Polyurethane sponge and preparation method thereof

Abstract

This invention discloses a polyurethane foam and its preparation method. The polyurethane foam, by weight, comprises 100 parts polyether polyol, 0.1-2.5 parts catalyst, 0.2-2 parts silicone foam stabilizer, 0.1-5 parts chain extender, 0.5-5 parts water, 0.5-10 parts formaldehyde remover, and 36-60 parts isocyanate. The formaldehyde remover comprises 1-4 parts nano zinc oxide, 0.5-2 parts dispersant, and 0.5-5 parts cell opener. The dispersant is a polyether polyol with a molecular weight of 1000-5000, a functionality of 2, and an EO content of not less than 50%. The cell opener is a polyether polyol with a molecular weight of 2000-6000, a functionality of 2-3, and an EO content of not less than 60%. The ratio of nano zinc oxide, dispersant, and cell opener in the formaldehyde remover is 2:1:1. The polyurethane sponge provided by this invention can achieve high air permeability, high antibacterial rate, and excellent formaldehyde removal performance under no-light conditions.

Description

Technical Field

[0001] This invention relates to polyurethane materials, and more particularly to a polyurethane sponge and its preparation method. Background Technology

[0002] Polyurethane foam is a porous foam material made of polyurethane. It is lightweight, soft, sound-absorbing, heat-insulating, and cushioning, and is widely used in home furnishings, industry, and medical fields. Currently, many foam products on the market have shortcomings in odor removal, formaldehyde removal, and antibacterial properties during use. Mattresses, in particular, are prone to volatile organic compound (VOC) pollution during use and are susceptible to mold and bacteria growth, producing unpleasant odors and affecting the user's health.

[0003] CN117510777A discloses a method for preparing a photocatalyst-free polyurethane air cushion sponge. The method involves adding photocatalyst powder to the raw materials, resulting in an air cushion sponge containing a photocatalyst. This allows the sponge to possess deodorizing, sterilizing, mildew-proofing, and stain-resistant self-cleaning functions under light-free conditions. The sponge can effectively kill bacteria such as Escherichia coli, Staphylococcus aureus, and mold, as well as viruses such as influenza and enteroviruses. It can also decompose and neutralize toxins released by bacteria or fungi. However, the method uses sintering followed by milling in the preparation of the supported catalyst, which makes it difficult to achieve nanoscale particle sizes. The nanofiller and its shape determine the contact area with the environment and the catalytic effect. Furthermore, a series of formaldehyde removal catalysts, represented by titanium dioxide, are photosensitive. In practical applications, the sponge in mattresses and pillows is encased in fabric, making it difficult to effectively perform its true formaldehyde removal function in real-world situations.

[0004] Nano-zinc oxide, when excited by light, can separate electrons and holes. Electrons, acting as active centers, can react with oxygen and moisture in the air to produce active factors such as hydroxyl radicals and superoxide anions. These active factors possess extremely strong chemical activity, reacting with odor molecules containing active hydrogen, such as hydrogen sulfide and ammonia, to remove odors. Simultaneously, they can decompose harmful gases such as formaldehyde and benzene. This is the mechanism of photocatalytic odor removal and formaldehyde decomposition. However, typical home environments lack strong ultraviolet radiation, and many application environments are not exposed to light at all, preventing it from fully functioning.

[0005] In existing sponge materials, single nano zinc oxide is usually used as a formaldehyde removal agent. Although it can achieve a certain formaldehyde removal effect, its dispersibility in polyether polyol is not very good. It often produces undesirable phenomena such as large pores or even collapsed bubbles due to filler aggregation. Summary of the Invention

[0006] Purpose of the invention: The purpose of this invention is to provide a polyurethane sponge with high air permeability, high antibacterial rate, and excellent formaldehyde removal properties under light-free conditions.

[0007] Another object of the present invention is to provide a simple method for preparing polyurethane foam.

[0008] Technical solution: The polyurethane foam of the present invention comprises, by weight, 100 parts polyether polyol, 0.1-2.5 parts catalyst, 0.2-2 parts silicone foam stabilizer, 0.1-5 parts chain extender, 0.5-5 parts water, 0.5-10 parts formaldehyde remover and 36-60 parts isocyanate, wherein the formaldehyde remover comprises 1-4 parts nano zinc oxide, 0.5-2 parts dispersant and 0.5-5 parts cell opener.

[0009] Preferably, the dispersant is a polyether polyol with a molecular weight of 1000-5000, a functionality of 2, and an EO content of not less than 50%.

[0010] Preferably, the pore-opening agent is a polyether polyol with a molecular weight of 2000-6000, a functionality of 2-3, and an EO content of not less than 60%.

[0011] Preferably, in the formaldehyde removal agent, the ratio of nano zinc oxide, dispersant, and pore-opening agent is 2:1:1.

[0012] Preferably, the dispersant is CHE-L64 and the pore-opening agent is CHK-350D.

[0013] Preferably, the polyether polyol has a hydroxyl value of 20-85 and a functionality of 2-6.

[0014] Preferably, the isocyanate is selected from at least one of MDI, TDI, PMDI, HDI, IPDI, and H12MDI.

[0015] Preferably, the catalyst is at least one of an amine catalyst and a metal catalyst. The amine catalyst is selected from at least one of JEFFCAT DPA, JEFFCAT ZF-10, DABCO NE1050, DABCO NE 300, and DABCO T-12. The metal catalyst is selected from at least one of dibutyltin dilaurate and dibutyltin diacetate. The silicone foam stabilizer is at least one of Niax L-580 and Dabco DC5950. The chain extender is selected from at least one of ethylene glycol, butanediol, diethylene glycol, diethanolamine, triethanolamine, trimethylolpropane, and glycerol.

[0016] The method for preparing polyurethane foam according to the present invention includes the following steps:

[0017] (1) Pre-dispersion preparation of formaldehyde removal agent: Mix nano zinc oxide, dispersant and pore opener, and pre-dispersion into formaldehyde removal agent slurry;

[0018] (2) Preparation of component A: Mix polyether polyol, catalyst, organosilicon foam stabilizer, chain extender and water in proportion, add the formaldehyde removal agent obtained in step (1), mix, and obtain component A;

[0019] (3) Preparation of polyurethane sponge: Isocyanate is added to component A, and polyurethane sponge is obtained after foaming and curing.

[0020] Preferably, the stirring speed of the pre-dispersion in step (1) is 2500-5000 RPM, and a high-speed dispersing disc is used.

[0021] Invention principle: In order to better disperse nano zinc oxide in polyether polyol, this invention uses a dispersant and combines it with a pore-opening agent or other polyether pre-dispersed formaldehyde removal agent slurry, which can improve the dispersibility of formaldehyde removal agent in polyether polyol, thereby avoiding adverse phenomena such as large pores or even bubble collapse caused by filler aggregation.

[0022] This method uses polyether polyols with a molecular weight of 1000-5000, a functionality of 2, and an EO content of not less than 50% as dispersants. The high polarity and hydrophilicity of the high EO segment help to better disperse the nano-zinc oxide powder, facilitating its more uniform mixing in the polyether system and preventing powder agglomeration that damages the cell structure. Furthermore, the high EO dispersant used in this invention is hydroxyl-terminated, participating in the reaction and ultimately becoming the foaming material itself.

[0023] The cell opener used in this method has an EO value of over 60%. High EO content, due to its hydrophilicity and the polarity difference between it and traditional PO segments, results in better cell opening in the foam. Furthermore, the high EO content assists the dispersant in helping zinc oxide disperse better in the polyether. A key difference between dispersants and cell openers lies in the distribution of EO content within the cell segments. The addition of a cell opener affects the cell structure; in some systems, the absence of a cell opener leads to sponge shrinkage, while excessive cell opener results in coarse cells and even cell collapse. Considering cost factors, the amount of cell opener added generally does not exceed five parts.

[0024] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: (1) By pre-dispersing nano zinc oxide with dispersant and pore-opening agent into a slurry, the problem of agglomeration of nano zinc oxide particles in polyether polyol is solved, ensuring uniform dispersion of filler and thus improving formaldehyde removal performance; (2) Adding dispersant L64 to nano zinc oxide, the two produce a synergistic effect, making nano zinc oxide more uniformly dispersed in the sponge, thereby improving the formaldehyde removal performance of sponge material; (3) Adding pore-opening agent to formaldehyde removal agent slurry, so that the sponge has a certain degree of openness, with an air permeability greater than 115L / min, and good air circulation between the sponge interior and the surrounding environment, further realizing the sponge's formaldehyde removal and other cleaning functions, purifying and cleaning the surrounding environment; (4) High-speed pre-dispersion treatment of nano zinc oxide, and adding pore-opening agent during the pre-dispersion process to protect the foam structure from being destroyed by nano zinc oxide during the foaming process; (5) Using nano zinc oxide, the sponge becomes a non-photocatalytic material, and the formaldehyde removal performance is still excellent under lightless conditions. Detailed Implementation

[0025] The technical solution of the present invention will be further described below in conjunction with embodiments.

[0026] The relevant information of the raw materials used in this invention is shown in Table 1. The nano zinc oxide used in this invention was prepared according to the method in the patent document with publication number CN111185170A entitled "A method for preparing a nano zinc oxide-encapsulated nano silver antibacterial composite material".

[0027] Table 1 Raw Material List

[0028]

[0029]

[0030] Example 1

[0031] The method for preparing polyurethane foam according to the present invention includes the following steps:

[0032] (1) Pre-dispersion preparation of formaldehyde removal agent: 50 parts by weight of nano zinc oxide, 25 parts of dispersant CHE-L64 and 25 parts of pore opener CHK-350D are mixed and stirred using a high-speed dispersing disc at a speed of 2500-5000 RPM to pre-disperde the formaldehyde removal agent slurry.

[0033] (2) Preparation of component A: By weight, add 4 parts of the formaldehyde removal agent slurry prepared in step (1) to a mixture of 100 parts of polyether polyol (20 parts CHE-330N, 60 parts CHE-5603, 19 parts CHE-507LF, 1 part CHK-350D), 0.26 parts of catalyst (0.13 parts JEFFCAT DPA, 0.08 parts DABCONE300, 0.05 parts DABCO T-12), 0.6 parts of silicone foam stabilizer (Dabco DC5950), 1.55 parts of chain extender (DEOA), and 2.75 parts of water, mix evenly, and obtain component A.

[0034] (3) Preparation of polyurethane sponge: 37.6 parts of TDI with an isocyanate index of 1.05 were added to component A, mixed evenly and foamed, and after curing treatment, polyurethane sponge was obtained.

[0035] Example 2-3

[0036] By changing some of the substances or their amounts in Example 1, Examples 2-3 were constructed, and the specific changes are shown in Table 2.

[0037] In Examples 1-2, the 100 parts of polyether polyol also included the cell-opening agent CHK-350D to keep the total amount of CHK-350D constant. The purpose of Examples 1-3 was to explore the effect of changes in the amount of formaldehyde remover added on material properties. The formaldehyde remover consisted of nano-zinc oxide, CHE-L64, and CHK-350D in a 2:1:1 ratio. Changes in the amount of formaldehyde remover inevitably led to changes in the amount of CHK-350D added, and changes in the amount of CHK-350D significantly affected the cell structure of the material. To keep its total amount constant, the remaining amount of CHK-350D was added to the 100 parts of polyether polyol. It was not necessary to control the total amount of nano-zinc oxide and CHE-L64 added because their impact on material properties was minimal.

[0038] Example 4

[0039] (1) Pre-dispersion preparation of formaldehyde removal agent: 50 parts by weight of nano zinc oxide, 25 parts of dispersant CHE-L64 and 25 parts of pore opener CHK-350D are mixed and stirred using a high-speed dispersing disc at a speed of 2500-5000 RPM to pre-disperde the formaldehyde removal agent slurry.

[0040] (2) Preparation of component A: By weight, add 2 parts of the formaldehyde removal agent slurry prepared in step (1) to a mixture of 100 parts of polyether polyol (75 parts CHE-330N, 13 parts CHED-28, 10 parts CHE-H45, 2 parts CHK-350D), 1.3 parts of catalyst (0.8 parts JEFFCAT DPA, 0.5 parts DABCO NE300), 0.6 parts of silicone foam stabilizer (0.2 parts Niax L-580, 0.4 parts Dabco DC5950), 4 parts of chain extender (MEG), and 1.1 parts of water. Then add 1 part of color paste (ISOPUR-SA-20804 / 9111) and mix evenly to obtain component A.

[0041] (3) Preparation of polyurethane sponge: Add 60 parts of MDI modified black material (CNF-5305C-B) with an isocyanate index of 1.05 to component A, mix evenly and quickly pour into a mold at a temperature of 60℃, demold after 5 minutes to obtain polyurethane sponge.

[0042] The obtained polyurethane foam was divided into two parts. One part was allowed to diffuse at room temperature for 24 hours, and the other part was placed in a sealed bag for 24 hours. Odor evaluation and comparison were then carried out.

[0043] Table 2 Raw material ratios for each embodiment

[0044]

[0045]

[0046] Comparative Example 1

[0047] (1) By weight, 100 parts of polyether polyol (20 parts CHE-330N, 60 parts CHE-5603, 18 parts CHE-507LF, 2 parts CHK-350D), 0.26 parts of catalyst (0.13 parts JEFFCAT DPA, 0.08 parts DABCO NE300, 0.05 parts DABCO T-12), 0.6 parts of silicone foam stabilizer (Dabco DC5950), 1.55 parts of chain extender (DEOA) and 2.75 parts of water are mixed evenly to obtain component A.

[0048] (2) Preparation of polyurethane sponge: 38.4 parts of TDI with an isocyanate index of 1.05 were added to component A, mixed evenly and foamed, and after curing treatment, polyurethane sponge was obtained.

[0049] Comparative Example 2

[0050] (1) Preparation of component A: By weight, 100 parts of polyether polyol (75 parts CHE-330N, 13 parts CHED-28, 10 parts CHE-H45, 2 parts CHK-350D), 1.3 parts of catalyst (0.8 parts JEFFCAT DPA, 0.5 parts DABCO NE300), 0.6 parts of silicone foam stabilizer (0.2 parts Niax L-580, 0.4 parts Dabco DC5950), 4 parts of chain extender (MEG), 1.1 parts of water, and 1 part of color paste (ISOPUR-SA-20804 / 9111) are mixed evenly to obtain component A.

[0051] (2) Preparation of polyurethane sponge: Add 60 parts of MDI modified black material (CNF-5305C-B) with an isocyanate index of 1.05 to component A, mix evenly and quickly pour into a mold at a temperature of 60℃, demold after 5 minutes to obtain polyurethane sponge.

[0052] The obtained polyurethane foam was divided into two parts. One part was allowed to diffuse at room temperature for 24 hours, and the other part was placed in a sealed bag for 24 hours. Odor evaluation and comparison were then carried out.

[0053] Comparative Example 3

[0054] The similarities between this comparative example and Example 1 will not be repeated here; the differences are as follows:

[0055] In step (1), CHK-350D is replaced with CHE-330N, and in step (2), the amounts of CHE-507LF and CHK-350D are changed to 20 parts and 0 parts, respectively.

[0056] Comparative Example 4

[0057] The similarities between this comparative example and Example 1 will not be repeated here; the differences are as follows:

[0058] In step (1), CHE-L64 is changed to CHE-330N.

[0059] Comparative Example 5

[0060] (1) Preparation of component A: By weight, add 4 parts of nano zinc oxide to a mixture consisting of 100 parts of polyether polyol (20 parts of CHE-330N, 60 parts of CHE-5603, 20 parts of CHE-507LF), 0.26 parts of catalyst (0.13 parts of JEFFCAT DPA, 0.08 parts of DABCO NE300, 0.05 parts of DABCO T-12), 0.6 parts of silicone foam stabilizer (Dabco DC5950), 1.55 parts of chain extender (DEOA), and 2.75 parts of water, mix evenly, and obtain component A.

[0061] (2) Preparation of polyurethane sponge: 36.9 parts of TDI with an isocyanate index of 1.05 were added to component A, mixed evenly and foamed, and after curing treatment, polyurethane sponge was obtained.

[0062] The raw material proportions for each comparison are shown in Table 3.

[0063] Table 3 Raw material ratios for each comparative example

[0064]

[0065] Performance tests were conducted on the samples obtained from each embodiment and comparative example, including core density, molded foam density, air permeability, tensile strength, elongation at break, tear strength, antibacterial rate, formaldehyde removal rate, and odor parameters in both sealed and emitting states. The specific test methods are as follows.

[0066] Core density: Tested according to GB / T 3986-2019.

[0067] Molded foam density: Tested according to GB / T 3986-2019.

[0068] Air permeability: Tested according to ASTM 3574.

[0069] Tensile strength and elongation at break: tested according to GB / T 6344.

[0070] Tear strength: Tested according to GB / T 10808.

[0071] Antibacterial rate: Tested according to GB / T 20944.2.

[0072] Formaldehyde removal rate: Tested according to QB / T 2761.

[0073] Odor test: Tested according to VDA 270.

[0074] The test results for each sample are shown in Table 4. Comparative Example 3 exhibited shrinkage during the experiment, and the sponge material in Comparative Example 5 showed bubble collapse; therefore, these samples were not tested. A comparison of the data from Example 4 and Comparative Example 2 reveals that nano-zinc oxide also has a significant effect on odor removal. However, Examples 1-3, Comparative Example 1, and Comparative Example 4, due to their low density, high porosity and air permeability, exhibited good odor dispersion, resulting in larger errors in odor testing; therefore, odor testing was not conducted on these samples. The products obtained from Examples 4 and Comparative Example 2 were molded foams with higher density and lower foam porosity and air permeability, which facilitates a more objective assessment of odor. However, these factors also affect the formaldehyde removal effect; therefore, formaldehyde removal testing was not conducted on these samples. In Examples 1-3, Comparative Examples 1 and 4, the foam density test was not performed because the product was foamed in an open environment rather than in a closed mold. Therefore, the sample had no foam density. For sponge products foamed in an open environment, the density test is usually a core density test. The outer skin needs to be removed to avoid measurement errors. That is, a sample from the center of the sponge is cut off for the core density test.

[0075] Table 4 Test results for each sample

[0076]

[0077] According to the data in Table 4, adding a certain amount of formaldehyde remover to the formula (Examples 1-3) can not only improve the antibacterial rate of polyurethane foam to over 99%, but also improve its formaldehyde removal rate, which can reach up to 92.3%.

[0078] Adding dispersant CHE-L64 to the formulation leverages its high EO segment polarity and excellent wettability on the surface of nano-zinc oxide. High-speed pre-dispersion significantly improves the dispersion uniformity of the nano-zinc oxide material in the final polyether system, thereby optimizing the uniform distribution of nano-zinc oxide in the sponge and increasing the formaldehyde removal rate. Without this dispersant (Comparative Example 4), the formaldehyde removal rate of the polyurethane sponge only reaches 68.5%, highlighting the necessity of adding a dispersant. The process of adding a dispersant and pre-dispersing the formaldehyde removal agent into a slurry through high-speed stirring allows for more uniform dispersion of nano-zinc oxide in the polyether polyol and the final sponge, preventing powder agglomeration and thus enabling it to function better within the sponge.

[0079] Adding the cell-opening agent CHK-350D to the formulation significantly improves the air permeability of polyurethane foam. When the amount of cell-opening agent added is within the preferred range of this scheme, the air permeability of the polyurethane foam is not less than 115 L / min. However, if this cell-opening agent is not added to the system (Comparative Example 3), the polyurethane foam will shrink. This situation may be related to the state of the system itself. If the flexible foam structure does not have a certain degree of openness, it will cause the polyurethane foam to shrink as a whole after cooling.

[0080] According to the experimental results of Example 1 and Comparative Example 5, under the premise that the amount of formaldehyde removal agent added is 4% of the amount of polyether polyol added, the high-speed pre-dispersion of nano zinc oxide using the combination of dispersant and pore-opening agent can effectively improve its dispersibility in the polyether system and the final polyurethane foam, thereby improving the formaldehyde removal effect of the foam. Conversely, if the nano zinc oxide is not pre-dispersed at high speed (Comparative Example 5) and the powder is added directly during the stirring of polyether, it will be observed that the powder has poor dispersibility under low-speed stirring in polyether. Due to the agglomeration of nano zinc oxide powder, the bubble wall is damaged and the bubble collapse occurs during the subsequent foaming process.

[0081] A comparison of the data from Example 4 and Comparative Example 2 reveals that nano zinc oxide also has a significant effect on deodorization. This is because nano zinc oxide can activate oxygen molecules in the air, thereby decomposing some odor substances such as amines in the sponge and achieving the effect of reducing odor.

Claims

1. A polyurethane foam, characterized in that, The product comprises, by weight, 100 parts polyether polyol, 0.1-2.5 parts catalyst, 0.2-2 parts silicone foam stabilizer, 0.1-5 parts chain extender, 0.5-5 parts water, 0.5-10 parts formaldehyde remover, and 36-60 parts isocyanate. The formaldehyde remover comprises 1-4 parts nano zinc oxide, 0.5-2 parts dispersant, and 0.5-5 parts cell opener. The dispersant is CHE-L64, and the cell opener is CHK-350D. The ratio of nano zinc oxide, dispersant, and cell opener in the formaldehyde remover is 2:1:

1. The formaldehyde remover is prepared by mixing nano zinc oxide, dispersant, and cell opener and pre-dispersing them into a formaldehyde remover slurry.

2. The polyurethane foam according to claim 1, characterized in that, The polyether polyol has a hydroxyl value of 20-85 and a functionality of 2-6.

3. The polyurethane foam according to claim 1, characterized in that, The catalyst is at least one of an amine catalyst and a metal catalyst.

4. The polyurethane foam according to claim 3, characterized in that, The amine catalyst is selected from at least one of JEFFCAT DPA, JEFFCAT ZF-10, DABCO NE1050, and DABCO NE 300; the metal catalyst is selected from at least one of dibutyltin dilaurate and dibutyltin diacetate; the silicone foam stabilizer is selected from at least one of Niax L-580 and Dabco DC5950; the chain extender is selected from at least one of ethylene glycol, butanediol, diethylene glycol, diethanolamine, triethanolamine, trimethylolpropane, and glycerol; and the isocyanate is selected from at least one of MDI, TDI, PMDI, HDI, IPDI, H12MDI, WANNATE MDI-100LL, and CNF-5305 CB.

5. A method for preparing the polyurethane foam according to claim 1, characterized in that, Includes the following steps: (1) Pre-dispersion preparation of formaldehyde removal agent: Mix nano zinc oxide, dispersant and pore opener, and pre-dispersion into formaldehyde removal agent slurry; (2) Preparation of component A: Mix polyether polyol, catalyst, organosilicon foam stabilizer, chain extender and water in proportion, add the formaldehyde removal agent obtained in step (1), mix to obtain component A; (3) Preparation of polyurethane sponge: Isocyanate is added to component A, and polyurethane sponge is obtained after foaming and curing.

6. The preparation method according to claim 5, characterized in that, The stirring speed for pre-dispersion in step (1) is 2000-5000 RPM, using a high-speed dispersing disc.

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