Inorganic filler-containing polypropylene resin composition

Abstract

To provide a polypropylene resin composition which is excellent in balance between rigidity and surface impact resistance and which contains an inorganic filler-containing propylene-based polymer composition, a polyamide resin, and a modified elastomer.SOLUTION: A polypropylene resin composition contains a propylene-based polymer composition (a) and a polyolefin composition (b). The propylene-based polymer composition (a) contains a specific propylene-based polymer (a1) and a filler (a2). The polyolefin composition (b) contains a polyolefin (b1), an aliphatic polyamide resin (b2), a modified elastomer (b3) and an acid-modified polypropylene (b4). The polypropylene resin composition has a specific phase structure. The modified elastomer (b3) is an elastomer in which a part including a group reactive to the aliphatic polyamide resin (b2) is added to a specific unmodified elastomer (b3').SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to an inorganic filler-containing propylene-based polymer composition and a polypropylene resin composition containing a polyamide resin.

Background Art

[0002] Resin compositions containing a propylene-based polymer, a polyamide resin, and a modified elastomer having an acid group such as an acid anhydride group serving as a compatibilizer have been studied as resins with improved impact resistance, and it has been clarified that a specific phase structure is formed (see, for example, Patent Documents 1 to 4). In addition, for the purpose of improving impact resistance and rigidity, resin compositions containing a propylene-based polymer, a polyamide resin containing a filler (for example, an inorganic filler, natural fiber, etc.), and a modified elastomer having a group reactive with the polyamide resin have been studied.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0004] For the purpose of further improving the physical properties (e.g., impact resistance on the surface) of a resin composition containing a propylene-based polymer, a polyamide resin, and a modified elastomer, it is conceivable to consider a propylene-based polymer composition containing an inorganic filler, a polyamide resin, and a resin composition containing a modified elastomer, with the inorganic filler incorporated into the propylene-based polymer. However, according to the studies by the present inventors, it has been found that even a resin composition simply containing a filler-added propylene-based polymer, a polyamide resin, and a modified elastomer will result in a significant reduction in rigidity, and it has become clear that further improvement is required for practical use.

[0005] An object of the present invention is to provide a polypropylene resin composition containing a propylene-based polymer composition containing an inorganic filler, a polyamide resin, and a modified elastomer, which is excellent in the balance between rigidity and impact resistance on the surface.

[0006] As a result of investigations conducted by the present inventors under such circumstances, in addition to a propylene-based polymer composition containing an inorganic filler, a polyolefin composition containing a polyolefin, an aliphatic polyamide resin, a modified elastomer, and acid-modified propylene, it has been found that a propylene-based polymer composition having a specific phase structure can solve the above problems, leading to the completion of the present invention.

Means for Solving the Problems

[0007] The present invention includes the following [1] to [7]. [1] A polypropylene resin composition containing a propylene-based polymer composition (a) and a polyolefin composition (b), The propylene-based polymer composition (a) contains a propylene-based polymer (a1) and an inorganic filler (a2), and the amount of the decane-soluble part of the propylene-based polymer (a1) at room temperature (23 °C) is 22 to 35% by mass based on the total mass of the propylene-based polymer (a1), The polyolefin composition (b) contains a polyolefin (b1), an aliphatic polyamide resin (b2), a modified elastomer (b3), and acid-modified polypropylene (b4). The polypropylene resin composition has a continuous phase (α') containing a propylene-based polymer (a1), a polyolefin (b1), and an acid-modified polypropylene (b4), an inorganic filler (a2) dispersed in the continuous phase (α'), and a dispersed phase (β) containing an aliphatic polyamide resin (b2) and a modified elastomer (b3). The dispersed phase (β) is composed of a melt-kneaded product of the aliphatic polyamide resin (b2) and the modified elastomer (b3). The modified elastomer (b3) is an elastomer obtained by adding a portion containing a group reactive with the aliphatic polyamide resin (b2) to an unmodified elastomer (b3'), and the unmodified elastomer (b3') is an olefinic thermoplastic elastomer containing a structural unit derived from ethylene and a structural unit derived from an α-olefin having 3 to 8 carbon atoms, or a styrenic thermoplastic elastomer containing a structural unit derived from a styrenic compound. A polypropylene resin composition characterized in that when the total of the continuous phase (α') and the dispersed phase (β) is 100% by mass, the dispersed phase (β) is 80% by mass or less. [2] The polypropylene resin composition according to [1], wherein the propylene-based polymer (a1) is a propylene-ethylene block copolymer having a dispersed phase of an ethylene polymer block. [3] The polypropylene resin composition according to [1] or [2], wherein the inorganic filler (a2) is at least one inorganic filler selected from the group consisting of talc, mica, glass fiber, and calcium carbonate. [4] The polypropylene resin composition according to any one of [1] to [3], wherein the polyolefin (b1) is a propylene homopolymer. [5] The polypropylene resin composition according to any one of [1] to [4], wherein the aliphatic polyamide resin (b2) is at least one aliphatic polyamide resin selected from the group consisting of polyamide 6, polyamide 11, polyamide 12, polyamide 612, polyamide 610, and polyamide 1010. [6] The dispersed phase (β) has a continuous phase (β1) containing the aliphatic polyamide resin (b2) and a finely dispersed phase (β2) containing a modified elastomer (b3) dispersed in the continuous phase (β1). The polypropylene resin composition according to any one of [1] to [5]. [7] The content of the propylene-based polymer composition (a) is 50 to 94.9 parts by mass, and the content of the polyolefin composition (b) is 5 to 49.9 parts by mass (however, the total content of the propylene-based polymer composition (a) and the polyolefin composition (b) is 100 parts by mass). The polypropylene resin composition according to any one of [1] to [6].

Effect of the Invention

[0008] According to the present invention, it is possible to provide a propylene-based polymer composition containing an inorganic filler, a polyamide resin, and a polypropylene resin composition containing a modified elastomer, which are excellent in the balance between rigidity and impact resistance.

Mode for Carrying Out the Invention

[0009] Hereinafter, the present invention will be described. ≪Polypropylene Resin Composition≫ The polypropylene resin composition according to the present invention contains a propylene-based polymer composition (a) and a polyolefin composition (b).

[0010] <Propylene-Based Polymer Composition (a)> The propylene-based polymer composition (a) used in the present invention contains a propylene-based polymer (a1) and an inorganic filler (a2).

[0011] [Propylene-Based Polymer (a1)] The propylene-based polymer (a1) is not particularly limited as long as it is a polymer containing a structural unit derived from propylene as a main component (typically containing more than 50 mol% of the structural unit derived from propylene), and it may be a propylene homopolymer or a copolymer of propylene and an α-olefin other than propylene (hereinafter also referred to as "other α-olefin") (hereinafter also referred to as "propylene-α-olefin copolymer"). The propylene-α-olefin copolymer may be a propylene-α-olefin block copolymer or a propylene-α-olefin random copolymer.

[0012] Examples of the above other α-olefins include ethylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicosene, 4-methyl-1-pentene, 2-methyl-1-butene, 3-methyl-1-butene, 3-methyl-1-butene, 3,3-dimethyl-1-butene, 3-methyl-1-pentene, 3-methyl-1-hexene, 3,5,5-trimethyl-1-hexene, etc., and α-olefins having 4 to 20 carbon atoms such as ethylene. Among these, as the other α-olefin, ethylene and 1-butene are preferable, and ethylene is more preferable.

[0013] Preferable specific examples of the propylene-α-olefin copolymer include propylene-ethylene copolymer and propylene-1-butene copolymer, and a propylene-ethylene copolymer is preferable.

[0014] From the viewpoint of excellent balance between the rigidity and the impact resistance of the obtained polypropylene resin composition, the propylene-based polymer (a1) is preferably a propylene-ethylene block copolymer having a dispersed phase of an ethylene polymer block. As the monomer that is a raw material of the propylene-based polymer (a1), for example, a monomer derived from fossil fuel may be used, a monomer derived from biomass may be used, or a monomer derived from fossil fuel and a monomer derived from biomass may be used. These monomers may be used alone or in combination of two or more.

[0015] The amount of the decane-soluble part of the propylene-based polymer (a1) at room temperature (23°C) is 22% by mass to 35% by mass based on the total mass of the propylene-based polymer (a1). The above-mentioned decane-soluble part at room temperature (23°C) refers to the component soluble in n-decane at 23°C (hereinafter also referred to as "decane-soluble part") when the propylene-based polymer (a1) is fractionated with an n-decane solvent. The amount of the decane-soluble part is measured by the following method.

[0016] (Ratio of n-decane-soluble component at 23°C) Approximately 3 g of the propylene-based polymer, 500 ml of n-decane, and a small amount of a heat-resistant stabilizer soluble in n-decane were charged into a glass measuring container, and the temperature was raised to 150°C in 2 hours while stirring with a stirrer under a nitrogen atmosphere to dissolve the propylene-based polymer. After holding at 150°C for 2 hours, it was gradually cooled to 23°C over 8 hours. The liquid containing the precipitate of the obtained propylene-based polymer was filtered under reduced pressure using a glass filter of the 25G-4 standard manufactured by Iwata Glass Co., Ltd. 100 ml of the filtrate was collected and dried under reduced pressure to obtain a part of the n-decane-soluble component. After this operation, the ratio (mass%) of the n-decane-soluble component at 23°C was determined by the following formula. The mass of the propylene-based polymer was measured up to the unit of 10 -4 g, and this mass was represented as b (g) in the following formula. Also, the mass of a part of the decane-soluble component was measured up to the unit of 10 -4 g, and this mass was represented as a (g) in the following formula. Ratio of n-decane-soluble component at 23°C (mass%) = 100×(500×a) / (100×b)

[0017] The amount of the decane-soluble part is preferably 22 to 35% by mass, more preferably 24 to 32% by mass, and still more preferably 25 to 30% by mass, based on the total mass of the propylene-based polymer (a1). When the content of the decane-soluble part is within the above range, the molded article (for example, an automotive interior material or an automotive exterior material) formed from the composition is excellent in mechanical properties such as rigidity and impact resistance.

[0018] The decane-soluble part mainly consists of a propylene-α-olefin copolymer such as a propylene-ethylene random copolymer when the propylene-based polymer (a1) is a copolymer, and may contain a part of the propylene homopolymer, for example, by-products generated during polymerization such as low molecular weight substances. When the propylene-based polymer (a1) is a copolymer of propylene and another α-olefin, the other α-olefin contained in the decane-soluble part, and the α-olefin of the propylene-α-olefin copolymer in the decane-soluble part, include ethylene and / or an α-olefin having 4 to 12 carbon atoms. Specific examples of such other α-olefins include ethylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 3-methyl-1-pentene, 1-heptene, 1-octene, 1-nonene, 1-decene, and 1-dodecene. Among these, ethylene is preferred as the other α-olefin.

[0019] The component other than the decane-soluble part of the propylene-based polymer (a1), that is, the decane-insoluble part, usually consists only of structural units derived from propylene. However, when the propylene-based polymer (a1) is a copolymer of propylene and another α-olefin, it may contain structural units derived from other monomers other than propylene in a small amount, for example, 10 mol% or less, preferably 5 mol% or less. Examples of the other monomers other than propylene include α-olefins other than propylene such as ethylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 3-methyl-1-pentene, 1-heptene, 1-octene, 1-nonene, 1-decene, and 1-dodecene. Among these, ethylene and α-olefins having 4 to 10 carbon atoms are preferred. These may be copolymerized alone or two or more of them may be copolymerized.

[0020] The intrinsic viscosity ([η]) measured in decalin at 135°C of the decane-soluble part of the propylene-based polymer (a1) is preferably 0.1 to 10.0 dl / g, more preferably 1.0 to 9.8 dl / g, still more preferably 1.5 to 9.5 dl / g, and particularly preferably 2.0 to 9.0 dl / g.

[0021] When the intrinsic viscosity ([η]) of the decane-soluble part is within the above range, the automotive interior materials and automotive exterior materials formed from the composition are excellent in the balance between rigidity and impact resistance. When further mechanical properties are required for the automotive interior materials and automotive exterior materials formed from the composition, the intrinsic viscosity ([η]) of the above decane-soluble part is preferably 4.0 to 9.0 dl / g, more preferably 4.5 to 8.7 dl / g, and still more preferably 5.0 to 8.4 dl / g.

[0022] The MFR (ASTM D1238, 230°C, 2.16 kg load) of the propylene-based polymer (a1) is preferably 1 to 200 g / 10 min, more preferably 10 to 100 g / 10 min, and still more preferably 20 to 50 g / 10 min. When the propylene-based polymer (a1) having an MFR within the above range is used, the balance between the fluidity and impact resistance of the obtained polypropylene resin composition is more excellent.

[0023] [Inorganic filler (a2)] The inorganic filler (a2) is not particularly limited, and known fillers can be used as long as the effects of the present invention are not impaired. Examples of the inorganic filler (a2) include carbon black, or carbon black surface-treated with graphite or a silane coupling agent; fine powder silica, silica (including fumed silica, precipitated silica, diatomaceous earth, and quartz), alumina, iron oxide, ferrite, magnesium oxide, titanium oxide, antimony trioxide, zirconium oxide, barium oxide, calcium oxide, and other oxide-based fillers; aluminum hydroxide, magnesium hydroxide, and other hydroxide-based fillers; aluminum silicate (clay), magnesium silicate (talc), mica, kaolin, calcium silicate, glass fiber, glass flake, glass bead, and other silicate-based fillers; diatomaceous earth, limestone, and other sedimentary rock-based fillers; montmorillonite (montmorillonite), magnesian montmorillonite, tetramontmorillonite, tetramagnesium montmorillonite, beidellite, aluminian beidellite, nontronite, aluminian nontronite, saponite (saponite), aluminian saponite, hectorite, sauconite, stevensite, bentonite, and other clay mineral-based fillers; ferrite, iron, cobalt, and other magnetic-based fillers; silver, gold, copper, and their alloys, and other conductive fillers; aluminum nitride, boron nitride, silicon carbide, and other heat-conductive fillers; aluminum sulfate, magnesium sulfate, barium sulfate, calcium sulfate, and other sulfate-based fillers; calcium sulfite, and other sulfite-based fillers; calcium carbonate, basic magnesium carbonate, dolomite, and other carbonate-based fillers; barium titanate, potassium titanate, and other titanate-based fillers; and the like.

[0024] From the viewpoint of excellent balance between the rigidity and the impact resistance of the obtained polypropylene resin composition, as the inorganic filler (a2), talc, mica, glass fiber, and calcium carbonate are preferable, and talc is more preferable.

[0025] These inorganic fillers (a2) may be used alone or in combination of two or more thereof.

[0026] From the viewpoint of better dispersibility in the propylene-based polymer composition (a), the particle size of the inorganic filler (a2) is preferably 0.01 μm to 100 μm, more preferably 0.1 μm to 80 μm, still more preferably 1 μm to 50 μm. The particle size (average particle size) of the inorganic filler is the 50% particle size (d50) obtained from the cumulative % distribution curve measured by a laser diffraction particle size distribution measuring device.

[0027] The mass ratio of the propylene-based polymer (a1) contained in the propylene-based polymer composition (a) to the inorganic filler (a2) (mass of the propylene-based polymer (a1) / mass of the inorganic filler (a2), hereinafter also simply referred to as "(a1) / (a2)") is preferably 65 / 35 to 99 / 1. In other words, in the propylene-based polymer composition (a) of the present invention, when the total of the propylene-based polymer (a1) and the inorganic filler (a2) is 100 parts by mass, the content of the propylene-based polymer (a1) is 65 to 99 parts by mass, and the content of the inorganic filler (a2) is 1 to 35 parts by mass.

[0028] From the viewpoint of more suitably achieving the effects of the present invention, the content of the propylene-based polymer (a1) in the propylene-based polymer composition (a) is preferably 70 parts by mass or more, more preferably 75 parts by mass or more, still more preferably 80 parts by mass or more, and is preferably 97 parts by mass or less, more preferably 95 parts by mass or less, still more preferably 93 parts by mass or less. In particular, when the content of the propylene-based polymer (a1) in the propylene-based polymer composition (a) is within the above range, the resulting polypropylene resin composition is more likely to have improved rigidity and is less likely to cause a significant decrease in impact resistance.

[0029] The content of the inorganic filler (a2) in the propylene-based polymer composition (a) is preferably 3 parts by mass or more, more preferably 5 parts by mass or more, even more preferably 7 parts by mass or more, and is preferably 30 parts by mass or less, more preferably 25 parts by mass or less, even more preferably 20 parts by mass or less. Here, when two or more propylene-based polymers (a1) are used, the total amount of the propylene-based polymers (a1) is the above-mentioned "content of the propylene-based polymer (a1)". Further, when two or more inorganic fillers (a2) are used, the total amount of the inorganic fillers (a2) is the above-mentioned "content of the inorganic filler (a2)".

[0030] In addition to the propylene-based polymer (a1) and the inorganic filler (a2), the propylene-based polymer composition (a) may contain additives such as a heat stabilizer, an antistatic agent, a weather stabilizer, a light stabilizer, an anti-aging agent, an antioxidant, a fatty acid metal salt, a softening agent, a dispersant, a filler, a colorant, a lubricant, and a pigment, as long as the effects of the present invention are not impaired.

[0031] The propylene-based polymer composition (a) can be produced by mixing the above-described components by a conventionally known method. For example, the propylene-based polymer (a1), the inorganic filler (a2), and the additives contained as necessary are mixed with a Henschel mixer, a V-blender, a ribbon blender, a tumbler blender, or the like, and the obtained mixture is melt-kneaded with an extruder to produce a pelletized propylene-based polymer composition (a).

[0032] <Polyolefin composition (b)> The polyolefin composition (b) used in the present invention contains a polyolefin (b1), an aliphatic polyamide resin (b2), a modified elastomer (b3), and an acid-modified polypropylene (b4).

[0033] [Polyolefin (b1)] The polyolefin (b1) is a homopolymer of α-olefins (including ethylene) such as ethylene, propylene, 1-butene, 4-methyl-1-pentene, a copolymer of the above α-olefins and other α-olefins, and a copolymer of the above α-olefins and monomers other than α-olefins, and is a polymer mainly composed of α-olefins. Specific examples of the above polyolefin (b1) include the following ethylene-based polymers, propylene-based polymers, and 1-butene-based polymers.

[0034] 〈Ethylene-based polymer〉 The above ethylene-based polymer is a homopolymer of ethylene or a copolymer of ethylene and an α-olefin having 3 to 20 carbon atoms. Usually, high-density polyethylene (HDPE), medium-density polyethylene (MDPE), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and polymers mainly composed of structural units derived from ethylene, which are called ethylene·α-olefin copolymers (typically containing more than 50 mol% of structural units derived from ethylene) can be mentioned. Specific examples of the α-olefin having 3 to 20 carbon atoms copolymerized with ethylene include propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicosene, 2-methyl-1-butene, 3-methyl-1-butene, 3,3-dimethyl-1-butene, 3-methyl-1-pentene, 3-methyl-1-hexene, etc., α-olefins having 4 to 20 carbon atoms. Among them, α-olefins having 3 to 10 carbon atoms are preferred, α-olefins having 3 to 8 carbon atoms are more preferred, and particularly ethylene, 1-butene, 1-hexene, 4-methyl-1-pentene, and 1-octene are even more preferred. The molar ratio of ethylene to α-olefin (ethylene / α-olefin) is preferably 99 / 1 to 60 / 40, more preferably 95 / 5 to 70 / 30, and even more preferably 90 / 10 to 60 / 25.

[0035] Preferable specific examples of the above ethylene·α-olefin copolymer include ethylene·propylene copolymer, ethylene·1-butene copolymer, ethylene·1-hexene copolymer, ethylene·4-methyl-1-pentene copolymer, ethylene·1-octene copolymer, and ethylene·propylene·1-butene copolymer.

[0036] 〈Propylene-based polymer〉 The above propylene-based polymer is a polymer having structural units derived from propylene as the main component (typically containing more than 50 mol% of structural units derived from propylene), such as a homopolymer of propylene (homo-PP), a copolymer of propylene with ethylene and / or an α-olefin having 4 to 20 carbon atoms (random copolymer: random-PP), and a composition of a homopolymer of propylene and an ethylene·propylene copolymer (block copolymer: block-PP). Specific examples of the α-olefin in the propylene·α-olefin copolymer include ethylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicosene, 2-methyl-1-butene, 3-methyl-1-butene, 3,3-dimethyl-1-butene, 3-methyl-1-pentene, 3-methyl-1-hexene, etc., i.e., ethylene and α-olefins having 4 to 20 carbon atoms. Among them, ethylene and α-olefins having 4 to 10 carbon atoms are preferred, ethylene and α-olefins having 4 to 8 carbon atoms are more preferred, and particularly ethylene, 1-butene, 1-hexene, 4-methyl-1-pentene, and 1-octene are even more preferred. The molar ratio of propylene to α-olefin (propylene / α-olefin) is preferably 99 / 1 to 60 / 40, more preferably 95 / 5 to 70 / 30, and even more preferably 90 / 10 to 60 / 25.

[0037] Preferable specific examples of the above propylene-α-olefin copolymer (random PP) include propylene-ethylene copolymer, propylene-1-butene copolymer, propylene-1-hexene copolymer, propylene-4-methyl-1-pentene copolymer, propylene-1-octene copolymer, and propylene-ethylene-1-butene copolymer. Among them, propylene-ethylene copolymer is particularly preferable.

[0038] When the above propylene polymer is a propylene-ethylene block copolymer (block PP), the amount of the decane-soluble part of the propylene-ethylene block copolymer at room temperature (23°C) is preferably 8% by mass or more and 35% by mass or less, more preferably 8% by mass or more and 28% by mass or less. Also, the intrinsic viscosity [η] measured in decalin at 135°C for the decane-soluble part at room temperature (23°C) is preferably 1.0 dl / g or more and 10.0 dl / g or less. Further, the ethylene amount (content of structural units derived from ethylene) of the decane-soluble part at room temperature (23°C) is preferably 33 mol% or more and 48 mol% or less, more preferably 37 mol% or more and 43 mol% or less.

[0039] When the above propylene polymer is a propylene homopolymer, the preferable melting point is 155 to 170°C, more preferably 158 to 165°C. When the above propylene polymer is a propylene-ethylene random copolymer, the ethylene amount of the propylene-ethylene random copolymer is preferably 1.9 to 5.4% by mass, more preferably 2.0 to 4.8% by mass. Also, the crystal melting point measured by a differential scanning calorimeter (DSC) according to JIS K7121 for the propylene-ethylene random copolymer is preferably usually 130 to 150°C, more preferably 130 to 145°C, and particularly preferably 135 to 145°C.

[0040] The propylene-ethylene block copolymer and the propylene-ethylene random copolymer may be used alone or in combination of two or more copolymers. For example, two or more copolymers can also be mixed for MFR adjustment.

[0041] <1-Butene Polymer> The above 1-butene polymer is a polymer mainly composed of structural units derived from 1-butene, such as a homopolymer of 1-butene (polybutene) and a copolymer of 1-butene with ethylene, propylene, and α-olefins having 5 to 20 carbon atoms (1-butene·α-olefin copolymer) (typically containing more than 50 mol% of structural units derived from 1-butene).

[0042] Among these polyolefins (b1), from the viewpoint of excellent balance between the rigidity and the impact resistance of the resulting polypropylene resin composition, a propylene polymer is preferable, and a propylene homopolymer is more preferable. The polyolefin (b1) may be used alone or a mixture of two or more copolymers may be used.

[0043] The MFR (ASTM D1238, 230 °C, 2.16 kg load) of the polyolefin (b1) is preferably 1 to 200 g / 10 min, more preferably 5 to 100 g / 10 min, and still more preferably 10 to 70 g / 10 min. When the polyolefin (b1) having an MFR within the above range is used, it becomes easy to form the phase structure of the polyolefin composition (b) described later, and the balance between the rigidity and the impact resistance of the resulting polypropylene resin composition can be made more excellent. As the monomer that is the raw material of the polyolefin (b1), for example, a monomer derived from fossil fuel may be used, a monomer derived from biomass may be used, or a monomer derived from fossil fuel and a monomer derived from biomass may be used. These monomers may be used alone or two or more of them may be used.

[0044] [Aliphatic Polyamide Resin (b2)] The aliphatic polyamide resin (b2) is not particularly limited, and various conventionally known aliphatic polyamide resins can be used without limitation as long as the effects of the present invention are not impaired. For example, an amino acid lactam or a melt-moldable aliphatic polyamide resin obtained by polycondensation reaction of a diamine and a dicarboxylic acid can be used. Specific examples of the aliphatic polyamide resin (b2) include the following resins.

[0045] (1) Polycondensates of organic dicarboxylic acids having 4 to 12 carbon atoms and organic diamines having 2 to 13 carbon atoms, such as polyhexamethylene adipamide [polyamide 66], which is a polycondensate of hexamethylenediamine and adipic acid, polyhexamethylene azelamide [polyamide 69], which is a polycondensate of hexamethylenediamine and azelaic acid, polyhexamethylene sebacamide [polyamide 610], which is a polycondensate of hexamethylenediamine and sebacic acid, polyhexamethylene dodecanoamide [polyamide 612], which is a polycondensate of hexamethylenediamine and dodecanedioic acid, and a polycondensate [polyamide 1010] of a diamine having 10 carbon atoms (1,10-decanediamine (decamethylenediamine) made from castor oil) and a dicarboxylic acid having 10 carbon atoms (sebacic acid). Examples of the organic dicarboxylic acid include adipic acid, pimelic acid, suberic acid, sebacic acid, dodecanedioic acid, etc. Examples of the organic diamine include hexamethylenediamine, octamethylenediamine, nonanediamine, octanediamine, decanediamine, undecanediamine, dodecanediamine, etc. (2) Polycondensates of ω-amino acids, such as polyundecanamide [polyamide 11], which is a polycondensate of ω-aminoundecanoic acid. (3) Ring-opening polymers of lactams, such as polycapramide [polyamide 6], which is a ring-opening polymer of ε-aminocapro-lactam, and poly lauric lactam [polyamide 12], which is a ring-opening polymer of ε-aminolauryl lactam.

[0046] Among the aliphatic polyamide resins (b2), polyamide 6, polyamide 11, polyamide 12, polyamide 612, polyamide 610, and polyamide 1010 are preferred from the viewpoint of excellent balance between the rigidity and the impact resistance of the resulting polypropylene resin composition.

[0047] The aliphatic polyamide resin (b2) may be used alone or in combination of two or more. As the raw material of the aliphatic polyamide resin (b2), either a raw material derived from fossil fuel or a raw material derived from biomass can be used. Further, a raw material derived from fossil fuel and a raw material derived from biomass may be used in combination.

[0048] The melt volume rate (MVR) of the aliphatic polyamide resin (b2) measured at 275 °C under a load of 2.16 kg is preferably 50 to 300 cm 3 / 10 min, more preferably 100 to 250 cm 3 / 10 min, particularly preferably 125 to 200 cm 3 / 10 min. By using such an aliphatic polyamide resin, the impact resistance inherent to the polyamide resin tends to be sufficiently exhibited, and the impact resistance is not significantly impaired even when it is used in mixture with the modified elastomer (b3).

[0049] [Modified elastomer (b3)] The modified elastomer (b3) is an elastomer obtained by adding a portion containing a group having reactivity with the aliphatic polyamide resin (b2) to an unmodified elastomer (b3').

[0050] The unmodified elastomer (b3') serving as the raw material of the modified elastomer (b3) is an olefinic thermoplastic elastomer (b3'-1) containing a structural unit derived from ethylene and a structural unit derived from an α-olefin having 3 to 8 carbon atoms, or a styrenic thermoplastic elastomer (b3'-2) containing a structural unit derived from a styrenic compound.

[0051] The olefinic thermoplastic elastomer (b3'-1) is an elastomer containing structural units derived from ethylene and structural units derived from α-olefins having 3 to 8 carbon atoms, preferably containing 75 to 95 mol%, more preferably 75 to 90 mol% of the structural units derived from ethylene, and preferably 5 to 25 mol%, more preferably 10 to 25 mol% of the structural units derived from α-olefins having 3 to 8 carbon atoms. Examples of the α-olefins having 3 to 8 carbon atoms include propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, and 1-octene. Among these α-olefins having 3 to 8 carbon atoms, 1-butene, 1-hexene, and 1-octene are preferred. The α-olefins having 3 to 8 carbon atoms may be used alone or in combination of two or more. Ethylene and α-olefins having 3 to 8 carbon atoms, which are monomers constituting the olefinic thermoplastic elastomer (b3'-1), may be, for example, monomers derived from fossil fuels and / or monomers derived from biomass, and these monomers may be used alone or in combination of two or more.

[0052] The content of the structural units derived from α-olefins having 3 to 8 carbon atoms in the olefinic thermoplastic elastomer (b3'-1) is preferably 5 to 25 mol%, more preferably 10 to 25 mol%, still more preferably 11 to 22 mol%, and particularly preferably 12 to 20 mol%. When the content of the structural units derived from α-olefins having 3 to 8 carbon atoms is within the above range, a modified elastomer with good flexibility and easy handling can be obtained. In addition, a polypropylene resin composition excellent in impact resistance can be obtained.

[0053] The melt flow rate (MFR) of the olefinic thermoplastic elastomer (b3’-1) measured at 230°C under a load of 2.16 kg is preferably 0.1 to 30 g / 10 min, more preferably 0.3 to 20 g / 10 min, and even more preferably 0.5 to 10 (g / 10 min). When the melt flow rate is within the above range, the compatibility between the modified elastomer (b3) obtained by adding a reactive group to the olefinic thermoplastic elastomer (b3’-1) and the aliphatic polyamide resin (b2) becomes good, and a polypropylene resin composition excellent in impact resistance can be obtained.

[0054] The olefinic thermoplastic elastomer (b3’-1) can be prepared, for example, by randomly copolymerizing ethylene and an α-olefin having 3 to 8 carbon atoms in the presence of a vanadium-based catalyst composed of a soluble vanadium compound and an alkylaluminum halide compound, or a zirconium-based catalyst composed of a metallocene compound of zirconium and an organoaluminum oxy compound.

[0055] Examples of the styrenic thermoplastic elastomer (b3’-2) include block copolymers of styrenic compounds and conjugated diene compounds, and hydrogenated products thereof.

[0056] Examples of the above styrenic compounds include alkylstyrenes such as styrene, α-methylstyrene, p-methylstyrene, p-t-butylstyrene, etc., p-methoxystyrene, and vinylnaphthalene. These styrenic compounds may be used alone or in combination of two or more. Examples of the above conjugated diene compounds include butadiene, isoprene, piperylene, methylpentadiene, phenylbutadiene, 3,4-dimethyl-1,3-hexadiene, and 4,5-diethyl-1,3-octadiene. These conjugated diene compounds may be used alone or in combination of two or more.

[0057] Specific examples of the styrenic thermoplastic elastomer (b3'-2) include styrene-butadiene-styrene copolymer (SBS), styrene-isoprene-styrene copolymer (SIS), styrene-ethylene / butylene-styrene copolymer (SEBS), styrene-ethylene / propylene-styrene copolymer (SEPS), and the like. Among these styrenic thermoplastic elastomers (b3'-2), SEBS is preferred. These styrenic thermoplastic elastomers (b3'-2) may be used alone or in combination of two or more.

[0058] Examples of the group having reactivity with the aliphatic polyamide resin (b2) (a group having reactivity with the aliphatic polyamide resin (b2) that will be included in the modified elastomer (b3), hereinafter simply referred to as "reactive group") include an acid anhydride group (-CO-O-OC-), a carboxyl group (-COOH), an epoxy group {-C-O-C- (a three-membered ring structure composed of two carbon atoms and one oxygen atom)}, an oxazoline group (-C3H4NO), and an isocyanate group (-NCO). In the modified elastomer (b3), only one kind of these reactive groups may be contained, or two or more kinds may be contained.

[0059] The graft modification amount (content of the portion derived from the monomer containing the reactive group) in the modified elastomer (b3) is not particularly limited as long as the effects of the present invention are achieved. However, it is preferably 0.1 to 5% by mass, more preferably 0.5 to 2% by mass, and still more preferably 0.8 to 1.4% by mass per mass of the modified elastomer (b3).

[0060] The method for adding the portion containing the reactive group to the unmodified elastomer (b3') is not particularly limited. For example, a method of adding a reactive group by performing a chemical reaction on a specific group contained in the unmodified elastomer (b3') (for example, when a carbon-carbon double bond exists in the unmodified elastomer (b3'), introducing an epoxy group by oxidizing this carbon-carbon double bond), a method of graft-modifying and adding a monomer containing a reactive group to the unmodified elastomer (b3'), and the like can be mentioned.

[0061] Examples of the monomer containing a reactive group used for graft modification include a monomer having a polymerizable unsaturated bond and an acid anhydride group, a monomer having a polymerizable unsaturated bond and a carboxyl group, a monomer having a polymerizable unsaturated bond and an epoxy group, and the like. Specifically, acid anhydrides such as maleic anhydride, itaconic anhydride, succinic anhydride, glutaric anhydride, adipic anhydride, citraconic anhydride, tetrahydrophthalic anhydride, butenyl succinic anhydride; carboxylic acids such as maleic acid, itaconic acid, fumaric acid, acrylic acid, methacrylic acid, etc. can be mentioned. Among these monomers containing reactive groups, acid anhydrides are preferred, maleic anhydride and itaconic anhydride are more preferred, and maleic anhydride is even more preferred. These monomers containing reactive groups may be used alone or in combination of two or more. The monomer containing a reactive group used for graft modification (for example, maleic acid or its anhydride) may be a monomer derived from fossil fuel, may be a monomer derived from biomass, or may be used in combination of a monomer derived from fossil fuel and a monomer derived from biomass.

[0062] When producing the modified elastomer (b3) by adding a monomer containing a reactive group by graft-modifying the unmodified elastomer (b3’), the graft modification amount of the modified elastomer (b3) is preferably 0.1 to 5% by mass, more preferably 0.5 to 2% by mass, and even more preferably 0.8 to 1.4% by mass. If the modification amount is too small, the surface impact resistance of the obtained polypropylene resin composition may decrease. If the modification amount is too large, foreign substances such as gels may be mixed into the modified elastomer (b3).

[0063] When producing the modified elastomer (b3) by graft modification, for example, it can be produced by graft-modifying the above-mentioned carboxylic acid (for example, maleic acid) or acid anhydride (for example, maleic anhydride) to the unmodified elastomer (b3’) in the presence of a radical initiator.

[0064] The charged amount of the carboxylic acid or acid anhydride is usually 0.010 to 15 parts by mass, preferably 0.010 to 5.0 parts by mass, based on 100 parts by mass of the unmodified elastomer (b3’). The usage amount of the radical initiator is usually 0.0010 to 1.0 parts by mass, preferably 0.0010 to 0.30 parts by mass, based on 100 parts by mass of the unmodified elastomer (b3’).

[0065] As the radical initiator, for example, organic peroxides, azo compounds, metal hydrides, etc. can be used. The radical initiator can be used by mixing it directly with the carboxylic acid or acid anhydride, and the unmodified elastomer (b3’), etc., but it may also be used after dissolving it in a small amount of organic solvent. As this organic solvent, an organic solvent capable of dissolving the radical initiator can be used.

[0066] The graft modification with the carboxylic acid or acid anhydride can be carried out by a conventionally known method. For example, the unmodified elastomer (b3’) is dissolved in an organic solvent, and then the carboxylic acid or acid anhydride, the radical initiator, etc. are added to the solution, and reacted at a temperature of 70 to 200 °C, preferably 80 to 190 °C, for 0.5 to 15 hours, preferably 1 to 10 hours, whereby the modified elastomer (b3) can be produced by graft modification.

[0067] Also, using an extruder, etc., the modified elastomer (b3) can be produced by reacting the carboxylic acid or acid anhydride and the unmodified elastomer (b3’) in the absence of a solvent in the presence of a radical initiator. This reaction is desirably carried out at a temperature equal to or higher than the temperature at which the unmodified elastomer (b3’) becomes molten for 0.5 to 10 minutes.

[0068] As the modified elastomer (b3), the melt flow rate (MFR) measured at 230 °C under a load of 2.16 kg is 0.1 to 50 (g / 10 min), preferably 0.5 to 10 (g / 10 min). By controlling the MFR within this range, the resulting polypropylene resin composition has excellent resistance to surface impact.

[0069] [Acid-modified polypropylene (b4)] Acid-modified polypropylene (b4) is an acid-modified product of unmodified polypropylene. Acid-modified polypropylene (b4) can be obtained by acid-modifying unmodified polypropylene with a compound selected from unsaturated carboxylic acids and their derivatives, and preferably can be obtained by modifying unmodified polypropylene with maleic acid or its anhydride. Acid-modified polypropylene (b4) may be prepared using unmodified polypropylene alone or in combination of two or more. As the monomer that is the raw material of acid-modified polypropylene (b4), for example, a monomer derived from fossil fuel may be used, a monomer derived from biomass may be used, or a monomer derived from fossil fuel and a monomer derived from biomass may be used. These monomers may be used alone or in combination of two or more.

[0070] Acid-modified polypropylene (b4) can be produced, for example, by graft-modifying unmodified polypropylene with a compound selected from unsaturated carboxylic acids and their derivatives. When producing acid-modified polypropylene (b4) by graft modification, for example, it can be produced by graft-modifying unmodified polypropylene with an unsaturated carboxylic acid (such as maleic acid) or an unsaturated carboxylic acid derivative (such as an acid anhydride such as maleic anhydride) in the presence of a radical initiator. The conditions for graft modification are the same as those for producing modified elastomer (b3) by graft modification. As radical initiators that can be used in the production of acid-modified polypropylene (b4) by graft modification, 1,1-di(t-butylperoxy)cyclohexane, 2,2-di(4,4-di-(t-butylperoxy)cyclohexyl)propane, t-hexylperoxyisopropyl monocarbonate, t-butylperoxymaleic acid, t-butylperoxy-3,5,5-trimethylhexanoate, t-butylperoxylaurate, t-butylperoxyisopropyl monocarbonate, t-butylperoxy-2-ethylhexyl monocarbonate, t-hexylperoxybenzoate, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, t-butylperoxyacetate, 2,2-di(t-butylperoxy)butane, t-butylperoxybenzoate, n-butyl-4,4-di(t-butylperoxy)valerate, di(2-t-butylperoxyisopropyl)benzene, dicumyl peroxide, di-t-hexyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, t-butylcumyl peroxide, di-t-butyl peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane can be mentioned. Among these, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane is preferable.

[0071] The acid-modified polypropylene (b4) preferably satisfies at least one of the following requirements (b4-i) and (b4-ii), and more preferably satisfies both of the following requirements (b4-i) and (b4-ii).

[0072] Requirement (b4-i) The melt flow rate (MFR) of the acid-modified polypropylene (b4) at 190 °C under a load of 2.16 kg is in the range of 100 to 300 g / 10 min. The melt flow rate of the acid-modified polypropylene (b4) can be measured under the conditions of 190 °C and a load of 2.16 kg in accordance with ASTM D1238. The melt flow rate of the acid-modified polypropylene (b4) is preferably in the range of 120 to 280 g / 10 min, more preferably in the range of 140 to 260 g / 10 min, and even more preferably in the range of 160 to 240 g / 10 min. When the melt flow rate of the acid-modified polypropylene (b4) is within the above range, the strength of the resulting polypropylene resin composition tends to be more excellent.

[0073] Requirement (b4-ii) The density is in the range of 0.895 to 0.920 kg / cm 3 . The density of the acid-modified polypropylene (b4) can be measured in accordance with ASTM D1505. The density of the acid-modified polyolefin (b4) is preferably 0.896 to 0.915 kg / cm 3 , more preferably 0.897 to 0.910 kg / cm 3 . When the density of the acid-modified polyolefin (b4) is within the above range, the handleability of the pellets of the acid-modified polyolefin (b4) is excellent, and the decrease in the rigidity of the resulting polypropylene resin composition can be more suppressed.

[0074] In the polyolefin composition (b), it has a continuous phase (α) containing the polyolefin (b1) and a dispersed phase (β) containing the aliphatic polyamide resin (b2) and the modified elastomer (b3) dispersed in the continuous phase (α), and it is desirable that the dispersed phase (β) consists of a melt kneaded product of the aliphatic polyamide resin (b2) and the modified elastomer (b3). For the polyolefin composition (b) having such a phase structure, when it is contained in the polypropylene resin composition, a polypropylene resin composition having a more excellent balance between rigidity and resistance to surface impact is easily obtained.

[0075] The dispersed phase (β) preferably has a continuous phase (β1) containing the aliphatic polyamide resin (b2) and a finely dispersed phase (β2) containing a modified elastomer (b3) dispersed in the continuous phase (β1). When the dispersed phase (β) has such a phase structure, a polypropylene resin composition excellent in surface impact resistance is easily obtained.

[0076] In the polyolefin composition (b), when a propylene-ethylene block copolymer having a dispersed phase of an ethylene block is used as the propylene-based polymer (a1) contained in the propylene-based polymer composition (a), at least a part of the ethylene block tends to aggregate at the interface between the continuous phase (α) and the dispersed phase (β). By having such a phase structure, the surface impact resistance of the obtained polypropylene resin composition tends to be more excellent.

[0077] The size of the dispersed phase (β) in the continuous phase (α) of the polyolefin composition (b) is not particularly limited as long as the effects of the present invention are achieved, and is the same as the preferred embodiment of the size (average diameter) of the dispersed phase (β) contained in the continuous phase (α') of the polypropylene resin composition described later. The method for obtaining the average diameter (average particle diameter) of the dispersed phase (β) is the same as the method for obtaining the average diameter of the dispersed phase (β) contained in the continuous phase (α') of the polypropylene resin composition described later.

[0078] When the dispersed phase (β) of the polyolefin composition (b) has the above continuous phase (β1) and the finely dispersed phase (β2) dispersed in the continuous phase (β1), the size of the finely dispersed phase (β2) is not particularly limited as long as the effects of the present invention are achieved, and is the same as the preferred embodiment of the size (average diameter) of the finely dispersed phase (β2) when the finely dispersed phase (β2) is contained in the dispersed phase (β) of the polypropylene resin composition described later. The method for obtaining the average diameter (average particle diameter) of the dispersed phase (β) is the same as the method for obtaining the average diameter of the dispersed phase (β) contained in the continuous phase (α') of the polypropylene resin composition described later.

[0079] In the polyolefin composition (b), when the total of the continuous phase (α) and the dispersed phase (β) is 100% by mass, the dispersed phase (β) is preferably 80% by mass or less. That is, usually, when the polyolefin (b1) is Wb1 and the total amount of the aliphatic polyamide resin (b2) and the modified elastomer (b3) is Wb2 + b3, when the total of Wb1 and Wb2 + b3 is 100% by mass, the ratio of Wb2 + b3 is preferably 80% by mass or less (usually 0.5% by mass or more). By setting the ratio within the above-described range, it is possible to make the obtained polypropylene resin composition excellent in all of surface impact resistance, rigidity, and moldability. From this viewpoint, the above ratio is preferably 5% by mass or more and 78% by mass or less, more preferably 10% by mass or more and 77% by mass or less, further preferably 23% by mass or more and 76% by mass or less, even more preferably 30% by mass or more and 75% by mass or less, particularly preferably 33% by mass or more and 72% by mass or less, more particularly preferably 35% by mass or more and 67% by mass or less, and especially preferably 37% by mass or more and 63% by mass or less.

[0080] When the total of the aliphatic polyamide resin (b2) and the modified elastomer (b3) is 100% by mass, the content ratio of the aliphatic polyamide resin (b2) is preferably 10% by mass or more and 80% by mass or less. By setting the content ratio of the aliphatic polyamide resin (b2) within this range, it is easy to form a phase structure in which the polyolefin (b1) is the continuous phase (α) and the phase containing the aliphatic polyamide resin (b2) is the dispersed phase (β). As a result, it is easy to obtain a polypropylene resin composition having excellent impact resistance and excellent rigidity. From this viewpoint, the content ratio of the aliphatic polyamide resin (b2) is preferably 12% by mass or more and 78% by mass or less, more preferably 14% by mass or more and 75% by mass or less, still more preferably 25% by mass or more and 73% by mass or less, even more preferably 30% by mass or more and 71% by mass or less, particularly preferably 34% by mass or more and 68% by mass or less, and most preferably 40% by mass or more and 64% by mass or less. By setting the content ratio of the aliphatic polyamide resin (b2) within the above range, the dispersed phase (β) obtained from the aliphatic polyamide resin (b2) and the modified elastomer (b3) can be dispersed more finely. Furthermore, the amount of the aliphatic polyamide resin (b2) having a large specific gravity can be reduced, and the specific gravity of the polypropylene resin composition can be decreased. As a result, it is easy to obtain a polypropylene resin composition that is lightweight and has excellent impact resistance and rigidity.

[0081] The above polyolefin composition (b) used in the present invention can be produced, for example, as follows. First, the aliphatic polyamide resin (b2) and the modified elastomer (b3) are melt-kneaded so as to have, for example, the above-described content ratios to prepare a melt-kneaded product thereof. The obtained melt-kneaded product of the aliphatic polyamide resin (b2) and the modified elastomer (b3), the polyolefin (b1), and the acid-modified polypropylene (b4) are melt-kneaded so as to have, for example, the above-described content ratios to prepare the polyolefin composition (b). The melt-kneading method is not particularly limited. For example, there is a method of melt-kneading each component using a kneading device such as an extruder (single-screw extruder, twin-screw extruder, etc.), a kneader, and a mixer (high-speed flow mixer, paddle mixer, ribbon mixer, etc.). These devices may be used alone or in combination of two or more. Further, when producing the polyolefin composition (b) by melt-kneading, after producing a melt-kneaded product by melt-kneading the aliphatic polyamide resin (b2) and the modified elastomer (b3), continuously, this melt-kneaded product, the polyolefin (b1), and the acid-modified polypropylene (b4) may be kneaded to produce the polyolefin composition (b). Alternatively, after producing a melt-kneaded product by melt-kneading the aliphatic polyamide resin (b2) and the modified elastomer (b3), for example, once producing pellets of this melt-kneaded product, the pellets of this melt-kneaded product may be melt-kneaded with the polyolefin (b1) and the acid-modified polypropylene (b4) to produce the polyolefin composition (b). Further, when melt-kneading, each component may be charged all at once and melt-kneaded, or each component may be charged and melt-kneaded in multiple portions. The temperature of melt-kneading can be appropriately set according to the type of resin used, etc., but it is desirable to knead in a state where each component is melted, and it is usually 190 to 350 °C, preferably 200 to 330 °C, more preferably 205 to 310 °C.

[0082] In addition to the propylene-based polymer composition (a) and the polyolefin composition (b), the polypropylene resin composition of the present invention may contain other polymers (for example, a copolymer composed only of ethylene and an α-olefin having 3 to 20 carbon atoms) within a range not impairing the effects of the present invention. The other polymers may be used alone or in combination of two or more. Further, the polypropylene resin composition of the present invention may contain additives within a range not impairing the effects of the present invention. Examples of the additives include a flame retardant, a flame retardant aid, a filler, a colorant, an antibacterial agent, an antistatic agent, etc. The additives may be used alone or in combination of two or more.

[0083] [Phase Structure of Polypropylene Resin Composition] In the polypropylene resin composition of the present invention, the propylene-based polymer (a1) contained in the propylene-based polymer composition (a), the polyolefin (b1) contained in the polyolefin composition (b), and the acid-modified polypropylene (b4) are integrated to form a continuous phase (α') containing the propylene-based polymer (a1), the polyolefin (b1), and the acid-modified polypropylene (b4). And the inorganic filler (a2) and the dispersed phase (β) formed of the polyolefin composition (b) are dispersed in this continuous phase (α'). Further, it is desirable that the dispersed phase (β) is dispersed in this continuous phase (α') in a state where the continuous phase (β1) and the finely dispersed phase (β2) phase dispersed in the continuous phase (β1) are formed in the dispersed phase (β). Such a desirable phase structure is presumed to be derived from the fact that in the polyolefin composition (b), the dispersed phase (β) has a continuous phase (β1) containing an aliphatic polyamide resin (b2) and a finely dispersed phase (β2) phase containing a modified elastomer (b3) dispersed in the continuous phase (β1). By having such a multi-dispersed phase structure, a polypropylene resin composition having more excellent impact resistance against surface is obtained.

[0084] Also, when a propylene-ethylene block copolymer having a dispersed phase of an ethylene polymer block is used as the propylene-based polymer (a1), at least a part of the ethylene polymer block contained in the block copolymer can be aggregated at the interface between the continuous phase (α') and the dispersed phase (β). By having such a phase structure, a polypropylene resin composition having more excellent impact resistance against surface is obtained.

[0085] The size of the dispersed phase (β) contained in the continuous phase (α') of the polypropylene resin composition is not particularly limited as long as the effects of the present invention are achieved. Usually, the average diameter (average particle diameter) is preferably 10,000 nm or less, more preferably 50 nm or more and 8,000 nm or less, and still more preferably 100 nm or more and 4,000 nm or less. The average diameter of this dispersed phase (β) is the average value (nm) of the maximum lengths of 50 randomly selected dispersed phases (β) in the image obtained during electron microscope observation. In addition, when the finely dispersed phase (β2) is formed in the dispersed phase (β) of the polypropylene resin composition of the present invention, its size is not particularly limited as long as the effects of the present invention are achieved. However, the average diameter (average particle diameter) is preferably 5 nm or more and 1,000 nm or less, more preferably 5 nm or more and 600 nm or less, still more preferably 10 nm or more and 400 nm or less, and particularly preferably 15 nm or more and 350 nm or less. The average diameter of this finely dispersed phase (β2) is the average value (nm) of the maximum lengths of 100 randomly selected finely dispersed phases (β2) in the image obtained using an electron microscope. In the polypropylene resin composition of the present invention, the acid-modified polypropylene (b4) is considered to be localized around the inorganic filler (a2). On the other hand, in a polypropylene resin composition not containing the acid-modified polypropylene (b4), the dispersed phase (β) in the polyolefin composition (b) tends to be localized around the inorganic filler (a2). Due to such differences in the phase structure, etc., a polypropylene resin composition having better rigidity can be obtained with the polypropylene resin composition of the present invention compared to a polypropylene resin composition not containing the acid-modified polypropylene (b4).

[0086] In the polypropylene resin composition of the present invention, when the total of the continuous phase (α') and the dispersed phase (β) is 100% by mass, the dispersed phase (β) is 80% by mass or less. Therefore, usually, the total amount of the propylene-based polymer (a1) and the polyolefin (b1) is W a1+b1 and the total amount of the aliphatic polyamide resin (b2) and the modified elastomer (b3) is W b2+b3 when, W a1+b1 and W b2+b3 the total of and is 100% by mass, Wb2+b3 The proportion is 80% by mass or less (usually 0.5% by mass or more). By setting the range of the above-described quantitative ratio, it is possible to make all of the impact resistance, rigidity, and moldability of the obtained polypropylene resin composition more excellent. From this viewpoint, the above proportion is preferably 1% by mass or more and 78% by mass or less, more preferably 3% by mass or more and 77% by mass or less, still more preferably 5% by mass or more and 76% by mass or less, even more preferably 8% by mass or more and 75% by mass or less, particularly preferably 10% by mass or more and 72% by mass or less, more particularly preferably 15% by mass or more and 67% by mass or less, and especially preferably 25% by mass or more and 63% by mass or less.

[0087] In the polypropylene resin composition of the present invention, the content ratio of each of the propylene-based polymer (a1) and the polyolefin (b1) is not particularly limited as long as the effects of the present invention are exhibited. However, when the total of the propylene-based polymer (a1) and the polyolefin (b1) is 100% by mass, the content ratio of the polyolefin (b1) is usually 80% by mass or less, preferably 1% by mass or more and 60% by mass or less, more preferably 3% by mass or more and 50% by mass or less, still more preferably 5% by mass or more and 40% by mass or less, and even more preferably 10% by mass or more and 35% by mass or less.

[0088] The specific gravity of the polypropylene resin composition of the present invention is not particularly limited, but is usually 1.05 or less, preferably 0.89 or more and 1.05 or less, and more preferably 0.92 or more and 0.98 or less. The polypropylene resin composition of the present invention has such a specific gravity, but also has impact resistance and rigidity superior to those of these resins even when compared with polyethylene resin alone or polypropylene resin alone.

[0089] In the polypropylene resin composition of the present invention, when the total content of the propylene-based polymer composition (a) and the polyolefin composition (b) is 100 parts by mass, the content of the propylene-based polymer composition (a) is preferably 50 to 95 parts by mass, and the content of the polyolefin composition (b) is preferably 5 to 50 parts by mass. More preferably, the content of the propylene-based polymer composition (a) is 55 to 90 parts by mass, and the content of the polyolefin composition (b) is 10 to 45 parts by mass. Even more preferably, the content of the propylene-based polymer composition (a) is 60 to 80 parts by mass, and the content of the polyolefin composition (b) is 20 to 40 parts by mass. With such a blending ratio, when each component is included, the balance between the rigidity and the impact resistance of the resulting polypropylene resin composition tends to be more excellent.

[0090] The polypropylene resin composition of the present invention can be produced, for example, as follows. For example, the propylene-based polymer composition (a) and the polyolefin composition (b) are prepared by the method described above or the like. Then, it can be produced by melt-kneading the propylene-based polymer composition (a), the polyolefin composition (b), and other components (for example, other polymers, additives) added as necessary. Further, it may be produced by adding a propylene-based polymer (a1) and an inorganic filler (a2) in place of the propylene-based polymer composition (a), that is, by melt-kneading the propylene-based polymer (a1), the inorganic filler (a2), the polyolefin composition (b), and other components added as necessary. The melt-kneading method is not particularly limited. For example, there is a method of melt-kneading each component using a kneading device such as an extruder (single-screw extruder, twin-screw extruder, etc.), a kneader, and a mixer (high-speed flow mixer, paddle mixer, ribbon mixer, etc.). These devices may be used alone or in combination of two or more. Also, when melt-kneading, each component may be charged all at once and melt-kneaded, or each component may be charged in multiple portions and melt-kneaded. The temperature for melt-kneading can be appropriately set according to the type of resin used, etc., but it is desirable to knead in a state where each component is melted, usually 190 to 350 °C, preferably 200 to 330 °C, more preferably 205 to 310 °C.

[0091] The polypropylene resin composition of the present invention can be made into a molded article by various thermoforming methods. The molded article thus obtained usually has a phase structure formed of the above-described polypropylene resin composition. Therefore, the obtained molded article is excellent in the balance between rigidity and impact resistance against the surface. Examples of the above-described thermoforming methods include injection molding, extrusion molding, blow molding, injection blow molding, inflation molding, hollow molding, vacuum molding, compression molding, press molding, stamping mold molding, transfer molding, and the like. The molded article may be manufactured by only one kind of molding method, or may be manufactured by combining two or more kinds of molding methods.

[0092] The polypropylene resin composition of the present invention can be used for various applications. For example, the polypropylene resin composition of the present invention is used as various articles used for vehicles such as automobiles, railway vehicles (entire vehicles), aircraft bodies (entire bodies), ships and hulls (entire hulls), bicycles (entire bodies), etc. Examples of automobile articles include exterior parts, interior parts, engine parts, electrical parts, and the like.

Examples

[0093] Hereinafter, the present invention will be described more specifically based on examples, but the present invention is not limited to these examples.

[0094] <Propylene-based polymer composition (a)> Propylene-based polymer composition (a-1): Talc-containing propylene-ethylene block copolymer (hereinafter, the propylene-ethylene block copolymer is also referred to as "block PP"). (Manufactured by Prime Polymer Co., Ltd., properties of block PP: melting temperature: 178 °C, amount of decane-soluble part (amount of n-decane-soluble component at 23 °C): 28% by mass, MFR: 30 g / 10 min; talc content in the propylene-based polymer composition: 17% by mass) Propylene-based polymer composition (a-2): Talc-containing block PP (manufactured by Prime Polymer Co., Ltd., properties of block PP: melting temperature: 178 °C, amount of decane-soluble part: 21% by mass, MFR 40 g / 10 min; talc content in the propylene-based polymer composition: 25% by mass)

[0095] [Production Example] <Production Example 1> Preparation of maleic anhydride graft-modified ethylene-1-butene copolymer (modified elastomer (b3-1)) Using the ethylene-1-butene copolymer shown in Table 1 below, maleic anhydride graft-modified ethylene-1-butene copolymer (modified elastomer (b3-1)) was produced.

[0096] [Table 1]

[0097] 10 kg of the above ethylene-1-butene copolymer and a solution prepared by dissolving 110 g of maleic anhydride and 6 g of 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexene-3 in 80 g of acetone were blended in a Henschel mixer. The obtained blend was put into a twin-screw melt-kneading extruder (manufactured by Nippon Steel Works, Ltd., screw diameter 30 mm, L / D = 42), and extruded in a strand form at a resin temperature of 260 °C and an extrusion rate of 7 kg / hour. Then, after water cooling, it was pelletized to obtain maleic anhydride graft-modified ethylene-1-butene copolymer (hereinafter also referred to as "modified elastomer"). The MFR (190 °C, 2.16 kg load) of the obtained modified elastomer was 0.6 g / 10 min, the MFR (230 °C, 2.16 kg load) was 1.2 g / 10 min, and the density was 866 kg / m 3 After extracting unreacted maleic anhydride with acetone, the graft amount of maleic anhydride measured was 0.99% by mass.

[0098] <Production Example 2> Preparation of Polyolefin Composition (b'-1) PA6 (nylon 6 resin, manufactured by Toray Industries, Inc., product name "Amilan CM1007", melting point 225 °C) was used as the aliphatic polyamide resin (b2), and the modified elastomer (b3-1) obtained in Production Example 1 was used as the modified elastomer (b3). These pellets were dry-blended so that PA6 / modified elastomer (b3-1) = 44.4 / 55.6% by mass, and then charged into a twin-screw melt-kneading extruder (manufactured by Nippon Steel Works, Ltd., screw diameter 30 mm, L / D = 42). Next, mixing was carried out under the conditions of a kneading temperature of 245 °C, an extrusion speed of 15 kg / hour, and a screw rotation speed of 200 revolutions / minute. Further, the mixed resin extruded using a pelletizer was cut to produce mixed resin pellets. Next, as the polyolefin (b1), polypropylene resin (b1-1) (homopolypropylene, manufactured by Prime Polymer Co., Ltd., product name "Prime Polypro J106G", melting point 163 °C) (hereinafter also referred to as "hPP") and the previously obtained mixed resin pellets were dry-blended so that hPP / mixed resin pellets = 55 / 45% by mass, and then charged into a twin-screw melt-kneading extruder (manufactured by Nippon Steel Works, Ltd., screw diameter 30 mm, L / D = 42). Next, mixing was carried out under the conditions of a kneading temperature of 245 °C, an extrusion speed of 15 kg / hour, and a screw rotation speed of 200 revolutions / minute. Further, the polyolefin composition extruded using a pelletizer was cut to produce pellets of the polyolefin composition (b'-1).

[0099] <Production Example 3> Preparation of Polyolefin Compositions (b-2-1), (b-2-2) In the same manner as in Production Example 2, mixed resin pellets were produced using PA6 and the modified elastomer (b3-1). Next, as the polyolefin (b1), a polypropylene resin (b1-1) and, as the acid-modified polypropylene (b4), maleic anhydride-modified polypropylene (b4-1) (manufactured by Mitsui Chemicals, Inc., product name "Admer AT2606", MFR: 220 g / 10 min (190 °C, 2.16 kg load), density 900 kg / m 3 ) and the previously obtained mixed resin pellets were dry-blended in the same manner as in Production Example 2 except that hPP / resin mixed pellets / maleic anhydride-modified polypropylene (b4-1) = 50 / 45 / 5 mass% (polyolefin composition (b-2-1)) or 40 / 45 / 15 mass% (polyolefin composition (b-2-2)) to produce pellets of the polyolefin compositions (b-2-1) and (b-2-2).

[0100] <Production Example 4> Preparation of Polyolefin Compositions (b-3-1) and (b-3-2) In the same manner as in Production Example 2, mixed resin pellets were produced using PA6 and the modified elastomer (b3-1). Next, as the polyolefin (b1), a polypropylene resin (b1-1) and, as the acid-modified polypropylene (b4), maleic anhydride-modified polypropylene (b4-2) (manufactured by Mitsui Chemicals, Inc., product name "Admer AT3190", MFR: 235 g / 10 min (190 °C, 2.16 kg load), density 900 kg / m 3 ) and the previously obtained mixed resin pellets were dry-blended in the same manner as in Production Example 2 except that hPP / resin mixed pellets / maleic anhydride-modified polypropylene (b4-1) = 50 / 45 / 5 mass% (polyolefin composition (b-3-1)) or 40 / 45 / 15 mass% (polyolefin composition (b-3-2)) to produce pellets of the polyolefin compositions (b-3-1) and (b-3-2).

[0101] [Example 1] (1) Preparation of Polypropylene Resin Composition As the propylene-based polymer composition (a), the propylene-based polymer composition (a-1) and the polyolefin composition (b), the polyolefin composition (b-2-1) obtained in Production Example 3 were dry-blended so as to have the formulation shown in Table 2, and then charged into a twin-screw melt kneading extruder (manufactured by Nippon Steel Works, Ltd., screw diameter 30 mm, L / D = 42). Next, mixing was carried out under the conditions of a kneading temperature of 200 °C, an extrusion speed of 15 kg / hour, and a screw rotation speed of 200 revolutions / minute. Further, the polypropylene resin composition extruded using a pelletizer was cut to produce pellets of the polypropylene resin composition.

[0102] (2) Preparation of test pieces for physical property measurement The pellets of the polypropylene resin composition obtained in (1) were charged into the hopper of an 80-ton injection molding machine (manufactured by Nissei Plastic Industrial Co., Ltd.), and test pieces for Charpy impact strength test and flexural modulus measurement were injection molded under the injection conditions of a set temperature of 200 °C and a mold temperature of 40 °C. Similarly, using a 70-ton injection molding machine (manufactured by Meiki Seisakusho Co., Ltd.), a square plate for punch impact test was injection molded under the injection conditions of a set temperature of 200 °C and a mold temperature of 40 °C.

[0103] (3) Charpy impact strength Under the following test conditions, a hammer was dropped from the back of the notch of the fixed test piece, and the impact strength was determined from the upward swing angle of the hammer after the test piece was broken and the lifting angle of the hammer before the test. (Test conditions) Test temperature: 23 °C, hammer capacity: 4 J, lifting angle: 149.9, test piece: notched, remaining width 8 mm, width 4 mm

[0104] (4) Evaluation of rigidity (measurement of flexural modulus) Using the test pieces obtained in (2) above, the flexural modulus was measured in accordance with JIS K7171. The results are shown in Table 2. This flexural modulus was measured while supporting the test piece with two supports (curvature radius 5 mm) having a span between supports (L) of 64 mm and applying a load at a speed of 2 mm / minute from the action point (curvature radius 5 mm) arranged at the center between the supports.

[0105] (5) Puncture Impact Test Measurements were carried out under the following test conditions to obtain the maximum impact force point displacement / energy and the puncture point displacement / energy. (Test Conditions) Test temperature: 23 °C, test speed 5 m / sec, striker diameter 0.5 inches, support base diameter 3 inches, test piece: injection-molded square plate with a thickness of approximately 1 mm The displacement at the point where the stress on the stress-displacement curve obtained in the test was the largest was defined as the maximum impact force point displacement, and the integral value of the curve from the start point of the test to that point was defined as the maximum impact force point energy. Also, the point where the displacement was larger than the maximum impact force point and the stress was half of that at the maximum impact force point was defined as the puncture point, the displacement at that point was defined as the puncture point displacement, and the integral value of the curve from the start point of the test to that point was defined as the puncture point energy.

[0106] [Example 2] The polyolefin composition (b) was changed to the polyolefin composition (b-2-2) obtained in Production Example 3, and pellets of the polypropylene resin composition were prepared and injection molding of test pieces for physical property measurement was carried out in the same manner as in Example 1, except that each component was adjusted to the blending ratio shown in Table 2, and evaluation was performed. The results are shown in Table 2.

[0107] [Example 3] The polyolefin composition (b) was changed to the polyolefin composition (b-3-1) obtained in Production Example 3, and pellets of the polypropylene resin composition were prepared and injection molding of test pieces for physical property measurement was carried out in the same manner as in Example 1, except that each component was adjusted to the blending ratio shown in Table 2, and evaluation was performed. The results are shown in Table 2.

[0108] [Example 4] The polyolefin composition (b) was changed to the polyolefin composition (b-3-2) obtained in Production Example 3, and pellets of the polypropylene resin composition were prepared and injection molding of test pieces for physical property measurement was carried out in the same manner as in Example 1, except that each component was adjusted to the blending ratio shown in Table 2, and evaluation was performed. The results are shown in Table 2.

[0109] [Comparative Examples 1-2] The propylene-based polymer composition (a) was changed to the propylene-based polymer composition (a-2), and further the polyolefin composition (b) was changed to the polyolefin composition (b'-1) obtained in Production Example 3. Except that each component was adjusted to the blending ratio shown in Table 2, pellets of the polypropylene resin composition were produced in the same manner as in Example 1, injection molding of test pieces for physical property measurement was carried out, and evaluation was performed. The results are shown in Table 2.

[0110] [Comparative Examples 3-4] The polyolefin composition (b) was changed to the polyolefin composition (b'-1) obtained in Production Example 3. Except that each component was adjusted to the blending ratio shown in Table 2, pellets of the polypropylene resin composition were produced in the same manner as in Example 1, injection molding of test pieces for physical property measurement was carried out, and evaluation was performed. The results are shown in Table 2.

[0111] [Comparative Example 5] The propylene-based polymer composition (a) was changed to the propylene-based polymer composition (a-2). Except that each component was adjusted to the blending ratio shown in Table 2, pellets of the polypropylene resin composition were produced in the same manner as in Example 1, injection molding of test pieces for physical property measurement was carried out, and evaluation was performed. The results are shown in Table 2.

[0112] [Comparative Example 6] The propylene-based polymer composition (a) was changed to the propylene-based polymer composition (a-2). Except that each component was adjusted to the blending ratio shown in Table 2, pellets of the polypropylene resin composition were produced in the same manner as in Example 3, injection molding of test pieces for physical property measurement was carried out, and evaluation was performed. The results are shown in Table 2.

[0113] [Table 2]

Claims

1. A polypropylene resin composition containing a propylene-based polymer composition (a) and a polyolefin composition (b), The propylene-based polymer composition (a) includes a propylene-based polymer (a1) and an inorganic filler (a2), and the amount of the decane-soluble part of the propylene-based polymer (a1) at room temperature (23°C) is 22 to 35% by mass based on the total mass of the propylene-based polymer (a1), The polyolefin composition (b) includes a polyolefin (b1), an aliphatic polyamide resin (b2), a modified elastomer (b3), and an acid-modified polypropylene (b4), The polypropylene resin composition has a continuous phase (α') containing a propylene-based polymer (a1), a polyolefin (b1), and an acid-modified polypropylene (b4), a dispersed inorganic filler (a2) in the continuous phase (α'), and a dispersed phase (β) containing an aliphatic polyamide resin (b2) and a modified elastomer (b3), The dispersed phase (β) is composed of a melt kneaded product of the aliphatic polyamide resin (b2) and the modified elastomer (b3), The modified elastomer (b3) is an elastomer in which a portion containing a group reactive with the aliphatic polyamide resin (b2) is added to an unmodified elastomer (b3'), and the unmodified elastomer (b3') is an olefinic thermoplastic elastomer containing a structural unit derived from ethylene and a structural unit derived from an α-olefin having 3 to 8 carbon atoms, or a styrenic thermoplastic elastomer containing a structural unit derived from a styrenic compound, A polypropylene resin composition, wherein when the total of the continuous phase (α') and the dispersed phase (β) is 100% by mass, the dispersed phase (β) is 80% by mass or less.

2. The polypropylene resin composition according to claim 1, wherein the propylene-based polymer (a1) is a propylene-ethylene block copolymer having a dispersed phase of an ethylene polymer block.

3. The polypropylene resin composition according to claim 1 or 2, wherein the inorganic filler (a2) is at least one inorganic filler selected from the group consisting of talc, mica, glass fiber, and calcium carbonate.

4. The polypropylene resin composition according to claim 1 or 2, wherein the polyolefin (b1) is a propylene homopolymer.

5. The polypropylene resin composition according to claim 1 or 2, wherein the aliphatic polyamide resin (b2) is at least one aliphatic polyamide resin selected from the group consisting of polyamide 6, polyamide 11, polyamide 12, polyamide 612, polyamide 610, and polyamide 1010.

6. The polypropylene resin composition according to claim 1 or 2, wherein the dispersed phase (β) has a continuous phase (β1) containing the aliphatic polyamide resin (b2) and a finely dispersed phase (β2) containing a modified elastomer (b3) dispersed in the continuous phase (β1).

7. The polypropylene resin composition according to claim 1 or 2, wherein the content of the propylene-based polymer composition (a) is 50 to 94.9 parts by mass, and the content of the polyolefin composition (b) is 5 to 49.9 parts by mass (provided that the total content of the propylene-based polymer composition (a) and the polyolefin composition (b) is 100 parts by mass).

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