JP6892185B1 - Inorganic substance powder-filled resin composition and molded product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin composition having good mechanical properties, particularly impact resistance, and giving a molded product which is hard to be impact-broken. SOLUTION: In an inorganic substance powder-filled resin composition containing a thermoplastic resin and an inorganic substance powder in a mass ratio of 50:50 to 10:90, the thermoplastic resin is a propylene homopolymer, a low-density polyethylene, and It is made of a hydrogenated polymer-based elastomer, and the content of the propylene homopolymer is 82% by mass or more and 90% by mass or less, and the content of the low-density polyethylene is 2% by mass based on 100% by mass of the total mass of the thermoplastic resin. An inorganic substance powder-filled resin composition comprising 6% by mass or less and a content of the hydrogenated polymer-based elastomer of 5% by mass or more and 14% by mass or less. As the hydrogenated polymer-based elastomer, an ethylene-ethylene / butylene-ethylene block copolymer is preferable. [Selection diagram] None

Description

The present invention relates to an inorganic substance powder-filled resin composition and a molded product. More specifically, the present invention provides a resin composition that gives a molded product that has good mechanical properties, particularly impact resistance, and is not easily impact-broken, despite the fact that the polypropylene resin is highly filled with an inorganic substance powder. , And a molded article comprising such a resin composition.

Conventionally, thermoplastic resins have been widely used together with paper materials derived from forest resources as materials for various industrial and household molded products, food packaging and molding packaging for general products, but environmental protection is provided. Now that it has become an international issue, it is also being considered to reduce the consumption of thermoplastic resins and paper materials in parallel with the viewpoint of making them non-toxic, recyclable, and incinerated. From this point of view, an inorganic substance powder-blended thermoplastic resin composition in which an inorganic substance powder such as calcium carbonate is highly filled in a thermoplastic resin such as polypropylene resin has been proposed and put into practical use (). For example, refer to Patent Document 1 and the like).

However, a resin composition in which a polypropylene resin is highly filled with an inorganic substance powder tends to have lower mechanical properties such as tensile strength and elongation, particularly impact strength, as compared with a general polypropylene resin not filled with the inorganic substance powder. is there. Therefore, an injection-molded product of a resin composition highly filled with an inorganic substance powder, for example, a folding container, has a problem that it is easily broken by an impact during use.

A technique for adding an elastomer component is known as a means for improving the mechanical properties of a polypropylene resin composition, particularly flexibility and impact resistance. For example, Patent Document 2 describes a technique for improving impact resistance by adding ethylene-propylene rubber or a styrene-based elastomer to a resin composition composed of polypropylene resin, ethylene-propylene block copolymer, and talc. Patent Document 3 describes a resin composition composed of two types of polypropylene-based resin, a filler, and an elastomer.

Japanese Unexamined Patent Publication No. 2013-10931 Japanese Unexamined Patent Publication No. 2009-62526 Japanese Unexamined Patent Publication No. 2013-116981

However, there is a trade-off relationship between impact resistance and mechanical strength, and a resin composition in which impact resistance and flexibility are improved by containing an elastomer component tends to be inferior in mechanical strength. Further, in a highly filled resin composition containing the same amount or more of inorganic substance powder as polypropylene resin, addition of an elastomer component does not necessarily lead to improvement of physical properties. As shown in Examples and Comparative Examples described later, if the content of the elastomer component or the like is not properly selected, the impact resistance may not be significantly improved and the strength may decrease.

The present invention has been made in view of the above circumstances, and despite the fact that the polypropylene resin is highly filled with the inorganic substance powder, it has good mechanical properties, particularly impact resistance, and is not easily impact-destructed. An object of the present invention is to provide a resin composition for giving a molded product and a molded product made of the resin composition.

As a result of diligent studies to solve the above problems, the present inventors have added a specific amount of a specific elastomer component together with a low-density polyethylene in a propylene resin composition filled with a large amount of inorganic substance powder to obtain strength. We have found that a resin composition having good mechanical properties and improved impact resistance is provided with almost no damage to the present invention, and the present invention has been reached.

That is, in the present invention, in an inorganic substance powder-filled resin composition containing a thermoplastic resin and an inorganic substance powder in a mass ratio of 50:50 to 10:90, the thermoplastic resin is a propylene homopolymer, low-density polyethylene, and the like. And hydrogenated polymer-based elastomer
Based on 100% by mass of the total mass of the thermoplastic resin, the content of the propylene homopolymer is 82% by mass or more and 90% by mass or less, the content of the low-density polyethylene is 2% by mass or more and 6% by mass or less, and the water. It is an inorganic substance powder-filled resin composition characterized in that the content of the homopolymer-based elastomer is 5% by mass or more and 14% by mass or less.

In one aspect of the inorganic substance powder-filled resin composition according to the present invention, the inorganic substance powder-filled resin composition in which the hydrogenated polymer-based elastomer is an ethylene-ethylene / butylene-ethylene block copolymer (CEBC) is shown. ..

In one aspect of the inorganic substance powder-filled resin composition according to the present invention, the inorganic substance powder-filled resin composition in which the inorganic substance powder is heavy calcium carbonate is shown.

In one aspect of the inorganic substance powder-filled resin composition according to the present invention, the heavy calcium carbonate has an average particle size of 0.7 μm or more and 6.0 μm or less by an air permeation method according to JIS M-8511. An inorganic substance powder-filled resin composition which is calcium carbonate particles is shown.

The present invention that solves the above problems is also a molded product comprising the above-mentioned inorganic substance powder-filled resin composition.

In one aspect of the molded article according to the present invention, the molded article is an injection molded article.

According to the present invention, a resin composition that provides a molded product having good mechanical properties, particularly impact resistance, and is not easily impact-destructed, despite the fact that the polypropylene resin is highly filled with an inorganic substance powder, and A molded product made of such a resin composition is provided.

Hereinafter, the present invention will be described in detail based on the embodiments.

≪Inorganic substance powder-filled resin composition≫
The inorganic substance powder-filled resin composition of the present invention contains a thermoplastic resin and an inorganic substance powder in a mass ratio of 50:50 to 10:90, and the thermoplastic resin is a propylene homopolymer or a low-density polyethylene. , And the content of propylene homopolymer is 82% by mass or more and 90% by mass or less, and the content of low-density polyethylene is 2% by mass or more, based on 100% by mass of the total mass of the thermoplastic resin. The content of the hydrogenated polymer-based elastomer is 6% by mass or less, and the content is 5% by mass or more and 14% by mass or less. Hereinafter, each component constituting the inorganic substance powder-filled resin composition (hereinafter, may be abbreviated as “resin composition”) according to the present invention will be described in detail.

<Propene homopolymer>
Propylene homopolymer (hereinafter, may be abbreviated as "PP") is a polymer obtained by substantially polymerizing only propylene, and is excellent in rigidity and heat resistance. Various products are commercially available, for example, Wintech (registered trademark) and Novatec (registered trademark) of Nippon Polypro Co., Ltd., Noblen (registered trademark) of Sumitomo Chemical Co., Ltd., and Prime Polypro (registered trademark) of Prime Polymer Co., Ltd. ), Toray Co., Ltd.'s Treca (registered trademark), SABIC Petrochemicals' SABIC (registered trademark) PP, and Sun Aroma Co., Ltd.'s Sun Aroma (registered trademark). Such PP may be included. Multiple types of PP can be used in combination.

Propylene homopolymers are classified into isotactic PP, syndiotactic PP, atactic PP, hemiisotactic PP and the like according to the difference in stereoregularity. The resin composition of the present invention may contain any of these, and a plurality of types thereof may be used in combination. Further, the homopolymer may contain a trace component produced as a by-product during polymerization, or may have a branched structure. The molecular weight is also not particularly limited. However, in the present invention, it is preferable to use PP having a mass average molecular weight of about 50,000 or more and 500,000 or less, particularly about 100,000 or more and 400,000 or less. Generally, the higher the molecular weight, the better the mechanical properties such as strength, and the lower the molecular weight, the better the moldability. Those having a mass average molecular weight of about 50,000 or more and less than 200,000 and those having a mass average molecular weight of about 200,000 or more and 500,000 or less can be used in combination. By using PPs having different molecular weights in combination, it is possible to improve the moldability and reduce the appearance defects of the molded product.

<Low density polyethylene>
Low-density polyethylene is generally polyethylene having a density of 0.930 or less, particularly about 0.9000 to 0.930, and is abbreviated as LDPE (hereinafter, may be referred to as "LDPE"). A typical LDPE has a structure in which ethylene repeating units are randomly bonded with branches, and has a density of about 0.910 to 0.925. In addition, linear low-density polyethylene having no long-chain branch (hereinafter, may be referred to as "L-LDPE"), which is obtained by copolymerizing a small amount of α-olefin with ethylene, is also known. Any of these low-density polyethylenes can be used in the present invention, and the molecular weight and molecular structure thereof are not particularly limited. For example, the copolymerization component in L-LDPE may be any such as 1-butene, 1-hexene, 4-methylpentene-1, 1-octene, and the copolymerization ratio is not particularly limited. It is also possible to use ultra-low density polyethylene (ULDPE) having a density of about 0.910 or less and less than 0.900 depending on the variety. Further, two or more kinds of low density polyethylene may be used in combination.

<Hydrogenated polymer elastomer>
The hydrogenated polymer-based elastomer is generally a polymer in which a part of the C = C double bond of the diene-based elastomer is hydrogenated (also referred to as “hydrogenation” or “hydrogenation”). HSBR hydrated with styrene-butadiene rubber, HNBR hydrated with acrylonitrile-butadiene rubber, HBR hydrated with polybutadiene, SEBS hydrated with styrene-butadiene-styrene block copolymer, styrene-isoprene-styrene block co-weight Various polymers are known, such as SEPS with hydrogenated coalescence and CIC and CEPC with hydrogenated butadiene-isoprene block copolymers (see, for example, Journal of the Japan Rubber Association, Vol. 70, p. 689). In the present invention, the molecular weight, hydrogenation rate, etc. of the hydrogenated polymer are not particularly limited. Further, these hydrogenated polymer-based elastomers may be crosslinked in the resin composition. It is also possible to use two or more hydrogenated polymer-based elastomers in combination. However, as the hydrogenated polymer-based elastomer in the resin composition of the present invention, those using only a diene monomer as a starting material, for example, hydrogenated polybutadiene or hydrogenated butadiene-isoprene block copolymer are preferable, and hydrogenated polybutadiene is particularly preferable. Such a hydrogenated polymer that does not substantially contain styrene units or achloronitrile units has excellent compatibility with the polypropylene resin or low-density polyethylene used in combination, and thus is flexible with almost no loss in the strength of the resin composition. It is possible to improve the property and impact resistance.

<Hydrogenated polybutadiene>
Hydrogenated polybutadiene is a hydride of polybutadiene, and various polymers are known depending on the structure of the raw material polybutadiene. For example, hydrogenation of 1,4-polybutadiene produces a pseudo-polyethylene structure (C) having an ethylene-ethylene bond, and hydrogenation of 1,4-polybutadiene produces a butylene structure (B), which have two bonding modes. Hydrogenation of polybutadiene further produces an ethylene-butylene structure (EB). Various hydrogenated polybutadienes containing these structures in various ratios and bonding modes and having a hydrogenation rate of about 10% to more than 90% are sold by various companies. Liquid polymers having a mass average molecular weight of about 1000 to 3000 and polymers having a functional group such as a hydroxyl group at the terminal are also commercially available. The inorganic substance powder-filled resin composition of the present invention may contain any of these hydrogenated polybutadienes. For example, a copolymer in which C, B, and EB are randomly bonded, a block copolymer of C and B or EB, or an alternate copolymer thereof can be used as a hydrogenated polymer-based elastomer component. ..

<Ethylene-ethylene / butylene-ethylene block copolymer>
However, in the present invention, the hydrogenated polymer-based elastomer is preferably an ethylene-ethylene / butylene-ethylene block copolymer (CEBC). Since CEBC has a chemical structure similar to that of polypropylene or low-density polyethylene, it has excellent compatibility with both, and can significantly improve the mechanical properties of the resin composition, particularly the impact strength. CEBC can be obtained, for example, by hydrogenation of polybutadiene having 1,4-bonds and 1,2-bonds as described above, but the hydrogenation rate does not have to be 100%. That is, in the present invention, CEBC includes a polymer having a butadiene structure and the like as well as an ethylene block and an ethylene / butylene block, and the hydrogenation rate thereof is not particularly limited. The molecular weight, the ratio of the ethylene unit to the butylene unit, the chain length of the ethylene block or the ethylene / butylene block, and the like are not particularly limited.

The inorganic substance powder-filled resin composition of the present invention contains 2 to 6% by mass of the low-density polyethylene as described above and 5 to 14% by mass of the hydrogenated polymer-based elastomer based on 100% by mass of the total mass of the thermoplastic resin. Contains. If the resin composition contains both of these in such amounts, the impact resistance can be improved without substantially impairing the strength and the like of the inorganic substance powder-filled polypropylene resin composition. Preferably, based on 100% by weight of the total mass of the thermoplastic resin, 84-88% by weight of propylene homopolymer, 3-5% by weight of low density polyethylene and 6-13% by weight, especially 7-12% by weight of water. Contains a homopolymer-based elastomer. A resin composition containing these three types of polymers in such an amount has excellent mechanical properties such as strength and impact resistance in a well-balanced manner.

In the inorganic substance powder-filled resin composition of the present invention, the thermoplastic resin contains the above-mentioned propylene homopolymer, low-density polyethylene, and hydrogenated polymer-based elastomer, but is further composed of resin components other than these. You may. Examples thereof include thermoplastic resins such as poly (meth) acrylic acid (ester), polyvinyl acetate, polyacrylonitrile, polystyrene, ABS resin, polycarbonate, polyamide, polyvinyl alcohol, petroleum hydrocarbon resin, and kumaron inden resin. By blending these resin components, each component may be more uniformly dispersed in the inorganic substance powder-filled resin composition, and the physical properties and processability may be improved.

However, in the inorganic substance powder-filled resin composition of the present invention, from the viewpoint of compatibility of various resin components, the thermoplastic resin component is preferably 90% by mass or more, more preferably 97% by mass or more, and particularly preferably substantially. The total amount is composed of the above-mentioned propylene homopolymer, low-density polyethylene, and hydrogenated polymer-based elastomer. If the resin composition is an inorganic substance powder-filled resin composition that does not substantially contain resin components other than these, there is almost no possibility that a part of the resin components will be separated, and deterioration of mechanical properties and moldability can be prevented.

<Inorganic powder>
The inorganic substance powder-filled resin composition of the present invention contains an inorganic substance powder together with the above-mentioned thermoplastic resin. The inorganic substance powder is not particularly limited, and is, for example, carbonates such as calcium, magnesium, aluminum, titanium, iron, and zinc, sulfates, silicates, phosphates, borates, oxides, or water thereof. Examples thereof include powdered Japanese products, and specific examples thereof include calcium carbonate, magnesium carbonate, zinc oxide, titanium oxide, silica, alumina, clay such as talc and kaolin, aluminum hydroxide, magnesium hydroxide, and silicic acid. Aluminum acetate, magnesium silicate, calcium silicate, aluminum sulfate, magnesium sulfate, calcium sulfate, magnesium phosphate, barium sulfate, silica sand, carbon black, zeolite, molybdenum, diatomaceous soil, sericite, silas, calcium sulfite, sodium sulfate, titanium Examples thereof include potassium acid acid, bentonite, wollastonite, dolomite, graphite and the like. These may be synthetic or derived from natural minerals, and they may be contained alone or in combination of two or more.

Further, the shape of the inorganic substance powder is not particularly limited, and may be in the form of particles, flakes, granules, fibers, or the like. Further, it may be in the form of particles, which may be spherical as generally obtained by a synthetic method, or may have an indefinite shape as obtained by pulverizing the collected natural minerals. ..

These inorganic substance powders are preferably calcium carbonate, magnesium carbonate, zinc oxide, titanium oxide, silica, alumina, clay such as talc and kaolin, aluminum hydroxide, magnesium hydroxide and the like, and those containing calcium carbonate in particular. preferable. Further, the calcium carbonate is either so-called light calcium carbonate prepared by a synthetic method or so-called heavy calcium carbonate obtained by mechanically crushing and _{classifying a natural raw material containing CaCO 3 as a main component such as limestone.} It may be present, or it may be a combination of these.

However, in the present invention, it is preferable to use an inorganic substance powder containing heavy calcium carbonate. Here, heavy calcium carbonate is obtained by mechanically crushing and processing natural limestone or the like, and is clearly distinguished from synthetic calcium carbonate produced by a chemical precipitation reaction or the like. The pulverization method includes a dry method and a wet method, and the dry method is preferable.

Unlike light calcium carbonate obtained by a synthetic method, heavy calcium carbonate particles are characterized by surface irregularity and a large specific surface area due to the particle formation being carried out by a pulverization treatment. Since the heavy calcium carbonate particles have such irregular shape and large specific surface area, the heavy calcium carbonate particles have more contact interfaces with the thermoplastic resin when blended in the thermoplastic resin. Has and is effective for uniform dispersion.

Although not particularly limited, the specific surface area of the heavy calcium carbonate particles ^{is about 3,000 cm 2} / g or more and 35,000 cm ² / g or less, although it depends on the average particle size. desired. The specific surface area referred to here is based on the air permeation method. When the specific surface area is within this range, the deterioration of workability of the obtained molded product tends to be suppressed.

Further, the indeterminate form of the heavy calcium carbonate particles can be expressed by the low degree of spheroidization of the particle shape, and is not particularly limited, but specifically, the roundness is 0.50. More than 0.95 or less, more preferably 0.55 or more and 0.93 or less, still more preferably 0.60 or more and 0.90 or less. When the roundness of the heavy calcium carbonate particles is within this range, the strength and moldability of the molded product are also appropriate. Here, the roundness can be expressed by (projected area of particles) / (area of a circle having the same perimeter as the projected perimeter of particles). The method for measuring the roundness is not particularly limited, and for example, the projected area of the particles and the projected peripheral length of the particles may be measured from a micrograph, or a commercially available image analysis software may be used.

Further, the surface may be surface-modified according to a conventional method in order to enhance the dispersibility or reactivity of the inorganic substance powder. Examples of the surface modification method include a physical method such as plasma treatment and a method of chemically surface-treating the surface with a coupling agent or a surfactant. Examples of the coupling agent include a silane coupling agent and a titanium coupling agent. The surfactant may be anionic, cationic, nonionic or amphoteric, and examples thereof include higher fatty acids, higher fatty acid esters, higher fatty acid amides and higher fatty acid salts. On the contrary, it may contain an inorganic substance powder that has not been surface-treated.

The inorganic substance powder such as heavy calcium carbonate particles is not particularly limited, but the average particle size thereof is preferably 0.5 μm or more and 9.0 μm or less, and more preferably 0.7 μm or more and 6.0 μm or less. , 1.0 μm or more and 4.0 μm or less is more preferable, and 1.2 μm or more and 3.0 μm or less is particularly preferable. The average particle size of the inorganic substance powder described in the present 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 the measuring device, for example, a specific surface area measuring device SS-100 manufactured by Shimadzu Corporation can be preferably used. When the average particle size is larger than 9.0 μm, for example, when a sheet-shaped molded product is formed, the inorganic substance powder protrudes from the surface of the molded product and falls off, depending on the layer thickness of the molded product. There is a risk of damage to the surface properties and mechanical strength. 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 become too fine, the viscosity may increase remarkably when kneaded with the above-mentioned resin, which may make it difficult to manufacture a molded product. Such a problem can be prevented by setting the average particle size of the inorganic substance powder to 0.5 μm or more, further 0.7 μm or more and 6.0 μm or less, particularly 1.0 μm or more and 3.0 μm or less.

As described above, in the present invention, it is preferable to use calcium carbonate as the inorganic substance powder. If desired, the calcium carbonate comprises a first calcium carbonate having an average particle size of 0.5 μm or more and less than 2.0 μm, particularly 0.7 μm or more and less than 2.0 μm, as measured by the air permeation method according to JIS M-8511. It may contain a second calcium carbonate having an average particle size of 2.0 μm or more and less than 9.0 μm, particularly 2.0 μm or more and less than 6.0 μm, as measured by the air permeation method according to JIS M-8511. This makes it possible to improve the surface properties of the molded product and the physical properties such as printability and blocking property. In addition, uneven distribution of calcium carbonate is suppressed, a molded product having good appearance and mechanical properties such as elongation at break can be obtained, and it is possible to reduce the loss of calcium carbonate from the molded product of the resin composition. .. 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 more preferably 0.85 or less. It is desirable that can be roughly classified into 0.10 to 0.70, more preferably 0.10 to 0.50. This is because a particularly excellent effect can be expected by using those having a certain difference in average particle size in combination. Further, it is desirable that the coefficient of variation (Cv) of the distribution of the particle size (μm) of each of the first calcium carbonate and the second calcium carbonate is about 0.01 to 0.10. It is desirable that it is about 0.08. If the variation in particle size defined by the coefficient of variation (Cv) is about this level, it is considered that each powder group can give a more complementary effect. The mass ratio of the first calcium carbonate to the second calcium carbonate is preferably 90: 10 to 98: 2, particularly about 92: 8 to 95: 5. Three or more calcium carbonate groups having different average particle size distributions may be used. Further, it is preferable that both the first calcium carbonate and the second calcium carbonate are surface-treated heavy calcium carbonate.

In the inorganic substance powder-filled resin composition of the present invention, the above-mentioned thermoplastic resin and inorganic substance powder are contained in a mass ratio of 50:50 to 10:90. This is because if the content of the inorganic substance powder is small, it is difficult to obtain physical properties such as the texture and strength of the resin composition, and if it is too large, kneading and molding are difficult, and the flexibility is insufficient. 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. Considering that the flexibility and impact resistance of the inorganic substance powder-filled resin composition can be greatly affected by the low-density polyethylene and the hydrogenated polymer-based elastomer, the low-density polyethylene and the hydrogenated polymer-based elastomer are combined with the above mass ratio. The mass ratio with the inorganic substance powder may be specified. By setting the mass ratio of the total amount of low-density polyethylene and hydrogenated polymer-based elastomer to the inorganic substance powder in the range of, for example, 3:97 to 15:85, particularly 5:95 to 10:90, flexibility can be achieved. A resin composition having a particularly excellent balance between impact resistance and strength can be obtained.

<Other additives>
If necessary, other additives may be added to the inorganic substance powder-filled resin composition according to the present invention as an auxiliary agent. Other additives include, for example, colorants, lubricants, coupling agents, fluidity improvers (fluidity modifiers), crosslinkers, dispersants, antioxidants, UV absorbers, flame retardants, stabilizers, and antistatic agents. An inhibitor, a foaming agent, a plasticizer and the like may be blended. These additives may be used alone or in combination of two or more. Further, 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. In the inorganic substance powder-filled resin composition according to the present invention, the amount of these other additives added is not particularly limited as long as it does not impair the desired physical properties and processability, but for example, the inorganic substance powder-filled resin. When the total mass of the composition is 100%, each of these other additives is about 0 to 10% by mass, particularly about 0.04 to 5% by mass, and the total mass of the other additives is 10% by mass. It is desirable that the mixture be blended in a proportion of% or less.

Of these, the ones considered to be important will be described below with examples, but the present invention is not limited to these.

Examples of the plasticizer include triethyl citrate, acetyl triethyl citrate, dibutyl phthalate, diaryl phthalate, dimethyl phthalate, diethyl phthalate, di-2-methoxyethyl phthalate, dibutyl tartrate, and o-benzoyl benzoic acid. Examples include esters, diacetin, epoxidized soybean oil and the like. These plasticizers are usually blended in an amount of about several mass% with respect to the thermoplastic resin, but the amount is not limited to these ranges, and depending on the purpose of the molded product, about 20 to 50 parts by mass of epoxidized soybean oil or the like is blended. It is also possible to do. However, in the inorganic substance powder-filled resin composition of the present invention, the blending amount thereof is preferably 0.5 to 10 parts by mass, particularly about 1 to 5 parts by mass with respect to 100 parts by mass of the thermoplastic resin.

As the colorant, any known organic pigment, inorganic pigment or dye can be used. Specifically, organic pigments such as azo-based, anthraquinone-based, phthalocyanine-based, quinacridone-based, isoindolinone-based, geoosazine-based, perinone-based, quinophthalone-based, and perylene-based pigments, ultramarine blue, titanium oxide, titanium yellow, and iron oxide. Examples include inorganic pigments such as (valve handle), chromium oxide, zinc oxide, and carbon black.

Examples of the lubricant include fatty acid-based lubricants such as stearic acid, hydroxystearic acid, composite stearic acid, and oleic acid; aliphatic alcohol-based lubricants; stearoamide, oxystearoamide, oleylamide, elcilamide, ricinolamide, behenamide, and methylol. Aliphatic amide lubricants such as amides, methylene bisstearoamides, methylene bisstearobehenamides, higher fatty acids bisamide acids, complex amides; stearic acid-n-butyl, methyl hydroxystearate, polyhydric alcohol fatty acid esters, An aliphatic ester-based lubricant such as a saturated fatty acid ester and an ester-based wax; a fatty acid metal soap-based lubricant, for example, zinc stearate and the like can be mentioned.

As the antioxidant, a phosphorus-based antioxidant, a phenol-based antioxidant, and a pentaerythritol-based antioxidant can be used. Phosphorus-based, more specifically, phosphorus-based antioxidant stabilizers such as phosphite ester and phosphoric acid ester are preferably used. Examples of the phosphite ester include phosphorous acid triesters such as triphenylphosphite, trisnonylphenylphosphite, and tris (2,4-di-t-butylphenyl) phosphite, diesters, and monoesters. Can be mentioned.

Examples of the phosphoric acid ester include trimethyl phosphate, triethyl phosphate, tributyl phosphate, trioctyl phosphate, triphenyl phosphate, tricresyl phosphate, tris (nonylphenyl) phosphate, 2-ethylphenyldiphenyl phosphate and the like. These phosphorus-based antioxidants may be used alone or in combination of two or more.

Phenolic antioxidants include α-tocopherol, butylhydroxytoluene, cinapyl 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-methylphenylacrylate, 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. are exemplified, and these can be used alone or in combination of two or more kinds.

The flame retardant is not particularly limited, and for example, a halogen-based flame retardant or a non-phosphorus-based halogen-based flame retardant such as a phosphorus-based flame retardant or a metal hydrate can be used. Specific examples of the halogen-based flame retardant include halogenated bisphenol compounds such as halogenated bisphenyl alkane, halogenated bisphenyl ether, halogenated bisphenyl thioether, and halogenated bisphenyl sulfone, brominated bisphenol A, and bromine. Bisphenol-bis (alkyl ether) compounds such as bisphenol S, chlorinated bisphenol A, and chlorinated bisphenol S, and as phosphorus-based flame retardants, tris (diethylphosphinic acid) aluminum, bisphenol A bis (diphenyl phosphate) , Triaryl isopropyl phosphate, cresildi 2,6-xylenyl phosphate, aromatic condensed phosphate, etc., as metal hydrates, for example, aluminum trihydrate, magnesium dihydration, or a combination thereof. Etc. can be exemplified respectively, and these can be used alone or in combination of two or more kinds. It works as a flame-retardant aid and can improve the flame-retardant effect more effectively. Further, for example, antimony oxide such as antimony trioxide and antimony pentoxide, zinc oxide, iron oxide, aluminum oxide, molybdenum oxide, titanium oxide, calcium oxide, magnesium oxide and the like can be used in combination as a flame retardant aid. ..

The effervescent agent is a material that is mixed or press-fitted into an inorganic substance powder-filled resin composition that is a raw material that has been melted in a melt-kneader and undergoes a phase change from solid to gas, liquid to gas, or the gas itself. It is mainly used to control the foaming ratio (foaming density) of the foamed sheet. As for the foaming agent, the one that is liquid at room temperature changes its phase to a gas depending on the resin temperature and dissolves in the molten resin, and the one that is gas at room temperature does not change its phase and dissolves in the molten resin as it is. When the molten resin is extruded into a sheet from an extrusion die, the foaming agent dispersed and dissolved in the molten resin expands inside the sheet because the pressure is released, and foams by forming a large number of fine closed cells in the sheet. A sheet is obtained. The foaming agent secondarily acts as a plasticizer that lowers the melt viscosity of the raw material resin composition, lowering the temperature for bringing the raw material resin composition into a plasticized state.

Examples of the effervescent agent include aliphatic hydrocarbons such as propane, butane, pentane, hexane and heptane; alicyclic hydrocarbons such as cyclobutane, cyclopentane and cyclohexane; chlorodifluoromethane, difluoromethane, trifluoromethane and trichlorofluoromethane. Methane, dichloromethane, dichlorofluoromethane, dichlorodifluoromethane, chloromethane, chloroethane, dichlorotrifluoroethane, dichloropentafluoroethane, tetrafluoroethane, difluoroethane, pentafluoroethane, trifluoroethane, dichlorotetrafluoroethane, trichlorotrifluoroethane , Tetrachlorodifluoroethane, perfluorocyclobutane and other halogenated hydrocarbons; carbon dioxide, nitrogen, air and other inorganic gases; water and the like.

Further, as the foaming agent, for example, a carrier resin containing an active ingredient of the foaming agent can be preferably used. Examples of the carrier resin include crystalline olefin resins. Of these, crystalline polypropylene resin is preferable. In addition, examples of the active ingredient include hydrogen carbonate and the like. Of these, bicarbonate is preferred. A foaming agent concentrate containing a crystalline polypropylene resin as a carrier resin and a bicarbonate as a pyrolysis foaming agent is preferable.

The content of the foaming agent contained in the foaming agent in the molding step can be appropriately set according to the amount of the propylene homopolymer, the low-density polyethylene, the hydrogenated polymer-based elastomer, the inorganic substance powder, and the like, and is filled with the inorganic substance powder. The range is preferably 0.04 to 5.00% by mass with respect to the total mass of the resin composition.

As the fluidity adjusting agent, various conventional ones can be used. Examples include, but are not limited to, peroxides such as dialkyl peroxide, such as 1,4-bis [(t-butylperoxy) isopropyl] benzene. Depending on the type of thermoplastic resin used, these peroxides also act as cross-linking agents. In particular, when the hydrogenated polymer-based elastomer has a diene-derived structural unit, a part of the copolymer is crosslinked by the action of the peroxide, which helps to control the physical properties and processability of the resin composition. obtain. The amount of peroxide added is not particularly limited, but is in the range of 0.04 to 2.00% by mass, particularly about 0.05 to 0.50% by mass, based on the total mass of the inorganic substance powder-filled resin composition. It is preferable to do so.

<< Manufacturing method of inorganic substance powder-filled resin composition >>
As a method for producing the inorganic substance powder-filled resin composition of the present invention, an ordinary method can be used, and it may be appropriately set according to the molding method (extrusion molding, injection molding, vacuum molding, etc.), for example. The propylene homopolymer, low-density polyethylene, and hydrogenated polymer-based elastomer and inorganic substance powder may be kneaded and melted before being charged into the molding machine from the hopper. The substance powder may be kneaded and melted. In melt kneading, it is preferable to knead by applying a high shear stress while uniformly dispersing each component. As the mixing device, various devices such as a general extruder, a kneader, and a Banbury mixer can be used, but it is preferable to knead with a twin-screw kneader, for example.

In the production method of the present invention, the kneading order of the propylene homopolymer, the low-density polyethylene, the hydrogenated polymer-based elastomer, and the inorganic substance powder is not particularly limited. For example, these four parties can be kneaded at the same time, and each thermoplastic resin component can be kneaded once, and then the thermoplastic resin mixture and the inorganic substance powder or the like can be kneaded. It is also possible to knead the propylene homopolymer and the inorganic substance powder once, and then knead the low-density polyethylene and the hydrogenated polymer-based elastomer. Since low-density polyethylene and hydrogenated polymer-based elastomers generally tend to be flexible and have low melt viscosities, the final kneading method, such as the latter method, makes each component in the inorganic powder-filled resin composition more homogeneous. It may be advantageous to disperse in. This method can also be utilized for effective utilization of products collected from the market and mill scraps. The composition in which the inorganic substance powder is highly filled in the thermoplastic resin has already been put into practical use as described above, and is also used in the general market. Especially in a manufacturing factory, scraps of these compositions may be stored in a state where the composition is controlled for each lot. The inorganic substance powder-filled resin composition of the present invention can also be produced by kneading a specified amount of low-density polyethylene and a hydrogenated polymer-based elastomer with these recovered products and scraps.

In the method for producing an inorganic substance powder-filled resin composition of the present invention, the inorganic substance powder-filled resin composition may be in the form of pellets or not in the form of pellets, but in the case of pellets, the composition may be in the form of pellets. The shape of the above is not particularly limited, and for example, pellets such as a cylinder, a sphere, and an elliptical sphere may be formed.

The size of the pellet may be appropriately set according to the shape, but for example, in the case of a spherical pellet, the diameter may be 1 to 10 mm. In the case of an elliptical spherical pellet, the pellet has an elliptical shape with an aspect ratio of 0.1 to 1.0, and may be 1 to 10 mm in length and width. In the case of cylindrical pellets, the diameter may be in the range of 1 to 10 mm and the length may be in the range of 1 to 10 mm. These shapes may be formed on the pellets after the kneading step described later. The shape of the pellet may be formed according to a conventional method.

≪Molded product≫
The molded product according to the present invention is a molded product made of the above-mentioned inorganic substance powder-filled resin composition.

The shape of the molded product according to the present invention is not particularly limited and may be of various shapes, but for example, a sheet, particularly a substitute for paper or synthetic paper, a brush, a shoehorn, or the like. It can be molded as a housing for daily necessities, remote controls, telephones, etc., and various molded products such as food containers and other containers. Since the molded product of the present invention has excellent impact resistance, it is suitable as a housing or sheet to which force is applied during assembly or use, a folding container to which impact is applied during use, and other daily necessities.

The wall thickness of the molded product according to the present invention is not particularly limited, and may vary from thin to thick depending on the form of the molded product. For example, the wall thickness is 40 μm. Molded articles of ~ 40 mm, more preferably a wall thickness of 50 μm to 30 mm are shown. If the wall thickness is within this range, it is possible to form a homogeneous and defect-free molded product without causing problems in moldability and workability and without causing uneven thickness.

In particular, when the form of the molded product is a sheet, it is more preferable that the wall thickness is 50 μm to 1,000 μm, and further preferably the wall thickness is 50 μm to 400 μm. A sheet having a wall thickness within such a range can be suitably used in place of general printing / information and packaging paper or synthetic paper.

≪Manufacturing method of molded products≫
The method for producing the molded product of the present invention is not particularly limited as long as it can be molded into a desired shape, and any conventionally known method such as extrusion molding, injection molding, vacuum molding, blow molding, or calendar molding can be used. Molding is possible. In particular, injection molding is preferable. Furthermore, even when the inorganic substance powder-filled resin composition according to the present invention contains a foaming agent to obtain a molded product in the form of a foam, a method for molding the foam as long as it can be molded into a desired shape. As conventionally known, for example, a liquid phase foaming method such as injection foaming, extrusion foaming, foam blow, or a solid phase foaming method such as bead foaming, batch foaming, press foaming, or atmospheric secondary foaming is used. It is also possible. In one aspect of the above-mentioned thermoplastic composition containing crystalline polypropylene as a carrier resin and hydrogen carbonate as a pyrolytic foaming agent, an injection foaming method and an extrusion foaming method can be preferably used.

<Manufacturing method of injection molded products>
Since the inorganic substance powder-filled resin composition of the present invention is also excellent in moldability as described above, it can be molded into articles having various shapes by injection molding. The present invention also includes molded articles of the above-mentioned inorganic substance powder-filled resin compositions, particularly injection molded articles. Since the molded product of the present invention has good mechanical properties, particularly impact resistance, it has an advantage that it is not easily damaged even if it receives an impact during use. The inorganic substance powder-filled resin composition of the present invention also has excellent flexibility and is unlikely to crack or chip even when a force is applied. Therefore, after molding into a plurality of parts having unevenness to be fitted, the parts are fitted together. It is suitable for molding processing including steps. For example, the handle of a brush or safety razor and other parts (main body part), or parts of a housing such as a remote controller or a telephone are separately injection-molded, and then an external force is applied to fit the two together. The product can be manufactured.

The molding temperature in injection molding, extrusion molding, etc. varies to some extent depending on the molding method, etc., and therefore cannot be unconditionally specified. For example, the temperature is 180 to 260 ° C, more preferably 190 to 230 ° C. If this is the case, the inorganic substance powder-filled resin composition according to the present invention can be molded into a predetermined shape without having good drawdown characteristics and ductility, and without causing local modification of the composition.

<Sheet manufacturing method>
In the embodiment in which the molded product according to the present invention is a sheet, the manufacturing method thereof is not particularly limited as long as it is in the form of a sheet, and the conventional known molding method as described above can be used. In consideration of the smoothness of the sheet surface, it is preferable to adopt a method of making a sheet by extrusion molding with an extruder.

For molding, a direct method in which the kneading step and the step of molding into a sheet shape are continuously performed may be used, or for example, a method using a T-die type twin-screw extrusion molding machine may be used.
Further, in the case of molding into a sheet shape, it is possible to stretch in the uniaxial direction or the biaxial direction or in the multiaxial direction (stretching by the tubular method, etc.) at the time of the molding or after the molding. In the case of biaxial stretching, sequential biaxial stretching or simultaneous biaxial stretching may be used.

When the sheet after molding is stretched (for example, longitudinally and / or laterally stretched), minute voids are generated in the sheet. The whiteness of the sheet becomes good due to the formation of minute voids in the sheet.

Hereinafter, the present invention will be described in more detail based on Examples. It should be noted that these examples are specific embodiments and practices in order to facilitate understanding of the concept and scope of the present invention disclosed in the present specification and described in the appended claims. The present invention is described only for the purpose of exemplifying the embodiments, and the present invention is not limited to these examples.

[Examples 1 to 4, Comparative Examples 1 to 3]
Various inorganic substance powder-filled resin compositions were prepared using the following raw materials, molded into test pieces, and subjected to a physical characteristic test.
-PP (propylene homopolymer): Propylene homopolymer manufactured by Japan Polypropylene Corporation (MFR: 0.5 g / 10 min)
-LDPE (Low Density Polyethylene): Low density polyethylene manufactured by Japan Polyethylene Corporation, density 0.920 g / cm ³
CEBC (Hydrogenated Polymer Elastomer): Ethylene-ethylene / butylene-ethylene block copolymer manufactured by JSR Corporation, DYNARON (registered trademark) 6200P
SEBS (Hydrogenated Polymer Elastomer): Styrene-ethylene / butylene-styrene block copolymer manufactured by JSR Corporation, DYNARON (registered trademark) 8601P
-CC (calcium carbonate): Heavy calcium carbonate manufactured by Bikita Powder Industry Co., Ltd. (with surface treatment, average particle size 2.20 μm measured by the air permeation method according to JIS M-8511)

Each of the above raw materials was charged into a co-rotating twin-screw extruder HK-25D (φ25 mm, L / D = 41) manufactured by Parker Corporation at the mass ratio shown in Table 1 described later, and the cylinder temperature was 190 to 190 to Pellets were prepared by extruding strands at 200 ° C., cooling and cutting. Next, the pellets were put into an injection molding machine to mold a dumbbell-shaped test piece or the like.

The tensile properties and Charpy impact strength of each test piece prepared as described above were evaluated by the following test method. The results are shown in Table 1 below.
(Tensile characteristics)
The tensile elastic modulus and the elongation at break point were measured using Autograph AG-100kNXplus (Shimadzu Corporation) under the conditions of 23 ° C. and 50% Rhes according to JIS K 7161-2: 2014. The stretching speed was 10 mm / min.
(Charpy impact strength)
The 80 mm × 10 mm test piece was measured according to ISO179 / 1eA. Not performed for some samples.

Example 1 containing 2 to 6% by mass of low-density polyethylene and 5 to 14% by mass of ethylene-ethylene-butylene-ethylene block copolymer (CEBC) together with a propylene homopolymer per 100% by mass of the thermoplastic resin component. In each of the resin compositions of No. 3 to 3, the Charpy impact strength ^{exceeded 7 kJ / m 2,} which was improved to more than 4 times the value in Comparative Example 1 containing no polymer. The breaking point strengths were almost the same as the values in Comparative Example 1. The elongation at break point was also improved to about four times the value in Comparative Example 1. According to the present invention, it has been found that by containing a specific amount of LDPE and CEBC, mechanical strength including impact strength is improved in a well-balanced manner.

Comparing the resin composition of Comparative Example 2 having a CEBC content of less than 5% by mass and Comparative Example 3 having an LDPE content of more than 6% by mass with the resin composition of Comparative Example 1, the improvement in Charpy impact strength was achieved. Was small, and the breaking point strength was slightly reduced. It was shown that it is important to select the content of low-density polyethylene and hydrogenated polymer-based elastomer in order to improve mechanical properties such as impact strength in a well-balanced manner. Further, the resin composition of Example 4 containing a hydrogenated styrene elastomer (SEBS) together with LDPE had good tensile properties, but had the same Charpy impact strength as the resin composition containing CEBC (Example). It was inferior to 1). As the hydrogenated polymer-based elastomer, it was shown that an ethylene-ethylene / butylene-ethylene block copolymer is preferable.

From the above, even if the resin composition is highly filled with the inorganic substance powder, it is good mechanical as long as the thermoplastic resin component contains a specific amount of low-density polyethylene and a hydrogenated polymer-based elastomer together with the propylene homopolymer. It has been clarified that the resin composition has characteristics, particularly impact resistance, and gives a molded product that is not easily impact-broken. Further, it was shown that an ethylene-ethylene / butylene-ethylene block copolymer is preferable as the hydrogenated polymer-based elastomer.

Claims (6)

In an inorganic substance powder-filled resin composition containing a thermoplastic resin and an inorganic substance powder in a mass ratio of 50:50 to 10:90, the thermoplastic resin is a propylene homopolymer, a low-density polyethylene, and a hydrogenated polymer system. Made of elastomer
Based on 100% by mass of the total mass of the thermoplastic resin, the content of the propylene homopolymer is 82% by mass or more and 90% by mass or less, the content of the low-density polyethylene is 2% by mass or more and 6% by mass or less, and the water. An inorganic substance powder-filled resin composition, wherein the content of the homopolymer-based elastomer is 5% by mass or more and 14% by mass or less. The inorganic substance powder-filled resin composition according to claim 1, wherein the hydrogenated polymer-based elastomer is an ethylene-ethylene / butylene-ethylene block copolymer (CEBC). The inorganic substance powder-filled resin composition according to claim 1 or 2, wherein the inorganic substance powder is heavy calcium carbonate. The inorganic substance powder-filled resin composition according to claim 3, wherein the heavy calcium carbonate is a heavy calcium carbonate particle having an average particle diameter of 0.7 μm or more and 6.0 μm or less by an air permeation method according to JIS M-8511. Stuff. A molded product comprising the inorganic substance powder-filled resin composition according to any one of claims 1 to 4. The molded product according to claim 5, wherein the molded product is an injection molded product.