Low-odor polyurethane foam material and preparation method thereof

Abstract

The invention relates to a low-odor polyurethane foam material and a preparation method thereof, and mainly solves the problem of strong odor of a polyurethane foam material in the prior art. The novel low-odor polyurethane foam material is composed of a component A and a component B, the weight part ratio of the component A to the component B is (0.3-3): 1, and the component A is selected from one of water or aqueous dispersion in parts by weight; the component B comprises 60-95 parts of hydrophilic polyether polyol and 5-40 parts of isocyanic acid, the problems are well solved, and the polyurethane foam material can be applied to polyurethane foam materials.

Description

Technical Field

[0001] The invention relates to a low-odor polyurethane foam material and a preparation method thereof. Background Art

[0002] Polyurethane is a common synthetic material widely used in furniture, clothing, car seats and other fields. The odor emitted by polyurethane foam usually does not cause immediate harm to the human body, but long-term exposure to high concentrations of polyurethane odor may cause discomfort. Although the odor emitted by polyurethane is generally not toxic, polyurethane products may release volatile organic compounds such as formaldehyde during the production process. Long-term exposure to high concentrations of VOCs may have potential health effects. With the enhancement of national environmental awareness, higher requirements have been put forward for the environmental protection, odor, VOC, etc. of polyurethane products.

[0003] According to the national standard GB18586-2001, a more stringent definition of VOC is selected, which is the general term for organic volatiles with a melting point below room temperature and a boiling point between 50 and 260°C, including benzene, toluene, xylene and other organic volatile substances. The standard stipulates that the total VOC amount is less than 35ppm.

[0004] The odor test method in the prior art is to place the sample in a glass container, bake it in an oven at 80±2℃ for 2h±10min, then take the container out of the oven, cool it in the air to 60±5℃, and let the tester evaluate the odor. The number of evaluators is at least 3, and the difference between the scores given by each person cannot be greater than 2 points. If it is greater than 2 points, it must be re-evaluated by 5 people.

[0005] There are four main types of volatile organic compounds in polyurethane foam: (1) antioxidant BHT or BHT homologues. This type of antioxidant is mainly derived from polyols and is therefore often not taken seriously; (2) foam stabilizers, mainly silicone-based compounds; (3) catalysts, mainly tertiary amine organic compounds and divalent or tetravalent organic tin compounds; (4) volatile flame retardants. The higher the content of flame retardants, the higher the volatility. Therefore, in order to reduce the VOC content in polyurethane materials, it is necessary to select or modify the raw materials used for polyurethane foaming in order to effectively reduce the presence of organic volatiles.

[0006] According to the "Research on Polyurethane Foam Plastics and Odor" published by Jiang Baolin and others from GAC Group in the Polyurethane Industry in 2019, we can see that the VOC substances in polyurethane foam are mainly aldehyde compounds, alcohol compounds, amine compounds, ester compounds and benzene compounds, while its amine odor mainly comes from amine compounds, and the solvent odor mainly comes from benzene compounds, alcohol compounds and alkanes.

[0007] Chinese patent CN201810037318.5 discloses a low-VOC polyurethane foam and its preparation method, which mainly solves the problems of high VOC value, high content of benzene and aldehyde substances, and strong odor in the prior art. By adopting a low-VOC low-odor polyurethane foam, composed of component A and component B, component A and component B are 1:0.8 to 2.0 in weight percentage, wherein component A includes component A1 and component A2, wherein component A1 is composed of polyether polyol, hydrazine hydrate and isocyanate, component A2 is composed of polyester polyol, foaming agent, catalyst, crosslinking agent and silicone oil, component B is isocyanate and its preparation method, the technical solution solves the problem well, and can be used in the industrial production of low-VOC polyurethane foam.

[0008] Chinese patent CN202011137517.7 discloses a low-odor, low-VOC polyurethane foam and its preparation method. The mixed A material components are: 50-99 parts of polyether polyol, 1-50 parts of polymer polyether polyol, 0.1-1.5 parts of amine catalyst, 0.1-2 parts of aldehyde scavenger, 0.1-1.5 parts of silicone oil, 0.1-9.5 parts of water, and 0.1-1.5 parts of foaming agent; B material is isocyanate; the mass ratio of A material to B material is 1:1-1.8. Mix polyether polyol, polymer polyether polyol, amine catalyst, silicone oil, water, and foaming agent evenly; then add aldehyde scavenger and mix again; pour into the mold after mixing and stirring; close the mold and mature; obtain the finished product. The polyurethane foam has low odor, the odor level is not higher than level 2, low VOC, the foam VOC is not more than 30ug / g, and the physical properties of the finished product are excellent, which effectively improves the problems of high VOC and odor of polyurethane foam.

[0009] At the same time, Cheng Yafei, Li Yutong and others published an article titled "Study on the Effect of Activated Carbon Filled Passenger Car Seat Foam on Odor VOC", in which they attempted to add modified activated carbon to the polyurethane foam reaction system to obtain a material that can continuously absorb small molecular odor substances remaining in the polyurethane foam. The dispersibility of modified activated carbon with different particle sizes in isocyanate solution was studied, and the optimal particle size range of activated carbon filling was found. On the basis of ensuring the mechanical strength of polyurethane foam, the filled activated carbon plays a good role in absorbing odor and VOC in the car.

[0010] It is worth noting that the explorations in the above patents and articles are all based on the current formulation technology route of polyurethane, which uses some absorbents or low-odor raw materials to reduce odor and VOC volatility. The solutions proposed for VOC and odor in some links have certain limitations in their effectiveness. Summary of the invention

[0011] One of the technical problems to be solved by the present invention is that the polyurethane foam material in the prior art has a strong odor. A new low-odor polyurethane foam material is provided, which has the advantage of low odor.

[0012] The second technical problem to be solved by the present invention is to provide a method for preparing a low-odor polyurethane foam material corresponding to the first technical problem to be solved.

[0013] In order to solve one of the above technical problems, the technical solution adopted by the present invention is as follows: a low-odor polyurethane foam material, composed of component A and component B, the weight ratio of component A to component B is 0.3-3:1, wherein component A is selected from one of water or aqueous dispersion; component B, calculated by weight, includes: 60-95 parts of hydrophilic polyether polyol and 5-40 parts of isocyanic acid.

[0014] In the above technical solution, preferably, the molecular weight of the hydrophilic polyether polyol is 100-3000, and the functionality is 2-3; the isocyanic acid is selected from at least one isocyanic acid monomer.

[0015] In the above technical solution, preferably, the aqueous dispersion is selected from a polymer aqueous dispersion with a solid content of 2 to 60%, an inorganic aqueous dispersion or an aqueous dispersion with added functional additives.

[0016] In the above technical scheme, preferably, the hydrophilic polyether polyol is selected from at least one of PEG-2000, CHE-L64, CHE-2070E, CHED-28, CHE-330N, CHE-3602, and CHE-608; the isocyanate monomer is selected from at least one of HDI, IPDI, H12MDI, XDI, MDI, TDI, MI, biuret or trimer.

[0017] In the above technical scheme, preferably, the aqueous dispersion is composed of water and water-dispersible substances, the solid content of the aqueous dispersion is in the range of 2 to 60%, and the water-dispersible substance is selected from at least one of low-odor acrylic emulsion, polyvinyl alcohol emulsion, EVA emulsion, natural latex, styrene-butadiene latex, wax emulsion, diethylene glycol or calcium carbonate.

[0018] In the above technical solution, preferably, the weight ratio of component A to component B is 0.3 to 2:1.

[0019] To solve the second of the above technical problems, the technical solution adopted by the present invention is as follows: a method for preparing a low-odor polyurethane foam material, comprising the following steps:

[0020] (1) Preparation of component B: 60-95 parts of hydrophilic polyether polyol and 5-40 parts of isocyanic acid are added to a reaction kettle, heated to 75-80° C., kept warm for 1-2 hours, and cooled to obtain component B;

[0021] (2) Component A and component B are uniformly mixed in a weight ratio of 0.3 to 3:1 to obtain a low-odor polyurethane foam material.

[0022] The present invention provides a new preparation path and process for low-odor polyurethane foam material, which realizes not using raw materials such as silicone oil and catalyst, and uses low-odor polyether polyol to further reduce the risk of odor source, obtains low-odor polyurethane foam material, and achieves good technical effect. At the same time, the more the amount of antioxidant BHT or BHT homologues, foam stabilizer, catalyst, and volatile flame retardant, the higher the volatility. Therefore, to reduce the VOC content in polyurethane materials, it is necessary to simultaneously select raw materials that do not contain these four types of volatile organic compounds as much as possible. The present invention uses a brand-new preparation method, first by using a polyether combination with a certain high EO content ratio and functionality requirements, so that it is first reacted with isocyanic acid to synthesize a prepolymer. By dispersing the synthesized prepolymer in an aqueous phase system, chain extension and foaming can be achieved to obtain a polyurethane foam material with a fine pore structure. It is worth noting that, unlike the traditional polyurethane foaming process, the reaction usually occurs in an oil phase system with a polyether component as the main body, and the foaming process of the present invention is realized in an aqueous system. Water accounts for a significant proportion in the system of the present invention and directly becomes component A, and plays an important role. In addition to a small amount of water participating in the chemical reaction and foaming, a large amount of excess water enables the prepolymer containing a high EO content polyether segment to be quickly and evenly dispersed into the water phase for chain extension and foaming, replacing the emulsification effect of silicone oil, and controlling the final foam molding density and pore structure through key parameters such as the NCO content of the prepolymer. In addition, the dispersed substances in the aqueous dispersion in component A can be added with some functional substances according to needs to achieve certain functionality; for example, a small amount of light calcium carbonate aqueous dispersion can be added to play a nucleating role, making the foam structure more uniform and delicate. DETAILED DESCRIPTION

[0023] The present invention is further described below in conjunction with specific embodiments. The described embodiments are only a part of the embodiments of the present invention, but not all of the embodiments.

[0024] Table 1 List of raw materials

[0025]

[0026] [Example 1]

[0027] 19 parts of TDI, 25 parts of PEG2000, 26 parts of CHE-3602, 20 parts of ED-28 and 10 parts of 330N were added into a three-necked flask, stirred evenly and heated to 75°C, reacted for 2 hours to obtain sample B1, and the NCO value was measured to be 6.71;

[0028] Weigh 50 g of purified water, add 50 g of prepolymer B1, mix quickly (laboratory stirrer 5CM rotor 2000 revolutions for 5 seconds), and pour into a cup to obtain a low-odor polyurethane foam material.

[0029] The performance test data of the prepared low-odor polyurethane foam material are shown in Table 3.

[0030] [Examples 2 to 4]

[0031] The steps of Examples 2 to 4 are consistent with those of Example 1 to obtain corresponding B2 to B4. The raw material components and raw materials are shown in Table 2. The performance test data of the obtained low-odor polyurethane foam material is shown in Table 3.

[0032] [Comparative Example 1]

[0033] 80 parts of MI and 20 parts of MM103 were mixed evenly to obtain sample B5, and the measured NCO value was 36.70.

[0034] Sample A1 was obtained by mixing 73.5 parts of CHE-330N, 20 parts of CHED-28, 2.5 parts of diethylene glycol, 1.5 parts of Tegostab B8734 LF2, 0.6 parts of Jeffcat LE-530, and 2.0 parts of water.

[0035] 100 parts of A1 and 45 parts of B5 were weighed and mixed with rapid stirring (laboratory stirrer 5CM rotor 1500 rpm for 10 seconds) to obtain Comparative Example 1.

[0036] The performance test data of the prepared polyurethane foam material are shown in Table 3.

[0037] [Comparative Example 2]

[0038] 73.5 parts of CHE-330N, 20 parts of CHED-28, 2.5 parts of diethylene glycol, 1.5 parts of Tegostab B8715, 0.4 parts of Dabco 33LV, 0.2 parts of Jeffcat 5, and 2.0 parts of water were mixed to obtain sample A2.

[0039] 100 parts of A2 and 45 parts of B5 obtained in Comparative Example 1 were mixed and stirred rapidly (laboratory stirrer 5CM rotor 1500 rpm for 10 seconds) to obtain Comparative Example 2.

[0040] The performance test data of the prepared polyurethane foam material are shown in Table 3.

[0041] Table 2 Raw material components of low odor polyurethane foam materials prepared in Examples 1 to 4

[0042]

[0043]

[0044] Table 3 Performance test data of polyurethane foam materials of Examples 1 to 4 and Comparative Examples 1 to 2

[0045] Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 <![CDATA[Density kg / m 3 > 46.3 61.4 62.7 78.6 61.8 60.79 Tensile strength MPa 0.180 0.201 0.285 0.259 0.111 0.106 Elongation at break % 182 272 241 305 102 82.1 Tear strength N / mm 0.226 0.273 0.318 0.331 0.165 0.148 Odor test results 3.0 3.5- 3.5- 3.0 3.5 4.5

[0046] The low-odor polyurethane foam of the present invention has a strong advantage in odor over traditional foams because it adopts a prepolymer process route and eliminates the use of silicone oil and catalyst in the formula system.

[0047] According to the test results, the low-odor foam of the present invention has better strength performance in tensile and tear strength than ordinary foams because the prepolymer method is adopted in the process.

Claims

1. A low-odor polyurethane foam material, consisting of component A and component B, wherein the weight ratio of component A to component B is 0.3 to 3:1, wherein: Component A is selected from water or water dispersion; component B comprises, by weight: 60 to 95 parts of hydrophilic polyether polyol and 5 to 40 parts of isocyanic acid.

2. The low-odor polyurethane foam material according to claim 1, characterized in that: The molecular weight of the hydrophilic polyether polyol is 100-3000, and the functionality is 2-3; the isocyanic acid is selected from at least one isocyanic acid monomer.

3. The low-odor polyurethane foam material according to claim 1, characterized in that: The aqueous dispersion is selected from a polymer aqueous dispersion with a solid content of 2 to 60%, an inorganic aqueous dispersion or an aqueous dispersion with functional additives added.

4. The low-odor polyurethane foam material according to claim 2, characterized in that: The hydrophilic polyether polyol is selected from at least one of PEG-2000, CHE-L64, CHE-2070E, CHED-28, CHE-330N, CHE-3602, and CHE-608; the isocyanate monomer is selected from at least one of HDI, IPDI, H12MDI, XDI, MDI, TDI, MI, biuret, or trimer.

5. The low-odor polyurethane foam material according to claim 3, characterized in that: The aqueous dispersion is composed of water and water-dispersible substances, the solid content of which is in the range of 2-60%, and the water-dispersible substances are selected from at least one of low-odor acrylic emulsion, polyvinyl alcohol emulsion, EVA emulsion, natural latex, styrene-butadiene latex, wax emulsion, diethylene glycol or calcium carbonate.

6. The low-odor polyurethane foam material according to claim 1, characterized in that: The weight ratio of component A to component B is 0.3-2:

1.

7. A method for preparing the low-odor polyurethane foam material according to claim 1, comprising the following steps: (1) Preparation of component B: 60-95 parts of hydrophilic polyether polyol and 5-40 parts of isocyanic acid are added to a reaction kettle, heated to 75-80° C., kept warm for 1-2 hours, and cooled to obtain component B; (2) Component A and component B are uniformly mixed in a weight ratio of 0.3 to 3:1 to obtain a low-odor polyurethane foam material.

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