KR20240112930A - Blocked Prepolymer Compositions with Improved Storage Stability - Google Patents

Abstract

The present invention relates to one or more C ₈ to C ₂₄ hydrocarbyl group-containing phenol blocking agents, such as cardanol and one or more monohydric alcohols with a normal boiling point above 110° C., such as alkoxypoly(alkylene glycols), such as For example, provided is a blocked isocyanate prepolymer comprising methoxy poly(ethylene glycol) in copolymerized form. Blocked isocyanate prepolymers exhibit surprisingly improved storage stability. The present invention also provides a method for preparing a blocked isocyanate prepolymer, comprising reacting a polyol with a molar excess of polyisocyanate, blocking the resulting prepolymer, and then reacting the prepolymer with a monohydric alcohol. and adding the monohydric alcohol under the desired conditions, for example, at a temperature of 60 to 100° C.

Description

Blocked Prepolymer Compositions with Improved Storage Stability

The present invention relates to a fluid long-chain hydrocarbyl group-containing phenol blocked isocyanate prepolymer composition further comprising a monohydric alcohol in copolymerized form and having improved storage stability and a process for making the same. More specifically, the present invention relates to storage stable fluid compositions, which are prepared with long-chain hydrocarbyl group-containing phenols, for example C ₈ to C ₂₄ alk(en)yl phenols, with blocked isocyanate prepolymers and at 1 atm ( monohydric alcohols having a boiling point of at least 110° C. at 101.325 KPa), preferably monohydric alcohols containing at least one ether group, for example methoxypoly(ethylene glycol).

Blocked isocyanate prepolymer compositions are used in many applications, such as adhesives, casting or molding compounds, coatings, or thermal interface materials for use with batteries. One disadvantage associated with these prepolymers is due to their poor storage stability, for example due to their tendency to gel on storage. Additionally, materials containing isocyanates may pose safety handling concerns such as toxicity to users of the resin and compositions containing it. To address these issues and other possible health and safety requirements, such as relevant European Union (EU) regulations, isocyanate-containing compositions may contain less than 0.1% by weight total free isocyanate monomer(s), such as toluene diisocyanate (TDI). ) or methylene diphenylmethane diisocyanate (MDI). Blocked isocyanate prepolymers represent a well-known method of alleviating health and safety issues associated with isocyanate handling. However, it is still desirable to provide blocked isocyanate prepolymers with a reduced tendency to gel over time, eg, the time between manufacture and use.

More recently, blocked isocyanate prepolymer compositions have been made more storage stable by forming them while distilling the compositions used to prepare them. However, these distillation methods have limited utility, for example, when dealing with isocyanate-containing compositions, such as aromatic isocyanates, that boil above 100° C. at atmospheric pressure, and can eliminate reactants and/or cause undesirable side reactions.

European Patent Application Publication No. EP1114854A1 (Asahi Glass Company Ltd.) discloses a reactive hot melt adhesive, which includes a linear urethane prepolymer having an isocyanate group and an aliphatic monohydric alcohol (A) having a hydroxyl number of 200 to 560, (A) ) and, optionally, a blocked urethane prepolymer prepared by reacting a low molecular weight diol having a hydroxyl number greater than 400 as the main component. However, the composition in the Asahi Glass reference has a fluid viscosity only at 110°C and does not flow at room temperature. Additionally, the composition combines a blocking agent with an unblocked prepolymer and an aliphatic monohydric alcohol, which is expected to preferentially extend the prepolymer without effectively forming a blocked isocyanate prepolymer.

The present inventors have sought to provide blocked isocyanate prepolymer fluid compositions that exhibit storage stability by exhibiting acceptably small viscosity changes upon storage, and methods for making the same.

According to the present invention, the room temperature reactive fluid composition comprises a C ₈ to C ₂₄ hydrocarbyl group-containing phenol blocked isocyanate prepolymer, wherein the blocked isocyanate prepolymer is heated above 110° C. at 1 atm (101.325 KPa), preferably It further includes a monohydric alcohol having a boiling point of 150° C. or higher and a hydroxyl number of 60 to 500 in copolymerized form. The C ₈ to C ₂₄ hydrocarbyl group-containing phenols in the blocked isocyanate prepolymer are alkyl phenols with mono-, di- and/or tri-unsaturated hydrocarbyl groups, preferably mono-, di- or tri-unsaturated penta. phenols with decylene groups, or combinations of two or more of these, for example a phenol with a combination of all three, or more preferably, a phenol with a mixture of mono-, di- and tri-unsaturated pentadecylene groups, e.g. For example, it may include cardanol. The blocked isocyanate prepolymer comprises, in copolymerized form, one or more polyols, preferably one or more diols, for example one or more polyether polyols with two hydroxyl functions, and an excess of one or more polyisocyanates, preferably Blocked polymers of 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. Preferably, the monohydric alcohol has at least one ether group, for example an alkoxypoly(alkylene glycol), or more preferably methoxy poly(ethylene glycol) (MPEG).

The amount of monohydric alcohol in the blocked isocyanate prepolymer composition is 0.2 to 10% by weight, or preferably 0.5 to 5% by weight, based on the total weight of all reactants used to prepare the blocked isocyanate prepolymer. It may range from 1 to 3 weight percent. The composition was administered using a rotary flow meter placed between an 80 mm diameter Peltier plate and a 40 mm 2 degree cone rotating at a constant angular rate while the Peltier plate remained stationary and was flowed at a rate of 3°C/min. 8 to 50 Pa·s, or 10 ^to 40 Pa·s ^, or preferably Specifically, it may have a cone and plate viscosity ranging from 12 to 33 Pa·s. Additionally, the composition exhibits improved storage stability with a change of less than 20%, or preferably less than 10%, in cone and plate viscosity (25°C and 10 seconds ^-1 ) after 14 days of storage at 60°C.

In another aspect of the invention, the process for preparing blocked isocyanate prepolymers with improved storage stability, for example the blocked isocyanate prepolymers of room temperature reactive fluid compositions according to the invention, comprises at least one polyol, preferably one One or more diols, for example polyether polyols with two hydroxyl functional groups or mixtures thereof, are mixed with a molar excess of one or more polyisocyanates, preferably one or more aromatic diisocyanates, more preferably toluene diisocyanate (TDI), 2 preparing an isocyanate functional prepolymer by reacting a mixture of TDIs, or a mixture of at least one TDI and at least one other aromatic diisocyanate;

The isocyanate functional prepolymer can be selected from C ₈ to C ₂₄ hydrocarbyl group-containing phenols, for example alkyl phenols with mono-, di- and/or tri-unsaturated hydrocarbyl groups, preferably mono-, di-, and /or a phenol with tri-unsaturated pentadecylene groups, or more preferably a phenol with a mixture of mono-, di- and tri-unsaturated pentadecylene groups, for example by blocking with cardanol to form a blocked isocyanate prepolymer. forming step; and

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., the blocked isocyanate prepolymer has a boiling point of 110° C. or higher, or preferably 150° C. or higher and has a boiling point of 60 to 150° C. A monohydric alcohol with a hydroxyl number of 500, for example a C ₈ to C ₁₈ alcohol such as dodecanol, preferably a monohydric alcohol with at least one ether group, for example an alkoxypoly(alkylene glycol), or More preferably it includes adding methoxy poly(ethylene glycol) (MPEG).

Methods for making blocked isocyanate prepolymers include one or more or all of the features of the blocked isocyanate prepolymers of the invention disclosed herein, such as the respective polyol, polyisocyanate, blocking agent, monohydric alcohol, catalyst or solvent or carrier, For example, any of the copolymerized forms thereof, any of the isocyanate prepolymers, any of the blocked isocyanate prepolymers, and any or all preferred or non-preferred forms thereof.

According to the invention, compositions of isocyanate prepolymers blocked with a long-chain hydrocarbon substituted phenol and further comprising a monohydric alcohol in copolymerized form within the blocked prepolymer show little gelation on storage. The inventors have discovered that phenols containing long chain hydrocarbyl groups, such as mono-, di- and/or tri-unsaturated pentadecylene groups or C ₈ to C ₂₄ alkyl, alkenyl, alcdienyl or alctrienyl groups. The gelation problem of blocked isocyanate prepolymers with a sex blocker was 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 blocked isocyanate prepolymers containing them; The inventors have discovered that this blocked isocyanate prepolymer is not storage stable.

Additionally, addition of a monohydric alcohol, such as MPEG, to the blocked isocyanate prepolymer results in more complete removal of any residual isocyanate, regardless of the chemical nature of the addition. The inventors have discovered that by reducing the free isocyanate content in the blocked isocyanate prepolymer and including at least one monohydric alcohol, a blocked isocyanate prepolymer composition has reduced viscosity and exhibits excellent storage stability and lower viscosity. Additionally, the prepolymers of the present invention produce cured parts with lower overall hardness when used in two-component thermally conductive compositions.

The blocked isocyanate prepolymer composition is easy to flow and has a viscosity of 10 to 30 Pa·s at 25° C. and 1 second ⁻¹ , where the viscosity changes little over time at room temperature. In some cases, a decrease in viscosity of the blocked prepolymer was observed after adding MPEG to form the blocked isocyanate prepolymer composition of the present invention. Accordingly, the present inventors have been able to provide relatively low viscosity blocked isocyanate prepolymers in compositions that are storage stable. Additionally, the composition includes a blocked prepolymer that can be crosslinked at room temperature as a two-component composition with a separate component of primary polyamine. The resulting two-component compositions have a variety of uses, for example to provide cured elastomeric polyurethanes suitable for use as conductive materials in heat-intensive applications such as thermal interface materials in batteries or thermal management of electric vehicle batteries. can be used

Unless otherwise specified, temperature and pressure conditions are ambient temperature (21 to 25° C.), relative humidity 35 to 50%, and standard pressure (1 atm or 101.325 KPa).

Unless otherwise specified, all terms containing parentheses, alternatively, refer to the entire term as parenthesized and to a combination of the unparenthesized term and each alternative. Accordingly, as used herein, the term “(poly)glycol” and similar terms are intended to include glycols, polyglycols, or mixtures thereof.

All ranges mentioned are comprehensive and combinable. The disclosed cone at 25° C. and 10 seconds ⁻¹ measured as defined herein, for example from 8 to 50 Pa·s, or from 10 to 40 Pa·s or preferably from 12 to 33 Pa·s and The plate viscosity is 8 to 50 Pa·s, or preferably 12 to 33 Pa·s, or 8 to 10 Pa·s, or 10 to 12 Pa·s, or 10 to 33 Pa·s, or 8 to 12 Pa·s. , or 8 to 50 Pa·s, or 12 to 50 Pa·s, or 12 to 40 Pa·s, or 10 to 40 Pa·s, or 8 to 33 Pa·s, or 33 to 40 Pa·s, or 33 to 50 Pa·s, or 8 to 40 Pa·s, or 40 to 50 Pa·s, or 10 to 50 Pa·s.

As used herein, the term “ASTM” refers to a publication of ASTM International, West Conshohocken, Pa.

As used herein, the term “component” refers to a composition containing one or more components that are combined with another component to initiate a reaction, polymerization, crosslinking, or curing. The components are kept separate until combined for use or reaction.

As used herein, the term “DIN” refers to a publication of the German Institute for Standardization (Deutsches Institut fur Normung), Berlin, Germany.

As used herein, the term “ISO” refers to a publication of the International Organization for Standardization, Geneva, Switzerland.

As used herein, the term “exotherm” means heat generated by a reaction that results in an elevated or at least constant elevated temperature (above room temperature) without adding any heat.

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 to 25° C., e.g., in the form of a container into which the composition may be easily transferred or easily poured. The belt refers to the composition.

As used herein, the term “gel” refers to a composition that does not flow or has some yield point, i.e., a composition that requires the application of some force to force the flow or movement of the gelled material. When observed with the naked eye, the gel tends to maintain its shape over time. In some cases, the gel may be a completely solidified material.

As used herein, the term “hydrocarbyl” means a monovalent radical or substituent containing only carbon and hydrogen atoms, regardless of whether rings or unsaturations are present. A “substituted hydrocarbyl group” may contain other specifically identified atoms, such as oxygen or nitrogen, or a specifically listed functional group containing atoms other than carbon and hydrogen. For example, a carboxyl-containing hydrocarbyl group is a hydrocarbon radical containing a carboxyl functional group.

As used herein, the term “hydroxyl number” (mg KOH/g) of an analyte refers to the amount of KOH required to neutralize the acetic acid used in the acetylation of 1 g of analyte material as determined in accordance with ASTM D4274. it means. The term “average hydroxyl number” means the weight average of the hydroxyl number of a mixture of hydroxyl functional compounds. For example, a 50/50 w/w blend of poly(ethylene glycol) with a hydroxyl number of 80 and an all-propylene oxide (PO) polyether polyol with a hydroxyl number of 60 would yield 0.5(80) + 0.5( 60) or (40 + 30) or 70.

As used herein, the term "hydroxyl equivalent" or "equivalent weight" or "EW" of a particular polyether polyol or polyol means the calculated value determined by the equation:

EW = 56,100/hydroxyl number of specific polyol.

As used herein, the term “condensed form” refers to the form of the material after the formation of the polyurethane or isocyanate prepolymer has been completed and is not limited to the product of a condensation or addition reaction.

As used herein, unless otherwise specified, 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 particular polyurethane or polyurethane urea forming reaction mixture. It means multiplying by 100 and expressing it as a number. For example, in a reaction mixture where the number of equivalents of isocyanate is equal to the number of equivalents of active hydrogen, the isocyanate index is 100.

As used herein, the term “isocyanate reactive group” means an active hydrogen group, such as a hydroxyl group or an amine group containing an amine hydrogen.

As used herein, the term “nominal hydroxyl functionality” refers to the number of hydroxyl groups in the ideal formula of a particular diol or polyol, independent of impurities or variations in the formula. For example, the nominal hydroxyl functionality of poly(oxyalkylene ether) or poly(ethylene glycol) is 2; The nominal hydroxyl functionality of the glycerol initiated polyols is equal to or equal to glycerol. The hydroxyl functionality is assumed to be the same as that of the polyol initiator when the polyol comprises an alkylene oxide adduct of the initiator. The terms “nominal hydroxyl functionality” and “formula hydroxyl functionality” may be used interchangeably. The term “average hydroxyl functionality” means the weight average of the nominal hydroxyl functionality of a mixture of hydroxyl functional compounds. For example, a 50/50 mole percent mixture of ethylene glycol and glycerol has an average hydroxyl of 0.5 (2 nominal OH groups of ethylene glycol) + 0.5 (3 nominal OH groups of glycerol) or (1 + 1.5) or 2.5 It has functionality.

As used herein, the term “molecular weight” or “MW” of a particular polyether polyol or polyols means the calculated value determined by the following equation:

MW = (56,100/hydroxyl number)

As used herein, the term “number average molecular weight” or “Mn” means the total weight of the polymer divided by the number of molecules of the polymer. Mn can be measured using well known methods to provide a distribution of polymer molecular weight, for example using gel permeation chromatography (GPC) against an appropriate standard. The number of molecules in a sample can be estimated from GPC data.

As used herein, unless otherwise specified, the term "average particle size" refers to the term "average particle size" measured by laser diffraction using a Multisizer 3 Coulter counter (Beckman Coulter, Inc., Fullerton, CA) according to the manufacturer's recommended procedures. refers to the diameter or median particle size of the particle distribution measured by The term “median particle size” or “D ₅₀ ” is defined as the size at which cumulative 50% of the particles in a distribution are smaller than the median particle size and at which cumulative 50% of the particles in the distribution are larger than the median particle size. The term “D ₉₀ ” refers to the size at which cumulative 90% of the particles have a size less than the specified size. The term “D ₁₀ ” refers to the size at which cumulative 10% of the particles have a size less than the specified size. Alternatively, the average particle size can be estimated by measuring the surface area of the composition according to 8-11 ASTM D4315 or by using sieves of various mesh sizes and calculating the average from the cumulative weight of each size fraction. This alternative method provides estimates of average particle size similar to that measured by laser diffraction methods.

As used herein, the term “polyisocyanate” refers to a diisocyanate prepared by the reaction of an excess of isocyanate with one or more diols, or biuret, allophanate, isocyanurate, carbodiimide, dimers thereof, It refers to an isocyanate group-containing material having two or more isocyanate functional groups such as trimers or oligomers.

As used herein, the term “reactants used to prepare any polymer or prepolymer” includes all substances that react to produce the polymer, and any catalyst that remains dispersed in the polymer, such as a reactive catalyst. .

As used herein, the term "storage stability" means that the composition does not form a gel, separate, precipitate, or produce visible precipitates when left on a shelf at 60°C and atmospheric pressure for at least 14 days. It means that the viscosity increases by less than 20%, preferably less than 10%, during the period.

As used herein, and unless otherwise specified, the term "viscosity" means that the indicated material is measured against an 80 mm diameter Peltier plate (with a hardened chrome surface, TA instruments) and rotated at a constant angular velocity while the Peltier plate remains stationary. An AR2000 rotational rheometer (TA Instruments, New Castle, DE) was placed between two degree cones of 40 mm and a temperature sweep from 25 to 50 °C at a ramp rate of 3 °C/min and a shear rate of 10 s ^{-1 .} This means the cone and plate viscosity at 25°C and 10 seconds ^-1 when measured by running .

As used herein, the term “% by weight” refers to a weight percentage.

The present invention provides a storage stable fluid composition comprising a long chain hydrocarbyl group-containing phenol blocked isocyanate prepolymer and, in copolymerized form, one or more monohydric alcohols that do not volatilize during manufacture or use of the composition. The composition may comprise a blocked isocyanate prepolymer, for example, in copolymerized form, with one or more polyols and an excess of any diisocyanate or polyisocyanate, followed by the addition of a blocking agent such as cardanol to form a blocked isocyanate prepolymer. The polymer is formed and a monohydric alcohol is then added, for example as an endcapping agent. The isocyanate prepolymers to be blocked may be, for example, isocyanate prepolymers from polyether polyols, diols or triols with an excess of aromatic polyisocyanates. A blocked isocyanate prepolymer composition is obtained by placing the indicated material between an 80 mm diameter Peltier plate (with a hardened chrome surface, TA instruments) and a 40 mm 2 degree cone rotating at a constant angular velocity while the Peltier plate remains stationary. 25° ^C and It has a cone and plate viscosity of 8 to 50 Pa·s, or 10 to 40 Pa·s, or preferably 10 to 33 Pa·s at 10 seconds ^-1 . Once the gap was reached, the analyte sample was trimmed to remove any excess material. The present invention also provides a method of preparing storage stable compositions, which comprises reacting an excess polyisocyanate with, for example, a diol, glycol or polyether polyol having two hydroxyl functional groups to form an isocyanate functional prepolymer. Step, blocking the isocyanate functional prepolymer with a long chain hydrocarbyl group-containing phenol such as cardanol, and under conditions allowing the blocked isocyanate prepolymer to react with the monohydric alcohol, for example under blocking reaction conditions, wherein It includes adding a monohydric alcohol to.

A suitable isocyanate-terminated prepolymer may be any prepolymer(s) prepared by reaction of one or more polyols with a stoichiometric excess of one or more polyisocyanates. Isocyanate-terminated prepolymers can be prepared by conventional methods known to those skilled in the art, for example, in US Pat. Nos. 4,294,951 to Sugita et al., US Pat. Nos. 4,555,562 to Lee et al., and US Pat. and Dow Global Technologies, Inc., International Publication No. WO 2004/074343. The reactive materials can be mixed together and heated to promote the reaction of the polyol and polyisocyanate. The reaction temperature may range from 30 to 150°C, for example from 60 to 100°C. The reaction can be carried out in a moisture-free atmosphere. Inert gases, such as nitrogen and/or argon, can be used to permeate the reaction mixture. Additionally, inert solvents may be used during the preparation of the isocyanate-terminated prepolymer, but inert solvents may also be excluded. Catalysts that promote urethane bond formation may also be used.

As used herein, the term “polyisocyanate” means any compound containing two or more isocyanate groups. Polyisocyanates include diisocyanates; polymeric isocyanates, such as dimers or trimers thereof; Isocyanate prepolymers, such as those formed from an excess of polyisocyanate reacted with one or more polyols or mixtures thereof. The polyisocyanate may be aromatic, aliphatic, araliphatic, or cycloaliphatic polyisocyanate, or mixtures thereof, preferably aromatic. Polyisocyanates suitable for preparing the blocked isocyanate prepolymers of the present invention may comprise one or more diisocyanates, preferably aromatic diisocyanates. The polyisocyanate in the isocyanate composition may have an average isocyanate of at least 1.9, at least 2.0, at least 2.1, at least 2.2, or even at least 2.3, and simultaneously at most 4.0, at most 3.8, at most 3.5, at most 3.2, at most 3.0, at most 2.8, or at most 2.7. It can have functionality.

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(phenyl isocyanate), 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'-biphenyl diisocyanate, 3,3'- Dimethyldiphenylmethane-4,4'-diisocyanate, 3,3'-dimethyldiphenylpropane-4,4'-diisocyanate, 4,4',4"-triphenyl methane triisocyanate, and 4,4' -Dimethyldiphenylmethane-2,2',5,5'-tetriisocyanate, isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), tetramethylene-1,4-diisocyanate, cyclohexane-1, It may include one or more of 4-diisocyanate, hexahydrotolylene diisocyanate, 1-methoxyphenyl-2,4-diisocyanate, isomers thereof, or mixtures thereof. , toluene-2,6-diisocyanate and mixtures thereof are commonly referred to as "TDI" diphenylmethane-4,4'-diisocyanate, diphenylmethane-2,4'-diisocyanate and mixtures thereof. Particularly useful polyisocyanates, generally referred to herein as “MDI,” may include TDI, or mixtures thereof with MDI or other polyisocyanates.

Preferably, the polyisocyanate is TDI, a polymer of TDI, for example dimers or trimers thereof, isocyanate prepolymers thereof, or mixtures of these with other polyisocyanates. Toluene diisocyanate containing prepolymers can lead to lower deblocking temperatures along with ease of deblocking and reaction.

Isocyanate-terminated prepolymers prepared by the process of the present invention may include a polyether backbone and isocyanate end groups. The isocyanate-terminated prepolymer may have at least 1% by weight, or at least 2% by weight, or at least 2.7% by weight, at least 5% by weight, at least 6% by weight, at least 8% by weight, or even by weight, based on the weight of the isocyanate prepolymer. It may have an isocyanate content (NCO content) of at least 10% by weight, and at the same time at most 30% by weight, at most 25% by weight, at most 20% by weight, or even at most 15% by weight. Herein, the NCO content is measured according to ASTM D5155-19, Test Method C (2019). The isocyanate used to prepare the isocyanate-terminated prepolymer may include any of the diisocyanates described above, their isomers, their polymers, their prepolymers, or mixtures thereof.

Polyols suitable for preparing isocyanate-terminated prepolymers include, for example, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butenediol, 1,4-butyne. Diols, 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 -It can be any polyol known in the art, including 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 polyol 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.

Polyether polyols are alkylene oxides, such as ethylene oxide (EO), propylene oxide (PO), butylene oxide (BO), or combinations thereof, with an initiator having 2 to 8 active hydrogen atoms (e.g. It can be prepared by adding a hydroxyl group and excluding an amine). For example, exemplary polyether polyols for forming prepolymers have a molecular weight of 100 to 10000 g/mol (Da), such as at least 1000 Da, or at least 2000 Da, or at least 3,000 Da, or at least 3500 Da, or up to 8000 Da. Da, or up to 6000 Da, or up to 5000 Da, or up to 4500 Da. The polyether polyol may have 2 to 8, or at least 2, or at least 3, or up to 8, or up to 6 active hydrogen atoms per molecule.

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, Mich.).

Preparation of polyols by alkoxylation of initiators can be carried out by procedures known in the art. For example, polyols are prepared by addition of alkylene oxides (EO, PO or BO), or combinations of alkylene oxides, to an initiator via anionic or cationic reactions or the use of double metal cyanide (DMC) catalysts. It can be. In some applications, only one alkylene oxide monomer may be used; In some other applications combinations of monomers may be used, and in some cases sequential addition of monomers may be used, for example PO and then EO feed or EO and then PO. In the case of copolymers, the polyether polyols can be block and/or random copolymers as well as capped copolymers.

Other suitable polyols include polyester polyols, hydroxyl-terminated poly(butadiene) polyols, polyacrylate polyols, and amine initiated polyols. Exemplary polyols with amine initiators can have their own catalytic activity and are available under the trade names VORANOL™ and VORACTIV™ polyols (Dow).

Preferred polyols may be polyether polyols with two hydroxyl functional groups, for example those with a hydroxyl functionality of 1.9 to 2.2 and a number average molecular weight in the range of 1000 Da to 3000 Da.

The catalyst may be used in small amounts, for example, 0.0015 to 5% by weight of the total weight of all reactants used to form the blocked isocyanate prepolymer. The amount depends on the catalyst or mixture of catalysts and the reactivity of the polyol with the isocyanate as well as other factors familiar to those skilled in the art. Known catalysts can be used. For example, catalysts capable of catalyzing 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 dimethylalkylamine, where the alkyl group contains 4 to 18 carbon atoms. Mixtures of tertiary amine catalysts may be used.

The blocked isocyanate prepolymer may be the reaction product of a blocking agent and an isocyanate-terminated prepolymer containing any residual monomeric diisocyanate. To prepare the blocked isocyanate prepolymer, the blocking agent can be added after or during the isocyanate prepolymer formation; preferably, the blocking agent is added after the isocyanate prepolymer formation and the blocked isocyanate prepolymer is added during the isocyanate prepolymer formation. It can be formed by mixing and reacting one or more with one or more blocking agents. Suitable isocyanate blocking agents for isocyanate-terminated prepolymers are monophenols substituted with C ₈ to C ₂₄ aliphatic organic groups, for example hydrocarbyl group-containing monophenols. For example, the isocyanate blocking group for the isocyanate-terminated prepolymer is a monophenol having at least one hydrocarbyl substituent on one or more aromatic ring(s). One of the blocking groups for isocyanate-terminated prepolymers is nonylphenol.

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

Preferably, the blocking agent for the isocyanate-terminated prepolymer includes 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, for example, 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 include less preferred cardol or methylcardol, each of which has two hydroxyl groups, and/or It has anacardic acid as a secondary component. CNSL may undergo a heating process during extraction from cashew nuts, a decarboxylation process and/or a distillation process. The CNSL may include 85 to 100% by weight, or 90 to 99% by weight, cardanol, based on the total weight of the CNSL. The CNSL may comprise less than 8.5% by weight, for example 0 to 8%, 0 to 5% by weight, of cardol or methylcardol, with the remainder being anacardic acid. The decarboxylated CNSL containing no anacardic acid may be exposed to at least one distillation process.

A suitable amount of blocking agent, expressed as the equivalent weight of the hydroxyl groups of the blocking agent relative to the number of moles of isocyanate groups to be blocked, may range from at least 85 mole %, or at least 95 mole %, or preferably at least 100 mole %. A slight excess of blocking agent is preferred, for example up to 20 mole %, or at most 15 mole %, for example 5 to 15 mole %, based on the total number of moles of free isocyanate groups (i.e. available for blocking). or more preferably in an excess of at most 10 mol%. For example, the amount of blocker groups used for blocking can be 95 mole % to 110 mole % based on the number of moles of free isocyanate groups on the prepolymer.

A suitable amount of blocking agent is at least 1% by weight, or at least 3% by weight, or at least 5% by weight, or at least 7% by weight, or at least 9% by weight, based on the total weight of the reactants used to prepare the blocked isocyanate prepolymer. , or may range from 10% by weight or more. The amount of blocking agent is 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 reactants used to prepare the blocked isocyanate prepolymer. It can be included. Accordingly, the total amount of blocking agent is 1 to 60% by weight, or preferably 3 to 40% by weight, or preferably 5% to 40% by weight, based on the total weight of reactants used to prepare the blocked isocyanate prepolymer. may include.

In another aspect, the present invention provides a method of making a blocked isocyanate prepolymer composition comprising reacting one or more polyols with an excess polyisocyanate to form an isocyanate functional prepolymer, followed by the isocyanate functional prepolymer. blocking with a long-chain hydrocarbyl group-containing phenol blocking agent to form a blocked isocyanate prepolymer, and then reacting the blocked isocyanate prepolymer with the monohydric alcohol under conditions that cause reaction, for example at a temperature of 60 to 100° C. and adding a monohydric alcohol to the composition. More specifically, the method includes:

One or more polyols, preferably one or more diols or triols, for example polyether polyols with two or three hydroxyl functional groups, or mixtures thereof, with a molar excess of one or more polyisocyanates, preferably one or more aromatic An isocyanate-functional prepolymer is prepared by reaction with a diisocyanate, 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. manufacturing step;

The isocyanate functional prepolymer is preferably an alkyl phenol having C ₈ to C ₂₄ hydrocarbyl phenol groups, for example mono-, di- and/or tri-unsaturated hydrocarbyl groups, preferably mono-, di-, and/or or blocking with a phenol having tri-unsaturated pentadecylene groups, or more preferably with a mixture of mono-, di- and tri-unsaturated pentadecylene groups, for example with cardanol to form a blocked isocyanate prepolymer. steps; and

The blocked isocyanate prepolymer is added to a monohydric alcohol having a boiling point of at least 110° C., or preferably at least 150° C. and having a hydroxyl number of 60 to 500, preferably having at least one ether group, for example an alkoxypolymer. (alkylene glycol) or more preferably methoxy poly(ethylene glycol) (MPEG).

Formation of the isocyanate prepolymer, blocking it to form the blocked isocyanate prepolymer, and adding the monohydric alcohol to the blocked isocyanate prepolymer are each carried out at 60 to 100° C., or preferably 70 to 97° C. and combining the indicated materials to form a reaction mixture for a reaction period of, for example, 2 to 24 hours, such as less than 12 hours to 18 hours. The formation of the isocyanate prepolymer, its blocking and the addition of the monohydric alcohol each occur at 60 to 100° C., or preferably 70 to 97° C., with a reaction period of for example 1 to 8 hours, for example less than 1.5 hours to 4.5 hours. It may include reactions during the period. The addition of the monohydric alcohol may be carried out at 60 to 100° C., or preferably 70 to 97° C., for a reaction period of 1 to 6 hours, for example less than 1.5 hours to 4 hours. In each of the formation and blocking of the prepolymer, catalysts such as tertiary amines, metal containing catalysts such as tin catalysts, carboxylates such as mixed metal carboxylate catalysts such as zinc and zirconium carboxylates Acid salts may be added in customary amounts.

The blocked isocyanate prepolymers of the present invention can be used to prepare thermally conductive two-component compositions. Additionally, the prepolymers of the present invention may be utilized in other applications utilizing blocked isocyanate prepolymers, such as coatings, elastomers, adhesives, and epoxy composites.

Specific examples of compositions comprising blocked isocyanate prepolymers 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). Although fillers increase the viscosity of the paste composition, the viscosity of the paste must be low enough to allow mixing with the amine, which is the curing component in a curable two-component composition in which the isocyanate component is one component. The two components cure at 10 to 50° C. when combined. Suitable amines have a molecular weight determined by the hydroxyl number of the polyether used to prepare the polyether amine ranging from 300 Da to 5000 Da and a molecular weight of the polyether used to prepare the polyether amine ranging from 2.5 to 3.5. Primary polyether amines with hydroxyl functionality may be included. Particularly preferred are JEFFAMINE™ T-3000 and JEFFAMINE™ T-5000; the primary aliphatic JEFFAMINE™ series of polyether amines including JEFFAMINE™ T-403 (Huntsman Chemicals, Salt Lake City, Utah); Those available from BASF include Baxxodur™ EC 3003, Baxxodur™ EC 311, Baxxodur™ EC 310. Combinations of triamines, diamines and monoamines can be used to adjust the cure profile and mechanical properties, such as hardness, of the final product.

The cured product of the two-component composition has a relatively low cure hardness, as 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. These two-component compositions can be used as thermal interface materials in applications where heat must be removed from a heat source, such as an electric vehicle battery.

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

Hardening is indicated by an increase in viscosity after mixing the two components, and a cured solid with measurable hardness is finally formed. The cured composition may have a variety of cure hardnesses. The cured hardness, as measured according to ASTM D2240 using a Shore OO durometer, is preferably 40 to 95 Shore OO, or 50 to 90 Shore OO, or 60 to 85 Shore OO.

The composition may cure in less than 14 days, or less than 10 days, or preferably less than 7 days, but more than 30 minutes. The cured composition has a power rating of > 0.5 Watts/Meter Kelvin (W/m·K), or > 1 W/m·K, or most preferably > 1.5 W/m·K, or < 50 W/m·K. It can have a thermal conductivity of . 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/c.

The high thermal conductivity and low hardness described above make the curable composition particularly suitable for use as a gap filler for electric vehicle applications such as energy storage device assemblies. The curable composition can be used to transfer heat from a heat source to a heat sink. Additionally, pre-cured thermal interface gap pads can also be made from this composition. After curing the thermal gap pad to the desired thickness, it is cut into the desired shape and compressed into place.

The blocked isocyanate prepolymers of the present invention lower the hardness of the cured article, which is advantageous for gap fillers because lower hardness products can provide better thermal contact between the heat source and the heat sink.

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 include one or more additives. The blocked isocyanate prepolymer composition or 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.

The amine component includes one or more catalysts, which may or may not be non-acidic. Suitable catalysts may be carboxylates, tertiary amines, amidines, guanidines, diazabicyclo compounds, or combinations thereof. Non-acidic catalysts contain reactive groups such as active hydrogen.

The plasticizer may be admixed to either the blocked isocyanate component or the amine component in an amount of 0 to 20% by weight, or 2 to 12% or 4 to 10% by weight, based on the total weight of the two-component composition. Suitable plasticizers may be any of the common plasticizers useful in polyurethanes and well 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, trimethyl fentanyl diisobutyrate (TXIB); Alternatively, terephthalate may also be used. Other useful plasticizers may include partially hydrogenated terpenes, chloroparaffins, alkyl naphthalenes, etc., commercially available as glycol ether esters, "HB-40" (Eastman, Kingsport, Tenn.).

One, or preferably both, of the blocked isocyanate component and the amine component may include at least one filler. The amount of filler may range from 40 to 98 weight percent, or from 60 to 95 weight percent, or from 75 to 93 weight percent, or from 80 to 92 weight percent, all of which are weight percent, based on the weight of the two-component composition. Various filler sizes or fillers can be blended to achieve the desired filler loading and viscosity of the formulation. Preferably, the filler is aluminum trihydrate (ATH). Accordingly, according to the present invention, a thermally conductive two-component composition may comprise the blocked isocyanate prepolymer composition disclosed herein in various forms and preferred forms thereof,

As a separate component, it further comprises an amine composition, wherein at least one of the blocked isocyanate prepolymer composition or the amine composition has a weight of 60 to 98%, as measured based on the total weight of the blocked isocyanate prepolymer composition or amine composition, respectively. % by weight of thermally conductive filler.

Example

The following examples illustrate the invention. Unless otherwise specified, all temperatures are ambient (21 to 25° C.), all pressures are 1 atmosphere and relative humidity (RH) is 35 to 50%. Notwithstanding the fact that the numerical ranges and parameters disclosing the broad scope of the invention are approximations, the numerical values disclosed in the embodiments are reported as accurately as possible. However, all numerical values inherently contain certain errors, which are due to the standard deviation found in each measurement.

Materials used in the examples and not otherwise defined below are presented in Table 1 below. Abbreviations used in the examples include: Da: Dalton; EO: ethylene oxide; OHn: hydroxyl number; NCO: isocyanate; PO: propylene oxide; TXIB: (2,2,4-trimethyl-1,3-pentanediol diisobutyrate).

[Table 1]

Test Methods: In the examples below, the following test methods were used: Where applicable, the standard deviation of all data was within acceptable limits. All applicable test results are shown in Tables 2, 3, and 4 below.

Viscosity: The indicated material is placed between a Peltier plate (80 mm diameter with hardened chrome surface, TA instruments) and a 2-degree cone of 40 mm with a truncated gap of 54 microns rotating at a constant angular velocity while the Peltier plate remains stationary. at 25°C and 10 s ^-1 as measured using a deployed AR2000 rotary flow meter (TA Instruments) and running temperature sweeps from 25 to 50°C at a ramp rate of 3°C/min and a shear rate of 10 s ^{-1 .} of conical and flat viscosity. Once the gap was reached, the analyte sample was trimmed to remove any excess material.

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 marked sample was transferred to the ATR and infrared spectra were collected from 4000 to 650 cm ^-1 using a resolution of 4 cm ^-1 and 16 scans.

The isocyanate content (NCO content) of a particular composition was determined according to ASTM D5155-19, Test Method, using a Mettler DL55 (Mettler Toledo, Columbus, OH) automatic titrator equipped with two titration stands, a rinse pump, a volumetric pump, and an automatic sampler carousel. Measured according to C (2019). The sample was added to the trichlorobenzene solution delivered using a rinse pump, and 2 N dibutylamine (in toluene) was dispensed into the automated titrator using a 20 mL burette. The resulting mixture was stirred for 20 minutes. The reaction mixture was then diluted with methanol, distributed through a volumetric pump, and back-titrated with 1 N hydrochloric acid (aqueous solution) using a 20 mL burette.

Storage stability: Storage stability was observed by aging the indicated compositions in an oven at 60°C for 2 weeks (14 days).

Thermal conductivity was measured according to ISO 22007-2 using a Hot Disk Thermal Constants analyzer (TPS 2500S, Thermtest Instruments, Fredericton, New Brunswick, Canada). All measurements were performed with a Kapton built-in thermal probe using two-sided measurement with two 6 mm cups at 150 mW heating power and 5 second measurement time.

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

Compression force was measured using a TA instruments TA-XT plus texture analyzer equipped with a 50 kg load cell. After dispensing the paste onto a flat, rigid aluminum substrate, a 40 mm diameter acrylic probe was lowered to sandwich the test material on the flat substrate to achieve a standard 5.0 mm gap thickness. Any excess overflow material was trimmed with a flat-edged spatula. After trimming, the test was started and the probe was moved at a speed of 1.0 mm/sec to a final thickness of 0.3 mm while the force was recorded. The specific force values recorded at intervals of 0.5 mm are reported as “squeezing force”. The lower the compression force, the better the results.

Specific gravity was determined by weighing the samples in air and water according to ASTM D 792-00.

Synthesis Examples: The blocked isocyanate prepolymer materials tested in the examples below and compositions comprising them were prepared as follows:

In Comparative Examples (CE) CE1 to CE3, all are prepolymers made from toluene diisocyanate (TDI) and polyether diol with various NCO contents, catalysts or process conditions. The NCO% of each prepolymer is reported in the table.

CE1: 35.05 g of TDI was weighed in a speed mixer cup, 115.01 g of polyether diol and 0.0155 g of tin catalyst were charged, mixed at 2350 RPM for 1 minute, and placed in an oven at 70°C for reaction for about 2 hours. Decomposition occurred to form NCO prepolymer. Weigh 110 g of NCO prepolymer in a speed mixer cup, charge 0.03 g of T-9 catalyst and 53.92 g of cardanol, mix at 2350 RPM for 2 to 3 minutes, then transfer to a dry glass bottle and mix at 80 to 85°C. I put it in the oven. The temperature was maintained at approximately 85°C for 4.5 hours in the oven.

CE2: 28.35 g of TDI were weighed in a dry 500 ml dry reactor equipped with an overhead stirrer, N ₂ inlet and N ₂ outlet, thermocouple and heating mantle. 172 g of polyether diol (water content 72 ppm) and 0.0275 g (about 129 ppm) of tin catalyst were charged. The mixture was stirred at 300-500 RPM and slowly heated to 70-75° C., at which temperature the reaction decomposed for about 2.0 hours to form the isocyanate prepolymer and the NCO content was measured. Tin catalyst (0.115 g, 500 ppm) was added to 171 g of isocyanate prepolymer in the reactor, and the mixture was heated to 95°C while stirring. Using an addition funnel, 41.6 g of cardanol was charged dropwise over about 15 minutes. The temperature was maintained at approximately 95° C. for 2 hours, then additional tin catalyst (0.115 g, 500 ppm) was added and held for a further 2 hours.

Example 2: 207.61 g of NCO prepolymer of CE2 was charged with 2.21 g of MPEG (about 1% by weight) and the temperature was maintained at 95°C for 2 hours.

CE3: 28.06 g of weighed TDI were charged with 172.2 g of polyether diol (water = 103 ppm) in a dry 500 ml dry reactor equipped with an overhead stirrer, N ₂ in and N ₂ out, thermocouple and heating mantle and reacted in TXIB. 0.0439 g of 50% by weight mixed carboxylate 2 with zinc and zirconium was charged. The resulting mixture was stirred at 300-500 RPM and slowly heated to 75-80° C., at which temperature 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.

175 g of prepolymer in the reactor was slowly heated to 95° C. with stirring and 0.2330 g of mixed carboxylate 2 catalyst with zinc and zirconium was charged. Then, 42.5 g of cardanol was charged using an addition funnel, and the dropwise addition was completed within about 25 minutes. The temperature was maintained at 95°C until the reaction was complete, which lasted for 2 hours. Afterwards, blocking was continued for an additional 2 hours using an additional 0.2288 g of catalyst, and the reaction proceeded for an additional 2 hours. FT-IR was performed both before and after blocking. The area coefficient of the isocyanate peak in FTIR can be found in Table 3 below.

Example 3: 1% by weight of MPEG was charged to 212.5 g of prepolymer of CE3, and the reaction was carried out at 95°C for 1.5 hours.

Example 4: 47 g of TDI were weighed in a dry 500 ml dry reactor equipped with an overhead stirrer, N ₂ inlet and N ₂ outlet, thermocouple and heating mantle. To this was charged 153 g of polyether diol and then 0.0439 g of 50% by weight mixed carboxylate 2 with zinc and zirconium in TXIB was charged to the reactor. The mixture was stirred at 300-500 RPM and heated slowly to 75-80°C. The heated mixture was allowed to react for about 2.0 hours, then the reaction was stopped and cooled to 25° C. to form the NCO prepolymer. NCO content was measured.

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

11.9 g (about 4.2% by weight) of MPEG was added to 284 g of prepolymer and decomposed at 95°C for 1 hour.

Example 5: 35.5 g of TDI were weighed in a dry 250 ml dry reactor equipped with an overhead stirrer, N ₂ inlet and N ₂ outlet, thermocouple and heating mantle. 115.5 g of polyether diol (water = 204 ppm) and about 0.0202 g (about 134 ppm) of tin catalyst were charged to the reactor and the mixture was stirred at 300-500 RPM while slowly heating at 70-75°C. The reaction was allowed to digest for approximately 2.25 hours. The reaction was stopped and cooled to 25° C. under N ₂ . The NCO content of the isocyanate prepolymer was measured.

500 ppm (0.0976 g) of tin catalyst was added to 113 g of isocyanate prepolymer in the reactor, and the mixture was heated to 95°C while stirring. 67.2 g of cardanol was added using an addition funnel, and the dropwise addition was completed within about 10 minutes. The temperature was maintained at about 95°C for 7 hours, then 1.78 g of MPEG (about 1% by weight) 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.

Example 6: 62.55 g of TDI were weighed in a dry 500 ml dry reactor equipped with an overhead stirrer, N ₂ inlet and N ₂ outlet, thermocouple and heating mantle. 137.75 g of polyether diol (water = 68 ppm) and 0.02 g of tin catalyst were charged to the reactor. The mixture was stirred at 300-500 RPM, heated slowly to 70-75° C., and decomposed for about 2.25 hours to form the isocyanate prepolymer. NCO content was measured.

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

Example 7: 70.4 g of TDI were weighed in a dry 500 ml dry reactor equipped with an overhead stirrer, N ₂ inlet and N ₂ outlet, thermocouple and heating mantle. 80.25 g of polyether diol (water = 68 ppm) and 0.018 g (about 120 ppm) of tin catalyst were charged to the reactor. The mixture was stirred at 300-500 RPM and heated slowly to 70-75°C. The reaction decomposed for about 2.25 hours to form the isocyanate prepolymer. Then the NCO content was measured.

1000 ppm (0.404 g) of tin catalyst was charged to 130.2 g of isocyanate prepolymer in the reactor, and the resulting mixture was heated to 95°C while 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 approximately 95° C. for 6 hours to form a blocked isocyanate prepolymer. 3.45 g (about 1% by weight) of MPEG was charged to the blocked isocyanate prepolymer and the temperature was maintained for 1 hour and 30 minutes.

[Table 2]

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

Table 3 below shows the area coefficients for the NCO FT-IR peak (2270 cm ^-1 ) after addition of isocyanate prepolymer, optional cardanol blocked prepolymer and MPEG. As can be seen in Table 3 below, after adding MPEG, no peak was detected or a very small isocyanate signal was detected through FT-IR. After MPEG addition, all of the prepolymers of the present invention showed a very small or undetectable NCO peak at 2270 cm ^-1 in FTIR. Isocyanate content was estimated from an internally generated calibration curve using TDI as a benchmark. Therefore, through the FT-IR spectrum, it was confirmed that the NCO peak at a wavelength of 2269 to 2272 cm ^-1 was reduced by cardanol blocking, and further decreased when the blocked prepolymer was treated with MPEG.

[Table 3]

Two-component curable composition with high thermal conductivity:

Examples 8A and 8B below provide curable compositions with high thermal conductivity formed using the blocked isocyanate prepolymers of the present invention. The examples demonstrate the utility of the blocked isocyanate prepolymer of Example 4 in forming curable two-component thermally conductive compositions for use as gap fillers for EV batteries. The components shown in Table 4 below for Examples 8A (blocked isocyanate composition) and 8B (amine composition) were mixed separately using a high speed mixer to obtain two separate thermally conductive pastes. As shown in the table below, both components individually have high thermal conductivity and low compressive force. To measure the mixture properties, the two components were mixed at 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 portion with a Shore OO hardness of 70 to 75, high thermal conductivity (about 3 W/m·K) and low specific gravity (about 2.03 gm/cc). . These properties make this composition useful as a thermally conductive gap filler.

[Table 4]

CE9: 64 g (734.8 mEq.) of toluene diisocyanate (T-80 Type I) was weighed in a 500 ml oven dry reactor and equipped with an overhead stirrer, N2 inlet and N2 outlet tubes, thermocouple and heating mantle. 336 g of polyether diol (341.54 mEq.) and 100 ppm (0.04 g) of tin catalyst were charged. The mixture was stirred at 300 to 500 RPM and heated slowly to obtain 75 to 80°C. The mixture decomposed for approximately 2.0 hours and the desired NCO was achieved. Measured NCO % = 4.16.

150 g of 4.16% TDI prepolymer was charged into a 500 ml dry reactor, installed with an overhead stirrer, N2 inlet and N2 outlet tubes, thermocouple and heating mantle, and heated to 75 to 80° C. while stirring. Approximately 1000 ppm of Dabco 33LV catalyst and 47.0 g of cardanol were charged. The temperature reached 80°C in about 10 minutes. After continuing the reaction for 2 hours, the isocyanate concentration was analyzed using FT-IR. An in-house calibration curve method was used to find a concentration of 0.41% NCO. A second aliquot of approximately 1000 ppm of Dabco 33LV catalyst was added and blocking continued for an additional 3 hours. No significant reduction of the isocyanate peak was observed. The calculated NCO was confirmed to be 0.38%, and approximately 10 g of product was discharged for analysis.

Example 9: 190 g of blocked prepolymer of CE-9 was charged into a dry 500 ml reactor and equipped with an overhead stirrer, N2 inlet and outlet tubes, thermocouple and heating mantle. 1.0 wt % MPEG (1.9 g) was charged with stirring and digested at 75-80°C for 1 hour. Isocyanate concentration was confirmed to be 0.26% through FT-IR. Blocking is considered complete. 0.5 g of benzoyl chloride was charged. The product was discharged into a container.

CE10: 94 g of toluene diisocyanate (T-80 Type I) was charged into a 500 ml oven dry reactor and equipped with an overhead stirrer, N2 inlet and N2 outlet tubes, thermocouple and heating mantle. 306 g of polyether diol and 0.04 g of tin catalyst were charged. The mixture was stirred at 300 to 500 RPM and heated slowly to obtain 75 to 80°C. The mixture decomposed for approximately 2.0 hours and the desired NCO was achieved. Measured NCO % = 8.3

150 g of 8.33% TDI prepolymer was charged into a 500 ml dry reactor, installed with an overhead stirrer, N2 inlet and N2 outlet tubes, thermocouple and heating mantle, and heated to 75 to 80° C. while stirring. Approximately 1000 ppm of Dabco 33LV catalyst and 94.0 g of cardanol were charged. The temperature reached 80°C in about 10 minutes. The reaction was continued for 2 hours, a second aliquot of approximately 1000 ppm of Dabco 33LV catalyst was added and blocking continued for an additional 3 hours.

Example 10: 234 g of blocked prepolymer of CE-10 was charged into a dry 500 ml reactor and equipped with an overhead stirrer, N2 inlet and outlet tubes, thermocouple and heating mantle. 1.0 wt % MPEG (2.30 g) was charged with stirring and digested at 75-80°C for 1 hour. 0.5 g of benzoyl chloride was charged. The product was discharged into a container.

CE11: 124 g of toluene diisocyanate (T-80 Type I) was charged to a 500 ml oven dry reactor and equipped with an overhead stirrer, N2 inlet and N2 outlet tubes, thermocouple and heating mantle. 276 g of polyether diol and 0.04 g of tin catalyst were charged. The mixture was stirred at 300 to 500 RPM and heated slowly to obtain 75 to 80°C. The mixture decomposed for approximately 2.0 hours and the desired NCO was achieved. Measured NCO % = 12.23.

150 g of 12.23% TDI prepolymer was charged into a 500 ml dry reactor, installed with an overhead stirrer, N2 inlet and N2 outlet tubes, thermocouple and heating mantle, and heated to 75 to 80° C. while stirring. About 1000 ppm of Dabco 33LV catalyst and 139 g of cardanol were charged. The temperature reached 80°C in about 10 minutes. The reaction was continued for 2 hours. A second aliquot of approximately 1000 ppm of Dabco 33LV catalyst was added and blocking continued for an additional 3 hours.

Example 11: 278 g of blocked prepolymer of CE11 was charged into a dry 500 ml reactor and equipped with an overhead stirrer, N2 inlet and outlet tubes, thermocouple and heating mantle. 1.0 wt % MPEG (2.80 g) was charged with stirring and digested at 75-80°C for 1 hour. 0.7 g of benzoyl chloride was charged. The product was discharged into a container.

[Table 5]

CE12 : 434.2 g of TDI (T-80 type (I)) was charged into a dry 3 L dry reactor and equipped with an overhead stirrer, N2 inlet and N2 outlet, thermocouple and heating mantle. 966.3 g of V2000LM polyol was charged and stirred for 10 minutes. Then, 0.28 g of 50 wt% KKAT XK604 catalyst in TXIB was charged to the reactor. The mixture was stirred at 300 to 500 RPM and heated slowly to obtain 75 to 80°C. The mixture decomposed for approximately 2.0 hours and the desired NCO was achieved.

1229 g of TDI prepolymer was charged into a 3 L dry reactor, equipped with an overhead stirrer, N2 inlet and N2 outlet, thermocouple and heating mantle, and heated to 95°C while stirring. 0.2874 g of 50% mixed carboxylate of zinc and zirconium in TXIB 2 was charged. 1169 g of cardanol (1.05 eq.) was charged dropwise using an addition funnel, complete in approximately 25 to 30 minutes. Upon completion the temperature reached 95°C. After continuing the reaction for 2 hours, the isocyanate concentration was analyzed using FT-IR. An in-house calibration curve was used to find an NCO concentration of 2.33%. An additional 500 ppm of mixed carboxylate 2 catalyst of zinc and zirconium was charged and further decomposed for 2 hours and then the isocyanate concentration was analyzed using FT-IR technique. 0.57% NCOs were found.

Example 12: 534 g of blocked prepolymer of CE 12 was charged to a dry 1 L reactor and equipped with an overhead stirrer, N2 inlet and outlet, thermocouple and heating mantle. 2.4 wt% MPEG (12.9 g) and 100 ppm (0.1068 g) of 50 wt% KKAT XK-604 catalyst were charged with stirring and digested at 95°C for 2 hours. Isocyanate concentration was confirmed to be 0.30% through FT-IR. The product was discharged into a container.

Two-component curable composition with high thermal conductivity:

Examples 13 and CE13: Examples 13 and CE13 below provide curable compositions with high thermal conductivity formed using the blocked isocyanate prepolymers of the present invention. For Example 13 and Comparative Example 13, the components shown in the table below were mixed separately using a high speed mixer to obtain individual thermally conductive pastes for A&B sides. The individual pastes have high thermal conductivity and low compression force.

The compressive strength of the individual A-side and B-side compositions of Example 13 shows minimal (<20%) change after aging for 1 week at 60°C, indicating that the thermally conductive compositions prepared from the inventive prepolymers have good storage stability. It shows that it has.

To measure hardness, the two components were mixed at a 1:1 weight ratio, mixed using a high speed mixer, and cured at room temperature for 14 days.

The following examples show that the use of the MPEG-terminated prepolymer in Example 13 resulted in lower hardness of the cured part compared to the prepolymer without MPEG in Comparative Example 13. Lower hardness is preferred for gap fillers because lower hardness products can provide better contact between the heat source and the heat sink, demonstrating the advantages of the prepolymers of the present invention.

[Table 6]

Claims (12)

As a fluid composition,
C ₈ to C ₂₄ hydrocarbyl group-containing phenol blocked isocyanate prepolymer, wherein the blocked isocyanate prepolymer has a boiling point of 110° C. or higher at 1 atm (101.325 KPa) and has a hydroxyl number of 60 to 500. A fluid composition further comprising an alcohol in copolymerized form. 2. The method of claim 1, wherein the C ₈ to C ₂₄ hydrocarbyl group-containing phenol in the blocked isocyanate prepolymer comprises an alkyl phenol having mono-, di- or tri-unsaturated hydrocarbyl groups, or a combination of two or more thereof. , fluid composition. 3. The fluid composition of claim 2, wherein the C ₈ to C ₂₄ hydrocarbyl group-containing phenol in the blocked isocyanate prepolymer is cardanol. 2. The method 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. a fluid composition. The fluid composition of claim 1, wherein the monohydric alcohol has a boiling point of at least 150° C. 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 methoxy poly(ethylene glycol). A fluid composition wherein the amount of 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 prepare the blocked isocyanate prepolymer. 3. The method of claim 1, wherein the composition uses a rotary flow meter disposed between an 80 mm diameter Peltier plate and a 40 mm 2-degree cone rotating at a constant angular rate while the Peltier plate remains stationary and is heated to a temperature of 3°C. has a cone and plate viscosity ranging from 8 to 50 Pa·s at 25°C and 10 s ^-1 , as measured by running a temperature sweep from 25 to 50° C. at a ramp rate of minutes and a shear rate of 10 s ^-1 ;
Additionally, the composition exhibits improved storage stability with less than a 20% change in cone and plate viscosity (25°C and 10 seconds ^-1 ) after 14 days storage at 60°C. A thermally conductive composition prepared from the fluid composition of claim 1. A thermally conductive composition, comprising:
C ₈ to C ₂₄ hydrocarbyl group-containing phenol blocked isocyanate prepolymer, wherein the blocked isocyanate prepolymer has a boiling point of 110° C. or higher at 1 atm (101.325 KPa) and has a hydroxyl number of 60 to 500. further comprising alcohol in copolymerized form;
The thermally conductive composition has a thermal conductivity of > 0.5 W/m·K. A process for preparing a blocked isocyanate prepolymer with improved storage stability as claimed in claim 1, comprising:
reacting one or more polyols with a molar excess of one or more polyisocyanates to prepare an isocyanate functional prepolymer;
blocking the isocyanate functional prepolymer with a C ₈ to C ₂₄ hydrocarbyl group-containing phenol; and
A method comprising adding to the blocked isocyanate prepolymer a monohydric alcohol having a boiling point of 110° C. or higher and having a hydroxyl number of 60 to 500 under conditions such that the blocked isocyanate prepolymer and the monohydric alcohol react with each other. .