Disclosed is an ethylenic copolymer having Mw/Mn, as measured through GPC, of from 1.5 to 4, Mw of from 3,000 to 1,000,000, and a resin density of from 0.85 and 0.95 g/cm
3
. The relationship between the half width at the half maximum [W/2] of the curve as obtained through Gaussian distribution approximation relative to the essential peak of the compositional distribution curve of the copolymer obtained through temperature rising elution fractionation analysis, and the average, n, of short-chain branches existing in the copolymer satisfies an equation, 0.704+0.147n ≦W/2≦−0.055+0.577n. Also disclosed is an ethylenic copolymer having Mw/Mn of from 1.5 to 4 and a resin density of from 0.85 and 0.95 g/cm
3
. The tear strength (TS, kgf/cm) of the copolymer satisfies equations,
TS
≧131.5−155×log[{(
B+C+D
)/
A
}+0.1],
and
0.1≦(
B+C+D
)/
A
≦1.
In these, A indicates the area of the range surrounded by the curve as obtained through the Gaussian distribution approximation, and the base line of the compositional distribution curve; B indicates the area of the range surrounded by the compositional distribution curve, the curve obtained through Gaussian distribution approximation, and the base line, the area of B being in the lower elution temperature side and being at an elution temperature higher than 32° C., while C indicates the area of the range surrounded by these three and falling in the higher elution temperature side; and D indicates the area of the range surrounded by the compositional distribution curve and the base line and falling within at an elution temperature range between 25 and 32° C. Further disclosed is an ethylenic copolymer composition comprising any of such ethylenic copolymers. The ethylenic copolymers have a narrow molecular weight distribution and a narrow branching degree distribution while having a controlled compositional distribution profile, and therefore can be formed into films having good mechanical characteristics including tear strength and impact strength and having good heat-sealing properties and high ESCR (environmental stress crack resistance).
本发明公开了一种
乙烯共聚物,通过
GPC 测量,其 Mw/Mn 为 1.5 至 4,Mw 为 3,000 至 1,000,000,
树脂密度为 0.85 至 0.95 克/厘米 3。
3
.通过高斯分布近似法得到的共聚物成分分布曲线相对于升温洗脱分馏分析得到的共聚物成分分布曲线的主峰的半最大宽度[W/2]与共聚物中存在的短链分支的平均值 n 之间的关系满足等式 0.704+0.147n≦W/2≦-0.055+0.577n。还公开了一种
乙烯共聚物,其 Mw/Mn 为 1.5 至 4,
树脂密度为 0.85 至 0.95 g/cm3
3
.该共聚物的抗撕裂强度(
TS,kgf/cm)满足以下公式、
撕裂强度
≧131.5−155×log[{(
B+C+D
)/
A
}+0.1]、
和
0.1≦(
B+C+D
)/
A
≦1。
其中,A 表示通过高斯分布近似得到的曲线和成分分布曲线基线所包围的范围的面积;B 表示成分分布曲线、通过高斯分布近似得到的曲线和基线所包围的范围的面积,B 的面积位于洗脱温度较低的一侧,且洗脱温度高于 32 摄氏度、进一步公开的是一种
乙烯共聚物组合物,包含上述任何一种
乙烯共聚物。这种
乙烯共聚物具有窄分子量分布和窄支化度分布,同时具有受控的成分分布曲线,因此可以形成具有良好机械特性(包括撕裂强度和冲击强度)的薄膜,并具有良好的热封性能和高ESCR(耐环境应力开裂性)。