Injection molded caps or closures, and methods thereof

Patent metadata

Field	Value
Publication number	US-11975466-B2
Application number	US-202017603456-A
Country	US
Kind code	B2
Filing date	May 29, 2020
Priority date	Jun 11, 2019
Publication date	May 7, 2024
Grant date	May 7, 2024

Abstract

An injection molded cap or closure having a weld line, wherein the injection molded cap or closure is formed from an ethylene-based resin comprising a high molecular weight component and a low molecular weight component.

First claim

We claim:

1. An injection molded cap or closure having a weld line, wherein the injection molded cap or closure is formed from an ethylene-based resin comprising:
a high molecular weight component, wherein the high molecular weight component comprises an ethylene/alpha-olefin copolymer having a density of from 0.915 g/cc to 0.940 g/cc and a high load melt index (I21.6) of from 3.0 g/10 min to 12.0 g/10 min; and
a low molecular weight component;
wherein the ethylene-based resin comprises 50 wt. % to 60 wt. % of the high molecular weight component; and
wherein the ethylene-based resin has:
a density of from 0.945 g/cc to 0.958 g/cc;
a melt index (I2.16) of from 1.0 g/10 min to 3.0 g/10 min;
a molecular weight distribution (Mw/Mn) of from 5.0 to 8.0, where Mw is the weight average molecular weight and Mn is the number average molecular weight; and
a cross-over relaxation time of less than 80 ms.

2. The cap or closure of claim 1 , wherein the high molecular weight has a molecular weight distribution (Mw/Mn) of from 3.5 to 5.5.

3. The cap or closure of claim 1 , wherein the high molecular weight component has a density of from 0.920 g/cc to 0.939 g/cc.

4. The cap or closure of claim 1 , wherein the low molecular weight component has a calculated density of at least 0.950 g/cc as calculated according to the following equation:

1

Density
⁢

(
PE
)

=

Weight
⁢

Fraction
⁢

(
A
)

Density
⁢

(
A
)

+

Weight
⁢

Fraction
⁢

(
B
)

Density
⁢

(
B
)

where “PE” is the ethylene-based resin, “A” is the high molecular weight component and “B” is the low molecular weight component.

5. The cap or closure of claim 1 , wherein the ethylene-based resin has a melt index (I2.16) ranging from 1.2 g/10 min to 2.7 g/10 min.

6. The cap or closure of claim 1 , wherein the ethylene-based resin comprises 50 wt. % to 57 wt. % of the high molecular weight component.

7. The cap or closure of claim 1 , wherein the ethylene-based resin has a high load melt index (I21.6) ranging from 50 g/10 min to 110 g/10 min.

8. The cap or closure of claim 1 , wherein the ethylene-based resin has an Mz of greater than or equal to 450,000 g/mol.

9. The cap or closure of claim 1 , wherein the ethylene-based resin has an Mw/Mn of 5.0 to 7.5.

10. The cap or closure of claim 1 , wherein the ethylene-based resin has an Mz/Mw of 4.1 to 5.2.

11. The cap or closure of claim 1 , wherein the ethylene-based resin has a zero shear viscosity ratio of less than or equal to 1.25.

12. The cap or closure of claim 1 , wherein the ethylene-based resin has an environmental stress crack resistance (ESCR) F50, as measured according to ASTM D-1693-01, condition B at 50° C. using 10% Tergitol NP-9 or equivalent, of 30 to 200 hours.

Assignees

• Dow Global Technologies Llc

Inventors

• Lu Keran
• Lin Yijian
• Kapur Mridula
• Lan Tian
• Whited Stephanie M
• Sugden John L
• Athreya Siddharth Ram

Classifications

• B29C45/0001 Primary

  characterised by the choice of material · CPC title

• B29D99/0096

  Producing closure members for containers, e.g. closure caps or stoppers · CPC title

• B29K2023/065

  HDPE, i.e. high density polyethylene · CPC title

• B29K2023/08

  Copolymers of ethylene (B29K2023/16 takes precedence) · CPC title

• B29K2995/0063

  Density · CPC title