Polyurethane foam composition, polyurethane foam as well as preparation method and application of polyurethane foam

Abstract

The invention discloses a polyurethane foam composition, polyurethane foam and a preparation method and application thereof. The composition provided by the invention contains a polyol composition and an isocyanate composition which are stored in a mixed manner or independently, wherein the polyol composition comprises the following raw materials: polyester polyol, polyether polyol, a basic catalyst, an emulsifier, an organosilicon compound, a foaming agent and water. In the polyurethane foam composition provided by the invention, the nucleating agent in the form of nanoscale silicon dioxide gel is formed through the organic silicon compound, and after dispersion, the nucleating agent has no adverse effect on the viscosity of the system and has no influence on the foam molding processing performance; the problem of precipitation / precipitation layering does not exist in the storage / transportation process, the heat conductivity coefficient of a polyurethane foam system can be reduced, and the heat preservation performance of the polyurethane foam is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of foaming materials, and in particular to a polyurethane foam composition, a polyurethane foam, and a preparation method and application thereof. Background Art

[0002] Polyurethane foam is a polymer formed by mixing and foaming isocyanate and polyether as the main raw materials under the action of various auxiliaries such as foaming agents, catalysts, and nucleating agents through special equipment. Polyurethane foam is commonly used for making the insulation layer of refrigerators.

[0003] In the related art, the nucleation method of polyurethane foam is generally to add perfluorinated compounds or inorganic powder materials. Fluorine-based nucleating agents are expensive and have poor compatibility with the system, and there are precipitation problems during use / storage and transportation; while directly adding inorganic nucleating agents, the inorganic nucleating agents have a large density and are difficult to disperse, and are prone to sedimentation and gelation phenomena. Moreover, the inorganic nucleating agents are hard and have a large particle size, resulting in high wear on the equipment, and often leading to poor insulation performance of the prepared polyurethane foam.

[0004] Therefore, there is an urgent need to research and develop a new polyurethane foam composition to solve the problems of precipitation and separation during the storage and transportation of nucleating agents and the poor insulation performance. Summary of the Invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, in the first aspect of the present invention, a polyurethane foam composition is provided, and the polyurethane foaming nucleating agent can avoid the problems of precipitation and separation during the storage and transportation of the nucleating agent and the poor insulation performance when it is used to prepare polyurethane foam again.

[0006] In the second aspect of the present invention, a preparation method of a polyurethane foam is further provided.

[0007] In the third aspect of the present invention, a polyurethane foam is further provided.

[0008] In the fourth aspect of the present invention, an application of a polyurethane foam is further provided.

[0009] According to an embodiment of the first aspect of the present invention, a polyurethane foam composition is provided, and the composition contains a polyol composition and an isocyanate composition that are stored mixed or independently. The polyol composition includes the following raw materials:

[0010] Polyester polyol, polyether polyol, basic catalyst, emulsifier, silicone compound, blowing agent and water; calculated based on the total content of polyester polyol and polyether polyol being 100 parts by weight, the content of the basic catalyst is 0.3 parts by weight to 5.0 parts by weight, the content of the silicone compound is 0.5 parts by weight to 12 parts by weight, the content of the emulsifier is 0.5 parts by weight to 5 parts by weight; the content of the blowing agent is 13 parts by weight to 50 parts by weight; the content of the water is 2 parts by weight to 6 parts by weight;

[0011] The isocyanate composition includes isocyanate; the dosage of the isocyanate composition is 100 parts by weight to 150 parts by weight.

[0012] The polyurethane foam composition according to the embodiments of the present invention has at least the following beneficial effects:

[0013] The polyurethane foam composition provided by the present invention, through the action of components such as polyester polyol, polyether polyol, basic catalyst, emulsifier, silicone compound, blowing agent and water, has a low thermal conductivity, has no adverse effect on the system viscosity, does not affect the subsequent processing process, and there is no problem of precipitation / separation and delamination during storage / transportation; and the polyurethane foam prepared by using the composition of the present invention has high heat insulation performance.

[0014] According to some embodiments of the present invention, the basic catalyst includes at least one of organic amine catalysts and basic metal catalysts.

[0015] According to some embodiments of the present invention, the organic amine catalysts include at least one of pentamethyldiethylenetriamine, N,N-dimethylcyclohexylamine, methyldiethanolamine, trimethylethylenediamine, triethylenetetramine, diethylenetriamine, diethylenediamine, ethylenediamine or triethylenepentamine.

[0016] According to some embodiments of the present invention, the basic metal catalysts include at least one of organotin catalysts, organoantimony catalysts, organocobalt catalysts, organozirconium catalysts or organobismuth catalysts.

[0017] According to some embodiments of the present invention, the blowing agent includes at least one of physical blowing agents and chemical blowing agents. The blowing agents of the present invention are selected from one or more of the following: water, various hydrocarbons, various hydrofluorocarbons, various hydrofluoroolefins, formic acid, inert gases, various chemical blowing agents that generate nitrogen or carbon dioxide under the foaming reaction conditions, etc.; and mixtures thereof.

[0018] According to some embodiments of the present invention, the chemical blowing agent (such as water) can be used alone or in combination with other chemical and physical blowing agents. Also suitable as chemical blowing agents are organic carboxylic acids such as formic acid, acetic acid, oxalic acid and carboxyl-containing compounds.

[0019] According to some embodiments of the present invention, the physical blowing agent can be used as low-boiling hydrocarbons such as heptane, hexane, n-pentane and isopentane, n-pentane and isopentane, and industrial-grade mixtures of n-butane and isobutane with propane; cycloalkanes such as cyclopentane, cyclohexane; low-boiling ethers such as furan, dimethyl ether and diethyl ether; low-boiling ketones such as acetone and methyl ethyl ketone; alkyl carboxylates such as methyl formate, dimethyl oxalate and vinyl lactate; various hydrochlorofluorocarbons (HCFCs), hydrofluorocarbons (HFCs) and hydrofluoroolefins (HFOs), such as 1,1-dichloro-2,2,2-trifluoroethane, 2,2-dichloro-2-fluoroethane, pentafluoropropane, heptafluoropropane, hexafluorobutene, (E,Z)1,1,1,4,4,4-hexafluoro-2-butene and trans-1-chloro-,3,3,3-trifluoropropene, trans-1,3,3,3-tetrafluoroprop-1-ene, 1,3,3,3-tetrafluoropropene, etc.

[0020] According to some embodiments of the present invention, the emulsifier includes a polysiloxane emulsifier or a non-polysiloxane emulsifier. Thus, the role of the emulsifier is to dissolve the blowing agent and stabilize the cell structure.

[0021] According to some embodiments of the present invention, the emulsifier includes at least one of silicone oil, sorbitan fatty acid ester, and polyoxyethylene sorbitan fatty acid ester.

[0022] According to some embodiments of the present invention, the polyester polyol is generally formed by the condensation (or transesterification) of an organic dicarboxylic acid (anhydride or ester) with a polyol (including a diol) or by the polymerization of a lactone with a polyol. The polyols used to prepare the polyester polyol are generally diols or triols and include ethylene glycol, diethylene glycol, polyethylene glycol such as PEG 200, propylene glycol, dipropylene glycol, polypropylene glycol, butylene glycol, pentylene glycol or hexylene glycol, polyether polyol, glycerol, etc. The polyfunctional carboxylic acids are selected from the following: succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, decane dicarboxylic acid, maleic acid, fumaric acid and phthalic acid, isophthalic acid, terephthalic acid, isonaphthalenedicarboxylic acid, and combinations thereof.

[0023] According to some embodiments of the present invention, the hydroxyl value of the polyester polyol is 300 to 500 mgKOH / g. All individual values and sub-ranges from 300 to 500 are included; for example, the hydroxyl value of the polyester polyol is 300 mgKOH / g, 310 mgKOH / g, 320 mgKOH / g, 330 mgKOH / g, 350 mgKOH / g, 360 mgKOH / g, 380 mgKOH / g, 400 mgKOH / g, 420 mgKOH / g, 440 mgKOH / g, 460 mgKOH / g, 480 mgKOH / g, 500 mgKOH / g or any range value composed of any two of them.

[0024] According to some embodiments of the present invention, the polyether polyol is a hydroxyl-terminated oligomer, and the hydroxyl groups on the main chain are connected by ether bonds. It is formed by ring-opening polymerization of low molecular weight polyols, polyamines or compounds containing active hydrogen as initiators with alkylene oxides under the action of a catalyst. For example, the alkylene oxides are mainly propylene oxide (epoxy propane) and ethylene oxide (epoxy ethane). For example, the polyol initiators include diols such as propylene glycol and ethylene glycol, triols such as glycerol trimethylolpropane, and pentaerythritol, xylitol, sorbitol, sucrose, etc.; for example, the amine initiators are diethylamine, diethylenetriamine, etc.

[0025] According to some embodiments of the present invention, the hydroxyl value of the polyether polyol is 300 to 500 mgKOH / g. It includes all individual values and sub-ranges from 300 to 500; for example, the hydroxyl value of the polyester polyol is 300 mgKOH / g, 310 mgKOH / g, 320 mgKOH / g, 330 mgKOH / g, 350 mgKOH / g, 360 mgKOH / g, 380 mgKOH / g, 400 mgKOH / g, 420 mgKOH / g, 440 mgKOH / g, 460 mgKOH / g, 480 mgKOH / g, 500 mgKOH / g or the range value composed of any two of them.

[0026] According to some embodiments of the present invention, calculated based on the total weight of the polyether polyol and the polyester polyol being 100 parts, the content of the polyester polyol is 0.5 to 30 parts by weight, and the remainder is the polyether polyol.

[0027] Furthermore, the content of the polyester polyol includes any value, all ranges and any sub-ranges therein. For example, it includes 0.5 part by weight, 5 parts by weight, 10 parts by weight, 20 parts by weight, 30 parts by weight, or the sub-range composed of any two of them. Thus, when the content of the polyester polyol is within the above range, the prepared polyurethane foam has good thermal conductivity and high production efficiency.

[0028] According to some embodiments of the present invention, the dosage of the isocyanate composition is 100 parts by weight to 150 parts by weight. It includes any value, all ranges and any sub-ranges therein. For example, it includes but is not limited to 100 parts by weight, 110 parts by weight, 120 parts by weight, 130 parts by weight, 140 parts by weight and 150 parts by weight.

[0029] According to some embodiments of the present invention, the isocyanate includes aliphatic polyisocyanate, cycloaliphatic polyisocyanate, araliphatic polyisocyanate, aromatic polyisocyanate, or a combination thereof. Examples of the isocyanate used in the present invention include, but are not limited to, polymethylene polyphenyl isocyanate; toluene-2,4- / 2,6-diisocyanate; methylene diphenyl diisocyanate; polymeric MDI; triisocyanatononane; naphthyl diisocyanate; 4,4'-diisocyanatodicyclohexyl-methane; 3-isocyanatomethyl-3,3,5-trimethylcyclohexyl isocyanate (isophorone diisocyanate); tetramethylene diisocyanate; hexamethylene diisocyanate; 2-methyl-pentamethylene diisocyanate; 2,2,4-trimethylhexamethylene diisocyanate; dodecamethylene diisocyanate; 1,4-diisocyanatocyclohexane; 4,4'-diisocyanato-3,3'-dimethyl-dicyclohexylmethane; 4,4'-diisocyanato-2,2-dicyclohexylpropane; 3-isocyanatomethyl-1-methyl-1-isocyanatocyclohexane; 1,3-diisocyanato-2-methylcyclohexane; and combinations thereof, etc.

[0030] A method for preparing a polyurethane foam according to an embodiment of the second aspect of the present invention, the method comprising: mixing the components in any one of the above-mentioned compositions:

[0031] Wherein, the operation of mixing the components in the composition includes the following steps:

[0032] S1. Mix polyester polyol, polyether polyol, a part of basic catalyst, emulsifier, water and silicone compound to carry out a hydrolysis reaction; obtain intermediate I;

[0033] S2. Add the remaining basic catalyst, foaming agent and isocyanate composition to the intermediate I for foaming to obtain the polyurethane foam.

[0034] The method for preparing a polyurethane foam according to an embodiment of the present invention has at least the following beneficial effects:

[0035] In the present invention, the silicone compound is subjected to a hydrolysis reaction under the action of polyester polyol, polyether polyol, a part of catalyst and water, and then the remaining basic catalyst, foaming agent and isocyanate composition are added for foaming to obtain the polyurethane foam. The thermal conductivity of the polyurethane foam is reduced, and the heat insulation performance of the polyurethane foam is improved. This is because the nano-sized gel nucleating agent prepared by the in-situ polymerization method of the silicone compound has no adverse effect on the viscosity of the system after dispersion; the dispersion problem of the inorganic nucleating agent is solved, and it has good compatibility with the system, and there is no problem of precipitation / separation and stratification during storage / transportation.

[0036] According to some embodiments of the present invention, the silicone compound includes at least one of a silicate compound or a silane compound.

[0037] According to some embodiments of the present invention, the silicate compound includes at least one of tetraethyl orthosilicate, tetrabutyl orthosilicate, diethyl silicate, triethyl silicate, tetraethyl silicate, dimethyl silicate, trimethyl silicate, tetramethyl silicate, diisopropyl silicate, tetraisopropyl silicate, or tetraphenyl silicate.

[0038] According to some embodiments of the present invention, the silane compound includes at least one of hexachloroethylsilane, methyltriethoxysilane, dichlorosilane, trichlorosilane, or hexachloroethylsilane.

[0039] According to some embodiments of the present invention, in step S1, the pH value in the hydrolysis reaction is 7.1 - 8.0. Thus, the occurrence of the hydrolysis reaction can be further promoted in step S1.

[0040] According to some embodiments of the present invention, in step S1, the pH value in the hydrolysis reaction is 7.5 - 7.8. Thus, the hydrolysis reaction has the best effect.

[0041] According to some embodiments of the present invention, in step S2, the pH value in the reaction is 8.1 - 14. Thus, it is convenient to generate silicon dioxide nanoparticles in a strong alkaline environment.

[0042] According to some embodiments of the present invention, in step S2, the pH value in the reaction is 8.5 - 9. Thus, it is convenient to promote the condensation and polymerization reactions to generate silicon dioxide nanoparticles with better dispersibility and stability.

[0043] According to some embodiments of the present invention, in step S2, the temperature of the reaction is 20°C - 50°C. If the temperature is too low, it will affect the system viscosity and reaction rate. If the temperature is too high, the efficiency of the alkaline catalyst will be reduced. Thus, when the reaction temperature is within the range of the present invention, it has a better effect.

[0044] According to some embodiments of the present invention, in step S2, the reaction time is 20 min - 40 min. If the reaction time is too short, the reaction will be incomplete and there will be few nucleating agents. If the time is too long, it will affect the production efficiency. Thus, when the reaction time is within the above range, it has a better effect.

[0045] The third aspect of the present invention provides a polyurethane foam prepared by the above - described method.

[0046] Since the polyurethane foam adopts all the technical solutions of the polyurethane foam preparation method in the above embodiments, therefore, it has at least the technical effects brought by the above - implemented technical solutions. That is, the polyurethane foam has a low thermal conductivity and good heat - insulation effect.

[0047] In a fourth aspect of the present invention, there is provided a refrigerator including a heat insulating material, and the heat insulating material includes the polyurethane foam as described above.

[0048] Since the application adopts all the technical solutions of the polyurethane foam in the above embodiment, therefore, it has at least the technical effects brought by the technical solutions of the above embodiment. That is, the refrigerator has good heat preservation and heat insulation effects.

[0049] Other features and advantages of the present invention will be described in the following specification, and, in part, will be obvious from the specification, or will be understood by practicing the present invention. Detailed Embodiments

[0050] The following will clearly and completely describe the concept of the present invention and the technical effects generated in combination with embodiments to fully understand the purpose, features and effects of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, other embodiments obtained by those skilled in the art without creative efforts fall within the scope of protection of the present invention.

[0051] In the description of the present invention, the description with reference to terms such as "one embodiment", "some embodiments", "schematic embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0052] In some embodiments of the present invention, there is provided a polyurethane foam composition, and the composition contains a polyol composition and an isocyanate composition stored in a mixed manner or independently. The polyol composition includes the following raw materials:

[0053] Polyester polyol, polyether polyol, basic catalyst, emulsifier, silicone compound, blowing agent and water; calculated based on the total content of polyester polyol and polyether polyol being 100 parts by weight, the content of the basic catalyst is 0.3 parts by weight to 5.0 parts by weight, the content of the silicone compound is 0.5 parts by weight to 12 parts by weight, the content of the emulsifier is 0.5 parts by weight to 5 parts by weight; the content of the blowing agent is 13 parts by weight to 50 parts by weight; the content of water is 2 parts by weight to 6 parts by weight;

[0054] The isocyanate composition includes isocyanate; the dosage of the isocyanate composition is 100 parts by weight to 150 parts by weight.

[0055] It is understandable that in existing polyurethane foams, perfluorinated compounds or inorganic powder materials are generally directly added as nucleating additives. Fluorine-based nucleating agents are expensive and have poor compatibility with the system, and there are precipitation problems during use / storage. Direct addition of inorganic nucleating agents also has problems such as high density, difficult dispersion, and sedimentation, resulting in poor thermal insulation performance of the prepared polyurethane foam.

[0056] Furthermore, the polyurethane foam composition provided by the present invention, through the action of components such as polyester polyol, polyether polyol, basic catalyst, emulsifier, silicone compound, foaming agent, and water, has a low thermal conductivity, has no adverse effect on the system viscosity, does not affect the subsequent processing process, and there are no problems of precipitation / separation during storage / transportation; and the polyurethane foam prepared with the composition of the present invention has high thermal insulation performance.

[0057] In some embodiments of the present invention, the basic catalyst includes at least one of organic amine catalysts and basic metal catalysts.

[0058] In some embodiments of the present invention, the basic catalyst includes at least one of organic amine catalysts and basic metal catalysts.

[0059] In some embodiments of the present invention, the organic amine catalyst includes at least one of pentamethyldiethylenetriamine, N,N-dimethylcyclohexylamine, methyldiethanolamine, trimethylethylenediamine, triethylenetetramine, diethylenetriamine, diethylenediamine, ethylenediamine, or triethylenepentamine.

[0060] In some embodiments of the present invention, the basic metal catalyst includes at least one of organotin catalysts, organoantimony catalysts, organocobalt catalysts, organozirconium catalysts, or organobismuth catalysts.

[0061] In some embodiments of the present invention, the foaming agent includes at least one of physical foaming agents and chemical foaming agents.

[0062] It is understandable that the foaming agent of the present invention is selected from one or more of the following: water, various hydrocarbons, various hydrofluorocarbons, various hydrofluoroolefins, formic acid, inert gases, various chemical foaming agents that produce nitrogen or carbon dioxide under foaming reaction conditions, etc.; and mixtures thereof.

[0063] Chemical foaming agents (such as water) can be used alone or in combination with other chemical and physical foaming agents. Also suitable as chemical foaming agents are organic carboxylic acids, such as formic acid, acetic acid, oxalic acid, and carboxyl-containing compounds.

[0064] Physical blowing agents can be used, such as low-boiling hydrocarbons, for example, industrial-grade mixtures of heptane, hexane, n-pentane and isopentane, n-pentane and isopentane, and n-butane and isobutane with propane; cycloalkanes, such as cyclopentane, cyclohexane; low-boiling ethers, such as furan, dimethyl ether and diethyl ether; low-boiling ketones, such as acetone and methyl ethyl ketone; alkyl carboxylates, such as methyl formate, dimethyl oxalate and vinyl lactate; various hydrochlorofluorocarbons (HCFCs), hydrofluorocarbons (HFCs) and hydrofluoroolefins (HFOs), such as 1,1-dichloro-2,2,2-trifluoroethane, 2,2-dichloro-2-fluoroethane, pentafluoropropane, heptafluoropropane, hexafluorobutene, (E,Z)1,1,1,4,4,4-hexafluoro-2-butene and trans-1-chloro-,3,3,3-trifluoropropene, trans-1,3,3,3-tetrafluoroprop-1-ene, 1,3,3,3-tetrafluoropropene, etc.

[0065] In some embodiments of the present invention, the emulsifier includes a polysiloxane emulsifier or a non-polysiloxane emulsifier.

[0066] It can be understood that the function of the emulsifier is to dissolve the blowing agent and stabilize the cell structure.

[0067] In some embodiments of the present invention, the polyester polyol is generally formed by condensation (or transesterification) of an organic dicarboxylic acid (anhydride or ester) with a polyol (including a diol) or by polymerization of a lactone with a polyol. The polyols used to prepare the polyester polyol are generally diols or triols, and include ethylene glycol, diethylene glycol, polyethylene glycol such as PEG 200, propylene glycol, dipropylene glycol, polypropylene glycol, butanediol, pentanediol or hexanediol, polyether polyol, glycerol, etc. The polyfunctional carboxylic acids are selected from the following: succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, decane dicarboxylic acid, maleic acid, fumaric acid and phthalic acid, isophthalic acid, terephthalic acid, isomeric naphthalene dicarboxylic acid, and combinations thereof.

[0068] In some embodiments of the present invention, the hydroxyl value of the polyester polyol is 300 to 500 mgKOH / g. It includes all individual values and sub-ranges from 300 to 500; for example, the hydroxyl value of the polyester polyol is 300 mgKOH / g, 310 mgKOH / g, 320 mgKOH / g, 330 mgKOH / g, 350 mgKOH / g, 360 mgKOH / g, 380 mgKOH / g, 400 mgKOH / g, 420 mgKOH / g, 440 mgKOH / g, 460 mgKOH / g, 480 mgKOH / g, 500 mgKOH / g or the range values composed of any two of them.

[0069] In some embodiments of the present invention, the polyether polyol is a hydroxyl-terminated oligomer, and the hydroxyl groups on the main chain are connected by ether bonds. It is formed by ring-opening polymerization of low-molecular-weight polyols, polyamines or compounds containing active hydrogen as initiators with alkylene oxides under the action of a catalyst. For example, the alkylene oxides are mainly propylene oxide (epoxy propane) and ethylene oxide (epoxy ethane). For example, the polyol initiators include diols such as propylene glycol and ethylene glycol, triols such as glycerol and trimethylolpropane, and pentaerythritol, xylitol, sorbitol, sucrose, etc.; for example, the amine initiators are diethylamine, diethylenetriamine, etc.

[0070] In some embodiments of the present invention, the hydroxyl value of the polyether polyol is 300 - 500 mgKOH / g. It includes all individual values and sub-ranges from 300 to 500; for example, the hydroxyl value of the polyester polyol is 300 mgKOH / g, 310 mgKOH / g, 320 mgKOH / g, 330 mgKOH / g, 350 mgKOH / g, 360 mgKOH / g, 380 mgKOH / g, 400 mgKOH / g, 420 mgKOH / g, 440 mgKOH / g, 460 mgKOH / g, 480 mgKOH / g, 500 mgKOH / g or the range value composed of any two of them.

[0071] In some embodiments of the present invention, calculated based on the total weight of the polyether polyol and the polyester polyol being 100 parts, the content of the polyester polyol is 0.5 - 30 parts by weight, and the remainder is the polyether polyol.

[0072] Furthermore, the content of the polyester polyol includes any value, all ranges and any sub-ranges therein. For example, it includes 0.5 part by weight, 5 parts by weight, 10 parts by weight, 20 parts by weight, 30 parts by weight, or the sub-range composed of any two of them. Thus, when the content of the polyester polyol is within the above range, the prepared polyurethane foam has good thermal conductivity and high production efficiency.

[0073] In some embodiments of the present invention, the dosage of the isocyanate composition is 100 parts by weight - 150 parts by weight. It includes any value, all ranges and any sub-ranges therein. For example, it includes but is not limited to 100 parts by weight, 110 parts by weight, 120 parts by weight, 130 parts by weight, 140 parts by weight and 150 parts by weight.

[0074] In some embodiments of the present invention, the isocyanate includes aliphatic polyisocyanate, cycloaliphatic polyisocyanate, araliphatic polyisocyanate, aromatic polyisocyanate, or a combination thereof. Examples of the isocyanate used in the present invention include, but are not limited to, polymethylene polyphenyl isocyanate; toluene-2,4- / 2,6-diisocyanate; methylene diphenyl diisocyanate; polymeric MDI; triisocyanatononane; naphthyl diisocyanate; 4,4'-diisocyanatodicyclohexyl-methane; 3-isocyanatomethyl-3,3,5-trimethylcyclohexyl isocyanate (isophorone diisocyanate); tetramethylene diisocyanate; hexamethylene diisocyanate; 2-methyl-pentamethylene diisocyanate; 2,2,4-trimethylhexamethylene diisocyanate; dodecamethylene diisocyanate; 1,4-diisocyanatocyclohexane; 4,4'-diisocyanato-3,3'-dimethyl-dicyclohexylmethane; 4,4'-diisocyanato-2,2-dicyclohexylpropane; 3-isocyanatomethyl-1-methyl-1-isocyanatocyclohexane; 1,3-diisocyanato-2-methylcyclohexane; and combinations thereof, etc.

[0075] In some embodiments of the present invention, a method for preparing a polyurethane foam is provided, and the method includes: mixing each component in the above-mentioned composition:

[0076] Wherein, the operation of mixing each component in the composition includes the following steps:

[0077] S1. Mixing polyester polyol, polyether polyol, a part of basic catalyst, emulsifier, water and silicone compound to carry out a hydrolysis reaction; obtaining intermediate I;

[0078] S2. Adding the remaining basic catalyst, blowing agent and isocyanate composition to the intermediate I for foaming to obtain the product.

[0079] It can be understood that: in the present invention, the silicone compound is subjected to a hydrolysis reaction under the action of polyester polyol, polyether polyol, a part of catalyst and water, and then the remaining basic catalyst, blowing agent and isocyanate composition are added for foaming to obtain the polyurethane foam. The thermal conductivity coefficient of the polyurethane foam is reduced, and the heat insulation performance of the polyurethane foam is improved. This is because the nano-sized gel nucleating agent prepared by the in-situ polymerization method of the silicone compound has no adverse effect on the system viscosity after dispersion; the dispersion problem of the inorganic nucleating agent is solved, and it has good compatibility with the system, and there is no problem of precipitation / phase separation during storage / transportation.

[0080] In addition, the method for preparing the polyurethane foam of the present invention also has the advantages of simple process. It directly polymerizes on the basis of the polyol composition without the need to add other equipment. The in-situ polymerization produces a silica gel nucleating agent with a nanometer particle size, which has little influence on the viscosity of the system and does not affect the foam forming and processing performance. The cost of the in-situ polymerized silica gel nucleating agent is low and it is cheaper than the liquid fluorine-based nucleating agent.

[0081] In some embodiments of the present invention, the organosilicon compound includes at least one of a silicate compound or a silane compound.

[0082] In some embodiments of the present invention, the silicate compound includes at least one of tetraethyl orthosilicate, tetrabutyl silicate, diethyl silicate, triethyl silicate, tetraethyl silicate, dimethyl silicate, trimethyl silicate, tetramethyl silicate, diisopropyl silicate, tetraisopropyl silicate or tetraphenyl silicate.

[0083] In some embodiments of the present invention, the silane compound includes at least one of hexachloroethylsilane, methyltriethoxysilane, dichlorosilane, trichlorosilane, hexachlorodisilane.

[0084] In some embodiments of the present invention, in step S1, the pH value in the hydrolysis reaction is 7.1 to 8.0. Thus, the hydrolysis reaction can be further promoted in step S1.

[0085] In some embodiments of the present invention, in step S1, the pH value in the hydrolysis reaction is 7.5 to 7.8. Thus, the hydrolysis reaction has the best effect.

[0086] In some embodiments of the present invention, in step S2, the pH value in the reaction is 8.1 to 14. Thus, it is convenient to generate silica nanoparticles in a strong alkaline environment.

[0087] In some embodiments of the present invention, in step S2, the pH value in the reaction is 8.5 to 9. Thus, it is convenient to promote the condensation and polymerization reactions to generate silica nanoparticles with better dispersibility and stability.

[0088] In some embodiments of the present invention, in step S2, the temperature of the reaction is 20°C to 50°C. If the temperature is too low, it will affect the system viscosity and reaction rate. If the temperature is too high, it will reduce the efficiency of the catalyst. Thus, when the reaction temperature is within the range of the present invention, it has a better effect.

[0089] In some embodiments of the present invention, in step S2, the reaction time is 20 min to 40 min. If the reaction time is too short, the reaction will be incomplete and the amount of nucleating agent will be small. If the time is too long, it will affect the production efficiency. Thus, when the reaction time is within the above range, it has a better effect.

[0090] In some embodiments of the present invention, a polyurethane foam composition is provided, and the raw materials for preparing the polyurethane foam composition include the nucleating agent described in any one of the above.

[0091] In some embodiments of the present invention, a polyurethane foam is provided, which is prepared by the method of the present invention described above.

[0092] It can be understood that since the polyurethane foam adopts all the technical solutions of the preparation method of the polyurethane foam in the above embodiments, it has at least all the beneficial effects brought by the technical solutions in the above embodiments. That is, the polyurethane foam has a low thermal conductivity and good heat preservation effect.

[0093] In some embodiments of the present invention, a refrigerator is provided, including a heat insulating material, and the heat insulating material includes the polyurethane foam described above.

[0094] It can be understood that since the application adopts all the technical solutions of the polyurethane foam in the above embodiments, it has at least all the beneficial effects brought by the technical solutions in the above embodiments. That is, the refrigerator has good heat preservation and heat insulation effects.

[0095] Unless otherwise specified, the reagent information used in the following specific embodiments is as follows:

[0096] Polyether polyol: NJ8243, Jurong Ningwu New Materials Co., Ltd.;

[0097] Polyester polyol: SP3152, Jurong Ningwu New Materials Co., Ltd.;

[0098] Blowing agent: Honeywell A mixture of 5 parts of LBA and 12 parts of cyclopentane;

[0099] Isocyanate composition: polymethylene polyphenyl isocyanate, purchased from Yantai Wanhua Polyurethane Co., Ltd., with the trade name PM200;

[0100] Catalyst A: pentamethyldiethylenetriamine, commercially available;

[0101] Catalyst B: N,N-dimethylcyclohexylamine, commercially available;

[0102] Catalyst C: methyldiethanolamine, commercially available;

[0103] Catalyst D: diethylenetriamine, commercially available;

[0104] Organic silicon compound A: tetraethyl orthosilicate, commercially available;

[0105] Organic silicon compound B: tetrabutyl orthosilicate, commercially available;

[0106] Organosilicon compound C: hexachloroethylsilane, Ningxia Shenglan Chemical Industry;

[0107] Organosilicon compound D: trichlorosilane, commercially available;

[0108] Emulsifier: silicone oil, Evonik B 8481.

[0109] The technical solution of the present invention will be further described below in combination with specific examples.

[0110] Example 1

[0111] This example provides a polyurethane foam composition, the formulation of which is shown in the composition of Example 1 in Table 1, and the polyurethane foam is prepared by the following method:

[0112] S1. Adjust the pH value of polyether polyol, emulsifier, polyester polyol, catalyst A, water and organosilicon compound to 7.6, and mix them at 40 °C for hydrolysis reaction; stir for 30 min; obtain intermediate I;

[0113] S2. Add the solution of intermediate I to catalyst B and blowing agent, adjust the pH value to 9.0, and stir for 30 min; foam with the isocyanate composition to obtain the product.

[0114] Examples 2-4

[0115] Examples 2-4 provide a series of polyurethane foam compositions, the formulations of which are shown in the compositions of Examples 2-4 in Table 1 respectively, and the polyurethane foams are prepared by the same preparation method as in Example 1.

[0116] Table 1 Examples 1-4 (parts by weight)

[0117]

[0118]

[0119] Examples 5-8

[0120] Examples 5-8 provide a series of polyurethane foam compositions, the formulations of which are shown in the compositions of Examples 5-8 in Table 2 respectively, and the polyurethane foams are prepared by the same preparation method as in Example 1.

[0121] Table 2 Examples 5-8 (parts by weight)

[0122] Example 5 Example 6 Example 7 Example 8 Polyester polyol 10 30 25 25 Polyether polyol 90 70 75 75 Catalyst A 0.1 1 — — Catalyst C — — 0.5 — Catalyst D — — — 0.5 Catalyst B 0.2 4 2.5 2.5 Water 2 6 4.2 4.2 Organosilicon compound A 0.5 12 — — Emulsifier 5 0.5 2 2 Blowing agent 13 50 17 17 Isocyanate composition 150 100 110 110

[0123] Examples 9-12

[0124] Examples 9 to 12 provide a series of polyurethane foam compositions, whose formulations and preparation methods are basically the same as those of Example 1, except that the pH values of the hydrolysis reaction in step S1 in Examples 9 to 12 are 7.1, 7.5, 7.8, and 8.0 in sequence.

[0125] Examples 13 to 16

[0126] Examples 13 to 16 provide a series of polyurethane foam compositions, whose formulations and preparation methods are basically the same as those of Example 1. The difference is that the pH values of the reaction in step S2 in Examples 13 to 16 are 8.1, 8.5, 8.8, and 14 in sequence.

[0127] Comparative Example 1

[0128] Comparative Example 1 provides an industrially mass-produced polyurethane foam, purchased from Hongbaoli Group Co., Ltd., with the brand number H5120.

[0129] Comparative Example 2

[0130] Comparative Example 2 provides a polyurethane foam. The dosage of the polyurethane foam composition in Comparative Example 2 is basically the same as that in Example 1. The difference is that Comparative Example 2 does not contain organosilicon compounds. The specific steps are as follows: After weighing the polyurethane foam raw materials and cooling them to the required temperature, a foaming agent is added. After stirring evenly, a measured nucleating agent (0.1 part by weight, silica HL-450; Huifu Nanomaterials Co., Ltd.) is added, and stirring is continued until uniform. 1.2 times the amount of isocyanate is mixed at a high speed of 5000 revolutions per minute for 5 seconds, then poured into a mold for foaming, and the thermal conductivity is tested.

[0131] Comparative Example 3

[0132] Comparative Example 3 provides a polyurethane foam, whose formulation and preparation method of the polyurethane foam are basically the same as those of Example 1, except that the pH values of the reaction systems in steps S1 and S2 during the preparation process are both 7.0.

[0133] Comparative Example 4

[0134] Comparative Example 4 provides a polyurethane foam, whose formulation and preparation method of the polyurethane foam are basically the same as those of Example 1, except that the pH values of the reaction systems in steps S1 and S2 during the preparation process are both 10.

[0135] Performance test

[0136] The thermal conductivities of the polyurethane foams prepared in Examples 1 to 16 and Comparative Examples 1 to 4 of the present invention are tested. The test method refers to GB / T10295-2008, and the results are shown in Table 3.

[0137] Table 3 Thermal Conductivity of Examples 1-16 and Comparative Examples 1-4

[0138]

[0139]

[0140] It can be seen from the data in Table 1 that the polyurethane foam prepared by using the polyurethane foam composition of the present invention has a low thermal conductivity, improving the heat insulation performance of the polyurethane foam.

[0141] In addition, the nucleating agent in the form of nano-scale silica gel is generated by the in-situ reaction of the hydrolysis of the silicone compound, so that there is no adverse effect on the viscosity of the system after dispersion, and it does not affect the subsequent foam processing and forming performance; there is no problem of precipitation / separation and stratification during storage / transportation.

[0142] The above has made a detailed description in conjunction with the embodiments of the present invention, but the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those of ordinary skill in the art, various changes can also be made without departing from the gist of the present invention.

Claims

1. A polyurethane foam composition, characterized in that, the composition contains a polyol composition and an isocyanate composition stored mixed or separately. The polyol composition includes the following raw materials: polyester polyol, polyether polyol, basic catalyst, emulsifier, silicone compound, blowing agent and water; calculated based on the total content of polyester polyol and polyether polyol being 100 parts by weight, the content of the basic catalyst is 0.3 parts by weight to 5.0 parts by weight, the content of the silicone compound is 0.5 parts by weight to 12 parts by weight, the content of the emulsifier is 0.5 parts by weight to 5 parts by weight; the content of the blowing agent is 13 parts by weight to 50 parts by weight; the content of the water is 2 parts by weight to 6 parts by weight; the isocyanate composition includes isocyanate; the dosage of the isocyanate composition is 100 parts by weight to 150 parts by weight.

2. The polyurethane foam composition according to claim 1, characterized in that, the basic catalyst includes at least one of organic amine catalysts and basic metal catalysts.

3. The polyurethane foam composition according to claim 1, characterized in that, the blowing agent includes at least one of physical blowing agents and chemical blowing agents.

4. A method for preparing polyurethane foam, characterized in that, the method includes: mixing the components in the composition according to any one of claims 1 to 3: wherein, the operation of mixing the components in the composition includes the following steps: S1. Mix polyester polyol, polyether polyol, part of the basic catalyst, emulsifier, water and silicone compound for hydrolysis reaction; obtain intermediate I; S2. Add the remaining basic catalyst, blowing agent and isocyanate composition to the intermediate I for foaming to obtain the product.

5. The method for preparing polyurethane foam according to claim 4, characterized in that, the silicone compound includes at least one of silicate compounds or silane compounds.

6. The method for polyurethane foam according to claim 5, characterized in that, the silicate compounds include at least one of tetraethyl orthosilicate, tetrabutyl silicate, diethyl silicate, triethyl silicate, tetraethyl silicate, dimethyl silicate, trimethyl silicate, tetramethyl silicate, diisopropyl silicate, tetraisopropyl silicate or tetraphenyl silicate; the silane compounds include at least one of hexachloroethylsilane, methyltriethoxysilane, dichlorosilane, trichlorosilane or hexachloroethylsilane.

7. The method for polyurethane foam according to claim 4, characterized in that, in step S1, the pH value in the hydrolysis reaction is 7.1 to 8.0; the time of the hydrolysis reaction is 20 min to 40 min.

8. The method for polyurethane foam according to claim 4, characterized in that, in step S2, the temperature of the reaction is 20 °C to 50 °C.

9. The method for polyurethane foam according to claim 4, characterized in that, in step S2, the pH value in the reaction is 8.1 to 14; the time of the reaction is 20 min to 40 min.

10. A polyurethane foam, characterized in that, Prepared by the method according to any one of claims 4 to 9.

11. A refrigerator, comprising a heat insulating material, characterized in that the heat insulating material comprises a polyurethane foam as described in claim 11.

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