Modified titanium dioxide, latex paint and preparation method and application thereof

Abstract

The application provides a modified titanium white powder, a latex paint and a preparation method and application thereof. The modified titanium white powder comprises titanium white powder and a coating layer coated on the surface of the titanium white powder; the coating layer comprises a dopamine compound and an aromatic compound containing an acidic phenolic hydroxyl group. The dopamine compound in the coating layer can not only improve the dispersibility of the titanium white powder in a treatment liquid, but also enable the dopamine compound to form a preliminary coating on the surface of the titanium white powder, thereby further improving the dispersibility of the titanium white powder in the treatment liquid; the aromatic compound containing the acidic phenolic hydroxyl group in the coating layer enables the two to form a stable composite coating layer on the surface of the titanium white powder, thereby improving the dispersibility of the titanium white powder in the paint, and improving the washability and acid and alkali resistance of the paint.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of building coatings, in particular to a modified titanium dioxide, latex paint and a preparation method and application thereof. BACKGROUND

[0002] The application and research of titanium dioxide in latex paint show that the surface treatment of titanium dioxide needs to be carried out when it is applied, because the photochemistry of titanium dioxide leads to its reaction with organic matter contacted under light, and the easy agglomeration of titanium dioxide leads to poor dispersibility, so that surface treatment is needed. However, the existing inorganic and organic treatment methods are not firm and stable enough for the coating of titanium dioxide, and the effect is easily lost in the process of preparing latex paint.

[0003] CN113045940A discloses a latex paint for exterior wall and a preparation method thereof. The raw materials of the latex paint include the following components by weight: 380-420 parts of styrene-acrylic emulsion, 140-160 parts of coupling agent modified titanium dioxide, 114-126 parts of SiO2 powder, 5-10 parts of diammonium hydrogen citrate, 18-22 parts of film-forming aid, 155-165 parts of water, 4-8 parts of dispersant, 2-4 parts of defoaming agent, 0.5-1.5 parts of wetting agent, 10-20 parts of antifreeze, 2-2.8 parts of hydroxyethyl cellulose, 0.8-1.2 parts of multifunctional additive, 45-55 parts of kaolin, 100-120 parts of heavy calcium powder, 73-77 parts of snow white powder, and 1.8-2.2 parts of bactericide. The invention improves the compatibility of titanium dioxide with other components in the latex paint by coating the surface of titanium dioxide with a coupling agent, but the coupling agent coating is not firm enough, and the titanate coupling agent or silane coupling agent is difficult to further improve the washability and acid and alkali resistance of the latex paint.

[0004] CN109082165A discloses an environmentally friendly latex paint and a preparation method thereof, including the following raw materials by weight: 38-49 parts of polymer emulsion, 1-6 parts of defoaming agent, 2-5 parts of antifreeze, 2-9 parts of film-forming agent, 3-7 parts of thickening agent, 1-5 parts of leveling agent, 5-10 parts of talc, 12-23 parts of modified titanium dioxide, 6-14 parts of kaolin, 3-9 parts of leucite, and 0.8-1.2 parts of chitosan quaternary ammonium salt. The invention modifies titanium dioxide by using nano-sized microporous particles formed by aluminum oxide as an auxiliary component, and the titanium dioxide coated with aluminum oxide can effectively protect the photosensitivity of titanium dioxide, but this inorganic modification method makes titanium dioxide more likely to agglomerate and more difficult to disperse.

[0005] CN111393941A discloses a new type of high elasticity environment-friendly latex paint, the latex paint comprises the following components in parts by weight: water 25-40 parts, modified acrylic emulsion 25-40 parts, pigment 15-30 parts, filler 5-8 parts, water-washed kaolin 3-7 parts, heavy calcium carbonate 15-30 parts, dispersing agent 1-3 parts, defoaming agent 0.2-0.6 parts, film-forming aid 1-3 parts. The modified titanium dioxide is also under high temperature and high pH conditions to form a dense and continuous aluminum oxide film layer on the surface of titanium dioxide. The titanium dioxide coated with aluminum oxide can effectively protect the photosensitivity of titanium dioxide, but this inorganic modification method will make the titanium dioxide easy to agglomerate and more difficult to disperse.

[0006] Therefore, the present application is proposed. SUMMARY

[0007] One of the purposes of the present application is to provide a modified titanium dioxide, which comprises titanium dioxide and a coating layer coated on the surface of the titanium dioxide; the coating layer comprises dopamine compounds and aromatic compounds containing acidic phenolic hydroxyl groups. A stable composite coating layer is formed on the surface of the titanium dioxide, which not only improves the dispersibility of the titanium dioxide in the paint, but also improves the washability and acid and alkali resistance of the paint (the coating layer contains both acidic phenolic hydroxyl groups and basic amine groups).

[0008] The second purpose of the present application is to provide a preparation method of the modified titanium dioxide, which comprises the following steps: mixing dopamine compounds and a solvent to obtain a mixed solution, then dispersing titanium dioxide in the mixed solution to obtain a dispersion solution; then stirring the aromatic compounds containing acidic phenolic hydroxyl groups in the dispersion solution, filtering, to obtain the modified titanium dioxide. The preparation method further improves the firmness and stability of the coating layer on the titanium dioxide, thereby solving the problem of loss of effect during the preparation of latex paint.

[0009] The third purpose of the present application is to provide an application of the modified titanium dioxide in the preparation of latex paint.

[0010] The fourth purpose of the present application is to provide a latex paint, the preparation raw materials of the latex paint comprise the following components in parts by weight: water 20-40 parts, filler 25-45 parts, emulsion 25-35 parts and functional aid 0.1-5 parts; wherein the filler comprises the modified titanium dioxide. The addition of the modified titanium dioxide not only improves the dispersibility of the titanium dioxide in the paint, but also improves the washability and acid and alkali resistance of the paint. At the same time, by controlling the content of the modified titanium dioxide and the emulsion at a suitable value, the washability and contrast ratio of the product can be comprehensively improved.

[0011] The fifth object of the present application is to provide a preparation method of the latex paint, which comprises mixing the raw materials of the latex paint and dispersing them to be uniform.

[0012] In order to achieve the above object of the present application, the following technical solutions are adopted:

[0013] In the first aspect, the present application provides a modified titanium dioxide, which comprises titanium dioxide and a coating layer coated on the surface of the titanium dioxide; the coating layer comprises a dopamine compound and an aromatic compound containing an acidic phenolic hydroxyl group.

[0014] In the present application, the dispersibility of the titanium dioxide in the treatment liquid needs to be improved to prevent uneven treatment, so the dopamine compound is added first, which not only improves the dispersibility of the titanium dioxide in the treatment liquid, but also forms a preliminary coating of the dopamine compound on the surface of the titanium dioxide, further improving the dispersibility of the titanium dioxide in the treatment liquid; then the aromatic compound containing an acidic phenolic hydroxyl group is added for combined treatment, so that a stable composite coating layer is formed on the surface of the titanium dioxide, which not only improves the dispersibility of the titanium dioxide in the paint, but also improves the scrub resistance and acid and alkali resistance of the paint (the coating layer contains both acidic phenolic hydroxyl groups and basic amine groups).

[0015] Preferably, the ratio of the titanium dioxide, the dopamine compound and the aromatic compound containing an acidic phenolic hydroxyl group is 1:(0.03-0.06):(0.01-0.04).

[0016] For example, "0.03-0.06" can be 0.03, 0.04, 0.05, 0.06, etc.

[0017] For example, "0.01-0.04" can be 0.01, 0.02, 0.03, 0.04, etc.

[0018] Preferably, the dopamine compound is an N-acyl dopamine compound.

[0019] Preferably, the N-acyl dopamine compound is selected from any one or a combination of at least two of N-acetyl dopamine, N-coumaroyl dopamine, N-arachidonoyl dopamine, N-lauroyl dopamine, 3-methyl-N-oleoyl dopamine and N-oleoyl dopamine, preferably N-oleoyl dopamine.

[0020] Preferably, the aromatic compound containing an acidic phenolic hydroxyl group is a C1-C5 linear or branched alkyl (such as C1, C2, C3, C4, C5) substituted o-dihydroxybenzene.

[0021] Preferably, the C1-C5 linear or branched alkyl-substituted catechol is selected from any one or a combination of at least two of 3-methylcatechol, 3,5-dipropylcatechol, 3,5-diisopropylcatechol, 4-tert-butylcatechol or 3,5-di-tert-butylcatechol, preferably 3,5-di-tert-butylcatechol.

[0022] In a second aspect, the present application provides a preparation method of the modified titanium dioxide as described in the first aspect, the preparation method comprising the following steps:

[0023] The dopamine compound and the solvent are mixed to obtain a mixed solution, and then the titanium dioxide is placed in the mixed solution for dispersion treatment to obtain a dispersion solution; and then the aromatic compound containing an acidic phenolic hydroxyl group is placed in the dispersion solution for stirring treatment, and then filtered to obtain the modified titanium dioxide.

[0024] Preferably, the solvent is a basic organic solvent.

[0025] Preferably, the basic organic solvent is selected from any one or a combination of at least two of N-methylpyrrolidone, pyridine, piperidine or triethylamine, preferably pyridine.

[0026] Preferably, the mass ratio of the dopamine compound to the solvent is 1:(3-10), for example, it can be 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, etc.

[0027] Preferably, the rotation speed of the dispersion treatment is 200-600 r / min, for example, it can be 200 r / min, 300 r / min, 400 r / min, 500 r / min, 600 r / min, etc., and the time of the dispersion treatment is 30-90 min, for example, it can be 30 min, 40 min, 50 min, 60 min, 70 min, 80 min, 90 min, etc.

[0028] Preferably, the rotation speed of the stirring treatment is 300-800 r / min, for example, it can be 300 r / min, 400 r / min, 500 r / min, 600 r / min, 700 r / min, 800 r / min, etc., and the time of the stirring treatment is 3-5 h, for example, it can be 3 h, 3.5 h, 4 h, 4.5 h, 5 h, etc.

[0029] In a third aspect, the present application provides a use of the modified titanium dioxide as described in the first aspect in the preparation of a latex paint.

[0030] In a fourth aspect, the present application provides a kind of latex paint, and the raw materials for preparing the latex paint include the following components by weight fraction:

[0031] Water 20-40 parts, filler 25-45 parts, emulsion 25-35 parts and functional auxiliary 0.1-5 parts; wherein the filler comprises the modified titanium dioxide.

[0032] The content of water is 20-40 parts, for example, can be 20 parts, 22 parts, 24 parts, 26 parts, 28 parts, 30 parts, 32 parts, 34 parts, 36 parts, 38 parts, 40 parts, etc.

[0033] The content of filler is 25-45 parts, for example, can be 25 parts, 26 parts, 28 parts, 30 parts, 32 parts, 34 parts, 36 parts, 38 parts, 40 parts, 42 parts, 45 parts, etc.

[0034] The content of emulsion is 25-35 parts, for example, can be 25 parts, 26 parts, 28 parts, 30 parts, 32 parts, 35 parts, etc.

[0035] The content of functional auxiliary is 0.1-5 parts, for example, can be 0.1 parts, 0.2 parts, 0.5 parts, 1 parts, 2 parts, 3 parts, 4 parts, 5 parts, etc.

[0036] Preferably, the mass ratio of the modified titanium dioxide and the emulsion is 1:(2.2-2.5), for example, can be 1:2.2, 1:2.3, 1:2.4, 1:2.5, etc.

[0037] Because the higher the content of emulsion, the better the scrub resistance and adhesion performance, but the contrast ratio will be reduced (contrary to the effect of titanium dioxide); the higher the content of titanium dioxide, the better the contrast ratio, but the scrub resistance is reduced. Therefore, the content of titanium dioxide and emulsion in the present application is controlled in the appropriate range of 1:(2.2-2.5), which can comprehensively improve the scrub resistance and contrast ratio of the product.

[0038] Preferably, the filler further comprises heavy calcium carbonate and / or kaolin.

[0039] Preferably, the filler is composed of modified titanium dioxide, heavy calcium carbonate and kaolin with a mass ratio of (1-1.5):(1-2):(0.5-0.9);

[0040] For example, "1-1.5" can be 1, 1.1, 1.2, 1.3, 1.4, 1.5, etc.

[0041] For example, "1-2" can be 1, 1.2, 1.4, 1.6, 1.8, 2, etc.

[0042] For example, "0.5-0.9" can be 0.5, 0.6, 0.8, 0.9, etc.

[0043] Preferably, the emulsion comprises styrene-acrylic emulsion and / or pure acrylic emulsion.

[0044] Preferably, the functional adjuvant comprises any one or a combination of at least two of a dispersant, a bactericide, an antifoaming agent, a wetting agent, a thickening agent, a pH adjuster, or a film forming adjuvant.

[0045] Preferably, the dispersant is selected from any one or a combination of at least two of a modified styrene maleic acid copolymer dispersant, a modified polyether dispersant, a polyoxyethylene ether dispersant, or a modified fatty acid derivative dispersant, preferably any one or a combination of at least two of BYK 190, BYK 192, Sartomer S90, or Shin-Etsu 740W.

[0046] Preferably, the bactericide is selected from an isothiazolinone bactericide.

[0047] Preferably, the bactericide comprises a first bactericide and a second bactericide;

[0048] wherein the first bactericide is a mixture of 2-methyl-4-isothiazolin-3-one and 5-chloro-2-methyl-4-isothiazolin-3-one, and the second bactericide is a mixture of 5-chloro-2-methyl-3(2H)isothiazolone and 2-methyl 3(2H)isothiazolone ketone.

[0049] Preferably, the mass ratio of the 2-methyl-4-isothiazolin-3-one and 5-chloro-2-methyl-4-isothiazolin-3-one is 1:(1-3.5), for example, can be 1:1, 1:1.5, 1:2, 1:2.5, 1:3, 1:3.5, etc.

[0050] Preferably, the mass ratio of the 5-chloro-2-methyl-3(2H)isothiazolone and 2-methyl 3(2H)isothiazolone ketone is 1:(1.5-2.5), for example, can be 1:1.5, 1:1.8, 1:2, 1:2.2, 1:2.5, etc.

[0051] Preferably, the antifoaming agent is selected from any one or a combination of at least two of a silicone antifoaming agent, a polyether antifoaming agent, or a mineral oil antifoaming agent, preferably any one or a combination of at least two of BYK 028, Blackburn AH-034, or Shenzhen Haichuan Defoamer 121.

[0052] Preferably, the wetting agent is selected from any one or a combination of at least two of a phosphate ester wetting agent, preferably an alkyl polyoxyethylene ether phosphate ester, a phosphate ester, or an alkyl phosphate ester.

[0053] Preferably, the thickening agent is selected from any one or a combination of at least two of a cellulose thickening agent, an acrylic emulsion thickening agent, or a polyurethane modified polyether thickening agent.

[0054] Preferably, the thickening agent comprises a first thickening agent and a second thickening agent;

[0055] wherein the first thickening agent is a cellulose-based thickening agent, the second thickening agent is an acrylic emulsion-based thickening agent and / or a polyurethane modified polyether-based thickening agent.

[0056] Preferably, the cellulose-based thickening agent is hydroxyethyl cellulose.

[0057] Preferably, the acrylic emulsion-based thickening agent is HISOL D206.

[0058] Preferably, the polyether-based thickening agent is SANTOPRENE 612NC.

[0059] Preferably, the pH regulator is a basic pH regulator, preferably any one or a combination of at least two of 2-amino-2-methyl-1-propanol, ammonia water or potassium hydroxide.

[0060] Preferably, the film-forming aid is selected from any one or a combination of at least two of ethylene glycol butyl ether, alcohol ester twelve, ethylene glycol, propylene glycol or propylene glycol methyl ether.

[0061] Preferably, the raw materials for preparing the latex paint specifically include the following components in parts by weight:

[0062] A component:

[0063] water 24-36 parts, dispersant 0.2-0.6 parts, first bactericide 0.07-0.12 parts, defoaming agent 0.1-0.3 parts, wetting agent 0.1-0.3 parts, first thickening agent 0.2-0.6 parts and pH regulator 0.06-0.14 parts;

[0064] The content of water in the A component is 24-36 parts, for example, it can be 24 parts, 26 parts, 28 parts, 30 parts, 33 parts, 36 parts, etc.

[0065] The content of dispersant in the A component is 0.2-0.6 parts, for example, it can be 0.2 parts, 0.3 parts, 0.4 parts, 0.5 parts, 0.6 parts, etc.

[0066] The content of the first bactericide in the A component is 0.07-0.12 parts, for example, it can be 0.07 parts, 0.08 parts, 0.09 parts, 0.1 parts, 0.11 parts, 0.12 parts, etc.

[0067] The content of the defoaming agent in the A component is 0.1-0.3 parts, for example, it can be 0.1 parts, 0.15 parts, 0.2 parts, 0.25 parts, 0.3 parts, etc.

[0068] The content of the wetting agent in the A component is 0.1-0.3 parts, for example, it can be 0.1 parts, 0.15 parts, 0.2 parts, 0.25 parts, 0.3 parts, etc.

[0069] The content of the first thickening agent in the A component is 0.2-0.6 parts, for example, it can be 0.2 parts, 0.25 parts, 0.3 parts, 0.4 parts, 0.5 parts, 0.6 parts, etc.

[0070] The content of the pH regulator in the A component is 0.06-0.14 parts, for example, it can be 0.06 parts, 0.07 parts, 0.08 parts, 0.09 parts, 0.1 parts, 0.11 parts, 0.12 parts, 0.13 parts, 0.14 parts, etc.

[0071] The B component: modified titanium white powder 10-15 parts, heavy calcium 10-20 parts, and kaolin 5-9 parts;

[0072] The content of the modified titanium white powder in the B component is 10-15 parts, for example, it can be 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, etc.

[0073] The content of the heavy calcium in the B component is 10-20 parts, for example, it can be 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, 16 parts, 18 parts, 20 parts, etc.

[0074] The content of the kaolin in the B component is 5-9 parts, for example, it can be 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, etc.

[0075] The C component: water 1.05-2.86 parts, film-forming aid 1-1.5 parts, second bactericide 0.2-0.4 parts, emulsion 25-35 parts, and defoaming agent 0.08-0.12 parts;

[0076] The content of the water in the C component is 1.05-2.86 parts, for example, it can be 1.05 parts, 1.2 parts, 1.4 parts, 1.6 parts, 1.8 parts, 2 parts, 2.2 parts, 2.4 parts, 2.6 parts, 2.86 parts, etc.

[0077] The content of the film-forming aid in the C component is 1-1.5 parts, for example, it can be 1 part, 1.1 part, 1.2 parts, 1.3 parts, 1.4 parts, 1.5 parts, etc.

[0078] The content of the second bactericide in the C component is 0.2-0.4 parts, for example, it can be 0.2 parts, 0.25 parts, 0.3 parts, 0.35 parts, 0.4 parts, etc.

[0079] The content of the emulsion in the C component is 25-35 parts, for example, it can be 25 parts, 26 parts, 28 parts, 30 parts, 32 parts, 35 parts, etc.

[0080] The content of the defoaming agent in the C component is 0.08-0.12 parts, for example, it can be 0.08 parts, 0.09 parts, 0.1 parts, 0.11 parts, 0.12 parts, etc.

[0081] The content of the second thickening agent in the D component is 0.3-0.7 parts, for example, it can be 0.3 parts, 0.4 parts, 0.5 parts, 0.6 parts, 0.7 parts, etc.

[0082] The content of the second thickening agent in the D component is 0.3-0.7 parts, for example, it can be 0.3 parts, 0.4 parts, 0.5 parts, 0.6 parts, 0.7 parts, etc.

[0083] In a fifth aspect, the present application provides a preparation method of the latex paint according to the third aspect, which comprises the following steps:

[0084] Preferably, the preparation method of the latex paint specifically comprises the following steps:

[0085] (1) sequentially adding and mixing the raw materials in the A component in the order of water, dispersant, first bactericide, defoaming agent, wetting agent, first thickening agent, and pH regulator, and then dispersing to obtain dispersion A;

[0086] (2) sequentially adding the modified titanium dioxide, heavy calcium carbonate, and kaolin in the B component to the dispersion A, and then dispersing to obtain dispersion B;

[0087] (3) sequentially adding and mixing water, film-forming aid, second bactericide, emulsion, and defoaming agent in the C component to the dispersion B, and then dispersing to obtain dispersion C;

[0088] (4) adding and mixing the second thickening agent in the D component to the dispersion C, and then dispersing to obtain the latex paint.

[0089] Preferably, in step (1), the rotation speed of the dispersion is 500-1000 r / min, for example, it can be 500 r / min, 600 r / min, 700 r / min, 800 r / min, 900 r / min, 1000 r / min, etc., and the dispersion time is 1-10 min, for example, it can be 1 min, 2 min, 4 min, 6 min, 8 min, 10 min, etc.

[0090] Preferably, in step (2), the rotation speed of the dispersion is 1200-1500 r / min, for example, it can be 1200 r / min, 1250 r / min, 1300 r / min, 1350 r / min, 1400 r / min, 1450 r / min, 1500 r / min, etc., and the dispersion time is 20-40 min, for example, it can be 20 min, 25 min, 30 min, 35 min, 40 min, etc.

[0091] Preferably, in step (3), the dispersing speed is 700-900 r / min, for example, it can be 700 r / min, 750 r / min, 800 r / min, 850 r / min, 900 r / min, etc., and the dispersing time is 5-15 min, for example, it can be 5 min, 6 min, 8 min, 10 min, 12 min, 14 min, 15 min, etc.

[0092] Preferably, in step (4), the dispersing speed is 700-900 r / min, for example, it can be 700 r / min, 750 r / min, 800 r / min, 850 r / min, 900 r / min, etc., and the dispersing time is 5-15 min, for example, it can be 5 min, 6 min, 8 min, 10 min, 12 min, 14 min, 15 min, etc.

[0093] Compared with the prior art, the present application has the following beneficial effects:

[0094] (1) The dopamine compound in the coating layer of the present application can not only improve the dispersibility of titanium dioxide in the treatment liquid, but also form a preliminary coating on the surface of titanium dioxide, further improving the dispersibility of titanium dioxide in the treatment liquid.

[0095] (2) The aromatic compound containing acidic phenolic hydroxyl in the coating layer of the present application forms a stable composite coating on the surface of titanium dioxide, which not only improves the dispersibility of titanium dioxide in the coating, but also improves the washability and acid and alkali resistance of the coating.

[0096] (3) The present application controls the content of titanium dioxide and emulsion at a suitable value, which can comprehensively improve the washability and contrast ratio of the product. DETAILED DESCRIPTION

[0097] Unless otherwise defined herein, scientific and technical terms used in connection with the present application shall have the meanings that are commonly understood by those of ordinary skill in the art. Clear dictates of a term should be apparent; however, in the event of any latent ambiguity, definitions provided herein prevail over any dictionary or extrinsic definition. In this application, the use of "or" means "and / or" unless otherwise stated. Furthermore, the use of the term "including" as well as other forms such as "include", is non-limiting.

[0098] It should be noted that specific details are set forth in the following description in order to provide a thorough understanding of the application. However, the present application can be practiced in a variety of ways beyond those described herein, which will be apparent to those skilled in the art in light of the disclosure. Therefore, the present application is not limited to the specific embodiments disclosed below, but only by the claims.

[0099] The technical solutions of the present application will be clearly and completely described below with examples. Obviously, the described examples are part of the examples of the present application, rather than all the examples. Based on the examples in the present application, all the other examples obtained by those skilled in the art without creative labor fall within the protection scope of the present application.

[0100] The present application will be further described below by examples. Unless otherwise specified, the materials in the examples are prepared according to the existing methods, or directly purchased from the market.

[0101] Example 1

[0102] The present example provides a modified titanium white powder, which is prepared by the following steps:

[0103] (a) N-oleoyl dopamine and pyridine are mixed in a mass ratio of 1:3 to obtain a mixed solution, and then titanium white powder (titanium white powder 699) is placed in the mixed solution and dispersed at a rotating speed of 400 r / min for 50 min to obtain a uniform dispersion solution;

[0104] (b) 3,5-di-tert-butylcatechol is added to the above dispersion solution, stirred at a rotating speed of 500 r / min for 3 h, and filtered to obtain the modified titanium white powder;

[0105] The mass ratio of N-oleoyl dopamine, 3,5-di-tert-butylcatechol and titanium white powder is 0.03:0.04:1.

[0106] Example 2

[0107] The present example provides a modified titanium white powder, which is prepared by the following steps:

[0108] (a) N-oleoyl dopamine and pyridine are mixed in a mass ratio of 1:6 to obtain a mixed solution, and then titanium white powder (titanium white powder 699) is placed in the mixed solution and dispersed at a rotating speed of 200 r / min for 90 min to obtain a uniform dispersion solution;

[0109] (b) 3,5-di-tert-butylcatechol is added to the above dispersion solution, stirred at a rotating speed of 400 r / min for 4 h, and filtered to obtain the modified titanium white powder;

[0110] The mass ratio of N-oleoyl dopamine, 3,5-di-tert-butylcatechol and titanium white powder is 0.04:0.02:1.

[0111] Example 3

[0112] The present example provides a modified titanium white powder, which is prepared by the following steps:

[0113] (a) mixing N-oleoyl dopamine and pyridine at a mass ratio of 1:10 to obtain a mixed solution, and then placing titanium dioxide (titanium dioxide 699) in the mixed solution and dispersing at a rotation speed of 600 r / min for 30 min to obtain a uniform dispersion solution;

[0114] (b) adding 3,5-di-tert-butylcatechol to the dispersion solution and stirring at a rotation speed of 300 r / min for 5 h, and then filtering to obtain the modified titanium dioxide;

[0115] wherein the mass ratio of N-oleoyl dopamine, 3,5-di-tert-butylcatechol and titanium dioxide is 0.06:0.04:1.

[0116] Example 4

[0117] This example provides a modified titanium dioxide, which is different from example 2 only in that N-oleoyl dopamine is replaced by an equal mass of 3-methyl-N-oleoyl dopamine, and other steps are the same as those in example 2.

[0118] Example 5

[0119] This example provides a modified titanium dioxide, which is different from example 2 only in that N-oleoyl dopamine is replaced by an equal mass of 3-methyl-N-oleoyl dopamine, and other steps are the same as those in example 2.

[0120] Example 6

[0121] This example provides a modified titanium dioxide, which is different from example 2 only in that 3,5-di-tert-butylcatechol is replaced by an equal mass of 3,5-di-tert-butylcatechol, and other steps are the same as those in example 2.

[0122] Example 7

[0123] This example provides a modified titanium dioxide, which is different from example 2 only in that N-oleoyl dopamine is replaced by an equal mass of 3-methyl-N-oleoyl dopamine, and other steps are the same as those in example 2.

[0124] Comparative Example 1

[0125] This comparative example provides a titanium dioxide, which is an unmodified titanium dioxide 699.

[0126] Comparative Example 2

[0127] This comparative example provides a modified titanium dioxide, which is prepared by the following steps:

[0128] mixing N-oleoyl dopamine and pyridine to obtain a mixed solution, and then placing titanium dioxide (titanium dioxide 699) in the mixed solution and stirring at a rotation speed of 400 r / min for 4 h, and then filtering to obtain the modified titanium dioxide;

[0129] The mass ratio of N-oleoyl dopamine to titanium dioxide is 0.04:1.

[0130] Comparative Example 3

[0131] The present comparative example provides a modified titanium dioxide prepared by the following steps:

[0132] (a) mixing titanium dioxide (titanium dioxide 699) and pyridine at a mass ratio of 1:6 to obtain a mixed solution, dispersing at a rotation speed of 200 r / min for 90 min to obtain a uniform dispersion solution;

[0133] (b) adding 3,5-di-tert-butylcatechol to the above dispersion solution, stirring at a rotation speed of 400 r / min for 4 h, and filtering to obtain the modified titanium dioxide;

[0134] The mass ratio of N-oleoyl dopamine, 3,5-di-tert-butylcatechol, and titanium dioxide is 0.02:1.

[0135] Comparative Example 4

[0136] The present comparative example provides a modified titanium dioxide prepared by the following steps:

[0137] Mixing N-oleoyl dopamine, 3,5-di-tert-butylcatechol, and pyridine to obtain a mixed solution, and then placing titanium dioxide (titanium dioxide 699) in the mixed solution, stirring at a rotation speed of 400 r / min for 4 h, and filtering to obtain the modified titanium dioxide;

[0138] The mass ratio of N-oleoyl dopamine, 3,5-di-tert-butylcatechol, and titanium dioxide is 0.04:0.02:1.

[0139] Application Examples 1-3

[0140] The present application example provides three kinds of latex paint, and the latex paint of application examples 1-3 specifically comprises the following components:

[0141]

[0142]

[0143] The preparation method of the latex paint specifically comprises the following steps:

[0144] (1) The raw materials in component A are sequentially added and mixed in the order of water, dispersant, first bactericide, defoaming agent, wetting agent, first thickening agent, and pH adjuster, and then dispersed at 500 r / min for 5 min to obtain dispersion solution A;

[0145] (2) After adding the modified titanium dioxide in the B component, the heavy calcium carbonate and the kaolin clay in the dispersion liquid A successively, dispersing at 1400 r / min for 30 min, dispersion liquid B was obtained;

[0146] (3) After adding the water, the film forming aid, the second bactericide, the emulsion and the defoaming agent in the C component in the dispersion liquid B successively, dispersing at 800 r / min for 10 min, dispersion liquid C was obtained;

[0147] (4) After adding the second thickening agent in the D component in the dispersion liquid C, dispersing at 800 r / min for 10 min, the latex paint was obtained.

[0148] Application Example 4

[0149] The application example provides a latex paint, which is different from the application example 2 only in that the modified titanium dioxide prepared in the example 2 is replaced by the modified titanium dioxide prepared in the example 4 with the same quality, and other components are defined to be completely the same as the preparation steps and the application example 2.

[0150] Application Example 5

[0151] The application example provides a latex paint, which is different from the application example 2 only in that the modified titanium dioxide prepared in the example 2 is replaced by the modified titanium dioxide prepared in the example 5 with the same quality, and other components are defined to be completely the same as the preparation steps and the application example 2.

[0152] Application Example 6

[0153] The application example provides a latex paint, which is different from the application example 2 only in that the modified titanium dioxide prepared in the example 2 is replaced by the modified titanium dioxide prepared in the example 6 with the same quality, and other components are defined to be completely the same as the preparation steps and the application example 2.

[0154] Application Example 7

[0155] The application example provides a latex paint, which is different from the application example 2 only in that the modified titanium dioxide prepared in the example 2 is replaced by the modified titanium dioxide prepared in the example 7 with the same quality, and other components are defined to be completely the same as the preparation steps and the application example 2.

[0156] Application Examples 8-13

[0157] The application examples 8-13 provide latex paints with different formulas, which are different from the application example 2 only in that the proportions of the water, the titanium dioxide and the emulsion are different, and other components are defined to be completely the same as the preparation steps and the application example 2, and the specific embodiments are as follows:

[0158]

[0159] Comparative Application Example 1

[0160] The present comparative application provides a latex paint, which is different from the application example 2 only in that the modified titanium dioxide prepared in the example 2 is replaced by the titanium dioxide provided by the comparative example 1 in the same mass, and other components are defined in the same way as the preparation steps and the application example 2.

[0161] Comparative application example 2

[0162] The present comparative application provides a latex paint, which is different from the application example 2 only in that the modified titanium dioxide prepared in the example 2 is replaced by the N-oleoyl dopamine single-modified titanium dioxide provided by the comparative example 2 in the same mass, and other components are defined in the same way as the preparation steps and the application example 2.

[0163] Comparative application example 3

[0164] The present comparative application provides a latex paint, which is different from the application example 2 only in that the modified titanium dioxide prepared in the example 2 is replaced by the 3,5-di-tert-butyl catechol single titanium dioxide provided by the comparative example 3 in the same mass, and other components are defined in the same way as the preparation steps and the application example 2.

[0165] Comparative application example 4

[0166] The present comparative application provides a latex paint, which is different from the application example 2 only in that the modified titanium dioxide prepared in the example 2 is replaced by the modified titanium dioxide provided by the comparative example 4 in the same mass, and other components are defined in the same way as the preparation steps and the application example 2.

[0167] Test example 1

[0168] In-can performance

[0169] Test sample: the latex paints provided by the application examples 1-7 and the latex paints provided by the comparative application examples 1-4; the specific test standards and test results are shown in the following table 1 and table 2:

[0170] Table 1

[0171]

[0172]

[0173] Table 2

[0174]

[0175]

[0176] From the test data in table 1 and table 2, it can be seen that the latex paint added with the modified titanium dioxide of the present application in the application examples 1-7 has no hard block, is in a uniform state after stirring, has a fineness of less than 35 μm, and has no heterogeneity and no deterioration in the freeze-thaw cycle at low temperature, and the in-can state of the heat storage stability at high temperature is more than 8 levels, which is obviously excellent in dispersion and stability in the tank.

[0177] The comparative application example 7 directly added unmodified titanium white powder in the latex paint, which was easily agglomerated, resulting in poor dispersion, a particle size of 42 μm, large particles, and low stability. In the freeze-thaw cycle at low temperature, moderate heterogeneity and slight metamorphism occurred. Although the comparative application examples 8-10 added modified titanium white powder, they did not use the N-oleoyl dopamine coating and 3,5-di-tert-butyl catechol post-treatment method of the present application, so the coating of the titanium white powder was not strong and stable. Therefore, although the uniformity and stability were improved, the latex paint of example 2 still showed slight heterogeneity.

[0178] Test example 2

[0179] In-can performance

[0180] Test sample: latex paint provided by application examples 1-13 and latex paint provided by comparative application examples 1-4;

[0181] The specific test standards and test results are shown in Tables 3 and 4:

[0182] Table 3

[0183]

[0184]

[0185] Table 4

[0186]

[0187]

[0188] As can be seen from the test data in Tables 3 and 4, the latex paint of application examples 1-7 added with the modified titanium white powder of the present application shows excellent performance after film formation. The modified titanium white powder also improves the wash resistance and acid and alkali resistance of the coating (the coating layer contains both acidic phenolic hydroxyl groups and basic amine groups).

[0189] As can be seen from the comparison of application example 2 and comparative application examples 1-6, the higher the emulsion content, the better the wash resistance and adhesion performance, but the contrast ratio will decrease (opposite to the effect of titanium white powder); the higher the titanium white powder content, the better the contrast ratio, but the wash resistance decreases. Therefore, the content of titanium white powder and emulsion is controlled in the appropriate range of 1:(2.2-2.5) to comprehensively improve the wash resistance and contrast ratio of the product.

[0190] The comparative application examples 7-9 directly add unmodified titanium white powder in the latex paint, or only use acid phenolic hydroxyl modification, only use alkaline amine modification, and the prepared latex paint has poor scrub resistance and alkali resistance; although the comparative application example 10 simultaneously uses acid and base substances for modification, however, the modification treatment method makes the coating layer complete coating in the preparation process, but the coating of titanium white powder is not firm and stable, and is easily detached in the preparation process of the latex paint, so although the effect is obviously improved compared with the comparative application examples 7-9, the coating film performance is still different from the coating film performance of the preferred technical solution of the present application.

[0191] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solution deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A modified titanium dioxide, characterized in that, The modified titanium dioxide includes titanium dioxide and a coating layer on the surface of the titanium dioxide; the coating layer includes dopamine compounds and aromatic compounds containing acidic phenolic hydroxyl groups; The ratio of titanium dioxide, dopamine compounds, and aromatic compounds containing acidic phenolic hydroxyl groups is 1:(0.03-0.06):(0.01-0.04). The dopamine compounds are N -Acyl dopamine compounds; the N -Acyldopamine compounds are selected from N -Arachidyl dopamine, N -Lauroyl dopamine, 3-methyl- N -Oleidoyl dopamine, N -Any one or at least a combination of two of oleoyl dopamine; Wherein, the aromatic compound containing an acidic phenolic hydroxyl group is a C1-C5 straight-chain or branched alkyl-substituted catechol; the C1-C5 straight-chain or branched alkyl-substituted catechol is selected from any one or a combination of at least two of 3-methylcatechol, 3,5-dipropylcatechol, 3,5-diisopropylcatechol, 4-tert-butylcatechol or 3,5-ditert-butylcatechol; The modified titanium dioxide is prepared by the following steps: A dopamine compound and a solvent are mixed to obtain a mixture, and titanium dioxide is then placed in the mixture for dispersion treatment to obtain a dispersion. An aromatic compound containing acidic phenolic hydroxyl groups is then placed in the dispersion for stirring treatment, and the mixture is filtered to obtain the modified titanium dioxide.

2. The modified titanium dioxide according to claim 1, characterized in that, The dopamine-like compound is N -Oleidoyl dopamine.

3. The modified titanium dioxide according to claim 1, characterized in that, The aromatic compound containing an acidic phenolic hydroxyl group is 3,5-di-tert-butylcatechol.

4. A method for preparing modified titanium dioxide according to any one of claims 1 to 3, characterized in that, The preparation method includes the following steps: A dopamine compound and a solvent are mixed to obtain a mixture, and titanium dioxide is then placed in the mixture for dispersion treatment to obtain a dispersion. An aromatic compound containing acidic phenolic hydroxyl groups is then placed in the dispersion for stirring treatment, and the mixture is filtered to obtain the modified titanium dioxide.

5. The method for preparing modified titanium dioxide according to claim 4, characterized in that, The solvent is an alkaline organic solvent.

6. The method for preparing modified titanium dioxide according to claim 5, characterized in that, The alkaline organic solvent is selected from N -Methylpyrrolidone, pyridine, piperidine, or triethylamine, or a combination of at least two of these.

7. The method for preparing modified titanium dioxide according to claim 6, characterized in that, The alkaline organic solvent is pyridine.

8. The method for preparing modified titanium dioxide according to claim 4, characterized in that, The mass ratio of the dopamine compound to the solvent is 1:(3-10).

9. The method for preparing modified titanium dioxide according to claim 4, characterized in that, The dispersion process is carried out at a rotation speed of 200-600 r / min and for a duration of 30-90 min.

10. The method for preparing modified titanium dioxide according to claim 4, characterized in that, The stirring speed is 300-800 r / min, and the stirring time is 3-5 h.

11. The use of the modified titanium dioxide according to any one of claims 1 to 3 in the preparation of latex paint.

12. A latex paint, characterized in that, The raw materials for preparing the latex paint include the following components by weight: The mixture comprises 20-40 parts water, 25-45 parts filler, 25-35 parts emulsion, and 0.1-5 parts functional additives; wherein the filler comprises the modified titanium dioxide as described in any one of claims 1 to 3.

13. The latex paint according to claim 12, characterized in that, The mass ratio of the modified titanium dioxide to the emulsion is 1:(2.2-2.5).

14. The latex paint according to claim 12, characterized in that, The filler also includes heavy calcium carbonate and / or kaolin.

15. The latex paint according to claim 12, characterized in that, The filler is composed of modified titanium dioxide, heavy calcium carbonate and kaolin in a mass ratio of (1-1.5):(1-2):(0.5-0.9).

16. The latex paint according to claim 12, characterized in that, The emulsion includes styrene-acrylic emulsion and / or pure acrylic emulsion.

17. The latex paint according to claim 12, characterized in that, The functional additives include any one or a combination of at least two of the following: dispersants, bactericides, defoamers, wetting agents, thickeners, pH adjusters, or film-forming aids.

18. The latex paint according to claim 17, characterized in that, The dispersant is selected from any one or a combination of at least two of the following: modified styrene-maleic acid copolymer dispersants, modified polyether dispersants, polyoxyethylene ether dispersants, or modified fatty acid derivative dispersants.

19. The latex paint according to claim 17, characterized in that, The bactericide is selected from isothiazolinone bactericides.

20. The latex paint according to claim 17 or 19, characterized in that, The bactericide includes a first bactericide and a second bactericide; The first bactericide is a mixture of 2-methyl-4-isothiazolin-3-one and 5-chloro-2-methyl-4-isothiazolin-3-one, and the second bactericide is a mixture of 5-chloro-2-methyl-3(2H)isothiazolinone and 2-methyl-3(2H)isothiazolinone.

21. The latex paint according to claim 20, characterized in that, The mass ratio of 2-methyl-4-isothiazolin-3-one to 5-chloro-2-methyl-4-isothiazolin-3-one is 1:(1-3.5).

22. The latex paint according to claim 21, characterized in that, The mass ratio of 5-chloro-2-methyl-3(2H)isothiazolidinone to 2-methyl-3(2H)isothiazolidinone is 1:(1.5-2.5).

23. The latex paint according to claim 17, characterized in that, The defoamer is selected from any one or a combination of at least two of the following: silicone defoamer, polyether defoamer, or mineral oil defoamer.

24. The latex paint according to claim 17, characterized in that, The wetting agent is selected from phosphate ester wetting agents.

25. The latex paint according to claim 24, characterized in that, The wetting agent is any one or a combination of at least two of alkyl polyoxyethylene ether phosphate or alkyl phosphate.

26. The latex paint according to claim 17, characterized in that, The thickener is selected from any one or a combination of at least two of the following: cellulose thickeners, acrylic emulsion thickeners, or polyurethane modified polyether thickeners.

27. The latex paint according to claim 26, characterized in that, The thickener includes a first thickener and a second thickener; The first thickener is a cellulose-based thickener, and the second thickener is an acrylic emulsion thickener and / or a polyurethane-modified polyether thickener.

28. The latex paint according to claim 27, characterized in that, The cellulose-based thickener is hydroxyethyl cellulose.

29. The latex paint according to claim 17, characterized in that, The pH adjuster is an alkaline pH adjuster.

30. The latex paint according to claim 29, characterized in that, The pH adjuster is any one or a combination of at least two of 2-amino-2-methyl-1-propanol, ammonia, or potassium hydroxide.

31. The latex paint according to claim 17, characterized in that, The film-forming aid is selected from any one or a combination of at least two of ethylene glycol butyl ether, dodecyl alcohol ester, ethylene glycol, propylene glycol, or propylene glycol methyl ether.

32. The latex paint according to claim 12, characterized in that, The raw materials for preparing the latex paint specifically include the following components by weight: Component A: 24-36 parts water, 0.2-0.6 parts dispersant, 0.07-0.12 parts primary bactericide, 0.1-0.3 parts defoamer, 0.1-0.3 parts wetting agent, 0.2-0.6 parts primary thickener, and 0.06-0.14 parts pH adjuster; Component B: 10-15 parts modified titanium dioxide, 10-20 parts heavy calcium carbonate, and 5-9 parts kaolin; Component C: 1.05-2.86 parts water, 1-1.5 parts film-forming aid, 0.2-0.4 parts secondary bactericide, 25-35 parts emulsion, and 0.08-0.12 parts defoamer; Component D: 0.3-0.7 parts of the second thickener.

33. A method for preparing latex paint according to any one of claims 12 to 32, characterized in that, The preparation method is as follows: after mixing the raw materials for preparing latex paint, disperse them until uniform to obtain the latex paint.

34. A method for preparing latex paint according to claim 33, characterized in that, The preparation method of the latex paint specifically includes the following steps: (1) The raw materials in component A are added in the order of water, dispersant, first bactericide, defoamer, wetting agent, first thickener and pH adjuster, mixed and dispersed to obtain dispersion A; (2) Modified titanium dioxide, heavy calcium carbonate and kaolin from component B were added sequentially to dispersion A and then dispersed to obtain dispersion B; (3) Add water, film-forming aid, secondary bactericide, emulsion and defoamer from component C to dispersion B in sequence, mix and disperse to obtain dispersion C; (4) After adding the second thickener from component D to dispersion C and mixing, disperse to obtain the latex paint.

35. The method for preparing latex paint according to claim 34, characterized in that, In step (1), the dispersion rotation speed is 500-1000 r / min, and the dispersion time is 1-10 min.

36. The method for preparing latex paint according to claim 34, characterized in that, In step (2), the dispersion rotation speed is 1200-1500 r / min, and the dispersion time is 20-40 min.

37. The method for preparing latex paint according to claim 34, characterized in that, In step (3), the dispersion rotation speed is 700-900 r / min, and the dispersion time is 5-15 min.

38. The method for preparing latex paint according to claim 34, characterized in that, In step (4), the dispersion rotation speed is 700-900 r / min, and the dispersion time is 5-15 min.

Images