CA1104146A - Dicarbonyl chelate salts - Google Patents

Abstract

Abstract of the Disclosure Cationic polymerization of epoxy monomers, or pre-polymers can be achieved by use of certain moisture sensitive dicarbonyl chelates of main row elements of Group IIIA-VA.
Curable Compositions are provided which can be used as sealants, coating compounds, glues, incapsulants, etc.

Description

~ R~-9~84 CURABI.E COMPOSITIONS

The present inven~ion relate~ to epoxy re~in composi-tion~ which can be cured by exposure to atmospheric mois~ure, based on the employment of a dicarbonyl chelate of a m~in ~ow element of Groups IIIA-VA
Epoxy resins have generally been employed in a variety of applications requiring high performance materials. Cure of an epoxy resin can generally be achieved by two package ~y tem3 ba9ed on the incorpora~ion into the resin of an ac~ive amine containing compound or carboxylic acid anhydride. These 8ystem8 requir~ thorough mixing of the ingredients; in addition, cure time can be se~eral hours.
Another catalyst which can be used to cure epoxy resins as 'lone package" ~ystems ls based on the employment of a Lewis Acid cataly~t in the form o an amine complex such as boron trifluoride-monoethyl amine. The Lewis Acid is released on heating; cure takes place within 1 to 8 hours and can require a temperature of 160~C and higher. As a result, these one package epoxy compositions cannot be employed to coat heat sensitive devices such as delicate electronic components. Nor can epoxy monomers having low boiling points be used duc to the res~lting los~e~ to evaporation durlng cure.
As 3hown by Schlesinger, Patent 3,703,296, certain photosensitive aromatic diazonium salt~ can be employed to cure epoxy resins. When p~otolyzed, the~e aromatic diazonium ~alts are capable of relea6ing, in itu, a Lewis Acid catalyst which can initiate the rapid polymerization o the epoxy resin.
However, even though these one package epoxy re~in m-ixtures can provide fast curlng composition~, a ~tabilizer mu~t be u~ed to miniml2e cure in the dark during s~orage of the~e mixtures.

~, ~ RD 9584 Despite these measures, gelation of the mixture can o~cur even in the absence of light. In addition, nitrogen is released during W-cure, which can result in film imperfec-tions. Diazonium salts are generally thermally unstable, renderin~ the use of such materials hazardous because o~
the possibility of run-away decompositon.
In U. S. Patents of James V. ~rivell, 4,058,401 issued November 15, 1977, issued , 4,069,055 issued January 17, 1978 and assigned to the same assignee as the present invention, various photodecomposable onium salts are defined which are useful for curing epoxy resins upon exposure to ultra-violet light. In my U. S. Patent 4,086,091, issued April 25, 1978 and assigned to the same assignee as the present invention, there is dislosed that certain dicarbonyl chelates of main row elements of Groups IIIA, IVA and VA
of the formula _ +Y

~ ~ n 1 L

can be used in epox~ resins to produce additional U.V.
curable compositions, where X is a main row element selected from Group IIIA, IVA and Va, J is a divalent organo radical having 3 to 42 carbon atoms, M is an element selected from Sb, As, P, B and Cl, Qlis selected from O and F, n is an integer equal to 2 or 3, y is an integer equal to 1 or 2, and a is an integer equal to 4 to 6 or the valence of M.
The present invention i~s based on the discovery that blends of epoxy resin and an effective amount of the dicarbonyl chelates can also be used under ambient conditions as sealants, RD-9S~4 coating compounds and incapsulants.
Ra~icals included by J of formula (1~ are, ~or exampl~, Rl _ and C~

. ;- R3 ,~C~, R4 _ C

where R and R~ are selected from hydrogen, amino, saturated C(1-8) aliphatic hydrocarbon, saturated C(l 8) cycloaliphatic hydrocarbon, unsaturated C(l 8) aliphatic hydrocarbon, unsat-urated C~l 8) cycloaliphatic, C(6_13) aromatict substituted C~6_13) aromatic, C(l 8) alkoxy, and halogenated derivatives thereof, etc.; R i5 selPcted from halogen, R and R2; ~, Rl and R also can be part of the same cycloaliphatic radical;
R is selected from hydrogen, amino, C(1_8) aliphatic, C(l 8) cycloaliphatic, C(6_13) aromatic, C(l_a) alkoxy and sub~tituted derivatives thereof, etc.; R4 and RS are selected from halogen, lS R2 and R3; R3 and R5, and R3, R and R can be part of a cyclo-aliphatic or aroma~ic ring, re~pectively.
Included in the carbonyl chelate~ of formula (1) are chelates, such as 'CH3~ ~o H-~ ~ Si A8F6 . ~

I ~0 \~--O ~ Sl ~33 SbF6 ~3 /
CH~ 3 CH3 ~

H C~ C ,~ B ~ C104 ~3 _~ _,. 2 4~ 6 Rn-ss8~

:- - -HJ~C j~ Si ~ A:~F6 (~

0(::2H5 ~C_~
H~ C ~Ge 33 pF6~3 ~ _ ~ ' Rn-9s~4 P ~) (sbF6(3) 2 -c~ -\~C O ~ ' P~ ~3 C104 ~) _ ¢ _ 2 CH3 ~C
L~ ~ ' ~ BF4 ~6--~ ~ 4 ~ ~ ~ RD-9584 There is provided by the Present invention, moisture curable epoxy com~ositions compri~ing, (A) an ePoxy re~in ~olymerizable ~o a high molecular weight state selected from epoxy monomer, ePoxy prepolymer, oxirane containing organic polymer and mlxtures thereof and (B) an efective amount of a moisture sen6itive dicarbonyl chelate of form~la (1).
The dicarbonyl chelates of formula (1) can be pre-parPd by a me~athetical reaction be~tween an alkali metal salt of an MQa acid with the halide salt o a chelate Prepared by ~e direct reaction of a dicarb~nyl ligand with a halide of an ~p~ropriate X in the ~resence of an organic solvent under anhydrous conditions hy procedures shown by R. West, J. Amer.
Chem. Soc., 80, 3246 (1958), E. L. Muetterties and A. N. Wright, J. Amer. Chem. Soc., 86, 5132 (1964), R. Riley, R. West and R.
__ Barbarian, Inorg. Syn., 1, 30 (1963), W. Dilthey, Ann. 344, 300 (1906) and R. We~t, J. Org. Chem., 23, 1.552 (1~58).
The term "epoxy resin" as utiliæed in the descri~tion of the curable com~ositionq of the present invention, includes any monomeric, dimeric or oligomeric or ~olymeric ~oxy material containing one or a plurality of ePoxy functional group~. For example, those resins whi~h result from the reaction of bi~phenol-A (4,4'-isopropylidenediphenol) and epichlorohydrin, or by the reaction of low molecular weight phenol-formaldehyde resin~ (Novolak resins) wi~h epichlorohydrin, can be u~ed alone or in combination with an epoxy containing compound as a reactive diluent. Such diluentg as phenyl glycidyl ether, 4-vinylcyclohexene dioxide, limonene dloxide, 1,2-cyclohexene oxide, glycidyl acrylate, glycidyl methacrylate, styrene cxide, RJ)-~rB4 allyl glycidyl ether, etc., may be added a~ vi~3c03ity modi~yirlg agent s .
In addition, the range of these compounds can be extended to include polymeric materials containing terminal or pendant epoxy groups. E~amples of ~hese compounds are vinyl copolymers con~aining glycidyl acryla~e or me~hacrylate as one of the comonomers. Oth~r clas6es of epoxy containing polymers amenable to cure using the above catlysts are epoxy-siloxane re~ins, epo~y-polyurethane~ and epoxy-polyesters.
Such polymers usually have epoxy functional groups at the ends o their chains. Epoxy-siloxane resins and method for making are more particularly shown by E.P. Plueddemann and G. Fanger, J. Am. Chem. Soc. 81 632-5 (1959). As described in the literature, epo~y resins can also be modified in a number of standard ways such as reactions with amines, car-boxylic acids, thiols, phçnols, alcohols, etc., as sho~ in patent 2,935,488; 3,235,620; 3,369,n55; 3,379,653; 3,398,211;
3,403,199; 3,563,850; 3,567,797; 3,677,995, etc. Further examples of epoxy resins which can be uset are shown in the Encyclopedla of Polymer Science and Technology, VQ1. 6, 1967, Interscience Publishers, New York, pp 209-271.
The curable compositions of the present invention can be made by blending the epoxy resin as Previously defined with an effective amount of the dicarbonyl chelate. The re~ulting curable composition can be in the ~orm of a varni~h havin~ a viscosity of from 1 centipoise to 100,000 centi~oi~e~ a~
25C or a free flowing powder.
Depending upon the compatabili.ty o~ the dlcarbonyl chela~e with the epoxy resin, the chelate can be dissolved or dispersed therein along with an or~anic solvent ~uch a~

~~ _ 4 ~ ~

nltromethane, a~etonitrile, etc., prior to its incor~oratlon.
In in~tances where the epoxy resin i9 a solld, incor~oratlon of the chelate can be achieved by dry milling or by melt mixing the resin whereby the chelate is incorporated.
Experlence has ~hown that the proportion of dicarbonyl chelate to epoxy resin c~n vary widely lnasmuch as the chQlata i~ substantially inert, un~less activated with moiskure. Ef~ec-tive results can be achieved if a proPortion of from .1% to lS~/~ by weight of the chelate i~ emrloyed, based on the weight o curable com~osition.
The curable composition~ also may contain inactive ingredients such as inorganic fillers, dyeA~, pigments, extenders, visco~ity control agents, process aid~, UV-screens, etc., in amount~ of Up to 100 part~ of filler per 100 parts o~ epoxy resin. The curable compositions can be applied to 3uch sub-strates as metal, rubber, plastic, molded parts or films, paper, wood, gla~s cloth, concrete, ceramic, etc.
Some of the applications in which the curable com-positions of the present invention ean be u~ed are, for example, protective, decorative and insulating coating~, pottin~ com-pounds, printing inks, sealant~, adhesives, photoresi~t~, wire insulation, textile coatings, laminates, impregnated ta~e~, prlnting plates, etc.
In order that those skilled in ~he art will be better abl~ to practice the invention, the following examples are given by way of illustration and not by way of limitation.
All part~ are by weight.
Example 1.
A solution of 1~ ml of acetyl acetone and 20.5 ml of silicon tetrachloride ln 80 ml of dry benzene was refluxed ~ 4 ~ RD~9584 or one hour. The cooled mlxture wa8 11tered and the col-lected product was drled 15 hours in a vacuum de~lccator. The dried material had a melting point of 174-176 d2grees centri-grade and weighed 20.6 ~rams. Based on method of prepa~ation and 29Si NMR spectralthe product wa3 ~ri~-acetyl acetonato silicon~IV~ chloride hydrochloride.
A ~olution of one gram of the above tris-acetyl acetonato silicon(IV~ chloride hydrochloride in 5 ml of methyl-ene chloride was mixed wi~h 0.5 grams of 30dium hexafluoro~
phosphate and S ml of a mixture of methylene chloride and scetone. The mixture was heated on a s~eam bath until evolu-tion of hydrogen chlorlde was completed. The cooled solution was diluted with ether and the precipitate product was col-lected by filtration. There was obtained I.0 gram of solids which were redissolved in methylene chloride, filtered and reprecipitated with ether. There was ob~ained 0.6 gram of the corresponding hexafluorophospha~e ehelate having a melt-ing point of 136-140C and the formula, Si 0 PF6 The identity of the salt was further confirmed bY
its infrared, H-NMR and 29Si NMR Spectra.
A curahle composition was prepared by dissolving 0.1 gram o the a~ove hexafluorophosphate silicon chelate into 5 grams o epoxy resin of the formula, \

along with enough acetone to make ~ homogeneous ~olu~ion. The curable compo~ition was t~en a~plied onto a gl~ss substrate to a thickness of about 10 mil. The treated glass sub trate was then exposed to steam at a ~em~erature of about 95C. A
tack-~ree film was obt~ined in le~s than 2 minutes.
Example 2.
In accordance with the procedure of Example 1, 2%
Qolutions of several addi~ional chelates and the epoxy resin of Example 1, were prepared. For example, tris-acetyl-l acetonato silicon (IV) hexafluoroantimonate was prepared by effecting reaction between 1 part o tris-acetylacetonato silicon (IV~ hydrochloride with 0.8 Part of sodium hexafluoro-antlmonate in about 5 parts of acetone. Sodium chloride was removed by filtration1 followed by treatme~t of the filtrate with dry ether to produce 0.6 part of tris~acetylacetonato sillcon (IY) hexafluoroantimon~te. The various moisture curable epoxy resln co~positions were exposed to steam at 95C under sealed conditions. The following results were obtalned where "chelate salt" indicates the particular tris-acetylacetonato silicon (IV) chelate salt employed in the mixture and "cure time" lndicate~ the period o exposure to steam at 95~C in minutes:
Chelate Salt Cure Time ~Min.) SbF6 AsF6 1.5 BF~ Slight tackines_ ', a~ter 15 min.

` ` ~

4~ 46 RD g s 8 4 In addi~ion to the above shown chelate salts utilized in the practlce of the invention, a 2% solution of tri~-acetyl-acetonato silicon (IV) ~IC12 was also evaluated. It was ound that the resulting epoxy mix~ure did not cure a~ter 15 minutes exposure to steam.
Example_3.
Reaction was effec~ed between 2 grams of ~cetyl-acetone and 5 ml of methylene chloride with lO ml of a 0.2 molar solution of boron trichloride. When gas evolutlon ceased, t~e solution was diluted with 50 ml of e~her and ~he chloride salt was isolated. The corresponding boronium hexafluoroanti-monate salt was prepared by mixing the aforementioned methylene chloride salt solution with 1.5 grams of sodium hexafluoro-antimonate dissolved in acetone. The sodium chloride which wa~ formed was removed by fil~ration and the desired dicarbonyl boronlum hexafluoroantimonate salt was lsolated by dilution of t~le filtrate with ether, ~ollowed ~y filtration.
A curable composition was prepared by dissolving 3.2 grams o the above chelate and 10 grams of the epoxy resin of Example l. A 25 mil film of the resulting compo~itlon WRS exposed to air at a 50% relative humidity. A tack free gel was formed after 1 hour of exposure and a solid cured film was obtained after 6 hours of exposure.
Exam`~
. .
A solution o 9,8 grams of dibenzoyl methane and 5.1 ml of silicon tetrachlorlde and 40 ml of dry benzene was refluxed for 30 minutes. The precipitated salt was collected by iltration. A solution of 1.5 grams of the crude 3alt in chloroform and equal volumes of chloroform and ace~one wa~
mixed with 0.5 gram~ of sodium hexafluoroantimonate in acetone.

.,, -12- ~

. ..
', A~ter removal of 90~iUm chloride by filtration and precipitatio o the resultlng chela~e from the iltrate w~th ether there waa obtalned 1.3 grams of tris-dibenzoyl methanato silicon (IV) .
hexafluoroantimonate as yellow prisms. It8 melting point w~s 270~271.5C.
A curable composition wa3 prepared by dissolving 0.1 gram of the above chela~e and 2 ml of acetone and then adding 5 grams of ~he the ep~xy resin of Example 1. ~xpQsure of the resultlng eomposition to gteam ~or 2.5 minutes produced a solid brittle ma~s. In the absence of moi~ture, the 801u-tion remained fluid for a~ least two month~ at ambient temper-ature.
Example 5.
A tris-tropolonate dichloride chelate of phosphorus lS was prepared by mixing a solution of 8.4 grams of phosphorus pentachloride .in methylene chloride with a solution of 1.5 grams of tropolone in methylene chloride. There was reacted 0.5 grams of the aforementioned chelate with two equivalents of ~odium hexa~luoroantim~nate to yield the corresponding bis-hexafluoroantimonate chelate.
A curable compDsition was prepared from O.OS part o~
the above chelate and S parts of the epoxy resin o Example 1.
along with sufficient acet~ne to produce a homogeneous solution.
~xposure of the solution to a 75% RH atmosphere produced a ,~
hard gel after about 3-4 hour~
Example 6-16. ' . :
Addltlonal dicarbonyl chelates were prepared ollowing ~
the procedure pre~iou~ly de~cribe~. The dicarbonyl chelate~
were re3pectively mi~ed with the diepoxide of Example 1 to ,.
produce curable mixture~ having about 1% by weight of the di- ;., -13~ ~j '.~j i'~

~4146 RD 9584 carbonyl chelate. The following table shows the dicarbonyl chelates which were prepared where "J", "X" and "~Qa" are defined in formula (1):
TABLE I
J X MQa l-penyl-1,3-butenyl Si SbF6 l-ethylcyclohex-l-en-2-yl Si SbF6 1,2-cyclohepta-2,4,6-trienyl Ge SbF6 l-ethyl-cyclopent-l-en-2-yl Si SbF6 1,3-diphenylpropenyl B SbF6 5-ethoxy-2,4-pent-2-enyl Si SbF6

2,4-pent-2-enyl Si ~ C104 1,2-cyclohepta 2,4,6-trienyl Si SbF6 l-ethylcyclopent-1-2-yl Si C104 1,3-diphenylpropenyl Ge SbF6

3-chloro-2,4-pent-2-enyl Si SbF6 The above compositions were found to cure to a hard gel af~er being applied to a thickness of about 1 mil on a steel substrate and exposed to steam at atmos-pheric pressure for 10 minutes.
Example 17.
A pol~merizable composition was prepared by dissolving 2 parts of tris-acetylacetonatosilicon (IV) hexa-fluoroantiamonate in part dry chloroform and 100 parts of Epon 828, which is a digylcidylether of bisphenol-A. This mixture was appIied to fiberglass tape wound around a copper conductor. When this tape-wrapped conductor was exposed to steam, the epoxy resin set to a hard coating after 10 minutes of exposure.
Examples 18-27 Further dicarbonyl chelates were prepaxed in accordance with the previously described procedure.
These dicarbonyl chelates included by the formula, (2) ~ [J \ \/ l X I+ LM~6~ - , are shown in Table II below, where J is a divalent organo radical having 3 to 42 carbon atoms, X is a main row element selected from Group IIIa, IVa and Va, M
is an element selected from B, As, and P, and n is an integer equal to 2 or 3.

. .

o l ~ ~i .~ ~ ~ ~1 ~1 ~1 U~ ~
N

a) ~ ru c~ ~ ~ o ~ o ~
r-l OCO a~ oco N
N t~ 0 IS~ ~1 ~) ~C~ l I
oo Oo ~ ~)~D ~ Na~ I I
r~ ~ ~ ~ Nr~ I
~J
~ U~
O ~ N
O
h ~4 hli ~D h 1:4 Q F4 h 1~ ¢~
t~ ~; Q u~ ~ QU~ ~.Q m u~
o o u~
H u~
H Q) U~
~) ~ N ~ t~~) ~) ~:1 ~J ~1 5~ 0 ~ a) E~ 0~ ~ rl rl ~rl rl ~1 ~rl rl ~ ~1 rl ~ ~
i~n P~ ~ ~ ~(V iV
il) ~9 l o o N~1 ~I N
~11 ~ IQ~ Ql I
N N
r~l~1 ~-1 I ~ I iD O O
~1 au iD ~ iVp, ~riV iV
I i I iD Ia) ` I
N N N ,~, N,~, N~) ~1 ~1 I I I O I O I ~ I I
.IJ~) ~ ~ ~~1 ~1~1 ~1 0 a~ ~ iV ~ a) ~ o ~ ~ ~ N ~ N
N N N ~ N r-l i~ ~1 ~I rf) X ~ ~ O r-l N ~) ~ i-O ~D i~
h ~1 ~I N N N N N N N N

~ RD 9584 Curable mixtures are made by blending 1% by weight of the above dicarbonyl chelates with the diepoxide of Example l. These compositions are found to cure to a hard gel after being applied to a thickness of about l mil on a steel substrate and exposed to steam at atmospheric pressure for about 2 minutes.
Although the above examples are directed to only a few of the very many variables included by the curable compositions of the present invention, it should be understood that the curable compositions include a much broader variety of dicarbonyl chelates of formula (l) and the epoxy resin compositions shown in the descrip-tion preceding these examples.

Claims (25)

The embodiments of the invention in which an exclu-sive property or privilege is claimed are defined as follows:

1. A moisture curable epoxy composition comprising (A) an epoxy resin polymerizable to the high molecular weight state selected from epoxy monomer, epoxy prepolymer, oxirane containing organic polymer and mixtures thereof, and (B) an effective amount of a moisture sensitive dicarbonyl chelate of the formula, , where X is a main row element selected from Group IIIA, IVA and VA, J is a divalent organo radical having from 3 to 42 carbon atoms, M is an element selected from Sb, As, P and B, and Cl, Q is fluorine or oxygen, n is an integer equal to 2 or 3, y is an integer equal to 1 or 2, and a is an integer equal to 4 to 6 or the valence of M.

2. A curable composition in accordance with claim 1, where X of the dicarbonyl chelate is silicon.

3. A curable composition in accordance with claim 1, where X of the dicarbonyl chelate is boron.

4. A curable composition in accordance with claim 1, where X of the dicarbonyl chelate is phosphorous.

5. A curable composition in accordance with claim 1, where X of the dicarbonyl chelate is germanium.

6. A curable composition in accordance with claim 1, where the dicarbonyl chelate is tris-acetyl acetonato silicon (IV) hexafluorophosphate.

7. A curable composition in accordance with claim 1, where the dicarbonyl chelate is tris-acetyl acetonato silicon (IV) hexafluoroantimonate.

8. A curable composition in accordance with claim 1, where the dicarbonyl chelate is tris-acetyl-acetonato silicon (IV) hexafluoroarsenate.

9. A curable composition in accordance with claim 1, where the dicarbonyl chelate is tris-acetyl-acetonato silicon (IV) tetrafluoroborate.

10. A curable composition in accordance with claim 1, where the dicarbonyl chelate is tris-acetyl-acetonato silicon (IV) perchlorate.

11. A curable composition in accordance with claim 1, where the dicarbonyl chelate is tris-tropolonato silicon (IV) hexafluoroantimonate.

12. A curable composition in accordance with claim 1, where the dicarbonyl chelate is tris-dibenzoyl-methanato silicon (IV) hexafluoroantimonate.

13. A curable composition in accordance with claim 1, where the dicarbonyl chelate is tris-2-acetylcyclo-hexanato silicon (IV) hexafluoroantimonate.

14. A curable composition in accordance with claim 1 where the dicarbonyl chelate is tris-2-acetyl-cyclopentanato silicon (IV) hexafluoroantimonate.

15. A curable composition in accordance with claim 1, where the dicarbonyl chelate is tris-ethyl-benzooylacetato silicon (IV) hexafluoroantimonate.

16. A substrate coated with the cured composition of claim 1.

17. Dicarbonyl chelates having the formula, , where J is a divalent organo radical having 3 to 42 carbon atoms, X is a main row element selected from Group IIIa, IVa, and Va, M is an element selected from B, As and P, and n is an integer equal to 2 or 3,

18. A dicarbonyl chelate having the formula, in accordance with claim 17.

19. The compound tris-acetylacetonatosilicon (IV) hexafluoroantimonate in accordance with claim 17.

20. The compound tri-acetylacetonatosilicon (IV) hexafluoroarsenate in accordance with claim 17.

21. The compound bis-acetylacetonatoboron III hexafluoroantimonate in accordance with claim 17.

22. The compound tris-dibenzoylmethanatosilicon (IV) hexafluoroantimonate in accordance with claim 17.

23. The compound tris-dibenzoylmethanatosilicon (IV) hexafluoroarsenate in accordance with claim 17.

24. The compound tris-3-chloroacetylaceton-atosilicon (IV) hexafluoroantimonate in accordance with claim 17.

25. The compound tris-3 chloroacetylacetonato-silicon (IV) hexafluoroarsenate in accordance with claim 17.