Filler granules

Abstract

To provide a filler granulated substance which can improve supply stability and supply accuracy of a filler when a resin composition is prepared, and can stably obtain a resin composition with high productivity.SOLUTION: There is provided a filler granulated substance for improving supply stability and supply accuracy of a filler when a resin composition is prepared, and stably obtaining a resin composition with high productivity. The filler granulated substance is particularly preferably usable when a resin composition containing a biodegradable resin is obtained, and can efficiently provide a resin composition to which filler-derived characteristics are imparted without inhibiting biodegradable resin-derived characteristics.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a filler granule. [Background technology]

[0002] In recent years, biodegradable resins have attracted attention from an environmental perspective. Resin compositions containing biodegradable resins may be enhanced by adding fillers. Fillers are often powders. However, powdered fillers generally have low bulk densities and poor flowability during transport. This poses numerous handling challenges, including transportation, storage, packaging, and stable supply to processing machines, as well as issues to be resolved regarding the working environment and human safety. Furthermore, powdered fillers are prone to feed necks at the inlet when fed into equipment (e.g., extruders), and the output rate is low, making it difficult to stably produce resin compositions with high filler concentrations at high production rates. Patent Document 1 discloses a method for preparing a resin composition by forming pulverized cellulose fibers into a fiber molded product using a water-soluble thermoplastic polymer and melt-kneading the fiber molded product into a thermoplastic resin. However, the resin composition described here is characterized by the presence or absence of agglomerates with a fiber diameter of 1 mm or more, making it difficult to achieve satisfactory filler dispersibility. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-105203 Summary of the Invention [Problem to be solved by the invention]

[0004] The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a filler granule that can improve the stability and accuracy of filler supply when preparing a resin composition, and enables a resin composition to be obtained stably with high productivity. [Means for solving the problem]

[0005] The filler granules of the present invention contain a filler, a binder, and a dispersant, wherein the bulk density of the filler is 0.01 kg / L to 1 kg / L, the binder contains a water-soluble polymer, and the filler content is 80 parts by weight to 99.9 parts by weight relative to 100 parts by weight of the total amount of the filler, the binder, and the dispersant. In one embodiment, the filler is in powder form. In one embodiment, the water-soluble polymer is at least one selected from the group consisting of polyvinyl alcohol-based polymers, polyalkylene oxide-based polymers, polyacrylic acid-based polymers, partially neutralized polyacrylic acids, crosslinked polyacrylic acid-based polymers, polyvinylpyrrolidone-based polymers, polyacrylamide-based polymers, polyvinylamide-based polymers, polyamine-based polymers, water-soluble polyamide-based polymers, water-soluble polyester-based polymers, water-soluble cellulose, and polysaccharides. In one embodiment, the dispersant 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 content of the dispersant is 0.1 parts by weight to 15 parts by weight relative to 100 parts by weight of the total amount of the filler, the binder, and the dispersant. According to another aspect of the present invention, there is provided a method for producing the filler granules, which includes a mixing step of mixing the filler, the binder, and the 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. In one embodiment, the above-mentioned production method comprises granulation by a semi-wet granulation method in the above-mentioned granulation step. In one embodiment, the above-mentioned production method includes carrying out granulation by a disc pelleter method in the granulation step. According to yet another aspect of the present invention, there is provided use of the above-mentioned filler granules as a raw material for melt-kneading with a biodegradable resin. In one embodiment, the biodegradable resin is at least one selected from the group consisting of aliphatic polyester resins, aliphatic-aromatic polyester resins, polyvinyl alcohol resins, and natural rubber. [Effects of the Invention]

[0006] According to the present invention, it is possible to provide a filler granule that can improve the stability and accuracy of filler supply when preparing a resin composition, and that enables a resin composition to be obtained stably with high productivity. The filler granule of the present invention can be particularly preferably used when obtaining a resin composition containing a biodegradable resin, and a resin composition can be provided to which the properties inherent to the filler are efficiently imparted without impairing the properties inherent to the biodegradable resin. DETAILED DESCRIPTION OF THE INVENTION

[0007] A. Overview of filler granules The filler granules of the present invention contain a filler, a binder, and a dispersant. The filler has a bulk density of 0.01 kg / L to 1 kg / L. Typically, the filler is in a powder form. The binder contains a water-soluble polymer. The content of the filler is 80 parts by weight to 99.9 parts by weight relative to 100 parts by weight of the total amount of the filler, binder, and dispersant.

[0008] The filler granules of the present invention are used in the production of filler-containing resin compositions and can be added during melt-kneading of the resin composition. In this way, the use of the filler granules of the present invention can produce filler-containing resin compositions with filler-derived functionality. The filler granules of the present invention are configured such that the filler is granulated with a binder. Using the filler granules to prepare the filler-containing resin composition can improve the composition stability and productivity of the resin composition. Specifically, the filler granules have excellent stability when introduced into equipment such as extruders. Therefore, using the filler granules can dramatically improve the composition accuracy (composition stability) and productivity (compound processing rate per hour) of the filler-containing resin composition. Furthermore, the use of the filler granules can significantly reduce dust-related pollution in the work environment, improve the occupational safety and health environment for workers, and significantly reduce the time required for cleaning equipment between equipment changes. Furthermore, by adding a dispersant, it is possible to obtain a filler granule that can be produced with excellent production efficiency despite containing a large amount of filler and that has excellent quality stability (shape stability, uniformity of pellet hardness, low fine powder contamination).Although the filler granule containing a dispersant contains a high concentration of filler, a filler-containing resin composition obtained using the filler granule has excellent filler dispersibility.

[0009] In one embodiment, the filler-containing resin composition contains a biodegradable resin (hereinafter, a filler-containing resin composition containing a biodegradable resin may also be referred to as a filler-containing biodegradable resin composition). Because the filler granules of the present invention contain a water-soluble polymer as a binder, the use of the filler granules can enhance the affinity between the filler and the biodegradable resin. Therefore, by using the filler granules in combination with a biodegradable resin, a filler-containing biodegradable resin composition with significantly excellent filler dispersibility, even at a high filler content, can be obtained with high compositional precision and high productivity. The water-soluble polymer disappears over time as the biodegradable resin decomposes, which is advantageous in terms of environmental impact.

[0010] In one embodiment, the filler granules are produced by a semi-wet granulation method, which makes the above-mentioned effects more pronounced.

[0011] The filler granules may have any suitable shape, typically cylindrical (pellet-like).

[0012] When the filler granules are cylindrical, the diameter of the filler granules is, for example, 2 mm to 5 mm. The length (height) of the filler granules is, for example, 1 mm to 7 mm. Such a shape makes it possible to obtain a filler granule that can be preferably combined with a resin (particularly a biodegradable resin). The diameter of the filler granules can be adjusted by the diameter of the die hole in the disc plate during granulation, and the length can be adjusted by the distance between the disc plate and the cutter. By adjusting the filler granules to match the pellet size of the resin (particularly a biodegradable resin) to be combined with them, handling properties are improved, and the filler dispersibility in the molten compound is also improved.

[0013] The breaking stress of the filler granules measured with a Kiya hardness tester is preferably 0.05 kg to 10 kg, more preferably 0.5 kg to 7 kg, and even more preferably 1 kg to 5 kg. Within these ranges, handling properties and filler dispersibility are excellent. Here, the breaking stress refers to the average disintegration stress measured for 20 granules (preferably 25 granules) or more.

[0014] The moisture content of the filler granules may be any appropriate amount, preferably 25% by weight or less, more preferably 10% by weight or less, even more preferably 5% by weight or less, still more preferably 3% by weight or less, particularly preferably 1% by weight or less, and most preferably 0.5% by weight or less.

[0015] The bulk density of the filler granules can be any appropriate value depending on the type of filler. When the filler is a mineral (natural mineral), the bulk density of the filler granules is preferably 0.5 kg / L to 2.0 kg / L. Increasing the bulk density increases the supply rate and supply stability of the filler granules when melt-kneading with a resin (particularly a biodegradable resin).

[0016] A-1. Filler As described above, the bulk density of the filler is 0.01 kg / L to 1 kg / L. The bulk density of the filler is preferably 0.1 kg / L to 0.8 kg / L, and more preferably 0.2 kg / L to 0.6 kg / L. The bulk density of the filler is calculated by allowing the filler to fall naturally into a measuring container until the container is filled to the brim, weighing out a volume of exactly 1 liter, and measuring the weight (unit: kg / L). As described above, in one embodiment, the filler is in a powder form. The filler granules of the present invention are advantageous in that they can improve the supply stability and supply accuracy of fillers (particularly powdery fillers with low bulk density), making it possible to stably obtain filler-containing resin compositions with high productivity. The size of the filler can be any appropriate size. The number-average particle diameter of the filler is, for example, 10 nm to 100 μm. The size of the filler can be determined by laser diffraction.

[0017] As described above, the content of the filler is 80 to 99.9 parts by weight relative to 100 parts by weight of the total amount of the filler, binder, and dispersant. Within this range, a filler-containing resin composition can be obtained to which the properties derived from the filler are efficiently imparted. The content of the filler is preferably 82 to 99 parts by weight, more preferably 85 to 98 parts by weight, even more preferably 87 to 97 parts by weight, and even more preferably 90 to 96 parts by weight relative to 100 parts by weight of the total amount of the filler, binder, and dispersant. In one embodiment, the content of the filler is 90 to 99.9 parts by weight relative to 100 parts by weight of the filler granules.

[0018] The volume content of the filler in the filler granules is preferably 40% to 95% by volume, more preferably 50% to 90% by volume, and even more preferably 60% to 85% by volume.

[0019] As the filler, any appropriate filler can be used depending on the properties required for the filler-containing resin composition and / or the molded article obtained from the filler-containing resin composition.

[0020] Examples of properties and effects that can be imparted by the above fillers include weight increase or weight reduction, reinforcement (increased rigidity, increased elastic modulus, increased strength), dimensional stability, molding cycle (crystallization rate), crystallinity, thermal conductivity, electrical conductivity, magnetism, piezoelectricity, vibration damping, sound insulation, sliding properties, heat insulation, electromagnetic wave absorption, light reflectivity, light scattering, heat radiation, flame retardancy, radiation protection, ultraviolet protection, moisture removal, dehydration, deodorization, gas absorption, gas barrier, anti-blocking, oil absorption, antibacterial properties, promotion of biodegradation, and increased bio-content (increased proportion of naturally derived components).

[0021] For example, calcium carbonate, talc, silica, and clay are suitable for weight increase. For reinforcement, wollastonite, potassium titanate, xonotlite, gypsum fiber, aluminum borate, fibrous magnesium compound (MOS), aramid fiber, various fiber systems, carbon fiber, glass fiber, talc, mica, glass flakes, polyoxybenzoyl whiskers, and the like are suitable. For antibacterial properties, catechin, silver ion-supported zeolite, copper phthalocyanine, and the like are suitable. For gas barrier properties, synthetic mica, clay-synthetic mica nanofillers, and the like are suitable. For weight reduction, balloon systems such as silica balloons, glass balloons, cenospheres, perlite, and shirasu balloons are suitable. For conductivity, carbon black, graphite, carbon fiber, metal powder, metal fiber, and metal foil are suitable. For the purpose of imparting magnetism, various magnetic materials, various ferrites, magnetic iron oxide, samarium-cobalt (Sm-Co), Nd-Fe-B, etc. are suitable. For the purpose of imparting thermal conductivity, alumina, AlN, BN, BeO, etc. are suitable. For the purpose of imparting piezoelectricity, barium titanate, lead zirconate titanate (PZT), etc. are suitable. For the purpose of imparting vibration damping properties, mica, graphite, potassium titanate, xonotlite, carbon fiber, ferrite, etc. are suitable. For the purpose of imparting sound insulation properties, iron powder, lead powder, barium sulfate, etc. are suitable. For the purpose of imparting sliding properties, graphite, hexagonal BN, molybdenum sulfide, Teflon (registered trademark) powder, talc, high molecular weight polyethylene, etc. are suitable. For the purpose of imparting electromagnetic wave absorption, electromagnetic wave absorbing ferrite, graphite, charcoal powder, carbon microcoil (CMC), carbon nanotubes (CNT), PZT, etc. are suitable. For the purpose of imparting light reflection and light scattering, titanium oxide, glass beads, calcium carbonate, aluminum powder, mica, etc. are suitable. For the purpose of imparting heat radiation, magnesium oxide, hydrotalcite, MOS, alumina, charcoal powder, etc. are suitable. For the purpose of flame retardancy, antimony oxide, aluminum hydroxide, magnesium hydroxide, zinc borate, red phosphorus, zinc carbonate, hydrotalcite, dawsonite, bromine-based flame retardants, phosphorus-based flame retardants, etc. are suitable. For the purpose of radiation protection, lead powder, barium sulfate, etc. are suitable.For the purpose of "ultraviolet protection," titanium oxide, zinc oxide, iron oxide, etc. are preferred. For the purpose of dehumidification and dehydration, calcium oxide, magnesium oxide, etc. are preferred. For the purpose of deodorization and gas absorption, zeolite, activated clay, etc. are preferred. For the purpose of anti-blocking (preventing film from being pressed together), silica, calcium carbonate, talc, spherical microparticles (silicone or acrylic beads), etc. are preferred. For the purpose of oil absorption (printing ink absorption, quick drying, etc.), algae-like calcium carbonate, algae-like xonotlite, etc. are preferred. For the purpose of water absorption, water-absorbing polymer gels, calcium oxide, magnesium oxide, etc. are preferred. For the purpose of increasing the bio-content, cellulosic materials (wood flour, wood fiber, sawdust, wood chips, newsprint, paper, flax, hemp, straw, rice husks, kenaf, jute, sisal, peanut shells, soybean husks, etc.), starch, natural rubber, etc. are suitable.

[0022] A-2. Binder As described above, the binder includes a water-soluble polymer. The binder is used to bind the powder filler together to obtain a granulated product having an appropriate disintegration stress. In one embodiment, the binder may be a single water-soluble polymer or a combination of multiple water-soluble polymers. Examples of water-soluble polymers include polyvinyl alcohol (PVA)-based polymers, polyalkylene oxide-based polymers (e.g., polyethylene oxide (PEO)), polyacrylic acid-based polymers, partially neutralized polyacrylic acids (e.g., low-molecular-weight sodium polyacrylate, high-molecular-weight sodium polyacrylate), crosslinked polyacrylic acid-based polymers, polyvinylpyrrolidone (PVP)-based polymers, polyacrylamide-based polymers, polyvinylamide-based polymers, polyamine-based polymers, water-soluble polyamide-based polymers, water-soluble polyester-based polymers, water-soluble celluloses (e.g., hydroxyethyl methyl cellulose (HEMC), hydroxypropyl methyl cellulose (HPMC), methyl cellulose (MC), hydroxyethyl cellulose (HEC), carboxymethyl cellulose (CMC), hydroxypropyl cellulose (HPC)), polysaccharides (e.g., proteins, starches, dextrins, pullulans, etc.), etc. One type of water-soluble polymer may be used alone, or two or more types may be used in combination. In this specification, water solubility (that is, the property of being soluble in water) means that 10% by weight or more can be dissolved in water at 25°C.

[0023] The content of the water-soluble polymer in the binder is preferably 80 parts by weight or more, more preferably 90 parts by weight or more, even more preferably 95 parts by weight or more, and particularly preferably 100 parts by weight, per 100 parts by weight of the binder.

[0024] In one embodiment, filler granules are produced using a polymer liquid (polymer solution, polymer dispersion) containing a binder. The polymer liquid can efficiently and uniformly coat the filler surface, resulting in filler granules with little powder fall-off, high collapse hardness, and high bulk density. Furthermore, the dispersibility of the filler in the filler-containing resin composition can be significantly improved.

[0025] Commercially available binders (or polymer solutions containing binders) may be used. Examples of commercially available binders include ethylene-vinyl alcohol copolymers (EVOH; EVAL® manufactured by Kuraray Co., Ltd.), butenediol-vinyl alcohol copolymers (BVOH; Nichigo G-Polymer® manufactured by Mitsubishi Chemical Corporation), polyvinylpyrrolidone (K Series; manufactured by Nippon Shokubai Co., Ltd.), AQ Nylon® (water-soluble polyamide) manufactured by Toray Industries, Inc., Eastman AQ® (aqueous sulfopolyester dispersion) manufactured by Eastman Chemical Co., Ltd., a 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, PLASCOAT® (water-soluble polyester) manufactured by GOO Chemical Co., Ltd., and SAIDEN GLUE® (dextrin-based adhesive) manufactured by Saiden Chemical Co., Ltd.

[0026] The content of the binder can be any appropriate proportion depending on the size, shape, water absorption, oil absorption, bulk density, etc. of the filler. The content of the binder is preferably 0.1 to 20 parts by weight, preferably 0.5 to 18 parts by weight, more preferably 1 to 18 parts by weight, and even more preferably 3 to 15 parts by weight, relative to 100 parts by weight of the total amount of the filler, binder, and dispersant. Within this range, the binding force between the fillers is preferably exerted, and a filler granule with excellent handleability can be obtained.

[0027] A-3. Dispersants A surfactant is preferably used as the dispersant. The hydrophilic / hydrophobic balance of the dispersant (surfactant) can be controlled by adjusting the degree of esterification of the dispersant compound, the type of fatty acid (presence or absence of hydroxyl groups, saturated or unsaturated fatty acid, alkyl chain length), and the degree of polymerization. The use of a dispersant can improve the productivity (discharge rate) of the filler granules and also improve the cleanability of the processing machine.

[0028] Furthermore, when a filler-containing resin composition is produced by melt-kneading a resin composition using filler granules containing a dispersant, the surfactant action of the dispersant can enhance filler dispersibility.

[0029] Examples of the 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 dispersant may be used alone, or two or more types may be used in combination.

[0030] In one embodiment, the dispersant 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.

[0031] 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).

[0032] 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.

[0033] 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.

[0034] The polyglycerol fatty acid ester, condensed hydroxy fatty acid, and alcohol ester of condensed hydroxy fatty acid may be commercially available products. Examples of commercially available products include "Tirabazole P-4," "Tirabazole VR-01," and "Tirabazole VR-08" (polyglycerol fatty acid ester), and "Tirabazole H-818" (alcohol ester of condensed hydroxy fatty acid), manufactured by Taiyo Kagaku Co., Ltd. These may be used alone or in combination of two or more.

[0035] The content of the dispersant is preferably 0.1 to 15 parts by weight, more preferably 1 to 10 parts by weight, and even more preferably 1 to 5 parts by weight, relative to 100 parts by weight of the total amount of the filler, binder, and dispersant.

[0036] A-4. Other ingredients The filler granules may further contain any other appropriate components (additives) as needed. Examples of additives include antioxidants, light stabilizers, foaming agents, UV absorbers, antiblocking agents, heat stabilizers, impact modifiers, antibacterial agents, compatibilizers, plasticizers, tackifiers, processing aids, lubricants, coupling agents, flame retardants, oxygen scavengers, and colorants. The additives may be added in the form of liquid, powder, pellets, granules, or masterbatch during filler granulation or in the resin compounding process. In one embodiment, the additives may be blended into a polymer liquid, granulated in a semi-wet granulator, and then added to the filler granules.

[0037] B. Manufacturing method of filler granules The filler granules can be produced by any appropriate method, for example, by subjecting a mixture containing the filler, the binder, and the dispersant to a semi-wet granulation method.

[0038] In one embodiment, the method for producing the filler granules includes a mixing step of mixing a filler, a binder, and a 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. In one embodiment, the binder is added in the mixing step as an aqueous liquid (aqueous solution or aqueous dispersion) containing the binder. In another embodiment, a dispersant is further added in the mixing step.

[0039] When the aqueous liquid containing a binder is an aqueous solution (homogeneous system), the content of the binder in the aqueous liquid (aqueous solution) containing a binder is preferably 1 to 70 parts by weight, more preferably 3 to 50 parts by weight, and even more preferably 5 to 30 parts by weight, relative to 100 parts by weight of the aqueous liquid. Within such a range, a filler granule in which the fillers are preferably bound together can be stably obtained.

[0040] When the aqueous liquid containing a binder is an aqueous dispersion (heterogeneous system), the solids concentration of the binder in the aqueous liquid containing a binder (aqueous dispersion) is preferably 1% by weight to 70% by weight, more preferably 3% by weight to 60% by weight, and even more preferably 5% by weight to 50% by weight. Within these ranges, the viscosity can be favorably adjusted when mixing the aqueous liquid and the filler, and a mixed liquid with excellent dispersibility of the binder can be obtained. By using such a mixed liquid, a filler granule in which the fillers are favorably bound together can be stably obtained.

[0041] The mixing ratio of the aqueous liquid containing the binder is preferably 1 to 70 parts by weight, more preferably 5 to 50 parts by weight, and even more preferably 10 to 30 parts by weight, per 100 parts by weight of the filler.

[0042] In the mixing step, other components (e.g., the additives described above), a solvent (preferably water), etc. may be further mixed. In one embodiment, the addition of these components optimizes the mixing of the aqueous liquid containing the binder, the powdered thermoplastic polymer, and the filler. 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.

[0043] 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).

[0044] 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. Preferably, the mixing time is set so that the surface of the filler is sufficiently and uniformly coated with the binder. 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 in several minutes to 60 minutes.

[0045] In the granulation step, a compression granulation method is preferably used. In addition, 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 a balance between productivity and the quality of the obtained filler granules, the disk pelleting method is preferably used.

[0046] 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 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 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 is typically in the range of 1 mm to 30 mm, preferably 5 mm to 20 mm, and more preferably 5 mm to 10 mm.

[0047] 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.

[0048] Any suitable drying method can be used in the drying step. After the drying step, the filler granules can be treated with a vibrating sieve or the like to remove fine powder. 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.

[0049] C. Melt compounding of resin and filler granules In one embodiment, the filler granules are used as a raw material for melt-kneading with a biodegradable resin. That is, in one embodiment, a melt compound of the filler granules and a biodegradable resin is provided. The biodegradable resin is not particularly limited, and examples thereof include aliphatic polyester resins (e.g., homopolymers or copolymers of polycaprolactone, polylactic acid, polyethylene succinate, polybutylene succinate adipate, polyhydroxyvalerate, etc., or modified homopolymers or copolymers thereof), aliphatic-aromatic polyester resins (e.g., block polymers or random polymers of aliphatic carboxylic acids or hydroxy acids, aromatic dicarboxylic acids, and 1,3-propanediol, etc.), and polyvinyl alcohol resins (e.g., polyvinyl alcohol, polyvinyl acetate, polyvinyl butyrate, ethylene-vinyl alcohol copolymers, etc.). Natural rubber may also be used. The above resins may be used alone or in combination of two or more. Any suitable method can be used to produce the molten compound. 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. A twin-screw extruder is preferably used. The melt-kneaded composition is pelletized. [Example]

[0050] 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.

[0051] [Example 1] 22 parts by weight of a binder solution (15% aqueous solution of polyvinyl alcohol; Kuraray Co., Ltd., product name "PVA103"; saponification degree 98% or higher; in the table, "B-1") and 3.75 parts by weight of a dispersant (polyglycerol condensed hydroxy fatty acid ester; Taiyo Kagaku Co., Ltd., product name "Chirabazole H818"; in the table, "C-1") were added to a 1 L plastic container and stirred at room temperature for 20 minutes using a stirring blade to obtain Mixture A. Next, 100 parts by weight of a filler (mica; Chuzhou Grea Minerals Co., product name "GM-4"; average particle size: 18 μm; in the table, "A-1") was added to a powder kneader (Dalton Co., product name "KDHJ-10"; processing capacity: 6 L), and Mixture A was added to the powder kneader while stirring with the stirring blade at a rotation speed of 30 rpm. Mixture B was then obtained by stirring for 6 minutes. Mixture B was placed in a disc pelleter (Dalton, product name "Disc Pelleter F-5 / 11-175") to obtain a pellet-shaped granulated precursor. The die hole diameter was 3 mm, the die plate thickness was 15 mm, the effective length of the die hole was 10 mm, and the roller rotation speed of the dispelleter was 108 rpm. The obtained granule precursor was dried at 140°C for 4 hours using a hot air circulation dryer to obtain filler granule MB-1.

[0052] [Examples 2 to 4] Filler granules MB-2 to MB-4 were obtained in the same manner as in Example 1, except that the filler, binder, and dispersant shown in Table 1 were used in the amounts shown in Table 1. Note that, for Example 3, no drying treatment was performed.

[0053] [Comparative Example 1] An attempt was made to granulate a mixture obtained by blending 100 parts by weight of filler (GM-4) with 20 parts by weight of tap water without adding a binder solution or dispersant, but the mixture had no binding strength and easily disintegrated, making it impossible to obtain granules.

[0054] The specific details of each component used in Examples 1 to 4 and Comparative Example 1 are as shown in Table 2.

[0055] [Table 1]

[0056] [Table 2]

[0057] <Evaluation> The filler granules obtained in Examples 1 to 4 and Comparative Example 1 were subjected to the following evaluations. The results are shown in Table 3. (1) Granulation properties The obtained filler granules were checked, and the granulation properties were evaluated according to the following criteria. Good: Granules with a diameter of 3 mm are obtained. △: The filler is in the form of granules, but the binding force is insufficient and it easily falls apart. ×: The filler clogs the die, or the filler has no cohesiveness and does not form granules. (2) Granulation speed The production rate of the filler granules per hour (kg / Hr) was calculated. (3) Bulk density The dried filler granules were allowed to fall naturally into a 1-liter measure, filled to the brim, and weighed to a volume of exactly 1 liter, and the bulk density (unit: kg / L) of the filler granules was calculated by measuring the weight. (4) Pellet size Twenty particles of the filler granules were taken out, and the length and diameter of the particles were measured using a vernier caliper, and the average values ​​were calculated. (5) Moisture content The amount of moisture (unit: weight %) remaining in the filler granules was measured using an infrared moisture meter (FD-660 manufactured by Kett Electric Laboratory). (6) Collapse strength measurement The disintegration stress (unit: kg) of the dried filler granules was measured using a Kiya hardness tester (manufactured by Shiro Sangyo Co., Ltd., product name "WPF1600-B") The measured value was the average value of 25 filler granules. (7) Filler concentration 1 to 3 g of filler granules were collected and placed in a crucible in an electric furnace at 600°C for 3 hours to remove the binder components, and the filler concentration in the filler granules was calculated from the weight change (unit: wt%). For MB-3 (Example 3), the calculation was based on the charged composition and water content.

[0058] [Table 3]

[0059] As shown in Table 3, MB-1 to MB-4 enable the production of filler pellets with stable pellet shape, high granulation speed, and appropriate hardness.

[0060] [Example 5] 67 parts by weight of biodegradable resin (polylactic acid (PLA); manufactured by NatureWorks, Inc., trade name "Ingeo 4032D"; melting point 155-170°C) and 33 parts by weight of filler granules (MB-2) were charged into a twin-screw extruder (manufactured by Toshiba Machine Co., Ltd., trade name "TEM37SS", L / D = 48) and continuously melt-kneaded to produce pellets of the resin composition. The PLA resin and the filler granules were each independently quantitatively fed into a twin-screw extruder via a gravimetric feeder at the hopper position at the most upstream part of the extruder. The cylinder temperatures of the extruder were set to 150°C in the front section, 200°C in the middle section, and 200°C in the rear section. The screw rotation speed was 100 rpm, and the discharge rate was 20 kg / Hr. The melt-kneaded resin composition was extruded in the form of strands, cooled in a water-cooled bath, and formed into pellets approximately 3 mm in length.

[0061] [Example 6] Pellets of a resin composition were obtained in the same manner as in Example 5, except that the blending amounts of the biodegradable resin and the granulated filler were as shown in Table 4.

[0062] [Example 7] Sixty parts by weight of a biodegradable resin (polybutylene adipate terephthalate (PBAT), manufactured by BASF, trade name "Ecoflex F Blend C1200", MFR: 3.8 g / 10 min) and 40 parts by weight of the filler granules (MB-3) were charged into a twin-screw extruder (manufactured by Toshiba Machine Co., Ltd., trade name "TEM37SS", L / D = 48) and continuously melt-mixed to produce pellets of the resin composition. The filler granules (MB-3) had a moisture content of 18 wt% and were used as is. The moisture contained in the filler granules (MB-3) acts as a plasticizer for starch in the temperature range of 70 to 90°C. An open vent was provided at the top of the barrel in the midstream section of the extruder to allow open devolatilization, and two more vents were provided at two locations at the top of the barrel in the downstream section to allow devolatilization under reduced pressure of -90 kPa. The cylinder temperatures of the extruder were set to 100°C in the front section, 180°C in the middle section, and 180°C in the rear section. The screw rotation speed was 120 rpm, and the discharge rate was 20 kg / Hr. The melt-kneaded resin composition was extruded in the form of strands, cooled in a water-cooled bath, and formed into pellets approximately 3 mm in length.

[0063] Comparative Example 2 Pellets of the resin composition were obtained in the same manner as in Example 5, except that 50 parts by weight of talc powder (A-2) was used instead of 50 parts by weight of filler granules (MB-2), and the amount of biodegradable resin (polylactic acid (PLA)) was 50 parts by weight. In Comparative Example 2, the talc powder (A-2) formed bridges in the hopper for supplying raw materials to the extruder, causing poor engagement with the extruder screw and making stable production impossible. Comparing Example 5 with Comparative Example 2, it can be seen that the use of filler granules (MB-2) eliminates the feed neck of the talc powder (A-2), dramatically improves productivity, and at the same time enables the production of a melt compound that satisfies the good dispersibility of the filler in the resin.

[0064] <Evaluation> The pellets of the resin compositions obtained in Examples 5 to 7 and Comparative Example 2 were subjected to the following evaluations. The results are shown in Table 4. (a) Dispersibility of filler in resin composition The resin composition pellets were rolled in a hot press to form a sheet with a thickness of about 0.5 mm. The sheet was visually inspected for any remaining filler aggregates and evaluated according to the following criteria. AA: Good dispersion state with almost no filler agglomerates observed A: A state in which a small amount of relatively small filler aggregates remain BB: A state in which a considerable number of relatively small filler aggregates remain B: Large filler aggregates (Distribution ranking: AA>A>BB>B (Left good)) (b) Granulation properties of resin composition pellets ○: Stable continuous granulation is possible ×: Continuous production not possible

[0065] [Table 4]

[0066] As is clear from Table 4, according to the present invention, it is possible to obtain a resin composition having excellent filler dispersibility for a thermoplastic resin, particularly a biodegradable resin.

Claims

1. Use of a filler granule as a raw material for melt-kneading with a biodegradable resin, The filler granules are Contains a filler, a binder, and a dispersant, The bulk density of the filler is 0.01 kg / L to 1 kg / L, the binder comprises a water-soluble polymer; the content of the filler is 80 parts by weight to 99.9 parts by weight relative to 100 parts by weight of the total amount of the filler, the binder, and the dispersant; the water-soluble polymer is at least one selected from the group consisting of polyvinyl alcohol-based polymers, polyalkylene oxide-based polymers, polyacrylic acid-based polymers, partially neutralized polyacrylic acids, crosslinked polyacrylic acid-based polymers, polyvinylpyrrolidone-based polymers, polyacrylamide-based polymers, polyvinylamide-based polymers, polyamine-based polymers, water-soluble polyamide-based polymers, water-soluble polyester-based polymers, water-soluble cellulose, and polysaccharides; the dispersant 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; The filler granules have a breaking stress of 1 kg to 5 kg as measured by a Kiya hardness tester. Use of filler granulations.

2. 2. The use of the filler granulation according to claim 1, wherein the filler is in powder form.

3. 3. Use of the filler granules according to claim 1 or 2, wherein the dispersant 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.

4. Use of the filler granules according to any one of claims 1 to 3, wherein the content ratio of the dispersant is 0.1 parts by weight to 15 parts by weight per 100 parts by weight of the total amount of the filler, the binder, and the dispersant.

5. Use of the filler granules according to any one of claims 1 to 4, wherein the biodegradable resin is at least one selected from the group consisting of aliphatic polyester resins, aliphatic / aromatic polyester resins, polyvinyl alcohol resins, and natural rubber.

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