JP4392632B2 - Biodegradable food container with hot water resistance and oil resistance - Google Patents
Biodegradable food container with hot water resistance and oil resistance Download PDFInfo
- Publication number
- JP4392632B2 JP4392632B2 JP36562499A JP36562499A JP4392632B2 JP 4392632 B2 JP4392632 B2 JP 4392632B2 JP 36562499 A JP36562499 A JP 36562499A JP 36562499 A JP36562499 A JP 36562499A JP 4392632 B2 JP4392632 B2 JP 4392632B2
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- zein
- shellac
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- 235000013305 food Nutrition 0.000 title claims description 75
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 title claims description 54
- 229920002494 Zein Polymers 0.000 claims description 168
- 239000005019 zein Substances 0.000 claims description 168
- 229940093612 zein Drugs 0.000 claims description 168
- 229920001800 Shellac Polymers 0.000 claims description 98
- 239000004208 shellac Substances 0.000 claims description 98
- ZLGIYFNHBLSMPS-ATJNOEHPSA-N shellac Chemical compound OCCCCCC(O)C(O)CCCCCCCC(O)=O.C1C23[C@H](C(O)=O)CCC2[C@](C)(CO)[C@@H]1C(C(O)=O)=C[C@@H]3O ZLGIYFNHBLSMPS-ATJNOEHPSA-N 0.000 claims description 98
- 229940113147 shellac Drugs 0.000 claims description 98
- 235000013874 shellac Nutrition 0.000 claims description 98
- 238000004806 packaging method and process Methods 0.000 claims description 20
- 239000007788 liquid Substances 0.000 claims description 18
- 238000000034 method Methods 0.000 claims description 18
- 239000000203 mixture Substances 0.000 claims description 14
- 239000007787 solid Substances 0.000 claims description 8
- 239000003795 chemical substances by application Substances 0.000 claims description 5
- 238000005452 bending Methods 0.000 claims description 2
- 239000003921 oil Substances 0.000 description 70
- 235000019198 oils Nutrition 0.000 description 70
- 239000000243 solution Substances 0.000 description 60
- 239000010408 film Substances 0.000 description 45
- 238000012360 testing method Methods 0.000 description 43
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 26
- 238000000576 coating method Methods 0.000 description 20
- 230000000052 comparative effect Effects 0.000 description 16
- 239000011248 coating agent Substances 0.000 description 15
- 239000000835 fiber Substances 0.000 description 13
- 230000035515 penetration Effects 0.000 description 12
- 238000010411 cooking Methods 0.000 description 11
- 235000013611 frozen food Nutrition 0.000 description 9
- 235000012149 noodles Nutrition 0.000 description 9
- 230000014759 maintenance of location Effects 0.000 description 8
- -1 polypropylene Polymers 0.000 description 8
- 239000011259 mixed solution Substances 0.000 description 7
- 239000002689 soil Substances 0.000 description 7
- 229920003002 synthetic resin Polymers 0.000 description 7
- 239000000057 synthetic resin Substances 0.000 description 7
- 240000008415 Lactuca sativa Species 0.000 description 6
- 238000011156 evaluation Methods 0.000 description 6
- 239000004745 nonwoven fabric Substances 0.000 description 6
- 235000012045 salad Nutrition 0.000 description 6
- 235000015228 chicken nuggets Nutrition 0.000 description 5
- 239000003925 fat Substances 0.000 description 5
- 239000000463 material Substances 0.000 description 5
- 238000000465 moulding Methods 0.000 description 5
- 235000011962 puddings Nutrition 0.000 description 5
- 229920001661 Chitosan Polymers 0.000 description 4
- 235000014113 dietary fatty acids Nutrition 0.000 description 4
- 229930195729 fatty acid Natural products 0.000 description 4
- 239000000194 fatty acid Substances 0.000 description 4
- 235000015220 hamburgers Nutrition 0.000 description 4
- 238000002156 mixing Methods 0.000 description 4
- 239000012466 permeate Substances 0.000 description 4
- PEDCQBHIVMGVHV-UHFFFAOYSA-N Glycerine Chemical compound OCC(O)CO PEDCQBHIVMGVHV-UHFFFAOYSA-N 0.000 description 3
- 244000061456 Solanum tuberosum Species 0.000 description 3
- 235000002595 Solanum tuberosum Nutrition 0.000 description 3
- 230000004308 accommodation Effects 0.000 description 3
- 239000000853 adhesive Substances 0.000 description 3
- 230000001070 adhesive effect Effects 0.000 description 3
- 230000008859 change Effects 0.000 description 3
- 235000013372 meat Nutrition 0.000 description 3
- 244000005700 microbiome Species 0.000 description 3
- 239000010813 municipal solid waste Substances 0.000 description 3
- 238000010979 pH adjustment Methods 0.000 description 3
- 239000004014 plasticizer Substances 0.000 description 3
- 229920000728 polyester Polymers 0.000 description 3
- 230000009467 reduction Effects 0.000 description 3
- 230000037303 wrinkles Effects 0.000 description 3
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 description 2
- 241000972773 Aulopiformes Species 0.000 description 2
- 108010068370 Glutens Proteins 0.000 description 2
- 239000004698 Polyethylene Substances 0.000 description 2
- 239000004743 Polypropylene Substances 0.000 description 2
- 239000004793 Polystyrene Substances 0.000 description 2
- 229920001131 Pulp (paper) Polymers 0.000 description 2
- 229930006000 Sucrose Natural products 0.000 description 2
- 240000008042 Zea mays Species 0.000 description 2
- 235000005824 Zea mays ssp. parviglumis Nutrition 0.000 description 2
- 235000002017 Zea mays subsp mays Nutrition 0.000 description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 2
- 231100000209 biodegradability test Toxicity 0.000 description 2
- 235000005822 corn Nutrition 0.000 description 2
- 235000021438 curry Nutrition 0.000 description 2
- 238000003912 environmental pollution Methods 0.000 description 2
- 235000021312 gluten Nutrition 0.000 description 2
- 235000011187 glycerol Nutrition 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 238000005470 impregnation Methods 0.000 description 2
- 235000015110 jellies Nutrition 0.000 description 2
- 239000008274 jelly Substances 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
- 230000008018 melting Effects 0.000 description 2
- 239000005445 natural material Substances 0.000 description 2
- 229920000573 polyethylene Polymers 0.000 description 2
- 229920001155 polypropylene Polymers 0.000 description 2
- 229920002223 polystyrene Polymers 0.000 description 2
- 235000019515 salmon Nutrition 0.000 description 2
- 239000003549 soybean oil Substances 0.000 description 2
- 235000012424 soybean oil Nutrition 0.000 description 2
- 239000005720 sucrose Substances 0.000 description 2
- 239000004094 surface-active agent Substances 0.000 description 2
- 239000012209 synthetic fiber Substances 0.000 description 2
- 229920002994 synthetic fiber Polymers 0.000 description 2
- 229920001169 thermoplastic Polymers 0.000 description 2
- 239000004416 thermosoftening plastic Substances 0.000 description 2
- 235000015112 vegetable and seed oil Nutrition 0.000 description 2
- 239000008158 vegetable oil Substances 0.000 description 2
- KVGZZAHHUNAVKZ-UHFFFAOYSA-N 1,4-Dioxin Chemical compound O1C=COC=C1 KVGZZAHHUNAVKZ-UHFFFAOYSA-N 0.000 description 1
- IIZPXYDJLKNOIY-JXPKJXOSSA-N 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphocholine Chemical compound CCCCCCCCCCCCCCCC(=O)OC[C@H](COP([O-])(=O)OCC[N+](C)(C)C)OC(=O)CCC\C=C/C\C=C/C\C=C/C\C=C/CCCCC IIZPXYDJLKNOIY-JXPKJXOSSA-N 0.000 description 1
- QTBSBXVTEAMEQO-UHFFFAOYSA-M Acetate Chemical compound CC([O-])=O QTBSBXVTEAMEQO-UHFFFAOYSA-M 0.000 description 1
- 241000609240 Ambelania acida Species 0.000 description 1
- 244000025254 Cannabis sativa Species 0.000 description 1
- 235000012766 Cannabis sativa ssp. sativa var. sativa Nutrition 0.000 description 1
- 235000012765 Cannabis sativa ssp. sativa var. spontanea Nutrition 0.000 description 1
- 240000000797 Hibiscus cannabinus Species 0.000 description 1
- 241001148717 Lygeum spartum Species 0.000 description 1
- 240000007594 Oryza sativa Species 0.000 description 1
- 235000007164 Oryza sativa Nutrition 0.000 description 1
- 235000019482 Palm oil Nutrition 0.000 description 1
- 239000004952 Polyamide Substances 0.000 description 1
- 229920000297 Rayon Polymers 0.000 description 1
- 235000019485 Safflower oil Nutrition 0.000 description 1
- 108010073771 Soybean Proteins Proteins 0.000 description 1
- 229920002472 Starch Polymers 0.000 description 1
- PPBRXRYQALVLMV-UHFFFAOYSA-N Styrene Chemical group C=CC1=CC=CC=C1 PPBRXRYQALVLMV-UHFFFAOYSA-N 0.000 description 1
- 235000021307 Triticum Nutrition 0.000 description 1
- 244000098338 Triticum aestivum Species 0.000 description 1
- 229920002522 Wood fibre Polymers 0.000 description 1
- 239000013543 active substance Substances 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 239000012298 atmosphere Substances 0.000 description 1
- 239000010905 bagasse Substances 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 235000013361 beverage Nutrition 0.000 description 1
- 238000006065 biodegradation reaction Methods 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 235000009120 camo Nutrition 0.000 description 1
- 235000005607 chanvre indien Nutrition 0.000 description 1
- 229940045110 chitosan Drugs 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 150000002013 dioxins Chemical class 0.000 description 1
- 230000035622 drinking Effects 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000000839 emulsion Substances 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 238000011049 filling Methods 0.000 description 1
- 235000013312 flour Nutrition 0.000 description 1
- 239000011888 foil Substances 0.000 description 1
- 239000010794 food waste Substances 0.000 description 1
- 230000004927 fusion Effects 0.000 description 1
- 150000004676 glycans Chemical class 0.000 description 1
- 239000011487 hemp Substances 0.000 description 1
- 239000005556 hormone Substances 0.000 description 1
- 229940088597 hormone Drugs 0.000 description 1
- 238000007731 hot pressing Methods 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 235000010445 lecithin Nutrition 0.000 description 1
- 229940067606 lecithin Drugs 0.000 description 1
- 239000000787 lecithin Substances 0.000 description 1
- 239000006082 mold release agent Substances 0.000 description 1
- 235000013557 nattō Nutrition 0.000 description 1
- 235000015097 nutrients Nutrition 0.000 description 1
- 235000016709 nutrition Nutrition 0.000 description 1
- 230000035764 nutrition Effects 0.000 description 1
- 239000004006 olive oil Substances 0.000 description 1
- 235000008390 olive oil Nutrition 0.000 description 1
- 239000002540 palm oil Substances 0.000 description 1
- 230000000149 penetrating effect Effects 0.000 description 1
- 230000035699 permeability Effects 0.000 description 1
- 229920002647 polyamide Polymers 0.000 description 1
- 238000006116 polymerization reaction Methods 0.000 description 1
- 229920000098 polyolefin Polymers 0.000 description 1
- 229920001282 polysaccharide Polymers 0.000 description 1
- 239000005017 polysaccharide Substances 0.000 description 1
- 235000012015 potatoes Nutrition 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 239000002964 rayon Substances 0.000 description 1
- 235000009566 rice Nutrition 0.000 description 1
- 235000005713 safflower oil Nutrition 0.000 description 1
- 239000003813 safflower oil Substances 0.000 description 1
- 235000012046 side dish Nutrition 0.000 description 1
- 229920002545 silicone oil Polymers 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 235000019710 soybean protein Nutrition 0.000 description 1
- 235000019698 starch Nutrition 0.000 description 1
- 239000008107 starch Substances 0.000 description 1
- 235000013547 stew Nutrition 0.000 description 1
- 239000010902 straw Substances 0.000 description 1
- 239000010409 thin film Substances 0.000 description 1
- 230000036962 time dependent Effects 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
- 230000003313 weakening effect Effects 0.000 description 1
- 239000002025 wood fiber Substances 0.000 description 1
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A40/00—Adaptation technologies in agriculture, forestry, livestock or agroalimentary production
- Y02A40/90—Adaptation technologies in agriculture, forestry, livestock or agroalimentary production in food processing or handling, e.g. food conservation
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W90/00—Enabling technologies or technologies with a potential or indirect contribution to greenhouse gas [GHG] emissions mitigation
- Y02W90/10—Bio-packaging, e.g. packing containers made from renewable resources or bio-plastics
Landscapes
- Package Specialized In Special Use (AREA)
- Packages (AREA)
- Wrappers (AREA)
- Cookers (AREA)
Description
【０００１】
【発明の属する技術分野】
本発明は、耐熱水性及び耐油性を具備した生分解性の食品容器に関し、食品を収容したまま電子レンジ、オーブン、熱湯などで加熱調理することができ、焼却の必要がなく、そのまま土壌中に簡便に廃棄できるものを提供する。
【０００２】
【発明の背景】
例えば、カップ麺容器はポリスチレン、ポリプロピレン、ポリエステル等の合成樹脂製、或はポリエチレンなどのラミネート紙製であり、また、容器の接着にも合成樹脂系の粘・接着剤が使用されているため、燃焼させるとダイオキシンなどの環境汚染の危険がある。しかも、最近では、当該容器からスチレンモノマーなどの環境ホルモンが微量溶け出す恐れも指摘されている。
一方、グラタン、カレー、チキンナゲット、ハンバーグ、肉じゃがなどの冷凍食品用の容器は、アルミニウム箔、或は合成樹脂製が多く、やはり燃やすと環境汚染の危険があるため、広く食品容器においては、環境保全とゴミの減量などの見地から、燃やさないで土壌中で微生物によって分解処理できる天然素材品への要求が高まっている。
【０００３】
天然素材を食品容器に活用するためには、成形性が必要である。
成形性を有する天然素材としては、例えば、シェラック、キトサン、ゼインなどが挙げられる。
しかしながら、シェラックは常温でも重合促進するうえ、融点が８０℃前後であるため、カップ麺容器などに適用すると、加熱調理の際の耐熱湯性に問題がある。
また、シェラック皮膜は硬いために、皿状に折り曲げ、又はしわ寄せ成形するとストレスがかかった部位にヒビ割れ(クラック)が生じ易く、食品を収容した場合にこのヒビ割れ箇所から食品に含有される油分などが染み込んでしまうという問題もある。これを回避するため、グリセリンなどの可塑剤を混合することも考えられるが、成形容器を用いて熱水調理をした場合、可塑剤が溶出する危険がある。そのうえ、可塑剤を３％以上混合するとシェラック皮膜自体の耐油性が低下してしまう弊害もある。
一方、キトサン皮膜はシェラックより軟らかいが、皮膜形成にはアルカリで中性化する必要があり、ｐＨ調整処理が煩雑である。
これに対して、ゼインは成形時のストレスでも割れにくく、ｐＨ調整の煩雑さもない。
【０００４】
【従来の技術】
ゼインを用いた成形容器の従来技術を挙げると、次の通りである。
(1)従来技術１(特開平１０−２９５３３８号公報)
小麦粉、スターチ、大豆蛋白などを材質とする可食性容器にゼインで被覆処理したレンジ加熱対応容器、或は、当該可食性容器に直接ゼインを添加したレンジ加熱対応容器が開示されている。後者の容器では、例えば、ゼインを約６０％含むコーングルテンを食品素材として使用し、また、食品素材全体のゼインの量が適正範囲である場合には、新たにゼインを添加することなく、コーングルテンで容器を成形することも含まれる。
【０００５】
(2)従来技術２(特開平６−２３４８６９号公報)
濃度６５〜７５ｖ／ｖ％のアセトン水溶液にゼインを分散させたゼイン溶液をモナカの皮などの生分解性器材の表面に塗布し、当該器材を相対湿度８５％以下の雰囲気下で、且つ、加熱開始温度５５℃以下の条件で乾燥して、実用的な耐水性のゼイン薄膜を有する器材を製造する方法が開示されている。
【０００６】
【発明が解決しようとする課題】
上記従来技術１〜２は、共に可食性容器にゼインの皮膜を被覆し、或は、当該容器にゼインを一体的に含有させたものであって、容器全体が可食性である。
このため、食品を喫食する際に、容器も同時に食することになり、廃棄物が出ないという利点はあるが、その反面、例えば、当該技術をカップ麺用の容器、或はグラタン、シチューなどの冷凍食品用の容器などに適用すると、加熱調理の際に保形性などの点で強度不足になることが大きな問題である。
【０００７】
本発明は、充分な保形強度と、耐熱水性及び耐油性とを具備するとともに、生分解性を有して環境汚染の防止やゴミの減量に有効な食品容器を開発することを技術的課題とする。
【０００８】
【発明が解決しようとする課題】
本発明者らは、紙を材質とする包装容器にゼインの含有液を所定の付着量で塗布又は含浸すると、ヒビ割れを起こさずに紙の繊維層を円滑に被覆できること、また、得られた食品容器は全体が生分解性でありながら、充分な保形強度と、耐熱水性及び耐油性とを兼備させることができることを見い出し、本発明を完成した。
【０００９】
即ち、本発明１は、紙を成形した食品収容可能な包装容器であって、
少なくとも上記包装容器の収容空間に臨む内壁側にゼイン液を塗布又は含浸処理して当該内壁面上にゼインの皮膜を形成するとともに、
上記包装容器を構成する紙に対する固形分としてのゼインの付着量が１.０〜３５ｇ／ｍ2であることを特徴とする耐熱水性及び耐油性を有する生分解性食品容器である。
【００１０】
本発明２は、上記本発明１のゼインの皮膜に代えて、ゼインとシェラックの積層皮膜を形成するとともに、
包装容器を構成する紙に対するゼイン及びシェラックの合計付着量が１.０〜３５ｇ／ｍ2であることを特徴とする耐熱水性及び耐油性を有する生分解性食品容器である。
【００１１】
本発明３は、上記本発明１のゼイン液に代えて、ゼイン５０重量％以上／シェラック５０重量％以下の割合であるゼイン及びシェラックの混合物からなる液を用いるとともに、
包装容器を構成する紙に対する上記混合物の付着量が１.０〜３５ｇ／ｍ2であることを特徴とする耐熱水性及び耐油性を有する生分解性食品容器である。
【００１２】
本発明４は、上記本発明１〜３のいずれかの包装容器が、シート状の紙を折り曲げ方式又はしわ寄せ方式で一体成形した深皿状又はカップ状の容器であることを特徴とする耐熱水性及び耐油性を有する生分解性食品容器である。
【００１３】
本発明５は、上記本発明１〜４のいずれかにおいて、包装容器の少なくとも内壁側のゼイン皮膜、ゼインとシェラックの積層皮膜、或はゼインとシェラックの混合皮膜の上に離型剤を被覆することを特徴とする請求項１〜４のいずれか１項に記載の耐熱水性及び耐油性を有する生分解性食品容器である。
【００１４】
【発明の実施の形態】
本発明は紙を基本材質とする食品容器であり、具体的には、第一に、この紙にゼインを被覆した容器、第二に、紙にゼインとシェラックを積層した容器、第三に、紙にゼイン及びシェラックの混合物を被覆した容器である。
本発明の紙は、繊維組成物を湿式抄造した紙又は不織布などを含む広い概念である。湿式抄造する繊維組成物としては、製紙用に通常使用されるＮＢＫＰ、ＬＢＫＰ等の木材パルプ、脱墨パルプ、リンターパルプ、麻、ケナフ、バガス、エスパルト草、ワラ等の非木材繊維パルプ、或はレーヨン、キュプラ、アセテート等の再生繊維などをいう。
一方、通常の不織布は、ポリオレフィン繊維、ポリエステル繊維、ポリアミド繊維などの熱可塑性合成繊維をスパンボンド、サーマルボンド、メルトブローなどの方式で製造されるが、本発明の食品容器は生分解性を具備することが必要である。このため、容器に用いる不織布は、このような熱可塑性合成繊維を材質とした不織布ではなく、前記天然系或は再生系の繊維組成物で湿式抄紙したシート状物に向けて高圧水柱流を噴出させ、繊維組成物の繊維同士を絡合させて一体化した水流絡合不織布などを採用することが好ましい。
【００１５】
上記食品容器は、シート状の紙(抄造紙或は不織布)を折り曲げ方式又はしわ寄せ方式で容器に一体成形し(本発明４参照)、或は、多糖類などの天然物質系の接着剤で当該シート状の紙を貼り合わせて容器を形成するなどの外、公知の方式で形成しても良い。上記折り曲げ方式は、紙の展開図を折り畳んで容器に形成するもので、一般的な紙器製造の方式である。上記しわ寄せ方式は、シート状の紙に１００℃、或はそれ以上に加熱した型を押し当てて容器形状に成形する(即ち、深絞りする)ものである。
上記食品容器の形状は底浅のトレー形状、底深のカップ形状など任意の形状をとり得る。
また、紙の表面に熱プレス加工などを施すと、紙表面の繊維による粗い凹凸が低減され、ゼイン液、ゼイン／シェラック混合液などの塗着効率が増大する。
【００１６】
本発明１のゼイン被覆容器では、例えば、先ず、ゼインを７０〜９０％濃度のエタノールに溶解させ、このゼインのエタノール溶液に上記包装容器を浸漬して含浸処理するか、或は、刷毛などで当該ゼイン溶液を容器に塗布処理する。
上記含浸又は塗布処理では、同じ付着量の場合でも、１回だけで処理するよりも複数回の処理を繰り返す方がゼインを紙の繊維表面に一層均一に付着できる。
また、ゼイン溶液の濃度は１０〜２０重量％程度が好ましい。ゼイン溶液は、通常、濃度の濃い方が紙の繊維内部に浸透してしまう程度が抑制されるため、紙表面にとどまってゼイン皮膜をより円滑に形成できる。
上記ゼイン溶液の食品容器への含浸又は塗布処理は、少なくとも当該食品容器の収容空間に臨む内壁側に施すことが必要であり、従って、包装容器の内壁側及び外壁側の両方に含浸又は塗布する両面(即ち、容器の全面)被覆方式でも良いし、内壁側のみに含浸又は塗布する片面被覆方式でも差し支えない。
【００１７】
本発明２の食品容器は、上記本発明１のゼインを単独被覆した容器に代えて、ゼインとシェラックを積層被覆した容器である。
シェラック液の塗布又は含浸処理は上記ゼイン液のそれと同様である。シェラック液としては、シェラックのエタノール溶液が一般的であり、その濃度は５〜５０重量％程度が好ましい。
前述したように、シェラックの融点は８０℃前後であり、例えば、紙をしわ寄せ成形するには、１００℃前後、或はそれ以上の加熱成形を施す必要があるため、シェラックの塗布面に成形型を押圧すると、熱融着を起こす恐れがある。
従って、紙製の包装容器の表面上に施すゼインとシェラックの積層皮膜としては、最外膜にゼイン皮膜を被覆するのが好ましい。
具体的には、次の▲１▼〜▲２▼の積層皮膜が好適であるが、▲３▼の積層皮膜を排除するものではない。
▲１▼(紙面側)シェラック皮膜／ゼイン皮膜(外側)
▲２▼(紙面側)ゼイン皮膜／シェラック皮膜／ゼイン皮膜(外側)
▲３▼(紙面側)ゼイン皮膜／シェラック皮膜(外側)
【００１８】
本発明３の食品容器は、上記本発明２のゼインとシェラックを積層被覆した容器に代えて、ゼインとシェラックを混合被覆した(即ち、ゼインとシェラックの混合物を被覆した)ものである。
上記ゼインとシェラックの混合物の場合、ゼイン／シェラックの混合割合は、ゼイン５０重量％以上／シェラック５０重量％以下であり、好ましくはゼイン７０重量％以上／シェラック３０重量％以下である。
シェラックの混合はコスト低減に寄与するが、シェラックの含有率が５０重量％以上に増すと、上述したように、皮膜硬度が硬くなり過ぎて割れを生じる恐れがある。特に、シート状の紙に当該混合物を含浸又は塗布して折り曲げ、或はしわ寄せ成形すると、ヒビ割れを起こし易くなるので、当該混合割合には注意を要する。
【００１９】
本発明１のゼイン単独被覆ではゼイン溶液を、本発明２のゼインとシェラックの積層被覆ではゼイン溶液とシェラック溶液を重ね塗り方式で、或は、本発明３の混合被覆ではゼインとシェラックの混合液を包装容器に夫々付着させるのであり、その付着量は、例えば、本発明１では、ゼイン溶液全体の使用量を意味するものではなく、付着後にエタノールなどの溶媒が蒸発して残る固形分としてのゼインの量(即ち、溶液中のゼインの含有量)であり、本発明２〜３では、固形分としてのゼインとシェラックの合計量である。
具体的には、上記付着量は１.０〜３５ｇ／ｍ2であり、好ましくは１０〜２０ｇ／ｍ2である。上記付着量が１.０ｇ／ｍ2より少ないと、特に、耐油性が低下する恐れがある。逆に、３５ｇ／ｍ2を越えると、容器を折り曲げた場合にクラックが発生し易く、このクラック部分から液体が浸透して耐水性、耐油性が低下する恐れがある。
また、本発明２のゼインとシェラックの積層被覆、或は、本発明３の混合被覆の食品容器にあっては、食品容器に対する含浸又は塗布処理は、上記本発明１と同様に、少なくとも食品容器の収容空間に臨む内壁側に施せば足りる。
さらに、所定の付着量を塗布又は含浸する場合、１回で処理しても良いが、塗膜の均一性、平滑性などを確保する見地から、複数回に分けて塗布処理などを行う方が好ましいことは、上記本発明１と同じである。
【００２０】
本発明５の離型剤は、可食性界面活性剤、植物油、シリコン油、豚脂、ラードなどであり、可食性界面活性剤としては、グリセリン脂肪酸エステル、ショ糖脂肪酸エステル、ソルビタン脂肪酸エステル、レシチン、キトサンなどが挙げられる。植物油としては、大豆油、パーム油、紅花油、ヌカ油、オリーブ油などが挙げられる。
上記離型剤は食品容器から調理済み食品を円滑に剥離し、或は容器を構成する紙の繊維が食品に噛み込むのを防止するためのものであることから、食品容器に被覆した本発明１のゼイン皮膜、本発明２のゼインとシェラックの積層皮膜、或は本発明３の混合皮膜のうち、少なくとも食品容器の内壁側の皮膜上に当該離型剤を被覆すれば良い。
【００２１】
上記食品容器の形状は、浅皿状のトレー、深皿状のカップを初め、任意の形状をとり得る。
本発明の食品容器は、グラタン、ドリア、カレー、チキンナゲット、鯖の煮付け、肉じゃが、ハンバーグ、炒麺、シュマイ、ギョーザなどの冷凍食品を収容する容器、カップ麺用の容器、或は、プリン、ゼリーなどの容器を初め、任意の食品容器として適用できる。
従って、当該食品容器の使用形態としては、グラタンなどの冷凍食品を収容したまま電子レンジ、オーブンなどで加熱調理したり、カップ麺のようにお湯を注いで調理したり、或は、プリンなどの熱いゾル液を充填して冷却することなどが挙げられ、当該加熱調理条件の下でも、本発明の食品容器は実用的な耐久性(具体的には、保形性)を具備することができる。
【００２２】
【発明の効果】
(1)紙を成形した包装容器にゼインの皮膜、ゼインとシェラックの積層皮膜、或はゼインとシェラックの混合皮膜を適正な付着量で被覆した食品容器であるため、グラタン、チキンナゲット、鯖の煮付けなどの冷凍食品を収容して電子レンジなどで加熱調理しても、食品の油分や水分が紙に浸透することがなく、容器の保形性を確実に保持できる。また、カップ麺用の容器に用いた場合にも、熱湯が紙に浸透するのを防止し、やはり保形性を充分に保持できる。
即ち、本発明の食品容器は、チキンナゲット、グラタンなどのような油分の多い食品、或は、鯖の煮付け、肉じゃがなどのような水分の多い食品の種類を問わず、レンジ調理などにおける耐久性を充分に確保できるため、従来のポリスチレン、ポリプロピレン、ポリエステルなどの合成樹脂製、或はポリエチレンなどのラミネート紙製の容器の代替品として好適である。
しかも、電子レンジ、オーブン、熱湯などで加熱調理した後の処分方法としては、従来の合成樹脂製の食品容器とは異なり、そのまま土壌中に廃棄しても微生物によって簡便に分解されるため、環境を有効に保全できる。また、上記合成樹脂製の容器のように焼却する必要がないため、ゴミ量の低減にも有用である。
尚、本発明の食品容器は、油分や水分の多い食品に対して良好な保形性を持続するため、加熱調理せずに飲食する食品、例えば、納豆、サラダ、各種惣菜類、プリン、或は、各種飲料などの容器としても好適である。また、生分解性を有する本発明の容器は、飲食した後にいわば生ゴミとして土壌中にそのまま廃棄できるうえ、燃焼時にダイオキシンなどが発生する恐れもないことから、合成樹脂製の容器に比べて廃棄処理コストを低減できる。
【００２３】
(2)本発明１のゼインを単用被覆した食品容器では、後述の試験例に示すように、シェラックなどの単用皮膜に比べて皮膜硬度が軟らかく、シート状の紙を折り曲げ方式で、或はしわ寄せ方式で容器に一体成形しても、クラックの恐れがない。このため、食品を収容した場合に、容器に生じたクラックから食品の油分、水分が浸透して、容器の保形性が弱体化することを円滑に防止できる。また、キトサンで皮膜形成する場合のように、ｐＨ調整などの煩雑な手間も要らない。
【００２４】
(3)本発明２のゼインとシェラックの積層皮膜、或は本発明３の混合皮膜は、後述の試験例に示すように、ゼイン単用の皮膜に類した耐熱水性及び耐油性を示すとともに、シェラックの単用皮膜に比べて皮膜硬度は軟らかく、クラックの発生を実用レベルで有効に防止できる。
また、本発明１のゼインを単用被覆した食品容器に比べて、安価なシェラックを積層又は混合する分だけ、コスト削減に有効である。
【００２５】
(4)本発明５では、油脂などの離型剤をゼイン皮膜、ゼインとシェラックの積層皮膜、又は混合皮膜の上に被覆するため、調理した食品を容器から簡便に剥離することができる。
例えば、プリンやゼリーなどの容器として用いる場合、これらの熱ゾル液を容器に入れて冷却した際に、ゲル化したプリンなどを容器からスムーズに取り出すことができる。
【００２６】
【実施例】
以下、ゼインなどを被覆した紙を用いて、ゼイン溶液などの付着量の変化、折り曲げ処理の有・無などに伴う耐熱水性、耐油性などの各種試験例を説明する。尚、本発明は下記の実施例及び試験例に拘束されるものではなく、本発明の技術的思想の範囲内で任意の変形をなし得ることは勿論である。
【００２７】
本発明の食品容器の熱水、油分などに対する耐久性を試験する場合、試験効率の見地から、シート状の紙にゼイン溶液などを被覆したものを試料とするとともに、上記シート状の被覆紙に折り目を付けた後に、耐水性、耐油性などを調べることにより、便宜上、しわ寄せ成形した食品容器の耐クラック性の試験例に擬制した。
《ゼイン被覆紙の耐水性、耐油性試験例》
ゼイン(ツェイン２０ＬＳ；グリコ栄養食品社製)を様々の重量比で９０％エタノールに溶解させることにより、濃度を変化させたゼインのエタノール溶液を複数種調製し、坪量１５０ｇ／ｍ2の紙にこのゼイン溶液を塗布して、単位面積当たりの付着量の異なる各種のゼイン被覆紙を製造し、これらを実施例１〜７及び比較例１〜２とした。
但し、前述したように、ゼインの付着量はゼイン溶液全体の付着量を指すのではなく、ゼイン溶液中に含有される固形分としてのゼインの値である(以下の試験例も同様である)。
当該付着量と実施例、比較例との関係は次の通りである。
実施例Ｎｏ． ゼイン溶液の付着量
比較例１ ０.１ｇ／ｍ2
比較例２ ０.３ｇ／ｍ2
実施例１ １.０ｇ／ｍ2
実施例２ ３.０ｇ／ｍ2
実施例３ ５.０ｇ／ｍ2
実施例４ １０.０ｇ／ｍ2
実施例５ １５.０ｇ／ｍ2
実施例６ ２０.０ｇ／ｍ2
実施例７ ３０.０ｇ／ｍ2
【００２８】
ゼイン付着量を変化させた紙に、水、常温の油脂分、水と油脂の混合液をスポイドで０.２ｃｃ程度夫々滴下して、１時間後の液体の浸透度合により、各被覆紙の耐水性、耐油性を調べた。
ちなみに、水は９０℃の熱水で試験を行い、油脂分と混合液の各試験は常温で行った。上記油脂には市販のサラダ油を採用した。また、各種食品には水分と油分が共に含有されることが多い点に鑑みて、水と油脂の混合液を試験項目に追加したものであり、具体的には、当該混合液は可食性界面活性剤であるショ糖脂肪酸エステルの存在下で、水／サラダ油＝９０／１０の重量比で水とサラダ油を混合したエマルションである。
また、上記耐水性、耐油性試験の評価基準は次の通りである。
○：被覆紙上に液体の浸透が全く観察されなかった。
△：被覆紙上にごく薄く液体が浸透し始めた。
×：被覆紙の表面積の５０％以上に液体が浸透して、シミを形成した。
【００２９】
下表はその試験結果である。
上表を見ると、ゼインの付着量が０.３ｇ／ｍ2以下である比較例１〜２では耐水性は確保されたが、耐油性に乏しいことが判った。
これに対して、ゼインの付着量が１.０ｇ／ｍ2である実施例１では、熱水、水／油脂の混合液に対する耐久性は確保できたが、耐油性は△であった。しかし、この耐油性は１時間後の油分の浸透性を基準としたものであり、２０分経過時点では浸透が認められなかったことから、概ね実用水準をクリアしているものと思われる。
ゼインの付着量が３.０ｇ／ｍ2以上の実施例２〜７では、耐水性、耐油性共に(即ち、全ての液体に対する耐久性は)○の評価であった。
【００３１】
《ゼイン被覆紙のクラック耐性試験例》
上記実施例１〜７及び比較例１〜２の被覆紙を縦・横に折り畳んで十字状に折り目を付け、前記試験例と同様に９０℃の熱水を滴下して、１時間後の水の漏洩の有無を調べた。
一方、ゼイン溶液と比較する見地から、シェラック(パールＮ８１１；岐阜セラック製造所製)のエタノール溶液を用意し、ゼイン溶液に対応した付着量でシェラック溶液を紙に塗布した後、これを十字状に折り畳んで、同様の漏洩試験を行った。
上記試験の評価基準は次の通りである。
○：被覆紙の折り目周辺からの水の漏洩、或は浸透は全く観察されず、クラック耐性があった。
×：被覆紙の折り目周辺から水が漏れて、クラック耐性がなかった。
【００３２】
下表はその試験結果である。
上表を見ると、シェラック被覆紙では、０.１〜０.３ｇ／ｍ2の少量の付着量の場合だけ紙の折り目からの水の浸透はなかったが、付着量が１.０ｇ／ｍ2以上に増すと、水の漏洩があり、クラック耐性がないことが判った。前述したように、シェラック皮膜は硬いために、被覆紙のストレスがかかった部位にクラックが生じ易いという弊害があるが、上記試験結果はこれを裏付けることになった。
これに対して、実施例１〜７のゼイン被覆紙は、共に折り目から水の浸透はなく、クラック耐性にも優れることが明らかになった。特に、ゼインの付着量を２０〜３０ｇ／ｍ2に増量した実施例６〜７の場合にも、良好なクラック耐性を示したことは注目に値する。
【００３４】
《ゼインとシェラックの積層被覆紙及び混合被覆紙の耐油性試験例》
上記ゼイン単独の被覆紙に替えて、紙表面にシェラックとゼインを順番に積層被覆した紙、或はゼインとシェラックの混合液を被覆した紙を夫々用いて、耐油性試験を行った。尚、耐熱水性試験は、上記付着量を変化させたゼイン被覆紙の場合に全て良好な結果を示したので、本試験では省略した。
先ず、ゼインを９０％エタノールに溶解して１５重量％溶液を調製するとともに、シェラックを同エタノールに溶解して５０重量％溶液を調製した。次いで、紙表面に５０重量％のシェラック溶液を塗布し、さらに、その上面に１５重量％のゼイン溶液を塗布して、(紙側)シェラック／ゼイン(外側)の積層被覆紙を製造し、実施例８とした。
上記塗布処理は、コーターを用いてシェラック溶液とゼイン溶液を夫々１回づつ印刷する方式により行った(従って、積層被覆紙全体では、２回印刷である)。ゼイン溶液又はシェラック溶液の１回の塗布量は夫々１０ｇ／ｍ2程度に調整した。但し、本試験例の塗布量は、ゼイン溶液中のゼイン又はシェラック溶液中のシェラックの含有量ではなく、ゼイン溶液又はシェラック溶液全体の量を示す。また、１５重量％ゼイン溶液／５０重量％シェラック溶液＝３／７の重量比でゼインとシェラックを混合して、固形分としてのゼインとシェラックの割合がゼイン５０重量％以下／シェラック５０重量％以上である混合液を調製し、この混合液を紙に１回印刷で塗布し、ゼインとシェラックの混合液の被覆紙を製造し、比較例３とした。当該混合液の塗布量は１０ｇ／ｍ2程度に調整した。
また、シェラックの５０重量％溶液を１０ｇ／ｍ2程度の塗布量で１回印刷したシェラック被覆紙を比較例４とした。
次いで、上記実施例８及び比較例３〜４の各被覆紙をそのまま、或は、十字状に折り畳んで、スポイドで０.２ｃｃ程度のサラダ油を各被覆紙に滴下して、油脂の浸透度合の経時変化を調べた。
当該試験の評価基準は次の通りである。
○：被覆紙上に油分の浸透が全く観察されなかった。
△：被覆紙上にごく薄く油分が浸透し始めた。
×：被覆紙の表面積の５０％以上に油分が浸透して、広くシミを形成した。
【００３５】
下表はその試験結果である。
上表を見ると、折り目がない場合には、実施例８、比較例３〜４共に３時間経過時点でも良好な耐油性を示した。
折り目を付けた場合、ゼイン／シェラックの混合被覆紙である比較例３は１０分後には油分が浸透しそうな兆候が現れ、３０分後には油分が浸透した。また、シェラックの単独被覆紙である比較例４では、３０分後には油分が浸透した。
これに対して、ゼイン／シェラックの積層被覆紙である実施例８では、溶液塗布量が比較例３〜４より多いという事情もあるが、３０分経過時点までは○の評価であり、１時間後にようやく油分が浸透しそうな兆候が現れ、３時間後には油分が浸透したが、概ね実用水準をクリアしていた。従って、ゼイン／シェラックの積層被覆紙は、シートの状態での耐油性のみならず、クラック耐性をも兼備することが明らかになった。
【００３７】
《ゼイン／シェラックの混合率の変化に伴う当該混合被覆紙の耐油性試験》
上記試験例のゼイン／シェラックの混合被覆紙は折り目を付けた場合の耐油性の評価が不充分であったため、ゼインとシェラックの割合を変化させた混合液を紙に塗布して、１時間後の耐油性を試験した。
即ち、ゼインを９０％エタノールに溶解してゼインの１５重量％溶液を調製し、同じくシェラックを９０％エタノールに溶解してシェラックの１５重量％溶液を調製した。
このゼイン溶液とシェラック溶液を次に示す割合で混合し、この混合液を紙にコーターで２回印刷して被覆紙を製造し、固形分としてのゼインの含有率が５０重量％以上のものを実施例９〜１１とし、５０重量％より低いものを比較例５〜６とした。
１回の塗布量を５ｇ／ｍ2程度に調整し、２回の合計量を１０ｇ／ｍ2程度とした。但し、本試験例の塗布量も、前記試験例と同様に、ゼイン溶液中のゼイン又はシェラック溶液中のシェラックの含有量ではなく、ゼイン溶液又はシェラック溶液全体の量を示す。
試験の評価基準は、上記耐油性試験例と同様とした。
【００３８】
下表はその試験結果を示す。
【００３９】
《被覆紙の耐熱油性試験例》
上述の耐油性試験はいずれも常温で被覆紙に油を滴下した場合の浸透度合を調べたものである。
そこで、前述の試験例と同様の条件で、被覆紙に大豆油を滴下し、この被覆紙を３分間レンジで加熱した後、直ちに被覆紙を取り出して油分の浸透度合を調べることにより、各被覆紙の耐熱油性試験を行った。
その結果、前述の各種試験に用いた実施例の被覆紙、即ち、ゼインの単独被覆紙である実施例１〜７、ゼイン／シェラックの積層被覆紙である実施例８、或は、ゼイン／シェラックの混合被覆紙である実施例９〜１１では、いずれも油分は浸透しなかった。このため、本発明の食品容器は常温での耐油性試験と同様に、熱油に対しても優れた耐久性を示したことから、例えば、チキンナゲット、炒麺、ハンバーグ、グラタンなどの油分の多い料理に対しても、レンジ調理用食品容器として高い実用性を備えていることが推測できた。
【００４０】
《各種冷凍食品のレンジ調理試験例》
そこで、ゼイン被覆紙及びゼイン／シェラック積層被覆紙を食品容器に夫々成形し、この食品容器に各種の冷凍食品を収容して、レンジ調理した際の耐油性、耐水性などを調べた。
先ず、ゼインを９０％エタノール溶液に溶解してゼイン溶液を調製するとともに、坪量２５０ｇ／ｍ2の紙にコーターを用いて２回印刷方式により上記ゼイン溶液を付着量１０ｇ／ｍ2の条件で片面被覆した後、アルミニウム用しわ寄せ成形機をこのゼイン被覆紙に転用して、食品容器を成形した。具体的には、ゼイン被覆面が収容面になる状態で、この被覆紙を上記成形機にかけて１００℃でしわ寄せ成形を行って、鍔付き楕円皿状の食品容器を製造し、これを実施例１２とした。
また、シェラックを９０％エタノール溶液に溶解してシェラック溶液を調製して、坪量２５０ｇ／ｍ2の紙にシェラック溶液を付着量５ｇ／ｍ2の条件で、さらにその上面にゼイン溶液を付着量５ｇ／ｍ2の条件で夫々コーターを用いて２層状に片面被覆した後、ゼイン／シェラック積層面が収容面になる状態で上記紙用成形機にかけて１００℃でしわ寄せ成形して、鍔付き楕円皿状の食品容器を製造し、実施例１３とした。
次いで、上記実施例１２〜１３の食品容器に市販の各種冷凍食品を収容して、レンジ(600KW)で加熱調理した後、直ちに取り出して観察したところ、次の結果を得た。
但し、本試験例の付着量は、ゼイン溶液又はシェラック溶液中に含有されるゼイン又はシェラックの付着量を指す。
【００４１】
先ず、チキンナゲットを約１分間加熱した場合、実施例１２では食品容器への浸透は認められず、実施例１３では斑点状の浸透部分が認められたが、実用水準をクリアしていた。
ハンバーグを約２分１０秒加熱した場合、実施例１２、１３共に斑点状の浸透が認められたが、実用水準をクリアしていた。炒麺を約１分４０秒加熱した場合も、同様の結果であった。
これらの結果から、本発明の食品容器は、レンジ調理によっても充分な保形性を持続するとともに、油分の多い冷凍食品をレンジ調理する場合に適用しても、充分な耐油性を保持することが確認できた。また、本試験例では、ゼイン或はゼイン／シェラック被覆紙を皿状にしわ寄せ成形したが、当該成形に伴ってストレスが負荷された場合でも、クラック耐性を充分に備えていることも明らかになった。
一方、鯖の煮付けを約２分１０秒加熱した場合、実施例１３は浸透跡が認められず、実施例１２はわずかに１箇所ピンポイントで浸透跡が認められただけであった。これにより、水分の多い食品に本発明の食品容器を適用しても、優れた耐水性を具備することが明らかになった。
【００４２】
《ゼイン被覆紙の生分解性試験例》
坪量２５０ｇ／ｍ2の紙に付着量１０ｇ／ｍ2の条件でゼインを塗布して４ｃｍ平方のゼイン被覆紙を製造し、このゼイン被覆紙を３枚土壌中に埋めて、時々水を与える条件で経時変化を調べて、生分解性試験を行った。また、ゼインを被覆しない紙だけのものを比較例として、やはり３枚土壌中に埋めた。
ゼイン被覆紙では、１カ月経過した時点で各試料共に約１／３〜１／２が分解しており、２カ月後には３枚共完全に分解されていた。これに対して、比較例では、２カ月経過時点で少し分解されずに残っていた。
この試験結果によると、ゼイン被覆紙は紙単独品より、生分解性速度が速いことが判り、これは、土壌中の微生物にとってゼインが良好な栄養源になり、効率良く分解されたためと思われる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a biodegradable food container having hot water resistance and oil resistance, and can be cooked in a microwave oven, oven, hot water, etc. while containing the food, is not required to be incinerated, and is directly in the soil. Provide a product that can be easily disposed of.
[0002]
BACKGROUND OF THE INVENTION
For example, cup noodle containers are made of synthetic resin such as polystyrene, polypropylene, polyester, or laminated paper such as polyethylene, and because synthetic resin-based adhesives and adhesives are also used for bonding containers, There is a risk of environmental pollution such as dioxin if burned. In addition, recently, it has also been pointed out that trace amounts of environmental hormones such as styrene monomer may be dissolved from the container.
On the other hand, frozen food containers such as gratin, curry, chicken nugget, hamburger, meat potato, etc. are often made of aluminum foil or synthetic resin. From the standpoint of reducing the amount of garbage, there is an increasing demand for natural materials that can be decomposed by microorganisms in the soil without burning.
[0003]
In order to utilize natural materials for food containers, moldability is necessary.
Examples of the natural material having moldability include shellac, chitosan, and zein.
However, since shellac promotes polymerization even at room temperature and has a melting point of around 80 ° C., when applied to a cup noodle container or the like, there is a problem in hot water resistance during cooking.
In addition, since the shellac film is hard, if it is bent or creased into a dish shape, cracks are likely to occur in the stressed part, and when food is contained, the oil content contained in the food from this cracked part There is also a problem that it soaks. In order to avoid this, it is conceivable to mix a plasticizer such as glycerin. However, when hot water cooking is performed using a molded container, the plasticizer may be eluted. In addition, when 3% or more of the plasticizer is mixed, there is a problem that the oil resistance of the shellac film itself is lowered.
On the other hand, the chitosan film is softer than shellac, but it needs to be neutralized with alkali for film formation, and the pH adjustment treatment is complicated.
On the other hand, zein is not easily broken by stress during molding, and there is no complicated pH adjustment.
[0004]
[Prior art]
The prior art of a molded container using zein is as follows.
(1) Prior art 1 (Japanese Patent Laid-Open No. 10-295338)
A range heating compatible container in which an edible container made of wheat flour, starch, soybean protein or the like is coated with zein or a range heating compatible container in which zein is directly added to the edible container is disclosed. In the latter container, for example, corn gluten containing about 60% zein is used as a food material. If the amount of zein in the whole food material is within the proper range, corn is not added without newly adding zein. Also included is forming the container with gluten.
[0005]
(2) Prior art 2 (Japanese Patent Laid-Open No. 6-234869)
A zein solution in which zein is dispersed in an aqueous acetone solution having a concentration of 65 to 75 v / v% is applied to the surface of biodegradable equipment such as monaca peel, and the equipment is heated in an atmosphere with a relative humidity of 85% or less. A method for producing a device having a practical water-resistant zein thin film by drying at a start temperature of 55 ° C. or lower is disclosed.
[0006]
[Problems to be solved by the invention]
In both of the prior arts 1 and 2, an edible container is coated with a zein film, or zein is integrally contained in the container, and the entire container is edible.
For this reason, when eating food, the container is also eaten at the same time, and there is an advantage that waste does not come out, but on the other hand, for example, the technique is used for containers for cup noodles, gratin, stew, etc. When it is applied to containers for frozen foods, it is a big problem that the strength becomes insufficient in terms of shape retention during cooking.
[0007]
The present invention is to develop a food container that has sufficient shape retention strength, hot water resistance and oil resistance, and has biodegradability and is effective in preventing environmental pollution and reducing garbage. And
[0008]
[Problems to be solved by the invention]
When the present inventors applied or impregnated a zein-containing liquid with a predetermined adhesion amount into a packaging container made of paper, the fiber layer of the paper can be smoothly coated without causing cracks. The food container was found to be capable of combining sufficient shape retention strength, hot water resistance and oil resistance while being entirely biodegradable, thus completing the present invention.
[0009]
That is, the present invention 1 is a packaging container capable of containing food molded from paper,
While applying or impregnating a zein solution on at least the inner wall side facing the accommodation space of the packaging container to form a zein film on the inner wall surface,
The amount of zein adhered to the paper constituting the packaging container as a solid content is 1.0 to 35 g / m.2It is a biodegradable food container having hot water resistance and oil resistance.
[0010]
The present invention 2 forms a laminated film of zein and shellac instead of the zein film of the present invention 1, and
The total amount of zein and shellac attached to the paper constituting the packaging container is 1.0 to 35 g / m.2It is a biodegradable food container having hot water resistance and oil resistance.
[0011]
Invention 3 uses, instead of the zein liquid of Invention 1 above, a liquid comprising a mixture of zein and shellac in a ratio of zein 50 wt% or more / shellac 50 wt% or less,
The adhering amount of the mixture to the paper constituting the packaging container is 1.0 to 35 g / m.2It is a biodegradable food container having hot water resistance and oil resistance.
[0012]
Invention 4 is a hot water-resistant water characterized in that the packaging container according to any one of Inventions 1 to 3 is a deep dish-shaped or cup-shaped container formed by integrally forming sheet-like paper by a folding method or a wrinkling method. And a biodegradable food container having oil resistance.
[0013]
A fifth aspect of the present invention is the method according to any one of the first to fourth aspects of the present invention, wherein a release agent is coated on a zein film on at least the inner wall side of the packaging container, a laminated film of zein and shellac, or a mixed film of zein and shellac. The biodegradable food container having hot water resistance and oil resistance according to any one of claims 1 to 4.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
The present invention is a food container based on paper, specifically, firstly, a container in which this paper is coated with zein, secondly, a container in which zein and shellac are laminated on paper, and thirdly, A container coated with a mixture of zein and shellac on paper.
The paper of the present invention is a broad concept including paper or non-woven fabric obtained by wet-making a fiber composition. Non-wood fiber pulp such as NBKP, LBKP and other wood pulp, deinked pulp, linter pulp, hemp, kenaf, bagasse, esparto grass, straw, etc. Recycled fibers such as rayon, cupra, and acetate.
On the other hand, ordinary nonwoven fabrics are made of thermoplastic synthetic fibers such as polyolefin fibers, polyester fibers, and polyamide fibers by a method such as spunbond, thermal bond, melt blow, etc., but the food container of the present invention has biodegradability. It is necessary. For this reason, the nonwoven fabric used for the container is not a nonwoven fabric made of such a thermoplastic synthetic fiber, but a high-pressure water column flow is ejected toward a sheet-like material wet-made with the natural or recycled fiber composition. It is preferable to adopt a hydroentangled nonwoven fabric that is made by entanglement and integration of the fibers of the fiber composition.
[0015]
The food container is formed by integrally forming a sheet of paper (papermaking or non-woven fabric) into a container by a folding method or a wrinkle method (see the present invention 4), or by using a natural substance-based adhesive such as a polysaccharide. In addition to forming a container by bonding sheet-like paper, it may be formed by a known method. The folding method is a general paper container manufacturing method in which a development view of paper is folded and formed into a container. The wrinkling method is a method in which a mold heated to 100 ° C. or higher is pressed against a sheet of paper to form a container shape (that is, deep drawing).
The shape of the food container can be any shape such as a shallow bottom tray shape or a deep bottom cup shape.
Further, when hot pressing or the like is performed on the paper surface, rough unevenness due to fibers on the paper surface is reduced, and the coating efficiency of a zein solution, a zein / shellac mixed solution, or the like is increased.
[0016]
In the zein-coated container of the present invention 1, for example, first, zein is dissolved in 70-90% ethanol, and the packaging container is immersed in the ethanol solution of zein and impregnated, or with a brush or the like. The zein solution is applied to a container.
In the above impregnation or coating treatment, zein can be more evenly attached to the fiber surface of the paper by repeating the treatment a plurality of times than when treating only once even when the amount of adhesion is the same.
The concentration of the zein solution is preferably about 10 to 20% by weight. The zein solution normally suppresses the extent that the thicker one penetrates into the fiber of the paper, so that it can stay on the paper surface and form a zein film more smoothly.
It is necessary to impregnate or apply the zein solution to the food container at least on the inner wall side facing the accommodation space of the food container, and therefore impregnate or apply both the inner wall side and the outer wall side of the packaging container. A double-sided (that is, the entire surface of the container) coating method may be used, or a single-sided coating method in which only the inner wall side is impregnated or coated may be used.
[0017]
The food container of the present invention 2 is a container in which zein and shellac are laminated and coated instead of the zein of the present invention 1 alone.
The shellac solution is applied or impregnated in the same manner as the zein solution. As the shellac liquid, an ethanol solution of shellac is generally used, and the concentration is preferably about 5 to 50% by weight.
As mentioned above, the melting point of shellac is around 80 ° C. For example, in order to wrinkle and form the paper, it is necessary to perform heat molding at around 100 ° C. or higher, so a mold is formed on the shellac coating surface. Pressing may cause heat fusion.
Accordingly, it is preferable to coat the outermost film with a zein film as the laminated film of zein and shellac applied on the surface of the paper packaging container.
Specifically, the following laminated films (1) to (2) are suitable, but the laminated film (3) is not excluded.
(1) (Paper side) Shellac film / Zein film (Outside)
(2) (Paper side) Zein film / shellac film / Zein film (outside)
(3) (Paper side) Zein film / shellac film (outside)
[0018]
The food container of the present invention 3 is a container in which zein and shellac are mixed and coated (that is, a mixture of zein and shellac is coated) instead of the container in which the zein and shellac of the present invention 2 are laminated and coated.
In the case of the mixture of zein and shellac, the mixing ratio of zein / shellac is 50% by weight or more of zein / 50% by weight or less of shellac, preferably 70% by weight or more of zein / 30% by weight or less of shellac.
The mixing of shellac contributes to cost reduction. However, when the shellac content is increased to 50% by weight or more, as described above, the film hardness becomes too hard and cracks may occur. In particular, if the mixture is impregnated or applied to a sheet of paper and bent or creased, it tends to crack, so care must be taken in the mixing ratio.
[0019]
In the zein single coating of the present invention 1, a zein solution is applied in a layer coating method of the zein and shellac of the present invention 2, and in the mixed coating of the present invention 3, a mixed solution of zein and shellac is applied. In the present invention 1, for example, in the present invention 1, the attached amount does not mean the amount of the entire zein solution used, but as a solid content remaining after evaporation of a solvent such as ethanol. It is the amount of zein (that is, the content of zein in the solution), and in the present inventions 2-3, it is the total amount of zein and shellac as solids.
Specifically, the adhesion amount is 1.0 to 35 g / m.2And preferably 10 to 20 g / m2It is. The adhesion amount is 1.0 g / m2If it is less, the oil resistance may decrease. Conversely, 35 g / m2When the container is exceeded, cracks are likely to occur when the container is bent, and the liquid may permeate from the cracks, which may reduce the water resistance and oil resistance.
Further, in the food container of the present invention 2 with the laminated coating of zein and shellac or the mixed coating of the present invention 3, the impregnation or coating treatment to the food container is at least a food container as in the present invention 1. It is enough to apply to the inner wall facing the accommodation space.
Furthermore, when applying or impregnating a predetermined adhesion amount, it may be processed once, but from the viewpoint of ensuring the uniformity, smoothness, etc. of the coating film, it is better to perform the coating process in multiple times. What is preferable is the same as in the first aspect of the present invention.
[0020]
The mold release agent of the present invention 5 is edible surfactant, vegetable oil, silicone oil, lard, lard, etc. Examples of edible surfactant include glycerin fatty acid ester, sucrose fatty acid ester, sorbitan fatty acid ester, lecithin. , Chitosan and the like. Examples of vegetable oils include soybean oil, palm oil, safflower oil, nuka oil and olive oil.
Since the release agent is for smoothly peeling cooked food from a food container or preventing paper fibers constituting the container from biting into the food, the present invention coated on the food container The release agent may be coated on at least the film on the inner wall side of the food container among the zein film 1, the laminated film of zein and shellac of the present invention 2, or the mixed film of the present invention 3.
[0021]
The shape of the food container may be any shape including a shallow dish tray and a deep dish cup.
The food container of the present invention is a container containing frozen foods such as gratin, doria, curry, chicken nugget, boiled salmon, meat potato, hamburger, fried noodles, shmai, gyoza, cup noodle container, pudding, jelly The container can be applied as an arbitrary food container.
Therefore, the food container can be used for cooking with a microwave oven, oven, etc. while containing frozen food such as gratin, pouring hot water like cup noodles, or pudding, etc. Filling with hot sol solution and cooling can be mentioned, and even under the cooking conditions, the food container of the present invention can have practical durability (specifically, shape retention). .
[0022]
【The invention's effect】
(1) A food container in which a zein film, a laminated film of zein and shellac, or a mixed film of zein and shellac is coated with an appropriate amount on a packaging container made of paper. Even if frozen food such as food is stored and cooked in a microwave oven, the oil content and moisture of the food do not penetrate into the paper, and the shape retention of the container can be reliably maintained. Also, when used in a container for cup noodles, hot water is prevented from penetrating into the paper, and the shape retaining property can be sufficiently maintained.
That is, the food container of the present invention is durable in range cooking etc. regardless of the type of foods with high oil content such as chicken nuggets and gratin, or foods with high water content such as boiled salmon and meat potatoes. Since it can be secured sufficiently, it is suitable as a substitute for a conventional container made of synthetic resin such as polystyrene, polypropylene, polyester or laminated paper such as polyethylene.
Moreover, as a disposal method after cooking in a microwave oven, oven, hot water, etc., unlike conventional synthetic resin food containers, it can be easily decomposed by microorganisms even if discarded in the soil as it is. Can be effectively preserved. Moreover, since it is not necessary to incinerate like the said synthetic resin container, it is useful also for reduction of the amount of garbage.
In addition, the food container of the present invention maintains good shape retention for foods with a lot of oil and moisture, and therefore foods to be eaten and eaten without cooking, such as natto, salad, various side dishes, pudding, or Is also suitable as a container for various beverages. In addition, the container of the present invention having biodegradability can be discarded as it is in the soil as food waste after eating and drinking, and since there is no risk of dioxins being generated during combustion, it is discarded compared to containers made of synthetic resin. Processing costs can be reduced.
[0023]
(2) In the food container coated with zein according to the first aspect of the present invention, the film hardness is softer than that of a single-use film such as shellac, as shown in the following test example, and sheet-like paper is folded, or There is no risk of cracking even if the container is formed integrally with the wrinkle-drawing method. For this reason, when food is contained, it is possible to smoothly prevent the oil content and moisture of the food from permeating through cracks generated in the container and weakening the shape retention of the container. Further, as in the case of forming a film with chitosan, complicated labor such as pH adjustment is not required.
[0024]
(3) The laminated film of zein and shellac of the present invention 2 or the mixed film of the present invention 3 exhibits hot water resistance and oil resistance similar to those of a zein single film, as shown in the following test examples. Compared to shellac single-use film, the film hardness is soft and cracks can be effectively prevented at a practical level.
Moreover, compared with the food container which single-coated the zein of this invention 1, it is effective in a cost reduction by the part which laminated | stacked or mixed cheap shellac.
[0025]
(4) In the present invention 5, since a release agent such as fat is coated on a zein film, a laminated film of zein and shellac, or a mixed film, the cooked food can be easily peeled from the container.
For example, when used as a container such as pudding or jelly, gelled pudding can be smoothly taken out from the container when these hot sol liquids are put in the container and cooled.
[0026]
【Example】
Hereinafter, various test examples such as hot water resistance and oil resistance associated with changes in the amount of zein solution and the presence / absence of a bending process will be described using paper coated with zein. It should be noted that the present invention is not limited to the following examples and test examples, and can of course be modified arbitrarily within the scope of the technical idea of the present invention.
[0027]
When testing the durability of the food container of the present invention against hot water, oil, etc., from the viewpoint of test efficiency, a sheet-shaped paper coated with a zein solution or the like is used as a sample, and the above-mentioned sheet-shaped coated paper is used. After making the crease, the water resistance, oil resistance, and the like were examined, and for the sake of convenience, a test example of the crack resistance of the food container formed by wrinkling was simulated.
<Water and oil resistance test example of zein-coated paper>
By dissolving zein (Zein 20LS; manufactured by Glico Nutrition Foods, Inc.) in 90% ethanol at various weight ratios, a plurality of zein ethanol solutions having different concentrations were prepared, and the basis weight was 150 g / m.2This zein solution was applied to a sheet of paper to produce various types of zein-coated paper having different adhesion amounts per unit area, and these were designated as Examples 1 to 7 and Comparative Examples 1 and 2.
However, as described above, the attached amount of zein does not indicate the attached amount of the entire zein solution, but is the value of zein as a solid content contained in the zein solution (the same applies to the following test examples). .
The relationship between the adhesion amount and the examples and comparative examples is as follows.
Example No. Amount of zein solution deposited
Comparative Example 1 0.1 g / m2
Comparative Example 2 0.3 g / m2
Example 1 1.0 g / m2
Example 2 3.0 g / m2
Example 3 5.0 g / m2
Example 4 10.0 g / m2
Example 5 15.0 g / m2
Example 6 20.0 g / m2
Example 7 30.0 g / m2
[0028]
Water, oil and fat at room temperature, and a mixture of water and oil are dropped about 0.2 cc with a dropper on paper with varying zein adhesion, and the water resistance of each coated paper is determined by the degree of penetration of the liquid one hour later. And oil resistance were examined.
By the way, water was tested with hot water of 90 ° C., and each test of the oil and fat and the mixed solution was performed at room temperature. Commercially available salad oil was adopted as the oil. In view of the fact that various foods often contain both water and oil, a mixed liquid of water and fat is added to the test items. Specifically, the mixed liquid has an edible interface. It is an emulsion in which water and salad oil are mixed at a weight ratio of water / salad oil = 90/10 in the presence of sucrose fatty acid ester as an active agent.
The evaluation criteria for the water resistance and oil resistance tests are as follows.
○: No liquid permeation was observed on the coated paper.
Δ: The liquid started to penetrate very thinly on the coated paper.
X: The liquid permeated 50% or more of the surface area of the coated paper to form a spot.
[0029]
The table below shows the test results.
Looking at the table above, the amount of zein attached is 0.3 g / m.2In Comparative Examples 1 and 2 below, water resistance was ensured, but it was found that oil resistance was poor.
In contrast, the amount of zein attached was 1.0 g / m.2In Example 1, the durability against hot water and water / oil mixture could be secured, but the oil resistance was Δ. However, this oil resistance is based on the permeability of the oil after 1 hour, and no penetration was observed after 20 minutes.
The amount of zein attached is 3.0 g / m2In Examples 2 to 7 described above, both water resistance and oil resistance (that is, durability against all liquids) were evaluated as good.
[0031]
《Example of crack resistance test for zein-coated paper》
The coated papers of Examples 1 to 7 and Comparative Examples 1 and 2 were folded vertically and horizontally to create a cross-shaped crease, and hot water at 90 ° C. was added dropwise in the same manner as in the above test example, and water after 1 hour. The presence or absence of leakage was examined.
On the other hand, from the standpoint of comparison with the zein solution, an ethanol solution of shellac (Pearl N811; manufactured by Gifu Shellac Factory) was prepared, and the shellac solution was applied to the paper in an adhesion amount corresponding to the zein solution, and then this was cross-shaped. The same leak test was conducted after folding.
The evaluation criteria for the above test are as follows.
○: No leakage or penetration of water from the periphery of the crease of the coated paper was observed, and there was crack resistance.
X: Water leaked from around the crease of the coated paper, and there was no crack resistance.
[0032]
The table below shows the test results.
Looking at the table above, for shellac-coated paper, 0.1 to 0.3 g / m2Water did not permeate through the paper folds only when the amount of adhesion was small, but the adhesion amount was 1.0 g / m.2When increased above, it was found that there was water leakage and no crack resistance. As described above, since the shellac film is hard, there is a problem that cracks are likely to occur in the stressed portion of the coated paper, but the above test results support this.
On the other hand, it became clear that the zein-coated papers of Examples 1 to 7 did not penetrate water from the folds and were excellent in crack resistance. In particular, the amount of zein attached is 20-30 g / m.2It is worth noting that the good crack resistance was also exhibited in Examples 6 to 7 in which the amount was increased.
[0034]
<< Oil resistance test example of zein and shellac laminated coated paper and mixed coated paper >>
The oil resistance test was conducted using paper coated with shellac and zein in order, or paper coated with a mixed solution of zein and shellac on the paper surface in place of the zein single coated paper. The hot water resistance test was omitted in this test because it showed good results in the case of zein-coated paper with different adhesion amounts.
First, zein was dissolved in 90% ethanol to prepare a 15 wt% solution, and shellac was dissolved in the same ethanol to prepare a 50 wt% solution. Next, a 50% by weight shellac solution is applied to the paper surface, and a 15% by weight zein solution is further applied to the upper surface to produce a (paper side) shellac / zein (outside) laminated coated paper. Example 8 was adopted.
The coating process was performed by a method in which a shellac solution and a zein solution were printed once each using a coater (thus, the entire laminated coated paper is printed twice). Each application amount of zein solution or shellac solution is 10 g / m.2Adjusted to the extent. However, the coating amount of this test example indicates not the content of zein in the zein solution or shellac in the shellac solution, but the amount of the entire zein solution or shellac solution. Also, zein and shellac were mixed at a weight ratio of 15 wt% zein solution / 50 wt% shellac solution = 3/7, and the ratio of zein and shellac as a solid content was 50 wt% or less of zein / 50 wt% or more of shellac. A mixed liquid was prepared, and this mixed liquid was applied to paper once by printing to produce a coated paper of a mixed liquid of zein and shellac. The coating amount of the mixture is 10 g / m2Adjusted to the extent.
In addition, a 50 wt% solution of shellac was 10 g / m2A shellac-coated paper that was printed once with a coating amount of about was designated as Comparative Example 4.
Next, each coated paper of Example 8 and Comparative Examples 3 to 4 is folded as it is or in a cross shape, and about 0.2 cc of salad oil is dropped on each coated paper with a spoid, and the degree of penetration of fats and oils is determined. The change with time was examined.
The evaluation criteria for this test are as follows.
○: No penetration of oil was observed on the coated paper.
Δ: The oil started to penetrate very thinly on the coated paper.
X: The oil component penetrated into 50% or more of the surface area of the coated paper, and a wide spot was formed.
[0035]
The table below shows the test results.
When the above table was seen, when there was no crease, both Example 8 and Comparative Examples 3-4 showed good oil resistance even after 3 hours.
In the case of crease, Comparative Example 3 which is a mixed coated paper of zein / shellac showed signs that the oil was likely to permeate after 10 minutes, and the oil permeated after 30 minutes. In Comparative Example 4, which is a shellac single-coated paper, the oil penetrated after 30 minutes.
On the other hand, in Example 8, which is a zein / shellac laminated coated paper, there is a circumstance that the amount of the solution applied is larger than Comparative Examples 3 to 4, but the evaluation is ○ until 30 minutes have passed, and 1 hour Later, there was a sign that the oil was likely to permeate, and the oil permeated 3 hours later, but it was almost clear of the practical level. Accordingly, it has been clarified that the zein / shellac laminated coated paper has not only oil resistance in the sheet state but also crack resistance.
[0037]
<< Oil Resistance Test of the Mixed Coated Paper with Change in Zane / Shellac Mixing Ratio >>
Since the zein / shellac mixed coated paper of the above test example had insufficient evaluation of oil resistance when creased, a mixed solution in which the ratio of zein and shellac was changed was applied to the paper, and 1 hour later Were tested for oil resistance.
That is, zein was dissolved in 90% ethanol to prepare a 15% by weight solution of zein, and shellac was dissolved in 90% ethanol to prepare a 15% by weight solution of shellac.
This zein solution and shellac solution are mixed in the following proportions, and this mixed solution is printed on a paper twice with a coater to produce a coated paper, and the zein content as a solid content is 50% by weight or more. It was set as Examples 9-11, and the thing lower than 50 weight% was made into Comparative Examples 5-6.
One application amount is 5 g / m2The total amount of 2 times is adjusted to 10g / m2The degree. However, the coating amount of this test example is not the content of zein in the zein solution or the shellac in the shellac solution, but the amount of the zein solution or the entire shellac solution, as in the above test example.
The evaluation criteria of the test were the same as in the above oil resistance test example.
[0038]
The table below shows the test results.
[0039]
<Example of heat resistance test for coated paper>
All of the oil resistance tests described above were conducted by examining the degree of penetration when oil was dropped onto the coated paper at room temperature.
Therefore, under the same conditions as in the above test example, soybean oil was dropped on the coated paper, the coated paper was heated in a range for 3 minutes, and then the coated paper was immediately taken out to examine the degree of penetration of the oil. A heat oil resistance test of the paper was performed.
As a result, the coated papers of the examples used in the various tests described above, that is, Examples 1 to 7 which are zein single coated paper, Example 8 which is a laminated coated paper of zein / shellac, or zein / shellac. In Examples 9 to 11, which are mixed coated papers, no oil penetrated. For this reason, since the food container of the present invention showed excellent durability against hot oil as well as the oil resistance test at room temperature, for example, there are many oils such as chicken nuggets, fried noodles, hamburger, gratin, etc. It can be presumed that cooking is highly practical as a food container for range cooking.
[0040]
《Examples of range cooking tests for various frozen foods》
Therefore, zein-coated paper and zein / shellac laminated coated paper were each formed into a food container, and various frozen foods were accommodated in the food container, and the oil resistance and water resistance when cooked in a range were examined.
First, zein is dissolved in a 90% ethanol solution to prepare a zein solution, and the basis weight is 250 g / m.2The above zein solution was applied to the paper with a coater by a two-time printing method with an amount of 10 g / m.2After coating on one side under the above conditions, an aluminum creasing machine was diverted to this zein-coated paper to form a food container. Specifically, in a state where the zein-coated surface becomes the accommodating surface, the coated paper is subjected to wrinkle molding at 100 ° C. by using the molding machine to produce an oval dish-shaped food container with a basket, which is used in Example 12. It was.
In addition, shellac was dissolved in a 90% ethanol solution to prepare a shellac solution, and the basis weight was 250 g / m.25 g / m of shellac solution on paper2The amount of zein solution deposited on the upper surface was 5 g / m.2After coating on one side in two layers using a coater under the above conditions, the paper is machined and crumpled at 100 ° C. using the paper molding machine with the zein / shellac laminated surface as the receiving surface, and a food container in the shape of an elliptical dish with a bowl This was manufactured as Example 13.
Next, various frozen foods on the market were stored in the food containers of Examples 12 to 13, cooked in a range (600 KW), and then immediately taken out and observed. The following results were obtained.
However, the adhesion amount in this test example refers to the adhesion amount of zein or shellac contained in the zein solution or shellac solution.
[0041]
First, when the chicken nugget was heated for about 1 minute, no penetration into the food container was observed in Example 12, and a spotted penetration portion was observed in Example 13, but the practical level was cleared.
When the hamburger was heated for about 2 minutes and 10 seconds, spot-like penetration was observed in both Examples 12 and 13, but the practical level was cleared. The same result was obtained when the fried noodles were heated for about 1 minute and 40 seconds.
From these results, the food container of the present invention maintains sufficient shape retention even when cooked in a range, and retains sufficient oil resistance even when applied to cooked frozen foods rich in oil. Was confirmed. In this test example, zein or zein / shellac-coated paper was formed in a wrinkled shape, but it was also found that it had sufficient crack resistance even when stress was applied along with the forming. It was.
On the other hand, when the boiled rice was heated for about 2 minutes and 10 seconds, no penetration mark was observed in Example 13, and only a single penetration point was observed in Example 12. Thus, it was revealed that even when the food container of the present invention is applied to a food with a lot of moisture, it has excellent water resistance.
[0042]
<Example of biodegradability test for zein-coated paper>
Basis weight 250g / m210g / m on the paper2The zein was applied under the above conditions to produce a 4 cm square zein-coated paper. Three sheets of this zein-coated paper were buried in the soil, and the time-dependent change was examined under conditions where water was occasionally given, and a biodegradability test was conducted. . In addition, as a comparative example, only paper that did not cover zein was buried in the soil.
In the case of zein-coated paper, about 1/3 to 1/2 of each sample was decomposed after one month, and three sheets were completely decomposed after two months. On the other hand, in the comparative example, it remained without being decomposed for a while after two months.
The test results show that zein-coated paper has a faster biodegradation rate than paper alone, probably because zein is a good source of nutrients for microorganisms in the soil and is degraded efficiently. .
Claims (5)
少なくとも上記包装容器の収容空間に臨む内壁側にゼイン液を塗布又は含浸処理して当該内壁面上にゼインの皮膜を形成するとともに、
上記包装容器を構成する紙に対する固形分としてのゼインの付着量が１.０〜３５ｇ／ｍ2であることを特徴とする耐熱水性及び耐油性を有する生分解性食品容器。A packaging container capable of containing food molded from paper,
While applying or impregnating a zein solution on the inner wall side facing at least the housing space of the packaging container to form a zein film on the inner wall surface,
A biodegradable food container having hot water resistance and oil resistance, wherein the amount of zein attached to the paper constituting the packaging container as a solid content is 1.0 to 35 g / m 2 .
包装容器を構成する紙に対するゼイン及びシェラックの合計付着量が１.０〜３５ｇ／ｍ2であることを特徴とする耐熱水性及び耐油性を有する生分解性食品容器。In place of the zein film according to claim 1, a laminated film of zein and shellac is formed,
A biodegradable food container having hot water resistance and oil resistance, wherein the total adhesion amount of zein and shellac to the paper constituting the packaging container is 1.0 to 35 g / m 2 .
包装容器を構成する紙に対する上記混合物の付着量が１.０〜３５ｇ／ｍ2であることを特徴とする耐熱水性及び耐油性を有する生分解性食品容器。Instead of the zein liquid according to claim 1, a liquid composed of a mixture of zein and shellac in a ratio of zein 50 wt% or more / shellac 50 wt% or less is used,
A biodegradable food container having hot water resistance and oil resistance, wherein the adhesion amount of the mixture to paper constituting the packaging container is 1.0 to 35 g / m 2 .
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| JP4748725B2 (en) * | 2006-07-08 | 2011-08-17 | 日本テトラパック株式会社 | Paper packaging container and method for producing paper packaging container |
| JP5436025B2 (en) * | 2009-04-27 | 2014-03-05 | 勇 武藤 | Liquid storage container |
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| MX2021002943A (en) * | 2018-09-12 | 2021-09-23 | Greentech Global Pte Ltd | Biobased barrier coatings. |
| WO2020247355A1 (en) * | 2019-06-03 | 2020-12-10 | Board Of Trustees Of Michigan State University | Biodegradable omniphobic and high-barrier coatings, related articles, and related methods |
| CN114635307B (en) * | 2022-02-28 | 2023-03-14 | 齐鲁工业大学 | Biodegradable straw taking composite straw as raw material and preparation method thereof |
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