Ethylene copolymer

• US 4,405,774 A
• Filed: 12/18/1981
• Issued: 09/20/1983
• Est. Priority Date: 12/23/1980
• Status: Expired due to Term

• Current Assignee: Mitsubishi Petrochemical Co., Ltd. (Mitsubishi Chemical Group Corp.)
• Original Assignee: Mitsubishi Petrochemical Co., Ltd. (Mitsubishi Chemical Group Corp.)
• Inventors: Hayashi, Shigekazu, Nakagawa, Hideaki, Shimada, Takeo, Matsuura, Mitsuyuki, Miwa, Yukimasa, Ukita, Michito
• Primary Examiner(s): Smith, Edward J.
• Application Number:
  US06/331,966
• Time in Patent Office: 641 Days
• Field of Search: 526/348.2, 526/348.3, 526/348.4, 526/348.5, 526/348.6
• US Class Current: 526/348.2
• CPC Class Codes: C08F 210/08 Butenes
• CPC Class Codes: C08F 210/14 Monomers containing five or more carbon atoms
• CPC Class Codes: C08F 210/16 Copolymers of ethene with alpha-alkenes, e.g. EP rubbers
• CPC Class Codes: C08F 2500/03 Narrow molecular weight distribution, i.e. Mw/Mn < 3
• CPC Class Codes: C08F 2500/12 Melt flow index or melt flow ratio
• CPC Class Codes: C08F 2500/26 Use as polymer for film forming
• CPC Class Codes: C08F 4/654 with magnesium or compounds thereof
• CPC Class Codes: C08F 4/6555 and magnesium or compounds thereof
• CPC Class Codes: C08F 4/6565 and magnesium or compounds thereof

Abstract

A copolymer of ethylene and a minor proportion of an α-olefin having 4 to 10 carbon atoms is characterized by having the properties

(1) a melt flow rate (MFR) of 0.1 to 100 g/10 min.;

(2) a density of 0.91 to 0.94 g/cm³ ; and

(3) a xylene absorption per unit amorphous region (Y) satisfying the formula:

Y<-0.80X+0.67

wherein X is the degree of the crystallinity of the copolymer. By satisfying the above requirements, the copolymer can give a film packaging material having excellent transparency, impact strength and opening property (anti-blocking property) in combination.

Claims

1. A copolymer of ethylene and a minor proportion of an α

-olefin having 4 to 10 carbon atoms, characterized by having in combination the properties of;

(1) a melt flow rate (MFR) of 0.1 to 100 g/10 min.;

(2) a density of 0.91 to 0.94 g/cm³ ; and

(3) a xylene absorption per unit amorphous region (Y) satisfying the following formula;

space="preserve" listing-type="equation">Y<

-0.80X+0.67

wherein X is the degree of crystallinity of the copolymer.

2. A copolymer as claimed in claim 1, wherein the xylene absorption per unit amorphous region (Y) satisfies the formula:

space="preserve" listing-type="equation">Y≦

-0.92X+0.70.

3. A copolymer as claimed in claim 1 or 2, wherein the MFR and the density are as follows:

MFR;

0.5 to 10 g/10 min.;

Density;

0.915 to 0.930.

4. A copolymer as claimed in claim 1, wherein the content of the α

-olefin having 4 to 10 carbon atoms is in the range of from 1.0 to 5.0 mole% of the total of the ethylene and the α

-olefin contents.

5. A copolymer as claimed in claim 1, wherein the α

-olefin has 6 to 8 carbon atoms.

6. A copolymer as claimed in claim 1, which has a molecular weight distribution Q value (M_W /M_N) of from 2.0 to 4.0.

7. A copolymer as claimed in claim 1, which has a single melting point as determined by the differential thermal analysis.

8. A copolymer as claimed in claim 7, wherein the relationship between the highest melting point (T_MPE, degrees in Celsius) determined by the differential thermal analysis and the density (D) is represented by the following formula:

space="preserve" listing-type="equation">700D-536<

T.sub.MPE <

50D+77.

9. A copolymer as claimed in claim 8, wherein the α

-olefin has 6 to 8 carbon atoms.

10. A copolymer as claimed in claim 9, which has a molecular weight distribution Q value (M_W /M_N) of from 2.0 to 4.0.