Rigid polyurethane foam and preparation method thereof
By optimizing the raw material ratio and process flow in polyurethane foam, a rigid polyurethane foam with low thermal conductivity and low density was prepared, which solved the problems of high GWP value of the foaming agent and high thermal conductivity, and achieved more environmentally friendly and efficient Isolation performance.
Patent Information
- Application Number
- CN202411508530.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-28
- Publication Date
- 2024-12-31
AI Technical Summary
The foaming agent in the preparation of existing polyurethane foams has a high GWP value or a high gas phase thermal conductivity, which limits the thermal conductivity and environmental protection of the foam.
Rigid polyurethane foam is prepared by reacting polyether polyols, polyester polyols, catalysts, silicone oils, chemical foaming agents and physical foaming agents in specific proportions, and the process is optimized through nitrogen pressure holding and foaming equipment to form a low thermal conductivity and low density foam.
The foam thermal conductivity coefficient is less than 18.8mw/mk, the core density is less than 28Kg/m3, the ODP value is zero, and the GWP value is less than 5, which meets environmental protection requirements, and reduces the amount and cost of foaming materials, and improves the insulation effect.
Smart Images
Figure CN119219880A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of polyurethane, and in particular to a rigid polyurethane foam and a preparation method thereof. Background Art
[0002] In the construction, transportation, and appliance industries, polyurethane foam is used to insulate structures. As an insulation material, polyurethane foam acts as a seamless and maintenance-free air barrier that provides many benefits, such as preventing moisture infiltration and mold growth and reducing energy use, such as lowering heating and / or cooling costs.
[0003] Polyurethane foam is formed by the exothermic reaction of the resin combination and isocyanate component comprising a blowing agent, i.e. a polyurethane system. The resin combination comprises a mixture of polyols, a blowing agent, a catalyst and other components, and is usually supplied as a first component. The isocyanate component reacted with the resin combination is usually supplied as a second component. The resin combination comprises various components, such as reactants, catalysts, and blowing agents, which can react over time and reduce the shelf life of the resin combination. In addition, the resin combination must show rheological properties that contribute to the resin combination and the effective and efficient application of the reaction mixture comprising the resin combination and the isocyanate component. For this reason, select resin combination and the isocyanate component to optimize the storage stability of the resin combination and the application properties and the performance attributes of the polyurethane foam products for specific purposes (such as isolation).
[0004] Traditionally, physical blowing agents, such as chlorofluorocarbon blowing agents (CFCs) and hydrochlorofluorocarbon blowing agents (HCFCs), are used not only to foam polyurethanes, but also to help control the exothermic reaction between the resin composition and the isocyanate. Due to environmental issues, CFCs are phased out to HCFCs. Recently, new regulations have legally mandated the phase-out of HCFCs to the use of non-ozone depleting physical blowing agents, such as hydrofluoroolefin blowing agents (HFOs). The phase-out of CFCs and HCFCs and the subsequent use of HFOs have created challenges in the shelf life of resin compositions including HFOs, as well as in controlling the exothermic reaction between the resin composition and the isocyanate and efficiently forming polyurethane foams having the properties required for specific uses (such as isolation). The blowing agents used in the related art either have a high GWP value, which limits their use, or have a high gas phase thermal conductivity, which is not conducive to further reducing the thermal conductivity of the foam. Summary of the invention
[0005] The present application provides a rigid polyurethane foam and a preparation method thereof, in order to solve the problem that the foaming agent used in the current related technology either has a high GWP value, which limits its use, or has a high gas phase thermal conductivity, which is not conducive to further reducing the thermal conductivity of the foam.
[0006] In a first aspect, the present application provides a rigid polyurethane foam, which is prepared by reacting the following raw materials in parts by weight:
[0007] 95-100 parts of polyether polyol; 5-10 parts of polyester polyol; 2.2-2.8 parts of catalyst; 2.5-3.2 parts of silicone oil; 2.0-2.8 parts of chemical foaming agent; 15-19 parts of physical foaming agent; 145-165 parts of polyisocyanate; wherein the weight ratio of the polyisocyanate to other raw materials is 1.15-1.30.
[0008] In some possible implementations, the polyether polyol is composed of 20 to 28 parts of sucrose polyether polyol, 15 to 20 parts of sorbitol polyether polyol, 32 to 40 parts of toluene diamine polyether polyol and 15 to 20 parts of glycerol polyether polyol, and the polyester polyol is phthalic anhydride polyester polyol. The sucrose polyether polyol has a viscosity of 4500 to 8500 mPa.s at 25°C; the sorbitol polyether polyol has a viscosity of 4000 to 6000 mPa.s at 25°C; the toluene diamine polyether polyol has a viscosity of 4000 to 7500 mPa.s at 25°C; the glycerol polyether polyol has a viscosity of 300 to 600 mPa.s at 25°C; and the phthalic anhydride polyester polyol has a viscosity of 1000 to 2000 mPa.s at 25°C.
[0009] In some possible implementations, the catalyst is selected from a tertiary amine catalyst, a composite catalyst consisting of N,N,N',N",N"-pentamethyldiethylenetriamine and tris(dimethylaminopropyl)hexahydrotriazine.
[0010] In some possible implementations, the silicone oil is polyether siloxane silicone oil.
[0011] In some possible implementations, the physical foaming agent is composed of 12 to 15 parts of cyclopentane or cycloisopentane and 2.5 to 3.5 parts of 3,3,3-trifluoropropylene.
[0012] In some possible implementations, the cycloisopentane is composed of cyclopentane and isopentane in a ratio of (7-9):(3-1).
[0013] In a second aspect, the present application provides a method for preparing a rigid polyurethane foam, the method comprising:
[0014] The polyether polyol, polyester polyol, catalyst, silicone oil and deionized water are mixed and aged in a reaction kettle according to a preset proportion to prepare a white material;
[0015] The white material and the foaming agent are mixed by a premixing device, and the obtained mixed white material is subjected to the first nitrogen pressure maintenance in the mixing tank;
[0016] The mixed white material and polyisocyanate are transported to the white material tank and black material tank of the foaming equipment through pipelines for the second nitrogen pressure maintenance;
[0017] The black material and the mixed white material are injected into the foaming mold through the foaming equipment. The material liquid undergoes milky whitening, foaming, cross-linking and complete solidification to form a rigid polyurethane foam.
[0018] In some possible implementations, the mixed white material is pressurized with nitrogen in a mixing tank, and the pressure is 0.2-0.5 MPa.
[0019] In some possible implementations, the temperature of the raw materials in the material tank is controlled at 16-20°C, and the holding pressure is 0.2-0.5MPa.
[0020] In some possible implementations, the curing time is 100 to 120 seconds.
[0021] From the above content, it can be known that the present application provides a rigid polyurethane foam and a preparation method thereof, wherein the rigid polyurethane foam is prepared by reacting the following raw materials in parts by weight: 95-100 parts of polyether polyol; 5-10 parts of polyester polyol; 2.2-2.8 parts of catalyst; 2.5-3.2 parts of silicone oil; 2.0-2.8 parts of chemical foaming agent; 15-18 parts of physical foaming agent; 145-165 parts of polyisocyanate; wherein the weight ratio of the polyisocyanate to other raw materials is 1.15-1.30. The rigid polyurethane foam prepared by the present invention has the advantages of good fluidity, low thermal conductivity, low foaming density, etc. The thermal conductivity of the foam is less than 18.8mw / mk, and the core density is less than 28Kg / m 3 The rigid polyurethane foam prepared by the present invention is more environmentally friendly, has an ODP value of zero, a GWP value of less than 5, and can be selected according to different foaming agents to meet the restriction requirements for HFCs foaming agents such as 245fa and 134a. The rigid polyurethane foam prepared by the present invention has a low foam density and is evenly distributed, and the amount of foaming material is reduced by 3-6%, and the foaming cost is better; in addition, the foaming curing time is short and the thermal insulation effect is better. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] In order to more clearly illustrate the technical solution of the present application, the drawings required for use in the embodiments are briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.
[0023] Figure 1 This is a flow chart of the method for preparing rigid polyurethane foam provided in an embodiment of the present application. DETAILED DESCRIPTION
[0024] The following embodiments are described in detail, and examples thereof are shown in the accompanying drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The implementations described in the following embodiments do not represent all implementations consistent with the present application. They are only examples of systems and methods consistent with some aspects of the present application as detailed in the claims.
[0025] In the construction, transportation, and appliance industries, polyurethane foam is used to insulate structures. As an insulation material, polyurethane foam acts as a seamless and maintenance-free air barrier that provides many benefits, such as preventing moisture infiltration and mold growth and reducing energy use, such as lowering heating and / or cooling costs.
[0026] Polyurethane foam is formed by the exothermic reaction of the resin combination and isocyanate component comprising a blowing agent, i.e. a polyurethane system. The resin combination comprises a mixture of polyols, a blowing agent, a catalyst and other components, and is usually supplied as a first component. The isocyanate component reacted with the resin combination is usually supplied as a second component. The resin combination comprises various components, such as reactants, catalysts, and blowing agents, which can react over time and reduce the shelf life of the resin combination. In addition, the resin combination must show rheological properties that contribute to the resin combination and the effective and efficient application of the reaction mixture comprising the resin combination and the isocyanate component. For this reason, select resin combination and the isocyanate component to optimize the storage stability of the resin combination and the application properties and the performance attributes of the polyurethane foam products for specific purposes (such as isolation).
[0027] Traditionally, physical blowing agents, such as chlorofluorocarbon blowing agents (CFCs) and hydrochlorofluorocarbon blowing agents (HCFCs), are used not only to foam polyurethanes, but also to help control the exothermic reaction between the resin composition and the isocyanate. Due to environmental issues, CFCs are phased out to HCFCs. Recently, new regulations have legally mandated the phase-out of HCFCs to the use of non-ozone depleting physical blowing agents, such as hydrofluoroolefin blowing agents (HFOs). The phase-out of CFCs and HCFCs and the subsequent use of HFOs have created challenges in the shelf life of resin compositions including HFOs, as well as in controlling the exothermic reaction between the resin composition and the isocyanate and efficiently forming polyurethane foams having the properties required for specific uses (such as isolation). The blowing agents used in the related art either have a high GWP value, which limits their use, or have a high gas phase thermal conductivity, which is not conducive to further reducing the thermal conductivity of the foam.
[0028] Based on this, the present application provides a rigid polyurethane foam and a preparation method thereof, in which high-viscosity black material is applied to refrigerator foaming, and the foam strength is high. While ensuring the foam strength, the foam density is further reduced; the high fluidity of the low-boiling point foaming agent is combined with the high-viscosity black material to develop a suitable foaming material formula, to make up for the problem of insufficient fluidity of the high-viscosity black material, and to ensure that the foam prepared by the present invention has good density distribution and thermal insulation performance.
[0029] In some embodiments, Figure 1 As shown, the present application provides a method for preparing a rigid polyurethane foam, the method comprising:
[0030] The polyether polyol, polyester polyol, catalyst, silicone oil and deionized water are mixed and aged in a reaction kettle according to a preset proportion to prepare a white material;
[0031] The white material and the foaming agent are mixed by a premixing device, and the obtained mixed white material is subjected to the first nitrogen pressure maintenance in the mixing tank;
[0032] The mixed white material and polyisocyanate are transported to the white material tank and black material tank of the foaming equipment through pipelines for the second nitrogen pressure maintenance;
[0033] The black material and the mixed white material are injected into the foaming mold through the foaming equipment. The material liquid undergoes milky whitening, foaming, cross-linking and complete solidification to form a rigid polyurethane foam.
[0034] In some embodiments, the mixed white material is pressurized with nitrogen in a mixing tank, and the pressure is 0.2-0.5 MPa.
[0035] In some embodiments, the temperature of the raw materials in the material tank is controlled at 16-20° C., and the holding pressure is 0.2-0.5 MPa.
[0036] In some embodiments, the curing time is 100 to 120 seconds.
[0037] In some embodiments, the present application also provides a rigid polyurethane foam prepared by the preparation method provided in the above embodiments, wherein the rigid polyurethane foam is prepared by reacting the following raw materials in parts by weight:
[0038] 95-100 parts of polyether polyol; 5-10 parts of polyester polyol; 2.2-2.8 parts of catalyst; 2.5-3.2 parts of silicone oil; 2.0-2.8 parts of chemical foaming agent; 15-19 parts of physical foaming agent; 145-165 parts of polyisocyanate; wherein the weight ratio of the polyisocyanate to other raw materials is 1.15-1.30.
[0039] The sucrose polyether polyol has a viscosity of 4500-8500 mPa.s at 25°C; the sorbitol polyether polyol has a viscosity of 4000-6000 mPa.s at 25°C; the toluene diamine polyether polyol has a viscosity of 4000-7500 mPa.s at 25°C; the glycerol polyether polyol has a viscosity of 300-600 mPa.s at 25°C; and the phthalic anhydride polyester polyol has a viscosity of 1000-2000 mPa.s at 25°C.
[0040] In some embodiments, the polyether polyol is composed of 20-28 parts of sucrose polyether polyol, 15-20 parts of sorbitol polyether polyol, 32-40 parts of toluene diamine polyether polyol and 15-20 parts of glycerol polyether polyol, and the polyester polyol is phthalic anhydride polyester polyol.
[0041] In some embodiments, the catalyst is selected from a tertiary amine catalyst, a composite catalyst consisting of N,N,N',N",N"-pentamethyldiethylenetriamine and tris(dimethylaminopropyl)hexahydrotriazine.
[0042] Wherein, the polyisocyanate is selected from Wanhua PM2010, BASF M20S, Covestro 44V20L, etc.
[0043] In some embodiments, the silicone oil is polyether siloxane silicone oil, and the silicone oil is selected from one or more of B8534 and B84201 of Evonik, L6863 of Momentive, etc.
[0044] In some embodiments, the physical foaming agent is composed of 12 to 15 parts of cyclopentane or cycloisopentane and 2.5 to 3.5 parts of 3,3,3-trifluoropropylene. The chemical foaming agent is deionized water.
[0045] In some embodiments, the cycloisopentane is composed of cyclopentane and isopentane in a ratio of (7-9):(3-1).
[0046] The rigid polyurethane foam prepared by the invention has the advantages of good fluidity, low thermal conductivity, low foaming density, etc. The thermal conductivity of the foam is less than 18.8mw / m·k, and the core density is less than 28Kg / m 3 The rigid polyurethane foam prepared by the present invention is more environmentally friendly, has an ODP value of zero, a GWP value of less than 5, and can be selected according to different foaming agents to meet the restriction requirements for HFCs foaming agents such as 245fa and 134a. The rigid polyurethane foam prepared according to the present invention has a low foam density and is evenly distributed, and the amount of foaming material is reduced by 3-6%, and the foaming cost is better; in addition, the foaming curing time is short and the thermal insulation effect is better.
[0047] Example 1
[0048] Step 1, preparation of white material: 25 parts of sucrose polyether polyol, 18 parts of sorbitol polyether polyol, 35 parts of phenylenediamine polyether polyol, 17 parts of glycerol polyether polyol, 5 parts of phthalic anhydride polyester polyol, 2.8 parts of catalyst, 2.65 parts of silicone oil and 2.3 parts of deionized water are mixed and matured in a reactor to prepare white material.
[0049] Step 2, preparation of mixed white material: white material, 14.5 parts of foaming agent cyclopentane and 3 parts of 3,3,3-trifluoropropylene are mixed through premixing equipment, and the obtained mixed white material is pressurized with nitrogen in a mixing tank with a pressure of 0.2-0.5MPa.
[0050] Step 3: Raw material transportation and temperature adjustment: Mix the white material and 156.6 parts of polyisocyanate and transport them to the white material tank and black material tank of the foaming equipment through pipelines respectively. The raw material temperature of the material tank is controlled at 16-20°C and the pressure is maintained at 0.2-0.5MPa.
[0051] Step 4, foaming: inject the polyisocyanate (black material) and the mixed white material into the foaming mold through the foaming equipment, and the material liquid is milky, foamed, cross-linked and completely cured to form a rigid polyurethane foam.
[0052] Example 2
[0053] Step 1, preparation of white material: 25 parts of sucrose polyether polyol, 18 parts of sorbitol polyether polyol, 35 parts of phenylenediamine polyether polyol, 17 parts of glycerol polyether polyol, 5 parts of phthalic anhydride polyester polyol, 2.8 parts of catalyst, 2.65 parts of silicone oil and 2.3 parts of deionized water are mixed and matured in a reactor to prepare white material.
[0054] Step 2, preparation of mixed white material: white material, 14.8 parts of foaming agent cyclopentane and 3.5 parts of 3,3,3-trifluoropropylene are mixed through premixing equipment, and the obtained mixed white material is pressurized with nitrogen in a mixing tank with a pressure of 0.2-0.5MPa.
[0055] Step 3: Raw material transportation and temperature adjustment: Mix the white material and 157.6 parts of polyisocyanate and transport them to the white material tank and black material tank of the foaming equipment through pipelines respectively. The raw material temperature of the material tank is controlled at 16-20°C and the pressure is maintained at 0.2-0.5MPa.
[0056] Step 4, foaming: inject the polyisocyanate (black material) and the mixed white material into the foaming mold through the foaming equipment, and the material liquid is milky, foamed, cross-linked and completely cured to form a rigid polyurethane foam.
[0057] Example 3
[0058] Step 1, preparation of white material: 25 parts of sucrose polyether polyol, 18 parts of sorbitol polyether polyol, 35 parts of phenylenediamine polyether polyol, 17 parts of glycerol polyether polyol, 5 parts of phthalic anhydride polyester polyol, 2.8 parts of catalyst, 2.65 parts of silicone oil and 2.3 parts of deionized water are mixed and matured in a reactor to prepare white material.
[0059] Step 2, preparation of mixed white material: white material, 12.3 parts of foaming agent cyclopentane, 2.2 parts of isopentane, and 3 parts of 3,3,3-trifluoropropylene are mixed through premixing equipment, and the obtained mixed white material is pressurized with nitrogen in a mixing tank with a pressure of 0.2-0.5MPa.
[0060] Step 3: Raw material transportation and temperature adjustment: Mix the white material and 156.6 parts of polyisocyanate and transport them to the white material tank and black material tank of the foaming equipment through pipelines respectively. The raw material temperature of the material tank is controlled at 16-20°C and the pressure is maintained at 0.2-0.5MPa.
[0061] Step 4, foaming: inject the polyisocyanate (black material) and the mixed white material into the foaming mold through the foaming equipment, and the material liquid is milky, foamed, cross-linked and completely cured to form a rigid polyurethane foam.
[0062] Comparative Example 1
[0063] Step 1, preparation of white material: 30 parts of sucrose polyether polyol, 15 parts of sorbitol polyether polyol, 35 parts of phenylenediamine polyether polyol, 20 parts of glycerol polyether polyol, 2.6 parts of catalyst, 2.5 parts of silicone oil and 2.26 parts of deionized water are mixed and matured in a reactor to prepare white material.
[0064] Step 2, preparation of mixed white material: white material, 14 parts of blowing agent cyclopentane and 2 parts of 134a are mixed by premixing equipment, and the obtained mixed white material is pressurized with nitrogen in a mixing tank with a pressure of 0.2-0.5MPa.
[0065] Step 3: Raw material transportation and temperature adjustment: Mix the white material and 154.2 parts of polyisocyanate and transport them to the white material tank and black material tank of the foaming equipment through pipelines respectively. The raw material temperature in the material tank is controlled at 16-20°C and the pressure is maintained at 0.2-0.5MPa.
[0066] Step 4, foaming: inject the polyisocyanate (black material) and the mixed white material into the foaming mold through the foaming equipment, and the material liquid is milky, foamed, cross-linked and completely cured to form a rigid polyurethane foam.
[0067] Comparative Example 2
[0068] Step 1, preparation of white material: 30 parts of sucrose polyether polyol, 15 parts of sorbitol polyether polyol, 35 parts of phenylenediamine polyether polyol, 20 parts of glycerol polyether polyol, 2.6 parts of catalyst, 2.5 parts of silicone oil and 2.26 parts of deionized water are mixed and matured in a reactor to prepare white material.
[0069] Step 2, preparation of mixed white material: white material, 11.9 parts of blowing agent cyclopentane, 2.1 parts of isopentane, and 2 parts of 134a are mixed through premixing equipment, and the obtained mixed white material is pressurized with nitrogen in a mixing tank with a pressure of 0.2-0.5 MPa.
[0070] Step 3: Raw material transportation and temperature adjustment: Mix the white material and 154.2 parts of polyisocyanate and transport them to the white material tank and black material tank of the foaming equipment through pipelines respectively. The raw material temperature in the material tank is controlled at 16-20°C and the pressure is maintained at 0.2-0.5MPa.
[0071] Step 4, foaming: inject the polyisocyanate (black material) and the mixed white material into the foaming mold through the foaming equipment, and the material liquid is milky, foamed, cross-linked and completely cured to form a rigid polyurethane foam.
[0072] In the above specific embodiments, different foaming material formulas are developed according to different proportions of blowing agents such as cyclopentane, isopentane, 134a and 3,3,3-trifluoropropylene, corresponding to Comparative Example 1, Comparative Example 2, Example 1, Example 2 and Example 3, respectively. The amounts of each component of the raw materials are shown in Table 1.
[0073] Table 1
[0074] Process parameters and performance unit Comparative Example 1 Comparative Example 2 Example 1 Example 2 Example 3 Sucrose polyether polyol Weight 30 30 25 25 25 Sorbitol polyether polyol Weight 15 15 18 18 18 Phenylenediamine polyether polyol Weight 35 35 35 35 35 Glycerol polyether polyol Weight 20 20 17 17 17 Phthalic Anhydride Polyester Polyol Weight - - 5 5 5 Silicone oil Weight 2.5 2.5 2.65 2.65 2.65 catalyst Weight 2.6 2.6 2.8 2.8 2.8 water Weight 2.26 2.26 2.3 2.3 2.3 Cyclopentane Weight 14 11.9 14.5 14.8 12.3 Isopentane Weight / 2.1 / / 2.2 134a Weight 2 2 / / / 3,3,3-Trifluoropropene Weight / / 3 3.5 3 PM-2010 Weight 154.2 154.2 156.6 157.6 156.6
[0075] After foaming, the foam is cooled and matured at room temperature for a certain period of time and then dissected for relevant performance tests. The thermal conductivity, compressive strength and low-temperature dimensional stability tests are carried out in accordance with the GB / T26689-2011 rigid polyurethane foam plastic standard for refrigerators and freezers.
[0076] The comparative test results of the foaming test of Examples 1-3 and Comparative Examples 1-2 in a BCD-351 refrigerator are shown in Table 2.
[0077] Table 2
[0078]
[0079]
[0080] It can be seen from the above table that, compared with Comparative Example 1, the amount of foaming material used in Examples 1-2 is reduced by 4% and 6%, respectively, and the curing time is reduced by 30s. Compared with Comparative Example 2, the amount of foaming material used in Example 3 is reduced by 4.1%, and the curing time is reduced by 30s. The foam adhesion of Examples 1-3 is good, and the bubbles on the foam surface are basically equivalent to those in the Comparative Example. Although the compression strength is slightly reduced, the foam size is stable. In addition, the high and low temperature tests of the embodiment boxes are all qualified, and the thermal conductivity of the foam is slightly reduced between Examples 1-2 and Comparative Example 1, and between Example 3 and Comparative Example 2.
[0081] The rigid polyurethane foam prepared by the present invention has more delicate and uniform foam, good foam fluidity, excellent foam thermal conductivity, and has significant advantages in reducing foaming density cost, improving foaming efficiency, etc.; by adjusting the foaming raw material formula, the refrigerator prepared according to the raw material formula and foaming process of the present invention has an average core density of 27-28Kg / m3 and a curing time of 120s. Although the foam strength of the polyurethane foam layer is reduced, the foam cells are more delicate and round, the dimensional stability is equivalent, and the shrinkage deformation of the box meets the requirements; in addition, the refrigerator prepared by the present invention is more environmentally friendly, with an ODP value of 0 and a GWP value of less than 5, which can meet the environmental protection requirements of various countries for foaming agents.
[0082] It can be seen from the above embodiments that the present application provides a rigid polyurethane foam and a preparation method thereof, wherein the rigid polyurethane foam is prepared by reacting the following raw materials by weight: 95-100 parts of polyether polyol; 5-10 parts of polyester polyol; 2.2-2.8 parts of catalyst; 2.5-3.2 parts of silicone oil; 2.0-2.8 parts of chemical foaming agent; 15-18 parts of physical foaming agent; 145-165 parts of polyisocyanate; wherein the weight ratio of the polyisocyanate to the weight of other raw materials is 1.15-1.30. The rigid polyurethane foam prepared by the present invention has the advantages of good fluidity, low thermal conductivity, low foaming density, etc. The thermal conductivity of the foam is less than 18.8mw / mk, and the core density is less than 28Kg / m3. The rigid polyurethane foam prepared by the present invention is more environmentally friendly, with an ODP value of zero and a GWP value of less than 5. It can be selected according to different foaming agents to meet the restriction requirements for HFCs foaming agents such as 245fa and 134a. The rigid polyurethane foam prepared by the invention has low foam density and uniform distribution, and the amount of foaming material is reduced by 3-6%, so the foaming cost is better; in addition, the foaming curing time is short and the heat preservation effect is better.
[0083] Similar parts between the embodiments provided in this application can be referenced to each other. The specific implementation methods provided above are only a few examples under the general concept of this application and do not constitute a limitation on the protection scope of this application. For those skilled in the art, any other implementation methods expanded based on the scheme of this application without creative work belong to the protection scope of this application.
Claims
1. A rigid polyurethane foam, characterized in that: The rigid polyurethane foam is prepared by reacting the following raw materials in parts by weight: 95-100 parts of polyether polyol, 5-10 parts of polyester polyol, 2.2-2.8 parts of catalyst, 2.5-3.2 parts of silicone oil, 2.0-2.8 parts of chemical foaming agent, 15-19 parts of physical foaming agent, 145-165 parts of polyisocyanate; wherein the weight ratio of the polyisocyanate to other raw materials is 1.15-1.
30.
2. The rigid polyurethane foam according to claim 1, characterized in that The polyether polyol is composed of 20 to 28 parts of sucrose polyether polyol, 15 to 20 parts of sorbitol polyether polyol, 32 to 40 parts of toluene diamine polyether polyol and 15 to 20 parts of glycerol polyether polyol, and the polyester polyol is phthalic anhydride polyester polyol.
3. The rigid polyurethane foam according to claim 2, characterized in that The sucrose polyether polyol has a viscosity of 4500-8500 mPa.s at 25°C; the sorbitol polyether polyol has a viscosity of 4000-6000 mPa.s at 25°C; the toluene diamine polyether polyol has a viscosity of 4000-7500 mPa.s at 25°C; the glycerol polyether polyol has a viscosity of 300-600 mPa.s at 25°C; and the phthalic anhydride polyester polyol has a viscosity of 1000-2000 mPa.s at 25°C.
4. The rigid polyurethane foam according to claim 1, characterized in that The catalyst is selected from tertiary amine catalysts, and is a composite catalyst composed of N,N,N',N",N"-pentamethyldiethylenetriamine and tris(dimethylaminopropyl)hexahydrotriazine.
5. The rigid polyurethane foam according to claim 1, characterized in that The silicone oil is polyether siloxane silicone oil.
6. The rigid polyurethane foam according to claim 1, characterized in that The physical foaming agent is composed of 12 to 15 parts of cyclopentane or cycloisopentane and 2.5 to 3.5 parts of 3,3,3-trifluoropropylene.
7. The rigid polyurethane foam according to claim 6, characterized in that The cycloisopentane is composed of cyclopentane and isopentane in a ratio of (7-9): (3-1).
8. A method for preparing a rigid polyurethane foam, the method comprising: The polyether polyol, polyester polyol, catalyst, silicone oil and deionized water are mixed and aged in a reaction kettle according to a preset proportion to prepare a white material; The white material and the foaming agent are mixed by a premixing device, and the obtained mixed white material is subjected to the first nitrogen pressure maintenance in the mixing tank; The mixed white material and polyisocyanate are transported to the white material tank and black material tank of the foaming equipment through pipelines for the second nitrogen pressure maintenance; The black material and the mixed white material are injected into the foaming mold through the foaming equipment. The material liquid undergoes milky whitening, foaming, cross-linking and complete solidification to form a rigid polyurethane foam.
9. The method for preparing a rigid polyurethane foam according to claim 8, characterized in that: The mixed white material is pressurized with nitrogen in the mixing tank, and the pressure is 0.2-0.5MPa.
10. The method for preparing rigid polyurethane foam according to claim 8, characterized in that: The temperature of raw materials in the material tank is controlled at 16-20℃, and the holding pressure is 0.2-0.5MPa.