Polyol component, potting composition comprising same, polyurethane foam, and battery article

Abstract

The present invention relates to a polyol component, a potting composition comprising the polyol component and a polyurethane foam prepared from the potting composition. The invention also relates to a battery article comprising a foam prepared from the potting composition.

Description

Technical Field

[0001] The present invention relates to a polyol component, a potting composition comprising the polyol component, and a polyurethane foam prepared from the potting composition. The present invention also relates to a battery product comprising a foam prepared from the potting composition. Background Art

[0002] With the development of electric vehicles, automobile manufacturers tend to manufacture batteries with increasingly high energy density to extend the mileage, so the risks of battery failure and internal overheating become very critical. Polyurethane potting materials are a hot topic of research as a solution to battery "thermal runaway".

[0003] Traditional potting materials usually obtain certain flame retardant properties by adding liquid flame retardants and / or a small amount of solid flame retardants. However, they cannot meet the current requirements for higher flame retardant efficiency and flame retardant grades. Summary of the Invention

[0004] An object of the present invention is to overcome the problems of the above-mentioned prior art and provide a polyurethane potting composition with high flame retardancy.

[0005] Surprisingly, the inventors have found that the above object can be achieved by the polyol component and the polyurethane potting composition of the present invention.

[0006] In a first aspect of the present invention, there is provided a polyol component comprising the following components:

[0007] (a-1) at least one polyol reactive with isocyanate,

[0008] (a-2) a chain extender and / or a crosslinking agent,

[0009] (a-3) a blowing agent,

[0010] (a-4) optionally a catalyst,

[0011] (a-5) a solid flame retardant, and

[0012] (a-6) optionally additives and / or adjuvants,

[0013] wherein the solid flame retardant comprises a FR-1 flame retardant and a FR-2 flame retardant, the FR-1 flame retardant is a nitrogen-containing solid flame retardant, a phosphorus-containing solid flame retardant without metal, or a combination thereof, the FR-2 flame retardant is a metal organic phosphate solid flame retardant, the FR-1 flame retardant accounts for 8 to 20% by weight of the total weight of the polyol component, and the FR-2 flame retardant accounts for 5 to 25% by weight of the total weight of the polyol component.

[0014] In a second aspect of the present invention, there is provided a potting composition for a battery, which is obtained by reacting at least the following components:

[0015] An isocyanate component, which comprises:

[0016] (b-1) at least one isocyanate, and

[0017] (b-2) optionally a second flame retardant,

[0018] and a polyol component according to the first aspect of the present invention.

[0019] In a third aspect of the present invention, there is provided a battery article, comprising:

[0020] a battery cell; and

[0021] a polyurethane foam located between the battery cells, which is prepared from the potting composition according to the second aspect of the present invention.

[0022] Surprisingly, it has been found that in the present invention, the products prepared from the polyol component and the potting composition as described above exhibit high elasticity, good electrical insulation and good flame retardancy. Detailed Description

[0023] Unless otherwise defined, all technical and scientific terms used herein have the meanings commonly understood by those skilled in the art to which this invention belongs. As used herein, unless otherwise specified, the following terms have the meanings given to them below.

[0024] As used herein, the articles "a" and "an" refer to one or more than one (i.e., to at least one) grammatical object of the article. For example, "an element" refers to one element or more than one element.

[0025] As used herein, the expression "comprising" also encompasses the expression "consisting of".

[0026] Unless otherwise specified, all percentages (%) refer to "weight percentages".

[0027] Unless otherwise specified, the temperature refers to room temperature and the pressure refers to ambient pressure.

[0028] As used herein, "potting" refers to the process of filling a liquid potting composition (such as a polyurethane potting composition in the context of the present invention) into a container (such as a battery housing in the context of the present invention). The liquid potting composition poured into the container foams and cures, thereby protecting the internal components (such as battery cells in the context of the present invention) against shock and vibration and can absorb the deformation pressure generated by the deformation of surrounding components. It should be understood that the polyurethane potting composition foams freely, i.e., the foam can expand freely in at least one dimension.

[0029] In the preparation of polyurethane potting materials, an "isocyanate component" and a "polyol component" (also referred to hereinafter as "resin component" or "resin") are used, wherein the "polyol component" is a mixture of a polyol (a-1) reactive to isocyanate, a chain extender and / or crosslinking agent (a-2), a blowing agent (a-3), optionally a catalyst (a-4), a solid flame retardant (a-5), and optionally additives and / or auxiliaries (a-6), and the "isocyanate component" is a mixture of at least one isocyanate (b-1) and optionally a second flame retardant (b-2). The polyol component reacts with the isocyanate to form urethane bonds, and such systems are disclosed, for example, in U.S. Patent No. 4,218,543.

[0030] In commercial applications, the isocyanate component and the polyol component are stored separately, transported to a mixing chamber and mixed (such as static mixing or impact mixing) during use to produce a liquid polyurethane reaction mixture. Then the liquid polyurethane reaction mixture is immediately introduced into the receiving cavity of the battery article (such as by using a high-pressure or low-pressure system). There is no limitation on the type of suitable machine.

[0031] In a first aspect of the present invention, there is provided a polyol component for preparing a polyurethane potting composition. The polyol component comprises the following components:

[0032] (a-1) at least one polyol reactive to isocyanate,

[0033] (a-2) a chain extender and / or crosslinking agent,

[0034] (a-3) a blowing agent,

[0035] (a-4) optionally a catalyst,

[0036] (a-5) a solid flame retardant, and

[0037] (a-6) optionally additives and / or auxiliaries,

[0038] Among them, the solid flame retardant includes FR-1 flame retardant and FR-2 flame retardant. The FR-1 flame retardant is a nitrogen-containing solid flame retardant, a phosphorus-containing solid flame retardant without metal, or a combination thereof. The FR-2 flame retardant is a metal organic phosphate solid flame retardant. The FR-1 flame retardant accounts for 8 to 20% by weight of the total weight of the polyol component, and the FR-2 flame retardant accounts for 5 to 25% by weight of the total weight of the polyol component.

[0039] Polyol component

[0040] Polyol (a-1) reactive with isocyanate

[0041] The polyol (a-1) reactive with isocyanate can be any polyol that can be used in the preparation of polyurethanes in the art and has at least two reactive hydrogen atoms. For example, polyether polyols, polyester polyols, or mixtures thereof can be used.

[0042] The preferably used polyol is a polyether polyol. Compared with polyester polyols, polyether polyols are not easily aged in a humid and hot environment. According to the present invention, the preferably used polyether polyol has a number average molecular weight Mn of 300 to 8000, preferably 3000 to 6500, and 2 ≤ functionality (Fn) ≤ 3. The above preferably used polyether polyol has a low viscosity, which enables the polyol component to still have a low viscosity and good processability after adding the solid flame retardant. Examples of suitable commercially available polyols include 2090 (BASF), 2048 (BASF).

[0043] The polyether polyol is prepared by known methods from one or more alkylene oxides having 2 to 4 carbon atoms in the alkylene group and adding at least one initiator containing 2 to 8 reactive hydrogen atoms, for example, by anionic polymerization using an alkali metal hydroxide or an alkali metal alcoholate as a catalyst, or by cationic polymerization using a Lewis acid (such as antimony pentachloride or boron trifluoride etherate) as a catalyst. In addition, the catalyst used can also be a multi-metal cyanide - the so-called DMC catalyst.

[0044] Examples of suitable alkylene oxides include ethylene oxide, tetrahydrofuran, 1,3-propylene oxide, 1,2-propylene oxide, 1,2-butylene oxide, and 2,3-butylene oxide. The alkylene oxides can be used alone, or used in sequence alternately or mixed.

[0045] Examples of suitable initiators include water or diols and triols, such as ethylene glycol, propane-1,2-diol or propane-1,3-diol, diethylene glycol, dipropylene glycol, butane-1,4-diol, glycerol, and trimethylolpropane.

[0046] The polyol (a-1) accounts for 35% to 85% by weight, preferably 40% to 70% by weight, of the total weight of the polyol component.

[0047] Optionally, the polyether polyol used to prepare the polyurethane of the present invention further comprises a flame-retardant polyether polyol. The flame-retardant polyether polyol introduces phosphorus and halogen elements into the polyol molecular chain, thereby achieving a flame-retardant effect. The preferably used flame-retardant polyether polyol has a number-average molecular weight Mn of 300 to 8000, preferably 3000 to 6500, and 2 ≤ functionality (Fn) ≤ 4. Examples of suitable commercially available flame-retardant polyether polyols include ZR-001 from Bluestar Dongda. The flame-retardant polyether polyol used in the present invention can also be prepared by known methods. For example, they can be prepared by reacting a halogen-containing initiator with an alkylene oxide in the presence of a catalyst. The flame-retardant polyether polyol accounts for 0% to 40% by weight, preferably 5% to 20% by weight, of the total weight of the polyether polyol.

[0048] Chain extender and / or crosslinking agent (a-2)

[0049] The chain extender and / or crosslinking agent (a-2) that can be used are substances with a molar mass preferably less than 500 g / mol, particularly preferably 60 to 400 g / mol, wherein the chain extender has 2 hydrogen atoms reactive to isocyanate and the crosslinking agent has 3 hydrogen atoms reactive to isocyanate. These substances can be used alone or preferably in the form of a mixture. Diols and / or triols with a molecular weight less than 500, particularly 60 to 400, particularly 60 to 200, are preferably used. Examples of those substances that can be used are aliphatic, alicyclic and / or aralkyl diols having 2 to 14, preferably 2 to 10 carbon atoms, such as ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, 1,10-decanediol, 1,2-, 1,3- and 1,4-dihydroxycyclohexane, diethylene glycol, dipropylene glycol, tripropylene glycol, diethanolamine or triols, such as 1,2,4- or 1,3,5-trihydroxycyclohexane, glycerol and trimethylolpropane. The chain extender and / or crosslinking agent (a-4) is preferably selected from ethylene glycol, diethylene glycol, dipropylene glycol, tripropylene glycol, glycerol and 1,4-butanediol.

[0050] The chain extender and / or crosslinking agent (a-2) accounts for 1 to 10% by weight of the total weight of the polyol component.

[0051] Foaming agent (a-3)

[0052] The blowing agent (a-3) used according to the present invention preferably contains water. The blowing agent used may also contain other chemical and / or physical blowing agents in the art as well as water. Chemical blowing agents are compounds that form gaseous products by reacting with isocyanates. Examples are water or formic acid. Physical blowing agents are compounds that have been dissolved or emulsified in the starting materials used for polyurethane preparation and evaporate under the conditions of polyurethane formation. By way of example, these substances are hydrocarbons, halogenated hydrocarbons and other compounds such as perfluoroalkanes, for example perfluorohexane, chlorofluorocarbons, and ethers, esters, ketones and / or acetals. In a preferred embodiment, water is used as the sole blowing agent (a-3). In this case, the polyurethane foam according to the present invention is a water-blown polyurethane foam.

[0053] The blowing agent (a-3) accounts for 0.1 to 4% by weight, preferably 0.2 to 1% by weight, of the total weight of the polyol component.

[0054] Catalyst (a-4)

[0055] As the catalyst (a-4), such compounds are known and are described, for example, in "Kunststoffhandbuch, Volume 7, Polyurethane", Carl Hanser Verlag, 3rd edition, 1993, Chapter 3.4.1. These substances include amine-based catalysts and catalysts based on organometallic compounds.

[0056] As catalysts based on organometallic compounds, for example, organotin compounds such as tin(II) salts of organic carboxylic acids, such as tin(II) acetate, tin(II) octoate, tin(II) ethylhexanoate and tin(II) laurate, and dialkyltin(IV) salts of organic carboxylic acids, such as dibutyltin diacetate, dibutyltin dilaurate, dibutyltin maleate and dioctyltin diacetate, and bismuth carboxylates, such as bismuth(III) neodecanoate, bismuth 2-ethylhexanoate and bismuth octoate, or alkali metal salts of carboxylic acids, such as potassium acetate or potassium formate, can be used.

[0057] Preferably, an amine-based catalyst is used as the catalyst (a-4), such as N,N,N',N'-tetramethyldipropylenetriamine, 2-[2-(dimethylamino)ethyl-methylamino]ethanol, N,N,N'-trimethyl-N'-2-hydroxyethyl-bis-(aminoethyl)ether, bis(2-dimethylaminoethyl)ether, N,N,N,N,N-pentamethyldiethylenetriamine, N,N,N-triethylaminoethoxyethanol, dimethylcyclohexylamine, trimethylolethylenediamine, dimethylbenzylamine, triethylamine, triethylenediamine, pentamethyldipropylenetriamine, dimethylethanolamine, N-methylimidazole, N-ethylimidazole, tetramethylhexamethylenediamine, tris(dimethylaminopropyl)hexahydrotriazine, dimethylaminopropylamine, N-ethylmorpholine, diazabicycloundecene, and diazabicyclononene. Examples of suitable commercially available amine catalysts include Dabco 33LV.

[0058] The catalyst (a-4) accounts for 0 to 5% by weight, preferably 0.1 to 3.5% by weight, of the total weight of the polyol component.

[0059] Solid flame retardant (a-5)

[0060] The solid flame retardant (a-5) suitable for the present invention comprises a FR-1 flame retardant and a FR-2 flame retardant. The FR-1 flame retardant is a nitrogen-containing solid flame retardant, a metal-free phosphorus-containing solid flame retardant, or a combination thereof. The FR-2 flame retardant is a metal-organic phosphate solid flame retardant. Compared with liquid flame retardants and single solid flame retardants, the combination of solid flame retardants according to the present invention can achieve higher flame retardancy efficiency and flame retardancy grade.

[0061] Specific examples of nitrogen-containing solid flame retardants include melamine, melamine salts, guanidine, melamine cyanurate (MCA), melamine polyphosphate (MPP), melamine phosphate, melamine formaldehyde, hydroxymethylated melamine, hexamethoxymethyl melamine, urea, dimethylurea, melamine pyrophosphate, dicyandiamide, guanylurea phosphate, and glycine. Preferably, melamine and its derivatives (such as melamine cyanurate, melamine polyphosphate, melamine phosphate, etc.) are used.

[0062] The metal-free phosphorus-containing solid flame retardants include at least one selected from the following: 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO), triphenyl phosphate, ammonium polyphosphate, red phosphorus, tributyl phosphate (RBP), and mixtures thereof.

[0063] The FR-1 flame retardant accounts for 8 to 20% by weight of the total weight of the polyol component. For example, the FR-1 flame retardant may account for 8% by weight, 9% by weight, 10% by weight, 11% by weight, 12% by weight, 13% by weight, 14% by weight, 15% by weight, 16% by weight, 17% by weight, 18% by weight, 19% by weight, or 20% by weight, etc. of the total weight of the polyol component. In one embodiment, the particle size D95 of the FR-1 flame retardant is ≤60 μm, preferably ≤40 μm, more preferably ≤25 μm.

[0064] The metal-organic phosphate solid flame retardant comprises at least one selected from the following: metal salts of phosphoric acid, phosphonic acid, or hypophosphorous acid, wherein the metal is selected from iron, aluminum, magnesium, zinc, lanthanum, cerium, etc. The metal-organic phosphate solid flame retardant (FR-2 flame retardant) accounts for 5 to 25% by weight of the total weight of the polyol component. For example, the metal-organic phosphate solid flame retardant (FR-2 flame retardant) may account for 5% by weight, 6% by weight, 7% by weight, 8% by weight, 9% by weight, 10% by weight, 11% by weight, 12% by weight, 13% by weight, 14% by weight, 15% by weight, 16% by weight, 17% by weight, 18% by weight, 19% by weight, 20% by weight, 21% by weight, 22% by weight, 23% by weight, 24% by weight, or 25% by weight, etc. of the total weight of the polyol component. In one embodiment, the particle size D95 of the FR-2 flame retardant is ≤120 μm, preferably ≤60 μm.

[0065] Preferably, the weight ratio of the FR-2 flame retardant to the FR-1 flame retardant is 3:1 to 1:4. For example, the weight ratio of the FR-2 flame retardant to the FR-1 flame retardant can be 3:1, 2:1, 1:1, 1:2, 1:3, or 1:4, etc.

[0066] The preferably used metal-organic phosphate solid flame retardant is an organic hypophosphite metal salt having the following formula:

[0067]

[0068] R 1 , R 2 are the same or different and represent a straight-chain or branched C1-C6 alkyl group (more preferably a C1-C4 alkyl group);

[0069] M represents Al, Mg, Ca, Sb, Sn, Ge, Ti, Fe, Zr, Zn, Ce, Bi, Sr, Mn, Li, Na, K;

[0070] m represents 1, 2, 3, or 4.

[0071] Preferably, the metal organic hypophosphite is selected from aluminum diethyl hypophosphite, aluminum methyl ethyl hypophosphite, aluminum dipropyl hypophosphite, aluminum dibutyl hypophosphite, aluminum ethyl butyl hypophosphite, aluminum ethyl hexyl hypophosphite, aluminum butyl hexyl hypophosphite, and mixtures thereof.

[0072] Specific examples of the metal organic phosphate solid flame retardant also include iron phenyl phosphate (PPFe), aluminum phenyl phosphate (PPAl), zinc phenyl phosphate (PPZn), triphenyl iron phosphate (PP3Fe2), and phenyl phosphoric acid iron (PHA-Fe).

[0073] In a preferred embodiment, the solid flame retardant (a-5) of the present invention does not contain expandable graphite. This gives the polyurethane foam of the present invention higher electrical insulation.

[0074] In one embodiment, the total amount of the solid flame retardant (a-5) is preferably 13 to 45% by weight, more preferably 25 to 40% by weight, based on the total weight of the polyol component.

[0075] Additives and / or auxiliaries (a-6)

[0076] The additives and / or auxiliaries (a-6) that can be used include but are not limited to surfactants, preservatives, colorants, antioxidants, reinforcing agents, stabilizers, and water absorbents. When preparing polyurethane foam, it is generally preferred to use a small amount of surfactant to stabilize the foaming reaction mixture until it cures. Such surfactants advantageously include liquid or solid silicone surfactants in an amount sufficient to stabilize the foaming reaction mixture. Generally, the amount of the auxiliary, especially the surfactant, is 0.5 to 5% by weight, based on the total weight of the polyol component.

[0077] Further information on the use and mode of action of the above-mentioned auxiliaries and additives, as well as additional examples, are given, for example, in "Kunststoffhandbuch, Band 7, Polyurethane" ["Plastics handbook, Volume 7, Polyurethanes"], Carl Hanser Verlag, 3rd edition, 1993, Chapter 3.4.

[0078] The viscosity of the polyol component according to the present invention is 500 to 6000 mPa·s, which is measured according to ASTM D2196-15.

[0079] In a second aspect of the present invention, there is provided a potting composition obtained by reacting at least the following components:

[0080] An isocyanate component, which comprises:

[0081] (b-1) at least one isocyanate, and

[0082] (b-2) Optionally, a second flame retardant

[0083] The polyol component according to the first aspect of the present invention.

[0084] Isocyanate component

[0085] Isocyanate (b-1)

[0086] The present invention places no restrictions on the type of polyisocyanate, which refers to an organic compound containing more than two active isocyanate groups per molecule, i.e., a functionality of 2 (in which case the polyisocyanate is also referred to as a diisocyanate) or greater than 2. Examples of isocyanates can include any aliphatic, alicyclic, araliphatic, and aromatic difunctional or polyfunctional isocyanates known in the prior art and any desired mixtures thereof. The isocyanate can be a monomer, a prepolymer, and / or a polymeric isocyanate.

[0087] Suitable examples include aliphatic, alicyclic, araliphatic, and / or aromatic isocyanates such as tri-, tetra-, penta-, hexa-, hepta-, and / or octamethylene diisocyanate, 2-methylpentamethylene 1,5-diisocyanate, 2-ethylbutylene 1,4-diisocyanate, pentamethylene 1,5-diisocyanate, butylene 1,4-diisocyanate, 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (isophorone diisocyanate, IPDI), 1,4- and / or 1,3-bis(isocyanatomethyl)cyclohexane (HXDI), cyclohexane 1,4-diisocyanate, 1-methylcyclohexane 2,4- and / or 2,6-diisocyanate, and / or dicyclohexylmethane 4,4’- / 2,4’- and 2,2’-diisocyanate, diphenylmethane 2,2'-, 2,4’-, and / or 4,4’-diisocyanate (MDI), polymeric MDI, naphthylene 1,5-diisocyanate (NDI), toluene 2,4- and / or 2,6-diisocyanate (TDI), 3,3’-dimethyl diphenyl diisocyanate, 1,2-diphenylethane diisocyanate, and / or phenylene diisocyanate. Particular preference is given to the use of 2,2’-, 2,4’-, and / or 4,4’-diisocyanate and polymeric MDI. Examples of suitable commercially available isocyanate compounds include M20S (from BASF) or MIPS (from BASF).

[0088] Other possible isocyanates are given, for example, in "Kunststoffhandbuch, Band 7, Polyurethane" [Plastics handbook, Volume 7, Polyurethanes], Carl Hanser Verlag, 3rd edition, 1993, Chapters 3.2 and 3.3.2.

[0089] In addition, the isocyanate component can also be used in the form of an isocyanate prepolymer. The isocyanate prepolymer can be obtained by reacting the above-mentioned isocyanate with a polyol.

[0090] According to the present invention, preferably, the NCO content of the isocyanate is in the range of 12 to 35, based on the parts by weight of the isocyanate component, and Fn ≥ 2. The isocyanate accounts for 60% to 100% by weight, preferably 65% to 95% by weight, more preferably 80% to 95% by weight of the total weight of the isocyanate component.

[0091] Flame retardant (b-2)

[0092] The isocyanate component optionally contains a second flame retardant. The second flame retardant contains at least one liquid flame retardant selected from the following: for example, organophosphorus flame retardants such as resorcinol bis(diphenyl) phosphate (RDP), tris(1-chloro-2-propyl) phosphate (TCPP), tricresyl phosphate (TCP).

[0093] Optionally, the isocyanate component can also contain the nitrogen-containing solid flame retardant, metal-free phosphorus-containing solid flame retardant, and / or metal-organic phosphate solid flame retardant mentioned in the polyol component.

[0094] According to the present invention, the flame retardant (b-2) accounts for 0% to 40% by weight, preferably 5% to 35% by weight, more preferably 5% to 20% by weight of the total weight of the isocyanate component.

[0095] According to the present invention, the polyol component and the isocyanate component are mixed in a weight ratio of 100:(30 - 100), for example, 100:30, 100:40, 100:50, 100:60, 100:70, 100:80, 100:90, or 100:100; preferably 100:(40 - 90).

[0096] In the third aspect of the present invention, a battery product is provided, which includes:

[0097] Battery cells; and

[0098] A polyurethane foam located between the battery cells, which is prepared from the potting composition according to the second aspect of the present invention.

[0099] The battery product can be prepared by the following steps:

[0100] 1) Inject the potting composition described in the second aspect of the present invention into the cavity between the battery cells;

[0101] 2) Keep it cured for 10 - 60 minutes at a temperature of, for example, 10 - 35°C.

[0102] The present invention does not particularly limit the type of battery cells. For example, the assembled type of battery cells can be cylindrical batteries, soft-pack batteries, square batteries, or blade batteries. It should be understood that in addition to the battery cells, the battery product according to the present invention further includes other components such as a BMS battery management system.

[0103] In step 1), the injection can be continuous or discontinuous.

[0104] In order to fill the chambers of the battery product as much as possible within a short time range, the inventors of the present invention found that the potting composition should have good fluidity. According to the present invention, the potting composition (i.e., the liquid polyurethane reaction mixture) has an initial viscosity lower than 7000 mPa·s, preferably lower than 5000 mPa·s, at a temperature of 25°C, which is measured according to ASTM D2196 - 15. The initial viscosity of the polyurethane reaction mixture is measured as follows: Immediately after mixing the polyol component and the isocyanate component, the viscosity of the resulting polyurethane reaction mixture is measured at a temperature of 25°C according to ASTM D2196 - 15. The inventors of the present invention found that the potting composition with this initial viscosity has good fluidity and processing performance, allowing the potting composition to quickly fill cavities with complex shapes. At the same time, the good fluidity also facilitates the leveling of the potting composition within a short time.

[0105] In step 2), the potting composition is cured for 10 - 60 minutes, preferably 5 - 30 minutes, at a temperature of 10 - 35°C, preferably 15 - 25°C. The temperature is selected such that the entire curing process can be completed within a short time, which is industrially advantageous.

[0106] In one embodiment, the surface hardness of the polyurethane foam according to the present invention is not higher than 80 Shore A, preferably not higher than 65 Shore A, and more preferably not higher than 55 Shore A. That is to say, the polyurethane foam according to the present invention is a "soft foam", which enables it to effectively absorb the surrounding deformation pressure and protect the internal battery cells, etc.

[0107] In one embodiment, the dielectric strength of the polyurethane foam according to the present invention is greater than 4 kV / mm; the volume resistivity of the polyurethane potting foam is greater than 1×10 11 Ω·cm, preferably greater than 1×10 12 Ω·cm. This shows that the polyurethane foam of the present invention has good electrical insulation.

[0108] In one embodiment, the polyurethane foam according to the present invention has a flame retardancy measured according to the UL 94 test of at least V2 or higher rating. In one embodiment, the polyurethane encapsulating foam has a flame retardancy of at least V1 or higher rating measured according to the UL 94 test. In one embodiment, the polyurethane encapsulating foam has a flame retardancy of V0 rating measured according to the UL 94 test.

[0109] In one embodiment, the polyurethane foam according to the present invention has a modulus of less than 25 MPa, preferably less than 20 MPa, more preferably less than 10 MPa measured according to ISO1798; the elongation at break of the polyurethane encapsulating foam is greater than 5%, preferably greater than 10%, more preferably greater than 20%; the tensile strength of the polyurethane encapsulating foam is 0.8 - 2.5 MPa, preferably 1 - 2 MPa.

[0110] In one embodiment, the density of the polyurethane foam according to the present invention is 0.1 - 0.4 g / cm 3 , preferably 0.2 - 0.3 g / cm 3 .

[0111] It should be noted that throughout the application, the materials mentioned in the method embodiments have the same meaning as those in the product embodiments, and each of the general, preferred, more preferred, and most preferred definitions and amounts of materials described in the product section also applies to the method of preparing the product and the articles made from the product, unless otherwise specified.

[0112] Example

[0113] The present invention will now be described with reference to examples and comparative examples, which are not intended to limit the present invention.

[0114] General description

[0115] In the examples, the following starting materials were used:

[0116]

[0117]

[0118] The following methods were used to determine the properties:

[0119]

[0120] Preparation example of potting composition

[0121] The polyol components and isocyanate components of Examples 1-9 and Comparative Examples 1-7 were prepared by mixing the corresponding components according to Table 1 and stored in separate containers. At the time of use, the two components were fed into a mixing chamber at 150 bar at the mixing ratios shown in Table 1 and impinged and mixed to produce a liquid polyurethane reaction mixture (i.e., the potting composition). The initial viscosities of the resulting liquid polyurethane reaction mixtures of Examples 1-9 and Comparative Examples 1-7 are also listed in Table 1.

[0122] As shown in Table 1, the initial viscosities of the liquid polyurethane reaction mixtures of Examples 1-9 were 1650 - 6900 mPa·s, which gave the resulting liquid polyurethane reaction mixtures the desired fluidity.

[0123] In contrast, the initial viscosity of the liquid polyurethane reaction mixture of Comparative Example 2 was 8600 mPa·s, which was too viscous to have sufficient fluidity to level.

[0124] Preparation example of battery product

[0125] The battery product includes a battery housing and has dimensions of 150 cm (width) × 150 cm (length) × 15 cm (height). The battery cells are placed inside the battery housing, i.e., on the bottom of the battery housing. The battery product further includes other components. The battery cells and other components divide the internal space of the battery housing into a plurality of receiving cavities.

[0126] The polyol component A and isocyanate component B of Examples 1-9 and Comparative Examples 1-7 were prepared according to the amounts (in weight %) shown in Table 1 below. The polyol component A and isocyanate component B were mixed according to the ratio of A:B shown in Table 1 below to obtain a liquid polyurethane reaction mixture. The liquid polyurethane reaction mixture was injected into the receiving cavities. The volumes of the liquid polyurethane reaction mixtures injected in the examples and comparative examples were the same.

[0127] After injection, the battery pack was held at room temperature (25 °C) for curing. The liquid polyurethane reaction mixture gradually cured into a polyurethane foam.

[0128]

[0129]

[0130] The flame retardant properties of the polyurethane foams obtained in Examples 1-9 and Comparative Examples 1-7 were measured. As shown in Table 1, the polyurethane foams of Examples 1-9 had a flame retardancy measured according to the UL 94 test of at least V2 or even higher grades (i.e., V1 and V0). In contrast, the flame retardant tests of the comparative examples all failed (it should be understood that the initial viscosity of Comparative Example 2 was too high (8600 mPa·s), which led to ineffective potting. Therefore, its flame retardant properties were no longer tested).

[0131] Specifically, in Comparative Examples 1 and 4, when the content of the FR-1 flame retardant is less than 8% by weight based on the total weight of the polyol component, the flame retardancy test of the polyurethane foam fails. In Comparative Examples 3 and 5, when the content of the FR-2 flame retardant is less than 5% by weight based on the total weight of the polyol component, the flame retardancy test of the polyurethane foam fails.

[0132] By comparing Examples 1-9 with Comparative Examples 6-7, when the polyol component does not contain the FR-2 flame retardant but contains inorganic phosphate, the flame retardancy test of the polyurethane foam fails.

[0133] In addition, the mechanical properties, electrical insulation, etc. of the obtained polyurethane foams of Examples 1-9 were also measured. As shown in Table 2, the polyurethane foams of Examples 1-9 exhibit soft high elasticity and good electrical insulation.

[0134] Table 2

[0135]

[0136] The structures, materials, components, compositions, and methods described herein are intended to be representative examples of the present invention, and it should be understood that the scope of the present invention is not limited by the scope of the examples. Those skilled in the art will recognize that the present invention can be practiced with variations of the disclosed structures, materials, compositions, and methods, and such variations are considered to be within the scope of the present invention. Accordingly, the present invention is intended to cover such modifications and variations that fall within the scope of the appended claims and their equivalents.

Claims

1. Polyol component, comprising the following components: (a-1) At least one polyol reactive with isocyanate, (a-2) Chain extender and / or crosslinking agent, (a-3) Foaming agent, (a-4) Optionally, catalyst, (a-5) Solid flame retardant, and (a-6) Optionally, additives and / or auxiliaries, wherein the solid flame retardant comprises FR-1 flame retardant and FR-2 flame retardant, the FR-1 flame retardant is a nitrogen-containing solid flame retardant, a metal-free phosphorus-containing solid flame retardant or a combination thereof, the FR-2 flame retardant is a metal-organic phosphate solid flame retardant, the FR-1 flame retardant accounts for 8 to 20% by weight of the total weight of the polyol component, and the FR-2 flame retardant accounts for 5 to 25% by weight of the total weight of the polyol component.

2. The polyol component according to claim 1, wherein the weight ratio of the FR-2 flame retardant to the FR-1 flame retardant is 3:1 to 1:

4.

3. The polyol component according to claim 1 or 2, wherein The solid flame retardant accounts for 13 to 45% by weight of the total weight of the polyol component.

4. The polyol component according to claim 1 or 2, wherein the nitrogen-containing solid flame retardant comprises at least one selected from the following: melamine, melamine salt, guanidine, melamine cyanurate, melamine polyphosphate, melamine phosphate, melamine formaldehyde, hydroxymethylated melamine, hexamethoxymethyl melamine, urea, dimethylurea, melamine pyrophosphate, dicyandiamide, guanylurea phosphate, glycine, preferably melamine and its derivatives.

5. The polyol component according to claim 1 or 2, wherein the metal-free phosphorus-containing solid flame retardant comprises at least one selected from the following: 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO), triphenyl phosphate, ammonium polyphosphate, red phosphorus, tributyl phosphate (RBP), and mixtures thereof.

6. The polyol component according to claim 1 or 2, wherein the metal-organic phosphate solid flame retardant comprises at least one selected from the following: metal salts of phosphoric acid, phosphonic acid or phosphinic acid, wherein the metal is selected from iron, aluminum, magnesium, zinc, lanthanum or cerium.

7. The polyol component according to claim 1 or 2, wherein the metal-organic phosphate solid flame retardant comprises an organic phosphinic acid metal salt having the following formula: R 1 、R 2 are the same or different and represent a straight-chain or branched C1-C6 alkyl group (more preferably a C1-C4 alkyl group); M represents Al, Mg, Ca, Sb, Sn, Ge, Ti, Fe, Zr, Zn, Ce, Bi, Sr, Mn, Li, Na, K; m represents 1, 2, 3 or 4, Preferably, the organic phosphinic acid metal salt is at least one selected from the following: aluminum diethylphosphinate, aluminum methyl ethylphosphinate, aluminum dipropylphosphinate, aluminum dibutylphosphinate, aluminum ethyl butylphosphinate, aluminum ethylhexylphosphinate, aluminum butylhexylphosphinate, and mixtures thereof.

8. The polyol component according to claim 1 or 2, wherein the polyol reactive with isocyanate is a polyether polyol having a number average molecular weight Mn of 300 to 8000, preferably 3000 to 6500, and 2 ≤ functionality Fn ≤ 3.

9. The polyol component according to claim 1 or 2, wherein the polyol reactive with isocyanate accounts for 35% to 85% by weight, preferably 40% to 70% by weight of the total weight of the polyol component.

10. The polyol component according to claim 8, wherein the polyether polyol further comprises a flame-retardant polyether polyol, and the flame-retardant polyether polyol accounts for 0% to 40% by weight, preferably 5% to 20% by weight of the total weight of the polyether polyol.

11. A potting composition obtained by reacting at least the following components: An isocyanate component, comprising: (b-1) at least one isocyanate, and (b-2) optionally a second flame retardant, and the polyol component according to any one of claims 1-10.

12. The potting composition according to claim 11, wherein the second flame retardant comprises a liquid flame retardant selected from at least one of the following: resorcinol bis(diphenyl) phosphate (RDP), tris(1-chloro-2-propyl) phosphate (TCPP), tricresyl phosphate (TCP).

13. The potting composition according to claim 11 or 12, wherein the second flame retardant accounts for 0% to 40% by weight, preferably 5% to 35% by weight, more preferably 5% to 20% by weight of the total weight of the isocyanate component.

14. The potting composition according to claim 11 or 12, wherein the polyol component and the isocyanate component are mixed at a weight ratio of 100:(30 - 100), preferably 100:(40 - 90).

15. The potting composition according to claim 11 or 12, wherein at a temperature of 25 °C, the initial viscosity measured according to ASTM D2196-15 after mixing the polyol component and the isocyanate component is less than 7000 mPa·s, preferably less than 5000 mPa·s.

16. A polyurethane foam prepared from the potting composition according to any one of claims 11 to 15.

17. The polyurethane foam according to claim 16, wherein the polyurethane foam has a modulus of less than 25 MPa, preferably less than 20 MPa, more preferably less than 10 MPa measured according to ISO1798.

18. The polyurethane foam according to claim 16, wherein the polyurethane foam has a flame retardancy of at least V2 or higher grade, more preferably at least V1 or higher grade, most preferably V0 grade measured according to the UL 94 test.

19. The polyurethane foam according to claim 16, wherein the density of the polyurethane foam is 0.1 - 0.4 g / cm 3 , preferably 0.2 - 0.3 g / cm 3 .

20. A battery product, comprising: a battery cell; and a polyurethane foam located between the battery cells, which is prepared from the potting composition according to any one of claims 11 to 15.

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