Cyclodextrin modified polymer and preparation method and application thereof
阅读说明：本技术 一种环糊精改性聚合物及其制备方法和用途 (Cyclodextrin modified polymer and preparation method and application thereof ) 是由 张抒 秦佃斌 纪学顺 孙家宽 于 2021-06-25 设计创作，主要内容包括：本发明公开了一种环糊精改性聚合物及其制备方法和用途,所述环糊精改性聚合物,其特征在于,包括如下重量比的聚合单体,以聚合单体的总质量计：不饱和羧酸单体A 15-50wt％,优选20-40wt％,不饱和疏水单体B 25-50wt％,优选25-40wt％,不饱和烯烃类单体C 15-40％,优选20-35wt％,含环糊精的不饱和单体D 5-20wt％,优选8-15wt％。本发明中环糊精改性聚合物对有机/无机颜填料都具有良好的分散效率,且浆料稳定性好。(The invention discloses a cyclodextrin modified polymer, a preparation method and application thereof, wherein the cyclodextrin modified polymer is characterized by comprising the following polymerized monomers in percentage by weight, based on the total mass of the polymerized monomers: 15-50 wt%, preferably 20-40 wt%, of unsaturated carboxylic acid monomer A, 25-50 wt%, preferably 25-40 wt%, of unsaturated hydrophobic monomer B, 15-40 wt%, preferably 20-35 wt%, of unsaturated olefinic monomer C, and 5-20 wt%, preferably 8-15 wt%, of cyclodextrin-containing unsaturated monomer D. The cyclodextrin modified polymer has good dispersion efficiency on organic/inorganic pigments and fillers, and the slurry stability is good.)
1. A cyclodextrin modified polymer comprising polymerized monomers in the following weight ratios, based on the total mass of the polymerized monomers:
unsaturated carboxylic acid monomers A15-50 wt.%, preferably 20-40 wt.%,
from 25 to 50% by weight, preferably from 25 to 40% by weight, of unsaturated hydrophobic monomers B,
unsaturated olefinic monomers C15-40%, preferably 20-35% by weight,
the cyclodextrin-containing unsaturated monomers D are from 5 to 20% by weight, preferably from 8 to 15% by weight.
2. The cyclodextrin modified polymer of claim 1, wherein the unsaturated hydrophobic monomer B is acrylic acid C1-C30Alkyl ester monomer or styrene monomer or their mixture, preferably acrylic acid C1-C10Alkyl ester monomers or styrene monomers or a mixture of the alkyl ester monomers and the styrene monomers;
more preferably, the acrylic acid C1-C10The alkyl ester monomer is one or more of methyl acrylate, butyl acrylate, isooctyl acrylate, methyl methacrylate, butyl methacrylate and isooctyl methacrylate; the styrene compoundThe monomer is one or more of styrene, a-methyl styrene and a-ethyl styrene.
3. The cyclodextrin-modified polymer of claim 1, wherein the cyclodextrin-containing unsaturated monomer D is a reaction product of cyclodextrin and an epoxy-containing unsaturated monomer E;
preferably, the cyclodextrin is one or more of alpha-cyclodextrin, beta-cyclodextrin, gamma-cyclodextrin and derivatives thereof, more preferably beta-cyclodextrin;
preferably, the unsaturated monomer E containing epoxy group is one or more of allyl glycidyl ether, glycidyl methacrylate and derivatives thereof, preferably one or two of allyl glycidyl ether and glycidyl methacrylate.
4. The cyclodextrin modified polymer of any of claims 1-3, wherein the unsaturated carboxylic acid monomer A is one or more of acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, crotonic acid, mesaconic acid, citraconic acid, and fumaric acid, preferably one or more of acrylic acid, methacrylic acid, maleic acid;
the unsaturated olefin monomer C is C with carbon atom number5-C18Preferably one or more of unsaturated olefins of C5-C10More preferably one or more of pentene, hexene, heptene or diisobutylene.
5. A process for the preparation of a cyclodextrin modified polymer of any of claims 1-4, comprising the steps of:
1) preparation of unsaturated monomers D containing Cyclodextrin
Dissolving cyclodextrin in an alkaline aqueous solution, adding an unsaturated monomer E containing an epoxy group, and reacting at 30-80 ℃ for 2-10h to prepare an unsaturated monomer D containing cyclodextrin;
2) adding a monomer A, B, C, D into an organic solvent, and heating and polymerizing in the presence of an initiator and a chain transfer agent to obtain the cyclodextrin modified polymer.
6. The process for preparing cyclodextrin-modified polymer of claim 5, wherein in step 1), the molar ratio of cyclodextrin to epoxy group-containing unsaturated monomer E is 1:1 to 3, preferably 1: 1;
preferably, after the reaction in step 1) is completed, adding acid to adjust the pH value to 6-7, then adding an ether solvent to precipitate a product, and filtering to obtain the unsaturated monomer D containing cyclodextrin.
7. The method of claim 6, wherein the polymerization conditions in step 2) are as follows: the reaction temperature is 60-140 ℃, and the preferable temperature is 70-120 ℃; the reaction time is 2-8h, preferably 4-6 h.
8. The method for preparing cyclodextrin modified polymer of claim 7, wherein said initiator is organic initiator, and the amount of addition is 0.5-10%, preferably 2-6% of total mass of monomer A, B, C, D; preferably, the initiator is one or more of azobisisobutyronitrile, azobisisovaleronitrile, azobisisoheptonitrile, dilauroyl peroxide, dibenzoyl peroxide, tert-butyl peroxyisobutyrate, tert-butyl peroxypivalate, diisopropyl peroxydicarbonate and di-tert-butyl peroxide, and more preferably one or more of azobisisobutyronitrile, azobisisovaleronitrile, azobisisoheptonitrile, dilauroyl peroxide and dibenzoyl peroxide;
preferably, the chain transfer agent is one or more of a-methylstyrene linear dimer and a mercapto group-containing monomer; the mercapto-containing monomer is preferably one or more of n-dodecyl mercaptan, tert-dodecyl mercaptan, hexadecyl mercaptan, octadecyl mercaptan, thioglycolic acid and mercaptoethanol; the amount of the chain transfer agent added is 0.5 to 8%, preferably 2 to 6% of the total mass of the monomer A, B, C, D.
9. The process for preparing cyclodextrin-modified polymer of claim 7, wherein after the completion of the reaction in step 2), the solvent is removed under reduced pressure, and water is added to obtain a product having a solid content of 40-60 wt% and a pH of 7-11, preferably a product having a solid content of 45-55 wt% and a pH of 7-9.
10. Use of a cyclodextrin-modified polymer according to any of claims 1 to 4 for the preparation of coatings containing solid pigments and fillers, printing inks, leather, textile dyes, pastes, pigment concentrates, ceramics, cosmetic preparations; the color filler is inorganic color filler or organic color filler or a mixture of organic and inorganic color fillers;
preferably, the cyclodextrin modified polymer is added in each formulation in an amount of 1 to 15 wt%, preferably 1 to 10 wt%, of the total mass of the pigments and fillers.
Technical Field
The invention relates to a polymer, in particular to a cyclodextrin modified polymer and a preparation method and application thereof.
Background
The dispersing agent is an assistant for dispersing the pigment and the filler, is adsorbed on the surface of the pigment and the filler through an anchoring group, and keeps the particles stable through electrostatic repulsion and/or steric hindrance, so that the pigment and the filler are uniformly distributed in a system. In the fields of paint, printing ink, color paste and the like, the dispersion of the pigment and the filler is an important technical link, and the selection of a proper dispersant can improve the important performances of the system such as storage stability, gloss, colorability, color development and the like.
With increasingly stringent environmental requirements, there is an increasing demand for aqueous dispersant products. Most of the traditional aqueous dispersants are carboxylic acid homopolymer or copolymer or polyurethane oligomer, and the carboxylic acid homopolymer dispersant is used for dispersing inorganic pigments through ion adsorption and is easily influenced by temperature, pH and ions, so that the system is unstable. The carboxylic acid copolymer and polyurethane oligomer dispersant can adsorb pigments through pigment-philic groups, but the dispersing and stabilizing effects of the dispersant on non-polar pigments still need to be improved; in addition, organic solvents, mercapto chain transfer agents and amine neutralizing agents are often used in the preparation process, so that the product has a large odor.
Cyclodextrins are the general term for a series of cyclic oligosaccharides produced by amylose under the action of cyclodextrin glycosyltransferase produced by Bacillus, usually containing 6-12D-glucopyranose units. Because the cyclodextrin is hydrophilic at its outer edge and hydrophobic in its inner cavity, it can provide a hydrophobic binding site like an enzyme, serving as a host to encapsulate various suitable guests, such as organic molecules, inorganic ions, and gas molecules. The hydrophobic property of the inner cavity and the hydrophilic property of the outer part enable the inner cavity to form an inclusion compound and a molecular assembly system with a plurality of organic and inorganic molecules according to Van der Waals force, hydrophobic interaction force, matching action among host molecules and guest molecules and the like. It has been found that the use of cyclodextrin to modify polymers to prepare dispersants can improve the dispersion and stability of dispersants for non-polar pigments, such as organic pigments having high aromatic hydrocarbon content. In addition, through cyclodextrin modification, the odor of the polymer can be obviously reduced, and the use experience of a user is improved.
Patent CN103357346B discloses a dispersant of beta-cyclodextrin modified polymethacrylate, which can be used to disperse pigment powder containing aromatic groups because the beta-cyclodextrin group is a pigment affinity group and can bond with aromatic groups in the pigment molecular structure, but the dispersant can only be used in oily systems. Patent CN107603347A discloses a copolymer dispersant of cyclodextrin and oleic acid, which can obtain a super-dispersible dispersant because the cyclodextrin has a hole capable of accommodating part of organic pigment, and the polymer is compounded with a suitable surfactant, but the dispersant does not have a suitable solvation chain, resulting in poor stability in an aqueous system. Patent CN108486925A discloses a polymer dispersant of beta-cyclodextrin modified acrylic resin, which can promote the uniform dispersion of dye in water-based dye and increase the suspension rate, but the dispersant can only disperse hydrophilic (polar) pigment.
In addition, the cyclodextrin modified polymers disclosed in the prior art are generally prepared by an esterification method, and the conversion rate of the process is low. Therefore, how to use cyclodextrin to prepare a low-odor polymer dispersant product which can disperse polar and nonpolar pigments and has high dispersion efficiency and good stability becomes very important.
Disclosure of Invention
In order to solve the technical problems, the invention firstly provides a cyclodextrin modified polymer, which can be used for dispersing organic pigments and fillers and inorganic pigments and fillers through special molecular structure design, has high dispersion efficiency, and has excellent stability. The invention also provides a preparation method of the cyclodextrin modified polymer, and the polymer can be simply and efficiently prepared by the method. The invention also provides the application of the cyclodextrin modified polymer as a dispersing agent in the fields of water-based paint, ink, color paste and the like, and the cyclodextrin modified polymer has good compatibility with other components in an application formula and good stability.
In order to achieve the purpose, the technical scheme adopted by the invention is as follows:
a cyclodextrin modified polymer comprising polymerized monomers in the following weight ratios, based on the total mass of the polymerized monomers:
15 to 50 wt.%, preferably 20 to 40 wt.%,
from 25 to 50% by weight, preferably from 25 to 40% by weight, of unsaturated hydrophobic monomers B,
unsaturated olefinic monomers C15-40%, preferably 20-35% by weight,
the cyclodextrin-containing unsaturated monomers D are from 5 to 20% by weight, preferably from 8 to 15% by weight.
In a further embodiment, the unsaturated hydrophobic monomer B is acrylic acid C1-C30Alkyl ester monomer or styrene monomer or their mixture, preferably acrylic acid C1-C10Alkyl ester monomers or styrene monomers or a mixture of the alkyl ester monomers and the styrene monomers;
more preferably, the acrylic acid C1-C10The alkyl ester monomer is one or more of methyl acrylate, butyl acrylate, isooctyl acrylate, methyl methacrylate, butyl methacrylate and isooctyl methacrylate; the styrene monomer is one or more of styrene, a-methyl styrene and a-ethyl styrene.
In a further embodiment, the cyclodextrin-containing unsaturated monomer D is a reaction product of cyclodextrin and an epoxy-containing unsaturated monomer E;
preferably, the cyclodextrin is one or more of alpha-cyclodextrin, beta-cyclodextrin, gamma-cyclodextrin and derivatives thereof, more preferably beta-cyclodextrin;
preferably, the unsaturated monomer E containing epoxy group is one or more of allyl glycidyl ether, glycidyl methacrylate and derivatives thereof, preferably one or two of allyl glycidyl ether and glycidyl methacrylate.
In a further embodiment, the unsaturated carboxylic acid monomer a is one or more of acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, crotonic acid, mesaconic acid, citraconic acid, and fumaric acid, preferably one or more of acrylic acid, methacrylic acid, maleic acid;
the unsaturated olefin monomer C is C with carbon atom number5-C18Of unsaturated olefinsOr more, preferably C, carbon number5-C10More preferably one or more of pentene, hexene, heptene or diisobutylene.
Further, the cyclodextrin-modified polymer of the present invention has a weight average molecular weight of 10000-.
A process for the preparation of a cyclodextrin modified polymer as hereinbefore described comprising the steps of:
1) preparation of unsaturated monomers D containing Cyclodextrin
Dissolving cyclodextrin in alkaline aqueous solution (such as 10-20 wt% sodium hydroxide solution), adding unsaturated monomer E containing epoxy group, and reacting at 30-80 deg.C for 2-10h to obtain unsaturated monomer D containing cyclodextrin;
2) adding a monomer A, B, C, D into an organic solvent, and heating and polymerizing in the presence of an initiator and a chain transfer agent to obtain the cyclodextrin modified polymer.
In a further embodiment, in step 1), the molar ratio of cyclodextrin to epoxy group-containing unsaturated monomer E is from 1:1 to 3, preferably 1: 1;
preferably, after the reaction in step 1) is completed, adding acid to adjust the pH to 6-7, then adding an ether solvent (such as petroleum ether) to precipitate a product, and filtering to obtain the unsaturated monomer D containing cyclodextrin.
In a further specific embodiment, in step 2), the polymerization reaction is a thermally initiated radical polymerization, and the high reaction temperature is favorable for improving the monomer conversion rate, but the prepared prepolymer has low molecular weight; the low reaction temperature results in low monomer conversion and the high molecular weight of the prepolymer. In order to ensure a high monomer conversion and to keep the molecular weight of the prepolymer within the range of the present invention, the reaction conditions are preferably: the reaction temperature is 60-140 ℃, and the preferable temperature is 70-120 ℃; the reaction time is 2-8h, preferably 4-6 h.
In some preferred examples, the raw materials for the polymerization reaction are added in the following manner: adding an organic solvent into a reactor with a heating device, a heat transferring device and a stirrer, heating to a reaction temperature, and simultaneously dropwise adding a mixed solution of the monomer A, B, C, D and the chain transfer agent and an initiator solution into the reactor for 1-7h, preferably 3-5 h. After the dropwise addition, the temperature is kept for 1h for curing.
In a further embodiment, the initiator is an organic initiator, preferably one or more of azobisisobutyronitrile, azobisisovaleronitrile, azobisisoheptonitrile, dilauroyl peroxide, dibenzoyl peroxide, tert-butyl peroxyisobutyrate, tert-butyl peroxypivalate, diisopropyl peroxydicarbonate, di-tert-butyl peroxide, more preferably one or more of azobisisobutyronitrile, azobisisovaleronitrile, azobisisoheptonitrile, dilauroyl peroxide, dibenzoyl peroxide;
the addition amount of the initiator affects the molecular weight of the prepolymer and the monomer conversion rate, and when the addition amount is high, the monomer conversion rate is high, but the molecular weight of the polymer is low; the conversion rate of the monomer is low when the addition amount is low, and the molecular weight of the polymer is high. In order to ensure high monomer conversion and the prepolymer molecular weight is in a preferred range, the addition amount thereof is 0.5 to 10%, preferably 2 to 6%, of the total mass of the monomer A, B, C, D; the initiator may be dissolved in an organic solvent in advance before the addition, and the concentration thereof is not particularly limited so as to completely dissolve the initiator.
The polymerization reaction requires the addition of a chain transfer agent in the presence of an initiator. The chain transfer agent can effectively control the molecular weight and distribution of the prepolymer, so that the structural design and application performance of the prepolymer can be optimized. Preferably, the chain transfer agent is one or more of a-methylstyrene linear dimer and a mercapto group-containing monomer; the mercapto-containing monomer is preferably one or more of n-dodecyl mercaptan, tert-dodecyl mercaptan, hexadecyl mercaptan, octadecyl mercaptan, thioglycolic acid and mercaptoethanol; the chain transfer agent is added in an amount of 0.5 to 8%, preferably 2 to 6% of the total mass of the monomer A, B, C, D in order to obtain a prepolymer of the desired molecular weight and distribution.
Preferably, the organic solvent is selected from one or more of alcohol ether solvents, such as one or more of ethylene glycol methyl ether, ethylene glycol butyl ether, propylene glycol methyl ether, propylene glycol butyl ether, dipropylene glycol methyl ether, propylene glycol methyl ether acetate, and the like, preferably one or more of propylene glycol methyl ether, propylene glycol butyl ether, dipropylene glycol methyl ether; the dosage of the organic solvent is 150 percent, preferably 150 percent of the total mass of the monomer A, B, C, D; controlling the amount of the organic solvent added within this range can ensure that the viscosity remains low during the polymerization process, which is beneficial to improving the monomer conversion rate.
In a further embodiment, after the reaction in step 2) is completed, the solvent is removed under reduced pressure, and in some instances, it is preferred to add appropriate amounts of base and water to adjust the cyclodextrin modified polymer to the final aqueous solution product to obtain an aqueous solution of the cyclodextrin modified polymer.
Preferably, the aqueous solution is from 40 to 60 wt% solids, preferably from 45 to 55 wt% solids, such as 50% solids. The pH of the aqueous solution is in the range of 7 to 11, preferably 7 to 9. The pH can be adjusted by using alkali metal hydroxides or organic amines, such as sodium hydroxide, potassium hydroxide, ammonia, triethylamine, N-dimethylethanolamine, diethylethanolamine, 2-amino-2-methylpropanol. Preferably, the water and the alkali are added into the reactor at one time, and the reaction is continued for 0.5 to 2 hours, preferably 0.5 to 1 hour after the addition to obtain the aqueous solution of the cyclodextrin modified polymer.
Use of a cyclodextrin-modified polymer as hereinbefore described for the preparation of coatings, printing inks, leather, textile dyes, pastes, pigment concentrates, ceramics, cosmetic formulations containing solid pigments and fillers; the cyclodextrin modified polymer is particularly suitable to be used as a dispersant for various pigments and fillers, wherein the pigments and fillers are inorganic pigments and fillers or organic pigments and fillers or a mixture of organic pigments and inorganic pigments and fillers; the inorganic pigment and filler comprises one or more of carbon black, graphite, calcium carbonate, talcum powder, titanium dioxide, zinc oxide, zinc sulfide, zinc phosphate, barium sulfate, iron oxide, manganese phosphate, cobalt aluminate, cobalt stannate, cobalt zincate, antimony oxide, antimony sulfide, chromium oxide and the like; the organic pigment fillers include, for example, one or more of mono-, di-, tri-and higher azo pigments, oxazine, dioxazine, thiazine pigments, phenylmethane, triarylmethane, xanthene, diketopyrrolopyrrole, phthalocyanines, ultramarine and other metal complex pigments, indigo pigments, methine pigments, anthraquinone, pyranthrone, bisacridine, quinacridone, perylene and other polycyclic carbonyl pigments. Preferably, the cyclodextrin modified polymer is added in each formulation in an amount of 1 to 15 wt%, preferably 1 to 10 wt%, of the total mass of the pigments and fillers.
The invention adopts the four monomers with the specific structure and the specific proportion for copolymerization to prepare the polymer dispersant with the cyclodextrin structure. By introducing the cyclodextrin monomer with a special structure, the hydrophilicity of the polymer can be improved, and a (nonpolar) pigment group can be brought, so that the dispersibility of the dispersing agent and the stability in an aqueous system can be improved. The polymer dispersant contains a hydrophilic carboxylic acid chain segment, an acrylate hydrophobic chain segment, an alkane hydrophobic chain segment and a cyclodextrin group, and under the synergistic action of the chain segments, the polymer can disperse inorganic pigments and fillers and organic pigments and fillers through electrostatic repulsion, and the stability of the pigments and fillers in a system is greatly improved. In addition, the cyclodextrin is introduced into the polymer, so that the polymer has the characteristic of low odor and good compatibility with systems such as water-based paint, ink and the like, and can bring important properties such as excellent gloss, coloring, color spreading and the like to the systems while improving the dispersion efficiency and stability.
Compared with the prior art, the invention has the beneficial effects that:
1. the preparation method adopts the conventional free radical polymerization to generate the polymer containing the cyclodextrin group, and can avoid the defects of low monomer conversion rate, high energy consumption and the like caused by the esterification process; moreover, the method has mild conditions for removing the organic solvent, can reduce energy consumption and avoid polymer decomposition caused by high-temperature flash evaporation, and is easier to realize industrialization.
2. The polymer prepared by the invention has hydrophilic carboxylic acid chain segments, hydrophobic acrylate/styrene and alkane chain segments, so that the polymer has solvation chains in organic and inorganic pigments and fillers, and the stability of the pigments and fillers in a system can be greatly improved.
3. The polymer has good compatibility with systems such as water-based paint, printing ink and the like, improves the dispersion efficiency and stability, and can bring important properties such as excellent gloss, color development, water resistance and the like to the systems.
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 first, the embodiment of the invention and the comparative example have the following main raw material sources:
(meth) acrylic acid and esters, styrenic monomers: vanhua chemical group, Inc.;
cyclodextrin: wake chemical Co., Ltd;
alcohol ether solvent: (ii) the chemistry of the dow;
other common raw materials are commercially available materials unless otherwise specified.
Second, the embodiment of the invention and the comparative example adopt the main testing apparatus and method:
polymer weight average molecular weight: GPC measurement, model number is Optilab T-Rex/Viscostar-II/HELEOS-II.
Preparation of monomer D1 [ preparation example 1 ]
200g of beta-cyclodextrin is dissolved in 100g of 10 wt% aqueous sodium hydroxide solution, 21g of allyl glycidyl ether is added to react for 5 hours at 50 ℃, hydrochloric acid is added dropwise to adjust the pH value to 7, petroleum ether is added to precipitate a reaction product, and the monomer D1 is obtained through filtration and drying.
Preparation of monomer D2 [ preparation example 2 ]
200g of beta-cyclodextrin is dissolved in 120g of 20 wt% aqueous sodium hydroxide solution, 25g of glycidyl methacrylate is added, reaction is carried out for 5h at 50 ℃, then hydrochloric acid is dropwise added to adjust the pH value to 6-7, petroleum ether is added to precipitate a reaction product, and the monomer D2 is obtained after filtration and drying.
[ example 1 ]
(1) 185g of propylene glycol methyl ether was charged into a 1L round-bottom four-neck flask equipped with a stirrer, a condenser and a feed inlet, dissolved with stirring and heated to 110 ℃. An initiator mixture of 30g of acrylic acid, 60g of methyl methacrylate, 60g of diisobutylene, 20g of monomer D1 and 6g a-methyl styrene linear dimer, 2g of dibenzoyl peroxide and 15g of propylene glycol methyl ether was prepared. And synchronously dropwise adding the prepared two mixtures into a reactor, starting polymerization reaction, wherein the dropwise adding time is 5h, and after the dropwise adding is finished, continuously carrying out heat preservation reaction for 1 h.
(2) After the reaction is finished, the solvent is removed by reduced pressure distillation, then water is added to adjust the solid content to 45 percent, and sodium hydroxide is added to adjust the pH value to 8.
GPC measurement the weight average molecular weight of the polymer prepared in this example was 35620.
[ example 2 ]
(1) 220g of propylene glycol methyl ether was added to a 1L round-bottom four-neck flask equipped with a stirrer, a condenser and a feed inlet, and heated to 100 ℃ after dissolution with stirring. An initiator mixture of 80g of methacrylic acid, 50g of butyl acrylate, 30g of heptene, 10g of monomer D2 and 5g of n-dodecanethiol, 6g of dilauroyl peroxide and 30g of propylene glycol methyl ether was prepared. And synchronously dropwise adding the prepared two mixtures into a reactor, starting polymerization reaction, wherein the dropwise adding time is 4h, and after the dropwise adding is finished, continuously carrying out heat preservation reaction for 1 h.
(2) After the reaction is finished, the solvent is removed by reduced pressure distillation, then water is added to adjust the solid content to 42 percent, and sodium hydroxide is added to adjust the pH value to 9.
The weight average molecular weight of the polymer prepared in this example was 27654 using GPC measurement.
[ example 3 ]
(1) 150g of dipropylene glycol methyl ether was added to a 1L round-bottom four-necked flask equipped with a stirrer, a condenser and a charge port, and after dissolving with stirring, the mixture was heated to 90 ℃. An initiator mixture of 40g of crotonic acid, 80g of styrene, 35g of hexene, 15g of monomer D1 and 2g of tert-dodecyl mercaptan, 10g of azobisisoheptonitrile and 30g of propylene glycol methyl ether was prepared. And synchronously dropwise adding the prepared two mixtures into a reactor, starting polymerization reaction, wherein the dropwise adding time is 3h, and after the dropwise adding is finished, continuously carrying out heat preservation reaction for 1 h.
(2) After the reaction is finished, the solvent is removed by reduced pressure distillation, then water is added to adjust the solid content to 50 percent, and sodium hydroxide is added to adjust the pH value to 7.
The weight average molecular weight of the polymer prepared in this example was 20136 by GPC measurement.
[ example 4 ]
(1) Into a 1L round-bottom four-necked flask equipped with a stirrer, a condenser and a charge port, 200g of propylene glycol monomethyl ether acetate was charged, dissolved with stirring, and then heated to 75 ℃. An initiator mixture of 45g of maleic acid, 55g of isooctyl methacrylate, 40g of diisobutylene, 30g of monomer D2 and 5g a-methylstyrene linear dimer, 12g of azobisisobutyronitrile and 30g of propylene glycol methyl ether was prepared. And synchronously dropwise adding the prepared two mixtures into a reactor, starting polymerization reaction, wherein the dropwise adding time is 6h, and after the dropwise adding is finished, continuously carrying out heat preservation reaction for 1 h.
(2) After the reaction is finished, the solvent is removed by reduced pressure distillation, then water is added to adjust the solid content to 45 percent, and sodium hydroxide is added to adjust the pH value to 10.
The weight average molecular weight of the polymer prepared in this example was 14883 using GPC measurement.
Comparative example 1
Polymerization was carried out in substantially the same manner as in example 1 and polymer solutions of the same solids and pH were prepared, except that: monomer D1 was not added to the polymerization. The final polymer weight average molecular weight was 26587 using GPC.
Comparative example 2
Polymerization was carried out in substantially the same manner as in example 1 and polymer solutions of the same solids and pH were prepared, except that: the monomer D1 is not added in the polymerization reaction, and cyclodextrin is added for esterification after the polymerization reaction is finished, and the specific scheme is as follows:
(1) 185g of propylene glycol methyl ether was charged into a 1L round-bottom four-neck flask equipped with a stirrer, a condenser and a feed inlet, dissolved with stirring and heated to 110 ℃. An initiator mixture of 30g of acrylic acid, 60g of methyl methacrylate, 60g of diisobutylene and 6g a-methylstyrene linear dimer, 2g of dibenzoyl peroxide and 15g of propylene glycol methyl ether was prepared. And synchronously dropwise adding the prepared two mixtures into a reactor, starting polymerization reaction, wherein the dropwise adding time is 5h, and after the dropwise adding is finished, continuously carrying out heat preservation reaction for 1 h.
(2) After the reaction is finished, 20g of beta-cyclodextrin and 1g of zinc oxide catalyst are added into the polymerization solution, and the temperature is raised to 180 ℃ for reaction for 4 hours.
(3) After the reaction is finished, the solvent is removed by reduced pressure distillation, then water is added to adjust the solid content to 45 percent, and sodium hydroxide is added to adjust the pH value to 8.
The final polymer weight average molecular weight was 30154 using GPC testing and the polymer esterification rate was only 60% using a potentiometric titrator.
Comparative example 3
(1) 185g of propylene glycol methyl ether was charged into a 1L round-bottom four-neck flask equipped with a stirrer, a condenser and a feed inlet, dissolved with stirring and heated to 110 ℃. An initiator mixture of 30g of acrylic acid, 60g of methyl methacrylate, 60g of diisobutylene, 40g of monomer D1 and 6g a-methyl styrene linear dimer, 2g of dibenzoyl peroxide and 15g of propylene glycol methyl ether was prepared. And synchronously dropwise adding the prepared two mixtures into a reactor, starting polymerization reaction, wherein the dropwise adding time is 5h, and after the dropwise adding is finished, continuously carrying out heat preservation reaction for 1 h.
(2) After the reaction is finished, the organic solvent is removed by reduced pressure distillation, then water is added to adjust the solid content to 45 percent, and sodium hydroxide is added to adjust the pH value to 8.
The final polymer weight average molecular weight was determined using GPC to be 46658.
Comparative example 4
(1) 185g of propylene glycol methyl ether was charged into a 1L round-bottom four-neck flask equipped with a stirrer, a condenser and a feed inlet, dissolved with stirring and heated to 110 ℃. An initiator mixture of 30g of acrylic acid, 60g of methyl methacrylate, 60g of diisobutylene, 40g of monomer D1 and 6g a-methyl styrene linear dimer, 0.5g of dibenzoyl peroxide and 15g of propylene glycol methyl ether was prepared. And synchronously dropwise adding the prepared two mixtures into a reactor, starting polymerization reaction, wherein the dropwise adding time is 5h, and after the dropwise adding is finished, continuously carrying out heat preservation reaction for 1 h.
(2) After the reaction is finished, the organic solvent is removed by reduced pressure distillation, then water is added to adjust the solid content to 45 percent, and sodium hydroxide is added to adjust the pH value to 8.
The final polymer weight average molecular weight was measured using GPC to be 58741.
Application test example
To test the dispersant effect of the resulting polymer as a dispersant, the following performance tests were performed:
(1) resin-free inorganic pigment concentrates were prepared according to the formulations in table 1 below. The millbase is dispersed in a shaker for 1 hour by means of glass beads. The millbase is then filtered and stored at room temperature overnight.
TABLE 1 preparation of inorganic pigment concentrates
Name of material
Mass/g
Dispersing agent
0.82
Water (W)
16.5
Titanium white powder
32.5
Mineral oil defoaming agent
0.18
Glass bead
100
Total of
150
Paint A was prepared according to the formulation in Table 2 and the ingredients were mixed in a high shear mixer at 23 ℃ for 5 minutes at 2000rpm to give paint A. The prepared paint A was applied to a black and white cardboard with a film thickness of 250 μm.
TABLE 2 preparation formulation for paint A
Name of material
Mass/g
Inorganic pigment concentrates
21.0
Heavy calcium carbonate
15.4
Talcum powder
4.0
Polyacrylic acid resin
34.3
Defoaming agent
0.4
Propylene glycol
1.0
Butyl diglycol
1.0
Leveling agent
1.5
Water (W)
1.4
Total of
80.0
The following performance tests were performed on the products prepared in tables 1 and 2, and the test results are shown in table 3:
the rheological behaviour of the inorganic millbase is measured using a Brookfield viscometer apparatus at a speed of 20r, a lower viscosity indicating a higher dispersing performance of the dispersant;
the storage stability of the inorganic abrasive is tested by the layering condition in the storage process, and the longer the storage time is, the better the stability of the dispersant is;
the hiding power of paint A is determined according to ISO 6504-1, the higher the contrast ratio, the better the dispersing properties of the dispersant.
TABLE 3 test results for inorganic pigment concentrates and paint A
Examples
Viscosity/cp
Storage stability/d
Hiding contrast ratio/%)
Example 1
87
7
95.2
Example 2
35
7
96.3
Example 3
75
7
95.8
Example 4
50
7
96.1
Comparative example 1
1310
2
87.8
Comparative example 2
1102
2
88.7
Comparative example 3
906
3
91.0
Comparative example 4
635
3
91.6
Blank control
3700
1
87.7
Description of the drawings: table 3 white-in-air control is the performance test result for inorganic pigment concentrate without dispersant addition and paint a prepared by the inorganic pigment concentrate.
(2) Resin-free organic pigment concentrates were prepared according to the formulation in table 4 below. The millbase is dispersed in a shaker for 1 hour by means of glass beads, and then filtered and stored at room temperature overnight.
TABLE 4 preparation of organic pigment concentrates
Name of material
Mass/g
Dispersing agent
2.5
Water (W)
22.2
Phthalocyanine blue
25
Mineral oil defoaming agent
0.2
Glass bead
100
Total of
150
Paint B was prepared from one of the organic pigment concentrates shown in Table 4, according to the formulation shown in Table 5, and the ingredients were mixed in a high shear mixer at 23 ℃ and 2000rpm for 5 minutes.
TABLE 5 preparation formulation for paint B
The following performance tests were performed on the products prepared in tables 4 and 5, and the test results are shown in table 6:
the rheological behaviour of the organic millbase was measured using a Brookfield viscometer apparatus at a rotational speed of 20 r;
the storage stability of the organic millbase is tested by the delamination during storage;
the paint was tested for color development according to the finger research method (GB/T5211.19-1988), with a smaller color difference indicating better color development of the dispersant.
TABLE 6 test results for organic pigment concentrates and paint B
Examples
Viscosity/cp
Storage stability/d
Color difference/. DELTA.E
Example 1
115
6
0.22
Example 2
156
5
0.33
Example 3
132
6
0.28
Example 4
147
6
0.30
Comparative example 1
2300
1
3.87
Comparative example 2
1299
2
2.78
Comparative example 3
927
3
2.16
Comparative example 4
667
3
1.87
Blank control
10221
0
6.3
Description of the drawings: table 6 white-in-air control is the performance test result for inorganic pigment concentrate without dispersant addition and paint B prepared by the inorganic pigment concentrate.
From the test results, the cyclodextrin modified polymer provided by the invention has obvious advantages in dispersing inorganic pigments and fillers or organic pigments and fillers, dispersing performance, suspension stability and color development of colored paint due to special structural design.
The above description is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, several modifications and additions can be made without departing from the method of the present invention, and these modifications and additions should also be regarded as the protection scope of the present invention.
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