Open-cell polyurethane rigid foam and method for producing the same

Abstract

The application relates to the technical field of polyurethane materials, and discloses open-cell polyurethane rigid foam and a preparation method thereof, wherein the raw materials comprise the following components in parts by weight: 100 parts of polyol, 0.5-5 parts of a catalyst, 0.5-4 parts of water, 5-40 parts of a foaming agent, 0.5-3 parts of a surfactant, 0.5-3 parts of an open-cell agent and 150-160 parts of isocyanate; the polyol comprises low-hydroxyl-value polyether polyol and high-functionality polyether polyol; and the low-hydroxyl-value polyether polyol has a hydroxyl value of less than or equal to 56 mg / g KOH. Through the technical scheme, the problem that the open-cell rate of the polyurethane rigid foam is low due to high initial skeleton strength in the prior art is solved.

Description

Technical Field

[0001] This invention relates to the field of polyurethane materials technology, specifically to an open-cell rigid polyurethane foam and its preparation method. Background Technology

[0002] Rigid polyurethane foam is generally a closed-cell structure, characterized by high strength, light weight, and excellent thermal insulation properties, making it widely used in refrigerators, freezers, solar energy systems, cold storage facilities, and pipeline insulation. However, when rigid polyurethane foam is used in the patching of offshore oil and gas pipelines, it needs to be modified to an open-cell structure.

[0003] Currently, opening agents or silicone oils are typically added during the preparation of rigid polyurethane foam to achieve open-cell structure. However, rigid polyurethane foam usually uses high-functionality polyethers. High-functionality polyethers are rigid, highly functional, and have a high hydroxyl content, resulting in high foam strength in the early stages of foaming. The expansion of the foaming gas is insufficient to break through the bubble walls, easily forming a closed-cell structure during the foaming process. Although opening agents are used, they cannot fundamentally reduce the strength of the foam skeleton in the early stages of foaming, making it difficult to obtain rigid polyurethane foam with a high open-cell ratio. Summary of the Invention

[0004] This invention proposes an open-cell rigid polyurethane foam and its preparation method, which solves the problem of low open-cell rate of rigid polyurethane foam caused by high initial skeleton strength in related technologies.

[0005] The technical solution of the present invention is as follows: An open-cell rigid polyurethane foam comprises the following components by weight: 100 parts polyol, 0.5-5 parts catalyst, 0.5-4 parts water, 5-40 parts blowing agent, 0.5-3 parts surfactant, 0.5-3 parts opening agent, and 150-160 parts isocyanate; wherein the polyol includes low hydroxyl value polyether polyol and high functionality polyether polyol; the hydroxyl value of the low hydroxyl value polyether polyol is ≤56mg / gKOH.

[0006] As a further technical solution, the hydroxyl value of the low hydroxyl value polyether polyol is 50-56 mg / g KOH.

[0007] As a further technical solution, the polyol is composed of the following weight percentages: 5-30% low hydroxyl value polyether polyol and 70-95% high functionality polyether polyol.

[0008] As a further technical solution, the functionality of the low hydroxyl value polyether polyol is 2 ≤ functionality ≤ 3.

[0009] As a further technical solution, the hydroxyl value of the high-functionality polyether polyol is ≥300mg / gKOH; the functionality is ≥4.

[0010] As a further technical solution, the hydroxyl value of the high-functionality polyether polyol is 450-500 mg / g KOH.

[0011] As a further technical solution, the catalyst includes one or more of N,N-dimethylcyclohexylamine, N,N-dimethylbenzylamine, triethylenediamine, triethanolamine, dimethylethanolamine, triethylamine, bis(2-methylamino)ethyl ether, di-n-butyltin dilaurate, stannous octoate, bismuth isooctanoate, lead isooctanoate, lead naphthenate, tetrabutyl titanate, and tetraisopropyl titanate.

[0012] As a further technical solution, the physical foaming agent includes one or more of n-pentane, cyclopentane, isopentane, dichlorofluoroethane, pentafluoropropane, and trans-1,3,3,3-tetrafluoropropylene.

[0013] As a further technical solution, the surfactant is silicone oil.

[0014] This invention also includes a method for preparing open-cell rigid polyurethane foam, comprising the following steps: S1. Weigh the raw materials and set aside. S2. After mixing polyol, catalyst, water, foaming agent, surfactant, and cell opener, a mixture is obtained; S3. Add isocyanate to the mixture and mix to foam, thus obtaining open-cell rigid polyurethane foam.

[0015] The working principle and beneficial effects of this invention are as follows: 1. This invention introduces low-hydroxyl polyether polyols into rigid polyurethane foam, which reduces the strength of the foam in the early stage of foaming, allowing the gas to expand and break through the bubble wall during foaming, naturally forming an open-cell structure, significantly improving the open-cell ratio, and the resulting rigid polyurethane foam still has high strength.

[0016] 2. By limiting the mass ratio of low-hydroxyl-value polyether polyols and high-functionality polyether polyols in the polyols, the open-cell ratio and compressive strength of rigid polyurethane foam can be further improved in this invention. Detailed Implementation

[0017] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. 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 of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0018] In the following examples and comparative examples, 220 polyether, 330N polyether, and 8345 polyether were all purchased from Shandong Yinuowei New Material Co., Ltd.; N,N-dimethylcyclohexylamine, N,N-dimethylbenzylamine, triethylenediamine, and foaming agent 245fa were all purchased from Shanghai Xinrui Chemical Technology Co., Ltd.; silicone oil 8803 and cell opener M-9901 were both purchased from Jiangsu Meiside Co., Ltd.; PM200 polymeric MDI was purchased from Yantai Wanhua; polyether 2045, with a hydroxyl value of 29, was purchased from Ningbo Hongyi Chemical Co., Ltd.; and polyether polyol IV6630, with a hydroxyl value of 550, was purchased from Jining Huakai Resin Co., Ltd.

[0019] Example 1 S1. Mix 20 parts of 220 polyether, 80 parts of polyether polyol 8345, 0.3 parts of N,N-dimethylcyclohexylamine, 1.2 parts of N,N-dimethylbenzylamine, 0.6 parts of triethylenediamine, 1.5 parts of water, 30 parts of foaming agent 245fa, 2 parts of silicone oil 8803, and 1 part of cell opener to obtain a mixture; wherein the 220 polyether has a hydroxyl value of 56 and a functionality of 2, and the polyether polyol 8345 has a functionality of 5.5 and a hydroxyl value of 450; S2. After mixing the mixture with 150 parts of PM200 polymeric MDI, the mixture is foamed through a high-pressure gun head to obtain open-cell rigid polyurethane foam; wherein the pressure of the gun head is 10 MPa.

[0020] Example 2 S1. Mix 30 parts of 220 polyether, 70 parts of polyether polyol 8345, 0.3 parts of N,N-dimethylcyclohexylamine, 1.2 parts of N,N-dimethylbenzylamine, 0.6 parts of triethylenediamine, 1.5 parts of water, 30 parts of foaming agent 245fa, 2 parts of silicone oil 8803, and 1 part of cell opener to obtain a mixture; wherein the 220 polyether has a hydroxyl value of 56 and a functionality of 2, and the polyether polyol 8345 has a functionality of 5.5 and a hydroxyl value of 450; S2. After mixing the mixture with 150 parts of PM200 polymeric MDI, the mixture is foamed through a high-pressure gun head to obtain open-cell rigid polyurethane foam; wherein the pressure of the gun head is 10 MPa.

[0021] Example 3 S1. Mix 15 parts of 330N polyether, 85 parts of polyether polyol 8345, 0.3 parts of N,N-dimethylcyclohexylamine, 1.2 parts of N,N-dimethylbenzylamine, 0.6 parts of triethylenediamine, 1.5 parts of water, 30 parts of foaming agent 245fa, 2 parts of silicone oil 8803, and 1 part of cell opener to obtain a mixture; wherein the 330N polyether has a hydroxyl value of 33 and a functionality of 3; the polyether polyol 8345 has a functionality of 5.5 and a hydroxyl value of 450; S2. After mixing the mixture with 150 parts of PM200 polymeric MDI, the mixture is foamed through a high-pressure gun head to obtain open-cell rigid polyurethane foam; wherein the pressure of the gun head is 10 MPa.

[0022] Example 4 S1. Mix 5 parts of 330N polyether, 95 parts of polyether polyol 8345, 0.3 parts of N,N-dimethylcyclohexylamine, 1.2 parts of N,N-dimethylbenzylamine, 0.6 parts of triethylenediamine, 1.5 parts of water, 30 parts of foaming agent 245fa, 2 parts of silicone oil 8803, and 1 part of cell opener to obtain a mixture; wherein the 330N polyether has a hydroxyl value of 33 and a functionality of 3; the polyether polyol 8345 has a functionality of 5.5 and a hydroxyl value of 450; S2. After mixing the mixture with 150 parts of PM200 polymeric MDI, the mixture is foamed through a high-pressure gun head to obtain open-cell rigid polyurethane foam; wherein the pressure of the gun head is 10 MPa.

[0023] Example 5 S1. Mix 5 parts of 220 polyether, 95 parts of polyether polyol 8345, 0.5 parts of N,N-dimethylcyclohexylamine, 0.5 parts of water, 5 parts of foaming agent 245fa, 0.5 parts of silicone oil 8803, and 0.5 parts of cell opener to obtain a mixture; wherein the 220 polyether has a hydroxyl value of 56 and a functionality of 2, and the polyether polyol 8345 has a functionality of 5.5 and a hydroxyl value of 450; S2. After mixing the mixture with 160 parts of PM200 polymeric MDI, the mixture is foamed through a high-pressure gun head to obtain open-cell rigid polyurethane foam; wherein the pressure of the gun head is 10 MPa.

[0024] Example 6 S1. Mix 30 parts of 220 polyether, 70 parts of polyether polyol 8345, 5 parts of N,N-dimethylcyclohexylamine, 4 parts of water, 40 parts of foaming agent 245fa, 3 parts of silicone oil 8803, and 3 parts of cell opener to obtain a mixture; wherein the hydroxyl value of 220 polyether is 56 and the functionality is 2, and the functionality of polyether polyol 8345 is 5.5 and the hydroxyl value is 450; S2. After mixing the mixture with 160 parts of PM200 polymeric MDI, the mixture is foamed through a high-pressure gun head to obtain open-cell rigid polyurethane foam; wherein the pressure of the gun head is 10 MPa.

[0025] Example 7 Compared with Example 1, Example 7 differs in that it contains 5 parts of 220 polyether and 95 parts of 8345 polyether polyol.

[0026] Example 8 Compared to Example 1, Example 8 replaces 220 polyether with an equal amount of polyether 2045, otherwise it is the same as Example 1.

[0027] Example 9 Compared to Example 1, Example 9 replaces polyether polyol 8345 with an equal amount of polyether polyol IV6630, otherwise it is the same as Example 1.

[0028] Comparative Example 1 S1. Mix 100 parts of polyether polyol 8345, 0.3 parts of N,N-dimethylcyclohexylamine, 1.2 parts of N,N-dimethylbenzylamine, 0.6 parts of triethylenediamine, 1.5 parts of water, 30 parts of foaming agent 245fa, 2 parts of silicone oil 8803, and 1 part of cell opener to obtain a mixture; wherein the functionality of polyether polyol 8345 is 5.5 and the hydroxyl value is 450; S2. Add 150 parts of PM200 polymeric MDI to the mixture and foam to obtain open-cell rigid polyurethane foam.

[0029] Test case The free bubble density, compressive strength and open cell ratio of the rigid polyurethane foams prepared in Examples 1-9 and Comparative Example 1 were determined according to the methods in GB / T 20219-2015 "Sprayed Rigid Polyurethane Foams for Thermal Insulation". The results are shown in Table 1.

[0030] Table 1. Performance test results of rigid polyurethane foams in Examples 1-9 and Comparative Example 1. Compared to Example 1, Comparative Example 1 did not add 220 polyether. The results showed that the compressive strength of the rigid polyurethane foam prepared in Comparative Example 1 was basically the same as that in Example 1, but the open cell ratio was much lower. This indicates that by introducing a low-hydroxyl-value polyether polyol with a hydroxyl value of 50-56 mg / g KOH, the present invention can significantly improve the open cell ratio of rigid polyurethane foam and achieve higher compressive strength.

[0031] Compared to Example 1, in Example 8, 220 polyether was replaced with an equal amount of polyether 2045, and in Example 9, polyether polyol 8345 was replaced with an equal amount of polyether polyol IV6630. The results showed that the compressive strength of the rigid polyurethane foam prepared in Example 8 was lower than that in Example 1, and the open-cell ratio of the rigid polyurethane foam prepared in Example 9 was lower than that in Example 1. This indicates that by limiting the hydroxyl value of low-hydroxyl polyether polyols to 50-56 mg / g KOH and the hydroxyl value of high-functionality polyether polyols to 450-500 mg / g KOH, the open-cell ratio and compressive strength of rigid polyurethane foam can be further improved simultaneously.

[0032] Compared with Examples 1 and 7, the rigid polyurethane foam prepared in Example 2 has higher compressive strength and open cell ratio than that in Examples 1 and 7. This indicates that when the low hydroxyl value polyether polyol accounts for 30% of the polyol mass and the high functionality polyether polyol accounts for 70% of the polyol mass, the prepared rigid polyurethane foam has higher compressive strength and open cell ratio.

[0033] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An open-cell rigid polyurethane foam, characterized in that, The raw materials include the following components by weight: 100 parts polyol, 0.5-5 parts catalyst, 0.5-4 parts water, 5-40 parts foaming agent, 0.5-3 parts surfactant, 0.5-3 parts cell opener, and 150-160 parts isocyanate; the polyol includes low hydroxyl value polyether polyol and high functionality polyether polyol. The hydroxyl value of the low hydroxyl polyether polyol is 50-56 mg / g KOH; The polyol is composed of the following weight percentages: 30% low hydroxyl value polyether polyol and 70% high functionality polyether polyol; The functionality of the low hydroxyl value polyether polyol is 2 ≤ functionality ≤ 3; The high-functionality polyether polyol has a hydroxyl value of 450-500 mg / g KOH and a functionality ≥4.

2. The open-cell rigid polyurethane foam according to claim 1, characterized in that, The catalyst comprises one or more of N,N-dimethylcyclohexylamine, N,N-dimethylbenzylamine, triethylenediamine, triethanolamine, dimethylethanolamine, triethylamine, bis(2-methylamino)ethyl ether, di-n-butyltin dilaurate, stannous octanoate, bismuth isooctanoate, lead isooctanoate, lead naphthenate, tetrabutyl titanate, and tetraisopropyl titanate.

3. The open-cell rigid polyurethane foam according to claim 1, characterized in that, The foaming agent includes one or more of n-pentane, cyclopentane, isopentane, dichlorofluoroethane, pentafluoropropane, and trans-1,3,3,3-tetrafluoropropylene.

4. The open-cell rigid polyurethane foam according to claim 1, characterized in that, The surfactant is silicone oil.

5. The method for preparing an open-cell rigid polyurethane foam according to claim 1, characterized in that, Includes the following steps: S1. Weigh the raw materials as described in claim 1 and set aside; S2. After mixing polyol, catalyst, water, foaming agent, surfactant, and cell opener, a mixture is obtained; S3. Add isocyanate to the mixture and mix to foam, thus obtaining open-cell rigid polyurethane foam.

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