Amorphpus propylene-ethylene copolymers
Amorphous propylene-ethylene copolymers are described herein that can include high amounts of ethylene and exhibit desirable softening points and needle penetrations. The desirable combinations of softening points and needle penetrations in these propylene-ethylene copolymers allow them to have a broad operating window. Due their broad operating window, the propylene-ethylene copolymers can be utilized in a wide array of applications and products, including hot melt adhesives.
1. An adhesive comprising 5 to 95 weight percent of a copolymer that comprises propylene and ethylene, said copolymer exhibiting at least one of the following sets of characteristics:
(a) wherein said copolymer comprises:
at least 10 weight percent of ethylene,
a softening point in the range of 100 to 145° C.,
a needle penetration of less than 75 dmm,
a crystallinity of less than 20 percent as measured using DSC according to ASTM E 794-85, and
a Brookfield viscosity at 190° C. of less than 30,000 cps as measured according to ASTM D3236;
(b) wherein said copolymer comprises:
at least 10 weight percent of ethylene,
a softening point in the range of 85 to 145° C.,
a needle penetration of less than 75 dmm, and
a crystallinity of less than 10 percent as measured using DSC according to ASTM E 794-85; or
(c) wherein said copolymer comprises:
at least 10 weight percent of ethylene,
a softening point in the range of 119 to 145° C.,
a needle penetration of less than 75 dmm, and
a Brookfield viscosity at 190° C. of less than 30,000 cps as measured according to ASTM D3236.
2. The adhesive of claim 1 , wherein said copolymer comprises the characteristics of said set (a).
3. The adhesive of claim 1 , wherein said copolymer comprises the characteristics of said set (b).
4. The adhesive of claim 1 , wherein said copolymer comprises the characteristics of said set (c).
5. The adhesive of claim 1 , wherein said copolymer comprises the characteristics of said set (a), said set (b), and said set (c).
6. The adhesive of claim 1 , wherein said copolymer comprises 40 to 85 weight percent of propylene.
7. The adhesive of claim 1 , wherein said adhesive comprises 10 to 90 weight percent of at least one polymer that is different from said copolymer.
8. The adhesive of claim 1 , wherein said copolymer comprises in the range of 10 to 35 weight percent of ethylene.
9. The adhesive of claim 1 , wherein said copolymer comprises in the range of 1 to 20 weight percent of at least one C 4 -C 10 alpha-olefin.
10. A copolymer comprising propylene and ethylene, said copolymer exhibiting at least one of the following sets of characteristics:
(a) wherein said copolymer comprises:
at least 10 weight percent of ethylene,
a softening point in the range of 100 to 137° C.,
a needle penetration of less than 29 dmm,
a crystallinity of less than 20 percent as measured using DSC according to ASTM E 794-85, and
a Brookfield viscosity at 190° C. of less than 30,000 cps as measured according to ASTM D3236;
(b) wherein said copolymer comprises:
at least 10 weight percent of ethylene,
a softening point in the range of 85 to 128° C.,
a needle penetration of less than 75 dmm, and
a crystallinity of less than 10 percent as measured using DSC according to ASTM E 794-85; or
(c) wherein said copolymer comprises:
at least 10 weight percent of ethylene,
a softening point in the range of 119 to 137° C.,
a needle penetration of less than 29 dmm, and
a Brookfield viscosity at 190° C. of less than 30,000 cps as measured according to ASTM D3236.
11. The copolymer of claim 10 , wherein said copolymer comprises the characteristics of said set (a).
12. The copolymer of claim 10 , wherein said copolymer comprises the characteristics of said set (b).
13. The copolymer of claim 10 , wherein said copolymer comprises the characteristics of said set (c).
14. The copolymer of claim 10 , wherein said copolymer comprises the characteristics of said set (a), said set (b), and said set (c).
15. The copolymer of claim 10 , wherein said copolymer comprises 40 to 85 weight percent of propylene.
16. The copolymer of claim 10 , wherein said copolymer comprises in the range of 10 to 35 weight percent of ethylene.
17. The copolymer of claim 10 , wherein said copolymer comprises in the range of 1 to 20 weight percent of at least one C 4 -C 10 alpha-olefin.
18. The copolymer of claim 10 , wherein said copolymer comprises a needle penetration of less than 29 dmm and a softening point of less than 128° C.
19. An adhesive comprising the copolymer of claim 10 , wherein said adhesive comprises 5 to 95 weight percent of said copolymer.
20. The adhesive of claim 19 , wherein said adhesive comprises 10 to 90 weight percent of at least one polymer that is different from said copolymer.