WO2022102488A1 - Resin composition and molded body - Google Patents

Resin composition and molded body Download PDF

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Publication number
WO2022102488A1
WO2022102488A1 PCT/JP2021/040494 JP2021040494W WO2022102488A1 WO 2022102488 A1 WO2022102488 A1 WO 2022102488A1 JP 2021040494 W JP2021040494 W JP 2021040494W WO 2022102488 A1 WO2022102488 A1 WO 2022102488A1
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WO
WIPO (PCT)
Prior art keywords
resin composition
mass
parts
less
dispersant
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PCT/JP2021/040494
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French (fr)
Japanese (ja)
Inventor
征之 赤田
麻希子 大島
Original Assignee
三菱エンジニアリングプラスチックス株式会社
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Application filed by 三菱エンジニアリングプラスチックス株式会社 filed Critical 三菱エンジニアリングプラスチックス株式会社
Priority to CN202180075575.8A priority Critical patent/CN116529314A/en
Priority to JP2022561851A priority patent/JPWO2022102488A1/ja
Publication of WO2022102488A1 publication Critical patent/WO2022102488A1/en

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    • 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
    • C08K3/02—Elements
    • C08K3/04—Carbon
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L59/00—Compositions of polyacetals; Compositions of derivatives of polyacetals

Definitions

  • the present invention relates to a resin composition and a molded product.
  • the present invention relates to a resin composition suitable for use in digital equipment parts.
  • Engineering plastics polyacetal resin has excellent mechanical properties, sliding properties, friction / wear properties, heat resistance, molding processability, etc. Therefore, the resin composition containing the polyacetal resin is widely used for various mechanical parts such as automobiles and OA equipment, electric parts, and the like.
  • Patent Document 1 states that carbon black (B) and a dispersant (C) are larger than 4 parts by mass in total with respect to 100 parts by mass of the polyacetal resin (A).
  • ⁇ 5> The resin composition according to ⁇ 1> or ⁇ 2>, wherein the content of the carbon black is more than 1.5 parts by mass and 4 parts by mass or less with respect to 100 parts by mass of the polyacetal resin.
  • the dispersant contains at least one selected from the group consisting of polyolefin wax, fatty acid, fatty acid amide, polyalkylene glycol and silicone. .. ⁇ 7> The resin composition according to any one of ⁇ 1> to ⁇ 5>, wherein the dispersant contains at least two kinds selected from the group consisting of polyolefin wax, fatty acid, fatty acid amide, polyalkylene glycol and silicone. ..
  • ⁇ 8> The resin composition according to ⁇ 6> or ⁇ 7>, wherein the dispersant contains a fatty acid amide.
  • the dispersant contains silicone.
  • the dispersant contains an aliphatic amide and a silicone.
  • the amount of fatty acid amide in the dispersant is 40% by mass or less with respect to the total amount of the dispersant.
  • the resin composition according to one. ⁇ 13> The resin composition according to any one of ⁇ 1> to ⁇ 12>, which is used for a diaphragm spring of a digital camera. ⁇ 14> Any one of ⁇ 1> to ⁇ 13>, wherein the total light transmittance measured according to JIS-K-7136 when the resin composition is molded to a thickness of 0.05 mm is 2% or less.
  • the resin composition according to one. ⁇ 16> A molded product formed from the resin composition according to any one of ⁇ 1> to ⁇ 15>.
  • ⁇ 17> The molded body according to ⁇ 16>, wherein the molded body is a digital device component.
  • ⁇ 18> The molded body according to ⁇ 16>, wherein the molded body is a diaphragm spring of a digital camera.
  • ⁇ 19> The molded product according to any one of ⁇ 16> to ⁇ 18>, wherein the thickness of the thinnest portion of the molded product is 0.1 mm or less.
  • ⁇ 20> The molded product according to any one of ⁇ 16> to ⁇ 18>, wherein the thickness of the thinnest portion of the molded product is 0.075 mm or less.
  • the present embodiment will be described in detail.
  • the following embodiments are examples for explaining the present invention, and the present invention is not limited to the present embodiment.
  • "-" is used in the meaning which includes the numerical values described before and after it as the lower limit value and the upper limit value.
  • various physical property values and characteristic values shall be at 23 ° C. unless otherwise specified. If the standards shown in this specification differ from year to year in terms of measurement method, etc., they shall be based on the standards at the time of filing unless otherwise specified.
  • the resin composition of the present embodiment contains carbon black and a dispersant in a total ratio of more than 2.0 parts by mass and 10.0 parts by mass or less with respect to 100 parts by mass of the polyacetal resin, and the total of the carbon black and the dispersant.
  • a resin composition in which the proportion of carbon black in the amount is more than 60% by mass and less than 100% by mass, and the melt volume rate is measured under the conditions of 190 ° C. and a load of 2.16 kg weight of the resin composition (hereinafter, "" It is characterized in that (sometimes referred to as "MVR”) is more than 50 cm 3/10 minutes and less than 100 cm 3/10 minutes. With such a configuration, it becomes possible to provide a resin composition that can be thin-walled and has excellent light-shielding properties.
  • the resin composition of the present embodiment contains a polyacetal resin.
  • a molded product having excellent slidability can be obtained.
  • the polyacetal resin used in the present embodiment is a copolymer containing an oxymethylene group and an oxyalkylene group having 2 or more carbon atoms as a constituent unit.
  • Examples of the oxyalkylene group having 2 or more carbon atoms include an oxyethylene group, an oxypropylene group, and an oxybutylene group. Of these, the oxyethylene group is preferable because it more sufficiently suppresses the deterioration of the characteristics of the polyacetal resin.
  • the ratio of the oxyalkylene group having 2 or more carbon atoms is preferably 0.3 to 6.0 mol% with respect to 100 mol% of the oxymethylene group.
  • the polyacetal resin has more sufficient thermal stability.
  • the content is 6.0 mol% or less, the crystallinity of the polyacetal resin is further improved, and it is possible to sufficiently suppress that the strength of the resin composition is significantly lowered and the creep fatigue characteristics are lowered.
  • the above ratio is in the range of 0.3 to 6.0 mol%, the thermal stability of the polyacetal resin is further improved as compared with the case where the above range is out of the range, and the resin composition is further excellent in impact resistance. It is possible to manufacture a molded product.
  • the above ratio is more preferably 0.5 to 5.5 mol%, further preferably 0.7 to 5.0 mol%, and further preferably 1.0 to 4.5 mol%. preferable.
  • trioxane is usually used as a main raw material.
  • cyclic formal or cyclic ether can be used.
  • the cyclic formal include 1,3-dioxolane, 1,3-dioxane, 1,3-dioxepan, 1,3-dioxocan, 1,3,5-trioxepan, 1,3,6-trioxocan and the like.
  • Specific examples of the cyclic ether include ethylene oxide, propylene oxide and butylene oxide.
  • 1,3-dioxolane for example, 1,3-dioxolane may be used, and for the introduction of an oxypropylene group, 1,3-dioxane may be used. May use 1,3-dioxepan.
  • the polyacetal resin used in this embodiment preferably has a high MVR.
  • the MVR measured under the conditions of 190 ° C. and a load of 2.16 kg weight of the polyacetal resin used in the present embodiment is preferably more than 45 cm 3/10 minutes, preferably 50 cm 3/10 minutes or more. More preferably, it is more preferably 60 cm 3/10 minutes or more, further preferably 65 cm 3/10 minutes or more, and even more preferably 70 cm 3/10 minutes or more.
  • the MVR of the polyacetal resin is preferably less than 100 cm 3/10 minutes, more preferably 90 cm 3/10 minutes or less, still more preferably 80 cm 3/10 minutes or less, and 76 cm 3/10 minutes or less. The following is more preferable. By setting the value to the upper limit or less, the shape of the thin wall tends to be maintained more effectively. MVR is measured according to the description of Examples described later.
  • the content of the polyacetal resin in the resin composition of the present embodiment is preferably 90% by mass or more, more preferably 93% by mass or more, and further preferably 95% by mass or more in the resin composition. preferable. By setting the value to the lower limit or more, the shape of the thin wall tends to be maintained more effectively.
  • the content of the polyacetal resin is preferably 99% by mass or less in the resin composition. By setting the value to the upper limit or less, it tends to be possible to achieve better light-shielding property with a thin wall.
  • the resin composition of the present embodiment may contain only one type of polyacetal resin, or may contain two or more types of polyacetal resin. When two or more kinds are contained, it is preferable that the total amount is within the above range.
  • the resin composition of the present embodiment contains carbon black. By containing carbon black, a molded product having excellent light-shielding properties can be obtained.
  • carbon black used in the present embodiment for example, furnace black, acetylene black, channel black, oil smoke black (lamp black) and the like can be used.
  • the average particle size of carbon black is not particularly limited, but is preferably 5 nm or more, more preferably 10 nm or more, and further preferably 15 nm or more. By setting the value to the lower limit or higher, the dispersibility of carbon black tends to be further improved.
  • the average particle size of carbon black is preferably 50 nm or less, more preferably 40 nm or less, further preferably 30 nm or less, and even more preferably 25 nm or less. By setting the value to the upper limit or less, the light-shielding property tends to be further improved.
  • the average particle size refers to the average value of the particle sizes of a plurality of carbon blacks observed using a scanning electron microscope.
  • the content of carbon black in the resin composition of the present embodiment is preferably more than 1.5 parts by mass with respect to 100 parts by mass of the polyacetal resin. By setting the value to the lower limit or more, the light-shielding property tends to be further improved. Further, the content of the carbon black is preferably 9 parts by mass or less, more preferably 6 parts by mass or less, and further preferably 4 parts by mass or less with respect to 100 parts by mass of the polyacetal resin. It is more preferably 3 parts by mass or less. By setting the value to the upper limit or less, the fluidity required for thin-wall molding tends to be more effectively maintained.
  • the resin composition of the present embodiment may contain only one type of carbon black, or may contain two or more types of carbon black. When two or more kinds are contained, it is preferable that the total amount is within the above range.
  • the resin composition of the present embodiment contains a dispersant.
  • a dispersant By containing the dispersant, carbon black can be dispersed more effectively, and a molded product having more excellent light-shielding property can be obtained.
  • the dispersant is not particularly limited as long as it can disperse carbon black in the polyacetal resin, but preferably contains at least one selected from the group consisting of polyolefin wax, fatty acid, fatty acid amide, polyalkylene glycol and silicone. ..
  • One embodiment of the dispersant is to include a fatty acid amide.
  • Another embodiment of the dispersant is to include silicone.
  • Another embodiment of the dispersant is comprising an aliphatic amide and a silicone.
  • the slidability of the molded product can be further improved.
  • a combination of at least two or more (preferably 2 to 4, more preferably 3) selected from the group consisting of polyolefin wax, fatty acid, fatty acid amide, polyalkylene glycol and silicone is preferable.
  • the dispersant preferably contains at least two kinds selected from the group consisting of polyolefin wax, fatty acid, fatty acid amide, polyalkylene glycol and silicone, and the dispersant of polyolefin wax, fatty acid amide and silicone. It is more preferred to use a mixture.
  • polyolefin wax examples include polyethylene wax and polypropylene wax.
  • fatty acids examples include higher fatty acids such as stearic acid, oleic acid, octanoic acid, lauric acid, ricinoleic acid, and behenic acid.
  • Fatty acid amide is a compound obtained by dehydration reaction between higher fatty acid and / or polybasic acid and diamine.
  • the higher fatty acid a saturated aliphatic monocarboxylic acid having 16 or more carbon atoms, for example, 16 to 30 carbon atoms is preferable, and specific examples thereof include palmitic acid, stearic acid, behenic acid, and montanic acid.
  • the polybasic acid is a carboxylic acid of dibasic acid or more, for example, aliphatic dicarboxylic acids such as malonic acid, succinic acid, adipic acid, sebacic acid, pimelli acid, and azelaic acid, and aromatic acids such as phthalic acid and terephthalic acid.
  • Examples thereof include dicarboxylic acids and alicyclic dicarboxylic acids such as cyclohexyldicarboxylic acid and cyclohexylsuccinic acid.
  • Examples of the diamine include ethylenediamine, 1,3-diaminopropane, 1,4-diaminobutane, hexamethylenediamine, m-xylylenediamine, tolylenediamine, paraxylylenediamine, phenylenediamine, isophoronediamine and the like.
  • Specific examples of the fatty acid amide include stearylamide, behenylamide, montanylamide, methylenebisstearylamide, ethylenebisstearylamide and the like.
  • polyalkylene glycols examples include polymethylene glycol, polyethylene glycol, polypropylene glycol, polybutylene glycol, polypentylene glycol, polyhexylene glycol, polyheptylene glycol, polyoctylene glycol, polynonylene glycol, and polydecylene glycol. And so on.
  • silicone examples include silicone oil having properties such as oil, rubber, and resin, silicone rubber, silicone resin, and silicone grease to which metal soap and the like are added.
  • Specific examples of silicone include polydimethylsiloxane, organosiloxane in which part of the methyl group of polydimethylsiloxane is replaced with a phenyl group, and alkyl in which part of the methyl group of polydimethylsiloxane is hydrogen or having 2 or more carbon atoms.
  • Organosiloxane replaced with a group organosiloxane with a part of the methyl group of polydimethylsiloxane replaced with a halogenated phenyl group, organosiloxane with a part of the methyl group of polydimethylsiloxane replaced with a fluoroester group, epoxy Examples thereof include modified organosiloxanes, amino-modified organosiloxanes, alcohol-modified organosiloxanes, alkylaralkyl organosiloxanes, and polyether-modified organosiloxanes.
  • Silicone preferably has a kinematic viscosity of 500,000 cSt or more at 25 ° C.
  • a silicone having a kinematic viscosity of 500,000 cSt or more at 25 ° C. the appearance of the obtained molded product can be improved and higher sliding characteristics can be maintained.
  • the upper limit of the kinematic viscosity is not particularly specified, but is preferably 2 million cSt or less, for example.
  • the content of the dispersant in the resin composition of the present embodiment is preferably 0.5 parts by mass or more, more preferably 0.7 parts by mass or more, and 0. It is more preferably 8 parts by mass or more. By setting the value to the lower limit or higher, the dispersibility of carbon black tends to be further improved.
  • the content of the dispersant is preferably 7.0 parts by mass or less, more preferably 6.0 parts by mass or less, and 4.0 parts by mass or less with respect to 100 parts by mass of the polyacetal resin. It is more preferably 2.0 parts by mass or less. By setting the value to the upper limit or less, the strength inherent in the polyacetal resin tends to be effectively maintained.
  • the resin composition of the present embodiment may contain only one kind of dispersant, or may contain two or more kinds of dispersants. When two or more kinds are contained, it is preferable that the total amount is within the above range.
  • the total content of carbon black and the dispersant in the resin composition of the present embodiment is more than 2.0 parts by mass and preferably 2.5 parts by mass or more with respect to 100 parts by mass of the polyacetal resin. It is more preferably 8 parts by mass or more. By setting the value to the lower limit or more, the light-shielding property tends to be further improved.
  • the total content of the carbon black and the dispersant is 10.0 parts by mass or less, preferably 8.0 parts by mass or less, and 6.0 parts by mass or less with respect to 100 parts by mass of the polyacetal resin. It is more preferably 5.0 parts by mass or less, further preferably 4.0 parts by mass or less. By setting the value to the upper limit or less, the strength inherent in the polyacetal resin can be more effectively exhibited.
  • the ratio of carbon black to the total amount of carbon black and the dispersant is more than 60% by mass, preferably 61% by mass or more, and preferably 62% by mass or more. Is more preferable.
  • the proportion of carbon black in the total amount of the carbon black and the dispersant is less than 100% by mass, preferably 90% by mass or less, more preferably 80% by mass or less, and 75% by mass. The following is more preferable.
  • By setting the value to the upper limit or less there is a tendency that the shape of the thin wall can be maintained more effectively while ensuring the light-shielding property.
  • the resin composition of the present embodiment may contain components other than the above-mentioned components.
  • specific examples of other components include inorganic fillers, heat stabilizers, antioxidants, weather-resistant stabilizers, light-resistant stabilizers, ultraviolet absorbers, crystal nucleating agents, antistatic agents, antibacterial agents and the like. These can be used alone or in combination of two or more.
  • the resin composition in the present embodiment can be configured to be substantially free of an inorganic filler. The term "substantially free" means that the content of the inorganic filler in the resin composition in the present embodiment is less than 1% by mass of the resin composition.
  • the resin composition of the present embodiment is blended so that the total of the polyacetal resin, carbon black and the dispersant and other components to be blended as necessary is 100% by mass. Further, the total amount of the polyacetal resin, carbon black and the dispersant preferably occupies 95 to 100% by mass, and more preferably 99 to 100% by mass of the resin composition.
  • the method for producing the resin composition of the present embodiment is not particularly limited, and the resin composition can be prepared by various methods conventionally known as a method for preparing the resin composition. For example, (1) a method of mixing all the components constituting the resin composition, supplying the mixture to an extruder and melt-kneading the mixture to obtain a pellet-shaped composition, and (2) one of the components constituting the resin composition. A method of supplying a portion from the main feed port of the extruder and melt-kneading the residual components from the side feed port to obtain a pellet-shaped composition, (3) once preparing pellets having different compositions by extrusion or the like, and then pelleting the pellets.
  • Polyacetal resin pellets or crushed material are mixed with a predetermined amount of compounding ingredients, or the surface of polyacetal resin pellets or crushed material is coated with a predetermined amount of compounding ingredients. Then, a method of obtaining a predetermined resin composition or the like can be adopted.
  • the resin composition of the present embodiment has a high MVR.
  • the MVR of the resin composition measured under the conditions of 190 ° C. and a load of 2.16 kg is preferably more than 50 cm 3/10 minutes, preferably 55 cm 3/10 minutes or more, and is preferably 60 cm 3/10 . It is more preferably more than a minute, more preferably 61 cm 3/10 minutes or more, and even more preferably 62 cm 3/10 minutes or more.
  • the MVR is less than 100 cm 3/10 minutes, preferably 90 cm 3/10 minutes or less, and more preferably 80 cm 3/10 minutes or less. By setting the value to the upper limit or less, the shape of the thin wall tends to be maintained more effectively. MVR is measured according to the description of Examples described later.
  • the resin composition of the present embodiment is preferably excellent in light-shielding property.
  • the total light transmittance measured according to JIS-K-7136 when the resin composition is molded to a thickness of 0.05 mm is preferably 2% or less, preferably 1.5% or less. More preferably, it is more preferably 1% or less.
  • the lower limit of the total light transmittance is preferably 0%.
  • the total light transmittance is measured according to the description of Examples described later.
  • the present embodiment also includes a molded product formed from the resin composition of the present embodiment.
  • the molded product in the present embodiment has excellent light-shielding properties and can be a thin-walled molded product.
  • the thickness of the thinnest portion of the molded product can be 0.1 mm or less, and further can be 0.075 mm or less.
  • the lower limit of the thickness of the thinnest portion is practically 0.01 mm or more, and may be 0.02 mm or more.
  • the resin composition of the present embodiment can be molded by a known molding method such as injection molding, extrusion molding, compression molding, blow molding, or vacuum molding.
  • the resin composition and molded body of the present embodiment can be suitably used for automobile parts, electric / electronic parts, precision machine parts, building materials / piping parts, daily necessities, cosmetic parts, medical equipment parts, and the like, but digital equipment parts. It is preferably used for the aperture spring of a digital camera.
  • Raw material polyacetal resin (A1) An oximethylene copolymer obtained by copolymerizing trioxane and 1,3-dioxolane so that the ratio of oxyethylene groups is 1.4 mol% with respect to 100 mol% of oxymethylene groups, which is an MVR ( Oxymethylene copolymer polyacetal resin (A2): 190 ° C., 2.16 kg weight) is 75 cm 3/10 min.
  • A1 An oximethylene copolymer obtained by copolymerizing trioxane and 1,3-dioxolane so that the ratio of oxyethylene groups is 1.4 mol% with respect to 100 mol% of oxymethylene groups, which is an MVR ( Oxymethylene copolymer polyacetal resin (A2): 190 ° C., 2.16 kg weight) is 75 cm 3/10 min.
  • Ethylene bisstearylamide (C1) Product name "EB-FF", Kao polyethylene wax (C2): Product name "High Wax 720P”, Silicone (C3) manufactured by Mitsui Chemicals, Inc .: Kinematic viscosity at 25 ° C: 1 million cSt silicone
  • MVR of resin and resin composition The MVR (unit: cm 3/10 min) of the polyacetal resin and the resin composition (pellet) obtained above was measured at 190 ° C. and a load of 2.16 kg in accordance with ISO1133. The results of MVR of the resin composition (pellets) are shown in Table 1.
  • the resin composition (pellet) obtained above was dried at 80 ° C. for 3 hours and then pressed using a press machine to prepare a test sheet having a thickness of 0.05 mm ⁇ 20 mm ⁇ 20 mm.
  • the total light transmittance (unit:%) of the obtained test sheet was measured according to JIS-K-7136 using a haze meter. The results are shown in Table 1.
  • the press machine used was the product name "Mini Test Press” manufactured by Toyo Seiki Co., Ltd.
  • As the haze meter NDH4000 manufactured by Nippon Denshoku Co., Ltd. was used.
  • a cylindrical thrust test piece was produced by injection molding at a cylinder temperature of 200 ° C. and a mold temperature of 80 ° C. The measurement was carried out using a thrust type friction and wear tester manufactured by Orientec Co., Ltd. at a temperature of 23 ° C., a humidity of 50%, a surface pressure of 0.25 MPa, and a linear velocity of 0.1 m / sec.
  • the “total amount of (C)” means the total amount (unit: parts by mass) of (C1) to (C3).
  • the “amount of (B) + (C)” means the total amount of (B) and (C1) to (C3), that is, the total amount of carbon black and the dispersant (unit: parts by mass). .. Therefore, " ⁇ (B) / [(B) + (C)] ⁇ x 100" indicates the ratio (unit: mass%) of carbon black to the total amount of carbon black and the dispersant.
  • the resin composition of the present invention is also excellent in fluidity and is excellent in moldability of a thin-walled molded product.
  • the contents of carbon black and the dispersant do not meet the scope of the present invention (Comparative Example 1)
  • the light-shielding property is lowered.
  • the MVR of the resin composition does not meet the scope of the present invention
  • the fluidity is slightly inferior, and the fluidity is insufficient for use in a thin-walled molded body such as a draw spring of a digital camera (comparison).
  • Example 3 when (B) / (B) + (C) ⁇ 100 was 60% by mass or less, the total light transmittance was high (Comparative Example 3).
  • the content of carbon black was high, the fluidity decreased (Comparative Example 4).

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Abstract

Provided are: a resin composition that can be thinly molded and that is superior in terms of light blocking properties; and a molded body employing the resin composition. The present invention provides a resin composition: that contains carbon black and a dispersant at, in total, a proportion greater than 2.0 parts by mass and equal to or less than 10.0 parts by mass with respect to 100 parts by mass of a polyacetal resin; and in which the proportion of the carbon black with respect to the total quantity of the carbon black and the dispersant is greater than 60 mass% and less than 100 mass%, wherein the melt volume rate of the resin composition measured under the conditions of 190°C and a load of 2.16 kg-weight is greater than 50 cm3/10 min and less than 100 cm3/10 min.

Description

樹脂組成物および成形体Resin composition and molded product
　本発明は樹脂組成物および成形体に関する。特に、デジタル機器部品用途に適した樹脂組成物に関する。 The present invention relates to a resin composition and a molded product. In particular, the present invention relates to a resin composition suitable for use in digital equipment parts.
　エンジニアリングプラスチックスのポリアセタール樹脂は、優れた機械的性質、摺動特性、摩擦・磨耗特性、耐熱性、成形加工性などを有している。このため、ポリアセタール樹脂を含む樹脂組成物は、自動車、ＯＡ機器などの各種機械部品や電気部品等に広く用いられている。 Engineering plastics polyacetal resin has excellent mechanical properties, sliding properties, friction / wear properties, heat resistance, molding processability, etc. Therefore, the resin composition containing the polyacetal resin is widely used for various mechanical parts such as automobiles and OA equipment, electric parts, and the like.
　ポリアセタール樹脂を用いた樹脂組成物の一例として、特許文献１には、ポリアセタール樹脂（Ａ）１００質量部に対して、カーボンブラック（Ｂ）および分散剤（Ｃ）が合計で４質量部より大きく１０質量部以下の割合で配合され、前記カーボンブラック（Ｂ）および前記分散剤（Ｃ）の合計配合量中の前記カーボンブラックの割合が６０質量％より大きく１００質量％未満である、ポリアセタール樹脂組成物が開示されている。 As an example of a resin composition using a polyacetal resin, Patent Document 1 states that carbon black (B) and a dispersant (C) are larger than 4 parts by mass in total with respect to 100 parts by mass of the polyacetal resin (A). A polyacetal resin composition blended in a proportion of parts by mass or less, wherein the proportion of the carbon black in the total blending amount of the carbon black (B) and the dispersant (C) is more than 60% by mass and less than 100% by mass. Is disclosed.
特開２０１７－０１４３０４号公報Japanese Unexamined Patent Publication No. 2017-014304
　ところで、近年、ポリアセタール樹脂を用いた各種機械部品や電気部品においても、用途に応じて、軽量化や高い遮光性が求められるようになっている。軽量化するためには、成形体を薄くすることが必要であるが、成形体を薄くするほど、遮光性が劣る傾向にある。そこで、薄肉成形体において、遮光性を確保するために、カーボンブラックと共に、カーボンブラックの分散剤を配合することが考えられる。しかしながら、遮光性を確保するために上記添加剤を配合すると、流動性が劣り、薄肉成形が困難となる場合がある。
　本発明はかかる課題を解決することを目的とするものであって、薄肉成形が可能であって、かつ、遮光性に優れた樹脂組成物、および、前記樹脂組成物を用いた成形体を提供することを目的とする。 By the way, in recent years, various mechanical parts and electric parts using polyacetal resin are also required to be lightweight and have high light-shielding property depending on the application. In order to reduce the weight, it is necessary to make the molded body thinner, but the thinner the molded body, the worse the light-shielding property tends to be. Therefore, in the thin-walled molded product, in order to secure the light-shielding property, it is conceivable to add a carbon black dispersant together with the carbon black. However, if the above additive is added in order to secure the light-shielding property, the fluidity may be inferior and it may be difficult to form a thin wall.
An object of the present invention is to solve such a problem, and to provide a resin composition capable of thin-wall molding and excellent light-shielding property, and a molded body using the resin composition. The purpose is to do.
　上記課題のもと、本発明者が検討を行った結果、カーボンブラックおよび分散剤の配合量を調整しつつ、樹脂組成物自体のＭＶＲを調整することにより、上記課題を解決しうることを見出した。
　具体的には、下記手段により、上記課題は解決された。
＜１＞ポリアセタール樹脂１００質量部に対し、
カーボンブラックおよび分散剤を合計で２．０質量部超１０．０質量部以下の割合で含み、
前記カーボンブラックおよび分散剤の合計量中のカーボンブラックの割合が６０質量％超１００質量％未満である樹脂組成物であって、
樹脂組成物の１９０℃、荷重２．１６ｋｇ重の条件で測定されたメルトボリュームレイトが５０ｃｍ３／１０分超１００ｃｍ３／１０分未満である、樹脂組成物。
＜２＞前記樹脂組成物の１９０℃、荷重２．１６ｋｇ重の条件で測定されたメルトボリュームレイトが６０ｃｍ３／１０分超１００ｃｍ３／１０分未満である、＜１＞に記載の樹脂組成物。
＜３＞前記カーボンブラックの含有量が、ポリアセタール樹脂１００質量部に対し、１．５質量部超９質量部以下である、＜１＞または＜２＞に記載の樹脂組成物。
＜４＞前記カーボンブラックの含有量が、ポリアセタール樹脂１００質量部に対し、１．５質量部超６質量部以下である、＜１＞または＜２＞に記載の樹脂組成物。
＜５＞前記カーボンブラックの含有量が、ポリアセタール樹脂１００質量部に対し、１．５質量部超４質量部以下である、＜１＞または＜２＞に記載の樹脂組成物。
＜６＞前記分散剤がポリオレフィンワックス、脂肪酸、脂肪酸アミド、ポリアルキレングリコールおよびシリコーンからなる群より選ばれる少なくとも１種を含む、＜１＞～＜５＞のいずれか１つに記載の樹脂組成物。
＜７＞前記分散剤がポリオレフィンワックス、脂肪酸、脂肪酸アミド、ポリアルキレングリコールおよびシリコーンからなる群より選ばれる少なくとも２種を含む、＜１＞～＜５＞のいずれか１つに記載の樹脂組成物。
＜８＞前記分散剤が脂肪酸アミドを含む、＜６＞または＜７＞に記載の樹脂組成物。
＜９＞前記分散剤がシリコーンを含む、＜６＞～＜８＞のいずれか１つに記載の樹脂組成物。
＜１０＞前記分散剤が脂肪族アミドおよびシリコーンを含む、＜７＞に記載の樹脂組成物。
＜１１＞前記分散剤中の脂肪酸アミド量が、分散剤合計量に対して４０質量％以下である、＜１＞～＜１０＞のいずれか１つに記載の樹脂組成物。
＜１２＞前記ポリアセタール樹脂の１９０℃、荷重２．１６ｋｇ重の条件で測定されたメルトボリュームレイトが４５ｃｍ３／１０分超１００ｃｍ３／１０分未満である、＜１＞～＜１１＞のいずれか１つに記載の樹脂組成物。
＜１３＞デジタルカメラの絞りばね用である、＜１＞～＜１２＞のいずれか１つに記載の樹脂組成物。
＜１４＞前記樹脂組成物を０．０５ｍｍの厚さに成形したときのＪＩＳ－Ｋ－７１３６に従って測定した全光線透過率が、２％以下である、＜１＞～＜１３＞のいずれか１つに記載の樹脂組成物。
＜１５＞前記樹脂組成物を０．０５ｍｍの厚さに成形したときのＪＩＳ－Ｋ－７１３６に従って測定した全光線透過率が、１％以下である、＜１＞～＜１３＞のいずれか１つに記載の樹脂組成物。
＜１６＞＜１＞～＜１５＞のいずれか１つに記載の樹脂組成物から形成された成形体。
＜１７＞前記成形体がデジタル機器部品である、＜１６＞に記載の成形体。
＜１８＞前記成形体がデジタルカメラの絞りばねである、＜１６＞に記載の成形体。
＜１９＞前記成形体の最薄肉部の厚さが０．１ｍｍ以下である、＜１６＞～＜１８＞のいずれか１つに記載の成形体。
＜２０＞前記成形体の最薄肉部の厚さが０．０７５ｍｍ以下である、＜１６＞～＜１８＞のいずれか１つに記載の成形体。 As a result of studies by the present inventor based on the above problems, it has been found that the above problems can be solved by adjusting the MVR of the resin composition itself while adjusting the blending amounts of carbon black and the dispersant. rice field.
Specifically, the above problem was solved by the following means.
<1> For 100 parts by mass of polyacetal resin
Contains carbon black and dispersant in a total ratio of more than 2.0 parts by mass and not more than 10.0 parts by mass.
A resin composition in which the proportion of carbon black in the total amount of the carbon black and the dispersant is more than 60% by mass and less than 100% by mass.
A resin composition having a melt volume rate of more than 50 cm 3/10 minutes and less than 100 cm 3/10 minutes measured under the conditions of 190 ° C. and a load of 2.16 kg.
<2> The resin composition according to <1>, wherein the melt volume rate of the resin composition measured under the conditions of 190 ° C. and a load of 2.16 kg is more than 60 cm 3/10 minutes and less than 100 cm 3/10 minutes. ..
<3> The resin composition according to <1> or <2>, wherein the content of the carbon black is more than 1.5 parts by mass and 9 parts by mass or less with respect to 100 parts by mass of the polyacetal resin.
<4> The resin composition according to <1> or <2>, wherein the content of the carbon black is more than 1.5 parts by mass and 6 parts by mass or less with respect to 100 parts by mass of the polyacetal resin.
<5> The resin composition according to <1> or <2>, wherein the content of the carbon black is more than 1.5 parts by mass and 4 parts by mass or less with respect to 100 parts by mass of the polyacetal resin.
<6> The resin composition according to any one of <1> to <5>, wherein the dispersant contains at least one selected from the group consisting of polyolefin wax, fatty acid, fatty acid amide, polyalkylene glycol and silicone. ..
<7> The resin composition according to any one of <1> to <5>, wherein the dispersant contains at least two kinds selected from the group consisting of polyolefin wax, fatty acid, fatty acid amide, polyalkylene glycol and silicone. ..
<8> The resin composition according to <6> or <7>, wherein the dispersant contains a fatty acid amide.
<9> The resin composition according to any one of <6> to <8>, wherein the dispersant contains silicone.
<10> The resin composition according to <7>, wherein the dispersant contains an aliphatic amide and a silicone.
<11> The resin composition according to any one of <1> to <10>, wherein the amount of fatty acid amide in the dispersant is 40% by mass or less with respect to the total amount of the dispersant.
<12> Any of <1> to <11>, wherein the melt volume rate of the polyacetal resin measured under the conditions of 190 ° C. and a load of 2.16 kg is more than 45 cm 3/10 minutes and less than 100 cm 3/10 minutes. The resin composition according to one.
<13> The resin composition according to any one of <1> to <12>, which is used for a diaphragm spring of a digital camera.
<14> Any one of <1> to <13>, wherein the total light transmittance measured according to JIS-K-7136 when the resin composition is molded to a thickness of 0.05 mm is 2% or less. The resin composition according to one.
<15> Any one of <1> to <13>, wherein the total light transmittance measured according to JIS-K-7136 when the resin composition is molded to a thickness of 0.05 mm is 1% or less. The resin composition according to one.
<16> A molded product formed from the resin composition according to any one of <1> to <15>.
<17> The molded body according to <16>, wherein the molded body is a digital device component.
<18> The molded body according to <16>, wherein the molded body is a diaphragm spring of a digital camera.
<19> The molded product according to any one of <16> to <18>, wherein the thickness of the thinnest portion of the molded product is 0.1 mm or less.
<20> The molded product according to any one of <16> to <18>, wherein the thickness of the thinnest portion of the molded product is 0.075 mm or less.
　本発明により、薄肉成形が可能であって、かつ、遮光性に優れた樹脂組成物、および、前記樹脂組成物を用いた成形体を提供可能になった。 INDUSTRIAL APPLICABILITY According to the present invention, it has become possible to provide a resin composition capable of thin-wall molding and having excellent light-shielding properties, and a molded product using the resin composition.
　以下、本発明を実施するための形態（以下、単に「本実施形態」という）について詳細に説明する。なお、以下の本実施形態は、本発明を説明するための例示であり、本発明は本実施形態のみに限定されない。
　なお、本明細書において「～」とはその前後に記載される数値を下限値および上限値として含む意味で使用される。
　本明細書において、各種物性値および特性値は、特に述べない限り、２３℃におけるものとする。
　本明細書で示す規格が年度によって、測定方法等が異なる場合、特に述べない限り、出願時点における規格に基づくものとする。 Hereinafter, embodiments for carrying out the present invention (hereinafter, simply referred to as “the present embodiment”) will be described in detail. The following embodiments are examples for explaining the present invention, and the present invention is not limited to the present embodiment.
In addition, in this specification, "-" is used in the meaning which includes the numerical values described before and after it as the lower limit value and the upper limit value.
In the present specification, various physical property values and characteristic values shall be at 23 ° C. unless otherwise specified.
If the standards shown in this specification differ from year to year in terms of measurement method, etc., they shall be based on the standards at the time of filing unless otherwise specified.
　本実施形態の樹脂組成物は、ポリアセタール樹脂１００質量部に対し、カーボンブラックおよび分散剤を合計で２．０質量部超１０．０質量部以下の割合で含み、前記カーボンブラックおよび分散剤の合計量中のカーボンブラックの割合が６０質量％超１００質量％未満である樹脂組成物であって、樹脂組成物の１９０℃、荷重２．１６ｋｇ重の条件で測定されたメルトボリュームレイト（以下、「ＭＶＲ」ということがある）が５０ｃｍ３／１０分超１００ｃｍ３／１０分未満であることを特徴とする。
　このような構成とすることにより、薄肉成形が可能であって、かつ、遮光性に優れた樹脂組成物を提供可能になる。 The resin composition of the present embodiment contains carbon black and a dispersant in a total ratio of more than 2.0 parts by mass and 10.0 parts by mass or less with respect to 100 parts by mass of the polyacetal resin, and the total of the carbon black and the dispersant. A resin composition in which the proportion of carbon black in the amount is more than 60% by mass and less than 100% by mass, and the melt volume rate is measured under the conditions of 190 ° C. and a load of 2.16 kg weight of the resin composition (hereinafter, "" It is characterized in that (sometimes referred to as "MVR") is more than 50 cm 3/10 minutes and less than 100 cm 3/10 minutes.
With such a configuration, it becomes possible to provide a resin composition that can be thin-walled and has excellent light-shielding properties.
＜ポリアセタール樹脂＞
　本実施形態の樹脂組成物は、ポリアセタール樹脂を含む。ポリアセタール樹脂を含むことにより、摺動性に優れた成形体が得られる。
　本実施形態で用いられるポリアセタール樹脂は、オキシメチレン基と、炭素数が２以上のオキシアルキレン基とを構成単位として含むコポリマーである。 <Polyacetal resin>
The resin composition of the present embodiment contains a polyacetal resin. By containing the polyacetal resin, a molded product having excellent slidability can be obtained.
The polyacetal resin used in the present embodiment is a copolymer containing an oxymethylene group and an oxyalkylene group having 2 or more carbon atoms as a constituent unit.
　炭素数が２以上のオキシアルキレン基としては、例えばオキシエチレン基、オキシプロピレン基、および、オキシブチレン基などが挙げられる。中でも、ポリアセタール樹脂の特徴が損なわれることをより十分に抑制するという理由からは、オキシエチレン基が好ましい。 Examples of the oxyalkylene group having 2 or more carbon atoms include an oxyethylene group, an oxypropylene group, and an oxybutylene group. Of these, the oxyethylene group is preferable because it more sufficiently suppresses the deterioration of the characteristics of the polyacetal resin.
　上記ポリアセタール樹脂においては、炭素数２以上のオキシアルキレン基の割合はオキシメチレン基１００モル％に対して０．３～６．０モル％であることが好ましい。０．３モル％以上とすることにより、ポリアセタール樹脂がより十分な熱安定性を有する。また、６．０モル％以下とすることにより、ポリアセタール樹脂の結晶性がより向上し、樹脂組成物の強度が大きく低下したり、クリープ疲労特性が低下したりすることを十分に抑制できる。上記割合が０．３～６．０モル％の範囲内にあると、上記範囲を外れる場合と比べて、ポリアセタール樹脂の熱安定性がより向上し、樹脂組成物は、耐衝撃性にさらに優れた成形体を製造できる。上記割合は、０．５～５．５モル％であることがより好ましく、０．７～５．０モル％であることがさらに好ましく、１．０～４．５モル％であることが一層好ましい。 In the above polyacetal resin, the ratio of the oxyalkylene group having 2 or more carbon atoms is preferably 0.3 to 6.0 mol% with respect to 100 mol% of the oxymethylene group. When the content is 0.3 mol% or more, the polyacetal resin has more sufficient thermal stability. Further, when the content is 6.0 mol% or less, the crystallinity of the polyacetal resin is further improved, and it is possible to sufficiently suppress that the strength of the resin composition is significantly lowered and the creep fatigue characteristics are lowered. When the above ratio is in the range of 0.3 to 6.0 mol%, the thermal stability of the polyacetal resin is further improved as compared with the case where the above range is out of the range, and the resin composition is further excellent in impact resistance. It is possible to manufacture a molded product. The above ratio is more preferably 0.5 to 5.5 mol%, further preferably 0.7 to 5.0 mol%, and further preferably 1.0 to 4.5 mol%. preferable.
　上記ポリアセタール樹脂を製造するためには通常、主原料としてトリオキサンが用いられる。また、ポリアセタール樹脂中に炭素数２以上のオキシアルキレン基を導入するには、例えば環状ホルマールや環状エーテルを用いることができる。環状ホルマールの具体例としては、例えば１，３－ジオキソラン、１，３－ジオキサン、１，３－ジオキセパン、１，３－ジオキソカン、１，３，５－トリオキセパン、１，３，６－トリオキソカン等が挙げられ、環状エーテルの具体例としては、例えばエチレンオキシド、プロピレンオキシドおよびブチレンオキシド等が挙げられる。ポリアセタール樹脂中にオキシエチレン基を導入するには、例えば１，３－ジオキソランを用いればよく、オキシプロピレン基を導入するには、１，３－ジオキサンを用いればよく、オキシブチレン基を導入するには、１，３－ジオキセパンを用いればよい。 In order to produce the above polyacetal resin, trioxane is usually used as a main raw material. Further, in order to introduce an oxyalkylene group having 2 or more carbon atoms into the polyacetal resin, for example, cyclic formal or cyclic ether can be used. Specific examples of the cyclic formal include 1,3-dioxolane, 1,3-dioxane, 1,3-dioxepan, 1,3-dioxocan, 1,3,5-trioxepan, 1,3,6-trioxocan and the like. Specific examples of the cyclic ether include ethylene oxide, propylene oxide and butylene oxide. For the introduction of an oxyethylene group into a polyacetal resin, for example, 1,3-dioxolane may be used, and for the introduction of an oxypropylene group, 1,3-dioxane may be used. May use 1,3-dioxepan.
　本実施形態で用いるポリアセタール樹脂は、ＭＶＲが高めであることが好ましい。具体的には、本実施形態で用いるポリアセタール樹脂の１９０℃、荷重２．１６ｋｇ重の条件で測定されたＭＶＲが、４５ｃｍ３／１０分超であることが好ましく、５０ｃｍ３／１０分以上であることがより好ましく、６０ｃｍ３／１０分以上であることがさらに好ましく、６５ｃｍ３／１０分以上であることが一層好ましく、７０ｃｍ３／１０分以上であることがより一層好ましい。前記下限値以上とすることにより、流動性が高くなる傾向にある。前記ポリアセタール樹脂のＭＶＲは、１００ｃｍ３／１０分未満であることが好ましく、９０ｃｍ３／１０分以下であることがより好ましく、８０ｃｍ３／１０分以下であることがさらに好ましく、７６ｃｍ３／１０分以下であることが一層好ましい。前記上限値以下とすることにより、薄肉の形状をより効果的に維持できる傾向にある。
　ＭＶＲは、後述する実施例の記載に従って測定される。 The polyacetal resin used in this embodiment preferably has a high MVR. Specifically, the MVR measured under the conditions of 190 ° C. and a load of 2.16 kg weight of the polyacetal resin used in the present embodiment is preferably more than 45 cm 3/10 minutes, preferably 50 cm 3/10 minutes or more. More preferably, it is more preferably 60 cm 3/10 minutes or more, further preferably 65 cm 3/10 minutes or more, and even more preferably 70 cm 3/10 minutes or more. By setting the value to the lower limit or higher, the liquidity tends to increase. The MVR of the polyacetal resin is preferably less than 100 cm 3/10 minutes, more preferably 90 cm 3/10 minutes or less, still more preferably 80 cm 3/10 minutes or less, and 76 cm 3/10 minutes or less. The following is more preferable. By setting the value to the upper limit or less, the shape of the thin wall tends to be maintained more effectively.
MVR is measured according to the description of Examples described later.
　本実施形態の樹脂組成物におけるポリアセタール樹脂の含有量は、樹脂組成物中、９０質量％以上であることが好ましく、９３質量％以上であることがより好ましく、９５質量％以上であることがさらに好ましい。前記下限値以上とすることにより、薄肉の形状をより効果的に維持できる傾向にある。また、前記ポリアセタール樹脂の含有量は、樹脂組成物中、９９質量％以下であることが好ましい。前記上限値以下とすることにより、薄肉でのより優れた遮光性を達成できる傾向にある。
　本実施形態の樹脂組成物は、ポリアセタール樹脂を１種のみ含んでいてもよいし、２種以上含んでいてもよい。２種以上含む場合、合計量が上記範囲となることが好ましい。 The content of the polyacetal resin in the resin composition of the present embodiment is preferably 90% by mass or more, more preferably 93% by mass or more, and further preferably 95% by mass or more in the resin composition. preferable. By setting the value to the lower limit or more, the shape of the thin wall tends to be maintained more effectively. The content of the polyacetal resin is preferably 99% by mass or less in the resin composition. By setting the value to the upper limit or less, it tends to be possible to achieve better light-shielding property with a thin wall.
The resin composition of the present embodiment may contain only one type of polyacetal resin, or may contain two or more types of polyacetal resin. When two or more kinds are contained, it is preferable that the total amount is within the above range.
＜カーボンブラック＞
　本実施形態の樹脂組成物は、カーボンブラックを含む。カーボンブラックを含むことにより、遮光性に優れた成形体が得られる。
　本実施形態で用いられるカーボンブラックとしては、例えばファーネスブラック、アセチレンブラック、チャネルブラック、油煙ブラック（ランプブラック）などを用いることができる。 <Carbon black>
The resin composition of the present embodiment contains carbon black. By containing carbon black, a molded product having excellent light-shielding properties can be obtained.
As the carbon black used in the present embodiment, for example, furnace black, acetylene black, channel black, oil smoke black (lamp black) and the like can be used.
　カーボンブラックの平均粒径は特に限定されるものではないが、５ｎｍ以上であることが好ましく、１０ｎｍ以上であることがより好ましく、１５ｎｍ以上であることがさらに好ましい。前記下限値以上とすることにより、カーボンブラックの分散性がより向上する傾向にある。また、カーボンブラックの平均粒径は、５０ｎｍ以下であることが好ましく、４０ｎｍ以下であることがより好ましく、３０ｎｍ以下であることがさらに好ましく、２５ｎｍ以下であることが一層好ましい。前記上限値以下とすることにより、遮光性がより向上する傾向にある。ここで、平均粒径は、走査型電子顕微鏡を用いて観察した複数個のカーボンブラックの粒径の平均値を言う。 The average particle size of carbon black is not particularly limited, but is preferably 5 nm or more, more preferably 10 nm or more, and further preferably 15 nm or more. By setting the value to the lower limit or higher, the dispersibility of carbon black tends to be further improved. The average particle size of carbon black is preferably 50 nm or less, more preferably 40 nm or less, further preferably 30 nm or less, and even more preferably 25 nm or less. By setting the value to the upper limit or less, the light-shielding property tends to be further improved. Here, the average particle size refers to the average value of the particle sizes of a plurality of carbon blacks observed using a scanning electron microscope.
　本実施形態の樹脂組成物におけるカーボンブラックの含有量は、ポリアセタール樹脂１００質量部に対し、１．５質量部超であることが好ましい。前記下限値以上とすることにより、遮光性がより向上する傾向にある。また、前記カーボンブラックの含有量は、ポリアセタール樹脂１００質量部に対し、９質量部以下であることが好ましく、６質量部以下であることがより好ましく、４質量部以下であることがさらに好ましく、３質量部以下であることが一層好ましい。前記上限値以下とすることにより、薄肉成形に必要な流動性がより効果的に維持される傾向にある。
　本実施形態の樹脂組成物は、カーボンブラックを１種のみ含んでいてもよいし、２種以上含んでいてもよい。２種以上含む場合、合計量が上記範囲となることが好ましい。 The content of carbon black in the resin composition of the present embodiment is preferably more than 1.5 parts by mass with respect to 100 parts by mass of the polyacetal resin. By setting the value to the lower limit or more, the light-shielding property tends to be further improved. Further, the content of the carbon black is preferably 9 parts by mass or less, more preferably 6 parts by mass or less, and further preferably 4 parts by mass or less with respect to 100 parts by mass of the polyacetal resin. It is more preferably 3 parts by mass or less. By setting the value to the upper limit or less, the fluidity required for thin-wall molding tends to be more effectively maintained.
The resin composition of the present embodiment may contain only one type of carbon black, or may contain two or more types of carbon black. When two or more kinds are contained, it is preferable that the total amount is within the above range.
＜分散剤＞
　本実施形態の樹脂組成物は、分散剤を含む。分散剤を含むことにより、カーボンブラックをより効果的に分散させ、より遮光性に優れた成形体が得られる。
　分散剤は、カーボンブラックをポリアセタール樹脂中に分散させ得るものであれば特に限定されないが、ポリオレフィンワックス、脂肪酸、脂肪酸アミド、ポリアルキレングリコールおよびシリコーンからなる群より選ばれる少なくとも１種を含むことが好ましい。
　前記分散剤の一実施形態は、脂肪酸アミドを含むことである。
　前記分散剤の他の一実施形態は、シリコーンを含むことである。
　前記分散剤の他の一実施形態は、脂肪族アミドおよびシリコーンを含むことである。
　上記分散剤を用いることにより、成形体の摺動性をより向上させることができる。さらに、本実施形態においては、ポリオレフィンワックス、脂肪酸、脂肪酸アミド、ポリアルキレングリコールおよびシリコーンからなる群より選ばれる少なくとも２種以上（好ましくは２～４種、より好ましくは３種）の組合せが好ましい。２種以上の組合せとすることにより、より摺動性に優れた成形体が得られる傾向にある。本実施形態の樹脂組成物においては、前記分散剤がポリオレフィンワックス、脂肪酸、脂肪酸アミド、ポリアルキレングリコールおよびシリコーンからなる群より選ばれる少なくとも２種を含むことが好ましく、ポリオレフィンワックス、脂肪酸アミドおよびシリコーンの混合物を用いることがさらに好ましい。 <Dispersant>
The resin composition of the present embodiment contains a dispersant. By containing the dispersant, carbon black can be dispersed more effectively, and a molded product having more excellent light-shielding property can be obtained.
The dispersant is not particularly limited as long as it can disperse carbon black in the polyacetal resin, but preferably contains at least one selected from the group consisting of polyolefin wax, fatty acid, fatty acid amide, polyalkylene glycol and silicone. ..
One embodiment of the dispersant is to include a fatty acid amide.
Another embodiment of the dispersant is to include silicone.
Another embodiment of the dispersant is comprising an aliphatic amide and a silicone.
By using the above dispersant, the slidability of the molded product can be further improved. Further, in the present embodiment, a combination of at least two or more (preferably 2 to 4, more preferably 3) selected from the group consisting of polyolefin wax, fatty acid, fatty acid amide, polyalkylene glycol and silicone is preferable. By combining two or more types, a molded product having more excellent slidability tends to be obtained. In the resin composition of the present embodiment, the dispersant preferably contains at least two kinds selected from the group consisting of polyolefin wax, fatty acid, fatty acid amide, polyalkylene glycol and silicone, and the dispersant of polyolefin wax, fatty acid amide and silicone. It is more preferred to use a mixture.
　ポリオレフィンワックスとしては、ポリエチレンワックスおよびポリプロピレンワックスなどが挙げられる。 Examples of the polyolefin wax include polyethylene wax and polypropylene wax.
　脂肪酸としては、例えば、ステアリン酸、オレイン酸、オクタン酸、ラウリル酸、リシノール酸、ベヘン酸等の高級脂肪酸が挙げられる。 Examples of fatty acids include higher fatty acids such as stearic acid, oleic acid, octanoic acid, lauric acid, ricinoleic acid, and behenic acid.
　脂肪酸アミドは、高級脂肪酸および／または多塩基酸とジアミンとの脱水反応によって得られる化合物である。ここで、高級脂肪酸としては、炭素数１６以上、例えば炭素数１６～３０の飽和脂肪族モノカルボン酸が好ましく、具体的には、パルミチン酸、ステアリン酸、ベヘン酸、モンタン酸等が挙げられる。多塩基酸としては、二塩基酸以上のカルボン酸で、例えば、マロン酸、コハク酸、アジピン酸、セバシン酸、ピメリン酸、アゼライン酸等の脂肪族ジカルボン酸類およびフタル酸、テレフタル酸等の芳香族ジカルボン酸並びにシクロヘキシルジカルボン酸、シクロヘキシルコハク酸等の脂環族ジカルボン酸等が挙げられる。ジアミンとしては、例えば、エチレンジアミン、１，３－ジアミノプロパン、１，４－ジアミノブタン、ヘキサメチレンジアミン、メタキシリレンジアミン、トリレンジアミン、パラキシリレンジアミン、フェニレンジアミン、イソホロンジアミン等が挙げられる。脂肪酸アミドの具体例としては、ステアリルアミド、ベヘニルアミド、モンタニルアミド、メチレンビスステアリルアミド、エチレンビスステアリルアミド等が挙げられる。 Fatty acid amide is a compound obtained by dehydration reaction between higher fatty acid and / or polybasic acid and diamine. Here, as the higher fatty acid, a saturated aliphatic monocarboxylic acid having 16 or more carbon atoms, for example, 16 to 30 carbon atoms is preferable, and specific examples thereof include palmitic acid, stearic acid, behenic acid, and montanic acid. The polybasic acid is a carboxylic acid of dibasic acid or more, for example, aliphatic dicarboxylic acids such as malonic acid, succinic acid, adipic acid, sebacic acid, pimelli acid, and azelaic acid, and aromatic acids such as phthalic acid and terephthalic acid. Examples thereof include dicarboxylic acids and alicyclic dicarboxylic acids such as cyclohexyldicarboxylic acid and cyclohexylsuccinic acid. Examples of the diamine include ethylenediamine, 1,3-diaminopropane, 1,4-diaminobutane, hexamethylenediamine, m-xylylenediamine, tolylenediamine, paraxylylenediamine, phenylenediamine, isophoronediamine and the like. Specific examples of the fatty acid amide include stearylamide, behenylamide, montanylamide, methylenebisstearylamide, ethylenebisstearylamide and the like.
　ポリアルキレングリコールとしては、ポリメチレングリコール、ポリエチレングリコール、ポリプロピレングリコール、ポリブチレングリコール、ポリペンチレングリコール、ポリへキシレングリコール、ポリヘプチレングリコール、ポリオクチレングリコール、ポリノニレングリコール、ポリデシレングリコールなどが挙げられる。 Examples of polyalkylene glycols include polymethylene glycol, polyethylene glycol, polypropylene glycol, polybutylene glycol, polypentylene glycol, polyhexylene glycol, polyheptylene glycol, polyoctylene glycol, polynonylene glycol, and polydecylene glycol. And so on.
　シリコーンとしては、油、ゴム、樹脂などの性状を有するシリコーン油、シリコーンゴム、シリコーン樹脂、金属石ケン等を添加したシリコーングリスなどが挙げられる。シリコーンの具体例としては、例えば、ポリジメチルシロキサン、ポリジメチルシロキサンのメチル基の一部がフェニル基と置換されたオルガノシロキサン、ポリジメチルシロキサンのメチル基の一部が水素や炭素数２以上のアルキル基と置換されたオルガノシロキサン、ポリジメチルシロキサンのメチル基の一部がハロゲン化フェニル基と置換されたオルガノシロキサン、ポリジメチルシロキサンのメチル基の一部がフルオロエステル基と置換されたオルガノシロキサン、エポキシ変性オルガノシロキサン、アミノ変性オルガノシロキサン、アルコール変性オルガノシロキサン、アルキルアラルキルオルガノシロキサン、ポリエーテル変性オルガノシロキサンなどが挙げられる。 Examples of silicone include silicone oil having properties such as oil, rubber, and resin, silicone rubber, silicone resin, and silicone grease to which metal soap and the like are added. Specific examples of silicone include polydimethylsiloxane, organosiloxane in which part of the methyl group of polydimethylsiloxane is replaced with a phenyl group, and alkyl in which part of the methyl group of polydimethylsiloxane is hydrogen or having 2 or more carbon atoms. Organosiloxane replaced with a group, organosiloxane with a part of the methyl group of polydimethylsiloxane replaced with a halogenated phenyl group, organosiloxane with a part of the methyl group of polydimethylsiloxane replaced with a fluoroester group, epoxy Examples thereof include modified organosiloxanes, amino-modified organosiloxanes, alcohol-modified organosiloxanes, alkylaralkyl organosiloxanes, and polyether-modified organosiloxanes.
　シリコーンは、２５℃において５０万ｃＳｔ以上の動粘度を有することが好ましい。２５℃における動粘度が５０万ｃＳｔ以上のシリコーンを用いることにより、得られる成形体の外観がより良好となり、より高い摺動特性を維持させることができる。前記動粘度の上限は特に定めるものではないが、例えば、２００万ｃＳｔ以下であることが好ましい。 Silicone preferably has a kinematic viscosity of 500,000 cSt or more at 25 ° C. By using a silicone having a kinematic viscosity of 500,000 cSt or more at 25 ° C., the appearance of the obtained molded product can be improved and higher sliding characteristics can be maintained. The upper limit of the kinematic viscosity is not particularly specified, but is preferably 2 million cSt or less, for example.
　本実施形態の樹脂組成物における分散剤の含有量は、ポリアセタール樹脂１００質量部に対し、０．５質量部以上であることが好ましく、０．７質量部以上であることがより好ましく、０．８質量部以上であることがさらに好ましい。前記下限値以上とすることにより、カーボンブラックの分散性がより向上する傾向にある。また、前記分散剤の含有量は、ポリアセタール樹脂１００質量部に対し、７．０質量部以下であることが好ましく、６．０質量部以下であることがより好ましく、４．０質量部以下であることがさらに好ましく、２．０質量部以下であることが一層好ましい。前記上限値以下とすることにより、ポリアセタール樹脂が本来的に有している強度を効果的に維持できる傾向にある。
　本実施形態の樹脂組成物は、分散剤を１種のみ含んでいてもよいし、２種以上含んでいてもよい。２種以上含む場合、合計量が上記範囲となることが好ましい。 The content of the dispersant in the resin composition of the present embodiment is preferably 0.5 parts by mass or more, more preferably 0.7 parts by mass or more, and 0. It is more preferably 8 parts by mass or more. By setting the value to the lower limit or higher, the dispersibility of carbon black tends to be further improved. The content of the dispersant is preferably 7.0 parts by mass or less, more preferably 6.0 parts by mass or less, and 4.0 parts by mass or less with respect to 100 parts by mass of the polyacetal resin. It is more preferably 2.0 parts by mass or less. By setting the value to the upper limit or less, the strength inherent in the polyacetal resin tends to be effectively maintained.
The resin composition of the present embodiment may contain only one kind of dispersant, or may contain two or more kinds of dispersants. When two or more kinds are contained, it is preferable that the total amount is within the above range.
　本実施形態の樹脂組成物におけるカーボンブラックおよび分散剤の合計含有量は、ポリアセタール樹脂１００質量部に対し、２．０質量部超であり、２．５質量部以上であることが好ましく、２．８質量部以上であることがより好ましい。前記下限値以上とすることにより、遮光性がより向上する傾向にある。また、前記カーボンブラックおよび分散剤の合計含有量は、ポリアセタール樹脂１００質量部に対し、１０．０質量部以下であり、８．０質量部以下であることが好ましく、６．０質量部以下であることがより好ましく、５．０質量部以下であることがさらに好ましく、４．０質量部以下であることが一層好ましい。前記上限値以下とすることにより、ポリアセタール樹脂が本来的に有している強度をより効果的に発揮させることができる。 The total content of carbon black and the dispersant in the resin composition of the present embodiment is more than 2.0 parts by mass and preferably 2.5 parts by mass or more with respect to 100 parts by mass of the polyacetal resin. It is more preferably 8 parts by mass or more. By setting the value to the lower limit or more, the light-shielding property tends to be further improved. The total content of the carbon black and the dispersant is 10.0 parts by mass or less, preferably 8.0 parts by mass or less, and 6.0 parts by mass or less with respect to 100 parts by mass of the polyacetal resin. It is more preferably 5.0 parts by mass or less, further preferably 4.0 parts by mass or less. By setting the value to the upper limit or less, the strength inherent in the polyacetal resin can be more effectively exhibited.
　さらに、本実施形態の樹脂組成物においては、カーボンブラックおよび分散剤の合計量中のカーボンブラックの割合が６０質量％超であり、６１質量％以上であることが好ましく、６２質量％以上であることがより好ましい。前記下限値以上とすることにより、遮光性がより向上する傾向にある。また、前記カーボンブラックおよび分散剤の合計量中のカーボンブラックの割合は、１００質量％未満であり、９０質量％以下であることが好ましく、８０質量％以下であることがより好ましく、７５質量％以下であることがさらに好ましい。前記上限値以下とすることにより、遮光性を確保しつつ、薄肉の形状をより効果的に維持できる傾向にある。 Further, in the resin composition of the present embodiment, the ratio of carbon black to the total amount of carbon black and the dispersant is more than 60% by mass, preferably 61% by mass or more, and preferably 62% by mass or more. Is more preferable. By setting the value to the lower limit or more, the light-shielding property tends to be further improved. The proportion of carbon black in the total amount of the carbon black and the dispersant is less than 100% by mass, preferably 90% by mass or less, more preferably 80% by mass or less, and 75% by mass. The following is more preferable. By setting the value to the upper limit or less, there is a tendency that the shape of the thin wall can be maintained more effectively while ensuring the light-shielding property.
＜その他の成分＞
　本実施形態の樹脂組成物には、上記各成分以外の他の成分を含んでいてもよい。具体的には、他の成分として、無機充填剤、熱安定剤、酸化防止剤、耐候安定剤、耐光安定剤、紫外線吸収剤、結晶核剤、帯電防止剤、抗菌剤等が挙げられる。これらは単独でまたは２種以上を組み合せて用いることができる。
　また、本実施形態における樹脂組成物は、無機充填剤を実質的に含まない構成とすることができる。実質的に含まないとは、本実施形態における樹脂組成物中の無機充填剤の含有量が樹脂組成物の１質量％未満であることをいう。
　本実施形態の樹脂組成物は、ポリアセタール樹脂、カーボンブラックおよび分散剤と、必要に応じ配合されるその他の成分の合計が１００質量％となるように配合される。また、ポリアセタール樹脂、カーボンブラックおよび分散剤の合計量が樹脂組成物の９５～１００質量％を占めることが好ましく、９９～１００質量％を占めることがより好ましい。 <Other ingredients>
The resin composition of the present embodiment may contain components other than the above-mentioned components. Specific examples of other components include inorganic fillers, heat stabilizers, antioxidants, weather-resistant stabilizers, light-resistant stabilizers, ultraviolet absorbers, crystal nucleating agents, antistatic agents, antibacterial agents and the like. These can be used alone or in combination of two or more.
Further, the resin composition in the present embodiment can be configured to be substantially free of an inorganic filler. The term "substantially free" means that the content of the inorganic filler in the resin composition in the present embodiment is less than 1% by mass of the resin composition.
The resin composition of the present embodiment is blended so that the total of the polyacetal resin, carbon black and the dispersant and other components to be blended as necessary is 100% by mass. Further, the total amount of the polyacetal resin, carbon black and the dispersant preferably occupies 95 to 100% by mass, and more preferably 99 to 100% by mass of the resin composition.
＜樹脂組成物の製造方法＞
　本実施形態の樹脂組成物の製造方法は特に限定されず、樹脂組成物の調製法として従来から知られた各種の方法により調製することができる。例えば、（１）樹脂組成物を構成する全成分を混合し、これを押出機に供給して溶融混練し、ペレット状の組成物を得る方法、（２）樹脂組成物を構成する成分の一部を押出機の主フィード口から、残余成分をサイドフィード口から供給して溶融混練し、ペレット状の組成物を得る方法、（３）押出し等により一旦組成の異なるペレットを調製し、そのペレットを混合して所定の組成に調整する方法、（４）ポリアセタール樹脂のペレットまたは粉砕物に所定量の配合成分を混合するか、ポリアセタール樹脂のペレットまたは粉砕物の表面に所定量の配合成分をコーティングして所定の樹脂組成物を得る方法などが採用できる。 <Manufacturing method of resin composition>
The method for producing the resin composition of the present embodiment is not particularly limited, and the resin composition can be prepared by various methods conventionally known as a method for preparing the resin composition. For example, (1) a method of mixing all the components constituting the resin composition, supplying the mixture to an extruder and melt-kneading the mixture to obtain a pellet-shaped composition, and (2) one of the components constituting the resin composition. A method of supplying a portion from the main feed port of the extruder and melt-kneading the residual components from the side feed port to obtain a pellet-shaped composition, (3) once preparing pellets having different compositions by extrusion or the like, and then pelleting the pellets. (4) Polyacetal resin pellets or crushed material are mixed with a predetermined amount of compounding ingredients, or the surface of polyacetal resin pellets or crushed material is coated with a predetermined amount of compounding ingredients. Then, a method of obtaining a predetermined resin composition or the like can be adopted.
＜樹脂組成物の特性・物性＞
　本実施形態の樹脂組成物は、ＭＶＲが高めである。具体的には、樹脂組成物の１９０℃、荷重２．１６ｋｇ重の条件で測定されたＭＶＲが５０ｃｍ３／１０分超であり、５５ｃｍ３／１０分以上であることが好ましく、６０ｃｍ３／１０分超であることがより好ましく、６１ｃｍ３／１０分以上であることがさらに好ましく、６２ｃｍ３／１０分以上であることが一層好ましい。前記下限値以上とすることにより、流動性がより向上する傾向にある。前記ＭＶＲは、１００ｃｍ３／１０分未満であり、９０ｃｍ３／１０分以下であることが好ましく、８０ｃｍ３／１０分以下であることがより好ましい。前記上限値以下とすることにより、薄肉の形状をより効果的に維持できる傾向にある。
　ＭＶＲは、後述する実施例の記載に従って測定される。 <Characteristics and physical characteristics of resin composition>
The resin composition of the present embodiment has a high MVR. Specifically, the MVR of the resin composition measured under the conditions of 190 ° C. and a load of 2.16 kg is preferably more than 50 cm 3/10 minutes, preferably 55 cm 3/10 minutes or more, and is preferably 60 cm 3/10 . It is more preferably more than a minute, more preferably 61 cm 3/10 minutes or more, and even more preferably 62 cm 3/10 minutes or more. By setting the value to the lower limit or higher, the liquidity tends to be further improved. The MVR is less than 100 cm 3/10 minutes, preferably 90 cm 3/10 minutes or less, and more preferably 80 cm 3/10 minutes or less. By setting the value to the upper limit or less, the shape of the thin wall tends to be maintained more effectively.
MVR is measured according to the description of Examples described later.
　本実施形態の樹脂組成物は、遮光性に優れていることが好ましい。具体的には、樹脂組成物を０．０５ｍｍの厚さに成形したときのＪＩＳ－Ｋ－７１３６に従って測定した全光線透過率が、２％以下であることが好ましく、１．５％以下であることがより好ましく、１％以下であることがさらに好ましい。前記全光線透過率の下限値は、０％が好ましい。
　全光線透過率は、後述する実施例の記載に従って測定される。 The resin composition of the present embodiment is preferably excellent in light-shielding property. Specifically, the total light transmittance measured according to JIS-K-7136 when the resin composition is molded to a thickness of 0.05 mm is preferably 2% or less, preferably 1.5% or less. More preferably, it is more preferably 1% or less. The lower limit of the total light transmittance is preferably 0%.
The total light transmittance is measured according to the description of Examples described later.
＜樹脂組成物の用途および成形体＞
　本実施形態には、本実施形態の樹脂組成物から形成された成形体も含まれる。本実施形態における成形体は、遮光性に優れ、かつ、薄肉成形体とできる。本実施形態の成形体は、成形体の最薄肉部の厚さを０．１ｍｍ以下とすることができ、さらには、０．０７５ｍｍ以下とすることもできる。前記最薄肉部の厚さの下限値は、０．０１ｍｍ以上が実際的であり、０．０２ｍｍ以上であってもよい。
　本実施形態の樹脂組成物は、射出成形、押出成形、圧縮成形、ブロー成形、真空成形などの公知の成形方法により成形可能である。 <Uses of resin compositions and molded products>
The present embodiment also includes a molded product formed from the resin composition of the present embodiment. The molded product in the present embodiment has excellent light-shielding properties and can be a thin-walled molded product. In the molded product of the present embodiment, the thickness of the thinnest portion of the molded product can be 0.1 mm or less, and further can be 0.075 mm or less. The lower limit of the thickness of the thinnest portion is practically 0.01 mm or more, and may be 0.02 mm or more.
The resin composition of the present embodiment can be molded by a known molding method such as injection molding, extrusion molding, compression molding, blow molding, or vacuum molding.
　本実施形態の樹脂組成物および成形体は、自動車部品、電気・電子部品、精密機械部品、建材・配管部品、日用品、化粧品用部品、医療用機器部品などに好適に使用できるが、デジタル機器部品に好ましく用いられ、デジタルカメラの絞りばねに特に好ましく用いられる。 The resin composition and molded body of the present embodiment can be suitably used for automobile parts, electric / electronic parts, precision machine parts, building materials / piping parts, daily necessities, cosmetic parts, medical equipment parts, and the like, but digital equipment parts. It is preferably used for the aperture spring of a digital camera.
　以下に実施例を挙げて本発明をさらに具体的に説明する。以下の実施例に示す材料、使用量、割合、処理内容、処理手順等は、本発明の趣旨を逸脱しない限り、適宜、変更することができる。従って、本発明の範囲は以下に示す具体例に限定されるものではない。
　実施例で用いた測定機器等が廃番等により入手困難な場合、他の同等の性能を有する機器を用いて測定することができる。 Hereinafter, the present invention will be described in more detail with reference to examples. The materials, amounts used, ratios, treatment contents, treatment procedures, etc. shown in the following examples can be appropriately changed as long as they do not deviate from the gist of the present invention. Therefore, the scope of the present invention is not limited to the specific examples shown below.
If the measuring device or the like used in the examples is difficult to obtain due to a discontinued number or the like, measurement can be performed using another device having the same performance.
１．原料
ポリアセタール樹脂（Ａ１）：
トリオキサンと１，３－ジオキソランとを、オキシエチレン基の割合がオキシメチレン基１００モル％に対して１．４モル％となるように共重合して得られたオキシメチレンコポリマーであって、ＭＶＲ（１９０℃、２．１６ｋｇ重）が７５ｃｍ３／１０分であるオキシメチレンコポリマー
ポリアセタール樹脂（Ａ２）：
トリオキサンと１，３－ジオキソランとを、オキシエチレン基の割合がオキシメチレン基１００モル％に対して１．４モル％となるように共重合して得られたオキシメチレンコポリマーであって、ＭＶＲ（１９０℃、２．１６ｋｇ重）が４５ｃｍ３／１０分であるオキシメチレンコポリマー 1. 1. Raw material polyacetal resin (A1):
An oximethylene copolymer obtained by copolymerizing trioxane and 1,3-dioxolane so that the ratio of oxyethylene groups is 1.4 mol% with respect to 100 mol% of oxymethylene groups, which is an MVR ( Oxymethylene copolymer polyacetal resin (A2): 190 ° C., 2.16 kg weight) is 75 cm 3/10 min.
An oximethylene copolymer obtained by copolymerizing trioxane and 1,3-dioxolane so that the ratio of oxyethylene groups is 1.4 mol% with respect to 100 mol% of oxymethylene groups, which is an MVR ( Oxymethylene copolymer at 190 ° C., 2.16 kg weight) at 45 cm 3/10 min
カーボンブラック（Ｂ）：
ファーネスブラック、商品名「Ｒａｖｅｎ　ＰＦＥＢ」、平均粒径２１ｎｍ、コロンビヤンカーボン社製 Carbon black (B):
Furness Black, trade name "Raven PFEB", average particle size 21 nm, manufactured by Colombian Carbon Co., Ltd.
分散剤（Ｃ）
エチレンビスステアリルアミド（Ｃ１）：
商品名「ＥＢ－ＦＦ」、花王社製
ポリエチレンワックス（Ｃ２）：
商品名「ハイワックス７２０Ｐ」、三井化学社製
シリコーン（Ｃ３）：
２５℃における動粘度：１００万ｃＳｔのシリコーン Dispersant (C)
Ethylene bisstearylamide (C1):
Product name "EB-FF", Kao polyethylene wax (C2):
Product name "High Wax 720P", Silicone (C3) manufactured by Mitsui Chemicals, Inc .:
Kinematic viscosity at 25 ° C: 1 million cSt silicone
２．実施例１～４、比較例１～４
＜コンパウンド＞
　ポリアセタール樹脂（Ａ）、カーボンブラック（Ｂ）および分散剤（Ｃ）を表１に示す配合割合で、川田製作所社製スーパーミキサーを用いて均一に混合したのち、２軸押出機（池貝鉄工社製ＰＣＭ－２９、スクリュー径２９ｍｍ）を用いて、スクリュー回転数１２０ｒｐｍ、シリンダー設定温度１９０℃の条件下で溶融混練し、ストランドに押出し、ペレタイザーにてカットすることで樹脂組成物（ペレット）を製造した。 2. 2. Examples 1 to 4, Comparative Examples 1 to 4
<Compound>
Polyacetal resin (A), carbon black (B) and dispersant (C) are uniformly mixed using a super mixer manufactured by Kawada Seisakusho Co., Ltd. in the blending ratios shown in Table 1, and then a twin-screw extruder (manufactured by Ikekai Iron Works Co., Ltd.). Using PCM-29 (screw diameter 29 mm), a resin composition (pellet) was produced by melt-kneading under the conditions of a screw rotation speed of 120 rpm and a cylinder set temperature of 190 ° C., extruding into a strand, and cutting with a pelletizer. ..
＜樹脂および樹脂組成物のＭＶＲ＞
　ポリアセタール樹脂および上記で得られた樹脂組成物（ペレット）のＭＶＲ（単位：ｃｍ３／１０分）は、ＩＳＯ１１３３に準拠して、１９０℃、荷重２．１６ｋｇ重の条件で測定した。樹脂組成物（ペレット）のＭＶＲの結果は表１に示す。 <MVR of resin and resin composition>
The MVR (unit: cm 3/10 min) of the polyacetal resin and the resin composition (pellet) obtained above was measured at 190 ° C. and a load of 2.16 kg in accordance with ISO1133. The results of MVR of the resin composition (pellets) are shown in Table 1.
＜遮光性（全光線透過率）＞
　上記で得られた樹脂組成物（ペレット）を８０℃で３時間乾燥した後、プレス機を用いてプレス加工を行い、厚さ０．０５ｍｍ×２０ｍｍ×２０ｍｍの試験シートを用意した。得られた試験シートについて、ヘーズメーターを用い、ＪＩＳ－Ｋ－７１３６に従って全光線透過率（単位：％）を測定した。結果を表１に示す。
　プレス機は、製品名「ミニテストプレス」、東洋精機社製を用いた。ヘーズメーターは、日本電色社製、ＮＤＨ４０００を用いた。 <Light-shielding property (total light transmittance)>
The resin composition (pellet) obtained above was dried at 80 ° C. for 3 hours and then pressed using a press machine to prepare a test sheet having a thickness of 0.05 mm × 20 mm × 20 mm. The total light transmittance (unit:%) of the obtained test sheet was measured according to JIS-K-7136 using a haze meter. The results are shown in Table 1.
The press machine used was the product name "Mini Test Press" manufactured by Toyo Seiki Co., Ltd. As the haze meter, NDH4000 manufactured by Nippon Denshoku Co., Ltd. was used.
＜流動性＞
　樹脂組成物ペレットを８０℃で３時間乾燥した後、射出成形機（住友重機械工業株式会社製「ＳＥ３０ＤＵＺ」）を用いて、シリンダー温度１９５℃、金型温度８０℃の条件で射出成形し、１４５ｍｍ×１３ｍｍ×厚さ０．３ｍｍの平板を成形し、その際の流動性を確認した。
Ａ：流動性に優れていた
Ｂ：実用レベルであるが、Ａに比べ流動性が劣っていた
Ｃ：流動性が劣っていた（実用レベル外） <Liquidity>
The resin composition pellets were dried at 80 ° C. for 3 hours, and then injection molded using an injection molding machine (“SE30DUZ” manufactured by Sumitomo Heavy Industries, Ltd.) under the conditions of a cylinder temperature of 195 ° C. and a mold temperature of 80 ° C. A flat plate of 145 mm × 13 mm × thickness of 0.3 mm was formed, and the fluidity at that time was confirmed.
A: Excellent fluidity B: Practical level, but inferior in fluidity compared to A C: Inferior in fluidity (outside the practical level)
＜熱処理後の外観＞
　樹脂組成物ペレットを８０℃で３時間乾燥した後、射出成形機（芝浦機械社製「ＥＣ１００ＳＸ」）を用いて、シリンダー温度１９５℃、金型温度９０℃の条件で射出成形し、１００ｍｍ×１００ｍｍ×厚さ２．０ｍｍの平板を成形した。得られた平板について８０℃で１００時間熱処理を行い、熱処理後の平板の外観を観察した。
Ａ：平板の表面に異物が見られなかった
Ｂ：平板の表面にわずかに異物が見られた
Ｃ：平板の表面に大量に異物が見られた <Appearance after heat treatment>
After drying the resin composition pellets at 80 ° C. for 3 hours, injection molding was performed using an injection molding machine (“EC100SX” manufactured by Shibaura Machine Co., Ltd.) under the conditions of a cylinder temperature of 195 ° C. and a mold temperature of 90 ° C., and 100 mm × 100 mm. × A flat plate with a thickness of 2.0 mm was formed. The obtained flat plate was heat-treated at 80 ° C. for 100 hours, and the appearance of the flat plate after the heat treatment was observed.
A: No foreign matter was found on the surface of the flat plate B: A slight foreign matter was found on the surface of the flat plate C: A large amount of foreign matter was found on the surface of the flat plate
＜摺動性＞
　円筒型スラスト試験片を、シリンダー温度２００℃、金型温度８０℃で射出成形にて作製した。オリエンテック社製スラスト式摩擦摩耗試験機を用い、温度２３℃、湿度５０％雰囲気下で、面圧０．２５ＭＰａ、線速度０．１ｍ／秒で測定した。 <Sliding>
A cylindrical thrust test piece was produced by injection molding at a cylinder temperature of 200 ° C. and a mold temperature of 80 ° C. The measurement was carried out using a thrust type friction and wear tester manufactured by Orientec Co., Ltd. at a temperature of 23 ° C., a humidity of 50%, a surface pressure of 0.25 MPa, and a linear velocity of 0.1 m / sec.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　上記表において、「（Ｃ）の総量」とは、（Ｃ１）～（Ｃ３）の合計量（単位：質量部）を意味している。「（Ｂ）＋（Ｃ）の量」とは、（Ｂ）および（Ｃ１）～（Ｃ３）の合計量、すなわち、カーボンブラックおよび分散剤の合計量（単位：質量部）を意味している。従って、「｛（Ｂ）／［（Ｂ）＋（Ｃ）］｝×１００」は、カーボンブラックおよび分散剤の合計量中のカーボンブラックの割合（単位：質量％）を示している。
　上記結果から明らかなとおり、本発明の樹脂組成物（実施例１～４）から得られた成形体は、薄くても、遮光性に優れた成形体であった。さらに、本発明の樹脂組成物は流動性にも優れており、薄肉成形体の成形性に優れていた。
　一方、カーボンブラックおよび分散剤の含有量が本発明の範囲を満たさない場合（比較例１）、遮光性が低くなってしまった。また、樹脂組成物のＭＶＲが本発明の範囲を満たさない場合、流動性がやや劣っており、デジタルカメラの絞りばねのような薄肉成形体に用いるには、流動性が不足していた（比較例２）。
　また、（Ｂ）／（Ｂ）＋（Ｃ）×１００が６０質量％以下の場合、全光線透過率が高かった（比較例３）。
　カーボンブラックの含有量が多い場合、流動性が低下してしまった（比較例４）。 In the above table, the "total amount of (C)" means the total amount (unit: parts by mass) of (C1) to (C3). The "amount of (B) + (C)" means the total amount of (B) and (C1) to (C3), that is, the total amount of carbon black and the dispersant (unit: parts by mass). .. Therefore, "{(B) / [(B) + (C)]} x 100" indicates the ratio (unit: mass%) of carbon black to the total amount of carbon black and the dispersant.
As is clear from the above results, the molded product obtained from the resin compositions of the present invention (Examples 1 to 4) was a molded product having excellent light-shielding properties even though it was thin. Further, the resin composition of the present invention is also excellent in fluidity and is excellent in moldability of a thin-walled molded product.
On the other hand, when the contents of carbon black and the dispersant do not meet the scope of the present invention (Comparative Example 1), the light-shielding property is lowered. Further, when the MVR of the resin composition does not meet the scope of the present invention, the fluidity is slightly inferior, and the fluidity is insufficient for use in a thin-walled molded body such as a draw spring of a digital camera (comparison). Example 2).
Further, when (B) / (B) + (C) × 100 was 60% by mass or less, the total light transmittance was high (Comparative Example 3).
When the content of carbon black was high, the fluidity decreased (Comparative Example 4).

Claims (20)

  1. ポリアセタール樹脂１００質量部に対し、
    カーボンブラックおよび分散剤を合計で２．０質量部超１０．０質量部以下の割合で含み、
    前記カーボンブラックおよび分散剤の合計量中のカーボンブラックの割合が６０質量％超１００質量％未満である樹脂組成物であって、
    樹脂組成物の１９０℃、荷重２．１６ｋｇ重の条件で測定されたメルトボリュームレイトが５０ｃｍ３／１０分超１００ｃｍ３／１０分未満である、樹脂組成物。     For 100 parts by mass of polyacetal resin
    Contains carbon black and dispersant in a total ratio of more than 2.0 parts by mass and not more than 10.0 parts by mass.
    A resin composition in which the proportion of carbon black in the total amount of the carbon black and the dispersant is more than 60% by mass and less than 100% by mass.
    A resin composition having a melt volume rate of more than 50 cm 3/10 minutes and less than 100 cm 3/10 minutes measured under the conditions of 190 ° C. and a load of 2.16 kg.
  2. 前記樹脂組成物の１９０℃、荷重２．１６ｋｇ重の条件で測定されたメルトボリュームレイトが６０ｃｍ３／１０分超１００ｃｍ３／１０分未満である、請求項１に記載の樹脂組成物。 The resin composition according to claim 1, wherein the melt volume rate of the resin composition measured under the conditions of 190 ° C. and a load of 2.16 kg is more than 60 cm 3/10 minutes and less than 100 cm 3/10 minutes.
  3. 前記カーボンブラックの含有量が、ポリアセタール樹脂１００質量部に対し、１．５質量部超９質量部以下である、請求項１または２に記載の樹脂組成物。 The resin composition according to claim 1 or 2, wherein the content of the carbon black is more than 1.5 parts by mass and 9 parts by mass or less with respect to 100 parts by mass of the polyacetal resin.
  4. 前記カーボンブラックの含有量が、ポリアセタール樹脂１００質量部に対し、１．５質量部超６質量部以下である、請求項１または２に記載の樹脂組成物。 The resin composition according to claim 1 or 2, wherein the content of the carbon black is more than 1.5 parts by mass and 6 parts by mass or less with respect to 100 parts by mass of the polyacetal resin.
  5. 前記カーボンブラックの含有量が、ポリアセタール樹脂１００質量部に対し、１．５質量部超４質量部以下である、請求項１または２に記載の樹脂組成物。 The resin composition according to claim 1 or 2, wherein the content of the carbon black is more than 1.5 parts by mass and 4 parts by mass or less with respect to 100 parts by mass of the polyacetal resin.
  6. 前記分散剤がポリオレフィンワックス、脂肪酸、脂肪酸アミド、ポリアルキレングリコールおよびシリコーンからなる群より選ばれる少なくとも１種を含む、請求項１～５のいずれか１項に記載の樹脂組成物。 The resin composition according to any one of claims 1 to 5, wherein the dispersant contains at least one selected from the group consisting of polyolefin wax, fatty acid, fatty acid amide, polyalkylene glycol and silicone.
  7. 前記分散剤がポリオレフィンワックス、脂肪酸、脂肪酸アミド、ポリアルキレングリコールおよびシリコーンからなる群より選ばれる少なくとも２種を含む、請求項１～５のいずれか１項に記載の樹脂組成物。 The resin composition according to any one of claims 1 to 5, wherein the dispersant contains at least two kinds selected from the group consisting of polyolefin wax, fatty acid, fatty acid amide, polyalkylene glycol and silicone.
  8. 前記分散剤が脂肪酸アミドを含む、請求項６または７に記載の樹脂組成物。 The resin composition according to claim 6 or 7, wherein the dispersant contains a fatty acid amide.
  9. 前記分散剤がシリコーンを含む、請求項６～８のいずれか１項に記載の樹脂組成物。 The resin composition according to any one of claims 6 to 8, wherein the dispersant contains silicone.
  10. 前記分散剤が脂肪族アミドおよびシリコーンを含む、請求項７に記載の樹脂組成物。 The resin composition according to claim 7, wherein the dispersant contains an aliphatic amide and a silicone.
  11. 前記分散剤中の脂肪酸アミド量が、分散剤合計量に対して４０質量％以下である、請求項１～１０のいずれか１項に記載の樹脂組成物。 The resin composition according to any one of claims 1 to 10, wherein the amount of fatty acid amide in the dispersant is 40% by mass or less with respect to the total amount of the dispersant.
  12. 前記ポリアセタール樹脂の１９０℃、荷重２．１６ｋｇ重の条件で測定されたメルトボリュームレイトが４５ｃｍ３／１０分超１００ｃｍ３／１０分未満である、請求項１～１１のいずれか１項に記載の樹脂組成物。 13 . Resin composition.
  13. デジタルカメラの絞りばね用である、請求項１～１２のいずれか１項に記載の樹脂組成物。 The resin composition according to any one of claims 1 to 12, which is used for a diaphragm spring of a digital camera.
  14. 前記樹脂組成物を０．０５ｍｍの厚さに成形したときのＪＩＳ－Ｋ－７１３６に従って測定した全光線透過率が、２％以下である、請求項１～１３のいずれか１項に記載の樹脂組成物。 The resin according to any one of claims 1 to 13, wherein the total light transmittance measured according to JIS-K-7136 when the resin composition is molded to a thickness of 0.05 mm is 2% or less. Composition.
  15. 前記樹脂組成物を０．０５ｍｍの厚さに成形したときのＪＩＳ－Ｋ－７１３６に従って測定した全光線透過率が、１％以下である、請求項１～１３のいずれか１項に記載の樹脂組成物。 The resin according to any one of claims 1 to 13, wherein the total light transmittance measured according to JIS-K-7136 when the resin composition is molded to a thickness of 0.05 mm is 1% or less. Composition.
  16. 請求項１～１５のいずれか１項に記載の樹脂組成物から形成された成形体。 A molded product formed from the resin composition according to any one of claims 1 to 15.
  17. 前記成形体がデジタル機器部品である、請求項１６に記載の成形体。 The molded product according to claim 16, wherein the molded product is a digital device component.
  18. 前記成形体がデジタルカメラの絞りばねである、請求項１６に記載の成形体。 The molded body according to claim 16, wherein the molded body is a throttle spring of a digital camera.
  19. 前記成形体の最薄肉部の厚さが０．１ｍｍ以下である、請求項１６～１８のいずれか１項に記載の成形体。 The molded product according to any one of claims 16 to 18, wherein the thickness of the thinnest portion of the molded product is 0.1 mm or less.
  20. 前記成形体の最薄肉部の厚さが０．０７５ｍｍ以下である、請求項１６～１８のいずれか１項に記載の成形体。 The molded product according to any one of claims 16 to 18, wherein the thickness of the thinnest portion of the molded product is 0.075 mm or less.
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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5951937A (en) * 1982-09-16 1984-03-26 Polyplastics Co Polyacetal resin composition
JP2017014304A (en) * 2015-06-26 2017-01-19 三菱エンジニアリングプラスチックス株式会社 Polyacetal resin composition, molded body and digital device component
JP2020045405A (en) * 2018-09-18 2020-03-26 旭化成株式会社 Polyacetal resin composition and molding thereof

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5951937A (en) * 1982-09-16 1984-03-26 Polyplastics Co Polyacetal resin composition
JP2017014304A (en) * 2015-06-26 2017-01-19 三菱エンジニアリングプラスチックス株式会社 Polyacetal resin composition, molded body and digital device component
JP2020045405A (en) * 2018-09-18 2020-03-26 旭化成株式会社 Polyacetal resin composition and molding thereof

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