阅读说明：本技术 用于消费后树脂的气味抑制组合物 (Odor inhibiting compositions for post-consumer resins ) 是由 C·R·麦卡尔平 A·L·克拉索夫斯基 孙科夫 S·T·麦特斯 J·M·马丁 S·R·阿瑟 于 2020-02-18 设计创作，主要内容包括：本公开提供一种组合物。在一个实施方案中,该组合物包含聚合物组分和气味抑制剂。聚合物组分包含(i)消费后树脂和(ii)任选的基于烯烃的聚合物。该组合物还包含0.15重量％至15重量％的气味抑制剂。气味抑制剂包含(i)0.05重量％至2重量％的带隙大于5.0电子伏特(eV)的金属氧化物；(ii)0.1重量％至13重量％的酸共聚物。金属氧化物与酸共聚物的比率为1∶20至1∶1。重量百分比基于组合物的总重量。(The present disclosure provides a composition. In one embodiment, the composition comprises a polymer component and an odor inhibitor. The polymer component comprises (i) a post-consumer resin and (ii) optionally an olefin-based polymer. The composition further comprises 0.15 wt% to 15 wt% of an odor inhibitor. The odor inhibitor comprises (i)0.05 to 2 wt% of a metal oxide having a band gap greater than 5.0 electron volts (eV); (ii)0.1 to 13% by weight of an acid copolymer. The ratio of metal oxide to acid copolymer is from 1: 20 to 1: 1. The weight percentages are based on the total weight of the composition.)

1. A composition, comprising:

a polymer component comprising (i) a post-consumer resin (PCR) and (ii) optionally an olefin-based polymer;

0.15 to 15 wt% of an odor inhibitor comprising based on the total weight of the composition

(i)0.05 to 2 weight percent, based on the total weight of the composition, of a metal oxide having a band gap greater than 5.0 electron volts (eV); and

(ii)0.1 to 13 weight percent of an acid copolymer based on the total weight of the composition; and

the ratio of the metal oxide to the acid copolymer is from 1: 20 to 1: 1.

2. The composition of claim 1, wherein the composition exhibits at least a 20% reduction in volatile heterocarbonyl species as measured by standardized gas chromatography compared to the polymer component without the odor inhibitor.

3. The composition of any of claims 1-2, wherein the polymer component comprises 100 wt% of a post-consumer resin, based on the total weight of the polymer component.

4. The composition of any one of claims 1-2, wherein the polymer component comprises 5 to 95 weight percent PCR and 95 to 5 weight percent of the olefin-based polymer.

5. The composition of any of claims 1-4, wherein the olefin-based composition is selected from the group consisting of ethylene-based polymers, propylene-based polymers, and combinations thereof.

6. The composition of any one of claims 1-5, wherein the metal oxide is selected from the group consisting of calcium oxide and magnesium oxide.

7. The composition of any one of claims 1-6, wherein the acid polymer is selected from the group consisting of ethylene ethyl acrylate copolymers, ethylene butyl acrylate copolymers, ethylene acrylic acid copolymers, ethylene/(meth) acrylic acid copolymers, and combinations thereof.

8. The composition of any of claims 1-7, wherein the odor inhibitor is a pre-mixture of metal oxide particles dispersed in the acid copolymer.

9. The composition of any one of claims 1-8, wherein the metal oxide is calcium oxide particles.

10. The composition of any one of claims 1-9, wherein the acid copolymer is ethylene acrylic acid.

11. A method, the method comprising:

a polymer component comprising (i) a post-consumer resin and (ii) optionally an olefin-based polymer, the polymer component having an amount of at least one volatile heterocarbonyl species;

adding to the polymer component from 0.15 wt% to 15 wt% of an odor inhibitor comprising

(i)0.05 to 2 weight percent, based on the total weight of the composition, of a metal oxide having a band gap greater than 5.0 electron volts (eV), and

(ii)0.1 to 13 weight percent of an acid copolymer based on the total weight of the composition, the ratio of metal oxide to acid copolymer being from 1: 20 to 1: 1 to form an odor-reducing composition; and

neutralizing at least some of the volatile heterocarbonyl species with the odor inhibitor to form an odor-reduced composition.

12. The method of claim 11, comprising:

forming a reduced-odor composition exhibiting at least a 20% reduction in the amount of volatile heterocarbonyl species as measured by standardized gas chromatography compared to the polymer component without the odor inhibitor.

13. The method according to any one of claims 11-12, comprising

Dispersing the metal oxide particles in the acid copolymer to form an odor inhibitor premix prior to addition;

adding the odor inhibitor pre-mix to the polymer component; and

forming the reduced-odor composition.

Background

The environmental hazards posed by plastic waste are well known. Large-scale social efforts are used to recover and reuse plastic materials, commonly referred to as post-consumer resins (PCR). Efforts to reprocess and reintegrate PCR into usable consumer products continue to expand.

The inherent wasteful aspect of PCR means that PCR can be affected by malodour and can produce unpleasant taste when in contact with food. Common sources of objectionable taste and odor include volatile heterocarbonyl species and other chemicals inherent in PCR. There are many applications where it is desirable to mix PCR with virgin plastic. These applications require suppression of odors from PCR in order to be commercially viable.

Metal oxides, such as calcium oxide (CaO), are known to consume many molecules that produce taste and odor. All other factors being equal, it is well known that CaO concentration and odor suppression are directly related — that is, as CaO concentration increases in a given olefin-based polymer article, the effectiveness of odor suppression also increases. Also, it is well known that as the relative surface area of an adsorbent system increases, its activity and capacity also increase.

Although odor suppression increases with increasing CaO, there does exist a limit to the amount of CaO that can be effectively incorporated into olefin-based polymeric articles. For example, in the production of blown film, high levels of CaO particles can increase the build-up of the extrusion die lip, leading to film defects. High loadings of CaO particles can also increase haze, resulting in a decrease in the clarity and/or color of the olefin-based polymer film. High loadings of CaO particles can also adversely affect mechanical properties such as impact strength and film tear strength. Thus, the processing parameters and end-use mechanical requirements impose practical limits on the loading of the CaO particles in the olefin-based polymer composition.

Accordingly, there is a need for PCR-containing compositions with improved odor suppression while carrying suitable metal oxide (i.e., calcium oxide) loading to maintain processability, desired optical and desired mechanical properties for end-use applications. There is a further need for odor-inhibiting articles made from such PCR-containing polymer compositions.

Disclosure of Invention

The present disclosure provides a composition. In one embodiment, the composition comprises a polymer component and an odor inhibitor. The polymer component comprises (i) a post-consumer resin and (ii) optionally an olefin-based polymer. The composition further comprises 0.15 wt% to 15 wt% of an odor inhibitor. The odor inhibitor comprises (i)0.05 to 2 wt% of a metal oxide having a band gap greater than 5.0 electron volts (eV); (ii)0.1 to 13% by weight of an acid copolymer. The ratio of metal oxide to acid copolymer is from 1: 20 to 1: 1. The weight percentages are based on the total weight of the composition.

The present disclosure provides a method. In one embodiment, the method comprises providing a polymer component consisting of (i) a post-consumer resin (PCR) and (ii) an optional olefin-based polymer. The polymer component has an amount of at least one volatile heterocarbonyl species. The method includes adding 0.15 wt% to 15 wt% of an odor inhibitor to the polymer component. The odor inhibitor comprises (i)0.05 to 2 weight percent of a metal oxide having a band gap greater than 5.0 electron volts (eV), and (ii)0.1 to 13 weight percent of an acid copolymer. The ratio of metal oxide to acid copolymer is from 1: 20 to 1: 1. The method includes neutralizing at least some of the volatile heterocarbonyl species in the PCR with an odor inhibitor to form an odor-reducing composition. The weight percentages are based on the total weight of the odor-reducing composition.

Definition of

Any reference to the Periodic Table of Elements is the Periodic Table of Elements as published by CRC Press, Inc., 1990 and 1991. References to a group of elements in the table are represented by new symbols numbering the groups.

For purposes of united states patent practice, the contents of any referenced patent, patent application, or publication are incorporated by reference in their entirety (or its equivalent us version) particularly with respect to the disclosure of limitations (to the extent not inconsistent with any limitations specifically provided in this disclosure) and general knowledge in the art.

The numerical ranges disclosed herein include all values beginning with and including the lower and upper values. For ranges containing an exact value (e.g., 1 or 2, or 3 to 5, or 6, or 7), any subrange between any two exact values (e.g., 1 to 2; 2 to 6; 5 to 7; 3 to 7; 5 to 6, etc.) is included.

Unless indicated to the contrary, implicit from the context or customary in the art, all parts and percentages are by weight and all test methods are current as of the filing date of this disclosure.

As used herein, the term "blend" or "polymer blend" is a blend of two or more polymers. Such blends may or may not be miscible (not phase separated at the molecular level). The blend may or may not be phase separated. Such blends may or may not contain one or more domain configurations, as determined by transmission electron spectroscopy, light scattering, x-ray scattering, and other methods known in the art.

The term "composition" refers to a mixture of materials comprising the composition, as well as reaction products and decomposition products formed from the materials of the composition.

The terms "comprising," "including," "having," and derivatives thereof, are not intended to exclude the presence of any additional component, step or procedure, whether or not the component, step or procedure is specifically disclosed. For the avoidance of any doubt, unless stated to the contrary, all compositions claimed through use of the term "comprising" may include any additional agent, adjuvant, or compound, whether polymeric or otherwise. In contrast, the term "consisting essentially of excludes any other components, steps or procedures from any subsequently listed ranges, except for those that are not essential to operability. The term "consisting of" excludes any component, step, or procedure not specifically depicted or listed. Unless otherwise specified, the term "or" means the members listed individually as well as in any combination. The use of the singular includes the use of the plural and vice versa.

An "ethylene-based polymer" is a polymer that contains more than 50 weight percent (wt.%) polymerized ethylene monomer (based on the total amount of polymerizable monomers) and optionally may contain at least one comonomer. Ethylene-based polymers include ethylene homopolymers and ethylene copolymers (meaning units derived from ethylene and one or more comonomers). The terms "ethylene-based polymer" and "polyethylene" are used interchangeably. Non-limiting examples of ethylene-based polymers (polyethylenes) include Low Density Polyethylene (LDPE) and linear polyethylenes. Non-limiting examples of linear polyethylenes include Linear Low Density Polyethylene (LLDPE), Ultra Low Density Polyethylene (ULDPE), Very Low Density Polyethylene (VLDPE), multicomponent ethylene-based copolymers (EPE), ethylene/a-olefin multi-block copolymers (also known as Olefin Block Copolymers (OBC)), substantially linear or linear plastomers/elastomers, and High Density Polyethylene (HDPE). In general, polyethylene can be produced in a gas phase fluidized bed reactor, a liquid phase slurry process reactor, or a liquid phase solution process reactor using a heterogeneous catalyst system (e.g., ziegler-natta catalyst), a homogeneous catalyst system comprising a group 4 transition metal and a ligand structure (e.g., metallocene, non-metallocene metal-centered heteroaryl, isovalent aryloxyether, phosphinimine, etc.). Combinations of heterogeneous and/or homogeneous catalysts may also be used in a single reactor or dual reactor configuration.

An "ethylene plastomer/elastomer" is a substantially linear or linear ethylene/alpha-olefin copolymer containing a homogeneous short chain branch distribution comprising units derived from ethylene and units derived from at least one C₃-C₁₀Units of an alpha-olefin comonomer. Density of ethylene plastomer/elastomerFrom 0.870g/cc to 0.917 g/cc. Non-limiting examples of ethylene plastomers/elastomers include AFFINITY^TMPlastomers and elastomers (available from The Dow Chemical Company), EXACT^TMPlastomers (available from ExxonMobil Chemical), Tafmer^TM(available from Mitsui, Inc.), Nexlene^TM(available from SK chemical Co., Ltd.) and Lucene^TM(commercially available from LEJIN Chemicals (LG Chem Ltd.)).

"high density polyethylene" (or "HDPE") is an ethylene homopolymer or has at least one C₄-C₁₀Alpha-olefin comonomer or C₄-C₈An ethylene/alpha-olefin copolymer of an alpha-olefin comonomer and having a density of 0.940g/cc, or 0.945g/cc, or 0.950g/cc, 0.953g/cc to 0.955g/cc, or 0.960g/cc, or 0.965g/cc, or 0.970g/cc, or 0.975g/cc or 0.980 g/cc. The HDPE may be a unimodal copolymer or a multimodal copolymer. A "unimodal ethylene copolymer" is an ethylene/C copolymer having one distinct peak showing the molecular weight distribution in Gel Permeation Chromatography (GPC)₄-C₁₀An alpha-olefin copolymer. A "multimodal ethylene copolymer" is an ethylene/C copolymer having at least two distinct peaks showing a molecular weight distribution in GPC₄-C₁₀An alpha-olefin copolymer. Multimodal includes copolymers having two peaks (bimodal) as well as copolymers having more than two peaks. Non-limiting examples of HDPE include DOW^TMHigh Density Polyethylene (HDPE) resin (available from The Dow Chemical Company), ELITE^TMReinforced polyethylene resin (available from Dow chemical Co., Ltd.), CONTINUUM^TMBimodal polyethylene resin (available from Dow chemical Co., Ltd.), LUPOLEN^TM(available from LyondellBasell) and HDPE products from northern Europe chemical (Borealis), Enlishi (Ineos) and Exxon guan.

An "interpolymer" is a polymer prepared by polymerizing at least two different monomers. This generic term includes copolymers, which are commonly used to refer to polymers prepared from two different monomers, as well as polymers prepared from more than two different monomers, e.g., terpolymers, tetrapolymers, etc.

"Linear Low Density polyethylene" (or "LLDPE") is a linear ethylene/alpha-olefin copolymer containing a heterogeneous short chain branching distribution comprising units derived from ethylene and units derived from at least one C₃-C₁₀Alpha-olefins or C₄-C₈Units of an alpha-olefin comonomer. LLDPE is characterized by little, if any, long chain branching compared to conventional LDPE. The LLDPE has a density of from 0.910g/cc to less than 0.940 g/cc. Non-limiting examples of LLDPE include TUFLIN^TMLinear low density polyethylene resin (available from Dow chemical Co.), DOWLEX^TMPolyethylene resin (available from Dow chemical) and MARLEX^TMPolyethylene (available from Chevron Phillips).

"Low density polyethylene" (or "LDPE") is made of an ethylene homopolymer or comprises at least one C having a density of from 0.915g/cc to less than 0.940g/cc₃-C₁₀Alpha-olefins or C₄-C₈Ethylene/alpha-olefin copolymers of alpha-olefins and contain long chain branches with broad MWD. LDPE is typically produced by means of high pressure free radical polymerisation (tubular reactor or autoclave with free radical initiator). Non-limiting examples of LDPE include MarFlex^TM(Chevron Phillips), LUPOLEN^TM(LyondellBasell), and LDPE products from northern Europe chemical industry (Borealis), Enlishi (Ineos), Exxon guanil (ExxonMobil), and others.

"multicomponent ethylene-based copolymer" (or "EPE") comprising units derived from ethylene and units derived from at least one C₃-C₁₀Alpha-olefins or C₄-C₈Units of alpha-olefin comonomers as described in the patent references USP 6,111,023, USP 5,677,383 and USP 6,984,695. The EPE resin has a density of 0.905g/cc to 0.962 g/cc. Non-limiting examples of EPE resins include ELITE^TMReinforced polyethylene (available from Dow chemical Co.), ELITE AT^TMAdvanced technology resins (available from the Dow chemical company), SURPASS^TMPolyethylene (PE) resins (available from Norwalk chemical (Nova Chemicals)), and SMART^TM(commercially available from fresh Beijing)School company).

An "olefin-based polymer" or "polyolefin" is a polymer that contains more than 50 weight percent polymerized olefin monomer (based on the total amount of polymerizable monomers) and optionally may contain at least one comonomer. Non-limiting examples of olefin-based polymers include ethylene-based polymers and propylene-based polymers.

A "polymer" is a compound prepared by polymerizing monomers, of the same or different type, in polymerized form to provide multiple and/or repeating "units" or "combined and unit" that make up the polymer. Thus, the generic term polymer encompasses the term homopolymer, which is commonly used to refer to polymers prepared from only one type of monomer, and the term copolymer, which is commonly used to refer to polymers prepared from at least two types of monomers. Polymers also encompass all forms of copolymers, e.g., random copolymers, block copolymers, and the like. The terms "ethylene/α -olefin polymer" and "propylene/α -olefin polymer" indicate copolymers as described above prepared by polymerizing ethylene or propylene, respectively, with one or more additional polymerizable α -olefin monomers. It should be noted that although polymers are often referred to as being "made from" one or more particular monomers, "containing" a particular monomer content, based on "a particular monomer or type of monomer, and the like, in this context, the term" monomer "should be understood to refer to the polymerization residue of a particular monomer rather than to unpolymerized material. Generally, the polymers referred to herein are "units" based on the polymerized form of the corresponding monomer.

A "propylene-based polymer" is a polymer containing more than 50% by weight polymerized propylene monomers (based on the total amount of polymerizable monomers) and optionally may contain at least one comonomer. Propylene-based polymers include propylene homopolymers and propylene copolymers (meaning units derived from propylene and one or more comonomers). The terms "propylene-based polymer" and "polypropylene" may be used interchangeably. Non-limiting examples of suitable propylene copolymers include propylene impact copolymers and propylene random copolymers.

"ultra low density polyethylene" (or "ULDPE') and "very low density polyethylene" (or "VLDPE") are each linear ethylene/alpha-olefin copolymers containing a heterogeneous short chain branching distribution comprising units derived from ethylene and units derived from at least one C₃-C₁₀Units of an alpha-olefin comonomer. ULDPE and VLDPE each have a density of 0.885g/cc to 0.915 g/cc. Non-limiting examples of ULDPE and VLDPE include ATTANE^TMUltra low density polyethylene resin (available from Dow chemical) and FLEXOMER^TMVery low density polyethylene resins (available from the dow chemical company).

Test method

D10, D50, and D90 Particle sizes were measured using a Coulter LS 230 Laser Scattering Particle Sizer (Laser Light Scattering Particle Sizer) available from Coulter Corporation (Coulter Corporation). The D10 particle size is the particle diameter at which 10% of the mass of the powder consists of particles with a diameter smaller than this. The D50 particle size is the diameter of a particle for which 50% of the mass of the powder consists of particles with a diameter smaller than this value and 50% of the mass of the powder consists of particles with a diameter larger than this value. The D90 particle size is the particle diameter at which 90% of the mass of the powder consists of particles with a diameter smaller than this. The average volume average particle size was measured using a Coulter LS 230 laser scattering particle sizer available from Coulter. The particle size distribution was calculated according to equation a:

density is measured according to ASTM D792, method B. The results are reported in grams per cubic centimeter (g/cc).

Differential Scanning Calorimetry (DSC)Differential Scanning Calorimetry (DSC) can be used to measure the melting, crystallization and glass transition behavior of polymers over a wide temperature range. This analysis is performed, for example, using a TA instrument (TA Instruments) Q1000DSC equipped with a Refrigerated Cooling System (RCS) and an autosampler. During the test, a nitrogen purge gas flow rate of 50 ml/min was used. Melt pressing each sample into a film at about 175 ℃; the molten sample was then air cooled to room temperature (about 25 ℃). 3-10mg of 6mm diameter are withdrawn from the cooled polymerThe samples were weighed, placed in a light aluminum pan (approximately 50mg), and crimped shut. Analysis is then performed to determine its thermal properties.

The thermal behavior of the sample is determined by ramping the sample temperature up and down to produce a heat flow versus temperature curve. First, the sample was rapidly heated to 180 ℃ and held isothermal for 3 minutes in order to remove its thermal history. Next, the sample was cooled to-40 ℃ at a cooling rate of 10 ℃/min and held isothermal for 3 minutes at-40 ℃. Next, the sample was heated to 180 ℃ (this was a "second heat" ramp) at a 10 ℃/minute heating rate. The cooling and second heating profiles were recorded. The cooling curve was analyzed by setting a baseline end point from the start of crystallization to-20 ℃. The heating curve was analyzed by setting a baseline end point from-20 ℃ to the end of melting. The values determined are the extrapolated onset of melting Tm and the extrapolated onset of crystallization Tc. The heat of fusion (Hf) (in joules per gram) and the calculated% crystallinity for the polyethylene samples was performed using the following equation: degree of crystallinity [% ] ((Hf)/292J/g) × 100. The glass transition temperature Tg is determined from the DSC heating curve in which half of the sample has been subjected to a liquid heat capacity, as described in Bernhard Wunderlich, basis for thermal analysis in thermal characterization of polymeric materials 92, 278. 279(Edith A. Turi edition, 2 nd edition, 1997). Baselines were drawn from below and above the glass transition region and extrapolated through the Tg region. The temperature at which the heat capacity of the sample is midway between these baselines is the Tg.

Melt Flow Rate (MFR) in g/10min was measured according to ASTM D1238(230 ℃/2.16 kg).

Melt Index (MI) in g/10min was measured according to ASTM D1238(190 ℃/2.16kg) (I2).

Standardized gas chromatography for measuring odor reduction.Odor suppression is the ability of a composition to reduce or otherwise neutralize volatile heterocarbonyl species in the composition. Gas chromatography was used to compare the amount of volatile heterocarbonyl species in the headspace gas surrounding (i) a sample of the polymer component without the odor inhibitor (hereinafter "pure polymer component") with (ii) the headspace gas surrounding a second sample with the same polymer component as the pure polymer componentThe gas, the second sample also contains an amount of odor inhibitor. The GC detection of the headspace gas of the first sample (pure polymer component) was compared to the GC detection of the headspace gas of the second sample (polymer component with odor inhibitor) using equation (1) below.

Equation (1)

(GC (PO with odor inhibitor at t) -GC (pure PO at t))/GC (pure PO at t) × 100 ═ percentage odor reduction

Wherein GC is a gas chromatographic measurement of one or more predetermined carbonyl-containing volatile species;

PO is a polymer component; and

t is a predetermined time interval.

Equation (1) is hereinafter referred to as "normalized gas chromatography".

Standardized gas chromatography was performed as follows. The percentage concentration that causes the odor of the volatile heterocarbonyl species was measured by gas chromatography/mass spectrometry (GC/MS).

An Agilent 7890A Gas Chromatograph (GC) was used with a column DB-1701, 30mx0.32mm ID x1 μm film thickness, helium as a carrier gas, at a constant flow rate of 2.0 mL/min. The oven of the GC was programmed to remain at 50 ℃ for 3.5 min. The inlet split temperature was 150 ℃ and the split ratio was 10: 1. The headspace gas injection volume was 1.0mL and was injected using an air tight syringe. The transmission line was maintained at 250 ℃.

The column outlet was connected in parallel to the mass spectrometer and Flame Ionization Detector (FID) by an Agilent 2-way non-purging flow splitter (part number G3181B). The mass spectrometer was operated under the following conditions: scan 14-200m/z (ei), source temperature 230 ℃, quadrupole temperature 150 ℃, EM voltage 2447V, electron energy-70 eV, 2 samples, and threshold 0.

The FID was run under the following conditions: 250 ℃, 30mL/min hydrogen flow, 400mL/min air flow, and 45mL helium/min tail gas sparge.

The samples were prepared by adding 2 grams of sample particles to a separate headspace vial. No additional chemicals were added to the headspace because all volatile heterocarbonyl species in the headspace were evaporated from the PCR sample. The samples were sealed at room temperature for 20 hours (hrs) and shaken for 4 hours.

Headspace gas was removed from the vial at predetermined time intervals to assess odor suppression capability. The "percent odor reduction" value (or "% odor reduction") was calculated by the following method: (a) the test sample concentration is subtracted from the control (pure polymer component, PCR + polyolefin) concentration of each volatile heterocarbonyl species (i.e., potential odor molecule), and then (b) the remainder of (a) is divided by the control concentration using equation (1) above.

Detailed Description

The present disclosure provides a composition. In one embodiment, a composition for suppressing odor is provided and includes a polymer component and an odor inhibitor. The polymer component comprises a post-consumer resin (PCR) and optionally an olefin-based polymer. The composition comprises 0.15 wt% to 15 wt% of the odor inhibitor, based on the total weight of the composition. The odor inhibitor comprises (i) from 0.05 wt% to 2 wt%, based on the total weight of the composition, of a metal oxide having a band gap greater than 5.0 electron volts (eV). The odor inhibitor further comprises (ii)0.1 wt% to 13 wt% of an acid copolymer, based on the total weight of the composition. The ratio of metal oxide to acid copolymer is from 1: 20 to 1: 1.

A (i) post-consumer resin

The polymer component of the composition of the present invention comprises a post-consumer resin (PCR). The PCR contains a certain amount of volatile heterocarbonyl species. The term "post-consumer resin" or "PCR" is a polymeric material that has previously been used as consumer packaging or industrial packaging. In other words, PCR is waste plastic. PCR is typically a polyolefin, and particularly polyethylene. PCR typically involves HDPE packaging such as bottles (milk cans, juice containers), LDPE/LLDPE packaging such as films. Polymerase chain reaction also includes residues from its original use, such as paper, adhesives, inks, nylon, ethylene vinyl alcohol (EVOH), polyethylene terephthalate (PET), and other odor causing substances.

Non-limiting examples of suitable PCR include EcoPrime, tradename, by Envision Plastics, N.C.^TM、PRISMA^TMNatural HDPE PCR Resins, Mixed Color and Black HDPE PCR Resins; PCRs sold by KW Plastics, Alabama, USA under the tradenames KWR101-150, KWR101-150-M5-BLK, KWR101-150-M10 BLK, KWR102-8812 BLK, KWR102, KWR102LVW, KWR105, KW620, KWR102-M4, KWR-105M2, KWR105M4, KWR621 FDA, KWR621-20-FDA, KW308A, KW621-T10, KW621-T20, KW622-20, KW622-35, KW627C, KW1250G and KWBK 10-NB. In one embodiment, the polymer component consists of 100 wt% of the PCR, wherein the weight percentages are based on the total weight of the polymer component.

A (ii) polyolefin-based polymer

In addition to PCR, the polymer component can optionally include an olefin-based polymer. In one embodiment, the olefin-based polymer may be a propylene-based polymer or an ethylene-based polymer. The olefin-based polymer may or may not contain an amount of volatile heterocarbonyl species. Non-limiting examples of propylene-based polymers include propylene copolymers, propylene homopolymers, and combinations thereof. In one embodiment, the propylene-based polymer is a propylene/α -olefin copolymer. Non-limiting examples of suitable alpha-olefins include C₂And C₄-C₂₀Alpha-olefins, or C₄-C₁₀Alpha-olefins, or C₄-C₈An alpha-olefin. Representative alpha-olefins include ethylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, and 1-octene.

In one embodiment, the propylene/α -olefin copolymer is a propylene/ethylene copolymer containing greater than 50 wt% of units derived from propylene, or a propylene/ethylene copolymer containing 51 wt%, or 55 wt%, or 60 wt% to 70 wt%, or 80 wt%, or 90 wt%, or 95 wt%, or 99 wt% of units derived from propylene, based on the weight of the propylene/ethylene copolymer. The propylene/ethylene copolymer contains a complementary amount of units derived from ethylene, or 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% of units derived from ethylene, based on the weight of the propylene/ethylene copolymer.

In one embodiment, the ethylene-based polymer is an ethylene-based copolymer. The ethylene-based polymer may be an ethylene homopolymer or an ethylene/alpha-olefin copolymer.

In one embodiment, the ethylene-based polymer is an ethylene/a-olefin copolymer. Non-limiting examples of suitable alpha-olefins include C₃-C₂₀Alpha-olefins, or C₄-C₁₀Alpha-olefins, or C₄-C₈An alpha-olefin. Representative alpha-olefins include propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, and 1-octene.

In one embodiment, the ethylene/alpha-olefin copolymer is as an ethylene/C₄-C₈HDPE of an alpha-olefin copolymer. HDPE has one, some or all of the following properties:

(i) a density of 0.940g/cc to 0.960 g/cc; and/or

(ii) Tm from 128 ℃ to 132 ℃; and/or

(ii) A melt index of 0.5g/10min to 2.0g/10 min.

A non-limiting example of a suitable HDPE is DMDA-1250, available from DowDuPont.

In one embodiment, the polymer component comprises a PCR blended with an olefin-based polymer that is not a PCR. In other words, PCR is mixed with "virgin olefin-based polymer". The raw olefin-based polymer may or may not contain an amount of volatile heterocarbonyl species. The polymer component may contain 5 wt.% or 20 wt.% or 30 wt.% or 40 wt.% or 50 wt.% to 60 wt.% or 70 wt.% or 80 wt.% or 95 wt.% of the original olefin-based polymer, or 95 wt.% or 80 wt.% or 70 wt.% or 60 wt.% or 50 wt.% to 40 wt.% or 30 wt.% or 20 wt.% or 5 wt.% of the original olefin-based polymer; and/or

B. Odour inhibitors

The compositions of the present invention comprise an odor inhibitor. The odor inhibitor is a mixture of a metal oxide (Bi) and an acid copolymer (Bii).

B (i) a metal oxide

The odor inhibitor comprises a metal oxide. The band gap of the metal oxide is greater than 5.0 electron volts (eV). As used herein, a "bandgap" is a range of energies where no electronic state is present in a solid. The band gap is the energy required to promote valence electrons to conduction electrons, which can move freely within the crystal lattice and conduct current as charge carriers. "Electron volts" or "eV" is approximately equal to 1.6X 10^-19Units of energy in joules. The band gap of metal oxides is described in detail in Surface and Nanomolecular Catalysis, Ryan Richards (ed), Taylor & Francis 2006, the contents of which are incorporated herein by reference.

Without being bound by a particular theory, it is believed that the large band gap (i.e., greater than 5.0eV) translates into bonds with very little covalent nature in which electrons are shared disproportionately. This may result in a net positive charge on the metal ions in the crystal lattice and a net negative charge on the oxide ions. Thus, the magnitude of the charge can be proportional to the bandgap. Thus, the electron-deficient metal ion can freely act as a lewis acid, accepting electrons from the weakly basic moiety present in the volatile heterocarbonyl odor molecule. In addition, the crystalline oxide ion may be able to act as a lewis base, providing electrons to the slightly acidic portion of the volatile heterocarbonyl odor molecule.

Table A below provides band gap values for several metal oxides from Surface and Nanomolecular catalysis, Ryan Richards (ed), Taylor & Francis 2006.

TABLE A band gap thresholds for some metal oxides

Metal oxides	Band gap (eV)
		MgO	7.7
CaO	6.9
		SrO	5.3
BaO	4.4
		ZnO	～3.2
TiO2	～3.2
		Al2O3	～7
CuO	1.2
		Cu2O	2.1

In one embodiment, the metal oxide is in the form of particles (powder), with a band gap greater than 5.0eV, and is selected from the group consisting of calcium oxide (CaO), magnesium oxide (MgO), strontium oxide (SrO), aluminum oxide Al₂O₃And combinations thereof.

In one embodiment, the metal oxide is in the form of particles (powder) with a band gap greater than 6.0 eV. In a further embodiment, the metal oxide is selected from the group consisting of calcium oxide (CaO), magnesium oxide (MgO), and combinations thereof. In yet another embodiment, the metal oxide is calcium oxide (CaO).

In one embodiment, the metal oxide is calcium oxide (6.9eV) in particulate (powder) form having a D50 particle size of 100nm, or 125nm, or 150nm to 250nm, or 500nm, or 1000nm, or 3000 nm. In another embodiment, the calcium oxide powder has a D50 of 100nm to 3000nm, or 125nm to 1000nm, or 150nm to 500nm, or 175nm to 250nm, or 125 to 160nm, or a D50 of 150 to 160 nm.

In one embodiment, the metal oxide is hygroscopic and includes surface-bound moisture. In a further embodiment, the metal oxide is CaO. H₂O。

B (ii) acid copolymer

The odor inhibitor comprises an acid copolymer and a metal oxide. As used herein, the term "acid copolymer" (or "AC") is a copolymer comprising (i) ethylene monomer and (ii) a carboxylic acid comonomer or ester derivative thereof (hereinafter "acid comonomer"). The acid copolymer comprises the acid comonomer in an amount of 1 wt%, or 5 wt%, or 10 wt%, or 15 wt% to 20 wt%, or 25 wt%, or 30 wt% and the reciprocal weight of the ethylene monomer. It is understood that the acid copolymer comprises greater than 50 wt% or greater than 60 wt% of ethylene monomer. In further embodiments, the acid copolymer comprises from 1 wt% to 30 wt% of the acid comonomer (and the inverse amount of ethylene), or from 5 wt% to 30 wt% of the acid comonomer (and the inverse amount of ethylene), or from 10 wt% to 25 wt% of the acid comonomer (and the inverse amount of ethylene), or from 15 wt% to 20 wt% of the acid comonomer (and the inverse amount of ethylene), or from 5 wt% to 10 wt% of the acid comonomer (and the inverse amount of ethylene).

In one embodiment, the acid comonomer is an acrylate-based moiety. Non-limiting examples of suitable acid copolymers in which the acid comonomer is an acrylate-based moiety include ethylene ethyl acrylate copolymer (EEA), ethylene butyl acrylate copolymer (EBA), ethylene acrylic acid copolymer (EAA), ethylene/(meth) acrylic acid copolymer (EMA), and combinations thereof.

In one embodiment, the acid copolymer is an ethylene/acrylic acid copolymer having from 5 wt% to 30 wt% acrylic acid comonomer. Non-limiting examples of suitable acid copolymersExamples include those available from E.I.du Pont de Nemours and Company (Wilmington, Delaware)A polymer.

In one embodiment, the odor inhibitor is a premix of metal oxide powder dispersed in the acid copolymer. Mechanical blending and/or melt blending can be used to uniformly disperse the metal oxide particles throughout the acid copolymer. The premix is subsequently added as odour inhibitor to the polymer component (a).

C. Composition comprising a metal oxide and a metal oxide

In one embodiment, the inventive composition comprises (a)85 to 99.85 wt% of a polymer component and (B)15 wt%, or 13 wt%, or 11 wt%, or 10 wt%, or 9 wt%, or 7 wt%, or 5 wt% to 2 wt%, or 1 wt%, or 0.6 wt%, or 0.5 wt%, or 0.3 wt%, or 0.2 wt%, 0.15 wt% of an odor inhibitor. The odor inhibitor is mixed or otherwise blended into the polymer component matrix. The odor inhibitor comprises (i)0.05 wt%, or 0.1 wt%, or 0.15 wt%, or 0.2 wt%, or 0.25 wt%, or 0.3 wt%, or 0.4 wt%, or 0.5 wt%, or 0.7 wt%, or 0.9 wt% to 1.0 wt%, or 1.5 wt%, or 2 wt% of metal oxide particles (having a band gap greater than 5.0 eV); and (ii)0.1 wt%, or 0.5 wt%, or 1.0 wt%, or 3 wt%, or 5 wt%, or 7 wt%, or 9 wt% to 10 wt%, or 11 wt%, or 13 wt% of an acid copolymer. The weight percentages are based on the total weight of the composition. The ratio of metal oxide to acid copolymer is 1: 20, or 1: 15, or 1: 10, or 1: 8, or 1: 6 to 1: 4, or 1: 2, or 1: 1. The composition exhibits at least a 5% reduction in at least one volatile heterocarbonyl species as compared to the polymer component without the odor inhibitor (i.e., the polymer component alone).

The reduction in volatile heterocarbonyl species is a quantitative comparison of (i) the amount of the predetermined volatile heterocarbonyl species present in the polymer component (i.e., polymer component (a) without any odor inhibitor) to (ii) the amount of the predetermined volatile heterocarbonyl species in the composition of the present invention comprised of (a) the polymer component and (B) the odor inhibitor. The reduction in volatile heterocarbonyl species is measured by normalized gas chromatography as previously disclosed herein.

As used herein, a "volatile heterocarbonyl" is a hydrocarbon compound (i) having from 1 carbon atom to 16 carbon atoms and comprising at least one heteroatom selected from S, O, N and/or P, (ii) and having a molecular weight of from 30 daltons to 250 daltons, (iii) and having a vapor pressure greater than 0.01 millimeters of mercury (mm Hg) at standard temperature and pressure or "STP". In one embodiment, the volatile heterocarbonyl species has CO bonds and/or C ═ O bonds. Non-limiting examples of volatile heterocarbonyl species include volatile C₁-C₁₆Aldehyde, volatile C₁-C₁₆Ketone, volatile C₁-C₁₆Carboxylic acid, volatile C₁-C₁₆Ester, volatile C₁-C₁₆Alcohol, volatile C₁-C₁₆Ethers and combinations thereof.

Volatility C₁-C₁₆Non-limiting examples of aldehydes include formaldehyde, acetaldehyde, propionaldehyde, hexanal, furfural, heptaldehyde, benzaldehyde, octanal, nonanal, decanal, undecanal, and combinations thereof.

Volatility C₃-C₁₆Non-limiting examples of ketones include 2-pentanone, 2-hexanone, 2-octanone, 2-nonanone, 2-decanone, 2-acetophenone, 2-undecanone, and combinations thereof.

Volatility C₁-C₁₆Non-limiting examples of carboxylic acids include hexanoic acid, butyric acid, heptanoic acid, octanoic acid, benzoic acid, nonanoic acid, decanoic acid, and combinations thereof.

Volatility C₁-C₁₆Non-limiting examples of alcohols include methanol, ethanol, propanol, 2-methylbutanol, and combinations thereof.

Volatility C₁-C₁₆Non-limiting examples of ethers include Tetrahydrofuran (THF) and its alkyl derivatives.

In one embodiment, the composition comprises (a)97 to 98.9 wt% of the polymer component. The composition comprises 3 wt%, or 2.8 wt% to 1.1 wt% of an odor inhibitor, wherein the odor inhibitor comprises (Bi)0.01 wt%, or 0.05 wt%, or 0.07 wt% to 0.5 wt%, or 0.7 wt%, or 0.9 wt% of a metal oxide of CaO particles, and (Bii) an acid copolymer of an amount of 0.1, or 0.2, or 0.5, or 0.7, or 0.9 to 1.0, or 1.3, or 1.5, or 1.7, or 1.9 and a ratio of metal oxide to acid copolymer of 1: 10, or 1: 8, or 1: 6 to 1: 4, or 1: 2, or 1: 1. The weight percentages are based on the total weight of the composition. The composition has at least a 20% reduction in at least one volatile heterocarbonyl species as compared to the polymer component (a) without the odor inhibitor. The reduction in volatile heterocarbonyl species is measured by standardized gas chromatography.

In one embodiment, the composition comprises (a)98.5 to 99.0 wt% of a polymer component. The composition comprises 1.5 wt%, or 1.3 wt% to 1.1 wt%, or 1.0 wt% of an odor inhibitor, wherein the odor inhibitor comprises (Bi)0.05 wt%, or 0.08 wt% to 0.1 wt%, or 0.13 wt%, or 0.15 wt% of a metal oxide of CaO particles, and (Bii) an acid copolymer of (Bi) 1.0 wt%, or 1.1 wt% to 1.2 wt%, or 1.3 wt% of an ethylene/acrylic acid copolymer and a ratio of metal oxide to acid copolymer of 1: 15, or 1: 12 to 1: 10, or 1: 8, hereinafter referred to as composition 1. The weight percentages are based on the total weight of the composition. Composition 1 reduced at least one volatile heterocarbonyl species by 10% to 35% after a 20 hour exposure time compared to olefin-based polymer (a) without odor inhibitor. The reduction in volatile heterocarbonyl species is measured by standardized gas chromatography.

In one embodiment, composition 1 includes (a)98.9 wt% of the polymer component and 1.1 wt% of the odor inhibitor. Polymer component (a) was 90 wt% ethylene-based polymer blended with 10 wt% PCR. The odor inhibitor contained (Bi) a metal oxide of CaO particles in an amount of 0.1% by weight and (Bii) an ethylene/acrylic acid copolymer in an amount of 1.0% by weight and an acid copolymer in a ratio of metal oxide to acid copolymer of 1: 10. The aldehyde of composition 1 was reduced by greater than 20% compared to the amount of aldehyde present in polymer component (a) alone. Percent reduction of aldehyde was measured by standardized gas chromatography.

D. Applications of

The compositions of the present invention may be used in any application where the presence of an odor or taste causing agent from a polymeric material, particularly an olefin-based polymer, is to be used in consumer applications. Non-limiting examples of suitable applications for the compositions of the present invention include vehicle interiors, textiles, and food packaging, including lids, closures, wraps, and bottles.

Surprisingly, the composition of the present invention (i.e., composition 1) exhibited the same or better odor inhibition capability without compromising processability and without compromising film performance. Applicants found that metal oxides with a band gap greater than 5.0eV act synergistically with the acid copolymer to improve odor suppression while using less total metal oxide (and less CaO) compared to polymer matrix systems containing only metal oxides. The ability of the acid copolymer to synergistically improve odor suppression when combined with metal oxides having a band gap greater than 5.0eV, particularly CaO, is unexpected.

The present disclosure provides a method. In one embodiment, the method comprises providing polymer component (a). Polymer component (a) includes (i) PCR, (ii) an optional olefin-based polymer, and (iii) has an amount of at least one volatile carbonyl-containing material. The method comprises adding 0.15 to 15 wt% of an odor inhibitor (B) to the polymer component (a). The odor inhibitor (B) comprises (Bi)0.05 to 2 weight percent of a metal oxide having a band gap greater than 5.0 electron volts (eV), and (Bii)0.1 to 13 weight percent of an acid copolymer, the ratio of metal oxide to acid copolymer being from 1: 20 to 1: 1, to form the odor reducing composition. The method comprises neutralizing at least some of the volatile heterocarbonyl species in polymer component (a) with an odor inhibitor to form an odor-reducing composition. The weight percentages are based on the total weight of the odor-reducing composition.

In one embodiment, the method comprises forming an odor-reducing composition that has at least a 20% reduction in the amount of volatile heterocarbonyl species as compared to the polymer component (a) without the odor inhibitor, as measured by standardized gas chromatography.

In one embodiment, the method comprises dispersing the metal oxide particles in the acid copolymer prior to addition to form the odor inhibitor premix. The method comprises adding an odor inhibitor premix to polymer component (a) to form an odor-reducing composition.

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

Examples

The materials used in the examples are provided in table 1 below.

TABLE 1

1. Sample preparation

Melt processing: a modified version of ASTM D1238, using a Tinius Olsen MP600 extrusion plastometer, set at 190 ℃ and weighing 10 Kg. The strands were collected and cut into small pieces of about 1cm, and then reintroduced into the plastometer and extruded again (to facilitate more mixing). The resulting second strand was cut into pieces of-1 cm and immediately placed into a glass vial sealed with a PTFE cap.

2. Odor suppression-reduction of volatile heterocarbonyl species

The sample was prepared by adding 2 grams of sample pellets to isolate a headspace vial. A0.5 mL, 1700ppmv sample of propionaldehyde was added to each headspace sample bottle. The samples were sealed at room temperature for 20 hours and then shaken for 4 hours. The headspace gas was removed for testing as described above.

A comparative sample (CS1) was prepared. CS1 is a control sample containing 90 wt.% DMDA1250(HDPE) and 10 wt.% of the polymeric component of the PCR and no odor inhibitor.

IE1 is an inventive example of the inventive composition consisting of 88.9 wt.% DMDA1250(HDPE) and 10 wt.% PCR and 1.1 wt.% odor inhibitor.

Table 2 reduction of headspace chemical concentration species as measured by GC composition (all results normalized to a control sample, CS 1).

TABLE 2

All weight percents based on the total weight of the components

The normalized gas chromatograph is determined using equation (1) as follows:

(GC_{(20 h aldehyde, CS1)}-GC_{(20 hours of aldehyde, IE1)})/GC_{(20 h aldehyde, CS1)}*100；

Wherein GC is_{(20 h aldehyde, CS1)}Is the area under the curve associated with the aldehyde and t is the time point of exposure to the gas for 20 hours, which has volatilized from an equivalent amount of post-consumer resin used with CS 1. Standardized gas chromatography equation (1) was used for ketones, alcohols, THF and THF derivatives in the same manner as the aldehydes set forth in this paragraph.

It is known that the odor inhibiting ability of CaO is linear, and thus the more CaO that is added to a polyolefin, the greater the odor inhibiting effect. However, high loadings (greater than 5 wt%) of CaO are disadvantageous because metal oxides, particularly CaO, can interfere with the melt processing of polyolefins.

In Table 2, IE1(1.1 wt% odour inhibitor, 0.1 wt% CaO and 1.0 wt% CaO: AC ratio of 1: 10) shows that at small loads (less than 0.2 wt% CaO and in IE1 specifically 0.1 wt% CaO) the odour inhibitor combined with the 1: 10 CaO: AC ratio showed significant odour inhibition (reduction greater than 20%) after 20 hours.

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.