阅读说明：本技术 一种酸酐可固化有机硅改性环氧树脂灌封胶及其制备方法 (Anhydride-curable organic silicon modified epoxy resin pouring sealant and preparation method thereof ) 是由 黄灵智 杨秀生 安秋凤 于 2021-10-18 设计创作，主要内容包括：本发明公开了一种酸酐可固化有机硅改性环氧树脂灌封胶及其制备方法,该灌封胶由A、B两组分所组成,A组分包括环氧树脂、聚合度为2-8的2-4官能环氧基低聚硅氧烷、聚合度为4的1-2官能环氧基/烃酯基改性的环状低聚硅氧烷、活性环氧稀释剂、纳米颜填料、分散剂等；而B组分为酸酐固化剂。本发明的有机硅改性环氧树脂灌封胶,可克服市售聚硅氧烷遇环氧树脂易出现的浑浊、分层现象,在120-150℃受热后可实现胶层固化。与未改性环氧灌封胶相比,本发明有机硅改性的环氧树脂灌封胶,柔韧性、断裂伸长率与耐冲击性增加、抗老化性能增强,胶层表面水的接触角可达到89-112°,表明胶层有较好的防水防潮效果。(The invention discloses an anhydride curable organosilicon modified epoxy resin pouring sealant and a preparation method thereof, wherein the pouring sealant consists of A, B two components, wherein the component A comprises epoxy resin, 2-4 functional epoxy group oligosiloxane with the polymerization degree of 2-8, 1-2 functional epoxy group/hydrocarbon ester group modified cyclic oligosiloxane with the polymerization degree of 4, active epoxy diluent, nano pigment and filler, dispersant and the like; and the component B is an anhydride curing agent. The organic silicon modified epoxy resin pouring sealant can overcome the turbidity and delamination phenomena of the commercially available polysiloxane when meeting epoxy resin, and can realize the curing of a glue layer after being heated at the temperature of 120-plus-150 ℃. Compared with unmodified epoxy pouring sealant, the organic silicon modified epoxy resin pouring sealant has the advantages of increased flexibility, elongation at break and impact resistance, enhanced aging resistance, and contact angle of water on the surface of the adhesive layer of 89-112 degrees, which shows that the adhesive layer has better waterproof and moistureproof effects.)

1. The anhydride-curable organic silicon modified epoxy resin pouring sealant is characterized by comprising the following components in percentage by mass:

the component A comprises 100 parts of organic silicon modified epoxy resin, 0-20 parts of active epoxy diluent, 0.5-1.0 part of dispersant and 25-50 parts of nano pigment filler; and the number of the first and second groups,

the component B is an anhydride curing agent which is anhydride or oligomer with 1-2 anhydride groups connected in the molecule;

the organic silicon modified epoxy resin comprises 50-85 parts of epoxy resin, 5-25 parts of 2-4 functional epoxy group oligosiloxane with the polymerization degree of 2-8 and 10-25 parts of 1-2 functional epoxy group/hydrocarbon ester group modified cyclic oligosiloxane with the polymerization degree of 4;

the 2-4 functional epoxy group oligosiloxane with the polymerization degree of 2-8 is linear, annular or cage oligosiloxane with the molecular containing 2-4 epoxy groups and the polymerization degree of Si-O bond of 2-8;

the 1-2 functional epoxy group/hydrocarbon ester group modified cyclic oligosiloxane with the polymerization degree of 4 is a cyclic oligosiloxane with 1-2 epoxy groups and 2-3 hydrocarbon ester groups X connected in the molecule, and the structural formula is as follows:

in the formula, X is alkyl ester group, phenethylene group or C8-18 alkyl group, and the structural formula of the alkyl ester group is CH₂CHMCOOR，M＝H、CH₃，R＝-CH₃～-C₁₈H₃₇(ii) a EP is one of 2, 3-epoxypropoxypropyl, 3, 4-epoxycyclohexylethyl and 2, 3-epoxypropoxypolyetherpropyl;

the active epoxy diluent is a compound or polymer which contains 1-2 epoxy groups in molecules, can participate in the specific chemical reaction of the epoxy groups and can play a role in dilution.

2. The potting adhesive of claim 1, wherein the 2-4 functional epoxy-oligosiloxane having a degree of polymerization of 2-8 is α, ω -bis (2, 3-glycidoxypropyl) tetramethyldisiloxane, α, ω -bis (3, 4-epoxycyclohexylethyl) tetramethyldisiloxane, α, ω -bis (2, 3-epoxypropoxypolylpolylpropyl) tetramethyldisiloxane, 1,3,5, 7-tetrakis (2, 3-epoxypropoxypropyl) tetramethylcyclotetrasiloxane, 1,3,5, 7-tetrakis (3, 4-epoxycyclohexylethyl) tetramethylcyclotetrasiloxane, 1,3,5, 7-tetrakis (2, 3-epoxypropoxypolylpropyl) tetramethylcyclotetrasiloxane, caged bis (3, 4-epoxycyclohexylethyl) hexaphenyl POSS, One or more caged tris (3, 4-epoxycyclohexylethyl) pentaphenyl POSS.

3. The potting adhesive of claim 1, wherein the 1-2 functional epoxy/hydrocarbon ester modified cyclic oligosiloxane having a degree of polymerization of 4 is 1-epoxy-3, 5, 7-trihydrocarbyl-1, 3,5, 7-tetramethylcyclotetrasiloxane, 1-epoxy-3, 5, 7-trialkoxy-1, 3,5, 7-tetramethylcyclotetrasiloxane, 1, 3-diepoxy-5, 7-dihydrocarbyl-1, 3,5, 7-tetramethylcyclotetrasiloxane, 1, 3-diepoxy-5, 7-dialkyi-1, 3,5, 7-tetramethylcyclotetrasiloxane, 1, 5-diepoxy-3, 7-dihydrocarbyl-1, 3,5, 7-tetramethylcyclotetrasiloxane and 1, 5-diepoxy-3, 7-dialkyl ester-1, 3,5, 7-tetramethylcyclotetrasiloxane.

4. The potting adhesive of claim 1, wherein the 1-2 functional epoxy/hydrocarbyl modified cyclic oligosiloxane having a degree of polymerization of 4 is obtained by a process comprising:

carrying out hydrosilylation addition reaction on tetramethylcyclotetrasiloxane with Si-O bond polymerization degree of 4 and alkenyl epoxy compound, alpha-olefin or alpha-alkenyl ester to obtain 1-2 functional epoxy group/hydrocarbon ester group modified cyclic oligosiloxane with polymerization degree of 4;

the alkenyl epoxy compound is one of allyl glycidyl ether, 1, 2-epoxy-4-vinylcyclohexane and allyl polyether epoxy compound; the alpha-olefin is alpha-olefin with 8-18 carbon atoms; the alpha-alkenyl ester is acrylic acid C_1-18Esters or methacrylic acids C_1-18And (3) an ester.

5. The pouring sealant as claimed in claim 1, wherein the epoxy resin has an epoxy equivalent of 0.2-0.59, a viscosity of 2000-; the epoxy resin is one of bisphenol A epoxy resin, bisphenol F epoxy resin, hydrogenated bisphenol A epoxy resin, novolac epoxy resin, glycidyl ether epoxy resin, glycidyl ester epoxy resin and glycidyl ether amine epoxy resin.

6. The pouring sealant according to claim 1, wherein the nano-pigment filler is one of hydrophobic spherical aluminum oxide, hydrophobic aluminum hydroxide, nano-titanium dioxide or calcium carbonate; the dispersant is BYK-ATU or BYK-161.

7. The potting adhesive of claim 1, wherein the reactive epoxy diluent is one of butyl glycidyl ether, aliphatic alkyl glycidyl ether having 12 to 14 carbons, phenyl glycidyl ether, benzyl glycidyl ether, o-tolyl glycidyl ether, diglycidyl ether, 1, 6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, and polypropylene glycol diglycidyl ether.

8. The pouring sealant according to claim 1, wherein the anhydride curing agent is one or more of methyl hexahydrophthalic anhydride, pyromellitic anhydride, polyether bridged dianhydride; the structural formula of the polyether bridging dianhydride is as follows:

wherein R' is-O (C)₂H₄O)_a1-、-O(C₃H₆O)_b1-、-O(C₂H₄O)_a1(C₃H₆O)_b1-or-O [ (CH)₂)₄O]_c-，a₁、b₁C ranges from 1 to 30, when R' contains a₁And b₁When a is₁+b₁＝1-30。

9. The method for preparing the pouring sealant according to any one of claims 1 to 8, characterized by comprising the steps of:

mixing epoxy resin with 2-4 functional epoxy group oligosiloxane with the polymerization degree of 2-8 and 1-2 functional epoxy group/hydrocarbon ester group modified cyclic oligosiloxane with the polymerization degree of 4 to obtain organic silicon modified epoxy resin, and then adding an active epoxy diluent, a nano pigment filler and a dispersing agent to stir and mix uniformly to obtain a component A;

then, weighing the component B according to the molar ratio of the epoxy group contained in the component A to the anhydride group and the carboxyl group contained in the anhydride curing agent of the component B being 1 (1-0.8), and uniformly stirring the component A and the component B to obtain the anhydride curable organosilicon modified epoxy resin potting adhesive.

10. The method for constructing pouring sealant according to any one of claims 1 to 8, characterized by comprising the steps of:

the pouring sealant as claimed in any one of claims 1 to 8 is injected into the site to be constructed, leveled for 30min, and cured by heating to 120 ℃ and 150 ℃ for 30-120min, thereby achieving curing.

Technical Field

The invention belongs to the field of modified epoxy resin pouring sealant, and particularly relates to a preparation method and application of an organic silicon modified epoxy resin pouring sealant prepared based on an organic anhydride curing agent and organic silicon modified epoxy resin.

Background

Epoxy resin has good adhesive force, strong adhesive property, excellent chemical corrosion resistance and good electrical insulation property, so that the epoxy resin has wide application in the aspects of circuit board packaging and sealing, electronic component potting and insulation, corrosion prevention, moisture prevention and the like. The anhydride compound is one of common curing agents of the epoxy resin, and has the characteristics of low volatility, low toxicity, weak skin irritation, excellent electrical property of a cured epoxy resin glue layer, small volume shrinkage and the like. However, due to the limitation of the structure and the curing mode, the epoxy resin potting adhesive cured by the small molecular anhydride still has the defects of strong rigidity, high hardness, poor impact resistance and flexibility of the adhesive layer, and the like, so that the adhesive layer is still easy to crack or the phenomena of detachment of the interface of the encapsulated electronic material, bulging and the like when the adhesive layer is subjected to the action of external stress or the environmental temperature changes.

Polyorganosiloxanes (abbreviated as silicones) having a low glass transition temperature, - (CH)₃)₂The SiO-chain segment is soft and smooth, is used for modifying the epoxy resin, and can obviously improve the defects of hardness, brittleness and the like of the epoxy resin; however, when the traditional polyorganosiloxane is used for modifying epoxy resin, the solubility parameters of the two are relatively different and the mutual solubility is poor, and particularly when the average molecular weight is large or the dosage is large, the polyorganosiloxane and the epoxy resin are easy to separate, so that the modified epoxy resin system is easy to generate turbidity and delamination, which greatly limits the application of organosilicon in the aspect of modifying epoxy resin and needs to be improved.

Disclosure of Invention

In order to overcome the defects of poor flexibility, hardness, brittleness and the like of the existing epoxy resin pouring sealant solidified by the micromolecular anhydride, the invention designs and synthesizes a micromolecule epoxy group organic silicon oligomer, the oligomer is used for modifying epoxy resin and then is subjected to one-step crosslinking reaction by an anhydride curing agent, the problem of poor intersolubility of commercial polysiloxane and epoxy resin can be solved, and the modified epoxy resin pouring sealant with flexibility, corrosion resistance and moisture resistance can be obtained, and the characteristics of large Si-O bond and Si-C bond energy and good ultraviolet resistance in the polysiloxane structure are utilized, the aging resistance effect of the conventional anhydride curing epoxy resin pouring sealant can be improved, and the service life of an electronic component packaged by the epoxy pouring sealant is further prolonged.

Therefore, the invention adopts the following technical scheme:

a preparation method and application of anhydride curable organosilicon modified epoxy resin pouring sealant are disclosed, wherein the organosilicon modified epoxy resin pouring sealant consists of A, B two components; the component A consists of 100 parts by mass of organic silicon modified epoxy resin, 0-20 parts by mass of active epoxy diluent ED and 25-50 parts by mass of nano pigment and filler; the component B is a curing agent containing acid anhydride.

The organosilicon modified epoxy resin consists of 50-85 parts of epoxy resin, 5-25 parts of 2-4 functional epoxy group oligosiloxane with the polymerization degree of 2-8 and 10-25 parts of 1-2 functional epoxy group/hydrocarbon ester group modified cyclic oligosiloxane with the polymerization degree of 4.

The epoxy resin has an epoxy equivalent of about 0.2-0.59 and a viscosity of about 2000-20000mPa.s, and is one of bisphenol A epoxy resin, bisphenol F epoxy resin, hydrogenated bisphenol A epoxy resin, novolac epoxy resin, aliphatic glycidyl ether epoxy resin, aliphatic glycidyl ester epoxy resin, glycidyl ether amine epoxy resin and the like.

The 2-4 functional epoxy group oligosiloxane with the polymerization degree of 2-8 is linear or cyclic oligosiloxane with the polymerization degree of 2-8 and the molecular contains 2-4 epoxy groups and Si-O bonds, and mainly comprises alpha, omega-diepoxy tetramethyldisiloxane with the polymerization degree of 2, 1,3,5, 7-tetracycloepoxy cyclotetrasiloxane with the polymerization degree of 4, cage-shaped diepoxy oligosilsesquioxane (POSS) with the polymerization degree of 8 and cage-shaped triepoxy oligosilsesquioxane (POSS) with the polymerization degree of 8, wherein alpha, omega-bis (2, 3-epoxypropyloxy) tetramethyldisiloxane with the polymerization degree of 2 and Si-O bonds, alpha, omega-bis (3, 4-epoxycyclohexylethyl) tetramethyldisiloxane with the polymerization degree of 2 and Si-O bonds, Alpha, omega-bis (2, 3-glycidoxypropyl) tetramethyldisiloxane having a degree of polymerization of Si-O bond of 2, 1,3,5, 7-tetrakis (2, 3-glycidoxypropyl) tetramethylcyclotetrasiloxane having a degree of polymerization of Si-O bond of 4, 1,3,5, 7-tetrakis (3, 4-epoxycyclohexylethyl) tetramethylcyclotetrasiloxane having a degree of polymerization of Si-O bond of 4, 1,3,5, 7-tetrakis (2, 3-epoxypropoxypolylpropyl) tetramethylcyclotetrasiloxane having a degree of polymerization of Si-O bond of 4, caged bis (3, 4-epoxycyclohexylethyl) hexaphenyls S having a degree of polymerization of Si-O bond of 8, caged tris (3, 4-epoxycyclohexylpropyl) tetramethylcyclotetrasiloxane having a degree of polymerization of Si-O bond of 8Ethyl) pentaphenyl POSS, or mixtures of any two thereof; the polyether base is selected from polyoxyethylene polyoxypropylene ether-O (C)₂H₄O)_a(C₃H₆O)_b-, polyoxyethylene ether-O (C)₂H₄O)_a-or polyoxypropylene Ether-O (C)₃H₆O)_b-wherein a and b are integers of 0,1,2,3 …, and a and b range from 0 to 10, and a + b is 1 to 10.

The 2-4 functional epoxy group oligosiloxane with the polymerization degree of 2-8 can be directly ordered from related manufacturers or prepared by hydrosilylation addition reaction of 2-4 functional hydrogen-containing oligosiloxane with the polymerization degree of 2-8 and alkenyl epoxy compounds such as Allyl Glycidyl Ether (AGE), 1, 2-epoxy-4-vinyl cyclohexane, allyl polyether epoxy compounds and the like; the allyl polyether epoxy compound is allyl polyoxyethylene polyoxypropylene epoxy ether [ CH ]₂＝CHCH₂O(C₂H₄O)_a(C₃H₆O)_bCH₂CH(O)CH₂]Allyl polyoxyethylene epoxy ether [ CH ]₂＝CHCH₂O(C₂H₄O)_a(C₃H₆O)_bCH₂CH(O)CH₂]Or allyl polyoxypropylene epoxy ether [ CH₂＝CHCH₂O(C₃H₆O)_bCH₂CH(O)CH₂]The value ranges of a and b in the formula are the same as above.

The 1-2 functional epoxy/hydrocarbon ester group modified cyclic oligosiloxane with the Si-O bond polymerization degree of 4 has a structure shown in (1) to (3), and is a cyclic oligosiloxane with 1-2 epoxy groups connected in a molecule and 2-3 hydrocarbon ester groups (X) connected in the molecule.

Wherein X is ═ C₈H₁₇～-C₁₈H₃₇Alkyl, phenethylene radical-CH of₂CH₂C₆H₅Or an alkyl ester group CH₂CHMCOOR，M＝H、CH₃，R＝-CH₃～-C₁₈H₃₇(ii) a EP is 2, 3-glycidoxypropyl, 3, 4-epoxycyclohexylethyl, propylpolyoxyethylene polyoxypropylene epoxy ether [ -C ]₃H₆O(C₂H₄O)_a(C₃H₆O)_bCH₂CH(O)CH₂]Wherein the value ranges of a and b are the same as above.

Preferably X-C is represented by the formula (1)₈H₁₇～-C₁₈H₃₇or-CH₂CH₂C₆H₅The monofunctional 1-epoxy-3, 5, 7-trihydrocarbyl-1, 3,5, 7-tetramethylcyclotetrasiloxane of formula (1) has the structure of X ═ CH₂The monofunctional 1-epoxy-3, 5, 7-trialkyl-1, 3,5, 7-tetramethylcyclotetrasiloxane of CHMCOOR has a structure shown as a formula (2) and X ═ C₈H₁₇～-C₁₈H₃₇or-CH₂CH₂C₆H₅The difunctional 1, 3-diepoxy-5, 7-dialkyl-1, 3,5, 7-tetramethylcyclotetrasiloxane of (2), and the structure of X ═ CH₂A difunctional 1, 3-diepoxy-5, 7-dialkyl ester-1, 3,5, 7-tetramethylcyclotetrasiloxane of CHMCOOR, X ═ C as shown in formula (3)₈H₁₇～-C₁₈H₃₇or-CH₂CH₂C₆H₅The difunctional 1, 5-diepoxy-3, 7-dialkyl-1, 3,5, 7-tetramethylcyclotetrasiloxane of (2), the structure of which is shown as formula (3) and X ═ CH₂One or a mixture of any two of difunctional 1, 5-diepoxy-3, 7-dialkyl ester-1, 3,5, 7-tetramethylcyclotetrasiloxane of CHMCOOR; the hydrocarbyl is-C₈H₁₇～-C₁₈H₃₇Alkyl or phenethylene group (-CH) of₂CH₂C₆H₅) Wherein the alkyl ester group is CH₂CHMCOOR, in which M ═ H or CH₃、R＝-CH₃～-C₁₈H₃₇。

The 1-2 functional epoxy/hydrocarbon ester group modified cyclic oligosiloxane with the polymerization degree of 4 is tetramethylcyclotetrasiloxane (D) with the polymerization degree of 4 of Si-O bond₄ ^H) With Alkenyl Epoxides (AE), alpha-olefins or alpha-olefin estersThe hydrosilylation is synthesized; the alkenyl epoxy compound (AE) is one of allyl glycidyl ether, 1, 2-epoxy-4-vinyl cyclohexane and allyl polyether epoxy compound; the alpha-olefin is mainly alpha-C_8-18Olefin, which is one of alpha-octene, alpha-dodecene, alpha-hexadecene, alpha-octadecene or styrene; the alpha-alkenyl ester is mainly a compound containing alkenyl and ester group in the molecular structure, and acrylic acid C is selected_1-18Esters, methacrylic acid C_1-18One of esters, etc., preferably (meth) acrylic acid C_4-18An ester; the allyl polyether epoxy compound is one of allyl polyoxyethylene polyoxypropylene epoxy ether, allyl polyoxypropylene epoxy ether and allyl polyoxyethylene epoxy ether which have the same structure as the allyl polyoxyethylene polyoxypropylene epoxy ether.

The active Epoxy Diluent (ED) is a compound or polymer which contains 1-2 epoxy groups in the molecule, can participate in the specific chemical reaction of the epoxy groups and can play a role of diluting similar solvents, and butyl glycidyl ether and C are selected_12-14Aliphatic alkyl glycidyl ether, phenyl glycidyl ether, benzyl glycidyl ether, o-tolyl glycidyl ether, diglycidyl ether [ also known as bis (2, 3-epoxypropyl) ether ]]1, 6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, polypropylene glycol diglycidyl ether, and the like.

The filler is an inorganic filler with heat conduction and flame retardant effects, and is prepared from hydrophobic spherical aluminum oxide and hydrophobic aluminum hydroxide Al (OH)₃One of nano titanium dioxide or calcium carbonate; the dispersant is BYK-ATU or BYK-161.

The component B is a micromolecular anhydride compound or oligomer with 1-2 anhydride groups connected in the molecule, and one or a mixture of any two of methyl hexahydrophthalic anhydride, pyromellitic dianhydride, polyether bridging dianhydride (CBA) and the like is selected; the polyether bridging dianhydride curing agent has a structure shown in a formula (4), and is prepared by esterification reaction of pyromellitic dianhydride and polyether glycol according to reference CN112679704, wherein R' is a polyether group, and polyoxyethylene ether-O (C) is selected₂H₄O)_a1-, polyoxypropylene Ether group-O (C)₃H₆O)_b1-, polyoxyethylene polyoxypropylene Ether group-O (C)₂H₄O)_a1(C₃H₆O)_b1-or polytetrahydrofuran ether-O [ (CH)₂)₄O]_c-one of the following, wherein a₁、b₁C is an integer of 1,2,3 …, a₁、b₁C is in the range of 0-30, a₁+b₁＝1-30。

The dosage of the anhydride curing agent in the component B is controlled as follows: number of moles of epoxy groups contained in system a component: the mole number of (anhydride group + carboxyl group) in the component B acid anhydride curing agent is about 1:1 to 0.8.

The preparation method of the anhydride curable organosilicon modified epoxy resin pouring sealant comprises the following steps: weighing epoxy resin, 2-4 functional epoxy group oligosiloxane with Si-O bond polymerization degree of 2-8 and 1-2 functional epoxy group/hydrocarbon ester group modified cyclic oligosiloxane with Si-O bond polymerization degree of 4 in sequence according to parts by mass, stirring and uniformly mixing to obtain organic silicon modified epoxy resin, then adding active epoxy diluent, nano filler, dispersant and the like in proportion, stirring and dispersing for 30-60min by using a high-speed dispersion machine with the rotation speed of 1000-1500r/min, vacuumizing and defoaming to obtain a mixture, and marking the mixture as a component A;

then, based on the mole number of epoxy groups contained in component a: and (3) weighing the component B, namely the anhydride curing agent, in the component B anhydride curing agent (anhydride group + carboxyl group) in a molar ratio of 1:1-0.8, uniformly stirring the component A and the component B, vacuumizing and defoaming to obtain a mixture, namely the anhydride curable organosilicon modified epoxy resin potting adhesive.

The application steps of the anhydride curable organosilicon modified epoxy resin pouring sealant are as follows: pouring the anhydride curable organic silicon modified epoxy resin pouring sealant into the surface of an electronic component or a circuit board, leveling for 30min at room temperature, heating to 120-150 ℃ for curing for 30-120min, and obtaining a sample, namely the cured organic silicon modified epoxy resin pouring sealant test sample.

The application of the anhydride curable organic silicon modified epoxy resin pouring sealant comprises the application of the pouring sealant in the aspects of circuit board and electrical appliance element packaging, potting, sealing, related fields and the like.

The application performance of the anhydride curable organosilicon modified epoxy resin pouring sealant is evaluated by the following method: shore A hardness is determined by a TIME5430 digital Shore A durometer according to GB/T531-1999; the elongation at break is determined by a universal tensile machine according to the GB/T1040.1-2006 method; impact resistance: spraying anhydride curable organic silicon modified epoxy resin pouring sealant on the surface of the tinplate for sample preparation according to a coating method, then curing the pouring sealant with the pouring sealant method, and determining the sample by using an impact resistant device according to a GB/T1732-1993 method; flexibility of the glue layer: preparing a sample according to a coating method, and measuring by using an QTX type paint film flexibility measuring instrument; aging resistance: the test temperature is 85 ℃, the relative humidity RH is controlled to be 85 percent and the test time is 1000h when the test is measured by using a KK-SN-150 xenon lamp aging-resistant test box according to the GB/T2423.24-1995 standard. The waterproof performance of the surface of the adhesive layer is as follows: the contact angle (WCA) of water on the surface of the adhesive layer shows that the water drop size is 5 muL by using a JC-2000C1 type static contact angle measuring instrument, and the larger the WCA is, the better the water repellency and the better the moisture resistance of the surface of the adhesive layer are.

The invention has the beneficial effects that: according to the invention, the characteristics of good intersolubility and no phase separation of epoxy-based oligosiloxane and epoxy resin are fully utilized, firstly, oligosiloxane (ESi-1) with 2-4 epoxy groups in a molecular structure and with a Si-O bond polymerization degree of 2-8, epoxy/hydrocarbon ester-based modified cyclic oligosiloxane (ESi-2) with 1-2 epoxy groups in a molecular structure and a Si-O bond polymerization degree of 4 are blended with epoxy resin to prepare uniform-phase organic silicon modified epoxy resin, and then the epoxy resin is crosslinked and cured by curing agents such as methyl hexahydrophthalic anhydride, polyether bridging dianhydride and the like, so that the problems of phase separation, turbidity and the like easily generated when the traditional polysiloxane macromolecules are used for modifying the epoxy resin can be solved, and thus the transparent and uniform phases of the organic silicon modified epoxy potting adhesive are realized; secondly, the invention skillfully utilizes the low glass transition temperature of polysiloxane and siloxane chain segment- [ (CH)₃)₂SiO]The oligomer ESi-1 is uniformly introduced and bonded in an epoxy resin system, so that the problems of poor flexibility of the epoxy resin, hard and brittle glue layer after curing, easy cracking in use and the like are solved; the epoxy group/long-chain hydrocarbon ester group modified cyclic oligosiloxane ESi-2 is introduced into an epoxy resin system, and the surface energy of the ESi-2 structure is utilized to modify the low-long-chain hydrocarbon group such as C_8-18The alkyl, the phenylethynyl, the alkyl ester group and the like are directionally arranged by heating and cover the surface of the epoxy resin, and the ultraviolet resistance, the water resistance and the moisture resistance of the epoxy resin can be effectively improved, so that the glue layer is not easy to age, and the purpose of prolonging the service life of electronic components packaged by the epoxy resin is further achieved.

The organic silicon modified epoxy resin pouring sealant prepared by the invention can overcome the turbidity and delamination phenomena of the commercially available polysiloxane when meeting epoxy resin, and can realize the curing of a glue layer after being heated at the temperature of 120-plus-150 ℃. Compared with unmodified epoxy pouring sealant, the organic silicon modified epoxy resin pouring sealant has the advantages of increased flexibility, elongation at break and impact resistance, enhanced aging resistance, and contact angle of water on the surface of the adhesive layer of 89-112 degrees, which shows that the adhesive layer has better waterproof and moistureproof effects.

Detailed Description

The present invention will be further described with reference to the following examples, but the present invention is not limited to the following examples. Preparation of 1-2 functional epoxy/hydrocarbon ester group-modified cyclic oligosiloxanes having degree of polymerization of 4

0.1mol of tetramethylcyclotetrasiloxane (D) is added into a three-necked flask provided with a thermometer, a reflux condenser tube and a stirrer in sequence according to the metering ratio₄ ^H) 1/3-1/5 molar total amount of alkenyl epoxy compound AE and alpha-olefin or alpha-alkenyl ester, stirring and mixing uniformly, heating to 80 ℃, adding 20-30ppm of complex platinum catalyst KP22, stirring for 3-5min until the system starts to release heat, then beginning to dropwise add the rest amount of the mixture of AE and alpha-olefin or alpha-alkenyl ester, controlling the dropwise adding speed to maintain the reaction temperature of the system at 80-90 ℃, after the dropwise adding is finished, adding a proper amount of KP22, continuing to control the temperature to 80-90 ℃, stirring and reacting for 4h, then controlling the temperature at 120 ℃ and P at P, wherein the temperature is controlled to be between 80 and 90 ℃, and stirring and reacting for 4h_{Watch (A)}About 0.08 (gauge pressure)Reducing pressure and removing low boiling point under the condition of 0.09MPa to obtain colorless-light yellow transparent liquid, namely 1-2 functional epoxy group/hydrocarbon ester group modified cyclic oligosiloxane (ERS) with the polymerization degree of Si-O bonds of 4 and the structure shown in formulas (1) to (3). The raw material amounts of the epoxy/hydrocarbon ester-based modified cyclic oligosiloxanes synthesized in the examples of the present invention are summarized in Table 1.

TABLE 1 tabulated amount of epoxy/hydrocarbon ester-based modified cyclic oligosiloxane raw material prepared in the examples

AGE: allyl glycidyl ether; AH 307030: allyl polyoxypropylene epoxy ether having Mn 300 and b 3; EVCH: 1, 2-epoxy-4-vinylcyclohexane

Example II

Example 1

According to the parts by mass, 85.0g of bisphenol A epoxy resin E-51 with the epoxy equivalent of about 0.51 and the viscosity of about 11000mPa.s, 5.0g of 1,3,5, 7-tetra (2, 3-epoxypropoxypropyl) tetramethylcyclotetrasiloxane with the polymerization degree of Si-O bond of 4, 10.0g of X ═ C with the polymerization degree of Si-O bond of 4 and the structure shown in formula (2) are weighed in sequence₈H₁₇The mixture of difunctional 1, 3-bis (2, 3-glycidoxypropyl) -5, 7-dioctyl-1, 3,5, 7-tetramethylcyclotetrasiloxane having EP 2, 3-glycidoxypropyl group and difunctional 1, 5-bis (2, 3-glycidoxypropyl) -3, 7-dioctyl-1, 3,5, 7-tetramethylcyclotetrasiloxane having the structure represented by the formula (3) was stirred and mixed to obtain 100.00g of silicone-modified epoxy resin in total, 10.0g of butyl glycidyl ether, 0.5g of BYK-ATU dispersant and 25.0g of Al₂O₃Stirring and dispersing for 30min by a dispersion machine with the rotating speed of 1500r/min, and then performing P_{Watch (A)}Vacuumizing and defoaming under the condition of 0.7MPa for 10min, and recording the obtained mixture as A1 component.

Then, based on the number of moles of epoxy groups contained in the a1 component: in the component B1, the mole number of (anhydride groups + carboxyl groups) in the anhydride curing agent is 1:1, then 95.52g of methyl hexahydrophthalic anhydride curing agent (B1) is weighed, A1 and B1 are stirred and mixed uniformly, and the obtained mixture is the anhydride curable organosilicon modified epoxy potting adhesive, which is marked as ASE-1.

Example 2

According to the mass parts, 50.0g of bisphenol A epoxy resin E-44 with the epoxy equivalent of about 0.44 and the viscosity of about 20000mPa.s, 25.0g of alpha, omega-bis (2, 3-epoxypropoxypropyl) tetramethyldisiloxane with the polymerization degree of Si-O bond of 2, 25.0g of X ═ C with the polymerization degree of Si-O bond of 4 and the structure shown in formula (1) are weighed in sequence₁₈H₃₇And EP 1- (3, 4-epoxycyclohexylethyl) -3,5, 7-trioctadecyl) -1,3,5, 7-tetramethylcyclotetrasiloxane of 3, 4-epoxycyclohexylethyl, stirring and uniformly mixing to obtain 100.00g of organosilicon modified epoxy resin, then adding 1.0g of BYK-ATU dispersing agent and 50.0g of nano TiO₂Stirring and dispersing for 60min by a high-speed dispersion machine with the rotating speed of 1000r/min, and then performing P_{Watch (A)}Vacuumizing and defoaming for 30min under the condition of 0.7MPa, and recording the obtained mixture as A2 component.

Then, based on the number of moles of epoxy groups contained in the a2 component: the molar number of (anhydride group + carboxyl group) in the anhydride curing agent of component B2 was about 1:0.8, and 80.97g of an acid anhydride curing agent having a structure represented by formula (4) and R' ═ O (C)₃H₆O)₃The curing agent B2 of polyoxypropylene ether bridged dianhydride CBA with the solid content of 59.03 percent and the content of (carboxyl + anhydride) of 0.6364 percent is stirred and evenly mixed with A2 and B2 to obtain a mixture, namely the anhydride curable organosilicon modified epoxy potting adhesive, which is marked as ASE-2.

Example 3

According to parts by mass, 70.0g of novolac epoxy resin F-51 with the epoxy equivalent of about 0.59 and the viscosity of about 12000mPa.s, 15.0g of caged bis (3, 4-epoxycyclohexylethyl) hexaphenyl POSS with the Si-O bond polymerization degree of 8, 15.0g of caged bis (3, 4-epoxycyclohexylethyl) hexaphenyl POSS with the Si-O bond polymerization degree of 4 and the structure shown as the formula (1) X ═ CH₂CH₂C₆H₅Stirring and mixing (phenylethynyl) and EP (epoxy polyoxypropylene) propyl mono-functional 1- (epoxy polyoxypropylene propyl) -3,5, 7-tri (phenylethynyl) -1,3,5, 7-tetramethylcyclotetrasiloxane with b being 3 to obtain 100.00g of total organic silicon modified epoxy resin, then adding 10.0g of polypropylene glycol diglycidyl ether (epoxy equivalent weight is 320g/eq) active diluent, 0.5g of BYK-ATU dispersant and 25.0g of hydrophobic nano aluminum hydroxide, stirring and mixing uniformly, and then using the rotating speed of 1000Stirring and dispersing for 40min by r/min high-speed disperser, and then dispersing for P_{Watch (A)}Vacuum degassing under 0.7MPa for 20min, and recording the obtained mixture as A3 component.

Then, based on the number of moles of epoxy groups contained in the component of system a 3: the molar number of (anhydride group + carboxyl group) in the anhydride curing agent of the B3 component was about 1:0.8, and 52.58g of methylhexahydrophthalic anhydride and 20.81g of R' ═ O (C) having the structure shown in formula (4) were weighed out₃H₆O)₃And curing agent (B3) consisting of polyoxypropylene ether bridged dianhydride CBA with the solid content of 59.03 percent and the content of (anhydride group + carboxyl group) of 0.6364 percent, stirring and uniformly mixing A3 and B3 to obtain a mixture, namely the anhydride curable organosilicon modified epoxy potting adhesive, which is marked as ASE-3.

Example 4

65.0g of hydrogenated bisphenol A epoxy resin with the epoxy equivalent of about 0.51 and the viscosity of about 8000mPa.s, 5.0g of 1,3,5, 7-tetra (2, 3-glycidoxypropyl) tetramethylcyclotetrasiloxane with the polymerization degree of Si-O bond of about 4, 10.0g of alpha, omega-di (2, 3-glycidoxypropyl) tetramethyldisiloxane (Mn362.61) with the polymerization degree of Si-O bond of 2, 20.0g of Si-O bond with the polymerization degree of 4 and the structural formula (2) of R ═ CH₂CH₂COOC₁₂H₂₅The mixture of 2, 3-glycidoxypropyl 1, 3-bis (2, 3-glycidoxypropyl) -5, 7-bis (propionyloxylauryl ester) -1,3,5, 7-tetramethylcyclotetrasiloxane and 1, 5-bis (2, 3-glycidoxypropyl) -3, 7-bis (propionyloxylauryl ester) -1,3,5, 7-tetramethylcyclotetrasiloxane having the structure shown in formula (3) is stirred and mixed evenly to obtain 100.00g of total organosilicon modified epoxy resin, then 10.0g of neopentyl glycol diglycidyl ether reactive diluent, 0.75g of BYK-161 dispersant and 30.0g of Al are added₂O₃Stirring and uniformly mixing, stirring and dispersing for 45min by using a high-speed dispersion machine with the rotating speed of 1000r/min, and then stirring and dispersing for P_{Watch (A)}Vacuumizing and defoaming for 15min under the condition of 0.7MPa, and recording the obtained mixture as A4 component.

Then, based on the number of moles of epoxy groups contained in the component of system a 4: in the component B4, the mole number of (anhydride group + carboxyl group) in the anhydride curing agent is about 1:0.9, a curing agent B4 (which is preheated and dissolved into a transparent state) consisting of 74.94g of methylhexahydrophthalic anhydride and 5.40g of pyromellitic dianhydride and 0.92g of 2-ethyl-4-methylimidazole curing accelerator are weighed, A4, B4 and the curing accelerator are stirred and mixed uniformly, and the obtained mixture is the anhydride curable organosilicon modified epoxy potting adhesive, which is marked as ASE-4.

Example 5 (comparative example to example 1)

The formulation and amounts of the raw materials were the same as in example 1 except that 1,3,5, 7-tetrakis (2, 3-glycidoxypropyl) tetramethylcyclotetrasiloxane, 1, 3-bis (2, 3-glycidoxypropyl) -5, 7-dioctyl-1, 3,5, 7-tetramethylcyclotetrasiloxane and 1, 5-bis (2, 3-glycidoxypropyl) -3, 7-dioctyl-1, 3,5, 7-tetramethylcyclotetrasiloxane were not added, and component A5 was prepared in the same manner.

Then, based on the number of moles of epoxy groups contained in the a5 component: the mole number of (anhydride group + carboxyl group) in the anhydride curing agent of the component B5 is about 1:1, methyl hexahydrophthalic anhydride curing agent (B5) is weighed, and then the components A5 and B5 are stirred and mixed uniformly, and the obtained mixture is the anhydride curable epoxy potting adhesive and is used as the reference of the embodiment 1.

Example 6 (comparative example to example 2)

The formulation and the raw material amount are the same as those of example 2, but 1,3,5, 7-tetra (2, 3-glycidoxypropyl) tetramethylcyclotetrasiloxane, 1, 3-di (2, 3-glycidoxypropyl) -5, 7-dioctyl-1, 3,5, 7-tetramethylcyclotetrasiloxane and 1, 5-di (2, 3-glycidoxypropyl) -3, 7-dioctyl-1, 3,5, 7-tetramethylcyclotetrasiloxane in example 2 are equivalently replaced by commercially available terminal epoxy silicone oil (Zhejiang Henhancao chemical Co., Ltd.) having a viscosity of about 190mPa.s and an epoxy group content of about 0.02%, or by side chain epoxy silicone oil (Zhejiang Henhang Hengham Co., Ltd.) having a viscosity of about 130mPa.s and an epoxy group content of about 0.2%, and silicone modified by the same method as that the component A6 of silicone potting adhesive is prepared, after being stirred uniformly, the system is turbid and opaque and is divided into an upper layer and a lower layer after being placed.

Mixing A6 and B2 curing agent according to the mole number of epoxy groups contained in A6: component B2 anhydride curing agent (anhydride group + carboxyl group) mole number about 1: 0.8A 6 and B2 were mixed and stirred uniformly under the same curing conditions as in example 2, and as a result: the surface of the pouring sealant layer is sticky and cannot be effectively cured.

Performance testing

Pouring the organic silicon modified epoxy pouring sealant prepared in the examples 1 to 5 and a comparison sample into a polytetrafluoroethylene mold for testing to prepare a test sample with the thickness of about 2 mm; or the clean tinplate after roughening treatment is used as a base material, the organic silicon modified epoxy pouring sealant and the comparison sample prepared in the embodiment 1-5 are taken, and the pouring sealant is coated on the surface of the tinplate by a 80-mesh wire rod to prepare a test sample with the thickness of 25-30 mu m; leveling all test samples at room temperature for 30min, then placing the test samples in an oven to be cured for 60min at the temperature of 120-150 ℃, balancing the obtained samples, namely the anhydride-cured organosilicon modified epoxy resin pouring sealant test samples for 24h at the conditions of the room temperature of 25 +/-2 ℃ and the relative humidity RH of about 48 percent, and then carrying out related performance determination: shore A hardness is determined by a TIME5430 digital Shore A durometer according to GB/T531-1999; the elongation at break is determined by referring to a universal tensile machine for preparing samples of GB/T1040.1-2006; the impact resistance of the adhesive layer is determined with an impact resistance tester according to GB/T1732-1993; the flexibility of the adhesive layer is measured by an QTX type paint film flexibility measuring instrument according to a paint film testing method; the aging resistance is determined by a KK-SN-150 xenon lamp aging resistance test box according to GB/T2423.24-1995 standard; the waterproof performance of the surface of the adhesive layer of the epoxy pouring sealant is represented by a contact angle (WCA) of water on the surface of the adhesive layer, and the size of a water drop is 5 mu L by using a JC-2000C1 type static contact angle measuring instrument; the larger the WCA is, the better the water repellency of the surface of the adhesive layer is and the better the moisture resistance is. Examples 1-5 the results of the experimental tests are shown in table 2.

Table 2 examples 1-5 test results of the performance of anhydride-cured silicone-modified epoxy resin potting adhesive

As can be seen from Table 2, compared with comparative example 5, the epoxy resin pouring sealant modified by epoxy group oligosiloxane of examples 1-4 has the advantages that the Shore hardness A of the sealant layer is reduced, the elongation at break is increased, the flexibility of the sealant layer (bent by a mandrel rod for 180 ℃) is reduced to 1mm from 2cm of the comparative example, the impact resistance is increased to be more than or equal to 70cm from 35cm of the comparative example, and the contact angle WCA of water on the surface of the sealant layer is increased to 89-112 ℃ from 73.6 degrees of the comparative example, which shows that the flexibility and the impact resistance of the sealant layer are increased and the surface hydrophobic moisture resistance is enhanced by the epoxy resin pouring sealant modified by organosilicon; in addition, the modified glue layer is irradiated for 1000 hours by a xenon lamp under the damp-heat conditions of 85 ℃ and 85% of relative humidity RH, and the surface of the glue layer is light yellow and has no obvious change, which shows that the epoxy resin pouring sealant modified by organic silicon has the effects of reducing the hardness of the epoxy pouring sealant, improving the impact resistance and the flexibility of the glue layer and improving the surface hydrophobic and moisture-proof effects of the glue layer.