Polyurethane sponge and preparation method thereof

Abstract

The invention discloses a polyurethane sponge and a preparation method thereof, and the polyurethane sponge comprises the following components in parts by weight: 100 parts of polyether polyol, 0.1-2.5 parts of a catalyst, 0.2-2 parts of an organosilicon foam stabilizer, 0.1-5 parts of a chain extender, 0.5-5 parts of water, 0.5-10 parts of a formaldehyde removal agent and 36-60 parts of isocyanate. The formaldehyde removal agent comprises 1-4 parts of nano zinc oxide, 0.5-2 parts of a dispersing agent and 0.5-5 parts of a pore opening agent. The dispersing agent is polyether polyol with the molecular weight of 1000-5000, the functionality of 2 and the EO content of not less than 50%. The pore opening agent is polyether polyol of which the molecular weight is 2000-6000, the functionality is 2-3 and the EO content is not less than 60%. In the formaldehyde removal agent, the ratio of the nano zinc oxide to the dispersing agent to the pore opening agent is 2: 1: 1. The polyurethane sponge provided by the invention can achieve the effects of high air permeability, high bacteriostasis rate and excellent formaldehyde removal performance under a dark condition.

Description

Technical Field

[0001] The invention relates to a polyurethane material, in particular to a polyurethane sponge and a preparation method thereof. Background Art

[0002] Polyurethane sponge is a porous foam material made of polyurethane. It boasts lightweight, soft, sound-absorbing, heat-insulating, and cushioning properties, making it widely used in household, industrial, and medical applications. Currently, many sponge products on the market lack odor removal, formaldehyde removal, and antibacterial properties. Mattresses, in particular, are prone to volatile organic compound (VOC) contamination during use, and are prone to mold and bacterial growth, producing unpleasant odors and impacting user health.

[0003] CN117510777A discloses a method for preparing a light-free polyurethane air cushion sponge. Light-free catalyst powder is added to the raw materials, and the resulting air cushion sponge contains light-free catalyst. This allows the air cushion sponge to have deodorizing, sterilizing, mildew-proofing, and antifouling and self-cleaning properties in the absence of light. The air cushion sponge can effectively kill bacteria such as Escherichia coli, Staphylococcus aureus, and mold, as well as viruses such as influenza and enterovirus, and can decompose and harmlessly treat toxins released by bacteria or fungi. However, the method employs a post-sintering milling process to prepare the supported catalyst, making it difficult to achieve nanometer-scale particle sizes. Nanofillers and their shape determine the contact area with the environment and the catalytic effect. Furthermore, a series of formaldehyde-removing catalysts, represented by titanium dioxide, are photosensitive. In practical applications, the sponges are wrapped in fabric in mattresses and pillows, making it difficult to effectively perform their true formaldehyde-removing functions in real life.

[0004] Nano-zinc oxide, when stimulated by light, can separate electrons and holes. Electrons, acting as active centers, react with oxygen and moisture in the air to produce hydroxyl radicals, superoxide anions, and other active factors. These highly chemically active factors can react with hydrogen sulfide, ammonia, and other odor molecules containing active hydrogen to remove odors. They can also decompose harmful gases such as formaldehyde and benzene. This is the mechanism by which photocatalysts remove odors and decompose formaldehyde. However, typical homes lack strong ultraviolet light, and many applications lack exposure to light, preventing their full effectiveness.

[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 polyols is not very good, and often results in undesirable phenomena such as coarse bubbles or even collapsed bubbles due to filler aggregation. Summary of the Invention

[0006] Purpose of the invention: The purpose of the present invention is to provide a polyurethane sponge with high air permeability, high antibacterial rate and excellent formaldehyde removal performance under lightless conditions.

[0007] Another object of the present invention is to provide a method for preparing a polyurethane sponge that is easy to operate.

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

[0011] Preferably, in the formaldehyde remover, 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, and the metal catalyst is selected from at least one of dibutyltin dilaurate and dibutyltin diacetate; the organosilicon foam stabilizer is at least one of Niax L-580 and Dabco DC5950; and 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 the polyurethane sponge of the present invention comprises the following steps: (1) Pre-dispersion preparation of formaldehyde remover: Mix nano zinc oxide, dispersant, and pore opening agent and pre-disperse to form formaldehyde remover slurry; (2) Preparation of component A: polyether polyol, catalyst, organosilicon foam stabilizer, chain extender, and water are mixed in proportion, and the formaldehyde scavenger obtained in step (1) is added and mixed to obtain component A; (3) Preparation of polyurethane sponge: Add isocyanate to component A and foam and mature to obtain polyurethane sponge.

[0017] Preferably, the stirring speed of the pre-dispersion in step (1) is 2500-5000 RPM, and a high-speed dispersing disk is used.

[0018] Principle of the invention: In order to better disperse nano zinc oxide in polyether polyols, the present invention uses a dispersant and a pore-opening agent or other polyethers to pre-disperse it into a formaldehyde scavenger slurry, which can improve the dispersibility of the formaldehyde scavenger in polyether polyols, thereby avoiding undesirable phenomena such as coarse bubbles or even bubble collapse caused by filler aggregation.

[0019] This method uses a polyether polyol with a molecular weight of 1000-5000, a functionality of 2, and an EO content of at least 50% as a dispersant. The high polarity and hydrophilicity of the high EO segment facilitates better dispersion of the nano-zinc oxide powder, allowing it to more evenly mix into the polyether system, preventing undesirable phenomena such as powder agglomeration and destruction of the foam structure. Furthermore, the high EO dispersant used in this invention is hydroxyl-terminated, participating in the reaction and ultimately becoming the foaming material itself.

[0020] 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 traditional PO segments, enhances cell opening in the foam. Furthermore, the high EO content aids the dispersant in dispersing zinc oxide in the polyether. A key difference between dispersants and cell openers lies in the distribution of EO content within the segments. The addition of a cell opener can affect the cell structure. In some systems, the absence of a cell opener can cause sponge shrinkage, while excessive amounts can lead to coarse cells or even collapse. For cost reasons, the amount of cell opener added is generally limited to no more than five parts.

[0021] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: (1) by pre-dispersing nano zinc oxide with a dispersant and a pore-opening agent into a slurry, the agglomeration problem of nano zinc oxide particles in polyether polyols is solved, ensuring that the filler is evenly dispersed, thereby improving the formaldehyde removal performance; (2) by adding dispersant L64 to nano zinc oxide, the two produce a synergistic effect, making the nano zinc oxide more evenly dispersed in the sponge, thereby improving the formaldehyde removal performance of the sponge material; (3) by adding a pore-opening agent to the formaldehyde removal agent slurry, the sponge has a certain degree of openness, the air permeability is greater than 115L / min, and the air circulation between the inside of the sponge and the surrounding environment is good, further realizing the sponge's formaldehyde removal and other cleaning functions for the surrounding environment, purifying the surrounding environment; (4) the nano zinc oxide is subjected to a high-speed pre-dispersion treatment, and the pore-opening agent is added during the pre-dispersion process to protect the pore structure from being destroyed by the nano zinc oxide during the rising process; (5) by using nano zinc oxide, the sponge becomes a non-photosensitive material, and the formaldehyde removal performance is still excellent under lightless conditions. DETAILED DESCRIPTION

[0022] The technical solution of the present invention will be further described below in conjunction with embodiments.

[0023] The relevant information of the raw materials used in the present invention is shown in Table 1. The nano zinc oxide used in the present invention is prepared according to the method disclosed in the patent document with publication number CN111185170A, entitled "Preparation Method of Nano-zinc Oxide-Coated Nano-Silver Antibacterial Composite Material".

[0024] Table 1 List of raw materials

[0025] Example 1 The method for preparing the polyurethane sponge of the present invention comprises the following steps: (1) Pre-dispersion preparation of formaldehyde remover: Mix 50 parts of nano zinc oxide, 25 parts of dispersant CHE-L64, and 25 parts of pore opening agent CHK-350D by weight, use a high-speed dispersing disk, set the speed to 2500-5000RPM for stirring, and pre-disperse into formaldehyde remover slurry.

[0026] (2) Preparation of component A: 4 parts of the formaldehyde scavenger slurry prepared in step (1) were added to a mixture of 100 parts of polyether polyol (20 parts of CHE-330N, 60 parts of CHE-5603, 19 parts of CHE-507LF, 1 part of CHK-350D), 0.26 parts of catalyst (0.13 parts of JEFFCAT DPA, 0.08 parts of DABCONE300, 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, and the mixture was mixed uniformly to obtain component A.

[0027] (3) Preparation of polyurethane sponge: 37.6 parts of TDI with an isocyanate index of 1.05 was added to component A, mixed evenly and foamed, and after aging treatment, a polyurethane sponge was obtained.

[0028] Example 2-3 Examples 2-3 were constructed by changing some of the substances or addition amounts in Example 1. The specific changes are shown in Table 2.

[0029] In Example 1-2, the cell opener CHK-350D is also included in 100 parts of polyether polyols in order to control the total addition of CHK-350D to be constant. The research purpose of Example 1-3 is to explore the influence of the change of the addition of the formaldehyde scavenger on the material properties. The formaldehyde scavenger is composed of nano zinc oxide, CHE-L64, and CHK-350D in a ratio of 2:1:1. The change of the addition of the formaldehyde scavenger will inevitably lead to the change of the addition of CHK-350D, and the change of the addition of CHK-350D has a greater impact on the material pore structure. In order to control its total amount to be constant, the remainder of CHK-350D is made up in 100 parts of polyether polyols. There is no need to control the total addition of nano zinc oxide and CHE-L64 because they have little impact on the performance of the material.

[0030] Example 4

[0031] (1) Pre-dispersion preparation of formaldehyde remover: Mix 50 parts of nano zinc oxide, 25 parts of dispersant CHE-L64, and 25 parts of pore opening agent CHK-350D by weight, use a high-speed dispersing disk, set the speed to 2500-5000RPM for stirring, and pre-disperse into formaldehyde remover slurry.

[0032] (2) Preparation of component A: To a mixture consisting of 100 parts of polyether polyol (75 parts of CHE-330N, 13 parts of CHED-28, 10 parts of CHE-H45, 2 parts of CHK-350D), 1.3 parts of catalyst (0.8 parts of JEFFCAT DPA, 0.5 parts of DABCO NE300), 0.6 parts of silicone foam stabilizer (0.2 parts of Niax L-580, 0.4 parts of Dabco DC5950), 4 parts of chain extender (MEG), and 1.1 parts of water, 2 parts of the formaldehyde scavenger slurry prepared in step (1) and 1 part of color paste (ISOPUR-SA-20804 / 9111) were added, and the mixture was mixed uniformly to obtain component A.

[0033] (3) Preparation of polyurethane sponge: Add 60 parts of MDI modified black material (CNF-5305 CB) with an isocyanate index of 1.05 to component A, mix well, and quickly pour into a mold at a temperature of 60°C. Demold after 5 minutes to obtain a polyurethane sponge.

[0034] The obtained polyurethane sponge was divided into two parts, one part was allowed to diffuse under room temperature for 24 hours, and the other part was placed in a sealed bag for 24 hours, and then subjected to odor evaluation and comparison.

[0035] Table 2 Ratio of raw materials in each embodiment

[0036] Comparative Example 1 (1) By weight, 100 parts of polyether polyol (20 parts of CHE-330N, 60 parts of CHE-5603, 18 parts of CHE-507LF, 2 parts of CHK-350D), 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 were mixed uniformly to obtain component A.

[0037] (2) Preparation of polyurethane sponge: 38.4 parts of TDI with an isocyanate index of 1.05 was added to component A, mixed evenly and foamed, and after aging treatment, a polyurethane sponge was obtained.

[0038] Comparative Example 2 (1) Preparation of component A: By weight, 100 parts of polyether polyol (75 parts of CHE-330N, 13 parts of CHED-28, 10 parts of CHE-H45, 2 parts of CHK-350D), 1.3 parts of catalyst (0.8 parts of JEFFCAT DPA, 0.5 parts of DABCO NE300), 0.6 parts of silicone foam stabilizer (0.2 parts of Niax L-580, 0.4 parts of Dabco DC5950), 4 parts of chain extender (MEG), 1.1 parts of water, and 1 part of color paste (ISOPUR-SA-20804 / 9111) were mixed uniformly to obtain component A.

[0039] (2) Preparation of polyurethane sponge: Add 60 parts of MDI modified black material (CNF-5305 CB) with an isocyanate index of 1.05 to component A, mix well, and quickly pour into a mold at a temperature of 60°C. Demold after 5 minutes to obtain a polyurethane sponge.

[0040] The obtained polyurethane sponge was divided into two parts, one part was allowed to diffuse under room temperature for 24 hours, and the other part was placed in a sealed bag for 24 hours, and then subjected to odor evaluation and comparison.

[0041] Comparative Example 3 The similarities between this comparative example and Example 1 are not repeated here, except that: The CHK-350D in step (1) was changed to CHE-330N, and the addition amounts of CHE-507LF and CHK-350D in step (2) were changed to 20 parts and 0 parts, respectively.

[0042] Comparative Example 4 The similarities between this comparative example and Example 1 are not repeated here, except that: Change CHE-L64 in step (1) to CHE-330N.

[0043] Comparative Example 5 (1) Preparation of component A: 4 parts of nano zinc oxide were added to a mixture of 100 parts of polyether polyol (20 parts of CHE-330N, 60 parts of CHE-5603, and 20 parts of CHE-507LF), 0.26 parts of catalyst (0.13 parts of JEFFCAT DPA, 0.08 parts of DABCO NE300, and 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, and the mixture was mixed uniformly to obtain component A.

[0044] (2) Preparation of polyurethane sponge: 36.9 parts of TDI with an isocyanate index of 1.05 was added to component A, mixed evenly and foamed, and after aging treatment, a polyurethane sponge was obtained.

[0045] The raw material ratios of each comparative example are shown in Table 3.

[0046] Table 3 Ratio of raw materials for each comparative example

[0047] The samples obtained from each embodiment and comparative example were subjected to performance tests, including core density, molded foam density, air permeability, tensile strength, elongation at break, tear strength, antibacterial rate, formaldehyde removal rate, and odor parameters in the closed state and the emitted state. The specific testing methods are as follows.

[0048] Core density: tested according to GB / T 3986-2019.

[0049] Molded foam density: tested according to GB / T 3986-2019.

[0050] Air permeability: tested according to ASTM 3574.

[0051] Tensile strength and elongation at break: tested according to GB / T 6344.

[0052] Tear strength: tested according to GB / T 10808.

[0053] Antibacterial rate: tested according to GB / T 20944.2.

[0054] Formaldehyde removal rate: tested according to QB / T 2761.

[0055] Odor test: Tested according to ASTM 3574.

[0056] The test results of each sample are shown in Table 4. Shrinkage occurred in Comparative Example 3 during the experiment, and collapse occurred in the sponge material of Comparative Example 5, so it was not tested. According to the data comparison of Example 4 and Comparative Example 2, it can be found that nano zinc oxide also has a significant effect in deodorization, while Examples 1-3, Comparative Example 1, and Comparative Example 4 have low density, large open-pore air permeability, good odor dispersion, and large error in odor testing, so odor testing is not arranged. The products obtained by selecting Example 4 and Comparative Example 2 are molded foams with high density, low foam open-pore and air permeability, which help to objectively evaluate odor. But at the same time, these will affect the aldehyde removal effect, so the sample was not tested for aldehyde removal. In Examples 1-3, Comparative Example 1, and Comparative Example 4, the molded 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 molded foam density. For sponge products foamed in an open environment, the density test is usually a core density test, and the skin needs to be removed to avoid measurement errors, that is, a sample from the center of the sponge is cut for a core density test.

[0057] Table 4 Test results of each sample

[0058] According to the data in Table 4, adding a certain amount of formaldehyde removal agent (Examples 1-3) to the formula can not only increase the antibacterial rate of the polyurethane sponge to more than 99%, but also increase its formaldehyde removal rate, up to 92.3%.

[0059] By adding the dispersant CHE-L64 to the formula, leveraging its high EO segment polarity and excellent wettability on the surface of nano-zinc oxide, high-speed pre-dispersion can significantly improve the dispersion uniformity of the nano-zinc oxide material in the final polyether system, thereby optimizing the uniform distribution of the nano-zinc oxide in the sponge and increasing the formaldehyde removal rate. Without the dispersant (Comparative Example 4), the formaldehyde removal rate of the polyurethane sponge only reaches 68.5%, demonstrating 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 can more evenly disperse the nano-zinc oxide in the polyether polyol and the final sponge, preventing powder agglomeration and thus better performing its function in the sponge.

[0060] Adding the cell-opening agent CHK-350D to the formulation significantly improves the air permeability of the polyurethane sponge. When the amount of cell-opening agent added is within the preferred range of this solution, the air permeability of the polyurethane sponge is no less than 115 L / min. However, if this cell-opening agent is omitted (Comparative Example 3), the polyurethane sponge shrinks. This phenomenon may be related to the state of the system itself. If the soft foam structure lacks a certain degree of openness, the polyurethane sponge will shrink overall after cooling.

[0061] According to the experimental results of Example 1 and Comparative Example 5, it can be seen that, under the premise that the amount of formaldehyde scavenger added is 4% of the amount of polyether polyol added, the use of a dispersant and a pore opener to pre-disperse nano zinc oxide at high speed can effectively improve its dispersibility in the polyether system and the final polyurethane sponge, thereby improving the formaldehyde removal effect of the sponge; on the contrary, if the nano zinc oxide is not pre-dispersed at high speed (Comparative Example 5), and the powder is directly added during the stirring process of the polyether, it will be observed that the powder has poor dispersibility under low-speed stirring in the polyether, and due to the agglomeration of the nano zinc oxide powder, the bubble wall is damaged in the subsequent foaming process and bubble collapse occurs.

[0062] According to the data comparison of Example 4 and Comparative Example 2, it can be found that nano zinc oxide also has a significant effect in 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, thereby achieving the effect of reducing odor.

Claims

1. A polyurethane sponge, characterized in that: The invention comprises, by weight, 100 parts of polyether polyol, 0.1-2.5 parts of catalyst, 0.2-2 parts of organosilicon foam stabilizer, 0.1-5 parts of chain extender, 0.5-5 parts of water, 0.5-10 parts of formaldehyde scavenger and 36-60 parts of isocyanate, wherein the formaldehyde scavenger comprises 1-4 parts of nano zinc oxide, 0.5-2 parts of dispersant and 0.5-5 parts of pore opener.

2. The polyurethane sponge according to claim 1, characterized in that 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%.

3. The polyurethane sponge according to claim 1, characterized in that 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%.

4. The polyurethane sponge according to claim 1, characterized in that In the formaldehyde remover, the ratio of nano zinc oxide, dispersant and pore opening agent is 2:1:

1.

5. The polyurethane sponge according to claim 1, characterized in that The dispersant is CHE-L64, and the pore opening agent is CHK-350D.

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

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

8. The polyurethane sponge according to claim 7, characterized in that 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 organosilicon 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.

9. A method for preparing the polyurethane sponge according to claim 1, characterized in that: The following steps are involved: (1) Pre-dispersion preparation of formaldehyde remover: Mix nano zinc oxide, dispersant, and pore opening agent and pre-disperse to form formaldehyde remover slurry; (2) Preparation of component A: polyether polyol, catalyst, organosilicon foam stabilizer, chain extender, and water are mixed in proportion, and the formaldehyde scavenger obtained in step (1) is added and mixed to obtain component A; (3) Preparation of polyurethane sponge: Add isocyanate to component A and foam and mature to obtain polyurethane sponge.

10. The preparation method according to claim 9, characterized in that The stirring speed of the pre-dispersion in step (1) is 2000-5000RPM, and a high-speed dispersing disk is used.

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