CN115926117A - Curing agent microcapsule and preparation method and application thereof - Google Patents
Curing agent microcapsule and preparation method and application thereof Download PDFInfo
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- CN115926117A CN115926117A CN202211681101.0A CN202211681101A CN115926117A CN 115926117 A CN115926117 A CN 115926117A CN 202211681101 A CN202211681101 A CN 202211681101A CN 115926117 A CN115926117 A CN 115926117A
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- 239000003094 microcapsule Substances 0.000 title claims abstract description 116
- 238000002360 preparation method Methods 0.000 title claims abstract description 37
- 239000000463 material Substances 0.000 claims abstract description 39
- 239000004005 microsphere Substances 0.000 claims abstract description 39
- 239000002994 raw material Substances 0.000 claims abstract description 35
- 239000002775 capsule Substances 0.000 claims abstract description 30
- 229920000768 polyamine Polymers 0.000 claims abstract description 16
- 229920000058 polyacrylate Polymers 0.000 claims abstract description 14
- 239000004793 Polystyrene Substances 0.000 claims abstract description 11
- 229920002223 polystyrene Polymers 0.000 claims abstract description 11
- 229920002554 vinyl polymer Polymers 0.000 claims abstract description 11
- -1 alicyclic amine Chemical class 0.000 claims abstract description 9
- 125000003118 aryl group Chemical group 0.000 claims abstract description 8
- ZBCBWPMODOFKDW-UHFFFAOYSA-N diethanolamine Chemical compound OCCNCCO ZBCBWPMODOFKDW-UHFFFAOYSA-N 0.000 claims abstract description 8
- 150000003839 salts Chemical class 0.000 claims abstract description 8
- 239000012071 phase Substances 0.000 claims description 45
- 238000000034 method Methods 0.000 claims description 41
- YMWUJEATGCHHMB-UHFFFAOYSA-N Dichloromethane Chemical compound ClCCl YMWUJEATGCHHMB-UHFFFAOYSA-N 0.000 claims description 39
- 239000002904 solvent Substances 0.000 claims description 23
- 238000006243 chemical reaction Methods 0.000 claims description 22
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 18
- 239000000725 suspension Substances 0.000 claims description 15
- 239000003995 emulsifying agent Substances 0.000 claims description 13
- 239000007864 aqueous solution Substances 0.000 claims description 12
- 239000004372 Polyvinyl alcohol Substances 0.000 claims description 8
- 238000004945 emulsification Methods 0.000 claims description 8
- 229920002451 polyvinyl alcohol Polymers 0.000 claims description 8
- 229920006332 epoxy adhesive Polymers 0.000 claims description 7
- 239000012265 solid product Substances 0.000 claims description 7
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 claims description 6
- 239000008346 aqueous phase Substances 0.000 claims description 6
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- 238000006116 polymerization reaction Methods 0.000 description 6
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- RNLHGQLZWXBQNY-UHFFFAOYSA-N 3-(aminomethyl)-3,5,5-trimethylcyclohexan-1-amine Chemical compound CC1(C)CC(N)CC(C)(CN)C1 RNLHGQLZWXBQNY-UHFFFAOYSA-N 0.000 description 2
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Abstract
The invention provides a curing agent microcapsule and a preparation method and application thereof. The curing agent microcapsule of the invention can realize real physical isolation effect by utilizing an encapsulation technology, and blocks the interaction of the curing agent and the matrix epoxy resin, thereby having longer storage life. The curing agent microcapsule takes at least one of polyvinyl microspheres, polystyrene microspheres and polyacrylate microspheres as a wall material raw material and at least one of aromatic polyamine, polyamine salt, alicyclic amine and aliphatic amine as a capsule core raw material, and has the characteristics of high coating rate, stability, difficult release and convenient storage and transportation. The invention also provides a preparation method and application of the curing agent microcapsule.
Description
Technical Field
The invention belongs to the technical field of epoxy resin, and particularly relates to a curing agent microcapsule as well as a preparation method and application thereof.
Background
Epoxy resin is a thermosetting polymer material with good adhesion, insulation and corrosion resistance. The resin is widely applied to the fields of buildings, machinery, electronics and electrics, aerospace and the like as a resin matrix of adhesives, coatings, composite materials and the like. When the epoxy resin is used, a curing agent is added, and curing reaction is carried out under certain conditions to generate a product with a three-dimensional net structure, so that various excellent performances can be shown, and the epoxy resin becomes an epoxy material with real use value.
The epoxy resin systems generally used are two-component, i.e. the epoxy resin is packaged separately from the curing agent. When in use, the epoxy resin and the curing agent are uniformly mixed according to a certain proportion, the problems of operation and environmental protection are brought because the bi-component adhesive needs to be subpackaged, stored and transported, and important properties such as the bonding strength of a product are easy to fluctuate because of metering error and nonuniform mixing during mixing preparation. After the glue solution is prepared, the viscosity of the system is continuously increased along with the progress of chemical reaction, so that the application life is limited, the glue solution is particularly not suitable for a new process of automatic bonding, and the scrapping is easy to generate.
In the related art, latent curing agents are mainly achieved by temporarily blocking or inactivating reactive groups and structures in some curing agents having high reactivity and poor storage stability. However, the curing agent directly contacts with the matrix epoxy resin, and the single-component epoxy adhesive prepared from the latent curing agent generally undergoes a physicochemical reaction in a storage process, so that the storage period (pot life) of the single-component epoxy adhesive is reduced, and further the exertion of the effectiveness of the adhesive is influenced.
For latent curing agents, curing temperature and pot life are generally contradictory: namely, the epoxy adhesive with long storage life at low temperature has higher curing temperature or longer curing time. When a curing agent with a low curing temperature or a short curing time is selected, the index of the low-temperature storage life of the epoxy adhesive prepared from the curing agent is greatly reduced. And the traditional latent curing agent has more requirements on temperature conditions, so that the use scene of the curing agent is greatly limited.
Therefore, there is still a need to develop a new curing agent.
Disclosure of Invention
The present invention is directed to solving at least one of the above problems in the prior art. Therefore, the invention provides a curing agent microcapsule which has an adjustable porous micro-nano structure shell, is high in coating rate, stable, difficult to release and convenient to store and transport, and can realize softening and deblocking of a microcapsule shell material only by heating to a specific temperature during use, so that an adhesive can achieve the purpose of rapid curing.
The invention also provides a method for preparing the curing agent microcapsule.
The invention also provides the application of the curing agent microcapsule in preparing epoxy resin adhesives.
The invention provides a curing agent microcapsule, which comprises a capsule core and a wall material wrapping the capsule core, wherein a preparation raw material of the capsule core comprises at least one of aromatic polyamine, polyamine salt, alicyclic amine and aliphatic amine, a preparation raw material of the wall material comprises at least one of polyvinyl microspheres, polystyrene microspheres and polyacrylate microspheres, and the wall material has a micro-nano porous structure.
The invention relates to one of the technical schemes of the curing agent microcapsule, which at least has the following beneficial effects:
compared with the common traditional latent curing agent, the curing agent microcapsule of the invention can realize the real physical isolation effect by using the encapsulation technology, and can block the interaction of the curing agent and the matrix epoxy resin, thereby having longer storage life.
The curing agent microcapsule takes at least one of polyvinyl microspheres, polystyrene microspheres and polyacrylate microspheres as a wall material and at least one of aromatic polyamine, polyamine salt, alicyclic amine and aliphatic amine as a capsule core material, and has the characteristics of high coating rate, stability, difficult release and convenient storage and transportation.
The curing agent microcapsule disclosed by the invention has a porous micro-nano shell structure, so that the curing agent can be more stably and uniformly dispersed in the epoxy resin single-component adhesive. Specifically, the porous micro-nano shell structure refers to that nano-scale holes and micron-scale holes are distributed on the outer surface of a microcapsule wall material.
Compared with the traditional latent curing agent, the curing agent microcapsule provided by the invention really realizes the 'latent' of the curing agent in the adhesive, realizes physical isolation due to microcapsule coating, does not need to additionally add an inhibitor and a polymerization inhibitor, and can stably exist in the adhesive. When the curing agent microcapsule is used, the curing agent microcapsule is cracked and deblocked through temperature rise or external force, so that the rapid curing of the adhesive can be realized.
According to some embodiments of the invention, the mass ratio of the raw materials for preparing the wall material to the raw materials for preparing the capsule core is 1 to 5:3.
According to some embodiments of the invention, the mass ratio of the raw material for preparing the wall material to the raw material for preparing the capsule core is 1 to 3:3.
According to some embodiments of the invention, the raw material for the preparation of the caplet comprises H 12 MDA。
A second aspect of the present invention provides a method of preparing a curing agent microcapsule, comprising the steps of:
s1: dispersing the aqueous solution of the emulsifier to obtain a water phase;
s2: adding a wall material preparation raw material and a capsule core preparation raw material into a volatile solvent, and dispersing to obtain an oil phase;
s3: adding the oil phase into the water phase, carrying out an emulsification reaction at room temperature, and then raising the temperature until the volatile solvent volatilizes to obtain a suspension;
s4: and centrifuging the suspension to obtain a solid product, namely the curing agent microcapsule.
There are three main methods for preparing microcapsule curing agents. One is an interfacial polymerization method, which has some insurmountable disadvantages such as long reaction time, complicated reaction equipment, and high preparation cost of required materials. The other method is an in-situ polymerization method, which is greatly influenced by an emulsifier, reaction temperature, pH value, stirring speed and the like, and most shell materials of the method are synthetic resin, and formaldehyde is needed, so that the method is not environment-friendly. The third method is a solvent evaporation method, compared with other methods, the microcapsule curing agent prepared by the solvent evaporation method does not need to adjust the pH value, heat and cool, and does not need special reaction reagents, and the method has the advantages of simple equipment, low cost, easy popularization and suitability for large-scale industrial production. However, the thermal stability is poor and the core material content is low, thus affecting the storage life of the curing agent and the performance of the cured colloid.
Aiming at the defects of the prior art, the technical scheme for preparing the curing agent microcapsule provides a method for preparing the curing agent microcapsule which has the advantages of adjustable porous micro-nano structure, high core material content and good stability.
The invention relates to a technical scheme for preparing curing agent microcapsules, which at least has the following beneficial effects:
the preparation method of the invention comprises the steps of firstly dispersing the aqueous solution of the emulsifier to obtain a water phase; adding a wall material preparation raw material and a capsule core preparation raw material into a volatile solvent, and dispersing to obtain an oil phase; then adding the oil phase into the water phase, carrying out an emulsification reaction at room temperature, and raising the temperature until the volatile solvent volatilizes to obtain a suspension; and finally, centrifuging the suspension to obtain a solid product, namely the curing agent microcapsule. According to the method, the adjustment of the wall material micro-nano porous structure is realized by adjusting the ratio of the core material to the wall material (core-wall ratio). According to actual needs, curing agent microcapsules with different micro-nano porous structures can be prepared.
According to some embodiments of the invention, the emulsifier is present in the aqueous solution in an amount of 0.1% to 2% by weight.
According to some embodiments of the invention, the emulsifier comprises at least one of gum arabic, gelatin, and polyvinyl alcohol.
According to some embodiments of the invention, in step S1, the dispersing is performed by mechanical stirring.
According to some embodiments of the invention, the mechanical agitation is at a speed of from 300rpm to 450rpm.
According to some embodiments of the invention, the time of the mechanical stirring is between 10min and 30min.
According to some embodiments of the invention, in the step S2, the mass volume ratio of the raw material for preparing the wall material to the volatile solvent is 1g to 5g.
According to some embodiments of the invention, in step S2, the mass-to-volume ratio of the raw material for preparing the caplet to the volatile solvent is 1g to 5 g.
According to some embodiments of the invention, in step S2, the dispersing is performed in an ultrasound device.
According to some embodiments of the invention, in step S2, the volatile solvent comprises at least one of dichloromethane, chloroform and acetone.
According to some embodiments of the invention, in step S3, the volume ratio of the oil phase to the aqueous phase is 1:2 to 10.
According to some embodiments of the invention, step S3, the oil phase is added to the aqueous phase, requiring a slow addition.
According to some embodiments of the present invention, the oil phase may be added dropwise to the aqueous phase within 5min to 10min in step S3.
According to some embodiments of the invention, in step S3, the time of the emulsification reaction at room temperature is: stirring and emulsifying for 10-30 min, and then stirring and reacting for 1-2 h at room temperature (normal temperature).
According to some embodiments of the invention, in step S3, after the emulsion reaction at room temperature, the temperature is raised to 35 ℃ to 45 ℃ and stirred for 3h to 5h to volatilize the volatile solvent.
According to some embodiments of the invention, in step S3, after the emulsion reaction at room temperature, the temperature is raised to 38 ℃ to 40 ℃, and the stirring is carried out for 3h to 5h, so as to volatilize the volatile solvent.
According to some embodiments of the invention, the method further comprises washing and drying the solid product in step S4.
The third aspect of the present invention provides the use of curing agent microcapsules in the preparation of epoxy adhesives.
The invention relates to a technical scheme of the application of curing agent microcapsules in preparing epoxy resin adhesives, which at least has the following beneficial effects:
when the epoxy resin adhesive is prepared, the curing agent microcapsule is used, so that the epoxy resin adhesive has all the technical effects of the curing agent microcapsule. Specifically, the method comprises the following steps:
compared with the common traditional latent curing agent, the curing agent microcapsule provided by the invention can realize a real physical isolation effect by using an encapsulation technology, and the interaction between the curing agent and the matrix epoxy resin is blocked, so that the storage life of the epoxy resin adhesive is longer.
When the epoxy resin adhesive is prepared, the curing agent microcapsule takes at least one of polyvinyl microspheres, polystyrene microspheres and polyacrylate microspheres as a wall material and at least one of aromatic polyamine, polyamine salt, alicyclic amine and aliphatic amine as a capsule core material, so that the curing agent microcapsule has the characteristics of high coating rate, stability, difficult release and convenience in storage and transportation.
When the epoxy resin adhesive is prepared, the curing agent microcapsule has a porous micro-nano shell structure, so that the curing agent can be stably and uniformly dispersed in the epoxy resin single-component adhesive. Specifically, the porous micro-nano shell structure refers to that nano-scale holes and micron-scale holes are distributed on the outer surface of a microcapsule wall material.
Compared with the traditional latent curing agent, the curing agent microcapsule provided by the invention really realizes the 'latent' of the curing agent in the adhesive, realizes physical isolation due to microcapsule coating, does not need to additionally add an inhibitor and a polymerization inhibitor, and can stably exist in the adhesive. When the curing agent microcapsule is used, the curing agent microcapsule is cracked and deblocked through temperature rise or external force, so that the rapid curing of the adhesive can be realized.
Microcapsules (microcapsules) generally refer to microspheres having a core/shell structure and a particle size of 1 to 1000 μm. The relatively inert shell material is adopted to wrap the relatively active or to-be-protected core material, so that microencapsulation is realized, and the practical engineering application is facilitated.
Curing agents, also known as hardeners, curing agents or setting agents, are a class of substances or mixtures that enhance or control the curing reaction.
Drawings
FIG. 1 is one of the scanning electron micrographs of the curing agent microcapsules prepared in example 1.
FIG. 2 is the second SEM photograph of curing agent microcapsules prepared in example 1.
Fig. 3 is one of the scanning electron micrographs of the curing agent microcapsules prepared in example 2.
FIG. 4 is a second SEM photograph of the curing agent microcapsules prepared in example 2.
Fig. 5 is one of the scanning electron micrographs of the curing agent microcapsules prepared in example 3.
FIG. 6 is a second SEM photograph of the curing agent microcapsules prepared in example 3.
Detailed Description
The following are specific examples of the present invention, and the technical solutions of the present invention are further described with reference to the examples, but the present invention is not limited to the examples.
In some embodiments of the present invention, the present invention provides a curing agent microcapsule, including a capsule core and a wall material wrapping the capsule core, where a preparation raw material of the capsule core includes at least one of aromatic polyamine, polyamine salt, alicyclic amine and aliphatic amine, a preparation raw material of the wall material includes at least one of polyvinyl microspheres, polystyrene microspheres and polyacrylate microspheres, and the wall material has a micro-nano porous structure.
It can be understood that compared with the common traditional latent curing agent, the curing agent microcapsule of the invention can realize the real physical isolation effect by using the encapsulation technology, and can block the interaction of the curing agent and the matrix epoxy resin, thereby having longer storage life.
It can be understood that the curing agent microcapsule of the invention takes at least one of polyvinyl microspheres, polystyrene microspheres and polyacrylate microspheres as a wall material and at least one of aromatic polyamine, polyamine salt, alicyclic amine and aliphatic amine as a capsule core material, and has the characteristics of high coating rate, stability, difficult release and convenient storage and transportation.
The curing agent microcapsule has a porous micro-nano shell structure, so that the curing agent can be stably and uniformly dispersed in the epoxy resin single-component adhesive. Specifically, the porous micro-nano shell structure refers to that nano-scale holes and micron-scale holes are distributed on the outer surface of a microcapsule wall material.
In addition, compared with the traditional latent curing agent, the curing agent microcapsule provided by the invention really realizes the 'latent' of the curing agent in the adhesive, and because of microcapsule coating, physical isolation is realized, no inhibitor or polymerization inhibitor needs to be additionally added, and the curing agent microcapsule can also exist stably in the adhesive. When the curing agent microcapsule is used, the curing agent microcapsule is cracked and deblocked through temperature rise or external force, and the rapid curing of the adhesive can be realized.
In some embodiments of the invention, the mass ratio of the raw materials for preparing the wall material to the raw materials for preparing the capsule core is 1-5:3.
In some embodiments of the invention, the mass ratio of the raw materials for preparing the wall material to the raw materials for preparing the capsule core is 1-3:3.
In still other embodiments of the present invention, the present invention provides a method of preparing a curing agent microcapsule comprising the steps of:
s1: dispersing the water solution of the emulsifier to obtain a water phase;
s2: adding a wall material preparation raw material and a capsule core preparation raw material into a volatile solvent, and dispersing to obtain an oil phase;
s3: adding the oil phase into the water phase, performing emulsion reaction at room temperature, and raising the temperature until the volatile solvent is volatilized to obtain a suspension;
s4: and centrifuging the suspension to obtain a solid product, namely the curing agent microcapsule.
It should be noted that there are three main methods for preparing the microcapsule curing agent. One is an interfacial polymerization method, which has some insurmountable disadvantages, such as long reaction time, complicated reaction equipment, and high preparation cost of required materials. The other method is an in-situ polymerization method, which is greatly influenced by an emulsifier, reaction temperature, pH value, stirring speed and the like, and most shell materials of the method are synthetic resin, and formaldehyde is needed, so that the method is not environment-friendly. And the third method is a solvent evaporation method, compared with other methods, the microcapsule curing agent prepared by the solvent evaporation method does not need to adjust the pH value, heat and cool, and special reaction reagents, and the method has the advantages of simple equipment, low cost, easy popularization and suitability for large-scale industrial production. However, the thermal stability is poor and the core material content is low, thus affecting the storage life of the curing agent and the performance of the cured colloid.
Aiming at the defects of the prior art, the technical scheme for preparing the curing agent microcapsule provides a method for preparing the curing agent microcapsule which has the advantages of adjustable porous micro-nano structure, high core material content and good stability.
It can be understood that, in the preparation method of the invention, the aqueous solution of the emulsifier is dispersed to obtain the water phase; adding a wall material preparation raw material and a capsule core preparation raw material into a volatile solvent, and dispersing to obtain an oil phase; then adding the oil phase into the water phase, carrying out an emulsification reaction at room temperature, and raising the temperature until the volatile solvent volatilizes to obtain a suspension; and finally, centrifuging the suspension to obtain a solid product, namely the curing agent microcapsule. According to the method, the adjustment of the wall material micro-nano porous structure is realized by adjusting the ratio of the core material to the wall material (core-wall ratio). According to actual needs, curing agent microcapsules with different micro-nano porous structures can be prepared.
In some embodiments of the invention, the emulsifier is present in the aqueous solution in an amount of from 0.1wt% to 2wt%.
In some embodiments of the invention, the emulsifying agent comprises at least one of gum arabic, gelatin, and polyvinyl alcohol.
In some embodiments of the invention, in step S1, the dispersing is performed by mechanical stirring.
In some embodiments of the invention, the mechanical agitation is at a speed of from 300rpm to 450rpm.
In some embodiments of the invention, the time of mechanical stirring is from 10min to 30min.
In some embodiments of the invention, in step S2, the mass-to-volume ratio of the raw material for preparing the wall material to the volatile solvent is 1g to 5 g.
In some embodiments of the invention, in step S2, the mass-to-volume ratio of the raw material for preparing the capsule core to the volatile solvent is 1g to 5 g.
In some embodiments of the invention, in step S2, the dispersion is performed in an ultrasound device.
In some embodiments of the invention, in step S2, the volatile solvent comprises at least one of dichloromethane, trichloromethane and acetone.
In some embodiments of the invention, in step S3, the volume ratio of the oil phase to the aqueous phase is 1:2 to 10.
In some embodiments of the invention, step S3, the oil phase is added to the aqueous phase, requiring a slow addition.
In some embodiments of the present invention, in step S3, the oil phase may be added dropwise to the water phase within 5min to 10 min.
In some embodiments of the invention, in step S3, the time of the emulsification reaction at room temperature is: stirring and emulsifying for 10-30 min, and stirring and reacting for 1-2 h at room temperature (normal temperature).
In some embodiments of the invention, in step S3, after the emulsification reaction at room temperature, the temperature is raised to 35 ℃ to 45 ℃, and the stirring is performed for 3h to 5h, so as to volatilize the volatile solvent.
In some embodiments of the invention, in step S3, after the emulsification reaction at room temperature, the temperature is raised to 38 ℃ to 40 ℃, and the stirring is performed for 3h to 5h, so as to volatilize the volatile solvent.
In some embodiments of the present invention, the preparation method of the present invention further comprises washing and drying the solid product in step S4.
In still other embodiments of the present invention, the present invention provides the use of curing agent microcapsules in the preparation of epoxy adhesives.
It can be understood that the curing agent microcapsule of the present invention is used in the preparation of epoxy resin adhesives, thereby having all the technical effects of the curing agent microcapsule. Specifically, the method comprises the following steps:
compared with the common traditional latent curing agent, the curing agent microcapsule disclosed by the invention can realize a real physical isolation effect by utilizing an encapsulation technology, and the interaction between the curing agent and the matrix epoxy resin is blocked, so that the storage life of the epoxy resin adhesive is longer.
When the epoxy resin adhesive is prepared, the curing agent microcapsule takes at least one of polyvinyl microspheres, polystyrene microspheres and polyacrylate microspheres as a wall material and at least one of aromatic polyamine, polyamine salt, alicyclic amine and aliphatic amine as a capsule core material, so that the curing agent microcapsule has the characteristics of high coating rate, stability, difficult release and convenience in storage and transportation.
When the epoxy resin adhesive is prepared, the curing agent microcapsule disclosed by the invention has a porous micro-nano shell structure, so that the curing agent can be stably and uniformly dispersed in the epoxy resin single-component adhesive. Specifically, the porous micro-nano shell structure refers to that nano-scale holes and micron-scale holes are distributed on the outer surface of a microcapsule wall material.
Compared with the traditional latent curing agent, the curing agent microcapsule provided by the invention really realizes the 'latent' of the curing agent in the adhesive, realizes physical isolation due to microcapsule coating, does not need to additionally add an inhibitor and a polymerization inhibitor, and can stably exist in the adhesive. When the curing agent microcapsule is used, the curing agent microcapsule is cracked and deblocked through temperature rise or external force, so that the rapid curing of the adhesive can be realized.
The microcapsules (microcapsules) generally have a core/shell structure and are microspheres having a particle diameter of 1 to 1000 μm. The relatively inert shell material is adopted to wrap the relatively active or to-be-protected core material, so that microencapsulation is realized, and the practical engineering application is facilitated.
It should also be noted that a curing agent, also known as a hardener, curing agent or setting agent, is a substance or mixture that enhances or controls the curing reaction.
The technical scheme of the invention is better understood by combining the specific embodiments.
Example 1
The embodiment prepares a curing agent microcapsule, and the specific preparation process is as follows:
(1) Lg of the polyacrylate microsphere was weighed and dissolved in 30mL of methylene chloride, and 3g of 4,4' -diaminodicyclohexylmethane (H) was added thereto 12 MDA), i.e. shell/core =1:3;
(2) Dispersing the oil phase uniformly by using an ultrasonic oscillator to obtain an oil phase;
(3) Adding the obtained oil phase into 120mL of aqueous solution containing 1.5wt% of polyvinyl alcohol at normal temperature and at the rotating speed of 800rpm, firstly stirring the mixture for 1h at normal temperature, then stirring the mixture for 5h at 40 ℃ to slowly volatilize dichloromethane, thus obtaining polyacrylate microsphere coated amine curing agent microcapsule suspension;
(4) And sieving, washing with water, filtering, and drying to obtain white microcapsule product.
See fig. 1 and 2. Fig. 1 and 2 are scanning electron micrographs of the curing agent microcapsules prepared in this example. The average particle size of the prepared microcapsule is about 220 μm, the capsule core content is 23%, and the capsule core content is obtained by TGA (thermo gravimetric analysis) test and analysis calculation.
Example 2
The embodiment prepares a curing agent microcapsule, and the specific preparation process is as follows:
(1) Weighing 2gPolyacrylate microspheres were dissolved in 30mL of methylene chloride, and 3g of H was added thereto 12 MDA, i.e. shell/core =2:3;
(2) Uniformly dispersing the oil phase by using an ultrasonic oscillator to obtain an oil phase;
(3) Adding the obtained oil phase into 120mL of aqueous solution containing 1wt% of polyvinyl alcohol at normal temperature and at the rotating speed of 800rpm, stirring the mixture for 1h at normal temperature in an open way, then stirring the mixture for 5h at 40 ℃ in an open way, and slowly volatilizing dichloromethane to obtain polyacrylate microsphere coated amine curing agent microcapsule suspension;
(4) And sieving, washing with water, filtering, and drying to obtain white microcapsule product.
Referring to fig. 3 and 4, fig. 3 and 4 are scanning electron micrographs of the curing agent microcapsules prepared in this example. The prepared microcapsules have the volume average particle size of about 220 mu m through analysis, the capsule core content is 25 percent, and the capsule core content is obtained through TGA (thermal gravimetric analysis) test and analysis calculation.
Example 3
The embodiment prepares a curing agent microcapsule, and the specific preparation process is as follows:
(1) 3g of polyacrylate microspheres were weighed and dissolved in 30mL of methylene chloride, and 3g of H was added thereto 12 MDA, i.e. shell/core =3:3;
(2) Uniformly dispersing the oil phase by using an ultrasonic oscillator to obtain an oil phase;
(3) Adding the obtained oil phase into 120mL of aqueous solution containing 1.5wt% of polyvinyl alcohol at normal temperature and at the rotation speed of 800rpm, firstly stirring the mixture for 1h at normal temperature in an open manner, then stirring the mixture for 5h at 40 ℃ in an open manner, and slowly volatilizing dichloromethane to obtain polyacrylate microsphere coated amine curing agent microcapsule suspension;
(4) And sieving, washing with water, filtering, and drying to obtain white microcapsule product.
Refer to fig. 5 and 6. Fig. 5 and 6 are scanning electron micrographs of the curing agent microcapsules prepared in this example. The microcapsules prepared were analyzed to have a volume average particle size of about 180 μm and a core content of 28% as calculated by TGA (thermogravimetric analysis) test.
The polyacrylate microspheres used as the starting materials in examples 1 to 3 were obtained from a Michael reagent net.
Example 4
The embodiment prepares a curing agent microcapsule, and the specific preparation process is as follows:
(1) Weighing 1g of polystyrene microspheres, dissolving in 10ml of dichloromethane, and adding 3g of isophorone diamine, namely core/wall =3:1;
(2) Dispersing the oil phase uniformly by using an ultrasonic oscillator to obtain an oil phase;
(3) Adding the obtained oil phase into 120ml of aqueous solution containing 1.5wt% of polyvinyl alcohol at normal temperature and at the rotating speed of 800rpm, firstly stirring the mixture for 1 hour in an open way at normal temperature, then stirring the mixture for 5 hours in an open way at 40 ℃, and slowly volatilizing dichloromethane to obtain polystyrene microsphere coated amine curing agent microcapsule suspension;
(4) And sieving, washing with water, filtering, and drying to obtain white microcapsule product. The microcapsules prepared were analyzed to have a volume average particle size of about 190 μm and a core content of 14%.
Example 5
The embodiment prepares a curing agent microcapsule, and the specific preparation process is as follows:
(1) Weighing 2g of polyvinyl microspheres, dissolving the polyvinyl microspheres in 20ml of dichloromethane, and adding 5g of isophorone diamine into the polyvinyl microspheres, wherein the core/wall =5:2;
(2) Dispersing the oil phase uniformly by using an ultrasonic oscillator to obtain an oil phase;
(3) Adding the obtained oil phase into 120ml of aqueous solution containing 1.5wt% of polyvinyl alcohol at normal temperature and at the rotating speed of 800rpm, firstly stirring the mixture for 1 hour in an open way at normal temperature, then stirring the mixture for 5 hours in an open way at 40 ℃, and slowly volatilizing dichloromethane to obtain polystyrene microsphere coated amine curing agent microcapsule suspension;
(4) And sieving, washing with water, filtering, and drying to obtain white microcapsule product. The microcapsules prepared were analyzed to have a volume average particle size of about 200 μm and a core content of 18%.
Example 6
This example provides the use of the curing agent microcapsules of the present invention in thread-locking adhesives.
The curing agent microcapsule prepared in example 1 was blended with an epoxy resin (E51) to obtain a thread-locking compound.
The stable pot life of the threadlocking glue at room temperature was observed. The thread locking glue is not cured for more than 10 days, which shows that the thread locking glue obtained by blending the curing agent microcapsule and the epoxy resin can be stably stored for more than 10 days.
The screw locking glue is pre-coated on the bolts (M2-M10), and the test result is as follows: the breaking torque of the screw-out is between 10 N.m and 25 N.m, and the breaking torque meets the standard requirement. That is, the microcapsule curing agent of the present invention enables the strength of the cured epoxy resin to meet the curing standard of the conventional epoxy system.
The present invention has been described in detail with reference to the embodiments, but the present invention is not limited to the embodiments described above, and various changes can be made within the knowledge of those skilled in the art without departing from the gist of the present invention.
Claims (10)
1. The curing agent microcapsule is characterized by comprising a capsule core and a wall material wrapping the capsule core, wherein a preparation raw material of the capsule core comprises at least one of aromatic polyamine, polyamine salt, alicyclic amine and aliphatic amine, a preparation raw material of the wall material comprises at least one of polyvinyl microspheres, polystyrene microspheres and polyacrylate microspheres, and the wall material has a micro-nano porous structure.
2. The curing agent microcapsule according to claim 1, wherein the mass ratio of the raw materials for preparing the wall material to the raw materials for preparing the capsule core is 1 to 5:3.
3. A process for preparing the curing agent microcapsules of claim 1 or 2 comprising the steps of:
s1: dispersing the aqueous solution of the emulsifier to obtain a water phase;
s2: adding a preparation raw material of a wall material and a preparation raw material of a capsule core into a volatile solvent, and dispersing to obtain an oil phase;
s3: adding the oil phase into the water phase, carrying out an emulsification reaction at room temperature, and then raising the temperature until the volatile solvent volatilizes to obtain a suspension;
s4: and centrifuging the suspension to obtain a solid product, namely the curing agent microcapsule.
4. The method according to claim 3, wherein the emulsifier is present in the aqueous solution in an amount of 0.1 to 2 wt.%.
5. The method of claim 3, wherein the emulsifying agent comprises at least one of gum arabic, gelatin, and polyvinyl alcohol.
6. The method of claim 3, wherein in the step S2, the mass-to-volume ratio of the raw material for preparing the wall material to the volatile solvent is 1 g-5g.
7. The method according to claim 3, wherein in the step S2, the mass volume ratio of the raw materials for preparing the capsule core to the volatile solvent is 1 g-5g.
8. The method of claim 3, wherein in step S2, the volatile solvent comprises at least one of dichloromethane, chloroform, and acetone.
9. The method according to claim 3, wherein in step S3, the volume ratio of the oil phase to the water phase is 1:2-10.
In step S3, the oil phase is added to the aqueous phase, which needs to be slowly added.
10. Use of a curing agent microcapsule according to claim 1 or 2 or a curing agent microcapsule obtainable by a process according to any one of claims 3 to 9 in the preparation of an epoxy adhesive.
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| JPH11193344A (en) * | 1998-10-14 | 1999-07-21 | Nitto Denko Corp | Cured epoxy resin product and curing method for obtaining same |
| CN101016369A (en) * | 2007-03-02 | 2007-08-15 | 浙江大学 | Microcapsule incubated epoxide curing agent and preparing method thereof |
| CN102423673A (en) * | 2011-07-28 | 2012-04-25 | 西北工业大学 | Latent microcapsule curing agent initiating thermosetting epoxy resin curing at medium temperature and preparation method of adhesive thereof |
| CN104193965A (en) * | 2014-08-21 | 2014-12-10 | 江汉大学 | Imidazole epoxy curing agent micro capsule and preparation method thereof |
| CN111303383A (en) * | 2020-02-19 | 2020-06-19 | 东华大学 | Latent polyamine epoxy resin curing agent microcapsule and preparation and application thereof |
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2022
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH11193344A (en) * | 1998-10-14 | 1999-07-21 | Nitto Denko Corp | Cured epoxy resin product and curing method for obtaining same |
| CN101016369A (en) * | 2007-03-02 | 2007-08-15 | 浙江大学 | Microcapsule incubated epoxide curing agent and preparing method thereof |
| CN102423673A (en) * | 2011-07-28 | 2012-04-25 | 西北工业大学 | Latent microcapsule curing agent initiating thermosetting epoxy resin curing at medium temperature and preparation method of adhesive thereof |
| CN104193965A (en) * | 2014-08-21 | 2014-12-10 | 江汉大学 | Imidazole epoxy curing agent micro capsule and preparation method thereof |
| CN111303383A (en) * | 2020-02-19 | 2020-06-19 | 东华大学 | Latent polyamine epoxy resin curing agent microcapsule and preparation and application thereof |
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