Polypropylene resin composition

Abstract

To provide a polypropylene resin composition that is less prone to emit a bad odor and compares favorably in mechanical characteristics, moldability, and appearance quality with the conventional polypropylene resin composition comprising a biomass filler.SOLUTION: A polypropylene resin composition comprises a polypropylene resin (A), a biomass-derived synthetic resin (B), and a biomass-derived filler (C), with a biomass level of 20%-80%.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a polypropylene resin composition containing a biomass-derived synthetic resin and a biomass-derived filler.

Background Art

[0002] Polypropylene is widely used in various applications such as various industrial materials, automotive-related parts, various containers for medical and cosmetic use, daily necessities, films, and fibers due to its excellent heat resistance, moldability, transparency, and chemical resistance. On the other hand, in recent years, with the increasing demand for building a recycling-oriented society, in the material field, like energy, it is desired to move away from fossil fuels, and the utilization of biomass has attracted attention. Biomass is an organic compound synthesized from carbon dioxide and water, and by using it, it becomes carbon dioxide and water again, which is a so-called carbon-neutral renewable energy. In recent years, the practical application of resin compositions using these biomasses as raw materials has been rapidly progressing. For example, studies have been conducted on adding biomass-derived fillers to polypropylene (Patent Documents 1 and 2), and studies on adding biopolyethylene to polypropylene (Patent Documents 3 and 4) have been carried out.

[0003] When filling polypropylene with a biomass-derived filler to form a resin composition and molding this into various molded products, a processing temperature of about 180 to 200 °C is required. However, for example, when the filler ratio is a high filling amount of 30% by weight or more, at such a high temperature, a significant odor is generated from the biomass-derived filler, which poses a problem of having a great adverse impact on workers. If the processing temperature is lowered to suppress the generation of odor, the processing itself becomes difficult, or the appearance quality of the obtained molded product deteriorates, which becomes a problem.

[0004] Therefore, there is a demand for a polypropylene resin composition that contains a high ratio of biomass materials while achieving both suppression of odor generation and various mechanical properties, moldability, appearance quality, etc.

Prior Art Documents

[0005] [Patent Document 1] Japanese Patent Application Publication No. 6-80832 [Patent Document 2] Japanese Patent Publication No. 2021-50270 [Patent Document 3] Japanese Patent Publication No. 2019-34519 [Patent Document 4] Japanese Patent Publication No. 2016-27171 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] The object of the present invention is to provide a polypropylene resin composition containing a carbon-neutral biomass-derived resin and a biomass-derived filler, which suppresses odor generation and is comparable in mechanical properties, moldability, appearance quality, etc., to conventional resin compositions consisting only of polypropylene and biomass filler. [Means for solving the problem]

[0007] The polypropylene resin composition of the present invention is characterized by containing a polypropylene resin (A), a biomass-derived synthetic resin (B), and a biomass-derived filler (C), and having a biomass content of 20% to 80%.

[0008] The polypropylene resin composition preferably contains 20 parts by weight or more of polypropylene resin (A), 1 part by weight or more of biomass-derived synthetic resin (B), and 1 part by weight or more of biomass-derived filler (C) per 100 parts by weight.

[0009] The polypropylene resin (A) may be one or more polypropylene resins selected from the group consisting of propylene homopolymer, propylene-α-olefin random copolymer, and propylene-α-olefin block copolymer.

[0010] The biomass-derived synthetic resin (B) may be one or more plant-derived resins selected from the group consisting of biopolyethylene, biopolypropylene, and polylactic acid.

[0011] The biomass-derived filler (C) may be one or more plant-derived fillers selected from the group consisting of wood, pulp, cellulose fiber, bamboo, sugarcane (bagasse), rice husks, and rice (starch).

[0012] Furthermore, it is preferable that the molded articles, such as extruded articles, injection-molded articles, thermoformed articles, or blow-molded articles, are made from the polypropylene resin composition described above. [Effects of the Invention]

[0013] The polypropylene resin composition of the present invention, compared to conventional resin compositions consisting only of polypropylene and biomass fillers, suppresses odor generation and exhibits performance comparable to that of conventional compositions, even when having the same biomass ratio, in terms of mechanical properties, moldability, and appearance quality. [Modes for carrying out the invention]

[0014] (1) Polypropylene resin (A) Polypropylene resin (A) is a polymer of propylene and may be either a propylene homopolymer consisting only of propylene monomers, or a propylene-α-olefin copolymer obtained by copolymerizing propylene monomers with α-olefin as a comonomer. Examples of propylene-α-olefin copolymers include propylene-α-olefin random copolymers, propylene-α-olefin block copolymers, and propylene-α-olefin random block copolymers. Polypropylene resin (A) may be one type or a combination of two or more types.

[0015] In polypropylene resin (A), the α-olefin preferably refers to ethylene or an α-olefin having 4 to 18 carbon atoms. Specifically, examples include ethylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-heptene, 4-methylpentene-1, 4-methylhexene-1, 4,4-dimethylpentene-1, etc. In addition, the α-olefin may be one type or a combination of two or more types.

[0016] Propylene homopolymers can be obtained by homopolymerizing propylene in a single step or in a multi-step polymerization of two or more steps. Propylene-α-olefin random copolymers can be obtained by copolymerizing propylene and α-olefin in a single step or in a multi-step polymerization of two or more steps. Propylene-α-olefin block copolymers can be obtained by polymerization including a polymerization step (1) to obtain a propylene homopolymer by homopolymerizing propylene in a single step or in a multi-step polymerization of two or more steps, a copolymerization step (2-1) to obtain a propylene-α-olefin random copolymer by copolymerizing propylene and α-olefin in a single step or in a multi-step polymerization of two or more steps, or a copolymerization step (2-2) to obtain an inter-α-olefin random copolymer by copolymerizing two or more types of α-olefins in a single step or in a multi-step polymerization of two or more steps. Propylene-α-olefin random block copolymer can be obtained by polymerization comprising: copolymerization step (1) to obtain a propylene-α-olefin random copolymer obtained by copolymerizing propylene and α-olefin by single-stage polymerization or multi-stage polymerization of two or more stages; copolymerization step (2-1) to obtain a propylene-α-olefin random copolymer obtained by copolymerizing propylene and α-olefin by single-stage polymerization or multi-stage polymerization of two or more stages; or copolymerization step (2-2) to obtain an inter-α-olefin random copolymer obtained by copolymerizing two or more types of α-olefins by single-stage polymerization or multi-stage polymerization of two or more stages.

[0017] The polypropylene resin (A) is preferably one or more polypropylene resins selected from the group consisting of a propylene homopolymer, a propylene-ethylene block copolymer, a propylene-ethylene-1-butene block copolymer, a propylene-ethylene random copolymer, a propylene-1-butene random copolymer, a propylene-ethylene-1-butene random copolymer, a propylene-ethylene random block copolymer, and a propylene-ethylene-1-butene random block copolymer.

[0018] Examples of the polypropylene resin (A) include those polymerized by a Ziegler-Natta catalyst, those polymerized by a metallocene catalyst, and those polymerized by a post-metallocene catalyst. Examples of the Ziegler-Natta catalyst include a catalyst comprising a solid component containing titanium, magnesium, and halogen as essential components, an organoaluminum, and an electron donor used as needed. Examples of the metallocene catalyst include a catalyst comprising a transition metal compound of Group 4 of the periodic table containing a ligand having a cyclopentadienyl skeleton, a cocatalyst, and an organometallic compound and a carrier used as needed. Examples of the post-metallocene catalyst include a catalyst comprising an organometallic compound such as a bisamide compound of a Group 4 metal of the periodic table, a bisimino compound of a Group 8-10 metal of the periodic table, or a salicylaldiminato compound of a Group 4-10 metal of the periodic table, a cocatalyst, and an organometallic compound and a carrier used as needed. The polypropylene resin (A) can be a commercially available product, and for example, the Novatec PP series, WAYMAX series, etc. manufactured by Japan Polypropylene Corporation can be used.

[0019] The polypropylene resin (A) preferably has a melt flow rate (MFR) measured at 230°C under a load of 2.16 kg of 0.1 to 150 g / 10 min, more preferably 1 to 100 g / 10 min, and even more preferably 3 to 50 g / 10 min. When the MFR is within the above range, when extruding the sheet, the load on the extruder can be suppressed, the moldability is improved, which is preferable. Here, the MFR is a value measured at 230°C under a load of 2.16 kg in accordance with JIS K7210. The MFR of the polypropylene resin (A) can be adjusted by controlling the hydrogen concentration during polymerization and the like.

[0020] The polypropylene resin (A) preferably has a Q value (Mw / Mn) determined from the weight average molecular weight (Mw) and the number average molecular weight (Mn) measured by gel permeation chromatography (GPC) of 3 to 10, more preferably 3.5 to 8, and even more preferably 4 to 7. When the Q value of the polypropylene resin (A) is within the above range, during sheet extrusion molding, the moldability is particularly excellent, which is preferable. Here, the Q value is a value measured according to the conditions of the GPC measurement method described in JP-A-2021-59677.

[0021] It is preferable to blend the polypropylene resin (A) with high melt tension polypropylene. High melt tension polypropylene suppresses the sagging of the sheet during sheet extrusion, further suppresses the sagging of the sheet during secondary molding, and contributes to uniform elongation during stretching, so the processability is good. High melt tension polypropylene preferably has a melt tension (MT) represented by the following formula. The melt tension (MT, unit: cN) is Preferably, log(MT) > -0.9×log(MFR) + 0.5, and satisfies log(MT) < 1.40 (MT < 25), More preferably, log(MT) > -0.9×log(MFR) + 0.6, and satisfies log(MT) < 1.04 (MT < 11), Even more preferably, log(MT) > -0.9×log(MFR) + 0.7, The following conditions must be met: log(MT) < 0.85 (MT < 7). Examples of these materials include WAYMAX from Nippon Polypropylene and Dploy from Borealis.

[0022] Here, the melt tension (MT) is a value measured using a capillary graph. The resin is heated to 230°C and placed in a 9.6 mm diameter cylinder to melt it. The molten resin is then extruded through an orifice with a diameter of 2.0 mm and a length of 40 mm at an extrusion speed of 20 mm / min. The tension (in cN) detected in the pulley when the extruded resin is withdrawn at a speed of 4.0 m / min is measured and defined as the melt tension (MT).

[0023] High melt-tension polypropylene can be obtained, for example, by electron beam crosslinking, crosslinking using peroxides, introducing long-chain branching during polymerization, or broadening the molecular weight distribution.

[0024] The polypropylene resin (A) contained in the polypropylene resin composition of the present invention is not a polypropylene resin derived from biomass.

[0025] (2) Biomass-derived synthetic resin (B) In the polypropylene resin composition of the present invention, the biomass-derived synthetic resin (B) is obtained by polymerizing biomass-derived monomers. The biomass-derived monomers are polymerizable organic compounds derived from organic resources of plants and animals, excluding fossil resources, and preferably polymerizable organic compounds derived from organic resources of plants, excluding fossil resources. The biomass-derived (co)monomer does not have to contain 100% biomass-derived components, but it is preferable that the bio-content, as described later, is 80% or more, and particularly preferable that it is 90% or more. This is because the environmental burden can be reduced by making a portion of the (co)monomer a biomass-derived component.

[0026] Examples of synthetic resins for biomass-derived synthetic resin (B) include biomass-derived thermoplastic resins obtained by polymerizing biomass-derived monomers. Homopolymers obtained by homopolymerizing biomass-derived monomers, or copolymers obtained by copolymerizing biomass-derived monomers with comonomers such as α-olefins, can also be used. The number of carbon atoms in the α-olefin is not particularly limited, but typically those with 3 to 20 carbon atoms can be used, and 1-butene, 1-hexene, or 1-octene are preferred. Furthermore, petroleum-derived monomers may also be included.

[0027] Representative biomass-derived resins include polylactic acid, biopolyethylene, biopolypropylene, biopolyamide 11, biopolyamide 1010, and biopolybutylene succinate.

[0028] The ratio of biomass-derived carbon to the total carbon content in biomass-derived resin (B) is called the bio-degree, and is the amount of carbon contained in the resin. 14 This can be determined by measuring the concentration of C. That is, a certain percentage of C is present in the atmosphere. 14 While C is included, the carbon in petroleum-derived resins is 14 Since C is not included, it is contained in biomass-derived resin (B) 14 The bio-concentration can be determined by measuring the concentration of C. For example, if all the carbon in a biomass-derived resin (B) is petroleum-derived, the bio-concentration is 0%, and if all the carbon is biomass-derived, the bio-concentration is 100%. The bio-concentration (%) can be measured and calculated according to ASTM D6866.

[0029] In the present invention, the biomass content (%) of the polypropylene resin composition is a weighted average of the bio-content (%) of the polypropylene resin (A), the bio-content (%) of the biomass-derived resin (B), the bio-content (%) of the biomass-derived filler (C), and the bio-content (%) of the optional components, a thermoplastic elastomer (D) and a compatibilizer (E), and is a value calculated by the following formula. Biomass percentage (%) = Σ[{ai × (bi ÷ 100)} / c × 100] The subscript i represents the numbers 1 through 5, and ai, bi, and c represent the following, respectively. a1: Weight of polypropylene resin (A) a2: Weight of biomass-derived resin (B) a3: Weight of biomass-derived filler (C) a4: Weight of optional thermoplastic elastomer (D) a5: Weight of the optional component, compatibilizer (E) b1: Bio-concentration (%) of polypropylene resin (A), b1=0 b2: Bio-concentration (%) of biomass-derived resin (B) b3: Bio-concentration (%) of biomass-derived filler (C) b4: Bio-concentration (%) of the optional component thermoplastic elastomer (D), b4=0 b5: Bio-concentration (%) of the optional component compatibilizer (E), b5=0 c: Weight of the polypropylene resin composition Furthermore, the bio-concentration (%) of biomass-derived filler (C) can be measured and calculated using ASTM D6866, similar to the bio-concentration (%) of biomass-derived resin (B). Similarly, the bio-concentration (%) of polypropylene resin (A), thermoplastic elastomer (D), and compatibilizer (E) can also be measured and calculated using ASTM D6866, even for trace amounts. 14 In some cases, detecting C may result in the biomass content not being 0% (for example, 0.1-5.0%), but in this patent, such components are determined not to be biomass-derived and are calculated as 0%. Here, the weight of the polypropylene resin composition is given by c = a1 + a2 + a3 + a4 + a5.

[0030] (3) Biomass-derived filler (C) Biomass-derived fillers (C) are organic resources derived from plants and animals, excluding fossil resources, and preferably are organic resources derived from plants, excluding fossil resources. Examples of organic resources derived from plants, excluding fossil resources, include lignocellulose materials, cellulose materials, and starch materials.

[0031] Lignocellulosic materials include lignocellulosic fibers and lignocellulosic powders. Specifically, these include wood pulp, refiner graft pulp (RGP), paper pulp, recycled paper, crushed wood chips, wood flour, and fruit shell powder. Specific examples of wood flour include crushed pine, fir, poplar, bamboo, bagasse, oil palm trunks, sawdust, and wood shavings, while fruit shell powders include crushed walnuts, peanuts, and coconuts.

[0032] Examples of cellulose-based materials include alpha fiber flocks obtained by alkali-treating and mechanically shredding wood pulp, cotton linters and cotton flocks obtained from cottonseed, rayon flocks obtained by shredding rayon, and cellulose fibers.

[0033] There are no particular restrictions on the shape of these lignocellulose-based and cellulose-based materials; fibrous or powdered forms can be used.

[0034] The lignocellulose material or cellulose material may be an esterified lignocellulose material or esterified cellulose material obtained by adding a polybasic acid anhydride to the hydroxyl group of the lignocellulose material or cellulose material; an oligoesterified lignocellulose material or oligoesterified cellulose material obtained by adding a polybasic acid anhydride and a monoepoxy compound to the hydroxyl group of the lignocellulose material or cellulose material; or an oligoesterified lignocellulose material or oligoesterified cellulose material obtained by adding a polybasic acid anhydride and a polyhydric alcohol to the hydroxyl group of the lignocellulose material or cellulose material.

[0035] Examples of polybasic acid anhydrides include maleic anhydride, succinic anhydride, phthalic anhydride, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, dichloromaleic anhydride, itaconic anhydride, tetrabromophthalic anhydride, hettic anhydride, trimetic anhydride, pyromellitic anhydride, etc., but maleic anhydride, succinic anhydride, and phthalic anhydride are particularly preferred because they are industrially advantageous and inexpensive.

[0036] Any monoepoxy compound can be a compound containing one epoxy group in its molecule, such as phenyl glycidyl ether, allyl glycidyl ether, styrene oxide, octylene oxide, methyl glycidyl ether, butyl glycidyl ether, cresyl glycidyl ether, etc.

[0037] Examples of polyhydric alcohols include ethylene glycol, propylene glycol, trimethylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, pinacol, hydrobenzoin, benzpinacol, cyclopentane-1,2-diol, cyclohexane-1,2-diol, cyclohexane-1,4-diol, glycerin, polyethylene glycol 400, and the like.

[0038] A common method for esterification involves mixing the polybasic acid anhydride (or the polybasic acid anhydride with the monoepoxy compound, or the polybasic acid anhydride with the polyhydric alcohol) in the presence of a lignocellulose material or a cellulosic material and reacting them at a temperature of 60 to 150°C for 0.5 to 8 hours.

[0039] In the reaction in which the polybasic acid anhydride and the monoepoxy compound are alternately added and esterified to hydroxyl groups in lignocellulose or cellulosic materials, the reaction proceeds sufficiently even without a catalyst. However, basic catalysts such as sodium carbonate, dimethylbenzylamine, tetramethylammonium chloride, and pyridine may be used to accelerate the reaction. Alternatively, an addition esterification catalyst may be used.

[0040] Furthermore, the molecular weight of the oligomers of the polybasic acid anhydride and the monoepoxy compound is preferably about 20 to 1000 (preferably with a degree of polymerization of 5 or less, including 1) so that they can be liquid, from the viewpoint of ease of use and effectiveness.

[0041] Furthermore, the proportions of the polybasic acid anhydride and the monoepoxy compound are as follows. First, the polybasic acid anhydride is preferably used in an amount of 5 to 120 parts by mass, more preferably 10 to 100 parts by mass, per 100 parts by mass of the dried lignocellulose-based material or cellulose-based material. Then, the monoepoxy compound is preferably used in an amount of 0.5 to 2.0 equivalents of epoxy groups per equivalent of acid groups of the polybasic acid anhydride. This is preferable because using 120 parts by mass or less of the polybasic acid anhydride per 100 parts by mass of the dried lignocellulose-based material or cellulose-based material maintains the content of the lignocellulose-based material or cellulose-based material, thereby suppressing seepage during hot-press molding. It is also preferable to use 5 parts by mass or more to ensure hot-press fluidity and to make it easier to obtain a uniform molded product.

[0042] In the case of a reaction in which the hydroxyl groups of a lignocellulose-based material or a cellulosic material are alternately added and esterified with the polybasic acid anhydride and the polyhydric alcohol, the aforementioned monoepoxy compound may be replaced with the polyhydric alcohol.

[0043] Specific examples of starch-based materials include, for example, rice, wheat, corn, sugarcane, potatoes, sweet potatoes, tapioca, corn starch, potato starch, potato starch, tapioca starch, and their mildly acetylated derivatives. Any agricultural product containing starch can be used, and the list is not limited to these. Furthermore, these starch-based materials can be used in their typical storage state, or after simple pre-treatment such as washing, removing starch-free parts like the outer skin, or cutting into appropriate sizes. Starch-based materials are usually obtained in granular form, and these can be used as is.

[0044] Furthermore, it is even preferable that the starch-based material used as a raw material undergoes gelatinization treatment in the manner described below after such simple pretreatment. The starch that makes up the starch-based material initially has a crystalline structure (β structure), but when heated in the presence of an appropriate amount of water or a hydrophilic plasticizer such as glycerin, this β structure breaks down and changes to an amorphous structure (α structure). This change from a β structure to an α structure when raw starch is heated with hydrophilic components is called gelatinization. Compared to the case of starch with a β structure, starch granules exhibiting this α structure are more easily broken down at the molecular level and dispersed finely and uniformly in the heat-fluid polypropylene resin.

[0045] Furthermore, it is preferable that trehalose is dissolved in the hydrophilic plasticizer used to convert starch having a β structure to an α structure, as described above. The effect of this is that, for example, when rice is used as a starch-based material, the trehalose aqueous solution impregnates the raw rice, and the trehalose suppresses the decomposition of the lipid components of the rice, thereby suppressing the deterioration of the polypropylene resin composition made using the rice over time. This is because trehalose has the effect of coating the rice components and protecting fatty acids from oxidative decomposition.

[0046] Such effects are not limited to rice but can also be observed in general starch-based materials. In addition to trehalose mentioned above, other materials with such effects include salt, sucrose, antioxidants, protein degradation accelerators, and cellulose degradation accelerators. Furthermore, by adding these to a hydrophilic plasticizer to create an α-structured starch-based material, it is possible to prevent the characteristic odor, charring, and discoloration of the manufactured polypropylene resin composition.

[0047] Up to this point, we have explained that starch-based materials that have already undergone gelatinization treatment are used as raw materials. However, as will be explained later, starch-based materials with a beta structure that contain moisture can also be used.

[0048] Specifically, raw rice is soaked in water for a predetermined time, drained, and then placed in a kneader along with polypropylene resin, where it is kneaded at the thermal fluid temperature of the polypropylene resin. This thermal fluid temperature (usually 100-170°C) is sufficient to change the starch structure of raw rice from a β structure to an α structure, so the raw rice is gelatinized during the kneading process. After the raw rice has changed to an α structure, as already mentioned above, the starch molecular chains break down, become finer, and are dispersed in the matrix of the polypropylene resin.

[0049] Here, for raw rice with a β structure to be heated and converted to an α structure, a moisture content of 17% by mass or more is desirable, and for this purpose, it is preferable to soak it in water for 5 minutes or more. Furthermore, for starch-based materials that contain enough moisture to convert their starch to an α structure on their own, such as potatoes, there is no need to soak them in water as with rice, and they can be put directly into the kneader.

[0050] The biomass-derived filler (C) is preferably one or more plant-derived fillers selected from the group consisting of wood, pulp, cellulose fiber, bamboo, sugarcane (bagasse), rice husks, and rice (starch).

[0051] The biomass-derived filler (C) has an average particle size of preferably 5 to 300 μm, more preferably 10 to 200 μm. Within this range, secondary aggregation due to a small average particle size is less likely to occur during kneading, thus suppressing a decrease in physical properties and moldability. Furthermore, within this range, the occurrence of holes during extrusion molding and thermoforming due to a large average particle size is suppressed.

[0052] Here, the average particle size is a value measured using a laser diffraction particle size distribution analyzer, and is defined as the value at which the cumulative value of the volume accumulation distribution reaches 50%. An example of such a measuring device is the LA-920 model manufactured by Horiba, Ltd.

[0053] (4) Thermoplastic elastomer (D) The polypropylene resin composition may optionally contain a thermoplastic elastomer (D). Examples of thermoplastic elastomers (D) include olefin-based elastomers and styrene-based elastomers. These can be used individually or in combination of two or more.

[0054] Examples of olefin-based elastomers include ethylene-propylene copolymer elastomers (EPR), ethylene-butene copolymer elastomers (EBR), ethylene-hexene copolymer elastomers (EHR), ethylene-octene copolymer elastomers (EOR), ethylene-propylene-ethylidene norbornene copolymers, ethylene-propylene-butadiene copolymers, ethylene-propylene-isoprene copolymers, and other ethylene-α-olefin-diene ternary copolymer elastomers, as well as hydrogenated polymer elastomers such as ethylene-ethylene-butylene-ethylene copolymer (CEBC). Among these, ethylene-propylene copolymer elastomers, ethylene-butene copolymer elastomers, and ethylene-hexene copolymer elastomers are preferred.

[0055] Examples of styrene-based elastomers include styrene-butadiene-styrene triblock copolymer elastomer (SBS), styrene-isoprene-styrene triblock copolymer elastomer (SIS), styrene-ethylene-butylene copolymer elastomer (SEB), styrene-ethylene-propylene copolymer elastomer (SEP), styrene-ethylene-butylene-styrene copolymer elastomer (SEBS), styrene-ethylene-butylene-ethylene copolymer elastomer (SEBC), hydrogenated styrene-butadiene elastomer (HSBR), styrene-ethylene-propylene-styrene copolymer elastomer (SEPS), styrene-ethylene-ethylene-propylene-styrene copolymer elastomer (SEEPS), styrene-butadiene-butylene-styrene copolymer elastomer (SBBS), partially hydrogenated styrene-isoprene-styrene copolymer elastomer, and partially hydrogenated styrene-isoprene-butadiene-styrene copolymer elastomer.

[0056] The thermoplastic elastomer (D) preferably has an MFR of 0.1 to 10 g / 10 min, measured at 230°C and a 2.16 kg load. When the MFR of the thermoplastic elastomer (D) is 0.1 g / 10 min or higher, the load on the extruder is reduced when extruding the sheet, improving productivity. Furthermore, when the MFR is 10 g / 10 min or lower, the melt tension of the sheet can be maintained at a high level, and the molded body does not sag under its own weight during extrusion molding or thermoforming, which is preferable.

[0057] (5) Compatibilizer (E) In polypropylene resin compositions, a compatibilizer (E) may be added as needed. Preferred compatibilizers (E) include saturated carboxylic acids, unsaturated carboxylic acids or their derivatives, thermoplastic resins modified with unsaturated carboxylic acids or their derivatives, and cellulose-based materials, lignocellulose-based materials, and starch-based materials modified with unsaturated carboxylic acids or their derivatives. Furthermore, oil-modified alkyd resins or their derivatives, modified starch or their derivatives may also be used.

[0058] Examples of saturated carboxylic acids include succinic anhydride, succinic acid, phthalic anhydride, phthalic acid, tetrahydrophthalic anhydride, and adipic anhydride. Examples of unsaturated carboxylic acids include maleic anhydride, maleic acid, nadic anhydride, itaconic anhydride, itaconic acid, citraconic anhydride, citraconic acid, crotonic acid, isocrotonic acid, mesaconic acid, angelic acid, sorbic acid, and acrylic acid. Derivatives of saturated or unsaturated carboxylic acids can include metal salts, amides, imides, and esters of saturated or unsaturated carboxylic acids.

[0059] Furthermore, as the compatibilizer (E), thermoplastic resins modified with unsaturated carboxylic acids or their derivatives, as well as cellulose-based materials, lignocellulose-based materials, starch-based materials, etc., modified with unsaturated carboxylic acids or their derivatives, can be used. The thermoplastic resin used in the thermoplastic resin modified with unsaturated carboxylic acids or their derivatives is not particularly limited as long as it does not significantly impair the effects of the present invention. Specifically, examples include low-density polyethylene, ethylene-α-olefin copolymer, high-density polyethylene, polypropylene, propylene block copolymer, propylene random copolymer, etc. Of these, it is preferable that it be the same as the polypropylene resin (A).

[0060] The compatibilizer (E) is obtained by heating and mixing a thermoplastic resin as the base material with an unsaturated carboxylic acid or its derivative and a radical generator in the presence or absence of a solvent. The amount of unsaturated carboxylic acid or its derivative added is preferably 0.1 to 10% by mass, and particularly preferably 0.5 to 5% by mass. As the compatibilizer (E) used in the present invention, a thermoplastic resin modified with an unsaturated carboxylic acid or its derivative that is odorless and has low acidity is preferred.

[0061] (6) Polypropylene resin composition The polypropylene resin composition of the present invention contains a polypropylene resin (A), a biomass-derived synthetic resin (B), and a biomass-derived filler (C). The polypropylene resin composition of the present invention has a biomass content of 20% to 80%, preferably 30% to 70%, and more preferably 40% to 60%.

[0062] The composition ratio of the polypropylene resin composition of the present invention is preferably such that, per 100 parts by weight of the polypropylene resin composition, it contains 20 parts by weight or more of polypropylene resin (A), 1 part by weight or more of biomass-derived synthetic resin (B), and 1 part by weight or more of biomass-derived filler (C), and more preferably 40 parts by weight or more of polypropylene resin (A), 10 parts by weight or more of biomass-derived synthetic resin (B), and 10 parts by weight or more of biomass-derived filler (C). Here, 100 parts by weight of the polypropylene resin composition is the sum of the essential components consisting of polypropylene resin (A), biomass-derived synthetic resin (B), and biomass-derived filler (C), and the optional components consisting of thermoplastic elastomer (D) and compatibilizer (E). Here, when the polypropylene resin composition contains other synthetic resins other than polypropylene resin (A) and biomass-derived synthetic resin (B), and / or other fillers other than biomass-derived filler (C), the amounts of these other synthetic resins and other fillers are not included in 100 parts by weight of the polypropylene resin composition. By replacing a portion of the polypropylene in a resin composition with a biomass-derived resin, compared to conventional resin compositions consisting only of polypropylene and biomass-derived fillers, it is possible to improve the biomass ratio of the resin composition while maintaining comparable performance in terms of mechanical properties, moldability, and appearance quality. Alternatively, by replacing a portion of the biomass filler in a resin composition with a biomass-derived resin, it is possible to maintain the biomass ratio while suppressing odor generation and maintaining comparable performance in terms of mechanical properties, moldability, and appearance quality.

[0063] When the polypropylene resin composition contains a thermoplastic elastomer (D), the proportion of the thermoplastic elastomer is preferably 1 part by weight or more, more preferably 5 parts by weight or more, per 100 parts by weight of the polypropylene resin composition.

[0064] When the polypropylene resin composition contains a compatibilizer (E), the composition ratio of the compatibilizer (E) is preferably 0.1 to 15% by mass, and particularly preferably 1 to 10% by mass, per 100 parts by weight of the polypropylene resin composition.

[0065] Polypropylene resin (A), biomass-derived synthetic resin (B), and biomass-derived filler (C) may contain at least one of each constituent component, and may contain only one or two or more.

[0066] The polypropylene resin composition may optionally contain various additives, such as nucleating agents, heat stabilizers, antioxidants, weather stabilizers, light stabilizers, ultraviolet absorbers, antistatic agents, slip agents, antiblocking agents, antifogging agents, neutralizing agents, metal deactivators, surfactants, compatibilizers, colorants, antibacterial and antifungal agents, flame retardants, plasticizers, dispersants, fillers, conductive agents, preservatives, fragrances, deodorizers, insecticides, etc., to the extent that the effects of the present invention are not significantly impaired. Two or more of these optional components may be used in combination.

[0067] Methods for preparing the propylene resin composition of the present invention include mixing powdered or pelletized polypropylene resin (A), biomass-derived resin (B), biomass-derived filler (C), and other compounding agents as needed, using a dry blender, Henschel mixer, or the like. Depending on the situation, the biomass-derived filler (C) may be pre-fixed to the polypropylene resin (A) and / or biomass-derived resin (B) by methods such as galvanization. Alternatively, these can be kneaded using a single-screw or twin-screw extruder, or kneaded with a high filler content to form a masterbatch, which can then be diluted to the required concentration during molding.

[0068] The polypropylene resin composition of the present invention can be produced by mixing a polypropylene resin (A), a biomass-derived resin (B), a biomass-derived filler (C), and any optional components, or by heating and kneading them using a single-screw extruder, twin-screw extruder, etc. The resin temperature for heating and kneading can be appropriately determined within the range of 100°C to 300°C, taking into consideration the kneading load, the color and odor of the resin composition, etc.

[0069] The polypropylene resin composition of the present invention can be molded into various desired shapes by means of pressure molding, film molding, vacuum molding, extrusion molding, injection molding, etc., to produce various molded products. The molding temperature can be appropriately determined within the range of 100°C to 300°C, taking into consideration the mixing load, the color and odor of the resin composition, etc.

[0070] The polypropylene resin composition of the present invention can be effectively used as a material for various film and sheet materials, disposable molded products (e.g., containers, pipes, square timbers, rods, artificial wood, trays, concrete panels, foams, etc.), furniture, building materials, interior and exterior materials for automobiles, housings for home appliances, civil engineering and construction materials, materials for agriculture, dairy farming, and fisheries, recreational materials, sports equipment, and the like.

[0071] Furthermore, the polypropylene resin composition of the present invention is also suitably used in fields such as electrical insulating materials, industrial component materials, and building materials, and is particularly suitable as a raw material for housing components, building materials, and home appliances. Specific examples include trays, tableware, speakers, bathroom unit floor pans, buckets, toilet seats, cabinets, stereo cabinets, baseboards, door materials, counter materials, window frames, sound insulation panels, shelves, civil engineering timbers, columns, structural materials, kitchen components, floors, baths, underlayment, piano and organ baseboards, and joinery ceiling materials.

[0072] According to the polypropylene resin composition of the present invention, even with the same biomass ratio as conventional polypropylene resin compositions containing biomass fillers, odor generation is suppressed, and a polypropylene resin composition that is comparable in mechanical properties, moldability, appearance quality, etc., can be obtained. [Examples]

[0073] The present invention will be described in more detail below using examples, but the present invention is not limited to these examples.

[0074] 1. Evaluation Method (1) Pellet odor 100g of pellets were weighed, sealed in a 500ml glass container, and held at 80°C for 3 hours. After that, the lid of the glass container was opened, and the odor of the pellets inside was evaluated sensory. The intensity of the odor was judged by five panelists, who scored according to the following criteria, and the average of the five judged values ​​(rounded to the first decimal place) was used as the result. 1: It smells very strong. To the point of being unbearable. 2: It smells quite strong. You can clearly identify what the smell is. 3: I can clearly identify the smell, but it's not unpleasant. 4. If you smell it carefully, you can figure out what it smells like. 5: Almost no smell at all. Only a faint scent.

[0075] (2) Thermoformability The pellets were fed into an extruder with a screw diameter of 40 mm, extruded through a T-type die at a resin temperature of 200°C, and then sandwiched between mirror-finished metal cast rolls with a surface temperature of 60°C. The extruded continuously at a speed of 1.2 m / min while cooling and solidifying to obtain a sheet of polypropylene resin composition with a width of 500 mm and a thickness of 1.0 mm.

[0076] The obtained sheet was cut to 40cm x 40cm, and a container was thermoformed using a deep-drawing mold for a cup-shaped container (upper inner diameter 10.8cm, depth 8cm) using a multi-purpose thermoforming machine (manufactured by Asano Research Institute Co., Ltd., small multi-functional vacuum pressure forming machine) with a heater temperature of 450°C and compressed air pressure of 0.5MPa. The heating time was set to 8 levels in 2-second increments within the range of 18 to 32 seconds.

[0077] The moldability of the thermoformed product was evaluated based on (i) the wide range of heating times during which it could be thermoformed, and (ii) the appearance of the container. The criteria for determining moldability were as follows: (i) Wide range of heating times for thermoforming ◎: The container shape can be reproduced (the container can be molded to the container shape) with three or more heating time levels. ○: Two heating times are available to reproduce the container shape. △: One level of heating time required to reproduce the container shape. ×: Container shape cannot be reproduced at all heating times. (ii) Appearance of the container (visual inspection) ○: No irregularities or patterns can be observed on the surface. △: Slight irregularities or patterns can be observed on the surface. ×: Surface texture, patterns, etc. are clearly visible.

[0078] (3) Tensile modulus Using a molding machine (Toshiba Machine Co., Ltd. EC20 injection molding machine) and the following molds, flat plate-shaped test specimens for physical property evaluation were prepared under the following conditions. • Mold = Cavities for two flat test pieces (10 x 80 x 4t (mm)) for physical property evaluation. Molding conditions: Molding temperature 220°C, mold temperature 30°C, injection pressure 50 MPa, injection time 5 seconds, cooling time 20 seconds. The prepared flat test specimens were measured at a test temperature of 23°C in accordance with JIS K7162. The evaluation results of the tensile modulus are shown in Table 1.

[0079] (4) Impact resistance Using the flat test specimens prepared in (3) above, measurements were taken at a test temperature of 23°C in accordance with JIS K7111. The evaluation results of the Charpy impact strength are shown in Table 1.

[0080] 2. Raw materials The raw materials used in the evaluation are as follows: • Polypropylene resin (A-1): WAYMAX EX4000 (product name) manufactured by Nippon Polypropylene Co., Ltd., MFR: 6.0g / 10 min (230℃, 2.16kg), Bio content: 0%, Mw / Mn: 6.87, Melt tension: 4cN • Biomass-derived synthetic resin (B-1): GreenPE SGD4960 (product name) manufactured by Braskem, low-density polyethylene, density: 0.915 g / cm³ 3 MFR: 30g / 10 minutes (190℃, 2.16kg), Bio-concentration: 95%. • Biomass-derived filler (C-1): Cedar wood powder (50 mesh) manufactured by Casino Co., Ltd. (product name), bio content: 100%. • Thermoplastic elastomer (D-1): Toughmer A0550S (product name), manufactured by Mitsui Chemicals, Density: 0.860 g / cm³ 3 MFR: 1.0g / 10 min (230℃, 2.16kg), Bio content: 0%. • Compatibilizer (E-1): Maleic anhydride-modified polypropylene, manufactured by Sanyo Chemical Industries, Ltd., Yumex 1001 (product name), Bio content: 0%, Melting point: 142℃, Acid value: 26 mg KOH / g, Weight-average molecular weight (Mw): 45,000 g / mol

[0081] (Example 1, Comparative Examples 1-2) For the three polypropylene resin compositions shown in Table 1 (Example 1, Comparative Examples 1-2), each raw material was weighed and uniformly mixed using a ribbon blender. The resulting mixture was fed into a twin-screw extruder with a screw diameter of 15 mm, kneaded at a resin temperature of 200°C, extruded into strands, water-cooled, and pelletized to obtain the polypropylene resin composition.

[0082] The pellet odor, vacuum formability, tensile modulus, and Charpy impact strength of the obtained polypropylene resin composition were evaluated using the method described above. The evaluation results are summarized in Table 1.

[0083] [Table 1]

Claims

1. A polypropylene resin composition comprising a polypropylene resin (A), a biomass-derived synthetic resin (B) which is at least one plant-derived resin selected from the group consisting of biopolyethylene and biopolypropylene, a biomass-derived filler (C) with an average particle size of 5 μm or more and 300 μm or less, and an olefin-based elastomer in which the bio content, as measured and calculated by ASTM D6866, is 5.0% or less or 14C is not detected, wherein in 100 parts by weight of the polypropylene resin composition, the biomass-derived filler (C) is 1 part by weight or more and 30 parts by weight or less, the olefin-based elastomer is 5 parts by weight or more, and the biomass content is 30% to 80%.

2. A polypropylene resin composition comprising a polypropylene resin (A), a biomass-derived synthetic resin (B) which is at least one plant-derived resin selected from the group consisting of biopolyethylene and biopolypropylene, a biomass-derived filler (C) with an average particle size of 5 μm or more and 300 μm or less, a thermoplastic elastomer (D) which has a bio content of 5.0% or less or in which 14C is not detected as measured and calculated by ASTM D6866, and a compatibilizer (E) which is a thermoplastic resin modified with an unsaturated carboxylic acid or its derivative which has a bio content of 5.0% or less or in which 14C is not detected as measured and calculated by ASTM D6866, wherein in 100 parts by weight of the polypropylene resin composition, the biomass-derived filler (C) is 1 part by weight or more and 30 parts by weight or less, the thermoplastic elastomer (D) is 5 parts by weight or more, and the biomass content is 30% to 80%.

3. A polypropylene resin composition comprising only a polypropylene resin (A), a biomass-derived synthetic resin (B), a biomass-derived filler (C) with an average particle size of 5 μm or more and 300 μm or less, an olefin-based elastomer with a bio content of 5.0% or less or no detectable 14C as measured and calculated by ASTM D6866, and a compatibilizer (E) which is a thermoplastic resin modified with an unsaturated carboxylic acid or its derivative with a bio content of 5.0% or less or no detectable 14C as measured and calculated by ASTM D6866, wherein in 100 parts by weight of this polypropylene resin composition, the biomass-derived filler (C) is 1 part by weight or more and 30 parts by weight or less, the olefin-based elastomer is 5 parts by weight or more, and the biomass content is 20% to 80%.

4. The polypropylene resin composition according to claim 1, comprising 20 parts by weight or more of polypropylene resin (A), 1 part by weight or more of biomass-derived synthetic resin (B), 1 part by weight or more of biomass-derived filler (C), and 5 parts by weight or more of olefin-based elastomer in 100 parts by weight of the polypropylene resin composition.

5. The polypropylene resin composition according to claim 2, wherein 100 parts by weight of the polypropylene resin composition contains 20 parts by weight or more of polypropylene resin (A), 1 part by weight or more of biomass-derived synthetic resin (B), 1 part by weight or more and 30 parts by weight or less of biomass-derived filler (C), 5 parts by weight or more of thermoplastic elastomer (D), and 0.1 to 15 parts by weight of a compatibilizer (E), which is a thermoplastic resin modified with an unsaturated carboxylic acid or a derivative thereof.

6. The polypropylene resin composition according to claim 3, comprising 20 parts by weight or more of polypropylene resin (A), 1 part by weight or more of biomass-derived synthetic resin (B), 1 part by weight or more of biomass-derived filler (C), 30 parts by weight or more of biomass-derived filler (C), 5 parts by weight or more of olefin-based elastomer, and 0.1 to 15 parts by weight of a compatibilizer (E) which is a thermoplastic resin modified with an unsaturated carboxylic acid or a derivative thereof, per 100 parts by weight of the polypropylene resin composition.

7. The polypropylene resin composition according to claim 3 or 6, wherein the biomass-derived synthetic resin (B) is one or more plant-derived resins selected from the group consisting of biopolyethylene, biopolypropylene, and polylactic acid.

8. The polypropylene resin composition according to any one of claims 1 to 7, wherein the polypropylene resin (A) is one or more polypropylene resins selected from the group consisting of propylene homopolymer, propylene-α-olefin random copolymer, and propylene-α-olefin block copolymer.

9. The polypropylene resin composition according to any one of claims 1 to 8, wherein the biomass-derived filler (C) is one or more plant-derived fillers selected from the group consisting of wood, pulp, cellulose fiber, bamboo, sugarcane (bagasse), rice husk, and rice (starch).

10. A molded article comprising the polypropylene resin composition according to any one of claims 1 to 9.

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