Artificial turf infill coating compositions

Abstract

An artificial turf infill coating composition comprising a. from 55 wt.% to 80 wt.% of a cellulose ester, b. a plasticizer, wherein the plasticizer reduces the glass transition temperature (Tg) of the cellulose ester by at least 2°C / wt.% of plasticizer, and c. optionally, a molecular weight reducing agent (MWRA), wherein the composition has a melt flow rate (MFI) of 10 to 170 g / 10 min, as measured according to ASTM D1238 at 200°C and 2.16 kg, a number average molecular weight (Mn) of 12,000 to 30,000 g / mol, and a Tg of 55-110°C.

Description

ARTIFICIAL TURF INFILL COATING COMPOSITIONSTECHNICAL FIELD

[0001] Embodiments of the present disclosure generally relate to artificial turf infill coating compositions, and more particularly, relate to cellulosic -based artificial turf infill coating compositions.BACKGROUND

[0002] The artificial turf or synthetic turf industry has seen growing demands in recent years. The benefits of artificial turf system over conventional grass may include needing little maintenance, reducing water usage and chemical usage, consistent year- round appearance and color, and resistance to constant abrasion and flattening.

[0003] The artificial turf system may be a multilayer composite structure consisting of a shock absorption backing layer, typically made from a foamed material to provide padding, a sand layer to provide stability to the turf, a performance infill layer to provide functional benefits for ball and athlete, and finally, the turf carpet. The incumbent performance infill material has included crumb rubber or recycled rubber. However, in 2020, ECHA proposed restricted use of crumb rubber as turf infills, because the migration of polycyclic aromatic hydrocarbons may pose long-term health risks. One proposed solution to replace the crumb rubber infill layer is polyethylene (PE)-coated sand, but this technology also may face regulatory issues as ECHA progresses on a restriction proposal for microplastics. It is thought that PE-coated sand may generate and release microplastics into the environment as bits and pieces of PE break off from the sand due to tear and wear.

[0004] Accordingly, there remains a need for an artificial turf infill coating formulation that can provide good durability and weatherability during use and can biodegrade under microbial action as it enters the environment.SUMMARY

[0005] Disclosed in embodiments herein are artificial turf infill coating compositions. The artificial turf infill coating composition comprise a. from 55 wt.% to 80 wt.% of a cellulose ester, b. a plasticizer, wherein the plasticizer reduces the glass transition temperature (Tg) of the cellulose ester by at least 2°C / wt.% of plasticizer, and c. optionally, a molecular weight reducing agent (MWRA), wherein the composition has a melt flow rate (MFI) of 10 to 170 g / 10 min, as measured according to ASTM D1238 at 200°C and 2.16 kg, a number average molecular weight (Mn) of 12,000 to 30,000 g / mol, and a Tg of 55-110°C.

[0006] Further disclosed in embodiments herein are methods for manufacturing an artificial turf infill coating composition. The methods comprise mixing together a. from 55 wt.% to 80 wt.% of a cellulose ester, b. a plasticizer, wherein the plasticizer reduces the glass transition temperature (Tg) of the cellulose ester by at least 2°C / wt.% of plasticizer, and c. optionally, a molecular weight reducing agent (MWRA), to form an artificial turf infill coating composition, wherein the artificial turf infill coating composition has a melt flow rate (MFI) of 10 to 170 g / 10 min, as measured according to ASTM DI 238 at 200°C and 2.16 kg, a number average molecular weight (Mn) of 12,000 to 30,000 g / mol, and a Tg of 55-110°C.

[0007] Further disclosed in embodiments herein are pellets for use to coat artificial turf infill material. The pellets are formed from an artificial turf infill coating composition comprising a. from 55 wt.% to 80 wt.% of a cellulose ester, b. a plasticizer, wherein the plasticizer reduces the glass transition temperature (Tg) of the cellulose ester by at least 2°C / wt. % of plasticizer, and c. optionally, a molecular weight reducing agent (MWRA), wherein the composition has a melt flow rate (MFI) of 10 to 170 g / 10 min, as measured according to ASTM D1238 at 200°C and 2.16 kg, a number average molecular weight (Mn) of 12,000 to 30,000 g / mol, and a Tg of 55-110°C.

[0008] Further disclosed in embodiments herein is an artificial turf infill material. The artificial turf infill material comprises a plurality of sand particles; and a coating covering at least a portion of the plurality of sand particles; wherein the coating is formed from an artificial turf infill coating composition comprising a. from 55 wt.% to 80 wt.% of a cellulose ester, b. a plasticizer, wherein the plasticizer reduces the glass transition temperature (Tg) of the cellulose ester by at least 2°C / wt.% of plasticizer, and c. optionally, a molecular weight reducing agent (MWRA), wherein the composition has a melt flow rate (MFI) of 10 to 170 g / 10 min, as measured according to ASTM D1238 at 200°C and 2.16 kg, a number average molecular weight (Mn) of 12,000 to 30,000 g / mol, and a Tg of 55-110°C.

[0009] Additional features and advantages of the embodiments will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the art from that description or recognized by practicing the embodiments described herein. It is to be understood that both the foregoing and the following description describe various embodiments and are intended to provide an overview or framework for understanding the nature and character of the claimed subject matter.DETAILED DESCRIPTION

[0010] Reference will now be made in detail to embodiments of artificial turf infill coating compositions and methods of manufacturing thereof, as well as pellets for use to coat artificial turf infill material and artificial turf infill material. The artificial turf infill coating compositions may be used in the manufacture of artificial turf infill. The artificial turf infill may be used in artificial turf systems. It is noted, however, that this is merely an illustrative implementation of the embodiments disclosed herein. The embodiments are applicable to other technologies that are susceptible to similar problems as those discussed above.Cellulose Ester

[0011] In embodiments herein, the artificial turf infill coating composition, its method of manufacture, the pellet for formed from the artificial turf infill coatingcomposition, and the artificial turf infill comprising a coating formed from the artificial turf infill coating composition, all comprise a cellulose ester, a plasticizer, and optionally, a molecular weight reducing agent (MWRA). In one or more embodiments herein, the artificial turf infill coating composition comprises 55 wt.% to 80 wt.% of the cellulose ester. All individual values and subranges are included and disclosed herein. For example, in some embodiments, the artificial turf infill coating composition comprises 55 wt.% to 75 wt.%, 58 wt.% to 75 wt.%, or 60 wt.% to 75 wt.% of the cellulose ester.

[0012] In some embodiments herein, the artificial turf infill coating composition comprises a cellulose ester selected from the group consisting of cellulose acetate (CA), cellulose diacetate (CDA), cellulose triacetate (CTA), and combinations thereof. In some embodiments, the cellulose ester is a cellulose diacetate. In other embodiments, the cellulose ester is a mixture of cellulose diacetate and either cellulose acetate or cellulose triacetate.

[0013] The cellulose ester may have an average degree of substitution for the acetyl substituent (DSAC) that is from 0.5 to 3 and an average degree of substitution for the unsubstituted hydroxyl group (DSOH) that is from 0 to 2.5. For cellulose esters, the substitution level is usually express in terms of degree of substitution (DS), which is the average number of non-OH substituents per anhydroglucose unit (AGU). All individual values and subranges are included and disclosed herein. For example, in some embodiments, the cellulose ester may have an average degree of substitution for the acetyl substituent (DSAC) that is from 1.0 to 2.8, from 1.5 to 2.8, or from 2.0 to 2.6 and an average degree of substitution for the unsubstituted hydroxyl group (DSOH) that is from 0.5 to 2.0 or from 0.5 to 1.5. In some embodiments, the cellulose ester is a cellulose diacetate having an average degree of substitution for the acetyl substituent (DSAC) of 1.5 to 2.5 and an average degree of substitution for the unsubstituted hydroxyl group (DSOH) of 0.5 to 1.5.

[0014] Generally, conventional cellulose contains three hydroxyl groups in each AGU unit that can be substituted. As used herein, the term “degree of substitution” or“DS” refers to the average number of substituents per anhydroglucose ring of the cellulose polymer, wherein the maximum degree of substitution is 3.0. Because DS is a statistical mean value, a value of 1 does not assure that every AGU has a single substituent. In some cases, there can be unsubstituted anhydroglucose units, some with two and some with three substituents, and typically the value will be a non-integer. Total DS is defined as the average number of all of substituents per anhydroglucose unit. The degree of substitution per AGU can also refer to a particular substituent, such as, for example, hydroxyl (DS OH) or acetyl (DS AC).

[0015] In some embodiments herein, the cellulose ester may also have a number average molecular weight (Mn) ranging from 5,000 g / mol to 35,000 g / mol. All individual values and subranges are included and disclosed herein. For example, in some embodiments, the cellulose ester may have an Mn ranging from 10,000 g / mol to 35,000 g / mol or 15,000 g / mol to 35,000 g / mol.

[0016] In addition to the Mn, in some embodiments herein, the cellulose ester may also have a glass transition temperature (Tg) of from 150 °C to 210 °C. All individual values and subranges are included and disclosed herein. For example, in some embodiments, the cellulose ester resin may have a Tg of from 160 °C to 200 °C or from 175 °C to 195 °C.Plasticizer

[0017] In one or more embodiments herein, the artificial turf infill coating composition comprises 10 wt.% to 40 wt.% of the plasticizer. All individual values and subranges are included and disclosed herein. For example, in some embodiments, the artificial turf infill coating composition comprises 12 wt.% to 38 wt.% of the plasticizer.

[0018] The plasticizer may be any compound that reduces the glass transition temperature (Tg) of the cellulose ester by at least 2°C / wt.% of plasticizer. In some embodiments, the plasticizer may be any compound that reduces the glass transition temperature (Tg) of the cellulose ester by at least 2.5°C / wt.% of plasticizer. Examples of suitable plasticizers may include, but are not limited to benzoate ester, citric acidester, triacetin, tripropionin, triethyl citrate, tributyl citrate, tributyl 2-acetyl citrate, diethyl phthalate (DEP), glycerol triacetate (GTA), polyethylene glycol, and combinations thereof. In one or more embodiments herein, the plasticizer is one or more selected from the group consisting of a benzoate ester, citric acid ester, triacetin, and polyethylene glycol.

[0019] In some embodiments, the plasticizer is a blend of a hydrophilic plasticizer and a hydrophobic plasticizer, wherein the composition comprises 10 wt.% to 20 wt.%, based on the composition, of the hydrophilic plasticizer, and 10 wt.% to 20 wt.%, based on the composition, of the hydrophobic plasticizer. Examples of suitable hydrophilic plasticizers may include triacetin, citric acid esters (e.g., triethyl citrate), and polyethylene glycol. Examples of suitable hydrophobic plasticizers may include benzoate esters, tributyrin, tributyl citrate, tributyl 2-acetyl citrate, diethyl phthalate (DEP). In some embodiments, the plasticizer is a blend of: (1) a hydrophilic plasticizer selected from the group consisting of triacetin, triethyl citrate, and polyethylene glycol and (2) a hydrophobic plasticizer selected from the group consisting of benzoate esters, tributyrin, tributyl citrate, tributyl 2-acetyl citrate, and diethyl phthalate; wherein the composition comprises 10 wt.% to 20 wt.%, based on the composition, of the hydrophilic plasticizer, and 10 wt.% to 20 wt.%, based on the composition, of the hydrophobic plasticizer.Molecular Weight Reducing Agent

[0020] In some embodiments herein, the composition comprises a molecular weight reducing agent in an amount of 1 to 10 wt.%, based on the composition. All individual values and subranges are included and disclosed herein. For example, in some embodiments, the composition comprises a molecular weight reducing agent in an amount of 2 to 8 wt.% or 3 to 8 wt.%, based on the composition.

[0021] The molecular weight reducing agent may be an organic acid or acidic mineral. Examples of suitable organic acids may include, but are not limited to, citric acid, malic acid, furamic acid, or oxalic acid. Examples of suitable acidic minerals may include, but are not limited to, calcined kaolin, acidic zeolite, bentonite, smectite,montmorillonite, silica, iron (II) oxide, sphalerite, pyrite, calcined diatomaceous earth, or combinations thereof.

[0022] In one or more embodiments herein, the artificial turf infill coating composition comprises a cellulose ester that is a cellulose diacetate, a plasticizer that is a blend of a hydrophilic plasticizer and a hydrophobic plasticizer, wherein the composition comprises 10 wt.% to 20 wt.%, based on the composition, of the hydrophilic plasticizer, and 10 wt.% to 20 wt.%, based on the composition, of the hydrophobic plasticizer, and a molecular weight reducing agent that is citric acid in an amount of 3 to 8 wt.%, based on the composition.

[0023] In one or more embodiments herein, the artificial turf infill coating composition may further comprise an odor masking agent. In some embodiments herein, the artificial turf infill coating composition comprises greater than 0 wt.% to 1.0 wt.% of the odor masking agent. All individual values and subranges are included and disclosed herein. For example, in some embodiments, the artificial turf infill coating composition comprises 0.1 wt.% to 1.0 wt.% or 0.1 wt.% to 0.7 wt.% of the odor masking agent. Examples of suitable odor masking agent may include, but is not limited to, one or more of vanillin, linalool, citronellol, limonene, and geraniol.

[0024] The artificial turf infill coating compositions described herein have a melt flow rate (MFI) of 10 to 170 g / 10 min, as measured according to ASTM D1238 at 200°C and 2.16 kg, a number average molecular weight (Mn) of 12,000 to 30,000 g / mol, and a Tg of 55-110°C. In some embodiments, the artificial turf infill coating compositions described herein may have a melt flow rate (MFI) of 30 to 110 g / 10 min, as measured according to ASTM D1238 at 200°C and 2.16 kg, a number average molecular weight (Mn) of 18,000 to 30,000 g / mol, and a Tg of 60-95°C.

[0025] Also disclosed in embodiments described herein are methods of manufacturing artificial turf infill coating compositions. The method comprises mixing together a. from 55 wt.% to 80 wt.% of a cellulose ester, b. a plasticizer, wherein the plasticizer reduces the glass transition temperature (Tg) of the cellulose ester by at least 2°C / wt.% of plasticizer, and c. optionally, a molecular weight reducing agent (MWRA),to form the artificial turf infill coating composition. The cellulose ester, plasticizer, and MWRA are previously described herein, and are incorporated by reference. Also disclosed in embodiments described herein are pellets for use to coat artificial turf infill material. The pellets are formed from an artificial turf composition as previously described herein. Further disclosed in embodiments described herein are artificial turf infill materials. The artificial turf infill materials comprise a plurality of sand particles; and a coating covering at least a portion of the plurality of sand particles, wherein the coating is formed from the artificial turf infill coating composition as previously described herein.TEST METHODSMolecular Weight

[0026] The molecular weight values of cellulose acetate are calculated using? polystyrene equivalent molecular weights of the test sample dissolved in tetrahydrofuran. Samples are separated by gel permeation chromatography (GPC) using an Agilent series 1260 Liquid chromatography system and detected by Refractive index. The mobile phase is Tetrahydrofuran stabilized with BHT. The standards are monodisperse polystyrene ranging in molecular weight from 4,000,000 to 580 daltons. The results are reported in g / mol as polystyrene equivalent molecular weights.Glass Transition Temperature (Tg)

[0027] The thermal transitions of the artificial turf infill coating compositions are measured by differential scanning calorimetry (DSC). The samples are heated from 30 °C to 220 °C, back to 30 °C, and to 220 °C at 20 °C / min in nitrogen. The mid-point Tg is measured on the second heating curve.Melt Flow Index (MFI)

[0028] Pellets are dried in vacuum oven at 60 °C overnight prior to testing. MFI is measured at 200 °C using a 2.16 kg weight. The results are reported in g / 10 min.Nuclear Magnetic Resonance (NMR)

[0029] 20 mg of sample is dissolved in 1 mL deuterated dimethylsulfoxide at 80°C. 85 pL trifluoroacetic acid-d / tetramethylsilane (TFA-d / TMS) solution is added to the vial and swirled slowly. The solution is then pipetted into 5 mm NMR tube. Proton NMR data is obtained on a Broker Avance III 600 MHz spectrometer. Each spectrum is processed using ACD-Spectrus Processor software.EXAMPLES

[0030] The following specific examples are given to illustrate the process and performance properties associated with artificial turf infill coating compositions and its components. The inventive and comparative examples are provided below with the details of the formulations and results are provided in the Tables below.Table 1 - Raw MaterialsTable 2 - Resin Properties

[0031] Artificial turf infill coating compositions are formulated according to the following procedure: an 18 mm Leistritz twin screw extruder with single-hole die is used to compound CA based formulations and produce pellets. All materials are used as received without drying. All formulations are compounded at 190 to 200 °C without vacuum. The formulation details are shown in Table 3 below.Table 3 - Artificial Turf Infill Coating Compositions

[0032] The pellets are characterized by GPC, DSC, and MFI and the results are shown in Table 4.Table 4 - Artificial Turf Infill Coating Composition Properties

[0033] As shown in the Table 4, it has been surprisingly found that the artificial turf infill coating formulations of the present invention exhibit higher melt flow and hence improved coatability, improved compatibility, and improved durability when compared to the comparative examples.

[0034] The dimensions and values disclosed herein are not to be understood as being strictly limited to the exact numerical values recited. Instead, unless otherwisespecified, each such dimension is intended to mean both the recited value and a functionally equivalent range surrounding that value. For example, a dimension disclosed as “40 mm” is intended to mean “about 40 mm.”

[0035] Every document cited herein, if any, including any cross- referenced or related patent or application and any patent application or patent to which this application claims priority or benefit thereof, is hereby incorporated herein by reference in its entirety unless expressly excluded or otherwise limited. The citation of any document is not an admission that it is prior art with respect to any invention disclosed or claimed herein or that it alone, or in any combination with any other reference or references, teaches, suggests or discloses any such invention. Further, to the extent that any meaning or definition of a term in this document conflicts with any meaning or definition of the same term in a document incorporated by reference, the meaning or definition assigned to that term in this document shall govern.

[0036] While particular embodiments of the present invention have been illustrated and described, it would be obvious to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the invention. It is therefore intended to cover in the appended claims all such changes and modifications that are within the scope of this invention.

Claims

What is claimed is:

1. An artificial turf infill coating composition comprising: a. from 55 wt.% to 80 wt.% of a cellulose ester, b. a plasticizer, wherein the plasticizer reduces the glass transition temperature (Tg) of the cellulose ester by at least 2°C / wt.% of plasticizer, and c. optionally, a molecular weight reducing agent (MWRA), wherein the composition has: a melt flow rate (MFI) of 10 to 170 g / 10 min, as measured according to ASTM D1238 at 200°C and 2.16 kg, a number average molecular weight (Mn) of 12,000 to 30,000 g / mol, and a Tg of 55-110°C.

2. The artificial turf infill coating composition of claim 1, wherein the cellulose ester is one or more selected from the group consisting of cellulose acetate (CA), cellulose diacetate (CDA), cellulose triacetate (CTA), and combinations thereof.

3. The artificial turf infill coating composition of claims 1 or 2, wherein the cellulose ester has an average degree of substitution for the acetyl substituent (DSAC) that is from 0.5 to 3 and an average degree of substitution for the unsubstituted hydroxyl group (DSOH) that is from 0 to 2.5.

4. The artificial turf infill coating composition of claims 1-3, wherein the cellulose ester is cellulose diacetate having an average degree of substitution for the acetyl substituent (DSAC) of 1.5 to 2.5 and an average degree of substitution for the unsubstituted hydroxyl group (DSOH) of 0.5 to 1.5.

5. The artificial turf infill coating composition of claims 1-4, wherein the composition comprises 10 wt.% to 40 wt.% of the plasticizer.

6. The artificial turf infill coating composition of claims 1-5, wherein the plasticizer is one or more selected from the group consisting of a benzoate ester, citric acid ester, triacetin, and polyethylene glycol.

7. The artificial turf infill coating composition of claims 1-6, wherein the plasticizer is a blend of a hydrophilic plasticizer and a hydrophobic plasticizer, wherein the composition comprises 10 wt.% to 20 wt.%, based on the composition, of the hydrophilic plasticizer, and 10 wt.% to 20 wt.%, based on the composition, of the hydrophobic plasticizer.

8. The artificial turf infill coating composition of claims 1-7, wherein the composition comprises the molecular weight reducing agent in an amount of 1 to 10 wt.%, based on the composition.

9. The artificial turf infill coating composition of claim 8, wherein the molecular weight reducing agent is one or more selected from the group consisting of organic acids or acidic minerals.

10. The artificial turf infill coating composition of claim 8, wherein the molecular weight reducing agent is citric acid, calcined kaolin, or combinations thereof.

11. The artificial turf infill coating composition of claims 1-10, wherein: the cellulose ester is cellulose diacetate, the plasticizer is a blend of a hydrophilic plasticizer and a hydrophobic plasticizer, wherein the composition comprises 10 wt.% to 20 wt.%, based on the composition, of the hydrophilic plasticizer, and 10 wt.% to 20 wt.%, based on the composition, of the hydrophobic plasticizer, and the molecular weight reducing agent is citric acid in an amount of 3 to 8 wt.%, based on the composition.

12. The artificial turf infill coating composition of claims 1-11, wherein the composition further comprises an odor masking agent.

13. An artificial turf infill material comprising: a plurality of sand particles; and a coating covering at least a portion of the plurality of sand particles; wherein the coating is formed from the artificial turf infill coating composition of any one of claims 1-12.

14. A pellet for use to coat artificial turf infill material, wherein the pellet is formed from an artificial turf infill coating composition comprising: a. from 55 wt.% to 80 wt.% of a cellulose ester, b. a plasticizer, wherein the plasticizer reduces the glass transition temperature (Tg) of the cellulose ester by at least 2°C / wt.% of plasticizer, and c. optionally, a molecular weight reducing agent (MWRA), wherein the composition has: a melt flow rate (MFI) of 10 to 170 g / 10 min, as measured according to ASTM D1238 at 200°C and 2.16 kg, a number average molecular weight (Mn) of 12,000 to 30,000 g / mol, and a Tg of 55-110°C.

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