JP4319358B2 - Polyester resin-coated metal plate and can using the same - Google Patents
Polyester resin-coated metal plate and can using the same Download PDFInfo
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- JP4319358B2 JP4319358B2 JP2000607819A JP2000607819A JP4319358B2 JP 4319358 B2 JP4319358 B2 JP 4319358B2 JP 2000607819 A JP2000607819 A JP 2000607819A JP 2000607819 A JP2000607819 A JP 2000607819A JP 4319358 B2 JP4319358 B2 JP 4319358B2
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- polyester resin
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- 229920001225 polyester resin Polymers 0.000 title claims description 86
- 239000004645 polyester resin Substances 0.000 title claims description 86
- 229910052751 metal Inorganic materials 0.000 title claims description 68
- 239000002184 metal Substances 0.000 title claims description 68
- 229920005989 resin Polymers 0.000 claims description 59
- 239000011347 resin Substances 0.000 claims description 59
- 238000002425 crystallisation Methods 0.000 claims description 30
- 239000011248 coating agent Substances 0.000 claims description 19
- 238000000576 coating method Methods 0.000 claims description 19
- 230000008025 crystallization Effects 0.000 claims description 19
- 238000010030 laminating Methods 0.000 claims description 11
- 229910000831 Steel Inorganic materials 0.000 claims description 9
- 239000010959 steel Substances 0.000 claims description 9
- 229910000838 Al alloy Inorganic materials 0.000 claims description 7
- 239000005029 tin-free steel Substances 0.000 claims description 6
- 239000010410 layer Substances 0.000 description 44
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 17
- 238000000034 method Methods 0.000 description 17
- 229910052804 chromium Inorganic materials 0.000 description 16
- 239000011651 chromium Substances 0.000 description 16
- 239000000796 flavoring agent Substances 0.000 description 12
- 235000019634 flavors Nutrition 0.000 description 12
- 230000007797 corrosion Effects 0.000 description 11
- 238000005260 corrosion Methods 0.000 description 11
- 238000005336 cracking Methods 0.000 description 8
- 239000000853 adhesive Substances 0.000 description 7
- 238000000465 moulding Methods 0.000 description 7
- 230000001070 adhesive effect Effects 0.000 description 6
- 150000002148 esters Chemical group 0.000 description 6
- 238000002844 melting Methods 0.000 description 6
- 230000008018 melting Effects 0.000 description 6
- 239000002356 single layer Substances 0.000 description 6
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 5
- 239000004593 Epoxy Substances 0.000 description 4
- 238000010409 ironing Methods 0.000 description 4
- 239000005028 tinplate Substances 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- LLLVZDVNHNWSDS-UHFFFAOYSA-N 4-methylidene-3,5-dioxabicyclo[5.2.2]undeca-1(9),7,10-triene-2,6-dione Chemical compound C1(C2=CC=C(C(=O)OC(=C)O1)C=C2)=O LLLVZDVNHNWSDS-UHFFFAOYSA-N 0.000 description 3
- ISWSIDIOOBJBQZ-UHFFFAOYSA-N Phenol Chemical compound OC1=CC=CC=C1 ISWSIDIOOBJBQZ-UHFFFAOYSA-N 0.000 description 3
- DNIAPMSPPWPWGF-UHFFFAOYSA-N Propylene glycol Chemical compound CC(O)CO DNIAPMSPPWPWGF-UHFFFAOYSA-N 0.000 description 3
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 3
- MTHSVFCYNBDYFN-UHFFFAOYSA-N diethylene glycol Chemical compound OCCOCCO MTHSVFCYNBDYFN-UHFFFAOYSA-N 0.000 description 3
- 238000001125 extrusion Methods 0.000 description 3
- 238000007747 plating Methods 0.000 description 3
- 229920000728 polyester Polymers 0.000 description 3
- 239000011342 resin composition Substances 0.000 description 3
- QPFMBZIOSGYJDE-UHFFFAOYSA-N 1,1,2,2-tetrachloroethane Chemical compound ClC(Cl)C(Cl)Cl QPFMBZIOSGYJDE-UHFFFAOYSA-N 0.000 description 2
- LZFNKJKBRGFWDU-UHFFFAOYSA-N 3,6-dioxabicyclo[6.3.1]dodeca-1(12),8,10-triene-2,7-dione Chemical compound O=C1OCCOC(=O)C2=CC=CC1=C2 LZFNKJKBRGFWDU-UHFFFAOYSA-N 0.000 description 2
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 2
- WNLRTRBMVRJNCN-UHFFFAOYSA-N adipic acid Chemical compound OC(=O)CCCCC(O)=O WNLRTRBMVRJNCN-UHFFFAOYSA-N 0.000 description 2
- 230000032683 aging Effects 0.000 description 2
- 235000013361 beverage Nutrition 0.000 description 2
- 229920001577 copolymer Polymers 0.000 description 2
- QQVIHTHCMHWDBS-UHFFFAOYSA-N isophthalic acid Chemical compound OC(=O)C1=CC=CC(C(O)=O)=C1 QQVIHTHCMHWDBS-UHFFFAOYSA-N 0.000 description 2
- 238000003475 lamination Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 239000008188 pellet Substances 0.000 description 2
- 229910052698 phosphorus Inorganic materials 0.000 description 2
- 239000011574 phosphorus Substances 0.000 description 2
- 229920006267 polyester film Polymers 0.000 description 2
- 229920000139 polyethylene terephthalate Polymers 0.000 description 2
- 239000005020 polyethylene terephthalate Substances 0.000 description 2
- CXMXRPHRNRROMY-UHFFFAOYSA-N sebacic acid Chemical compound OC(=O)CCCCCCCCC(O)=O CXMXRPHRNRROMY-UHFFFAOYSA-N 0.000 description 2
- 239000000758 substrate Substances 0.000 description 2
- ARCGXLSVLAOJQL-UHFFFAOYSA-N trimellitic acid Chemical compound OC(=O)C1=CC=C(C(O)=O)C(C(O)=O)=C1 ARCGXLSVLAOJQL-UHFFFAOYSA-N 0.000 description 2
- 238000009966 trimming Methods 0.000 description 2
- WSQZNZLOZXSBHA-UHFFFAOYSA-N 3,8-dioxabicyclo[8.2.2]tetradeca-1(12),10,13-triene-2,9-dione Chemical compound O=C1OCCCCOC(=O)C2=CC=C1C=C2 WSQZNZLOZXSBHA-UHFFFAOYSA-N 0.000 description 1
- ZVSXNPBSZYQDKJ-UHFFFAOYSA-N 3,8-dioxabicyclo[8.3.1]tetradeca-1(14),10,12-triene-2,9-dione Chemical compound O=C1OCCCCOC(=O)C2=CC=CC1=C2 ZVSXNPBSZYQDKJ-UHFFFAOYSA-N 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 1
- JOYRKODLDBILNP-UHFFFAOYSA-N Ethyl urethane Chemical compound CCOC(N)=O JOYRKODLDBILNP-UHFFFAOYSA-N 0.000 description 1
- 239000004952 Polyamide Substances 0.000 description 1
- WGLPBDUCMAPZCE-UHFFFAOYSA-N Trioxochromium Chemical compound O=[Cr](=O)=O WGLPBDUCMAPZCE-UHFFFAOYSA-N 0.000 description 1
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Chemical compound NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 238000010306 acid treatment Methods 0.000 description 1
- 239000001361 adipic acid Substances 0.000 description 1
- 235000011037 adipic acid Nutrition 0.000 description 1
- 229920006127 amorphous resin Polymers 0.000 description 1
- 239000003963 antioxidant agent Substances 0.000 description 1
- 230000003078 antioxidant effect Effects 0.000 description 1
- 239000004202 carbamide Substances 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- KRVSOGSZCMJSLX-UHFFFAOYSA-L chromic acid Substances O[Cr](O)(=O)=O KRVSOGSZCMJSLX-UHFFFAOYSA-L 0.000 description 1
- 229910000423 chromium oxide Inorganic materials 0.000 description 1
- 235000013353 coffee beverage Nutrition 0.000 description 1
- 239000010960 cold rolled steel Substances 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- VEIOBOXBGYWJIT-UHFFFAOYSA-N cyclohexane;methanol Chemical compound OC.OC.C1CCCCC1 VEIOBOXBGYWJIT-UHFFFAOYSA-N 0.000 description 1
- 230000002950 deficient Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- WMYWOWFOOVUPFY-UHFFFAOYSA-L dihydroxy(dioxo)chromium;phosphoric acid Chemical compound OP(O)(O)=O.O[Cr](O)(=O)=O WMYWOWFOOVUPFY-UHFFFAOYSA-L 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- AWJWCTOOIBYHON-UHFFFAOYSA-N furo[3,4-b]pyrazine-5,7-dione Chemical compound C1=CN=C2C(=O)OC(=O)C2=N1 AWJWCTOOIBYHON-UHFFFAOYSA-N 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 229920001519 homopolymer Polymers 0.000 description 1
- BHEPBYXIRTUNPN-UHFFFAOYSA-N hydridophosphorus(.) (triplet) Chemical compound [PH] BHEPBYXIRTUNPN-UHFFFAOYSA-N 0.000 description 1
- 230000001771 impaired effect Effects 0.000 description 1
- 239000000314 lubricant Substances 0.000 description 1
- 239000000155 melt Substances 0.000 description 1
- 239000011259 mixed solution Substances 0.000 description 1
- KYTZHLUVELPASH-UHFFFAOYSA-N naphthalene-1,2-dicarboxylic acid Chemical compound C1=CC=CC2=C(C(O)=O)C(C(=O)O)=CC=C21 KYTZHLUVELPASH-UHFFFAOYSA-N 0.000 description 1
- SLCVBVWXLSEKPL-UHFFFAOYSA-N neopentyl glycol Chemical compound OCC(C)(C)CO SLCVBVWXLSEKPL-UHFFFAOYSA-N 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 239000003973 paint Substances 0.000 description 1
- 229920002647 polyamide Polymers 0.000 description 1
- -1 polyethylene terephthalate Polymers 0.000 description 1
- 229920000098 polyolefin Polymers 0.000 description 1
- 238000004080 punching Methods 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 239000003381 stabilizer Substances 0.000 description 1
- 238000004381 surface treatment Methods 0.000 description 1
- 239000004408 titanium dioxide Substances 0.000 description 1
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D7/00—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials
- B05D7/14—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials to metal, e.g. car bodies
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B15/00—Layered products comprising a layer of metal
- B32B15/04—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material
- B32B15/08—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D2701/00—Coatings being able to withstand changes in the shape of the substrate or to withstand welding
- B05D2701/10—Coatings being able to withstand changes in the shape of the substrate or to withstand welding withstanding draw and redraw process, punching
Landscapes
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Wood Science & Technology (AREA)
- Laminated Bodies (AREA)
Description
【技術分野】
【０００１】
本発明は、ポリエステル樹脂被覆金属板、およびそれを用いた缶に関する。より詳細には、成形性、耐食性、および内容物のフレーバー性（風味の不変性）に優れた、特に飲料缶に適用するポリエステル樹脂被覆金属板、およびそれに深絞り加工等を施してなる缶に関する。
【背景技術】
【０００２】
近年、ポリエステル樹脂を２軸方向に延伸した配向フィルムを金属板に被覆し、絞り比や缶側壁部の減厚率が高い薄肉化絞り加工等の厳しい成形加工方法を用いて製缶した缶が、主に飲料缶の用途で用いられている。この２軸配向ポリエステルフィルム被覆金属板を薄肉化絞り加工すると、金属板表面に被覆された樹脂フィルムが変形量の大きい加工に完全に対応できず、フィルムに微小なクラックが生じて耐食性が劣化したり、加工時にフィルムが割れて破胴し、製缶が不可能になることがあり、さらに絞り比や減厚率を高めて缶のコストダウンを図ることが極めて困難になっている。ポリエステルフィルムの２軸配向を低下もしくは無配向化させると成形加工性は向上するが、樹脂の結晶性が低下するために樹脂フィルムの水や酸素に耐する耐透過性が減少し、製缶した缶に内容物を充填して長期間経時させた場合の耐食性および内容物のフレーバー性が不良となる。
本発明は、薄肉化絞り加工のような厳しい成形加工を施してもクラックが生じたり割れたりすることがなく、加工性および耐食性に優れたポリエステル樹脂被覆金属板、およびそれを用いた内容物のフレーバー性に優れた缶を提供することを目的とする。
【発明の開示】
【０００３】
（１）本発明のポリエステル樹脂被覆金属板は、金属板の少なくとも片面に固有粘度０．６〜１．４の２層のポリエステル樹脂を被覆してなるポリエステル樹脂被覆金属板であって、
前記２層のポリエステル樹脂は、
示差走査熱分析装置（ＤＳＣ）を用いて測定した場合に、
上層とする樹脂はその半結晶化時間が８０秒未満、
下層とする樹脂はその半結晶化時間が５０秒以上、
かつ、上層の樹脂の半結晶化時間が下層の樹脂の半結晶化時間より短い、
という条件を満たす樹脂を選択して上下に積層してなる２層フィルムであることを特徴とする。
（２）本発明のポリエステル樹脂被覆金属板は、前記（１）において、ポリエステル樹脂が無配向であることを特徴とする。
（３）本発明のポリエステル樹脂被覆金属板は、前記（１）又は（２）において、金属板が、錫めっき鋼板、ティンフリースチール、アルミニウム合金板のいずれかであることを特徴とする。
（４）本発明のポリエステル樹脂被覆金属板を用いてなる缶は、前記（１）〜（３）のいずれかのポリエステル樹脂被覆金属板を用いてなることをを特徴とする。
【０００４】
本発明は、固有粘度が０．６〜１．４であり半結晶化時間が５０秒以上である単層のポリエステル樹脂、または上層が半結晶化時間が８０秒未満、下層が半結晶化時間が５０秒以上であり、両層の固有粘度が０．６〜１．４である２層のポリエステル樹脂を金属板の少なくとも片面に被覆したポリエステル樹脂被覆金属板であり、薄肉化絞り加工のような厳しい成形加工を施しても樹脂にクラックが生じたり割れたりすることがなく、優れた加工性および耐食性を示す。また本発明のポリエステル樹脂被覆金属板を用いた缶は、内容物のフレーバー性に優れている。
以下、本発明を詳細に説明する。
まず、本発明に適用するポリエステル樹脂について説明する。ポリエステル樹脂としては、エチレンテレフタレート、エチレンイソフタレート、ブチレンテレフタレート、ブチレンイソフタレートなどのエステル単位を有するものが好ましく、さらにこれらの中から選択される少なくとも１種類のエステル単位を主体とするポリエステルであることが好ましい。このとき、各エステル単位は共重合されていてもよく、さらには２種類以上の各エステル単位のホモポリマーまたは共重合ポリマーをブレンドして用いてもよい。上記以外のもので、エステル単位の酸成分として、ナフタレンジカルボン酸、アジピン酸、セバシン酸、トリメリット酸などを用いたものなど、またエステル単位のアルコール成分として、プロピレングリコール、ジエチレングリコール、ネオペンチルグリコール、シクロヘキサンジメタノール、ペンタエチスリトールなどを用いたものを用いてもよい。
本発明においては後記するように無配向のポリエステル樹脂を用いることを前提としており、ポリエステル樹脂を金属板に被覆する作業において樹脂が切れたり、ポリエステル樹脂を被覆した金属板に薄肉化絞り加工のような厳しい成形加工を施しても樹脂が削れたり疵付いたりすることがなく、またクラックが生じたり割れたり、さらに剥離することがないようにするため、樹脂の固有粘度を高め、樹脂を強化させる必要がある。このため、上記のポリエステル樹脂の固有粘度を０．６〜１．４の範囲とすることが好ましく、０．８〜１．２の範囲とすることがより好ましい。固有粘度が０．６未満のポリエステル樹脂を用いた場合は樹脂の強度が極端に低下し、本発明の目的とする、薄肉化絞り加工缶に適用できない。一方、樹脂の固有粘度が１．４を超えると樹脂を加熱溶融させた際の溶融粘度が極端に高くなり、ポリエステル樹脂を金属板に被覆する作業が極めて困難になる。
また、上記のポリエステル樹脂を単層で金属板に被覆する場合は、示差走査熱分析装置（ＤＳＣ）を用いて測定したポリエステル樹脂の半結晶化時間が５０秒以上であることが好ましい。本発明でいう半結晶化時間は、以下のように定義する。すなわち、ポリエステル樹脂被覆金属板から剥離した一定重量のポリエステル樹脂を示差走査熱分析装置（ＤＳＣ）を用いて９０℃／分の昇温速度でポリエステル樹脂の融解温度以上の２９０℃まで加熱し溶融させ３分間保持した後、２００℃／分の冷却速度で３０℃まで急冷し、樹脂を非晶質化させる。このようにして得られた非晶質化した樹脂をＤＳＣを用いて再び９０℃／分の昇温速度で樹脂が結晶化する１６０℃まで加熱し、２０分間保持して結晶化させる。この時１６０℃で保持開始から吸熱量を連続的に測定すると、図１に示すように一定時間経過後に吸熱ピークの最低部が出現する。本発明においては１６０℃で保持開始してから吸熱ピークの最低部が出現するまでの時間（図１におけるＴＨ）を半結晶化時間として定義する。
この半結晶化時間が短いほど樹脂の結晶性が高く、半結晶化時間が長いほど樹脂の結晶性が低いことを表す。
ポリエステル樹脂を単層で金属板に被覆する場合、半結晶化時間が５０秒未満の結晶性の高いポリエステル樹脂を用いると金属板との密着性に乏しく、薄肉化絞り加工のような厳しい加工を施すと樹脂が金属板から剥離しやすく、また樹脂層の割れやクラックも発生しやすく、好ましくない。
また本発明においては、上記のポリエステル樹脂を２層とした樹脂、すなわち上層が半結晶化時間が８０秒未満であるポリエステル樹脂、下層が半結晶化時間が５０秒以上であるポリエステル樹脂である２層のポリエステル樹脂を金属板に被覆してもよい。この２層のポリエステル樹脂を用いる場合、下層のポリエステル樹脂は金属板との密着性、特に加工時の密着性を確保するために、結晶性の低い半結晶化時間が５０秒以上であるポリエステル樹脂を用いることが好ましい。
一方、上層のポリエステル樹脂は内容物の耐透過性を向上させて耐食性を確保し、同時にフレーバー性を良好に確保するために、結晶性の高い半結晶化時間が８０秒未満であるポリエステル樹脂を用いることが好ましく、さらにこの２層のポリエステル樹脂をより効果的に用いるためには、上層の半結晶化時間が下層の半結晶化時間より短いことが好ましい。
本発明に用いる上記のポリエステル樹脂は、薄肉化絞り加工のような厳しい加工を樹脂のクラック、割れ、および剥離等を生じることなく実施可能とするため、いずれも成加工形性に優れた無配向の状態で使用する。
金属板に被覆する際の上記のポリエステル樹脂の厚さは、単層で被覆する場合は、５〜６０μｍであることが好ましく、１０〜４０μｍであることがより好ましい。厚さが５μｍ未満の場合は樹脂を金属板に被覆する作業が著しく困難となり、また薄肉化絞り加工を施した後の樹脂層に欠陥が生じやすく、耐透過性も十分ではない。一方、厚さを増加させると耐透過性は十分となるが、６０μｍ以上に厚くすることは経済的に不利となる。上下２層の樹脂を被覆する場合、上層の樹脂の厚さは２〜５７μｍ、下層の樹脂の厚さは３〜５８μｍであることが好ましい。上層の樹脂の厚さが極端に薄い場合は内容物によっては耐透過性およびフレーバー性が十分ではなくなることがあり、一方、下層の樹脂の厚さが極端に薄い場合は加工密着性が不十分となる。
上記樹脂中に、必要な特性を損なわない範囲で安定剤、酸化防止剤、シリカなどの滑剤を含有させても差し支えない。
本発明のポリエステル樹脂被覆金属板の基板となる金属板としては、通常の缶用素材として広範に使用されているぶりきや電解クロム酸処理鋼板（ティンフリースチール、以下ＴＦＳで示す）などの各種表面処理鋼板、およびアルミニウム合金板を使用することができる。表面処理鋼板としては１０〜２００ｍｇ／ｍ２の皮膜量の金属クロムからなる下層と、クロム換算で１〜３０ｍｇ／ｍ２の皮膜量のクロム水和酸化物からなる上層とからなる２層皮膜を鋼板上に形成させたティンフリースチールが好ましく、本発明のポリエステル樹脂との十分な密着性を有し、さらに耐食性も兼ね備えている。ブリキとしては、鋼板表面に錫を０．１〜１１．２ｇ／ｍ２のめっき量でめっきし、その上にクロム換算で１〜３０ｍｇ／ｍ２の皮膜量の金属クロムとクロム水和酸化物からなる２層皮膜を形成させたもの、またはクロム水和酸化物のみからなる単層皮膜を形成させたものが好ましい。いずれの場合も基板となる鋼板は缶用素材として一般的に使用されている低炭素冷延鋼板であることが好ましい。鋼板の板厚０．１〜０．３２ｍｍであることが好ましい。アルミニウム合金板に関しては、ＪＩＳの３０００系、または５０００系のものが好ましく、表面に電解クロム酸処理により、０〜２００ｍｇ／ｍ２の皮膜量の金属クロムからなる下層と、クロム換算で１〜３０ｍｇ／ｍ２の皮膜量のクロム水和酸化物からなる上層とからなる２層皮膜を形成させたものか、またはリン酸クロメート処理によりクロム換算で１〜３０ｍｇ／ｍ２のクロム成分と、リン換算で０〜３０ｍｇ／ｍ２のリン成分が付着しているものが好ましい。アルミニウム合金板の板厚は０．１５〜０．４ｍｍであることが好ましい。
本発明のポリエステル樹脂を金属板に被覆する方法としては、公知のフィルム積層法、押出積層法のいずれも適用可能である。
フィルム積層法で被覆する場合は、樹脂ペレットを樹脂の融解温度より２０〜４０℃高い温度で加熱溶融し、Ｔダイから冷却したキャストロール上にキャストし、延伸せずにコイラーに卷き取り、無配向樹脂フィルムを作製する。一方、長尺帯状の金属板をアンコイラーから解き戻しながら樹脂の融解温度より２０〜４０℃高い温度で加熱し、この加熱金属板に無配向樹脂フィルムを解き戻しながら当接し、１対のラミネートロールで挟み付けて圧着した後、結晶化を防止するため直ちに水中に急冷する。
押出積層法で被覆する場合は、樹脂ペレットを樹脂の融解温度より２０〜４０℃高い温度で加熱溶融し、アンコイラーから解き戻される長尺帯状の金属板上にＴダイから直接キャストした後、結晶化を防止するため直ちに水中に急冷する。
また、ポリエステル樹脂と金属板の間に接着剤を介在させて積層してもよい。この積層方法は、フィルム積層法において金属板のめっき層が溶解するため、金属板の温度をあまり高温とすることができないぶりきなどを使用した場合に適用される。本発明において接着剤の種類は特に規定するものではないが、エポキシ／フェノール系接着剤、エポキシ／ユリア系接着剤、ウレタン系接着剤などの接着剤が好適に使用できる。
さらに、本発明のポリエステル樹脂被覆金属板は、上記のように金属板の片面に本発明のポリエステル樹脂を被覆し、他の片面に樹脂を被覆しなくてもよいし、あるいは他の片面に本発明以外の樹脂、例えば２軸配向ポリエステル樹脂フィルム、本発明以外の無配向ポリエステル樹脂、ポリエステル以外のポリアミドやポリオレフィンなど、またはこれらの樹脂を着色した樹脂を同時に、または片面ずつ被覆してもよい。さらにまたは各種の樹脂塗料を塗装してもよい。
【実施例】
【０００５】
以下、本発明を実施例にてさらに詳細に説明する。
金属板の片面に被覆する表１に示すポリエステル樹脂、および金属板の他の片面に被覆する二酸化チタン２０重量％含有するエチレンテレフタレート８８モル％／エチレンイソフタレート１２モル％からなる共重合ポリエステル樹脂（融解温度：２２９℃）（以下、白色樹脂という）を、２軸押出機を用いてそれぞれの融解温度（Ｔｍ）より３０℃前後高い温度に加熱して溶解混合した後、ノズル幅１０００ｍｍのＴダイ（２層樹脂の場合は２層の共押出が可能なＴダイ）に送り込み、ダイノズルから押し出した後、フィルム幅：８００ｍｍにトリムし、無配向フィルムとして卷き取った。表１のＰＥＴはポリエチレンテレフタレートであり、ＰＥＴＩはエチレンテレフタレートとエチレンイソフタレート共重合ポリエステル樹脂である。また、表１中の樹脂組成の後に記載する数値はイソフタル酸のモル％を示す。試料番号８は、樹脂組成が、ＰＥＴＩ−１０モル％（６７ｗｔ％）とＰＥＴＩ−２５モル％（３３ｗｔ％）のブレンド品であることを示す。また、試料番号１７は、下層の樹脂組成が、ＰＥＴＩ−１０モル％（６７ｗｔ％）とＰＥＴＩ−２５モル％（３３ｗｔ％）のブレンド品であることを示す。
【表１】
【０００６】
金属板として下記に示す表面処理を施した長尺帯状の３種類の金属板を用意した。
１）ＴＦＳ
板厚：０．１８ｍｍ
板幅：８００ｍｍ
金属クロム量：１５０ｍｇ／ｍ２
クロム水和酸化物量：（クロムとして）１８ｍｇ／ｍ２
２）ぶりき
板厚：０．１８ｍｍ
板幅：８００ｍｍ
錫めっき量：０．２ｇ／ｍ２
クロム水和酸化物量：（クロムとして）７ｍｇ／ｍ２
３）アルミニウム合金板（ＪＩＳ ５０５２ Ｈ３９）
板厚：０．２６ｍｍ 板幅：８００ｍｍ
皮膜量：（リンとして）９ｍｇ／ｍ２
（クロムとして）８ｍｇ／ｍ２
上記のいずれかの金属板の片面に表１に示すいずれかのポリエステル樹脂の無配向フィルムを、他の片面に白色樹脂の無配向フィルムを、図２に示す装置を用いて積層した。１対のラミネートロール８と接触する直前の金属板の温度は、ＴＦＳおよびアルミニウム合金板の場合はポリエステル樹脂のＴｍより約３０℃高い温度、ぶりきの場合は２００℃とした。ぶりきに積層する場合は、事前にポリエステル樹脂および白色樹脂の無配向フィルムの片面に厚さ：１．０μｍのエポキシ／フェノール系接着剤を塗布し乾燥固化し、塗布面がぶりき面と接するようにして積層した。１５０ｍ／分の積層速度で積層した後、結晶化の進行を防止するため直ちに水中に急冷し、次いで乾燥した。
このようにして、片面にポリエステル樹脂、他の片面に白色樹脂を積層したポリエステル樹脂被覆金属板を作成した。
上記のようにして得られたポリエステル樹脂被覆金属板を、下記のように薄肉化絞り加工法を用いて有底円筒状の缶に成形加工した。
ポリエステル樹脂被覆金属板を直径：１６０ｍｍのブランクに打ち抜いた後、白色樹脂被覆面が缶の外面となるようにして、缶底径：１００ｍｍの絞り缶とした。次いで再絞り加工により、缶底径：８０ｍｍの再絞り缶とした。さらにこの再絞り缶を複合加工により、ストレッチ加工と同時にしごき加工を行い、缶底径：６５ｍｍの絞りしごき缶とした。この複合加工は、缶の上端部となる再絞り加工部としごき加工部の間隔は２０ｍｍ、再絞りダイスの肩アールは板厚の１．５倍、再絞りダイスとポンチのクリアランスは板厚の１．０倍、しごき加工部のクリアランスは元板厚の５０％となる条件で実施した。次いで公知の方法で缶上部をトリミングし、ネックイン加工、フランジ加工を施した。
次に、ポリエステル樹脂、およびポリエステル樹脂被覆金属板の評価方法を説明する。
（樹脂層の厚さ）
無配向フィルムをエポキシ系包埋樹脂に埋め込み、５μｍの厚さにスライスし、断面を顕微鏡観察して測定した。
（固有粘度（ＩＶ値））
ポリエステル樹脂をフェノール／テトラクロロエタンの１：１混合溶液に溶解させた後、３０℃の恒温浴槽中でウベローデ粘度計により比粘度を測定し、固有粘度を求めた。
（成形性）
薄肉化絞り加工法を用いて成形加工した缶を肉眼観察し、下記の基準で成形性を評価した。
◎：微小クラックやフィルム割れは認められない。
○：実用上問題とならない程度のわずかな微小クラックが認められる。
△：実用上問題となる程度のクラックおよびフィルム割れが認められる。
×：成形加工時に破胴する。
（耐食性）
薄肉化絞り加工法を用いて成形加工した缶の缶上部をトリミングし、ネックイン加工、フランジ加工を施した後、水を充填し、缶と同一のポリエステル樹脂被覆金属板から作成した蓋を卷き締めて密封し、１３０℃で３０分間加熱蒸気中で殺菌処理し、３７℃で１カ月間経時させた後開封し、缶内部の錆の発生状況を肉眼観察し、下記の基準で成形性を評価した。
◎：錆の発生は認められない。
○：実用上問題とならない程度のわずかな錆が認められる。
△：実用上問題となる程度の錆が認められる。
×：表面にかなりの錆が認められる。
（フレーバー性）
薄肉化絞り加工法を用いて成形加工した缶の缶上部をトリミングし、ネックイン加工、フランジ加工を施した後、内容物としてコーヒー飲料を充填し、缶と同一のポリエステル樹脂被覆金属板から作成した蓋を卷き締めて密封し、加熱蒸気（１３０℃）中で３０分間加熱して殺菌処理を施した。次いで、３７℃で３週間経時させた後開封し、５０人のパネラーにより内容物の経時前後のフレーバーの変化の程度を調査し、経時前後のフレーバーの差が無い、と判定したパネラーの数を基準としてフレーバー性を評価した。
◎：≧４０
○：≧３５
△：＜３５，≧３０
×：＜３０
これらの評価結果を表２に示す。
【表２】
【０００８】
表２に示すように、本発明のポリエステル樹脂被覆金属板は、いずれも成形加工性に優れ、かつ良好な耐食性およびフレーバー性を示すが、上層が高結晶性のポリエステル樹脂、下層が低結晶性のポリエステル樹脂からなる２層の樹脂で金属板を被覆することにより、さらに耐食性およびフレーバー性が優れたものになる。
【産業上の利用可能性】
【００１０】
本発明は、固有粘度が０．６〜１．４であり半結晶化時間が５０秒以上である単層のポリエステル樹脂、または上層のポリエステル樹脂の半結晶化時間が８０秒未満、下層のポリエステル樹脂の半結晶化時間が５０秒以上であり、両層の固有粘度が０．６〜１．４である２層のポリエステル樹脂を金属板の少なくとも片面に被覆したポリエステル樹脂被覆金属板であり、薄肉化絞り加工のような厳しい成形加工を施しても樹脂にクラックが生じたり割れたりすることがなく、優れた加工性および耐食性を示す。また本発明のポリエステル樹脂被覆金属板を用いた缶は、内容物のフレーバー性に優れている。
【図面の簡単な説明】
【００１１】
図１はポリエステル樹脂の半結晶化時間の一例を示す図である。
図２はポリエステル樹脂被覆金属板の製造装置の概略図である。【Technical field】
[0001]
The present invention relates to a polyester resin-coated metal plate and a can using the same. More specifically, the present invention relates to a polyester resin-coated metal plate that is excellent in moldability, corrosion resistance, and flavorability (flavor invariance) of the contents, particularly applied to beverage cans, and a can that has been deep-drawn. .
[Background]
[0002]
In recent years, a can made by using a strict molding method such as a thinning drawing process in which an oriented film obtained by stretching a polyester resin in a biaxial direction is coated on a metal plate and the drawing ratio and the reduction rate of the side wall of the can are high. , Mainly used in beverage can applications. If this biaxially oriented polyester film-coated metal plate is thinned and drawn, the resin film coated on the surface of the metal plate cannot be completely adapted to processing with a large amount of deformation, resulting in minute cracks in the film and deterioration of corrosion resistance. In some cases, the film breaks and breaks during processing, making it impossible to make cans, and it is extremely difficult to reduce the cost of cans by further increasing the drawing ratio and thickness reduction rate. When the biaxial orientation of the polyester film is reduced or non-oriented, the molding processability is improved. Corrosion resistance and flavor properties of the contents are poor when the can is filled with the contents and aged for a long time.
The present invention provides a polyester resin-coated metal plate excellent in workability and corrosion resistance without cracking or cracking even when subjected to severe forming processing such as thinning drawing processing, and contents using the same. It aims at providing the can excellent in flavor property.
DISCLOSURE OF THE INVENTION
[0003]
(1) The polyester resin-coated metal plate of the present invention is a polyester resin-coated metal plate formed by coating at least one surface of a metal plate with two layers of polyester resin having an intrinsic viscosity of 0.6 to 1.4,
The two layers of polyester resin are:
When measured using a differential scanning calorimeter (DSC),
The resin used as the upper layer has a semi-crystallization time of less than 80 seconds,
The resin used as the lower layer has a semi-crystallization time of 50 seconds or more,
And the half crystallization time of the upper layer resin is shorter than the half crystallization time of the lower layer resin ,
It is a two-layer film formed by selecting a resin satisfying the above condition and laminating it vertically .
(2) The polyester resin-coated metal plate of the present invention is characterized in that in (1), the polyester resin is non-oriented.
(3) The polyester resin-coated metal plate of the present invention is characterized in that, in the above (1) or (2), the metal plate is any one of a tin-plated steel plate, tin-free steel, and an aluminum alloy plate.
(4) The can using the polyester resin-coated metal plate of the present invention is characterized by using the polyester resin-coated metal plate of any one of (1) to (3).
[0004]
The present invention provides a single layer polyester resin having an intrinsic viscosity of 0.6 to 1.4 and a half crystallization time of 50 seconds or more, or an upper layer having a half crystallization time of less than 80 seconds and a lower layer having a half crystallization time. Is a polyester resin-coated metal plate in which two layers of polyester resin having an intrinsic viscosity of 0.6 to 1.4 are coated on at least one side of the metal plate, and the thickness is reduced by drawing. Even if severe molding processing is performed, the resin does not crack or break, and exhibits excellent workability and corrosion resistance. Moreover, the can using the polyester resin-coated metal plate of the present invention is excellent in the flavor property of the contents.
Hereinafter, the present invention will be described in detail.
First, the polyester resin applied to the present invention will be described. The polyester resin preferably has an ester unit such as ethylene terephthalate, ethylene isophthalate, butylene terephthalate, butylene isophthalate, and is a polyester mainly composed of at least one ester unit selected from these. Is preferred. At this time, each ester unit may be copolymerized, and further, a homopolymer or copolymer of two or more types of ester units may be blended and used. Other than the above, as the acid component of the ester unit, such as those using naphthalenedicarboxylic acid, adipic acid, sebacic acid, trimellitic acid, etc., and as the alcohol component of the ester unit, propylene glycol, diethylene glycol, neopentyl glycol, You may use what used cyclohexane dimethanol, pentaethysitol, etc.
In the present invention, as will be described later, it is assumed that a non-oriented polyester resin is used, and the resin is cut in the operation of coating the polyester resin on the metal plate, or the metal plate coated with the polyester resin is thinned and drawn. In order to prevent the resin from being scraped or wrinkled even when subjected to strict molding processes, and to prevent cracking, cracking, and further peeling, the inherent viscosity of the resin is increased and the resin is reinforced. There is a need. For this reason, it is preferable to make the intrinsic viscosity of said polyester resin into the range of 0.6-1.4, and it is more preferable to set it as the range of 0.8-1.2. When a polyester resin having an intrinsic viscosity of less than 0.6 is used, the strength of the resin is extremely reduced, and the polyester resin cannot be applied to a thinned drawn can that is an object of the present invention. On the other hand, when the intrinsic viscosity of the resin exceeds 1.4, the melt viscosity when the resin is heated and melted becomes extremely high, and the operation of coating the polyester resin on the metal plate becomes extremely difficult.
Moreover, when coating said polyester resin on a metal plate with a single layer, it is preferable that the half crystallization time of the polyester resin measured using the differential scanning calorimeter (DSC) is 50 seconds or more. The half crystallization time referred to in the present invention is defined as follows. That is, a certain weight of the polyester resin peeled from the polyester resin-coated metal plate is heated and melted to 290 ° C. above the melting temperature of the polyester resin at a rate of 90 ° C./min using a differential scanning calorimeter (DSC). After maintaining for 3 minutes, the resin is rapidly cooled to 30 ° C. at a cooling rate of 200 ° C./min to make the resin amorphous. The amorphous resin thus obtained is heated again to 160 ° C. at which the resin crystallizes at a rate of temperature increase of 90 ° C./min using DSC, and kept for 20 minutes for crystallization. At this time, when the endothermic amount is continuously measured at 160 ° C. from the start of holding, the end portion of the endothermic peak appears after a certain period of time as shown in FIG. In the present invention, the time from the start of holding at 160 ° C. to the appearance of the lowest endothermic peak (TH in FIG. 1) is defined as the half-crystallization time.
The shorter the half crystallization time, the higher the crystallinity of the resin, and the longer the half crystallization time, the lower the crystallinity of the resin.
When coating a metal plate with a single layer of polyester resin, if a highly crystalline polyester resin with a semi-crystallization time of less than 50 seconds is used, the adhesion to the metal plate is poor and severe processing such as thinning drawing is required. If applied, the resin is easy to peel off from the metal plate, and cracking and cracking of the resin layer are likely to occur, which is not preferable.
In the present invention, the polyester resin is a resin having two layers, that is, the upper layer is a polyester resin having a half crystallization time of less than 80 seconds, and the lower layer is a polyester resin having a half crystallization time of 50 seconds or more. A layer of polyester resin may be coated on the metal plate. When this two-layer polyester resin is used, the lower layer polyester resin has a low crystallinity and a semi-crystallization time of 50 seconds or more in order to ensure adhesion to the metal plate, particularly adhesion during processing. Is preferably used.
On the other hand, the upper layer polyester resin improves the permeation resistance of the contents to ensure corrosion resistance, and at the same time, in order to ensure good flavor properties, a polyester resin having a high crystallinity and a semi-crystallization time of less than 80 seconds is used. In order to use the two-layer polyester resin more effectively, it is preferable that the upper half-crystallization time is shorter than the lower half-crystallization time.
The above-mentioned polyester resin used in the present invention can be subjected to severe processing such as thinning drawing processing without causing cracking, cracking, peeling, etc. of the resin. Use in the state.
The thickness of the above-mentioned polyester resin when coated on a metal plate is preferably 5 to 60 μm, more preferably 10 to 40 μm when coated with a single layer. When the thickness is less than 5 μm, it becomes extremely difficult to coat the resin on the metal plate, and the resin layer after the thinning drawing process is likely to be defective, and the permeation resistance is not sufficient. On the other hand, when the thickness is increased, the permeation resistance is sufficient, but it is economically disadvantageous to increase the thickness to 60 μm or more. When coating the upper and lower two layers of resin, the thickness of the upper layer resin is preferably 2 to 57 μm, and the thickness of the lower layer resin is preferably 3 to 58 μm. When the upper layer resin is extremely thin, the permeation resistance and flavor may not be sufficient depending on the contents. On the other hand, when the lower layer resin is extremely thin, the work adhesion is insufficient. It becomes.
The resin may contain a lubricant such as a stabilizer, an antioxidant and silica as long as necessary properties are not impaired.
The metal plate used as the substrate of the polyester resin-coated metal plate of the present invention includes various types such as tinplate and electrolytic chromic acid-treated steel plates (tin free steel, hereinafter referred to as TFS) widely used as ordinary can materials. Surface-treated steel plates and aluminum alloy plates can be used. As a surface-treated steel sheet, a two- layer coating composed of a lower layer made of chromium metal with a coating amount of 10 to 200 mg / m 2 and an upper layer made of chromium hydrated oxide with a coating amount of 1 to 30 mg / m 2 in terms of chromium. Tin-free steel formed on a steel plate is preferable, has sufficient adhesion with the polyester resin of the present invention, and also has corrosion resistance. The tin and tin on the surface of the steel sheet plated with a plating amount of 0.1~11.2g / m 2, coating weight of metallic chromium and hydrated chromium oxide of 1 to 30 mg / m 2 in terms of chromium thereon A film formed with a two-layer film made of or a film formed with a single-layer film made only of chromium hydrated oxide is preferable. In any case, the steel plate used as the substrate is preferably a low carbon cold-rolled steel plate generally used as a can material. It is preferable that the thickness of the steel sheet is 0.1 to 0.32 mm. The aluminum alloy plate is preferably JIS 3000 or 5000, and the surface is formed by electrochromic acid treatment with a lower layer of metal chromium having a coating amount of 0 to 200 mg / m 2 and 1 to 30 mg in terms of chromium. Either a two-layer coating consisting of an upper layer made of chromium hydrated oxide with a coating amount of / m 2 or a chromium component of 1 to 30 mg / m 2 in terms of chromium and phosphorous conversion by phosphoric acid chromate treatment It is preferable that 0 to 30 mg / m 2 of phosphorus component is attached. The thickness of the aluminum alloy plate is preferably 0.15 to 0.4 mm.
As a method for coating the metal plate with the polyester resin of the present invention, any of a known film laminating method and extrusion laminating method can be applied.
When coating by the film lamination method, the resin pellets are heated and melted at a temperature 20 to 40 ° C. higher than the melting temperature of the resin, cast on a cast roll cooled from a T-die, and wound on a coiler without stretching. A non-oriented resin film is produced. On the other hand, a long strip-shaped metal plate is heated at a temperature 20 to 40 ° C. higher than the melting temperature of the resin while being unwound from the uncoiler, and is brought into contact with the heated metal plate while unwinding the non-oriented resin film. After being sandwiched with and crimped, immediately cooled in water to prevent crystallization.
When coating by extrusion laminating method, the resin pellets are heated and melted at a temperature 20 to 40 ° C. higher than the melting temperature of the resin, cast directly from a T-die on a long strip-shaped metal plate unwound from the uncoiler, and then crystallized. Immediately cool in water to prevent oxidization.
Moreover, you may laminate | stack by interposing an adhesive agent between a polyester resin and a metal plate. This laminating method is applied in the case of using tinplate that cannot make the temperature of the metal plate so high because the plating layer of the metal plate dissolves in the film laminating method. In the present invention, the type of the adhesive is not particularly defined, but an adhesive such as an epoxy / phenol adhesive, an epoxy / urea adhesive, and a urethane adhesive can be preferably used.
Furthermore, as described above, the polyester resin-coated metal plate of the present invention may be coated with the polyester resin of the present invention on one side of the metal plate and may not be coated with the resin on the other side, or may be coated on the other side. A resin other than the invention, for example, a biaxially oriented polyester resin film, a non-oriented polyester resin other than the present invention, a polyamide or polyolefin other than polyester, or a resin colored with these resins may be coated simultaneously or one side at a time. Further or various resin paints may be applied.
【Example】
[0005]
Hereinafter, the present invention will be described in more detail with reference to examples.
A polyester resin shown in Table 1 coated on one side of a metal plate, and a copolymerized polyester resin comprising 88% by mole of ethylene terephthalate / 12% by mole of ethylene isophthalate containing 20% by weight of titanium dioxide coated on the other side of the metal plate ( (Melting temperature: 229 ° C.) (hereinafter referred to as white resin) was heated and mixed at a temperature about 30 ° C. higher than the respective melting temperature (Tm) using a twin screw extruder, and then a T die having a nozzle width of 1000 mm (In the case of a two-layer resin, it was fed into a T-die capable of co-extrusion of two layers), extruded from a die nozzle, trimmed to a film width: 800 mm, and scraped off as a non-oriented film. The PET in Table 1 is polyethylene terephthalate, and PETI is an ethylene terephthalate and ethylene isophthalate copolymer polyester resin. Moreover, the numerical value described after the resin composition in Table 1 shows mol% of isophthalic acid. Sample number 8 indicates that the resin composition is a blended product of PETI-10 mol% (67 wt%) and PETI-25 mol% (33 wt%). Sample number 17 indicates that the resin composition of the lower layer is a blended product of PETI-10 mol% (67 wt%) and PETI-25 mol% (33 wt%).
[Table 1]
[0006]
As the metal plate, three types of long-band metal plates subjected to the following surface treatment were prepared.
1) TFS
Plate thickness: 0.18mm
Board width: 800mm
Metal chromium content: 150 mg / m 2
Chromium hydrated oxide content: 18 mg / m 2 (as chromium)
2) Tin plate thickness: 0.18mm
Board width: 800mm
Tin plating amount: 0.2 g / m 2
Chromium hydrated oxide content: 7 mg / m 2 (as chromium)
3) Aluminum alloy plate (JIS 5052 H39)
Plate thickness: 0.26mm Plate width: 800mm
Amount of coating: 9 mg / m 2 (as phosphorus)
8 mg / m 2 (as chromium)
The non-oriented film of any polyester resin shown in Table 1 on one side of any of the above metal plates and the non-oriented film of white resin on the other side were laminated using the apparatus shown in FIG. The temperature of the metal plate immediately before contacting with the pair of laminate rolls 8 was about 30 ° C. higher than Tm of the polyester resin in the case of TFS and aluminum alloy plate, and 200 ° C. in the case of tinting. In the case of laminating with a tinplate, an epoxy / phenolic adhesive with a thickness of 1.0 μm is applied in advance to one side of a non-oriented film of a polyester resin and a white resin and dried and solidified. In this way, lamination was performed. After laminating at a laminating speed of 150 m / min, it was immediately quenched into water to prevent the progress of crystallization and then dried.
In this way, a polyester resin-coated metal plate was prepared by laminating a polyester resin on one side and a white resin on the other side.
The polyester resin-coated metal plate obtained as described above was molded into a bottomed cylindrical can using the thinning drawing method as described below.
After punching the polyester resin-coated metal plate into a blank having a diameter of 160 mm, the white resin-coated surface was the outer surface of the can to obtain a drawn can having a can bottom diameter of 100 mm. Next, a redraw can with a can bottom diameter of 80 mm was made by redraw processing. Further, this redrawn can was subjected to ironing at the same time as stretch processing by composite processing to obtain a can bottom ironing can with a diameter of 65 mm. In this combined processing, the distance between the redrawing portion and the ironing portion that becomes the upper end of the can is 20 mm, the shoulder radius of the redrawing die is 1.5 times the plate thickness, and the clearance between the redrawing die and the punch is the plate thickness. The clearance of the ironing portion was 1.0 times, and the condition was 50% of the original plate thickness. Next, the upper part of the can was trimmed by a known method, and neck-in processing and flange processing were performed.
Next, a method for evaluating a polyester resin and a polyester resin-coated metal plate will be described.
(Resin layer thickness)
The non-oriented film was embedded in an epoxy embedding resin, sliced to a thickness of 5 μm, and the cross section was observed with a microscope and measured.
(Intrinsic viscosity (IV value))
After the polyester resin was dissolved in a 1: 1 mixed solution of phenol / tetrachloroethane, the specific viscosity was measured with an Ubbelohde viscometer in a constant temperature bath at 30 ° C. to determine the intrinsic viscosity.
(Formability)
The cans molded using the thinning drawing method were observed with the naked eye, and the moldability was evaluated according to the following criteria.
(Double-circle): A micro crack and a film crack are not recognized.
○: Slight micro cracks that do not cause a problem in practical use are recognized.
(Triangle | delta): The crack and film crack of a grade which are a problem in practical use are recognized.
×: Destructed during molding.
(Corrosion resistance)
After trimming the top of the can molded using the thinning drawing method, necking in and flange processing, filling with water, and covering the lid made from the same polyester resin coated metal plate as the can Tightened and sealed, sterilized in heated steam at 130 ° C for 30 minutes, aged for 1 month at 37 ° C, opened, and visually observed the occurrence of rust inside the can. Evaluated.
A: Generation of rust is not recognized.
○: A slight amount of rust that is not a problem in practical use is recognized.
(Triangle | delta): Rust of the grade which is a problem practically is recognized.
X: Considerable rust is observed on the surface.
(Flavoring)
Trimming the top of the can that has been molded using the thinning drawing method, necking in and flange processing, filling with coffee beverage as the contents, and making from the same polyester resin coated metal plate as the can The lid was tightened and sealed, and sterilized by heating in heated steam (130 ° C.) for 30 minutes. Next, after opening for 3 weeks at 37 ° C., the package was opened, and the panel was examined by 50 panelists to examine the degree of flavor change before and after the aging. The number of panelists judged to have no difference in flavor before and after aging. The flavor property was evaluated as a standard.
◎: ≧ 40
○: ≧ 35
Δ: <35, ≧ 30
×: <30
These evaluation results are shown in Table 2.
[Table 2]
[0008]
As shown in Table 2, the polyester resin-coated metal sheet of the present invention is excellent in molding processability and exhibits good corrosion resistance and flavor, but the upper layer is a highly crystalline polyester resin and the lower layer is low crystalline. By coating the metal plate with a two-layered resin made of polyester resin, the corrosion resistance and flavor properties are further improved.
[Industrial applicability]
[0010]
The present invention relates to a single layer polyester resin having an intrinsic viscosity of 0.6 to 1.4 and a half crystallization time of 50 seconds or more, or a half layer crystallization time of an upper layer polyester resin of less than 80 seconds, and a lower layer polyester. A polyester resin-coated metal plate in which a resin half-crystallization time is 50 seconds or more and two layers of polyester resin having an intrinsic viscosity of both layers of 0.6 to 1.4 are coated on at least one side of the metal plate, Even if severe molding processing such as thinning drawing is performed, the resin does not crack or break, and exhibits excellent workability and corrosion resistance. Moreover, the can using the polyester resin-coated metal plate of the present invention is excellent in the flavor property of the contents.
[Brief description of the drawings]
[0011]
FIG. 1 is a diagram showing an example of a half crystallization time of a polyester resin.
FIG. 2 is a schematic view of an apparatus for producing a polyester resin-coated metal plate.
Claims (4)
前記２層のポリエステル樹脂は、
示差走査熱分析装置（ＤＳＣ）を用いて測定した場合に、
上層とする樹脂はその半結晶化時間が８０秒未満、
下層とする樹脂はその半結晶化時間が５０秒以上、
かつ、上層の樹脂の半結晶化時間が下層の樹脂の半結晶化時間より短い、
という条件を満たす樹脂を選択して上下に積層してなる２層フィルムである
ことを特徴とするポリエステル樹脂被覆金属板。A polyester resin-coated metal plate obtained by coating two layers of polyester resin having an intrinsic viscosity of 0.6 to 1.4 on at least one surface of a metal plate,
The two layers of polyester resin are:
When measured using a differential scanning calorimeter (DSC),
The resin used as the upper layer has a semi-crystallization time of less than 80 seconds,
The resin used as the lower layer has a semi-crystallization time of 50 seconds or more,
And the half crystallization time of the upper layer resin is shorter than the half crystallization time of the lower layer resin ,
A polyester resin-coated metal plate, which is a two-layer film obtained by selecting a resin satisfying the following condition and laminating it vertically .
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8156299 | 1999-03-25 | ||
| PCT/JP2000/001631 WO2000058087A1 (en) | 1999-03-25 | 2000-03-17 | Metal plate coated with polyester resin, and can using the same |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JP4319358B2 true JP4319358B2 (en) | 2009-08-26 |
Family
ID=13749743
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2000607819A Expired - Lifetime JP4319358B2 (en) | 1999-03-25 | 2000-03-17 | Polyester resin-coated metal plate and can using the same |
Country Status (3)
| Country | Link |
|---|---|
| JP (1) | JP4319358B2 (en) |
| AU (1) | AU3193400A (en) |
| WO (1) | WO2000058087A1 (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4775532B2 (en) * | 2001-08-23 | 2011-09-21 | 東洋製罐株式会社 | Resin coated seamless can |
| JP2005161621A (en) * | 2003-12-01 | 2005-06-23 | Jfe Steel Kk | Laminated metal sheet for can lid excellent in appearance after retorting |
| EP1688188B1 (en) * | 2005-02-02 | 2012-04-11 | Toyo Kohan Co., Ltd. | Metal plate coated with polyester resin, and can using the same |
| EP1688187A1 (en) * | 2005-02-02 | 2006-08-09 | Toyo Kohan Co., Ltd. | Metal plate coated with polyester resin, and can using the same |
| JP5609012B2 (en) | 2009-05-28 | 2014-10-22 | 東洋製罐株式会社 | Steel drawn iron can and method for producing the same |
| JP5609036B2 (en) | 2009-07-22 | 2014-10-22 | 東洋製罐株式会社 | Aluminum drawn iron can and method for producing the same |
| JP6583880B2 (en) | 2015-06-16 | 2019-10-02 | 東洋鋼鈑株式会社 | Polyester resin-coated metal plate and container using the same |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH1160755A (en) * | 1997-08-12 | 1999-03-05 | Mitsubishi Kagaku Polyester Film Kk | Polyester film for coating metal can |
| JPH11209483A (en) * | 1998-01-23 | 1999-08-03 | Teijin Ltd | White polyester film for forming metal sheet laninate |
-
2000
- 2000-03-17 JP JP2000607819A patent/JP4319358B2/en not_active Expired - Lifetime
- 2000-03-17 AU AU31934/00A patent/AU3193400A/en not_active Abandoned
- 2000-03-17 WO PCT/JP2000/001631 patent/WO2000058087A1/en active Application Filing
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| AU3193400A (en) | 2000-10-16 |
| WO2000058087A1 (en) | 2000-10-05 |
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