All-water foaming organic silicon polyurethane foam material and preparation method thereof

Abstract

The invention discloses an all-water foaming organic silicon polyurethane foam material and a preparation method thereof. The organic silicon polyurethane foam material is composed of a component A and a component B, the component A comprises a polyether grafted polysiloxane (polyether block) copolymer, water, a catalyst and a foam stabilizer; the component B is isocyanate; the preparation method comprises the following steps: uniformly stirring and mixing a component A and a component B, freely foaming to form a crude product, and curing and curing the crude product to obtain the all-water foaming organic silicon polyurethane foam material, the organic silicon polyurethane foam material prepared by adopting an all-water foaming technology is high in organic silicon component content, green, environment-friendly, simple in process, low in cost, relatively low in odor in the foaming process, excellent in performance, uniform and defect-free in foam pores, high in tensile strength and tearing strength of foam, excellent in elongation at break, large in water contact angle and excellent in hydrophobicity.

Description

Technical Field

[0001] The present invention relates to a fully water - blown organosilicon polyurethane foam material and a preparation method thereof, belonging to the cross - technical field of polyurethane foam materials and organosilicon polymer materials. Background Art

[0002] When preparing polyurethane foam materials, two major types of foaming agents are usually used: physical foaming agents and chemical foaming agents. The chemical foaming agent is water, which reacts with isocyanate to generate carbon dioxide, and the carbon dioxide gas plays a foaming role; physical foaming agents are generally low - boiling fluorinated hydrocarbons or hydrocarbon compounds, and the gas generated by vaporization due to the exothermic reaction of the reaction system is used to initiate foaming. Commonly used physical foaming agents, such as halogenated fluorochlorohydrocarbon foaming agents like HCFC - 141b and low - boiling solvents like cyclopentane, during use, the volatilization of the foaming agent will damage the ozone layer and at the same time have a high VOC value, causing a series of environmental problems. In contrast, water is the most ideal foaming agent, with an ODP value of zero and no generation of other volatile organic compounds, and the preparation process is green and environmentally friendly. With people's attention and emphasis on green and environmentally friendly materials, fully water - blown polyurethane materials are gradually coming into people's view.

[0003] At present, the preparation technology of fully water - blown polyurethane foam materials has been relatively mature, but there are still some problems. Without the dilution effect of physical foaming agents, the system has a high viscosity and poor fluidity; due to the hydrogen - bond effect of water molecules and the generally poor solubility of water in polyols, the foaming material is prone to local over - reaction and foaming, resulting in uneven cell distribution and size; when water reacts with isocyanate, a large amount of heat is released, easily causing the core temperature of the foam to be too high and resulting in the phenomenon of core burning; too much water content is likely to cause defects such as brittle foam and poor adhesion to the substrate.

[0004] Organosilicon polymer materials, due to their unique semi - inorganic and semi - organic structure, have excellent properties such as resistance to high and low temperatures, low surface energy, excellent thermal stability, water repellency, electrical insulation, and physiological inertness. Polyurethane foam materials have advantages such as low density, light weight, low thermal conductivity, good buffering performance, sound absorption and heat insulation, and are widely used in fields such as aerospace, military, transportation, packaging and construction, sports goods, and clothing and footwear. However, traditional polyurethane foam materials have some defects and deficiencies, such as poor resistance to high and low temperatures, poor weather resistance and water resistance, etc. Therefore, introducing organosilicon components into polyurethane foam materials to endow polyurethane foam materials with the excellent properties of organosilicon polymers is a current research hotspot in the polyurethane field.

[0005] The patent document with the authorization announcement number CN 114805730 B discloses an organosilicon polyurethane foam preparation, a polyether-grafted polysiloxane polyether block copolymer and its preparation method, which introduces an organosilicon component into the polyurethane foam material to prepare an organosilicon polyurethane foam. However, due to the hydrophobicity of the organosilicon polymer, this technology still uses the traditional foaming process of polyurethane foam, generally using a physical foaming agent and a chemical foaming agent at the same time. If the physical foaming agent is not used, the mechanical properties of the foam will be affected (see its Example 1 for details), and its use value is not high. In this system, the physical foaming agent not only generates gas by heating and vaporization to initiate foaming, but also serves as a solvent for the material system, playing a role in regulating the compatibility of each component of the foaming system. However, the volatilization of the physical foaming agent will damage the ozone layer, leading to many environmental problems. Therefore, the all-water foaming technology without using a physical foaming agent is also the development trend of the organosilicon polyurethane foaming industry. In addition, this technology also has the problem of excessive catalyst dosage, and the catalyst remaining in the foam will have a certain negative impact on the color and odor of the foam. In addition, the dosage of the foam stabilizer in this technology is also relatively large, and the foam stabilizer cannot play its role efficiently. Therefore, it is necessary to upgrade the technology on the basis of the authorized patent technology, develop an all-water organosilicon polyurethane foaming technology that completely eliminates the physical foaming agent, uses less catalyst and foam stabilizer, and is more environmentally friendly. On this basis, it is also necessary to further improve the existing performance indicators of the organosilicon polyurethane foam.

[0006] Silicone polyurethane foam materials are prepared by reacting silicone polyols and isocyanates as the main raw materials, and the foam skeleton is mainly composed of silicone polyurethane. However, at present, there are few related technologies for silicone polyurethane foam materials. Most of them are to modify the surface of the prepared traditional polyurethane foam materials with silicone linkages, and the proportion of silicone components is low. There are few published literatures on the all-water foaming technology of silicone polyurethane. Due to the hydrophobic property of silicone polymers, their compatibility with water is poor. The formulation needs to contain a physical foaming agent, which is necessary for foaming and also acts as a solvent to improve the compatibility of each component in the system. Therefore, the technical difficulty of all-water foaming of silicone polyurethane is relatively large. For example, Liu et al. constructed a magnetic polydopamine coating and a branched polydimethylsiloxane molecular brush coating on the surface of commercial melamine foam substrates through dopamine rapid co-deposition technology and surface atom transfer radical polymerization method to obtain a superhydrophobic oil-water separation foam material (see the literature "Y. Liu, X. Wang, S. Feng, Nonflammable and Magnetic Sponge Decorated with Polydimethylsiloxane Brush for Multitasking and Highly Efficient Oil–Water Separation[J]. Advanced Functional Materials, 2019, 29, 1902488."). However, the obtained foam material has a low silicone content and only modifies the surface of the foam substrate with silicone. Zhang et al. improved the hydrophobicity of polyurethane foam by methods such as chromic acid etching and fluoroalkylsilane chemical modification. Chromic acid etching increased the roughness of the foam surface, and the introduction of low-surface-energy fluoroalkylsilane improved the hydrophobicity of the foam (see the literature "Zhang X, Li Z, Liu K, et al. Bioinspired multifunctional foam with self-cleaning and oil / water separation[J]. Advanced Functional Materials, 2013, 23(22): 2881-2886."). The polyurethane foam prepared in this literature also only modifies the surface of the polyurethane foam material with silicone. The patent document with the publication number CN119431715A describes a method of obtaining component A mainly composed of polyether polyol and a polyorganosiloxane-polyurethane prepolymer capped with isocyanate of component B through a negative pressure technique. After mixing components A and B, they are foamed and potted to obtain a silicone-polyurethane foam potting material. However, the preparation process of this material is complex and the silicone content is low.The patent document with the publication number CN 107652411 A discloses an organosilicon-modified polyurethane foam, which is prepared by a one-pot method using hydroxyl-terminated fluorosilicone oil, polyester polyol and diisocyanate. However, the organosilicon component introduced by this method is not high, and a physical foaming agent is also used, and the all-water foaming technology is not achieved. Summary of the Invention

[0007] The present invention provides an all-water foaming organosilicon polyurethane foam material and a preparation method thereof. By using a polyether grafted polysiloxane (polyether block) copolymer and only using water as a foaming agent, it is not only green and environmentally friendly, but also has obvious improvement in performance compared with the foam obtained by using physical foaming agents and chemical foaming agents. Especially the tensile strength breaks through 300 kPa, and the tear strength breaks through 550 N / m. While the tensile and tear strengths are improved, other properties of the foam are maintained, such as softness, water repellency, elongation at break, etc.

[0008] The all-water foaming organosilicon polyurethane foam material is composed of component A and component B, wherein:

[0009] Component A includes:

[0010] (a) A polyether grafted polysiloxane (polyether block) copolymer

[0011] The polyether grafted polysiloxane (polyether block) copolymer has the structure shown in Formula I-1 or Formula I-2:

[0012] Wherein:

[0013] Each time it appears, m can be the same or different, and is in the range of 20-85, preferably in the range of 30-65.

[0014] Each time it appears, n can be the same or different, and is in the range of 3-13, preferably in the range of 5-10.

[0015] Each time it appears, a can be the same or different, and is an integer from 0 to 8, preferably an integer from 2 to 5.

[0016] Each time it appears, b can be the same or different, and is an integer from 4 to 16, preferably an integer from 8 to 12.

[0017] The preparation method of the above polyether grafted polysiloxane (polyether block) copolymer with Formula I-1 and Formula I-2 is the same as the corresponding preparation method disclosed in the patent document with the authorization announcement number CN 114805730 B.

[0018] The molecular weight range of the polyether grafted polysiloxane (polyether block) copolymer of this patent is small, avoiding the adverse effect on the foam foaming process caused by the too high viscosity of the high molecular weight polyether grafted polysiloxane (polyether block) copolymer. During the foaming process, if the viscosity of the material is too high, it is difficult for carbon dioxide gas to escape, which easily leads to many closed cells and uneven cell structure in the foam, and the success rate of all-water foaming is low. Therefore, in order to achieve the goal of all-water foaming in this patent, the molecular weight of the polyether grafted polysiloxane (polyether block) copolymer is reduced.

[0019] (b) Blowing agent

[0020] Only the chemical blowing agent water is selected as the blowing agent. Based on 100 parts by weight of the (a) polyether grafted polysiloxane (polyether block) copolymer, the amount of water used is 0.5 - 6 parts by weight.

[0021] The amount of the chemical blowing agent water has a great influence on the foam. At the same time, during the preparation of all-water foamed silicone polyurethane foam, different from the preparation of traditional foams, especially without the dilution effect of physical blowing agents, it is more difficult to prepare the foam. Water can consume a large amount of isocyanate and generate a large amount of gas and heat at the same time. The increase of the blowing agent water in the reaction system can accelerate the speed of the foaming reaction. In this patent, if the amount of water used exceeds the upper limit of 6 parts by weight protected by this patent (based on 100 parts by weight of the (a) polyether grafted polysiloxane (polyether block) copolymer, the same below), although there are more urea groups generated in the polymer, providing mechanical strength for the foam, the foam texture is hard and brittle, and the reaction is violent. Without a physical blowing agent to remove the reaction heat, there may even be a phenomenon of foam core burning and cracking. In addition, the increase in the amount of water used will lead to an increase in the amount of carbon dioxide gas generated, thereby making the cell size of the foam larger, forming a larger pore structure, and this structural defect will significantly reduce the mechanical properties of the foam.

[0022] (c) Catalyst

[0023] Based on 100 parts by weight of the polyether grafted polysiloxane (polyether block) copolymer, the amount of the (c) catalyst used is 0.1 - 0.8 parts by weight.

[0024] In the production of all-water blown silicone polyurethane foam, the catalysts are mainly tertiary amine catalysts and organotin catalysts. Tertiary amine catalysts are beneficial to the reaction between the blowing agent water and isocyanate, that is, the foaming reaction; organotin catalysts are beneficial to the reaction between hydroxyl groups and isocyanate, that is, the gel reaction. Therefore, controlling the ratio of amine-tin catalysts can control the rates of the foaming reaction and the gel reaction. Without the dilution effect of a physical blowing agent, too much organotin catalyst can easily cause carbon dioxide gas to be difficult to escape, resulting in many closed cells and uneven cell sizes in the foam, and a low success rate of all-water blowing. Therefore, there is an optimal dosage range for the mass ratio of the mixed amine-tin catalysts, and the mass ratio of the tertiary amine catalyst to the organotin catalyst is 1:0.5 - 3.

[0025] Preferably, the tertiary amine catalyst is any one of triethylenediamine, N,N-dimethylcyclohexylamine, triethanolamine, and triethylamine.

[0026] Preferably, the organotin catalyst is any one of stannous octoate, dibutyltin dilaurate, dibutyltin diacetate, and dibutyltin mercaptide.

[0027] (d) Foam stabilizer

[0028] Based on 100 parts by weight of the polyether grafted polysiloxane (polyether block) copolymer, the dosage of (d) foam stabilizer is 0.1 - 0.8 parts by weight.

[0029] The foam stabilizer is indispensable in the production of foam, playing the roles of emulsifying the foam materials, stabilizing the foam, and regulating the cell structure. Currently, most of the used foam stabilizers belong to silicone surfactants, and the main structure is a polysiloxane-oxyalkylene block copolymer. The foam stabilizer can increase the mutual solubility of each component of the raw materials, contribute to the formation of bubbles, control the size and uniformity of the cells, make the cell walls elastic to retain gas, and prevent the foam from collapsing. In this patent, when the dosage of the foam stabilizer is lower than the lower limit of protection of this patent, 0.1 part by weight, the foam pore size is larger, the foam wall is thinner, and the mechanical properties of the foam are lower; when the dosage of the foam stabilizer is higher than the upper limit of protection of this patent, 0.8 part by weight, it will cause the bubble film wall to be too thin, and the strength is insufficient to withstand the tension of the foam, easily causing the bubble film wall to rupture, and ultimately resulting in foam collapse. Therefore, the foam stabilizer is 0.1 - 0.8 parts by weight.

[0030] Preferably, the foam stabilizer is a silicone surfactant and can be any one of the commonly used foam stabilizers in the art.

[0031] (e) Chain extender and crosslinking agent

[0032] Based on 100 parts by weight of the polyether grafted polysiloxane (polyether block) copolymer, the dosage of (e) chain extender and crosslinking agent is 0 - 6 parts by weight, preferably 2 - 4 parts by weight.

[0033] Preferably, the chain extender and crosslinking agent are any one of 1,4-butanediol, ethylene glycol, propylene glycol, and a silicon-based chain extender. The silicon-based chain extender has the structure shown in Formula II:

[0034] Among them, R can be the same or different.

[0035] For the above-mentioned silicon-based chain extender used, where:

[0036] R = -CH 2 CH 2 CH 2 OH, the silicon-based chain extender is 1,3-bis(3-hydroxypropyl)-1,1,3,3-tetramethyldisiloxane, that is, hydroxypropyl double-ended cap; R = -CH 2 CH 2 CH 2 NH 2 When it is, the silicon-based chain extender is 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane, that is, aminopropyl double-ended cap, and both can be directly purchased.

[0037] The chain extender and crosslinking agent can improve and regulate the properties of polyurethane foam. Because of their small molecular weight and short chain segments, increasing the dosage within a certain range can increase the glass transition temperature, hardness, and tensile strength of the polymer, but the resilience and softness will decrease. Compared with carbon-based chain extenders, the silicon-based chain extender has less chain segment rigidity and better compatibility with polyether grafted polysiloxane, and maintains the resilience and softness of the foam while improving the foam properties.

[0038] Component B is an isocyanate. Based on 100 parts by weight of the polyether grafted polysiloxane (polyether block) copolymer, the dosage of component B is determined according to the equivalent ratio of the isocyanate groups of the isocyanate and the hydroxyl groups of component A. The equivalent ratio of the isocyanate groups of the isocyanate and the hydroxyl groups of component A is 0.8 - 1.2:1, preferably 0.9 - 1.1:1. Preferably, the isocyanate is any one or more of MDI-50 (a mixture of 2,4-diphenylmethane diisocyanate and 4,4'-diphenylmethane diisocyanate), liquefied MDI, polymeric MDI, and HMDI (dicyclohexylmethane diisocyanate).

[0039] The present invention provides a preparation method for the above-mentioned all-water foaming organosilicon polyurethane foam material, which specifically includes the following steps:

[0040] (1) Weigh each component according to the weight ratio;

[0041] (2) Mix component A and stir evenly to obtain a component A mixture;

[0042] (3) Add component B to the mixture in step (2) and stir to mix evenly.

[0043] (4) Pour the well-stirred raw materials in step (3) quickly into a mold for free foaming to form a crude foam, and cure the crude product to obtain a fully water-blown organosilicon polyurethane foam material.

[0044] Preferably, all stirring operations use a mechanical stirring device. The stirring speed in step (2) is ≥600 r / min and the stirring time is 60 - 180 s; the stirring speed in step (3) is ≥1000 r / min and the stirring time is 10 - 15 s.

[0045] Preferably, the foaming time is ≤2 min.

[0046] Preferably, the curing temperature is 70 °C and the curing time is 30 - 60 min.

[0047] Preferably, the mold is made of polytetrafluoroethylene, and the inner surface of the mold is smooth, which is beneficial to demolding.

[0048] The preparation process of the polyurethane foam includes two reaction processes: (i) The reaction of isocyanate with water releases carbon dioxide, and the heat released by the reaction of isocyanate with polyol compounds vaporizes the physical blowing agent (low-boiling solvent) to generate gas. This is the foaming reaction. (ii) The reaction of isocyanate with polyol compounds generates urethane to obtain a crosslinked network structure. This is the gel reaction. In addition, the reaction of isocyanate with water to form urea and the crosslinking reaction with the chain extender also belong to the gel reaction. During the foaming process of the polyurethane foam, the reaction of isocyanate with water generates carbon dioxide, or the physical blowing agent in the system is vaporized by heat, thereby increasing the gas volume in the reaction system. These generated gases diffuse into the bubbles through the liquid phase, causing the foam volume to increase, and at the same time, the liquid phase surrounding the bubbles becomes thinner. As the polymer liquid phase further thins, the bubbles gradually lose their original spherical structure and become a planar form composed of polymer films. Finally, under the action of surface tension, an open microporous structure with a network structure is formed.

[0049] During the synthesis of polyurethane foam, the balance between the foaming reaction rate and the gel reaction rate is crucial. In the present invention, the amount of water as a chemical blowing agent and the amount of tertiary amine catalysts directly affect the foaming reaction rate, while the amount of organotin catalysts mainly determines the gel reaction rate. The molecular weight and functionality of polyol compounds not only directly affect the foaming reaction rate but also influence the viscosity of the material. Too low viscosity may cause gas to break through the foam wall too quickly, while too high viscosity may impede gas diffusion, thus indirectly affecting the foaming reaction. At the same time, the molecular weight and functionality of polyol compounds are also closely related to the strength of the foam wall. The foam stabilizer ensures the stability of the foaming process by emulsifying the material and regulating the surface tension of the system, ultimately obtaining a foam with uniform cell structure and high elasticity. The amounts of chain extender and crosslinking agent also affect the foaming reaction rate and, by adjusting the crosslinking density of the foam body, further affect the properties and morphology of the foam. Therefore, the preparation process of polyurethane foam is the result of the combined action of various components, and it is necessary to precisely adjust the ratio of each component to ensure the balance between the foaming reaction rate and the gel reaction rate, so as to optimize the properties and morphology of the foam.

[0050] The present invention also provides the use of the above-mentioned all-water-blown organosilicon polyurethane foam materials in the preparation of polyurethane flexible foams for various applications, including household products, shock-absorbing and cushioning materials, sound-absorbing and sound-insulating materials, automotive interiors, packaging and thermal insulation materials, moisture-proof and waterproof materials, and oil-water separation materials.

[0051] The present invention uses an all-water-blown technology to prepare organosilicon polyurethane foam materials, which have a high content of organosilicon components, are green and environmentally friendly, have a simple process, low cost, a relatively low odor during the foaming process, and excellent properties. The foam has uniform cell structure and no defects, with a high tensile strength (190 - 340 kPa), a high tear strength (370 - 580 N / m), an excellent elongation at break (70 - 110%), and a large water contact angle (120 - 140°), showing excellent hydrophobicity. The mechanical properties of the foam, especially the tensile and tear strengths of the foam, are significantly improved through the synergistic effect with other components without the use of physical blowing agents and with a reduced amount of water as a chemical blowing agent, while still maintaining its elongation at break and hydrophobic properties, expanding the application range of the foam, having a high recyclability, and conforming to the concept of sustainable development. Detailed Embodiments

[0052] Example 1

[0053] Take 100 parts (by weight) of a polyether-grafted polysiloxane (polyether block) copolymer with the structural formula Ⅰ-1 (molecular weight about 5400 g / mol), 2 parts of water, 0.1 part of triethylenediamine, 0.3 part of stannous isooctanoate, and 0.3 part of foam stabilizer and add them into a polytetrafluoroethylene beaker. Use a high-speed stirrer to mix the above components evenly. Subsequently, measure and add MDI-50 (the equivalent ratio of isocyanate groups to hydroxyl groups is 0.8:1) to this mixture, and stir with a high-speed stirrer for 10 s. Immediately transfer the mixture to a mold, let it stand for 2 min, and then transfer it to an oven at 70 °C for curing for 30 min. After a demolding time of 30 min, a fully water-blown silicone polyurethane foam with uniform and defect-free cells is obtained. The tensile strength of the foam is 195.16 kPa, the tear strength is 376.34 N / m, the elongation at break is 105.06%, and the apparent density is 113.4 kg / m 3 , the water contact angle θ = 134.47°, and the silicone polyurethane foam is hydrophobic.

[0054] Example 2

[0055] Take 100 parts (by weight) of a polyether-grafted polysiloxane (polyether block) copolymer with the structural formula Ⅰ-1 (molecular weight about 7300 g / mol), 3 parts of water, 0.1 part of triethylamine, 0.05 part of stannous isooctanoate, 0.2 part of foam stabilizer, and 3 parts of 1,4-butanediol and add them into a polytetrafluoroethylene beaker. Use a high-speed stirrer to mix the above components evenly. Subsequently, measure and add HMDI (the equivalent ratio of isocyanate groups to hydroxyl groups is 1.05:1) to this mixture, and stir with a high-speed stirrer for 10 s. Immediately transfer the mixture to a mold, let it stand for 2 min, and then transfer it to an oven at 70 °C for curing for 30 min. After a demolding time of 20 min, a fully water-blown silicone polyurethane foam with uniform and defect-free cells is obtained. The tensile strength of the foam is 245.96 kPa, the tear strength is 436.54 N / m, the elongation at break is 76.36%, and the apparent density is 79.62 kg / m 3 , the water contact angle θ = 130.51°, and the silicone polyurethane foam is hydrophobic.

[0056] Example 3

[0057] Take 100 parts (by weight) of a polyether-grafted polysiloxane (polyether block) copolymer with the structural formula Ⅰ-2 (molecular weight about 11000 g / mol), 2 parts of water, 0.1 part of triethylenediamine, 0.2 part of dibutyltin dilaurate, 0.4 part of a foam stabilizer, and 5 parts of a silicone chain extender and add them to a polytetrafluoroethylene beaker. Use a high-speed stirrer to mix the above components evenly. Subsequently, add the metered liquefied MDI (the equivalent ratio of isocyanate groups to hydroxyl groups is 1.2:1) to this mixture and stir with a high-speed stirrer for 10 s. Immediately transfer the mixture to a mold, let it stand for 2 min, and then transfer it to an oven at 70 °C for curing for 50 min. After a demolding time of 30 min, a fully water-blown silicone polyurethane foam with uniform and defect-free cells is obtained. The tensile strength of the foam is 239.21 kPa, the tear strength is 413.78 N / m, the elongation at break is 80.34%, and the apparent density is 218.12 kg / m 3 , the water contact angle θ = 122.67°, and the silicone polyurethane foam is hydrophobic.

[0058] Example 4

[0059] Take 100 parts (by weight) of a polyether-grafted polysiloxane (polyether block) copolymer with the structural formula Ⅰ-2 (molecular weight about 13300 g / mol), 5 parts of water, 0.15 part of triethanolamine, 0.45 part of stannous isooctanoate, 0.6 part of a foam stabilizer, and 2 parts of 1,4-butanediol and add them to a polytetrafluoroethylene beaker. Use a high-speed stirrer to mix the above components evenly. Subsequently, add the metered MDI-50 (the equivalent ratio of isocyanate groups to hydroxyl groups is 0.9:1) to this mixture and stir with a high-speed stirrer for 10 s. Immediately transfer the mixture to a mold, let it stand for 2 min, and then transfer it to an oven at 70 °C for curing for 50 min. After a demolding time of 30 min, a fully water-blown silicone polyurethane foam with uniform and defect-free cells is obtained. The tensile strength of the foam is 295.92 kPa, the tear strength is 523.34 N / m, the elongation at break is 79.15%, and the apparent density is 228.12 kg / m 3 , the water contact angle θ = 125.23°, and the silicone polyurethane foam is hydrophobic.

[0060] Example 5

[0061] Take 100 parts (by weight) of a polyether-grafted polysiloxane (polyether block) copolymer with the structural formula Ⅰ-1 (molecular weight about 10,500 g / mol), 2.5 parts of water, 0.15 part of triethylenediamine, 0.1 part of mercaptodibutyltin, 0.6 part of foam stabilizer, and 3 parts of a silicon-based chain extender and add them to a polytetrafluoroethylene beaker. Use a high-speed stirrer to mix the above components evenly. Subsequently, add the metered polymeric MDI (the equivalent ratio of isocyanate groups to hydroxyl groups is 1:1) to this mixture and stir with a high-speed stirrer for 10 s. Immediately transfer the mixture to a mold, let it stand for 2 min, and then transfer it to an oven at 70 °C for curing for 50 min. After a demolding time of 30 min, a fully water-blown silicone polyurethane foam with uniform and defect-free cells is obtained. The tensile strength of the foam is 270.12 kPa, the tear strength is 457.88 N / m, the elongation at break is 79.46%, and the apparent density is 210.23 kg / m 3 , the water contact angle θ = 133.50°, and the silicone polyurethane foam is hydrophobic.

[0062] Example 6

[0063] Take 100 parts (by weight) of a polyether-grafted polysiloxane (polyether block) copolymer with the structural formula Ⅰ-2 (molecular weight about 9,300 g / mol), 1.5 parts of water, 0.15 part of N,N-dimethylcyclohexylamine, 0.45 part of dibutyltin diacetate, 0.6 part of foam stabilizer, and 2 parts of propylene glycol and add them to a polytetrafluoroethylene beaker. Use a high-speed stirrer to mix the above components evenly. Subsequently, add the metered MDI-50 (the equivalent ratio of isocyanate groups to hydroxyl groups is 1.15:1) to this mixture and stir with a high-speed stirrer for 10 s. Immediately transfer the mixture to a mold, let it stand for 2 min, and then transfer it to an oven at 70 °C for curing for 50 min. After a demolding time of 30 min, a fully water-blown silicone polyurethane foam with uniform and defect-free cells is obtained. The tensile strength of the foam is 232.42 kPa, the tear strength is 392.67 N / m, the elongation at break is 105.41%, and the apparent density is 128.93 kg / m 3 , the water contact angle θ = 129.83°, and the silicone polyurethane foam is hydrophobic.

[0064] Comparative Example 1

[0065] Using 100 parts of a polyether grafted polysiloxane (polyether block) copolymer with the structural formula Ⅰ-1 (molecular weight about 5400 g / mol), 0.1 part of triethylenediamine, 0.3 part of stannous isooctanoate, and 0.3 part of a foam stabilizer used in Example 1, 8 parts of water was selected as the chemical blowing agent and added to a polytetrafluoroethylene beaker, and the above components were mixed evenly with a high-speed stirrer. Subsequently, the measured MDI-50 (equivalent ratio of isocyanate groups to hydroxyl groups is 0.8:1) was added to the mixture, and it was stirred with a high-speed stirrer for 10 s. The mixture was immediately transferred to a mold, left standing for 2 min and then transferred to an oven at 70 °C for curing for 30 min. After a demolding time of 30 min, the obtained all-water foamed silicone polyurethane foam had coarse pores, brittle foam, and large defects due to excessive water usage. The tensile strength was 128.32 kPa, the tear strength was 264.37 N / m, the elongation at break was 40.54%, and the apparent density was 53.78 kg / m 3 , and the water contact angle θ = 101.54°.

[0066] Comparative Example 2

[0067] Using 100 parts of a polyether grafted polysiloxane (polyether block) copolymer with the structural formula Ⅰ-1 (molecular weight about 7300 g / mol), 3 parts of water, 0.2 part of a foam stabilizer, and 3 parts of 1,4-butanediol used in Example 2, 1 part of triethylamine and 3 parts of stannous isooctanoate were selected as the catalysts and added to a polytetrafluoroethylene beaker, and the above components were mixed evenly with a high-speed stirrer. Subsequently, the measured HMDI (equivalent ratio of isocyanate groups to hydroxyl groups is 1.05:1) was added to the mixture, and it was stirred with a high-speed stirrer for 10 s. The mixture was immediately transferred to a mold, left standing for 2 min and then transferred to an oven at 70 °C for curing for 30 min. After a demolding time of 20 min, the obtained all-water foamed silicone polyurethane foam had severe shrinkage and many closed cells due to excessive catalyst usage. The tensile strength was 164.17 kPa, the tear strength was 357.84 N / m, the elongation at break was 51.87%, and the apparent density was 167.68 kg / m 3 , and the water contact angle θ = 127.54°.

[0068] Comparative Example 3

[0069] Using 100 parts of the polyether grafted polysiloxane (polyether block) copolymer with the structural formula Ⅰ-2 (molecular weight about 11,000 g / mol), 2 parts of water, 0.1 part of triethylenediamine, 0.2 part of dibutyltin dilaurate, and 5 parts of a silicon-based chain extender used in Example 3, 5 parts of a foam stabilizer were selected and added to a polytetrafluoroethylene beaker, and the above components were mixed evenly with a high-speed stirrer. Subsequently, the measured liquefied MDI (equivalent ratio of isocyanate groups to hydroxyl groups is 1.2:1) was added to the mixture, and it was stirred with a high-speed stirrer for 10 s. The mixture was immediately transferred to a mold, left standing for 2 min and then transferred to an oven at 70 °C for curing for 50 min. After a demolding time of 30 min, the obtained all-water foamed silicone polyurethane foam had serious shrinkage due to excessive foam stabilizer, many closed cells in the foam, a tensile strength of 169.95 kPa, a tear strength of 308.25 N / m, an elongation at break of 46.38%, and an apparent density of 275.23 kg / m 3 , and the water contact angle θ = 121.39°.

[0070] By comparing Example 1 with Comparative Example 1, Example 2 with Comparative Example 2, and Example 3 with Comparative Example 3, it can be clearly seen that the foam has high tensile and tear strengths, excellent elongation at break, a large water contact angle, and excellent hydrophobicity. Especially for the tensile and tear strengths, without the use of a physical blowing agent and with a reduced amount of the chemical blowing agent water, a significant improvement has been achieved compared with the previous technologies. The dosage ratios of the components in this patent give full play to the synergistic effects of the components. In particular, the dosages of the chemical blowing agent water, catalyst, and foam stabilizer have a significant impact on the morphology and properties of the foam, thus enabling the morphology and properties of the foam to reach the optimal state.

[0071] The above embodiments do not limit the present invention in any way. All technical solutions obtained by using equivalent substitution or equivalent transformation fall within the protection scope of the present invention.

Claims

1. Fully water-foamed silicone polyurethane foam material, characterized in that It consists of component A and component B, wherein: The component A comprises: (a) Polyether grafted polysiloxane (polyether block) copolymer The polyether grafted polysiloxane (polyether block) copolymer has a structure shown in Formula Ⅰ-1 or Formula Ⅰ-2: in: In each occurrence, m can be the same or different and is in the range of 20-85; In each occurrence, n can be the same or different and range from 3 to 13; In each occurrence, a can be the same or different and is an integer from 0 to 8; In each occurrence, b can be the same or different and is an integer from 4 to 16; (b) Foaming agent The foaming agent is water, and the amount of the foaming agent is 0.5-6 parts by weight based on 100 parts by weight of the polyether grafted polysiloxane (polyether block) copolymer; (c) Catalyst Based on 100 parts by weight of the polyether grafted polysiloxane (polyether block) copolymer, the amount of the catalyst is 0.1-0.8 parts by weight; (d) Foam stabilizer Based on 100 parts by weight of the polyether grafted polysiloxane (polyether block) copolymer, the amount of the foam stabilizer is 0.1-0.8 parts by weight; The component B is an isocyanate. The amount of the component B is determined according to the equivalent ratio of the isocyanate group of the isocyanate to the hydroxyl group of the component A based on 100 parts by weight of the polyether-grafted polysiloxane (polyether block) copolymer. The equivalent ratio of the isocyanate group of the isocyanate to the hydroxyl group of the component A is 0.8-1.2:

1.

2. The fully water-foamed silicone polyurethane foam material according to claim 1, characterized in that: The catalyst is a tertiary amine catalyst and an organic metal tin catalyst, and the mass ratio of the tertiary amine catalyst to the organic metal tin catalyst is 1:0.5-3.

3. The fully water-foamed silicone polyurethane foam material according to claim 1, characterized in that: The component A also includes a chain extender and a crosslinker. The amount of the chain extender and the crosslinker is within 6 parts by weight based on 100 parts by weight of the polyether grafted polysiloxane (polyether block) copolymer.

4. The fully water-foamed organosilicon polyurethane foam material according to claim 3, characterized in that: The chain extender and cross-linking agent are any one of 1,4-butanediol, ethylene glycol, propylene glycol, and a silicon-based chain extender.

5. The fully water-foamed silicone polyurethane foam material according to claim 4, characterized in that: The chain extender and cross-linking agent are silicon-based chain extenders, and the silicon-based chain extender has a structure shown in formula II: Here, R may be the same or different.

6. The fully water-foamed silicone polyurethane foam material according to claim 1, characterized in that: The isocyanate is any one or more of MDI-50, liquefied MDI, polymeric MDI and HMDI.

7. The method for preparing the fully water-foamed organosilicon polyurethane foam material according to any one of claims 1 to 6, characterized in that The following steps are involved: (1) Weigh each component according to weight ratio; (2) mixing component A and stirring uniformly to obtain a component A mixture; (3) Add component B to the mixture of component A and stir to mix evenly; (4) The raw materials stirred in step (3) are quickly poured into a mold for free foaming to form a foam crude product, and the crude product is matured to obtain a fully water-foamed silicone polyurethane foam material.

8. The method for preparing the fully water-foamed organosilicon polyurethane foam material according to claim 7, characterized in that: The stirring is performed using a mechanical stirring device. The stirring speed in step (2) is ≥600 r / min, and the stirring time is 60 to 180 s; the stirring speed in step (3) is ≥1000 r / min, and the stirring time is 10 to 15 s.

9. The method for preparing the fully water-foamed organosilicon polyurethane foam material according to claim 7, characterized in that: In the step (4), the aging temperature is 70° C. and the aging time is 30-60 min.

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