WO2025239197A1 - Propylene-based resin composition and molded body - Google Patents

Abstract

Provided are: a molded body capable of reducing the generation of odor while maintaining excellent tensile elastic modulus; and a propylene-based resin composition capable of producing said molded body.　This propylene-based resin composition comprises a propylene-based polymer and propanol, wherein the content of the propanol is 0.01-30 ppm by mass when the total mass of the propylene-based resin composition is 100 parts by mass. Moreover, this molded body comprises said resin composition.

Description

Propylene-based resin composition and molded article

The present invention relates to a propylene-based resin composition and a molded article.

A propylene-based resin composition containing a propylene-based polymer has good mechanical properties and can be used in various applications, such as materials for home appliances, office automation equipment, medical equipment, and automobile parts, and is preferably used as a material for forming interior components (interior materials) of automobiles.
Patent Document 1 describes a propylene-based resin composition that has a good balance of physical properties such as rigidity and impact resistance and has improved weather resistance, and is intended for use as an interior material for automobiles.

Japanese Patent Application Laid-Open No. 2001-019825

Resin molded products can emit a distinctive odor inherent to the resin material, particularly in resin molded products that surround (or are familiar with) our living environment. Furthermore, in recent years, awareness of chemical safety has increased, leading to the development of countermeasures against sick house syndrome (SBS) and sick car syndrome, which is caused by odorous substances specific to new cars. Given this growing awareness, reducing odors from resin molded products while maintaining their excellent mechanical properties, such as tensile modulus, which is important for designing tough components and indicates resistance to small deformations in the tensile direction, is becoming increasingly important for ensuring a comfortable in-car environment, even if the odor is due to chemicals that are not directly harmful to the human body. Similarly, with the recent spread of electric vehicles, which require high flexural modulus, impact resistance, and precise control of electrical circuitry, high insulation properties are also being required for each component to prevent voltage and frequency disturbances caused by current flow. On the other hand, packaging films such as those for food packaging (pouches) are required to reduce odor generation while maintaining required properties such as gripping ability, ease of opening, stability of blocking strength, and tensile modulus of elasticity.
However, with regard to propylene-based resin compositions that can be used in various applications, there has been insufficient research into further improving odor while maintaining or improving these main properties, and Patent Document 1 does not make any research into this.

The objective of the present invention is to provide a molded article that reduces odor generation while maintaining an excellent tensile modulus, and a propylene-based resin composition from which such a molded article can be produced.

The present inventors have conducted extensive research to solve the above problems and have found that by adding a specific amount of propanol to a propylene-based resin composition, it is possible to reduce odor generation while maintaining an excellent tensile modulus, thereby completing the present invention.
That is, the object of the present invention has been achieved by the following means.
[1] A propylene-based resin composition containing a propylene-based polymer and propanol,
The propylene-based resin composition has a propanol content of 0.01 to 30 ppm by mass when the total mass of the propylene-based resin composition is 100 parts by mass.
[2] The propylene-based resin composition according to claim 1, wherein the propanol includes 2-propanol.
[3] The propylene-based resin composition according to [1] or [2], wherein the content of the propylene-based polymer is 50 parts by mass or more, relative to 100 parts by mass of the total mass of the propylene-based resin composition.
[4] The propylene-based resin composition according to any one of [1] to [3], further comprising an ethylene-α-olefin copolymer.
[5] The propylene-based resin composition according to [4], wherein the content of the ethylene-α-olefin copolymer is 1 to 40 parts by mass, relative to 100 parts by mass of the propylene-based resin composition.
[6] The propylene-based resin composition according to any one of [1] to [5], further comprising an inorganic filler.
[7] The propylene-based resin composition according to [6], wherein the content of the inorganic filler is 1 to 40 parts by mass when the total mass of the propylene-based resin composition is 100 parts by mass.
[8] The propylene-based resin composition according to any one of [1] to [7], having an MFR (230°C, 2.16 kgf) of less than 20 g/10 min.
[9] The propylene-based resin composition according to any one of [1] to [8], wherein the propylene-based polymer contains a heterophasic propylene polymer material.
[10] The propylene-based resin composition according to any one of [1] to [8], wherein the propylene-based polymer comprises a propylene-based random copolymer.
[11] The propylene-based resin composition according to [10], wherein the propylene-based random copolymer contains a propylene-butene copolymer.
[12] A molded article comprising the propylene-based resin composition according to any one of [1] to [11] above.
[13] The molded article according to [12], which is a film.

The present invention provides a molded article that reduces odor generation while maintaining an excellent tensile modulus, and a propylene-based resin composition from which such a molded article can be produced.

The present invention will be described in detail below. The present invention is not limited to the specific embodiments shown below.

[[Terminology Explanation]]
Before describing the present invention, commonly used terms will first be explained.
In the present invention and this specification, the term "monomer unit" refers to a structural unit (residue) derived from a monomer contained in a polymer obtained by polymerizing a monomer.
In the present invention and this specification, the term "α-olefin" refers to an olefin containing a carbon atom chain consisting of three or more carbon atoms and having a carbon-carbon double bond at the terminal side (α-position (also referred to as 1-position)).

In this invention and this specification, "melt flow rate (MFR)" means "melt mass flow rate," and unless otherwise specified, is the melt flow rate measured in accordance with JIS K 7210-1:2014 and JIS K 7210-2:2014 under conditions of a temperature of 230°C and a load of 2.16 kgf.

In this invention and this specification, unless otherwise specified, "%" means "% by mass" and "parts" means "parts by mass."

In the present invention and this specification, the bonding mode (arrangement of the structural units) of two or more structural units in a copolymer that becomes a resin or elastomer is not particularly limited, and unless otherwise specified, may be any bonding mode, such as random bonding (random copolymer), block bonding (block copolymer), alternating bonding (alternating copolymer), or graft bonding (graft copolymer).

In this invention and this specification, when describing content, physical properties, etc. using numerical ranges, if the upper and lower limits of the numerical range are described separately, any of the upper and lower limits can be combined as appropriate to form a specific numerical range. On the other hand, when describing multiple numerical ranges expressed using "~", the upper and lower limits that form the numerical range are not limited to the combination of the specific upper and lower limits written before and after "~" as a specific numerical range, but can be any numerical range formed by appropriately combining the upper and lower limits of each numerical range. Note that in this invention and this specification, a numerical range expressed using "~" means a range that includes the numerical values written before and after "~" as the upper and lower limits.

[[Propylene-based resin composition]]
The propylene-based resin composition of the present invention contains a propylene-based polymer (hereinafter, sometimes referred to as "propylene-based polymer (A)") and propanol (hereinafter, sometimes referred to as "propanol (B)"). The content of propanol (B) is 0.01 to 30 ppm by mass when the total mass of the propylene-based resin composition is 100 parts by mass.
The propylene-based resin composition of the present invention containing propanol (B) in the above-mentioned content can, when molded, maintain an excellent tensile modulus while suppressing odor generation to a level that does not cause discomfort, for example, thereby realizing a molded article that combines an excellent tensile modulus with suppressed odor generation. Furthermore, in a preferred embodiment, the propylene-based resin composition of the present invention can, when molded into a sheet-like article, maintain or improve an excellent tensile modulus, as well as flexural modulus, impact resistance, and insulating properties, while suppressing odor generation to a level that does not cause discomfort, for example, thereby realizing a molded article that combines excellent tensile modulus, flexural modulus, impact resistance, and/or insulating properties with suppressed odor generation. Furthermore, in another preferred embodiment, the propylene-based resin composition of the present invention can, when molded into a sheet-like article, maintain or improve an excellent tensile modulus, as well as stability of gripping properties, openability, and blocking strength, while suppressing odor generation to a level that does not cause discomfort, for example, thereby realizing a molded article that combines excellent tensile modulus, gripping properties, openability, and/or blocking strength stability with suppressed odor generation.

First, the components contained in the propylene-based resin composition of the present invention will be described.
The propylene-based resin composition of the present invention may contain one or more of each of the components.

[Propylene-based polymer]
The propylene polymer (A) refers to a polymer containing propylene-derived units (also referred to as "propylene units") in an amount of more than 50% by mass relative to all constituent units (100% by mass). The propylene units in the propylene polymer (A) are usually 100% by mass or less.

Propylene-based polymers include propylene homopolymers and copolymers obtained by polymerizing propylene with one or more other monomers copolymerizable with propylene in any combination in any ratio. Such copolymers may be random copolymers or block copolymers.

Other monomers that can be copolymerized with propylene include olefins other than propylene (e.g., ethylene and olefins having 4 or more carbon atoms). There is no particular upper limit on the number of carbon atoms in the olefin, but it can be, for example, 12 or less.

Olefins with 4 or more carbon atoms may be linear or branched olefins. Olefins with 4 or more carbon atoms may also be olefins with a cyclic structure, such as vinylcyclopropane and vinylcyclobutane.

Olefins other than propylene that can be copolymerized with propylene include olefins other than propylene (e.g., ethylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, and 1-decene). Olefins other than propylene that can be copolymerized with propylene are preferably ethylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, and 1-decene, and more preferably ethylene, 1-butene, 1-hexene, and 1-octene.

<Propylene homopolymer>
From the viewpoint of improving the fluidity of the propylene-based resin composition when melted and the toughness of a molded article containing the propylene-based resin composition, the propylene homopolymer preferably has an intrinsic viscosity [η] of 0.1 to 5 dL/g, more preferably 0.5 to 4 dL/g, and even more preferably 0.6 to 3 dL/g.

Furthermore, from the viewpoint of improving the fluidity of the propylene-based resin composition when melted and the toughness of molded articles containing the propylene-based resin composition, the propylene homopolymer preferably has a molecular weight distribution Mw/Mn of 2 or more and less than 10, more preferably 3 to 8, and even more preferably 3 to 6. Here, Mw represents the weight-average molecular weight, and Mn represents the number-average molecular weight. The molecular weight distribution can be measured by gel permeation chromatography (GPC).

<Propylene-based random copolymer>
Examples of the propylene-based random copolymer include a random copolymer containing propylene units and units derived from ethylene (also referred to as "ethylene units") (hereinafter also referred to as "random polymer (1)"), a random copolymer containing propylene units and units derived from an olefin having 4 or more carbon atoms (also referred to as "olefin units") (hereinafter also referred to as "random polymer (2)"), and a random copolymer containing propylene units, ethylene units, and olefin units (hereinafter also referred to as "random polymer (3)").

Olefins with 4 or more carbon atoms that can constitute the propylene-based random copolymer are preferably olefins with 4 to 10 carbon atoms. Examples of olefins with 4 to 10 carbon atoms include 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, and 1-decene, with 1-butene, 1-hexene, and 1-octene being preferred.

Random copolymers (2) include propylene-1-butene random copolymers, propylene-1-hexene random copolymers, propylene-1-octene random copolymers, and propylene-1-decene random copolymers, with propylene-butene random copolymers being preferred.

Examples of the random copolymer (3) include propylene-ethylene-1-butene random copolymer, propylene-ethylene-1-hexene random copolymer, propylene-ethylene-1-octene random copolymer, and propylene-ethylene-1-decene random copolymer.
In the present invention, the propylene-1-olefin copolymer may be referred to as a propylene-α-olefin copolymer or a propylene-olefin copolymer.

The content of ethylene units in the random copolymer (1) is preferably 0.1 to 40% by mass.

The content of olefin units in the random copolymer (2) is preferably 0.1 to 40% by mass, more preferably 0.1 to 30% by mass, and even more preferably 2 to 15% by mass.

The total content of ethylene units and olefin units in the random copolymer (3) is preferably 0.1 to 40% by mass, more preferably 0.1 to 30% by mass, and even more preferably 2 to 15% by mass.

The propylene unit content in each of these random copolymers (1) to (3) is preferably 60 to 99.9% by mass.

Propylene-based polymer (A) can be produced, for example, by the following polymerization method using a polymerization catalyst.

Polymerization catalysts include Ziegler-type catalyst systems; Ziegler-Natta-type catalyst systems; catalyst systems containing a Group 4 transition metal compound having a cyclopentadienyl ring and an alkylaluminoxane; catalyst systems containing a Group 4 transition metal compound having a cyclopentadienyl ring, a compound that reacts with the metal compound to form an ionic complex, and an organoaluminum compound; and catalyst systems in which catalyst components (e.g., Group 4 transition metal compound having a cyclopentadienyl ring, a compound that forms an ionic complex, an organoaluminum compound, etc.) are supported on inorganic particles (e.g., silica, clay minerals, etc.) and modified. Prepolymerization catalysts prepared by prepolymerizing monomers such as ethylene or α-olefins in the presence of such catalyst systems may also be used. Ziegler-Natta-type catalyst systems include catalyst systems that use a combination of a titanium-containing solid transition metal component and an organometallic component.

Examples of such catalyst systems include those described in JP-A-61-218606, JP-A-5-194685, JP-A-7-216017, JP-A-9-316147, and JP-A-10-212319, and, for heterophasic propylene polymerization materials, JP-A-2004-182981. The contents of the above-mentioned patent documents may be referenced as appropriate in this specification, and the contents thereof are incorporated herein in their entirety as part of the present specification.

Polymerization methods include bulk polymerization, solution polymerization, and gas-phase polymerization. Here, bulk polymerization refers to a method in which polymerization is carried out using a liquid olefin as the medium at the polymerization temperature. Solution polymerization refers to a method in which polymerization is carried out in an inert hydrocarbon solvent such as propane, butane, isobutane, pentane, hexane, heptane, or octane. Gas-phase polymerization refers to a method in which gaseous monomers are used as the medium and the gaseous monomers are polymerized in that medium.

When carrying out the polymerization method, the polymerization method may be a batch method, a continuous method, or a combination of these. The polymerization method may also be a multi-stage method using multiple polymerization reactors connected in series.

The various conditions used in the polymerization method (polymerization temperature, polymerization pressure, monomer concentration, catalyst input amount, polymerization time, etc.) can be determined appropriately depending on the desired propylene-based polymer.

In the production of a propylene-based polymer, the resulting propylene-based polymer may be maintained at a temperature at which impurities such as residual solvents and the oligomers can volatilize, but below the temperature at which the propylene-based polymer melts, to remove residual solvents contained in the resulting propylene-based polymer and ultra-low molecular weight oligomers produced as by-products during production. Examples of methods for removing impurities such as residual solvents and oligomers include those described in Japanese Patent Laid-Open No. 55-75410 and Japanese Patent No. 2,565,753. The contents of these patent documents may be referenced herein as appropriate, and the contents thereof are incorporated herein in their entirety.

The propylene-based resin composition of the present invention may contain two or more types of propylene-based polymers as the propylene-based polymer (A).

When two or more propylene polymers are contained, combinations of two or more propylene polymers include combinations of two or more propylene homopolymers with different weight average molecular weights, combinations of two or more propylene random copolymers with different olefin units, and heterophasic propylene polymer materials.

Examples of combinations of two or more propylene-based random copolymers with different olefin units include a mixture of two or more propylene-based random copolymers (2), a mixture containing propylene-based random copolymer (1) and propylene-based random copolymer (2), and a mixture containing propylene-based random copolymer (1) and propylene-based random copolymer (3). Each of the above mixtures includes a mixture obtained by simply mixing two or more copolymers (synthesized separately) and a propylene-based multistage polymer obtained by a multistage polymerization method using different olefins in at least two polymerization stages. In the propylene-based multistage polymer, it is preferable to synthesize at least one of the copolymers in a two-stage polymerization stage, and synthesize the other copolymer in the second or subsequent polymerization stage. The method for producing the propylene-based multistage polymer is not particularly limited, and for example, the method for producing a heterophasic propylene polymer material described below can be used.
In the case of a combination of two or more propylene-based random copolymers, it means a material in which one copolymer and the other copolymer are compatible with each other, for example, a material in which they form a homogeneous phase as a whole.

In the present invention, the term "heterophasic propylene polymer material" refers to a material containing two or more types of propylene polymers, in which the two or more types of propylene polymers are not compatible with each other and form separate phases.

Heterophasic propylene polymer materials include materials containing a combination of polymer (I) and polymer (II) below.

Here, polymer (I) is a polymer having more than 80% by mass and 100% by mass or less of propylene units relative to the amount of all constituent units. Polymer (I) may be a propylene homopolymer or a copolymer of propylene and other monomers. The total content of monomer units other than propylene units in polymer (I), when the mass of polymer (I) is taken as 100% by mass, is usually 0% by mass or more and less than 20% by mass, and may be 0% by mass or 0.01% by mass or more.

Examples of monomer units other than propylene units that may be contained in polymer (I) include ethylene units and olefin units having 4 or more carbon atoms. There is no particular upper limit on the number of carbon atoms in the olefin that constitutes the olefin unit, but it can be, for example, 12 or less.

The olefin having 4 or more carbon atoms that can constitute polymer (I) may be linear, branched, or cyclic. The olefin is preferably an olefin having 4 to 10 carbon atoms, more preferably 1-butene, 1-hexene, and 1-octene, and even more preferably 1-butene.

Examples of polymer (I) include propylene homopolymer, propylene-ethylene copolymer, propylene-1-butene copolymer, propylene-1-hexene copolymer, propylene-1-octene copolymer, propylene-ethylene-1-butene copolymer, propylene-ethylene-1-hexene copolymer, and propylene-ethylene-1-octene copolymer.

Among these, for example, propylene homopolymer, propylene-ethylene copolymer, propylene-1-butene copolymer, and propylene-ethylene-1-butene copolymer are preferred as polymer (I), and propylene homopolymer is more preferred from the viewpoint of improving the rigidity of molded articles containing the propylene-based resin composition.

Furthermore, polymer (II) is a copolymer of propylene units and at least one monomer unit selected from the group consisting of ethylene units and olefin units having 4 or more carbon atoms. Polymer (II) is preferably a polymer having propylene units in an amount of more than 0% by mass and not more than 90% by mass, and more preferably more than 0% by mass and not more than 80% by mass, based on the mass of all constituent units. Polymer (II) may be a random copolymer or a block copolymer.

The total content of ethylene units and olefin units having 4 or more carbon atoms in polymer (II) is preferably 20 to 80% by mass, and more preferably 20 to 60% by mass, when the mass of polymer (II) is taken as 100% by mass.

The olefin having 4 or more carbon atoms that can constitute polymer (II) is preferably an olefin having 4 to 10 carbon atoms, and is the same as the olefin that can constitute polymer (I) already described.

Examples of polymer (II) include propylene-ethylene copolymer, propylene-ethylene-1-butene copolymer, propylene-ethylene-1-hexene copolymer, propylene-ethylene-1-octene copolymer, propylene-ethylene-1-decene copolymer, propylene-1-butene copolymer, propylene-1-hexene copolymer, propylene-1-octene copolymer, and propylene-1-decene copolymer. Polymer (II) is preferably a propylene-ethylene copolymer, propylene-1-butene copolymer, or propylene-ethylene-1-butene copolymer, and more preferably a propylene-ethylene copolymer.

The content of polymer (II) in the heterophasic propylene polymerization material is preferably 1 to 50% by mass, more preferably 1 to 45% by mass, even more preferably 5 to 40% by mass, and particularly preferably 7 to 35% by mass, when the total mass of polymer (I) and polymer (II) is taken as 100% by mass.

Polymer (I) and polymer (II) may each consist of only one type of polymer, or may contain two or more types of polymers.

Examples of heterophasic propylene polymer materials include those in which polymer (I) is a propylene homopolymer, combinations of a propylene homopolymer and a (propylene-ethylene) copolymer, combinations of a propylene homopolymer and a (propylene-ethylene-1-butene) copolymer, combinations of a propylene homopolymer and a (propylene-ethylene-1-hexene) copolymer, combinations of a propylene homopolymer and a (propylene-ethylene-1-octene) copolymer, combinations of a propylene homopolymer and a (propylene-1-butene) copolymer, combinations of a propylene homopolymer and a (propylene-1-hexene) copolymer, combinations of a propylene homopolymer and a (propylene-1-octene) copolymer, and combinations of a propylene homopolymer and a (propylene-1-decene) copolymer.

Furthermore, the heterophasic propylene polymer material may be a combination in which polymer (I) is a polymer containing propylene units and monomer units other than propylene units. Listing the type of polymer (I) first and the type of polymer (II) second, specific examples of such heterophasic propylene polymer materials include, for example, a combination of a (propylene-ethylene) copolymer and a (propylene-ethylene) copolymer, a combination of a (propylene-ethylene) copolymer and a (propylene-ethylene-1-butene) copolymer, a combination of a (propylene-ethylene) copolymer and a (propylene-ethylene-1-hexene) copolymer, a combination of a (propylene-ethylene) copolymer and a (propylene-ethylene-1-octene) copolymer, and a combination of a (propylene-ethylene) copolymer and a (propylene-ethylene-1-octene) copolymer. a combination of a (propylene-ethylene) copolymer and a (propylene-1-decene) copolymer, a combination of a (propylene-ethylene) copolymer and a (propylene-1-butene) copolymer, a combination of a (propylene-ethylene) copolymer and a (propylene-1-hexene) copolymer, a combination of a (propylene-ethylene) copolymer and a (propylene-1-octene) copolymer, a combination of a (propylene-ethylene) copolymer and a (propylene-1-decene) copolymer, a combination of a (propylene-1-butene) copolymer and a (propylene-ethylene) copolymer, a combination of a (propylene-1-butene) copolymer and a (propylene-ethylene-1-butene) copolymer a combination of a (propylene-1-butene) copolymer and a (propylene-ethylene-1-hexene) copolymer, a combination of a (propylene-1-butene) copolymer and a (propylene-ethylene-1-octene) copolymer, a combination of a (propylene-1-butene) copolymer and a (propylene-ethylene-1-decene) copolymer, a combination of a (propylene-1-butene) copolymer and a (propylene-1-butene) copolymer, a combination of a (propylene-1-butene) copolymer and a (propylene-1-hexene) copolymer, a combination of a (propylene-1-butene) copolymer and a (propylene-1-octene) copolymer Examples of such copolymers include a combination of a (propylene-1-butene) copolymer and a (propylene-1-decene) copolymer, a combination of a (propylene-1-hexene) copolymer and a (propylene-1-hexene) copolymer, a combination of a (propylene-1-hexene) copolymer and a (propylene-1-octene) copolymer, a combination of a (propylene-1-hexene) copolymer and a (propylene-1-decene) copolymer, a combination of a (propylene-1-octene) copolymer and a (propylene-1-octene) copolymer, and a combination of a (propylene-1-octene) copolymer and a (propylene-1-decene) copolymer.

Preferred heterophasic propylene polymer materials that can be contained in the propylene-based resin composition of the present invention include a combination of a propylene homopolymer and a (propylene-ethylene) copolymer, a combination of a propylene homopolymer and a (propylene-ethylene-1-butene) copolymer, a combination of a (propylene-ethylene) copolymer and a (propylene-ethylene) copolymer, a combination of a (propylene-ethylene) copolymer and a (propylene-ethylene-1-butene) copolymer, and a combination of a (propylene-1-butene) copolymer and a (propylene-1-butene) copolymer, with a combination of a propylene homopolymer and a (propylene-ethylene) copolymer being more preferable.

Heterophagic propylene polymer materials can be produced by multi-stage polymerization, which includes a first polymerization step for producing polymer (I) and a second polymerization step for producing polymer (II) in the presence of polymer (I) produced in the first step. The polymerization can be carried out using the catalyst systems listed above as examples of catalysts that can be used in the production of propylene-based polymers.

In one preferred embodiment, the propylene polymer (A) contains one or more propylene random copolymers. In this embodiment, it is more preferable to contain two or more propylene random copolymers. For example, it is even more preferable to contain one or more propylene random copolymers selected from the group consisting of a combination of two or more propylene random copolymers differing in olefin units, etc., and a heterophasic propylene polymer material. In this embodiment, the propylene random copolymer may be any of the random polymers (1) to (3) described above, but preferably contains random polymer (2) or random copolymer (3), more preferably contains random polymer (2), and even more preferably contains a propylene-butene random copolymer. In this embodiment, the content of random copolymer (2) and/or random copolymer (3) is preferably 50% by mass or more, more preferably 60% to 95% by mass, and even more preferably 70% to 90% by mass, when the total mass of all polymers is 100% by mass.
In another preferred embodiment, the propylene polymer (A) contains at least one selected from the group consisting of propylene homopolymers and heterophasic propylene polymer materials.

The propylene polymer (A) has an isotactic pentad fraction (also referred to as the [mmmm] fraction) measured by ^13C -NMR of usually 0.96 or more, preferably 0.97 or more, and more preferably 0.98 or more. The closer the isotactic pentad fraction of the propylene polymer is to 1, the higher the stereoregularity of the molecular structure of the propylene polymer and the higher the crystallinity of the propylene polymer. When the propylene polymer is a copolymer, the isotactic pentad fraction can be measured for the chain of propylene units in the copolymer.

From the viewpoint of improving the processability of the propylene-based resin composition during molding, the propylene-based polymer (A) preferably has a melt flow rate (MFR) measured at a temperature of 230°C under a load of 2.16 kgf of 0.1 g/10 min or more, more preferably 0.5 g/10 min or more, and preferably 500 g/10 min or less, more preferably 400 g/10 min or less, and preferably 0.1 g/10 min to 500 g/10 min.

In addition, from the viewpoint of improving the fluidity and processability of the propylene-based resin composition, the intrinsic viscosity of the propylene-based polymer (A) of the present invention is usually less than 5 dL/g, 0.1 dL/g or more, preferably 0.5 dL/g or more, more preferably 0.7 dL/g or more but less than 4 dL/g, and even more preferably 0.8 dL/g or more but less than 3 dL/g.

In the present invention, the polystyrene-equivalent weight average molecular weight of the propylene polymer (A) is typically 100,000 to 1,000,000, and preferably 500,000 to 1,000,000, from the viewpoint of improving the appearance and elongation properties of the molded article.

From the viewpoint of improving moldability and mechanical properties, the molecular weight distribution (Mw/Mn) of the propylene polymer (A) may generally be 10 or less, and preferably 3 to 8.

Here, Mw represents the weight average molecular weight, and Mn represents the number average molecular weight. The weight average molecular weight, number average molecular weight, and molecular weight distribution can be measured by gel permeation chromatography (GPC) and calculated in terms of polystyrene.

When the propylene-based polymer is a copolymer mixture or polymerization material consisting of polymer (I) and polymer (II) formed by multi-stage polymerization, a portion of polymer (I) prepared in the first polymerization stage is extracted from the polymerization reactor and its intrinsic viscosity is determined, and the intrinsic viscosity of the propylene-based polymer finally obtained by multi-stage polymerization (hereinafter referred to as [η] Total) is determined. The intrinsic viscosity of the polymer formed in the second polymerization stage can be calculated using these intrinsic viscosity values and the content of each polymer.

Furthermore, when the mixture of copolymers consisting of polymer (I) and polymer (II) and the polymerization material are materials produced by a method in which polymer (I) is obtained in an earlier polymerization step and polymer (II) is obtained in a later polymerization step, the procedures for measuring and calculating the contents and intrinsic viscosities ([η] Total, [η] I, [η] II) of polymer (I) and polymer (II), respectively, are as follows.
Here, the polymer prepared in the first polymerization step is referred to as "polymer (I)" and the polymer prepared in the second polymerization step is referred to as "polymer (II)." In the mixture of two or more kinds of propylene-based random copolymers described above, both the polymer prepared in the first polymerization step and the polymer prepared in the second polymerization step correspond to any one of the propylene-based random copolymers (1) to (3).

The intrinsic viscosity [η]II of polymer (II) can be calculated by the following formula from the intrinsic viscosity ([η]I) of polymer (I) obtained in the previous polymerization step, the intrinsic viscosity ([η]Total) of the final polymer after the subsequent polymerization step (i.e., a polymer composed of polymer (I) and polymer (II)) measured by the above-mentioned method, and the content of polymer (II) contained in the final polymer.

[η]II=([η]Total-[η]I×XI)/XII

In the above formula,
[η] Total: intrinsic viscosity of the final polymer (unit: dL/g)
[η]I: Intrinsic viscosity of polymer (I) (unit: dL/g)
XI: mass ratio of polymer (I) to the final polymer. XII: mass ratio of polymer (II) to the final polymer. XI and XII can be determined from the mass balance during polymerization.

The intrinsic viscosity (hereinafter referred to as [η]I) of polymer (I) is preferably 0.1 to 5 dL/g, more preferably 0.5 to 4 dL/g, and even more preferably 0.6 to 3 dL/g.

The intrinsic viscosity of polymer (II) (hereinafter referred to as [η]II) is preferably 1 to 10 dL/g, more preferably 1.5 to 9 dL/g, and even more preferably 2 to 8 dL/g.

Furthermore, the ratio of [η]II to [η]I ([η]II/[η]I) is preferably 1 to 20, and more preferably 1 to 10.

The mass ratio XII of polymer (II) to the final polymer may be calculated from the following formula using the heat of crystalline fusion of polymer (I) and the final polymer, respectively.

XII=1-(ΔHf)T/(ΔHf)P

In the above formula,
(ΔHf)T: Heat of fusion of the final polymer (polymer (I) and polymer (II)) (unit: cal/g)
(ΔHf)P: heat of fusion of polymer (I) (unit: cal/g)

Furthermore, the molecular weight distribution (Mw/Mn) of polymer (I) measured by GPC is preferably 1 or more and less than 10, more preferably 2 or more and less than 7, and even more preferably 3 or more and less than 5.

The content of propylene polymer (A) in the propylene resin composition of the present invention is preferably 50 parts by mass or more, may be 60 parts by mass or more, may be 70 parts by mass or more, may be 80 parts by mass or more, may be 90 parts by mass or more, may be 99 parts by mass or less, may be 50 to 95 parts by mass, or may be 60 to 95 parts by mass, based on 100 parts by mass of the total mass of the propylene resin composition.

The propylene polymer (A) used in the present invention may contain one or more biomass-derived monomers. The same type of monomer constituting the polymer may be solely biomass-derived monomers, or may contain both biomass-derived monomers and fossil fuel-derived monomers. The biomass-derived monomer is a monomer obtained from any renewable natural raw material or its residue, such as plant- or animal ^- derived, including fungi, yeast, algae, and bacteria, and contains about ^10-12 carbon isotopes as carbon, and has a biomass carbon concentration (pMC) of about 100 (pMC) measured in accordance with ASTM D 6866. The biomass-derived monomer can be obtained by a conventionally known method. It is preferable that the propylene polymer (A) used in the present invention contains a biomass-derived monomer from the viewpoint of reducing the environmental load. If the polymer production conditions, such as the polymerization catalyst and polymerization temperature, are the same, even if the raw olefin contains biomass-derived olefins, the molecular structure, except for the inclusion of ^14C isotopes at a ratio of about ^10-12, is the same as that of a propylene-based polymer made from a fossil fuel-derived monomer. Therefore, the performance is said to be the same.

The propylene polymer (A) according to the present invention may also contain a chemically recycled monomer. The propylene constituting the polymer may consist solely of a chemically recycled monomer, or the polymer may contain a chemically recycled monomer together with a fossil fuel-derived monomer and/or a biomass-derived monomer. The chemically recycled monomer can be obtained by a conventionally known method. It is preferable for the propylene polymer (A) according to the present invention to contain a chemically recycled monomer from the viewpoint of reducing the environmental impact (mainly reducing waste). Even if the raw material monomer contains a chemically recycled monomer, the chemically recycled monomer is a monomer obtained by depolymerizing or pyrolyzing a polymer such as waste plastic back into a monomer unit such as propylene, or a monomer produced using such a monomer as a raw material. Therefore, if the polymer production conditions, such as the polymerization catalyst, polymerization process, and polymerization temperature, are equivalent, the molecular structure of the resulting propylene polymer will be equivalent to that of a fossil fuel-derived monomer. Therefore, the performance is also expected to be unchanged.

[Propanol]
The propylene-based resin composition of the present invention contains propanol.
In the present invention, examples of the propanol (B) include 1-propanol and 2-propanol, preferably 2-propanol, and more preferably 2-propanol. Note that the propanol may be a substituted propanol having various substituents, but is preferably an unsubstituted propanol having no substituents.

In the propylene-based resin composition of the present invention, the propanol content is 0.01 to 30 ppm by mass, assuming the total mass of the propylene-based resin composition to be 100 parts by mass. Possible odor-causing substances emitted by molded articles containing the propylene-based resin composition include the propylene-based polymer itself, such as oligomers; other components described below; and residues of the polymerization solvent for the propylene-based polymer; carboxylic acids, aldehydes, ketones, and alcohols generated by decomposition of the propylene-based polymer and other polymeric components due to thermal history; formaldehyde, acetaldehyde, acrolein, sulfur compounds, amine compounds, and other low-molecular-weight components generated by decomposition of additives. However, these substances cannot be uniquely identified by the composition of the propylene-based resin composition. However, by including propanol in the propylene-based resin composition in the above content, the generation of odor can be suppressed while maintaining excellent tensile modulus and other properties in the molded articles.

While the details of why the propylene-based resin composition of the present invention, containing propanol in the above-mentioned amount, can suppress odor generation while maintaining an excellent tensile modulus and, preferably, the above-mentioned key properties, are unclear, it is believed to be as follows. Specifically, propanol is present in the propylene-based resin composition of the present invention as a volatile component. It is believed that the molded article acts on human olfactory receptors, thereby preventing the perception of malodorous components emitted from the polypropylene resin composition and mitigating the odor, a so-called pairing effect. Therefore, by incorporating a small amount of propanol without excessively increasing the SVM (Signal Mean Variable Carbohydrate) content, which represents total VOC, a polypropylene resin composition with a good odor and molded articles made therefrom can be provided. Furthermore, propanol itself acts as an internal lubricant, promoting the orientation of elongated molecules in the resin flow direction during injection molding, which is believed to result in improvements in key properties such as the tensile modulus and Charpy impact strength. However, the inclusion of an excessive amount of propanol increases the thermal mobility of polypropylene molecules, thereby decreasing the tensile modulus and flexural modulus. Furthermore, propanol reduces the water content inside the molded body, which is a conductive material, which is presumably responsible for increasing the surface resistivity and improving insulation properties.

In the present invention, the content of propanol in the propylene-based resin composition is preferably 0.01 to 25 ppm by mass, more preferably 0.01 to 20 ppm by mass, and particularly preferably 0.15 to 10 ppm by mass, when the total mass of the propylene-based resin composition is taken as 100 parts by mass, in terms of achieving a good balance between the tensile modulus and the suppression of odor generation.
In the present invention, when the propylene-based resin composition is in the form of a molded article, the propanol content in the propylene-based resin composition (molded article) may be within the above-mentioned range, but may also be set to the following content: For example, the propanol content in the propylene-based resin composition (molded article) is preferably 0.02 to 30 ppm by mass, more preferably 0.05 to 20 ppm by mass, and particularly preferably 0.1 to 10 ppm by mass, when the total mass of the propylene-based resin composition (molded article) is taken as 100 parts by mass.
In the present invention, the propanol content in the propylene-based resin composition and in the molded article is a value measured by the method described in the examples below.

[Ethylene-α-olefin copolymer]
The propylene-based resin composition of the present invention may contain an ethylene-α-olefin copolymer (hereinafter, may be referred to as "ethylene-α-olefin copolymer (C)"). When the propylene-based resin composition of the present invention contains the ethylene-α-olefin copolymer (C), the impact resistance and other properties of the molded article can be improved.

The ethylene-α-olefin copolymer (C) may contain structural units other than ethylene units and α-olefin units. In the ethylene-α-olefin copolymer (C), when the total mass of all structural components of the ethylene-α-olefin copolymer is taken as 100 mass%, the sum of the ethylene unit content and the α-olefin unit content may be 100 mass%.

The α-olefin that forms the α-olefin unit is not particularly limited, but is preferably an α-olefin having 4 or more carbon atoms. Examples of α-olefins having 4 or more carbon atoms include α-olefins having 4 to 12 carbon atoms, specifically 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, and 1-decene. Of the α-olefins having 4 or more carbon atoms, α-olefins having 4 to 8 carbon atoms are preferred, with 1-butene, 1-hexene, and 1-octene being more preferred. The α-olefins may be linear or branched, or may be α-olefins having a cyclic structure such as vinylcyclopropane or vinylcyclobutane.

Examples of the ethylene-α-olefin copolymer (C) include ethylene-1-butene copolymer, ethylene-1-hexene copolymer, ethylene-1-octene copolymer, ethylene-1-decene copolymer, ethylene-(3-methyl-1-butene) copolymer, and copolymers of ethylene and an α-olefin having a cyclic structure.

In the ethylene-α-olefin copolymer (C), the content of α-olefin units is preferably 1 to 49% by mass, more preferably 5 to 49% by mass, and even more preferably 24 to 49% by mass, based on the total mass of all constituent components of the ethylene-α-olefin copolymer (100% by mass).

The MFR (measured at 190°C under a load of 2.16 kgf) of the ethylene-α-olefin copolymer (C) is not particularly limited, but is preferably, for example, 0.1 g/10 min or more and 100 g/10 min or less. It is more preferable that the MFR be 0.5 g/10 min or more and 70 g/10 min or less.

From the viewpoint of improving the impact resistance of the molded article, the density of the ethylene-α-olefin copolymer (C) is preferably 0.850 to 0.890 g/cm ³ , more preferably 0.850 to 0.880 g/cm ³ , and even more preferably 0.855 to 0.870 g/cm ³ .

Ethylene-α-olefin copolymer (C) can be produced by polymerizing ethylene and an α-olefin using a polymerization catalyst.

Polymerization catalysts used in production include, for example, homogeneous catalysts such as metallocene catalysts, and Ziegler-Natta catalysts.

Examples of homogeneous catalysts include catalysts consisting of a compound of a transition metal from Group 4 of the periodic table having a cyclopentadienyl ring and an alkylaluminoxane; catalysts consisting of a compound of a transition metal from Group 4 of the periodic table having a cyclopentadienyl ring, a compound that reacts with the transition metal compound to form an ionic complex, and an organoaluminum compound; and modified catalysts in which catalytic components (a compound of a transition metal from Group 4 of the periodic table having a cyclopentadienyl ring, a compound that forms an ionic complex, an organoaluminum compound, etc.) are supported on inorganic particles (silica, clay minerals, etc.).

An example of a Ziegler-Natta catalyst is a catalyst that combines a titanium-containing solid transition metal component with an organometallic component.

Commercially available products may be used as the ethylene-α-olefin copolymer component (C). Examples of commercially available ethylene-α-olefin copolymers (C) include ENGAGE (registered trademark) manufactured by Dow Chemical Japan, TAFMAR (registered trademark) manufactured by Mitsui Chemicals, Inc., NEOX (registered trademark) and ULTOX (registered trademark) manufactured by Prime Polymer Co., Ltd., and EXCELLEN FX (registered trademark), SUMIKACENE (registered trademark), and ESPRENE SPO (registered trademark) manufactured by Sumitomo Chemical Co., Ltd.

The content of the ethylene-α-olefin copolymer (C) in the propylene-based resin composition is preferably 1 to 40 parts by mass, more preferably 5 to 35 parts by mass, and even more preferably 5 to 30 parts by mass, relative to 100 parts by mass of the total amount (total mass) of the propylene-based resin composition.

The ethylene-α-olefin copolymer (C) used in the present invention may contain one or more biomass-derived monomers. The same type of monomer constituting the polymer may be solely biomass-derived monomers, or may contain both biomass-derived monomers and fossil fuel-derived monomers. From the viewpoint of reducing the environmental load, it is preferable that the ethylene-α-olefin copolymer (C) used in the present invention contains a biomass-derived monomer. As long as the polymer production conditions, such as the polymerization catalyst and polymerization temperature, are the same, even if the raw material olefin contains a biomass-derived olefin, the molecular structure, except for the inclusion of ^14C isotopes at a ratio of about ^10-12 , is equivalent to that of an ethylene-α-olefin copolymer composed of a fossil fuel-derived monomer. Therefore, the performance is also considered to be unchanged.

Furthermore, the ethylene-α-olefin copolymer (C) according to the present invention may contain a chemically recycled monomer. The monomers constituting the polymer may consist solely of chemically recycled monomers, or may contain chemically recycled monomers together with fossil fuel-derived monomers and/or biomass-derived monomers. Chemically recycled monomers are obtained by conventionally known methods. It is preferable for the ethylene-α-olefin copolymer (C) according to the present invention to contain a chemically recycled monomer from the perspective of reducing the environmental impact (mainly waste reduction). Even if the raw material monomer contains a chemically recycled monomer, the chemically recycled monomer is a monomer obtained by depolymerizing or pyrolyzing a polymer such as waste plastics to return it to monomer units such as ethylene, propylene, or butene, or a monomer produced using such a monomer as a raw material. Therefore, if the polymer production conditions, such as the polymerization catalyst, polymerization process, and polymerization temperature, are equivalent, the molecular structure will be equivalent to that of an ethylene-α-olefin copolymer made from a fossil fuel-derived monomer. Therefore, the performance is also expected to be unchanged.

[Inorganic filler]
The propylene-based resin composition of the present invention may further contain an inorganic filler (hereinafter, sometimes referred to as "inorganic filler (D)") from the viewpoint of improving mechanical properties, dimensional stability, and the like.

Inorganic fillers (D) include (i) fibrous inorganic fillers and (ii) non-fibrous inorganic fillers. In the present invention, two or more types of inorganic fillers (D) may be used in combination. Specific examples are described below.

<(i) Fibrous Inorganic Filler>
In the present invention, the fibrous inorganic filler preferably has an average fiber diameter of 0.2 to 20 μm, an average fiber length of 5 to 200 μm, and an aspect ratio of 10 to 30. From the viewpoint of improving the rigidity and appearance of the molded article, it is more preferable that the average fiber diameter is 0.3 to 10 μm, the average fiber length is 7 to 150 μm, and the aspect ratio is 12 to 25.

The average fiber diameter and average fiber length of a fibrous inorganic filler are the average values of the fiber diameter and fiber length measured by randomly selecting 50 or more fibers from an image of the fibrous inorganic filler obtained, for example, by electron microscopy, and the aspect ratio can be calculated using these average values.

Fiber-like inorganic fillers include fibrous magnesium oxysulfate, potassium titanate fiber, magnesium hydroxide fiber, aluminum borate fiber, calcium silicate fiber, calcium carbonate fiber, carbon fiber, glass fiber, and metal fiber. Of these, it is preferable to use fibrous magnesium oxysulfate and calcium silicate fiber.

The fibrous inorganic filler can be used as is. From the perspective of improving interfacial adhesion and further improving dispersibility, the fibrous inorganic filler may be further surface-treated with, for example, a silane coupling agent or a metal salt of a higher fatty acid.

Examples of higher fatty acid metal salts that can be used for surface treatment include calcium stearate, magnesium stearate, and zinc stearate.

In the present invention, the fibrous inorganic filler may be in the form of powder, flakes, or granules. Any of the above forms of fibrous inorganic filler may be used in the present invention. Because of its ease of handling, it is preferable to use a fibrous inorganic filler in the form of granules.

<(ii) Non-fibrous inorganic filler>
Examples of non-fibrous inorganic fillers include talc, mica, calcium carbonate, barium sulfate, magnesium carbonate, clay, alumina, calcium sulfate, silica sand, carbon black, titanium oxide, magnesium hydroxide, molybdenum, diatomaceous earth, sericite, shirasu, calcium hydroxide, calcium sulfite, sodium sulfate, bentonite, graphite, etc. From the viewpoints of improving the impact strength and appearance of the molded article, it is preferable to use talc.

The average particle diameter of the non-fibrous inorganic filler is preferably 15 μm or less, and more preferably 10 μm or less. Here, the average particle diameter of the non-fibrous inorganic filler is determined based on volumetric particle size distribution measurement data measured by laser diffraction in accordance with the method specified in JIS R1629, and refers to the particle diameter when the cumulative number of particles from the smallest particle size reaches 50% in the particle size distribution measurement data (50% equivalent particle diameter). A particle diameter defined in this way is generally referred to as the "50% equivalent particle diameter" and is expressed as "D50."

Non-fibrous inorganic fillers can be used as is. To improve interfacial adhesion and dispersibility, the surface of the non-fibrous inorganic filler may be treated with a silane coupling agent, titanium coupling agent, or surfactant before use.

Surfactants that can be used for surface treatment include, for example, higher fatty acids, higher fatty acid esters, higher fatty acid amides, and higher fatty acid salts.

The content of the inorganic filler in the polyolefin resin composition is preferably 1 part by mass or more and 40 parts by mass or less, more preferably 5 parts by mass or more and 35 parts by mass or less, and even more preferably 5 parts by mass or more and 30 parts by mass or less, when the total amount of the propylene resin composition is 100 parts by mass.

[Other additives]
The propylene-based resin composition of the present invention may contain, in addition to the components already described above, various other additives (hereinafter, sometimes referred to as “other additives (E)”) as further optional components.

Other additives (E) include, for example, antioxidants, neutralizing agents, ultraviolet absorbers, light stabilizers, lubricants, antistatic agents, colorants (e.g., inorganic pigments, organic pigments), flame retardants, elastomers, antiblocking agents, processing aids, organic peroxides, pigment dispersants, foaming agents, foam nucleating agents, plasticizers, crosslinking agents, crosslinking aids, brightness enhancers, antibacterial agents, light diffusing agents, and molecular weight modifiers.

The propylene-based resin composition of the present invention may contain one of these additives alone, or two or more optional components in any combination and ratio.

Among the other additives (E), antioxidants, neutralizing agents, UV absorbers, light stabilizers, and colorants are preferably used. The propylene-based resin composition of the present invention preferably contains, in addition to the above components, one or more selected from the group consisting of organic peroxides, neutralizing agents, antioxidants, UV absorbers, light stabilizers, and colorants.

The propylene-based resin composition may contain, as an additive other than the additives already described, a polymer such as a resin or rubber (excluding the propylene-based polymer (A) and the ethylene-α-olefin copolymer (C)).
Examples of such polymers include polystyrenes (e.g., polystyrene, poly(p-methylstyrene), poly(α-methylstyrene), AS (acrylonitrile/styrene copolymer) resin), ABS (acrylonitrile/butadiene/styrene copolymer) resin, AAS (special acrylic rubber/acrylonitrile/styrene copolymer) resin, ACS (acrylonitrile/chlorinated polyethylene/styrene copolymer) resin, polychloroprene, chlorinated rubber, polyvinyl chloride, polyvinylidene chloride, (meth)acrylic resin, ethylene/vinyl alcohol copolymer resin, fluororesin, polyacetal, grafted polyphenylene ether resin, and polyphenylene sulfide resin. Examples of suitable resins include thermoplastic resins such as polyurethane, polyamide, polyester resin (e.g., polyethylene terephthalate, polybutylene terephthalate), polycarbonate, polysulfone, polyether ether ketone, polyether sulfone, and aromatic polyester resin, epoxy resin, diallyl phthalate prepolymer, silicone resin, silicone rubber, polybutadiene, 1,2-polybutadiene, polyisoprene, styrene/butadiene copolymer, butadiene/acrylonitrile copolymer, epichlorohydrin rubber, (meth)acrylic rubber, and natural rubber, as well as PLA resin (polylactic acid) produced by polymerizing plant-derived monomers extracted from biomaterials.
In the present invention and this specification, the term "(meth)acrylic resin" refers to either or both of an acrylic resin and a methacrylic resin. The same applies to "(meth)acrylic rubber."

[Method for producing propylene-based resin composition]
The propylene-based resin composition of the present invention can be produced by a known method, and can usually be produced by melt-kneading the components already described. The order in which the components are kneaded is not particularly limited. For example, all of the components may be charged into a melt-kneading device at once and kneaded, or a mixture obtained by kneading some of the components may be kneaded with the remaining components.
Here, the timing of propanol mixing is not particularly limited, but it is usually mixed with the propylene polymer (A) or the like before or during melt-kneading. At this time, the propanol content in the propylene resin composition can be set within the above range by appropriate means, taking into account the melt-kneading conditions. Typically, a propylene resin composition is prepared by melt-kneading a large amount of propanol with the propylene polymer (A) or the like under melt-kneading conditions set in consideration of the amount of propanol volatilizing during melt-kneading, while adjusting the propanol content. The amount of propanol volatilizing during melt-kneading (the propanol content in the propylene resin composition) can be adjusted by, for example, setting the amount of propanol mixed, the amount of opening or closing of the vent line (gas vent) of the melt-kneader, the kneading temperature, the kneading time, etc. The amount of propanol volatilizing during melt-kneading can be adjusted using the results of preliminary experiments or a calibration curve prepared in advance. When the propanol content falls within the above range through melt mixing under normal conditions, there is no need to adjust the amount of propanol volatilized.

The melt-kneading temperature is not particularly limited and is determined appropriately, taking into consideration factors such as the amount of propanol that volatilizes. The melt-kneading temperature is usually set to 180°C or higher, and can be set to 180-300°C, or can also be set to 180-250°C. The melt-kneading time is also not particularly limited and is determined appropriately, taking into consideration factors such as the amount of propanol that volatilizes.

A conventional melt-kneading device can be used as the melt-kneading device for producing the propylene-based resin composition of the present invention. Suitable melt-kneading devices include, for example, a Banbury mixer, a single-screw extruder, a twin-screw co-rotating extruder, and a twin-screw counter-rotating extruder. Specific examples of melt-kneading devices include ZSK (registered trademark) manufactured by Coperion, TEM (registered trademark) manufactured by Toshiba Machine Co., Ltd., TEX (registered trademark) manufactured by The Japan Steel Works, Ltd., KZW (registered trademark) manufactured by Technovel Co., Ltd., CMP (registered trademark) and TEX (registered trademark) manufactured by The Japan Steel Works, Ltd., FCM (registered trademark), NCM (registered trademark), and LCM (registered trademark) manufactured by Kobe Steel, Ltd., and the V-50-F600 film molding machine manufactured by Tanabe Plastics Machinery Co., Ltd.

[Characteristics of Propylene-Based Resin Composition]
The propylene-based resin composition of the present invention may have any properties as long as the propanol content falls within the above range, and other properties may be appropriately determined.
For example, the MFR (230°C, 2.16 kgf) of the propylene-based resin composition is not particularly limited and can be set appropriately. From the viewpoint of excellent processability (moldability), it is preferably 1 g/10 min or more, more preferably 5 g/10 min or more, even more preferably 10 g/10 min or more, particularly preferably 20 g/10 min or more, and most preferably 25 g/10 min or more. The upper limit of the MFR can be determined appropriately and can be, for example, 200 g/10 min or less, preferably 120 g/10 min or less, and more preferably 100 g/10 min or less.
When the propylene-based resin composition is used as a material for a film-shaped molded article, for example, the melt flow rate of the propylene-based resin composition is preferably less than 20 g/10 min, regardless of the above range. In this embodiment, the upper limit of the melt flow rate is preferably 15 g/10 min or less, more preferably 10 g/10 min or less. On the other hand, the lower limit of the melt flow rate is preferably 0.1 g/10 min or more, more preferably 0.5 g/10 min or more, and even more preferably 1.0 g/10 min or more.
The MFR of the propylene-based resin composition is a value measured under the above-mentioned conditions and method.

The SVM (Solvent Volatile Material) of a propylene-based resin composition is not particularly limited as long as the propanol content is within the above range, and can be set as appropriate. To further suppress odor generation from molded articles, the SVM of a propylene-based resin composition is preferably 200 ppm or less, more preferably 100 ppm by mass or less, and, in terms of standards set by European and American automobile manufacturers, preferably 50 ppm or less. The lower limit of the SVM is not particularly limited, and ideally is the same as the propanol content, but in practice it will be higher than the propanol content, for example, 10 ppm by mass or more. The SVM of a propylene-based resin composition includes propanol, and is the value measured using the method described in the Examples below.

In the present invention and this specification, the propylene-based resin composition of the present invention is not particularly limited in terms of its properties or form, as long as it contains a propylene-based polymer (A) and propanol (B) in a content of 0.01 to 30 ppm by mass. This includes unmolded products such as melt-kneaded mixtures of the components, for example, strands and pellets, as well as molded products. The pellet-like form is not particularly limited, and examples include granules and tablets. For example, a pellet-like form can be produced by preparing a strand-like propylene-based resin composition and then cutting it to an appropriate length. In the present invention and this specification, an "unmolded product" refers to a product that is not molded into a shape or size suitable for various applications and is used as a molding material, and a "molded product" refers to a product molded into a shape or size suitable for various applications.

[Molded body]
The molded article of the present invention is a molded article containing the above-mentioned propylene-based resin composition of the present invention, and is usually a molded article obtained by molding a molten mixture of the above components or the propylene-based resin composition of the present invention by a known molding method. The propanol content in the molten mixture of the above components is not particularly limited and can be appropriately determined taking into account the amount of volatilization during molding, and can also be set to a content higher than the content in the propylene-based resin composition of the present invention. The propylene-based resin composition of the present invention can be suitably used as a material for forming a molded article. The molded article of the present invention has excellent tensile modulus and suppressed odor generation.
The molded article can be molded simultaneously with or consecutively to the preparation (melt mixing) of the propylene-based resin composition of the present invention. Alternatively, after the preparation of the propylene-based resin composition of the present invention, the propylene-based resin composition can be molded by various molding methods. Known molding methods can be applied, such as press molding, extrusion molding, and injection molding. The molding conditions for each molding method are not particularly limited as long as the molten mixture of the components or the propylene-based resin composition of the present invention can be molded in a molten state. These conditions can be appropriately set depending on the composition and physical properties of the molten mixture of the components or the propylene-based resin composition of the present invention. The kneading method and kneading conditions (kneading temperature) used in the preparation of the propylene-based resin composition of the present invention can be preferably applied. When using the propylene-based resin composition of the present invention, since the propanol content in the propylene-based resin composition is set within the above-mentioned range, molding conditions that can suppress volatilization of propanol are preferred. For example, molding conditions may include closing the vent line or gas vent of the molding machine and setting the molding time (heating time) to a short time.

The shape and size of the molded product of the present invention are determined appropriately depending on the application. For example, the molded product of the present invention (its shape) may be a sheet (sheet-like molded product), a block (block-like molded product), or various three-dimensional shapes (three-dimensional molded products). Sheets (sheet-like molded products) include films (film-like molded products), strips (strip-like molded products), and plates (plate-like molded products), and may be long or short (leaf-like).

The molded article of the present invention may be a molded article consisting solely of a molded article of the propylene-based resin composition of the present invention, or may be a molded article consisting of the molded article in addition to other components. Examples of other components include a surface layer (coating layer), a colored layer, and a reinforcing layer. Furthermore, the molded article of the present invention may be subjected to surface treatments such as hard coating, water repellency, and antibacterial treatment, as needed.

[Characteristics of molded product]
The propanol content and SVM in the molded article of the present invention are not particularly limited, and when the propylene-based resin composition is molded, they are not unique and depend on the molding conditions, etc. The molded article of the present invention can be applied to the propanol content and SVM in the propylene-based resin composition of the present invention in that odor generation can be effectively suppressed, and it is preferable that the propanol content and SVM are on the same numerical order (numerical range) as these contents and SVM.

The tensile modulus, flexural modulus (FM), and Charpy impact strength of the molded article are not particularly limited and are not uniquely determined by the composition of the propylene-based resin composition (type and content of components), etc., but can be appropriately determined depending on the application, required properties, etc. The tensile modulus, flexural modulus (FM), and Charpy impact strength of the molded article (all measured by the methods described in the Examples below) can maintain the performance exhibited by a molded article formed from a propylene-based resin composition having the same composition except that it does not contain propanol, and for example, the tensile modulus of the molded article can be 500 to 2500 MPa, the flexural modulus of the molded article can be 500 to 2500 MPa, and the Charpy impact strength of the molded article can be 5 to 70 kJ/ ^m2 .

The indices and standards for evaluating the grip property, openability, and blocking strength stability of a sheet-like molded product are not particularly limited and are not uniquely determined by the composition (type and content of components) of the propylene-based resin composition, but can be appropriately determined depending on the application, required properties, etc. The evaluation of the grip property, openability, and blocking strength stability of a sheet-like molded product (all of which are evaluated using the methods and measurements described in the Examples below) can maintain the evaluation (performance) of a molded product formed from a propylene-based resin composition having the same composition except that it does not contain propanol. For example, the static friction coefficient, which is one index for evaluating the grip property of a sheet-like molded product, can be 0.98 to 1.10, and the heat seal strength, which is one index for evaluating the openability of a sheet-like molded product, can be 15.0 to 19.4 N/15 mm. Furthermore, the blocking strength standard deviation, which is one index for evaluating the blocking strength stability of a sheet-like molded product, can be 0.40 to 0.60 N/12 cm ² .

The propylene-based resin composition of the present invention can be used as a material for molded articles such as automobile parts (vehicle-related components), home appliances, monitors, office automation equipment, medical equipment, drain pans, toiletries, food packaging containers, bottles, containers, sheets, and films. The propylene-based resin composition and molded articles thereof exhibit excellent tensile modulus and suppressed odor generation. Therefore, the propylene-based resin composition of the present invention is particularly suitable for use as a material for molded articles closely related to daily life, and is particularly suitable for use as a material for vehicle-related components, home appliances, and food packaging containers such as retort pouches and microwaveable pouches. Molded articles obtained from the propylene-based resin composition of the present invention exhibit excellent tensile modulus, suppressed odor generation, and also excellent tensile modulus, flexural modulus (FM), and/or Charpy impact strength, making them suitable for use in the injection-molded articles described below. On the other hand, sheet-shaped molded articles obtained from the propylene-based resin composition of the present invention not only have a high tensile modulus and suppressed odor generation, but also have excellent gripping properties, ease of opening, and/or stable blocking strength, making them particularly suitable for use as packaging films, particularly food packaging (pouch) films or materials for such films.

The propylene-based resin composition of the present invention is particularly preferably used as a material for injection molding.
Hereinafter, an example will be described in which the molten mixture of the above components or the propylene-based resin composition of the present invention is used as an injection molding material to produce an injection-molded article.

Injection-molded articles are molded articles obtained by injection-molding a molten mixture of the above components or the propylene-based resin composition of the present invention. Injection-molded articles generally have excellent dimensional stability. Injection-molded articles can be produced by conventional injection molding methods. Examples of injection molding methods include injection foam molding, supercritical injection foam molding, ultra-high-speed injection molding, injection compression molding, gas-assisted injection molding, sandwich molding, sandwich foam molding, and insert-outsert molding.

The molded article (injection molded article) of the present invention can be produced by the above method in any suitable shape and dimensions depending on the application.

Among the above-mentioned uses, the injection-molded article is preferably used for vehicle-related components, home appliances, etc. Examples of vehicle-related components include interior parts such as door trims, pillars, instrument panels, consoles, rocker panels, armrests, door panels, and spare tire covers, exterior parts such as bumpers, spoilers, fenders, and side steps, as well as other parts such as air intake ducts, coolant reserve tanks, fender liners, fans, and under-deflectors, and integrally molded parts such as front-end panels.
Examples of home appliances include washing machines (outer tub, inner tub, lid, pulsator, balancer, etc.), dryers, vacuum cleaners, rice cookers, pots, warmers, dishwashers, and air purifiers.

The present invention will be explained in more detail below using examples. However, the present invention is not limited to these examples.

In the following explanation, "%" and "parts" used to represent quantities are by mass unless otherwise specified. Furthermore, the operations described below were carried out at room temperature and pressure unless otherwise specified.

[Methods for measuring physical properties]
(Melt Flow Rate)
Measurement was carried out in accordance with JIS K 7210-1:2014 and JIS K 7210-2:2014 under conditions of 230°C and a load of 2.16 kgf.

(intrinsic viscosity)
Using an Ubbelohde viscometer, the reduced viscosity was measured at multiple concentrations, the reduced viscosity was plotted against the concentration, and the intrinsic viscosity was determined by the "extrapolation method" in which the concentration was extrapolated to zero. More specifically, the intrinsic viscosity was determined by the method described on page 491 of "Polymer Solutions, Polymer Experiments 11" (published by Kyoritsu Publishing, 1982), in which the reduced viscosity was measured at three concentrations of 0.1 g/dL, 0.2 g/dL, and 0.5 g/dL, the reduced viscosity was plotted against the concentration, and the concentration was extrapolated to zero. Tetralin was used as the solvent, and the measurement temperature was 135°C.

[Components used in Examples and Comparative Examples]
The components used in the examples and comparative examples are shown below.

(1) Propylene-based polymer (A)
(Propylene-based polymer (A-1): heterophasic propylene polymer material)
A heterophasic propylene polymer material (A-1) was produced as a propylene polymer (A) by a liquid-phase-gas phase polymerization method using a polymerization catalyst obtained by the method described in Example 1 of JP 2004-182981 A, the heterophasic propylene polymer material (A-1) containing 79 parts by mass of (a) a propylene homopolymer component as a polymer (I) and 21 parts by mass of (b) a propylene-ethylene random copolymer component as a polymer (II).
The physical properties were as follows:
Melt flow rate (230°C, load 2.16 kgf): 28 g/10 min. (a) Propylene homopolymer component intrinsic viscosity: 1.06 dL/g.
Pentad fraction: 0.98
(b) Propylene-ethylene random copolymer Intrinsic viscosity: 2.8 dL/g
Content of structural units derived from ethylene: 33% by mass

(b) The content of ethylene-derived structural units in a propylene-ethylene random copolymer was determined from ^a C-NMR spectrum measured under the following conditions based on the report by Kakugo et al. (Macromolecules, 15, 1150-1152 (1982)). The ^C -NMR spectrum was measured under the following conditions using a sample prepared by uniformly dissolving about 200 mg of heterophasic propylene polymerization material (A-1) in 3 mL of ortho-dichlorobenzene in a test tube with a diameter of 10 mm.
Measurement temperature: 135℃
Pulse repetition time: 10 seconds Pulse width: 45°
Accumulation count: 2500 times

(Propylene-based polymer (A-2): heterophasic propylene polymer material)
A heterophasic propylene polymer material (A-2) was produced as a propylene polymer (A) by a liquid-phase-gas phase polymerization method using a polymerization catalyst obtained by the method described in Example 1 of JP 2004-182981 A, the heterophasic propylene polymer material (A-2) containing 77 parts by mass of (a) a propylene homopolymer component as a polymer (I) and 23 parts by mass of (b) a propylene-ethylene random copolymer component as a polymer (II).
The physical properties were as follows:
Melt flow rate (230°C, load 2.16 kgf): 2.8 g/10 min. (a) Propylene homopolymer component intrinsic viscosity: 1.77 dL/g.
Pentad fraction: 0.97
(b) Propylene-ethylene random copolymer Intrinsic viscosity: 3.2 dL/g
Content of structural units derived from ethylene: 30% by mass
The content of the ethylene-derived structural units in the propylene-ethylene random copolymer (b) was determined in the same manner as in the propylene polymer (A-1).

(Propylene-based polymer (A-3): propylene-based multistage polymer)
Using a Ziegler-Natta catalyst, in the first step, propylene and ethylene were copolymerized in a liquid phase, and then in the second step, propylene and 1-butene were copolymerized in a gas phase, resulting in a propylene-based multistage polymer consisting of a propylene-ethylene random copolymer (I) (corresponding to the above-mentioned propylene-based random copolymer (1)) prepared in the first polymerization step and a propylene-1-butene random copolymer (II) (corresponding to the above-mentioned propylene-based random copolymer (2)) prepared in the second polymerization step. The content of structural units derived from ethylene in the propylene-ethylene copolymer (I) was 4% by mass, and the content of structural units derived from 1-butene in the propylene-1-butene copolymer (II) was 25% by mass. The resulting propylene-based multistage polymer had a propylene-ethylene random copolymer (I) content of 19% by mass and a propylene-1-butene random copolymer (II) content of 81% by mass, and copolymer (I) and copolymer (II) were compatible. The melt flow rate (230°C, load 2.16 kgf) was 1.2 g/10 min. The intrinsic viscosity of copolymer (I) was 3.1 dL/g, and the intrinsic viscosity of copolymer (II) was 2.2 dL/g.
The content of structural units derived from ethylene in copolymer (I) was determined in the same manner as for the propylene-based polymer (A-1). The content of structural units derived from 1-butene in copolymer (II) was determined based on the intensity ratio of the spectral intensity of methyl carbon derived from propylene to the spectral intensity of methyl carbon derived from 1-butene from ^a C-NMR spectrum measured in the same manner as for the propylene-based polymer (A-1).

(2) 2-propanol (B)
As 2-propanol (B-1), IPA (CAS No. 67-63-0, "Special Grade 2-Propanol" manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was prepared.
As 2-propanol (B-2), IPA (CAS No. 67-63-0, Junsei Chemical Co., Ltd. "Special Grade Reagent 2-Propanol") was prepared.

(3) Other Additives (3-1) Neutralizing Agent Calcium stearate (CAS No. 1592-23-0, manufactured by Sakai Chemical Industry Co., Ltd., calcium stearate) was prepared.
(3-2) Antioxidant Antioxidant 1 (CAS No. 6683-19-8, "Irganox 1010" (trade name) manufactured by BASF) was prepared.
An antioxidant 2 (CAS No. 31570-04-4, "Irgafos 168" (trade name) manufactured by BASF) was prepared.

[evaluation]
(1) Odor Measurement Method Each PP pellet prepared in the Examples and Comparative Examples was fed into an injection molding machine (Meiki Seisakusho "M70 Type Injection Molding Machine"), and flat plates (multiple plates) of the resin composition, measuring 60 mm in length, 60 mm in width, and 2.0 mm in thickness, were molded under the following conditions: molten resin temperature 200°C, mold temperature 40°C, filling pressure 15 MPa, dwell pressure 4.3 MPa, dwell time 40 seconds, total cycle time 60 seconds, and molded product removal temperature 60°C or less. Note that the vent line was not particularly clogged during the melting of the PP pellets. The flat plates were then cut to a size of 60 mm in length, 30 mm in width, and 2.0 mm in thickness.
A total of three of these cut flat plates were placed in a 0.5 L odorless glass bottle, the lid was closed, and the bottle was heated in an oven at 80° C. for two hours. The three flat plates were arranged so that the main surfaces of each plate were not in close contact with the inner surface of the glass bottle or the main surfaces of the other flat plates.
Thereafter, the glass bottle was left to stand for a while at 60° C. Then, three or more panelists evaluated the odor of the plates in the glass bottle without removing the three plates.
The panelists scored the odor level based on the following criteria.

1 point: No odor 2 points: Odor is noticeable 3 points: Strong odor is noticeable

The scores given by all panelists were totaled and divided by the number of panelists to calculate an average odor score. The level of odor of the flat plates of the Examples and Comparative Examples was evaluated based on this average score. The lower the average odor score, the less odor there was, and a score of 2.5 or less was deemed acceptable, as it would not cause strong discomfort in practical use.
The panelists also recorded the quality of the odors they perceived, including solvent odors, chemical odors, alcohol odors, amine odors, sulfur odors, and fishy odors.

(2) Measurement of IPA Amount (2-1) Examples 1 and 2 and Comparative Examples 1 and 2
The amount of IPA was measured by gas chromatography (GC) according to the following procedure.
Specifically, a gas chromatograph GC-14A (manufactured by Shimadzu Corporation) was used as the apparatus, and a capillary DB-Wax-0.53Φ 60 m (strong polarity column) was used as the column.
A flame ionization detector (FID) was used as the detector, and helium was used as the carrier gas.
1 g of the PP pellets used for the measurement was weighed and sealed in a 20 mL vial. The vial was heated at 120°C for 1 hour, and 0.5 mL of the sample gas evaporated into the vial was collected using a syringe and measured by GC-FID.
The GC measurement conditions were an injection port temperature of 200°C, an FID detector temperature of 230°C, and a column oven temperature of 40°C, which was held for 0 seconds, heated from 40°C to 100°C at 1.5°C/min, and heated from 100°C to 230°C at 15°C/min. The temperature was held at 230°C for 60 seconds. A splitless system was used to detect even trace amounts of propanol.
The IPA content was quantified by converting the total volatile components into the amount of n-heptane using a one-point calibration curve for n-heptane. 1 μL of n-heptane was collected in a 20 mL vial and heated at 120°C for 1 hour. 0.5 mL of the sample gas evaporated into the vial was collected and measured by GC-FID. The measurement conditions were the same as above. After the measurement, the area intensity of the peak corresponding to IPA was quantified based on the amount of n-heptane. In addition to the PP pellets, a total of 1 g of a portion was cut from the flat plate molded in (1), and the IPA content was measured and quantified using the same method.

(2-2) Examples 3 to 6 and Comparative Examples 3 to 6
The amount of IPA was measured by gas chromatography (GC) according to the following procedure. Specifically, a 7890 GC system (manufactured by Agilent Technologies) was used as the apparatus, and a J&W DB-Waxetr, 30 m x 0.25 mm i.d., film thickness 0.25 μm (manufactured by Agilent Technologies) was used as the column. A flame ionization detector (FID) was used as the detector, and helium was used as the carrier gas.
1 g of the PP pellets used for the measurement was weighed and sealed in a 22 mL vial. Using a headspace sampler HS40 (manufactured by PerkinElmer), the vial was heated at 120°C for 1 hour, and the sample gas evaporated into the vial was collected over a sampling time of 0.05 minutes and measured by GC-FID.
The GC measurement conditions were an injection port temperature of 200°C, an FID detector temperature of 230°C, and a column oven temperature of 40°C, which was held for 0 seconds, heated from 40°C to 100°C at 1.5°C/min, and heated from 100°C to 230°C at 15°C/min. The temperature was held at 230°C for 60 seconds. The split ratio was 10:1.
The amount of IPA was quantified by converting all volatile components into the amount of n-heptane using a one-point calibration curve for n-heptane. 10 μL of n-heptane was collected in a 22 mL vial, and an HS40 (manufactured by PerkinElmer) was used as a headspace sampler. The vial was heated at 120°C for 1 hour, and the sample gas volatilized in the vial was collected under a sampling time of 0.05 minutes and measured by GC-FID. The measurement conditions were the same as above. After the measurement, the area intensity of the peak corresponding to IPA was quantified based on the amount of n-heptane.
For a propylene-based resin composition in which two types of PP pellets were mixed, the detected amount of the resin composition was determined as the sum of the values obtained by multiplying the detected amount in each PP pellet by the blending ratio.

(3) Measurement of SVM: Amount of Solvent Volatile Material Measurement and quantification of the amount of SVM were carried out in the same manner as for the amount of IPA. The sum of the area intensities of all peaks detected within 20 minutes from the start of measurement was quantified based on the amount of n-heptane.

(4) Tensile Modulus Each PP pellet prepared in the Examples and Comparative Examples was fed into an injection molding machine (Meiki Seisakusho "M70 Type Injection Molding Machine"), and a dumbbell-shaped test piece was molded under the following conditions: molten resin temperature 200 ° C, mold temperature 40 ° C, filling pressure 15 MPa, dwell pressure 4.3 MPa, dwell time 40 seconds, total cycle time 60 seconds, and molded product removal temperature 60 ° C or less. Note that the vent line was not particularly clogged during melting of the PP pellets. Two days after molding, the tensile modulus was measured using a dumbbell-shaped test piece under conditions of 23 ° C and 50% RH in accordance with JIS K 7161-2:2014.

(5) Flexural modulus: FM
The above dumbbell-shaped test piece was cut into a shape with a total length of 80 mm, a width of 10 mm and a thickness of 4 mm, and the measurement was carried out in accordance with JIS K7171.

(6) Charpy impact strength: Charpy
The dumbbell-shaped test piece was cut into a shape with a total length of 80 mm, a width of 10 mm, and a thickness of 4 mm, and further V-notched on the surface defined by the total length of 80 mm and the thickness of 4 mm. Measurement was carried out in accordance with JIS K 7111-1.

(7) Surface Resistivity Each PP pellet prepared in the Examples and Comparative Examples was fed to a Sumitomo Heavy Industries, Ltd. "SE130 Type Molding Machine" and molded into a flat plate with a length of 150 mm, a width of 90 mm, and a thickness of 3.0 mm at a molding temperature of 220°C, a mold cooling temperature of 50°C, and a pressure of 50 MPa. The vent line was not particularly clogged during melting of the PP pellets. Seven days after molding, the surface resistivity was measured in accordance with JIS K 6911 using a HIOKI SM7110 (manufactured by Hioki E.E. Corporation) under conditions of 23°C and 50% RH.

(8) Static Friction Coefficient of Film Each PP pellet prepared in the Examples and Comparative Examples was supplied to a 50 mm T-die film-forming device (Tanabe Plastics Machinery Co., Ltd., V-50-F600 type film-forming device, equipped with a 400 mm wide T-die, without a vacuum vent line), and melt-extruded at a molten resin temperature of 250°C. Then, the pellets were cooled and solidified while being wound up on a chill roll through which 50°C cooling water was passed, to obtain a film having a thickness of 70 μm.
From the obtained film, several test pieces of MD 100 mm × TD 50 mm were cut out, and the chill roll surfaces of two test pieces were overlapped at room temperature of 23 ° C. and humidity of 50%. Measurements were carried out using a Toyo Seiki friction measuring instrument (TR-2 type) under the conditions of a contact surface of 40 mm × 40 mm, a measurement load of 79.4 g, and a moving speed of 15 cm / min. Measurements were carried out six times and the average value was calculated. A higher static friction coefficient is preferable because the film has a higher grip.

(9) Heat seal strength of film (unit: N/15 mm)
The surfaces (chill roll surfaces) of the films prepared with the static friction coefficient of the film (8) above were overlapped and heat-sealed by pressing them together for ¹ second with a heat sealer (manufactured by Toyo Seiki) heated to 140°C or 185°C under a load of 1 kg/cm2. The sample was then conditioned at 23°C and 50% humidity, and the peel resistance when peeled at 23°C, 50% humidity, and a peel angle of 180° was determined as the heat seal strength. Measurements were performed six times and the average value was calculated. An excessively high heat seal strength is undesirable because it deteriorates the ease of opening the packaging bag.

(10) Standard deviation of film blocking strength (unit: N/12 cm ² )
A test piece measuring 150 mm in MD x 30 mm in TD was cut from the film prepared according to the static friction coefficient of the film (8) above. Two films were stacked together with the surfaces opposite the chill roll in contact, and a 500 g load was applied to a 40 mm x 30 mm area, followed by conditioning at 80°C for 24 hours. The stacked multilayer film was then left for 30 minutes or more in an atmosphere of 23°C and 50% humidity, and the strength required for peeling the multilayer film (i.e., blocking strength) was measured using a tensile tester at a rate of 200 mm/min. The measurement was performed six times, and the standard deviation was calculated. A lower standard deviation of the blocking strength is preferable because the blocking strength is more stable.

[Examples 1 and 2 and Comparative Examples 1 and 2]
The components listed in Table 1 below were weighed out in the blending ratios listed in the table and uniformly mixed at 23°C. The resulting mixture was then fed into the most upstream raw material inlet of a twin-screw kneader (twin-screw extruder, "TEX44αII" (trade name) manufactured by Japan Steel Works, Ltd.) and melt-kneaded to obtain pellets of a propylene-based resin composition (also referred to as "PP pellets"). The melt-kneading conditions were a cylinder temperature of 200°C, a discharge rate of 50 kg/h, a screw rotation speed of 200 rpm, and an oxygen concentration of 2% in the feed hopper. The oxygen concentration in the feed hopper was measured by inserting a sensor equipped with a portable oxygen concentration meter into the purge resin inlet attached to the feed hopper. The 2% oxygen concentration condition was achieved by flowing nitrogen gas through the feed hopper. The vacuum vent line attached to the twin-screw kneader was closed to prevent volatilization of IPA.

The resulting propylene-based resin composition pellets (PP pellets) were used to measure or evaluate the following using the evaluation methods described above: (1) odor measurement, (2-1) IPA measurement (quantitative), (3) SVM measurement (quantitative), MFR, (4) tensile modulus, (5) flexural modulus (FM), (6) Charpy impact strength (Charpy), and (7) surface resistivity.

[Formulation of Propylene-Based Resin Composition and Evaluation Results]
The blending amounts (unit: parts by mass) of the propylene-based resin compositions are shown in Table 1 below, and the evaluation results are shown in Tables 2 and 3 below.
In Table 1, the abbreviations have the following meanings.
"A-1": Propylene polymer (A-1) (heterophasic propylene polymer material)
"CaSt2": calcium stearate "Irg1010": "Irganox 1010" (trade name, manufactured by BASF)
"Irg168": "Irgafos168" (product name, manufactured by BASF)
"IPA": "IPA (B-1)" (special grade 2-Propanol, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.)

As is clear from the results shown in Tables 1 to 3, propylene-based resin compositions that do not contain a specific amount of propanol cannot form molded articles that satisfy both a high tensile modulus and odor suppression. Specifically, the propylene-based resin composition of Comparative Example 1, which does not contain propanol, cannot suppress odor generation, and the molded articles emit a pungent, strong odor. On the other hand, the propylene-based resin composition of Comparative Example 2, which contains an excessive amount of propanol (the detected amount of IPA shown in Table 2), has a molded article that is inferior in tensile modulus.
In contrast, the propylene-based resin compositions of Examples 1 and 2, which contain propanol in the range of 0.01 to 30 ppm by mass (detectable IPA amounts shown in Table 2), were able to produce molded articles that suppress odor generation while maintaining excellent tensile modulus. Furthermore, with regard to surface resistivity (insulating properties), flexural modulus (FM), and Charpy impact strength (Charpy), the flexural modulus showed values similar to those of the molded article formed with a conventional propylene-based resin composition (Comparative Example 1), while the Charpy impact strength (Charpy) and insulating properties showed values superior to those of the molded article formed with the conventional propylene-based resin composition (Comparative Example 1), demonstrating excellent performance in these properties as well. Thus, the propylene-based resin composition of the present invention is able to achieve both excellent tensile modulus and suppression of odor generation, and can produce molded articles that also exhibit excellent insulating properties, flexural modulus, and Charpy impact strength.

[Examples 3 to 6 and Comparative Examples 3 to 6]
The components listed in Table 4 below were weighed out in the blending ratios listed in the same table. Next, the components other than IPA were mixed, and the resulting mixture and IPA were charged into a single-screw kneader (single-screw extruder, Tanabe Plastic Machinery Co., Ltd., VS40-28 type, with a full-flight screw, without a vacuum vent line) through the most upstream raw material inlet and melt-kneaded to obtain propylene-based resin composition pellets A-2a, A-2b, A-3a, and A-3b, respectively. The melt-kneading conditions were a cylinder temperature of 200°C, a discharge rate of 13 kg/hour, and a screw rotation speed of 100 rpm.

Propylene-based resin composition pellets (also referred to as "PP pellets") were prepared by mixing the resulting pellets A-2a, A-2b, A-3a, and A-3b in the ratios shown in Tables 5 and 6. Using the resulting propylene-based resin composition pellets (PP pellets), the following were measured or evaluated using the evaluation methods described above: (2-2) IPA measurement (quantitative), MFR, (8) film static friction coefficient, (9) heat seal strength when heat-sealed using a heat sealer set to 140°C or 185°C, and (10) film blocking strength standard deviation.

[Formulation of Propylene-Based Resin Composition and Evaluation Results]
The blending amount (unit: parts by mass) of each propylene-based resin composition is shown in Table 4 below, and the evaluation results are shown in Tables 4 to 6 below.
In Table 4, the abbreviations have the following meanings.
"A-2": Propylene polymer (A-2) (heterophasic propylene polymer material)
"A-3": Propylene polymer (A-3) (propylene multistage polymer)
"CaSt2": calcium stearate "Irg1010": "Irganox 1010" (trade name, manufactured by BASF)
"Irg168": "Irgafos168" (product name, manufactured by BASF)
"IPA": "IPA (B-2)" (special grade 2-Propanol, Junsei Chemical Co., Ltd.)
In Table 5, "A-2a" and "A-2b" refer to "PP pellet A-2a" and "PP pellet A-2b" in Table 4, respectively, and in Table 6, "A-3a" and "A-3b" refer to "PP pellet A-3a" and "PP pellet A-3b" in Table 4, respectively.

When considering the results shown in Tables 4 to 6 in conjunction with the results shown in Tables 1 to 3, it can be seen that none of the propylene-based resin compositions (Comparative Examples 3 to 6) that do not contain a specific amount of propanol are able to form molded articles that achieve both a high tensile modulus and odor suppression. In contrast, the propylene-based resin compositions of Examples 3 to 6 that contain propanol in the range of 0.01 to 30 ppm by mass (detectable IPA amounts shown in Tables 5 and 6) are able to produce molded articles that can suppress odor generation while maintaining an excellent tensile modulus.

It can be seen that the propylene-based resin compositions containing an excess amount of propanol (Comparative Examples 4 and 6) have too high a heat seal strength, resulting in poor openability when used as packaging bags, and the standard deviation of the blocking strength is too high, resulting in poor stability (reproducibility) of the blocking strength. It can also be seen that the propylene-based resin composition containing a heterophasic propylene polymerization material but not containing propanol (Comparative Example 3) tends to have a low heat seal strength. It can also be seen that the propylene-based resin composition containing a random copolymer but not containing propanol (Comparative Example 5) suffers from substrate tearing, resulting in poor openability when used as packaging bags.
In contrast, when the propylene-based resin compositions of Examples 3 to 6 were molded into films, they exhibited high static friction coefficients and excellent grip strength. Furthermore, the heat seal strength and standard deviation of blocking strength when the propylene-based resin compositions of Examples 3 to 6 were molded into films tended to be smaller than the heat seal strength and standard deviation of blocking strength when the propylene-based resin compositions of Comparative Example 4 or Comparative Example 6 were molded into films, demonstrating excellent openability and stability (reproducibility) of blocking strength when used in packaging bags. Thus, the propylene-based resin composition of the present invention can realize a molded product (film) that exhibits excellent grip property, openability, and stability of blocking strength while simultaneously achieving excellent tensile modulus and odor suppression.

These results demonstrate that the propylene-based resin compositions of Examples 1 to 6, which contain propanol in the range of 0.01 to 30 ppm by mass, can all produce molded articles that suppress odor generation while maintaining an excellent tensile modulus. Furthermore, when molded into articles, the propylene-based resin compositions of Examples 1 to 6 exhibit excellent insulation properties, flexural modulus, and Charpy impact strength. Furthermore, when molded into sheet-like articles, the propylene-based resin compositions of Examples 1 to 6 can also achieve excellent levels of gripping properties, opening properties, and/or blocking strength stability, which may be appropriately required of sheet-like molded articles depending on the application, etc.

Claims (15)

A propylene-based resin composition containing a propylene-based polymer and propanol,
The propylene-based resin composition has a propanol content of 0.01 to 30 ppm by mass when the total mass of the propylene-based resin composition is 100 parts by mass. The propylene-based resin composition according to claim 1, wherein the propanol includes 2-propanol. The propylene-based resin composition according to claim 1 or 2, wherein the content of the propylene-based polymer is 50 parts by mass or more, relative to 100 parts by mass of the total mass of the propylene-based resin composition. The propylene-based resin composition according to claim 1 or 2, further comprising an ethylene-α-olefin copolymer. The propylene-based resin composition according to claim 4, wherein the content of the ethylene-α-olefin copolymer is 1 to 40 parts by mass, based on 100 parts by mass of the propylene-based resin composition. The propylene-based resin composition according to claim 1 or 2, further comprising an inorganic filler. The propylene-based resin composition according to claim 6, wherein the content of the inorganic filler is 1 to 40 parts by mass, relative to 100 parts by mass of the total mass of the propylene-based resin composition. The propylene-based resin composition according to claim 1 or 2, further comprising an ethylene-α-olefin copolymer and an inorganic filler. The propylene-based resin composition according to claim 8, wherein the content of the ethylene-α-olefin copolymer is 1 to 40 parts by mass, and the content of the inorganic filler is 1 to 40 parts by mass, when the total mass of the propylene-based resin composition is 100 parts by mass. The propylene-based resin composition according to claim 1 or 2, having an MFR (230°C, 2.16 kgf) of less than 20 g/10 min. The propylene-based resin composition according to claim 1 or 2, wherein the propylene-based polymer comprises a heterophasic propylene polymer material. The propylene-based resin composition according to claim 1 or 2, wherein the propylene-based polymer comprises a propylene-based random copolymer. The propylene-based resin composition according to claim 12, wherein the propylene-based random copolymer comprises a propylene-butene random copolymer. A molded article comprising the propylene-based resin composition according to claim 1 or 2. The molded article according to claim 14, which is a film.