Elastic emulsion and preparation method thereof as well as metal roof waterproof coating and preparation method thereof

Abstract

The invention discloses an elastic emulsion and a preparation method thereof, and a metal roof waterproof coating and a preparation method thereof, and relates to the technical field of high polymer materials. The elastic emulsion is prepared from the following components in parts by weight: 90 to 100 parts of deionized water, 88 to 88.5 parts of butyl acrylate, 3 to 5 parts of styrene, 4 to 5 parts of acrylonitrile, 1 to 2 parts of acrylic acid, 1 to 2 parts of acrylamide, 0.1 part of silane coupling agent, 0.7 to 1.5 parts of emulsifier, 0.3 to 0.5 part of initiator, 0.2 to 0.3 part of oxidant, 0.1 to 0.2 part of reducing agent, 0.4 to 0.8 part of pH regulator, 0.2 to 0.3 part of defoaming agent and 0.4 to 0.7 part of bactericide. According to the elastic emulsion, by adjusting the ratio of butyl acrylate to styrene to acrylonitrile to acrylic acid to acrylamide to the emulsifier, the theoretical glass transition temperature of the elastic emulsion can be controlled within the range from-40 DEG C to-45 DEG C, and therefore the elastic emulsion has excellent low-temperature flexibility and high drawing strength and elongation at break; the waterproof coating has good anti-cracking performance and has a waterproof effect for a long time.

Description

Technical Field

[0001] The invention relates to the technical field of polymer materials, and in particular to an elastic emulsion and a preparation method thereof, a metal roof waterproof coating and a preparation method thereof. Background Art

[0002] In the field of construction, metal roofs are widely used for their advantages such as durability and beautiful appearance. However, metal roofs face problems such as corrosion and leakage, so metal roof emulsions are needed. Existing metal roof emulsions are mainly composed of acrylic emulsions, and inorganic fillers are added to reduce costs. Among them, the performance of acrylic emulsions and the amount of inorganic fillers added will directly affect the mechanical properties and water absorption rate of the metal roof emulsion after film formation. In particular, stress shrinkage lines are prone to occur due to differences in drying speed during large-scale construction, affecting weather resistance and long-term waterproofing effects. Therefore, improving the low-temperature flexibility, adhesion, weather resistance, elongation and tensile strength of acrylic emulsions is an urgent problem to be solved in existing metal roof waterproofing.

[0003] It can be seen that the existing technology still needs to be improved and enhanced. Summary of the invention

[0004] In view of the above-mentioned deficiencies in the prior art, the object of the present invention is to provide an elastic emulsion and a preparation method thereof, a metal roof waterproof coating and a preparation method thereof, aiming to solve the defects of the metal roof waterproof coating in the prior art, such as poor low-temperature flexibility and insufficient waterproof effect.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] An elastic emulsion, wherein, by weight, the elastic emulsion comprises: 90-100 parts of deionized water, 88-88.5 parts of butyl acrylate, 3-5 parts of styrene, 4-5 parts of acrylonitrile, 1-2 parts of acrylic acid, 1-2 parts of acrylamide, 0.1 part of a silane coupling agent, 0.7-1.5 parts of an emulsifier, 0.3-0.5 parts of an initiator, 0.2-0.3 parts of an oxidant, 0.1-0.2 parts of a reducing agent, 0.4-0.8 parts of a pH regulator, 0.2-0.3 parts of a defoaming agent, and 0.4-0.7 parts of a bactericide.

[0007] In the elastic emulsion, the emulsifier includes an anionic emulsifier and a nonionic emulsifier, and the weight ratio of the anionic emulsifier to the nonionic emulsifier is (1-2):1.

[0008] In the elastic emulsion, the anionic emulsifier includes one or both of sodium dodecyl diphenyl ether disulfonate and ethoxylated alkyl sulfate sodium salt.

[0009] In the elastic emulsion, the nonionic emulsifier includes at least one of fatty alcohol polyoxyethylene ether and isomeric C13 fatty alcohol polyoxyethylene ether.

[0010] In the elastic emulsion, the silane coupling agent includes one or two of vinyl trimethoxy silane and glycidyl ether propyl trimethoxy silane.

[0011] A method for preparing an elastic emulsion, for preparing the elastic emulsion as described above, the method comprising the steps of:

[0012] A01. Add 30 to 35 parts of deionized water and 0.1 to 0.15 parts of emulsifier to the polymerization kettle, stir and mix, and heat to 86 to 88 ° C to obtain a bottom material liquid;

[0013] A02. Add the remaining emulsifier, 36 to 39 parts of deionized water, butyl acrylate, styrene, acrylonitrile, acrylic acid, acrylamide, and silane coupling agent into a pre-emulsification tank, stir and mix to obtain a pre-emulsion;

[0014] A03. Add 0.05 to 0.1 parts of initiator and 0.5 to 1.5 parts of deionized water to the initiator tank A, and stir until completely dissolved to obtain an initiator solution A;

[0015] A04. Add 0.2 to 0.4 parts of initiator and 5 to 7 parts of deionized water to the initiator tank B, and stir until completely dissolved to obtain an initiator solution B;

[0016] A05. Add 0.2-0.4 parts of oxidant and 2-3 parts of deionized water to the oxidant tank, and stir until completely dissolved to obtain an oxidant solution;

[0017] A06. Add 0.1 to 0.2 parts of reducing agent and 3 to 5 parts of deionized water to the reducing agent tank, and stir until completely dissolved to obtain a reducing agent solution;

[0018] A07. Add 5% by weight of the pre-emulsion to the polymerization reactor, then add the initiator solution A, stir and mix, and keep warm for 15 minutes; add the remaining pre-emulsion and all the initiator solution B at a constant flow rate, and after the addition is completed, keep warm at 88 to 90 ° C for a certain period of time;

[0019] A08. After the insulation is completed, the polymerization kettle is cooled to 75-80°C, and the oxidant solution and the reducing agent solution are added dropwise to the polymerization kettle;

[0020] A09. Cool the polymerization kettle to below 50°C, add a pH adjuster to adjust the pH to 7-9, then add a defoamer and the remaining deionized water, stir and mix, filter the material, and obtain an elastic emulsion.

[0021] A metal roof waterproof coating, which comprises, by weight: 38-50 parts of elastic emulsion, 7-12 parts of deionized water, 24-35 parts of heavy calcium, 7-11 parts of barium sulfate, 3-5 parts of titanium dioxide, 0.3-0.4 parts of defoaming agent, 0.5 parts of dispersant, 0.2-0.3 parts of bactericide, 0-0.6 parts of flash rust inhibitor, 0.1-0.3 parts of pH regulator, 1-1.3 parts of antifreeze agent, and 0.3-0.6 parts of thickener; the elastic emulsion is the elastic emulsion as claimed in any one of claims 1 to 6.

[0022] In the metal roof waterproof coating, the particle size of the heavy calcium is 700-800 meshes.

[0023] In the metal roof waterproof coating, the titanium dioxide is rutile titanium dioxide.

[0024] A method for preparing a metal waterproof coating, used for preparing the metal waterproof coating as described above, the method comprising the steps of:

[0025] B01. Add deionized water, defoamer, dispersant, pH adjuster, and antifreeze agent to a dispersion tank and stir at 600-800 rpm for 5-10 min.

[0026] B02. Add heavy calcium, barium sulfate and titanium dioxide to a dispersion tank and stir at a speed of 1000-1500 rpm for 20-30 min;

[0027] B03. Add filler to the dispersion tank, disperse evenly, add 0.2 parts of defoamer and bactericide, anti-flash rust agent, control the mixer speed to 600-1000 revolutions per minute, the mixing time is 20min;

[0028] B04. After adding the defoamer and dispersing for 20 min, the emulsion was added and the mixer speed was controlled to 600-1000 rpm, and the mixing time was 20 min;

[0029] B05. After adding the emulsion and dispersing for 20 min, a thickener was added to a suitable viscosity. The mixer speed was 600-1200 rpm, and the mixing time was 30 min;

[0030] B06. Filter the mixed paint to remove impurities and residues to obtain acrylic roof metal waterproof coating.

[0031] Beneficial effects:

[0032] The invention provides an elastic emulsion, which uses butyl acrylate as a soft monomer and styrene and acrylonitrile as hard monomers. The main skeleton of a waterproof coating emulsion can be constructed through the joint action of the soft and hard monomers; acrylic acid and acrylamide are used as functional monomers to give the elastic emulsion excellent toughness, mechanical stability, calcium ion stability and other properties; the elastic emulsion is modified by a silane coupling agent to improve the bonding strength and water resistance of the waterproof coating; the theoretical glass transition temperature of the elastic emulsion can be controlled at -40 to -45 DEG C by adjusting the ratio of butyl acrylate, styrene, acrylonitrile, acrylic acid, acrylamide and an emulsifier, thereby having excellent flexibility and anti-shock absorbing effect; after the waterproof coating containing the elastic emulsion is formed into a film, it has excellent low-temperature flexibility, high pulling strength and elongation at break; when used as a waterproof coating for a metal roof, it is not easy to crack along with the substrate when cracks appear on the substrate, so it can play a waterproof role for a long time. DETAILED DESCRIPTION

[0033] The present invention provides an elastic emulsion and a preparation method thereof, a metal roof waterproof coating and a preparation method thereof. In order to make the purpose, technical scheme and effect of the present invention clearer and more specific, the present invention is further described in detail with reference to the following examples. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0034] The invention provides an elastic emulsion, which comprises, by weight, 90-100 parts of deionized water, 88-88.5 parts of butyl acrylate, 3-5 parts of styrene, 4-5 parts of acrylonitrile, 1-2 parts of acrylic acid, 1-2 parts of acrylamide, 0.1 part of a silane coupling agent, 0.7-1.5 parts of an emulsifier, 0.3-0.5 parts of an initiator, 0.2-0.3 parts of an oxidant, 0.1-0.2 parts of a reducing agent, 0.4-0.8 parts of a pH regulator, 0.2-0.3 parts of a defoaming agent, and 0.4-0.7 parts of a bactericide.

[0035] In the elastic emulsion, butyl acrylate is used as a soft monomer, and styrene and acrylonitrile are used as hard monomers. Through the joint action of the soft and hard monomers, the main skeleton of the waterproof coating emulsion can be constructed, that is, the core part (emulsion seed) of the core-shell type acrylic emulsion is formed, so as to facilitate the subsequent further polymerization reaction. In addition, the butyl acrylate can make the emulsion have good flexibility. At the same time, the elastic emulsion uses acrylic acid and acrylamide as functional monomers to give the elastic emulsion excellent toughness, mechanical stability, calcium ion stability and other properties. After the emulsion is formed into a film, the adhesion of the paint film (waterproof coating) can be improved, and the stain resistance can also be improved. Furthermore, the elastic emulsion is modified by a silane coupling agent. The silane coupling agent The crosslinking agent can be grafted onto the core part (emulsion seed) of the emulsion, and under alkaline conditions, it can generate silanol bonds, which can improve the bonding strength and water resistance of the waterproof coating in subsequent film-forming use; most importantly, by adjusting the ratio of butyl acrylate, styrene, acrylonitrile, acrylic acid, acrylamide and emulsifier, the theoretical glass transition temperature of the elastic emulsion can be controlled at -40 to -45°C, thereby having excellent flexibility and anti-shock absorption effect. When the waterproof coating containing the elastic emulsion is formed into a film, it has excellent low-temperature flexibility, high tensile strength and elongation at break. When used as a metal roof waterproof coating, it is not easy to crack with the substrate when cracks appear in the substrate, so it can play a waterproof role for a long time.

[0036] In addition, the aforementioned elastic emulsion also reduces the branching and cross-linking of the polymer by strictly controlling the dosage of functional monomers, so that the waterproof coating is less affected by aging caused by changes in the substrate and natural environment, and has better adaptability to the environment. The compounded waterproof coating can be flexible on the substrate for a long time without drastic changes.

[0037] As a preferred solution, the emulsifier includes anionic emulsifier and nonionic emulsifier, wherein the nonionic emulsifier is an amphiphilic compound, but does not dissociate into an ionic state in water, has high stability, is not easily affected by the presence of strong electrolytes, and is not easily affected by acids and alkalis, can be mixed with other types of surfactants, and has good compatibility; after the anionic emulsifier is dissolved in water, its active part tends to dissociate into a negatively charged ion surfactant, which is characterized by having a large organic anion that can react with alkali to form a salt. By using anionic emulsifiers and nonionic emulsifiers together, a better emulsification effect can be achieved.

[0038] More preferably, when the weight ratio of the anionic emulsifier to the nonionic emulsifier is (1-2):1, the stability and emulsification performance of the emulsion are better, and the amount of emulsifier used is less, which can reduce the negative effects caused by the large amount of free emulsifier and avoid the deterioration of the storage stability of the emulsion.

[0039] Furthermore, the anionic emulsifier includes one or a combination of ethoxylated alkyl sulfate sodium salt and sodium dodecyl diphenyl oxide disulfonate. When it is a combination of two, they can be mixed in any proportion. Among them, the ethoxylated alkyl sulfate sodium salt has good emulsification performance, can disperse the core part of the emulsion in the water phase and keep it uniform and stable. The sodium dodecyl diphenyl oxide disulfonate is still suitable for emulsion polymerization at 80-120°C without losing surface activity.

[0040] Furthermore, the nonionic emulsifier includes one or a combination of fatty alcohol polyoxyethylene ether and isomeric C13 fatty alcohol polyoxyethylene ether. The two nonionic emulsifiers can be mixed in any proportion to form a stable emulsion between the water phase and the oil phase to achieve emulsification and dispersion effects. In addition, since fatty alcohol polyoxyethylene ether and isomeric C13 fatty alcohol polyoxyethylene ether do not contain sulfur, the elastic emulsion will not react with metal ions to cause discoloration.

[0041] Furthermore, the silane coupling agent includes one or two of vinyl trimethoxysilane and glycidyl ether propyl trimethoxysilane. The vinyl trimethoxysilane can copolymerize with acrylic monomers to make the coating have excellent water resistance, weather resistance and scrubability. The glycidyl ether propyl trimethoxysilane is an epoxy-containing coupling agent that can improve the bonding performance of the emulsion with inorganic materials (such as tiles and other building materials).

[0042] The initiator includes at least one of potassium persulfate and sodium persulfate; the reducing agent includes at least one of ascorbic acid and sodium sulfite; the oxidant is tert-butyl hydroperoxide. The oxidant and reducing agent are used to treat the residual monomers in the emulsion, improve the conversion efficiency of soft monomers, hard monomers and functional monomers, eliminate irritating odors, reduce the odor of the coating, and improve the health of the construction workers while being environmentally friendly.

[0043] The second aspect of the present invention also provides a method for preparing an elastic emulsion, the method comprising the steps of:

[0044] A01. Add 30 to 35 parts of deionized water and 0.1 to 0.15 parts of emulsifier to the polymerization kettle, stir and mix, and heat to 86 to 88 ° C to obtain a bottom liquid;

[0045] A02. Add the remaining emulsifier, 36 to 39 parts of deionized water, butyl acrylate, styrene, acrylonitrile, acrylic acid, acrylamide, and silane coupling agent into a pre-emulsification tank, stir and mix to obtain a pre-emulsion;

[0046] A03. Add 0.05 to 0.1 parts of initiator and 0.5 to 1.5 parts of deionized water to the initiator tank A, and stir until completely dissolved to obtain an initiator solution A;

[0047] A04. Add 0.2 to 0.4 parts of initiator and 5 to 7 parts of deionized water to the initiator tank B, and stir until completely dissolved to obtain an initiator solution B;

[0048] A05. Add 0.2-0.4 parts of oxidant and 2-3 parts of deionized water to the oxidant tank, and stir until completely dissolved to obtain an oxidant solution;

[0049] A06. Add 0.1 to 0.2 parts of reducing agent and 3 to 5 parts of deionized water to the reducing agent tank, and stir until completely dissolved to obtain a reducing agent solution;

[0050] A07. Add 5% by weight of the pre-emulsion to the polymerization reactor, then add the initiator solution A, stir and mix, and keep warm for 15 minutes; add the remaining pre-emulsion and all the initiator solution B at a constant flow rate, and after the addition is completed, keep warm at 88 to 90 ° C for a certain period of time;

[0051] A08. After the insulation is completed, the polymerization kettle is cooled to 75-80°C, and the oxidant solution and the reducing agent solution are added dropwise to the polymerization kettle;

[0052] A09. Cool the polymerization kettle to below 50°C, add a pH adjuster to adjust the pH to 7-9, then add a defoamer and the remaining deionized water, stir and mix, filter the material, and obtain an elastic emulsion.

[0053] The preparation method prepares a seed emulsion (pre-emulsion) first, and then further polymerizes the seed emulsion, so that the prepared elastic emulsion has a narrow particle size distribution, easy to control particle size and better stability. At the same time, by adding an oxidant or a reducing agent to treat the residual monomers during the preparation process, the conversion rate of the monomers can be increased, the irritating odor can be eliminated, and the odor of the waterproof coating emulsion and the waterproof coating can be reduced, which is environmentally friendly and improves the health of the constructors.

[0054] The elastic emulsion prepared by the present invention is formulated into a coating that belongs to a single-component water-based coating, and can be directly applied on a dry substrate without visible water by spraying, roller or brush. The coating is not easily aged by changes in the substrate and the natural environment, and has the characteristics of excellent low-temperature flexibility, adhesion, waterproofness, weather resistance, excellent tensile strength and elongation.

[0055] The third aspect of the present invention also provides a metal roof waterproof coating, which includes, by weight: 38 to 50 parts of elastic emulsion, 7 to 12 parts of deionized water, 24 to 35 parts of heavy calcium, 7 to 11 parts of barium sulfate, 3 to 5 parts of titanium dioxide, 0.3 to 0.4 parts of defoaming agent, 0.5 parts of dispersant, 0.2 to 0.3 parts of bactericide, 0 to 0.6 parts of anti-flash rust agent, 0.1 to 0.3 parts of pH regulator, 1 to 1.3 parts of antifreeze agent, and 0.3 to 0.6 parts of thickener.

[0056] In the waterproof coating, the aforementioned elastic emulsion is used as a matrix, which is an elastic emulsion polymerized with butyl acrylate, styrene, and acrylonitrile as main monomers. The theoretical glass transition temperature of the elastic emulsion is -40 to -45°C, which can make the waterproof coating have excellent low-temperature flexibility, adhesion, waterproofness, weather resistance, excellent elasticity and elongation emulsion, which can solve the problems of poor low-temperature flexibility and elasticity of the existing metal roof waterproof anti-corrosion coating, low elongation at break, easy cracking, peeling, and poor waterproof and anti-corrosion effect. At the same time, the waterproof emulsion uses heavy calcium, titanium dioxide and barium sulfate as fillers to improve the mechanical strength, adhesion, wear resistance, anti-aging and corrosion resistance of the coating, extend the life of the paint film, and at the same time improve the covering power of the coating, enhance the hardness and wear resistance of the coating, make the coating more durable, resist external friction and scratches, play a certain anti-sedimentation role, and make the pigments and other components in the coating more evenly distributed to maintain the stability of the coating. In addition, through the effects of defoamers, dispersants, bactericides and anti-rust agents, the coating has long-lasting dispersibility and anti-rust properties, and the viscosity of the coating system is quite stable.

[0057] In a preferred embodiment, the heavy calcium carbonate is 700-800 mesh heavy calcium carbonate, which can enhance the hardness and wear resistance of the coating, make the coating more durable, and can also play a certain anti-sedimentation role, allowing the pigments and other ingredients in the coating to be more evenly distributed, thereby maintaining the stability of the coating.

[0058] Furthermore, the titanium dioxide is rutile titanium dioxide. Due to its high refractive index, rutile titanium dioxide can achieve a good covering effect for the coating when added in a small amount, reducing the coating thickness while ensuring the uniformity of the appearance; the defoaming agent is a mineral oil defoaming agent; the anti-flash rust agent is composed of phosphates, phosphate esters, diethanolamine, etc.; the barium sulfate is ultrafine precipitated barium sulfate, which can improve the gloss of the coating, make the coating surface brighter and smoother, and can also enhance the hardness and wear resistance of the coating, making the coating more durable and resistant to external friction and scratches.

[0059] The fourth aspect of the present invention also provides a method for preparing a metal waterproof coating, comprising the following steps:

[0060] B01. Add deionized water, defoamer, dispersant, pH adjuster, and antifreeze agent to a dispersion tank and stir at 600-800 rpm for 5-10 min.

[0061] B02. Add heavy calcium, barium sulfate and titanium dioxide to a dispersion tank and stir at a speed of 1000-1500 rpm for 20-30 min;

[0062] B03. Add filler to the dispersion tank, disperse evenly, add 0.2 parts of defoamer and bactericide, anti-flash rust agent, control the mixer speed to 600-1000 revolutions per minute, the mixing time is 20min;

[0063] B04. After adding the defoamer and dispersing for 20 min, the emulsion was added and the mixer speed was controlled to 600-1000 rpm, and the mixing time was 20 min;

[0064] B05. After adding the emulsion and dispersing for 20 min, a thickener was added to a suitable viscosity. The mixer speed was 600-1200 rpm, and the mixing time was 30 min;

[0065] B06. Filter the mixed paint to remove impurities and residues to obtain acrylic roof metal waterproof coating.

[0066] The preparation method avoids the formation of small bubbles that affect the tensile strength and elongation of the coating by adjusting the adding sequence and the stirring speed.

[0067] To further illustrate the inventive concept of the present invention, the following examples are provided.

[0068] Example 1

[0069] An elastic emulsion, calculated by weight, includes the following components: 98 parts of deionized water, 88.5 parts of butyl acrylate, 3 parts of styrene, 5 parts of acrylonitrile, 1.7 parts of acrylic acid, 1.7 parts of acrylamide, 0.1 parts of glycidyl ether propyl trimethoxy silane, 0.9 parts of emulsifier, 0.4 parts of sodium persulfate, 0.3 parts of tert-butyl hydroperoxide, 0.2 parts of sodium bisulfite, 0.6 parts of sodium hydroxide, 0.2 parts of defoamer, and 0.6 parts of bactericide. The emulsifier is composed of 0.5 parts of ethoxylated alkyl sulfate sodium salt and 0.3 parts of fatty alcohol polyoxyethylene ether.

[0070] The preparation method of the elastic emulsion is:

[0071] A01. Add 31 parts of deionized water and 0.1 parts of emulsifier to a polymerization kettle equipped with a stirrer, a condenser and a constant flow pump feeding device to obtain a bottom feed liquid, and at the same time, the temperature in the kettle is raised to 86-88°C;

[0072] A02. Add the remaining emulsifier, 38 parts of deionized water, butyl acrylate, styrene, acrylonitrile, acrylic acid, acrylamide, and silane coupling agent to a pre-emulsification tank equipped with a monomer metering tank and a stirrer at room temperature and pressure, stir and mix to form a uniform pre-emulsion, and then continue stirring for 20 to 40 minutes for use;

[0073] A03. At room temperature and pressure, 0.1 parts of sodium persulfate and 1.5 parts of deionized water were added to an initiator tank with a stirrer and a constant flow dropping device, and stirred until completely dissolved to obtain an initiator solution A;

[0074] A04. At room temperature and pressure, 0.3 parts of sodium persulfate and 7 parts of deionized water were added to an initiator tank with a stirrer and a constant flow dropping device, and stirred until completely dissolved to obtain an initiator solution B;

[0075] A05. Add 0.3 parts of tert-butyl hydroperoxide and 3 parts of deionized water to an oxidant tank with a stirrer and a constant flow dosing device at room temperature and pressure, and stir until completely dissolved to obtain an oxidant solution;

[0076] A06. Add 0.2 parts of sodium bisulfite and 4.5 parts of deionized water to a reducing agent tank with a stirrer and a constant flow adding device at room temperature and pressure, and stir until completely dissolved to obtain a reducing agent solution;

[0077] A07. When the temperature in the polymerization kettle reaches 86°C, 5% by weight of the pre-emulsion is initially added to the polymerization kettle, and then the initiator solution A is added. After waiting for the temperature to rise, the timing is 15 minutes, and then the pre-emulsion and the initiator solution B are uniformly added to the polymerization kettle by a constant flow pump feeding device and a constant flow dripping metering device. The dripping time is controlled to be completed within 3.5 to 4 hours, and the temperature is kept at 88 to 90°C for 60 minutes;

[0078] A08. When the temperature in the polymerization reactor is lowered to 75-80°C, the oxidant solution and the reducing agent solution are added dropwise to the polymerization reactor at the same time. The addition time is controlled within 1 to 1.5 hours to treat the residual monomers.

[0079] A09. After the residual monomer treatment is completed, wait for the temperature in the polymerization kettle to drop below 50°C, add sodium hydroxide to adjust the pH to 7-9, then add the defoaming agent and the remaining deionized water, stir for 0.5-1 hour, filter the material, and obtain a one-component acrylic metal roof waterproof coating elastic emulsion.

[0080] Example 2

[0081] An elastic emulsion comprises the following components, calculated by weight: 90 parts of deionized water, 88.5 parts of butyl acrylate, 3 parts of styrene, 5 parts of acrylonitrile, 2 parts of acrylic acid, 1.5 parts of acrylamide, 0.1 part of vinyl trimethoxy silane, 0.7 part of emulsifier, 0.3 part of sodium persulfate, 0.3 part of tert-butyl hydroperoxide, 0.1 part of sodium bisulfite, 0.1 part of ascorbic acid, 0.8 part of sodium hydroxide, 0.3 part of defoamer and 0.4 part of bactericide; the emulsifier is composed of 0.4 part of ethoxylated alkyl sulfate sodium salt and 0.7 part of fatty alcohol polyoxyethylene ether.

[0082] Example 3

[0083] An elastic emulsion, calculated by weight, includes the following components: 100 parts of deionized water, 88 parts of butyl acrylate, 5 parts of styrene, 4 parts of acrylonitrile, 1 part of acrylic acid, 2 parts of acrylamide, 0.1 parts of vinyl trimethoxy silane, 1.5 parts of emulsifier, 0.5 parts of sodium persulfate, 0.2 parts of tert-butyl hydroperoxide, 0.1 parts of sodium bisulfite, 0.4 parts of sodium hydroxide, 0.2 parts of defoamer, 0.6 parts of bactericide. The emulsifier is composed of 0.7 parts of ethoxylated alkyl sulfate sodium salt and 0.8 parts of fatty alcohol polyoxyethylene ether.

[0084] It should be noted that the preparation methods of Example 2 and Example 3 are basically the same as that of Example 1, and the only difference is the different ratio of ingredients.

[0085] Comparative Example 1

[0086] An emulsion comprises the following components by weight: 98 parts of deionized water, 91.5 parts of butyl acrylate, 2 parts of styrene, 3 parts of acrylonitrile, 1.7 parts of acrylic acid, 1.7 parts of acrylamide, 0.8 parts of emulsifier, 0.1 parts of vinyltrimethoxysilane, 0.46 parts of sodium persulfate, 0.35 parts of tert-butyl hydroperoxide, 0.8 parts of ascorbic acid, 0.7 parts of sodium hydroxide, 0.1 parts of defoamer and 0.6 parts of bactericide.

[0087] Comparative Example 2

[0088] An emulsion comprises the following components, calculated by weight: 98 parts of deionized water, 58.27 parts of butyl acrylate, 15 parts of styrene, 5 parts of acrylonitrile, 1 part of acrylamide, 1.5 parts of acrylic acid, 0.1 part of vinyltrimethoxysilane, 1 part of emulsifier, 0.46 parts of potassium persulfate, 0.3 parts of tert-butyl hydroperoxide, 0.4 parts of sodium bisulfite, 0.7 parts of sodium hydroxide, 0.1 parts of defoamer and 0.6 parts of bactericide.

[0089] It should be noted that the preparation methods of the emulsions described in Comparative Examples 1 and 2 are substantially the same as those in Example 1, except that the ratios of the raw materials are different.

[0090] The elastic emulsions described in Examples 1-3 and the emulsions described in Comparative Examples 1 and 2 were used to prepare metal roof waterproof coatings to obtain the following examples and comparative examples.

[0091] Example 4

[0092] A metal roof waterproof coating comprises the following raw materials in parts by weight: 40 parts of the elastic emulsion described in Example 1, 12 parts of deionized water, 35 parts of heavy calcium, 7 parts of barium sulfate, 3 parts of titanium dioxide, 0.3 parts of defoaming agent, 0.5 parts of dispersant, 0.2 parts of bactericide, 0.2 parts of anti-flash rust agent, 0.2 parts of pH regulator, 1 part of antifreeze agent, and 0.6 parts of thickener.

[0093] The particle size of the heavy calcium is 700-800 mesh, the titanium dioxide is rutile titanium dioxide, the barium sulfate is ultrafine precipitated barium sulfate, the defoamer is a mineral oil defoamer, and the anti-flash rust agent consists of phosphate, phosphate ester, and diethanolamine.

[0094] A method for preparing the metal roof waterproof coating comprises the following steps:

[0095] B01. Add 11.7 parts of deionized water, 0.1 parts of defoamer, 0.5 parts of dispersant, 0.2 parts of PH regulator, 1 part of antifreeze agent to a dispersion tank with water circulation, control the mixer speed to 600-800 revolutions per minute, and the mixing time is 5-10min;

[0096] B02. After 5-10 minutes of dispersion, the dispersion tank is connected to the water circulation; 35 parts of heavy calcium, 7 parts of barium sulfate, and 3 parts of titanium dioxide are added, and the stirrer speed is controlled to 1000-1500 revolutions per minute, and the mixing time is 20-30 minutes; if it is difficult to disperse, 5-10 parts of the emulsion can be added to the dispersion tank for dispersion;

[0097] B03. After adding the filler and dispersing for 20-30 minutes, add 0.2 parts of defoamer, 0.2 parts of bactericide, and 0.2 parts of anti-flash rust agent, control the mixer speed to 600-1000 revolutions per minute, and the mixing time is 20 minutes; B04. After adding the defoamer and dispersing for 20 minutes, add the emulsion and control the mixer speed to 600-1000 revolutions per minute, and the mixing time is 20 minutes;

[0098] B05. After adding the emulsion and dispersing for 20 min, a thickener was added to a suitable viscosity. The mixer speed was 600-1200 rpm, and the mixing time was 30 min;

[0099] B06. Filter the mixed paint to remove impurities and residues to obtain acrylic roof metal waterproof coating.

[0100] Example 5

[0101] A metal roof waterproof coating comprises the following components in parts by weight: 38 parts of the elastic emulsion described in Example 2, 11 parts of deionized water, 35 parts of heavy calcium, 10 parts of barium sulfate, 3 parts of titanium dioxide, 0.3 parts of defoamer, 0.5 parts of dispersant, 0.2 parts of bactericide, 0.2 parts of anti-flash rust agent, 0.2 parts of pH regulator, 1 part of antifreeze agent, and 0.6 parts of thickener. The particle size of the heavy calcium is 700-800 mesh, the titanium dioxide is rutile titanium dioxide, the barium sulfate is ultrafine precipitated barium sulfate, the defoamer is a mineral oil defoamer, and the anti-flash rust agent is composed of phosphate, phosphate ester, and diethanolamine.

[0102] The preparation method of the metal roof waterproof coating of Example 5 is basically the same as that of Example 4, with only the raw material components being different.

[0103] Example 6

[0104] A metal roof waterproof coating comprises the following components in parts by weight: 50 parts of the elastic emulsion described in Example 3, 7 parts of deionized water, 24 parts of heavy calcium, 11 parts of barium sulfate, 5 parts of titanium dioxide, 0.4 parts of defoamer, 0.5 parts of dispersant, 0.3 parts of bactericide, 0.2 parts of anti-flash rust agent, 0.2 parts of pH regulator, 1.3 parts of antifreeze agent, and 0.3 parts of thickener. The particle size of the heavy calcium is 700-800 mesh, the titanium dioxide is rutile titanium dioxide, the barium sulfate is ultrafine precipitated barium sulfate, the defoamer is a mineral oil defoamer, and the anti-flash rust agent is composed of phosphate, phosphate ester, and diethanolamine.

[0105] The preparation method of the metal roof waterproof coating of Example 6 is basically the same as that of Example 4, with only the raw material components being different.

[0106] Comparative Example 3

[0107] A metal roof waterproof emulsion, whose composition and preparation method are basically the same as those of Example 4, except that the elastic emulsion is replaced by the emulsion of Comparative Example 1.

[0108] Comparative Example 4

[0109] A metal roof waterproof emulsion, whose raw material composition and preparation method are basically the same as those of Example 4, except that the elastic emulsion is replaced by the emulsion of Comparative Example 2.

[0110] Comparative Example 5

[0111] A metal roof waterproof coating whose raw material composition and preparation method are basically the same as those of Example 4, except that: the particle size of the heavy calcium is 300-400 mesh, the titanium dioxide is anatase titanium dioxide, and the barium sulfate is natural barium sulfate.

[0112] The single-component acrylic metal roof waterproof coatings prepared in Examples 4-6 and Comparative Examples 3-5 were subjected to performance tests.

[0113] Test methods for each performance indicator

[0114] With reference to the standard "JG / T 375-2012 Metal Roof Acrylic High Elastic Waterproof Coating", the single-component acrylic metal roof waterproof coating was subjected to tensile strength test, elongation at break test, low-temperature flexibility test, impermeability test and tear strength test.

[0115] The test results of each performance indicator are as follows:

[0116]

[0117] It can be seen from the test results in the above table that the inspection items of Examples 4-6 can all meet the requirements of the table standard, which shows that the metal roof waterproof coatings described in Examples 4-6 have good low-temperature flexibility and can meet the requirements of metal roofs for crack resistance and waterproofness.

[0118] The untreated tensile strength and tear strength of Comparative Example 4 are both lower than the standard, and the untreated tensile strength of Comparative Example 5 is high, but it fails the low-temperature bending test at -30°C. The main reason is that the emulsions used in Comparative Examples 4 and 5 are not elastic emulsions. Since the emulsions used in Comparative Examples 4 and 5 are elastic emulsions prepared by Comparative Examples 1 and 2, the ratio of soft monomers and hard monomers in the emulsions described in Comparative Examples 1 and 2 is unbalanced, so the theoretical glass transition temperature is either too high or too low, resulting in poor low-temperature flexibility of the emulsion, and ultimately insufficient tensile strength, tear strength or low-temperature bending performance of the metal roof waterproof coating; Comparative Example 6 has a large mesh number of added heavy calcium, so its untreated tensile strength and tear strength are both lower than the standard, and the acid-treated tensile strength retention rate has insufficient redundancy. Therefore, the mesh number of heavy calcium will also affect the mechanical properties of the coating.

[0119] It is understandable that those skilled in the art can make equivalent substitutions or changes based on the technical solution and inventive concept of the present invention, and all these changes or substitutions should fall within the protection scope of the claims attached to the present invention.

Claims

1. An elastic emulsion, characterized in that: The elastic emulsion comprises, by weight: 90 to 100 parts of deionized water, 88 to 88.5 parts of butyl acrylate, 3 to 5 parts of styrene, 4 to 5 parts of acrylonitrile, 1 to 2 parts of acrylic acid, 1 to 2 parts of acrylamide, 0.1 part of a silane coupling agent, 0.7 to 1.5 parts of an emulsifier, 0.3 to 0.5 parts of an initiator, 0.2 to 0.3 parts of an oxidant, 0.1 to 0.2 parts of a reducing agent, 0.4 to 0.8 parts of a pH regulator, 0.2 to 0.3 parts of a defoaming agent, and 0.4 to 0.7 parts of a bactericide.

2. The elastic emulsion according to claim 1, characterized in that The emulsifier comprises an anionic emulsifier and a nonionic emulsifier, and the weight ratio of the anionic emulsifier to the nonionic emulsifier is (1-2):

1.

3. The elastic emulsion according to claim 2, characterized in that The anionic emulsifier includes one or two of sodium dodecyl diphenyl ether disulfonate and ethoxylated alkyl sulfate sodium salt.

4. The elastic emulsion according to claim 2, characterized in that The nonionic emulsifier includes at least one of fatty alcohol polyoxyethylene ether and isomeric C13 fatty alcohol polyoxyethylene ether.

5. The elastic emulsion according to claim 1, characterized in that The silane coupling agent includes one or two of vinyl trimethoxy silane and glycidyl ether propyl trimethoxy silane.

6. A method for preparing an elastic emulsion, characterized in that: For preparing the elastic emulsion according to any one of claims 1 to 5, the method comprises the steps of: A01. Add 30 to 35 parts of deionized water and 0.1 to 0.15 parts of emulsifier to the polymerization kettle, stir and mix, and heat to 86 to 88 ° C to obtain a bottom material liquid; A02. Add the remaining emulsifier, 36 to 39 parts of deionized water, butyl acrylate, styrene, acrylonitrile, acrylic acid, acrylamide, and silane coupling agent into a pre-emulsification tank, stir and mix to obtain a pre-emulsion; A03. Add 0.05 to 0.1 parts of initiator and 0.5 to 1.5 parts of deionized water to the initiator tank A, and stir until completely dissolved to obtain an initiator solution A; A04. Add 0.2 to 0.4 parts of initiator and 5 to 7 parts of deionized water to the initiator tank B, and stir until completely dissolved to obtain an initiator solution B; A05. Add 0.2-0.4 parts of oxidant and 2-3 parts of deionized water to the oxidant tank, and stir until completely dissolved to obtain an oxidant solution; A06. Add 0.1 to 0.2 parts of reducing agent and 3 to 5 parts of deionized water to the reducing agent tank, and stir until completely dissolved to obtain a reducing agent solution; A07. Add 5% by weight of the pre-emulsion to the polymerization reactor, then add the initiator solution A, stir and mix, and keep warm for 15 minutes; add the remaining pre-emulsion and all the initiator solution B at a constant flow rate, and after the addition is completed, keep warm at 88 to 90 ° C for a certain period of time; A08. After the insulation is completed, the polymerization kettle is cooled to 75-80°C, and the oxidant solution and the reducing agent solution are added dropwise to the polymerization kettle; A09. Cool the polymerization kettle to below 50°C, add a pH adjuster to adjust the pH to 7-9, then add a defoamer and the remaining deionized water, stir and mix, filter the material, and obtain an elastic emulsion.

7. A metal roof waterproof coating, characterized in that: The composition comprises, by weight, 38 to 50 parts of elastic emulsion, 7 to 12 parts of deionized water, 24 to 35 parts of heavy calcium, 7 to 11 parts of barium sulfate, 3 to 5 parts of titanium dioxide, 0.3 to 0.4 parts of defoaming agent, 0.5 parts of dispersant, 0.2 to 0.3 parts of bactericide, 0 to 0.6 parts of flash rust inhibitor, 0.1 to 0.3 parts of pH regulator, 1 to 1.3 parts of antifreeze agent and 0.3 to 0.6 parts of thickener; the elastic emulsion is the elastic emulsion as claimed in any one of claims 1 to 6.

8. The metal roof waterproof coating according to claim 7, characterized in that: The particle size of the heavy calcium is 700-800 meshes.

9. The metal roof waterproof coating according to claim 7, characterized in that: The titanium dioxide is rutile titanium dioxide.

10. A method for preparing a metal waterproof coating, characterized in that: For preparing the metal waterproof coating according to any one of claims 7 to 9, the method comprises the steps of: B01. Add deionized water, defoamer, dispersant, pH adjuster, and antifreeze agent to a dispersion tank and stir at 600-800 rpm for 5-10 min. B02. Add heavy calcium, barium sulfate and titanium dioxide to a dispersion tank and stir at a speed of 1000-1500 rpm for 20-30 min; B03. Add filler to the dispersion tank, disperse evenly, add 0.2 parts of defoamer and bactericide, anti-flash rust agent, control the mixer speed to 600-1000 revolutions per minute, the mixing time is 20min; B04. After adding the defoamer and dispersing for 20 min, the emulsion was added and the mixer speed was controlled to 600-1000 rpm, and the mixing time was 20 min; B05. After adding the emulsion and dispersing for 20 min, a thickener was added to a suitable viscosity. The mixer speed was 600-1200 rpm, and the mixing time was 30 min; B06. Filter the mixed paint to remove impurities and residues to obtain acrylic roof metal waterproof coating.

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