An anti-cracking base surface renovation composite primer and its preparation process

Abstract

The present invention relates to the technical field of architectural coating research and development, and discloses an anti-cracking base surface renovation composite primer and its preparation process, including: preparing an adhesion promoter containing a methoxy functional group, and the adhesion promoter containing a methoxy functional group is one of adhesion promoter I, adhesion promoter II, and adhesion promoter III; using an organosilicon-modified polyester resin emulsion, a silicone-acrylic emulsion, and an elastic emulsion as film-forming resin emulsions, adding an adhesion promoter containing a methoxy functional group to prepare an anti-cracking base surface renovation composite primer. The composite primer has excellent anti-cracking performance and bonding strength performance, and can meet the technical standards of type R flexible exterior wall putty for buildings in JG / T 157-2009 "Exterior Wall Putty for Buildings".

Description

Technical Field

[0001] The present invention relates to the technical field of architectural coating research and development, and specifically to an anti-cracking base surface renovation composite primer and its preparation process. Background Art

[0002] Base surface renovation refers to the process of reprocessing and repairing the basic surface of a building or ground to improve its appearance, performance, or extend its service life. Among them, the composite primer layer is a relatively key layer of materials in the base surface renovation coating system, mainly providing functions such as basic surface treatment and leveling, adhesion to the substrate, product thickness, shaping, anti-cracking, waterproofing, and coloring.

[0003] The primer is a liquid substance applied to the adherend substrate before construction. After curing, it forms a firm coating film that strongly adheres to the substrate surface. This adhesion is not only physical adsorption but also the action of chemical bonds, that is, chemical adsorption. The primer layer is the transition layer between the base surface and the adherend substrate. Because its adhesion to the base surface glue and the adherend substrate is better than that between the base surface glue and the substrate, the adhesion performance between the base surface glue and the substrate is strengthened.

[0004] Building walls are exposed to the atmosphere for a long time and are affected by natural factors such as temperature changes due to thermal expansion and contraction and the shrinkage of concrete hardening. Small turtle-shaped cracks are likely to occur in the wall base layer and will expand as the service time extends. In the light case, it will affect the surface decoration effect of the building, and in the severe case, it will even cause wall seepage, seriously affecting the decoration effect and service life of the exterior wall. Therefore, in order to meet the needs of the wall base substrate for cracking and stretching and covering fine cracks in the base layer, it has certain practical significance to develop an anti-cracking base surface renovation composite primer.

[0005] At present, the main ways to improve the anti-cracking ability of coatings are as follows: Selecting a Si-O bond molecular chain with a relatively large bond energy as the main film-forming resin emulsion, overcoming the shortcoming of the film-forming resin emulsion with a common C-C bond molecular chain having a short ultraviolet irradiation resistance time (such as using an organosilicon-based film-forming resin emulsion, etc.); adjusting the microscopic network structure of the film-forming resin molecular chain to make the resin have better elasticity and avoid coating cracking caused by temperature gradient impact (such as adding an elastic emulsion, etc.); adding an adhesion promoter with high compatibility with the film-forming resin emulsion to make the coating have excellent adhesion to the substrate and avoid the cracking phenomenon of the coating caused by substrate expansion and contraction.

[0006] The present invention cites the chemical structure and preparation method of octaaminopropyl POSS (OA-POSS) disclosed in the article "Research on DOPO Derivatives / Octaaminopropyl POSS Flame Retardant Wood-Plastic Composites" published by Zhang Ling et al. in the Journal of Southwest Forestry University, Vol. 43, No. 3, pp. 136-144, in May 2023. Summary of the Invention

[0007] The present invention provides a preparation process for an anti-cracking base surface renovation composite primer. On the one hand, the technical goal of improving the anti-cracking performance of the coating is achieved by adding an elastic emulsion raw material to the formula. On the other hand, a newly developed adhesion promoter is used to improve the bonding strength between the primer and the substrate, ensuring that the composite primer forms a firm adhesion on the surface of the substrate. The base surface renovation composite primer prepared thereby can meet the technical standards of Type R flexible exterior wall putty in JG / T 157-2009 "Exterior Wall Putty for Buildings".

[0008] A preparation process for an anti-cracking base surface renovation composite primer includes the following steps:

[0009] Step 1: Prepare an adhesion promoter containing a methoxy functional group, and the adhesion promoter containing a methoxy functional group is one of adhesion promoter I, adhesion promoter II, and adhesion promoter III;

[0010] Step 2: Prepare an anti-cracking base surface renovation composite primer, and the formula of the anti-cracking base surface renovation composite primer is: 15-20 parts by weight of water, 5-15 parts by weight of an organosilicon-modified polyester resin emulsion, 5-15 parts by weight of a silicon-acrylic emulsion, 5-15 parts by weight of an elastic emulsion, 5-10 parts by weight of cellulose, 0.1-1 part by weight of an antifreeze, 0.5-2 parts by weight of a film-forming aid, 0.1-1 part by weight of a pH regulator, 1-3 parts by weight of a dispersant, 1-3 parts by weight of an antifoaming agent, 0.1-1 part by weight of a wetting agent, 15-30 parts by weight of a filler, 1-5 parts by weight of a protective colloid, 1-3 parts by weight of a protective colloid auxiliary, 1-3 parts by weight of a thickener, 1-3 parts by weight of a preservative, 1-3 parts by weight of an adhesion promoter, and 1-3 parts by weight of a crosslinking agent.

[0011] Preferably, the preparation method of the adhesion promoter I is: an addition reaction occurs between the alkenyl functional group of allyltrimethoxysilane and the Si-H functional group of 1-n-butyl-1,1,3,3-tetramethyldisiloxane to generate the adhesion promoter I.

[0012] Preferably, the preparation method of the adhesion promoter II is: under the catalytic action of a phase transfer catalyst, a nucleophilic substitution reaction occurs between the hydroxyl functional group of 1,3-bis(3-hydroxypropyl)-1,1,3,3-tetramethyldisiloxane and the chloro functional group of 3-chloropropyltrimethoxysilane to generate the adhesion promoter II.

[0013] Preferably, the phase transfer catalyst is one of benzyltriethylammonium chloride, tetrabutylammonium hydrogensulfate, and tetrabutylammonium bromide.

[0014] Preferably, the method for preparing the adhesion promoter III is as follows: the bromo-functional group of 3-chloropropyltrimethoxysilane and the amino-functional group of octaaminopropyl POSS undergo a nucleophilic substitution reaction to generate the adhesion promoter III.

[0015] Preferably, the cellulose is one or a combination of two of hydroxyethyl cellulose and hydroxyethyl methyl cellulose;

[0016] Preferably, the antifreeze is one or a combination of several of propylene glycol, ethylene glycol, polyethylene glycol, and polypropylene glycol;

[0017] Preferably, the film-forming aid is alcohol ester twelve;

[0018] Preferably, the pH regulator is one or a combination of two of 2-amino-2-methyl-1-propanol and N,N-dimethylethanolamine;

[0019] Preferably, the dispersant is an ammonium polyacrylate dispersant;

[0020] Preferably, the defoamer is a silicone defoamer;

[0021] Preferably, the wetting agent is octylphenol polyoxyethylene ether;

[0022] Preferably, the filler is one or a combination of several of kaolin, quartz sand, talc powder, and calcium carbonate;

[0023] Preferably, the protective colloid is one or a combination of two of magnesium aluminum silicate and magnesium lithium silicate;

[0024] Preferably, the protective colloid aid is one or a combination of two of bentonite and xanthan gum;

[0025] Preferably, the thickener is polyacrylate;

[0026] Preferably, the preservative is one or a combination of two of 5-chloro-2-methyl-4-isothiazolin-3-one and 2-methyl-4-isothiazolin-3-one;

[0027] Preferably, the crosslinking agent is one or a combination of two of polycarbodiimide and N,N-methylenebisacrylamide.

[0028] An anti-cracking base surface renovation composite primer, comprising the following raw materials in parts by weight:

[0029] 15 - 20 parts of water, 5 - 15 parts of organosilicon - modified polyester resin emulsion, 5 - 15 parts of silicon - acrylic emulsion, 5 - 15 parts of elastic emulsion, 3 - 6 parts of hydroxyethyl cellulose, 2 - 4 parts of hydroxyethyl methyl cellulose, 0.1 - 1 part of propylene glycol, 0.5 - 2 parts of alcohol ester 12, 0.1 - 1 part of 2 - amino - 2 - methyl - 1 - propanol, 1 - 3 parts of ammonium polyacrylate dispersant, 1 - 3 parts of organosilicon defoamer, 0.1 - 1 part of octylphenol polyoxyethylene ether, 5 - 12 parts of calcium carbonate, 10 - 18 parts of quartz sand, 1 - 5 parts of magnesium aluminum silicate, 1 - 3 parts of bentonite, 1 - 3 parts of polyacrylate, 1 - 3 parts of 2 - methyl - 4 - isothiazolin - 3 - one, 1 - 3 parts of adhesion promoter, 1 - 3 parts of N,N - methylenebisacrylamide.

[0030] Beneficial effects:

[0031] First, based on the molecular design mechanism, the present invention synthesizes three adhesion promoters containing methoxy functional groups; then, using organosilicon - modified polyester resin emulsion, silicon - acrylic emulsion and elastic emulsion as film - forming resin emulsions, and adding an adhesion promoter containing methoxy functional groups, an anti - cracking base surface renovation composite primer is prepared.

[0032] It can be seen from the experimental results that the anti - cracking performance of the base surface renovation composite primer prepared by the present invention is excellent and can meet the technical standards of type R flexible exterior wall putty for buildings in JG / T 157 - 2009 "Exterior Wall Putty for Buildings". Specific implementation mode

[0033] Example 1:

[0034] Prepare adhesion promoter Ⅰ: Through the addition reaction of the alkenyl functional group of allyltrimethoxysilane and the Si - H functional group of 1 - n - butyl - 1,1,3,3 - tetramethyldisiloxane, adhesion promoter Ⅰ is generated, and its chemical structural formula is:

[0035]

[0036] The specific experimental steps for preparing adhesion promoter Ⅰ are as follows: Under the protection of nitrogen, 1.9 g of 1 - n - butyl - 1,1,3,3 - tetramethyldisiloxane and 20 mL of anhydrous tetrahydrofuran are added to a three - necked flask, stirred at room temperature until completely dissolved, then 10 mL of an anhydrous tetrahydrofuran solution containing 1.6 g of allyltrimethoxysilane and 5 drops of Karstedt catalyst are successively added dropwise to the three - necked flask, heated to 70 °C and stirred under reflux for 10 h, cooled to room temperature, the solvent is removed by rotary evaporation, and vacuum dried to obtain adhesion promoter Ⅰ;

[0037] The nuclear magnetic resonance hydrogen spectrum characterization of adhesion promoter Ⅰ is: 11H NMR (CDCl3, 400 MHz) δ: 0.08 (s, 6H), 0.13 (s, 6H), 0.57 - 0.61 (t, 2H), 0.68 - 0.74 (m, 4H), 0.93 - 0.97 (t, 3H), 1.18 - 1.29 (m, 4H), 1.41 - 1.48 (m, 2H), 3.57 (s, 9H).

[0038] Example 2:

[0039] Preparation of adhesion promoter II: Under the catalysis of a phase transfer catalyst, the hydroxyl functional groups of 1,3 - bis(3 - hydroxypropyl)-1,1,3,3 - tetramethyldisiloxane react with the chlorine functional groups of 3 - chloropropyltrimethoxysilane through nucleophilic substitution reaction to generate adhesion promoter II, and its chemical structural formula is

[0040]

[0041] Among them, the phase transfer catalyst is one of benzyltriethylammonium chloride, tetrabutylammonium hydrogensulfate, and tetrabutylammonium bromide; in this experimental example, tetrabutylammonium bromide is selected for use;

[0042] The specific experimental steps for preparing adhesion promoter II are as follows: Add 2.5 g of 1,3 - bis(3 - hydroxypropyl)-1,1,3,3 - tetramethyldisiloxane, 2 mL of 30 wt% sodium hydroxide aqueous solution, and 50 mL of N,N - dimethylformamide into a three - necked flask, stir at room temperature until completely dissolved, and then sequentially add 1.9 mL of 3 - chloropropyltrimethoxysilane and 2 mL of deionized aqueous solution containing 1.1 g of tetrabutylammonium bromide to the three - necked flask, heat up to 70 °C and stir for reaction for 10 h, cool to room temperature, rotate - evaporate to remove the solvent, and dry under vacuum to obtain adhesion promoter II;

[0043] 1H NMR characterization of adhesion promoter II is as follows: 1 1H NMR (CDCl3, 400 MHz) δ: 0.06 (s, 6H), 0.11 (s, 6H), 0.59 - 0.63 (t, 4H), 0.74 - 0.77 (t, 4H), 1.51 - 1.58 (m, 4H), 1.69 - 1.76 (m, 4H), 3.25 - 3.29 (t, 4H), 3.39 - 3.43 (t, 4H), 3.57 (s, 18H).

[0044] Example 3:

[0045] Preparation of adhesion promoter III: Through the nucleophilic substitution reaction of the bromine functional groups of 3 - chloropropyltrimethoxysilane and the amino functional groups of octaaminopropyl POSS (OA - POSS), adhesion promoter III is generated, and its chemical structural formula is:

[0046]

[0047] The specific experimental steps for preparing adhesion promoter Ⅲ are as follows: Add 4.4 g of octaaminopropyl POSS, 1.5 g of sodium bicarbonate, and 50 mL of N,N-dimethylformamide into a three-necked flask. Under the protection of nitrogen and mechanical stirring, dissolve at room temperature for 1 h. Then, add 4.2 mL of 3-chloropropyltrimethoxysilane dropwise into the three-necked flask, heat up to 60 °C, stir and react for 12 h, cool to room temperature, remove the solvent by rotary evaporation, and dry under vacuum to obtain adhesion promoter Ⅲ;

[0048] The 1H NMR characterization of adhesion promoter Ⅲ is as follows: 1 H NMR(CDCl3, 400 MHz) δ: 0.56 - 0.70 (m, 32H), 1.46 - 1.62 (m, 32H), 2.60 - 2.74 (m, 32H), 3.57 (s, 72H).

[0049] Example 4:

[0050] To prepare an anti-cracking base surface renovation composite primer, the following steps are included:

[0051] Step 1, prepare a pre-solution: According to the formula in Table 1, add water, organosilicon-modified polyester resin emulsion, silicon-acrylic emulsion, elastic emulsion, hydroxyethyl cellulose, hydroxyethyl methyl cellulose, propylene glycol, alcohol ester 12, 2-amino-2-methyl-1-propanol, ammonium polyacrylate dispersant, organosilicon defoamer, and octylphenol polyoxyethylene ether into a disperser and mix them. Stir at 800 r / min for 60 min to obtain the pre-solution;

[0052] Step 2, prepare the anti-cracking base surface renovation composite primer: According to the formula in Table 1, add calcium carbonate, quartz sand, magnesium aluminum silicate, bentonite, polyacrylate, 2-methyl-4-isothiazolin-3-one, and adhesion promoter into the pre-solution prepared in Step 1. Stir at 1000 r / min for 60 min, then add N,N-methylenebisacrylamide, and continue to stir at 1000 r / min for 60 min to obtain the anti-cracking base surface renovation composite primer;

[0053] Table 1 Raw material formula of the anti-cracking base surface renovation composite primer

[0054]

[0055]

[0056] Among them, when the adhesion promoter is adhesion promoter I, adhesion promoter II, and adhesion promoter III respectively, the crack-resistant base surface renovation composite primer I, crack-resistant base surface renovation composite primer II, and crack-resistant base surface renovation composite primer III are prepared in sequence.

[0057] Comparative Example 1:

[0058] Prepare composite primer a: Compared with the crack-resistant base surface renovation composite primer I, the only difference is that: silicone-acrylic emulsion is used to replace the elastic emulsion.

[0059] Comparative Example 2:

[0060] Prepare composite primer b: Compared with the crack-resistant base surface renovation composite primer I, the only differences are that: silicone-acrylic emulsion is used to replace the elastic emulsion and adhesion promoter I is not used.

[0061] Performance test:

[0062] The crack-resistant base surface renovation composite primer is coated by scraping. After curing at room temperature, a crack-resistant composite coating is formed for performance testing. The results are shown in Table 2.

[0063] Table 2 Performance test results of the crack-resistant base surface renovation composite primer

[0064]

[0065] Through comprehensive analysis of the above experimental results, the following conclusions can be drawn:

[0066] Conclusion 1: By adding elastic emulsion to the formula, the crack-resistant base surface renovation composite primer prepared in the present invention has excellent crack-resistant performance and can meet the technical standards of R-type flexible exterior wall putty in JG / T 157-2009 "Exterior Wall Putty for Buildings" (the maximum width of the base layer crack before the putty layer cracks > 0.3 mm, bond strength > 0.6 MPa);

[0067] Conclusion 2: Compared with the composite primer without adding adhesion promoter, the base surface renovation composite primer prepared in the present invention using the newly developed adhesion promoter has achieved a beneficial technical effect of significant improvement in bond strength performance;

[0068] Among them, adhesion promoter III has the best effect on improving the bond strength performance of the base surface renovation composite primer;

[0069] The mechanism for the above experimental results may be that: the silanol functional groups generated by the hydrolysis reaction of the siloxane groups in the adhesion promoter can undergo a condensation reaction with the hydroxyl functional groups on the substrate surface to form a stable siloxane bond structure, thereby enhancing the adhesion between the coating and the substrate and ensuring a firm attachment of the coating on the substrate surface.

Claims

1. A preparation process of an anti-cracking base surface renovation composite primer, characterized in that, It includes the following steps: Step 1: Prepare an adhesion promoter containing a methoxy functional group, and the adhesion promoter containing a methoxy functional group is one of adhesion promoter I, adhesion promoter II, and adhesion promoter III; The chemical structural formula of adhesion promoter I is: ； The chemical structural formula of adhesion promoter II is: ； The chemical structural formula of adhesion promoter III is: ； Step 2: Prepare an anti-cracking base surface renovation composite primer, and the formula of the anti-cracking base surface renovation composite primer is: 15-20 parts by weight of water, 5-15 parts by weight of organosilicon-modified polyester resin emulsion, 5-15 parts by weight of silicon-acrylic emulsion, 5-15 parts by weight of elastic emulsion, 5-10 parts by weight of cellulose, 0.1-1 part by weight of antifreeze, 0.5-2 parts by weight of film-forming aid, 0.1-1 part by weight of pH regulator, 1-3 parts by weight of dispersant, 1-3 parts by weight of defoamer, 0.1-1 part by weight of wetting agent, 15-30 parts by weight of filler, 1-5 parts by weight of protective colloid, 1-3 parts by weight of protective colloid auxiliary, 1-3 parts by weight of thickener, 1-3 parts by weight of preservative, 1-3 parts by weight of the adhesion promoter containing a methoxy functional group in the above step 1, and 1-3 parts by weight of crosslinking agent.

2. The preparation process of an anti-cracking base surface renovation composite primer according to claim 1, characterized in that, The preparation method of the adhesion promoter I is: an addition reaction occurs between the alkenyl functional group of allyltrimethoxysilane and the Si-H functional group of 1-n-butyl-1,1,3,3-tetramethyldisiloxane to generate adhesion promoter I.

3. The preparation process of an anti-cracking base surface renovation composite primer according to claim 1, characterized in that, The preparation method of the adhesion promoter II is: under the catalytic action of a phase transfer catalyst, a nucleophilic substitution reaction occurs between the hydroxyl functional group of 1,3-bis(3-hydroxypropyl)-1,1,3,3-tetramethyldisiloxane and the chlorine functional group of 3-chloropropyltrimethoxysilane to generate adhesion promoter II.

4. The preparation process of an anti-cracking base surface renovation composite primer according to claim 3, characterized in that, The phase transfer catalyst is one of benzyltriethylammonium chloride, tetrabutylammonium hydrogensulfate, and tetrabutylammonium bromide.

5. The preparation process of an anti-cracking base surface renovation composite primer according to any one of claims 1-4, characterized in that, The cellulose is one or a combination of two of hydroxyethyl cellulose and hydroxyethyl methyl cellulose; The antifreeze is one or a combination of several of propylene glycol, ethylene glycol, polyethylene glycol, and polypropylene glycol; The film-forming aid is alcohol ester twelve; The pH regulator is one or a combination of two of 2-amino-2-methyl-1-propanol and N,N-dimethylethanolamine; The dispersant is an ammonium polyacrylate salt dispersant; The defoamer is an organosilicon defoamer; The wetting agent is octylphenol polyoxyethylene ether; The filler is one or a combination of several of kaolin, quartz sand, talc powder, and calcium carbonate; The protective colloid is one or a combination of two of magnesium aluminum silicate and magnesium lithium silicate; The protective colloid auxiliary is one or a combination of two of bentonite and xanthan gum; The thickener is polyacrylate; The preservative is one or a combination of two of 5-chloro-2-methyl-4-isothiazolin-3-one and 2-methyl-4-isothiazolin-3-one; The crosslinking agent is one or a combination of two of polycarbodiimide and N,N-methylenebisacrylamide.

6. An anti-cracking base surface renovation composite primer prepared by the process according to any one of claims 1-4, characterized in that, The anti-cracking base surface renovation composite primer comprises raw materials in the following parts by weight: 15 - 20 parts of water, 5 - 15 parts of organosilicon-modified polyester resin emulsion, 5 - 15 parts of silicon-acrylic emulsion, 5 - 15 parts of elastic emulsion, 3 - 6 parts of hydroxyethyl cellulose, 2 - 4 parts of hydroxyethyl methyl cellulose, 0.1 - 1 part of propylene glycol, 0.5 - 2 parts of alcohol ester 12, 0.1 - 1 part of 2-amino-2-methyl-1-propanol, 1 - 3 parts of ammonium polyacrylate dispersant, 1 - 3 parts of organosilicon defoamer, 0.1 - 1 part of octylphenol polyoxyethylene ether, 5 - 12 parts of calcium carbonate, 10 - 18 parts of quartz sand, 1 - 5 parts of magnesium aluminum silicate, 1 - 3 parts of bentonite, 1 - 3 parts of polyacrylate, 1 - 3 parts of 2-methyl-4-isothiazolin-3-one, 1 - 3 parts of the adhesion promoter containing methoxy functional groups in the first step, 1 - 3 parts of N,N-methylenebisacrylamide.

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