CN111349415A - Single-component epoxy resin composition and preparation method thereof - Google Patents
Single-component epoxy resin composition and preparation method thereof Download PDFInfo
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- CN111349415A CN111349415A CN201811591735.0A CN201811591735A CN111349415A CN 111349415 A CN111349415 A CN 111349415A CN 201811591735 A CN201811591735 A CN 201811591735A CN 111349415 A CN111349415 A CN 111349415A
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- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
- C09J163/00—Adhesives based on epoxy resins; Adhesives based on derivatives of epoxy resins
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L63/00—Compositions of epoxy resins; Compositions of derivatives of epoxy resins
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- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
- C09J11/00—Features of adhesives not provided for in group C09J9/00, e.g. additives
- C09J11/02—Non-macromolecular additives
- C09J11/06—Non-macromolecular additives organic
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Abstract
The invention provides a low-viscosity single-component epoxy resin composition, which comprises at least one epoxy resin, at least one liquid anhydride curing agent, at least one curing accelerator and at least one thixotropic auxiliary agent. The low-viscosity single-component epoxy resin composition is suitable for being used as an encapsulating adhesive, is convenient to use, and can be directly used without weighing, proportioning and stirring; the resin has low viscosity and is suitable for various construction processes; the leveling and defoaming effects in the gluing and baking processes are good, and the film forming thickness is moderate; the cured material has high bonding strength, low shrinkage rate and good electrical property, is not easy to crack, is particularly suitable for being used as encapsulating glue, and is particularly suitable for encapsulating the neck of rotors of electric tools and the like with high rotating speed, large vibration and high working temperature.
Description
Technical Field
The invention relates to a single-component epoxy resin composition, a preparation method thereof and application of the single-component epoxy resin composition as an encapsulating adhesive.
Background
The working environment of the rotor of the electric tool or other high-speed motor with high power, high rotating speed and high impact vibration is severe, and the rotor of the electric tool or other high-speed motor is often required to operate in the environment with high temperature, high rotating speed and high impact vibration. At high rotating speed, carbon brush particles or other impurities are easy to damage paint films on the surfaces of enameled wires at the commutator part. In order to avoid damage to the rotor, a layer of encapsulating glue with a certain thickness (about 0.1-2 mm) is coated on the basis of the insulating paint, and the encapsulating glue has the functions of protection, filling, repair and the like besides the basic insulating performance. The encapsulating layer has the main function of adding a protective layer to the enameled wire at the commutator part, so that the service life of the motor can be obviously prolonged.
At present, most of the main encapsulating glue in the domestic market is a two-component product no matter epoxy resin, unsaturated polyester or modified epoxy, namely, the resin and the curing agent are supplied to users in a two-component form. The dual-component product needs to be weighed and mixed in proportion before use, and in the actual use process, the conditions of inaccurate weighing and proportioning, uneven stirring and excessive bubble brought by stirring are often caused, so that the quality problems of no dryness, low strength, more bubbles and the like of the resin are caused. The single-component epoxy encapsulating adhesive used in the market at present is resin added with a curing agent. Although the single-component epoxy encapsulating glue avoids the problems of weighing and stirring in use, the single-component epoxy encapsulating glue cannot be dripped by a peristaltic pump due to too large viscosity at normal temperature, so that automatic paint dripping is inconvenient, and the production efficiency is influenced.
The invention provides the single-component epoxy resin composition through reasonable formula design, which has the advantages of good storage stability, low viscosity, moderate film thickness after curing, high strength, strong high-temperature bonding force, small shrinkage, difficult cracking, smooth surface and the like, can be dripped by a peristaltic pump, and is suitable for being used as an encapsulating adhesive.
Disclosure of Invention
The invention aims to provide a single-component epoxy resin composition which is suitable for being used as an encapsulating adhesive, has good storage stability, low viscosity, moderate film thickness after curing, high strength, strong high-temperature bonding force, small shrinkage, difficult cracking and smooth surface and a preparation method thereof, and can be dripped by a peristaltic pump.
The technical scheme for achieving the aim of the invention can be summarized as follows:
1. a one-part epoxy resin composition comprising at least one epoxy resin, at least one liquid anhydride curing agent, at least one curing accelerator, and at least one thixotropic adjuvant.
2. The one-component epoxy resin composition according to item 1, wherein the epoxy resin is selected from one or more of bisphenol A type epoxy resins, bisphenol F type epoxy resins, phenol aldehyde type epoxy resins, and glycidyl amine type epoxy resins which are liquid at room temperature.
3. The one-component epoxy resin composition according to item 1 or 2, wherein the viscosity of the epoxy resin at 25 ℃ is 2000-15000cps, preferably 3000-12000cps, and/or the viscosity at 50 or 66 ℃ is 3000-7000cps, preferably 4000-6000cps, and/or the epoxy equivalent of the epoxy resin is 80-250 g/equivalent, preferably 100-200 g/equivalent.
4. The one-component epoxy resin composition according to any one of items 1 to 3, wherein the epoxy resin is used in an amount of 15 to 60 parts by weight, preferably 20 to 40 parts by weight, based on 100 parts by weight of the one-component epoxy resin composition.
5. The one-component epoxy resin composition according to any one of items 1 to 4, wherein the liquid acid anhydride curing agent is selected from one or more of methyl hexahydrophthalic anhydride, methyl tetrahydrophthalic anhydride and methyl nadic anhydride.
6. The one-component epoxy resin composition according to any one of items 1 to 5, wherein the liquid acid anhydride curing agent is used in an amount of 15 to 60 parts by weight, preferably 20 to 40 parts by weight, based on 100 parts by weight of the one-component epoxy resin composition.
7. The one-component epoxy resin composition according to any one of items 1 to 6, wherein the curing accelerator is a latent curing accelerator, preferably the curing accelerator is selected from one or more of an imidazole-type accelerator having a melting point higher than 150 ℃, a microcapsule-coated imidazole-type accelerator, an organozinc-type accelerator, a boramine-type accelerator, and a titanate.
8. The one-component epoxy resin composition according to any one of items 1 to 7, wherein the thixotropy auxiliary is selected from one or more of fumed silica, organobentonite and organothixotropic agent, preferably fumed silica and organobentonite, more preferably hydrophobically modified fumed silica.
9. The process according to item 8, wherein the hydrophobically modified fumed silica is selected from silane-modified hydrophobic fumed silicas and polysiloxane-modified hydrophobic fumed silicas, preferably polysiloxane-modified hydrophobic fumed silicas.
10. The one-component epoxy resin composition according to item 8, wherein the fumed silica has an average particle diameter of 8 to 100nm, preferably 10 to 50nm, most preferably 10 to 20 nm.
11. The one-component epoxy resin composition according to item 8, wherein the organobentonite thixotropic agent is an oily organobentonite thixotropic agent of 200-3000 mesh, more preferably an organobentonite thixotropic agent which does not require pre-gel activation, and/or the organothixotropic agent is a polyurea compound.
12. The one-component epoxy resin composition according to any one of items 1 to 11, wherein the thixotropy auxiliary is used in an amount of 1 to 8 parts by weight, preferably 2 to 5 parts by weight, based on 100 parts by weight of the one-component epoxy resin composition.
13. The one-component epoxy resin composition according to any one of items 1 to 12, further comprising an epoxy diluent, preferably the epoxy diluent is selected from one or more of glycidyl ethers of dihydric and trihydric alcohols which are liquid at room temperature.
14. The one-component epoxy resin composition according to any one of items 1 to 13, which further comprises a filler and a defoaming agent.
15. The one-component epoxy resin composition according to any one of items 1 to 14, wherein the viscosity of the one-component epoxy resin composition is from 30 to 120Pas, preferably from 40 to 100Pas, and/or the shore D hardness of the one-component epoxy resin composition after curing is from 85 to 95, and/or the glass transition temperature of the one-component epoxy resin composition after curing is from 120-.
16. The one-component epoxy resin composition according to any one of items 1 to 15, which comprises the following components in parts by weight based on 100 parts by weight of the one-component epoxy resin composition:
20 to 40 parts by weight of an epoxy resin,
20-40 parts by weight of an acid anhydride curing agent,
0.8 to 5 parts by weight of a curing accelerator,
2-5 parts by weight of a thixotropic auxiliary agent,
1 to 5 parts by weight of an epoxy diluent,
20 to 50 parts by weight of a filler, and
0.01-0.5 weight portion of defoaming agent.
17. A method for preparing the one-component epoxy resin composition of any one of items 1 to 16, comprising the steps of:
1) mixing and uniformly dispersing the components of the single-component epoxy resin composition except the curing accelerator; and
2) the curing accelerator is added and uniformly dispersed at a temperature of the mixture of not more than 30 ℃, preferably not more than 25 ℃ to obtain the one-component epoxy resin composition.
18. A method of curing a one-component epoxy resin composition as defined in any one of items 1 to 16, which comprises applying the one-component epoxy resin composition to a surface of a workpiece and then baking at 130-150 ℃ for 30-60 minutes.
19. Use of the one-component epoxy resin composition as defined in any one of claims 1 to 16 as an encapsulant, in particular as an encapsulant for rotors, especially in the encapsulation of the neck of rotors of electric tools.
Drawings
FIG. 1 is a photograph of an encapsulated rotor from example 6 using the epoxy resin composition of example 3 as the encapsulating glue.
Fig. 2 is a photograph of a cross-section of the encapsulated rotor of fig. 1.
FIG. 3 is a photograph of an encapsulated rotor from example 6 using the epoxy resin composition of example 1 as an encapsulating glue.
FIG. 4 is a photograph of an encapsulated rotor from example 6 using the epoxy resin composition of comparative example 1 as an encapsulating glue.
Detailed Description
One aspect of the present invention relates to a one-component epoxy resin composition comprising at least one epoxy resin, at least one liquid anhydride curing agent, at least one curing accelerator, and at least one thixotropic adjuvant.
The epoxy resin is preferably liquid at room temperature. In a preferred embodiment of the present invention, the epoxy resin is selected from one or more of bisphenol a type epoxy resin, bisphenol F type epoxy resin, novolac type epoxy resin, and glycidyl amine epoxy resin which are liquid at room temperature.
According to the invention, the viscosity of the epoxy resin may be 2000-15000cps, such as 2000-15000, 4000-14000, 6000-12000 or 8000-10000cps, preferably 3000-12000 cps. The viscosity is the viscosity measured at 25 ℃.
The viscosity of the epoxy resin can also be measured at 50 ℃ or 66 ℃ when it is solid or too viscous at 25 ℃. In one embodiment of the invention, the viscosity of the epoxy resin is 3000-7000cps, such as 5000cps, preferably 4000-6000 cps. The viscosity is the viscosity measured at 50 ℃ or 66 ℃.
The epoxy equivalent of the epoxy resin may be 80-250 g/equivalent, for example 80-230, 110-200, 140-170 g/equivalent, preferably 100-200 g/equivalent.
Preferably, the bisphenol A type epoxy resin has an epoxy equivalent of 180-190 g/equivalent; viscosity at 25 ℃ is 10000-12000 cps. More preferably, bisphenol A type epoxy resin is bisphenol A type epoxy resin CYD-128. Preferably, the bisphenol F type epoxy resin has an epoxy equivalent of 160-180 g/equivalent; viscosity at 25 ℃ is 3000-5000 cps. More preferably, bisphenol F type epoxy resin NPEF-170 is selected as the bisphenol F type epoxy resin. Preferably, the epoxy equivalent of the novolac type epoxy resin is 170-190 g/eq. More preferably, the phenolic epoxy resin is phenolic epoxy resin NPPN-638. Preferably, the glycidyl amine epoxy resin has an epoxy equivalent weight of 110-125 g/eq; the viscosity at 50 ℃ is 3000-6000 cps. More preferably, the glycidyl amine epoxy resin is selected from tetra-functional glycidyl amine epoxy resin MY 721.
The epoxy resin may be used in an amount of 15 to 60 parts by weight, for example 20 to 60, 25 to 50, 30 to 40 or 35 to 60 parts by weight, preferably 20 to 40 parts by weight, based on 100 parts by weight of the one-component epoxy resin composition.
The one-part epoxy resin composition of the present invention comprises at least one liquid anhydride curing agent. According to a preferred embodiment of the present invention, the liquid anhydride curing agent is selected from one or more of methyl hexahydrophthalic anhydride, methyl tetrahydrophthalic anhydride and methyl nadic anhydride.
The liquid anhydride curing agent may be used in an amount of 15 to 60 parts by weight, for example, 20 to 55, 25 to 50, 30 to 45, 35 to 40 parts by weight, preferably 20 to 40 parts by weight, based on 100 parts by weight of the one-part epoxy resin composition.
The one-component epoxy composition of the present invention comprises at least one cure accelerator. According to a preferred embodiment of the present invention, the curing accelerator is a latent curing accelerator. The latent cure accelerator is inactive or very low active at room temperature. The latent cure accelerator will only drive the reaction when the temperature is raised. In a preferred embodiment, the curing accelerator is selected from one or more of imidazole-type accelerators (such as 2MA-OK of four kingdoms) having a melting point above 150 ℃, microcapsule-coated imidazole-type accelerators, organozinc-type accelerators (such as zinc naphthenate), boramine-type accelerators (such as boron trifluoride monoethylamine complex) and titanates (such as n-butyl titanate). More preferably, the curing accelerator is selected from the group consisting of imidazole compound fine powder 2MA-OK having a melting point higher than 150 ℃, microcapsule-coated imidazole accelerator, boron amine complex, and curing accelerator ICAM-8413 metal complex.
The curing accelerator may be used in an amount of 0.5 to 8 parts by weight, for example, 0.5 to 8, 0.8 to 7, 1 to 6, 2 to 5, 3 to 4 parts by weight, preferably 0.8 to 5 parts by weight, based on 100 parts by weight of the one-part epoxy resin composition.
The one-component epoxy resin composition of the present invention comprises at least one thixotropic auxiliary. In a preferred embodiment the thixotropic adjuvant is selected from one or more of fumed silica, organobentonite and organothixotropic agents.
In a preferred embodiment, the thixotropic adjuvant is selected from fumed silica and organobentonite, more preferably fumed silica.
The fumed silica can be a hydrophilic fumed silica and a hydrophobic fumed silica. Hydrophobic fumed silicas are more preferred according to the invention. The hydrophobic fumed silica can be a silane-modified hydrophobic fumed silica, preferably a chlorosilane, such as dimethyldichlorosilane-modified hydrophobic fumed silica, and also a polysiloxane-modified hydrophobic fumed silica, such as a dimethylsilicone liquid-modified fumed silica.
Preferably the fumed silica has an average particle size of from 8 to 100nm, preferably from 10 to 50nm, such as from 20 to 40nm or from 30 to 50nm, most preferably from 10 to 20nm, such as from 12 to 20nm, 12 to 18nm, 12 to 16nm or 12 to 14 nm.
The preferred organobentonite is 200-3000 mesh oily organobentonite, more preferably selected from organobentonite thixotropic agents which can be added directly without pre-gel activation, such as GARAMITE-7305. If the organic thixotropic agent needing pre-gelling activation is selected, an activating agent and a solvent are added according to the specification of the corresponding organic bentonite for pre-gelling, and then the organic thixotropic agent is added into the formula.
In one embodiment, the organic thixotropic agent is selected from polyurea compounds, the relative molecular mass of which may be 2000-20000.
More preferably, the thixotropic auxiliary agent is selected from Aerosil 200 fumed silica, GARAMITE-7305 organobentonite, AEROSILR 974 hydrophobic fumed silica, CAB-O-
TS-720 hydrophobic fumed silica. More preferably, the organic thixotropic agent is selected from the polyurea compound BYK 415.
The thixotropic auxiliary may be used in an amount of 1 to 8 parts by weight, for example 2 to 8, 3 to 7, 4 to 8, 5 to 7, 2 to 6 parts by weight, preferably 2 to 5 parts by weight, based on 100 parts by weight of the one-component epoxy resin composition.
In one embodiment of the present invention, the one-component epoxy resin composition of the present invention may further comprise at least one epoxy diluent. The epoxy diluent contains 1, 2 or 3 or more epoxy groups, preferably 2 or 3 epoxy groups, in the molecule. The epoxy diluent is a liquid at room temperature.
Preferably, the epoxy diluent is selected from one or more of glycidyl ethers of dihydric and trihydric alcohols which are liquid at room temperature. The viscosity of the epoxy diluent may be from 5 to 20 cps. In a preferred embodiment, the epoxy diluent is selected from at least one of diglycidyl ethers of diols having 2 to 6 carbon atoms (e.g., 2, 3, 4, 5, or 6 carbon atoms), such as hexanediol diglycidyl ether, butanediol diglycidyl ether, neopentyl glycol diglycidyl ether, and glycerol triglycidyl ether.
The epoxy diluent may be used in an amount of 0.5 to 10 parts by weight, for example, 1 to 10, 2 to 8, 3 to 7, 4 to 6 parts by weight, preferably 1 to 5 parts by weight, based on 100 parts by weight of the one-component epoxy resin composition.
The one-component epoxy resin composition of the present invention may further comprise a filler. The diameter of the filler may be 1 to 100 microns, preferably 5 to 50 microns. Preferably, the filler is one or more selected from silica micropowder, alumina, aluminum hydroxide, glass powder, glass beads and chopped glass fibers.
The filler may be used in an amount of 10 to 60 parts by weight, preferably 20 to 50 parts by weight, based on 100 parts by weight of the one-component epoxy resin composition.
The one-component epoxy resin composition of the present invention may further comprise an antifoaming agent. The defoaming agent may be a silicone-based defoaming agent. Preferably, the defoaming agent is at least one selected from BYK A535 defoaming agent and BYK067 defoaming agent.
The amount of the antifoaming agent can be selected by those skilled in the art according to the actual needs. The defoaming agent may be used, for example, in an amount of 0.01 to 0.5 parts by weight, such as 0.05 to 4, 0.1 to 0.3, 0.2 to 0.3 parts by weight, based on 100 parts by weight of the one-component epoxy resin composition.
In a preferred embodiment, the one-component epoxy resin composition of the present invention may have a viscosity of 30 to 120Pas, for example 40 to 110, 50 to 100, 60 to 90, 70 to 80Pas, preferably 40 to 100Pas, at 25 ℃.
According to the present invention, viscosity can be measured using a Brookfield viscometer.
The shore hardness D of the cured single-component epoxy resin composition can be 85-95.
The glass transition temperature of the cured single-component epoxy resin composition can be 120-170 ℃. The glass transition temperature can be measured by DSC.
According to a preferred embodiment of the present invention, the one-component epoxy resin composition of the present invention comprises the following components in parts by weight, based on 100 parts by weight of the one-component epoxy resin composition:
20 to 40 parts by weight of an epoxy resin,
20-40 parts by weight of an acid anhydride curing agent,
0.8 to 5 parts by weight of a curing accelerator,
2-5 parts by weight of a thixotropic auxiliary agent,
1 to 5 parts by weight of an epoxy diluent,
20 to 50 parts by weight of a filler, and
0.01-0.5 weight portion of defoaming agent.
One aspect of the present invention relates to a method of preparing a one-part epoxy resin composition of the present invention, comprising the steps of:
1) mixing and uniformly dispersing the components of the single-component epoxy resin composition except the curing accelerator;
2) the one-component epoxy resin composition is obtained by adding the curing accelerator at a temperature of the mixture of not more than 30 ℃, preferably not more than 25 ℃ and dispersing uniformly.
Preferably, the dispersion of step 1) is carried out under high-speed stirring, for example, the stirring rate in step 1) may be 650-1500rpm, preferably 800-1200 rpm; the stirring time can be 1.5-5 h. Preferably, the temperature in step 1) does not exceed 50 deg.C, more preferably does not exceed 40 deg.C.
Preferably, the dispersion of step 2) is carried out at a lower stirring rate than step 1), for example the stirring rate in step 2) may be 300-; the stirring time can be 1-3 h. Preferably, the temperature during the dispersion of step 2) is not more than 30 ℃ and more preferably not more than 25 ℃.
Of course, the resulting mixture may be further vacuum defoamed, and the pressure may be in the range of 50 to 100 pa. The defoaming can be carried out under stirring, and the stirring speed can be 20-40 rpm; the stirring time can be 1.5-3 h. The resulting mixture may then be filtered. The filtration can be carried out using a 50-100 mesh screen. The resulting composition can be finally barreled.
In one embodiment, the one-part epoxy resin composition may be prepared as follows:
dispersing the epoxy resin, the epoxy diluent, the filler, the anhydride curing agent, the thixotropic auxiliary agent and the defoaming agent at a high speed (800-;
then adding a curing accelerator at the temperature of the mixture not exceeding 25 ℃, and stirring and dispersing at a low speed (300-600rpm) at the temperature not exceeding 30 ℃ until the mixture is uniform;
then stirring and defoaming for 1.5-3 hours under the vacuum condition of 50-100 pa;
the resulting mixture was then filtered.
The temperature control can be carried out in a manner known to the person skilled in the art, for example by using cooling water.
Yet another aspect of the present invention relates to a method of curing a one-part epoxy resin composition comprising applying the one-part epoxy resin composition to a surface of a workpiece and then baking at 130-150 ℃ for 30-60 minutes.
The one-component epoxy resin composition of the present invention has the following beneficial effects: the low-viscosity single-component epoxy resin composition is convenient to use when being used as an encapsulating adhesive, and can be directly used without weighing, proportioning and stirring; the storage stability is good; the viscosity is low, and the paint is suitable for various construction processes; the leveling and defoaming effects in the gluing and baking processes are good, and the film forming thickness is moderate; the cured material has high bonding strength, low shrinkage rate, low cracking tendency and smooth surface, thus reducing the resistance in high-speed rotation, having excellent electrical performance and being particularly suitable for the neck encapsulation of rotors of electric tools and the like with high rotation speed, large vibration and high working temperature.
Finally, the invention also relates to the use of the one-component epoxy resin composition of the invention as an encapsulating compound, in particular in the encapsulation of the neck of a rotor of a power tool. The component epoxy resin composition of the present invention is particularly suitable for neck encapsulation of rotors of power tools with high rotational speeds, high vibration and high operating temperatures.
Examples
The invention will now be further illustrated, but is not limited, by the following specific examples.
Unless otherwise specified, "parts" in the examples means "parts by weight".
Example 1
30 parts of bisphenol A type epoxy resin (CYD-128) with 185 g/equivalent epoxy equivalent and 11000cps viscosity at 25 ℃, 2 parts of hexanediol diglycidyl ether serving as an epoxy diluent, 40 parts of 3000-mesh silica fine powder serving as a filler, 20 parts of liquid methyltetrahydrophthalic anhydride, 3 parts of unmodified hydrophilic fumed silica Aerosil 200 with the average particle size of 12nm and 0.01 part of an organic silicon defoamer are added into a mixing kettle, the mixture is dispersed at high speed of 1000rpm for 3 hours, the temperature of the mixture is controlled to be lower than 40 ℃ by cooling water, the high-speed dispersion is stopped, the stirring is kept at 20rpm, 1 part of 2, 4-diamine-6- (2 '-methylimidazolyl- (1')) -ethyltriazine-isocyanuric acid adduct fine powder (the melting point is higher than 260 ℃) serving as a latent curing accelerator is added into the mixture when the temperature of the mixture is lower than 25 ℃ and the stirring is carried out at 20rpm, dispersing for 2 hours at 500rpm, introducing cold water for cooling, ensuring the temperature of the mixture to be lower than 30 ℃, finally stirring and defoaming for 2 hours in vacuum at 50-100Pa, removing the vacuum, filtering with a 80-mesh steel wire mesh to obtain the low-viscosity single-component epoxy resin composition, and barreling. The performance parameters of the epoxy resin composition obtained are shown in Table 1.
Example 2
30 parts of bisphenol F type epoxy resin (NPEF-170) with the epoxy equivalent of 170 g/equivalent and the viscosity of 3500cps at 25 ℃, 1 part of hexanediol diglycidyl ether serving as an epoxy diluent, 40 parts of aluminum hydroxide with the particle size of 30 microns of inorganic filler, 22 parts of liquid methyltetrahydrophthalic anhydride, 2 parts of GARAMINE-7305 organic bentonite without pre-activation of a thixotropy auxiliary agent and 0.01 part of an organic silicon defoamer are added into a mixing kettle, the mixture is dispersed at high speed for 3 hours at 1000rpm, the temperature of the mixture is controlled to be lower than 40 ℃ by cooling water, the high-speed dispersion is stopped, the mixture is kept stirred at 20rpm, 1 part of latent curing accelerator microcapsule is added to seal imidazole when the temperature of the mixture is lower than 25 ℃, then the mixture is dispersed for 2 hours at 500rpm, the temperature is reduced by cold water, the temperature of the mixture is ensured to be lower than 30 ℃, and finally the mixture is stirred under vacuum for 2 hours under 50-100Pa for deaeration, and (4) after the vacuum is relieved, filtering the mixture by using a 80-mesh steel wire mesh to obtain the low-viscosity single-component epoxy resin composition, and barreling the low-viscosity single-component epoxy resin composition. The performance parameters of the epoxy resin composition obtained are shown in Table 1.
Example 3
20 parts of phenol-formaldehyde novolac polyglycidyl ether (with the viscosity of 5000cps @66 ℃) with the epoxy equivalent of 180 g/equivalent, 20 parts of bisphenol F epoxy resin NPEF-17010 parts with the epoxy equivalent of 170 g/equivalent and the viscosity of 3500cps at 25 ℃, 2 parts of epoxy diluent butanediol diglycidyl ether, 40 parts of glass powder with the filler particle size of 30 microns, 20 parts of liquid methyl nadic anhydride, 2 parts of hydrophobic gas-phase method silicon dioxide with the average particle size of 12nm modified by thixotropic auxiliary dimethyldichlorosilane and 0.01 part of organic silicon defoamer are added into a mixing kettle, dispersed at a high speed of 1000rpm for 3 hours, the temperature of the mixture is controlled to be lower than 40 ℃ by cooling water, the high-speed dispersion is stopped, the stirring is carried out at 20rpm, 3 parts of latent curing accelerator boron trifluoride ethylamine complex is added under the stirring of 20rpm, and then dispersed at 500rpm for 2 hours, and cooling by introducing cold water, ensuring that the temperature of the mixture is lower than 30 ℃, finally stirring and defoaming for 2 hours in vacuum under 50-100Pa, removing the vacuum, filtering by using a 80-mesh steel wire mesh to obtain the low-viscosity single-component epoxy resin composition, and barreling the low-viscosity single-component epoxy resin composition. The performance parameters of the epoxy resin composition obtained are shown in Table 1.
Example 4
20 parts of tetrafunctional glycidyl amine epoxy resin (MY 721) with the epoxy equivalent of 115 g/equivalent and the viscosity of 5000cps at 50 ℃, 1 part of butanediol diglycidyl ether serving as epoxy diluent, 40 parts of chopped glass fiber with the filler particle size of 30 microns, and liquid methyl30 parts of nadic anhydride and 2 parts of thixotropic auxiliary agent, and the specific surface area of the modified dimethyl silicone fluid is 100m2/g hydrophobic fumed silica CAB-O-
TS-720 and 0.01 part of organic silicon defoamer are added into a mixing kettle, high-speed dispersion is carried out for 3 hours at 1000rpm, cooling water is introduced to control the temperature of the mixture to be lower than 40 ℃, high-speed dispersion is stopped, stirring is carried out at 20rpm, 3 parts of latent curing accelerator acetylacetone aluminum metal complex are added under stirring at 20rpm, then stirring is carried out for 2 hours at 20rpm, cooling water is introduced to ensure that the temperature of the mixture is lower than 30 ℃, finally, vacuum stirring and defoaming are carried out for 2 hours at 50-100Pa, after vacuum is relieved, filtering is carried out by using a 80-mesh steel wire mesh, and then the low-viscosity single-component epoxy resin composition is obtained and is barreled. The performance parameters of the epoxy resin composition obtained are shown in Table 1.
Example 5
20 parts of phenol novolac polyglycidyl ether (viscosity 5000cps @66 ℃) with epoxy equivalent of 180 g/equivalent, 10 parts of bisphenol F type epoxy resin (NPEF-170) with epoxy equivalent of 170 g/equivalent and viscosity of 3500cps at 25 ℃, 1 part of epoxy diluent butanediol diglycidyl ether, 40 parts of glass powder with filler particle size of 30 microns, 20 parts of liquid methylnadic anhydride, 3 parts of organic thixotropy auxiliary agent, high molecular weight polyurea compound BYK-415 and 0.01 part of organic silicon defoamer are added into a mixing kettle, high-speed dispersion is carried out for 3 hours at 1000rpm, the temperature of the mixture is controlled to be lower than 40 ℃ by cooling water, the high-speed dispersion is stopped, stirring is carried out at 20rpm, 3 parts of latent curing accelerator boron trifluoride ethylamine complex is added under stirring at 20rpm, then stirring and dispersing are carried out for 2 hours at 20rpm, and cooling by introducing cold water, ensuring that the temperature of the mixture is lower than 30 ℃, finally stirring and defoaming for 2 hours in vacuum under 50-100Pa, removing the vacuum, filtering by using a 80-mesh steel wire mesh to obtain the low-viscosity single-component epoxy resin composition, and barreling the low-viscosity single-component epoxy resin composition. The performance parameters of the epoxy resin composition obtained are shown in Table 1.
Comparative example 1
Example 1 was repeated, but 3 parts of the hydrophilic fumed silica of example 1 were removed from the thixotropic adjuvant and the performance parameters of the resulting composition are given in Table 1.
Physical property detection
The single-component epoxy resin compositions of examples 1 to 5 and comparative example 1 and the commercially available high-viscosity epoxy encapsulating compound were subjected to various physical property index tests, and the test results are shown in table 1.
TABLE 1 Main physical Property indices of one-component epoxy resin compositions of examples 1 to 5 and comparative example 1 and commercially available high-viscosity epoxy encapsulating adhesive
And (3) uniformly coating 20g of the epoxy resin composition on a 60 × 120mm silicon steel sheet, vertically placing the silicon steel sheet in an oven at 150 ℃ for baking for 1 hour to solidify the resin, taking out the silicon steel sheet for cooling, measuring the film thickness at the geometric center of the coating, and measuring the film thickness by using a film thickness gauge.
Note: three Bond 2286D one-component epoxy composition
As can be seen from Table 1, the low viscosity one-component epoxy resin compositions of examples 1-5 have significantly reduced viscosity compared to the commercially available high viscosity epoxy encapsulating compound, and are suitable for dispensing by a peristaltic pump, wherein the film thickness in vertical planes after curing is about 0.5-1.0mm, which is suitable for rotor surface encapsulation. The cured performance is similar to the index of the high-viscosity epoxy encapsulating adhesive, and the requirements of high-speed and high-vibration rotor encapsulation can be met. The comparative example 1 shows that the viscosity of the epoxy resin composition without the thixotropic auxiliary agent is greatly reduced, and the film-forming thickness is very thin, so that the film-forming thickness requirement of the encapsulating adhesive cannot be met.
Storage stability testing
The viscosities of examples 1-5, comparative example 1, and the high viscosity epoxy resin-coated sealants were measured after storing the sealants at 25 ℃ for 60 days. As shown in the table I, the epoxy resin compositions of examples 1-5 showed only a small increase in viscosity, while the comparative high viscosity epoxy encapsulating compound showed a significant increase, indicating better product stability. Then, the film-forming thickness, i.e., the vertical surface drying thickness of the silicon steel sheet shown in table 1, was measured. The film-forming thicknesses of the epoxy resin compositions of examples 3 and 4 were not substantially changed, and the film-forming thicknesses of the epoxy resin compositions of examples 1, 2, 5 and comparative example 1 were slightly decreased.
Example 6-use of the Low viscosity epoxy resin composition of the invention and the epoxy resin composition of comparative example 1 as a rotor encapsulant
The encapsulation procedure was as follows: on an automatic paint dripping machine, the rotation speed of the rotor is adjusted to 30rpm, the rotor of an angle grinder is preheated to 80-90 ℃, about 10g of the epoxy resin composition from example 3 is uniformly dripped on a hook and a neck of a rotor commutator to serve as an encapsulating adhesive, then the epoxy resin composition is baked for 20 minutes at 120 ℃ under continuous rotation, and is baked for 40 minutes at 140 ℃ after the rotation is stopped. The resulting encapsulated rotor is illustrated in figure 1 and in cross-section in figure 2.
The above encapsulation procedure was repeated using the epoxy resin composition from example 1 as the encapsulating glue. The picture of the resulting encapsulated rotor is shown in figure 3.
The encapsulation procedure described above was repeated using the epoxy resin composition from comparative example 1 as the encapsulating glue. The resulting encapsulated rotor is illustrated in figure 4.
As can be seen from the figure, the epoxy resin of the embodiment 1 and the embodiment 3 is used as the encapsulating glue to completely encapsulate the wiring position of the rotor, and the surface is smooth without concave-convex defects. The section shows that the encapsulating glue completely permeates the interior of the copper wire, and no pore crack exists in the glue. Fully meets the performance requirements of the rotor of the electric tool.
However, when the wiring of the rotor was encapsulated with the epoxy resin of comparative example 1 as an encapsulating compound, it was seen from FIG. 4 that the film was thin and the wires were exposed.
Claims (19)
1. A one-part epoxy resin composition comprising at least one epoxy resin, at least one liquid anhydride curing agent, at least one curing accelerator, and at least one thixotropic adjuvant.
2. The one-component epoxy resin composition according to claim 1, wherein the epoxy resin is selected from one or more of bisphenol a type epoxy resin, bisphenol F type epoxy resin, phenol aldehyde type epoxy resin and glycidyl amine type epoxy resin which are liquid at room temperature.
3. The one-component epoxy resin composition according to claim 1 or 2, wherein the viscosity of the epoxy resin is 2000-15000cps, preferably 3000-12000cps, at 25 ℃ and/or 3000-7000cps, preferably 4000-6000cps, at 50 or 66 ℃ and/or the epoxy equivalent of the epoxy resin is 80-250 g/equivalent, preferably 100-200 g/equivalent.
4. A one-component epoxy resin composition according to any one of claims 1 to 3, wherein the epoxy resin is used in an amount of 15 to 60 parts by weight, preferably 20 to 40 parts by weight, based on 100 parts by weight of the one-component epoxy resin composition.
5. The one-component epoxy resin composition according to any one of claims 1 to 4, wherein the liquid anhydride curing agent is selected from one or more of methyl hexahydrophthalic anhydride, methyl tetrahydrophthalic anhydride and methyl nadic anhydride.
6. The one-part epoxy resin composition according to any one of claims 1 to 5, wherein the liquid acid anhydride curing agent is used in an amount of 15 to 60 parts by weight, preferably 20 to 40 parts by weight, based on 100 parts by weight of the one-part epoxy resin composition.
7. The one-component epoxy resin composition according to any one of claims 1 to 6, wherein the cure accelerator is a latent cure accelerator, preferably the cure accelerator is selected from one or more of imidazole-type accelerators, microcapsule-encapsulated imidazole-type accelerators, organozinc-type accelerators, boramine-type accelerators and titanates having a melting point above 150 ℃.
8. The one-component epoxy resin composition according to any one of claims 1 to 7, wherein the thixotropy auxiliary is selected from one or more of fumed silica, organobentonite and organothixotropic agents, preferably fumed silica and organobentonite, more preferably hydrophobically modified fumed silica.
9. The process according to claim 8, wherein the hydrophobically modified fumed silica is selected from silane-modified hydrophobic fumed silicas and polysiloxane-modified hydrophobic fumed silicas, preferably polysiloxane-modified hydrophobic fumed silicas.
10. The one-component epoxy resin composition according to claim 8, wherein the fumed silica has an average particle size of 8 to 100nm, preferably 10 to 50nm, most preferably 10 to 20 nm.
11. The one-component epoxy resin composition according to claim 8, wherein the organobentonite thixotropic agent is an oily organobentonite thixotropic agent of 200-3000 mesh, more preferably an organobentonite thixotropic agent which does not require pre-gel activation, and/or the organothixotropic agent is a polyurea compound.
12. The one-component epoxy resin composition according to any one of claims 1 to 11, wherein the thixotropy promoter is used in an amount of 1 to 8 parts by weight, preferably 2 to 5 parts by weight, based on 100 parts by weight of the one-component epoxy resin composition.
13. The one-component epoxy resin composition according to any one of claims 1 to 12, further comprising an epoxy diluent, preferably the epoxy diluent is selected from one or more of the glycidyl ethers of diols and triols which are liquid at room temperature.
14. The one-component epoxy resin composition according to any one of claims 1 to 13, further comprising a filler and a defoamer.
15. The one-component epoxy resin composition according to any one of claims 1 to 14, wherein the viscosity of the one-component epoxy resin composition is from 30 to 120Pas, preferably from 40 to 100Pas, and/or the shore D hardness of the one-component epoxy resin composition after curing is from 85 to 95, and/or the glass transition temperature of the one-component epoxy resin composition after curing is from 120-.
16. The one-component epoxy resin composition according to any one of claims 1 to 15, comprising the following components in parts by weight, based on 100 parts by weight of the one-component epoxy resin composition:
20 to 40 parts by weight of an epoxy resin,
20-40 parts by weight of an acid anhydride curing agent,
0.8 to 5 parts by weight of a curing accelerator,
2-5 parts by weight of a thixotropic auxiliary agent,
1 to 5 parts by weight of an epoxy diluent,
20 to 50 parts by weight of a filler, and
0.01-0.5 weight portion of defoaming agent.
17. A method of preparing the one-part epoxy resin composition of any one of claims 1-16, comprising the steps of:
1) mixing and uniformly dispersing the components of the single-component epoxy resin composition except the curing accelerator; and
2) the curing accelerator is added and uniformly dispersed at a temperature of the mixture of not more than 30 ℃, preferably not more than 25 ℃ to obtain the one-component epoxy resin composition.
18. A method of curing a one-component epoxy resin composition as defined in any one of claims 1 to 16, which comprises applying the one-component epoxy resin composition to a surface of a workpiece and then baking at 130-150 ℃ for 30-60 minutes.
19. Use of the one-component epoxy resin composition as defined in any one of claims 1 to 16 as an encapsulant, in particular as an encapsulant for rotors, especially in the encapsulation of the necks of rotors of electric tools.
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| CN201811591735.0A CN111349415A (en) | 2018-12-20 | 2018-12-20 | Single-component epoxy resin composition and preparation method thereof |
| CN201980057523.0A CN112654675A (en) | 2018-12-20 | 2019-12-19 | Single-component epoxy resin composition and preparation method thereof |
| PCT/CN2019/126630 WO2020125715A1 (en) | 2018-12-20 | 2019-12-19 | Mono-component epoxy resin composition and preparation method therefor |
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| CN111793481A (en) * | 2020-06-12 | 2020-10-20 | 中国石油天然气集团公司 | Resin cementing material for oil-gas well as preparation method and application thereof |
| CN113583384A (en) * | 2021-07-19 | 2021-11-02 | 浙江工业大学 | Preparation method of epoxy resin @ magnetic powder microcapsule integrated inductance material |
| CN115232444A (en) * | 2022-09-02 | 2022-10-25 | 重庆大学 | High-thermal-conductivity spherical boron nitride composite epoxy resin and preparation method thereof |
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| CN116751547A (en) * | 2023-04-26 | 2023-09-15 | 湖北三选科技有限公司 | Preparation method of mold compound, mold compound and semiconductor chip |
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| CN1125488C (en) * | 2000-08-25 | 2003-10-22 | 中国科学院化学研究所 | Liquid epoxy composite for packaging semiconductor and its application |
| JP2005220306A (en) * | 2004-02-09 | 2005-08-18 | Kyocera Chemical Corp | One pack type epoxy resin composition for electric insulation and electric part device |
| JP5221051B2 (en) * | 2007-03-30 | 2013-06-26 | ソマール株式会社 | One-pack type epoxy resin composition, insulation coil using the composition, and method for producing cured fiber structure |
| WO2012014499A1 (en) * | 2010-07-29 | 2012-02-02 | 三井化学株式会社 | Composition, composition being for end-face sealing agent for display devices and consisting of the composition, display devices, and process for producing same |
| CN102010576A (en) * | 2010-09-11 | 2011-04-13 | 汕头市骏码凯撒有限公司 | Repairable type epoxy resin encapsulating glue and preparation method thereof |
| JP6085130B2 (en) * | 2012-09-07 | 2017-02-22 | 旭化成株式会社 | Liquid resin composition and processed product |
| CN102827566B (en) * | 2012-09-19 | 2014-03-05 | 三友（天津）高分子技术有限公司 | Single-component high/low-temperature-resistant epoxy resin composition |
| CN103013411B (en) * | 2012-12-26 | 2013-11-13 | 赛伦（厦门）新材料科技有限公司 | Insulated and heat-conducting film adhesive and preparation method thereof |
| CN103333467A (en) * | 2013-06-20 | 2013-10-02 | 湖北三江航天江北机械工程有限公司 | Epoxy resin composition for filament winding and preparation method thereof |
| US10233295B2 (en) * | 2014-04-15 | 2019-03-19 | Mitsubishi Gas Chemical Company, Inc. | Fiber-reinforced composite material |
| CN107641292A (en) * | 2016-07-27 | 2018-01-30 | 惠柏新材料科技（上海）股份有限公司 | A kind of composition epoxy resin for fiber winding and preparation method thereof |
| CN106281171B (en) * | 2016-09-07 | 2019-08-06 | 深圳先进技术研究院 | A kind of epoxy resin soldering flux, preparation method and application |
| CN106987094A (en) * | 2017-04-01 | 2017-07-28 | 泰山体育产业集团有限公司 | A kind of epoxy-resin systems and preparation method thereof |
| CN108314984A (en) * | 2018-02-05 | 2018-07-24 | 深圳市鑫东邦科技有限公司 | A kind of one-component high-temp glue and preparation method thereof |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111793481A (en) * | 2020-06-12 | 2020-10-20 | 中国石油天然气集团公司 | Resin cementing material for oil-gas well as preparation method and application thereof |
| CN113583384A (en) * | 2021-07-19 | 2021-11-02 | 浙江工业大学 | Preparation method of epoxy resin @ magnetic powder microcapsule integrated inductance material |
| CN115232444A (en) * | 2022-09-02 | 2022-10-25 | 重庆大学 | High-thermal-conductivity spherical boron nitride composite epoxy resin and preparation method thereof |
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| WO2020125715A1 (en) | 2020-06-25 |
| CN112654675A (en) | 2021-04-13 |
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