AND ROOF SYSTEM USING SAME

TECHNICAL FIELD

[0001] The present disclosure relates to a polyurethane adhesive composition having an extended workability range for adhering roofing materials to a roof substrate, and a roof system having a roof covering material adhered to a roof substrate with the extended working range polyurethane adhesive.

BACKGROUND

[0002] Various flat or low-slope roofing systems have been developed for buildings. Such flat or low-slope roofing systems commonly include a structural deck made from concrete or metal. The roofing deck is usually covered, but not exclusively, with one or more layers of insulation, and the one or more layers of insulation are covered with a waterproof membrane.

[0003] The insulation layer is commonly adhered to the underlying structural deck of the roofing system or to a vapour barrier material which is adhered on the roof deck. Adhering the insulation layer to the roof deck or the vapour barrier material is commonly accomplished by applying a suitable adhesive to the surface of the roof deck or the vapour barrier material, such as by spraying, followed by applying a plurality of individual insulation boards over the adhesive on the surface of the roof deck or the vapour barrier material to form the insulation layer.

[0004] Polyurethane adhesive compositions are commonly the adhesive of choice for adhering the insulation layer to the surface of the roof deck. It is difficult, however, to use polyurethane adhesives at low temperatures often encountered in different climatic regions of the world or during colder seasons of the year. Those having skill in the art know that the isocyanate component of the polyurethane adhesive often exhibits a sharp increase in viscosity at low temperatures, which precludes the use of a polyurethane adhesive composition at very low temperatures. SUMMARY

[0005] The inventors have surprisingly found that the modification of the isocyanate component of a polyurethane adhesive composition with selected monomers having fiexibilizing chemical structure results in a polyurethane adhesive composition having an extended workability range at temperatures down to about -15°C.

[0006] Accordingly, provided is a two-part polyurethane adhesive composition comprising the reaction product of (i) a Part A component comprising a blend of an extended workability range aliphatic and/or aromatic isocyanate pre-polymer and at least one additional isocyanate component, the Part A component having a workable viscosity of 250,000 centipoise or less at - 15°C as measured with a Brookfield Viscometer in accordance with ASTM D 2556, and is extrudable and workable in a temperature range of about -15°C to about +90°C, and (ii) a Part B component comprising at least one polyol.

[0007] Additionally provided is a method for preparing an extended workability range polyurethane adhesive composition comprising (i) blending an aliphatic and/or aromatic isocyanate pre-polymer with at least one additional isocyanate component to form a Part A component having a workable viscosity of 250,000 centipoise or less at -15°C as measured with a Brookfield Viscometer in accordance with ASTM D 2556, and is extrudable and workable in a temperature range of about -15°C to about +90°C and (ii) reacting the Part A component with a Part B component comprising at least one polyol.

[0008] According to certain illustrative embodiments, the method for preparing an extended workability range polyurethane adhesive composition comprises (i) preparing an aliphatic and/or aromatic isocyanate pre-polymer, (ii) blending the prepared aliphatic and/or aromatic isocyanate pre-polymer with at least one additional isocyanate component to form a Part A component having a workable viscosity of 250,000 centipoise or less at -15°C as measured with a Brookfield Viscometer in accordance with ASTM D 2556, and is extrudable and workable in a temperature range of about -15°C to about +90°C and (iii) reacting the with a Part B component comprising at least one polyol.

[0009] Further provided is a roof system comprising a (i) roof deck substrate and (ii) a roof covering material adhered to the roof deck substrate with (iii) an extended workability range polyurethane adhesive comprising the reaction product of (a) a Part A component comprising a blend of an aliphatic and/or aromatic isocyanate pre-polymer and at least one additional isocyanate component, the Part A component having a viscosity of 250,000 centipoise or less at -15°C as measured with a Brookfield Viscometer in accordance with ASTM D 2556, and is extrudable and workable in a temperature range of about -15°C to about +90°C and (b) a Part B component comprising at least one polyol.

[0010] According to certain illustrative embodiments, the roof system comprises a (i) roof deck substrate, (ii) at least one insulation layer adhered to the roof deck substrate with (iii) an extended workability range polyurethane adhesive comprising the reaction product of (a) a Part A component comprising a blend of an aliphatic and/or aromatic isocyanate pre-polymer and at least one additional isocyanate component, the Part A component having a viscosity of 250,000 centipoise or less at -15°C as measured with a Brookfield Viscometer in accordance with ASTM D 2556, and is extrudable and workable in a temperature range of about -15°C to about +90°C and (b) a Part B component comprising at least one polyol, and (iv) a roof covering material adhered to the insulation layer.

BRIEF DESCRIPTION OF DRAWINGS

[0011] FIG. 1 is a side view of a first illustrative embodiment of the roof system.

[0012] FIG. 2 is a side view of a second illustrative embodiment of the roof system. DETAILED DESCRIPTION

[0013] Disclosed is an extended workability range polyurethane adhesive composition.

The polyurethane adhesive composition is used for adhering roof covering materials such as insulation boards or panels and thermal barriers to a roof deck substrate. The extended workability range polyurethane adhesive composition is a two-part polyurethane adhesive composition comprising the reaction product of a Part A component and Part B component. The Part A component generally includes the one or more isocyanate components used to prepare the polyurethane adhesive. The Part B components generally include the one or more polyols that are to be reacted with the isocyanate components of the Part A component, catalysts, additives, and solvent used to prepare the polyurethane adhesive. The Part A component is mixed with the Part B component in a volume ratio of about 1 : 1 to prepare a polyurethane adhesive composition. The the Part A and B components are mixed at about 1 : 1 ratio the mixture is extrudable from a static mixer at temperatures as low at -15°C or less, and across a wide range from about -15°C to about +90°C.

[0014] The Part A component used to prepare the extended workability range polyurethane adhesive composition comprises a blend of (i) an isocyanate pre -polymer which is a reaction product of an isocyanate and a polyol having a wide variety of different chemical structures and/or equivalent weights, and (ii) at least one additional isocyanate component. The Part A component used to prepare the polyurethane adhesive composition has a viscosity of 250,000 centipoise or less, or 200,000 centipoise or less, or 150,000 centipoise or less, or 100,000 centipoise or less, or 75,000 centipoise or less at -15°C as measured with a Brookfield Viscometer in accordance with ASTM D 2556. According to certain embodiments, the Part A component used to prepare the polyurethane adhesive composition has a viscosity of 250,000 centipoise or less, or 200,000 centipoise or less, or 150,000 centipoise or less, or 100,000 centipoise or less, or 75,000 centipoise or less at -15°C as measured with a Brookfield Viscometer in accordance with ASTM D 2556 using a #7 spindle at 5 RPM. The Part A component having a low viscosity at -15°C is also remains extrudable and workable over a wide temperature range, such as, for example, from about -15°C to about +90°C. The term "blend" as used herein means that the isocyanate pre-polymer is combined or mixed together with the additional isocyanate component, but there is substantially no chemical reaction between the isocyanate pre-polymer and the additional isocyanate component. According to certain embodiments, the isocyanate pre-polymer of Part A is an NCO terminated pre-polymer. The Part B component of the extended workability range polyurethane adhesive composition comprises at least one polyol that is reactive with the reactive functionality of the isocyanate components of the Part A component. According to certain embodiments, the Part B component comprises one polyol that is reacted with the isocyanate pre-polymer and additional isocyanate components of the Part A component. According to certain embodiments, the Part B component comprises more than one polyol that are reacted with the isocyanate pre- polymer and additional isocyanate components of the Part A component.

[0015] According to certain illustrative embodiments, the Part A component used to prepare the extended workability range polyurethane adhesive composition comprises an isocyanate pre-polymer which comprises the reaction product of an isocyanate and a polyol having a poly(alkylene glycol) chemical structure and an equivalent weight ranging from 500 to 4000, and the Part B component comprises at least one polyol that is reactive with the reactive functionality of the isocyanate components of the Part A component.

[0016] According to certain illustrative embodiments, the Part A component used to prepare the extended workability range polyurethane adhesive composition comprises an isocyanate pre-polymer which comprises the reaction product of an isocyanate and a polyol having a poly(propylene glycol) chemical structure and an equivalent weight ranging from 500 to 4000, and the Part B component comprises at least one polyol that is reactive with the reactive functionality of the isocyanate components of the Part A component.

[0017] According to certain illustrative embodiments, the Part A component used to prepare the extended workability range polyurethane adhesive composition comprises an isocyanate pre-polymer which comprises the reaction product of an isocyanate and a polyol having a poly(tetrahydrofuran) chemical structure and an equivalent weight ranging from 325 to 1500, and the Part B component comprises at least one polyol that is reactive with the reactive functionality of the isocyanate components of the Part A component. [0018] According to certain illustrative embodiments, the Part A component used to prepare the extended workability range polyurethane adhesive composition comprises an isocyanate pre-polymer which comprises the reaction product of an isocyanate and a polyol having a flexible poly(butadiene) chemical structure and an equivalent weight ranging from 270 to 1650, and the Part B component comprises at least one polyol that is reactive with the reactive functionality of the isocyanate components of the Part A component.

[0019] According to certain illustrative embodiments, the Part A component used to prepare the extended workability range polyurethane adhesive composition comprises an isocyanate pre-polymer which comprises the reaction product of an isocyanate and a polyol having a flexible poly(ester) chemical structure and an equivalent weight ranging from 270 to 1650, and the Part B component comprises at least one polyol that is reactive with the reactive functionality of the isocyanate components of the Part A component.

[0020] According to certain illustrative embodiments, the Part A component used to prepare the extended workability range polyurethane adhesive composition comprises an isocyanate pre-polymer which comprises the reaction product of an isocyanate and a polyol having a poly(propylene glycol) chemical structure and equivalent weight of about 500 and about 5 to about 40% w/w of polyol of poly(butadiene) chemical structure having equivalent weights ranging from 270 to 1650, and the Part B component comprises at least one polyol that is reactive with the reactive functionality of the isocyanate components of the Part A component.

[0021] According to certain illustrative embodiments, the Part A component used to prepare the extended workability range polyurethane adhesive composition comprises an isocyanate pre-polymer which comprises the reaction product of an isocyanate and a polyol having a poly(propylene glycol) chemical structure and equivalent weight of about 500 and about 5 to about 40% w/w of polyol of poly(ester) chemical structure having equivalent weights ranging from 270 to 1650, and the Part B component comprises at least one polyol that is reactive with the reactive functionality of the isocyanate components of the Part A component. [0022] According to certain illustrative embodiments, the Part A component used to prepare the extended workability range polyurethane adhesive composition comprises a blend of an isocyanate pre-polymer which includes an isocyanate having an uretonimine-modified 4, 4' methyl diphenyl diisocyanate (4, 4' MDI) of equivalent weight 120 to 150, functionality of about 2 to about 2.2, and about 28% to about 32% free NCO, and 5 to 40% w/w of an additional isocyanate component. Without limitation, the additional isocyanate component may be selected from isophorone diisocyanate (IPDI), 4, 4 '-methylene dicyclohexyl diisocyanate (H12MDI), toluene diisocyanate (TDI), polycarbodiimide -modified diphenylmethane diisocyanate or modified hexamethylene diisocyanate, and the Part B component comprises at least one polyol that is reactive with the reactive functionality of the isocyanate components of the Part A component.

[0023] The isocyanate in the isocyanate pre-polymer may be included in amounts of about

0.5 to about 25 weight percent, about 0.5 to about 20 weight percent, about 0.5 to about 15 weight percent, about 0.5 to about 10 weight percent, about 0.5 to about 5 weight percent, and about 0.5 to about 2.5 weight percent, based on the total weight of the pre-polymer. According to other embodiments, the isocyanate in the isocyanate pre-polymer may be included in amounts of about 2.5 to about 25 weight percent, about 2.5 to about 20 weight percent, about 2.5 to about 15 weight percent, about 2.5 to about 10 weight percent, and about 2.5 to about 5 weight percent, based on the total weight of the pre-polymer. According to other embodiments, the isocyanate in the isocyanate pre-polymer may be included in in amounts of about 5 to about 25 weight percent, about 5 to about 20 weight percent, about 5 to about 15 weight percent, and about 5 to about 10 weight percent, based on the total weight of the pre-polymer. According to other embodiments, the isocyanate in the isocyanate pre-polymer may be included in amounts of about 10 to about 25 weight percent, about 10 to about 20 weight percent, and about 10 to about 15 weight percent, based on the total weight of the pre-polymer. According to other embodiments, the isocyanate in the isocyanate pre-polymer may be included in amounts of about 15 to about 25 weight percent and about 15 to about 20 weight percent, based on the total weight of the pre-polymer.

[0024] The additional isocyanate component may be included in amounts of about 5 to about 40 weight percent, about 5 to about 35 weight percent, about 5 to about 30 weight percent, about 5 to about 25 weight percent, about 5 to about 20 weight percent, about 5 to about 15 weight percent, and about 5 to about 10 weight percent, based on the total weight of the Part A components. According to other embodiments, the additional isocyanate component may be included in amounts of about 10 to about 40 weight percent, about 10 to about 35 weight percent, about 10 to about 30 weight percent, about 10 to about 25 weight percent, about 10 to about 20 weight percent, and about 10 to about 15 weight percent, based on the total weight of the Part A components. According to other embodiments, the additional isocyanate component may be included in amounts of about 15 to about 40 weight percent, about 15 to about 35 weight percent, about 15 to about 30 weight percent, about 15 to about 25 weight percent, and about 15 to about 20 weight percent, based on the total weight of the Part A components. According to other embodiments, the additional isocyanate component may be included in amounts of about 20 to about 40 weight percent, about 20 to about 35 weight percent, about 20 to about 30 weight percent, and about 20 to about 25 weight percent, based on the total weight of the Part A components. Any of the above disclosed weight percent ranges for the isocyanate pre-polymer and the additional isocyanate component can be blended together to prepared the Part A component of the polyurethane adhesive composition.

[0025] According to certain illustrative embodiments, the Part A component used to prepare the wide workability range polyurethane adhesive composition comprises a low viscosity isocyanate pre-polymer in an amount of about 5 to about 40 weight percent and an additional polymeric isocyanate component in an amount of about 60 to about 95 weight percent, based on the total weight of the Part A components.

[0026] According to certain illustrative embodiments, the Part A component used to prepare the wide workability range polyurethane adhesive composition comprises a low viscosity isocyanate pre-polymer in an amount of about 5 to about 35 weight percent and an additional polymeric isocyanate component in an amount of about 65 to about 95 weight percent, based on the total weight of the Part A components.

[0027] According to certain illustrative embodiments, the Part A component used to prepare the wide workability range polyurethane adhesive composition comprises a low viscosity isocyanate pre-polymer in an amount of about 5 to about 30 weight percent and an additional polymeric isocyanate component in an amount of about 70 to about 95 weight percent, based on the total weight of the Part A components.

[0028] According to certain illustrative embodiments, the Part A component used to prepare the wide workability range polyurethane adhesive composition comprises a low viscosity isocyanate pre-polymer in an amount of about 5 to about 25 weight percent and an additional polymeric isocyanate component in an amount of about 75 to about 95 weight percent, based on the total weight of the Part A components.

[0029] According to certain illustrative embodiments, the Part A component used to prepare the wide workability range polyurethane adhesive composition comprises a low viscosity isocyanate pre-polymer in an amount of about 5 to about 20 weight percent and an additional polymeric isocyanate component in an amount of about 80 to about 95 weight percent, based on the total weight of the Part A components.

[0030] According to certain illustrative embodiments, the Part A component used to prepare the wide workability range polyurethane adhesive composition comprises a low viscosity isocyanate pre-polymer in an amount of about 5 to about 15 weight percent and an additional polymeric isocyanate component in an amount of about 85 to about 95 weight percent, based on the total weight of the Part A components.

Isocyanate Component

[0031] The wide workability range polyurethane adhesive composition is prepared with a low viscosity aliphatic and/or aromatic isocyanate component. Useful isocyanates include compounds having at least one isocyanate (NCO) functionality. Useful low viscosity aliphatic isocyanate component include monomeric aliphatic isocyanates, aliphatic polyisocyanates, aliphatic isocyanate pre-polymers, aliphatic polyisocyanate pre-polymers, and mixtures thereof. According to certain illustrative embodiments, the low viscosity aliphatic isocyanate component comprises an aliphatic polyisocyanate pre-polymer. [0032] Aliphatic isocyanates that may be used to prepare the pre-polymer of Part A of the polyurethane adhesive composition include, for example, hexamethylene diisocyanates (HDI), hexamethylene diisocyanate trimers (HDI Trimers), dicyclohexylmethane diisocyanates (H12MDI), modified hexymethylene diisocyanates, isophorone diisocyanates (IPDI), cyclohexane diisocyanate (CHDI), tetramethylxylylene diisocyanate (TMXDI) or mixtures thereof. According to certain embodiments, the aliphatic isocyanate may be selected from the allophanate type, biuret type, or isocyanurate type. According to certain embodiments, the aliphatic isocyanate comprises an allophanate type. According to certain embodiments, the isocyanate comprises the biuret type. According to certain embodiments, the aliphatic isocyanate comprises the isocyanurate type. Without limitation, suitable commercial examples of the aliphatic isocyanates that may be used in Isonate, Lupranate, Tolonate, and Vestanat.

Additional Isocyanate Component

[0033] Any known isocyanate or blends of isocyanates typically used in the art to prepare a polyurethane adhesive may be utilized as the additional isocyanate component to prepare the wide workability range polyurethane adhesive composition so long as the desired viscosity of the total Part A component is achieved. Useful additional isocyanate components include compounds having at least two isocyanate (NCO) functionalities, such as diisocyanates, triisocyanates, tetraisocyanates, and mixtures thereof. The isocyanate may be selected from aromatic isocyanates, aliphatic isocyanates, cycloaliphatic isocyanates, araliphatic isocyanates or mixtures thereof.

[0034] Non-limiting examples of suitable aromatic isocyanates that may be used as the additional isocyanate component to prepare the polyurethane adhesive composition include methylene diphenyl diisocyanates (MDI), toluene diisocyanates (TDI), polymeric methylene diphenyl diisocyanates (PMDI), p-phenyl diisocyanates (PDI), and naphthalene diisocyanates (NDI) and mixtures thereof. [0035] Suitable polyisocyanates may include diisocyanates such as m-phenylene diisocyanate, toluene-2,4-diisocyanate, toluene-2,6-diisocyanate, mixtures of 2,4- and 2,6-toluene diisocyanate, hexamethylene-l,6-diisocyanate, tetramethylene-l,4-diisocyanate, cyclohexane- 1,4-diisocyanate, hexahydrotolylene diisocyanate (and isomers), naphthylene- 1,5 -diisocyanate, 1- methoxyphenyl-2,4-diisocyanate, diphenylmethane-4,4'-diisocyanate, diphenylmethane- 2,4'diisocyanate, diphenylmethane 2,2'diisocyanate, m-xylene diisocyanate, m- or p- tetramethylxylene diisocyanate, 4,4'dicyclohexylmethane diisocyanate, hydrogenated xylylene diisocyanate, l-methyl-2,4-diisocyanato-cyclohexane, tetramethoxybutane 1 ,4-diisocyanate, butane 1,4-diisocyanate, l,6-diisocyanato-2,2,4-trimethylhexane, tetramethoxybutane 1 ,4- diisocyanate, butane 1,4-diisocyanate, l,6-diisyanato-2,2,4-trimethylhexane, 1,6-diisocyanato- 2,4,4-trimethylhexane, l-isocyanato-l-methyl-4(3)-isocyanatomethylcyclohexane, 1,12-dodecane diisocyanate, 4,4'-biphenylene diisocyanate, 3,3'-dimethoxy-4,4'-biphenyl diisocyanate, 3,3'- dimethyl-4,4'-diisocyanate, and l-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane.

Polyol Component

[0036] Useful polyols include compounds having at least one isocyanate-reactive functionality. Any known polyol or blend of more than one polyol typically used to prepare polyurethane adhesive compositions can be used so long as the desired viscosities of the Part B component and the resulting polyurethane adhesive composition are achieved. Suitable polyols include polyether polyols, polyester polyols, polyalkylene glycols, polybutadiene polyols, low molecular weight polyols, alkylene diols and combinations thereof.

[0037] Suitable polyester polyols include, without limitation, polyesterdiol, polyestertriol, polyesterpolyol, polyesteretherdiol, polyesterethetriol, polyesteretherpolyol and mixtures thereof.

[0038] Further suitable polyester polyols include those based on caprolactone, and which are also referred to as "polycaprolactones". Further polyols which may be used are polycarbonate polyols and dimeric diols and polyols based on vegetable oils and their derivatives, such as castor oil and the derivatives thereof or epoxidized soybean oil. Also suitable are polycarbonates which have hydroxyl groups and are obtainable by reaction of carbonic acid derivatives, e.g. diphenyl carbonate, dimethyl carbonate or phosgene, with diols. For example, ethylene glycol, 1,2-and 1,3- propanediol, 1,3-and 1 ,4-butanediol, 1,6-hexanediol, 1,8-octanediol, neopentyl glycol, 1,4- bishydroxymethylcyclohexane, 2-methyl-l ,3-propanediol, 2,2,4-trimethylpentane-l ,3-diol, dipropylene glycol, polypropylene glycols, dibutylene glycol, polybutylene glycols, bisphenol A, tetrabromobisphenol A, glycerol, trimethylolpropane, 1,2,6-hexanetriol, 1,2,4-butanetriol, trimethylolpropane, pentaerythritol, quinitol, mannitol, sorbitol, methylglycoside and 1,3,4,6- dianydrohexitols are particularly suitable.

[0039] Suitable polyalkyene glycols include, without limitation, polypropylene diol, polypropylene triol, polypropylene polyol, polyethylene diol, polyethylene triol, polyethylene polyol, and mixture thereof.

[0040] Suitable poly(butadiene) polyols include poly(butadiene) diols and poly(butadiene) triols.

[0041] Suitable low molecular weight alkylene polyols include, without limitation, butanediol, hexanediol, octanediol, decanediol, dodecanediol, and mimxtures thereof.

[0042] Further suitable polyols used to form the polyurethane adhesive composition may comprise a fatty acid ester. The fatty acid ester may be at least one of natural fatty acid esters, synthetic fatty acid esters or mixtures thereof. Non-limiting examples of natural fatty acid esters include but are not limited to canola oil, castor oil, coconut oil, cotton seed oil, flax seed oil, hemp seed oil, jojoba oil, olive oil, palm oil, peanut oil, pumpkin seed oil, saffiower oil, sesame oil, soybean oil, sunflower oil, or mixtures thereof.

[0043] The NCO/OH equivalent ratio of the isocyanate pre-polymer of Part A is from about 1.5: 1 to about 5: 1. According to certain non-limiting illustrative embodiments, the NCO/OH equivalent ratio of the isocyanate pre-polymer of Part A is from about 2: 1 to about 4: 1. According to certain non-limiting illustrative embodiments, the NCO/OH equivalent ratio of the isocyanate pre-polymer of Part A is from about 2.5: 1 to about 3.5: 1. Other Additives

[0044] The low viscosity polyurethane adhesive may comprise in addition to the isocyanate and polyol components, catalysts, drying agents, plasticizers, fillers, plasticizers, chain extenders, antioxidants, fungicides, mildewcides, biocides, fire retardants, surface tension additives, coloring agents, solvents, mineral oils, thixotropic agents, dispersing agents, adhesion promoters, foaming agents, foam stabilizers, surfactants, storage stabilizers, latent hardeners, cure retarders or mixtures thereof.

[0045] Suitable filler includes a material that may be a solid and is inert to other materials in the formulation. For purposes of illustration but not by way of limitation, the filler may comprise at least one of recycled fillers, organic fibers, inorganic fibers, rubber particles, cork particles, carbon black, titanium dioxide, glass, crushed glass, glass spheres, iron particles, quartz, silica, amorphous precipitated silica, hydrophilic fumed silica, hydrophobic fumed silica, kaolin, mica, diatomaceous earth, talc, zeolites, clays, aluminum hydroxide, sulfates, aluminum sulfate, barium sulfate, calcium carbonate, dolomite, calcium sulfate, barites, limestone, wollastonite, perlite, flint powder, kryolite, alumina, alumina trihydrate, polymer granules, polymer powders, granulated or micronized polyethylene granulated or micronized polypropylene, melamine, polypropylene fibers, nylon fibers, zinc oxide, or mixtures thereof.

[0046] In certain embodiments, one or more conventional catalysts which accelerate the isocyanate-polyol reaction may be used. In certain embodiments, one or more amine catalysts may be used. For purposes of illustration but not by way of limitation, suitable amines may include triethylenediamine, dimethylethanolamine, triethanolamine, N-ethyl morpholine, N- methyldicyclohexylamine, Ν,Ν-dimethyl cycolhexylamine, N,N,N',N'-tetramethyl-l,3- butanediamine, ether and the like.

[0047] For purposes of illustration but not by way of limitation, the plasticizer may comprise adipate, azelainate, sebacate, sulfonate, trimellitate, phosphate, fumarate, or maleate ester or diester, or mixtures thereof. For illustration purposes but not by way of limitation, the plasticizer may comprise at least one of dioctyl adipate, 2-ethylhexyl adipate, diisononyl adipate, or diisodecyl adipate, di(2-ethylhexyl)azelainate, di(2-ethylhexyl)sebacate, phenyl alkylsulfonates, tri(2-ethylhexyl)trimellitate, triphenyl phosphate, tricresyl phosphate, trixylenyl phosphate, cresyl diphenyl phosphate, xylenyl diphenyl phosphate, butyl fumarate, bis(2-methylpropyl) fumarate, diisobutyl fumarate, or bis(2- ethylhexyl) fumarate, dimethyl maleate or diethyl maleate, di-(2 -propyl heptyl) phthalate or mixtures thereof.

[0048] The polyurethane adhesive composition may also comprise at least one coloring agent, such as a pigment or a dye, to provide a desired color to the formulation. Examples of colors which may be used include black, green, gray, brown and blue. In certain embodiments, the desired color is achieved by combining at least two coloring agents. The amounts of coloring agents combined may vary in any amount to obtain the desired color. Examples of coloring agents are carbon black and titanium dioxide which may be in the rutile form, but other coloring agents are also useful. Carbon black and titanium dioxide may act as both pigments and fillers in the formulation. Additional examples of pigments include, but are not limited to, barium sulfate, zinc oxide, zinc sulfide, basic lead carbonate, lithopones (zinc sulfide and barium sulfate), fluorescent dyes, oxaline dyes, inorganic color pigments such as iron oxides (e.g., iron oxide black and iron oxide brown), iron blue, carbon black, flyash, graphite, luminescent pigments, zinc yellow, zinc green, ultramarine, manganese black, antimony black, manganese violet, Paris blue, and Schweinfurter green, organic color pigments such as sepia, gamboge, Cassel brown, toluidine red, para red, Hansa yellow, indigo, azo dyes, anthraquinonoid and indigoid dyes, as well as dioxazine, quinacridone, phthalocyanine, phthalo blue, phthalo green, isoindolinone, metal complex pigments, and mixtures thereof.

[0049] Moisture scavenging molecules may be added to the composition, to ensure that the desired reaction between the isocyanate group (NCO) and the hydroxyl (OH) group takes place to form a polyurethane rather than a reaction between the isocyanate group (NCO) and water. Thus, a moisture scavenging molecule may be used to control the water level of the polyurethane prepolymer component of the composition. [0050] Moisture-sensitivity reduction additives may also be included within the composition in order to reduce the sensitivity to free water/moisture.

[0051] Adhesion promoters can also be used in the composition to enhance the adhesive properties to the roof deck substrates and insulation materials.. Examples of adhesion promoters include, but are not limited to at least one of 2-aminoethyl-dimethylmethoxysilane, 6-aminohexyl- tributoxysilane, 3-aminopropyl-trimethoxysilane, 3-aminopropyl-triethoxysilane, 3-aminopropyl- methyldimethoxysilane, 3-aminopropyl-methyldiethoxysilane, 5-aminopentyl-trimethoxysilane, 5-aminopentyl-triethoxysilane, 3-aminopropyl-triisopropoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, γ-ureidopropyltrimethoxysilane, γ-ureidopropyltriethoxysilane, 1 -[3-

(trimethoxysilyl)propyl]urea, 1 -[3-(triethoxysilyl)propyl]urea, [3 -(2- aminoethylamino)propyl]trimethoxysilane, [3-(2-minoethylamino)propyl]triethoxysilane, 2-(3,4- epoxycyclohexyl)ethyl-trimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyl-triethoxysilane, 3- (phenylamino)propyl-trimethoxysilane, 3 -(phenylamino)propyl-triethoxysilane, bis [3 - (trimethoxysilyl)propyl] amine, bis[3-(triethoxysilyl)propyl]amine, 3-mercaptopropyl- methyldimethoxysilane, 3-mercaptopropyl-methyldiethoxysilane, [3 -(2- aminoethylamino)propyl]methyl dimethoxysilane, [3-(2-aminoethylamino) propyl]methyl diethoxysilane, 3-glycidoxypropyl methyldimethoxysilane, 3-glycidoxypropyl- methyldiethoxysilane, 3-glycidyloxypropyltrimethoxy silane, or combinations thereof.

[0052] Suitable non-limiting examples of solvents that can be used to aid processing and/or as a diluent include alkyl oleates, biodiesel, aliphatic hydrocarbons such as mineral spirits, aromatic hydrocarbons such as toluene, xylene, solvent naphtha, and Aromatic 100, esters such as ethyl acetate, butyl acetate, and propylene glycol diacetate, ethers such as dipropylene glycol dimethyl ether, ketones such as methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone, and mixtures thereof.

[0053] Suitable antioxidants may be added to the adhesive formulation to improve the oxidation resistance include alkylated monophenols, alkylthiomethylphenols, hydroquinones and alkylated hydroquinones, tocopherols, hydroxylated thiodiphenyl ethers, alkylidenebisphenols, O, N- and S-benzyl compounds, hydroxybenzylated malonates, aromatic hydroxybenzyl compounds, triazine compounds, benzylphosphonates, acylaminophenols, esters of beta-(3,5-di-tert-butyl-4- hydroxyphenyl)propionic acid with mono- or polyhydric alcohols, esters of beta-(5-tert-butyl-4- hydroxy-3-methylphenyl)propionic acid with mono- or polyhydric alcohols, esters of beta-(3,5- dicyclohexyl-4-hydroxyphenyl)propionic acid with mono- or polyhydric alcohols, esters of 3,5- di-tert-butyl-4-hydroxyphenyl acetic acid with mono- or polyhydric alcohols, amides ofbeta-(3,5- di-tert-butyl-4-hydroxyphenyl)propionic acid, ascorbic acid and derivatives, aminic antioxidants, and mixtures thereof.

[0054] Suitable non-limiting examples of fungicides, mildewcides, and biocides, if used in the adhesive, may comprise, among others, 4,4-dimethyloxazolidine, 3,4,4-trimethyloxazolidine, modified barium metaborate, potassium N-hydroxy-methyl-N-methyldithiocarbamate, 2-(thiocyanomethylthio) benzothiazole, potassium dimethyl dithiocarbamate, adamantane, N- (trichloromethylthio) phthalimide, 2,4,5, 6-tetrachloroisophthalonitrile, orthophenyl phenol, 2,4,5- trichlorophenol, dehydroacetic acid, copper naphthenate, copper octoate, organic arsenic, tributyl tin oxide, zinc naphthenate, copper 8-quinolinate, and mixtures thereof.

[0055] Suitable non- limiting examples of fire retardants may be used in the adhesive composition. For purposes of illustration, but not by way of limitation, the fire retardant may include phosphates such as triphenyl phosphate, polyammonium phosphate, monoammonium phosphate, or tri(2-chloroethyl) phosphate, exfoliated graphite, acid treated natural graphite flakes, and mixtures thereof.

[0056] The polyurethane adhesive composition may further include a foam stabilization additive. According to certain embodiments, the foam stabilization additive may comprise silicone surfactant for rigid foams. Suitable non-limiting examples of the foam stabilization additive include TegoSTAG B 8951 LC, TegoSTAB B 8418, TegoSTAB B 8465 and TegoSTAB B 8580 commercially available from Evonik. Other suitable non-limiting examples of the foam stabilization additive include DC 193, DC 1605, DC 1718 and DC 2936 commercially available from Dow Corning. Further suitable non-limiting examples of the foam stabilization additive include Silstab 2000, Silstab 2100, Silstab 2965, Silstab 2985, Silstab 2300, and Silstab 2800 commercially available from Siltech Corporation.

[0057] According to certain illustrative embodiments, the roof system includes a roof substrate with or without a vapour barrier material, the wide workability range polyurethane adhesive applied to upper surface of the roof substrate or the vapour barrier material, and a roof covering applied over the wide workability range polyurethane adhesive.

[0058] The roof system comprises a roof substrate with or without a vapour barrier material, the wide workability range polyurethane adhesive applied to the upper surface of the roof substrate or the vapour barrier material, an insulation layer applied over the wide workability range polyurethane adhesive, and a roof covering layer applied over the insulation layer. The insulation layer is adhered to the upper surface of the roof deck substrate or the vapour barrier material with the polyurethane adhesive.

[0059] The roof system comprises a roof substrate with or without a vapour barrier material, the wide workability range polyurethane adhesive applied to the upper surface of the roof substrate or the vapour barrier material, more than one insulation layer applied over the wide workability range polyurethane adhesive, and a roof covering layer applied over the uppermost insulation layer. According to this embodiment, a first insulation layer is adhered to the upper surface of the roof deck substrate with the polyurethane adhesive. Additional polyurethane adhesive is applied to the upper surface of the first insulation layer, and a second insulate layer applied over and is adhered to the first insulation layer with the polyurethane adhesive. The roof covering layer is then applied over the second insulation layer.

[0060] Suitable roof substrates include, by way of example and not in limitation, wood substrates, cement board substrates, gypsum board substrate, concrete substrates, metal substrates, metal alloy substrates and composite material substrates.

[0061] Any insulation material that is typically used in roof systems of no slope or low slope roofs may be used as the insulation layer in the present roof system. Non-limiting examples of suitable insulation boards include polymeric insulation boards such as polystyrene boards and polyisocyanurate boards, and inorganic fiber based insulation boards, such as mineral wool boards.

[0062] Non-limiting examples of suitable roof covering materials include covering boards and covering membranes. According to certain illustrative embodiments, the roof covering material comprises a weather resistant membrane. Suitable non-limiting examples of roof covering membranes include ethylene propylene diene (EPDM), polyvinyl chloride (PVC), polyisbutylene (PIB), thermoplastic polyolefin (TPO) membrane, and polymer modified bituminous membranes. Suitable polymer modified bituminous membranes include SBS modified bituminous membranes, SEBS modified bituminous membranes and atatic-polypropylene (APP) modified membranes.

[0063] To construct the roof system, the polyurethane adhesive composition is applied to the upper surface of the roof deck substrate, such as a concrete or metal deck substrate or to the vapour barrier material itself adhered on the roof deck. For purposes of illustration but not by way of limitation, the polyurethane adhesive may be applied to the surface of the roof deck substrate or vapour barrier material by spraying, brushing, rolling, squeegeeing, scraping, troweling, extrusion, caulking, or combinations thereof. One method of application of the polyurethane adhesive composition is to mix the separate Part A and Part B components through a static mixer where the components begin to react, and to extrude the mixture from the end of the static mixer to the surface of the roof deck substrate or surface of insulation material (where multiple layers of insulation By way of example, an insulation layer is formed on the roof deck or vapour barrier material by applying plurality of insulation boards over the adhesive on the roof deck substrate. A waterproof or otherwise weather resistance roof covering layer is applied over the insulation layer.

[0064] According to certain embodiments, the roof system may include more than one layer of insulation material. The roof system may thus be considered to include multiple insulation layers, or an insulation layer that is comprised of multiple layers of insulation material. For embodiments that include more than one insulation material layer, the first lowermost insulation material layer that is adjacent to the roof deck substrate or vapour barrier material is adhered to the upper surface of the roof deck substrate or the vapour barrier material with a suitable amount of the wide workability range polyurethane adhesive composition. Additional polyurethane adhesive composition is applied to the upper surface of the first insulation material layer that is opposite the insulation surface that is adjacent the upper surface of the roof deck substrate. A further layer of insulation material is applied over the first insulation material layer with the polyurethane adhesive located between the layers of insulation material. The roof covering material layer is then applied over the uppermost insulation layer.

EXAMPLES

[0065] The polyurethane adhesive composition will be further described in connection with the following examples. It should be noted that the following examples are merely illustrative of certain embodiments of the polyurethane adhesive composition and the examples should not be considered to limit the scope of the claims in any manner.

[0066] Table I below shows the components of certain illustrative embodiments of Part A component of the polyurethane adhesive, and comparative examples. The pre-polymer of the Part A component is prepared by reacting the modified monomeric MDI with the polyol based on a poly(propylene glycol) chemical structure and having differing chemical, and blending the pre- polymer with polymeric MDI.

TABLE I

[0068] Table II below shows the components of certain illustrative embodiments of Part A component of the polyurethane adhesive, and comparative examples. The pre-polymer of the Part A component is prepared by reacting the modified monomeric MDI with the polyol based on a poly(tetrahydrofuran) chemical structure and having differing chemical, and blending the pre- polymer with polymeric MDI.

Table II

[0069] Table III below shows the components of certain illustrative embodiments of Part

A component of the polyurethane adhesive, and comparative examples. The pre-polymer of the Part A component is prepared by reacting the modified monomeric MDI with the polyol based on either poly(butadiene) or a polyester chemical structure and having differing chemical, and blending the pre-polymer with polymeric MDI.

TABLE III

[0070] Tables IV /V below show certain illustrative embodiments of Part A component of the polyurethane adhesive, and comparative examples. The pre-polymer of the Part A component is prepared by reacting the modified monomeric MDI with a poly(butadiene) or polyester polyol, and blending the pre-polymer with polymeric MDI. TABLE IV-A

TABLE IV-B

TABLE V-A

TABLE V-B

[0070] The roof system will now be described in greater detail with reference to the drawing figure. It should be noted that the roof system is not intended to be limited to the illustrative embodiment shown in the drawing figure.

[0071] FIG. 1 hows a side view of a non- limiting illustrative embodiment of the roof system. Roof system 10 includes a roof deck substrate 12 such as a concrete or steel deck. It may or may not also include a vapour barrier material adhered or mechanically fastened to the roof deck itself. The low viscosity polyurethane adhesive 14 is applied, typically by spraying, to the upper surface 16 of the roof deck substrate 12. An insulation layer 18 is applied over the adhesive 14, and a weather resistant membrane layer 20 is applied over the upper surface of the insulation layer 18.

[0072] FIG. 2 shows a side view of another non-limiting illustrative embodiment of the roof system. Roof system 30 includes a roof deck substrate 32 such as a concrete or steel deck. It may or may not also include a vapour barrier material adhered or mechanically fastened to the roof deck itself. The polyurethane adhesive 34 is applied to the upper surface 36 of the roof deck substrate 32. A first insulation layer 38 is applied over the adhesive 34. Additional polyurethane adhesive 40 is applied to the upper surface 42 of the first insulation layer 38. A second layer of insulation 44 is applied over the polyurethane adhesive 40. A weather resistant membrane layer 46 is applied over the upper surface of the second insulation layer 44.

[0073] While the polyurethane adhesive composition, methods of preparing the adhesive composition, roof system, and method of constructing a roof system have been described in connection with various embodiments, it is to be understood that other similar embodiments may be used or modifications and additions may be made to the described embodiments for performing the same function. Furthermore, the various illustrative embodiments may be combined to produce the desired results. Therefore, the present disclosure should not be limited to any single embodiment, but rather construed in breadth and scope in accordance with the recitation of the appended claims. It will be understood that the embodiments described herein are merely exemplary, and that one skilled in the art may make variations and modifications without departing from the spirit and scope of the invention. All such variations and modifications are intended to be included within the scope of the invention as described hereinabove. Further, all embodiments disclosed are not necessarily in the alternative, as various embodiments of the invention may be combined to provide the desired result.