JP2018131618A - Magnetic foam and method of producing the same - Google Patents
Magnetic foam and method of producing the same Download PDFInfo
- Publication number
- JP2018131618A JP2018131618A JP2018022938A JP2018022938A JP2018131618A JP 2018131618 A JP2018131618 A JP 2018131618A JP 2018022938 A JP2018022938 A JP 2018022938A JP 2018022938 A JP2018022938 A JP 2018022938A JP 2018131618 A JP2018131618 A JP 2018131618A
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- JP
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- Prior art keywords
- magnetic
- foam
- weight
- particles
- resin
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 239000006260 foam Substances 0.000 title claims abstract description 124
- 238000000034 method Methods 0.000 title description 36
- 239000002245 particle Substances 0.000 claims abstract description 101
- 239000006249 magnetic particle Substances 0.000 claims abstract description 80
- 230000005484 gravity Effects 0.000 claims abstract description 51
- 229910000859 α-Fe Inorganic materials 0.000 claims abstract description 51
- 229920005992 thermoplastic resin Polymers 0.000 claims abstract description 35
- 229920005989 resin Polymers 0.000 claims abstract description 30
- 239000011347 resin Substances 0.000 claims abstract description 30
- 229920005672 polyolefin resin Polymers 0.000 claims abstract description 15
- PPBRXRYQALVLMV-UHFFFAOYSA-N Styrene Chemical compound C=CC1=CC=CC=C1 PPBRXRYQALVLMV-UHFFFAOYSA-N 0.000 claims abstract description 14
- 239000011342 resin composition Substances 0.000 claims abstract description 12
- 229920002725 thermoplastic elastomer Polymers 0.000 claims abstract description 7
- 238000004519 manufacturing process Methods 0.000 claims description 16
- 229910044991 metal oxide Inorganic materials 0.000 claims description 5
- 150000004706 metal oxides Chemical class 0.000 claims description 5
- 239000002131 composite material Substances 0.000 claims description 3
- 238000010097 foam moulding Methods 0.000 abstract description 5
- 229920001684 low density polyethylene Polymers 0.000 description 28
- 239000004702 low-density polyethylene Substances 0.000 description 28
- 239000004088 foaming agent Substances 0.000 description 24
- 239000004594 Masterbatch (MB) Substances 0.000 description 17
- 229910001035 Soft ferrite Inorganic materials 0.000 description 16
- 230000000052 comparative effect Effects 0.000 description 16
- 238000005187 foaming Methods 0.000 description 16
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 14
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 14
- 229910001047 Hard ferrite Inorganic materials 0.000 description 13
- 230000005415 magnetization Effects 0.000 description 13
- 239000000203 mixture Substances 0.000 description 12
- 239000000843 powder Substances 0.000 description 12
- 239000002994 raw material Substances 0.000 description 10
- 238000001816 cooling Methods 0.000 description 9
- 230000005389 magnetism Effects 0.000 description 9
- 239000002667 nucleating agent Substances 0.000 description 9
- NNPPMTNAJDCUHE-UHFFFAOYSA-N isobutane Chemical compound CC(C)C NNPPMTNAJDCUHE-UHFFFAOYSA-N 0.000 description 8
- 238000005259 measurement Methods 0.000 description 8
- 229920013716 polyethylene resin Polymers 0.000 description 8
- -1 polypropylene Polymers 0.000 description 8
- 239000000654 additive Substances 0.000 description 7
- 239000003795 chemical substances by application Substances 0.000 description 7
- 238000001125 extrusion Methods 0.000 description 6
- 239000011777 magnesium Substances 0.000 description 6
- 239000000463 material Substances 0.000 description 6
- 229910052751 metal Inorganic materials 0.000 description 6
- 239000002184 metal Substances 0.000 description 6
- 239000011230 binding agent Substances 0.000 description 5
- 238000007796 conventional method Methods 0.000 description 5
- 238000010304 firing Methods 0.000 description 5
- OFBQJSOFQDEBGM-UHFFFAOYSA-N n-pentane Natural products CCCCC OFBQJSOFQDEBGM-UHFFFAOYSA-N 0.000 description 5
- 239000000047 product Substances 0.000 description 5
- 239000011701 zinc Substances 0.000 description 5
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 4
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 description 4
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 4
- 229910045601 alloy Inorganic materials 0.000 description 4
- 239000000956 alloy Substances 0.000 description 4
- 229920001577 copolymer Polymers 0.000 description 4
- 235000014113 dietary fatty acids Nutrition 0.000 description 4
- 239000002270 dispersing agent Substances 0.000 description 4
- 239000005038 ethylene vinyl acetate Substances 0.000 description 4
- 239000000194 fatty acid Substances 0.000 description 4
- 229930195729 fatty acid Natural products 0.000 description 4
- 239000001282 iso-butane Substances 0.000 description 4
- 239000000696 magnetic material Substances 0.000 description 4
- 238000000465 moulding Methods 0.000 description 4
- 229920001200 poly(ethylene-vinyl acetate) Polymers 0.000 description 4
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 3
- 230000000996 additive effect Effects 0.000 description 3
- KRKNYBCHXYNGOX-UHFFFAOYSA-N citric acid Chemical compound OC(=O)CC(O)(C(O)=O)CC(O)=O KRKNYBCHXYNGOX-UHFFFAOYSA-N 0.000 description 3
- 238000004891 communication Methods 0.000 description 3
- 150000004665 fatty acids Chemical class 0.000 description 3
- 238000005227 gel permeation chromatography Methods 0.000 description 3
- 229930195733 hydrocarbon Natural products 0.000 description 3
- 239000003112 inhibitor Substances 0.000 description 3
- 238000002347 injection Methods 0.000 description 3
- 239000007924 injection Substances 0.000 description 3
- 238000001746 injection moulding Methods 0.000 description 3
- 238000004898 kneading Methods 0.000 description 3
- 239000006247 magnetic powder Substances 0.000 description 3
- 239000011572 manganese Substances 0.000 description 3
- 239000008188 pellet Substances 0.000 description 3
- 238000002360 preparation method Methods 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- RFFLAFLAYFXFSW-UHFFFAOYSA-N 1,2-dichlorobenzene Chemical compound ClC1=CC=CC=C1Cl RFFLAFLAYFXFSW-UHFFFAOYSA-N 0.000 description 2
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 2
- 239000004793 Polystyrene Substances 0.000 description 2
- 239000004372 Polyvinyl alcohol Substances 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- UIIMBOGNXHQVGW-DEQYMQKBSA-M Sodium bicarbonate-14C Chemical compound [Na+].O[14C]([O-])=O UIIMBOGNXHQVGW-DEQYMQKBSA-M 0.000 description 2
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 description 2
- 150000001338 aliphatic hydrocarbons Chemical class 0.000 description 2
- 150000001336 alkenes Chemical class 0.000 description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 2
- 229910000019 calcium carbonate Inorganic materials 0.000 description 2
- 239000001569 carbon dioxide Substances 0.000 description 2
- 229910002092 carbon dioxide Inorganic materials 0.000 description 2
- 239000002826 coolant Substances 0.000 description 2
- 238000009826 distribution Methods 0.000 description 2
- 238000000445 field-emission scanning electron microscopy Methods 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- IPCSVZSSVZVIGE-UHFFFAOYSA-N hexadecanoic acid Chemical compound CCCCCCCCCCCCCCCC(O)=O IPCSVZSSVZVIGE-UHFFFAOYSA-N 0.000 description 2
- 229920001903 high density polyethylene Polymers 0.000 description 2
- 239000004700 high-density polyethylene Substances 0.000 description 2
- 150000002430 hydrocarbons Chemical class 0.000 description 2
- 229910052742 iron Inorganic materials 0.000 description 2
- 230000001788 irregular Effects 0.000 description 2
- QWTDNUCVQCZILF-UHFFFAOYSA-N isopentane Chemical compound CCC(C)C QWTDNUCVQCZILF-UHFFFAOYSA-N 0.000 description 2
- 239000000314 lubricant Substances 0.000 description 2
- 229910052749 magnesium Inorganic materials 0.000 description 2
- 229920001179 medium density polyethylene Polymers 0.000 description 2
- 239000004701 medium-density polyethylene Substances 0.000 description 2
- IJDNQMDRQITEOD-UHFFFAOYSA-N n-butane Chemical compound CCCC IJDNQMDRQITEOD-UHFFFAOYSA-N 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- JRZJOMJEPLMPRA-UHFFFAOYSA-N olefin Natural products CCCCCCCC=C JRZJOMJEPLMPRA-UHFFFAOYSA-N 0.000 description 2
- 229920000620 organic polymer Polymers 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- 229910052760 oxygen Inorganic materials 0.000 description 2
- 229920002223 polystyrene Polymers 0.000 description 2
- 229920002451 polyvinyl alcohol Polymers 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- 239000002002 slurry Substances 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 239000002904 solvent Substances 0.000 description 2
- 239000000454 talc Substances 0.000 description 2
- 229910052623 talc Inorganic materials 0.000 description 2
- 238000003856 thermoforming Methods 0.000 description 2
- 239000010409 thin film Substances 0.000 description 2
- 150000003626 triacylglycerols Chemical class 0.000 description 2
- RNFJDJUURJAICM-UHFFFAOYSA-N 2,2,4,4,6,6-hexaphenoxy-1,3,5-triaza-2$l^{5},4$l^{5},6$l^{5}-triphosphacyclohexa-1,3,5-triene Chemical compound N=1P(OC=2C=CC=CC=2)(OC=2C=CC=CC=2)=NP(OC=2C=CC=CC=2)(OC=2C=CC=CC=2)=NP=1(OC=1C=CC=CC=1)OC1=CC=CC=C1 RNFJDJUURJAICM-UHFFFAOYSA-N 0.000 description 1
- WSSSPWUEQFSQQG-UHFFFAOYSA-N 4-methyl-1-pentene Chemical compound CC(C)CC=C WSSSPWUEQFSQQG-UHFFFAOYSA-N 0.000 description 1
- 229920000178 Acrylic resin Polymers 0.000 description 1
- 239000004925 Acrylic resin Substances 0.000 description 1
- ATRRKUHOCOJYRX-UHFFFAOYSA-N Ammonium bicarbonate Chemical compound [NH4+].OC([O-])=O ATRRKUHOCOJYRX-UHFFFAOYSA-N 0.000 description 1
- 239000004156 Azodicarbonamide Substances 0.000 description 1
- 229910001152 Bi alloy Inorganic materials 0.000 description 1
- BVKZGUZCCUSVTD-UHFFFAOYSA-M Bicarbonate Chemical class OC([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-M 0.000 description 1
- 239000004604 Blowing Agent Substances 0.000 description 1
- 229920000049 Carbon (fiber) Polymers 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 229910017518 Cu Zn Inorganic materials 0.000 description 1
- 229910017752 Cu-Zn Inorganic materials 0.000 description 1
- 229910017868 Cu—Ni—Co Inorganic materials 0.000 description 1
- 229910017881 Cu—Ni—Fe Inorganic materials 0.000 description 1
- 229910017943 Cu—Zn Inorganic materials 0.000 description 1
- 229910000976 Electrical steel Inorganic materials 0.000 description 1
- 239000004609 Impact Modifier Substances 0.000 description 1
- 229920010126 Linear Low Density Polyethylene (LLDPE) Polymers 0.000 description 1
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 1
- 229910018657 Mn—Al Inorganic materials 0.000 description 1
- 229910018054 Ni-Cu Inorganic materials 0.000 description 1
- 229910018481 Ni—Cu Inorganic materials 0.000 description 1
- 229910018605 Ni—Zn Inorganic materials 0.000 description 1
- 235000021314 Palmitic acid Nutrition 0.000 description 1
- 229930182556 Polyacetal Natural products 0.000 description 1
- 239000004743 Polypropylene Substances 0.000 description 1
- 229910001260 Pt alloy Inorganic materials 0.000 description 1
- 235000021355 Stearic acid Nutrition 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 1
- XTXRWKRVRITETP-UHFFFAOYSA-N Vinyl acetate Chemical compound CC(=O)OC=C XTXRWKRVRITETP-UHFFFAOYSA-N 0.000 description 1
- BZHJMEDXRYGGRV-UHFFFAOYSA-N Vinyl chloride Chemical compound ClC=C BZHJMEDXRYGGRV-UHFFFAOYSA-N 0.000 description 1
- 229910021536 Zeolite Inorganic materials 0.000 description 1
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 1
- 239000006096 absorbing agent Substances 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 230000001133 acceleration Effects 0.000 description 1
- 229920006243 acrylic copolymer Polymers 0.000 description 1
- 239000003570 air Substances 0.000 description 1
- 150000001298 alcohols Chemical class 0.000 description 1
- 150000001299 aldehydes Chemical class 0.000 description 1
- 229910000828 alnico Inorganic materials 0.000 description 1
- WNROFYMDJYEPJX-UHFFFAOYSA-K aluminium hydroxide Chemical compound [OH-].[OH-].[OH-].[Al+3] WNROFYMDJYEPJX-UHFFFAOYSA-K 0.000 description 1
- CEGOLXSVJUTHNZ-UHFFFAOYSA-K aluminium tristearate Chemical compound [Al+3].CCCCCCCCCCCCCCCCCC([O-])=O.CCCCCCCCCCCCCCCCCC([O-])=O.CCCCCCCCCCCCCCCCCC([O-])=O CEGOLXSVJUTHNZ-UHFFFAOYSA-K 0.000 description 1
- 229940063655 aluminum stearate Drugs 0.000 description 1
- 235000012538 ammonium bicarbonate Nutrition 0.000 description 1
- 239000001099 ammonium carbonate Substances 0.000 description 1
- 235000012501 ammonium carbonate Nutrition 0.000 description 1
- 230000002421 anti-septic effect Effects 0.000 description 1
- 239000012753 anti-shrinkage agent Substances 0.000 description 1
- 239000003429 antifungal agent Substances 0.000 description 1
- 229940121375 antifungal agent Drugs 0.000 description 1
- 239000003963 antioxidant agent Substances 0.000 description 1
- 229940064004 antiseptic throat preparations Drugs 0.000 description 1
- 239000002216 antistatic agent Substances 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 150000004945 aromatic hydrocarbons Chemical class 0.000 description 1
- 239000012298 atmosphere Substances 0.000 description 1
- XOZUGNYVDXMRKW-AATRIKPKSA-N azodicarbonamide Chemical compound NC(=O)\N=N\C(N)=O XOZUGNYVDXMRKW-AATRIKPKSA-N 0.000 description 1
- 235000019399 azodicarbonamide Nutrition 0.000 description 1
- 239000003899 bactericide agent Substances 0.000 description 1
- 239000000022 bacteriostatic agent Substances 0.000 description 1
- 229910052788 barium Inorganic materials 0.000 description 1
- DSAJWYNOEDNPEQ-UHFFFAOYSA-N barium atom Chemical compound [Ba] DSAJWYNOEDNPEQ-UHFFFAOYSA-N 0.000 description 1
- 239000011324 bead Substances 0.000 description 1
- 230000003115 biocidal effect Effects 0.000 description 1
- 239000003139 biocide Substances 0.000 description 1
- 230000003139 buffering effect Effects 0.000 description 1
- 239000001273 butane Substances 0.000 description 1
- 235000010216 calcium carbonate Nutrition 0.000 description 1
- CJZGTCYPCWQAJB-UHFFFAOYSA-L calcium stearate Chemical compound [Ca+2].CCCCCCCCCCCCCCCCCC([O-])=O.CCCCCCCCCCCCCCCCCC([O-])=O CJZGTCYPCWQAJB-UHFFFAOYSA-L 0.000 description 1
- 239000008116 calcium stearate Substances 0.000 description 1
- 235000013539 calcium stearate Nutrition 0.000 description 1
- 239000004917 carbon fiber Substances 0.000 description 1
- 150000004649 carbonic acid derivatives Chemical class 0.000 description 1
- 238000005660 chlorination reaction Methods 0.000 description 1
- 229910017052 cobalt Inorganic materials 0.000 description 1
- 239000010941 cobalt Substances 0.000 description 1
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 1
- 239000003086 colorant Substances 0.000 description 1
- 239000013065 commercial product Substances 0.000 description 1
- 239000000498 cooling water Substances 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- TVZPLCNGKSPOJA-UHFFFAOYSA-N copper zinc Chemical compound [Cu].[Zn] TVZPLCNGKSPOJA-UHFFFAOYSA-N 0.000 description 1
- 230000001186 cumulative effect Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 239000002781 deodorant agent Substances 0.000 description 1
- AFABGHUZZDYHJO-UHFFFAOYSA-N dimethyl butane Natural products CCCC(C)C AFABGHUZZDYHJO-UHFFFAOYSA-N 0.000 description 1
- HNPSIPDUKPIQMN-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Al]O[Al]=O HNPSIPDUKPIQMN-UHFFFAOYSA-N 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 239000002612 dispersion medium Substances 0.000 description 1
- 239000000975 dye Substances 0.000 description 1
- 238000000635 electron micrograph Methods 0.000 description 1
- 239000000839 emulsion Substances 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 150000002148 esters Chemical class 0.000 description 1
- 150000002170 ethers Chemical class 0.000 description 1
- 229920005680 ethylene-methyl methacrylate copolymer Polymers 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 239000000945 filler Substances 0.000 description 1
- 239000003063 flame retardant Substances 0.000 description 1
- 238000009499 grossing Methods 0.000 description 1
- 239000012760 heat stabilizer Substances 0.000 description 1
- HSEMFIZWXHQJAE-UHFFFAOYSA-N hexadecanamide Chemical compound CCCCCCCCCCCCCCCC(N)=O HSEMFIZWXHQJAE-UHFFFAOYSA-N 0.000 description 1
- BDAGIHXWWSANSR-NJFSPNSNSA-N hydroxyformaldehyde Chemical compound O[14CH]=O BDAGIHXWWSANSR-NJFSPNSNSA-N 0.000 description 1
- 239000002917 insecticide Substances 0.000 description 1
- 150000002576 ketones Chemical class 0.000 description 1
- 229920000092 linear low density polyethylene Polymers 0.000 description 1
- 239000004707 linear low-density polyethylene Substances 0.000 description 1
- 231100000053 low toxicity Toxicity 0.000 description 1
- ZLNQQNXFFQJAID-UHFFFAOYSA-L magnesium carbonate Chemical compound [Mg+2].[O-]C([O-])=O ZLNQQNXFFQJAID-UHFFFAOYSA-L 0.000 description 1
- 239000001095 magnesium carbonate Substances 0.000 description 1
- 229910000021 magnesium carbonate Inorganic materials 0.000 description 1
- 235000014380 magnesium carbonate Nutrition 0.000 description 1
- VTHJTEIRLNZDEV-UHFFFAOYSA-L magnesium dihydroxide Chemical compound [OH-].[OH-].[Mg+2] VTHJTEIRLNZDEV-UHFFFAOYSA-L 0.000 description 1
- 239000000347 magnesium hydroxide Substances 0.000 description 1
- 229910001862 magnesium hydroxide Inorganic materials 0.000 description 1
- 229910001004 magnetic alloy Inorganic materials 0.000 description 1
- 238000007885 magnetic separation Methods 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- AMWRITDGCCNYAT-UHFFFAOYSA-L manganese oxide Inorganic materials [Mn].O[Mn]=O.O[Mn]=O AMWRITDGCCNYAT-UHFFFAOYSA-L 0.000 description 1
- KVGMATYUUPJFQL-UHFFFAOYSA-N manganese(2+) oxygen(2-) Chemical compound [O--].[O--].[O--].[O--].[Mn++].[Mn++].[Mn++] KVGMATYUUPJFQL-UHFFFAOYSA-N 0.000 description 1
- WPBNNNQJVZRUHP-UHFFFAOYSA-L manganese(2+);methyl n-[[2-(methoxycarbonylcarbamothioylamino)phenyl]carbamothioyl]carbamate;n-[2-(sulfidocarbothioylamino)ethyl]carbamodithioate Chemical compound [Mn+2].[S-]C(=S)NCCNC([S-])=S.COC(=O)NC(=S)NC1=CC=CC=C1NC(=S)NC(=O)OC WPBNNNQJVZRUHP-UHFFFAOYSA-L 0.000 description 1
- 239000000155 melt Substances 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 150000002736 metal compounds Chemical class 0.000 description 1
- 229910000000 metal hydroxide Inorganic materials 0.000 description 1
- 150000004692 metal hydroxides Chemical class 0.000 description 1
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 1
- 239000006082 mold release agent Substances 0.000 description 1
- WQEPLUUGTLDZJY-UHFFFAOYSA-N n-Pentadecanoic acid Natural products CCCCCCCCCCCCCCC(O)=O WQEPLUUGTLDZJY-UHFFFAOYSA-N 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- LYRFLYHAGKPMFH-UHFFFAOYSA-N octadecanamide Chemical compound CCCCCCCCCCCCCCCCCC(N)=O LYRFLYHAGKPMFH-UHFFFAOYSA-N 0.000 description 1
- QIQXTHQIDYTFRH-UHFFFAOYSA-N octadecanoic acid Chemical compound CCCCCCCCCCCCCCCCCC(O)=O QIQXTHQIDYTFRH-UHFFFAOYSA-N 0.000 description 1
- OQCDKBAXFALNLD-UHFFFAOYSA-N octadecanoic acid Natural products CCCCCCCC(C)CCCCCCCCC(O)=O OQCDKBAXFALNLD-UHFFFAOYSA-N 0.000 description 1
- 150000007524 organic acids Chemical class 0.000 description 1
- 235000005985 organic acids Nutrition 0.000 description 1
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 description 1
- 229910000889 permalloy Inorganic materials 0.000 description 1
- 239000000049 pigment Substances 0.000 description 1
- 239000002984 plastic foam Substances 0.000 description 1
- 239000004014 plasticizer Substances 0.000 description 1
- 229920006122 polyamide resin Polymers 0.000 description 1
- 229920005668 polycarbonate resin Polymers 0.000 description 1
- 239000004431 polycarbonate resin Substances 0.000 description 1
- 229920001225 polyester resin Polymers 0.000 description 1
- 239000004645 polyester resin Substances 0.000 description 1
- 229920006324 polyoxymethylene Polymers 0.000 description 1
- 229920001155 polypropylene Polymers 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 239000011164 primary particle Substances 0.000 description 1
- 230000000717 retained effect Effects 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 238000000790 scattering method Methods 0.000 description 1
- 229910000702 sendust Inorganic materials 0.000 description 1
- 150000003377 silicon compounds Chemical class 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 239000001509 sodium citrate Substances 0.000 description 1
- NLJMYIDDQXHKNR-UHFFFAOYSA-K sodium citrate Chemical compound O.O.[Na+].[Na+].[Na+].[O-]C(=O)CC(O)(CC([O-])=O)C([O-])=O NLJMYIDDQXHKNR-UHFFFAOYSA-K 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 239000003381 stabilizer Substances 0.000 description 1
- 239000008117 stearic acid Substances 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 229910052712 strontium Inorganic materials 0.000 description 1
- 229910000018 strontium carbonate Inorganic materials 0.000 description 1
- 150000005846 sugar alcohols Polymers 0.000 description 1
- 238000010408 sweeping Methods 0.000 description 1
- 229920003051 synthetic elastomer Polymers 0.000 description 1
- 229920003002 synthetic resin Polymers 0.000 description 1
- 239000000057 synthetic resin Substances 0.000 description 1
- 239000005061 synthetic rubber Substances 0.000 description 1
- 239000010936 titanium Substances 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 description 1
- 238000007666 vacuum forming Methods 0.000 description 1
- 239000004034 viscosity adjusting agent Substances 0.000 description 1
- 239000011800 void material Substances 0.000 description 1
- 238000005303 weighing Methods 0.000 description 1
- 239000010457 zeolite Substances 0.000 description 1
- 229910052725 zinc Inorganic materials 0.000 description 1
- 239000011787 zinc oxide Substances 0.000 description 1
- XOOUIPVCVHRTMJ-UHFFFAOYSA-L zinc stearate Chemical compound [Zn+2].CCCCCCCCCCCCCCCCCC([O-])=O.CCCCCCCCCCCCCCCCCC([O-])=O XOOUIPVCVHRTMJ-UHFFFAOYSA-L 0.000 description 1
Landscapes
- Shielding Devices Or Components To Electric Or Magnetic Fields (AREA)
- Manufacture Of Porous Articles, And Recovery And Treatment Of Waste Products (AREA)
Abstract
Description
本発明は、磁石や電磁波シールド材などに利用できる磁性発泡体及びその製造方法に関する。 The present invention relates to a magnetic foam that can be used for a magnet, an electromagnetic shielding material, and the like, and a method for manufacturing the same.
軽量でクッション性を有する発泡体に磁性粉を含有させることにより、磁性が付与された磁性発泡体を製造する方法が提案されている。特開平５−８２６６号公報（特許文献１）には、射出成形機のノズル口を閉鎖した状態でスクリューを回転させ、樹脂の可塑化を行いながら計量工程を行い、計量工程の終了と同時にスクリューの回転及び後退を停止させ、次にノズル口を開放して所定量の溶融樹脂を金型キャビテイ内に射出し、冷却して成形品を取り出す射出成形方法において、樹脂に体積比で０．２〜２％の発泡剤及び体積比で１０〜３０％の磁性粉を加えたものを用い、計量工程中の溶融樹脂に６５〜４００ｋｇ／ｃｍ２の圧力を与える発泡樹脂磁石の成形方法が開示されている。この文献には、発泡倍率を適当な値（４倍以上）にすることにより、比重１以下の発泡樹脂を成形できると記載されている。 There has been proposed a method for producing a magnetic foam with magnetism by incorporating a magnetic powder into a lightweight and cushioning foam. In JP-A-5-8266 (Patent Document 1), the screw is rotated with the nozzle port of the injection molding machine closed, and the metering process is performed while plasticizing the resin. In the injection molding method in which the rotation and retraction of the resin is stopped, the nozzle port is opened, a predetermined amount of molten resin is injected into the mold cavity, and the molded product is taken out by cooling, the volume ratio of the resin is 0.2. used plus 10-30% of the magnetic powder at 2% of the blowing agent and the volume ratio, the molding method of the foamed resin magnet is disclosed which gives a pressure to the molten resin 65~400kg / cm 2 during the weighing process ing. This document describes that a foamed resin having a specific gravity of 1 or less can be molded by setting the expansion ratio to an appropriate value (4 times or more).
また、特開２００１−２７７２８１号公報（特許文献２）には、所定量の磁性粉が含有された熱可塑性樹脂からなる射出材料を可塑化・射出装置により可塑化すると共に、前記可塑化・射出装置に二酸化炭素、窒素等の物理的発泡剤を注入し、可塑化された溶融樹脂中に超臨界状態の物理的発泡剤を溶解させて発泡溶融樹脂を得て、これを金型のキャビテイに射出して発泡させて比重の小さい発泡樹脂磁石を成形する発泡樹脂磁石の成形方法が開示されている。この文献では、平均セル径０．０１〜５０μｍ、平均セル密度１０８〜１０１６個／ｃｍ３の微細なセル構造を有する発泡体が得られている。 Japanese Patent Laid-Open No. 2001-277281 (Patent Document 2) discloses that an injection material made of a thermoplastic resin containing a predetermined amount of magnetic powder is plasticized by a plasticizing / injecting device, and the plasticizing / injecting is performed. A physical foaming agent such as carbon dioxide or nitrogen is injected into the apparatus, and the physical foaming agent in a supercritical state is dissolved in the plasticized molten resin to obtain a foamed molten resin, which is used as a mold cavity. A method for forming a foamed resin magnet is disclosed in which a foamed resin magnet having a small specific gravity is formed by injection and foaming. In this document, a foam having a fine cell structure with an average cell diameter of 0.01 to 50 μm and an average cell density of 10 8 to 10 16 cells / cm 3 is obtained.
しかし、特許文献１及び２の成形方法では、高発泡倍率の磁性発泡体は得られない。さらに、これらの文献には、溶融樹脂の詳細は記載されていない。 However, in the molding methods of Patent Documents 1 and 2, a magnetic foam having a high expansion ratio cannot be obtained. Further, these documents do not describe details of the molten resin.
特開平７−９４３１３号公報（特許文献３）には、粉末状磁性材料と有機高分子からなる水性粘結剤と熱分解性有機発泡剤とを混合したゾル状原材料を、成形ダイを介して圧送し、薄膜状に送り出し、この薄膜状原材料を常時回動する無継目のコンベアで受け、加熱炉へ搬送し、発泡と同時に溶媒を除去乾燥してシート状とし、前記コンベアから剥離した後に着磁した発泡性磁石の製造方法が開示されている。この文献には、前記有機高分子からなる水性粘結剤として、エチレン−酢酸ビニル共重合体又はアクリル共重合エマルジョンが記載されている。さらに、合成樹脂又は合成ゴムの発泡体内に８０〜９５％の磁性体が分散含有した磁石が得られると記載され、実施例では、約３倍以下の発泡倍率を有する発泡磁石が製造されている。 In JP-A-7-94313 (Patent Document 3), a sol raw material in which a powdery magnetic material, an aqueous binder composed of an organic polymer, and a thermally decomposable organic foaming agent are mixed is formed through a molding die. It is pumped, sent out in a thin film form, this thin film raw material is received by a continuously rotating seamless conveyor, conveyed to a heating furnace, and simultaneously with foaming, the solvent is removed and dried to form a sheet, which is then peeled off from the conveyor. A method for producing a magnetized foamable magnet is disclosed. This document describes an ethylene-vinyl acetate copolymer or an acrylic copolymer emulsion as an aqueous binder made of the organic polymer. Furthermore, it is described that a magnet in which 80 to 95% of a magnetic material is dispersed and contained in a foamed body of synthetic resin or synthetic rubber is obtained. In the examples, a foamed magnet having a foaming ratio of about 3 times or less is manufactured. .
しかし、この製造方法でも、高発泡倍率の磁性発泡体は得られない。 However, even with this production method, a magnetic foam having a high expansion ratio cannot be obtained.
特開２０００−３３６１９９号公報（特許文献４）には、電磁波シールド部材に利用できる発泡体として、ポリオレフィン系樹脂１００重量部、発泡剤１〜５０重量部及び薄片状、粒状又は針状の金属粉１００〜１０００重量部を主成分として含有する樹脂組成物を発泡成形してなるプラスチック発泡体であって、その厚さが２〜８ｍｍであり、かつ最上層の表面に金属が露出しているプラスチック発泡体が開示されている。この文献の実施例では、低密度ポリエチレン（ＬＤＰＥ）１００重量部、発泡剤（アゾジカルボンアミド）１５重量部、鉄粉（針状）２８０重量部、ニッケル粉（針状）１２０重量部を混合して、押出成形した後、オーブン内で発泡させて発泡倍率１５倍の発泡体を製造している。 In JP 2000-336199 A (Patent Document 4), as a foam that can be used for an electromagnetic wave shielding member, 100 parts by weight of a polyolefin resin, 1 to 50 parts by weight of a foaming agent, and a flaky, granular, or acicular metal powder. A plastic foam formed by foam molding a resin composition containing 100 to 1000 parts by weight as a main component, the thickness of which is 2 to 8 mm, and the metal is exposed on the surface of the uppermost layer A foam is disclosed. In an example of this document, 100 parts by weight of low density polyethylene (LDPE), 15 parts by weight of a foaming agent (azodicarbonamide), 280 parts by weight of iron powder (needle shape), and 120 parts by weight of nickel powder (needle shape) are mixed. After the extrusion molding, foaming is performed in an oven to produce a foam having a foaming ratio of 15 times.
しかし、この発泡体では、金属粉が均一に分散するためか、磁性の強さは十分でなく、発泡倍率を向上させるのも困難である。また、金属粉が酸化するため、長期間使用すると、磁力が低下し、耐久性が十分でない。さらに、金属粉が表面から露出しているため、搬送時の擦れなどによって、発泡体が損傷したり、発泡体から金属粉が脱離し易く、取り扱い性が低い。 However, in this foam, the strength of magnetism is not sufficient because the metal powder is uniformly dispersed, and it is difficult to improve the expansion ratio. Moreover, since metal powder oxidizes, when it is used for a long time, magnetic force will fall and durability will not be enough. Furthermore, since the metal powder is exposed from the surface, the foam is easily damaged due to rubbing during transportation or the like, and the metal powder is easily detached from the foam, resulting in poor handling.
従って、本発明の目的は、強い磁性と高い発泡性とを両立できる磁性発泡体及びその製造方法を提供することにある。 Accordingly, an object of the present invention is to provide a magnetic foam capable of achieving both strong magnetism and high foamability and a method for producing the same.
本発明の他の目的は、磁性粒子の脱落を抑制でき、取り扱い性に優れる磁性発泡体及びその製造方法を提供することにある。 Another object of the present invention is to provide a magnetic foam that can suppress the falling off of magnetic particles and is excellent in handleability, and a method for producing the same.
本発明者らは、前記課題を達成するため鋭意検討した結果、熱可塑性樹脂と真比重６ｇ／ｃｍ３以下の磁性粒子とを組み合わせて発泡することにより、強い磁性と高い発泡性とを両立できることを見出し、本発明を完成した。 As a result of intensive studies to achieve the above-mentioned problems, the present inventors can achieve both strong magnetism and high foamability by combining and foaming a thermoplastic resin and magnetic particles having a true specific gravity of 6 g / cm 3 or less. The present invention has been completed.
すなわち、本発明の磁性発泡体は、熱可塑性樹脂と真比重６ｇ／ｃｍ３以下の磁性粒子とを含み、かつ発泡倍率が３倍以上である。前記磁性粒子の平均粒径は０．１〜３００μｍ程度である。前記磁性粒子は複合金属酸化物粒子（特にフェライト粒子）であってもよい。前記熱可塑性樹脂は、オレフィン系樹脂、スチレン系樹脂及び熱可塑性エラストマーからなる群より選択された少なくとも１種であってもよい。前記熱可塑性樹脂と前記磁性粒子との重量割合は、熱可塑性樹脂／磁性粒子＝９７／３〜２０／８０程度である。本発明の磁性発泡体は、発泡倍率が２０倍以上であってもよい。本発明の磁性発泡体は、連続気泡率が０．１〜９０体積％であってもよい。本発明の磁性発泡体は、全表面の８０％以上の面積がスキン層で被覆されていてもよい。本発明の磁性発泡体は、真密度が１〜３ｇ／ｃｍ３程度であってもよい。 That is, the magnetic foam of the present invention contains a thermoplastic resin and magnetic particles having a true specific gravity of 6 g / cm 3 or less and has an expansion ratio of 3 times or more. The average particle size of the magnetic particles is about 0.1 to 300 μm. The magnetic particles may be composite metal oxide particles (particularly ferrite particles). The thermoplastic resin may be at least one selected from the group consisting of an olefin resin, a styrene resin, and a thermoplastic elastomer. The weight ratio of the thermoplastic resin to the magnetic particles is about thermoplastic resin / magnetic particles = 97/3 to 20/80. The magnetic foam of the present invention may have an expansion ratio of 20 times or more. The magnetic foam of the present invention may have an open cell ratio of 0.1 to 90% by volume. In the magnetic foam of the present invention, an area of 80% or more of the entire surface may be covered with a skin layer. The magnetic foam of the present invention may have a true density of about 1 to 3 g / cm 3 .
本発明には、熱可塑性樹脂及び真比重６ｇ／ｃｍ３以下の磁性粒子を含む発泡性樹脂組成物を発泡成形する前記磁性発泡体の製造方法も含まれる。 The present invention also includes a method for producing the magnetic foam, in which a foamable resin composition containing a thermoplastic resin and magnetic particles having a true specific gravity of 6 g / cm 3 or less is foam-molded.
本発明では、熱可塑性樹脂と真比重６ｇ／ｃｍ３以下の低比重磁性粒子とを組み合わせて発泡しているため、強い磁性と高い発泡性とを両立できる。特に、特定の粒径を有する前記磁性粒子を用いることにより、発泡体内部で磁性粒子を適度に局在化できるためか、電磁波シールドや磁石に有用な磁力を向上できる。また、略全表面にスキン層を有するため、磁性粒子の脱落を抑制でき、取り扱い性も向上できる。 In the present invention, since the thermoplastic resin and the low specific gravity magnetic particles having a true specific gravity of 6 g / cm 3 or less are foamed in combination, strong magnetism and high foamability can be achieved. In particular, by using the magnetic particles having a specific particle size, the magnetic particles useful for electromagnetic wave shields and magnets can be improved because the magnetic particles can be appropriately localized inside the foam. In addition, since the skin layer is provided on almost the entire surface, the magnetic particles can be prevented from falling off and the handleability can be improved.
本発明の磁性発泡体は、熱可塑性樹脂と真比重６ｇ／ｃｍ３以下の磁性粒子（低比重磁性粒子）とを含む。 The magnetic foam of the present invention contains a thermoplastic resin and magnetic particles (low specific gravity magnetic particles) having a true specific gravity of 6 g / cm 3 or less.
（熱可塑性樹脂）
熱可塑性樹脂としては、例えば、オレフィン系樹脂、スチレン系樹脂、塩化ビニル系樹脂、酢酸ビニル系樹脂、ポリビニルアルコール系樹脂、アクリル系樹脂、ポリアセタール系樹脂、ポリエステル系樹脂、ポリカーボネート樹脂、ポリアミド系樹脂、これらの樹脂の構成成分を含む熱可塑性エラストマーなどが挙げられる。これらの熱可塑性樹脂は単独又は二種以上組み合わせてもよい。
(Thermoplastic resin)
Examples of the thermoplastic resin include olefin resin, styrene resin, vinyl chloride resin, vinyl acetate resin, polyvinyl alcohol resin, acrylic resin, polyacetal resin, polyester resin, polycarbonate resin, polyamide resin, The thermoplastic elastomer containing the structural component of these resin is mentioned. These thermoplastic resins may be used alone or in combination of two or more.
これらのうち、オレフィン系樹脂、スチレン系樹脂、熱可塑性エラストマー（例えば、オレフィン系熱可塑性エラストマー、スチレン系熱可塑性エラストマーなど）が好ましく、柔軟性や弾性などの機械的特性にも優れる点から、少なくともオレフィン系樹脂を含むのが特に好ましい。 Of these, olefin-based resins, styrene-based resins, and thermoplastic elastomers (for example, olefin-based thermoplastic elastomers, styrene-based thermoplastic elastomers, etc.) are preferable, and at least from the viewpoint of excellent mechanical properties such as flexibility and elasticity, at least It is particularly preferable to include an olefin resin.
オレフィン系樹脂は、通常、ポリエチレン系樹脂、ポリプロピレン系樹脂などのポリＣ２−３オレフィン系樹脂であり、ポリエチレン系樹脂が好ましい。 The olefin resin is usually a poly C2-3 olefin resin such as a polyethylene resin or a polypropylene resin, and a polyethylene resin is preferable.
ポリエチレン系樹脂としては、例えば、低密度ポリエチレン（ＬＤＰＥ）、直鎖状低密度ポリエチレン（ＬＬＤＰＥ）、中密度ポリエチレン（ＭＤＰＥ）、高密度ポリエチレン（ＨＤＰＥ）、エチレン−プロピレン共重合体、エチレン−ブテン−１共重合体、エチレン−プロピレン−ブテン−１共重合体、エチレン−（４−メチルペンテン−１）共重合体、エチレン−酢酸ビニル共重合体（ＥＶＡ樹脂）、エチレン−メチルメタクリレート共重合体などが挙げられる。これらのポリエチレン系樹脂は、単独で又は二種以上組み合わせて使用できる。これらのポリエチレン系樹脂のうち、発泡性などの点から、ＬＤＰＥ、ＬＬＤＰＥ、ＥＶＡ樹脂などが好ましい。 Examples of the polyethylene resin include low density polyethylene (LDPE), linear low density polyethylene (LLDPE), medium density polyethylene (MDPE), high density polyethylene (HDPE), ethylene-propylene copolymer, ethylene-butene- 1 copolymer, ethylene-propylene-butene-1 copolymer, ethylene- (4-methylpentene-1) copolymer, ethylene-vinyl acetate copolymer (EVA resin), ethylene-methyl methacrylate copolymer, etc. Is mentioned. These polyethylene resins can be used alone or in combination of two or more. Of these polyethylene resins, LDPE, LLDPE, EVA resin, and the like are preferable from the viewpoint of foamability.
ポリエチレン系樹脂の数平均分子量は、例えば１０，０００〜３００，０００、好ましくは１５，０００〜２００，０００、さらに好ましくは２０，０００〜１００，０００程度であってもよい。なお、分子量は、ゲルパーミエーションクロマトグラフィー法（ＧＰＣ法）において、測定温度１４０℃で、溶媒としてオルトジクロロベンゼン、及びカラム（Ｓｈｏｄｅｘ ＧＰＣ ＡＤ−８０６ＭＳ）を用いて、ポリスチレンを基準とするユニバーサルキャリブレーションにより測定できる。 The number average molecular weight of the polyethylene resin may be, for example, about 10,000 to 300,000, preferably about 15,000 to 200,000, and more preferably about 20,000 to 100,000. The molecular weight is a universal calibration based on polystyrene, using a gel permeation chromatography method (GPC method) at a measurement temperature of 140 ° C., using orthodichlorobenzene as a solvent and a column (Shodex GPC AD-806MS). Can be measured.
ポリエチレン系樹脂のメルトフローレート（ＭＦＲ）は、ＪＩＳ Ｋ７２１０に準じた方法（１９０℃、荷重２１．２Ｎ）で、０．１ｇ／１０分以上であってもよく、例えば０．１〜２０ｇ／１０分、好ましくは０．３〜１０ｇ／１０分、さらに好ましくは０．５〜５ｇ／１０分（特に０．６〜３ｇ／１０分）程度である。ＭＦＲが小さすぎると、発泡性や強度などが低下する虞がある。 The melt flow rate (MFR) of the polyethylene resin may be 0.1 g / 10 min or more by a method (190 ° C., load 21.2 N) according to JIS K7210, for example, 0.1-20 g / 10. Minutes, preferably 0.3 to 10 g / 10 minutes, more preferably about 0.5 to 5 g / 10 minutes (particularly 0.6 to 3 g / 10 minutes). If the MFR is too small, foamability and strength may be reduced.
前記ポリエチレン系樹脂の融点又は軟化点は、例えば８０〜１５０℃、好ましくは９０〜１４０℃、さらに好ましくは１００〜１３０℃程度である。 The melting point or softening point of the polyethylene resin is, for example, about 80 to 150 ° C., preferably 90 to 140 ° C., and more preferably about 100 to 130 ° C.
オレフィン系樹脂を含む熱可塑性樹脂は、オレフィン系樹脂単独であってもよく、オレフィン系樹脂と他の熱可塑性樹脂（例えば、ポリスチレンなどのスチレン系樹脂）との組み合わせであってもよい。 The thermoplastic resin containing the olefin resin may be an olefin resin alone or a combination of an olefin resin and another thermoplastic resin (for example, a styrene resin such as polystyrene).
オレフィン系樹脂と他の熱可塑性樹脂との重量割合は、オレフィン系樹脂／他の熱可塑性樹脂＝１００／０〜１０／９０（例えば１００／０〜５０／５０）程度の範囲から選択でき、両樹脂を組み合わせる場合、オレフィン系樹脂／他の熱可塑性樹脂＝９９／１〜３０／７０、好ましくは９８／２〜５０／５０、さらに好ましくは９５／５〜７０／３０（特に９３／７〜８０／２０）程度である。オレフィン系樹脂の割合が少なすぎると、発泡性が低下する虞がある。 The weight ratio between the olefin resin and the other thermoplastic resin can be selected from the range of about olefin resin / other thermoplastic resin = 100/0 to 10/90 (for example, 100/0 to 50/50). When the resins are combined, olefin resin / other thermoplastic resin = 99/1 to 30/70, preferably 98/2 to 50/50, more preferably 95/5 to 70/30 (especially 93/7 to 80). / 20) grade. If the ratio of the olefin resin is too small, foamability may be reduced.
（低比重磁性粒子）
本発明の磁性発泡体は、真比重６ｇ／ｃｍ３以下の磁性粒子（低比重磁性粒子）を含むため、トレードオフの関係にある強い磁性と高い発泡性とを両立できるが、その理由は、低比重磁性粒子を含むことにより、発泡体中で磁性粒子を適度に局在化でき、磁力を向上できるためであると推定できる。さらに、低比重磁性粒子の粒径を制御することにより、空隙の壁面やスキン層付近に低比重磁性粒子が局在化し、かつ適度に低比重磁性粒子が凝集した海島構造を形成するためか、発泡性を損なわず、低比重の磁性粒子であるにも拘わらず、磁力を効果的に向上できると推定できる。
(Low specific gravity magnetic particles)
Since the magnetic foam of the present invention includes magnetic particles having a true specific gravity of 6 g / cm 3 or less (low specific gravity magnetic particles), it is possible to achieve both strong magnetism and high foamability in a trade-off relationship. By including the low specific gravity magnetic particles, it can be estimated that the magnetic particles can be appropriately localized in the foam and the magnetic force can be improved. Furthermore, by controlling the particle size of the low specific gravity magnetic particles, the low specific gravity magnetic particles are localized near the wall surface of the void and the skin layer, and the sea island structure in which the low specific gravity magnetic particles are appropriately aggregated is formed. It can be estimated that the magnetic force can be effectively improved in spite of the low specific gravity magnetic particles without impairing the foamability.
低比重磁性粒子の真比重は６ｇ／ｃｍ３以下であればよいが、例えば２〜６ｇ／ｃｍ３、好ましくは３〜５．８ｇ／ｃｍ３、さらに好ましくは４〜５．５ｇ／ｃｍ３（特に４．５〜５．３ｇ／ｃｍ３）程度である。真比重が大きすぎると、強い磁性と高い発泡性とを両立するのが困難となる。 The true specific gravity of the low specific gravity magnetic particles may be 6 g / cm 3 or less, for example 2 to 6 g / cm 3 , preferably 3 to 5.8 g / cm 3 , more preferably 4 to 5.5 g / cm 3 ( In particular, it is about 4.5 to 5.3 g / cm 3 ). If the true specific gravity is too large, it is difficult to achieve both strong magnetism and high foamability.
低比重磁性粒子としては、真比重が６ｇ／ｃｍ３以下であれば、慣用の軟磁性粒子及び硬磁性粒子のいずれの磁性粒子であっても使用でき、例えば、フェライト粒子、アモルファス磁性合金粒子などが挙げられる。これらのうち、強い磁性と高い発泡性とを両立できる点から、フェライト粒子が好ましい。 As the low specific gravity magnetic particles, any magnetic particles such as conventional soft magnetic particles and hard magnetic particles can be used as long as the true specific gravity is 6 g / cm 3 or less. For example, ferrite particles, amorphous magnetic alloy particles, etc. Is mentioned. Of these, ferrite particles are preferred from the viewpoint that both strong magnetism and high foamability can be achieved.
なお、本明細書及び特許請求の範囲において、磁性粒子の真比重は、ＪＩＳ Ｒ９３０１−２−１に準拠して、ピクノメータ方式で測定でき、詳細には、後述の実施例に記載の方法で測定できる。 In the present specification and claims, the true specific gravity of the magnetic particles can be measured by a pycnometer method in accordance with JIS R9301-2-1, and specifically, measured by the method described in the examples below. it can.
フェライト粒子は、酸化鉄を主成分とし、銅、ニッケル、マンガン、亜鉛、コバルト、バリウム、マグネシウムなどの金属酸化物を副成分として含有する複合金属酸化物粒子であり、軟磁性粒子であるソフトフェライトで形成された粒子（ソフトフェライト粒子）であってもよく、硬磁性粒子であるハードソフトフェライトで形成された粒子（ハードフェライト粒子）であってもよく、用途に応じて選択できる。 Ferrite particles are composite metal oxide particles containing iron oxide as a main component and metal oxides such as copper, nickel, manganese, zinc, cobalt, barium and magnesium as subcomponents, and are soft ferrite particles that are soft magnetic particles. The particles may be particles (soft ferrite particles) formed by (1) or may be particles (hard ferrite particles) formed by hard soft ferrite, which is a hard magnetic particle, and can be selected depending on the application.
ソフトフェライトとしては、例えば、Ｍｎ系フェライト、Ｍｎ−Ｚｎ系フェライト、Ｍｎ−Ｍｇ系フェライト、Ｍｇ系フェライト、Ｎｉ−Ｚｎ系フェライト、Ｃｕ−Ｚｎ系フェライト、Ｃｕ−Ｍｇ−Ｚｎ系フェライト、Ｎｉ−Ｃｕ−Ｚｎ系フェライト、Ｎｉ−Ｍｎ−Ｚｎ系フェライトなどが挙げられる。 Examples of the soft ferrite include Mn ferrite, Mn—Zn ferrite, Mn—Mg ferrite, Mg ferrite, Ni—Zn ferrite, Cu—Zn ferrite, Cu—Mg—Zn ferrite, Ni—Cu. -Zn-based ferrite, Ni-Mn-Zn-based ferrite and the like.
これらのソフトフェライトのうち、磁気特性（特に磁化）の制御の容易さの点から、Ｍｎ−Ｍｇ系、Ｍｎ−Ｍｇ−Ｓｒ系、Ｍｎ−Ｍｇ−Ｔｉ系、Ｍｎ系フェライトが好ましい。これらのソフトフェライト粒子は、単独で又は二種以上組み合わせて使用できる。 Among these soft ferrites, Mn—Mg, Mn—Mg—Sr, Mn—Mg—Ti, and Mn ferrite are preferable from the viewpoint of easy control of magnetic properties (particularly magnetization). These soft ferrite particles can be used alone or in combination of two or more.
ソフトフェライトにおいて、例えば、Ｍｎ−Ｍｇ−Ｓｒ系フェライトは、フェライト全体に対して、Ｆｅ含有量は４５〜５５重量％（特に４７．５〜５２．５重量％）、Ｍｎ含有量は１５〜２２重量％（特に１６〜２１重量％）、Ｍｇ含有量は０．５〜３．５重量％（特に１〜３重量％）、Ｓｒ含有量は０〜１．５重量％（特に０．５〜１重量％）程度である。 In the soft ferrite, for example, the Mn—Mg—Sr-based ferrite has an Fe content of 45 to 55 wt% (particularly 47.5 to 52.5 wt%) and an Mn content of 15 to 22 with respect to the entire ferrite. % By weight (especially 16 to 21% by weight), Mg content is 0.5 to 3.5% by weight (especially 1 to 3% by weight), and Sr content is 0 to 1.5% by weight (especially 0.5 to 5%). 1% by weight).
ハードフェライトとしては、例えば、Ｓｒ系フェライト、Ｂａ系フェライトなどが挙げられる。これらのハードフェライトのうち、磁気特性（特に保磁力）の制御の容易さの点から、Ｓｒ系フェライトが好ましい。これらのハードフェライト粒子は、単独で又は二種以上組み合わせて使用できる。 Examples of hard ferrites include Sr ferrite and Ba ferrite. Of these hard ferrites, Sr-based ferrites are preferable from the viewpoint of easy control of magnetic properties (particularly coercive force). These hard ferrite particles can be used alone or in combination of two or more.
ハードフェライトにおいて、Ｓｒ系フェライトは、フェライト全体に対して、Ｆｅ含有量は６１〜６４重量％（特に６２〜６３．５重量％）、Ｓｒ含有量は７．５〜９．５重量％（特に８〜９重量％）、Ｍｇ含有量は０〜０．５重量％（特に０．０１〜０．３重量％）程度である。 In the hard ferrite, the Sr-based ferrite has an Fe content of 61 to 64% by weight (especially 62 to 63.5% by weight) and an Sr content of 7.5 to 9.5% by weight (especially with respect to the entire ferrite). 8 to 9% by weight), and the Mg content is about 0 to 0.5% by weight (particularly 0.01 to 0.3% by weight).
低比重磁性粒子（特にフェライト粒子）のＢＥＴ比表面積は、例えば０．０５〜３０ｍ２／ｇ、好ましくは０．１〜２５ｍ２／ｇ、さらに好ましくは０．２〜２５ｍ２／ｇ（特に０．２５〜２５ｍ２／ｇ）程度である。本明細書及び特許請求の範囲において、ＢＥＴ比表面積は、例えば、比表面積測定装置（型式：Ｍａｃｓｏｒｂ ＨＭ ｍｏｄｅｌ−１２０８（マウンテック社製））を用いて測定できる。 The BET specific surface area of the low specific gravity magnetic particles (particularly ferrite particles) is, for example, 0.05 to 30 m 2 / g, preferably 0.1 to 25 m 2 / g, more preferably 0.2 to 25 m 2 / g (particularly 0). .25-25 m 2 / g). In the present specification and claims, the BET specific surface area can be measured using, for example, a specific surface area measuring device (model: Macsorb HM model-1208 (manufactured by Mountec)).
磁性粒子（特にフェライト粒子）の形状は、特に限定されず、例えば、球状（真球状又は略球状）、楕円体（楕円球）状、多角体状（多角錘状、正方体状や直方体状など多角方形状など）、板状（扁平状、鱗片状、薄片状など）、ロッド状又は棒状、繊維状又は針状、樹針状、不定形状などが挙げられる。これらのうち、真球状などの球状、板状、針状、不定形状などが汎用され、樹脂への分散の容易さから、球状、不定形状が好ましい。 The shape of the magnetic particles (particularly ferrite particles) is not particularly limited. For example, a spherical shape (true spherical shape or substantially spherical shape), an ellipsoidal shape (elliptical sphere) shape, a polygonal shape (polygonal pyramid shape, a rectangular parallelepiped shape, a rectangular parallelepiped shape, or the like) Square shape, etc.), plate shape (flat shape, scale shape, flake shape, etc.), rod shape or rod shape, fiber shape or needle shape, tree needle shape, indefinite shape and the like. Among these, spherical shapes such as true spheres, plate shapes, needle shapes, and irregular shapes are widely used, and spherical shapes and irregular shapes are preferable because of easy dispersion in the resin.
フェライト粒子の平均粒径は、例えば０．１〜３００μｍ、好ましくは０．５〜２００μｍ、さらに好ましくは１〜１００μｍ（特に１．５〜５０μｍ）程度である。さらに、平均粒径は、磁性発泡体の用途に応じて選択してもよく、電磁波シールド材として利用する場合、例えば０．０１〜１００μｍ、好ましくは０．０１〜５０μｍ、さらに好ましくは０．０１〜３５μｍ程度である。磁石として利用する場合、フェライト粒子の平均粒径は、例えば０．１〜５０μｍ、好ましくは０．３〜４０μｍ、さらに好ましくは０．５〜３０μｍ程度である。平均粒径が小さすぎると、磁力が低下する虞があり、大きすぎると、発泡性が低下する虞がある。本明細書及び特許請求の範囲において、平均粒径は、体積平均粒径を意味し、例えば、レーザー回折式粒度分布測定装置により測定でき、詳細には、後述の実施例に記載の方法で測定できる。 The average particle diameter of the ferrite particles is, for example, about 0.1 to 300 μm, preferably about 0.5 to 200 μm, and more preferably about 1 to 100 μm (particularly 1.5 to 50 μm). Further, the average particle diameter may be selected according to the use of the magnetic foam, and when used as an electromagnetic shielding material, for example, 0.01 to 100 μm, preferably 0.01 to 50 μm, more preferably 0.01. It is about ~ 35 μm. When used as a magnet, the average particle size of the ferrite particles is, for example, about 0.1 to 50 μm, preferably about 0.3 to 40 μm, and more preferably about 0.5 to 30 μm. If the average particle size is too small, the magnetic force may decrease, and if it is too large, the foamability may decrease. In the present specification and claims, the average particle diameter means a volume average particle diameter, and can be measured by, for example, a laser diffraction particle size distribution measuring apparatus, and in detail, measured by the method described in the examples below. it can.
フェライト粒子は、慣用の方法、例えば、目的の組成に応じて、原料である金属化合物に対して、必要に応じてバインダー及び分散剤などの添加剤を配合した組成物を焼成する方法などにより製造でき、例えば、特開２０１５−１９６６０７号公報、特開２０１６−６０６８２号公報、特開２０１６−１０６２６２号公報、特開２０１６−１３７４４８号公報、特開２０１６−１３８１８９号公報に記載の方法などにより製造してもよい。 Ferrite particles are produced by a conventional method, for example, a method of firing a composition in which additives such as a binder and a dispersing agent are blended with a metal compound as a raw material, if necessary, according to a target composition. For example, it is manufactured by the method described in JP-A-2015-196607, JP-A-2006-60682, JP-A-2006-106262, JP-A-2006-137448, JP-A-2006-138189, etc. May be.
熱可塑性樹脂と低比重磁性粒子との重量割合は、例えば、熱可塑性樹脂／低比重磁性粒子＝９９／１〜１０／９０（例えば９７／３〜２０／８０）、好ましくは９５／５〜３０／７０（例えば９０／１０〜４０／６０）、さらに好ましくは８０／２０〜５０／５０（特に７０／３０〜６０／４０）程度である。低比重磁性粒子の割合が少なすぎると、磁力が低下する虞があり、逆に多すぎると、発泡性が低下する虞がある。 The weight ratio between the thermoplastic resin and the low specific gravity magnetic particles is, for example, thermoplastic resin / low specific gravity magnetic particles = 99/1 to 10/90 (for example, 97/3 to 20/80), preferably 95/5 to 30. / 70 (for example, 90/10 to 40/60), more preferably about 80/20 to 50/50 (particularly 70/30 to 60/40). If the ratio of the low specific gravity magnetic particles is too small, the magnetic force may be reduced, and conversely if too large, the foamability may be reduced.
（高比重磁性粒子）
本発明の磁性発泡体は、真比重が６ｇ／ｃｍ３を超える高比重磁性粒子をさらに含んでいてもよい。高比重磁性粒子の真比重は６ｇ／ｃｍ３を超えていればよく（例えば６ｇ／ｃｍ３を超えて２３ｇ／ｃｍ３以下）、例えば６．１〜１０ｇ／ｃｍ３、好ましくは６．３〜９．５ｇ／ｃｍ３、さらに好ましくは６．５〜９ｇ／ｃｍ３（特に７〜８．５ｇ／ｃｍ３）程度である。
(High specific gravity magnetic particles)
The magnetic foam of the present invention may further contain high specific gravity magnetic particles having a true specific gravity exceeding 6 g / cm 3 . True specific gravity of the high specific gravity magnetic particles need only exceed 6 g / cm 3 (e.g. 23 g / cm 3 or less exceed 6g / cm 3), for example 6.1~10g / cm 3, preferably 6.3 to It is about 9.5 g / cm 3 , more preferably about 6.5 to 9 g / cm 3 (particularly 7 to 8.5 g / cm 3 ).
高比重磁性粒子としては、真比重が６ｇ／ｃｍ３を超えていれば、慣用の軟磁性粒子及び硬磁性粒子のいずれの磁性粒子であっても使用できる。 As the high specific gravity magnetic particles, any of conventional soft magnetic particles and hard magnetic particles can be used as long as the true specific gravity exceeds 6 g / cm 3 .
軟磁性粒子としては、例えば、純鉄粒子、還元鉄粒子、アトマイズ鉄粒子、ケイ素鋼粒子、パーマロイ粒子、センダスト粒子、パーメンジュール粒子などが挙げられる。これらの軟磁性粒子は、単独で又は二種以上組み合わせて使用できる。 Examples of soft magnetic particles include pure iron particles, reduced iron particles, atomized iron particles, silicon steel particles, permalloy particles, sendust particles, and permendurous particles. These soft magnetic particles can be used alone or in combination of two or more.
硬磁性粒子としては、例えば、アルニコ磁石粒子、Ｃｕ−Ｎｉ−Ｆｅ系合金粒子、Ｃｕ−Ｎｉ−Ｃｏ系合金粒子、Ｐｔ合金粒子、Ｍｎ−Ｂｉ系合金粒子、Ｍｎ−Ａｌ系合金粒子、Ｓｍ−Ｃｏ系合金粒子などが挙げられる。これらの硬磁性粒子は、単独で又は二種以上組み合わせて使用できる。 Examples of the hard magnetic particles include alnico magnet particles, Cu—Ni—Fe alloy particles, Cu—Ni—Co alloy particles, Pt alloy particles, Mn—Bi alloy particles, Mn—Al alloy particles, Sm— Examples include Co-based alloy particles. These hard magnetic particles can be used alone or in combination of two or more.
高比重磁性粒子の形状及び平均粒径は、好ましい態様も含めて、低比重磁性粒子の形状及び平均粒径と同一である。 The shape and average particle diameter of the high specific gravity magnetic particles are the same as the shape and average particle diameter of the low specific gravity magnetic particles including preferred embodiments.
高比重磁性粒子の割合は、低比重磁性粒子１００重量部に対して１００重量部以下であってもよく、例えば５０重量部以下（例えば０．１〜５０重量部）、好ましくは３０重量部以下（例えば０．５〜３０重量部）、さらに好ましくは１０重量部以下（例えば１〜１０重量部）程度である。高比重磁性粒子の割合が多すぎると、強い磁性と高い発泡性との両立が困難となる虞がある。 The ratio of the high specific gravity magnetic particles may be 100 parts by weight or less with respect to 100 parts by weight of the low specific gravity magnetic particles, for example, 50 parts by weight or less (for example, 0.1 to 50 parts by weight), preferably 30 parts by weight or less. (For example, 0.5 to 30 parts by weight), more preferably about 10 parts by weight or less (for example, 1 to 10 parts by weight). If the ratio of the high specific gravity magnetic particles is too large, it may be difficult to achieve both strong magnetism and high foamability.
（発泡剤）
本発明の磁性発泡体は、前記熱可塑性樹脂及び磁性粒子を含む発泡性樹脂組成物を発泡して得られ、発泡性樹脂組成物は、発泡剤を含んでいてもよい。
(Foaming agent)
The magnetic foam of the present invention is obtained by foaming a foamable resin composition containing the thermoplastic resin and magnetic particles, and the foamable resin composition may contain a foaming agent.
発泡剤としては、慣用の発泡剤を使用でき、分解性発泡剤（化学発泡剤）であってもよいが、簡便な方法で、発泡倍率を向上できる点から、揮発性発泡剤（物理発泡剤）が好ましい。揮発性発泡剤としては、例えば、無機系発泡剤（窒素、二酸化炭素、酸素、空気、水など）、有機系発泡剤（脂肪族炭化水素、脂環族炭化水素、芳香族炭化水素、塩素化炭化水素、フッ化炭化水素、アルコール類、エーテル類、アルデヒド類、ケトン類など）などが挙げられる。これらのうち、安価で毒性が低い点から、ブタン（ｎ−ブタン、イソブタン）やペンタン（ｎ−ペンタン、イソペンタンなど）などの低級脂肪族炭化水素が汎用される。 As the foaming agent, a conventional foaming agent can be used, and a decomposable foaming agent (chemical foaming agent) may be used. However, a volatile foaming agent (physical foaming agent) can be used to improve the expansion ratio by a simple method. ) Is preferred. Examples of volatile foaming agents include inorganic foaming agents (nitrogen, carbon dioxide, oxygen, air, water, etc.), organic foaming agents (aliphatic hydrocarbons, alicyclic hydrocarbons, aromatic hydrocarbons, chlorination). Hydrocarbons, fluorinated hydrocarbons, alcohols, ethers, aldehydes, ketones, etc.). Of these, lower aliphatic hydrocarbons such as butane (n-butane, isobutane) and pentane (n-pentane, isopentane, etc.) are widely used because they are inexpensive and have low toxicity.
発泡剤の割合は、熱可塑性樹脂１００重量部に対して、例えば、０．０１〜３０重量部、好ましくは０．１〜２５重量部、さらに好ましくは１〜２０重量部（特に５〜１５重量部）程度である。 The ratio of the foaming agent is, for example, 0.01 to 30 parts by weight, preferably 0.1 to 25 parts by weight, more preferably 1 to 20 parts by weight (particularly 5 to 15 parts by weight) with respect to 100 parts by weight of the thermoplastic resin. Part) grade.
（発泡核剤）
本発明の磁性発泡体は、発泡核剤をさらに含んでいてもよい。発泡核剤としては、例えば、ケイ素化合物（タルク、シリカ、ゼオライトなど）、無機酸塩（重炭酸ナトリウム、炭酸カルシウム、炭酸マグネシウム、炭酸水素ナトリウム、炭酸アンモニウムなどの炭酸塩又は炭酸水素塩など）、有機酸又はその塩（クエン酸、クエン酸ナトリウム、ステアリン酸カルシウム、ステアリン酸アルミニウム、ステアリン酸亜鉛など）、金属酸化物（酸化亜鉛、酸化チタン、酸化アルミニウムなど）、金属水酸化物（水酸化アルミニウムなど）などが挙げられる。これらの発泡核剤は単独で又は二種以上組み合わせて使用してもよい。
(Foaming nucleating agent)
The magnetic foam of the present invention may further contain a foam nucleating agent. Examples of the foam nucleating agent include, for example, silicon compounds (talc, silica, zeolite, etc.), inorganic acid salts (carbonates such as sodium bicarbonate, calcium carbonate, magnesium carbonate, sodium bicarbonate, ammonium carbonate, or bicarbonates), Organic acids or their salts (citric acid, sodium citrate, calcium stearate, aluminum stearate, zinc stearate, etc.), metal oxides (zinc oxide, titanium oxide, aluminum oxide, etc.), metal hydroxides (aluminum hydroxide, etc.) ) And the like. These foam nucleating agents may be used alone or in combination of two or more.
発泡核剤の割合は、熱可塑性樹脂１００重量部に対して、例えば０．０１〜１０重量部、好ましくは０．０５〜５重量部、さらに好ましくは０．１〜３重量部（特に０．５〜２重量部）程度である。 The ratio of the foam nucleating agent is, for example, 0.01 to 10 parts by weight, preferably 0.05 to 5 parts by weight, and more preferably 0.1 to 3 parts by weight (particularly 0.1 to 100 parts by weight) with respect to 100 parts by weight of the thermoplastic resin. 5 to 2 parts by weight).
（収縮防止剤）
本発明の磁性発泡体は、収縮防止剤をさらに含んでいてもよい。収縮防止剤としては、例えば、脂肪酸エステル（パルミチン酸モノ乃至トリグリセリド、ステアリン酸モノ乃至トリグリセリドなどのＣ８−２４脂肪酸と多価アルコールとのエステルなど）、脂肪酸アミド（パルミチン酸アミド、ステアリン酸アミドなどのＣ８−２４脂肪酸アミドなど）などが挙げられる。これらの収縮防止剤は、単独で又は二種以上組み合わせて使用できる。
(Shrinkage prevention agent)
The magnetic foam of the present invention may further contain a shrinkage inhibitor. Examples of the shrinkage preventing agent include fatty acid esters (such as esters of C8-24 fatty acids such as palmitic acid mono to triglycerides and stearic acid mono to triglycerides and polyhydric alcohols), fatty acid amides (palmitic acid amide, stearic acid amide, etc.). And C8-24 fatty acid amide). These shrinkage inhibitors can be used alone or in combination of two or more.
収縮防止剤の割合は、熱可塑性樹脂１００重量部に対して、例えば０．０１〜３０重量部、好ましくは０．０５〜２０重量部、さらに好ましくは０．１〜１０重量部（特に１〜５重量部）程度である。 The proportion of the shrinkage inhibitor is, for example, 0.01 to 30 parts by weight, preferably 0.05 to 20 parts by weight, more preferably 0.1 to 10 parts by weight (particularly 1 to 10 parts by weight) with respect to 100 parts by weight of the thermoplastic resin. 5 parts by weight).
（他の添加剤）
本発明の磁性発泡体は、他の添加剤として、慣用の添加剤をさらに含んでいてもよい。慣用の添加剤としては、着色剤（染料や顔料など）、表面平滑剤、気泡調整剤、安定剤（酸化防止剤、熱安定化剤、紫外線吸収剤など）、粘度調節剤、相溶化剤、分散剤、帯電防止剤、ブロッキング防止剤、防曇剤、充填剤（炭酸カルシウム、炭素繊維など）、滑剤、離型剤、潤滑剤、衝撃改良剤、可塑剤、難燃剤、バイオサイド（殺菌剤、静菌剤、抗かび剤、防腐剤、防虫剤など）、消臭剤などが挙げられる。これら慣用の添加剤は、単独で又は二種以上組み合わせて使用できる。
(Other additives)
The magnetic foam of the present invention may further contain a conventional additive as another additive. Conventional additives include colorants (such as dyes and pigments), surface smoothing agents, bubble regulators, stabilizers (such as antioxidants, heat stabilizers, UV absorbers), viscosity modifiers, compatibilizers, Dispersant, antistatic agent, antiblocking agent, antifogging agent, filler (calcium carbonate, carbon fiber, etc.), lubricant, mold release agent, lubricant, impact modifier, plasticizer, flame retardant, biocide (bactericidal agent) , Bacteriostatic agents, antifungal agents, antiseptics, insecticides, etc.), deodorants and the like. These conventional additives can be used alone or in combination of two or more.
（磁性発泡体の特性）
本発明の磁性発泡体の発泡倍率は、３倍以上（例えば３〜７０倍）であればよく、例えば３．１〜６０倍、好ましくは３．５〜５０倍、さらに好ましくは５〜４５倍（特に１０〜４０倍）程度である。本発明では、磁性粒子を含むにも拘わらず、高い発泡倍率も可能であり、例えば１０倍以上（特に２０倍以上）の発泡倍率も可能であり、例えば１０〜７０倍、好ましくは２０〜６０倍、さらに好ましくは３０〜５０倍（特に３５〜４５倍）程度であってもよい。発泡倍率が低すぎると、柔軟性が低下する虞がある。
(Characteristics of magnetic foam)
The expansion ratio of the magnetic foam of the present invention may be 3 times or more (for example, 3 to 70 times), for example, 3.1 to 60 times, preferably 3.5 to 50 times, more preferably 5 to 45 times. (Especially 10 to 40 times). In the present invention, although it contains magnetic particles, a high expansion ratio is also possible, for example, an expansion ratio of 10 times or more (particularly 20 times or more) is also possible, for example, 10 to 70 times, preferably 20 to 60 times. It may be about 30 to 50 times (particularly about 35 to 45 times). If the expansion ratio is too low, flexibility may be reduced.
本発明の磁性発泡体は、少なくとも独立気泡構造を含むのが好ましく、気泡全体（連続気泡と独立気泡との合計）に対する連続気泡の割合である連続気泡率は９０体積％以下であってもよく、例えば０．１〜９０体積％、好ましくは１〜８０体積％（例えば２〜７０体積％）、さらに好ましくは３〜５０体積％（特に５〜４０体積％）程度である。連続気泡率が高すぎると、発泡体の機械的特性が低下する虞がある。本発明では、磁性粒子として、比重が小さく、体積が大きいため、独立発泡が困難な磁性粒子を用いているにも拘わらず、特定の熱可塑性樹脂と特定の磁性粒子との組み合わせにより、このような高い独立気泡率を実現できる。 The magnetic foam of the present invention preferably includes at least a closed cell structure, and the open cell ratio, which is the ratio of open cells to the entire cells (total of open cells and closed cells), may be 90% by volume or less. For example, it is about 0.1 to 90% by volume, preferably about 1 to 80% by volume (for example, 2 to 70% by volume), and more preferably about 3 to 50% by volume (particularly 5 to 40% by volume). If the open cell ratio is too high, the mechanical properties of the foam may be reduced. In the present invention, the magnetic particles have a small specific gravity and a large volume, so that the combination of a specific thermoplastic resin and a specific magnetic particle makes it possible to use such a magnetic particle. A high closed cell rate can be realized.
本発明の磁性発泡体の平均気泡径は、例えば０．３〜２ｍｍ、好ましくは０．４〜１．５ｍｍ、さらに好ましくは０．５〜１．３ｍｍ（特に０．６〜１ｍｍ）程度である。平均気泡径が小さすぎると、発泡倍率を高くするのが困難となる虞があり、大きすぎると、機械的特性が低下する虞がある。 The average cell diameter of the magnetic foam of the present invention is, for example, about 0.3 to 2 mm, preferably 0.4 to 1.5 mm, more preferably about 0.5 to 1.3 mm (particularly 0.6 to 1 mm). . If the average cell diameter is too small, it may be difficult to increase the expansion ratio. If it is too large, the mechanical properties may be deteriorated.
本発明の磁性発泡体は、表面にスキン層を有するのが好ましく、全表面に対するスキン層の被覆率は６０面積％以上（特に８０面積％以上）であってもよく、好ましくは９０面積％以上であってもよく、１００面積％（全表面がスキン層）であってもよい。スキン層は、磁性発泡体の表面において、略均一な厚みで延びる非発泡層を意味する。 The magnetic foam of the present invention preferably has a skin layer on the surface, and the coverage of the skin layer with respect to the entire surface may be 60 area% or more (particularly 80 area% or more), preferably 90 area% or more. It may be 100% by area (the entire surface is a skin layer). The skin layer means a non-foamed layer extending with a substantially uniform thickness on the surface of the magnetic foam.
スキン層の平均厚みは、０．００１〜１ｍｍ程度の範囲から選択でき、例えば０．００５〜０．１ｍｍ、好ましくは０．００８〜０．０５ｍｍ、さらに好ましくは０．０１〜０．０３ｍｍ（特に０．０１２〜０．０２５ｍｍ）程度である。スキン層の平均厚みが薄すぎると、磁性粒子が脱落したり、取り扱い性が低下する虞があり、逆に厚すぎると、発泡性が低下する虞がある。 The average thickness of the skin layer can be selected from the range of about 0.001 to 1 mm, for example, 0.005 to 0.1 mm, preferably 0.008 to 0.05 mm, more preferably 0.01 to 0.03 mm (particularly 0.012 to 0.025 mm). If the average thickness of the skin layer is too thin, the magnetic particles may fall off or the handleability may be reduced. Conversely, if the skin layer is too thick, the foamability may be reduced.
なお、本明細書及び特許請求の範囲において、発泡倍率、連続気泡率、平均気泡径及びスキン層の平均厚みは、後述の実施例に記載の方法で測定できる。 In the present specification and claims, the expansion ratio, the open cell ratio, the average cell diameter, and the average thickness of the skin layer can be measured by the methods described in Examples below.
本発明の磁性発泡体の真密度は、例えば１〜３ｇ／ｃｍ３、好ましくは１．２〜２．８ｇ／ｃｍ３（例えば１．５〜２．６ｇ／ｃｍ３）、さらに好ましくは１．８〜２．５ｇ／ｃｍ３（特に１．９〜２．２ｇ／ｃｍ３）程度である。真密度が小さすぎると、磁力が低下する虞があり、逆に大きすぎると、発泡性が低下する虞がある。 The true density of the magnetic foam of the present invention is, for example, 1 to 3 g / cm 3 , preferably 1.2 to 2.8 g / cm 3 (for example, 1.5 to 2.6 g / cm 3 ), and more preferably 1. It is about 8 to 2.5 g / cm 3 (particularly 1.9 to 2.2 g / cm 3 ). If the true density is too small, the magnetic force may be reduced. Conversely, if the true density is too high, the foamability may be reduced.
なお、本明細書及び特許請求の範囲において、磁性発泡体の真密度は、ＪＩＳ Ｋ７１１２に準じて測定できる。 In the present specification and claims, the true density of the magnetic foam can be measured according to JIS K7112.
本発明の磁性発泡体は、硬磁性粒子（特に、ハードフェライト粒子）を含む場合、保磁力及び残留磁化の値は大きければ大きいほどよい。保磁力が大きい場合は、外部からの印加磁場が大きくなっても磁性体内部の磁気モーメントが消磁されにくく、磁力を保持できるため、安定して磁力線を出す用途（永久磁石として使用する用途）に適している。残留磁化は保持する磁力に相当し、永久磁石として使用する際に永久磁石の強さとなる。 When the magnetic foam of the present invention contains hard magnetic particles (particularly hard ferrite particles), the larger the coercive force and the residual magnetization values, the better. When the coercive force is large, the magnetic moment inside the magnetic material is not easily demagnetized even if the externally applied magnetic field is large, and the magnetic force can be maintained. Is suitable. The residual magnetization corresponds to the magnetic force to be retained, and becomes the strength of the permanent magnet when used as a permanent magnet.
硬磁性粒子（特に、ハードフェライト粒子）を含む磁性発泡体の保磁力は、例えば１０００〜４５００（Ｏｅ）、好ましくは２０００〜４５００（Ｏｅ）程度である。保磁力が小さすぎると、外部磁場により消磁され易くなり、長期間にわたり安定して磁力線を出す用途（永久磁石として使用する用途）に向かない虞がある。なお、後述する実施例で使用するハードフェライト粒子では保磁力が４５００（Ｏｅ）を超えることはない。 The coercive force of the magnetic foam containing hard magnetic particles (particularly hard ferrite particles) is, for example, about 1000 to 4500 (Oe), preferably about 2000 to 4500 (Oe). If the coercive force is too small, the magnetic field is easily demagnetized by an external magnetic field, which may not be suitable for an application that uses a magnetic field line stably for a long period of time (an application used as a permanent magnet). Note that the coercive force of the hard ferrite particles used in the examples described later does not exceed 4500 (Oe).
硬磁性粒子（特に、ハードフェライト粒子）を含む磁性発泡体の残留磁化は、例えば１〜３５（ｅｍｕ／ｇ）、好ましくは５〜３５（ｅｍｕ／ｇ）程度である。残留磁化が小さすぎると、殆ど磁力が発生しないため、磁性発泡体として機能しない虞がある。なお、後述する実施例で使用するハードフェライト粒子では残留磁化が３５（ｅｍｕ／ｇ）を超えることはない。 The residual magnetization of the magnetic foam including hard magnetic particles (particularly hard ferrite particles) is, for example, about 1 to 35 (emu / g), preferably about 5 to 35 (emu / g). If the remanent magnetization is too small, almost no magnetic force is generated, so that there is a possibility that it does not function as a magnetic foam. In the hard ferrite particles used in the examples described later, the residual magnetization does not exceed 35 (emu / g).
本発明の磁性発泡体は、軟磁性粒子（特に、ソフトフェライト粒子）を含む場合、飽和磁化の値は大きければ大きいほどよい。飽和磁化が大きい場合は、外部からの印加磁場（永久磁石）が弱い場合でも磁力でひきつけられやすい。 When the magnetic foam of the present invention contains soft magnetic particles (particularly soft ferrite particles), the larger the saturation magnetization value, the better. When the saturation magnetization is large, even when the externally applied magnetic field (permanent magnet) is weak, it is easily attracted by the magnetic force.
軟磁性粒子（特に、ソフトフェライト粒子）を含む磁性発泡体の飽和磁化は、例えば１０〜１３０（ｅｍｕ／ｇ）、好ましくは２０〜１３０（ｅｍｕ／ｇ）程度である。飽和磁化が小さすぎると、外部からの印加磁場（永久磁石）が強い場合でも磁力によりひきつけられにくくなり、磁力による磁性発泡体の固定が出来なくなる虞がある。なお、真比重６ｇ／ｃｍ３以下のソフトフェライト粒子と真比重６ｇ／ｃｍ３より大きい磁性粒子とを用いても飽和磁化が１３０（ｅｍｕ／ｇ）よりも高くなることはない。 The saturation magnetization of the magnetic foam containing soft magnetic particles (particularly soft ferrite particles) is, for example, about 10 to 130 (emu / g), preferably about 20 to 130 (emu / g). If the saturation magnetization is too small, even when the externally applied magnetic field (permanent magnet) is strong, it is difficult to attract the magnetic foam and there is a possibility that the magnetic foam cannot be fixed by the magnetic force. Note that not be higher than the saturation magnetization be used with a true specific gravity of 6 g / cm 3 or less of the soft ferrite particles and a true specific gravity of 6 g / cm 3 greater than the magnetic particles 130 (emu / g).
本発明の磁性発泡体は、電磁波シールド性を有しており、軟磁性粒子（特に、ソフトフェライト粒子）を含む磁性発泡体では、例えば１〜３０ＧＨｚ、好ましくは１〜２０ＧＨｚ、さらに好ましくは５〜２０ＧＨｚ程度の電磁波のシールド性に優れており、特に５〜１０ＧＨｚの範囲においては、安定した電磁波シールド性を有している。なお、本明細書及び特許請求の範囲において、電磁波シールド性は、ＩＥＣ６２３３３に準拠した伝送減衰率測定方法（マイクロストリップライン）で測定でき、詳細には、後述の実施例に記載の方法で測定できる。 The magnetic foam of the present invention has electromagnetic wave shielding properties. For a magnetic foam containing soft magnetic particles (particularly soft ferrite particles), for example, 1 to 30 GHz, preferably 1 to 20 GHz, and more preferably 5 to 5 GHz. It has excellent shielding properties for electromagnetic waves of about 20 GHz, and has a stable electromagnetic shielding property particularly in the range of 5 to 10 GHz. In addition, in this specification and a claim, electromagnetic wave shielding property can be measured with the transmission attenuation factor measuring method (microstrip line) based on IEC62333, and can be specifically measured with the method as described in the below-mentioned Example. .
［磁性発泡体の製造方法］
本発明の磁性発泡体の製造方法は、熱可塑性樹脂及び低比重磁性粒子を含む発泡性樹脂組成物を発泡成形する方法であればよく、慣用の方法を利用できるが、通常、前記樹脂組成物を溶融混練し、発泡成形する方法である。
[Method for producing magnetic foam]
The method for producing the magnetic foam of the present invention may be a method for foam-molding a foamable resin composition containing a thermoplastic resin and low specific gravity magnetic particles, and a conventional method can be used. Is melt-kneaded and foam-molded.
溶融混練は、慣用の溶融混練機、例えば、一軸又はベント式二軸押出機などを用いて溶融混錬してもよい。また、溶融混練に先だって、慣用の方法、例えば、混合機（タンブラー、Ｖ型ブレンダー、ヘンシェルミキサー、ナウタミキサー、リボンミキサー、メカノケミカル装置、押出混合機など）を用いて、熱可塑性樹脂と、磁性粒子と、他の成分（発泡剤及び必要に応じて発泡核剤、添加剤など）とを予備混合してもよい。 The melt-kneading may be performed by melt-kneading using a conventional melt-kneader, for example, a uniaxial or vented twin-screw extruder. Prior to melt-kneading, a thermoplastic resin and magnetic material can be obtained by using a conventional method such as a mixer (such as a tumbler, V-type blender, Henschel mixer, Nauta mixer, ribbon mixer, mechanochemical apparatus, extrusion mixer). You may premix particle | grains and other components (A foaming agent and a foaming nucleating agent, an additive, etc. as needed).
発泡成形法としては、慣用の方法、例えば、押出成形法（例えば、Ｔダイ法、インフレーション法など）、射出成形法などが使用できる。これらのうち、強い磁力と高い発泡性を有する発泡体を高い生産性で製造できる点から、押出成形法が好ましい。 As the foam molding method, a conventional method such as an extrusion molding method (for example, a T-die method, an inflation method, etc.), an injection molding method, or the like can be used. Among these, the extrusion molding method is preferable because a foam having strong magnetic force and high foamability can be produced with high productivity.
押出成形法において、押出機としては、例えば、単軸押出機（例えば、ベント式押出機など）、二軸押出機（例えば、同方向二軸押出機、異方向二軸押出機など）などが利用でき、発泡条件を調整し易く、高発泡率を実現できる点から、タンデム押出機などの多段押出機が好ましい。 In the extrusion molding method, examples of the extruder include a single-screw extruder (for example, a vent-type extruder), a twin-screw extruder (for example, a same-direction twin-screw extruder, a different-direction twin-screw extruder, etc.), and the like. A multi-stage extruder such as a tandem extruder is preferred because it can be used, the foaming conditions can be easily adjusted, and a high foaming rate can be realized.
押出成形法において、発泡剤を導入する方法は特に限定されず、分解性発泡剤（化学発泡剤）を予め発泡性樹脂組成物に配合してもよいが、簡便な方法で、発泡倍率を向上できる点から、押出機において揮発性発泡剤（物理発泡剤）を導入するのが好ましい。 In the extrusion molding method, the method for introducing the foaming agent is not particularly limited, and a decomposable foaming agent (chemical foaming agent) may be blended with the foamable resin composition in advance, but the foaming ratio is improved by a simple method. From the point of view, it is preferable to introduce a volatile foaming agent (physical foaming agent) in the extruder.
口金の吐出口（ダイのリップ）の形状は、特に制限されず被保護体（又は物品）の形態に応じて選択でき、例えば、棒状、紐状などの一次元的形状、シート状、フィルム状、二次元網目（ネット）状などの二次元的形状、ブロック状、板状、柱状、スリット状、Ｌ字状、コ型状、パイプ状又はリング状などの三次元的形状であってもよい。シート状発泡体は、少なくとも一方の面が平坦面又は凹凸面であってもよく、一方の面が凹凸面に形成され、他方の面が凹凸面であってもよい。この凹凸面は、長尺のシート状発泡体では長手方向に沿って形成する場合が多い。凹凸面を形成することにより、被保護体の滑りを抑制でき、緩衝効果を高めることができる。凹凸部の高さは特に制限されない。 The shape of the discharge port (die lip) of the base is not particularly limited and can be selected according to the form of the object to be protected (or article). It may be a two-dimensional shape such as a two-dimensional mesh shape, a block shape, a plate shape, a column shape, a slit shape, an L shape, a U shape, a pipe shape or a ring shape. . At least one surface of the sheet-like foam may be a flat surface or an uneven surface, one surface may be formed as an uneven surface, and the other surface may be an uneven surface. This uneven surface is often formed along the longitudinal direction of a long sheet-like foam. By forming the concavo-convex surface, it is possible to suppress the slip of the protected body and enhance the buffering effect. The height of the uneven portion is not particularly limited.
押出発泡された発泡体は、慣用の方法、例えば、冷却器を用いた冷却方法で冷却してもよい。冷却器を用いた冷却方法において、冷却媒体としては、圧縮エアー、水（冷却水）、空気（ブロア）などの冷却媒体が挙げられる。冷却方法としては、圧縮エアーを噴射する方法、ブロアで冷却する方法、水を噴霧して冷却する方法、冷却ジャケットを用いて冷却する方法などが挙げられる。冷却媒体の温度は、例えば０〜６０℃、好ましくは５〜５５℃、さらに好ましくは１０〜５０℃程度であってもよい。 The extruded foam may be cooled by a conventional method, for example, a cooling method using a cooler. In the cooling method using a cooler, examples of the cooling medium include cooling media such as compressed air, water (cooling water), and air (blower). Examples of the cooling method include a method of jetting compressed air, a method of cooling with a blower, a method of spraying water to cool, a method of cooling using a cooling jacket, and the like. The temperature of the cooling medium may be, for example, 0 to 60 ° C, preferably 5 to 55 ° C, and more preferably about 10 to 50 ° C.
圧縮エアーを噴射する方法において、エアーの圧力は、例えば０．１〜１０ＭＰａ、好ましくは０．２〜５ＭＰａ、さらに好ましくは０．３〜１ＭＰａ程度であってもよい。圧縮エアーの噴射量は、例えば１００〜１０００リットル／分、好ましくは２００〜５００リットル／分、さらに好ましくは２５０〜４００リットル／分程度であってもよい。 In the method of injecting compressed air, the air pressure may be, for example, about 0.1 to 10 MPa, preferably about 0.2 to 5 MPa, and more preferably about 0.3 to 1 MPa. The amount of compressed air injected may be, for example, about 100 to 1000 liters / minute, preferably about 200 to 500 liters / minute, and more preferably about 250 to 400 liters / minute.
また、必要により、得られた磁性発泡体（特に、シート状発泡体）を二次加工［例えば、真空成形、圧空成形、真空圧空成形、マッチモールド成形などの熱成形（例えば、金型を用いる熱成形）］してもよい。 Further, if necessary, the obtained magnetic foam (particularly, sheet-like foam) is subjected to secondary processing [for example, thermoforming such as vacuum forming, pressure forming, vacuum pressure forming, match mold forming (for example, using a mold). Thermoforming)].
なお、発泡成形又は二次成形温度は、例えば７０〜３００℃、好ましくは８０〜２８０℃、さらに好ましくは８５〜２６０℃程度であってもよい。 The foam molding or secondary molding temperature may be, for example, 70 to 300 ° C, preferably 80 to 280 ° C, and more preferably about 85 to 260 ° C.
発泡体の形状は、用途に応じて任意の形状に適宜選択でき、例えば、棒状、シート状、三次元形状などであってもよい。 The shape of the foam can be appropriately selected depending on the application, and may be, for example, a rod shape, a sheet shape, or a three-dimensional shape.
以下に、実施例に基づいて本発明をより詳細に説明するが、本発明はこれらの実施例によって限定されるものではない。実施例及び比較例で用いた原料、及びフェライト粒子の製造方法は以下の通りであり、得られたフェライト粒子及び磁性発泡体の特性は以下の方法で評価した。 Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples. The raw materials used in Examples and Comparative Examples and the method for producing ferrite particles are as follows, and the properties of the obtained ferrite particles and magnetic foam were evaluated by the following methods.
［原料］
ＬＤＰＥ：低密度ポリエチレン、東ソー（株）製「１７０」
イソブタン（発泡剤）：市販品
発泡核剤：タルク、永和化成（株）製「ＥＥ２７５」
収縮防止剤：ベーリンガーインゲルハイムケミカルズ（株）製「アクティベックス３２５」
還元鉄粉：パウダーテック（株）製「ＲＤ−Ｃ」、体積平均粒径３０μｍ、真比重７．０４ｇ／ｃｍ３。
[material]
LDPE: Low density polyethylene, "170" manufactured by Tosoh Corporation
Isobutane (foaming agent): Commercial product Foaming nucleating agent: Talc, “EE275” manufactured by Eiwa Kasei Co., Ltd.
Antishrink agent: “Activex 325” manufactured by Boehringer Ingelheim Chemicals
Reduced iron powder: “RD-C” manufactured by Powder Tech Co., Ltd., volume average particle size 30 μm, true specific gravity 7.04 g / cm 3 .
［ハードフェライト粒子の製造方法］
フェライト原料として、Ｆｅ２Ｏ３とＳｒＣＯ３とを、Ｆｅ２Ｏ３／ＳｒＣＯ３＝５．７５／１のモル比で用い、これらの原料をヘンシェルミキサーで１０分混合した。得られた混合物を、固定式電気炉を用い、大気中、１１００℃で４時間（ピーク）本焼成し、Ｓｒフェライト粉を得た。
[Method for producing hard ferrite particles]
Fe 2 O 3 and SrCO 3 were used as ferrite raw materials in a molar ratio of Fe 2 O 3 / SrCO 3 = 5.75 / 1, and these raw materials were mixed with a Henschel mixer for 10 minutes. The obtained mixture was subjected to main firing at 1100 ° C. for 4 hours (peak) in the air using a stationary electric furnace to obtain Sr ferrite powder.
さらに、上記本焼成で得られた焼成物を、ビーズミルを用いて固形分６０重量％で３０分湿式粉砕し、洗浄、脱水、乾燥後、大気中、８５０℃で１時間（ピーク）熱処理し、熱処理済Ｓｒフェライト粉を得た。得られたハードフェライト粒子の体積平均粒径は１．７μｍ、真比重は５．１１ｇ／ｃｍ３であった。 Furthermore, the fired product obtained by the main firing was wet pulverized at a solid content of 60% by weight using a bead mill for 30 minutes, washed, dehydrated, dried, and then heat treated at 850 ° C. for 1 hour in air. Heat-treated Sr ferrite powder was obtained. The obtained hard ferrite particles had a volume average particle size of 1.7 μm and a true specific gravity of 5.11 g / cm 3 .
［ソフトフェライト粒子の製造方法］
ＭｎＯとＭｇＯとＦｅ２Ｏ３とＳｒＯとが、ＭｎＯ／ＭｇＯ／Ｆｅ２Ｏ３／ＳｒＯ＝３９／１１／５０／０．５のモル比になるように原料を秤量し、乾式のメディアミルで５時間粉砕し、得られた粉砕物をローラーコンパクターにて、約１ｍｍ角のペレットにした。ＭｎＯ原料としては四酸化三マンガンを、ＭｇＯ原料としては水酸化マグネシウムを、ＳｒＯ原料としては、炭酸ストロンチウムをそれぞれ用いた。
[Method for producing soft ferrite particles]
The raw materials are weighed so that MnO, MgO, Fe 2 O 3 and SrO have a molar ratio of MnO / MgO / Fe 2 O 3 /SrO=39/11/50/0.5. The mixture was pulverized for 5 hours, and the resulting pulverized product was formed into approximately 1 mm square pellets using a roller compactor. Trimanganese tetraoxide was used as the MnO raw material, magnesium hydroxide was used as the MgO raw material, and strontium carbonate was used as the SrO raw material.
このペレットを粗粉と微粉を除去した後、連続式電気炉で、９５０℃で３時間加熱し、仮焼成を行った。次いで、乾式のメディアミルを用いて、平均粒径が約５μｍまで粉砕した後、水を加え、さらに湿式のメディアミルを用いて粉砕した。このスラリーの粒径（粉砕の一次粒子径）をマイクロトラック粒度分析計（日機装（株）製「Ｍｏｄｅｌ９３２０−Ｘ１００」）にて測定した結果、Ｄ５０は約２μｍであった。このスラリーに分散剤を適量添加し、バインダーとしてポリビニルアルコール１０重量％水溶液を固形分に対して０．４重量％添加し、次いでスプレードライヤーにより造粒、乾燥し、得られた粒子（造粒物）の粒度調整を行い、その後、ロータリー式電気炉を用い、大気雰囲気で、７５０℃で２時間加熱し、分散剤やバインダーなどの有機成分の除去を行った。 After the coarse powder and fine powder were removed from the pellets, the pellets were heated at 950 ° C. for 3 hours in a continuous electric furnace to perform temporary firing. Next, after crushing to an average particle size of about 5 μm using a dry media mill, water was added, and further using a wet media mill. As a result of measuring the particle size (pulverized primary particle size) of this slurry with a Microtrac particle size analyzer (“Model 9320-X100” manufactured by Nikkiso Co., Ltd.), D 50 was about 2 μm. An appropriate amount of a dispersant is added to this slurry, and a polyvinyl alcohol 10 wt% aqueous solution is added as a binder in an amount of 0.4 wt% with respect to the solid content, and then granulated and dried by a spray drier. ), And then, using a rotary electric furnace, heated in an air atmosphere at 750 ° C. for 2 hours to remove organic components such as a dispersant and a binder.
その後、トンネル式電気炉にて、焼成温度１１５０℃、酸素濃度０．０１容量％にて、５時間保持した。この時、昇温速度を１５０℃／時、冷却速度を１１０℃／時とした。その後、解砕し、さらに分級して粒度調整を行い、磁力選鉱により低磁力品を分別し、ソフトフェライト粒子を得た。得られたソフトフェライト粒子の体積平均粒径は１４．７μｍ、真比重は４．８９ｇ／ｃｍ３であった。 Then, it was held for 5 hours at a firing temperature of 1150 ° C. and an oxygen concentration of 0.01 vol% in a tunnel electric furnace. At this time, the heating rate was 150 ° C./hour and the cooling rate was 110 ° C./hour. After that, it was crushed, further classified to adjust the particle size, and the low-magnetism product was fractionated by magnetic separation to obtain soft ferrite particles. The obtained soft ferrite particles had a volume average particle diameter of 14.7 μm and a true specific gravity of 4.89 g / cm 3 .
［フェライト粒子の体積平均粒径］
フェライト粒子の体積平均粒径は、マイクロトラック粒度分析計（日機装（株）製「Ｍｏｄｅｌ９３２０−Ｘ１００」）を用いてレーザー回折散乱法により測定した。屈折率は２．４２とし、２５±５℃、湿度５５±１５％の環境下で測定を行った。体積平均粒径（メジアン径）は、体積分布モード、ふるい下表示での累積５０％粒子径である。なお、分散媒としては水を用いた。
[Volume average particle diameter of ferrite particles]
The volume average particle diameter of the ferrite particles was measured by a laser diffraction scattering method using a Microtrac particle size analyzer (“Model 9320-X100” manufactured by Nikkiso Co., Ltd.). The refractive index was 2.42, and the measurement was performed in an environment of 25 ± 5 ° C. and humidity 55 ± 15%. The volume average particle diameter (median diameter) is a cumulative 50% particle diameter in a volume distribution mode and under a sieve display. Note that water was used as the dispersion medium.
［フェライト粒子の真比重］
フェライト粒子の真比重は、ＪＩＳ Ｒ９３０１−２−１に準拠して、ウルトラ・ピクノメーター（ユアサアイオニクス（株）製）を用いて、ピクノメータ方式で測定した。
[True specific gravity of ferrite particles]
The true specific gravity of the ferrite particles was measured by a pycnometer method using an ultra pycnometer (manufactured by Yuasa Ionics Co., Ltd.) according to JIS R9301-2-1.
［磁性発泡体の真密度］
実施例及び比較例で得られた発泡体の真密度（ｇ／ｃｍ３）は、ＪＩＳ Ｋ７１１２に準じて測定した。
[True density of magnetic foam]
The true density (g / cm 3 ) of the foams obtained in Examples and Comparative Examples was measured according to JIS K7112.
［発泡倍率］
発泡倍率は、以下の式に基づいて算出した。
[Foaming ratio]
The expansion ratio was calculated based on the following formula.
発泡倍率（倍）＝発泡体用樹脂組成物の密度／発泡体の見掛密度。 Expansion ratio (times) = density of resin composition for foam / apparent density of foam.
［連続気泡率］
実施例及び比較例で得られた発泡体を、予め重量を測定し、水中に静置した後、−４００ｍｍＨｇの減圧下に１分間放置して、連続気泡構造の中に水を浸透させた。減圧状態から大気圧力に戻し、発泡体の表面に付着した水を除去して重量を測定した後、下記式（１）により算出した。
[Open cell ratio]
The foams obtained in Examples and Comparative Examples were weighed in advance and allowed to stand in water, and then left under a reduced pressure of −400 mmHg for 1 minute to allow water to penetrate into the open cell structure. The pressure was returned to atmospheric pressure from the reduced pressure state, the water adhering to the surface of the foam was removed and the weight was measured.
連続気泡率（％）＝｛（ｗ２−ｗ１）／ｄ３｝／（ｗ１／ｄ１−ｗ１／ｄ２） （１）
（式中、ｗ２は吸水後の発泡体重量、ｗ１は吸水前の発泡体重量、ｄ１は発泡体の見掛密度、ｄ２は発泡体に使用されている樹脂組成物の見掛密度、ｄ３は測定時の水の密度を示す）。
Open cell ratio (%) = {(w 2 −w 1 ) / d 3 } / (w 1 / d 1 −w 1 / d 2 ) (1)
(Wherein, w 2 are weight of foam after water absorption, weight of foam before w 1 is water, the apparent of d 1 is the apparent density of the foam, d 2 is the resin composition used in the foam Density, d 3 indicates the density of water at the time of measurement).
［気泡径（セルサイズ）］
発泡体の断面を走査型電子顕微鏡又はデジタル顕微鏡（スカラ（株）製）で観察し、ＴＤ方向及びＭＤ方向の気泡径を任意の１０箇所で測定し、平均値を気泡径とした。また、各々の気泡径は、長径と短径との平均値とした。
[Bubble diameter (cell size)]
The cross section of the foam was observed with a scanning electron microscope or a digital microscope (manufactured by SCARA Co., Ltd.), the bubble diameters in the TD direction and the MD direction were measured at any 10 locations, and the average value was taken as the bubble diameter. Moreover, each bubble diameter was made into the average value of a major axis and a minor axis.
［スキン層の平均厚み］
電子顕微鏡（スカラ（株）製）及びファイリング＆２次元計測ソフトウェア（（株）アートレイ製「ＡＲ−ＣＮＶＭＦ」）を用いて、ＴＤ方向のスキン層の厚みを任意の１０箇所で測定し、平均値をスキン層の平均厚みとした。
[Average thickness of skin layer]
Using an electron microscope (manufactured by SCARA Co., Ltd.) and filing & two-dimensional measurement software (manufactured by Artley Co., Ltd. “AR-CNVMMF”), the thickness of the skin layer in the TD direction was measured at any 10 locations, and the average value Was the average thickness of the skin layer.
［ＶＳＭを用いた磁気特性の測定］
振動試料型磁気測定装置（型式：ＶＳＭ−Ｃ７−１０Ａ、東英工業（株）製）を用いた。発泡体の測定試料は、内径５ｍｍ、高さ２ｍｍのセルに圧縮して詰めて上記装置にセットした。測定は、印加磁場を加え、１０Ｋ・１０００／４π・Ａ／ｍまで掃引した。次いで、印加磁場を減少させ、ヒステリシスカーブを作製した。このカーブのデータより飽和磁化、残留磁化及び保磁力を求めた。
[Measurement of magnetic properties using VSM]
A vibration sample type magnetometer (model: VSM-C7-10A, manufactured by Toei Kogyo Co., Ltd.) was used. The measurement sample of the foam was compressed and packed into a cell having an inner diameter of 5 mm and a height of 2 mm, and set in the apparatus. The measurement was performed by applying an applied magnetic field and sweeping to 10K · 1000 / 4π · A / m. Next, the applied magnetic field was decreased to prepare a hysteresis curve. Saturation magnetization, residual magnetization, and coercive force were obtained from the data of this curve.
［磁性発泡体の電子顕微鏡による観察方法］
磁性発泡体の観察は、ＦＥ−ＳＥＭ（（株）日立ハイテクノロジーズ製「ＳＵ−８０２０」）を用いて、ＬＡモード、検出器はＵｐｐｅｒを使用し、ＷＤは８ｍｍ、加速電圧１ｋＶ、倍率４５０倍で行った。磁性発泡体は、金蒸着せず、そのままＦＥ−ＳＥＭのサンプルホルダーにセットし、ＬＡモードで撮影することにより、磁性発泡体において、樹脂のみの領域が暗く、磁性粒子が存在する部分は明るく撮影できるように調整した。
[Method of observing magnetic foams with an electron microscope]
The magnetic foam was observed using FE-SEM ("SU-8020" manufactured by Hitachi High-Technologies Corporation), LA mode, detector using Upper, WD 8 mm, acceleration voltage 1 kV, magnification 450 times. I went there. The magnetic foam is not gold-deposited, but is set as it is on the sample holder of the FE-SEM and photographed in the LA mode. In the magnetic foam, the area containing only the resin is dark and the part where the magnetic particles are present is photographed brightly. Adjusted to be possible.
［電磁波シールド性］
実施例で得られた磁性発泡体を縦２００ｍｍ×横２００ｍｍ×厚み５ｍｍに切り出し、ＩＥＣ６２３３３に準拠した伝送減衰率測定方法（マイクロストリップライン）にて測定した。
[Electromagnetic shielding]
The magnetic foams obtained in the Examples were cut into a length of 200 mm, a width of 200 mm, and a thickness of 5 mm, and measured by a transmission attenuation rate measuring method (microstrip line) based on IEC62333.
（測定範囲）
１〜１８ＧＨｚ
（測定用冶具）
マイクロストリップライン冶具
（ネットワークアナイライザ）
Ａｎｒｉｔｓｕ３７２４７Ｃ。
(range of measurement)
1-18GHz
(Measurement jig)
Micro strip line jig (network analyzer)
Anritsu 37247C.
比較例１
ＬＤＰＥ１００重量部、発泡核剤１重量部及び収縮防止剤３重量部を含む樹脂組成物を押出機に投入し、この押出機の途中からイソブタンガス１０重量部を注入した後、発泡適正温度まで冷却し、先端に取り付けた円形状の金型から押出し、発泡体を得た。得られた発泡体は、略円状断面の平均径が１６．１ｍｍである円柱状であり、スキン層の平均厚みは０．０２２ｍｍであった。
Comparative Example 1
A resin composition containing 100 parts by weight of LDPE, 1 part by weight of a foam nucleating agent and 3 parts by weight of an anti-shrink agent is charged into an extruder, and 10 parts by weight of isobutane gas is injected from the middle of the extruder and then cooled to an appropriate foaming temperature. And extruded from a circular mold attached to the tip to obtain a foam. The obtained foam was cylindrical with an average diameter of a substantially circular cross section of 16.1 mm, and the average thickness of the skin layer was 0.022 mm.
実施例１
（マスターバッチの調製）
ＬＤＰＥ３０重量部とハードフェライト粒子７０重量部とをボールミルに投入して１０分間回転しながら混合後、得られた混合物をホッパーからＫＲＣニーダー（（株）栗本鐵工所製）に連続的に投入することで溶融混練し、連続的に排出される混合物（フェライト粒子の含有割合：７０重量％）を水で冷却したのちペレタイザーで切断することでマスターバッチを調製した。
Example 1
(Preparation of masterbatch)
After 30 parts by weight of LDPE and 70 parts by weight of hard ferrite particles are put into a ball mill and mixed while rotating for 10 minutes, the resulting mixture is continuously put into a KRC kneader (manufactured by Kurimoto Steel Works) from a hopper. Then, the mixture was melt kneaded and the continuously discharged mixture (ferrite particle content: 70% by weight) was cooled with water and then cut with a pelletizer to prepare a master batch.
（発泡体の製造）
ＬＤＰＥ１００重量部の代わりに、ＬＤＰＥ９５重量部及びマスターバッチ５重量部を用いる以外は比較例１と同様の方法で発泡体を製造した。得られた発泡体（フェライト粒子含量：３．４重量％）は、略円状断面の平均径が１６ｍｍである円柱状であり、スキン層の平均厚みは０．０２１ｍｍであった。
(Manufacture of foam)
A foam was produced in the same manner as in Comparative Example 1 except that 95 parts by weight of LDPE and 5 parts by weight of master batch were used instead of 100 parts by weight of LDPE. The obtained foam (ferrite particle content: 3.4% by weight) was cylindrical with an average diameter of a substantially circular cross section of 16 mm, and the average thickness of the skin layer was 0.021 mm.
実施例２
ＬＤＰＥ１００重量部の代わりに、ＬＤＰＥ９０重量部及び実施例１で得られたマスターバッチ１０重量部を用いる以外は比較例１と同様にして発泡体（フェライト粒子含量：６．７重量％）を製造した。略円状断面の平均径が１５．２ｍｍである円柱状であり、スキン層の平均厚みは０．０１８ｍｍであった。
Example 2
A foam (ferrite particle content: 6.7% by weight) was produced in the same manner as in Comparative Example 1 except that 90 parts by weight of LDPE and 10 parts by weight of the master batch obtained in Example 1 were used instead of 100 parts by weight of LDPE. . The average diameter of the substantially circular cross section was 15.2 mm, and the skin layer had an average thickness of 0.018 mm.
実施例３
ＬＤＰＥ１００重量部の代わりに、ＬＤＰＥ８０重量部及び実施例１で得られたマスターバッチ２０重量部を用いる以外は比較例１と同様にして発泡体（フェライト粒子含量：１３．５重量％）を製造した。略円状断面の平均径が１５．６ｍｍである円柱状であり、スキン層の平均厚みは０．０１２ｍｍであった。
Example 3
A foam (ferrite particle content: 13.5% by weight) was produced in the same manner as in Comparative Example 1 except that 80 parts by weight of LDPE and 20 parts by weight of the master batch obtained in Example 1 were used instead of 100 parts by weight of LDPE. . The average diameter of the substantially circular cross section was 15.6 mm, and the skin layer had an average thickness of 0.012 mm.
実施例４
ＬＤＰＥ１００重量部の代わりに、ＬＤＰＥ７０重量部及び実施例１で得られたマスターバッチ３０重量部を用いる以外は比較例１と同様にして発泡体（フェライト粒子含量：２０．２重量％）を製造した。略円状断面の平均径が１５．８ｍｍである円柱状であり、スキン層の平均厚みは０．０１２ｍｍであった。
Example 4
A foam (ferrite particle content: 20.2% by weight) was produced in the same manner as in Comparative Example 1 except that 70 parts by weight of LDPE and 30 parts by weight of the master batch obtained in Example 1 were used instead of 100 parts by weight of LDPE. . The average diameter of the substantially circular cross section was 15.8 mm, and the skin layer had an average thickness of 0.012 mm.
実施例５
ＬＤＰＥ１００重量部の代わりに、ＬＤＰＥ６０重量部及び実施例１で得られたマスターバッチ４０重量部を用いる以外は比較例１と同様にして発泡体（フェライト粒子含量：２６．９重量％）を製造した。略円状断面の平均径が１５．８ｍｍである円柱状であり、スキン層の平均厚みは０．０１３ｍｍであった。
Example 5
A foam (ferrite particle content: 26.9% by weight) was produced in the same manner as in Comparative Example 1 except that 60 parts by weight of LDPE and 40 parts by weight of the master batch obtained in Example 1 were used instead of 100 parts by weight of LDPE. . The average diameter of the substantially circular cross section was 15.8 mm, and the skin layer had an average thickness of 0.013 mm.
実施例６
ＬＤＰＥ１００重量部の代わりに、ＬＤＰＥ５０重量部及び実施例１で得られたマスターバッチ５０重量部を用いる以外は比較例１と同様にして発泡体（フェライト粒子含量：３３．７重量％）を製造した。略円状断面の平均径が１２．８ｍｍである円柱状であり、スキン層の平均厚みは０．０１２ｍｍであった。
Example 6
A foam (ferrite particle content: 33.7% by weight) was produced in the same manner as in Comparative Example 1 except that 50 parts by weight of LDPE and 50 parts by weight of the master batch obtained in Example 1 were used instead of 100 parts by weight of LDPE. . The average diameter of the substantially circular cross section was 12.8 mm, and the skin layer had an average thickness of 0.012 mm.
実施例７
ＬＤＰＥ１００重量部の代わりに、ＬＤＰＥ４０重量部及び実施例１で得られたマスターバッチ６０重量部を用いる以外は比較例１と同様にして発泡体（フェライト粒子含量：４０．４重量％）を製造した。略円状断面の平均径が１２．１ｍｍである円柱状であり、スキン層の平均厚みは０．０１０ｍｍであった。
Example 7
A foam (ferrite particle content: 40.4% by weight) was produced in the same manner as in Comparative Example 1 except that 40 parts by weight of LDPE and 60 parts by weight of the master batch obtained in Example 1 were used instead of 100 parts by weight of LDPE. . The average diameter of the substantially circular cross section was a columnar shape of 12.1 mm, and the average thickness of the skin layer was 0.010 mm.
実施例８
ＬＤＰＥ１００重量部の代わりに、ＬＤＰＥ３０重量部及び実施例１で得られたマスターバッチ７０重量部を用いる以外は比較例１と同様にして発泡体（フェライト粒子含量：４７．１重量％）を製造した。略円状断面の平均径が８．６ｍｍである円柱状であり、スキン層の平均厚みは０．０１１ｍｍであった。
Example 8
A foam (ferrite particle content: 47.1% by weight) was produced in the same manner as in Comparative Example 1 except that 30 parts by weight of LDPE and 70 parts by weight of the master batch obtained in Example 1 were used instead of 100 parts by weight of LDPE. . The average diameter of the substantially circular cross section was 8.6 mm, and the skin layer had an average thickness of 0.011 mm.
実施例９
（マスターバッチの調製）
ＬＤＰＥ３０重量部とソフトフェライト粒子７０重量部とをボールミルに投入して１０分間回転しながら混合後、得られた混合物をホッパーからＫＲＣニーダー（（株）栗本鐵工所製）に連続的に投入することで溶融混練し、連続的に排出される混合物（フェライト粒子の含有割合：７０重量％）を水で冷却したのちペレタイザーで切断することでマスターバッチを調製した。
Example 9
(Preparation of masterbatch)
30 parts by weight of LDPE and 70 parts by weight of soft ferrite particles are put into a ball mill and mixed while rotating for 10 minutes, and then the obtained mixture is continuously put into a KRC kneader (manufactured by Kurimoto Steel Co., Ltd.) from a hopper. Then, the mixture was melt kneaded and the continuously discharged mixture (ferrite particle content: 70% by weight) was cooled with water and then cut with a pelletizer to prepare a master batch.
（発泡体の製造）
ＬＤＰＥ４０重量部、得られたマスターバッチ６０重量部、発泡核剤１重量部及び収縮防止剤３重量部を含む樹脂組成物を押出機に投入し、この押出機の途中からイソブタンガス１０重量部を注入した後、発泡適正温度まで冷却し、先端に取り付けたサーキュラーダイから押出し、筒状の発泡体を得た。得られた筒状の発泡体を切り開くことにより、シート状の発泡成形体（フェライト粒子含量：４０．４重量％）を得た。シート厚みが０．７ｍｍであり、スキン層の平均厚みは０．０２１ｍｍであった。
(Manufacture of foam)
A resin composition containing 40 parts by weight of LDPE, 60 parts by weight of the obtained master batch, 1 part by weight of a foam nucleating agent and 3 parts by weight of an anti-shrinkage agent was charged into the extruder, and 10 parts by weight of isobutane gas was added from the middle of the extruder. After the injection, it was cooled to an appropriate foaming temperature and extruded from a circular die attached to the tip to obtain a cylindrical foam. The obtained cylindrical foam was cut open to obtain a sheet-like foamed molded product (ferrite particle content: 40.4% by weight). The sheet thickness was 0.7 mm, and the average thickness of the skin layer was 0.021 mm.
実施例１０
（マスターバッチの調製）
ＬＤＰＥ４０重量部とソフトフェライト粒子３０重量部と還元鉄粉３０重量部とをボールミルに投入して１０分間回転しながら混合後、得られた混合物をホッパーからＫＲＣニーダー（（株）栗本鐵工所製）に連続的に投入することで溶融混練し、連続的に排出される混合物（フェライト粒子の含有割合：３０重量％）を水で冷却したのちペレタイザーで切断することでマスターバッチを調製した。
Example 10
(Preparation of masterbatch)
After 40 parts by weight of LDPE, 30 parts by weight of soft ferrite particles and 30 parts by weight of reduced iron powder were put in a ball mill and mixed while rotating for 10 minutes, the resulting mixture was transferred from a hopper to a KRC kneader (manufactured by Kurimoto Steel Corporation). ) Was continuously melted and kneaded, and a continuously discharged mixture (ferrite particle content: 30% by weight) was cooled with water and then cut with a pelletizer to prepare a master batch.
（発泡体の製造）
マスターバッチの種類を得られたマスターバッチに変更する以外は実施例９と同様にしてシート状の発泡体（フェライト粒子含量：８．７重量％）を製造した。シート厚みは０．８ｍｍであり、スキン層の平均厚みは０．０１３ｍｍであった。
(Manufacture of foam)
A sheet-like foam (ferrite particle content: 8.7% by weight) was produced in the same manner as in Example 9 except that the type of master batch was changed to the obtained master batch. The sheet thickness was 0.8 mm, and the average thickness of the skin layer was 0.013 mm.
実施例及び比較例の評価結果を表１に示す。 The evaluation results of Examples and Comparative Examples are shown in Table 1.
表１の結果から明らかなように、実施例で得られた磁性発泡体は、磁性粒子を含んでいても、発泡倍率が高い。 As is clear from the results in Table 1, the magnetic foams obtained in the examples have a high expansion ratio even if they contain magnetic particles.
実施例５で得られた磁性発泡体の電子顕微鏡写真を図１に示す。局在化したフェライト粒子が確認できた。 An electron micrograph of the magnetic foam obtained in Example 5 is shown in FIG. Localized ferrite particles were confirmed.
実施例９及び比較例１で得られた磁性発泡体の電磁波シールド性を測定した結果を図２に示す。図２から明らかなように、比較例１で得られた磁性発泡体が電磁波シールド性を示さないのに対して、実施例９で得られた磁性発泡体は２〜１８ＧＨｚの電磁波に対してシールド性を示した。 The results of measuring the electromagnetic wave shielding properties of the magnetic foams obtained in Example 9 and Comparative Example 1 are shown in FIG. As is clear from FIG. 2, the magnetic foam obtained in Comparative Example 1 does not exhibit electromagnetic shielding properties, whereas the magnetic foam obtained in Example 9 shields against electromagnetic waves of 2 to 18 GHz. Showed sex.
本発明の磁性発泡体は、磁石（装飾用途・磁石による仮止め用途・固定用途など）、電磁波シールド材（ＰＣやスマートフォン、車載センチ波又は準ミリ波レーダーなどの電磁波を発生する電子機器におけるハウジングの内外壁、家屋や車両などの構造物や内装材など）、電磁波受信体（例えば、レーザー通信やマイクロ波通信などの通信システム、駐車場や有料道路などの料金自動収受システムなどのアンテナなど）などに利用できる。 The magnetic foam of the present invention is a housing in an electronic device that generates electromagnetic waves such as magnets (decorative applications, temporary fixing applications using magnets, fixed applications, etc.), electromagnetic shielding materials (PCs, smartphones, in-vehicle centimeter waves, quasi-millimeter wave radars, etc.) Interior and exterior walls, buildings and interior materials such as houses and vehicles, etc.), electromagnetic wave receivers (for example, communication systems such as laser communication and microwave communication, antennas for automatic toll collection systems such as parking lots and toll roads, etc.) It can be used for
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