阅读说明：本技术 一种持久自清洁的真石漆用核壳丙烯酸乳液及其制备方法 (Lasting self-cleaning core-shell acrylic emulsion for stone-like paint and preparation method thereof ) 是由 莫广强 梁健津 刘燕 于 2019-10-16 设计创作，主要内容包括：本发明公开一种持久自清洁的真石漆用核壳丙烯酸乳液,包括以下原料：苯乙烯、甲基丙烯酸烷基酯、丙烯酸烷基酯、功能单体、引发剂、乳化剂、去离子水、氨水,其制备方法包括：a)底料液A制备；b)预乳化液B制备；c)预乳化液C制备；d)滴加预乳化液反应；e)反应结束后保温、调pH值,出料。本发明采用核壳聚合技术形成硬核软壳的乳胶粒,高弹性率核提供持久自清洁效果的同时,具有一定刚性的软壳为漆膜提供了较好的成膜性,避免增塑剂的大量使用,降低了聚合物膜被水溶胀的风险,可有效地防止污染物粘附和渗透而影响漆膜外观。(The invention discloses a lasting self-cleaning core-shell acrylic emulsion for stone-like paint, which comprises the following raw materials: styrene, alkyl methacrylate, alkyl acrylate, functional monomer, initiator, emulsifier, deionized water and ammonia water, and the preparation method comprises the following steps: a) preparing a base material liquid A; b) preparing a pre-emulsion B; c) preparing a pre-emulsion C; d) dropwise adding the pre-emulsion for reaction; e) after the reaction is finished, preserving heat, adjusting the pH value and discharging. The invention adopts the core-shell polymerization technology to form the emulsion particles with hard cores and soft shells, the high-elasticity-rate core provides a lasting self-cleaning effect, and the soft shells with certain rigidity provide a paint film with better film-forming property, thereby avoiding the use of a large amount of plasticizer, reducing the risk of swelling of the polymer film, and effectively preventing pollutants from adhering and permeating to influence the appearance of the paint film.)

1. The lasting self-cleaning core-shell acrylic emulsion for the stone-like paint is characterized by comprising the following raw materials: styrene, alkyl methacrylate, alkyl acrylate, a functional monomer, an initiator, an emulsifier, deionized water and ammonia water;

the preparation method of the core-shell acrylic emulsion comprises the following steps:

a) preparing a base material liquid A: adding 15-20 parts of deionized water and 0.01-0.1 part of emulsifier into a polymerization kettle with a stirrer, a condenser and a constant flow pump feeding device, and heating until the temperature in the kettle reaches 85 ℃;

b) preparation of pre-emulsion B: adding 14-18 parts of deionized water, 0.3-0.35 part of emulsifier, 0-14 parts of styrene, 11-23 parts of alkyl methacrylate, 0.5-0.6 part of functional monomer and 0.02-0.05 part of initiator into a pre-emulsification tank with a monomer metering tank and a stirrer at normal temperature and normal pressure, and stirring for 15-20 minutes to uniformly mix for later use;

c) preparation of pre-emulsion C: adding 17-21 parts of deionized water, 0.22-0.24 part of emulsifier, 4-5 parts of styrene, 1.0-7.1 parts of alkyl methacrylate, 7-13 parts of alkyl acrylate, 1.6-1.65 parts of functional monomer and 0.02-0.04 part of initiator into a pre-emulsification tank with a monomer metering tank and a stirrer at normal temperature and normal pressure, and stirring for 15-20 minutes to mix uniformly for later use;

d) when the temperature in the polymerization kettle in the step a) reaches 85 ℃, quickly adding 5 percent of the total amount of the pre-emulsion B into the polymerization kettle by a constant flow pump feeding device, adding 0.05 part of an initiator, controlling the temperature in the kettle to be 85-88 ℃, keeping the temperature for 15min, dropwise adding the rest pre-emulsion B, controlling the dropwise adding time to be 105-130 min, keeping the temperature for 0.5 h after the dropwise adding is finished, keeping the temperature in the polymerization kettle to be 85-88 ℃, dropwise adding the pre-emulsion C, and controlling the dropwise adding time to be 80-125 min;

e) after the pre-emulsion C is dripped, keeping the temperature in the polymerization kettle constant at 88-90 ℃, preserving the heat for 1 hour, then reducing the temperature of the polymerization kettle to below 50 ℃, adjusting the pH to 7-8 by using 0.7-0.8 part of ammonia water, stirring for 20 minutes, filtering and discharging to obtain the lasting self-cleaning acrylic emulsion.

2. The self-cleaning lasting core-shell acrylic emulsion for stone-like paint as claimed in claim 1, wherein the alkyl methacrylate is at least one of methyl methacrylate and n-butyl methacrylate.

3. The self-cleaning lasting core-shell acrylic emulsion for stone-like paint as claimed in claim 1, wherein said alkyl acrylate is at least one of n-butyl acrylate, 2-ethylhexyl acrylate and tert-butyl acrylate.

4. The lasting self-cleaning core-shell acrylic emulsion for the stone-like paint as claimed in claim 1, wherein the functional monomer is at least three of vinyltrimethoxysilane, gamma-methacryloxypropyltrimethoxysilane, ethylene glycol dimethacrylate, allyl methacrylate, acrylamide and acrylic acid.

5. The durable self-cleaning core-shell acrylic emulsion for the stone-like paint as claimed in claim 1, wherein the initiator is at least one of sodium persulfate and potassium persulfate.

6. The self-cleaning lasting core-shell acrylic emulsion for stone-like paint as claimed in claim 1, wherein the emulsifier is at least one of sodium dodecyl benzene sulfonate, sodium dodecyl sulfate or fatty alcohol-polyoxyethylene ether.

Technical Field

The invention relates to a lasting self-cleaning core-shell acrylic emulsion for stone-like paint and a preparation method thereof, belonging to the field of stone-like paint for buildings.

Background

The stone paint is exactly like the decoration effect of marble, granite and the like, and the building decorated by the stone paint has the appearance similar to natural appearance, gives people elegant, solemn and harmonious aesthetic feeling, and is suitable for decoration of the inner wall and the outer wall of the building. Meanwhile, the stone-like paint has the characteristics of fire resistance, water resistance, acid and alkali resistance, no toxicity, no odor, strong bonding force, fastness and the like, can effectively prevent the corrosion of the external severe environment to the building, and prolongs the service life of the building. In addition, because good adhesive force and freeze-thaw resistance that possess, real mineral varnish still is fit for using in cold areas, and real mineral varnish quality is light moreover, compares traditional stone material and is difficult to drop, even drop also less to the injury of people, consequently people are more and more high to the likeness of real mineral varnish in recent years, and real mineral varnish producer is more and more.

After the general real stone paint construction is completed and completely dried, a layer of finish paint is brushed on the surface of the real stone paint to avoid the pollution of moisture and dust. However, because the real stone paint market competition is becoming fierce day by day, many real stone paint manufacturers and construction parties compete with the same row to improve profits, no finish treatment is carried out after the real stone paint construction, so that the constructed real stone paint has gradually dull appearance under the erosion of rainwater and dust, the color of the real stone paint is obviously different from that of the real stone paint during the construction, and the coating is not easy to wash and clean, thereby influencing the appearance of the building, and easily generating bad mood for the real stone paint prepared from the real stone paint emulsion. Therefore, the search for a stone-like paint emulsion with lasting self-cleaning performance is a technical problem to be solved urgently.

Disclosure of Invention

Aiming at the problems in the prior art, the invention provides a durable self-cleaning core-shell acrylic emulsion for stone-like paint and a preparation method thereof.

In order to achieve the purpose, the invention adopts the durable self-cleaning core-shell acrylic emulsion for the stone-like paint, which comprises the following raw materials: styrene, alkyl methacrylate, alkyl acrylate, a functional monomer, an initiator, an emulsifier, deionized water and ammonia water;

the preparation method of the core-shell acrylic emulsion comprises the following steps:

a) preparing a base material liquid A: adding 15-20 parts of deionized water and 0.01-0.1 part of emulsifier into a polymerization kettle with a stirrer, a condenser and a constant flow pump feeding device, and heating until the temperature in the kettle reaches 85 ℃;

b) preparation of pre-emulsion B: adding 14-18 parts of deionized water, 0.3-0.35 part of emulsifier, 0-14 parts of styrene, 11-23 parts of alkyl methacrylate, 0.5-0.6 part of functional monomer and 0.02-0.05 part of initiator into a pre-emulsification tank with a monomer metering tank and a stirrer at normal temperature and normal pressure, and stirring for 15-20 minutes to uniformly mix for later use;

c) preparation of pre-emulsion C: adding 17-21 parts of deionized water, 0.22-0.24 part of emulsifier, 4-5 parts of styrene, 1.0-7.1 parts of alkyl methacrylate, 7-13 parts of alkyl acrylate, 1.6-1.65 parts of functional monomer and 0.02-0.04 part of initiator into a pre-emulsification tank with a monomer metering tank and a stirrer at normal temperature and normal pressure, and stirring for 15-20 minutes to mix uniformly for later use;

d) when the temperature in the polymerization kettle in the step a) reaches 85 ℃, quickly adding 5 percent of the total amount of the pre-emulsion B into the polymerization kettle by a constant flow pump feeding device, adding 0.05 part of an initiator, controlling the temperature in the kettle to be 85-88 ℃, keeping the temperature for 15min, dropwise adding the rest pre-emulsion B, controlling the dropwise adding time to be 105-130 min, keeping the temperature for 0.5 h after the dropwise adding is finished, keeping the temperature in the polymerization kettle to be 85-88 ℃, dropwise adding the pre-emulsion C, and controlling the dropwise adding time to be 80-125 min;

e) after the pre-emulsion C is dripped, keeping the temperature in the polymerization kettle constant at 88-90 ℃, preserving the heat for 1 hour, then reducing the temperature of the polymerization kettle to below 50 ℃, adjusting the pH to 7-8 by using 0.7-0.8 part of ammonia water, stirring for 20 minutes, filtering and discharging to obtain the lasting self-cleaning acrylic emulsion.

The alkyl methacrylate adopts at least one of methyl methacrylate and n-butyl methacrylate.

The alkyl acrylate adopts at least one of n-butyl acrylate, 2-ethylhexyl acrylate and tert-butyl acrylate.

The functional monomer adopts at least three of vinyl trimethoxy silane, gamma-methacryloxypropyl trimethoxy silane, ethylene glycol dimethacrylate, allyl methacrylate, acrylamide and acrylic acid.

The initiator adopts at least one of sodium persulfate and potassium persulfate.

The emulsifier is at least one of sodium dodecyl benzene sulfonate, sodium dodecyl sulfate or fatty alcohol-polyoxyethylene ether.

Compared with the prior art, when the hard core and soft shell structure is synthesized by adopting a seed polymerization and gradient feeding method, the high Tg part is obviously higher than the normal temperature and is in a glass state, so that the high Tg part is not easy to swell by water, a pollution source is not easy to permeate, and the washing of rainwater on pollutants and the scratch resistance of a paint film are favorably improved; meanwhile, the part with lower Tg endows the emulsion with good film forming property, and the glassy part can be wrapped and bonded into a film, and the two parts form a good self-cleaning system together. In addition, the cross-linking agent is used for copolymerization modification, so that the elasticity rate of the hard core is enhanced, and the stability among core shells is enhanced; by using a proper amount of monomer with moderate Tg, the addition of soft monomer chain links is reduced, the shell layer elasticity rate is improved, the swelling and adhesion of moisture carrying fine dust to the emulsion film are reduced, and the influence on the attractiveness of the paint film is avoided.

The lasting self-cleaning acrylic emulsion consists of raw material components such as deionized water, an emulsifier, alkyl acrylate, alkyl methacrylate, a functional monomer, an initiator and the like. The raw material components are polymerized by a core-shell polymerization process, and a stable hard core and soft shell structure is formed by crosslinking modification, so that the stable lasting self-cleaning acrylic emulsion is obtained.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below. It should be understood, however, that the description herein of specific embodiments is only intended to illustrate the invention and not to limit the scope of the invention.