Propylene/ethylene copolymer film for heat seal
The present disclosure provides compositions, films and articles containing a random propylene/ethylene copolymer and a substituted phenylene aromatic diester. Polymerization with an improved catalyst system increases the amount of ethylene incorporated into the random propylene/ethylene copolymer backbone which results in improved thermal properties, improved optical properties, and improved heat seal properties.
1. A film comprising:
a catalytically polymerized random propylene/ethylene copolymer the catalyst comprising a substituted 1,2-phenylene aromatic diester internal electron donor having the structure (II)
wherein R 1 -R 14 are the same or different and each of R 1 -R 14 is selected from the group consisting of hydrogen, substituted hydrocarbyl group having 1 to 20 carbon atoms, unsubstituted hydrocarbyl group having 1 to 20 carbon atoms, alkoxy group having 1 to 20 carbon atoms, a heteroatom, and combinations thereof, wherein at least one of R 1 -R 14 is not hydrogen;
the random propylene/ethylene copolymer having:
(A) an ethylene incorporation index from greater than 0.65 to 0.85; and
(B) a xylene solubles content and total ethylene content according to the following equation
wt
%
xylene
solubles
-
wt
%
total
ethylene
wt
%
total
ethylene
<0.8
;
and
(C) a Koenig B-value from 0.90 to 1.0; and
wherein the random propylene/ethylene copolymer has an ethylene ratio from greater than 2.0 up to 4.0, wherein the ethylene ratio is defined as follows:
ethylene ratio=[ethylene present in XI (wt %)]/[ethylene present in XS (wt %)];
wherein XI is the xylene insoluble portion of said copolymer and XS is the xylene soluble portion of said copolymer.
2. The film of claim 1 wherein the substituted phenylene aromatic diester is 3-methyl-5-tert-butyl-1,2-phenylene dibenzoate.
3. An article comprising:
a heat seal comprising a first seal portion in contact with a second seal portion, the first seal portion and the second seal portion each being a component of a layer,
wherein the layer comprises a catalytically polymerized random propylene/ethylene copolymer comprising a substituted 1,2-phenylene aromatic diester internal electron donor having the structure (II)
wherein R 1 -R 14 are the same or different and each of R 1 -R 14 is selected from the group consisting of hydrogen, substituted hydrocarbyl group having 1 to 20 carbon atoms, unsubstituted hydrocarbyl group having 1 to 20 carbon atoms, alkoxy group having 1 to 20 carbon atoms, a heteroatom, and combinations thereof, wherein at least one of R 1 -R 14 is not hydrogen;
the random propylene/ethylene copolymer having:
(A) an ethylene incorporation index from greater than 0.65 to 0.85; and
(B) a xylene solubles content and total ethylene content according to the following equation
wt
%
xylene
solubles
-
wt
%
total
ethylene
wt
%
total
ethylene
<0.8
;
(C) a Koenig B-value from 0.90 to 1.0; and
wherein the random propylene/ethylene copolymer has an ethylene ratio from greater than 2.0 up to 4.0, wherein the ethylene ratio is defined as follows:
ethylene ratio=[ethylene present in XI (wt %)]/[ethylene present in XS (wt %)];
wherein XI is the xylene insoluble portion of said copolymer and XS is the xylene soluble portion of said copolymer.
4. The article of claim 3 wherein each of the first seal portion and the second seal portion is a component of a single film.
5. The article of claim 3 wherein the first seal portion is a component of a first film and the second seal portion is a component of a second film.
6. The article of claim 3 wherein the layer is a biaxially oriented film.
7. The article of claim 3 wherein the layer is a seal layer of a multilayer film.
8. A container comprising:
a film comprising a catalytically polymerized random propylene/ethylene copolymer, the catalyst comprising a substituted 1,2-phenylene aromatic diester internal electron donor having the structure (II);
wherein R 1 -R 14 are the same or different and each of R 1 -R 14 is selected from the group consisting of hydrogen, substituted hydrocarbyl group having 1 to 20 carbon atoms, unsubstituted hydrocarbyl group having 1 to 20 carbon atoms, alkoxy group having 1 to 20 carbon atoms, a heteroatom, and combinations thereof, wherein at least one of R 1 -R 14 is not hydrogen;
the random propylene/ethylene copolymer having:
(A) an ethylene incorporation index from greater than 0.65 to 0.85; and
(B) a xylene solubles content and total ethylene content according to the following equation
wt
%
xylene
solubles
-
wt
%
total
ethylene
wt
%
total
ethylene
<0.8
;
(C) a Koenig B-value from 0.90 to 1.0;
wherein the random propylene/ethylene copolymer has an ethylene ratio from greater than 2.0 up to 4.0, wherein the ethylene ratio is defined as follows:
ethylene ratio=[ethylene present in XI (wt %)]/[ethylene present in XS (wt %)]; and
wherein XI is the xylene insoluble portion of said copolymer and XS is the xylene soluble portion of said copolymer and
a heat seal sealing a first film portion to a second film portion and defining a container interior.
9. The container of claim 8 wherein the first film portion and the second film portion each are a component of a single film.
10. The container of claim 8 where the first film portion is a component of a first film and the second film portion is a component of a second film.
11. The container of claim 8 comprising a comestible located in the container interior.