Polyurethane foam and preparation method thereof

Abstract

The invention discloses polyurethane foam and a preparation method thereof. The polyurethane foam is prepared by taking a polyol component, a physical foaming agent component and an isocyanate component as raw materials, the physical foaming agent component contains cyclopentadiene, the mass ratio of the cyclopentadiene in the physical foaming agent component is greater than or equal to 3wt%, and the closed porosity of the polyurethane foam is greater than or equal to 90%. The polyurethane foam prepared by adopting the preparation method disclosed by the invention has better lasting heat preservation and heat insulation performance, namely the heat conductivity coefficient of the obtained polyurethane foam is not obviously reduced along with the prolonging of storage time. Meanwhile, the polyurethane foam obtained by the preparation method disclosed by the invention also has relatively good initial heat conduction, relatively low density and relatively good dimensional stability, and is excellent in comprehensive performance.

Description

Technical Field

[0001] The invention belongs to the technical field of organic polymer materials, and in particular relates to polyurethane foam and a preparation method thereof. Background Art

[0002] Whether in the field of construction or in the field of household appliances such as refrigerators and freezers, energy saving is an important indicator for evaluating product characteristics, and one of the keys affecting the energy saving effect is the thermal insulation material used. Among them, rigid polyurethane foam is the main thermal insulation material with good strength, light weight and low thermal conductivity.

[0003] The thermal conductivity of rigid polyurethane foam is mainly related to the base material, pore structure and gas composition inside the pores. Therefore, the thermal conductivity is usually divided into gas phase thermal conductivity, g , solid phase thermal conductivity s , radiative heat conduction rad and convection heat conduction λ con Four parts; among them, the first three are the main influencing factors, especially for the density of 30kg / m 3 About rigid polyurethane foam material, gas phase thermal conductivity λ g The influence ratio is the highest, which is 60-70%. s The influence ratio is second, accounting for 20-30%, and the radiation heat conduction λ rad The impact is even smaller, less than 10%. Therefore, for a rigid polyurethane foam with a specific physical blowing agent system, its thermal conductivity usually fluctuates within a specific range.

[0004] For example, CN105461882A discloses a combined polyether, polyurethane foam, raw material composition and preparation method thereof, which improves the thermal insulation performance of cyclopentane system foam by optimizing the composition of the combined polyether. The initial thermal conductivity of the obtained product is 19.4 to 19.6 mW / (m·K).

[0005] However, low initial thermal conductivity does not mean good long-term thermal insulation, because the movement of gas inside the pores will further cause changes in thermal conductivity. Therefore, the thermal conductivity of polyurethane materials in existing foaming systems tends to increase with the extension of storage time. For example, CN104271650A discloses the changes in thermal conductivity of polyurethane materials in foaming systems such as cyclopentane, including foams containing HCFO or HFO foaming agents and products made from foams containing HCFO or HFO foaming agents. The results show that after aging for 3 months at room temperature, the thermal conductivity of each system increases significantly, that is, the thermal insulation performance decreases significantly.

[0006] Polyurethane materials with good thermal insulation performance not only need to have a lower initial thermal conductivity, but also have a slower thermal insulation performance decay, so as to meet the long-term use requirements of the terminal product.

[0007] Therefore, it is particularly necessary to develop a new blowing agent system to solve the problem of attenuation of thermal insulation performance of polyurethane foam. Summary of the invention

[0008] Purpose of the invention: The purpose of the present invention is to provide a polyurethane foam and a preparation method thereof. The polyurethane foam prepared by the present invention adopts a new foaming agent system, which solves the problem of attenuation of the heat insulation performance of the polyurethane foam.

[0009] Technical solution: The purpose of the present invention is achieved through the following technical solution:

[0010] The invention provides a polyurethane foam, which is prepared by taking a polyol component, a physical foaming agent component and an isocyanate component as raw materials. The physical foaming agent component contains cyclopentadiene, the mass proportion of the cyclopentadiene in the physical foaming agent component is ≥3wt%, and the closed cell rate of the polyurethane foam is ≥90%.

[0011] The applicant has found through research that the physicochemical properties of cyclopentadiene make it possible to be used as a foaming agent for polyurethane foam. At the same time, its chemical reactivity enables it to self-polymerize in the pores to generate cyclopentadiene polymers, such as dicyclopentadiene, tricyclopentadiene, etc., which reduces the heat exchange caused by the movement of gas phase molecules in the pores, thereby hindering the attenuation of thermal insulation performance. That is, the cyclopentadiene of the present invention not only has a foaming effect, but also has the effect of self-polymerizing in the pores to generate cyclopentadiene polymers. However, its self-polymerization behavior in the pores is affected by the amount used. Research has found that when the mass proportion of cyclopentadiene in the physical foaming agent component is ≥3wt%, effective self-polymerization in the pores can be achieved, so as to achieve the beneficial effect of slowing down the attenuation of thermal insulation performance. At the same time, as the amount of cyclopentadiene increases, the improvement effect also increases accordingly. For example, when the mass proportion of cyclopentadiene in the physical foaming agent component is greater than 10wt%, the improvement effect on the long-term thermal conductivity is significant, and the thermal conductivity of the foam after aging will decrease instead of increase. Therefore, the mass proportion of cyclopentadiene in the present invention is 3-100wt%, and more preferably 13-100wt%. In addition, in order to achieve a better lasting improvement effect, the closed cell rate of the polyurethane foam is ≥90%, preferably ≥93%.

[0012] In order to ensure that cyclopentadiene is transformed from liquid phase to gas phase in a timely manner and to form closed-cell foams in a relatively short period of time, the present invention preferably has an average hydroxyl value of the polyol component excluding water > 150 mgKOH / g, and more preferably 200-550 mgKOH / g.

[0013] The polyol component of the present invention can be a conventional composition in the art, generally referring to a mixture rich in hydroxyl (OH) containing polyols, catalysts, foam stabilizers, chemical foaming agents and other substances, and appropriate additives such as colorants, flame retardants, fillers, etc. can be added as required. The above raw material types can be conventional in the art, such as polyols can be selected from at least one of polyether polyols, polyester polyols, bio-based polyols, recycled polyols, etc.

[0014] Preferably, the polyol component further contains a chemical foaming agent, which refers to a compound that can react with isocyanate to generate a gas phase product; the chemical foaming agent is at least one of water or a compound C having an anion that is a carbon dioxide donor. The compound C can be selected from the types currently disclosed in the art, such as at least one selected from formic acid, formates, organic / inorganic carbonates, alcoholamine salts and the like. Further, formates can be selected from ammonium formate, formic acid organic amine salt compounds, orthoformic acid organic amine salt compounds; organic / inorganic carbonates can be selected from carbonate organic amine salt compounds, bicarbonate organic amine salt compounds, hydroxypropylated carbonate ammonium salt compounds; alcoholamine salts can be selected from hydrazine alcoholamine salt compounds, carbonate organic alcoholamine salts and other organic alcoholamine salt compounds.

[0015] The water content of the polyol component used in the present invention can be adjusted according to the application field and demand, and can be used within the existing range in the art. According to the characteristics of the material system containing cyclopentadiene in the present invention, in order to cooperate with it and further promote the uniform distribution of pores, the water content of the polyol component is preferably ≥1.0wt%, more preferably 1.0-3.0wt%, and further preferably 1.6-2.8wt%, and the water content includes the water contained in the raw materials such as polyether polyols, and also includes additionally added water.

[0016] Preferably, the polyol component and / or the physical blowing agent component contains a polymerization inhibitor, and the polymerization inhibitor contains an active group capable of reacting with isocyanate.

[0017] The polymerization inhibitor can prevent cyclopentadiene from self-polymerizing during storage, and the type of the polymerization inhibitor can be conventional in the art, such as free radical compounds, phenols, aromatic amines, quinones, nitro compounds, nitroso compounds, organic sulfides, inorganic compounds, etc. Among them, the free radical compound can be selected from 1,1-diphenyl-2-trinitrophenylhydrazine, dimethoxydiphenyl nitroxide free radical, dinitrodiphenyl nitroxide free radical, di-tert-butyl nitroxide free radical, tetramethyl-p-hydroxypiperidinyl nitroxide free radical, etc.; the inorganic compound type polymerization inhibitor can be selected from nitrogen oxides and salts thereof, high-valent metal salts, variable-valent metal salts, etc.

[0018] However, the present invention still requires cyclopentadiene to self-polymerize in due time. Therefore, in order to reduce the negative impact on the polyurethane reaction of the present invention, ensure that cyclopentadiene is gasified in due time and ensure that cyclopentadiene can achieve self-polymerization in the pores after the polyurethane foam is formed, it is preferred to add a polymerization inhibitor to the polyol component and / or the physical foaming agent component, and the polymerization inhibitor contains an active group that can react with isocyanate, and the active group can be a hydroxyl group and / or an amino group. It is further preferred that the polymerization inhibitor contains phenols and / or aromatic amines. The phenols can be selected from at least one of phenol, tert-butyl hydroquinone, hydroquinone, 2,5-di-tert-butyl hydroquinone, 2,6-di-tert-butyl-p-cresol, etc., and the aromatic amines can be selected from at least one of aniline, diphenylamine, methyl aniline, benzidine, phenylenediamine, phenothiazine, naphthylamine, etc. In particular, when the mass proportion of cyclopentadiene in the physical foaming agent component is greater than 50wt%, the effect of using a polymerization inhibitor is better.

[0019] The amount of polymerization inhibitor used is preferably sufficient to achieve the polymerization inhibition effect. The amount of polymerization inhibitor used in the polyol component or the physical foaming agent component may be ≥1% or <1%. The effect of adding the polymerization inhibitor is to prevent cyclopentadiene from self-polymerizing during the mixing stage, so as to take into account the fluidity of the material. However, since cyclopentadiene needs to self-polymerize after the pores are formed, the content of the polymerization inhibitor cannot be too high.

[0020] In order to allow cyclopentadiene to fully self-polymerize in the pores, it is further preferred that the amount of the inhibitor added is less than 1.0%, such as 0.01-0.5%, based on the total mass of the polyol component; it is preferred that the amount of the inhibitor added is less than 1.0%, such as 0.01-0.5%, based on the total mass of the physical foaming agent component.

[0021] In order to take into account better fluidity and uniformity of pore distribution, it is preferred that the physical foaming agent component also contains alkane compounds, such as alkanes and / or cycloalkanes containing 1 to 6 carbon atoms and a boiling point of less than 50°C, such as methane, ethane, propane, n-butane, isobutane, n-pentane, cyclopentane, neopentane, n-hexane, isohexane, 2,3-dimethylhexane, cyclohexane, etc. In order to better cooperate with cyclopentadiene to obtain a polyurethane foam with excellent comprehensive performance, it is further preferred that the alkane compound is at least one of propane, n-butane, isobutane, cyclopentane, n-pentane, isopentane or neopentane. Furthermore, the alkane compound contains at least cyclopentane.

[0022] Further preferably, the molar ratio of the alkane compound to cyclopentadiene is greater than 1: 1. Studies have found that this molar ratio is beneficial to hindering the self-polymerization of cyclopentadiene during the foaming reaction in the absence of an inhibitor or insufficient amount of an inhibitor, thereby optimizing the cell structure and the gas composition inside the cell and improving thermal insulation performance.

[0023] In the present invention, the molar ratio of the alkane compound to cyclopentadiene can be greater than 1:1 or less than 1:1. When the molar ratio is greater than 1:1, it is to utilize the synergistic effect of the alkane to achieve the polymerization inhibition effect without using a polymerization inhibitor or when the amount of the polymerization inhibitor is insufficient. When the molar ratio is less than 1:1, an appropriate amount of polymerization inhibitor will be used in the system at the same time.

[0024] Furthermore, in order to take into account both low density and good low temperature dimensional stability, it is preferred that the alkane compound is composed of an alkane compound with a boiling point greater than 20°C and an alkane compound with a boiling point less than 10°C, that is, the physical foaming agent component is composed of an alkane compound with a boiling point greater than 20°C, an alkane compound with a boiling point less than 10°C and cyclopentadiene. The alkane compound with a boiling point greater than 20°C can be selected from at least one of cyclopentane, n-pentane and isopentane, and the alkane compound with a boiling point less than 10°C can be selected from at least one of neopentane, n-butane, isobutane and propane.

[0025] The isocyanate component of the present invention can be any conventional one in the art, and generally refers to a component mainly composed of organic isocyanate, which can be composed of organic isocyanate alone, or composed of organic isocyanate and a small amount of inert auxiliary agent, and the inert auxiliary agent can be a physical foaming agent, or a foam stabilizer, etc. Conventional organic isocyanates in the art can be used in the present invention, and can be polymethylene polyphenyl polyisocyanate (abbreviated as polymeric MDI) and / or modified isocyanate. Preferably, the NCO% of the organic isocyanate is 25-32wt%, and the average functionality is greater than 2.5, such as 2.6-3.0, so as to further take into account the crosslinking density and improve the foam strength. Among them, considering the safety and convenience of raw material use, the organic isocyanate can be selected from polymeric MDI, and its NCO% is 30.0-32.0%, and the average functionality is 2.6-3.0, such as PM200, 44v20L, M20s, PM2010, M50, PM400, 44V40L, 2085, PAPI TM 580N. In order to further optimize the initial thermal conductivity requirement, the organic isocyanate may contain a modified isocyanate, such as a modified isocyanate, or a mixture of a modified isocyanate and polymeric MDI. Modified isocyanate generally refers to a substance obtained by reacting a polyol with toluene diisocyanate, diphenylmethane diisocyanate and / or polymethylene polyphenyl polyisocyanate, such as a modified isocyanate with NCO%=18-28wt% and an average functionality of 2.0-2.6. The polyol used can be conventional in the art.

[0026] The material ratio between the polyol component, the physical foaming agent component and the isocyanate component of the present invention is usually based on 100 parts of the polyol component, the amount of the physical foaming agent component is determined according to the density of the rigid polyurethane foam, and the amount of the isocyanate component is determined according to the isocyanate index, which refers to the ratio of the molar amount of the reactive group (i.e., NCO group) in the organic isocyanate to the molar amount of the reactive group (i.e., OH group) in the polyol component. The isocyanate index of the present invention can be 1.05 to 3.0, that is, the ratio of the molar amount of the reactive group of the isocyanate component to the molar amount of the reactive group of the polyol component is 1.05 to 3.0. Among them, in order to promote the formation of the trimerization product polyisocyanurate to improve the strength, the isocyanate index is preferably greater than 1.5. Based on this, under the condition of taking into account a wider density selection range and better comprehensive foam performance, the mass ratio of the raw materials of the present invention is preferably polyol component: physical foaming agent: isocyanate component = 100: (10 to 25): (110 to 310).

[0027] The present invention also provides a method for preparing the polyurethane foam. In theory, any conventional method in the art that can be used to prepare rigid polyurethane foam can be used in the present invention. In view of the particularity of the compound cyclopentadiene used in the present invention, in order to ensure that cyclopentadiene is gasified in time during the reaction and can self-polymerize in time in the pores, the present invention lists three embodiments of the preparation method, any of which can be used in the present invention. In order to take into account the convenience of process operation, method one is preferred.

[0028] Mode 1: The preparation method of the polyurethane foam described in the present invention comprises the following steps: mixing a polyol component with a physical blowing agent containing at least one kind of cyclopentadiene to obtain a mixture A, and then mixing the mixture A with the remaining physical blowing agent and the isocyanate component to carry out a polyurethane foaming reaction, and obtaining a polyurethane foam after the reaction product is cured and formed; the weight of the remaining physical blowing agent includes zero.

[0029] This method is a conventional preparation method in the art. The cyclopentadiene is added by premixing the cyclopentadiene with the polyol component. It is more suitable for the case where the polyol component and / or the physical foaming agent component of the present invention contains an inhibitor. The temperature of the mixture A, the temperature of the isocyanate component and the foaming reaction temperature can all be conventional in the art, such as 5 to 30°C.

[0030] Mode 2: The preparation method of the polyurethane foam described in the present invention comprises the following steps: mixing an isocyanate component with a physical blowing agent containing at least one kind of cyclopentadiene to obtain a mixture B with a temperature of less than 16°C, and then mixing the mixture B with a polyol component and the remaining physical blowing agent to carry out a polyurethane foaming reaction, and obtaining a polyurethane foam after the reaction product is cured and formed, wherein the weight of the remaining physical blowing agent includes zero.

[0031] The method of adding cyclopentadiene in this way is to premix cyclopentadiene with the isocyanate component, which is suitable for the case where there is no inhibitor or the amount of inhibitor added is small, wherein the temperature of the mixture B can be 0-15°C, and the temperature of the polyol component and the temperature of the polyurethane foaming reaction can be used according to the conventional methods in the art.

[0032] Mode three, the preparation method of the polyurethane foam described in the present invention comprises the following steps: mixing an alkane compound with a physical foaming agent containing at least one cyclopentadiene, and then mixing the mixture with a polyol component and an isocyanate component to carry out a polyurethane reaction, and the reaction product is cured and formed to obtain a polyurethane foam.

[0033] The method of adding cyclopentadiene in this way is to premix cyclopentadiene with the alkane compound, which is suitable for the case where a polymerization inhibitor is added and / or no polymerization inhibitor is added. When no polymerization inhibitor is added, the temperature of the mixture obtained after the alkane compound is mixed with the physical foaming agent containing at least cyclopentadiene can also be selected to be low, such as 0-15°C, and the temperature of the polyol component, the temperature of the isocyanate component and the polyurethane foaming reaction temperature can all be used according to the conventional methods in the art.

[0034] Beneficial effects:

[0035] The polyurethane foam prepared by the preparation method of the present invention has good long-lasting thermal insulation performance, that is, the thermal conductivity of the obtained polyurethane foam will not significantly decrease with the extension of storage time. At the same time, the polyurethane foam obtained by the present invention can also take into account good initial thermal conductivity, low density and good dimensional stability, and has excellent comprehensive performance. DETAILED DESCRIPTION

[0036] The technical solution of the present invention is described in detail below through specific embodiments, but the protection scope of the present invention is not limited to the embodiments.

[0037] The polyol components used in the present invention are:

[0038] H9510.6 (hydroxyl value is 200 mgKOH / g, water content is 2.5wt%, and the content of inhibitor hydroquinone is 0.2wt%);

[0039] H9637.6 (hydroxyl value is 273 mgKOH / g, water content is 2.3 wt%, and the content of inhibitor 2,6-di-tert-butyl-p-cresol is 0.15 wt%);

[0040] H9911.6 (hydroxyl value 310 mgKOH / g, water content 3.0 wt%);

[0041] H9063.5 (hydroxyl value is 332 mgKOH / g, water content is 1.6 wt%, carbonic acid organic alcohol amine salt mixture CFA-8125 content is 4%, and inhibitor phenothiazine content is 0.01 wt%);

[0042] H9026.5 (hydroxyl value is 365 mgKOH / g, water content is 2.0 wt%, and the content of inhibitor p-toluidine is 0.3 wt%);

[0043] H9026.7 (hydroxyl value 365 mgKOH / g, water content 2.2 wt%);

[0044] H9658.5 (hydroxyl value 388 mgKOH / g, water content 2.1 wt%);

[0045] H9581.5 (hydroxyl value 415 mgKOH / g, water content 1.0 wt%);

[0046] H9566.2 (hydroxyl value 465 mgKOH / g, water content 2.7 wt%);

[0047] H9519.6 (hydroxyl value 141 mgKOH / g, water content 2.5 wt%);

[0048] H9518.5 (hydroxyl value is 580 mgKOH / g, water content is 2.5 wt%)

[0049] All of them were purchased from Hongbaoli Group Co., Ltd. and all contained polyether polyols, polyester polyols, foam stabilizers, catalysts and water. In addition, the polyol components containing inhibitors have the inhibitor content indicated in brackets, and those without markings have no inhibitor added.

[0050] The isocyanate component used in the present invention is:

[0051] Polymethylene polyphenyl polyisocyanate M20s, nominal NCO% 31.5%, nominal functionality 2.7, BASF;

[0052] Polymethylene polyphenyl polyisocyanate PAPI TM 580N, nominal NCO% 30.8%, nominal functionality 3.0, Dow Chemical;

[0053] Polymethylene polyphenyl polyisocyanate 44v40L, nominal NCO% 32.0%, nominal functionality 2.8, Covestro;

[0054] Modified isocyanate ISO-1#, homemade, using aromatic polyester polyols in a mass ratio of 1:9 PS-2602 and diethylene glycol based polyether polyol VORANOL TM 220-110 modified M20s was prepared, NCO% = 25%, and the average functionality was 2.6;

[0055] The preparation method of modified isocyanate A is as follows: vacuum dehydrating a hydroxyl-containing compound, and then reacting it with an organic isocyanate at 40-70° C. to obtain the modified isocyanate A after the reaction is completed.

[0056] The compound having anions as carbon dioxide donors used in the present invention is: organic alcohol carbonate amine salt mixture CFA-8125, produced by Butian New Material Technology Co., Ltd.

[0057] The physical foaming agent component used in the present invention can be a mixture of all components, or each component can be used alone according to the preparation method. For example, if the physical foaming agent component 4 of the present invention is 97wt% cyclopentane and 3wt% cyclopentadiene, cyclopentadiene and cyclopentane can be mixed to form a mixture for use, or a certain amount of cyclopentane can be added to the polyol component, and the remaining amount of physical foaming agent can be added to the isocyanate component for use. The physical foaming agent components used in the present invention include the following:

[0058] 1# physical foaming agent component: 74wt% cyclopentadiene and 26wt% hexafluoropropylene;

[0059] 2# physical foaming agent component: 41wt% cyclopentane, 9wt% n-butane and 50wt% cyclopentadiene;

[0060] 3# physical foaming agent component: 88.80wt% cyclopentadiene, 11.12wt% isobutane and 0.08wt% inhibitor p-tert-butylcatechol;

[0061] 4# physical foaming agent component: 97wt% cyclopentane and 3wt% cyclopentadiene;

[0062] 5# physical foaming agent component: 42.9wt% cyclopentane, 14.3wt% n-pentane, 4.7wt% propane and 38.1wt% cyclopentadiene;

[0063] 6# physical foaming agent component: 61wt% cyclopentane, 13wt% isopentane and 26wt% cyclopentadiene;

[0064] 7# physical foaming agent component: 63.6wt% cyclopentane, 9.2wt% neopentane, 13.6wt% cyclopentadiene and 13.6wt% 3-fluoropropylene;

[0065] 8# physical foaming agent component: 36.8wt% cyclopentane and 63.2wt% cyclopentadiene;

[0066] 9# physical foaming agent component: 100wt% cyclopentadiene;

[0067] 10# physical foaming agent component: 99.5wt% cyclopentadiene and 0.5wt% inhibitor benzidine;

[0068] 11# physical foaming agent component: 99.5wt% cyclopentadiene and 0.5wt% inhibitor benzoquinone;

[0069] 12# physical foaming agent component: 99.0wt% cyclopentadiene and 1.0wt% inhibitor benzidine;

[0070] D1# physical foaming agent components: 98wt% cyclopentane and 2wt% cyclopentadiene.

[0071] The present invention adopts the following method to characterize the performance of rigid polyurethane foam:

[0072] The closed cell ratio, apparent core density, dimensional stability, thermal conductivity and compressive strength are all carried out in accordance with the method in "GB / T 26689-2024 Rigid polyurethane foam plastics for refrigerators and freezers".

[0073] Density distribution uniformity: It is expressed by the core density range, which is the difference between the maximum core density and the minimum core density measured at different sampling points on the same sample.

[0074] Thermal conductivity decay: With a natural month as the cycle, the thermal conductivity is tested at room temperature for 1 month and 3 months.

[0075] The rigid polyurethane foam of the present invention is prepared by mixing the materials with high-speed stirring, injecting the materials into a mold for curing and molding, wherein the temperature of the materials is 0-30° C., the temperature of the mold is 38-42° C., and the size of the mold cavity is: 1100mm×300mm×50mm.

[0076] Example 1

[0077] According to the mass ratio, polyol component H9510.6:1# physical foaming agent: organic isocyanate PAPI TM 580N=100:23:259 Prepare raw materials, mix H9510.6 with cyclopentadiene to obtain mixture A-1#, the material temperature is 20°C, then mix mixture A-1# with hexafluoropropylene and PAPI TM After mixing at 580N, the mixture was injected into a mold for polyurethane foaming reaction. The reaction product was cured and formed to obtain polyurethane foam, which was recorded as P-1#.

[0078] Example 2

[0079] According to the mass ratio, polyol component H9911.6:2# physical foaming agent: organic isocyanate PAPI TM 580N=100:22:302Prepare raw materials and mix PAPI TM 580N was mixed with cyclopentadiene and n-butane to obtain a mixture B-2#, the material temperature was 5°C, and then the mixture B-2# was mixed with H9911.6 and cyclopentane and injected into a mold for polyurethane foaming reaction. The reaction product was cured and formed to obtain a polyurethane foam, which was recorded as P-2#.

[0080] Example 3

[0081] According to the mass ratio, polyol component H9911.6:3# physical foaming agent: organic isocyanate PAPI TM 580N=100:18:242 Prepare raw materials and mix PAPI TM 580N was mixed with cyclopentadiene, isobutane and p-tert-butylcatechol to obtain a mixture B-3#, the material temperature was 0°C, and then the mixture B-3# was mixed with H9911.6 and injected into a mold for polyurethane foaming reaction. The reaction product was cured and formed to obtain a polyurethane foam, which was recorded as P-3#.

[0082] Example 4

[0083] According to the mass ratio, polyol component H9658.5:4# physical foaming agent: organic isocyanate M20s=100:13.4:138 Prepare raw materials, mix cyclopentane and cyclopentadiene to obtain a foaming agent mixture, the material temperature is 0°C, and then mix the foaming agent mixture with H9658.5, M20s was mixed and injected into the mold for polyurethane foaming reaction. The reaction product was cured and formed to obtain polyurethane foam, which was recorded as P-4#.

[0084] Example 5

[0085] According to the mass ratio, polyol component H9637.6:5# physical foaming agent: organic isocyanate M20s=100:20:148 Prepare raw materials, M20s was mixed with cyclopentadiene, n-pentane and propane to obtain a mixture B-5#, the material temperature was 10°C, and then the mixture B-5# was mixed with H9637.6 and cyclopentane and injected into a mold for polyurethane foaming reaction. The reaction product was cured and formed to obtain a polyurethane foam, which was recorded as P-5#.

[0086] Example 6

[0087] Prepare raw materials according to the mass ratio of polyol component H9566.2:6# physical foaming agent: modified isocyanate ISO-1#=100:23:247, mix cyclopentane, isopentane and cyclopentadiene to obtain a foaming agent mixture, the material temperature is 20°C, and then mix the foaming agent mixture with H9566.2 and modified isocyanate ISO-1# and inject them into a mold for polyurethane reaction. After the reaction product is cured and formed, a polyurethane foam is obtained, which is recorded as P-6#.

[0088] Example 7

[0089] According to the mass ratio, polyol component H9581.5:7# physical foaming agent: organic isocyanate 44v40L=100:22:125 Prepare raw materials, mix cyclopentane, neopentane and cyclopentadiene to obtain a blowing agent mixture, the material temperature is 25°C, and then mix the blowing agent mixture with H9581.5, 3-fluoropropylene and 44v40L was mixed and injected into a mold for polyurethane foaming reaction. The reaction product was cured and formed to obtain polyurethane foam, which was recorded as P-7#.

[0090] Example 8

[0091] According to the mass ratio, polyol component H9063.5:8# physical foaming agent: organic isocyanate PAPI TM 580N=100:19:118 Prepare raw materials and mix PAPI TM 580N was mixed with cyclopentadiene to obtain a mixture B-8#, the material temperature was 2°C, and then the mixture B-8# was mixed with cyclopentane and H9063.5 and injected into a mold for polyurethane foaming reaction. The reaction product was cured and formed to obtain a polyurethane foam, which was recorded as P-8#.

[0092] Example 9

[0093] According to the mass ratio, polyol component H9026.5:9# physical foaming agent: organic isocyanate M20s = 100:21:130 Prepare raw materials, mix H9026.5 with cyclopentadiene to obtain mixture A-9#, the material temperature is 22°C, and then mix mixture A-9# with M20s was mixed and injected into the mold for polyurethane foaming reaction. The reaction product was cured and formed to obtain polyurethane foam, which was recorded as P-9#.

[0094] Example 10

[0095] According to the mass ratio, polyol component H9026.7:10# physical foaming agent component: organic isocyanate M20s = 100: 11.1: 134 Prepare the raw materials, mix H9026.7 with cyclopentadiene and benzidine to obtain a mixture A-10#, the material temperature is 22°C, and then mix the mixture A-10# with M20s was mixed and injected into the mold for polyurethane foaming reaction. The reaction product was cured and formed to obtain polyurethane foam, which was recorded as P-10#.

[0096] Embodiment 11

[0097] According to the mass ratio, polyol component H9026.7:11# physical foaming agent component: organic isocyanate M20s=100:11.1:134 Prepare raw materials, mix H9026.7 with cyclopentadiene and benzoquinone to obtain mixture A-11#, the material temperature is 22°C, and then mix mixture A-11# with M20s was mixed and injected into the mold for polyurethane foaming reaction. The reaction product was cured and formed to obtain polyurethane foam, which was recorded as P-11#.

[0098] Example 12

[0099] According to the mass ratio, polyol component H9026.7:12# physical foaming agent component: organic isocyanate M20s=100:11.1:134 Prepare raw materials, mix H9026.7 with cyclopentadiene and benzidine to obtain mixture A-12#, the material temperature is 22°C, and then mix mixture A-12# with M20s was mixed and injected into the mold for polyurethane foaming reaction. The reaction product was cured and formed to obtain polyurethane foam, which was recorded as P-12#.

[0100] Comparative Example 1

[0101] According to the mass ratio, polyol component H9658.5: cyclopentane: organic isocyanate M20s=100:15:138 Prepare the raw materials, adjust the temperature of cyclopentane to 0℃, and then mix with H9658.5, M20s was mixed and injected into the mold for polyurethane foaming reaction. The reaction product was cured and formed to obtain polyurethane foam, which was recorded as P-D1#.

[0102] Comparative Example 2

[0103] According to the mass ratio, polyol component H9911.6: cyclopentane: n-butane: organic isocyanate PAPI TM 580N=100:17:2:242 Prepare raw materials and mix PAPI TM580N was mixed with n-butane to obtain a mixture B-D2#, the material temperature was 5°C, and then the mixture B-D2# was mixed with H9911.6 and cyclopentane and injected into a mold for polyurethane foaming reaction. The reaction product was cured and formed to obtain a polyurethane foam, which was recorded as P-D2#.

[0104] Comparative Example 3

[0105] According to the mass ratio, polyol component H9658.5:D1# physical foaming agent: organic isocyanate M20s=100:15.3:138 Prepare raw materials, mix cyclopentane and cyclopentadiene to obtain a foaming agent mixture, the material temperature is 0°C, and then mix the foaming agent mixture with H9658.5, M20s was mixed and injected into the mold for polyurethane foaming reaction. The reaction product was cured and formed to obtain polyurethane foam, which was recorded as P-D3#.

[0106] Comparative Example 4

[0107] According to the mass ratio, polyol component H9658.5:9# physical foaming agent: organic isocyanate M20s = 100:21:138 Prepare raw materials, mix H9658.5 with cyclopentadiene to obtain mixture A-D4#, the material temperature is 22°C, and then mix mixture A-D4# with M20s was mixed and injected into the mold for polyurethane foaming reaction. The reaction product was cured and formed to obtain polyurethane foam, which was recorded as P-D4#.

[0108] Comparative Example 5

[0109] According to the mass ratio, polyol component H9519.6: 1# physical foaming agent: organic isocyanate PAPI TM 580N=100:23:216 Prepare raw materials, mix H9519.6 with cyclopentadiene to obtain mixture A-D5#, the material temperature is 20°C, then mix mixture A-D5# with hexafluoropropylene and PAPI TM After mixing at 580N, it was injected into the mold for polyurethane foaming reaction. The reaction product was cured and formed to obtain polyurethane foam, which was recorded as P-D5#.

[0110] Comparative Example 6

[0111] According to the mass ratio, polyol component H9518.5:10# physical foaming agent component: organic isocyanate M20s = 100: 11.1: 196 Prepare raw materials, mix H9518.5 with cyclopentadiene and benzidine to obtain mixture A-D6#, the material temperature is 22°C, and then mix mixture A-D6# with M20s was mixed and injected into the mold for polyurethane foaming reaction. The reaction product was cured and formed to obtain polyurethane foam, which was recorded as P-D6#.

[0112] The properties of the rigid polyurethane foams prepared in the examples and comparative examples were characterized. The results are shown in Tables 1 and 2.

[0113] Table 1 Characterization results of P-1#~P-8# rigid polyurethane foam properties

[0114]

[0115] Table 2 Characterization results of P-9#~P-D6# rigid polyurethane foam performance

[0116]

[0117] From the data in the table, it can be seen that the thermal conductivity of the rigid polyurethane foam prepared by the preparation method of the present invention has a low long-term thermal conductivity. During the aging process at room temperature, its thermal conductivity does not increase, and even shows a decreasing trend, which has good thermal conductivity aging performance. At the same time, the rigid polyurethane foam of the present invention can also take into account good comprehensive foam performance. However, the thermal insulation performance of the rigid polyurethane foam prepared by Comparative Examples 1 and 2 without using the cyclopentadiene system decays rapidly; although Comparative Example 3 uses cyclopentadiene, the amount is too small, and the improvement effect on the problem of thermal insulation performance decay is not obvious; although Comparative Example 4 uses cyclopentadiene, no inhibition measures are taken, and timely inhibition and self-polymerization of cyclopentadiene are not achieved, so the core density and initial thermal conductivity are high, and the density distribution uniformity is poor; the hydroxyl value of the polyol component used in Comparative Examples 5 and 6 is too low or too high, which is not conducive to the rapid formation of uniformly distributed pores, and the comprehensive foam performance is poor.

[0118] As described above, although the present invention has been shown and described with reference to specific preferred embodiments, it should not be construed as limiting the present invention itself. Various changes in form and details may be made without departing from the spirit and scope of the present invention as defined in the appended claims.

Claims

1. Polyurethane foam, prepared from a polyol component, a physical blowing agent component and an isocyanate component as raw materials, characterized in that: The physical foaming agent component contains cyclopentadiene, the mass proportion of the cyclopentadiene in the physical foaming agent component is ≥3wt%, and the closed cell rate of the polyurethane foam is ≥90%.

2. The polyurethane foam according to claim 1, characterized in that The average hydroxyl value of the polyol component excluding water is greater than 150 mgKOH / g.

3. The polyurethane foam according to claim 1, characterized in that The polyol component also contains a chemical blowing agent which is at least one of water or a compound having an anion that is a carbon dioxide donor.

4. The polyurethane foam according to claim 3, characterized in that The water content of the polyol component ≥1.0wt%.

5. The polyurethane foam according to claim 1, characterized in that The polyol component and / or the physical blowing agent component contains a polymerization inhibitor, and the polymerization inhibitor contains an active group capable of reacting with isocyanate.

6. The polyurethane foam according to claim 1, characterized in that The physical foaming agent component also contains an alkane compound; the alkane compound is at least one of propane, n-butane, isobutane, cyclopentane, n-pentane, isopentane or neopentane.

7. The polyurethane foam according to claim 6, characterized in that The molar ratio of the alkane compound to cyclopentadiene is greater than 1:

1.

8. The polyurethane foam according to claim 7, characterized in that The physical foaming agent component consists of an alkane compound with a boiling point greater than 20° C., an alkane compound with a boiling point less than 10° C. and cyclopentadiene.

9. The polyurethane foam according to claim 1, characterized in that The mass ratio of the polyol component, the physical foaming agent component and the isocyanate component is 100:(10-25):(110-310).

10. The method for preparing a polyurethane foam according to any one of claims 1 to 9, characterized in that: The preparation method is any one of method 1, method 2 or method 3: The first method comprises the following steps: mixing a polyol component with a physical blowing agent containing at least cyclopentadiene to obtain a mixture A, and then mixing the mixture A with the remaining physical blowing agent and the isocyanate component to carry out a polyurethane foaming reaction, and curing and molding the reaction product to obtain a polyurethane foam; the weight of the remaining physical blowing agent includes zero; The second method comprises the following steps: mixing an isocyanate component with a physical blowing agent containing at least one kind of cyclopentadiene to obtain a mixture B with a temperature less than 16°C, then mixing the mixture B with a polyol component and the remaining physical blowing agent to carry out a polyurethane foaming reaction, and curing and molding the reaction product to obtain a polyurethane foam; the weight of the remaining physical blowing agent includes zero; The third method comprises the following steps: mixing an alkane compound with a physical foaming agent containing at least cyclopentadiene, and then mixing the mixture with a polyol component and an isocyanate component to carry out a polyurethane reaction, and curing and molding the reaction product to obtain a polyurethane foam.

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