpendicular direction to the extrusion direction of the film is not particularly limited, and is preferably 2 times or more, more preferably 2 to 6 times, and particularly preferably 2.5 to 5 times.
• the stretching ratio can be adjusted depending on the purpose.
• the thickness of the film is not particularly limited and may be appropriately selected depending on the purpose, etc.
• the thickness of the film can be, for example, 10 ⁇ m to 300 ⁇ m in the case of an unstretched film, and 5 ⁇ m to 100 ⁇ m in the case of a stretched film.
• Polyamide films exhibit excellent pinhole resistance.
• the pinhole resistance can be evaluated by performing a 1000-time bending test at 5°C on an unstretched polyamide film using a Gelbo Flex Tester (manufactured by Tester Sangyo Co., Ltd.) in accordance with MIL-B-131C, placing the film on a recording paper, applying India ink, and counting the number of black dots recorded on the recording paper.
• the number of black dots counted is preferably 110 or less per 0.03 m2 , more preferably 80 or less per 0.03 m2 , and even more preferably 70 or less per 0.03 m2 .
• the haze ratio of the polyamide film is preferably 25% or less, more preferably 15% or less, and even more preferably 10% or less.
• the haze ratio of the polyamide film is measured in accordance with ASTM D-1003.
• the gloss value of the polyamide film is preferably 50% or more, more preferably 80% or more, and even more preferably 100% or more.
• the gloss value of the polyamide film is measured in accordance with ASTM D-523.
• the laminated film includes at least one layer (also referred to as a polyamide film layer) containing a polyamide resin composition.
• the manufacturing method of the laminated film includes a method including a step of laminating an additional layer on one or both sides of the polyamide film.
• the lamination method is not particularly limited, and includes the co-extrusion method, extrusion lamination method, dry lamination method, etc. described in JP-A-2011-225870, and the co-extrusion method is preferable from the viewpoint of economic efficiency.
• the manufactured laminated film may be stretched to form a stretched laminated film.
• the manufactured laminated film may be uniaxially stretched to form a uniaxially stretched film laminate, or biaxially stretched (simultaneous biaxial stretching or sequential biaxial stretching) to form a biaxially stretched film laminate.
• the stretching method and stretching ratio are as described in the section on polyamide film.
• the laminated film can be produced by a molding method such as air-cooled inflation molding or water-cooled inflation molding.
• the air-cooled inflation molding requires simple equipment and has good workability because the width of the film can be easily changed simply by adjusting the blow ratio, and therefore the film can be produced with good productivity.
• the molding temperature is preferably from the melting point of the raw resin used to less than 300°C.
• the molding temperature can be, for example, 230°C to 260°C.
• the blow-up ratio refers to the ratio of the maximum bubble diameter to the die diameter, and is preferably 1.1 to 3.0, and more preferably 1.2 to 2.5.
• the take-up speed is determined by the thickness, width, and extrusion amount of the film, and can be adjusted within a range that maintains film formation stability, but is generally preferably 1 to 150 m/min, and more preferably 5 to 100 m/min.
• the additional layer is not particularly limited as long as the laminated film exhibits the effect of the polyamide film, and may be, for example, a polyolefin layer and an adhesive layer.
• the adhesive layer is appropriately selected for the purpose of improving the adhesion and moldability between the polyamide film layer and the polyolefin layer according to the present invention.
• the polyamide film layer according to the present invention is not a polyolefin layer or an adhesive layer.
• the polyolefin layer and the adhesive layer may contain additives.
• the additives may be any of those exemplified as other components (C).
• Polyolefins constituting the polyolefin layer include non-polar polyolefins such as low-density polyethylene, linear low-density polyethylene, high-density polyethylene, ethylene/ ⁇ -olefin copolymers with 3 or more carbon atoms, propylene homopolymers, propylene/ ⁇ -olefin copolymers with 4 or more carbon atoms, ethylene/acrylic acid copolymers, ethylene/vinyl acetate copolymers, ethylene/acrylic acid ester copolymers, and ethylene/methacrylic acid copolymers.
• non-polar polyolefins such as low-density polyethylene, linear low-density polyethylene, high-density polyethylene, ethylene/ ⁇ -olefin copolymers with 3 or more carbon atoms, propylene homopolymers, propylene/ ⁇ -olefin copolymers with 4 or more carbon atoms, ethylene/acrylic acid
• non-polar polyolefins and ethylene/vinyl acetate copolymers are preferred, and linear low-density polyethylene is more preferred.
• the polyolefin layer is a layer of non-polar polyolefin, the water vapor barrier properties of the laminated film tend to be improved.
• the polyolefin layer is a layer of ethylene/vinyl acetate copolymer, the oxygen gas permeability of the laminated film tends to be reduced.
• a laminated film containing at least a polyamide film layer and a polyolefin layer is not only suitable for use in food packaging, but also has excellent material recyclability for the waste film.
• the adhesive layer is composed of an adhesive resin or adhesive.
• adhesive resins include acid-modified polyolefin resins such as acid-modified polyethylene grafted with at least one monomer selected from unsaturated carboxylic acids and their derivatives, such as maleic acid-modified polyethylene, ionomers, ethylene/acrylic acid copolymers, ethylene/methacrylic acid copolymers, etc.
• adhesives include solvent-based adhesives and solventless adhesives, and some are used for adhesion with one liquid as well as those that are used by mixing two liquids.
• adhesives include epoxy-based adhesives and urethane-based adhesives, with urethane-based adhesives being preferred.
• urethane-based adhesives include aromatic ether-based, aliphatic ester-based, and aromatic ester-based adhesives.
• the layer structure of the laminated film include two layers of a polyamide film layer and a polyolefin layer, three layers of a polyamide film layer/adhesive layer/polyolefin layer, at least three layers of a polyamide film layer and a polyolefin layer, and at least one additional layer selected from the group consisting of a polyamide film layer, an adhesive layer, and a polyolefin layer, and at least four layers of a polyamide film layer, a polyolefin layer, and an adhesive layer, and at least one additional layer selected from the group consisting of a polyamide film layer, an adhesive layer, and a polyolefin layer.
• a laminated film containing at least three layers in which a layer containing a polyamide resin composition, an adhesive layer, and a polyolefin layer are laminated in this order, or a laminated film containing at least five layers in which an adhesive layer and a polyolefin layer are laminated in this order on both sides of a layer containing a polyamide resin composition, respectively, is preferred.
• the laminated film is an unstretched laminated film and a deep drawing packaging film, it is preferred that the laminated film has a polyolefin layer as an inner layer.
• the layer in contact with the outside air is the outer layer, and the layer in contact with the food to be packaged is the inner layer.
• the layer containing the polyamide resin composition may be a biaxially stretched layer.
• the thickness of the laminated film is not particularly limited and can be selected depending on the application.
• the thickness of each layer of the polyamide film in the laminated film can be 1 to 300 ⁇ m, preferably 2 to 100 ⁇ m, and more preferably 5 to 80 ⁇ m.
• the thickness of each layer of the polyolefin layer can be appropriately selected depending on the purpose, and is preferably in the range of, for example, 8 to 120 ⁇ m.
• the thickness of each layer of the adhesive layer can be selected depending on the purpose, and is preferably in the range of, for example, 1 to 100 ⁇ m.
• the total thickness of the laminated film is not particularly limited and is preferably 5 to 500 ⁇ m, more preferably 20 to 300 ⁇ m, and particularly preferably 50 to 200 ⁇ m.
• the polyamide resin composition and the pellet mixture can be used as raw materials for various molded products.
• the molded products containing the polyamide resin composition can be used for a wide range of applications, such as packaging films for food packaging, automobile parts, computers and related devices, optical device parts, electric and electronic devices, information and communication devices, precision devices, civil engineering and construction supplies, medical supplies, and household goods, and are suitable for packaging films, and are particularly useful for food packaging films.
• Polyamide films and laminated films do not suffer from the deterioration of appearance caused by film gel, and have excellent pinhole resistance in low-temperature environments. For this reason, polyamide films and laminated films are suitable for use in packaging goods, particularly food packaging.
• Unstretched polyamide film and unstretched laminate film have excellent deep drawability and can therefore be suitably used as food packaging films, particularly as deep draw packaging films for food.
• unstretched polyamide film is used as a deep draw packaging film
• food is placed in the deep draw packaging base material obtained by deep draw molding the film, and packaged using a lid material.
• foods that can be placed in the deep draw packaging base material include sliced foods such as ham and cheese.
• the lid material is not particularly limited and can be selected appropriately depending on the purpose.
• Stretched polyamide film and stretched laminate film have excellent mechanical strength and oxygen barrier properties, making them useful as food packaging films for filling and packaging semi-liquid foods such as sausages (paste products) and solid foods such as processed meats and hams.
• laminate films containing at least a layer containing a polyamide resin composition and a polyolefin layer and laminate films in which a layer containing a polyamide resin composition, an adhesive layer and a polyolefin layer are laminated in this order, are not only suitable for use in food packaging, but are also useful because of their excellent material recyclability for the film waste.
• DSC Measurement Each Raw Material Each raw material was measured by a differential scanning calorimeter (DSC). The sample was heated to 280°C at a rate of 20°C/min in an air atmosphere, and held at this temperature for 5 minutes. Thereafter, the temperature was lowered to 0°C at a rate of 20°C/min, and then the temperature was raised from 0°C to 280°C at a rate of 20°C/min. The top temperature of the endothermic peak during the second heating was taken as the melting peak temperature (melting point). (2) Polyamide resin composition The polyamide resin composition was measured by a differential scanning calorimeter (DSC).
• DSC differential scanning calorimeter
• the sample was heated to 280°C at a rate of 20°C/min in an air atmosphere, held at this temperature for 5 minutes, and then cooled to 0°C at a rate of 20°C/min.
• the top temperature of the exothermic peak was taken as the crystallization temperature.
• the sample was then heated from 0°C to 280°C at a rate of 20°C/min.
• the top temperature of the endothermic peak during the second heating was taken as the melting peak temperature (melting point).
• MFR 230°C and load 2.16 kg
• the MFR of the aliphatic polyamide resin (A) and the acid-modified ethylene/ ⁇ -olefin copolymer (B) was measured at 230° C. and a load of 2.16 kg in accordance with ASTM D 1238.
• the MFR of the polyolefin having no functional group (D) was measured at 190° C. and a load of 2.16 kg in accordance with ASTM D 1238.
• Terminal amino group concentration For aliphatic polyamide resin (A), a predetermined amount of polyamide resin was placed in a stopcocked Erlenmeyer flask, and 40 mL of a previously prepared solvent: phenol/methanol (volume ratio 7/3) was added. The resin was stirred with a magnetic stirrer to dissolve, and titrated with 1/50 N hydrochloric acid using thymol blue as an indicator to determine the terminal amino group concentration (eq/g).
• Aliphatic polyamide resin (A) Polyamide resin (A-1): Polyamide 6, manufactured by UBE Co., Ltd. (relative viscosity: 2.2; melting point: 220° C.; MFR measured in accordance with ASTM D1238 at 230° C. and a load of 2.16 kg: 60.0 g/10 min; terminal amino group concentration: 3.3 ⁇ 10 ⁇ 5 eq/g)
• Example 1 As the first aliphatic polyamide resin (a1), 10.00% by mass of polyamide resin (A-1) was added with 2.50% by mass of maleic anhydride-modified ethylene / 1-hexene copolymer (B-1), and melt-kneaded at a cylinder temperature of 230 ° C., a screw rotation speed of 500 rpm, and a discharge rate of 75 kg / h using a twin-screw kneader ZSK32McPlus (manufactured by Coperion Co., Ltd., screw diameter 32 mm), and the first pellet was produced.
• the second pellet was produced using polyamide resin (A-2) as the second aliphatic polyamide resin (a2).
• the first pellet was 12.50% by mass
• the second pellet was 87.28% by mass
• the antioxidant was 0.10% by mass
• the compound (E) was 0.06% by mass
• the compound (F) 1 was 0.03% by mass
• the compound (F) 2 was 0.03% by mass to obtain a pellet mixture.
• the formulation of the pellet mixture of Example 1 is shown in Table 1.
• Unstretched polyamide film a The pellet mixture of Example 1 was used to prepare an unstretched polyamide film a having a thickness of 50 ⁇ m using a T-die film molding machine having an Ex diameter of 40 mm manufactured by Plastics Technology Research Institute Co., Ltd.
• Unstretched polyamide film b The pellet mixture of Example 1 was used with a T-die film molding machine with 40 mm ⁇ Ex manufactured by Plastics Technology Research Institute Co., Ltd. to produce an unstretched polyamide film b with a thickness of 30 ⁇ m.
• Examples 2 and 5 and Comparative Examples 1, 2, 4 and 5 Pellet mixtures and polyamide films a to b of Examples 2 and 5 and Comparative Examples 1, 2, 4 and 5 were obtained in the same manner as in Example 1, except that the types and ratios of each component were changed as shown in Table 1.
• Example 3 5.80% by mass of polyamide resin (A-1) as the first aliphatic polyamide resin (a1) was added with 2.50% by mass of maleic anhydride-modified ethylene / 1-hexene copolymer (B-1), and melt-kneaded using a twin-screw kneader ZSK32McPlus (manufactured by Coperion Co., Ltd., screw diameter 32 mm) at a cylinder temperature of 230 ° C., a screw rotation speed of 500 rpm, and a discharge rate of 75 kg / h to prepare a first pellet.
• a second pellet was prepared using polyamide resin (A-2) as the second aliphatic polyamide resin (a2).
• a third pellet was prepared using linear low-density polyethylene (D-1) as the polyolefin (D) having no functional group.
• D-1 linear low-density polyethylene
• a third pellet was prepared using linear low-density polyethylene (D-1) as the polyolefin (D) having no functional group.
• 8.30% by mass of the first pellet, 88.98% by mass of the second pellet, 2.50% by mass of the third pellet, 0.10% by mass of the antioxidant, 0.06% by mass of the compound (E), 0.03% by mass of the compound (F) 1, and 0.03% by mass of the compound (F) 2 were dry-blended to obtain a pellet mixture.
• the composition of the pellet mixture of Example 3 is shown in Table 1.
• Polyamide films a to b were obtained in the same manner as in Example 1, except that the pellet mixture of Example 3 was used.
• Example 4 The pellet mixture and polyamide films a to b of Example 4 were obtained in the same manner as in Example 3, except that the ratio of each component was changed as shown in Table 1.
• Comparative Example 3 Only pellets of polyamide resin (A-2) were used. 99.78% by mass of the pellets, 0.10% by mass of antioxidant, 0.06% by mass of compound (E), 0.03% by mass of compound (F) 1, and 0.03% by mass of compound (F) 2 were dry-blended to obtain a pellet mixture.
• the composition of the pellet mixture of Comparative Example 3 is shown in Table 1.
• the pellets used in Comparative Example 3 are shown in the second pellet column of Table 1.
• Polyamide films a to b were obtained in the same manner as in Example 1, except that the pellet mixture of Comparative Example 3 was used.
• Table 1 shows the formulations of Examples 1 to 5 and Comparative Examples 1 to 5 and various physical properties of the resulting polyamide resin compositions.
• the high-side and low-side melting peak temperatures refer to the top temperatures of the endothermic peaks observed in the ranges of 150 to 250°C and 70 to 120°C on the DSC curve, respectively.
• the high-side and low-side crystallization temperatures refer to the top temperatures of the exothermic peaks observed in the ranges of 120 to 200°C and 60 to 110°C on the DSC curve, respectively. "nd" in the columns for low-side melting peak temperature and low-side crystallization temperature indicates that no peaks were detected.
• Resin pressure and resin temperature in film molding When producing unstretched polyamide film a, the resin pressure and resin temperature at the outlet of the T-die film molding machine were measured. It was determined that a resin pressure of 0.5 to 4.5 MPa indicates good moldability, and a resin pressure of 1.0 to 4.0 MPa indicates particularly excellent moldability. By keeping the resin pressure within the above range, the production speed of film molding can be increased and resin leakage from the molding machine can be prevented.
• Haze value (haze rate) The haze value (haze ratio) of the unstretched polyamide film a was measured in accordance with ASTM D-1003 using a Haze Meter manufactured by Nippon Denshoku Industries Co., Ltd. It was determined that a haze ratio of 25% or less is practically acceptable, a haze ratio of 15% or less is excellent in transparency, and a haze ratio of 10% or less is particularly excellent in transparency.
• glossiness The glossiness (gloss value) of the unstretched polyamide film a was measured in accordance with ASTM D-523 using a digital variable angle glossmeter manufactured by Suga Test Instruments Co., Ltd. A glossiness value of 50% or more was judged to be satisfactory for practical use, 80% or more to be excellent in gloss, and 100% or more to be particularly excellent in gloss.
• Puncture test After storing the unstretched polyamide film a for one day at 23°C and 50% RH, the elongation at break and the maximum point load were measured under the same environment using a needle with a diameter of 1.0 ⁇ and a tip shape of 0.5R in accordance with JAS (P-1019). It was determined that a maximum point load of 6.0 N or more was practically acceptable, and that a maximum point load of 8.0 N or more represented particularly excellent puncture strength.
• Friction coefficient After storing the unstretched polyamide film a for one day at 23°C and 50% RH, the static and dynamic friction coefficients were each measured five times in the same environment in accordance with ASTM D-1894, and the average values were calculated. Note that the coefficient of friction in Comparative Example 3 was too high to measure. The pass criteria for the static and dynamic friction coefficients were set to 1.0 or less.
• the adhesive layer was made of Admer (registered trademark) LF128 (acid-modified polyolefin resin) manufactured by Mitsui Chemicals, Inc., and the polyethylene layer was made of F022NH (low-density polyethylene resin) manufactured by Ube Maruzen Polyethylene Co., Ltd.
• Admer registered trademark
• LF128 acid-modified polyolefin resin
• F022NH low-density polyethylene resin
• ⁇ The discharge of strands is stable, the transparency is good, the surface is not rough, and the recyclability is excellent.
• ⁇ The strands were discharged stably and maintained transparency despite some cloudiness. The strands had only slight roughness on their surfaces, and were recyclable.
• ⁇ At least one of the following conditions is met, and the recyclability is poor: the discharge of the strands is not stable, the strands are cloudy and lack transparency, and the strand surfaces are rough.
• compositions of Examples 1 to 5 provide films that are free from deterioration of appearance due to film gel, are excellent in transparency, gloss, mechanical strength, friction coefficient and pinhole resistance, and are also excellent in material recyclability.
• the compositions of Examples 1 to 5 contain 1 to 5 mass% of an ethylene/ ⁇ -olefin copolymer (B) having a functional group and 3 to 8 carbon atoms, and the DSC curve of the composition has a melting peak in the range of 150 to 205° C.
• a film is produced by melt-kneading a pellet mixture containing first pellets containing a first aliphatic polyamide resin (a1) and a copolymer (B) in a predetermined ratio; and second pellets containing a second aliphatic polyamide resin (a2).
• a film is produced by melt-kneading a pellet mixture containing, in addition to the first and second pellets, a third pellet containing a polyolefin (D) having no functional group.
• each component can be uniformly mixed, and not only can the occurrence of film gel be suppressed, but the film molding resin pressure is low and moldability is excellent.
• Comparative examples 1, 2, and 4 in which the content of functional group-containing ethylene/ ⁇ -olefin copolymer (B) having 3 to 8 carbon atoms exceeded 5% by mass, showed a high occurrence of film gels and poor material recyclability. Comparative examples 2 and 4 also showed poor film transparency and gloss. Comparative example 3, in which the resin component was only an aliphatic copolyamide, showed a high film friction coefficient and poor pinhole resistance and material recyclability in low-temperature environments.
• Comparative example 5 in which the content of functional group-containing ethylene/ ⁇ -olefin copolymer (B) having 3 to 8 carbon atoms was 1 to 5% by mass but the aliphatic polyamide resin only contained an aliphatic homopolyamide, showed poor film elongation, flexibility, pinhole resistance in low-temperature environments, and material recyclability.
• the film obtained from the polyamide resin composition of the present invention is particularly suitable for use in food packaging applications, and is useful because it has excellent material recyclability for the waste film.

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