Polypropylene resin composition for non-oriented film and sealant film

Abstract

The present invention provides a polypropylene resin composition for a non-stretch sealant film that enables reduction in resource consumption by reducing the thickness of the film, and more specifically, that has heat sealing properties suitable for a sealant material and maintains high rigidity even when made thin, and a non-stretch sealant film made of the polypropylene resin composition. [Solution] A polypropylene resin composition for use in unstretched films, comprising 1 to 30 mass% of a polypropylene resin (X) satisfying properties (X-1) to (X-6), and 99 to 70 mass% of a polypropylene resin (Y) satisfying properties (Y-1) to (Y-5) (wherein the total amount of the polypropylene resin (X) and the polypropylene resin (Y) is 100 mass%), and comprising 0.005 to 0.7 parts by weight of a nucleating agent (A) per 100 parts by weight of the total content of (X) and (Y).

Description

[Technical Field]

[0001] The present invention relates to a polypropylene resin composition for a non-stretched film, and more particularly to a polypropylene resin composition for a non-stretched film that can give a non-stretched film that is superior in optical properties such as transparency and has a good balance between heat sealability and rigidity compared to conventional polypropylene sealant films, and to a non-stretched sealant film made of the polypropylene resin composition. [Background technology]

[0002] Polypropylene is a typical general-purpose resin. Its films are widely used in the packaging industry due to their good balance of optical properties, mechanical properties, and packaging suitability, and are particularly popular for food packaging. In recent years, there has been a demand for thinner polypropylene films in order to improve productivity through high-speed film production, reduce weight and costs, and address environmental concerns. This also applies to sealant films, which require heat-sealing properties. However, thinning the film leads to a decrease in the stiffness, i.e., rigidity, of the film, which not only has a negative impact on transportability and ease of unwinding from a roll during film processing, but also leads to a decrease in the functions that the film should originally have, such as protecting the contents and maintaining the shape of the final package.

[0003] To solve this problem, methods have been proposed to increase the rigidity of films, including the addition of nucleating agents, which are crystallization promoters, and the addition of resin-reinforcing fillers such as talc, carbon nanofibers, and cellulose nanofibers. However, when inorganic nucleating agents are added, they become foreign matter and cause defects in the film's appearance known as fish eyes, and when organic dispersion-type nucleating agents are added, there is a risk that the low molecular weight components derived from the nucleating agent will contaminate the contents of the package.Furthermore, when resin-reinforced fillers are added, not only do they significantly change the texture, feel, and optical properties, but they also increase the specific gravity, which is not suitable for the purpose of reducing weight. Furthermore, there is also the problem that the presence of substances such as inorganic nucleating agents and organic reinforcing fillers leads to a decrease in heat sealability.

[0004] Furthermore, it is possible to increase rigidity by adjusting the film-forming conditions, such as by lowering the extrusion temperature to promote oriented crystallization or by increasing the cooling and solidification temperature to promote crystal growth. However, this is not a preferable method because it also results in a decrease in the heat-sealing properties of the sealant material, a deterioration in the thickness accuracy of the obtained film, and changes in the optical properties. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 9-272718 Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention aims to provide a polypropylene resin composition for a non-stretch sealant film which has higher rigidity and transparency than conventional polypropylene sealant films, and which can further reduce resource consumption by increasing the rigidity of the film; more specifically, a non-stretch sealant film which can maintain good heat sealability while maintaining high rigidity even when made thin, and a non-stretch sealant film made of the polypropylene resin composition. [Means for solving the problem]

[0007] [1] A polypropylene resin composition for use in an unstretched film, comprising 1 to 30 mass% of a polypropylene resin (X) that satisfies the following properties (X-1) to (X-6), and 99 to 70 mass% of a polypropylene resin (Y) that satisfies the following properties (Y-1) to (Y-5) (wherein the total amount of the polypropylene resin (X) and the polypropylene resin (Y) is 100 mass%), and comprising 0.005 to 0.7 parts by weight of a crystal nucleating agent (A) per 100 parts by weight of the total content of the polypropylene resin (X) and the polypropylene resin (Y). (X-1) MFR (230°C, load 2.16 kgf) is 0.1 to 30.0 g / 10 min. (X-2) The ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) obtained by GPC is 3.0 to 10.0. (X-3) The melt tension (MT) (unit: g) measured at 230°C satisfies the relationship of the following (Equation 1) or (Equation 2). log(MT)≧-0.9×log(MFR)+0.7 (Formula 1) MT≧15 (Formula 2) (X-4) Branching index g'(M abs ) is greater than or equal to 0.30 and less than 0.95. (X-5) 13 The mm fraction of propylene unit triads measured by C-NMR is 95% or more. (X-6) Polymerized using a metallocene catalyst (Y-1) The ethylene content is in the range of 1.0 to 6.0 mass %. (Y-2) MFR (230°C, load 2.16 kgf) is 1 to 30 g / 10 min. (Y-3) The ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) obtained by GPC is 2.0 to 4.0. (Y-4) Polymerized using a metallocene catalyst (Y-5) Branching index g'(M abs ) is between 0.95 and 1.0. [2] The polypropylene resin composition for use in a non-oriented film according to [1], wherein the polypropylene resin (Y) is a propylene-ethylene copolymer. [3] [1] or [2]. A non-stretched film comprising the polypropylene resin composition for non-stretched films. [4] [3] A film using the unstretched film described in [3] as a heat seal layer. [5] A multilayer film comprising a heat seal layer made of the non-stretched film according to [3]. [6] [3] A food packaging film comprising the unstretched film described in [3]. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a polypropylene resin composition for a non-stretch sealant film that has high rigidity even when made thin while maintaining good heat sealability, and a non-stretch sealant film made of the polypropylene resin composition. Furthermore, the present invention enables the thickness of the sealant film to be reduced, thereby reducing the amount of resin used, which not only reduces the production cost of the sealant film but is also excellent from the viewpoint of environmental issues. DETAILED DESCRIPTION OF THE INVENTION

[0009] The following describes in detail the embodiments of the present invention, item by item. In this specification, the use of "to" to indicate a range of values ​​means that the values ​​before and after the "to" range are included as the lower and upper limits. The following description of the constituent elements is an example of an embodiment of the present invention, and the present invention is not limited to these contents in any way.

[0010] 1. Polypropylene resin composition for non-oriented film The polypropylene resin composition for use in a non-oriented film of the present invention contains 1 to 30 mass% of a polypropylene resin (X) that satisfies the following properties (X-1) to (X-6), and 99 to 70 mass% of a polypropylene resin (Y) that satisfies the following properties (Y-1) to (Y-5) (wherein the total amount of the polypropylene resin (X) and the polypropylene resin (Y) is 100 mass%), and contains 0.005 to 0.7 parts by weight of a crystal nucleating agent (A) per 100 parts by weight of the total content of the polypropylene resin (X) and the polypropylene resin (Y). (X-1) MFR (230°C, load 2.16 kgf) is 0.1 to 30.0 g / 10 min. (X-2) The ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) obtained by GPC is 3.0 to 10.0. (X-3) The melt tension (MT) (unit: g) measured at 230°C satisfies the relationship of the following (Equation 1) or (Equation 2). log(MT)≧-0.9×log(MFR)+0.7 (Formula 1) MT≧15 (Formula 2) (X-4) Branching index g'(M abs ) is greater than or equal to 0.30 and less than 0.95. (X-5) 13 The mm fraction of propylene unit triads measured by C-NMR is 95% or more. (X-6) Polymerized using a metallocene catalyst (Y-1) The ethylene content is in the range of 1.0 to 6.0 mass %. (Y-2) MFR (230°C, load 2.16 kgf) is 1 to 30 g / 10 min. (Y-3) The ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) obtained by GPC is 2.0 to 4.0. (Y-4) Polymerized using a metallocene catalyst (Y-5) Branching index g'(M abs ) is between 0.95 and 1.0.

[0011] 1-1. Polypropylene resin (X) The polypropylene resin (X) satisfies the properties (X-1) to (X-6).

[0012] 1-1-1. Characteristics (X-1): MFR (230°C, load 2.16 kgf) is 0.1 to 30 g / 10 min. MFR is an index of melt fluidity, and the higher the molecular weight of a polymer, the smaller this value becomes. Conversely, the lower the molecular weight, the larger this value becomes. If the MFR is 0.1 g / 10 min or more, the melt flowability is good, the load on the extruder is low, and it is easy to form into a film. On the other hand, if the MFR is 30 g / 10 min or less, the melt tension is high, and necking and film rupture do not occur, making it easy to form into a film. Therefore, the MFR is 0.1 to 30 g / 10 min, preferably 1 to 20 g / 10 min, more preferably 2 to 15 g / 10 min, and even more preferably 7 to 10 g / 10 min. In the present invention, the melt flow rate (MFR) is a value measured in accordance with JIS K7210:2014 "Test method for melt mass flow rate (MFR) and melt volume flow rate (MVR) of plastics - thermoplastics" under test conditions of 230°C and a load of 2.16 kgf. The melt flow rate (MFR) can be easily adjusted by changing the temperature or pressure of the polymerization, or, as a general method, by adding a chain transfer agent such as hydrogen during the polymerization.

[0013] 1-1-2. Property (X-2): The ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) obtained by GPC is 3.0 to 10.0.

[0014] Mw / Mn is an index that indicates the breadth of the molecular weight distribution, and the larger this value, the broader the molecular weight distribution. If Mw / Mn is too small, the low molecular weight components decrease, resulting in poor melt fluidity. Therefore, if Mw / Mn is 3.0 or more, the low molecular weight components increase, improving melt fluidity. Mw / Mn is preferably 3.1 or more, more preferably 3.2 or more. On the other hand, if Mw / Mn is 10.0 or less, the high molecular weight components are relatively reduced, improving melt fluidity. Mw / Mn is preferably 9.6 or less, more preferably 9.2 or less.

[0015] Similarly, Mz / Mw is an index showing the spread of the molecular weight distribution, and is an index showing the spread toward the high molecular weight side compared to Mw / Mn. The larger these values, the broader the molecular weight distribution is toward the high molecular weight side. If Mz / Mw is 2 or more, the amount of high molecular weight components increases and the melt tension improves. Therefore, Mz / Mw is preferably 2.0 or more, more preferably 2.1 or more, and more preferably 2.2 or more. On the other hand, if Mz / Mw is 5 or less, the amount of high molecular weight components relatively decreases and the melt fluidity improves. Therefore, Mz / Mw is 5.0 or less, preferably 4.5 or less, and more preferably 4.0 or less.

[0016] The definitions of Mn, Mw, and Mz are described in "Fundamentals of Polymer Chemistry" (edited by the Society of Polymer Science, Tokyo Kagaku Dojin, 1978) and can be calculated from the molecular weight distribution curve obtained by GPC. The specific measurement method for GPC is as follows: Apparatus: Waters GPC (ALC / GPC 150C) Detector: FOXBORO MIRAN 1A IR detector (measurement wavelength: 3.42 μm) Column: Showa Denko AD806M / S (3 columns) Mobile phase solvent: o-dichlorobenzene ·Measurement temperature: 140℃ ·Flow rate: 1.0ml / min ·Injection amount: 0.2ml Sample preparation: Prepare a 1 mg / ml solution of the sample using o-dichlorobenzene (containing 0.5 mg / ml BHT) and dissolve it at 140°C for approximately 1 hour.

[0017] The conversion from the retention volume obtained by GPC measurement to molecular weight is carried out using a calibration curve prepared in advance using standard polystyrene (PS). The standard polystyrenes used are all the following brands manufactured by Tosoh Corporation. F380, F288, F128, F80, F40, F20, F10, F4, F1, A5000, A2500, A1000. A calibration curve was created by dissolving each compound in ODCB (containing 0.5 mg / ml of BHT) at 0.5 mg / ml and injecting 0.2 ml of the solution. The calibration curve was calculated using a cubic equation obtained by approximating the curve using the least squares method. The viscosity formula used to convert to molecular weight is [η] = K × M α The following values ​​are used: PS:K = 1.38 × 10 -4 , α=0.7 PP:K = 1.03 × 10 -4 , α=0.78

[0018] 1-1-3. Property (X-3): The melt tension measured at 230°C (MT; can also be written as MT230°C) (unit: g) satisfies the requirements of the following (Equation 1) or (Equation 2). log(MT)≧-0.9×log(MFR)+0.7 (Formula 1) MT≧15 (Formula 2)

[0019] Here, MT230°C represents the melt tension measured using a Toyo Seiki Seisakusho Capillograph 1B under the following conditions: capillary diameter: 2.0 mm, length: 40 mm, cylinder diameter: 9.55 mm, cylinder extrusion speed: 20 mm / min, take-up speed: 4.0 m / min, and temperature: 230°C, and the unit is grams. However, if the sample resin breaks at a take-up speed of 4.0 m / min, the take-up speed is changed to 2.0 m / min, and the melt tension at that time is taken as MT. The measurement conditions and units for MFR are as described above.

[0020] (Equation 1) is an index for ensuring that polypropylene resin (X) has sufficient melt tension, and since MT generally correlates with MFR, it is expressed by a relational expression with MFR. The relational expression between MT and MFR is expressed by (Equation 1): log(MT)≧−0.9×log(MFR)+0.7, preferably log(MT)≧−0.9×log(MFR)+1.0 (Equation 1a), and more preferably log(MT)≧−0.9×log(MFR)+1.5 (Equation 1b). If the polypropylene resin (X) satisfies the above formula (1), not only can it reduce neck-in, but also it can uniformly propagate stress in the molten film, thereby suppressing the phenomenon of uneven film thickness known as the resonance phenomenon and instability due to expansion and contraction of the edge portions.

[0021] Furthermore, if the polypropylene resin (X) satisfies the above (formula 2), it has a melt tension sufficient for practical use, improves molding stability, and suppresses, for example, defects in film appearance known as the sharkskin phenomenon.

[0022] The polypropylene resin (X) must satisfy the requirements of (formula 1) or (formula 2), and in this case, the rigidity of the film will be high.

[0023] Regarding the upper limit of MT, if MT is 40 g or less, the resin is extensible and film breakage during molding does not occur. Therefore, MT is preferably 40 g or less, more preferably 37 g or less, and even more preferably 35 g or less. To satisfy the requirement of the above formula (1), for example, the melt tension may be increased by increasing the amount of long chain branches in the polypropylene resin (X). For example, it is possible to introduce a large amount of long chain branches by controlling the types, combinations, amount ratios, prepolymerization conditions, etc. of the preferred metallocene catalysts described below.

[0024] 1-1-4. Properties (X-4): Branching index g' (M abs ) is greater than or equal to 0.30 and less than 0.95.

[0025] The branching index g' can be used as a direct indicator of whether polypropylene resin (X) has branches. g' is given by the ratio of the intrinsic viscosity [η]br of a polymer with long chain branches to the intrinsic viscosity [η]lin of a linear polymer with the same molecular weight, i.e., [η]br / [η]lin, and takes a value smaller than 1 when long chain branches are present. In other words, polypropylene with g'<1 is a "long-chain branched polypropylene." The definition is described, for example, in "Developments in Polymer Characterization-4" (JV Dawkins ed., Applied Science Publishers, 1983), and is a guide known to those skilled in the art.

[0026] g' can be obtained as a function of the absolute molecular weight Mabs, for example, by using GPC equipped with a light scattering meter and a viscometer as detectors as described below. The polypropylene resin (X) used in the present invention has a molecular weight (M) of 1 million as determined by light scattering. abs ) is 0.30 or more and less than 0.95, preferably 0.40 or more and less than 0.93, more preferably 0.50 or more and less than 0.92, and even more preferably 0.60 or more and less than 0.91. g'(M abs ) is 0.30 or more, highly cross-linked components are not formed, and gel formation is absent or very minimal. abs ) is less than 0.95, the performance of the resin that forms a long chain branched structure is exerted, and rigidity is increased.

[0027] A specific method for calculating g' is as follows. The GPC system used is a Waters Alliance GPCV2000 equipped with a differential refractometer (RI) and a viscosity detector (Viscometer). The light scattering detector used is a Wyatt Technology DAWN-E multi-angle laser light scattering detector (MALLS). The detectors are connected in the following order: MALLS, RI, and Viscometer. The mobile phase solvent is 1,2,4-trichlorobenzene (added with 0.5 mg / mL of the antioxidant Irganox 1076 manufactured by BASF Japan). The flow rate was 1 mL / min, and two connected Tosoh GMHHR-H(S) HT columns were used. The temperatures of the columns, sample injection port, and detectors were 140°C. The sample concentration was 1 mg / mL, and the injection volume (sample loop volume) was 0.2175 mL. Absolute molecular weight (M abs ), the root mean square radius of gyration (Rg), and the intrinsic viscosity ([η]) obtained from the Viscometer are calculated using the data processing software ASTRA (version 4.73.04) attached to MALLS, with reference to the following literature: References: 1. “Developments in Polymer Characterization-4” (JV Dawkins ed. Applied Science Publishers, 1983.Chapter1.) 2.Polymer,45,6495-6505(2004) 3.Macromolecules,33,2424-2436(2000) 4.Macromolecules,33,6945-6952(2000)

[0028] [Calculation of branching index (g')] The branching index (g') is calculated as the ratio ([η]br / [η]lin) of the intrinsic viscosity ([η]br) obtained by measuring a sample with the above-mentioned viscometer to the intrinsic viscosity ([η]lin) obtained by separately measuring a linear polymer. When long-chain branching is introduced into a polymer molecule, the radius of gyration becomes smaller compared to a linear polymer molecule of the same molecular weight. As the radius of gyration decreases, the intrinsic viscosity also decreases. Therefore, as long-chain branching is introduced, the ratio of the intrinsic viscosity ([η]br) of the branched polymer to the intrinsic viscosity ([η]lin) of a linear polymer of the same molecular weight ([η]br / [η]lin) decreases. Therefore, when the branching index (g'=[η]br / [η]lin) is a value smaller than 1, it means that the polymer has a long-chain branched structure. Here, a commercially available homopolypropylene (Novatec PP (registered trademark) grade name: FY6 manufactured by Japan Polypropylene Corporation) is used as the linear polymer for obtaining [η]lin. The fact that the logarithm of [η]lin of a linear polymer has a linear relationship with the logarithm of the molecular weight is known as the Mark-Houwink-Sakurada equation, and therefore the value of [η]lin can be obtained by appropriately extrapolating to the low molecular weight side or the high molecular weight side.

[0029] The branching index g' can be set to 0.30 or more but less than 0.95 by introducing a large amount of long chain branches, for example, by controlling the type of metallocene catalyst, the combined amount ratio, prepolymerization conditions, etc.

[0030] 1-1-5.Characteristics (X-5): 13 The mm fraction of propylene unit triads measured by C-NMR is 95% or more.

[0031] The polypropylene resin (X) of the present invention preferably has high stereoregularity. The degree of stereoregularity is as follows: 13 can be evaluated by C-NMR, 13 The stereoregularity is preferably such that the mm fraction of propylene unit triads obtained by C-NMR is 95% or more. The mm fraction is the percentage of propylene unit triads in which the methyl branching direction in each propylene unit is the same among any propylene unit triads consisting of head-to-tail bonds in the polymer chain, and therefore has an upper limit of 100%. This mm fraction is a value that indicates whether the stereostructure of the methyl groups in the polypropylene molecular chain is isotactically controlled, and the higher the mm fraction, the higher the degree of control. If the mm fraction is higher than a certain value, the elastic modulus of the product will be improved and the film will have higher rigidity. Therefore, the mm fraction is 95% or more, preferably 96% or more, and more preferably 97% or more.

[0032] In addition, 13 The details of the method for measuring the mm fraction of propylene unit triads by C-NMR are as follows. 375 mg of sample was completely dissolved in 2.5 ml of deuterated 1,1,2,2-tetrachloroethane in an NMR sample tube (10 mm diameter), and then measured at 125°C using the proton complete decoupling method. The chemical shift was set to 74.2 ppm based on the central peak of the three peaks of deuterated 1,1,2,2-tetrachloroethane. The chemical shifts of the other carbon peaks were based on this peak. Flip angle: 90 degrees Pulse interval: 10 seconds ·Resonance frequency: 100MHz or more Accumulation count: 10,000 or more Observation range: -20 ppm to 179 ppm Number of data points: 32768

[0033] The mm fraction of propylene unit triads is 13 Measured by C-NMR 13 The integrated intensity of the C signal is calculated by substituting it into the following equation: mm(%) = Imm × 100 / (Imm + 3 × Imrrm) where Imm=I 23.6~21.1 , Imrrm=I 19.8~19.7 This is the quantity shown below. To calculate the mm fraction of propylene unit triads 13C-NMR measurement can be performed in the same manner as the above measurement. Spectral assignments can be made with reference to Polymer Jounral, Vol. 16, p. 717 (1984), Asakura Shoten, Macromolecules, Vol. 8, p. 687 (1975), and Polymer, Vol. 30, p. 1350 (1989).

[0034] The mm fraction of 95% or more can be achieved by using a polymerization catalyst that produces a highly crystalline polymer, and this can be achieved by using a preferred metallocene catalyst described below for polymerization.

[0035] 1-1-6. Manufacturing method of polypropylene resin (X) The polypropylene resin (X) must be polymerized using a metallocene catalyst (characteristic (X-6)). This allows the polypropylene resin (X) to have high stereoregularity, a relatively wide molecular weight distribution, and a branching index g' (M abs ) range, high melt tension, etc. Examples of metallocene catalysts include (i) transition metal compounds of Group 4 of the periodic table containing a ligand having a cyclopentadienyl skeleton, (ii) co-catalysts that can be activated to a stable ionic state by reacting with a metallocene compound, and (iii) catalysts that comprise a co-catalyst that can be activated to a stable ionic state by reacting with a metallocene compound and an organoaluminum compound. In order to improve the mechanical properties of the polypropylene resin (X), the metallocene catalyst used to synthesize the polypropylene resin (X) is preferably a crosslinked metallocene compound capable of stereoregular polymerization of propylene, and more preferably a crosslinked metallocene compound capable of isoregular polymerization of propylene. The metallocene compounds of (i) are described in JP-A-60-35007, JP-A-61-130314, JP-A-63-295607, JP-A-1-275609, JP-A-2-41303, JP-A-2-131488, JP-A-2-76887, JP-A-3-163088, JP-A-4-300887, JP-A-4-211694, JP-A-5-43616, JP-A-5-209013, JP-A-6-239914, JP-T-504934 and JP-A-85708. Specific examples of the metallocene compound (i) include: Methylenebis(2-methylindenyl)zirconium dichloride, ethylenebis(2-methylindenyl)zirconium dichloride, Ethylene 1,2-(4-phenylindenyl)(2-methyl-4-phenyl-4H-azulenyl)zirconium dichloride, isopropylidene(cyclopentadienyl)(fluorenyl)zirconium dichloride, isopropylidene(4-methylcyclopentadienyl)(3-t-butylindenyl)zirconium dichloride, dimethylsilylene(2-methyl-4-t-butyl-cyclopentadienyl)(3'-t-butyl-5'-methyl-cyclopentadienyl)zirconium dichloride, dimethylsilylenebis(indenyl)zirconium dichloride, Dimethylsilylenebis(4,5,6,7-tetrahydroindenyl)zirconium dichloride Lido, dimethylsilylenebis[1-(2-methyl-4-phenylindenyl)]zirconium dichloride, dimethylsilylenebis[1-(2-ethyl-4-phenylindenyl)]zirconium dichloride, dimethylsilylenebis[4-(1-phenyl-3-methylindenyl)]zirconium dichloride, Dimethylsilylene(fluorenyl) t-butylamido zirconium dichloride, Methylphenylsilylenebis[1-(2-methyl-4-(1-naphthyl)-indenyl)]zirconium dichloride, dimethylsilylenebis[1-(2-methyl-4,5-benzoindenyl)]zirconium dichloride, dimethylsilylenebis[1-(2-methyl-4-phenyl-4H-azulenyl)]zirconium dichloride, dimethylsilylenebis[1-(2-ethyl-4-(4-chlorophenyl)-4H-azulenyl)]zirconium dichloride, dimethylsilylenebis[1-(2-ethyl-4-naphthyl-4H-azulenyl)]zirconium dichloride, Diphenylsilylenebis[1-(2-methyl-4-(4-chlorophenyl)-4H-azulenyl)]zirconium dichloride, dimethylsilylenebis[1-(2-ethyl-4-(3-fluorobiphenylyl)-4H-azulenyl)]zirconium dichloride, Examples of zirconium compounds include dimethylgermylenebis[1-(2-ethyl-4-(4-chlorophenyl)-4H-azulenyl)]zirconium dichloride and dimethylgermylenebis[1-(2-ethyl-4-phenylindenyl)]zirconium dichloride. The metallocene compound (i) in which the zirconium is replaced with titanium or hafnium, and / or a mixture thereof, can also be used as a polymerization catalyst for producing polypropylene resin (X). The metallocene compound (i) in which the chloride is replaced with other halogen compounds, hydrocarbon groups such as methyl, isobutyl, and benzyl, amide groups such as dimethylamide and diethylamide, alkoxide groups such as methoxy and phenoxy, and hydride groups can also be used as a polymerization catalyst for producing polypropylene resin (X). The metallocene compound (i) which is a polymerization catalyst for producing the polypropylene resin (X) is preferably a metallocene compound in which an indenyl group or an azulenyl group is crosslinked with a silicon or germyl group. The polymerization catalyst for producing polypropylene resin (X) may be supported on an inorganic or organic compound. To improve the production yield of polypropylene resin (X), the support is preferably porous. The support is preferably an inorganic compound such as ion-exchangeable layered silicate, zeolite, SiO2, Al2O3, silica-alumina, MgO, ZrO2, TiO2, B2O3, CaO, ZnO, BaO, or ThO2; an organic compound such as porous polyolefin, styrene-divinylbenzene copolymer, or olefin-acrylic acid copolymer; or a mixture thereof. To improve the production yield of the polypropylene resin (X), it is preferable to use a co-catalyst together with the metallocene compound (ii). The co-catalyst is preferably an organoaluminum oxy-compound such as an aluminoxane compound, an ion-exchange layered silicate, a Lewis acid, a boron-containing compound, an ionic compound, or a fluorine-containing organic compound. In order to improve the productivity of the polypropylene resin (X), the organoaluminum compound (iii) is preferably a trialkylaluminum such as triethylaluminum, triisopropylaluminum, or triisobutylaluminum, a dialkylaluminum halide, an alkylaluminum sesquihalide, an alkylaluminum dihalide, an alkylaluminum hydride, or an organoaluminum alkoxide.

[0036] The polypropylene resin (X) is preferably produced by a method using a macromer copolymerization method utilizing a combination of metallocene catalysts. An example of a method using a macromer copolymerization method utilizing a combination of metallocene catalysts is the method disclosed in Japanese Patent Application Laid-Open No. 2009-57542. This method produces polypropylene having long-chain branches using a catalyst that combines a catalyst component with a specific structure capable of generating macromers and a catalyst component with a specific structure capable of copolymerizing macromers. This method enables the production of polypropylene resins having long-chain branches with the desired physical properties by industrially effective methods such as bulk polymerization or gas-phase polymerization, particularly single-stage polymerization under practical pressure and temperature conditions, and using hydrogen as a molecular weight modifier. The macromer copolymerization method can produce polypropylene resins containing long-chain branches without gel formation, making it suitable for the present invention. Furthermore, since the polypropylene resins produced by the macromer copolymerization method are not crosslinked, they are easily recyclable.

[0037] The polypropylene resin (X) used in the present invention may be a propylene homopolymer obtained by homopolymerizing a propylene monomer, or a propylene-α-olefin copolymer obtained by copolymerizing a propylene monomer with an α-olefin comonomer having 2 to 20 carbon atoms other than propylene, such as ethylene and / or 1-butene. The form of the polypropylene resin (X) is not particularly limited, and it may be in the form of a powder or a particulate product thereof.

[0038] The polypropylene resin (X) may be mixed with other additional components described below as needed using a Henschel mixer, V blender, ribbon blender, tumbler blender, or the like, and may also be kneaded into granules using a kneading machine such as a single-screw extruder, multi-screw extruder, kneader, or Banbury mixer, as needed.

[0039] 1-2. Polypropylene resin (Y) The polypropylene resin (Y) satisfies the properties (Y-1) to (Y-5).

[0040] 1-2-1. Property (Y-1): Ethylene content is in the range of 1.0 to 6.0 mass %. The ethylene content in the polypropylene resin (Y) is 1.0 to 6.0% by mass, preferably 1.0 to 4.0% by mass. When the ethylene content is within the above range, the melting point (Tm) of the polypropylene resin (Y) decreases, and the resin has excellent heat-sealing properties without decreasing rigidity. The ethylene content in the polypropylene resin (Y) can be adjusted by the ethylene ratio in the gas components in the polymerization vessel. Specifically, increasing the ethylene ratio increases the ethylene content in the polypropylene resin (Y). The reverse is also true. In order to increase the ethylene ratio in the polymerization vessel, it is sufficient to increase the amount of ethylene supplied to the polymerization vessel, and adjustment is extremely easy for those skilled in the art.

[0041] 1-2-2. Characteristics (Y-2): MFR (230°C, load 2.16 kgf) is 1 g / 10 min to 30 g / 10 min. The MFR of the polypropylene resin (Y) is 1 to 30 g / 10 min, preferably 2 to 25 g / 10 min. When the MFR is 1 g / 10 min or more, the polypropylene resin composition has good fluidity and is less likely to undergo melt fracture during film formation. On the other hand, when the MFR is 30 g / 10 min or less, the polypropylene resin composition has good melt tension, which can reduce necking and improve the production efficiency of the product. The MFR of the polypropylene resin (Y) can be easily adjusted by changing the temperature and pressure conditions of propylene polymerization, or by adding a chain transfer agent such as hydrogen during polymerization.

[0042] 1-2-3. Property (Y-3): The ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) obtained by GPC is 2.0 to 4.0. Using a metallocene catalyst can lower the Mw / Mn ratio compared to using a Ziegler-Natta catalyst. However, controlling the Mw / Mn ratio can be achieved by selecting an appropriate metallocene catalyst for the desired value and also by adjusting the polymerization conditions. For example, by using a two-stage continuous polymerization process and producing propylene-ethylene copolymers with different molecular weights in the first and second stages, it is possible to achieve a higher Mw / Mn ratio than the value inherently achieved by the metallocene catalyst. In this case, it is easy for those skilled in the art to understand the polymerization conditions, particularly the relationship between the hydrogen concentration and the molecular weight of the resulting propylene-ethylene copolymer, and then adjust the hydrogen concentration in each reactor appropriately to achieve the desired Mw / Mn ratio.

[0043] The definitions of Mn, Mw, and Mz and the specific measurement methods are the same as those described in requirement (X-2).

[0044] 1-2-4. Manufacturing method of polypropylene resin (Y) The polypropylene resin (Y) must be polymerized using a metallocene catalyst (characteristic (Y-4)). This narrows the molecular weight distribution and crystallinity distribution of the polypropylene resin (Y). As a result, the polypropylene resin (Y) can have a low melting point, good heat sealability, and high rigidity. The metallocene catalyst is a catalyst comprising (i) a transition metal compound of Group 4 of the periodic table containing a ligand having a cyclopentadienyl skeleton (a so-called metallocene compound), (ii) a co-catalyst capable of activating the metallocene compound to a stable ionic state by reacting with the metallocene compound, and, if necessary, (iii) an organoaluminum compound, and any known catalyst can be used. The metallocene compound is preferably a bridged metallocene compound capable of stereoregular polymerization of propylene, and more preferably a bridged metallocene compound capable of isoregular polymerization of propylene.

[0045] As the (i) metallocene compound, for example, those disclosed in JP-A-60-35007, JP-A-61-130314, JP-A-63-295607, JP-A-1-275609, JP-A-2-41303, JP-A-2-131488, JP-A-2-76887, JP-A-3-163088, JP-A-4-300887, JP-A-4-211694, JP-A-5-43616, JP-A-5-209013, JP-A-6-239914, JP-T-7-504934, and JP-A-8-85708 can be preferably used.

[0046] Furthermore, specifically, Methylenebis(2-methylindenyl)zirconium dichloride, ethylenebis(2-methylindenyl)zirconium dichloride, Ethylene 1,2-(4-phenylindenyl)(2-methyl-4-phenyl-4H-azulenyl)zirconium dichloride, Isopropylidene(cyclopentadienyl)(fluorenyl)zirconium dichloride, isopropylidene(4-methylcyclopentadienyl)(3-t-butylindenyl)zirconium dichloride, dimethylsilylene(2-methyl-4-t-butyl-cyclopentadienyl)(3'-t-butyl-5'-methyl-cyclopentadienyl)zirconium dichloride, dimethylsilylenebis(indenyl)zirconium dichloride, dimethylsilylenebis(4,5,6,7-tetrahydroindenyl)zirconium dichloride, dimethylsilylenebis[1-(2-methyl-4-phenylindenyl)]zirconium dichloride, dimethylsilylenebis[1-(2-ethyl-4-phenylindenyl)]zirconium dichloride, dimethylsilylenebis[4-(1-phenyl-3-methylindenyl)]zirconium dichloride, Dimethylsilylene(fluorenyl) t-butylamido zirconium dichloride, Methylphenylsilylenebis[1-(2-methyl-4-(1-naphthyl)-indenyl)]zirconium dichloride, dimethylsilylenebis[1-(2-methyl-4,5-benzoindenyl)]zirconium dichloride, dimethylsilylenebis[1-(2-methyl-4-phenyl-4H-azulenyl)]zirconium dichloride, dimethylsilylenebis[1-(2-ethyl-4-(4-chlorophenyl)-4H-azulenyl)]zirconium dichloride, dimethylsilylenebis[1-(2-ethyl-4-naphthyl-4H-azulenyl)]zirconium dichloride, Diphenylsilylenebis[1-(2-methyl-4-(4-chlorophenyl)-4H-azulenyl)]zirconium dichloride, dimethylsilylenebis[1-(2-ethyl-4-(3-fluorobiphenylyl)-4H-azulenyl)]zirconium dichloride, dimethylgermylenebis[1-(2-ethyl-4-(4-chlorophenyl)-4H-azulenyl)]zirconium dichloride, Dimethylgermylenebis[1-(2-ethyl-4-phenylindenyl)]zirconium dichloride Examples of zirconium compounds include:

[0047] In the above, compounds in which zirconium is replaced with titanium or hafnium can also be used. It is also preferable to use a mixture of a zirconium compound and a hafnium compound. Chloride can also be replaced with other halogen compounds, hydrocarbon groups such as methyl, isobutyl, and benzyl, amide groups such as dimethylamide and diethylamide, alkoxide groups such as methoxy and phenoxy, and hydride groups. Among these, metallocene compounds in which an indenyl group or an azulenyl group is crosslinked with a silicon or germyl group are particularly preferred. The metallocene compound may be used by supporting it on an inorganic or organic carrier. The carrier is preferably a porous inorganic or organic compound, and specific examples include inorganic compounds such as ion-exchangeable layered silicates, zeolites, SiO2, Al2O3, silica alumina, MgO, ZrO2, TiO2, B2O3, CaO, ZnO, BaO, and ThO2, organic compounds such as porous polyolefins, styrene-divinylbenzene copolymers, and olefin-acrylic acid copolymers, or mixtures thereof.

[0048] Preferred examples of the co-catalyst (ii) capable of reacting with the metallocene compound to activate it to a stable ionic state include organoaluminum oxy-compounds (e.g., aluminoxane compounds), ion-exchangeable layered silicates, Lewis acids, boron-containing compounds, ionic compounds, and fluorine-containing organic compounds.

[0049] Furthermore, preferred examples of the organoaluminum compound (iii) include trialkylaluminums such as triethylaluminum, triisopropylaluminum, and triisobutylaluminum, dialkylaluminum halides, alkylaluminum sesquihalides, alkylaluminum dihalides, alkylaluminum hydrides, and organoaluminum alkoxides.

[0050] The method for producing polypropylene resin (Y) is not particularly limited and may be single-stage or multi-stage polymerization. It can also be produced by any of the conventionally known methods, such as slurry polymerization, bulk polymerization, or gas-phase polymerization. Supercritical conditions can also be used as intermediate conditions between bulk and gas-phase processes. However, since these are essentially equivalent to gas-phase processes, they are included in the gas-phase process without any particular distinction. Furthermore, multi-stage polymerization can also be used to produce polypropylene and propylene-ethylene copolymers. A bulk polymerization reactor may be followed by a gas-phase polymerization reactor. In this case, the process will be referred to as a bulk process, in accordance with industry practice. In addition, in the case of a batch process, the first step may be performed by a bulk process and the second step by a gas-phase process. This case will also be referred to as a bulk process. Various processes have been proposed for both bulk and gas-phase processes. While there are differences in the agitation (mixing) method and heat removal method, the present invention does not particularly limit the type of process.

[0051] The polypropylene resin (Y) according to the present invention can be obtained by mixing, as necessary, other additional components described below using a Henschel mixer, a V blender, a ribbon blender, a tumbler blender or the like, and, as necessary, by kneading using a kneader such as a single-screw extruder, a multi-screw extruder, a kneader or a Banbury mixer.

[0052] The polypropylene resin (Y) may be a propylene-α-olefin copolymer obtained by copolymerizing a propylene monomer with an α-olefin comonomer having 2 to 20 carbon atoms other than propylene, such as ethylene and / or 1-butene. As defined by characteristic (Y-1), polypropylene resin (Y) contains 1.0 to 6.0 mass% of ethylene as a comonomer. More preferably, it contains 1.0 to 5.0 mass%, and even more preferably, it contains 1.0 to 4.0 mass% of ethylene. When the ethylene content is 1.0 mass% or more, the melting point (Tm) decreases, resulting in excellent heat-sealing properties. When the ethylene content is 6.0 mass% or less, high crystallinity is achieved, resulting in high rigidity and heat resistance.

[0053] In a preferred embodiment of the polypropylene resin composition for a non-oriented film of the present invention, the polypropylene resin (Y) is a propylene-ethylene copolymer. When the polypropylene resin (Y) is a propylene-ethylene copolymer, the melting point (Tm) is lowered, resulting in excellent heat-sealability.

[0054] The form of the polypropylene resin (Y) is not particularly limited, and it may be in the form of a powder or a particulate product thereof.

[0055] 1-2-5. Properties (Y-5): Branching index g' (M abs ) is between 0.95 and 1.0. The polypropylene resin (Y) has a branching index g' of 0.95 or more and 1.0 or less, preferably 0.98 or more and 1.0 or less. The polypropylene resin (Y) has a branching index g'(M abs ) is within the above range, fisheyes resulting from the long-chain branched structure are reduced, making it suitable for a sealant film. In addition, the branching index g'(M abs The meaning of ) and the specific method for calculating g' are as described in characteristic (X-4).

[0056] 1-2-6. Other properties of polypropylene resin (Y) The polypropylene resin (Y) preferably has a melt tension (MT) (unit: g) of 0.1 or more and less than 1.0. When the melt tension (MT) of the polypropylene resin (Y) is in the above range, the extrusion torque during molding is lowered, allowing the amount of electricity used in production to be reduced, and the shear stress in the extruder is reduced, allowing thermal degradation of the resin to be suppressed. Moreover, the polypropylene resin (Y) does not include those that fall under the category of the polypropylene resin (X).

[0057] 1-3. Polypropylene resin composition for non-oriented film 1-3-1. Ratio of polypropylene resin (X) and polypropylene resin (Y) The proportions of the polypropylene resin (X) and the polypropylene resin (Y) in the polypropylene resin composition for a non-oriented film of the present invention, based on 100% by mass of the total content of (X) and (Y), are 1 to 30% by mass for the polypropylene resin (X) and 99 to 70% by mass for the polypropylene resin (Y), preferably 5 to 20% by mass for the polypropylene resin (X) and 95 to 80% by mass for the polypropylene resin (Y), more preferably 5 to 15% by mass for the polypropylene resin (X) and 95 to 85% by mass for the polypropylene resin (Y). By adjusting the content within the above range, it is possible to obtain a polypropylene resin composition for use in a non-oriented film that does not impair the excellent heat sealing properties required for a sealant, has high rigidity, and has an improved transparency balance.

[0058] The polypropylene resin composition for a non-oriented film of the present invention essentially contains a crystal nucleating agent (A). By containing a crystal nucleating agent, the polypropylene resin composition for a non-oriented film of the present invention has low haze even when its rigidity is increased. The content of the crystal nucleating agent (A) is 0.005 to 0.7 parts by weight, preferably 0.01 to 0.7 parts by weight, and more preferably 0.01 to 0.6 parts by weight, relative to 100 parts by weight of the total content of the polypropylene resin (X) and the polypropylene resin (Y). By ensuring that the content of the crystal nucleating agent (A) is within the above range, bleeding onto the surface during film formation is less likely to occur, preventing contamination of processing rolls. Furthermore, by ensuring uniform dispersion throughout the resin composition, a film with excellent appearance and fewer fisheyes can be obtained.

[0059] Nucleating agents are classified into organic and inorganic types, and organic nucleating agents are preferred in the present invention, such as sorbitol-based nucleating agents, amide-based nucleating agents, and phosphate ester-based nucleating agents. Amide-based nucleating agents are nucleating agents having an amide group. Examples of amide-based nucleating agents include 1,3,5-tris(2,2-dimethylpropanamido)benzene, N,N',N''-tris(2-methylcyclohexyl)propane-1,2,3-tricarboxamide, N,N'-dicyclohexyl-2,6-naphthalenedicarboxamide, and N,N',N''-tricyclohexyl-trimesic acid amide. Sorbitol-based nucleating agents are sorbitol derivatives, such as 1-[8-propyl-2,6-bis(4-propylphenyl)tetrahydro[1,3]dioxino[5,4-d][1,3]dioxin-4-yl]ethane-1,2-diol, 1,3:2,4-bis-O-(3,4-dimethylbenzylidene)-D-sorbitol, 1-O,3-O:2-O,4-O-bis(4-methylbenzylidene)-D-glucitol, and 1,3:2,4-O-bis(4-ethylbenzylidene)-sorbitol. The nucleating agent may be a mixture of multiple nucleating agents. The amide-based crystal nucleating agent is used in an amount of preferably 0.005 to 0.04 parts by weight, more preferably 0.01 to 0.03 parts by weight, per 100 parts by weight of the total content of polypropylene resin (X) and polypropylene resin (Y), in order to comply with official regulations and / or to increase rigidity without impairing heat sealability as a sealant material. The sorbitol-based crystal nucleating agent is used in an amount of preferably 0.01 to 0.7 parts by weight, more preferably 0.1 to 0.6 parts by weight, per 100 parts by weight of the total content of polypropylene resin (X) and polypropylene resin (Y), in order to comply with official regulations and / or to enhance rigidity without impairing heat sealability as a sealant material. The content of the phosphate ester-based crystal nucleating agent is preferably 0.005 to 0.6 parts by weight, more preferably 0.01 to 0.3 parts by weight, per 100 parts by weight of the total content of the polypropylene resin (X) and the polypropylene resin (Y), in order to comply with official regulations and / or to increase rigidity without impairing heat sealability as a sealant material.

[0060] In addition to the above, examples of the nucleating agent (A) contained in the polypropylene resin composition for use in an unstretched film of the present invention include sodium 2,4,8,10-tetra-tert-butyl-6-oxo-12H-dibenzo[d,g][1,3,2]dioxaphosphocin-6-olate, zinc stearate, aluminum bis(4-tert-butylbenzoato-κO) hydroxide, aluminum bis(4,4',6,6'-tetra-tert-butyl-2,2'-methylenediphenyl phosphate) hydroxide, 1-O,3-O:2-O,4-O-bis(4-methylbenzylidene)-D-glucitol, N,N'-dicyclohexyl-2,6-naphthalenedicarboxamide, and 1,3,5-tris(2,2-dimethylpropanamido)benzene.

[0061] The crystal nucleating agent (A) can be mixed with the polypropylene resin (X) and the polypropylene resin (Y) to form a polypropylene resin composition for use in an unstretched film. The nucleating agent (A) can also be incorporated into a resin and used as a masterbatch. For example, a masterbatch containing the nucleating agent (A) can be prepared using one or more of polypropylene resin (X), polypropylene resin (Y), or a resin that does not fall into either of the polypropylene resin (X) and polypropylene resin (Y), and then mixed with polypropylene resin (X) and polypropylene resin (Y) to prepare a polypropylene resin composition for a non-oriented film.

[0062] 1-3-3. Other ingredients The polypropylene resin composition for a non-oriented film of the present invention can be used by adding, as necessary, the following various components other than the polypropylene resin (X), polypropylene resin (Y) and crystal nucleating agent (A).

[0063] 1-3-3-1. Additives Additives such as antioxidants that can be added to propylene-based resins can be added appropriately to the polypropylene resin composition for use in a non-oriented film of the present invention, as long as they do not significantly impair the effects of the present invention. Specifically, phenolic stabilizers such as 2,6-di-t-butyl-p-cresol (BHT), tetrakis[methylene-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate]methane (manufactured by BASF Japan Ltd., trade name "IRGANOX 1010") and n-octadecyl-3-(4'-hydroxy-3,5'-di-t-butylphenyl)propionate (manufactured by BASF Japan Ltd., trade name "IRGANOX 1076"), phosphite stabilizers such as bis(2,4-di-t-butylphenyl)pentaerythritol diphosphite and tris(2,4-di-t-butylphenyl)phosphite, lubricants such as higher fatty acid amides and higher fatty acid esters, antistatic agents such as glycerin esters, sorbitan acid esters, and polyethylene glycol esters of fatty acids having 8 to 22 carbon atoms, and antiblocking agents such as silica, calcium carbonate, and talc may be added.

[0064] In addition, ultraviolet absorbers and light stabilizers can be added to impart weather resistance. UV absorbers are compounds that have an absorption band in the ultraviolet region, and known types include triazoles, benzophenones, salicylates, cyanoacrylates, nickel chelates, and inorganic fine particles. Of these, the most commonly used are triazoles. Hindered amine compounds are commonly used as light stabilizers, and are known as HALS.

[0065] 1-3-3-2.Other polymers To the polypropylene resin composition for a non-oriented film of the present invention, an elastomer that can be added to a propylene-based resin may be added as appropriate, as long as the effect of the present invention is not impaired. Of the above, an ethylene-α-olefin copolymer is used as the elastomer. The α-olefin is preferably an α-olefin having 3 to 18 carbon atoms. Specific examples include propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-heptene, 4-methyl-pentene-1, 4-methyl-hexene-1, and 4,4-dimethylpentene-1. The α-olefin may be one type or a combination of two or more types. From the viewpoint of flexibility, the α-olefin content is preferably 30% by mass or more.

[0066] Furthermore, a styrene-based elastomer can also be added. The styrene-based elastomer can be appropriately selected from commercially available products and used. For example, hydrogenated styrene-butadiene block copolymers are sold by Kraton Polymer Japan Co., Ltd. under the trade name "Kraton G" and by Asahi Chemicals Co., Ltd. under the trade name "Tuftec," hydrogenated styrene-isoprene block copolymers are sold by Kuraray Co., Ltd. under the trade name "Septon," hydrogenated styrene-vinylated polyisoprene block copolymers are sold by Kuraray Co., Ltd. under the trade name "Hybler," and hydrogenated styrene-butadiene random copolymers are sold by ENEOS Materials Corporation under the trade name "Dynalon." An appropriate elastomer can be selected from these product groups and used.

[0067] When other polymers are blended, the amount is preferably 2 to 30 parts by weight, more preferably 3 to 25 parts by weight, and even more preferably 5 to 20 parts by weight, relative to 100 parts by weight of the total of polypropylene resin (X) and polypropylene resin (Y). When the blending amount of other polymers such as polyethylene resins is within the above range, the melting point (Tm) is lowered and the heat sealability is excellent.

[0068] The polypropylene resin composition for a non-oriented film of the present invention can be blended with other components as needed, as long as they do not impair the effects of the present invention. Examples of methods for blending these components include mixing using a Henschel mixer, V-blender, ribbon blender, tumbler blender, etc., and, as needed, melt-kneading using a kneader such as a single-screw extruder, multi-screw extruder, kneader, or Banbury mixer. There are no particular limitations on the blending method, as long as the effects of the present invention are not impaired.

[0069] 1-4. Film manufacturing The film forming machine used to produce the film is a machine that forms a film by melt extrusion through a T-die, and examples thereof include known T-die film processing machines and known T-die extrusion lamination machines, with a T-die film processing machine being preferred. Preferred film-forming conditions for production using a T-die film processing machine include a resin temperature of 160 to 260°C and a cooling roll temperature of 20 to 80°C. The resulting T-die film may be a single-layer film or a multilayer film containing at least one layer made of the polypropylene resin composition for unstretched films. The application of the film is not particularly limited, and it can be used, for example, as a film for packaging food such as bread and vegetables, as a film for packaging clothing such as shirts, as a film for packaging industrial parts, etc. Furthermore, the film can also be used as a sealant material for films laminated to films such as cellophane, paper, textiles, paperboard, aluminum foil, polyamide resins such as nylon 6 and nylon 66, polyester resins such as polyethylene terephthalate and polybutylene terephthalate, oriented polypropylene, and non-oriented polypropylene by known techniques such as lamination methods such as dry lamination and sand lamination.

[0070] The method for obtaining polypropylene resin (X) is not particularly limited, and it can be produced by the method described above in "1-1-6. Production method of polypropylene resin (X)". The method for obtaining polypropylene resin (Y) is not particularly limited, and it can be produced by the method described above in "1-2-2. Production method of polypropylene resin (Y)". The method for mixing the polypropylene resin (X) and the polypropylene resin (Y) is not particularly limited, and examples thereof include mixing using a Henschel mixer, a V blender, a ribbon blender, a tumbler blender, or the like. The method for melt-kneading the polypropylene resin (X) and the polypropylene resin (Y) is not particularly limited, and examples thereof include melt-kneading methods using a kneader such as a single-screw extruder, a multi-screw extruder, a kneader, or a Banbury mixer. The ratio of polypropylene resin (X) to polypropylene resin (Y) may be the ratio described above in "1-3-1. Ratio of polypropylene resin (X) to polypropylene resin (Y)."

[0071] 2. Film The film of the present invention is an unstretched film comprising at least one layer made of the polypropylene resin composition for unstretched films of the present invention, wherein the polypropylene resin composition layer comprises 1 to 30 mass% of a polypropylene resin (X) satisfying the above properties (X-1) to (X-6) and 99 to 70 mass% of a polypropylene resin (Y) satisfying the above properties (Y-1) to (Y-5) (wherein the total amount of the polypropylene resin (X) and the polypropylene resin (Y) is 100 mass%), and 0.005 to 0.7 parts by weight of a crystal nucleating agent (A) per 100 parts by weight of the total content of the polypropylene resin (X) and the polypropylene resin (Y).

[0072] The ratio of polypropylene resin (X) to polypropylene resin (Y) may be the ratio described above in "1-3-1. Ratio of polypropylene resin (X) to polypropylene resin (Y)."

[0073] One aspect of the present invention is an unstretched film made from the polypropylene resin composition for an unstretched film of the present invention (hereinafter also referred to as "unstretched film of the present invention"). Another embodiment of the present invention is a film using the non-stretched film of the present invention as a heat seal layer.

[0074] Another embodiment of the present invention is a multilayer film comprising a heat seal layer made of the non-stretched film of the present invention.

[0075] Another aspect of the present invention is a food packaging film comprising the non-stretched film of the present invention.

[0076] The method for producing the non-stretched film of the present invention is not particularly limited, and the film can be produced by the method described above in "1-4. Production of film." [Example]

[0077] The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. The evaluation methods and resins used in the examples and comparative examples are as follows.

[0078] 1. Evaluation Method Evaluations were carried out at 20 to 25°C unless otherwise specified. (1) MFR The MFR was measured in accordance with JIS K7210:2014, and the unit of MFR is g / 10 min. (2) Mw / Mn and Mz / Mw Mw / Mn and Mz / Mw were determined by GPC measurement according to the method described above. (3)MT MT was measured using a Capillograph 1B manufactured by Toyo Seiki Seisakusho, according to the method described above. (4) g' g' was determined by GPC equipped with a differential refractometer (RI), a viscosity detector (Viscometer), and a light scattering detector (MALLS) as detectors. (5) mm fraction The mm fraction is calculated according to the method described above. 13 The carbon content was determined by C-NMR. A more specific method for determining the mm fraction is described in detail in paragraphs

[0053] to

[0065] of JP 2009-275207 A, and this method was also followed in the present invention. The mm fraction is expressed in %. (6) Melting point The melting point was measured using a differential scanning calorimeter (DSC) by first raising the temperature to 200°C, leaving it for 5 minutes, then lowering the temperature to 40°C at a rate of 10°C / min, and then measuring again at a rate of 10°C / min. The melting point was determined as the temperature at the top of the endothermic peak. The melting point is measured in °C.

[0079] (7) HAZE Haze was measured in accordance with JIS K7136:2000. The smaller the haze value, the better the transparency. Haze is measured in %. (8) Internal haze In accordance with JIS K 7136:2000, two standard glass pieces were filled with oil, a film was inserted between them, and the internal haze was measured. A low internal haze indicates high transparency. The unit of internal haze is %.

[0080] (9) Young's modulus The Young's modulus was measured in accordance with JIS K7127:1989, where the tensile modulus (Young's modulus) in the machine direction (MD) of the film was measured under the following conditions. The unit of Young's modulus is MPa. Sample shape: Strip Sample length: 150mm Sample width: 15mm Chuck distance: 100mm Crosshead speed: 1mm / min (10) Heat sealability Heat sealability was measured in accordance with JIS K1707:2019. The unit of heat sealability is °C. Using a 10 mm x 200 mm heat seal bar, the resulting film was heat-sealed perpendicular to the melt extrusion direction (MD) at 110 °C to 160 °C in 5 °C increments, with a pressure of 0.2 MPa and a heat seal time of 1 second, so that the heat seal layers were heat-sealed together. Next, samples were cut out to a 15 mm wide heat-sealed section and peeled using a tensile tester at room temperature at a tensile speed of 500 mm / min using the T-peel method. The heat seal strength (unit: N / 15 mm width) was measured. The relationship between heat seal temperature and maximum heat seal strength was plotted, and the slope of the resulting curve was determined. The heat sealability (the temperature at which the heat seal strength reached 3.0 N / 15 mm width) was calculated.

[0081] 2.Materials used (1) Polypropylene resin (X) As the polypropylene resin (X1), a propylene homopolymer having a long chain branched structure polymerized by a metallocene catalyst using a macromer copolymerization method, manufactured by Japan Polypropylene Corporation under the trade name "WAYMAX (registered trademark) MFX3", was used. The MFR, GPC, MT, g', 13 C-NMR and melting point evaluation were performed. The evaluation results are shown in Table 1. Polypropylene resin (X1) satisfies requirement (X-3), log(MT)≧−0.9×log(MFR)+0.7 (Equation 1). As the polypropylene resin (X2), a propylene homopolymer having a long-chain branched structure polymerized with a metallocene catalyst using a macromer copolymerization method, manufactured by Japan Polypropylene Corporation under the trade name "WAYMAX (registered trademark) MFX6", was used. The MFR, GPC, MT, g', 13 C-NMR and melting point evaluation were performed. The evaluation results are shown in Table 1. Polypropylene resin (X2) satisfies requirement (X-3), log(MT)≧-0.9×log(MFR)+0.7 (Equation 1).

[0082] [Table 1]

[0083] (2) Polypropylene resin (Y) The polypropylene resin (Y1) used was Wintec (registered trademark) WFX4M (ethylene content: 3.1% by mass, melting peak temperature Tm: 125°C, MFR: 7g / 10 min, melt tension MT: 0.5g), a propylene-ethylene copolymer polymerized using a metallocene catalyst, manufactured by Japan Polypropylene Corporation. The polypropylene resin (Y1) satisfies requirement (Y-5) of g' being 0.95 or more and 1.0 or less. The polypropylene resin (Y2) used was Novatec PP (registered trademark) FX4GF (ethylene content: 2.8% by mass, 1-butene content: 8.0% by mass, melting peak temperature Tm: 126°C, MFR: 5 g / 10 min, molecular weight distribution Mw / Mn: 4.9), a propylene-ethylene-1-butene terpolymer polymerized using a Ziegler-Natta catalyst, manufactured by Japan Polypropylene Corporation. The polypropylene resin (Y3) used was Novatec PP (registered trademark) FW4BA manufactured by Japan Polypropylene Corporation, a propylene-ethylene-1-butene terpolymer polymerized using a Ziegler-Natta catalyst (ethylene content: 2.8% by mass, 1-butene content: 2.8% by mass, melting peak temperature Tm: 138°C, MFR: 7 g / 10 min, molecular weight distribution Mw / Mn: 4.9). As the polypropylene resin (Y4), Novatec PP (registered trademark) FB3HBT (melting peak temperature Tm: 164°C, MFR: 10 g / 10 min, molecular weight distribution Mw / Mn: 5.0) manufactured by Japan Polypropylene Corporation, which is a propylene homopolymer polymerized using a Ziegler-Natta catalyst, was used.

[0084] (3) Nucleating agent (A) Nucleating agent (A1): 1,3,5-tris(2,2-dimethylpropanamido)benzene (trade name: Irgaclear XT 386) manufactured by BASF Japan Ltd. Nucleating agent (A2): sodium 2,4,8,10-tetra-tert-butyl-6-oxo-12H-dibenzo[d,g][1,3,2]dioxaphosphocin-6-olate (trade name: Adeka STAB NA-11) manufactured by ADEKA Corporation

[0085] [Examples 1 to 6, Comparative Example 3] Polypropylene resin (X), polypropylene resin (Y), and crystal nucleating agent (A) were mixed in the ratios shown in Table 2 using a Henschel mixer, and then the mixture was melt-extruded at 220°C using an extruder with a screw diameter of 50 mmΦ to form pellets. The obtained pellets were introduced into a single-layer T-die (die width 330 mm, die lip opening 0.8 mm) using a 35 mm diameter extruder set to a resin temperature of 220°C, and melt-extruded.The pellets were then cooled and solidified using a #200 matte surface-treated cooling roll adjusted to 30°C and rotating at 20 m / min, yielding a single-layer unstretched film 30 μm thick. The physical properties of the resulting pellets and film were measured according to the above-mentioned methods. Table 2 shows the evaluation results.

[0086] [Comparative Examples 1 and 2] Polypropylene resin (X) and polypropylene resin (Y) were mixed in the ratios shown in Table 2 using a Henschel mixer, and then melt-extruded at 220°C using an extruder with a screw diameter of 50 mmΦ to form pellets. The obtained pellets were introduced into a single-layer T-die (die width 330 mm, die lip opening 0.8 mm) using a 35 mm diameter extruder set to a resin temperature of 220°C, and melt-extruded.The pellets were then cooled and solidified using a #200 matte surface-treated cooling roll adjusted to 30°C and rotating at 20 m / min, yielding a single-layer unstretched film 30 μm thick. The physical properties of the resulting pellets and film were measured according to the above-mentioned methods. Table 2 shows the evaluation results.

[0087] [Table 2]

[0088] The films of Examples 1 to 6 had an excellent balance of rigidity and haze without impairing the good heat sealability as a sealant material, because the polypropylene resin (X) and the polypropylene resin (Y) contained in the polypropylene resin composition satisfied all of the specific physical properties of the present invention. In Comparative Examples 1 and 2, the polypropylene resin (X) and the nucleating agent (A1) or (A2) were not contained, and therefore the balance between heat sealability and rigidity was poor, and the haze was also poor. In Comparative Example 3, the polypropylene resin composition for a non-oriented film of the present invention was not contained, and therefore the balance between heat sealability and rigidity was poor, and the haze was also high.

Claims

1. A polypropylene resin composition for use in an unstretched film, comprising 1 to 30 mass% of a polypropylene resin (X) that satisfies the following properties (X-1) to (X-6), and 99 to 70 mass% of a polypropylene resin (Y) that satisfies the following properties (Y-1) to (Y-5) (wherein the total amount of the polypropylene resin (X) and the polypropylene resin (Y) is 100 mass%), and comprising 0.005 to 0.7 parts by weight of a crystal nucleating agent (A) per 100 parts by weight of the total content of the polypropylene resin (X) and the polypropylene resin (Y). (X-1) MFR (230°C, load 2.16 kgf) is 0.1 to 30.0 g / 10 min. (X-2) The ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) obtained by GPC is 3.0 to 10.

0. (X-3) The melt tension (MT) (unit: g) measured at 230°C satisfies the relationship of the following (Equation 1) or (Equation 2). log(MT)≧−0.9×log(MFR)+0.7 (Formula 1) MT≧15 (Formula 2) (X-4) Branching index g' (M ａｂｓ ) is 0.30 or more and less than 0.

95. (X-5) １３ The mm fraction of propylene unit triads determined by C-NMR is 95% or more. (X-6) Polymerized with a metallocene catalyst (Y-1) The ethylene content is in the range of 1.0 to 6.0% by mass. (Y-2) MFR (230°C, load 2.16 kgf) is 1 to 30 g / 10 min. (Y-3) The ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) obtained by GPC is 2.0 to 4.

0. (Y-4) Polymerized with a metallocene catalyst (Y-5) Branching index g' (M ａｂｓ ) is 0.95 or more and 1.0 or less.

2. 2. The polypropylene resin composition for use in a non-oriented film according to claim 1, wherein the polypropylene resin (Y) is a propylene-ethylene copolymer.

3. An unstretched film comprising the polypropylene resin composition for unstretched films according to claim 1 or 2.

4. A film using the non-oriented film according to claim 3 as a heat seal layer.

5. A multilayer film comprising a heat seal layer made of the non-oriented film according to claim 3.

6. A food packaging film comprising the unstretched film according to claim 3.

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