Resin composition and use thereof

Abstract

The present invention aims to obtain a resin composition which has good high-speed moldability, low adhesion to chill rolls, guide rolls, and the like during film molding, and excellent adhesion to resins having polar groups (polar resins), and relates to a resin composition containing 75 to 100 parts by mass of a propylene-based polymer (A) of which at least a part is modified with a polar compound, and 0 to 25 parts by mass of a copolymer (B) of ethylene and at least one α-olefin selected from α-olefins having 3 to 20 carbon atoms, which satisfies prescribed conditions (wherein the total of (A) and (B) is 100 parts by mass), and which satisfies prescribed conditions.

Description

Technical Field

[0001] Polyolefin resins such as polyethylene and polypropylene are widely used as constituent materials for various food packaging materials due to their excellent moldability, hygiene, water vapor barrier properties, and low price.

[0002] Polyolefin resins are highly permeable, so they are often laminated with polar resins such as ethylene-vinyl alcohol copolymer (EVOH), polyamide (PA), and polyester (e.g., polyethylene terephthalate (PET)) to maintain the freshness of the contents and extend the shelf life, and are used as food packaging materials.

[0003] Because polyolefin resins have poor adhesion to polar resins, grafted polyethylene, polypropylene, etc., are used as adhesive layers, or polyolefin resins containing grafted polyethylene, polypropylene, etc., are used as polyolefin resins.

[0004] Food packaging materials made from this type of laminate can be manufactured by melt (co)extrusion molding, such as casting, blow molding, and extrusion coating. Furthermore, although research has been conducted on increasing the speed of molding processes to improve the productivity of food packaging materials, there are instances where the productivity of multi-layer laminates cannot be improved because some of the materials constituting the laminate cannot support high-speed molding.

[0005] To address the aforementioned issues, for example, Patent Document 1 discloses a technique for improving the molding stability of polypropylene films by blending high melt tension polypropylene resins into polypropylene resins. However, this description relates to the stability of the melt film during blow molding and does not mention high-speed molding performance.

[0006] Although patent documents 2 and 3 disclose adhesive resin compositions capable of high-speed lamination, since they are highly adhesive resin compositions containing soft propylene polymers, when co-extruded with polypropylene, EVOH, etc., a "back-winding phenomenon" occurs where the adhesive resin composition wraps around the ends of the film, resulting in adhesion to cooling rollers, guide rollers, etc., and the molding speed cannot be increased.

[0007] Existing technical documents

[0008] Patent documents

[0009] Patent Document 1: Japanese Patent Application Publication No. 2003-64193

[0010] Patent Document 2: Japanese Patent No. 5915253

[0011] Patent Document 3: Japanese Patent Application Publication No. 2018-135488 Summary of the Invention

[0012] The problem that the invention aims to solve

[0013] The object of the present invention is to obtain a resin composition with good high-speed formability, low adhesion to cooling rollers, guide rollers, etc. during film forming, and excellent adhesion to resins (polar resins) with polar groups such as ethylene-vinyl alcohol copolymer (EVOH), polyamide (PA), and polyester, as well as a laminate suitable for food packaging films containing the resin composition.

[0014] Technical solutions for solving the problem

[0015] This invention relates to a resin composition, characterized in that it contains: 75 to 100 parts by weight of a propylene polymer (A); and 0 to 25 parts by weight of a copolymer (B) of ethylene and at least one α-olefin selected from α-olefins having 3 to 20 carbon atoms, satisfying conditions (b-1) and (b-2), wherein the total of (A) and (B) is 100 parts by weight.

[0016] At least a portion of the propylene polymer (A) is modified by a polar compound, and the resin composition satisfies the following conditions (1) to (3).

[0017] (b-1) The content of structural units derived from ethylene is 50-99 mol%, and the content of structural units derived from α-olefins with 3-20 carbon atoms is 1-50 mol%, wherein the total content of structural units derived from ethylene and structural units derived from α-olefins is 100 mol%.

[0018] (b-2) The melt flow rate (MFR, 190°C, 2.16 kg load) measured according to ASTM D1238 is in the range of 0.1 to 50 g / 10 min.

[0019] (1) The melt flow rate (MFR) measured at a temperature of 230℃ and a load of 2.16kg was in the range of 1 to 100 g / 10 min.

[0020] (2) Density is between 0.89 and 0.93 g / cm³ 3 Within the range,

[0021] (3) The melt tension measured at 230℃ is below 10.0mN.

[0022] Invention Effects

[0023] The resin composition of the present invention has the characteristics of good high-speed molding performance, low adhesion to cooling rollers, guide rollers, etc. during film molding, and excellent adhesion to resins (polar resins) with polar groups such as ethylene-vinyl alcohol copolymer (EVOH), polyamide (PA), and polyester (e.g., polyethylene terephthalate (PET)). Detailed Implementation

[0024] The resin composition of the present invention is a composition containing a propylene polymer (A) and an ethylene-α-olefin copolymer (B) (hereinafter also referred to as "ethylene-α-olefin copolymer (B)").

[0025] <Propylene Polymer (A)>

[0026] The propylene polymer (A), which is one of the components constituting the resin composition of the present invention, can satisfy the following conditions (1) to (4).

[0027] <Condition(1)>

[0028] The melt flow rate (MFR) measured at a temperature of 230°C and a load of 2.16 kg is in the range of 1 to 100 g / 10 min, preferably 1 to 50 g / 10 min, and more preferably 1 to 30 g / 10 min.

[0029] By ensuring that the MFR of the propylene polymer (A) meets the above range, it is possible to obtain molded articles with good extrudability and excellent surface appearance.

[0030] <Condition (2)>

[0031] Density ranges from 0.89 to 0.93 g / cm³ 3 The preferred value is 0.89–0.92 g / cm³. 3 More preferably, it is 0.90–0.92 g / cm³. 3 The range.

[0032] By ensuring that the density of the propylene polymer (A) meets the above-mentioned range, it exhibits low adhesion to cooling rollers, guide rollers, etc., during film forming and excellent forming stability.

[0033] <Condition (3)>

[0034] The melt tension measured at 230°C is in the range of 10 mN or less, preferably 9.5 mN or less.

[0035] When the melt tension of the propylene polymer (A) is below 10 mN, the melt curtain after melt extrusion is not prone to surge when the film stretching speed increases, resulting in excellent high-speed molding performance.

[0036] <Condition (4)>

[0037] At least a portion of the propylene polymer (A) of the present invention is modified by a polar compound, preferably by an unsaturated carboxylic acid or its derivative (preferably by graft modification).

[0038] In this invention, "at least a portion modified by a polar compound" refers to two cases: a mixture (composition) of an unmodified propylene polymer and a propylene polymer modified by a polar compound, and the entire propylene polymer (A) being modified by a polar compound. "At least a portion" indicates that it is not necessary for the entire propylene polymer (A) of this invention to be modified by a polar compound.

[0039] The amount of polar compound modification (grafting amount of polar compound) in the propylene polymer (A) of the present invention is in the range of 0.01 to 10% by mass, more preferably 0.02 to 5% by mass, and even more preferably 0.04 to 1% by mass.

[0040] The propylene polymer (A) of the present invention can be either a propylene polymer (A) entirely modified by a polar compound, or a mixture (composition) of a propylene polymer modified by a polar compound and an unmodified propylene polymer. In the case of a mixture, the amount of polar compound modification in the mixture needs to meet the above-mentioned range.

[0041] When the propylene polymer (A) of the present invention is a mixture of a propylene polymer modified by a polar compound and an unmodified propylene polymer, the mixture preferably satisfies the above conditions (1) to (3), and more preferably satisfies the following conditions (5) to (7). The propylene polymer modified by a polar compound or the unmodified propylene polymer does not necessarily need to satisfy all of the above conditions (1) to (3) and the following conditions (5) to (7).

[0042] Furthermore, when the propylene polymer (A) of the present invention is a mixture of a propylene polymer modified by a polar compound and an unmodified propylene polymer, the amount of the propylene polymer modified by the polar compound and the unmodified propylene polymer are not particularly limited, and can be appropriately determined according to the amount of modification of the propylene polymer modified by the polar compound.

[0043] By modifying the propylene polymer (A) of the present invention to meet the above-mentioned range, a resin composition with excellent adhesion to polar resins such as ethylene-vinyl alcohol copolymer (EVOH), polyamide (PA), and polyester can be obtained, thereby obtaining a molded body with low content of foreign matter such as fish eyes and black spots during melt extrusion molding.

[0044] As a method for achieving the above-mentioned modification amount of the propylene polymer (A) of the present invention, a method of modifying the propylene polymer with a polar compound to achieve the above-mentioned modification amount can be adopted, or a method of mixing the propylene polymer obtained by increasing the modification amount with an unmodified propylene polymer in advance and adjusting the modification amount to the above-mentioned range to obtain the propylene polymer (A) can be adopted.

[0045] As a method for modifying the propylene polymer of the present invention, various known methods can be used. For example, the propylene polymer can be dissolved in an organic solvent, and then a polar compound such as an unsaturated carboxylic acid or its derivative, as well as a free radical initiator such as an organic peroxide as needed, can be added to the resulting solution. The reaction can be carried out at a temperature of 60 to 350°C, preferably 80 to 190°C, for 0.5 to 15 hours, preferably 1 to 10 hours. Alternatively, the propylene polymer, unsaturated carboxylic acid or its derivative, and a free radical initiator such as an organic peroxide as needed can be added in a solvent-free environment using an extruder or the like, and the reaction can be carried out at a temperature of 160 to 350°C, preferably above the melting point of the propylene polymer, for 0.5 to 10 minutes.

[0046] The grafting modification amount of the propylene polymer (A) was determined by infrared absorption analysis using the peaks of structural units from polar compounds such as unsaturated carboxylic acids or their derivatives (1790 cm⁻¹ when using maleic anhydride). ﹣1 The strength of the grafting modification was determined by quantifying the amount of grafting modification from the above structural units using a pre-plotted calibration curve.

[0047] The propylene polymer (A) of the present invention preferably satisfies the following condition (5).

[0048] <Condition (5)>

[0049] The propylene polymer (A) of the present invention preferably has a melt tension of 7 mN or less, more preferably 6.9 mN or less, and even more preferably 6.8 mN or less, as measured at a temperature of 250°C.

[0050] Propylene polymers (A) whose melt tension measured at 250°C meets the above range are less prone to melt curtain surges after melt extrusion and have excellent high-speed molding properties when the film stretching speed increases.

[0051] The melt tension of the propylene polymer (A) of the present invention was measured by the following method.

[0052] Using a Capilograph 1D (9.55mm barrel diameter, 250mm effective barrel length) manufactured by Toyo Seiki Co., Ltd., and an orifice with a nozzle diameter of 2.095mm and a length of 8.0mm, a propylene polymer (A) was melt-extruded at set temperatures of 230℃ and 250℃ and a piston movement speed of 15m / min. The melt-extruded material was stretched for a certain time at a stretching speed of 15m / min, and the average melt tension during the measurement time was taken as the melt tension (mN).

[0053] The propylene polymer (A) of the present invention preferably satisfies the following condition (6).

[0054] <Condition (6)>

[0055] The propylene polymer (A) of the present invention preferably has a crystallization peak measured by differential scanning calorimetry (DSC) in the range of 120-135°C, more preferably 120-132°C, and even more preferably 120-130°C.

[0056] Propylene polymers (A) with crystallization peaks within the above range exhibit excellent molding stability and easy solidification of the melt curtain after melt extrusion during film forming.

[0057] The propylene polymer (A) of the present invention preferably satisfies the following condition (7).

[0058] <Condition (7)>

[0059] The difference between the crystallization peak and the melting peak of the propylene polymer (A) of the present invention, measured by differential scanning calorimetry (DSC), is preferably 35°C or more, more preferably 36°C or more, and even more preferably 37°C or more.

[0060] Propylene polymers (A) with a difference between the crystallization peak and the melting peak within the above range exhibit excellent adhesion to polar resins such as ethylene-vinyl alcohol copolymer (EVOH), polyamide (PA), and polyester.

[0061] The method for determining the crystallization temperature (crystallization peak) and melting point (melting peak) of the propylene polymer (A) of the present invention will be described later.

[0062] Examples of the propylene-based polymer (A) of the present invention include propylene homopolymers, or copolymers of propylene with at least one α-olefin having 2 to 20 carbon atoms other than propylene. In the present invention, examples of α-olefins having 2 to 20 carbon atoms other than propylene include ethylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicosene, etc., preferably ethylene or α-olefins having 4 to 10 carbon atoms.

[0063] The copolymers of propylene with these α-olefins can be random copolymers or block copolymers. The structural units derived from these α-olefins are present in the copolymers of α-olefins and propylene at a concentration of 35 mol% or less, preferably 30 mol% or less.

[0064] It should be noted that the propylene polymer (A) of the present invention is not limited to one type, but may be a mixture (composition) of two or more types. When the propylene polymer (A) of the present invention is a composition of two or more types, the composition preferably satisfies the above conditions.

[0065] The method for manufacturing the propylene polymer (A) of the present invention is not particularly limited, and known methods using known catalysts such as Ziegler-Natta catalysts and metallocene catalysts can be cited.

[0066] The propylene polymer (A) of the present invention can be any structure of isotactic or syndiotactic, and any structure can be selected with consideration of compatibility with the ethylene-α-olefin copolymer (B) described later.

[0067] <Ethylene-α-olefin copolymer (B)>

[0068] The ethylene-α-olefin copolymer (B), which is another component constituting the resin composition of the present invention, is a copolymer of ethylene and at least one α-olefin selected from α-olefins having 3 to 20 carbon atoms, satisfying the following conditions (b-1) and (b-2).

[0069] <Condition (b-1)>

[0070] The content of the structural units derived from ethylene is in the range of 50-99 mol%, preferably 70-95 mol%, more preferably 75-90 mol%, and the content of the structural units derived from α-olefins with 3-20 carbon atoms is in the range of 1-50 mol%, preferably 5-30 mol%, more preferably 10-25 mol%, wherein the total content of the structural units derived from ethylene and the content of the structural units derived from α-olefins is 100 mol%.

[0071] By ensuring that the content of structural units derived from ethylene meets the above-mentioned range, the resin composition containing the ethylene-α-olefin copolymer (B) exhibits good high-speed molding properties and low adhesion to cooling rollers, guide rollers, etc. during film molding.

[0072] <Condition (b-2)>

[0073] The melt flow rate (MFR: 190°C, 2.16 kg load) measured according to ASTM D1238 is in the range of 0.1 to 50 g / 10 min, preferably 0.1 to 35 g / 10 min, and more preferably 1 to 35 g / 10 min.

[0074] There are no particular limitations on the method for manufacturing the ethylene-α-olefin copolymer (B) of the present invention, and known methods using known catalysts such as Ziegler-Natta catalysts and metallocene catalysts can be cited.

[0075] Composition of propylene-based polymers (A) and ethylene-α-olefin copolymers (B)

[0076] The quantitative determination of the content ratio of α-olefin-derived structural units and propylene-derived structural units in propylene-based polymer (A), and the quantitative determination of the content ratio of α-olefin-derived structural units and ethylene-derived structural units in ethylene-α-olefin copolymer (B) were performed using... 13 C-NMR was performed under the following apparatus and conditions.

[0077] A JECX400P nuclear magnetic resonance (NMR) instrument manufactured by NJE Ltd was used under the following conditions: a mixed solvent of deuterated o-dichlorobenzene / deuterated benzene (80 / 20 volume %) was used as the solvent; the sample concentration was 60 mg / 0.6 mL; the measurement temperature was 120 °C; and the observed nuclei were... 13 C(100MHz), the sequence is a single-pulse proton decoupling, the pulse width is 4.62μs (45° pulse), the repetition time is 5.5 seconds, the cumulative number of times is 8000, and the chemical shift reference value is 29.73ppm.

[0078] <Resin Composition>

[0079] The resin composition of the present invention is a resin composition containing 75 to 100 parts by weight of the above-mentioned propylene polymer (A), preferably 80 to 100 parts by weight, more preferably 90 to 100 parts by weight; and 0 to 25 parts by weight of the above-mentioned ethylene-α-olefin copolymer (B), preferably 0 to 20 parts by weight, more preferably 0 to 10 parts by weight, wherein the total of (A) and (B) is 100 parts by weight.

[0080] When the propylene polymer (A) contained in the resin composition of the present invention is a mixture of a propylene polymer modified by a polar compound and an unmodified propylene polymer, the amount of the propylene polymer modified by the polar compound in the propylene polymer (A) is generally in the range of 1 to 25 parts by mass or 1 to 25% by mass, preferably 2 to 20 parts by mass or 2 to 20% by mass, and more preferably 3 to 15 parts by mass or 3 to 15% by mass.

[0081] Furthermore, the resin composition of the present invention satisfies the following conditions (1) to (3).

[0082] <Condition(1)>

[0083] The melt flow rate (MFR) measured at a temperature of 230°C and a load of 2.16 kg is in the range of 1 to 100 g / 10 min, preferably 1 to 50 g / 10 min, and more preferably 1 to 30 g / 10 min.

[0084] By ensuring that the MFR of the resin composition meets the above-mentioned range, it is possible to obtain molded articles with good extrudability and excellent surface appearance.

[0085] <Condition (2)>

[0086] Density ranges from 0.89 to 0.93 g / cm³ 3 The preferred value is 0.89–0.92 g / cm³. 3 More preferably, it is 0.90–0.92 g / cm³. 3 The range.

[0087] By ensuring that the density of the resin composition meets the above-mentioned range, a resin composition with low adhesion to cooling rollers, guide rollers, etc., and excellent molding stability can be obtained during film molding.

[0088] <Condition (3)>

[0089] The melt tension measured at 230°C is in the range of 10 mN or less or 10.0 Mn or less, preferably 9.5 mN or less, and more preferably 9.1 mN or less.

[0090] By ensuring that the melt tension of the resin composition meets the above-mentioned range, a resin composition that is less prone to melt extrusion surging during film molding and exhibits excellent high-speed molding performance can be obtained.

[0091] The melt tension of the resin composition measured at 230°C can be controlled by changing the proportion of the propylene polymer (A) which tends to have relatively low melt tension and the ethylene-α-olefin copolymer (B) which tends to have relatively high melt tension, or by changing the proportion of each propylene polymer when there are two or more propylene polymers (A), or by changing whether the nucleating agent is added, the amount added, and the type of nucleating agent.

[0092] The resin composition of the present invention preferably satisfies the following condition (4).

[0093] <Condition (4)>

[0094] The resin composition of the present invention preferably has a melt tension of 7 mN or less or 7.0 mN or less, more preferably 6.9 mN or less, and even more preferably 6.8 mN or less, as measured at a temperature of 250°C.

[0095] When a resin composition with a melt tension within the above range, measured at 250°C, is molded into a film, the melt curtain after melt extrusion is less prone to surging, resulting in excellent high-speed molding performance.

[0096] The melt tension of the resin composition measured at 250°C can be controlled using the same method as the melt tension of the resin composition measured at 230°C.

[0097] It should be noted that the method for measuring the melt tension of the resin composition of the present invention is the same as that for measuring the melt tension of the propylene polymer (A) described above.

[0098] The resin composition of the present invention preferably satisfies the following condition (5).

[0099] <Condition (5)>

[0100] The crystallization peak of the resin composition of the present invention, measured by differential scanning calorimetry (DSC) from the propylene polymer (A), is preferably in the range of 120-135°C, more preferably 120-132°C, and even more preferably 120-130°C.

[0101] Resin compositions with crystallization peaks within the above range exhibit excellent molding stability and easy curing of the melt curtain after melt extrusion during film forming.

[0102] The resin composition of the present invention preferably satisfies the following condition (6).

[0103] <Condition (6)>

[0104] The difference between the crystallization peak and the melting peak of the propylene polymer (A) represented by the following formula, as measured by differential scanning calorimetry (DSC) of the resin composition of the present invention, is preferably 35°C or more, more preferably 36°C or more, and even more preferably 37°C or more.

[0105] [Melting peak (°C) from propylene polymer (A)] - [Crystallization peak (°C) from propylene polymer (A)]

[0106] Resin compositions with a difference between the crystallization peak and the melting peak within the above-mentioned range exhibit excellent adhesion to polar resins such as ethylene-vinyl alcohol copolymer (EVOH), polyamide (PA), and polyester.

[0107] It should be noted that the crystallization temperature (crystallization peak) and melting point (melting peak) of the resin composition of the present invention are determined by the same method as those for determining the crystallization temperature (crystallization peak) and melting point (melting peak) of the propylene polymer (A) described above.

[0108] The resin composition of the present invention preferably contains a nucleating agent in addition to the above-mentioned propylene polymer (A) and ethylene-α-olefin copolymer (B).

[0109] Examples of crystallizing nucleating agents that can be added to the resin composition of the present invention include, for example, sodium benzoate, dibenzyl sorbitol, bis(p-methylbenzyl)sorbitol, bis(p-ethylbenzyl)sorbitol, sodium 2,2-methylenebis(4,6-di-tert-butylphenyl)phosphite, talc, titanium dioxide, aluminum di-p-tert-butylbenzoate, aromatic phosphate salts, aromatic carboxylic acids, nonitol-based nucleating agents such as 7,8,9-trideoxy-3,5:4,6-bis-O-[(4-propylphenyl)methylene]-D-glycerol-L-gulose-nonitol, and rosin-based nucleating agents. These can be used alone or in combination of two or more.

[0110] When the resin composition of the present invention contains a crystallizing nucleating agent, the amount is 0.4 parts by mass or less relative to 100 parts by mass of the above-mentioned propylene polymer (A) and ethylene-α-olefin copolymer (B).

[0111] Resin compositions containing nucleating agents exhibit rapid curing of the melt curtain after melt extrusion and excellent high-speed molding properties. Furthermore, molded articles with excellent transparency can be obtained. Moreover, resin compositions containing nucleating agents tend to have lower melt tension compared to resin compositions without nucleating agents.

[0112] In addition to the above-mentioned nucleating agents, the resin composition of the present invention may, as needed, contain antioxidants, ultraviolet absorbers, neutralizers, light stabilizers, antistatic agents, antiblocking agents, lubricants, odor absorbers, antibacterial agents, pigments, inorganic and organic fillers, and various synthetic resins, provided that it does not impair the purpose of the present invention.

[0113] The resin composition of the present invention can be used alone by known thermoforming methods such as calendering, extrusion, injection molding, blow molding, blow molding, extrusion blow molding, injection blow molding, compression molding, vacuum forming, and foaming molding for, for example, sheets, films, hollow molded bodies, etc.

[0114] Furthermore, the resin composition of the present invention can also be laminated (bonded) with a substrate to form a laminate.

[0115] <Substrate>

[0116] The substrate that can be laminated with the resin composition of the present invention is not particularly limited, as long as it is an article that can be used as a laminate, such as a sheet, film, tray, or container. Examples of substrates include films formed of polyesters such as polyethylene terephthalate and polyethylene naphthalate, polycarbonate films, polyamide films made of nylon 6, nylon 66, etc., ethylene-vinyl alcohol copolymer films, polyvinyl alcohol films, polyvinyl chloride films, polyvinylidene chloride films, etc., thermoplastic resin films, or sheets made of these thermoplastic resins, as well as tray-shaped or cup-shaped containers obtained by thermoforming the sheets, and such shapes as aluminum foil, paper, etc.

[0117] In addition, thermoplastic resin films can be unstretched films or uniaxial or biaxial stretched films.

[0118] When the substrate is a thermoplastic resin, the laminate can be obtained by various known methods, such as co-extruding the resin composition of the present invention with a thermoplastic resin to form a laminate, extruding and coating (extrusion lamination) the resin composition of the present invention onto a pre-prepared thermoplastic resin film or sheet to form a laminate, or laminating a pre-prepared thermoplastic resin film or sheet with a resin composition film or sheet of the present invention (dry lamination) to form a laminate. Among the methods for obtaining the laminate, the method of co-extruding the resin composition of the present invention with a thermoplastic resin to form a laminate is preferred.

[0119] "use"

[0120] Laminates containing the resin composition of the present invention can be used for various known applications, such as food packaging films, cups, bottles, plates, tubes, BIB (box-in-box) and other food containers, as well as in both food and non-food applications. Furthermore, when films made of polyesters such as polyethylene terephthalate and polyethylene naphthalate, polycarbonate films, polyamide films made of nylon 6 and nylon 66, ethylene-vinyl alcohol copolymer films, and polyvinyl alcohol films are used as the substrate, excellent gas barrier properties are also observed.

[0121] (Packaging materials)

[0122] Laminated bodies containing the resin compositions of the present invention can also be used as packaging materials. As packaging materials, they are suitable for use as materials for food and beverage, cosmetic, grocery, and other packaging containers and bags, as well as food packaging, filler packaging, fiber packaging, etc.

[0123] Packaging containers and bags can be obtained by forming film or sheet laminates into the desired shape through vacuum forming or pressure forming, or by forming laminates into the desired shape of packaging containers and bags.

[0124] Packaging containers and bags containing contents can be obtained, for example, by filling the containers and bags with the contents, then covering them with a known film as a lid, and finally heat-sealing the top and sides of the containers. These containers and bags are suitable for use as packaging for instant noodles, sauces, jellies, puddings, snacks, etc.

[0125] Example

[0126] The invention is described in more detail below with reference to embodiments, but the invention is not limited to these embodiments in any way.

[0127] The propylene polymer (A) and ethylene α-olefin copolymer (B) used in the examples and comparative examples are shown below. It should be noted that, unless otherwise stated, these polyolefins were polymerized using conventional methods.

[0128] (1) Propylene polymers (A)

[0129] The propylene polymers (A) used in the examples and comparative examples are a suitable mixture of the following PP-1, PP-2 and modified PP.

[0130] (1-1)PP-1: Homopolymer of polypropylene (propylene homopolymer)

[0131] MFR = 7g / 10 minutes, density 0.90g / cm³ 3 .

[0132] (1-2)PP-2: Homopolymer of polypropylene (propylene homopolymer)

[0133] MFR = 3g / 10 minutes, density 0.90g / cm³ 3 .

[0134] (1-3) Modified PP: Maleic anhydride modified homopolymer polypropylene

[0135] MFR = 100g / 10min, density 0.90g / cm³ 3 The grafting amount of maleic anhydride was 1.0% by mass.

[0136] (2) Ethylene-α-olefin copolymer (B)

[0137] (2-1)EBR: Ethylene-1-butene copolymer

[0138] MFR = 4g / 10 minutes, density 0.89g / cm³ 3 Ethylene content = 88 mol%, 1-butene content = 12 mol%.

[0139] As a crystal nucleating agent, Milliken's product name, Millad NX8000 (noniol-based crystal nucleating agent), was used.

[0140] [Conditions for determining physical properties]

[0141] Melt Flow Rate (MFR)

[0142] MFR was determined according to ASTM D 1238 for propylene polymers at 230°C and 2.16 kg load, and for ethylene polymers at 190°C and 2.16 kg load.

[0143] <Density>

[0144] Density was determined according to JIS K7112 (density gradient tube method).

[0145] Composition of ethylene-α-olefin copolymers

[0146] The content ratio of α-olefin-derived structural units and ethylene-derived structural units in ethylene-α-olefin copolymers is determined by... 13 C-NMR was used for quantification under the following apparatus and conditions.

[0147] A JECX400P nuclear magnetic resonance (NMR) instrument manufactured by NJE Ltd was used under the following conditions: a mixed solvent of deuterated o-dichlorobenzene / deuterated benzene (80 / 20 volume %) was used as the solvent; the sample concentration was 60 mg / 0.6 mL; the measurement temperature was 120 °C; and the observed nuclei were... 13 C(100MHz), the sequence is a single-pulse proton decoupling, the pulse width is 4.62μs (45° pulse), the repetition time is 5.5 seconds, the cumulative number of times is 8000, and the chemical shift reference value is 29.73ppm.

[0148] <Crystallization temperature and melting point>

[0149] The crystallization temperature and melting point were determined using differential scanning calorimetry (DSC) as follows. Approximately 5 mg of sample was sealed in an aluminum dish and heated from room temperature to 230 °C at a rate of 10 °C / min. To ensure complete melting, the sample was held at 230 °C for 10 minutes. It was then cooled to -20 °C at a rate of 10 °C / min, and after being placed at -20 °C for 10 minutes, the sample was again heated from room temperature to 230 °C at a rate of 10 °C / min. The peak temperature detected during the cooling test was taken as the crystallization temperature (Tc), and the peak temperature from the second heating test was taken as the melting point (Tm).

[0150] <Grafting Modification Quantity>

[0151] The characteristic peaks of structural units from unsaturated carboxylic acids and / or their derivatives were determined by infrared absorption analysis (1790 cm⁻¹ when using maleic anhydride). ﹣1The strength of the above structural unit (graft modification amount) was quantified using a pre-plotted calibration curve.

[0152] <Membrane Formability>

[0153] Using an extrusion molding machine (film forming machine) with an attached T-die, and employing a screw with a diameter of 40 mm and an effective length L / D = 26, the resin compositions obtained in the examples and comparative examples as described below were extruded at a temperature of 240°C. The mixtures were then stretched using cooling rollers set to 25°C to form a single-layer 40 μm film. The film was formed into a single layer at stretching speeds of 5 m / min, 10 m / min, and 20 m / min, and its formability was determined according to the following two criteria.

[0154] The surge of molten resin film after T-die extrusion

[0155] Formability ○: No surging occurred in the width direction of the film.

[0156] Formability △: Slight surging in the width direction of the film

[0157] Formability ×: Surge occurred in the width direction of the film.

[0158] Adhesion to cooling rollers

[0159] Formability ○: No peeling marks appeared on the film surface when passing through the cooling rollers.

[0160] Formability △: Slight peeling marks appeared on the film surface when passing through the cooling rollers.

[0161] Formability ×: Obvious peeling marks appeared on the film surface when passing through the cooling rollers.

[0162] <Preparation of Laminated Structures>

[0163] Using a molding apparatus (multilayer film molding apparatus) equipped with three three-layer T-dies, laminates (laminated films) were prepared by co-extrusion molding of ethylene-vinyl alcohol copolymer (Kuraray EVAL F101A, MFR (190°C, 2.16 kg) = 1.6 g / 10 min), the resin composition obtained in the examples and comparative examples, and polypropylene (Prime Polypro F327, MFR = 7). The ethylene-vinyl alcohol copolymer was extruded using a screw with a diameter of 40 mm and an effective length L / D = 26 at 220°C; the resin composition was extruded using a screw with a diameter of 40 mm and an effective length L / D = 26 at 240°C; and the polypropylene was extruded using a screw with a diameter of 50 mm and an effective length L / D = 28 at 240°C. The T-die temperature was set to 220°C. By appropriately adjusting the screw speed and drawing speed of 5 m / min, a laminate of ethylene-vinyl alcohol copolymer / resin composition / polypropylene = 40 / 40 / 160 μm is prepared.

[0164] <Adhesion strength of laminates>

[0165] The bond strength (in N / 15 mm) of the obtained laminate was determined using a tensile testing machine and the T-peel method at room temperature (23°C). The crosshead speed was set to 300 mm / min.

[0166] [Example 1]

[0167] As a propylene polymer (A), the above-mentioned PP-1 (60 parts by mass), the above-mentioned PP-2 (36 parts by mass), and modified PP (4 parts by mass) were melt-blended using a single screw extruder at a temperature of 230°C to obtain resin composition 1.

[0168] It should be noted that the amount of graft modification of the propylene polymer (A) in resin composition 1 is 0.04% by mass.

[0169] [Examples 2-5 and Comparative Examples 1-3]

[0170] In Examples 2-5 and Comparative Examples 1-3, resin compositions were prepared according to the formulations shown in Tables 1-2, using the same method as in Example 1.

[0171] The composition obtained in Example 2 is resin composition 2, and the amount of graft modification of propylene polymer (A) in resin composition 2 is 0.08 by mass.

[0172] The composition obtained in Example 3 is resin composition 3, and the amount of graft modification of propylene polymer (A) in resin composition 3 is 0.04 by mass.

[0173] The composition obtained in Example 4 is resin composition 4, and the amount of graft modification of propylene polymer (A) in resin composition 4 is 0.04 by mass.

[0174] The composition obtained in Example 5 is resin composition 5, and the amount of graft modification of propylene polymer (A) in resin composition 5 is 0.09 by mass.

[0175] The composition obtained in Comparative Example 1 is resin composition 6, and the amount of graft modification of propylene polymer (A) in resin composition 6 is 0.04 by mass.

[0176] The composition obtained in Comparative Example 2 is resin composition 7, and the amount of graft modification of propylene polymer (A) in resin composition 7 is 0.04 by mass.

[0177] The composition obtained in Comparative Example 3 was resin composition 8, and the amount of graft modification of the propylene polymer (A) in resin composition 8 was 0.04 by mass.

[0178] The MFR, density, melting point and crystallization temperature of the resin compositions obtained in the examples and comparative examples, the formability evaluation results of the single-layer film of the resin composition, and the adhesive strength evaluation results of the laminate obtained from the resin composition are shown in Tables 1 to 2.

[0179] [Table 1]

[0180]

[0181] [Table 2]

[0182]

Claims

1. A resin composition, characterized in that, contain: A copolymer of propylene polymer (A) in the form of 75-100 parts by weight and α-olefin (B) in the form of 0-25 parts by weight, wherein the total of (A) and (B) is 100 parts by weight, and a nucleating agent. The copolymer of the α-olefin (B) is a copolymer of ethylene and at least one selected from α-olefins having 3 to 20 carbon atoms, satisfying the following conditions (b-1) and (b-2). The content of the nucleating agent is less than 0.4 parts by weight and not less than 0 parts by weight relative to 100 parts by weight of the total mass of the propylene polymer (A) and the ethylene-α-olefin copolymer (B). At least a portion of the propylene polymer (A) is modified with a polar compound, and the resin composition satisfies the following conditions (1) to (3): (b-1) The content of structural units derived from ethylene is 50–99 mol%, and the content of structural units derived from α-olefins with 3–20 carbon atoms is 1–50 mol%, wherein the total content of structural units derived from ethylene and structural units derived from α-olefins is 100 mol%. (b-2) The melt flow rate, measured according to ASTM D1238 at a temperature of 190°C and a load of 2.16 kg, is in the range of 0.1 to 50 g / 10 min; (1) The melt flow rate (MFR) measured at a temperature of 230℃ and a load of 2.16kg was in the range of 1 to 30 g / 10 min; (2) Density is between 0.89 and 0.93 g / cm³ 3 Within the range; (3) The melt tension measured at 230°C by the following method is above 8.0 mN and below 10.0 mN; Measurement method: Using a nozzle with a diameter of 2.095 mm and a length of 8.0 mm, melt extrusion was carried out at a set temperature of 230℃ and a piston moving speed of 15 m / min. The extruded material was stretched for a certain time at a stretching speed of 15 m / min. The average melt tension during the measurement time was taken as the melt tension, and the unit was mN.

2. The resin composition according to claim 1, characterized in that: The resin composition contains 90 to 100 parts by weight of a propylene polymer (A) and 0 to 10 parts by weight of a copolymer (B), wherein the total of (A) and (B) is 100 parts by weight.

3. The resin composition according to claim 1 or 2, characterized in that: The amount of propylene polymer (A) modified by polar compounds is in the range of 1 to 25% by mass.

4. The resin composition according to claim 1 or 2, characterized in that: The polar compounds used to modify the propylene polymer (A) are unsaturated carboxylic acids or their derivatives.

5. The resin composition according to claim 1 or 2, characterized in that: The melt tension of the resin composition measured at 250°C is below 7.0 mN.

6. The resin composition according to claim 1 or 2, characterized in that: The crystallization peak of the resin composition from the propylene polymer (A), as measured by differential scanning calorimetry, is in the range of 120–135 °C.

7. The resin composition according to claim 1 or 2, characterized in that: The difference between the crystallization peak and the melting peak of the propylene polymer (A), as expressed by the following formula and measured by differential scanning calorimetry, of the resin composition is greater than 35°C. [Melting peak (°C) from propylene polymer (A)] - [Crystallization peak (°C) from propylene polymer (A)] 8. The resin composition according to claim 1 or 2, characterized in that: The nucleating agent is a noniol-based nucleating agent.

9. A laminated body, characterized in that: It has a layer comprising the resin composition according to any one of claims 1 to 8.

10. The laminate as described in claim 9, characterized in that: The laminate is a film used for food packaging.

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