JPH0432098B2 - - Google Patents
Info
- Publication number
- JPH0432098B2 JPH0432098B2 JP2068274A JP6827490A JPH0432098B2 JP H0432098 B2 JPH0432098 B2 JP H0432098B2 JP 2068274 A JP2068274 A JP 2068274A JP 6827490 A JP6827490 A JP 6827490A JP H0432098 B2 JPH0432098 B2 JP H0432098B2
- Authority
- JP
- Japan
- Prior art keywords
- weight
- block copolymer
- aromatic hydrocarbon
- vinyl aromatic
- polymer block
- 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 - Lifetime
Links
- 229920001400 block copolymer Polymers 0.000 claims description 82
- -1 vinyl aromatic hydrocarbon Chemical group 0.000 claims description 63
- 229920002554 vinyl polymer Polymers 0.000 claims description 61
- 229920000642 polymer Polymers 0.000 claims description 58
- 239000000203 mixture Substances 0.000 claims description 36
- 150000001993 dienes Chemical class 0.000 claims description 19
- 239000000463 material Substances 0.000 claims description 17
- 229920005989 resin Polymers 0.000 claims description 15
- 239000011347 resin Substances 0.000 claims description 15
- 229920006257 Heat-shrinkable film Polymers 0.000 claims description 6
- 229910052751 metal Inorganic materials 0.000 claims description 5
- 239000002184 metal Substances 0.000 claims description 5
- 150000004945 aromatic hydrocarbons Chemical class 0.000 claims description 4
- 239000011521 glass Substances 0.000 claims description 4
- 229910052573 porcelain Inorganic materials 0.000 claims description 4
- 125000000391 vinyl group Chemical group [H]C([*])=C([H])[H] 0.000 claims description 4
- 238000005452 bending Methods 0.000 claims description 3
- 239000000470 constituent Substances 0.000 claims description 3
- 229920001225 polyester resin Polymers 0.000 claims description 3
- 239000004645 polyester resin Substances 0.000 claims description 3
- 229920006122 polyamide resin Polymers 0.000 claims description 2
- 229920005668 polycarbonate resin Polymers 0.000 claims description 2
- 239000004431 polycarbonate resin Substances 0.000 claims description 2
- 229920005672 polyolefin resin Polymers 0.000 claims description 2
- 238000002372 labelling Methods 0.000 claims 1
- 229920000193 polymethacrylate Polymers 0.000 claims 1
- 238000000034 method Methods 0.000 description 23
- PPBRXRYQALVLMV-UHFFFAOYSA-N Styrene Natural products C=CC1=CC=CC=C1 PPBRXRYQALVLMV-UHFFFAOYSA-N 0.000 description 19
- 229920001577 copolymer Polymers 0.000 description 16
- 230000007613 environmental effect Effects 0.000 description 14
- 238000004806 packaging method and process Methods 0.000 description 10
- 238000002156 mixing Methods 0.000 description 7
- KAKZBPTYRLMSJV-UHFFFAOYSA-N Butadiene Chemical compound C=CC=C KAKZBPTYRLMSJV-UHFFFAOYSA-N 0.000 description 6
- RRHGJUQNOFWUDK-UHFFFAOYSA-N Isoprene Chemical compound CC(=C)C=C RRHGJUQNOFWUDK-UHFFFAOYSA-N 0.000 description 6
- 238000001125 extrusion Methods 0.000 description 6
- 229920003023 plastic Polymers 0.000 description 6
- 239000004033 plastic Substances 0.000 description 6
- 239000004793 Polystyrene Substances 0.000 description 5
- BZHJMEDXRYGGRV-UHFFFAOYSA-N Vinyl chloride Chemical compound ClC=C BZHJMEDXRYGGRV-UHFFFAOYSA-N 0.000 description 5
- 235000013305 food Nutrition 0.000 description 5
- 238000005227 gel permeation chromatography Methods 0.000 description 5
- 229920002223 polystyrene Polymers 0.000 description 5
- 239000000654 additive Substances 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 238000010438 heat treatment Methods 0.000 description 4
- 229930195733 hydrocarbon Natural products 0.000 description 4
- 239000000178 monomer Substances 0.000 description 4
- 230000008569 process Effects 0.000 description 4
- 239000004215 Carbon black (E152) Substances 0.000 description 3
- 238000011088 calibration curve Methods 0.000 description 3
- 235000014113 dietary fatty acids Nutrition 0.000 description 3
- 239000000194 fatty acid Substances 0.000 description 3
- 229930195729 fatty acid Natural products 0.000 description 3
- 150000002430 hydrocarbons Chemical class 0.000 description 3
- 238000004898 kneading Methods 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- VLKZOEOYAKHREP-UHFFFAOYSA-N n-Hexane Chemical compound CCCCCC VLKZOEOYAKHREP-UHFFFAOYSA-N 0.000 description 3
- 239000002904 solvent Substances 0.000 description 3
- 229920003048 styrene butadiene rubber Polymers 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- IANQTJSKSUMEQM-UHFFFAOYSA-N 1-benzofuran Chemical compound C1=CC=C2OC=CC2=C1 IANQTJSKSUMEQM-UHFFFAOYSA-N 0.000 description 2
- YBYIRNPNPLQARY-UHFFFAOYSA-N 1H-indene Chemical compound C1=CC=C2CC=CC2=C1 YBYIRNPNPLQARY-UHFFFAOYSA-N 0.000 description 2
- SDJHPPZKZZWAKF-UHFFFAOYSA-N 2,3-dimethylbuta-1,3-diene Chemical compound CC(=C)C(C)=C SDJHPPZKZZWAKF-UHFFFAOYSA-N 0.000 description 2
- PEDCQBHIVMGVHV-UHFFFAOYSA-N Glycerine Chemical compound OCC(O)CO PEDCQBHIVMGVHV-UHFFFAOYSA-N 0.000 description 2
- BAPJBEWLBFYGME-UHFFFAOYSA-N Methyl acrylate Chemical compound COC(=O)C=C BAPJBEWLBFYGME-UHFFFAOYSA-N 0.000 description 2
- MZRVEZGGRBJDDB-UHFFFAOYSA-N N-Butyllithium Chemical compound [Li]CCCC MZRVEZGGRBJDDB-UHFFFAOYSA-N 0.000 description 2
- YTPLMLYBLZKORZ-UHFFFAOYSA-N Thiophene Chemical compound C=1C=CSC=1 YTPLMLYBLZKORZ-UHFFFAOYSA-N 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 2
- XECAHXYUAAWDEL-UHFFFAOYSA-N acrylonitrile butadiene styrene Chemical compound C=CC=C.C=CC#N.C=CC1=CC=CC=C1 XECAHXYUAAWDEL-UHFFFAOYSA-N 0.000 description 2
- 229920000122 acrylonitrile butadiene styrene Polymers 0.000 description 2
- 239000004676 acrylonitrile butadiene styrene Substances 0.000 description 2
- 239000002216 antistatic agent Substances 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 238000009472 formulation Methods 0.000 description 2
- 230000026030 halogenation Effects 0.000 description 2
- 238000005658 halogenation reaction Methods 0.000 description 2
- 229920005669 high impact polystyrene Polymers 0.000 description 2
- 239000004797 high-impact polystyrene Substances 0.000 description 2
- 239000003999 initiator Substances 0.000 description 2
- 239000000314 lubricant Substances 0.000 description 2
- 150000002900 organolithium compounds Chemical class 0.000 description 2
- 238000012858 packaging process Methods 0.000 description 2
- 239000004014 plasticizer Substances 0.000 description 2
- 229920003217 poly(methylsilsesquioxane) Polymers 0.000 description 2
- 229920002285 poly(styrene-co-acrylonitrile) Polymers 0.000 description 2
- AHAREKHAZNPPMI-AATRIKPKSA-N (3e)-hexa-1,3-diene Chemical compound CC\C=C\C=C AHAREKHAZNPPMI-AATRIKPKSA-N 0.000 description 1
- PMJHHCWVYXUKFD-SNAWJCMRSA-N (E)-1,3-pentadiene Chemical compound C\C=C\C=C PMJHHCWVYXUKFD-SNAWJCMRSA-N 0.000 description 1
- YVLJEXBGMVDKBR-UHFFFAOYSA-N 1,10-dichloro-7-methyldec-1-ene Chemical compound ClCCCC(C)CCCCC=CCl YVLJEXBGMVDKBR-UHFFFAOYSA-N 0.000 description 1
- NVZWEEGUWXZOKI-UHFFFAOYSA-N 1-ethenyl-2-methylbenzene Chemical compound CC1=CC=CC=C1C=C NVZWEEGUWXZOKI-UHFFFAOYSA-N 0.000 description 1
- UVHXEHGUEKARKZ-UHFFFAOYSA-N 1-ethenylanthracene Chemical compound C1=CC=C2C=C3C(C=C)=CC=CC3=CC2=C1 UVHXEHGUEKARKZ-UHFFFAOYSA-N 0.000 description 1
- QEDJMOONZLUIMC-UHFFFAOYSA-N 1-tert-butyl-4-ethenylbenzene Chemical compound CC(C)(C)C1=CC=C(C=C)C=C1 QEDJMOONZLUIMC-UHFFFAOYSA-N 0.000 description 1
- IGGDKDTUCAWDAN-UHFFFAOYSA-N 1-vinylnaphthalene Chemical compound C1=CC=C2C(C=C)=CC=CC2=C1 IGGDKDTUCAWDAN-UHFFFAOYSA-N 0.000 description 1
- OEPOKWHJYJXUGD-UHFFFAOYSA-N 2-(3-phenylmethoxyphenyl)-1,3-thiazole-4-carbaldehyde Chemical compound O=CC1=CSC(C=2C=C(OCC=3C=CC=CC=3)C=CC=2)=N1 OEPOKWHJYJXUGD-UHFFFAOYSA-N 0.000 description 1
- KXGFMDJXCMQABM-UHFFFAOYSA-N 2-methoxy-6-methylphenol Chemical compound [CH]OC1=CC=CC([CH])=C1O KXGFMDJXCMQABM-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
- VXEGSRKPIUDPQT-UHFFFAOYSA-N 4-[4-(4-methoxyphenyl)piperazin-1-yl]aniline Chemical compound C1=CC(OC)=CC=C1N1CCN(C=2C=CC(N)=CC=2)CC1 VXEGSRKPIUDPQT-UHFFFAOYSA-N 0.000 description 1
- APMOEFCWQRJOPS-UHFFFAOYSA-N 5-ethenyl-1,5-dimethylcyclohexa-1,3-diene Chemical compound CC1=CC=CC(C)(C=C)C1 APMOEFCWQRJOPS-UHFFFAOYSA-N 0.000 description 1
- NLHHRLWOUZZQLW-UHFFFAOYSA-N Acrylonitrile Chemical compound C=CC#N NLHHRLWOUZZQLW-UHFFFAOYSA-N 0.000 description 1
- XDTMQSROBMDMFD-UHFFFAOYSA-N Cyclohexane Chemical compound C1CCCCC1 XDTMQSROBMDMFD-UHFFFAOYSA-N 0.000 description 1
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 1
- 239000004640 Melamine resin Substances 0.000 description 1
- 229920000877 Melamine resin Polymers 0.000 description 1
- CERQOIWHTDAKMF-UHFFFAOYSA-N Methacrylic acid Chemical compound CC(=C)C(O)=O CERQOIWHTDAKMF-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
- 229920002845 Poly(methacrylic acid) Polymers 0.000 description 1
- 239000004698 Polyethylene Substances 0.000 description 1
- 239000004743 Polypropylene Substances 0.000 description 1
- 229920001328 Polyvinylidene chloride Polymers 0.000 description 1
- HVUMOYIDDBPOLL-XWVZOOPGSA-N Sorbitan monostearate Chemical compound CCCCCCCCCCCCCCCCCC(=O)OC[C@@H](O)[C@H]1OC[C@H](O)[C@H]1O HVUMOYIDDBPOLL-XWVZOOPGSA-N 0.000 description 1
- 229910021627 Tin(IV) chloride Inorganic materials 0.000 description 1
- 229920001807 Urea-formaldehyde Polymers 0.000 description 1
- XTXRWKRVRITETP-UHFFFAOYSA-N Vinyl acetate Chemical compound CC(=O)OC=C XTXRWKRVRITETP-UHFFFAOYSA-N 0.000 description 1
- 239000006096 absorbing agent Substances 0.000 description 1
- NIXOWILDQLNWCW-UHFFFAOYSA-N acrylic acid group Chemical group C(C=C)(=O)O NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- XYLMUPLGERFSHI-UHFFFAOYSA-N alpha-Methylstyrene Chemical compound CC(=C)C1=CC=CC=C1 XYLMUPLGERFSHI-UHFFFAOYSA-N 0.000 description 1
- 125000003277 amino group Chemical group 0.000 description 1
- 238000010539 anionic addition polymerization reaction Methods 0.000 description 1
- 239000002981 blocking agent Substances 0.000 description 1
- 238000012661 block copolymerization Methods 0.000 description 1
- OCWYEMOEOGEQAN-UHFFFAOYSA-N bumetrizole Chemical compound CC(C)(C)C1=CC(C)=CC(N2N=C3C=C(Cl)C=CC3=N2)=C1O OCWYEMOEOGEQAN-UHFFFAOYSA-N 0.000 description 1
- 125000003178 carboxy group Chemical group [H]OC(*)=O 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 238000013329 compounding Methods 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 235000009508 confectionery Nutrition 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 239000007822 coupling agent Substances 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 230000002542 deteriorative effect Effects 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- MCPKSFINULVDNX-UHFFFAOYSA-N drometrizole Chemical compound CC1=CC=C(O)C(N2N=C3C=CC=CC3=N2)=C1 MCPKSFINULVDNX-UHFFFAOYSA-N 0.000 description 1
- 229920001971 elastomer Polymers 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000006735 epoxidation reaction Methods 0.000 description 1
- 239000003822 epoxy resin Substances 0.000 description 1
- 150000002148 esters Chemical class 0.000 description 1
- 150000004665 fatty acids Chemical class 0.000 description 1
- 235000013611 frozen food Nutrition 0.000 description 1
- 125000000524 functional group Chemical group 0.000 description 1
- 235000011187 glycerol Nutrition 0.000 description 1
- 229920001519 homopolymer Polymers 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 125000004435 hydrogen atom Chemical class [H]* 0.000 description 1
- IXCSERBJSXMMFS-UHFFFAOYSA-N hydrogen chloride Substances Cl.Cl IXCSERBJSXMMFS-UHFFFAOYSA-N 0.000 description 1
- 229910000041 hydrogen chloride Inorganic materials 0.000 description 1
- 238000005984 hydrogenation reaction Methods 0.000 description 1
- 125000002887 hydroxy group Chemical group [H]O* 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 229920005684 linear copolymer Polymers 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 125000005395 methacrylic acid group Chemical group 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- RKISUIUJZGSLEV-UHFFFAOYSA-N n-[2-(octadecanoylamino)ethyl]octadecanamide Chemical compound CCCCCCCCCCCCCCCCCC(=O)NCCNC(=O)CCCCCCCCCCCCCCCCC RKISUIUJZGSLEV-UHFFFAOYSA-N 0.000 description 1
- 125000002560 nitrile group Chemical group 0.000 description 1
- 239000003921 oil Substances 0.000 description 1
- 229910000489 osmium tetroxide Inorganic materials 0.000 description 1
- 239000012285 osmium tetroxide Substances 0.000 description 1
- 238000006864 oxidative decomposition reaction Methods 0.000 description 1
- 239000012785 packaging film Substances 0.000 description 1
- 229920006280 packaging film Polymers 0.000 description 1
- 239000005022 packaging material Substances 0.000 description 1
- 229920001568 phenolic resin Polymers 0.000 description 1
- 239000005011 phenolic resin Substances 0.000 description 1
- 229960000969 phenyl salicylate Drugs 0.000 description 1
- 239000000049 pigment Substances 0.000 description 1
- PMJHHCWVYXUKFD-UHFFFAOYSA-N piperylene Natural products CC=CC=C PMJHHCWVYXUKFD-UHFFFAOYSA-N 0.000 description 1
- 229920001083 polybutene Polymers 0.000 description 1
- 229920001707 polybutylene terephthalate Polymers 0.000 description 1
- 229920000647 polyepoxide Polymers 0.000 description 1
- 229920000573 polyethylene Polymers 0.000 description 1
- 229920000139 polyethylene terephthalate Polymers 0.000 description 1
- 239000005020 polyethylene terephthalate Substances 0.000 description 1
- 239000003505 polymerization initiator Substances 0.000 description 1
- 238000006116 polymerization reaction Methods 0.000 description 1
- 229920001155 polypropylene Polymers 0.000 description 1
- 239000004800 polyvinyl chloride Substances 0.000 description 1
- 229920000915 polyvinyl chloride Polymers 0.000 description 1
- 239000005033 polyvinylidene chloride Substances 0.000 description 1
- 238000007639 printing Methods 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 229920005604 random copolymer Polymers 0.000 description 1
- 239000005060 rubber Substances 0.000 description 1
- ZQBAKBUEJOMQEX-UHFFFAOYSA-N salicylic acid phenyl ester Natural products OC1=CC=CC=C1C(=O)OC1=CC=CC=C1 ZQBAKBUEJOMQEX-UHFFFAOYSA-N 0.000 description 1
- 239000005049 silicon tetrachloride Substances 0.000 description 1
- 229920002545 silicone oil Polymers 0.000 description 1
- 229920002050 silicone resin Polymers 0.000 description 1
- 235000011076 sorbitan monostearate Nutrition 0.000 description 1
- 239000001587 sorbitan monostearate Substances 0.000 description 1
- 229940035048 sorbitan monostearate Drugs 0.000 description 1
- 239000003381 stabilizer Substances 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 125000000542 sulfonic acid group Chemical group 0.000 description 1
- 150000003505 terpenes Chemical class 0.000 description 1
- 235000007586 terpenes Nutrition 0.000 description 1
- 125000003396 thiol group Chemical group [H]S* 0.000 description 1
- 229930192474 thiophene Natural products 0.000 description 1
- HPGGPRDJHPYFRM-UHFFFAOYSA-J tin(iv) chloride Chemical compound Cl[Sn](Cl)(Cl)Cl HPGGPRDJHPYFRM-UHFFFAOYSA-J 0.000 description 1
- 229920006337 unsaturated polyester resin Polymers 0.000 description 1
- 230000037303 wrinkles Effects 0.000 description 1
Landscapes
- Manufacture Of Macromolecular Shaped Articles (AREA)
- Shaping By String And By Release Of Stress In Plastics And The Like (AREA)
- Compositions Of Macromolecular Compounds (AREA)
Description
〔産業上の利用分野〕
本発明は、低温収縮性、耐衝撃性及び耐環境破
壊性に優れたブロツク共重合体混合物の熱収縮性
フイルム、シート、チユーブ等の成形品に関す
る。
〔従来の技術〕
収縮包装はこれまでの包装技術では避けられな
かつたダブツキやシワがきれいに解決でき、又商
品に密着した包装や異形物の包装が迅速にできる
ことから最近特に食品包装用にその利用が増加し
ている。従来、収縮包装用フイルム、シート等の
素材としては、低温収縮性、透明性、機械的強度
等の要求特性を満足することから塩化ビニル樹脂
が主に使用されている。しかし塩化ビニル樹脂は
塩化ビニルモノマーや可塑剤類の衛生上の問題、
償却時の塩化水素の発生問題等からその代替品が
強く要望されている。
一方、ビニル芳香族炭化水素と共役ジエンから
成るブロツク共重合体樹脂は上記の様な諸問題を
有せず、しかも良好な透明性と耐衝撃性を有する
ことから食品包装容器の素材として広く利用され
つつある。しかしながら、従来知られているブロ
ツク共重合体は延伸温度が高く、又収縮を起す温
度も高いため熱収縮包装用素材としては不適当で
あつた。
例えば特開昭49−10249号公報及び特開昭49−
108177号公報にはそれぞれスチレン系炭化水素含
有量50〜95重量%のブロツク共重合体及び該ブロ
ツク共重合体にスチレン系樹脂を配合した組成物
を2軸延伸した包装用フイルムが記載されている
が、かかるフイルムは熱収縮温度が約100℃以上
でなければ十分な収縮率は得られない。
かかるブロツク共重合体の低温収縮性を改良す
る方法も特開昭50−6673号公報や特開昭55−5544
号公報で試みられている。前者の方法は線状共重
合体にチユーブラ法を適用することによつて有効
な高度の配向が起こる様な温度域で膨張延伸して
同時2軸配向を行い、良好な低温熱収縮性を持つ
フイルムを製造する方法である。しかしながら、
この方法においては原料樹脂のブタジエン含有量
の多寡に応じて極めて限選された温度範囲で膨張
延伸を開始し、しかも膨張開始点から膨張終了点
に至る延伸帯域のフイルムに厳密にコントロール
された温度勾配をつけなれけば所望の低温熱収縮
性を持つフイルムが得られず、従つて容易に実施
し難いという欠点を有する。又、後者の方法はス
チレン含有量が65〜90%のスチレン・ブタジエン
ブロツク共重合体にスチレン含有量が20〜50%の
スチレン・ブタジエンブロツク共重合体を10〜30
重量%配合することにより低温収縮性の2軸延伸
フイルムを製造する方法であるが、この方法は両
者の混練状態が不良の場合、充分な低温収縮性が
発現できず、混練方法に高度のテクニツクを要し
て容易に実施し難いという欠点を有する。
〔発明が解決しようとする課題〕
本発明者らはかかる現状に鑑み、低温収縮性の
優れたブロツク共重合体フイルム、シート等を容
易に得る方法について鋭意検討を進めた結果、ブ
ロツク共重合体を構成するビニル芳香族炭化水素
重合体ブロツクがある特定の範囲の分子量を有す
るブロツク共重合体或いはこの様なブロツク共重
合体に低分子量ビニル芳香族炭化水素重合体や通
常の高分子量ビニル芳香族炭化水素重合体を配合
した組成物が比較的低温で延伸でき、その目的が
達成されることを見い出し、特願昭56−22989号、
特願昭56−63325号及び特願昭56−95314号を出願
した。その後、本発明者らはその改良について更
に検討を進めた結果、特定のブロツク共重合体を
数種組合せることにより低温収縮性のみならず耐
衝撃性及び耐環境破壊性に優れた熱収縮性の成形
品が得られることを新たに見い出し、本発明を完
成するに至つた。
〔課題を解決するための手段〕
即ち、本発明は、
(A) 少なくとも1個のビニル芳香族炭化水素を主
体とする重合体ブロツクと少なくとも1個の共
役ジエンを主体とする重合体ブロツクを有し、
ビニル芳香族炭化水素含有量が75〜95重量%で
あるブロツク共重合体であり、しかも該ブロツ
ク共重合体の数平均分子量が100000〜350000、
該ブロツク共重合体中に組込まれているビニル
芳香族炭化水素重合体ブロツクの数平均分子量
が10000〜100000であるブロツク共重合体、30
〜95重量部、
(B) 少なくとも1個のビニル芳香族炭化水素を主
体とする重合体ブロツクと少なくとも1個の共
役ジエンを主体とする重合体ブロツクを有し、
ビニル芳香族炭化水素含有量が50重量%を超
え、75重量%未満であるブロツク共重合体、70
〜5重量部
(C) 少なくとも1個のビニル芳香族炭化水素を主
体とする重合体ブロツクと少なくとも1個の共
役ジエンを主体とする重合体ブロツクを有し、
ビニル芳香族炭化水素含有量が10〜50重量%で
あるブロツク共重合体を前記成分(A)と成分(B)の
合計量100重量部に対して5重量部以上60重量
部以下、
からなり、その曲げ弾性率が7000〜18000Kg/cm2
であるブロツク共重合体混合物を延伸し、延伸方
向における90℃の熱収縮率が10%以上である熱収
縮性成形品に関する。
本発明において熱収縮性成形品とは、加熱によ
り収縮する特性を有するフイルム、シート或いは
チユーブ状の成形品を云う。
本発明の熱収縮性成形品は低温において優れた
収縮性を有するため、収縮包装工程において高温
で長時間加熱すると変質や変形を生じる様な物品
の包装、例えば生鮮食料品やプラスチツク成形品
等の包装に適する。又、本発明の熱収縮性成形品
は耐環境破壊性に優れ、本発明の熱収縮性成形品
で被覆した物品を気温や温度変化の激しい屋外環
境下に放置しても破壊しにくいという特長を有す
る。特に、被覆される物品が金属、磁器、ガラ
ス、ポリエステル系樹脂などのように特性、例え
ば熱膨張率や吸水性などが極めて異なる材質で構
成されている場合には、従来の熱収縮性成形品で
は被覆後の耐環境破壊性が劣り、容易にクラツク
が入るという欠点を有していたが、本発明の熱収
縮性成形品を用いた場合にはこの様な問題がな
く、長期の自然環境下における放置に耐える。従
つて本発明の熱収縮性成形品はかかる利点を生か
して、上記の様な材質で構成される容器類のラベ
ルなどの用途にとりわけ好適に利用できる。
以下、本発明を詳細に説明する。
本発明で使用する成分(A)、成分(B)或いは成分(C)
のブロツク共重合体は、いずれも、少なくとも1
個、好ましくは2個以上のビニル芳香族炭化水素
を主体とする重合体ブロツクと少なくとも1個の
共役ジエンを主体とする重合体ブロツクとを有す
るブロツク共重合体である。ここでビニル芳香族
炭化水素を主体とする重合体ブロツクとはビニル
芳香族炭化水素含有量が50重量%を超える、好ま
しくは70重量%以上の重合体ブロツクである。ま
た、共役ジエンを主体とする重合体ブロツクと
は、共役ジエンの含有量が50重量%以上、好まし
くは70重量%以上、更に好ましくは90重量%以上
の重合体ブロツクである。ビニル芳香族炭化水素
を主体とする重合体ブロツク或いは共役ジエンを
主体とする重合体ブロツク中にビニル芳香族炭化
水素と共役ジエンのランダム共重合体部分が存在
する場合、共重合されているビニル芳香族炭化水
素は重合体ブロツク中に均一に分布していても、
またテーパー(漸減)状に分布していてもよい。
本発明で使用するブロツク共重合体は基本的に
は従来公知の手法で製造でき、例えば特公昭36−
19286号公報、特公昭43−14979号公報、特公昭49
−36957号公報、特公昭48−2423号公報、特公昭
48−4106号公報などに記載された手法があげられ
るが、各構成ポリマーは後述する要件を満足する
様に製造条件を設定しなければならない。
上記の公知の手法はすべて、炭化水素溶剤中で
有機リチウム化合物等のアニオン重合開始剤を用
い、共役ジエンとビニル芳香族炭化水素をブロツ
ク共重合する手法である。
本発明においては、ポリマー構造が一般式、
(イ) (A−B)o
(ロ) A(―B−A)o
(ハ) B(―A−B)o
(上式において、Aはビニル芳香族炭化水素を主
体とする重合体ブロツクであり、Bは共役ジエン
を主体とする重合体ブロツクである。Aブロツク
とBブロツクとの境界は必ずしも明瞭に区別され
る必要はない。nは1以上の整数である。)
で表わされる線状ブロツク共重合体、あるいは一
般式、
(ニ) 〔(B−A)o――〕n+2―――X
(ホ) 〔(A−B)o――〕n+2―――X
(ヘ) 〔(B−A)o――Bn+2―――X
(ト) 〔(A−B)o――An+2―――X
(上式において、A、Bは前記と同じであり、X
は例えば四塩化ケイ素、四塩化スズなどのカツプ
リング剤の残基または多官能有機リチウム化合物
等の開始剤を残基を示す。m及びnは1以上の整
数である。)
で表わされるラジアルブロツク共重合体、あるい
はこれらのブロツク共重合体の任意のポリマー構
造の混合物が使用できる。
本発明において、ビニル芳香族炭化水素として
はスチレン、o−メチルスチレン、p−メチルス
チレン、p−tert−ブチルスチレン、1,3−ジ
メチルスチレン、α−メチルスチレン、ビニルナ
フタレン、ビニルアントラセンなどがあるが、特
に一般的なものとしてはスチレンが挙げられる。
これらは1種のみならず2種以上混合して使用し
てもよい。共役ジエンとしは、1対の共役二重結
合を有するジオレフインであり、たとえば1,3
−ブタジエン、2−メチル−1,3−ブタジエン
(イソプレン)、2,3−ジメチル−1,3−ブタ
ジエン、1,3−ペンタジエン、1,3−ヘキサ
ジエンなどであるが、特に一般的なものとしては
1,3−ブタジエン、イソプレンが挙げられる。
これらは1種のみならず2種以上混合して使用し
てもよい。
本発明で使用する成分(A)のブロツク共重合体
は、該ブロツク共重合体の数平均分子量が100000
〜350000、好ましくは130000〜300000で、ブロツ
ク共重合体中に組込まれているビニル芳香族炭化
水素重合体ブロツクの数平均分子量が10000〜
100000、好ましくは15000〜70000であり、しかも
ビニル芳香族炭化水素含有量が75〜95重量%、好
ましくは77〜90重量%であるブロツク共重合体で
ある。ブロツク共重合体(A)の数平均分子量が
100000未満の場合には耐環境破壊性能が劣り、数
平均分子量が350000を超える場合は他成分との混
合性及びブロツク共重合体混合物の加工性が劣る
ため好ましくない。又、ブロツク共重合体中に組
込まれているビニル芳香族炭化水素重合体ブロツ
クの数平均分子量が10000未満の場合には引張強
度や剛性が劣り、又100000を超える場合は低温延
伸性や低温収縮性が劣るため好ましくない。更に
ビニル芳香族炭化水素含有量が75重量%未満の場
合は引張強度や剛性が劣り、又95重量%を超える
場合は耐衝撃性が劣るため好ましくない。
尚、本発明においてブロツク共重合体の数平均
分子量とは、ゲルパーミエーシヨンクロマトグラ
フイー(以下GPCという)用の単分散ポリスチ
レンのGPCにより、そのピークカウント数と単
分散ポリスチレンの数平均分子量との検量線を作
成し、ブロツク共重合体のGPCパターンの主ピ
ークカウント数に対応する数平均分子量を検量線
から読みとつた値を云う。又、ブロツク共重合体
中に組込まれているビニル芳香族炭化水素重合体
ブロツクの数平均分子量とは、四酸化オスミウム
を触媒としてジ・ターシヤリーブチルハイドロパ
ーオキサイドによりブロツク共重合体を酸化分解
する方法(例えば、L.M.KOLTHOFF、etal.、
J.Polym.Sci.1429(1946)に記載の方法)により
得たビニル芳香族炭化水素重合体ブロツク成分
(但し平均重合度が約30〜50以下のビニル芳香族
炭化水素重合体ブロツク成分は除く)の数平均分
子量を、GCP用の単分散ポリスチレンを用いて
作成した検量線を移用し、常法(例えば「ゲルク
ロマトグラフイ<基礎編>講談社発行)に従つて
算出した値を言う。
次に、本発明で使用する成分(B)のブロツク共重
合体は、ビニル芳香族炭化水素含有量が50重量%
を超え、75重量%未満、好ましくは60〜73重量%
である。ビニル芳香族炭化水素含有量が50重量%
以下の場合は成分(A)との相溶性が十分でなく耐環
境破壊性能が劣り、又75重量%以上では耐環境破
壊性能が悪化する。本発明においては、耐環境破
壊性能の向上という点で、ブロツク共重合体(B)の
数平均分子量は80000〜250000、好ましくは
100000〜200000のブロツク共重合体を使用するの
が好ましい。成分(B)のブロツク共重合体中に組込
まれているビニル芳香族炭化水素重合体ブロツク
の数平均分子量は特に制限はないが、より低温収
縮性の良好な成形品を得る上で該ブロツクの数平
均分子量が10000〜100000、好ましくは15000〜
70000のブロツク共重合体を用いることが推奨さ
れる。
本発明においては、成分(A)と成分(B)のブロツク
共重合体混合物に、成分(C)としてビニル芳香族炭
化水素含有量が10〜50重量%、好ましくは15〜45
重量%のブロツク共重合体を配合して使用するこ
とにより低温収縮性、耐環境破壊性を悪化するこ
となく耐衝撃性を更に向上させることができる。
成分(C)としては、ブロツク共重合体の数平均分子
量が20000〜250000、好ましくは40000〜200000の
ものが一般に使用できる。
本発明において、成分(A)と成分(B)の重量比は
30:70〜95:5、好ましくは50:50〜90:10であ
る。各成分の配合量がこの範囲外である場合には
耐環境破壊性が劣るため好ましくない。又成分(C)
の配合量は、成分(A)と成分(B)の合計量100重量部
に対して5重量部以上60重量部以下、好ましくは
5重量部以上50重量部以下である。成分(C)の配合
量が60重量部を超える場合は、引張強度や剛性が
劣るため好ましくない。
本発明において、成分(A)と成分(B)及び成分(C)か
らなるブロツク共重合体混合物は、その曲げ弾性
率が7000〜18000Kg/cm2、好ましくは9000〜16000
Kg/cm2である。曲げ弾性率が7000Kg/cm2未満の場
合は剛性が劣り、本発明の熱収縮性成形品、例え
ばフイルム、チユーブ等を収縮包装用素材として
使用する場合に包装工程においてヘタリを生じて
正常な包装ができにくいという問題を生じる。
又、曲げ弾性率が18000を超える場合は耐環境破
壊性が劣るため好ましくない。尚、本発明におい
て曲げ弾性率とは、成分(A)と成分(B)及び成分(C)か
らなるブロツク共重合体混合物の曲げ弾性率を
JIS−K−7203に基づいて測定した値を云う。
本発明において特に好適なブロツク共重合体混
合物は、ビニル芳香族炭化水素含有量が77〜90重
量%、ブロツク共重合体の数平均分子量が130000
〜300000、ブロツク共重合体中に組込まれている
ビニル芳香族炭化水素重合体ブロツクの数平均分
子量が15000〜70000であるブロツク共重合体を成
分(A)とし、ビニル芳香族炭化水素含有量が60〜73
重量%、ブロツク共重合体の数平均分子量が
100000〜200000、ブロツク共重合体中に組込まれ
ているビニル芳香族炭化水素重合体ブロツクの数
平均分子量が15000〜70000であるブロツク共重合
体を成分(B)とするブロツク共重合体混合物に更に
成分(C)としてビニル芳香族炭化水素含有量が15〜
45重量%、ブロツク共重合体の数平均分子量が
40000〜200000のブロツク共重合体を配合したブ
ロツク共重合体混合物である。これらを用いた熱
収縮性成形品は特に低温収縮性に優れ、延伸方向
における80℃の熱収縮率が15%以上という収縮性
能を有する。尚、上記の好適な実施態様におい
て、ブロツク共重合体中に組込まれているビニル
芳香族炭化水素重合体ブロツクの重量平均分子量
と数平均分子量の比(/n)は、熱収縮性を
更に向上させるという点において1.25未満のもの
が推奨される。
本発明で使用するブロツク共重合体は、その基
本的な特性、例えば低温収縮性、剛性等を損わな
い範囲内で水素添加、ハロゲン化、ハロゲン化水
素化、エポキシ化、或いは化学反応により水酸
基、チオール基、ニトリル基、スルホン酸基、カ
ルボキシル基、アミノ基等の官能基の導入を行う
などの改質が行われていてもよい。
本発明では、ブロツク共重合体混合物(成分(a)
とする)に、低温延伸性及び低温収縮性を改良す
る目的で低分子量ビニル芳香族炭化水素重合体又
は共重合体(成分(b)とする)を配合してもよい。
また、低温延伸性、低温収縮性及び剛性を更に
改良する目的でブロツク共重合体に前記成分(b)と
比較的分子量の高いビニル芳香族炭化水素重合体
又は共重合体(成分(c)とする)を配合してもよ
い。更に、剛性を改良する目的でブロツク共重合
体に成分(c)のみを配合してもよい。
本発明で使用する成分(b)及び(c)のビニル芳香族
炭化水素重合体または共重合体は、前記のビニル
芳香族炭化水素系モノマーの単独重合体または共
重合体の他、前記のビニル芳香族炭化水素系モノ
マーと他のビニルモノマー、例えばエチレン、プ
ロピレン、ブチレン、塩化ビニル、塩化ビニリデ
ン、酢酸ビニル、アクリル酸メチル等のアクリル
酸エステル、メタクリル酸メチル等のメタクリル
酸エステル、アクリロニトリル等との共重合体が
含まれる。特に好ましいのは、スチレンの単独重
合体、スチレンとα−メチルスチレンの共重合
体、スチレンとメタクリル酸メチルの共重合体で
ある。
本発明で使用する成分(b)の低分子量ビニル芳香
族炭化水素重合体または共重合体の数平均分子量
は、20000以下、好ましくは200〜10000、更に好
ましくは300〜5000である。数平均分子量が20000
を超えると低温収縮性の改良効果がなくなるため
好ましくない。特に好ましいのは、数平均分子量
が300以上、500未満のものであり、かかる低分子
量の重合体または共重合体は低温収縮性の改良効
果が極めて良好である。成分(b)の低分子量ビニル
芳香族炭化水素重合体または共重合体の配合量
は、成分(a)のブロツク共重合体100重量部に対し
て、5〜100重量部、好ましくは10〜70重量部、
更に好ましくは15〜55重量部である。
本発明で成分(c)として使用する比較的分子量の
高いビニル芳香族炭化水素重合体または共重合体
の数平均分子量は、30000以上、好ましくは50000
〜1000000、更に好ましくは80000〜500000であ
る。成分(c)の数平均分子量が30000未満の場合に
は、剛性の改良効果が十分でないため好ましくな
い。成分(c)のビニル芳香族炭化水素重合体または
共重合体の配合量は、成分(a)のブロツク共重合体
混合物100重量部に対して、5〜80重量部、好ま
しくは10〜60重量部、更に好ましくは15〜45重量
部である。
本発明で使用するブロツク共重合体混合物又は
上記の如きビニル芳香族炭化水素重合体又は共重
合体を配合したブロツク共重合体組成物には目的
に応じて種々の添加剤を添加することができる。
好適な添加剤としては30重量部以下のクマロン−
インデン樹脂、テルペン樹脂、オイル等の軟化
剤、可塑剤があげられる。また、各種の安定剤、
顔料、ブロツキング防止剤、帯電防止剤、滑剤等
も添加できる。尚、ブロツキング防止剤、滑剤、
帯電防止剤としては、例えば脂肪酸アマイド、エ
チレンビスステアロアミド、ソルビタンモノステ
アレート、脂肪酸アルコールの飽和脂肪酸エステ
ル、ペンタエリストール脂肪酸エステル等、又紫
外線吸収剤としては、p−t−ブチルフエニルサ
リシレート、2−(2′−ヒドロキシ−5′−メチル
フエニル)ベンゾトリアゾール、2−(2′−ヒド
ロキシ−3′−t−ブチル−5′−メチルフエニル)
−5−クロロベンゾトリアゾール、2,5−ビス
−〔5′−t−ブチルベンゾキサゾリル−(2)〕チオ
フエン等、「プラスチツクおよびゴム用添加剤実
用便覧」(化学工業社」に記載された化合物類が
使用できる。これらは一般に0.01〜5重量%、好
ましくは0.1〜2重量%の範囲で用いられる。
本発明において成分(A)と成分(B)と成分(C)のブロ
ツク共重合体混合物と他の添加剤を混合する方法
は、従来公知のあらゆる配合方法によつて製造す
ることができる。例えば、オープンロール、イン
テンシブミキサー、インターナルミキサー、コニ
ーダー、二軸ローター付の連続混練機、押出機等
の一般的な混和機を用いた溶融混練方法、各成分
を溶剤に溶解または分散混合後溶剤を加熱除去す
る方法等が用いられる。
前記のブロツク共重合体混合物又はブロツク共
重合体組成物から熱収縮性の成形品を得るには、
従来塩化ビニル樹脂等のフイルム等に対し熱収縮
性を対与するために採られている手法が基本的に
は利用できるが、得られた熱収縮性成形品は90℃
における熱収縮率が10%以上、好ましくは15〜99
%、更に好ましくは20〜80%でなければならな
い。90℃における熱収縮率が10%未満の場合は低
温収縮性が悪いため収縮包装工程において該工程
を高温かつ均一に調整したり、長時間加熱する必
要があり、高温で変質や変形を生じる様な物品の
包装が不可能となつたり収縮包装処理能力が低下
するため好ましくない。尚、本発明において90℃
における熱収縮率とは、1軸延伸又は2軸延伸し
た成形品を90℃の熱水、シリコーンオイル、グリ
セリン等の成形品の特性を阻害しない熱媒体中に
5分間浸漬したときの成形品の各延伸方向におけ
る熱収縮率である。
前記のブロツク共重合体混合物又はブロツク共
重合体組成物から熱収縮性の1軸または2軸延伸
成形品を得るには、ブロツク共重合体混合物又は
ブロツク共重合体組成物を通常のTダイまたは環
状ダイからフラツト状またはチユーブ状に150〜
250℃、好ましくは170〜220℃で押出成形し、得
られた未延伸物を1軸延伸または2軸延伸する。
例えば1軸延伸の場合、フイルム、シート状の場
合はカレンダーロール等で押出方向に、或いはテ
ンター等で押出方向と直交する方向に延伸し、チ
ユーブ状の場合はチユーブの押出方向または円周
方向に延伸する。2軸延伸の場合、フイルム、シ
ート状の場合には押出フイルムまたはシートを金
属ロール等で縦方向に延伸した後、テンター等で
横方向に延伸し、チユーブ状の納場合にはチユー
ブの押出方向及びチユーブの円周方向、即ちチユ
ーブ軸と直角をなす方向にそれぞれ同時に、ある
いは別々に延伸する。
この様にして得られる本発明の熱収縮性成形品
のうち熱収縮性フイルム又はチユーブは、一般に
厚さが5〜500μ、好ましくは10〜200μ、更に好
ましくは30〜100μの範囲になるように調整され
る。
本発明においては、延伸温度60〜120℃、好ま
しくは80〜110℃で、縦方向及び/または横方向
に延伸倍率1.5〜8倍、好ましくは2〜6倍に延
伸するのが好ましい。延伸温度が60℃未満の場合
には延伸時に破断を生じて所望の熱収縮性成形品
が得にくく、120℃を超える場合は低温収縮性の
良好なものが得難い。延伸倍率は用途によつて必
要とする収縮率を対応するように上記範囲内で選
定されるが、延伸倍率が1.5倍未満の場合は熱収
縮率が小さく熱収縮性包装用として好ましくな
く、又8倍を超える延伸倍率は延伸加工工程にお
ける安定生産上好ましくない。2軸延伸の場合、
縦方向及び横方向における延伸倍率は同一であつ
ても、異つていてもよい。1軸延伸後、または2
軸延伸後の熱収縮性成形品は、次いで必要に応じ
て冷却後直ちに60〜105℃、好ましくは80〜95℃
で短時間、例えば3〜60秒間、好ましくは10〜40
秒間熱処理して室温下における自然収縮を防止す
る手段を実施することも可能である。
本発明の1軸延伸または2軸延伸した成形品を
熱収縮性包装材として使用する場合、目的の熱収
縮率を達成するために150〜300℃、好ましくは
180〜250℃の温度で数秒から数分、好ましくは1
〜60秒、更に好ましくは2〜30秒加熱して熱収縮
させることができる。
本発明の1軸延伸または2軸延伸した成形品
は、従来の塩化ビニル樹脂系のものに比べ衛生上
優れたものであり、その特性を生かして種々の用
途、例えば生鮮食品、冷凍食品、菓子類の包装、
衣類、文具、玩具等の包装などに利用できる。特
に好ましい用途としては、本発明で規定するブロ
ツク共重合体混合物又はブロツク共重合体組成物
の1軸延伸フイルムに文字や図案を印刷した後、
プラスチツク成形品や金属製品、ガラス容器、磁
器等の被包装体表面に熱収縮により密着させて使
用する、いわゆる熱収縮性ラベル用素材としての
利用があげられる。とりわけ、本発明の1軸延伸
した熱収縮性のブロツク共重合体混合物又は組成
物のフイルムは低温収縮性、耐衝撃性及び耐環境
破壊性に優れるため、高温に加熱すると変形を生
ずる様なプラスチツク成形品の熱収縮性ラベル素
材の他、熱膨張率や吸水性などが本発明の熱収縮
性成形品とは極めて異なる材質、例えば金属、磁
器、ガラス、ポリエチレン、ポリプロピレン、ポ
リブテンなどのポリオレフイン系樹脂、ポリメタ
クリル酸エステル系樹脂、ポリカーボネート系樹
脂、ポリエチレンテレフタレート、ポリブチレン
テレフタレートなどのポリエステル系樹脂、ポリ
アミド系樹脂から選ばれる少なくとも1種を構成
素材として用いた容器の熱収縮性ラベル素材とし
て好適に利用できる。
尚、本発明の熱収縮性成形品が適用できるプラ
スチツク容器を構成する材質としては、上記の樹
脂類の他、ポリスチレン、ゴム変性耐衝撃性ポリ
スチレン(HIPS)、スチレン−アクリロニトリ
ル共重合体、スチレン−無水マレイン酸共重合
体、アクリロニトリル−ブタジエン−スチレン共
重合体(ABS)、メタクリル酸エステル−ブタジ
エン−スチレン共重合体(MBS)、ポリ塩化ビニ
ル系樹脂、ポリ塩化ビニリデン系樹脂、フエノー
ル樹脂、ユリア樹脂、メラミン樹脂、エポキシ樹
脂、不飽和ポリエステル樹脂、シリコーン樹脂な
どを挙げることができる。これらプラスチツク容
器は2種以上の樹脂類の混合物でも、積層体であ
つてもよい。
尚、本発明で規定するブロツク共重合体混合物
を1軸延伸して得た熱収縮性のフイルムを熱収縮
性ラベル用素材として使用する場合、延伸方向と
直交する方向における90℃の熱収縮率は10%未
満、好ましくは5%以下、更に好ましくは3%以
下であることが好ましい。
本発明を更に詳細に説明するために以下に本発
明の実施例を示すが、本発明の内容をこれらの実
施例に限定するものでないことは云うまでもな
い。
以下の実施例においては、ポリマー構造、スチ
レン含有量、ブロツク共重合体の数平均分子量及
びポリスチレンブロツクの数平均分子量が第1表
に示したようなスチレン−ブタジエンブロツク共
重合体をシクロヘキサン又はn−ヘキサン中でn
−ブチルリチウムを開始剤として重合したものを
用いた。
[Industrial Field of Application] The present invention relates to molded products such as heat-shrinkable films, sheets, tubes, etc. made of block copolymer mixtures having excellent low-temperature shrinkability, impact resistance, and environmental damage resistance. [Conventional technology] Shrink wrapping has recently been used particularly for food packaging because it can neatly eliminate the bagging and wrinkles that were unavoidable with conventional packaging techniques, and it can also quickly wrap products tightly or irregularly shaped items. is increasing. Conventionally, vinyl chloride resin has been mainly used as a material for shrink wrapping films, sheets, etc. because it satisfies required properties such as low-temperature shrinkability, transparency, and mechanical strength. However, vinyl chloride resin has hygienic problems due to vinyl chloride monomer and plasticizers.
There is a strong demand for a replacement product due to the problem of hydrogen chloride generation during depreciation. On the other hand, block copolymer resins made of vinyl aromatic hydrocarbons and conjugated dienes do not have the above problems and have good transparency and impact resistance, so they are widely used as materials for food packaging containers. It is being done. However, conventionally known block copolymers are unsuitable as materials for heat-shrinkable packaging because of their high stretching temperatures and high shrinkage temperatures. For example, JP-A-49-10249 and JP-A-49-
Publication No. 108177 describes a packaging film obtained by biaxially stretching a block copolymer having a styrene hydrocarbon content of 50 to 95% by weight, and a composition in which the block copolymer is blended with a styrene resin. However, such a film cannot achieve sufficient shrinkage unless the heat shrinkage temperature is about 100°C or higher. Methods for improving the low-temperature shrinkability of such block copolymers are also disclosed in JP-A-50-6673 and JP-A-55-5544.
This is attempted in the Publication No. In the former method, by applying the tubular method to a linear copolymer, simultaneous biaxial orientation is achieved through expansion stretching in a temperature range where effective high degree of orientation occurs, resulting in good low-temperature heat shrinkability. This is a method of manufacturing film. however,
In this method, expansion and stretching is started in a very limited temperature range depending on the butadiene content of the raw resin, and the temperature in the stretching zone from the expansion start point to the expansion end point is strictly controlled. If the slope is not adjusted properly, a film having the desired low-temperature heat shrinkability cannot be obtained, and therefore, it is difficult to carry out the process easily. In the latter method, a styrene-butadiene block copolymer with a styrene content of 20-50% is added to a styrene-butadiene block copolymer with a styrene content of 65-90%.
This method produces a biaxially stretched film with low-temperature shrinkability by blending the two by weight; however, if the kneading conditions of both components are poor, sufficient low-temperature shrinkability cannot be achieved, and the kneading method requires advanced techniques. This method has the disadvantage that it requires a lot of time and is difficult to implement. [Problems to be Solved by the Invention] In view of the current situation, the present inventors have carried out extensive studies on a method for easily obtaining block copolymer films, sheets, etc. with excellent low-temperature shrinkability. The vinyl aromatic hydrocarbon polymer block constituting the block is a block copolymer having a molecular weight within a certain range, or such a block copolymer is combined with a low molecular weight vinyl aromatic hydrocarbon polymer or a normal high molecular weight vinyl aromatic polymer. It was discovered that a composition containing a hydrocarbon polymer could be stretched at a relatively low temperature, and the purpose was achieved, and Japanese Patent Application No. 56-22989,
Applications were filed for Japanese Patent Application No. 56-63325 and Japanese Patent Application No. 56-95314. After that, the present inventors further investigated the improvement, and found that by combining several types of specific block copolymers, the product had not only low-temperature shrinkability but also heat-shrinkability with excellent impact resistance and environmental damage resistance. The inventors have newly discovered that it is possible to obtain a molded article, and have completed the present invention. [Means for Solving the Problems] That is, the present invention has (A) a polymer block mainly composed of at least one vinyl aromatic hydrocarbon and a polymer block mainly composed of at least one conjugated diene. death,
A block copolymer having a vinyl aromatic hydrocarbon content of 75 to 95% by weight, and a number average molecular weight of the block copolymer of 100,000 to 350,000,
A block copolymer in which the vinyl aromatic hydrocarbon polymer block incorporated into the block copolymer has a number average molecular weight of 10,000 to 100,000, 30
~95 parts by weight, (B) having at least one vinyl aromatic hydrocarbon-based polymer block and at least one conjugated diene-based polymer block;
Block copolymer with a vinyl aromatic hydrocarbon content of more than 50% and less than 75% by weight, 70
~5 parts by weight (C) having at least one polymer block mainly composed of vinyl aromatic hydrocarbon and at least one polymer block mainly composed of conjugated diene,
Consisting of 5 parts by weight or more and 60 parts by weight or less of a block copolymer having a vinyl aromatic hydrocarbon content of 10 to 50% by weight, based on 100 parts by weight of the total amount of component (A) and component (B). , its bending modulus is 7000~18000Kg/ cm2
This invention relates to a heat-shrinkable molded product obtained by stretching a block copolymer mixture having a heat shrinkage rate of 10% or more at 90°C in the stretching direction. In the present invention, a heat-shrinkable molded article refers to a film, sheet, or tube-shaped molded article that has the property of shrinking when heated. Since the heat-shrinkable molded product of the present invention has excellent shrinkability at low temperatures, it can be used to package items that would deteriorate or deform if heated at high temperatures for a long period of time during the shrink-wrapping process, such as fresh foods and plastic molded products. Suitable for packaging. In addition, the heat-shrinkable molded product of the present invention has excellent environmental damage resistance, and has the feature that it is difficult to break even if an article coated with the heat-shrinkable molded product of the present invention is left in an outdoor environment with severe temperature changes. has. In particular, when the article to be coated is made of materials such as metal, porcelain, glass, or polyester resin, which have very different properties such as coefficient of thermal expansion and water absorption, conventional heat-shrinkable molded products However, when using the heat-shrinkable molded product of the present invention, there is no such problem and it can withstand long-term environmental damage. It can withstand being left in the ground. Therefore, by taking advantage of these advantages, the heat-shrinkable molded article of the present invention can be particularly suitably used for applications such as labels for containers made of the above-mentioned materials. The present invention will be explained in detail below. Component (A), component (B) or component (C) used in the present invention
Each of the block copolymers has at least one
It is a block copolymer having one, preferably two or more, vinyl aromatic hydrocarbon-based polymer blocks and at least one conjugated diene-based polymer block. Here, the polymer block mainly composed of vinyl aromatic hydrocarbons is a polymer block in which the vinyl aromatic hydrocarbon content exceeds 50% by weight, preferably 70% by weight or more. Furthermore, a polymer block mainly composed of conjugated diene is a polymer block in which the content of conjugated diene is 50% by weight or more, preferably 70% by weight or more, and more preferably 90% by weight or more. When a random copolymer portion of a vinyl aromatic hydrocarbon and a conjugated diene is present in a polymer block mainly composed of vinyl aromatic hydrocarbons or a polymer block mainly composed of conjugated dienes, the copolymerized vinyl aromatic Although the group hydrocarbons are uniformly distributed in the polymer block,
Alternatively, the distribution may be tapered (gradually decreasing). The block copolymer used in the present invention can basically be produced by conventionally known methods.
Publication No. 19286, Special Publication No. 14979, Publication No. 14979, Special Publication No. 14979
-36957 Publication, Special Publication No. 48-2423, Special Publication Sho
The method described in Japanese Patent No. 48-4106 and the like can be mentioned, but manufacturing conditions must be set so that each constituent polymer satisfies the requirements described below. All of the above-mentioned known methods involve block copolymerizing a conjugated diene and a vinyl aromatic hydrocarbon using an anionic polymerization initiator such as an organolithium compound in a hydrocarbon solvent. In the present invention, the polymer structure has the general formula: (a) (A-B) o (b) A(-B-A) o (c) B(-A-B) o (In the above formula, A is vinyl B is a polymer block mainly composed of aromatic hydrocarbons, and B is a polymer block mainly composed of conjugated diene. The boundary between A block and B block does not necessarily need to be clearly distinguished. n is 1 ) or the general formula, (d) [(B-A) o --] n+2 ---X (e) [(A-B) o --] n+2 ---X (f) [(B-A) o --B n+2 ---X (g) [(A-B) o --- A n+2 --- X (In the above formula, A and B are the same as above, and
represents a residue of a coupling agent such as silicon tetrachloride or tin tetrachloride, or a residue of an initiator such as a polyfunctional organolithium compound. m and n are integers of 1 or more. ) or a mixture of these block copolymers with any polymer structure can be used. In the present invention, vinyl aromatic hydrocarbons include styrene, o-methylstyrene, p-methylstyrene, p-tert-butylstyrene, 1,3-dimethylstyrene, α-methylstyrene, vinylnaphthalene, vinylanthracene, etc. However, styrene is a particularly common one.
These may be used not only alone, but also as a mixture of two or more. The conjugated diene is a diolefin having a pair of conjugated double bonds, for example, 1,3
-butadiene, 2-methyl-1,3-butadiene (isoprene), 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 1,3-hexadiene, etc., but particularly common ones include Examples include 1,3-butadiene and isoprene.
These may be used not only alone, but also as a mixture of two or more. The block copolymer of component (A) used in the present invention has a number average molecular weight of 100,000.
~350,000, preferably 130,000 to 300,000, and the number average molecular weight of the vinyl aromatic hydrocarbon polymer block incorporated in the block copolymer is 10,000 to
100,000, preferably 15,000 to 70,000, and the vinyl aromatic hydrocarbon content is 75 to 95% by weight, preferably 77 to 90% by weight. The number average molecular weight of block copolymer (A) is
If the number average molecular weight is less than 100,000, the environmental damage resistance will be poor, and if the number average molecular weight is more than 350,000, the mixability with other components and the processability of the block copolymer mixture will be poor, which is not preferable. Furthermore, if the number average molecular weight of the vinyl aromatic hydrocarbon polymer block incorporated in the block copolymer is less than 10,000, the tensile strength and rigidity will be poor, and if it exceeds 100,000, the low-temperature stretchability and low-temperature shrinkage will be poor. It is not desirable because it has inferior properties. Furthermore, if the vinyl aromatic hydrocarbon content is less than 75% by weight, the tensile strength and rigidity will be poor, and if it exceeds 95% by weight, the impact resistance will be poor, which is not preferable. In addition, in the present invention, the number average molecular weight of a block copolymer is defined as the peak count number and the number average molecular weight of monodisperse polystyrene obtained by GPC of monodisperse polystyrene for gel permeation chromatography (hereinafter referred to as GPC). A calibration curve is prepared, and the number average molecular weight corresponding to the main peak count number of the GPC pattern of the block copolymer is read from the calibration curve. In addition, the number average molecular weight of the vinyl aromatic hydrocarbon polymer block incorporated into the block copolymer is determined by the oxidative decomposition of the block copolymer with di-tertiary butyl hydroperoxide using osmium tetroxide as a catalyst. methods (e.g. LMKOLTHOFF, etal.,
A vinyl aromatic hydrocarbon polymer block component obtained by the method described in J. Polym. Sci. ) is the value calculated by transferring the calibration curve created using monodisperse polystyrene for GCP and following a conventional method (for example, "Gel Chromatography <Basic Edition>" published by Kodansha).Next The block copolymer of component (B) used in the present invention has a vinyl aromatic hydrocarbon content of 50% by weight.
more than 75% by weight, preferably 60-73% by weight
It is. Vinyl aromatic hydrocarbon content is 50% by weight
In the following cases, the compatibility with component (A) will be insufficient and the environmental damage resistance will be poor, and if it exceeds 75% by weight, the environmental damage resistance will deteriorate. In the present invention, the number average molecular weight of the block copolymer (B) is preferably 80,000 to 250,000 in terms of improving environmental damage resistance.
Preferably, a block copolymer of 100,000 to 200,000 is used. There is no particular restriction on the number average molecular weight of the vinyl aromatic hydrocarbon polymer block incorporated into the block copolymer of component (B), but in order to obtain a molded article with better low-temperature shrinkability, Number average molecular weight is 10,000 to 100,000, preferably 15,000 to
It is recommended to use a block copolymer of 70,000. In the present invention, the block copolymer mixture of component (A) and component (B) has a vinyl aromatic hydrocarbon content of 10 to 50% by weight, preferably 15 to 45% by weight as component (C).
By blending and using a block copolymer in an amount of % by weight, impact resistance can be further improved without deteriorating low-temperature shrinkage properties and environmental damage resistance.
As component (C), block copolymers having a number average molecular weight of 20,000 to 250,000, preferably 40,000 to 200,000 can generally be used. In the present invention, the weight ratio of component (A) and component (B) is
The ratio is 30:70 to 95:5, preferably 50:50 to 90:10. If the blending amount of each component is outside this range, it is not preferable because the environmental damage resistance will be poor. Also component (C)
The blending amount is 5 parts by weight or more and 60 parts by weight or less, preferably 5 parts by weight or more and 50 parts by weight or less, based on 100 parts by weight of the total amount of component (A) and component (B). If the amount of component (C) exceeds 60 parts by weight, it is not preferable because tensile strength and rigidity are poor. In the present invention, the block copolymer mixture consisting of component (A), component (B), and component (C) has a flexural modulus of 7,000 to 18,000 Kg/cm 2 , preferably 9,000 to 16,000.
Kg/ cm2 . If the flexural modulus is less than 7000 Kg/cm 2 , the rigidity is poor, and when the heat-shrinkable molded product of the present invention, such as a film or tube, is used as a material for shrink packaging, it may sag during the packaging process and may not be properly packaged. The problem arises that it is difficult to
Moreover, if the flexural modulus exceeds 18,000, it is not preferable because the environmental damage resistance is poor. In the present invention, the flexural modulus refers to the flexural modulus of a block copolymer mixture consisting of component (A), component (B), and component (C).
Values measured based on JIS-K-7203. Particularly suitable block copolymer mixtures in the present invention have a vinyl aromatic hydrocarbon content of 77 to 90% by weight and a block copolymer number average molecular weight of 130,000.
300,000, the number average molecular weight of the vinyl aromatic hydrocarbon polymer block incorporated in the block copolymer is 15,000 to 70,000 as component (A), and the vinyl aromatic hydrocarbon content is 60-73
% by weight, the number average molecular weight of the block copolymer is
100,000 to 200,000, and the number average molecular weight of the vinyl aromatic hydrocarbon polymer block incorporated in the block copolymer is 15,000 to 70,000. The vinyl aromatic hydrocarbon content as component (C) is 15~
45% by weight, the number average molecular weight of the block copolymer is
This is a block copolymer mixture containing 40,000 to 200,000 block copolymers. Heat-shrinkable molded products using these materials have particularly excellent low-temperature shrinkability, with a heat shrinkage rate of 15% or more at 80°C in the stretching direction. In the above preferred embodiment, the ratio (/n) of the weight average molecular weight to the number average molecular weight of the vinyl aromatic hydrocarbon polymer block incorporated into the block copolymer further improves heat shrinkability. A value of less than 1.25 is recommended in terms of The block copolymer used in the present invention may be modified with hydroxyl groups by hydrogenation, halogenation, hydrogen halogenation, epoxidation, or chemical reaction within a range that does not impair its basic properties such as low-temperature shrinkability and rigidity. Modifications such as introduction of functional groups such as thiol groups, nitrile groups, sulfonic acid groups, carboxyl groups, and amino groups may also be performed. In the present invention, a block copolymer mixture (component (a)
A low molecular weight vinyl aromatic hydrocarbon polymer or copolymer (referred to as component (b)) may be blended with the material (referred to as component (b)) for the purpose of improving low-temperature stretchability and low-temperature shrinkability. In addition, for the purpose of further improving low-temperature stretchability, low-temperature shrinkability, and rigidity, the block copolymer may be combined with component (b) and a relatively high molecular weight vinyl aromatic hydrocarbon polymer or copolymer (with component (c)). ) may also be blended. Furthermore, component (c) alone may be blended into the block copolymer for the purpose of improving rigidity. The vinyl aromatic hydrocarbon polymers or copolymers of components (b) and (c) used in the present invention include the above-mentioned vinyl aromatic hydrocarbon monomers or copolymers as well as the above-mentioned vinyl aromatic hydrocarbon polymers or copolymers. Aromatic hydrocarbon monomers and other vinyl monomers, such as ethylene, propylene, butylene, vinyl chloride, vinylidene chloride, vinyl acetate, acrylic esters such as methyl acrylate, methacrylic esters such as methyl methacrylate, acrylonitrile, etc. Contains copolymers. Particularly preferred are styrene homopolymers, styrene and α-methylstyrene copolymers, and styrene and methyl methacrylate copolymers. The number average molecular weight of the low molecular weight vinyl aromatic hydrocarbon polymer or copolymer as component (b) used in the present invention is 20,000 or less, preferably 200 to 10,000, more preferably 300 to 5,000. Number average molecular weight is 20000
Exceeding this is not preferable because the effect of improving low-temperature shrinkage is lost. Particularly preferred are those having a number average molecular weight of 300 or more and less than 500, and such low molecular weight polymers or copolymers have an extremely good effect of improving low-temperature shrinkage properties. The amount of the low molecular weight vinyl aromatic hydrocarbon polymer or copolymer of component (b) is 5 to 100 parts by weight, preferably 10 to 70 parts by weight, based on 100 parts by weight of the block copolymer of component (a). weight part,
More preferably, it is 15 to 55 parts by weight. The number average molecular weight of the relatively high molecular weight vinyl aromatic hydrocarbon polymer or copolymer used as component (c) in the present invention is 30,000 or more, preferably 50,000 or more.
~1,000,000, more preferably 80,000~500,000. If the number average molecular weight of component (c) is less than 30,000, it is not preferable because the effect of improving rigidity is not sufficient. The blending amount of the vinyl aromatic hydrocarbon polymer or copolymer as component (c) is 5 to 80 parts by weight, preferably 10 to 60 parts by weight, based on 100 parts by weight of the block copolymer mixture of component (a). parts, more preferably 15 to 45 parts by weight. Various additives may be added to the block copolymer mixture used in the present invention or the block copolymer composition blended with the above vinyl aromatic hydrocarbon polymer or copolymer depending on the purpose. .
A preferred additive is 30 parts by weight or less of coumarone.
Examples include softeners and plasticizers such as indene resin, terpene resin, and oil. In addition, various stabilizers,
Pigments, antiblocking agents, antistatic agents, lubricants, etc. can also be added. In addition, anti-blocking agents, lubricants,
Examples of antistatic agents include fatty acid amide, ethylene bisstearamide, sorbitan monostearate, saturated fatty acid esters of fatty acid alcohols, pentaerythritol fatty acid esters, and ultraviolet absorbers include pt-butyl phenyl salicylate. , 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-(2'-hydroxy-3'-t-butyl-5'-methylphenyl)
-5-chlorobenzotriazole, 2,5-bis-[5'-t-butylbenzoxazolyl-(2)]thiophene, etc., are listed in "Practical Handbook of Additives for Plastics and Rubber" (Kagaku Kogyosha). These compounds are generally used in a range of 0.01 to 5% by weight, preferably 0.1 to 2% by weight. In the present invention, block copolymerization of component (A), component (B), and component (C) can be used. The combined mixture and other additives can be mixed by any conventionally known compounding method.For example, an open roll, intensive mixer, internal mixer, co-kneader, or continuous kneader with a twin-screw rotor. , a melt-kneading method using a general mixing machine such as an extruder, a method of dissolving or dispersing each component in a solvent, or heating and removing the solvent after mixing, etc. To obtain heat-shrinkable molded articles from the composition,
Basically, the methods used to impart heat-shrinkability to films made of vinyl chloride resin can basically be used, but the heat-shrinkable molded products obtained can be heated at 90°C.
Thermal shrinkage rate is 10% or more, preferably 15-99
%, more preferably 20-80%. If the heat shrinkage rate at 90℃ is less than 10%, low-temperature shrinkability is poor, so it is necessary to adjust the shrink packaging process to a high temperature and uniformity, or to heat it for a long time, which may cause deterioration or deformation at high temperatures. This is undesirable because it makes it impossible to package such items and reduces shrink-wrapping processing capacity. In addition, in the present invention, 90°C
The heat shrinkage rate of a uniaxially stretched or biaxially stretched molded product is the value obtained when the molded product is immersed for 5 minutes in a heating medium such as 90°C hot water, silicone oil, or glycerin that does not affect the properties of the molded product. This is the heat shrinkage rate in each stretching direction. In order to obtain a heat-shrinkable uniaxially or biaxially stretched molded article from the block copolymer mixture or block copolymer composition described above, the block copolymer mixture or block copolymer composition is processed by a conventional T-die or From annular die to flat or tube shape 150~
Extrusion molding is carried out at 250°C, preferably 170 to 220°C, and the resulting unstretched product is uniaxially or biaxially stretched.
For example, in the case of uniaxial stretching, in the case of a film or sheet, it is stretched in the extrusion direction using a calendar roll, etc., or in the direction perpendicular to the extrusion direction using a tenter, etc., and in the case of a tube shape, it is stretched in the extrusion direction of the tube or in the circumferential direction. Stretch. In the case of biaxial stretching, in the case of a film or sheet, the extruded film or sheet is stretched in the longitudinal direction with a metal roll, etc., and then stretched in the transverse direction with a tenter, etc., and in the case of tube-shaped storage, the extruded film or sheet is stretched in the extrusion direction of the tube. and simultaneously or separately in the circumferential direction of the tube, that is, in the direction perpendicular to the tube axis. The heat-shrinkable film or tube of the heat-shrinkable molded article of the present invention obtained in this way generally has a thickness in the range of 5 to 500μ, preferably 10 to 200μ, and more preferably 30 to 100μ. be adjusted. In the present invention, it is preferable to stretch at a stretching temperature of 60 to 120°C, preferably 80 to 110°C, and a stretching ratio of 1.5 to 8 times, preferably 2 to 6 times, in the machine direction and/or the transverse direction. If the stretching temperature is less than 60°C, breakage will occur during stretching, making it difficult to obtain the desired heat-shrinkable molded product, and if it exceeds 120°C, it will be difficult to obtain a product with good low-temperature shrinkability. The stretching ratio is selected within the above range to correspond to the shrinkage ratio required depending on the application, but if the stretching ratio is less than 1.5 times, the heat shrinkage ratio is low and it is not suitable for use in heat-shrinkable packaging. A stretching ratio of more than 8 times is not preferable in terms of stable production in the stretching process. In the case of biaxial stretching,
The stretching ratios in the machine direction and the transverse direction may be the same or different. After uniaxial stretching or 2
The heat-shrinkable molded product after axial stretching is then heated to 60 to 105°C, preferably 80 to 95°C, immediately after cooling if necessary.
for a short time, e.g. 3-60 seconds, preferably 10-40 seconds.
It is also possible to carry out a heat treatment for a second to prevent natural shrinkage at room temperature. When using the uniaxially stretched or biaxially stretched molded product of the present invention as a heat-shrinkable packaging material, the temperature is preferably 150 to 300°C in order to achieve the desired heat shrinkage rate.
At a temperature of 180-250℃ for several seconds to several minutes, preferably 1
It can be heat-shrinked by heating for ~60 seconds, more preferably 2-30 seconds. The uniaxially or biaxially stretched molded products of the present invention are superior in terms of hygiene compared to conventional vinyl chloride resin-based products, and their properties can be utilized for a variety of applications, such as fresh foods, frozen foods, and confectionery. kind of packaging,
It can be used for packaging clothing, stationery, toys, etc. As a particularly preferred application, after printing characters or designs on a uniaxially stretched film of the block copolymer mixture or block copolymer composition defined in the present invention,
It can be used as a so-called heat-shrinkable label material, which is used by heat-shrinking it to adhere tightly to the surface of a packaged object such as a plastic molded product, metal product, glass container, or porcelain. In particular, the film of the uniaxially stretched heat-shrinkable block copolymer mixture or composition of the present invention has excellent low-temperature shrinkability, impact resistance, and environmental damage resistance, so it is suitable for plastics that deform when heated to high temperatures. In addition to heat-shrinkable label materials for molded products, materials with thermal expansion coefficients and water absorption properties that are extremely different from those of the heat-shrinkable molded products of the present invention, such as metals, porcelain, glass, and polyolefin resins such as polyethylene, polypropylene, and polybutene. , polymethacrylic acid ester resin, polycarbonate resin, polyester resin such as polyethylene terephthalate, polybutylene terephthalate, and polyamide resin as a constituent material. Suitable for use as a heat-shrinkable label material for containers. can. In addition to the above-mentioned resins, the materials constituting the plastic container to which the heat-shrinkable molded product of the present invention can be applied include polystyrene, rubber-modified high-impact polystyrene (HIPS), styrene-acrylonitrile copolymer, and styrene-acrylonitrile copolymer. Maleic anhydride copolymer, acrylonitrile-butadiene-styrene copolymer (ABS), methacrylic acid ester-butadiene-styrene copolymer (MBS), polyvinyl chloride resin, polyvinylidene chloride resin, phenolic resin, urea resin , melamine resin, epoxy resin, unsaturated polyester resin, silicone resin, etc. These plastic containers may be a mixture of two or more resins or may be a laminate. In addition, when a heat-shrinkable film obtained by uniaxially stretching the block copolymer mixture defined in the present invention is used as a heat-shrinkable label material, the heat shrinkage rate at 90°C in the direction orthogonal to the stretching direction is is preferably less than 10%, preferably 5% or less, more preferably 3% or less. Examples of the present invention will be shown below to explain the present invention in more detail, but it goes without saying that the content of the present invention is not limited to these Examples. In the following examples, a styrene-butadiene block copolymer having the polymer structure, styrene content, number average molecular weight of the block copolymer, and number average molecular weight of the polystyrene block as shown in Table 1 was used with cyclohexane or n- n in hexane
- Polymerization using butyllithium as an initiator was used.
【表】
実施例1および2、参考例1および比較例1
第2表の配合処法に従つてブロツク共重合体混
合物を40mmφ押出機を用いてそれぞれシート状に
成形した後、約3倍に1軸延伸して厚さ約80μm
のフイルムを作製した。各フイルムの性能を第2
表に示した。
本発明の熱収縮性のフイルムは低温延伸性、低
温収縮性、容器被覆性能、耐環境破壊性能に優れ
ているだけでなく、(C)成分を配合することにより
耐衝撃強度が向上し、熱収縮性ラベル用素材とし
て好適でることが分かる。
尚、実施例1および2の1軸延伸フイルムにお
いて、延伸方向と直交する方向における90℃熱収
縮率は5%未満であつた。[Table] Examples 1 and 2, Reference Example 1 and Comparative Example 1 Each block copolymer mixture was formed into a sheet using a 40 mmφ extruder according to the formulation method shown in Table 2, and then expanded to about 3 times its size. Monoaxially stretched to a thickness of approximately 80μm
A film was produced. The performance of each film is
Shown in the table. The heat-shrinkable film of the present invention not only has excellent low-temperature stretchability, low-temperature shrinkability, container covering performance, and environmental damage resistance, but also has improved impact resistance and heat resistance by incorporating component (C). It can be seen that it is suitable as a material for shrinkable labels. In addition, in the uniaxially stretched films of Examples 1 and 2, the 90°C heat shrinkage rate in the direction orthogonal to the stretching direction was less than 5%.
【表】【table】
【表】
実施例3および参考例2および3
第3表に配合処方に従つてブロツク共重合体混
合物を40mmφ押出機でそれぞれシート状に成形し
た後、2軸延伸装置(岩本製作所)により延伸倍
率3倍で2軸延伸を行つた。押出機の押出温度条
件は、シリンダー温度150℃〜200℃、Tダイ200
℃であり、Tダイより押出されたシートを2軸延
伸装置に通して延伸した。延伸温度は1軸延伸に
おける延伸可能最低温度と同一の温度に設定し
た。各フイルムの性能を第3表に示した。[Table] Example 3 and Reference Examples 2 and 3 The block copolymer mixture was formed into a sheet using a 40 mmφ extruder according to the formulation shown in Table 3, and then the stretching ratio was determined using a biaxial stretching device (Iwamoto Seisakusho). Biaxial stretching was performed at 3x. The extrusion temperature conditions of the extruder are cylinder temperature 150℃~200℃, T die 200℃
℃, and the sheet extruded from the T-die was stretched through a biaxial stretching device. The stretching temperature was set to the same temperature as the lowest possible stretching temperature in uniaxial stretching. The performance of each film is shown in Table 3.
【表】【table】
本発明の熱収縮性成形品は、低温において優れ
た収縮性を有しており、収縮工程において高温で
長時間加熱することのできない、生鮮食料品等の
包装に極めて有効である。
また、耐衝撃性、耐環境破壊特性に優れている
ので取扱いが容易となり、産業上の利用価値は大
きい。
The heat-shrinkable molded article of the present invention has excellent shrinkability at low temperatures and is extremely effective for packaging perishable foods and the like that cannot be heated at high temperatures for long periods of time during the shrinking process. Furthermore, since it has excellent impact resistance and environmental damage resistance, it is easy to handle and has great industrial value.
Claims (1)
を主体とする重合体ブロツクと少なくとも1個
の共役ジエンを主体とする重合体ブロツクを有
し、ビニル芳香族炭化水素含有量が75〜95重量
%であるブロツク共重合体であり、しかも該ブ
ロツク共重合体の数平均分子量が100000〜
350000、該ブロツク共重合体中に組込まれてい
るビニル芳香族炭化水素重合体ブロツクの数平
均分子量が10000〜100000であるブロツク共重
合体、30〜95重量部、 (B) 少なくとも1個のビニル芳香族炭化水素を主
体とする重合体ブロツクと少なくとも1個の共
役ジエンを主体とする重合体ブロツクを有し、
ビニル芳香族炭化水素含有量が50重量%を超
え、75重量%未満であるブロツク共重合体、70
〜5重量部 (C) 少なくとも1個のビニル芳香族炭化水素を主
体とする重合体ブロツクと少なくとも1個の共
役ジエンを主体とする重合体ブロツクを有し、
ビニル芳香族炭化水素含有量が10〜50重量%で
あるブロツク共重合体を前記成分(A)と成分(B)の
合計量100重量部に対して5重量部以上60重量
部以下、 からなり、その曲げ弾性率が7000〜18000Kg/cm2
であるブロツク共重合体混合物を延伸し、延伸方
向における90℃の熱収縮率が10%以上である熱収
縮性成形品。 2 (A) 少なくとも1個のビニル芳香族炭化水素
を主体とする重合体ブロツクと少なくとも1個
の共役ジエンを主体とする重合体ブロツクを有
し、ビニル芳香族炭化水素含有量が75〜95重量
%であるブロツク共重合体であり、しかも該ブ
ロツク共重合体の数平均分子量が100000〜
350000、該ブロツク共重合体中に組込まれてい
るビニル芳香族炭化水素重合体ブロツクの数平
均分子量が10000〜100000であるブロツク共重
合体、30〜95重量部、 (B) 少なくとも1個のビニル芳香族炭化水素を主
体とする重合体ブロツクと少なくとも1個の共
役ジエンを主体とする重合体ブロツクを有し、
ビニル芳香族炭化水素含有量が50重量%を超
え、75重量%未満であるブロツク共重合体、70
〜5重量部 (C) 少なくとも1個のビニル芳香族炭化水素を主
体とする重合体ブロツクと少なくとも1個の共
役ジエンを主体とする重合体ブロツクを有し、
ビニル芳香族炭化水素含有量が10〜50重量%で
あるブロツク共重合体を前記成分(A)と成分(B)の
合計量100重量部に対して5重量部以上60重量
部以下、 からなり、その曲げ弾性率が7000〜18000Kg/cm2
であるブロツク共重合体混合物1軸延伸し、延伸
方向における90℃の熱収縮率が10%以上であるこ
とを特徴とするブロツク共重合体混合物の1軸延
伸ラベル用熱収縮性フイルム。 3 金属、磁器、ガラス、ポリオレフイン系樹
脂、ポリメタクリル酸エステル系樹脂、ポリカー
ボネート系樹脂、ポリエステル系樹脂、ポリアミ
ド系樹脂から選ばれる少なくとも1種を構成素材
又はその一部とする容器のラベリングに適した特
許請求の範囲第2項記載の1軸延伸ラベル用熱収
縮性フイルム。[Scope of Claims] 1 (A) A polymer block containing at least one vinyl aromatic hydrocarbon and at least one polymer block mainly consisting of a conjugated diene, and containing a vinyl aromatic hydrocarbon. A block copolymer in which the amount is 75 to 95% by weight, and the number average molecular weight of the block copolymer is 100,000 to 100,000.
350,000, 30 to 95 parts by weight of a block copolymer in which the vinyl aromatic hydrocarbon polymer block incorporated in the block copolymer has a number average molecular weight of 10,000 to 100,000; (B) at least one vinyl It has a polymer block mainly composed of an aromatic hydrocarbon and a polymer block mainly composed of at least one conjugated diene,
Block copolymer with a vinyl aromatic hydrocarbon content of more than 50% and less than 75% by weight, 70
~5 parts by weight (C) having at least one polymer block mainly composed of vinyl aromatic hydrocarbon and at least one polymer block mainly composed of conjugated diene,
Consisting of 5 parts by weight or more and 60 parts by weight or less of a block copolymer having a vinyl aromatic hydrocarbon content of 10 to 50% by weight, based on 100 parts by weight of the total amount of component (A) and component (B). , its bending modulus is 7000~18000Kg/ cm2
A heat-shrinkable molded product obtained by stretching a block copolymer mixture that has a heat shrinkage rate of 10% or more at 90°C in the stretching direction. 2 (A) It has at least one polymer block mainly composed of vinyl aromatic hydrocarbon and at least one polymer block mainly composed of conjugated diene, and the vinyl aromatic hydrocarbon content is 75 to 95% by weight. %, and the number average molecular weight of the block copolymer is 100,000 to 100,000.
350,000, 30 to 95 parts by weight of a block copolymer in which the vinyl aromatic hydrocarbon polymer block incorporated in the block copolymer has a number average molecular weight of 10,000 to 100,000; (B) at least one vinyl It has a polymer block mainly composed of an aromatic hydrocarbon and a polymer block mainly composed of at least one conjugated diene,
Block copolymer with a vinyl aromatic hydrocarbon content of more than 50% and less than 75% by weight, 70
~5 parts by weight (C) having at least one polymer block mainly composed of vinyl aromatic hydrocarbon and at least one polymer block mainly composed of conjugated diene,
Consisting of 5 parts by weight or more and 60 parts by weight or less of a block copolymer having a vinyl aromatic hydrocarbon content of 10 to 50% by weight, based on 100 parts by weight of the total amount of component (A) and component (B). , its bending modulus is 7000~18000Kg/ cm2
A heat-shrinkable film for a uniaxially stretched label made of a block copolymer mixture, characterized in that the block copolymer mixture is uniaxially stretched and has a heat shrinkage rate of 10% or more at 90°C in the stretching direction. 3 Suitable for labeling containers whose constituent material or part thereof is at least one selected from metal, porcelain, glass, polyolefin resin, polymethacrylate resin, polycarbonate resin, polyester resin, and polyamide resin. A heat-shrinkable film for uniaxially stretched labels according to claim 2.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP6827490A JPH02269129A (en) | 1990-03-20 | 1990-03-20 | Heat shrinkable molded article |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP6827490A JPH02269129A (en) | 1990-03-20 | 1990-03-20 | Heat shrinkable molded article |
Related Parent Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP5916583A Division JPS59184620A (en) | 1983-04-06 | 1983-04-06 | Thermocontracting molded article |
Publications (2)
Publication Number | Publication Date |
---|---|
JPH02269129A JPH02269129A (en) | 1990-11-02 |
JPH0432098B2 true JPH0432098B2 (en) | 1992-05-28 |
Family
ID=13369016
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP6827490A Granted JPH02269129A (en) | 1990-03-20 | 1990-03-20 | Heat shrinkable molded article |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH02269129A (en) |
Families Citing this family (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE602004020979D1 (en) * | 2003-03-19 | 2009-06-18 | Denki Kagaku Kogyo Kk | LINEAR BLOCK COPOLYMER CONTAINING COMPOSITION |
JP4787480B2 (en) * | 2004-09-24 | 2011-10-05 | 電気化学工業株式会社 | Resin modifier and thermoplastic resin composition |
JP4708048B2 (en) * | 2005-02-23 | 2011-06-22 | 信越ポリマー株式会社 | Styrenic resin sheet and embossed carrier tape |
CN112424883B (en) * | 2018-08-27 | 2022-07-08 | 住友电气工业株式会社 | Electrically insulated cable |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS59184620A (en) * | 1983-04-06 | 1984-10-20 | Asahi Chem Ind Co Ltd | Thermocontracting molded article |
-
1990
- 1990-03-20 JP JP6827490A patent/JPH02269129A/en active Granted
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS59184620A (en) * | 1983-04-06 | 1984-10-20 | Asahi Chem Ind Co Ltd | Thermocontracting molded article |
Also Published As
Publication number | Publication date |
---|---|
JPH02269129A (en) | 1990-11-02 |
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