JP5518562B2 - Method for producing pre-expanded particles of styrene-modified polyethylene resin - Google Patents
Method for producing pre-expanded particles of styrene-modified polyethylene resin Download PDFInfo
- Publication number
- JP5518562B2 JP5518562B2 JP2010104482A JP2010104482A JP5518562B2 JP 5518562 B2 JP5518562 B2 JP 5518562B2 JP 2010104482 A JP2010104482 A JP 2010104482A JP 2010104482 A JP2010104482 A JP 2010104482A JP 5518562 B2 JP5518562 B2 JP 5518562B2
- Authority
- JP
- Japan
- Prior art keywords
- styrene
- polyethylene resin
- modified polyethylene
- particles
- weight
- 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.)
- Expired - Fee Related
Links
- 239000002245 particle Substances 0.000 title claims description 147
- 229920013716 polyethylene resin Polymers 0.000 title claims description 132
- 238000004519 manufacturing process Methods 0.000 title claims description 24
- 238000005187 foaming Methods 0.000 claims description 53
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 claims description 37
- PPBRXRYQALVLMV-UHFFFAOYSA-N Styrene Chemical group C=CC1=CC=CC=C1 PPBRXRYQALVLMV-UHFFFAOYSA-N 0.000 claims description 30
- 150000003242 quaternary ammonium salts Chemical class 0.000 claims description 30
- 239000006260 foam Substances 0.000 claims description 24
- 239000002612 dispersion medium Substances 0.000 claims description 22
- 238000010097 foam moulding Methods 0.000 claims description 20
- 239000001569 carbon dioxide Substances 0.000 claims description 18
- 229910002092 carbon dioxide Inorganic materials 0.000 claims description 18
- 239000004088 foaming agent Substances 0.000 claims description 18
- 239000000203 mixture Substances 0.000 claims description 12
- 238000010438 heat treatment Methods 0.000 claims description 11
- 239000012298 atmosphere Substances 0.000 claims description 10
- 229910001872 inorganic gas Inorganic materials 0.000 claims description 7
- 230000000379 polymerizing effect Effects 0.000 claims description 5
- 238000000034 method Methods 0.000 description 19
- 229920005989 resin Polymers 0.000 description 18
- 239000011347 resin Substances 0.000 description 18
- 239000007789 gas Substances 0.000 description 14
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 14
- 238000012360 testing method Methods 0.000 description 13
- 229920005672 polyolefin resin Polymers 0.000 description 12
- -1 polypropylene Polymers 0.000 description 11
- 229910001868 water Inorganic materials 0.000 description 11
- CTQNGGLPUBDAKN-UHFFFAOYSA-N O-Xylene Chemical compound CC1=CC=CC=C1C CTQNGGLPUBDAKN-UHFFFAOYSA-N 0.000 description 10
- 239000008096 xylene Substances 0.000 description 10
- 230000006835 compression Effects 0.000 description 9
- 238000007906 compression Methods 0.000 description 9
- 238000006116 polymerization reaction Methods 0.000 description 9
- 239000004698 Polyethylene Substances 0.000 description 8
- 230000006837 decompression Effects 0.000 description 8
- 229920000573 polyethylene Polymers 0.000 description 8
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 7
- 239000003505 polymerization initiator Substances 0.000 description 7
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 6
- WYURNTSHIVDZCO-UHFFFAOYSA-N Tetrahydrofuran Chemical compound C1CCOC1 WYURNTSHIVDZCO-UHFFFAOYSA-N 0.000 description 6
- 238000001816 cooling Methods 0.000 description 6
- 239000002270 dispersing agent Substances 0.000 description 6
- LYRFLYHAGKPMFH-UHFFFAOYSA-N octadecanamide Chemical compound CCCCCCCCCCCCCCCCCC(N)=O LYRFLYHAGKPMFH-UHFFFAOYSA-N 0.000 description 6
- 239000011734 sodium Substances 0.000 description 6
- 229910052708 sodium Inorganic materials 0.000 description 6
- BDHFUVZGWQCTTF-UHFFFAOYSA-M sulfonate Chemical compound [O-]S(=O)=O BDHFUVZGWQCTTF-UHFFFAOYSA-M 0.000 description 6
- 239000004604 Blowing Agent Substances 0.000 description 5
- 125000000217 alkyl group Chemical group 0.000 description 5
- 239000001506 calcium phosphate Substances 0.000 description 5
- 125000004432 carbon atom Chemical group C* 0.000 description 5
- 230000000052 comparative effect Effects 0.000 description 5
- 239000006185 dispersion Substances 0.000 description 5
- 238000000465 moulding Methods 0.000 description 5
- OFBQJSOFQDEBGM-UHFFFAOYSA-N n-pentane Natural products CCCCC OFBQJSOFQDEBGM-UHFFFAOYSA-N 0.000 description 5
- 230000000704 physical effect Effects 0.000 description 5
- QORWJWZARLRLPR-UHFFFAOYSA-H tricalcium bis(phosphate) Chemical compound [Ca+2].[Ca+2].[Ca+2].[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O QORWJWZARLRLPR-UHFFFAOYSA-H 0.000 description 5
- 229940078499 tricalcium phosphate Drugs 0.000 description 5
- 229910000391 tricalcium phosphate Inorganic materials 0.000 description 5
- 235000019731 tricalcium phosphate Nutrition 0.000 description 5
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 description 4
- ATUOYWHBWRKTHZ-UHFFFAOYSA-N Propane Chemical compound CCC ATUOYWHBWRKTHZ-UHFFFAOYSA-N 0.000 description 4
- 239000003431 cross linking reagent Substances 0.000 description 4
- 238000005470 impregnation Methods 0.000 description 4
- 239000000178 monomer Substances 0.000 description 4
- 239000012188 paraffin wax Substances 0.000 description 4
- 150000003254 radicals Chemical class 0.000 description 4
- 229920006395 saturated elastomer Polymers 0.000 description 4
- 230000003068 static effect Effects 0.000 description 4
- PYGXAGIECVVIOZ-UHFFFAOYSA-N Dibutyl decanedioate Chemical compound CCCCOC(=O)CCCCCCCCC(=O)OCCCC PYGXAGIECVVIOZ-UHFFFAOYSA-N 0.000 description 3
- 239000005977 Ethylene Substances 0.000 description 3
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 description 3
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 3
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 description 3
- 125000001797 benzyl group Chemical group [H]C1=C([H])C([H])=C(C([H])=C1[H])C([H])([H])* 0.000 description 3
- 239000001273 butane Substances 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 3
- KYKAJFCTULSVSH-UHFFFAOYSA-N chloro(fluoro)methane Chemical compound F[C]Cl KYKAJFCTULSVSH-UHFFFAOYSA-N 0.000 description 3
- 238000011156 evaluation Methods 0.000 description 3
- 238000004880 explosion Methods 0.000 description 3
- 238000007654 immersion Methods 0.000 description 3
- 238000012986 modification Methods 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- IJDNQMDRQITEOD-UHFFFAOYSA-N n-butane Chemical compound CCCC IJDNQMDRQITEOD-UHFFFAOYSA-N 0.000 description 3
- 229940037312 stearamide Drugs 0.000 description 3
- 239000000454 talc Substances 0.000 description 3
- 229910052623 talc Inorganic materials 0.000 description 3
- YLQBMQCUIZJEEH-UHFFFAOYSA-N tetrahydrofuran Natural products C=1C=COC=1 YLQBMQCUIZJEEH-UHFFFAOYSA-N 0.000 description 3
- 239000004711 α-olefin Substances 0.000 description 3
- MYRTYDVEIRVNKP-UHFFFAOYSA-N 1,2-Divinylbenzene Chemical compound C=CC1=CC=CC=C1C=C MYRTYDVEIRVNKP-UHFFFAOYSA-N 0.000 description 2
- VXNZUUAINFGPBY-UHFFFAOYSA-N 1-Butene Chemical compound CCC=C VXNZUUAINFGPBY-UHFFFAOYSA-N 0.000 description 2
- LIKMAJRDDDTEIG-UHFFFAOYSA-N 1-hexene Chemical compound CCCCC=C LIKMAJRDDDTEIG-UHFFFAOYSA-N 0.000 description 2
- OZAIFHULBGXAKX-UHFFFAOYSA-N 2-(2-cyanopropan-2-yldiazenyl)-2-methylpropanenitrile Chemical compound N#CC(C)(C)N=NC(C)(C)C#N OZAIFHULBGXAKX-UHFFFAOYSA-N 0.000 description 2
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 239000004342 Benzoyl peroxide Substances 0.000 description 2
- OMPJBNCRMGITSC-UHFFFAOYSA-N Benzoylperoxide Chemical compound C=1C=CC=CC=1C(=O)OOC(=O)C1=CC=CC=C1 OMPJBNCRMGITSC-UHFFFAOYSA-N 0.000 description 2
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 description 2
- YNQLUTRBYVCPMQ-UHFFFAOYSA-N Ethylbenzene Chemical compound CCC1=CC=CC=C1 YNQLUTRBYVCPMQ-UHFFFAOYSA-N 0.000 description 2
- PEDCQBHIVMGVHV-UHFFFAOYSA-N Glycerine Chemical compound OCC(O)CO PEDCQBHIVMGVHV-UHFFFAOYSA-N 0.000 description 2
- TWRXJAOTZQYOKJ-UHFFFAOYSA-L Magnesium chloride Chemical compound [Mg+2].[Cl-].[Cl-] TWRXJAOTZQYOKJ-UHFFFAOYSA-L 0.000 description 2
- CSNNHWWHGAXBCP-UHFFFAOYSA-L Magnesium sulfate Chemical compound [Mg+2].[O-][S+2]([O-])([O-])[O-] CSNNHWWHGAXBCP-UHFFFAOYSA-L 0.000 description 2
- BAPJBEWLBFYGME-UHFFFAOYSA-N Methyl acrylate Chemical compound COC(=O)C=C BAPJBEWLBFYGME-UHFFFAOYSA-N 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 239000000654 additive Substances 0.000 description 2
- VSCWAEJMTAWNJL-UHFFFAOYSA-K aluminium trichloride Chemical compound Cl[Al](Cl)Cl VSCWAEJMTAWNJL-UHFFFAOYSA-K 0.000 description 2
- 239000007900 aqueous suspension Substances 0.000 description 2
- TZCXTZWJZNENPQ-UHFFFAOYSA-L barium sulfate Chemical compound [Ba+2].[O-]S([O-])(=O)=O TZCXTZWJZNENPQ-UHFFFAOYSA-L 0.000 description 2
- 235000019400 benzoyl peroxide Nutrition 0.000 description 2
- 238000009835 boiling Methods 0.000 description 2
- 229910000019 calcium carbonate Inorganic materials 0.000 description 2
- 229920001577 copolymer Polymers 0.000 description 2
- 238000004132 cross linking Methods 0.000 description 2
- 238000005520 cutting process Methods 0.000 description 2
- 238000010828 elution Methods 0.000 description 2
- 230000007613 environmental effect Effects 0.000 description 2
- 229930195733 hydrocarbon Natural products 0.000 description 2
- 150000002430 hydrocarbons Chemical class 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- YIXJRHPUWRPCBB-UHFFFAOYSA-N magnesium nitrate Chemical compound [Mg+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O YIXJRHPUWRPCBB-UHFFFAOYSA-N 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
- 230000008018 melting Effects 0.000 description 2
- 239000008188 pellet Substances 0.000 description 2
- YWAKXRMUMFPDSH-UHFFFAOYSA-N pentene Chemical compound CCCC=C YWAKXRMUMFPDSH-UHFFFAOYSA-N 0.000 description 2
- 239000004014 plasticizer Substances 0.000 description 2
- 239000001294 propane Substances 0.000 description 2
- 239000000243 solution Substances 0.000 description 2
- 150000003440 styrenes Chemical class 0.000 description 2
- 239000004094 surface-active agent Substances 0.000 description 2
- VMPHSYLJUKZBJJ-UHFFFAOYSA-N trilaurin Chemical compound CCCCCCCCCCCC(=O)OCC(OC(=O)CCCCCCCCCCC)COC(=O)CCCCCCCCCCC VMPHSYLJUKZBJJ-UHFFFAOYSA-N 0.000 description 2
- QEQBMZQFDDDTPN-UHFFFAOYSA-N (2-methylpropan-2-yl)oxy benzenecarboperoxoate Chemical compound CC(C)(C)OOOC(=O)C1=CC=CC=C1 QEQBMZQFDDDTPN-UHFFFAOYSA-N 0.000 description 1
- KDGNCLDCOVTOCS-UHFFFAOYSA-N (2-methylpropan-2-yl)oxy propan-2-yl carbonate Chemical compound CC(C)OC(=O)OOC(C)(C)C KDGNCLDCOVTOCS-UHFFFAOYSA-N 0.000 description 1
- BNGXYYYYKUGPPF-UHFFFAOYSA-M (3-methylphenyl)methyl-triphenylphosphanium;chloride Chemical compound [Cl-].CC1=CC=CC(C[P+](C=2C=CC=CC=2)(C=2C=CC=CC=2)C=2C=CC=CC=2)=C1 BNGXYYYYKUGPPF-UHFFFAOYSA-M 0.000 description 1
- 125000000923 (C1-C30) alkyl group Chemical group 0.000 description 1
- XLYMOEINVGRTEX-ONEGZZNKSA-N (e)-4-ethoxy-4-oxobut-2-enoic acid Chemical compound CCOC(=O)\C=C\C(O)=O XLYMOEINVGRTEX-ONEGZZNKSA-N 0.000 description 1
- NALFRYPTRXKZPN-UHFFFAOYSA-N 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane Chemical compound CC1CC(C)(C)CC(OOC(C)(C)C)(OOC(C)(C)C)C1 NALFRYPTRXKZPN-UHFFFAOYSA-N 0.000 description 1
- SMZOUWXMTYCWNB-UHFFFAOYSA-N 2-(2-methoxy-5-methylphenyl)ethanamine Chemical compound COC1=CC=C(C)C=C1CCN SMZOUWXMTYCWNB-UHFFFAOYSA-N 0.000 description 1
- XMNIXWIUMCBBBL-UHFFFAOYSA-N 2-(2-phenylpropan-2-ylperoxy)propan-2-ylbenzene Chemical compound C=1C=CC=CC=1C(C)(C)OOC(C)(C)C1=CC=CC=C1 XMNIXWIUMCBBBL-UHFFFAOYSA-N 0.000 description 1
- NIXOWILDQLNWCW-UHFFFAOYSA-N 2-Propenoic acid Natural products OC(=O)C=C NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 description 1
- SBYMUDUGTIKLCR-UHFFFAOYSA-N 2-chloroethenylbenzene Chemical compound ClC=CC1=CC=CC=C1 SBYMUDUGTIKLCR-UHFFFAOYSA-N 0.000 description 1
- DXIJHCSGLOHNES-UHFFFAOYSA-N 3,3-dimethylbut-1-enylbenzene Chemical compound CC(C)(C)C=CC1=CC=CC=C1 DXIJHCSGLOHNES-UHFFFAOYSA-N 0.000 description 1
- JLBJTVDPSNHSKJ-UHFFFAOYSA-N 4-Methylstyrene Chemical compound CC1=CC=C(C=C)C=C1 JLBJTVDPSNHSKJ-UHFFFAOYSA-N 0.000 description 1
- NLHHRLWOUZZQLW-UHFFFAOYSA-N Acrylonitrile Chemical compound C=CC#N NLHHRLWOUZZQLW-UHFFFAOYSA-N 0.000 description 1
- 239000005995 Aluminium silicate Substances 0.000 description 1
- 239000004215 Carbon black (E152) Substances 0.000 description 1
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 1
- XDTMQSROBMDMFD-UHFFFAOYSA-N Cyclohexane Chemical compound C1CCCCC1 XDTMQSROBMDMFD-UHFFFAOYSA-N 0.000 description 1
- YIVJZNGAASQVEM-UHFFFAOYSA-N Lauroyl peroxide Chemical compound CCCCCCCCCCCC(=O)OOC(=O)CCCCCCCCCCC YIVJZNGAASQVEM-UHFFFAOYSA-N 0.000 description 1
- VVQNEPGJFQJSBK-UHFFFAOYSA-N Methyl methacrylate Chemical compound COC(=O)C(C)=C VVQNEPGJFQJSBK-UHFFFAOYSA-N 0.000 description 1
- 235000019482 Palm oil Nutrition 0.000 description 1
- 239000004743 Polypropylene Substances 0.000 description 1
- 239000004793 Polystyrene Substances 0.000 description 1
- 235000021355 Stearic acid Nutrition 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
- 125000005396 acrylic acid ester group Chemical group 0.000 description 1
- 229920001893 acrylonitrile styrene Polymers 0.000 description 1
- 239000003570 air Substances 0.000 description 1
- 125000001931 aliphatic group Chemical group 0.000 description 1
- 125000005211 alkyl trimethyl ammonium group Chemical group 0.000 description 1
- XYLMUPLGERFSHI-UHFFFAOYSA-N alpha-Methylstyrene Chemical compound CC(=C)C1=CC=CC=C1 XYLMUPLGERFSHI-UHFFFAOYSA-N 0.000 description 1
- 235000012211 aluminium silicate Nutrition 0.000 description 1
- DIZPMCHEQGEION-UHFFFAOYSA-H aluminium sulfate (anhydrous) Chemical compound [Al+3].[Al+3].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O DIZPMCHEQGEION-UHFFFAOYSA-H 0.000 description 1
- 150000003863 ammonium salts Chemical class 0.000 description 1
- 150000001450 anions Chemical class 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- 150000004945 aromatic hydrocarbons Chemical class 0.000 description 1
- 239000011324 bead Substances 0.000 description 1
- WPYMKLBDIGXBTP-UHFFFAOYSA-N benzoic acid Chemical compound OC(=O)C1=CC=CC=C1 WPYMKLBDIGXBTP-UHFFFAOYSA-N 0.000 description 1
- VBICKXHEKHSIBG-UHFFFAOYSA-N beta-monoglyceryl stearate Natural products CCCCCCCCCCCCCCCCCC(=O)OCC(O)CO VBICKXHEKHSIBG-UHFFFAOYSA-N 0.000 description 1
- ZFMQKOWCDKKBIF-UHFFFAOYSA-N bis(3,5-difluorophenyl)phosphane Chemical compound FC1=CC(F)=CC(PC=2C=C(F)C=C(F)C=2)=C1 ZFMQKOWCDKKBIF-UHFFFAOYSA-N 0.000 description 1
- CQEYYJKEWSMYFG-UHFFFAOYSA-N butyl acrylate Chemical compound CCCCOC(=O)C=C CQEYYJKEWSMYFG-UHFFFAOYSA-N 0.000 description 1
- 239000000378 calcium silicate Substances 0.000 description 1
- 229910052918 calcium silicate Inorganic materials 0.000 description 1
- OYACROKNLOSFPA-UHFFFAOYSA-N calcium;dioxido(oxo)silane Chemical compound [Ca+2].[O-][Si]([O-])=O OYACROKNLOSFPA-UHFFFAOYSA-N 0.000 description 1
- 235000011089 carbon dioxide Nutrition 0.000 description 1
- UBAZGMLMVVQSCD-UHFFFAOYSA-N carbon dioxide;molecular oxygen Chemical compound O=O.O=C=O UBAZGMLMVVQSCD-UHFFFAOYSA-N 0.000 description 1
- 239000004927 clay Substances 0.000 description 1
- 239000003240 coconut oil Substances 0.000 description 1
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- 238000012669 compression test Methods 0.000 description 1
- 238000007334 copolymerization reaction Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- LSXWFXONGKSEMY-UHFFFAOYSA-N di-tert-butyl peroxide Chemical compound CC(C)(C)OOC(C)(C)C LSXWFXONGKSEMY-UHFFFAOYSA-N 0.000 description 1
- 235000014113 dietary fatty acids Nutrition 0.000 description 1
- LDCRTTXIJACKKU-ONEGZZNKSA-N dimethyl fumarate Chemical compound COC(=O)\C=C\C(=O)OC LDCRTTXIJACKKU-ONEGZZNKSA-N 0.000 description 1
- 229960004419 dimethyl fumarate Drugs 0.000 description 1
- CIKJANOSDPPCAU-UHFFFAOYSA-N ditert-butyl cyclohexane-1,4-dicarboperoxoate Chemical compound CC(C)(C)OOC(=O)C1CCC(C(=O)OOC(C)(C)C)CC1 CIKJANOSDPPCAU-UHFFFAOYSA-N 0.000 description 1
- GVGUFUZHNYFZLC-UHFFFAOYSA-N dodecyl benzenesulfonate;sodium Chemical compound [Na].CCCCCCCCCCCCOS(=O)(=O)C1=CC=CC=C1 GVGUFUZHNYFZLC-UHFFFAOYSA-N 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
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- SUPCQIBBMFXVTL-UHFFFAOYSA-N ethyl 2-methylprop-2-enoate Chemical compound CCOC(=O)C(C)=C SUPCQIBBMFXVTL-UHFFFAOYSA-N 0.000 description 1
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- FEEPBTVZSYQUDP-UHFFFAOYSA-N heptatriacontanediamide Chemical compound NC(=O)CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC(N)=O FEEPBTVZSYQUDP-UHFFFAOYSA-N 0.000 description 1
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- FBAFATDZDUQKNH-UHFFFAOYSA-M iron chloride Chemical compound [Cl-].[Fe] FBAFATDZDUQKNH-UHFFFAOYSA-M 0.000 description 1
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- BAUYGSIQEAFULO-UHFFFAOYSA-L iron(2+) sulfate (anhydrous) Chemical compound [Fe+2].[O-]S([O-])(=O)=O BAUYGSIQEAFULO-UHFFFAOYSA-L 0.000 description 1
- MVFCKEFYUDZOCX-UHFFFAOYSA-N iron(2+);dinitrate Chemical compound [Fe+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O MVFCKEFYUDZOCX-UHFFFAOYSA-N 0.000 description 1
- NLYAJNPCOHFWQQ-UHFFFAOYSA-N kaolin Chemical compound O.O.O=[Al]O[Si](=O)O[Si](=O)O[Al]=O NLYAJNPCOHFWQQ-UHFFFAOYSA-N 0.000 description 1
- 229940057995 liquid paraffin Drugs 0.000 description 1
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- 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
- 229910001629 magnesium chloride Inorganic materials 0.000 description 1
- GVALZJMUIHGIMD-UHFFFAOYSA-H magnesium phosphate Chemical compound [Mg+2].[Mg+2].[Mg+2].[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O GVALZJMUIHGIMD-UHFFFAOYSA-H 0.000 description 1
- 239000004137 magnesium phosphate Substances 0.000 description 1
- 229960002261 magnesium phosphate Drugs 0.000 description 1
- 229910000157 magnesium phosphate Inorganic materials 0.000 description 1
- 235000010994 magnesium phosphates Nutrition 0.000 description 1
- 229910052943 magnesium sulfate Inorganic materials 0.000 description 1
- 235000019341 magnesium sulphate Nutrition 0.000 description 1
- 239000002609 medium Substances 0.000 description 1
- 125000005397 methacrylic acid ester group Chemical group 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- QIQXTHQIDYTFRH-UHFFFAOYSA-N octadecanoic acid Chemical compound CCCCCCCCCCCCCCCCCC(O)=O QIQXTHQIDYTFRH-UHFFFAOYSA-N 0.000 description 1
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- SWAXTRYEYUTSAP-UHFFFAOYSA-N tert-butyl ethaneperoxoate Chemical compound CC(=O)OOC(C)(C)C SWAXTRYEYUTSAP-UHFFFAOYSA-N 0.000 description 1
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Description
本発明は、スチレン改質ポリエチレン系樹脂予備発泡粒子の製造方法に関する。 The present invention relates to a method for producing styrene-modified polyethylene resin pre-expanded particles.
ポリオレフィン系樹脂の発泡体は一般に弾性が高く、繰り返しの応力に対しても歪の回復力が大きいという特徴の他に、耐油性、耐割れ性に優れることから、包装資材や自動車用部材として広く利用されている。しかし、ポリオレフィン系樹脂の発泡体は、剛性が低く、型内発泡成形後の発泡成形体の収縮がおこりやすく、圧縮強度が低いという短所を有している。 Polyolefin resin foams are generally highly elastic and have a high strain recovery ability against repeated stresses, as well as excellent oil resistance and crack resistance, so they are widely used as packaging materials and automotive parts. It's being used. However, polyolefin resin foams have the disadvantages of low rigidity, easy shrinkage of the foamed molding after in-mold foam molding, and low compressive strength.
また、ポリオレフィン系樹脂の中でも、ポリプロピレンなどは、比較的、圧縮強度が高いものの、融点が高く、型内発泡成形時に高い温度が必要であり、設備、エネルギー代などが高価になり、経済性が悪い。また、強度が高い場合には発泡倍率を上げることができるため、軽量化にも有利である。 Among polyolefin resins, polypropylene and the like have a relatively high compressive strength, but have a high melting point and require a high temperature at the time of in-mold foam molding, making equipment and energy costs expensive and economical. bad. In addition, when the strength is high, the expansion ratio can be increased, which is advantageous for weight reduction.
このような欠点を改良する方法として、ポリエチレン系樹脂にスチレン系単量体を含浸させて重合を行った、スチレン改質ポリエチレン系樹脂が知られている。このような方法で作製された樹脂粒子は、特許文献１〜２のように、粒子中の構造、組成を変えることが容易であり、優れた耐薬品性、耐衝撃性、型内発泡成形性を有する樹脂粒子が製造可能である。 As a method for improving such a defect, a styrene-modified polyethylene resin obtained by polymerizing a polyethylene resin by impregnating a styrene monomer is known. The resin particles produced by such a method can easily change the structure and composition in the particles as in Patent Documents 1 and 2, and have excellent chemical resistance, impact resistance, and in-mold foam moldability. Resin particles having can be produced.
スチレン改質ポリエチレン系樹脂予備発泡粒子を製造する方法としては、プロパン、ブタン、ペンタン、フロンガス等の、樹脂の融点以下に沸点を有する有機系発泡剤を溶融樹脂に圧入し、低圧雰囲気下に放出して発泡させる方法（いわゆる「除圧発泡」という方法）や、有機系発泡剤を含浸させた樹脂粒子を、蒸気などによって加熱して発泡させる方法などが開示されている。 Styrene-modified polyethylene resin pre-expanded particles can be produced by injecting an organic blowing agent having a boiling point below the melting point of the resin, such as propane, butane, pentane, or chlorofluorocarbon, into the molten resin and releasing it under a low-pressure atmosphere. And a method of foaming the resin particles impregnated with an organic foaming agent by heating with steam or the like.
ただし、特許文献２には、除圧発泡にて使用できる発泡剤として無機系のガスが例示されているものの、実施例では有機系発泡剤を用いた態様しか具体的には開示されていない。 However, although Patent Document 2 exemplifies inorganic gas as a foaming agent that can be used in decompression foaming, only an embodiment using an organic foaming agent is specifically disclosed in the examples.
プロパンやブタンなどの低沸点有機溶剤の場合、発泡体製造時に爆発性のガスが発生するので、爆発の危険性がある。また、予備発泡粒子や型内発泡成形体にも発泡剤が残留し徐々に漏出するため、保管時にも爆発の危険性があり、また、ＶＯＣの問題も発生する。 In the case of a low-boiling organic solvent such as propane or butane, an explosive gas is generated during the production of the foam, which may cause an explosion. In addition, since the foaming agent remains in the pre-expanded particles and the in-mold foam molded article and gradually leaks, there is a risk of explosion during storage, and a VOC problem occurs.
フロンガスを発泡剤として用いる場合には、爆発の危険性はないが、フロンガスは、環境の観点から問題がある。 When using chlorofluorocarbon as a blowing agent, there is no risk of explosion, but chlorofluorocarbon has a problem from the viewpoint of the environment.
有機系発泡剤を使用した場合の問題点を解決するために、特許文献３では、ポリオレフィン系樹脂、ポリスチレン系樹脂、芳香族ビニル単量体およびラジカル重合開始剤を溶融混合して得られる改質ポリオレフィン系樹脂を炭酸ガスにより発泡させる製造方法が開示されている。特許文献３において炭酸ガスを用いて除圧発泡を行い、改質ポリオレフィン系樹脂予備発泡粒子が得られているが、８ＭＰａの発泡圧力で行われており、設備への負荷が大きくなるため、設備が大掛かりなものとなる。 In order to solve the problems in the case of using an organic foaming agent, Patent Document 3 discloses a modification obtained by melt-mixing a polyolefin resin, a polystyrene resin, an aromatic vinyl monomer, and a radical polymerization initiator. A production method in which a polyolefin resin is foamed with carbon dioxide gas is disclosed. In Patent Document 3, decompression foaming is performed using carbon dioxide gas, and modified polyolefin resin pre-foamed particles are obtained. However, since the foaming pressure is 8 MPa, the load on the equipment increases. Is a big one.
特許文献４において、除圧発泡法を行う際の界面活性剤として塩化アルキルトリメチルアンモニウムなどの第４級アンモニウム塩が挙げられているものの、実施例では使用されておらず、また、発泡性に関する記述もない。 In Patent Document 4, although a quaternary ammonium salt such as alkyltrimethylammonium chloride is mentioned as a surfactant when performing the pressure-reducing foaming method, it is not used in the examples, and description about foamability Nor.
特許文献５では、第４級アンモニウム塩を含有せしめたポリオレフィン系樹脂粒子を、発泡剤として炭酸ガスを用いて除圧発泡することにより、発泡倍率が１０倍以上の発泡粒子が得られている。第４級アンモニウム塩とポリオレフィン系樹脂を溶融混合させており、スチレン改質ポリエチレン系樹脂の場合には、第４級アンモニウム塩とポリエチレン系樹脂を溶融混合させると重合を阻害する恐れがある。また、スチレンで改質した場合の効果は述べられていない。 In Patent Document 5, foamed particles having a foaming ratio of 10 times or more are obtained by subjecting polyolefin resin particles containing a quaternary ammonium salt to decompression foaming using carbon dioxide gas as a foaming agent. The quaternary ammonium salt and the polyolefin resin are melt-mixed. In the case of a styrene-modified polyethylene resin, if the quaternary ammonium salt and the polyethylene resin are melt-mixed, polymerization may be hindered. Moreover, the effect at the time of modifying with styrene is not described.
特許文献６では、発泡剤としてブタン等の炭化水素を用いる発泡において、発泡剤を含浸させた後、第４級アンモニウム塩などの界面活性剤をスチレン改質オレフィン系樹脂粒子に含浸させる製造方法が開示されているが、発泡剤として炭酸ガスは使用されておらず、第４級アンモニウム塩を添加することにより発泡性が改善されるか否かは不明であり、また、別途含浸工程が必要となる。さらに、第４級アンモニウム塩を含浸させるために、高濃度の水溶液（約５０％）が必要とされている。 Patent Document 6 discloses a production method in which a styrene-modified olefin resin particle is impregnated with a surfactant such as a quaternary ammonium salt after impregnating the foaming agent in foaming using a hydrocarbon such as butane as the foaming agent. Although disclosed, carbon dioxide is not used as a foaming agent, and it is unclear whether or not foamability is improved by adding a quaternary ammonium salt, and a separate impregnation step is required. Become. Furthermore, a high concentration aqueous solution (about 50%) is required to impregnate the quaternary ammonium salt.
有機系発泡剤の代替として安全で環境負荷の少ない炭酸ガスを発泡剤として用いてスチレン改質ポリオレフィン系樹脂を発泡する場合には、高い発泡圧力が必要となり、同等の発泡圧力では発泡倍率が低くなる。 When foaming styrene-modified polyolefin resin using carbon dioxide gas, which is safe and has little environmental impact, as an alternative to organic foaming agents, a high foaming pressure is required, and at the same foaming pressure, the foaming ratio is low. Become.
以上のような状況を鑑み、本発明の目的は、炭酸ガスを発泡剤として用いてスチレン改質ポリオレフィン系樹脂を製造する際に、従来よりも高い発泡倍率の発泡粒子を製造する方法を提供することにある。 In view of the circumstances as described above, an object of the present invention is to provide a method for producing expanded particles having a higher expansion ratio than before when producing a styrene-modified polyolefin resin using carbon dioxide as a blowing agent. There is.
本発明者らは、前記課題を解決すべく鋭意検討を行った結果、ポリエチレン系樹脂粒子にスチレン系単量体を含浸、重合させて得られるスチレン改質ポリエチレン系樹脂粒子と第４級アンモニウム塩を耐圧容器中に水系分散媒に分散させて加熱し、前記耐圧容器に発泡剤として炭酸ガスを導入して耐圧容器内を加圧した後、耐圧容器の一端を開放してスチレン改質ポリエチレン系樹脂粒子と水系分散媒を含んでなる混合物を耐圧容器内よりも低圧雰囲気下に放出することにより、第４級アンモニウム塩を分散媒中に添加しなかった場合よりも高い発泡倍率のスチレン改質ポリオレフィン系樹脂が得られることを見出した。さらに、意想外にも、得られたスチレン改質ポリエチレン系樹脂予備発泡粒子を、無機ガスを用いて加圧することにより該スチレン改質ポリエチレン系樹脂予備発泡粒子内の圧力を大気圧よりも高くした後、加熱することにより、更に発泡させることにより得られるスチレン改質ポリエチレン系樹脂予備発泡粒子を型内発泡成形したスチレン改質ポリエチレン系樹脂型内発泡成形体は、第４級アンモニウム塩を分散媒中に添加しなかった場合と比較して、静的圧縮強度が同等、引張強度が高いことを見出し、本発明を完成するに至った。 As a result of intensive studies to solve the above problems, the present inventors have found that styrene-modified polyethylene resin particles obtained by impregnating and polymerizing polyethylene resin particles with a styrene monomer and a quaternary ammonium salt. Is heated in a pressure-resistant container dispersed in an aqueous dispersion medium, carbon dioxide is introduced into the pressure-resistant container as a foaming agent to pressurize the inside of the pressure-resistant container, and then one end of the pressure-resistant container is opened to open a styrene-modified polyethylene system. By releasing a mixture comprising resin particles and an aqueous dispersion medium in a low-pressure atmosphere from inside the pressure vessel, styrene modification with a higher expansion ratio than when no quaternary ammonium salt is added to the dispersion medium. It has been found that a polyolefin-based resin can be obtained. Furthermore, unexpectedly, the pressure inside the styrene-modified polyethylene resin pre-expanded particles obtained by pressurizing the obtained styrene-modified polyethylene resin pre-expanded particles with an inorganic gas was made higher than the atmospheric pressure. Thereafter, the styrene-modified polyethylene resin-in-mold foam-molded product obtained by in-mold foam-molding of styrene-modified polyethylene resin pre-expanded particles obtained by further foaming by heating is obtained by using a quaternary ammonium salt as a dispersion medium. As compared with the case where it was not added to the inside, it was found that the static compressive strength was equal and the tensile strength was high, and the present invention was completed.
すなわち、本発明は、以下の構成よりなる。
［１］ 耐圧容器中にて、ポリエチレン系樹脂粒子にスチレン系単量体を含浸、重合させて得られるスチレン改質ポリエチレン系樹脂粒子および、第４級アンモニウム塩を、水系分散媒に分散させて加熱した後、
前記耐圧容器に発泡剤として炭酸ガスを導入して耐圧容器内を加圧した後、耐圧容器の一端を開放して、スチレン改質ポリエチレン系樹脂粒子および水系分散媒を含んでなる混合物を耐圧容器内よりも低圧雰囲気下に放出する、スチレン改質ポリエチレン系樹脂予備発泡粒子の製造方法であって、
第４級アンモニウム塩の添加量が、スチレン改質ポリエチレン系樹脂粒子１００重量部に対して、０．０１重量部以上４重量部以下である、スチレン改質ポリエチレン系樹脂予備発泡粒子の製造方法。
［２］ ［１］に記載の製造方法によって得られる、スチレン改質ポリエチレン系樹脂予備発泡粒子。
［３］ ［１］に記載の製造方法によって得られるスチレン改質ポリエチレン系樹脂予備発泡粒子を、無機ガスを用いて加圧することにより該スチレン改質ポリエチレン系樹脂予備発泡粒子内の圧力を大気圧よりも高くした後、加熱することにより、更に発泡させることにより得られるスチレン改質ポリエチレン系樹脂予備発泡粒子。
［４］ ［２］または［３］に記載のスチレン改質ポリエチレン系樹脂予備発泡粒子を型内発泡成形して得られるスチレン改質ポリエチレン系樹脂型内発泡成形体。
That is, this invention consists of the following structures.
[1] In a pressure vessel, styrene-modified polyethylene resin particles obtained by impregnating and polymerizing polyethylene resin particles with a styrene monomer and a quaternary ammonium salt are dispersed in an aqueous dispersion medium. After heating
After introducing carbon dioxide as a foaming agent into the pressure vessel and pressurizing the inside of the pressure vessel, one end of the pressure vessel is opened, and a mixture containing styrene-modified polyethylene resin particles and an aqueous dispersion medium is removed. A method for producing styrene-modified polyethylene resin pre-expanded particles that is released in a low-pressure atmosphere than inside,
A method for producing styrene-modified polyethylene resin pre-expanded particles, wherein the addition amount of the quaternary ammonium salt is 0.01 to 4 parts by weight with respect to 100 parts by weight of the styrene-modified polyethylene resin particles.
[2] Styrene-modified polyethylene resin pre-expanded particles obtained by the production method according to [1].
[3] By pressurizing the styrene-modified polyethylene resin pre-expanded particles obtained by the production method according to [1] with an inorganic gas, the pressure in the styrene-modified polyethylene resin pre-expanded particles is set to atmospheric pressure. Styrene-modified polyethylene resin pre-expanded particles obtained by further foaming by heating after heating.
[4] A styrene-modified polyethylene resin in-mold foam-molded product obtained by in-mold foam molding of the styrene-modified polyethylene resin pre-expanded particles according to [2] or [3].
本発明の製造方法では、炭酸ガスを発泡剤として用いて、従来よりも高い発泡倍率のスチレン改質ポリエチレン系樹脂予備発泡粒子を得ることができる。本製造方法で得られる予備発泡粒子を更に発泡させて得られるスチレン改質ポリエチレン系樹脂予備発泡粒子は、型内発泡成形した際に引張強度が優れている。 In the production method of the present invention, styrene-modified polyethylene resin pre-expanded particles having a higher expansion ratio than before can be obtained using carbon dioxide gas as a foaming agent. The styrene-modified polyethylene resin pre-foamed particles obtained by further foaming the pre-foamed particles obtained by this production method have excellent tensile strength when subjected to in-mold foam molding.
本発明のスチレン改質ポリエチレン系樹脂予備発泡粒子の製造方法は、ポリエチレン系樹脂粒子にスチレン系単量体を含浸、重合させたスチレン改質ポリエチレン系樹脂粒子と第４級アンモニウム塩を耐圧容器中に水系分散媒に分散させて、発泡剤として炭酸ガスを用いて発泡させることを特徴とする。 The method for producing styrene-modified polyethylene resin pre-expanded particles of the present invention comprises a polyethylene resin particle impregnated with a styrene monomer and polymerized with the styrene-modified polyethylene resin particle and a quaternary ammonium salt in a pressure vessel. It is characterized by being dispersed in an aqueous dispersion medium and foamed using carbon dioxide gas as a foaming agent.
本発明では、ポリエチレン系樹脂粒子にスチレン系単量体を含浸、重合させたスチレン改質ポリエチレン系樹脂粒子と第４級アンモニウム塩を耐圧容器中に水系分散媒に分散させて加熱し、前記耐圧容器に発泡剤として炭酸ガスを導入して耐圧容器内を加圧した後、耐圧容器の一端を開放してスチレン改質ポリエチレン系樹脂粒子と水系分散媒を含んでなる混合物を耐圧容器内よりも低圧雰囲気下に放出する、いわゆる「除圧発泡」と呼ばれる方法を用いて予備発泡粒子を製造する。 In the present invention, polyethylene resin particles are impregnated with a styrene monomer and polymerized styrene modified polyethylene resin particles and a quaternary ammonium salt are dispersed in an aqueous dispersion medium in a pressure vessel and heated, After introducing carbon dioxide as a foaming agent into the container and pressurizing the inside of the pressure resistant container, one end of the pressure resistant container is opened, and a mixture containing styrene-modified polyethylene resin particles and an aqueous dispersion medium is more than in the pressure resistant container. Pre-expanded particles are produced using a so-called “depressurized foaming” method that discharges in a low-pressure atmosphere.
具体的には、重合反応を行うことによって得られたスチレン改質ポリエチレン系樹脂粒子を、一度耐圧容器より取り出して洗浄・乾燥を行った後に、除圧発泡用の耐圧容器に仕込み、第４級アンモニウム塩と共に水性分散媒に分散させて加熱し、前記耐圧容器に発泡剤として炭酸ガスを導入して耐圧容器内を加圧した後、耐圧容器内の温度および圧力を一定に保ちながら容器の一端を開放し、例えば、開孔径が１〜１０ｍｍのオリフィス等を通して該耐圧容器内よりも低圧雰囲気下、例えば、飽和水蒸気で満たされている雰囲気中に混合物を放出し発泡させることにより、スチレン改質ポリエチレン系樹脂予備発泡粒子を製造することができる。 Specifically, the styrene-modified polyethylene resin particles obtained by carrying out the polymerization reaction are once taken out from the pressure vessel, washed and dried, and then charged into a pressure-resistant vessel for pressure-reducing foaming. After being dispersed in an aqueous dispersion medium together with an ammonium salt and heated, carbon dioxide gas is introduced into the pressure vessel as a blowing agent to pressurize the pressure vessel, and then one end of the vessel is maintained while maintaining the temperature and pressure inside the pressure vessel constant. Styrene modification by releasing and foaming the mixture in a low-pressure atmosphere, for example, in an atmosphere filled with saturated steam, through an orifice having an opening diameter of 1 to 10 mm, etc. Polyethylene resin pre-expanded particles can be produced.
本発明におけるポリエチレン系樹脂粒子を構成するポリエチレン系樹脂は、高密度ポリエチレン、低密度ポリエチレン等のエチレンの単独重合体、エチレンと、例えば、プロピレン、１−ブテン、１−ペンテン、１−ヘキセン等のα−オレフィンや酢酸ビニル、アクリル酸エステル、塩化ビニル等との共重合体があげられる。また、これらポリエチレン系樹脂にアクリロニトリル−スチレン共重合体を配合しても良い。これらの中でも、エチレン・酢酸ビニルの共重合体が、スチレン系単量体の含浸重合時の安定性が高いため、好ましい。 The polyethylene resin constituting the polyethylene resin particles in the present invention is an ethylene homopolymer such as high-density polyethylene or low-density polyethylene, ethylene and, for example, propylene, 1-butene, 1-pentene, 1-hexene, etc. Examples thereof include copolymers with α-olefin, vinyl acetate, acrylic acid ester, vinyl chloride and the like. Moreover, you may mix | blend an acrylonitrile styrene copolymer with these polyethylene-type resin. Among these, an ethylene / vinyl acetate copolymer is preferable because of high stability during the impregnation polymerization of the styrene monomer.
前記ポリエチレン系樹脂は、例えば、押出し機、ニーダー、バンバリーミキサー、ロール等を用いて、予め溶融し、水中或いは空気中に押出し、ストランドカットまたは水中カットすることによりポリエチレン系樹脂粒子となす。ポリエチレン系樹脂粒子の形状は、パウダー、ペレット状等の粒子状態であることが好ましい。この中で、ポリエチレン系樹脂を押し出し、水中カット方式により作製されたペレットが、球形化が容易であり好ましい。 For example, the polyethylene resin is melted in advance using an extruder, a kneader, a Banbury mixer, a roll or the like, extruded into water or air, and cut into strands or underwater to form polyethylene resin particles. The shape of the polyethylene resin particles is preferably a particle state such as powder or pellet. Among these, a pellet produced by extruding a polyethylene resin and using an underwater cutting method is preferable because it can be easily spheroidized.
ポリエチレン系樹脂粒子の平均粒重量は、０．１ｍｇ／粒以上３ｍｇ／粒以下が好適な範囲である。ポリエチレン系樹脂粒子の平均粒重量が０．１ｍｇ／粒より小さい場合は、発泡剤の逸散が激しく、高倍率化させにくくなる傾向があり、３ｍｇ／粒より大きい場合は、成形時の充填性が悪くなる恐れがある。 The average particle weight of the polyethylene resin particles is preferably in the range of 0.1 mg / particle to 3 mg / particle. When the average particle weight of the polyethylene resin particles is smaller than 0.1 mg / particle, the foaming agent tends to dissipate rapidly, making it difficult to increase the magnification. May get worse.
本発明においては、成形性の向上、発泡倍率の向上など、目的に応じて、可塑剤、気泡調整剤等の各種添加剤を使用することができる。 In the present invention, various additives such as a plasticizer and a bubble regulator can be used depending on the purpose, such as improvement of moldability and improvement of foaming ratio.
可塑剤としては、例えば、ステアリン酸トリグリセライド、パルミチン酸トリグリセライド、ラウリン酸トリグリセライド、ステアリン酸ジグリセライド、ステアリン酸モノグリセライド等の脂肪酸グリセライド、ヤシ油、パーム油、パーム核油等の植物油、ジオクチルアジペート、セバシン酸ジブチル等の脂肪族エステル、流動パラフィン、シクロヘキサン等の有機炭化水素、トルエン、エチルベンゼン等の有機芳香族炭化水素等があげられ、これらは併用しても何ら差し支えない。 Examples of the plasticizer include fatty acid glycerides such as stearic acid triglyceride, palmitic acid triglyceride, lauric acid triglyceride, stearic acid diglyceride, and stearic acid monoglyceride, vegetable oils such as coconut oil, palm oil, and palm kernel oil, dioctyl adipate, dibutyl sebacate And the like, organic hydrocarbons such as liquid paraffin and cyclohexane, and organic aromatic hydrocarbons such as toluene and ethylbenzene. These may be used in combination.
気泡調整剤としては、例えば、メチレンビスステアリン酸アマイド、エチレンビスステアリン酸アマイド等の脂肪族ビスアマイドやステアリン酸アミド等の有機系気泡調整剤、タルク、シリカ、珪酸カルシウム、炭酸カルシウム等の無機系気泡調整剤等があげられる。 Examples of the foam regulator include organic foam regulators such as aliphatic bisamides and stearamide such as methylene bis stearic acid amide and ethylene bis stearic acid amide, inorganic foams such as talc, silica, calcium silicate, and calcium carbonate. Examples thereof include regulators.
気泡調整剤の中でも、無機系気泡調整剤を使用することが好ましく、好ましい使用量としてはポリエチレン系樹脂１００重量部に対し、０．０１重量部以上０．５重量部以下である。無機系気泡調整剤が０．０１重量部より少ないと安定的に気泡を生成することが困難となる場合があり、０．５重量部より多く使用した場合は型内発泡成形時の融着が悪化する傾向がある。 Among the bubble regulators, it is preferable to use an inorganic bubble regulator, and the preferred amount is 0.01 parts by weight or more and 0.5 parts by weight or less with respect to 100 parts by weight of the polyethylene resin. When the amount of the inorganic cell regulator is less than 0.01 parts by weight, it may be difficult to stably generate bubbles. When the amount is more than 0.5 parts by weight, fusion during in-mold foam molding may occur. There is a tendency to get worse.
また、これらの各種添加剤は、重合時や発泡剤含浸時に添加し、含浸させることもできるし、前記ポリエチレン系樹脂に予め混ぜ込むこともできる。 These various additives can be added and impregnated at the time of polymerization or at the time of impregnation with a foaming agent, or can be mixed in advance with the polyethylene resin.
本発明において、スチレン改質ポリエチレン系樹脂粒子を含浸、重合させる方法としては、攪拌機を具備した容器内に仕込んだポリエチレン系樹脂粒子を含む水性懸濁液に、スチレン系単量体を連続的にまたは断続的に添加することにより、ポリエチレン系樹脂粒子にスチレン系単量体を含浸させ、重合させる。 In the present invention, as a method of impregnating and polymerizing styrene-modified polyethylene resin particles, a styrene monomer is continuously added to an aqueous suspension containing polyethylene resin particles charged in a container equipped with a stirrer. Alternatively, by intermittent addition, the polyethylene resin particles are impregnated with the styrene monomer and polymerized.
重合において、添加するスチレン系単量体の添加速度を任意に選択することにより、スチレン改質ポリエチレン系樹脂予備発泡粒子の重量平均分子量に調整することが可能である。重合温度は７０℃以上９０℃以下であると、所望の重量平均分子量であるスチレン改質ポリエチレン系樹脂予備発泡粒子が得られるため、好ましい。 In the polymerization, the weight average molecular weight of the styrene-modified polyethylene resin pre-expanded particles can be adjusted by arbitrarily selecting the addition rate of the styrene monomer to be added. A polymerization temperature of 70 ° C. or higher and 90 ° C. or lower is preferred because styrene-modified polyethylene resin pre-expanded particles having a desired weight average molecular weight can be obtained.
本発明において用いられるスチレン系単量体としては、例えば、スチレン、α−メチルスチレン、パラメチルスチレン、ｔ−ブチルスチレン、クロルスチレン等のスチレン系誘導体を主成分とするものである。また、例えば、メチルアクリレート、ブチルアクリレート、メチルメタクリレート、エチルメタクリレート等のアクリル酸およびメタクリル酸のエステル、あるいはアクリロニトリル、ジメチルフマレート、エチルフマレート等のスチレン系誘導体と共重合が可能な単量体を、１種または２種以上併用してもよい。更に、ジビニルベンゼン、アルキレングリコールジメタクリレート等の多官能性単量体を併用することもできる。 Examples of the styrenic monomer used in the present invention include styrene derivatives such as styrene, α-methylstyrene, paramethylstyrene, t-butylstyrene, chlorostyrene, and the like as main components. Further, for example, monomers capable of copolymerization with acrylic acid and methacrylic acid esters such as methyl acrylate, butyl acrylate, methyl methacrylate, and ethyl methacrylate, or styrene derivatives such as acrylonitrile, dimethyl fumarate, and ethyl fumarate. You may use together 1 type (s) or 2 or more types. Furthermore, polyfunctional monomers such as divinylbenzene and alkylene glycol dimethacrylate can be used in combination.
ポリエチレン系樹脂粒子１００重量部に対して、スチレン系単量体を好ましくは１５０重量部以上４００重量部以下、更に好ましくは、１８０重量部以上３００重量部重合させる。当該範囲内であれば、型内発泡成形性や物性が良好であるスチレン改質ポリエチレン系樹脂予備発泡粒子となる傾向がある。 The styrene monomer is preferably polymerized in an amount of 150 to 400 parts by weight, more preferably 180 to 300 parts by weight, with respect to 100 parts by weight of the polyethylene resin particles. If it is in the said range, there exists a tendency to become a styrene modified polyethylene resin pre-expanded particle which is excellent in in-mold foam moldability and physical properties.
ポリエチレン系樹脂粒子にスチレン系単量体を重合させるのに際し、重合開始剤を使用することが好ましい。
使用しうる重合開始剤としては、一般に熱可塑性重合体の製造に用いられるラジカル発生型重合開始剤を用いることができ、代表的なものとしては、例えば、過酸化ベンゾイル、ラウロイルパーオキサイド、ｔ−ブチルパーピバレート、ｔ−ブチルパーオキシイソプロピルカーボネート、ジ−ｔ−ブチルパーオキシヘキサハイドロテレフタレート、１，１−ジ（ｔ−ブチルパーオキシ）３，３，５−トリメチルシクロヘキサン、１，１−ジ（ｔ−ブチルパーオキシ）シクロヘキサンなどの有機過酸化物や、アゾビスイソブチロニトリル、アゾビスジメチルバレロニトリルなどのアゾ化合物が挙げられる。これらの重合開始剤は単独もしくは２種以上を混合して用いることができる。
重量平均分子量は、重合開始剤の量と反応温度により調整できる。
A polymerization initiator is preferably used when the styrene monomer is polymerized on the polyethylene resin particles.
As the polymerization initiator that can be used, radical generating polymerization initiators generally used for the production of thermoplastic polymers can be used. Typical examples include benzoyl peroxide, lauroyl peroxide, t- Butyl perpivalate, t-butyl peroxyisopropyl carbonate, di-t-butyl peroxyhexahydroterephthalate, 1,1-di (t-butylperoxy) 3,3,5-trimethylcyclohexane, 1,1-di Examples thereof include organic peroxides such as (t-butylperoxy) cyclohexane, and azo compounds such as azobisisobutyronitrile and azobisdimethylvaleronitrile. These polymerization initiators can be used alone or in admixture of two or more.
The weight average molecular weight can be adjusted by the amount of the polymerization initiator and the reaction temperature.
重合開始剤の使用量は、スチレン系単量体１００重量部に対して、０．０５重量部以上１．０重量部以下であることが好ましく、０．１重量部以上０．５重量部以下であることがさらに好ましい。 The amount of the polymerization initiator used is preferably 0.05 parts by weight or more and 1.0 parts by weight or less, and 0.1 parts by weight or more and 0.5 parts by weight or less with respect to 100 parts by weight of the styrene monomer. More preferably.
本発明においては、スチレン改質ポリエチレン系樹脂型内発泡成形体の強度を向上させるために、スチレン改質ポリエチレン系樹脂粒子内を架橋させることが好ましい。 In the present invention, in order to improve the strength of the styrene-modified polyethylene resin-in-mold foam-molded product, the inside of the styrene-modified polyethylene resin particles is preferably cross-linked.
架橋を行うためには、ラジカル種発生型架橋剤を使用することができる。このようなラジカル種発生型架橋剤としては、ジ−ｔ−ブチルパーオキサイド（１０時間半減期温度：１２３℃）、ジクミルパーオキサイド（１０時間半減期温度：１１６℃）、ｔ−ブチルパーオキシベンゾエート（１０時間半減期温度：１０４℃）、ｔ−ブチルパーオキシアセテート（１０時間半減期温度：１０２℃）、２，２−ビスーｔ−ブチルパーオキシブタン（１０時間半減期温度：１０３℃）等が挙げられる。
これら架橋剤は、スチレン系単量体の添加前あるいはスチレン系単量体と共に重合系に添加することができる。架橋反応は、通常は重合時に行うが、除圧発泡を行う場合、除圧発泡時に行ってもよい。
In order to perform crosslinking, a radical species generating type crosslinking agent can be used. Examples of such radical species-generating crosslinking agents include di-t-butyl peroxide (10-hour half-life temperature: 123 ° C.), dicumyl peroxide (10-hour half-life temperature: 116 ° C.), and t-butyl peroxy. Benzoate (10-hour half-life temperature: 104 ° C.), t-butyl peroxyacetate (10-hour half-life temperature: 102 ° C.), 2,2-bis-t-butyl peroxybutane (10-hour half-life temperature: 103 ° C.) Etc.
These crosslinking agents can be added to the polymerization system before addition of the styrene monomer or together with the styrene monomer. The cross-linking reaction is usually performed at the time of polymerization, but when performing decompression foaming, it may be performed at the time of decompression foaming.
本発明では、除圧発泡時にスチレン改質ポリエチレン系樹脂粒子と共に、第４級アンモニウム塩を水系分散媒に添加することにより、従来よりも高い発泡倍率のスチレン改質ポリエチレン系樹脂予備発泡粒子を得ることができる。また、本発明の製造方法にて得られる予備発泡粒子を、さらに発泡させて得られるスチレン改質ポリエチレン系樹脂予備発泡粒子は、型内発泡成形した際に引張強度に優れる成形体を得ることができる。 In the present invention, by adding a quaternary ammonium salt to the aqueous dispersion medium together with the styrene-modified polyethylene resin particles during decompression foaming, styrene-modified polyethylene resin pre-expanded particles having a higher expansion ratio than before are obtained. be able to. In addition, the styrene-modified polyethylene resin pre-foamed particles obtained by further foaming the pre-foamed particles obtained by the production method of the present invention can obtain a molded article having excellent tensile strength when subjected to in-mold foam molding. it can.
本発明に用いられる第４級アンモニウム塩は、一般式（１）〔（Ｒ１）４Ｎ〕＋Ｘ− で表すことができる。
一般式（１）中、Ｒ１は同一でも異なっていても良く、分岐していてもよい炭素数１〜３０のアルキル基またはベンジル基であることが望ましい。さらに、４個のＲ１のうち、少なくとも１個は炭素数１０〜２０のアルキル基であり、その他は炭素数１〜３のアルキル基またはベンジル基であることが望ましい。より望ましくは、４個のＲ１のうち２個は炭素数１０〜２０のアルキル基であり、残りの２個は炭素数１〜３のアルキル基またはベンジル基である。
一般式（１）中、Ｘ−は一般的なアニオンであれば何でも良く、望ましくは、入手の容易性、値段、環境負荷、水系分散媒液への影響、等の点から、Ｆ−、Ｃｌ−、Ｂｒ−、ＲＣＯＯ−、ＲＯＳＯ３ −であり、より望ましくは、Ｃｌ−である（なお、Ｒは炭素数１〜３のアルキル基である）。
The quaternary ammonium salt used in the present invention can be represented by the general formula (1) [(R 1 ) 4 N] + X − .
In general formula (1), R 1 may be the same or different and is preferably a C 1-30 alkyl group or benzyl group which may be branched. Further, it is desirable that at least one of the four R 1 is an alkyl group having 10 to 20 carbon atoms, and the other is an alkyl group having 1 to 3 carbon atoms or a benzyl group. More preferably, two of the four R 1 are alkyl groups having 10 to 20 carbon atoms, and the remaining two are an alkyl group having 1 to 3 carbon atoms or a benzyl group.
In the general formula (1), X − may be any general anion, and preferably F − and Cl in terms of availability, cost, environmental load, influence on aqueous dispersion medium, and the like. -, Br -, RCOO -, ROSO 3 - a, more preferably, Cl - is (Incidentally, R is an alkyl group having 1 to 3 carbon atoms).
本発明における第４級アンモニウム塩の添加量は、スチレン改質ポリエチレン系樹脂粒子１００重量部に対して、０．０１重量部以上４重量部以下であることが好ましく、０．０１重量部以上２重量部以下であることがより好ましく、０．１重量部以上１重量部以下がさらに好ましい。第４級アンモニウム塩の添加量が０．０１重量部未満の場合には、スチレン改質ポリエチレン系樹脂粒子の発泡倍率が向上しない可能性があり、４重量部超の場合には、水系分散混合物の分散性が悪化する（樹脂粒子が塊状化する）場合があり、さらに、廃水中の第４級アンモニウム塩濃度が高くなり、廃水処理の手間がかかる恐れがある。 The addition amount of the quaternary ammonium salt in the present invention is preferably 0.01 parts by weight or more and 4 parts by weight or less, and 0.01 parts by weight or more and 2 parts by weight or less with respect to 100 parts by weight of the styrene-modified polyethylene resin particles. More preferably, it is 0.1 part by weight or less and further preferably 1 part by weight or less. When the addition amount of the quaternary ammonium salt is less than 0.01 parts by weight, the expansion ratio of the styrene-modified polyethylene resin particles may not be improved, and when it exceeds 4 parts by weight, the aqueous dispersion mixture The dispersibility of the resin may deteriorate (resin particles agglomerate), and the concentration of the quaternary ammonium salt in the wastewater becomes high, which may require time for wastewater treatment.
除圧発泡に用いられる水系分散媒としては、樹脂粒子を溶解させないものであれば、特に限定はなく、例えば、水、メタノール、エタノール、グリセリン、エチレングリコール等が挙げられ、これらを併用しても良い。とりわけ、水を使用することが好ましい。水系分散媒の使用量は、スチレン改質ポリエチレン系樹脂粒子１００重量部に対して、５０重量部以上１０００重量部以下であることが好ましい。 The aqueous dispersion medium used for decompression foaming is not particularly limited as long as it does not dissolve the resin particles, and examples thereof include water, methanol, ethanol, glycerin, ethylene glycol, and the like. good. In particular, it is preferable to use water. The amount of the aqueous dispersion medium used is preferably 50 parts by weight or more and 1000 parts by weight or less with respect to 100 parts by weight of the styrene-modified polyethylene resin particles.
スチレン改質ポリエチレン系樹脂粒子を水系分散媒に分散させる際には、樹脂同士の付着を防止するために、分散剤を使用することが好ましい。分散剤として、例えば、第三リン酸カルシウム、リン酸マグネシウム、塩基性炭酸マグネシウム、炭酸カルシウム、硫酸バリウム、カオリン、タルク、クレー等の無機系分散剤が挙げられる。 When dispersing the styrene-modified polyethylene resin particles in the aqueous dispersion medium, it is preferable to use a dispersant in order to prevent adhesion between the resins. Examples of the dispersant include inorganic dispersants such as tricalcium phosphate, magnesium phosphate, basic magnesium carbonate, calcium carbonate, barium sulfate, kaolin, talc, and clay.
必要に応じて、例えば、ドデシルベンゼンスルホン酸ソーダ、ｎ−パラフィンスルホン酸ソーダ、α−オレフィンスルホン酸ソーダ、硫酸マグネシウム、硝酸マグネシウム、塩化マグネシウム、硫酸アルミニウム、硝酸アルミニウム、塩化アルミニウム、硫酸鉄、硝酸鉄、塩化鉄等の分散助剤を併用することが好ましい。 As necessary, for example, sodium dodecylbenzenesulfonate, sodium n-paraffin sulfonate, sodium α-olefin sulfonate, magnesium sulfate, magnesium nitrate, magnesium chloride, aluminum sulfate, aluminum nitrate, aluminum chloride, iron sulfate, iron nitrate It is preferable to use a dispersion aid such as iron chloride in combination.
これらの中でも、第三リン酸カルシウムとｎ−パラフィンスルホン酸ソーダの併用が、水系分散媒の安定性、分散剤の除去の容易性の点から、更に好ましい。 Among these, combined use of tricalcium phosphate and sodium n-paraffin sulfonate is more preferable from the viewpoint of the stability of the aqueous dispersion medium and the ease of removal of the dispersant.
分散剤や分散助剤の使用量は、その種類や、用いられるスチレン改質ポリエチレン系樹脂の種類と使用量によって異なるが、通常、分散媒１００重量部に対して分散剤０．２重量部以上３重量部以下が好ましく、分散助剤０．００１重量部以上０．１重量部以下がより好ましい。 The amount of dispersant and dispersion aid used varies depending on the type and type and amount of styrene-modified polyethylene resin used, but usually 0.2 parts by weight or more of dispersant with respect to 100 parts by weight of the dispersion medium. The amount is preferably 3 parts by weight or less, more preferably 0.001 part by weight or more and 0.1 part by weight or less.
前記のようにして耐圧容器内に調製された混合物は、撹拌下、発泡温度まで昇温され、炭酸ガスによって発泡圧力まで加圧させた後、好ましくは５分以上１８０分以下、より好ましくは１０分以上６０分以下の間、温度、圧力を保持する。発泡温度、発泡圧力で保持されたスチレン改質ポリエチレン系樹脂粒子を、耐圧容器の一端（一般的には耐圧容器の下部）に設けられたバルブを開放して、耐圧容器内よりも低圧雰囲気下（通常は大気圧下）に放出することにより、スチレン改質ポリエチレン系樹脂予備発泡粒子を得ることができる。 The mixture prepared in the pressure vessel as described above is heated to the foaming temperature under stirring and pressurized to the foaming pressure with carbon dioxide gas, and is preferably 5 minutes to 180 minutes, more preferably 10 minutes. The temperature and pressure are maintained for not less than 60 minutes and not more than 60 minutes. Open the valve provided at one end of the pressure vessel (generally, the lower part of the pressure vessel) and place the styrene-modified polyethylene resin particles held at the foaming temperature and pressure in a lower pressure atmosphere than inside the pressure vessel. By releasing to (usually under atmospheric pressure), styrene-modified polyethylene resin pre-expanded particles can be obtained.
発泡温度としては、１２０℃以上１８０℃以下が好ましく、１３０℃以上１６５℃以下がより好ましい。発泡温度が１８０℃よりも高い場合には、設備への負荷が大きい上に、樹脂の分解が生じる可能性がある。発泡温度が１２０℃より低い場合には、発泡倍率が低くなる傾向があり、目的の発泡倍率のスチレン改質ポリエチレン系樹脂予備発泡粒子が得られない可能性がある。 The foaming temperature is preferably 120 ° C. or higher and 180 ° C. or lower, and more preferably 130 ° C. or higher and 165 ° C. or lower. When the foaming temperature is higher than 180 ° C., the load on the equipment is large and the resin may be decomposed. When the foaming temperature is lower than 120 ° C., the foaming ratio tends to be low, and the styrene-modified polyethylene resin pre-foamed particles having the target foaming ratio may not be obtained.
発泡圧力としては、２ＭＰａ以上１０ＭＰａ以下が好ましく、２．５ＭＰａ以上７ＭＰａ以下がより好ましく、３ＭＰａ以上５ＭＰａ以下がさらに好ましい。発泡圧力が１０ＭＰａより高い場合には設備の負荷が大きく、設備が高価になる傾向がある。発泡圧力が２ＭＰａより低い場合には、発泡倍率が低くなる傾向があり、目的の発泡倍率のスチレン改質ポリエチレン系樹脂予備発泡粒子が得られない可能性がある。 The foaming pressure is preferably 2 MPa or more and 10 MPa or less, more preferably 2.5 MPa or more and 7 MPa or less, and further preferably 3 MPa or more and 5 MPa or less. When the foaming pressure is higher than 10 MPa, the load on the equipment is large and the equipment tends to be expensive. When the foaming pressure is lower than 2 MPa, the expansion ratio tends to be low, and the styrene-modified polyethylene resin pre-expanded particles having the target expansion ratio may not be obtained.
スチレン改質ポリエチレン系樹脂粒子を低圧雰囲気下に放出する際、流量調整、倍率バラつき低減などの目的で、１〜１０ｍｍφの開口オリフィスを通して放出することもできる。また、発泡倍率を高くする目的で、前記低圧雰囲気が飽和水蒸気で満たされていることが好ましい。 When the styrene-modified polyethylene resin particles are discharged under a low-pressure atmosphere, they can be discharged through an opening orifice of 1 to 10 mmφ for the purpose of adjusting the flow rate and reducing the variation in magnification. For the purpose of increasing the expansion ratio, the low-pressure atmosphere is preferably filled with saturated steam.
本発明におけるスチレン改質ポリエチレン系樹脂予備発泡粒子は、キシレンに不溶なゲルを含むことが望ましい。キシレンに不溶なゲル分量は、スチレン改質ポリエチレン系樹脂予備発泡粒子中、１０重量％以上５０重量％以下であることが好ましく、１５重量％以上４０重量％以下がさらに好ましい。ゲル分量が当該範囲内であると、型内発泡成形を行う場合、予備発泡粒子を高倍化しやすく、成形性、物性が良好なスチレン改質ポリエチレン系樹脂型内発泡成形体を得ることができる。
なお、キシレンに不溶なゲル分量は、以下のようにして測定される。２００メッシュの金網袋中に０．４ｇの予備発泡樹脂粒子を入れ、大気圧下で沸騰させたキシレン４５０ｍｌ中に金網袋を２時間浸漬して冷却後に一旦、取り出し、更に新たな沸騰させたキシレン４５０ｍｌ中に金網袋樹脂を１時間浸漬して冷却後に、キシレンから取り出す。その後、同様に２時間、１時間の浸漬、溶出を繰り返し、その後、常温下で１晩液切りした後に、１５０℃のオーブン中で１時間乾燥させ、常温まで自然冷却させ、冷却後の金網袋中の残留分をゲル分とした。ゲル分量の予備発泡樹脂粒子量に対する重量比率を、ゲル成分量とする。
The styrene-modified polyethylene resin pre-expanded particles in the present invention desirably contain a gel insoluble in xylene. The amount of gel insoluble in xylene is preferably 10% by weight or more and 50% by weight or less, and more preferably 15% by weight or more and 40% by weight or less in the pre-expanded particles of styrene-modified polyethylene resin. When the gel content is within the above range, when performing in-mold foam molding, it is possible to obtain a styrene-modified polyethylene resin in-mold foam molded article that is easy to double the pre-foamed particles and has good moldability and physical properties.
The amount of gel insoluble in xylene is measured as follows. Put 0.4 g of pre-expanded resin particles in a 200-mesh wire mesh bag, immerse the wire mesh bag in 450 ml of xylene boiled under atmospheric pressure for 2 hours, take it out after cooling, and then add new boiled xylene The wire mesh bag resin is immersed in 450 ml for 1 hour, cooled, and then taken out from xylene. After that, the immersion and elution were repeated for 2 hours and 1 hour in the same manner, and then the liquid was drained overnight at room temperature, then dried in an oven at 150 ° C. for 1 hour, allowed to cool naturally to room temperature, and the wire mesh bag after cooling. The residual content in the gel was the gel content. The weight ratio of the gel content to the amount of the pre-expanded resin particles is defined as the gel component amount.
本発明におけるスチレン改質ポリエチレン系樹脂予備発泡粒子は、テトラヒドロフランに可溶な成分の重量平均分子量が１０万以上２５万以下であることが好ましい。当該範囲内であると、型内発泡成形を行う場合に型内発泡成形性が良好である傾向にある。
なお、テトラヒドロフランに可溶な成分の重量平均分子量とは、スチレン改質ポリエチレン系樹脂予備発泡粒子０．０２ｇを、常温のテトラヒドロフラン２０ｍｌに２４時間浸漬させて抽出される成分を、０．２μｍのフィルターでろ過した後、ゲル・パーミエーション・クロマトグラフィーにより、標準ポリスチレン試料を基準として求めた値である。
The styrene-modified polyethylene resin pre-expanded particles in the present invention preferably have a weight average molecular weight of a component soluble in tetrahydrofuran of 100,000 to 250,000. Within the range, in-mold foam moldability tends to be good when performing in-mold foam molding.
The weight average molecular weight of the component soluble in tetrahydrofuran refers to the component extracted by immersing 0.02 g of styrene-modified polyethylene resin pre-expanded particles in 20 ml of tetrahydrofuran at room temperature for 24 hours. It is the value calculated | required on the basis of the standard polystyrene sample by the gel permeation chromatography after filtering by.
本発明におけるスチレン改質ポリエチレン系樹脂予備発泡粒子の独立気泡率は、８８％以上１００％以下であることが好ましく、９２％以上１００％以下がより好ましく、９５％以上１００％以下がさらに好ましい。独立気泡率が当該範囲内にない場合、型内発泡成形時に蒸気加熱による発泡性に劣り、得られるスチレン改質ポリエチレン系樹脂型内発泡成形体が収縮したり物性低下が生じる恐れがある。 The closed cell ratio of the styrene-modified polyethylene resin pre-expanded particles in the present invention is preferably 88% to 100%, more preferably 92% to 100%, and still more preferably 95% to 100%. When the closed cell ratio is not within the above range, foamability by steam heating is inferior at the time of in-mold foam molding, and the resulting styrene-modified polyethylene resin in-mold foam-molded product may shrink or deteriorate physical properties.
本発明におけるスチレン改質ポリエチレン系樹脂予備発泡粒子の発泡倍率は、３倍以上６０倍以下が好ましく、６倍以上４０倍以下がより好ましい。発泡倍率が当該範囲外の場合、連続気泡率が上昇するなど、型内発泡成形の成形性およびチレン改質ポリエチレン系樹脂型内発泡成形体の物性が低下する恐れがある。 The expansion ratio of the pre-expanded styrene-modified polyethylene resin particles in the present invention is preferably 3 to 60 times, more preferably 6 to 40 times. When the expansion ratio is out of the above range, the moldability of in-mold foam molding and the physical properties of the styrene-modified polyethylene resin in-mold foam molding may be lowered, for example, the open cell ratio is increased.
本発明においては、より高い発泡倍率のビーズを得るために、一旦、前記の発泡方法により得られる（好ましくは、発泡倍率が３倍以上２５倍以下の）スチレン改質ポリエチレン系樹脂予備発泡粒子を、無機ガスを用いて加圧することにより、該スチレン改質ポリエチレン系樹脂予備発泡粒子内の圧力を大気圧よりも高くした後、加熱することにより、更に発泡させるという、いわゆる「二段発泡法」を用いることができる。二段発泡法を用いることにより、成形機に高負荷をかける（高い発泡圧力を要する）ことなく、より高い発泡倍率のスチレン改質ポリエチレン系樹脂予備発泡粒子を得ることができる。 In the present invention, in order to obtain beads having a higher expansion ratio, styrene-modified polyethylene resin pre-expanded particles once obtained by the above-described foaming method (preferably having a expansion ratio of 3 to 25 times) are used. The so-called “two-stage foaming method” in which the pressure inside the styrene-modified polyethylene resin pre-foamed particles is increased from atmospheric pressure by pressurizing with an inorganic gas and then further foamed by heating. Can be used. By using the two-stage foaming method, it is possible to obtain styrene-modified polyethylene resin pre-foamed particles having a higher foaming ratio without placing a high load on the molding machine (requiring high foaming pressure).
本発明の二段発泡法に用いられる無機ガスとしては、窒素、酸素、炭酸ガス、空気、ヘリウム、アルゴン、水、などがあげられる。これらは、単独で用いてもよいし、２種以上を組み合わせて用いてもよい。これらのうちでも、コスト、安全性の点から、空気が好ましい。 Examples of the inorganic gas used in the two-stage foaming method of the present invention include nitrogen, oxygen, carbon dioxide gas, air, helium, argon, and water. These may be used alone or in combination of two or more. Among these, air is preferable from the viewpoint of cost and safety.
本発明の二段発泡法における予備発泡粒子内の圧力としては、０．１０ＭＰａ以上０．７ＭＰａ以下が好ましい。
二段発泡法により発泡倍率を高くする場合、二段発泡前の予備発泡粒子の発泡倍率に対して７倍以内の発泡倍率にすることが望ましい。
The pressure in the pre-expanded particles in the two-stage foaming method of the present invention is preferably 0.10 MPa or more and 0.7 MPa or less.
When the expansion ratio is increased by the two-stage foaming method, it is desirable to set the expansion ratio within 7 times the expansion ratio of the pre-expanded particles before the two-stage expansion.
本発明におけるスチレン改質ポリエチレン系樹脂予備発泡粒子の平均気泡径は、５０μｍ以上８００μｍ以下であることが好ましく、７０μｍ以上６００μｍ以下がより好ましく、１００μｍ以上５００μｍ以下がさらに好ましい。平均気泡径が当該範囲内であると、型内発泡成形を行う場合に成形性が良好であり、物性も良好なスチレン改質ポリエチレン系樹脂型内発泡成形体を得ることができる。
なお、平均気泡径は、任意の３０個のスチレン改質ポリエチレン系樹脂予備発泡粒子において、ＪＩＳ Ｋ６４０２に従って測定した値である。
The average cell diameter of the styrene-modified polyethylene resin pre-expanded particles in the present invention is preferably from 50 μm to 800 μm, more preferably from 70 μm to 600 μm, and even more preferably from 100 μm to 500 μm. When the average cell diameter is within this range, a styrene-modified polyethylene resin in-mold foam molded article having good moldability and good physical properties can be obtained when performing in-mold foam molding.
The average cell diameter is a value measured according to JIS K6402 for any 30 styrene-modified polyethylene resin pre-expanded particles.
本発明のスチレン改質ポリエチレン系樹脂予備発泡粒子を型内発泡成形する場合には、イ）スチレン改質ポリエチレン系樹脂予備発泡粒子をそのまま用いる方法、ロ）予めスチレン改質ポリエチレン系樹脂予備発泡粒子中に空気等の無機ガスを圧入し、発泡能を付与する方法、ハ）スチレン改質ポリエチレン系樹脂予備発泡粒子を圧縮状態で金型内に充填して型内発泡成形する方法、などの方法が使用しうる。 When the styrene-modified polyethylene resin pre-expanded particles of the present invention are subjected to in-mold foam molding, a) a method in which the styrene-modified polyethylene resin pre-expanded particles are used as they are, and b) a styrene-modified polyethylene resin pre-expanded particles in advance. A method of injecting an inorganic gas such as air into the foam to give foaming ability, c) A method of filling the styrene-modified polyethylene resin pre-expanded particles into a mold in a compressed state and foam-molding in the mold Can be used.
本発明のスチレン改質ポリエチレン系樹脂予備発泡粒子からスチレン改質ポリエチレン系樹脂型内発泡成形体を型内発泡成形する具体的方法としては、例えば、（１）予めスチレン改質ポリエチレン系樹脂予備発泡粒子を耐圧容器内で空気加圧し、スチレン改質ポリエチレン系樹脂予備発泡粒子に空気を圧入することにより発泡能を付与した後、（２）２つの金型よりなる閉鎖しうるが密閉し得ない成形空間内に充填し、水蒸気などを加熱媒体としてゲージ圧０．０３〜０．２ＭＰａ程度の水蒸気圧で３〜７０秒程度の加熱時間で成形し、スチレン改質ポリエチレン系樹脂予備発泡粒子同士を融着させた後、（３）金型を水冷などにより冷却した後、金型を開くことにより、スチレン改質ポリエチレン系樹脂型内発泡成形体を得る方法、などが挙げられる。 As a specific method for foam-molding a styrene-modified polyethylene resin in-mold foam from the styrene-modified polyethylene resin pre-foamed particles of the present invention, for example, (1) styrene-modified polyethylene resin pre-foamed in advance After the particles are air-pressurized in a pressure-resistant container and air is injected into the styrene-modified polyethylene resin pre-expanded particles to give foaming ability, (2) two molds can be closed but cannot be sealed Filled into the molding space, molded with water vapor or the like as a heating medium at a water pressure of about 0.03 to 0.2 MPa and a heating time of about 3 to 70 seconds, and pre-expanded particles of styrene-modified polyethylene resin (3) A method of obtaining a styrene-modified polyethylene resin in-mold foam molded article by opening the mold after the mold is cooled by water cooling, etc. And the like.
本発明におけるスチレン改質ポリエチレン系樹脂型内発泡成形体の密度は、１０ｋｇ／ｍ３以上３００ｋｇ／ｍ３以下であることが好ましく、１５ｋｇ／ｍ３以上２５０ｋｇ／ｍ３以下がより好ましく、１５ｋｇ／ｍ３以上１５０ｋｇ／ｍ３以下がさらに好ましい。 The density of the foam-molded styrene-modified polyethylene resin mold in the present invention is preferably 10 kg / m 3 or more and 300 kg / m 3 or less, more preferably 15 kg / m 3 or more and 250 kg / m 3 or less, and 15 kg / m 3 or less. m 3 or more 150 kg / m 3 or less is more preferred.
本発明におけるスチレン改質ポリエチレン系樹脂型内発泡成形体は、同程度の密度の成形体を比較した場合、静的圧縮強度を高くすることができる。
なお、静的圧縮強度とは、型内発泡成形体を徐々に圧縮していったときに生じる各歪時の応力である。静的圧縮応力は、ＮＤＳ Ｚ ０５０４−６９に準拠し、５０ｍｍ×５０ｍｍ×２５ｍｍのサンプルを１０ｍｍ／ｍｉｎの試験速度で圧縮して、応力を測定した。
The styrene-modified polyethylene resin-in-mold foam-molded product in the present invention can increase the static compressive strength when compared with molded products having similar densities.
The static compressive strength is a stress at each strain generated when the in-mold foam molded body is gradually compressed. The static compressive stress was measured in accordance with NDS Z 0504-69 by compressing a sample of 50 mm × 50 mm × 25 mm at a test speed of 10 mm / min.
本発明におけるスチレン改質ポリエチレン系樹脂型内発泡成形体は、同程度の密度の成形体を比較した場合、引張強度を高くすることができる。
なお、引張強度とは、型内発泡成形体を引っ張った際に生じる最大応力である。引張強度は、ＪＩＳ−Ｋ６７６７に準拠し、測定部が長さ４０ｍｍ、幅１０ｍｍ、厚み１０ｍｍのダンベル型サンプルを５００ｍｍ／ｍｉｎの試験速度で引張り、破断するまでの最大応力を測定した。
The styrene-modified polyethylene resin-in-mold foam-molded product according to the present invention can have high tensile strength when compared with molded products having similar densities.
The tensile strength is the maximum stress generated when the in-mold foam molded product is pulled. The tensile strength was based on JIS-K6767, and the measurement part pulled a dumbbell-shaped sample having a length of 40 mm, a width of 10 mm, and a thickness of 10 mm at a test speed of 500 mm / min, and measured the maximum stress until breaking.
以下に実施例および比較例を挙げるが、これによって本発明は制限されるものではない。 Examples and Comparative Examples are given below, but the present invention is not limited thereby.
なお、測定、評価については、以下の通り実施した。 In addition, about measurement and evaluation, it implemented as follows.
＜発泡倍率＞
スチレン改質ポリエチレン系樹脂予備発泡粒子の重量ｗ（ｇ）およびエタノール水没体積ｖ（ｃｍ３）を求め、発泡前のスチレン改質ポリエチレン系樹脂粒子の密度ｄ（ｇ／ｃｍ３）から次式により求めたものである。
発泡倍率＝ｄ×ｖ／ｗ。
<Foaming ratio>
The weight w (g) of the styrene-modified polyethylene resin pre-foamed particles and the ethanol submerged volume v (cm 3 ) are obtained, and the density d (g / cm 3 ) of the styrene-modified polyethylene resin particles before foaming is obtained by the following equation. It is what I have sought.
Foaming ratio = d × v / w.
＜独立気泡率＞
空気比較式比重計（ＢＥＣＫＭＡＮ社製、９３０型）を用いて、得られたスチレン改質ポリエチレン系樹脂予備発泡粒子の独立気泡体積を求め、かかる独立気泡体積を別途エタノール浸漬法で求めた見かけ体積で除することにより、独立気泡率を算出した。
<Closed cell ratio>
Using an air-comparing hydrometer (BECKMAN, model 930), the closed cell volume of the obtained styrene-modified polyethylene resin pre-expanded particles was determined, and the apparent cell volume was separately determined by the ethanol immersion method. The closed cell ratio was calculated by dividing by.
＜平均気泡径＞
得られたスチレン改質ポリエチレン系樹脂予備発泡粒子の中から任意に３０個の予備発泡粒子を取り出し、ＪＩＳ Ｋ６４０２に準拠して気泡径を測定し、平均気泡径を算出した。
<Average bubble diameter>
Thirty pre-expanded particles were arbitrarily taken out from the obtained styrene-modified polyethylene resin pre-expanded particles, the bubble diameter was measured according to JIS K6402, and the average bubble diameter was calculated.
＜キシレンに不溶なゲル量＞
２００メッシュの金網袋中に０．４ｇの予備発泡樹脂粒子を入れ、大気圧下で沸騰させたキシレン４５０ｍｌ中に金網袋を２時間浸漬して冷却後に一旦、取り出し、更に新たな沸騰させたキシレン４５０ｍｌ中に金網袋を１時間浸漬して冷却後に、キシレンから取り出す。その後、同様に２時間、１時間の浸漬、溶出を繰り返し、その後、常温下で１晩液切りした後に、１５０℃のオーブン中で１時間乾燥させ、常温まで自然冷却させ、冷却後の金網袋中の残留分をゲル分とした。ゲル分量の予備発泡樹脂粒子量に対する重量比率を、ゲル成分量とする。
<Amount of gel insoluble in xylene>
Put 0.4 g of pre-expanded resin particles in a 200-mesh wire mesh bag, immerse the wire mesh bag in 450 ml of xylene boiled under atmospheric pressure for 2 hours, take it out after cooling, and then add new boiled xylene The wire mesh bag is immersed in 450 ml for 1 hour, cooled, and taken out from xylene. After that, the immersion and elution were repeated for 2 hours and 1 hour in the same manner, and then the liquid was drained overnight at room temperature, then dried in an oven at 150 ° C. for 1 hour, allowed to cool naturally to room temperature, and the wire mesh bag after cooling. The residual content in the gel was the gel content. The weight ratio of the gel content to the amount of the pre-expanded resin particles is defined as the gel component amount.
＜スチレン改質ポリエチレン系樹脂型内発泡成形体の表面性＞
得られたスチレン改質ポリエチレン系樹脂型内発泡成形体の外観を、以下の基準で判断した。
○：予備発泡粒子間の隙間が見当たらない。
△：所々隙間があるが、全体としては許容レベルである。
×：隙間が多い。
<Surface properties of styrene-modified polyethylene resin in-mold foam molding>
The appearance of the obtained styrene-modified polyethylene resin-in-mold foam-molded product was judged according to the following criteria.
○: There are no gaps between the pre-expanded particles.
Δ: There are gaps in some places, but the overall level is acceptable.
X: There are many gaps.
＜５０％圧縮時の圧縮応力＞
ＮＤＳ Ｚ ０５０４−６９に準拠し、得られた型内スチレン改質ポリエチレン系樹脂発泡成形体からバーチカルスライサーを用いて、５０ｍｍ×５０ｍｍ×２５ｍｍに切り出し、すべての面が切り出し面となるような試験片を作製し、密度を測定した。
５０ｍｍ×５０ｍｍの面が上下になるようにして１０ｍｍ／ｍｉｎの試験速度で圧縮試験を実施し、５０％圧縮時の圧縮応力を測定した。
なお、試験片の密度は、重量ｗ（ｇ）、縦、横、厚みの長さから体積ｖ（ｃｍ３）を求め、次式により求めたものである。
試験片密度＝ｗ／ｖ（ｇ／ｃｍ３）
<Compression stress at 50% compression>
In accordance with NDS Z 0504-69, the obtained in-mold styrene-modified polyethylene resin foam molded article was cut into 50 mm × 50 mm × 25 mm using a vertical slicer, and a test piece in which all surfaces became cut surfaces Was fabricated and the density was measured.
A compression test was performed at a test speed of 10 mm / min so that the surface of 50 mm × 50 mm was up and down, and the compression stress at 50% compression was measured.
In addition, the density of the test piece was obtained from the following equation by determining the volume v (cm 3 ) from the weight w (g), length, width, and thickness.
Test piece density = w / v (g / cm 3 )
＜引張時の最大応力＞
ＪＩＳ Ｋ６７６７に準拠し、得られた型内スチレン改質ポリエチレン系樹脂型内発泡成形体からバーチカルスライサーを用いて、全ての面が切り出し面となるよう１２０ｍｍ×２５ｍｍ×１０ｍｍに切り出し、密度を測定する。
密度を測定した切り出し片を、糸鋸を用いて、測定部が長さ４０ｍｍ、幅１０ｍｍ、厚み１０ｍｍのダンベル型に切り抜き、試験片を作成する。試験片を５００ｍｍ／ｍｉｎの試験速度で引張試験を実施し、引張時の最大応力を測定した。
なお、試験片の密度は、重量ｗ（ｇ）、縦、横、厚みの長さから体積ｖ（ｃｍ３）を求め、次式により求めたものである。
試験片密度＝ｗ／ｖ（ｇ／ｃｍ３）
<Maximum stress during tension>
In accordance with JIS K6767, from the obtained in-mold styrene-modified polyethylene resin-in-mold foam-molded body, using a vertical slicer, cut out to 120 mm × 25 mm × 10 mm so that all surfaces become cut surfaces, and measure the density. .
The cut piece whose density was measured was cut out into a dumbbell shape having a measuring section of 40 mm in length, 10 mm in width, and 10 mm in thickness using a yarn saw to prepare a test piece. The test piece was subjected to a tensile test at a test speed of 500 mm / min, and the maximum stress during tension was measured.
In addition, the density of the test piece was obtained from the following equation by determining the volume v (cm 3 ) from the weight w (g), length, width, and thickness.
Test piece density = w / v (g / cm 3 )
（製造例）［スチレン改質ポリエチレン系樹脂粒子の製造］
ポリエチレン系樹脂として、住友化学株式会社製、エバテートＦ１１０３−１を使用し、ポリエチレン系樹脂１００重量部に対してタルク０．２重量部を混合して、押出機内で溶融混合して造粒し、水中に押出した直後にカッティングすることにより、粒重量約１ｍｇ／粒の球状のポリエチレン系樹脂粒子を作製した。
続いて、６Ｌオートクレーブ中に、水１５０重量部、第３リン酸カルシウム２重量部、α−オレフィンスルホン酸ソーダ０．０４８重量部およびポリエチレン系樹脂粒子３５重量部を懸濁させ、スチレン単量体１７．５重量部に、重合開始剤として過酸化ベンゾイル０．２６重量部（１０時間半減期温度：７４℃）、ラジカル種発生型架橋剤としてｔ−ブチルパーオキシベンゾエート（１０時間半減期温度：１０４℃）０．６５重量部を溶解させた溶液を添加した。その後、この水系懸濁液を７０℃まで昇温し、３０分間維持することにより、ポリエチレン系樹脂粒子にスチレン単量体溶液を含浸させた。
更に、８５℃まで昇温し、スチレン単量体４７．５重量部を２時間４０分かけて反応系中に滴下して重合を行い、追加終了１時間後に１２０℃まで昇温して５０分保持し、冷却後、洗浄・脱水・乾燥することにより、スチレン改質ポリエチレン系樹脂粒子を得た。
(Production example) [Production of styrene-modified polyethylene resin particles]
As the polyethylene resin, Sumitomo Chemical Co., Ltd., Evaate F1103-1 is used, 0.2 parts by weight of talc is mixed with 100 parts by weight of the polyethylene resin, and melt-mixed in the extruder and granulated. By cutting immediately after extrusion into water, spherical polyethylene resin particles having a particle weight of about 1 mg / particle were produced.
Subsequently, 150 parts by weight of water, 2 parts by weight of tricalcium phosphate, 0.048 parts by weight of sodium α-olefin sulfonate and 35 parts by weight of polyethylene resin particles are suspended in a 6 L autoclave, and the styrene monomer 17. To 5 parts by weight, 0.26 parts by weight of benzoyl peroxide as a polymerization initiator (10 hour half-life temperature: 74 ° C.), t-butyl peroxybenzoate as a radical species-generating crosslinking agent (10 hour half-life temperature: 104 ° C.) ) A solution having 0.65 parts by weight dissolved therein was added. Thereafter, this aqueous suspension was heated to 70 ° C. and maintained for 30 minutes, whereby polyethylene resin particles were impregnated with a styrene monomer solution.
Further, the temperature was raised to 85 ° C., 47.5 parts by weight of a styrene monomer was dropped into the reaction system over 2 hours and 40 minutes to perform polymerization, and after 1 hour from the completion of the addition, the temperature was raised to 120 ° C. The styrene-modified polyethylene resin particles were obtained by holding, cooling, washing, dehydrating and drying.
（実施例１〜６）
［予備発泡粒子の作製］
１０Ｌオートクレーブに、水３００重量部、第３リン酸カルシウム２．０重量部、ｎ−パラフィンスルホン酸ソーダ０．０２重量部、スチレン改質ポリエチレン系樹脂粒子１００重量部、セバシン酸ジブチル０．５重量部、表１に示す種類、量の第４級アンモニウム塩を仕込み、炭酸ガスにて１．０ＭＰａまで加圧した。これらの混合物を１５５℃まで加温した後、炭酸ガスにより３．０ＭＰａまで加圧し、５０分間保持した。温度、圧力を保持しつつ耐圧容器下部のバルブを開いて、水分散物を開孔径４．０ｍｍφのオリフィス板を通して飽和水蒸気で満たされた筒に放出することによって、スチレン改質ポリエチレン系樹脂予備発泡粒子を得た。得られた予備発泡粒子について、発泡倍率、独立気泡率を測定した。結果は表１に示した。
得られたスチレン改質ポリエチレン系樹脂予備発泡粒子内に、空気含浸により０．１５〜０．５ＭＰａの内圧を付与し、０．０４〜０．０８ＭＰａ（ゲージ圧）の蒸気により加熱し、発泡倍率約２０倍のスチレン改質ポリエチレン系樹脂予備発泡粒子を得た。得られた予備発泡粒子について、独立気泡率、平均気泡径、ゲル量を測定した。結果は表２に示した。
［型内発泡成形体の作製］
次に、耐圧容器内で空気加圧し０．１４〜０．１７ＭＰａの内圧を付与したスチレン改質ポリエチレン系樹脂予備発泡粒子を４００ｍｍ×３００ｍｍ×６０ｍｍの金型に充填し、予備発泡粒子同士を圧力０．１０ＭＰａ（ゲージ圧）の水蒸気で加熱、融着させ、スチレン改質ポリエチレン系樹脂型内発泡成形体を得た。
得られた型内発泡成形体について、５０％圧縮時の圧縮応力、引張時の最大応力、それぞれの試験片密度を測定した。結果は表２に示した。
(Examples 1-6)
[Preparation of pre-expanded particles]
In a 10 L autoclave, 300 parts by weight of water, 2.0 parts by weight of tricalcium phosphate, 0.02 parts by weight of sodium n-paraffin sulfonate, 100 parts by weight of styrene-modified polyethylene resin particles, 0.5 parts by weight of dibutyl sebacate, The kind and amount of quaternary ammonium salt shown in Table 1 were charged and pressurized to 1.0 MPa with carbon dioxide gas. These mixtures were heated to 155 ° C., then pressurized to 3.0 MPa with carbon dioxide gas, and held for 50 minutes. While maintaining the temperature and pressure, the valve at the lower part of the pressure vessel is opened, and the aqueous dispersion is discharged through a orifice plate having a hole diameter of 4.0 mm into a cylinder filled with saturated steam, thereby pre-foaming a styrene-modified polyethylene resin. Particles were obtained. About the obtained pre-expanded particle, the expansion ratio and the closed cell ratio were measured. The results are shown in Table 1.
The obtained styrene-modified polyethylene resin pre-expanded particles are given an internal pressure of 0.15 to 0.5 MPa by air impregnation and heated with steam of 0.04 to 0.08 MPa (gauge pressure), and the expansion ratio About 20-fold styrene-modified polyethylene resin pre-expanded particles were obtained. The obtained pre-expanded particles were measured for closed cell ratio, average cell diameter, and gel amount. The results are shown in Table 2.
[Production of in-mold foam moldings]
Next, pre-expanded styrene-modified polyethylene resin pre-expanded particles, which are pressurized with air in a pressure-resistant container and applied with an internal pressure of 0.14 to 0.17 MPa, are filled in a 400 mm × 300 mm × 60 mm mold, and the pre-expanded particles are pressurized together. Heating and fusing with water vapor of 0.10 MPa (gauge pressure) gave a styrene-modified polyethylene resin in-mold foam molded product.
About the obtained in-mold foam molded article, the compression stress at the time of 50% compression, the maximum stress at the time of tension, and the density of each test piece were measured. The results are shown in Table 2.
（実施例７）
１０Ｌオートクレーブに、水３００重量部、第３リン酸カルシウム２．０重量部、ｎ−パラフィンスルホン酸ソーダ０．０２重量部、スチレン改質ポリエチレン系樹脂粒子１００重量部、セバシン酸ジブチル０．５重量部、表１に示す種類、量の第４級アンモニウム塩を仕込み、炭酸ガスにて１．０ＭＰａまで加圧した。これらの混合物を１５５℃まで加温した後、炭酸ガスにより６．０ＭＰａまで加圧し、５０分間保持した。温度、圧力を保持しつつ耐圧容器下部のバルブを開いて、水分散物を開孔径４．０ｍｍφのオリフィス板を通して飽和水蒸気で満たされた筒に放出することによって、スチレン改質ポリエチレン系樹脂予備発泡粒子を得た。得られた予備発泡粒子について、発泡倍率、独立気泡率、平均気泡径、ゲル量を測定した。結果は表１、２に示した。
［型内発泡成形体の作製］
次に、得られたスチレン改質ポリエチレン系樹脂予備発泡粒子を４００ｍｍ×３００ｍｍ×６０ｍｍの金型に充填し、予備発泡粒子同士を圧力０．１０ＭＰａ（ゲージ圧）の水蒸気で加熱、融着させ、スチレン改質ポリエチレン系樹脂型内発泡成形体を得た。
得られた型内発泡成形体について、５０％圧縮時の圧縮応力、引張時の最大応力、それぞれの試験片密度を測定した。結果は表２に示した。
(Example 7)
In a 10 L autoclave, 300 parts by weight of water, 2.0 parts by weight of tricalcium phosphate, 0.02 parts by weight of sodium n-paraffin sulfonate, 100 parts by weight of styrene-modified polyethylene resin particles, 0.5 parts by weight of dibutyl sebacate, The kind and amount of quaternary ammonium salt shown in Table 1 were charged and pressurized to 1.0 MPa with carbon dioxide gas. These mixtures were heated to 155 ° C., pressurized to 6.0 MPa with carbon dioxide gas, and held for 50 minutes. While maintaining the temperature and pressure, the valve at the lower part of the pressure vessel is opened, and the aqueous dispersion is discharged through a orifice plate having a hole diameter of 4.0 mm into a cylinder filled with saturated steam, thereby pre-foaming a styrene-modified polyethylene resin. Particles were obtained. About the obtained pre-expanded particles, the expansion ratio, the closed cell ratio, the average cell diameter, and the gel amount were measured. The results are shown in Tables 1 and 2.
[Production of in-mold foam moldings]
Next, the obtained styrene-modified polyethylene resin pre-expanded particles are filled into a 400 mm × 300 mm × 60 mm mold, and the pre-expanded particles are heated and fused with water vapor at a pressure of 0.10 MPa (gauge pressure), A styrene-modified polyethylene resin-in-mold foam-molded product was obtained.
About the obtained in-mold foam molded article, the compression stress at the time of 50% compression, the maximum stress at the time of tension, and the density of each test piece were measured. The results are shown in Table 2.
（比較例１）
第４級アンモニウム塩を添加していない以外は、実施例１〜６と同様の方法にて、スチレン改質ポリエチレン系樹脂予備発泡粒子、型内発泡成形体を得た。実施例と同様の評価を行い、結果を表１、２に示した。
(Comparative Example 1)
A styrene-modified polyethylene resin pre-expanded particle and an in-mold foam molded article were obtained in the same manner as in Examples 1 to 6 except that the quaternary ammonium salt was not added. The same evaluation as in the example was performed, and the results are shown in Tables 1 and 2.
（比較例２）
第４級アンモニウム塩の代わりにステアリン酸アミドを２重量部添加した以外は、実施例１〜６と同様の方法にて、スチレン改質ポリエチレン系樹脂予備発泡粒子、型内発泡成形体を得た。実施例と同様の評価を行い、結果を表１、２に示した。
(Comparative Example 2)
Except that 2 parts by weight of stearamide was added instead of the quaternary ammonium salt, styrene-modified polyethylene resin pre-expanded particles and in-mold expanded molded articles were obtained in the same manner as in Examples 1-6. . The same evaluation as in the example was performed, and the results are shown in Tables 1 and 2.
（比較例３）
第４級アンモニウム塩の添加量を５重量部に変更した以外は、実施例１〜６と同様の方法にて、改質ポリエチレン系樹脂予備発泡粒子の製造を行った。しかしながら、オートクレーブ内で樹脂が塊化し、予備発泡粒子を得られなかった。
(Comparative Example 3)
Modified polyethylene resin pre-expanded particles were produced in the same manner as in Examples 1 to 6, except that the amount of quaternary ammonium salt added was changed to 5 parts by weight. However, the resin agglomerated in the autoclave and pre-expanded particles could not be obtained.
発泡剤として炭酸ガスを用い、第４級アンモニウム塩をスチレン改質ポリエチレン系樹脂と共に水分散媒に添加した場合には、第４級アンモニウム塩を添加しなかった場合に比べて除圧発泡での発泡倍率が２０％前後高くなった。二段発泡後の予備発泡粒子を型内成形して得られる型内発泡成形体の圧縮強度は第４級アンモニウム塩を添加しなかった場合に比べて同等であり、引張強度は１０％前後高くなった。
また、比較例２では、ステアリン酸アミドをスチレン改質ポリエチレン系樹脂と共に水分散媒に添加し、発泡倍率が高くなったものの、二段発泡後の予備発泡粒子を型内成形して得られる型内発泡成形体の圧縮強度が大幅に低下した。このように、水分散媒中に、スチレン改質ポリエチレン系樹脂と共に、第４級アンモニウム塩を添加する本発明の製造方法では、発泡倍率が高くなる上に、機械的強度の低下もみられない。
When carbonic acid gas is used as the blowing agent and the quaternary ammonium salt is added to the aqueous dispersion medium together with the styrene-modified polyethylene resin, the decompression foaming is less than when the quaternary ammonium salt is not added. The expansion ratio was increased by about 20%. The compression strength of the in-mold foam molded product obtained by molding the pre-foamed particles after the two-stage foaming in the mold is equivalent to that when no quaternary ammonium salt is added, and the tensile strength is about 10% higher. became.
In Comparative Example 2, stearamide was added to an aqueous dispersion medium together with a styrene-modified polyethylene resin to increase the expansion ratio, but a mold obtained by in-mold molding of pre-expanded particles after two-stage expansion The compressive strength of the inner foamed molded product was greatly reduced. Thus, in the production method of the present invention in which the quaternary ammonium salt is added to the water dispersion medium together with the styrene-modified polyethylene resin, the expansion ratio is increased and the mechanical strength is not decreased.
Claims (4)
前記耐圧容器に発泡剤として炭酸ガスを導入して耐圧容器内を加圧した後、耐圧容器の一端を開放して、スチレン改質ポリエチレン系樹脂粒子および水系分散媒を含んでなる混合物を耐圧容器内よりも低圧雰囲気下に放出する、スチレン改質ポリエチレン系樹脂予備発泡粒子の製造方法であって、
第４級アンモニウム塩の添加量が、スチレン改質ポリエチレン系樹脂粒子１００重量部に対して、０．０１重量部以上４重量部以下である、スチレン改質ポリエチレン系樹脂予備発泡粒子の製造方法。 In a pressure vessel, after styrene-modified polyethylene resin particles obtained by impregnating and polymerizing polyethylene resin particles with a styrene monomer and quaternary ammonium salt are dispersed in an aqueous dispersion medium and heated. ,
After introducing carbon dioxide as a foaming agent into the pressure vessel and pressurizing the inside of the pressure vessel, one end of the pressure vessel is opened, and a mixture containing styrene-modified polyethylene resin particles and an aqueous dispersion medium is removed. A method for producing styrene-modified polyethylene resin pre-expanded particles that is released in a low-pressure atmosphere than inside,
A method for producing styrene-modified polyethylene resin pre-expanded particles, wherein the addition amount of the quaternary ammonium salt is 0.01 to 4 parts by weight with respect to 100 parts by weight of the styrene-modified polyethylene resin particles.
A styrene-modified polyethylene resin in-mold foam molded product obtained by in-mold foam molding of the styrene-modified polyethylene resin pre-expanded particles according to claim 2.
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