JP7818902B2 - Propylene-based resin composition and its uses - Google Patents

Description

The present invention relates to a propylene-based resin composition, an adhesive resin composition, pellets, a molded article, a non-oriented film, a sheet, an injection-molded article, a blow-molded article, and an automobile part.

In recent years, propylene-based resin compositions, primarily composed of polypropylene-based polymers, have become known as polyolefin materials that offer excellent heat resistance, transparency, and other properties, as well as environmental friendliness and hygiene.

While the applications of such propylene-based resin compositions are currently expanding, the performance of the propylene-based resin compositions currently in use is insufficient, and there is room for improvement in terms of, for example, tensile strength and resistance to whitening during molding processing.

Patent Document 1 describes that a specific copolymer of propylene and an α-olefin having 5 or more carbon atoms has a certain level of tensile strength and does not whiten upon bending.

Japanese Patent Application Laid-Open No. 2000-7731

However, the propylene-based resin compositions using conventional propylene-based polymers such as those described in Patent Document 1 have room for improvement in terms of the balance between flexibility, tensile strength, and whitening resistance.
The present invention has been made in view of the above, and an object of the present invention is to provide a propylene-based resin composition which is excellent in balance among flexibility, tensile strength and whitening resistance.

A configuration example of the present invention is as follows.
In this specification, the numerical range "A to B" indicates A or more and B or less.

[1] 1 to 99% by mass of a propylene-α-olefin copolymer (A) satisfying the following requirements (I) to (IV):
A propylene-based resin composition comprising 1 to 99% by mass of a propylene-based polymer (B) other than the copolymer (A), the propylene-based polymer (B) having an MFR of 0.1 to 500 g/10 min at 230°C under a load of 2.16 kg, as measured in accordance with ASTM D1238E (where the total of the copolymer (A) and the polymer (B) is taken as 100% by mass).
(I) When the total of the structural unit (i) derived from propylene and the structural unit (ii) derived from an α-olefin having 5 to 20 carbon atoms is taken as 100 mol %, the content of the structural unit (i) is 75 to 95 mol %, and the content of the structural unit (ii) is 5 to 25 mol %. (II) The melting point measured by differential scanning calorimetry (DSC) is 95°C or less, or is not observed. (III) The isotactic triad fraction measured by ^13C -NMR is 85% or more. (IV) The intrinsic viscosity [η] measured in decalin at 135°C is 0.5 to 10 dl/g.

[2] The propylene-based resin composition according to [1], wherein the copolymer (A) has an isotactic triad fraction of 90% or more as measured by ¹³ C-NMR.

[3] The propylene-based resin composition according to [1] or [2], wherein the copolymer (A) has an MFR of 0.1 to 30 g/10 min under a load of 2.16 kg at 230°C, as measured in accordance with ASTM D1238E.

[4] The propylene-based resin composition according to any one of [1] to [3], wherein the α-olefin having 5 to 20 carbon atoms in the copolymer (A) is at least one selected from 1-hexene, 1-octene, 1-decene, and 1-dodecene.

[5] An adhesive resin composition comprising the propylene-based resin composition according to any one of [1] to [4].
[6] Pellets containing the propylene-based resin composition according to any one of [1] to [4] or the adhesive resin composition according to [5].
[7] A molded article comprising the propylene-based resin composition according to any one of [1] to [4] or the adhesive resin composition according to [5].
[8] A non-stretched film comprising the propylene-based resin composition according to any one of [1] to [4] or the adhesive resin composition according to [5].
[9] A sheet comprising the propylene-based resin composition according to any one of [1] to [4] or the adhesive resin composition according to [5].
[10] An injection-molded article comprising the propylene-based resin composition according to any one of [1] to [4] or the adhesive resin composition according to [5].
[11] A blow-molded article comprising the propylene-based resin composition according to any one of [1] to [4] or the adhesive resin composition according to [5].
[12] An automobile part selected from an interior part and an exterior part, comprising the propylene-based resin composition according to any one of [1] to [4] or the adhesive resin composition according to [5].

According to the present invention, it is possible to easily obtain a composition (molded article) that has an excellent balance of flexibility, tensile strength, and whitening resistance.

<Propylene-based resin composition>
The propylene-based resin composition according to the present invention (hereinafter also referred to as "the composition") comprises 1 to 99 mass % of a propylene/α-olefin copolymer (A) satisfying the following requirements (I) to (IV):
The composition contains 1 to 99% by mass of a propylene polymer (B) other than the copolymer (A), which has an MFR of 0.1 to 500 g/10 min at 230°C under a load of 2.16 kg as measured in accordance with ASTM D1238E (where the total of the copolymer (A) and the polymer (B) is taken as 100% by mass).

The breaking stress of the present composition is preferably 10 MPa or more, more preferably 20 MPa or more, even more preferably 25 MPa or more, and particularly preferably 30 MPa or more.
Specifically, the breaking stress is measured by the method described in the examples below.

The Shore D hardness (instantaneous value) of the present composition is preferably 30 to 80, more preferably 32 to 78.
The Shore D hardness (instantaneous value) is specifically measured by the method described in the examples below.

<Propylene/α-olefin copolymer (A)>
The propylene/α-olefin copolymer (A) satisfies the following requirements (I) to (IV).
The copolymer (A) used in the present composition may be one type or two or more types.
(I) When the total of the structural unit (i) derived from propylene and the structural unit (ii) derived from an α-olefin having 5 to 20 carbon atoms is taken as 100 mol %, the content of the structural unit (i) is 75 to 95 mol %, and the content of the structural unit (ii) is 5 to 25 mol %. (II) The melting point measured by differential scanning calorimetry (DSC) is 95°C or lower, or is not observed. (III) The isotactic triad fraction (mm fraction) measured by ^13C -NMR is 85% or higher. (IV) The intrinsic viscosity [η] measured in decalin at 135°C is 0.5 to 10 dl/g.

The copolymer (A) is not particularly limited as long as it is a copolymer obtained using propylene and one or more α-olefins having 5 to 20 carbon atoms, but it is preferably a random copolymer.

The content of the structural unit (i) is 75 to 95 mol %, preferably 80 to 95 mol %, and more preferably 85 to 95 mol %.
The content of the structural unit (ii) is 5 to 25 mol %, preferably 5 to 20 mol %, and more preferably 5 to 15 mol %.
The content of each of the structural units (i) and (ii) is the content when the total of the structural units (i) and (ii) is taken as 100 mol %.

When the contents of the structural units (i) and (ii) are within the above ranges, a composition (molded article) having a good balance of flexibility and mechanical strength, particularly a good balance of flexibility and tensile strength, can be easily obtained.
The contents of the structural units (i) and (ii) can be measured by ¹³ C-NMR, specifically by the method described in the examples below.

Examples of the α-olefin having 5 to 20 carbon atoms include 1-pentene, 3-methyl-1-butene, 1-hexene, 4-methyl-1-pentene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-nonadecene, and 1-eicosene. 1-hexene, 1-octene, and 1-dodecene are preferred, with 1-octene being more preferred, because they are capable of forming a crystalline structure with many tie molecules and resulting in a copolymer that is excellent in balance between flexibility and tensile strength.
Two or more of the α-olefins having 5 to 20 carbon atoms may be used, but preferably one type is used.

The copolymer (A) has a melting point Tm of 95° C. or lower as measured by DSC, or no melting point is observed as measured by DSC (no melting peak is observed by DSC).
When a melting point is observed, Tm is preferably 90° C. or lower, more preferably 85° C. or lower, with no particular lower limit.
When the melting point is within the above range, or when no melting point is observed, a composition (molded article) having excellent flexibility can be easily obtained.
The melting point is specifically measured by the method described in the Examples below. Here, the melting point refers to the temperature at the apex of a melting peak, and "no melting peak is observed" means that no crystalline melting peak with a heat of crystalline fusion (ΔH) of 1 J/g or more is observed in the range of -100 to 200°C. When two or more melting peaks are observed, the highest temperature among the apex temperatures of these peaks is the melting point.

When the melting peak is observed, the heat of fusion (ΔH), which is the integrated value of the peak, is preferably 1 to 50 J/g, more preferably 5 to 45 J/g, and even more preferably 10 to 40 J/g.
When ΔH is within the above range, a composition (molded article) having a good balance between flexibility and mechanical strength can be easily obtained.

The mm fraction of the copolymer (A) is 85% or more, preferably 90% or more, more preferably 92% or more, and particularly preferably 98% or more.
When the mm fraction is within the above range, a composition (molded article), particularly an injection molded article, having a good balance of excellent flowability, mechanical strength, and impact resistance can be easily obtained.
The mm fraction can be measured and analyzed by the method described in JP-A-2007-186664.

The intrinsic viscosity [η] of the copolymer (A) measured in decalin at 135° C. is 0.5 to 10 dl/g, preferably 1 to 5 dl/g, more preferably 1.5 to 2.5 dl/g.
When the intrinsic viscosity [η] is within the above range, a composition (molded article) excellent in properties such as moldability and mechanical strength can be easily obtained.

The MFR of the copolymer (A) measured in accordance with ASTM D1238E at 230° C. under a load of 2.16 kg is preferably 0.1 to 30 g/10 min, more preferably 0.2 to 15 g/10 min.
When the MFR is within the above range, a composition (molded article) having a good balance between moldability and mechanical strength can be easily obtained.

The tensile modulus of the copolymer (A) is preferably 0.5 to 200 MPa, more preferably 1 to 180 MPa, and even more preferably 2 to 150 MPa.
Specifically, the tensile modulus is measured by the method described in the examples below.

The breaking stress of the copolymer (A) is preferably 5 MPa or more, more preferably 10 MPa or more, and even more preferably 15 MPa or more.
Specifically, the breaking stress is measured by the method described in the examples below.

The Shore A hardness (instantaneous value) of the copolymer (A) is preferably 50 to 99, more preferably 60 to 98. When it is difficult to measure the Shore A hardness, the same evaluation can be performed using the Shore D hardness instead, and the Shore D hardness (instantaneous value) of the copolymer (A) is preferably 12 to 62, more preferably 18 to 60.
The Shore A hardness (instantaneous value) and the Shore D hardness (instantaneous value) are specifically measured by the method described in the examples below.
When the tensile modulus (and breaking stress) is within the above range and the Shore A hardness or Shore D hardness is within the above range, a composition (molded article) having a good balance between flexibility and mechanical strength such as tensile strength can be easily obtained.

The method for producing copolymer (A) is not particularly limited, but it can be produced by copolymerizing propylene and an α-olefin having 5 to 20 carbon atoms in the presence of a known catalyst, such as a catalyst primarily composed of a solid titanium component and an organometallic compound, or a metallocene catalyst using a metallocene compound as one of the catalyst components. Preferably, it is obtained by copolymerizing propylene and an α-olefin having 5 to 20 carbon atoms in the presence of a metallocene catalyst, and examples of such catalysts include those described in WO 2004/087775, JP 2007-186664, WO 2006/68308, WO 2014/50816, and WO 2014/50817.

The content of copolymer (A) is 1 to 99 mass%, preferably 5 to 95 mass%, more preferably 6 to 93 mass%, even more preferably 7 to 91 mass%, and particularly preferably 8 to 90 mass%, relative to 100 mass% of the total of copolymer (A) and polymer (B).
When the content of the copolymer (A) is within the above range, a composition (molded article) having a good balance of flexibility, tensile strength, and whitening resistance can be easily obtained.

<Propylene-Based Polymer (B)>
The propylene polymer (B) is not particularly limited as long as it is a polymer other than the copolymer (A) and has an MFR of 0.1 to 500 g/10 min at 230°C under a load of 2.16 kg, as measured in accordance with ASTM D1238E.
The polymer (B) used in the present composition may be one type or two or more types.

The polymer (B) may be a homopolypropylene or a copolymer of propylene and an α-olefin other than propylene having 2 to 20 carbon atoms, etc. The copolymer may be a random copolymer (random polypropylene) or a block copolymer.
The polymer (B) is preferably a homopolypropylene or a random copolymer of propylene and an α-olefin having 2 to 20 carbon atoms other than propylene.
The polymer (B) may be an unmodified polymer or a modified polymer, such as the same polymers as the modified polyolefins described below.

Considering that molded articles having excellent heat resistance can be easily obtained, homopolypropylene is preferred, and considering that molded articles having excellent whitening resistance and impact properties can be easily obtained, the random copolymer is preferred.
The random copolymer is preferably a copolymer of propylene and an α-olefin having 2 to 10 carbon atoms other than propylene, or a copolymer of propylene, ethylene and an α-olefin having 4 to 10 carbon atoms.

In the random copolymer, the content of structural units derived from propylene is typically 90 mol% or more, based on a total of 100 mol% of structural units derived from propylene and structural units derived from α-olefins having 2 to 20 carbon atoms other than propylene. The content of structural units derived from α-olefins having 2 to 20 carbon atoms other than propylene is typically 10 mol% or less, preferably 8 mol% or less, more preferably 7.5 mol% or less, and preferably 0.1 mol% or more, more preferably 0.2 mol% or more.

Examples of the α-olefins having 2 to 20 carbon atoms other than propylene include ethylene, 1-butene, 1-pentene, 3-methyl-1-butene, 1-hexene, 4-methyl-1-pentene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-nonadecene, and 1-eicosene.
Two or more of the α-olefins having 2 to 20 carbon atoms other than propylene may be used.

The MFR of the polymer (B) is 0.1 to 400 g/10 min, preferably 0.5 g/10 min or more, and preferably 300 g/10 min or less, more preferably 200 g/10 min or less, even more preferably 100 g/10 min or less, and particularly preferably 90 g/10 min or less.
When the MFR is within the above range, a composition having excellent moldability can be easily obtained, and a composition (molded article) having excellent dispersibility with the copolymer (A) and excellent mechanical strength such as tensile strength can be easily obtained.

The melting point of the polymer (B) measured by DSC is preferably from 110 to 170°C, more preferably from 120 to 170°C, and even more preferably from 125 to 168°C.
A melting point within the above range is preferable because it provides a good balance of moldability, heat resistance and transparency, and also provides good properties as a crystalline polypropylene.
The melting point is the melting point (the temperature at the top of the melting peak) observed using a DSC measurement device when the sample is held at 200°C for 10 minutes, cooled to -20°C at a temperature decrease rate of 10°C/min, held at -20°C for 1 minute, and then heated again to 200°C at a temperature increase rate of 10°C/min.
The heat of fusion (ΔH), which is the integrated value of the melting peak, is preferably 50 mJ/mg or more.

The isotactic pentad fraction (mmmm fraction) of the polymer (B) is preferably 90% or more, more preferably 92% or more, and even more preferably 95% or more.
When the mmmm fraction is within the above range, a composition (molded article) having a good balance between rigidity and transparency, and particularly excellent transparency, can be easily obtained.
The mmmm fraction is the proportion of isotactic chains in pentad units in a molecular chain measured using ^13C -NMR, as described in JP 2007-186664 A, in other words, the fraction of propylene monomer units at the center of a chain in which five consecutive propylene monomer units are meso-bonded, and can be measured by the method described in the publication.

Polymer (B) can be produced by various known methods using Ziegler-Natta catalysts or metallocene catalysts.

The content of polymer (B) is 1 to 99 mass%, preferably 5 to 95 mass%, more preferably 7 to 94 mass%, even more preferably 9 to 93 mass%, and particularly preferably 10 to 92 mass%, relative to 100 mass% of the total of copolymer (A) and polymer (B).
When the content of the polymer (B) is within the above range, a composition (molded article) having a good balance of flexibility, tensile strength, and whitening resistance can be easily obtained.

<Additives>
The present composition may optionally contain additives other than the copolymer (A) and polymer (B), specifically, additives such as polyolefins other than the copolymer (A) and polymer (B) or modified products thereof, weather resistance stabilizers, heat resistance stabilizers, antistatic agents, antislip agents, antiblocking agents, antifogging agents, nucleating agents (crystal nucleating agents), lubricants, pigments, dyes, plasticizers, antioxidants, hydrochloric acid absorbers, and antioxidants, as long as the object of the present invention is not impaired.
These additives may be used alone or in combination of two or more.

For example, a crystal nucleating agent may be used from the viewpoints of increasing the crystallization rate, shortening the molding cycle, increasing transparency, and adjusting rigidity.
The crystal nucleating agent is preferably a substance that has a nucleating effect on the propylene-based resin, and specific examples include metal salts of aromatic carboxylic acids, metal salts of aromatic phosphates, alditol derivatives, and metal salts of rosin.

The aromatic carboxylic acid metal salt is preferably aluminum p-t-butylbenzoate. The aromatic phosphate metal salt is preferably 2,2'-methylenebis(4,6-di-t-butylphenyl)sodium phosphate or 2,2'-methylenebis(4,6-di-t-butylphenyl)aluminum phosphate. The alditol derivative is preferably a hexitol derivative or a nonitol derivative, and among these, p-methyl-benzylidene sorbitol, p-ethyl-benzylidene sorbitol, and 7,8,9-trideoxy-3,5:4,6-bis-O-[(4-propylphenyl)methylene]-D-glycero-L-gulo-nonitol are preferably used.
When a crystal nucleating agent is used, the content of the crystal nucleating agent in the present composition is usually 0.01 to 2% by mass, preferably 0.05 to 1% by mass.

<Method for preparing the present composition>
The present composition can be prepared by mixing the components to be blended in the composition by various known methods, for example, by mixing them using a Henschel mixer, V-blender, ribbon blender, tumbler blender, kneader-ruder, etc., or by melt-kneading them using a single-screw extruder, twin-screw extruder, kneader, Banbury mixer, etc. Furthermore, granulation, pulverization, etc. may be carried out as necessary.
When mixing or kneading these components, the components to be blended may be added all at once or in stages.

≪Adhesive resin composition≫
The adhesive resin composition according to the present invention contains the present composition. The adhesive resin composition may consist of the present composition alone, or may contain the present composition together with other components.
The content of the present composition in the adhesive resin composition is preferably 1 to 50% by mass, more preferably 1 to 40% by mass.

It is preferable that the adhesive resin composition contains a modified polyolefin, since this has better adhesion and compatibility with the substrate (other resin), and may further improve the wettability of the surface of the resulting molded article.
Specific examples of the modified polyolefin include those obtained by graft-modifying the copolymer (A) or polymer (B) with one or more polar monomers.

Suitable examples of the polar monomer include unsaturated carboxylic acids and/or derivatives thereof, such as unsaturated compounds having one or more carboxylic acid groups, esters of unsaturated carboxylic acid compounds having a carboxylic acid group with alkyl alcohols, and unsaturated compounds having one or more carboxylic acid anhydride groups (e.g., acid anhydrides of unsaturated dicarboxylic acids).
Examples of the unsaturated moiety in these compounds include a vinyl group, a vinylene group, and an unsaturated cyclic hydrocarbon group.
The polar monomer is preferably an unsaturated dicarboxylic acid or an acid anhydride thereof, more preferably maleic acid, nadic acid or an acid anhydride thereof.

The modification amount (graft amount of polar monomer) in the modified polyolefin is usually 0.1% by mass or more, preferably 0.2% by mass or more, and usually 50% by mass or less, preferably 30% by mass or less, more preferably 10% by mass or less, relative to 100% by mass of the modified polyolefin, in order to obtain better adhesion and compatibility with the substrate (other resin).
The degree of modification can be controlled, for example, by appropriately selecting the grafting conditions.

The method for grafting the polar monomer is not particularly limited, and any conventionally known graft polymerization method, such as a solution method or melt-kneading method, can be used. Specifically, for example, the copolymer (A) or polymer (B) is melted or dissolved in a solvent to form a solution, to which the graft monomer is added to carry out the graft reaction.

When the modified polyolefin is blended into the adhesive resin composition, the content of the modified polyolefin is preferably 40 to 90% by mass, more preferably 40 to 80% by mass, relative to 100% by mass of the adhesive resin composition.
When the content of the modified polyolefin is within the above range, a composition exhibiting high adhesive strength can be easily obtained.

The adhesive resin composition is typically laminated to one or both sides of a single-layer or multi-layer substrate to form a multilayer film. Specifically, it is used as a multilayer film by co-extruding the adhesive resin composition and a substrate layer using a known multilayer film molding method such as a T-die film molding method or an inflation film molding method, or by providing the adhesive resin composition on a pre-formed substrate.

The substrate is not particularly limited, but is preferably a substrate made of a thermoplastic resin.
Examples of the thermoplastic resin include polypropylene-based resins (e.g., homopolypropylene, copolymers of propylene and a small amount of α-olefin), polyethylene-based resins (e.g., low-density polyethylene, medium-density polyethylene, high-density polyethylene, linear low-density polyethylene), known ethylene-based polymers (e.g., ethylene-α-olefin copolymer, ethylene-ethyl acrylate copolymer, ethylene-vinyl acetate copolymer, ethylene-methyl methacrylate copolymer, ethylene-n-butyl acrylate copolymer, ethylene-vinyl alcohol copolymer), poly-4-methyl-pentene-1, and mixtures thereof.
The substrate may be surface-treated by a conventionally known method, or may be colored or printed.

The multilayer film can be suitably used as a surface protection film to protect metal plates such as aluminum plates, steel plates, and stainless steel plates, as well as coated plates of these metal plates, glass plates, synthetic resin plates, and other processing components, as well as home appliances, automobile parts, and electronic components that use these components.Specific examples of suitable applications include films used in the electronics field, such as optical plate protective films, lens protective films, backgrinding tapes for semiconductor wafers, dicing tapes, and protective tapes for printed circuit boards, as well as window glass protective films and baked coating films.

The adhesive resin composition can be prepared by mixing the components to be blended in the composition by various known methods, for example, by mixing them with a Henschel mixer, V-blender, ribbon blender, tumbler blender, kneader-ruder, etc., or by melt-kneading them with a single-screw extruder, twin-screw extruder, kneader, Banbury mixer, etc. Furthermore, granulation, pulverization, etc. may be carried out as necessary.
When mixing or kneading these components, the components to be blended may be added all at once or in stages.

<Pellets>
The pellet according to the present invention contains the present composition or the adhesive resin composition.
The shape, size, etc. of the pellets are not particularly limited and may be appropriately selected depending on the desired application.
The pellets can be produced by melting the present composition or the adhesive resin composition in a kneader such as a Banbury mixer, a roll or an extruder, and granulating the melted composition.

<Molded body>
The molded article according to the present invention comprises the present composition or the adhesive resin composition.
The molded article can be produced by molding the present composition or the adhesive resin composition by a conventionally known molding method, for example, a sheet (film) molding method, a blow molding method, an injection molding method, a press molding method, an extrusion molding method, an inflation molding method, an extrusion blow molding method, an injection blow molding method, a vacuum molding method, a calendar molding method, or a melt T-die casting method.

The molded article is not particularly limited, but since the present composition and the adhesive resin composition exhibit the above-mentioned effects, it is preferable that the molded article is one in which the effects are more effectively exhibited.
Specific examples of the molded article include (unstretched) films, sheets, injection molded articles, blow molded articles, and automobile parts (e.g., automobile interior parts, automobile exterior parts). More specific examples include civil engineering and building material parts such as multi-layer hoses, pipes, tubes, decorative sheets, and flooring mats, coating materials for electric wires and cables (e.g., insulating layers, sheath layers), nonwoven fabrics, stretch films, food packaging films, packaging sheets, food packaging trays and beverage cups (thermoformed from the sheet), and plastic containers (folded from the sheet).

<Non-stretched film>
The non-stretched film is not particularly limited as long as it is a non-stretched film, and the shape, size (thickness), etc. may be appropriately selected depending on the desired application. The non-stretched film may be a single layer or a multilayer. If it is a multilayer film, at least one layer of the film may contain the present composition or the adhesive resin composition. When the non-stretched film is a multilayer film, all of the layers are not stretched.

The thickness of the unstretched film (total thickness if multi-layered) is preferably 5 to 150 μm, more preferably 10 to 100 μm.
In this specification, no particular distinction is made between film and sheet, but a film generally refers to a membranous body having a thickness of less than 250 μm, and a sheet generally refers to a thin plate-like body having a thickness of 250 μm or more.

Specific uses of the unstretched film include, for example, packaging films for packaging food, liquids, pharmaceuticals, etc.

<Sheet>
The sheet is not particularly limited, and its shape, size (thickness), etc. may be appropriately selected depending on the desired application. The sheet may be a single layer or a multilayer. In the case of a multilayer sheet, at least one layer of the sheet may contain the present composition or the adhesive resin composition.

The thickness of the sheet (total thickness if multi-layered) is preferably 250 to 2000 μm, more preferably 250 to 1500 μm.

Specific uses of the sheet include, for example, packaging sheets for packaging food, liquids, medicines, etc., and containers formed from the sheet (e.g., trays and cups thermoformed from the sheet, and containers formed by folding the sheet).

<Injection molded articles and blow molded articles>
The injection molded article is not particularly limited, but examples thereof include molded articles produced by injection molding into a desired shape using a conventionally known injection molding apparatus under known conditions.
The injection molded articles can be used in a wide range of applications, such as trim materials for automobile interiors, exterior parts for automobiles, housings for home appliances, containers, tubes, and pipes.

The blow molded article is not particularly limited, but examples thereof include molded articles produced by blow molding into a desired shape using a conventionally known blow molding apparatus under known conditions.
The blow molded article may be a multi-layered article, in which case at least one layer contains the present composition or the adhesive resin composition.

Specific uses for the injection-molded and blow-molded articles include, for example, food containers, beverage containers, caps, pharmaceutical containers, and various other containers; everyday items (e.g., clothing cases, buckets, washbasins, stationery such as writing implements, containers, toys, cooking utensils, and various other cases); housings for home appliances; automobile parts; tubes; and pipes.

<Automotive interior and exterior parts>
The automobile interior and exterior parts are not particularly limited, and examples thereof include automobile parts molded by injection molding or the like.
Specific examples of the automobile interior parts include trim, instrument panels, and column covers, while specific examples of the automobile exterior parts include fenders, bumpers, side moldings, mudguards, and mirror covers.

The present invention will be described below using examples, but the present invention is not limited to these examples.

[Production Example 1] Production of Propylene-α-Olefin Copolymer (A-1) A 950 mL continuous polymerization reactor, the atmosphere of which had been thoroughly purged with nitrogen, was supplied with dry hexane at a rate of 1,807 mL/hr through one supply port, and with 1-octene at a rate of 355 mL/hr and a hexane solution of triisobutylaluminum (4.5 mmol/L) at a rate of 57 mL/hr through another supply port. Simultaneously, propylene was supplied at a rate of 1,080 mL/hr and hydrogen at a rate of 0.19 NL/hr through another supply port of the continuous polymerization reactor. A propylene-α-olefin copolymer (8-octamethylfluoren-12'-yl-(2-(adamantan-1-yl)-8-methyl-3,3b,4,5,6,7,7a,8-octahydrocyclopenta[a]indene))zirconium diisobutylaluminum copolymer (A-1) synthesized according to Synthesis Example 4 of Japanese Patent No. 5,980,339 was added. A hexane solution (0.03 mmol/L, zirconium/methylaluminoxane = 1/300 molar ratio) prepared by contacting zirconium chloride (hereinafter also referred to as "catalyst a") with methylaluminoxane (manufactured by Tosoh Finechem Corporation) was supplied into the polymerization reactor at a rate of 60 mL/hr, and continuous solution polymerization was carried out under conditions of a polymerization temperature of 65 ° C, a total pressure of 3.6 MPaG, a residence time of 17 min, and a stirring speed of 700 rpm. Thereafter, a methanol/hexane solution (methanol/hexane = 2/98 volume ratio) was added at a rate of 100 mL/hr to terminate the polymerization. Next, the mixture was dried under a nitrogen atmosphere at 180 ° C for 30 minutes and then dried under vacuum for 30 minutes, thereby producing a propylene-α-olefin copolymer (A-1) at a production rate of 163 g/hr.

Production Example 2 Production of Propylene/α-Olefin Copolymer (A-2) Propylene/α-olefin copolymer (A-2) was produced in the same manner as in Production Example 1, except that the feed rate of dry hexane was changed to 1718 mL/hr, the feed rate of 1-octene to 440 mL/hr, the concentration and feed rate of the hexane solution of triisobutylaluminum to 4 mmol/L and 61 mL/hr, respectively, the feed rate of hydrogen to 0.15 NL/hr, and the feed rate of the hexane solution in which catalyst a had been contacted with methylaluminoxane to 52 mL/hr.

Production Example 3 Production of Propylene/α-Olefin Copolymer (A-3) Propylene/α-olefin copolymer (A-3) was produced in the same manner as in Production Example 1, except that the feed rate of dry hexane was changed to 1891 mL/hr, the feed rate of 1-octene to 265 mL/hr, the concentration and feed rate of the hexane solution of triisobutylaluminum to 4 mmol/L and 80 mL/hr, respectively, the feed rate of hydrogen to 0.1 NL/hr, and the feed rate of the hexane solution in which catalyst a had been contacted with methylaluminoxane to 69 mL/hr.

Production Example 4 Production of Propylene-α-Olefin Copolymer (A-4) Dry hexane was supplied to a 950 mL continuous polymerization reactor that had been thoroughly purged with nitrogen through one supply port at a rate of 1,852 mL/hr, and 1-octene was supplied to another supply port at a rate of 585 mL/hr. A hexane solution (0.05 mmol/L, zirconium/methylaluminoxane/triisobutylaluminum=1/250/200 molar ratio) of diphenylmethylene(3-tert-butyl-5-ethylcyclopentadienyl)(2,7-di-tert-butylfluorenyl)zirconium dichloride (hereinafter also referred to as "catalyst b") synthesized according to Synthesis Example 4 of WO 2006/025540, in contact with methylaluminoxane and triisobutylaluminum was supplied to the polymerization reactor at a rate of 82 mL/hr. Simultaneously, propylene was supplied at a rate of 1,340 mL/hr and hydrogen at a rate of 0.03 NL/hr from another supply port of the continuous polymerization reactor, and continuous solution polymerization was carried out under the conditions of a polymerization temperature of 65 ° C, a total pressure of 3.6 MPaG, a residence time of 15 min, and a stirring speed of 700 rpm. Thereafter, a methanol/hexane solution (methanol/hexane = 2/98 volume ratio) was added at a rate of 100 mL/hr to terminate the polymerization. Next, the mixture was dried for 30 minutes under a nitrogen atmosphere at 180 ° C and then dried for 30 minutes under vacuum, thereby producing a propylene-α-olefin copolymer (A-4) at a production rate of 146 g/hr.

Production Example 5 Production of Propylene/α-Olefin Copolymer (A-5) A propylene/α-olefin copolymer (A-5) was produced in the same manner as in Production Example 4, except that the feed rates of dry hexane were changed to 1737 mL/hr, 1-octene to 695 mL/hr, and the hexane solution in which catalyst b, methylaluminoxane, and triisobutylaluminum had been contacted was changed to 101 mL/hr.

Production Example 6 Production of Propylene/α-Olefin Copolymer (A-6) Propylene/α-olefin copolymer (A-6) was produced in the same manner as in Production Example 4, except that the feed rate of dry hexane was changed to 1552 mL/hr, the feed rate of 1-octene to 395 mL/hr, the feed rate of a hexane solution in which catalyst b, methylaluminoxane, and triisobutylaluminum had been brought into contact with each other to 72 mL/hr, the feed rate of propylene to 1300 mL/hr, the feed rate of hydrogen to 0.01 NL/hr, the polymerization temperature to 74°C, and the residence time to 17 min.

Production Example 7 Production of Propylene/α-Olefin Copolymer (A-7) Dry hexane was supplied to a 950 mL continuous polymerization vessel that had been thoroughly purged with nitrogen through one supply port at a rate of 1,506 mL/hr, and 1-octene was supplied to another supply port at a rate of 560 mL/hr and a hexane solution of triisobutylaluminum (7.5 mmol/L) was supplied to the other supply port at a rate of 60 mL/hr. Simultaneously, through another supply port of the continuous polymerization reactor, propylene was supplied at a rate of 1180 mL/hr, hydrogen at a rate of 0.04 NL/hr, and a hexane solution (0.05 mmol/L, zirconium/methylaluminoxane = 1/300 molar ratio) prepared by contacting methylaluminoxane with a metallocene catalyst represented by the following formula (hereinafter also referred to as "Catalyst c") synthesized according to Synthesis Example 2 of Japanese Patent No. 6,568,082 was supplied at a rate of 55 mL/hr, and continuous solution polymerization was carried out under the conditions of a polymerization temperature of 65°C, a total pressure of 3.6 MPaG, a residence time of 17 min, and a stirring speed of 700 rpm. Thereafter, a methanol/hexane solution (methanol/hexane = 2/98 volume ratio) was added at a rate of 100 mL/hr to terminate the polymerization. The mixture was then dried in a nitrogen atmosphere at 180° C. for 30 minutes and then dried in vacuum for 30 minutes to produce a propylene/α-olefin copolymer (A-7) at a production rate of 219 g/hr.

[Comparative propylene-α-olefin copolymer]
As comparative propylene/α-olefin copolymers, the following propylene/α-olefin copolymers (cA-1) and (cA-2) were used.
Propylene/α-olefin copolymer (cA-1): Propylene/ethylene copolymer manufactured by ExxonMobil Chemical Corporation (trade name: Vistamaxx 3980, MFR (230°C, 2.16 kg load) = 8 g/10 min)
Propylene/α-olefin copolymer (cA-2): A propylene/ethylene copolymer manufactured by ExxonMobil Chemical Corporation (trade name: Vistamaxx 3000, MFR (230°C, 2.16 kg load) = 7 g/10 min) was used.

<Physical Properties of Copolymers (A-1) to (A-7) and (cA-1) to (cA-2)>
The physical properties of the copolymers (A-1) to (A-7) and (cA-1) to (cA-2) obtained in the above Production Examples were measured by the following methods. The results are shown in Table 1.

a) Propylene and α-olefin contents The propylene and α-olefin contents in the copolymer were calculated by analyzing ^the obtained ^C -NMR spectrum after C-NMR measurement under the following conditions. In this specification, the content of structural units derived from α-olefins is also referred to as the "α-olefin content."
Apparatus: AVANCE III cryo-500 nuclear magnetic resonance apparatus manufactured by Bruker Biospin Measurement nucleus: ¹³ C (125 MHz)
Measurement mode: Single pulse proton broadband decoupling Pulse width: 45° (5.00 μsec)
Number of points: 64k
Measurement range: 250 ppm (-55 to 195 ppm)
Repeat time: 5.5 seconds Number of times of accumulation: 64 Measurement solvent: orthodichlorobenzene/benzene-d ₆ (4/1 [v/v])
Sample concentration: ca. 60 mg/0.6 mL
Measurement temperature: 120℃
Window function: exponential (BF: 1.0 Hz)
Chemical shift reference: CH ₃ (P) mmmm signal (21.59 ppm)

b) Isotactic triad fraction (mm fraction)
C-NMR measurement was performed on an orthodichlorobenzene/benzene- _d (4/1 [v/v]) solution ( _CH (P) mmmm signal: ^21.59 ppm as reference), and the ratio (%) of the area of the peak appearing between 21.0 and 22.2 ppm to the total area (100%) of the peaks appearing between 19.2 and 22.2 ppm in the obtained ^C -NMR spectrum was calculated, and the ratio (%) of the area of this peak was taken as the mm fraction.

c) MFR
The MFR of the copolymer was measured at 230° C. under a load of 2.16 kg in accordance with ASTM D1238E.

d) Intrinsic viscosity [η]
The intrinsic viscosity [η] of the copolymer was measured at 135° C. using decalin as a solvent.

e) Melting point Tm, heat of fusion ΔH
Using a hydraulic hot press molding machine set at 200°C, the copolymer was heated for 6 minutes, molded under a pressure of 10 MPa for 2 minutes, and then cooled at 20°C under a pressure of 10 MPa for 2 minutes to produce a sheet (test piece) with a thickness of 500 μm.
After 72 hours at room temperature from molding, a test piece weighing approximately 10 mg was cooled in a nitrogen atmosphere from 20°C to -20°C at a rate of 10°C/min and held at that temperature for 5 minutes. The test piece was then heated to 200°C at a rate of 10°C/min, held at that temperature for 10 minutes, cooled to -100°C at a rate of 10°C/min, held at that temperature for 5 minutes, and then heated to 200°C at a rate of 10°C/min.
The heat of fusion ΔH was calculated from the integrated value of the crystalline melting peak when the temperature was raised for the first time. The melting point Tm was the temperature at the peak apex of the crystalline melting peak when the temperature was raised for the second time. When two or more melting peaks were observed, the highest temperature among the peak apex temperatures of these peaks was taken as the melting point.

f) Tensile modulus and breaking stress Using a hydraulic hot press molding machine set at 200°C, the copolymer was heated for 6 minutes, molded under a pressure of 10 MPa for 2 minutes, and then cooled at 20°C under a pressure of 10 MPa for 2 minutes to produce a sheet with a thickness of 2 mm.
After 72 hours at room temperature from molding, 5A type dumbbells as specified in JIS K 7161-2:2014 were prepared from the obtained sheet in accordance with ASTM D638, and the tensile modulus and breaking stress of the dumbbells were measured under conditions of 23°C and a pulling rate of 50 mm/min.

g) Shore A hardness (instantaneous value)
Using a hydraulic hot press molding machine set at 200°C, the copolymer was heated for 6 minutes, molded under a pressure of 10 MPa for 2 minutes, and then cooled at 20°C under a pressure of 10 MPa for 2 minutes to produce a sheet with a thickness of 2 mm.
After 72 hours at room temperature from molding, a durometer hardness tester (Type A) was used, and the indenter was brought into contact with a test piece consisting of three stacked sheets, and the scale was immediately read (in accordance with ASTM D2240).

h) Shore D hardness (instantaneous value)
Using a hydraulic hot press molding machine set at 200°C, the copolymer was heated for 6 minutes, molded under a pressure of 10 MPa for 2 minutes, and then cooled at 20°C under a pressure of 10 MPa for 2 minutes to produce a sheet with a thickness of 2 mm.
After 72 hours at room temperature from molding, a durometer (D type) was used, and the indenter was brought into contact with a test piece consisting of three stacked sheets, and the scale was immediately read (in accordance with ASTM D2240).

[Examples 1 to 7 and Comparative Examples 1 and 2]
The raw materials shown in the compositions in Table 2 were placed in a Laboplastomill (manufactured by Toyo Seiki Seisakusho, Ltd.) in the amounts (mass%) shown in Table 2, and kneaded for 5 minutes under conditions of 200°C and 60 rpm to prepare a propylene-based resin composition.
The propylene polymers (B-1) used in the examples and comparative examples are as follows:
Propylene polymer (B-1): Random polypropylene (Prime Polymer Co., Ltd., Prime Polypro F227, MFR (230°C, 2.16 kg load) = 7 g/10 min, melting point = 150°C, mmmm fraction = 96%)

The tensile modulus, breaking stress, and Shore D hardness (instantaneous value) were measured in the same manner as above, except that the resulting propylene-based resin composition was used. The results are shown in Table 2.

<Whitening resistance>
The obtained propylene-based resin composition was heated for 6 minutes using a hydraulic hot press molding machine set at 200°C, then molded for 2 minutes under a pressure of 10 MPa, and then cooled at 20°C under a pressure of 10 MPa for 2 minutes to produce a sheet with a thickness of 500 μm.
After 72 hours had passed at room temperature from molding, a No. 2 dumbbell shape as specified in JIS K 6251 was made from the obtained sheet, and this was stretched 15 mm at a tensile speed of 50 mm/min. The hue (L value) before and after stretching was measured using a spectrophotometer (CM-3700d, manufactured by Konica Minolta, Inc.), and the change in hue (ΔL) was calculated based on the following formula. A smaller ΔL value indicates better whitening resistance.
ΔL = L value (after stretching) - L value (before stretching)

Claims (11)

1 to 99% by mass of a propylene/α-olefin copolymer (A) satisfying the following requirements (I) to (V):
A propylene-based resin composition comprising 1 to 99% by mass of a propylene-based polymer (B) other than the copolymer (A), the propylene-based polymer (B) having an MFR of 0.1 to 500 g/10 min at 230°C under a load of 2.16 kg, as measured in accordance with ASTM D1238E (where the total of the copolymer (A) and the polymer (B) is taken as 100% by mass).
(I) When the total of the structural unit (i) derived from propylene and the structural unit (ii) derived from an α-olefin having 5 to 20 carbon atoms is taken as 100 mol%, the content of the structural unit (i) is more than 85 mol% but not more than 95 mol%, and the content of the structural unit (ii) is 5 mol% or more but less than 15 mol%. (II) The melting point measured by differential scanning calorimetry (DSC) is 95°C or less, or is not observed. (III) The isotactic triad fraction measured by ^13C -NMR is 85% or more. (IV) The intrinsic viscosity [η] measured in decalin at 135°C is 0.5 to 10 dl/g. (V) The α-olefin having 5 to 20 carbon atoms is at least one selected from 1-hexene, 1-octene, 1-decene, and 1-dodecene. 2. The propylene-based resin composition according to claim 1, wherein the copolymer (A) has an isotactic triad fraction of 90% or more as measured by ¹³ C-NMR. The propylene-based resin composition according to claim 1 or 2, wherein the copolymer (A) has an MFR of 0.1 to 30 g/10 min at 230°C under a load of 2.16 kg, as measured in accordance with ASTM D1238E. An adhesive resin composition comprising the propylene-based resin composition according to any one of claims 1 to 3. Pellets containing the propylene-based resin composition according to any one of claims 1 to 3 or the adhesive resin composition according to claim 4. A molded article comprising the propylene-based resin composition according to any one of claims 1 to 3 or the adhesive resin composition according to claim 4. An unstretched film comprising the propylene-based resin composition according to any one of claims 1 to 3 or the adhesive resin composition according to claim 4. A sheet comprising the propylene-based resin composition according to any one of claims 1 to 3, or the adhesive resin composition according to claim 4. An injection-molded article comprising the propylene-based resin composition according to any one of claims 1 to 3 or the adhesive resin composition according to claim 4. A blow-molded article comprising the propylene-based resin composition according to any one of claims 1 to 3 or the adhesive resin composition according to claim 4. An automobile part selected from interior and exterior parts, comprising the propylene-based resin composition according to any one of claims 1 to 3 or the adhesive resin composition according to claim 4.