Composition for odor suppression

Abstract

The present disclosure provides a composition. In an embodiment, the composition includes (A) from 85 wt % to 99 wt % of an olefin-based polymer and (B) from 15 wt % to 1 wt % of an odor suppressant. The odor suppressant is a blend of (i) particles of zinc oxide, and (ii) zinc ionomer. The zinc oxide particles have a D50 particle size from 100 nm to 3000 nm, a surface area from 1 m.sup.2/g to 9 m.sup.2/g, and a porosity less than 0.020 m.sup.3/g. The composition has a methyl mercaptan odor suppression value of less than 70 at 3 days as measured in accordance with ASTM D5504-12.

Claims

1. A composition comprising: (A) from 85 wt % to 99 wt % of an olefin-based polymer; (B) from 15 wt % to 1 wt % of an odor suppressant comprising a blend of: (i) particles of zinc oxide, the particles having a D50 particle size from 100 nm to 3000 nm, a surface area from 1 m.sup.2/g to 9 m.sup.2/g, and a porosity less than 0.020 m.sup.3/g; (ii) a zinc ionomer, and the composition has a methyl mercaptan odor suppression value of less than 70 at 3 days as measured in accordance with ASTM D5504-12.

2. The composition of claim 1, wherein the olefin-based polymer is an ethylene-based polymer to the exclusion of other polymers.

3. The composition of claim 2, wherein the ethylene-based polymer is linear low density polyethylene (LLDPE).

4. The composition of claim 1 wherein composition comprises from 0.1 wt % to 9 wt % zinc.

5. The composition of claim 4 wherein the zinc is present to the exclusion of Group 5 to Group 12 metals.

6. The composition of claim 1, wherein the weight % ratio between particles of zinc oxide (B)(i) to zinc ionomer (B)(ii) is from 3:1 to 1:7 based on total weight of the odor suppressant.

7. The composition of claim 6 wherein the weight % ratio between particles of zinc oxide (B)(i) to zinc ionomer (B)(ii) is from 1:3 to 1:7 based on total weight of the odor suppressant.

8. The composition of claim 7 wherein the odor suppressant is present in an amount from 1 wt % to 10 wt % based on total weight of the composition.

9. The composition of claim 1, wherein the particles of zinc oxide (B)(i) have a D50 particle size from 100 nm to 3000 nm; a surface area from 1.0 m.sup.2/g to 5.0 m.sup.2/g; a porosity from 0.010 m.sup.3/g to 0.015 m.sup.3/g; and the composition has a methyl mercaptan odor suppression value of less than or equal to 55 at 3 days.

10. The composition of claim 9 wherein the composition comprises a continuous-phase composed of the ethylene-based polymer and a discontinuous-phase composed of domains of the zinc oxide particles (B)(i) embedded in the zinc ionomer (B)(ii).

11. The composition of claim 9 wherein the domains have an average diameter from 500 nm to 10,000 nm.

12. The composition of claim 1 wherein the zinc ionomer is a zinc salt of a polymer selected from the group of ethylene/methyl-methacrylic acid, ethylene/vinyl acrylic acid, ethylene/methacrylate, ethylene/n-butyl acrylic acid, and ethylene acrylic acid.

13. The composition of claim 1, wherein the zinc ionomer is a zinc salt of an ethylene/acrylic acid copolymer.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a scanning electron microscope (SEM) image of a prior art composition containing a polyethylene with zinc oxide particles dispersed therein.

(2) FIG. 2 is a SEM image of a composition containing an olefin-based polymer and an odor suppressant dispersed therein, in accordance with an embodiment of the present disclosure.

DETAILED DESCRIPTION

(3) The present disclosure provides a composition. In an embodiment, a composition for suppressing odors is provided and includes (A) from 85 wt % to 99 wt % of an olefin-based polymer and (B) from 15 wt % to 1 wt % of an odor suppressant. The odor suppressant is a blend composed of (Bi) particles of zinc oxide and (Bii) zinc ionomer. The zinc oxide particles (Bi) have a D50 particle size from 100 nm to 3000 nm, a surface area from 1 m.sup.2/g to 9 m.sup.2/g, and a porosity less than 0.020 m.sup.3/g. The composition has a methyl mercaptan odor suppression value less than 70 at 3 days exposure to methyl mercaptan as measured in accordance with ASTM D5504-12.

(4) A. Olefin-Based Polymer

(5) The present composition includes an olefin-based polymer. The olefin-based polymer can be a propylene-based polymer or an ethylene-based polymer. Nonlimiting examples of propylene-based polymer include propylene copolymer, propylene homopolymer, and combinations thereof. In an embodiment, the propylene-based polymer is a propylene/α-olefin copolymer. Nonlimiting examples of suitable α-olefins include C.sub.2 and C.sub.4-C.sub.20 α-olefins, or C.sub.4-C.sub.10 α-olefins, or C.sub.4-C.sub.8 α-olefins. Representative α-olefins include ethylene, 1-butene, 1-pentene, 1-hexene, 1-heptene and 1-octene.

(6) In an embodiment, the propylene/α-olefin copolymer is a propylene/ethylene copolymer containing greater than 50 wt % units derived from propylene, or from 51 wt %, or 55 wt %, or 60 wt % to 70 wt %, or 80 wt %, or 90 wt %, or 95 wt %, or 99 wt % units derived from propylene, based on the weight of the propylene/ethylene copolymer. The propylene/ethylene copolymer contains a reciprocal amount of units derived from ethylene, or from less than 50 wt %, or 49 wt %, or 45 wt %, or 40 wt % to 30 wt %, or 20 wt %, or 10 wt %, or 5 wt %, or 1 wt %, or 0 wt % units derived from ethylene, based on the weight of the propylene/ethylene copolymer.

(7) In an embodiment, the olefin-based polymer is an ethylene-based polymer. The ethylene-based polymer can be an ethylene homopolymer or an ethylene/α-olefin copolymer.

(8) In an embodiment, the ethylene-based polymer is an ethylene/α-olefin copolymer. Nonlimiting examples of suitable α-olefins include C.sub.3-C.sub.20 α-olefins, or C.sub.4-C.sub.10 α-olefins, or C.sub.4-C.sub.8 α-olefins. Representative α-olefins include propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene and 1-octene.

(9) In an embodiment, the ethylene/α-olefin copolymer is an LLDPE that is an ethylene/C.sub.4-C.sub.8 α-olefin copolymer. The LLDPE has one, some, or all of the following properties:

(10) (i) a density from 0.910 g/cc to 0.930 g/cc; and/or

(11) (ii) a Tm from 121° C. to 123° C.; and/or

(12) (iii) a melt index from 0.5 g/10 min to 1.0 g/10 min.

(13) A nonlimiting example of a suitable LLDPE is DOWLEX 2085 available from The Dow Chemical Company.

(14) B. Odor Suppressant

(15) The present composition includes an odor suppressant. The odor suppressant is a blend of zinc oxide (“ZnO”) particles (Bi) and a zinc ionomer (Bii).

(16) B(i) Zinc Oxide

(17) The odor suppressant includes particles of zinc oxide (or “ZnO”). The ZnO particles have a D50 particle size from 100 nm to 3000 nm, a surface area from 1 m.sup.2/g to less than 10 m.sup.2/g, and a porosity less than 0.020 m.sup.3/g.

(18) In an embodiment, the ZnO particles have one, some, or all of the following properties (i)-(iii) below:

(19) (i) a particle size D50 from 100 nm, or 200 nm, or 300 nm, or 400 nm to 500 nm, or 600 nm, or 700 nm, or 800 nm, or 900 nm, or 1000 nm, or 2000 nm, or 3000 nm; and/or

(20) (ii) a surface area from 1 m.sup.2/g, or 2 m.sup.2/g, or 3 m.sup.2/g, or 4 m.sup.2/g to 5 m.sup.2/g, or 6 m.sup.2/g, or 7 m.sup.2/g, or 8 m.sup.2/g, or 9 m.sup.2/g; and/or

(21) (iii) a porosity from 0.005 m.sup.3/g, or 0.006 m.sup.3/g, or 0.008 m.sup.3/g, or 0.010 m.sup.3/g to 0.012 m.sup.3/g, or 0.013 m.sup.3/g, or 0.015 m.sup.3/g, or less than 0.020 m.sup.3/g.

(22) Nonlimiting examples of suitable ZnO particles include Zochem 102, Zochem 104 from Zochem Inc., and ZnO particles available from US Research Nanoparticles.

(23) B(ii) Zinc Ionomer

(24) The odor suppressant includes a zinc ionomer. The term “zinc ionomer,” (or “ZnI/O”) as used herein, refers to a copolymer based on a zinc salt of a copolymer of ethylene and a vinyl comonomer with an acid group. Nonlimiting examples of suitable comonomer having vinyl comonomer with an acid group include methyl/methacrylic acid, vinyl acrylic acid, methacrylate, n-butyl acrylic acid, and acrylic acid.

(25) The zinc ionomer is a cross-linked polymer in which the linkages are ionic (i.e., interchain ionic bonding) as well as covalent bonds. The zinc ionomer has positively and negatively charged groups, which are not associated with each other, providing the zinc ionomer with a polar character.

(26) Nonlimiting examples of suitable zinc ionomer include zinc salt of ethylene/acrylic acid comonomer, zinc salt of ethylene/methyl-methacrylic acid copolymer, zinc salt of ethylene/vinyl acrylic acid copolymer, zinc salt of ethylene/methacrylate copolymer, zinc salt of ethylene/n-butyl acrylic acid copolymer, and any combination thereof.

(27) In an embodiment, the zinc ionomer is a zinc salt of ethylene/acrylic acid copolymer. A nonlimiting example of a suitable zinc ionomer is AMPLIFY I/O 3701 available from The Dow Chemical Company.

(28) C. Composition

(29) The present composition includes (A) from 85 wt % to 99 wt % of the olefin-based polymer and (B) from 15 wt % to 1 wt % of the odor suppressant. The odor suppressant is mixed, or otherwise blended into the olefin-based polymer matrix. The odor suppressant is a blend of (Bi) particles of zinc oxide (ZnO) and (Bii) zinc ionomer (ZnI/O). The zinc oxide particles have a D50 particle size from 100 nm to 3000 nm, a surface area from 1 m.sup.2/g to 9 m.sup.2/g, and and a porosity less than 0.020 m.sup.3/g and is hereafter referred to as Composition 1. Composition 1 has a methyl mercaptan odor suppression value less than 70 at 3 days exposure to methyl mercaptan.

(30) The odor suppressant is present in an amount from 1 wt % to 15 wt % of Composition 1 (based on total weight of Composition 1), and the ratio of ZnO to ZnI/O (hereafter “ZnO- to ZnI/O ratio”) is from 3:1 to 1:7 based on the weight of the odor suppression. The ZnO- to ZnI/O ratio can be from 3:1, or 2:1, or 1:1 to 1:2, or 1:3, or 1:4, or 1:5, or 1:6, or 1:7.

(31) In an embodiment, the present composition includes from 85 wt %, or 90 wt % to 95 wt %, or 97 wt %, or 99 wt % component (A) that is an ethylene-based polymer. The present composition includes a reciprocal amount of component (B), or from 15 wt %, or 10 wt % to 5 wt %, or 3 wt %, or 1 wt % odor suppressant wherein the ZnO- to ZnI/O ratio is from 1:3, or 1:4, or 1:5 to 1:6, or 1:7. The zinc oxide particles (Bi) have a D50 particle size from 100 nm, or 200 nm, or 300 nm, or 400 nm to 500 nm, or 600 nm, or 700 nm, or 800 nm, or 900 nm, or 1000 nm, or 2000 nm, 3000 nm, the zinc oxide particles also have a surface area from 1 m.sup.2/g, or 2 m.sup.2/g, or 3 m.sup.2/g to 4 m.sup.2/g, or 5 m.sup.2/g, or 6 m.sup.2/g, and the zinc oxide particles also have a porosity from 0.0050 m.sup.3/g, or 0.0070 m.sup.3/g, or 0.0090 m.sup.3/g to 0.010 m.sup.3/g, or 0.013 m.sup.3/g to 0.015 m.sup.3/g and is hereafter referred to as Composition 2. Composition 2 has a methyl mercaptan odor suppression value of less than or equal to 55 at 3 days of exposure to methyl mercaptan.

(32) In an embodiment, Composition 2 contains from 1000 ppm, or 5000 ppm, or 10000 ppm, or 20000 to 30000 ppm, or 40000 ppm, or 50000 ppm, or 60000 ppm, or 90000 ppm total zinc. The term “total zinc,” as used herein, is the aggregate of zinc metal from the zinc oxide (Bi) and the zinc ionomer (Bii).

(33) In an embodiment, the ethylene-based polymer (A) is present in the composition to the exclusion of any other polymer (with exception of the ZnI/O in the odor suppression). In other words, the ethylene-based polymer is the sole polymeric component (the only polymeric component) in the composition other than the zinc ionomer. In a further embodiment, the sole polymeric component is an LLDPE (other than the zinc inomer).

(34) In an embodiment, the total zinc is present in Composition 2 to the exclusion of International Union of Pure and Applied Chemistry (IUPAC) Group 5 metals to IUPAC Group 12 metals. The term “from Group 5 metals to Group 12 metals,” as used herein, includes IUPAC Group 5 metals (Chemical Abstracts Service [CAS] VB), IUPAC Group 6 metals (CAS VIB), IUPAC Group 7 metals (CAS VIIB), IUPAC Group 8 metals (CAS VIIIB), IUPAC Group 9 metals (CAS VIIIB), IUPAC Group 10 metals (CAS VIIIB), IUPAC Group 11 metals (CAS 1B), IUPAC Group 12 metals (CAS IIB). It is understood that zinc is a Group 12 metal, with the exclusion applying to cadmium and mercury. The term “total zinc is present to the exclusion of other Group 5 to Group 12 metals,” as used herein, refers to the presence of zinc and the absence of Group 5 to Group 12 metals in the composition, whereby the composition contains from 0 ppm, or from greater than 0 ppm, or 1 ppm, or 2 ppm to 3 ppm Group 5 metal to Group 12 metal.

(35) In an embodiment, Composition 2 is a heterophasic composition and includes a continuous-phase composed of the ethylene-based polymer, component (A) and a discontinuous-phase of component (B). The discontinuous phase is in the form of discrete domains. The domains are composed of the zinc oxide particles embedded in the zinc ionomer. The domains (zinc ionomer with ZnO particles embedded therein) have an average diameter from 500 nm to 1000 nm, or 3000 nm to 5,000 nm, or 7,500 nm, or 10,000 nm as measured in accordance with OM/SEM microscopy.

(36) Applicant discovered Composition 2 having an odor suppressant with ZnO- to ZnI/O ratio from 1:3 to 1:7, ZnO with (i) D50 particle size from 100 nm to 3000 nm (ii) surface area, from 1 m.sup.2/g to 6 m.sup.2/g, and (iii) porosity from 0.005 m.sup.3/g to 0.015 m.sup.3/g yields unexpected improvement in odor suppression. The domains are homogeneously dispersed in a continuous phase composed of the ethylene-based polymer.

(37) D. Applications

(38) The present composition may be used in any application wherein a polymeric material, and an olefin-based polymer in particular, is exposed to mercaptans, H.sub.2S, disulfides or amines. Nonlimiting examples of suitable applications for the present composition include trash liners, poultry diapers, ostomy bags, mattresses, mattress covers, poultry packaging, automotive interior parts, carpet fibers, and carpet backing.

(39) In an embodiment, the composition is formed into a film. The film includes the present composition, the present composition composed of (A) from 85 wt % to 99 wt % of an olefin-based polymer and (B) from 15 wt % to 1 wt % of the odor suppressant. The odor suppressant is a blend composed of (i) particles of zinc oxide and (ii) a zinc ionomer. The zinc oxide particles have a D50 particle size from 100 nm to 3000 nm, a surface area from 1 m.sup.2/g to 9 m.sup.2/g, and a porosity less than 0.020 m.sup.3/g. The composition has a methyl mercaptan odor suppression value of less than 70 at 3 days as measured in accordance with ASTM D5504-12.

(40) In an embodiment, the film is a blown film formed from Composition 2, Composition 2 having an odor suppressant value less than 70 at 3 days, the blown film having

(41) (i) a Dart impact strength from 600 g, or 700 g, or 750 g to 775 g, or 800 g, or 825 g; and/or

(42) (ii) an Elmendorf tear strength from 300 gf, or 350 gf, or 375 gf to 400 gf, or 425 gf.

(43) All other factors being equal the more ZnO present in a polymeric composition, the greater the odor suppression capability. ZnO particle surface area and gaseous odor suppression follow a direct correlation whereby the larger the surface area of the ZnO particle, the greater the odor suppression capacity. Similarly, ZnO particle porosity and gaseous odor suppression also follow a direct correlation whereby the greater the porosity of the ZnO particle, the greater the odor suppression capacity.

(44) ZnO load and ZnO particle morphology influence processability and physical properties when present in a polymer matrix. High surface area ZnO particles (i.e., ZnO particles with surface area of 10 m.sup.2/g or greater) tend to increase the viscosity of the matrix polymer in which the ZnO particles are embedded, which may degrade polymer melt processing. High surface area ZnO particles also inhibit uniform dispersion of the ZnO particles into a polymeric matrix. Moreover, large ZnO particles (ZnO particles with average diameter greater than 3 microns) added to a polymer matrix are known to degrade polymer film properties. Large ZnO particles are problematic and often act as initiation sites for cracks, tears, and crazing within a polymer matrix, degrading physical properties such as tear strength, elongation, and Dart impact.

(45) Surprisingly, the present composition (i.e., Composition 1 and/or Composition 2) exhibits the same, or better, odor suppression capability without compromising processability and without compromising film properties. Applicant discovered the ZnI/O works synergistically with the ZnO to improve odor suppression with less total zinc (and less ZnO) compared to ZnO-polymer matrix systems containing more ZnO. ZnI/O alone has little, or no, odor suppression capability. The ability of ZnI/O to synergistically improve odor suppression when combined with ZnO particles with D50 100-3000 nm, surface area of 1-9 m.sup.2/g and porosity less than 0.02 m.sup.3/g is unexpected.

(46) By way of example, and not limitation, some embodiments of the present disclosure will now be described in detail in the following Examples.

EXAMPLES

(47) Materials used in the examples are provided in Table 1 below.

(48) TABLE-US-00001 TABLE 1 Material/Description Properties Source DOWLEX ™ 2085G LLDPE, ethylene/octene copolymer; density = 0.92 g/cc; MI The Dow (LLDPE) 0.85 g/10 min; Tm = 121.6° C. Chemical Company AMPLIFY IO ™ 3701 Metal salt of zinc ion and ethylene/acrylic acid copolymer; The Dow (ZnI/O) density = 0.940 g/cc; Tm = 95° C.; MI = 5.2 g/10 min Chemical Company Agility 1021 LDPE; density = 0.920 g/cc; Tm = 108.1° C.; MI = 1.85 g/10 min The Dow Chemical Company ZNO 800HSA ZnO D50 particle size 3000 nm; density = 5.61 g/cc; Zinc Oxide, LLC Zinc Oxide (ZnO-1) Porosity 0.0131 g/m.sup.3, surface area 4.46 m.sup.2/g powder Zinc Oxide ZnO ZnO D50 particle size 500 nm; density = 5.61 g/cc; 500 nm (US MicroPowder, ZnO, Porosity 0.008 m.sup.3/g, surface area 3.36 m.sup.2/g Research 99.9+% Nanomaterials) Zinc Oxide (ZnO-2) powder Zoco102 ZnO D50 particle size 200 nm; density = 5.61 g/cc; Zochem inc. Zinc Oxide (ZnO-3) Porosity 0.012 m.sup.3/g, surface area 4.4 m.sup.2/g powder Ampacet 110069 70 wt % TiO.sub.2 Ampacet White PE MB in Carrier Resin LLDPE (MI 2.3, d-0.917 g/cc) Corporation Titanium dioxide Masterbatch Specific gravity: 2.03 (TiO.sub.2) Masterbatch

(49) 1. Films

(50) The compositions of CS1-CS8 and IE1-IE8 are formed into a blown film by compounding the LLDPE, the ZnO (when present), the ZnI/O (when present), and the TiO.sub.2 (when present) in a 30 mm co-rotating, intermeshing Coperion Werner-Pfleiderer ZSK-30 (ZSK-30) twin screw extruder. The extruder is operated at 40 Ibs per hour under a screw rotation speed of 250 rpm. Die pressure is maintained between 450 to 500 psi. Melt temperature is maintained near 240° C. Nitrogen purging is applied at the feed throat. A standard water bath is used for cooling and a strand cut pelletizer is employed to product the pellets. Pellets were stored in ambient conditions prior to use.

(51) The blown film is a single layer film.

(52) TABLE-US-00002 TABLE 2 Blown film line process parameters Films Films without containing Parameter Units TiO.sub.2 MB TiO.sub.2 MB Takeoff m/min 15 15 Layflat cm 23.5 23.5 Frostline cm 14 14 B.U.R ratio 2.5 2.5 Die gap mm 2.0 2.0 Melt temperature - Ext. A ° C. 218 218 Melt temperature - Ext. B ° C. 226 226 Melt temperature - Ext. C ° C. 215 215 RPM - Ext. A rpm 51 51 RPM - Ext. B rpm 50 50 RPM - Ext. C rpm 32 32 Total Output kg/hr 8.8 8.8 Film Total Thickness mm 0.023 0.056

(53) In Table 3 below, Dart Impact and tear strength values are for films with 0.023 mm thickness. Films with TiO.sub.2 MB have 0.056 mm thickness, with exception to the CS7 film having a thickness of 0.023 mm.

(54) 2. Odor Suppression

(55) Odor suppression values are measured over 192 hours (8 days) in accordance with ASTM D 5504-10 as described above in the odor suppression test method.

(56) Film strips with a mass of 1 g (1 cm×30 cm and thickness in Table 2) of control samples (CS) CS1-CS8 and inventive examples (IE) IE1-IE8 are placed in Tedlar® bags filled with methyl mercaptan and helium gas carrier as described in the odor suppression test method, disclosed above.

(57) Comparative samples (CS), CS1-CS8 are prepared. CS1 is a control sample with DOWLEX 2085 and CS2 is a control sample 93 wt % LLDPE and 7 wt % TiO.sub.2 masterbatch.

(58) CS3 and CS4 are blends of ZnO and LLDPE (control) with varying amount of ZnO in the blend.

(59) CS5, CS6, CS7 are blends of zinc ionomer and LLDPE (control) with varying amount of zinc ionomer in the blend.

(60) CS8 is a blend of ZnO, TiO.sub.2 and LLDPE (control).

(61) IE1-IE8 are inventive examples of the present composition composed of LLDPE and odor suppressant composed of ZnO and ZnI/O.

(62) The odor suppression values (OSV) for CS1-CS8 and IE1-IE8 are provided in Table 3 below.

(63) TABLE-US-00003 TABLE 3 Methyl Mercaptan Odor Suppression Values and Blown Film Properties Tear Avg Dart Sample Composition Day 1 Day 2 Day 3 Day 4 Day 5 Day 8 (gf) (g) CS 1 7% wt % TiO.sub.2 MB 94 77 94 73 80 89 308 588 (control) 93 wt % LLDPE CS 2 100% LLDPE 2085 100 100 100 100 100 100 337 600 (control) CS3 5 wt % ZnO-2 (500 nm) 78 89 81 70 66 68 341 624 95 wt % LLDPE CS4 5 wt % ZnO-1 (3000 nm) 82 99 87 66 70 59 403 588 95 wt % LLDPE CS5 10 wt % Zn-I/O 116 105 114 90 92 117 263 653 90 wt % LLDPE CS6 5 wt % Zn-I/O 104 102 105 81 88 93 260 683 95 wt % LLDPE CS7 5 wt % TiO.sub.2 MB 102 91 92 83 77 89 223 653 5 wt % Zn- I/O 90 wt % LLDPE IE1 5 wt % ZnO-2 (500 nm) 37 54 56 47 47 52 337 810 5 wt % Zn-I/O 90 wt % LLDPE IE2 5 wt % ZnO-1 (3000 nm) 72 61 67 n/t n/t n/t 420 773 5 wt % AMPLIFY I/O 3701 90 wt % LLDPE CS8 5 wt % ZnO-3 (200 nm) 93 n/t 93 n/t n/t n/t 5 wt % LDPE 7 wt % TiO.sub.2 MB IE3 5 wt % ZnO-1 (3000 nm) 76 n/t 37 n/t n/t n/t 5 wt % AMPLIFY IO 7 wt % TiO2 MB IE4 5 wt % ZnO-2 (200 nm) 68 n/t 28 n/t n/t n/t 5 wt % AMPLIFY IO 7 wt % TiO.sub.2 MB IE5 1.25 wt % ZnO-3 (200 nm) 77 n/t 66 n/t n/t n/t 1.25 wt % AMPLIFY IO 7% wt % TiO.sub.2 MB IE6 2.5 wt % ZnO-3 (200 nm) 74 n/t 54 n/t n/t n/t 2.5 wt % AMPLIFY IO 7% wt % TiO.sub.2 MB IE7 3.75 wt % ZnO-3 (200 nm) 95 n/t 65 n/t n/t n/t 1.25 wt % AMPLIFY IO 7% wt % TiO.sub.2 MB IE8 1.25 wt % ZnO-3 (200 nm) 73 n/t 55 n/t n/t n/t 3.75 wt % AMPLIFY IO 7 wt % TiO.sub.2 MB *TiO.sub.2 MB—titanium dioxide masterbatch 70 wt % TiO.sub.2 powder in 30 wt % LLDPE carrier, added for white color n/t—not tested

(64) In Table 3, CS3-CS4 (ZnO only, at 5 wt %) demonstrate that ZnO only at small load (5 wt %) exhibits only a small degree of odor suppression at 3 days (OSV 81, 87 respectively).

(65) CS5-CS6 show ZnI/O only has no ability to suppress odor (114, 105 respective OSV at 3 days).

(66) CS7 shows that with ZnI/O blended with TiO.sub.2 has only a small odor suppression capability (OSV 92 at 3 days).

(67) IE1-IE8 each show significant odor suppression capability (IE1, IE2 OSV 56, 67 respectively at 3 days). For example, the ability of IE1 and IE2 to provide greater odor suppression (respective OSV: 56, 67) than CS4 (OSV: 87) is unexpected. Bounded by no particular theory, the ZnO and ZnI/O work synergistically to improve the odor suppression ability of ZnO. Further unexpected is the discovery that ZnI/O, which alone, is an ineffective odor suppressant, works synergistically with ZnO to improve odor suppression. Applicant discovered that odor suppression improves by blending ZnO with ZnI/O as opposed to increasing only the amount of ZnO in the absence of the zinc ionomer.

(68) FIG. 1 is an SEM image of CS3 (5 wt % ZnO, D50=300 nm) blended in 95 wt % LLDPE (DOWLEX 2085G). FIG. 1 shows the ZnO particles dispersed in the LLDPE matrix phase. FIG. 2 is an SEM image of IE1 (5 wt % ZnO/5 wt % ZnI/O blended in 90 wt % LLDPE).

(69) The SEM image of FIG. 2 shows the ZnI/O is a separate phase from the bulk LLDPE, and that the ZnO particles are encapsulated in the ZnI/O phase to form domains of ZnO embedded in the ZnI/O. Bounded by no particular theory, it is believed the formation of the ZnI/O—ZnO domains contributes to accelerated diffusion of odor molecules. The ZnI/O is more permeable to polar gasses (i.e., sulfur-based gasses, such as methyl mercaptan). The permeability of the ZnI/O facilitates the interaction of the odorous gas with the ZnO, contributing to the suppression of odor.

(70) The SEM image of FIG. 2 shows that the ZnI/O surrounds, and encapsulates the ZnO particles. The ZnI/O prevents cavitation at the polymer-particle interface and prevents the rupture of the overall polymer. The ZnI/O—ZnO domains do not create initiation sites.

(71) In Table 3, films CS1 through CS8 each exhibit a Dart impact strength less than 700 g whereas films IE1 and IE2 each exhibit Dart impact strength greater than 700 g and greater than 750 g (respective Dart impact values 810 g, 773 g).

(72) Table 3 shows that the physical properties of Dart impact strength, for IE1 and IE2 are either maintained or improved when the present odor suppressant (ZnO and ZnI/O) is used compared to film containing ZnO alone. Indeed, IE1 and IE2 show improvement for all film properties (Dart impact, tear) compared to the unfilled film sample of control film CS1.

(73) Applicant surprisingly discovered that the present odor suppressant (ZnO—ZnI/O) enables effective odor suppression using less total zinc utilizing ZnO particles with D50 100-3000 nm, surface area 1 m.sup.2/g-9 m.sup.2/g, and porosity less than 0.020 m.sup.3/g while simultaneously yielding blown film with improved Dart impact strength (i.e., Dart impact strength of 600 g and greater or 700 g and greater). The ability to improve odor suppression with less zinc by way of the present composition and odor suppressant while maintaining and improving film properties is unexpected.

(74) It is specifically intended that the present disclosure not be limited to the embodiments and illustrations contained herein, but include modified forms of those embodiments including portions of the embodiments and combinations of elements of different embodiments as come within the scope of the following claims.