A reactive polyether silane and alkali metal silicate coating stabilized thereby

Abstract

This application relates to the fields of polymer synthesis and coating technology, specifically providing a reactive polyether silane and its stabilized alkali metal silicate coating; the reactive polyether silane is prepared by an addition reaction of an unsaturated silane and a polyether amine; the structure of the polyether amine is: R'-[OCH2-CHR]. x -[OCH2-CH(CH3)] y The coating contains -NH2, with an x / y ratio of (1-55):(1-36), an HLB value of 0.5-20 for the polyetheramine, and a weight-average molecular weight of 500-6000; the mass ratio of unsaturated silane to polyetheramine is 100:(2-70); the coating composition includes 10-50% by mass of reactive polyether silane-stabilized alkali metal silicates. This application demonstrates that a small amount of polyether silane can effectively control the thermal stability of alkali metal silicate coatings, solving the problem of performance degradation after thermal storage, and possesses significant application value.

Description

Technical Field

[0001] This invention relates to the fields of polymer synthesis technology and coating technology, C08G65 / 26, and particularly to a reactive polyether silane and the alkali metal silicate coating stabilized therein. Background Technology

[0002] Alkali metal silicate coatings, a representative type of inorganic coatings, are characterized by their environmental friendliness, Class A non-flammability, excellent durability, wear resistance, and hardness. However, systems with silicates as the main film-forming agents are difficult to balance in terms of stability and reactivity because alkali metal silicates tend to spontaneously aggregate or react with polyvalent metal ions such as Mg. 2+ Ca 2+ Cu 2+ Zn 2+ Fe 3+ Al 3 + When alkali metal silicate coatings undergo almost irreversible ionic reactions, they generate insoluble silicates, leading to thickening and even gelation. This often results in problems such as gelation or poor washability, limiting the application range of alkali metal silicate coatings. Therefore, the key to solving the problems of silicate coatings is to maintain their stable state without reducing their reactivity.

[0003] Chinese patent CN112876888B discloses an inorganic liquid coating and its preparation method. This invention utilizes modified potassium silicate, modified silica sol, and a quaternary ammonium salt stabilizer, and selects free Ca2+. 2+ Using heavy calcium carbonate with very low ion content as a filler, a tough inorganic liquid coating with a wash resistance of ≥10,000 cycles was obtained. However, this method requires optimization and restriction of most raw materials, has stringent requirements, and the overall process is time-consuming, costly, and has poor applicability of the coating system. Chinese patent CN115895309A provides a flame-retardant inorganic composite resin, its preparation method, and its application in inorganic coatings. This invention significantly improves the stability of silica sol and potassium silicate by adjusting the ratio of silica sol and potassium silicate and adding an organosilane modifier. Simultaneously, the addition of methyl potassium silicate yields a flame-retardant composite inorganic resin with excellent stability suitable for inorganic coatings. However, the wash resistance of this inorganic coating is only 10,000 cycles, leaving significant room for improvement. Furthermore, none of the above patents address the fact that the wash resistance of coatings after heat storage often decreases due to the accelerated gelation reaction of silicates at high temperatures. However, the stability of wash resistance after heat storage is crucial for the long-term performance of the coating. Summary of the Invention

[0004] To address the aforementioned technical problems, the present invention first provides a reactive polyether silane, which is prepared by an addition reaction of an unsaturated silane and a polyether amine.

[0005] Furthermore, the unsaturated silane is a silane with unsaturated bonds, including but not limited to at least one of alkenyl, alkynyl, amide, and epoxy groups.

[0006] Preferably, the unsaturated bond is an epoxy group, and the unsaturated silane is an epoxysilane.

[0007] Furthermore, the unsaturated silane includes, but is not limited to, at least one of glycidoxypropyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethanedimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and 3-glycidoxypropyltriethoxysilane; optionally, Shin-Etsu Chemical KMB-303, KMB-402, KMB-403, KME-402, KME-403, etc.

[0008] Preferably, the epoxy silane comprises 3-glycidyl etheroxypropyltrimethoxysilane and / or 2-(3,4-epoxycyclohexyl)ethanedimethyltrimethoxysilane.

[0009] Furthermore, the structure of the polyetheramine is: R'-[OCH2-CHR] x -[OCH2-CH(CH3)] y -NH2, wherein R and R' are independently selected from any one of -H, alkyl, alkenyl, alkynyl, cycloalkyl, and heterocyclic groups.

[0010] Furthermore, R and R' are independently selected from any one of -H, C1-C30 alkyl, C2-C30 alkenyl, C2-C30 alkynyl, C3-C30 cycloalkyl, and C3-C30 heterocyclic groups.

[0011] Furthermore, R and R' are independently selected from any one of -H, C1-C20 alkyl, C2-C20 alkenyl, C2-C30 alkynyl, C3-C18 cycloalkyl, and C3-C20 heterocyclic groups.

[0012] Further, the x / y ratio is (1-55):(1-36), and the optional polyetheramines include, but are not limited to, those specified in the original text. B and At least one of the L series.

[0013] Preferably, the x / y ratio is (19-41):(3-10), and alternatively, it can be 19:3, 41:4, 33:10, 20:8, etc.

[0014] Furthermore, the HLB value of the polyetheramine is 0.5-20, preferably 13-19.

[0015] Furthermore, the polyetheramine has a weight-average molecular weight of 500-6000, preferably 600-5000.

[0016] More preferably, the polyetheramine has a weight-average molecular weight of 1000-3000, such as 1000, 1500, 2000, 2500, 3000, etc.

[0017] This application utilizes the addition reaction of polyetheramine and ring-opening epoxy silane to prepare polyether silane. This polyether silane relies on the appropriate molecular chain length and polar groups of the polyetheramine and epoxy silane to end-cap and molecularly encapsulate alkali metal silicates, preventing their spontaneous aggregation and cross-linking within the system. The weight-average molecular weight of the polyetheramine, the x / y ratio in its structure, and the HLB value have a significant impact on the stabilizing effect of the polyether silane. This is likely because the weight-average molecular weight of the polyetheramine dominates the molecular chain length of the polyether silane, and a suitable molecular chain length allows it to achieve a balance between stability and wettability in coatings. Secondly, the x / y ratio and HLB value directly affect the hydrophilicity and lipophilicity of the polyether silane, thus influencing its solubility in coating systems and its presence on alkali metal silicate surfaces. Both of these factors lead to differences in the stabilizing and wash-resistant enhancement effects of the final prepared polyether silane on silicate coatings.

[0018] In a preferred embodiment, the polyetheramine is selected from... L-100, L-207, L-200 At least one of L-300.

[0019] Furthermore, the mass ratio of the unsaturated silane to the polyetheramine is 100:(2-70); when the amount of polyetheramine is too large, due to the intermolecular forces between amino groups, hydroxyl groups or alkali metal silicates, the polyether silane wrapped by the outer layer of alkali metal silicates will generate greater interaction, destroying its encapsulation of silicates, resulting in a decrease in the storage stability of the coating.

[0020] Preferably, the mass ratio of the unsaturated silane to the polyetheramine is 100:(5-60).

[0021] In a preferred embodiment, the mass ratio of the unsaturated silane to the polyetheramine is 100:(10-50); alternatively, it can be 100:10, 100:15, 100:20, 100:25, 100:30, 100:35, 100:40, 100:45, 100:50, etc.

[0022] Furthermore, the preparation method of the reactive polyether silane includes the following steps: mixing unsaturated silane and polyether amine and reacting at 45-100℃ for 1-10 hours.

[0023] Furthermore, in the preparation method of the reactive polyether silane, the reaction temperature is 50-80℃ and the reaction time is 3-5h.

[0024] Secondly, this application provides the reactive polyether silane-stabilized alkali metal silicate coating, wherein the coating comprises reactive polyether silane-stabilized alkali metal silicates.

[0025] Furthermore, the alkali metal silicate includes, but is not limited to, at least one of lithium silicate, sodium silicate, and potassium silicate.

[0026] Furthermore, the modulus of the alkali metal silicate is 1-10, preferably 1-5.

[0027] Furthermore, the method for preparing the reactive polyether silane-stabilized alkali metal silicate is as follows: the reactive polyether silane and the alkali metal silicate are mixed and allowed to stand, wherein the amount of the reactive polyether silane is 0.5-10% of the mass of the alkali metal silicate. The polyether silane of this application contains end-group reactive nodes—unit amines. This amino group can participate in the long cross-linked structure of the alkali metal silicate, preventing its tendency for unlimited cross-linking during storage. However, when the amount of polyether silane is too large, its end-capping effect on the cross-linked structure of the alkali metal silicate is too strong, which will destroy the density and strength of the original coating network film structure, leading to a decrease in the washability of the coating. Therefore, it is necessary to strictly control the amount of polyether silane within the specified range.

[0028] Furthermore, the amount of the reactive polyether silane used is 1-8% of the mass of the alkali metal silicate, preferably 2-5%.

[0029] Further, based on the total mass of the coating, the coating comprises 10-50% reactive polyether silane-stabilized alkali metal silicate, preferably 20-40% reactive polyether silane-stabilized alkali metal silicate, more preferably 25-35% reactive polyether silane-stabilized alkali metal silicate.

[0030] Furthermore, based on the total mass of the coating, the coating also includes 4-30% emulsion, the emulsion including but not limited to at least one of pure acrylic emulsion, styrene-acrylic emulsion, fluorocarbon emulsion, silicone-acrylic emulsion, acrylic emulsion, epoxy resin emulsion, and polyurethane emulsion.

[0031] Preferably, the emulsion is a styrene-acrylic emulsion.

[0032] Furthermore, the coating also includes at least one of fillers, additives, and water.

[0033] Preferably, the coating further comprises 20-55% filler, 0.5-5% additives, and the balance water, based on the total mass of the coating.

[0034] Furthermore, the filler includes, but is not limited to, at least one of calcium carbonate, mica powder, quartz powder, and titanium dioxide.

[0035] Furthermore, the additives include, but are not limited to, at least one of stabilizers, wetting and dispersing agents, thickeners, defoamers, leveling agents, emulsifiers, anti-skinning agents, anti-settling agents, and anti-sagging agents.

[0036] Furthermore, the additives include thickeners, wetting and dispersing agents, and defoamers.

[0037] Furthermore, the coating comprises 0.3-2% thickener, 0.3-1.0% wetting and dispersing agent, and 0.2-0.5% defoamer.

[0038] Furthermore, the thickener includes, but is not limited to, at least one of reducing gum, hydroxyethyl cellulose, hydrophobically modified hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxyethylpropyl cellulose, hydroxypropyl methyl cellulose, and nonionic associative polyurethane.

[0039] Preferably, the thickener comprises hydrophobically modified hydroxyethyl cellulose and nonionic associative polyurethane, with a mass ratio of (0.5-1.0):(0.3-0.5).

[0040] Furthermore, the wetting and dispersing agent includes, but is not limited to, at least one of sodium oleate, carboxylates, sulfates, sulfonates, polyacrylates, alkyl quaternary ammonium salts, quaternary ammonium salts, aminopropylamine dioleate, octadeceneamine acetate, polyaminoamide phosphates, adducts of fatty acid ethylene oxide, polyethylene glycol, polyethyleneimine derivatives, polyphosphates, and oleylaminooleate.

[0041] Preferably, the wetting and dispersing agent comprises a polyacrylate salt.

[0042] Furthermore, the defoamer includes, but is not limited to, at least one of mineral oil, polyether, and higher alcohols.

[0043] Furthermore, the defoamer includes mineral oil.

[0044] Furthermore, the reactive polyether silane-stabilized alkali metal silicate coating is used in interior and exterior walls, industrial flooring, and other fields.

[0045] Furthermore, the reactive polyether silane-stabilized alkali metal silicate coating is applied by at least one of brushing, roller coating, scraping, spraying, and curtain coating.

[0046] Furthermore, the preparation method of the reactive polyether silane-stabilized alkali metal silicate coating is as follows: simply mix the raw materials evenly.

[0047] Preferably, the preparation method of the reactive polyether silane-stabilized alkali metal silicate coating is as follows:

[0048] S1. Mix water and additives.

[0049] S2. Add the filler to S1 and grind;

[0050] S3. Add the emulsion to S2 and stir;

[0051] S4. Add reactive polyether silane-stabilized alkali metal silicate to S3 and stir until well mixed.

[0052] Furthermore, in S2, the grinding speed is 1000-3500 rpm and the grinding time is 5-40 min.

[0053] Furthermore, in S3 and S4, the stirring speed is ≤1500 rpm, preferably ≤1000 rpm, and the mixing time is 3-30 min.

[0054] Beneficial effects

[0055] 1. This application uses a small amount of polyether silane, which effectively solves the problem of balancing high stability and high scrub resistance in alkali metal silicate coatings prepared by conventional modification methods. Its stabilization method for alkali metal silicates (steric hindrance and intermolecular forces) is simple and effective, which greatly reduces the negative impact of poor scrub resistance caused by excessive end-capping of silicates. It can also effectively control the thermal stability of alkali metal silicate coatings and solve the problem of performance degradation of alkali metal silicates after thermal storage, thus having important application value.

[0056] 2. This application optimizes the type, polarity, molecular weight, molecular structure, and relative amount of polyetheramine as a raw material for reactive polyether silanes, effectively improving the enhancing effect of the prepared polyether silanes on the stability and scrub resistance of silicate coatings.

[0057] 3. This application strictly controls the mass ratio of polyetheramine to epoxy silane and the amount of polyether silane added to alkali metal silicates in order to regulate the degree of crosslinking and end-capping of alkali metal silicates by polyether silane, and avoid the problem of reduced scrub resistance.

[0058] 4. The reactive polyether silane-stabilized alkali metal silicate coating of this application has excellent properties and can be used in interior and exterior walls, industrial floors and other fields, and can be used for coating on concrete surfaces. Detailed Implementation

[0059] Example

[0060] Examples 1-5

[0061] Examples 1-5 each provide a reactive polyether silane, and the raw materials for preparing the reactive polyether silane are shown in Table 1;

[0062] The method for preparing the reactive polyether silane is as follows: polyether amine and epoxy silane are added to the reactor in sequence, stirred evenly at a speed of 300 r / min, and then reacted at 80℃ for 5 h to finally obtain the reactive polyether silane product.

[0063] Table 1

[0064]

[0065] Examples 6-10

[0066] Examples 6-10 provide a reactive polyether silane-stabilized alkali metal silicate coating, the specific components of which are shown in Table 2.

[0067] The method for preparing the reactive polyether silane-stabilized alkali metal silicate is as follows: 100 parts by mass of 40% alkali metal silicate (potassium silicate or lithium silicate, both with a modulus of 3.5) are thoroughly mixed with 1 part of the polyether silane prepared in Examples 1-5, and then allowed to stand at room temperature for 2 hours. The amounts of alkali metal silicate and polyether silane are shown in Table 2.

[0068] The preparation method of the coating is as follows:

[0069] S1. Mix half the mass of water and additives (thickener, wetting and dispersing agent and defoamer) to form a gel-like substance. Stir at 300 rpm for 10 minutes.

[0070] S2. Add filler (heavy calcium carbonate) to the gel-like substance and grind it at 2000 rpm for 20 min;

[0071] S3. Add styrene-acrylic emulsion to S2 and mix at 800 rpm for 10 min.

[0072] S4. Add the reactive polyether silane-stabilized alkali metal silicate and the remaining water in sequence, mix at 800 rpm for 10 min to obtain the coating.

[0073] Table 2

[0074]

[0075]

[0076] Comparative Example 1

[0077] It is basically the same as Example 6, except that the alkali metal silicate is not modified in any way.

[0078] Comparative Example 2

[0079] It is basically the same as Example 6, except that the polyether silane is replaced with epoxy silane (Shin-Etsu KMB-403).

[0080] Comparative Example 3

[0081] This is essentially the same as Example 6, except that the polyether silane is replaced with a quaternary ammonium salt stabilizer (Clariant Dispersogen SPS).

[0082] Performance testing methods:

[0083] The coatings of Examples 6-10 and Comparative Examples 1-3 were tested according to the GB / T9756-2018 standard "Synthetic Resin Emulsion Interior Wall Coatings", and the results are shown in Table 3.

[0084] Performance test results:

[0085] Table 3

[0086]

[0087]

[0088] In summary, the silicate used in Comparative Example 1, without any treatment, exhibited a wash resistance of only 7500 cycles and gelled after 30 days of heat storage at 55°C, indicating an unstable coating system. In contrast, the alkali metal silicate coatings in Examples 6-10, treated with a small amount of polyether silane, all achieved a wash resistance of 21000 cycles. After 30 days of heat storage at 55°C, the viscosity increase was only a maximum of 8 KU, with almost no decrease in wash resistance, still exceeding 20000 cycles. Compared to Comparative Examples 2 and 3, Comparative Example 2 showed a viscosity increase of 35 KU after 30 days of heat storage at 55°C, significantly greater than the 7 KU increase in Example 1, reducing its wash resistance from 8500 cycles to 4000 cycles. Comparative Example 3, after 30 days of heat storage at 55°C, exceeded its viscosity range, and its wash resistance decreased to 5500 cycles, further decreasing to 2000 cycles after heat storage. It can be seen that the polyether silanes of Examples 1-5 can play a dual role in stabilizing and enhancing alkali metal silicates and their coating systems.

Claims

1. An alkali metal silicate coating, characterized in that, The coating comprises a reactive polyether silane-stabilized alkali metal silicate, which is prepared by mixing reactive polyether silane and alkali metal silicate and allowing the mixture to stand. The amount of reactive polyether silane used is 0.5-10% of the mass of the alkali metal silicate. The reactive polyether silane is prepared by an addition reaction of unsaturated silane and polyether amine; The unsaturated silane is a silane with unsaturated bonds, and the unsaturated bonds include at least one of alkenyl, alkynyl, amide, and epoxy groups; R'-[OCH2-CHR] x -[OCH2-CH(CH3)] y -NH2, wherein R and R' are independently selected from any one of -H, alkyl, alkenyl, alkynyl, cycloalkyl, heterocyclyl; x / y is (1-55): (1-36); The polyetheramine has an HLB value of 0.5-20; the polyetheramine has a weight-average molecular weight of 500-6000. The mass ratio of the unsaturated silane to the polyetheramine is 100:(2-70).

2. The coating according to claim 1, characterized in that, The mass ratio of the unsaturated silane to the polyetheramine is 100:(5-60).

3. The coating according to claim 1, characterized in that, The HLB value of the polyetheramine is 13-19.

4. The coating according to claim 1, characterized in that, The weight-average molecular weight of the polyetheramine is 600-5000.

5. The coating according to claim 1, characterized in that, The coating comprises 10-50% reactive polyether silane-stabilized alkali metal silicates by weight of total coating mass.

6. The coating according to any one of claims 1-5, characterized in that, The coating, by total mass, also includes 4-30% emulsion, wherein the emulsion includes at least one of pure acrylic emulsion, styrene-acrylic emulsion, fluorocarbon emulsion, silicone-acrylic emulsion, acrylic emulsion, epoxy resin emulsion, and polyurethane emulsion.

7. The coating according to claim 6, characterized in that, The emulsion includes styrene-acrylic emulsion.

8. The coating according to claim 6, characterized in that, The coating, by total mass, also includes 20-55% filler, 0.5-5% additives, and the balance water.

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