A kind of vinato emulsion for exterior wall coating and preparation method thereof

Abstract

The present invention provides a vinato emulsion for exterior wall coating and a preparation method thereof. The vinato emulsion is obtained by polymerization reaction of a pre-emulsion and a still bottom liquid, wherein the pre-emulsion comprises the following monomer components in parts by weight: 18-22 parts of acrylic soft monomers, 20-30 parts of vinyl acetate, 8-12 parts of versatate vinyl carbonate, 1-3 parts of functional monomers, and 1-3 parts of organosilicon monomers, wherein the functional monomers are hydrophilic monomers; the pre-emulsion comprises an emulsifier 1, wherein the emulsifier 1 is composed of anionic emulsifiers and nonionic emulsifiers; the still bottom liquid comprises an emulsifier 2, wherein the emulsifier 2 is composed of reactive emulsifiers and nonionic emulsifiers. The vinato emulsion of the present invention has good compatibility with substrates, good adhesion, good paint stability, good fire resistance, water whitening resistance, good dilution stability, and good compatibility with alkaline substrates.

Description

Technical Field

[0001] The invention relates to the technical field of materials, and in particular to a vacce-velop emulsion for exterior wall coatings and a preparation method thereof. Background Art

[0002] Exterior wall coatings play a vital role in the maintenance of buildings and beautification of the environment. Exterior wall coatings are constantly developing towards water-based, highly decorative, highly weather-resistant, and environmentally friendly. In the prior art, the exterior wall coating materials commonly found on the market generally have poor paint stability, have the problem of water absorption and whitening, and have poor expansion coefficients, causing problems such as cracking and bulging of the paint surface. In addition, the existing coating materials have poor compatibility with the substrate, the fireproof effect is not obvious, and the adhesion is not ideal. Therefore, it is urgent to develop a coating material with good fire resistance, good water whitening resistance, good stability, and strong adhesion.

[0003] VAT emulsion is made of vinyl acetate modified by plasticization of tert-butyl vinyl carbonate and polymerized by self-crosslinking technology. Due to its good environmental protection and gloss, it is increasingly becoming one of the first film-forming substances for decorative coatings. Vinyl acetate has a low film-forming temperature, which can reduce the amount of film-forming aids added and reduce the production cost of coating companies. But at the same time, VAT emulsion still needs to be improved in terms of overall performance. When it is used in exterior wall coatings, it has problems such as water absorption and whitening, poor expansion coefficient, and poor adhesion to the substrate that need to be improved. Summary of the invention

[0004] In view of this, the purpose of the present invention is to solve the above problems and propose a vinanoic acid emulsion for exterior wall coatings and a preparation method thereof. The vinanoic acid emulsion of the present invention has good compatibility with substrates, good adhesion, good paint stability, good fire resistance, water whitening resistance, and good compatibility with alkaline substrates.

[0005] The technical solution of the present invention is as follows:

[0006] A vinato vacce emulsion for exterior wall coatings, obtained by polymerization of pre-emulsified liquid and kettle bottom liquid.

[0007] The pre-emulsion comprises the following monomer components in parts by weight: 18-22 parts of acrylic soft monomer, 20-30 parts of vinyl acetate, 8-12 parts of vinyl versatate, 1-3 parts of functional monomer, and 1-3 parts of organosilicon monomer, wherein the functional monomer is a hydrophilic monomer;

[0008] The pre-emulsion includes emulsifier 1, which is composed of anionic emulsifier and nonionic emulsifier; the kettle bottom liquid includes emulsifier 2, which is composed of reactive emulsifier and nonionic emulsifier.

[0009] In the monomer components of the present invention, organic silicon monomers and hydrophilic functional monomers are introduced on the basis of acrylic soft monomers, vinyl acetate and vinyl ester carbonate. The organic silicon monomers, vinyl acetate, vinyl ester carbonate and other components improve the compatibility of the emulsion with the substrate through coupling interaction, reduce the interfacial tension between the coating and the substrate, and improve the adhesion and stability of the coating; the hydrophilic functional monomers react with vinyl acetate, vinyl ester carbonate and other components to form a water-soluble or water-dispersible structure in the coating, thereby increasing the resistance of the coating to water, reducing the whitening phenomenon caused by water absorption of the coating, and improving the water-whitening resistance of the coating.

[0010] As a preferred technical solution of the present invention, the acrylic soft monomer is selected from butyl acrylate, isooctyl acrylate or a mixture of the two. The acrylic soft monomer polymer with a glass transition temperature of -20 to -70°C gives the emulsion good elasticity, softness and ductility after film formation.

[0011] As a preferred technical solution of the present invention, the functional monomer is selected from a mixture of hydrophilic monomers acrylic acid and acrylamide. Preferably, the weight ratio of acrylic acid to acrylamide is 1:1. The hydrophilic monomer helps to increase the resistance of the coating to water, reduce the whitening phenomenon caused by water absorption of the coating, and improve the water whitening resistance of the coating.

[0012] As a preferred technical solution of the present invention, the organosilicon monomer is selected from one or a combination of vinyl trimethoxysilane, γ-methacryloxypropyl trimethoxysilane, and γ-(2,3-epoxypropyloxy)propyl trimethoxysilane. For example, it can be selected from A171 silane coupling agent, A174 silane coupling agent, A187 silane coupling agent, etc. produced by Momentive. As a cross-linking agent, the organosilicon monomer increases the strength of the coating and improves the stability and durability of the finished paint by cross-linking reaction with other components in the vinanoic acid emulsion.

[0013] As a preferred technical solution of the present invention, in the emulsifier 1, the anionic emulsifier is selected from one or a combination of fatty alcohol polyoxyethylene ether succinic sulfonate, sodium dodecyl diphenyl oxide disulfonate, and sodium allyloxy hydroxypropyl sulfonate; further, the fatty alcohol polyoxyethylene ether succinic sulfonate is a sulfonate obtained by sulfonating fatty alcohol with polyoxyethylene (EO). For example, the AEROSOL A-102 emulsion emulsifier of Cytec can be used; the sodium dodecyl diphenyl oxide disulfonate can be DOWFAX 2A1 emulsifier of Dow Chemical.

[0014] The nonionic emulsifier is selected from fatty alcohol ethoxylate emulsifiers, for example, one or more of the emulsifiers of models LCN287, LCN407 and LCN118 produced by Clariant.

[0015] In the specific implementation process, in the emulsifier 1, the weight portion of the anionic emulsifier is 0.5-2 parts, and the weight portion of the nonionic emulsifier is 1-2 parts.

[0016] As a preferred technical solution of the present invention, in the emulsifier 2, the reactive emulsifier is selected from sodium allyloxyhydroxypropane sulfonate. Further, for example, Solvay model COPS-1 emulsifier can be used.

[0017] The nonionic emulsifier is selected from fatty alcohol ethoxylate emulsifiers, for example, one or more emulsifiers of the types LCN287, LCN407 and LCN118 produced by Clariant.

[0018] In the specific implementation process, in the emulsifier 2, the weight portion of the reactive emulsifier is 1-3 parts, and the weight portion of the non-ionic emulsifier is 1-3 parts.

[0019] The selection of the emulsifier of the present invention plays a key role in preparing an emulsion with suitable performance. The use of anionic emulsifiers and nonionic emulsifiers in the pre-emulsion to emulsify each monomer is conducive to the interaction of each monomer and improves the sufficiency of polymerization; the use of reactive emulsifiers and nonionic emulsifiers in the bottom liquid of the reactor, the introduction of reactive nonionic emulsifiers makes the emulsion more sufficient during the cross-linking reaction and improves the reaction stability. However, the use of a single emulsifier increases the risk of experimental failure, the emulsion is easy to demulsify, and the reaction stability becomes poor. The emulsion prepared by this combination of emulsifiers has high stability and good expansion coefficient, and the paint surface is not easy to crack or bulge during application.

[0020] As a preferred technical solution of the present invention, the pre-emulsion includes initiator 1, the kettle bottom liquid includes initiator 2, the initiator 1 and initiator 2 are selected from one of ammonium persulfate, potassium persulfate and sodium persulfate, and the amount of the initiator is the conventional amount used in the art.

[0021] A method for preparing a vac-vegetal emulsion for exterior wall coatings comprises the following steps:

[0022] Prepare the raw materials according to the recipe; this step can be prepared separately or carried out simultaneously during the preparation process;

[0023] Preparing pre-emulsion: Mix water, emulsifier 1, acrylic soft monomer, vinyl acetate, vinyl ester carbonate, functional monomer, silicone monomer and initiator 1, and stir evenly to obtain pre-emulsion;

[0024] Prepare the bottom liquid of the kettle: add water and emulsifier 2 into the reactor and stir evenly, heat up to the reaction temperature, then add initiator 2 and keep stirring;

[0025] 1-5% of the total mass of the pre-emulsion is added to the bottom liquid of the reactor. After the temperature in the reactor rises to the reaction temperature, the remaining pre-emulsion is added dropwise at a uniform speed. After the addition is completed, the pH value is adjusted to obtain an emulsion.

[0026] As a preferred technical solution of the present invention, the reaction temperature is 70-75° C., and the total time of the dropwise addition reaction in step (4) is controlled to be 3-5 hours.

[0027] In the preparation process of the present invention, each monomer is first fully mixed with emulsifier 1 and initiator 1 in a pre-emulsion, and then emulsifier 2 and initiator 2 are fully mixed in a kettle bottom liquid. When the appropriate reaction time (appropriate reaction temperature) is reached, a small portion of the pre-emulsion is first added to the kettle bottom liquid for reaction to generate a seed emulsion with an appropriate particle size. After the reaction is stable, the remaining pre-emulsion is uniformly added dropwise for a stable polymerization reaction to finally prepare an emulsion with appropriate performance.

[0028] Compared with the prior art, the technical solution provided by the present invention has the following significant beneficial effects:

[0029] On the basis of acrylic soft monomers, vinyl acetate and versatate vinyl ester, silicone monomers and hydrophilic functional monomers are introduced to improve the compatibility of the emulsion with the substrate, reduce the interfacial tension between the coating and the substrate, improve the adhesion and stability of the coating, increase the coating's resistance to water, reduce the whitening phenomenon caused by water absorption of the coating, and improve the coating's resistance to water whitening.

[0030] Through the selection and matching of emulsifiers, anionic emulsifiers and nonionic emulsifiers are used in the pre-emulsion to fully emulsify each monomer, and reactive emulsifiers and nonionic emulsifiers are used in the bottom liquid of the reactor, so that the emulsion is more fully cross-linked and the reaction stability is greatly improved. In the pre-emulsion, each monomer is first fully mixed with emulsifier 1 and initiator 1, and in the bottom liquid of the reactor, emulsifier 2 and initiator 2 are fully mixed. A small part of the pre-emulsion is added to the bottom liquid of the reactor to react to generate a seed emulsion with a suitable particle size. After the reaction is stable, the remaining pre-emulsion is uniformly added dropwise for a stable polymerization reaction, and finally an emulsion with excellent performance and good stability is prepared.

[0031] The emulsion obtained by the invention has excellent performance, good compatibility with substrates, good adhesion, good paint stability, good fire resistance, water whitening resistance, good dilution stability, good compatibility with alkaline substrates, and meets the use requirements of exterior wall coatings. DETAILED DESCRIPTION

[0032] In order to have a clearer understanding of the technical features, purposes and beneficial effects of the present invention, the technical solution of the present invention is now described in detail below, but it should not be understood as limiting the scope of the present invention. The experimental methods described in the following examples are conventional methods unless otherwise specified; the reagents and materials can be obtained from commercial sources unless otherwise specified.

[0033] Example 1

[0034] A method for preparing a vac-vegetal emulsion for exterior wall coatings, specifically comprising the following steps:

[0035] Prepare the raw materials according to the formula in Table 1;

[0036] Prepare the pre-emulsion: add water and emulsifier 1 into the monomer tank, stir evenly, then add acrylic soft monomer, vinyl acetate, versatate vinyl carbonate, functional monomer, silicone monomer and initiator 1, stir evenly to obtain the pre-emulsion.

[0037] Prepare the bottom liquid: add water and emulsifier 2 into the reactor and stir evenly, heat to about 73°C, then add initiator 2 and keep stirring;

[0038] Take about 5% of the total mass of the pre-emulsion in the monomer tank and add it into the reactor. After the temperature in the reactor rises to 73°C, start to add the remaining pre-emulsion at a uniform rate. The total dropping time is controlled within 4 hours. After the dropping is completed, adjust the pH value to 3 to complete the preparation of the emulsion.

[0039] Table 1

[0040]

[0041] Example 2

[0042] A method for preparing a vac-vegetal emulsion for exterior wall coatings, specifically comprising the following steps:

[0043] Prepare the raw materials according to the formula in Table 2;

[0044] Prepare the pre-emulsion: add water and emulsifier 1 into the monomer tank, stir evenly, then add acrylic soft monomer, vinyl acetate, versatate vinyl carbonate, functional monomer, silicone monomer and initiator 1, stir evenly to obtain the pre-emulsion.

[0045] Prepare the bottom liquid: add water and emulsifier 2 into the reactor and stir evenly, raise the temperature to 72°C, then add initiator 2 and keep stirring;

[0046] Take about 4% of the total mass of the pre-emulsion in the monomer tank and add it into the reactor. After the temperature in the reactor rises to 72°C, start to add the remaining pre-emulsion at a uniform rate. The total dropping time is controlled within 4 hours. After the dropping is completed, adjust the pH value to 3 to complete the preparation of the emulsion.

[0047] Table 2

[0048]

[0049]

[0050] Example 3

[0051] A method for preparing a vac-vegetal emulsion for exterior wall coatings, specifically comprising the following steps:

[0052] Prepare the raw materials according to the formula in Table 3;

[0053] Prepare the pre-emulsion: add water and emulsifier 1 into the monomer tank, stir evenly, then add acrylic soft monomer, vinyl acetate, versatate vinyl carbonate, functional monomer, silicone monomer and initiator 1, stir evenly to obtain the pre-emulsion.

[0054] Prepare the bottom liquid: add water and emulsifier 2 into the reactor and stir evenly, raise the temperature to about 75 degrees, then add initiator 2 and keep stirring;

[0055] Take about 5% of the total mass of the pre-emulsion in the monomer tank and add it into the reactor. After the temperature in the reactor rises to 75°C, start to add the remaining pre-emulsion at a uniform speed. The total dropping time is controlled within 4 hours. After the dropping is completed, adjust the pH value to 3 to complete the preparation of the emulsion.

[0056] Table 3

[0057]

[0058]

[0059] Example 4

[0060] A method for preparing a vac-vegetal emulsion for exterior wall coatings, specifically comprising the following steps:

[0061] Prepare the raw materials according to the formula in Table 4;

[0062] Prepare the pre-emulsion: add water and emulsifier 1 into the monomer tank, stir evenly, then add acrylic soft monomer, vinyl acetate, versatate vinyl carbonate, functional monomer, silicone monomer and initiator 1, stir evenly to obtain the pre-emulsion.

[0063] Prepare the bottom liquid: add water and emulsifier 2 into the reactor and stir evenly, heat to about 70°C, then add initiator 2 and keep stirring;

[0064] Take about 3% of the total mass of the pre-emulsion in the monomer tank and add it into the reactor. After the temperature in the reactor rises to 70°C, start to add the remaining pre-emulsion at a uniform rate. The total dropping time is controlled within 4 hours. After the dropping is completed, adjust the pH value to 3 to complete the preparation of the emulsion.

[0065] Table 4

[0066]

[0067]

[0068] Comparative Example 1

[0069] The raw materials are shown in Table 5. Compared with Example 1, the amounts of monomer components in the pre-emulsion are different, namely, 21 parts of butyl acrylate, 15 parts of vinyl acetate, and 15 parts of vinyl versatate. The rest are the same as in Example 1.

[0070] Table 5

[0071]

[0072] Comparative Example 2

[0073] The raw materials are shown in Table 6. Compared with Example 1, no organosilicon monomer is added, and the rest are the same as Example 1.

[0074] Table 6

[0075]

[0076]

[0077] Comparative Example 3

[0078] The raw materials are shown in Table 7. Compared with Example 1, no functional monomer is added, and the rest is the same as Example 1.

[0079] Table 7

[0080]

[0081] Comparative Example 4

[0082] The raw materials are shown in Table 8. Compared with Example 1, the emulsifier 1 uses a single anionic emulsifier, and the amount of DOWFAX 2A1 is 2.5 parts. The rest is the same as Example 1.

[0083] Table 8

[0084]

[0085] Comparative Example 5

[0086] The raw materials are shown in Table 9. Compared with Example 1, emulsifier 2 uses a single nonionic emulsifier, Clariant LCN287, and the amount of Clariant LCN287 is 4 parts. The rest is the same as Example 1.

[0087] Table 9

[0088]

[0089]

[0090] Comparative Example 6

[0091] Commercially available RS-2212F vinyl acetate emulsion.

[0092] Comparative Example 7

[0093] Commercially available Clariant Mowilith DM230 tertiary carbon emulsion.

[0094] Product performance testing

[0095] The performance tests of the emulsions of the embodiments of the present invention and the comparative examples are as follows.

[0096] The paint stability test is in accordance with GB / T 9756-2018;

[0097] Fire resistance, water whitening resistance, water resistance and expansion coefficient tests are in accordance with GB14907-2018;

[0098] Adhesion test is in accordance with GB / T 9286-1998.

[0099] The test results are shown in Table 10.

[0100] Table 10

[0101] Paint stability (50℃5d) Fire resistance Water whitening resistance Water resistance Adhesion Example 1 80KU Level 1 Slightly blue good 1 Example 2 82KU Level 1 Slightly blue good 1 Example 3 83KU Level 2 Blue and White Second best 1 Example 4 80KU Level 1 Light blue good 1 Comparative Example 1 82KU Level 2 Light blue good 1 Comparative Example 2 80KU Level 2 White Difference 2 Comparative Example 3 78KU Level 2 Blue and White Second best 2 Comparative Example 4 85KU Level 1 Light blue good 1 Comparative Example 5 80KU Level 1 White Difference 1 Comparative Example 6 85KU Level 1 Blue and White Second best 1 Comparative Example 7 80KU Level 2 White Difference 1

[0102] It can be seen from Table 10 that the performance of the emulsion provided by the embodiment of the present invention is better than that of the comparative example, and is better than the common vac-veolar emulsion on the market.

[0103] In Comparative Example 1, after the monomer components are changed, the amount of vinyl acetate is reduced, the amount of versatate vinyl ester is increased, the expansion coefficient of the product deteriorates, and the fire resistance deteriorates; in Comparative Example 2, the product without adding silicone monomer has poor water resistance, poor fire resistance, and improved expansion coefficient; in Comparative Example 3, no functional monomer is added, the viscosity of the product decreases, the water resistance deteriorates, the adhesion deteriorates, the fire resistance deteriorates, and the expansion coefficient deteriorates; in Comparative Example 4, emulsifier 1 uses a single emulsifier anionic emulsifier DOWFAX 2A1, and the storage stability deteriorates; in Comparative Example 5, emulsifier 2 uses a single emulsifier nonionic emulsifier Clariant LCN287, and the water resistance deteriorates and the adhesion deteriorates; Comparative Example 6 has poor storage stability and poor water resistance; Comparative Example 7 has poor fire resistance and water resistance.

[0104] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present invention (including the claims) is limited to these examples. Under the concept of the present invention, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the embodiments of the present invention as described above, which are not provided in detail for the sake of simplicity.

[0105] The embodiments of the present invention are intended to cover all such substitutions, modifications and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the embodiments of the present invention should be included in the protection scope of the present invention.

Claims

1. A vinanoic acid emulsion for exterior wall coatings, characterized in that: The vinato vacce emulsion is obtained by polymerization reaction of pre-emulsified liquid and kettle bottom liquid; The pre-emulsion comprises the following monomer components in parts by weight: 18-22 parts of acrylic soft monomer, 20-30 parts of vinyl acetate, 8-12 parts of vinyl versatate, 1-3 parts of functional monomer, and 1-3 parts of silicone monomer; The functional monomer is a hydrophilic monomer, which is a mixture of acrylic acid and acrylamide in a weight ratio of 1:1; The pre-emulsion also includes emulsifier 1, which is composed of anionic emulsifier and nonionic emulsifier; The kettle bottom liquid includes emulsifier 2, which is composed of a reactive emulsifier and a nonionic emulsifier; The anionic emulsifier is selected from DOWFAX 2A1 emulsifier of Dow Chemical or AEROSOL A-102 emulsion emulsifier of Cytec; The nonionic emulsifier is selected from Clariant LCN287, Clariant LCN118 or Clariant LCN407; The reactive emulsifier is Solvay COPS-1 emulsifier; The vac-vegetal emulsion is prepared by the following method: Preparing pre-emulsion: Mix water, emulsifier 1, acrylic soft monomer, vinyl acetate, vinyl ester carbonate, functional monomer, silicone monomer and initiator 1, and stir evenly to obtain pre-emulsion; Prepare the bottom liquid of the kettle: add water and emulsifier 2 into the reactor and stir evenly, heat up to the reaction temperature, then add initiator 2 and keep stirring; Take 1-5% of the total mass of the pre-emulsion and add it to the bottom liquid of the kettle. After the temperature in the reactor rises to the reaction temperature, start to add the remaining pre-emulsion at a uniform speed. After the addition is completed, adjust the pH value to obtain an emulsion.

2. The vac-veolar emulsion for exterior wall coating according to claim 1, characterized in that: The acrylic soft monomer is selected from butyl acrylate, isooctyl acrylate or a mixture of the two.

3. The vac-vegetal emulsion for exterior wall coating according to claim 1, characterized in that: The organic silicon monomer is selected from one or a combination of vinyl trimethoxysilane, γ-methacryloxypropyl trimethoxysilane, and γ-(2,3-epoxypropyloxy)propyl trimethoxysilane.

4. The vac-vegetal emulsion for exterior wall coating according to claim 1, characterized in that: The pre-emulsion liquid includes initiator 1, the kettle bottom liquid includes initiator 2, and the initiator 1 and initiator 2 are selected from one of ammonium persulfate, potassium persulfate and sodium persulfate.

5. The vac-vegetal emulsion for exterior wall coating according to claim 1, characterized in that: The reaction temperature is 70-75°C.

6. The vac-vegetal emulsion for exterior wall coating according to claim 1, characterized in that: When the remaining pre-emulsion is added dropwise at a uniform speed, the total reaction time of the addition is controlled to be 3-5 hours.

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