JP4680528B2 - Ethylene resin foam sheet for thermoforming, molded article, and method for producing ethylene resin foam sheet for thermoforming - Google Patents
Ethylene resin foam sheet for thermoforming, molded article, and method for producing ethylene resin foam sheet for thermoforming Download PDFInfo
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- JP4680528B2 JP4680528B2 JP2004111624A JP2004111624A JP4680528B2 JP 4680528 B2 JP4680528 B2 JP 4680528B2 JP 2004111624 A JP2004111624 A JP 2004111624A JP 2004111624 A JP2004111624 A JP 2004111624A JP 4680528 B2 JP4680528 B2 JP 4680528B2
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- 229920005989 resin Polymers 0.000 title claims description 241
- 239000011347 resin Substances 0.000 title claims description 241
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 title claims description 218
- 239000005977 Ethylene Substances 0.000 title claims description 218
- 239000006260 foam Substances 0.000 title claims description 149
- 238000003856 thermoforming Methods 0.000 title claims description 136
- 238000004519 manufacturing process Methods 0.000 title claims description 35
- 229920001903 high density polyethylene Polymers 0.000 claims description 42
- 239000004700 high-density polyethylene Substances 0.000 claims description 42
- 239000004088 foaming agent Substances 0.000 claims description 34
- 238000005187 foaming Methods 0.000 claims description 24
- 229920005992 thermoplastic resin Polymers 0.000 claims description 16
- 239000000203 mixture Substances 0.000 claims description 6
- 238000004898 kneading Methods 0.000 claims description 2
- 210000004027 cell Anatomy 0.000 description 69
- 238000000034 method Methods 0.000 description 27
- 238000002844 melting Methods 0.000 description 20
- 230000008018 melting Effects 0.000 description 20
- 238000001125 extrusion Methods 0.000 description 18
- 239000000155 melt Substances 0.000 description 17
- 238000000465 moulding Methods 0.000 description 13
- KRKNYBCHXYNGOX-UHFFFAOYSA-N citric acid Chemical compound OC(=O)CC(O)(C(O)=O)CC(O)=O KRKNYBCHXYNGOX-UHFFFAOYSA-N 0.000 description 12
- 238000012360 testing method Methods 0.000 description 11
- 230000003746 surface roughness Effects 0.000 description 10
- UIIMBOGNXHQVGW-UHFFFAOYSA-M Sodium bicarbonate Chemical compound [Na+].OC([O-])=O UIIMBOGNXHQVGW-UHFFFAOYSA-M 0.000 description 8
- 239000000178 monomer Substances 0.000 description 7
- 239000002667 nucleating agent Substances 0.000 description 6
- 229920000098 polyolefin Polymers 0.000 description 6
- 238000004804 winding Methods 0.000 description 6
- 230000007423 decrease Effects 0.000 description 5
- 238000005259 measurement Methods 0.000 description 5
- 239000008188 pellet Substances 0.000 description 5
- VXNZUUAINFGPBY-UHFFFAOYSA-N 1-Butene Chemical compound CCC=C VXNZUUAINFGPBY-UHFFFAOYSA-N 0.000 description 4
- LIKMAJRDDDTEIG-UHFFFAOYSA-N 1-hexene Chemical compound CCCCC=C LIKMAJRDDDTEIG-UHFFFAOYSA-N 0.000 description 4
- KWKAKUADMBZCLK-UHFFFAOYSA-N 1-octene Chemical compound CCCCCCC=C KWKAKUADMBZCLK-UHFFFAOYSA-N 0.000 description 4
- WSSSPWUEQFSQQG-UHFFFAOYSA-N 4-methyl-1-pentene Chemical compound CC(C)CC=C WSSSPWUEQFSQQG-UHFFFAOYSA-N 0.000 description 4
- 150000001336 alkenes Chemical class 0.000 description 4
- 238000001816 cooling Methods 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- OFBQJSOFQDEBGM-UHFFFAOYSA-N n-pentane Natural products CCCCC OFBQJSOFQDEBGM-UHFFFAOYSA-N 0.000 description 4
- 229910000030 sodium bicarbonate Inorganic materials 0.000 description 4
- 235000017557 sodium bicarbonate Nutrition 0.000 description 4
- 239000004604 Blowing Agent Substances 0.000 description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 3
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 3
- 229910052799 carbon Inorganic materials 0.000 description 3
- 229920001577 copolymer Polymers 0.000 description 3
- 125000000524 functional group Chemical group 0.000 description 3
- 230000005484 gravity Effects 0.000 description 3
- 125000004435 hydrogen atom Chemical group [H]* 0.000 description 3
- JRZJOMJEPLMPRA-UHFFFAOYSA-N olefin Natural products CCCCCCCC=C JRZJOMJEPLMPRA-UHFFFAOYSA-N 0.000 description 3
- 239000001301 oxygen Substances 0.000 description 3
- 229910052760 oxygen Inorganic materials 0.000 description 3
- 230000002093 peripheral effect Effects 0.000 description 3
- 238000010998 test method Methods 0.000 description 3
- 239000004156 Azodicarbonamide Substances 0.000 description 2
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- LCGLNKUTAGEVQW-UHFFFAOYSA-N Dimethyl ether Chemical compound COC LCGLNKUTAGEVQW-UHFFFAOYSA-N 0.000 description 2
- BAPJBEWLBFYGME-UHFFFAOYSA-N Methyl acrylate Chemical compound COC(=O)C=C BAPJBEWLBFYGME-UHFFFAOYSA-N 0.000 description 2
- XOZUGNYVDXMRKW-AATRIKPKSA-N azodicarbonamide Chemical compound NC(=O)\N=N\C(N)=O XOZUGNYVDXMRKW-AATRIKPKSA-N 0.000 description 2
- 235000019399 azodicarbonamide Nutrition 0.000 description 2
- 239000001273 butane Substances 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000009413 insulation Methods 0.000 description 2
- 238000010030 laminating Methods 0.000 description 2
- TVMXDCGIABBOFY-UHFFFAOYSA-N n-Octanol Natural products CCCCCCCC TVMXDCGIABBOFY-UHFFFAOYSA-N 0.000 description 2
- IJDNQMDRQITEOD-UHFFFAOYSA-N n-butane Chemical compound CCCC IJDNQMDRQITEOD-UHFFFAOYSA-N 0.000 description 2
- 229920003023 plastic Polymers 0.000 description 2
- 239000004033 plastic Substances 0.000 description 2
- QQONPFPTGQHPMA-UHFFFAOYSA-N propylene Natural products CC=C QQONPFPTGQHPMA-UHFFFAOYSA-N 0.000 description 2
- 125000004805 propylene group Chemical group [H]C([H])([H])C([H])([*:1])C([H])([H])[*:2] 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- 238000000638 solvent extraction Methods 0.000 description 2
- 238000007666 vacuum forming Methods 0.000 description 2
- 230000000007 visual effect Effects 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- SMZOUWXMTYCWNB-UHFFFAOYSA-N 2-(2-methoxy-5-methylphenyl)ethanamine Chemical compound COC1=CC=C(C)C=C1CCN SMZOUWXMTYCWNB-UHFFFAOYSA-N 0.000 description 1
- NIXOWILDQLNWCW-UHFFFAOYSA-N 2-Propenoic acid Natural products OC(=O)C=C NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 description 1
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 1
- 238000012935 Averaging Methods 0.000 description 1
- MWRWFPQBGSZWNV-UHFFFAOYSA-N Dinitrosopentamethylenetetramine Chemical compound C1N2CN(N=O)CN1CN(N=O)C2 MWRWFPQBGSZWNV-UHFFFAOYSA-N 0.000 description 1
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 1
- IMROMDMJAWUWLK-UHFFFAOYSA-N Ethenol Chemical compound OC=C IMROMDMJAWUWLK-UHFFFAOYSA-N 0.000 description 1
- 239000004594 Masterbatch (MB) Substances 0.000 description 1
- CERQOIWHTDAKMF-UHFFFAOYSA-N Methacrylic acid Chemical compound CC(=C)C(O)=O CERQOIWHTDAKMF-UHFFFAOYSA-N 0.000 description 1
- VVQNEPGJFQJSBK-UHFFFAOYSA-N Methyl methacrylate Chemical compound COC(=O)C(C)=C VVQNEPGJFQJSBK-UHFFFAOYSA-N 0.000 description 1
- XTXRWKRVRITETP-UHFFFAOYSA-N Vinyl acetate Chemical compound CC(=O)OC=C XTXRWKRVRITETP-UHFFFAOYSA-N 0.000 description 1
- 230000001133 acceleration Effects 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- VJRITMATACIYAF-UHFFFAOYSA-N benzenesulfonohydrazide Chemical compound NNS(=O)(=O)C1=CC=CC=C1 VJRITMATACIYAF-UHFFFAOYSA-N 0.000 description 1
- 230000003139 buffering effect Effects 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 210000000170 cell membrane Anatomy 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000002425 crystallisation Methods 0.000 description 1
- 230000008025 crystallization Effects 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- -1 dimethyl ether Chemical class 0.000 description 1
- 238000000635 electron micrograph Methods 0.000 description 1
- 150000002170 ethers Chemical class 0.000 description 1
- 238000011049 filling Methods 0.000 description 1
- 238000010097 foam moulding Methods 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 150000004820 halides Chemical class 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 229920001519 homopolymer Polymers 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 150000002430 hydrocarbons Chemical class 0.000 description 1
- 229910001872 inorganic gas Inorganic materials 0.000 description 1
- 238000005304 joining Methods 0.000 description 1
- 150000002576 ketones Chemical class 0.000 description 1
- 229920001684 low density polyethylene Polymers 0.000 description 1
- 239000004702 low-density polyethylene Substances 0.000 description 1
- 238000000691 measurement method Methods 0.000 description 1
- 239000010445 mica Substances 0.000 description 1
- 229910052618 mica group Inorganic materials 0.000 description 1
- JCXJVPUVTGWSNB-UHFFFAOYSA-N nitrogen dioxide Inorganic materials O=[N]=O JCXJVPUVTGWSNB-UHFFFAOYSA-N 0.000 description 1
- 239000000088 plastic resin Substances 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 229920005606 polypropylene copolymer Polymers 0.000 description 1
- 229920001384 propylene homopolymer Polymers 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 238000007493 shaping process Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 239000000454 talc Substances 0.000 description 1
- 229910052623 talc Inorganic materials 0.000 description 1
- 238000005979 thermal decomposition reaction Methods 0.000 description 1
- 229920001169 thermoplastic Polymers 0.000 description 1
- 239000004416 thermosoftening plastic Substances 0.000 description 1
- 238000009834 vaporization Methods 0.000 description 1
- 230000008016 vaporization Effects 0.000 description 1
Landscapes
- Extrusion Moulding Of Plastics Or The Like (AREA)
- Blow-Moulding Or Thermoforming Of Plastics Or The Like (AREA)
- Molding Of Porous Articles (AREA)
- Compositions Of Macromolecular Compounds (AREA)
- Manufacture Of Porous Articles, And Recovery And Treatment Of Waste Products (AREA)
- Laminated Bodies (AREA)
Description
本発明は、熱成形用エチレン系樹脂発泡シート、成形品及び熱成形用エチレン系樹脂発泡シートの製造方法に関する。 The present invention relates to a thermoforming ethylene resin foam sheet, a molded article, and a method for producing a thermoforming ethylene resin foam sheet.
高密度ポリエチレンは、耐熱性、耐寒性、機械的強度及び耐薬品性に優れていることから、種々の用途に用いられており、断熱性、柔軟性及び緩衝性を付与するために発泡させたものが一部実用化されている。 High density polyethylene is excellent in heat resistance, cold resistance, mechanical strength and chemical resistance, so it is used in various applications and foamed to give heat insulation, flexibility and buffering properties. Some have been put into practical use.
ここで、エチレン系樹脂は結晶性高分子であることから、その物理的特性は融点を境に顕著に変化する。具体的には、エチレン系樹脂を融点未満の温度から加熱していくと、エチレン系樹脂は、融点よりも高い温度で急激に溶融粘度が低下し、発泡に要する溶融粘度が得られにくい反面、エチレン系樹脂を融点を超えた温度から冷却していくと、融点未満の温度で急激に結晶化を生じて流動しなくなることから、エチレン系樹脂を発泡に適した溶融粘度とするためには、エチレン系樹脂の融点付近の狭い温度領域にてエチレン系樹脂の温度を調整しなければならない。 Here, since the ethylene-based resin is a crystalline polymer, its physical characteristics change significantly with the melting point as a boundary. Specifically, when the ethylene resin is heated from a temperature lower than the melting point, the ethylene resin suddenly decreases in melt viscosity at a temperature higher than the melting point, but it is difficult to obtain the melt viscosity required for foaming, When the ethylene resin is cooled from a temperature exceeding the melting point, it suddenly crystallizes at a temperature below the melting point and does not flow, so in order to make the ethylene resin a melt viscosity suitable for foaming, The temperature of the ethylene resin must be adjusted in a narrow temperature range near the melting point of the ethylene resin.
このような特性を有するエチレン系樹脂のうち、低密度ポリエチレンは、その分子鎖に適度な長さの長鎖分岐を有していることから、分子鎖同士の絡み合いによって溶融時の溶融粘度が比較的高いと共に、融点付近における結晶性の変化についても他のエチレン系樹脂に比して緩やかであり、上述のように融点付近での狭い温度領域の調整が必要ではあるが、他のエチレン系樹脂に比して比較的容易に発泡させることができる。 Among ethylene-based resins having such characteristics, low-density polyethylene has long chain branching of an appropriate length in its molecular chain, so the melt viscosity at the time of melting is compared by the entanglement of molecular chains. The change in crystallinity near the melting point is moderate compared to other ethylene resins, and adjustment of a narrow temperature region near the melting point is necessary as described above. It is possible to foam relatively easily as compared with the above.
これに対して、高密度ポリエチレンは、その分子鎖に分岐が少ないために溶融時における溶融粘度が非常に低い上に、結晶性が高く、結晶化する速度も速いために、発泡に適した溶融粘度とするためには、更に狭い温度領域の調整が必要となり、よって、高密度ポリエチレンを発泡化させて独立気泡率の高い発泡体を製造することは非常に困難なものであった。 On the other hand, high-density polyethylene has a very low melt viscosity at the time of melting because there are few branches in the molecular chain, and also has a high crystallinity and a high crystallization speed. In order to obtain a viscosity, it is necessary to adjust a narrower temperature range. Therefore, it has been very difficult to produce a foam having a high closed cell ratio by foaming high-density polyethylene.
又、高密度ポリエチレンの溶融粘度を向上させるために、高密度ポリエチレンの分子量を大きくすることが考えられるものの、高密度ポリエチレンの分子量を大きくすると、押出機のモータに大きな負担をかけることとなり、押出ができなくなったり或いは押出機内の樹脂温度を大幅に上昇させなければならないといった問題点があった。 Although it is conceivable to increase the molecular weight of the high-density polyethylene in order to improve the melt viscosity of the high-density polyethylene, increasing the molecular weight of the high-density polyethylene places a heavy burden on the motor of the extruder. There is a problem that it becomes impossible to perform the process or the temperature of the resin in the extruder has to be significantly increased.
そして、特許文献１には、見掛け比重が０．０１２〜０．１０と高発泡倍率である高密度ポリエチレン発泡体が提案されている。しかしながら、このような高発泡倍率の高密度ポリエチレン発泡体は、その製造に際して多量の発泡剤を使用していることから、発泡時に発泡剤の蒸発潜熱による溶融樹脂の冷却効果を利用することができ、見掛け比重が０．１０を超えた高密度ポリエチレン発泡体よりも製造が容易であるが、高発泡倍率の高密度ポリエチレン発泡体は機械的強度に劣り熱成形ができないといった問題点があった。 Patent Document 1 proposes a high-density polyethylene foam having an apparent specific gravity of 0.012 to 0.10 and a high expansion ratio. However, since such a high-density polyethylene foam having a high expansion ratio uses a large amount of foaming agent in the production thereof, the cooling effect of the molten resin due to the latent heat of vaporization of the foaming agent can be utilized during foaming. The high density polyethylene foam having an apparent specific gravity exceeding 0.10 is easier to produce, but the high density polyethylene foam having a high expansion ratio is inferior in mechanical strength and cannot be thermoformed.
本発明者は、上述のように、所定の見掛け密度を有するエチレン系樹脂発泡シートの製造が難しい状況下において、エチレン系樹脂の溶融樹脂特性として、メルトマスフローレート、溶融張力及び破断伸びを、又、エチレン系樹脂の結晶特性として樹脂密度を指標として研究を進めた。 As described above, the present inventor, in the situation where it is difficult to produce an ethylene-based resin foam sheet having a predetermined apparent density, the melt resin characteristics of the ethylene-based resin include the melt mass flow rate, the melt tension, and the elongation at break. As a crystal characteristic of ethylene-based resin, research was conducted using resin density as an index.
しかしながら、上記エチレン系樹脂の指標は、エチレン系樹脂の発泡性や発泡シートの成形性との関係が低く、上記指標を調整しても良好な発泡シートを安定的に得ることができず、得られた発泡シートは、表面平滑性や熱成形性に劣るものであった。 However, the index of the ethylene-based resin has a low relationship with the foamability of the ethylene-based resin and the moldability of the foamed sheet, and even if the index is adjusted, a good foamed sheet cannot be stably obtained. The obtained foamed sheet was inferior in surface smoothness and thermoformability.
そこで、本発明者らは、溶融樹脂特性のうち溶融弾性特性に主眼をおき、この溶融弾性特性の指標の一つであるダイスェルに着目して鋭意研究した結果、このダイスェルを特定値以上とすることによって、得られるエチレン系樹脂発泡シートが、均一で微細な独立気泡を有し且つ外観性及び熱成形性に優れたものとなることを見出したものである。 Therefore, the present inventors focused on the melt elastic property among the molten resin properties, and as a result of diligent research focusing on the die shell which is one of the indices of the melt elastic property, the die shell is set to a specific value or more. Thus, it has been found that the obtained ethylene-based resin foam sheet has uniform and fine closed cells and is excellent in appearance and thermoformability.
本発明は、均一で微細な独立気泡を有し且つ外観性及び熱成形性に優れた熱成形用エチレン系樹脂発泡シート及びその製造方法を提供する。 The present invention provides an ethylene-based resin foam sheet for thermoforming that has uniform and fine closed cells and is excellent in appearance and thermoformability, and a method for producing the same.
本発明の熱成形用エチレン系樹脂発泡シートは、密度が０．９４５〜０．９７０ｇ／ｃｍ 3 の高密度ポリエチレンを７０〜８５重量％含有し且つ１９０℃におけるダイスェルが１．５５〜１．９０であるエチレン系樹脂からなると共に、見掛け密度が０．１１〜０．８０ｇ／ｃｍ3 、厚みが０．５〜５．０ｍｍ、連続気泡率が５０％以下であることを特徴とする。 Heat molding the ethylene-based resin foam sheet of the present invention, Daisueru in density containing high-density polyethylene 0.945~0.970g / cm 3 70 ~ 85 wt% and 190 ° C. is from 1.55 to 1.90 And an apparent density of 0.11 to 0.80 g / cm 3 , a thickness of 0.5 to 5.0 mm, and an open cell ratio of 50% or less.
本発明の熱成形用エチレン系樹脂発泡シートを構成するエチレン系樹脂は、密度が０．９４５〜０．９７０ｇ／ｃｍ 3 の高密度ポリエチレンを７０〜８５重量％含有し且つ１９０℃におけるダイスェルが１．５５〜１．９０であるエチレン系樹脂からなる。 The ethylene resin constituting the ethylene-based resin foam sheet for thermoforming of the present invention contains 70 to 85 % by weight of high-density polyethylene having a density of 0.945 to 0.970 g / cm 3 and has a die shell of 1 at 190 ° C. It is made of an ethylene-based resin that is 55 to 1.90.
本発明においてエチレン系樹脂とは、エチレンの単独重合体、エチレンと１−オレフィン単量体との共重合体、及び、エチレンと官能基に炭素、酸素及び水素原子だけをもつ非オレフィン単量体との共重合体をいい、単独で用いられても二種以上が併用されてもよい。 In the present invention, the ethylene-based resin is an ethylene homopolymer, a copolymer of ethylene and a 1-olefin monomer, and a non-olefin monomer having only ethylene, carbon, oxygen and hydrogen atoms in the functional group. And may be used alone or in combination of two or more.
ここで、１−オレフィンとしては、例えば、プロピレン、１−ブテン、１−ヘキセン、１−オクテン、４−メチル−１−ペンテンなどが挙げられ、官能基に炭素、酸素及び水素原子だけをもつ非オレフィン単量体としては、例えば、酢酸ビニル、ビニルアルコール、アクリル酸、メタクリル酸、メチルアクリレート、メチルメタクリレートなどが挙げられる。なお、エチレンと１−オレフィン単量体との共重合体、及び、エチレンと官能基に炭素、酸素及び水素原子だけをもつ非オレフィン単量体との共重合体において、エチレン含有量は７０モル％以上が好ましく、８０〜９７モル％がより好ましい。 Here, examples of the 1-olefin include propylene, 1-butene, 1-hexene, 1-octene, 4-methyl-1-pentene, and the like, and the functional group has only carbon, oxygen, and hydrogen atoms. Examples of the olefin monomer include vinyl acetate, vinyl alcohol, acrylic acid, methacrylic acid, methyl acrylate, and methyl methacrylate. In the copolymer of ethylene and 1-olefin monomer, and the copolymer of ethylene and non-olefin monomer having only carbon, oxygen and hydrogen atoms in the functional group, the ethylene content is 70 mol. % Or more is preferable, and 80 to 97 mol% is more preferable.
そして、本発明において高密度ポリエチレンとは、上記エチレン系樹脂のうち、密度が０．９４２ｇ／ｃｍ3 以上のものをいう。なお、エチレン系樹脂の密度は、ＪＩＳ Ｋ７１１２：１９９９「プラスチック−非発泡プラスチックの密度及び比重の測定方法」にて規定されたＡ法（水中置換法）を用いて測定されたものをいう。 In the present invention, the high-density polyethylene refers to those having a density of 0.942 g / cm 3 or more among the ethylene resins. In addition, the density of ethylene-type resin means what was measured using A method (underwater substitution method) prescribed | regulated in JIS K7112: 1999 "The measurement method of the density of non-foaming plastics and specific gravity".
次に、本発明の熱成形用エチレン系樹脂発泡シートが、密度が０．９４５〜０．９７０ｇ／ｃｍ 3 の高密度ポリエチレンを７０〜８５重量％含有し且つ１９０℃におけるダイスェルが１．５５〜１．９０であるエチレン系樹脂からなる場合について説明する。 Next, the ethylene-based resin foam sheet for thermoforming of the present invention contains 70 to 85 % by weight of high density polyethylene having a density of 0.945 to 0.970 g / cm 3 and a die shell at 190 ° C. of 1.55 to 55% by weight. The case where it consists of ethylene-type resin which is 1.90 is demonstrated.
エチレン系樹脂中における高密度ポリエチレンの含有量は、少ないと、熱成形用エチレン系樹脂発泡シートの機械的強度及び耐熱性が低下する一方、多いと、高密度ポリエチレン以外のエチレン系樹脂を含有させて、熱成形用エチレン系樹脂発泡シートの製造時における押出性及び熱成形用エチレン系樹脂発泡シートの熱成形性を向上させようとした効果が発現しないので、７０〜８５重量％に限定される。 If the content of the high-density polyethylene in the ethylene-based resin is small, the mechanical strength and heat resistance of the ethylene-based resin foam sheet for thermoforming will decrease, whereas if it is large, an ethylene-based resin other than the high-density polyethylene will be contained. Te, the effect of an attempt to improve the extrudability and thermoforming of ethylene resin foam sheet for thermoforming in the manufacture of ethylene-based resin foam sheet for thermoforming is not expressed, Ru limited to 70-85 wt% .
そして、高密度ポリエチレンの密度は、低いと、熱成形用エチレン系樹脂発泡シートの機械的強度や耐熱性が低下することがあり、例えば、熱成形用エチレン系樹脂発泡シートを食品容器に熱成形して用いた場合には、熱成形用エチレン系樹脂発泡シートの見掛け密度を大きくする必要があるために熱成形用エチレン系樹脂発泡シートの軽量性が低下したり、或いは、電子レンジにて加熱した際に熱成形用エチレン系樹脂発泡シートが変形することがあるので、０．９４５ｇ／ｃｍ3 以上に限定され、０．９５０ｇ／ｃｍ3 以上が好ましいが、大きいと、エチレン系樹脂の発泡性や得られる熱成形用エチレン系樹脂発泡シートの熱成形性が低下することがあるので、０．９７０ｇ／ｃｍ3 以下に限定され、０．９６５ｇ／ｃｍ3 以下が好ましい。 The density of the high density polyethylene, low when, the mechanical strength and heat resistance of the ethylene-based resin foam sheet for thermoforming is reduced, for example, thermoforming the ethylene-based resin foam sheet for thermoforming into food containers and when used in the light weight is lowered ethylene-based resin foam sheet for thermoforming due to the need to increase the apparent density of the ethylene-based resin foam sheet for thermoforming, or heated in a microwave oven In this case, the foamed ethylene-based resin sheet for thermoforming may be deformed, so it is limited to 0.945 g / cm 3 or more, preferably 0.950 g / cm 3 or more . Ya the heat moldability of the heat molding the ethylene-based resin foam sheet obtained may decrease, limited to 0.970 g / cm 3 or less, preferably 0.965 g / cm 3 or less
又、エチレン系樹脂としては、密度が０．９４５〜０．９７０ｇ／ｃｍ 3 の高密度ポリエチレン７０〜８５重量％と、密度が０．９１５〜０．９３０ｇ／ｃｍ3 のエチレン系樹脂１５〜３０重量％とからなることが好ましく、０．９５０〜０．９７０ｇ／ｃｍ3 の高密度ポリエチレン７０〜８５重量％と、０．９１５〜０．９２５ｇ／ｃｍ3 のエチレン系樹脂１５〜３０重量％とからなることが好ましい。 As the ethylene-based resin, a high density polyethylene 70-85% by weight of the density 0.945~0.970g / cm 3, ethylene-based resins 15-30 having a density of 0.915~0.930g / cm 3 it is preferably made of a percent by weight, from 0.950 to 0.970 and high density polyethylene 70-85% by weight of g / cm 3, 0.915~0.925g / cm 3 of ethylene-based resin 15 to 30 wt% It is preferable to consist of.
これは、高密度ポリエチレンは、機械的強度及び耐熱性に優れている反面、発泡性に劣る一方、密度が低いエチレン系樹脂は、押出発泡性及び熱成形性に優れている反面、機械的強度及び耐熱性に劣ることから、高密度ポリエチレンと、密度が所定範囲内にある低密度なエチレン系樹脂とを併用することによって、互いの欠点を補完しつつ両者の有する特性を効果的に発現させることができるからである。 This is because high-density polyethylene is excellent in mechanical strength and heat resistance, but is inferior in foamability, while low-density ethylene resin is excellent in extrusion foamability and thermoformability, but mechanical strength. In combination with high-density polyethylene and low-density ethylene resin having a density within a predetermined range, the characteristics of both are effectively expressed while complementing each other's drawbacks. Because it can.
そして、高密度ポリエチレンを６０〜９５重量％含有するエチレン系樹脂の１９０℃におけるダイスェルは１．５５以上に限定され、１．６５以上が好ましく、１．７０以上がより好ましい。これは、エチレン系樹脂の１９０℃におけるダイスェルが小さいと、押出発泡時の気泡安定性が低下して破泡が生じ、熱成形用エチレン系樹脂発泡シートの独立気泡率が低下したり、或いは、熱成形用エチレン系樹脂発泡シートの表面平滑性が低下するからであり、更に、熱成形用エチレン系樹脂発泡シートを製造する際に、サーキュラダイとマンドレルとの間で発泡シートが垂れ下がったり或いは切断し易くなり、幅の広い発泡シートへの対応が困難となるからである。加えて、得られる熱成形用エチレン系樹脂発泡シートの熱成形時の温度範囲が狭くなり、伸び不良などが原因となって良好な成形品を得ることができないからである。 And the die shell in 190 degreeC of the ethylene-type resin containing 60 to 95 weight% of high density polyethylene is limited to 1.55 or more, 1.65 or more are preferable and 1.70 or more are more preferable. This is because if the die shell at 190 ° C. of the ethylene-based resin is small, the bubble stability at the time of extrusion foaming is reduced and foam breakage occurs, and the closed cell rate of the ethylene-based resin foam sheet for thermoforming is reduced, or This is because the surface smoothness of the ethylene-based resin foam sheet for thermoforming decreases, and when the ethylene-based resin foam sheet for thermoforming is manufactured, the foam sheet hangs down or is cut between the circular die and the mandrel. This is because it becomes difficult to cope with a wide foam sheet. In addition, the temperature range at the time of thermoforming of the obtained ethylene-based resin foam sheet for thermoforming becomes narrow, and a good molded product cannot be obtained due to poor elongation or the like.
しかしながら、エチレン系樹脂の１９０℃におけるダイスェルは、大きすぎると、熱成形用エチレン系樹脂発泡シートの熱成形時の収縮が大きいと共に伸びが低くなるために所望形状への熱成形が安定的に且つ正確に行なうことができないことがあるので、１．９０以下に限定され、１．８０以下が好ましい。 However, if the die shell at 190 ° C. of the ethylene-based resin is too large, the thermoforming ethylene-based resin foam sheet has a large shrinkage at the time of thermoforming and has a low elongation. Since it may not be performed accurately, it is limited to 1.90 or less, and preferably 1.80 or less.
なお、エチレン系樹脂の１９０℃におけるダイスェルは、ＪＩＳ Ｋ７１９９：１９９９「プラスチック−キャピラリーレオメータ及びスリットダイレオメーターによるプラスチックの流れ特性試験方法」に記載の方法によって測定されたものをいう。なお、エチレン系樹脂の１９０℃におけるダイスェルは、東洋精機製作所社から商品名「ＰＭＤ−Ｃ」で販売されているキャピログラフを用いて測定することができる。具体的には、キャピログラフのシリンダ中に測定試料となるエチレン系樹脂を供給して１９０℃に加熱溶融し、この加熱溶融されたエチレン系樹脂をキャピラリーダイ（内径：２．０９５ｍｍ、長さ：８ｍｍ、流入角度：９０°）からピストン降下速度１０ｍｍ／分の一定速度で紐状に押出す。そして、この紐状物の直径を１９０℃にて測定し、下記式に基づいてエチレン系樹脂の１９０℃におけるダイスェルを算出する。
エチレン系樹脂の１９０℃におけるダイスェル
＝紐状物の直径（ｍｍ）／キャピラリーダイの内径（ｍｍ）
In addition, the die shell at 190 ° C. of the ethylene-based resin refers to that measured by the method described in JIS K7199: 1999 “Plastic-capillary rheometer and plastic flow characteristic test method using slit direometer”. The die shell at 190 ° C. of the ethylene-based resin can be measured using a capillograph sold by Toyo Seiki Seisakusho under the trade name “PMD-C”. Specifically, an ethylene-based resin as a measurement sample is supplied into a capillograph cylinder and heated and melted to 190 ° C., and this heated and melted ethylene-based resin is connected to a capillary die (inner diameter: 2.095 mm, length: 8 mm). , The inflow angle: 90 °) and the piston is extruded in a string shape at a constant speed of 10 mm / min. And the diameter of this string-like thing is measured at 190 degreeC, and the die shell in 190 degreeC of ethylene-type resin is computed based on a following formula.
Die shell of ethylene resin at 190 ° C
= Diameter of string-like object (mm) / Inner diameter of capillary die (mm)
そして、熱成形用エチレン系樹脂発泡シートの見掛け密度は、小さいと、熱成形用エチレン系樹脂発泡シートの機械的強度が低下する一方、大きいと、熱成形用エチレン系樹脂発泡シートの断熱性、軽量性及び柔軟性が低下するので、０．１０〜０．８０ｇ／ｃｍ3 に限定され、０．１５〜０．６０ｇ／ｃｍ3 が好ましく、０．２０〜０．５０ｇ／ｃｍ3 がより好ましく、０．２０〜０．４５ｇ／ｃｍ3 が特に好ましい。 The apparent density of the ethylene-based resin foam sheet for thermoforming is small when, while the mechanical strength of the ethylene-based resin foam sheet for thermoforming is lowered, large when heat insulation of ethylene-based resin foam sheet for thermoforming, lightweight and flexibility is reduced, limited to 0.10 ~0.80g / cm 3, preferably 0.15~0.60g / cm 3, more preferably 0.20~0.50g / cm 3 0.20 to 0.45 g / cm 3 is particularly preferable.
なお、熱成形用エチレン系樹脂発泡シートの見掛け密度は、熱成形用エチレン系樹脂発泡シートの任意の部分から該発泡シートをその厚み方向の全長に亘って切り込むことによって、一辺が１００ｍｍの平面正方形状の試験片を３個、切り出し、各試験片の体積及び重量を測定する。そして、各試験片の重量を体積で除すことによって各試験片の密度を算出し、各試験片の密度の相加平均値を熱成形用エチレン系樹脂発泡シートの見掛け密度とする。 Incidentally, the apparent density of the ethylene-based resin foam sheet for thermoforming, by from any part of the ethylene-based resin foam sheet for thermoforming cut over the foamed sheet the entire length in the thickness direction, a side 100mm planar square Three test pieces are cut out, and the volume and weight of each test piece are measured. Then, the density of each test piece is calculated by dividing the weight of each test piece by the volume, and the arithmetic average value of the density of each test piece is taken as the apparent density of the ethylene-based resin foam sheet for thermoforming .
又、熱成形用エチレン系樹脂発泡シートの厚みは、薄いと、熱成形用エチレン系樹脂発泡シートの機械的強度及び断熱性が低下する一方、厚いと、熱成形用エチレン系樹脂発泡シートの成形性が低下するので、０．５〜５．０ｍｍに限定され、０．６〜３．０ｍｍが好ましい。 The thickness of the ethylene-based resin foam sheet for thermoforming, when thin, whereas the mechanical strength and heat insulating properties of the ethylene-based resin foam sheet for thermoforming is lowered, thick of an ethylene-based resin foam sheet molding for thermoforming Therefore, the thickness is limited to 0.5 to 5.0 mm, and preferably 0.6 to 3.0 mm.
更に、熱成形用エチレン系樹脂発泡シートの連続気泡率は、５０％以下に限定され、３０％以下が好ましく、２０％以下がより好ましい。これは、熱成形用エチレン系樹脂発泡シートの連続気泡率が高いと、熱成形用エチレン系樹脂発泡シートの機械的強度や表面平滑性が低下すると共に、熱成形用エチレン系樹脂発泡シートを熱成形した際に熱成形用エチレン系樹脂発泡シートの表面に凹凸が発生して表面平滑性が低下する虞れがある上に、熱成形用エチレン系樹脂発泡シートの伸びが低下して破れが発生する虞れがあるからである。 Furthermore, the open cell ratio of the ethylene-based resin foam sheet for thermoforming is limited to 50% or less, preferably 30% or less, and more preferably 20% or less. This is because when the open cell ratio of the ethylene-based resin foam sheet for thermoforming is high, heat with the ethylene-based resin foam sheet for thermoforming mechanical strength and surface smoothness of the ethylene-based resin foam sheet for thermoforming is reduced on the surface smoothness irregularities thermoforming ethylene resin foam surface of the sheet upon shaping occurs and there is a possibility to deteriorate, break occurs elongation of the ethylene-based resin foam sheet for thermoforming is lowered It is because there is a possibility of doing.
なお、熱成形用エチレン系樹脂発泡シートの連続気泡率は、ＡＳＴＭ Ｄ−２８５６−８７に準拠して１−１／２−１気圧法にて測定されたものをいう。具体的には、熱成形用エチレン系樹脂発泡シートを一辺２５ｍｍの平面正方形状に切断し、この切断片を厚み方向に複数枚重ね合わせて厚みが約２５ｍｍの試験片を作製する。この要領で５個の試験片を作製し、各試験片の連続気泡率を空気比較式比重計（東京サイエンス社製 商品名「１０００型」）を用いて、１−１／２−１気圧法により測定し、その相加平均値を熱成形用エチレン系樹脂発泡シートの連続気泡率とする。 In addition, the open cell rate of the ethylene-type resin foam sheet for thermoforming refers to what was measured by the 1-1 / 2-1 atmospheric pressure method based on ASTM D-2856-87. Specifically, an ethylene-based resin foam sheet for thermoforming is cut into a planar square shape with a side of 25 mm, and a plurality of the cut pieces are stacked in the thickness direction to produce a test piece with a thickness of about 25 mm. Five test pieces were prepared in this manner, and the open cell ratio of each test piece was determined by using the air comparison type hydrometer (trade name “1000 type” manufactured by Tokyo Science Co., Ltd.). The arithmetic mean value is defined as the open cell ratio of the ethylene-based resin foam sheet for thermoforming .
又、熱成形用エチレン系樹脂発泡シートの中心線表面粗さ（Ｒａ）は、大きいと、熱成形用エチレン系樹脂発泡シートの外観が低下すると共に、熱成形用エチレン系樹脂発泡シートを熱成形して食品容器として用いた後にこの食品容器を再利用する際に、熱成形用エチレン系樹脂発泡シートの表面に形成された凹部に汚れが進入して洗浄が困難となることがあるので、８μｍ以下が好ましく、５μｍ以下がより好ましい。 Also, for thermoforming ethylene resin foam center line surface roughness of the sheet (Ra) is greater when, with the appearance of the ethylene-based resin foam sheet for thermoforming is lowered, thermoforming ethylene-based resin foam sheet for thermoforming When the food container is reused after being used as a food container, dirt may enter the recesses formed on the surface of the thermoforming ethylene-based resin foam sheet, making it difficult to clean. The following is preferable, and 5 μm or less is more preferable.
ここで、熱成形用エチレン系樹脂発泡シートの中心線表面粗さ（Ｒａ）は下記の要領で測定されたものをいう。即ち、熱成形用エチレン系樹脂発泡シートの表裏面の表面粗さをそれぞれ、表面粗さ測定器を用いて、カットオフ値２．５μｍ、測定長さ１２．５ｍｍの条件下にて測定し、これら測定値から熱成形用エチレン系樹脂発泡シートの表裏面の中心線表面粗さ（Ｒａ）をそれぞれ算出した。そして、熱成形用エチレン系樹脂発泡シートの表裏面の中心線表面粗さ（Ｒａ）のうち、大きい方の中心線表面粗さ（Ｒａ）を熱成形用エチレン系樹脂発泡シートの中心線表面粗さ（Ｒａ）とする。なお、熱成形用エチレン系樹脂発泡シートの中心線表面粗さ（Ｒａ）は、例えば、東京精密社から商品名「ハンディサーフＥ−３０Ａ」で市販されている測定装置を用いて測定することができる。 Here, the centerline surface roughness (Ra) of the ethylene-based resin foam sheet for thermoforming refers to that measured in the following manner. That is, the surface roughness of the front and back surfaces of the ethylene-based resin foam sheet for thermoforming was measured using a surface roughness measuring instrument under conditions of a cutoff value of 2.5 μm and a measurement length of 12.5 mm, From these measured values, the center line surface roughness (Ra) of the front and back surfaces of the ethylene-based resin foam sheet for thermoforming was calculated. And among the centerline surface roughness (Ra) of the front and back surfaces of the ethylene-based resin foam sheet for thermoforming , the larger centerline surface roughness (Ra) is the centerline surface roughness of the ethylene-based resin foam sheet for thermoforming. (Ra). In addition, the centerline surface roughness (Ra) of the ethylene-based resin foam sheet for thermoforming can be measured, for example, using a measuring apparatus commercially available from Tokyo Seimitsu Co., Ltd. under the trade name “Handy Surf E-30A”. it can.
更に、上記熱成形用エチレン系樹脂発泡シートの少なくとも一面に熱可塑性樹脂フィルムを積層一体化させてることによって、熱成形用エチレン系樹脂発泡シートの表面平滑性の向上を図ってもよい。 Furthermore, the fact that the thermoplastic resin film is integrally laminated on at least one surface of the ethylene-based resin foam sheet for the thermoforming, also possible to improve the surface smoothness of the ethylene-based resin foam sheet for thermoforming.
このような熱可塑性樹脂フィルムとしては、例えば、上記エチレン系樹脂からなるフィルム、プロピレンの単独重合体やプロピレンと１−オレフィン単量体との共重合体などのプロピレン系樹脂からなるフィルムなどのオレフィン系樹脂フィルムが挙げられ、エチレン系樹脂フィルムが好ましい。なお、１−オレフィン単量体としては、エチレン、１−ブテン、１−ヘキセン、１−オクテン、４−メチル−１−ペンテンなどが挙げられる。 Examples of such a thermoplastic resin film include olefins such as a film made of the above-mentioned ethylene resin, a film made of a propylene resin such as a propylene homopolymer or a copolymer of propylene and a 1-olefin monomer. Based resin films, and ethylene resin films are preferred. Examples of the 1-olefin monomer include ethylene, 1-butene, 1-hexene, 1-octene, 4-methyl-1-pentene and the like.
続いて、上記熱成形用エチレン系樹脂発泡シートの製造方法を説明する。この熱成形用エチレン系樹脂発泡シートの製造方法としては、１）密度が０．９４５〜０．９７０ｇ／ｃｍ 3 の高密度ポリエチレンを７０〜８５重量％含有し且つ所定範囲内のダイスェルを有するエチレン系樹脂を押出機に供給して発泡剤の存在下にて溶融混練し、押出機に取り付けたサーキュラダイから押出発泡させて円筒状の発泡成形体を製造し、この発泡成形体を径方向に拡径させつつマンドレルに供給して冷却し、しかる後、発泡成形体を押出方向に連続的に切断、展開して熱成形用エチレン系樹脂発泡シートを製造する方法、２）密度が０．９４５〜０．９７０ｇ／ｃｍ 3 の高密度ポリエチレンを７０〜８５重量％含有し且つ所定範囲内のダイスェルを有するエチレン系樹脂を押出機に供給して発泡剤の存在下にて溶融混練し、押出機に取り付けたＴダイからシート状に押出発泡させて熱成形用エチレン系樹脂発泡シートを製造する方法などが挙げられる。 Then, the manufacturing method of the said ethylene-type resin foam sheet for thermoforming is demonstrated. As a method for producing this ethylene-based resin foam sheet for thermoforming , 1) ethylene containing 70 to 85 % by weight of high density polyethylene having a density of 0.945 to 0.970 g / cm 3 and having a die shell within a predetermined range. Resin is supplied to an extruder, melted and kneaded in the presence of a foaming agent, and extruded and foamed from a circular die attached to the extruder to produce a cylindrical foam molded body. A method for producing an ethylene-based resin foam sheet for thermoforming by continuously cutting and developing the foamed molded product in the extrusion direction after being supplied to a mandrel while expanding the diameter and cooling, and 2) a density of 0.945. ~0.970g / cm 3 of a high-density polyethylene by feeding ethylene-based resin having a Daisueru within and a predetermined range containing 70-85 wt% in the extruder and melt-kneaded in the presence of a blowing agent, And a method in which a T-die attached to extruder by extrusion foaming the sheet to produce the ethylene-based resin foam sheet for thermoforming and the like.
上記１）２）の何れの方法にあっても、押出機から吐出された直後のエチレン系樹脂は、発泡すると共に樹脂自体も膨張することから、円筒状発泡成形体の周方向或いはシートの幅方向にコルゲーションと称される波打ち現象が見られ、このコルゲーションが熱成形用エチレン系樹脂発泡シートに残存したままであると、熱成形用エチレン系樹脂発泡シートの品質が不均一となったり或いは熱成形用エチレン系樹脂発泡シートの用途が制限される虞れがあるので、熱成形用エチレン系樹脂発泡シートからコルゲーションを除去することが好ましい。 In any of the above methods 1) and 2), since the ethylene-based resin immediately after being discharged from the extruder expands and the resin itself expands, the circumferential direction of the cylindrical foamed molded product or the sheet width observed phenomenon wavy called corrugation direction, this corrugation is left remaining in the ethylene-based resin foam sheet for thermoforming, or the quality of the ethylene-based resin foam sheet for thermoforming may become uneven heat Since the use of the molding ethylene-based resin foam sheet may be limited, it is preferable to remove corrugation from the thermoforming ethylene-based resin foam sheet.
そして、上記１）の製造方法は、円筒状発泡成形体を径方向に拡径させて発泡成形体の周方向に延伸させていることから、発泡成形体に発生したコルゲーションを除去し易い。従って、上記１）の製造方法は、コルゲーションが発生し易い、高発泡倍率の熱成形用エチレン系樹脂発泡シートの製造に適しており、具体的には、見掛け密度が０．１１〜０．５０ｇ／ｃｍ3 の熱成形用エチレン系樹脂発泡シートの製造に適しており、見掛け密度が０．１１〜０．３５ｇ／ｃｍ3 の熱成形用エチレン系樹脂発泡シートの製造に更に適している。 And the manufacturing method of said 1) is easy to remove the corrugation which generate | occur | produced in the foaming molding since the cylindrical foaming molding is diameter-expanded and extended in the circumferential direction of the foaming molding. Therefore, the production method of the above 1), the corrugation is likely to occur, it is suitable for the production of ethylene-based resin foam sheet for thermoforming a high expansion ratio, specifically an apparent density of 0.11~0.50g / cm 3 of which suitable for the production of ethylene-based resin foam sheet for thermoforming, the apparent density is more suitable for the production of heat molding the ethylene-based resin foam sheet of 0.11～0.35G / cm 3.
又、押出機に取り付けたサーキュラダイのリップ部における内ダイの外径と、マンドレルの押出機側先端の外径との比は、小さいと、円筒状発泡成形体に発生したコルゲーションを除去することができないことがある一方、大きいと、発泡成形体が破断することがあるので、２．００以上が好ましく、２．２５以上がより好ましく、２．５０以上が特に好ましく、大きすぎると、円筒状発泡成形体が裂けたり或いはちぎれたりすることがあるので、４．０以下が好ましく、３．５以下がより好ましい。 In addition, if the ratio of the outer diameter of the inner die at the lip portion of the circular die attached to the extruder and the outer diameter of the mandrel on the extruder side is small, the corrugation generated in the cylindrical foamed molded body should be removed. On the other hand, if it is large, the foamed molded product may be broken. Therefore, it is preferably 2.00 or more, more preferably 2.25 or more, particularly preferably 2.50 or more. Since the foamed molded product may be torn or torn, 4.0 or less is preferable, and 3.5 or less is more preferable.
そして、上記１）の製造方法において、得られる熱成形用エチレン系樹脂発泡シートの平均気泡径が０．２０〜１．００ｍｍとなるように調整することが好ましく、０．２５〜０．８０ｍｍとなるように調整することがより好ましく、０．２５〜０．６０ｍｍとなるように調整することが特に好ましい。なお、熱成形用エチレン系樹脂発泡シートの平均気泡径は、後述する物理型発泡剤と、気泡核剤としての作用も奏する後述の熱分解型発泡剤とを併用したり、或いは、気泡核剤の添加によって制御することができ、具体的には、熱成形用エチレン系樹脂発泡シートの製造時、エチレン系樹脂１００重量部に対して気泡核剤０．５〜３．０重量部添加するのが好ましい。このような気泡核剤としては、例えば、タルク、マイカなどが挙げられる。 And in the manufacturing method of said 1), it is preferable to adjust so that the average cell diameter of the ethylene-type resin foam sheet for thermoforming obtained may be 0.20-1.00 mm, and it is 0.25-0.80 mm. It is more preferable to adjust so that it may become, and it is especially preferable to adjust so that it may become 0.25-0.60 mm. The average cell diameter of the ethylene-based resin foam sheet for thermoforming may be a combination of a physical foaming agent described later and a thermal decomposition foaming agent described later that also acts as a cell nucleating agent, or a cell nucleating agent. Specifically, 0.5 to 3.0 parts by weight of the cell nucleating agent is added to 100 parts by weight of the ethylene resin when manufacturing the ethylene-based resin foam sheet for thermoforming . Is preferred. Examples of such bubble nucleating agents include talc and mica.
これは、熱成形用エチレン系樹脂発泡シートの平均気泡径が小さいと、気泡膜が薄くなり、円筒状発泡成形体を径方向に拡径させる際に気泡破れが発生するなどして熱成形用エチレン系樹脂発泡シートの表面平滑性の低下を生じることがある一方、大きいと、熱成形用エチレン系樹脂発泡シートの表面平滑性が低下することがあるからである。 This is because when the average cell diameter of the ethylene-based resin foam sheet for thermoforming is small, the cell membrane becomes thin, and bubble breakage occurs when expanding the diameter of the cylindrical foamed molded product . This is because the surface smoothness of the ethylene-based resin foamed sheet may be lowered, whereas if it is large, the surface smoothness of the ethylene-based resin foamed sheet for thermoforming may be lowered.
更に、上記１）の製造方法において、熱成形用エチレン系樹脂発泡シートにおける押出方向（ＭＤ）の平均気泡径と、平均気泡径との比（ＭＤの平均気泡径／平均気泡径）が０．７０〜１．６０となるように調整することが好ましい。 Furthermore, in the production method of 1) above, the ratio of the average cell diameter in the extrusion direction (MD) to the average cell size (MD average cell diameter / average cell diameter) in the ethylene-based resin foam sheet for thermoforming is 0. It is preferable to adjust so that it may become 70-1.60.
一方、上記１）の製造方法において、熱成形用エチレン系樹脂発泡シートにおける発泡シート表面に沿い且つ押出方向に直交する方向（ＴＤ）の平均気泡径と、平均気泡径との比（ＴＤの平均気泡径／平均気泡径）が１．１０〜２．００となるように調整することが好ましい。 On the other hand, in the production method of 1) above, the ratio of the average cell diameter in the direction (TD) along the foamed sheet surface in the ethylene-based resin foamed sheet for thermoforming and orthogonal to the extrusion direction (average of TD) It is preferable to adjust so that (bubble diameter / average bubble diameter) is 1.10 to 2.00.
これは、熱成形用エチレン系樹脂発泡シートにおけるＭＤ又はＴＤの平均気泡径と、平均気泡径との比（ＭＤ又はＴＤの平均気泡径／平均気泡径）は、小さいと、円筒状の発泡成形体の延伸が不充分となって発泡成形体に発生したコルゲーションを除去することができないことがある一方、大きいと、熱成形用エチレン系樹脂発泡シートの製造時に破泡して熱成形用エチレン系樹脂発泡シートの連続気泡率が大きくなることがあるからである。なお、熱成形用エチレン系樹脂発泡シートにおけるＭＤ又はＴＤの平均気泡径と、平均気泡径との比（ＭＤ又はＴＤの平均気泡径／平均気泡径）は、サーキュラダイのリップ部における内ダイの外径と、マンドレルの押出機側先端の外径との比や、サーキュラダイのスリットクリアランスを調整することによって制御することができる。 This is because when the ratio of the average cell diameter of MD or TD to the average cell diameter (average cell diameter of MD or TD / average cell diameter) in the ethylene-based resin foam sheet for thermoforming is small, it is a cylindrical foam molding. while becomes insufficient stretching of the body may not be able to remove the corrugations generated in the foamed molded product, large when, thermoforming ethylene with foam breaking during the production of the ethylene-based resin foam sheet for thermoforming This is because the open cell ratio of the resin foam sheet may increase. The ratio of the average cell diameter of MD or TD in the ethylene-based resin foam sheet for thermoforming and the average cell diameter (average cell diameter of MD or TD / average cell diameter) is the value of the inner die in the lip portion of the circular die. It can be controlled by adjusting the ratio between the outer diameter and the outer diameter of the mandrel on the extruder side and the slit clearance of the circular die.
なお、熱成形用エチレン系樹脂発泡シートの平均気泡径は、下記の要領で測定されたものをいう。即ち、熱成形用エチレン系樹脂発泡シートの平均気泡径は、ＡＳＴＭ Ｄ２８４２−６９の試験方法に準拠して測定された平均弦長に基づいて算出されたものをいう。具体的には、熱成形用エチレン系樹脂発泡シートを、平均気泡径を測定したい方向に沿った面で切断し、その切断面のうちの外周部を除いた中央部分を任意に４箇所、走査型電子顕微鏡を用いて拡大して電子顕微鏡写真を撮影する。 In addition, the average cell diameter of the ethylene-type resin foam sheet for thermoforming says what was measured in the following way. That is, the average cell diameter of the ethylene-based resin foam sheet for thermoforming refers to that calculated based on the average chord length measured according to the test method of ASTM D2842-69. Specifically, the ethylene-based resin foam sheet for thermoforming is cut along a plane along the direction in which the average cell diameter is desired to be measured, and the central portion excluding the outer peripheral portion of the cut surface is arbitrarily scanned at four locations. Magnify using a scanning electron microscope and take an electron micrograph.
次に、撮影した各写真に写真上長さ６０ｍｍの直線を、平均気泡径を測定したい方向に描き、この直線上にある気泡数から、気泡の平均弦長ｔを下記式１に基づいて算出する。直線は各写真毎に６本づつ描き、各直線ごとに平均弦長ｔを算出し、各写真毎に平均弦長ｔの相加平均を算出し、この相加平均値を気泡の平均弦長ｔとする。なお、直線上に長さ６０ｍｍの直線を描けない場合には、長さ２０ｍｍ或いは３０ｍｍの直線を写真上に描き、この直線上にある気泡数を測定し、長さ６０ｍｍの直線上にある気泡数に比例換算する。
平均弦長ｔ＝６０／（気泡数×写真の倍率）・・・式１
Next, a straight line with a length of 60 mm is drawn on each photograph taken in the direction in which the average bubble diameter is to be measured, and the average chord length t of the bubbles is calculated based on the following formula 1 from the number of bubbles on the straight line. To do. 6 straight lines are drawn for each photo, the average chord length t is calculated for each straight line, the arithmetic average of the average chord length t is calculated for each photo, and this arithmetic average value is calculated as the average chord length of bubbles. Let t. If a straight line with a length of 60 mm cannot be drawn on the straight line, a straight line with a length of 20 mm or 30 mm is drawn on the photograph, the number of bubbles on the straight line is measured, and a bubble on the straight line with a length of 60 mm is measured. Convert proportionally to a number.
Average chord length t = 60 / (number of bubbles × photo magnification) Formula 1
そして、下記式２により気泡径Ｄを算出し、各写真の気泡径Ｄの相加平均を熱成形用エチレン系樹脂発泡シートの所望方向の平均気泡径とする。
気泡径Ｄ＝平均弦長ｔ／０．６１６・・・式２
And the bubble diameter D is calculated by following formula 2, and let the arithmetic mean of the bubble diameter D of each photograph be the average bubble diameter of the desired direction of the ethylene-type resin foam sheet for thermoforming .
Bubble diameter D = average chord length t / 0.616 Equation 2
なお、熱成形用エチレン系樹脂発泡シートの平均気泡径は、上述の要領で、ＭＤの平均気泡径、ＴＤの平均気泡径、及び、ＭＤ及びＴＤに直交する方向（ＶＤ）の平均気泡径をそれぞれ測定し、ＭＤ、ＴＤ及びＶＤの平均気泡径を相加平均することによって算出することができる。 In addition, the average cell diameter of the ethylene-based resin foam sheet for thermoforming is the average cell size of MD, the average cell diameter of TD, and the average cell diameter in the direction perpendicular to MD and TD (VD) in the manner described above. It can be calculated by measuring each and averaging the average bubble diameter of MD, TD and VD.
又、上記１）の製造方法で用いられる発泡剤としては、従来から発泡シートの製造に用いられているものであれば、特に限定されないが、熱分解型発泡剤のみを発泡剤として用いると、低い見掛け密度に発泡させにくく、しかも、熱分解型発泡剤は気泡核剤としても作用することから、得られる熱成形用エチレン系樹脂発泡シートの気泡が微細化し易くなり、気泡が微細化して気泡膜が薄くなると、円筒状発泡成形体を径方向に拡径させる際に気泡破れが発生したり或いは樹脂の伸び不良が原因となって、熱成形用エチレン系樹脂発泡シートの表面平滑性の低下を生じることがある。従って、上記１）の製造方法で用いられる発泡剤としては、物理型発泡剤が好ましく、物理型発泡剤と熱分解型発泡剤とを併用することがより好ましい。 In addition, the foaming agent used in the production method 1) is not particularly limited as long as it is conventionally used in the production of foamed sheets, but when only a pyrolytic foaming agent is used as the foaming agent, It is difficult to foam to a low apparent density, and since the pyrolytic foaming agent also acts as a cell nucleating agent, it is easy to make the bubbles in the resulting thermoplastic resin foam sheet for thermoforming fine, and the bubbles become finer. When the film is thinned, the surface smoothness of the ethylene-based resin foam sheet for thermoforming deteriorates due to the occurrence of bubble breakage or poor resin elongation when the cylindrical foam molded article is radially expanded. May occur. Accordingly, the foaming agent used in the production method 1) is preferably a physical foaming agent, and more preferably a physical foaming agent and a pyrolytic foaming agent are used in combination.
このような物理型発泡剤としては、例えば、ブタン、ペンタンなどの炭化水素又はこれらのハロゲン化物、ジメチルエーテルなどのエーテル類、アルコール、ケトン、窒素、二酸化炭素などの無機ガスなどが挙げられる。なお、物理型発泡剤の添加量は、エチレン系樹脂１００重量部に対して０．０５〜３．０重量部が好ましい。 Examples of such a physical foaming agent include hydrocarbons such as butane and pentane, halides thereof, ethers such as dimethyl ether, inorganic gases such as alcohol, ketone, nitrogen and carbon dioxide. In addition, the addition amount of the physical foaming agent is preferably 0.05 to 3.0 parts by weight with respect to 100 parts by weight of the ethylene-based resin.
そして、熱分解型発泡剤としては、例えば、アゾジカルボンアミド、ベンゼンスルホニルヒドラジド、ジニトロソペンタメチレンテトラミン、トルエンスルホニルヒドラジド、４，４−オキシビス（ベンゼンスルホニルヒドラジド）、重曹とクエン酸との混合物などが挙げられ、アゾジカルボンアミド、重曹とクエン酸との混合物が好ましい。なお、熱分解型発泡剤の添加量は、エチレン系樹脂１００重量部に対して０．０５〜２重量部が好ましい。 Examples of the pyrolytic foaming agent include azodicarbonamide, benzenesulfonylhydrazide, dinitrosopentamethylenetetramine, toluenesulfonylhydrazide, 4,4-oxybis (benzenesulfonylhydrazide), a mixture of sodium bicarbonate and citric acid, and the like. Among them, azodicarbonamide, a mixture of sodium bicarbonate and citric acid is preferable. In addition, the addition amount of the pyrolytic foaming agent is preferably 0.05 to 2 parts by weight with respect to 100 parts by weight of the ethylene-based resin.
一方、上記２）の製造方法は、押出機に取り付けたＴダイから押出発泡させるものであるので、Ｔダイから吐出させた発泡シートを幅方向に大きく延伸させることができないので、発泡シートにコルゲーションを発生させないように、低発泡倍率の熱成形用エチレン系樹脂発泡シートの製造に適しており、具体的には、見掛け密度が０．３０〜０．８０ｇ／ｃｍ3 の熱成形用エチレン系樹脂発泡シートの製造に適しており、見掛け密度が０．４０〜０．８０ｇ／ｃｍ3 の熱成形用エチレン系樹脂発泡シートの製造に更に適している。 On the other hand, since the production method of 2) above involves extrusion foaming from a T die attached to an extruder, the foamed sheet discharged from the T die cannot be stretched greatly in the width direction. Is suitable for the production of an ethylene-based resin foam sheet for thermoforming with a low expansion ratio, specifically, an ethylene-based resin for thermoforming with an apparent density of 0.30 to 0.80 g / cm 3. It is suitable for the production of a foam sheet, and more suitable for the production of an ethylene-based resin foam sheet for thermoforming having an apparent density of 0.40 to 0.80 g / cm 3 .
そして、上記２）の製造方法では、上記１）の製造方法に比較して押出機から吐出した発泡シートの延伸度合いが低いので、得られる熱成形用エチレン系樹脂発泡シートの破泡などに起因した表面平滑性の低下などの問題を生じにくく、熱成形用エチレン系樹脂発泡シートの平均気泡径を小さくすることができる。 And in the manufacturing method of said 2), since the extending | stretching degree of the foamed sheet discharged from the extruder is low compared with the manufacturing method of said 1), it originates in the foam breakage etc. of the ethylene-type resin foam sheet for thermoforming obtained. Thus, problems such as reduced surface smoothness are unlikely to occur, and the average cell diameter of the ethylene-based resin foam sheet for thermoforming can be reduced.
具体的には、得られる熱成形用エチレン系樹脂発泡シートの平均気泡径が０．１０〜０．５０ｍｍとなるように調整することが好ましく、０．１５〜０．４０ｍｍとなるように調整することがより好ましい。なお、熱成形用エチレン系樹脂発泡シートの平均気泡径は、用いられる発泡剤の種類などを調整することによって制御することができる。 Specifically, it is preferable to adjust so that the average cell diameter of the obtained ethylene-based resin foamed sheet for thermoforming may be 0.10 to 0.50 mm, and 0.15 to 0.40 mm. It is more preferable. In addition, the average cell diameter of the ethylene-based resin foam sheet for thermoforming can be controlled by adjusting the type of foaming agent used.
これは、熱成形用エチレン系樹脂発泡シートの平均気泡径が小さいと、熱成形用エチレン系樹脂発泡シートの製造時に連続気泡となり易くなる一方、大きいと、熱成形用エチレン系樹脂発泡シートの表面平滑性が低下することがあるからである。 This is because if the average cell diameter of the ethylene-based resin foam sheet for thermoforming is small, while easily become open cells at the time of manufacture of the heat molding the ethylene-based resin foam sheet, a large of an ethylene-based resin foam surface of the sheet for thermoforming This is because the smoothness may decrease.
更に、上記２）の製造方法において、熱成形用エチレン系樹脂発泡シートにおける押出方向（ＭＤ）の平均気泡径と、平均気泡径との比（ＭＤの平均気泡径／平均気泡径）が１．１０〜２．００となるように調整することが好ましい。 Furthermore, in the production method of 2) above, the ratio of the average cell diameter in the extrusion direction (MD) to the average cell diameter (MD average cell diameter / average cell diameter) in the ethylene-based resin foam sheet for thermoforming is 1. It is preferable to adjust so that it may become 10-2.00.
一方、上記２）の製造方法において、熱成形用エチレン系樹脂発泡シートにおける発泡シート表面に沿い且つ押出方向に直交する方向（ＴＤ）の平均気泡径と、平均気泡径との比（ＴＤの平均気泡径／平均気泡径）が０．７０〜１．１０となるように調整することが好ましい。 On the other hand, in the production method of 2) above, the ratio of the average cell diameter in the direction (TD) along the foamed sheet surface in the ethylene-based resin foamed sheet for thermoforming and orthogonal to the extrusion direction (average of TD) It is preferable to adjust so that (bubble diameter / average bubble diameter) is 0.70 to 1.10.
これは、熱成形用エチレン系樹脂発泡シートにおけるＭＤ又はＴＤの平均気泡径と、平均気泡径との比（ＭＤ又はＴＤの平均気泡径／平均気泡径）は、独立気泡率の高い熱成形用エチレン系樹脂発泡シートを得るための目安となるものであり、（ＭＤ又はＴＤの平均気泡径／平均気泡径）が小さいと、コルゲーションが発生することがある一方、大きいと、熱成形用エチレン系樹脂発泡シートの連続気泡率が大きくなることがあるからである。 This is because the ratio of the average cell diameter of MD or TD to the average cell diameter in the ethylene-based resin foam sheet for thermoforming (average cell diameter of MD or TD / average cell diameter) is for thermoforming with a high closed cell ratio . This is a guideline for obtaining an ethylene-based resin foam sheet. When (MD or TD average cell diameter / average cell diameter) is small, corrugation may occur, whereas when it is large, ethylene-based resin for thermoforming. This is because the open cell ratio of the resin foam sheet may increase.
なお、熱成形用エチレン系樹脂発泡シートの平均気泡径及び所望方向における平均気泡径の測定方法は、上述した要領と同様であるのでその説明を省略する。 In addition, since the measuring method of the average cell diameter of the ethylene-type resin foam sheet for thermoforming and the average cell diameter in a desired direction is the same as the point mentioned above, the description is abbreviate | omitted.
そして、上記２）の製造方法に用いられる発泡剤としては、従来から発泡シートの製造に用いられているものであれば、特に限定されないが、気泡核剤としても作用し、得られる熱成形用エチレン系樹脂発泡シートの気泡が微細となるので、上述の熱分解型発泡剤が好ましい。なお、熱分解型発泡剤の添加量は、エチレン系樹脂１００重量部に対して０．１〜５．０重量部が好ましい。 And as a foaming agent used for the manufacturing method of said 2), if it is conventionally used for manufacture of a foam sheet, it will not specifically limit, It acts also as a cell nucleating agent, For the thermoforming obtained Since the bubbles of the ethylene-based resin foam sheet become fine, the above-described pyrolytic foaming agent is preferable. The addition amount of the pyrolytic foaming agent is preferably 0.1 to 5.0 parts by weight with respect to 100 parts by weight of the ethylene-based resin.
又、熱成形用エチレン系樹脂発泡シートの一面に熱可塑性樹脂フィルムを積層一体化させる方法としては、汎用の方法が用いられ、共押出法、熱ラミネート法、接着剤を用いる方法などが挙げられるが、生産効率が高いことから共押出法が好ましい。 Moreover, as a method of laminating and integrating a thermoplastic resin film on one surface of an ethylene-based resin foam sheet for thermoforming , a general-purpose method is used, and examples thereof include a co-extrusion method, a heat laminating method, and a method using an adhesive. However, the coextrusion method is preferable because of high production efficiency.
具体的には、上記共押出法とは、一の押出機から発泡シートを構成する発泡剤含有エチレン系樹脂を押出すと共に、他の押出機から熱可塑性樹脂フィルムを構成する熱可塑性樹脂を押出し、これらの樹脂を合流ダイに供給して、発泡剤含有エチレン系樹脂の表裏面或いは内外面に熱可塑性樹脂フィルムが積層された積層樹脂とした上で、この積層樹脂を合流ダイ又は合流ダイに連結されたダイから押出発泡させる方法である。 Specifically, the co-extrusion method refers to extruding a foaming agent-containing ethylene resin constituting a foam sheet from one extruder and extruding a thermoplastic resin constituting a thermoplastic resin film from another extruder. Then, after supplying these resins to the merging die and forming a laminated resin in which a thermoplastic resin film is laminated on the front and back surfaces or inner and outer surfaces of the foaming agent-containing ethylene resin, this laminated resin is used as a merging die or merging die This is a method of extrusion foaming from connected dies.
上記共押出法では合流ダイ内において樹脂の流れを安定化させるために、発泡剤含有エチレン系樹脂と熱可塑性樹脂との溶融粘度をできるだけ近づける必要がある。そして、発泡剤含有エチレン系樹脂は押出機内において発泡に適した温度に冷却された上で合流ダイに供給されるが、この発泡適正温度では熱可塑性樹脂の溶融粘度が高すぎることから、熱可塑性樹脂の温度を高く設定して、発泡剤含有エチレン系樹脂と熱可塑性樹脂との溶融粘度を近づける必要がある。 In the coextrusion method, in order to stabilize the flow of the resin in the joining die, it is necessary to make the melt viscosity of the foaming agent-containing ethylene resin and the thermoplastic resin as close as possible. The ethylene-based resin containing the blowing agent is cooled to a temperature suitable for foaming in the extruder and then supplied to the merging die. However, the thermoplastic resin has a melt viscosity that is too high at the proper foaming temperature. It is necessary to set the temperature of the resin high so that the melt viscosity of the foaming agent-containing ethylene resin and the thermoplastic resin approaches.
そのようにすると、従来のエチレン系樹脂では、熱可塑性樹脂との界面の温度が高くなり過ぎて破泡を誘発するといった問題点を生じ、従来のエチレン系樹脂では、エチレン系樹脂発泡シートの一面に共押出法によって熱可塑性樹脂フィルムを積層一体化させるのは困難とされていた。 As a result, the conventional ethylene resin has a problem that the temperature at the interface with the thermoplastic resin becomes too high and induces bubble breakage. In the conventional ethylene resin, one surface of the ethylene resin foam sheet is produced. In addition, it has been difficult to laminate and integrate the thermoplastic resin film by the co-extrusion method.
そこで、本発明では、上述のように、ダイスェルが所定値以上である高密度ポリエチレンのみからなるエチレン系樹脂、或いは、高密度ポリエチレンを所定量含有し且つダイスェルが所定値以上であるエチレン系樹脂を用いることによって、発泡工程における気泡の安定性が向上しており、上述のように、熱可塑性樹脂の温度を高く設定しても、高密度ポリエチレン或いは高密度ポリエチレンを所定量含有するエチレン系樹脂の発泡中に破泡が生じるのを効果的に抑制して良好な発泡性を維持することができ、得られる熱成形用エチレン系樹脂発泡シートの気泡を均一で微細なものとしつつ、この熱成形用エチレン系樹脂発泡シートの一面に熱可塑性樹脂フィルムを効率良く積層一体化することができる。 Therefore, in the present invention, as described above, an ethylene-based resin consisting only of high-density polyethylene having a die shell having a predetermined value or more, or an ethylene-based resin containing a predetermined amount of high-density polyethylene and having a die shell having a predetermined value or more. By using, the stability of the bubbles in the foaming process is improved, and as described above, even if the temperature of the thermoplastic resin is set high, high-density polyethylene or ethylene-based resin containing a predetermined amount of high-density polyethylene is used. and effectively inhibited the foam-breaking from occurring during the foaming can maintain good foaming, uniform air bubbles thermoforming ethylene resin foam sheet obtained with a fine things, this thermoforming A thermoplastic resin film can be efficiently laminated and integrated on one surface of the ethylene-based resin foam sheet.
上述のようにして得られた熱成形用エチレン系樹脂発泡シートは、真空成形法、圧空成形法、真空・圧空成形法などの汎用の熱成形方法を用いて熱成形されて成形品とされるが、真空成形法によって熱成形されることが好ましい。 The ethylene-based resin foam sheet for thermoforming obtained as described above is thermoformed using a general-purpose thermoforming method such as a vacuum forming method, a pressure forming method, or a vacuum / pressure forming method into a molded product. However, it is preferably thermoformed by a vacuum forming method.
そして、熱成形用エチレン系樹脂発泡シートを熱成形して得られた成形品は、多種多様の用途に用いることができ、例えば、食品用容器、工業部品用容器などの各種容器、これら容器内を仕切る仕切材などに用いることができる。 Then, the molded article obtained ethylene-based resin foam sheet for thermoforming and thermoforming, wide it can be used in a variety of applications, for example, food containers, various containers such as industrial parts container, these vessel It can be used as a partitioning material for partitioning.
本発明の熱成形用エチレン系樹脂発泡シートは、密度が０．９４５〜０．９７０ｇ／ｃｍ 3 の高密度ポリエチレンを７０〜８５重量％含有し且つ１９０℃におけるダイスェルが１．５５〜１．９０であるエチレン系樹脂からなると共に、見掛け密度が０．１０〜０．８０ｇ／ｃｍ3 、厚みが０．５〜５．０ｍｍ、連続気泡率が５０％以下であることを特徴とするので、均一で微細な独立気泡を有していると共に熱成形性に優れている。 The ethylene-based resin foam sheet for thermoforming of the present invention contains 70 to 85 % by weight of high density polyethylene having a density of 0.945 to 0.970 g / cm 3 and a die shell at 190 ° C. of 1.55 to 1.90. It is made of an ethylene-based resin, has an apparent density of 0.10 to 0.80 g / cm 3 , a thickness of 0.5 to 5.0 mm, and an open cell ratio of 50% or less, so that it is uniform It has fine closed cells and is excellent in thermoformability.
つまり、溶融弾性の特性の指標の一つであるエチレン系樹脂のダイスェルを所定範囲に限定することによって、エチレン系樹脂の溶融時における弾性的性質を向上させ、この弾性的性質の向上によって、エチレン系樹脂の発泡工程におけるエチレン系樹脂の局所的な伸長を緩和して破泡を抑制しており、その結果、得られる熱成形用エチレン系樹脂発泡シートは、その気泡が均一にして微細で独立気泡率の高いものとなっており、表面平滑性に優れたものとなっている。 In other words, by limiting the ethylene resin die shell, which is one of the indices of melt elasticity characteristics, to a predetermined range , the elastic properties of the ethylene resin at the time of melting are improved. In the foaming process of plastic resin, local expansion of ethylene resin is eased to suppress bubble breakage. As a result, the resulting foamed ethylene resin foam sheet for thermoforming has uniform and fine bubbles. It has a high bubble rate and is excellent in surface smoothness.
更に、熱成形用エチレン系樹脂発泡シートの熱成形時においても、上述のようにエチレン系樹脂の溶融時における弾性的性質が高いことから、熱成形時に熱成形用エチレン系樹脂発泡シートに加えられる圧縮応力や延伸応力などの応力を効果的に分散、緩和することができ、本発明の熱成形用エチレン系樹脂発泡シートによれば、熱成形時に破断したり或いは破泡したりするのを防止して、外観性に優れ且つ複雑な形状を有する成形品を正確に熱成形することができる。 Furthermore, even when thermoforming an ethylene resin foam sheet for thermoforming, as described above, since the elastic properties are high when the ethylene resin is melted, it is added to the ethylene resin foam sheet for thermoforming at the time of thermoforming. Stresses such as compressive stress and stretching stress can be effectively dispersed and relaxed, and according to the ethylene-based resin foam sheet for thermoforming of the present invention, it is possible to prevent breakage or bubble breakage during thermoforming. Thus, a molded article having excellent appearance and a complicated shape can be accurately thermoformed.
そして、エチレン系樹脂が、密度が０．９４５〜０．９７０ｇ／ｃｍ 3 の高密度ポリエチレン７０〜８５重量％と、密度が０．９１５〜０．９３０ｇ／ｃｍ3 のエチレン系樹脂５〜４０重量％とからなる場合には、密度が０．９４５〜０．９７０ｇ／ｃｍ 3 の高密度ポリエチレンの有する優れた機械的強度及び耐熱性と、密度が０．９１５〜０．９３０ｇ／ｃｍ3 のエチレン系樹脂が有する押出安定性とを相乗的に発揮させることができ、熱成形用エチレン系樹脂発泡シートは、更に均一で微細な独立気泡を有していると共に外観性及び熱成形性に更に優れている。 The ethylene-based resin, a high density polyethylene 70-85% by weight of the density 0.945~0.970g / cm 3, ethylene-based resin 5 to 40 weight density 0.915~0.930g / cm 3 and if made of the%, the mechanical strength and heat resistance density and excellent with a high density polyethylene 0.945~0.970g / cm 3, density of 0.915~0.930g / cm 3 ethylene Extrusion stability of the base resin can be exhibited synergistically, and the ethylene-based resin foam sheet for thermoforming has more uniform and fine closed cells and is further excellent in appearance and thermoformability. ing.
更に、上記熱成形用エチレン系樹脂発泡シートの一面に熱可塑性樹脂フィルムを積層一体化させている場合には、熱成形用エチレン系樹脂発泡シートは、その表面平滑性及び機械的強度に更に優れている。 Furthermore, if they are stacked integrated thermoplastic resin film on one surface of the heat molding the ethylene-based resin foam sheet, an ethylene-based resin foam sheet for thermoforming it is further excellent in its surface smoothness and mechanical strength ing.
又、密度が０．９４５〜０．９７０ｇ／ｃｍ 3 の高密度ポリエチレンを７０〜８５重量％含有し且つ１９０℃におけるダイスェルが１．５５〜１．９０であるエチレン系樹脂を押出機に供給して物理型発泡剤の存在下にて溶融混練し、押出機から押出発泡させて円筒状の発泡成形体を製造し、この発泡成形体を径方向に拡径させた後に該発泡成形体をシート状に展開して熱成形用エチレン系樹脂発泡シートを製造する場合には、ダイスェルが所定値以上を有し、溶融時における弾性的性質が高いエチレン系樹脂を用いていることから、エチレン系樹脂の発泡工程におけるエチレン系樹脂の局所的な伸長を緩和して破泡を抑制することができる。 Further, ethylene resin containing 70 to 85 % by weight of high density polyethylene having a density of 0.945 to 0.970 g / cm 3 and having a die shell at 190 ° C. of 1.55 to 1.90 is supplied to the extruder. In the presence of a physical foaming agent, the mixture is melt-kneaded, extruded and foamed from an extruder to produce a cylindrical foamed molded product, and the foamed molded product is expanded in the radial direction, and then the foamed molded product is sheeted. When producing an ethylene-based resin foam sheet for thermoforming by expanding into a shape, an ethylene-based resin is used because the die shell has a predetermined value or more and has high elastic properties when melted. In this foaming step, local expansion of the ethylene-based resin can be relaxed to suppress bubble breakage.
しかも、発泡剤として物理型発泡剤を用いて、発泡成形体中に生じる気泡径が微細になり過ぎないようにして、その後の発泡成形体の拡径工程において破泡が生じないように制御しており、気泡が均一にして微細で独立気泡率が高いと共に表面平滑性及び熱成形性に優れた熱成形用エチレン系樹脂発泡シートを製造することができる。 Moreover, by using a physical foaming agent as the foaming agent, the bubble diameter generated in the foamed molded product is controlled not to become too fine, and control is performed so that bubbles do not break in the subsequent expansion process of the foamed molded product. Thus, it is possible to produce an ethylene-based resin foam sheet for thermoforming that is uniform in bubbles, is fine, has a high closed cell ratio, and is excellent in surface smoothness and thermoformability.
更に、密度が０．９４５〜０．９７０ｇ／ｃｍ 3 の高密度ポリエチレンを７０〜８５重量％含有し且つ１９０℃におけるダイスェルが１．５５〜１．９０であるエチレン系樹脂を押出機に供給して熱分解型発泡剤の存在下にて溶融混練し、押出機からシート状に押出発泡させて熱成形用エチレン系樹脂発泡シートを製造する場合には、ダイスェルが所定値以上を有し、溶融時における弾性的性質が高いエチレン系樹脂を用いていることから、エチレン系樹脂の発泡工程におけるエチレン系樹脂の局所的な伸長を緩和して破泡を抑制することができ、しかも、発泡剤として熱分解型発泡剤を用いて、押出機から押出発泡させた発泡体中の気泡を微細なものとしており、気泡が均一にして微細で独立気泡率が高いと共に表面平滑性及び熱成形性に優れた熱成形用エチレン系樹脂発泡シートを製造することができる。 Further, ethylene resin containing 70 to 85 % by weight of high density polyethylene having a density of 0.945 to 0.970 g / cm 3 and having a die shell of 1.55 to 1.90 at 190 ° C. is supplied to the extruder. In the case of producing an ethylene-based resin foam sheet for thermoforming by melt-kneading in the presence of a pyrolytic foaming agent and extruding and foaming into a sheet form from an extruder, the die shell has a predetermined value or more and is melted. Because it uses an ethylene resin with high elastic properties at the time, it can relieve local elongation of the ethylene resin in the foaming process of the ethylene resin and suppress bubble breakage. Using a pyrolytic foaming agent, the bubbles in the foam extruded and extruded from an extruder are made fine, making the bubbles uniform and fine, with a high closed cell ratio and surface smoothness and thermoformability. An excellent ethylene-based resin foam sheet for thermoforming can be produced.
（実施例１）
密度が０．９６３ｇ／ｃｍ3 の高密度ポリエチレン（日本ポリオレフィン社製 商品名「ＫＭ４９０Ｋ」、ＭＦＲ：４．０ｇ／１０分、融点：１３５℃）７５重量部と、密度が０．９２２ｇ／ｃｍ3 のエチレン系樹脂（日本ポリオレフィン社製 商品名「ＪＦ１２０Ｎ」、ＭＦＲ：０．３ｇ／１０分、融点：１１１℃）２５重量部を押出機に供給して２００℃にて溶融混練して直径が５ｍｍのストランド状に押出し水冷した後に所定長さ毎に切断してエチレン系樹脂ペレットを作製した。このエチレン系樹脂ペレットは、そのダイスェルが１．７４、密度が０．９５３ｇ／ｃｍ3 、ＭＦＲが２．１ｇ／１０分、融点：１３４℃であった。
(Example 1 )
High-density polyethylene having a density of 0.963 g / cm 3 (trade name “KM490K” manufactured by Nippon Polyolefin Co., Ltd., MFR: 4.0 g / 10 min, melting point: 135 ° C.) and 75 parts by weight, and a density of 0.922 g / cm 3 25 parts by weight of an ethylene-based resin (trade name “JF120N” manufactured by Nippon Polyolefin Co., Ltd., MFR: 0.3 g / 10 min, melting point: 111 ° C.) is supplied to an extruder and melt-kneaded at 200 ° C. to have a diameter of 5 mm. After being extruded into a strand shape and cooled with water, it was cut into predetermined lengths to produce ethylene resin pellets. This ethylene resin pellet had a die shell of 1.74, a density of 0.953 g / cm 3 , an MFR of 2.1 g / 10 min, and a melting point: 134 ° C.
エチレン系ペレット１００重量部と、熱分解型発泡剤として、重曹とクエン酸との混合物のマスターバッチ（クラリアント社製 商品名「ハイドロセロールＣＦ４０Ｅ」、重曹とクエン酸との混合物：４０重量％、エチレン系樹脂：６０重量％）０．３重量部を第一押出機に供給して溶融混練すると共に、第一押出機に物理型発泡剤としてブタンガス１．２重量部を圧入して溶融混練した後、上記第一押出機の先端に接続した第二押出機に溶融樹脂を連続的に供給して樹脂温度が１４４℃となるように調整した上で、第二押出機の先端に取り付けたサーキュラダイ（温度：１４４℃）から円筒状に押出量２５ｋｇ／時間にて押出発泡した。なお、サーキュラダイの内ダイの外径は８０ｍｍ、スリットクリアランスは０．６８ｍｍであった。そして、この円筒状発泡成形体を徐々に拡径した上で冷却マンドレルに供給して該マンドレルの外周面に円筒状発泡成形体の内周面を摺接させることによって円筒状発泡成形体を冷却した後、この円筒状発泡体をその押出方向に連続的に内外面間に亘って切断、展開して熱成形用エチレン系樹脂発泡シートを得た。なお、冷却マンドレルは、外径が２０６ｍｍで且つ長さが２００ｍｍの円筒状に形成されていた。Master batch of a mixture of sodium bicarbonate and citric acid as a thermally decomposable blowing agent (trade name “Hydrocerol CF40E” manufactured by Clariant Co., a mixture of sodium bicarbonate and citric acid: 40% by weight, (Ethylene-based resin: 60% by weight) 0.3 parts by weight was supplied to the first extruder and melt-kneaded, and 1.2 parts by weight of butane gas as a physical foaming agent was injected into the first extruder and melt-kneaded. Thereafter, the molten resin is continuously supplied to the second extruder connected to the tip of the first extruder to adjust the resin temperature to 144 ° C., and then the circular attached to the tip of the second extruder. Extrusion foaming was performed from a die (temperature: 144 ° C.) in a cylindrical shape at an extrusion rate of 25 kg / hour. The outer diameter of the inner die of the circular die was 80 mm, and the slit clearance was 0.68 mm. Then, the cylindrical foamed molded body is gradually expanded in diameter, supplied to the cooling mandrel, and the cylindrical foamed molded body is cooled by bringing the inner peripheral surface of the cylindrical foamed molded body into sliding contact with the outer peripheral surface of the mandrel. After that, this cylindrical foam was continuously cut and developed between the inner and outer surfaces in the extrusion direction to obtain an ethylene-based resin foam sheet for thermoforming. The cooling mandrel was formed in a cylindrical shape having an outer diameter of 206 mm and a length of 200 mm.
（実施例２）
密度が０．９６３ｇ／ｃｍ3 の高密度ポリエチレン（日本ポリオレフィン社製 商品名「ＫＭ４９０Ｋ」、ＭＦＲ：４．０ｇ／１０分、融点：１３５℃）７５重量部と、密度が０．９２２ｇ／ｃｍ3 のエチレン系樹脂（日本ポリオレフィン社製 商品名「ＪＫ４０１Ｎ」、ＭＦＲ：２．０ｇ／１０分、融点：１１０℃）２５重量部を押出機に供給して２００℃にて溶融混練して直径が５ｍｍのストランド状に押出し水冷した後に所定長さ毎に切断してエチレン系樹脂ペレットを作製した。このエチレン系樹脂ペレットは、そのダイスェルが１．７２、密度が０．９５２ｇ／ｃｍ3 、ＭＦＲが３．４ｇ／１０分、融点：１３３℃であった。
(Example 2 )
High-density polyethylene having a density of 0.963 g / cm 3 (trade name “KM490K” manufactured by Nippon Polyolefin Co., Ltd., MFR: 4.0 g / 10 min, melting point: 135 ° C.) and 75 parts by weight, and a density of 0.922 g / cm 3 25 parts by weight of an ethylene-based resin (trade name “JK401N” manufactured by Nippon Polyolefin Co., Ltd., MFR: 2.0 g / 10 minutes, melting point: 110 ° C.) is supplied to an extruder, melt-kneaded at 200 ° C., and a diameter of 5 mm. After being extruded into a strand shape and cooled with water, it was cut into predetermined lengths to produce ethylene resin pellets. This ethylene resin pellet had a die shell of 1.72, a density of 0.952 g / cm 3 , an MFR of 3.4 g / 10 min, and a melting point of 133 ° C.
高密度ポリエチレンの代わりに上記エチレン系樹脂ペレットを用いたこと、第二押出機にて樹脂温度１４２℃に調整した上で１４２℃に保持されたサーキュラダイから押出発泡させたこと以外は実施例１と同様にして熱成形用エチレン系樹脂発泡シートを得た。 Example 1 except that the above-mentioned ethylene-based resin pellets were used instead of high-density polyethylene, and the resin temperature was adjusted to 142 ° C. with a second extruder and extrusion foaming was performed from a circular die maintained at 142 ° C. In the same manner as above, an ethylene-based resin foam sheet for thermoforming was obtained.
（比較例１）
高密度ポリエチレンとして、密度が０．９６３ｇ／ｃｍ3 で且つ１９０℃におけるダイスェルが１．４２である高密度ポリエチレン（日本ポリオレフィン社製 商品名「ＫＭ４９０Ｋ」、ＭＦＲ：４．０ｇ／１０分、融点：１３５℃）を用いたこと以外は実施例１と同様にして熱成形用エチレン系樹脂発泡シートを得た。
(Comparative Example 1)
High density polyethylene having a density of 0.963 g / cm 3 and a die shell at 190 ° C. of 1.42 (trade name “KM490K” manufactured by Nippon Polyolefin Co., Ltd., MFR: 4.0 g / 10 min, melting point: An ethylene-based resin foam sheet for thermoforming was obtained in the same manner as in Example 1 except that 135 ° C) was used.
（比較例２）
高密度ポリエチレンとして、密度が０．９４６ｇ／ｃｍ3 で且つ１９０℃におけるダイスェルが１．４６である高密度ポリエチレン（日本ポリオレフィン社製 商品名「ＫＢ１４５Ｎ」、ＭＦＲ：０．２５ｇ／１０分、融点：１３０℃）を用いたこと、熱分解型発泡剤を０．３重量部の代わりに１．０重量部用いたこと以外は実施例１と同様にして熱成形用エチレン系樹脂発泡シートを得た。
(Comparative Example 2)
High density polyethylene having a density of 0.946 g / cm 3 and a die shell of 1.46 at 190 ° C. (trade name “KB145N” manufactured by Nippon Polyolefin Co., Ltd., MFR: 0.25 g / 10 min, melting point: 130 ° C.), and 1.0 parts by weight of the pyrolytic foaming agent was used instead of 0.3 parts by weight, and an ethylene-based resin foam sheet for thermoforming was obtained in the same manner as in Example 1. .
得られた熱成形用エチレン系樹脂発泡シートの見掛け密度、厚み、連続気泡率、中心線表面粗さ（Ｒａ）、平均気泡径、ＭＤの平均気泡径、ＴＤの平均気泡径及びＶＤの平均気泡径を上述の要領で測定し、更に、熱成形用エチレン系樹脂発泡シートを構成しているエチレン系樹脂のＭＦＲ、破断時の溶融張力及び溶融破断伸び、並びに、熱成形用エチレン系樹脂発泡シートの熱成形性及びこの熱成形用エチレン系樹脂発泡シートを成形して得られる成形品の外観性を下記の要領で測定し、その結果を表１に示した。 Apparent density, thickness, open cell ratio, centerline surface roughness (Ra), average cell diameter, MD average cell diameter, TD average cell size and VD average cell of the obtained ethylene-based resin foam sheet for thermoforming The diameter is measured as described above, and the MFR of the ethylene resin constituting the thermoforming ethylene resin foam sheet, the melt tension and melt elongation at break, and the ethylene resin foam sheet for thermoforming And the appearance of a molded product obtained by molding this thermoforming ethylene-based resin foam sheet was measured in the following manner, and the results are shown in Table 1.
（ＭＦＲ）
熱成形用エチレン系樹脂発泡シートを構成しているエチレン系樹脂のＭＦＲは、ＪＩＳ Ｋ７２１０：１９９９「プラスチック−熱可塑性プラスチックのメルトマスフローレート（ＭＦＲ）及びメルトボリュームフローレイト（ＭＶＲ）の試験方法」のＢ法に記載の方法に基づいて測定した。
(MFR)
The MFR of the ethylene-based resin constituting the ethylene-based resin foam sheet for thermoforming is JIS K7210: 1999 “Plastics—Test methods for melt mass flow rate (MFR) and melt volume flow rate (MVR) of thermoplastics”. It measured based on the method as described in B method.
具体的には、測定装置（東洋精機製作所社製 商品名「セミオートメルトインデクサー」）のシリンダーに測定試料を３〜８ｇ充填し、この測定試料を充填棒を用いて、試験温度１９０℃、試験荷重２１．１８Ｎ、予熱時間４分の条件下にてＭＦＲを測定した。なお、測定試料を３個用意し、各測定試料のＭＦＲの相加平均値をエチレン系樹脂のＭＦＲとした。 Specifically, 3 to 8 g of a measurement sample is filled in a cylinder of a measuring apparatus (trade name “Semi-auto melt indexer” manufactured by Toyo Seiki Seisakusho Co., Ltd.), and the test temperature is set to 190 ° C. using a filling rod. MFR was measured under the conditions of a load of 21.18 N and a preheating time of 4 minutes. Three measurement samples were prepared, and the arithmetic mean value of MFR of each measurement sample was MFR of ethylene resin.
（破断時の溶融張力及び溶融破断伸び）
熱成形用エチレン系樹脂発泡シートを構成しているエチレン系樹脂の破断時の溶融張力及び溶融破断伸びは、下記の要領で測定した。即ち、測定試料を１９０℃に加熱した上でキャピログラフ（東洋精機製作所社製 商品名「ＰＭＤ−Ｃ」）のシリンダー内に充填し、ピストンを降下速度１０ｍｍ／分の一定速度にて降下させてシリンダー内の測定試料をシリンダーのノズル（口径：２．０９５ｍｍ、長さ：８ｍｍ、流入角度：９０°）から紐状に垂直下方に押出した。
(Melting tension at break and melt elongation at break)
The melt tension and the melt elongation at break of the ethylene resin constituting the ethylene resin foam sheet for thermoforming were measured in the following manner. That is, the sample to be measured is heated to 190 ° C. and then filled into a capillograph (trade name “PMD-C” manufactured by Toyo Seiki Seisakusho Co., Ltd.), and the piston is lowered at a constant rate of 10 mm / min. The sample to be measured was extruded vertically downward in the form of a string from a cylinder nozzle (caliber: 2.095 mm, length: 8 mm, inflow angle: 90 °).
そして、上記シリンダーのノズルから押出した紐状物を、シリンダーのノズルの下端から垂直下方３５ｍｍの位置に配設させた張力検出のためのプーリーに通過させた後に巻取りロールに巻取り速度を約６６ｍ／ｍｉｎ2 の加速度にて上昇させつつ巻取り、紐状物が切断した時点における張力を破断時の溶融張力とし、紐状物が切断した時点における巻取り速度を溶融破断伸びとした。なお、巻取り速度１５０ｍ／ｍｉｎで紐状物が破断しない場合には、巻取り速度１５０ｍ／ｍｉｎにおける紐状物の張力を破断時の溶融張力とした。 The string-like material extruded from the nozzle of the cylinder is passed through a pulley for tension detection disposed at a position 35 mm vertically downward from the lower end of the nozzle of the cylinder, and then the winding speed is reduced to about a winding roll. Winding while increasing at an acceleration of 66 m / min 2 , the tension at the time when the string-like material was cut was taken as the melt tension at break, and the winding speed at the time when the string-like material was cut was taken as melt breaking elongation. In addition, when the string-like object did not break at the winding speed of 150 m / min, the tension of the string-like object at the winding speed of 150 m / min was set as the melt tension at the time of breaking.
（熱成形性及び外観性）
熱成形用エチレン系樹脂発泡シートから一辺３００ｍｍの平面正方形状の試験片を切り出した。この試験片をプレス成形法を用いて、底面が縦１８０ｍｍ×横１００ｍｍの平面長方形状で深さが２８ｍｍの皿状の成形品に成形した。なお、プレス成形は、１２５℃、１３０℃、１３５℃のそれぞれの温度にて１８秒間に亘って加熱することにより行った。そして、下記基準に基づいて熱成形性を目視観察にて判断し、外観性の指標として、成形品表面に、破泡や樹脂の伸び不良に起因した凹凸が形成されているか否かを目視観察により判断した。なお、表１では、凹凸がある場合を「あり」、凹凸がない場合を「なし」と表記した。
(Thermoformability and appearance)
A plane square test piece having a side of 300 mm was cut out from the ethylene-based resin foam sheet for thermoforming . This test piece was formed into a dish-shaped molded article having a bottom surface of 180 mm in length and 100 mm in width and a depth of 28 mm using a press molding method. In addition, press molding was performed by heating for 18 second at each temperature of 125 degreeC, 130 degreeC, and 135 degreeC. Then, thermoformability is judged by visual observation based on the following criteria, and visual observation is made as to whether or not the surface of the molded product has irregularities due to foam breakage or resin elongation failure, as an index of appearance. Judged by. In Table 1, the case where there is unevenness is indicated as “Yes”, and the case where there is no unevenness is indicated as “None”.
〔熱成形性〕
○・・・成形品の角部が正確に成形されており、破断も見られなかった。
×・・・成形品の角部が正確に成形されておらず、破断も見られた。
[Thermoformability]
○: The corner of the molded product was accurately molded, and no breakage was observed.
X: The corners of the molded product were not accurately molded, and breakage was observed.
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| JP4809730B2 (en) * | 2006-03-10 | 2011-11-09 | 積水化成品工業株式会社 | Styrene-modified polyolefin resin particles, expandable resin particles, pre-expanded particles, and expanded molded articles |
| JP2008075367A (en) * | 2006-09-22 | 2008-04-03 | Toppan Printing Co Ltd | Floor material and its manufacturing method |
| JP5426948B2 (en) * | 2009-07-07 | 2014-02-26 | 株式会社フジクラ | Foamed electric wire and transmission cable having the same |
| JP5700405B2 (en) * | 2010-11-19 | 2015-04-15 | 日本テトラパック株式会社 | Composition for packaging materials |
| JP5841869B2 (en) * | 2011-03-23 | 2016-01-13 | 旭化成ケミカルズ株式会社 | Substrate for molding automotive interior materials, laminated substrate for molding automotive interior materials comprising the same |
| JP6146768B2 (en) * | 2012-08-03 | 2017-06-14 | 株式会社ジェイエスピー | Method for producing polyethylene resin foam sheet |
| US9725202B2 (en) | 2013-03-14 | 2017-08-08 | Berry Plastics Corporation | Container |
| JP5808841B2 (en) * | 2014-06-05 | 2015-11-10 | 株式会社ジェイエスピー | Method for producing polyethylene resin extruded foam sheet |
| WO2016141179A1 (en) | 2015-03-04 | 2016-09-09 | Berry Plastics Corporation | Polymeric material for container |
| EP3400124B1 (en) * | 2016-01-05 | 2019-10-23 | Dow Global Technologies LLC | Thermoformed microcapillary sheeting |
| JP6551589B2 (en) * | 2018-08-10 | 2019-07-31 | 株式会社カネカ | Polypropylene-based resin foam sheet |
| JP7220067B2 (en) * | 2018-12-05 | 2023-02-09 | 積水成型工業株式会社 | LAMINATED MOLDED PRODUCT AND METHOD FOR MANUFACTURING THE SAME |
| CN110615911A (en) * | 2019-10-29 | 2019-12-27 | 恩奇(佛山)新材料科技有限公司 | Polyethylene high-rate foaming material and preparation method thereof |
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