CN108579634B - A kind of preparation method of hydrophobic amine capsule - Google Patents

Abstract

The invention provides a preparation method of a hydrophobic amine capsule, wherein an oil-in-water system is constructed by using a highly reactive hydrophobic amine as a core material to encapsulate the capsule. First, a protective film is formed on the surface of the amine droplets by adding an aqueous curing agent dropwise, and then a wall material prepolymer is added to adjust the environment of the system for curing reaction to further coat the core material. The invention aims to carry out stability protection for the highly active amine core material, so as to reduce the reaction consumption with the wall material. The research method has the advantages of simple synthesis process, high encapsulation efficiency, low equipment requirements, easy control of reaction conditions, and is a green and energy-saving production process. The prepared amine capsules can be used in the fields of material bonding and repair, as well as paints and coatings.

Description

A kind of preparation method of hydrophobic amine capsule

technical field

The invention relates to a preparation method of an amine capsule, in particular to a preparation method of a highly reactive hydrophobic amine capsule with a controllable particle size.

Background technique

Encapsulation refers to the use of film-forming technology to coat solids, liquids or gases into micro-containers with specific geometric structures, so as to protect or control the release of core substances. Encapsulation technology is widely used in hygiene, food, medicine, coatings , paints, adhesives and other fields.

Amine is a highly reactive substance containing active hydrogen, which can undergo nucleophilic reaction with epoxy resin, isocyanate, acid anhydride, haloalkane, acid chloride, etc., and can also be used as a catalyst for epoxy-thiol, isocyanate-thiol and other reaction systems , it is widely used in actual production, so it is of great significance to use amine as the capsule core for encapsulation.

The patent CN105833811A "a double microcapsule self-healing epoxy coating and its preparation method" involves the encapsulation of amines, and the tetraethylene pentamine is coated by the Pickering emulsion drop template method using interfacial polymerization. Tetraethylenepentamine is a toxic water-soluble amine, and xylene is needed to wash the capsules in a water-in-oil system. The method is complicated in operation and harsh in reaction conditions, and at the same time, the reaction process needs to use toxic solvents, which will cause great harm to the environment, and the separation and purification of the final product is difficult, which is not suitable for large-scale industrial production. Therefore, choosing a hydrophobic amine for encapsulation has great research significance and value.

In the patent CN107088389A "a two-component capsule and its preparation method", oil-soluble amine monomer or oligomer is selected as the capsule core material. When the material is used, the high reactivity of the amine will cause a side reaction with the capsule wall to consume a part of the core material, thereby destroying the stability of the emulsion. controlled hydrophobic amine capsules.

SUMMARY OF THE INVENTION

In order to solve the above-mentioned technical problems, the present invention provides a preparation method of hydrophobic amine capsules. During the encapsulation of hydrophobic amines, an aqueous curing agent is added to react with the amine on the surface of the droplets to form a protective layer, thereby increasing the amount of emulsion droplets. The stability can finally improve the consumption of the highly active amine core material by the wall material, and obtain the hydrophobic amine microcapsules with controllable particle size.

The concrete steps that the present invention prepares two-component capsules are as follows:

(1) by mass, adding 100 parts of hydrophobic amine monomer or oligomer oil phase substance to 200～3000 parts of emulsifier aqueous solution with a concentration of 0.1～50wt%, shearing and emulsification to obtain an oil-in-water emulsion;

(2) the oil-in-water emulsion obtained in step (1) is transferred to a three-necked flask and stirred, and a small amount of aqueous curing agent solution is slowly added dropwise to the flask at a certain speed for a period of time;

(3) The wall material solution is added to the flask at a certain speed, after the dropwise addition is completed, the reaction is kept for a period of time, and then the temperature is increased and matured to obtain a hydrophobic amine capsule with a core-shell structure, and the suspension is filtered, washed and dried. can be used for further applications.

The hydrophobic amine monomer or oligomer is at least one of the group consisting of polyaspartate, polyetheramine, octadecenylamine, 4,4'-dioctyldiphenylamine and naphthylamine .

The water-based curing agent is water-based epoxy resin and water-based isocyanate capable of nucleophilic reaction with amino groups, including bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, toluene diisocyanate, Any one of diphenylmethane-4,4'-diisocyanate, 1,6-hexamethylene diisocyanate, isophorone diisocyanate, trimethylhexane diisocyanate or one of its oligomers after Aqueous dispersion system obtained.

The wall material is phenolic resin, urea-formaldehyde resin, methyl etherified melamine formaldehyde resin, butyl etherified melamine formaldehyde resin, polymethyl methacrylate, polyurethane, chitosan, sodium alginate, cellulose acetate, gelatin, At least one of the group consisting of gum arabic.

Described emulsifier is polyvinyl alcohol, polyvinylpyrrolidone, sorbitan oleate, emulsifier OP10, fatty alcohol polyoxyethylene ether sodium sulfate, styrene maleic anhydride copolymer, fatty alcohol polyoxyethylene ether, Turkey Red oil, sodium alkyl benzene sulfonate, sodium dodecyl sulfonate, propylene alginate, polyoxyethylene sorbitan monooleate, sodium alkyl sulfate, or the group consisting of pull-off powder at least one. The further applications include adhesives, paints, and coatings, including: any one of anti-corrosion coatings, electrical insulating coatings, floor coatings, electronic coatings, architectural coatings, special coatings, decorative coatings, automotive primers, and phosphating primers .

The dropping rate of the aqueous curing agent solution is 0.1 to 15 mL/h.

In the process of encapsulation of the hydrophobic amine, an aqueous curing agent is added to react with the amine on the surface of the droplet to form a protective layer, so as to increase the stability of the emulsion droplet, and finally can improve the consumption of the wall material to the high-activity amine core material. The hydrophobic amine microcapsules with controllable particle size are obtained. The encapsulation process adopts an oil-in-water system, the preparation process is simple, the energy consumption is low, and the encapsulation efficiency is high. It is a green and energy-saving production process and is suitable for large-scale production.

Description of drawings

Fig. 1 is the topography (scanning electron micrograph) of the amine capsules prepared in Example 1

Fig. 2 is the topography (scanning electron micrograph) of the amine capsules prepared in Example 2

Detailed ways

The method described in the present invention is further illustrated by specific examples below, but it is not meant that the present invention is limited to these examples.

Example 1:

A preparation method of hydrophobic amine capsule, comprising the steps:

(1) Weigh 40g of polyaspartic acid ester resin F220, add it to an aqueous solution containing 300g of styrene maleic anhydride copolymer sodium salt concentration of 15wt%, mix with magnetic stirring under 40°C, and use 3000rpm rotating speed to carry out High-speed shear emulsification was performed for 15 min to obtain a uniform oil-in-water emulsion.

(2) transfer the emulsion to the three-necked flask, stir at a speed of 500rpm under 60°C, drop 20g of melamine-formaldehyde resin into the three-necked flask at a speed of 10mL/h, keep the temperature for a period of time after the dripping is completed, and then heat up To 70 ℃ ripening.

(3) performing suction filtration, washing and drying on the capsule suspension to finally obtain an amino resin-coated polyaspartate capsule having a core-shell structure.

The morphology of the two-component capsules prepared in this example is shown in Figure 1. It can be seen from the figure that the particle sizes of the capsules prepared in this example are all less than 1 μm, which is inconsistent with the particle size of the emulsion droplets obtained after shear emulsification.

Example 2:

A preparation method of hydrophobic amine capsule, comprising the steps:

(1) Weigh 40g of polyaspartic acid ester resin F220, add it to an aqueous solution containing 300g of styrene maleic anhydride copolymer sodium salt concentration of 15wt%, mix with magnetic stirring under 40°C, and use 3000rpm rotating speed to carry out High-speed shear emulsification was performed for 15 min to obtain a uniform oil-in-water emulsion.

(2) Transfer the emulsion to the three-necked flask, stir at a speed of 500rpm under 40°C, dissolve 5g of water-based isocyanate curing agent in water and dropwise add it to the three-necked flask at a speed of 2mL/h, and keep it for a period of time after the dripping is completed. time.

(3) Slowly heat up to 60°C, drop 20g of melamine-formaldehyde resin into the three-necked flask at a rate of 10mL/h, keep the temperature for a period of time after the dropwise addition, and then heat up to 70°C for aging.

(4) The capsule suspension is subjected to suction filtration, washing and drying to finally obtain an amino resin-coated polyaspartate capsule having a core-shell structure.

The morphology of the two-component capsules prepared in this example is shown in Figure 2. As can be seen from the figure, the capsules prepared in this example are in the shape of regular spheres, and the particle size is about 1 μm, which is similar to the one obtained after shear emulsification. The size of the milk droplets is consistent.

Example 3:

(1) take by weighing 40g of octadecenylamine, add in the aqueous solution containing 300g of emulsifier OP10 concentration of 15wt%, mix uniformly with magnetic stirring under 40 ℃ conditions, use 4000rpm rotating speed to carry out high-speed shear emulsification for 15min, obtain uniform water Oil-in-Lotion.

(2) Transfer the emulsion to the three-necked flask, stir at a speed of 500rpm under 40°C, dissolve 5g of water-based isocyanate curing agent in water and dropwise add it to the three-necked flask at a speed of 2mL/h, and keep it for a period of time after the dripping is completed. time.

(3) Slowly heat up to 60°C, add 20 g of butyl etherified amino resin dropwise to the three-necked flask at a rate of 10 mL/h, keep the temperature for a period of time after the dropwise addition, and then heat up to 70°C for aging.

(4) The capsule suspension is subjected to suction filtration, washing and drying to finally obtain a butyl etherified amino resin-coated octadecenamine capsule having a core-shell structure.

Example 4:

(1) Weigh 40g of polyetheramine, add it to the aqueous solution containing 300g of sodium dodecyl sulfonate concentration of 15wt%, mix uniformly with magnetic stirring under the condition of 40°C, use 5000rpm rotating speed to carry out high-speed shear emulsification for 15min, obtain Homogeneous oil-in-water emulsion.

(2) Transfer the emulsion to a three-necked flask, stir at a speed of 500rpm under 40°C, dissolve 5g of water-based epoxy resin in water and dropwise add it to the three-necked flask at a speed of 2mL/h, and keep it for a period of time after the dripping is completed. time.

(3) Slowly heat up to 60°C, drop 20g of urea-formaldehyde resin into the three-necked flask at a rate of 10mL/h, keep the temperature for a period of time after the dropwise addition, and then heat up to 70°C for aging.

(4) The capsule suspension is subjected to suction filtration, washing, and drying to finally obtain a urea-formaldehyde resin-coated polyetheramine capsule having a core-shell structure.

Claims (7)

1. A preparation method of hydrophobic amine capsules comprises the following steps:

(1) adding 100 parts by mass of hydrophobic amine monomer or oligomer oil phase substances into 200-3000 parts by mass of 0.1-50 wt% emulsifier aqueous solution, and shearing and emulsifying to obtain an oil-in-water emulsion;

(2) transferring the oil-in-water emulsion obtained in the step (1) into a three-neck flask, stirring, slowly dripping a small amount of aqueous curing agent solution into the flask at a certain speed, and keeping for a period of time;

(3) and adding the wall material solution into a flask at a certain speed, carrying out heat preservation reaction for a period of time after the dropwise addition is finished, heating and curing to obtain the hydrophobic amine capsule with the core-shell structure, and carrying out suction filtration, washing and drying on the suspension to obtain the hydrophobic amine capsule for further application.

2. The method of claim 1, wherein: the hydrophobic amine monomer or oligomer is at least one of the group consisting of polyaspartic acid ester, polyether amine, octadecenylamine, 4, 4' -dioctyl diphenylamine and naphthylamine.

3. The method of claim 1, wherein: the waterborne curing agent is waterborne epoxy resin and waterborne isocyanate which can generate nucleophilic reaction with amino, and comprises a dispersion system obtained by carrying out waterborne treatment on any one of bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, toluene diisocyanate, diphenylmethane-4, 4' -diisocyanate, 1, 6-hexamethylene diisocyanate, isophorone diisocyanate and trimethylhexane diisocyanate or one of oligomers thereof.

4. The method of claim 1, wherein: the wall material is at least one of the group consisting of phenolic resin, urea resin, methyl etherified melamine formaldehyde resin, butyl etherified melamine formaldehyde resin, polymethyl methacrylate, polyurethane, chitosan, sodium alginate, cellulose acetate, gelatin and Arabic gum.

5. The method of claim 1, wherein: the emulsifier is at least one of polyvinyl alcohol, polyvinylpyrrolidone, sorbitan oleate, emulsifier OP10, fatty alcohol-polyoxyethylene ether sodium sulfate, styrene maleic anhydride copolymer, fatty alcohol-polyoxyethylene ether, Turkey red oil, sodium alkyl benzene sulfonate, sodium dodecyl sulfonate, propylene glycol alginate, polyoxyethylene sorbitan monooleate, sodium alkyl sulfate or nekal.

6. The method of claim 1, wherein: further applications include adhesives, paints, coatings, including: any one of anticorrosive paint, electric insulating paint, floor paint, electronic paint, building paint, special paint, decorative paint, automobile primer and phosphatized primer.

7. The method of claim 1, wherein: the dropping rate of the aqueous curing agent solution is 0.1-15 mL/h.

Images