CN114316161A - Aqueous multistage copolymer dispersion, preparation method thereof and application thereof in preparation of finishing varnish - Google Patents
Aqueous multistage copolymer dispersion, preparation method thereof and application thereof in preparation of finishing varnish Download PDFInfo
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Abstract
The present invention relates to an aqueous multistage copolymer dispersion comprising at least one multistage copolymer comprising a tertiary copolymer made from a tertiary combination of monomers designed with a gradient Fox Tg, comprising: a first stage copolymer prepared from first stage combination monomers having a Fox Tg of 80-120 ℃; a second stage copolymer prepared from a second stage combination of monomers having a Fox Tg of 10-75 ℃; a third stage copolymer prepared from a third stage combination of monomers having a Fox Tg less than 10 ℃. The finishing varnish prepared from the aqueous multistage copolymer dispersion disclosed by the invention can keep high hardness at high temperature and has toughness at low temperature, so that the finishing varnish has high stain resistance and high water-white resistance.
Description
Technical Field
The invention relates to a water-based multistage copolymer dispersion, a preparation method thereof and application thereof in preparing finishing varnish with water-white resistance and stain resistance, such as preparation of water-based multistage copolymer dispersion for finishing varnish of interior and exterior walls of buildings.
Background
Along with the development of the technical level and the promotion of the living standard, people also become more and more severe to the requirement of coating, need satisfy basic demand simultaneously, life is more permanent, and water resistance is more excellent, and surface dust dirtiness is changeed and is washed the clearance etc.. In recent years, stone-like coatings are popular with users because of attractive appearance, natural color, stereoscopic impression and the like, but have the defects of relatively poor water resistance, water-white resistance, stain resistance, weather resistance and the like, so a layer of finishing varnish is required to be matched on the surface of the stone-like coatings to solve the problems, maintain the aesthetic feeling of the stone-like coatings and prolong the service life of the coatings. The existing finishing surface aqueous dispersion has the phenomena of hot stickiness and cold brittleness, the stain resistance performance is rapidly reduced due to the fact that the temperature is high, the problem of stickiness can be solved by increasing the glass transition temperature of emulsion, but the emulsion is easy to crack when used under the condition of low temperature, and therefore the stain resistance performance and the water-white resistance performance are difficult to achieve the satisfactory degree at the same time.
Although there is a design for improving the stain resistance by using a high Fox Tg copolymerized core-shell structure, for example, CN102977257A relates to a real stone paint emulsion with a water whitening resistant core-shell structure, the low Fox Tg copolymer of the core part brings the film forming property, and then the high Fox Tg copolymer of the shell layer of about 10% by mass improves the overall stain resistance. However, the structural design can cause the paint film to become brittle and not to form a continuous film when the mass ratio of the high Fox Tg copolymer is increased, the film forming performance of the paint film is seriously influenced, and even after the film is formed, the high Fox Tg copolymer and the low Fox Tg copolymer are separated, so that the stain resistance improving effect is limited. Patent CN106029720A also relates to a method for synthesizing multi-stage polymer, which uses high Fox Tg polymer as the second stage structure, so that the high Fox Tg polymer has the highest ratio of one sixth of the total structure weight, and thus the final anti-fouling performance is not significantly improved.
Accordingly, it is desirable in the art to develop an aqueous multistage copolymer dispersion that provides a finished varnish formulated therefrom with good film forming properties, is capable of maintaining high hardness at high temperatures, is tough at low temperatures, and has both high stain resistance and high water-white resistance.
Disclosure of Invention
Aiming at the problems in the prior art, the invention provides a waterborne multistage copolymer dispersion and a preparation method thereof, wherein the Fox Tg three-level gradient design of the copolymer, the Fox Tg design of the second-level copolymer and the third-level copolymer and the proportion of the Fox Tg design in the total mass are adjusted, so that the mass proportion of the first-level copolymer reaches more than 50% under the condition of ensuring good film-forming performance, and the finishing varnish prepared from the waterborne multistage copolymer dispersion can keep high hardness at high temperature and has toughness at low temperature, thereby realizing the performances of high stain resistance and high water-white resistance at the same time.
The present invention provides an aqueous multistage copolymer dispersion comprising at least one multistage copolymer comprising a tertiary copolymer made from tertiary combination monomers designed with a gradient Fox Tg comprising:
a first stage copolymer prepared from a first stage combination monomer having a Fox Tg of 80-120 deg.C, e.g., 85 deg.C, 90 deg.C, 95 deg.C, 100 deg.C, 105 deg.C, 110 deg.C, 115 deg.C, preferably 90-115 deg.C, more preferably 100 deg.C and 110 deg.C;
a second stage copolymer prepared from a second stage combination of monomers having a Fox Tg of 10-75 deg.C, e.g., 20 deg.C, 30 deg.C, 40 deg.C, 50 deg.C, 60 deg.C, 70 deg.C, preferably 15-60 deg.C, more preferably 20-40 deg.C;
a third copolymer prepared from third stage combination monomers having a Fox Tg less than 10 deg.C, e.g., 5 deg.C, 0 deg.C, -5 deg.C, -10 deg.C, -15 deg.C, -20 deg.C, preferably-20-5 deg.C, more preferably-10-0 deg.C.
In the present invention, the term Fox Tg refers to the glass transition temperature Tg calculated according to the Fox equation: 1/Tg ═ W1/Tg1+W2/Tg2+···+Wn/Tgn. Wherein W1、W2、…WnRespectively refers to the mass fraction of monomers 1, 2,. n, and the Tg of the combined monomers1、Tg2、…TgnRespectively refer to a combination sheetGlass transition temperature of homopolymer of monomer 1, 2,. n in bulk.
In the present invention, the multistage polymer is a multistage polymer comprising, based on 100% of the total mass thereof,
the first stage copolymer content is 50-60%, e.g., 52%, 54%, 56%, 58%, preferably 55-60%;
the second copolymer content is from 10 to 30% such as 15%, 20%, 25%, preferably from 15 to 25%, more preferably from 15 to 20%;
the third copolymer content is 10-30% such as 15%, 20%, 25%, preferably 15-25%, more preferably 15-20%.
In the invention, the multistage polymer can be in the form of particles with a multilayer core-shell structure, preferably particles with a three-layer core-shell structure, wherein the inner core layer contains a first-stage copolymer, the middle layer contains a second-stage copolymer, and the outer shell layer contains a third-stage copolymer;
preferably, the multistage polymer, the inner core layer is a first stage copolymer, the middle layer is a second stage copolymer, and the outer shell layer is a third stage copolymer.
The aqueous multistage copolymer dispersion of the present invention comprises one or more of the multistage copolymers in an aqueous medium, which may be, for example, an aqueous multistage copolymer emulsion; the one or more multistage copolymers means at least one, preferably one, of the multistage copolymers;
in a preferred embodiment, the one or more multistage copolymers may have a gradient structure resulting from the polymerization of three-stage monomers, such as a three-layer core-shell structured particle.
In the present invention, the monomer types of the first-stage combination monomers for preparing the first-stage copolymer, the second-stage combination monomers for preparing the second-stage copolymer and the third-stage combination monomers for preparing the third-stage copolymer are not particularly limited, and it suffices to make Fox Tg of each-stage combination monomers for preparing each-stage polymers within the range required by the present invention, provided that: the corresponding first stage copolymers, second stage copolymers and third stage copolymers prepared from the first stage combination monomers, second stage combination monomers and third stage combination monomers should all have respective Fox tgs consistent with the requirements of the present invention. Specifically, the Fox Tg of the first-stage combination monomers for preparing the first-stage copolymer is in the range of 80 to 120 ℃, preferably 90 to 115 ℃, more preferably 100-110 ℃; (ii) providing the Fox Tg of the second stage combination monomers from which the second stage copolymer is made to be in the range of from 10 to 75 deg.C, preferably from 15 to 60 deg.C, more preferably from 20 to 40 deg.C; the Fox Tg of the third stage combination monomers from which the third stage copolymer is made is below 10 deg.C, preferably in the range of-20-5 deg.C, more preferably-10-0 deg.C. The Fox Tg of the combined monomers is designed by a method known in the art, and the combined monomers can be combined and screened by a skilled person in the prior art according to actual needs, and the invention has no special requirement.
In the present invention, monomers that can be used to prepare the multistage polymer include hydrophobic unsaturated monomers and hydrophilic unsaturated monomers;
the hydrophobic monomer is selected from one or more of methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, tert-butyl (meth) acrylate, isobutyl (meth) acrylate, isobornyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate and styrene, and is preferably one or more of methyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isobornyl (meth) acrylate and styrene;
the hydrophilic monomer is selected from unsaturated carboxylic acids such as (meth) acrylic acid, itaconic acid, and maleic acid; unsaturated amides such as (meth) acrylamide, N-methylol (meth) acrylamide, 2-hydroxyethyl (meth) acrylamide; and hydroxyalkyl esters of unsaturated carboxylic acids, such as one or more of hydroxyethyl (meth) acrylate and hydroxypropyl (meth) acrylate, preferably one or more of (meth) acrylic acid, itaconic acid.
In a preferred embodiment, the first stage combination monomers used to prepare the first stage copolymer are selected from one or more of methyl (meth) acrylate, isobornyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, styrene, (meth) acrylic acid, itaconic acid, maleic acid, more preferably one or more of methyl (meth) acrylate, styrene, and (meth) acrylic acid.
In a preferred embodiment, the second stage combination monomers used to prepare the second stage copolymer are selected from one or more of methyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, styrene, (meth) acrylic acid, itaconic acid, more preferably one or more of methyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, and (meth) acrylic acid.
In a preferred embodiment, the third stage combination monomers used to prepare the third stage copolymer are selected from one or more of methyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, styrene, more preferably one or more of methyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate.
The aqueous multistage copolymer dispersions of the present invention can be prepared by a process comprising polymerization of a first stage combination monomer to produce a first stage copolymer and subsequent polymerization of a second stage combination monomer to produce a second stage copolymer followed by polymerization of a third stage combination monomer to produce a third stage copolymer. Multistage polymerization techniques known in the art can be used to prepare the aqueous multistage copolymer dispersions according to the present invention. For example, emulsion polymerization processes in aqueous media are suitable for use in the present invention.
Preferably, the aqueous multistage copolymer dispersion of the present invention is prepared by emulsion polymerization, optionally further comprising a surfactant, an initiator, a neutralizing agent, and the like as raw materials.
In this emulsion polymerization process, most conventional surfactants known to those skilled in the art can be used. In a preferred embodiment, the surfactant may be a non-reactive anionic and/or non-reactive nonionic surfactant;
the non-reactive anionic surfactant includes, for example, but is not limited to, one or more of alkyl, aryl or alkylaryl sulfates, sulfonates or phosphates, alkylsulfonic acids, sulfosuccinates, fatty alcohol ether sulfates, and fatty acids;
the non-reactive nonionic surfactant includes, for example, but is not limited to, one or more of alcohol or phenol ethoxylates, such as polyoxyethylene alkylphenyl ethers, including, but not limited to, sodium lauryl sulfate, sodium dodecylbenzene sulfonate, fatty alcohol polyoxyethylene ethers and salts thereof, and fatty alcohol ether phosphates and salts thereof.
The surfactant may also be a polymerizable surfactant containing at least one ethylenically unsaturated functional group, also known as a reactive surfactant; the polymerizable surfactant includes, for example, but is not limited to, an allyl polyoxyalkylene ether sulfate salt such as a sodium salt of an allyl polyoxyethylene alkyl ether sulfate, an allyl alkyl succinate sulfonate salt, an allyl ether hydroxypropanesulfonate salt such as a sodium salt, and a polyoxyethylene styrenated phenyl ether sulfate salt such as an ammonium salt.
The surfactant used in the present invention may be a non-reactive surfactant, a reactive surfactant, or a combination thereof.
Preferably, the total amount of the surfactants according to the invention is from 0.5 to 3%, for example from 1%, 1.5%, 2%, preferably from 0.8 to 1.5%, based on the total mass of the monomers of the respective combination.
In the emulsion polymerization process, it may be carried out in the presence of various common initiator systems, including, but not limited to, thermal initiators and/or redox initiators;
the thermal initiator is selected from one or more of ammonium persulfate, sodium persulfate, potassium persulfate and hydrogen peroxide;
the redox initiator typically comprises an oxidizing agent and a reducing agent; the oxidant is selected from one or more of ammonium persulfate, sodium persulfate, potassium persulfate and hydrogen peroxide, preferably one or more of ammonium persulfate, sodium persulfate and potassium persulfate;
the reducing agent is selected from one or more of alkali metal sulfites, such as potassium and/or sodium sulfites, alkali metal bisulfites, such as potassium and/or sodium bisulfites, alkali metal metabisulfites, such as potassium and/or sodium metabisulfites, formaldehyde sulfoxylates, such as potassium and/or sodium formaldehyde sulfoxylates, alkali metal salts of aliphatic sulfinic acids, preferably potassium and/or sodium salts, alkali metal hydrogen sulfides, such as potassium and/or sodium hydrogen sulfide, acetone bisulfites, such as sodium acetone bisulfite (2-hydroxy-2-propanesulfonic acid monosodium salt), ascorbic acid, isoascorbic acid.
Preferably, the total amount of initiator used according to the invention is between 0.2 and 2%, for example between 0.5%, 1.0%, 1.5%, preferably between 0.5 and 1%, of the total mass of the monomers of each combination.
The aqueous multistage copolymer dispersion preparation process of the present invention may also have a neutralizing agent added to the polymerization system, said neutralizing agent being generally selected from organic bases and/or inorganic bases;
the inorganic base is selected from one or more of ammonia, sodium hydroxide, potassium hydroxide and zinc oxide;
the organic base is selected from one or more of dimethylamine, diethylamine, triethylamine, monoethanolamine and triethanolamine.
Preferably, the addition of the neutralizing agent is terminated by adjusting the pH of the system to 7 to 10, preferably 7.5 to 9.5, more preferably 8 to 9.
In a preferred embodiment, the polymerization temperature in the emulsion polymerization process according to the invention is from 50 to 100 ℃ and preferably from 80 to 90 ℃. Depending on the various polymerization conditions, the polymerization can be carried out for several hours, for example from 2 to 8 hours, preferably from 2 to 6 hours.
The aqueous multistage copolymer dispersions according to the invention have a solids content of from 10 to 70% by weight, preferably from 35 to 60% by weight, more preferably from 40 to 55% by weight.
The aqueous multistage copolymer dispersions of the invention have a pH of from 7 to 10, preferably from 7.5 to 9.5, more preferably from 8 to 9.
The aqueous multistage copolymer dispersions of the invention have a copolymer particle size of from 50 to 500nm, preferably from 50 to 200nm, more preferably from 50 to 100 nm.
The invention also provides a preparation method of the aqueous multistage copolymer dispersion, which comprises the following steps:
1) mixing the first-stage combined monomer, part of surfactant and part of water to prepare a first-stage copolymer monomer pre-emulsion;
2) mixing the second-stage combined monomer, part of surfactant and part of water to prepare a second-stage copolymer monomer pre-emulsion;
3) mixing the third-stage combined monomer, part of surfactant and part of water to prepare a third-stage copolymer monomer pre-emulsion;
4) dissolving part of the initiator by using water to obtain a dropwise added initiator; dissolving the rest of initiator by water to obtain a kettle bottom initiator;
5) mixing the rest surfactant with water, stirring, heating to 80-85 deg.C, adding 3-10 wt% of first-stage copolymer monomer pre-emulsion, stirring, adding all kettle bottom initiators, and reacting at 80-85 deg.C for 10-30min to obtain seed emulsion;
6) controlling the temperature of the seed emulsion to be 80-85 ℃, adding the rest first-stage copolymer monomer pre-emulsion for 1-3h, after the addition is finished, sequentially adding the second-stage copolymer monomer pre-emulsion for 0.5-1h, adding the third-stage copolymer monomer pre-emulsion for 0.5-1h, adding a dropping initiator while adding the copolymer monomer pre-emulsion of each stage, and keeping the temperature of the copolymer monomer pre-emulsion of each stage for 0-60min, such as 10 min, 30min and 50min after the dropping is finished;
7) cooling the system to below 50 ℃ after heat preservation, adding a neutralizing agent to adjust the pH value to 7-9, stirring for 10-30min, and discharging.
In a preferred embodiment, the surfactant of step 1) is added in an amount of 20 to 60%, for example 30%, 40%, 50%, preferably 30 to 40% by weight of the total mass of the surfactant;
the addition amount of the surfactant in the step 2) is 5-20%, such as 8%, 10%, 15%, preferably 5-10% of the total mass of the surfactant;
the addition amount of the surfactant in the step 3) is 5-20% of the total mass of the surfactant, such as 8%, 10%, 15%, preferably 5-10%;
adding the rest of the surfactant in the step 5).
In a preferred embodiment, step 4) is to mix and dissolve 20 to 80%, such as 30%, 50%, 70%, preferably 40 to 60% of the total mass of the initiator with 4 to 10%, such as 5%, 7%, 9%, preferably 5 to 7% of the total mass of water to obtain a dropwise addition initiator; then mixing and dissolving the rest initiator and 1-4% of the total mass of water, such as 2%, 3%, 3.5%, preferably 1.5-3%, to obtain a kettle bottom initiator; in the above-mentioned preparation process, the addition of the initiator is well known in the art, and the dropwise addition initiator and the still bottom initiator, which are prepared separately, are added in two steps in a form of addition commonly used in the art and will not be described herein.
In a preferred embodiment, said first stage copolymer monomer pre-emulsion of step 5) for preparing the seed emulsion is added in an amount of 3 to 10%, such as 4%, 6%, 8%, preferably 3 to 5% of the total mass of the first stage copolymer monomer pre-emulsion.
In a preferred embodiment, the total amount of water used is from 40 to 900%, such as 50%, 150%, 200%, preferably 100-200% of the total mass of the combined monomers;
preferably, the water in step 1) is added in an amount of 20-60%, such as 30%, 40%, 50%, preferably 30-40% of the total mass of water;
the adding amount of the water in the step 2) is 5-20% of the total mass of the water, such as 8%, 10%, 15%, preferably 5-10%;
the adding amount of the water in the step 3) is 5-20% of the total mass of the water, such as 8%, 10%, 15%, preferably 5-10%;
in the step 4), the adding amount of water in the dropping initiator is 4-10% of the total mass of water, such as 5%, 7%, 9%, preferably 5-7%; the amount of water added to the kettle bottom initiator is 1-4% of the total mass of water, such as 2%, 3%, 3.5%, preferably 1.5-3%;
the remaining water was added in step 5).
The invention also provides application of the aqueous multistage copolymer dispersion in the fields of preparing exterior wall coatings, interior wall coatings, wood paints, printing ink, gloss oil and the like.
The aqueous multistage copolymer dispersoid can keep high hardness at high temperature, has good toughness at low temperature, has the advantages of excellent water white resistance, stain resistance, high gloss, high hardness and the like, is particularly suitable for the fields of external wall coating, internal wall coating, wood lacquer, printing ink, gloss oil and the like, and is particularly suitable for preparing water white resistance and stain resistance finishing varnish, such as outer layer finishing varnish of stone-like materials prepared by the aqueous multistage copolymer dispersoid, the reflection reduction index is found to be within 10 percent through the stain resistance test method of architectural coating, and meanwhile, the paint film is observed by visual observation to have no obvious whitening phenomenon after being soaked in water at normal temperature and low temperature for about 5 days. Compared with the prior art, the invention has the beneficial effects that:
according to the invention, by means of Fox Tg difference design of the multistage copolymer, the high-quality fraction ratio first-stage copolymer endows a paint film with higher hardness after film formation, and the third-stage copolymer enables the multistage copolymer to have better film-forming performance. The existence of the second-stage copolymer as a transition region of the first-stage copolymer and the third-stage copolymer enables the high hardness of a paint film to be maintained without affecting the film forming property through the introduction of the second-stage copolymer, and reduces the overhigh viscosity of the paint film caused by the overlow Fox Tg of the third-stage copolymer; for the water-white performance of a paint film, the copolymer with low Fox Tg has better film-forming performance, so that a formed film is more compact, and has a relatively hydrophobic molecular chain structure, so that the inward permeation of water molecules can be further slowed down, and the copolymer has excellent water-white resistance and excellent stain resistance.
Detailed Description
The present invention is further illustrated by the following specific examples, which are intended to be illustrative of the invention and are not to be construed as limiting the scope of the invention.
The information on the source of the raw materials used in the following examples is shown in Table 1 below, and other raw materials are common commercial raw materials unless otherwise specified:
TABLE 1 Main materials and sources
In the embodiment of the invention, each combined monomer Fox Tg (centigrade degree) is calculated according to the following formula:
in the formula W1、W2、…WnRespectively refers to the mass fraction of monomers 1, 2,. n in the combined monomers, Tg1、Tg2、…TgnEach refers to the glass transition temperature of the homopolymer of monomer 1, 2,. n in the combined monomers.
Example 1:
preparation of aqueous multistage copolymer dispersion:
the composition of the tertiary combined monomer is as follows:
the first-stage combined monomer comprises the following components: 49g of methyl methacrylate and 1g of acrylic acid, wherein the Fox Tg is 105 ℃;
the second-stage combined monomer comprises the following components: 16.5g of methyl methacrylate, 1g of butyl acrylate, 6.5g of 2-ethylhexyl acrylate, 1g of acrylic acid, and the Fox Tg of which is 19.7 ℃;
the third-stage combined monomer comprises the following components: 15.3g of methyl methacrylate, 4.7g of butyl acrylate and 5g of 2-ethylhexyl acrylate, and the Fox Tg is 9.4 ℃.
1) 50g of first-stage combined monomer, 0.5g of surfactant SDS and 25g of deionized water are mixed to prepare first-stage copolymer monomer pre-emulsion.
2) And mixing 25g of second-stage combined monomer, 0.25g of surfactant SDS and 10g of deionized water to prepare second-stage copolymer monomer pre-emulsion.
3) And mixing 25g of third-stage combined monomer, 0.25g of surfactant SDS and 10g of deionized water to prepare third-stage copolymer monomer pre-emulsion.
4) Dissolving 0.1g of initiator ammonium persulfate by 8g of water to obtain a dropwise addition initiator; dissolving 0.1g of the rest initiator ammonium persulfate by using 2g of water to obtain a kettle bottom initiator;
5) mixing 0.4g of surfactant SDS and 80g of deionized water, stirring, heating to 85 ℃, adding 2.26g of 3 wt% first-stage copolymer monomer pre-emulsion, adding a kettle bottom initiator after stirring uniformly, and reacting for 15min at 85 ℃ to obtain the seed emulsion.
6) Controlling the temperature of the seed emulsion to be 85 ℃, dropwise adding the rest first-stage copolymer monomer pre-emulsion for 90min, dropwise adding the second-stage copolymer monomer pre-emulsion 20min after finishing the feeding, dropwise adding the third-stage copolymer monomer pre-emulsion for 45min after finishing the feeding, and synchronously dropwise adding a dropwise adding initiator while dropwise adding the first-stage copolymer monomer pre-emulsion, the second-stage copolymer monomer pre-emulsion and the third-stage copolymer monomer pre-emulsion.
7) And cooling the system to below 50 ℃, adding 0.75g of ammonia water to adjust the pH value to 7-9, stirring for 30min, and discharging to obtain the aqueous multistage copolymer dispersoid.
The aqueous multistage copolymer dispersion had a solids content of 43% by weight, a polymer particle size of 80-90nm and a pH of 8.2.
The multistage polymer comprises the following components in percentage by mass: 50% of the first copolymer (inner core layer), 25% of the second copolymer (middle layer), 25% of the third copolymer (outer shell layer).
Example 2:
preparation of aqueous multistage copolymer dispersion:
the composition of the tertiary combined monomer is as follows:
the first-stage combined monomer comprises the following components: 59g of methyl methacrylate and 1g of acrylic acid, wherein the Fox Tg is 105 ℃;
the second-stage combined monomer comprises the following components: 13g of methyl methacrylate, 3g of butyl acrylate, 3g of 2-ethylhexyl acrylate and 1g of acrylic acid, wherein the Fox Tg is 26.9 ℃;
the third-stage combined monomer comprises the following components: 10g of methyl methacrylate, 5g of butyl acrylate and 5g of 2-ethylhexyl acrylate, and the Fox Tg is-9.4 ℃.
1) 60g of first-stage combined monomer, 0.6g of surfactant SDS and 25g of deionized water are mixed to prepare first-stage copolymer monomer pre-emulsion.
2) And mixing 20g of second-stage combined monomer, 0.2g of surfactant SDS and 10g of deionized water to prepare second-stage copolymer monomer pre-emulsion.
3) And mixing 20g of third-stage combined monomer, 0.2g of surfactant SDS and 10g of deionized water to prepare third-stage copolymer monomer pre-emulsion.
4) Dissolving 0.1g of initiator ammonium persulfate by 8g of water to obtain a dropwise addition initiator; dissolving 0.1g of the rest initiator ammonium persulfate by using 2g of water to obtain a kettle bottom initiator;
5) mixing 0.4g of surfactant SDS and 80g of deionized water, stirring, heating to 85 ℃, adding 2.57g of 3 wt% first-stage copolymer monomer pre-emulsion, adding a kettle bottom initiator after stirring uniformly, and reacting for 15min at 85 ℃ to obtain the seed emulsion.
6) Controlling the temperature of the seed emulsion to be 85 ℃, dropwise adding the rest first-stage copolymer monomer pre-emulsion for 108min, dropwise adding the second-stage copolymer monomer pre-emulsion 20min after finishing the feeding, dropwise adding the third-stage copolymer monomer pre-emulsion for 36min, dropwise adding the third-stage copolymer monomer pre-emulsion 20min after finishing the feeding, and synchronously dropwise adding the dropwise adding initiator while dropwise adding the first-stage copolymer monomer pre-emulsion, the second-stage copolymer monomer pre-emulsion and the third-stage copolymer monomer pre-emulsion.
7) And cooling the system to below 50 ℃, adding 0.75g of ammonia water to adjust the pH value to 7-9, stirring for 30min, and discharging to obtain the aqueous multistage copolymer dispersoid.
The aqueous multistage copolymer dispersion had a solids content of 43% by weight, a polymer particle size of 80-90nm and a pH of 8.3.
The multistage polymer comprises the following components in percentage by mass: 60% of the first copolymer (inner core layer), 20% of the second copolymer (middle layer), 20% of the third copolymer (outer shell layer).
Example 3:
preparation of aqueous multistage copolymer dispersion:
the composition of the tertiary combined monomer is as follows:
the first-stage combined monomer comprises the following components: 56g of methyl methacrylate, 3g of butyl acrylate and 1g of acrylic acid, wherein the Fox Tg is 91.8 ℃;
the second-stage combined monomer comprises the following components: 7.8g of methyl methacrylate, 1.2g of butyl acrylate and 1g of acrylic acid, wherein the Fox Tg is 74.8 ℃;
the third-stage combined monomer comprises the following components: 15g of methyl methacrylate, 7.5g of butyl acrylate and 7.5g of 2-ethylhexyl acrylate, and the Fox Tg is-9.4 ℃.
1) 60g of first-stage combined monomer, 0.6g of surfactant SDS and 25g of deionized water are mixed to prepare first-stage copolymer monomer pre-emulsion.
2) And mixing 10g of second-stage combined monomer, 0.1g of surfactant SDS and 5g of deionized water to prepare second-stage copolymer monomer pre-emulsion.
3) And mixing 30g of third-stage combined monomer, 0.3g of surfactant SDS and 15g of deionized water to prepare third-stage copolymer monomer pre-emulsion.
4) Dissolving 0.1g of initiator ammonium persulfate by 8g of water to obtain a dropwise addition initiator; dissolving 0.1g of the rest initiator ammonium persulfate by using 2g of water to obtain a kettle bottom initiator;
5) mixing 0.4g of surfactant SDS and 80g of deionized water, stirring, heating to 85 ℃, adding 2.57g of 3 wt% first-stage copolymer monomer pre-emulsion, adding a kettle bottom initiator after stirring uniformly, and reacting for 15min at 85 ℃ to obtain the seed emulsion.
6) Controlling the temperature of the seed emulsion to be 85 ℃, dropwise adding the rest of the first-stage copolymer monomer pre-emulsion for 108min, dropwise adding the second-stage copolymer monomer pre-emulsion 20min after finishing the feeding, dropwise adding the third-stage copolymer monomer pre-emulsion for 18min, dropwise adding the third-stage copolymer monomer pre-emulsion 20min after finishing the feeding, and dropwise adding the dropping initiator for 54min simultaneously and dropwise adding the first-stage copolymer monomer pre-emulsion, the second-stage copolymer monomer pre-emulsion and the third-stage copolymer monomer pre-emulsion.
7) And cooling the system to below 50 ℃, adding 0.75g of ammonia water to adjust the pH value to 7-9, stirring for 30min, and discharging to obtain the aqueous multistage copolymer dispersoid.
The aqueous multistage copolymer dispersion had a solids content of 43% by weight, a polymer particle size of 80-90nm and a pH of 8.5.
The multistage polymer comprises the following components in percentage by mass: 60% first stage copolymer (inner core layer), 10% second stage copolymer (middle layer), 30% third stage copolymer (outer shell layer).
Example 4:
preparation of aqueous multistage copolymer dispersion:
the composition of the tertiary combined monomer is as follows:
the first-stage combined monomer comprises the following components: 54g of methyl methacrylate, 3g of butyl acrylate, 2g of 2-ethylhexyl acrylate and 1g of acrylic acid, the Fox Tg being 80.3 ℃;
the second-stage combined monomer comprises the following components: 13g of methyl methacrylate, 3g of butyl acrylate, 3g of 2-ethylhexyl acrylate and 1g of acrylic acid, wherein the Fox Tg is 26.9 ℃;
the third-stage combined monomer comprises the following components: 5g of methyl methacrylate, 15g of 2-ethylhexyl acrylate and a Fox Tg of-57.9 ℃.
1) 60g of first-stage combined monomer, 0.6g of surfactant SDS and 25g of deionized water are mixed to prepare first-stage copolymer monomer pre-emulsion.
2) And mixing 20g of second-stage combined monomer, 0.2g of surfactant SDS and 10g of deionized water to prepare second-stage copolymer monomer pre-emulsion.
3) And mixing 20g of third-stage combined monomer, 0.2g of surfactant SDS and 10g of deionized water to prepare third-stage copolymer monomer pre-emulsion.
4) Dissolving 0.1g of initiator ammonium persulfate by 8g of water to obtain a dropwise addition initiator; dissolving 0.1g of the rest initiator ammonium persulfate by using 2g of water to obtain a kettle bottom initiator;
5) mixing 0.4g of surfactant SDS and 80g of deionized water, stirring, heating to 85 ℃, adding 2.57g of 3 wt% first-stage copolymer monomer pre-emulsion, adding a kettle bottom initiator after stirring uniformly, and reacting for 15min at 85 ℃ to obtain the seed emulsion.
6) Controlling the temperature of the seed emulsion to be 85 ℃, dropwise adding the rest first-stage copolymer monomer pre-emulsion for 108min, dropwise adding the second-stage copolymer monomer pre-emulsion 20min after finishing the feeding, dropwise adding the third-stage copolymer monomer pre-emulsion for 36min, dropwise adding the third-stage copolymer monomer pre-emulsion 20min after finishing the feeding, and synchronously dropwise adding the dropwise adding initiator while dropwise adding the first-stage copolymer monomer pre-emulsion, the second-stage copolymer monomer pre-emulsion and the third-stage copolymer monomer pre-emulsion.
7) And cooling the system to below 50 ℃, adding 0.75g of ammonia water to adjust the pH value to 7-9, stirring for 30min, and discharging to obtain the aqueous multistage copolymer dispersoid.
The aqueous multistage copolymer dispersion had a solids content of 43% by weight, a polymer particle size of 80-90nm and a pH of 8.43.
The multistage polymer comprises the following components in percentage by mass: 60% of the first copolymer (inner core layer), 20% of the second copolymer (middle layer), 20% of the third copolymer (outer shell layer).
Example 5:
preparation of aqueous multistage copolymer dispersion:
the composition of the tertiary combined monomer is as follows:
the first-stage combined monomer comprises the following components: 57g of isobornyl methacrylate and 3g of methacrylic acid, wherein the Fox Tg is 113.16 ℃;
the second-stage combined monomer comprises the following components: 12.8g of methyl methacrylate, 6.2g of 2-ethylhexyl acrylate, 1g of acrylic acid, the Fox Tg being 14.9 ℃;
the third-stage combined monomer comprises the following components: 11g of methyl methacrylate, 9g of 2-ethylhexyl acrylate and a Fox Tg of-13.2 ℃.
1) 60g of first-stage combined monomer, 0.6g of surfactant SDS and 25g of deionized water are mixed to prepare first-stage copolymer monomer pre-emulsion.
2) And mixing 20g of second-stage combined monomer, 0.2g of surfactant SDS and 10g of deionized water to prepare second-stage copolymer monomer pre-emulsion.
3) And mixing 20g of third-stage combined monomer, 0.2g of surfactant SDS and 10g of deionized water to prepare third-stage copolymer monomer pre-emulsion.
4) Dissolving 0.1g of initiator ammonium persulfate by 8g of water to obtain a dropwise addition initiator; dissolving 0.1g of the rest initiator ammonium persulfate by using 2g of water to obtain a kettle bottom initiator;
5) mixing 0.4g of surfactant SDS and 80g of deionized water, stirring, heating to 85 ℃, adding 2.57g of 3 wt% first-stage copolymer monomer pre-emulsion, adding a kettle bottom initiator after stirring uniformly, and reacting for 15min at 85 ℃ to obtain the seed emulsion.
6) Controlling the temperature of the seed emulsion to be 85 ℃, dropwise adding the rest first-stage copolymer monomer pre-emulsion for 108min, dropwise adding the second-stage copolymer monomer pre-emulsion 20min after finishing the feeding, dropwise adding the third-stage copolymer monomer pre-emulsion for 36min, dropwise adding the third-stage copolymer monomer pre-emulsion 20min after finishing the feeding, and synchronously dropwise adding the dropwise adding initiator while dropwise adding the first-stage copolymer monomer pre-emulsion, the second-stage copolymer monomer pre-emulsion and the third-stage copolymer monomer pre-emulsion.
7) And cooling the system to below 50 ℃, adding 1.2g of ammonia water to adjust the pH value to 7-9, stirring for 30min, and discharging to obtain the aqueous multistage copolymer dispersoid.
The aqueous multistage copolymer dispersion had a solids content of 43% by weight, a polymer particle size of 80-90nm and a pH of 8.24.
The multistage polymer comprises the following components in percentage by mass: 60% of the first copolymer (inner core layer), 20% of the second copolymer (middle layer), 20% of the third copolymer (outer shell layer).
Example 6:
preparation of aqueous multistage copolymer dispersion:
the composition of the tertiary combined monomer is as follows:
the first-stage combined monomer comprises the following components: 59g of methyl methacrylate and 1g of acrylic acid, wherein the Fox Tg is 105.02 ℃;
the second-stage combined monomer comprises the following components: 13g of methyl methacrylate, 6g of butyl acrylate and 1g of acrylic acid, wherein the Fox Tg is 37.44 ℃;
the third-stage combined monomer comprises the following components: methyl methacrylate 9g, butyl acrylate 11g, Fox Tg of-2.85 ℃.
1) 60g of first-stage combined monomer, 0.6g of surfactant SDS and 25g of deionized water are mixed to prepare first-stage copolymer monomer pre-emulsion.
2) And mixing 20g of second-stage combined monomer, 0.2g of surfactant SDS and 10g of deionized water to prepare second-stage copolymer monomer pre-emulsion.
3) And mixing 20g of third-stage combined monomer, 0.2g of surfactant SDS and 10g of deionized water to prepare third-stage copolymer monomer pre-emulsion.
4) Dissolving 0.1g of initiator ammonium persulfate by 8g of water to obtain a dropwise addition initiator; dissolving 0.1g of the rest initiator ammonium persulfate by using 2g of water to obtain a kettle bottom initiator;
5) mixing 0.4g of surfactant SDS and 80g of deionized water, stirring, heating to 85 ℃, adding 2.57g of 3 wt% first-stage copolymer monomer pre-emulsion, adding a kettle bottom initiator after stirring uniformly, and reacting for 15min at 85 ℃ to obtain the seed emulsion.
6) Controlling the temperature of the seed emulsion to be 85 ℃, dropwise adding the rest first-stage copolymer monomer pre-emulsion for 108min, dropwise adding the second-stage copolymer monomer pre-emulsion 20min after finishing the feeding, dropwise adding the third-stage copolymer monomer pre-emulsion for 36min, dropwise adding the third-stage copolymer monomer pre-emulsion 20min after finishing the feeding, and synchronously dropwise adding the dropwise adding initiator while dropwise adding the first-stage copolymer monomer pre-emulsion, the second-stage copolymer monomer pre-emulsion and the third-stage copolymer monomer pre-emulsion.
7) And cooling the system to below 50 ℃, adding 0.75g of ammonia water to adjust the pH value to 7-9, stirring for 30min, and discharging to obtain the aqueous multistage copolymer dispersoid.
The aqueous multistage copolymer dispersion had a solids content of 43% by weight, a polymer particle size of 80-90nm and a pH of 8.64.
The multistage polymer comprises the following components in percentage by mass: 60% of the first copolymer (inner core layer), 20% of the second copolymer (middle layer), 20% of the third copolymer (outer shell layer).
Comparative example 1:
preparation of aqueous multistage copolymer dispersion:
reference is made to example 1 with the following differences: omitting the second-stage combined monomer from the third-stage combined monomer, correspondingly omitting the operation related to the second-stage combined monomer in the preparation process, and keeping other conditions unchanged to prepare the aqueous multistage copolymer dispersion, wherein the solid content is 43 wt%, the polymer particle size is 80-90nm, and the pH is 8.43.
The multistage polymer comprises the following components in percentage by mass: 66.7% first stage copolymer (inner core layer), 33.3% third stage copolymer (outer shell layer).
Comparative example 2:
preparation of aqueous multistage copolymer dispersion:
reference is made to example 1 with the following differences: the first-stage combined monomer is omitted from the third-stage combined monomer, and the second-stage combined monomer is used for replacing the first-stage combined monomer in the preparation process, and other conditions are unchanged, so that the aqueous multistage copolymer dispersion is prepared, the solid content is 43 wt%, the polymer particle size is 80-90nm, and the pH is 8.11.
The multistage polymer comprises the following components in percentage by mass: 50% second stage copolymer (inner core layer), 50% third stage copolymer (outer shell layer).
Comparative example 3:
preparation of a homogeneous copolymer dispersion:
reference is made to example 1 with the following differences: and omitting the third-stage combined monomer from the third-stage combined monomers, correspondingly omitting the operation related to the third-stage combined monomer in the preparation process, and keeping other conditions unchanged to prepare the aqueous multistage copolymer dispersion, wherein the solid content is 43 wt%, the polymer particle size is 80-90nm, and the pH is 8.43.
The multistage polymer comprises the following components in percentage by mass: 66.7% first stage copolymer (inner core layer), 33.3% second stage copolymer (outer shell layer).
Comparative example 4:
preparation of aqueous multistage copolymer dispersion:
with reference to example 2, the difference is that: the original first-stage combined monomer and the original third-stage combined monomer are exchanged, namely the first-stage combined monomer comprises the following components: 10g of methyl methacrylate, 5g of butyl acrylate and 5g of 2-ethylhexyl acrylate, wherein the Fox Tg is-9.4 ℃;
the second-stage combined monomer comprises the following components: 13g of methyl methacrylate, 3g of butyl acrylate, 3g of 2-ethylhexyl acrylate and 1g of acrylic acid, wherein the Fox Tg is 26.9 ℃;
the third-stage combined monomer comprises the following components: 59g of methyl methacrylate, 1g of acrylic acid and a Fox Tg of 105 ℃.
The relevant operations were correspondingly interchanged during the preparation of example 2, and the other conditions were unchanged, to give an aqueous multistage copolymer dispersion having a solids content of 43% by weight, a polymer particle size of 90 to 100nm and a pH of 8.27.
The multistage polymer comprises the following components in percentage by mass: 20% of the first copolymer (inner core layer), 20% of the second copolymer (middle layer), 60% of the third copolymer (outer shell layer).
Comparative example 5:
preparation of aqueous multistage copolymer dispersion:
referring to example 2, except that the second stage combination monomer composition was replaced with: methyl methacrylate 10g, butyl acrylate 4.5g, 2-ethylhexyl acrylate 4.5g, acrylic acid 1g, Fox Tg of-1.16 ℃ and the other conditions were unchanged.
An aqueous multistage copolymer dispersion having a solids content of 43% by weight, a polymer particle size of 80 to 90nm and a pH of 8.5 was obtained by the procedure of example 2.
The multistage polymer comprises the following components in percentage by mass: 60% of the first copolymer (inner core layer), 20% of the second copolymer (middle layer), 20% of the third copolymer (outer shell layer).
Comparative example 6:
preparation of aqueous multistage copolymer dispersion:
referring to example 2, except that the third stage combination monomer composition was replaced with: methyl methacrylate 12g, butyl acrylate 4g, 2-ethylhexyl acrylate 4g, Fox Tg 7.57 ℃ and the other conditions were unchanged.
An aqueous multistage copolymer dispersion having a solids content of 43% by weight, a polymer particle size of 80 to 90nm and a pH of 8.43 was obtained by the procedure of example 2.
The multistage polymer comprises the following components in percentage by mass: 60% of the first copolymer (inner core layer), 20% of the second copolymer (middle layer), 20% of the third copolymer (outer shell layer).
Comparative example 7:
preparation of aqueous multistage copolymer dispersion:
referring to example 2, except that the third stage combination monomer composition was replaced with: 51g of methyl methacrylate, 8g of 2-ethylhexyl acrylate and 1g of acrylic acid, the Fox Tg being 60.14 ℃ and the other conditions being unchanged.
An aqueous multistage copolymer dispersion having a solids content of 43% by weight, a polymer particle size of 90 to 100nm and a pH of 8.24 was obtained by the procedure of example 2.
The multistage polymer comprises the following components in percentage by mass: 60% of the first copolymer (inner core layer), 20% of the second copolymer (middle layer), 20% of the third copolymer (outer shell layer).
Comparative example 8:
preparation of aqueous multistage copolymer dispersion:
referring to example 2, except that the polymer ratio of each stage was adjusted, the composition of the three-stage combination monomer was replaced with:
the first-stage combined monomer comprises the following components: 69g of methyl methacrylate and 1g of acrylic acid, wherein the Fox Tg is 105 ℃;
the second-stage combined monomer comprises the following components: 9.5g of methyl methacrylate, 2.25g of butyl acrylate, 2.25g of 2-ethylhexyl acrylate, 1g of acrylic acid, and 26.9 ℃ of Fox Tg;
the third-stage combined monomer comprises the following components: 7.5g of methyl methacrylate, 3.75g of butyl acrylate and 3.75g of 2-ethylhexyl acrylate, wherein the Fox Tg is-9.4 ℃; other conditions were unchanged.
An aqueous multistage copolymer dispersion having a solids content of 43% by weight, a polymer particle size of 80 to 90nm and a pH of 8.16 was obtained by the procedure of example 2.
The multistage polymer comprises the following components in percentage by mass: 70% first stage copolymer (inner core layer), 15% second stage copolymer (middle layer), 15% third stage copolymer (outer shell layer).
The multistage copolymer dispersions prepared in examples 1 to 6 and comparative examples 1 to 8 were formulated into finishing varnishes according to the formulation of Table 2 and tested for their properties in the following manner:
TABLE 2 formulation composition of top-coat varnish
| Raw materials | Weight/% of |
| Multistage copolymer dispersions | 50 |
| Deionized water | 44 |
| Film-forming aid (Texanol) | 5 |
| Antifreeze (propylene glycol) | 0.3 |
| PH regulator (AMP-95) | 0.2 |
| Thickening agent (U505) | 0.5 |
The performance test method adopted by the invention is as follows:
hardness: measuring the room temperature hardness of the paint film according to GB/T6739-1996 pencil hardness measuring method, and in order to judge the hardness of the paint film under the high temperature condition, placing the prepared paint film in an oven at 60 ℃ for 30min and then detecting;
temperature change resistance: the toughness of the paint film is detected according to JG/T25-2017 'temperature change resistance test method for architectural coating', the paint film is placed in a 50 ℃ oven for 3 hours and then placed at-20 ℃ for 3 hours, and the paint film is still normal and has no crack after three cycles and is qualified;
contamination resistance: carrying out stain resistance test according to GB/T9780-2013' test method for stain resistance of architectural coating (the lower the reduction rate coefficient, the better the performance is shown);
water whitening: water-white resistance was performed on multi-color paint substrates, and the discoloration was observed and scored according to the instructions in table 3;
film forming temperature: readings were taken by the minimum film formation temperature tester standard test method.
TABLE 3 Water-whitening resistance Scoring standards
| Evaluation of Water whitening | Water white condition |
| 5 | Has no blushing effect |
| 4 | Slight whitish and hardly visible |
| 3 | Moderate blushing is easy to find |
| 2 | Severe whiting, clearly visible |
| 1 | Severe whitening and complete whitening |
Results of performance testing of the finishes formulated from the multistage copolymer dispersions prepared in examples 1-6 and comparative examples 1-8 are shown in Table 4
Table 4 test results of properties of the top-coat varnish
| Water white | Stain resistant | Film formation temperature | Hardness at room temperature | Hardness at 60 DEG C | Resistance to temperature change | |
| Example 1 | 5 | 5.00％ | 25℃ | H | H | Qualified |
| Example 2 | 5 | 2.40％ | 35℃ | 3H | 2H | Qualified |
| Example 3 | 5 | 3.80％ | 33℃ | 2H | H | Qualified |
| Example 4 | 5 | 6.00％ | 30℃ | H | HB | Qualified |
| Example 5 | 5 | 4.50％ | 30℃ | H | H | Qualified |
| Example 6 | 4 | 1.70％ | 35℃ | 3H | 3H | Qualified |
| Comparative example 1 | 5 | 15.00％ | 15℃ | 2B | 3B | Qualified |
| Comparative example 2 | 5 | 20.40％ | 5℃ | 4B | 6B | Qualified |
| Comparative example 3 | 2 | 18.00％ | 60℃ | H | 2B | Fail to be qualified |
| Comparative example 4 | N.A | N.A | Does not form a film | N.A | N.A | Fail to be qualified |
| Comparative example 5 | 5 | 12.40％ | 20℃ | B | 3B | Qualified |
| Comparative example 6 | 2 | 11.40％ | 42℃ | 3H | 2H | Fail to be qualified |
| Comparative example 7 | 5 | 15.00％ | 21℃ | B | 3B | Qualified |
| Comparative example 8 | N.A | N.A | Does not form a film | N.A | N.A | Fail to be qualified |
Note: 1. n.a means no relevant data was obtained. 2. Temperature change resistance: the paint film is normal and undamaged, and the paint film is qualified; film cracking or cracked indicates failure.
Finally, it should be noted that the above-mentioned embodiments only illustrate the preferred embodiments of the present invention, and do not limit the scope of the present invention, and although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that various changes and modifications can be made by modifying the technical solution of the present invention or equivalent substitutions within the scope of the present invention defined by the claims.
Claims (10)
1. An aqueous multistage copolymer dispersion comprising at least one multistage copolymer comprising a tertiary copolymer made from a tertiary combination of monomers designed with a gradient Fox Tg comprising:
a first stage copolymer prepared from first stage combination monomers having a Fox Tg of 80-120 deg.C, preferably 90-115 deg.C, more preferably 100-110 deg.C;
a second stage copolymer prepared from a second stage combination of monomers having a Fox Tg of from 10 to 75 deg.C, preferably from 15 to 60 deg.C, more preferably from 20 to 40 deg.C;
a third stage copolymer prepared from a third stage combination of monomers having a Fox Tg of less than 10 ℃, preferably-20-5 ℃, more preferably-10-0 ℃.
2. The aqueous multistage copolymer dispersion according to claim 1, wherein the multistage polymer is present in an amount of 100% by weight of the total mass of the multistage polymer,
the first-stage copolymer content is from 50 to 60%, preferably from 55 to 60%;
the content of the second copolymer is 10 to 30%, preferably 15 to 25%, more preferably 15 to 20%;
the content of the third copolymer is 10 to 30%, preferably 15 to 25%, more preferably 15 to 20%.
3. The aqueous multistage copolymer dispersion according to claim 1 or 2, wherein the multistage polymer may be in the form of particles of a multilayer core-shell structure, preferably particles of a three-layer core-shell structure, wherein the inner core layer comprises the first stage copolymer, the middle layer comprises the second stage copolymer and the outer shell layer comprises the third stage copolymer;
preferably, the multistage polymer, the inner core layer is a first stage copolymer, the middle layer is a second stage copolymer, and the outer shell layer is a third stage copolymer.
Preferably, the aqueous multistage copolymer dispersion comprises one or more of said multistage copolymers in an aqueous medium, said one or more multistage copolymers referring to at least one, preferably one, of said multistage copolymers.
4. The aqueous multistage copolymer dispersion as claimed in any of claims 1 to 3, wherein the monomer species of the first stage combination monomer for preparing the first stage copolymer, the second stage combination monomer for preparing the second stage copolymer and the third stage combination monomer for preparing the third stage copolymer are required to be such that the Fox Tg of the first stage combination monomer for preparing the first stage copolymer is in the range of 80 to 120 ℃, preferably 90 to 115 ℃, more preferably 100-; (ii) providing the Fox Tg of the second stage combination monomers from which the second stage copolymer is made to be in the range of from 10 to 75 deg.C, preferably from 15 to 60 deg.C, more preferably from 20 to 40 deg.C; the Fox Tg of the third stage combination monomers from which the third stage copolymer is made is below 10 deg.C, preferably in the range of-20-5 deg.C, more preferably-10-0 deg.C.
5. The aqueous multistage copolymer dispersion according to any of claims 1 to 4 wherein the monomers used to prepare the multistage polymer comprise a hydrophobic unsaturated monomer and a hydrophilic unsaturated monomer;
the hydrophobic monomer is selected from one or more of methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, tert-butyl (meth) acrylate, isobutyl (meth) acrylate, isobornyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate and styrene, and is preferably one or more of methyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isobornyl (meth) acrylate and styrene;
the hydrophilic monomer is selected from unsaturated carboxylic acids such as (meth) acrylic acid, itaconic acid, and maleic acid; unsaturated amides such as (meth) acrylamide, N-methylol (meth) acrylamide, 2-hydroxyethyl (meth) acrylamide; and hydroxyalkyl esters of unsaturated carboxylic acids, such as one or more of hydroxyethyl (meth) acrylate and hydroxypropyl (meth) acrylate, preferably one or more of (meth) acrylic acid, itaconic acid.
6. The aqueous multistage copolymer dispersion as claimed in any of claims 1 to 5,
the first-stage combined monomer used for preparing the first-stage copolymer is selected from one or more of methyl (meth) acrylate, isobornyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, styrene, (meth) acrylic acid, itaconic acid and maleic acid, and is more preferably one or more of methyl (meth) acrylate, styrene and (meth) acrylic acid;
the second-stage combined monomer used for preparing the second-stage copolymer is selected from one or more of methyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, styrene, (meth) acrylic acid, itaconic acid, more preferably one or more of methyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, and (meth) acrylic acid;
the third-stage combination monomer used for preparing the third-stage copolymer is selected from one or more of methyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate and styrene, and more preferably one or more of methyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate and stearyl (meth) acrylate.
7. The aqueous multistage copolymer dispersion according to any of claims 1 to 6 wherein the aqueous multistage copolymer dispersion is prepared by emulsion polymerization, the starting materials of which optionally further comprise surfactants, initiators, neutralizers;
the surfactant is selected from non-reactive anionic and/or non-reactive nonionic surfactants; the non-reactive anionic surfactant is selected from one or more of alkyl, aryl or alkylaryl sulfate, sulfonate or phosphate, alkyl sulfonic acid, sulfosuccinate, fatty alcohol ether sulfate and fatty acid; the non-reactive nonionic surfactant is selected from one or more of alcohol or phenol ethoxylate, preferably polyoxyethylene alkyl phenyl ether, more preferably sodium dodecyl sulfate, sodium dodecyl benzene sulfonate, fatty alcohol-polyoxyethylene ether and salts thereof, and fatty alcohol ether phosphate and salts thereof;
preferably, the total dosage of the surfactant is 0.5-3%, preferably 0.8-1.5% of the total mass of each combined monomer;
the initiator is selected from a thermal initiator and/or a redox initiator; the thermal initiator is selected from one or more of ammonium persulfate, sodium persulfate, potassium persulfate and hydrogen peroxide; the redox initiator comprises an oxidizing agent and a reducing agent; the oxidant is selected from one or more of ammonium persulfate, sodium persulfate, potassium persulfate and hydrogen peroxide, preferably one or more of ammonium persulfate, sodium persulfate and potassium persulfate; the reducing agent is selected from alkali metal sulfite, preferably one or more of potassium and/or sodium salt, alkali metal hydrogen sulfide, acetone bisulfite, ascorbic acid and isoascorbic acid;
preferably, the total using amount of the initiator is 0.2-2%, preferably 0.5-1% of the total mass of all the combined monomers;
the neutralizing agent is generally selected from organic and/or inorganic bases; the inorganic base is selected from one or more of ammonia, sodium hydroxide, potassium hydroxide and zinc oxide; the organic base is selected from one or more of dimethylamine, diethylamine, triethylamine, monoethanolamine and triethanolamine;
preferably, the addition amount of the neutralizing agent is adjusted to the end point of the system pH of 7 to 10, preferably 7.5 to 9.5, more preferably 8 to 9;
the emulsion polymerization is carried out at the polymerization temperature of 50-100 ℃, preferably 80-90 ℃ and the polymerization time of 2-8h, preferably 2-6 h.
8. A process for preparing an aqueous multistage copolymer dispersion according to any of claims 1 to 7 comprising the steps of:
1) mixing the first-stage combined monomer, part of surfactant and part of water to prepare a first-stage copolymer monomer pre-emulsion;
2) mixing the second-stage combined monomer, part of surfactant and part of water to prepare a second-stage copolymer monomer pre-emulsion;
3) mixing the third-stage combined monomer, part of surfactant and part of water to prepare a third-stage copolymer monomer pre-emulsion;
4) dissolving part of the initiator by using water to obtain a dropwise added initiator; dissolving the rest of initiator by water to obtain a kettle bottom initiator;
5) mixing the rest surfactant with water, stirring, heating to 80-85 deg.C, adding 3-10 wt% of first-stage copolymer monomer pre-emulsion, stirring, adding all kettle bottom initiators, and reacting at 80-85 deg.C for 10-30min to obtain seed emulsion;
6) controlling the temperature of the seed emulsion to be 80-85 ℃, adding the rest first-stage copolymer monomer pre-emulsion for 1-3h, after the addition is finished, sequentially adding the second-stage copolymer monomer pre-emulsion for 0.5-1h, adding the third-stage copolymer monomer pre-emulsion for 0.5-1h, adding a dropping initiator while adding the copolymer monomer pre-emulsion for each stage, and keeping the temperature of each stage of copolymer monomer pre-emulsion for 0-60min after the dropping is finished;
7) cooling the system to below 50 ℃ after heat preservation, adding a neutralizing agent to adjust the pH value to 7-9, stirring for 10-30min, and discharging.
9. The preparation method according to claim 8, wherein the surfactant is added in the step 1) in an amount of 20 to 60%, preferably 30 to 40%, based on the total mass of the surfactant;
preferably, the addition amount of the surfactant in the step 2) is 5-20% of the total mass of the surfactant, and more preferably 5-10%;
preferably, the addition amount of the surfactant in the step 3) is 5-20% of the total mass of the surfactant, and more preferably 5-10%;
adding the rest of the surfactant in the step 5);
step 4) mixing and dissolving 20-80%, preferably 40-60% of the total mass of the initiator and 4-10%, preferably 5-7% of the total mass of water to obtain a dropwise addition initiator; then mixing and dissolving the rest initiator and 1-4%, preferably 1.5-3% of the total mass of water to obtain a kettle bottom initiator;
step 5) adding the first-stage copolymer monomer pre-emulsion for preparing the seed emulsion in an amount of 3-10%, preferably 3-5%, of the total mass of the first-stage copolymer monomer pre-emulsion;
the total amount of the water is 40-900% of the total mass of the combined monomers, preferably 100-200%;
preferably, the adding amount of the water in the step 1) is 20-60% of the total mass of the water, and more preferably 30-40%;
preferably, the adding amount of the water in the step 2) is 5-20% of the total mass of the water, and more preferably 5-10%;
preferably, the adding amount of the water in the step 3) is 5-20% of the total mass of the water, and more preferably 5-10%;
preferably, in the step 4), the adding amount of water in the dropwise adding initiator is 4-10% of the total mass of water, and more preferably 5-7%; the adding amount of water in the kettle bottom initiator is 1-4% of the total mass of water, and more preferably 1.5-3%;
the remaining water was added in step 5).
10. Use of the aqueous multistage copolymer dispersion according to any of claims 1 to 7 or of the aqueous multistage copolymer dispersion prepared by the process according to claims 8 or 9 in the field of exterior wall coatings, interior wall coatings, wood lacquers, inks varnishes, in particular for the preparation of water-white-resistant, stain-resistant finishes.
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| CN102977257A (en) * | 2012-12-25 | 2013-03-20 | 上海三瑞高分子材料有限公司 | Water-whitening proof maishi paint emulsion of core-shell structure and method for preparing same |
| CN106029720A (en) * | 2013-12-13 | 2016-10-12 | 巴斯夫欧洲公司 | Multistage polymers and compositions thereof |
| CN110964400A (en) * | 2019-12-04 | 2020-04-07 | 中国科学院化学研究所 | Aqueous wood lacquer emulsion and preparation method and application thereof |
-
2022
- 2022-01-12 CN CN202210029792.XA patent/CN114316161A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002012601A (en) * | 2000-06-30 | 2002-01-15 | Saiden Chemical Industry Co Ltd | Method for manufacturing aqueous polymer dispersion for coating material and the dispersion |
| CN102977257A (en) * | 2012-12-25 | 2013-03-20 | 上海三瑞高分子材料有限公司 | Water-whitening proof maishi paint emulsion of core-shell structure and method for preparing same |
| CN106029720A (en) * | 2013-12-13 | 2016-10-12 | 巴斯夫欧洲公司 | Multistage polymers and compositions thereof |
| CN110964400A (en) * | 2019-12-04 | 2020-04-07 | 中国科学院化学研究所 | Aqueous wood lacquer emulsion and preparation method and application thereof |
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