High melt strength polypropylene with high stiffness and clarity

Patent metadata

Field	Value
Publication number	US-11549006-B2
Application number	US-201816613468-A
Country	US
Kind code	B2
Filing date	Apr 27, 2018
Priority date	May 30, 2017
Publication date	Jan 10, 2023
Grant date	Jan 10, 2023

Abstract

A polypropylene comprising within a range from 0.1 wt % to 4 wt % ethylene and/or C4 to C12 α-olefin derived units, one or more clarifiers, or both; wherein the polypropylene has a flexural modulus of at least 200 kpsi (0.05 in/min ASTM D790(A)) and an Mz/Mw of at least 4. The polypropylenes may be made by combining propylene and a comonomer with a Ziegler-Natta catalyst and at least two external electron donors, wherein the concentration of the electron donors is within a range from 1 to 100 ppm. The concentration of electron donors may be decreased to control the haze level of the polypropylene, and/or the level of comonomer derived units may be controlled to reduce the haze level of the polypropylene.

First claim

The invention claimed is:

1. A polypropylene that is reactor grade and has
a flexural modulus of at least 200 kpsi (1380 MPa) (0.05 in/min ASTM D790(A)),
an Mz/Mw of at least 4,
an Mw/Mn of at least 8,
a Mn ranging from 20 kg/mole to 80 kg/mole, a Mw ranging from 300 kg/mole to 800 kg/mole, and a Mz ranging from 1000 kg/mole to 3500 kg/mole;
wherein the polypropylene comprises:

(i) within a range from 0.1 wt % to 4 wt % ethylene derived units,
(ii) one or more clarifiers, or
(iii) both (i) and (ii).

2. The polypropylene of claim 1 , wherein the polypropylene has a melt flow rate (MFR, 230° C./2.16 kg) within a range from 0.5 g/10 min to 20 g/10 min.

3. The polypropylene of claim 1 , wherein the one or more clarifiers are present within a range from 50 ppm to 5000 ppm.

4. The polypropylene of claim 1 , wherein the polypropylene has an Mz+1 value of at least 4,800 kg/mole.

5. The polypropylene of claim 1 , wherein the polypropylene has a melting point temperature (T m ) of at least 154° C.

6. The polypropylene of claim 1 , wherein the polypropylene has a crystallization temperature (T c ) of at least 110° C.

7. The polypropylene of claim 1 , wherein the polypropylene has a clarity of at least 80%.

8. The polypropylene of claim 1 , wherein the polypropylene has a haze of less than 60%.

9. The polypropylene of claim 1 , wherein the polypropylene is made by combining propylene and optionally a comonomer with a Ziegler-Natta catalyst and at least two external electron donors, wherein a concentration of the at least two external electron donors is within a range from 1 to 100 ppm.

10. The polypropylene of claim 9 , wherein the concentration of the at least two external electron donors is decreased to reduce a haze of the polypropylene.

11. The polypropylene of claim 9 , wherein a level of the comonomer is increased to reduce a haze of the polypropylene.

12. The polypropylene of claim 9 , wherein hydrogen is combined with the propylene and the optional comonomer, and a level of the hydrogen is kept constant while the propylene and the optional comonomer are combined with the Ziegler-Natta catalyst.

13. The polypropylene of claim 1 , wherein the polypropylene is combined with an organic peroxide in a melt extrusion process to produce a branched polypropylene.

14. The polypropylene of claim 1 , further comprising from 5 to 50 wt % of a low molecular weight polyolefin.

15. The polypropylene of claim 1 , further comprising a foaming agent.

16. A thermoformed article comprising the polypropylene of claim 1 .

17. A polypropylene that is reactor grade and has
a MFR (230° C./2.16 kg) within a range from 0.5 g/10 min to 20 g/10 min,
an Mz/Mw of at least 4,
an Mw/Mn of 8 to 18,
a Mn ranging from 20 kg/mole to 80 kg/mole, a Mw ranging from 300 kg/mole to 800 kg/mole, and a Mz ranging from 1000 kg/mole to 3500 kg/mole;
wherein the polypropylene comprises:

(i) within a range from 0.1 wt % to 4 wt % ethylene derived units,
(ii) one or more clarifiers, or
(iii) both (i) and (ii).

18. The polypropylene of claim 17 , wherein the polypropylene has a melt strength (190° C.) of at least 5 cN.

19. The polypropylene of claim 17 , wherein the polypropylene has a haze of less than 60%.

20. The polypropylene of claim 17 , wherein the polypropylene is made by combining propylene and a comonomer with a Ziegler-Natta catalyst and at least two external electron donors, wherein a concentration of the at least two external electron donors is within a range from 1 to 100 ppm.

21. The polypropylene of claim 20 , wherein the concentration of the at least two external electron donors is decreased to reduce a haze of the polypropylene.

22. The polypropylene of claim 20 , wherein a level of the comonomer is increased to reduce a haze of the polypropylene.

23. The polypropylene of claim 17 , further comprising a foaming agent.

24. A thermoformed article comprising the polypropylene of claim 17 .

Assignees

• Exxonmobil Chemical Patents Inc

Inventors

• Spofford Caitlin A
• Pehlert George J
• Poloso Anthony
• Barry Adrian G
• Donahue John M

Classifications

• C08L2201/10

  Transparent films; Clear coatings; Transparent materials · CPC title

• C08J2323/10

  Homopolymers or copolymers of propene · CPC title

• C08F10/06 Primary

  Propene · CPC title

• B29C48/0012

  combined with shaping by internal pressure generated in the material, e.g. foaming · CPC title

• B29K2023/12

  PP, i.e. polypropylene · CPC title