WO2022249652A1 - Resin composition and molded article - Google Patents

Resin composition and molded article Download PDF

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Publication number
WO2022249652A1
WO2022249652A1 PCT/JP2022/011223 JP2022011223W WO2022249652A1 WO 2022249652 A1 WO2022249652 A1 WO 2022249652A1 JP 2022011223 W JP2022011223 W JP 2022011223W WO 2022249652 A1 WO2022249652 A1 WO 2022249652A1
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Prior art keywords
calcium carbonate
resin composition
resin
mass
phosphate
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PCT/JP2022/011223
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French (fr)
Japanese (ja)
Inventor
剛紀 笹川
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株式会社Tbm
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Publication of WO2022249652A1 publication Critical patent/WO2022249652A1/en

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
    • B65D85/00—Containers, packaging elements or packages, specially adapted for particular articles or materials
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00—Use of inorganic substances as compounding ingredients
    • C08K3/18—Oxygen-containing compounds, e.g. metal carbonyls
    • C08K3/24—Acids; Salts thereof
    • C08K3/26—Carbonates; Bicarbonates
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K5/00—Use of organic ingredients
    • C08K5/49—Phosphorus-containing compounds
    • C08K5/51—Phosphorus bound to oxygen
    • C08K5/52—Phosphorus bound to oxygen only
    • C08K5/521—Esters of phosphoric acids, e.g. of H3PO4
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K5/00—Use of organic ingredients
    • C08K5/49—Phosphorus-containing compounds
    • C08K5/51—Phosphorus bound to oxygen
    • C08K5/52—Phosphorus bound to oxygen only
    • C08K5/524—Esters of phosphorous acids, e.g. of H3PO3
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K9/00—Use of pretreated ingredients
    • C08K9/04—Ingredients treated with organic substances
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L101/00—Compositions of unspecified macromolecular compounds
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers

Definitions

  • the present invention relates to resin compositions and molded articles. More specifically, in the present invention, although the thermoplastic resin is highly filled with calcium carbonate, the amount of elution under acidic conditions is small, the moldability is good, and physical properties such as mechanical strength are excellent.
  • the present invention relates to resin compositions and molded articles made of such resin compositions, particularly food packaging containers and tableware.
  • the inorganic substance powder falls off during use, and the inorganic substance powder falls off into the food, especially liquid food such as strongly acidic beverages. It has been a problem that there is a risk that calcium carbonate used as a elution.
  • a resin container used for food with a pH of 5 or less is required to have a small amount of elution in warm acetic acid, but a resin composition containing a large amount of calcium carbonate tends to have a large amount of elution.
  • Patent Literature 2 discloses a sheet-like laminate in which outer layers of a thermoplastic resin are laminated on both sides of an inner layer containing more than 50% by mass of an inorganic filler.
  • Patent Document 2 also describes a technique of treating the surface of calcium carbonate particles with a silane coupling agent or a metallic soap.
  • the surface treatment technique itself is known, and for example, non-patent document 1, patent documents 3 and 4 describe calcium carbonate surface-treated with resin acid, silane, phosphate ester, etc., in addition to fatty acid.
  • a laminate such as that described in Patent Document 2 requires a lamination process during manufacturing, which poses a problem in terms of productivity. Since it is also difficult to provide a surface layer on the edge of a container or the like, good evaluation results may not be obtained in the acetic acid elution test. The cost of the resin laminate tends to be high, and it is difficult to contribute to environmental protection by reducing the consumption of synthetic resin. A technique for suppressing elution from an inorganic substance powder-filled resin composition without laminating a resin layer is desired.
  • Patent Document 2 also states that surface treatment with calcium stearate or the like can suppress the formation of voids at the interface between the calcium carbonate particles and the thermoplastic resin, and improve the moldability of the laminate. However, as shown in the examples below, if the surface treatment agent is inappropriately selected, the moldability and mechanical properties of the resin composition may rather deteriorate.
  • Non-Patent Document 1 Many of the conventional surface treatment methods, such as Non-Patent Document 1, have been studied in systems with a smaller amount of calcium carbonate compounded compared to thermoplastic resins and the like.
  • US Pat. No. 5,400,005 polymer compositions containing up to 95% by weight of surface-treated inorganic substances are also described.
  • Patent Document 4 describes an electric wire sheath layer based on a composition filled with a large amount of silane-treated calcium carbonate or the like, its physical properties such as mechanical strength are not evaluated.
  • resin compositions filled with a large amount of inorganic substance powder, especially resin compositions for food the relationship between the surface treatment method and the moldability and mechanical properties has not been studied at present. .
  • An object of the present invention is to provide a resin composition which is excellent in physical properties such as physical strength and particularly suitable for food packaging containers and tableware, and a molded article made of such a resin composition.
  • a surface treatment agent containing a phosphate ester particularly a surface treatment agent mainly composed of a phosphate ester having a specific structure, is used to produce carbonic acid.
  • the inventors have found that by treating the surface of calcium, the moldability can be improved without deteriorating the physical properties of the resin composition, and the amount of elution into acetic acid and the like can be reduced, leading to the present invention.
  • the present invention for solving the above problems is a resin composition containing a thermoplastic resin and an inorganic substance powder at a mass ratio of 50:50 to 10:90, wherein the inorganic substance powder contains a phosphate ester.
  • a resin composition characterized by being calcium carbonate surface-treated with a surface-treating agent.
  • the phosphate is polyoxyethylene lauryl ether phosphate.
  • the average particle diameter of the calcium carbonate particles calculated from the measurement results of the specific surface area by an air permeation method according to JIS M-8511 is 0.7 ⁇ m or more and 6.0 ⁇ m or less. A resin composition is shown.
  • the calcium carbonate is ground calcium carbonate.
  • the thermoplastic resin is a polyolefin resin.
  • the polyolefin-based resin is a resin composition comprising a polyethylene-based resin and/or a polypropylene-based resin.
  • a food packaging container made of any one of the resin compositions described above is shown.
  • the resin composition has a small amount of elution under acidic conditions, good moldability, and excellent physical properties such as mechanical strength, even though the thermoplastic resin is highly filled with calcium carbonate. goods are provided. Molded articles based on the resin composition of the present invention are particularly suitable for food packaging containers and tableware.
  • the resin composition of the present invention contains a thermoplastic resin and calcium carbonate surface-treated with a surface-treating agent containing a phosphate ester in a mass ratio of 50:50 to 10:90. These components in the resin composition are described below.
  • thermoplastic resin In the resin composition of the present invention, the type of thermoplastic resin is not particularly limited. Examples include polyethylene resins, polypropylene resins, polymethyl-1-pentene, polyolefin resins such as ethylene-cyclic olefin copolymers; ethylene-vinyl acetate copolymers, ethylene-acrylic acid copolymers, ethylene-methacrylic acid Copolymer, metal salt of ethylene-(meth)acrylic acid copolymer (ionomer), ethylene-alkyl acrylate copolymer, ethylene-alkyl methacrylate copolymer, maleic acid-modified polyethylene, maleic acid-modified polypropylene functional group-containing polyolefin resins such as; nylon-6, nylon-6,6, nylon-6,10, nylon-6,12 and other polyamide resins; polyethylene terephthalate and its copolymers, polyethylene naphthalate, polybutylene Aromatic polyester resins such as
  • thermoplastic resins can also be used in combination. It also contains elastomer components such as styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-butadiene-ethylene copolymer, styrene-isoprene-ethylene copolymer, acrylonitrile-butadiene copolymer, fluorine-based elastomer, etc. It's okay to be
  • thermoplastic resins polyolefin resins are preferred in terms of moldability, performance, and economy.
  • the polyolefin-based resin is a polyolefin-based resin having olefin component units as a main component. Cyclic olefin copolymers and the like, and mixtures of two or more thereof are also included.
  • the above-mentioned "mainly composed” means that the olefin component unit is contained in the polyolefin resin in an amount of 50% by mass or more, and the content is preferably 75% by mass or more, more preferably 85% by mass. % or more, more preferably 90 mass % or more.
  • homopolymers (homopolymers) of polyolefins are preferred.
  • the method for producing the polyolefin resin used in the present invention is not particularly limited, and can be obtained by any method using a Ziegler-Natta catalyst, a metallocene catalyst, a radical initiator such as oxygen or a peroxide, or the like. It may be something else.
  • the resin composition of the present invention preferably contains a polyethylene-based resin and/or a polypropylene-based resin as these polyolefin-based resins. More preferably, the thermoplastic resin consists essentially of polyethylene-based resin and/or polypropylene-based resin. These resins are particularly excellent in the balance of physical properties, moldability, and cost, and are suitable as the thermoplastic resin component in the resin composition of the present invention. In particular, polypropylene-based resins are preferably used because they are particularly excellent in the balance between mechanical strength and heat resistance.
  • polypropylene-based resin examples include resins having a propylene component unit of 50% by mass or more, such as propylene homopolymers and copolymers of propylene and other copolymerizable monomers.
  • Propylene homopolymers include isotactic, syndiotactic, atactic, hemiisotactic, and linear or branched polypropylenes exhibiting various stereoregularities.
  • the above copolymer may be a random copolymer or a block copolymer, and may be a terpolymer as well as a binary copolymer.
  • Copolymerization components include ethylene, 1-butene, isobutylene, 1-pentene, 3-methyl-1-butene, 1-hexene, 3,4-dimethyl-1-butene, 1-heptene, ⁇ -olefins having 4 to 10 carbon atoms such as 3-methyl-1-hexene; furthermore, tetrafluoroethylene, vinyl acetate and the like, but are not limited thereto.
  • propylene homopolymers as a result of polymerization, there are cases where a structure as if an ⁇ -olefin such as hexene is copolymerized is partly included, but in the present invention, such a polymer is also included. , is broadly included as a propylene homopolymer (propylene homopolymer). These polypropylene-based resins can be used alone or in combination of two or more.
  • polyethylene-based resin examples include resins having an ethylene component unit of 50% by mass or more.
  • examples include high-density polyethylene (HDPE), low-density polyethylene (LDPE), medium-density polyethylene, linear low-density polyethylene ( LLDPE), ethylene-vinyl acetate copolymer, ethylene-propylene copolymer, ethylene-propylene-butene 1 copolymer, ethylene-butene 1 copolymer, ethylene-hexene 1 copolymer, ethylene-4 methylpentene 1 Copolymers, ethylene-octene 1 copolymers, etc., and mixtures of two or more thereof are also included.
  • HDPE high-density polyethylene
  • LDPE low-density polyethylene
  • LLDPE linear low-density polyethylene
  • ethylene-vinyl acetate copolymer ethylene-propylene copolymer
  • the inorganic powder contained in the resin composition of the present invention is calcium carbonate surface-treated with a surface-treating agent containing a phosphate ester.
  • Calcium carbonate includes those prepared by a synthetic method (so-called light calcium carbonate) and those obtained by mechanically pulverizing and classifying natural raw materials containing CaCO3 as a main component such as limestone (so-called heavy calcium carbonate). Any of them may be used, and these may be used in combination.
  • the shape thereof is not particularly limited, and may be in the form of particles, flakes, granules, fibers, or the like. As for the particulate form, it may be spherical as generally obtained by a synthetic method, or irregularly shaped as obtained by pulverizing collected natural minerals. .
  • the average particle size of the inorganic substance powder such as calcium carbonate described in this specification refers to a value calculated from the measurement result of the specific surface area by the air permeation method according to JIS M-8511.
  • a specific surface area measuring device SS-100 manufactured by Shimadzu Corporation can be preferably used.
  • the average particle size is larger than 6.0 ⁇ m, for example, when a sheet-like molded product is formed, the inorganic powder protrudes from the surface of the molded product and falls off, depending on the layer thickness of the molded product. Otherwise, the surface properties, mechanical strength, etc. may be impaired.
  • the particle size distribution does not contain particles having a particle size of 45 ⁇ m or more.
  • the particles are too fine, the viscosity will increase significantly when kneaded with the above-mentioned resin, which may make it difficult to produce molded articles. Such a problem can be prevented by setting the average particle size of the inorganic powder to 0.7 ⁇ m or more, particularly 0.8 ⁇ m or more and 6.0 ⁇ m or less.
  • calcium carbonate is a first calcium carbonate having an average particle size of 0.7 ⁇ m or more and less than 2.0 ⁇ m, particularly 0.8 ⁇ m or more and less than 2.0 ⁇ m, as measured by an air permeation method according to JIS M-8511; It may also contain a second calcium carbonate having an average particle size of 2.0 ⁇ m or more and 6.0 ⁇ m or less, particularly 2.0 ⁇ m or more and 5.0 ⁇ m or less, as measured by an air permeation method using M-8511. As a result, it is possible to improve the physical properties such as the surface properties of the molded product and the printability and blocking property.
  • the average particle size of the first calcium carbonate is a and the average particle size of the second calcium carbonate is b
  • the a/b ratio is 0.85 or less, more preferably. is roughly 0.10 to 0.70, more preferably 0.10 to 0.50. This is because a particularly excellent effect can be expected by jointly using particles having such a clear difference in average particle size to some extent.
  • each of the first calcium carbonate and the second calcium carbonate preferably has a coefficient of variation (Cv) of the distribution of particle diameters ( ⁇ m) of about 0.01 to 0.10, particularly 0.03. It is desirable to be about 0.08. If the variation in particle size defined by the coefficient of variation (Cv) is this level, it is considered that each powder group can provide more complementary effects.
  • the mass ratio of the first calcium carbonate to the second calcium carbonate is preferably about 90:10 to 98:2, more preferably about 92:8 to 95:5. Three or more calcium carbonate groups having different average particle size distributions may be used.
  • calcium carbonate preferably contains ground calcium carbonate.
  • the inorganic substance powder in the resin composition of the present invention is composed of heavy calcium carbonate and its unavoidable impurities.
  • heavy calcium carbonate is obtained by mechanically pulverizing and processing natural limestone or the like, and is clearly distinguished from synthetic calcium carbonate produced by chemical precipitation reaction or the like.
  • the pulverization method includes a dry method and a wet method, and the dry method is preferred.
  • ground calcium carbonate is characterized by surface irregularities and a large specific surface area due to the fact that particles are formed by a pulverization process. Since ground calcium carbonate has such an irregular shape and a large specific surface area, when blended in a thermoplastic resin, ground calcium carbonate has a larger contact interface with the thermoplastic resin. , is effective for uniform dispersion.
  • the specific surface area of the calcium carbonate is desirably about 3,000 cm 2 /g or more and 35,000 cm 2 /g or less, though it depends on the average particle size. .
  • the specific surface area referred to here is obtained by the air permeation method. When the specific surface area is within this range, there is a tendency to suppress deterioration in processability of the obtained molded article.
  • the irregularity of the calcium carbonate particles can be represented by a low degree of spheroidization of the particle shape, and is not particularly limited. 0.95 or less, more preferably 0.55 or more and 0.93 or less, and still more preferably 0.60 or more and 0.90 or less. If the circularity of the calcium carbonate particles is within this range, the strength and molding processability of the molded article will be moderate.
  • the circularity can be expressed by (the projected area of the grain)/(the area of the circle having the same circumferential length as the projected circumferential length of the grain).
  • the method for measuring the roundness is not particularly limited, and for example, the projected area and the projected peripheral length of the grain may be measured from a micrograph, or image analysis software that is generally commercially available may be used.
  • the above calcium carbonate is at least partly surface-treated with a surface-treating agent containing a phosphate ester.
  • a surface-treating agent containing a phosphate ester By such surface treatment (surface modification), the dispersibility and reactivity of calcium carbonate can be enhanced, and the physical properties and moldability of the resin composition can be improved.
  • surface treatment surface modification
  • the dispersibility and reactivity of calcium carbonate can be enhanced, and the physical properties and moldability of the resin composition can be improved.
  • unlike calcium carbonate that has been modified with general-purpose surface treatment agents such as fatty acids even when it is highly filled in a thermoplastic resin, it has excellent physical properties such as mechanical properties and elution under acidic conditions in a well-balanced manner.
  • a resin composition suitable for packaging containers and tableware is provided.
  • a surface treatment agent containing a phosphoric acid ester includes all surface treatment agents containing a phosphoric acid-based ester.
  • phosphoric acid-based esters include monoesters, diesters and triesters of phosphoric acid and alcohols; monoesters, diesters and triesters of phosphoric acid and phenols; monoesters, diesters and triesters of phosphoric acid and alkylphenols.
  • phosphoric acid esters having a structure in which an alkyloxy group, an alkyloxyalkyleneoxy group, and a hydroxy group are bonded to a phosphorus atom; and salts thereof, such as sodium salts, potassium salts, ammonium salts, etc., but are not limited thereto.
  • salts thereof such as sodium salts, potassium salts, ammonium salts, etc., but are not limited thereto.
  • a plurality of types of these phosphate esters can also be used in combination.
  • surface treatment agents containing fatty acids, resin acids, fatty acid anhydride-modified resins, etc., together with these phosphate esters may be used.
  • the phosphate ester is preferably a monoester, a diester, a salt thereof, or a mixture of two or more thereof.
  • surface treatment agents containing monoesters and diesters are effective in modifying the surface of calcium carbonate.
  • the longer the aliphatic hydrocarbon chain length the more excellent the compatibility with the thermoplastic resin tends to be, and the effect of the present invention is particularly remarkable.
  • phosphoric acid esters having long-chain aliphatic hydrocarbon groups in the molecule such as monoesters, diesters and triesters of phosphoric acid and long-chain alcohols; monoesters, diesters and triesters of phosphoric acid and long-chain alkylphenols. monoesters, diesters, triesters of phosphoric acid, long-chain alcohols and alkylene oxides; and salts thereof. More preferably, it is one or more phosphoric acid esters selected from monoesters and diesters of phosphoric acid and long-chain alcohols, monoesters and diesters of phosphoric acid, long-chain alcohols and alkylene oxide, and salts thereof. .
  • the aliphatic hydrocarbon group in the phosphate ester is not particularly limited, and includes all saturated or unsaturated linear, branched, or cyclic aliphatic hydrocarbon groups. It may be substituted with a hydroxy group, an alkoxy group, an amino group, a nitro group, a cyano group, or the like. Examples include isopropyl group, butyl group, hexyl group, n-octyl group, isooctyl group, decyl group, dodecyl group (lauryl group), pentadecyl group (myristyl group), tetradecyl group (myristyl group), hexadecyl group (palmityl group).
  • octadecyl group (stearyl group), hexadecenyl group (palmitoleyl group), octadecenyl group (oleyl group), octadecadienyl group (linoleyl group, elaidolinolenyl group), octadecatrienyl group (linolenyl group), hydroxy octadecenyl group (linoleyl group) and the like, but not limited thereto.
  • the number of carbon atoms in the aliphatic hydrocarbon group is also not particularly limited, and may be, for example, an aliphatic hydrocarbon group having 3 to 20 carbon atoms, especially 8 to 18 carbon atoms, especially 10 to 14 carbon atoms.
  • the phosphoric acid ester is particularly preferably monoester, diester and/or salt thereof of phosphoric acid, alcohol and alkylene oxide.
  • the hydrocarbon group (corresponding to C x H 2x+1 ) of the phosphate ester may have, for example, an unsaturated bond or a cyclic structure, and the number of hydrogen atoms may be 2x-1 or less.
  • the surface of calcium carbonate can be particularly effectively modified, the amount of elution under acidic conditions is small, and it is possible to obtain a resin composition having good physical properties such as mechanical strength.
  • a resin composition having good physical properties such as mechanical strength.
  • having an alkylene oxide unit in the molecule causes the aliphatic hydrocarbon group to spread more widely from the phosphate ester on the calcium carbonate surface, resulting in the surface It is considered that the compatibility between the treated calcium carbonate and the thermoplastic resin is good.
  • the number of alkylene oxide units (z in Formula 1) is also not particularly limited. For example, 1 to 12 alkylene oxide units, particularly 1 to 4 Individual ones are preferred. More preferably, polyoxyethylene (1-4) lauryl ether phosphate and/or salts thereof, particularly preferably monopolyoxyethylene (2) lauryl ether phosphate, dipolyoxyethylene (2) lauryl ether phosphate, and salts thereof.
  • ⁇ Surface treatment method> There is no particular limitation on the surface treatment method of calcium carbonate with the phosphate ester as described above, and various known surface treatment methods can be employed. For example, a method of adding a phosphoric acid ester to a slurry of calcium carbonate and stirring (wet method), a method of adding calcium carbonate and a phosphoric acid ester to a grinder or a mixer, and optionally heating and stirring (dry method), Furthermore, a method of stirring a hydrous cake of calcium carbonate and a phosphoric acid ester while heating them in a mixer may be used, but the methods are not limited to these. Depending on the type of phosphate ester used as the surface treatment agent, it is generally preferable to carry out the surface treatment of light calcium carbonate by a wet method and the surface treatment of heavy calcium carbonate by a dry method.
  • the amount ratio of phosphate ester to calcium carbonate during surface treatment is not particular limitation.
  • the amount of the phosphate ester is 0.2 to 10 parts by mass, particularly 0.5 to 5 parts by mass, more preferably about 1 to 3 parts by mass, based on 100 parts by mass of calcium carbonate.
  • the amount of phosphate on the surface of calcium carbonate can be quantified by a known analysis method such as solvent extraction or pyrolysis GC/MS.
  • the aqueous slurry has a calcium carbonate concentration of 10 to 300 g/L, particularly 25 to 200 g/L. With such a concentration, the productivity of surface treatment is enhanced, and the workability is not lowered due to an increase in viscosity.
  • the slurry temperature in the wet method is preferably 20 to 98°C, more preferably 40 to 90°C, still more preferably 60 to 80°C.
  • the surface treatment agent can be uniformly adsorbed and bonded onto the calcium carbonate, and the surface can be treated uniformly.
  • the slurry temperature is 98° C. or lower, there is no risk of bumping or the like, and a pressure-resistant device is not required.
  • the slurry may contain a surfactant.
  • the surface treatment by the dry method can be performed by kneading calcium carbonate and phosphate ester in a kneader such as a Henschel mixer, kneader, or extrusion kneader.
  • a kneader such as a Henschel mixer, kneader, or extrusion kneader.
  • a desired phosphoric acid ester can be added to the grinder, and surface treatment can be performed at the same time as adjusting the particle size of the calcium carbonate.
  • the temperature during the surface treatment can be arbitrarily set according to the type of phosphate ester used, but is generally about 20 to 150°C, particularly 40 to 130°C, and further about 60 to 120°C. is preferred. By carrying out the surface treatment at 20° C.
  • the surface treatment agent can be uniformly adsorbed and bonded onto the calcium carbonate, and the surface can be treated uniformly.
  • the treatment temperature is about 150° C. or lower, the risk of thermal deterioration and deterioration of the surface treatment agent can be reduced. More preferably, the temperature is higher than the melting point of the phosphate used. This allows the surface treatment agent to more uniformly adsorb and bind onto the calcium carbonate.
  • polyoxyethylene lauryl ether phosphate or the like is liquid at room temperature, the surface treatment can be performed at room temperature. When polyoxyethylene stearyl ether phosphate or the like is used, it may be kneaded at a temperature of about 50 to 150°C.
  • a small amount of solvent can be used in combination even in the dry method.
  • an aqueous solution of a phosphoric acid ester, particularly a salt-type phosphoric acid ester may be added to calcium carbonate and kneaded or pulverized as described above.
  • the temperature during treatment is preferably 20 to 150°C, particularly about 40 to 98°C. This makes it possible to reduce the risk of non-uniform adsorption and bumping of the surface treatment agent.
  • the inorganic substance powder is calcium carbonate surface-treated with a surface treatment agent containing a phosphate ester as described above, but may further contain inorganic substance powders other than these.
  • examples include powdery carbonates, sulfates, silicates, phosphates, borates, oxides, or hydrates thereof of calcium, magnesium, aluminum, titanium, iron, zinc, etc.
  • non-surface-treated calcium carbonate, magnesium carbonate, zinc oxide, titanium oxide, silica, alumina, clay, talc, kaolin, aluminum hydroxide, magnesium hydroxide, aluminum silicate, magnesium silicate, silicic acid Calcium, aluminum sulfate, magnesium sulfate, calcium sulfate, magnesium phosphate, barium sulfate, silica sand, carbon black, zeolite, molybdenum, diatomaceous earth, sericite, shirasu, calcium sulfite, sodium sulfate, potassium titanate, bentonite, wollastonite, Dolomite, graphite and the like can be mentioned.
  • the inorganic substance powder in the resin composition of the present invention is preferably 90% by mass or more, more preferably 95% by mass or more, and particularly preferably 95% by mass or more. is substantially entirely composed of the above-mentioned surface-treated calcium carbonate powder, excluding unavoidable impurities.
  • the resin composition of the present invention contains the thermoplastic resin and the inorganic powder in a mass ratio of 50:50 to 10:90. If the content of the inorganic substance powder is too small, it is difficult to obtain physical properties such as texture and strength of the resin composition.
  • the ratio of the inorganic substance powder to the total mass of the thermoplastic resin and the inorganic substance powder is preferably 52% by mass or more, more preferably 55% by mass or more.
  • the upper limit of the ratio is preferably 80% by mass or less, more preferably 75% by mass or less, and particularly preferably 70% by mass or less.
  • the resin composition according to the present invention may optionally contain other additives as auxiliary agents.
  • Other additives include, for example, colorants, lubricants, coupling agents, fluidity modifiers (fluidity modifiers), cross-linking agents, dispersants, antioxidants, ultraviolet absorbers, flame retardants, stabilizers, and electrifying agents. Inhibitors, foaming agents, plasticizers, etc. may be blended. These additives may be used alone or in combination of two or more. Moreover, these may be blended in the kneading step described later, or may be blended in the raw material components in advance before the kneading step.
  • the amount of these other additives added is not particularly limited as long as it does not impede the desired physical properties and processability, but the mass of the entire resin composition is 100%.
  • each of these other additives is blended in a ratio of about 0 to 10% by mass, particularly about 0.04 to 5% by mass, and the total amount of the other additives is 10% by mass or less. is desired.
  • 10 to 45% by mass, especially 20 to 25% by mass of thermoplastic resin; 90 to 45% by mass, especially 75 to 55% by mass of surface-modified calcium carbonate; 0 to 10% by weight, in particular 0.04 to 5% by weight of the above additives may be contained.
  • plasticizers include triethyl citrate, acetyl-triethyl citrate, dibutyl phthalate, diaryl phthalate, dimethyl phthalate, diethyl phthalate, di-2-methoxyethyl phthalate, dibutyl tartrate, and o-benzoylbenzoic acid. Ester, diacetin, epoxidized soybean oil and the like. These plasticizers are usually blended in an amount of about several percent by mass with respect to the thermoplastic resin, but the amount is not limited to these ranges, and depending on the application of the resin composition, epoxidized soybean oil or the like is added in an amount of about 20 to 50 parts by mass. Blending is also possible. However, in the resin composition of the present invention, the blending amount is preferably about 0.5 to 10 parts by weight, particularly about 1 to 5 parts by weight, per 100 parts by weight of the thermoplastic resin.
  • organic pigments such as azo-based, anthraquinone-based, phthalocyanine-based, quinacridone-based, isoindolinone-based, diosazine-based, perinone-based, quinophthalone-based, and perylene-based pigments, ultramarine blue, titanium oxide, titanium yellow, and iron oxide. (Rouge), chromium oxide, zinc white, carbon black and other inorganic pigments.
  • lubricants include fatty acid-based lubricants such as stearic acid, hydroxystearic acid, complex stearic acid, and oleic acid; fatty alcohol-based lubricants; stearamide, oxystearamide, oleylamide, erucylamide, ricinolamide, behenamide, and methylol.
  • Aliphatic amide-based lubricants such as amides, methylenebisstearamide, methylenebisstearobehenamide, higher fatty acid bisamic acids, complex amides; n-butyl stearate, methyl hydroxystearate, polyhydric alcohol fatty acid esters, Fatty acid ester-based lubricants such as saturated fatty acid esters and ester-based waxes; and fatty acid metal soap-based lubricants such as zinc stearate and magnesium stearate.
  • antioxidants phosphorus-based antioxidants, phenol-based antioxidants, and pentaerythritol-based antioxidants can be used.
  • Phosphorus-based antioxidants more specifically phosphorus-based antioxidants such as phosphites and phosphates, are preferably used.
  • phosphites include triphenyl phosphite, trisnonylphenyl phosphite, tris(2,4-di-t-butylphenyl) phosphite, and other phosphorous acid triesters, diesters, and monoesters. is mentioned.
  • Phosphate esters include trimethyl phosphate, triethyl phosphate, tributyl phosphate, trioctyl phosphate, triphenyl phosphate, tricresyl phosphate, tris(nonylphenyl) phosphate, 2-ethylphenyl diphenyl phosphate, and the like. These phosphorus-based antioxidants may be used alone, or two or more of them may be used in combination.
  • Phenolic antioxidants include ⁇ -tocopherol, butylhydroxytoluene, sinapyl alcohol, vitamin E, n-octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, 2- t-butyl-6-(3'-t-butyl-5'-methyl-2'-hydroxybenzyl)-4-methylphenyl acrylate, 2,6-di-t-butyl-4-(N,N-dimethyl aminomethyl)phenol, 3,5-di-t-butyl-4-hydroxybenzylphosphonate diethyl ester, and tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionyloxymethyl]methane etc., and these can be used alone or in combination of two or more.
  • the flame retardant is not particularly limited, but for example, halogen flame retardants or non-phosphorus halogen flame retardants such as phosphorus flame retardants and metal hydrates can be used.
  • halogen flame retardants include halogenated bisphenol compounds such as halogenated bisphenylalkanes, halogenated bisphenyl ethers, halogenated bisphenylthioethers, and halogenated bisphenylsulfones, brominated bisphenol A, bromine Bisphenol-bis(alkyl ether) compounds such as bisphenol S, chlorinated bisphenol A, and chlorinated bisphenol S, and phosphorus-based flame retardants such as aluminum tris(diethylphosphinate) and bisphenol A bis(diphenyl phosphate).
  • triaryl isopropyl phosphate, cresyl di-2,6-xylenyl phosphate, aromatic condensed phosphate esters, etc., and metal hydrates such as aluminum trihydrate, magnesium hydroxide, combinations thereof, etc. can be exemplified, respectively, and these can be used alone or in combination of two or more. It works as a flame retardant assistant, and can improve the flame retardant effect more effectively.
  • antimony oxides such as antimony trioxide and antimony pentoxide, zinc oxide, iron oxide, aluminum oxide, molybdenum oxide, titanium oxide, calcium oxide, magnesium oxide, etc. can be used in combination as flame retardant aids. .
  • the foaming agent is mixed or injected into the resin composition that is in a molten state in the melt kneader and undergoes a phase change from solid to gas, liquid to gas, or gas itself, and the porosity of the resin composition ( foaming ratio).
  • a foaming agent that is liquid at room temperature undergoes a phase change to a gas depending on the resin temperature and dissolves in the molten resin, while a foaming agent that is gas at room temperature does not undergo a phase change and dissolves in the molten resin as it is.
  • the foaming agent dispersed and dissolved in the molten resin expands inside the sheet as the pressure is released when the molten resin is extruded into a sheet from an extrusion die, forming a large number of fine closed cells within the sheet and foaming. A sheet is obtained.
  • the foaming agent secondarily acts as a plasticizer that lowers the melt viscosity of the raw material resin composition, and lowers the temperature for making the raw resin composition plasticized.
  • blowing agents include aliphatic hydrocarbons such as propane, butane, pentane, hexane and heptane; alicyclic hydrocarbons such as cyclobutane, cyclopentane and cyclohexane; chlorodifluoromethane, difluoromethane, trifluoromethane, trichlorofluoromethane; Methane, dichloromethane, dichlorofluoromethane, dichlorodifluoromethane, chloromethane, chloroethane, dichlorotrifluoroethane, dichloropentafluoroethane, tetrafluoroethane, difluoroethane, pentafluoroethane, trifluoroethane, dichlorotetrafluoroethane, trichlorotrifluoroethane , tetrachlorodifluoroethane and perfluorocyclobut
  • a carrier resin containing an active ingredient of the foaming agent can be preferably used.
  • carrier resins include crystalline olefin resins. Among these, crystalline polypropylene resins are preferred.
  • hydrogen carbonate etc. are mentioned as an active ingredient. Among these, hydrogen carbonate is preferred.
  • a blowing agent concentrate containing a crystalline polypropylene resin as a carrier resin and a hydrogen carbonate as a thermally decomposable blowing agent is preferred.
  • the content of the foaming agent contained in the foaming agent in the molding process can be appropriately set according to the amounts of the thermoplastic resin and the inorganic substance powder, etc., and is 0.04 to 5.0% relative to the total mass of the resin composition. 00% by mass is preferable.
  • fluidity modifiers can also be used.
  • examples include, but are not limited to, peroxides such as dialkyl peroxides such as 1,4-bis[(t-butylperoxy)isopropyl]benzene and the like.
  • these peroxides may also act as crosslinkers.
  • part of the copolymer is crosslinked by the action of the peroxide, which helps control the physical properties and workability of the thermoplastic resin composition.
  • the amount of the peroxide to be added is not particularly limited, but should be in the range of 0.04 to 2.00% by mass, particularly 0.05 to 0.50% by mass, based on the total mass of the thermoplastic resin composition. is preferred.
  • a method for preparing the resin composition of the present invention a conventional method can be used, and the method can be appropriately set according to the molding method (extrusion molding, injection molding, vacuum molding, etc.).
  • the molding method can be prepared by kneading and melting a thermoplastic resin and an inorganic powder. Melt-kneading is preferably carried out by applying a high shear stress while dispersing each component uniformly.
  • a mixing device various devices such as a general extruder, a kneader, and a Banbury mixer can be used.
  • the prepared resin composition can be made into pellets of desired shape and size, for example, and used to produce various molded articles.
  • a sheet-shaped molded article can be produced by kneading various raw materials with a twin-screw extruder and extruding a sheet-shaped material.
  • the present invention also includes a molded article made of the resin composition described above.
  • the resin composition of the present invention has good moldability and excellent physical properties such as mechanical strength even though the thermoplastic resin is highly filled with calcium carbonate. Therefore, it can be molded into molded articles of various shapes that are useful for various purposes. Also, since the resin composition of the present invention has a small amount of elution under acidic conditions, it can be used for moldings that come into direct contact with food, unlike conventional inorganic powder-filled resin compositions. Moreover, at that time, it is not necessary to form a two-layer or three-layer structure in which resin layers such as polyolefin are laminated. Therefore, the molded article of the present invention is particularly suitable for food packaging containers and tableware.
  • the present invention further includes a food packaging container comprising the above resin composition.
  • the shape and the like of the food packaging container according to the present invention are not particularly limited, and may be of various shapes and sizes, such as lunch boxes, cups, plates, bowls, bowls, spoons, forks, and chopsticks.
  • the container may have a thickness of 40 ⁇ m to 10 mm, more preferably 100 ⁇ m to 5 mm. If the wall thickness is within this range, the calcium carbonate is uniformly dispersed in the thermoplastic resin, so that good moldability and workability can be obtained, and a homogeneous and defect-free container without uneven wall thickness can be obtained. can be formed.
  • the method for producing the molded article of the present invention is not particularly limited as long as it can be molded into a desired shape, and any of conventionally known methods such as extrusion molding, injection molding, vacuum molding, blow molding and calendar molding can be used. Can be molded.
  • the resin composition of the present invention does not need to have a 2- to 3-layer structure with other resin layers when molded into a food packaging container or the like. can do.
  • the resin composition according to the present invention contains a foaming agent and a molded product in the form of a foam is obtained, as long as it can be molded into a desired shape, conventionally known foam molding methods can be used.
  • liquid phase foaming methods such as injection foaming, extrusion foaming and foam blowing, or solid phase foaming methods such as bead foaming, batch foaming, press foaming and normal pressure secondary foaming can be used.
  • solid phase foaming methods such as bead foaming, batch foaming, press foaming and normal pressure secondary foaming
  • an injection foaming method and an extrusion foaming method can be desirably used.
  • the molding temperature in injection molding, extrusion molding, etc. varies to some extent depending on the molding method and the type of thermoplastic resin used, so it cannot be defined unconditionally, but the melting point of the thermoplastic resin component is preferable.
  • the temperature can be about +5 to 100°C, particularly about +10 to 50°C, for example, 180 to 260°C, more preferably 190 to 230°C. At such a temperature, the resin composition according to the present invention has good drawdown properties and spreadability, and can be molded into a predetermined shape without locally modifying the composition.
  • Example 1 100 parts by mass of heavy calcium carbonate (Softon (trade name) 1000 manufactured by Bihoku Funka Kogyo Co., Ltd.) having an average particle size of 2.2 ⁇ m (according to the air permeation method) and a specific surface area of 10,000 cm 2 /g, is mixed with polyoxyethylene. Lauryl ether phosphate (Toho Chemical Industry Co., Ltd.
  • Example 1 The same operation as in Example 1 was performed using untreated SOFTON 1000 as the inorganic powder. Table 1 shows the test results.
  • SOFTON 1000 was dispersed in purified water (concentration 100 g/L) to prepare a slurry.
  • a sodium salt of a phosphoric acid ester having a long unsaturated aliphatic hydrocarbon chain and an ethylene oxide unit (unsaturated EO phosphoric acid ester salt, Phosphanol (registered trademark) RD-720 manufactured by Toho Chemical Industry Co., Ltd.) , Hydrocarbon chain carbon number 18, ethylene oxide unit number 7) is added to 1 L of slurry (3% by mass based on calcium carbonate), stirred at 50 ° C. for 30 minutes, filtered, dried and surface treated. Calcium carbonate was obtained. Using this surface-treated calcium carbonate, a sheet was produced in the same manner as in Example 1, and its physical properties were evaluated. Table 1 shows the test results.
  • Example 2 As the surface-treated calcium carbonate, commercially available fatty acid surface-treated heavy calcium carbonate (average particle size 2.2 ⁇ m; Ryton (registered trademark) S-4 manufactured by Bihoku Funka Kogyo Co., Ltd.) was used, and the same operation as in Example 1 was performed. gone. Table 1 shows the test results.
  • Comparative Example 4 The same operation as in Comparative Example 3 was performed using styrene/maleic acid ester (maleic acid-modified resin; Regit (registered trademark) SM-101 manufactured by Sanyo Chemical Industries, Ltd.) as a surface treatment agent. Table 1 shows the test results.
  • the samples of Examples 1 to 4 containing calcium carbonate surface-treated with a phosphate ester had a small amount of acetic acid elution, and were found to be suitable for food applications.
  • the sample of Example 1 surface-treated with a phosphoric acid ester having an ethylene oxide unit, especially polyoxyethylene lauryl ether phosphoric acid showed a significant reduction in the amount of acetic acid eluted.
  • the resin composition filled with a large amount of calcium carbonate tends to have a large acetic acid elution amount and a low tensile strength.
  • Example 5 Comparative Example 5
  • Example 1 The same operations as in Example 1 and Comparative Example 2 were performed, except that 70 parts by mass of surface-treated calcium carbonate and 30 parts by mass of polypropylene homopolymer were used. Table 2 shows the test results.
  • Example 6 The same operation as in Example 5 was performed except that the amount of phosphate ester during surface treatment was changed to 1 part by mass. Table 2 shows the test results.
  • Comparative Examples 7-8 The same operations as in Comparative Examples 3 and 4 were performed except that 70 parts by mass of surface-treated calcium carbonate and 30 parts by mass of polypropylene homopolymer were used. Table 2 shows the test results.
  • both the samples of Examples 5 and 6 containing calcium carbonate surface-treated with a phosphate ester have a smaller acetic acid elution amount than the sample of Comparative Example 5 containing general-purpose fatty acid-treated calcium carbonate. It was found to be suitable for food applications. Tensile properties were also good. On the other hand, in Comparative Examples 6 to 8, since the calcium carbonate particles were covered with the modified resin, the acetic acid elution amount was rather low, but the tensile properties were remarkably deteriorated. It was shown that the present invention has remarkable effects.
  • thermoplastic resin composition containing calcium carbonate surface-treated with a surface-treating agent containing a phosphate ester according to the present invention can be used under acidic conditions despite being highly filled with inorganic powder. It has been found that the elution amount is small, moldability is good, physical properties such as mechanical strength are excellent, and it is particularly suitable for food packaging containers and tableware.

Abstract

The present invention provides: a resin composition which is suppressed in the amount of dissolution under acidic conditions even if a thermoplastic resin is highly filled with calcium carbonate, while having good moldability and excellent physical properties such as mechanical strength, and which is particularly suitable for food packaging containers and dishes; and a molded article which is formed from this resin composition.　A resin composition which contains a thermoplastic resin and an inorganic material powder at a mass ratio of from 50:50 to 10:90, and which is characterized in that the inorganic material powder is calcium carbonate that is surface-treated with a surface treatment agent containing a phosphoric acid ester. It is preferable that the phosphoric acid ester is a polyoxyethylene lauryl ether phosphate.

Description

樹脂組成物及び成形品Resin composition and molded article
　本発明は、樹脂組成物及び成形品に関する。詳しく述べると、本発明は、熱可塑性樹脂中に炭酸カルシウムが高充填されているにも拘らず、酸性条件下での溶出量が少なく、成形性が良好で、機械的強度等の物性も優れる樹脂組成物、及びそうした樹脂組成物からなる成形品、特に食品包装容器及び食器に関する。 The present invention relates to resin compositions and molded articles. More specifically, in the present invention, although the thermoplastic resin is highly filled with calcium carbonate, the amount of elution under acidic conditions is small, the moldability is good, and physical properties such as mechanical strength are excellent. The present invention relates to resin compositions and molded articles made of such resin compositions, particularly food packaging containers and tableware.
　従来より、食品包装容器としては、その基材に紙やポリエステル、ポリプロピレン、発泡ポリスチレン等を用いて成形したものが広く用いられている。しかし、環境保護が国際的な問題となってきた現在、合成樹脂並びに紙資材の消費量を低減することが大いに検討されており、この様な観点から、無機物質粉末を熱可塑性樹脂中に高充填してなる樹脂組成物が提唱され（例えば、特許文献１等参照）、食品包装容器の分野においても応用が期待されている。無機物質粉末の内でも炭酸カルシウムは、人体への害がなく、日本国内でも豊富に産出されることから、これを充填した樹脂組成物は食品包装容器や食器への用途に有用である。 Conventionally, as food packaging containers, those molded using paper, polyester, polypropylene, expanded polystyrene, etc. as the base material have been widely used. However, now that environmental protection has become an international issue, reducing the consumption of synthetic resins and paper materials is being extensively studied. A filled resin composition has been proposed (see, for example, Patent Document 1), and is expected to be applied in the field of food packaging containers. Among inorganic substance powders, calcium carbonate is harmless to the human body and is abundantly produced in Japan. Therefore, a resin composition filled with calcium carbonate is useful for food packaging containers and tableware.
　しかし、上述した様な樹脂組成物により形成された食品包装容器にあっては、使用中に、無機物質粉末が脱落したり、食品、特に、強酸性の飲料等の液状食品へ、無機物質粉末として用いられる炭酸カルシウムが溶出する虞れがあることが課題となっていた。例えばｐＨが５以下の食品に用いられる樹脂製容器は、温酢酸への溶出量が少ないことが求められるが、炭酸カルシウムを多量配合した樹脂組成物では、この溶出量が大きくなりがちである。また、熱可塑性樹脂中に無機物質粉末が高充填されることで、当該包装容器中に微小な空隙が生じ易くなるため、ガスバリア性が乏しく、湿気、匂い移り、商品の鮮度保持の観点でも課題があり、耐油性も十分ではなかった。 However, in the food packaging container formed of the resin composition as described above, the inorganic substance powder falls off during use, and the inorganic substance powder falls off into the food, especially liquid food such as strongly acidic beverages. It has been a problem that there is a risk that calcium carbonate used as a elution. For example, a resin container used for food with a pH of 5 or less is required to have a small amount of elution in warm acetic acid, but a resin composition containing a large amount of calcium carbonate tends to have a large amount of elution. In addition, when the inorganic powder is highly filled in the thermoplastic resin, minute voids are likely to occur in the packaging container, resulting in poor gas barrier properties, moisture transfer, odor transfer, and problems in terms of keeping the product fresh. and the oil resistance was not sufficient.
　そのため、無機物質粉末を配合した樹脂組成物を食品包装容器に使用する場合、食品と接触する側又は両側に樹脂を積層した、２層又は３層構造とするのが一般的である。例えば特許文献２には、無機充填剤を５０質量％超含む内層の両面に、熱可塑性樹脂の外層を積層したシート状積層体が開示されている。 Therefore, when a resin composition containing inorganic substance powder is used for food packaging containers, it is common to have a two-layer or three-layer structure in which the resin is laminated on the side or both sides that come into contact with food. For example, Patent Literature 2 discloses a sheet-like laminate in which outer layers of a thermoplastic resin are laminated on both sides of an inner layer containing more than 50% by mass of an inorganic filler.
　また、樹脂組成物中での空隙の発生を抑制し、また、機械的強度を改善する手法として、無機物質粉末を表面処理する技術が知られている。特許文献２にも、炭酸カルシウム粒子の表面を、シランカップリング剤や金属石鹸で処理する技術が記載されている。ここで、表面処理技術自体は公知であり、例えば脂肪酸の他に樹脂酸やシラン、リン酸エステル等で表面処理した炭酸カルシウムが、非特許文献１や特許文献３及び４に記載されている。 In addition, as a technique for suppressing the generation of voids in the resin composition and improving the mechanical strength, a technique for surface-treating inorganic powder is known. Patent Document 2 also describes a technique of treating the surface of calcium carbonate particles with a silane coupling agent or a metallic soap. Here, the surface treatment technique itself is known, and for example, non-patent document 1, patent documents 3 and 4 describe calcium carbonate surface-treated with resin acid, silane, phosphate ester, etc., in addition to fatty acid.
国際公開第ＷＯ２０１４／１０９２６７号明細書International Publication No. WO2014/109267 特許第６８５７４２８号公報Japanese Patent No. 6857428 特表２０１６－５１３１５９号公報Japanese Patent Publication No. 2016-513159 特開平１１－３５７９０号公報JP-A-11-35790
　特許文献２記載のような積層体は、製造時に積層工程が必須となるため、生産性の点で難点がある。容器等の端部に表面層を設けることも困難であるため、酢酸溶出試験で良好な評価結果が得られない場合もある。樹脂積層体はコストも高くなりがちで、また、合成樹脂の消費量低減という環境保護への貢献もなし難くなる。無機物質粉末充填樹脂組成物からの溶出を、樹脂層を積層することなく抑制する技術が、求められている。 A laminate such as that described in Patent Document 2 requires a lamination process during manufacturing, which poses a problem in terms of productivity. Since it is also difficult to provide a surface layer on the edge of a container or the like, good evaluation results may not be obtained in the acetic acid elution test. The cost of the resin laminate tends to be high, and it is difficult to contribute to environmental protection by reducing the consumption of synthetic resin. A technique for suppressing elution from an inorganic substance powder-filled resin composition without laminating a resin layer is desired.
　特許文献２には、ステアリン酸カルシウム等での表面処理によって炭酸カルシウム粒子と熱可塑性樹脂の界面に空隙が発生することを抑制でき、積層体の成形性を向上できるとも記載されている。しかしながら、後記する実施例にも示すように、表面処理剤の選定が不適切だと、樹脂組成物の成形性や機械的特性は、むしろ低下する場合がある。 Patent Document 2 also states that surface treatment with calcium stearate or the like can suppress the formation of voids at the interface between the calcium carbonate particles and the thermoplastic resin, and improve the moldability of the laminate. However, as shown in the examples below, if the surface treatment agent is inappropriately selected, the moldability and mechanical properties of the resin composition may rather deteriorate.
　従来の表面処理手法の多くは、例えば非特許文献１におけるように、炭酸カルシウム配合量が熱可塑性樹脂等に比べて少量の系で検討されている。特許文献３では、表面処理した無機物質を最大で９５重量％含有するポリマー組成物も、記載されてはいる。しかし、成形品の機械的特性と表面処理法との関係については、実際には無機物質含有量が２０重量％以下の組成物でしか検討されていない。特許文献４では、シラン処理炭酸カルシウム等を多量充填した組成物に基づく電線シース層が記載されているものの、その機械的強度等の物性は評価されていない。このように、無機物質粉末を多量充填する樹脂組成物、特に食品用の樹脂組成物については、表面処理法と成形性や機械的特性との関係が、殆ど検討されていないのが現状である。 Many of the conventional surface treatment methods, such as Non-Patent Document 1, have been studied in systems with a smaller amount of calcium carbonate compounded compared to thermoplastic resins and the like. In US Pat. No. 5,400,005, polymer compositions containing up to 95% by weight of surface-treated inorganic substances are also described. However, the relationship between the mechanical properties of the molded article and the surface treatment method has actually been investigated only for compositions containing 20% by weight or less of inorganic substances. Although Patent Document 4 describes an electric wire sheath layer based on a composition filled with a large amount of silane-treated calcium carbonate or the like, its physical properties such as mechanical strength are not evaluated. As described above, with respect to resin compositions filled with a large amount of inorganic substance powder, especially resin compositions for food, the relationship between the surface treatment method and the moldability and mechanical properties has not been studied at present. .
　本発明は以上の実情に鑑みてなされたものであり、熱可塑性樹脂中に炭酸カルシウムが高充填されているにも拘らず、酸性条件下での溶出量が少なく、成形性が良好で、機械的強度等の物性も優れる、特に食品包装容器及び食器用に適する樹脂組成物、及びそうした樹脂組成物からなる成形品を提供することを課題とする。 The present invention has been made in view of the above-mentioned circumstances. An object of the present invention is to provide a resin composition which is excellent in physical properties such as physical strength and particularly suitable for food packaging containers and tableware, and a molded article made of such a resin composition.
　本発明者らは鋭意検討の結果、炭酸カルシウムを多量充填する樹脂組成物において、リン酸エステル類を含有する表面処理剤、特に特定構造のリン酸エステル類を主成分とする表面処理剤で炭酸カルシウム表面を処理することにより、樹脂組成物の物性を低下させることなく成形性を改善し、しかも酢酸等への溶出量を低減できることを見出し、本発明に到達したものである。 As a result of intensive studies, the present inventors have found that, in a resin composition filled with a large amount of calcium carbonate, a surface treatment agent containing a phosphate ester, particularly a surface treatment agent mainly composed of a phosphate ester having a specific structure, is used to produce carbonic acid. The inventors have found that by treating the surface of calcium, the moldability can be improved without deteriorating the physical properties of the resin composition, and the amount of elution into acetic acid and the like can be reduced, leading to the present invention.
　すなわち、上記課題を解決する本発明は、熱可塑性樹脂と無機物質粉末とを質量比５０：５０～１０：９０の割合で含有する樹脂組成物において、前記無機物質粉末は、リン酸エステルを含有する表面処理剤で表面処理された炭酸カルシウムであることを特徴とする樹脂組成物である。 That is, the present invention for solving the above problems is a resin composition containing a thermoplastic resin and an inorganic substance powder at a mass ratio of 50:50 to 10:90, wherein the inorganic substance powder contains a phosphate ester. A resin composition characterized by being calcium carbonate surface-treated with a surface-treating agent.
　本発明の樹脂組成物の一実施形態においては、前記リン酸エステルが、ポリオキシエチレンラウリルエーテルリン酸である樹脂組成物が示される。 In one embodiment of the resin composition of the present invention, the phosphate is polyoxyethylene lauryl ether phosphate.
　本発明の樹脂組成物の一実施形態においては、前記炭酸カルシウム粒子のＪＩＳ　Ｍ－８５１１に準じた空気透過法による比表面積の測定結果から計算した平均粒子径が、０．７μｍ以上６．０μｍ以下である樹脂組成物が示される。 In one embodiment of the resin composition of the present invention, the average particle diameter of the calcium carbonate particles calculated from the measurement results of the specific surface area by an air permeation method according to JIS M-8511 is 0.7 μm or more and 6.0 μm or less. A resin composition is shown.
　本発明の樹脂組成物の一実施形態においては、前記炭酸カルシウムが、重質炭酸カルシウムである樹脂組成物が示される。 In one embodiment of the resin composition of the present invention, the calcium carbonate is ground calcium carbonate.
　本発明の樹脂組成物の一実施形態においては、前記熱可塑性樹脂が、ポリオレフィン系樹脂である樹脂組成物が示される。 In one embodiment of the resin composition of the present invention, the thermoplastic resin is a polyolefin resin.
　本発明の樹脂組成物の一実施形態においては、前記ポリオレフィン系樹脂が、ポリエチレン系樹脂及び／又はポリプロピレン系樹脂からなる樹脂組成物が示される。 In one embodiment of the resin composition of the present invention, the polyolefin-based resin is a resin composition comprising a polyethylene-based resin and/or a polypropylene-based resin.
　本発明の樹脂組成物の一実施形態においては、前記のいずれかの樹脂組成物からなる成形品が示される。 　In one embodiment of the resin composition of the present invention, a molded article made of any of the above resin compositions is shown.
　本発明の樹脂組成物の一実施形態においては、前記のいずれかの樹脂組成物からなる食品包装容器が示される。 In one embodiment of the resin composition of the present invention, a food packaging container made of any one of the resin compositions described above is shown.
　本発明によれば、熱可塑性樹脂中に炭酸カルシウムが高充填されているにも拘らず、酸性条件下での溶出量が少なく、成形性が良好で、機械的強度等の物性も優れる樹脂組成物が提供される。本発明の樹脂組成物に基づく成形品は、特に食品包装容器及び食器用に好適である。 According to the present invention, the resin composition has a small amount of elution under acidic conditions, good moldability, and excellent physical properties such as mechanical strength, even though the thermoplastic resin is highly filled with calcium carbonate. goods are provided. Molded articles based on the resin composition of the present invention are particularly suitable for food packaging containers and tableware.
　以下、本発明を実施形態に基づき詳細に説明する。 The present invention will be described in detail below based on embodiments.
　本発明の樹脂組成物は、熱可塑性樹脂、及びリン酸エステルを含有する表面処理剤で表面処理された炭酸カルシウムを、質量比５０：５０～１０：９０の割合で含有する。以下、樹脂組成物中のこれら成分について説明する。 The resin composition of the present invention contains a thermoplastic resin and calcium carbonate surface-treated with a surface-treating agent containing a phosphate ester in a mass ratio of 50:50 to 10:90. These components in the resin composition are described below.
≪熱可塑性樹脂≫
　本発明の樹脂組成物において、熱可塑性樹脂の種類に特に制限はない。例として、ポリエチレン系樹脂、ポリプロピレン系樹脂、ポリメチル－１－ペンテン、エチレン－環状オレフィン共重合体等のポリオレフィン系樹脂；エチレン－酢酸ビニル共重合体、エチレン－アクリル酸共重合体、エチレン－メタクリル酸共重合体、エチレン－（メタ）アクリル酸共重合体の金属塩（アイオノマー）、エチレン－アクリル酸アルキルエステル共重合体、エチレン－メタクリル酸アルキルエステル共重合体、マレイン酸変性ポリエチレン、マレイン酸変性ポリプロピレン等の官能基含有ポリオレフィン系樹脂；ナイロン－６、ナイロン－６，６、ナイロン－６，１０、ナイロン－６，１２等のポリアミド系樹脂；ポリエチレンテレフタレート及びその共重合体、ポリエチレンナフタレート、ポリブチレンテレフタレート等の芳香族ポリエステル系樹脂、ポリ酢酸ビニル、ポリブチレンサクシネート、ポリ乳酸等の脂肪族ポリエステル系樹脂等の熱可塑性ポリエステル系樹脂；ポリ（メタ）アクリル酸（エステル）、ポリアクリロニトリル等のアクリル系樹脂；芳香族ポリカーボネート、脂肪族ポリカーボネート等のポリカーボネート樹脂；アタクティックポリスチレン、シンジオタクティックポリスチレン、アクリロニトリル－スチレン（ＡＳ）共重合体、アクリロニトリル－ブタジエン－スチレン（ＡＢＳ）共重合体等のポリスチレン系樹脂；ポリ塩化ビニル、ポリ塩化ビニリデン等のポリ塩化ビニル系樹脂；ポリフェニレンスルフィド；ポリエーテルスルフォン、ポリエーテルケトン、ポリエーテルエーテルケトン等のポリエーテル系樹脂；さらにはポリビニルアルコール、石油炭化水素樹脂、クマロンインデン樹脂等の種々の公知の熱可塑性樹脂が挙げられるが、これらに限定されない。複数種の熱可塑性樹脂を、併用することもできる。また、スチレン－ブタジエン共重合体、スチレン－イソプレン共重合体、スチレン－ブタジエン－エチレン共重合体、スチレン－イソプレン－エチレン共重合体、アクリロニトリル－ブタジエン共重合体、フッ素系エラストマー等のエラストマー成分を含有していても良い。 ≪Thermoplastic Resin≫
In the resin composition of the present invention, the type of thermoplastic resin is not particularly limited. Examples include polyethylene resins, polypropylene resins, polymethyl-1-pentene, polyolefin resins such as ethylene-cyclic olefin copolymers; ethylene-vinyl acetate copolymers, ethylene-acrylic acid copolymers, ethylene-methacrylic acid Copolymer, metal salt of ethylene-(meth)acrylic acid copolymer (ionomer), ethylene-alkyl acrylate copolymer, ethylene-alkyl methacrylate copolymer, maleic acid-modified polyethylene, maleic acid-modified polypropylene functional group-containing polyolefin resins such as; nylon-6, nylon-6,6, nylon-6,10, nylon-6,12 and other polyamide resins; polyethylene terephthalate and its copolymers, polyethylene naphthalate, polybutylene Aromatic polyester resins such as terephthalate, thermoplastic polyester resins such as aliphatic polyester resins such as polyvinyl acetate, polybutylene succinate, and polylactic acid; acrylics such as poly(meth)acrylic acid (ester) and polyacrylonitrile Polystyrene resins; Polycarbonate resins such as aromatic polycarbonates and aliphatic polycarbonates; Polystyrene resins such as atactic polystyrene, syndiotactic polystyrene, acrylonitrile-styrene (AS) copolymers, acrylonitrile-butadiene-styrene (ABS) copolymers polyvinyl chloride-based resins such as polyvinyl chloride and polyvinylidene chloride; polyphenylene sulfide; polyether-based resins such as polyether sulfone, polyether ketone, and polyether ether ketone; further polyvinyl alcohol, petroleum hydrocarbon resin, cumarone Examples include, but are not limited to, various known thermoplastic resins such as indene resins. A plurality of types of thermoplastic resins can also be used in combination. It also contains elastomer components such as styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-butadiene-ethylene copolymer, styrene-isoprene-ethylene copolymer, acrylonitrile-butadiene copolymer, fluorine-based elastomer, etc. It's okay to be
　これらの熱可塑性樹脂の内、その成形容易性、性能面、及び経済面等から、ポリオレフィン系樹脂が好ましい。 Among these thermoplastic resins, polyolefin resins are preferred in terms of moldability, performance, and economy.
　＜ポリオレフィン系樹脂＞
　ここで、ポリオレフィン系樹脂とは、オレフィン成分単位を主成分とするポリオレフィン系樹脂であり、具体的には、上記した様にポリプロピレン系樹脂やポリエチレン系樹脂、その他、ポリメチル－１－ペンテン、エチレン－環状オレフィン共重合体等、更にそれらの２種以上の混合物等が挙げられる。なお、上記「主成分とする」とは、オレフィン成分単位がポリオレフィン系樹脂中に５０質量％以上含まれることを意味し、その含有量は好ましくは７５質量％以上であり、より好ましくは８５質量％以上であり、更に好ましくは９０質量％以上である。特に、ポリオレフィンの単独重合体（ホモポリマー）が好ましい。なお、本発明に使用されるポリオレフィン系樹脂の製造方法は特に限定はなく、チーグラー・ナッタ系触媒、メタロセン系触媒、酸素、過酸化物等のラジカル開始剤等を用いる方法等の何れによって得られたものであっても良い。 <Polyolefin resin>
Here, the polyolefin-based resin is a polyolefin-based resin having olefin component units as a main component. Cyclic olefin copolymers and the like, and mixtures of two or more thereof are also included. The above-mentioned "mainly composed" means that the olefin component unit is contained in the polyolefin resin in an amount of 50% by mass or more, and the content is preferably 75% by mass or more, more preferably 85% by mass. % or more, more preferably 90 mass % or more. In particular, homopolymers (homopolymers) of polyolefins are preferred. The method for producing the polyolefin resin used in the present invention is not particularly limited, and can be obtained by any method using a Ziegler-Natta catalyst, a metallocene catalyst, a radical initiator such as oxygen or a peroxide, or the like. It may be something else.
　本発明の樹脂組成物は、これらポリオレフィン系樹脂として、ポリエチレン系樹脂及び／又はポリプロピレン系樹脂を含むことが好ましい。より好ましくは、熱可塑性樹脂が、実質的にポリエチレン系樹脂及び／又はポリプロピレン系樹脂からなる。これら樹脂は、物性、成形性、及びコストのバランスに特に優れ、本発明の樹脂組成物中の熱可塑性樹脂成分として好適である。特に、機械的強度と耐熱性とのバランスに特に優れることから、ポリプロピレン系樹脂が好ましく用いられる。 The resin composition of the present invention preferably contains a polyethylene-based resin and/or a polypropylene-based resin as these polyolefin-based resins. More preferably, the thermoplastic resin consists essentially of polyethylene-based resin and/or polypropylene-based resin. These resins are particularly excellent in the balance of physical properties, moldability, and cost, and are suitable as the thermoplastic resin component in the resin composition of the present invention. In particular, polypropylene-based resins are preferably used because they are particularly excellent in the balance between mechanical strength and heat resistance.
　前記ポリプロピレン系樹脂としては、プロピレン成分単位が５０質量％以上の樹脂が挙げられ、例えば、プロピレン単独重合体、又はプロピレンと共重合可能な他のモノマーとの共重合体等が挙げられる。プロピレン単独重合体としては、アイソタクティック、シンジオタクティック、アタクチック、ヘミアイソタクチック及び種々の立体規則性を示す直鎖又は分枝状ポリプロピレン等の何れもが包含される。また上記共重合体は、ランダム共重合体であってもブロック共重合体であっても良く、さらに二元共重合体のみならず三元共重合体であっても良い。共重合成分（他のモノマー）としては、エチレンや、１－ブテン、イソブチレン、１－ペンテン、３－メチル－１－ブテン、１－ヘキセン、３，４－ジメチル－１－ブテン、１－ヘプテン、３－メチル－１－ヘキセン等の炭素数４～１０のα－オレフィン；さらにはテトラフロロエチレンや酢酸ビニル等が挙げられるが、これらに限定されない。本発明においては、好ましくは単独重合体、あるいは他のモノマーが少量、例えば５質量％未満共重合した樹脂を使用する。なお、プロピレンの単独重合体においても、重合の結果として例えばヘキセン等のα－オレフィンが共重合したかのような構造が一部に含まれる場合があるが、本発明においてはそうした重合体をも、広くプロピレン単独重合体（プロピレンホモポリマー）として包含する。これらのポリプロピレン系樹脂は、単独又は２種以上を混合して用いることができる。 Examples of the polypropylene-based resin include resins having a propylene component unit of 50% by mass or more, such as propylene homopolymers and copolymers of propylene and other copolymerizable monomers. Propylene homopolymers include isotactic, syndiotactic, atactic, hemiisotactic, and linear or branched polypropylenes exhibiting various stereoregularities. The above copolymer may be a random copolymer or a block copolymer, and may be a terpolymer as well as a binary copolymer. Copolymerization components (other monomers) include ethylene, 1-butene, isobutylene, 1-pentene, 3-methyl-1-butene, 1-hexene, 3,4-dimethyl-1-butene, 1-heptene, α-olefins having 4 to 10 carbon atoms such as 3-methyl-1-hexene; furthermore, tetrafluoroethylene, vinyl acetate and the like, but are not limited thereto. In the present invention, it is preferable to use a homopolymer or a resin copolymerized with a small amount of another monomer, for example, less than 5% by weight. It should be noted that even in propylene homopolymers, as a result of polymerization, there are cases where a structure as if an α-olefin such as hexene is copolymerized is partly included, but in the present invention, such a polymer is also included. , is broadly included as a propylene homopolymer (propylene homopolymer). These polypropylene-based resins can be used alone or in combination of two or more.
　また、前記ポリエチレン系樹脂としては、エチレン成分単位が５０質量％以上の樹脂が挙げられ、例えば、高密度ポリエチレン（ＨＤＰＥ）、低密度ポリエチレン（ＬＤＰＥ）、中密度ポリエチレン、直鎖状低密度ポリエチレン（ＬＬＤＰＥ）、エチレン－酢酸ビニル共重合体、エチレン－プロピレン共重合体、エチレン－プロピレン－ブテン１共重合体、エチレン－ブテン１共重合体、エチレン－ヘキセン１共重合体、エチレン－４メチルペンテン１共重合体、エチレン－オクテン１共重合体等、さらにそれらの２種以上の混合物が挙げられる。 Examples of the polyethylene-based resin include resins having an ethylene component unit of 50% by mass or more. Examples include high-density polyethylene (HDPE), low-density polyethylene (LDPE), medium-density polyethylene, linear low-density polyethylene ( LLDPE), ethylene-vinyl acetate copolymer, ethylene-propylene copolymer, ethylene-propylene-butene 1 copolymer, ethylene-butene 1 copolymer, ethylene-hexene 1 copolymer, ethylene-4 methylpentene 1 Copolymers, ethylene-octene 1 copolymers, etc., and mixtures of two or more thereof are also included.
≪無機物質粉末≫
　本発明の樹脂組成物に含有される無機物質粉末は、リン酸エステルを含有する表面処理剤で表面処理された炭酸カルシウムである。 ≪Inorganic substance powder≫
The inorganic powder contained in the resin composition of the present invention is calcium carbonate surface-treated with a surface-treating agent containing a phosphate ester.
　＜炭酸カルシウム＞
　炭酸カルシウムとしては、合成法により調製されたもの（いわゆる軽質炭酸カルシウム）、石灰石等のＣａＣＯ３を主成分とする天然原料を機械的に粉砕分級して得られるもの（いわゆる重質炭酸カルシウム）の何れであっても良く、これらを組み合わせて用いても良い。その形状としても、特に限定されるわけではなく、粒子状、フレーク状、顆粒状、繊維状等の何れであっても良い。また、粒子状としても、一般的に合成法により得られるような球形のものであっても、あるいは、採集した天然鉱物を粉砕にかけることにより得られるような不定形状のものであっても良い。 <Calcium carbonate>
Calcium carbonate includes those prepared by a synthetic method (so-called light calcium carbonate) and those obtained by mechanically pulverizing and classifying natural raw materials containing CaCO3 as a main component such as limestone (so-called heavy calcium carbonate). Any of them may be used, and these may be used in combination. The shape thereof is not particularly limited, and may be in the form of particles, flakes, granules, fibers, or the like. As for the particulate form, it may be spherical as generally obtained by a synthetic method, or irregularly shaped as obtained by pulverizing collected natural minerals. .
　炭酸カルシウムとしては、特に限定される訳ではないが、その平均粒子径が、０．７μｍ以上６．０μｍ以下が好ましく、０．８μｍ以上５．０μｍ以下がより好ましく、さらに好ましくは、１．０μｍ以上４．０μｍ以下である。なお、本明細書において述べる炭酸カルシウム等の無機物質粉末の平均粒子径は、ＪＩＳ　Ｍ－８５１１に準じた空気透過法による比表面積の測定結果から計算した値をいう。測定機器としては、例えば、島津製作所製の比表面積測定装置ＳＳ－１００型を好ましく用いることができる。平均粒子径が６．０μｍよりも大きくなると、例えばシート状の成形品を形成した場合に、その成形品の層厚にもよるが、成形品表面より無機物質粉末が突出して、当該粉末が脱落したり、表面性状や機械的強度等を損なう虞れがある。特に、その粒径分布において、粒子径４５μｍ以上の粒子を含有しないことが好ましい。他方、粒子が細かくなり過ぎると、前述した樹脂と混練した際に粘度が著しく上昇し、成形品の製造が困難になる虞れがある。そうした問題は、無機物質粉末の平均粒子径を０．７μｍ以上、特に０．８μｍ以上６．０μｍ以下とすることによって、防ぐことが可能となる。 Although calcium carbonate is not particularly limited, its average particle size is preferably 0.7 μm or more and 6.0 μm or less, more preferably 0.8 μm or more and 5.0 μm or less, and still more preferably 1.0 μm. It is more than 4.0 micrometers or less. In addition, the average particle size of the inorganic substance powder such as calcium carbonate described in this specification refers to a value calculated from the measurement result of the specific surface area by the air permeation method according to JIS M-8511. As a measuring device, for example, a specific surface area measuring device SS-100 manufactured by Shimadzu Corporation can be preferably used. If the average particle size is larger than 6.0 μm, for example, when a sheet-like molded product is formed, the inorganic powder protrudes from the surface of the molded product and falls off, depending on the layer thickness of the molded product. Otherwise, the surface properties, mechanical strength, etc. may be impaired. In particular, it is preferable that the particle size distribution does not contain particles having a particle size of 45 μm or more. On the other hand, if the particles are too fine, the viscosity will increase significantly when kneaded with the above-mentioned resin, which may make it difficult to produce molded articles. Such a problem can be prevented by setting the average particle size of the inorganic powder to 0.7 μm or more, particularly 0.8 μm or more and 6.0 μm or less.
　本発明において炭酸カルシウムは、ＪＩＳ　Ｍ－８５１１による空気透過法により測定した平均粒子径が０．７μｍ以上２．０μｍ未満、特に０．８μｍ以上２．０μｍ未満である第１の炭酸カルシウムと、ＪＩＳ　Ｍ－８５１１による空気透過法により測定した平均粒子径が２．０μｍ以上６．０μｍ以下、特に２．０μｍ以上５．０μｍ以下である第２の炭酸カルシウムとを含有しても良い。このことによって、成形品の表面性状や、印刷性、ブロッキング性等の物性を改善することができる。また、炭酸カルシウムの偏在が抑制され、外観及び、破断伸び等の機械的特性が良好な成形品を得ることができ、樹脂組成物成形品からの炭酸カルシウムの脱落を低減することも可能となる。特に限定されるわけではないが、第１の炭酸カルシウムの平均粒子径をａとし、第２の炭酸カルシウムの平均粒子径をｂとした場合に、ａ／ｂ比率が０．８５以下、より好ましくは０．１０～０．７０、さらに好ましくは０．１０～０．５０程度となるように大別できるものであることが望ましい。このようなある程度明確な平均粒子径の差をもったものを併用することで、特に優れた効果が期待できるためである。また、第１の炭酸カルシウムと第２の炭酸カルシウムのそれぞれは、その粒子径（μｍ）の分布の変動係数（Ｃｖ）が０．０１～０．１０程度であることが望ましく、特に０．０３～０．０８程度であることが望ましい。変動係数（Ｃｖ）で規定される粒子径のばらつきがこの程度であれば、各粉末群がより相補的に効果を与え得ると考えられる。第１の炭酸カルシウムと第２の炭酸カルシウムとの質量比は、９０：１０～９８：２、特に９２：８～９５：５程度とすることが好ましい。平均粒子径分布が異なる炭酸カルシウム群として、３つ以上のものを使用しても良い。 In the present invention, calcium carbonate is a first calcium carbonate having an average particle size of 0.7 μm or more and less than 2.0 μm, particularly 0.8 μm or more and less than 2.0 μm, as measured by an air permeation method according to JIS M-8511; It may also contain a second calcium carbonate having an average particle size of 2.0 μm or more and 6.0 μm or less, particularly 2.0 μm or more and 5.0 μm or less, as measured by an air permeation method using M-8511. As a result, it is possible to improve the physical properties such as the surface properties of the molded product and the printability and blocking property. In addition, uneven distribution of calcium carbonate is suppressed, a molded article having good appearance and mechanical properties such as elongation at break can be obtained, and it is also possible to reduce dropout of calcium carbonate from the resin composition molded article. . Although not particularly limited, when the average particle size of the first calcium carbonate is a and the average particle size of the second calcium carbonate is b, the a/b ratio is 0.85 or less, more preferably. is roughly 0.10 to 0.70, more preferably 0.10 to 0.50. This is because a particularly excellent effect can be expected by jointly using particles having such a clear difference in average particle size to some extent. Further, each of the first calcium carbonate and the second calcium carbonate preferably has a coefficient of variation (Cv) of the distribution of particle diameters (μm) of about 0.01 to 0.10, particularly 0.03. It is desirable to be about 0.08. If the variation in particle size defined by the coefficient of variation (Cv) is this level, it is considered that each powder group can provide more complementary effects. The mass ratio of the first calcium carbonate to the second calcium carbonate is preferably about 90:10 to 98:2, more preferably about 92:8 to 95:5. Three or more calcium carbonate groups having different average particle size distributions may be used.
　本発明において炭酸カルシウムは、重質炭酸カルシウムを含むことが好ましい。より好ましくは、重質炭酸カルシウム及びその不可避的不純物により、本発明の樹脂組成物における無機物質粉末が構成される。ここで、重質炭酸カルシウムとは、天然の石灰石等を機械的に粉砕・加工して得られるものであって、化学的沈殿反応等によって製造される合成炭酸カルシウムとは明確に区別される。なお、粉砕方法には乾式法と湿式法とがあるが、乾式法によるものが好ましい。 In the present invention, calcium carbonate preferably contains ground calcium carbonate. More preferably, the inorganic substance powder in the resin composition of the present invention is composed of heavy calcium carbonate and its unavoidable impurities. Here, heavy calcium carbonate is obtained by mechanically pulverizing and processing natural limestone or the like, and is clearly distinguished from synthetic calcium carbonate produced by chemical precipitation reaction or the like. The pulverization method includes a dry method and a wet method, and the dry method is preferred.
　重質炭酸カルシウムは、例えば、合成法による軽質炭酸カルシウムとは異なり、粒子形成が粉砕処理によって行われたことに起因する、表面の不定形性、比表面積の大きさに特徴を有する。重質炭酸カルシウムがこの様に不定形性、比表面積の大きさを有するため、熱可塑性樹脂中に配合した場合に重質炭酸カルシウムは、熱可塑性樹脂に対してより多くの接触界面を有し、均一分散に効果がある。 Unlike synthetic light calcium carbonate, for example, ground calcium carbonate is characterized by surface irregularities and a large specific surface area due to the fact that particles are formed by a pulverization process. Since ground calcium carbonate has such an irregular shape and a large specific surface area, when blended in a thermoplastic resin, ground calcium carbonate has a larger contact interface with the thermoplastic resin. , is effective for uniform dispersion.
　特に限定されるわけではないが、上記炭酸カルシウムの比表面積としては、その平均粒子径によっても左右されるが、３,０００ｃｍ２／ｇ以上３５,０００ｃｍ２／ｇ以下程度であることが望まれる。ここでいう比表面積は空気透過法によるものである。比表面積がこの範囲内にあると、得られる成形品の加工性低下が抑制される傾向がある。 Although not particularly limited, the specific surface area of the calcium carbonate is desirably about 3,000 cm 2 /g or more and 35,000 cm 2 /g or less, though it depends on the average particle size. . The specific surface area referred to here is obtained by the air permeation method. When the specific surface area is within this range, there is a tendency to suppress deterioration in processability of the obtained molded article.
　また、炭酸カルシウム粒子の不定形性は、粒子形状の球形化の度合いが低いことで表わすことが出来、特に限定されるわけではないが、具体的には、真円度が０．５０以上０．９５以下、より好ましくは０．５５以上０．９３以下、さらに好ましくは０．６０以上０．９０以下である。炭酸カルシウム粒子の真円度がこの範囲内にあると、成形品の強度や成形加工性も適度なものとなる。なお、ここで、真円度とは、（粒子の投影面積）／（粒子の投影周囲長と同一周囲長を持つ円の面積）で表せるものである。真円度の測定方法は特に限定されず、例えば顕微鏡写真から粒子の投影面積と粒子の投影周囲長とを測定しても良く、一般に商用されている画像解析ソフトを用いても良い。 In addition, the irregularity of the calcium carbonate particles can be represented by a low degree of spheroidization of the particle shape, and is not particularly limited. 0.95 or less, more preferably 0.55 or more and 0.93 or less, and still more preferably 0.60 or more and 0.90 or less. If the circularity of the calcium carbonate particles is within this range, the strength and molding processability of the molded article will be moderate. Here, the circularity can be expressed by (the projected area of the grain)/(the area of the circle having the same circumferential length as the projected circumferential length of the grain). The method for measuring the roundness is not particularly limited, and for example, the projected area and the projected peripheral length of the grain may be measured from a micrograph, or image analysis software that is generally commercially available may be used.
　＜表面処理＞
　本発明においては、上記のような炭酸カルシウムは、リン酸エステルを含有する表面処理剤で、少なくとも一部が表面処理されている。こうした表面処理（表面改質）により、炭酸カルシウムの分散性や反応性を高め、樹脂組成物の物性や成形性を改善することができる。しかも、脂肪酸等の汎用表面処理剤により改質された炭酸カルシウムとは異なり、熱可塑性樹脂中に高充填されても、機械的特性や酸性条件下での溶出等の物性がバランス良く優れ、食品包装容器及び食器用に好適な樹脂組成物を与える。 <Surface treatment>
In the present invention, the above calcium carbonate is at least partly surface-treated with a surface-treating agent containing a phosphate ester. By such surface treatment (surface modification), the dispersibility and reactivity of calcium carbonate can be enhanced, and the physical properties and moldability of the resin composition can be improved. Moreover, unlike calcium carbonate that has been modified with general-purpose surface treatment agents such as fatty acids, even when it is highly filled in a thermoplastic resin, it has excellent physical properties such as mechanical properties and elution under acidic conditions in a well-balanced manner. A resin composition suitable for packaging containers and tableware is provided.
　＜リン酸エステル表面処理剤＞
　本発明において「リン酸エステルを含有する表面処理剤」とは、リン酸ベースのエステルを含有する表面処理剤を全て包含する。リン酸ベースのエステルの例として、リン酸とアルコールとのモノエステル、ジエステル、トリエステル；リン酸とフェノールとのモノエステル、ジエステル、トリエステル；リン酸とアルキルフェノールとのモノエステル、ジエステル、トリエステル；リン酸とアルコールとアルキレンオキシドとのモノエステル、ジエステル、トリエステル、例えばリン原子にアルキルオキシ基とアルキルオキシアルキレンオキシ基とヒドロキシ基とが結合した構造のリン酸エステル；さらにカルボキシ基やカルボニル基を有する構造のリン酸エステル；及びそれらの塩、例えばナトリウム塩、カリウム塩、アンモニウム塩等が挙げられるが、これらに限定されない。これらリン酸エステルを、複数種併用することもできる。さらには、これらリン酸エステルと共に、脂肪酸や樹脂酸、無水脂肪酸変性樹脂等を含有する表面処理剤であっても良い。 <Phosphate ester surface treatment agent>
In the present invention, "a surface treatment agent containing a phosphoric acid ester" includes all surface treatment agents containing a phosphoric acid-based ester. Examples of phosphoric acid-based esters include monoesters, diesters and triesters of phosphoric acid and alcohols; monoesters, diesters and triesters of phosphoric acid and phenols; monoesters, diesters and triesters of phosphoric acid and alkylphenols. monoesters, diesters, and triesters of phosphoric acid, alcohols, and alkylene oxides, e.g., phosphoric acid esters having a structure in which an alkyloxy group, an alkyloxyalkyleneoxy group, and a hydroxy group are bonded to a phosphorus atom; and salts thereof, such as sodium salts, potassium salts, ammonium salts, etc., but are not limited thereto. A plurality of types of these phosphate esters can also be used in combination. Furthermore, surface treatment agents containing fatty acids, resin acids, fatty acid anhydride-modified resins, etc., together with these phosphate esters may be used.
　＜リン酸エステル＞
　本発明においてリン酸エステルは、モノエステル、ジエステル、もしくはそれらの塩、又はそれらの２種もしくは３種以上の混合物であることが好ましい。一般にモノエステルやジエステルを含有する表面処理剤であれば、炭酸カルシウム表面の改質効果が大となる。本発明は特定の理論に限定されるものではないが、モノエステルやジエステルは、分子中の＞Ｐ（＝Ｏ）－Ｏ－基を介して、炭酸カルシウム表面に強固に反応又は吸着するものと考えられる。また、一般に、脂肪族炭化水素鎖長が長い方が熱可塑性樹脂との相溶性に優れる傾向があり、本発明の効果が特に顕著なものとなる。そのため、分子中に長鎖脂肪族炭化水素基を有するリン酸エステル、例えばリン酸と長鎖アルコールとのモノエステル、ジエステル、トリエステル；リン酸と長鎖アルキルフェノールとのモノエステル、ジエステル、トリエステル；リン酸と長鎖アルコールとアルキレンオキシドとのモノエステル、ジエステル、トリエステル；及びそれらの塩から選択される１種以上のリン酸エステルを含有する表面処理剤が好ましい。より好ましくは、リン酸と長鎖アルコールとのモノエステル及びジエステル、リン酸と長鎖アルコールとアルキレンオキシドとのモノエステル及びジエステル、並びにそれらの塩から選択される１種以上のリン酸エステルである。 <Phosphate ester>
In the present invention, the phosphate ester is preferably a monoester, a diester, a salt thereof, or a mixture of two or more thereof. In general, surface treatment agents containing monoesters and diesters are effective in modifying the surface of calcium carbonate. Although the present invention is not limited to any particular theory, it is believed that monoesters and diesters strongly react or adsorb to the surface of calcium carbonate via >P(=O)-O- groups in the molecules. Conceivable. Further, in general, the longer the aliphatic hydrocarbon chain length, the more excellent the compatibility with the thermoplastic resin tends to be, and the effect of the present invention is particularly remarkable. Therefore, phosphoric acid esters having long-chain aliphatic hydrocarbon groups in the molecule, such as monoesters, diesters and triesters of phosphoric acid and long-chain alcohols; monoesters, diesters and triesters of phosphoric acid and long-chain alkylphenols. monoesters, diesters, triesters of phosphoric acid, long-chain alcohols and alkylene oxides; and salts thereof. More preferably, it is one or more phosphoric acid esters selected from monoesters and diesters of phosphoric acid and long-chain alcohols, monoesters and diesters of phosphoric acid, long-chain alcohols and alkylene oxide, and salts thereof. .
　上記リン酸エステル中の脂肪族炭化水素基に特に制限はなく、飽和又は不飽和の直鎖状、分岐状、又は環状の脂肪族炭化水素基全てを包含する。ヒドロキシ基やアルコキシ基、アミノ基、ニトロ基、シアノ基等で置換されていても良い。例として、イソプロピル基、ブチル基、ヘキシル基、ｎ－オクチル基、イソオクチル基、デシル基、ドデシル基（ラウリル基）、ペンタデシル基（ミリスチル基）、テトラデシル基（ミリスチル基）、ヘキサデシル基（パルミチル基）、オクタデシル基（ステアリル基）、ヘキサデセニル基（パルミトレイル基）、オクタデセニル基（オレイル基）、オクタデカジエニル基（リノレイル基、エライドリノレニル基）、オクタデカトリエニル基（リノレニル基）、ヒドロキシオクタデセニル基（リノレイル基）等が挙げられるが、これらに限定されない。脂肪族炭化水素基の炭素数にも特に制限はなく、例えば炭素数３～２０、中でも８～１８、特に１０～１４の脂肪族炭化水素基であっても良い。 The aliphatic hydrocarbon group in the phosphate ester is not particularly limited, and includes all saturated or unsaturated linear, branched, or cyclic aliphatic hydrocarbon groups. It may be substituted with a hydroxy group, an alkoxy group, an amino group, a nitro group, a cyano group, or the like. Examples include isopropyl group, butyl group, hexyl group, n-octyl group, isooctyl group, decyl group, dodecyl group (lauryl group), pentadecyl group (myristyl group), tetradecyl group (myristyl group), hexadecyl group (palmityl group). , octadecyl group (stearyl group), hexadecenyl group (palmitoleyl group), octadecenyl group (oleyl group), octadecadienyl group (linoleyl group, elaidolinolenyl group), octadecatrienyl group (linolenyl group), hydroxy octadecenyl group (linoleyl group) and the like, but not limited thereto. The number of carbon atoms in the aliphatic hydrocarbon group is also not particularly limited, and may be, for example, an aliphatic hydrocarbon group having 3 to 20 carbon atoms, especially 8 to 18 carbon atoms, especially 10 to 14 carbon atoms.
　本発明において、リン酸エステルは特に、リン酸とアルコールとアルキレンオキシドとのモノエステル、ジエステル、及び／又はそれらの塩であることが好ましい。例えば、式１：［ＣｘＨ２ｘ＋１Ｏ（ＣｙＨ２ｙＯ）ｚ］ｎＰ（＝Ｏ）（ＯＨ）ｍ　のような化合物やその塩（式１中、ｘ、ｙ、及びｚは１以上の整数であり；ｎ及びｍは１又は２で、ｎ＋ｍ＝３である。）であるが、これらに限定されない。リン酸エステルの炭化水素基（ＣｘＨ２ｘ＋１相当部）が、例えば不飽和結合や環状構造を備えて水素原子数が２ｘ－１以下であっても良く、また、分岐構造や、ヒドロキシ基等の置換基を有していても良い。こうしたリン酸エステルによれば、炭酸カルシウム表面を特に有効に改質することができ、酸性条件下での溶出量が少なく、機械的強度等の物性が良好な樹脂組成物を得ることが可能となる。本発明は特定の理論により限定されるものではないが、分子中にアルキレンオキシド単位を有することによって、炭酸カルシウム表面上のリン酸エステルから脂肪族炭化水素基がより広範囲に広がり、その結果、表面処理炭酸カルシウムと熱可塑性樹脂との相溶性が良好となっていると考えられる。 In the present invention, the phosphoric acid ester is particularly preferably monoester, diester and/or salt thereof of phosphoric acid, alcohol and alkylene oxide. For example, a compound such as Formula 1: [ CxH2x +1O ( CyH2yO ) z ] nP (=O)(OH) m or a salt thereof (wherein x, y, and z are 1 n and m are 1 or 2, and n+m=3), but are not limited thereto. The hydrocarbon group (corresponding to C x H 2x+1 ) of the phosphate ester may have, for example, an unsaturated bond or a cyclic structure, and the number of hydrogen atoms may be 2x-1 or less. may have a substituent of According to such a phosphate ester, the surface of calcium carbonate can be particularly effectively modified, the amount of elution under acidic conditions is small, and it is possible to obtain a resin composition having good physical properties such as mechanical strength. Become. Although the present invention is not limited by any particular theory, having an alkylene oxide unit in the molecule causes the aliphatic hydrocarbon group to spread more widely from the phosphate ester on the calcium carbonate surface, resulting in the surface It is considered that the compatibility between the treated calcium carbonate and the thermoplastic resin is good.
　上記のようなリン酸エステルにおいても、脂肪族炭化水素基の炭素数（例えば上記式１中のｘ）に特に制限はないが、３～２０、中でも８～１８、特に１０～１４であることが好ましい。より好ましくは、ポリオキシエチレンラウリルエーテルリン酸やその塩を使用する。アルキレンオキシドの種類にも特に制限はないが、エチレンオキシド、プロピレンオキシド、及びブチレンオキシドが、特にエチレンオキシド（上記式１においてｙ＝２）が好ましい。アルキレンオキシド単位の数（式１におけるｚ）にも特に制限はなく、例えば上記のような各脂肪族炭化水素基とリン原子との間に、アルキレンオキシド単位を１～１２個、特に１～４個有するものが好ましい。さらに好ましくは、ポリオキシエチレン（１～４）ラウリルエーテルリン酸及び／又はその塩を、特に好ましくは、モノポリオキシエチレン（２）ラウリルエーテルリン酸、ジポリオキシエチレン（２）ラウリルエーテルリン酸、及びそれらの塩から選択される１種以上のリン酸エステルを使用する。 In the above phosphoric acid ester, the number of carbon atoms in the aliphatic hydrocarbon group (eg, x in formula 1) is not particularly limited, but it should be 3 to 20, especially 8 to 18, especially 10 to 14. is preferred. More preferably, polyoxyethylene lauryl ether phosphate or its salt is used. Although the type of alkylene oxide is not particularly limited, ethylene oxide, propylene oxide, and butylene oxide are preferred, and ethylene oxide (y=2 in formula 1 above) is particularly preferred. The number of alkylene oxide units (z in Formula 1) is also not particularly limited. For example, 1 to 12 alkylene oxide units, particularly 1 to 4 Individual ones are preferred. More preferably, polyoxyethylene (1-4) lauryl ether phosphate and/or salts thereof, particularly preferably monopolyoxyethylene (2) lauryl ether phosphate, dipolyoxyethylene (2) lauryl ether phosphate, and salts thereof.
　＜表面処理法＞
　上記のようなリン酸エステルによる炭酸カルシウムの表面処理方法に特に制限はなく、種々の公知の表面処理法を援用することができる。例えば、炭酸カルシウムのスラリーにリン酸エステルを加えて攪拌する方法（湿式法）、粉砕機やミキサー中に炭酸カルシウムとリン酸エステルとを入れ、所望により加熱しながら攪拌する方法（乾式法）、さらには炭酸カルシウムの含水ケーキとリン酸エステルとを、ミキサー中で加熱しながら攪拌する方法等が挙げられるが、これらに限定されない。表面処理剤として使用するリン酸エステルの種類にもよるが、一般に軽質炭酸カルシウムの表面処理は湿式法で、重質炭酸カルシウムの表面処理は乾式法で行うのが好ましい。 <Surface treatment method>
There is no particular limitation on the surface treatment method of calcium carbonate with the phosphate ester as described above, and various known surface treatment methods can be employed. For example, a method of adding a phosphoric acid ester to a slurry of calcium carbonate and stirring (wet method), a method of adding calcium carbonate and a phosphoric acid ester to a grinder or a mixer, and optionally heating and stirring (dry method), Furthermore, a method of stirring a hydrous cake of calcium carbonate and a phosphoric acid ester while heating them in a mixer may be used, but the methods are not limited to these. Depending on the type of phosphate ester used as the surface treatment agent, it is generally preferable to carry out the surface treatment of light calcium carbonate by a wet method and the surface treatment of heavy calcium carbonate by a dry method.
　表面処理の際の、炭酸カルシウムに対するリン酸エステルの量比に、特に制限はない。しかしながら、炭酸カルシウム１００質量部に対し、リン酸エステルの量を０．２～１０質量部、特に０．５～５質量部、中でも１～３質量部程度とするのが好ましい。こうしたリン酸エステル量であれば、炭酸カルシウム表面を均一に改質することが容易となり、また、余剰のリン酸エステルが使用時に溶出するリスクを低減することができる。なお、炭酸カルシウム表面のリン酸エステル量は、溶剤抽出や熱分解ＧＣ／ＭＳ等の公知の分析方法によって定量することができる。 There is no particular limitation on the amount ratio of phosphate ester to calcium carbonate during surface treatment. However, it is preferable that the amount of the phosphate ester is 0.2 to 10 parts by mass, particularly 0.5 to 5 parts by mass, more preferably about 1 to 3 parts by mass, based on 100 parts by mass of calcium carbonate. With such an amount of phosphate, it becomes easy to uniformly modify the surface of calcium carbonate, and the risk of excess phosphate eluting during use can be reduced. The amount of phosphate on the surface of calcium carbonate can be quantified by a known analysis method such as solvent extraction or pyrolysis GC/MS.
　湿式法により表面処理する場合、スラリー中の炭酸カルシウム濃度や溶媒の種類に特に制限はない。好ましくは、炭酸カルシウム濃度１０～３００ｇ／Ｌ、特に２５～２００ｇ／Ｌ程度の水性スラリーとする。こうした濃度であれば、表面処理の生産性が高められ、また、粘度が高くなって作業性が低下することもない。水性溶媒を用いることにより、表面処理を簡便かつ低コストで行うことができ、また、処理温度を高めても安全性を保持することができる。湿式法におけるスラリー温度は、好ましくは２０～９８℃、より好ましくは４０～９０℃、さらに好ましくは６０～８０℃とする。表面処理を２０℃以上で行うことにより、表面処理剤を炭酸カルシウム上に均一に吸着結合させることが可能となり、均一に表面処理することができる。また、スラリー温度を９８℃以下とすれば、突沸等のリスクがなく、耐圧性の装置も不要となる。なお、湿式法での表面処理において、スラリー中に界面活性剤を含有させても良い。 When surface treatment is performed by a wet method, there are no particular restrictions on the concentration of calcium carbonate in the slurry or the type of solvent. Preferably, the aqueous slurry has a calcium carbonate concentration of 10 to 300 g/L, particularly 25 to 200 g/L. With such a concentration, the productivity of surface treatment is enhanced, and the workability is not lowered due to an increase in viscosity. By using an aqueous solvent, the surface treatment can be performed simply and at low cost, and safety can be maintained even if the treatment temperature is raised. The slurry temperature in the wet method is preferably 20 to 98°C, more preferably 40 to 90°C, still more preferably 60 to 80°C. By carrying out the surface treatment at 20° C. or higher, the surface treatment agent can be uniformly adsorbed and bonded onto the calcium carbonate, and the surface can be treated uniformly. Also, if the slurry temperature is 98° C. or lower, there is no risk of bumping or the like, and a pressure-resistant device is not required. In addition, in the surface treatment by the wet method, the slurry may contain a surfactant.
　乾式法による表面処理は、例えばヘンシェルミキサーやニーダー、押出混練機等の混練機中で、炭酸カルシウムとリン酸エステルとを混練することによって行うことができる。特に、重質炭酸カルシウムを用いる場合は、粉砕機中に所望のリン酸エステルを添加し、炭酸カルシウムの粒径調整と同時に表面処理を行うこともできる。ここで、表面処理時の温度は、使用するリン酸エステルの種類に応じて任意に設定することができるが、一般に２０～１５０℃、特に４０～１３０℃、さらには６０～１２０℃程度とするのが好ましい。表面処理を２０℃以上で行うことにより、表面処理剤を炭酸カルシウム上に均一に吸着結合させることが可能となり、均一に表面処理することができる。また、処理温度が１５０℃程度以下であれば、表面処理剤の熱劣化や変質のリスクを低減できる。より好ましくは、使用するリン酸エステルの融点以上の温度で処理する。このことによって、表面処理剤は炭酸カルシウム上により均一に吸着結合し得る。例えば、ポリオキシエチレンラウリルエーテルリン酸等は室温で液状であるので、表面処理は室温で行うこともできる。ポリオキシエチレンステアリルエーテルリン酸等を用いた場合には、５０～１５０℃程度の温度で混練しても良い。なお、乾式法においても少量の溶媒を併用することができ、例えばリン酸エステル、特に塩型のリン酸エステルの水溶液を炭酸カルシウムに加えて、上記のように混練又は粉砕しても良い。 The surface treatment by the dry method can be performed by kneading calcium carbonate and phosphate ester in a kneader such as a Henschel mixer, kneader, or extrusion kneader. In particular, when heavy calcium carbonate is used, a desired phosphoric acid ester can be added to the grinder, and surface treatment can be performed at the same time as adjusting the particle size of the calcium carbonate. Here, the temperature during the surface treatment can be arbitrarily set according to the type of phosphate ester used, but is generally about 20 to 150°C, particularly 40 to 130°C, and further about 60 to 120°C. is preferred. By carrying out the surface treatment at 20° C. or higher, the surface treatment agent can be uniformly adsorbed and bonded onto the calcium carbonate, and the surface can be treated uniformly. Moreover, if the treatment temperature is about 150° C. or lower, the risk of thermal deterioration and deterioration of the surface treatment agent can be reduced. More preferably, the temperature is higher than the melting point of the phosphate used. This allows the surface treatment agent to more uniformly adsorb and bind onto the calcium carbonate. For example, since polyoxyethylene lauryl ether phosphate or the like is liquid at room temperature, the surface treatment can be performed at room temperature. When polyoxyethylene stearyl ether phosphate or the like is used, it may be kneaded at a temperature of about 50 to 150°C. In addition, a small amount of solvent can be used in combination even in the dry method. For example, an aqueous solution of a phosphoric acid ester, particularly a salt-type phosphoric acid ester, may be added to calcium carbonate and kneaded or pulverized as described above.
　炭酸カルシウムの含水ケーキを用いる表面処理でも、乾式法と同様の条件を採用することができるが、好ましくは処理時の温度を２０～１５０℃、特に４０～９８℃程度とする。このことによって、表面処理剤の不均一吸着や突沸のリスクを低減することが可能となる。 Although the same conditions as the dry method can be used for the surface treatment using the hydrated cake of calcium carbonate, the temperature during treatment is preferably 20 to 150°C, particularly about 40 to 98°C. This makes it possible to reduce the risk of non-uniform adsorption and bumping of the surface treatment agent.
　本発明の樹脂組成物において、無機物質粉末は上記のようなリン酸エステルを含有する表面処理剤で表面処理された炭酸カルシウムであるが、さらにこれら以外の無機物質粉末を含んでも良い。例としてカルシウム、マグネシウム、アルミニウム、チタン、鉄、亜鉛等の炭酸塩、硫酸塩、珪酸塩、リン酸塩、ホウ酸塩、酸化物、若しくはこれらの水和物の粉末状のものが挙げられ、具体的には、例えば、非表面処理炭酸カルシウム、炭酸マグネシウム、酸化亜鉛、酸化チタン、シリカ、アルミナ、クレー、タルク、カオリン、水酸化アルミニウム、水酸化マグネシウム、ケイ酸アルミニウム、ケイ酸マグネシウム、ケイ酸カルシウム、硫酸アルミニウム、硫酸マグネシウム、硫酸カルシウム、リン酸マグネシウム、硫酸バリウム、珪砂、カーボンブラック、ゼオライト、モリブデン、珪藻土、セリサイト、シラス、亜硫酸カルシウム、硫酸ナトリウム、チタン酸カリウム、ベントナイト、ウォラストナイト、ドロマイト、黒鉛等が挙げられる。これらは合成のものであっても天然鉱物由来のものであっても良く、また、これらは単独又は２種類以上併用して含有されても良い。しかしながら熱可塑性樹脂中への分散性や樹脂組成物からの溶出等を考慮すると、本発明の樹脂組成物における無機物質粉末は、好ましくは９０質量％以上、より好ましくは９５質量％以上、特に好ましくは不可避的不純物を除く実質的に全量が、上記の表面処理炭酸カルシウム粉末から成るのが良い。 In the resin composition of the present invention, the inorganic substance powder is calcium carbonate surface-treated with a surface treatment agent containing a phosphate ester as described above, but may further contain inorganic substance powders other than these. Examples include powdery carbonates, sulfates, silicates, phosphates, borates, oxides, or hydrates thereof of calcium, magnesium, aluminum, titanium, iron, zinc, etc. Specifically, for example, non-surface-treated calcium carbonate, magnesium carbonate, zinc oxide, titanium oxide, silica, alumina, clay, talc, kaolin, aluminum hydroxide, magnesium hydroxide, aluminum silicate, magnesium silicate, silicic acid Calcium, aluminum sulfate, magnesium sulfate, calcium sulfate, magnesium phosphate, barium sulfate, silica sand, carbon black, zeolite, molybdenum, diatomaceous earth, sericite, shirasu, calcium sulfite, sodium sulfate, potassium titanate, bentonite, wollastonite, Dolomite, graphite and the like can be mentioned. These may be synthetic or derived from natural minerals, and may be contained singly or in combination of two or more. However, considering the dispersibility in the thermoplastic resin, the elution from the resin composition, etc., the inorganic substance powder in the resin composition of the present invention is preferably 90% by mass or more, more preferably 95% by mass or more, and particularly preferably 95% by mass or more. is substantially entirely composed of the above-mentioned surface-treated calcium carbonate powder, excluding unavoidable impurities.
≪樹脂組成物≫
　本発明の樹脂組成物においては、上記した熱可塑性樹脂と無機物質粉末とが、５０：５０～１０：９０の質量比で含有される。無機物質粉末の含有量が少ないと、樹脂組成物の質感や強度等の物性が得難く、多すぎると混練や成形加工が困難となり、柔軟性も不十分となるためである。熱可塑性樹脂と無機物質粉末との合計質量に占める無機物質粉末の比率は、好ましくは５２質量％以上、より好ましくは５５質量％以上である。同比率の上限値に関しては、好ましくは８０質量％以下、より好ましくは７５質量％以下、特に好ましくは７０質量％以下とする。 <<Resin composition>>
The resin composition of the present invention contains the thermoplastic resin and the inorganic powder in a mass ratio of 50:50 to 10:90. If the content of the inorganic substance powder is too small, it is difficult to obtain physical properties such as texture and strength of the resin composition. The ratio of the inorganic substance powder to the total mass of the thermoplastic resin and the inorganic substance powder is preferably 52% by mass or more, more preferably 55% by mass or more. The upper limit of the ratio is preferably 80% by mass or less, more preferably 75% by mass or less, and particularly preferably 70% by mass or less.
　＜その他の添加剤＞
　本発明に係る樹脂組成物には、必要に応じて、補助剤としてその他の添加剤を配合することも可能である。その他の添加剤としては、例えば、色剤、滑剤、カップリング剤、流動性改良材（流動性調整剤）、架橋剤、分散剤、酸化防止剤、紫外線吸収剤、難燃剤、安定剤、帯電防止剤、発泡剤、可塑剤等を配合しても良い。これらの添加剤は、単独で用いても良く、２種以上を併用しても良い。また、これらは、後述の混練工程において配合しても良く、混練工程の前にあらかじめ原料成分中に配合していても良い。 <Other additives>
The resin composition according to the present invention may optionally contain other additives as auxiliary agents. Other additives include, for example, colorants, lubricants, coupling agents, fluidity modifiers (fluidity modifiers), cross-linking agents, dispersants, antioxidants, ultraviolet absorbers, flame retardants, stabilizers, and electrifying agents. Inhibitors, foaming agents, plasticizers, etc. may be blended. These additives may be used alone or in combination of two or more. Moreover, these may be blended in the kneading step described later, or may be blended in the raw material components in advance before the kneading step.
　本発明に係る樹脂組成物において、これらのその他の添加剤の添加量は、所望の物性及び加工性を阻害しない限り特に限定されるものではないが、上記樹脂組成物全体の質量を１００％とした場合に、これらその他の添加剤はそれぞれ０～１０質量％程度、特に０．０４～５質量％程度の割合で、かつ当該その他の添加剤全体で１０質量％以下となる割合で配合されることが望まれる。例えば、樹脂組成物全１００質量％中には、１０～４５質量％、特に２０～２５質量％の熱可塑性樹脂；９０～４５質量％、特に７５～５５質量％の表面改質炭酸カルシウム；及び０～１０質量％、特に０．０４～５質量％の上記添加剤が含有されていても良い。 In the resin composition according to the present invention, the amount of these other additives added is not particularly limited as long as it does not impede the desired physical properties and processability, but the mass of the entire resin composition is 100%. In this case, each of these other additives is blended in a ratio of about 0 to 10% by mass, particularly about 0.04 to 5% by mass, and the total amount of the other additives is 10% by mass or less. is desired. For example, in the total 100% by mass of the resin composition, 10 to 45% by mass, especially 20 to 25% by mass of thermoplastic resin; 90 to 45% by mass, especially 75 to 55% by mass of surface-modified calcium carbonate; 0 to 10% by weight, in particular 0.04 to 5% by weight of the above additives may be contained.
　以下に、これら添加剤の内、重要と考えられるものについて例を挙げて説明するが、これらに限られるものではない。 Among these additives, the ones that are considered important will be explained below with examples, but they are not limited to these.
　可塑剤としては、例えば、クエン酸トリエチル、クエン酸アセチル・トリエチル、フタル酸ジブチル、フタル酸ジアリール、フタル酸ジメチル、フタル酸ジエチル、フタル酸ジ－２－メトキシエチル、酒石酸ジブチル、ｏ－ベンゾイル安息香酸エステル、ジアセチン、エポキシ化大豆油等が挙げられる。これら可塑剤は通常、熱可塑性樹脂に対して数質量％程度配合されるが、その量はこれら範囲に限定されず、樹脂組成物の用途によってはエポキシ化大豆油等を２０～５０質量部程度配合することも可能である。しかしながら本発明の樹脂組成物においては、その配合量は熱可塑性樹脂１００質量部に対し０．５～１０質量部、特に１～５質量部程度とするのが好ましい。 Examples of plasticizers include triethyl citrate, acetyl-triethyl citrate, dibutyl phthalate, diaryl phthalate, dimethyl phthalate, diethyl phthalate, di-2-methoxyethyl phthalate, dibutyl tartrate, and o-benzoylbenzoic acid. Ester, diacetin, epoxidized soybean oil and the like. These plasticizers are usually blended in an amount of about several percent by mass with respect to the thermoplastic resin, but the amount is not limited to these ranges, and depending on the application of the resin composition, epoxidized soybean oil or the like is added in an amount of about 20 to 50 parts by mass. Blending is also possible. However, in the resin composition of the present invention, the blending amount is preferably about 0.5 to 10 parts by weight, particularly about 1 to 5 parts by weight, per 100 parts by weight of the thermoplastic resin.
　色剤としては、公知の有機顔料又は無機顔料あるいは染料の何れをも用いることができる。具体的には、アゾ系、アンスラキノン系、フタロシアニン系、キナクリドン系、イソインドリノン系、ジオオサジン系、ペリノン系、キノフタロン系、ペリレン系顔料などの有機顔料や群青、酸化チタン、チタンイエロー、酸化鉄（弁柄）、酸化クロム、亜鉛華、カーボンブラックなどの無機顔料が挙げられる。 Any of known organic pigments, inorganic pigments, or dyes can be used as the coloring agent. Specifically, organic pigments such as azo-based, anthraquinone-based, phthalocyanine-based, quinacridone-based, isoindolinone-based, diosazine-based, perinone-based, quinophthalone-based, and perylene-based pigments, ultramarine blue, titanium oxide, titanium yellow, and iron oxide. (Rouge), chromium oxide, zinc white, carbon black and other inorganic pigments.
　滑剤としては、例えば、ステアリン酸、ヒドロキシステアリン酸、複合型ステアリン酸、オレイン酸等の脂肪酸系滑剤；脂肪族アルコール系滑剤；ステアロアミド、オキシステアロアミド、オレイルアミド、エルシルアミド、リシノールアミド、ベヘンアミド、メチロールアミド、メチレンビスステアロアミド、メチレンビスステアロベヘンアミド、高級脂肪酸のビスアミド酸、複合型アミド等の脂肪族アマイド系滑剤；ステアリン酸－ｎ－ブチル、ヒドロキシステアリン酸メチル、多価アルコール脂肪酸エステル、飽和脂肪酸エステル、エステル系ワックス等の脂肪族エステル系滑剤；脂肪酸金属石鹸系滑剤、例えばジンクステアレートやステアリン酸マグネシウム等を挙げることができる。 Examples of lubricants include fatty acid-based lubricants such as stearic acid, hydroxystearic acid, complex stearic acid, and oleic acid; fatty alcohol-based lubricants; stearamide, oxystearamide, oleylamide, erucylamide, ricinolamide, behenamide, and methylol. Aliphatic amide-based lubricants such as amides, methylenebisstearamide, methylenebisstearobehenamide, higher fatty acid bisamic acids, complex amides; n-butyl stearate, methyl hydroxystearate, polyhydric alcohol fatty acid esters, Fatty acid ester-based lubricants such as saturated fatty acid esters and ester-based waxes; and fatty acid metal soap-based lubricants such as zinc stearate and magnesium stearate.
　酸化防止剤としては、リン系酸化防止剤、フェノール系酸化防止剤、ペンタエリスリトール系酸化防止剤が使用できる。リン系、より具体的には亜リン酸エステル、リン酸エステル等のリン系酸化防止剤が好ましく用いられる。亜リン酸エステルとしては、例えば、トリフェニルホスファイト、トリスノニルフェニルホスファイト、トリス（２，４－ジ－ｔ－ブチルフェニル）ホスファイト、等の亜リン酸のトリエステル、ジエステル、モノエステル等が挙げられる。 As antioxidants, phosphorus-based antioxidants, phenol-based antioxidants, and pentaerythritol-based antioxidants can be used. Phosphorus-based antioxidants, more specifically phosphorus-based antioxidants such as phosphites and phosphates, are preferably used. Examples of phosphites include triphenyl phosphite, trisnonylphenyl phosphite, tris(2,4-di-t-butylphenyl) phosphite, and other phosphorous acid triesters, diesters, and monoesters. is mentioned.
　リン酸エステルとしては、トリメチルホスフェート、トリエチルホスフェート、トリブチルホスフェート、トリオクチルホスフェート、トリフェニルホスフェート、トリクレジルホスフェート、トリス（ノニルフェニル）ホスフェート、２－エチルフェニルジフェニルホスフェート等が挙げられる。これらリン系酸化防止剤は単独で用いても良く、二種以上を組み合わせて用いても良い。 Phosphate esters include trimethyl phosphate, triethyl phosphate, tributyl phosphate, trioctyl phosphate, triphenyl phosphate, tricresyl phosphate, tris(nonylphenyl) phosphate, 2-ethylphenyl diphenyl phosphate, and the like. These phosphorus-based antioxidants may be used alone, or two or more of them may be used in combination.
　フェノール系の酸化防止剤としては、α－トコフェロール、ブチルヒドロキシトルエン、シナピルアルコール、ビタミンＥ、ｎ－オクタデシル－３－（３，５－ジ－ｔ－ブチル－４－ヒドロキシフェニル）プロピオネイト、２－ｔ－ブチル－６－（３'－ｔ－ブチル－５'－メチル－２'－ヒドロキシベンジル）－４－メチルフェニルアクリレート、２，６－ジ－ｔ－ブチル－４－（Ｎ，Ｎ－ジメチルアミノメチル）フェノール、３，５－ジ－ｔ－ブチル－４－ヒドロキシベンジルホスホネイトジエチルエステル、及びテトラキス［３－（３，５－ジ－ｔ－ブチル－４－ヒドロキシフェニル）プロピオニルオキシメチル］メタン等が例示され、これらは単独で又は２種以上を組合せて使用することができる。 Phenolic antioxidants include α-tocopherol, butylhydroxytoluene, sinapyl alcohol, vitamin E, n-octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, 2- t-butyl-6-(3'-t-butyl-5'-methyl-2'-hydroxybenzyl)-4-methylphenyl acrylate, 2,6-di-t-butyl-4-(N,N-dimethyl aminomethyl)phenol, 3,5-di-t-butyl-4-hydroxybenzylphosphonate diethyl ester, and tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionyloxymethyl]methane etc., and these can be used alone or in combination of two or more.
　難燃剤としては、特に限定されないが、例えば、ハロゲン系難燃剤や、あるいはリン系難燃剤や金属水和物などの非リン系ハロゲン系難燃剤を用いることができる。ハロゲン系難燃剤としては、具体的には例えば、ハロゲン化ビスフェニルアルカン、ハロゲン化ビスフェニルエーテル、ハロゲン化ビスフェニルチオエーテル、ハロゲン化ビスフェニルスルフォンなどのハロゲン化ビスフェノール系化合物、臭素化ビスフェノールＡ、臭素化ビスフェノールＳ、塩素化ビスフェノールＡ、塩素化ビスフェノールＳなどのビスフェノール－ビス（アルキルエーテル）系化合物等が、またリン系難燃剤としては、トリス（ジエチルホスフィン酸）アルミニウム、ビスフェノールＡビス（ジフェニルホスフェート）、リン酸トリアリールイソプロピル化物、クレジルジ２、６－キシレニルホスフェート、芳香族縮合リン酸エステル等が、金属水和物としては、例えば、アルミニウム三水和物、水酸化マグネシウム又はこれらの組み合わせ等がそれぞれ例示でき、これらは単独で又は２種以上を組合せて使用することができる。難燃助剤として働き、より効果的に難燃効果を向上させることが可能となる。さらに、例えば、三酸化アンチモン、五酸化アンチモン等の酸化アンチモン、酸化亜鉛、酸化鉄、酸化アルミニウム、酸化モリブデン、酸化チタン、酸化カルシウム、酸化マグネシウム等を難燃助剤として併用することも可能である。 The flame retardant is not particularly limited, but for example, halogen flame retardants or non-phosphorus halogen flame retardants such as phosphorus flame retardants and metal hydrates can be used. Specific examples of halogen flame retardants include halogenated bisphenol compounds such as halogenated bisphenylalkanes, halogenated bisphenyl ethers, halogenated bisphenylthioethers, and halogenated bisphenylsulfones, brominated bisphenol A, bromine Bisphenol-bis(alkyl ether) compounds such as bisphenol S, chlorinated bisphenol A, and chlorinated bisphenol S, and phosphorus-based flame retardants such as aluminum tris(diethylphosphinate) and bisphenol A bis(diphenyl phosphate). , triaryl isopropyl phosphate, cresyl di-2,6-xylenyl phosphate, aromatic condensed phosphate esters, etc., and metal hydrates such as aluminum trihydrate, magnesium hydroxide, combinations thereof, etc. can be exemplified, respectively, and these can be used alone or in combination of two or more. It works as a flame retardant assistant, and can improve the flame retardant effect more effectively. Furthermore, for example, antimony oxides such as antimony trioxide and antimony pentoxide, zinc oxide, iron oxide, aluminum oxide, molybdenum oxide, titanium oxide, calcium oxide, magnesium oxide, etc. can be used in combination as flame retardant aids. .
　発泡剤は、溶融混練機内で溶融状態にされている樹脂組成物に混合、又は圧入し、固体から気体、液体から気体に相変化するもの、又は気体そのものであり、樹脂組成物の空隙率（発泡倍率）を制御するために使用される。発泡剤は、常温で液体のものは樹脂温度によって気体に相変化して溶融樹脂に溶解し、常温で気体のものは相変化せずそのまま溶融樹脂に溶解する。溶融樹脂に分散溶解した発泡剤は、溶融樹脂を押出ダイからシート状に押出した際に、圧力が開放されるのでシート内部で膨張し、シート内に多数の微細な独立気泡を形成して発泡シートが得られる。発泡剤は、副次的に原料樹脂組成物の溶融粘度を下げる可塑剤として作用し、原料樹脂組成物を可塑化状態にするための温度を低くする。 The foaming agent is mixed or injected into the resin composition that is in a molten state in the melt kneader and undergoes a phase change from solid to gas, liquid to gas, or gas itself, and the porosity of the resin composition ( foaming ratio). A foaming agent that is liquid at room temperature undergoes a phase change to a gas depending on the resin temperature and dissolves in the molten resin, while a foaming agent that is gas at room temperature does not undergo a phase change and dissolves in the molten resin as it is. The foaming agent dispersed and dissolved in the molten resin expands inside the sheet as the pressure is released when the molten resin is extruded into a sheet from an extrusion die, forming a large number of fine closed cells within the sheet and foaming. A sheet is obtained. The foaming agent secondarily acts as a plasticizer that lowers the melt viscosity of the raw material resin composition, and lowers the temperature for making the raw resin composition plasticized.
　発泡剤としては、例えば、プロパン、ブタン、ペンタン、ヘキサン、ヘプタンなどの脂肪族炭化水素類；シクロブタン、シクロペンタン、シクロヘキサンなどの脂環式炭化水素類；クロロジフルオロメタン、ジフロオロメタン、トリフルオロメタン、トリクロロフルオロメタン、ジクロロメタン、ジクロロフルオロメタン、ジクロロジフルオロメタン、クロロメタン、クロロエタン、ジクロロトリフルオロエタン、ジクロロペンタフルオロエタン、テトラフルオロエタン、ジフルオロエタン、ペンタフルオロエタン、トリフルオロエタン、ジクロロテトラフルオロエタン、トリクロロトリフルオロエタン、テトラクロロジフルオロエタン、パーフルオロシクロブタンなどのハロゲン化炭化水素類；二酸化炭素、チッ素、空気などの無機ガス；水などが挙げられる。 Examples of blowing agents include aliphatic hydrocarbons such as propane, butane, pentane, hexane and heptane; alicyclic hydrocarbons such as cyclobutane, cyclopentane and cyclohexane; chlorodifluoromethane, difluoromethane, trifluoromethane, trichlorofluoromethane; Methane, dichloromethane, dichlorofluoromethane, dichlorodifluoromethane, chloromethane, chloroethane, dichlorotrifluoroethane, dichloropentafluoroethane, tetrafluoroethane, difluoroethane, pentafluoroethane, trifluoroethane, dichlorotetrafluoroethane, trichlorotrifluoroethane , tetrachlorodifluoroethane and perfluorocyclobutane; inorganic gases such as carbon dioxide, nitrogen and air; and water.
　発泡剤としては、さらに、例えば、キャリアレジンに発泡剤の有効成分が含まれるものを好ましく用いる事ができる。キャリアレジンとしては、結晶性オレフィン樹脂等が挙げられる。これらの内、結晶性ポリプロピレン樹脂が好ましい。また、有効成分としては、炭酸水素塩等が挙げられる。これらの内、炭酸水素塩が好ましい。結晶性ポリプロピレン樹脂をキャリアレジンとし、炭酸水素塩を熱分解型発泡剤として含む発泡剤コンセントレートであることが好ましい。 As the foaming agent, for example, a carrier resin containing an active ingredient of the foaming agent can be preferably used. Examples of carrier resins include crystalline olefin resins. Among these, crystalline polypropylene resins are preferred. Moreover, hydrogen carbonate etc. are mentioned as an active ingredient. Among these, hydrogen carbonate is preferred. A blowing agent concentrate containing a crystalline polypropylene resin as a carrier resin and a hydrogen carbonate as a thermally decomposable blowing agent is preferred.
　成形工程において発泡剤に含まれる発泡剤の含有量は、熱可塑性樹脂及び無機物質粉末の量等に応じて適宜設定することができ、樹脂組成物の全質量に対して０．０４～５．００質量％の範囲とすることが好ましい。 The content of the foaming agent contained in the foaming agent in the molding process can be appropriately set according to the amounts of the thermoplastic resin and the inorganic substance powder, etc., and is 0.04 to 5.0% relative to the total mass of the resin composition. 00% by mass is preferable.
　流動性調整剤としても、種々の慣用のものを使用することができる。例としてジアルキルパーオキサイド等の過酸化物、例えば１，４－ビス［（ｔ－ブチルパーオキシ）イソプロピル］ベンゼン等が挙げられるが、これらに限定されない。使用する熱可塑性樹脂の種類によっては、これら過酸化物は架橋剤としても作用する。特に上記熱可塑性樹脂成分がジエン由来の構成単位を有する場合、上記過酸化物の作用で共重合体の一部が架橋し、熱可塑性樹脂組成物の物性や加工性を制御する上での一助となり得る。過酸化物の添加量に特に制限はないが、熱可塑性樹脂組成物の全質量に対して０．０４～２．００質量％、特に０．０５～０．５０質量％程度の範囲とすることが好ましい。 Various commonly used fluidity modifiers can also be used. Examples include, but are not limited to, peroxides such as dialkyl peroxides such as 1,4-bis[(t-butylperoxy)isopropyl]benzene and the like. Depending on the type of thermoplastic used, these peroxides may also act as crosslinkers. In particular, when the thermoplastic resin component has diene-derived structural units, part of the copolymer is crosslinked by the action of the peroxide, which helps control the physical properties and workability of the thermoplastic resin composition. can be. The amount of the peroxide to be added is not particularly limited, but should be in the range of 0.04 to 2.00% by mass, particularly 0.05 to 0.50% by mass, based on the total mass of the thermoplastic resin composition. is preferred.
≪樹脂組成物の調製方法≫
　本発明の樹脂組成物を調製する方法としては、通常の方法を使用することができ、成形方法（押出成形、射出成形、真空成形等）に応じて適宜設定することが可能である。例えば、熱可塑性樹脂と無機物質粉末とを混練溶融することにより調製できる。溶融混練は、各成分を均一に分散させる傍ら、高い剪断応力を作用させて混練することが好ましい。混合装置としても、一般的な押出機、ニーダー、バンバリーミキサー等種々のものを用いることができるが、例えば二軸混練機で混練することが好ましい。調製した樹脂組成物は例えば、所望の形状及びサイズのペレットとし、種々の成形品の製造に用いることができる。また、目的とする成形品の形状によっては、各原料を混練して熱可塑性樹脂組成物を調製すると同時に成形することも可能である。例えば、各種原料を二軸押出機で混練し、シート状物を押出成形することにより、シート形状の成形品を製造することができる。 <<Method for preparing resin composition>>
As a method for preparing the resin composition of the present invention, a conventional method can be used, and the method can be appropriately set according to the molding method (extrusion molding, injection molding, vacuum molding, etc.). For example, it can be prepared by kneading and melting a thermoplastic resin and an inorganic powder. Melt-kneading is preferably carried out by applying a high shear stress while dispersing each component uniformly. As a mixing device, various devices such as a general extruder, a kneader, and a Banbury mixer can be used. The prepared resin composition can be made into pellets of desired shape and size, for example, and used to produce various molded articles. Depending on the desired shape of the molded product, it is also possible to knead each raw material to prepare a thermoplastic resin composition and to mold the composition at the same time. For example, a sheet-shaped molded article can be produced by kneading various raw materials with a twin-screw extruder and extruding a sheet-shaped material.
≪成形品≫
　本発明はまた、上記した樹脂組成物からなる成形品を包含する。本発明の樹脂組成物は、熱可塑性樹脂中に炭酸カルシウムが高充填されているにも拘らず、成形性が良好で、機械的強度等の物性も優れる。そのため、様々な用途に有用な各種形状の成形品へと成形することができる。本発明の樹脂組成物はまた、酸性条件下での溶出量が少ないため、従来の無機物質粉末充填樹脂組成物とは異なり、食品と直接触れる成形品にも使用することができる。しかもその際に、ポリオレフィン等の樹脂層を積層した、２層～３層構造とする必要がない。そのため本発明の成形品は、特に食品包装容器及び食器用に好適である。本発明はさらに、上記の樹脂組成物からなる食品包装容器を包含する。 ≪Molded product≫
The present invention also includes a molded article made of the resin composition described above. The resin composition of the present invention has good moldability and excellent physical properties such as mechanical strength even though the thermoplastic resin is highly filled with calcium carbonate. Therefore, it can be molded into molded articles of various shapes that are useful for various purposes. Also, since the resin composition of the present invention has a small amount of elution under acidic conditions, it can be used for moldings that come into direct contact with food, unlike conventional inorganic powder-filled resin compositions. Moreover, at that time, it is not necessary to form a two-layer or three-layer structure in which resin layers such as polyolefin are laminated. Therefore, the molded article of the present invention is particularly suitable for food packaging containers and tableware. The present invention further includes a food packaging container comprising the above resin composition.
≪食品包装容器≫
　本発明に係る食品包装容器の形状等は特に限定されるものではなく、弁当容器、コップ、皿、ボウル、茶碗、さらにはスプーン、フォーク、箸等、各種の形態及びサイズのものであって良い。例えば、肉厚４０μｍ～１０ｍｍ、より好ましくは肉厚１００μｍ～５ｍｍである容器体としても良い。この範囲内の肉厚であれば、熱可塑性樹脂中に炭酸カルシウムが均一に分散されていることにより、良好な成形性、加工性が得られ、偏肉の無い均質で欠陥のない容器体を形成することができる。 ≪Food packaging container≫
The shape and the like of the food packaging container according to the present invention are not particularly limited, and may be of various shapes and sizes, such as lunch boxes, cups, plates, bowls, bowls, spoons, forks, and chopsticks. . For example, the container may have a thickness of 40 μm to 10 mm, more preferably 100 μm to 5 mm. If the wall thickness is within this range, the calcium carbonate is uniformly dispersed in the thermoplastic resin, so that good moldability and workability can be obtained, and a homogeneous and defect-free container without uneven wall thickness can be obtained. can be formed.
　＜成形体の製造方法＞
　本発明の成形品の製造方法としては、所望の形状に成形できるものであれば特に限定されず、従来公知の押出成形、射出成形、真空成形、ブロー成形、カレンダー成形等の何れの方法によっても成形加工可能である。上記のように本発明の樹脂組成物は、食品包装容器等に成形するに当たって他樹脂層との２層～３層構造とする必要がないので、種々の形状の成形体に慣用の方法で成形することができる。さらにまた、本発明に係る樹脂組成物が発泡剤を含有し、発泡体である態様の成形品を得る場合においても、所望の形状に成形できるものであれば発泡体の成形方法として従来公知の、例えば、射出発泡，押出発泡，発泡ブロー等の液相発泡法、あるいは、例えば、ビーズ発泡，バッチ発泡，プレス発泡，常圧二次発泡等の固相発泡法の何れを用いることも可能である。前記した、結晶性ポリプロピレンをキャリアレジンとし、炭酸水素塩を熱分解型発泡剤として含む熱可塑性組成物の一態様においては、射出発泡法及び押出発泡法が望ましく用いられ得る。 <Method for manufacturing molded body>
The method for producing the molded article of the present invention is not particularly limited as long as it can be molded into a desired shape, and any of conventionally known methods such as extrusion molding, injection molding, vacuum molding, blow molding and calendar molding can be used. Can be molded. As described above, the resin composition of the present invention does not need to have a 2- to 3-layer structure with other resin layers when molded into a food packaging container or the like. can do. Furthermore, even in the case where the resin composition according to the present invention contains a foaming agent and a molded product in the form of a foam is obtained, as long as it can be molded into a desired shape, conventionally known foam molding methods can be used. For example, liquid phase foaming methods such as injection foaming, extrusion foaming and foam blowing, or solid phase foaming methods such as bead foaming, batch foaming, press foaming and normal pressure secondary foaming can be used. be. In one aspect of the thermoplastic composition containing crystalline polypropylene as a carrier resin and a hydrogen carbonate as a thermally decomposable foaming agent, an injection foaming method and an extrusion foaming method can be desirably used.
　なお、射出成形、押出成形等における成形温度としては、その成形方法や使用する熱可塑性樹脂の種類等によってもある程度異なるため、一概には規定できるものではないが、好ましくは熱可塑性樹脂成分の融点＋５～１００℃程度、特に＋１０～５０℃程度の温度、例えば、１８０～２６０℃、より好ましくは１９０～２３０℃とすることができる。こうした温度であれば、本発明に係る樹脂組成物が、良好なドローダウン特性、延展性を持って、かつ組成物が局部的にも変性を生じることなく所定形状に成形できる。 The molding temperature in injection molding, extrusion molding, etc., varies to some extent depending on the molding method and the type of thermoplastic resin used, so it cannot be defined unconditionally, but the melting point of the thermoplastic resin component is preferable. The temperature can be about +5 to 100°C, particularly about +10 to 50°C, for example, 180 to 260°C, more preferably 190 to 230°C. At such a temperature, the resin composition according to the present invention has good drawdown properties and spreadability, and can be molded into a predetermined shape without locally modifying the composition.
　以下、本発明を実施例に基づきより具体的に説明する。なお、これらの実施例は、本明細書に開示され、また添付の請求の範囲に記載された、本発明の概念及び範囲の理解を、より容易なものとする上で、特定の態様及び実施形態の例示の目的のためにのみ記載するのであって、本発明はこれらの実施例に何ら限定されるものではない。 Hereinafter, the present invention will be described more specifically based on examples. It should be noted that these Examples are intended to provide specific aspects and implementations in order to facilitate an understanding of the concept and scope of the present invention disclosed herein and recited in the appended claims. The present invention is in no way limited to these examples, which are provided for illustrative purposes only.
［実施例１］
　平均粒子径２．２μｍ（空気透過法による）、比表面積１０，０００ｃｍ２／ｇの重質炭酸カルシウム（備北粉化工業株式会社製のソフトン（商品名）１０００）１００質量部を、ポリオキシエチレンラウリルエーテルリン酸（東邦化学工業株式会社製フォスファノール（登録商標）ＭＬ－２２０：Ｃ１２Ｈ２５Ｏ（Ｃ２Ｈ４Ｏ）２－Ｐ（＝Ｏ）（ＯＨ）２と［Ｃ１２Ｈ２５Ｏ（Ｃ２Ｈ４Ｏ）２］２Ｐ（＝Ｏ）ＯＨとの混合物、第１酸価１４０～１６０）３質量部と共に、ヘンシェルミキサーにて、温度１２０℃、回転数１２００ｒｐｍで３０分間攪拌し、表面処理した。 [Example 1]
100 parts by mass of heavy calcium carbonate (Softon (trade name) 1000 manufactured by Bihoku Funka Kogyo Co., Ltd.) having an average particle size of 2.2 μm (according to the air permeation method) and a specific surface area of 10,000 cm 2 /g, is mixed with polyoxyethylene. Lauryl ether phosphate (Toho Chemical Industry Co., Ltd. Phosphanol (registered trademark) ML-220: C 12 H 25 O (C 2 H 4 O) 2 —P (=O) (OH) 2 and [C 12 H A mixture of 25 O(C 2 H 4 O) 2 ] 2 P(=O)OH and 3 parts by mass of a first acid value of 140 to 160) were mixed in a Henschel mixer at a temperature of 120°C and a rotation speed of 1200 rpm for 30 minutes. Stirred and surface treated.
　上記で得られた表面処理炭酸カルシウム６０質量部と、ポリプロピレン単独重合体（株式会社プライムポリマー製のプライムポリプロ(登録商標）Ｅ１１１Ｇ、融点１６０℃）４０質量部とを、ステアリン酸マグネシウム滑剤０．５質量部と共に、株式会社パーカーコーポレーション製同方向回転二軸混練押出機ＨＫ－２５Ｄ（φ２５ｍｍ、Ｌ／Ｄ＝４１）に投入し、シリンダー温度１９０～２００℃でストランド押出後、冷却、カットすることでペレット化した。 60 parts by mass of the surface-treated calcium carbonate obtained above and 40 parts by mass of a polypropylene homopolymer (Prime Polypro (registered trademark) E111G manufactured by Prime Polymer Co., Ltd., melting point 160 ° C.) were mixed with 0.5 parts of magnesium stearate lubricant. Together with the mass part, it is put into a co-rotating twin-screw kneading extruder HK-25D (φ25 mm, L / D = 41) manufactured by Parker Corporation, extruded at a cylinder temperature of 190 to 200 ° C., cooled and cut. pelleted.
　上記のようにして作製したペレットをそれぞれ、株式会社東洋精機製作所製のラボプラストミル一軸Ｔダイ押出成形装置（φ２０ｍｍ、Ｌ／Ｄ＝２５）により、２２０℃で押出し、厚さ０．３ｍｍのシートに成形した。得られたシートについて、下記の試験方法によって強度及び伸び等の物性を評価した。試験結果を、表１に示す。
（酢酸溶出試験）
　上記シートから３０ｍｍ×３０ｍｍの短冊状試験片を切り出し、これを４％酢酸４５ｍｌに（接触面積１ｃｍ２当たりの酢酸量:約２ｍｌ）、６０℃で３０分間浸漬した。浸漬後の試料を乾燥させて質量を測定し、浸漬前後の質量変化から、酢酸溶出量（質量％）を算出した。なお、試験はｎ＝３にて行い、平均値を採用した。
（引張強度、伸び）
　引張強度、伸びは、上記シートより切り出したダンベル形状の試料を用い、ＪＩＳ　Ｋ　７１６１－２：２０１４に準拠して、２３℃、５０％ＲＨの条件下で、オートグラフＡＧ－１００ｋＮＸｐｌｕｓ（株式会社島津製作所）を用いて測定した。引張方向は押出方向とし、引張速度は５０ｍｍ／分とした。
（延伸特性）
　上記シートを１００℃で押出方向に４倍まで延伸し、何倍に延伸した際に破断するかを観察した。 Each of the pellets prepared as described above is extruded at 220 ° C. by a Labo Plastomill uniaxial T-die extrusion molding device (φ 20 mm, L / D = 25) manufactured by Toyo Seiki Seisakusho Co., Ltd. to form a sheet with a thickness of 0.3 mm. molded into Physical properties such as strength and elongation of the obtained sheet were evaluated by the following test methods. Table 1 shows the test results.
(Acetic acid elution test)
A strip-shaped test piece of 30 mm×30 mm was cut out from the above sheet and immersed in 45 ml of 4% acetic acid (the amount of acetic acid per 1 cm 2 of contact area: about 2 ml) at 60° C. for 30 minutes. After the immersion, the sample was dried and weighed, and the amount of acetic acid eluted (% by mass) was calculated from the change in mass before and after the immersion. The test was conducted with n=3, and the average value was adopted.
(tensile strength, elongation)
Tensile strength and elongation were measured using a dumbbell-shaped sample cut out from the above sheet, in accordance with JIS K 7161-2: 2014, under conditions of 23 ° C. and 50% RH, Autograph AG-100kNXplus (Shimadzu Corporation Seisakusho) was used. The tensile direction was the extrusion direction, and the tensile speed was 50 mm/min.
(Stretching properties)
The sheet was stretched up to 4 times in the extrusion direction at 100° C., and it was observed how many times the sheet would be broken.
［比較例１］
　無機物質粉末として未処理のソフトン１０００を使用し、実施例１と同様の操作を行った。試験結果を、表１に示す。 [Comparative Example 1]
The same operation as in Example 1 was performed using untreated SOFTON 1000 as the inorganic powder. Table 1 shows the test results.
［実施例２］
　ポリオキシエチレンラウリルエーテルリン酸の代わりにポリオキシエチレンラウリルフェノールリン酸（芳香族ＥＯリン酸エステル、東邦化学工業株式会社製フォスファノール（登録商標）ＬＦ－２００：Ｃ１２Ｈ２５Ｃ４Ｈ４Ｏ（Ｃ２Ｈ４Ｏ）２－Ｐ（＝Ｏ）（ＯＨ）２と［Ｃ１２Ｈ２５ＯＣ４Ｈ４（Ｃ２Ｈ４Ｏ）２］２Ｐ（＝Ｏ）ＯＨとの混合物、第１酸価９５～１１５）を用い、実施例１と同様の操作を行った。試験結果を、表１に示す。 [Example 2]
Polyoxyethylene lauryl phenol phosphate (aromatic EO phosphate ester, manufactured by Toho Chemical Industry Co., Ltd. Phosphanol (registered trademark) LF-200: C 12 H 25 C 4 H 4 instead of polyoxyethylene lauryl ether phosphate A mixture of O(C 2 H 4 O) 2 -P(=O)(OH) 2 and [C 12 H 25 OC 4 H 4 (C 2 H 4 O) 2 ] 2 P(=O) OH, The same operation as in Example 1 was carried out using a monoacid value of 95 to 115). Table 1 shows the test results.
［実施例３］
　ポリオキシエチレンラウリルエーテルリン酸の代わりにラウリルリン酸（東邦化学工業株式会社製フォスファノール（登録商標）ＭＬ－２００：Ｃ１２Ｈ２５Ｏ－Ｐ（＝Ｏ）（ＯＨ）２と（Ｃ１２Ｈ２５Ｏ）２Ｐ（＝Ｏ）ＯＨとの混合物、第１酸価１９０～２１０）を用い、実施例１と同様の操作を行った。試験結果を、表１に示す。 [Example 3]
Lauryl phosphoric acid (Toho Chemical Industry Co., Ltd. Phosphanol (registered trademark) ML-200: C 12 H 25 OP (= O) (OH) 2 and (C 12 The same procedure as in Example 1 was carried out using a mixture with H 25 O) 2 P(=O)OH, primary acid value 190-210). Table 1 shows the test results.
［実施例４］
　ソフトン１０００を精製水中に分散させ（濃度１００ｇ／Ｌ）、スラリーを作製した。このスラリーに、長鎖不飽和脂肪族炭化水素鎖とエチレンオキシド単位とを有するリン酸エステルのナトリウム塩（不飽和ＥＯリン酸エステル塩、東邦化学工業株式会社製フォスファノール（登録商標）ＲＤ－７２０、炭化水素鎖の炭素数１８、エチレンオキシド単位数７）をスラリー１Ｌに対して３ｇ（炭酸カルシウム基準で３質量％）添加し、５０℃で３０分間攪拌した後、濾別・乾燥して表面処理炭酸カルシウムを得た。
　この表面処理炭酸カルシウムを用いて、実施例１と同様にしてシートを作製し、物性を評価した。試験結果を、表１に示す。 [Example 4]
SOFTON 1000 was dispersed in purified water (concentration 100 g/L) to prepare a slurry. To this slurry, a sodium salt of a phosphoric acid ester having a long unsaturated aliphatic hydrocarbon chain and an ethylene oxide unit (unsaturated EO phosphoric acid ester salt, Phosphanol (registered trademark) RD-720 manufactured by Toho Chemical Industry Co., Ltd.) , Hydrocarbon chain carbon number 18, ethylene oxide unit number 7) is added to 1 L of slurry (3% by mass based on calcium carbonate), stirred at 50 ° C. for 30 minutes, filtered, dried and surface treated. Calcium carbonate was obtained.
Using this surface-treated calcium carbonate, a sheet was produced in the same manner as in Example 1, and its physical properties were evaluated. Table 1 shows the test results.
［比較例２］
　表面処理炭酸カルシウムとして、市販の脂肪酸表面処理重質炭酸カルシウム（平均粒子径２．２μｍ；備北粉化工業株式会社製ライトン（登録商標）Ｓ－４）を用い、実施例１と同様の操作を行った。試験結果を、表１に示す。 [Comparative Example 2]
As the surface-treated calcium carbonate, commercially available fatty acid surface-treated heavy calcium carbonate (average particle size 2.2 μm; Ryton (registered trademark) S-4 manufactured by Bihoku Funka Kogyo Co., Ltd.) was used, and the same operation as in Example 1 was performed. gone. Table 1 shows the test results.
［比較例３］
　表面処理剤としてポリオキシエチレンラウリルエーテルリン酸の代わりに無水マレイン酸変性ポリプロピレン（無水マレイン酸変性樹脂；三洋化成工業株式会社製ユーメックス（登録商標）１０１０）を用い、表面処理時の温度を１８０℃とした以外は、実施例１と同様の操作を行った。試験結果を、表１に示す。 [Comparative Example 3]
Maleic anhydride-modified polypropylene (maleic anhydride-modified resin; Umex (registered trademark) 1010 manufactured by Sanyo Chemical Industries, Ltd.) was used as a surface treatment agent instead of polyoxyethylene lauryl ether phosphate, and the temperature during surface treatment was 180 ° C. The same operation as in Example 1 was performed except that Table 1 shows the test results.
［比較例４］
　表面処理剤としてスチレン・マレイン酸エステル（マレイン酸変性樹脂；三洋化成工業株式会社製レジット（登録商標）ＳＭ－１０１）を用い、比較例３と同様の操作を行った。試験結果を、表１に示す。 [Comparative Example 4]
The same operation as in Comparative Example 3 was performed using styrene/maleic acid ester (maleic acid-modified resin; Regit (registered trademark) SM-101 manufactured by Sanyo Chemical Industries, Ltd.) as a surface treatment agent. Table 1 shows the test results.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　本発明に従い、リン酸エステルで表面処理した炭酸カルシウムを含有する実施例１～４の試料は、いずれも酢酸溶出量が小で、食品用途に適していることが判明した。特に、エチレンオキシド単位を有するリン酸エステル、中でもポリオキシエチレンラウリルエーテルリン酸で表面処理した実施例１の試料では、酢酸溶出量が大幅に低減されていた。比較例１に示されるように、炭酸カルシウムを多量充填した樹脂組成物では、酢酸溶出量が大となり、引張強度等も小さくなりがちである。一方で実施例１～４の試料では、無機物質粉末が多量に充填されているにも拘らず、酢酸溶出量だけでなく引張特性も良好であり、リン酸エステルによる表面処理の効果が示された。原料とする炭酸カルシウムが異なるので単純な比較はできないが、脂肪酸で表面処理した炭酸カルシウムを用いた比較例２の試料と比べても、実施例における酢酸溶出量は低減されており、引張強度も、特に実施例１の試料で大であった。また、４倍まで延伸しても破断せず、成形性にも優れていた。変性樹脂で表面処理した比較例３及び４の結果と比較すると、リン酸エステル、特にポリオキシエチレンラウリルエーテルリン酸による表面処理効果は、さらに顕著である。 According to the present invention, the samples of Examples 1 to 4 containing calcium carbonate surface-treated with a phosphate ester had a small amount of acetic acid elution, and were found to be suitable for food applications. In particular, the sample of Example 1 surface-treated with a phosphoric acid ester having an ethylene oxide unit, especially polyoxyethylene lauryl ether phosphoric acid, showed a significant reduction in the amount of acetic acid eluted. As shown in Comparative Example 1, the resin composition filled with a large amount of calcium carbonate tends to have a large acetic acid elution amount and a low tensile strength. On the other hand, although the samples of Examples 1 to 4 were filled with a large amount of inorganic substance powder, not only the acetic acid elution amount but also the tensile properties were good, indicating the effect of the surface treatment with phosphate ester. rice field. Since the calcium carbonate used as the raw material is different, a simple comparison cannot be made, but compared to the sample of Comparative Example 2 using calcium carbonate surface-treated with fatty acid, the acetic acid elution amount in the example was reduced, and the tensile strength was also improved. , especially the sample of Example 1 was large. Moreover, it did not break even when stretched up to 4 times, and was excellent in formability. Compared with the results of Comparative Examples 3 and 4 in which the surface was treated with a modified resin, the effect of the surface treatment with a phosphoric acid ester, particularly polyoxyethylene lauryl ether phosphoric acid, is even more remarkable.
［実施例５、比較例５］
　表面処理炭酸カルシウム７０質量部と、ポリプロピレン単独重合体３０質量部とを用いた以外は、実施例１及び比較例２と同様の操作を行った。試験結果を、表２に示す。 [Example 5, Comparative Example 5]
The same operations as in Example 1 and Comparative Example 2 were performed, except that 70 parts by mass of surface-treated calcium carbonate and 30 parts by mass of polypropylene homopolymer were used. Table 2 shows the test results.
［実施例６］
　表面処理時のリン酸エステル量を１質量部とした以外は、実施例５と同様の操作を行った。試験結果を、表２に示す。 [Example 6]
The same operation as in Example 5 was performed except that the amount of phosphate ester during surface treatment was changed to 1 part by mass. Table 2 shows the test results.
［比較例６］
　無水マレイン酸変性ポリプロピレンの代わりに無水マレイン酸変性ポリプロピレン（無水マレイン酸変性樹脂；三洋化成工業株式会社製ユーメックス（登録商標）５２００）を用い、比較例３と同様にして表面処理炭酸カルシウムを調製した。得られた表面処理炭酸カルシウム７０質量部と、ポリプロピレン単独重合体３０質量部とを用い、実施例５～６と同様の操作を行った。試験結果を、表２に示す。 [Comparative Example 6]
A surface-treated calcium carbonate was prepared in the same manner as in Comparative Example 3, using maleic anhydride-modified polypropylene (maleic anhydride-modified resin; Umex (registered trademark) 5200 manufactured by Sanyo Chemical Industries, Ltd.) instead of maleic anhydride-modified polypropylene. . Using 70 parts by mass of the obtained surface-treated calcium carbonate and 30 parts by mass of the polypropylene homopolymer, the same operations as in Examples 5 and 6 were performed. Table 2 shows the test results.
［比較例７～８］
　表面処理炭酸カルシウム７０質量部と、ポリプロピレン単独重合体３０質量部とを用いた以外は、比較例３～４と同様の操作を行った。試験結果を、表２に示す。 [Comparative Examples 7-8]
The same operations as in Comparative Examples 3 and 4 were performed except that 70 parts by mass of surface-treated calcium carbonate and 30 parts by mass of polypropylene homopolymer were used. Table 2 shows the test results.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　本発明に従い、リン酸エステルで表面処理した炭酸カルシウムを含有する実施例５及び６の試料はいずれも、汎用の脂肪酸処理炭酸カルシウムを含有する比較例５の試料に比べて酢酸溶出量が小さく、食品用途に適していることが判明した。引張特性も良好であった。一方、比較例６～８では、炭酸カルシウム粒子が変性樹脂で覆われるために酢酸溶出量は低目であったが、引張特性が著しく低下してしまった。本発明が顕著な効果を奏することが示された。 According to the present invention, both the samples of Examples 5 and 6 containing calcium carbonate surface-treated with a phosphate ester have a smaller acetic acid elution amount than the sample of Comparative Example 5 containing general-purpose fatty acid-treated calcium carbonate. It was found to be suitable for food applications. Tensile properties were also good. On the other hand, in Comparative Examples 6 to 8, since the calcium carbonate particles were covered with the modified resin, the acetic acid elution amount was rather low, but the tensile properties were remarkably deteriorated. It was shown that the present invention has remarkable effects.
　以上より、本発明に従いリン酸エステルを含有する表面処理剤で表面処理された炭酸カルシウムを含有する熱可塑性樹脂組成物は、無機物質粉末が高充填されているにも拘らず酸性条件下での溶出量が少なく、成形性が良好で、機械的強度等の物性も優れ、特に食品包装容器及び食器用に適することが明らかとなった。
  As described above, the thermoplastic resin composition containing calcium carbonate surface-treated with a surface-treating agent containing a phosphate ester according to the present invention can be used under acidic conditions despite being highly filled with inorganic powder. It has been found that the elution amount is small, moldability is good, physical properties such as mechanical strength are excellent, and it is particularly suitable for food packaging containers and tableware.

Claims (8)

  1. 　熱可塑性樹脂と無機物質粉末とを質量比５０：５０～１０：９０の割合で含有する樹脂組成物において、前記無機物質粉末は、リン酸エステルを含有する表面処理剤で表面処理された炭酸カルシウムであることを特徴とする樹脂組成物。 In a resin composition containing a thermoplastic resin and an inorganic powder at a mass ratio of 50:50 to 10:90, the inorganic powder is calcium carbonate surface-treated with a surface-treating agent containing a phosphate ester. A resin composition characterized by being
  2. 　前記リン酸エステルが、ポリオキシエチレンラウリルエーテルリン酸である、請求項１に記載の樹脂組成物。 The resin composition according to claim 1, wherein the phosphate ester is polyoxyethylene lauryl ether phosphate.
  3. 　前記炭酸カルシウムが、ＪＩＳ　Ｍ－８５１１に準じた空気透過法による平均粒子径が０．７μｍ以上６．０μｍ以下の炭酸カルシウム粒子である、請求項１又は２に記載の樹脂組成物。 The resin composition according to claim 1 or 2, wherein the calcium carbonate is calcium carbonate particles having an average particle size of 0.7 µm or more and 6.0 µm or less measured by an air permeation method according to JIS M-8511.
  4. 　前記炭酸カルシウムが、重質炭酸カルシウムである、請求項１～３の何れかに記載の樹脂組成物。 The resin composition according to any one of claims 1 to 3, wherein the calcium carbonate is ground calcium carbonate.
  5. 　前記熱可塑性樹脂が、ポリオレフィン系樹脂である、請求項１～４の何れかに記載の樹脂組成物。 The resin composition according to any one of claims 1 to 4, wherein the thermoplastic resin is a polyolefin resin.
  6. 　前記ポリオレフィン系樹脂が、ポリエチレン系樹脂及び／又はポリプロピレン系樹脂からなる、請求項５に記載の樹脂組成物。 The resin composition according to claim 5, wherein the polyolefin-based resin comprises a polyethylene-based resin and/or a polypropylene-based resin.
  7. 　請求項１～６の何れかに記載の樹脂組成物からなる成形品。 A molded article made of the resin composition according to any one of claims 1 to 6.
  8. 　請求項１～６の何れかに記載の樹脂組成物からなる食品包装容器。
          A food packaging container comprising the resin composition according to any one of claims 1 to 6.
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JP2001164017A (en) * 1999-12-07 2001-06-19 Yupo Corp Porous resin film
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JP2014019784A (en) * 2012-07-18 2014-02-03 Maruo Calcium Co Ltd Surface-treated ground calcium carbonate, process for producing the same and resin composition comprising calcium carbonate
JP2015083661A (en) * 2013-09-17 2015-04-30 東レ株式会社 Porous film and manufacturing method therefor
JP2016513159A (en) * 2013-02-22 2016-05-12 オムヤ インターナショナル アーゲー A new surface treatment of white inorganic materials for application to plastics

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Publication number Priority date Publication date Assignee Title
JPS57108164A (en) * 1980-12-24 1982-07-06 Shiraishi Chuo Kenkyusho:Kk Inorganic surface-modified filler and thermoplastic resin composition blended therewith
JPS62225556A (en) * 1986-03-28 1987-10-03 Nippon Soda Co Ltd Surface treatment for filler of unsaturated polyester resin
JP2002519468A (en) * 1998-06-30 2002-07-02 オムヤ・エス・アー Method for treating inorganic filler with phosphate ester, filler obtained by the method and use thereof
JP2001164017A (en) * 1999-12-07 2001-06-19 Yupo Corp Porous resin film
JP2014019784A (en) * 2012-07-18 2014-02-03 Maruo Calcium Co Ltd Surface-treated ground calcium carbonate, process for producing the same and resin composition comprising calcium carbonate
JP2016513159A (en) * 2013-02-22 2016-05-12 オムヤ インターナショナル アーゲー A new surface treatment of white inorganic materials for application to plastics
JP2015083661A (en) * 2013-09-17 2015-04-30 東レ株式会社 Porous film and manufacturing method therefor

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