Masterbatch resin composition for food packaging materials, thermoplastic resin composition for food packaging materials and food packaging materials

Abstract

To provide a food packaging material with excellent freshness preservation performance and superior appearance characteristics, free from color changes and blemishes. Furthermore, to provide a masterbatch resin composition and a thermoplastic resin composition for food packaging materials that have excellent processability and are used in the manufacture of the food packaging material. [Solution] The problem is solved by a masterbatch resin composition for food packaging materials, comprising a polyolefin resin (A), a basic filler (B) having a pH of 10.0 to 13.0 in water and a water content of 20,000 ppm or less, and an antioxidant (C) selected from the group consisting of hindered amine antioxidants, hydroxylamine antioxidants, and phosphorus antioxidants, wherein the content of antioxidant (C) is 0.1 to 450 parts by mass per 100 parts by mass of basic filler (B), and the content of basic filler (B) is 3 to 50% by mass based on 100% by mass of the masterbatch resin composition.

Description

[Technical Field]

[0001] This disclosure relates to a masterbatch resin composition for food packaging materials, a thermoplastic resin composition for food packaging materials, and food packaging materials. [Background technology]

[0002] In recent years, there has been a growing demand to extend the shelf life of food products from the perspective of reducing food waste. However, conventional food packaging materials alone are insufficient to suppress the growth of microorganisms in food, and prolonged storage can lead to deterioration and spoilage of the food. Therefore, measures such as incorporating freshness-preserving agents inside food packaging materials are being taken.

[0003] In particular, for fresh foods such as fish, vegetables, and fruits, measures are being considered to impart antibacterial properties and carbon dioxide absorption capabilities to the food packaging materials themselves as a way to maintain freshness.

[0004] As an example of such technology, Patent Document 1 describes a method for creating a food packaging material with excellent freshness preservation properties by incorporating calcium hydroxide powder, which is a basic filler, into a thermoplastic resin. Patent Document 2 describes a technology for a film that prevents deterioration of color and contamination of processing machines by incorporating alkaline earth metal hydroxides and phenolic antioxidants into a polypropylene resin.

[0005] Polyolefin resins have become commonly used in recent years due to their high processability, appearance, chemical resistance, and excellent suitability for food packaging applications. Polyolefin resins are typically heated, melted, and kneaded using an extruder or similar machine at processing temperatures of 150 to 300°C, then pelletized and processed into food packaging materials. Furthermore, basic fillers are known to inhibit the growth of microorganisms when in contact with food, thereby preserving the freshness of the food. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2017-30842 [Patent Document 2] Japanese Patent Publication No. 2001-247728 [Overview of the project] [Problems that the invention aims to solve]

[0007] When using a masterbatch resin composition as a manufacturing method for food packaging materials, the dispersion process occurs in two stages, during manufacturing and during molding. Compared to using a compound, this involves more dispersion steps overall, and it is preferable to use a masterbatch resin composition because the basic filler is more easily dispersed. As a result, food packaging materials molded using a masterbatch resin composition have superior film-forming properties, a smoother appearance, and better freshness preservation performance compared to those made with a compound. However, polyolefin resins have the problem of decomposing due to heat during processes such as extrusion. In particular, when attempting to incorporate high concentrations of basic fillers into food packaging materials to improve freshness retention, this can accelerate the degradation of polyolefin resins during pellet processing and molding of food packaging materials, negatively affecting the processability of pellets and the film-forming properties of food packaging materials. Furthermore, the degradation of polyolefin resins can worsen the appearance of food packaging materials, such as discoloration and the formation of blemishes during film formation. This problem is more pronounced in masterbatch resin compositions containing higher concentrations of basic fillers, and there is a need to improve the processability of masterbatch resin compositions.

[0008] This disclosure has been made in view of the circumstances described above, and aims to provide a food packaging material that has excellent freshness preservation performance and appearance characteristics free from color changes and blemishes. Furthermore, it aims to provide a masterbatch resin composition and a thermoplastic resin composition for food packaging materials that have excellent processability and can be used in the manufacture of the food packaging material. [Means for solving the problem]

[0009] In order to solve the above problems, the inventors diligently conducted research and, as a result, discovered a masterbatch resin composition for food packaging materials having the configuration shown below, and completed the present invention.

[0010] In other words, some embodiments of this disclosure are as follows: <1> A masterbatch resin composition comprising a polyolefin resin (A), a basic filler (B), and an antioxidant (C), Basic filler (B) has a pH of 10.0 to 13.0 in water and a water content of 20,000 ppm or less. Antioxidant (C) is at least one selected from the group consisting of hindered amine antioxidants, hydroxylamine antioxidants, and phosphorus antioxidants. The content of antioxidant (C) is 0.1 to 450 parts by mass per 100 parts by mass of basic filler (B). The content of basic filler (B) is 3 to 50% by mass, based on 100% by mass of the masterbatch resin composition. Masterbatch resin composition for food packaging materials. <2> The basic filler (B) is at least one selected from the group consisting of calcium oxide, calcium hydroxide, magnesium carbonate, and magnesium hydroxide. <1> The masterbatch resin composition for food packaging materials described above. <3> The average particle size of the basic filler (B) is 10.0 μm or less. <1> or <1> The masterbatch resin composition for food packaging materials described above. <4> The antioxidant (C) content is 0.01 to 5% by mass, based on 100% by mass of the masterbatch resin composition. <1> ~ <3> A masterbatch resin composition for food packaging materials as described in any of the following. <5> ; <1> ~ <4> A thermoplastic resin composition for food packaging materials comprising any of the masterbatch resin compositions for food packaging materials described herein, and a main resin (D). <6>; The content of the basic filler (B) is 0.1 to 20% by mass based on 100% by mass of the thermoplastic resin composition for food packaging materials described in <5>. <7>; A compound containing a polyolefin resin (A), a basic filler (B), and an antioxidant (C), The basic filler (B) has a pH in water of 10.0 to 13.0 and a moisture content of 20,000 ppm or less, The antioxidant (C) is at least one selected from the group consisting of a hindered amine-based antioxidant, a hydroxylamine-based antioxidant, and a phosphorus-based antioxidant, The content of the antioxidant (C) is 0.1 to 450 parts by mass with respect to 100 parts by mass of the basic filler (B), The content of the basic filler (B) is 0.1 to 20% by mass based on 100% by mass of the compound, Compound for food packaging materials. <8>; A food packaging material formed from the thermoplastic resin composition for food packaging materials described in <5> or <6> or the compound described in <7>. <8>; A method for producing a thermoplastic resin composition for food packaging materials, comprising a step of melt-kneading the masterbatch resin composition for food packaging materials described in any one of <1> to <4> and the main resin (D). Method.

Advantages of the Invention

[0011] According to one embodiment of the present disclosure, an object is to provide a food packaging material having excellent freshness retention performance and appearance characteristics. Furthermore, a masterbatch resin composition for food packaging materials and a thermoplastic resin composition for food packaging materials having excellent processability, which are used in the production of the food packaging material, can be provided.

Modes for Carrying Out the Invention

[0012] [[ID=�3]] The present disclosure will be described in detail below. It goes without saying that other embodiments are also included in the scope of the present invention, as long as they are consistent with the spirit of the present invention. Furthermore, numerical ranges specified using "~" in this specification include the numerical values ​​before and after "~" as the lower and upper limits. In addition, "film" and "sheet" are not distinguished by thickness in this specification. In other words, "sheet" in this specification includes thin film-like materials, and "film" in this specification includes thick sheet-like materials. A masterbatch resin composition is a resin composition in which a high concentration of additives is dispersed in a resin, and it plays a role in imparting functionality to a plastic molded product when mixed with the main resin at a specified ratio during the formation of the molded product. In this disclosure, "masterbatch resin composition for food packaging materials" may also be referred to as "masterbatch resin composition," and "thermoplastic resin composition for food packaging materials" may also be referred to as "thermoplastic resin composition" or "resin composition." Unless otherwise noted, the various components mentioned herein may be used individually or in combination of two or more. The numerical values ​​specified herein are those obtained by the methods disclosed in the embodiments or examples.

[0013] <Masterbatch resin composition for food packaging materials> The masterbatch resin composition according to this embodiment comprises a polyolefin resin (A), a basic filler (B), and an antioxidant (C). The basic filler (B) has a pH of 10.0 to 13.0 in water and a water content of 20,000 ppm or less. The antioxidant (C) is at least one selected from the group consisting of hindered amine antioxidants, hydroxylamine antioxidants, and phosphorus antioxidants. The content of the antioxidant (C) is 0.1 to 450 parts by mass per 100 parts by mass of the basic filler (B), and the content of the basic filler (B) is 3 to 50% by mass based on 100% by mass of the masterbatch resin composition. By using such a masterbatch resin composition for food packaging materials, processability is excellent even when a high concentration of basic filler is included, and the resulting food packaging material can have excellent freshness preservation performance and superior color and appearance characteristics.

[0014] This embodiment will be described in detail below. (Polyolefin resin (A)) The polyolefin resin (A) in the present invention is a polymer of olefin monomers such as ethylene, propylene, and butylene, and may be a block copolymer, a random copolymer, a bipolymer, or a terpolymer. Specifically, examples include polymers of α-olefins such as linear low-density polyethylene resin (LLDPE), low-density polyethylene resin (LDPE), high-density polyethylene resin (HDPE), and polypropylene resin (PP). From the viewpoint of moldability, the polyolefin resin (A) preferably has a melt flow rate (MFR) value of 0.01 g / 10 min or more and 10 g / 10 min or less at 190°C and a 2.16 kg load. Here, the MFR is the value measured at a heating temperature of 190°C and a 2.16 kg load in accordance with the conditions D of Annex A Table D of JIS K7210:1999, and the unit is g / 10 min.

[0015] Specific examples of polyolefin resin (A) include Suntec HD J300 (HDPE, manufactured by Asahi Kasei Corporation), Suntec LD F1810 (LDPE, manufactured by Asahi Kasei Corporation), Nipolon L F13 (LLDPE, manufactured by Tosoh Corporation), and Novatec PP FA3EB (PP, manufactured by Nippon Polypropylene Co., Ltd.).

[0016] The content of polyolefin resin (A) is preferably 20 to 96.99% by mass, and more preferably 49 to 95.0% by mass, based on 100% by mass of the masterbatch resin composition. From the viewpoint of extrusion processability of pellets and film-forming properties of food packaging materials, the lower limit of the polyolefin resin (A) content is preferably 20% by mass or more.

[0017] (Basic filler (B)) Basic filler (B) is a basic filler with a pH of 10.0 to 13.0 in water and a water content of 20,000 ppm or less. Basic filler (B) prevents fermentation and spoilage by bacteria, and imparts a freshness-preserving function to molded bodies obtained from masterbatch resin compositions.

[0018] The basic filler (B) has a pH of 10.0 to 13.0 in water, and from the viewpoint of achieving both excellent processability and a balance between freshness preservation performance and appearance characteristics for food packaging materials, a pH of 11.0 to 12.5 is preferred. From the standpoint of freshness preservation performance, a pH of 11.0 to 13.0, 12.0 to 13.0, or 12.5 to 13.0 is more preferable. From the viewpoint of moldability and appearance characteristics, a pH of 10.0 to 12.5 is more preferable. If the pH of the basic filler (B) becomes too high, it may cause the generation of foreign matter or discoloration during the kneading of the thermoplastic resin composition, and may also affect the moldability of the thermoplastic resin composition.

[0019] In this disclosure, the pH of the basic filler is the pH value measured at 23°C using a pH meter. A pH meter such as the HM-30P manufactured by Toa DKK Corporation can be used. If the basic filler is soluble in water, the pH can be measured using an aqueous solution; if it is not soluble in water, the pH can be measured using the supernatant of the dispersion. Specifically, for example, 0.5 g of basic filler can be weighed, placed in a plastic container, 50 ml of deionized water added, vibrated with a vibrator for 30 minutes, then separated into solid and liquid using a centrifuge, and the supernatant water stabilized in a 23°C constant temperature bath. The pH of the supernatant water can then be measured with a pH meter (HM-30P pH meter manufactured by Toa DKK Co., Ltd.) and this value can be used as the pH of the basic filler.

[0020] The basic filler (B) has a moisture content of 20,000 ppm or less, preferably 15,000 ppm or less, more preferably 10,000 ppm or less, even more preferably 5,000 ppm or less, and particularly preferably 2,000 ppm or less, from the viewpoint of appearance characteristics and moldability. The higher the moisture content, the stronger the basicity, which accelerates the deterioration of the resin and may lead to deterioration of moldability and discoloration. The moisture content can be reduced to 20,000 ppm or less by drying in an oven or the like. The oven temperature is preferably 80 to 100°C.

[0021] The water content of basic fillers can be determined by the Karl Fischer method. For example, using the Karl Fischer method, a basic filler is heated, and Karl Fischer reagent is added dropwise to the resulting water. The water content can then be calculated from the volume of reagent added up to the endpoint. For example, a Karl Fischer trace moisture analyzer manufactured by Hiranuma Sangyo Co., Ltd. can be used as a moisture content analyzer. A 0.5g sample is weighed out, the measurement temperature is set to 150°C, and the moisture content can be determined by quantifying the amount of moisture under vaporization conditions for 30 minutes.

[0022] The basic filler (B) is not particularly limited as long as it has a pH of 10.0 to 13.0 in water and a water content of 20,000 ppm or less; generally available basic fillers can be used. Examples include basic compounds containing alkali metals or alkaline earth metals, zeolites that release alkali metal or alkaline earth metal ions, or ion-releasing fillers, hydrotalcite, etc.

[0023] Basic compounds containing alkali metals or alkaline earth metals include carbonates, bicarbonates, silicates, phosphates, oxides, hydroxides, etc. Examples include sodium carbonate, potassium carbonate, calcium carbonate, magnesium carbonate, sodium bicarbonate, potassium bicarbonate, sodium silicate, potassium silicate, calcium silicate, magnesium silicate, sodium phosphate, calcium oxide, calcium hydroxide, magnesium hydroxide, etc.

[0024] As zeolites that release alkali metal and alkaline earth metal ions, various natural or synthetic zeolites containing alkali metal and alkaline earth metal ions as exchangeable ions can be used.

[0025] Examples of ion-releasing fillers include oxide glasses such as aluminosilicate glass containing alkali metals or alkaline earth metals, borosilicate glass, and soda lime glass, as well as fluoride glasses such as zirconium fluoride glass.

[0026] In particular, basic compounds containing alkali metals or alkaline earth metals are preferred from the viewpoint of achieving both freshness preservation performance and appearance characteristics and moldability. The basic compound containing alkali metals or alkaline earth metals is more preferably a carbonate, oxide, or hydroxide, and even more preferably calcium oxide, calcium hydroxide, magnesium carbonate, calcium carbonate, or magnesium hydroxide. Particularly preferred are calcium oxide, calcium hydroxide, magnesium carbonate, or magnesium hydroxide.

[0027] The basic filler (B) content is 3 to 50% by mass, more preferably 4 to 45% by mass, based on 100% by mass of the masterbatch resin composition. A content of 3% by mass or more enhances the freshness preservation effect of the food packaging material. Furthermore, a content of 50% by mass or less suppresses resin degradation and dispersion problems, resulting in a food packaging material with excellent processability, reduced discoloration and blemishes, and superior appearance.

[0028] From the viewpoint of appearance characteristics and moldability, the average particle size of the basic filler (B) is preferably 10.0 μm or less, more preferably 0.1 to 10.0 μm, and even more preferably 0.1 to 5.0 μm. In this specification, the average particle size of the basic filler (B) is determined by observing 100 particles randomly using a transmission electron microscope, measuring the distance between the two furthest points on the outer shape of each particle based on the length of the micron marker on the screen, and averaging the results.

[0029] (Antioxidant (C)) The antioxidant (C) is at least one selected from the group consisting of hindered amine antioxidants, hydroxylamine antioxidants, and phosphorus antioxidants. By using hindered amine antioxidants and hydroxylamine antioxidants as antioxidants (C), the pelletization of masterbatch resin compositions and the formation of food packaging materials can be performed. It can exhibit excellent moldability during shaping. Furthermore, by using a phosphorus-based antioxidant (C) as the antioxidant, even when the masterbatch resin composition of the present invention contains a high concentration of basic filler, discoloration due to oxidative degradation of the resin is prevented, resulting in excellent discoloration resistance.

[0030] [Hindered amine antioxidants] Hindered amine antioxidants, derivatives of 2,2,6,6-tetramethylpiperidine, for example, 1-[2-[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionyloxy]ethyl]-4-[3-3,5-di-t-butyl-4-hydroxyphenyl)propionyloxy]-2,2,6,6-tetramethylpiperidine, 2-(3,5-di-t-butyl-4-hydroxybenzyl)-2-n-butylmalonic acid-bis-(1,2,2,6,6-pentamethyl-4-piperidyl), N,N',N'',N'''-tetrakis-(4,6-bis(butyl-(N-methyl-2,2,6,6-tetramethylpiperidine-4-yl)amino)-triazine-2-yl)-4,7-di Azadecane-1,10-amine, bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis(N-methyl-2,2,6,6-tetramethyl-4-piperidyl) sebacate, (2,2,6,6-tetramethyl-4-piperidyl / tridecyl)-1,2,3,4-butanetetracarboxylate, (1,2,2,6,6-pentamethyl-4-piperidyl / tridecyl)-1,2,3,4-butanetetracarboxylate, polycondensate of dibutylamine·2,4,6-trichloro-1,3,5-triazine·N,N-bis(2,2,6,6-tetramethyl-4-piperidyl-1,6-hexamethylenediamine·N-(2,2,6,6-tetramethyl-4-piperidyl)butylamine, Dibutylamine·1,3,5-triazine·N,N-bis(2,2,6,6-tetramethyl-4-piperidyl-1,6-hexamethylenediamine·N-(2,2,6,6-tetramethyl-4-piperidyl)butylamine polycondensate, Poly[{(1,1,3,3-tetramethylbutyl)amino-1,3,5-triazine-2,4-diyl}{(2,2,6,6-tetramethyl-4-piperidyl)imino}hexamethylene{(2,2,6,6-tetramethyl-4-piperidyl)imino}], polycondensate of 1,6-hexanediamine-N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl) and morpholin-2,4,6-trichloro-1,3,5-triazine, Poly[(6-morpholino-s-triazine-2,4-diyl)[(2,2,6,6-tetramethyl-4-piperidyl)imino]-hexamethylene[(2,2,6,6-tetramethyl-4-piperidyl)imino], polymer of dimethyl succinate and 4-hydroxy-2,2,6,6-tetramethyl-1-piperidineethanol, A mixed ester of 1,2,3,4-butanetetracarboxylic acid, 1,2,2,6,6-pentamethyl-4-piperidinol, and 3,9-bis(2-hydroxy-1,1-dimethylethyl)-2,4,8,10-tetraoxaspiro[5,5]undecane. Poly[{6-[(1,1,3,3-tetramethylbutyl)amino]-S-triazine-2,4-diyl}{(2,2,6,6-tetramethyl-4-piperidyl)imino}-hexamethylene-{(2,2,6,6-tetramethyl-4-piperidyl)imino}], a mixture of tetramethylpiperidine fatty acid ester (50%) and polypropylene wax (50%), 4-benzoyloxy-2,2,6,6-tetramethylpiperidine These are some examples.

[0031] Among hindered amine antioxidants, from the viewpoint of imparting processing stability and long-term thermal stability to thermoplastic resin compositions, for example, bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate, dibutylamine·1,3,5-triazine·N,N-bis(2,2,6,6-tetramethyl-4-piperidyl-1,6-hexamethylenediamine·N-(2,2,6,6-tetramethyl-4-piperidyl)butylamine polycondensation Product, poly[{6-[(1,1,3,3-tetramethylbutyl)amino]-S-triazine-2,4-diyl}{(2,2,6,6-tetramethyl-4-piperidyl)imino}-hexamethylene-{(2,2,6,6-tetramethyl-4-piperidyl)imino}], mixture of tetramethylpiperidine fatty acid ester (50%) and polypropylene wax (50%), 4-benzoyloxy-2,2,6,6-tetramethylpiperidine The like are preferable.

[0032] [Hydroxylamine-based antioxidants] Examples of hydroxylamine antioxidants include N,N-dibenzylhydroxylamine, N,N-diethylhydroxylamine, N,N-dioctylhydroxylamine, N,N-dilaurylhydroxylamine, N,N-didodecylhydroxylamine, N,N-ditetradecylhydroxylamine, and other N-di(C1~C) 15 Alkyl)hydroxylamine, N,N-dihexadecylhydroxylamine, N,N-dioctadecylhydroxylamine, N-hexadecyl-N-tetradecylhydroxylamine, N-hexadecyl-N-heptadecylhydroxylamine, N-hexadecyl-N-octadecylhydroxylamine, N-heptadecyl-N-octadecylhydroxylamine, N-methyl-N-octadecylhydroxylamine, etc. 16 ~C 18 Alkyl)hydroxylamines are examples. From the viewpoint of processability and appearance characteristics, N,N-(C) 16 ~C 18 It is an alkyl hydroxylamine.

[0033] [Phosphorus-based antioxidants] Phosphorus-based antioxidants are organic compounds containing a phosphorus atom. Preferably, phosphorus-based antioxidants contain a trivalent phosphorus atom, and more preferably, phosphite esters or phosphonic acid esters. Examples of phosphorus-based antioxidants include bis(2,4-di-t-butylphenyl)pentaerythrityl diphosphite, tetrakis(2,4-di-butylphenyl)-4,4'-biphenylene-di-phosphonite, bis(2,6-di-t-butyl-4-methylphenyl)pentaerythrityl diphosphite, bis(2,4-di-t-butyl-6-methylphenyl)ethyl phosphite, and tetrakis(2,4-di-butyl-5-methylphenyl) (phenyl)-4,4'-biphenylene-di-phosphonite, bis(2,4-dicumylphenyl)pentaerythrityl diphosphite, 2,4,8,10-tetra-t-butyl-6-(2-ethylhexyloxy)-12H-dibenzo[d,g][1,3,2]dioxaphosphosine, tris(2,4-di-t-butylphenyl) phosphite or tris(mono or dinonylphenyl) phosphite, distearyl pentaerythritol Diphosphite, bis(2,4-di-t-butylphenyl)pentaerythritol diphosphite, 2,2'-methylenebis(4,6-di-t-butylphenyl)-2-ethylhexyl phosphite, cyclic neopentanetetraylbis(2,6-t-butyl-4-methylphenyl phosphite), bis(2,4-diquylphenyl)pentaerythritol diphosphite, 2,2',2''-nitrilo[triethyl-tris(3,3',5,5'-tetra-t-butyl-1,1'-biphenyl-2,2'-diyl)] phosphite, 6-[3-(3-t-butyl-4-hydroxy-5-methylphenyl)propoxy]-2,4,8,10-tetra-t-butyldibene [df][1.3.2]dioxaphosfepine, 2.10-dimethyl-4,8-di-t-butyl-6-[3-(3,5-di-t-butyl-4-hydroxyphenyl)propoxy]-12H-dibenzo[dg][1.3.2]dioxaphosphosine, 24.8.10-tetra-t-pentyl-6-[3-(3,5-di-t-butyl-4-hydroxyphenyl)propoxy]-12-methyl-12H-dibenzo[dg][1.3.2]dioxaphosphosine, 2.10-dimethyl-4,8-di-t-butyl-6-[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionyloxy]-12H-dibenzo[dg][1.3.2]dioxaphosphosine, 2.4.8.10-Tetra-t-butyl-6-[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionyloxy]-dibenzo[dg][1,3.2]dioxaphosfepine, 2,10-dimethyl-4,8-di-t-butyl-6-(3,5-di-t-butyl-4-hydroxybenzoyloxy)-12H-dibenzo[dg][1.32]dioxaphosphosine, 2,4,8,10-tetra-t-butyl-6-(3,5-di-t-butyl-4-hydroxybenzoyloxy)-12-methyl-12H-dibenzo[dg][1.3.2]dioxaphosphosine, 210-dimethyl-4,8 Examples include -di-t-butyl-6-[3-(3-methyl-4-hydroxy-5-t-butylphenyl)propoxy]-12H-dibenzo[dg][1.3.2]dioxaphosphosine, 2,4,8,10-tetra-t-butyl-6-[3-(3,5-di-t-butyl-4-hydroxyphenyl)propoxy]-12H-dibenzo[dg][1.3.2]dioxaphosphosine, and 2,4,8,10-tetra-t-butyl-6-[2,2-dimethyl-3-(3-t-butyl-4-hydroxy-5-methylphenyl)propoxy]-dibenzo[df][1,3,2]dioxaphosfepine.

[0034] The masterbatch resin composition of the present invention preferably contains a total of 0.001 to 20% by mass of one or more antioxidants (C) based on 100% by mass of the masterbatch resin composition, more preferably 0.01 to 10% by mass, even more preferably 0.01 to 5% by mass, and particularly preferably 0.05 to 3% by mass. Being within this range allows for superior extrusion processability and film-forming properties. Furthermore, if the antioxidant (C) content is 0.001% by mass or more, the antioxidant effect is superior, and deterioration and yellowing of the polyolefin resin and antioxidant can be suppressed. If it is 20% by mass or less, the cause of breakage during film formation is suppressed, and the dispersibility in the composition is superior, so that the cause of appearance defects such as the occurrence of blemishes in inflation films can be suppressed.

[0035] The content of antioxidant (C) is 0.1 to 450 parts by mass per 100 parts by mass of basic filler (B). From the viewpoint of moldability and hue, the lower limit is preferably 0.4 parts by mass, and more preferably 0.5 parts by mass. From the viewpoint of moldability and film material, the upper limit is preferably 400 parts by mass, more preferably 300 parts by mass, more preferably 200 parts by mass, more preferably 100 parts by mass, more preferably 50 parts by mass, and even more preferably 10 parts by mass.

[0036] (Other ingredients) The masterbatch resin composition may optionally contain other components such as additives. Examples of additives include antioxidants other than antioxidant (C), dispersants, lubricants (higher fatty acid metal salts, waxes, etc.), surfactants, antistatic agents, flame retardants, UV absorbers, fillers, and pigments. The selection of other optional components and their amounts are not particularly limited, as long as they can solve the problems of one embodiment of the present invention. Multiple additives may be used in combination. Furthermore, the masterbatch resin composition may partially contain resins other than polyolefin resin (A) as long as they do not hinder the effects of one embodiment of the present invention.

[0037] Masterbatch resin compositions can be colored with pigments to produce molded articles with excellent heat-shielding properties or easily identifiable molded articles. The pigments are not particularly limited and can be those that are generally available, but from the viewpoint of the natural environment, it is preferable that they are substantially free of pigments containing cadmium, lead, chromium, arsenic, mercury, copper, selenium, nickel, molybdenum, and fluorine.

[0038] For example, when a masterbatch resin composition contains a pigment, it is preferable to use a dispersant to disperse the pigment, and examples of dispersants include fatty acid metal salts. The fatty acid component of the fatty acid metal salt is preferably a chain-like carboxylic acid having 6 to 30 carbon atoms, and may be linear or branched, and may have only saturated bonds or only unsaturated bonds. Examples of fatty acids include caproic acid, caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, palmitoleic acid, stearic acid, behenic acid, oleic acid, erucic acid, linoleic acid, and montanic acid. Preferably, the metals are elements from Group 1, Group 2, Group 12, and Group 13, with elements from Group 1 or Group 2 being more preferred. Specific examples include sodium, potassium, calcium, magnesium, and barium.

[0039] Examples of fatty acid metal salts include calcium stearate, magnesium stearate, barium stearate, calcium laurate, magnesium laurate, and sodium montantate. These may be used individually or in combination of two or more. Among these, calcium stearate, magnesium stearate, calcium laurate, and magnesium laurate are preferred.

[0040] (Method for producing masterbatch resin composition) The method for producing the masterbatch resin composition of this embodiment is not particularly limited, but it can be produced by kneading a basic filler (B) and an antioxidant (C) at the temperature at which the polyolefin resin (A) melts. Specifically, for example, a polyolefin resin (A), a basic filler (B), an antioxidant (C), and various additives as needed are added and mixed and melt-kneaded in a batch-type kneader such as a kneader, roll mill, super mixer, high-speed mixer, ball mill, sand mill, attritor, or Banbury mixer, a single-screw extruder, a twin-screw extruder, a rotor-type twin-screw kneader, etc. to produce a thermoplastic resin composition in the form of pellets, powders, granules, or beads. It is preferable to produce pellets using a single-screw or twin-screw extruder because it has strong kneading power and facilitates subsequent molding.

[0041] <Thermoplastic resin composition for food packaging materials> The thermoplastic resin composition for food packaging materials of the present invention comprises a polyolefin resin (A), a basic filler (B), and an antioxidant (C). The thermoplastic resin composition may be prepared by melt-kneading a masterbatch resin composition and a main resin (D), or it may be a compound prepared by melt-kneading a polyolefin resin (A), a basic filler (B), and an antioxidant (C) without going through the masterbatch resin composition. In the case of a compound, polyolefin resin (A) becomes the main resin of the thermoplastic resin composition. From the viewpoint of freshness preservation performance, the content of basic filler (B) is preferably 0.1 to 20% by mass, and more preferably 0.5 to 20% by mass, based on 100% by mass of the thermoplastic resin composition for food packaging materials.

[0042] In other words, the compound comprises a basic filler (B) with a pH of 10.0 to 13.0 in water and a water content of 20,000 ppm or less, and an antioxidant (C) which is at least one selected from the group consisting of hindered amine antioxidants, hydroxylamine antioxidants, and phosphorus antioxidants. The content of antioxidant (C) is 0.1 to 450 parts by mass per 100 parts by mass of basic filler (B), and the content of basic filler (B) may be 0.1 to 20% by mass based on 100% by mass of the compound. From the viewpoint of freshness preservation performance, it is more preferably 0.5 to 20% by mass.

[0043] Typically, masterbatches involve a dispersion process in two stages, during manufacturing and during molding. Compared to compounds, masterbatches have more overall dispersion steps, making it preferable to use a masterbatch resin composition because the basic filler (B) is more easily dispersed. As a result, food packaging materials molded using a masterbatch resin composition have superior film-forming properties, a smooth appearance without blemishes, and excellent freshness preservation performance compared to those using compounds. Therefore, from the standpoint of dispersibility, stronger shear kneading is desirable when manufacturing compounds, but when kneading high concentrations of basic fillers into food packaging materials, strong shear kneading is not recommended. It is preferable to use a masterbatch resin composition because it may accelerate the degradation of polyolefin resins.

[0044] Furthermore, it is preferable to gradually reduce the concentration of the basic filler (B) by first forming a masterbatch resin composition with a high concentration of basic filler (B) and then melt-kneading it, followed by further melt-kneading with the main resin (D). This process allows the basic filler (B) to be uniformly distributed in the masterbatch resin composition and dispersed stably.

[0045] The thermoplastic resin composition can be obtained in the form of pellets, powder, granules, or beads, with pellets or powder being preferred, and pellets being more preferred.

[0046] Mixing equipment for producing thermoplastic resin compositions can include, for example, mixing with a Henschel mixer, tumbler, disper, etc., and batch kneaders such as kneaders, roll mills, super mixers, Henschel mixers, Shugi mixers, vertical granulators, high-speed mixers, fur matrices, ball mills, steel mills, sand mills, vibratory mills, attritors, Banbury mixers, twin-screw extruders, single-screw extruders, rotor-type twin-screw kneaders, etc. In the present invention, from the viewpoint of producing a uniform dispersion, it is preferable to use a batch kneader or a twin-screw extruder.

[0047] When producing a thermoplastic resin composition using a masterbatch resin composition, the process includes a step of melting and kneading the masterbatch resin composition and the main resin (D). From the viewpoint of achieving both freshness preservation performance, appearance characteristics, and moldability, the masterbatch resin composition is preferably blended in an amount of 0.1 to 50 parts by mass, and more preferably 0.2 to 45 parts by mass, per 100 parts by mass of the main resin (D). From the viewpoint of freshness preservation performance, it is more preferably 0.3 to 45 parts by mass.

[0048] (Main resin (D)) In the present invention, the main resin (D) is a resin that forms the base of a thermoplastic resin composition, which is used by mixing it with a masterbatch resin composition during molding. The main resin (D) can be any conventionally known thermoplastic resin, but it is preferably a polyolefin resin (A), and the same polyolefin resin described as polyolefin resin (A) can be used. Specifically, examples include polymers of α-olefins such as linear low-density polyethylene resin (LLDPE), low-density polyethylene resin (LDPE), high-density polyethylene resin (HDPE), and polypropylene resin (PP). The main resin (D) does not have to be the same resin as the polyolefin resin (A) used in the masterbatch resin composition, but from the viewpoint of compatibility, it is preferable that it be the same type of polyolefin resin. That is, if the polyolefin resin (A) is HDPE, it is preferable that the main resin (D) is also HDPE.

[0049] <Food packaging materials> The food packaging material is a molded article formed from the thermoplastic resin composition for food packaging materials of the present invention. The form of the food packaging material is not particularly limited, but examples include film (sheet), tube, bag, plate, and three-dimensional structure. For example, if the packaging material is in the form of a bag, it may be a packaging material directly formed from the resin composition, or it may be a packaging material obtained by further processing a molded article that has been processed from the resin composition into a film or tube. The method for further processing a molded article that has been formed from the resin composition into a film or tube into a bag is not particularly limited, but for example, heat sealing by a heat sealer This includes processes such as welding, bonding with adhesives, and processing using bag-making machines for pillow packaging, stretch packaging, blister packaging, etc.

[0050] When food packaging materials are to be made into films, the above thermoplastic resin composition can be formed into films by known film molding methods. For example, the inflation method (circular die method) or T-die method, which are melt extrusion methods, can be used. Other methods such as casting, calendering, and pressing may also be used. Furthermore, the obtained film may be further stretched uniaxially or biaxially to improve transparency and strength. When forming a film, it does not necessarily have to be a single-layer film, but a laminated film (multilayer film) made by laminating two or more films made of the above resin may also be used.

[0051] Furthermore, in the case of film-like food packaging materials, the thickness of the film is not particularly limited, but is usually 5 to 200 μm, preferably 10 to 60 μm, and more preferably about 20 to 40 μm.

[0052] Furthermore, when food packaging materials are to be in the shape of containers such as bottles, the above-mentioned thermoplastic resin composition can be processed into any container shape such as bottles or trays by molding means such as blow molding, injection molding, or vacuum molding.

[0053] Furthermore, if the food packaging material is a film or similar, in addition to being a bag-shaped food packaging material that contains the food itself as described above, it is also possible to use a food packaging material in which the food is placed in a container such as a tray, and the top or opening of this container is covered with the film to seal it.

[0054] From the viewpoint of freshness preservation performance, the content of basic filler (B) is preferably 0.1 to 20% by mass, based on 100% by mass of the food packaging material. More preferably 0.5 to 2% by mass. It is 0% by mass. [Examples]

[0055] Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to the examples. In the examples and comparative examples, "parts" and "%" represent "parts by mass" and "mass %" respectively, and "RH" means relative humidity, unless otherwise specified. Note that the blanks in the table indicate that they are not blended.

[0056] The measurement methods for the pH, moisture content, and average particle size of the basic filler are as follows. <pH measurement> Weigh 0.5 g of the basic filler and put it into a plastic container. Add 50 ml of deionized water and vibrate it with a vibrator for 30 minutes. Then, perform solid-liquid separation with a centrifuge. After stabilizing the temperature of the supernatant water in a constant temperature bath at 23°C, measure the pH with a pH meter (pH meter HM-30P manufactured by Toa DKK Corporation).

[0057] <Moisture content of basic filler> Weigh 0.5 g of the sample, set the measurement temperature to 150°C, and measure it by the Karl Fischer method using a Karl Fischer micro moisture measuring device manufactured by Hiranuma Sangyo Co., Ltd. under the vaporization conditions for 30 minutes.

[0058] <Method for measuring average particle size of basic filler> Observe the basic filler with a transmission electron microscope JEM-1010 manufactured by JEOL Ltd. Randomly observe 100 particles, measure the distance between the two farthest points on the outer shape of each particle based on the length of the micron marker on the screen, and calculate the average.

[0059] The materials used in the examples and comparative examples are listed below. (Polyolefin resin (A)) (A-1): Novatec PP FA3EB (PP) (A-2): Suntech LD F1810 (LDPE) (A-3): Suntech HD J300 (HDPE) (A-4): Nipolon L F13 (L-LDPE)

[0060] (Basic filler (B), etc.) (B-1): Calcium hydroxide from manufacturing example 1, pH 12.5, moisture content 2,000 ppm, average particle size: 4.9 μm (B-2): Calcium oxide from manufacturing example 2, pH 12.5, moisture content 4,000 ppm, average particle size: 5.0 μm (B-3): Calcium oxide from manufacturing example 3, pH 12.5, moisture content 18,000 ppm, average particle size: 30.0 μm (B-4): Magnesium carbonate from manufacturing example 4, pH 10.0, moisture content 2,000 ppm, average particle size: 3.0 μm (B-5): Calcium carbonate from manufacturing example 5, pH 12.5, moisture content 2,000 ppm, average particle size: 4.9 μm (B-6): Calcium hydroxide from manufacturing example 6, pH 12.5, moisture content 5,000 ppm, average particle size: 3.0 μm (B-7): Calcium hydroxide from manufacturing example 7, pH 12.5, moisture content 10,000 ppm, average particle size: 4.0 μm (B'-1): Calcium carbonate, KS-1300 (manufactured by Calfine Co., Ltd., pH 9.0, moisture content 10,000 ppm, average particle size: 3.2 μm) (B'-2): Barium hydroxide (manufactured by Nippon Chemical Industrial Co., Ltd., pH 14.0, moisture content 9,000 ppm, average particle size: 5.0 μm) (B'-3): Calcium hydroxide, M-300 (manufactured by Inoue Mitsukichi Shoten, pH 12.5, water content 25,000 ppm, average particle size: 4.9 μm)

[0061] <Method for producing basic filler (B)> (Manufacturing example 1: Basic filler (B-1)) M-300 (calcium hydroxide, manufactured by Inoue Mitsuyoshi Shoten Co., Ltd.) was dried in a vacuum oven at a temperature of 100°C and a pressure of 300 Pa for 24 hours to produce a dried basic filler (B-1).

[0062] (Manufacturing example 2: Basic filler (B-2)) F-Lime-1300K (calcium oxide, manufactured by Calfine Co., Ltd.) was dried in a vacuum oven at a temperature of 100°C and a pressure of 300 Pa for 24 hours to produce a dried basic filler (B-2).

[0063] (Manufacturing Example 3: Basic Filler (B-3)) F-Lime-100 (calcium oxide, manufactured by Calfine Co., Ltd.) was dried in a vacuum oven at a temperature of 100°C and a pressure of 300 Pa for 24 hours to produce a dried basic filler (B-3).

[0064] (Manufacturing example 4: Basic filler (B-4)) Magnesium carbonate (Kinsei) (manufactured by Kamishima Chemical Industry Co., Ltd.) was dried in a vacuum oven at a temperature of 100°C and a pressure of 300 Pa for 24 hours to produce a dried basic filler (B-4).

[0065] (Manufacturing example 5: Basic filler (B-5)) Calcium carbonate (manufactured by Calfine Co., Ltd.) was dried in a vacuum oven at a temperature of 100°C and a pressure of 300 Pa for 24 hours to produce dried basic filler (B-5).

[0066] (Manufacturing example 6: Basic filler (B-6)) M-300 (calcium hydroxide, manufactured by Inoue Mitsuyoshi Shoten Co., Ltd.) was dried in a vacuum oven at a temperature of 80°C and a pressure of 300 Pa for 10 hours to produce a dried basic filler (B-6).

[0067] (Manufacturing example 7: Basic filler (B-7)) M-300 (calcium hydroxide, manufactured by Inoue Mitsuyoshi Shoten Co., Ltd.) was dried in a vacuum oven at a temperature of 80°C and a pressure of 300 Pa for 5 hours to produce a dried basic filler (B-7).

[0068] (Antioxidant (C)) (C-1): Chimassorb 944 (manufactured by BASF Japan Ltd., hindered amine antioxidant) poly[{6-[(1,1,3,3-tetramethylbutyl)amino]-S-triazine-2,4-diyl}{(2,2,6,6-tetramethyl-4-piperidyl)imino}-hexamethylene-{(2,2,6,6-tetramethyl-4-piperidyl)imino}]) (C-2): Irgastab FS 042 (manufactured by BASF Japan Ltd., hydroxylamine-based antioxidant) N,N-dioctadecylhydroxylamine (C-3): Irgafós38 (manufactured by BASF Japan Ltd., phosphorus-based antioxidant) bis(2,4-di-t-butyl-6-methylphenyl)ethyl phosphine (C-4): Phosphorus-based antioxidant of Production Example 8 (2,10-dimethyl-4,8-di-t-butyl-6-[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionyloxy]-12H-dibenzo[dg][1.3.2]dioxaphosphosine)

[0069] <Method for manufacturing antioxidant (C)> (Manufacturing Example 8: Manufacturing of antioxidant (C-4)) In a flask equipped with a thermometer, stirrer, and condenser, 10.2 parts of 2,2'-methylenebis(6-t-butyl-4-methylphenol) and 110 parts of toluene were added under a nitrogen stream. Then, 4.1 parts of phosphorus trichloride were added under stirring, followed by 6.7 parts of triethylamine, and the mixture was incubated at 80°C for 8 hours. After cooling to room temperature, 50 parts of toluene and 8.33 parts of 3-(3,5-di-t-butyl-4-hydroxyphenyl)propanol were added, followed by 3.3 parts of triethylamine, and the mixture was incubated at 80°C for 7 hours. After cooling to room temperature, the resulting triethylamine hydrochloride was filtered and washed. After concentrating the filtered liquid, the residue was purified by silica gel chromatography to obtain 4.6 parts of a white crystalline phosphorus-based antioxidant.

[0070] (Other antioxidants) (C'-1): ADEKA Stab AO-20 (manufactured by ADEKA Corporation, phenolic antioxidant) (C'-2): ADEKA Stab LA-24 (manufactured by ADEKA Corporation, benzotriazole antioxidant)

[0071] (Main resin (D)) (D-1): Novatec PP FA3EB(PP) (D-2): Suntech LD F1810 (LDPE) (D-3): Suntech HD J300 (HDPE) (D-4): Nipolon L F13 (L-LDPE)

[0072] (Example 1) [Manufacturing of masterbatch resin compositions for food packaging materials] A masterbatch resin composition (M-1) for food packaging was obtained by mixing polyolefin resin (A) at a ratio of 96.995% by mass, basic filler (B) at a ratio of 3% by mass, and antioxidant (C) at a ratio of 0.005% by mass, and extruding and granulating the mixture at 200°C using a twin-screw extruder (manufactured by Japan Steel Works, Ltd.). The antioxidant (C-1) content was 0.2 parts by mass per 100 parts by mass of basic filler (B-1).

[0073] (Examples 2-40, Comparative Examples 1-6) Pellet-shaped masterbatch resin compositions for food packaging materials (M-2 to 40, M-41 to 45) were produced in the same manner as in Example 1, except that the composition and blending ratio (mass%) were changed as shown in Table 1. In Comparative Example 6, M-46 had poor extrusion properties, making it impossible to produce a pellet-shaped masterbatch resin composition for food packaging materials. Therefore, film-forming properties, yellowness (YI value), number of film particles, and freshness retention performance were not evaluated.

[0074] (Example 41) [Manufacturing of thermoplastic resin compositions for food packaging materials] A mixture of polyolefin resin (A) (96.7% by mass of polyolefin resin (A-1), basic filler (B) (3% by mass of basic filler (B-1), and antioxidant (C) (0.3% by mass of antioxidant (C-3)) was prepared. The mixture was then extruded at 200°C using a twin-screw extruder (manufactured by Japan Steel Works, Ltd.) and granulated to obtain thermoplastic resin composition 1 (compound). The antioxidant (C-3) content was 10 parts by mass per 100 parts by mass of basic filler (B-1).

[0075] [Manufacturing of food packaging materials] The obtained thermoplastic resin composition (1) was used to produce a film-like food packaging material with a folded width of 450 mm and an average thickness of 50 μm using an inflation molding machine (manufactured by Hokushin Sangyo Co., Ltd.).

[0076] (Examples 42-44, Comparative Example 7) Thermoplastic resin compositions 2-4 and 48, which are compounds, were produced in the same manner as in Example 41, except that the composition and blending ratio (mass%) were changed as shown in Table 3. Subsequently, a film-like food packaging material was produced in the same manner as in Example 41. Furthermore, the thermoplastic resin composition 48 of Comparative Example 7 had poor film-forming properties and could not be used to produce a film-like food packaging material. Therefore, yellowness (YI value) evaluation, film piece count evaluation, and freshness preservation performance evaluation could not be performed.

[0077] (Example 45) The obtained masterbatch resin composition for food packaging materials (M-1) was placed in a super mixer (manufactured by Kawata Co., Ltd.) at a temperature of 20°C for 5 minutes, and then melt-kneaded in a twin-screw extruder (manufactured by Nippon Placon Co., Ltd.) set to a temperature of 200°C to obtain a pelletized thermoplastic resin composition 5 for food packaging materials.

[0078] [Manufacturing of food packaging materials] The obtained pelletized thermoplastic resin composition for food packaging was used to produce a film-like food packaging material with a folded width of 450 mm and an average thickness of 50 μm using an inflation molding machine (manufactured by Hokushin Sangyo Co., Ltd.).

[0079] (Examples 46-87, Comparative Examples 8-12) Pellet-shaped thermoplastic resin compositions 6-47 and 49-53 for food packaging materials were prepared in the same manner as in Example 45, except that the composition and blending ratio (mass%) were changed as shown in Table 3. Next, a film-like food packaging material was prepared in the same manner as in Example 45. Furthermore, the thermoplastic resin compositions 50, 51, and 53 for food packaging materials in Comparative Examples 9, 10, and 12 had poor film-forming properties and could not be used to produce film-like food packaging materials. Therefore, yellowness (YI value) evaluation, film piece count evaluation, and freshness preservation performance evaluation could not be performed.

[0080] [Table 1-1]

[0081] [Table 1-2]

[0082] [Table 1-3]

[0083] [Table 1-4]

[0084] [Table 2]

[0085] Evaluation of Masterbatch Resin Compositions, Thermoplastic Resin Compositions, and Food Packaging Materials The masterbatch resin composition, thermoplastic resin composition, and food packaging material of the present invention were evaluated using the following method. The results are shown in Table 3. The "extrusion processability" of the obtained masterbatch resin compositions or compounds was evaluated. Furthermore, the film-like food packaging materials molded using the obtained masterbatch resin compositions or compounds for food packaging were evaluated for "film-forming properties," "yellowness (YI value)," "number of film particles," and "freshness preservation performance." The results are shown in Table 3. The evaluation criteria were as follows, with ++++, +++, ++, and + being considered usable.

[0086] <Extrusion Processability Evaluation> The production of masterbatch resin compositions or compounds for food packaging materials, such as those shown in the examples, was carried out continuously for one hour using a twin-screw extruder. Strand breakage was checked during this process, and productivity (processability) was evaluated according to the following criteria. Strand breakage refers to the point at which the strand breaks and can no longer be drawn. +++: No strand breaks occur. ++: One or more but less than five strand breaks occurred. + : Strand breakage has occurred 5 or more times but less than 10 times. NG: More than 10 strand breaks occur, or pellets cannot be produced.

[0087] <Evaluation of film-forming properties> The film-forming properties of the obtained film-like food packaging material were evaluated as follows. The maximum take-up speed at which the balloon can be stably inflated while maintaining a fold width of 400 mm and an average thickness of 30 μm in the inflation film was measured, and the variation in fold width and the presence or absence of holes during measurement were checked. The width of the double film when the balloon-shaped molded film extruded from the die is folded into a double film by passing it through a cooling roll is called the fold width. A large variation in the fold width results in a large variation in thickness, making it difficult to maintain a cylindrical shape. In other words, it becomes difficult to stably form a balloon. Furthermore, holes in the manufactured film are considered defects and are evaluated as poor quality. Therefore, the film was perforated, the maximum take-up speed was set, and within the resulting film length of 20m, We evaluated the variation in folding width. [Evaluation Criteria] ++++: No holes are made in the film, the maximum take-up speed is 15m / min or more, and the variation in folding width is less than 10mm. +++: No holes are made in the film, the maximum take-up speed is 10m / min or more but less than 15m / min, and the variation in folding width is less than 20mm, or the maximum take-up speed is 15m / min or more, and the variation in folding width is 10mm or more but less than 20mm. ++: No holes were made in the film, but the maximum take-up speed was 10 m / min or more and the variation in folding width was 20 mm or more, or the maximum take-up speed was less than 10 m / min and the variation in folding width was less than 20 mm. +: No holes were made in the film, but the maximum take-up speed was less than 10m / min, and the fold width variation was 20mm or more. NG: A hole has formed in the film.

[0088] <Yellowness (YI value) evaluation> For the obtained film-like food packaging material, the L value (brightness), a value, and b value of the test piece were measured using a Kurabo AU Color COLOR7x image spectrophotometer with a D-65(10) standard light source. The YI value was calculated according to JIS K7373:2006 to measure the degree of yellowness. A smaller YI value indicates that yellowing has been suppressed. [Evaluation Criteria] ++++:0≦YI<3 +++ : 3 ≤ YI < 5 ++ : 5 ≤ YI < 10 + : 10 ≤ YI < 20 NG : 20 ≤ YI

[0089] <Film defect count evaluation> Regarding the obtained film - like food packaging material, visually observe the film surface, and directly compare and measure the size of the defects (visually compared with the "Miscellaneous Object Measurement Chart" manufactured by the Printing Bureau of the Ministry of Finance) and the number of defects of this size per 100 cm of the film. 2 Count and evaluate them. [Evaluation criteria] +++: No defects of size 0.03 mm 2 or larger. ++ : There are defects of size 0.03 mm 2 or larger, but no defects of size 0.05 mm 2 or larger. + : There are defects of size 0.05 mm 2 or larger, but no defects of size 0.1 mm 2 or larger. NG : There is 1 or more defect of size 0.1 mm 2 or larger.

[0090] <Freshness - retention performance evaluation> Put food into the obtained film - like food packaging material, seal it by heat - sealing, and then evaluate the freshness - retention performance based on the color value change and odor after leaving it for 3 days in an environment of 30°C and 85% RH. The detailed method is shown below.

[0091] First, cut a 1 - raceme (about 5 cm) of flower buds from commercially available cauliflower, and measure the L * value and b * value of the top of the flower bud using a colorimeter (Konica Minolta, Color Reader CR - 20). * Regarding the measurement of the L * value and b value, perform the measurement 3 times and use the average value of each. Next, for the L * value and b *The cauliflower whose values ​​were measured was placed inside food packaging. Next, the food packaging containing the sealed cauliflower was placed in a constant temperature and humidity chamber (ESPEC LHU124) set to 30°C and 85%RH, and left for 3 days. After that, the cauliflower was removed from the container and its color value was measured. The method for measuring the color value was the same as before the cauliflower was left to stand. Color L * value, b * For each value, the change in color value after leaving it unattended was calculated using the following formula. Color value change = (Color value after standing) - (Color value before standing)

[0092] The freshness preservation performance was evaluated based on changes in color values ​​according to the following criteria. [Evaluation Criteria] +++: Color L * value, b * The change in value is 3 or less for both. ++ : Color L * value, b * The change in value is greater than 3 and less than or equal to 5. + : Color L * value, b * If any one of the values ​​changes to a value greater than 5 NG: Color L * value, b * The change in value is greater than 5 for both. [Table 3]

[0093] As shown in Table 3, the masterbatch resin composition and thermoplastic resin composition for food packaging materials of the present invention exhibit excellent processability, and it was confirmed that food packaging materials formed from these masterbatch resin composition and thermoplastic resin composition exhibit excellent freshness preservation performance and appearance characteristics.

Claims

1. A masterbatch resin composition comprising a polyolefin resin (A), a basic filler (B), and an antioxidant (C), Basic filler (B) has a pH of 10.0 to 13.0 in water and a water content of 20,000 ppm or less. The antioxidant (C) is at least one selected from the group consisting of hindered amine antioxidants, hydroxylamine antioxidants, and phosphorus antioxidants. The content of antioxidant (C) is 0.1 to 450 parts by mass per 100 parts by mass of basic filler (B). The content of basic filler (B) is 3 to 50% by mass, based on 100% by mass of the masterbatch resin composition. Masterbatch resin composition for food packaging materials.

2. The masterbatch resin composition for food packaging materials according to claim 1, wherein the basic filler (B) is at least one selected from the group consisting of calcium oxide, calcium hydroxide, magnesium carbonate, and magnesium hydroxide.

3. The masterbatch resin composition for food packaging materials according to claim 1, wherein the average particle size of the basic filler (B) is 10.0 μm or less.

4. The masterbatch resin composition for food packaging materials according to claim 1, wherein the content of antioxidant (C) is 0.01 to 5% by mass based on 100% by mass of the masterbatch resin composition.

5. A thermoplastic resin composition for food packaging materials comprising the masterbatch resin composition for food packaging materials according to any one of claims 1 to 4, and a main resin (D).

6. The thermoplastic resin composition for food packaging materials according to claim 5, wherein the content of the basic filler (B) is 0.1 to 20% by mass, based on 100% by mass of the thermoplastic resin composition for food packaging materials.

7. A compound comprising a polyolefin resin (A), a basic filler (B), and an antioxidant (C), Basic filler (B) has a pH of 10.0 to 13.0 in water and a water content of 20,000 ppm or less. The antioxidant (C) is at least one selected from the group consisting of hindered amine antioxidants, hydroxylamine antioxidants, and phosphorus antioxidants. The content of antioxidant (C) is 0.1 to 450 parts by mass per 100 parts by mass of basic filler (B). The content of basic filler (B) is 0.1 to 20% by mass, based on 100% by mass of the compound. Compound for food packaging materials.

8. A food packaging material formed from the thermoplastic resin composition for food packaging materials described in claim 5 or the compound described in claim 7.

9. A method for producing a thermoplastic resin composition for food packaging materials, comprising the steps of melting and kneading a masterbatch resin composition for food packaging materials according to any one of claims 1 to 4, and a main resin (D).

Images