Rigid polyurethane foam material and preparation method thereof

Abstract

The invention discloses a rigid polyurethane foam material and a preparation method thereof. The rigid polyurethane foam material is prepared from the following raw materials in parts by mass: 100 parts of polyol, 2-6 parts of a surfactant, 2-6 parts of a catalyst, 2.2-3.5 parts of water, 14-20 parts of a pentane foaming agent, 1.8-4 parts of a butane foaming agent and 140-170 parts of polyisocyanate, and has the performance advantages of low core density, quick demolding, low heat conductivity coefficient and the like; meanwhile, the foam strength, economical efficiency and environmental friendliness are considered, and the foam can be used for preparing foaming thermal insulation materials of household appliances such as refrigerators. The invention also provides a preparation method of the rigid polyurethane foam material.

Description

Technical Field

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

[0002] Rigid polyurethane (PU) foam material has good thermal insulation and cold preservation properties and is widely used in cold preservation products such as refrigerators / freezers. Polyurethane foam is mainly obtained by mixing white material (mainly polyol component) and black material (mainly isocyanate component) and then foaming and curing. In the context of energy conservation and emission reduction, based on product efficiency and cost drive, the development of low thermal conductivity, fast demoulding, low density polyurethane foam has gradually become a research hotspot in the field of thermal insulation materials in recent years.

[0003] With the increasing concern about climate and environmental changes, existing research is trying to develop halogen-free blowing agents to replace traditional halogen-containing blowing agents. However, polyurethane foams prepared using halogen-free blowing agents still face many challenges in practical applications, such as high foam density, low strength, poor thermal insulation performance, etc., which are difficult to meet practical application requirements.

[0004] Therefore, how to develop a polyurethane foam that does not use halogen-containing foaming agents and takes into account both environmental protection and application performance has become a technical problem that needs to be solved urgently. 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, the present invention provides a rigid polyurethane foam material having the performance characteristics of low core density, rapid demoulding, low thermal conductivity, etc., while ensuring foam strength, and having the advantages of environmental protection and low cost.

[0006] The present invention also provides a method for preparing the rigid polyurethane foam material.

[0007] The present invention also provides the application of the above-mentioned rigid polyurethane foam material.

[0008] The first aspect of the present invention relates to a rigid polyurethane foam material, comprising the following raw materials in parts by mass: 100 parts of polyol, 2 to 6 parts of surfactant, 2 to 6 parts of catalyst, 2.2 to 3.5 parts of water, 14 to 20 parts of pentane foaming agent, 1.8 to 4 parts of butane foaming agent, and 140 to 170 parts of polyisocyanate.

[0009] The rigid polyurethane foam material according to the first embodiment of the present invention has at least the following beneficial effects:

[0010] By using pentane compounds as the main foaming agent, low-boiling point butane foaming agents as auxiliary foaming agents, and appropriately increasing the amount of chemical foaming agent water, polyurethane foam with low thermal conductivity, low density, and rapid demoulding can be obtained.

[0011] Thermal conductivity is mainly determined by the solid phase thermal conductivity brought by the polyurethane matrix and the gas phase thermal conductivity brought by the foaming agent gas. Using a high mass fraction of water may be beneficial to promoting the nucleation of bubbles during the foaming process, thereby reducing the bubble size, extending the heat transfer path in the solid part, and reducing the solid phase thermal conductivity, thereby to a certain extent compensating for the disadvantage of the increase in gas phase thermal conductivity caused by the higher thermal conductivity of the foaming agent itself than the fluorine-containing foaming agent, thereby maintaining the performance advantages of the existing polyurethane foam using fluorine-containing foaming agents. The existing way to promote bubble nucleation is to add nucleating agents (divided into particles and low surface energy liquids). Due to the high viscosity of polyols, particle nucleating agents are difficult to disperse evenly; low surface energy liquid nucleating agents, such as perfluorohexene, have poor compatibility with polyol components and are on the restricted use list of the EU ban. In comparison, the use of water nucleation can, on the one hand, reduce the pore size at the same foam density (equivalent to increasing the absolute number of pores) and reduce the solid-phase thermal conductivity of the foam; on the other hand, the carbon dioxide produced by the reaction of water and isocyanate has a lower boiling point and a higher saturated vapor pressure, which is beneficial to increasing the internal pressure of the pores, thereby obtaining high compressive strength at a lower foam core density.

[0012] Butane foaming agents have a low boiling point and can provide greater internal pressure for the pores, which is beneficial to improve the overall strength of the foam by increasing the vapor pressure in the pores at a lower foam core density, thereby meeting the long-term use requirements of products such as refrigerators / freezers. Compared with the original fluorine-containing low-boiling point foaming agents (such as LBA, HFC-152a, GBA, FEA-1150, HFC-134a, HFC-245fa, etc.), butane foaming agents (such as n-butane and isobutane) have the advantages of small molecular weight and low unit price. At the same time, they also increase the amount of water used, which can effectively reduce the cost of foaming materials. While ensuring the foam performance, it further reduces the production cost of the foam and improves the overall competitiveness of the product.

[0013] Compared with butane foaming agents, pentane foaming agents have low gas phase thermal conductivity, which is beneficial to improving the thermal conductivity of foam, but pentane foaming agents have a high boiling point. By adjusting the foaming agent ratio (the ratio of pentane, butane and water, where pentane and butane substances can form azeotropes to improve foam strength), the role of pentane foaming agents in improving thermal conductivity and the role of butane foaming agents and water in improving foam strength can be fully utilized, and finally a foam product with lower core density, lower thermal conductivity, faster demolding rate and higher compression strength is obtained, which has both cost and environmental advantages.

[0014] This solution does not use fluorinated, chlorinated or other halogen-containing foaming agents, is environmentally friendly, has low ozone depletion potential (ODP) and global warming potential (GWP), is not subject to EU regulations, and meets domestic and foreign market application requirements.

[0015] Surfactants are used to improve the mixing uniformity of components and enhance the uniformity of foaming. Properly controlling the amount of surfactant can stabilize the foam, help give full play to the role of the foaming agent, and form a uniform and fine cell structure.

[0016] According to some embodiments of the present invention, the polyol is selected from one or both of polyether polyols or polyester polyols. Polyether polyols and polyester polyols are two polyols widely used in the polyurethane industry. Generally speaking, polyether polyols have better toughness and water resistance, and polyester polyols have more advantages in mechanical properties and heat resistance. In practical applications, either one of the polyols (including a single polyol system, or a matching system of multiple similar polyols) can be used, or two polyols can be used in combination, and the latter is more likely to achieve a balance of overall performance through the matching of polyols.

[0017] According to some embodiments of the present invention, the polyether polyol is selected from a combination of one or more of a polyether polyol with sucrose as an initiator, a polyether polyol with sorbitol as an initiator, a polyether polyol with toluene diamine as an initiator, and a polyether polyol with glycerol as an initiator. The preparation process of polyurethane rigid foam material involves physical and chemical processes such as the formation reaction of carbamate, foaming reaction, pore formation and growth, and by balancing the above processes, the overall performance can be balanced. Among them, the formation reaction of carbamate mainly involves the chemical reaction between polyol monomers and isocyanates, and the product is the skeleton of polyurethane rigid foam material, which will affect the performance of pore growth, foam fluidity, foam strength, etc. Among them, the polyether polyol (functionality of 4) with toluene diamine as the initiator contains benzene rings, has stronger rigidity, and is conducive to improving the strength of the foam. At the same time, its structure contains tertiary amine groups, which have a certain self-catalytic effect on the reaction of polyols and isocyanate groups, and can improve the reaction activity. However, if its dosage is too high, it may cause the carbamate to be generated too quickly and sacrifice the fluidity of the foam. At the same time, its unit price is relatively high, which is not conducive to cost control; the polyether polyol with sucrose or sorbitol as the initiator has a high average functionality, and the obtained foam has a high degree of crosslinking and high strength, but its excessive dosage will also limit the flow of the foam; the polyol with glycerol as the initiator has a low functionality, and can be used in combination with the aforementioned polyol monomers to provide better fluidity for the foam. Therefore, considering the requirements of reaction activity, cost, strength, fluidity, etc., the above-mentioned polyol monomers can be selected for use in combination to obtain a balance of the above-mentioned related properties and achieve the best effect.

[0018] According to some embodiments of the present invention, the polyether polyol includes a polyether polyol with toluene diamine as an initiator to ensure the reaction activity. Optionally, it also includes one or more of a polyether polyol with sucrose as an initiator, a polyether polyol with sorbitol as an initiator, and a polyether polyol with glycerol as an initiator, so as to obtain a foam material with better performance.

[0019] According to some embodiments of the present invention, in the polyether polyol, the mass ratio of the polyether polyol with toluene diamine as the initiator, the polyether polyol with sucrose as the initiator, the polyether polyol with sorbitol as the initiator, and the polyether polyol with glycerol as the initiator is (20-50): (0-45): (0-30): (0-30). It is understood that one or more of the polyether polyol with sucrose as the initiator, the polyether polyol with sorbitol as the initiator, and the polyether polyol with glycerol as the initiator may not be added. It is understandable that, from the perspective of facilitating performance regulation and optimization, it is preferred to use a variety of polyether polyols, that is, the amount of the polyether polyol with sucrose as the initiator, the polyether polyol with sorbitol as the initiator, and the polyether polyol with glycerol as the initiator is not 0 at the same time.

[0020] Regarding non-limiting examples of the proportions of the polyether polyols, for example, in parts by mass, the polyether polyol using toluenediamine as the initiator is 20 parts, 25 parts, 30 parts, 35 parts, 40 parts, 45 parts, 50 parts, or any value therebetween; the polyether polyol using sucrose as the initiator is 0 parts, 5 parts, 10 parts, 15 parts, 20 parts, 25 parts, 30 parts, 35 parts, 40 parts, 45 parts, or any value therebetween; the polyether polyol using sorbitol as the initiator is 0 parts, 5 parts, 10 parts, 15 parts, 20 parts, 25 parts, 30 parts, or any value therebetween; the polyether polyol using glycerol as the initiator is 0 parts, 1 parts, 5 parts, 10 parts, 15 parts, 20 parts, 25 parts, 30 parts, or any value therebetween. It can be understood that the mass parts listed above are only illustrative, and other values ​​not listed in the range are also applicable. It can be further understood that the subset range between any mass parts listed above and any other subset range not listed within the range are all applicable.

[0021] Specifically, according to the above-listed mass parts, non-limiting examples of polyether polyol ratios can be obtained:

[0022] For example, the mass ratio of the polyether polyol with toluene diamine as the initiator, the polyether polyol with sucrose as the initiator, the polyether polyol with sorbitol as the initiator, and the polyether polyol with glycerol as the initiator is

[0023] (20~50):(5~45):(0~30):(0~30), or (20~50):(0~45):(5~30):(0~30), or

[0024] (20-50):(5-45):(0-30):(1-30), or (20-50):(0-45):(5-30):(1-30), or (20-50):(5-45):(5-30):(1-30); more specifically, the mass ratio is (20-50):(5-45):(5-30):(1-10), or (20-50):(10-45):(10-30):(3-8), or (20-50):(10-45):(10-30):(4-6), which can be selected according to actual application requirements. By using a variety of polyols to reasonably match, the reaction rate, raw material cost and foam performance can be balanced.

[0025] According to some embodiments of the present invention, the polyether polyol includes a polyether polyol with toluene diamine as an initiator, a polyether polyol with sucrose as an initiator, a polyether polyol with sorbitol as an initiator, and a polyether polyol with glycerol as an initiator.

[0026] According to some embodiments of the present invention, in the polyether polyol, the mass ratio of the polyether polyol with toluene diamine as the initiator, the polyether polyol with sucrose as the initiator, the polyether polyol with sorbitol as the initiator, and the polyether polyol with glycerol as the initiator is (4-10):(1-9):(1-6):1. Non-limiting examples include (4-10):(2-9):(1-6):1, (4-10):(4-9):(1-6):1, (4-10):(1-9):(2-6):1, (4-10):(4-9):(2-6):1, etc. The specific ratio can be reasonably selected according to the actual application requirements and the mass parts listed above. Using a certain amount of polyether polyols with toluenediamine as the initiator, polyether polyols with sucrose as the initiator, and polyether polyols with sorbitol as the initiator is beneficial to improving the reaction activity and foam strength. Properly controlling the amount of the above polyols can better balance the reaction activity and foam fluidity. At the same time, while ensuring that the performance meets the requirements, the amount of polyether polyols with toluenediamine as the initiator is reduced as much as possible to control the raw material cost. Adding a certain amount of polyether polyols with glycerol as the initiator can effectively improve the fluidity of the foam and ensure the appearance, production efficiency and process stability.

[0027] According to some embodiments of the present invention, the polyester polyol is selected from phthalic anhydride polyester polyol. Polyester polyol is a product obtained by polycondensation reaction of dicarboxylic acid (or acid anhydride) and diol. Compared with polyester polyols made from alkane dibasic acid, phthalic anhydride polyester polyol is synthesized with aromatic anhydride (such as phthalic anhydride) and diol as raw materials and is widely used in the polyurethane industry. Phthalic anhydride polyester polyol has high reactivity and fast reaction rate. Because it contains a large number of benzene rings in its structure, it can also improve the heat resistance and strength of foam, improve flame retardancy, and significantly improve the toughness and adhesion of foam.

[0028] According to some embodiments of the present invention, based on 100 parts by mass of the polyol, the polyol includes: 80 to 100 parts of polyether polyol and 0 to 20 parts of polyester polyol. In actual use, polyether polyol is mainly used, and a certain number of polyester polyols are used in combination, so as to better take into account the performance requirements of reaction activity, foam strength, thermal insulation performance, adhesion and rapid demoulding. Among them, when the polyester polyol is selected from phthalic anhydride polyester polyol, the pore structure is relatively fine and the thermal conductivity of the foam is relatively low, but due to its low functionality and high reaction heat, the usage amount should not be too high to reduce the expansion deformation of the foam after demoulding, which is conducive to rapid demoulding.

[0029] Wherein, based on 100 parts by mass of the polyol, non-limiting examples of the amount of polyether polyol used include, for example, 80 parts, 85 parts, 90 parts, 95 parts, 100 parts, or any value therebetween; non-limiting examples of the amount of polyester polyol used include, for example, 0 parts, 5 parts, 10 parts, 15 parts, 20 parts, or any value therebetween.

[0030] According to some embodiments of the present invention, based on 100 parts by mass of the polyol, the polyol includes: 80-100 parts of polyether polyol and 0-20 parts of polyester polyol; wherein the polyether polyol includes: 0-45 parts of polyether polyol with sucrose as the initiator, 20-50 parts of polyether polyol with toluene diamine as the initiator, 0-30 parts of polyether polyol with sorbitol as the initiator, and 0-30 parts of polyether polyol with glycerol as the initiator. It can be understood that the specific proportions of the relevant components can be selected by referring to the mass parts listed above and combining the functions of the relevant components.

[0031] As an example, among the polyether polyols, non-limiting examples of polyether polyols using sucrose as the initiator include: NJ-8243, NJ-8238, NJ-8345, NJ-8252, NJ-4502, NJ-8209, etc. from Ningwu New Materials, YD-8310, YD-8315, YD-8345, YD-8350, YD-8666, YD-8669, YD-8260, etc. from Hebei Yadong Chemical, R4110B, R8238, R8243, R6001C, etc. from Shandong Yinuowei, SC-450, SC-455, SC-4110, etc. from Guodu Chemical. Non-limiting examples of polyether polyols using sorbitol as an initiator include: NJ-6045, NJ-6256, NJ-6207, NJ-6206, NJ-6249, NJ-6209, NJ-6305B, NJ-6305C, NJ-

[0032] 6305S, etc., YD-600, YD-635, YD-6205, etc. of Hebei Yadong Chemical, R6048, R6205, R6207, etc. of Shandong Yinuowei, ST-430, ST-480, ST-481, ST-501, etc. of Guodu Chemical. Non-limiting examples of polyether polyols using toluenediamine as initiator include: NJ-410H, NJ-430H, NJ-410HN, NJ-3445, NJ-406A, etc. of Ningwu New Materials, YD-TD440, etc. of Hebei Yadong Chemical, TD-400, TD-400L, TD-400P, TD-401, TD-405, etc. of Guodu Chemical. Non-limiting examples of polyether polyols using glycerol as an initiator include: NJ-301, NJ-302, NJ-303, NJ-304 and the like from Ningwu New Materials.

[0033] Non-limiting examples of polyester polyols include: PS-3152, PS-4051, PS-2352 from Nanjing Stepan Chemical, PE-B503L from Shandong Yinuowei, and the like.

[0034] According to some embodiments of the present invention, the functionality of the polyol is 2 to 8, for example, 2, 3, 4, 5, 6, 7, 8 or any value therebetween.

[0035] According to some embodiments of the present invention, the average hydroxyl value of the polyol is 300-500 mgKOH / g, for example, 300 mgKOH / g2, 350 mgKOH / g, 400 mgKOH / g, 450 mgKOH / g, 500 mgKOH / g or any value therebetween.

[0036] Generally speaking, functionality is positively correlated with crosslinking degree and negatively correlated with fluidity; a high hydroxyl value means higher reactivity and faster reaction speed, which is beneficial to improving production efficiency and foam strength. By controlling the functionality and hydroxyl value of polyols within an appropriate range, it is possible to better balance the requirements of material cost, reactivity, foam fluidity, foam strength, adhesion, and rapid demoulding.

[0037] It should be understood that the specific types, proportions or grades of the polyols listed above do not have exclusive or exhaustive meanings. There are many types of polyols, and different polyol combinations (including different compositions or proportions) may have similar or similar effects. It is easy to refer to the above scheme to select a suitable polyol system. For example, referring to the specific types, grades and proportion ranges of the polyols listed above, select one or more polyol combinations with a functionality of 2 to 8, and control the average hydroxyl value to 300 to 500 mgKOH / g, or select other polyol combinations with similar properties.

[0038] According to some embodiments of the present invention, the catalyst is selected from a combination of at least two of a foaming catalyst, a gel catalyst, and a trimerization catalyst, wherein the foaming catalyst is selected from one or two of pentamethyldiethylenetriamine and bis(dimethylaminoethyl) ether; the gel catalyst is selected from a combination of one or more of N,N-dihexylmethylamine, N,N-dimethylcyclohexylamine, triethylenediamine, dibutyltin dilaurate, and dibutyltin bis(dodecylsulfide); the trimerization catalyst is selected from a combination of one or more of tris(dimethylaminopropyl)hexahydrotriazine, 2-hydroxypropyltrimethylammonium formate, potassium acetate, and potassium isooctanoate.

[0039] Among them, the foaming catalyst is used to promote pore formation, the gelling catalyst accelerates the gelling reaction and plays a role in stabilizing and solidifying the foam, and the trimerization catalyst can increase the foaming rate. The combination of different foaming agents is conducive to the formation of a fine and uniform pore structure.

[0040] According to some embodiments of the present invention, the catalyst includes at least a gel-type catalyst and a trimerization catalyst.

[0041] According to some embodiments of the present invention, the catalyst includes at least two organic amine catalysts. For example, when the catalyst is selected from a composite system of a foaming catalyst, a gel catalyst and a trimerization catalyst, at least one of the foaming catalyst, the gel catalyst and the trimerization catalyst is selected from the corresponding category of organic amines, and at least two organic amine catalysts are included in total.

[0042] Common catalysts are mainly divided into two types: organic amines and organic metals. Among them, organic metal catalysts are relatively more active and more toxic. Therefore, if the requirements are met, organic amine catalysts can be used more or entirely.

[0043] According to some embodiments of the present invention, based on 100 parts by mass of the polyol, the foaming catalyst is 0 to 1 part, for example, 0 part, 0.3 part, 0.5 part, 0.8 part, 1 part or any value therebetween.

[0044] According to some embodiments of the present invention, based on 100 parts by mass of the polyol, the foaming catalyst is 0 to 0.5 parts.

[0045] According to some embodiments of the present invention, based on 100 parts by mass of the polyol, the gel-type catalyst is 1.5 to 5 parts, for example, 1.5 parts, 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, 4.5 parts, 5 parts or any value in between.

[0046] According to some embodiments of the present invention, based on 100 parts by mass of the polyol, the gel-type catalyst is 1.5 to 3 parts.

[0047] According to some embodiments of the present invention, based on 100 parts by mass of the polyol, the gel-type catalyst is 2 to 3 parts.

[0048] According to some embodiments of the present invention, based on 100 parts by mass of the polyol, the trimerization catalyst is 0.3 to 3 parts, for example, 0.3 parts, 0.5 parts, 1 parts, 1.5 parts, 2 parts, 2.5 parts, 3 parts or any value in between.

[0049] According to some embodiments of the present invention, based on 100 parts by mass of the polyol, the trimerization catalyst is 0.3 to 1 part.

[0050] According to some embodiments of the present invention, based on 100 parts by mass of the polyol, the trimerization catalyst is 0.5 to 1 part.

[0051] According to some embodiments of the present invention, the catalyst is 2 parts, 3 parts, 4 parts, 5 parts, 6 parts or any value in between, based on 100 parts by mass of the polyol. It is understood that when the catalyst includes multiple of the above-mentioned foaming catalyst, gel catalyst, and trimerization catalyst, the appropriate amount of catalyst can be selected with reference to the above-listed ratio range, and the total mass of the catalyst is 2 to 6 parts / 100 parts of the polyol.

[0052] According to some embodiments of the present invention, based on 100 parts by mass of the polyol, the amount of the catalyst is 2 to 4 parts.

[0053] It should be understood that the types of catalysts or their ratios listed above do not have exclusive or exhaustive meanings. It is easy to select a suitable catalyst system by referring to the above scheme, or to select other catalyst systems with similar properties.

[0054] According to some embodiments of the present invention, the surfactant is selected from an organosilicon surfactant. The surfactant plays a foam stabilizing effect, and foam stabilizers common in the art can be selected, such as organosilicon (non-limiting examples, such as B-8481, B-84813, EP-R-S88, MG-828, MG-945, etc. of Evonik Chemical). The surfactant used in the polyurethane rigid foam industry is mainly two types of non-silicon compounds and organosilicon compounds. Among them, organosilicon surfactants have a wide range of raw material sources and good use effects, and have a positive effect in increasing component compatibility, emulsified materials, stabilizing foam and regulating pores.

[0055] According to some embodiments of the present invention, based on 100 parts by mass of the polyol, the surfactant is 2 parts, 3 parts, 4 parts, 5 parts, 6 parts or any value therebetween.

[0056] According to some embodiments of the present invention, based on 100 parts by mass of the polyol, the amount of the surfactant is 3 to 6 parts.

[0057] According to some embodiments of the present invention, based on 100 parts by mass of the polyol, the water is 2.2 parts, 2.5 parts, 3 parts, 3.5 parts or any value therebetween.

[0058] According to some embodiments of the present invention, based on 100 parts by mass of the polyol, the water is 2.3 to 3.5 parts. Properly increasing the amount of water is more conducive to the nucleation effect of water, reducing the pore size and further reducing the thermal conductivity of the foam.

[0059] According to some embodiments of the present invention, based on 100 parts by mass of the polyol, the water is 2.5 to 3.5 parts.

[0060] According to some embodiments of the present invention, based on 100 parts by mass of the polyol, the water is 2.5 to 3 parts.

[0061] According to some embodiments of the present invention, the pentane foaming agent is selected from cyclopentane, or, the pentane foaming agent is a composition of cyclopentane and isopentane, wherein the cyclopentane is ≥65wt%. When the pentane foaming agent is a composition of cyclopentane and isopentane, the content of cyclopentane can specifically be 65wt%, 70wt%, 75wt%, 80wt%, 85wt%, 90wt%, 95wt%, 99wt% or any value between any two points. Cyclopentane accounts for a high proportion, which is conducive to reducing gas phase thermal conductivity. But cyclopentane has a higher boiling point than isopentane. By adding a certain amount of isopentane (i.e., ≤35wt%), the internal pressure of the pores can be increased, and the compressive strength of the foam can be increased to a certain extent. At the same time, isopentane accounts for a low proportion, and a lower thermal conductivity can also be obtained.

[0062] According to some embodiments of the present invention, the pentane foaming agent is selected from a composition of cyclopentane and isopentane, wherein the mass fraction of cyclopentane is: 70wt%≤cyclopentane≤85wt%, and the specific value can be selected with reference to the numerical values ​​listed above. In contrast, cyclopentane has a lower gas phase thermal conductivity than isopentane. The higher the proportion of cyclopentane, the lower the comprehensive thermal conductivity of the gas in the pores, which is conducive to reducing the thermal conductivity of the foam; the boiling points of cyclopentane and isopentane differ by 21.4 ° C, the boiling point of isopentane is lower, the saturated vapor pressure is high, and a portion of isopentane is used to replace cyclopentane, which is conducive to increasing the gas pressure in the pores, and the strength of the foam can be enhanced at the same foam density. Therefore, using a mixture of cyclopentane and isopentane, and controlling the proportion of cyclopentane in the above range, it is possible to improve the strength of the foam at a considerable density, or reduce the density of the foam at a considerable strength, thereby better taking into account the foam strength and thermal conductivity.

[0063] According to some embodiments of the present invention, based on 100 parts by mass of the polyol, the pentane foaming agent is 14 parts, 15 parts, 16 parts, 17 parts, 18 parts, 19 parts, 20 parts or any value therebetween.

[0064] According to some embodiments of the present invention, the mass of the polyol is 100 parts, and the pentane foaming agent is 16 to 20 parts, and the specific value can be selected with reference to the numerical values ​​listed above. In the raw material system, the foaming agent includes a physical foaming agent and a chemical foaming agent, the physical foaming agent is pentane and butane, the chemical foaming agent is water (finally reacting with isocyanate to produce carbon dioxide filled in the pores), and the gas finally filled in the pores is pentane, butane, and carbon dioxide. Compared with carbon dioxide and butane foaming agents, the gas phase thermal conductivity of pentane foaming agents (especially cyclopentane) is lower, so appropriately increasing the amount of pentane foaming agents helps to reduce the thermal conductivity of the foam; however, the boiling point of pentane foaming agents (such as cyclopentane) is higher, and under the same circumstances, the supporting effect of pentane gas on the pores is weak, therefore, controlling the amount of pentane foaming agents is not too high, which helps to obtain relatively good comprehensive performance.

[0065] According to some embodiments of the present invention, the butane foaming agent is selected from one or both of n-butane and isobutane. N-butane has a high boiling point and a low gas phase thermal conductivity, so the use of n-butane is conducive to improving the thermal conductivity of the foam; isobutane has a low boiling point and is more conducive to ensuring the strength of the foam. From the perspective of thermal conductivity and compression strength, the combination of n-butane and isobutane is more conducive to balancing the above-mentioned multiple performance aspects.

[0066] According to some embodiments of the present invention, the butane foaming agent includes isobutane with a mass fraction of ≥20wt%, for example, the mass fraction of isobutane can be 20wt%, 25wt%, 30wt%, 35wt%, 40wt%, 45wt%, 50wt%, 55wt%, 60wt%, 65wt%, 70wt%, 75wt%, 80wt%, 85wt%, 90wt%, 100wt% or any value between any two points. In order to ensure that the foam still has a high compressive strength at a lower core density to meet the requirements of product production and use, the gas in the pores needs to have a relatively high vapor pressure. In general, the vapor pressure of the gas in the pores is closely related to its boiling point. The lower the boiling point, the higher the vapor pressure. The boiling point of n-butane is -0.5°C, and the boiling point of isobutane is -10.5°C. Using a certain amount of isobutane helps to increase the gas pressure in the pores and enhance the strength of the foam. However, the gas phase thermal conductivity of isobutane is relatively higher than that of n-butane. Therefore, under the premise of comprehensively considering the foam strength and thermal conductivity, a mixture of n-butane and isobutane can be used.

[0067] According to some embodiments of the present invention, the butane foaming agent includes isobutane with a mass fraction of ≥50wt%, for example, the mass fraction of isobutane can be 50wt% to 90wt%, or 50wt% to 80wt%, or 50wt% to 70wt%, or 50wt% to 60wt%.

[0068] According to some embodiments of the present invention, based on 100 parts by mass of the polyol, the butane blowing agent is 1.8 parts, 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts or any value therebetween.

[0069] According to some embodiments of the present invention, based on 100 parts by mass of the polyol, the butane foaming agent is 2.5 to 4 parts.

[0070] According to some embodiments of the present invention, the polyisocyanate is selected from polymethylene polyphenyl isocyanate, also referred to as polymerized MDI, PAPI, crude MDI or PMDI, which is a mixture of polymethylene polyphenyl isocyanates with different functionalities. Compared with MDI (diphenylmethane diisocyanate, solid at room temperature, melting point 39-43°C, functionality 2), polymethylene polyphenyl isocyanate is a low-viscosity liquid at room temperature, with a high average functionality (generally >2.6), and does not need to be heated and melted during use, which is convenient to use, and because of its higher functionality, the foam strength is also higher; compared with TDI (toluene diisocyanate, functionality 2, liquid at room temperature), polymethylene polyphenyl isocyanate has low volatility, high safety, high functionality, and high foam strength. Non-limiting examples of polymethylene polyphenyl isocyanate, for example, the mass fraction of isocyanate is 29wt% to 33wt%, and optional grades include Wanhua Chemical PM-200, PM-2010, PM-300, PM-400, etc., Covestro 44V20, Dow Chemical PAPI27, PAPI135, BASF M20s, M50s, etc.

[0071] According to some embodiments of the present invention, in the raw materials for preparing the rigid polyurethane foam material, the molar ratio of isocyanate to active hydroxyl (or black material index for short) is (1-1.5):1. Wherein, both polyol and water have isocyanate reaction activity, and considering that 1 mol of water consumes 2 mol of isocyanate, the molar number of active hydroxyl is calculated as: the sum of the molar number of hydroxyl in the polyol and twice the molar number of water. Controlling the isocyanate to be equal to or appropriately higher than the chemical equivalent makes the reaction more complete.

[0072] The second embodiment of the present invention relates to a method for preparing the above-mentioned rigid polyurethane foam material, comprising: mixing and reacting raw materials for preparing the rigid polyurethane foam material to obtain the rigid polyurethane foam material.

[0073] The above preparation method is used to prepare the above rigid polyurethane foam material, and therefore, at least has all the beneficial effects of the above embodiments of the rigid polyurethane foam material. Furthermore, the method can produce a rigid polyurethane foam material with low core density, low thermal conductivity, high strength, and rapid demoulding, which can reduce production costs and improve the environmental friendliness of the production process.

[0074] According to some embodiments of the present invention, the raw materials for preparing the rigid polyurethane foam material are mixed, including: mixing A1 part of the pentane foaming agent and B1 part of the butane foaming agent with the raw materials including the polyol, the surfactant, the catalyst and the water to form a white material; mixing the remaining A2 parts of the pentane foaming agent and the remaining B2 parts of the butane foaming agent with the raw materials including the polyisocyanate to form a black material; wherein A1, A2, B1, and B2 are all ≥ 0, and satisfy: A1+A2=14~20, B1+B2=1.8~4; the white material and the black material are mixed and reacted to obtain the rigid polyurethane foam material.

[0075] White material and black material are prepared in advance before the foaming reaction to improve the uniformity of raw material mixing.

[0076] It can be understood that A1, A2, B1, and B2 are all ≥ 0, and do not exceed the upper limit ratio of the corresponding substances (by mass, based on 100 parts of the polyol). It can be understood that B1 and B2 are not 0 at the same time, which means that the butane foaming agent can be added to the white material alone, or a part of it is added to the white material and the rest is added to the black material, or all of it is added to the black material; the situation of the pentane foaming agent is similar. Specifically, it includes but is not limited to the following situations: pentane and butane foaming agents can be all added to the white material; or the pentane foaming agent is all added to the white material, and the butane foaming agent is all added to the black material; or all pentane and a part of the butane foaming agent are added to the white material, and the remaining butane foaming agent is added to the black material; or pentane and butane foaming agents are added to the white material and the black material respectively in a certain proportion; or a part of the pentane foaming agent is added to the white material, and the remaining pentane and all butane foaming agents are added to the black material, etc.

[0077] According to some embodiments of the present invention, A1≥7, for example, A1 is 7, 8, 9, 10, 11, 12, 13, 14 or any value between any two thereof; it can be understood that the value of A1+A2 is 14-20, therefore, according to different values ​​of A1+A2, A1 can also select any other value between 14 and 20. Adding a certain amount of pentane foaming agent to the white material can reduce the viscosity of the white material, facilitate the transportation of the white material, and reduce the impact on the transportation equipment (such as a booster pump).

[0078] According to some embodiments of the present invention, A1 is 8 to 14. Pentane in the white material dilutes the concentration of the catalyst to a certain extent. Therefore, controlling the upper limit content of pentane in the white material is more conducive to ensuring catalytic activity and reducing cell size. In addition, when the polyol contains a type that is not compatible with pentane (for example, polyether polyols with sucrose as an initiator, phthalic anhydride polyester polyols, and polyether polyols with sorbitol as an initiator), controlling the pentane content to be not too high can reduce surface defects.

[0079] According to some embodiments of the present invention, A2>0, for example, A2 is 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 or any value therebetween. That is, adding a certain amount of pentane foaming agent to the black material has two effects: on the one hand, appropriately reducing the amount of pentane foaming agent in the white material, better ensuring the compatibility of the pentane foaming agent with the white material, and the catalyst concentration in the white material, so that the black material and the white material have higher reaction activity, faster reaction, stronger bubble locking ability, and reduce the loss of low-boiling foaming agent; on the other hand, when a butane foaming agent is added to the black material (i.e., B2>0), the pentane foaming agent added to the black material can increase the compatibility of the butane foaming agent in the black material and reduce the surface defects of the foam.

[0080] According to some embodiments of the present invention, B2>0, for example, B2 is 0.5, 1, 2, 3, 4 or any value therebetween. It can be understood that when B2 is 2 to 4, the corresponding total amount of butane foaming agent is not less than 2 to 4 parts. For example, when B2 is 3, the corresponding total amount of butane foaming agent is not less than 3 parts (for example, it can be 4 parts). Because butane foaming agent has better compatibility with black material components, the butane foaming agent is partially or completely added to the black material, which can reduce the surface defects of the foam and improve the surface quality of the foam. It can be understood that adding all the butane foaming agent to the black material (i.e., B1=0) is more conducive to improving the surface quality of the foam.

[0081] According to some embodiments of the present invention, B2>0, A2>0. B2 and A2 can be selected with reference to the values ​​listed above, for example, B2 can be selected as any value between 0.5 and 4; A2 can be selected as any value between 0.5 and 12, for example, specifically 2 to 10, or 2 to 8.

[0082] According to some embodiments of the present invention, A2>0, and B1=0. It can be understood that A2 can be selected with reference to the numerical values ​​listed above.

[0083] According to some embodiments of the present invention, A2>0, A1≥7, and B1=0. A1 and A2 can be selected with reference to the numerical ranges listed above, and can satisfy A1+A2=14-20.

[0084] It should be understood that when the pentane foaming agent is a composition (such as the above-mentioned composition of cyclopentane and isopentane), and is added to both the white material and the black material, the composition of the two parts of the pentane foaming agent may be the same or different, and the difference includes the following situations: one of the white material and the black material is added with a single component (pure cyclopentane or pure isopentane), and the other is added with a composition; or compositions of different compositions are added to the white material and the black material, respectively. From the perspective of convenient production, when a composition is added to both the white material and the black material, the compositions of the two can be the same. Similarly, when the butane foaming agent is a composition (such as the above-mentioned composition of n-butane and isobutane), the feeding method is similar.

[0085] It can be understood that the preparation method of this embodiment is used to prepare the above-mentioned rigid polyurethane foam material. Therefore, regarding the selection of raw materials or their proportions, reference can be made to the above-mentioned embodiment of the rigid polyurethane foam material.

[0086] Among them, when selecting a composition for a pentane / butane foaming agent, for example, the pentane foaming agent is selected from a composition of cyclopentane and isopentane and the cyclopentane is ≥ 65wt%, the proportion of the cyclopentane is calculated by the total mass of cyclopentane to the total mass of the pentane foaming agent. Based on this premise, when the pentane foaming agent is selected from a composition of cyclopentane and isopentane, and the pentane foaming agent is added to both the white material and the black material, the composition of the pentane foaming agent added to the white material or the black material alone may not be restricted by the composition of cyclopentane ≥ 65wt% (the specific value can be selected with reference to the numerical values ​​listed above), and finally the total mass of cyclopentane to the total mass of the pentane foaming agent is ≥ 65wt%. Similarly, when the butane foaming agent is selected from a combination of n-butane and isobutane, for example, when the isobutane content in the composition is ≥ 20 wt% (the specific value can be selected with reference to the numerical values ​​cited above), the proportion of the isobutane is calculated based on the total mass of isobutane to the total mass of the butane foaming agent. Furthermore, when the butane foaming agent is selected from a combination of n-butane and isobutane, and the butane foaming agent is added to both the white material and the black material, the composition of the butane foaming agent added to the white material or the black material alone may not be limited by the aforementioned isobutane composition range, and ultimately the total mass of isobutane to the total mass of the butane foaming agent meets the requirement.

[0087] According to some embodiments of the present invention, before the reaction, the temperature of the black material and the white material is independently 10 to 30° C., for example, 10° C., 15° C., 20° C., 25° C., 30° C. or any value therebetween. The temperature range is controlled to reduce the loss of the foaming agent while ensuring the reaction activity.

[0088] It is understood that the temperature of the white material and the black material can be the same or different. In addition, the black material and the white material are kept constant near the reaction temperature in advance and then mixed to improve production efficiency.

[0089] According to some embodiments of the present invention, the mixing gun head pressure is 100-150 bar, for example, it can be 100 bar, 110 bar, 120 bar, 130 bar, 140 bar, 150 bar or any value therebetween. Generally, the greater the gun head pressure, the smaller the particle size of the black material and the white material after atomization, and the better the mixing effect. However, excessive gun head pressure (such as exceeding 150 bar) may affect the long-term service life of the high-pressure foaming machine and increase the operation and maintenance costs of the production line.

[0090] A third aspect of the present invention relates to the use of the rigid polyurethane foam material in household appliances.

[0091] In view of the advantages of the above-mentioned rigid polyurethane foam materials, while ensuring the quality, production efficiency and environmental protection of the foamed products, it has a lower production cost and can better meet the application requirements of household appliances such as refrigerators / freezers.

[0092] According to some embodiments of the present invention, the household appliance includes a refrigerator, a freezer, a water heater, an air conditioner or a heat pump.

[0093] Herein, "plurality" includes two or more than two; when referring to a numerical range, the term "plurality" includes both the end values ​​and any subset range within the range.

[0094] "Polyisocyanate" refers to any isocyanate compound containing at least two isocyanate groups in a single molecule that can be used to produce polyurethane foam.

[0095] “Mixing the raw materials for preparing…” includes both mixing all the raw materials in one step and mixing in steps. For example, “mixing the raw materials for preparing the rigid polyurethane foam material” includes mixing in one step or mixing in steps. Among them, step-by-step mixing is more suitable for actual foaming production line applications. Usually, some components including polyols are premixed (for example, the white material includes polyols, surfactants, catalysts, etc., and may also include physical foaming agents such as pentane and butane and / or water) to form a white material; the remaining components including polyisocyanates are premixed (for example, the black material may also include a physical foaming agent, etc.) to form a black material; and then the white material and the black material are mixed for foaming. When a volatile physical foaming agent (such as a pentane or butane foaming agent) is added to the white material, the raw material supplier can complete the premixing of the components other than the physical foaming agent, and then further mix these physical foaming agents into the foaming production line at the application end to prepare the white material. This method can improve the foaming efficiency of the foaming production line and reduce equipment investment. It should be understood that step-by-step mixing can be mixing in two or more steps. Taking white material as an example, in some cases, splitting the raw materials for preparing the white material other than the physical foaming agent into two or more parts and premixing them separately before mixing them with the physical foaming agent may be beneficial to improving the foam performance.

[0096] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0097] Figure 1 It is a schematic diagram of the thermal conductivity mechanism of foam materials.

[0098] Figure 2 It is a schematic diagram of the polyurethane foaming process. DETAILED DESCRIPTION

[0099] Embodiments of the present invention are described in detail below. The embodiments are exemplary and are only used to explain the present invention, but should not be construed as limiting the present invention.

[0100] This embodiment provides a rigid polyurethane foam, and the raw materials for preparation include: by mass, 100 parts of polyol, 2-6 parts of surfactant, 2-6 parts of catalyst, 2.2-3.5 parts of water, 14-20 parts of pentane foaming agent, 1.8-4 parts of butane foaming agent, and 140-170 parts of polyisocyanate. By using a high proportion of water as a chemical foaming agent and using pentane and butane physical foaming agents as halogen-free foaming agents, the purposes of low foam core density, low thermal conductivity, rapid demoulding of products, etc. are achieved, and the foam strength can be guaranteed.

[0101] The thermal conductivity of polyurethane foam is mainly determined by the solid phase thermal conductivity brought by the matrix and the gas phase thermal conductivity brought by the foaming agent gas. The thermal conductivity of the foam can be effectively reduced by reducing the foam density and the cell size to reduce the solid phase thermal conductivity of the foam, and combining it with the use of a foaming agent with a low thermal conductivity coefficient (such as a halogen-containing foaming agent) to reduce the gas phase thermal conductivity of the foam. Among them, reducing the solid phase thermal conductivity is mainly achieved by reducing the foam density and the cell size. Figure 1 Schematic diagram of heat conduction mechanism (circles in the figure represent pores, and lines with arrows indicate heat transfer paths). The smaller the pore size of the foam and the lower the foam density (i.e., small and dense pores), the longer the heat transfer path in the solid part, the slower the heat transfer, and the relatively small solid phase thermal conductivity. Improving the demoulding speed is mainly achieved by reducing the total foam filling amount by reducing the density of the filled foam core, thereby reducing the amount of demoulding deformation, so as to improve production efficiency.

[0102] Existing polyurethane foams with low thermal conductivity, fast demoulding and low density mainly use pentane foaming agents (such as cyclopentane, n-pentane and isopentane), and are used in combination with some halogen-containing foaming agents with low boiling point and low thermal conductivity to meet the requirements of fast demoulding, high-efficiency thermal insulation and low foam core density. Refer to Table 1 for the performance parameters of commonly used halogen-containing and halogen-free foaming agents. It can be seen that compared with commonly used halogen-containing foaming agents, halogen-free foaming agents have higher thermal conductivity or higher boiling point. Therefore, it is difficult to ensure low gas phase thermal conductivity by using halogen-free foaming agents, or the high boiling point of the foaming agent affects the internal pressure of the foam cells, making it difficult to ensure foam strength at the same foam density.

[0103] Table 1 Performance parameters of commonly used halogen-containing / halogen-free foaming agents

[0104]

[0105]

[0106] Due to concerns about climate and environmental changes, the European Union issued a directive on the control of fluorinated greenhouse gases (OJL 2024 / 573) on February 20, 2024. According to the relevant provisions of OJL 2024 / 573, LBA, HFC-152a, GBA, FEA-1150, HFC-134a and other fluorinated low-boiling point, low thermal conductivity blowing agents will be banned from use in refrigerators / freezers produced / sold in the EU from January 1, 2026. The existing halogen-free alternative blowing agents are mainly pentane physical blowing agents combined with water as a chemical blowing agent. Due to the high boiling point of pentane, the gas pressure in the pores is relatively low. If the foam core density is low, it is very easy to cause foam shrinkage, deformation and other problems during use. Therefore, the foam core density based on the above foaming system is often 32kg / m 3 The demoulding time is more than 240s, the thermal conductivity is more than 19.5mW / m·K, the foam has high density, high cost, low production efficiency, and poor insulation performance, which makes it difficult to meet the requirements of high efficiency energy saving, cost and efficiency.

[0107] The cell growth of polyurethane foam is a complex process, and the final shape of the cell is closely related to the control of the cell growth process. Figure 2, is a schematic diagram of the polyurethane foaming process (the circles in the figure represent the pores, and P1>P3>P2 represent the size of the bubble merging tendency, that is, P1 and P3 are more inclined to merge with P2). During the polymerization reaction of polyurethane, the foaming reaction produces carbon dioxide. In addition, a small amount of air dissolved in the polyol and the added physical foaming agent will undergo an initial phase transition. Thermodynamic instability often occurs during the phase transition, which becomes the driving force for inducing nucleation and produces original bubble nuclei in the reaction system. As the reaction proceeds further, the temperature of the system continues to rise, and more foaming agent gas will gather and fill in the original bubble nucleus, and the size of the bubble will gradually increase. During the growth of the bubble, due to factors such as pressure imbalance, the merging and collapse of the bubble will further occur. Since the newly generated gas phase is preferentially filled in the original bubble nucleus during the growth of the bubble, the more the original bubble nucleus, the more the total number of bubbles will be in the end, and the smaller the size of the bubble will be at the same density.

[0108] Previous studies have promoted the nucleation of bubbles by using nucleating agents. Nucleating agents are divided into particles and low surface energy liquids. Since the viscosity of polyurethane white material is generally high, it is difficult to disperse particle-type nucleating agents in the white material more evenly, and there are still many challenges in practical applications; low surface energy liquids, such as perfluorohexene, have poor compatibility in white materials, and the amount of addition is also strictly limited. In addition, the above substances are also on the restricted use list of the EU ban.

[0109] This solution uses a high-quality portion of water, which can obtain a more delicate pore structure (which may indicate that water has a better bubble nucleation effect), and can then compensate for the high gas phase thermal conductivity caused by the use of halogen-free foaming agents by reducing solid phase thermal conductivity, thereby obtaining foam performance equivalent to that of halogen-containing foaming agents (low density, low thermal conductivity, fast demoulding, etc.). The carbon dioxide produced by the reaction of water and isocyanate has a low boiling point and a high saturated vapor pressure, which is conducive to increasing the internal pressure of the pores and effectively enhancing the compressive strength of the foam at a lower foam core density.

[0110] Butane foaming agents have a low boiling point and can provide a greater internal pressure for the pores, which is beneficial to improving the overall strength of the foam by increasing the vapor pressure in the pores at a lower foam core density. Pentane foaming agents have a low gas phase thermal conductivity, which is beneficial to improving the thermal conductivity of the foam, but the boiling point of pentane foaming agents is relatively high. By adjusting the foaming agent ratio (the ratio of pentane, butane and water, where pentane and butane substances can form azeotropes to improve foam strength, and more carbon dioxide produced by the reaction of water and isocyanate can also improve foam strength), the role of pentane foaming agents in improving thermal conductivity and the role of butane foaming agents and water in improving foam strength are fully utilized, and finally a foam with a lower core density (29.5kg / m 3Below, further down to 28.5kg / m 3 The foam product has the advantages of low thermal conductivity (below 19.3mW / m·K, and further reduced to about 18.8mW / m·K), fast demoulding rate (120-180s) and high compressive strength (≥120kPa), and has both cost and environmental protection advantages.

[0111] From the perspective of gas phase thermal conductivity alone, the gas phase thermal conductivity of the foaming agent of this scheme is higher than that of the halogen-containing foaming agent with low boiling point and low thermal conductivity (such as LBA), but the reduction in pore size reduces the solid phase thermal conductivity, and ultimately the comprehensive thermal conductivity of the foam can also be maintained at a favorable level.

[0112] Surfactants are used to improve the mixing uniformity of components and enhance the uniformity of foaming. Properly controlling the amount of surfactant can stabilize the foam, help give full play to the role of the foaming agent, and form a uniform and fine cell structure.

[0113] Butane foaming agents have a small molecular weight and low unit price, and the water content is increased, which effectively reduces the cost of foaming materials. In addition, this solution does not use halogen-containing foaming agents, is environmentally friendly, has low ODP and GWP values, is not subject to EU regulations, and can well meet the application requirements of domestic and foreign markets, especially conducive to expanding overseas markets.

[0114] The following is a detailed description through specific examples. In the following examples, the relevant raw materials are described as follows:

[0115] Polyols: polyether polyol NJ-8238 (hydroxyl value 380±15mgKOH / g, functionality 5-6) with sucrose as initiator, 35 parts by mass; polyether polyol TD405 (hydroxyl value 397.5±17.5mgKOH / g, functionality 4) with toluene diamine as initiator, 35 parts by mass; polyether polyol NJ-6045 (hydroxyl value 450±15mgKOH / g, functionality 5-6) with sorbitol as initiator, 20 parts by mass; polyether polyol NJ-305 (hydroxyl value 385±15mgKOH / g, functionality 3) with glycerol as initiator, 5 parts by mass; polyester polyol PS-3152 (hydroxyl value 315±15mgKOH / g, functionality 2), 5 parts by mass; average functionality is about 4.7, and average hydroxyl value is about 398mgKOH / g.

[0116] Surfactant: Evonik Chemicals B-84813.

[0117] Butane foaming agent: n-butane R-600, isobutane R-600a.

[0118] Polyisocyanate: Wanhua PM-200.

[0119] The relevant test methods are as follows:

[0120] 1. Core density: Take samples of peeled foam in the following size: (50±1)mm×(50±1)mm×(50±1)mm, and measure the density by the water displacement method. The number of samples is 3, and the results are averaged.

[0121] 2. Thermal conductivity: Use a cutting machine to cut the foamed sample into (200±5)mm×(200±5)mm, (25±1)mm thick peeled foam. The cold plate temperature of the thermal conductivity meter is 2℃ and the hot plate temperature is 18℃. Considering the temperature fluctuation, the temperature difference between the hot and cold plates does not exceed 18℃. The average temperature is 10℃. Take 2 samples and take the average value of the results.

[0122] 3. Average cell size of free bubbles: Scanning electron microscope (SEM) observation was used to count the sizes of all cells in the SEM photos with a magnification of 100× to obtain the average cell size of free bubbles.

[0123] 4. Number of air pit defects on the surface: Disassemble the refrigerator liner after foaming and count the number of air pit defects on the outer surface of the foam part with a diameter > 3cm.

[0124] 5. Compression strength: The test is based on GB / T 26689-2011 "Rigid polyurethane foam for refrigerators and freezers", the sample size is (50±1) mm×(50±1) mm×(30±1) mm, the test speed is (5±1) mm / min, and the load is applied to the three directions (length / width / height) of the sample. The number of samples in each direction is 3, and the average value of the 3 test data in each direction is taken. The result is the minimum value of the 3 average values. The current national standard for the compression strength of polyurethane rigid foam for refrigerators / freezers requires ≥120kPa.

[0125] Example 1-1

[0126] A rigid polyurethane foam material is prepared, comprising:

[0127] The white material and the black material are mixed by the high-pressure foaming machine gun head and filled into the mold for curing. The black material temperature is 20°C, the white material temperature is 20°C, the gun head pressure is 130 bar, and the black and white material ratio is 1.35.

[0128] Among them, the white material includes the following components: polyol, 100 parts by mass; surfactant, 5 parts by mass; catalyst, 3.4 parts by mass (0.3 parts by mass of pentamethyldiethylenetriamine, 2.6 parts by mass of N,N-dimethylcyclohexylamine, 0.5 parts by mass of tris(dimethylaminopropyl)hexahydrotriazine); water, 2.5 parts by mass; cyclopentane, 13 parts by mass.

[0129] The black material includes the following components: polymerized MDI, PM-200, 160 parts by mass; cyclopentane, 4 parts by mass; butane foaming agent (the mass ratio of R-600 to R-600a is 1:1), 3.2 parts by mass.

[0130] Example 1-2

[0131] A rigid polyurethane foam material is prepared, comprising:

[0132] The white material and the black material are mixed by the high-pressure foaming machine gun head and filled into the mold for curing. Among them, the temperature of the black material is 20℃, the temperature of the white material is 20℃; the gun head pressure is 130bar; the black and white material ratio is 1.34.

[0133] Among them, the white material includes the following components: polyol, 100 parts by mass; surfactant, 5 parts by mass; catalyst, 3.2 parts by mass (0.3 parts by mass of pentamethyldiethylenetriamine, 2.4 parts by mass of N,N-dimethylcyclohexylamine, 0.5 parts by mass of tris(dimethylaminopropyl)hexahydrotriazine); water, 2.7 parts by mass; cyclopentane, 13 parts by mass.

[0134] The black material includes the following components: polymerized MDI, PM-200, 160 parts by mass; cyclopentane, 3.5 parts by mass; butane (the mass ratio of R-600 to R-600a is 1:1), 3 parts by mass.

[0135] Examples 1-3

[0136] A rigid polyurethane foam material is prepared, comprising:

[0137] The white material and the black material are mixed by the high-pressure foaming machine gun head and filled into the mold for curing. Among them, the temperature of the black material is 20℃, the temperature of the white material is 20℃; the gun head pressure is 130bar; the black and white material ratio is 1.34.

[0138] Among them, the white material includes the following components: polyol, 100 parts by mass; surfactant, 5 parts by mass; catalyst, 3 parts by mass (0.3 parts by mass of pentamethyldiethylenetriamine, 2.2 parts by mass of N,N-dimethylcyclohexylamine, 0.5 parts by mass of tris(dimethylaminopropyl)hexahydrotriazine); water, 2.9 parts by mass; cyclopentane, 13 parts by mass.

[0139] The black material includes the following components: polymerized MDI, PM-200, 160 parts by mass; cyclopentane, 3 parts by mass; butane (the mass ratio of R-600 to R-600a is 1:1), 2.7 parts by mass.

[0140] Examples 1-4

[0141] A rigid polyurethane foam material is prepared, comprising:

[0142] The white material and the black material are mixed by the gun head of the high-pressure foaming machine and filled into the mold for curing. Among them, the temperature of the black material is 20℃, the temperature of the white material is 20℃; the gun head pressure is 130bar; the black and white material ratio is 1.36.

[0143] The white material includes the following components: polyol, 100 parts by mass; surfactant, 5 parts by mass; catalyst, 3.6 parts by mass (0.4 parts by mass of pentamethyldiethylenetriamine, 2.6 parts by mass of N,N-dimethylcyclohexylamine, 0.6 parts by mass of tris(dimethylaminopropyl)hexahydrotriazine); water, 2.2 parts by mass; cyclopentane, 13 parts by mass.

[0144] The black material includes the following components: polymerized MDI, PM-200, 160 parts by mass; cyclopentane, 5 parts by mass; butane (the mass ratio of R-600 to R-600a is 1:1), 3.4 parts by mass.

[0145] Comparative Example 1-1

[0146] A rigid polyurethane foam material is prepared, comprising:

[0147] The white material and the black material are mixed by the high-pressure foaming machine gun head and filled into the mold for curing. Among them, the temperature of the black material is 20℃, the temperature of the white material is 20℃; the gun head pressure is 130bar; the black and white material ratio is 1.37.

[0148] Among them, the white material includes the following components: polyol, 100 parts by mass; surfactant, 5 parts by mass; catalyst, 3.8 parts by mass (0.4 parts by mass of pentamethyldiethylenetriamine, 2.8 parts by mass of N,N-dimethylcyclohexylamine, 0.6 parts by mass of tris(dimethylaminopropyl)hexahydrotriazine); water, 2 parts by mass; cyclopentane, 13 parts by mass.

[0149] The black material includes the following components: polymerized MDI, PM-200, 160 parts by mass; cyclopentane, 5.5 parts by mass; butane (the mass ratio of R-600 to R-600a is 1:1), 3.5 parts by mass.

[0150] Some process parameters and performances of Examples 1-1 to 1-4 and Comparative Example 1-1 are shown in Table 2.

[0151] Table 2 Parameter comparison of Examples 1-1 to 1-4 and Comparative Example 1-1

[0152]

[0153] Combining the above-mentioned examples with the comparative data, it can be seen that increasing the amount of chemical foaming agent water added will reduce the size of the free bubble holes accordingly (the total molar number of the physical foaming agent and the chemical foaming agent is not much different, and the foam density is not much different (considering the foam density distribution and the normal test error of ±0.2kg / m 3). Although the chemical foaming agent has a low water content and the corresponding gas phase thermal conductivity is lower, the low water content leads to poor nucleation effect, the foam cell size is correspondingly larger, the solid phase thermal conductivity is correspondingly higher, and the corresponding foam thermal conductivity is higher. The cell size of conventional polyurethane foam is generally above 200μm. The use of a higher proportion of water in this solution may produce an excellent nucleation effect, so that the cell size can even be reduced to below 200μm. At a comparable foam density, the solid phase thermal conductivity of the foam is reduced by reducing the cell size.

[0154] Example 2-1

[0155] A rigid polyurethane foam material is prepared, comprising:

[0156] The white material and the black material are mixed by the high-pressure foaming machine gun head and filled into the mold for curing. Among them, the temperature of the black material is 20℃, the temperature of the white material is 20℃; the gun head pressure is 130bar; the black and white material ratio is 1.43.

[0157] The white material includes the following components: polyol, 100 parts by mass; surfactant, 5 parts by mass; catalyst, 3.4 parts by mass (0.3 parts by mass of pentamethyldiethylenetriamine, 2.6 parts by mass of N,N-dimethylcyclohexylamine, 0.5 parts by mass of tris(dimethylaminopropyl)hexahydrotriazine); water, 2.55 parts by mass; cyclopentane, 9 parts by mass.

[0158] The black material includes the following components: polymerized MDI, PM-200, 160 parts by mass; cyclopentane, 8 parts by mass; butane (the mass ratio of R-600 to R-600a is 1:1), 3.1 parts by mass.

[0159] Example 2-2

[0160] A rigid polyurethane foam material is prepared, comprising:

[0161] The white material and the black material are mixed by the high-pressure foaming machine gun head and filled into the mold for curing. Among them, the temperature of the black material is 20℃, the temperature of the white material is 20℃; the gun head pressure is 130bar; the black and white material ratio is 1.39.

[0162] Among them, the white material includes the following components: polyol, 100 parts by mass; surfactant, 5 parts by mass; catalyst, 3.4 parts by mass (0.3 parts by mass of pentamethyldiethylenetriamine, 2.6 parts by mass of N,N-dimethylcyclohexylamine, 0.5 parts by mass of tris(dimethylaminopropyl)hexahydrotriazine); water, 2.55 parts by mass; cyclopentane, 11 parts by mass.

[0163] The black material includes the following components: polymerized MDI, PM-200, 160 parts by mass; cyclopentane, 6 parts by mass; butane (the mass ratio of R-600 to R-600a is 1:1), 3.1 parts by mass.

[0164] Example 2-3

[0165] A rigid polyurethane foam material is prepared, comprising:

[0166] The white material and the black material are mixed by the high-pressure foaming machine gun head and filled into the mold for curing. The black material temperature is 20°C, the white material temperature is 20°C, the gun head pressure is 130 bar, and the black and white material ratio is 1.35.

[0167] Among them, the white material includes the following components: polyol, 100 parts by mass; surfactant, 5 parts by mass; catalyst, 3.4 parts by mass (0.3 parts by mass of pentamethyldiethylenetriamine, 2.6 parts by mass of N,N-dimethylcyclohexylamine, 0.5 parts by mass of tris(dimethylaminopropyl)hexahydrotriazine); water, 2.55 parts by mass; cyclopentane, 13 parts by mass.

[0168] The black material includes the following components: polymerized MDI, PM-200, 160 parts by mass; cyclopentane, 4 parts by mass; butane (the mass ratio of R-600 to R-600a is 1:1), 3.1 parts by mass.

[0169] Embodiment 2-4

[0170] A rigid polyurethane foam material is prepared, comprising:

[0171] The white material and the black material are mixed by the high-pressure foaming machine gun head and filled into the mold for curing. Among them, the temperature of the black material is 20℃, the temperature of the white material is 20℃; the gun head pressure is 130bar; the black and white material ratio is 1.31.

[0172] Among them, the white material includes the following components: polyol, 100 parts by mass; surfactant, 5 parts by mass; catalyst, 3.4 parts by mass (0.3 parts by mass of pentamethyldiethylenetriamine, 2.6 parts by mass of N,N-dimethylcyclohexylamine, 0.5 parts by mass of tris(dimethylaminopropyl)hexahydrotriazine); water, 2.55 parts by mass; cyclopentane, 15 parts by mass.

[0173] The black material includes the following components: polymerized MDI, PM-200, 160 parts by mass; cyclopentane, 2 parts by mass; butane (the mass ratio of R-600 to R-600a is 1:1), 3.1 parts by mass.

[0174] Embodiment 2-5

[0175] A rigid polyurethane foam material is prepared, comprising:

[0176] The white material and the black material are mixed by the high-pressure foaming machine gun head and filled into the mold for curing. The black material temperature is 20°C, the white material temperature is 20°C, the gun head pressure is 130 bar, and the black and white material ratio is 1.27.

[0177] The white material includes the following components: polyol, 100 parts by mass; surfactant, 5 parts by mass; catalyst, 3.4 parts by mass (0.3 parts by mass of pentamethyldiethylenetriamine, 2.6 parts by mass of N,N-dimethylcyclohexylamine, 0.5 parts by mass of tris(dimethylaminopropyl)hexahydrotriazine); water, 2.55 parts by mass; cyclopentane, 17 parts by mass.

[0178] The black material includes the following components: polymerized MDI, PM-200, 160 parts by mass; butane (the mass ratio of R-600 to R-600a is 1:1), 3.1 parts by mass.

[0179] Some process parameters and performances of Examples 2-1 to 2-5 are shown in Table 3.

[0180] Table 3 Parameter comparison of Examples 2-1 to 2-5

[0181]

[0182]

[0183] It can be seen from the above-mentioned embodiment data that the distribution ratio of pentane in black and white materials has an impact on the surface quality and thermal conductivity of foam. Controlling the pentane foaming agent in white material to be more than 7 mass parts (per 100 mass parts of polyols), the viscosity of white material can be reduced, which is more conducive to the mixing of black and white materials, while reducing the impact on conveying equipment (such as booster pump), which is convenient for the transportation of white material. Along with the lifting of the pentane foaming agent number in white material, the concentration of the catalyst can be diluted accordingly, and the reaction activity will have a certain reduction when the black and white materials are mixed, and the reaction slows down, and the cell size can be increased to a certain extent, so that the thermal conductivity of foam is slightly increased. In addition, the pentane foaming agent has limited compatibility with the polyols in white material, such as the pentane foaming agent number in white material is too much, and the foaming agent is quickly separated out during foaming so that the gas pit defect on the foam surface is increased.

[0184] Butane foaming agents have a low boiling point and escape quickly under heat drive during foaming. Adding pentane to the black material can increase the compatibility of butane foaming agents and form an azeotropic agent to slow down the escape rate of butane gases. The gas pit defects will also be reduced accordingly during foaming.

[0185] Example 3-1

[0186] A rigid polyurethane foam material is prepared, comprising:

[0187] The white material and the black material are mixed by the high-pressure foaming machine gun head and filled into the mold for curing. The black material temperature is 20°C, the white material temperature is 20°C, the gun head pressure is 130 bar, and the black and white material ratio is 1.35.

[0188] Among them, the white material includes the following components: polyol, 100 parts by mass; surfactant, 5 parts by mass; catalyst, 3.4 parts by mass (0.3 parts by mass of pentamethyldiethylenetriamine, 2.6 parts by mass of N,N-dimethylcyclohexylamine, 0.5 parts by mass of tris(dimethylaminopropyl)hexahydrotriazine); water, 2.6 parts by mass; cyclopentane, 13 parts by mass.

[0189] The black material includes the following components: polymerized MDI, PM-200, 160 parts by mass; cyclopentane, 4 parts by mass; butane (the mass ratio of R-600 to R-600a is 1:1), 3 parts by mass.

[0190] Example 3-2

[0191] A rigid polyurethane foam material is prepared, comprising:

[0192] The white material and the black material are mixed by the high-pressure foaming machine gun head and filled into the mold for curing. The black material temperature is 20°C, the white material temperature is 20°C, the gun head pressure is 130 bar, and the black and white material ratio is 1.35.

[0193] Among them, the white material includes the following components: polyol, 100 parts by mass; surfactant, 5 parts by mass; catalyst, 3.4 parts by mass (0.3 parts by mass of pentamethyldiethylenetriamine, 2.6 parts by mass of N,N-dimethylcyclohexylamine, 0.5 parts by mass of tris(dimethylaminopropyl)hexahydrotriazine); water, 2.6 parts by mass; cyclopentane, 13 parts by mass.

[0194] The black material includes the following components: polymeric MDI, PM-200, 160 parts by mass; a mixture of cyclopentane and isopentane (15 wt % isopentane), 4 parts by mass; and butane (R-600 and R-600a have a mass ratio of 1:1), 3 parts by mass.

[0195] Example 3-3

[0196] A rigid polyurethane foam material is prepared, comprising:

[0197] The white material and the black material are mixed by the high-pressure foaming machine gun head and filled into the mold for curing. The black material temperature is 20°C, the white material temperature is 20°C, the gun head pressure is 130 bar, and the black and white material ratio is 1.35.

[0198] Among them, the white material includes the following components: polyol, 100 parts by mass; surfactant, 5 parts by mass; catalyst, 3.4 parts by mass (0.3 parts by mass of pentamethyldiethylenetriamine, 2.6 parts by mass of N,N-dimethylcyclohexylamine, 0.5 parts by mass of tris(dimethylaminopropyl)hexahydrotriazine); water, 2.6 parts by mass; 13 parts by mass of a mixture of cyclopentane and isopentane (15wt% of isopentane).

[0199] The black material includes the following components: polymeric MDI, PM-200, 160 parts by mass; a mixture of cyclopentane and isopentane (15 wt % isopentane), 4 parts by mass; and butane (R-600 and R-600a have a mass ratio of 1:1), 3 parts by mass.

[0200] Embodiment 3-4

[0201] A rigid polyurethane foam material is prepared, comprising:

[0202] The white material and the black material are mixed by the high-pressure foaming machine gun head and filled into the mold for curing. The black material temperature is 20°C, the white material temperature is 20°C, the gun head pressure is 130 bar, and the black and white material ratio is 1.35.

[0203] Among them, the white material includes the following components: polyol, 100 parts by mass; surfactant, 5 parts by mass; catalyst, 3.4 parts by mass (0.3 parts by mass of pentamethyldiethylenetriamine, 2.6 parts by mass of N,N-dimethylcyclohexylamine, 0.5 parts by mass of tris(dimethylaminopropyl)hexahydrotriazine); water, 2.6 parts by mass; 13 parts by mass of a mixture of cyclopentane and isopentane (30wt% of isopentane).

[0204] The black material includes the following components: polymeric MDI, PM-200, 160 parts by mass; a mixture of cyclopentane and isopentane (30 wt% isopentane), 4 parts by mass; and butane (the mass ratio of R-600 to R-600a is 1:1), 3 parts by mass.

[0205] Embodiment 3-5

[0206] A rigid polyurethane foam material is prepared, comprising:

[0207] The white material and the black material are mixed by the high-pressure foaming machine gun head and filled into the mold for curing. The black material temperature is 20°C, the white material temperature is 20°C, the gun head pressure is 130 bar, and the black and white material ratio is 1.35.

[0208] Among them, the white material includes the following components: polyol, 100 parts by mass; surfactant, 5 parts by mass; catalyst, 3.4 parts by mass (0.3 parts by mass of pentamethyldiethylenetriamine, 2.6 parts by mass of N,N-dimethylcyclohexylamine, 0.5 parts by mass of tris(dimethylaminopropyl)hexahydrotriazine); water, 2.6 parts by mass; 13 parts by mass of a mixture of cyclopentane and isopentane (15wt% of isopentane).

[0209] The black material includes the following components: polymerized MDI, PM-200, 160 parts by mass; cyclopentane, 4 parts by mass; butane (the mass ratio of R-600 to R-600a is 1:1), 3 parts by mass.

[0210] Embodiment 3-6

[0211] A rigid polyurethane foam material is prepared, comprising:

[0212] The white material and the black material are mixed by the high-pressure foaming machine gun head and filled into the mold for curing. The black material temperature is 20°C, the white material temperature is 20°C, the gun head pressure is 130 bar, and the black and white material ratio is 1.35.

[0213] Among them, the white material includes the following components: polyol, 100 parts by mass; surfactant, 5 parts by mass; catalyst, 3.4 parts by mass (0.3 parts by mass of pentamethyldiethylenetriamine, 2.6 parts by mass of N,N-dimethylcyclohexylamine, 0.5 parts by mass of tris(dimethylaminopropyl)hexahydrotriazine); water, 2.6 parts by mass; cyclopentane, 13 parts by mass.

[0214] The black material includes the following components: polymeric MDI, PM-200, 160 parts by mass; cyclopentane, 4 parts by mass; and butane (R-600), 3 parts by mass.

[0215] Embodiment 3-7

[0216] A rigid polyurethane foam material is prepared, comprising:

[0217] The white material and the black material are mixed by the high-pressure foaming machine gun head and filled into the mold for curing. The black material temperature is 20°C, the white material temperature is 20°C, the gun head pressure is 130 bar, and the black and white material ratio is 1.35.

[0218] Among them, the white material includes the following components: polyol, 100 parts by mass; surfactant, 5 parts by mass; catalyst, 3.4 parts by mass (0.3 parts by mass of pentamethyldiethylenetriamine, 2.6 parts by mass of N,N-dimethylcyclohexylamine, 0.5 parts by mass of tris(dimethylaminopropyl)hexahydrotriazine); water, 2.6 parts by mass; cyclopentane, 13 parts by mass.

[0219] The black material includes the following components: polymeric MDI, PM-200, 160 parts by mass; cyclopentane, 4 parts by mass; butane (R-600a), 3 parts by mass.

[0220] Some process parameters and performances of Examples 3-1 to 3-7 are shown in Table 4.

[0221] Table 4 Parameter comparison of Examples 3-1 to 3-7

[0222]

[0223]

[0224] It can be seen from the above-mentioned embodiment data that different foaming agent combinations have an impact on the thermal conductivity and compression strength of foam, and the gas phase thermal conductivity of cyclopentane is better than that of isopentane, but the boiling point of cyclopentane is higher than isopentane, therefore, using the mixture of cyclopentane and isopentane, the gas pressure in the pore is larger, and the compression strength of foam can be increased to a certain extent year-on-year. R-600 is compared with R-600a, and the boiling point of R-600 is high and the gas phase thermal conductivity is low. Only using the foam thermal conductivity of R-600 will be slightly better than using R-600 and R-600a, but the internal pressure of the pore will have a certain reduction, and in order to ensure the compression strength of foam, the foam injection amount will be appropriately increased, i.e., improve foam density. Only using the internal pressure of the pore of R-600a foam will increase, and the compression strength of foam is higher. Therefore, adopting the mixture of R-600 and R-600a is more conducive to taking into account thermal conductivity and compression strength.

[0225] Example 4-1

[0226] A rigid polyurethane foam material is prepared, comprising:

[0227] The white material and the black material are mixed by the high-pressure foaming machine gun head and filled into the mold for curing. The black material temperature is 20°C, the white material temperature is 20°C, the gun head pressure is 130 bar, and the black and white material ratio is 1.35.

[0228] Among them, the white material includes the following components: polyol, 100 parts by mass; surfactant, 5 parts by mass; catalyst, 3.4 parts by mass (0.3 parts by mass of pentamethyldiethylenetriamine, 2.6 parts by mass of N,N-dimethylcyclohexylamine, 0.5 parts by mass of tris(dimethylaminopropyl)hexahydrotriazine); water, 2.6 parts by mass; cyclopentane, 13 parts by mass.

[0229] The black material includes the following components: polymerized MDI, PM-200, 160 parts by mass; cyclopentane, 4 parts by mass; butane (the mass ratio of R-600 to R-600a is 1:1), 3 parts by mass.

[0230] Example 4-2

[0231] A rigid polyurethane foam material is prepared, comprising:

[0232] The white material and the black material are mixed by the high-pressure foaming machine gun head and filled into the mold for curing. The black material temperature is 20°C, the white material temperature is 20°C, the gun head pressure is 130 bar, and the black and white material ratio is 1.29.

[0233] Among them, the white material includes the following components: polyol, 100 parts by mass; surfactant, 5 parts by mass; catalyst, 3.4 parts by mass (0.3 parts by mass of pentamethyldiethylenetriamine, 2.6 parts by mass of N,N-dimethylcyclohexylamine, 0.5 parts by mass of tris(dimethylaminopropyl)hexahydrotriazine); water, 2.6 parts by mass; cyclopentane, 13 parts by mass; butane (the mass ratio of R-600 to R-600a is 1:1), 3 parts by mass.

[0234] The black material includes the following components: polymeric MDI, PM-200, 160 parts by mass; cyclopentane, 4 parts by mass.

[0235] Example 4-3

[0236] A rigid polyurethane foam material is prepared, comprising:

[0237] The white material and the black material are mixed by the high-pressure foaming machine gun head and filled into the mold for curing. Among them, the temperature of the black material is 20℃, the temperature of the white material is 20℃; the gun head pressure is 130bar; the black and white material ratio is 1.22.

[0238] Among them, the white material includes the following components: polyol, 100 parts by mass; surfactant, 5 parts by mass; catalyst, 3.4 parts by mass (0.3 parts by mass of pentamethyldiethylenetriamine, 2.6 parts by mass of N,N-dimethylcyclohexylamine, 0.5 parts by mass of tris(dimethylaminopropyl)hexahydrotriazine); water, 2.6 parts by mass; cyclopentane, 17 parts by mass; butane (the mass ratio of R-600 to R-600a is 1:1), 3 parts by mass.

[0239] The black material includes the following components: polymeric MDI, PM-200, 160 parts by mass.

[0240] Example 4-4

[0241] A rigid polyurethane foam material is prepared, comprising:

[0242] The white material and the black material are mixed by the high-pressure foaming machine gun head and filled into the mold for curing. The black material temperature is 20°C, the white material temperature is 20°C, the gun head pressure is 130 bar, and the black and white material ratio is 1.33.

[0243] Among them, the white material includes the following components: polyol, 100 parts by mass; surfactant, 5 parts by mass; catalyst, 3.4 parts by mass (0.3 parts by mass of pentamethyldiethylenetriamine, 2.6 parts by mass of N,N-dimethylcyclohexylamine, 0.5 parts by mass of tris(dimethylaminopropyl)hexahydrotriazine); water, 2.6 parts by mass; cyclopentane, 13 parts by mass; butane (the mass ratio of R-600 to R-600a is 1:1), 1 part by mass.

[0244] The black material includes the following components: polymerized MDI, PM-200, 160 parts by mass; cyclopentane, 4 parts by mass; butane (the mass ratio of R-600 to R-600a is 1:1), 2 parts by mass.

[0245] Embodiment 4-5

[0246] A rigid polyurethane foam material is prepared, comprising:

[0247] The white material and the black material are mixed by the high-pressure foaming machine gun head and filled into the mold for curing. Among them, the temperature of the black material is 20℃, the temperature of the white material is 20℃; the gun head pressure is 130bar; the black and white material ratio is 1.26.

[0248] Among them, the white material includes the following components: polyol, 100 parts by mass; surfactant, 5 parts by mass; catalyst, 3.4 parts by mass (0.3 parts by mass of pentamethyldiethylenetriamine, 2.6 parts by mass of N,N-dimethylcyclohexylamine, 0.5 parts by mass of tris(dimethylaminopropyl)hexahydrotriazine); water, 2.6 parts by mass; cyclopentane, 17 parts by mass; butane (the mass ratio of R-600 to R-600a is 1:1), 1 part by mass.

[0249] The black material includes the following components: polymerized MDI, PM-200, 160 parts by mass; butane (the mass ratio of R-600 to R-600a is 1:1), 2 parts by mass.

[0250] Some process parameters and performances of Examples 4-1 to 4-5 are shown in Table 5.

[0251] Table 5 Parameter comparison of Examples 4-1 to 4-5

[0252]

[0253] Combined with the above-mentioned data of the embodiment, it can be seen that adding butane foaming agent to black material and adding part of pentane foaming agent to black material is beneficial to reducing the surface defects of foam. This is because butane foaming agent has a low boiling point and is less compatible with white material than black material, so it is more suitable to be added to black material. Adding part of pentane foaming agent to black material can increase the compatibility of butane foaming agent with black material, and is also beneficial to improving the surface defects of foam.

[0254] The demoulding time of the rigid polyurethane foam materials in the above embodiments is all in the range of 120 to 180 seconds. The variation of demoulding time is mainly related to factors such as product structure design and size. For example, a large-sized refrigerator is close to 180 seconds, and a small-sized refrigerator is close to 120 seconds.

[0255] Since the rigid polyurethane foam material of this embodiment has the advantages of low core density, low thermal conductivity, rapid demoulding, etc., and can ensure the foam strength and surface quality, and has the advantages of environmental protection and low cost, it can better meet the application requirements of household appliances such as refrigerators / freezers. Among them, household appliances include refrigerators, freezers, water heaters, air conditioners or heat pumps.

[0256] The present invention has been described in detail above in conjunction with the embodiments, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge scope of ordinary technicians in the relevant technical field without departing from the purpose of the present invention.

Claims

1. A rigid polyurethane foam material, characterized in that: The preparation comprises the following raw materials in parts by mass: 100 parts of polyol, 2-6 parts of surfactant, 2-6 parts of catalyst, 2.2-3.5 parts of water, 14-20 parts of pentane foaming agent, 1.8-4 parts of butane foaming agent, and 140-170 parts of polyisocyanate.

2. The rigid polyurethane foam material according to claim 1, characterized in that: The polyol is selected from one or both of polyether polyol and polyester polyol.

3. The rigid polyurethane foam material according to claim 2, characterized in that: The polyether polyol is selected from a combination of one or more of a polyether polyol with sucrose as an initiator, a polyether polyol with sorbitol as an initiator, a polyether polyol with toluenediamine as an initiator, and a polyether polyol with glycerol as an initiator; Optionally, in the polyether polyol, the mass ratio of the polyether polyol with toluenediamine as the initiator, the polyether polyol with sucrose as the initiator, the polyether polyol with sorbitol as the initiator, and the polyether polyol with glycerol as the initiator is (20-50):(0-45):(0-30):(0-30).

4. The rigid polyurethane foam material according to claim 2, characterized in that: The polyether polyols include polyether polyols with toluenediamine as initiator, polyether polyols with sucrose as initiator, polyether polyols with sorbitol as initiator and polyether polyols with glycerol as initiator, wherein the mass ratio of the polyether polyols with toluenediamine as initiator, the polyether polyols with sucrose as initiator, the polyether polyols with sorbitol as initiator and the polyether polyols with glycerol as initiator is (4-10):(1-9):(1-6):

1.

5. The rigid polyurethane foam material according to claim 2, characterized in that: The polyester polyol is selected from phthalic anhydride polyester polyol.

6. The rigid polyurethane foam material according to any one of claims 2 to 5, characterized in that: Based on 100 parts by mass of the polyol, the polyol comprises: 80 to 100 parts of polyether polyol and 0 to 20 parts of polyester polyol; Optionally, the functionality of the polyol is 2 to 8; Optionally, the average hydroxyl value of the polyol is 300 to 500 mgKOH / g.

7. The rigid polyurethane foam material according to claim 1, characterized in that: The catalyst is selected from a combination of at least two of a foaming catalyst, a gel catalyst, and a trimerization catalyst, wherein the foaming catalyst is selected from one or two of pentamethyldiethylenetriamine and bis(dimethylaminoethyl)ether; the gel catalyst is selected from a combination of one or more of N,N-dihexylmethylamine, N,N-dimethylcyclohexylamine, triethylenediamine, dibutyltin dilaurate, and dibutyltin bis(dodecylsulfide); the trimerization catalyst is selected from a combination of one or more of tris(dimethylaminopropyl)hexahydrotriazine, 2-hydroxypropyltrimethylammonium formate, potassium acetate, and potassium isooctanoate.

8. The rigid polyurethane foam material according to claim 7, characterized in that: Based on 100 parts by mass of the polyol, the foaming catalyst is 0 to 1 part; And / or, the gel-type catalyst is 1.5 to 5 parts; And / or, the trimerization catalyst is 0.3 to 3 parts.

9. The rigid polyurethane foam material according to claim 1, characterized in that: The pentane foaming agent is selected from cyclopentane; or, the pentane foaming agent is a combination of cyclopentane and isopentane, wherein the cyclopentane is ≥ 65wt%.

10. The rigid polyurethane foam material according to claim 1, characterized in that: The butane foaming agent is selected from one or both of n-butane and isobutane; optionally, the butane foaming agent includes isobutane with a mass fraction of ≥20wt%.

11. The rigid polyurethane foam material according to claim 1, characterized in that: Based on 100 parts by mass of the polyol, the water is 2.5 to 3.5 parts; Optionally, the catalyst is 2 to 4 parts; Optionally, the pentane foaming agent is 16 to 20 parts; Optionally, the pentane foaming agent is selected from a combination of cyclopentane and isopentane, wherein the mass fraction of cyclopentane is: 70wt%≤cyclopentane≤85wt%; Optionally, the butane foaming agent includes isobutane in an amount of ≥50 wt %.

12. The rigid polyurethane foam material according to claim 1, characterized in that: In the raw materials for preparing the rigid polyurethane foam material, the molar ratio of isocyanate to active hydroxyl is (1-1.5):1, wherein the molar number of active hydroxyl is calculated as: the sum of the molar number of hydroxyl in the polyol and twice the molar number of water; and / or, the polyisocyanate is selected from polymethylene polyphenyl isocyanate.

13. The rigid polyurethane foam material according to claim 1, characterized in that: The surfactant is selected from silicone surfactants.

14. The method for preparing a rigid polyurethane foam material according to any one of claims 1 to 13, characterized in that: include: Mixing A1 part of the pentane foaming agent and B1 part of the butane foaming agent with the preparation raw materials including the polyol, the surfactant, the catalyst and the water to form a white material; Mixing the remaining A2 parts of the pentane foaming agent and the remaining B2 parts of the butane foaming agent with the preparation raw materials including the polyisocyanate to form a black material; The white material and the black material are mixed and reacted to obtain the rigid polyurethane foam material; Among them, A1, A2, B1, B2 are all ≥ 0, and satisfy: A1+A2=14~20, B1+B2=1.8~4.

15. The method for preparing a rigid polyurethane foam material according to claim 14, characterized in that: Said A1≥7.

16. The method for preparing a rigid polyurethane foam material according to claim 15, characterized in that: The A1 is 8-14.

17. The method for preparing a rigid polyurethane foam material according to any one of claims 14 to 16, characterized in that: The B2>0; optionally, the A2>0; optionally, the B1=0.

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