Polymer composition and preparation method

Claim 2

A composition comprising a blend of (a) a first polymer selected from normally solid crystalline ethylene homopolymers and copolymers of ethylene containing up to about 20 mole percent of at least one comonomer selected from α-olefins having from about 3 to about 20 carbon atoms, said polymer having repeating units of the structure --CH 2 -- and a density greater than about 0.95 g/cm 3 , and (b) a second polymer selected from the group consisting of (1) non-gelled, normally solid crystalline ethylene homopolymers having repeating units of the structure --CH 2 -- and at least about two long chain Y-branches per 10,000 carbon atoms and fewer than about 10 short chain branches per 10,000 carbon atoms; (2) non-gelled, normally solid crystalline ethylene homopolymers and copolymers of ethylene containing up to about 20 mole percent of at least one comonomer selected from α-olefins having from about 3 to about 20 carbon atoms, having repeating units of the structure --CH 2 -- and a g value of less than about 0.9 and an intrinsic viscosity of less than about 3.0; (3) non-gelled, normally solid crystalline ethylene homopolymers and copolymers of ethylene containing up to about 20 mole percent of at least one comonomer selected from α-olefins having from about 3 to about 20 carbon atoms, having repeating units of the structure --CH 2 -- and comprising molecules exhibiting a numerical excess of long chain Y-branching over short chain branching; and (4) non-gelled, normally solid crystalline ethylene homopolymers and copolymers of ethylene containing up to about 20 mole percent of at least one comonomer selected from α-olefins having from about 3 to about 20 carbon atoms, having repeating units of the structure --CH 2 -- and comprising molecules having at least 2 long chain Y-branches per 10,000 carbon atoms and flow activation energy E * greater than 20 kcal/mole.

Claim 3

The composition of claim 1 in which the second ethylene polymer has more than about 5 long chain Y-branches per 10,000 carbon atoms.

Claim 4

The composition of claim 1 in which the second ethylene polymer constitutes at least about 10 weight percent of the blend.

Claim 5

The composition of claim 1 in which the second ethylene polymer comprises molecules having about 7 to about 50 long chain Y-branches per 10,000 carbon atoms.

Claim 6

The composition of claim 1 in which the first ethylene polymer is an ethylene homopolymer having a density of at least about 0.95 and fewer than about 2 long chain Y-branches per 10,000 carbon atoms.

Claim 7

The composition of claim 1 in which the second ethylene polymer is a product of a non-gelling gamma irradiation of polyethylene in the melt in vacuo, the polyethylene having a density of at least about 0.95.

Claim 8

The composition of claim 6 in which the resulting blend has from about 1 to about 7 long chain branches per 10,000 carbon atoms.

Claim 9

The composition of claim 6 in which the second ethylene polymer constitutes from about 18 to about 60 weight percent of the blend.

Claim 10

The composition of claim 6 having an average of about 2 to about 5 long chain branches per 10,000 carbon atoms and a flow activation energy of at least about 12.

Claim 11

The composition of claim 6 having a flow activation energy of at least about 20.

Claim 12

The composition of claim 6 which is a product of extrusion blending the first and second polymers.

Claim 13

The composition of claim 6 in which the weight average molecular weights of the first and second polymers are within the range of about 120,000 to about 160,000.

Claim 14

The composition of claim 6 which is a product of solution blending the first and second polymers.

Claim 15

In a polymer extrusion process in which a polymer selected from ethylene homopolymers and copolymers having a density greater than about 0.95 g/cm 3 is extruded in the melt and the extruded polymer is cooled to produce a solid polymer, a process comprising prior to or during extrusion of the polymer, exposing a portion of the polymer in the melt to radiation under non-gelling, non-oxidizing conditions, wherein the extruded product comprises a mixture of high density ethylene polymer and Y-branched ethylene polymer.

Claim 16

In a polymer extrusion process in which a polymer selected from ethylene homopolymers and copolymers having a density greater than about 0.95 g/cm 3 is extruded in the melt and the extruded polymer is cooled to produce a solid polymer, a process comprising prior to or during extrusion of the polymer, exposing a portion of the polymer in the melt to radiation under non-gelling, non-oxidizing conditions, wherein the extruded product comprises a mixture of high density ethylene polymer and Y-branched ethylene polymer.

Claim 17

The process of claim 14 in which the irradiation is carried out in vacuo.

Claim 18

The process of claim 14 in which the irradiation is carried out at a temperature in the range of about 130° C. to about 300° C.

Claim 19

The process of claim 15 in which the irradiation is carried out at a temperature of about 200° C. to about 280° C.

Claim 20

The process of claim 14 in which the irradiation is provided in the form of gamma rays in a dose of about 0.1 MRad to about 4 MRad.

Claim 21

The process of claim 18 in which the irradiation is carried out by exposing a moving polymer mass to intermittent radiation.

Claim 22

The process of claim 14 in which the heating of the polymer is carried out under conditions of temperature and time effective for increasing vinyl end group unsaturation in the polymer.

Claim 23

The method of claim 14 in which the irradiation step is performed under conditions effective for formation of long chain Y-branched molecules.

Claim 26

The method of claim 22 in which the blending is carried out by passing the first and second polymers through an extruder.

Claim 27

The method of claim 22 in which the blending is carried out by dissolving each of the first and second polymers in a common solvent and recovering the polymers as a solid from the solvent.

Claim 28

The method of claim 22 in which the first polymer has a density of at least about 0.95 g/ml and the second polymer has at least about 5 long chain Y-branches per 10,000 carbon atoms.

Claim 29

The method of claim 22 in which the second polymer is a product of the irradiation of a sample of the first polymer in the melt under non-gelling vacuum conditions.

Claim 30

The method of claim 28 in which the second polymer and the first polymer are blended by passing the first and second polymers in the melt through an extruder simultaneously to produce an extrusion product.

Claim 31

The method of claim 29 in which the extrusion product is passed in the melt to a blow molding zone and is converted to a molded article.

Claim 32

The method of claim 24 in which the activation energy of the second polymer is at least about 35 kcal/mole.

Claim 33

The method of claim 24 in which the second polymer is present in the blend of the first and second polymers in an amount of at least about 5 weight percent of the blend.

Claim 34

The method of claim 32 in which the second polymer is present in the blend in an amount of about 18 to about 60 weight percent.

Claim 35

A blow molding composition prepared by the process of blending (a) a first polymer selected from normally solid crystalline ethylene homopolymers and copolymers of ethylene containing up to about 20 mole percent of at least one comonomer selected from α-olefins having from about 3 to about 20 carbon atoms, having repeating units of the structure --CH 2 -- and a density greater than about 0.95 g/cm 3 and (b) a second polymer selected from the group consisting of (1) non-gelled, normally solid crystalline ethylene homopolymers having repeating units of the structure --CH 2 -- and at least about two long chain Y-branches per 10,000 carbon atoms and fewer than about 10 short chain branches per 10,000 carbon atoms; (2) non-gelled, normally solid crystalline ethylene homopolymers and copolymers of ethylene containing up to about 20 mole percent of at least one comonomer selected from α-olefins having from about 3 to about 20 carbon atoms, having repeating units of the structure --CH 2 -- and a g value of less than about 0.9 and an intrinsic viscosity of less than about 3.0; (3) non-gelled, normally solid crystalline ethylene homopolymers and copolymers of ethylene containing up to about 20 mole percent of at least one comonomer selected from α-olefins having from about 3 to about 20 carbon atoms, having repeating units of the structure --CH 2 -- and comprising molecules exhibiting a numerical excess of long chain Y-branching over short chain branching; and (4) non-gelled, normally solid crystalline ethylene homopolymers and copolymers of ethylene containing up to about 20 mole percent of at least one comonomer selected from α-olefins having from about 3 to about 20 carbon atoms, having repeating units of the structure --CH 2 -- and comprising molecules having at least 2 long chain Y-branches per 10,000 carbon atoms and flow activation energy E * greater than 20 kcal/mole.

Claim 36

A blow molding composition prepared by the process of blending (a) a first polymer selected from normally solid crystalline ethylene homopolymers and copolymers of ethylene containing up to about 20 mole percent of at least one comonomer selected from α-olefins having from about 3 to about 20 carbon atoms, having repeating units of the structure --CH 2 -- and a density greater than about 0.95 g/cm 3 and (b) a second polymer selected from the group consisting of (1) non-gelled, normally solid crystalline ethylene homopolymers having repeating units of the structure --CH 2 -- and at least about two long chain Y-branches per 10,000 carbon atoms and fewer than about 10 short chain branches per 10,000 carbon atoms; (2) non-gelled, normally solid crystalline ethylene homopolymers and copolymers of ethylene containing up to about 20 mole percent of at least one comonomer selected from α-olefins having from about 3 to about 20 carbon atoms, having repeating units of the structure --CH 2 -- and a g value of less than about 0.9 and an intrinsic viscosity of less than about 3.0; (3) non-gelled, normally solid crystalline ethylene homopolymers and copolymers of ethylene containing up to about 20 mole percent of at least one comonomer selected from α-olefins having from about 3 to about 20 carbon atoms, having repeating units of the structure --CH 2 -- and comprising molecules exhibiting a numerical excess of long chain Y-branching over short chain branching; and (4) non-gelled, normally solid crystalline ethylene homopolymers and copolymers of ethylene containing up to about 20 mole percent of at least one comonomer selected from α-olefins having from about 3 to about 20 carbon atoms, having repeating units of the structure --CH 2 -- and comprising molecules having at least 2 long chain Y-branches per 10,000 carbon atoms and flow activation energy E * greater than 20 kcal/mole.

Claim 37

An article prepared by molding the composition of claim 32.

Claim 38

An article prepared by blow molding the composition of claim 32.

Claim 39

A composition comprising a blend of (a) a first polymer selected from normally solid crystalline ethylene homopolymers and copolymers of ethylene containing up to about 20 mole percent of at least one comonomer selected from α-olefins having from about 3 to about 20 carbon atoms, having repeating units of the structure --CH 2 -- and a density greater than about 0.95 g/cm 3 , and (b) a second polymer selected from non-gelled, normally solid crystalline ethylene homopolymers having repeating units of the structure --CH 2 -- and at least about two long chain Y-branches per 10,000 carbon atoms and fewer than about 10 short chain branches per 10,000 carbon atoms.

Claim 40

A composition comprising a blend of (a) a first polymer selected from normally solid crystalline ethylene homopolymers and copolymers of ethylene containing up to about 20 mole percent of at least one comonomer selected from α-olefins having from about 3 to about 20 carbon atoms, having repeating units of the structure --CH 2 -- and a density greater than about 0.95 g/cm 3 , and (b) a second polymer selected from non-gelled, normally solid crystalline ethylene homopolymers having repeating units of the structure --CH 2 -- and at least about two long chain Y-branches per 10,000 carbon atoms and fewer than about 10 short chain branches per 10,000 carbon atoms.

Claim 41

A composition comprising a blend of (a) a first polymer selected from normally solid crystalline ethylene homopolymers and copolymers of ethylene containing up to about 20 mole percent of at least one comonomer selected from α-olefins having from about 3 to about 20 carbon atoms, having repeating units of the structure --CH 2 -- and a density greater than about 0.95 g/cm 3 , and (b) a second polymer selected from non-gelled, normally solid crystalline ethylene homopolymers and copolymers of ethylene containing up to about 20 mole percent of at least one comonomer selected from α-olefins having from about 3 to 20 carbon atoms, having repeating units of the structure --CH 2 -- and g value of less than about 0.9 and an intrinsic viscosity of less than about 3.0.

Claim 42

A composition comprising a blend of (a) a first polymer selected from normally solid crystalline ethylene homopolymers and copolymers of ethylene containing up to about 20 mole percent of at least one comonomer selected from α-olefins having from about 3 to about 20 carbon atoms, having repeating units of the structure --CH 2 -- and a density greater than about 0.95 g/cm 3 , and (b) a second polymer selected from non-gelled, normally solid crystalline ethylene homopolymers and copolymers of ethylene containing up to about 20 mole percent of at least one comonomer selected from α-olefins having from about 3 to 20 carbon atoms, having repeating units of the structure --CH 2 -- and g value of less than about 0.9 and an intrinsic viscosity of less than about 3.0.

Claim 43

A composition comprising a blend of (a) a first polymer selected from normally solid crystalline ethylene homopolymers and copolymers of ethylene containing up to about 20 mole percent of at least one comonomer selected from α-olefins having from about 3 to about 20 carbon atoms, having repeating units of the structure --CH 2 -- and a density greater than about 0.95 g/cm 3 , and (b) a second polymer selected from non-gelled, normally solid crystalline ethylene homopolymers and copolymers of ethylene containing up to about 20 mole percent of at least one comonomer selected from α-olefins having from about 3 to about 20 carbon atoms, having repeating units of the structure --CH 2 -- and comprising molecules exhibiting a numerical excess of long chain Y-branching over short chain branching.

Claim 44

A composition comprising a blend of (a) a first polymer selected from normally solid crystalline ethylene homopolymers and copolymers of ethylene containing up to about 20 mole percent of at least one comonomer selected from α-olefins having from about 3 to about 20 carbon atoms, having repeating units of the structure --CH 2 -- and a density greater than about 0.95 g/cm 3 , and (b) a second polymer selected from non-gelled, normally solid crystalline ethylene homopolymers and copolymers of ethylene containing up to about 20 mole percent of at least one comonomer selected from α-olefins having from about 3 to about 20 carbon atoms, having repeating units of the structure --CH 2 -- and comprising molecules exhibiting a numerical excess of long chain Y-branching over short chain branching.

Claim 45

A composition comprising a blend of (a) a first polymer selected from normally solid crystalline ethylene homopolymers and copolymers of ethylene containing up to about 20 mole percent of at least one comonomer selected from α-olefins having from about 3 to about 20 carbon atoms, having repeating units of the structure --CH 2 -- and a density greater than about 0.95 g/cm 3 , and (b) a second polymer selected from non-gelled, normally solid crystalline ethylene homopolymers and copolymers of ethylene containing up to about 20 mole percent of at least one comonomer selected from α-olefins having from about 3 to about 20 carbon atoms, having repeating units of the structure --CH 2 -- and comprising molecules having at least 2 long chain Y-branches per 10,000 carbon atoms and flow activation energy E * of greater than 20 kcal/mole.

Claim 46

A composition comprising a blend of (a) a first polymer selected from normally solid crystalline ethylene homopolymers and copolymers of ethylene containing up to about 20 mole percent of at least one comonomer selected from α-olefins having from about 3 to about 20 carbon atoms, having repeating units of the structure --CH 2 -- and a density greater than about 0.95 g/cm 3 , and (b) a second polymer selected from non-gelled, normally solid crystalline ethylene homopolymers and copolymers of ethylene containing up to about 20 mole percent of at least one comonomer selected from α-olefins having from about 3 to about 20 carbon atoms, having repeating units of the structure --CH 2 -- and comprising molecules having at least 2 long chain Y-branches per 10,000 carbon atoms and flow activation energy E * of greater than 20 kcal/mole.

Claim 47

The composition of claim 36 in which the second polymer has at least 2 long chain Y-branches per 10,000 carbon atoms.

Claim 48

The composition of claim 37 in which the second polymer has at least 2 long chain Y-branches per 10,000 carbon atoms.

Claim 49

A composition comprising a blend of (a) a first polymer selected from normally solid ethylene homopolymers and copolymers of ethylene containing up to about 20 mole percent of at least one comonomer selected from α-olefins having from about 3 to about 20 carbon atoms, said polymer having repeating units of the structure --CH 2 -- and (b) a second polymer selected from non-gelled, normally solid crystalline ethylene homopolymer and copolymers of ethylene containing up to about 20 mole percent of at least one comonomer selected from α-olefins having 3 to about 20 carbon atoms, having repeating units of the structure --CH 2 -- and a flow activation energy greater than 20 kcal/mole.

Claim 50

A composition comprising a blend of (a) a first polymer selected from normally solid ethylene homopolymers and copolymers of ethylene containing up to about 20 mole percent of at least one comonomer selected from α-olefins having from about 3 to about 20 carbon atoms, said polymer having repeating units of the structure --CH 2 -- and (b) a second polymer selected from non-gelled, normally solid crystalline ethylene homopolymer and copolymers of ethylene containing up to about 20 mole percent of at least one comonomer selected from α-olefins having 3 to about 20 carbon atoms, having repeating units of the structure --CH 2 -- and a flow activation energy greater than 20 kcal/mole.