The present invention provides a multilayered pellet having a core-shell structure, wherein the core of the core-shell structure is made of an ethylene-vinyl alcohol copolymer resin composition (A), and the shell of the core-shell structure is made of an ethylene-vinyl alcohol copolymer resin composition (B). The ethylene-vinyl alcohol copolymer resin composition (A) constituting the multilayered pellet contains any one of (i) to (iii): (i) an ethylene-vinyl alcohol copolymer (a) and a modified ethylene-vinyl alcohol copolymer (b); (ii) a modified ethylene-vinyl alcohol copolymer (b); and (iii) an ethylene-vinyl alcohol copolymer (a) and a plasticizer (d). The modified ethylene-vinyl alcohol copolymer (b) is preferably a modified ethylene-vinyl alcohol copolymer having a predetermined unit or a modified ethylene-vinyl alcohol copolymer obtained by reacting the ethylene-vinyl alcohol copolymer (a) and a monovalent epoxy compound (c) having a molecular weight of not greater than 500. Difference of the heat sealing temperature (TA) of the ethylene-vinyl alcohol copolymer resin composition (A) and the heat sealing temperature (TB) of the ethylene-vinyl alcohol copolymer composition (B) is in the range of 3 °C to 100°C.
本发明提供了一种具有芯壳结构的多层颗粒,其中芯壳结构的芯由
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乙烯醇共聚物
树脂组合物(A)制成,芯壳结构的壳由
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乙烯醇共聚物
树脂组合物(B)制成。构成多层颗粒的
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乙烯醇共聚物
树脂组合物(A)包含以下(i)至(iii)中的任意一种:(i)
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乙烯醇共聚物(a)和改性
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乙烯醇共聚物(b);(ii) 改性
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乙烯醇共聚物(b);以及(iii)
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乙烯醇共聚物(a)和
增塑剂(d)。改性
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乙烯醇共聚物(b)最好是具有预定单元的改性
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乙烯醇共聚物,或者是通过
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乙烯醇共聚物(a)和分子量不大于 500 的一价环氧化合物(c)反应得到的改性
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乙烯醇共聚物。
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树脂组合物(A)的热封温度(TA)与
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乙烯醇共聚物组合物(B)的热封温度(TB)之差在 3°C 至 100°C 之间。