 Processing aid for polymers |
| OF THE INVENTION In accordance with the present invention it has been discovered, surprisingly, ... |
|
| Non-agglomerating elastomeric organopolysiloxane particulates produced by polycondensation crosslinking |
| OF THE PREFERRED EMBODIMENTS OF THE INVENTION More particularly according to the present invention,... |
|
| Polyolefin/segmented copolymer blend and process |
| In general this invention relates to a polymer blend comprising or consisting essentially of: a) a ... |
|
| Polymers containing nylon and halogenated polymer |
| The present invention provides polymer compositions and polymer articles having optimized ... |
|
| Packaging material for photosensitive materials |
| It is an object of the invention to provide a packaging material for photosensitive materials which ... |
|
| Vinyl chloride resin composition for coating electric wires |
| I claim: 1. An electric wire coated with a vinyl chloride resin composition, the coating being ... |
|
| Modified elastomer and laminate thereof |
| What is claimed is: 1. A modified elastomer composition including modified elastomer and ... |
|
|
Polyethylene composition
| Details |
Inventors: Tajima, Yoshio; Nomiyama, Kazutosi; Shimo, Yoshiyuki; Kuroda, Nobuyuki; Matsuura, Kazuo;
Assignee: Nippon Oil Co., Ltd. (Tokyo, JP)
Primary Examiner: Seccuro; Carman J.
Assistant Examiner:
Attorney, Agent or Firm: Oblon, Fisher, Spivak, McClelland & Maier
Disclosed is polyethylene composition having excellent environmental stress cracking resistance (ESCR) and giving molded articles with good surface properties. This composition comprises a blend of two specific types of polyethylene selected with due consideration for their molecular weight distribution in addition to their molecular weights, so that it has excellent melt tension, ESCR and moldability. Accordingly, it can suitably be used in blow molding and extrusion molding to produce molded articles with no shark skin, as well as vessels of very large size. This composition is formed by blending (A) polyethylene obtained according to a two-step polymerization process using a Ziegler catalyst containing magnesium and titanium, and (B) high-molecular-weight polyethylene obtained with the aid of a chromium-containing catalyst, in a specified proportion. |
|
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The polyethylene (hereinafter referred to as component (A)) used in the present invention is polymer obtained by polymerizing ethylene, optionally together with an .
alpha.
-olefin of up to 4 carbon atoms, according to a two-step polymerization process using a Ziegler catalyst containing at least magnesium and titanium, and characterized by a density of 0.
940 to 0.
960 g/cm.
sup.
3, an intrinsic viscosity [.
eta.
] of 2.
0 to 5.
0 dl/g, preferably 2.
5 to 4.
5 dl/g, as measured in decalin at 135.
degree.
C.
, and an N value of 2.
0 to 3.
5, preferably 2.
2 to 3.
5.
If the density of component (A) is less than 0.
940 g/cm.
sup.
3, the resulting composition will show a reduction in rigidity, while if it is greater than 0.
960 g/cm.
sup.
3, the resulting composition will show a reduction in impact resistance.
If the intrinsic viscosity [.
eta.
] is less than 2.
0 dl/g, the resulting composition will have poor moldability, while if it is greater than 5.
0 dl/g, the resulting composition will have poor compatibility and low melting characteristics.
N value is a measure of the non-Newtonian viscosity of a molten polymer, but also serves as a measure of the its molecular-weight distribution (the method for the measurement of N value will be described later).
If the N value is less than 2.
0, the resulting composition will have a narrow molecular-weight distribution and hence poor moldability and compatibility, while if it is greater than 3.
5, the resulting composition will tend to undergo gelation and may have poor compatibility.
The Ziegler catalyst used in the preparation of component (A) is a catalyst containing at least magnesium and titanium.
More specifically, this Ziegler catalyst is chiefly composed of (a) a solid component formed by providing a magnesium compound selected from magnesium halides, alkylmagnesium halides, magnesium alkoxydes, magnesium oxide, magnesium hydroxide, magnesium carbonate and the like, optionally treating or reacting it with a compound selected from electron donors (such as alcohols, aldehydes, ketones, ethers, carboxylic acids, esters, thiols, acid amides, amines, nitriles, organic phosphates, organic phosphites, etc
|
|
Adhesives and Rubbers 
