JP2019081856A - Resin composition and porous film - Google Patents

Abstract

To provide a resin composition capable of producing a porous film excellent in air permeability and piercing strength.SOLUTION: The resin composition includes a polyolefin resin and cellulose. In the resin composition, the cellulose is cellulose having an average major axis of 5 μm or less; the cellulose content is 0.05 to 15.0 pts.mass based on 100 pts.mass of the total of the polyolefin resin and the cellulose; and the isothermal crystallization half time at a temperature higher than an extrapolated crystallization onset temperature obtained by differential scanning calorimeter (DSC) by 4°C is 15 minutes or less.SELECTED DRAWING: None

Description

  The present invention relates to a resin composition and a porous film.

Polyolefins are resins used in a wide range of fields such as general packaging materials, containers, pipes, separators for batteries, parts of automobiles, and the like. Among them, a polyolefin film having porosity has a separation function of liquid and solid or gas and solid, or a transmission function of minute substances such as ions, and is used as a filter and a battery separator (for example, patent documents 1).
Above all, as the demand for electric vehicles and notebook computers increases, the production amount of lithium ion batteries increases, and for example, the use amount of polyolefin for battery separator application as disclosed in Patent Document 2 increases.

JP 2000-317280 JP-A-2015-134900 JP 2008-81513 Patent No. 3381538 Reissue Patent 2014/017335 JP, 2013-56958, A JP 2014-234472

  However, at present, there is also room for improvement in battery separators. Although the manufacturing method of a microporous film is disclosed by patent document 3 as a porous film for battery separators, addition and removal of a solvent are needed and there exists a problem that a process becomes complexity. Moreover, although extending | stretching which does not use a solvent is disclosed by patent document 4, the microporous film which has sufficient physical property is not obtained.

  In addition, the porous film is required to have many fine holes open in any of filter application and battery separator application. The large number of fine holes, for example, improves the efficiency of filtration in applications such as filters. In addition, as the battery separator application, the number of moving ions increases, which contributes to the improvement of battery performance. As an indicator of the number of fine holes in this film, there is air permeability, which is measured by a Gurley air permeability meter. However, if the fine holes are increased to improve the air permeability, the penetration strength tends to decrease. It is difficult in the prior art to improve both the air permeability and the penetration strength.

  Further, Patent Documents 5 to 7 disclose that a microporous film is produced by adding modified cellulose. However, modified cellulose does not improve the crystallization rate and the degree of crystallinity, and is not known to affect the air permeability and puncture strength of a porous film.

  This invention is made in view of the said problem, and it aims at providing the resin composition which can manufacture the porous film which is excellent in air permeability and puncture strength.

  In the present invention, as a result of intensive studies to achieve the above-mentioned problems in order to solve the above problems, a resin composition in which fine cellulose is added to a polyolefin resin is in a composition in which the cellulose contains the polyolefin resin uniformly. The inventors have found that a porous film which is dispersed and is excellent in air permeability and puncture strength can be obtained, and the present invention has been completed.

That is, the present invention relates to the following.
[1]
A resin composition comprising a polyolefin resin and cellulose,
The cellulose is cellulose having an average major axis of 5 μm or less,
The content of the cellulose is 0.05 to 15.0 parts by mass with respect to a total of 100 parts by mass of the polyolefin resin and the cellulose,
The resin composition whose 1/2 isothermal crystallization time in temperature higher 4 degreeC than the extrapolation crystallization start temperature of a differential scanning calorimeter (DSC) is 15 minutes or less.
[2]
The resin composition according to [1], wherein the cellulose is crystalline cellulose.
[3]
The ethylene alone, wherein the polyolefin resin has an MFR (measured at 190 ° C. under a load of 2.16 kg according to JIS K 7210) of 0.1 to 2.0 g / 10 min and a density of 950 to 970 kg / m ³ A polymer and / or an ethylene copolymer,
The temperature of the crystallization peak during the temperature lowering process of DSC is 112 ° C. or higher,
Endothermic enthalpy in heating process (△ H ₂₎ is not more than 190J / g or more 220 J / g of resin terms, [1] or the resin composition according to [2].
[4]
The polyolefin resin is a polypropylene homopolymer and / or a polypropylene copolymer having an MFR (measured at 230 ° C. under a load of 2.16 kg according to JIS K 7210-1) of 0.1 to 60 g / 10 min. Yes,
The temperature of the crystallization peak in the temperature lowering process of DSC is 120 ° C. or higher,
Endothermic enthalpy in heating process (△ H ₂₎ is not more than 115J / g or more 140 J / g of resin terms, [1] or the resin composition according to [2].
[5]
The resin composition in any one of [1]-[4] containing the oil and / or wax which have a polyoxyethylene chain in a molecule | numerator.
[6]
The porous film produced from the resin composition described in any one of [1]-[5].

  According to the present invention, a resin composition containing a polyolefin resin, which is a raw material of a porous film excellent in air permeability and puncture strength, a porous film obtained from the resin composition, a method for producing the same, and a battery separator Can be provided.

  Hereinafter, a mode for carrying out the present invention (hereinafter referred to as "the present embodiment") will be specifically described, but the present invention is not limited to this, and various modifications can be made within the scope of the present invention. Variations are possible.

The resin composition of the present embodiment contains a polyolefin resin and cellulose.
The said cellulose is a cellulose of 5 micrometers or less of average major axis, and the addition amount is 0.05-15.0 mass parts.
In the resin composition of the present embodiment, the 1⁄2 isothermal crystallization time at a temperature 4 ° C. higher than the extrapolation crystallization start temperature of the differential scanning calorimeter (DSC) is 15 minutes or less.

[Polyolefin resin]
The resin composition of the present embodiment uses a polyolefin resin as a main raw material. When using polyolefin resin as the main raw material, the total of polyolefin resin and cellulose is 100 parts by mass, usually 85.00 to 99.95 parts by mass, preferably 87.00 to 99.93 parts by mass, more preferably It indicates that it is 88.00 to 99.92.
Examples of the polyolefin resin include polyethylene resin, polypropylene resin, polybutene resin, poly (4-methyl-1-pentene) resin, and copolymers of these. The present invention is effective with any of these polyolefin resins, and may be one or a mixture of two or more.
Moreover, when polyolefin resin is a copolymer of the above-mentioned resin, it may be a random polymer and may be a block polymer.

(Polyethylene resin)
Among the above-mentioned polyolefin resins, one preferable resin is ethylene homopolymer and / or ethylene copolymer.
The ethylene homopolymer and the ethylene copolymer preferably have a density of 0.1 to 2.0 g / 10 min, and a density of MFR (performed at 190 ° C. under a load of 2.16 kg according to JIS K 7210). Ethylene homopolymer and / or ethylene copolymer having a weight of 950 to 970 kg / m ³ , more preferably having an MFR of 0.12 to 1.0 g / 10 min, and a density of 955 to 968 kg / m ³ It is an ethylene homopolymer and / or ethylene copolymer which is m ³ , more preferably, the MFR is 0.15 to 0.40 g / 10 min, and the density is 960 to 967 kg / m ³ Ethylene homopolymer and / or ethylene copolymer.

The ethylene copolymer is a copolymer of ethylene and an olefin copolymerizable with the ethylene (hereinafter, also referred to as a comonomer).
The olefin copolymerizable with ethylene is not particularly limited, and specifically, an α-olefin having 3 to 15 carbon atoms, a cyclic olefin having 3 to 15 carbon atoms, a formula CH ₂ = CHR ¹ (where R is ¹ is an aryl group having a carbon number of 6 to 12.) and at least one comonomer selected from the group consisting of a linear, branched or cyclic diene having a carbon number of 3 to 15 Be Among these, preferred is an α-olefin having 3 to 15 carbon atoms.
The α-olefin is not particularly limited, and examples thereof include propylene, 1-butene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1- Dodecene, 1-tridecene, 1-tetradecene and the like can be mentioned.
When the ethylene polymer contains a comonomer, the content of comonomer units in the ethylene polymer is preferably 2 mol% or less, more preferably 1.5 mol% or less, and still more preferably 1 mol% or less It is. The lower limit of the comonomer content is not particularly limited as long as it is greater than 0 mol%.
The ethylene copolymer may be a random copolymer or a block copolymer.

(Polypropylene resin)
Among the above-mentioned polyolefin resins, one preferred resin is a polypropylene homopolymer and / or a polypropylene copolymer.
The polypropylene resin is preferably a polypropylene resin having an MFR (measured at 230 ° C. under a load of 2.16 kg according to JIS K 7210-1) of 0.1 to 60 g / 10 min, more preferably an MFR It is a polypropylene resin which is 0.2-35 g / 10 minutes, More preferably, it is a polypropylene resin whose MFR is 0.3-20 g / 10 minutes.

The polypropylene copolymer is a copolymer of polypropylene and a copolymerizable olefin (hereinafter, also referred to as a comonomer).
The olefin copolymerizable with polypropylene is not particularly limited, and specifically, α-olefins having 2 to 15 carbon atoms, cyclic olefins having 3 to 15 carbon atoms, a formula CH ₂ 2CHR ¹ (wherein ¹ is an aryl group having a carbon number of 6 to 12.) and at least one comonomer selected from the group consisting of linear, branched or cyclic dienes having a carbon number of 2 to 15 Be Among these, preferred are α-olefins having 2 to 15 carbon atoms.
The α-olefin is not particularly limited, and examples thereof include ethylene, 1-butene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1- Dodecene, 1-tridecene, 1-tetradecene and the like can be mentioned.
When the polypropylene polymer contains a comonomer, the content of comonomer units in the polypropylene polymer is preferably 5 mol% or less, more preferably 2 mol% or less, and still more preferably 1 mol% or less. . The lower limit of the comonomer content is not particularly limited as long as it is greater than 0 mol%.
The polypropylene copolymer may be a random copolymer or a block copolymer.

The polyolefin resin in the present embodiment may be prepared from monomers by a known polymerization method, or commercially available resins may be used.
Polyethylene homopolymers and polyethylene copolymers, as described above, and polypropylene homopolymers and polypropylene copolymers are also available from commercial products.

[cellulose]
The resin composition of the present embodiment contains 0.05 to 15.0 parts by mass of cellulose having an average major axis of 5 μm or less in the composition.
The major axis of cellulose in the present embodiment refers to the longest diameter in a projection view of particles, and the average major axis is an average value of the major axes of two or more particles.
By including cellulose having an average major axis of more than 5 μm in the resin composition, the tensile strength at break tends to decrease after the film, sheet, parts and the like are formed. The reason is considered that when the product is stressed, large particles break off from the end of the particles. When the particles are 5 μm or less, polyolefin molecules tend to be entangled with cellulose, and the breaking strength of films, sheets, parts and the like tends to be excellent.
In addition, when the average major axis of the cellulose particles is more than 5 μm, visible light is scattered, and the visible light transmittance tends to be significantly reduced.
In addition, the cellulose in the present embodiment is considered to improve the crystallization rate and the degree of crystallization by acting as nuclei at the time of crystallization of the polyolefin. The improvement of the crystallization rate leads to an increase in the number of fine crystals. In the porosifying step, the formation of holes starting from the fine crystals leads to the generation of a large number of relatively small holes. Further, the improvement of the degree of crystallinity means that the film becomes hard, which leads to the improvement of the piercing strength.

The average major axis of cellulose in the present embodiment is preferably 3 μm or less, more preferably 1 μm or less.
The lower limit of the average major axis is not particularly limited as long as it is larger than 0 μm, preferably 0.010 μm or more, and more preferably 0.050 μm or more.

The cellulose having an average major axis of 5 μm or less may be any of those generally called cellulose nanofibers, cellulose nanocrystals, and cellulose nanowhiskers, and is preferably cellulose nanocrystals.
The amount of cellulose added is preferably 0.07 to 13.0 parts by mass, more preferably 0.08 to 12.0 parts by mass.
When the addition amount is less than 0.05 parts by mass, improvement in crystallization rate and crystallinity tends not to be observed. On the other hand, if it exceeds 15.0 parts by mass, re-aggregation of the cellulose particles may occur during mixing with the resin, and uniform dispersion tends to be difficult.

  The “cellulose” in the present embodiment is a naturally occurring water-insoluble fibrous material containing cellulose. Examples of the cellulose raw material include wood, bamboo, wheat straw, rice straw, cotton, ramie, bagasse, kenaf, beet, sea squirt, bacterial cellulose and the like. As the raw material, one of these natural cellulose-based materials may be used, or a mixture of two or more may be used.

The average major axis of cellulose is measured by the following method.
First, 5 to 10% by mass of cellulose powder is dissolved in pure water with respect to the weight of water, and after sufficiently dispersing cellulose using a biomixer (BM-4) manufactured by Nippon Seiki, 0.1 to 0.5% by mass Dilute with pure water to a concentration of
After that, cast on mica and air-dried ones, and observe them with a high resolution scanning microscope (SEM) or an atomic force microscope (AFM), and image analysis of 100 to 150 particle images obtained by the observation. Calculate the average major axis by calculation using software.
Moreover, when measuring the average major axis of the cellulose mixed in resin, it measures as follows.
The polyolefin resin composition containing cellulose is dissolved in o-dichlorobenzene or trichlorobenzene and heated to 140 ° C. After stirring until completely dissolved, hot filtration is performed to separate the cellulose and the resin. The separated cellulose is dispersed in pure water in the same manner as above, air-dried, and observed with a high resolution scanning microscope (SEM) or an atomic force microscope (AFM), and 100 to 150 particle images obtained by the observation The average major axis is calculated by calculating using the image analysis software.
The average major axis of cellulose can be measured specifically by the method described in the examples.

In the cellulose in the present embodiment, the ratio (L / D) of the major axis (L) to the minor axis (D) is defined and measured in the same manner as in the major axis measurement.
The ratio (L / D) is preferably less than 20, more preferably 15 or less, still more preferably 10 or less, still more preferably 5 or less, from the viewpoint of suspension stability. Preferably it is less than 5, especially preferably 4 or less.

The average degree of polymerization of cellulose in the present embodiment is preferably 500 or less. When the average degree of polymerization is 500 or less, in the step of complexing with an organic component, cellulose is easily subjected to physical treatment such as stirring, grinding, grinding and the like, and complexation is easily promoted. The average degree of polymerization of cellulose is preferably 400 or less, more preferably 350 or less, still more preferably 300 or less, still more preferably 250 or less, particularly preferably 200 or less. The lower limit of the average degree of polymerization is not particularly limited because the smaller the average degree of polymerization is, the easier the control of the formation of the compound is.
The average degree of polymerization can be measured by the reduction specific viscosity method using a copper ethylenediamine solution as defined in the crystalline cellulose confirmation test (3) of “14th Amended Japanese Pharmacopoeia” (issued by Yodogawa Shoten), and specifically described in the Examples It can be measured by the method of

  As a method of controlling the average degree of polymerization of cellulose, the method etc. of carrying out the hydrolysis process of the raw material of the cellulose mentioned above are mentioned, for example. By the hydrolysis treatment, depolymerization of the amorphous cellulose inside the cellulose fiber proceeds, and the average degree of polymerization decreases. At the same time, impurities such as hemicellulose and lignin are also removed by the hydrolysis treatment in addition to the above-mentioned amorphous cellulose, so that the inside of the fiber is made porous. As a result, in the step of applying mechanical shear force to the cellulose and the organic component, such as during the kneading step, the cellulose is easily subjected to mechanical processing, and the cellulose is easily refined. As a result, the surface area of the cellulose is increased, and control of complexation with the organic component is facilitated.

The method of hydrolysis is not particularly limited, and examples thereof include acid hydrolysis, thermal decomposition, steam explosion, microwave decomposition and the like. These methods may be used alone or in combination of two or more. In acid hydrolysis, an average degree of polymerization can be easily controlled by adding an appropriate amount of a protonic acid, a carboxylic acid, a Lewis acid, a heteropolyacid or the like in a state where cellulose is dispersed in an aqueous medium, and heating while stirring. The reaction conditions such as temperature, pressure and time in this case vary depending on the cellulose species, cellulose concentration, acid species and acid concentration, but are suitably adjusted so that the target average polymerization degree is achieved.
In a specific method of hydrolysis, a cellulose is treated under a pressure of 100 ° C. or more and 10 minutes or more using a mineral acid aqueous solution of 2% by mass or less. In the case of processing under these conditions, catalyst components such as acids penetrate into the interior of the cellulose fiber to promote hydrolysis, reducing the amount of catalyst component used, and as a result, subsequent purification becomes easy.

The cellulose in the resin composition of the present embodiment is preferably crystalline cellulose, contains cellulose I-type crystals, and more preferably has a crystallinity of 10% or more. When the degree of crystallinity is 10% or more, the mechanical properties (strength and dimensional stability) of the cellulose particles themselves are enhanced, so when dispersed in a resin, the strength and dimensional stability of the resin compound tend to be increased. . The degree of crystallinity is more preferably 30% or more, further preferably 50% or more, and still more preferably 70% or more. The upper limit of the degree of crystallinity is preferably, but not limited to, 90% or less.
The crystalline cellulose in this embodiment is selected from the group consisting of the above-mentioned cellulose raw materials, for example, wood, bamboo, wheat straw, rice straw, cotton, ramie, bagasse, kenaf, beet, sea squirt, and bacterial cellulose. It refers to the partially depolymerized and purified species with acid.

The degree of crystallinity can be determined from the diffraction pattern (2θ / deg .: 10 to 30) when cellulose is measured by wide-angle X-ray diffraction, according to the following formula by the Segal method.
Crystallinity (%) = ((diffraction intensity attributable to (200) plane at (2θ / deg. = 22.5))-(diffraction intensity attributable to amorphous at 2θ / deg. = 18) / (2θ Diffraction intensity attributable to the (200) plane of / deg. = 22.5) × 100

  The cellulose in the present embodiment is preferably obtained by a method of preparing an aqueous slurry in which cellulose is uniformly dispersed in the process, and therefore, it is preferable that the cellulose contains colloidal cellulose. As the content of the colloidal cellulose is higher, when the cellulose is dispersed in the resin composition, the dispersion proceeds and a network having a high surface area can be formed, so the strength of the resin tends to be improved. The content of colloidal cellulose in the cellulose is preferably 50% by mass or more, more preferably 60% by mass or more, still more preferably 70% by mass or more, still more preferably 80% by mass or more . The upper limit of the content of colloidal cellulose is not particularly limited, and the theoretical upper limit is 100% by mass.

The content of colloidal cellulose can be measured by the following method. The cellulose is mixed at a solid content of 40% by mass in a planetary mixer (5DM-03-R manufactured by Shinagawa Kogyosho, with a stirring blade of hook type) at 126 rpm under normal pressure at room temperature for 30 minutes, and A solid content is a pure water suspension at a concentration of 0.5% by mass, and a high shear homogenizer (manufactured by Nippon Seiki Co., Ltd., trade name "Excel Auto Homogenizer ED-7" Processing conditions: rotational speed 15,000 rpm x 5 minutes Dispersed, and centrifuged (manufactured by Kubota Shoji Co., Ltd., trade name “6800 type centrifuge”, rotor type RA-400 type, treatment conditions: supernatant for 10 minutes at a centrifugal force of 39,200 m ² / s is collected, Furthermore, this supernatant, 116000m ² / s centrifuging 45 min.) and measures the solids remaining supernatant after centrifugation at absolute dry method, calculates the mass percentage That.

The smaller the particle diameter, the more preferable the cellulose in the present embodiment. As the particle size is smaller, when a cellulose preparation using the cellulose is dispersed in a resin, the dispersion proceeds and a network having a high surface area can be formed, so the strength and dimensional stability of the resin tend to be improved. The particle size of the cellulose is preferably 1.0 μm or less, more preferably 0.7 μm or less, still more preferably 0.5 μm or less, and still more preferably 0.3 μm or less. The lower limit of the particle size is not particularly limited, but is practically 0.05 μm or more.
Since the major axis measurement with a microscope is measurement in a dry state, the particle size of cellulose in water is separately specified. The particle size of cellulose in water is preferably 0.05 μm to 1.00 μm, more preferably 0.08 μm to 0.90 μm, and still more preferably 0.10 μm to 0.80 μm.

The particle size of cellulose can be measured by the following method. The cellulose is mixed at a solid content of 40% by mass in a planetary mixer (5DM-03-R manufactured by Shinagawa Kogyosho, with a stirring blade of hook type) at 126 rpm under normal pressure at room temperature for 30 minutes, then 0 .5% by weight of pure water suspension, dispersed by high shear homogenizer (manufactured by Nippon Seiki Co., Ltd., trade name "Excel Auto Homogenizer ED-7" treatment condition: rotation speed 15,000 rpm x 5 minutes) , Centrifugation (manufactured by Kubota Shoji Co., Ltd., trade name "6800 type centrifuge", rotor type RA-400 type, treatment condition: Supernatant collected by centrifugation at 39,200 m ² / s of centrifugal force for 10 minutes, and further, this supernatant And centrifuge at 116000 m ² / s for 45 minutes) and collect supernatant after centrifugation. A volume frequency particle size obtained by a laser diffraction / scattering particle size distribution analyzer (trade name “LA-910” manufactured by Horiba, Ltd., product name: “LA-910”, ultrasonication 1 minute, refractive index 1.20) using this supernatant. The integrated 50% particle size (volume average particle size) in the distribution is measured.

The crystallization rate, the temperature of the crystallization peak and the endothermic enthalpy in the resin composition of the present embodiment can be measured by DSC, and specifically can be measured by the method described in the examples.
For example, a DSC 8000 manufactured by PERKIN ELMER can be used as a DSC measurement apparatus. The measurement is carried out at a heating rate of 10 ° C./minute from 50 ° C. to a temperature at which the resin completely melts. This is 1st. Call it Heating. The maximum temperature can be appropriately selected according to the melting point of the polyolefin resin to be used, but in the case of a polyethylene resin, generally 180 ° C., and in the case of a polypropylene resin, generally 200 ° C. .
Next, the temperature is lowered from the temperature at which the resin melted to 50 ° C. at a rate of 10 ° C./min. This is 1st. The peak is referred to as Coolin, and the extrapolated crystallization start temperature and crystallization temperature of the resin are read from the curve measured in this process. Finally, the measurement is carried out at a temperature rising rate of 10 ° C./min from 50 ° C. to the melting temperature of the resin. This is 2nd. Call it Heating. The endothermic enthalpy is read from the curve measured in this process.

The 1⁄2 isothermal crystallization time in the present embodiment is maintained at a constant temperature 4 ° C. higher than the extrapolation crystallization start temperature determined above for 40 minutes, and the exothermic curve measured at this time is peaked It is defined as time.
The 1⁄2 isothermal crystallization time at a temperature 4 ° C. higher than the extrapolation crystallization start temperature of DSC is 15 minutes or less, preferably 13 minutes or less. In the case of polyethylene, the 1/2 isothermal crystallization time is more preferably 12 minutes or less. In the case of polypropylene, the 1⁄2 isothermal crystallization time is more preferably 10 minutes or less, still more preferably 5 minutes or less, still more preferably 3 minutes or less.

In order to control the 1/2 isothermal crystallization time, for example, blending of cellulose having an average major diameter of 5 μm or less as described above, and the like can be mentioned.
In addition, by dispersing fine cellulose having an average major axis of 5 μm or less in the resin without aggregation, the 1⁄2 isothermal crystallization time can be made 15 minutes or less. For that purpose, for example, it is preferable to sufficiently mix the resin powder and the slurry in which cellulose is finely dispersed in water with a biomixer or the like as described above, and further to knead it with a mixer, an extruder or the like. By preparing such a mixture, the 1⁄2 isothermal crystallization time can be controlled to 15 minutes or less.

The polyolefin resin of this embodiment has an MFR (measured at 190 ° C. under a load of 2.16 kg according to JIS K 7210) of 0.1 to 2.0 g / 10 min and a density of 950 to 970 kg / m ³ . When it is an ethylene homopolymer and / or an ethylene copolymer, the temperature of the crystallization peak in the temperature lowering process of DSC of the resin composition is preferably 112 ° C. or higher, more preferably from the viewpoint of heat resistance and strength. Is 117 ° C. or higher, more preferably 118.5 ° C. or higher.
The upper limit of the temperature of the crystallization peak is usually 125 ° C. or less, preferably 122 ° C. or less, more preferably 120 ° C. or less from the viewpoint of processability.
The temperature of the crystallization peak can be adjusted by the density of the polyolefin resin and the amount of added cellulose.

The polyolefin resin of this embodiment has an MFR (measured at 190 ° C. under a load of 2.16 kg according to JIS K 7210) of 0.1 to 2.0 g / 10 min and a density of 950 to 970 kg / m ³ . When it is an ethylene homopolymer and / or ethylene copolymer, the endothermic enthalpy (ΔH ₂ ) in the temperature rising process of the resin composition is usually 190 J / g or more and 220 J / g or less from the viewpoint of crystallinity And from the viewpoint of processability, preferably from 195 J / g to 215 J / g, and more preferably from 200 J / g to 210 J / g.
The endothermic enthalpy (ΔH ₂ ) can be adjusted by the addition amount of cellulose having an average major axis of 5 μm or less.

The polyolefin resin of this embodiment is a polypropylene homopolymer and / or a polypropylene co-polymer having an MFR (measured at 230 ° C. under a load of 2.16 kg according to JIS K 7210-1) of 0.1 to 60 g / 10 min. When it is a polymer, the temperature of the crystallization peak in the temperature lowering process of DSC of the resin composition is preferably 120 ° C. or higher, more preferably 125 ° C. or higher, and still more preferably 131 from the viewpoint of crystallinity. ° C or more.
The upper limit of the temperature of the crystallization peak is usually 140 ° C. or less, preferably 138 ° C. or less, more preferably 135 ° C. or less from the viewpoint of processability.
The temperature of the crystallization peak can be adjusted by the amount of added cellulose.

The polyolefin resin of this embodiment is a polypropylene homopolymer and / or a polypropylene co-polymer having an MFR (measured at 230 ° C. under a load of 2.16 kg according to JIS K 7210-1) of 0.1 to 60 g / 10 min. When it is a polymer, the endothermic enthalpy (ΔH ₂ ) in the temperature rising process of the resin composition is usually 115 J / g or more and 140 J / g or less from the viewpoint of crystallinity, and preferably from the viewpoint of processability. It is 122 J / g or more and 138 J / g or less, more preferably 125 J / g or more and 135 J / g or less.
The endothermic enthalpy (ΔH ₂ ) can be adjusted by the addition amount of cellulose having an average major axis of 5 μm or less.

(Method for producing resin composition)
The resin composition of the present embodiment can be obtained by a known method, and can be obtained, for example, by melt-kneading a polyolefin resin and cellulose with a plastomill mixer, a twin-screw extruder, or the like.
As described above, the resin composition of the present embodiment contains 0.05 to 15.0 parts by mass of cellulose having an average major axis of 5 μm or less. In order to obtain such a resin composition, it is preferable to previously mix a polyolefin resin and cellulose before the above-mentioned melt-kneading. Above all, it is preferable to mix a slurry in which cellulose is dispersed in water and a powdered polyolefin resin.

The method for obtaining a slurry in which cellulose is dispersed in water is not particularly limited, but it is preferable to use a mixer such as a homogenizer. Among homogenizers, a homogenizer that breaks particles by mechanical shear stress is preferable to an ultrasonic type homogenizer. Among them, a mixer called a biomixer, which breaks particles by shear stress generated in a narrow gap of a double cylinder, is preferable. The concentration of cellulose in the slurry is preferably 15% by mass or less, more preferably 10% by mass or less. The stirring time can be appropriately selected depending on the amount of cellulose to be used, and is preferably, for example, 1 hour or more.
After obtaining a slurry in which cellulose is dispersed in water by the above method, it can be mixed with a polyolefin resin powder. You may add oil etc. as needed. After sufficiently agitating the resin powder and the water slurry or oil, the resin powder in which fine cellulose is adhered to the surface can be obtained by slowly drying the resin powder and the boiling point or less using an oven.

The resin composition of the present embodiment may contain other addable components. Examples of other components that can be added include oils, greases and waxes. One of these may be used alone, or two or more of these may be used in combination.
The addition of oil, grease or wax to the resin composition tends to disperse the cellulose more uniformly.
As the oil, a compound having a functional group having affinity to both cellulose and a polyolefin resin is preferable, and examples of the above-mentioned compound include various esters and organic acids having a polyoxyethylene chain.

As the ester, a fatty acid ester is effective in improving the dispersibility, and examples thereof include glycerin monostearate, glycerin distearate, glycerin diacetomonolaurate, diglycerin stearate, polyglycerin polyricinolate and the like. In addition, ester compounds of rosin acid and various alcohols or polyoxyethylene chains also have the effect of improving dispersibility.
From the viewpoint of the dispersibility of cellulose, oils, greases and waxes having polyoxyethylene chains are more preferable. Such oils, greases and waxes having a polyoxyethylene chain, a compound in which a fatty acid and a polyoxyethylene chain are ester bonded, a compound in which a fatty acid is ester bonded to both ends of a polyoxyethylene chain, polyoxyethylene and ethylene glycol Examples of the compound in which the chain is ether-linked include a compound in which a fatty acid is ester-linked (polyoxyethylene-hardened castor oil) and the like, and polyoxyethylene-hardened castor oil is preferable.

  The blending amount of at least one selected from the group consisting of oil, grease and wax is preferably 0.01 to 5.0 parts by mass, more preferably 100 parts by mass in total of the polyolefin resin and the cellulose. Is 0.05 to 4.0 parts by mass, and more preferably 0.1 to 3.0 parts by mass.

The resin composition of this embodiment can be used especially as a raw material of a porous film. One of the preferable aspects of the present embodiment is a porous film produced from the resin composition of the present embodiment, that is, a porous film containing the resin composition of the present embodiment.
The porous film of the present embodiment is preferably a film having two or more fine holes (hereinafter, also referred to as a microporous film).
The microporous film can be obtained by a known method. For example, the target microporous film can be obtained by passing through a heat setting step, if necessary, through a film production step, a heat treatment step if necessary, and then a cold stretching step and a heat stretching step.

Specifically, the porous film of the present embodiment is manufactured by the following method.
(Film formation)
First, the resin composition of the present embodiment is supplied to an inflation molding apparatus to form a film at a temperature of 150 ° C. to 280 ° C., preferably 170 ° C. to 250 ° C.
The draw ratio after extrusion into a film as described above, that is, the film winding speed (unit: m / min) is the extrusion speed of the polyethylene resin composition (linear velocity in the flow direction of the molten resin passing through the die lip) The value divided by the unit: m / min) is preferably 10 to 500, more preferably 50 to 400, and still more preferably 100 to 300.
Also, the film winding speed is preferably about 2 to 400 m / min, more preferably 4 to 200 m / min. Setting the draw ratio in the above range is preferable from the viewpoint of improving the air permeability of the target microporous film.

(Heat treatment process)
It is preferable to perform heat processing (annealing) to the film formed into a film as mentioned above as needed. The method of annealing is not particularly limited. For example, a method of contacting the film on a heating roll, a method of exposing the film to a heating vapor phase before winding, a winding of the film on a core, a heating vapor phase or a heating liquid phase Methods of exposing to the inside, and methods of combining them are mentioned.
The conditions for the annealing are not particularly limited. For example, annealing at a heating temperature of 100 ° C. to 170 ° C. for 10 seconds to 100 hours is preferable. When the heating temperature is 100 ° C. or higher, the air permeability of the target microporous film is further improved. In addition, when the heating temperature is 170 ° C. or less, the films do not easily fuse even when annealing is performed in a state where the film is wound on the core. A more preferable heating temperature range is 110 ° C to 130 ° C.

(Cold stretch process)
Next, the cold stretching step will be described. After heat treatment as described above, cold stretching is performed in at least one direction by 1.05 to 2.0 times. The stretching temperature in the cold stretching step is preferably a temperature of −20 ° C. or more and less than 100 ° C., more preferably a temperature of 0 ° C. or more and 50 ° C. or less. By stretching at -20 ° C. or more, cracking of the microporous film tends to occur easily. Moreover, by stretching at less than 100 ° C., the gas permeability of the obtained microporous film tends to be better. Here, the stretching temperature is the surface temperature of the film in the cold stretching step.
The draw ratio of cold drawing in the cold drawing step is preferably 1.05 times or more and 2.0 times or less, and more preferably 1.2 times or more and 2.0 times or less. When the draw ratio in the cold drawing step is 1.05 or more, a microporous film with good air permeability tends to be obtained. In addition, when the draw ratio in the cold drawing step is 2.0 or less, a microporous film having a uniform film thickness tends to be obtained.
The cold drawing of the microporous film may be performed in at least one direction, and may be performed in two directions, but preferably, uniaxial drawing is performed only in the extrusion direction of the film.
In the present embodiment, in the cold stretching step, the microporous film is preferably uniaxially stretched 1.1 times to 2.0 times in the MD direction at a temperature of 0 ° C. or more and 50 ° C. or less.

(Thermal drawing process)
Next, the heat drawing process will be described. After cold drawing as described above, heat drawing is performed in at least one direction by 1.05 times or more and 5.0 times or less. The stretching temperature of the heat stretching is preferably 100 ° C. or more and 130 ° C. or less, more preferably 110 ° C. or more and 125 ° C. or less. By heat-stretching at 100 ° C. or more, the film is easily opened. By heat-stretching at 130 ° C. or less, the air permeability of the target microporous film becomes good. Here, the drawing temperature of the heat drawing is the surface temperature of the film in the heat drawing process.
The draw ratio of the heat drawing in the heat drawing step is preferably 1.05 times or more and 5.0 times or less, more preferably 1.1 times or more and 4.5 times or less, and still more preferably 1.5 times or more. It is less than 4.0 times. When the draw ratio in the heat drawing step is 1.05 or more, a microporous film with good air permeability tends to be obtained. Moreover, when the draw ratio in a heat | fever extending process is 5.0 times or less, it exists in the tendency for a microporous film with a uniform film thickness to be obtained.
The heat drawing is performed in at least one direction, and may be performed in two directions, but is preferably performed in the same direction as the drawing direction of cold drawing, and more preferably uniaxial drawing only in the same direction as the drawing direction of cold drawing. Do.
In the present embodiment, in the heat drawing process, the film cold drawn through the cold drawing process is uniaxially drawn 1.5 times to 5.0 times in the MD direction at a temperature of 100 ° C. or more and 130 ° C. or less. Is preferred.
In addition to the above-mentioned each extending process, the manufacturing method of the porous film of this embodiment may further perform an optional extending process.

(Heat setting process)
It is preferable that the manufacturing method of the porous film of this embodiment includes the heat setting process which heat-set preferably at 110 degreeC or more and 135 degrees C or less with respect to the film obtained through the heat | fever extending | stretching process. As a method of heat setting, a method of heat shrinking to such an extent that the length of the film after heat setting is reduced by 3 to 50% with respect to the length of the microporous film before heat setting (hereinafter referred to as “method And heat-setting so as not to change the dimension in the stretching direction.
The heat setting temperature is preferably 110 ° C. or more and 135 ° C. or less, more preferably 115 ° C. or more and 130 ° C. or less. Here, the heat setting temperature is the surface temperature of the porous film in the heat setting process.

  Hereinafter, the present embodiment will be described in detail by way of examples, but the present embodiment is not limited to only these examples.

<Average degree of polymerization of cellulose>
It measured by the reduction specific viscosity method by the copper ethylenediamine solution prescribed | regulated to the crystalline cellulose confirmation test (3) of "the 14th revision Japanese Pharmacopoeia" (Ashikawa Shoten publication).

Crystallinity of Cellulose
The diffraction image was measured (normal temperature) by a powder method using an X-ray diffractometer (multipurpose X-ray diffractometer manufactured by Rigaku Corporation), and the degree of crystallinity was calculated by the Segal method.

<Long diameter of cellulose particle>
The major axis of cellulose was measured by the following method.
First, 5 to 10% by mass of cellulose powder is dissolved in pure water with respect to the weight of water, and after sufficiently dispersing cellulose using a biomixer (BM-4) manufactured by Nippon Seiki, 0.1 to 0.5% by mass Diluted with pure water to a concentration of
After that, cast on mica and air-dried ones, and observe them with a high resolution scanning microscope (SEM) or an atomic force microscope (AFM), and image analysis of 100 to 150 particle images obtained by the observation. The average major axis was calculated by calculation using software.

<L / D of cellulose particles>
An aqueous solution having a concentration of 0.1 to 0.5% by mass was prepared, cast on mica, and air-dried in the same manner as the above-mentioned method for measuring the major axis. The ratio (L / D) of the major axis (L) to the minor axis (D) of the particle image obtained when observed with a high resolution scanning microscope (SEM) or an atomic force microscope (AFM) is determined, and 100 It was calculated as the average value of the number of particles of ~ 150.

<Colloidal cellulose content>
Each cellulose was made into solid content 40 mass%, and it knead | mixed for 30 minutes under room temperature normal pressure at 126 rpm in a planetary mixer (Shinagawa Kogyo Co., Ltd. product 5DM-03-R, a stirring blade is a hook type | mold).
Next, a pure water suspension having a solid content of 0.5% by mass was used, and a high shear homogenizer (manufactured by Nippon Seiki Co., Ltd., trade name "Excel Auto Homogenizer ED-7" treatment conditions: rotational speed 15,000 rpm Dispersed using × 5 minutes, and centrifuging (manufactured by Kubota Shoji Co., Ltd., trade name “6800 type centrifuge”, rotor type RA-400 type, processing conditions: supernatant for 10 minutes at a centrifugal acceleration of 39240 m / s 2 The supernatant was further centrifuged at 117,720 m / s ² for 45 minutes.) The solid content remaining in the supernatant after centrifugation was determined by absolute drying, and the colloidal cellulose content was taken as a mass percentage. Calculated.

<Particle size of cellulose>
A solid content of 40% by mass of cellulose was kneaded for 30 minutes at room temperature and normal pressure at 126 rpm in a planetary mixer (5DM-03-R manufactured by Shinagawa Kogyosho Co., Ltd .; hook blade is a stirring blade).
Next, a pure water suspension having a solid content of 0.5% by mass was used, and a high shear homogenizer (manufactured by Nippon Seiki Co., Ltd., trade name "Excel Auto Homogenizer ED-7" treatment conditions: rotational speed 15,000 rpm The mixture was dispersed using × 5 minutes, and centrifuged (manufactured by Kubota Shoji Co., Ltd., trade name “6800 type centrifuge” rotor type RA-400 type, processing conditions: centrifuged for 10 minutes at a centrifugal force of 39,200 m ² / s The supernatant was collected, and the supernatant was further centrifuged at 116000 m ² / s for 45 minutes.) And the supernatant after centrifugation was collected. A volume frequency particle size obtained by a laser diffraction / scattering particle size distribution analyzer (trade name “LA-910” manufactured by Horiba, Ltd., trade name “LA-910”, ultrasonic treatment 1 minute, refractive index 1.20) using the above-mentioned supernatant liquid The integrated 50% particle size (volume average particle size) in the distribution was measured.

<MFR of raw material polyethylene resin and raw material polypropylene resin>
The MFR of the raw material polyethylene resin was measured in accordance with JIS K 7210: 1999 (A method code D temperature = 190 ° C, load = 2.16 kg).
The MFR of the raw material polypropylene resin was measured in accordance with JIS K 7210-1: 1999 (A method code M temperature = 230 ° C., load = 2.16 kg).

<Density measurement of raw material polyethylene resin and raw material polypropylene resin>
The densities of the raw material polyethylene resin and polypropylene resin were measured in accordance with JIS K7112: 1999.

[Polyethylene resin]
<PE-1>
A polyethylene powder having a density of 963 kg / m ^{3 and} a MFR of 0.21 g / 10 minutes manufactured by Asahi Kasei Co., Ltd. was used.
<PE-2>
A polyethylene powder of MFR 0.25 g / 10 min, density 956 kg / m ³ manufactured by Asahi Kasei Co., Ltd. was used.
<PE-3>
A polyethylene powder having a density of 963 kg / m ^{3 and} a MFR of 1.35 g / 10 min manufactured by Asahi Kasei Co., Ltd. was used.
<PE-4>
A polyethylene powder having a density of 952 kg / m ^{3 and} a MFR of 0.8 g / 10 minutes manufactured by Asahi Kasei Co., Ltd. was used.
<PE-5>
A polyethylene powder of MFR 0.05 g / 10 min, density 952 kg / m ³ manufactured by Asahi Kasei Co., Ltd. was used.
<PE-6>
A polyethylene powder having a density of 951 kg / m ^{3 and} a MFR of 5.0 g / 10 min manufactured by Asahi Kasei Co., Ltd. was used.
<PE-7>
A polyethylene powder of MFR 2.0 g / 10 min, density 925 kg / m ³ manufactured by Asahi Kasei Co., Ltd. was used.
<PE-8>
A polyethylene pellet of MFR 1.35 g / 10 min, density 963 kg / m ³ manufactured by Asahi Kasei Co., Ltd. was used.

[Polypropylene resin]
<PP-1>
Nippon Polypropylene Corporation MFR 0.4 g / 10 min, with a density of 910 kg / m ³ pellets of Novatek PP, while cooling with dry ice, rotating at 10,000 rpm or more with Absolute Chemical ABS-W manufactured by Osaka Chemical Co., Ltd. The mixture was mixed for 30 minutes or more at a speed and used as a powder.
<PP-2>
A pellet of Novatek PP having a density of 900 kg / m ³ and MFR of 11 g / 10 min, manufactured by Nippon Polypropylene Corp., was powdered in the same manner as PP-1 and used.
<PP-3>
A pellet of Novatek PP having a density of 900 kg / m ³ and MFR of 30 g / 10 min, manufactured by Nippon Polypropylene Corp., was pulverized in the same manner as PP-1 was used.
<PP-4>
A pellet of Novatek PP having a density of 900 kg / m ³ and MFR of 60 g / 10 min, manufactured by Nippon Polypropylene Corporation, was pulverized in the same manner as PP-1 was used.

[cellulose]
After cutting hardwood-derived KP pulp (average degree of polymerization: 1000), it is hydrolyzed in 4.0 mol / L hydrochloric acid at 105 ° C. for 180 minutes, then washed with water and filtered to obtain a wet cake-like product having a solid content of 40% by mass. A cellulose was prepared (average polymerization degree 180, crystallinity degree 78%, average major axis 358 nm, particle L / D = 1.6, colloidal cellulose content 68 mass%, particle diameter 0.13 μm).
Water is added such that the solid content concentration of the above cellulose is 10% by mass, and the cellulose is uniformly dispersed in water by stirring for 30 minutes or more at 6,000 rpm or more using a biomixer (BM-4) manufactured by Nippon Seiki Co., Ltd. The slurry was prepared.
After the slurry preparation, oil, grease, wax and the like may be added.

[Determination of crystallization rate, crystallization peak and endothermic enthalpy by DSC]
The DSC measurement apparatus used DSC8000 made by PERKIN ELMER.
The measurement was performed at a heating rate of 10 ° C./min from 50 ° C. to a temperature at which the resin was completely melted. The above implementation is 1st. Call it Heating. The maximum temperature can be appropriately selected according to the melting point of the polyolefin resin to be used, and 180 ° C. for polyethylene resin and 200 ° C. for polypropylene resin.
Next, the temperature was lowered from the temperature at which the resin melted to 50 ° C. at a rate of 10 ° C./min. The above temperature drop is 1st. The peak of the extrapolated crystallization start temperature and the crystallization temperature of the resin was read from a curve called Coolin, which was measured in this process.
Finally, the measurement was carried out at a temperature rising rate of 10 ° C./min from 50 ° C. to the melting temperature of the resin again. 2nd. Call it Heating. The endothermic enthalpy was read from the curve measured in this process. The endothermic enthalpy [J / g] in the resin composition was calculated by converting the value read from DSC into 1 g of resin.

<Measurement method and definition of 1⁄2 isothermal crystallization time>
The temperature was maintained at a constant temperature 4 ° C. higher than the extrapolation crystallization start temperature determined above for 40 minutes. The time at which the exothermic curve measured at this time had a peak was defined as 1⁄2 isothermal crystallization time.

<Method of producing porous film>
[Film formation]
Inflation film production apparatus (D-50, manufactured by Sumitomo Heavy Industries, Ltd.) (screw diameter 50 mm, screw: L (extrusion screw length) / D (extrusion screw diameter) = 28, die: lip diameter, 100 mm, lip gap , 5.0 mm), cylinder temperature 180 ° C, die temperature 180 ° C, extrusion amount 5.0 kg / hour, blow ratio 1.0, blow out cooling air to 10 mm above the die surface (frost height 10 mm) Then, the film was cooled and the film formation was stabilized to obtain a 30 μm thick polyethylene resin composition film.

[Heat treatment]
The polyethylene resin composition film formed into a film from the above-mentioned inflation molding apparatus was heat-treated (annealed) in a gear oven at 120 ° C. for 3 hours.

[Cold stretch]
The above polyethylene resin composition film is cut into a width of 100 mm and a length of 200 mm (the MD direction is a long side), and then a tensile tester (RTC-1310A, manufactured by Orientec Co., Ltd.) is used to make the film 100 mm between chucks. The film was attached, and cold stretching was performed 1.5 times at a tensile speed of 200 mm / min in the MD direction of the film at 23 ° C.

[Heat stretch]
Immediately after performing cold stretching, set the oven heated to 120 ° C, heat for 30 seconds, perform 2.0 times heat stretching in the MD direction at a tensile speed of 300 mm / min and heat fix for 60 seconds to obtain a porous film I got

[Measurement of air permeability]
The air resistance of the microporous film was measured using a Gurley air permeability meter (manufactured by Toyo Seiki Seisakusho, Ltd.) in accordance with JIS P-8117. The measured value was converted to a film thickness of 20 μm. Furthermore, in the production of the microporous film described above, the porosity of the microporous film obtained by changing the heat drawing ratio in the range of 1.7 times to 2.5 times is measured, and the air permeability (20 μm The value of porosity) and the value of porosity are expressed as a functional equation, and the air permeability (thickness: 20 μm, porosity 50% equivalent) at which the porosity is 50% was calculated from the approximate curve of the functional equation.
The higher the air permeability of the microporous film, the smaller the numerical value of the air permeability.

[Measurement of piercing strength]
The measurement was performed using a digital force gauge (ZP20N, manufactured by Imada Co., Ltd.).
First, the microporous film obtained by the above method is fixed to a sample holder (TKS20N) with an opening diameter of 10 mm, and a needle having a radius of curvature of 0.5 mm at the center of the fixed microporous film is used. The piercing strength (g) as the maximum piercing load was measured by performing a piercing test under a piercing speed = 12 mm / min, 23 ° C., 50% humidity atmosphere. The obtained puncture strength was converted to a thickness of 20 μm.

[Examples 1 to 15]
[Preparation of Resin Composition]
A slurry (or a slurry mixture) containing 10% by mass of the above cellulose was sufficiently mixed with the composition as shown in Tables 1A and 1B to obtain a mixture. The above mixture was oven dried at 80 ° C. for 1 hour. The dried mixture was kneaded for 20 minutes with a Labo Plastomill Model No. 4C150 manufactured by Toyo Seiki Co., Ltd., at 145 ° C. and 50 rpm for polyethylene, and for 20 minutes at 180 ° C. and 50 rpm for polypropylene.
Under the above conditions, a resin composition was prepared with a composition as shown in the table to obtain a microporous film. The results are as shown in the table.
In Examples 4, 7 and 15, Emano CH-25 manufactured by Kao Corporation was further added to the resin composition. In Example 5, Emano CH-40 manufactured by Kao Corporation was further added to the resin composition. In Example 8, polyglycerin polyricinolate PR-100 manufactured by Riken Vitamin Co., Ltd. was further added to the resin composition. In Example 14, Emano CH-60 manufactured by Kao Corporation was used.

[Comparative Examples 1 to 8]
In Comparative Examples 1 to 5 and 7 to 8, samples were prepared in the same manner as in Example 1 with the compositions described in Table 2. In Comparative Example 6, PE-8 (pellet) was used.

  The resin composition of the present invention has industrial applicability in porous films, battery separators, transparent films, diffusion films, automobile parts and the like.

Claims (6)

A resin composition comprising a polyolefin resin and cellulose,
The cellulose is cellulose having an average major axis of 5 μm or less,
The content of the cellulose is 0.05 to 15.0 parts by mass with respect to a total of 100 parts by mass of the polyolefin resin and the cellulose,
The resin composition whose 1/2 isothermal crystallization time in temperature higher 4 degreeC than the extrapolation crystallization start temperature of a differential scanning calorimeter (DSC) is 15 minutes or less.   The resin composition according to claim 1, wherein the cellulose is crystalline cellulose. The ethylene alone, wherein the polyolefin resin has an MFR (measured at 190 ° C. under a load of 2.16 kg according to JIS K 7210) of 0.1 to 2.0 g / 10 min and a density of 950 to 970 kg / m ³ A polymer and / or an ethylene copolymer,
The temperature of the crystallization peak during the temperature lowering process of DSC is 112 ° C. or higher,
The resin composition according to claim 1 or 2, wherein an endothermic enthalpy (ΔH ₂ ) in a temperature rising process is 190 J / g or more and 220 J / g or less in terms of resin. The polyolefin resin is a polypropylene homopolymer and / or a polypropylene copolymer having an MFR (measured at 230 ° C. under a load of 2.16 kg according to JIS K 7210-1) of 0.1 to 60 g / 10 min. Yes,
The temperature of the crystallization peak in the temperature lowering process of DSC is 120 ° C. or higher,
The resin composition according to claim 1 or 2, wherein an endothermic enthalpy (ΔH ₂ ) in a temperature rising process is 115 J / g or more and 140 J / g or less in terms of resin.   The resin composition as described in any one of Claims 1-4 containing the oil and / or wax which have a polyoxyethylene chain in a molecule | numerator.   The porous film produced from the resin composition as described in any one of Claims 1-5.