Formulation containing a high density polyethylene composition and microirrigation drip tapes containing the same

Patent metadata

Field	Value
Publication number	US-11345799-B2
Application number	US-201816768294-A
Country	US
Kind code	B2
Filing date	Dec 11, 2018
Priority date	Dec 15, 2017
Publication date	May 31, 2022
Grant date	May 31, 2022

Abstract

The present disclosure provides formulation. The formulation contains a high density polyethylene composition containing (i) a high molecular weight component including an ethylene/a-olefin copolymer, the high molecular weight component having a density from 0.924 to 0.930 g/cc and a high load melt index (121) from 0.3 to 0.9 g/10 min; and (ii) a low molecular weight component including an ethylene-based polymer selected from the group consisting of an ethylene homopolymer and an ethylene/a-olefin copolymer. The high density polyethylene composition has (a) a density from 0.950 to 0.956 g/cc; (b) a high load melt index (121) from 15 to 28 g/10 min; (c) an 121/12 of at least 85; (d) a notched constant tensile load failure time at 35% yield stress of greater than 90 hours; and (e) an environmental stress crack resistance (ESCR) F0 value, according to ASTM D1693—condition B (100% IGEPAL), of greater than 2,000 hours.

First claim

We claim:

1. A formulation comprising a high density polyethylene composition, wherein the high density polyethylene composition comprises:
(i) a high molecular weight component comprising an ethylene/α-olefin copolymer, the high molecular weight component having a density from 0.924 g/cc to 0.930 g/cc and a high load melt index (I21) from 0.3 g/10 min to 0.9 g/10 min, as measured according to ASTM D1238 (190° C., 21.6 kg); and
(ii) a low molecular weight component comprising an ethylene-based polymer selected from the group consisting of an ethylene homopolymer and an ethylene/α-olefin copolymer; and
the high density polyethylene composition has:
(a) a density from 0.950 g/cc to 0.956 g/cc;
(b) a high load melt index (I21) from 15 g/10 min to 28 g/10 min;
(c) an I21/I2 of at least 85, wherein I2 is the melt index as measured according to ASTM D1238 (190° C., 2.16 kg);
(d) a notched constant tensile load failure time at 35% yield stress, as measured according to ASTM D5397, of greater than 90 hours; and
(e) an environmental stress crack resistance (ESCR) F0 value, according to ASTM D1693—condition B (100% IGEPAL), of greater than 2,000 hours.

2. The formulation of claim 1 , wherein the high density polyethylene composition has a molecular weight distribution (Mw/Mn) from 15 to 23.

3. The formulation of claim 1 comprising from 45 wt % to 60 wt % of the high molecular weight component, based on the total weight of the high density polyethylene composition.

4. The formulation of claim 1 , wherein the high density polyethylene composition has
(f) a shear thinning index (SHI) (2.7/210) from 30 to 50, as measured at 190° C.

5. The formulation of claim 1 , wherein the high density polyethylene corn position has
(g) a die swell ratio of less than 1.25.

6. The formulation of claim 1 , wherein the high density polyethylene corn position has
(h) a tensile stress at yield from 20 MPa to 30 MPa, as measured according to ASTM D638 (2 inch/min crosshead speed).

7. The formulation of claim 1 further comprising carbon black.

8. The formulation of claim 7 comprising from 0.5 wt % to 5 wt % of the carbon black.

9. The formulation of claim 1 comprising at least 90 wt % of the high density polyethylene composition.

10. A microirrigation drip tape comprising the formulation of claim 1 .

Assignees

• Dow Global Technologies Llc

Inventors

• Whited Stephanie M
• Athreya Siddharth Ram
• Kapur Mridula
• Stolarz Alexander
• Velasquez Adriana

Classifications

• C08L2205/025

  containing two or more polymers of the same hierarchy C08L, and differing only in parameters such as density, comonomer content, molecular weight, structure · CPC title

• A01G25/023

  Dispensing fittings for drip irrigation, e.g. drippers · CPC title

• C08F210/16

  Copolymers of ethene with alpha-alkenes, e.g. EP rubbers · CPC title

• A01G25/02

  Watering arrangements located above the soil which make use of perforated pipe-lines or pipe-lines with dispensing fittings, e.g. for drip irrigation · CPC title

• C08L2205/03

  containing three or more polymers in a blend · CPC title