A cold-insulating plastic foam and a method for producing the same

Abstract

The application discloses a cold storage and heat preservation plastic foam and a preparation method thereof. The combined material formula comprises a boric acid polyether polyol and a high-hydroxyl-value o-toluidine polyether polyol. The boric acid polyether polyol has a characteristic of a triangular stable structure of boron atoms, and can improve the strength and dimensional stability of a plastic product and delay the attenuation of the strength and dimensional stability of the plastic product in application. The boric acid polyether polyol contains a part of insoluble B=O structure, which is easy to precipitate in the early stage of the reaction of the combined material with isocyanate, forms stable nucleation points, and through the synergistic effect of the high-hydroxyl-value o-toluidine polyether polyol, the cross-linking of product foam fibers is enhanced, the bubbles are inhibited and the bubbles are made more delicate, and the thermal conductivity of the product is reduced. The rapid cross-linking can reduce the volatilization of a foaming agent and reduce the surface bubbles at the end of product flow.

Description

Technical Field

[0001] This invention belongs to the field of thermal insulation materials, specifically relating to polyurethane foam for cold storage insulation. Background Technology

[0002] Rigid polyurethane (PU) foam is one of the main types of polyurethane synthetic materials. It is a foam plastic made by reacting polyether polyols or polyester polyols with isocyanates to form the polyurethane matrix, and then reacting the isocyanates with water or low-boiling-point chlorofluorocarbon (CFC) blowing agents. It is a type of low-density microporous polymer material with a closed-cell structure and excellent overall performance. As a refrigerator insulation material, it has advantages such as low density, low thermal conductivity, high compressive strength, good adhesion, and ease of processing. Currently, rigid polyurethane foam is widely used not only in the refrigeration industry but also in furniture, construction, packaging, and insulation materials.

[0003] With the country's call for low-carbon, green, and environmentally friendly lifestyles in recent years, refrigerators have become one of the most common household appliances. Reducing refrigerator energy consumption and power consumption is also a way to achieve a low-carbon economy.

[0004] The thermal conductivity of rigid polyurethane foam is mainly composed of solid thermal conductivity, gas thermal conductivity, and thermal radiation, which is also the main theoretical basis for reducing the thermal conductivity of polyurethane foam. Currently, there are three main methods to reduce the thermal conductivity of refrigerator foam: first, reduce the cell size of the polyurethane foam; the smaller the cell size, the lower the efficiency of thermal radiation conduction. Second, reduce the density of the polyurethane foam; the lower the foam density, the lower the solid thermal conductivity. Third, choose a blowing agent with even lower thermal conductivity, such as 245fa or LBA, to replace traditional cyclopentane.

[0005] Due to the high prices of foaming agents such as 245fa and LBA, the cost of foaming materials has increased significantly, impacting the profitability of enterprises. Therefore, manufacturers of compound materials are required to maintain strength while reducing foam density. This necessitates the use of low-boiling-point foaming agents, which utilize the greater internal pressure within the foam at the same temperature to resist shrinkage upon cooling. However, low-boiling-point foaming agents have low boiling points and are easily volatile, often resulting in poor bubble quality on the foam surface.

[0006] Patent CN114316187A discloses rigid polyurethane foam using boric acid polyether polyol as a raw material to achieve better foam strength and flame retardant properties. However, this formulation, designed for building insulation materials, differs significantly from the formulation systems used in household appliance composite materials. Furthermore, its patented implementation scheme is prone to negative effects such as cell rupture, increased cell size, and high thermal conductivity. Refrigerator polyurethane foam, on the other hand, has extremely high requirements for thermal conductivity and cell size, requiring the synergistic effect of multiple polyether polyol raw materials to achieve its intended effect. Therefore, this invention's solution is not suitable for refrigeration insulation plastic foam.

[0007] Patent CN113929851A discloses the synthesis of a high-hydroxyl-value o-toluene diamine polyether polyol and its preparation of polyurethane foam under low vacuum. Utilizing the high viscosity of this polyether polyol, shear breakage during foam flow under low vacuum is reduced, thereby improving foam bubble quality. However, this invention is not suitable for atmospheric pressure foaming. During atmospheric pressure foaming, the high-viscosity polyether has poor flowability, making foam flow difficult and resulting in even worse surface bubble formation.

[0008] Polyurethane foam prepared using low-boiling-point blowing agents is characterized by reduced core density, but suffers from poor long-term dimensional stability and surface bubble formation. Therefore, there is an urgent need for a product that can maintain low thermal conductivity, good foam strength and dimensional stability even at low foam density, and even delay the decline in foam thermal conductivity and strength. This is also a challenge in the upgrading of compound material technology. Summary of the Invention

[0009] To address the problems described above, this invention proposes a refrigerated thermal insulation plastic foam and its preparation method. A novel compounding technology formulation is employed, utilizing the synergistic effect of raw materials to enable the foam product to maintain a low thermal conductivity and good long-term dimensional stability even under low core density conditions.

[0010] The purpose of this invention is to provide a method for preparing the polyether polyol.

[0011] This invention provides a refrigerated thermal insulation plastic foam, prepared from the following raw materials:

[0012] (a) 100 portions of the combined ingredients;

[0013] (b) 20-35 parts of foaming agent;

[0014] (c) 145-170 parts of polyisocyanate.

[0015] The composite material comprises 86.5-93.5 parts of polyol composition, 1.5-4.0 parts of surfactant, 3.5-6.5 parts of composite catalyst, and 1.5-3.0 parts of water.

[0016] Preferably, the polyol composition comprises the following components:

[0017]

[0018]

[0019] Preferably, the boric acid polyether polyol is prepared by adding boric acid to propylene oxide, with a viscosity of 500-2000 mPa·s, a hydroxyl value of 300-500 gKOH / g, and a functionality of 2.2-3.0.

[0020] Preferably, the sucrose polyether polyol is prepared by an addition reaction of sucrose aqueous solution as an initiator, with a sucrose to water mass ratio of 100:2-5, preferably 100:2-3, where water mainly plays the role of dissolving sucrose in the early stage. The polyol has a viscosity of 30,000-50,000 mPa·s, a hydroxyl value of 350-450 gKOH / g, and a functionality of 5.8-7.1.

[0021] Preferably, the sorbitol and glycerol polyether polyol, with sorbitol and glycerol as initiators and a mass ratio of 100:30-50, are prepared by addition reaction with propylene oxide, and have a viscosity of 5000-15000 mPa·s, a hydroxyl value of 320-420 mgKOH / g, and a functionality of 4.5-5.8.

[0022] Preferably, the o-tolyldiamine polyether polyol is prepared by an addition reaction of o-tolyldiamine with propylene oxide, using o-tolyldiamine as an initiator. It has a viscosity of 300,000-500,000 mPa·s, a hydroxyl value of 490-610 mgKOH / g, and a functionality of 3.3-3.9. Its synthesis process is referenced in patent CN113929851A.

[0023] Preferably, the phthalic anhydride polyester polyol is prepared by reacting phthalic anhydride and pyromellitic dianhydride as initiators in a mass ratio of 100:60 with ethylene glycol via an addition reaction. The resulting product has a viscosity of 35,000-50,000 mPa·s, a hydroxyl value of 440-540 mgKOH / g, and a functionality of 2.3-2.8. This polyester polyol exhibits high functionality and excellent compatibility, providing better demolding and curing properties in refrigerator compound formulations.

[0024] The surfactant described in this invention is a silicone surfactant, preferably one or more of silicone oil B8481, silicone oil H36813, silicone oil Y16239, L6620NT and silicone oil B84813.

[0025] The combined catalyst of this invention comprises multiple substances selected from pentamethyldiethylenetriamine, tetramethylhexanediamine, bis-dimethylaminoethyl ether, dimethylbenzylamine, dimethylcyclohexane, triethylenediamine, methylimidazole, potassium formate, potassium acetate, quaternary ammonium salts, and tris(dimethylaminopropyl)hexahydrotriazine. Preferably, the combined catalyst comprises at least one of methyldiethylenetriamine, tetramethylhexanediamine, and bis-dimethylaminoethyl ether; at least one of dimethylbenzylamine, dimethylcyclohexane, triethylenediamine, and methylimidazole; and at least one of potassium formate, potassium acetate, quaternary ammonium salts, and tris(dimethylaminopropyl)hexahydrotriazine.

[0026] The foaming agent described in this invention can be a single foaming agent system or a mixture of foaming agent systems. As a preferred embodiment, the foaming agent contains at least one of 245FA, LBA, CP, and CI, and may also additionally contain at least one of 134a, 152a, GBA, and isobutane.

[0027] The polyisocyanate described in this invention is polymeric MDI, preferably polymeric MDI with an NCO content of 30-32 wt%; more preferably, it is one or more of Wanhua Chemical's PM-200, PM-2010 and PM-400.

[0028] A method for preparing the refrigerated thermal insulation plastic foam according to any one of claims 1-9, comprising the following steps: according to a proportion,

[0029] 1) Mix the polyol combination, surfactant, combined catalyst and water evenly and cool to below 15°C to obtain the combined material;

[0030] 2) Add the foaming agent to the mixture obtained in step 1) and mix thoroughly;

[0031] 3) The product of step 2) and the polyisocyanate are subjected to high-pressure circulation and mixed evenly by flushing at the nozzle of the foaming machine, and then poured into a fixed mold to obtain the refrigerated heat-insulating plastic foam; the high-pressure foaming process in step 3) is performed under the following conditions: material temperature 15-18℃, pressure 100-150 bar; preferably material temperature 17℃, pressure 125 bar; mold temperature 35-50℃, overfill rate 15%-25%, and demolding time 130-300s.

[0032] The method for preparing refrigerated thermal insulation plastic foam according to the present invention includes the following steps: according to the proportion,

[0033] a) Mix the polyol combination, surfactant, combined catalyst and water evenly and cool to below 15°C to obtain the combined material;

[0034] b) Cool the foaming agent with a boiling point above 5°C, such as 245fa, LBA, CP, CI, etc., to below 5°C, add it to the mixture prepared in step 1), and mix it evenly;

[0035] c) If the formulation contains a foaming agent with a boiling point below 5°C, such as 134a, 152a, isobutane, GBA, etc., the product of step 2) needs to be transferred to a mixing tank, and then the foaming agent with a boiling point below 5°C is transported to the mixing tank through a gas pipe. The mixing tank is pressurized with nitrogen to 0.2-0.3MPa and pneumatically stirred for 40-60 minutes. After uniform mixing, the finished product mixture is obtained and transported to the POL tank (combination material tank) of the high-pressure foaming machine through pressure.

[0036] d) The product of step b) or the product of step c) and the polyisocyanate are subjected to high pressure cycling and mixed evenly by flushing at the nozzle of a foaming machine, and then poured into a fixed mold to obtain the refrigerated heat-insulating plastic foam.

[0037] As a preferred embodiment, the high-pressure foaming process in step d) is performed under the following conditions: material temperature 15-18℃, pressure 100-150 bar (gauge pressure); preferably material temperature 17℃, pressure 125 bar (gauge pressure); mold temperature 35-50℃, overfill rate 15%-25%, and demolding time 130-300s.

[0038] The general structural formula of the boric acid polyether polyol of the present invention is as follows:

[0039]

[0040] Wherein: n1-n3 are each an integer not less than 0, and not all of them are 0 at the same time. Preferably, they are each an integer from 1 to 3, such as 1, 2, and 3.

[0041] The method for preparing boric acid polyether polyol according to the present invention includes the following steps: using boric acid as an initiator, and carrying out an addition reaction with propylene oxide.

[0042] The reaction formula is shown below:

[0043]

[0044] As a preferred embodiment, the method for preparing the boric acid polyether polyol includes the following steps: boric acid powder is first reacted with propylene oxide in a solid-gas two-phase reaction at high temperature to produce a small amount of liquid boric acid polyether polyol; the boric acid solid powder is continuously dissolved and then reacted with propylene oxide to obtain the boric acid polyether polyol.

[0045] Preferably, the borate polyether polyol is prepared at a reaction temperature of 85℃-125℃.

[0046] Compared with the prior art, the present invention has the following advantages:

[0047] 1) The borate polyether polyol of the present invention has a triangular structure containing BO bonds, which greatly improves the supporting strength of polyurethane fibers, increases the compressive strength of the foam to over 123 kPa, and reduces the strength decay rate to 4.1% after 180 days.

[0048] 2) The triangular structure of the BO bond of the borate polyether polyol of the present invention has stronger structural stability, thereby improving the long-term dimensional stability of the foam. After aging for 6 months in a high temperature and high humidity environment, the polyurethane foam containing borate polyether polyol has very little change in pressure tank deformation rate.

[0049] 3) The borate polyether polyol and the high-hydroxyl-value o-toluene diamine polyether polyol of the present invention have a synergistic effect. The borate polyether contains uniform suspended particles, which can quickly form blowing agent gas attachment points in the early stage of polyurethane foam reaction, enhancing foam nucleation. The high-hydroxyl-value o-toluene diamine polyether polyol has fast reactivity and high crosslinking degree, and has a good foam stabilizing effect, improving the stability of the cell and reducing the escape weight of low-boiling-point blowing agent, thereby reducing foam skin defects and reducing the number of type A bubbles at the flow end of the L-mold. For formulations containing borate polyether polyol but without high-hydroxyl-value o-toluene diamine polyether polyol, the number of type A bubbles at the flow end of the L-mold increases.

[0050] 4) The borate polyether polyol of this invention has excellent nucleation properties, and combined with the excellent foam-stabilizing properties of the high-hydroxyl-value o-toluene diamine polyether polyol, it reduces foam co-occurrence, resulting in a cell size as low as approximately 50 μm and a thermal conductivity reduced to 16.4 mW / K. Furthermore, it reduces the decay of foam thermal conductivity, with a significant decrease in the 180-day thermal conductivity decay value. This reduces refrigerator energy consumption and improves refrigerator quality.

[0051] 5) The polyester polyol of the present invention contains pyromellitic dianhydride in the initiator, which has a functionality of 4 and a higher degree of crosslinking than conventional polyester polyols, thus better improving the demolding performance and curing performance of foam. Attached Figure Description

[0052] Figure 1 Electron micrograph of Comparative Example 1;

[0053] Figure 2 This is an electron microscope image of Example 3. Detailed Implementation

[0054] The technical solution of the present invention will be further illustrated below through specific embodiments. However, the scope of protection of the present invention is not limited thereto. Within the scope of the technology disclosed in the present invention, any changes or substitutions of the same or similar technical features should be covered within the scope of protection of the present invention.

[0055] The manufacturers and models of the main testing instruments used in the embodiments and comparative examples of this invention are shown in Table 1:

[0056] Table 1. Manufacturers and models of the main testing instruments

[0057] Testing instruments model factory Hydroxyl value tester MB3600 ABB thermal conductivity meter HC-074 EKO Equipment Company Compression Strength Tester 5Kn Proline Zwick / Roell High-pressure foaming machine HK650 Hennecke 3D morphology microscope VHX6000 Keyence

[0058] The sources of the main materials and reagents in the embodiments of this invention are shown in Table 2:

[0059] Table 2. Sources of main materials and reagents in the examples

[0060] Raw material name Relevant parameters Manufacturers Polyether polyol A 425mgKOH / g Rong Wei, Wanhua Chemical (Ningbo) Polyether polyol B 380mgKOH / g Rong Wei, Wanhua Chemical (Ningbo) Polyether polyol C 512mgKOH / g Rong Wei, Wanhua Chemical (Ningbo) Polyester polyol D 484mgKOH / g Rong Wei, Wanhua Chemical (Ningbo) Polyether polyol E1 425mgKOH / g Rong Wei, Wanhua Chemical (Ningbo) Polyether polyol E2 372mgKOH / g Rong Wei, Wanhua Chemical (Ningbo) Polyether polyol F 420mgKOH / g Rong Wei, Wanhua Chemical (Ningbo) Polyether polyol G 365mgKOH / g Rong Wei, Wanhua Chemical (Ningbo) Polyester polyol H 402mgKOH / g Rong Wei, Wanhua Chemical (Ningbo) propylene oxide Purity, ≥99% Wanhua Chemical Silicone surfactants — Momentive, Degussa, Nanjing Demechuang Combined catalysts — Air Products, Solvay, and Vansun Davey 245fa / LBA — Honeywell 134a / 152a — Shandong Yuean n-Butane / Isobutane — Meilong Company Polymer MDI — Wanhua Chemical

[0061] Polyether polyol A: It is prepared by adding sucrose aqueous solution as an initiator, with a sucrose to water weight ratio of 100:2-5, preferably 100:2-3. Water mainly plays the role of dissolving sucrose in the early stage. It is prepared by adding propylene oxide. The viscosity is 33295 mpa.s, the hydroxyl value is 425 mgKOH / g, and the functionality is 6.8.

[0062] Polyether polyol B: Sorbitol and glycerol polyether polyol is prepared by dehydration treatment of sorbitol and glycerol as initiators and addition reaction with propylene oxide before reaction. It has a viscosity of 6411 mPa·s, a hydroxyl value of 380 mgKOH / g, and a functionality of 5.2.

[0063] Polyether polyol C: o-Toluenediamine polyether polyol, prepared by addition reaction of o-TDA with propylene oxide, has a viscosity of 429000 mpa.s, a hydroxyl value of 512 mgKOH / g, and a functionality of 3.7.

[0064] Polyester polyol D is prepared by adding ethylene glycol with phthalic anhydride and pyromellitic dianhydride as initiators in a mass ratio of 100:60. It has a viscosity of 37513 mPa·s, a hydroxyl value of 484 mgKOH / g, and a functionality of 2.6.

[0065] Polyether polyol E1: It is prepared by the addition reaction of boric acid with propylene oxide, with a viscosity of 892 mPa·s, a hydroxyl value of 425 gKOH / g, and a functionality of 2.9.

[0066] Polyether polyol E2: It is prepared by the addition reaction of boric acid with propylene oxide, with a viscosity of 1189 mpa.s, a hydroxyl value of 372 gKOH / g, and a functionality of 2.7.

[0067] Polyether polyol F: prepared by addition reaction of glycerol as an initiator with propylene oxide, with a viscosity of 898 mpa.s, hydroxyl value of 420 gKOH / g, and functionality of 3.0.

[0068] Polyether polyol G: o-Toluenediamine polyether polyol, prepared by addition reaction of o-toluenediamine with propylene oxide as an initiator, has a viscosity of 31183 mpa.s, a hydroxyl value of 365 gKOH / g, and a functionality of 3.7.

[0069] Polyester polyol H: Phthalic anhydride polyester polyol is prepared by the addition reaction of phthalic anhydride with ethylene glycol as an initiator. It has a viscosity of 4411 mpa.s, a hydroxyl value of 402 mgKOH / g, and a functionality of 2.0.

[0070] Example 1

[0071] A method for preparing boric acid polyether polyol, the specific process of which is as follows:

[0072] 1) Weigh 5000g of boric acid into a distillation vessel, heat to 60℃, stir for 4h to remove the water of crystallization adsorbed by boric acid, cool to room temperature, and obtain intermediate product A;

[0073] 2) Take all of the intermediate product A, put it into a stirred tank, add 10000g of propylene oxide, stir at 115-125℃ for 4 hours, cool, and volatilize the excess propylene oxide to obtain intermediate product B.

[0074] 3) Take all intermediate product B, weigh out 13500g, add 405g (3%) of amine alkaline catalyst, stir evenly, and obtain boric acid polyether polyol.

[0075] The synthesized boric acid polyether polyol was tested and found to have a hydroxyl value of 425 mg KOH / g, a viscosity of 892 cps, and a calculated functionality of 2.9.

[0076] Example 2

[0077] A method for preparing boric acid polyether polyol, the specific process of which is as follows:

[0078] 1) Weigh 5000g of boric acid into a distillation vessel, heat to 60℃, stir for 4h to remove the water of crystallization adsorbed by boric acid, cool to room temperature, and obtain intermediate product A;

[0079] 2) Take all of the intermediate product A, put it into a stirred tank, add 10000g of propylene oxide, stir at 85-95℃ for 4 hours, cool, and volatilize the excess propylene oxide to obtain intermediate product B.

[0080] 3) Take all intermediate product B, weigh out 12500g, add 375g (3%) of amine alkaline catalyst, stir evenly, and obtain boric acid polyether polyol.

[0081] The synthesized boric acid polyether polyol was tested and found to have a hydroxyl value of 372 mg KOH / g, a viscosity of 1189 cps, and a calculated functionality of 2.7.

[0082] Example 3

[0083] A type of cold-keeping insulating plastic foam containing boric acid polyether polyol, with the following raw material composition:

[0084] The mass ratio of the composite material, foaming agent 245FA, and polyisocyanate Wanhua PM200 is 100:22:145, specifically:

[0085] The composition of the combined material is as follows: 91.7 parts of polyol composition, 2 parts of surfactant B8481 (Evonik), 3.5 parts of combined catalyst, and 2.8 parts of water.

[0086] The polyol composition comprises the following components: 21.7 parts of sucrose polyether polyol A (hydroxyl value 425 mg KOH / g); 30 parts of sorbitol and glycerol polyether polyol B (hydroxyl value 380 mg KOH / g); 30 parts of o-toluene diamine polyether polyol C (hydroxyl value 512 mg KOH / g); 5 parts of phthalic anhydride polyester polyol D (hydroxyl value 484 mg KOH / g); and 5 parts of boric acid polyol E1 (hydroxyl value 425 mg KOH / g) from Example 1.

[0087] The combined catalyst comprises the following components: the foaming catalyst is bis-dimethylaminoethyl ether, the gel catalyst is dimethylcyclohexylamine, and the trimerizing catalyst is tris(dimethylaminopropyl)hexahydrotriazine, with the ratio of bis-dimethylaminoethyl ether: dimethylcyclohexylamine: tris(dimethylaminopropyl)hexahydrotriazine being 1:3.1:1.2 (mass ratio).

[0088] The preparation method of refrigerated insulation plastic foam is as follows:

[0089] 1) Mix the polyol combination, surfactant, combined catalyst and water evenly and cool to below 15°C to obtain the combined material;

[0090] 2) Cool the LBA to below 5°C, add it to the mixture prepared in step 1), mix it evenly, and convey it to the mixture tank under pressure;

[0091] 3) The product from step 2) and PM200 are subjected to high-pressure circulation and mixed evenly by flushing at the nozzle of the foaming machine, and then poured into a fixed sealed mold to obtain the refrigerated heat-insulating plastic foam.

[0092] The high-pressure foaming process described in step 3) is performed under the following conditions: material temperature 18°C, pressure 125 bar (gauge pressure), mold temperature 38°C, overfill rate 24%, and demolding time 240 s. The ratio of the finished product composite material to the high-pressure foaming polyisocyanate is 1:1.19.

[0093] Example 4

[0094] A type of cold-keeping insulating plastic foam containing boric acid polyether polyol, with the following raw material composition:

[0095] The mass ratio of the composite material, foaming agent 245FA, and polyisocyanate Wanhua PM200 is 100:22:145, specifically:

[0096] The composition of the compound is as follows: 91.7 parts of polyol composition, 2 parts of surfactant B8481 (Evonik), 3.5 parts of combined catalyst, and 2.8 parts of water.

[0097] The polyol composition comprises: 21.7 parts of sucrose polyether polyol A (hydroxyl value 425 mg KOH / g); 20 parts of sorbitol and glycerol polyether polyol B (hydroxyl value 380 mg KOH / g); 20 parts of o-toluene diamine polyether polyol C (hydroxyl value 512 mg KOH / g); 15 parts of phthalic anhydride polyester polyol D (hydroxyl value 484 mg KOH / g); and 15 parts of boric acid polyol E1 (hydroxyl value 425 mg KOH / g) from Example 1.

[0098] The combined catalyst comprises the following components: the foaming catalyst is bis-dimethylaminoethyl ether, the gel catalyst is dimethylcyclohexylamine, and the trimerizing catalyst is tris(dimethylaminopropyl)hexahydrotriazine, with the ratio of bis-dimethylaminoethyl ether: dimethylcyclohexylamine: tris(dimethylaminopropyl)hexahydrotriazine being 1:3.1:1.2 (mass ratio).

[0099] The preparation method of the refrigerated thermal insulation plastic foam is the same as that in Example 3, with a demolding time of 300s.

[0100] Example 5

[0101] A type of cold-keeping insulating plastic foam containing boric acid polyether polyol, with the following raw material composition:

[0102] The mass ratio of the composite material, foaming agent (22 parts 245FA + 2 parts 152a), and polyisocyanate Wanhua PM200 is 100:24:155, specifically:

[0103] The composition of the composite material is as follows: 90 parts of polyol composition, 3 parts of surfactant H36813 (Dongjun), 4.5 parts of composite catalyst, and 2.5 parts of water.

[0104] The polyol composition comprises the following components: 20 parts of sucrose polyether polyol A (hydroxyl value 425 mg KOH / g); 25 parts of sorbitol and glycerol polyether polyol B (hydroxyl value 380 mg KOH / g); 25 parts of o-toluene diamine polyether polyol C (hydroxyl value 512 mg KOH / g); 10 parts of phthalic anhydride polyester polyol D (hydroxyl value 484 mg KOH / g); and 10 parts of boric acid polyol E (hydroxyl value 425 mg KOH / g) from Example 1.

[0105] The combined catalyst comprises the following components: the foaming catalyst is bis-dimethylaminoethyl ether, the gel catalyst is dimethylcyclohexylamine, and the trimerizing catalyst is tris(dimethylaminopropyl)hexahydrotriazine, with the ratio of bis-dimethylaminoethyl ether: dimethylcyclohexylamine: tris(dimethylaminopropyl)hexahydrotriazine being 1:3.1:1.2 (mass ratio).

[0106] The preparation method of refrigerated insulation plastic foam is as follows:

[0107] 1) Mix the polyol combination, surfactant, combined catalyst and water evenly and cool to below 15°C to obtain the combined material;

[0108] 2) Cool the LBA to below 5°C and add it to the mixture prepared in step 1), then mix thoroughly.

[0109] 3) Pour the product from step 2) into a sealed mixing tank, add 152a into the mixing tank under pressure, pressurize with nitrogen to 0.2MPa, pneumatically stir for 50 minutes to mix evenly, and then convey it to the POL tank of the high-pressure foaming machine under pressure.

[0110] 4) The product from step 3) and PM200 are subjected to high-pressure circulation and mixed evenly by flushing at the nozzle of the foaming machine, and then poured into a fixed sealed mold to obtain the refrigerated heat-insulating plastic foam.

[0111] The high-pressure foaming process described in step 4) is performed under the following conditions: material temperature 17°C, pressure 125 bar (gauge pressure), mold temperature 42°C, overfill rate 20%, and demolding time 200 s. The ratio of the finished product composite material to the high-pressure foaming polyisocyanate is 1:1.25.

[0112] Example 6

[0113] A type of cold-keeping insulating plastic foam containing boric acid polyether polyol, with the following raw material composition:

[0114] The mass ratio of the composite material, foaming agent (32 parts LBA + 2 parts n-butane), and polyisocyanate Wanhua PM200 is 100:34:165, specifically as follows:

[0115] The composition of the compound is as follows: 87.7 parts of polyol composition, 4 parts of surfactant L6620NT (Momentive), 6.5 parts of combined catalyst, and 1.8 parts of water.

[0116] The polyol composition comprises the following components: 17.7 parts of sucrose polyether polyol A (hydroxyl value 425 mg KOH / g); 30 parts of sorbitol and glycerol polyether polyol B (hydroxyl value 380 mg KOH / g); 30 parts of o-toluene diamine polyether polyol C (hydroxyl value 512 mg KOH / g); 5 parts of phthalic anhydride polyester polyol D (hydroxyl value 484 mg KOH / g); and 5 parts of boric acid polyol E2 (hydroxyl value 372 mg KOH / g) from Example 2.

[0117] The combined catalyst comprises the following components: the foaming catalyst is bis-dimethylaminoethyl ether, the gel catalyst is dimethylcyclohexylamine, and the trimerizing catalyst is a quaternary ammonium salt, with the ratio of bis-dimethylaminoethyl ether: dimethylcyclohexylamine: quaternary ammonium salt being 1:2.8:1.2 (mass ratio).

[0118] The preparation method of the refrigerated insulation plastic foam is the same as that in Example 5, except that 152a is replaced with n-butane. In step 4), the high-pressure foaming process is carried out under the following conditions: material temperature 15°C, pressure 125 bar (gauge pressure), mold temperature 48°C, overfill rate 20%, and demolding time 130 s. The ratio of the finished composite material to the polyisocyanate in the high-pressure foaming process is 1:1.23.

[0119] Example 7

[0120] A type of cold-keeping insulating plastic foam containing boric acid polyether polyol, with the following raw material composition:

[0121] The mass ratio of the composite material, foaming agent (32 parts LBA + 2 parts n-butane), and polyisocyanate Wanhua PM200 is 100:34:165, specifically as follows:

[0122] The composition of the combined material is as follows: 87.7 parts of polyol composition, 4 parts of surfactant, 6.5 parts of combined catalyst, and 1.8 parts of water.

[0123] The polyol composition comprises the following components: 17.7 parts of sucrose polyether polyol A (hydroxyl value 425 mg KOH / g); 20 parts of sorbitol and glycerol polyether polyol B (hydroxyl value 380 mg KOH / g); 20 parts of o-toluene diamine polyether polyol C (hydroxyl value 512 mg KOH / g); 15 parts of phthalic anhydride polyester polyol D (hydroxyl value 484 mg KOH / g); and 15 parts of boric acid polyol E2 (hydroxyl value 372 mg KOH / g) as described in Example 2.

[0124] The types and contents of surfactants and combined catalysts are the same as in Example 6.

[0125] The preparation method of refrigerated thermal insulation plastic foam is the same as that in Example 6, with a demolding time of 150s.

[0126] The performance parameters of the products in Examples 3-7 are shown in Table 3.

[0127] Table 3 Performance parameters of products in Examples 3-7

[0128]

[0129] Note: Foam density, compressive strength, thermal conductivity, and dimensional stability were all measured according to national standards.

[0130] The foam core density test shall be conducted in accordance with the standard GB / T 6343-2009;

[0131] The thermal conductivity of foam was tested according to standard GB / T 10295-2008.

[0132] The foam compressive strength test shall be conducted in accordance with the standard GB / T 8813-2008;

[0133] Foam dimensional stability testing was conducted in accordance with standard GB / T 8811-2008.

[0134] Surface bubble standard: A+ is defined as diameter ≥ 6cm, A is defined as diameter ≤ 3cm < 6cm, and 1A+ = 2A.

[0135] Comparative Example 1

[0136] Replace borate polyether polyol E1 with glycerol polyether polyol F (hydroxyl value 420 mg KOH / g), and keep other conditions the same as in Example 3.

[0137] Comparative Example 2

[0138] Replace polyester polyol D with polyester polyol H (hydroxyl value 402 mg KOH / g), and keep other conditions the same as in Example 6.

[0139] Comparative Example 3

[0140] Replace o-toluene diamine polyether polyol C with o-toluene diamine polyether polyol G (hydroxyl value 365 mg KOH / g), and keep other conditions the same as in Example 7.

[0141] Comparative Example 4

[0142] Replace borate polyether polyol E2 with polyether polyol B (hydroxyl value 380 mg KOH / g), and keep other conditions the same as in Example 7.

[0143] The performance parameters of the products in Comparative Examples 1-4 are shown in Table 4.

[0144] Table 4 Performance parameters of products in Comparative Examples 1-4

[0145]

Claims

1. A refrigerated thermal insulation plastic foam, prepared from the following raw materials: (a) 100 portions of the combined ingredients; (b) 20-35 parts of foaming agent; (c) 145-170 parts of polyisocyanate; in, The composite material comprises 86.5-93.5 parts of polyol composition, 1.5-4.0 parts of surfactant, 3.5-6.5 parts of composite catalyst, and 1.5-3.0 parts of water; The polyol composition comprises the following components: 5-20 parts of borate polyether polyol; 10-30 parts of sucrose polyether polyol; 10-30 parts of o-toluene diamine polyether polyol; 15-40 parts of sorbitol and glycerol polyether polyol; Phthalic anhydride polyester polyol 5-20 parts; The general structural formula of the boric acid polyether polyol is as follows: Wherein: n1-n3 are each an independent integer not less than 0, and not all of them are 0 at the same time; viscosity is 500-2000 mPa·s; hydroxyl value is 300-500 gKOH / g; and functionality is 2.2-3.

0. The o-toluenediamine polyether polyol is prepared by adding o-toluenediamine to propylene oxide as an initiator. It has a viscosity of 300,000-500,000 mPa·s, a hydroxyl value of 490-610 mgKOH / g, and a functionality of 3.3-3.

9. The phthalic anhydride polyester polyol is prepared by reacting phthalic anhydride and pyromellitic dianhydride as initiators in a mass ratio of 100:60 with ethylene glycol. It has a viscosity of 35,000-50,000 mPa·s, a hydroxyl value of 440-540 mgKOH / g, and a functionality of 2.3-2.

8.

2. The refrigerated insulation foam according to claim 1, characterized in that, The n1-n3 are each an independent integer from 1 to 3.

3. The refrigerated insulation foam according to claim 1, characterized in that, The polyol composition comprises the following components: 5-15 parts of borate polyether polyol; 15-25 parts of sucrose polyether polyol; 15-30 parts of o-toluene diamine polyether polyol; 20-30 parts of sorbitol and glyceryl polyether polyol; Phthalic anhydride polyester polyol 5-15 parts.

4. The refrigerated insulation foam according to claim 1, characterized in that, The sucrose polyether polyol is prepared by an addition reaction with propylene oxide, using sucrose aqueous solution as the initiator, with a sucrose to water mass ratio of 100:2-5, where water plays a role in the initial dissolution of sucrose. The viscosity is 30000-50000 mPa·s, the hydroxyl value is 350-450 gKOH / g, and the functionality is 5.8-7.

1.

5. The refrigerated insulation foam according to claim 4, characterized in that, The mass ratio of sucrose to water is 100:2-3.

6. The refrigerated insulation foam according to claim 1, characterized in that, The sorbitol and glycerol polyether polyol, with sorbitol and glycerol as initiators and a mass ratio of 100:30-50, is prepared by addition reaction with propylene oxide. The viscosity is 5000-15000 mPa·s, the hydroxyl value is 320-420 mgKOH / g, and the functionality is 4.5-5.

8.

7. The refrigerated insulation foam according to claim 1, characterized in that, The foaming agent contains at least one of 245FA, LBA, CP, and CI.

8. The refrigerated insulation foam according to claim 7, characterized in that, The foaming agent also contains at least one of 134a, 152a, GBA, and isobutane.

9. A method for preparing the refrigerated thermal insulation plastic foam according to any one of claims 1-8, comprising the following steps: According to proportion, 1) Mix the polyol combination, surfactant, combined catalyst and water evenly and cool to below 15°C to obtain the combined material; 2) Add the foaming agent to the mixture obtained in step 1) and mix thoroughly; 3) The product of step 2) and the polyisocyanate are subjected to high pressure circulation and mixed evenly by flushing at the nozzle of the foaming machine, and then poured into a fixed mold to obtain the refrigerated heat-insulating plastic foam; the high-pressure foaming process in step 3) is carried out under the following conditions: material temperature 15-18℃, pressure 100-150 bar; mold temperature 35-50℃, overfill rate 15%-25%, and demolding time 130-300s.

10. The method according to claim 9, characterized in that, The material temperature is 17°C and the pressure is gauge pressure 125 bar.

Images