CN112812721B

CN112812721B - Curable epoxy resin composition

Info

Publication number: CN112812721B
Application number: CN202110180553.XA
Authority: CN
Inventors: 宋志勇; 刘栋梁; 张小燕
Original assignee: Sika Technology AG
Current assignee: Sika Technology AG
Priority date: 2021-02-08
Filing date: 2021-02-08
Publication date: 2022-12-06
Anticipated expiration: 2041-02-08
Also published as: WO2022166825A1; CN112812721A

Abstract

The present invention relates to a curable epoxy resin composition comprising a) an epoxy resin; b) A curing agent comprising a polyamide PA and a polyoxyethylene-based polyetheramine PEA, and the weight ratio of the polyamide PA to the polyetheramine PEA is in the range of 1.3 to 5; and C) a filler comprising alumina and silica. The invention also relates to adhesives, sealants or potting compounds which contain the epoxy resin compositions and are used in particular in electronic products and components thereof.

Description

Curable epoxy resin composition

Technical Field

The present invention relates to the field of curable epoxy resin compositions. Furthermore, the use of the epoxy resin compositions as adhesives, sealants or potting compounds, in particular for electronic products and components thereof, is also disclosed.

Background

Epoxy resins are used in a variety of applications, for example as adhesives, coatings, sealants or molding compositions for the production of molded articles. Inorganic fillers are often added to epoxy resins during processing to affect the properties of the curable resin or the cured plastic material. The inorganic filler improves, for example, the strength of the epoxy resin or the adhesion of the resin to the substrate. Inorganic fillers in epoxy resins also fulfill many other functions such as flame retardants, insulators, viscosity modifiers or dyes (as pigments). Another object is to save expensive epoxy resin and thus cost.

In addition, the epoxy resin also needs to react with a curing agent to form a network-like crosslinked polymer to obtain a cured epoxy resin. Curing agents commonly used for epoxy resins include a wide variety of species, such as polyamines, e.g., aliphatic polyamines and aromatic polyamines, and other nitrogen-containing compounds and polyamides, and the like, as well as organic acid or anhydride based curing agents, and guanidine or amidine compounds, and the like. The type and amount of the curing agent are generally dependent on the mechanical properties of the epoxy resin after final curing, such as impact resistance and brittleness, and weather resistance, etc.

CN106281174A discloses a high-toughness, impact-resistant, and high-flexibility epoxy potting adhesive, which especially comprises a toughening epoxy resin, a bisphenol a type epoxy resin, aluminum oxide, and a special curing agent component. The curing agent component comprises a compound of hyperbranched polyethyleneimine and isophorone diamine and a polyether amine curing agent.

CN106318298A discloses a curing agent component system for preparing a normal temperature curing anti-cracking epoxy potting adhesive, wherein the curing agent component is based on modified aromatic amine, aliphatic amine and imidazole compound.

CN109401708A discloses a normal temperature curing pouring sealant, which comprises epoxy resin, a normal temperature curing agent and a heat conductive filler, wherein the heat conductive filler is composed of silicon nitride or boron nitride and aluminum oxide.

CN106634752A discloses an epoxy resin potting adhesive special for an ignition coil, which comprises two components A and B, wherein the component A comprises bisphenol A epoxy resin, PEO-PPO-PEO triblock copolymer, carboxyl-terminated liquid nitrile butadiene rubber, silica fume, aluminum hydroxide and the like. Here, the microsilica generally functions as a thixotropic agent or rheology modifier and has a particle size of less than 1 micron.

However, there is no specific attention in these prior arts on the possibility of further improving the aging resistance and mechanical properties of the epoxy resin composition by compounding a specific curing agent with a filler.

Summary of The Invention

The object of the present invention is to provide an epoxy resin composition which can be cured, in particular, at moderate or room temperature (i.e., in the temperature range of about 10 to 80 ℃), and which is used as a potting material. The epoxy resin composition should have good mechanical properties while also having low viscosity, excellent cold/thermal shock resistance, low volatility and good adhesion.

In particular, the epoxy resin compositions according to the present invention have beneficial crack resistance properties after aging through high and low temperature cycles (e.g., -40 ℃ to 80 ℃) and high temperature and high humidity cycles (e.g., 80 ℃/95% relative humidity). In addition, the compositions according to the invention have very good adhesion on many substrates, for example Al — Mg alloy substrates, cu and polycarbonate substrates.

The inventors have surprisingly found that the epoxy resin composition according to claim 1 achieves the above-mentioned object by comprising two specific curing agents and two specific filler combinations.

Other aspects of the invention are the subject of other independent claims. Particularly preferred embodiments of the invention are the subject matter of the dependent claims.

Detailed Description

A first aspect of the present invention relates to a curable two-component epoxy resin composition comprising

A) An epoxy resin;

b) A curing agent comprising a polyamide PA and a polyoxyethylene-based polyetheramine PEA, and the weight ratio of polyamide PA to polyetheramine PEA is in the range of 1.3-5; and

c) A filler comprising alumina and silica.

The names of compounds starting with "poly" refer to materials that formally contain two or more of the functional groups present in their names per molecule. The compound may be a monomer, oligomer or polymer. For example, a polyamine is a compound having two or more amine groups. Polyepoxides are compounds having two or more epoxy groups.

Amine compounds having two or more amino groups per molecule are hereinafter referred to as "polyamines". If the polyamines are polymers, they contain on average at least two amine groups per molecule.

Average molecular weight, if not otherwise stated, is understood to mean the number average molecular weight determined using conventional methods, preferably generally using Gel Permeation Chromatography (GPC) at 35 ℃, where polystyrene is generally used as standard, styrene-divinylbenzene with porosities of 100 angstroms, 1000 angstroms and 10000 angstroms is used as column and tetrahydrofuran is used as solvent.

The epoxy resin composition includes a crosslinkable epoxy resin having an average of more than one epoxy group per molecule. They react with suitable curing agents to form chemical bonds. The epoxy resin is preferably an oligomeric or polymeric compound. Epoxy resins are sometimes also used with so-called reactive diluents. The reactive diluent is a mono-or polyepoxide. The reactive diluent has a lower viscosity than the epoxy resin used and serves to reduce the viscosity of the epoxy resin used. The optional reactive diluent is likewise incorporated into the organic binder matrix and is therefore incorporated into the epoxy resin here when determining the organic binder content.

The Epoxy Equivalent Weight (EEW) can be determined according to DIN 53188 and is reported in g/Eq. The NH equivalent can be determined according to DIN16945 and reported as g/Eq. The stoichiometric ratio of epoxy functional groups to amine functional groups is the quotient of epoxy equivalents to active hydrogen in the amine, i.e., NH (amine hydrogen) equivalents, and is often reported in%. The NH equivalent is herein based on active hydrogen, i.e. amine hydrogen. Primary amines, for example, have two active amine hydrogens.

The composition of the present invention is a two-component composition, i.e. the composition comprises two individual components which are only mixed with each other at the time of use. The components are separately stored in two separate containers (e.g., cartridges, barrels, bags, pouches, bins, cartridges, etc.) prior to use to avoid spontaneous reactions. For use, the components are mixed with each other. After mixing, an organic crosslinking reaction can optionally be initiated, which ultimately results in curing of the mixture.

It will be apparent that the proportion of a particular ingredient in a mixture of said components will depend on the proportion of such ingredient in the component concerned and the mixing ratio of said components. The proportions or ratios of particular ingredients specified herein relate to reasonable or suitable weight proportions or weight ratios of the ingredients in the component mixtures of the multicomponent composition, unless otherwise specified. This is achieved, for example, by mixing the components in a suitable mixing ratio according to the instructions for use.

As the epoxy resin of component a), one epoxy resin or a mixture of two or more epoxy resins may be used. As epoxy resins, all epoxy resins customary in epoxy chemistry can be used. The epoxy resins can be prepared, for example, in a known manner by oxidation of the corresponding olefins or by reaction of epichlorohydrin with the corresponding polyols or polyphenols.

Epoxy resins can be subdivided into liquid epoxy resins and solid epoxy resins. The epoxy resin may, for example, have an epoxy equivalent weight of from 156 to 500 g/Eq. The epoxy resin is preferably a diepoxide.

In one embodiment, the epoxy resin may be an aromatic epoxy resin. A suitable example for this purpose is a liquid epoxy resin of formula (III):

wherein R 'and R' are each independently a hydrogen atom or a methyl group, and s is an average value of 0 to less than 2 and preferably 0 to 1. Preferred are those liquid resins of formula (III) wherein the index s is an average value of less than 0.2.

The epoxy resins of formula (III) are diglycidyl ethers of bisphenol A, bisphenol F and bisphenol A/F, in which A represents acetone and F represents formaldehyde, which are used as reactants for the preparation of these bisphenols. Such liquid epoxy resins are commercially available, for example under the following names: from Huntsman

From Dow

From Momentive

From CVC

Chem from Cognis

Or from Cytec

Further suitable aromatic epoxy resins are the glycidylation products of:

dihydroxybenzene derivatives such as resorcinol, hydroquinone and pyrocatechol;

other bisphenols or polyphenols such as bis (4-hydroxy-3-methylphenyl) methane, 2-bis (4-hydroxy-3-methylphenyl) propane (bisphenol C), bis (3, 5-dimethyl-4-hydroxyphenyl) methane, 2-bis (3, 5-dimethyl-4-hydroxyphenyl) propane, 2, 2-bis (3, 5-dibromo-4-hydroxyphenyl) propane, 2-bis (4-hydroxy-3-tert-butylphenyl) propane, 2-bis (4-hydroxyphenyl) butane (bisphenol B), 3-bis (4-hydroxyphenyl) pentane, 3, 4-bis (4-hydroxyphenyl) hexane, 4-bis (4-hydroxyphenyl) heptane, 2, 4-bis (4-hydroxyphenyl) -2-methylbutane, 2, 4-bis (3, 5-dimethyl-4-hydroxyphenyl) -2-methylbutane, 1-bis (4-hydroxyphenyl) cyclohexane (bisphenol Z), 1-bis (4-hydroxyphenyl) -3, 5-trimethylcyclohexane (bisphenol TMC), 1-bis (4-hydroxyphenyl) -1-phenylethane, 1, 4-bis [2- (4-hydroxyphenyl) -2-propyl ] benzene (bisphenol P), 1, 3-bis [2- (4-hydroxyphenyl) -2-propyl ] benzene (bisphenol M), 4 '-dihydroxybiphenyl (DOD), 4' -dihydroxybenzophenone, bis (2-hydroxynaphthalen-1-yl) methane, bis (4-hydroxynaphthalen-1-yl) methane, 1, 5-dihydroxynaphthalene, tris (4-hydroxyphenyl) methane, 1, 2-tetrakis (4-hydroxyphenyl) ethane, bis (4-hydroxyphenyl) ether, bis (4-hydroxyphenyl) sulfone;

condensation products of phenols obtained under acidic conditions with formaldehyde, such as novolak resins or cresol novolak resins;

aromatic amines such as aniline, toluidine, 4-aminophenol, 4 '-Methylenediphenyldiamine (MDA), 4' -methylenediphenyldi (N-methyl) amine, 4'- [1, 4-phenylenebis (1-methylethylidene) ] dianiline (dianiline-P), 4' - [1, 3-phenylenebis (1-methylethylidene) ] dianiline (dianiline M).

In another embodiment, the epoxy resin may be an aliphatic or cycloaliphatic epoxy resin, for example

-a diglycidyl ether;

glycidyl ethers of saturated or unsaturated, branched or unbranched cyclic or open-chain C2-C30 diols, such as ethylene glycol, propylene glycol, butanediol, hexanediol, octanediol, polypropylene glycol, dimethylolcyclohexane, neopentyl glycol;

-glycidyl ethers of tri-or tetrafunctional saturated or unsaturated branched or unbranched cyclic or open-chain polyols, such as castor oil, trimethylolpropane, trimethylolethane, pentaerythritol, sorbitol or glycerol, and also alkoxylated glycerol or alkoxylated trimethylolpropane;

-a hydrogenated liquid bisphenol a, F or a/F resin, or a glycidylation product of a hydrogenated bisphenol a, F or a/F;

n-glycidyl derivatives of amides or heterocyclic nitrogen-containing bases, such as triglycidyl cyanurate and triglycidyl isocyanurate, and reaction products of epichlorohydrin and hydantoin.

Further examples of useful epoxy resins are those prepared by oxidation of olefins, for example vinylcyclohexene, dicyclopentadiene, cyclohexadiene, cyclododecadiene, cyclododecatriene, isoprene, hexa-1, 5-diene, butadiene, polybutadiene or divinylbenzene.

Further examples of epoxy resins which can be used are solid bisphenol A, F or A/F resins, which are built up in the same way as the aforementioned liquid epoxy resins of the formula (III), except that the value of the index s is from 2 to 12. Further examples are all the aforementioned epoxy resins which have been hydrophilically modified by reaction with at least one polyoxyalkylene polyol.

Preferred epoxy resins are bisphenol A, F or A/F solid or liquid resins such as those commercially available from Dow, huntsman, momentive, HEXION or Taiwan south Asia of China and such as those commercially available from Changchun chemical industries (Jiangsu) Ltd or Macro Chang electronics. The epoxy resins used are particularly preferably bisphenol A diglycidyl ether, bisphenol F diglycidyl ether and the diepoxides of bisphenol A/F diglycidyl ether, in particular those having an epoxy equivalent of 156 to 25 g/Eq, for example those commercially available

GY250，

PY304，

GY282 (commercially available from Huntsman);

331，

330 (commercially available from Dow);

828，

862 (commercially available from Momentive), and N, N-diglycidylaniline and polyethylene glycol diglycidyl ether, preferably with an epoxy equivalent weight of from 17 to 340g/Eq, for example as commercially available products

732 and

736 (commercially available from Dow).

It may be advantageous to also include at least one reactive diluent for the epoxy resin in the epoxy resin composition. As stated, it is taken into account for the organic binder content in the epoxy resin. One or more reactive diluents may be used. Suitable reactive diluents are mono-and polyepoxides. The addition of reactive diluents to epoxy resins results in a decrease in viscosity.

Examples of reactive diluents are glycidyl ethers of mono-or polyhydric phenols and aliphatic or cycloaliphatic alcohols, such as, in particular, the polyglycidyl ethers of dihydric or polyhydric alcohols which have been mentioned as aliphatic or cycloaliphatic epoxy resins, such as butanediol diglycidyl ether, and also, in particular, phenyl glycidyl ether, cresyl glycidyl ether, p-n-butylphenyl glycidyl ether, p-tert-butylphenyl glycidyl ether, nonylphenyl glycidyl ether, allyl glycidyl ether, butyl glycidyl ether, hexyl glycidyl ether, 2-ethylhexyl glycidyl ether, and glycidyl ethers of natural alcohols, such as C8-to C10-alkyl glycidyl ethers, C12-to C14-alkyl glycidyl ethers or C13-to C15-alkyl glycidyl ethers, as

GE-7，

GE-8 (from CVC) or as

P13-19 (from Leuna) is commercially available.

Preferably, the epoxy resin is present in an amount of from 2.5 to 30wt%, more preferably from 5 to 25wt%, especially for example from 10 to 25wt%, based on the weight of the total composition.

The curable epoxy resin composition according to the present invention further comprises a curing agent, the choice of which is critical in the present invention. The curing agent component according to the invention comprises a combination of polyamide PA and polyoxyethylene-based polyetheramine PEA. Preferably, the curing agent consists of polyamide PA and polyoxyethylene-based polyetheramine PEA.

According to the invention, the curing agent for epoxy resins, polyamide PA, is a polyamidopolyamine which is the reaction product of a mono-or polycarboxylic acid or an ester or anhydride thereof, in particular a reaction product of a dimer fatty acid with a stoichiometric excess of an aliphatic, cycloaliphatic or aromatic polyamine, in particular a polyalkyleneamine such as DETA or triethylenetetramine (TETA), in particular a commercially available polyamide-based polyamine

100. 125, 140 and 150 (from Cognis),

125. 140, 223, 250, and 848 (from Huntsman),

3607、

530 (from Huntsman),

EH 651, EH 654, EH 655, EH 661, and EH 663 (from Cytec).

In a preferred embodiment, the polyamide PA has an active H equivalent of 125 to 300, preferably 180 to 250 g/Eq. This is advantageous for further improving the weather resistance. It is also advantageous for the molecular weight of the polyamide PA to be in the range from 500 to 1200g/mol, preferably from 650 to 1000 g/mol.

Another curing agent for epoxy resins, polyetheramine PEA, has a structure based on a polyether or polyoxyalkylene backbone, also known as polyetherpolyamine or polyoxyalkylene polyamine, having more than one, preferably two or three or more amine groups, wherein the polyether or polyoxyalkylene backbone is ethylene oxide based.

In the context of the present application, the expression "polyoxyethylene-based" polyetheramine PEA means in particular that the polyether chain or polyoxyalkylene chain in the polyetheramine comprises at least 80% by weight, preferably at least 90% by weight, more preferably 95% or 100% by weight, of oxyethylene (EO) units, based on the total weight of all oxyalkylene units, i.e. the entire polyether chain or polyoxyalkylene chain. In addition to the oxyethylene units, the polyetheramine PEA according to the invention may also contain small amounts of other oxyalkylene units, such as oxypropylene or oxybutylene units. An excessively low oxyethylene unit content is disadvantageous in particular with regard to weathering resistance, such as resistance to cracking.

Furthermore, it is advantageous if the molecular weight of the polyetheramine PEA is in the range from 140 to 350g/mol, preferably from 160 to 300 g/mol.

Examples of such polyetheramine PEAs include, for example, 4,7,10-trioxatridecane-1-13-diamine and polyetheramines based on polyoxyethylene diamines, such as those commercially available, which are usually products from the amination of polyoxyethylene glycols, such as

EDR-148 and

EDR-176 and the like.

The polyetheramine PEA is more preferably a polyoxyethylene diamine or triamine, and particularly preferably a polyoxyethylene diamine, from the viewpoint of curing rate, mechanical properties and in view of compounding with the polyamide PA.

According to the invention, the curing agent is present in an amount of 5 to 30 wt.%, preferably 7.5 to 20 wt.%, based on the weight of the entire composition. More preferably, the curing agent comprises at least 90wt%, preferably at least 95wt%, more preferably at least 98wt% and especially preferably at least 99wt% of the combination of the polyamide PA and polyetheramine PEA. It is particularly preferred that the curing agent consists entirely of the polyamide PA and polyetheramine PEA, i.e. no further curing agent is used in this case.

In the present invention, the weight ratio of the polyamide PA to the polyetheramine PEA in the curing agent component is in the range of 1.3 to 5, preferably 1.5 to 4.5. If the ratio of the two is less than 1.3; whereas if the ratio of the two is too high, e.g. above 5, 1, it may result in the curing agent component being unduly high in viscosity and causing the cured product to emit more volatiles at elevated temperatures or heat, while also being detrimental to mechanical properties and curing.

As noted above, minor amounts of other amine-containing curing agents can be included in the curing agent component of the present invention in addition to the polyamide PA and polyether amine PEA.

Other polyamines suitable as curing agents are, for example:

aliphatic or araliphatic primary diamines, such as ethylenediamine, 1, 2-propylenediamine, 1, 3-propylenediamine, 2-methyl-1, 2-propylenediamine, 2-dimethyl-1, 3-propylenediamine, 1, 3-butylenediamine, 1, 4-butylenediamine, 1, 3-pentylenediamine (DAMP), 1, 5-pentylenediamine, 1, 5-diamino-2-methylpentane (MPMD), 2-butyl-2-ethyl-1, 5-pentylenediamine (C11-neopentyldiamine), 1, 6-hexylenediamine, 2, 5-dimethyl-1, 6-hexyldiamine, 2, 4-and 2, 4-Trimethylhexamethylenediamine (TMD), 1, 7-heptanediamine, 1, 8-octanediamine, 1, 9-nonanediamine, 1, 10-decanediamine, 1, 11-undecanediamine, 1, 12-dodecanediamine, 1, 8-menthanediamine, 3, 9-bis- (3-aminopropyl) -2, 8-tetraoxa-tetraxylenediamine and 1,3, 5-xylylenediamine;

secondary amino-containing polyamines, such as Diethylenetriamine (DETA), N-bis- (2-aminoethyl) -ethylenediamine, dipropylenetriamine (DPTA), bis-hexamethylenetriamine (BHMT), 3- (2-aminoethyl) -aminopropylamine, triethylenetetramine, tetraethylenepentamine, N3- (3-aminopentyl) -1, 3-pentanediamine, N5- (3-aminopropyl) -2-methyl-1, 5-pentanediamine, N5- (3-amino-1-ethylpropyl) -2-methyl-1, 5-pentanediamine, N' -dibutylethylenediamine; n, N ' -di-tert-butylethylenediamine, N ' -diethyl-1, 6-hexanediamine, 1- (1-methylethylamino) -3- (1-methylethyl-aminomethyl) -3, 5-trimethylcyclohexane (N, N ' -di-tert-butylethylenediamine, N ' -diethyl-1, 6-hexanediamine, N ' -trimethylcyclohexane

754 from Huntsman), N4-cyclohexyl-2-methyl-N2- (2-methylpropyl) -2, 4-pentanediamine, N '-dialkyl-1, 3-xylylenediamine, bis- (4- (N-alkylamino) -cyclohexyl) -methane, 4' -trimethylenedipiperidine, N-alkylated polyetheramines, for example,

types SD-231, SD-401, SD-404 and SD-2001 (from Huntsman);

-amine/polyepoxide adducts; in particular adducts of the above mentioned polyamines with diepoxides in a molar ratio of at least 2/1, in particular in a molar ratio of from 2/1 to 10/1;

polyethyleneimine (PEI), which is a branched polymeric amine from the polymerization of ethyleneimine. Suitable polyethyleneimines generally have an average molecular weight of from 250 to 25000g/mol and contain tertiary, secondary and primary amino groups. Polyethyleneimine is available, for example, under the trade name

(from BASF), e.g.

WF、

FG、

G20 and

PR 8515.

-a mannich base; i.e. amines with other functional groups, which can be obtained by a mannich reaction, in which aminoalkylation of CH-acidic compounds with aldehydes and ammonia, or primary or secondary amines, takes place.

However, from the viewpoint of the compromise between curing efficiency and health risk of the user, in a preferred embodiment of the epoxy resin composition of the present invention, it is advantageous that the curing agent does not contain aliphatic or aromatic polyamines such as primary diamines, triamines and tetramines.

Furthermore, the epoxy resin composition according to the invention must also comprise fillers, preferably inorganic fillers. The inorganic filler is preferably a mineral filler. The inorganic filler may be of natural origin or artificially produced. Suitable fillers are known in the art and are commercially available. The filler may be a synthetic filler or a naturally occurring mineral. They are preferably oxygen-containing compounds. Typically, oxides, mixed oxides or metals and semimetals are used. As fillers, powders as well as hollow spheres (e.g. made of glass or ceramic) or in the form of fibers can be used.

The inventors of the present invention have found that, in the epoxy resin composition of the present invention, if alumina and silica are contained in the filler, excellent cracking resistance can be provided, particularly after aging at high and low temperatures and high humidity.

Preferably, the filler is present in an amount of 20 to 80wt%, preferably 25 to 75wt%, more preferably 35 to 70wt%, based on the weight of the total composition. Preferably, in order to guarantee excellent cracking resistance, the sum of both the alumina and the silica represents at least 50% by weight, preferably at least 60% by weight, more preferably at least 70% by weight and especially preferably at least 90% by weight or 100% by weight of the total weight of the filler.

The alumina used in the filler of the present invention is a stable oxide of aluminum commonly used in industry and having a chemical formula of Al ₂ O ₃ Also known as alumina. Alumina fillers are commercially available, for example, from Guangdong-Lot and Zibonoda chemical industries, among others.

Within the scope of the present invention, the silica is a filler which may be, for example, in the form of quartz, for example quartz powder or quartz sand, and generally has a particle size of more than 1 μm, preferably more than 1.5 μm, and is therefore distinguished from so-called microsilica, such as fumed silica and the like. The latter typically 80% or more of the powder has a particle size of less than 1 μm, with an average particle size of between 0.1 and 0.5 or 0.1 and 0.3 μm, and is commonly used as a rheology modifier. Silica fillers are also commercially available, for example, from Guangdong Toxico and Shanghai Baitu.

Preferably, the silica and/or alumina suitable for the present invention is a particulate powder having a particle size (D50) in the range of 2 to 20 μm, preferably 3 to 15 μm, such as 4 to 10 μm. In the context of the present invention, the particle size or average particle size refers to the D50 value, which can be measured by laser diffraction, preferably using a Mastersizer 2000 apparatus (trade mark of Malvern Instruments Ltd, GB).

Preferably in the present invention, the alumina: the weight ratio of silica is in the range of 4. If the ratio of the two is too low, e.g., less than 4; and if the ratio of the two is too high, such as more than 8.

It has been found in accordance with the present invention that simple non-surface treated inorganic fillers can be incorporated into epoxy resin compositions. Although not required, in a preferred embodiment of the invention, the filler, particularly the alumina and silica particles, may be surface treated, for example with a silane coupling agent. Such surface treatments are known.

Fillers which may be added include, for example, metal oxides such as titanium oxide, iron oxide, zinc oxide and magnesium oxide; metal carbonates such as calcium carbonate or dolomite; metal sulfates such as calcium sulfate (gypsum) and barium sulfate; metal hydroxides such as aluminum hydroxide, aluminum nitride or aluminum carbide, clay minerals such as kaolin, fly ash, cement, glass and ceramic materials.

The epoxy resin compositions according to the invention may also contain other conventional additives. Various additives are well known in the art of epoxy resins, which affect the properties of the curable composition or cured epoxy resin. The proportion of additives contained in the epoxy resin composition in addition to the epoxy resin, curing agent, filler may (including solvents) be, for example, up to 50wt%, up to 20wt%, up to 5wt% or up to 2wt%. In a preferred embodiment of the invention, the at least one further additive is selected from the group consisting of reactive diluents, film-forming agents, fillers, catalysts, accelerators, rheology modifiers, adhesion promoters, stabilizers, defoamers, deaerators, flame retardants, surfactants, biocides, organic dyes and pigments, and further dispersing agents. These include, for example:

-an organic dye;

accelerators which accelerate the reaction between amino and epoxy groups, for example acids or compounds which can be hydrolyzed to form acids, for example organic carboxylic acids such as acetic acid, benzoic acid, salicylic acid, 2-nitrobenzoic acid, lactic acid, organic sulfonic acids such as methanesulfonic acid, p-toluenesulfonic acid or 4-dodecylbenzenesulfonic acid, sulfonic esters, other organic or inorganic acids such as phosphoric acid, or mixtures of the abovementioned acids and acid esters; furthermore, tertiary amines such as 1, 4-diazabicyclo [2.2.2] octane, benzyldimethylamine, α -methylbenzyldimethylamine, triethanolamine, dimethylaminopropylamine, salts of these tertiary amines, quaternary ammonium salts, for example benzyltrimethylammonium chloride, phenols, in particular bisphenols, phenolic resins and mannich bases such as 2- (dimethylaminomethyl) -phenol and 2,4, 6-tris- (dimethylaminomethyl) -phenol, phosphites, for example diphenyl phosphite and triphenyl phosphite, and also those mercapto-containing compounds which have already been mentioned above; a catalyst;

rheology modifiers, such as in particular thickeners, for example phyllosilicates, such as bentonites, castor oil derivatives, hydrogenated castor oil, polyurethanes, urea compounds, fumed silica, cellulose ethers and hydrophobically modified polyoxyethylenes;

adhesion promoters, for example organoalkoxysilanes such as 3-glycidoxypropyltrimethoxysilane, 3-aminopropyl-trimethoxysilane, N- (2-aminoethyl) -N' - [3- (trimethoxysilyl) -propyl ] -ethylenediamine, 3-ureidopropyltrimethoxysilane, 3-chloropropyltrimethoxysilane, vinyltrimethoxysilane or corresponding organosilanes having ethoxy or (poly) etheroxy groups instead of methoxy groups;

-stabilizers against oxidation, heat, light and ultraviolet radiation;

flame retardants, in particular compounds such as aluminum hydroxide (Al (OH) ₃ (ii) a Also known as ATH for "aluminum trihydrate"), magnesium hydroxide (Mg (OH) ₂ (ii) a Also known as MDH for "magnesium dihydrate"), ammonium sulfate ((NH) ₂ SO ₄₎ Boric acid (B (OH) ₃₎ Zinc borate, melamine borate and melamine cyanurate; phosphorus-containing compounds, e.g. ammonium phosphate ((NH) ₄ ) ₃ PO ₄ ) Ammonium polyphosphate, melamine phosphate, melamine pyrophosphate, triphenyl phosphate, diphenylcresyl phosphate, tricresyl phosphate, triethyl phosphate, tris (2-ethylhexyl) phosphate, trioctyl phosphate, mono-, bis-and tris- (isopropylphenyl) phosphates, resorcinol-bis- (diphenyl phosphate), resorcinol diphosphate oligomers, tetraphenyl-resorcinol diphosphate, ethylenediamine diphosphate, and bisphenol a-bis- (diphenyl phosphate)); halogen-containing compounds, e.g. chloroalkyl phosphates, in particular tris- (chloroethyl) phosphate, tris- (chloropropyl) phosphate and tris- (dichloroisopropyl) phosphate, polybromodiphenyl ethers, in particular decabromodiphenyl ether, polybromodiphenyl oxide, tris [ 3-bromo-2, 2-bis- (bromomethyl) -propyl ] phosphate]Phosphoric acid ester, tetrabromobisphenol A, bis- (2, 3-dibromopropyl ether) of bisphenol A, brominated epoxy resin, ethylene-bis- (tetrabromophthalimide), ethylene-bis- (dibromonorbornane-dicarboximide), 1, 2-bis- (tribromophenoxy) ethane, tris- (2, 3-dibromopropylidene)Yl) isocyanurate, tribromophenol, hexabromocyclododecane, bis- (hexachlorocyclopentadienyl) cyclooctane and chlorinated paraffin;

surfactants, such as wetting agents, levelling agents, degassing agents or defoamers;

biocides, such as algicides, bactericides or fungal growth inhibitors.

The epoxy resin composition according to the present invention may be provided as a two-component system. Thus, the composition comprises two separate components. The components are stored separately, in particular to avoid spontaneous reactions. However, the components may be assembled together as a single package. In use, the components are combined with each other. When the components are mixed together, a curing reaction is initiated such that the composition is processed within an open time after mixing the components.

Curable epoxy resin compositions are often provided to the consumer as two-component systems. In this case, for example, the epoxy resin and the curing agent are usually contained in different components, and thus the curing reaction may be performed only when the user mixes the components. The filler may be part of one or both of these components.

In a preferred embodiment, the epoxy resin composition according to the invention is two-component, wherein the first component comprises the epoxy resin and at least a part of the filler, and the second component comprises the curing agent and optionally a part of the filler, preferably a curing agent and a part of the filler. More preferably, the first component comprises 5 to 60wt%, preferably 10 to 50wt%, of said epoxy resin and 20 to 80wt%, preferably 25 to 75wt%, more preferably 35 to 70wt%, of said filler, based on 100 parts by weight of the total weight of the first component; and a second component comprising 10 to 60wt%, preferably 15 to 50wt%, of the curing agent and 20 to 80wt%, preferably 25 to 75wt%, more preferably 35 to 70wt%, of the filler, based on 100 parts by weight of the total weight of the second component.

It was very surprisingly found that when the epoxy resin composition of the present invention is formulated into a two-component system, the first component and the second component can be used in about equal weight ratios, i.e. in a weight ratio in the range of 0.85 to 1.15, preferably 0.9 to 1.1. This greatly facilitates formulation and application of the composition.

Yet another aspect of the invention relates to a method of bonding or sealing a substrate comprising:

a) Applying a composition as described above or a portion thereof to a first substrate;

b) Providing a second substrate having optionally applied thereto a composition or a portion thereof as described above;

c) Contacting the first and second substrates with each other and allowing the composition to cure;

wherein the first substrate and the second substrate are made of the same or different materials.

When the composition is formulated as a two-component composition, the two components may be mixed and stirred uniformly in the preferred weight ratio as described above, for example, 1. Before application to a substrate, the applied composition may be degassed as desired, for example, vacuum defoamed and then uniformly applied to a substrate. Subsequently, pressure may optionally be applied to the first and second substrates while they are in contact with each other. Curing of the composition may be carried out under conditions of heat and/or ambient temperature, for example at a temperature of from 50 to 70 ℃. Here, the preferable substrate may be selected from aluminum magnesium alloy, copper, stainless steel, polycarbonate, and the like.

Finally, the invention also relates to products, in particular electronic products and parts thereof, obtained after bonding, sealing or potting by means of adhesives, sealants or potting compounds comprising the epoxy resin compositions as described above.

Examples

Examples are described below, which explain the present invention in more detail. The invention is of course not limited to the described embodiments.

List of main raw materials

Test method

And (3) viscosity testing: the test was carried out at 23 ℃ and 50% relative humidity using a Brookfield viscometer with a number 6 spindle at 20rpm.

Tensile shear strength was measured according to ASTM D1002-10.

Hardness was measured according to ASTM D2240-86.

Surface smoothness: the cured product was visually observed for the appearance of wrinkles, projections, blisters, etc. If there are substantially no protrusions or bubbles are small and less than 3, it can be evaluated as flat; otherwise, the evaluation is uneven.

Weather resistance test the cold-heat shock aging test is described in detail below. The surface cracking was evaluated visually after treatment with different cycling conditions: if the surface does not have any cracks, the surface is evaluated as 'no crack'; if no more than 2 fine cracks are observed in the surface energy, the surface energy is evaluated as "few cracks"; if the surface had more than 2 cracks or large cracks, the evaluation was "cracking".

Procedure of experiment

The first component was prepared by pre-charging epoxy resin, diluent and other auxiliaries into the reactor in the amounts shown in table 1 below, and stirring at low speed for 10min. The mixed filler of silica and alumina was added in the amount shown in Table 1 and stirred at high speed for 40min. And finally, cleaning the residual materials on the wall of the reaction kettle and the stirring paddle, vacuumizing and stirring at a high speed for 20min, and discharging to serve as a first component.

The second component was prepared by pre-adding the polyamide PA, polyetheramine PEA and other additives in the amounts shown in Table 1 below to the reactor and stirring at low speed for 10min. The amount of the mixed filler of silica and alumina as shown in Table 1 was added thereto and stirred at high speed for 40min. And finally, cleaning the residual materials on the wall of the reaction kettle and the stirring paddle, vacuumizing and stirring at a high speed for 20min, and discharging to serve as a second component.

For tensile shear strength testing, the two prepared components were mixed in a weight ratio of 1:1, mixing and stirring for about 2min until all components of the adhesive are uniformly mixed, uniformly coating the mixture on two S5754AI sheets for bonding, wherein the curing pressure is contact pressure, the curing condition is 1 hour at 60 ℃, and standing at room temperature for 3 days. The results obtained are shown in Table 2.

For hardness testing, the two prepared components were mixed in a weight ratio of 1:1, mixing and stirring for about 2min until all components of the adhesive are uniformly mixed, defoaming in vacuum, and pouring into a hardness ring. The curing condition was 60 ℃ for 1 hour, and the mixture was left at room temperature for 3 days. The results obtained are shown in Table 2.

The weather resistance test was performed as follows: the prepared two components are mixed according to the weight ratio of 1:1, mixing and stirring for about 2min until all components are uniformly mixed, and pouring the mixture into a device to be tested after vacuum defoaming. The curing conditions were 60 ℃ for 1 hour, and then the mixture was left at room temperature for 3 days. The samples were then subjected to weathering tests under high and low temperature cycling and high temperature and high humidity cycling conditions as follows:

high and low temperature cycle conditions: keeping at-40 ℃ for 12h, then heating to 80 ℃ and keeping for 12h; cooling to-40 deg.C and maintaining for 2 hr, then increasing to 80 deg.C after 1.5 hr and maintaining for 2 hr; then after 1.5h it was cooled down to-40 ℃ and kept for 2h. The above cycle was performed once more.

High temperature and high humidity cycling conditions: held at 25 ℃/95% r.h for 9h; after 3h the temperature was raised to 80 ℃ and maintained for 9h and subsequently after 3h it was lowered to 25 ℃.

Table form

Claims

1. A curable epoxy resin composition comprising

A) An epoxy resin;

b) A curing agent comprising a polyamide PA and a polyoxyethylene-based polyetheramine PEA, and the weight ratio of the polyamide PA to the polyetheramine PEA is in the range of 1.3 to 5; and

c) A filler comprising alumina and silica.

2. Epoxy resin composition according to claim 1, characterized in that the weight ratio of polyamide PA to polyetheramine PEA is in the range of 1.5 to 4.5.

3. Epoxy resin composition according to claim 1, characterized in that the weight ratio of polyamide PA to polyetheramine PEA is in the range of 2-4.

4. Epoxy resin composition according to claim 1, characterized in that the epoxy resin composition is a two-component composition, wherein a first component comprises the epoxy resin and at least a part of the filler, and a second component comprises a curing agent and optionally a part of the filler.

5. The epoxy resin composition according to claim 4, characterized in that said second component comprises a curing agent and a portion of said filler.

6. Epoxy resin composition according to any of the preceding claims 1 to 5, characterized in that the polyamide PA has a reactive H equivalent of 125-300 g/Eq.

7. Epoxy resin composition according to any of the preceding claims 1 to 5, characterized in that the polyamide PA has a reactive H equivalent of 180-250 g/Eq.

8. Epoxy resin composition according to any one of the preceding claims 1 to 5, characterized in that the molecular weight of the polyetheramine PEA is in the range of 140-350 g/mol.

9. Epoxy resin composition according to any of the preceding claims 1 to 5, characterized in that the molecular weight of the polyetheramine PEA is in the range of 160-300 g/mol.

10. Epoxy resin composition according to any of the preceding claims 1 to 5, characterized in that the silica and/or alumina is a granulated powder with a particle size of 2-20 μm.

11. Epoxy resin composition according to any of the preceding claims 1 to 5, characterized in that the silica and/or alumina is a granulated powder with a particle size of 3-15 μm.

12. Epoxy resin composition according to any of the preceding claims 1 to 5, characterized in that the silica and/or alumina is a granulated powder with a particle size of 4-10 μm.

13. Epoxy resin composition according to any of the preceding claims 1 to 5, characterized in that the silica and/or alumina is surface treated.

14. The epoxy resin composition according to claim 13, characterized in that the silica and/or alumina is treated with a silane coupling agent.

15. The epoxy resin composition according to any of the preceding claims 1 to 5, characterized in that the alumina: the weight ratio of silica is in the range of 4.

16. The epoxy resin composition according to any of the preceding claims 1 to 5, characterized in that the alumina: the weight ratio of silica is in the range of 1.

17. The epoxy resin composition according to any of the preceding claims 1 to 5, characterized in that the alumina: the weight ratio of silica is in the range of 1.5.

18. Epoxy resin composition according to any one of the preceding claims 1 to 5, characterized in that the content of epoxy resin is 2.5 to 30 wt. -%, based on the weight of the total composition.

19. The epoxy resin composition according to any one of the preceding claims 1 to 5, characterized in that the content of epoxy resin is 5 to 25 wt.%, based on the weight of the entire composition.

20. The epoxy resin composition according to any one of the preceding claims 1 to 5, characterized in that the content of epoxy resin is 10-25 wt.%, based on the weight of the entire composition.

21. Epoxy resin composition according to any of the preceding claims 1 to 5, characterized in that the curing agent is present in an amount of 5 to 30 wt. -%, based on the weight of the total composition.

22. Epoxy resin composition according to any of the preceding claims 1 to 5, characterized in that the curing agent is present in an amount of 7.5 to 20 wt. -%, based on the weight of the total composition.

23. Epoxy resin composition according to any one of the preceding claims 1 to 5, characterized in that the filler content is 20-80 wt.%, based on the weight of the total composition.

24. Epoxy resin composition according to any one of the preceding claims 1 to 5, characterized in that the filler content is 25 to 75 wt.%, based on the weight of the total composition.

25. Epoxy resin composition according to any one of the preceding claims 1 to 5, characterized in that the filler content is 35-70 wt.%, based on the weight of the total composition.

26. Epoxy resin composition according to claim 4, characterized in that the weight ratio of the first component to the second component is in the range of 0.85 to 1.15.

27. Epoxy resin composition according to the preceding claim 4, characterized in that the weight ratio of the first component to the second component is in the range of 0.9 to 1.1.

28. The epoxy resin composition according to any one of the preceding claims 1 to 5, characterized in that the composition further comprises an auxiliary agent selected from fumed silica, silane coupling agents and rheological aids.

29. The epoxy resin composition according to claim 4, characterized in that the first component comprises 5 to 60wt% of said epoxy resin and 20 to 80wt% of said filler, based on 100 parts by weight of the total weight of the first component; and a second component comprising 10 to 60wt% of the curing agent and 20 to 80wt% of the filler, based on 100 parts by weight of the total weight of the second component.

30. The epoxy resin composition according to claim 29, characterized in that the first component comprises 10 to 50wt% of said epoxy resin based on 100 parts by weight of the total weight of the first component.

31. The epoxy resin composition according to claim 29, characterized in that the first component comprises 25 to 75wt% of said filler, based on 100 parts by weight of the total weight of the first component.

32. The epoxy resin composition according to claim 29, characterized in that the first component comprises 35 to 70wt% of said filler, based on 100 parts by weight of the total weight of the first component.

33. The epoxy resin composition according to claim 29, characterized in that the second component comprises 15 to 50wt% of said curing agent based on 100 parts by weight of the total weight of the second component.

34. The epoxy resin composition according to claim 29, characterized in that the second component comprises 25 to 75wt% of said filler, based on 100 parts by weight of the total weight of the second component.

35. The epoxy resin composition according to claim 29, characterized in that the second component comprises 35 to 70wt% of said filler, based on 100 parts by weight of the total weight of the second component.

36. Epoxy resin composition according to any one of the preceding claims 1 to 5, characterized in that the curing agent does not comprise an aliphatic or aromatic polyamine.

37. Epoxy resin composition according to any of the preceding claims 1 to 5, characterized in that the curing agent comprises at least 90wt% of the combination of the polyamide PA and polyetheramine PEA.

38. Epoxy resin composition according to any one of the preceding claims 1 to 5, characterized in that the curing agent comprises at least 95wt% of the combination of polyamide PA and polyetheramine PEA.

39. Epoxy resin composition according to any of the preceding claims 1 to 5, characterized in that the curing agent consists entirely of the polyamide PA and polyetheramine PEA.

40. An adhesive, sealant or potting adhesive comprising the epoxy resin composition of any of claims 1 to 39.

41. Use of the epoxy resin composition according to any one of the preceding claims 1 to 39 or the adhesive, sealant or potting compound according to claim 40 for electronic products and components thereof.

42. A method of bonding or sealing a substrate comprising:

a) Applying a composition according to any one of claims 1 to 39, or a portion thereof, to a first substrate;

b) Providing a second substrate having optionally applied thereto a composition or portion thereof according to any one of claims 1 to 39;

43. An article comprising the adhesive, sealant or potting adhesive of claim 40, or obtained by the method of claim 42.

44. The article according to claim 43 which is an electronic product and a component thereof.