Multilayer structure containing a low-viscosity polyurethane potent composition

Abstract

The multilayer composition may include at least one first layer containing a thermosetting resin, and a second layer containing a reaction product between at least one first layer and isocyanate components containing one or more isocyanate compounds, isocyanate-reactive components containing one or more polyether polyols, one or more aliphatic polyols, and at least one hollow particle present in at least one of the isocyanate components, isocyanate-reactive components, or a third component. The method may include preparing the multilayer composition, which includes depositing at least one layer of thermosetting resin onto a substrate and arranging the second layer on top of at least one layer of thermosetting resin.

Description

[Technical Field]

[0001] The embodiments relate to a low-viscosity polyurethane composition, a method for preparing the same, and applications for using the same. [Background technology]

[0002] Electric vehicles (EVs) operate with battery packs, where individual cells are arranged in close proximity in different patterns, along with cooling mechanism-related components and other parts. The geometric shape and form of the battery can be cylindrical, rectangular / prismatic, and / or pouched. Potent-like materials with different chemical properties, including silicone and polyurethane, can be used to connect these cells with the surrounding components. The main purposes of potent and / or encapsulating materials in batteries are to provide insulation between battery cells during use (minimizing the effects of thermal events, including cascading damage between adjacent cells), and, in some cases, to increase the strength of the battery assembly to withstand stress and deformation as a structural element of the vehicle. Polyurethane foams are also used as potent in some applications to reduce weight and improve efficiency and handling. However, in many cases, there is a trade-off with the durability and heat resistance of such materials. [Overview of the Initiative]

[0003] In one embodiment, the embodiments disclosed herein include a multilayer composition comprising: at least one first layer containing a thermosetting resin; an isocyanate component set on at least one first layer and containing one or more isocyanate compounds; an isocyanate-reactive component containing one or more polyether polyols, one or more aliphatic polyols; and a second layer containing a reaction product of one or more hollow particles present in at least one of the isocyanate component, the isocyanate-reactive component, or a third component.

[0004] In one embodiment, the embodiments disclosed herein include a method for preparing a multilayer composition, comprising depositing at least one layer of a thermosetting resin on a substrate, and distributing a second layer on at least one layer of the thermosetting resin, the second layer containing an isocyanate component containing one or more isocyanate compounds, an isocyanate-reactive component containing one or more polyether polyols, one or more aliphatic polyols, and a reaction product of one or more hollow particles present in at least one of the isocyanate component, the isocyanate-reactive component, or a third component. [Modes for carrying out the invention]

[0005] Embodiments relate to polyurethane (PU) compositions for potents and electronic materials having low viscosity to increase fluidity and permeability during application and reduce expansion or foaming. PU compositions can also produce materials with high strength, low density, and low thermal conductivity upon curing. In particular, developed PU applications can exhibit density reduction without requiring the incorporation of chemical or physical foaming agents. Methods disclosed herein also include preparing and applying PU compositions as potents, encapsulants, or thermal barriers, particularly in electronic and / or automotive applications.

[0006] In addition to their application as single materials, the PU compositions disclosed herein may be used as part of multilayer compositions having other compatible thermosetting resins. In particular, some thermosetting resins used as potents and in thermal management applications (e.g., battery assemblies) may foam or expand, resulting in variations in surface and layer thickness from the natural distribution of voids or phases throughout the material. Unreliable placement of foamable thermosetting resins and lack of thickness control can lead to inadequate coverage and poor performance. For example, improper placement of a potent on a battery cell can create a risk of thermal events and fire, even if the potent is FR rated. Irregular layer coverage of functional components can also cause problems. If the potent layer is too thick, vents and other features may not be able to release the gases they build up, potentially increasing the risk of explosion.

[0007] The PU compositions disclosed herein may be self-leveling and can be applied with consistent layer coverage and thickness without concern for excessive or under-expansion. In some cases, the self-leveling PU compositions disclosed herein may be used as a capping layer in a multilayer configuration having foamed PU to produce a flat finish surface for thermal management applications, such as capping thermosetting potents dispersed between assemblies of battery cells. The self-leveling compositions may cap the battery surface and form a uniform layer of 0.1 to 7 mm thickness on the top of the battery above the battery height. In one application, a first layer containing a low-density foamed potent (e.g., 0.65 g / mL or less, or 0.5 g / mL or less) covering or enclosing about 1% to 70% of the battery cell height, and a second layer (capping layer) containing the PU composition disclosed herein, are used to cover the remaining height of the battery cell and provide a uniform, flat surface. This configuration allows for the incorporation of low-density / low-weight materials for weight reduction, improved fuel economy, and increased vehicle range (measured in miles or kilometers), while increasing thermal management characteristics for functionality and safety.

[0008] The PU compositions disclosed herein generally comprise a two-component curable composition, i.e., a product obtained by combining an isocyanate component ("side A") and an isocyanate-reactive component ("side B"). During application, the isocyanate and isocyanate-reactive components are mixed to initiate a curing reaction and form a polyurethane article or material. The PU composition may also comprise one or more hollow particles added to the isocyanate and / or isocyanate-reactive component (or as a third component added during mixing) to reduce the overall composition density and modify various mechanical properties.

[0009] The polyurethane compositions disclosed herein may contain an isocyanate component comprising one or more isocyanate compounds, such as polymer isocyanates, aromatic isocyanates, or carbodiimide-modified isocyanates. The isocyanate compound may be a monomer, oligomer, prepolymer, etc. The isocyanate component may comprise, for example, one or more isocyanate and / or polyisocyanate compounds. The isocyanate component may comprise an isocyanate compound having a nominal functional value greater than 1.5, greater than 2.0, or in the range of 1.5 to 4. The polyurethane composition may contain the isocyanate component in weight percent (W%) in the range of 15% to 80% by weight, 20% to 80% by weight, or 25% to 80% by weight.

[0010] The isocyanate component may include isocyanate compounds having a number-average molecular weight of 150 g / mol to 750 g / mol. In some cases, the isocyanate compounds may have a number-average molecular weight ranging from a lower value of 150 g / mol, 200 g / mol, 250 g / mol, or 300 g / mol to an upper value of 350 g / mol, 400 g / mol, 450 g / mol, 500 g / mol, or 750 g / mol. The number-average molecular weight values ​​reported herein are determined by end-group analysis, gel permeation chromatography, and other methods known in the art. The isocyanate compounds may be monomers and / or polymers known in the art.

[0011] In some cases, the isocyanate component may include an isocyanate compound having an isocyanate content of 10% or more by weight, 20% or more by weight, 30% or more by weight, or in the range of 10% to 50%.

[0012] The isocyanate component may include one or more of the following: aliphatic polyisocyanates, alicyclic polyisocyanates, aromatic aliphatic polyisocyanates, aromatic polyisocyanates, etc. Examples of isocyanates include, but are not limited to, polymethylene polyphenyl isocyanate, toluene 2,4- / 2,6-diisocyanate (TDI), methylenediphenyl diisocyanate (MDI, including its isomers), polymers and prepolymers MDI, triisocyanatononane (TIN), naphthyl diisocyanate (NDI), 4,4'-diisocyanatodicyclohexylmethane, 3-isocyanatomethyl-3,3,5-trimethylcyclohexyl isocyanate (isophorone diisocyanate, IPDI), tetramethylene diisocyanate, and hexamethylene diisocyanate. Examples include diisocyanate (HDI), 2-methyl-pentamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate (THDI), dodecamethylene diisocyanate, 1,4-diisocyanatocyclohexane, 4,4'-diisocyanato-3,3'-dimethyl-dicyclohexylmethane, 4,4'-diisocyanato-2,2-dicyclohexylpropane, 3-isocyanatomethyl-1-methyl-1-isocyanatocyclohexane (MCI), 1,3-diisooctylcyanato-4-methylcyclohexane, 1,3-diisocyanato-2-methylcyclohexane, and combinations thereof. In addition to the isocyanates described above, modified or partially modified polyisocyanates, particularly those containing uretdione, isocyanurate, carbodiimide, uretonimine, allophanate, or biuret structures, and combinations thereof, may also be used.For example, the isocyanate compound may include carbodiimide-modified MDI.

[0013] The isocyanate compounds may include isocyanate prepolymers resulting from the reaction of an isocyanate-reactive compound with a molar-excess isocyanate compound or polymer isocyanate compound under conditions that do not cause gelation or solidification, and the isocyanate prepolymers may have a higher average isocyanate equivalent of more than 400 g / eq. The formation of isocyanate prepolymers is known in the art and may involve reacting (1) at least one isocyanate compound with (2) at least one polyol compound. The isocyanate prepolymers may also be described by an isocyanate index, which is defined as the ratio of isocyanate groups to isocyanate-reactive groups (e.g., OH groups) multiplied by 100. The isocyanate prepolymers disclosed herein may have an isocyanate index in the range of 30-400, 40-300, or 40-200, where the isocyanate index is defined as the amount of isocyanate equivalent divided by the total amount of isocyanate-reactive hydrogen-containing material and multiplied by 100.

[0014] Examples of commercially available isocyanates include, but are not limited to, polyisocyanates under the trade names VORANATE®, PAPI®, VORATRON®, VORAFORCE®, and ISONATE®, all of which are available from The Dow Chemical Company.

[0015] The isocyanate-reactive component may include a polyol blend containing one or more polyether polyols, polyester polyols, aliphatic polyols, polyol crosslinking agents, and hollow particles, as well as other additives such as catalysts and surfactants. The polyurethane composition may contain the isocyanate-reactive component in weight percentages (wt%) ranging from 20% to 85% by weight, 20% to 80% by weight, or 25% to 80% by weight.

[0016] The isocyanate-reactive component may include one or more polyether polyols prepared by polyadding an alkylene oxide, such as propylene oxide and / or ethylene oxide, to a polyhydroxy-functional starter compound in the presence of a catalyst known in the art. The polyether polyol can be prepared from the starter compound and one or more alkylene oxides, such as ethylene oxide, propylene oxide, and / or butylene oxide. Examples of starter compounds include, but are not limited to, molecules having 1 to 8 hydroxyl groups per molecule, such as ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol, 1,4-butanediol, 1,6-hexanediol, triethanolamine, diethanolamine, diisopropanolamine, bisphenol A, glycerol, diglycerol, triglycerol, trimethylolpropane, di(trimethylolpropane)pentaerythritol, dipentaerythritol, tripentaerythritol, sugars and sugar alcohols such as sucrose and sorbitol. For the purposes of the present invention only, it is understood that a polyether polyol may be a blend of any of these polyether polyols with one or more starter compounds, and that a polyether polyol may be one or more starter compounds themselves. Polyether polyols may include polyols formed by reacting polyethers with copolymers of alkylene oxides containing block copolymers, as well as polyethers "capped" with hydroxyethyl and / or hydroxypropyl oligomers or polymers.

[0017] Polyether polyols may have a hydroxyl functional value in the range of 1 to 8, or 1.5 to 7. Polyether polyols may have a hydroxyl equivalent in the range of 30 Da to 4000 Da, or 30 Da to 3000 Da, where the hydroxyl equivalent is defined as the weight-average molecular weight of the polyol divided by the average number of hydroxyl groups in the molecule or the average hydroxyl functional value.

[0018] The isocyanate-reactive component may include at least one polyether polyol present in weight percent (W%) of 40% to 95%, 45% to 95%, or 50% to 90%.

[0019] The isocyanate-reactive component may include one or more polyester polyols produced by the reaction of one or more carboxylates with polyols having an OH functional value of 2 to 4. Suitable carboxylic acids include aromatic diacides or anhydrides, such as phthalic acid, phthalic anhydride, isophthalic acid, terephthalic acid, phthalic acid, isophthalic acid, or methyl esters of terephthalic acid, dimethyl terephthalate, trimellitic anhydride, pyromellitic dianhydride, or mixtures thereof; and C4-C12 aliphatic diacides. Suitable polyols for polyester formation include one or more alkylene glycols or polyalkylene glycols having a hydroxyl functional value of 2 to 4, such as ethylene glycol, 1,2- or 1,3-propylene glycol, 1,4-butanediol, 1,6-hexanediol, diethylene glycol, and glycerin. Examples of polyester polyols include polyesters of phthalic anhydride and diethylene glycol, and polyesters of C4-C12 diacids such as succinic acid or adipic acid and diethylene glycol.

[0020] The polyester polyol may have an average hydroxyl value (OH value) in the range of 100 mg KOH / g to 500 mg KOH / g, 150 mg KOH / g to 450 mg KOH / g, or 150 mg KOH / g to 450 mg KOH / g, as determined according to ASTM D4274-21. The isocyanate-reactive component may contain one or more polyester polyols in weight percentage (W%) in the range of 10% to 40% to 15% to 35% to 15% to 30% to 15

[0021] The isocyanate-reactive component may include one or more aliphatic polyols having at least two reactive hydroxyl groups. Examples of the aliphatic polyol include natural and synthetic polyester polyol derivatives, and products formed from the reaction of a polyol with one or more hydroxy fatty acids having 10 to 20 carbon atoms, including hydroxycapric acid, hydroxylauric acid, hydroxymyristic acid, hydroxypalmitic acid, hydroxymalargic acid, hydroxystearic acid, hydroxyeicosanoic acid, ricinoleic acid, etc. For example, as the aliphatic polyol, there may be mentioned triglycerides containing a partial fraction of hydroxy fatty acids such as castor oil or its derivatives, and / or polyols prepared from epoxidized or hydroformylated natural oils such as soybean oil, cashew nut shell liquid (i.e., CNSL (cashew nut shell liquid)). The aliphatic polyol may have a hydroxyl equivalent in the range of 30 Da to 2500 Da, or 30 Da to 2000 Da.

[0022] The isocyanate-reactive component may include one or more aliphatic polyols in a weight percentage (wt%) of 2 wt% to 25 wt%, 5 wt% to 25 wt%, or 5 wt% to 20 wt%.

[0023] The isocyanate-reactive component may include one or more polyol crosslinking agents having at least three hydroxyl functionalities and a weight average molecular weight of 800 g / mol or less. Suitable polyol crosslinking agents may include glycerol, diglycerol, triglycerol, trimethylolpropane, di(trimethylolpropane), pentaerythritol, dipentaerythritol, tripentaerythritol, sorbitol, derivatives such as alkoxylates, or combinations thereof.

[0024] The isocyanate-reactive component may include one or more polyol crosslinking agents in a weight percentage (wt%) of 1 wt% to 15 wt%, 1 wt% to 10 wt%, or 1 wt% to 5 wt%.

[0025] <The isocyanate-reactive component may include one or more silicone polyols having at least two reactive hydroxyl groups (e.g., diols, triols, polyols). The silicone polyol may include a siloxane bond (Si-O-Si) within its backbone and may optionally further include a divalent alkyl group separating the siloxane units. The silicone polyol may have the general formula HO-R 1 -Si(R 2 )2-[O-Si(R 2 )2] n -R 1 -OH, where each R 1 is independently a linking group having from 0 to 18 carbon atoms, and each R 2 is independently a group having from 2 to 18 carbon atoms such as alkyl or hydroxyalkyl, and where n is from 10 to 20.

[0026] The isocyanate-reactive component may include one or more silicone polyols in the range of 10 wt% to 40 wt%, 15 wt% to 35 wt%, or 15 wt% to 30 wt% by weight percent (wt%).

[0027] The isocyanate-reactive component may include one or more catalysts for enhancing polyurethane polymerization to produce a PU composition. The catalysts may be used individually or as a catalyst package containing a plurality of catalysts such as a gelling catalyst, a blowing catalyst, and a trimerization catalyst. The gelling catalyst and the blowing catalyst may be distinguished by a tendency to favor either the urethane (gel) reaction in the case of the gelling catalyst or the urea (blow) reaction in the case of the blowing catalyst. The trimerization catalyst can be utilized to promote the isocyanurate formation reaction in the composition. The catalyst package can also be added as a separate stream into the reaction mixture of the isocyanate and the isocyanate-reactive composition.

[0028] Examples of gelling catalysts include organometallic compounds, cyclic tertiary amines and / or long-chain amines (e.g., those containing several nitrogen atoms), and combinations thereof. Examples of organometallic compounds include tin(II) salts of organic carboxylic acids, such as tin(II) diacetate, tin(II) dioctanoate, tin(II) diethylhexanoate, and tin(II) dilaurate, and organotin compounds such as dialkyltin(IV) salts of organic carboxylic acids, such as dibutyltin diacetate, dibutyltin dilaurate, dibutyltin maleate, and dioctyltin diacetate. Bismuth salts of organic carboxylic acids can also be used as gelling catalysts, such as bismuth octanoate. Cyclic tertiary amines and / or long-chain amines include dimethylbenzylamine, triethylenediamine, and combinations thereof. Examples of commercially available gelling catalysts include, among other commercially available gelling catalysts, POLYCAT® 8, DABCO® 33-LV, and DABCO® T-12 from Evonik.

[0029] The foaming catalyst may include, in particular, bis-(2-dimethylaminoethyl) ether, pentamethyldiethylenetriamine, triethylamine, tributylamine, N,N-dimethylaminopropylamine, dimethylethanolamine, N,N,N',N'-tetramethylethylenediamine, and combinations thereof. An example of a commercially available foaming catalyst is POLYCAT® 5 from Evonik, among other commercially available foaming catalysts.

[0030] Trimerization catalysts may include any such catalysts known in the art. Examples of trimerization catalysts include N,N',N''-tris(3-dimethylaminopropyl)hexahydro-S-triazine; N,N-dimethylcyclohexylamine; 1,3,5-tris(N,N-dimethylaminopropyl)-s-hexahydrotriazine; [2,4,6-tris(dimethylaminomethyl)phenol]; potassium acetate, potassium octanoate; tetraalkylammonium hydroxides such as tetramethylammonium hydroxide; alkali metal hydroxides such as sodium hydroxide; alkali metal alkoxides such as sodium methoxide and potassium isopropoxide; and alkali metal salts of long-chain fatty acids having 10 to 20 carbon atoms, as well as combinations thereof. Some commercially available trimerization catalysts include, among others, DABCO® TMR-2, DABCO® TMR-20, DABCO® TMR-30, DABCO® TMR-7, DABCO® K2097; DABCO® K15, POLYCAT® 41, and POLYCAT® 46, all of which are available from Evonik.

[0031] The catalyst may include a "latent catalyst" or "delayed catalyst," which is defined as a catalytic compound that has low catalytic activity or is relatively inert at ambient temperature, but becomes more catalytically active upon heating through dissociation, decoupling, ring-opening, ionization, or tautomerization, thereby catalyzing at least one of the chemical reactions involved in the production of PU foam. The ambient temperature can be in the range of 15°C to 35°C, and room temperature is often around 23°C.

[0032] Latent / delayed catalysts may be gelling, foaming, and / or trimerizing catalysts in relation to their function in foaming processes. Latent catalysts are often a subset of tertiary amine gelling catalysts, including acidic salts, phenolic salts, or complexes of tertiary amine catalysts (e.g., delayed-acting tertiary amines based on 1,8-diazabicyclo[5.4.0]undeca-7-ene), and the acids or phenols are often, but not limited to, carboxylic acids or phenol species such as formic acid, acetic acid, propionic acid, 2-ethylhexanoic acid, phenoxyacetic acid, gluconic acid, tartaric acid, citric acid, phenol, nonylphenol, diisopropylphenol, and mixtures thereof. Some commercially available latent catalysts include, for example, DABCO® TMR-30, POLYCAT® SA2 LE, POLYCAT® SA-1 / 10, and DABCO® 8154 from Evonik; NIAX® A-107, NIAX® C-31, and NIAX® C-225 from Momentive; and JEFFCAT® ZF-54, JEFFCAT® LED-204 from Huntsman Corporation; and mixtures thereof.

[0033] The catalyst or catalyst package may be present in the PU composition in a weight percentage (W%) ranging from 0.1% to 10% or from 1% to 7%. In some cases, the catalyst package may be added to the isocyanate-reactive component in an amount sufficient to provide a mixture having the corresponding weight percentages mentioned above.

[0034] A polyurethane composition may contain one or more hollow particles that can modify its physical properties, introduce void volume, and reduce its overall density. Hollow particles and mixtures may be added to one or more isocyanate components and / or isocyanate-reactive components, or as a third component in a combination of isocyanate components and isocyanate-reactive components. In some cases, hollow particles may be added to multiple components to improve viscosity matching and promote homogeneous mixing.

[0035] The hollow particles may include hollow shell particles or porous aerogels composed of glass, ceramic, silica, etc. The hollow particles may have different shapes and geometries such as spheres, hemispheres, tubes, elongated, rectangular, elliptical, etc. The hollow particles may have a density in the range of 0.05 g / mL to 0.8 g / mL, or 0.10 g / mL to 0.6 g / mL. The hollow particles may have a particle size and particle distribution in the range of 1 to 350 microns, or 1 to 300 microns, or 1 to 250 microns.

[0036] In some cases, the surface of the hollow particles can be modified to mediate the interaction between the particles and the surrounding matrix and / or polymer phase, such as by adjusting hydrophobicity or hydrophilicity. Surface modification may include covalent and ionic bond chemistries for attaching functional groups such as alkyl chains, siloxanes, hydroxyl groups, amines, thiols, isocyanates, epoxies, acrylates, aromatics, etc. For example, surface modification may include the use of silane chemistry including organosilanes having the formula R (4-n) Si(OR 2 ) n wherein R is an alkyl or substituted alkyl group having 1 to 20 carbon atoms (e.g., substituted with the above functional groups), and n is an integer from 2 to 4. Examples of organosilanes include dimethoxydimethylsilane, dimethoxydiethylsilane, diethoxydimethylsilane; trimethoxymethylsilane, trimethoxyethylsilane, trimethoxypropylsilane, triethoxymethylsilane, triethoxyethylsilane, aminopropyltriethoxysilane, (3-glycidyloxypropyl)trimethoxysilane, methacryloxypropyltrimethoxysilane, and vinyltriethoxysilane.

[0037] In some cases, the hollow particles may include glass particles having a density in the range of 0.1 g / mL to 0.6 g / mL and having an organosilane (e.g., epoxy silane) surface modification.

[0038] The polyurethane composition may contain one or more hollow particles in weight percentage (W%) ranging from 0.5% to 35% by weight, 1% to 25% by weight, or 1% to 20% by weight.

[0039] Polyurethane compositions may contain one or more flame retardants (also known as FR (flame retardant) or FR additives) to improve flame retardancy. Suitable flame retardants include, in particular, carbon black, aluminum hydroxide hydrate, silicates such as wollastonite, platinum and platinum compounds, carbonates such as calcium carbonate, red phosphorus, and sodium citrate. Alternatively, the flame retardant may be at least one of halogenated flame retardants, such as decabromodiphenyl oxide, octabromodiphenyl oxide, hexabromocyclododecane, decabromobiphenyl oxide, diphenyloxybenzene, ethylenebis-tetrabromophthalamide, pentabromoethylbenzene, pentabromobenzyl acrylate, tribromophenylmaleimide, tetrabromobisphenyl A, bis-(tribromophenoxy)ethane, bis-(pentabromphenoxy)ethane, polydibromophenylene oxide, tribromophenylaryl ether, bis-dibromopropyl ether, tetrabromophthalic anhydride, dibromoneopentyl glycol, dibromoethyldibromocyclohexane, pentabromodiphenyl oxide, tribromostyrene, pentabromochlorocyclohexane, tetrabromoxylen, hexabromocyclododecane, brominated polystyrene, tetradecabromodifenoxybenzene, trifluoropropene, and PVC. Alternatively, the flame retardant may be at least one of the following: phosphorus-based flame retardants, e.g., (2,3-dibromopropyl)-phosphate, phosphorus, cyclic phosphate, triaryl phosphate, bis-melaminium pentate, pentaerythritol dicyclic phosphate, dimethylmethyl phosphate, phosphine oxide diol, triphenyl phosphate, tris(2-chloroethyl) phosphate, trichloropropyl phosphate, triethyl phosphate, phosphate esters, e.g., tricresyl phosphate, trixylenyl phosphate, isodecyl diphenyl phosphate, ethylhexyl diphenyl phosphate, isopropylated triphenyl phosphate, t-butylated triphenyl phosphate, i-butylated triphenyl phosphate, and mixtures thereof.Alternatively, phosphate salts of various amines such as ammonium polyphosphate, trioctyl, tributyl, or tris-butoxyethyl phosphate, and alkyl phosphate oligomers. Other flame retardants may include derivatives such as melamine and melamine salts, guanidine, dicyandiamide, ammonium sulfamate, alumina trihydrate, and magnesium hydroxide. FR additives may also include copolymer polyols such as polyisocyanate polyaddition (PIPA) polyols or polyurea polyols, which are produced by reacting a low equivalent polyol (e.g., up to 80 hydroxyl equivalents) or polyamine with a polyisocyanate in the presence of a base polyol continuous phase (e.g., a homopolymer or copolymer of propylene oxide and / or ethylene oxide having at least 200 hydroxyl equivalents).

[0040] The amount of flame retardant may vary depending on factors such as the selected flame retardant and the intended use of the polyurethane composition to achieve UL-94 vertical combustion performance of V2 or higher, more preferably V1 or higher, and most preferably V0. The flame retardant and mixture may be added to one or more of the isocyanate components and / or isocyanate reactive components. The amount of flame retardant in the polyurethane composition may depend on the specific flame retardant used, and if present, may typically range from 5% to 60% by weight, or from 5% to 60% by weight, based on the total weight of the polyurethane composition.

[0041] The PU composition may contain one or more silicones or organic defoamers in a weight percentage (wt%) of the polyurethane composition ranging from 0.05% to 5% by weight, 0.1% to 1.5% by weight, or 0.1% to 1% by weight.

[0042] The polyurethane composition may contain one or more fillers, including glass fibers, fibers, carbon fiber silica, CaCO3, kaolin, talc, alumina, alumina trihydrate (ATH), etc. One or more fillers may be added to the composition in a weight percentage (W%) ranging from 0% to 25% or from 1% to 20%. In some cases, the fillers may be added to the isocyanate component and / or isocyanate-reactive component in an amount sufficient to provide a mixture having the corresponding weight percentages described above.

[0043] The isocyanate-reactive component may also contain one or more additives, including blowing agents, surfactants, crosslinking agents, plasticizers, smoke suppressants, fragrances, strengthening agents, dyes, colorants, pigments, preservatives, odor masks, physical blowing agents, chemical blowing agents, flame retardants, internal release agents, biocides, antioxidants, UV stabilizers, antistatic agents, thixotropes, adhesion promoters, and bubble release agents. When reacting in the presence of an amine catalyst and isocyanate, additional amounts of epoxy resin may also be used to increase the thermosetting glass transition temperature. Examples include DER383 and DER354 from Olin Corporation.

[0044] Although the formulation components are disclosed individually, it is assumed that component elements (e.g., compounds in isocyanates or isocyanate-reactive components) may be included, excluded, or combined in any manner or in any partial combination, utilizing either the above concentration range or nested partial ranges therewith.

[0045] The PU compositions disclosed herein may have flame retardancy of V2 or higher, or V1 or higher, in vertical combustion at 5 mm according to the UL94 standard.

[0046] PU compositions may have thermal conductivity suitable for their intended application. In some cases, such as automotive applications, the thermal conductivity may be 0.2 W / mK or less, while in other applications, it may be higher, such as 0.5 W / mK, 0.4 W / mK, or 0.3 W / mK or less.

[0047] The PU composition may have a density of less than 1 g / mL, or in the range of 0.2 g / mL to 2.0 g / mL, or 0.3 g / mL to 1.5 g / mL, or 0.6 g / mL to 1.5 g / mL, 0.65 g / mL to 1.5 g / mL, or 0.7 g / mL to 1.5 g / mL, according to ASTM D3574-17 Test A.

[0048] The PU composition may have a viscosity of less than 1500 cP after 6 seconds, less than 2500 cP after 2 minutes, and less than 3500 cP after 5 minutes when the components are mixed.

[0049] While the formulation components and properties are disclosed individually, it is assumed that component elements (e.g., compounds in isocyanates or isocyanate-reactive components) may be included, excluded, or combined in any manner or in any partial combination, utilizing either the above concentration ranges or nested partial ranges therewith. Furthermore, the listed formulation properties can similarly be achieved by various combinations of the listed components within the listed ranges.

[0050] PU compositions can generally be formed by combining an isocyanate component and an isocyanate-reactive component (and an optional third component containing, for example, hollow particles) to form a mixture by a preferred method (e.g., static mixing, dynamic mixing, dynamic and static mixing, high-speed mixing, low-pressure mixing, overhead mixing by an impeller or paint mixer, impact mixing, etc.), and reacting the mixture to form a PU article. PU compositions can be used in any preferred process for developing articles and composites, including molding, injection molding, vacuum injection, etc. Methods may include applying the PU composition to a substrate by distributing or coating using spin coating, brush coating; drop coating; spray coating; dip coating; roll coating; flow coating; slot coating; gravure coating; Meyer bar coating, etc. In some cases, methods may include combining an isocyanate component and an isocyanate-reactive component to form a mixture, applying the mixture to a substrate, and reacting the mixture to form a polyurethane article or composite (e.g., a coating, encapsulant, potent). The PU composition may be formed by distributing, injecting, and / or spraying it into and / or onto one or more specific locations in a battery pack or module using a process suitable for battery pack / module assemblies to achieve complete (or partial) sealing of the battery cells.

[0051] The method may include preparing a polyurethane composition by combining an isocyanate component and an isocyanate-reactive component to form a mixture, and then reacting the mixture to form a polyurethane composition. A composite article may be prepared by distributing the composition onto a substrate and curing the composition to produce a composite article containing the polyurethane article on the substrate. In some cases, the substrate may define at least one void, and distributing may include arranging the composition within at least one void such that the polyurethane article is located within the void of the composite article. For example, the substrate may include a battery cell, a surface, or a component, and the composite article may include a battery pack and / or module. However, the composition polyurethane article may be used as a potent or sealant in end uses other than battery packs, such as for electrical circuits, and in other end uses, including for purposes other than potent and / or sealant.

[0052] The PU compositions disclosed herein may be used as potents or thermal barriers for electrical, battery pack, and / or module-related applications. Potents may coat, encapsulate (completely or partially) electrical connections and / or protect them from abusive environments such as heat, cold, flame, weather elements, dust (e.g., sand or dirt particles), physical shock or vibration, or other abusive elements. The amount of potent used may range from a minimum sufficient to coat and protect electrical connections to a maximum sufficient to fill voids in battery cells, junction boxes, etc. PU compositions may also be applied to fixed energy storage applications in personal and commercial environments. While PU compositions may be formulated to meet the constraints for automotive and mobility solutions (e.g., EVs), they may be modified outside the scope of those constraints for other related electrical and fixed energy storage applications. For example, fixed storage applications may be formulated with higher densities / weight (greater than 1 g / mL) and higher thermal conductivity (e.g., greater than 0.2 W / mK), where overall weight and lack of external cooling are not driving factors.

[0053] The PU compositions disclosed herein may include a multilayer composition containing a first layer of thermosetting resin, wherein a second layer (or capping layer) is deposited on the first layer and contains the PU composition disclosed herein. The multilayer composition may also include capping layers deposited on two or more lower layers. In some cases, the multilayer composition may include a first layer (or more layers) occupying a volume percentage (vol%) of 1 vol% to 70 vol% or 1 vol% to 30 vol% of the multilayer composition, with the remainder being the PU composition disclosed herein. In some cases, the first layer (or more layers) of thermosetting resin may be deposited on a substrate such as between battery cells in a battery assembly, and then a second layer containing the PU composition disclosed herein may be added thereto.

[0054] The PU composition used for the first layer (or one of several first layers) in contact with the substrate may include a thermosetting resin such as polyurethane, which is prepared using any of the above components and additives, and may include a foam-forming PU composition containing one or more blowing agents, epoxy, phenol, polyester, polyamide, silicone, or a combination thereof. The blowing agent may include water and aqueous fluids; chemical blowing agents such as hydrocarbons, hydrofluoroolefins, hydrofluorocarbons, acids, and volatile organic compounds; and physical blowing agents such as gases such as nitrogen, air, and carbon dioxide. The blowing agent may be added to the isocyanate reactive component in a weight percentage (wt%) of 0.1% to 7% or 0.1% to 4%. The blowing agent may be added to and / or during the mixing in an amount sufficient to provide a mixture having the corresponding weight percentages described above.

[0055] The first layer (or one of several first layers) may or may not be evaluated for fire resistance or flame retardancy during UL-94 vertical or horizontal combustion tests at a thickness of 10 mm or less. The first layer (or one of several first layers) may have a thermal conductivity value of less than 0.25 W / mK or less than 0.30 W / mK according to ISO 22007-2. The first layer (or one of several first layers) may be flexible or rigid depending on the composition from the above description, and its modulus of elasticity (E') according to ASTM D638-03 is in the range of 5 to 1000 MPa. In some cases, thermosetting resins had a thermal conductivity value of less than 0.25 W / mK and a modulus of elasticity in the range of 5 to 1000 MPa.

[0056] While the formulation components and properties are disclosed individually, it is assumed that component elements (e.g., compounds in isocyanates or isocyanate-reactive components) may be included, excluded, or combined in any manner or in any partial combination, utilizing either the above concentration ranges or nested partial ranges therewith. Furthermore, the listed formulation properties can similarly be achieved by various combinations of the listed components within the listed ranges.

[0057] The numerical ranges disclosed herein include all values ​​from the lower limit to the upper limit (including these), and all values ​​in between. Unless otherwise stated, unless implicitly stated in the context, or unless customary in the art, all parts and percentages are based on weight. Unless otherwise specified, all standardized test methods utilize the most current standards as of the filing date of this disclosure. [Examples]

[0058] The following embodiments are provided to illustrate embodiments of the present invention, but are not intended to limit their scope. Table 1 provides the materials used in the following embodiments.

[0059] [Table 1]

[0060] Example 1: Properties of the polyurethane composition In this example, a sample of the present invention containing a polyurethane composition was tested for its physical properties compared to a comparative example that did not contain hollow particles. The sample formulations are shown in Table 2 (comparative) and Table 3 (present invention).

[0061] The total content of all isocyanate-reactive components from Tables 2 and 3 was weighed using an analytical balance according to the formulation requirements (polyols, additives, and catalysts), and mixed using a DAC 600.1 FVZ-K speed mixer until dispersed. Pre-blended batches were used within 2 hours of mixing; for later use, pre-mixing was performed to avoid phase separation. If hollow particles were present, they were added to the isocyanate-reactive components and rapidly mixed before being used in the formulation.

[0062] Next, the corresponding isocyanate component was added to the isocyanate-reactive component in an appropriate ratio and rapidly mixed, then placed in a rectangular metal mold at room temperature (20-25°C). The dimensions of the metal mold were 19 cm in length and 12.5 cm in width (the thickness was set to 2 mm for mechanical properties, and the 12.5 mm thick sample was further cut to 5 mm thick for a 0.5 inch wide UL-94 vertical combustion test for flame retardancy (FR) performance measurement). Then, the cured molded plaques of the PU potent material sample were tested to determine the mechanical properties of the potent.

[0063] After removing the sample from the mold, measure the dimensions of the rectangular potent sample using a measuring scale and weigh it on a weighing balance. Calculate the density of the sample as (weight of sample) / (length × width × height).

[0064] All potent samples were removed from the mold after 30–60 minutes, cured at 60°C for 1 hour, and then tested for mechanical and thermal properties to ensure curing similar to that used in EV batteries. Some potent samples were observed to break and / or shatter and / or snap during removal from the mold or during punching out the dogbone shape, and were classified as "untestable" due to their brittleness.

[0065] [Table 2]

[0066] [Table 3]

[0067] Next, the sample formulations were tested for several physical characteristics (1) to (13) listed below. The test results for each formulation are shown in Tables 4 and 5.

[0068] UL94 Vertical Combustion Test (1): Potent material prepared in a metal mold to a thickness of 12.7 mm was then cut to a thickness of 5 mm with dimensions of 0.5 inches and 10 cm or more using the procedure described above. The pre-prepared potent samples (potent alone) were tested according to the UL94 Vertical Combustion Protocol, and their performance was classified into the appropriate category - V0 (best and desired performance), V1, V2, and Fail (Fail means that the potent sample burns completely to the clamp during and / or after flame exposure).

[0069] Thermal conductivity (2): Using a Hot Disk AB TPS 2500S instrument equipped with a Kapton insulated 5465 F1 sensor, the thermal conductivity of a 2 mm thick pre-cured potent sample was measured in accordance with ISO 22007-2 using an isotropic (standard) module with a heating power of 50 mW, a measurement time of 5 seconds, and standard analysis. A 2 mm thick potent plaque for testing was prepared using the procedure described above.

[0070] Density (3): Calculated as the density (i.e., weight / volume) of the hardened potent plaque sample, performed according to ASTM D3574-17 Test A. Plaque weight was measured in grams, and plaque height was measured in cm. The width and thickness of the plaque were 12.5 cm and 0.2 cm, respectively. Density of potent sample (g / cm³) 3 (or g / mL): Weight of potent sample × 1000 / (height × 12.5 × 0.2).

[0071] Viscosity (4-6): The fluidity of potent materials in actual composite battery assemblies was quantified using polyol + isocyanate reactive viscosity measurements with a TA Instruments AREG G2. A 50 mm conical-plate geometric shape made from stainless steel was used. The pre-blended polyol side (with or without pre-mixed air bubbles according to the formulation) was placed in a speed mixer cup (up to 20 cups), and the appropriate amount and type of isocyanate was added thereto (according to the formulations in Table 4). The formulations were mixed at 2100 rpm for 8-10 seconds, the appropriate amount of liquid was poured onto the AREG G2 rheometer plate (within 3-4 seconds after mixing was complete), the gap was set to 2 mm (excess was wiped off with a q-tip), and the measurement was started as quickly as possible (within 3-5 seconds after addition to the plate). The measurement temperature was set to 25°C ± 2°C, the vibration strain to 5%, and the angular frequency to 10 rad / sec. The measurement was continued for a minimum of 5 minutes. The viscosity of the reactants at the first data point (t=6 seconds), 2 minutes, and 5 minutes is reported in Tables 4 and 5.

[0072] Elastic modulus (7), ultimate tensile strength (8), elongation at break (9): For hardened potent plaque samples prepared using the above procedure, the elastic modulus (E), elongation at break (%), and ultimate tensile strength (MPa) were all obtained using an MTS machine according to ASTM D1708 standards. Microtensile samples were punched into a dogbone shape from plaques formed with a 2 mm thick metal mold. "N / A" samples (C1-C2) could not be tested because they were pulverized due to their inherent brittleness while the samples were being cut into a dogbone shape from the 2 mm thick plaque.

[0073] Shear modulus at -30°C (10), 25°C (11), 50°C (12), and 60°C (13): The shear modulus in torsional mode (physical characteristics (10)~(13)) was obtained by dynamic mechanical analysis (DMA) according to ASTM D5279-21 in an Advanced Rheometric Expansion System (ARES-G2) manufactured by TA Instruments, equipped with a liquid nitrogen environment control and a torsional rectangular fixture. From potent plaques prepared in metal molds (A and B) according to the above procedure, rectangular samples with a thickness of 2 mm were cut, and then cut into pieces with dimensions of 45 mm in length and 12.8 mm in width. The length of the samples was aligned axially with respect to the torsional axis, and the DMA experiment was performed in torsional mode. The temperature was increased from -70°C to 150°C at a rate of 3°C / min. The test frequency was 1 Hz with a torsional strain of 0.05%, the sample was kept taut under an axial tensile force of 0.098 N, and the data acquisition interval was 30 seconds per point. The output from the characterization was the storage modulus (G') in shear mode over the temperature range.

[0074] [Table 4]

[0075] [Table 5]

[0076] * The "calculated value" for sample I6 means that the value was extrapolated to the viscosity-time curve measured using a rheometer (as described above) because there was no mixing of isocyanate-3 (at the same time as all other examples), and therefore the inverse intercept was calculated.

[0077] The potent formulations provided in Tables 4 and 5 were produced without chemical or physical foaming agents, and as a result, no foaming action occurred. For C1 and C2, the non-foaming liquid hardened into a PU elastomer, but both failed the UL94 fire resistance (FR) test. For C3 and C6, the provision of an FR additive resulted in a V2 grade for C3 and a V0 grade for C6 in the UL94 vertical combustion test of a 5 mm thick potent, but the thermal conductivity values ​​increased to 0.22 and 0.27, respectively. Samples C1-C3 and C6 had a density of over 1 g / mL and a thermal conductivity exceeding 0.2 W / mK. Samples C4 and C5 incorporated hollow particles and exhibited lower thermal conductivity (less than 0.2 W / mK) and density. However, the potents failed UL-94 vertical combustion and, when mixed, had high viscosities (over 10,000 and over 8,000 cP, respectively, after 5 minutes). Therefore, C1-C6 were considered unsuitable for EV battery potents / encapsulants.

[0078] In contrast, embodiments of the present invention combining polyols, liquid FR additives, and hollow particles achieved the desired performance parameters. For I1 to I6, all samples demonstrated UL-94 V0 performance while exhibiting low viscosity values ​​acceptable for flowability in potent material applications, high mechanical strength, and a softening point above 60°C. I1 to I6 also demonstrated that all types of isocyanates 1, 2, and 3 can be used individually (or in combination) to achieve potent properties (1) to (14) with the performance required for I1 to I6.

[0079] The above describes exemplary embodiments, but other further embodiments may be devised without departing from their basic scope, the scope of which will be determined by the following claims.

Claims

1. A multilayer composition, A first layer comprising at least one thermosetting resin, It is fixed on the at least one first layer, and An isocyanate component containing one or more isocyanate compounds, An isocyanate-reactive component, One or more polyether polyols, An isocyanate-reactive component comprising one or more aliphatic polyols, A multilayer composition comprising: a second layer containing a reaction product with at least one of the isocyanate component, the isocyanate-reactive component, or a third component, and one or more hollow particles present in that component.

2. The composition according to claim 1, wherein the second layer further comprises an FR additive in an amount of 5% to 60% by weight of the second layer.

3. The composition according to claim 1, wherein the second layer has a density in the range of 0.2 g / mL to 2.0 g / mL according to ASTM D3574-17.

4. The composition according to claim 1, wherein the second layer has a density in the range of 0.7 g / mL to 1.5 g / mL according to ASTM D3574-17.

5. The composition according to any one of claims 1 to 4, wherein the hollow particles are present in the second layer in a weight percentage (weight%) of 0.5% to 35% of the polyurethane composition.

6. The composition according to any one of claims 1 to 4, wherein the hollow particles are present in the second layer in a weight percentage (weight%) of 1% to 20% by weight of the polyurethane composition.

7. A method for preparing a multilayer composition, Depositing at least one layer of thermosetting resin onto a substrate, The second layer, wherein the aforementioned second layer is An isocyanate component containing one or more isocyanate compounds, An isocyanate-reactive component, One or more polyether polyols, An isocyanate-reactive component comprising one or more aliphatic polyols, A method comprising distributing a second layer on the at least one layer of a thermosetting resin, the second layer containing a reaction product with one or more hollow particles present in at least one of the isocyanate component, the isocyanate reactive component, or a third component.

8. The method according to claim 5, wherein the substrate is a battery assembly.

9. The method according to claim 5, wherein the thermosetting resin is a polyurethane foam.

10. The method according to claim 5, wherein the thermosetting resin has a density of 0.65 g / mL or less.

11. The method according to claim 5, wherein the thermosetting resin has a thermal conductivity value of less than 0.25 W / m·K according to ISO 22007-2 and an elastic modulus in the range of 5 to 1000 MPa according to ASTM D638-03.

12. The method according to claim 5, wherein the at least one layer of the thermosetting resin occupies a range of 1 volume% to 30 volume% of the volume percentage (vol%) of the multilayer composition.

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