Acrylate emulsion for ceramic tile back adhesive as well as preparation method and application of acrylate emulsion

Abstract

The invention discloses an acrylate emulsion for a ceramic tile back adhesive, a preparation method and application thereof, the acrylate emulsion is polymerized by adopting a core-shell emulsion polymerization technology, and a core layer and a shell layer in core-shell emulsion particles respectively account for 25%-50% and 50%-75% of the total mass of the polymer. The acrylate emulsion is large in particle size, milky white, stable, high in emulsion viscosity, beneficial to construction and low in emulsion solid content, the formula cost can be effectively reduced, and the product competitiveness can be improved; the ceramic tile back adhesive prepared from the adhesive has high initial viscosity and high bonding strength, can still keep high bonding strength after being soaked in water, is non-toxic and environment-friendly, is convenient to construct, and is an ideal bonding material.

Description

Technical Field

[0001] The invention relates to the technical field of coating preparation, and in particular to an acrylic emulsion for tile back glue, a preparation method and application thereof. Background Art

[0002] With the rapid development of building interior and exterior wall finishes, a large number of low or even zero water absorption and large-sized finishing materials have emerged, such as ceramic thin plate tiles, vitrified tiles, polished tiles, microcrystalline stones, antique tiles, artificial marble, etc. The paving materials have also developed from cement mortar to tile adhesives and tile adhesives. As the water absorption rate of tiles becomes lower and lower, the pasting surface becomes smoother and denser, and the traditional paving can no longer meet the bonding requirements. In particular, vitrified tiles and polished tiles have high material strength, are sensitive to temperature changes, and the temperature difference is not synchronized. Different from the thermal expansion coefficient of cement, large-sized tiles will have temperature stress after paving. Seasonal temperature oscillations will cause the bonding strength to decrease, destroy the bonding strength between the brick body and the substrate, and cause hollowing between the tiles and the structural layer due to poor bonding and bonding. Cement mortar is a rigid material with good durability but low bonding strength, and cannot resist shedding caused by thermal expansion and contraction or wet expansion and dry shrinkage. The laying of this type of finishing material requires that the tile adhesive has strong adhesion and sufficient flexibility to withstand the damage caused by climate change and the slight vibration of high-rise buildings. For polished tiles, vitrified tiles, and architectural thin tiles with low water absorption and large sizes, C2 grade tile adhesive is recommended, but the overall laying cost is high. In addition, most domestic tile adhesive manufacturers have been manufacturing products according to the C1 standard, and some cannot even meet the C1 standard, which leads to hollowing and falling off of tiles with low water absorption.

[0003] Tile adhesive, as a new type of tile paving material applied to the back of tiles, can not only effectively reduce the surface tension of the tile surface, but also improve the bonding ability between the tile and the cement mortar layer, effectively solving the problems of hollowing and tile falling off, and extending the service life of the tiles.

[0004] There are many types of single-component tile adhesives commonly used in the market, but they all have the problem of not being able to take into account both high initial adhesion and high bonding strength characteristics. For example, the tile adhesive of the modified pressure-sensitive adhesive system has a high initial adhesion, but this type of adhesive often has disadvantages such as low bonding strength, poor water resistance, and soft coating in actual use. It also has low cohesion and poor impact resistance when applied on vitrified tiles. The existing high-bonding strength tile adhesive has a general initial adhesion, and due to its rigidity, it has a poor anti-vibration effect, and often has a poor brick-breaking effect. After the tiles are laid, if vibration is generated by drilling holes during decoration, it is easy for the tiles to fall off.

[0005] At present, some tile back adhesives with medium initial adhesion and bonding strength have been launched on the market. However, due to the characteristics of acrylic resin being hot sticky and cold brittle, there are still few acrylate one-component back adhesive products with high initial adhesion and bonding strength on the market. If the glass transition temperature of the acrylate emulsion is ≤ -40°C, the rigidity of the macromolecular chain is insufficient, and it is difficult for the tile back adhesive to achieve high bonding strength. If the glass transition temperature is increased, the bonding strength of the tile back adhesive will increase, but the initial adhesion will decrease, which makes it difficult for the tile back adhesive to have both high initial adhesion and high bonding strength.

[0006] Chinese Patent CN114634592A discloses a preparation method and application of an acrylic high-initial-adhesion and high-strength back adhesive emulsion, including: preparation of emulsion; preparation of seed emulsion; polymerization; elimination; the preparation process is simple, and the product is green and environmentally friendly. By introducing special functional monomers, molecular weight adjustment, and preparation process, the excellent molecular weight control after resin film formation can be changed, and the molecular surface polarity can be improved, solving the relationship between the initial adhesion and bonding strength of the back adhesive emulsion on the market at present, ensuring excellent pressure-sensitive adhesive initial adhesion effect, excellent bonding strength, and water resistance of the clear paint film.

[0007] Chinese Patent CN112778450A discloses a tile back adhesive emulsion with high initial adhesion and high bonding strength and its preparation method. Among them, the monomer raw materials of the tile back adhesive emulsion include: tridecyl methacrylate, butyl acrylate, 2-ethylhexyl acrylate, acrylic acid, hydroxyethyl acrylate, vinyltrimethoxysilane, and methacrylamide ethyl ethylene urea. Using tridecyl methacrylate, butyl acrylate, and 2-ethylhexyl acrylate as the main monomers can ensure high initial adhesion performance of the tile back adhesive emulsion, while also ensuring certain bonding strength and water resistance. And acrylic acid, hydroxyethyl acrylate, vinyltrimethoxysilane, and methacrylamide ethyl ethylene urea are all functional monomers. Through the synergistic effect of each functional monomer, the rigidity and intermolecular force of the tile back adhesive emulsion are improved, thereby further improving the bonding strength of the tile back adhesive emulsion.

[0008] Chinese Patent CN114591462A discloses a hydrophobic high-strength and high-adhesion composite tile back adhesive and its preparation method, which is prepared by copolymerization reaction of a combined monomer composed of styrene, acrylic alkyl ester, functional monomer, silane coupling agent, initiator, etc. with water as the medium. The tile back adhesive prepared by its invention takes into account both bonding strength and initial adhesion, and has good wet adhesion and water resistance.

[0009] Chinese Patent CN111154026A discloses a tertiary carbonate organosilicon propyl modified copolymer emulsion for environmentally friendly tile back glue. The invention adopts a tertiary carbonate organosilicon propyl modified copolymer emulsion for environmentally friendly tile back glue, which is polymerized from acrylate, tertiary carbonate, styrene and organosilicon polymer. The material is environmentally friendly and meets the requirements of environmental protection standards. Experimental studies show that it has high bonding strength, is not easy to have hollowing, is not easy to drop bricks, is convenient for construction, and at the same time has good water resistance, freeze-thaw resistance, aging resistance and other properties.

[0010] Currently, with the trend of decoration and market demand for cost requirements, it is required that the emulsion for tile back glue has a low solid content (such as 45%), a moderate particle size (about 200nm), a stable emulsion viscosity and can be freely adjusted. The tile back glue prepared from it still has high initial tack and high bonding strength at the same time, so as to reduce the formulation cost and improve the product competitiveness. Summary of the Invention

[0011] In view of this, the main purpose of the present invention is to provide an acrylate emulsion for tile back glue, a preparation method and its application. The emulsion for tile back glue of the present invention has a low solid content, a moderate particle size, a stable emulsion viscosity and can be freely adjusted, has excellent initial tack and bonding strength, and at the same time improves the comprehensive performance of the tile back glue.

[0012] To achieve the above-mentioned invention purpose, the present invention adopts the following technical solutions:

[0013] The first aspect of the present invention provides an acrylate emulsion for tile back glue, which comprises the following components in parts by mass or is prepared by core-shell emulsion polymerization from raw materials including the following components in parts by mass:

[0014] 1) Core layer emulsion polymerization, including

[0015] Component a): at least one monovinyl aromatic monomer and at least one C1-C4-alkyl ester of methacrylic acid and mixtures thereof, 5-15 parts, such as 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, etc., preferably 10-15 parts;

[0016] Component b): at least one C2-C 10 -alkyl ester of acrylic acid, 50-70 parts, such as 50 parts, 53 parts, 55 parts, 57 parts, 60 parts, 62 parts, 65 parts, 68 parts, 70 parts, etc., preferably 55-70 parts;

[0017] Component c): at least one α,β-monoethylenically unsaturated C3-C6-monocarboxylic acid, 2.5-7.5 parts, such as 2.5 parts, 3 parts, 3.5 parts, 4 parts, 4.5 parts, 5 parts, 5.5 parts, 6 parts, 6.5 parts, 7 parts, 7.5 parts, etc., preferably 3.5-6.5 parts;

[0018] Component d): at least one monoethylenically unsaturated sulfonic acid and its salts, 0.1 - 1.0 parts, such as 0.1 part, 0.2 parts, 0.3 parts, 0.4 parts, 0.5 parts, 0.6 parts, 0.7 parts, 0.8 parts, 0.9 parts, 1.0 part, etc., preferably 0.2 - 0.8 parts;

[0019] Component e): at least one allyl compound as a chain transfer agent, 0.1 - 0.5 parts, such as 0.1 part, 0.2 parts, 0.3 parts, 0.4 parts, 0.5 part, etc., preferably 0.1 - 0.3 parts;

[0020] Component f): at least one monomer having a monoethylenically unsaturated double bond and a hydrolyzable Si - organic bond, 0.05 - 0.2 parts, such as 0.05 part, 0.08 part, 0.1 part, 0.13 part, 0.15 part, 0.18 part, 0.2 part, etc., preferably 0.05 - 0.15 parts;

[0021] 2) Shell emulsion polymerization, including

[0022] Component a): at least one mono - vinyl aromatic monomer and at least one C1 - C4 - alkyl ester of methacrylic acid and their mixture, 10 - 20 parts, such as 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, 16 parts, 17 parts, 18 parts, 19 parts, 20 parts, etc., preferably 15 - 20 parts;

[0023] Component b): at least one C2 - C 10 -alkyl ester of acrylic acid, 90 - 120 parts, such as 90 parts, 95 parts, 100 parts, 105 parts, 110 parts, 115 parts, 120 parts, etc., preferably 100 - 120 parts;

[0024] Component c): at least one α,β - monoethylenically unsaturated C3 - C6 - monocarboxylic acid, 0.2 - 1.0 parts, such as 0.2 parts, 0.3 parts, 0.4 parts, 0.5 parts, 0.6 parts, 0.7 parts, 0.8 parts, 0.9 parts, 1.0 part, etc., preferably 0.2 - 0.8 parts;

[0025] Component e): at least one allyl compound as a chain transfer agent, 0.05 - 0.25 parts, such as 0.05 part, 0.1 part, 0.15 part, 0.2 part, 0.25 part, etc., preferably 0.1 - 0.2 parts;

[0026] Component f): at least one monomer having a monoethylenically unsaturated double bond and a hydrolyzable Si - organic bond, 0.05 - 0.2 parts, such as 0.05 part, 0.1 part, 0.15 part, 0.2 part, etc., preferably 0.05 - 0.15 parts;

[0027] Among them, the core layer and the shell layer in the core-shell latex particles respectively account for 25%-50% and 50%-75% of the total mass of the polymer. For example, the core layer accounts for 25%, 30%, 35%, 40%, 45%, 50%, etc., preferably 25%-45%; the shell layer accounts for 50%, 55%, 60%, 65%, 70%, 75%, etc., preferably 55%-75%.

[0028] In a preferred embodiment, the monovinyl aromatic monomer of component a) includes one or more of styrene, 2-methylstyrene, 4-methylstyrene, 2-(n-butyl)styrene, 4-(n-butyl)styrene, and 4-(n-decyl)styrene, preferably styrene.

[0029] In a preferred embodiment, the C1-C4-alkyl ester of methacrylic acid of component a) is selected from one or more of methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isobutyl methacrylate, n-butyl methacrylate, sec-butyl methacrylate, isobutyl methacrylate, and tert-butyl methacrylate, preferably methyl methacrylate.

[0030] In component a) of the present invention, in the mixture of at least one monovinyl aromatic monomer and at least one C1-C4-alkyl ester of methacrylic acid, the ratio between the two is not particularly limited and can be any ratio. Preferably, the C1-C4-alkyl ester of methacrylic acid accounts for 10%-40 wt%, for example, methyl methacrylate in component a) accounts for 10%-40 wt%.

[0031] In a preferred embodiment, the C2-C 10 -alkyl ester of acrylic acid of component b) includes one or more of ethyl acrylate, butyl acrylate, n-hexyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate, 2-propylheptyl acrylate, and isooctyl acrylate, preferably butyl acrylate and isooctyl acrylate.

[0032] In a preferred embodiment, the α,β-monounsaturated C3-C6 monocarboxylic acid of component c) is selected from one or more of acrylic acid, methacrylic acid, crotonic acid, 2-ethylacrylic acid, 2-propylacrylic acid, 2-acryloyloxyacetic acid, and 2-methacryloyloxyacetic acid, preferably acrylic acid and methacrylic acid.

[0033] In a preferred embodiment, the monounsaturated sulfonic acid and its salt of component d) are selected from one or more of vinyl sulfonic acid, allyl sulfonic acid, 2-sulfoethyl acrylate, 2-sulfoethyl methacrylate, 3-sulfopropyl acrylate, 3-sulfopropyl methacrylate, 2-hydroxy-3-acryloyloxypropyl sulfonic acid, 2-hydroxy-3-methacryloyloxypropyl sulfonic acid, styrene sulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid, and their salts, preferably their sodium salts.

[0034] In a preferred embodiment, the monoethylenically unsaturated sulfonic acid and its salt of component d) include one or more of styrenesulfonic acid and its salt, 2-acrylamido-2-methylpropanesulfonic acid and its salt, preferably their sodium salts.

[0035] In a preferred embodiment, the allyl compound chain transfer agent of component e) has the following structural formula:

[0036] Wherein:

[0037]

[0038] X is selected from any one of hydrogen, CN, optionally substituted aryl, COOH, COOR and halogen;

[0039] Y is selected from any one of hydrogen, C1-C6 alkyl, C1-C6 alkyl substituted by one or more substituents selected from hydroxyl, amino, C1-C6 alkoxy, C1-C6 alkoxycarbonyl, halogen, CN, optionally substituted aryl, C1-C6 alkenyl and C1-C6 alkynyl;

[0040] R 1 and R 2 may be the same or different and are selected from C1-C 18 alkyl, C1-C 12 alkyl substituted by substituents selected from hydroxyl, C1-C6 acyloxy, C1-C6 alkoxy, amino, halogen, optionally substituted aryl, CN and NCO;

[0041] R 3 and R 4 may be the same or different and are selected from any one of hydrogen, C1-C4 alkyl and halogen.

[0042] In the present invention, the allyl compound chain transfer agent of component e) can be prepared with reference to Patent CN1138320A, and the related prior art can be incorporated into the present invention.

[0043] In a preferred embodiment, the monomer containing a monoethylenically unsaturated double bond and a hydrolyzable Si-organic bond of component f) includes one or more of vinyltrialkoxysilane, alkylvinyldialkoxysilane and (meth)acryloxyalkyltrialkoxysilane.

[0044] In a preferred embodiment, the monomer containing a monounsaturated double bond and a hydrolyzable Si-organic bond in component f) includes one or more of vinyltrimethoxysilane, methylvinyldialkoxysilane, (meth)acryloxypropyltrimethoxysilane, and (meth)acryloxypropyltriethoxysilane; preferably (meth)acryloxypropyltrimethoxysilane.

[0045] The second aspect of the present invention provides a method for preparing the acrylate emulsion for the tile back adhesive, including the following steps:

[0046] According to the ratio of the foregoing components, a pre-emulsion A containing components a), b), c), d), e), and f) of the core layer polymer is prepared.

[0047] A pre-emulsion B containing components a), b), c), e), and f) of the shell layer polymer is prepared.

[0048] A base liquid C containing a first emulsifier, component d), and an inhibitor is prepared, and an initiator solution D is prepared.

[0049] The raw materials containing the pre-emulsion A, pre-emulsion B, base liquid C, and initiator solution D are subjected to core-shell emulsion polymerization reaction. Preferably, it includes the following steps:

[0050] The core layer pre-emulsion A and the core layer initiator solution D are added to the base liquid C to obtain a core layer reaction product; the shell layer pre-emulsion B and the shell layer initiator solution D are continuously added to the core layer reaction product to obtain a core-shell structure polymer. After the reaction is completed, the pH value is adjusted at a high temperature, and an associative thickener is added to adjust the viscosity of the emulsion, and solid-liquid separation is performed to obtain the acrylate emulsion.

[0051] In the above steps of each stage of the present invention:

[0052] First, seeds and a core layer emulsion are prepared (that is, a part of the core layer pre-emulsion A and the initiator solution D are added to the base liquid), and then the remaining most of the pre-emulsion A and the initiator solution D are added dropwise synchronously. The seeds absorb monomers and continue to grow until the addition is completed; the controllable part lies in the composition of the pre-emulsion A. The structure of the core layer polymer can be controlled by adjusting the type of the pre-emulsion A and the content of each component.

[0053] After the core layer emulsion is prepared, the shell layer pre-emulsion B and the initiator solution D are synchronously added dropwise to prepare a polymer segment with a core-shell structure. Component e) and component f) are added to both the core layer pre-emulsion A and the shell layer pre-emulsion B. Component e) causes the polymer segments to be slightly crosslinked with each other to form a three-dimensional network structure, while component f) is like a "scissors" that appropriately cuts or blocks some of the crosslinking bonds to control the crosslinking degree between the segments. The combination of the two can ensure that the polymer has excellent initial tack, excellent adhesion strength, small loss of adhesion strength after water treatment, excellent adhesion of the clear lacquer film to water after soaking, and good water resistance.

[0054] Subsequently, high-temperature neutralization is carried out. At high temperatures, the polymer segments are active in movement, which is more conducive to the rapid penetration of the neutralizing agent through the shell layer polymer and at least partially neutralizing the hydrophilic functional groups in the core layer polymer. Through the hydration of the core layer polymer, the shell layer and the entire particle size are partially swollen, and at the same time, local hydrophilic substances extend to the surface of the polymer, and the hydrophobic segments of the shell layer also extend and are exposed, providing more binding sites for the subsequent interaction with the associative thickener. The hydrophilic substances are unevenly distributed between the core and the shell. The core layer is more hydrophilic, which is conducive to rapidly swelling and partially bursting the shell layer to expose it after neutralization; the shell layer is hydrophobic, and at the same time, a small amount of hydrophilic substances are added, which is conducive to the diffusion of the neutralizing agent into the core layer particles and swelling the core.

[0055] Addition of associative thickener: In the present invention, the associative thickener is added at a temperature higher than the discharge temperature. High temperature helps the thickener to be rapidly and uniformly dispersed in the emulsion. The hydrophobic end of the thickener associates with the hydrophobic end of the surface of the swollen polymer particles, playing a thickening role, and it is also the key to the stability of the thermal storage viscosity of the emulsion. When the emulsion is stored thermally, the movement of the polymer segments will intensify. Especially due to the special nature of this structure - the core layer is hydrophilic, the shell layer is hydrophobic, and the designed Tg values are both relatively low, and the thermal storage temperature is much higher than its glass transition temperature. The hydrophilic substances will inevitably flip outwards, occupying the associative sites of the thickener, resulting in a decrease in the emulsion viscosity or even the failure of the thickener. However, this structure can perfectly avoid this situation. Through the particle structure design, some hydrophilic substances are released to the surface of the polymer in advance after neutralization and swelling, and there are a small amount of hydrophilic substances in the shell layer itself, greatly reducing the polarity between the core layer and the shell layer; at the same time, both the core layer and the shell layer polymers are three-dimensional micro-crosslinked structures. The crosslinking of the core layer has a pulling and inhibitory effect on the outward migration of hydrophilic substances, and the crosslinking of the shell layer gives it a certain strength and will not be completely swollen and broken, but only broken at the weak points with incomplete coating, and the hydrophilic substances overflow. In this way, it can be ensured that the hydrophobic associative points on the surface of the polymer do not change during the thermal storage process, thereby ensuring the stability of the emulsion viscosity. By adjusting the dosage of the associative thickener in the present invention, the emulsion viscosity can be freely regulated to meet the requirements of different construction sites.

[0056] In a preferred embodiment, based on the total amount of the pre-emulsion, the seed part accounts for 2%-6% of the total pre-emulsion by mass, the core layer pre-emulsion A accounts for 25%-45% of the total pre-emulsion by mass, and the shell layer pre-emulsion B accounts for 55%-75% of the total pre-emulsion by mass.

[0057] In a preferred embodiment, based on the total amount of the initiator solution D, the seed part accounts for 40%-60% of the initiator solution D by mass, the core layer part accounts for 25%-45% of the initiator solution D by mass, and the shell layer part accounts for 55%-75% of the initiator solution D by mass.

[0058] In a preferred embodiment, based on the total amount of component a), the mass percentage of component a) in the seed part is 2%-6%, the mass percentage of component a) in the core layer part is 40%-45%, and the mass percentage of component a) in the shell layer part is 55%-60%.

[0059] In a preferred embodiment, based on the total amount of component b), the mass percentage of component a) in the seed part is 2%-6%, the mass percentage of component a) in the core layer part is 35%-40%, and the mass percentage of component a) in the shell layer part is 60%-65%.

[0060] In a preferred embodiment, based on the total amount of component c), the mass percentage of component a) in the seed part is 2%-6%, the mass percentage of component a) in the core layer part is 90%-95%, and the mass percentage of component a) in the shell layer part is 5%-10%.

[0061] In a preferred embodiment, based on the total amount of component d), the mass percentage of component a) in the seed part is 2%-6%, the mass percentage of component d) in the core layer part is 35%-45%, and the mass percentage of component d) in the bottom material liquid part is 55%-65%.

[0062] In a preferred embodiment, based on the total amount of component e), the mass percentage of component e) in the seed part is 2%-6%, the mass percentage of component e) in the core layer part is 65%-75%, and the mass percentage of component e) in the shell layer part is 25%-35%.

[0063] In a preferred embodiment, based on the total amount of component f), the mass percentage of component f) in the seed part is 2%-6%, the mass percentage of component f) in the core layer part is 45%-55%, and the mass percentage of component f) in the shell layer part is 45%-55%.

[0064] In a preferred embodiment, the emulsifier is an anionic emulsifier, and suitable anionic emulsifiers are selected from at least one of sodium dodecyl sulfate, sodium dodecylbenzenesulfonate, sodium dodecyl diphenyl ether sulfonate, and sodium alkyl sulfosuccinate, and more preferably sodium alkyl sulfosuccinate.

[0065] Preferably, the initiator is a water-soluble initiator, including but not limited to at least one of ammonium persulfate, sodium persulfate, and potassium persulfate, and more preferably ammonium persulfate.

[0066] Preferably, the inhibitor is one or more of TEMPO and hydroquinone.

[0067] In a preferred embodiment, the method for preparing the core layer pre-emulsion A includes: taking an anionic emulsifier, 0.2-0.8 parts by mass of the component d), and 20-50 parts by mass of deionized water, and sequentially adding thereto a part of the component a), component b), component c), component e), component f), and mixing well for standby.

[0068] In a preferred embodiment, the method for preparing the shell layer pre-emulsion B includes: taking an anionic emulsifier and 30-60 parts by mass of deionized water, and sequentially adding thereto a part of the component a), component b), component c), component e), component f), and mixing well for standby.

[0069] In a preferred embodiment, in the core-shell latex particles, the core layer and the shell layer respectively account for 25%-45% and 55%-75% of the total mass of the polymer.

[0070] In a preferred embodiment, the method for preparing the base stock solution C includes: adding the remaining anionic emulsifier, 0.1-1.0 parts by mass of the component d), and 0.001-0.01 parts by mass of the inhibitor and 40-100 parts by mass of deionized water into a reaction kettle, heating to 82-90 °C for standby;

[0071] In a preferred embodiment, the method for preparing the initiator solution D includes: mixing 0.2-0.8 parts by mass of the initiator and 7.0-40 parts by mass of deionized water for standby.

[0072] In a preferred embodiment, subjecting the raw materials including the pre-emulsion A, pre-emulsion B, base stock solution C, and initiator solution D to a radical emulsion polymerization reaction includes the following steps:

[0073] At 82-90 °C, add 2%-6% by mass of the core layer pre-emulsion A and 40%-60% by mass of the initiator solution D to the base stock solution C at one time. After reacting for 5-10 min, start to simultaneously dropwise add the remaining core layer pre-emulsion A and initiator solution D. When the core layer pre-emulsion A is completely dropped, stop dropping, keep warm for 10-30 min, and then simultaneously dropwise add the shell layer pre-emulsion B and the remaining initiator solution D, and ensure that during the dropping process, the dropping time of the initiator is longer than the total dropping time of the core layer pre-emulsion A and the shell layer pre-emulsion B; after the dropping is completed, keep warm for 15-45 min, and cool down to 70-75 °C;

[0074] Add the post-treatment agent dropwise to the reaction kettle, and keep the temperature for 15 - 30 min after dropping is completed.

[0075] Add the neutralizing agent dropwise to the reaction kettle, adjust the pH value to 7.0 - 9.0, keep the temperature for 45 - 60 min after dropping is completed, and then cool down to 45 - 55 °C.

[0076] Quickly add the associative thickener to the reaction kettle, mix well and keep the temperature for 25 - 45 min, then turn off the heating. Then add the defoaming agent and bactericide to it, and filter to obtain the acrylate emulsion.

[0077] Specifically, the post-treatment agent includes but is not limited to at least one of tert-butyl hydroperoxide (T-BHP), tert-amyl hydroperoxide (T-AHP), sodium bisulfite, sodium dithionite, isascorbic acid, etc. Preferably, it is tert-butyl hydroperoxide and / or isascorbic acid, and more preferably tert-butyl hydroperoxide and isascorbic acid with a mass ratio of 2:1.

[0078] In this article, the preparation processes of the core layer pre-emulsion A, the shell layer pre-emulsion B, the bottom material liquid C, and the initiator solution D are not in a specific order. Among them, the core layer pre-emulsion A and the shell layer pre-emulsion B include mixtures of various monomers and are the main bodies participating in the polymerization reaction; the bottom material liquid C mainly includes process water, a very small amount of inhibitor, part of the emulsifier, and part of the co-stabilizer. This part of the emulsifier mainly controls the particle size of the seed emulsion to obtain the emulsion with the final target particle size. The inhibitor is to prevent some monomers from being prematurely initiated, ensuring a uniform particle size distribution of the emulsion and good batch stability; part of the co-stabilizer prevents the hydrophilicity of the mixed monomers in the core layer pre-emulsion from being too strong, which is prone to self-polymerization and slag formation, ensuring the stable progress of the polymerization reaction, realizing the external circulation process, saving the polymerization reaction time. The initiator in the initiator solution D decomposes when heated to generate free radicals, inducing the monomers to carry out free radical polymerization.

[0079] The third aspect of the present invention provides the application of the acrylate emulsion described above or the acrylate emulsion prepared by the preparation method described above in the tile back glue.

[0080] Compared with the prior art, the present invention has the following advantages:

[0081] In the polymerization process of the raw materials containing components a), b), c), and d) of the acrylate emulsion of the present invention, a component e) with a special structure is added as a chain transfer agent and a component f) as a cross-linking agent. This cross-linking agent has sufficient cross-linking points, enabling the polymer to form a cross-linked three-dimensional network structure. This chain transfer agent can effectively control the cross-linking density, can appropriately block the cross-linking at some positions, thereby providing the best degree of branching and cross-linking, ensuring that the polymer has excellent initial tack, excellent bonding strength, small loss of bonding strength after water treatment, excellent adhesion of the clear paint film after soaking in water, and good water resistance.

[0082] The acrylate emulsion of the present invention uses a special structural component e) as a chain transfer agent, which has excellent chain transfer activity. It can obtain a copolymer with a narrow distribution while reducing the dosage. Moreover, the raw materials for synthesizing component e) are very easy to prepare with inexpensive raw materials. At the same time, component e) has no odor or has a faint odor, and no special preventive measures are required during use.

[0083] The acrylate emulsion of the present invention is divided into core-shell parts through molecular structure design. By adding a large amount of functional monomers containing carboxylic acids, a small amount of chain transfer agents and crosslinking monomers to the core layer, a hydrophilic micro-crosslinked polymer core is formed; a very small amount of functional monomers containing carboxylic acids, a small amount of chain transfer agents and crosslinking monomers are added to the shell layer to form a hydrophobic micro-crosslinked polymer shell. And an interpenetrating network structure is formed between the core and the shell, optimizing the tightness between the polymers and effectively connecting the core and shell parts. After high-temperature neutralization, the polymer chain segments are active at high temperature, which is more conducive to the neutralizing agent quickly penetrating through the shell layer polymer and at least partially neutralizing the hydrophilic functional groups in the core layer polymer. Through the hydration of the core layer polymer, the shell layer and the entire particle size are partially swollen. At the same time, local hydrophilic substances extend to the surface of the polymer, and the hydrophobic chain segments of the shell layer also extend and are exposed, providing more binding sites for subsequent interaction with associative thickeners. The hydrophilic substances are unevenly distributed between the core and the shell, and the core layer is more hydrophilic, which is conducive to quickly swelling and partially bursting the shell layer after neutralization and exposing it; the shell layer is hydrophobic, and at the same time a small amount of hydrophilic substances are added, which is conducive to the diffusion of the neutralizing agent into the core layer particles, swelling the core, and finally realizing high-efficiency thickening of the emulsion, and the viscosity of the emulsion during thermal storage is stable.

[0084] For the acrylate emulsion of the present invention, an associative thickener is added under temperature conditions higher than normal temperature. High temperature helps the thickener to be quickly and uniformly dispersed in the emulsion. The hydrophobic end of the thickener associates with the hydrophobic end on the surface of the swollen polymer particles, playing a thickening role, which is also the key to the stability of the viscosity of the emulsion during thermal storage. When the emulsion is stored under heat, the movement of the polymer chain segments will intensify. Especially due to the particularity of this structure - the core layer is hydrophilic, the shell layer is hydrophobic, and the designed Tg values are relatively low. The thermal storage temperature is much higher than its glass transition temperature, and the hydrophilic substances will inevitably flip outwards, occupying the associative sites of the thickener, resulting in a decrease in the emulsion viscosity or even the failure of the thickener. However, this structure can perfectly avoid this situation. Through particle structure design, some hydrophilic substances are released to the polymer surface in advance after neutralization and swelling, and there are a small amount of hydrophilic substances in the shell layer itself, greatly reducing the polarity between the core layer and the shell layer. At the same time, both the core layer and the shell layer polymers are three-dimensional micro-crosslinked structures. The crosslinking of the core layer has a pulling and inhibitory effect on the outward migration of hydrophilic substances, and the crosslinking of the shell layer gives it a certain strength and will not be completely burst, but only damaged at the weak points where the coating is incomplete, and the hydrophilic substances overflow. In this way, it can be ensured that the hydrophobic associative points on the polymer surface do not change during the thermal storage process, thereby ensuring the viscosity stability of the emulsion. By adjusting the dosage of the thickener, the present invention can freely control the viscosity of the emulsion to meet the requirements of different construction sites.

[0085] For the acrylate emulsion of the present invention, by controlling the type, ratio and dosage of component c) monoethylenically unsaturated carboxylic acid in the core layer and shell layer polymers, while maintaining the stability of the emulsion itself, the emulsion is given strong rigidity and good cohesive energy is obtained. At the same time, after the carboxylic acid contained in component c) carboxylic acid is neutralized by a neutralizing agent, a large amount of carboxylic acid in the core layer unfolds, causing partial swelling of the shell layer and the entire polymer particles. A small amount of carboxylic acid in the shell layer also unfolds, playing a synergistic stretching role, and the hydrophobic chain segments in the shell layer are more effectively stretched and exposed, providing more binding sites for subsequent interaction with the associative thickener, ensuring efficient thickening response and stable emulsion thermal storage stability.

[0086] For the acrylate emulsion of the present invention, component d) monoethylenically unsaturated sulfonic acid and its salts are added during the polymerization process, which can greatly improve the stability of the emulsion polymerization, enable it to have an external circulation process, greatly shorten the production time, and reduce the processing cost of the acrylate emulsion.

[0087] For the acrylate emulsion of the present invention, component f) monomers with monoethylenically unsaturated double bonds and hydrolyzable Si-organic bonds are added during the polymerization process, making the polymer molecular chains in a micro-crosslinked state, enhancing the cohesion between the polymer chains, improving the bonding strength before and after treatment without losing the initial tack, and greatly improving the utilization rate of the crosslinking monomers.

[0088] For the acrylate emulsion of the present invention, after the polymerization is completed, high-temperature neutralization is adopted. At high temperature, the polymer chain segments are active, which is more conducive to the rapid penetration of the neutralizing agent through the shell polymer and at least partially neutralize the hydrophilic functional groups in the core polymer. Through the hydration of the core polymer, the shell and the whole particle size are partially swollen. At the same time, the local hydrophilic substances extend to the surface of the polymer, and the hydrophobic segments of the shell also extend and are exposed, providing more binding sites for the subsequent interaction with the associative thickener.

[0089] For the acrylate emulsion of the present invention, after the high-temperature neutralization and heat preservation are completed, the associative thickener is added near the heat storage temperature. High temperature helps the thickener to be rapidly and uniformly dispersed in the emulsion. The hydrophobic end of the thickener associates with the hydrophobic end of the swollen polymer particle surface, playing a thickening role, which is also the key to the stability of the emulsion heat storage viscosity. When the emulsion is stored thermally, the movement of the polymer chain segments will intensify. Especially due to the special structure of this emulsion - the core layer is hydrophilic, the shell layer is hydrophobic, and the designed Tg values are both relatively low. The heat storage temperature is much higher than its glass transition temperature, and the hydrophilic substances will inevitably flip outwards, occupying the associative sites of the thickener, resulting in a decrease in the emulsion viscosity or even the failure of the thickener. However, this structure can perfectly avoid this situation. Through the particle structure design, some hydrophilic substances are released to the polymer surface in advance after neutralization and swelling, and there are a small amount of hydrophilic substances in the shell layer itself, greatly reducing the polarity between the core layer and the shell layer. At the same time, both the core layer and the shell layer polymers are three-dimensional micro-crosslinked structures. The crosslinking of the core layer has a pulling and inhibiting effect on the outward migration of hydrophilic substances, and the crosslinking of the shell layer gives it a certain strength and will not be completely broken, but only breaks at the weak points with incomplete coating, and the hydrophilic substances overflow. In this way, it can be ensured that the hydrophobic associative points on the polymer surface do not change during the heat storage process, thereby ensuring the viscosity stability of the emulsion. By adjusting the dosage of the thickener, the viscosity of the emulsion can be freely regulated to meet the requirements of different construction sites.

[0090] For the acrylate emulsion of the present invention, the pre-emulsification semi-continuous dropping process is adopted, which can effectively improve the polymerization stability and enable the chemical reaction to proceed under relatively mild conditions.

[0091] Other features and advantages of the present invention will be described in detail through subsequent specific embodiments. Specific Embodiments

[0092] The following combines examples to further illustrate the present application. However, the present application is not limited to the listed examples, and should also include equivalent improvements and deformations of the technical solutions defined in the appended claims of the present application.

[0093] The endpoints and any values in the ranges disclosed herein are not limited to the exact ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, between the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values, they can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed herein.

[0094] For certain specific steps involved in the experimental methods used in the following examples, unless otherwise specified, they are all conventional operations.

[0095] The materials, reagents, etc. used in the following examples, unless otherwise specified, can be obtained from commercial sources.

[0096] The "%" involved in the following examples, unless otherwise specified, all refer to mass percentage.

[0097] Ethyl 2,4-bis(ethoxycarbonyl)-2-methyl-4-pentenoate (special chain transfer agent) is a product of Aladdin;

[0098] Ethyl 2,4-bis(ethoxycarbonyl)-2-ethyl-4-pentenoate (special chain transfer agent) is a product of Aladdin;

[0099] Ethyl 2-benzyl-2,4-bis(ethoxycarbonyl)-4-pentenoate (special chain transfer agent) is a product of Aladdin;

[0100] Ethyl 2-ethoxycarbonyl-2,3-dimethyl-4-(tert-butoxycarbonyl)-4-pentenoate (special structure chain transfer agent) is a product of Aladdin;

[0101] 3-Methacryloxypropyltriethoxysilane (A-174) is a product of Nanjing Chenggong Organosilicon Materials Co., Ltd.;

[0102] Dodecyl mercaptan (ordinary chain transfer agent) is a product of Aladdin;

[0103] DES-30 (sodium alkyl sulfosuccinate) is a product of Solvay Investment Co., Ltd.;

[0104] SSS (sodium vinylbenzenesulfonate) is a product of Shandong Starlink Biotechnology Co., Ltd.;

[0105] COPS-1 (sodium 2-acrylamido-2-methylpropanesulfonate) is a product of Solvay Investment Co., Ltd.;

[0106] The inhibitor TEMPO is a product of Aladdin;

[0107] The defoamer A10 is a product of BASF Chemical Co., Ltd.;

[0108] The fungicides LX-150 and KORDEK are products of Dow Chemical Company.

[0109] Example 1

[0110] Weigh each material according to the following mass:

[0111] Core layer: 2 g (a) of methyl methacrylate, 3 g (a) of styrene, 17 g (b) of n-butyl acrylate, 34 g (b) of isooctyl acrylate, 1.25 g (c) of acrylic acid, 1.25 g (c) of methacrylic acid, 0.1 g (d) of sodium vinylbenzenesulfonate, 0.1 g (e) of ethyl 2,4-bis(ethoxycarbonyl)-2-methyl-4-pentenoate, 0.05 g (f) of A-174, 0.8 g (emulsifier) of DES-30, and deionized water;

[0112] Shell layer: 10 g (a) of styrene, 90 g (b) of n-butyl acrylate, 0.2 g (c) of methacrylic acid, 0.05 g (e) of ethyl 2,4-bis(ethoxycarbonyl)-2-methyl-4-pentenoate, 0.05 g (f) of A-174, 0.4 g (emulsifier) of DES-30, and deionized water;

[0113] Others: 0.2 g (initiator) of ammonium persulfate, 0.1 g (post-treatment agent) of tert-butyl hydroperoxide, 0.05 g (post-treatment agent) of isascorbic acid, and appropriate amounts of ethanolamine (pH regulator), associative thickener (to adjust the viscosity of the emulsion), and deionized water.

[0114] 1) Prepare the core layer pre-emulsion A: At normal temperature and pressure, add 0.8 g of DES-30, 0.1 g of sodium vinylbenzenesulfonate, and 20 g of deionized water to a pre-emulsion tank equipped with a monomer metering tank and a stirrer. After fully stirring and dissolving, sequentially add 2 g of methyl methacrylate, 3 g of styrene, 17 g of n-butyl acrylate, 34 g of isooctyl acrylate, 1.25 g of acrylic acid, 1.25 g of methacrylic acid, 0.1 g of ethyl 2,4-bis(ethoxycarbonyl)-2-methyl-4-pentenoate, and 0.05 g of A-174. After fully stirring and mixing evenly, set aside for later use;

[0115] 2) Prepare the shell layer pre-emulsion B: At normal temperature and pressure, add 0.4 g of DES-30 and 20 g of deionized water to a pre-emulsion tank equipped with a monomer metering tank and a stirrer. After fully stirring and dissolving, sequentially add 10 g of styrene, 90 g of n-butyl acrylate, 0.2 g of methacrylic acid, 0.05 g of ethyl 2,4-bis(ethoxycarbonyl)-2-methyl-4-pentenoate, and 0.05 g of A-174. After fully stirring and mixing evenly, set aside for later use;

[0116] 3) Preparation of bottom layer liquid C (bottom liquid of the kettle): Add 0.05 g of DES-30, 0.375 g of COPS-1, 0.005 g of TEMPO and 40 g of deionized water into a polymerization kettle equipped with a stirrer, a condenser, a constant flow pump feeding device and a constant flow dropping metering device, stir well to dissolve, and heat up to 82 °C inside the polymerization kettle;

[0117] 4) Preparation of initiator solution D: Under normal temperature and pressure, add 0.2 g of ammonium persulfate and 18 g of deionized water into an initiator tank equipped with a stirrer and a constant flow dropping device, stir until completely dissolved and set aside;

[0118] 5) When the temperature inside the reaction kettle reaches 82 °C, add successively into the reaction kettle 6% of the total amount of the core layer pre-emulsion A and 50% of the initiator solution D by mass percentage, react for 5 min under stirring, and drop the remaining core layer pre-emulsion A and initiator solution D into the reaction kettle through the constant flow pump feeding device. Stop dropping when the core layer pre-emulsion A is completely dropped, keep warm for 10 min, then synchronously drop the shell layer pre-emulsion B and the remaining initiator solution D, and ensure that during the dropping process, the dropping time of the initiator is longer than the total dropping time of the core layer pre-emulsion A and the shell layer pre-emulsion B. After the dropping is completed, keep warm for 15 min and then cool down to 70 °C;

[0119] 6) Drop into the reaction kettle the post-treatment agent, namely an aqueous solution of 0.1 g of tert-butyl hydroperoxide and an aqueous solution of 0.05 g of isoascorbic acid, and keep warm for 20 min after dropping;

[0120] 7) Drop into the reaction kettle the neutralizing agent to adjust the pH value to 7.5, keep warm for 50 min after dropping and then cool down to 45 °C;

[0121] 8) Add the associative thickener into the reaction kettle at one time, mix well and keep warm for 35 min, then turn off the heating, add 0.06 g of defoamer and 0.8 g of bactericide, and filter to obtain the acrylate emulsion.

[0122] Example 2

[0123] Weigh each material according to the following mass:

[0124] Core layer: 2 g of methyl methacrylate (a), 6 g of styrene (a), 20 g of n-butyl acrylate (b), 40 g of isooctyl acrylate (b), 2.5 g of acrylic acid (c), 2.5 g of methacrylic acid (c), 0.5 g of sodium vinylbenzenesulfonate (d), 0.3 g of ethyl 2,4-bis(ethoxycarbonyl)-2-methyl-4-pentenoate (e), 0.1 g of A-174 (f), 1.2 g of DES-30 (emulsifier) and deionized water;

[0125] Shell layer: 14 g of styrene (a), 105 g of n-butyl acrylate (b), 0.5 g of methacrylic acid (c), 0.15 g of ethyl 2,4-bis(ethoxycarbonyl)-2-methyl-4-pentenoate (e), 0.1 g of A-174 (f), 0.6 g of DES-30 (emulsifier) and deionized water;

[0126] Others: 0.5 g of ammonium persulfate (initiator), 0.5 g of tert-butyl hydroperoxide (post-treatment agent), 0.25 g of isoascorbic acid (post-treatment agent), and appropriate amounts of ethanolamine (pH regulator), associative thickener (to adjust the emulsion viscosity) and deionized water.

[0127] 1) Preparation of core layer pre-emulsion A: At normal temperature and pressure, add 1.2 g of DES-30, 0.5 g of sodium vinylbenzenesulfonate and 35 g of deionized water to a pre-emulsion tank equipped with a monomer metering tank and a stirrer. After stirring and dissolving thoroughly, add 2 g of methyl methacrylate, 6 g of styrene, 20 g of n-butyl acrylate, 40 g of isooctyl acrylate, 2.5 g of acrylic acid, 2.5 g of methacrylic acid, 0.3 g of ethyl 2,4-bis(ethoxycarbonyl)-2-methyl-4-pentenoate, 0.1 g of A-174 in sequence. After stirring and mixing thoroughly, set aside for use;

[0128] 2) Preparation of shell layer pre-emulsion B: At normal temperature and pressure, add 0.6 g of DES-30 and 50 g of deionized water to a pre-emulsion tank equipped with a monomer metering tank and a stirrer. After stirring and dissolving thoroughly, add 14 g of styrene, 105 g of n-butyl acrylate, 0.5 g of methacrylic acid, 0.15 g of ethyl 2,4-bis(ethoxycarbonyl)-2-methyl-4-pentenoate, 0.1 g of A-174 in sequence. After stirring and mixing thoroughly, set aside for use;

[0129] 3) Preparation of bottom stock solution C (bottom solution of the kettle): Add 0.1 g of DES-30, 1.875 g of COPS-1, 0.007 g of TEMPO and 80 g of deionized water to a polymerization kettle equipped with a stirrer, a condenser, a constant flow pump feeding device and a constant flow dropping metering device. Stir and dissolve thoroughly, and heat up to the temperature in the polymerization kettle reaching 84 °C;

[0130] 4) Preparation of initiator solution D: At normal temperature and pressure, add 0.5 g of ammonium persulfate and 31 g of deionized water to an initiator tank equipped with a stirrer and a constant flow dropping device. Stir until completely dissolved and set aside for use;

[0131] 5) When the temperature in the reaction kettle reaches 84 °C, successively add pre-emulsion A accounting for 2% of the total amount of the core-layer pre-emulsion and initiator solution D with a mass percentage of 40% into the reaction kettle, react for 10 min under stirring, and then drip the remaining core-layer pre-emulsion A and initiator solution D into the reaction kettle through a constant-flow pump feeding device. Stop dripping when the core-layer pre-emulsion A is completely dripped, keep warm for 25 min, and then synchronously drip shell-layer pre-emulsion B and the remaining initiator solution D, and ensure that during the dripping process, the dripping time of the initiator is longer than the total dripping time of the core-layer pre-emulsion A and the shell-layer pre-emulsion B. After the dripping is completed, keep warm for 45 min and then cool down to 72 °C;

[0132] 6) Drip the post-treatment agent into the reaction kettle, that is, an aqueous solution of 0.5 g of tert-butyl hydroperoxide and an aqueous solution of 0.25 g of isoascorbic acid, and keep warm for 25 min after dripping;

[0133] 7) Drip the neutralizing agent into the reaction kettle, adjust the pH value to 8.5, keep warm for 45 min after dripping and then cool down to 48 °C;

[0134] 8) Add the associative thickener into the reaction kettle at one time, mix well and keep warm for 40 min, then turn off the heating, add 0.082 g of defoamer and 1.0 g of bactericide into it, and obtain the acrylate emulsion after filtration.

[0135] Example 3

[0136] Weigh each material according to the following mass:

[0137] Core layer: 2 g of methyl methacrylate (a), 12 g of styrene (a), 23 g of n-butyl acrylate (b), 46 g of isooctyl acrylate (b), 3.25 g of acrylic acid (c), 3.25 g of methacrylic acid (c), 1.0 g of sodium vinylbenzenesulfonate (d), 0.45 g of ethyl 2,4-bis(ethoxycarbonyl)-2-methyl-4-pentenoate (e), 0.18 g of A-174 (f), 1.6 g of DES-30 (emulsifier) and deionized water;

[0138] Shell layer: 18 g of styrene (a), 110 g of n-butyl acrylate (b), 0.9 g of methacrylic acid (c), 0.225 g of ethyl 2,4-bis(ethoxycarbonyl)-2-methyl-4-pentenoate (e), 0.18 g of A-174 (f), 0.8 g of DES-30 (emulsifier) and deionized water;

[0139] Others: 0.8 g of ammonium persulfate (initiator), 1.0 g of tert-butyl hydroperoxide (post-treatment agent), 0.5 g of isoascorbic acid (post-treatment agent), and appropriate amount of ethanolamine (pH regulator), associative thickener (adjust the viscosity of the emulsion) and deionized water.

[0140] 1) Preparation of core layer pre-emulsion A: At normal temperature and pressure, add 1.6 g of DES-30, 1.0 g of sodium vinylbenzenesulfonate and 45 g of deionized water into a pre-emulsification tank equipped with a monomer metering tank and a stirrer. After fully stirring and dissolving, sequentially add 2 g of methyl methacrylate, 12 g of styrene, 23 g of n-butyl acrylate, 46 g of isooctyl acrylate, 3.25 g of acrylic acid, 3.25 g of methacrylic acid, 0.45 g of ethyl 2,4-bis(ethoxycarbonyl)-2-methyl-4-pentenoate, and 0.18 g of A-174. After fully stirring and mixing evenly, set aside for use;

[0141] 2) Preparation of shell layer pre-emulsion B: At normal temperature and pressure, add 0.8 g of DES-30 and 55 g of deionized water into a pre-emulsification tank equipped with a monomer metering tank and a stirrer. After fully stirring and dissolving, sequentially add 18 g of styrene, 110 g of n-butyl acrylate, 0.9 g of methacrylic acid, 0.225 g of ethyl 2,4-bis(ethoxycarbonyl)-2-methyl-4-pentenoate, and 0.18 g of A-174. After fully stirring and mixing evenly, set aside for use;

[0142] 3) Preparation of bottom material liquid C (bottom liquid of the kettle): Add 0.2 g of DES-30, 3.75 g of COPS-1, 0.01 g of TEMPO and 90 g of deionized water into a polymerization kettle equipped with a stirrer, a condenser, a constant flow pump feeding device and a constant flow dropping metering device. Stir fully to dissolve, and heat up to 90 °C inside the polymerization kettle;

[0143] 4) Preparation of initiator solution D: At normal temperature and pressure, add 0.8 g of ammonium persulfate and 30 g of deionized water into an initiator tank equipped with a stirrer and a constant flow dropping device. Stir until completely dissolved and set aside for use;

[0144] 5) When the temperature inside the reaction kettle reaches 90 °C, add pre-emulsion A accounting for 3% of the total amount of the core layer pre-emulsion and initiator solution D with a mass percentage of 60% into the reaction kettle in sequence. React for 8 min under stirring state. Drop the remaining core layer pre-emulsion A and initiator solution D into the reaction kettle through the constant flow pump feeding device. Stop dropping when the core layer pre-emulsion A is completely dropped. Keep warm for 20 min, and then synchronously drop the shell layer pre-emulsion B and the remaining initiator solution D, and ensure that during the dropping process, the dropping time of the initiator is longer than the total dropping time of the core layer pre-emulsion A and the shell layer pre-emulsion B. After the dropping is completed, keep warm for 30 min and then cool down to 75 °C;

[0145] 6) Drop the post-treatment agent into the reaction kettle, that is, an aqueous solution of 1.0 g of tert-butyl hydroperoxide and an aqueous solution of 0.5 g of isoascorbic acid. After dropping, keep warm for 30 min;

[0146] 7) Drop the neutralizing agent into the reaction kettle to adjust the pH value to 9.0. After dropping, keep warm for 55 min and then cool down to 55 °C;

[0147] 8) Add the associative thickener to the reaction kettle at one time. After mixing and keeping warm for 25 min, turn off the heating. Add 0.12 g of defoamer and 1.56 g of bactericide thereto, and filter to obtain the acrylate emulsion.

[0148] Example 4

[0149] Weigh each material according to the following mass:

[0150] Core layer: 1 g (a) of methyl methacrylate, 4 g (a) of styrene, 19 g (b) of n-butyl acrylate, 38 g (b) of isooctyl acrylate, 2.0 g (c) of acrylic acid, 2.0 g (c) of methacrylic acid, 0.2 g (d) of sodium vinylbenzenesulfonate, 0.16 g (e) of ethyl 2,4-bis(ethoxycarbonyl)-2-methyl-4-pentenoate, 0.07 g (f) of A-174, 1.0 g (emulsifier) of DES-30 and deionized water;

[0151] Shell layer: 12 g (a) of styrene, 95 g (b) of n-butyl acrylate, 0.4 g (c) of methacrylic acid, 0.08 g (e) of ethyl 2,4-bis(ethoxycarbonyl)-2-methyl-4-pentenoate, 0.07 g (f) of A-174, 0.5 g (emulsifier) of DES-30 and deionized water;

[0152] Others: 0.6 g (initiator) of ammonium persulfate, 0.3 g (post-treatment agent) of tert-butyl hydroperoxide, 0.15 g (post-treatment agent) of isoascorbic acid, and appropriate amount of ethanolamine (pH regulator), associative thickener (adjust the viscosity of the emulsion) and deionized water.

[0153] 1) Prepare the core layer pre-emulsion A: At normal temperature and pressure, add 1.0 g of DES-30, 0.2 g of sodium vinylbenzenesulfonate and 40 g of deionized water to the pre-emulsion tank equipped with a monomer metering tank and a stirrer. After fully stirring and dissolving, add 1 g of methyl methacrylate, 4 g of styrene, 19 g of n-butyl acrylate, 38 g of isooctyl acrylate, 2.0 g of acrylic acid, 2.0 g of methacrylic acid, 0.16 g of ethyl 2,4-bis(ethoxycarbonyl)-2-methyl-4-pentenoate, 0.07 g of A-174 in sequence. After fully stirring and mixing, set aside;

[0154] 2) Prepare the shell layer pre-emulsion B: At normal temperature and pressure, add 0.5 g of DES-30 and 55 g of deionized water to the pre-emulsion tank equipped with a monomer metering tank and a stirrer. After fully stirring and dissolving, add 12 g of styrene, 95 g of n-butyl acrylate, 0.4 g of methacrylic acid, 0.08 g of ethyl 2,4-bis(ethoxycarbonyl)-2-methyl-4-pentenoate, 0.07 g of A-174 in sequence. After fully stirring and mixing, set aside;

[0155] 3) Preparation of bottom layer liquid C (bottom liquid of the kettle): Add 0.15 g of DES-30, 0.75 g of COPS-1, 0.004 g of TEMPO and 85 g of deionized water into a polymerization kettle equipped with a stirrer, a condenser, a constant flow pump feeding device, and a constant flow dropping metering device, stir well to dissolve, and heat up to 86 °C inside the polymerization kettle;

[0156] 4) Preparation of initiator solution D: Under normal temperature and pressure, add 0.6 g of ammonium persulfate and 24 g of deionized water into an initiator tank equipped with a stirrer and a constant flow dropping device, stir until completely dissolved and set aside;

[0157] 5) When the temperature inside the reaction kettle reaches 86 °C, add pre-emulsion A accounting for 5% of the total amount of the core layer pre-emulsion and initiator solution D with a mass percentage of 33% into the reaction kettle in sequence, react for 7 min under stirring, and drip the remaining core layer pre-emulsion A and initiator solution D into the reaction kettle through the constant flow pump feeding device. When the dripping of the core layer pre-emulsion A is completed, stop dripping, keep warm for 15 min, then synchronously drip the shell layer pre-emulsion B and the remaining initiator solution D, and ensure that during the dripping process, the dripping time of the initiator is longer than the total dripping time of the core layer pre-emulsion A and the shell layer pre-emulsion B. After the dripping is completed, keep warm for 25 min and then cool down to 71 °C;

[0158] 6) Drip the post-treatment agent into the reaction kettle, that is, an aqueous solution of 0.3 g of tert-butyl hydroperoxide and an aqueous solution of 0.15 g of isoascorbic acid, and keep warm for 15 min after dripping;

[0159] 7) Drip the neutralizing agent into the reaction kettle to adjust the pH value to 8.0, keep warm for 52 min after dripping and then cool down to 46 °C;

[0160] 8) Add the associative thickener into the reaction kettle at one time, mix well and keep warm for 30 min, then turn off the heating, add 0.076 g of defoaming agent and 0.92 g of bactericide, and filter to obtain the acrylate emulsion.

[0161] Example 5

[0162] Weigh each material according to the following mass:

[0163] Core layer: 2 g of methyl methacrylate (a), 10 g of styrene (a), 22 g of n-butyl acrylate (b), 44 g of isooctyl acrylate (b), 3.0 g of acrylic acid (c), 3.0 g of methacrylic acid (c), 0.8 g of sodium vinylbenzenesulfonate (d), 0.4 g of ethyl 2,4-bis(ethoxycarbonyl)-2-methyl-4-pentenoate (e), 0.12 g of A-174 (f), 1.4 g of DES-30 (emulsifier) and deionized water;

[0164] Shell layer: 16 g of styrene (a), 115 g of n-butyl acrylate (b), 0.7 g of methacrylic acid (c), 0.2 g of ethyl 2,4-bis(ethoxycarbonyl)-2-methyl-4-pentenoate (e), 0.12 g of A-174 (f), 0.7 g of DES-30 (emulsifier), and deionized water;

[0165] Others: 0.7 g of ammonium persulfate (initiator), 0.7 g of tert-butyl hydroperoxide (post-treatment agent), 0.35 g of isoascorbic acid (post-treatment agent), and appropriate amounts of ethanolamine (pH regulator), associative thickener (to adjust the emulsion viscosity), and deionized water.

[0166] 1) Preparation of core layer pre-emulsion A: At normal temperature and pressure, add 1.4 g of DES-30, 0.8 g of sodium vinylbenzenesulfonate, and 45 g of deionized water to a pre-emulsion tank equipped with a monomer metering tank and a stirrer. After fully stirring and dissolving, sequentially add 2 g of methyl methacrylate, 10 g of styrene, 22 g of n-butyl acrylate, 44 g of isooctyl acrylate, 3.0 g of acrylic acid, 3.0 g of methacrylic acid, 0.4 g of ethyl 2,4-bis(ethoxycarbonyl)-2-methyl-4-pentenoate, and 0.12 g of A-174. After fully stirring and mixing evenly, set aside for later use;

[0167] 2) Preparation of shell layer pre-emulsion B: At normal temperature and pressure, add 0.7 g of DES-30 and 50 g of deionized water to a pre-emulsion tank equipped with a monomer metering tank and a stirrer. After fully stirring and dissolving, sequentially add 16 g of styrene, 115 g of n-butyl acrylate, 0.7 g of methacrylic acid, 0.2 g of ethyl 2,4-bis(ethoxycarbonyl)-2-methyl-4-pentenoate, and 0.12 g of A-174. After fully stirring and mixing evenly, set aside for later use;

[0168] 3) Preparation of bottom stock solution C (bottom solution of the kettle): Add 0.12 g of DES-30, 3.0 g of COPS-1, 0.008 g of TEMPO, and 85 g of deionized water to a polymerization kettle equipped with a stirrer, a condenser, a constant flow pump feeding device, and a constant flow dropping metering device. Stir fully to dissolve, and heat up to the temperature in the polymerization kettle reaching 85 °C;

[0169] 4) Preparation of initiator solution D: At normal temperature and pressure, add 0.7 g of ammonium persulfate and 27 g of deionized water to an initiator tank equipped with a stirrer and a constant flow dropping device. Stir until completely dissolved and set aside for later use;

[0170] 5) When the temperature in the reaction kettle reaches 85 °C, successively add pre-emulsion A accounting for 4% of the total amount of the core layer pre-emulsion and initiator solution D with a mass percentage of 50% into the reaction kettle, react for 6 min under stirring, and add the remaining core layer pre-emulsion A and initiator solution D dropwise into the reaction kettle through a constant-flow pump feeding device. Stop dropping when the core layer pre-emulsion A is completely dropped, keep warm for 20 min, then simultaneously dropwise add shell layer pre-emulsion B and the remaining initiator solution D, and ensure that during the dropping process, the dropping time of the initiator is longer than the total dropping time of the core layer pre-emulsion A and the shell layer pre-emulsion B. After the dropping is completed, keep warm for 35 min and then cool down to 73 °C;

[0171] 6) Dropwise add post-treatment agents into the reaction kettle, namely an aqueous solution of 0.7 g of tert-butyl hydroperoxide and an aqueous solution of 0.35 g of isoascorbic acid, and keep warm for 20 min after dropping;

[0172] 7) Dropwise add a neutralizing agent into the reaction kettle to adjust the pH value to 8.0, keep warm for 48 min after dropping and then cool down to 50 °C;

[0173] 8) Add an associative thickener into the reaction kettle at one time, mix well and keep warm for 45 min, then turn off the heating, add 0.102 g of defoamer and 1.22 g of bactericide into it, and obtain the acrylate emulsion after filtration.

[0174] Example 6

[0175] The difference from Example 3 is that: 0.45 g of chain transfer agent in the core layer (i.e., ethyl 2,4-bis(ethoxycarbonyl)-2-methyl-4-pentenoate) is replaced with ethyl 2,4-bis(ethoxycarbonyl)-2-ethyl-4-pentenoate in equal mass, and 0.225 g of chain transfer agent in the shell layer (i.e., ethyl 2,4-bis(ethoxycarbonyl)-2-methyl-4-pentenoate) is replaced with ethyl 2,4-bis(ethoxycarbonyl)-2-ethyl-4-pentenoate in equal mass. Other components and the preparation method of the emulsion are exactly the same as those in Example 3.

[0176] Example 7

[0177] The difference from Example 3 is that: 0.45 g of chain transfer agent in the core layer (i.e., ethyl 2,4-bis(ethoxycarbonyl)-2-methyl-4-pentenoate) is replaced with ethyl 2-benzyl-2,4-bis(ethoxycarbonyl)-4-pentenoate in equal mass, and 0.225 g of chain transfer agent in the shell layer (i.e., ethyl 2,4-bis(ethoxycarbonyl)-2-methyl-4-pentenoate) is replaced with ethyl 2-benzyl-2,4-bis(ethoxycarbonyl)-4-pentenoate in equal mass. Other components and the preparation method of the emulsion are exactly the same as those in Example 3.

[0178] Example 8

[0179] The difference from Example 3 is that: 0.45 g of the chain transfer agent in the core layer (i.e., ethyl 2,4-bis(ethoxycarbonyl)-2-methyl-4-pentenoate) is replaced with an equal mass of ethyl 2-ethoxycarbonyl-2,3-dimethyl-4-(tert-butoxycarbonyl)-4-pentenoate, and 0.225 g of the chain transfer agent in the shell layer (i.e., ethyl 2,4-bis(ethoxycarbonyl)-2-methyl-4-pentenoate) is replaced with an equal mass of ethyl 2-ethoxycarbonyl-2,3-dimethyl-4-(tert-butoxycarbonyl)-4-pentenoate. The other components and the method for preparing the emulsion are exactly the same as those in Example 3.

[0180] Comparative Example 1

[0181] The difference from Example 3 is that: 0.45 g of the conventional chain transfer agent (i.e., dodecyl mercaptan) is used to replace 0.45 g of the chain transfer agent (i.e., ethyl 2,4-bis(ethoxycarbonyl)-2-methyl-4-pentenoate) in the core layer, and 0.225 g of the conventional chain transfer agent (i.e., dodecyl mercaptan) is used to replace 0.225 g of the chain transfer agent (i.e., ethyl 2,4-bis(ethoxycarbonyl)-2-methyl-4-pentenoate) in the shell layer. The other components and the method for preparing the emulsion are exactly the same as those in Example 3.

[0182] Comparative Example 2

[0183] The difference from Example 3 is that: 0.36 g of A-174 is added to the core layer, while no A-174 is added to the shell layer. The other components and the method for preparing the emulsion are exactly the same as those in Example 3.

[0184] Comparative Example 3

[0185] The difference from Example 3 is that: no A-174 is added to the core layer, while 0.36 g of A-174 is added to the shell layer. The other components and the method for preparing the emulsion are exactly the same as those in Example 3.

[0186] Comparative Example 4

[0187] The difference from Example 3 is that: 3.25 g of acrylic acid and 4.15 g of methacrylic acid are added to the core layer, while no methacrylic acid is added to the shell layer. The other components and the method for preparing the emulsion are exactly the same as those in Example 3.

[0188] Comparative Example 5

[0189] The difference from Example 3 is that: 3.25 g of acrylic acid is added to the core layer and no methacrylic acid is added, while 4.15 g of methacrylic acid is added to the shell layer. The other components and the method for preparing the emulsion are exactly the same as those in Example 3.

[0190] Comparative Example 6

[0191] Weigh each raw material according to the following quality: 2 g of methyl methacrylate (a), 30 g of styrene (a), 133 g of n-butyl acrylate (b), 46 g of isooctyl acrylate (b), 3.25 g of acrylic acid (c), 4.15 g of methacrylic acid (c), 1.0 g of sodium vinylbenzenesulfonate, 0.675 g of ethyl 2,4-bis(ethoxycarbonyl)-2-methyl-4-pentenoate (e), 0.36 g of A-174 (f), 2.4 g of DES-30 (emulsifier), 0.8 g of ammonium persulfate (initiator), 1.0 g of tert-butyl hydroperoxide (post-treatment agent), 0.5 g of isoascorbic acid (post-treatment agent), and an appropriate amount of ethanolamine (pH regulator) and deionized water;

[0192] 1) Prepare pre-emulsion A: At normal temperature and pressure, add 2.4 g of DES-30, 1.0 g of sodium vinylbenzenesulfonate and 100 g of deionized water to a pre-emulsion tank equipped with a monomer metering tank and a stirrer. After fully stirring and dissolving, add 2 g of methyl methacrylate, 30 g of styrene, 133 g of n-butyl acrylate, 46 g of isooctyl acrylate, 3.25 g of acrylic acid, 4.15 g of methacrylic acid, 0.675 g of ethyl 2,4-bis(ethoxycarbonyl)-2-methyl-4-pentenoate, and 0.36 g of A-174 in sequence. After fully stirring and mixing evenly, set aside for later use;

[0193] 2) Prepare bottom liquid C (bottom liquid of the kettle): Add 0.2 g of DES-30, 3.75 g of COPS-1, 0.01 g of TEMPO and 90 g of deionized water to a polymerization kettle equipped with a stirrer, a condenser, a constant flow pump feeding device and a constant flow dropping metering device. Stir well to dissolve, and heat up to 90 °C inside the polymerization kettle;

[0194] 3) Prepare initiator solution D: At normal temperature and pressure, add 0.8 g of ammonium persulfate and 30 g of deionized water to an initiator tank equipped with a stirrer and a constant flow dropping device. Stir until completely dissolved and set aside for later use;

[0195] 4) When the temperature inside the reaction kettle reaches 90 °C, add 3% of pre-emulsion A based on the total amount of pre-emulsion A and 60% of initiator solution D by mass percentage to the reaction kettle in sequence. React for 8 min under stirring. Then, add the remaining pre-emulsion A and initiator solution D to the reaction kettle dropwise through the constant flow pump feeding device, ensuring that during the dropping process, the dropping time of the initiator is longer than the total dropping time of pre-emulsion A. After the dropping is completed, keep the temperature for 30 min and then cool down to 75 °C;

[0196] 5) Add post-treatment agents to the reaction kettle, namely an aqueous solution of 1.0 g of tert-butyl hydroperoxide and an aqueous solution of 0.5 g of isoascorbic acid. After dropping, keep the temperature for 30 min;

[0197] 6) Add a neutralizing agent dropwise to the reaction kettle, adjust the pH value to 9.0, and after dropping, keep warm for 55 min and then cool down to 55 °C;

[0198] 7) Add an associative thickener to the reaction kettle at one time, mix well and keep warm for 25 min, then turn off the heating, add 0.12 g of defoamer and 1.56 g of bactericide thereto, and obtain the acrylate emulsion after filtration.

[0199] Application example: Preparation and performance analysis of latex paint

[0200] Performance test method:

[0201] 1) Water resistance: Use a 100-μm wire bar to scrape the emulsion of the tile back adhesive provided in the examples and comparative examples on a glass plate, cure it in a constant temperature and humidity chamber for one day, soak it in water for one day, and test whether the clear paint film does not come off when rubbed by hand. The results are shown in Table 1.

[0202] 2) Initial tack: Use a 100-μm wire bar to scrape the emulsion of the tile back adhesive provided in the examples and comparative examples on a glass plate, and after curing it in a constant temperature and humidity chamber for one day, test the rolling distance of the rolling ball on the adhesive surface of the glass plate according to the rolling ball method of GBT4852. The results are shown in Table 1.

[0203] 3) Bonding strength: Brush the emulsion of the tile back adhesive provided in the examples and comparative examples on the back of a vitrified tile with a specification of 40*40 cm. After the emulsion is completely dry, press it on a small cement block, cure it in a constant temperature and humidity chamber for 7 days, and then test the bonding strength through a tensile machine. The results are shown in Table 1.

[0204] 4) Bonding strength after water treatment: Brush the emulsion of the tile back adhesive provided in the examples and comparative examples on the back of a vitrified tile with a specification of 40*40 cm. After the emulsion is completely dry, press it on a small cement block, cure it in a constant temperature and humidity chamber for 7 days, soak it in water for 7 days, and test the bonding strength after water treatment through a tensile machine. The results are shown in Table 1.

[0205] 5) Emulsion viscosity: At room temperature of 25 °C, use an RV rotational viscometer to measure the viscosity of the emulsion of the tile back adhesive provided in the examples and comparative examples at 63# / 60 rpm. The results are shown in Table 1.

[0206] 6) Emulsion viscosity after heat storage: Seal the emulsion of the tile back adhesive provided in the examples and comparative examples with insulating tape, put it in an oven at 50 °C for heat storage for 14 d, take it out after completion and let it cool down to room temperature of 25 °C, and use an RV rotational viscometer to measure the viscosity of the emulsion at 63# / 60 rpm. The results are shown in Table 1

[0207] The performance test results are shown in Table 1 below:

[0208] Table 1: Performance test results

[0209]

[0210] The pH values of the emulsions for tile back adhesives provided in the examples and comparative examples are 7.5 - 9.0, and the solid content is about 45%.

[0211] As can be seen from Table 1, the emulsions for tile back adhesives prepared according to Examples 1 - 8 of the present invention have high initial tack, excellent bonding strength, and still maintain high bonding strength after water treatment. The water resistance of the clear lacquer film is excellent, the viscosity of the emulsion can be freely adjusted, and the viscosity is stable after heat storage.

[0212] Compared with the reaction system of the examples of the present invention, a conventional chain transfer agent is used in the raw material components of Comparative Example 1, A - 174 is not added to the shell layer in the raw material components of Comparative Example 2, A - 174 is not added to the core layer in the raw material components of Comparative Example 3, methacrylic acid is not added to the shell layer in Comparative Example 4, a single acid is used in both the core layer and the shell layer in Comparative Example 5, and a homogeneous structure is used to prepare the emulsion for tile back adhesive in Comparative Example 6. As can be seen from Table 1, Comparative Examples 1 - 6 cannot balance the performance such as initial tack, bonding strength before and after treatment, viscosity and its stability of the emulsion, and water resistance of the lacquer film.

[0213] Obviously, the above - mentioned examples of the present invention are only examples for clearly illustrating the present invention, rather than limitations on the implementation modes of the present invention. For those of ordinary skill in the art, other different forms of changes or modifications can be made on the basis of the above description. It is impossible to list all the implementation modes here. All obvious changes or modifications derived from the technical solutions of the present invention are within the spirit scope covered by the present invention.

Claims

1. An acrylate emulsion for tile back glue, characterized in that, It is prepared by core-shell emulsion polymerization from a raw material containing the following components by mass parts or consisting of the following components by mass parts: 1) Core layer emulsion polymerization, including Component a): at least one monovinyl aromatic monomer and at least one C1-C4-alkyl ester of methacrylic acid and mixtures thereof, 5-15 parts; Component b): at least one C2-C 10 -alkyl acrylate, 50-70 parts; Component c): at least one α,β-monoethylenically unsaturated C3-C6-monocarboxylic acid, 2.5-7.5 parts; Component d): at least one monoethylenically unsaturated sulfonic acid and its salts, 0.1-1.0 part; Component e): at least one allyl compound chain transfer agent, 0.1-0.5 part; Component f): at least one monomer having a monoethylenically unsaturated double bond and a hydrolyzable Si-organic bond, 0.05-0.2 part; 2) Shell layer emulsion polymerization, including Component a): at least one monovinyl aromatic monomer and at least one C1-C4-alkyl ester of methacrylic acid and mixtures thereof, 10-20 parts; Component b): at least one C2-C 10 -alkyl acrylate, 90-120 parts; Component c): at least one α,β-monoethylenically unsaturated C3-C6-monocarboxylic acid, 0.2-1.0 part; Component e): at least one allyl compound chain transfer agent, 0.05-0.25 part; Component f): at least one monomer having a monoethylenically unsaturated double bond and a hydrolyzable Si-organic bond, 0.05-0.2 part; Wherein, in the core-shell latex particles, the core layer and the shell layer respectively account for 25%-50% and 50%-75% of the total mass of the polymer.

2. The acrylate emulsion for tile back glue according to claim 1, wherein, In the core layer emulsion polymerization, the component a) is 10-15 parts, the component b) is 55-70 parts; the component c) is 3.5-6.5 parts, the component d) is 0.2-0.8 part, the component e) is 0.1-0.3 part, and the component f) is 0.05-0.15 part; In the shell layer emulsion polymerization, the component a) is 15-20 parts, the component b) is 100-120 parts; the component c) is 0.2-0.8 part, the component e) is 0.1-0.2 part, and the component f) is 0.05-0.15 part; Wherein, in the core-shell latex particles, the core layer and the shell layer respectively account for 25%-45% and 55%-75% of the total mass of the polymer.

3. The acrylate emulsion for tile back glue according to claim 1 or 2, characterized in that, The monovinyl aromatic monomer of the component a) is selected from one or more of styrene, 2-methylstyrene, 4-methylstyrene, 2-(n-butyl)styrene, 4-(n-butyl)styrene and 4-(n-decyl)styrene, preferably styrene; and / or The C1-C4-alkyl ester of methacrylic acid of the component a) is selected from one or more of methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isobutyl methacrylate, n-butyl methacrylate, sec-butyl methacrylate, isobutyl methacrylate and tert-butyl methacrylate, preferably methyl methacrylate.

4. The acrylate emulsion for tile back glue according to claim 1 or 2, characterized in that, The C2-C acrylic acid of component b) 10 -alkyl esters are selected from one or more of ethyl acrylate, butyl acrylate, n-hexyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate, 2-propylheptyl acrylate, isooctyl acrylate, preferably one or two of butyl acrylate and isooctyl acrylate.

5. The acrylate emulsion for tile back adhesive according to claim 1 or 2, characterized in that, The α,β-monoethylenically unsaturated C3-C6-monocarboxylic acid of the component c) is selected from one or more of acrylic acid, methacrylic acid, crotonic acid, 2-ethylacrylic acid, 2-propylacrylic acid, 2-acryloyloxyacetic acid, 2-methacryloyloxyacetic acid, preferably one or two of acrylic acid and methacrylic acid.

6. The acrylate emulsion for tile back glue according to claim 1 or 2, characterized in that, The monoethylenically unsaturated sulfonic acids and their salts of component d) are selected from one or more of vinylsulfonic acid, allylsulfonic acid, 2-sulfoethyl acrylate, 2-sulfoethyl methacrylate, 3-sulfopropyl acrylate, 3-sulfopropyl methacrylate, 2-hydroxy-3-acryloyloxypropylsulfonic acid, 2-hydroxy-3-methacryloyloxypropylsulfonic acid, styrenesulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid and their salts, preferably one or more of styrenesulfonic acid and its salts, 2-acrylamido-2-methylpropanesulfonic acid and its salts, and more preferably the sodium salt.

7. The acrylate emulsion for tile back glue according to claim 1 or 2, characterized in that, The allyl compound chain transfer agent of component e) has the following structural formula: Wherein: X is selected from any one of hydrogen, CN, optionally substituted aryl, COOH, COOR and halogen; Y is selected from any one of hydrogen, C1-C6 alkyl, C1-C6 alkyl substituted by one or more substituents selected from hydroxyl, amino, C1-C6 alkoxy, C1-C6 alkoxycarbonyl, halogen, CN, optionally substituted aryl, C1-C6 alkenyl and C1-C6 alkynyl; R 1 and R 2 may be the same or different and are selected from C1-C 18 alkyl, C1-C alkyl substituted with substituents selected from hydroxy, C1-C6 acyloxy, C1-C6 alkoxy, amino, halogen, optionally substituted aryl, CN and NCO 12 any one of the alkyls; R 3 and R 4 may be the same or different and each is independently selected from the group consisting of hydrogen, C1-C4 alkyl, and halogen.

8. The acrylate emulsion for tile back adhesive according to claim 1 or 2, characterized in that, The monomer containing a monoethylenically unsaturated double bond and a hydrolyzable Si-organic bond of component f) is selected from one or more of vinyltrialkoxysilane, alkylvinyldialkoxysilane and (meth)acryloyloxyalkyltrialkoxysilane; Preferably, the monomer containing a monoethylenically unsaturated double bond and a hydrolyzable Si-organic bond of component f) is selected from one or more of vinyltrimethoxysilane, methylvinyldimethoxysilane, (meth)acryloyloxypropyl-trimethoxysilane and (meth)acryloyloxypropyltriethoxysilane; more preferably (meth)acryloyloxypropyl-trimethoxysilane.

9. The preparation method of the acrylate emulsion for tile back glue according to any one of claims 1-8, characterized in that A pre-emulsion A containing components a), b), c), d), e) and f) is prepared to obtain the core layer polymer; A pre-emulsion B containing components a), b), c), e) and f) is prepared to obtain the shell layer polymer; A bottom material liquid C containing a first emulsifier, component d) and an inhibitor is prepared and an initiator solution D is prepared; The raw materials containing the pre-emulsion A, pre-emulsion B, bottom material liquid C and initiator solution D are subjected to core-shell emulsion polymerization reaction. Preferably, the steps include: Adding the core layer pre-emulsion A and the core layer initiator solution D to the bottom material liquid C to obtain a core layer reaction product; continuing to add the shell layer pre-emulsion B and the shell layer initiator solution D to the core layer reaction product to obtain the core-shell structure polymer. After the reaction is completed, the pH value is adjusted at high temperature, and an associative thickener is added to adjust the viscosity of the emulsion, and the acrylate emulsion for tile back glue is obtained by solid-liquid separation.

10. The application of the acrylate emulsion for tile back glue according to any one of claims 1-8 or the acrylate emulsion prepared by the preparation method according to claim 9 in tile back glue.

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