Block prepolymer compositions having improved storage stability

Abstract

The present invention relates to a copolymer of one or more C hydroxyl groups, such as cardanol, in copolymerized form. 8 ~C 24 The present invention provides a blocked isocyanate prepolymer comprising a hydrocarbyl group-containing phenolic blocking agent and one or more monohydric alcohols having a normal boiling point of 110° C. or greater, such as an alkoxypoly(alkylene glycol), e.g., methoxypoly(ethylene glycol). The blocked isocyanate prepolymer exhibits surprisingly improved storage stability. The present invention further provides a method for making a blocked isocyanate prepolymer, comprising reacting a polyol with a molar excess of a polyisocyanate, blocking the resulting prepolymer, and then adding the monohydric alcohol under conditions such that the prepolymer reacts with the monohydric alcohol, e.g., at a temperature of 60° C. to 100° C.

Description

[Technical field]

[0001] The present invention relates to fluid, long chain hydrocarbyl group-containing, phenol-blocked isocyanate prepolymer compositions further comprising a monohydric alcohol in copolymerized form and having improved storage stability, and to methods for making them. More particularly, the present invention relates to a process for preparing a fluid, long chain hydrocarbyl group-containing, phenol-blocked isocyanate prepolymer composition comprising: 8 ~C 24 The present invention relates to a storage-stable fluid composition comprising a long chain hydrocarbyl group-containing phenol such as an alk(en)ylphenol, a blocked isocyanate prepolymer, and a monohydric alcohol having a boiling point of 110° C. or greater at 1 atmosphere (101.325 kPa), preferably a monohydric alcohol containing one or more ether groups, such as a methoxypoly(ethylene glycol).

[0002] Introduction Blocked isocyanate prepolymer compositions are used in many applications, such as adhesives, casting or molding materials, coatings, or thermally conductive materials for use with batteries. One drawback associated with such prepolymers arises from their poor storage stability, for example due to their tendency to gel upon storage. Furthermore, materials containing isocyanates may present issues with safe handling, such as the toxicity of resins and compositions containing them to users. To address these issues, as well as other possible health and safety requirements, such as relevant European Union (EU) regulations, isocyanate-containing compositions have been produced or modified to contain less than 0.1 wt. % of total free isocyanate monomer(s), including, for example, toluene diisocyanate (TDI) or methylene diphenyl methane diisocyanate (MDI). Blocked isocyanate prepolymers present a known method of mitigating health and safety concerns related to handling isocyanates. However, it remains desirable to provide blocked isocyanate prepolymers which have a reduced tendency to gel over time, for example between preparation and use.

[0003] More recently, the storage stability of blocked isocyanate prepolymer compositions has been enhanced by forming them while distilling the compositions used to make them. However, such distillation methods have limited usefulness and can remove reactants and / or cause undesirable side reactions, for example, when dealing with isocyanate-containing compositions such as aromatic isocyanates that boil above 100° C. at atmospheric pressure.

[0004] European Patent Publication No. EP1114854(A1) to Asahi Glass Company Ltd. discloses a reactive hot melt adhesive containing as a base a blocked urethane prepolymer produced by reacting a linear urethane prepolymer having isocyanate groups, an aliphatic monoalcohol (A) having a hydroxyl number of 200 to 560, a blocking agent (B) which is a compound other than (A), and, optionally, a low molecular weight diol having a hydroxyl number higher than 400. However, the composition mentioned by Asahi Glass has a fluid viscosity only at 110°C and does not flow at room temperature. Furthermore, the composition combines a blocking agent with an unblocked prepolymer and an aliphatic monoalcohol, which is expected to preferentially extend the prepolymer without effectively forming a blocked isocyanate prepolymer.

[0005] The present inventors have sought to provide fluid blocked isocyanate prepolymer compositions that exhibit storage stability by exhibiting acceptably small changes in viscosity upon storage, and to provide methods for their preparation. Summary of the Invention

[0006] According to the present invention, the fluid, room temperature reactive composition is 8 ~C 24The blocked isocyanate prepolymer further contains, in copolymerized form, a monohydric alcohol having a boiling point of 110°C or higher, or preferably 150°C or higher, at 1 atmosphere (101.325 kPa) and a hydroxyl value of 60 to 500. 8 ~C 24 The hydrocarbyl group-containing phenol may comprise an alkylphenol having mono-, di-, and / or triunsaturated hydrocarbyl groups, preferably a phenol having mono-, di-, or triunsaturated pentadecylene groups, or a combination of two or more thereof, such as or a combination of all three thereof, or more preferably a phenol having a mixture of mono-, di-, and triunsaturated pentadecylene groups, such as cardanol. The blocked isocyanate prepolymer comprises, in copolymerized form, a block polymer of one or more polyols, preferably one or more diols, such as one or more polyether polyols having two hydroxyl functional groups, with an excess of one or more polyisocyanates, preferably one or more aromatic diisocyanates, or more preferably toluene diisocyanate (TDI), a mixture of two TDIs, or a mixture of at least one TDI with at least one other aromatic diisocyanate. Preferably, the monohydric alcohol has one or more ether groups such as, for example, an alkoxypoly(alkylene glycol) or, more preferably, a methoxypoly(ethylene glycol) (MPEG).

[0007] The amount of monohydric alcohol in the blocked isocyanate prepolymer composition may range from 0.2 to 10% by weight, or preferably 0.5 to 5% by weight, 1 to 3% by weight, based on the total weight of all reactants used to make the blocked isocyanate prepolymer. The composition is heated at a ramp rate of 3°C / min for 10 seconds at 40°C for 10 seconds, with the composition placed between a Peltier plate having a diameter of 80 mm and a 2° cone having a diameter of 40 mm rotating at a constant angular velocity while the Peltier plate is stationary. -1When measured using a rotational rheometer performing a temperature sweep of 25 to 50 °C at a shear rate of 8 to 50 Pa s, or 10 to 40 Pa s, or preferably 12 to 33 Pa s at 25 °C and 10 s -1 The cone and plate viscosity is

[0008] Additionally, the compositions were tested for their cone and plate viscosity (25°C and 10 s) after storage at 60°C for 14 days. -1 Improved storage stability is indicated by a change in mass of 0.01 to 0.15% or less, or preferably a change in mass of 0.1 to 0.15% or less.

[0009] In another aspect of the present invention, a method for producing blocked isocyanate prepolymers having improved storage stability, such as the blocked isocyanate prepolymers of the fluid, room temperature reactive compositions according to the present invention, comprises reacting one or more polyols, preferably one or more diols, such as polyether polyols having two hydroxyl functional groups, with a molar excess of one or more polyisocyanates, preferably one or more aromatic diisocyanates, or more preferably toluene diisocyanate (TDI), a mixture of two TDIs, or a mixture of at least one TDI and at least one other aromatic diisocyanate, to produce an isocyanate-functional prepolymer; The isocyanate-functional prepolymer is 8 ~C 24 blocking with a hydrocarbyl group-containing phenol, such as an alkylphenol having mono-, di-, and / or triunsaturated hydrocarbyl groups, preferably a phenol having mono-, di-, and / or triunsaturated pentadecylene groups, or more preferably a phenol having a mixture of mono-, di-, and triunsaturated pentadecylene groups, such as cardanol, to form a blocked isocyanate prepolymer; The blocked isocyanate prepolymer is added with a monohydric alcohol having a boiling point of 110° C. or higher, or preferably 150° C. or higher, and a hydroxyl value of 60 to 500, such as C 2 dodecanol. 8 ~C 18and adding an alcohol, preferably a monohydric alcohol having one or more ether groups, such as, for example, an alkoxypoly(alkylene glycol), or more preferably, a methoxypoly(ethylene glycol) (MPEG), under conditions that allow the blocked isocyanate prepolymer and the monohydric alcohol to react with each other, for example, at a temperature of 60 to 100°C.

[0010] The process for making the blocked isocyanate prepolymer may include one or more or all of the features of the blocked isocyanate prepolymer of the present invention, including each polyol, polyisocyanate, blocking agent, monohydric alcohol, catalyst or solvent or carrier, as disclosed herein, including any copolymerized form thereof, any isocyanate prepolymer, any blocked isocyanate prepolymer, and any or all preferred or non-preferred forms thereof. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] In accordance with the present invention, compositions of isocyanate prepolymers blocked with long chain hydrocarbon-substituted phenols and further comprising a monohydric alcohol in copolymerized form in the blocked prepolymer exhibit little gelation upon storage. The inventors have found that long chain hydrocarbyl groups, such as mono-, di-, and / or triunsaturated pentadecylene groups or C 8 ~C 24 The gelation problem of blocked isocyanate prepolymers having phenolic blocking agents containing alkyl, alkenyl, alkdienyl, or alktrienyl groups has been solved. Some aromatic blocked isocyanate prepolymer compositions or the blocking agents therein solidify or gel upon storage. Phenolic blocking agents containing long chain hydrocarbyl groups do not crystallize in the blocked isocyanate prepolymers containing them. However, the inventors have discovered that such blocked isocyanate prepolymers are not storage stable.

[0012] Furthermore, the addition of a monohydric alcohol such as MPEG to the blocked isocyanate prepolymer results in more complete removal of residual isocyanate, regardless of the chemical nature of the addition. By reducing the free isocyanate content in the blocked isocyanate prepolymer and including at least one monohydric alcohol, the present inventors have discovered blocked isocyanate prepolymer compositions that have reduced viscosity and exhibit excellent storage stability and lower viscosity. Furthermore, the prepolymers of the present invention, when used in two-part thermally conductive compositions, produce cured parts with lower overall hardness.

[0013] The blocked isocyanate prepolymer composition is easily flowable and has a viscosity of 25°C and 1 sec. -1 The blocked prepolymer has a viscosity of 10-30 Pa·s at room temperature, and the viscosity does not change significantly over time at room temperature. In some cases, a decrease in the viscosity of the blocked prepolymer was also observed after adding MPEG to form the blocked isocyanate prepolymer composition of the present invention. As a result, the inventors have been able to provide a blocked isocyanate prepolymer with a relatively low viscosity in a storage stable composition. Furthermore, the composition includes a blocked prepolymer that can be crosslinked at room temperature as a two-component composition with a separate component of a primary polyamine. The resulting two-component composition has a variety of uses, and can be used to provide a cured elastomeric polyurethane suitable for use as a thermally conductive material in batteries, or as a conductive material in heat-intensive applications such as thermal management of electric vehicle batteries.

[0014] Unless otherwise indicated, temperature and pressure conditions are ambient (21-25° C.), relative humidity 35-50%, and standard pressure (1 atm or 101.325 kPa).

[0015] Unless otherwise specified, any term containing parentheses refers alternatively to the entire term as if the parentheses were present, and to the term without the parentheses, and to combinations of each alternative. Thus, as used herein, a term such as "(poly)glycol" is intended to include glycol, polyglycol, or mixtures thereof.

[0016] All recited ranges are inclusive and combinable. For example, viscosity at 25° C. and 10 seconds, measured as defined herein, ranges from 8 to 50 Pa·s, or from 10 to 40 Pa·s, or preferably from 12 to 33 Pa·s. -1 The disclosed cone and plate viscosities at include viscosity ranges of 8-50 Pa·s, or preferably 12-33 Pa·s, or 8-10 Pa·s, or 10-12 Pa·s, or 10-33 Pa·s, or 8-12 Pa·s, or 8-50 Pa·s, or 12-50 Pa·s, or 12-40 Pa·s, or 10-40 Pa·s, or 8-33 Pa·s, or 33-40 Pa·s, or 33-50 Pa·s, or 8-40 Pa·s, or 40-50 Pa·s, or 10-50 Pa·s.

[0017] As used herein, the term "ASTM" refers to publications of ASTM International, West Conshohocken, PA.

[0018] As used herein, the term "component" refers to a composition containing one or more ingredients that are combined with another component to initiate a reaction, polymerization, crosslinking, or hardening. The components remain separate until combined at the time of use or reaction.

[0019] As used herein, the term "DIN" refers to publications of the Deutsches Institut fur Normung, the German Institute for Standardization, Berlin, Germany.

[0020] As used herein, the term "ISO" refers to publications of the International Organization for Standardization, Geneva, CH.

[0021] As used herein, the term "exothermic" refers to heat evolved by a reaction that results in an increase in temperature, or at least a steadily elevated temperature (above room temperature), without the addition of any heat.

[0022] As used herein, the term "fluid" refers to a composition that flows in the absence of shear at a pressure of 1 atmosphere and a temperature of 21-25° C., e.g., a composition that readily assumes the shape of the container into which it is transported or is readily pourable.

[0023] As used herein, the term "gel" refers to a composition that does not flow or has some yield point (i.e., some applied force was required to force the gelled material to flow or move). When observed visually, a gel tends to retain its shape over time. In some cases, a gel may be a completely solidified material.

[0024] As used herein, the term "hydrocarbyl" refers to a univalent radical or substituent containing only carbon and hydrogen atoms, regardless of the presence or absence of rings or unsaturation. A "substituted hydrocarbyl group" may contain other specifically specified atoms such as oxygen or nitrogen, or specifically recited functional groups containing atoms other than carbon and hydrogen. For example, a carboxyl-containing hydrocarbyl group is a hydrocarbon radical that contains a carboxyl functionality.

[0025] As used herein, the term "hydroxyl number" expressed in mg KOH / g of analyte refers to the amount of KOH required to neutralize the acetic acid incorporated in the acetization of one gram of analyte material, as determined according to ASTM D4274. The term "average hydroxyl number" refers to the weighted average hydroxyl number of a mixture of hydroxyl-functional compounds. For example, a 50 / 50 w / w blend of a poly(ethylene glycol) having a hydroxyl number of 80 and an all-propylene oxide (PO) polyether polyol having a hydroxyl number of 60 will have an average hydroxyl functionality of 0.5(80)+0.5(60) or (40+30) or 70.

[0026] As used herein, the term "hydroxyl equivalent weight" or "equivalent weight" or "EW" of a given polyether polyol or polyol refers to a calculated value determined by the following formula: EW = 56,100 / hydroxyl number of a given polyol

[0027] As used herein, the term "condensed form" refers to the form of the material after formation of the polyurethane or isocyanate prepolymer is complete, and is not limited to the product of a condensation or addition reaction.

[0028] Unless otherwise specified, as used herein, the term "isocyanate index," or simply "index," refers to the ratio of the number of equivalents of isocyanate functional groups to the number of equivalents of hydroxyl groups in a given polyurethane or polyurethaneurea-forming reaction mixture, expressed as a number multiplied by 100. For example, in a reaction mixture in which the number of equivalents of isocyanate equals the number of equivalents of active hydrogen, the isocyanate index is 100.

[0029] As used herein, the term "isocyanate-reactive group" refers to an active hydrogen group, such as a hydroxyl group or an amine group that contains an amine hydrogen.

[0030] As used herein, the term "nominal hydroxyl functionality" refers to the number of hydroxyl groups in the ideal formula of a given diol or polyol, but not the impurities or variability in the formula, respectively. For example, the nominal hydroxyl functionality of a poly(oxyalkylene ether) or poly(ethylene glycol) is 2, and the nominal hydroxyl functionality of a glycerol-initiated polyol is the same as glycerol or is 3. When the polyol contains an alkylene oxide adduct of the initiator, the hydroxyl functionality is presumed to be equal to the functionality of the polyol initiator. The terms "nominal hydroxyl functionality" and "formula hydroxyl functionality" can be used interchangeably. The term "average hydroxyl functionality" refers to the weight average of the nominal hydroxyl functionality of a mixture of hydroxyl-functional compounds. For example, a 50 / 50 mole % mixture of ethylene glycol and glycerol has an average hydroxyl functionality of 0.5 (2 nominal OH groups in ethylene glycol) + 0.5 (3 nominal OH groups in glycerol) or (1 + 1.5) or 2.5.

[0031] As used herein, the term "molecular weight" or "MW" of a given polyether polyol or polyol refers to a calculated value determined by the following formula: MW = (56,100 / hydroxyl number) x nominal hydroxyl functionality of polyol

[0032] As used herein, the term "number average molecular weight" or "Mn" refers to the total weight of a polymer divided by the number of molecules of the polymer. Mn can be determined relative to appropriate standards using well-known methods such as gel permeation chromatography (GPC) to obtain the distribution of polymer molecular weights. The number of molecules in a sample can be estimated from the GPC data.

[0033] Unless otherwise specified, as used herein, the term "average particle size" refers to the median or median particle size of a distribution of particles as determined by laser diffraction using a Multisizer 3 Coulter Counter (Beckman Coulter, Inc., Fullerton, Calif.) following the manufacturer's recommended procedures. 50 The term "D" is defined as the size at which 50 cumulative percent of the particles in a distribution are smaller than the median diameter and 50 cumulative percent of the particles in a distribution are larger than the median diameter. 90 The term "D" refers to a size where 90 cumulative % of the particles have a size less than the stated size. 10 The term "mean particle size" refers to a size at which 10 cumulative percent of the particles have a size less than the stated size. Alternatively, the mean particle size can be estimated by measuring the composition surface area according to 8-11 ASTM D4315, or by calculating the average from the cumulative weight of each particle group using sieves of various mesh sizes. This alternative method gives an estimate of the mean particle size similar to that determined by laser diffraction methods.

[0034] As used herein, the term "polyisocyanate" refers to an isocyanate group containing material having two or more isocyanate functional groups, such as a diisocyanate, biuret, allophanate, isocyanurate, carbodiimide, dimer, trimer, or oligomer thereof, made by the reaction of an excess of isocyanate with one or more diols.

[0035] As used herein, the term "reactants used to make any polymer or prepolymer" includes all materials that react into the polymer and any catalysts that remain fugitive in the polymer, such as reactive catalysts.

[0036] As used herein, the term "storage stable" means that the composition, when left on a shelf at 60°C and atmospheric pressure for at least 14 days, does not form a gel, separate, settle, produce a visible precipitate, or give a viscosity increase of less than 20%, preferably less than 10%, over that period.

[0037] As used herein, unless otherwise specified, the term "viscosity" refers to viscosity at 25°C and 10 seconds measured using an AR2000 rotational rheometer (TA Instruments, New Castle, Del.). -1 This refers to the cone and plate viscosity at 100° C. In this measurement, the indicated material is placed between an 80 mm diameter Peltier plate (with a hardened chrome surface, TA Instruments) and a 40 mm 2° cone that rotates at a constant angular velocity while the Peltier plate is stationary, with a ramp rate of 3° C. / min, 10 s -1 Perform a temperature sweep from 25 to 50 °C at a shear rate of .

[0038] As used herein, the phrase "wt. %" stands for weight percent.

[0039] The present invention provides a fluid, storage stable composition comprising a long chain hydrocarbyl group-containing phenolic blocked isocyanate prepolymer and one or more monohydric alcohols, in copolymerized form, that do not volatilize during preparation or use of the composition. The composition may comprise a blocked isocyanate prepolymer, e.g., one or more polyols with an excess of any diisocyanate or polyisocyanate, in copolymerized form, followed by the addition of a blocking agent, such as cardanol, to form a blocked isocyanate prepolymer, followed by the addition of a monohydric alcohol, e.g., as an end-capping agent. The blocked isocyanate prepolymer may be, for example, an isocyanate prepolymer derived from an excess of an aromatic polyisocyanate and a polyether polyol, diol, or triol. The blocked isocyanate prepolymer composition has a viscosity of 8-50 Pa·s, or 10-40 Pa·s, or preferably 10-33 Pa·s, at 25°C and 10 seconds, as measured using an AR2000 rotational rheometer (TA instruments). -1 In this measurement, the indicated material is placed between an 80 mm diameter Peltier plate (with a hardened chrome surface, TA Instruments) and a 40 mm 2-degree cone that rotates at a constant angular velocity while the Peltier plate is stationary, with a ramp rate of 3°C / min, 10 s -1 A temperature sweep from 25 to 50°C is performed at a shear rate of 100 rpm with a truncation gap of 54 μm. Once the gap is reached, the analyte sample is trimmed to remove any excess material. The present invention further provides a method for making a storage stable composition comprising reacting an excess of polyisocyanate with, for example, a diol, glycol, or polyether polyol having two hydroxyl functional groups to form an isocyanate-functional prepolymer, blocking the isocyanate-functional prepolymer with a long chain hydrocarbyl group-containing phenol such as cardanol, and adding a monohydric alcohol thereto under conditions to react with the blocked isocyanate prepolymer, for example, blocking reaction conditions.

[0040] Suitable isocyanate-terminated prepolymers can be any prepolymer prepared by the reaction of one or more polyols with a stoichiometric excess of one or more polyisocyanates. The isocyanate-terminated prepolymers can be prepared by conventional methods known to those skilled in the art, for example, as disclosed in U.S. Pat. No. 4,294,951 to Sugita et al., U.S. Pat. No. 4,555,562 to Lee et al., U.S. Pat. No. 4,182,825 to Jackle, and WO 2004 / 074343 to Dow Global Technologies, Inc. The reactive materials can be mixed together and heated to promote the reaction of the polyol with the polyisocyanate. The reaction temperature can range from 30 to 150° C., such as 60 to 100° C. The reaction can be carried out in a moisture-free atmosphere. An inert gas, such as nitrogen and / or argon, can be used to blanket the reaction mixture. Additionally, an inert solvent can be used during the preparation of the isocyanate-terminated prepolymer, although the inert solvent can be omitted. A catalyst may be used to promote the formation of the urethane bond.

[0041] As used herein, the term "polyisocyanate" refers to any compound containing two or more isocyanate groups. Polyisocyanates can include diisocyanates; polymeric isocyanates, such as dimers or trimers thereof; isocyanate prepolymers, such as those formed from excess polyisocyanates reacted with one or more polyols, or mixtures thereof. Polyisocyanates can be aromatic, aliphatic, araliphatic, or cycloaliphatic polyisocyanates, or mixtures thereof, and are preferably aromatic. Polyisocyanates suitable for preparing the blocked isocyanate prepolymers of the present invention can include one or more diisocyanates, preferably aromatic diisocyanates. The polyisocyanate in the isocyanate composition can have an average isocyanate functionality of 1.9 or greater, 2.0 or greater, 2.1 or greater, 2.2 or greater, or even 2.3 or greater, and at the same time 4.0 or less, 3.8 or less, 3.5 or less, 3.2 or less, 3.0 or less, 2.8 or less, or 2.7 or less.

[0042] Such polyisocyanates for use in preparing the prepolymers of the present invention may include, for example, aromatic diisocyanates, aromatic polyisocyanates, mixtures thereof, or mixtures of two or more thereof. Examples of polyisocyanates useful according to the invention are toluene diisocyanate, toluene-2,4,6-triisocyanate, m-phenylene diisocyanate or methylene di(phenylisocyanate), diphenylmethane-4,4'-diisocyanate, diphenylmethane-2,4'-diisocyanate, hydrogenated diphenylmethane-4,4'-diisocyanate, hydrogenated diphenylmethane-2,4'-diisocyanate, toluene-2,4-diisocyanate or toluene-2,6-diisocyanate, naphthylene-1,5-diisocyanate, methoxyphenyl-2,4-diisocyanate; 4,4'-biphenylene diisocyanate, 3,3'-dimethoxy-4,4'-diphenyl diisocyanate, 3,3'-dimethyl-4,4'-bi ... ,3'-dimethyldiphenylmethane-4,4'-diisocyanate, 3,3'-dimethyldiphenylpropane-4,4'-diisocyanate, 4,4',4"-triphenylmethane triisocyanate, and 4,4'-dimethyldiphenylmethane-2,2',5,5'-tetraisocyanate, isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), tetramethylene-l,4-diisocyanate, cyclohexane-l,4-diisocyanate, hexahydrotolylene diisocyanate, 1-methoxyphenyl-2,4-diisocyanate, isomers thereof, or mixtures thereof. Toluene-2,4-diisocyanate, toluene-2,6-diisocyanate, and mixtures thereof are collectively referred to as "TDI". Diphenylmethane-4,4'-diisocyanate, diphenylmethane-2,4'-diisocyanate, and mixtures thereof are collectively referred to herein as "MDI." Particularly useful polyisocyanates can include TDI or mixtures thereof with MDI or other polyisocyanates.

[0043] Preferably, the polyisocyanate is TDI, a polymer of TDI such as its dimer or trimer, an isocyanate prepolymer, or a mixture thereof with other polyisocyanates. Toluene diisocyanate-containing prepolymers can provide lower deblocking temperatures along with ease of deblocking and reaction.

[0044] The isocyanate-terminated prepolymer produced by the method of the present invention can include a polyether backbone and an isocyanate end group. The isocyanate-terminated prepolymer can have an isocyanate content (NCO content) of 1% or more, or 2% or more, or 2.7% or more, 5% or more, 6% or more, 8% or more, or even 10% or more, and at the same time, 30% or less, 25% or less, 20% or less, or even 15% or less by weight, based on the weight of the isocyanate prepolymer. The NCO content herein is measured according to ASTM D5155-19, Test Method C (2019). The isocyanate used to prepare the isocyanate-terminated prepolymer can include any of the diisocyanates, their isomers, their polymers, their prepolymers, or mixtures thereof described above.

[0045] Suitable polyols for preparing the isocyanate-terminated prepolymer can be any polyol known in the art, including, for example, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butenediol, 1,4-butynediol, 1,5-pentanediol, neopentyl-glycol, bis(hydroxymethyl)cyclohexane, 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, polybutylene glycol, polyoxyethylene glycol, polyoxypropylene glycol, polyoxypropylene-polyoxyethylene glycol, glycerol, polyoxypropylene triol, polyoxypropylene-polyoxyethylene triol, or mixtures thereof. The functionality of suitable polyols may range from 1.9 to 3.1, the polyols may have a number average molecular weight of 500 to 10,000 or a hydroxyl number of 10 to 500 mg KOH / g, for example 20 to 200 mg KOH / g.

[0046] Polyether polyols may be prepared by adding an alkylene oxide, such as ethylene oxide (EO), propylene oxide (PO), butylene oxide (BO), or a combination thereof, to an initiator having 2 to 8 active hydrogen atoms (e.g., such that the initiator includes hydroxyl groups and excludes amines). For example, exemplary polyether polyols for prepolymer formation may include those having a number average molecular weight, in Daltons (Da), of 100 to 10,000 g / mol (Da), for example, 1000 Da or more, or 2000 Da or more, or 3,000 Da or more, or 3500 Da or more, or up to 8000 Da, or up to 6000 Da, or up to 5000 Da, or up to 4500 Da. Polyether polyols may have a functionality of 2 to 8, or at least 2, or at least 3, or up to 8, or up to 6 active hydrogen atoms per molecule.

[0047] The one or more polyether polyols may include polyoxypropylene-containing polyols, such as ethylene oxide-capped polyoxypropylene diols or triols and / or polyoxypropylene diols or triols. Exemplary polyether polyols are those available under the trade name VORANOL™ polyols (Dow Incorporated, Midland, MI (Dow)).

[0048] The preparation of polyols by alkoxylation of initiators can be carried out by procedures known in the art. For example, polyols can be made by adding alkylene oxides (EO, PO, or BO), or combinations of alkylene oxides, to initiators by anionic or cationic reactions, or by using double metal cyanide (DMC) catalysts. In some applications, only one type of alkylene oxide monomer may be used, in some other applications, a blend of monomers may be used, and in some cases, sequential addition of monomers (such as PO followed by EO feed, or EO followed by PO) may be used. In the case of copolymers, polyether polyols may be block and / or random copolymers as well as capped copolymers.

[0049] Other suitable polyols include polyester polyols, hydroxyl-terminated poly(butadiene) polyols, polyacrylate polyols, and amine-initiated polyols. Exemplary polyols with amine initiators may be autocatalytically active and are available under the trade names VORANOL™ and VORACTIV™ polyols (Dow).

[0050] Preferred polyols may be polyether polyols having two hydroxyl functional groups, such as those having a hydroxyl functionality of 1.9 to 2.2 and a number average molecular weight in the range of 1000 Da to 3000 Da.

[0051] Catalysts may be used in small amounts, for example, 0.0015 to 5 weight percent of the total weight of all reactants used to form the blocked isocyanate prepolymer. This amount depends on the catalyst or catalyst mixture and the reactivity of the polyol with the isocyanate, as well as other factors well known to those skilled in the art. Known catalysts can be used. For example, catalysts that can catalyze the isocyanate prepolymer reaction include tertiary amine catalysts and tin or metal catalysts, such as carboxylates. Examples of commercially available tertiary amine catalysts include trimethylamine, triethylamine, N-methylmorpholine, N-ethylmorpholine, N,N-dimethylbenzylamine, N,N-dimethylethanolamine, N,N-dimethylaminoethyl, N,N,N',N'-tetramethyl-1,4-butanediamine, N,N-dimethylpiperazine, 1,4-diazobicyclo-2,2,2-octane, bis(dimethylaminoethyl)ether, triethylenediamine, and dimethylalkylamines in which the alkyl group contains 4 to 18 carbon atoms. Mixtures of tertiary amine catalysts may also be used.

[0052] The blocked isocyanate prepolymer may be the reaction product of an isocyanate-terminated prepolymer, including any residual monomeric diisocyanates, with a blocking agent. To produce the blocked isocyanate prepolymer, the blocking agent may be added after or during the formation of the isocyanate prepolymer, preferably, the blocking agent is added after the formation of the isocyanate prepolymer. The blocked isocyanate prepolymer may be formed by mixing and reacting one or more isocyanates with one or more blocking agents. Suitable isocyanate blocking agents for the isocyanate-terminated prepolymer include C phenols such as hydrocarbyl-group-containing monophenols. 8 ~C 24They are aliphatic organic group substituted monophenols. For example, the isocyanate blocking groups of the isocyanate-terminated prepolymers are monophenols having at least one hydrocarbyl substituent on one or more aromatic rings. One blocking group for isocyanate-terminated prepolymers is nonylphenol.

[0053] Preferably, the blocked isocyanate prepolymer is prepared from TDI using an all-PO polyol having a number average equivalent weight of 500-3000 and a hydroxyl functionality of 1.9-3.1, and having an NCO content of 2-15 wt.% based on the total weight of the blocked isocyanate prepolymer before blocking.

[0054] Preferably, the blocking agent for the isocyanate-terminated prepolymer comprises cardanol. Cardanol is a plant-derived product derived from cashew nut shells. The cardanol-containing blocking agent may be cashew nut shell liquid (CNSL), a by-product of cashew nut processing, e.g., extracted from the layer between the nut and the shell of the cashew nut. The CNSL may have a cardanol content of at least 85% by weight, based on the total weight of the CNSL, and may further comprise less preferred cardol or methyl cardol, each having two hydroxyl groups, and / or anacardic acid as minor components. The CNSL may be subjected to a heating process, a decarboxylation process, and / or a distillation process during extraction from the cashew nut. The CNSL may comprise 85-100% by weight, or 90-99% by weight, based on the total weight of the CNSL. The CNSL may comprise less than 8.5% by weight, e.g., 0-8% by weight, 0-5% by weight, of cardol or methyl cardol, with the remainder being anacardic acid. The decarboxylated CNSL, free of anacardic acid, may be exposed to at least one distillation process.

[0055] Suitable amounts of blocking agent, expressed as the equivalent of hydroxyl groups of the blocking agent relative to the moles of isocyanate groups to be blocked, may range from 85 mol% or more, or 95 mol% or more, or preferably at least 100 mol%. A slight excess of blocking agent, for example up to 20 mol%, or up to 15 mol%, for example 5-15 mol%, or more preferably up to 10 mol% excess, based on the total moles of free isocyanate groups, i.e., isocyanate groups available for blocking, is preferred. For example, the amount of blocking agent group used for blocking may be 95 mol% to 110 mol%, based on the moles of free isocyanate groups on the prepolymer.

[0056] Suitable amounts of blocking agent may range from 1 wt% or more, or 3 wt% or more, or 5 wt% or more, or 7 wt% or more, or 9 wt% or more, or 10 wt% or more based on the total weight of the reactants used to make the blocked isocyanate prepolymer. The amount of blocking agent may be included at 10 wt% or less, or 20 wt% or less, or 40 wt% or less, or 60 wt% or less, or 80 wt% or less based on the total weight of the reactants used to make the blocked isocyanate prepolymer. Thus, the total amount of blocking agent may be included at 1 to 60 wt%, or preferably 3 to 40 wt%, or preferably 5 to 40 wt%, based on the total weight of the reactants used to make the blocked isocyanate prepolymer.

[0057] In another aspect, the present invention provides a method for making a blocked isocyanate prepolymer composition, the method comprising reacting one or more polyols with an excess of a polyisocyanate to form an isocyanate-functional prepolymer, then blocking the isocyanate-functional prepolymer with a long chain hydrocarbyl group-containing phenolic blocking agent to form a blocked isocyanate prepolymer, and then adding a monohydric alcohol to the composition under conditions to effect reaction of the blocked isocyanate prepolymer with the monohydric alcohol, e.g., at a temperature of 60-100° C. More particularly, the method comprises: reacting one or more polyols, preferably one or more diols or triols, such as polyester polyols having two or three hydroxyl functional groups, or mixtures thereof, with a molar excess of one or more polyisocyanates, preferably one or more aromatic diisocyanates, or more preferably toluene diisocyanate (TDI), a mixture of two or more TDIs, or a mixture of at least one TDI and at least one polyisocyanate, such as an aromatic diisocyanate, to produce an isocyanate-functional prepolymer; The isocyanate-functional prepolymer is 8 ~C 24 blocking with a hydrocarbyl phenol group, e.g., an alkylphenol having mono-, di-, and / or triunsaturated hydrocarbyl groups, preferably a phenol having mono-, di-, and / or triunsaturated pentadecylene groups, or more preferably a phenol having a mixture of mono-, di-, and triunsaturated pentadecylene groups, e.g., cardanol, to form a blocked isocyanate prepolymer; and adding to the blocked isocyanate prepolymer a monohydric alcohol having a boiling point of 110° C. or higher, or preferably 150° C. or higher, and a hydroxyl value of 60 to 500, preferably a monohydric alcohol having one or more ether groups, such as, for example, an alkoxypoly(alkylene glycol), or more preferably, a methoxypoly(ethylene glycol) (MPEG).

[0058] Each of forming the isocyanate prepolymer, blocking it to form the blocked isocyanate prepolymer, and adding the monohydric alcohol to the blocked isocyanate prepolymer includes combining the indicated materials to form a reaction mixture at 60-100° C., or preferably 70-97° C., for a reaction time of 2-24 hours, such as less than 12 hours to 18 hours. Each of forming the isocyanate prepolymer, blocking it, and adding the monohydric alcohol may include reacting at 60-100° C., or preferably 70-97° C., for a reaction time of 1-8 hours, such as less than 1.5 hours to 4.5 hours. Addition of the monohydric alcohol may be performed at 60-100° C., or preferably 70-97° C., for a reaction time of 1-6 hours, such as less than 1.5 hours to 4 hours. In each of the prepolymer formation and blocking, catalysts (e.g., tertiary amines), metal-containing catalysts (e.g., tin catalysts), carboxylates (e.g., mixed metal carboxylate catalysts such as zinc carboxylates and zirconium carboxylates) may be added in conventional amounts.

[0059] The blocked isocyanate prepolymers of the present invention can be used to make thermally conductive two-component compositions. Additionally, the prepolymers of the present invention can be used in other applications that utilize blocked isocyanate prepolymers, such as coatings, elastomers, adhesives, and epoxy composites.

[0060] A specific example of a composition comprising the blocked isocyanate prepolymer of the present invention may include a paste of one or more blocked isocyanate prepolymers and one or more thermally conductive fillers, such as aluminum trihydrate (ATH). The filler increases the viscosity of the paste composition, but the viscosity of the paste must be low enough to allow mixing with an amine as the curing component in a curable two-component composition, one component of which is the isocyanate component. The two components cure at 10-50°C when mixed. Suitable amines may include primary polyetheramines having a molecular weight in the range of 300 Da to 5000 Da, as determined by the hydroxyl value of the polyether used to make the polyetheramine, and a hydroxyl functionality of 2.5 to 3.5 of the polyether used to make the polyetheramine. Particularly preferred are the primary aliphatic JEFFAMINE™ series of polyetheramines (Huntsman Chemicals, Salt Lake City, UT), such as JEFFAMINE™ T-3000, and JEFFAMINE™ T-5000, JEFFAMINE™ T-403, or Baxxodur™ EC3003, Baxxodur™ EC311, Baxxodur™ EC310, available from BASF. Combinations of triamines, diamines, and monoamines can be used to tailor the cure profile and mechanical properties, such as hardness, of the final product.

[0061] The cured products of the two-component compositions have relatively low cured hardness when measured according to ASTM D2240 using a Shore OO durometer of 40 to 90 Shore OO, or 50 to 85 Shore OO, or 60 to 80 Shore OO. Such two-component compositions may find use as thermal interface materials in applications requiring the removal of heat from a heat source, such as electric vehicle batteries.

[0062] The two components of the curable composition are reactive with each other and undergo a curing reaction when contacted or mixed during application, and the reaction product of the two components is a cured product that can provide a thermally conductive interface between two surfaces. The mixture of the blocked isocyanate prepolymer composition and the amine composition can be cured at a temperature ranging from 0 to 60°C. Alternatively, the mixture of the blocked isocyanate prepolymer composition and the amine composition can be cured at a temperature ranging from 10 to 50°C. For example, the mixture of the blocked isocyanate prepolymer composition and the amine composition can be cured at a temperature ranging from 15 to 45°C. Preferably, the mixture of the blocked isocyanate prepolymer composition and the amine composition is cured at room temperature (e.g., RT) of 18 to 40°C.

[0063] Curing is indicated by an increase in viscosity after mixing the two compositions, ultimately forming a cured solid having a measurable hardness. The cured composition may have a range of cured hardness. Preferably, the cured hardness is 40-95 Shore OO, or 50-90 Shore OO, or 60-85 Shore OO, as measured according to ASTM D2240 using a Shore OO durometer.

[0064] The composition may cure in less than 14 days, or less than 10 days, or preferably less than 7 days, in more than 30 minutes. The cured composition may have a thermal conductivity greater than 0.5 Watts per meter Kelvin (W / m·K), or greater than 1 W / m·K, or most preferably greater than 1.5 W / m·K, or less than 50 W / m·K. The cured composition may have a density of 1 gm / cc to 4 gm / cc, or 1.5 to 3.5 gm / cc, or preferably 1.9 to 3.1 gm / cc.

[0065] The high thermal conductivity and low hardness make the curable composition particularly suitable for use as a gap filler for electric vehicle applications such as the assembly of energy storage devices. The curable composition can be used to transfer heat away from a heat source to a heat sink. Additionally, pre-cured thermally conductive gap pads can also be prepared from the composition. The thermal gap pads having the desired thickness are cured, cut to the desired shape, and compressed to fix in place.

[0066] The blocked isocyanate prepolymers of the present invention result in a lower hardness of the cured article, which is advantageous for gap fillers because a product with lower hardness can provide better thermal contact between the heat source and the heat sink.

[0067] In two-component compositions for use as thermal interface materials, the blocked isocyanate prepolymer component or the amine component containing one or more amines may further comprise one or more additives. Either the blocked isocyanate prepolymer composition or the amine composition may also contain one or more moisture scavengers, plasticizers, adhesion promoters, thixotropic agents, colorants, antioxidants, wetting agents, filler treatments, surface treatment additives, or combinations thereof.

[0068] The amine component includes one or more catalysts that may or may not be fugitive. Suitable catalysts may be carboxylates, tertiary amines, amidines, guanidines, diazabicyclo compounds, or combinations thereof. Fugitive catalysts include reactive groups such as active hydrogen.

[0069] The plasticizer may be mixed into either the blocked isocyanate component or the amine component in an amount of 0-20% by weight, or 2-12% by weight, or 4-10% by weight, based on the total weight of the two-component composition. Suitable plasticizers may be any common plasticizers useful in polyurethanes and known to those skilled in the art. The plasticizer may be present in an amount sufficient to disperse the prepolymer / amine or reduce the viscosity of the composition. One example of a suitable plasticizer may be a methyl ester derivative of soybean oil. Other plasticizers such as phthalates, trimethylpentanyl diisobutyrate (TXIB), or terephthalates may be used. Still other useful plasticizers may include glycol ether esters, partially hydrogenated terpenes commercially available as "HB-40" (Eastman, Kingsport, TN), chloroparaffins, alkyl naphthalenes, and the like.

[0070] Either or preferably both of the blocked isocyanate and amine components may contain at least one filler. The amount of filler may range from 40-98 wt%, or 60-95 wt%, or 75-93 wt%, or 80-92 wt% (all wt%) based on the weight of the two-component composition. Different filler sizes or fillers can be blended to obtain the desired filler loading and formulation viscosity. Preferably, the filler is alumina trihydrate (ATH). Thus, according to the present invention, a thermally conductive two-component composition can include the blocked isocyanate prepolymer composition disclosed herein in its various forms and its preferred forms, Further, the composition includes an amine composition as a separate component, and at least one of the blocked isocyanate prepolymer composition or the amine composition includes 60 to 98 weight percent of a thermally conductive filler, as measured by the total weight of the blocked isocyanate prepolymer composition or the amine composition, respectively. EXAMPLES

[0071] The following examples illustrate the invention. Unless otherwise specified, all temperatures are ambient (21-25° C.), all pressures are 1 atmosphere, and relative humidity (RH) is 35-50%. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations, the numerical values ​​set forth in the specific examples are reported as precisely as possible. Any numerical values ​​inherently contain certain errors necessarily resulting from the standard deviation found in their respective testing measurements.

[0072] Materials used in the following examples and not otherwise defined are set forth below in Table 1. Abbreviations used in the examples include the following: Da: Daltons; EO: Ethylene oxide; OHn: Hydroxyl number; NCO: Isocyanate; PO: Propylene oxide; TXIB: (2,2,4-trimethyl-1,3-pentanediol diisobutyrate).

[0073] [Table 1]

[0074] Test Methods: The following test methods were used in the examples below. Where applicable, standard deviations in all data were within acceptable limits. All applicable test results are shown in Tables 2, 3, and 4 below.

[0075] Viscosity: measured at 25°C and 10 seconds using an AR2000 rotational rheometer (TA instruments) -1 The cone and plate viscosity was measured at 100° C. for 10 seconds at 30° C. In this measurement, the indicated material was placed between a Peltier plate (80 mm diameter, with a hardened chrome surface, TA Instruments) and a 40 mm 2-degree cone with a truncated gap of 54 micrometers, rotating at a constant angular velocity while the Peltier plate was stationary, and was measured at a ramp rate of 3° C. / min, 10 seconds at 30° C. -1 Run a temperature sweep from 25 to 50 °C at a shear rate of 100 s. Once the gap was reached, the analyte sample was trimmed to remove any excess material.

[0076] Fourier transform infrared (FT-IR) spectra were measured according to attenuated total reflectance (ATR) using a Nicolet iS50 FT-IR (Thermo Fisher Scientific, Pittsburgh, PA) IR spectrometer. Approximately 15 mg of the indicated sample was transferred to the ATR and measured with a resolution of 4 cm. -1 and 16 scans were used for 4000 to 650 cm -1 Infrared spectra were collected.

[0077] The isocyanate content (NCO content) of a given composition was determined according to ASTM D5155-19, Test Method C (2019) using a Mettler DL55 (Mettler Toledo, Columbus, OH) autotitrator equipped with two titration stands, a rinse pump, a dosing pump, and an autosampler carousel. Samples were added to a solution of trichlorobenzene delivered using the rinse pump and 2N dibutylamine (in toluene) dispensed by the autotitrator using a 20 mL burette. The resulting solution was stirred for 20 minutes. The reaction mixture was then diluted with methanol, dispensed via the dosing pump, and back titrated with 1N hydrochloric acid (aqueous) using a 20 mL burette.

[0078] Storage Stability: The indicated compositions were aged in an oven at 60° C. for 2 weeks (14 days) to observe their storage stability.

[0079] Thermal conductivity was determined according to ISO 22007-2 using a Hot Disk Thermal Constants Analyzer (TPS2500S, Thermtest Instruments, Fredericton, NB, Canada). All measurements were performed with a Kapton encased thermal probe using double-sided measurements with two 6 mm cups, with a heating power of 150 mW and a measurement time of 5 seconds.

[0080] Hardness was measured using a Shore OO durometer according to ASTM D2240.

[0081] Squeeze force was measured using a TA instruments TA-XTplus texture analyzer equipped with a 50 kg load cell. After the paste was dispensed onto a flat, extremely sturdy aluminum substrate, an acrylic probe with a 40 mm diameter was lowered to pinch the test material against the flat substrate to achieve a standard gap thickness of 5.0 mm. Any excess overflow material was cut off with a flat edge spatula. After cutting, the test was started and the probe was moved at a rate of 1.0 mm / sec to a final thickness of 0.3 mm while recording the force. The specific force value recorded at the 0.5 mm gap is reported as the "squeeze force". The lower the squeeze force, the better the results.

[0082] Specific gravity was measured by measuring the sample weight in air and in water according to ASTM D792-00.

[0083] SYNTHETIC EXAMPLES: The blocked isocyanate prepolymer materials and compositions containing them tested in the following examples were prepared as follows.

[0084] Comparative Examples (CE) CE1-CE3 are all prepolymers prepared from toluene diisocyanate (TDI) and polyether diol with varying NCO content, catalyst, or process conditions. The NCO% of each prepolymer is recorded in the table.

[0085] Comparative Example 1: 35.05g of TDI was weighed into a speed mixer cup, to which 115.01g of polyether diol and 0.0155g of tin catalyst were added, mixed at 2350 RPM for 1 minute, and placed in a 70°C oven to digest the reaction for about 2 hours to form an NCO prepolymer. 110g of NCO prepolymer was weighed into a speed mixer cup, to which 0.03gm of T-9 catalyst and 53.92g of cardanol were added, then mixed at 2350 RPM for 2-3 minutes, then transferred to a dry glass jar and placed in a 80-85°C oven. The temperature was maintained at about 85°C in the oven for 4.5 hours.

[0086] Comparative Example 2: 28.35 g of TDI was added to an overhead stirrer, N 2 In and N 2 A dry 500 mL reactor equipped with an outlet, thermocouple, and heating mantle was weighed. 172 g of polyether diol (72 ppm water content) was charged and 0.0275 grams of tin catalyst (about 129 ppm) was charged. The mixture was stirred at 300-500 RPM and slowly heated to 70-75°C and the reaction was digested for about 2.0 hours to form an isocyanate prepolymer and its NCO content was measured. To the 171 g of isocyanate prepolymer in the reactor was charged the tin catalyst (0.115 g, 500 ppm) and the mixture was heated to 95°C with stirring. 41.6 grams of cardanol was charged dropwise using an addition funnel over about 15 minutes. The temperature was maintained at about 95°C for 2 hours and then additional tin catalyst (0.115 g, 500 ppm) was added and then maintained for another 2 hours.

[0087] Example 2: 207.61 g of the NCO prepolymer of Comparative Example 2 was charged with 2.21 g of MPEG (about 1 wt %) and the temperature was held at 95° C. for 2 hours.

[0088] Comparative Example 3: Overhead stirrer, N 2 In and N 2To 28.06 grams of TDI weighed in a dry 500 mL dry reactor equipped with an outlet, thermocouple, and heating mantle, was charged 172.2 g of polyether diol (water=103 ppm) and 0.0439 g of 50 wt% mixed zinc and zirconium carboxylate salt 2 in TXIB. The resulting mixture was stirred at 300-500 RPM and slowly heated to 75-80°C where the reaction was allowed to digest for approximately 2.0 hours. The reaction was stopped, cooled to 25°C, and the NCO content of the blocked isocyanate prepolymer was measured.

[0089] The reactor was heated slowly to 95°C with stirring and charged with 0.2330g of zinc and zirconium mixed carboxylate 2 catalyst. Then, 42.5g of cardanol was charged using an addition funnel, the dropwise addition was completed in about 25 minutes. The temperature was maintained at 95°C until the reaction was complete, which lasted for 2 hours. Blocking was then continued for another 2 hours with 0.2288g of additional catalyst, and the reaction was run for another 2 hours. FT-IR was taken both before and after blocking. The area count of the isocyanate peak in the FTIR can be seen in Table 3 below.

[0090] Example 3: 212.5 g of the prepolymer of Comparative Example 3 was charged with 1 wt % MPEG and the reaction was carried out at 95° C. for 1.5 hours.

[0091] Example 4: 47 g of TDI was added to an overhead stirrer, N 2 In and N 2 A dry 500 mL reactor equipped with a thermocouple, a kettle, and a heating mantle was weighed out. To this, 153 g of polyether diol was charged, followed by 0.0439 grams of 50 wt% mixed zinc and zirconium carboxylate 2 in TXIB. The mixture was stirred at 300-500 RPM and slowly heated to 75-80°C. The heated mixture was allowed to digest the reaction for approximately 2.0 hours, then the reaction was stopped and cooled to 25°C to form the NCO prepolymer. The NCO content was measured.

[0092] The isocyanate prepolymer was heated to 95°C with stirring and charged with 0.2874 grams of mixed zinc and zirconium carboxylate 2 in TXIB. To this was charged 113 grams of cardanol using an addition funnel, the dropwise addition was completed in about 25 minutes. Upon completion, the temperature had reached 95°C in 2 hours. The blocking reaction was continued with more of the same catalyst (about 500 ppm) for an additional 2 hours to form the blocked isocyanate prepolymer.

[0093] To 284 g of the prepolymer, 11.9 g of MPEG was added (about 4.2 wt %) and digested at 95° C. for 1 hour.

[0094] Example 5: 35.5 g of TDI was weighed out and placed in an overhead stirrer, N 2 In and N 2 The reaction was placed in a dry 500 mL reactor equipped with an outlet, thermocouple, and heating mantle. 115.5 g of polyether diol (water=204 ppm) and approximately 0.0202 grams of tin catalyst (approximately 134 ppm) were charged to the reactor and the mixture was stirred at 300-500 RPM while slowly heating to 70-75°C. The reaction was allowed to digest for approximately 2.25 hours. The reaction was stopped and N 2 The mixture was cooled to 25° C. under reduced pressure. The NCO content of the isocyanate prepolymer was measured.

[0095] To 113 g of isocyanate prepolymer in the reactor was added 500 ppm of tin catalyst (0.0976 g) and the mixture was heated to 95° C. with stirring. Using an addition funnel, 67.2 gm of cardanol was added, the dropwise addition was completed in about 10 minutes. The temperature was maintained at about 95° C. for 7 hours, after which 1.78 grams of MPEG (about 1 wt %) was charged and the temperature was maintained for 1 hour. After 1 hour, 0.02 g of tin catalyst was added and the reaction was maintained for 1 hour.

[0096] Example 6: 62.55 gm of TDI was added to an overhead stirrer, N 2 In and N 2A dry 500 mL reactor equipped with a thermocouple, a dry outlet, and a heating mantle was weighed. 137.75 g of polyether diol (water=68 ppm) and 0.02 grams of tin catalyst were charged to the reactor. The mixture was stirred at 300-500 RPM, slowly heated to 70-75°C, and allowed to digest for approximately 2.25 hours to form the isocyanate prepolymer. The NCO content was measured.

[0097] To 180 g of NCO prepolymer in a reactor was charged 500 ppm tin catalyst (0.1845 g) and heated to 95° C. with stirring. After heating, cardanol (170.5 g) was added using an addition funnel and the dropwise addition was completed in about 30 minutes. After the 500 ppm tin catalyst was added, the temperature was maintained at 95° C. for 2 hours to form the blocked isocyanate prepolymer. 3.4 g of MPEG was charged to the blocked isocyanate prepolymer and the temperature was held at 95° C. for 1.5 hours.

[0098] Example 7: 70.4 g of TDI was added to an overhead stirrer, N 2 In and N 2 A dry 500 mL reactor equipped with an outlet, thermocouple, and heating mantle was weighed. 80.25 gm of polyether diol (water=68 ppm) and 0.018 g of tin catalyst (about 120 ppm) were charged to the reactor. The mixture was stirred at 300-500 RPM and slowly heated to 70-75°C. The reaction was allowed to digest for about 2.25 hours to form an isocyanate prepolymer. The NCO content was then measured.

[0099] To 130.2 gm of isocyanate prepolymer in the reactor was charged 1000 ppm tin catalyst (0.404 g) and the resulting mixture was heated to 95° C. with stirring. Cardanol (209 g) was added using an addition funnel and the dropwise addition was completed in about 30 minutes. The temperature was maintained at about 95° C. for 6 hours to form the blocked isocyanate prepolymer. To this blocked isocyanate prepolymer was charged 3.45 g MPEG (about 1 wt %) and the temperature was held for 1.5 hours.

[0100] [Table 2] * -Comparative examples are shown below. 1. Undecided

[0101] As shown in Table 2 above, the compositions of Examples 2, 3, 4, 5, 6 and 7 of the present invention all showed a viscosity increase of 20% or less or a viscosity decrease upon heat aging at 60°C after 2 weeks. In contrast, the compositions of Comparative Examples 1, 2 and 3 (CE1, CE2 and CE3) that do not contain monohydric alcohol all showed a viscosity increase of at least 150% under the same aging conditions. Thus, in all the Comparative Examples, the viscosity increased significantly (even by an order of magnitude) after heat aging, indicating poor storage stability. These results clearly show that the storage stability of the blocked prepolymer is dramatically improved after the treated or capped monohydric alcohol, such as MPEG, is blocked to form a blocked isocyanate prepolymer.

[0102] Table 3 below shows the NCO FT-IR peak (2270 cm) after addition of the isocyanate prepolymer, optional cardanol blocked prepolymer, and MPEG. -1 As shown in Table 3 below, after the addition of MPEG, no peaks or very small isocyanate signals were detected by FT-IR. After the addition of MPEG, all of the prepolymers of the present invention showed an isocyanate signal at 2270 cm in FTIR. -1 The isocyanate content was estimated from an internally generated calibration curve using TDI as a benchmark. Thus, the FT-IR spectrum showed a small or undetectable NCO peak at 2269–2272 cm due to cardanol blocking. -1 They observed a reduction in the NCO peak at wavelengths of 100 nm and a further reduction when the blocked prepolymer was treated with MPEG.

[0103] [Table 3] *- Comparative examples which are intermediate products of the examples of the invention with the same numbers: 1. From the calibration curve.

[0104] Two-component curable compositions with high thermal conductivity: Examples 8A and 8B below provide curable compositions with high thermal conductivity formed with the blocked isocyanate prepolymer of the present invention. The examples demonstrate the utility of the blocked isocyanate prepolymer of Example 4 of the present invention in forming a curable two-component thermally conductive composition for use as a gap filler for EV batteries. The components shown in Table 4 below for Example 8A (blocked isocyanate composition) and Example 8B (amine composition) were mixed separately using a high speed mixer to obtain two individual thermally conductive pastes. As shown in the table below, both components individually have high thermal conductivity and low squeeze force. To measure the mixing properties, the two components were combined in a 1:1 weight ratio and mixed using a high speed mixer. As shown below, the resulting composition cured at room temperature to form a solid part with a 70-75 Shore OO hardness, high thermal conductivity (about 3 W / m·K) and low specific gravity (about 2.03 gm / cc). Such properties make this composition useful as a thermally conductive gap filler.

[0105] [Table 4]

[0106] Comparative Example 9: 64 grams (734.8 mEq.) of toluene diisocyanate (T-80 Type I) was weighed into a 500 mL oven-dried reactor and fitted with an overhead stirrer, N2 in and N2 out tubes, a thermocouple, and a heating mantle. 336 grams of polyether diol (341.54 mEq.) and 100 ppm tin catalyst catalyst (0.04 grams) were charged. The mixture was stirred at 300-500 RPM and slowly heated to 75-80°C. The mixture was allowed to digest for approximately 2.0 hours to achieve the desired NCO. Measured %NCO = 4.16.

[0107] 150 grams of 4.16% TDI prepolymer was charged to a 500 mL dry reactor and fitted with an overhead stirrer, N2 in and N2 out tubes, thermocouple, and a heating mantle. Heat with stirring to 75-80°C. Approximately 1000 ppm of Dabco 33LV catalyst and 47.0 grams of cardanol were charged. The temperature reached 80°C in approximately 10 minutes. The reaction was continued for 2 hours and the isocyanate concentration was analyzed using FT-IR. An NCO concentration of 0.41% was found using an in-house calibration curve method. A second aliquot of approximately 1000 ppm of Dabco 33LV catalyst was added and blocking was continued for an additional 3 hours. No significant decrease in the isocyanate peak was observed. Approximately 10 grams of product was released for analysis, with a calculated NCO of 0.38%.

[0108] Example 9: 190 grams of the blocked prepolymer of Comparative Example 9 was charged to a dry 500 mL reactor equipped with overhead stirring, N2 in and out tubes, thermocouple, and a heating mantle. 1.0 wt% MPEG (1.9 grams) was charged with stirring and digested at 75-80°C for 1 hour. The isocyanate concentration was found to be 0.26% by FT-IR. Blocking is considered complete. 0.5 grams of benzoyl chloride was charged. The product was discharged into a jar.

[0109] Comparative Example 10: 94 grams of toluene diisocyanate (T-80 Type I) was charged to a 500 mL oven-dried reactor and equipped with an overhead stirrer, N2 in and N2 out tubes, thermocouple, and a heating mantle. 306 grams of polyether diol and 0.04 grams of tin catalyst were charged. The mixture was stirred at 300-500 RPM and slowly heated to 75-80°C. The mixture was allowed to digest for approximately 2.0 hours to achieve the desired NCO. Measured %NCO = 8.3

[0110] 150 grams of 8.33% TDI prepolymer was charged to a 500 mL dry reactor and fitted with an overhead stirrer, N2 in and N2 out tubes, thermocouple, and a heating mantle. Heat with stirring to 75-80°C. Approximately 1000 ppm of Dabco 33LV catalyst and 94.0 grams of cardanol were charged. The temperature reached 80°C within approximately 10 minutes. The reaction was continued for 2 hours. A second aliquot of approximately 1000 ppm of Dabco 33LV catalyst was added and blocking was continued for an additional 3 hours.

[0111] Example 10: 234 grams of the block prepolymer of Comparative Example 10 was charged to a dry 500 mL reactor equipped with overhead stirring, N2 in and out tubes, thermocouple, and a heating mantle. 1.0 wt% MPEG (2.30 grams) was charged with stirring and digested at 75-80°C for 1 hour. 0.5 grams of benzoyl chloride was charged. The product was discharged into a jar.

[0112] Comparative Example 11: 124 grams of toluene diisocyanate (T-80 Type I) was charged to a 500 mL oven-dried reactor and equipped with an overhead stirrer, N2 in and N2 out tubes, thermocouple, and a heating mantle. 276 grams of polyether diol and 0.04 grams of tin catalyst were charged. The mixture was stirred at 300-500 RPM and slowly heated to 75-80°C. The mixture was allowed to digest for approximately 2.0 hours to achieve the desired NCO. Measured %NCO = 12.23.

[0113] 150 grams of 12.23% TDI prepolymer was charged to a 500 mL dry reactor and fitted with an overhead stirrer, N2 in and N2 out tubes, thermocouple, and a heating mantle. Heat with stirring to 75-80°C. Approximately 1000 ppm of Dabco 33LV catalyst and 139 grams of cardanol were charged. The temperature reached 80°C in approximately 10 minutes. The reaction was allowed to continue for 2 hours. A second aliquot of approximately 1000 ppm of Dabco 33LV catalyst was added and blocking was allowed to continue for an additional 3 hours.

[0114] Example 11: 278 grams of the block prepolymer of Comparative Example 11 was charged to a dry 500 mL reactor equipped with overhead stirring, N2 in and out tubes, thermocouple, and a heating mantle. 1.0 wt% MPEG (2.80 grams) was charged with stirring and digested at 75-80°C for 1 hour. 0.7 grams of benzoyl chloride was charged. The product was discharged into a jar.

[0115] [Table 5]

[0116] Comparative Example 12: 434.2 grams of TDI T-80 Type (I) was weighed into a dry 3 L reactor equipped with an overhead stirrer, N2 in and N2 out, thermocouple, and heating mantle. 966.3 grams of V2000LM polyol was charged and stirred for 10 minutes. Then 0.28 grams of KKAT XK604 catalyst at 50 wt% in TXIB was charged to the reactor and the mixture was stirred at 300-500 RPM and slowly heated to 75-80°C. The mixture was allowed to digest for approximately 2.0 hours to achieve the desired NCO.

[0117] 1229 grams of TDI prepolymer was charged to a 3 L dry reactor and fitted with an overhead stirrer, N2 in and N2 out, thermocouple, and heating mantle. Heat with stirring to 95°C. 0.2874 grams of 50% mixed zinc and zirconium carboxylate 2 in TXIB was charged. 1169 grams of cardanol (1.05 equiv.) was charged dropwise using an addition funnel and was completed in approximately 25-30 minutes. Upon completion, the temperature had reached 95°C. The reaction was allowed to continue for 2 hours and the isocyanate concentration was analyzed using FT-IR. An NCO concentration of 2.33% was found using an in-house calibration curve method. 500 ppm of additional mixed zinc and zirconium carboxylate 2 catalyst was charged and allowed to digest for an additional 2 hours and analyzed for isocyanate concentration using FT-IR technique. 0.57% NCO was found.

[0118] Example 12: 534 grams of the block prepolymer of Comparative Example 12 was charged into a dry 1 L reactor equipped with overhead stirring, N2 in and out, thermocouple, and heating mantle. 2.4 wt% MPEG (12.9 grams) and 100 ppm 50 wt% KKAT XK-604 catalyst (0.1068 grams) were charged with stirring and digested at 95°C for 2 hours. The isocyanate concentration was found to be 0.30% by FT-IR. The product was discharged into a jar.

[0119] Two-component curable compositions with high thermal conductivity: Example 13 and Comparative Example 13: The following Example 13 and Comparative Example 13 provide curable compositions with high thermal conductivity formed using blocked isocyanate prepolymers of the present invention. The ingredients shown in the table below for Example 13 and Comparative Example 13 were mixed separately using a high speed mixer to obtain individual thermally conductive pastes for side A and side B. The individual pastes have high thermal conductivity and low squeeze force.

[0120] The squeeze force of the individual A-side and B-side compositions of inventive Example 13 shows minimal (less than 20%) change after aging at 60° C. for 1 week, indicating that thermally conductive compositions prepared from the inventive prepolymers have good storage stability.

[0121] To measure hardness, the two components were combined in a 1:1 weight ratio, mixed using a high speed mixer, and allowed to cure at room temperature for 14 days.

[0122] The following examples show that the use of the MPEG-terminated prepolymer in Example 13 results in lower hardness of the cured parts compared to the prepolymer without MPEG in Comparative Example 13. This shows the advantage of the prepolymer of the present invention, as a product with lower hardness is preferred for gap fillers since it can provide better contact between the heat source and the heat sink.

[0123]

Table 6

Claims

1. 1. A fluid composition comprising: C ８ ~C ２４ A fluid composition comprising a hydrocarbyl group-containing phenolic blocked isocyanate prepolymer, the blocked isocyanate prepolymer having a boiling point of 110°C or higher at 1 atmosphere (101.325 kPa) and further comprising, in copolymerized form, a monohydric alcohol having a hydroxyl number of 60 to 500.

2. The C in the blocked isocyanate prepolymer ８ ~C ２４ 10. The fluid composition of claim 1, wherein the hydrocarbyl group-containing phenol comprises an alkylphenol having mono-, di-, or triunsaturated hydrocarbyl groups, or a combination of two or more thereof.

3. The C in the blocked isocyanate prepolymer ８ ~C ２４ The fluid composition of claim 2 , wherein the hydrocarbyl group-containing phenol is cardanol.

4. 10. The fluid composition of claim 1, wherein the blocked isocyanate prepolymer comprises, in copolymerized form, one or more polyols and toluene diisocyanate (TDI), a mixture of two TDIs, or a mixture of at least one TDI and at least one other aromatic diisocyanate.

5. 2. The fluid composition of claim 1, wherein the monohydric alcohol has a boiling point of 150°C or greater at 1 atmosphere (101.325 kPa).

6. The fluid composition of claim 5 wherein the monohydric alcohol is an alkoxypoly(alkylene glycol).

7. The fluid composition of claim 6, wherein the monohydric alcohol is a methoxypoly(ethylene glycol).

8. 2. The fluid composition of claim 1, wherein the amount of the monohydric alcohol in the blocked isocyanate prepolymer composition ranges from 0.2 to 10 weight percent, based on the total weight of all reactants used to make the blocked isocyanate prepolymer.

9. The composition was placed between an 80 mm diameter Peltier plate and a 40 mm 2-degree cone that rotated at a constant angular velocity while the Peltier plate was stationary, and heated at a ramp rate of 3°C / min for 10 seconds. －１ When measured using a rotational rheometer performing a temperature sweep from 25 to 50°C at a shear rate of 8 to 50 Pa s at 25°C and 10 s －１ and having a cone and plate viscosity of Furthermore, the compositions were tested for their cone and plate viscosity (at 25°C and 10 s after storage at 60°C for 14 days). －１ 10. The fluid composition of claim 1, wherein the fluid composition exhibits improved storage stability as a 20% or less change in viscosity.

10. A thermally conductive composition prepared from the fluid composition of claim 1.

11. A thermally conductive composition comprising: C further contains, in copolymerized form, a monohydric alcohol having a boiling point of 110°C or higher at 1 atmosphere (101.325 kPa) and a hydroxyl number of 60 to 500. ８ ~C ２４ a hydrocarbyl-group-containing phenol-blocked isocyanate prepolymer; A thermally conductive composition, wherein the thermally conductive composition has a thermal conductivity of greater than 0.5 W / m·K.

12. 10. A method for producing the blocked isocyanate prepolymer with improved storage stability of claim 1, comprising: reacting one or more polyols with a molar excess of one or more polyisocyanates to form an isocyanate-functional prepolymer; The isocyanate-functional prepolymer is ８ ~C ２４ blocking with a hydrocarbyl group-containing phenol; and adding a monohydric alcohol having a boiling point of 110°C or higher and a hydroxyl value of 60 to 500 to the blocked isocyanate prepolymer under conditions that allow the blocked isocyanate prepolymer and the monohydric alcohol to react with each other.