Polyol compositions and methods for making the same, polyurethane compositions, polyurethane foams, refrigeration equipment

Abstract

This application discloses a polyol composition and its preparation method, a polyurethane composition, a polyurethane foam, and a refrigeration device, relating to the field of polyurethane technology. The preparation method of the polyol composition includes the following steps: mixing cashew nutshell liquid, epoxide, and Lewis acid catalyst to perform an epoxy ring-opening reaction to obtain epoxidized cashew nutshell liquid; chemically modifying the oxidized cashew nutshell liquid to obtain a first cashew nutshell liquid-based polyol, a second cashew nutshell liquid-based polyol, and a third cashew nutshell liquid-based polyol; mixing one or more of the first, second, and third cashew nutshell liquid-based polyols to obtain the polyol composition. This application synthesizes three highly reactive cashew nutshell liquid-based polyols using cashew nutshell liquid as a raw material, resulting in a polyurethane foam with excellent environmental friendliness, thermal insulation, and mechanical stability.

Description

Technical Field

[0001] This application relates to the field of polyurethane technology, and in particular to a polyol composition and its preparation method, a polyurethane composition, a polyurethane foam, and a refrigeration device. Background Technology

[0002] Rigid polyurethane foam is widely used in the preparation of refrigerator insulation layers due to its excellent thermal insulation properties, lightweight and high strength. Rigid polyurethane foam is formed by mixing a polyol composition, a blowing agent, and an isocyanate component. However, the polyol compounds in the polyol composition are usually petroleum-based polyols (such as polyether polyols) and some bio-based polyols (such as vegetable oil-based and sugar-based polyols), and the blowing agent is usually a single blowing agent (such as cyclopentane). This results in rigid polyurethane foam with poor environmental friendliness, poor thermal insulation performance, and insufficient mechanical stability. Summary of the Invention

[0003] In view of this, this application provides a polyol composition and its preparation method, a polyurethane composition, a polyurethane foam, and a refrigeration device.

[0004] The embodiments of this application are implemented as follows: a method for preparing a polyol composition includes the following steps: Cashew shell liquid, epoxide and Lewis acid catalyst are mixed and subjected to an epoxy ring-opening reaction to obtain epoxidized cashew shell liquid; The epoxidized cashew shell liquid was chemically modified independently using an amination modifier, a thiol modifier, and a phosphorylation modifier to obtain a first cashew shell liquid-based polyol, a second cashew shell liquid-based polyol, and a third cashew shell liquid-based polyol, respectively. The first cashew nut shell liquid-based polyol, the second cashew nut shell liquid-based polyol, and the third cashew nut shell liquid-based polyol are mixed to obtain the polyol composition.

[0005] Optionally, in some embodiments of this application, The epoxide is selected from one or more of propylene oxide and epichlorohydrin; The Lewis acid catalyst is selected from one or more of zinc chloride, aluminum chloride, and ferrous chloride; The amount of Lewis acid catalyst added is 0.25% to 0.4% of the mass of the cashew nut shell liquid; The mass ratio of the cashew nut shell liquid to the epoxide is 1:(0.75~0.9). The epoxy ring-opening reaction is carried out at a temperature of 90℃~95℃ for 4h~6h. The epoxy value of the epoxidized cashew shell liquid is 0.32 mol / 100g to 0.45 mol / 100g.

[0006] Optionally, in some embodiments of this application, the epoxidized cashew shell liquid includes a first epoxidized cashew shell liquid for preparing the first cashew shell liquid-based polyol, a second epoxidized cashew shell liquid for preparing the second cashew shell liquid-based polyol, and a third epoxidized cashew shell liquid for preparing the third cashew shell liquid-based polyol. The first epoxidized cashew shell liquid has an epoxy value of 0.32 mol / 100g to 0.36 mol / 100g, the second epoxidized cashew shell liquid has an epoxy value of 0.37 mol / 100g to 0.40 mol / 100g, and the third epoxidized cashew shell liquid has an epoxy value of 0.41 mol / 100g to 0.45 mol / 100g.

[0007] Optionally, in some embodiments of this application, the chemical modification of the epoxidized cashew shell liquid using an amination modifier, a thiol modifier, and a phosphorylation modifier, respectively, to obtain a first cashew shell liquid-based polyol, a second cashew shell liquid-based polyol, and a third cashew shell liquid-based polyol, includes: The amination modifier and the first epoxidized cashew shell liquid are mixed and subjected to a first microwave heating treatment to obtain the first cashew shell liquid-based polyol. Under nitrogen atmosphere and ultraviolet light irradiation, the second epoxidized cashew shell liquid, the thiol modifier and the photoinitiator are mixed and subjected to a second microwave heating treatment to obtain the second cashew shell liquid-based polyol. The phosphorylation modifier and the third epoxidized cashew shell liquid are mixed and heated to obtain the third cashew shell liquid-based polyol.

[0008] Optionally, in some embodiments of this application, The molar ratio of the first epoxidized cashew shell liquid to the amination modifier is 1:(1.15~1.25). The molar ratio of the second epoxidized cashew nut shell liquid, the thiol modifier, and the photoinitiator is 1:(1.8~2.0):(0.005~0.007). The molar ratio of the third epoxidized cashew nut shell liquid to the phosphorylation modifier is 1:(1.15~1.25). The amination modifier is selected from one or more of glycine, diethanolamine, triethanolamine, isopropanolamine, tetraethylenepentamine, and triethylenetetramine; The thiol modifier is selected from one or more of 2-mercaptoethanol, 3-mercaptopropane-1,2-diol, and propane-1-thiol; The photoinitiator is selected from one or more of 2,2-dimethoxy-2-phenylacetophenone, 2,2-dialkyl-2-hydroxyacetophenone, 2-hydroxy-2-methyl-phenylacetophenone, phenylbis-(2,4,6-trimethylbenzoyl)-phosphine oxide, benzophenone, and 2-isopropylthioxanthone; The phosphorylation modifier is selected from phosphoric acid; The microwave power of the first microwave heating treatment is 280W~320W, the temperature is 115℃~125℃, and the time is 2h~2.5h; The wavelength of the ultraviolet light is 365nm~400nm; the microwave power of the second microwave heating treatment is 280W~320W, the temperature is 60℃~65℃, and the time is 24h~30h; The heat treatment is performed at a temperature of 80℃~85℃ for a duration of 6h~6.5h.

[0009] Optionally, in some embodiments of this application, The first cashew nutshell liquid-based polyol has a hydroxyl value of 345 mgKOH / g to 355 mgKOH / g, the second cashew nutshell liquid-based polyol has a hydroxyl value of 395 mgKOH / g to 405 mgKOH / g, and the third cashew nutshell liquid-based polyol has a hydroxyl value of 415 mgKOH / g to 425 mgKOH / g; and / or The first cashew nutshell liquid-based polyol has an acid value ≤ 0.08 mgKOH / g, the second cashew nutshell liquid-based polyol has an acid value ≤ 0.08 mgKOH / g, and the third cashew nutshell liquid-based polyol has an acid value ≤ 0.09 mgKOH / g; and / or The viscosities of the first cashew shell liquid-based polyol, the second cashew shell liquid-based polyol, and the third cashew shell liquid-based polyol at 25°C are each independently selected from 15 Pa·s to 30 Pa·s.

[0010] Optionally, in some embodiments of this application, the cashew nut shell liquid is further subjected to pretreatment before reacting with the epoxide. The pretreatment includes: sequentially subjecting the cashew nut shell liquid to vacuum dehydration and filtration; wherein... The moisture content of the pretreated cashew shell liquid is ≤0.3%; The cashew nut shell liquid has a cashew phenol content of ≥70%, an acid value of 10 mgKOH / g~15 mgKOH / g, and a moisture content of ≤0.5%. The vacuum degree of the vacuum dehydration process is -0.09 MPa to -0.095 MPa, the temperature is 115 ℃ to 125 ℃, and the time is 2 h to 2.5 h.

[0011] Optionally, in some embodiments of this application, after the epoxidized cashew shell liquid is chemically modified by independently employing an amination modifier, a thiol modifier, and a phosphorylation modifier to obtain a first cashew shell liquid-based polyol, a second cashew shell liquid-based polyol, and a third cashew shell liquid-based polyol, and before mixing one or more of the first cashew shell liquid-based polyol, the method further includes: The first cashew shell liquid-based polyol, the second cashew shell liquid-based polyol, and the third cashew shell liquid-based polyol are each purified independently; the purification includes impurity removal, washing, and vacuum distillation.

[0012] Optionally, in some embodiments of this application, the first cashew nutshell liquid-based polyol in the polyol composition is 0-40 parts by mass, the second cashew nutshell liquid-based polyol is 0-30 parts by mass, and the third cashew nutshell liquid-based polyol is 0-60 parts by mass, wherein at least one of the following is not 0: the mass of the first cashew nutshell liquid-based polyol, the mass of the second cashew nutshell liquid-based polyol, and the mass of the third cashew nutshell liquid-based polyol.

[0013] Accordingly, this application also provides a polyol composition, which is obtained by the preparation method of the polyol composition described above.

[0014] Accordingly, this application also provides a polyurethane composition comprising the polyol composition described above.

[0015] Optionally, in some embodiments of this application, the polyurethane composition comprises, by weight, 100 parts of the polyol composition, 14-17 parts of the foaming agent, and 130-155 parts of the isocyanate; The foaming agent includes alkane foaming agents, which include one or more of cyclopentane, isopentane, n-pentane, and cyclohexane. The isocyanate includes polymeric diphenylmethane diisocyanate, wherein the NCO content in the isocyanate is 29.5%~30.5%, and the content of polymeric diphenylmethane diisocyanate in the isocyanate is 29.5%~30.5%; the molar ratio of isocyanate groups in the isocyanate to hydroxyl groups in the polyol composition is (1.08~1.12):1; Optionally, in some embodiments of this application, the polyurethane composition further comprises, by weight, 1.1 to 1.5 parts of foam stabilizer, 0.65 to 0.95 parts of catalyst, and 5.8 to 7.2 parts of flame retardant; The foam stabilizer includes an organosilicon surfactant, which includes one or more of Momentive L-580 silicone oil, Dow Corning DC-193 silicone oil, Dow Corning DC-5043 silicone oil, and fluorinated polyglycerol ether-polydimethylsiloxane block copolymer. The catalyst comprises one or more of amine catalysts and organometallic compound catalysts. The amine catalyst comprises one or more of triethylenediamine, N,N-dimethylcyclohexylamine, N,N,N',N'-tetramethylethylenediamine, dimethylethanolamine, N,N-dimethylbenzylamine, and 2,2'-dimorpholine diethyl ether. The organometallic compound catalyst comprises one or more of dibutyltin dilaurate, zinc octanoate, bismuth isooctanoate, and tetrabutyl titanate. The flame retardant includes one or more of phosphorus-based and halogen-based flame retardants. The phosphorus-based flame retardant includes one or more of triphenyl phosphate, diethyl ethyl phosphate, dimethyl methyl phosphate, propyl dimethylphosphonate, dimethyl phosphonate, and triethyl phosphate. The halogen-based flame retardant includes tris(2-chloropropyl) phosphate.

[0016] Accordingly, this application also provides a polyurethane foam, which is obtained by foaming the polyurethane composition described above.

[0017] Optionally, in some embodiments of this application, the initial thermal conductivity of the polyurethane foam is ≤0.020 W / (m·K), and the compressive strength of the polyurethane foam is ≥150 kPa; and / or The apparent core density of the polyurethane foam is 33 kg / m³. 3 ~36 kg / m 3 Closed-cell rate ≥93%, water absorption rate ≤2.5%, low-temperature dimensional stability ≤0.8%, and damp-heat dimensional stability ≤1.2%.

[0018] Accordingly, this application also provides a refrigeration device, which includes an insulation layer made of the polyurethane foam described above.

[0019] The method for preparing the polyol composition provided in this application uses cashew nut shell liquid as raw material. Through epoxy ring-opening reaction of cashew nut shell liquid and then through a specific modification route, three highly reactive cashew nut shell liquid-based polyols are precisely synthesized. Then, these three highly reactive cashew nut shell liquid-based polyols are compounded with a single foaming agent and isocyanate to obtain a polyurethane foam with excellent environmental protection, thermal insulation and mechanical stability. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a flowchart of a method for preparing a polyol composition provided in the embodiments of this application. Detailed Implementation

[0022] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. Furthermore, it should be understood that the specific embodiments described herein are only for illustration and explanation of this application and are not intended to limit this application.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0024] In this application, unless otherwise stated, directional terms such as "upper" and "lower" generally refer to the upper and lower positions of the device in its actual use or operating state, specifically the drawing directions in the accompanying drawings; while "inner" and "outer" refer to the outline of the device. Furthermore, in the description of this application, the term "comprising" means "including but not limited to". The terms first, second, third, etc., are used merely as illustrative purposes and do not impose numerical requirements or establish a numerical order.

[0025] In this application, "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. A and B can be singular or plural.

[0026] In this application, "at least one" means one or more, and "more than one" means two or more. "One or more", "at least one of the following", or similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, "at least one of a, b, or c", or "at least one of a, b, and c", can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.

[0027] In this application, the term "on" forming another layer on a certain layer is a broad concept. It can mean that the formed other layer is adjacent to a certain layer, or it can mean that there are other spacer structures between the other layer and the certain layer. For example, when a second electrode is formed "on" a first charge carrier functional layer, the term "on" can mean that the formed second electrode is adjacent to the first charge carrier functional layer, or it can mean that there are other spacer structures between the second electrode and the first charge carrier functional layer, such as a light-emitting layer.

[0028] Various embodiments of this application may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a hard limitation on the scope of this application; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Furthermore, whenever a numerical range is referred to herein, it means including any referenced number (fraction or integer) within the referred range.

[0029] Rigid polyurethane foam is widely used in the fabrication of refrigerator insulation layers due to its excellent thermal insulation properties and lightweight, high-strength characteristics. Currently, the core raw material for rigid polyurethane foam used in refrigerators, polyols, mainly rely on petroleum-based polyols (such as polyether polyols) and some bio-based polyols (such as vegetable oil-based and sugar-based polyols). Petroleum-based polyols face challenges such as fossil resource depletion, price fluctuations, and environmental pollution. Commonly used bio-based polyols are mostly derived from sugars or vegetable oils, and their production directly competes with the food industry and biofuel production, potentially leading to resource conflicts and ecological problems (such as deforestation and fertilizer pollution).

[0030] The existing rigid polyurethane foam has the following technical problems: (1) lack of environmental protection: the carbon emissions of petroleum-based polyol raw materials are high, and the sustainability of some bio-based polyols is limited due to raw material competition; (2) the thermal insulation performance needs to be improved: the initial thermal conductivity is mostly between 0.0200 and 0.0205 W / (m·K), which is close to the upper limit of the Class I national standard and is difficult to meet the energy-saving upgrade requirements; (3) insufficient mechanical stability: the compressive strength is easy to approach 130 kPa (the lower limit of the Class I national standard) in low temperature environment (-30℃), and the box may deform after long-term use; (4) insufficient coordination between closed cell rate and dimensional stability: the dimensional stability of some products at low temperature is close to 1.0% (the upper limit of the Class I national standard), and slight deformation is easy to occur in humid and hot environment.

[0031] Therefore, the environmental friendliness, thermal insulation performance, and mechanical stability of existing rigid polyurethane foams all need further improvement.

[0032] The technical solution of this application is as follows: Firstly, please refer to Figure 1 This application provides a method for preparing a polyol composition, comprising the following steps S10-S30: S10, cashew nut shell liquid, epoxide and Lewis acid catalyst are mixed and subjected to epoxide ring-opening reaction to obtain epoxidized cashew nut shell liquid; S20, each independently employs an amination modifier, a thiol modifier, and a phosphorylation modifier to chemically modify the epoxidized cashew shell liquid, so as to obtain a first cashew shell liquid-based polyol, a second cashew shell liquid-based polyol, and a third cashew shell liquid-based polyol, respectively. S30, mix one or more of the first cashew shell liquid-based polyol, the second cashew shell liquid-based polyol, and the third cashew shell liquid-based polyol to obtain the polyol composition.

[0033] It should be noted that cashew shell liquid is a natural, dark, viscous liquid extracted from cashew shells. Its main components include cashew acid, cashew alcohol, and cashew phenol.

[0034] In this embodiment, cashew nutshell liquid-based polyols (i.e., polyols derived from cashew nutshell liquid) are prepared directly from cashew nutshell liquid. On one hand, using cashew nutshell liquid, a waste biological resource, as a raw material, with a relatively large global annual production (approximately 4 million tons), can significantly reduce the production cost of polyurethane foam, lowering the raw material cost of the polyol by 5% to 20% compared to petroleum-based polyols. On the other hand, cashew nutshell liquid-based polyols have a bio-based content of ≥60%, resulting in environmentally friendly polyols, thus reducing carbon emissions by more than 30% compared to petroleum-based polyols. Furthermore, because cashew nutshell liquid also possesses natural aromatic rings and long-chain unsaturated alkyl structures, it can impart excellent thermal stability, hydrophobicity, and mechanical properties to polyurethane foams.

[0035] To avoid impurities in the cashew shell liquid affecting the foaming uniformity, the cashew shell liquid needs to be pretreated. In some embodiments, the cashew shell liquid is further pretreated before step S10. The pretreatment includes vacuum dehydration and filtration of the cashew shell liquid in sequence, wherein the moisture content of the pretreated cashew shell liquid is ≤0.3%.

[0036] In some embodiments, the cashew shell liquid is selected from industrial-grade cashew shell liquid.

[0037] In this embodiment, industrial-grade cashew shell liquid refers to industrial-grade cashew shell liquid with a cashew phenol content of ≥70%, and the acid value of the industrial-grade cashew shell liquid is 10 mgKOH / g~15 mgKOH / g, and the moisture content is ≤0.5%.

[0038] If the cashew nut shell liquid contains less than 70% cashew nut phenol, the epoxy value of the epoxidized cashew nut shell liquid will not meet the requirements of the three modifications, thus preventing an effective improvement in the initial thermal conductivity of the final polyurethane foam. This industrial-grade cashew nut shell liquid can be commercially available cashew nut shell liquid with a cashew nut phenol content ≥70%, or it can be cashew nut shell liquid (main components include 60%~70% cashew acid, 10%~20% calcitrol, and <10% cashew nut phenol) that has undergone thermal decarboxylation treatment at 180℃~240℃ to convert the carboxyl groups of cashew acid in the cashew nut shell liquid into phenolic hydroxyl groups, resulting in an industrial-grade cashew nut shell liquid (cashew nut phenol content ≥70%, acid value 10 mgKOH / g~15 mgKOH / g, moisture content ≤0.5%).

[0039] In some embodiments, the conditions for vacuum dehydration of industrial-grade cashew nut shell liquid are: vacuum degree of -0.09 MPa to -0.095 MPa, temperature of 115 ℃ to 125 ℃, and time of 2 h to 2.5 h.

[0040] Industrial-grade cashew nut shell liquid (cashew phenol content ≥70%, acid value 10 mgKOH / g~15 mgKOH / g, moisture content ≤0.5%) was vacuum dehydrated to a moisture content less than or equal to 0.3%, and the moisture content was determined according to GB / T 6283-2008 "Determination of Moisture Content in Chemical Products - Karl Fischer Method (General Method)". Filtration after vacuum dehydration can be performed using a filter membrane to remove mechanical impurities (such as cashew nut shell fragments), which avoids affecting the uniformity of subsequent reactions. In one example, a 0.22 μm filter membrane was used to filter the vacuum-dehydrated industrial-grade cashew nut shell liquid. It should also be noted that the filter membrane used in this example does not affect the moisture content of the industrial-grade cashew nut shell liquid after vacuum dehydration. Therefore, after pretreatment (vacuum dehydration and filtration) of the industrial-grade cashew nut shell liquid (cashew phenol content ≥70%, acid value 10 mgKOH / g~15 mgKOH / g, moisture content ≤0.5%), the moisture content of the industrial-grade cashew nut shell liquid is reduced to less than or equal to 0.3%. Furthermore, the pretreatment does not affect the cashew phenol content and acid value of the industrial-grade cashew nut shell liquid, and thus will not affect the subsequent synthesis of cashew nut shell liquid-based polyols.

[0041] It is understood that the embodiments of this application use cashew nut shell liquid as raw material. After epoxidation of the cashew nut shell liquid, three highly reactive cashew nut shell liquid-based polyols are precisely synthesized through a specific modification route. After these three highly reactive cashew nut shell liquid-based polyols are compounded with a specific amount of foaming agent and isocyanate, the final polyurethane foam has excellent environmental protection, thermal insulation and mechanical stability. Specifically, the initial thermal conductivity of the final polyurethane foam can be reduced to below 0.020 W / (m·K), and the compressive strength is ≥150 kPa, which fully complies with GB / T 26689-2024 Class I standard.

[0042] In step S10, in some embodiments, the epoxide is selected from one or more of propylene oxide and epichlorohydrin, and the Lewis acid catalyst is selected from one or more of zinc chloride, aluminum chloride, and ferrous chloride.

[0043] Considering the poor controllability of aluminum chloride reaction, zinc chloride is preferably used as the Lewis acid catalyst.

[0044] In some embodiments, the epoxy ring-opening reaction is carried out at a temperature of 90°C to 95°C for a time of 4 to 6 hours.

[0045] In some embodiments, the mass ratio of the cashew nut shell liquid to the epoxide is 1:(0.75~0.9), and the amount of Lewis acid catalyst added is 0.25%~0.4% of the mass of the cashew nut shell liquid.

[0046] In some embodiments, the epoxy value of the epoxidized cashew shell liquid is 0.32 mol / 100g to 0.45 mol / 100g.

[0047] The epoxy value of the epoxidized cashew nut shell liquid is determined according to GB / T 1677-2023 "Determination of Epoxy Value of Plasticizers". The unit mol / 100g represents the number of moles of epoxy groups contained in 100g of sample. For example, the epoxy value of the epoxidized cashew nut shell liquid can be 0.32mol / 100g, 0.33mol / 100g, 0.34mol / 100g, 0.35mol / 100g, 0.36mol / 100g, 0.37mol / 100g, 0.38mol / 100g, 0.39mol / 100g, 0.40mol / 100g, 0.41mol / 100g, 0.42mol / 100g, 0.43mol / 100g, 0.44mol / 100g, 0.45mol / 100g, or any range between two of the aforementioned values.

[0048] Furthermore, since the epoxidized cashew shell liquid needs to undergo three modifications subsequently, in some embodiments, the epoxidized cashew shell liquid includes a first epoxidized cashew shell liquid for preparing the first cashew shell liquid-based polyol, a second epoxidized cashew shell liquid for preparing the second cashew shell liquid-based polyol, and a third epoxidized cashew shell liquid for preparing the third cashew shell liquid-based polyol.

[0049] The epoxy value of the first epoxidized cashew shell liquid used for amination modification is 0.32 mol / 100g to 0.36 mol / 100g, the epoxy value of the second epoxidized cashew shell liquid used for thiol modification is 0.37 mol / 100g to 0.40 mol / 100g, and the epoxy value of the third epoxidized cashew shell liquid used for phosphorylation modification is 0.41 mol / 100g to 0.45 mol / 100g.

[0050] It should be noted that in step S20, the degree of epoxidation of the epoxidized cashew shell liquid is controlled by separately controlling the time of the epoxy ring-opening reaction and the mass ratio of the reaction raw materials (the molar ratio of epoxide to phenolic hydroxyl groups in the cashew shell liquid), thereby matching different modification routes. In specific implementation, the excess proportion of epoxide is increased to improve the epoxy value; if the epoxy ring-opening reaction has not reached complete equilibrium or serious side reaction degradation has not occurred, the time of the epoxy ring-opening reaction is increased to directly control the degree of epoxidation of the epoxidized cashew shell liquid. In some embodiments, during the preparation of the first epoxidized cashew shell liquid, the time of the epoxy ring-opening reaction is 4.0 h to 4.5 h, the mass ratio of cashew shell liquid to epoxide is 1:0.75 to 1:0.85, and the amount of Lewis acid catalyst added is 0.25% to 0.35% of the mass of the cashew shell liquid. In the preparation of the second epoxidized cashew nut shell liquid, the epoxidation ring-opening reaction time is 4.5 h to 5.0 h, the mass ratio of cashew nut shell liquid to epoxide is 1:0.80 to 1:0.90, and the amount of Lewis acid catalyst added is 0.3% to 0.4% of the cashew nut shell liquid mass. In the preparation of the third epoxidized cashew nut shell liquid, the epoxidation ring-opening reaction time is 5.0 h to 6.0 h, the mass ratio of cashew nut shell liquid to epoxide is 1:0.85 to 1:0.95, and the amount of Lewis acid catalyst added is 0.3% to 0.4% of the cashew nut shell liquid mass. It should be noted that if the mass ratio of cashew nut shell liquid to epoxide does not meet the above ranges, such as if the mass of epichlorohydrin is 6 times that of the pretreated cashew nut shell liquid, the reaction will be incomplete, resulting in a lower hydroxyl value of the final polyol, thus failing to meet the requirements.

[0051] During the specific epoxidation process, samples are taken at regular intervals to test the epoxy value of the product. Once the epoxy value of the generated cashew nut shell liquid-based polyol reaches the target epoxy value, the epoxidation ring-opening reaction can be stopped.

[0052] It should also be noted that during the epoxidation of cashew nut shell liquid, the rate at which the epoxide and Lewis acid catalyst are added to the cashew nut shell liquid is 1 mL / min to 1.5 mL / min. After the cashew phenol reaction in the cashew nut shell liquid is completed (i.e., the epoxy value reaches the target epoxy value mentioned above), the products are washed with deionized water to obtain purified epoxidized cashew nut shell liquid. The purity of the purified first epoxidized cashew nut shell liquid, the purified second epoxidized cashew nut shell liquid, and the purified third epoxidized cashew nut shell liquid are all ≥98%.

[0053] Since the epoxy value of the epoxidized cashew shell liquid is controlled in step S20 of this embodiment, the cashew shell liquid can be used as the raw material for synthesizing polyols in the aforementioned step S10. There is no need to use high-purity cashew phenol extracted from the cashew shell liquid, and therefore no need to use costly high-vacuum distillation, extraction and other processes for purification. Therefore, the preparation method provided in this embodiment also has the characteristics of simple process and low cost.

[0054] After step S10, the first epoxidized cashew shell liquid, the second epoxidized cashew shell liquid, and the third epoxidized cashew shell liquid are modified respectively to obtain cashew shell liquid polyol. Therefore, in some embodiments, step S20 includes steps S21 to S23: Step S21: Mix the amination modifier and the first epoxidized cashew shell liquid, and perform a first microwave heating treatment to obtain the first cashew shell liquid-based polyol. Step S22: Under nitrogen atmosphere and ultraviolet light irradiation, the second epoxidized cashew shell liquid, the thiol modifier and the photoinitiator are mixed and subjected to a second microwave heating treatment to obtain the second cashew shell liquid-based polyol. Step S23: Mix the phosphorylation modifier and the third epoxidized cashew shell liquid, and heat-treat to obtain the third cashew shell liquid-based polyol.

[0055] It should be noted that in step S21, after the reaction between the amination modifier and the first epoxidized cashew shell liquid is completed, the epoxy value of the product can be detected. When the epoxy value of the product is ≤0.01 mol / 100g, the amination modification is considered qualified. In some embodiments, the molar ratio of the first epoxidized cashew shell liquid to the amination modifier is 1:(1.15~1.25), and the amination modifier is selected from one or more of glycine, diethanolamine, triethanolamine, isopropanolamine, tetraethylenepentamine, and triethylenetetramine.

[0056] In some embodiments, the microwave power of the first microwave heating treatment is 280W~320W, the temperature is 115℃~125℃, and the time is 2h~2.5h.

[0057] In step S32, under the action of the photoinitiator, the epoxy group of the second epoxidized cashew shell liquid undergoes a ring-opening reaction with the mercapto (-SH) group of the thiol modifier, generating one hydroxyl group at each epoxy site. In addition, the thiol modifier has one or more hydroxyl groups (such as 2-mercaptoethanol, which has one hydroxyl group), and finally each ring-opening site contributes two or more hydroxyl groups to significantly increase the hydroxyl value of the product (second cashew shell liquid-based polyol).

[0058] In some embodiments, the thiol modifier is selected from 2-mercaptoethanol; the photoinitiator is selected from one or more of 2,2-dimethoxy-2-phenylacetophenone, 2,2-dialkyl-2-hydroxyacetophenone, 2-hydroxy-2-methyl-phenylacetone, phenylbis-(2,4,6-trimethylbenzoyl)-phosphine oxide, benzophenone, and 2-isopropylthioxanthone.

[0059] During the reaction, the thiol modifier needs to be in excess to ensure that the epoxy is completely ring-opened. Therefore, in some embodiments, the molar ratio of the second epoxidized cashew shell liquid, the thiol modifier and the photoinitiator is 1:(1.8~2.0):(0.005~0.007).

[0060] It should also be noted that if thiol modification is carried out under non-nitrogen atmosphere and at room temperature (0~25 ℃), the purity of the raw material thiol modifier will decrease. Furthermore, since the reaction between the second epoxidized cashew nut shell liquid and the thiol modifier is relatively vigorous, carrying it under nitrogen atmosphere can prevent the thiol groups in the thiol modifier from being easily oxidized. In addition, the reaction temperature needs to be controlled within a certain range to avoid the volatilization of the thiol modifier. Therefore, in some embodiments, the microwave power of the second microwave heating treatment is 280W~320W, the temperature is 60℃~65℃, and the time is 24h~30h; the wavelength of the ultraviolet light is 365nm~400nm.

[0061] In step S33, in some embodiments, the molar ratio of the third epoxidized cashew shell liquid to the phosphorylation modifier is 1:(1.15~1.25).

[0062] In some embodiments, the phosphorylation modifier is selected from phosphoric acid. In this embodiment, industrial-grade phosphoric acid is selected.

[0063] In this embodiment, if the phosphorylation modifier is selected from phosphoric acid, the chemical modification of the third epoxidized cashew shell liquid with the phosphorylation modifier shall be carried out under the catalysis of triphenylphosphine. The molar ratio of the third epoxidized cashew shell liquid, phosphoric acid and triphenylphosphine is 1:(1.15~1.25):(0.005~0.01).

[0064] Specifically, the phosphoric acid hydroxyl group of the phosphorylation modifier (such as industrial-grade phosphoric acid) ring-opens with the epoxy group of the third epoxidized cashew nut shell liquid to generate one hydroxyl group. Simultaneously, the phosphoryl group (P=O) of the phosphorylation modifier (such as industrial-grade phosphoric acid) undergoes a substitution reaction with the phenolic hydroxyl group of the third epoxidized cashew nut shell liquid to release one hydroxyl group, thereby synergistically increasing the hydroxyl value of the product (third cashew nut shell liquid-based polyol). It should also be noted that this modification route introduces phosphorus into the cashew nut shell liquid-based polyol, thereby improving the flame retardant properties of polyurethane foam to a certain extent.

[0065] To further avoid the impact of impurities in the three cashew nutshell liquid-based polyols on the performance of the obtained polyurethane foam, such as the high water content of cashew nutshell liquid-based polyols causing poor thermal insulation performance of polyurethane foam, in some embodiments, after step S20 and before step S30, the following steps are also included: purifying the first cashew nutshell liquid-based polyol, the second cashew nutshell liquid-based polyol, and the third cashew nutshell liquid-based polyol independently; the purification includes impurity removal, washing, and vacuum distillation.

[0066] The purified cashew nutshell liquid-based polyols, including the first, second, and third cashew nutshell liquid-based polyols, all have a moisture content of ≤0.1%. It should also be noted that, due to the low initial moisture content of the raw materials (the moisture content of the pretreated cashew nutshell liquid is ≤0.3%), it is easier to achieve a moisture content of ≤0.1% for the cashew nutshell liquid-based polyols in this embodiment.

[0067] In this embodiment, considering the different reaction raw materials and different amounts of raw materials added for the three cashew shell liquid-based polyols, different purification methods can be adopted. In one example, the purification of the first cashew shell liquid-based polyol includes: adding deionized water to the reaction product for multiple washings, allowing it to stand and separate into layers to remove the aqueous phase; transferring the remaining oil phase to a vacuum distillation kettle for distillation to remove water, setting the vacuum degree to -0.095~-0.098MPa, raising the temperature to 105℃~115℃, and distilling to remove water for 3h~3.5h. After distilling to remove water until the water content is ≤0.1%, cooling is performed to obtain the first cashew shell liquid-based polyol (i.e., amination-modified cashew shell liquid-based polyol).

[0068] In another example, the purification of the second cashew nutshell liquid-based polyol includes: adding lithium hydroxide (LiOH) and ethanol solvent to the reaction product, stirring at room temperature (e.g., 25 °C) to neutralize acidic impurities; after neutralization, washing repeatedly with deionized water, and allowing to stand to separate the aqueous phase; transferring the remaining oil phase to a vacuum distillation vessel for distillation, setting the vacuum degree to -0.095 to -0.098 MPa, heating to 105 °C to 115 °C, and distilling for 3 to 3.5 hours. Distilling until the moisture content is ≤0.1% and then cooling to obtain the second cashew nutshell liquid-based polyol (i.e., thiol-modified cashew nutshell liquid-based polyol).

[0069] In another example, the purification of the third cashew nutshell liquid-based polyol includes: adjusting the pH of the reaction product to 6.5-7.0 with deionized water to neutralize excess industrial-grade phosphoric acid; allowing the mixture to stand and separate into layers to remove the aqueous phase; adding anhydrous ethanol to the remaining oil phase for recrystallization; and then filtering to remove unreacted raw materials and catalyst residue. Finally, the mixture is transferred to a vacuum distillation vessel for distillation to remove deionized water and anhydrous ethanol. The vacuum level is set to -0.095 to -0.098 MPa, the temperature is raised to 110°C-120°C, and the distillation time is 3-3.5 hours. After distillation until the moisture content is ≤0.1%, the mixture is cooled to obtain the third cashew nutshell liquid-based polyol (i.e., phosphorylated modified cashew nutshell liquid-based polyol).

[0070] It should be noted that this application obtains cashew nutshell liquid-based polyols with a certain hydroxyl value by controlling the epoxy value in the epoxidized cashew nutshell liquid and a specific modification route, thereby adapting to the preparation requirements of GB / T 26689-2024 Class I polyurethane foam. Therefore, in one embodiment, the hydroxyl value of the first cashew nutshell liquid-based polyol is 345 mgKOH / g~355 mgKOH / g, the hydroxyl value of the second cashew nutshell liquid-based polyol is 395 mgKOH / g~405 mgKOH / g, and the hydroxyl value of the third cashew nutshell liquid-based polyol is 415 mgKOH / g~425 mgKOH / g.

[0071] In this embodiment, a highly precise and highly reactive cashew nutshell liquid-based polyol was obtained by epoxidizing cashew nutshell liquid and then proceeding through a specific modification route. Precise control of the hydroxyl value avoids insufficient crosslinking density, thus solving the problem of unstable performance of existing bio-based polyols. It should be noted that high precision refers to a hydroxyl value fluctuation ≤ ±5 mgKOH / g. If the hydroxyl value of the cashew nutshell liquid-based polyol fluctuates too much, for example, if the hydroxyl value of the first, second, or third cashew nutshell liquid-based polyol is 250 mgKOH / g to 360 mgKOH / g, the initial crosslinking density of the polyurethane foam will be insufficient. Furthermore, in this embodiment, factors affecting the hydroxyl value of the cashew nutshell liquid-based polyol include the modifying reagent; different modifying reagents and their modification routes determine the hydroxyl value range of the synthesized polyol.

[0072] The hydroxyl value is determined according to GB / T 12008.3-2009 "Polyether Polyols - Part 3: Determination of Hydroxyl Value". For example, the hydroxyl value of the first cashew nutshell liquid-based polyol can be 345 mgKOH / g, 346 mgKOH / g, 347 mgKOH / g, 348 mgKOH / g, 349 mgKOH / g, 350 mgKOH / g, 351 mgKOH / g, 352 mgKOH / g, 353 mgKOH / g, 354 mgKOH / g, 355 mgKOH / g, or any range between two of the aforementioned values. The hydroxyl value of the second cashew nutshell liquid-based polyol can be 395 mgKOH / g, 396 mgKOH / g, 397 mgKOH / g, 398 mgKOH / g, 399 mgKOH / g, 400 mgKOH / g, 401 mgKOH / g, 402 mgKOH / g, 403 mgKOH / g, or any range between two of the aforementioned values. The hydroxyl value of the third cashew nutshell liquid-based polyol can be 415 mgKOH / g, 416 mgKOH / g, 417 mgKOH / g, 418 mgKOH / g, 419 mgKOH / g, 420 mgKOH / g, 421 mgKOH / g, 422 mgKOH / g, 423 mgKOH / g, 424 mgKOH / g, 425 mgKOH / g, or any two of the aforementioned values.

[0073] It should also be noted that the synthesis route provided in this embodiment (epoxidation of raw materials and specific modification route) results in three cashew nutshell liquid-based polyols with low acid values, thus meeting the preparation requirements of GB / T 26689-2024 Class I polyurethane foam. This reduces catalyst loss while improving foam structural uniformity and dimensional stability. In one embodiment, the acid value of the first cashew nutshell liquid-based polyol is ≤0.08 mgKOH / g, the acid value of the second cashew nutshell liquid-based polyol is ≤0.08 mgKOH / g, and the acid value of the third cashew nutshell liquid-based polyol is ≤0.09 mgKOH / g.

[0074] For example, the acid value of the first cashew shell liquid-based polyol can be 0.08 mg KOH / g, 0.06 mg KOH / g, 0.05 mg KOH / g, 0.04 mg KOH / g, 0.01 mg KOH / g, or any range between two of the aforementioned values; the acid value of the second cashew shell liquid-based polyol can be 0.08 mg KOH / g, 0.06 mg KOH / g, 0.05 mg KOH / g, 0.04 mg KOH / g, 0.01 mg KOH / g, or any range between two of the aforementioned values; and the acid value of the third cashew shell liquid-based polyol can be 0.09 mg KOH / g, 0.08 mg KOH / g, 0.06 mg KOH / g, 0.05 mg KOH / g, 0.04 mg KOH / g, 0.01 mg KOH / g, or any range between two of the aforementioned values.

[0075] Furthermore, by employing the synthesis route provided in this embodiment (epoxidation of raw materials and specific modification route), the molecular weight of the three cashew nutshell liquid-based polyols obtained is effectively adjusted, thereby controlling the viscosity of the cashew nutshell liquid-based polyols within a certain range. This adapts to the preparation requirements of GB / T 26689-2024 Class I polyurethane foam, resulting in polyurethane foams with good processability and foam uniformity. In some embodiments, the viscosities of the first, second, and third cashew nutshell liquid-based polyols at 25°C are each independently selected from 15 Pa·s to 30 Pa·s.

[0076] Viscosity was determined according to GB / T 10247-2008 "Viscosity Measurement Method". The viscosity of the first cashew shell liquid-based polyol can be 15 Pa·s, 18 Pa·s, 20 Pa·s, 25 Pa·s, 30 Pa·s or any two of the aforementioned values. The viscosity of the second cashew shell liquid-based polyol can be 15 Pa·s, 18 Pa·s, 20 Pa·s, 25 Pa·s, 30 Pa·s or any two of the aforementioned values. The viscosity of the third cashew shell liquid-based polyol can be 15 Pa·s, 18 Pa·s, 20 Pa·s, 25 Pa·s, 30 Pa·s or any two of the aforementioned values.

[0077] In some embodiments, the number average molecular weight of the first cashew nutshell liquid-based polyol is 600 g / mol to 800 g / mol; the number average molecular weight of the second cashew nutshell liquid-based polyol is 700 g / mol to 850 g / mol; and the number average molecular weight of the third cashew nutshell liquid-based polyol is 750 g / mol to 900 g / mol.

[0078] The number-average molecular weight was determined using the national standard GB / T 36214-2018. For example, the number-average molecular weight of the first cashew nutshell liquid-based polyol can be 600 g / mol, 650 g / mol, 700 g / mol, 750 g / mol, 800 g / mol, or any range between two of the aforementioned values; the number-average molecular weight of the second cashew nutshell liquid-based polyol can be 700 g / mol, 750 g / mol, 800 g / mol, 850 g / mol, or any range between two of the aforementioned values; and the number-average molecular weight of the third cashew nutshell liquid-based polyol can be 750 g / mol, 800 g / mol, 850 g / mol, 900 g / mol, or any range between two of the aforementioned values.

[0079] In some embodiments, when compounding three different cashew nut shell liquid-based polyols, the first cashew nut shell liquid-based polyol comprises 0-40 parts by mass, the second cashew nut shell liquid-based polyol comprises 0-30 parts by mass, and the third cashew nut shell liquid-based polyol comprises 0-60 parts by mass, wherein at least one of the following three cashew nut shell liquid-based polyols is not zero: the first cashew nut shell liquid-based polyol, the second cashew nut shell liquid-based polyol, and the third cashew nut shell liquid-based polyol.

[0080] In this embodiment, when the polyol composition includes one or more cashew nutshell liquid-based polyols with different hydroxyl values, the performance of the final polyurethane foam will be improved to varying degrees. The first epoxy cashew nutshell liquid with a low epoxy value is used to provide basic toughness, the second epoxy cashew nutshell liquid with a medium epoxy value is used to balance strength and thermal conductivity, and the third epoxy cashew nutshell liquid with a high epoxy value is used to obtain a third cashew nutshell liquid-based polyol with a high hydroxyl value, thereby strengthening the cell wall strength to improve the closed-cell rate and low water absorption rate, while improving the storage stability of the third cashew nutshell liquid-based polyol to reduce the degree to which the phenolic hydroxyl groups of the third cashew nutshell liquid-based polyol are easily oxidized by oxygen in the air. On the other hand, it is used to leave "space" for the subsequent introduction of a large number of functional groups (phosphate groups) to improve the flame retardant performance of the polyurethane foam to a certain extent.

[0081] In one example, when the polyol composition includes one of the first cashew nutshell liquid-based polyol, the second cashew nutshell liquid-based polyol, and the third cashew nutshell liquid-based polyol, the resulting polyurethane foam has an initial thermal conductivity of 0.0197 W / (m·K) to 0.0199 W / (m·K) and a compressive strength of 155 kPa to 170 kPa.

[0082] In another example, when the polyol composition includes two or three of the first cashew nutshell liquid-based polyol, the second cashew nutshell liquid-based polyol, and the third cashew nutshell liquid-based polyol, the resulting polyurethane foam has an initial thermal conductivity that is stable below 0.019 W / (m·K) and a compressive strength that is stable above 170 kPa.

[0083] Compared to the first example, the polyurethane foam obtained in this second example exhibits superior thermal insulation and mechanical stability. Preferably, the polyol composition comprises a first cashew nutshell liquid-based polyol and a third cashew nutshell liquid-based polyol, wherein the mass ratio of the first cashew nutshell liquid-based polyol to the third cashew nutshell liquid-based polyol is 1:1 to 4:6.

[0084] Secondly, embodiments of this application also provide a polyol composition, which is obtained by the preparation method of the polyol composition described above.

[0085] Understandably, by employing the preparation method described above, cashew nut shell liquid, a waste byproduct of the cashew processing industry, can be used as a raw material for the synthesis of polyols, thereby obtaining an environmentally friendly polyol composition. This environmentally friendly polyol composition can then be used as the core bio-based raw material for polyurethane foam, significantly reducing the production cost of polyurethane foam. Furthermore, the preparation method for the polyol composition provided above allows for precise control of parameters such as hydroxyl value, acid value, and viscosity, meeting the preparation requirements of GB / T 26689-2024 Class I standard.

[0086] Thirdly, embodiments of this application also provide a polyurethane composition comprising the polyol composition described above.

[0087] The polyurethane composition provided in this embodiment includes a polyol composition whose reactivity is matched with that of isocyanates. Furthermore, because the polyol composition is obtained through amination, thiol modification, or phosphorylation modification, the highly reactive polyol composition can control the cell uniformity at low blowing agent dosages. This results in an initial thermal conductivity of the final polyurethane foam that is below 0.020 W / (m·K) and a compressive strength ≥150 kPa, thus solving the technical problem of insufficient synergy between thermal insulation and mechanical properties in polyurethane foam. In addition, because the compressive strength of the polyurethane foam is ≥150 kPa, its low-temperature dimensional stability is ≤0.8%, its damp-heat dimensional stability is ≤1.2%, and its water absorption is ≤2.5%, all of which are superior to the requirements of GB / T26689-2024 Class I standard.

[0088] In order to achieve precise control of the performance of polyurethane foam, in some embodiments, the polyurethane composition includes 100 parts of the polyol composition, 14 to 17 parts of the blowing agent and 130 to 155 parts of the isocyanate by weight.

[0089] For example, the mass fraction of the foaming agent can be 14 parts, 15 parts, 16 parts, 17 parts, or any range between any two of the aforementioned values, and the mass fraction of the isocyanate can be 130 parts, 132 parts, 135 parts, 136 parts, 138 parts, 140 parts, 142 parts, 145 parts, 150 parts, 155 parts, or any range between any two of the aforementioned values.

[0090] In this embodiment, by adjusting the amount of foaming agent to a low level, the apparent core density of the polyurethane foam was finely adjusted. Specifically, the apparent core density of the polyurethane foam was 33 kg / m³. 3 ~36 kg / m 3 In some embodiments, the blowing agent comprises an alkane blowing agent, which includes one or more of cyclopentane, isopentane, n-pentane, and cyclohexane.

[0091] In some embodiments, the isocyanate includes polymeric diphenylmethane diisocyanate, wherein the NCO content in the isocyanate is 29.5%~30.5%, and the content of polymeric diphenylmethane diisocyanate in the isocyanate is 29.5%~30.5%; the molar ratio of isocyanate groups in the isocyanate to hydroxyl groups in the polyol composition is (1.08~1.12):1.

[0092] In this embodiment, the molar ratio of isocyanate groups (-NCO) in the isocyanate to hydroxyl groups (-OH) in the polyol composition directly affects the degree of crosslinking and performance of the polyurethane foam. Within the specified range, nucleation foaming can be performed effectively to prepare polyurethane foam. The content of isocyanate groups (-NCO) is determined according to GB / T 44571-2024 "Test Methods for Artificial Leather and Synthetic Leather: Determination of Free Isocyanate Content", and the content of hydroxyl groups (-OH) is determined according to GB / T 12008.3-2009 "Plastics - Polyether Polyols - Part 3: Determination of Hydroxyl Value". For example, the molar ratio of isocyanate groups in the isocyanate to hydroxyl groups in the polyol composition can be 1.08:1, 1.09:1, 1.1:1, 1.11:1, 1.12:1, or any range between the aforementioned values.

[0093] In addition, to further improve the overall performance of polyurethane foam, in some embodiments, the polyurethane composition further includes 1.1 to 1.5 parts by weight of foam stabilizer, 0.65 to 0.95 parts by weight of catalyst and 5.8 to 7.2 parts by weight of flame retardant.

[0094] For example, the mass fraction of the foam stabilizer can be 1.1 parts, 1.2 parts, 1.3 parts, 1.4 parts, 1.5 parts, or any range between any two of the aforementioned values; the mass fraction of the catalyst can be 0.65 parts, 0.70 parts, 0.75 parts, 0.80 parts, 0.85 parts, 0.90 parts, 0.95 parts, or any range between any two of the aforementioned values; and the mass fraction of the flame retardant can be 5.8 parts, 5.9 parts, 6.0 parts, 6.1 parts, 6.2 parts, 6.5 parts, 6.8 parts, 7.0 parts, 7.2 parts, or any range between any two of the aforementioned values.

[0095] The foam stabilizer includes an organosilicon surfactant, which includes one or more of Momentive L-580 silicone oil, Dow Corning DC-193 silicone oil, Dow Corning DC-5043 silicone oil, and fluorinated polyglycerol ether-polydimethylsiloxane block copolymer.

[0096] Furthermore, the silicone surfactant is a silicone surfactant with a hydrophilic-lipophilic balance number (HLB value) of 4 to 6. Even further, by synergistically combining a highly reactive polyol composition with a silicone surfactant having an HLB value of 5, the closed-cell rate of the polyurethane foam can be ensured to be ≥93%.

[0097] In some embodiments, the catalyst comprises one or more of amine catalysts and organometallic compound catalysts. The amine catalysts include one or more of triethylenediamine, N,N-dimethylcyclohexylamine, N,N,N',N'-tetramethylethylenediamine, dimethylethanolamine, N,N-dimethylbenzylamine, and 2,2'-dimorpholine diethyl ether. The organometallic compound catalysts include one or more of dibutyltin dilaurate, zinc octanoate, bismuth isooctanoate, and tetrabutyl titanate.

[0098] Flame retardants include one or more of phosphorus-based and halogen-based flame retardants. Phosphorus-based flame retardants include one or more of triphenyl phosphate, diethyl ethyl phosphate, dimethyl methyl phosphate, propyl dimethylphosphonate, dimethyl phosphonate, and triethyl phosphate. Halogen-based flame retardants include tris(2-chloropropyl) phosphate.

[0099] Fourthly, embodiments of this application also provide a polyurethane foam, which is obtained by foaming the polyurethane composition described above.

[0100] Since this polyurethane foam adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be repeated here.

[0101] In some embodiments, the initial thermal conductivity of the polyurethane foam is ≤0.020 W / (m·K), and the compressive strength of the polyurethane foam is ≥150 kPa; and / or The apparent core density of the polyurethane foam is 33 kg / m³. 3 ~36 kg / m 3 Closed-cell rate ≥93%, water absorption rate ≤2.5%, low-temperature dimensional stability ≤0.8%, and damp-heat dimensional stability ≤1.2%.

[0102] The apparent core density was measured according to the national standard GB / T 6343-2009. For example, the apparent core density of polyurethane foam is 33 kg / m³. 3 34 kg / m 3 35 kg / m 3 36 kg / m 3 Or a range between any two values, etc. Within this range, polyurethane foam exhibits excellent mechanical and thermal insulation properties.

[0103] Fifthly, embodiments of this application also provide a method for preparing polyurethane foam, comprising the following steps S101~S103: Step S101: Provide a certain number of parts of polyol composition, foaming agent, foam stabilizer, catalyst and flame retardant; Step S102: Mix the polyol composition, foaming agent, foam stabilizer, catalyst and flame retardant to obtain a premixed liquid; Step S103: The premixed liquid is mixed with isocyanate and foamed to obtain polyurethane foam.

[0104] In step S102, in some embodiments, the mixing speed of the polyol composition, foaming agent, foam stabilizer, catalyst and flame retardant is 750 rpm to 850 rpm, and the mixing time is 2.5 min to 3.5 min.

[0105] In some embodiments, the mixing speed of the premixed liquid and isocyanate is 1400 rpm to 1600 rpm, and the mixing time is 11 s to 13 s.

[0106] In some embodiments, step S103 includes: mixing the premixed liquid with isocyanate, injecting it into a mold, allowing it to stand and cure for 13 min to 17 min at a temperature of 20°C to 30°C, transferring the cured rigid foam along with the mold into a curing oven, curing at 55°C to 65°C for 1.5 h to 3 h, and demolding it after it cools naturally to room temperature to obtain polyurethane foam.

[0107] In this embodiment, by controlling the molar ratio of NCO in isocyanate to OH in the polyol composition to be 1.08:1~1.12:1, using a low amount of foaming agent, and combining it with a catalyst and flame retardant, and by precisely controlling the stirring speed, foaming and curing temperature, and curing process, an initial thermal conductivity ≤0.020W / (m·K) and an apparent core density of 33 kg / m³ were prepared. 3 ~36 kg / m 3 GB / T 26689-2024 Class I polyurethane foam.

[0108] Sixthly, embodiments of this application also provide a refrigeration device, the refrigeration device including a heat insulation layer, the heat insulation layer being made of the polyurethane foam described above.

[0109] Because the polyurethane foam provided in this embodiment has excellent environmental protection, thermal insulation and mechanical stability, it fully complies with GB / T 26689-2024 Class I standard. Therefore, the polyurethane foam can be directly applied to the integrated molding of the insulation layer of the refrigerator body and door, and the process is compatible with existing refrigerator production lines.

[0110] In some embodiments, the thickness of the insulation layer is 25-50 mm. This application does not specifically limit the thickness of the insulation layer; it can be adjusted according to the requirements of the refrigeration equipment (such as a refrigerator).

[0111] Furthermore, since this refrigeration equipment adopts all the technical solutions of all the above embodiments, it possesses at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be elaborated upon here. The refrigeration equipment can be various refrigeration and insulation equipment such as household refrigerators, cold chain refrigerators, freezers, and refrigerated trucks.

[0112] The present application will be specifically described below through specific embodiments. These embodiments are only some embodiments of the present application and are not intended to limit the present application. Unless otherwise specified, the raw materials used in the following embodiments are all commercially available products.

[0113] Preparation of the first cashew shell liquid-based polyol Pretreatment of cashew shell liquid: Take industrial-grade cashew shell liquid (acid value 10 mg KOH / g, moisture content 0.5%, cashew phenol content 80%), put it into a vacuum dehydration kettle, set the vacuum degree to -0.095 MPa, heat to 125℃, keep it at this temperature for 2.5h, monitor the moisture content in real time until the moisture content is 0.3%, and cool it to 65℃ for later use; After dehydration, the cashew shell liquid needs to be filtered through a 0.22μm filter membrane to remove mechanical impurities (such as cashew shell fragments) to avoid affecting the uniformity of subsequent reactions.

[0114] Pretreated cashew shell liquid was added to a four-necked flask equipped with a stirrer, thermometer, and dropping funnel. Stirring was started (300 rpm), and the temperature was raised to 95°C. The pretreated cashew shell liquid and epichlorohydrin were mixed at a mass ratio of 1:0.85, and epichlorohydrin was slowly added dropwise (dropping rate 1 mL / min). At the same time, ZnCl2 catalyst (0.25% of the mass of the pretreated cashew shell liquid) was added. After the addition was completed, the reaction was maintained at 95°C for 4 hours. The epoxy value was measured every 30 minutes. When the epoxy value reached 0.36 mol / 100g (the reaction time for the epoxy ring-opening reaction was 4 hours), the reaction was stopped, and the first epoxidized cashew shell liquid was obtained. After the reaction was completed, deionized water was added and washed three times (water-to-liquid ratio 1:1). After standing and separating the layers, the aqueous phase was removed to obtain the purified first epoxidized cashew shell liquid (purity 98%).

[0115] The refined first epoxidized cashew shell liquid was transferred to a microwave reactor, and diethanolamine (DEA) was added. The molar ratio of the refined first epoxidized cashew shell liquid to DEA was controlled at 1:1.15. The microwave power was set to 320 W, the temperature was raised to 125℃, and the reaction was maintained at this temperature for 2.5 h. During this period, the mixture was stirred every 20 min (200 rpm for 10 s) to ensure uniform reaction. After the reaction was completed, the mixture was cooled to room temperature (25℃), and the epoxy value was measured to be 0.01 mol / 100g, which indicates that the amination modification was qualified.

[0116] The reaction product was washed three times with deionized water (water-to-material ratio 1:1), and the aqueous phase was separated after standing for 30 minutes. The oil phase was transferred to a vacuum distillation vessel, the vacuum was set to -0.098 MPa, the temperature was raised to 115℃, and the water was removed by distillation for 3.5 hours until the water content was 0.1%. The product was then cooled to below 40℃ to obtain the first cashew shell liquid-based polyol (amine-modified cashew shell liquid-based polyol).

[0117] The first cashew nut shell liquid-based polyol has a hydroxyl value of 350 mgKOH / g, an acid value of 0.08 mgKOH / g, a viscosity of 22 Pa·s (25℃), a number-average molecular weight of 600 g / mol, and a moisture content of 0.1%.

[0118] Preparation of Second Cashew Shell Liquid Polyol Pretreatment of cashew shell liquid: Take industrial-grade cashew shell liquid (acid value 10 mg KOH / g, moisture content 0.5%, cashew phenol content 80%), put it into a vacuum dehydration kettle, set the vacuum degree to -0.095 MPa, heat to 125℃, keep it at this temperature for 2.5h, monitor the moisture content in real time until the moisture content is 0.3%, and cool it to 65℃ for later use; After dehydration, the cashew shell liquid needs to be filtered through a 0.22μm filter membrane to remove mechanical impurities (such as cashew shell fragments) to avoid affecting the uniformity of subsequent reactions.

[0119] Pretreated cashew shell liquid was added to a four-necked flask equipped with a stirrer, thermometer, and dropping funnel. Stirring was started (300 rpm), and the temperature was raised to 95°C. The pretreated cashew shell liquid and epichlorohydrin were mixed at a mass ratio of 1:0.9, and epichlorohydrin was slowly added dropwise (dropping rate 1 mL / min). At the same time, ZnCl2 catalyst (0.35% of the mass of the pretreated cashew shell liquid) was added. After the addition was completed, the reaction was maintained at 95°C for 5 hours. The epoxy value was measured every 30 minutes. When the epoxy value reached 0.40 mol / 100g (to reserve sites for introducing more hydroxyl groups) (the reaction time for the epoxy ring-opening reaction was 4.5 hours), the reaction was stopped, and the second epoxidized cashew shell liquid was obtained. After the reaction was completed, deionized water was added and washed three times (water-to-liquid ratio 1:1). After standing and separating the layers, the aqueous phase was removed to obtain the purified second epoxidized cashew shell liquid (purity 98%).

[0120] The refined second epoxidized cashew shell liquid was transferred into a microwave reactor. The mixture was fed in a molar ratio of refined second epoxidized cashew shell liquid: 2-mercaptoethanol: 2,2-dimethoxy-2-phenylacetophenone (photoinitiator) of 1:1.8:0.005 (2-mercaptoethanol was added in excess to ensure complete ring opening of the epoxy). Under nitrogen protection, the mixture was irradiated with UV light at a wavelength of 365 nm and a power of 300 W, and the temperature was controlled at 65℃ (to avoid thiol volatilization). The reaction was carried out for 24 h.

[0121] Add 5 wt% lithium hydroxide (LiOH) to the reaction product, using ethanol as solvent, and stir at room temperature for 4 hours to neutralize trace acidic impurities; then wash three times with deionized water (water-to-material ratio 1:1), and separate the aqueous phase after standing for 30 minutes; transfer the oil phase to a vacuum distillation vessel, set the vacuum degree to -0.098 MPa, raise the temperature to 115℃, and distill for 3.5 hours until the water content is 0.1%; cool to below 40℃ to obtain the second cashew shell liquid-based polyol (thiol-modified cashew shell liquid-based polyol) product.

[0122] The second cashew nut shell liquid-based polyol has a hydroxyl value of 400 mgKOH / g, an acid value of 0.08 mgKOH / g, a viscosity of 25 Pa·s (25℃), a number-average molecular weight of 700 g / mol, and a moisture content of 0.1%.

[0123] Preparation of the third cashew shell liquid-based polyol Pretreatment of cashew shell liquid: Take industrial-grade cashew shell liquid (acid value 10 mg KOH / g, moisture content 0.5%, cashew phenol content 80%), put it into a vacuum dehydration kettle, set the vacuum degree to -0.095 MPa, heat to 125℃, keep it at this temperature for 2.5h, monitor the moisture content in real time until the moisture content is 0.3%, and cool it to 65℃ for later use; After dehydration, the cashew shell liquid needs to be filtered through a 0.22μm filter membrane to remove mechanical impurities (such as cashew shell fragments) to avoid affecting the uniformity of subsequent reactions.

[0124] Pretreated cashew nut shell liquid was added to a four-necked flask equipped with a stirrer, thermometer, and dropping funnel. Stirring was started (300 rpm), and the temperature was raised to 95°C. The pretreated cashew nut shell liquid was mixed with epichlorohydrin at a mass ratio of 1:0.95, and epichlorohydrin was slowly added dropwise (1 mL / min). Simultaneously, ZnCl2 catalyst (0.35% of the mass of the pretreated cashew nut shell liquid) was added. After the addition was complete, the reaction was maintained at 95°C for 6 hours. The epoxy value was measured every 30 minutes. When the epoxy value reached 0.42 mol / 100g (compared to the second epoxidized cashew nut shell liquid, the third epoxidized cashew nut shell liquid had a higher epoxy value, providing a basis for the introduction of more hydroxyl groups through phosphorylation) (the reaction time for the epoxy ring-opening reaction was 5.5 minutes). The reaction was stopped at h) to obtain the third epoxidized cashew shell liquid; after the reaction was completed, deionized water was added and washed 3 times (water-to-material ratio 1:1), and after standing and separating into layers, the aqueous phase was removed to obtain the refined third epoxidized cashew shell liquid (purity 98%).

[0125] Add the refined third epoxidized cashew nut shell liquid to a four-necked flask, heat to 85°C, and add the raw materials at a molar ratio of refined third epoxidized cashew nut shell liquid: 85% industrial grade phosphoric acid: triphenylphosphine (catalyst) of 1:1.2:0.01 (85% industrial grade phosphoric acid in excess). Maintain the temperature for 6.5 hours, stirring once every 30 minutes (300 rpm for 10 seconds) to ensure uniform reaction.

[0126] Deionized water was added to the reaction product to adjust the pH to 7.0 to neutralize excess phosphoric acid. After standing for 30 minutes, the aqueous phase was separated. Anhydrous ethanol was added to the oil phase for recrystallization (reaction product: ethanol mass ratio 1:3). After filtration to remove unreacted raw materials and catalyst residue, the product was transferred to a vacuum distillation kettle. The vacuum degree was set to -0.098 MPa, the temperature was raised to 120℃, and the product was distilled for 3 hours until the water content was 0.1%. The product was then cooled to below 40℃ to obtain the third cashew nut shell liquid-based polyol (phosphorylated modified cashew nut shell liquid-based polyol).

[0127] The third cashew nut shell liquid-based polyol has a hydroxyl value of 420 mgKOH / g, an acid value of 0.09 mgKOH / g, a viscosity of 28 Pa·s (25℃), a phosphorus content of 2.5~3.0 wt%, a number average molecular weight of 750 g / mol, and a moisture content of 0.1%.

[0128] Example 1 100 parts of a polyol composition (the first cashew shell liquid-based polyol prepared above, i.e., the amination-modified cashew shell liquid-based polyol, with a hydroxyl value of 350 mgKOH / g and a viscosity of 22 Pa·s), 15 parts of cyclopentane (purity ≥99.5%, moisture ≤0.05%), 0.8 parts of triethylenediamine (purity ≥99%), 0.7 parts of dibutyltin dilaurate (Sn content 18%), 1.2 parts of organosilicon surfactant (HLB=5, viscosity 500 mPa·s), and 6 parts of triphenyl phosphate (phosphorus content 8.5%, purity ≥99%) were added to a high-speed stirring tank. The ambient temperature was controlled at 23℃ and the relative humidity at 40%. The mixture was stirred at 800 rpm for 3 min to ensure uniform mixing (no visible particles, viscosity 500 mPa·s) to obtain a premixed solution.

[0129] Add 132 parts of polymeric diphenylmethane diisocyanate (polymeric MDI, NCO content 30%, 2,4'-MDI content 40%) (NCO / OH molar ratio 1.10:1) rapidly to the premixed liquid over 10 seconds. Immediately increase the stirring speed to 1500 rpm and stir for 12 seconds. Then quickly pour the mixture into a refrigerator mold (mold temperature 35 ℃, mold inner wall coated with release agent, thickness 0.1 mm).

[0130] The polyurethane rigid foam was cured by allowing it to stand at room temperature (25℃) for 15 minutes, during which the peak temperature rise of the foam was monitored to be ≤80℃ (to avoid excessive reaction that could lead to performance degradation).

[0131] The cured polyurethane rigid foam, along with the mold, was transferred into a curing oven and cured at 60 ℃ for 2 h. After naturally cooling to room temperature, it was demolded to obtain a refrigerator polyurethane rigid foam insulation layer with a thickness of 30 mm.

[0132] Example 2 The difference between this embodiment and Example 1 is that the polyol composition uses the second cashew shell liquid-based polyol prepared above (i.e., thiol-modified cashew shell liquid-based polyol, hydroxyl value 400 mgKOH / g, viscosity 25 Pa·s), the amount of polymerized diphenylmethane diisocyanate is 152 parts (NCO / OH molar ratio is 1.11:1), the amount of cyclopentane is 16 parts, and the amount of organosilicon surfactant is 1.3 parts.

[0133] Example 3 The difference between this embodiment and Example 1 is that the polyol composition uses the third cashew shell liquid-based polyol prepared above (i.e., phosphorylated modified cashew shell liquid-based polyol, hydroxyl value 420 mgKOH / g, viscosity 28 Pa·s), the amount of polymeric diphenylmethane diisocyanate is 161 parts (NCO / OH molar ratio is 1.12:1), the amount of cyclopentane is 14 parts, the amount of triethylenediamine is 0.9 parts, the amount of dibutyltin dilaurate is 0.8 parts, the amount of organosilicon surfactant is 1.4 parts, and the amount of triphenyl phosphate is 7 parts.

[0134] Example 4 The difference between this embodiment and Example 1 is that the polyol composition uses 40 parts of the first cashew shell liquid-based polyol prepared above (i.e., amination-modified cashew shell liquid-based polyol, hydroxyl value 400 mgKOH / g, viscosity 25 Pa·s) and 60 parts of the third cashew shell liquid-based polyol prepared above (i.e., phosphorylation-modified cashew shell liquid-based polyol, hydroxyl value 420 mgKOH / g, viscosity 28 Pa·s), and the amount of polymerized diphenylmethane diisocyanate is 148 parts (NCO / OH molar ratio is 1.10:1).

[0135] Example 5 The difference between this embodiment and Example 1 is that the polyol composition uses 20 parts of the first cashew shell liquid-based polyol prepared above (i.e., amination-modified cashew shell liquid-based polyol, hydroxyl value 400 mgKOH / g, viscosity 25 Pa·s), 30 parts of the second cashew shell liquid-based polyol prepared above (i.e., thiol-modified cashew shell liquid-based polyol, hydroxyl value 400 mgKOH / g, viscosity 25 Pa·s), and 40 parts of the third cashew shell liquid-based polyol prepared above (i.e., phosphorylation-modified cashew shell liquid-based polyol, hydroxyl value 420 mgKOH / g, viscosity 28 Pa·s), and the amount of polymerized diphenylmethane diisocyanate is 151 parts (NCO / OH molar ratio is 1.10:1).

[0136] Comparative Example 1 The difference between this comparative example and Example 1 is that the polyol composition uses a commonly used petroleum-based polyether polyol (the hydroxyl value and viscosity do not meet the ranges provided in this application), the mass fraction of polymeric diphenylmethane diisocyanate does not meet the ranges provided in this application, and the mass fraction of the blowing agent cyclopentane does not meet the ranges provided in this application. Specifically, the polyol composition uses a petroleum-based polyether polyol (hydroxyl value 300 mgKOH / g, viscosity 18 Pa·s, number average molecular weight 700 g / mol), the mass fraction of polymeric diphenylmethane diisocyanate is 111 parts (NCO / OH molar ratio is 1.08:1), and the mass fraction of cyclopentane is 20 parts.

[0137] Comparative Example 2 The difference between this comparative example and Example 1 is that the polyol composition uses a commonly used vegetable oil-based polyol (the hydroxyl value and viscosity do not meet the ranges provided in this application), and the amount of cyclopentane as a blowing agent does not meet the ranges provided in this application. Specifically, the polyol composition uses a vegetable oil-based polyol (hydroxyl value 280 mgKOH / g, viscosity 20 Pa·s, derived from soybean oil), the amount of polymeric diphenylmethane diisocyanate is 106 parts (NCO / OH molar ratio is 1.10:1), and the amount of cyclopentane is 19 parts.

[0138] The polyurethane composition formulations of Examples 1-5 and Comparative Examples 1-2 are shown in Table 1 below.

[0139] Table 1 Formulation of Polyurethane Compositions in Examples and Comparative Examples

[0140] The polyurethane foams obtained in Examples 1-5 and Comparative Examples 1-2 were subjected to performance tests. The performance test results of each example and comparative example are shown in Table 2. The performance test items included: initial thermal conductivity, compressive strength, apparent core density, closed-cell rate, water absorption rate, dimensional stability, and high and low temperature cycling performance.

[0141] The testing methods for each performance aspect are as follows: Initial thermal conductivity (λ0): According to GB / T 26689-2024, the thermal conductivity of polyurethane foam within 72 h of production (average temperature 10℃) is tested, and the unit is W / (m·K). Compressive strength (σ) c ): Tested according to GB / T 26689-2024, the compressive stress (minimum values ​​in the length, width, and height directions) of the sample when it is 10% deformed, in kPa, is used to reflect the structural stability of polyurethane foam. Apparent core density (ρ): Tested according to GB / T 6343-2009, unit is kg / m³ 3 Class I rigid polyurethane foam requires a strength of ≤36 kg / m³. 3 ; Closed-cell ratio (θ): Tested according to GB / T 10799-2008 "Determination of open-cell and closed-cell volume percentage of rigid foamed plastics", unit is %, Class I rigid polyurethane foam requires a closed-cell ratio of ≥90%; Water absorption rate: Determined according to GB / T 8810-2005 by measuring the buoyancy of polyurethane foam after immersion in water for 50 mm and 96 hours, with the unit being % . Dimensional stability: Tested according to GB / T 8811-2008, including low-temperature dimensional change rate (test conditions: temperature -30±2℃, time 24h) and damp-heat dimensional change rate (test conditions: temperature 70±2℃, relative humidity 95±5%, time 24h), in percentage. For Class I rigid foam, the low-temperature dimensional change rate is required to be ≤1.0% and the damp-heat dimensional change rate is required to be ≤1.5%.

[0142] High and low temperature cycling performance: Tested according to GB / T 26689-2024 6.9. The test cycle is: temperature (-30±2)℃, time 24h, equilibration 2h, temperature (55±2)℃, time 24h, equilibration 2h, air as heat transfer medium, the test is carried out for 3 cycles, and visual inspection is performed after taking it out.

[0143] Table 2. Performance test results of polyurethane foam obtained in Examples 1-5 and Comparative Examples 1-2

[0144] As shown in Table 2: Comparative Example 1 uses a commonly used petroleum-based polyether polyol (Class I formulation), with an initial thermal conductivity (0.0203 W / (m·K)) close to the upper limit of the Class I national standard (0.0205 W / (m·K)), and a compressive strength (135 kPa) only slightly higher than the lower limit of the national standard (130 kPa). Furthermore, the raw materials rely on fossil resources, resulting in high carbon emissions. In contrast, Examples 1-3 show significant improvements in thermal insulation performance (initial thermal conductivity reduced by 2-3%), mechanical stability (compressive strength increased by 15-26%), and environmental friendliness (bio-based substitution, 30% reduction in carbon emissions).

[0145] Comparative Example 2 uses existing vegetable oil-based polyols (Class I formulation). Its initial thermal conductivity (0.0204 W / (m·K)) and compressive strength (130 kPa) are both at the critical values ​​of the Class I national standard. Furthermore, the raw materials compete with those used in the food industry, resulting in high costs. In contrast, Examples 1-3, through modification of cashew nut shell liquid (a non-food competing waste resource), not only comprehensively surpass the performance of Comparative Example 2 but also resolve the resource conflict issue of existing bio-based polyols, fully demonstrating the technological superiority and sustainability of the polyol compositions provided in this application in the field of bio-based rigid foam.

[0146] The performance data of Comparative Examples 1-2 (thermal conductivity ≥ 0.0203 W / (m·K), compressive strength ≤ 135 kPa) are significantly different from those of Examples 1-3 (thermal conductivity ≈ 0.0198 W / (m·K), compressive strength ≥ 155 kPa). This application achieves precise control over rigid foam performance by finely adjusting the hydroxyl value (350 / 400 / 420 mg KOH / g), NCO / OH molar ratio (1.10 / 1.11 / 1.12), and cyclopentane content (15 / 16 / 14 parts) of the cashew nut shell liquid-based polyol in the polyol composition. Specifically, the initial thermal conductivity of the polyurethane foam is stabilized at 0.0197~0.0199 W / (m·K), and the compressive strength at 155~170 kPa. This demonstrates that this application achieves a breakthrough in polyurethane foam performance through "precise synthesis of cashew nut shell liquid-based polyol + synergistic optimization of formulation parameters (isocyanate and cyclopentane)".

[0147] In summary, the preparation method of the polyol composition provided in this application results in the following advantages for the final polyurethane foam: Thermal insulation performance is superior to national standards: The initial thermal conductivity of Examples 1-3 is as low as 0.0197-0.0199 W / (m·K), close to the target value of 0.0198 W / (m·K), which is 3-4% lower than the upper limit of Class I national standards (0.0205 W / (m·K)) and 2-3% lower than traditional petroleum-based rigid foam (0.0203 W / (m·K)). This can reduce the average daily power consumption of the refrigerator by 0.3-0.5 kWh, meeting the first-level energy efficiency standard. Stable and reliable mechanical properties: The compressive strength of Examples 1 to 3 reaches 155 to 170 kPa, which is far higher than the Class I national standard requirement (≥130 kPa). It still maintains 145 to 160 kPa in a low temperature environment of -30℃, effectively preventing the refrigerator body from deforming during transportation and use. Overall performance fully meets and exceeds national standards: the apparent core density of Examples 1-3 is 33-35 kg / m³. 3 (Meets the requirement of ≤36kg / m) 3 Requirements: Closed-cell rate 93~95% (higher than ≥90% requirement), water absorption rate 2.0~2.5% (lower than ≤4% requirement), low temperature / damp heat dimensional stability ±0.5~0.8% / ±0.9~1.2% respectively (both better than the national standard upper limit), no deformation, peeling or cracking after high and low temperature cycling, fully meeting the long-term use requirements of refrigerators; It combines environmental friendliness and economic efficiency: the raw material cost of cashew shell liquid polyol is 8,500-9,500 yuan / ton, which is 15-20% lower than that of petroleum-based polyether polyol (11,000-12,000 yuan / ton); the amount of cyclopentane foaming agent used (14-16 parts) is reduced by 15-25% compared with the traditional amount (20 parts), further reducing costs; the bio-based content is ≥60%, and carbon emissions are reduced by more than 30% compared with petroleum-based rigid foam, which complies with environmental regulations; High process adaptability: The synthesis process is simple and does not require modification of existing rigid foam production lines for refrigerators (such as high-pressure foaming machines and mold systems). The polyols are highly compatible with conventional MDI and cyclopentane foaming agents. The polyol compositions, including cashew shell liquid-based polyols, can directly replace existing petroleum-based polyols. The yield rate is ≥95% during large-scale production. The testing items are fully compatible with the factory inspection (appearance, initial thermal conductivity, compressive strength, low-temperature dimensional stability, apparent core density) and type inspection requirements of GB / T26689-2024 Class I.

[0148] The technical solutions provided by the embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A method for preparing a polyol composition, characterized in that, Includes the following steps: Cashew shell liquid, epoxide and Lewis acid catalyst are mixed and subjected to an epoxy ring-opening reaction to obtain epoxidized cashew shell liquid; The epoxidized cashew shell liquid was chemically modified independently using an amination modifier, a thiol modifier, and a phosphorylation modifier to obtain a first cashew shell liquid-based polyol, a second cashew shell liquid-based polyol, and a third cashew shell liquid-based polyol, respectively. The first cashew nut shell liquid-based polyol, the second cashew nut shell liquid-based polyol, and the third cashew nut shell liquid-based polyol are mixed to obtain the polyol composition.

2. The method for preparing the polyol composition according to claim 1, characterized in that, The epoxide is selected from one or more of propylene oxide and epichlorohydrin; The Lewis acid catalyst is selected from one or more of zinc chloride, aluminum chloride, and ferrous chloride; The amount of Lewis acid catalyst added is 0.25% to 0.4% of the mass of the cashew nut shell liquid; The mass ratio of the cashew nut shell liquid to the epoxide is 1:(0.75~0.9). The epoxy ring-opening reaction is carried out at a temperature of 90℃~95℃ for 4h~6h. The epoxy value of the epoxidized cashew shell liquid is 0.32 mol / 100g to 0.45 mol / 100g.

3. The method for preparing the polyol composition according to claim 1, characterized in that, The epoxidized cashew shell liquid includes a first epoxidized cashew shell liquid for preparing the first cashew shell liquid-based polyol, a second epoxidized cashew shell liquid for preparing the second cashew shell liquid-based polyol, and a third epoxidized cashew shell liquid for preparing the third cashew shell liquid-based polyol. The first epoxidized cashew shell liquid has an epoxy value of 0.32 mol / 100g to 0.36 mol / 100g, the second epoxidized cashew shell liquid has an epoxy value of 0.37 mol / 100g to 0.40 mol / 100g, and the third epoxidized cashew shell liquid has an epoxy value of 0.41 mol / 100g to 0.45 mol / 100g.

4. The method for preparing the polyol composition according to claim 3, characterized in that, The epoxidized cashew shell liquid is chemically modified by independently employing an amination modifier, a thiol modifier, and a phosphorylation modifier to obtain a first cashew shell liquid-based polyol, a second cashew shell liquid-based polyol, and a third cashew shell liquid-based polyol, respectively, comprising: The amination modifier and the first epoxidized cashew shell liquid are mixed and subjected to a first microwave heating treatment to obtain the first cashew shell liquid-based polyol. Under nitrogen atmosphere and ultraviolet light irradiation, the second epoxidized cashew shell liquid, the thiol modifier and the photoinitiator are mixed and subjected to a second microwave heating treatment to obtain the second cashew shell liquid-based polyol. The phosphorylation modifier and the third epoxidized cashew shell liquid are mixed and heated to obtain the third cashew shell liquid-based polyol.

5. The method for preparing the polyol composition according to claim 4, characterized in that, The molar ratio of the first epoxidized cashew shell liquid to the amination modifier is 1:(1.15~1.25). The molar ratio of the second epoxidized cashew nut shell liquid, the thiol modifier, and the photoinitiator is 1:(1.8~2.0):(0.005~0.007). The molar ratio of the third epoxidized cashew nut shell liquid to the phosphorylation modifier is 1:(1.15~1.25). The amination modifier is selected from one or more of glycine, diethanolamine, triethanolamine, isopropanolamine, tetraethylenepentamine, and triethylenetetramine; The thiol modifier is selected from one or more of 2-mercaptoethanol, 3-mercaptopropane-1,2-diol, and propane-1-thiol; The photoinitiator is selected from one or more of 2,2-dimethoxy-2-phenylacetophenone, 2,2-dialkyl-2-hydroxyacetophenone, 2-hydroxy-2-methyl-phenylacetophenone, phenylbis-(2,4,6-trimethylbenzoyl)-phosphine oxide, benzophenone, and 2-isopropylthioxanthone; The phosphorylation modifier is selected from phosphoric acid; The microwave power of the first microwave heating treatment is 280W~320W, the temperature is 115℃~125℃, and the time is 2h~2.5h; The wavelength of the ultraviolet light is 365nm~400nm; The microwave power of the second microwave heating treatment is 280W~320W, the temperature is 60℃~65℃, and the time is 24h~30h; The heat treatment is performed at a temperature of 80℃~85℃ for a duration of 6h~6.5h.

6. The method for preparing the polyol composition according to claim 4, characterized in that, The first cashew nutshell liquid-based polyol has a hydroxyl value of 345 mgKOH / g to 355 mgKOH / g, the second cashew nutshell liquid-based polyol has a hydroxyl value of 395 mgKOH / g to 405 mgKOH / g, and the third cashew nutshell liquid-based polyol has a hydroxyl value of 415 mgKOH / g to 425 mgKOH / g; and / or The first cashew nutshell liquid-based polyol has an acid value ≤ 0.08 mgKOH / g, the second cashew nutshell liquid-based polyol has an acid value ≤ 0.08 mgKOH / g, and the third cashew nutshell liquid-based polyol has an acid value ≤ 0.09 mgKOH / g; and / or The viscosities of the first cashew shell liquid-based polyol, the second cashew shell liquid-based polyol, and the third cashew shell liquid-based polyol at 25°C are each independently selected from 15 Pa·s to 30 Pa·s.

7. The method for preparing the polyol composition according to claim 1, characterized in that, Before reacting the cashew nut shell liquid with the epoxide, the process further includes pretreatment of the cashew nut shell liquid, which comprises: sequentially subjecting the cashew nut shell liquid to vacuum dehydration and filtration; wherein... The moisture content of the pretreated cashew shell liquid is ≤0.3%; The cashew nut shell liquid has a cashew phenol content of ≥70%, an acid value of 10 mgKOH / g~15 mgKOH / g, and a moisture content of ≤0.5%. The vacuum degree of the vacuum dehydration process is -0.09 MPa to -0.095 MPa, the temperature is 115 ℃ to 125 ℃, and the time is 2 h to 2.5 h.

8. The method for preparing the polyol composition according to claim 1, characterized in that, After independently using an amination modifier, a thiol modifier, and a phosphorylation modifier to chemically modify the epoxidized cashew shell liquid to obtain a first cashew shell liquid-based polyol, a second cashew shell liquid-based polyol, and a third cashew shell liquid-based polyol, and before mixing one or more of the first cashew shell liquid-based polyol, the method further includes: The first cashew shell liquid-based polyol, the second cashew shell liquid-based polyol, and the third cashew shell liquid-based polyol are each purified independently; the purification includes impurity removal, washing, and vacuum distillation.

9. The method for preparing the polyol composition according to claim 1, characterized in that, By mass, the first cashew nut shell liquid-based polyol in the polyol composition is 0 to 40 parts, the second cashew nut shell liquid-based polyol is 0 to 30 parts, and the third cashew nut shell liquid-based polyol is 0 to 60 parts. Wherein, at least one of the following mass fractions is not zero: the first cashew shell liquid-based polyol, the second cashew shell liquid-based polyol, and the third cashew shell liquid-based polyol.

10. A polyol composition, characterized in that, The polyol composition is obtained by the preparation method of the polyol composition according to any one of claims 1 to 9.

11. A polyurethane composition, characterized in that, The polyurethane composition comprises the polyol composition of claim 10 above.

12. The polyurethane composition of claim 11, characterized in that, By weight, the polyurethane composition comprises 100 parts of the polyol composition, 14 to 17 parts of the foaming agent, and 130 to 155 parts of the isocyanate; The foaming agent includes alkane foaming agents, which include one or more of cyclopentane, isopentane, n-pentane, and cyclohexane. The isocyanate includes polymeric diphenylmethane diisocyanate, wherein the NCO content in the isocyanate is 29.5%~30.5%, and the polymeric diphenylmethane diisocyanate content in the isocyanate is 29.5%~30.5%. The molar ratio of the isocyanate group in the isocyanate to the hydroxyl group in the polyol composition is (1.08~1.12):

1.

13. The polyurethane composition of claim 12, characterized in that, The polyurethane composition further comprises, by weight, 1.1 to 1.5 parts of foam stabilizer, 0.65 to 0.95 parts of catalyst, and 5.8 to 7.2 parts of flame retardant; The foam stabilizer includes an organosilicon surfactant, which includes one or more of Momentive L-580 silicone oil, Dow Corning DC-193 silicone oil, Dow Corning DC-5043 silicone oil, and fluorinated polyglycerol ether-polydimethylsiloxane block copolymer. The catalyst comprises one or more of amine catalysts and organometallic compound catalysts. The amine catalyst comprises one or more of triethylenediamine, N,N-dimethylcyclohexylamine, N,N,N',N'-tetramethylethylenediamine, dimethylethanolamine, N,N-dimethylbenzylamine, and 2,2'-dimorpholine diethyl ether. The organometallic compound catalyst comprises one or more of dibutyltin dilaurate, zinc octanoate, bismuth isooctanoate, and tetrabutyl titanate. The flame retardant includes one or more of phosphorus-based and halogen-based flame retardants. The phosphorus-based flame retardant includes one or more of triphenyl phosphate, diethyl ethyl phosphate, dimethyl methyl phosphate, propyl dimethylphosphonate, dimethyl phosphonate, and triethyl phosphate. The halogen-based flame retardant includes tris(2-chloropropyl) phosphate.

14. A polyurethane foam, characterized in that, The polyurethane foam is obtained by foaming the polyurethane composition according to any one of claims 11 to 13.

15. The polyurethane foam as described in claim 14, characterized in that, The initial thermal conductivity of the polyurethane foam is ≤0.020 W / (m·K), and the compressive strength of the polyurethane foam is ≥150 kPa; and / or The apparent core density of the polyurethane foam is 33 kg / m³. 3 ~36 kg / m 3 Closed-cell rate ≥93%, water absorption rate ≤2.5%, low-temperature dimensional stability ≤0.8%, and damp-heat dimensional stability ≤1.2%.

16. A refrigeration device, characterized in that, The refrigeration equipment includes an insulation layer, which is made of polyurethane foam as described in claim 14 or 15.

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