Polypropylene resin composition

Abstract

To provide a polypropylene-based resin composition capable of containing a filler in a high concentration and having high rigidity and excellent heat resistance.SOLUTION: There is provided a polypropylene-based resin composition which comprises a polypropylene-based resin, a filler, a filler dispersant and / or a filler-binder, wherein the content ratio of the filler in the polypropylene-based resin composition is 20 to 70 wt.%. The filler dispersant is at least one selected from the group consisting of a polyhydric alcohol fatty acid ester, a fatty acid amide, a polyglycerol fatty acid ester, a condensed hydroxy fatty acid and an alcohol ester of a condensed hydroxy fatty acid.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a polypropylene resin composition. [Background technology]

[0002] Resin compositions containing polypropylene-based resins (polypropylene-based resin compositions) have been known as one type of resin material. Polypropylene-based resins are inexpensive and have excellent mechanical properties, moldability, solvent resistance, and appearance, making them widely used in a wide range of fields, including automotive, electrical and electronic applications, and packaging. Depending on the application, various fillers may be added to polypropylene-based resin compositions to improve performance and functionality. For example, polypropylene-based resins containing inorganic fillers are used in applications requiring rigidity and heat resistance, and in recent years, there has been a demand for even higher rigidity and heat resistance. Adding a filler that can act as a crystallization nucleating agent to polypropylene-based resins increases the degree of crystallization of the polypropylene-based resin, resulting in various advantages, such as a shorter molding cycle, improved heat resistance, and improved modulus of elasticity (rigidity). However, fillers are often in powder form, and powder-like fillers generally have a low bulk density and poor powder fluidity, making it difficult to feed high-concentration fillers into a melt-kneading device such as an extruder with precision and at a high supply rate, which can lead to the problem of making it difficult to produce a resin composition with a sufficiently high filler particle concentration with stable composition precision and at a high discharge rate. Summary of the Invention [Problem to be solved by the invention]

[0003] The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a polypropylene-based resin composition that can contain a filler at a high concentration, has high rigidity, and is excellent in heat resistance. [Means for solving the problem]

[0004] The polypropylene-based resin composition of the present invention is a polypropylene-based resin composition comprising a polypropylene-based resin, a filler, and a filler dispersant and / or a filler binder, and the content of the filler in the polypropylene-based resin composition is 20% by weight to 70% by weight. In one embodiment, the filler dispersing agent is at least one selected from the group consisting of polyhydric alcohol fatty acid esters, fatty acid amides, polyglycerin fatty acid esters, condensed hydroxy fatty acids, and alcohol esters of condensed hydroxy fatty acids. In one embodiment, the filler binder is at least one selected from the group consisting of polyolefin-based resins, polyvinyl alcohol-based resins, polyalkylene glycol-based resins, polyvinylpyrrolidone-based resins, polyester-based resins, polyamide-based resins, acrylic-based resins, urethane-based resins, and epoxy-based resins. In one embodiment, the filler binder is a polyolefin resin. In one embodiment, the total content of the filler dispersant and the filler binder in the polypropylene resin composition is 0.1% by weight to 10% by weight. In one embodiment, the polypropylene resin composition contains talc and / or mica as the filler. In one embodiment, the polypropylene resin composition has a flexural modulus at 23°C of 3,000 MPa or more. In one embodiment, the polypropylene resin composition has a deflection temperature under load of 110° C. or higher. According to another aspect of the present invention, there is provided a method for producing the polypropylene-based resin composition, which comprises melt-kneading the polypropylene-based resin and a filler granule, the filler granule containing the filler and the filler dispersant and / or filler binder, and the filler content in the filler granule is 80 to 99.9 parts by weight per 100 parts by weight of the filler granule. According to yet another aspect of the present invention, there is provided an injection-molded article formed from the above polypropylene-based resin composition. According to yet another aspect of the present invention, there is provided an extrusion molded article formed from the above polypropylene resin composition. According to yet another aspect of the present invention, there is provided a sheet-like shaped article formed from the polypropylene resin composition. [Effects of the Invention]

[0005] According to the present invention, it is possible to provide a polypropylene resin composition which can contain a filler at a high concentration, has high rigidity, and is excellent in heat resistance. DETAILED DESCRIPTION OF THE INVENTION

[0006] A. Polypropylene resin composition A-1. Overview of polypropylene resin compositions The polypropylene resin composition of the present invention contains a polypropylene resin, a filler, and a filler dispersant and / or a filler binder. The content of the filler in the polypropylene resin composition is 20% by weight to 70% by weight. The "filler content," as well as the content of each component in the "polypropylene resin content," "filler dispersant content," and "filler binder content" described below, are each weight percentages based on the total solid content in the polypropylene resin composition.

[0007] The polypropylene resin composition of the present invention can contain a high concentration of filler, which allows the polypropylene resin to crystallize quickly, and by using this resin composition, molded articles with excellent heat resistance can be obtained. Furthermore, the polypropylene resin composition can preferably possess the properties inherent to the polypropylene resin, and can form molded articles with excellent mechanical properties, such as rigidity. Furthermore, by including a filler together with a filler dispersant and / or a filler binder, the effects of adding the filler can be imparted more effectively than before.

[0008] In one embodiment, the filler and filler dispersant and / or filler binder are added in the form of filler granules. In this embodiment, a filler granule containing the filler and filler dispersant and / or filler binder is formed, and then the filler granules are mixed with a polypropylene-based resin (e.g., by melt-kneading), thereby obtaining the polypropylene-based resin. By employing such a production method, the workability of filler addition (feed characteristics (supply amount and stability)) and filler dispersibility are significantly improved, making it possible to incorporate a high filler content with good productivity.

[0009] The deflection temperature under load of the polypropylene resin composition is preferably 110°C or higher, more preferably 110°C to 150°C, and even more preferably 120°C to 140°C. The deflection temperature under load of the polypropylene resin composition is measured using a predetermined sample formed using the polypropylene resin composition. The method for measuring the deflection temperature under load will be described later.

[0010] The Charpy impact strength of the polypropylene resin composition at 23°C is preferably 1.0 kJ / m 2 More preferably, 1.5 kJ / m 2 More preferably, it is 2.0 kJ / m or more. 2 The higher the Charpy impact strength, the better, but the upper limit is, for example, 60.0 kJ / m 2 The Charpy impact strength can vary depending on the amount of filler added. The Charpy impact strength of the polypropylene resin composition at 23°C is measured using a predetermined sample formed using the polypropylene resin composition. The method for measuring the Charpy impact strength will be described later.

[0011] The flexural modulus of the polypropylene resin composition at 23°C is preferably 3,000 MPa or more, more preferably 3,500 MPa or more, and even more preferably 4,000 MPa or more. The higher the flexural modulus, the better, but the upper limit is, for example, 10,000 MPa. The flexural modulus of the polypropylene resin composition at 23°C is measured using a predetermined sample formed using the polypropylene resin composition. The method for measuring the flexural modulus will be described later.

[0012] The flexural strength of the polypropylene resin composition at 23°C is preferably 25 MPa or more, more preferably 30 MPa or more, and even more preferably 35 MPa or more. The higher the flexural strength, the better, but the upper limit is, for example, 150 MPa. The flexural strength of the polypropylene resin composition at 23°C is measured using a predetermined sample formed using the polypropylene resin composition. The method for measuring the flexural strength will be described later.

[0013] A-2. Polypropylene resin Examples of polypropylene-based resins include propylene homopolymers and copolymers of propylene and other monomers copolymerizable with propylene, with propylene homopolymers being preferred.

[0014] Examples of other monomers copolymerizable with propylene include ethylene, 1-butene, isobutene, 1-pentene, 2-methyl-1-butene, 3-methyl-1-butene, 1-hexene, 3-methyl-1-pentene, 4-methyl-1-pentene, 1-heptene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-icosene, etc. The content of propylene-derived structural units in the polypropylene resin is preferably 50 mol% or more, more preferably 80 mol% or more, more preferably 90 mol% or more, and even more preferably 95 mol% or more.

[0015] The melt flow rate of the polypropylene resin at 230°C and 2.16 kgf is preferably 0.1 g / 10 min to 100 g / min, more preferably 0.5 g / 10 min to 80 g / min, and even more preferably 1 g / 10 min to 50 g / min. Within these ranges, a polypropylene resin composition having particularly excellent moldability can be obtained. The melt flow rate is measured in accordance with JIS K7210.

[0016] The weight-average molecular weight of the polypropylene resin is preferably 50,000 to 1,000,000, more preferably 100,000 to 600,000, and even more preferably 120,000 to 500,000. Within this range, a polypropylene resin composition having particularly excellent moldability can be obtained. The weight-average molecular weight is measured by GPC (gel permeation chromatography).

[0017] The content of the polypropylene resin in the polypropylene resin composition is preferably 30 to 80% by weight, more preferably 40 to 70% by weight, and even more preferably 50 to 70% by weight. Within this range, the effect of adding the filler (e.g., crystallization-promoting effect) is preferably exhibited, and a polypropylene resin composition can be obtained in which the properties inherent to the polypropylene resin can be preferably exhibited.

[0018] The polypropylene resin may contain a polypropylene resin capable of binding fillers, such as homopolypropylene (h-PP), block polypropylene (b-PP), random polypropylene (r-PP), polypropylene copolymer, and modified polypropylene (e.g., modified with maleic anhydride, acrylic acid, etc.).

[0019] A-3. Filler As the filler, any appropriate filler can be used depending on the properties required for the polypropylene resin composition and / or the molded article obtained from the polypropylene resin composition. Only one type of filler may be used, or two or more types may be used in combination.

[0020] Preferably, talc and / or mica is used as the filler. These fillers can function favorably as crystallization nucleating agents for polypropylene-based resin compositions. In the present invention, talc and / or mica can be contained in high concentrations, which is advantageous in that the crystallization rate of the polypropylene-based resin is increased.

[0021] Talc and mica have a layered structure and weak interlayer bonding strength, making them prone to peeling. Fine particles are often used as compounding agents for plastics, improving heat resistance, dimensional stability, etc. The impurity content varies depending on the source, but those made from high-quality ores with few impurities are preferred, and it is preferable for the total amount of metal impurities, such as aluminum oxide and iron oxide, to be less than 1%.

[0022] The number average particle size of the filler can be any appropriate particle size. The number average particle size of the filler is preferably 1 μm to 40 μm, more preferably 2 μm to 10 μm, and even more preferably 3 μm to 8 μm. The size of the filler can be determined by laser diffraction.

[0023] As described above, the content of the filler in the polypropylene resin composition is 20% by weight to 70% by weight. The content of the filler in the polypropylene resin composition is preferably 30% by weight to 65% by weight, and more preferably 30% by weight to 60% by weight. Within this range, the effects of the present invention become significant.

[0024] A-4. Filler binder The filler binder can have the function of binding fillers together. Furthermore, the use of the filler binder can improve the dispersibility of the filler. Furthermore, when the filler is added in the form of a filler granule, the filler binder is used for the purpose of obtaining a granule having an appropriate bulk density and disintegration strength. Furthermore, by selecting a suitable filler binder, the productivity of the filler granule can be improved.

[0025] Resins are preferably used as the filler binder, and water-soluble or water-dispersible resins are particularly preferred. However, polysaccharides, clay minerals, and the like can also be used. Examples of filler binders include polymer binders such as polyolefin resins, polyvinyl alcohol resins, polyalkylene glycol resins, polyvinylpyrrolidone resins, polyester resins, polyamide resins, acrylic resins, urethane resins, and epoxy resins; water-soluble polysaccharides; and swelling clay minerals such as smectite and vermiculite. These may be used alone or in combination of two or more. In this specification, the term "filler binder" as used herein does not include polypropylene resins.

[0026] In one embodiment, the filler binder is preferably at least one selected from the group consisting of polyolefin-based resins, polyvinyl alcohol-based resins, polyalkylene glycol-based resins, polyvinylpyrrolidone-based resins, polyester-based resins, polyamide-based resins, acrylic-based resins, urethane-based resins, and epoxy-based resins. Among these, polyolefin-based resins are preferred. As the polyolefin-based resin, polyethylene-based resins are preferably used.

[0027] Specific examples of the polyethylene resin used as a filler binder include high-density polyethylene (HDPE), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), polyolefin elastomers (POE), polyolefin copolymers (e.g., ethylene-butene, ethylene-octene, etc.), modified polyolefins (e.g., modified products of maleic anhydride, acrylic acid, etc.), and functional polyolefin copolymers including polyolefin-based ionomers.

[0028] Commercially available filler binders may be used. Examples of commercially available binders include Chemipearl (registered trademark) manufactured by Mitsui Chemicals, Inc., HYPOD (registered trademark) manufactured by Dow Chemical Company, AQUACER (registered trademark) manufactured by BYK Japan, ZAIKXEN, SEPOLJON, and SEPOLEX (registered trademark) manufactured by Sumitomo Seika Chemicals, Michem (registered trademark) manufactured by Michelman Japan, Bondic (registered trademark) manufactured by DIC Corporation, and Saivinol and Saiden Glue (registered trademark) manufactured by Saiden Chemical Industries, Ltd. Other preferred examples include ethylene-vinyl alcohol copolymer (EVOH; EVAL (registered trademark) manufactured by Kuraray Co., Ltd.) and butenediol-vinyl alcohol copolymer (BVOH; Nichigo G-Polymer (registered trademark) manufactured by Mitsubishi Chemical Corporation). Other preferred examples include aqueous sulfopolyester dispersions sold under the trademark Eastman AQ® by Eastman Chemical Company, and the salt of hexane-1,6-diamine and adipic acid (AH salt) sold by Ascend Performance, which is diluted with water to form an aqueous polymer dispersion.

[0029] The content of the filler binder in the polypropylene resin composition is preferably 0.1 to 10% by weight, more preferably 1 to 8% by weight, and even more preferably 1 to 5% by weight.

[0030] A-5. Filler dispersant As described above, in one embodiment, the filler and filler dispersant and / or filler binder may be added in the form of filler granules. By including a filler dispersant, the effect of adding a filler can be effectively imparted. A surfactant is preferably used as the filler dispersant. The hydrophilic / hydrophobic balance of the filler dispersant (surfactant) can be controlled by adjusting the degree of esterification of the compound that becomes the filler dispersant, the type of fatty acid (presence or absence of a hydroxyl group, saturated or unsaturated fatty acid, alkyl chain length), and the degree of polymerization. The filler dispersant acts as a surfactant, thereby enhancing the dispersibility of the filler.

[0031] Examples of the filler dispersant include fatty acids, fatty acid metal salts, fatty acid sulfonates, fatty acid amides, acrylamides, polyhydric alcohol fatty acid esters, polyglycerin fatty acid esters, etc. One type of filler dispersant may be used alone, or two or more types may be used in combination.

[0032] In one embodiment, the filler dispersing agent is at least one selected from the group consisting of polyhydric alcohol fatty acid esters, fatty acid amides, polyglycerin fatty acid esters, condensed hydroxy fatty acids, and alcohol esters of condensed hydroxy fatty acids.

[0033] The polyhydric alcohol fatty acid ester is an ester compound composed of a polyhydric alcohol and a fatty acid. Examples of the polyhydric alcohol fatty acid ester include esters of polyhydric alcohols such as pentaerythritol and glycerin with fatty acids having 8 or more carbon atoms (preferably 8 to 24 carbon atoms, more preferably 10 to 22 carbon atoms).

[0034] The fatty acid amide is a compound having a structure formed by dehydration condensation of a fatty acid with ammonia or a primary or secondary amine. Examples of the fatty acid amide include saturated fatty acid monoamides such as lauric acid amide, palmitic acid amide, stearic acid amide, and behenic acid amide.

[0035] The polyglycerol fatty acid ester is an ester compound composed of polyglycerol and a fatty acid, and examples of the polyglycerol fatty acid ester include diglycerol palmitate, diglycerol stearate, diglycerol oleate, decaglycerol palmitate, decaglycerol stearate, and decaglycerol oleate.

[0036] The content of the filler dispersant in the polypropylene resin composition is preferably 0.1 to 10% by weight, more preferably 1 to 8% by weight, and even more preferably 1 to 5% by weight. Within this range, the effect of adding the filler (e.g., crystallization-promoting effect) is preferably exhibited, and a polypropylene resin composition can be obtained that can preferably exhibit the properties inherent to the polypropylene resin.

[0037] The total content of the filler dispersant and filler binder in the polypropylene resin composition is preferably 0.1% by weight to 10% by weight, more preferably 1% by weight to 8% by weight, and even more preferably 1% by weight to 5% by weight. Within this range, a polypropylene resin composition can be obtained in which the effects of the added filler (e.g., crystallization-promoting effect) are favorably exhibited and the properties inherent to the polypropylene resin are favorably exhibited. Note that the "total content of the filler dispersant and filler binder" refers to the content of the filler binder when the polypropylene resin composition does not contain a filler dispersant, and refers to the content of the filler dispersant when the polypropylene resin composition does not contain a filler binder.

[0038] A-6. Other ingredients The polypropylene resin composition may further contain any other appropriate components (additives) as needed, such as antioxidants, light stabilizers, foaming agents, ultraviolet absorbers, antiblocking agents, heat stabilizers, impact modifiers, compatibilizers, plasticizers, tackifiers, processing aids, coupling agents, flame retardants, oxygen scavengers, colorants, lubricants, release agents, antistatic agents, antifogging agents, flow improvers, and antibacterial agents.

[0039] B. Method for producing polypropylene resin composition The polypropylene-based resin composition can be produced by any appropriate method. In one embodiment, the polypropylene-based resin composition can be obtained by melt-kneading a polypropylene-based resin, a filler, and a filler dispersant and / or a filler binder. Preferably, the polypropylene-based resin composition can be obtained by melt-kneading the polypropylene-based resin and a filler granule (a granule containing the filler, the filler dispersant and / or the filler binder). Any appropriate method can be used for melt-kneading. For example, a kneader, a Banbury mixer, a roll, or a single-screw or multi-screw extruder having two or more screws can be used. Preferably, a twin-screw extruder is used. The melt-kneaded composition can be pelletized.

[0040] In one embodiment, the polypropylene-based resin composition is obtained by melt-kneading the filler granules containing the filler and a filler dispersant and / or filler binder with the polypropylene-based resin. This production method significantly improves the workability of filler addition and filler dispersion, enabling a high filler content. More specifically, the filler granules exhibit excellent stability when introduced into an extruder or other device, eliminating feed necks. Therefore, the use of the filler granules can dramatically improve the productivity of polypropylene-based resin compositions (compound processing rate per hour; discharge rate (unit: kg / Hr)). Furthermore, the use of the filler granules improves filler dispersion and molding processability (fluidity), allowing the polypropylene-based resin composition obtained using the filler granules to contain the filler at a high concentration and with high dispersion. As a result, a polypropylene-based resin composition can be obtained that effectively utilizes the effects of filler addition (e.g., crystallization-promoting effects).

[0041] (Filler granules) The filler granules can be produced by any appropriate method. The filler granules can be obtained, for example, by subjecting a mixture containing the filler, the filler dispersant, and / or the filler binder to a semi-wet granulation method. More preferably, the filler granules can be obtained by subjecting a mixture containing the filler, the filler dispersant, and the filler binder to a semi-wet granulation method. The filler, filler dispersant, and filler binder described in Section A can be used. The filler binder can function as a binder.

[0042] The content of the filler in the filler granules is preferably 80 to 99.9 parts by weight, more preferably 82 to 99 parts by weight, even more preferably 85 to 98 parts by weight, particularly preferably 87 to 97 parts by weight, and most preferably 90 to 96 parts by weight, relative to 100 parts by weight of the total solid content of the filler granules.

[0043] In one embodiment, the filler binder is mixed in the form of an aqueous solution or dispersion containing the filler binder.

[0044] In one embodiment, the method for producing the filler granules includes a mixing step of mixing the filler, the filler binder, and the filler dispersant, a granulation step of granulating the mixture obtained through the mixing step to obtain a granule precursor, and a drying step of drying the granule precursor.

[0045] In the mixing step, water may be further mixed in. The water to be added is not particularly limited, and examples thereof include tap water, distilled water, ion-exchanged water, hard water, and soft water.

[0046] The amount of water mixed is usually 1 to 30 parts by weight, preferably 3 to 25 parts by weight, and more preferably 5 to 20 parts by weight, relative to 100 parts by weight of the filler in the filler granules.

[0047] In the mixing step, the components are preferably blended at room temperature and homogenized using any suitable mixer, such as a Henschel mixer, a powder kneader (KDH, KDA, CKD, CPM) (Dalton), a Spartan mixer (SPM) (Dalton), or an SP granulator (SPG) (Dalton).

[0048] The mixing time in the mixing step can be any appropriate time depending on the type of components, the type of mixer, the component blending ratio, etc. The mixing time in the mixing step is set so that each component is uniformly dispersed. A high-speed mixer such as a Henschel mixer or a Spartan mixer can be used for processing in 1 to 10 minutes. On the other hand, a powder kneader may require processing times of several minutes to 60 minutes.

[0049] In the granulation step, a compression granulation method is preferably used. Also, in the granulation step, a semi-wet granulation method can be preferably used. Examples of the compression granulation method / semi-wet granulation method include a disk pelleting method, a tableting method, and a briquetting method. From the viewpoint of the balance between productivity and the quality of the resulting filler granules, the disc pelletizer method is preferably employed.

[0050] The basic structure of a disc pelletizer includes one or two discs with numerous 2-30 mm holes and a roller for pressure-feeding raw materials through the holes in the disc. The raw materials supplied between the disc and roller, or between two discs, are forced into the holes in the disc as the roller rotates, forming a cylindrical extrudate. The disc holes are tapered, and compressive stress is applied from the outer periphery of the die hole as the filler mixture passes through the holes. The length of this tapered hole is called the effective length. The extruded granule precursor is cut by a cutter or the like on the back surface of the disc to obtain pellet-shaped filler granules. The length of the granule precursor (and thus the filler granules) can be adjusted by adjusting the distance between the back surface of the disc and the cutter and the rotation speed of the roller. The distance between the back surface of the disc and the cutter can be any appropriate value depending on the type of filler, and is typically in the range of 1 mm to 30 mm.

[0051] More specifically, disc pelleting methods include roller-disc die methods, roller-ring die methods, double die methods, flat die methods, etc. Commercially available disc pelleting machines include the Disc Pelletter F Series manufactured by Dalton.

[0052] Any suitable drying method can be used in the drying step. After the drying step, a filler granule from which fine powder has been removed can be obtained using a vibrating sieve or the like. Any suitable drying equipment can be used in the drying step. For example, a vibrating fluidized bed dryer is preferred because it can dry efficiently in a short time, and examples of such equipment include the VDF series vibrating fluidized bed dryers manufactured by Dalton.

[0053] Various molded articles are produced using the polypropylene resin composition. For example, injection molded articles, extrusion molded articles, sheets, etc. can be produced. Furthermore, shaped articles (vacuum molded articles, press molded articles, sheet-like shaped articles, etc.) can be obtained from the sheets. Methods for molding molded articles from polypropylene resin compositions include, for example, injection molding, injection compression molding, profile extrusion molding, foam molding, ram extrusion molding, solidification extrusion, pipe molding, tube molding, heterogeneous molded article coating molding, injection blow molding, direct blow molding, T-die sheet or film molding, stretch molding, inflation molding, calendar molding, press molding, rotational molding, vacuum molding, pressure molding, melt spinning, etc. [Example]

[0054] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. Parts and percentages are by weight unless otherwise specified.

[0055] [Production Example 1] Production of filler granules A powder kneader (Dalton, trade name "KDHJ-10"; processing capacity: 6 L) was charged with 100 parts by weight of filler (talc, Asada Flour Milling Co., Ltd., trade name "JM300"; bulk density: 0.17, average particle size: 4.7 μm; "B-1" in the table) and a filler binder (polyolefin dispersion (aqueous PE dispersion); Mitsui Chemicals, Inc., trade name "Chemipearl A100"; polyolefin solids concentration: 40 wt %; polyolefin particle density: 0.89 g / cm). 318 parts by weight (solids: 7.2 parts by weight) of polyolefin particles with an average particle size of 4 μm (referred to as "D-1" in the table) and 3.75 parts by weight of a filler dispersant (polyglycerin condensed hydroxy fatty acid ester, manufactured by Taiyo Kagaku Co., Ltd., trade name "Chirabazole H818" (referred to as "C-1" in the table) were added, and the mixture was stirred for 6 minutes at 30 rpm, yielding mixture A. This mixture A was charged into a disc pelleter (manufactured by Dalton, product name "Disc Pelleter F-5 / 11-175") to obtain a pellet-like talc granule precursor. The obtained granule precursor was dried at 140°C for 4 hours using a hot air circulation dryer to obtain filler granule MB-1.

[0056] [Production Example 2] Production of filler granules Filler granules MB-2 were obtained in the same manner as in Production Example 1, except that the filler binder "D-1" was changed to 21 parts by weight (solid content: 3.1 parts by weight) of a 15 wt% aqueous solution of butenediol-vinyl alcohol copolymer (BVOH; manufactured by Mitsubishi Chemical Corporation, product name "Nichigo G Polymer AZF8035Q"; "D-2" in the table).

[0057] <Evaluation> The filler granules obtained in Production Examples 1 and 2 were subjected to the following evaluations. The results are shown in Table 1. In Table 1, the weight parts of the filler, filler dispersant, and filler binder are calculated from the charge composition of each component, and are shown as parts when the total amount of these solid contents is 100 weight parts. (1) Moisture content The amount of moisture remaining in the filler granules was measured using an infrared moisture meter FD-660 (manufactured by Kett Electric Laboratory) (unit: weight %). (2) Collapse strength measurement The disintegration stress of the dried filler granules was measured using a Kiya hardness tester WFP1600-B (manufactured by Shiro Sangyo Co., Ltd.). The measured value was the average value of 25 filler granules (unit: kg). (3) Bulk density The dried filler granules were allowed to fall naturally into a 1-liter measure, filled to the brim, and weighed to an exact volume of 1 liter, and the bulk density of the filler granules was calculated by measuring the weight (unit: kg / L).

[0058] [Table 1]

[0059] [Example 1] 70 parts by weight of homopolypropylene resin (manufactured by Japan Polypropylene Corporation, product name Novatec MA1B; in the table, "A-1") and 30 parts by weight of the above filler granules (MB-1) were added all at once from the hopper of a twin-screw extruder (manufactured by Toshiba Machine Co., Ltd., product name "TEM37SS", cylinder setting temperature: 190°C) and continuously melt-kneaded to obtain pellets of a polypropylene resin composition.

[0060] [Examples 2 to 4, Comparative Example 2] Pellets of a polypropylene resin composition were obtained in the same manner as in Example 1, except that the polypropylene resin and filler granules shown in Table 2 were used in the amounts shown in Table 2. Details of each component are as shown in Table 3.

[0061] [Comparative Example 1] Pellets of homopolypropylene resin A-1 (manufactured by Japan Polypropylene Corporation, trade name Novatec MA1B) were prepared.

[0062] Comparative Example 3 Pellets of block polypropylene resin A-2 (manufactured by Japan Polypropylene Corporation, trade name Novatec BC2E) were prepared.

[0063] Comparative Example 4 Pellets of a polypropylene resin composition were obtained in the same manner as in Example 1, except that 30 parts by weight of powdered talc (B-1) was added instead of 30 parts by weight of the filler granules.

[0064] Comparative Example 5 Pellets of a polypropylene resin composition were obtained in the same manner as in Comparative Example 4, except that the blending amount of the polypropylene resin was 50 parts by weight and the blending amount of the powdered talc (B-1) was 50 parts by weight.

[0065] [Table 2]

[0066] [Table 3]

[0067] <Evaluation> The polypropylene resin compositions obtained in the examples and comparative examples were subjected to the following evaluations, and the results are shown in Table 4. The test pieces used in the load deflection measurement, bending measurement, and Charpy impact strength measurement were prepared by molding a polypropylene resin composition at a molding temperature of 200°C using an injection molding machine (manufactured by Toyo Machinery & Metal Co., Ltd., trade name "SI-80IV-D150B" 200t) to obtain test pieces conforming to JIS K 7141. The obtained test pieces were conditioned in a constant temperature and humidity chamber for 24 hours to obtain evaluation sample A. (1) MFR Measurement was carried out using a melt indexer (manufactured by Takara Kogyo Co., Ltd.) based on JIS K7210 (230°C, 2.16 kg load conditions). (2) Deflection temperature under load (DTUL) The evaluation sample A was measured using an HDT Tester 6M-2 (manufactured by Toyo Seiki Seisakusho Co., Ltd.) under JIS K7191 (load 0.45 MPa, temperature rise rate 2°C / min) starting from a temperature of 30°C (unit: °C). (3) Bending strength The above evaluation sample A was measured using a STROGRAPH VG20-E (manufactured by Toyo Seiki Seisakusho Co., Ltd.) in accordance with JIS K7171. The measurement temperature was 23°C (unit: MPa). (4) Flexural modulus The above evaluation sample A was measured using a STROGRAPH VG20-E (manufactured by Toyo Seiki Seisakusho Co., Ltd.) in accordance with JIS K7171. The measurement temperature was 23°C (unit: MPa). (5) Charpy impact strength The above evaluation sample A was measured in accordance with JIS K7111 using a DIGITAL IMPACT TESTER DG-CB (manufactured by Toyo Seiki Seisakusho Co., Ltd.). The measurement temperature was 23°C. In preparing the test specimen for the Charpy impact test, the notch tip radius (R) was 0.25 mm. The hammer capacity was 2 J (unit: kJ / m 2 )

[0068] [Table 4]

[0069] As is clear from Table 4, the present invention can provide a resin composition containing a high concentration of filler, and by using this resin composition, a molded article having excellent mechanical properties and heat resistance can be formed.

[0070] <Processability evaluation> For the formulations of Examples 1 and 2 and Comparative Examples 4 and 5, the screw rotation speed of a twin-screw extruder (manufactured by Toshiba Machine Co., Ltd., product name "TEM37SS", cylinder set temperature: 190°C) was fixed at 100 rpm, and the material input rate was gradually increased to measure the compound processing rate per hour; the upper limit of the discharge rate. Table 5 shows the discharge rates at which pellets could be stably produced.

[0071] [Table 5]

[0072] As shown in Table 5, in Examples 1 and 2, the discharge rate was the value shown in Table 5 due to the upper limit of the load on the extruder. On the other hand, in Comparative Examples 4 and 5, the filler did not penetrate into the hopper of the twin-screw extruder, causing a hopper bridge, so the discharge rate could not be increased. As is clear from this, according to the present invention, resin compositions containing a high concentration of filler can be efficiently produced.

Claims

1. A polypropylene-based resin composition comprising a polypropylene-based resin, a filler, and a filler binder, the filler and the filler binder are in the form of filler granules, the filler binder is a water-dispersible polyethylene resin, The content of the filler in the polypropylene resin composition is 20% by weight to 70% by weight. Polypropylene-based resin composition.

2. further comprising a filler dispersant; 2. The polypropylene resin composition according to claim 1, wherein the filler dispersing agent is at least one selected from the group consisting of polyhydric alcohol fatty acid esters, fatty acid amides, polyglycerin fatty acid esters, condensed hydroxy fatty acids, and alcohol esters of condensed hydroxy fatty acids.

3. 3. The polypropylene resin composition according to claim 2, wherein the total content of the filler dispersant and the filler binder in the polypropylene resin composition is 0.1% by weight to 10% by weight.

4. The polypropylene resin composition according to claim 1 , wherein the filler comprises talc and / or mica.

5. 5. The polypropylene resin composition according to claim 1, which has a flexural modulus at 23°C of 3,000 MPa or more.

6. The polypropylene resin composition according to any one of claims 1 to 5, which has a deflection temperature under load of 110°C or higher.

7. A method for producing a polypropylene-based resin composition, comprising melt-kneading the polypropylene-based resin and a filler granule, The filler granules contain the filler and the filler binder, The content of the filler in the filler granules is 80 parts by weight to 99.9 parts by weight based on 100 parts by weight of the filler granules. A method for producing the polypropylene resin composition according to any one of claims 1 to 6.

8. An injection-molded article formed from the polypropylene resin composition according to any one of claims 1 to 6.

9. An extrusion molded article formed from the polypropylene resin composition according to any one of claims 1 to 6.

10. A sheet-like shaped product formed from the polypropylene resin composition according to any one of claims 1 to 6.

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