CA2164915A1 - Curable epoxy resin casting compositions containing core/shell tougheners - Google Patents
Curable epoxy resin casting compositions containing core/shell toughenersInfo
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- CA2164915A1 CA2164915A1 CA002164915A CA2164915A CA2164915A1 CA 2164915 A1 CA2164915 A1 CA 2164915A1 CA 002164915 A CA002164915 A CA 002164915A CA 2164915 A CA2164915 A CA 2164915A CA 2164915 A1 CA2164915 A1 CA 2164915A1
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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
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K9/00—Use of pretreated ingredients
- C08K9/04—Ingredients treated with organic substances
- C08K9/06—Ingredients treated with organic substances with silicon-containing compounds
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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
- C08L51/00—Compositions of graft polymers in which the grafted component is obtained by reactions only involving carbon-to-carbon unsaturated bonds; Compositions of derivatives of such polymers
- C08L51/06—Compositions of graft polymers in which the grafted component is obtained by reactions only involving carbon-to-carbon unsaturated bonds; Compositions of derivatives of such polymers grafted on to homopolymers or copolymers of aliphatic hydrocarbons containing only one carbon-to-carbon double bond
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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
- C08L55/00—Compositions of homopolymers or copolymers, obtained by polymerisation reactions only involving carbon-to-carbon unsaturated bonds, not provided for in groups C08L23/00 - C08L53/00
- C08L55/02—ABS [Acrylonitrile-Butadiene-Styrene] polymers
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- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- Compositions Of Macromolecular Compounds (AREA)
- Epoxy Resins (AREA)
- Structures Or Materials For Encapsulating Or Coating Semiconductor Devices Or Solid State Devices (AREA)
Abstract
Curable epoxy resin casting compositions, comprising a) an aromatic or cycloaliphatic epoxy resin having on average more than one 1,2-epoxy group in the molecule, b) a hardener for the epoxy resin in an amount sufficient to effect a full cure of the epoxy resin, c) a toughener, and d) a finely particulate aluminium oxide coated with a silane of formula I
R4-(n+1) Si (OR )n+1 (I), wherein R is alkyl containing 14 carbon atoms, a phenyl, glycidyloxypropyl, mercapto-propyl or aminopropyl group, R' is alkyl containing 1-12 carbon atoms, and n is 0 or a number from 1 to 3, are admirably suited for encapsulating or coating electrical or electronic components.
R4-(n+1) Si (OR )n+1 (I), wherein R is alkyl containing 14 carbon atoms, a phenyl, glycidyloxypropyl, mercapto-propyl or aminopropyl group, R' is alkyl containing 1-12 carbon atoms, and n is 0 or a number from 1 to 3, are admirably suited for encapsulating or coating electrical or electronic components.
Description
-1-21~1;491~
Curable epoxy resin castin~ compositions containin~ core/shell tougheners The present invention relates to curable epoxy resin casting compositions containing a tough~ne~r and, as filler, an aluminillm oxide coated with a silane, as well as to the use thereof for encapsulating or coating electrical or electronic components. ~ -It is known to modify casting resin compositions based on epoxy resins with a toughener and fillers in order to obtain mouldings having improved fracture to~lghn~.ss. EP-A-0 391 183 discloses that, compared with the use of quartz as f1ller together with a toughener, the use of uncoated aluminium oxide together with a toughener requires a higher loading of filler to obtain mouldings of about equally good fracture toughness. However, casting resin compositions which have a high loading of aluminium oxide have the disadvantage that their processing properties are impaired due to their increased viscosities of the curable casting compositions, and mouldings based on epoxy resins filled in this manner have the additional disadvantage of impaired tensile strength properties.
It has now been found that this disadvantage can be overcome by adding to the epoxy resin casting compositions, in addition to a toughener, a finely particulate aluminium oxide coated with a silane.
Accordingly, the invention relates to curable epoxy resin casting compositions comprising a) an aromatic or cycloaliphatic epoxy resin having on average more than one 1,2-epoxy group in the molecule, b) a hardener for the epoxy resin in an amount suff1cient to effect a full cure of the epoxy resin, c) a toughener, and d) a finely particulate alnminil-m oxide coated with a silane of formula I
R4-(n+l) Si (OR )n+l (I), wherein R is aLkyl cont~ining 1-4 carbon atoms, a phenyl, glycidyloxypropyl, mercapto-propyl or aminopropyl group, R' is alkyl containing 1-12 carbon atoms, and n is 0 or a number from 1 to 3.
Component a) in the novel curable epoxy resin casting compositions can be the customary aromatic or cycloaliphatic epoxy compounds of epoxy resin technology. Typical examples of such epoxy compounds are:
216~15 I) Polyglycidyl and poly(~-methylglycidyl) esters which are obtainable by reacting an aromatic or cycloaliphatic compound containing at least two carboxyl groups in the molecule and epichlorohydrin or ~-methylepichlorohydrin. The reaction is conveniently ~~-carried out in the presence of a base.
Compounds co~t~ining at least two carboxyl groups in the molecule may suitably be aromatic polycarboxylic acids, typically phth~lic acid, isophth~lic acid or terephthalic acid. Examples of cycloaliphatic polycarboxylic acids are tetrahydrophthalic acid, 4-mel}lylle~ahydrophthalic acid, hexahydrophthalic acid or 4-methylhexahydrophthalic acid.
II) Polyglycidyl or poly(~-methylglycidyl) ethers which are obtainable by reacting an aromatic or cycloaliphatic compound cont~ining at least two free alcoholic hydroxyl groups and/or phenolic hydroxyl groups and epichlorohydrin or ~-methylepichlorohydrin, under ~lk~line conditions or in the p-esence of an acid catalyst and subsequent tre~tment with an aLkali.
The glycidyl ethers of this type are typically derived from mononuclear phenols, e.g. from r~so~ ol or hydroquinone, or they are derived from polynuclear phenols such as bis(4-hydroxyphenyl)methane, 4,4'-dihydlo~-yl,iphenyl, bis(4-hyd.~,~yl,henyl)sulfone, 1,1,2,2-tetrakis(4-hydr~,~yphenyl)ethane, 2,2-bis(4-hyd.~"~y~henyl)p~pane, 2,2-bis(3,5-dibromo-4-hydroxyphenyl)plupane, as well as from novolaks oblainablc by con~e.n.~tion ofaldehydes such as formaldehyde, acetaldehyde, chloral or furfuraldehyde, with phenols such as phenol, or with phenols which are substituted in the nucleus by chlorine atoms or Cl-Cgalkyl groups, for example 4-chlorophenol, 2-methylphenol or 4-tert-butylphenol, or by con~en.C~tion with bisphenols of the type cited above.
They may also be derived from cycloaliphatic alcohols such as 1,4-cyclohexane-dimethanol, bis(4-hydroxycyclohexyl)methane or 2,2-bis(4-hydroxycyclohexyl)propane, or they contain aromatic nuclei such as N,N-bis(2-hydroxyethyl)aniline or p,p'-bis(2-hy-droxyethylamino)diphenylmethane.
III) Cycloaliphatic epoxy resins, including bis(2,3-epoxycyclopentyl) ether, 2,3-epoxycy-clopentyl glycidyl ether, 1,2-bis(2,3-epoxycyclopentyloxy)ethane or 3,4-epoxy-cyclohexylmethyl-3 ',4'-epoxycyclohexanecarboxylate.
Curable epoxy resin castin~ compositions containin~ core/shell tougheners The present invention relates to curable epoxy resin casting compositions containing a tough~ne~r and, as filler, an aluminillm oxide coated with a silane, as well as to the use thereof for encapsulating or coating electrical or electronic components. ~ -It is known to modify casting resin compositions based on epoxy resins with a toughener and fillers in order to obtain mouldings having improved fracture to~lghn~.ss. EP-A-0 391 183 discloses that, compared with the use of quartz as f1ller together with a toughener, the use of uncoated aluminium oxide together with a toughener requires a higher loading of filler to obtain mouldings of about equally good fracture toughness. However, casting resin compositions which have a high loading of aluminium oxide have the disadvantage that their processing properties are impaired due to their increased viscosities of the curable casting compositions, and mouldings based on epoxy resins filled in this manner have the additional disadvantage of impaired tensile strength properties.
It has now been found that this disadvantage can be overcome by adding to the epoxy resin casting compositions, in addition to a toughener, a finely particulate aluminium oxide coated with a silane.
Accordingly, the invention relates to curable epoxy resin casting compositions comprising a) an aromatic or cycloaliphatic epoxy resin having on average more than one 1,2-epoxy group in the molecule, b) a hardener for the epoxy resin in an amount suff1cient to effect a full cure of the epoxy resin, c) a toughener, and d) a finely particulate alnminil-m oxide coated with a silane of formula I
R4-(n+l) Si (OR )n+l (I), wherein R is aLkyl cont~ining 1-4 carbon atoms, a phenyl, glycidyloxypropyl, mercapto-propyl or aminopropyl group, R' is alkyl containing 1-12 carbon atoms, and n is 0 or a number from 1 to 3.
Component a) in the novel curable epoxy resin casting compositions can be the customary aromatic or cycloaliphatic epoxy compounds of epoxy resin technology. Typical examples of such epoxy compounds are:
216~15 I) Polyglycidyl and poly(~-methylglycidyl) esters which are obtainable by reacting an aromatic or cycloaliphatic compound containing at least two carboxyl groups in the molecule and epichlorohydrin or ~-methylepichlorohydrin. The reaction is conveniently ~~-carried out in the presence of a base.
Compounds co~t~ining at least two carboxyl groups in the molecule may suitably be aromatic polycarboxylic acids, typically phth~lic acid, isophth~lic acid or terephthalic acid. Examples of cycloaliphatic polycarboxylic acids are tetrahydrophthalic acid, 4-mel}lylle~ahydrophthalic acid, hexahydrophthalic acid or 4-methylhexahydrophthalic acid.
II) Polyglycidyl or poly(~-methylglycidyl) ethers which are obtainable by reacting an aromatic or cycloaliphatic compound cont~ining at least two free alcoholic hydroxyl groups and/or phenolic hydroxyl groups and epichlorohydrin or ~-methylepichlorohydrin, under ~lk~line conditions or in the p-esence of an acid catalyst and subsequent tre~tment with an aLkali.
The glycidyl ethers of this type are typically derived from mononuclear phenols, e.g. from r~so~ ol or hydroquinone, or they are derived from polynuclear phenols such as bis(4-hydroxyphenyl)methane, 4,4'-dihydlo~-yl,iphenyl, bis(4-hyd.~,~yl,henyl)sulfone, 1,1,2,2-tetrakis(4-hydr~,~yphenyl)ethane, 2,2-bis(4-hyd.~"~y~henyl)p~pane, 2,2-bis(3,5-dibromo-4-hydroxyphenyl)plupane, as well as from novolaks oblainablc by con~e.n.~tion ofaldehydes such as formaldehyde, acetaldehyde, chloral or furfuraldehyde, with phenols such as phenol, or with phenols which are substituted in the nucleus by chlorine atoms or Cl-Cgalkyl groups, for example 4-chlorophenol, 2-methylphenol or 4-tert-butylphenol, or by con~en.C~tion with bisphenols of the type cited above.
They may also be derived from cycloaliphatic alcohols such as 1,4-cyclohexane-dimethanol, bis(4-hydroxycyclohexyl)methane or 2,2-bis(4-hydroxycyclohexyl)propane, or they contain aromatic nuclei such as N,N-bis(2-hydroxyethyl)aniline or p,p'-bis(2-hy-droxyethylamino)diphenylmethane.
III) Cycloaliphatic epoxy resins, including bis(2,3-epoxycyclopentyl) ether, 2,3-epoxycy-clopentyl glycidyl ether, 1,2-bis(2,3-epoxycyclopentyloxy)ethane or 3,4-epoxy-cyclohexylmethyl-3 ',4'-epoxycyclohexanecarboxylate.
3 21g4~1~
IV) Poly-(N-glycidyl) compounds obtainable by dehydrochlorination of the reaction products of epichlorohydrin with aromatic amines which contain at least two amino hydrogen atoms. These amines are typically aniline, bis(4-aminophenyl)methane, ~ ~
m-xylyhPnp~ minp or bis(4-methylaminophenyl)methane.
It is also possible to use epoxy resins in which the 1,2-epoxy groups are attached to different hetero atoms or functional groups. These compounds typically comprise the N,N,O-triglycidyl derivative of 4-aminophenol, the glycidyl ether-glycidyl ester of salicylic acid, N-glycidyl-N'-(2-glycidylo~yl~lopyl)-5,5-dimethylhydantoin or 2-glycidyl-oxy- 1 ,3-bis(5,5-dimethyl- 1-glycidylhydantoin-3-yl)propane.
It is also possible to use mixtures of epoxy resins.
For the preparation of the novel curable epoxy resin casting compositions it is pleÇelled to use as component a) a liquid or solid aromatic or cycloaliphatic glycidyl ether or ester, preferably a diglycidyl ether of bisphenol A or bisphenol F, or a cyclo~lir)h~tic diglycidyl ester.
Solid aromatic epoxy resins may suitably be compounds having a m~lting point above room temperature up to about 250C. The melting points of the solid epoxy resins are preferably in the range from 50 to 150C. Such solid epoxy compounds are known, and some are commercially available. Tne advancement products obtained by advAn~nent of liquid polyglycidyl ethers and esters may also be used as solid polyglycidyl ethers and esters.
For the preparation of the novel curable epoxy resin casting compositions, customary hardeners for epoxy resins can 'oe used as component b), typically dicyandiamide, polycarboxylic acids, polycarboxylic anhydrides, polyamines, amine group-cont~ining adducts of amines and polyepoxides, as well as polyols.
Suitable polycarboxylic acids are typicaUy aliphatic polycarboxylic acids such as maleic acid, oxalic acid, succinic acid, nonyl- or dodecylsuccinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid or dimerised or trimerised linoleic acid, cycloaliphatic polycarboxylic acids such as tetrahydrophthalic acid, methylenedomethyl-enetetrahydrophthalic acid, hexachloroendomethylenetetrahydrophthalic acid, 21~4gl5 4-methyltetrahydrophthalic acid, hexahydrophthalic acid, or 4-methylhexahydrophthalic acid, or aromatic polycarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, pyromellitic acid or benzophenone-3,3',4,4'-tetracarboxylic acid, as well as the anhydrides of these polycarboxylic acids.
Polyamines suitable for use in the novel curable epoxy resin casting compositions are aliphatic, cycloaliphatic, aromatic or heterocyclic ~minP.s, including ethylene~i~minP, 1,2-propane~i~mine, 1,3-propane(li~minP., N,N-diethylethylene~ mine, hexamethylenedi-amine, diethylenetri~mine, triethylentetramine, tetraethylenepentamine, N-(2-hydroxyethyl)-, N-(2-hydroxypropyl)- and N-(2-cyanoethyl)diethyltriamine, 2,2,4-trimethyl-1,6-hexane~ mine, 2,3,3,-trimethyl-1,6-hexanedi~mine, N,N-dimethyl- and N,N-diethyl-1,3-propane~ minP, ethanolamine, m- and p-phenylene~i~minP"
bis(4-aminophenyl)methane, aniline-formaldehyde resins, bis(4-aminophenyl)sulfone, m-xylylene(li~minP, bis(4-aminocyclohexyl)methane, 2,2-bis(4-aminocyclohexyl)propane, 2,2-bis(4-amino-3-methylcyclohexyl)propane, 3-aminomethyl-3,5,5-trimethylcyclo-hexylamine (isophoronecli~mine) and N-(2-aminoethyl)piperazine, and, as polyamino-~miS~es~ typically those from aliphatic polyamines and dimerised or trimerised fatty acids.
Aliphatic polyols suitable for use in the novel curable epoxy resin casting compositions are typically ethylene glycol, diethylene glycol and higher poly(oxyethylene) glycols, 1,2-propanediol or poly(oxypropylene) glycols, 1,3-propanediol, 1,4-butanediol, poly(oxy-tetramethylene) glycols, l,5-pentanediol, 1,6-hPx~n~-iiol, 2,4,6-hexanetriol, glycerol, l,l,l-trimethylolpropane, pentaerythritol or sorbitol.
Aromatdc polyols suitable for use in the novel curable epoxy resin casting composidons include mononuclear phenols such as resorcinol, hydroquinone, N,N-bis(2-hydroxyethyl)-aniline, or polynuclear phenols, such as p,p'-bis(2-hydroxyethylamino)diphenylmethane, bis(4-hydroxyphenyl)methane, 4,4'-dihydroxybiphenyl, bis(4-hydroxyphenyl)sulfone, 1,1,2,2-tetrakis(4-hydroxyphenyl)ethane, 2,2-bis(4-hydroxyphenyl)propane, 2,2-bis(3,5-dibromo-4-hydroxyphenyl)propane, as well as novolaks obtainable by condensation of aldehydes, typically formaldehyde, acetaldehyde, chloral or furfuraldehyde, with phenols such as phenol, or with phenols which are substituted in the nucleus by chlorine atoms or Cl-Cgalkyl groups, for example 4-chlorophenol, 2-methylphenol, or 4-tert-butylphenol, or by condensation with bisphenols, such as those of the indicated type.
Catalytic hardeners can also be used for preparing the novel curable epoxy resin casting 2~64~1~
compositions, typically tertiary amines such as 2,4,6-tris(dimethylaminoethyl)phenol and other ~lanni~h bases, N-benzyldimethylamine and triethanolamine; aLkali metal alkoxides of alcohols, typically the sodium alcoholate of 2,4-dihydroxy-3-hydroxymethylpen~le;
tin salts of alkanoic acids, typically tin octanoate; Friedel-Crafts catalysts such as boron ~ ~
trifluoride and the complexes and chelates thereof which are obtained by reacting boron --trifluoride with e.g. 1,3-diketones. If catalytic hardeners are used, they are preferably suspended in the touEhPnPr~ It is p,erel,~d to use 0.1 to 10 parts by weight of hardener catalyst per 10 parts by weight of toughener.
Mixtures of hardeners can also be used for the novel casting resin compositions, provided they do not react with each other.
Component b) of the novel casting resin compositions is preferably a polycarboxylic anhydride, more particularly an aromatic or cycloaliphatic polycarboxylic anhydride.
Suitable accelerators may also be used for curing the novel casting resin compositions.
When, for e~mplç, dicy~n~i~mide, polycarboxylic acids and their anhydrides are used, the accelerators can be tertiary amines or their salts, quaternary ammonium compounds or aLkali metal alkoxides.
TouEhPnPrs c) suitable for use in the novel curable epoxy resin casting compositions are typically the elastomers or el~tomPr-conlAil-ing graft polymers known to those skilled in the art as rubber touEhP.ners. The toughP.nP.r.~ may also be solid or liquid in the initial state.
In particular, the novel curable epoxy resin casting compositions contain a solid touEhPner. Solid touEheners typically comprise the graft polymers disclosed, inter alia, in US-A-3 496 250 and in US-A-4 366 289, as well as the corelshell polymers disclosed in EP-A-0-045 357 and in US-A-4 419 496.
Solid tougheners have the advantage that the particle size and the amount of toughP.tlçr phase in the curable epoxy resin casting compositions are predetermined. When using liquid tougheners, the toughening phase does not form until during the cure with the epoxy resin.
Graft polymers are typically methacrylate/butadiene-styrene polymers, acrylate-meth-acrylate/butadiene-styrene polymers or acrylonitrile/butadiene-styrene polymers.
~6~9~5 Core/shell polymers normally have a soft core of an elastomeric material which is insoluble in the epoxy resin matrix. Grafted thereon is a shell of polymeric m~te~i~l which preferably contains no reactive groups. The core/shell polymer may also be a so-called ~ ~
multi-core/shell polymer, conveniently one having the structure soft core, hard shell, soft shell and hard shell. Such polymers are disclosed, inter alia, in GB-A-2 039 496.
In a particularly preferred embodiment of the invention, the curable epoxy resin casting compositions contain a core/shell polymer.
Examples of elastomers which may be used as core m~te~i~l are polybutadiene, poly-acrylates and polymethacrylates and their co- or terpolymers with poly~,~yl~ne, polyacrylonitrile or polysulfide.
The core m~teri~l preferably contains polybutadiene or polybutylacrylate.
Typical examples of polymeric shell m~te~ are polystyrene, polyacrylate and polymethacrylate mono-, co- or terpolymers or styrene/acrylonitrile/glycidyl methacrylate terpolymers.
It is pl~felled to use polymethyl meth~crylate as shell m~teri~l The size of such core/shell particles is conveniently 0.05 to 30 ~m, preferably 0.05 to 15 llm. It is preferred to use core/shell particles having a size smaller than 1 llm.
The core/shell polymers can be prepared by the method described in US-A-4 419 496 or EP-A-O 045 357.
The novel casting compositions preferably contain tougheners containing no reactive groups that could react with the epoxy resin.
It is preferred to use core/shell polymers which contain a core of polybutadiene or polybutadiene/polystyrene. This core material is preferably partially crosslinked. Further core materials are polyacrylates and polymethacrylates, preferably polymethyl acrylates and polymethyl methacrylates and their co- and terpolymers.
-7- 21~491$
The shell consists preferably of polymers based on methyl methacrylate, cyclohexyl methacrylate, butyl acrylate, styrene or methacrylonitrile.
The amount of toughener in the novel curable epoxy resin casting compositions is ~~~
preferably up to to 80 % by weight, most preferably up to 50 % by weight, based on the epoxy resin.
Components a) and c) in the novel curable epoxy resin casting compositions are preferably together in the form of a suspen~ion which is also storage-stable and which contains the toughener in homogeneous dispersion. Such suspensions can be prepared by either 1) when using liquid epoxy resins, adding the aqueous emulsion of the tou~hP.n~r, with or without a solvent, to the epoxy resin, and removing the water or mixture of water and solvent by vacuum distillation, or 2) when using solid epoxy resins, fusing the solid epoxy resin or dissolving it in a suitable solvent and adding the aqueous emulsion of the toughPnPr to the epoxy resin, andsubsequently removing the water or mixture of water and solvent by vacuum ~ till~tion.
Such storage-stable suspensions comprising an epoxy hardener and a tou.~hPnPr suspended therein are suitable in simple and practical manner for the preparation of curable epoxy resin formulations in which the toughPnP.r is homogeneously dispersed, which formulations may also be in the form of suspensions. From the processing aspect, the novel suspensions may be regarded as a simple means of plep~ing curable epoxy resin formulations in which a toughPnPr present therein is homogeneously ~i~persed. Inaddition, the preparation of such epoxy resin formulations makes it possible to achieve a certain con.~ictency of quality in advantageous manner.
Finely particulate ~luminium oxide, which may be used for coating with a silane of formula I, is commercially available, e.g. having a particle size distribution of c. 0.1 to c.
120 llm.
For the preparation of component d) it is preferred to use an ~lnminium oxide having a particle size distribution of 1.0 to 60 ,um.
The silanes of formula I used for coating the aluminium oxide are commonly known, e.g.
from the product information leaflet "Organofunctional Silanes - A Profile" (1981) of Union Carbide, from the Journal of Materials Science 18, 1983, pages 208-216, and from 2~6~915 the "Product Information Leaflet 1985" of Shin Etsu, and some are commercially available, e.g. the ~-glycidylo~y~Jropyltrimethoxysilane and the 3~-mercaptopropyl-trimethoxysilane, supplied by Union Carbide and Shin Etsu.
For coating the ~l11mini11m oxide it is preferred to use a silane of formula I, wherein R is a methyl, ethyl, phenyl, glycidylo~-y~lopyl, mercaptopropyl or aminopropyl group, R' is aL~cyl cont~ining 1-4 carbon atoms, and n is 2.
The finely particulate ~ minium oxide is coated with a silane of formula I in known manner, typically by placing the fillers in a ball mill and adding the silane during mi11ing, liquid silanes conveniently being added to the aluminium oxide using a suitable metering device, pipette or syringe. After milling the mixture for several hours, the balls are removed by sieving through a wide-meshed sieve.
Preferred coating compounds are y-glycidyloxypropyltrimethoxysilane or ~-mercapto-propyltrimethoxysilane.
The amount of component d) in the novel curable epoxy resin casting compositions is usually from 20 to 80% by weight, preferably from 40 to 80% by weight, more preferably from 55 to 70% by weight, based on the total epoxy resin casting composition.
If desired, the novel epoxy resin casting compositions may additionally contain further finely dispersed fillers. These may be the standard fillers of epoxy resin technology, typically quartz powder or powder from fused silica, mica, kaolin, dolomite, wol1~tonite, glass fibres, ~l~phi~e or carbon black.
The novel curable epoxy resin casting compositions are prepared by per se known methods using known mixer aggregates such as stirrers, knPadçr~, roll mills or, in the case of solid substances, in dry mixers.
The novel curable epoxy resin casting compositions are cured to coatings, encapsulations or the like in the standard known manner of epoxy resin technology, as described, inter alia, in the "Handbook of Epoxy Resins", 1967, by H. Lee and K. Neville.
The novel curable epoxy resin casting compositions are admirably suited for use as coating materials and as encapsulating systems for electrical and electronic components, 9 21~4915 in particular for electronic components requiring good fracture-mechanical prope,lies in the medium voltage range and, more particularly, in the high voltage range, such as converters or electrical insulators.
In the following Examples the following suspensions consisting of an epoxy resin and a core/shell polymer or of epoxy resins modified with a core/shell polymer, as well as the following fillers coated with a silane, are used.
Suspension A: (Diglycidyl ether-core/shell polymer suspension) a) Preparation of a core/shell polymer:
202.7 g of polybut~ .n~. latex (BL 2004 K, supplied by Bayer AG), having a solids content of 59.2 %, and 397.3 g of deionised water are placed, under nitrogen, in a 1 litre ground glass flask equipped with double jacket, glass anchor stirrer, thermometer, condenser, rotary thermostat and gas inlet, and stirred at 100 rpm. The mixture is heated to 80C + 1C. After about 55 miml~es (min), the tempela~ in the vessel is 80C. Then the dropwise addition of 120.0 g of (li~till~d methyl methacrylate (purum, supplied by Fluka, Swit7Prl~nd) and of a solution of 4.0 g of potassium peroxide ~liclllf~te and 3.5 g of sodium dodecylben7enesulfonate in 110 ml of distilled water is commenced. After 3.5 hours (h), a homogeneous white emulsion is obtained. After altogether 6 h and 10 min, the addition of methyl methacrylate and of the initiator is complete.
Stirring is continued for a further 2 h at 80C. At the end of this time, 3 ml of a 20 ~o emulsion of n-octadecyl 3-(3,5-di-tert-butyl-4-hyd,o~y~henyl)propionate are added to the homogeneous white emulsion, and the entire batch is then cooled to room temperature (RT). The emulsion is likewise homogeneous and white at RT. It is filtered through glass wool. No agglomerates are present. The emulsion is diluted to 865 g, corresponding to a solids content of 27.2 %. The emulsion so obtained is used as toughe~er.
b) A 2 litre ground glass flask equipped with glass anchor stirrer, thermometer, condenser, distillation tube with receiver and vacuum connection is charged with 600 g of liquid diglycidyl ether of bisphenol A having an epoxy value of 5.42 equivalents/kg, and 220.6 g of the aqueous emulsion of the core/shell polymer prepared according to Example Aa) are added and the batch is stirred for 15 min. The homogeneous mixture is then heated to c. 80C and evacuated to 150-200 mbar such that water distills from the mixture. Towards the end of di~t~ tion the pressure is lowered to 40-50 mbar, and residual water is removed over c. 30 min. The resultant homogeneous white suspension is readily stirrable at 80C
and is drawn off after cooling to 50C.
Yield: 656 g epoxy value: 4.7-5.0 equivalents/kg content of toughener: 10 phr*, based on the epoxy resin *phr = parts per hundred (parts by weight per 100 parts by weight of epoxy resin).
Suspension B: (Diglyicdyl ester-core/shell polymer suspension) a) Preparation of a core/shell polymer as described for suspension Aa). An emulsion having a solids content of 27.2 % is obtained.
b) The preparation of the diglycidyl ester-core/shell polymer suspension as described for suspension Ab) is repeated, but using as epoxy resin only 600 g of diglycidyl ester of cyclohexane-1,2-dicarboxylic acid having an epoxy value of 5.6-6.2 equivalents/kg. A
readily stirrable suspension is obtained.
epoxy value: 5.3 equivalents/kg content of toughener: 10 phr.
SusPension C: (Diglycidyl ether-coretshell polymer suspension) a) Preparation of a core/shell polymer as described for suspension Aa).
An emulsion having a solids content of 28.15% is obtained.
b) 1050.0 g of a solid diglycidyl ether of bisphenol A modified with 0.84 % by weight of nonylphenol hydroxyethyl ether and having an epoxy value of 2.55-2.7 equivalents/kg and a me!tin~ range of 35-50C is heated to c. 130C, without stirring, in a 3 litre ground glass flask, equipped as described in Example A. Then the emulsion obtained according to Example a) is added at this temperature and stirred for 15 minutes. The mixture is evacuated to 650-700 mbar and the buLk of the water is distilled off under this Va~,UWII
over about 2 h through the (li.ctill~tion tube and collected in the receiver. Further evacuation is effected cautiously, and the reaction mass becomes temporarily highly viscous. At the conclusion, the reaction mass is stirred for 30 min at 130C/20-30 mbar and then for 15 min under high vacuum (0.1-0.2 mbar). The result~nt white, turbid viscous product is poured on to coated paper at c. 120C. After cooling, the solidified product is mechanically comminuted.
epoxy value: 2.40 equivalents/kg content of toughener: 10 phr.
216~91~
Coated Al2O3 (filler I) 1000 g of ~ minium oxide are put into a porcelain ball mill filled to about 1/3 of its volume with ceramic balls. Then 5 g of ~-glycidyloxypropyltrimethoxysilane are added and the mixture is milled for 15 h. The balls are then removed by sieving through a wide-meshed sh~king sieve. The aluminium oxide coated in this manner is used in this form in the Examples.
Example 1 With stirring, 100 g of suspension A are homogenised with 87 g of a modified methyl-hexahydrophthalic anhydride, (commercially available under the product name "XB
5996" from CIBA-GEIGY AG) in the temperature range from 50 to 60C. To this ~
are then added 560 g of filler I. The mixture is heated, with stirring, to 80C, evacuated for 7 minutes under a pressure of 3 mbar and cast in plates preheated to 100C. The gelation time of the curable epoxy resin composition is 8 min/21sec at 140C. The curable mixture has a filler content of 60% by weight, based on the total mixture. The following p~pel lies of the test samples are determined after curing for 2 h at 100C, for 10 h at 140C and for 2hat 160C:
Tg value (determined by DSC~)) = 150C
flexural strength (acc. to ISO 178) = 131 N/mm2 flexural elongation = 2.34 %
modulus of elasticity in the flexural test = 7721 N/mm2 tensile strength (according to ISO R527) = 82 N/mm2 Illtim~te elongation = 2.28 %
modulus of elasticity in the tensile test = 7392 N/mm2 double torsion test (acc. to DIN 51 221) fracture toughne~S Glc = 447 J/m2 critical stress intensity factor KlC
(fracture toughness) = 1.95 MPa~
~) Differential Scanning Calorimeter ~i6491S
`_ Example 2 100 g of suspension B, 90 g of methylhexahydrophthalic anhydride and 0.53 g of benzyldimethylamine are weighed together cold and mixed, with stirring, in the temperature range from c. 50 to 60C. To this mixture are added 391 g of filler I and the temperature is raised to 80C. The mixture is homogenised and then evacuated, with stirring, at 3 mbar for 10 min and then cast in moulds preheated to 100C. The casting composition is cured for 2 h at 100C and for 16 h at 140C. The test samples have the following properties:
Tg value (determined by DSC) = 128C
flexural strength (acc.to ISO 178) = 128 N/mm2 flexuralelongation = 1.56%
modulus of elasticity in the flexural test = 10972 N/mm2 double torsion test (acc. to DIN 51 221) fracture toughn~Ss G lC = 521 J/m2 critical stress intensity factor KlclC = 2.51 MPa~.
Example 3 100 g of suspension C are placed in a vessel at room temperature and heated to 120C. To this suspension are added 45 g of a hardener mixture con.~i~ting of 35 parts by weight of phthalic anhydride and 65 parts by weight of tetrahydrophthalic anhydride, and the entire batch is then homogenised. Into the clear solution are stirred 218 g of filler I in increments. After 15 min the mixture is degassed for 3 min at 3 mbar and then cast in moulds preheated to 100C. The casting composition is cured for 16 h at 140C. The test samples have the following properties:
Tg value (determined by DSC) = 133C
flexural strength (acc. to ISO 178) = 150 N/mm2 flexural elongation (acc. to ISO 178) = 2.79 %
modulus of elasticity in the flexural test = 8257 N/mm2 double torsion test (acc. to DIN 51 221) fracture toughness Glc = 777 J/m2 21649iS
critical stress intensity factor KlC = 2.67 MPa~.
IV) Poly-(N-glycidyl) compounds obtainable by dehydrochlorination of the reaction products of epichlorohydrin with aromatic amines which contain at least two amino hydrogen atoms. These amines are typically aniline, bis(4-aminophenyl)methane, ~ ~
m-xylyhPnp~ minp or bis(4-methylaminophenyl)methane.
It is also possible to use epoxy resins in which the 1,2-epoxy groups are attached to different hetero atoms or functional groups. These compounds typically comprise the N,N,O-triglycidyl derivative of 4-aminophenol, the glycidyl ether-glycidyl ester of salicylic acid, N-glycidyl-N'-(2-glycidylo~yl~lopyl)-5,5-dimethylhydantoin or 2-glycidyl-oxy- 1 ,3-bis(5,5-dimethyl- 1-glycidylhydantoin-3-yl)propane.
It is also possible to use mixtures of epoxy resins.
For the preparation of the novel curable epoxy resin casting compositions it is pleÇelled to use as component a) a liquid or solid aromatic or cycloaliphatic glycidyl ether or ester, preferably a diglycidyl ether of bisphenol A or bisphenol F, or a cyclo~lir)h~tic diglycidyl ester.
Solid aromatic epoxy resins may suitably be compounds having a m~lting point above room temperature up to about 250C. The melting points of the solid epoxy resins are preferably in the range from 50 to 150C. Such solid epoxy compounds are known, and some are commercially available. Tne advancement products obtained by advAn~nent of liquid polyglycidyl ethers and esters may also be used as solid polyglycidyl ethers and esters.
For the preparation of the novel curable epoxy resin casting compositions, customary hardeners for epoxy resins can 'oe used as component b), typically dicyandiamide, polycarboxylic acids, polycarboxylic anhydrides, polyamines, amine group-cont~ining adducts of amines and polyepoxides, as well as polyols.
Suitable polycarboxylic acids are typicaUy aliphatic polycarboxylic acids such as maleic acid, oxalic acid, succinic acid, nonyl- or dodecylsuccinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid or dimerised or trimerised linoleic acid, cycloaliphatic polycarboxylic acids such as tetrahydrophthalic acid, methylenedomethyl-enetetrahydrophthalic acid, hexachloroendomethylenetetrahydrophthalic acid, 21~4gl5 4-methyltetrahydrophthalic acid, hexahydrophthalic acid, or 4-methylhexahydrophthalic acid, or aromatic polycarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, pyromellitic acid or benzophenone-3,3',4,4'-tetracarboxylic acid, as well as the anhydrides of these polycarboxylic acids.
Polyamines suitable for use in the novel curable epoxy resin casting compositions are aliphatic, cycloaliphatic, aromatic or heterocyclic ~minP.s, including ethylene~i~minP, 1,2-propane~i~mine, 1,3-propane(li~minP., N,N-diethylethylene~ mine, hexamethylenedi-amine, diethylenetri~mine, triethylentetramine, tetraethylenepentamine, N-(2-hydroxyethyl)-, N-(2-hydroxypropyl)- and N-(2-cyanoethyl)diethyltriamine, 2,2,4-trimethyl-1,6-hexane~ mine, 2,3,3,-trimethyl-1,6-hexanedi~mine, N,N-dimethyl- and N,N-diethyl-1,3-propane~ minP, ethanolamine, m- and p-phenylene~i~minP"
bis(4-aminophenyl)methane, aniline-formaldehyde resins, bis(4-aminophenyl)sulfone, m-xylylene(li~minP, bis(4-aminocyclohexyl)methane, 2,2-bis(4-aminocyclohexyl)propane, 2,2-bis(4-amino-3-methylcyclohexyl)propane, 3-aminomethyl-3,5,5-trimethylcyclo-hexylamine (isophoronecli~mine) and N-(2-aminoethyl)piperazine, and, as polyamino-~miS~es~ typically those from aliphatic polyamines and dimerised or trimerised fatty acids.
Aliphatic polyols suitable for use in the novel curable epoxy resin casting compositions are typically ethylene glycol, diethylene glycol and higher poly(oxyethylene) glycols, 1,2-propanediol or poly(oxypropylene) glycols, 1,3-propanediol, 1,4-butanediol, poly(oxy-tetramethylene) glycols, l,5-pentanediol, 1,6-hPx~n~-iiol, 2,4,6-hexanetriol, glycerol, l,l,l-trimethylolpropane, pentaerythritol or sorbitol.
Aromatdc polyols suitable for use in the novel curable epoxy resin casting composidons include mononuclear phenols such as resorcinol, hydroquinone, N,N-bis(2-hydroxyethyl)-aniline, or polynuclear phenols, such as p,p'-bis(2-hydroxyethylamino)diphenylmethane, bis(4-hydroxyphenyl)methane, 4,4'-dihydroxybiphenyl, bis(4-hydroxyphenyl)sulfone, 1,1,2,2-tetrakis(4-hydroxyphenyl)ethane, 2,2-bis(4-hydroxyphenyl)propane, 2,2-bis(3,5-dibromo-4-hydroxyphenyl)propane, as well as novolaks obtainable by condensation of aldehydes, typically formaldehyde, acetaldehyde, chloral or furfuraldehyde, with phenols such as phenol, or with phenols which are substituted in the nucleus by chlorine atoms or Cl-Cgalkyl groups, for example 4-chlorophenol, 2-methylphenol, or 4-tert-butylphenol, or by condensation with bisphenols, such as those of the indicated type.
Catalytic hardeners can also be used for preparing the novel curable epoxy resin casting 2~64~1~
compositions, typically tertiary amines such as 2,4,6-tris(dimethylaminoethyl)phenol and other ~lanni~h bases, N-benzyldimethylamine and triethanolamine; aLkali metal alkoxides of alcohols, typically the sodium alcoholate of 2,4-dihydroxy-3-hydroxymethylpen~le;
tin salts of alkanoic acids, typically tin octanoate; Friedel-Crafts catalysts such as boron ~ ~
trifluoride and the complexes and chelates thereof which are obtained by reacting boron --trifluoride with e.g. 1,3-diketones. If catalytic hardeners are used, they are preferably suspended in the touEhPnPr~ It is p,erel,~d to use 0.1 to 10 parts by weight of hardener catalyst per 10 parts by weight of toughener.
Mixtures of hardeners can also be used for the novel casting resin compositions, provided they do not react with each other.
Component b) of the novel casting resin compositions is preferably a polycarboxylic anhydride, more particularly an aromatic or cycloaliphatic polycarboxylic anhydride.
Suitable accelerators may also be used for curing the novel casting resin compositions.
When, for e~mplç, dicy~n~i~mide, polycarboxylic acids and their anhydrides are used, the accelerators can be tertiary amines or their salts, quaternary ammonium compounds or aLkali metal alkoxides.
TouEhPnPrs c) suitable for use in the novel curable epoxy resin casting compositions are typically the elastomers or el~tomPr-conlAil-ing graft polymers known to those skilled in the art as rubber touEhP.ners. The toughP.nP.r.~ may also be solid or liquid in the initial state.
In particular, the novel curable epoxy resin casting compositions contain a solid touEhPner. Solid touEheners typically comprise the graft polymers disclosed, inter alia, in US-A-3 496 250 and in US-A-4 366 289, as well as the corelshell polymers disclosed in EP-A-0-045 357 and in US-A-4 419 496.
Solid tougheners have the advantage that the particle size and the amount of toughP.tlçr phase in the curable epoxy resin casting compositions are predetermined. When using liquid tougheners, the toughening phase does not form until during the cure with the epoxy resin.
Graft polymers are typically methacrylate/butadiene-styrene polymers, acrylate-meth-acrylate/butadiene-styrene polymers or acrylonitrile/butadiene-styrene polymers.
~6~9~5 Core/shell polymers normally have a soft core of an elastomeric material which is insoluble in the epoxy resin matrix. Grafted thereon is a shell of polymeric m~te~i~l which preferably contains no reactive groups. The core/shell polymer may also be a so-called ~ ~
multi-core/shell polymer, conveniently one having the structure soft core, hard shell, soft shell and hard shell. Such polymers are disclosed, inter alia, in GB-A-2 039 496.
In a particularly preferred embodiment of the invention, the curable epoxy resin casting compositions contain a core/shell polymer.
Examples of elastomers which may be used as core m~te~i~l are polybutadiene, poly-acrylates and polymethacrylates and their co- or terpolymers with poly~,~yl~ne, polyacrylonitrile or polysulfide.
The core m~teri~l preferably contains polybutadiene or polybutylacrylate.
Typical examples of polymeric shell m~te~ are polystyrene, polyacrylate and polymethacrylate mono-, co- or terpolymers or styrene/acrylonitrile/glycidyl methacrylate terpolymers.
It is pl~felled to use polymethyl meth~crylate as shell m~teri~l The size of such core/shell particles is conveniently 0.05 to 30 ~m, preferably 0.05 to 15 llm. It is preferred to use core/shell particles having a size smaller than 1 llm.
The core/shell polymers can be prepared by the method described in US-A-4 419 496 or EP-A-O 045 357.
The novel casting compositions preferably contain tougheners containing no reactive groups that could react with the epoxy resin.
It is preferred to use core/shell polymers which contain a core of polybutadiene or polybutadiene/polystyrene. This core material is preferably partially crosslinked. Further core materials are polyacrylates and polymethacrylates, preferably polymethyl acrylates and polymethyl methacrylates and their co- and terpolymers.
-7- 21~491$
The shell consists preferably of polymers based on methyl methacrylate, cyclohexyl methacrylate, butyl acrylate, styrene or methacrylonitrile.
The amount of toughener in the novel curable epoxy resin casting compositions is ~~~
preferably up to to 80 % by weight, most preferably up to 50 % by weight, based on the epoxy resin.
Components a) and c) in the novel curable epoxy resin casting compositions are preferably together in the form of a suspen~ion which is also storage-stable and which contains the toughener in homogeneous dispersion. Such suspensions can be prepared by either 1) when using liquid epoxy resins, adding the aqueous emulsion of the tou~hP.n~r, with or without a solvent, to the epoxy resin, and removing the water or mixture of water and solvent by vacuum distillation, or 2) when using solid epoxy resins, fusing the solid epoxy resin or dissolving it in a suitable solvent and adding the aqueous emulsion of the toughPnPr to the epoxy resin, andsubsequently removing the water or mixture of water and solvent by vacuum ~ till~tion.
Such storage-stable suspensions comprising an epoxy hardener and a tou.~hPnPr suspended therein are suitable in simple and practical manner for the preparation of curable epoxy resin formulations in which the toughPnP.r is homogeneously dispersed, which formulations may also be in the form of suspensions. From the processing aspect, the novel suspensions may be regarded as a simple means of plep~ing curable epoxy resin formulations in which a toughPnPr present therein is homogeneously ~i~persed. Inaddition, the preparation of such epoxy resin formulations makes it possible to achieve a certain con.~ictency of quality in advantageous manner.
Finely particulate ~luminium oxide, which may be used for coating with a silane of formula I, is commercially available, e.g. having a particle size distribution of c. 0.1 to c.
120 llm.
For the preparation of component d) it is preferred to use an ~lnminium oxide having a particle size distribution of 1.0 to 60 ,um.
The silanes of formula I used for coating the aluminium oxide are commonly known, e.g.
from the product information leaflet "Organofunctional Silanes - A Profile" (1981) of Union Carbide, from the Journal of Materials Science 18, 1983, pages 208-216, and from 2~6~915 the "Product Information Leaflet 1985" of Shin Etsu, and some are commercially available, e.g. the ~-glycidylo~y~Jropyltrimethoxysilane and the 3~-mercaptopropyl-trimethoxysilane, supplied by Union Carbide and Shin Etsu.
For coating the ~l11mini11m oxide it is preferred to use a silane of formula I, wherein R is a methyl, ethyl, phenyl, glycidylo~-y~lopyl, mercaptopropyl or aminopropyl group, R' is aL~cyl cont~ining 1-4 carbon atoms, and n is 2.
The finely particulate ~ minium oxide is coated with a silane of formula I in known manner, typically by placing the fillers in a ball mill and adding the silane during mi11ing, liquid silanes conveniently being added to the aluminium oxide using a suitable metering device, pipette or syringe. After milling the mixture for several hours, the balls are removed by sieving through a wide-meshed sieve.
Preferred coating compounds are y-glycidyloxypropyltrimethoxysilane or ~-mercapto-propyltrimethoxysilane.
The amount of component d) in the novel curable epoxy resin casting compositions is usually from 20 to 80% by weight, preferably from 40 to 80% by weight, more preferably from 55 to 70% by weight, based on the total epoxy resin casting composition.
If desired, the novel epoxy resin casting compositions may additionally contain further finely dispersed fillers. These may be the standard fillers of epoxy resin technology, typically quartz powder or powder from fused silica, mica, kaolin, dolomite, wol1~tonite, glass fibres, ~l~phi~e or carbon black.
The novel curable epoxy resin casting compositions are prepared by per se known methods using known mixer aggregates such as stirrers, knPadçr~, roll mills or, in the case of solid substances, in dry mixers.
The novel curable epoxy resin casting compositions are cured to coatings, encapsulations or the like in the standard known manner of epoxy resin technology, as described, inter alia, in the "Handbook of Epoxy Resins", 1967, by H. Lee and K. Neville.
The novel curable epoxy resin casting compositions are admirably suited for use as coating materials and as encapsulating systems for electrical and electronic components, 9 21~4915 in particular for electronic components requiring good fracture-mechanical prope,lies in the medium voltage range and, more particularly, in the high voltage range, such as converters or electrical insulators.
In the following Examples the following suspensions consisting of an epoxy resin and a core/shell polymer or of epoxy resins modified with a core/shell polymer, as well as the following fillers coated with a silane, are used.
Suspension A: (Diglycidyl ether-core/shell polymer suspension) a) Preparation of a core/shell polymer:
202.7 g of polybut~ .n~. latex (BL 2004 K, supplied by Bayer AG), having a solids content of 59.2 %, and 397.3 g of deionised water are placed, under nitrogen, in a 1 litre ground glass flask equipped with double jacket, glass anchor stirrer, thermometer, condenser, rotary thermostat and gas inlet, and stirred at 100 rpm. The mixture is heated to 80C + 1C. After about 55 miml~es (min), the tempela~ in the vessel is 80C. Then the dropwise addition of 120.0 g of (li~till~d methyl methacrylate (purum, supplied by Fluka, Swit7Prl~nd) and of a solution of 4.0 g of potassium peroxide ~liclllf~te and 3.5 g of sodium dodecylben7enesulfonate in 110 ml of distilled water is commenced. After 3.5 hours (h), a homogeneous white emulsion is obtained. After altogether 6 h and 10 min, the addition of methyl methacrylate and of the initiator is complete.
Stirring is continued for a further 2 h at 80C. At the end of this time, 3 ml of a 20 ~o emulsion of n-octadecyl 3-(3,5-di-tert-butyl-4-hyd,o~y~henyl)propionate are added to the homogeneous white emulsion, and the entire batch is then cooled to room temperature (RT). The emulsion is likewise homogeneous and white at RT. It is filtered through glass wool. No agglomerates are present. The emulsion is diluted to 865 g, corresponding to a solids content of 27.2 %. The emulsion so obtained is used as toughe~er.
b) A 2 litre ground glass flask equipped with glass anchor stirrer, thermometer, condenser, distillation tube with receiver and vacuum connection is charged with 600 g of liquid diglycidyl ether of bisphenol A having an epoxy value of 5.42 equivalents/kg, and 220.6 g of the aqueous emulsion of the core/shell polymer prepared according to Example Aa) are added and the batch is stirred for 15 min. The homogeneous mixture is then heated to c. 80C and evacuated to 150-200 mbar such that water distills from the mixture. Towards the end of di~t~ tion the pressure is lowered to 40-50 mbar, and residual water is removed over c. 30 min. The resultant homogeneous white suspension is readily stirrable at 80C
and is drawn off after cooling to 50C.
Yield: 656 g epoxy value: 4.7-5.0 equivalents/kg content of toughener: 10 phr*, based on the epoxy resin *phr = parts per hundred (parts by weight per 100 parts by weight of epoxy resin).
Suspension B: (Diglyicdyl ester-core/shell polymer suspension) a) Preparation of a core/shell polymer as described for suspension Aa). An emulsion having a solids content of 27.2 % is obtained.
b) The preparation of the diglycidyl ester-core/shell polymer suspension as described for suspension Ab) is repeated, but using as epoxy resin only 600 g of diglycidyl ester of cyclohexane-1,2-dicarboxylic acid having an epoxy value of 5.6-6.2 equivalents/kg. A
readily stirrable suspension is obtained.
epoxy value: 5.3 equivalents/kg content of toughener: 10 phr.
SusPension C: (Diglycidyl ether-coretshell polymer suspension) a) Preparation of a core/shell polymer as described for suspension Aa).
An emulsion having a solids content of 28.15% is obtained.
b) 1050.0 g of a solid diglycidyl ether of bisphenol A modified with 0.84 % by weight of nonylphenol hydroxyethyl ether and having an epoxy value of 2.55-2.7 equivalents/kg and a me!tin~ range of 35-50C is heated to c. 130C, without stirring, in a 3 litre ground glass flask, equipped as described in Example A. Then the emulsion obtained according to Example a) is added at this temperature and stirred for 15 minutes. The mixture is evacuated to 650-700 mbar and the buLk of the water is distilled off under this Va~,UWII
over about 2 h through the (li.ctill~tion tube and collected in the receiver. Further evacuation is effected cautiously, and the reaction mass becomes temporarily highly viscous. At the conclusion, the reaction mass is stirred for 30 min at 130C/20-30 mbar and then for 15 min under high vacuum (0.1-0.2 mbar). The result~nt white, turbid viscous product is poured on to coated paper at c. 120C. After cooling, the solidified product is mechanically comminuted.
epoxy value: 2.40 equivalents/kg content of toughener: 10 phr.
216~91~
Coated Al2O3 (filler I) 1000 g of ~ minium oxide are put into a porcelain ball mill filled to about 1/3 of its volume with ceramic balls. Then 5 g of ~-glycidyloxypropyltrimethoxysilane are added and the mixture is milled for 15 h. The balls are then removed by sieving through a wide-meshed sh~king sieve. The aluminium oxide coated in this manner is used in this form in the Examples.
Example 1 With stirring, 100 g of suspension A are homogenised with 87 g of a modified methyl-hexahydrophthalic anhydride, (commercially available under the product name "XB
5996" from CIBA-GEIGY AG) in the temperature range from 50 to 60C. To this ~
are then added 560 g of filler I. The mixture is heated, with stirring, to 80C, evacuated for 7 minutes under a pressure of 3 mbar and cast in plates preheated to 100C. The gelation time of the curable epoxy resin composition is 8 min/21sec at 140C. The curable mixture has a filler content of 60% by weight, based on the total mixture. The following p~pel lies of the test samples are determined after curing for 2 h at 100C, for 10 h at 140C and for 2hat 160C:
Tg value (determined by DSC~)) = 150C
flexural strength (acc. to ISO 178) = 131 N/mm2 flexural elongation = 2.34 %
modulus of elasticity in the flexural test = 7721 N/mm2 tensile strength (according to ISO R527) = 82 N/mm2 Illtim~te elongation = 2.28 %
modulus of elasticity in the tensile test = 7392 N/mm2 double torsion test (acc. to DIN 51 221) fracture toughne~S Glc = 447 J/m2 critical stress intensity factor KlC
(fracture toughness) = 1.95 MPa~
~) Differential Scanning Calorimeter ~i6491S
`_ Example 2 100 g of suspension B, 90 g of methylhexahydrophthalic anhydride and 0.53 g of benzyldimethylamine are weighed together cold and mixed, with stirring, in the temperature range from c. 50 to 60C. To this mixture are added 391 g of filler I and the temperature is raised to 80C. The mixture is homogenised and then evacuated, with stirring, at 3 mbar for 10 min and then cast in moulds preheated to 100C. The casting composition is cured for 2 h at 100C and for 16 h at 140C. The test samples have the following properties:
Tg value (determined by DSC) = 128C
flexural strength (acc.to ISO 178) = 128 N/mm2 flexuralelongation = 1.56%
modulus of elasticity in the flexural test = 10972 N/mm2 double torsion test (acc. to DIN 51 221) fracture toughn~Ss G lC = 521 J/m2 critical stress intensity factor KlclC = 2.51 MPa~.
Example 3 100 g of suspension C are placed in a vessel at room temperature and heated to 120C. To this suspension are added 45 g of a hardener mixture con.~i~ting of 35 parts by weight of phthalic anhydride and 65 parts by weight of tetrahydrophthalic anhydride, and the entire batch is then homogenised. Into the clear solution are stirred 218 g of filler I in increments. After 15 min the mixture is degassed for 3 min at 3 mbar and then cast in moulds preheated to 100C. The casting composition is cured for 16 h at 140C. The test samples have the following properties:
Tg value (determined by DSC) = 133C
flexural strength (acc. to ISO 178) = 150 N/mm2 flexural elongation (acc. to ISO 178) = 2.79 %
modulus of elasticity in the flexural test = 8257 N/mm2 double torsion test (acc. to DIN 51 221) fracture toughness Glc = 777 J/m2 21649iS
critical stress intensity factor KlC = 2.67 MPa~.
Claims (13)
1. A curably epoxy resin casting composition, comprising a) an aromatic or cycloaliphatic epoxy resin having on average more than one 1,2-epoxy group in the molecule, b) a hardener for the epoxy resin in an amount sufficient to effect a full cure of the epoxy resin, c) a toughener, and d) a finely particulate aluminium oxide coated with a silane of formula I
R4-(n+1) ? Si ? (OR')n+1 (I), wherein R is alkyl containing 1-4 carbon atoms, a phenyl, glycidyloxypropyl, mercapto-propyl or aminopropyl group, R' is alkyl containing 1-12 carbon atoms, and n is 0 or a number from 1 to 3.
R4-(n+1) ? Si ? (OR')n+1 (I), wherein R is alkyl containing 1-4 carbon atoms, a phenyl, glycidyloxypropyl, mercapto-propyl or aminopropyl group, R' is alkyl containing 1-12 carbon atoms, and n is 0 or a number from 1 to 3.
2. An epoxy resin casting composition according to claim 1, wherein component a) is a liquid or solid aromatic or cycloaliphatic glycidyl ether or ester.
3. An epoxy resin casting composition according to claim 1, wherein component a) is a diglycidyl ether of bisphenol A or bisphenol F, or a cycloaliphatic diglycidyl ester.
4. An epoxy resin casting composition according to claim 1, wherein component b) is a polycarboxylic anhydride.
5. An epoxy resin casting composition according to claim 1, wherein component b) is an aromatic or cycloaliphatic polycarboxylic anhydride.
6. An epoxy resin casting composition according to claim 1, wherein component c) is a solid toughener.
7. An epoxy resin casting composition according to claim 6, wherein the solid toughener is a graft polymer.
8. An epoxy resin casting composition according to claim 7, wherein the graft polymer is a core/shell polymer.
9. An epoxy resin casting composition according to claim 1, wherein component c) is a toughener containing no reactive groups that could react with the respective epoxy resin.
10. An epoxy resin casting composition according to claim 1, wherein components a) and c) are together in the form of a suspension.
11. An epoxy resin casting composition according to claim 1, wherein the coatingcompound is a silane of formula I, wherein R is a methyl, ethyl, phenyl, glycidyloxypropyl, mercaptopropyl or aminopropyl group, R' is alkyl containing 1-4 carbon atoms, and n is 2.
12. An epoxy resin casting composition according to claim 1, wherein the coatingcompound is .gamma.-glycidyloxypropyltrimethoxysilane or .gamma.-mercaptopropyltrimethoxysilane.
13. An electrical or electronic component encapsulated or coated with the cured epoxy resin composition according to claim 1.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CH377594 | 1994-12-13 | ||
| CH3775/94 | 1994-12-13 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2164915A1 true CA2164915A1 (en) | 1996-06-14 |
Family
ID=4263223
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002164915A Abandoned CA2164915A1 (en) | 1994-12-13 | 1995-12-11 | Curable epoxy resin casting compositions containing core/shell tougheners |
Country Status (5)
| Country | Link |
|---|---|
| EP (1) | EP0717073B1 (en) |
| JP (1) | JPH08231827A (en) |
| CA (1) | CA2164915A1 (en) |
| DE (1) | DE59508782D1 (en) |
| ES (1) | ES2151949T3 (en) |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6632881B1 (en) * | 1999-04-13 | 2003-10-14 | Hitachi Chemical Co., Ltd. | Encapsulant of epoxy resin and liquid aromatic amine curing agent |
| US6638567B1 (en) * | 1999-03-16 | 2003-10-28 | Vantico, Inc. | Hardenable composition with a particular combination of characteristics |
| US6664318B1 (en) | 1999-12-20 | 2003-12-16 | 3M Innovative Properties Company | Encapsulant compositions with thermal shock resistance |
| US7056978B2 (en) * | 2002-11-06 | 2006-06-06 | National Starch And Chemical Investment Holding Corporation | Toughened epoxy-anhydride no-flow underfill encapsulant |
| EP1780239A1 (en) * | 2004-08-18 | 2007-05-02 | Kaneka Corporation | Epoxy resin composition for semiconductor sealing agents and epoxy resin molding material |
| US8217098B2 (en) | 2007-02-28 | 2012-07-10 | Kaneka Corporation | Thermosetting resin composition having rubbery polymer particle dispersed therein, and process for production thereof |
| US10696820B2 (en) | 2015-03-26 | 2020-06-30 | Huntsman International Llc | Thermosetting resin composition for the preparation of outdoor articles and the articles obtained therefrom |
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| ES2223963T3 (en) * | 2000-11-29 | 2005-03-01 | Huntsman Advanced Materials (Switzerland) Gmbh | EPOXI RESIN SYSTEM, PROVIDED WITH LOADS, WHICH HAS A HIGH VALUE OF MECHANICAL RESISTANCE. |
| JP4771445B2 (en) * | 2001-07-11 | 2011-09-14 | 日本化薬株式会社 | Insulating resin composition for electronic parts and adhesive sheet |
| DE502004007114D1 (en) * | 2003-09-29 | 2008-06-26 | Bosch Gmbh Robert | Hardenable reaction resin system |
| KR100689086B1 (en) * | 2005-12-30 | 2007-03-02 | 주식회사 케이씨씨 | Adiabetic panels adhesive epoxy resins for membrane type liquid natural gas tank |
| KR100914821B1 (en) * | 2007-11-28 | 2009-09-02 | 주식회사 케이씨씨 | A epoxy resin composition for semiconductor's packages |
| CN102212330A (en) * | 2010-04-07 | 2011-10-12 | 深圳市诚德来实业有限公司 | Epoxy resin adhesive for hollow fiber membrane end sealing as well as preparation and application methods thereof |
| DE102010015398A1 (en) * | 2010-04-19 | 2011-10-20 | Siemens Aktiengesellschaft | Insulating composite material for electrical insulation, method of making and using same |
| DE102010019723A1 (en) * | 2010-05-07 | 2011-11-10 | Siemens Aktiengesellschaft | Electrical insulation system for a high voltage electric rotary machine |
| WO2013139390A1 (en) * | 2012-03-21 | 2013-09-26 | Abb Research Ltd. | Curable epoxy resin composition |
| KR20180036690A (en) * | 2015-07-02 | 2018-04-09 | 훈츠만 어드밴스트 머티리얼스 라이센싱 (스위처랜드) 게엠베하 | A thermosetting epoxy resin composition for the production of outdoor articles, and articles obtained therefrom |
| JP7252212B2 (en) * | 2017-09-20 | 2023-04-04 | アランセオ・ドイチュランド・ゲーエムベーハー | Vulcanizable HNBR composition with high thermal conductivity |
| WO2022138807A1 (en) * | 2020-12-25 | 2022-06-30 | 株式会社カネカ | Curable resin composition and adhesive agent |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4529755A (en) * | 1982-10-23 | 1985-07-16 | Denki Kagaku Kogyo Kabushiki Kaisha | Epoxy resin composition for encapsulating semiconductor |
| JPS6377927A (en) * | 1986-09-19 | 1988-04-08 | Fujitsu Ltd | Molding material for semiconductor sealing |
| DE59006274D1 (en) * | 1989-04-07 | 1994-08-04 | Asea Brown Boveri | Electrical insulator. |
| JPH03237152A (en) * | 1990-02-15 | 1991-10-23 | Meidensha Corp | Cured product of alumina-filled resin |
| JPH0455463A (en) * | 1990-06-26 | 1992-02-24 | Meidensha Corp | Production of epoxy resin composition |
-
1995
- 1995-12-05 ES ES95810765T patent/ES2151949T3/en not_active Expired - Lifetime
- 1995-12-05 EP EP95810765A patent/EP0717073B1/en not_active Expired - Lifetime
- 1995-12-05 DE DE59508782T patent/DE59508782D1/en not_active Expired - Lifetime
- 1995-12-11 CA CA002164915A patent/CA2164915A1/en not_active Abandoned
- 1995-12-13 JP JP7346743A patent/JPH08231827A/en active Pending
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6638567B1 (en) * | 1999-03-16 | 2003-10-28 | Vantico, Inc. | Hardenable composition with a particular combination of characteristics |
| US6632881B1 (en) * | 1999-04-13 | 2003-10-14 | Hitachi Chemical Co., Ltd. | Encapsulant of epoxy resin and liquid aromatic amine curing agent |
| US6664318B1 (en) | 1999-12-20 | 2003-12-16 | 3M Innovative Properties Company | Encapsulant compositions with thermal shock resistance |
| US7056978B2 (en) * | 2002-11-06 | 2006-06-06 | National Starch And Chemical Investment Holding Corporation | Toughened epoxy-anhydride no-flow underfill encapsulant |
| EP1780239A1 (en) * | 2004-08-18 | 2007-05-02 | Kaneka Corporation | Epoxy resin composition for semiconductor sealing agents and epoxy resin molding material |
| EP1780239A4 (en) * | 2004-08-18 | 2011-11-16 | Kaneka Corp | Epoxy resin composition for semiconductor sealing agents and epoxy resin molding material |
| US8217098B2 (en) | 2007-02-28 | 2012-07-10 | Kaneka Corporation | Thermosetting resin composition having rubbery polymer particle dispersed therein, and process for production thereof |
| US10696820B2 (en) | 2015-03-26 | 2020-06-30 | Huntsman International Llc | Thermosetting resin composition for the preparation of outdoor articles and the articles obtained therefrom |
Also Published As
| Publication number | Publication date |
|---|---|
| EP0717073A2 (en) | 1996-06-19 |
| EP0717073A3 (en) | 1996-11-20 |
| DE59508782D1 (en) | 2000-11-16 |
| EP0717073B1 (en) | 2000-10-11 |
| JPH08231827A (en) | 1996-09-10 |
| ES2151949T3 (en) | 2001-01-16 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| FZDE | Discontinued |