Microcapsule type rigid polyurethane foam and method for producing the same
The preparation of rigid polyurethane foam by microencapsulating DOPO flame retardant solves the problem of flammability of rigid polyurethane foam, improves the flame retardant and compression resistance of the material, and enhances its safety in filling, heat insulation and thermal insulation fields.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CHANGZHOU UNIV
- Filing Date
- 2023-06-19
- Publication Date
- 2026-06-05
AI Technical Summary
Existing rigid polyurethane foam materials are flammable and can exacerbate fires. Furthermore, the addition of flame retardants can lead to a decline in physical properties. Therefore, there is an urgent need to develop rigid polyurethane foam materials with excellent flame retardant properties.
Microencapsulation technology is used to prepare microencapsulated functional additives by using polymethyl methacrylate as the shell and DOPO as the core of DOPO flame retardant additives. These additives are then used in rigid polyurethane foam materials in combination with polyether or polyester polyols, foam stabilizers, blowing agents and catalysts. The microencapsulated rigid polyurethane foam materials are prepared by high-speed mixing and foaming.
This technology enhances the flame retardant properties of rigid polyurethane foam materials, while also improving their compressive strength and mechanical properties, thereby increasing their safety and application in filling, insulation, and thermal insulation fields.
Smart Images
Figure CN117050504B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of polyurethane foam materials, and more particularly to a microcapsule-type rigid polyurethane foam material and its preparation method. Background Technology
[0002] Rigid polyurethane foam is a high-performance, lightweight material with excellent insulation properties, good corrosion resistance, and mechanical properties. It is widely used in filling, insulation, and thermal insulation applications, including floating roofs for crude oil storage tanks, insulation layers for oil and gas pipelines, and building walls.
[0003] However, rigid polyurethane foam is highly flammable due to its porous structure, which can exacerbate fires and pose a significant threat to personal safety and property. Therefore, improving the flame retardant properties of rigid polyurethane foam is a prerequisite for its widespread application.
[0004] Currently, scholars and enterprises both domestically and internationally have conducted extensive research and development on the flame-retardant properties of rigid polyurethane foam materials, mainly through methods such as adding flame retardants, modifying polyurethane, and introducing nanomaterials. Among these methods, adding flame retardants is one of the most widely used. Flame retardants can reduce the combustion performance of materials and improve their thermal and oxidative stability, thereby enhancing their flame-retardant properties. However, the addition of flame retardants can lead to a certain decrease in the physical properties of the foam material. Therefore, there is an urgent need to develop a rigid polyurethane foam material with excellent flame-retardant properties. Summary of the Invention
[0005] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.
[0006] In view of the problems existing in the above and / or prior art, the present invention is proposed.
[0007] Therefore, the purpose of this invention is to overcome the shortcomings of the prior art and provide a microcapsule-type rigid polyurethane foam material.
[0008] To solve the above-mentioned technical problems, the present invention provides the following technical solution:
[0009] The material comprises the following components.
[0010] Polyether or polyester polyols, foam stabilizers, blowing agents, catalysts, microencapsulated functional additives, and isocyanates;
[0011] Among them, the microencapsulated functional additive uses polymethyl methacrylate as the outer shell and the functional additive as the core, and the functional additive is a DOPO flame retardant additive.
[0012] As a preferred embodiment of the microencapsulated rigid polyurethane foam material of the present invention, the material comprises the following components, based on the amount added per 100 parts of resin.
[0013] 100 phr of polyether or polyester polyol, 4 phr of foam stabilizer, 5 phr of blowing agent, 0.10 phr of catalyst, and 160 phr of isocyanate.
[0014] As a preferred embodiment of the microencapsulated rigid polyurethane foam material of the present invention, the addition ratio of the microencapsulated functional additive is 10 wt.% to 15 wt.%.
[0015] As a preferred embodiment of the microencapsulated rigid polyurethane foam material of the present invention, the polyol is a polyester polyol with a molecular weight of 1000, 1500 or 2000 and a hydroxyl content of 3.4%.
[0016] As a preferred embodiment of the microcapsule-type rigid polyurethane foam material of the present invention, wherein the isocyanate is a methylene isocyanate with an NCO content of 35%.
[0017] As a preferred embodiment of the microcapsule-type rigid polyurethane foam material of the present invention, the catalyst is a mixed solution of 33% wt triethylenediamine and 67 wt dipropylene glycol.
[0018] As a preferred embodiment of the microcapsule-type rigid polyurethane foam material of the present invention, the foam stabilizer is a silicone oil-based foam stabilizer with a pH of 4.5; the foaming agent includes deionized water.
[0019] As a preferred embodiment of the microencapsulated rigid polyurethane foam material of the present invention, the method for preparing the microencapsulated functional additive includes:
[0020] 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, polyethylene maleic anhydride copolymer, and distilled water were stirred and mixed. Then, ethylene glycol dimethacrylate, 2,2-azobisisobutyronitrile, and methyl methacrylate were added and the mixture was stirred until white spherical particles appeared. The mixture was cooled to room temperature, filtered, washed, and dried to obtain the microencapsulated functional additive.
[0021] Another objective of this invention is to overcome the shortcomings of the prior art and provide a method for preparing microencapsulated rigid polyurethane foam materials.
[0022] To solve the above-mentioned technical problems, the present invention provides the following technical solution: Polyether or polyester-type polyol, foam stabilizer, blowing agent, catalyst, and microencapsulated functional additives are mixed at high speed, then isocyanate is added, and the mixture is mixed at high speed until the foam expands and foams. After cooling to room temperature, the foam is cured and dried to obtain a microencapsulated rigid polyurethane foam material.
[0023] In a preferred embodiment of the preparation method of the microcapsule-type rigid polyurethane foam material of the present invention, the drying and curing is carried out at 70-85°C for 20-25 hours.
[0024] Beneficial effects of this invention:
[0025] This invention provides a method for preparing a high-compression-resistant flame-retardant rigid polyurethane material. A microencapsulated flame retardant is prepared using polymethyl methacrylate as the outer shell and DOPO flame-retardant additive as the core, and then added to the rigid polyurethane foam system. This method can impart flame-retardant properties to the rigid polyurethane material while improving the foam's compression resistance, thus improving the flame-retardant and mechanical properties of the polyurethane foam material and enhancing its safety when used in filling, insulation, and thermal insulation applications. Attached Figure Description
[0026] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:
[0027] Figure 1 This is a digital image of the foam material with a PMDOPO content of 15 wt% in Example 2.
[0028] Figure 2 The microstructure of the foam material with a PMDOPO content of 15 wt% in Example 2 is shown.
[0029] Figure 3 The stress-strain curve of the foam material with a PMDOPO content of 0 wt% in Example 2 is shown.
[0030] Figure 4 The stress-strain curve of the foam material with a PMDOPO content of 5 wt% in Example 2 is shown.
[0031] Figure 5 The stress-strain curve of the foam material with a PMDOPO content of 10 wt% in Example 2 is shown.
[0032] Figure 6The stress-strain curve of the foam material with a PMDOPO content of 15 wt% in Example 2 is shown.
[0033] Figure 7 The stress-strain curve of the foam material with a PMDOPO content of 20 wt% in Example 2 is shown.
[0034] Figure 8 The stress-strain curve of the foam material with a PMDOPO content of 25 wt% in Example 2 is shown.
[0035] Figure 9 The images show the combustion effects of foam materials with PMDOPO contents of 0 and 15 wt% in Example 2.
[0036] Figure 10 This is a comparison chart of the maximum compressive strength of the foam materials obtained under different amounts of flame retardant added in Example 2 and Comparative Example 1.
[0037] Figure 11 Comparative diagram showing the compressive strength of foam materials prepared with different amounts and types of microcapsule flame retardants for Comparative Examples 2 and 3. Detailed Implementation
[0038] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the examples in the specification.
[0039] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.
[0040] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.
[0041] This invention uses an AGS-10KND universal testing machine to determine the performance of the products of each embodiment and comparative example according to the standard ASTM D1621-00.
[0042] Unless otherwise specified, all raw materials used in this invention are commercially available.
[0043] The correspondence between the abbreviations and Chinese names of the raw materials in this invention is shown in the table below.
[0044]
[0045] Example 1
[0046] 1) Preparation of microencapsulated functional additives:
[0047] 15g DOPO, 2.5g SMA, and 120ml deionized water were mixed at 80℃ and 1500r / min using a magnetic stirrer for 30min.
[0048] Add 20 ml MMA, 0.5 g AIBN, and 2.0 g EGDMA, and stir with a magnetic stirrer at 70 °C and 1000 r / min for 6 hours.
[0049] The obtained product was cooled to room temperature, filtered and washed with distilled water, and dried in an 80°C oven for 12 hours. The product obtained was microcapsule PMDOPO.
[0050] 2) Dissolve 11.12g of polyester polyol, 0.34g of silicone oil, and 0.1g of A33 in 450ml of deionized water, then add the prepared PMDOPO. Stir the mixture with a magnetic stirrer at 80℃ and 1800r / min for 15min until homogeneous. Add 18g of XDI, and continue stirring at the above temperature and speed for 30s. Stop stirring and place the resulting material in an 80℃ forced-air drying oven for 24h to obtain RPUF / PMDDOPO.
[0051] Example 2
[0052] This embodiment is used to investigate the effect of different PMDOPO addition amounts on the properties of the prepared foam material. The difference between this embodiment and Example 1 is that the PMDOPO addition amount is adjusted to 0wt%, 5wt%, 10wt%, 15wt%, 20wt%, and 25wt%, while the rest of the preparation process is the same as in Example 1, to obtain RPUF / PMDDOPO with different PMDDOPO contents in this embodiment.
[0053] Figure 1 , Figure 2 The images shown are digital pictures and microstructures of the product with a PMDOPO content of 15 wt% in this embodiment. It can be seen that the foam material prepared by this invention has a uniform and dense pore structure, the microcapsule PMDOPO is uniformly incorporated into the pores, the foam formation is good, and the closed-cell rate is high, close to 99%.
[0054] Figures 3-8Stress-strain curves of RPUF / PMDOPO prepared with PMDOPO contents of 0 wt%, 5 wt%, 10 wt%, 15 wt%, 20 wt%, and 25 wt% are shown. It can be seen that the mechanical properties of RPUF increase after the addition of PMDOPO. The compressive strength of RPUF / PMDOPO with PMDOPO content between 10 wt.% and 15 wt.% is approximately four times that of pure RPUF without PMDOPO, demonstrating a significant performance improvement. However, above 15 wt.%, the foam becomes brittle, the pore size becomes too large, and the mechanical properties decrease accordingly. The optimal range is 10 wt.%–15 wt.%.
[0055] Figure 9 From left to right, these are digital photos of pure RPUF, RPUF with 5 wt.% PMDOPO, RPUF with 15 wt.% PMDOPO, and RPUF with 25 wt.% PMDOPO after undergoing a UL-94 vertical burning test. Observation shows that as the additive content increases, after 10 seconds of intermittent burning, the amount of foam melting and shrinkage decreases, and the dripping phenomenon is improved.
[0056] Adding 5 wt.% RPUF resulted in self-extinguishing within 30 seconds after the open flame was removed; adding 15 wt.% RPUF resulted in self-extinguishing within 15-20 seconds; and adding 25 wt.% RPUF resulted in self-extinguishing within 5-10 seconds. Pure RPUF, however, did not self-extinguish and continued to burn with a flame. The content of flame-retardant additives is directly proportional to the flame-retardant and flame-suppressing effects, indicating that the polyurethane material of this invention possesses excellent flame-retardant properties.
[0057] Comparative Example 1
[0058] The difference between this comparative example and Example 1 is that DOPO is not microencapsulated, but DOPO is directly used as a flame retardant with addition amounts of 0wt%, 5wt%, 10wt%, 15wt%, 20wt%, and 25wt%, respectively. The rest of the preparation process is the same as in Example 1, resulting in RPUF / DOPO with different DOPO contents.
[0059] Figure 10 The graph shows a comparison of the maximum compressive strength of foam materials obtained under different amounts of flame retardant added in Example 2 and Comparative Example 1. It can be seen that the compressive strength of the foam material without microencapsulation of the flame retardant DOPO decreases continuously with the increase of the added amount, and is much lower than that of Example 2 with microencapsulation of DOPO.
[0060] Comparative Example 2
[0061] The difference in this comparative example 1 is that DOPO microspheres are coated with polystyrene (PS). Specifically, step 1) of example 1 is adjusted as follows:
[0062] 1.5g of polyvinylpyrrolidone (PVP) was dissolved in anhydrous ethanol. Styrene monomer, crosslinking initiator AIBN and 2.5g of DOPO were added at 70℃, under nitrogen protection and at a speed of 650r / min. Polymerization was carried out for 13h. The product was centrifuged and washed with deionized water to obtain PS-DOPO microcapsules.
[0063] The amount of PS-DOPO microcapsules added in step 2) was adjusted to 0wt%, 5wt%, 10wt%, 15wt%, 20wt%, and 25wt% to obtain RPUF / PS-DOPO with different PS-DOPO contents.
[0064] Comparative Example 3
[0065] The difference in this comparative example 1 is that DOPO microspheres are coated with polyimide (PI). Specifically, step 1) of example 1 is adjusted as follows:
[0066] 2.12 g of p-phenylenediamine (PDA) was dissolved in a quantitative amount of N-methylpyrrolidone (NMP) solution by high-speed stirring. Then, 2.16 g of 3,3',4,4'-benzophenone tetracarboxylic dianhydride (BTDA) was added. The mixture was stirred at 500 r / min for 24 h under a nitrogen atmosphere and at room temperature to obtain an orange-yellow polyimide (PAA) solution.
[0067] Measure 30 ml of PAA solution and 5 g of DOPO and place them into a 50 ml high-temperature reactor with a polytetrafluoroethylene inner liner. React at 180°C for 7 hours in a 60°C forced-air drying oven. After natural cooling, wash the product several times with water and ethanol, and dry it to constant weight to obtain PI-DOPO capsules.
[0068] The amount of PI-DOPO microcapsules added in step 2) was adjusted to 0 wt%, 5 wt%, 10 wt%, 15 wt%, 20 wt%, and 25 wt% to obtain RPUF / PI-DOPO with different PI-DOPO contents.
[0069] Figure 11To prepare foam materials with different amounts and types of microcapsule flame retardants for Comparative Examples 2 and 3, it can be seen that the compressive strength of the foam is improved after adding the above microcapsule flame retardants, but the maximum compressive strength can only reach 1.96 MPa and 1.72 MPa, respectively, which are both less than 2.47 MPa of RPUF / PMDOPO. This indicates that PMMA has obvious strain rate correlation and high-speed brittleness, which determines its good comprehensive mechanical properties and makes it a relatively ideal microsphere material.
[0070] In summary, this invention provides a method for preparing a high-compression-resistant flame-retardant rigid polyurethane material. A microencapsulated flame retardant is prepared using polymethyl methacrylate as the outer shell and DOPO flame-retardant additive as the core, and then added to the rigid polyurethane foam system. This method can impart flame-retardant properties to the rigid polyurethane material while simultaneously improving the foam's compression resistance, thus improving the flame-retardant and mechanical properties of the polyurethane foam material and enhancing its safety when used in filling, insulation, and thermal insulation applications.
[0071] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.
Claims
1. A microencapsulated rigid polyurethane foam material, characterized in that: The material comprises the following components, based on the amount to be added per 100 parts of resin. 100 phr of polyether or polyester polyol, 4 phr of foam stabilizer, 5 phr of blowing agent, 0.10 phr of catalyst, 160 phr of isocyanate, and the microencapsulated functional additives are added in proportions of 10 wt.% to 15 wt.% of the above components. The microencapsulated functional additive uses polymethyl methacrylate as the outer shell and a functional additive as the core. The functional additive is a DOPO flame-retardant additive. The preparation method includes... 15g DOPO, 2.5g SMA, and 120ml deionized water were mixed at 80℃ and 1500r / min using a magnetic stirrer for 30min. Then, 20ml MMA, 0.5g AIBN, and 2.0g EGDMA were added, and the mixture was stirred at 70℃ and 1000r / min using a magnetic stirrer for 6h. The resulting product was cooled to room temperature, filtered and washed with distilled water, and dried in an 80℃ forced-air drying oven for 12h. The resulting product is the DOPO flame retardant additive.
2. The microencapsulated rigid polyurethane foam material according to claim 1, characterized in that: The polyol is a polyester-type polyol with a molecular weight of 1000, 1500 or 2000 and a hydroxyl content of 3.4%.
3. The microencapsulated rigid polyurethane foam material according to claim 1, characterized in that: The isocyanate is a methylene isocyanate with an NCO content of 35%.
4. The microencapsulated rigid polyurethane foam material according to claim 1, characterized in that: The catalyst is a mixed solution of 33% wt triethylenediamine and 67 wt dipropylene glycol.
5. The microencapsulated rigid polyurethane foam material according to claim 1, characterized in that: The foam stabilizer is a silicone oil-based foam stabilizer with a pH of 4.5; the foaming agent includes deionized water.
6. The method for preparing the microencapsulated rigid polyurethane foam material according to any one of claims 1 to 5, characterized in that: include, Polyether or polyester polyol, foam stabilizer, blowing agent, catalyst, and microencapsulated functional additives are mixed at high speed, and then isocyanate is added. The mixture is mixed at high speed, the foam expands and foams, and after cooling to room temperature, it is cured and dried to obtain microencapsulated rigid polyurethane foam material.
7. The method for preparing the microencapsulated rigid polyurethane foam material as described in claim 6, characterized in that: The drying and ripening process involves ripening at 70–85°C for 20–25 hours.