Preparation method of carbon dioxide assisted water foaming PIR material

Abstract

The invention provides a preparation method of a carbon dioxide-assisted water-foamed PIR material, which comprises the following steps: S1, filling polyester polyol and polyether polyol into a reaction kettle, adding a foam stabilizer, a chemical foaming agent, a foaming catalyst, a flame retardant and a chemical foaming agent, and then injecting liquid carbon dioxide to obtain a component A; and S2, taking isocyanate as a component B, mixing the component A and the component B according to a weight ratio of 1: (1.7-2), and carrying out foaming molding by a high-pressure foaming machine. According to the invention, carbon dioxide is adopted to assist water foaming, water is taken as a main chemical foaming agent, liquid carbon dioxide is introduced as a physical foaming agent for synergistic foaming, and the liquid carbon dioxide can generate a large number of uniform bubble nucleation points at the moment of mixing, so that a finer and more uniform closed cell structure can be formed; this is the basis for obtaining excellent thermal insulation and mechanical properties.

Description

Technical Field

[0001] This invention relates to the field of PIR material technology, specifically to a method for preparing PIR materials using carbon dioxide-assisted water foaming. Background Technology

[0002] PIR (Polyisocyanurate Foam), also known as polyisocyanurate, is a foam material made by reacting isocyanate with polyether through a catalyst. Its physical properties and fire resistance are superior to ordinary polyurethane. It is an ideal organic low-temperature insulation material with low thermal conductivity, lightweight shock resistance, and strong adaptability. It is widely used in thermal insulation in oil refineries, chemical plants, ethylene plants, fertilizer plants, cold storage facilities, and the construction industry.

[0003] PIR foaming processes typically employ either chemical or physical foaming. Chemical foaming usually uses water as the blowing agent. Water reacts with excess isocyanate to produce carbon dioxide gas and polyurea. The generated carbon dioxide forms bubble nuclei in the system and expands with the reaction, ultimately forming the foam's cellular structure. The amines produced in the reaction further react with isocyanate to form polyurea bonds, which constitute part of the foam's polymer backbone. Physical foaming typically uses pentane as the blowing agent. Pentane is a liquid at room temperature and pressure. During the foaming process, it does not undergo a chemical reaction but relies on the heat of reaction generated when the polyurethane raw materials are mixed to rapidly evaporate and vaporize, causing a dramatic expansion in volume, thus "blowing" the liquid mixture into foam plastic. However, the above foaming processes suffer from drawbacks such as low foam dimensional stability and unstable performance during aging. Summary of the Invention

[0004] To address the above problems, this invention provides a method for preparing a carbon dioxide-assisted water foaming PIR material, comprising the following steps: Step S1: Load polyester polyol and polyether polyol into a reaction vessel, add foam stabilizer, chemical foaming agent, foaming catalyst, flame retardant, and chemical foaming agent, and then inject liquid carbon dioxide to obtain component A. Step S2: Use isocyanate as component B, mix component A and component B in a weight ratio of 1:(1.7-2), and then use a high-pressure foaming machine to mix and foam them into shape.

[0005] Preferably, in step S1, the liquid carbon dioxide injection pressure is 5-15 MPa, and the material temperature is controlled at 20-40°C. More preferably, in step S1, the liquid carbon dioxide injection pressure is 7.5-15 MPa, and the material temperature is controlled at 32-40°C. The critical pressure of carbon dioxide is 7.3 MPa, and the critical temperature is 31°C. When the pressure > 7.3 MPa and the temperature is greater than the critical temperature, carbon dioxide is in a supercritical state, possessing a density similar to that of a liquid and diffusivity similar to that of a gas, and can instantly form a homogeneous solution with polyols, resulting in extremely high mixing quality.

[0006] Preferably, in step S1, by weight, component A includes: polyester polyol, 20-40 parts; polyether polyol, 10-30 parts; foaming catalyst, 1-3 parts; foam stabilizer, 1-3 parts; chemical foaming agent, 1-3 parts; and liquid carbon dioxide, 3-10 parts.

[0007] Polyester polyols exhibit high reactivity with isocyanates, forming polyurethane ester bonds. Polyether polyols are used to adjust system viscosity, improve raw material compatibility and flowability, and reduce foam brittleness. Foaming catalysts are used to precisely control the balance between the foaming and gelation reactions, ensuring good foam rise and stability. Foam stabilizers stabilize the cell structure, preventing bubble formation and collapse, and are crucial additives for achieving high closed-cell rates.

[0008] Preferably, the chemical foaming agent is deionized water.

[0009] Preferably, the foam stabilizer is a polysiloxane-polyether copolymer. The siloxane segments (hydrophobic) can strongly reduce surface tension, while the polyether segments (hydrophilic) can ensure good dispersion in the polyol / water system, resulting in uniform bubble nucleation and the formation of an elastic film on the bubble wall.

[0010] Preferably, the foaming catalyst is a trimerizing catalyst or an organometallic salt catalyst.

[0011] The trimer catalyst can be PC-41, which can strongly catalyze the trimerization of isocyanate to form isocyanurate rings; the organometallic salt catalyst can be, for example, potassium acetate, which can promote the rapid formation of polymer networks, stabilize cells, and prevent foam from collapsing after rising.

[0012] Preferably, step S2 further includes preparing component C, which comprises an epoxy compound and a polyetheramine in a weight ratio of (5-8):1; then, components A, B and C in a weight ratio of 1:(1.7-2):(1-1.5) are mixed and foamed in a high-pressure foaming machine to form the final product.

[0013] Epoxy compounds react with CO2 within the pores to form cyclic carbonates. The functional groups of these cyclic carbonates undergo secondary crosslinking with polyetheramines to form urethane bonds, thus covalently bonding the "fixed" CO2 fragments to the polymer backbone. Additionally, some polyetheramines react with isocyanates to form polyurea bonds, which exhibit higher heat resistance compared to polyurethane bonds, thereby enhancing the crosslinking density and rigidity of the entire polymer network. The epoxy compound can be epoxidized soybean oil or glycidyl ethers (such as neopentyl glycol diglycidyl ether). Epoxidized soybean oil is inexpensive, has high functionality (approximately 3-4 epoxy groups per molecule), and is more prone to crosslinking. Polyetheramine D-230 with a molecular weight of approximately 230 can be used. If polyetheramine D-230 reacts too quickly, a secondary amine with slightly lower reactivity (such as polyetheramine D-400) can be used instead.

[0014] Preferably, component C further includes tetrabutylammonium bromide, with the weight ratio of tetrabutylammonium bromide to polyetheramine being (0.5-1):1. Tetrabutylammonium bromide can catalyze the reaction of epoxides with CO2 under mild conditions. Preferably, in step S2, the mixing pressure is 10-20 MPa and the material temperature is controlled at 20-30°C.

[0015] Preferably, step S2 further includes: after foaming and molding, placing it in an oven for curing treatment, with a curing temperature of 70-80℃ and a curing time of 2-4 hours.

[0016] The purpose of aging at 70-80°C is: (1) to complete the chemical fixation of carbon dioxide: under the action of a catalyst, epoxides (such as epoxidized soybean oil) undergo a cycloaddition reaction with carbon dioxide in the pores to generate solid cyclic carbonates. (2) to drive deep secondary crosslinking: the cyclic carbonates generated in the previous step will undergo a ring-opening reaction with the polyetheramine in the formulation to form new and strong urethane bonds, which strongly chemically anchor the fixed carbon dioxide fragments to the entire polymer network, greatly increasing the crosslinking density.

[0017] Compared with the prior art, the beneficial effects of the present invention are: This invention employs carbon dioxide-assisted water foaming, using water as the primary chemical foaming agent and introducing liquid carbon dioxide as a physical foaming agent for synergistic foaming. The liquid carbon dioxide generates numerous uniform bubble nucleation points upon mixing, contributing to a finer and more uniform closed-cell structure, which is fundamental to achieving excellent thermal insulation and mechanical properties. While maintaining foam strength, the use of carbon dioxide effectively reduces the overall density of the foam, resulting in significant raw material cost savings. Carbon dioxide can partially replace water and help form more uniform closed cells. By optimizing the formulation, foams with lower initial thermal conductivity and more stable long-term aging performance can be prepared. Detailed Implementation

[0018] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] Example 1

[0020] The method for preparing PIR materials for carbon dioxide-assisted water foaming provided in this embodiment includes the following steps: Step S1: Load polyester polyol and polyether polyol into a reaction vessel, add foam stabilizer, chemical foaming agent, foaming catalyst, flame retardant, and chemical foaming agent, then inject liquid carbon dioxide at a pressure of 6 MPa and a temperature of 15°C; wherein, component A includes 30 parts polyether polyol (hydroxyl value of about 450 mgKOH / g), 20 parts polyester polyol (hydroxyl value of about 300 mgKOH / g), 2.2 parts deionized water, 2 parts polysiloxane-polyether copolymer (Momentive CA1180), 1.5 parts trimerizing catalyst PC-41, and 6 parts liquid carbon dioxide.

[0021] Step S2: Isocyanate is used as component B. Components A and B are mixed and foamed in a weight ratio of 1:1.8 using a high-pressure foaming machine. The mixing pressure is 13 MPa, and the material temperature is controlled at 25°C. After foaming and molding, the mixture is placed in an oven for curing at 75°C for 3 hours.

[0022] The prepared material was subjected to pore size and stability tests. The results showed that the average pore size was approximately 145 μm and the closed-porosity was greater than 93%. After stabilization testing at 70°C for 48 h, the volume change was less than 1.0%.

[0023] Example 2

[0024] The method for preparing PIR materials for carbon dioxide-assisted water foaming provided in this embodiment includes the following steps: Step S1: Load polyester polyol and polyether polyol into a reaction vessel, add foam stabilizer, chemical foaming agent, foaming catalyst, flame retardant, and chemical foaming agent, and then inject liquid carbon dioxide at a pressure of 5 MPa and a temperature of 20°C; wherein, component A includes 20 parts polyether polyol (hydroxyl value of about 450 mgKOH / g), 10 parts polyester polyol (hydroxyl value of about 300 mgKOH / g), 1 part deionized water, 1 part polysiloxane-polyether copolymer (Momentive CA1180), 1 part trimerizing catalyst PC-41, and 3 parts liquid carbon dioxide.

[0025] Step S2: Using isocyanate as component B, mix components A and B in a weight ratio of 1:1.7 using a high-pressure foaming machine. The mixing pressure is 10 MPa, and the material temperature is controlled at 20°C. After foaming and molding, place the mixture in an oven for curing at 70°C for 2 hours.

[0026] The prepared material was subjected to pore size and stability tests. The results showed that the average pore size was approximately 137 μm and the closed-porosity was greater than 94%. After stabilization testing at 70°C for 48 h, the volume change was less than 1.0%.

[0027] Example 3

[0028] The method for preparing PIR materials for carbon dioxide-assisted water foaming provided in this embodiment includes the following steps: Step S1: Load polyester polyol and polyether polyol into a reaction vessel, add foam stabilizer, chemical foaming agent, foaming catalyst, flame retardant, and chemical foaming agent, and then inject liquid carbon dioxide at a pressure of 15 MPa and a temperature of 40°C; wherein, component A includes 40 parts polyether polyol (hydroxyl value of about 450 mgKOH / g), 30 parts polyester polyol (hydroxyl value of about 300 mgKOH / g), 3 parts deionized water, 3 parts polysiloxane-polyether copolymer (Momentive CA1180), 3 parts trimer catalyst PC-41, and 10 parts liquid carbon dioxide.

[0029] Step S2: Isocyanate is used as component B. Components A and B are mixed in a 1:2 weight ratio and foamed using a high-pressure foaming machine. The mixing pressure is 20 MPa, and the material temperature is controlled at 30°C. After foaming and molding, the mixture is placed in an oven for curing at 80°C for 4 hours. The prepared material was subjected to pore size and stability tests. The results showed that the average pore size was approximately 131 μm and the closed-porosity was greater than 95%. After stabilization testing at 70°C for 48 h, the volume change was less than 1.0%.

[0030] Example 4

[0031] The method for preparing PIR materials for carbon dioxide-assisted water foaming provided in this embodiment includes the following steps: Step S1: Load polyester polyol and polyether polyol into a reaction vessel, add foam stabilizer, chemical foaming agent, foaming catalyst, flame retardant, and chemical foaming agent, then inject liquid carbon dioxide at a pressure of 6 MPa and a temperature of 15°C; wherein, component A includes 30 parts polyether polyol (hydroxyl value of about 450 mgKOH / g), 20 parts polyester polyol (hydroxyl value of about 300 mgKOH / g), 2.2 parts deionized water, 2 parts polysiloxane-polyether copolymer (Momentive CA1180), 1.5 parts trimerizing catalyst PC-41, and 6 parts liquid carbon dioxide.

[0032] Step S2: Mix and foam components A, B, and C in a weight ratio of 1:1.7:1 using a high-pressure foaming machine at a mixing pressure of 13 MPa and a material temperature controlled at 25°C. Then, place the mixture in an oven for curing at 75°C for 3 hours. Component C includes epoxidized soybean oil and polyetheramine D-230 in a weight ratio of 5:1.

[0033] The prepared material was subjected to pore size and stability tests. The results showed that the average pore size was approximately 125 μm and the closed-porosity was greater than 96%. After stabilization testing at 70°C for 48 h, the volume change was less than 1.0%.

[0034] Example 5

[0035] The method for preparing PIR materials for carbon dioxide-assisted water foaming provided in this embodiment includes the following steps: Step S1: Load polyester polyol and polyether polyol into a reaction vessel, add foam stabilizer, chemical foaming agent, foaming catalyst, flame retardant, and chemical foaming agent, then inject liquid carbon dioxide at a pressure of 6 MPa and a temperature of 15°C; wherein, component A includes 30 parts polyether polyol (hydroxyl value of about 450 mgKOH / g), 20 parts polyester polyol (hydroxyl value of about 300 mgKOH / g), 2.2 parts deionized water, 2 parts polysiloxane-polyether copolymer (Momentive CA1180), 1.5 parts trimerizing catalyst PC-41, and 6 parts liquid carbon dioxide.

[0036] Step S2: Mix and foam components A, B, and C in a weight ratio of 1:2:1.5 using a high-pressure foaming machine at a mixing pressure of 13 MPa and a material temperature controlled at 25°C. Then, place the mixture in an oven for curing at 75°C for 3 hours. Component C includes epoxidized soybean oil and polyetheramine D-230 in a weight ratio of 8:1.

[0037] The prepared material was subjected to pore size and stability tests. The results showed that the average pore size was approximately 120 μm and the closed-porosity was greater than 96%. After stabilization testing at 70°C for 48 h, the volume change was less than 1.0%.

[0038] Example 6

[0039] The method for preparing PIR materials for carbon dioxide-assisted water foaming provided in this embodiment includes the following steps: Step S1: Load polyester polyol and polyether polyol into a reaction vessel, add foam stabilizer, chemical foaming agent, foaming catalyst, flame retardant, and chemical foaming agent, then inject liquid carbon dioxide at a pressure of 6 MPa and a temperature of 15°C; wherein, component A includes 30 parts polyether polyol (hydroxyl value of about 450 mgKOH / g), 20 parts polyester polyol (hydroxyl value of about 300 mgKOH / g), 2.2 parts deionized water, 2 parts polysiloxane-polyether copolymer (Momentive CA1180), 1.5 parts trimerizing catalyst PC-41, and 6 parts liquid carbon dioxide.

[0040] Step S2: Components A, B, and C, in a weight ratio of 1:1.9:1.2, are mixed and foamed in a high-pressure foaming machine at a mixing pressure of 13 MPa and a material temperature controlled at 25°C. The mixture is then placed in an oven for curing at 75°C for 3 hours. Component C includes epoxidized soybean oil, polyetheramine D-230, and tetrabutylammonium bromide in a weight ratio of 5:1:0.5.

[0041] The prepared material was subjected to pore size and stability tests. The results showed that the average pore size was approximately 128 μm and the closed-porosity was greater than 97%. After stabilization testing at 70°C for 48 h, the volume change was less than 1.0%.

[0042] Example 7

[0043] The method for preparing PIR materials for carbon dioxide-assisted water foaming provided in this embodiment includes the following steps: Step S1: Load polyester polyol and polyether polyol into a reaction vessel, add foam stabilizer, chemical foaming agent, foaming catalyst, flame retardant, and chemical foaming agent, then inject liquid carbon dioxide at a pressure of 6 MPa and a temperature of 15°C; wherein, component A includes 30 parts polyether polyol (hydroxyl value of about 450 mgKOH / g), 20 parts polyester polyol (hydroxyl value of about 300 mgKOH / g), 2.2 parts deionized water, 2 parts polysiloxane-polyether copolymer (Momentive CA1180), 1.5 parts trimerizing catalyst PC-41, and 6 parts liquid carbon dioxide.

[0044] Step S2: Components A, B, and C, in a weight ratio of 1:1.9:1.2, are mixed and foamed in a high-pressure foaming machine at a mixing pressure of 13 MPa and a material temperature controlled at 25°C. The mixture is then placed in an oven for curing at 75°C for 3 hours. Component C includes epoxidized soybean oil, polyetheramine D-230, and tetrabutylammonium bromide in a weight ratio of 8:1:1.

[0045] The prepared material was subjected to pore size and stability tests. The results showed that the average pore size was approximately 122 μm and the closed-porosity was greater than 97%. After stabilization testing at 70°C for 48 h, the volume change was less than 1.0%.

[0046] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to the embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a PIR material for carbon dioxide-assisted water foaming, characterized in that, Includes the following steps: Step S1: Load polyester polyol and polyether polyol into a reaction vessel, add foam stabilizer, chemical foaming agent and foaming catalyst, and then inject liquid carbon dioxide to obtain component A. Step S2: Use isocyanate as component B, mix component A and component B in a weight ratio of 1:(1.7-2), and then use a high-pressure foaming machine to mix and foam them into shape.

2. The method for preparing PIR material for carbon dioxide-assisted water foaming according to claim 1, characterized in that, In step S1, the liquid carbon dioxide injection pressure is 5-15 MPa, and the material temperature is controlled at 20-40°C.

3. The method for preparing PIR material for carbon dioxide-assisted water foaming according to claim 1, characterized in that, In step S1, by weight, component A includes: polyester polyol, 20-40 parts; polyether polyol, 10-30 parts; foaming catalyst, 1-3 parts; foam stabilizer, 1-3 parts; chemical foaming agent, 1-3 parts; and liquid carbon dioxide, 3-10 parts.

4. The method for preparing PIR material for carbon dioxide-assisted water foaming according to any one of claims 1-3, characterized in that, The chemical foaming agent is deionized water.

5. The method for preparing PIR material for carbon dioxide-assisted water foaming according to any one of claims 1-3, characterized in that, The foam stabilizer is a polysiloxane-polyether copolymer.

6. The method for preparing PIR material for carbon dioxide-assisted water foaming according to any one of claims 1-3, characterized in that, The foaming catalyst is a trimerizing catalyst or an organometallic salt catalyst.

7. The method for preparing PIR material for carbon dioxide-assisted water foaming according to claim 1, characterized in that, Step S2 also includes the preparation of component C, which comprises an epoxy compound and a polyetheramine in a weight ratio of (5-8):1; then components A, B and C in a weight ratio of 1:(1.7-2):(1-1.5) are mixed and foamed in a high-pressure foaming machine to form the final product.

8. The method for preparing PIR material for carbon dioxide-assisted water foaming according to claim 7, characterized in that, Component C also includes tetrabutylammonium bromide, with a weight ratio of tetrabutylammonium bromide to polyetheramine of (0.5-1):

1.

9. The method for preparing PIR material for carbon dioxide-assisted water foaming according to claim 1, characterized in that, In step S2, the mixing pressure is 10-20 MPa and the material temperature is controlled at 20-30°C.

10. The method for preparing PIR material for carbon dioxide-assisted water foaming according to claim 1, characterized in that, Step S2 also includes: after foaming and molding, placing it in an oven for curing treatment, with a curing temperature of 70-80℃ and a curing time of 2-4 hours.