Hybrid runway article and method of making the same

Abstract

The present application provides a hybrid runway article comprising from top to bottom: (I) a topcoat layer made from a first composition comprising an externally emulsified polyurethane dispersion and rubber particles, wherein the externally emulsified polyurethane dispersion is derived from: (Ai) an isocyanate component comprising one or more compounds having at least two isocyanate groups, (Bi) an isocyanate-reactive component comprising one or more compounds having at least two isocyanate-reactive groups, (Ci) an optional catalyst, (Di) an external emulsifier, (Ei) a chain extender, and (Fi) water, and (II) a bottom layer made from a second composition comprising a 1K solventless polyurethane binder and rubber particles.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to hybrid runway articles and methods of making the same, in particular, hybrid runway articles comprising a topcoat made from a first composition comprising an externally emulsified polyurethane dispersion and rubber particles and a base layer made from a 1 K solventless polyurethane binder and rubber particles and methods of making the same. BACKGROUND

[0002] Typically, as shown in Figure 1 , a runway is a multi-layered structure comprising a cement base, a primer layer, a base layer, and a topcoat layer. The primer layer is typically a polyurethane (PU) / epoxy resin based binder. The base layer is composed of a 1 K non-solvent PU binder and EPDM particles. The top layer is composed of a solventless 2K PU and EPDM particles. Currently, to make the topcoat layer, EPDM rubber particles and solventless 2K PU are blended in a drum under agitation to obtain a homogeneous mixture, which is then spray applied on the surface of the base layer. Typically, to obtain a high quality topcoat layer, a double-coat spray process is required. The time interval between the two coats is about 24 hours to fully achieve the target mechanical strength within one day after application.

[0003] For the current solventless 2K PU system, there are many problems during the spray process. First, the pot life is short. The solventless 2K PU system typically contains two components, including an isocyanate / prepolymer component and a polyol. Before spraying, the two components need to be mixed under mechanical agitation, and then the resulting mixture is loaded into a spray machine for spraying. Typically, the solventless 2K PU system will start to gel within 0.5 hours after the two components are mixed. The gelation (residue) will easily clog the spray gun, so an organic solvent is needed to clean the spray machine every 2 to 3 hours, which will create a VOC problem. In addition, most contractors do not have the certification to use, transport, and store organic solvents. Second, the curing time of the solventless 2K PU system usually requires overnight, so the work efficiency is low.

[0004] Therefore, there is still a continuing need for a runway article that exhibits excellent mechanical properties such as tensile strength and elongation at break, short curing time, and no VOC problem.

[0005] After continuous exploration, we have surprisingly found a hybrid runway that can achieve one or more of the above objectives. The present inventors replace the current solventless 2K PU system as the top coat binder of the runway with an externally emulsified polyurethane dispersion. This replacement brings at least the following advantages compared to the solventless 2K PU system: no pot life limitation; no gelling problem; and no need for solvents to clean the spray machine. For the runway construction party, they do not need to worry about the trouble caused by organic solvents. The present disclosure has the following advantages: less VOC problem; less health and safety risk during processing; short drying (curing) time after spraying (within 2-3 hours), and higher application efficiency; better mechanical properties than solventless 2K PU, and less PU resin usage than solventless 2K PU while maintaining good PUD coverage on EPDM. SUMMARY

[0006] The present disclosure provides a hybrid runway with short drying time, good mechanical properties, and no VOC problem.

[0007] In a first aspect of the present disclosure, the present disclosure provides a hybrid runway article comprising, from top to bottom:

[0008] (I) a top coat made from a first composition comprising an externally emulsified polyurethane dispersion and rubber particles, wherein the externally emulsified polyurethane dispersion is derived from: (Ai) an isocyanate component comprising one or more compounds having at least two isocyanate groups, (Bi) an isocyanate-reactive component comprising one or more compounds having at least two isocyanate-reactive groups, (Ci) an optional catalyst, (Di) an external emulsifier, (Ei) a chain extender, and (Fi) water, and

[0009] (II) a bottom layer made from a second composition comprising a 1K solventless polyurethane binder and rubber particles.

[0010] In a second aspect of the present disclosure, the present disclosure provides a method for producing the hybrid runway article of the first aspect, the method comprising:

[0011] i) applying a second composition comprising a 1K solventless polyurethane binder and rubber particles on a ground surface;

[0012] ii) curing the second composition to obtain a bottom layer;

[0013] iii) applying a first composition comprising an externally emulsified polyurethane dispersion and rubber particles, wherein the externally emulsified polyurethane dispersion is derived from: (Ai) an isocyanate component comprising one or more compounds having at least two isocyanate groups, (Bi) an isocyanate-reactive component comprising one or more compounds having at least two isocyanate-reactive groups, (Ci) an optional catalyst, (Di) an external emulsifier, (Ei) a chain extender, and (Fi) water;

[0014] iv) drying the first composition to form a topcoat layer on the base layer.

[0015] In a third aspect of the present disclosure, the present disclosure provides the use of an externally emulsified polyurethane dispersion in a topcoat layer of a running track article, wherein the externally emulsified polyurethane dispersion is derived from: (Ai) an isocyanate component comprising one or more compounds having at least two isocyanate groups, (Bi) an isocyanate-reactive component comprising one or more compounds having at least two isocyanate-reactive groups, (Ci) an optional catalyst, (Di) an external emulsifier, (Ei) a chain extender, and (Fi) water.

[0016] According to preferred embodiments of the first to third aspects, the externally emulsified polyurethane dispersion does not comprise any cationic or anionic hydrophilic side groups or groups convertible to cationic or anionic hydrophilic side groups covalently attached to the polyurethane backbone.

[0017] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the application as claimed. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 is a schematic representation of a prior art running track. DETAILED DESCRIPTION

[0019] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as those commonly understood by one of ordinary skill in the art to which this application belongs. Also, all publications, patent applications, patents, and other references mentioned herein are incorporated by reference.

[0020] As disclosed herein, the term “composition”, “formulation” or “mixture” refers to a physical blend of different components, which is obtained by simply mixing the different components by physical means.

[0021] As disclosed herein, “and / or” means “and, or as an alternative”. All ranges include the end values, unless otherwise indicated.

[0022] As disclosed herein, “solvent” means an organic solvent, unless otherwise indicated.

[0023] Externally emulsified polyurethane dispersions

[0024] The topcoat layer is formed by applying a first composition comprising an externally emulsified polyurethane dispersion and rubber particles on the base layer.

[0025] The topcoat layer is made from a first composition comprising an externally emulsified polyurethane dispersion and rubber particles, wherein the externally emulsified polyurethane dispersion is derived from: (Ai) an isocyanate component comprising one or more compounds having at least two isocyanate groups, (Bi) an isocyanate-reactive component comprising one or more compounds having at least two isocyanate-reactive groups, (Ci) an optional catalyst, (Di) an external emulsifier, (Ei) a chain extender, and (Fi) water.

[0026] The external emulsifier or a residual portion of the external emulsifier is not covalently attached to the main chain of the polyurethane.

[0027] According to one preferred embodiment, the externally emulsified polyurethane dispersion is aqueous and essentially free of any organic solvent intentionally added thereto. Typically, the aqueous dispersion has at most about 1 wt.-% of organic solvent, based on the total weight of the dispersion. Preferably, the aqueous dispersion has at most about 2000 parts per million (ppm), more preferably at most about 1000 ppm, even more preferably at most about 500 ppm and most preferably at most traces of organic solvent.

[0028] As described herein, the expression "externally emulsified polyurethane dispersion" refers to a polyurethane dispersion comprising a limited amount of, preferably not comprising, an internal emulsification component and thus relying mainly on the emulsifying function of an "external emulsifier" (i.e. an ionic or non-ionic emulsifier, which is not covalently bonded to the main chain within the polyurethane particles dispersed in the liquid medium, in particular via a urethane bond originating from a reaction between an isocyanate group and an isocyanate-reactive group such as a hydroxyl group) to stabilize the polyurethane dispersion.

[0029] According to one embodiment of the present disclosure, the externally emulsified polyurethane dispersion can be prepared by the steps of: (i) reacting (Ai) an isocyanate component comprising one or more compounds having at least two isocyanate groups with (Bi) an isocyanate-reactive component comprising one or more compounds having at least two isocyanate-reactive groups in the presence of (Ci) an optional catalyst to form a prepolymer; (ii) dispersing the prepolymer obtained in step (i) in (Fi) water in the presence of (Di) an external emulsifier to form an emulsion; and (iii) further adding (Ei) a chain extender to the emulsion to react with the prepolymer obtained in step (ii) and form the externally emulsified polyurethane dispersion.

[0030] According to one embodiment of the present disclosure, the prepolymer prepared in step (i) does not contain any ionic internal emulsifiers or residual portions of ionic internal emulsifiers covalently bonded to the urethane prepolymer chain. According to another embodiment of the present disclosure, the polyurethane chains in the prepolymer prepared in step (i) do not contain any cationic or anionic pendant groups.

[0031] In a preferred embodiment of the present disclosure, the externally emulsified polyurethane dispersion does not contain any internal emulsifiers and there are no anionic or cationic salt groups present in the backbone of the polyurethane particles dispersed in the externally emulsified PUD.

[0032] The particle size of the PU particles dispersed in the externally emulsified PUD is from 20 nm to 5,000 nm, preferably from 50 nm to 2,000 nm, and more preferably from 50 nm to 1,000 nm.

[0033] The externally emulsified polyurethane dispersion can have any suitable polyurethane particle solids loading, but typically the solids loading is from about 1 wt% to about 70 wt% solids, preferably at least about 2 wt%, more preferably at least about 4 wt%, more preferably at least about 6 wt%, more preferably at least about 15 wt%, more preferably at least about 25 wt%, more preferably at least about 30 wt%, most preferably at least about 40 wt%, to at most about 70 wt%, preferably at most 68 wt%, more preferably at most about 65 wt%, more preferably at most about 63 wt%, most preferably at most about 60 wt%, of the total weight of the dispersion.

[0034] Typically, the externally emulsified PUD has a viscosity of at least about 10 mPa.s to at most about 5,000 mPa.s, preferably at least about 20 mPa.s to at most about 2,000 mPa.s, more preferably at least about 30 mPa.s to at most about 1000 mPa.s.

[0035] Isocyanate component (Ai)

[0036] In various embodiments, the average functionality of the isocyanate component (Ai) is at least about 2.0, preferably from about 2 to 10, more preferably from about 2 to about 8, and most preferably from about 2 to about 6. In some embodiments, the isocyanate component includes one or more polyisocyanate compounds including at least two isocyanate groups. Suitable polyisocyanate compounds include aromatic, aliphatic, cycloaliphatic, and araliphatic polyisocyanates having two or more isocyanate groups. In preferred embodiments, the polyisocyanate component includes a polyisocyanate compound selected from the group consisting of C4-C 12 aliphatic polyisocyanates, C6-C 15cycloaliphatic or aromatic polyisocyanates, C7-C 15 aromatic aliphatic polyisocyanates, and combinations thereof. In another preferred embodiment, suitable polyisocyanate compounds include m-phenylene diisocyanate, 2,4- and / or 2,6-toluene diisocyanate (TDI), the various isomers of diphenylmethane diisocyanate (MDI), carbodiimide-modified MDI products, hexamethylene-1,6-diisocyanate, tetramethylene-1,4-diisocyanate, cyclohexane-1,4-diisocyanate, hexahydrotoluene diisocyanate, hydrogenated MDI, naphthylene-1,5-diisocyanate, isophorone diisocyanate (IPDI), or mixtures thereof. In another preferred embodiment, suitable polyisocyanate compounds include isophorone diisocyanate (IPDI).

[0037] Alternatively or additionally, the polyisocyanate component can also comprise an isocyanate prepolymer having an isocyanate functionality in the range of 2 to 10, preferably 2 to 8, more preferably 2 to 6. The isocyanate prepolymer can be obtained by reacting the monomeric isocyanate component described above with one or more isocyanate-reactive compounds selected from the group consisting of ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,4-butynediol, 1,5-pentanediol, neopentyl glycol, bis(hydroxymethyl)cyclohexanes such as 1,4-bis(hydroxymethyl)cyclohexane, 2-methylpropane-1,3-diol, methylpentanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, dipropylene glycol, polypropylene glycol, dibutylene glycol, and polybutylene glycol. Suitable prepolymers for use as the polyisocyanate component are prepolymers having an NCO group content of 2 to 40 wt.%, more preferably 4 to 30 wt.%. These prepolymers are preferably prepared by the reaction of diisocyanates and / or polyisocyanates with materials comprising lower molecular weight diols and triols. A separate example is an aromatic polyisocyanate containing urethane groups, having an NCO content of preferably 5 to 40 wt.%, more preferably 20 to 35 wt.%, which is obtained by the reaction of diisocyanates and / or polyisocyanates with, for example, lower molecular weight diols, triols, oxyalkylene diols, oxyalkylene diols, or polyoxyalkylene diols having a molecular weight of up to about 800. These polyols can be used individually or in mixtures of oxyalkylene diols and / or polyoxyalkylene diols. For example, diethylene glycol, dipropylene glycol, polyoxyethylene glycol, ethylene glycol, propylene glycol, butylene glycol, polyoxypropylene glycol, and polyoxypropylene-polyoxyethylene glycol can be used. Polyester polyols can also be used, as well as alkane diols such as butanediol. Other useful diols include bis-hydroxyethyl- or bis-hydroxypropyl-bisphenol A, cyclohexanedimethanol, and bis-hydroxyethyl hydroquinone.

[0038] Also advantageously used for the isocyanate component are so-called modified polyfunctional isocyanates, i.e. products obtained by chemical reactions of the above-mentioned isocyanate compounds. Exemplary are polyisocyanates containing esters, ureas, biurets, allophanates, and preferably carbodiimides and / or uretonimines. Also liquid polyisocyanates containing carbodiimide groups, uretonimine groups and / or isocyanurate rings can be used, which have an isocyanate group (NCO) content of 12 to 40 wt.-%, more preferably 20 to 35 wt.-%. These include, for example, polyisocyanates based on 4,4'-2,4'- and / or 2,2'-diphenylmethane diisocyanate and the corresponding isomer mixtures, 2,4- and / or 2,6-toluene diisocyanate and the corresponding isomer mixtures; mixtures of diphenylmethane diisocyanate and PMDI; and mixtures of toluene diisocyanate and PMDI and / or diphenylmethane diisocyanate.

[0039] Generally, the amount of the isocyanate component (Ai) can vary based on the actual requirements of the runway article. For example, as one exemplary embodiment, the isocyanate component (Ai) can be used in an amount to ensure that the content of isocyanate groups in the isocyanate component (Ai) is about 101 mole % to about 300 mole %, preferably about 110 mole % to about 280 mole %, more preferably about 150 mole % to about 250 mole %, more preferably about 170 mole % to 240 mole %, more preferably about 180 mole % to 230 mole %, more preferably 190 mole % to 230 mole %, based on the total mole content of isocyanate-reactive groups in the isocyanate-reactive component (Bi).

[0040] Isocyanate-reactive component (Bi )

[0041] In another embodiment of the present disclosure, the isocyanate-reactive component comprises one or more polyols selected from the group consisting of aliphatic polyols comprising at least two hydroxyl groups, cycloaliphatic or aromatic polyols comprising at least two hydroxyl groups, araliphatic polyols comprising at least two hydroxyl groups, polyester polyols, and mixtures thereof. Preferably, the polyols are selected from the group consisting of C2-C 16 aliphatic polyols comprising at least two hydroxyl groups, C6-C 15 cycloaliphatic or aromatic polyols comprising at least two hydroxyl groups, C7-C 15 araliphatic polyols, polyester polyols having a molecular weight of 100 to 5,000, polyether polyols having a molecular weight of 800 to 12,000, and combinations thereof.

[0042] In one embodiment of the disclosure, the isocyanate-reactive component comprises a mixture of two or more different polyols, such as a mixture of two or more polyether polyols, a mixture of two or more polyester polyols, a mixture of at least one polyether polyol and at least one polyester polyol, or a mixture of a polyester polyol and a monomeric polyol.

[0043] In one embodiment, the isocyanate-reactive component is a polyether polyol having a functionality (average number of isocyanate-reactive groups, in particular hydroxyl groups, in a polyol molecule) of 2.0 to 3.0 and a weight average molecular weight (Mw) of 800 to 12,000 g / mol, preferably 1,000 to 10,000 g / mol, preferably 1,000 to 8,000 g / mol, more preferably 1,000 to 4,000 g / mol. Polyether polyols are typically prepared by polymerization of one or more alkylene oxides selected from propylene oxide (PO), ethylene oxide (EO), butylene oxide, tetrahydrofuran, and mixtures thereof, in the presence of a catalyst, with an appropriate initiator molecule. Typical initiator molecules include compounds having at least 2, preferably 4 to 8, hydroxyl groups in the molecule or having two or more primary amine groups. Suitable initiator molecules are, for example, selected from aniline, EDA, TDA, MDA, and PMDA, more preferably selected from TDA and PMDA, most preferably TDA. When TDA is used, all isomers can be used individually or in any desired mixture. For example, 2,4-TDA, 2,6-TDA, a mixture of 2,4-TDA and 2,6-TDA, 2,3-TDA, 3,4-TDA, a mixture of 3,4-TDA and 2,3-TDA, and mixtures of all the above isomers can be used. By means of an initiator molecule having at least 2 and preferably 2 to 8 hydroxyl groups in the molecule, it is preferred to use trimethylolpropane, glycerol, pentaerythritol, castor oil, sugar compounds such as, for example, glucose, sorbitol, mannitol, and sucrose, polyhydric phenols, a methylol phenol-formaldehyde resin such as an oligomeric condensation product of phenol and formaldehyde, and a Mannich condensate of phenol, formaldehyde, and a dialkanol amine, and melamine. Catalysts for the preparation of polyether polyols can include basic catalysts for anionic polymerization such as potassium hydroxide, or Lewis acid catalysts for cationic polymerization such as boron trifluoride. Suitable polymerization catalysts can include potassium hydroxide, cesium hydroxide, boron trifluoride, or a double cyanide complex (DMC) catalyst such as zinc hexacyanocobaltate or a quaternary phosphonium onium compound. In one preferred embodiment of the disclosure, the polyether polyol includes (methoxy)polyethylene glycol (MPEG), polyethylene glycol (PEG), poly(propylene glycol), or a copolymer of ethylene oxide and propylene oxide having primary and secondary hydroxyl end groups. Examples of commercially available polyether polyols include, but are not limited to, those available under the trade designation VORANOL TMsold under the trade name VORANOL TM 2000 LM and VORANOL TM 4000 LM, VORANOL TM 3010 and VORANOL TM 222-056 and the like.

[0044] In preferred embodiments, the isocyanate-reactive component is a polyester polyol having a molecular weight of 500 g / mol to 5,000 g / mol, preferably 1000 g / mol to 3,000 g / mol, in order to achieve good film formation and elasticity of the PUD top film. The polyester polyol is typically obtained by reacting a polyfunctional alcohol having 2 to 12 carbon atoms, preferably 2 to 6 carbon atoms, with a polyfunctional carboxylic acid or anhydride / ester thereof having 2 to 12 carbon atoms, preferably 2 to 6 carbon atoms. Typical polyfunctional alcohols for making the polyester polyol are preferably diols or triols and include ethylene glycol, propylene glycol, butylene glycol, pentane diol, or hexane diol. Typical polyfunctional carboxylic acids can be aliphatic, alicyclic, araliphatic, aromatic, or heterocyclic, and can be substituted, for example, by halogen atoms, and / or can be saturated or unsaturated. Preferably, the polyfunctional carboxylic acid is selected from the group consisting of suberic acid, azelaic acid, phthalic acid, isophthalic acid, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, tetrachlorophthalic anhydride, endomethylenetetrahydrophthalic anhydride, glutaric anhydride, alkenyl succinic acid, maleic acid, maleic anhydride, fumaric acid, dimer fatty acid. Preference is given to di-carboxylic acids of the general formula HOOC-(CH2) y -COOH, wherein y is an integer from 1 to 20, preferably an even number from 2 to 20. The polyester polyol is preferably terminated with at least two hydroxyl groups. In preferred embodiments, the hydroxyl functionality of the polyester polyol is from 2 to 10, preferably from 2 to 6. In another embodiment, the OH value of the polyester polyol is from 80 mg KOH / g to 2,000 mg KOH / g, preferably from 150 mg KOH / g to 1,000 mg KOH / g, and more preferably from 200 mg KOH / g to 500 mg KOH / g. Various molecular weights are contemplated for the polyester polyol. For example, the number average molecular weight of the polyester polyol can be from about 500 g / mol to about 5,000 g / mol, preferably from about 600 g / mol to about 4,000 g / mol, preferably from about 500 g / mol to about 3,000 g / mol, preferably from about 1000 g / mol to about 2,500 g / mol, preferably from about 1200 g / mol to about 2,000 g / mol, and more preferably from about 1,500 g / mol to about 1,800 g / mol.

[0045] Alternatively, the polyester polyols include lactone-based polyester diols, which are homopolymers or copolymers of lactones, preferably terminal hydroxyl group functional addition products of lactones with a suitable difunctional initiator molecule. Preferred lactone-based polyester diols include compounds represented by the general formula HO-(CH2) z -COOH, wherein z is an integer from 1 to 20, and one hydrogen atom of the methylene unit can also be replaced by a Ci to C4alkyl group. Exemplary lactone-based polyester diols include ε-caprolactone, β-propiolactone, γ-butyrolactone, methyl-ε-caprolactone, or mixtures thereof.

[0046] Generally, the amount of isocyanate-reactive component (Bi) used herein can be used in an amount to ensure that the isocyanate-reactive groups in the isocyanate-reactive component (Bi) are about 50 mole % to about 98 mole %, preferably about 60 mole % to about 97 mole %, more preferably about 70 mole % to about 96 mole %, more preferably about 80 mole % to about 96 mole %, more preferably about 85 mole % to about 95 mole %, based on the total mole content of isocyanate groups in the isocyanate component (Ai).

[0047] In the context of the present disclosure, other compounds containing functional groups that can react with isocyanate groups, such as chain extenders and water, are not within the definition of the so-called “isocyanate-reactive component”. Chain extenders and water can be clearly distinguished from the isocyanate-reactive component by the molecular structure or the point in time at which they are added.

[0048] Catalyst (Ci )

[0049] The catalyst (Ci) can include any substance that can promote the reaction between the isocyanate groups and the isocyanate-reactive groups. Without being limited by theory, the catalyst can include, for example, glycine salts; tertiary amines; tertiary phosphines such as trialkyl phosphines and dialkyl benzyl phosphines; morpholine derivatives; piperazine derivatives; chelates of various metals such as those obtainable from acetylacetone, benzoylacetone, trifluoroacetylacetone, ethyl acetoacetate, and the like with metals such as Be, Mg, Zn, Cd, Pd, Ti, Zr, Sn, As, Bi, Cr, Mo, Mn, Fe, Co, and Ni; acidic metal salts of strong acids such as ferric chloride and tin chloride; salts of various metals such as alkali metals, alkaline earth metals, Al, Sn, Pb, Mn, Co, Ni, and Cu with organic acids; organotin compounds such as tin(II) salts of organic carboxylic acids, for example, tin(II) diacetate, tin(II) dioctoate, tin(II) diethylhexanoate, and tin(II) dilaurylate, and dialkyl tin(IV) salts of organic carboxylic acids, for example, dibutyl tin diacetate, dibutyl tin dilaurylate, dibutyl tin maleate, and dioctyl tin diacetate; bismuth salts of organic carboxylic acids, for example, bismuth octoate; organometallic derivatives of trivalent and pentavalent As, Sb, and Bi, and carbonyl metals of iron and cobalt; or mixtures thereof.

[0050] Tertiary amine catalysts include organic compounds comprising at least one tertiary nitrogen atom and capable of catalyzing the hydroxyl / isocyanate reaction. By way of example and not limitation, tertiary amine, morpholine derivative, and piperazine derivative catalysts can include triethylenediamine, tetramethylethylenediamine, pentamethyldiethylenetriamine, bis(2-dimethylaminoethyl) ether, triethylamine, tripropylamine, tributylamine, tripentylamine, pyridine, quinoline, dimethylpiperazine, piperazine, N-ethylmorpholine, 2-methylpropanediamine, methyltriethylenediamine, 2,4,6-(trisdimethylamino-methyl)phenol, N,N',N"-tris(dimethylamino-propyl) s-triazine, or mixtures thereof.

[0051] Generally, the content of the catalyst used herein is greater than or equal to 0 wt% and is at most 1.0 wt%, preferably at most 0.5 wt%, more preferably at most 0.05 wt%, more preferably at most 0.02 wt%, based on the total weight of the isocyanate component (Ai) and the isocyanate-reactive component (Bi). It can be seen that the content of the catalyst is calculated as an additional amount when the total amount of the isocyanate component (Ai) and the isocyanate-reactive component (Bi) is taken as 100 wt%.

[0052] External emulsifier (Di)

[0053] The external emulsifier can be cationic, anionic or non-ionic, and is preferably anionic. Suitable classes of emulsifiers include, but are not limited to, ethoxylated phenol sulfates such as poly(oxy-1,2-ethanediyl) a-sulfo- w(nonylphenoxyl) salts; alkali metal fatty acid salts such as alkali metal oleates and stearates; alkali metal C12-C16 alkyl sulfates such as alkali metal lauryl sulfates; alkali metal C12-C16 alkyl benzene sulfonates such as sodium salts of branched and linear dodecyl benzene sulfonic acid; anionic and non-ionic fluorocarbon emulsifiers such as fluorinated C4-C16 alkyl esters and alkali metal C4-C16 perfluoroalkyl sulfonates. Exemplary external emulsifiers include disodium octadecyl sulfosuccinate, sodium dodecyl benzene sulfonate (SDBS), sodium stearate, and ammonium stearate. The polyurethane dispersion can be prepared by any suitable method, such as those well known in the art.

[0054] According to embodiments of the present disclosure, the amount of external emulsifier is from 0.01 wt% to 10 wt%, or from 0.05 wt% to 8 wt%, from 0.1 wt% to 7 wt%, or from 0.2 wt% to 6 wt%, or from 0.5 wt% to 5 wt%, or from 1 wt% to 5 wt%, or from 1 wt% to 3 wt%, based on the total weight of the external emulsified PUD.

[0055] Chain extender (Ei )

[0056] According to one embodiment of the present disclosure, the chain extender (Ei) can be a polyamine, preferably selected from the group consisting of C4-C15 cycloaliphatic polyamines comprising at least two amine groups within the aliphatic ring, for example piperazine; C2-C16 aliphatic polyamines comprising at least two amine groups, for example ethylenediamine; C4-C15 cycloaliphatic polyamines comprising at least two amine groups outside the aliphatic ring, such as cyclohexanediamine, or C5-C15 aromatic polyamines comprising at least two amine groups, such as p-xylenediamine; and C7-C15 araliphatic polyamines comprising at least two amine groups. According to a preferred embodiment, the chain extender is a C4-C15 cycloaliphatic polyamine comprising at least two amine groups within the aliphatic ring or a C4-C15 cycloaliphatic polyamine comprising at least two amine groups outside the aliphatic ring, more preferably a C4-C15 cycloaliphatic polyamine comprising two secondary amine groups within the aliphatic ring or a C4-C15 cycloaliphatic polyamine comprising two primary or secondary amine groups outside the aliphatic ring. Preferably, the amine chain extender is piperazine.

[0057] According to embodiments of the present disclosure, the chain extender is used in an amount to ensure a NCO blockage of the prepolymer of about 70.0% to about 98.5%, or a lower limit of about 70.0%, 75.0%, or 80.0% to an upper limit of about 98.0%, 97.0%, 95.0%, or 85.0%, wherein the prepolymer is prepared by (i) reacting an isocyanate component comprising one or more compounds having at least two isocyanate groups (Ai) with an isocyanate-reactive component comprising one or more compounds having at least two isocyanate-reactive groups (Bi) in the presence of (Ci) an optional catalyst. The “NCO blockage” is defined as the mole percent of NCO groups in the prepolymer that are blocked by a chain extender such as piperazine.

[0058] 1 K solventless polyurethane adhesive

[0059] 1K solventless polyurethane adhesive can also be referred to as a one-component solventless polyurethane prepolymer comprising a reaction product formed by reacting (Aii) an isocyanate component comprising one or more compounds having at least two isocyanate groups, (Bii) an isocyanate-reactive component comprising one or more compounds having at least two isocyanate-reactive groups, wherein the detailed description of (Aii) an isocyanate component comprising one or more compounds having at least two isocyanate groups can refer to (Ai) an isocyanate component comprising one or more compounds having at least two isocyanate groups, and the detailed description of (Bii) an isocyanate-reactive component comprising one or more compounds having at least two isocyanate-reactive groups can refer to (Bi) an isocyanate-reactive component comprising one or more compounds having at least two isocyanate-reactive groups. The 1K solventless polyurethane adhesive is moisture-curable.

[0060] Typically, the 1K solventless polyurethane adhesive has at most about 1 wt% of organic solvent, based on the total weight of the dispersion. Preferably, the aqueous dispersion has at most about 2000 parts per million (ppm), more preferably at most about 1000 ppm, even more preferably at most about 500 ppm, and most preferably at most trace amounts of organic solvent.

[0061] Preferably, the 1K solventless polyurethane adhesive comprises a reaction product formed by reacting a diphenylmethane diisocyanate (MDI) component and a polyol. The diphenylmethane diisocyanate (MDI) component can also be replaced with a TDI component, an IPDI component, an HDI component, an H12MDI component, or a mixture thereof.

[0062] In embodiments of this disclosure, based on the total weight of the diphenylmethane diisocyanate component and the polyol, the 1K solvent-free polyurethane adhesive comprises a reaction product formed by reacting 15% to 50% by weight of the diphenylmethane diisocyanate component and 50% to 85% by weight of the polyol. The diphenylmethane diisocyanate (MDI) component may also be replaced by a TDI component, an IPDI component, an HDI component, an H12MDI component, or a mixture thereof.

[0063] Based on the total weight of the diphenylmethane diisocyanate component, the diphenylmethane diisocyanate component may comprise 90 wt% to 100 wt% of 4,4'-diphenylmethane diisocyanate. This includes all individual values ​​and sub-ranges from 90 wt% to 100 wt%; for example, based on the total weight of the diphenylmethane diisocyanate component, the diphenylmethane diisocyanate component may comprise 90 wt%, 93 wt%, or 95 wt% to 100 wt%, 99 wt%, or 97 wt% of 4,4'-diphenylmethane diisocyanate. The diphenylmethane diisocyanate component may also comprise 2,2'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, and / or impurities known in the art.

[0064] Polyols can have a weight-average molecular weight from 300 g / mol to 12,000 g / mol. This includes all individual values ​​and sub-ranges from 300 g / mol to 12,000 g / mol; for example, polyols can have a weight-average molecular weight from the lower limit of 300 g / mol, 500 g / mol, 750 g / mol, 1,000 g / mol, 1,250 g / mol, 1,500 g / mol, 1,750 g / mol, 2,000 g / mol or 2,250 g / mol to the upper limit of 12,000 g / mol, 11,000 g / mol, 10,000 g / mol, 9,000 g / mol, 8,000 g / mol, 7,000 g / mol, 6,000 g / mol, 5,000 g / mol or 4,500 g / mol.

[0065] Polyols can have an average functionality of 1.5 to 3.5. This includes all individual values ​​and sub-ranges from 1.5 to 3.5; for example, polyols can have an average functionality from a lower limit of 1.5, 1.6, 1.7 or 1.8 to an upper limit of 3.5, 3.4, 3.3 or 3.2.

[0066] Polyols can be polyether polyols, polyester polyols, and combinations thereof. Examples of commercially available polyols include, but are not limited to, those marketed under the trade name VORANOL. TM Polyols for sale, such as VORANOL TM WD 2130 and VORANOLTM 4000 LM, TERCAROL TM and VORATEC TM etc.

[0067] The polyol can include a polyether polyol. The polyether polyol can be prepared by known methods. For example, the polyether polyol can be prepared by anionic polyaddition of at least one alkylene oxide (e.g., ethylene oxide or 1,2-propylene oxide or 1,2-propylene oxide and ethylene oxide). A starting compound, which can be referred to as an initiator, is any organic compound that will be alkoxylated in the polymerization reaction. The initiator can include 2 or more hydroxyl and / or amine groups. Mixtures of starting compounds / initiators can be used. Examples of initiator compounds include, but are not limited to, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, 1,4-butanediol, 1,6-hexanediol, 1,8-octanediol, cyclohexanedimethanol, glycerol, trimethylolpropane, trimethylolethane, pentaerythritol, sorbitol, sucrose, and alkoxylates (particularly ethoxylates and / or propoxylates) of any of these, polyamines, dialkanolamines.

[0068] The polyol can include a polyester polyol. The polyester polyol can be made from, for example, organic dicarboxylic acids having 2 to 12 carbon atoms (including aromatic dicarboxylic acids having 8 to 12 carbon atoms) and polyols (including diols having 2 to 12 carbon atoms). Examples of suitable dicarboxylic acids are succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, decane dicarboxylic acid, maleic acid, fumaric acid, phthalic acid, isophthalic acid, terephthalic acid, and the isomeric naphthalene dicarboxylic acids. The dicarboxylic acids can be used individually or in mixtures with one another. The free dicarboxylic acids can be replaced by the corresponding dicarboxylic acid derivatives, such as, for example, the dicarboxylic acid esters or dicarboxylic anhydrides of alcohols having 1 to 4 carbon atoms. Some specific examples can use mixtures of dicarboxylic acids including, for example, 20 parts by weight to 35 parts by weight of succinic acid, 35 parts by weight to 50 parts by weight of glutaric acid, and 20 parts by weight to 50 parts by weight of adipic acid, and mixtures of adipic acid, and phthalic acid and / or phthalic anhydride and adipic acid, mixtures of phthalic acid or phthalic anhydride, isophthalic acid, and adipic acid, or mixtures of succinic acid, glutaric acid, and adipic acid, and mixtures of terephthalic acid and adipic acid, or mixtures of succinic acid, glutaric acid, and adipic acid. Examples of diols and polyols are ethylene glycol, diethylene glycol, 1,2- and 1,3-propanediol, dipropylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,10-decanediol, glycerol, trimethylolpropane, and the like. Some specific examples provide ethylene glycol, diethylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, or a mixture of at least two of said diols, in particular a mixture of 1,4-butanediol, 1,5-pentanediol, and 1,6-hexanediol. In addition, polyester polyols made from lactones (e.g., e-caprolactone) or hydroxycarboxylic acids (e.g., w-hydroxycaproic acid and hydroxybenzoic acid) can also be employed.

[0069] For example, the polyester polyol can be prepared by polycondensation of an organic polycarboxylic acid and / or derivatives thereof with a polyol in a molar ratio of 1:1 to 1:1.8, for example 1:1.05 to 1:1.2.

[0070] The reaction product can be formed by reacting 15 weight percent to 50 weight percent of the diphenylmethane diisocyanate component and 50 weight percent to 85 weight percent of the polyol, based on the total weight of the diphenylmethane diisocyanate component and the polyol. All individual values and subranges from 15 weight percent to 50 weight percent of the diphenylmethane diisocyanate component are included; for example, the reaction product can be formed by reacting 15 weight percent, 20 weight percent, or 25 weight percent of a lower limit to 50 weight percent, 45 weight percent, or 40 weight percent of an upper limit of the diphenylmethane diisocyanate component, based on the total weight of the diphenylmethane diisocyanate component and the polyol.

[0071] All individual values and subranges from 50 wt% to 85 wt% of the polyol; for example, the reaction product can be formed by reacting 50 wt%, 55 wt%, or 60 wt% lower to 85 wt%, 80 wt%, or 75 wt% upper of the polyol, based on the total weight of the diphenylmethane diisocyanate and the polyol.

[0072] The reaction product can be formed using known equipment and reaction conditions. For example, the reactants (i.e., the diphenylmethane diisocyanate component and the polyol) can be heated to any desired temperature for a specified time sufficient to achieve the desired chemical / physical conversion. By way of example, the reaction product can be formed at a temperature of 20 °C to 100 °C; the reaction can occur, for example, for a period of about 5 minutes to about 8 hours; and the reaction can be conducted in an inert environment, such as a nitrogen environment.

[0073] The 1K polyurethane adhesive disclosed herein can also use an aliphatic isocyanate.

[0074] The aliphatic isocyanate can have an average functionality of 1.5 to 3.5. All individual values and subranges from 1.5 to 3.5 are included; for example, the polyol can have an average functionality of 1.5, 1.6, 1.7, 1.8, or 2.0 lower to 3.5, 3.4, 3.3, 3.2, or 3.0 upper.

[0075] Examples of the aliphatic isocyanate include, but are not limited to, isophorone diisocyanate, isophorone diisocyanate trimer, hexamethylene diisocyanate trimer, methylene dicyclohexyl diisocyanate, and hydrogenated methylene dicyclohexyl diisocyanate. Preferably, the aliphatic isocyanate is selected from isophorone diisocyanate, isophorone diisocyanate trimer, hexamethylene diisocyanate trimer, and combinations thereof.

[0076] The 1K polyurethane adhesive disclosed herein includes 0.5 wt% to 20 wt% of the aliphatic isocyanate, based on the total weight of the diphenylmethane diisocyanate component, the polyol, and the aliphatic isocyanate. All individual values and subranges from 0.5 wt% to 20 wt% are included; for example, the 1K polyurethane adhesive can include 0.5 wt%, 0.7 wt%, 1.0 wt%, or 2.0 wt% lower to 20 wt%, 18 wt%, 15 wt%, 10 wt%, 8 wt%, or 6 wt% upper of the aliphatic isocyanate, based on the total weight of the diphenylmethane diisocyanate component, the polyol, and the aliphatic isocyanate.

[0077] The aliphatic isocyanate can be used with the diphenylmethane diisocyanate component in a weight ratio of 1 :20 to 1 :5. All individual values and subranges from 1 :5 to 1 :20 are included; for example, the aliphatic isocyanate can be used with the diphenylmethane diisocyanate component in a weight ratio of a lower limit of 1 :20, 1 :18, or 1 :16 to an upper limit of 1 :5, 1 :5.5, or 1 :6.

[0078] The 1 K polyurethane adhesive disclosed herein can optionally include a quaternizing agent. Examples of quaternizing agents include, but are not limited to, alkyl halides, aralkyl halides, dialkyl carbonates, dialkyl sulfates, epoxides, and combinations thereof. Examples of particular quaternizing agents include, but are not limited to, methyl chloride, ethyl chloride, benzyl chloride, methyl bromide, ethyl bromide, benzyl bromide, dimethyl sulfate, diethyl sulfate, ethylene oxide, propylene oxide, butylene oxide, styrene oxide, epichlorohydrin, and combinations thereof. In one or more embodiments of the disclosure, the quaternizing agent is benzyl chloride.

[0079] The 1 K polyurethane adhesive disclosed herein can include 20 parts per million to 200 parts per million of the quaternizing agent, based on the total weight of the diphenylmethane diisocyanate component and the polyol. All individual values and subranges from 20 parts per million to 200 parts per million are included; for example, the 1 K polyurethane adhesive can include 20 parts per million, 30 parts per million, or 50 parts per million of a lower limit to 200 parts per million, 175 parts per million, or 150 parts per million of an upper limit of the quaternizing agent, based on the total weight of the diphenylmethane diisocyanate component and the polyol.

[0080] The 1 K polyurethane disclosed herein can include an additive. Examples of additives include, but are not limited to, organic acids, phosphoric acids, fillers, thixotropic agents, antioxidants, pigments, UV absorbers, adhesion promoters, drying agents, and combinations thereof, among others. Different amounts of the additive can be used for various applications.

[0081] The 1 K polyurethane adhesive can be prepared under conditions known for one-component moisture-curable compositions, such as mixing, combining.

[0082] The 1 K polyurethane adhesive disclosed herein can have an NCO content of 3.0 wt% to 12.0 wt%, based on the total weight of the 1 K polyurethane adhesive. All individual values and subranges from 3.0 wt% to 12.0 wt% are included; for example, the 1 K polyurethane adhesive can have an NCO content of a lower limit of 3.0 wt%, 5.0 wt%, or 7.0 wt% to an upper limit of 12.0 wt%, 11.0 wt%, or 10.0 wt%, based on the total weight of the 1 K polyurethane adhesive.

[0083] The 1K polyurethane adhesive disclosed herein may have a viscosity of 1,000 mPa·s to 6,000 mPa·s at 25°C, as determined according to ASTM D4889. This includes all individual values ​​and sub-ranges from 1,000 mPa·s to 6,000 mPa·s; for example, the 1K polyurethane adhesive may have a viscosity from a lower limit of 1,000 mPa·s, 1,250 mPa·s, or 1,500 mPa·s to an upper limit of 6,000 mPa·s, 5,000 mPa·s, or 4,500 mPa·s at 25°C, as determined according to ASTM D4889.

[0084] As described above, the 1K polyurethane adhesive disclosed herein is moisture-curable. In other words, the 1K polyurethane adhesive can be cured by exposure to water (e.g., water vapor) to form a cured product. Ambient humidity is generally sufficient to promote the curing of the 1K polyurethane adhesive. As is known in the art, the curing humidity can be adjusted to affect curing for many applications. Additionally, curing temperatures known in the art can be used. For example, in some applications, the curing temperature can be adjusted where increased curing temperature can accelerate curing.

[0085] 1K solvent-free polyurethane adhesives are commercially available, such as those branded as Voramer MR 1045L.

[0086] First and second compositions

[0087] The rubber particles in the first composition used to prepare the topcoat are EPDM particles. The rubber particles (preferably EPDM particles) in the first composition used to prepare the topcoat have an average particle size in the range of 0.1 mm to 4.5 mm, preferably 0.5 mm to 2.5 mm. The thickness of the topcoat can be 0.5 mm to 10 mm, preferably 1 mm to 5 mm, and more preferably 2 mm to 3 mm.

[0088] In the first composition used to prepare the top coating, the weight ratio of the externally emulsified polyurethane dispersion to the rubber particles (preferably EPDM particles) is 1:0.5-3, preferably 1:0.8-2, and more preferably 1:1-1.5.

[0089] According to one embodiment of this disclosure, the rubber particles in the second composition used to prepare the underlayer are EPDM particles. The rubber particles (preferably EPDM particles) in the second composition used to prepare the underlayer have an average particle size in the range of 2 mm to 10 mm, preferably 3 mm to 5 mm. The thickness of the underlayer can be 2 mm to 25 mm, preferably 5 mm to 20 mm, more preferably 8 mm to 12 mm, and even more preferably 8 mm to 10 mm.

[0090] In the second composition used to prepare the base layer, the weight ratio of 1K solvent-free polyurethane adhesive to rubber particles (preferably EPDM particles) is 1:3-12, preferably 1:6-10, and more preferably 1:7.

[0091] Auxiliaries and additives

[0092] The first and second compositions may independently and optionally contain any additional adjuvants and / or additives for a particular purpose.

[0093] In one embodiment of this disclosure, one or more of the auxiliaries and / or additives may be selected from the group consisting of: fillers, dyes / pigments, surfactants, hand feel agents, matting agents, rheology modifiers, defoamers, crosslinking agents, and stabilizers.

[0094] Any suitable rheology modifier can be used, such as those known in the art. Preferably, the rheology modifier is one that does not cause the dispersion to become unstable. More preferably, the rheology modifier is an unionized water-soluble thickener. Examples of available rheology modifiers include methylcellulose ethers, alkali-swellable thickeners (e.g., sodium or ammonium-neutralized acrylic polymers), hydrophobically modified alkali-swellable thickeners (e.g., hydrophobically modified acrylic copolymers), and associative thickeners (e.g., hydrophobically modified ethylene oxide-based urethane block copolymers). Preferably, the rheology modifier is methylcellulose ether. The amount of thickener is at least about 0.2% by weight to about 5% by weight, preferably about 0.5% by weight to about 2% by weight, of the total weight of the first or second composition.

[0095] The dye / pigment may also be referred to as a "masterbatch" in this disclosure. For example, a masterbatch may be added to impart a desired color to the layer. Examples of dyes / pigments may include iron oxide, titanium oxide, carbon black, and mixtures thereof. The amount of dye / pigment may be from 0.01% to 15% by weight, preferably from 0.5% to 10% by weight, and more preferably from 1% to 5% by weight, based on the total weight of the first or second composition.

[0096] Examples of suitable fillers include glass fibers, mineral fibers, natural fibers such as flax, jute or sisal, glass flakes, silicates such as mica or glitter, and salts such as calcium carbonate, chalk or gypsum. The filler is typically used in amounts from 0.5% to 60% by weight, preferably from 3% to 30% by weight, based on the total dry weight of the top or bottom coating.

[0097] Manufacturing techniques

[0098] The hybrid runway product of this application can be prepared by a method including the following steps:

[0099] i) applying a second composition comprising a 1K solventless polyurethane binder and rubber particles on the floor;

[0100] ii) curing the second composition to obtain a base layer;

[0101] iii) applying a first composition comprising an externally emulsified polyurethane dispersion and rubber particles, wherein the externally emulsified polyurethane dispersion is derived from: (Ai) an isocyanate component comprising one or more compounds having at least two isocyanate groups, (Bi) an isocyanate-reactive component comprising one or more compounds having at least two isocyanate-reactive groups, (Ci) an optional catalyst, (Di) an external emulsifier, (Ei) a chain extender, and (Fi) water;

[0102] iv) drying the first composition to form a topcoat layer on the base layer.

[0103] The first and second compositions can be applied by conventional coating techniques such as spraying, spreading, die coating, casting, and the like.

[0104] The second composition can be cured at RT (-20 °C to 40 °C) for one day.

[0105] The first composition can be dried at 0 °C to 40 °C under sunlight (less fog and moisture) for 1 hour - 5 hours.

[0106] The runway article of the present disclosure can also include one or more adhesive layers between the base layer and the floor. The one or more adhesive layers between the base layer and the floor can be applied by conventional coating techniques such as spraying, spreading, die coating, casting, and the like.

[0107] Examples

[0108] Some embodiments of the present application will now be described in the following examples, where all parts and percentages are by weight unless otherwise indicated.

[0109] Information of raw materials used in the examples are listed in Table 1 below:

[0110] Table 1. Raw materials

[0111]

[0112]

[0113] Preparation of prepolymers

[0114] The polyol was charged into a three necked flask and dehydrated at 110 °C for one hour under 76 mmHg pressure, then the dehydrated polyol mixture was allowed to cool naturally to 70-75 °C. IPDI was poured into the dehydrated polyol mixture at 70-75 °C under nitrogen (N2) flow protection and mechanical stirring, then the catalyst T12 was added to the reactants. The reaction was continued at 70-75 °C for one hour, then the reactants were heated to 80-85 °C for continuous reaction for 2-3 hours. The product (prepolymer) was packed with plastic bottles and stored under nitrogen protection.

[0115] Preparation of PUDs

[0116] The above prepolymer was poured into a 1000 ml plastic cup and stirred with a disperser. The SDBS aqueous solution was slowly added to the prepolymer under high speed mixing (3,800 RPM to 4,000 RPM). After mixing for a few minutes, the deionized water was added dropwise to the prepolymer under high speed mixing (3,800 RPM to 4,000 RPM). Once phase inversion occurred, the mixing speed was slowed down to no more than 1,500 RPM. At this time, an emulsion was formed. After that, the chain extender-piperazine aqueous solution was added dropwise to the emulsion. After all the chain extender solution was added, mechanical stirring was continued for another 10 to 15 minutes. Finally, a polyurethane dispersion with a solid content of about 50% was obtained and stored in a plastic container with a lid. Twelve PUDs were prepared from three prepolymer.

[0117] Details of the formulations and PUD performance are listed in Table 1.

[0118]

[0119]

[0120] Preparation of runways

[0121] 300G PUD and H18 PUD (labeled as PUD name in Table 1) were used to prepare a runway formulation.

[0122] A composition comprising 1K PU Dow Voramer MR 1045L adhesive and EPDM particles (weight ratio of PU adhesive to EPDM particles 1 to 7) was applied to a release layer (agricultural film) to form a bottom layer (0.5*0.5 m2) and cured at RT for 24 hours. After curing, the thickness of the bottom layer was 10 mm.

[0123] A formulation of PUD (50 wt% solid content), EPDM particles and color paste (both particles and color paste were provided by Zhejiang Run Sports Co., Ltd.) was sprayed by a spray machine onto the primer with a weight ratio of PUD: EPDM particles: color paste of 1 : 1 : 0.05. The spraying was performed twice. The second spraying was performed after the first spraying layer dried for 2 hours in winter, which was much faster than the 2K solventless topcoat layer (which needs overnight to cure). The thickness of the topcoat layer was 2-3 mm. Then the release layer was peeled off. The final track performance is listed in Table 3.

[0124] Table 3. Properties of PUD-based samples prepared in field trials

[0125]

[0126] According to the mechanical properties listed in Table 3, both samples have stronger tensile strength and longer elongation compared to the Chinese standard (GB / T 14833-2011) which requires tensile strength > 0.4 MPa and elongation > 40%, which means both are much better than the Chinese standard.

[0127] In addition, neither the spray method nor the PUD synthesis method uses any organic solvent, which is more environmentally friendly than the previous 2K PU spray method. Secondly, the PU resin load is also lower than 2K PU, which means lower price. Finally, the drying time of the PUD-based topcoat is very fast, about 2 hours in winter, which is much faster than the traditional 2K PU topcoat system (which can save construction time).

[0128] Determination of tensile strength and elongation at break (%)

[0129] Tensile strength and elongation at break (%) were tested according to GB / T 14833-2011.

[0130] Determination of median particle size

[0131] The median particle size of the polyurethane particles was tested by a particle size analyzer (Model: LS230, available from Beckman Coulter, INC).

[0132] Determination of viscosity

[0133] Viscosity was determined using TA Instruments AR2000ex at 25 °C or the temperature specified, with aluminum plates, continuous flow, and 1-100 S -l of shear rate.

[0134] Determination of NCO content

[0135] The NCO content (wt%) was determined by titration as follows. Toluene and a mixture of dibutylamine (DBA) (155 ml) and N,N-dimethylformamide (DMF) (350 ml) were each dried via a sieve for about 12 hours.

[0136] For sample testing, the sample to be tested was added to a container and weighed; then dried toluene (6 ml) and a dried mixture of DBA and DMF (2 ml) were added to the container, followed by isopropanol (10 ml). The contents of the container were titrated using hydrochloric acid (0.5).

[0137] The NCO content (%) was calculated by the following formula:

[0138]

[0139] where B is the volume of hydrochloric acid consumed in the blank test; S is the volume of hydrochloric acid consumed in the sample test; N is the concentration of hydrochloric acid (0.5 M), and W is the weight of the sample.

Claims

1. A hybrid runway article comprising from top to bottom: (I) a topcoat layer made from a first composition comprising an externally emulsified polyurethane dispersion and rubber particles, wherein the externally emulsified polyurethane dispersion is derived from: (Ai) an isocyanate component comprising one or more compounds having at least two isocyanate groups, (Bi) an isocyanate-reactive component comprising one or more compounds having at least two isocyanate-reactive groups, (Ci) an optional catalyst, (Di) an external emulsifier, (Ei) a chain extender, and (Fi) water, wherein the (Ei) chain extender is used in an amount to ensure a NCO closure of the prepolymer of about 70.0% to about 98.5%, wherein the prepolymer is prepared by reacting (Ai) an isocyanate component comprising one or more compounds having at least two isocyanate groups with (Bi) an isocyanate-reactive component comprising one or more compounds having at least two isocyanate-reactive groups in the presence of (Ci) an optional catalyst, and (II) a bottom layer made from a second composition comprising a 1 K solventless polyurethane binder and rubber particles.

2. The hybrid runway article according to claim 1, wherein the (Bi) isocyanate-reactive component comprising one or more compounds having at least two isocyanate-reactive groups is a polyether polyol.

3. The hybrid runway article according to claim 1, wherein the (Di) external emulsifier is selected from the group consisting of ethoxylated phenols; alkali metal fatty acid salts; alkali metal C12-C16 alkyl sulfate salts; alkali metal C12-C16 alkyl benzene sulfonate salts; anionic and non-ionic fluorocarbon emulsifiers.

4. The hybrid runway article of claim 1, wherein the (Ei) chain extender is a C4-C 15 cycloaliphatic polyamine, a C4-C 15 cycloaliphatic polyamine, or mixtures thereof.

5. The hybrid runway article according to claim 1, wherein the 1 K solventless polyurethane binder is moisture-curable.

6. The hybrid runway article according to claim 1, wherein the weight ratio of the externally emulsified polyurethane dispersion to the rubber particles is 1 : 0.5-1.

5.

7. The hybrid runway article according to claim 1 or 6, wherein the rubber particles are EPDM particles.

8. A method for preparing the hybrid runway article according to any one of claims 1 to 7, the method comprising: i) applying a second composition comprising a 1 K solventless polyurethane binder and rubber particles on a ground surface; ii) curing the second composition to obtain a bottom layer; iii) applying a first composition comprising an externally emulsified polyurethane dispersion and rubber particles, wherein the externally emulsified polyurethane dispersion is derived from: (Ai) an isocyanate component comprising one or more compounds having at least two isocyanate groups, (Bi) an isocyanate-reactive component comprising one or more compounds having at least two isocyanate-reactive groups, (Ci) an optional catalyst, (Di) an external emulsifier, (Ei) a chain extender, and (Fi) water; iv) drying the first composition to form a topcoat layer on the bottom layer.

9. Use of an externally emulsified polyurethane dispersion as a topcoat for runway articles, wherein the externally emulsified polyurethane dispersion is derived from: (Ai) an isocyanate component comprising one or more compounds having at least two isocyanate groups, (Bi) an isocyanate-reactive component comprising one or more compounds having at least two isocyanate-reactive groups, (Ci) an optional catalyst, (Di) an external emulsifier, (Ei) a chain extender, and (Fi) water, wherein the (Ei) chain extender is used in an amount to ensure a NCO blockage of the prepolymer of from about 70.0% to about 98.5%, wherein the prepolymer is prepared by reacting (Ai) an isocyanate component comprising one or more compounds having at least two isocyanate groups with (Bi) an isocyanate-reactive component comprising one or more compounds having at least two isocyanate-reactive groups in the presence of (Ci) an optional catalyst.

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