A polyurethane composition, a polyurethane microcellular foam and a method of making and use thereof

Abstract

The application provides a polyurethane composition, a polyurethane microcellular foam and a preparation method and application thereof. The polyurethane composition comprises an A component and a B component, the A component comprises 100 parts of a polyhydric alcohol compound, 1-3 parts of a chain extender, 1.003-10 parts of an auxiliary agent and 0.03-5 parts of a catalyst; the B component comprises 14-26 parts of an isocyanate; the polyhydric alcohol compound comprises a polymer polyhydric alcohol, a polyether polyhydric alcohol, a phosphorus-nitrogen-containing polyhydric alcohol and a boron-containing polyhydric alcohol; the mass ratio of the polymer polyhydric alcohol, the polyether polyhydric alcohol, the phosphorus-nitrogen-containing polyhydric alcohol and the boron-containing polyhydric alcohol is (35-45):(35-45):(4-10):(4-10). The polyurethane composition provided by the application avoids releasing toxic and harmful gases during combustion, has good environmental protection performance, has uniform dispersion, high flame retardant performance, strong durability, small amount of flame retardant addition, improves the flame retardant performance and overall stability of the polyurethane foam material.

Description

Technical Field

[0001] This invention relates to the field of polyurethane microporous foam technology, and more particularly to a polyurethane composition, polyurethane microporous foam, its preparation method and application. Background Technology

[0002] Polyurethane (PU), a diverse and high-performance polymer material, is widely used in numerous fields such as energy, automotive, and sporting goods. PU is primarily an organic polymer synthesized from polyols and isocyanates through an addition polymerization reaction. The raw materials for PU are mainly derived from fossil resources, making it highly flammable and rapidly combusting, difficult to extinguish, and releasing toxic and harmful gases during combustion. This poses significant challenges to firefighting and escape, severely limiting the application range of PU.

[0003] To improve the flame retardancy of polyurethane foam, a common method is to incorporate a large amount of inorganic flame retardants during foam preparation to slow down the combustion reaction. These inorganic flame retardants mainly include magnesium hydroxide, aluminum hydroxide, and expandable graphite. However, even with the addition of these large amounts, the flame retardant effect of polyurethane is generally limited. Furthermore, due to the poor compatibility between these inorganic flame retardants and the polymer, and their tendency to migrate and precipitate from the matrix, the mechanical properties of the polyurethane foam material decrease, the cell structure is damaged, and its thermal insulation performance is affected. Moreover, during continuous use of polyurethane products, various inorganic flame retardants in the polymer matrix exhibit instability, uneven dispersion, and migration problems, severely impacting the flame retardant performance and overall stability of the polyurethane foam material. Summary of the Invention

[0004] To address the problems of existing polyurethane foam materials having high additive amounts, poor compatibility, and damaged cell structure when inorganic flame retardants are added, thus affecting the flame retardant and thermal insulation properties of the foam, this invention provides a polyurethane composition, polyurethane microporous foam, its preparation method, and its application.

[0005] In a first aspect, the present invention provides a polyurethane composition comprising component A and component B;

[0006] Component A comprises 100 parts of polyol compound, 1-3 parts of chain extender, 1.003-10 parts of auxiliaries, and 0.03-5 parts of catalyst;

[0007] Component B comprises 14 to 26 parts of isocyanate;

[0008] The polyol compounds include polymeric polyols, polyether polyols, phosphorus-nitrogen-containing polyols, and boron-containing polyols;

[0009] The mass ratio of the polymer polyol, polyether polyol, phosphorus-nitrogen polyol and boron-containing polyol is (35~45):(35~45):(4~10):(4~10).

[0010] Preferably, the hydroxyl value of the polymer polyol is 54.0~58.0 mgKOH / g;

[0011] The hydroxyl value of the polyether polyol is 20.0~70.0 mgKOH / g.

[0012] Preferably, the molar equivalent ratio of the isocyanate group in the isocyanate to the hydroxyl group in the polyol compound is (0.9-1.3):1.

[0013] Preferably, the 1.003-10 parts of additives include 1-5 parts of foaming agent and 0.03-5 parts of foam stabilizer;

[0014] The isocyanate comprises 7-13 parts toluene diisocyanate and 7-13 parts isophorone diisocyanate;

[0015] The catalyst includes at least one of tertiary amine catalysts and organometallic compound catalysts;

[0016] The chain extender includes at least one of alcohol chain extenders and amine chain extenders;

[0017] The foaming agent includes at least one of water, carbon dioxide, and hydrohalogenated olefins;

[0018] The foam stabilizer includes at least one of the following: organopolysiloxane, organopolysiloxane-polyoxyethylene copolymer, polyolefin siloxane with polyoxyethylene side chains, silicone-lubricating grease copolymer and other silicone compounds, anionic surfactants such as sodium dodecylbenzenesulfonate and sodium dodecyl sulfate, polyether siloxane, and phenolic compounds.

[0019] Secondly, this application provides a polyurethane microporous foaming cotton, which is prepared from the polyurethane composition described above.

[0020] Thirdly, this application provides a method for preparing the above-mentioned polyurethane microporous foam, comprising the following steps:

[0021] Component A and component B are stirred evenly at 0~10℃ and 1MPa~10MPa to form a prepolymer;

[0022] The prepolymer is coated onto the surface of a substrate and cured to obtain the polyurethane microporous foam; the curing temperature is 80~130℃.

[0023] Preferably, the preparation method of the phosphorus-nitrogen-containing polyol includes the following steps:

[0024] Under a protective atmosphere, 5-hydroxymethylfurfural, an alkanolamine, and a first organic solvent are mixed evenly and subjected to a first reaction to obtain a first mixed solution.

[0025] The 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and the second organic solvent are mixed evenly and then added to the first mixed solution. After the mixture is evenly mixed, a second reaction is carried out. After the second reaction is completed, a first post-treatment is performed to obtain the phosphorus-nitrogen polyol.

[0026] Preferably, the molar ratio of the alkanolamine, the 5-hydroxymethylfurfural, and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is 1:(0.9~1):(0.8~1).

[0027] The reaction temperature of the first reaction is 75~95℃, and the reaction time of the first reaction is 4~12h;

[0028] The reaction temperature of the second reaction is 75~95℃, and the reaction time is 10~24h;

[0029] Both the first organic solvent and the second organic solvent include alcohol solvents.

[0030] Preferably, the method for preparing the boron-containing polyol includes the following steps:

[0031] Under a protective atmosphere, glycerol is heated to 90-120°C, boric acid is added, and a third reaction is carried out under a vacuum of 0.1-0.5 MPa. After the third reaction is completed, the boron-containing polyol is obtained.

[0032] The temperature of the third reaction is 140~160°C, and the time of the third reaction is 3~6 hours;

[0033] The molar ratio of glycerol to boric acid is (2~2.3):1.

[0034] Fourthly, this application provides an application of the polyurethane microporous foam cotton described above or the polyurethane microporous foam cotton prepared by the preparation method described above in the fields of construction, electronic assembly, and automobiles.

[0035] The polyurethane composition provided in this application has the following effects: 1) The polyether polyols contained therein help to form high-density cells, and without the addition of flame retardants that destroy the cell structure, it can effectively improve the thermal insulation performance of polyurethane microporous foam; the increase in soft chains in the polyol compounds is beneficial to the formation of foam with uniformly distributed cells. 2) The added phosphorus-nitrogen polyols and boron-containing polyols work synergistically to form a phosphorus-nitrogen-boron synergistic flame retardant system, improving the flame retardant performance of polyurethane microporous foam, avoiding the release of toxic and harmful gases during combustion, and having good environmental performance; at the same time, the boron-containing polyols and phosphorus-nitrogen-containing polyols exist stably in the polymer, without destroying the cell structure, and have uniform dispersion, high flame retardant performance, strong durability, low flame retardant addition, no migration, and can also take into account the excellent properties of the polymer matrix itself, improving the flame retardant performance and overall stability of the polyurethane foam material. 3) The urethane formed by the reaction of polyol compounds and isocyanates constitutes the hard chain of the polymer, improving the mechanical properties of polyurethane microporous foam. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0037] To illustrate the technical solution of the present invention, specific embodiments are described below.

[0038] In one embodiment of the present invention, this application provides a polyurethane composition comprising component A and component B;

[0039] Component A comprises 100 parts of polyol compound, 1-3 parts of chain extender, 1.003-10 parts of auxiliaries, and 0.03-5 parts of catalyst;

[0040] Component B comprises 14 to 26 parts of isocyanate;

[0041] The polyol compounds include polymeric polyols, polyether polyols, phosphorus-nitrogen-containing polyols, and boron-containing polyols;

[0042] The mass ratio of the polymer polyol, polyether polyol, phosphorus-nitrogen polyol and boron-containing polyol is (35~45):(35~45):(4~10):(4~10).

[0043] The mass ratio of the polymer polyol, polyether polyol, phosphorus-nitrogen polyol, and boron-containing polyol is (35~45):(35~45):(4~10):(4~10). By adjusting the ratio of polyether polyol and polymer polyol, the content of soft chains is increased, which improves the flexibility of the molecular chains. Furthermore, the increase in soft chains is conducive to the uniform distribution of foam cells, which helps to form high-density foam cells and improves the thermal insulation performance of polyurethane microporous foam cotton material, thereby improving the overall performance of the material. The mass ratio of the polymer polyol, polyether polyol, phosphorus-nitrogen polyol and boron-containing polyol is (35~45):(35~45):(4~10):(4~10). It can also be understood that 100 parts of polyol compound include 35~45 parts of polymer polyol, 35~45 parts of polyether polyol, 4~10 parts of phosphorus-nitrogen polyol and 4~10 parts of boron-containing polyol. The number of parts of polyether polyol in 100 parts of polyol compound can be 35 parts, 37 parts, 39 parts, 40 parts, 41 parts, 42 parts, 43 parts, 45 parts, etc. Similarly, the number of polymeric polyols in 100 parts of polyol compounds can be 35, 37, 39, 40, 41, 42, 43, 45, etc.; the number of phosphorus-nitrogen polyols in 100 parts of polyol compounds can be 4, 5, 6, 7, 8, 9, 10, etc.; and the number of boron-containing polyols in 100 parts of polyol compounds can be 4, 5, 6, 7, 8, 9, 10, etc.

[0044] Polyol compounds and isocyanates react to form urethane esters, which constitute the hard chains of the polymer and improve the mechanical properties of polyurethane microporous foam.

[0045] The addition of phosphorus-nitrogen polyols can improve the tensile strength of polyurethane microporous foam.

[0046] Boron-containing polyols and phosphorus-nitrogen-containing polyols work synergistically. In the flame retardant, element B accelerates the formation of a glassy insulating layer, while element NP promotes the dehydration and char formation of the material. The synergistic effect of boron-containing polyols and phosphorus-nitrogen-containing polyols jointly promotes the densification of the char layer, forming a phosphorus-nitrogen-boron synergistic flame retardant system. This enhances the integrity and continuity of the char layer. All elements exhibit good synergistic heat insulation and flame retardant effects, thereby strengthening the barrier formed in the condensed phase.

[0047] The addition of boron-containing polyols and phosphorus-nitrogen-containing polyols to prepare polyurethane microporous foam increases the limiting oxygen index and achieves a flame retardant rating of V-0, thus significantly improving the flame retardant performance of the polyurethane microporous foam and preventing the release of toxic and harmful gases during combustion, resulting in excellent environmental performance. Compared with the traditional method of directly adding inorganic flame retardants, the polyurethane microporous foam provided in this application, by adding boron-containing polyols and phosphorus-nitrogen-containing polyols to form a phosphorus-nitrogen-boron synergistic flame retardant system, avoids the problems of poor compatibility between inorganic flame retardants and polymers, easy migration and precipitation from the matrix, which would reduce the mechanical properties of the polyurethane foam material and damage the cell structure. The flame-retardant boron-containing polyols and phosphorus-nitrogen-containing polyols are stably present in the polymer, exhibiting uniform dispersion, high flame retardant performance, strong durability, low flame retardant addition, no migration, and can also take into account the excellent properties of the polymer matrix itself, improving the flame retardant performance and overall stability of the polyurethane foam material.

[0048] The polyurethane composition provided in this application has the following effects: 1) The polyether polyol it contains helps to form high-density cells, and without the addition of inorganic flame retardants that destroy the cell structure, it can effectively improve the thermal insulation performance of polyurethane microporous foam; the increase in soft chains in the polyol compounds is beneficial to the formation of foam with uniformly distributed cells. 2) The added phosphorus-nitrogen polyol and boron-containing polyol synergistically constitute a phosphorus-nitrogen-boron synergistic flame retardant system, improving the flame retardant performance of polyurethane microporous foam, avoiding the release of toxic and harmful gases during combustion, and having good environmental performance; at the same time, the boron-containing polyol and the phosphorus-nitrogen-containing polyol exist stably in the polymer, do not destroy the cell structure, and have uniform dispersion, high flame retardant performance, strong durability, low flame retardant addition, no migration, and can also take into account the excellent properties of the polymer matrix itself, improving the flame retardant performance and overall stability of the polyurethane foam material. 3) The urethane formed by the reaction of polyol compounds and isocyanates constitutes the hard chain of the polymer, improving the mechanical properties of polyurethane microporous foam.

[0049] In some embodiments, the 1.003-10 parts of additives include 1-5 parts of foaming agent and 0.03-5 parts of foam stabilizer;

[0050] The foaming agent includes at least one of water, carbon dioxide, and hydrohalogenated olefins;

[0051] The foam stabilizer includes at least one of the following: organopolysiloxane, organopolysiloxane-polyoxyethylene copolymer, polyolefin siloxane with polyoxyethylene side chains, silicone-lubricating grease copolymer and other silicone compounds, anionic surfactants such as sodium dodecylbenzenesulfonate and sodium dodecyl sulfate, polyether siloxane, and phenolic compounds.

[0052] Foaming agents promote foaming, and the amount of foaming agent can be 1 part, 2 parts, 3 parts, 4 parts, 5 parts, etc. Foam stabilizers can be 0.03 parts, 0.1 parts, 1 part, 2 parts, 3 parts, 4 parts, 5 parts, etc. Foam stabilizers promote stable foaming.

[0053] In some embodiments, the isocyanate comprises 7-13 parts toluene diisocyanate and 7-13 parts isophorone diisocyanate. This facilitates the reaction of isocyanate with polyol compounds, resulting in polyurethane microporous foam with uniform pore distribution and a high-density pore structure, thereby improving the thermal insulation, mechanical properties, and flame retardant properties of polyurethane materials.

[0054] In some embodiments, the molar ratio of toluene diisocyanate to isophorone diisocyanate in the isocyanate is (0.8~1.5):1.

[0055] Specifically, controlling the mass ratio of toluene diisocyanate to isophorone diisocyanate to be in the range of (0.8~1.5):1 further facilitates the reaction of isocyanate with polyol compounds, resulting in polyurethane microporous foam with uniform pore distribution and high-density cell structure. The resulting polyurethane material exhibits better thermal insulation, mechanical properties, and flame retardant properties. Specifically, the molar ratio of toluene diisocyanate to isophorone diisocyanate in the isocyanate can be 0.8:1, 0.9:1, 1:1, 1.2:1, 1.3:1, 1.5:1, etc.

[0056] In some embodiments, the catalyst includes at least one of tertiary amine catalysts and organometallic compound catalysts.

[0057] Tertiary amine catalysts include at least one of the following: triethylenediamine, bis(dimethylaminoethyl) ether, N,N-dimethylcyclohexylamine, tetramethylbutanediamine, and dimethylethanolamine;

[0058] Organometallic catalysts include at least one of stannous octoate, dibutyltin dilaurate, and zinc isooctanoate.

[0059] In some embodiments, the chain extender includes at least one of alcohol chain extenders and amine chain extenders.

[0060] Alcohol chain extenders have a molecular weight of 80–450 and a functionality of 2–5.

[0061] Alcohol chain extenders include at least one of 1,4-butanediol, diethylene glycol, ethylene glycol, trimethylolpropane, pentaerythritol, and low molecular weight polyether polyols.

[0062] The functionality of amine chain extenders is 3 to 4.

[0063] Amine chain extenders include at least one of diethyltoluenediamine, triethanolamine, diethanolamine, and ethanolamine.

[0064] In some embodiments, the hydroxyl value of the polymer polyol is 54.0~58.0 mgKOH / g;

[0065] The hydroxyl value of the polyether polyol is 20.0~70.0 mgKOH / g.

[0066] Specifically, by limiting the hydroxyl values ​​of polymer polyols and polyether polyols to the above range, the content of soft chains in polyols is controlled, the proportion of soft chains is increased, the flexibility of molecular chains is improved, and the polyurethane foam is given flexibility and elasticity. At the same time, the increase of soft chains is conducive to the formation of uniform cell distribution, which helps to form high-density cells, improves the thermal insulation performance of the material, and thus improves the overall performance of the material.

[0067] In some embodiments, the polymer polyol has a hydroxyl value of 54.0-58.0 mgKOH / g, a viscosity of 400-650 mPa·s at 25°C, an acid value of ≤0.05 mgKOH / g, a moisture content of ≤0.05%, a pH value of 5.5-7.5, and a color APHA of ≤30.

[0068] In some embodiments, the polyether polyol includes polypropylene glycol with a hydroxyl value of 26-30 mg KOH / g.

[0069] In some embodiments, the molar equivalent ratio of the isocyanate group in the isocyanate to the hydroxyl group in the polyol compound is (0.9 to 1.3):1.

[0070] Specifically, the synthesis of polyurethane mainly depends on the reaction between -NCO in isocyanates and -OH in polyol compounds. Controlling the molar equivalent ratio of -NCO to -OH in the range of (0.9 to 1.3):1 determines the number of urethane bonds, forms an ideal cross-linked network structure, improves the degree of cross-linking of polyurethane, and forms polyurethane materials with uniform pore distribution and high-density foam structure, thereby improving the thermal insulation and mechanical properties of polyurethane.

[0071] In some embodiments, the mass ratio of the phosphorus-nitrogen polyol to the boron-containing polyol in the polyol compound is (0.4~2.5):1.

[0072] Controlling the mass ratio of phosphorus-nitrogen polyol to boron-containing polyol within the above-mentioned range is beneficial to the synergistic effect of phosphorus-nitrogen polyol and boron-containing polyol, thereby improving the flame retardant properties of polyurethane microporous foam.

[0073] In some preferred embodiments, the mass ratio of the phosphorus-nitrogen polyol to the boron-containing polyol is 1:1.

[0074] Secondly, this application provides a polyurethane microporous foaming cotton, which is prepared from the polyurethane composition described above.

[0075] The polyurethane microporous foam provided in this application has the following effects: it has a structure with uniformly distributed and high-density cells, and good flame retardant, thermal insulation and mechanical properties.

[0076] Thirdly, this application provides a method for preparing the above-mentioned polyurethane microporous foam, comprising the following steps:

[0077] Component A and component B are stirred evenly at 0~10℃ and 1MPa~10MPa to form a prepolymer;

[0078] The prepolymer is coated onto the surface of a substrate and cured to obtain the polyurethane microporous foam; the curing temperature is 80~130℃.

[0079] The method for preparing polyurethane microporous foam provided in this application involves first stirring components A and B evenly to form a prepolymer, and then coating the prepolymer onto the surface of a substrate and curing it to obtain polyurethane microporous foam. The preparation method is simple, and the resulting polyurethane microporous foam has good thermal insulation performance, high flame retardancy, and good mechanical properties. At the same time, the polyurethane foam has the characteristics of uniform cell distribution and high cell density.

[0080] The curing temperature can be in the following ranges: 80~90℃, 90~100℃, 100~115℃, 115~125℃ or 125~130℃.

[0081] In some embodiments, the curing time is 5s to 20s.

[0082] In some embodiments, the method for preparing the phosphorus-nitrogen-containing polyol includes the following steps:

[0083] Under a protective atmosphere, 5-hydroxymethylfurfural, an alkanolamine, and a first organic solvent are mixed evenly and subjected to a first reaction to obtain a first mixed solution.

[0084] The 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and the second organic solvent are mixed evenly and then added to the first mixed solution. After the mixture is evenly mixed, a second reaction is carried out. After the second reaction is completed, a first post-treatment is performed to obtain the phosphorus-nitrogen polyol.

[0085] The abbreviation for 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is DOPO.

[0086] Specifically, 5-hydroxymethylfurfural, an alkanolamine, and a first organic solvent are mixed evenly, and then a first reaction is carried out to obtain a first mixed solution. This first reaction can be a first reflux reaction. The reaction principle of 5-hydroxymethylfurfural and the alkanolamine is as follows: the aldehyde group in 5-hydroxymethylfurfural reacts with the amine group in the alkanolamine to generate compound 1, which is the compound shown in Formula 1. Compound 1 then undergoes a second reaction with 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide to generate compound 2, which is the compound shown in Formula 2. It should be noted that the second reaction can be a reflux reaction, and compound 2 is the product, a phosphorus-nitrogen polyol.

[0087] , .

[0088] The equation for the reaction of 5-hydroxymethylfurfural with ethanolamine is as follows:

[0089] ;

[0090] The equation for the reaction of compound 1 with 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is as follows:

[0091] .

[0092] 5-Hydroxymethylfurfural contains a furan ring, an oxygen-containing five-membered heterocyclic structure. Its rigidity and aromaticity are similar to those of the benzene ring, but its polarity is higher. Introducing a furan ring into polyurethane can enhance the rigidity of the molecular chain, improving the tensile strength of polyurethane microporous foam. Furthermore, its combination with the soft segments of polyether polyols promotes polymerization and microphase separation, ultimately resulting in polyurethane microporous foam exhibiting both excellent tensile strength and better compressive strength.

[0093] In some embodiments, the molar ratio of the alkanolamine, the 5-hydroxymethylfurfural, and DOPO is 1:(0.9~1):(0.8~1).

[0094] Specifically, using 5-hydroxymethylfurfural, alkanolamine, and DOPO as reactants, and controlling the molar ratio of alkanolamine, 5-hydroxymethylfurfural, and DOPO to be in the range of 1:(0.9~1):(0.8~1), the resulting phosphorus-nitrogen polyol has strong hydroxyl reactivity.

[0095] In some embodiments, the reaction temperature of the first reaction is 75~95℃, and the reaction time of the first reaction is 4~12h;

[0096] The reaction temperature of the second reaction is 75~95℃, and the reaction time is 10~24h;

[0097] Both the first organic solvent and the second organic solvent include alcohol solvents.

[0098] Specifically, a first reaction temperature of 75-95℃ and a first reaction time of 4-12 hours are conducive to the reaction of 5-hydroxymethylfurfural with an alkanolamine to form compound 1. If the first reaction temperature is below 75-95℃, 5-hydroxymethylfurfural does not react with the alkanolamine; if the first reaction temperature is above 75-95℃, side reactions and byproducts increase.

[0099] The second reaction temperature is 75-95℃, and the reaction time is within the range of 10-24 hours. This facilitates the formation of a phosphorus-nitrogen-containing polyol from compound 1 and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide. If the second reaction temperature is below 75-95℃, compound 1 does not react with 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide. If the second reaction temperature is above 75-95℃, side reactions and byproducts increase.

[0100] The first reaction temperature can be 75℃, 75℃, 80℃, 82℃, 85℃, 86℃, 88℃, 90℃, 92℃, 95℃, etc.; the first reaction time can be 4h, 5h, 6h, 7h, 8h, 9h, 10h, 11h, 12h, etc.

[0101] The temperature of the second reaction can be 75℃, 75℃, 80℃, 82℃, 85℃, 86℃, 88℃, 90℃, 92℃, 95℃, etc.; the time of the second reaction can be 10h, 12h, 13h, 15h, 16h, 20h, 22h, 23h, 24h, etc.

[0102] In some preferred embodiments, the first organic solvent includes ethanol, propanol, butanol, isopropanol, etc. The second organic solvent includes ethanol, propanol, butanol, isopropanol, etc.

[0103] In some preferred embodiments, the alcoholamines include ethanolamine, isopropanolamine, and n-propanolamine.

[0104] In some preferred embodiments, the first organic solvent is anhydrous ethanol.

[0105] In some embodiments, the process of obtaining the phosphorus-nitrogen-containing polyol by performing a first post-processing after the second reaction includes the following steps: obtaining a second mixed solution after the second reaction, filtering the second mixed solution to obtain a solid product, and washing and drying the solid product to obtain the phosphorus-nitrogen-containing polyol.

[0106] Specifically, the second mixed solution is first cooled to 20-40°C, then filtered to obtain a solid product. The solid product is washed at least once with a detergent, and then dried to obtain a phosphorus-nitrogen polyol. The detergent includes an alcohol solvent, preferably ethanol.

[0107] In some embodiments, the method for preparing the boron-containing polyol includes the following steps:

[0108] Under a protective atmosphere, glycerol is heated to 90-120°C, boric acid is added, and a third reaction is carried out under a vacuum of 0.1-0.5 MPa. After the third reaction is completed, the boron-containing polyol is obtained.

[0109] Specifically, in the preparation of boron-containing polyols, boric acid and glycerol are used as reactants. The resulting boron-containing polyols can synergistically work with phosphorus-nitrogen polyols. The boron element accelerates the formation of a glassy insulating layer, while the nitrogen and phosphorus elements promote the dehydration and char formation of the material. The furan ring and boron compounds jointly promote the densification of the char layer. All elements exhibit good synergistic heat insulation and flame retardant effects, forming a phosphorus-nitrogen-boron synergistic flame retardant system. This enhances the integrity and continuity of the char layer, thereby strengthening the barrier formed in the condensed phase and improving the flame retardancy of polyurethane microporous foam.

[0110] In the process of preparing polyurethane microporous foam, adding only phosphorus-containing polyols without adding phosphorus-nitrogen polyols can result in a limiting oxygen index (LOI) of 20-30%. The polyurethane microporous foam provided in this application, which adds both phosphorus-containing polyols and phosphorus-nitrogen polyols, has an LOI ≥ 30%, a UL-94 V-0 rating, and a significantly reduced heat release rate.

[0111] In some embodiments, the temperature of the third reaction is 140~160°C, and the time of the third reaction is 3~6h;

[0112] The molar ratio of glycerol to boric acid is (2~2.3):1.

[0113] Specifically, the third reaction temperature, within the range of 140-160°C, and the third reaction time, within the range of 3-6 hours, facilitates the reaction of boric acid and glycerol to produce boron-containing polyols. If the reaction temperature is below 140°C, the reaction is incomplete and the reaction rate is slow; if the reaction temperature is above 160°C, side reactions and byproducts increase. The fourth reaction temperature can be 140°C, 142°C, 145°C, 147°C, 149°C, 150°C, 155°C, 158°C, 160°C, etc.

[0114] The molar ratio of glycerol to boric acid is (2~2.3):1. Using 1 mol of boric acid is beneficial for the complete reaction of boric acid and at the same time reduces costs.

[0115] Glycerol and boric acid undergo a third reaction to yield a colorless, transparent, viscous product, which is a boron-containing polyol.

[0116] The reaction equation for glycerol and boric acid is as follows:

[0117] .

[0118] In some embodiments, a protective atmosphere refers to an atmosphere of protective gases, including nitrogen and rare gases.

[0119] In some preferred embodiments, the protective gas is nitrogen.

[0120] Fourthly, this application provides an application of the polyurethane microporous foam cotton described above or the polyurethane microporous foam cotton prepared by the preparation method described above in the fields of construction, electronic assembly, and automobiles.

[0121] The polyurethane microporous foam provided in this application, or the polyurethane microporous foam prepared by the method thereof, has high resilience, good mechanical properties, high flame retardancy, and good thermal insulation. It can be used in the construction industry, such as as a thermal insulation material; in the electronic assembly industry, such as as a sealing material, cushioning material, sound-absorbing material, and thermal insulation material; and in the automotive industry, as a cushioning material and thermal insulation material.

[0122] The present invention will be further illustrated by the following examples.

[0123] Example 1

[0124] S1: Preparation of phosphorus-nitrogen-containing polyols, the preparation steps are as follows:

[0125] In a four-necked flask, 206 g of 5-hydroxymethylfurfural (molecular weight 126.11 g / mol, calculated as 1.63 mol) and 100 g of ethanolamine (molecular weight 61.08 g / mol, calculated as 1.63 mol) were dissolved in anhydrous ethanol (200 mL), and nitrogen gas was added. Under a nitrogen atmosphere, the mixture was stirred and heated to 80°C for a first reflux reaction for 6 h. Subsequently, a mixed solution 1 consisting of anhydrous ethanol and DOPO (353 g of DOPO, molecular weight 216.17 g / mol, calculated as 1.63 mol) (300 mL) was added, and a second reflux reaction was continued at 80°C for 12 h. After the second reflux reaction, a first mixed solution was obtained. The first mixed solution was cooled to room temperature and filtered to obtain the filtrate. The filtrate was dried to obtain the phosphorus-nitrogen polyol.

[0126] The aforementioned DOPO is 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, purchased from Shanghai Aladdin Biochemical Technology Co., Ltd. The molar ratio of ethanolamine, 5-hydroxymethylfurfural, and DOPO is 1:1:1.

[0127] S2: Preparation of boron-containing polyols, the preparation steps are as follows:

[0128] In a four-necked flask, 100 g of glycerol (molecular weight 92.094 g / mol, calculated as 1.09 mol) was added, and nitrogen gas was used to replace the nitrogen atmosphere. Under nitrogen atmosphere, the mixture was stirred and heated to 110°C. Then, 33.50 g of boric acid (molecular weight 61.83 g / mol, calculated as 0.54 mol) was added dropwise. The vacuum was adjusted to 0.1 MPa, and the mixture was stirred and heated to 150°C for the third reaction. The third reaction took 3 hours, yielding a colorless, transparent, viscous liquid product containing boron polyol. The molar ratio of glycerol to boric acid was 2:1.

[0129] S3: Obtain component A

[0130] Component A: 100 parts polyol compound, 2.5 parts foaming agent, 3 parts chain extender, 1 part catalyst, and 3 parts foam stabilizer.

[0131] The 100 parts of polyol compounds consist of 40 parts polymer polyol, 40 parts polyether polyol, 10 parts phosphorus-nitrogen polyol, and 10 parts boron-containing polyol.

[0132] The polymeric polyol was purchased from Chengdu Xilantia Technology Co., Ltd. of Wanhua Chemical, with the brand name LEP-5631D and a hydroxyl value of 55.5 mgKOH / g; the polyether polyol was purchased from Nantong Yixun Chemical Co., Ltd., with the product being polypropylene glycol PPG-4000 and a hydroxyl value of 28 mgKOH / g; the phosphorus-nitrogen-containing polyol was selected from the preparation in step S1 above. The boron-containing polyol was selected from the preparation in step S2 above.

[0133] The foaming agent is water.

[0134] The chain extender was purchased from Xinjiang Guotai Xinhua Chemical Co., Ltd., under the brand name BDO, and the product was 1,4-butanediol.

[0135] The catalyst consists of 0.5 parts stannous octoate and 0.5 parts aliphatic tertiary amine. The stannous octoate was purchased from Nanjing Chemical Reagent Co., Ltd., and the aliphatic tertiary amine was purchased from Evonik Japan Co., Ltd., with the brand name DABCO33LSI.

[0136] The foam stabilizer was purchased from Dow Corning, under the brand name SZ-1136, and is a product containing organic silicone.

[0137] S4: Obtain component B

[0138] Component B: 10.5 parts toluene diisocyanate (TDI) and 10.5 parts isophorone diisocyanate (IPDI).

[0139] Toluene diisocyanate was purchased from Wanhua Chemical Company under the brand name WANNATE® TDI-80; isophorone diisocyanate was purchased from Guangdong Haoyi Chemical Technology Co., Ltd. (industrial grade).

[0140] S5: Preparation of polyurethane microporous foam cotton, the steps are as follows:

[0141] S51: Place component A obtained in step S3 and component B obtained in step S4 into a container and stir at 0℃~10℃ and 1MPa~10MPa for 5 minutes to 15 minutes until homogeneous to form a prepolymer.

[0142] S52: The prepolymer obtained in step S51 is transported to a coating machine via a pipeline, and the prepolymer is coated onto the substrate by the coating machine. During the process of transporting the prepolymer to the coating machine via the pipeline, the prepolymer is simultaneously preheated. The substrate coated with the prepolymer is placed in a curing oven for curing and molding to form polyurethane microporous foam. The substrate is PET.

[0143] When the substrate coated with the prepolymer is placed in a curing oven for curing, the curing temperature is 80℃~130℃ and the curing time is 5 seconds~20 seconds.

[0144] Examples 2-16 and Comparative Examples 1-3

[0145] Examples 2-16 and Comparative Examples 1-3 are largely the same as Example 1, except that the contents of polymeric polyols, polyether polyols, phosphorus-nitrogen-containing polyols, and boron-containing polyols in component A are different; and the contents of TDI and IPDI in component B are different, as detailed in Table 1. The molar equivalent ratio of isocyanate groups to hydroxyl groups in Example 10 is 1:1.3, in Example 11 it is 1:0.9, and in Example 12 it is 1:0.8.

[0146] Example 17

[0147] Most of the steps in Example 17 are the same as those in Example 1, except for step S1. In Example 17, the first reflux reaction temperature is 100°C and the second reflux reaction temperature is 100°C when preparing the phosphorus-nitrogen polyol. The rest are the same as in Example 1.

[0148] Example 18

[0149] Most of the steps in Example 18 are the same as those in Example 1, except for step S1. In Example 18, when preparing phosphorus-nitrogen polyol, the first reflux reaction temperature is 95°C and the second reflux reaction temperature is 95°C. The rest are the same as in Example 1.

[0150] Example 19

[0151] Most of the steps in Example 19 are the same as those in Example 1, except for step S1. In Example 19, the first reflux reaction temperature is 75°C and the second reflux reaction temperature is 75°C when preparing the phosphorus-nitrogen polyol. The rest is the same as in Example 1.

[0152] Example 20

[0153] Most of the steps in Example 20 are the same as those in Example 1, except for step S1. In Example 20, when preparing the phosphorus-nitrogen polyol, the mass of 5-hydroxymethylfurfural added is 186g, the mass of DOPO in mixed solution 1 is 284g, and the molar ratio of ethanolamine, 5-hydroxymethylfurfural and DOPO is 1:0.9:0.8.

[0154] Example 21

[0155] Most of the steps in Example 21 are the same as those in Example 1, except that the temperature of the third reaction in the preparation of boron-containing polyol is 170°C. The rest are the same as in Example 1.

[0156] Comparative Examples 4 to 5

[0157] Comparative Examples 4 and 5 are largely the same as Example 1, except that the contents of polymer polyol, polyether polyol, phosphorus-nitrogen polyol and boron-containing polyol in Component A of Table 1 are different; and the contents of TDI and IPDI in Component B are different. Component A of Comparative Examples 4 and 5 also includes DOPO. The amount of DOPO in Comparative Example 4 is 40 parts and the amount of DOPO in Comparative Example 5 is 20 parts. The rest is the same as in Example 1.

[0158] Table 1

[0159]

[0160] Performance testing

[0161] The polyurethane microporous foam prepared in the above embodiments and comparative examples were used as samples for the following tests.

[0162] 1) Resilience:

[0163] The springback rate of the samples was measured at room temperature using a universal tensile testing machine. According to ASTM D-412 specifications, the tensile speed was 50 mm / min, and the samples were subjected to five cyclic tensile tests. The deformation recovery rate R (%) was calculated using the following formula:

[0164] R=

[0165] In the formula, R represents the deformation recovery rate, L0 represents the original length of the polyurethane microporous foam, L1 represents the length after elongation with external force, and L2 represents the length after removal of external force. Fill the result of R into Table 2; the value of R is the resilience rate.

[0166] 2) Tensile strength

[0167] According to the GB / T6344-2008 test standard, polyurethane microporous foam is cut into dumbbell-shaped specimens using a slicer (take the "1" type dumbbell specimen in the standard). The distance between the upper and lower clamps is 62.5 mm. The specimen is placed between the upper and lower clamps of the tensile testing machine, and the tensile rate is adjusted to 500 mm / min. The number of specimens should meet the requirement that at least 5 break within the gauge length, and at least 5 specimens are required.

[0168] 3) Elongation at break

[0169] According to the GB / T6344-2008 test standard, polyurethane microporous foam is cut into dumbbell-shaped specimens using a slicer (take the "1" type dumbbell specimen in the standard). The distance between the upper and lower clamps is 62.5 mm. The specimen is placed between the upper and lower clamps of the tensile testing machine, and the tensile rate is adjusted to 500 mm / min. The number of specimens should meet the requirement that at least 5 break within the gauge length, and at least 5 specimens are required.

[0170] 4) Permanent compression deformation

[0171] According to the ASTM D3574 test standard, polyurethane microporous foam is cut into 50×50mm pieces and stacked to a thickness of about 10mm (multiple samples are allowed to be stacked for testing). The thickness is compressed by 70% using a compression tool. The sample is then placed at room temperature (25~30℃) for 24 hours. After the test is completed, the sample needs to be allowed to recover for 30 minutes before the sample thickness is tested again, and the residual deformation value is calculated.

[0172] 5) Limiting Oxygen Index (LOI) Test

[0173] According to standard ASTM D2863-97, the synthesized polyurethane samples were tested using a limiting oxygen index tester. The sample size was 100mm × 10mm × 4mm. All samples were tested at least five times and the average value was taken.

[0174] 6) UL-94 Vertical Burning Test (UL-94)

[0175] According to standard ASTM D3801-2010, the corresponding test was carried out on a vertical combustion testing machine, and the sample size was 130mm × 13mm × 3mm.

[0176] 7) Thermal conductivity

[0177] According to standard GB / T10295-2008, the sample size for thermal conductivity testing is 200mm×200mm×25mm, the temperature of the upper plate of the instrument is 2℃, the temperature of the lower plate is 18℃, the average temperature is 10℃, and the temperature difference is 16℃.

[0178] The test results are shown in Table 2.

[0179] Table 2

[0180]

[0181] As shown in Table 1, compared with Comparative Examples 6-7, Examples 1-3 contain less polymer polyol or polyether polyol in the polyol compounds, resulting in polyurethane with low tensile strength, high permanent compression set, low resilience, high thermal conductivity, and poor insulation effect. This indicates that a mass ratio of polymer polyol, polyether polyol, phosphorus-nitrogen polyol, and boron-containing polyol in the polyol compounds within the range of (35~45):(35~45):(4~10):(4~10) is beneficial for forming polyurethane microporous foam with uniformly distributed and high-density cell structure, resulting in good mechanical properties and insulation effect.

[0182] Comparing Example 1 with Comparative Examples 1, 2, and 3, Comparative Example 3, without the addition of phosphorus-nitrogen-containing polyols and boron-containing polyols, resulted in a polyurethane microporous foam with an extremely low limiting oxygen index and poor flame retardant properties. Comparative Example 1, with the addition of phosphorus-nitrogen-containing polyols, yielded a polyurethane microporous foam with good mechanical and thermal insulation properties, but a low limiting oxygen index and a UL-94 flammability rating of V-1. Comparative Example 2, with the addition of boron-containing polyols, resulted in a polyurethane microporous foam with low tensile strength, a low limiting oxygen index, and a UL-94 flammability rating of V-1. This demonstrates that simultaneously adding phosphorus-nitrogen-containing polyols and boron-containing polyols to polyol compounds can significantly improve the performance of the foam. The mass ratio of the polymer polyol, polyether polyol, phosphorus-nitrogen polyol and boron-containing polyol is (35~45):(35~45):(4~10):(4~10). The phosphorus-nitrogen polyol and boron-containing polyol have a synergistic effect, forming a phosphorus-nitrogen-boron synergistic flame retardant system, which improves the flame retardant performance of polyurethane microporous foam. At the same time, the boron-containing polyol and the phosphorus-nitrogen polyol exist stably in the polymer without destroying the cell structure. They have uniform dispersion, high flame retardant performance, strong durability, low flame retardant addition, and do not migrate. They can also take into account the excellent properties of the polymer matrix itself and improve the mechanical properties of polyurethane microporous foam.

[0183] Compared with Comparative Examples 4 and 5, Comparative Examples 4 and 5 did not contain phosphorus-nitrogen polyols or boron-containing polyols, but DOPO was added. The resulting polyurethanes had low mechanical properties, low limiting oxygen index, high flame retardancy rating, and poor thermal insulation performance.

[0184] Comparing Examples 6-8 with Comparative Examples 9 and 8, the addition of excessive phosphorus-nitrogen polyols and boron-containing polyols to the polyol compounds resulted in a higher molar content of hydroxyl groups. To maintain the molar equivalent ratio of -NCO to -OH at 1.1, a higher proportion of isocyanate was added, leading to lower elongation at break, higher compression set, and lower resilience in the resulting polyurethane. This indicates that excessive addition of phosphorus-nitrogen and boron-containing polyols increases the mechanical properties of the polyurethane microporous foam, making it more prone to breakage. In Comparative Example 9, the addition of insufficient phosphorus-nitrogen and boron-containing polyols resulted in a lower limiting oxygen index and lower flame retardant rating in the polyurethane microporous foam. This indicates that by simultaneously adding phosphorus-nitrogen-containing polyols and boron-containing polyols to polyol compounds, with the mass ratio of the polymer polyol, polyether polyol, phosphorus-nitrogen-containing polyol, and boron-containing polyol being (35~45):(35~45):(4~10):(4~10), the resulting polyurethane microporous foam has good flame retardant properties.

[0185] Comparing Examples 9-10 with Examples 11 and Comparative Example 10, the molar ratio of isocyanate groups to hydroxyl groups in Example 11 was less than (0.9~1.3):1, resulting in low tensile strength and low resilience. In Comparative Example 10, the molar ratio of isocyanate groups to hydroxyl groups was greater than (0.9~1.3):1, and the amount of isocyanate in the polyurethane was greater than 14~26 parts. This resulted in polyurethane with low tensile strength, high permanent compression set, low elongation at break, low resilience, and high thermal conductivity. This indicates that a molar ratio of isocyanate groups to hydroxyl groups within the range of (0.9~1.3):1 helps to obtain polyurethane microporous foam with high tensile strength, low permanent compression set, high resilience, high elongation at break, and good thermal insulation performance.

[0186] Comparing Examples 12-13, 16 and Examples 14-15, in Examples 14-15, even if the molar equivalent ratio of isocyanate groups to hydroxyl groups was in the range of (0.9~1.3):1, the toluene diisocyanate was not in the range of 7~13 parts, resulting in poor overall mechanical properties of the polyurethane microporous foam.

[0187] Comparing Examples 1, 18, 19 and Example 17, in the preparation of phosphorus-nitrogen polyols, the temperatures of the first and second reactions were both above 75-95°C. Excessive reaction temperatures resulted in numerous side reactions, high impurity content, flame-retardant pathway defects, and lattice defects. Consequently, the resulting polyurethane microporous foam had a low limiting oxygen index and poor flame-retardant properties. This indicates that when the temperatures of the first and second reactions are within the range of 75-95°C, there are fewer side reactions and fewer impurities in the generated phosphorus-nitrogen polyols. Synergistically, these phosphorus-nitrogen polyols, together with boron-containing polyols, can effectively improve the flame-retardant properties of polyurethane microporous foam.

[0188] Comparing Examples 1 and 21, in the preparation of boron-containing polyols, the temperature of the third reaction was higher than 140-160℃. Excessive reaction temperature led to more side reactions, higher impurity content, flame-retardant pathway defects, and lattice defects. Consequently, the resulting polyurethane microporous foam had a low limiting oxygen index and poor flame-retardant performance. This indicates that when the temperature of the third reaction is within the range of 140-160℃, the generated boron-containing polyol has fewer impurities and, synergistically with phosphorus-nitrogen-containing polyols, can effectively improve the flame-retardant performance of the polyurethane microporous foam.

[0189] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A polyurethane composition, characterized in that, Includes component A and component B; Component A comprises 100 parts of polyol compound, 1-3 parts of chain extender, 1.003-10 parts of auxiliaries, and 0.03-5 parts of catalyst; Component B comprises 14 to 26 parts of isocyanate; The polyol compounds include polymeric polyols, polyether polyols, phosphorus-nitrogen-containing polyols, and boron-containing polyols; The mass ratio of the polymer polyol, polyether polyol, phosphorus-nitrogen-containing polyol and boron-containing polyol is (35~45):(35~45):(4~10):(4~10). The molar equivalent ratio of the isocyanate group in the isocyanate to the hydroxyl group in the polyol compound is (0.9–1.3):1; The isocyanate comprises 7-13 parts toluene diisocyanate and 7-13 parts isophorone diisocyanate; The preparation method of the phosphorus-nitrogen-containing polyol includes the following steps: Under a protective atmosphere, 5-hydroxymethylfurfural, an alkanolamine, and a first organic solvent are mixed evenly and subjected to a first reaction to obtain a first mixed solution. 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and the second organic solvent are mixed evenly and then added to the first mixed solution. The mixture is mixed evenly and a second reaction is carried out. After the second reaction is completed, a first post-treatment is performed to obtain the phosphorus-nitrogen-containing polyol. The reaction temperature of the first reaction is 75~95℃, and the reaction time of the first reaction is 4~12h; The reaction temperature of the second reaction is 75~95℃, and the reaction time is 10~24h; The preparation method of the boron-containing polyol includes the following steps: Under a protective atmosphere, glycerol is heated to 90-120°C, boric acid is added, and a third reaction is carried out under a vacuum of 0.1-0.5 MPa. After the third reaction is completed, the boron-containing polyol is obtained. The temperature of the third reaction is 140~160℃, and the reaction time is 3~6h.

2. The polyurethane composition according to claim 1, characterized in that, The hydroxyl value of the polymer polyol is 54.0~58.0 mgKOH / g; The hydroxyl value of the polyether polyol is 20.0~70.0 mgKOH / g.

3. The polyurethane composition according to claim 1, characterized in that, The additives include 1-5 parts of foaming agent and 0.03-5 parts of foam stabilizer; The isocyanate comprises 7-13 parts toluene diisocyanate and 7-13 parts isophorone diisocyanate; The catalyst includes at least one of tertiary amine catalysts and organometallic compound catalysts; The chain extender includes at least one of alcohol chain extenders and amine chain extenders; The foaming agent includes at least one of water, carbon dioxide, and hydrohalogenated olefins.

4. A polyurethane microporous foam, characterized in that, It is prepared from the polyurethane composition according to any one of claims 1-3.

5. The method for preparing polyurethane microporous foam cotton as described in claim 4, characterized in that, Includes the following steps: Component A and component B are stirred evenly at 0~10℃ and 1MPa~10MPa to form a prepolymer; The prepolymer is coated onto the surface of a substrate and cured to obtain the polyurethane microporous foam; the curing temperature is 80~130℃.

6. The method for preparing polyurethane microporous foam according to claim 5, characterized in that, The molar ratio of the alkanolamine, the 5-hydroxymethylfurfural, and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is 1:(0.9~1):(0.8~1). Both the first organic solvent and the second organic solvent include alcohol solvents.

7. The method for preparing polyurethane microporous foam according to claim 5, characterized in that, The molar ratio of glycerol to boric acid is (2~2.3):

1.

8. Applications of polyurethane microporous foam cotton according to claim 4 or polyurethane microporous foam cotton prepared by any one of claims 5-7 in the fields of construction, electronic assembly, and automobiles.

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