WO2014194600A1

WO2014194600A1 - Epoxy microcapsule with polyurea as wall material and preparation method thereof

Info

Publication number: WO2014194600A1
Application number: PCT/CN2013/085220
Authority: WO
Inventors: 朱光明; 邬治平; 汤皎宁; 董必钦; 王险峰; 韩宁旭; 邢峰
Original assignee: 深圳大学
Priority date: 2013-06-07
Filing date: 2013-10-15
Publication date: 2014-12-11
Also published as: CN103331133A; CN103331133B

Abstract

An epoxy microcapsule with polyurea as a wall material, wherein the core material of the microcapsule comprises a liquid epoxy resin, and the wall material of the microcapsule is a crosslinked polyurea prepared by an interface reaction of polyisocyanate and water, the polyisocyanate comprising ternary or more than ternary polyisocyanate. A preparation method of the epoxy microcapsule with polyurea as the wall material, comprising the following steps: dispersing a polyisocyanate and a liquid epoxy resin into water containing a surfactant to obtain a mixed solution; stirring the mixed solution for 0.5-5 hours at a temperature of 25-90°C; filtering, washing and drying, to obtain the epoxy microcapsule with polyurea as the wall material.

Description

Epoxy microcapsule with polyurea as wall material and preparation method thereof

The invention belongs to the technical field of self-healing materials, and particularly relates to an epoxy micro-gel which uses polyurea as a wall material and a preparation method thereof. Background technique

Self-healing materials are pre-embedded in a polymer or concrete matrix. When cracking occurs inside the matrix, the stress concentration at the crack tip releases the repair agent, penetrates the crack under capillary action, and causes a curing reaction to repair the crack. . Epoxy resin has good adhesion, low shrinkage during curing, stable performance, long shelf life, and is the first choice for repairing agents. The method of embedding epoxy resin is to micronize it.

Polyurea is a polymer that is often used as a microcapsule wall material. It is usually formed by polycondensation of a polyisocyanate with a polyamine compound. In the industry, micro-adhesives with polyurea as the wall material have been widely used in the fields of perfumes, insecticides, phase change energy storage, etc. However, in the field of self-healing materials, polyurea is generally not used as the wall material. Epoxy, because the polyamine used in the preparation of polyurea is also a curing agent for epoxy resins. In the process of reacting with polyisocyanates to form polyurea wall materials, polyamines also cure the epoxy and lose the repair function. Moreover, especially linear polyurea, because of its good elasticity, is not suitable for use as a wall material for epoxy microcapsules. The elastomeric wall material is not easily broken, and the coated epoxy resin is difficult to be released under stress and cannot be repaired. Summary of the invention

The technical problem to be solved by the present invention is to overcome the drawbacks of the prior art, and to provide an epoxy microcapsule using polyurea as a wall material and a preparation method thereof.

The present invention is achieved by providing an epoxy microcapsule having polyurea as a wall material, wherein the core material of the microcapsule comprises a liquid epoxy resin, and the wall material is made by interfacial reaction between polyisocyanate and water. Get the deal The polyurea, wherein the polyisocyanate comprises a ternary or trivalent polyisocyanate.

The invention also provides a preparation method of epoxy microcapsules using polyurea as a wall material, which comprises the following steps:

Dispersing a polyisocyanate and a liquid epoxy resin in a surfactant-containing water to obtain a mixed liquid, wherein the polyisocyanate and the liquid epoxy resin are an oil phase, and the surfactant-containing water is an aqueous phase. The polyisocyanate comprises a ternary or trivalent polyisocyanate, the mass ratio of the oil phase to the aqueous phase is 1: 5-10, and the mass ratio of the polyisocyanate to the liquid epoxy resin in the oil phase is 1:1. ~ 2.3, the concentration of the surfactant in the aqueous phase is 0.5 ~ 3%;

The mixture was stirred at 25 to 90 ° C for 0.5 to 5 hours, filtered, washed and dried to obtain an epoxy microcapsule having a polyurea as a wall material.

The wall material of the epoxy microcapsule with polyurea as the wall material provided by the invention is a product obtained by reacting a ternary or trivalent polyisocyanate with water, the crosslinked polyurea, which has a high degree of crosslinking. It has sufficient strength and obvious brittleness to be broken by the stress. The preparation method of the above-mentioned epoxy microcapsules using polyurea as a wall material is a ternary or trivalent polyisocyanate as a raw material, which is miscible with an epoxy resin and dispersed in water to form an emulsion, at a certain temperature and The water undergoes an interfacial reaction to form a polyurea wall. The method not only avoids the problem of reaction between the polyamine monomer and the epoxy resin in the synthesis of the polyurea wall material, but also makes the morphology control of the microcapsules become a single tube because of the reaction through the interface. The obtained microcapsules not only have a high coating ratio, but also have a smooth surface, a uniform wall thickness, and a good sphericity. DRAWINGS

1 is a scanning electron micrograph of an epoxy microcapsule prepared by using the polyurea as a wall material before and after being crushed in the first embodiment of the present invention;

Fig. 2 is a photograph of the epoxy microcapsules prepared by using the polyurea as the wall material before and after the grinding according to the first embodiment of the present invention. detailed description

In order to make the objects, technical solutions and advantages of the present invention more clear, the following specific implementations For example, the present invention will be further described in detail. It is understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

An embodiment of the present invention provides an epoxy microcapsule using polyurea as a wall material, wherein the core material of the microcapsule comprises a liquid epoxy resin, and the wall material is obtained by interfacial reaction between polyisocyanate and water. The crosslinked polyurea, wherein the polyisocyanate comprises a ternary or trivalent polyisocyanate.

Further, the core material further includes at least one of an epoxy resin diluent, a solvent, a coupling agent, a latent curing agent, and a curing accelerator. The polyisocyanate also includes a dibasic isocyanate wherein the molar percentage of the dibasic isocyanate does not exceed 50%.

The embodiment of the invention further provides a preparation method of epoxy microcapsules using polyurea as a wall material, which comprises the following steps:

S01: dispersing a polyisocyanate and a liquid epoxy resin in water containing a surfactant to obtain a mixed liquid, wherein the polyisocyanate and the liquid epoxy resin are oil phases, and the surfactant-containing water is an aqueous phase The polyisocyanate comprises a ternary or trivalent polyisocyanate, the mass ratio of the oil phase to the aqueous phase is 1:5-10, and the mass ratio of the polyisocyanate to the liquid epoxy resin in the oil phase is 1. : 1 - 2.3, the concentration of the surfactant in the aqueous phase is 0.5 ~ 3%;

S02: The mixture is stirred at 25 to 90 ° C for 0.5 to 5 hours, filtered, washed and dried to obtain the epoxy microcapsule having polyurea as a wall material.

Wherein, in step S01, the polyisocyanate is 4,4',4"-triphenyldecane triisocyanate (TTI), tris(4-isocyanatephenyl) thiophosphate (ΤΡΉ), tetraisocyanate (2) , 2'-dimercapto-3,3',5,5'-triphenyldecane tetraisocyanate, DTTI, or triphenyldecane-2,2'-dimercapto-3,3' , 5,5'-tetraisocyanate, at least one of TPMDMTI poly-mercapto polyphenyl polyisocyanate (PAPI). The polyisocyanate may further comprise a diisocyanate, and the diisocyanate refers to a terpene diisocyanate. (TDI), 4,4'-diphenyldecane diisocyanate (MDI), 1,5-naphthalene diisocyanate (NDI), hexamethylene diisocyanate (HDI), ethylbenzene diisocyanate (EDI), 4 , 4'-dicyclohexene decane diisocyanate (H ₁₂ MDI ), 4,6-diphenylene diisocyanate (XDI), isophorone diisocyanate (IPDI), p-phenylene diisocyanate (PPDI), ring Hexyl diisocyanate (THDI), 3,3'-dimercaptobiphenyl-4,4' At least one of isocyanate (TODI) and 3,3'-dimercapto-4,4'-diphenyldecane diisocyanate. The diisocyanate is added in an amount not exceeding 50% by mole of the polyisocyanate.

The liquid epoxy resin is insoluble in water and is in a liquid state at room temperature. At least one of an epoxy resin diluent, a solvent, a coupling agent, and a latent curing agent may be added to the liquid epoxy resin. Diluents and solvents improve epoxy fluidity, coupling agents enhance adhesion to the substrate, latent curing agents and curing accelerators cure the epoxy, and other additives to enhance epoxy repair. The additives are all present in the oil phase, are insoluble in water, and do not react with water.

The surfactant is SMA (styrene-maleic anhydride block copolymer), gum arabic, polyoxyethylene polyoxypropylene, ethylenediamine polyoxyethylene-polyoxypropylene block polyether, heteroblock type poly Ether, Tween, span, PVA (polyvinyl alcohol), PEG (polyethylene glycol), alkyl phenol ethoxylate, fatty alcohol ethoxylate, APG (alkyl polyglycoside, alkane At least one of the glucosides.

In step S02, the mixed solution is stirred at a temperature of 25 to 90 ° C for 0.5 to 5 hours, a stirring rate of 600 to 1000 rpm, and a reaction time of preferably 0.5 to 3 hours. The formation of the epoxy microcapsules in the step S02 with polyurea as the wall material is due to the fact that the isocyanate reacts easily with water, and is first added to form aminoguanic acid, which is then decomposed into amines and carbon dioxide, which is generated in situ. The amine is then reacted with isocyanate to form a substituted urea. The process is as follows:

R-NCO+H ₂ 0 R-NCOOH R-NH ₂ +C0 ₂ ( i )

R-NH ₂ +R-NCO R-NHCON-R ( ₂ ) Since the reaction ( 2 ) is fast, the amine R-NH ₂ produced by the reaction (1) is immediately consumed by the reaction ( 2 ), so the whole will not There is a residual amine R-NH _{2 that} has a chance to cure with the epoxy resin. Obviously, if the isocyanate in the reaction formulas (1) and (2) is a polyisocyanate, the reaction will eventually obtain a polyurea, and it is not difficult to understand that the product of the reaction of the diisocyanate with water is a polyurea having a linear structure, a triisocyanate or a trisole. The product reaction of the above polyisocyanate with water will be a crosslinked polyurea.

In order to shorten the reaction time or lower the reaction temperature, a catalyst may be added to the mixed solution. The reminder The agent is an organometallic catalyst, specifically stannous octoate, dibutyltin dilaurate (DBTDL), lead isooctanoate, lead octoate, zinc isooctanoate, zinc octoate, mercury octoate, phenylmercuric acetate, mercury naphthalate And at least one of phenylmercuric propionate, phenylmercuric acid oleate, lead oleate, lead phenyl phthalate, iron acetylacetonate, zinc naphthenate, cobalt naphthenate, and oleic acid. Preferably, the catalyst is DBTDL. The catalyst is added in an amount of 0.1 to 1% by mass of the oil phase.

The preparation method of the epoxy microcapsules using polyurea as the wall material is compared with the method of synthesizing the microcapsules which are synthesized by in-situ polymerization, such as urea-formaldehyde, melamine and other amine-based resins as wall materials. Urea is a wall material epoxy micro-adhesive preparation method. The process is simple, the product shape is controllable, suitable for large-scale production, and has high practical value. The preparation of the above epoxy microcapsules using polyurea as a wall material is exemplified below by way of specific examples. Embodiment 1:

8 g of TTI (molecular weight 367), 10 g of epoxy E-51, and 1.5 g of acetone were uniformly mixed, and added to a three-necked flask containing 100 g of a 1% PVA solution, and emulsified at 60 ° C and 1000 rpm for 30 min. The rotation speed was reduced to 400 rpm, 0.03 g of catalyst dibutyltin dilaurate (DBTDL) was added, and the reaction was kept at 60 ° C for 3 h. The reaction solution was filtered, washed with distilled water, filtered, and repeated three times, and then dried at 45 ° C for 12 h to obtain a polyurethane-coated epoxy microcapsule white powder. SEM observation confirmed that microcapsules with a particle size distribution of 20 - 70 μm and a wall thickness of 800 to 1000 nm were obtained, as shown in Fig. 1. Fourier transform infrared spectroscopy (FTIR) analysis showed a strong urea C=0-based absorption peak at 1640 cm- ¹ , confirming that the wall material was polyurea. After the microcapsules were ground with a mortar and observed with an optical microscope, a sticky liquid epoxy was observed, as shown in FIG. Embodiment 2:

Weigh 8g DTTI (molecular weight 436), add a small amount of ethyl acetate, prepare a solution, mix well with 10g epoxy E-51, and add it to a three-necked flask containing 100g of 1% SMA (Screpset 520) solution at 15°. C, lOOOrpm emulsified lOmin, reduce the rotation speed to 400rpm, mix evenly and add 0.03g The catalyst DBTDL was heated to 60 ° C and the reaction was kept for 3 h. The reaction solution was filtered, washed with distilled water, filtered, and repeated three times, and then dried at 45 ° C for 12 hours to obtain a polyurethane-coated epoxy microcapsule white powder. SEM observation showed that the particle size distribution was 20 ~ 80μιη, and the wall thickness was 800 ~ 900nm. The FTIR spectrum confirmed that the wall material was polyurea. The microcapsules after the grinding were observed by an optical microscope, and the sticky liquid epoxy was observed to flow out. Embodiment 3:

Weigh 4g MDI (molecular weight 250), 4g DTTI (molecular weight 436, add a small amount of ethyl acetate to form a solution), mix well with 10 epoxy g E-51, and add to a three-necked flask containing 100g of 1% SMA solution. Emulsified at 15 ° C, 1000 rpm for 10 min. The rotation speed was reduced to 400 rpm, the temperature was raised to 80 ° C, and the reaction was kept for 5 hours. The reaction solution was filtered, washed with distilled water, filtered, and repeated three times, and then dried at 45 ° C for 12 hours to obtain a polyurethane-coated epoxy microcapsule white powder. SEM observation showed that the particle size distribution was 25 ~ 80μιη, and the wall thickness was 800 ~ 900nm. The FTIR spectrum confirmed that the wall material was polyurea. The optical microscope was used to observe the mashed enamel, and the sticky liquid epoxy was seen to flow out. The above is only the preferred embodiment of the present invention, and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection of the present invention. Within the scope.

Claims

claims

1. An epoxy microcapsule with polyurea as the wall material, characterized in that the core material of the microcapsule includes liquid epoxy resin, and the wall material is made by interfacial reaction between polyisocyanate and water. Cross-linked polyurea, wherein the polyisocyanate includes a three- or more-valent polyisocyanate.

2. The epoxy microcapsule with polyurea as the wall material according to claim 1, characterized in that the core material also includes an epoxy resin diluent, a solvent, a coupling agent, a latent curing agent, and a curing agent. at least one of the accelerators.

3. The epoxy microcapsule with polyurea as the wall material according to claim 1, characterized in that the polyisocyanate also includes dibasic isocyanate.

4. A method for preparing an epoxy capsule with polyurea as the wall material, which includes the following steps: dispersing polyisocyanate and liquid epoxy resin in water containing surfactant to obtain a mixed liquid, wherein, The polyisocyanate and liquid epoxy resin are oil phases, the water containing surfactant is a water phase, the polyisocyanates include trivalent or more trivalent polyisocyanates, and the mass ratio of the oil phase to the water phase is 1: 5 ~ 10, the mass ratio of polyisocyanate to liquid epoxy resin in the oil phase is 1: 1 ~ 2.3, and the concentration of surfactant in the water phase is 0.5 ~ 3%;

The mixture is stirred at 25 to 90°C for 0.5 to 5 hours, filtered, washed and dried to obtain the epoxy microcapsule with polyurea as the wall material.

5. The method for preparing epoxy microcapsules using polyurea as wall material according to claim 4, characterized in that the polyisocyanate further includes dibasic isocyanate.

6. The preparation method of epoxy microcapsules using polyurea as wall material as claimed in claim 4, characterized in that, the polyisocyanate is 4,4',4"-triphenylmethane triisocyanate, At least one of tris(4-isocyanatophenyl) thiocyanate, tetraisocyanate, and polymethylene polyphenyl polyisocyanate.

7. The method for preparing epoxy microcapsules using polyurea as wall material according to claim 4, characterized in that In, the surfactant is styrene-maleic anhydride block copolymer, gum arabic, polyoxyethylene polyoxypropylene, ethylenediamine polyoxyethylene-polyoxypropylene block polyether, hetero block polyether , Tween, spanane, at least one of polyvinyl alcohol, polyethylene glycol, alkylphenol polyoxyethylene ether, fatty alcohol polyoxyethylene ether, and alkyl glycoside.

8. The method for preparing epoxy microcapsules with polyurea as the wall material according to claim 4, wherein the oil phase also includes an epoxy resin diluent, a solvent, a coupling agent, a latent type At least one of a curing agent and a curing accelerator.

9. The method for preparing epoxy microcapsules with polyurea as the wall material according to claim 4, characterized in that a catalyst is added to the mixed liquid, and the catalyst is an organic metal catalyst.

10. The method for preparing epoxy microcapsules with polyurea as the wall material according to claim 4 or 9, characterized in that the organometallic catalyst is stannous octoate, dibutyltin dilaurate, isobutyltin dilaurate, or stannous octoate. Lead octoate, lead octoate, zinc isooctanoate, zinc octoate, mercury octoate, phenylmercuric acetate, mercury naphthalate, phenylmercuric propionate, phenylmercuric oleate, lead oleate, lead phthalate, iron acetylacetonate, At least one of zinc naphthenate, cobalt naphthenate, and potassium oleate.