Polymeric materials

Abstract

A method of treating a mass of polymeric material which may comprises recycled polystyrene or recycled polyolefin, to reduce the odour of the mass, comprises: (i) selecting a first mass comprising polymeric material; and (ii) contacting the first mass with a zeolite Y; wherein said zeolite Y has a Si:AI molar in the range 5.0:1 to 100:1. A mixture in the form of a product, for example a moulded article, pellets or granules which comprises polymeric material and zeolite Y is described as is a formulation for use in the method.

Description

[0001] Polymeric Materials P45443 This invention relates to polymeric materials and particularly, although not exclusively, relates to a formulation for addition to polymeric material comprising recyclate to reduce the levels of odour causing species which may be released from the recyclate and facilitate the use of higher levels of recyclate in products. Legislation and brand-owner targets mandate increased recycle content usage in polymeric materials. However, recyclate, such as polyolefin (PO) post consumer resin (PCR) , is contaminated with a wide range of malodour causing species. The odour arises from a combination of materials in contact with the polymer during its lifecycle, foreign contamination and breakdown of such species by the action of heat, light, microbial and other degradation pathways and degradation of the polymer during processing. As a result, mechanically recycled PO (rPO) has an objectionable odour, limiting its application in markets with organoleptic requirements. Recycling of other polymeric materials such as Acrylonitrile Butadiene Styrene (ABS), Polyvinyl Butyryl (PVB), Polyvinyl Chloride (PVC), Acrylonitrile Styrene Acrylate (ASA), Polymethylmethacrylate (PMMA), polystyrene (PS) or polyolefin (PO) may also be made more difficult due to contamination with malodour-causing species. The above problems may be addressed, with the aim of reducing the objectionable odour associated with recycled polymeric materials, such as rPO, as follows: (i) Incorporating an adsorbent into the rPO. However, in this solution, adsorption is disadvantageously proportional to temperature and the masterbatch tends to impact density and other polymer properties. Thus, the solution has poor efficacy and limited effectiveness. (ii) Incorporating a reactive masterbatch, for example zinc ricinoleate or Triple A™ supplied by ColorMatrix into the rPO. However, in this solution, there is high chemo selectivity for individual species meaning there may be no effect on the majority of odour-active species in rPO. Furthermore, new odour species may be generated and, additionally, high let- down-ratios are required. (iii) Thermal physical processing, such as vacuum degassing of the rPO, or hot air / nitrogen stripping. However, disadvantageously, these processes require significant upstream investment and are costly. Furthermore, it is challenging to remove less volatile species. (iv) Chemical recycling of the rPO, for example using chemical solvents or processes. This is an early stage technology which requires substantial capital investment. (v) The use of a material loaded with an aqueous species that can be incorporated in the extrusion process to accelerate the removal of odour material via the vacuum port. It is an object of preferred embodiments of the present invention to address the above-described problems. It is an object of preferred embodiments of the present invention to provide a method whereby increased levels of recyclate may be used. It is an object of preferred embodiments of the present invention to provide a means of reducing malodour associated with recyclate. According to a first aspect of the present invention, there is provided a method of treating a mass of polymeric material, the method comprising: (i) selecting a first mass comprising a polymeric material; and (ii) contacting said first mass with a zeolite Y. Said zeolite Y is suitably a zeolite Y as defined by the International Zeolite Association (IZA). Thus, it suitably has a FAU framework. Said zeolite Y suitably has a Si:AI molar ratio of at least 3.0, preferably at least 4.0, more preferably at least 5.0. Said molar ratio may be at least 5.1:1 or at least 5.2:1. Said molar ratio may be in the range 5.0:1 to 100:1, preferably in the range 5.1:1 to 100:1, more preferably in the range 5.1:1 to 90:1 or in the range 5.2:1 to 85:1. In some cases, said ratio may be in the range 5.0:1 to 10:1. Said zeolite Y may have a counterion selected from H+, Na+and NH4+. Said counterion is preferably selected from H+and NH4+. Said zeolite Y may have a surface area of at least 410 m2 / g, suitably at least 450 m2 / g, preferably at least 500 m2 / g, more preferably at least 600 m2 / g and, especially, at least 650 m2 / g. In some cases, said surface area may be at least 700 m2 / g. The surface area may be less than 950 m2 / g or less than 800 m2 / g. The surface area may be in the range 410 to 950 m2 / g. Surface area described herein may be measured by N2 adsorption using Brunauer-Emmett-Teller (BET) surface area analysis. Preferred zeolites have strong Bronstead activity which may be assessed by measurement, using of a pH meter, of an aqueous slurry of a candidate zeolite per se. Preferably, said method is a method of treating a mass of polymeric material to reduce the odour of the mass. Said method may comprise treating said first mass to produce a mass of polymeric material which has a reduced odour compared to the odour associated with the first mass of polymeric material selected in step (i). For example, the method may be used to treat said mass of polymeric material to reduce the concentration of species which have a high odour activity value. In some cases, the method may be used to reduce the concentration of species to less than their sensory threshold. Said method may comprise treating said first mass to produce a mass of polymeric material which has a reduced level of volatile emissions. For example, after treatment of said first mass, the total terpinene content in said first mass, suitably assessed as described in Assessment #1, may be reduced. In general, the content of other species of high odour activity may be reduced as illustrated in the examples which follow. Said method preferably comprises treating a first mass which comprises recycled polymeric material. The method may enable high levels of recycled polymeric materials to be used in producing articles than hitherto. The method may comprise, in said step (i), selecting a first mass of polymeric material. Said recycled polymeric material may be Acrylonitrile Butadiene Styrene (ABS), Polyvinyl Butyryl (PVB), Polyvinyl Chloride (PVC), Acrylonitrile Styrene Acrylate (ASA), Polymethylmethacrylate (PMMA), polystyrene (PS) or polyolefin (PO). In an embodiment A1, said polymeric material in said first mass may include at least 90 wt%, at least 95 wt% or at least 99 wt% of recycled polymeric material. Said recycled polymeric material may be recycled polystyrene or recycled polyolefin, for example polyethylene and / or polypropylene. In said embodiment A1, said first mass may include at least 90 wt%, at least 95 wt% or at least 99 wt% of recycled polymeric material. In this case, the recycled polymeric material may comprise polystyrene or polyolefin (but preferably not a mixture of polystyrene and polyolefin). When said recycled polymeric material comprises polyolefin, it may comprise at least 50% of polyethylene and / or at least 50 wt% of polypropylene. In some embodiments, when said recycled polymeric material comprises polyolefin, it may comprise at least 90%, at least 95 wt% or at least 99 wt% polyethylene or at least 90 wt%, at least 95 wt% or at least 99 wt% of polypropylene. In some cases, said recycled polymeric material may comprise a mixture of polyolefins. In embodiment A1, pellets may be produced incorporating said zeolite, wherein said pellets may comprise high levels of recycled polymeric material which suitably has reduced odour. Such pellets may then be used in downstream processes, for example being mixed with virgin resin and a moulded article produced there from. In an embodiment A2, said first mass may comprise a first polymeric material and recycled polymeric material. Unless otherwise stated herein, said recycled polymeric material may comprise scrap polymeric material, post-consumer recycle (PCR) and / or post-industrial recycle (PIR). Said recycled polymeric material may comprise recycled polyolefin, for example recycled polyethylene and / or polypropylene. Said recycled polymeric material may comprise PCR. In said method, preferably, said first mass is not subjected to devolatilization after step (i). Said first mass is preferably not subjected to devolatilization before step (i). The term “devolatilization” may refer to a process in which undesired volatile contaminants (e.g. dissolved gasses, solvent, unreacted monomer, etc.) are removed from a polymer melt or solution. A devolatilization process is generally driven by superheating the volatile component of the polymer melt / solution, in a screw extruder, then subsequently exposing the melt / solution to a rapid decompression. Devolatilization is costly and time-consuming to undertake; avoiding the need for devolatilization may be commercially advantageous. Said first polymeric material may comprise polystyrene or polyolefin for example polyethylene and / or polypropylene. Said first polymeric material preferably does not include any recycled polymeric material, for example it does not include any PCR. Said first polymeric material may comprise virgin polymeric material, for example virgin polystyrene or virgin polyolefin. Said first polymeric material may be virgin polyethylene or virgin polypropylene. It preferably comprises virgin polyethylene. Said first polymeric material may comprise at least 80 wt%, at least 90 wt% or at least 95 wt% of virgin polystyrene or virgin polyolefin. Said first polymeric material may comprise at least 50 wt%, at least 75 wt% or at least 95 wt% of virgin polyethylene; or said first polymeric material may comprise at least 50 wt%, at least 75 wt% or at least 95 wt% of virgin polypropylene. In embodiment A2, pellets may be produced incorporating said zeolite, said first polymeric material and said recycled polymeric material. The pellets may then be used in downstream processes, for example being optionally mixed with virgin resin and a moulded article produced therefrom. In said embodiment A2, said first mass may include 20 to 80wt% of said first polymeric material and 20 to 80wt% of recycled polymeric material. Said first mass may include 50 to 80wt% (for example 50 to 75wt%, 50 to 70wt% or 50 to 65wt%) of said first polymeric material and 20 to 50wt% (for example 25 to 50wt%, 30 to 50wt% or 35 to 50wt%) of recycled polymeric material. In an embodiment A3, said polymeric material in said first mass may include a major amount of virgin polymeric material. For example, said polymeric material in said first mass may include at least 90 wt%, at least 95 wt% or at least 99 wt% of virgin polymeric material, for example virgin polyolefin. This may advantageously be used to produce a product for use in automotive applications. A formulation comprising said zeolite Y may be used in step (ii). Said formulation may comprise at least 10wt%, preferably at least 20wt%, more preferably at least 30wt%, especially at least 40wt%, of said zeolite Y. Said formulation may include less than 90wt% or less than 80wt% of said zeolite Y. Said formulation preferably includes 10 to 80wt%, more preferably 20 to 60wt% of said zeolite Y. The sum of the wt% of all zeolites in said formulation may be at least 10wt%, preferably at least 20wt%, more preferably at least 30wt%, especially at least 40wt%. Said formulation may include less than 90wt% or less than 80wt% of zeolites in total. Said formulation preferably includes 10 to 80wt%, more preferably 20 to 60wt% of zeolites in total. The sum of the wt% of all zeolites having a Y structure in said formulation may be at least 10wt%, preferably at least 20wt%, more preferably at least 30wt%, especially at least 40wt%. Said formulation may include less than 90wt% or less than 80wt% of zeolites having a Y structure in total. Said formulation preferably includes 10 to 80wt%, more preferably 20 to 60wt% of zeolites having a Y structure in total. Said formulation may be a liquid formulation or a solid formulation, for example a solid masterbatch. Said formulation may comprise: (i) zeolite Y; and (ii) a carrier. The zeolite Y is preferably dispersed, preferably substantially homogeneously, in the carrier. Preferably, unless otherwise stated herein, the reference to “liquid” and “solid” refer to a state at 25°C and standard pressure (101325Pa). When said formulation is a liquid, the carrier is preferably a liquid. Said carrier may have a boiling point at 760mmHg in accordance with ASTM D1078 in the range 150 to 1150°C, preferably in the range 275°C to 1000°C or in the range 275°C to 500°C. Said carrier may have a viscosity measured using a Brookfield viscometer, spindle 2, 20rpm at 20°C in the range 50- 3500cP, more preferably in the range 200-1800cP. Said carrier may comprise a hydrocarbon-containing liquid. Said carrier may comprise one or more liquids, for example, one or more hydrocarbon-containing liquids. Said carrier may comprise a low molecular weight wax. Said carrier may comprise a triglyceride. Said carrier may comprise liquid rubber. Said carrier may comprise mineral oil. Examples of liquid rubbers include polyisobutylene of low MW (eg 1000 – 2500) and / or having viscosity in the range 200 – 4750 cSt; polybutadiene (MW 5000 – 10000); and ethylene-alpha- olefin co-polymer (MW 2700 – 16000). In general terms, said carrier may have a viscosity in the range 400- 50000 cps. When said carrier comprises one or more liquids, it may comprise one or more of the carriers referred to. For example, said carrier may comprise a mixture of mineral oil (eg 10 to 30wt%) and polyisobutylene and / or liquid rubber (eg 70 to 90wt%). When said formulation is a solid, said carrier may comprise a polyolefin and / or a thermoplastic elastomer (TPE). Said carrier may comprise a carrier typically used in solid masterbatches and / or which is compatible with the polymeric material in the first mass with which the formulation may be contacted. Said carrier may comprise a polyolefin, for example polyethylene (eg HDPE or LDPE) or polypropylene, a styrenic block polymer (eg styrene-ethylene-butylene-styrene (SEBS) or styrene-butadiene copolymer (SBC), ethylene-vinyl acetate (EVA) or ethylene Propylene Rubber (EPR). Said formulation, for example a liquid or solid formulation, may include 10 to 90 wt%, preferably 30 to 80wt% of said carrier. The sum of the wt% of all carriers in said formulation may be in the range 10 to 90 wt%, preferably 30 to 80wt%. In said formulation, the sum of the wt% of all zeolites and all carriers is suitably at least 50 wt%, preferably at least 70wt%, more preferably at least 90%, especially at least 95wt%. The balance may include other additives herein described. Said formulation may include a colorant which may be a pigment. Said formulation may include 0 to 50wt%, for example 0 to 10wt%, or 0 to 5wt%, of colourant(s), in total. Colorant(s) may be included to counter any discoloration in polymeric material to which the formulation may be added as described herein. Said formulation may include an antioxidant / heat stabilizer. Said formulation may include an antioxidant which may be a phenolic, phosphite, thio-ether or organic sulfide. Said formulation may include an antioxidant / free radical scavenger / anti-crosslinking agent selected from: glutathione, lipoic acid, vitamins such as ascorbic acid (vitamin C), vitamin B, vitamin D, vitamin- E, tocopherols (synthetic or natural, alpha-, gamma-, delta-), acetate vitamin esters, water soluble tocopherol derivatives, tocotrienols, water soluble tocotrienol derivatives; melatonin, carotenoids including carotenes, lutein, pycnogenol, glycosides, trehalose, polyphenols and flavonoids, quercetin, lycopene, lutein, selenium, nitric oxide, curcuminoids, 2-hydroxytetronic acid; cannabinoids, synthetic antioxidants such as tertiary butyl hydroquinone, 6-amino-3- pyrodinoles, butylated hydroxyanisole, butylated hydroxytoluene, ethoxyquin, tannins, propyl gallate, other gallates, Aquanox™ family; Irganox® and Irganox® B families including Irganox® 1010, Irganox® 1076, Irganox® 1330, Irganox® 1035; Irgafos® family; phenolic compounds with different chain lengths, and different number of OH groups; enzymes with antioxidant properties such as superoxide dismutase, herbal or plant extracts with antioxidant properties such as St. John's Wort, green tea extract, grape seed extract, rosemary, oregano extract, mixtures, derivatives, analogues or conjugated forms of these. Said formulation may include an antioxidant which is a primary antioxidant with reactive OH or NH groups such as hindered phenols or secondary aromatic amines; or secondary antioxidants such as organophosphorus compounds or thiosynergists; or multifunctional antioxidants, hydroxylamines, or carbon centered radical scavengers such as lactones or acrylated bis-phenols. Antioxidants may be selected individually or used in any combination. Antioxidants may be used in conjunction with hydroperoxide decomposers. Said formulation may include 0-10%, preferably 0-5%, more preferably 0-2wt%, of antioxidant / heat stabilizers in total. When said formulation is a liquid, said formulation may include a viscosity control agent. A viscosity control agent may be a surfactant and / or fumed silica. A viscosity control agent may be a wax, silicon dioxide, povidone, carbomer, poloxamer, carboxymethyl cellulose, hydroxyethyl cellulose or a polyacrylic acid. Said formulation may include 0 to 10wt%, 0 to 5wt% or 0 to 1wt% of viscosity control agent. In some cases, said formulation may include one or more fillers (eg inorganic fillers, such as CaCO3). Preferably, said formulation includes less than 1wt%, less than 0.5wt% or less than 0.1wt% of fillers, for example inorganic fillers. When said formulation is arranged for treatment of a mass of polymeric material for use in automotive applications, it may contain anti scratch additives, fillers and / or light stabilizers. When said formulation is a liquid formulation, it may include 40 to 75 wt% of one or more liquid carriers (preferably of a single liquid carrier), 25 to 60 wt% of zeolite Y and 0 to 5 wt% of dispersant(s). A preferred liquid formulation includes 47 to 57 wt% of one or more liquid carriers (preferably of a single liquid carrier), 40 to 50 wt% of zeolite Y and 0 to 5 wt% of dispersant(s). When said formulation is a solid formulation, it may include 40 to 75 wt% of one or more solid carriers (preferably of a single solid carrier), 25 to 60 wt% of zeolite Y and 0 to 10 wt% of dispersant(s). Preferably, said formulation is a liquid formulation. Compared to an equivalent solid formulation, a said liquid formulation may result in a smaller colour shift (dL*) of polymer into which the formulation is introduced, as illustrated in example 38. In step (ii), said first mass may be contacted with a formulation comprising said zeolite Y and / or a mixture may be produced. When a mixture is produced in step (ii) or subsequently in the method, said mixture may comprise polymeric material, carrier and said zeolite Y. Said polymeric material in said mixture may be Acrylonitrile Butadiene Styrene (ABS), Polyvinyl Butyryl (PVB), Polyvinyl Chloride (PVC), Acrylonitrile Styrene Acrylate (ASA), Polymethylmethacrylate (PMMA), polystyrene (PS) or polyolefin (PO). Preferably it is polyolefin. Said mixture may comprise polystyrene or one or more polyolefins. When said mixture comprises polystyrene, it preferably comprises at least two polystyrenes from different sources and / or which have different identities and / or properties. Said polymeric material in said mixture preferably comprises recycled material, for example PCR or PIR. Said polymeric material in said mixture may comprise 25 to 100wt%, 25 to 75wt% or 25 to 50wt%, recycled polystyrene, for example PCR. Said mixture may comprise virgin polymer, for example virgin polystyrene. Said polymeric material in said mixture preferably comprises at least 25wt% virgin polymer. Said polymeric material in said mixture may comprise 25 to 75wt% or 50 to 75wt% virgin polymer. In some cases, for example for automotive applications as aforesaid, said polymeric material in said mixture may comprise up to 100wt% of virgin polymer. Said mixture preferably comprises one or more polyolefins. It preferably comprises at least two polyolefins from different sources and / or which have different identities and / or properties. Said polymeric material in said mixture preferably comprises polyethylene. It may include 50 to 100wt% polyethylene. Said polymeric material in said mixture preferably comprises recycled material, for example PCR or PIR. It may comprise polyethylene PCR, especially HDPE PCR. Said polymeric material in said mixture preferably comprises at least 25wt% recycled material, for example PCR. Said polymeric material in said mixture may comprise 25 to 100wt%, 25 to 75wt% or 25 to 50wt%, recycled material, for example PCR. Said polymeric material in said mixture may comprise up to 50wt% of polypropylene (PP), for example 10 to 50wt% PP. Compositions of PCR may vary as between one another. For example, PCR may include inorganic contamination and / or may be contaminated with fillers. For example, said PCR may include up to 3wt%, for example 0.5 to 1wt% of inorganic contamination. Said mixture may comprise virgin polymer, for example virgin polyethylene, especially virgin HDPE. Said polymeric material in said mixture preferably comprises at least 25wt% virgin polymer. Said polymeric material in said mixture may comprise 25 to 75wt% or 50 to 75wt% virgin polymer. Said mixture may comprise a composition formed during said method; and / or may comprise a product produced in said method which may be in a solid form, for example in the form of a moulded article, pellets or granules. Said mixture may include at least 90wt%, preferably at least 94wt%, more preferably at least 96wt%, of polyolefins in total. It may include less than 99wt% or less than 98wt% of polyolefins in total. Said mixture may include at least 90wt%, preferably at least 94wt%, more preferably at least 96wt%, of polyethylene in total. It may include less than 99wt% or less than 98wt% of polyethylene in total. The balance may include said zeolite Y. Said mixture may include at least 1000 ppm zeolite Y. It may include up to 50,000 ppm of zeolite Y. Preferably, said mixture includes 1000 to 30,000 ppm, more preferably 1000 to 20,000 ppm or 5000 to 20,000 ppm of zeolite Y. Said mixture may comprise at least 0.1wt%, preferably at least 0.2wt% of said zeolite Y. Said mixture may include less than 5.0wt% or less than 2.5wt% of said zeolite Y. Said mixture preferably includes 0.1 to 5.0wt%, more preferably 0.2 to 2.5wt% of said zeolite Y. The sum of the wt% of all zeolites in said mixture may be at least 0.1wt%, preferably at least 0.2wt%. Said mixture may include less than 5.0wt% or less than 2.5wt% of zeolites in total. Said mixture preferably includes 0.1 to 5.0wt%, more preferably 0.2 to 2.5wt% of zeolites in total. The sum of the wt% of all zeolites having a Y structure in said mixture may be at least 0.1wt%, preferably at least 0.2wt%. Said mixture may include less than 5.0wt% or less than 2.5wt% of zeolites having a Y structure in total. Said mixture preferably includes 0.1 to 5.0wt%, more preferably 0.2 to 2.5wt% of zeolites having a Y structure in total. After step (ii), said method may comprise a step (iii) which comprises melt-processing the first mass and zeolite Y and / or melt-processing a mixture as described. Melt-processing may include extrusion or injection moulding the first mass and zeolite, for example to produce a moulded article, pellets, granules, sheet or film. Where pellets or granules are produced, they may subsequently be melt-processed to produce an article. In the method, said mixture may be produced after step (ii) which may be in the form of a product which may be isolated, for example from an apparatus in which it may be made. Such a product may include 50 to 99.9wt% of said first polymeric material and 0 to 49.9wt% of recycled polymeric material. Said product mass may include 50 to 79.9wt% of said first polymeric material and 20 to 49.9wt%, 25 to 49.9wt% or 30 to 49.9wt% of recycled polymeric material. The balance may include said zeolite Y. In one embodiment, polymeric material in said product may comprise up to 100wt% of recycled polymeric material, for example recycled polyolefin. The product may be in the form of granules or pellets. Alternatively, the product may be in the form of a molded article, for example produced by extrusion, such as by extrusion blow molding, compression molding or injection molding. The molded article may be a packaging article such as a receptacle or container. The molded article may be a packaging article such as a receptacle or container or a sheet. The method of the first aspect may be used prior or subsequent to use of a known process for treating recyclate to reduce malodour species, such as discussed in the introduction hereto. For example, the method of the first aspect may be used in conjunction with thermal physical processing, such as vacuum degassing or hot air / nitrogen stripping. The method of the first aspect may comprises contacting said first mass or a mixture comprising said first mass and said zeolite Y with a second adsorbent which may not be a zeolite Y and / or may be a zeolite having complementary adsorption characteristics to that of said zeolite Y. Examples of second adsorbents include aluminium oxide and hydrotalcite. In an especially preferred embodiment, said second adsorbent may be a zinc compound. For example, it may be a zinc oxide or a zinc salt, for example a zinc salt of a carboxylic acid. It is preferably a zinc carboxylate. It preferably includes a moiety (preferably at least two and more preferably only two moieties) of formula: where the O* is associated with a zinc ion and R is an optionally-substituted hydrocarbon chain, for example an optionally-substituted alkyl or alkenyl group. Group R may include 1 to 25, for example 1 to 20, carbon atoms. Group R may be unsaturated, for example in including one or more, preferably up to one, C=C moiety. When group R is optionally-substituted, it may be optionally-substituted with one or more, preferably only one, hydroxy group. Said second adsorbent may be a bis-alkanoyloxy zinc compound. Said moiety of formula (I) may be a fatty acid residue. Preferably said second adsorbent is zinc ricinoleate. When said method comprises contacting with zeolite Y and a said second adsorbent, a ratio defined as the weight percent of the zeolite Y divided by the weight percent of the second adsorbent introduced into the first mass may be in the range 0.1 to 10.0, preferably in the range 0.3 to 3:0, more preferably in the range 0.5 to 2.0. When said method uses said zeolite Y and a second adsorbent, the zeolite Y may be in one formulation as described which is used in step (ii) and said second adsorbent may be in a separate formulation which is used before, during or after step (ii). Preferably, however, said formulation used in step (ii) includes both said zeolite Y and said second adsorbent. When said method comprises contacting with zeolite Y and a said second adsorbent, the sum of the ppm of zeolite Y and a said second adsorbent relative to the weight of said polymeric material in said first mass may be referred to a “SUM XX”. SUM XX may be at least 1000 ppm. SUM XX may be up to 50,000 ppm. SUM XX may be in the range 1000 to 30,000 ppm, more preferably 1000 to 20,000 ppm or 5000 to 20,000 ppm. The sum of the wt% of zeolite Y and a said second adsorbent (said sum being referred to as “SUM YY”) in a mixture produced in step (ii) of the method may be at least 0.1wt%, preferably at least 0.2wt%. Said SUM YY may be less than 5.0wt% or less than 2.5wt%. SUMYY may be 0.1 to 5.0wt%, more preferably 0.2 to 2.5wt%. According to a second aspect of the invention, there is provided a mixture as described in the first aspect per se. Said mixture may be in the form of a product, for example a moulded article, pellets or granules which comprises polymeric material and a zeolite Y. Said zeolite Y may be as described in the first aspect. Said polymeric material preferably comprises one or more polystyrenes or one or more polyolefins. It preferably comprises at least two polyolefins from different sources and / or which have different identities and / or properties. Said polymeric material preferably comprises polyethylene. It may include 50 to 100wt% polyethylene. Said polymeric material preferably comprises recycled material, for example PCR or PIR. It may comprise polyethylene PCR, especially HDPE PCR. Said polymeric material preferably comprises at least 25wt% recycled material, for example PCR. Said polymeric material may comprise 25 to 100wt%, 25 to 75wt% or 25 to 50wt%, recycled material, for example PCR. Said polymeric material may comprise up to 50wt% of polypropylene (PP), for example 10 to 50wt% PP. Said polymeric material may comprise virgin polymer, for example virgin polyethylene, especially virgin HDPE. Said polymeric material preferably comprises at least 25wt% virgin polymer. Said polymeric material in said mixture may comprise 25 to 75wt% or 50 to 75wt% virgin polymer. Said polymeric material may include at least 90wt%, preferably at least 94wt%, more preferably at least 96wt%, of polyolefins in total. It may include less than 99wt% or less than 98wt% of polyolefins in total. Said polymeric material may include at least 90wt%, preferably at least 94wt%, more preferably at least 96wt%, of polyethylene in total. It may include less than 99wt% or less than 98wt% of polyethylene in total. Said mixture may comprise at least 0.1wt%, preferably at least 0.2wt% of said zeolite Y. Said mixture may include less than 5.0wt% or less than 2.5wt% of said zeolite Y. Said mixture preferably includes 0.1 to 5.0wt%, more preferably 0.2 to 2.5wt% of said zeolite Y. The sum of the wt% of all zeolites in said mixture may be at least 0.1wt%, preferably at least 0.2wt%. Said mixture may include less than 5.0wt% or less than 2.5wt% of zeolites in total. Said mixture preferably includes 0.1 to 5.0wt%, more preferably 0.2 to 2.5wt% of zeolites in total. The sum of the wt% of all zeolites having a Y structure in said mixture may be at least 0.1wt%, preferably at least 0.2wt%. Said mixture may include less than 5.0wt% or less than 2.5wt% of zeolites having a Y structure in total. Said mixture preferably includes 0.1 to 5.0wt%, more preferably 0.2 to 2.5wt% of zeolites having a Y structure in total. Said mixture may include zeolite Y and a second adsorbent, wherein said zeolite Y and said second adsorbent independently have any feature of the zeolite Y and said second adsorbent as described in the first aspect. When said mixture comprises zeolite Y and a said second adsorbent, the sum of the ppm of zeolite Y and a said second adsorbent relative to the weight of polymeric material in said mixture may be referred to a “SUM XX”. SUM XX may be at least 1000 ppm. SUM XX may be up to 50,000 ppm. SUM XX may be in the range 1000 to 30,000 ppm, more preferably 1000 to 20,000 ppm or 5000 to 20,000 ppm. The sum of the wt% of zeolite Y and a said second adsorbent (said sum being referred to as “SUM YY”) in said mixture may be at least 0.1wt%, preferably at least 0.2wt%. Said SUM YY may be less than 5.0wt% or less than 2.5wt%. SUMYY may be 0.1 to 5.0wt%, more preferably 0.2 to 2.5wt%. According to a third aspect of the invention, there is provided a formulation as described in the first aspect per se. Said formulation may be a liquid formulation or a solid formulation, for example a solid masterbatch. Said formulation may comprise: (i) zeolite Y; and (ii) a carrier. Said formulation may comprise at least 10wt%, preferably at least 20wt%, more preferably at least 30wt%, especially at least 40wt%, of said zeolite Y. Said formulation may include less than 90wt% or less than 80wt% of said zeolite Y. Said formulation preferably includes 10 to 80wt%, more preferably 20 to 60wt% of said zeolite Y. The sum of the wt% of all zeolites in said formulation may be at least 10wt%, preferably at least 20wt%, more preferably at least 30wt%, especially at least 40wt%. Said formulation may include less than 90wt% or less than 80wt% of zeolites in total. Said formulation preferably includes 10 to 80wt%, more preferably 20 to 60wt% of zeolites in total. The sum of the wt% of all zeolites having a Y structure in said formulation may be at least 10wt%, preferably at least 20wt%, more preferably at least 30wt%, especially at least 40wt%. Said formulation may include less than 90wt% or less than 80wt% of zeolites having a Y structure in total. Said formulation preferably includes 10 to 80wt%, more preferably 20 to 60wt% of zeolites having a Y structure in total. The zeolite Y is preferably dispersed, preferably substantially homogeneously, in the carrier. When said formulation is a liquid, the carrier is preferably a liquid. Said carrier may have a boiling point at 760mmHg in accordance with ASTM D1078 in the range 150 to 1150°C, preferably in the range 275°C to 1000°C or in the range 275°C to 500°C. Said carrier may have a viscosity measured using a Brookfield viscometer, spindle 2, 20rpm at 20°C in the range 50- 3500cP, more preferably in the range 200-1800cP. Said carrier may comprise a hydrocarbon-containing liquid. Said carrier may comprise one or more liquids, for example, one or more hydrocarbon-containing liquids. Said carrier may comprise a low molecular weight wax. Said carrier may comprise a triglyceride. Said carrier may comprise liquid rubber. Said carrier may comprise mineral oil. Examples of liquid rubbers include polyisobutylene of low MW (eg 1000 – 2500) and / or having viscosity in the range 200 – 4750 cSt; polybutadiene (MW 5000 – 10000); and ethylene-alpha- olefin co-polymer (MW 2700 – 16000). In general terms, said carrier may have a viscosity in the range 400- 50000 cps. When said carrier comprises one or more liquids, it may comprise one or more of the carriers referred to. For example, said carrier may comprise a mixture of mineral oil (eg 10 to 30wt%) and polyisobutylene and / or liquid rubber (eg 70 to 90wt%). When said formulation is a solid, said carrier may comprise a polyolefin and / or a thermoplastic elastomer (TPE). Said carrier may comprise a carrier typically used in solid masterbatches. Said carrier may comprise a polyolefin, for example polyethylene (eg HDPE or LDPE) or polypropylene, a styrenic block polymer (eg styrene-ethylene-butylene-styrene (SEBS) or styrene-butadiene copolymer (SBC), ethylene-vinyl acetate (EVA) or ethylene Propylene Rubber (EPR). Said formulation may include 10 to 90 wt%, preferably 30 to 80wt% of said carrier. The sum of the wt% of all carriers in said formulation may be in the range 10 to 90 wt%, preferably 30 to 80wt%. In said formulation, the sum of the wt% of all zeolites and all carriers is suitably at least 50 wt%, preferably at least 70wt%, more preferably at least 90%, especially at least 95wt%. The balance may include other additives herein described. Said formulation may include a colorant which may be a pigment. Said formulation may include 0 to 50wt%, for example 0 to 10wt%, or 0 to 5wt%, of colourant(s), in total. Colorant(s) may be included to counter any discoloration in polymeric material to which the formulation may be added as described herein. Said formulation may include an antioxidant / heat stabilizer, for example as described in the first aspect. Said formulation may include 0-10%, preferably 0-5%, more preferably 0-2wt%, of antioxidant / heat stabilizers in total. When said formulation is a liquid, said formulation may include a viscosity control agent. A viscosity control agent may be a surfactant and / or fumed silica. A viscosity control agent may be a wax, silicon dioxide, povidone, carbomer, poloxamer, carboxymethyl cellulose, hydroxyethyl cellulose or a polyacrylic acid. Said formulation may include 0 to 10wt%, 0 to 5wt% or 0 to 3wt% of viscosity control agent. In some cases, said formulation may include one or more fillers (eg inorganic fillers, such as CaCO3). Preferably, said formulation includes less than 1wt%, less than 0.5wt% or less than 0.1wt% of fillers, for example inorganic fillers. In some cases, said formulation may include both zeolite Y and a second adsorbent as described in the first or second aspects. In this case, in said formulation, a ratio defined as the weight percent of the zeolite Y divided by the weight percent of the second adsorbent introduced may be in the range 0.1 to 10.0, preferably in the range 0.3 to 3:0, more preferably in the range 0.5 to 2.0. When said formulation includes both zeolite Y and a second adsorbent, the sum of the wt% of zeolite Y and said second adsorbent in said formulation may be referred to as “SUM QQ”, In said formulation, SUM QQ may be at least 10wt%, preferably at least 20wt%, more preferably at least 30wt%, especially at least 40wt%. In said formulation, SUM QQ may be less than 90wt% or less than 80wt%. SUM QQ may be 10 to 80wt%, more preferably 20 to 60wt%. In a preferred embodiment, when said formulation includes both zeolite Y and a second adsorbent, said second adsorbent may be a zinc compound as described in the first aspect. Said second adsorbent may be a bis-alkanoyloxy zinc compound. Preferably said second adsorbent is zinc ricinoleate. Any feature of any aspect of any invention described herein may be combined with any feature of any other invention described herein mutatis mutandis. Specific embodiments of the invention will now be described, by way of example, with reference to the accompanying figures, in which: Figure 1 details the % reduction in the levels of specified species for Comparative Examples C1 to C11; Figure 2 details the % reduction in the levels of specified species for Examples 7 to 11 and C14 to C16; Figure 3 details the % reduction in the levels of specified species for Examples 14 to 20; and Figure 4 is a graph of change in lightness / darkness (dL*) v. concentration of Zeolite Q1 for a liquid dispersion and solid masterbatches. The following materials are referred to herein. Versalis Eraclene BC 82 – refers to a high-density polyethylene resin (HDPE). Spiked HDPE resin – refers to an HDPE resin, spiked with a mixture of odour species having different classes of chemical functional groups present (eg acids, aldehydes and / or ketones) which are commonly found in commercial grades of PCR. The resin is prepared by extruding a base virgin HDPE resin (Versalis Eraclene BC 82) with addition of a mixture comprising hexanal, octanal, 1-hexanol, 2-hexanone, dodecane, methylhexanoate, ethylene glycol butyl ether, hexanoic acid, nonanoic acid, limonene, linalool and eugenol. Real world PCR – refers to commercially-available HDPE recycle grades currently in use in the European market. PCR grades can vary greatly in terms of melt flow index, polypropylene content and inorganic content. The table below shows a typical range of these PCR properties: Melt flow Index (190°C, g / 10min) 0.2-5 PE Content 45-100% PP content 0-55% Inorganic content 0-15% When real world PCR is used in any example herein, it is blended with Versalis Eraclene BC 82 at a 1:1 weight ratio. This is higher in terms of the weight of PCR than is currently used commercially – usually about 25wt% PCR is blended with virgin resin due to the malodour of the real world PCR in the absence of satisfactory adsorbents. The following are sold as general adsorbents. Material CAS Number Form Hydrotalcite 11097-59-9 Powder Bentonite 1302-78-9 Powder Sepiolite 63800-37-3 Powder Kaolinite 1318-74-7 Powder Talc 14807-96-6 Powder Zeolite P1 1318-02-1 Powder Zeolite P2 1318-02-1 Powder Zeolite P3 1318-02-1 Powder Zeolite P4 1318-02-1 Powder SG-60A 7631-86-9 Powder (Silica gel 60Å pore size) The following are referred to herein: Zeolite reference Zeolite Q1 Zeolite P5 CAS 1318-02-1 1318-02-1 Zeolite Class Y ZSM-5 Form Powder Powder Active % 97.2 99.9 SiO2 / Al2O3 mole ratio 5.1:1 30:1 Counter ion Hydrogen Hydrogen Surface area (m2 / g) 730 400 The following other materials are referred to herein: Surface Si:Al Counter area Zeolite Sample ID ratio Structure Ion (m2 / g) Zeolite Q2 5.2:1 Y Ammonium 750 Zeolite Q3 30:1 Y Hydrogen 780 Zeolite Q4 60:1 Y Hydrogen 720 Zeolite Q5 80:1 Y Hydrogen 780 Zeolite P6 13:1 Mordenite Sodium 425 Zeolite P7 20:1 Mordenite Ammonium 500 Zeolite P8 38:1 Beta Ammonium 710 Zeolite P9 30:1 ZSM-5 Ammonium 400 Zeolite P10 50:1 ZSM-5 Ammonium 425 Zeolite P11 80:1 ZSM-5 Ammonium 425 Zeolite P12 200-400:1 ZSM Ammonium 400 Unless otherwise stated, a reference to “ppm” is to the “parts per million” by weight of one material contained in a mass of another material. The following Assessments are referred to herein: Assessment #1 – Evaluation of volatile emissions from resins Unless otherwise stated herein, a standard analytical test protocol using thermal desorption gas chromatography (TD-GC-MS) was used to evaluate volatile emissions from spiked odour resins and real world PCRs. This was used to understand the global and specific emissions of a material and also be used to demonstrate effectiveness of a solution. The key parameters for TD-GC-MS analytical method are shown below: TD conditions: Instrument: Markes International TD100-xr™ Desorption temp.: 110°C; Desorption time: 30 min Focusing trap: Air Toxins, (Markes International part no. U-T3ATX-2S) Focusing trap temp.: –30°C Trap desorption temperature: 290°C Focusing trap desorb time: 5 min; GC conditions: Instrument: Thermofisher Scientific Trace 1310 GC Column : Thermofisher Scientific TG-5MS, 60 m × 0.25 mm × 0.25 μm Carrier: Helium Carrier gas flow: 1.5 mL / min (constant flow) Oven program: 80°C (5 min), 3°C / min to 250°C, hold time 10 min Quadrupole MS conditions: Instrument: Thermofisher Scientific TSQ 9000-AEI Transfer line: 250°C Ion source: 250°C Mass range: m / z 45–300 Scan time: 0.2 s Assessment #2 - Evaluation of odour intensity of resins The odour intensity of selected resins was assessed using a method based on VDA 270 relating to the determination of the odour characteristics of trim materials in motor vehicles. In the assessment, a sensory panel of four participants assessed the odour intensity of each sample and applied a rating according to the odour intensity scale below. Odour Intensity Rating Description 6 Extremely strong 5 Very strong 4 Strong 3 Distinct 2 Weak 1 Very weak 0 Not perceptible Samples were prepared for assessment by weighing 40g of pellets into 180ml containers and a lid placed on each container. Containers were kept at room temperature. Each participant removed the lid, assessed the odour in the headspace of the jar and assigned a rating. In the results, an average intensity rating is reported. Example 1 – General procedure for preparing liquid formulations of candidate odour-reducing materials Liquid formulations were produced as dispersions by mixing a candidate odour-reducing material with a liquid carrier, optionally in the presence of a dispersant. The material may be progressively added and mixed with the carrier and optional dispersant, using a high speed disperser, at 1000 – 3000 rpm for 1 min, followed by a final mix for at least 5 minutes at 3000rpm. Liquid formulations may include up to 50wt% of candidate odour-reducing materials, up to 5wt% of dispersant, with the balance being a liquid carrier. The carrier suitably has good solubility in the polymer into which it is added. It may be selected from: CAS 8042-47-5 white mineral oils, CAS 64741-89-5 distillates petroleum, CAS 64742-47-8 distillates hydrotreated, CAS 9005-70- 3 ethoxy sorbitan trioleate, CAS 26266-58-0 sorbitan trioleate, CAS 68956-68-3 canola oil Dispersants may be selected from: a polymeric hyper dispersant including polymeric hyperdispersants with amine anchor and polymeric hyperdispersants with acid anchor. Example 2 - General for preparing solid formulations of candidate odour- materials Solid formulations in the form of masterbatches may be prepared by extruding mixtures of solid carrier, candidate odour-reducing material and optional dispersant, followed by pelletization. Solid formulations may include up to 50wt% of candidate odour-reducing materials, up to 5wt% of dispersant, with the balance being a carrier resin. Carrier resin may be selected from LDPE, HDPE, for example Versalis Eraclene BC 82, or similar carrier resin. A dispersant may be a polyethylene wax. Example 3 – General procedure for producing pellets comprising spiked odour resins or real world PCRs and formulations of odour-reducing materials via feed-throat addition (1stmethod) Resin pellets are weighed into a container and either raw candidate odour-reducing material or a liquid dispersion of a candidate odour-reducing material, as described in Example 1, is weighed onto the pellets at a predetermined dosing wt%. The container is sealed and shaken in a vibrating mixer to ensure homogeneity. The mixture is then poured into an extruder hopper and fed into an extruder feed throat of a Rondol twin screw extruder at a set rate. Pellets comprising spiked odour resins or real world PCRs and formulations of odour-reducing materials are produced for subsequent assessment. The same process can be used with solid formulations of Example 2. Suitably, in a preferred embodiment, the Example 1 formulation is used with 45wt% loading of odour-reducing material. This is found to disperse well in the resin and have negligible impact thereon. Example 4 – General procedure for producing pellets comprising spiked odour resins or real world PCRs and formulations of odour-reducing materials via melt injection (2nd method) This involves injection of a liquid dispersion of a candidate odour-reducing material, as described in Example 1, via a port along the extruder barrel of a Khune single screw extruder (38mm) such that it mixes directly with the molten resin inside the screw. It is then processed through a strand die and pelletiser to produce pellets. to assess effectiveness in levels of odour Pellets were analysed by TD-GC-MS as per Assessment #1 to separate and quantify the concentration of odour species present in pellets. In reporting results, quantities of odour species in pellets containing candidate odour reducing material are compared to appropriate controls which comprise the same resin except that any candidate odour reducing material being assessed is omitted. The % reduction of odour species present can then be calculated compared to the control. In addition, to aid comparisons, the sum of all terpinene related species was determined as “total terpinene” and referred to herein as “TTC reduction”. This recognises that some candidate odour reducing materials may isomerise odour species which would not reduce the overall concentration. Example 6 – Effectiveness of candidate odour-reducing materials. Following the procedure described in Example 5, the odour-reducing performance of a range of adsorbents were assessed, when incorporated into spiked HDPE using a liquid formulation as described in Examples 3. The table below details the identity and ppm of the adsorbents in HDPE pellets produced. Example No. Identity of adsorbent ppm of adsorbent in HDPE C1 Bentonite 2000 C2 Kaolinite 2000 C3 Kaolinite 5000 C4 Sepiolite 2000 C5 Sepiolite 5000 C6Zeolite P42000C7Zeolite P45000C8Zeolite P15000C9Zeolite P32000C10 Talc 3000 C11 Hydrotalcite 3000 Figure 1 details the % reduction in the levels of specified species. In Figure 1, for some of examples C1 to C11, there was no measured reduction in the levels of certain specified species. Figure 1 shows, in general terms, that the known adsorbents offer only a limited benefit, even at relatively high addition levels. Examples 7 to 11 and C14 to C16 – Comparison of a preferred odour-reducing material with candidate adsorbents Following the procedure described in Example 5, the odour-reducing performance of Zeolite Q1 (previously determined to be an advantageous odour-reducing material) was assessed against a number of known adsorbents, incorporated into spiked HDPE as described in Example 3. The table below details the identity and ppm of the adsorbents in HDPE pellets produced as described in Example 5. Example No. Identity of adsorbent ppm of adsorbent in HDPE 7 Zeolite Q1 50 8 Zeolite Q1 100 9 Zeolite Q1 250 10 Zeolite Q1 500 11 Zeolite Q1 1000 C14 Zeolite P2 2000 C15 Zeolite P2 5000 C16 Zeolite P5 1000 Figure 2 details the % reduction in the levels of specified species (limonene reduction, eugenol reduction, linalool reduction and TTC reduction) and illustrates that Zeolite Q1 has high efficacy, at relatively low concentration, resulting in significant reduction in levels of key odour species. In the figure, the total terpinene concentration does not reduce for Zeolite P2 and Zeolite P5 but there are reductions in limonene, eugenol and linalool. This suggests that, when Zeolite P2 is used, limonene, eugenol and linalool are converted into other turpinenes which still have an odour response, whereas with Zeolite Q1, the same odour species are either removed or further converted into species with no odour response (ie not turpinenes). This may demonstrate that Zeolite Q1 is acting to convert certain odour species to species which have lower (or no) odour response or remove them entirely from the polymer matrix. Example 12 and Comparative Examples C17-C20 – Assessment of performance of Zeolite Q1 compared to other candidate adsorbents against wide range of odour species Following the procedure described in Example 5, the odour-reducing performance of a range of known adsorbents, incorporated into spiked HDPE as described in Examples 3 was assessed. The odour species assessed and the results, at specified addition levels (ppm relative to the spiked HDPE resin), for Zeolite Q1 and other adsorbents (Zeolite P4, Kaolinite, masterbatch comprised of a mixture of zinc ricinoleate and other adsorbents and bentonite) are detailed in the table below. Example Candidate Additive Limonen 2-Hexanone % Hexanal 1- Ethylene Methyl- Hexanoic Octanal Linalool % Nonanoic Eugenol % No. adsorbent ppm e % % Hexanol glycol butyl hexanoate acid % % acid % % ether % % C14Zeolite5000 3.26 10.01 4.14 31.16 90.44 7.06 82.00 9.32 -1.78 36.15 49.47 P4 C15Kalonite5000 -15.34 19.27 - 17.39 -25.22 -45.66 -8.96 -49.19 -7.69 -100.00 -15.83 -14.78 C16Masterba 10000 12.29 33.17 27.88 29.73 28.11 25.52 -90.91 24.23 23.69 -99.47 -2.51 tch comprise d of a mixture of zinc ricinoleat e and other adsorben ts C17Bentonite5000 -24.84 -26.32 -3.33 -9.27 -86.75 -6.90 -87.52 -9.56 -100.00 -75.58 -58.74 12 Zeolite 5000 -100.0 -90.50 -95.61 -97.01 -99.89 -90.99 -100.00 -92.22 -86.32 -28.19 -92.78 Q1

[0002] Example 13 and Comparative Examples C21 to C23 – Odour-reduction in real world PCR A very wide range of odour species are found in commercially available HDPE PCR including a wide range of organic, inorganic and polymeric contamination. Following the procedure described in Example 5, the odour reducing performance of a range of candidate adsorbents was assessed (each included at 5000ppm in HDPE PCR) for their ability to reduce levels of a wide range of odour species and / or contaminants and results are provided in the table below. The table details the % reductions, with the more negative the value, the greater the extent of reduction. Where the % reduction is shown as positive for a particular specie, the implication is that there has been a conversion of one or more other species into the particular specie. Concentrations were determined by semi-quantification with 2-methylheptane.

[0003] Example 13 Example C22 % Example C21 % Example C23 % Concentration of odour cie assessed % re reduction Identity of odour spe duction reduction achieved reduction achieved specie in control (ppm) achieved using achieved using using Zeolite P5 using Zeolite P1 Zeolite Q1 Zeolite P2 D-Limonene 3.33 -100.00% 45.63% 5.34% 13.45% 3-Dodecene, (E)- 6.59 -16.49% -19.51% -3.91% -17.91% Dodecane 3.19 -1.97% -8.38% -2.42% -6.14% Isobornyl acetate 3.38 -96.61% -60.58% -1.75% 4.45% ortho tert-Butyl cyclohexyl acetate 6.18 -100.00% -6.09% -5.70% -1.54% 4-tert-Butylcyclohexyl acetate 5.09 -100.00% 9.77% 11.00% 14.19% 1-Hexadecanol 14.57 -23.17% -19.49% 7.57% -10.70% Tetradecane 12.90 -6.42% -5.42% 0.46% -5.55% Diphenyl ether 2.81 -20.26% 0.76% 0.39% 3.18% Indan-1,3-diol monoacetate 5.55 -100.00% -0.27% 4.77% 3.74% (3S,6S)-6-Isopropyl-3-methyl-2-(propan-2- 2.70 -57.10% -17.32% -20.61% -29.50% ylidene)-3-vinylcyclohexanone

[0004] Hexadecane 2.98 0.39% -0.81% -3.00% -12.31% 2,4-Di-tert-butylphenol 2.26 -20.60% 17.43% 1.03% -1.18% (3aR,4S,7S,7aS)-3a,4,5,6,7,7a-Hexahydro- 3.47 -79.11% 4.60% 1.25% 3.44% 1H-4,7-methanoinden-6-yl propionate Isoamyl salicylate 3.02 -100.00% 5.15% -0.33% -0.61% Benzoic acid, 2-hydroxy-, pentyl ester 3.42 -79.11% 2.85% 0.57% -3.03% 1-Hexadecanol 25.29 -16.51% -12.85% 5.62% -10.27% Diethyl Phthalate 50.43 0.99% 26.61% 0.23% -10.16%,2,4-Trimethyl-1,3-pentanediol diisobutyrate 7.15 4.33% 36.38% -4.52% -38.61% Cyclopentaneacetic acid, 3-oxo-2-pentyl-, 2.51 -79.37% 2.32% -6.63% -7.14% methyl ester Amberonne (isomer 2) 6.42 -46.94% 3.46% 4.06% 3.65% n-Hexyl salicylate 4.97 -100.00% 5.35% 2.25% -0.78% Heptadecane 3.02 -12.16% -1.53% -2.35% -7.57% Amberonne (isomer 3) 2.59 -100.00% 5.33% -3.35% -0.51% Octanal, 2-(phenylmethylene)- 9.48 -100.00% 8.91% 1.57% 1.25% 1-Nonadecene 26.97 -12.25% -11.23% 3.06% -15.53%

[0005] Eicosane 12.60 8.70% -1.36% -1.70% -10.18% Isopropyl myristate 4.99 -57.51% -3.38% 8.04% -14.47% Cyclopenta[g]-2-benzopyran, 1,3,4,6,7,8- 4.23 -20.80% 8.75% 1.21% -9.79% hexahydro-4,6,6,7,8,8-hexamethyl- 7-Acetyl-6-ethyl-1,1,4,4-tetramethyltetralin 3.54 -10.88% 14.36% 3.91% -0.55% Carbonic acid, ethyl octadecyl ester 7.33 -100.00% -80.82% -46.80% 40.90% Benzoic acid, 2-hydroxy-, phenylmethyl ester 6.24 -100.00% 24.51% 13.52% -15.11% 7,9-Di-tert-butyl-1-oxaspiro(4,5)deca-6,9- 2.32 -100.00% -71.31% -28.73% 10.25% diene-2,8-dione 1-Docosene 15.65 -12.73% -10.96% -1.57% -19.17% Heneicosane 4.68 1.00% -0.77% -6.55% -14.02% Isopropyl palmitate 3.66 -49.65% -18.34% -19.93% -13.54% 1-Eicosanol 1.07 -100.00% -100.00% -37.36% 199.74% Nonacos-1-ene 5.68 -10.38% -8.87% -3.73% -19.23%

[0006] It should be noted from the above table that Example 13 provides outstanding performance compared to the comparative examples. Examples 14 to 20 – Assessment of performance of Zeolite Q1 in combination with other known adsorbents The procedure described in Example 5 was followed to assess the odour-reducing performance of combinations of Zeolite Q1 and other adsorbents (referred to as a “second adsorbent”). The table below details the identity and ppms of each second adsorbent which was introduced into spiked HDPE along with 1000 ppm of Zeolite Q1. The latter was added as described in Example 3, with the second adsorbent being added with the Zeolite Q1 as a dry powder. Example No. Identify of second Adsorbent Ppm of second adsorbent in HDPE 14 Sepiolite 2000 15 Kaolinite 2000 16 SG-60A 2000 17Zeolite P2200018Zeolite P3200019 Evonik Aerosil®200 hydrophilic fumed 2000 silica 20 Evonik Aerosil®R972 hydrophobic 2000 fumed silica Results are provided in Figure 3 which shows outstanding performance of the combinations. It appears that the second adsorbents are complementary and / or synergistic with the Zeolite Q1. Examples 21 to 24 – Assessments of performance of Zeolite Q1 in combination with other known adsorbents in real world PCR Following the procedure described for Examples 14 to 20, the performance of Zeolite Q1 (at two different levels) in combination with adsorbents aluminium oxide or hydrotalcite were assessed in real world PCR. Results are provided in the table below which in each case details the % reductions, with the more negative the value, the greater the extent of reduction. Where the % reduction is shown as positive for a particular specie, the implication is that there has been a conversion of one or more other species into the particular specie. Example 21 Example 22 Example 23 Example 24 Concentration Identity of odour Zeolite Q1 Zeolite Q1 Zeolite Q1 Zeolite Q1 in Control specie assessed (5000ppm) / Aluminium (10000ppm) / Aluminium (5000ppm) / Hydrotalcite (10000ppm) / Hydrotalcite (ppm)* oxide(5000ppm) (% oxide(5000ppm) (% (5000ppm) (% (5000ppm) (% reduction) reduction) reduction) reduction) D-Limonene 6.86 -48.63% -100.00% -70.55% -100.00% 3-Dodecene, (E)- 6.42 2.93% -52.29% -19.16% -49.60% Dodecane 3.45 2.15% 1.55% -3.36% -1.32% Isobornyl acetate 4.15 -97.37% -100.00% -95.33% -100.00% ortho tert-Butyl 5.34 -46.35% -72.23% -58.78% -63.68% cyclohexyl acetate 1-Tetradecene 14.57 -10.56% -62.25% -23.49% -63.74% Tetradecane 15.51 -0.58% -9.57% -6.73% -10.42% Diphenyl ether 6.80 -3.23% -38.31% -9.76% -39.34% Pentadecane 3.99 -8.13% -17.93% -9.39% -19.27% Butylated 2.15 5.60% -15.93% 1.93% -2.73% Hydroxytoluene

[0007] Benzoic acid, 2- hydroxy-, 2- 2.77 -60.02% -83.59% -66.13% -84.19% methylbutyl ester Benzoic acid, 2- hydroxy-, pentyl 5.13 -71.85% -89.99% -67.37% -95.50% ester 1-Hexadecanol 23.87 -10.58% -57.93% -20.16% -61.82% Diethyl Phthalate 63.19 -12.27% -20.64% -16.73% -29.48% 2,2,4-Trimethyl- 1,3-pentanediol 4.99 31.47% -8.14% 15.25% 1.11% diisobutyrate Octane, 1,1'- 2.91 -18.18% -67.12% -9.72% -53.79% oxybis- Amberonne 4.63 -40.44% -89.37% -55.40% -92.34% n-Hexyl salicylate 12.64 -62.30% -90.37% -55.71% -83.11% Nonadecane 3.29 -12.66% -19.02% -11.44% -19.05% Benzene, (1- 2.41 -8.33% -31.72% -19.27% -29.95% methyldecyl)-

[0008] Octanal, 2- 7.86 -64.49% -100.00% -76.78% -100.00% (phenylmethylene)- 1-Nonadecene 26.78 -16.37% -52.57% -20.40% -59.54% Heneicosane 16.00 -11.67% -9.73% -10.40% -11.84% Isopropyl myristate 4.60 -49.32% -90.36% -60.24% -90.85% Benzoic acid, 2- hydroxy-, 3.79 -92.79% -100.00% -89.91% -100.00% phenylmethyl ester Hexadecanoic 2.51 -32.85% -62.39% -21.58% -71.39% acid, methyl ester 1-Heneicosanol 17.08 -21.98% -45.45% -26.03% -57.81% Eicosane 7.02 -18.10% -9.85% -18.55% -23.01% Isopropyl palmitate 3.72 -49.93% -86.38% -62.25% -89.37% Nonacos-1-ene 6.39 -20.93% -37.87% -26.14% -57.32%

[0009] The results in general show exceptional performance of the examples in significantly reducing the levels of a wide range of colour species in real world PCR. Examples 25 to 31 and C24 to C40 -Analysis of performance of a range of zeolite materials at reducing key odour species. A HDPE polymer was spiked with approximate concentrations of key odour species as detailed in the table below: Limon 2- Hexa 1- Ethyl Methyl Hexanoic Octa Linal Dodec Nonan Euge Total ene Hexan nal Hexa ene hexan acid nal ool ane oic nol one nol glycol oate acid butyl ether (ppm) (ppm) (ppm) (ppm) (ppm) (ppm) (ppm) (ppm (ppm) (ppm) (ppm) (ppm) (ppm ) ) 18.005 10.250 9.508 10.42 14.75 13.910 10.592 13.34 14.60 18.270 18.149 20.97 172.7 1 7 6 9 3 89 The procedure described in example 5 was followed to assess odour reducing performance of a range of candidate odour reducing materials comprising zeolites and other materials which were added at specified loadings in liquid formulations or as dry powders. The table below provides information on materials assessed and results obtained, including the percentage reductions obtained with each of the additives. Reduction v. Example No Candidate odour Loading baseline reducing material (ppm) (%) 25Zeolite Q1 1000 -53% 26Zeolite Q1 2500 -67% 27Zeolite Q2 1000 -53%28Zeolite Q2 2500 -76%29Zeolite Q3 2500 -62%30Zeolite Q4 2500 -62%31Zeolite Q5 2500 -65%C24Zeolite P6 1000 -3%C25Zeolite P6 2500 -25%C26Zeolite P7 1000 -14%C27Zeolite P7 2500 -28%C28Zeolite P8 1000 -33%C29Zeolite P8 2500 -45%C30Zeolite P9 1000 -26%C31Zeolite P9 2500 -25%C32Zeolite P10 1000 -16%C33Zeolite P10 2500 -42%C34Zeolite P11 1000 -18%C35Zeolite P11 2500 -25%C36Zeolite P12 1000 -26%C37Zeolite P12 2500 -30%C38Sepiolite 2000 -28%C39Bentonite 2000 -13%C40 Zeolite P1 2000 10% The results show the Examples 25 to 31 materials (which are all Y zeolites) are more effective at reducing the levels of odour species compared to the other candidate odour reducing materials. Examples 32 to 37 – Odour reduction in real world “problem” PCR. Some commercially available grades of PCR (referred to as PCR1 and PCR2) were found to be “problematic” in that odour reduction using a single odour-reducing material was less than optimum. Such PCR was treated with Zeolite Q1 and zinc ricinoleate in a 1:1 weight ratio, as described below. The PCR may be treated with Zeolite Q1 as described for Example 3. Zinc ricinoleate was added as a dry powder as described for Examples 14 to 20. Treated samples were assessed as described in Assessment #2 and compared to other examples as detailed in the table below. Example No Detail on Active concentration Average odour composition (ppm) intensity rating assessed (the total ppm of the additive(s)) 32 PCR1 reference 0 4 (Comparative) 33 PCR1 + Zeolite 7500 4 Q1 34 PCR1 + 50:50 10000 2 Zeolite Q1 / Zinc ricinoleate 35 PCR2 reference 0 5 (Comparative) 36 PCR2 + Zeolite 5000 3.5 Q1 37 PCR2 + 50:50 5000 1.5 Zeolite Q1 / Zinc ricinoleate It will be noted from the above table that addition of zinc ricinoleate significantly improves (ie reduces) the intensity ratings (see Examples 34 and 37 and compare to the other examples). The rating achieved is found to be acceptable for automotive trim applications (which require an intensity rating ≤2.5). Example 38 - Comparison between liquid dispersion comprising adsorbent and solid masterbatch comprising adsorbent. Following the general procedure described in Example 2, a solid masterbatch containing Zeolite Q1 was prepared by extrusion with a LDPE polymer carrier to produce a masterbatch with active loading of 45wt%. Following the general procedure described in Example 1, liquid formulations were prepared comprising Zeolite Q1 with active loading of 45wt%. Plaque samples were produced by injection moulding Eraclene HDPE virgin polymer with addition of liquid formulations to produce three active levels of 1000, 2500 and 5000ppm. Comparative plaque samples were produced by injection moulding Eraclene HDPE virgin polymer with addition of the masterbatch to produce three active levels of 1000, 2500 and 5000ppm. Plaque colour was measured using a Minolta CM-3600-A spectrophotometer and results are provided in Figure 4. These clearly show that the colour shift when using masterbatch comprising adsorbent is significantly greater (and therefore disadvantageous) than when the adsorbent is added using a liquid formulation. Example 39 - Identifying specific zeolites in polymer compositions In some situations, it may be desirable to be able to identify the presence and / or identity of zeolites in polymer compositions. This may be undertaken as follows: Polymer pellets (or any available form of polymer containing suspected zeolite) is ashed for about 1 hour at 550 °C in a large crucible. Then a Rigaku Miniflex™ can be used to collect diffraction patterns of the zeolite and ash samples from 2θ = 3 to 90°. The 1-D integrated diffraction patterns are peak fitted and compared to a database of diffraction patterns in the manufacturer supplied software to identify any zeolite present. The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

CLAIMS 1 A method of treating a mass of polymeric material, the method comprising: (i) selecting a first mass comprising a polymeric material; and (ii) contacting said first mass with a zeolite Y. 2 A method according to claim 1, wherein said zeolite Y has a Si:AI molar ratio of at least 3.0 (preferably at least 5.0); and / or said molar ratio is in the range 5.0:1 to 100:

1. 3 A method according to claim 1 or claim 2, wherein said zeolite Y has a counterion selected from H+, Na+and NH4+. 4 A method according to any preceding claim, wherein said zeolite Y has a surface area of at least 410 m2 / g (preferably at least 700 m2 / g). 5 A method according to any preceding claim, being a method of treating a mass of polymeric material to reduce the odour of the mass. 6 A method according to any preceding claim, wherein said method comprises treating a first mass which comprises recycled polymeric material. 7 A method according to claim 6, wherein said recycled polymeric material is recycled polystyrene or recycled polyolefin. 8 A method according to any preceding claim, wherein said first mass includes at least 90 wt% (or at least 99 wt%) of recycled polymeric material, for example recycled polyolefin. 9 A method according to any of claims 6 to 8, wherein said recycled polymeric material comprises at least 90% (preferably at least 99 wt%) polyethylene or at least 90 wt% (preferably at least 99 wt% of polypropylene). 10 A method according to any preceding claim, wherein pellets are produced incorporating said zeolite. 11 A method according to any preceding claim, wherein said first mass comprises a first polymeric material and recycled polymeric material, wherein said first polymeric material comprise at least 80 wt% of virgin polystyrene or virgin polyolefin and said first mass includes 20 to 80wt% of said first polymeric material and 20 to 80wt% of recycled polymeric material.12 A method according to any preceding claim, wherein a formulation comprising said zeolite Y is used in step (ii), wherein said formulation includes 10 to 80wt% (preferably 20 to 60wt%) of said zeolite Y. 13 A method according to claim 12, wherein said formulation includes 10 to 80wt% (preferably 20 to 60wt%) of zeolites in total; and / or the sum of the wt% of all zeolites having a Y structure in said formulation is at least 10wt% and less than 80wt%. 14 A method according to claim 12 or claim 13, wherein said formulation comprises: (i) zeolite Y; and (ii) a carrier. 15 A method according to claim 14, wherein: said formulation includes 10 to 90 wt% (preferably 30 to 80wt%) of said carrier; and / or the sum of the wt% of all carriers in said formulation is in the range 10 to 90 wt% (preferably 30 to 80wt%); and / or the sum of the wt% of all zeolites and all carriers in said formulation is at least 50 wt% (preferably at least 95wt%). 16 A method according to any of claims 12 to 15, wherein said liquid formulation includes 47 to 57 wt% of one or more liquid carriers, 40 to 50 wt% of zeolite Y and 0 to 5 wt% of dispersant(s). 17 A method according to any preceding claim, wherein, in step (ii), said first mass is contacted with a formulation comprising said zeolite Y and a mixture is produced, wherein said polymeric material in said mixture comprises 25 to 100wt% recycled material; and, optionally, said polymeric material in said mixture comprises 25 to 75wt% virgin polymer. 18 A method according to claim 17, wherein said mixture includes 1000 to 30,000 ppm (preferably 5000 to 20,000 ppm) of zeolite Y. 19 A method according to claim 17 or claim 18, wherein, in the method, said mixture produced after step (ii) is in the form of a product which is isolated from an apparatus in which it is made, wherein said product is in the form of granules or pellets or is in the form of a molded article.20 A method according to claim 19, wherein said molded article is a receptacle or container or a sheet. 21 A method according to any preceding claim, said method being used in conjunction with thermal physical processing, for example, as vacuum degassing or hot air / nitrogen stripping. 22 A method according to any preceding claim, said method comprising contacting said first mass or a mixture comprising said first mass and said zeolite Y with a second adsorbent which may not be a zeolite Y and / or may be a zeolite having complementary adsorption characteristics to that of said zeolite Y. 23 A method according to claim 22, wherein said second adsorbent is a zinc compound, for example a zinc salt of a carboxylic acid. 24 A method according to claim 22 or claim 23, wherein said second adsorbent is a bis- alkanoyloxy zinc compound and, preferably, is zinc ricinoleate. 25 A mixture in the form of a product which is a moulded article, pellets or granules which mixture comprises polymeric material and a zeolite Y. 26 A mixture according to claim 25, wherein said zeolite Y is as described in any of claims 1 to 24 and said polymeric material comprises one or more polystyrenes or one or more polyolefins. 27 A mixture according to claim 25 or claim 26, wherein said polymeric material comprises 25 to 100wt% recycled material. 28 A mixture according to any of claims 25 to 27, wherein said polymeric material in said mixture comprises at least 25wt% virgin polymer, for example virgin polyolefin. 29 A mixture according to any of claims 25 to 28, wherein: said polymeric material includes at least 90wt% of polyolefins in total; and / or said mixture includes 0.1 to 5.0wt% of said zeolite Y.30 A mixture according to any of claims 25 to 29, wherein said mixture includes zeolite Y and a second adsorbent, wherein said second adsorbent is a zinc compound, for example a zinc salt of a carboxylic acid. and, optionally, is zinc ricinoleate. 31 A mixture according to claim 30, wherein: the sum of the ppm of zeolite Y and said second adsorbent relative to the weight of polymeric material in said mixture is referred to a “SUM XX”, wherein SUM XX is at least 1000 ppm and may be in the range 1000 to 30,000 ppm, preferably 5000 to 20,000 ppm; and / or the sum of the wt% of zeolite Y and said second adsorbent (said sum being referred to as “SUM YY”) in said mixture is at least 0.1wt% and may be in the range 0.1 to 5.0wt%, preferably 0.2 to 2.5wt%. 32 A formulation for use in the method of any of claims 1 to 24 and / or incorporated in a mixture of any of claims 25 to 31, said formulation comprising: (i) zeolite Y; and (ii) a carrier. 33 A formulation according to claim 32, wherein: said formulation includes 10 to 80wt% (preferably 20 to 60wt%) of said zeolite Y; and / or said formulation includes 10 to 80wt% (preferably 20 to 60wt%) of zeolites in total; said formulation includes 10 to 90 wt% (preferably 30 to 80wt%) of said carrier; and / or the sum of the wt% of all carriers in said formulation is in the range 10 to 90 wt% (preferably 30 to 80wt%); and / or the sum of the wt% of all zeolites and all carriers in said formulation is at least 50 wt% (preferably at least 95wt%). 34 A formulation according to claim 32 or claim 33, wherein said formulation includes both zeolite Y and a second adsorbent wherein:in said formulation, a ratio defined as the weight percent of the zeolite Y divided by the weight percent of the second adsorbent is in the range 0.1 to 10.0, preferably in the range 0.5 to 2.0; the sum of the wt% of zeolite Y and said second adsorbent in said formulation is referred to as “SUM QQ”, wherein SUM QQ is at least 10wt% and optionally is in the range 10 to 80wt% or 20 to 60wt%. 35 A formulation according to claim 34, wherein said second adsorbent is a zinc compound as described in claim 23 or 24; and said second adsorbent optionally is a bis-alkanoyloxy zinc compound and / or is zinc ricinoleate. 36 A formulation according to any of claims 32 to 35, wherein said formulation is a liquid, said carrier has a boiling point at 760mmHg in accordance with ASTM D1078 in the range 275°C to 500°C and a viscosity measured using a Brookfield viscometer, spindle 2, 20rpm at 20°C in the range 50-3500cP. 37 A formulation according to any of claims 32 to 36, wherein said carrier comprises a low molecular weight wax, a triglyceride, a liquid rubber or a mineral oil.

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