CA1146560A - Silanes containing imide groups - Google Patents

Abstract

Abstract The compounds according to the invention have the formula I

Description

- ~465~0 3-12001/ZFO/+/B

Silanes containing imide groups . _ . . .

The present invention relates to novel silanes containing imide groups and their use as adhesion promoters, for example between inorganic solids and organic resins.

It is known from the literature that diverse silanes, such as vinyl-trichlorosilane, vinyl-tris-(2-methoxy-ethoxy)-silane, y-aminopropyl-triethoxysilane and [N-(2-aminoethyl)-3-aminopropyl]-trimethoxy-silane, can be used as adhesion promoters for diverse applications, for example for the preparation of glass fibre-reinforced plastics, especially laminate sheets for electrical applications, and for sealing compositions, lacquers and adhesives [compare, for example, Defa~et, 28, 207-211 (1974) and Kunststoffe, 55, 909-912 (1965), U.S. Patents 2,901,913 and 3,755,354 and German Offenlegungsschrift

2,504,791].
., ! However, the properties of the products obtained with these known adhesion promoters leave something to be desired in some respects.
The products are to be regarded as very unfavourable especially in respect of one or more of the following 3 properties: absorption of ., water, thermo-oxidative stability and dielectric characteristics.
.: ' The object of the invention was, therefore, to provide novel adhesion promoters with which the above disadvantages can be overcome.

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The i.nvention relates ~o compounds of the formula I

y/ ~ - A - Si - Rl (I) in which R and R independently of one another are methyl, ethyl, phenyl, vinyl, chlorine or a group -OR, R is chlorine or -OR, R is : alkyl having 1-10 C atoms, cycloalkyl having 5-8 C atoms or phenyl, A is one of the divalent radicals -(CH2) -, -C(R )2-CH-C(R )-, -C(R )2-CH(R )-, -(CH2)b-G-(CH2) -, phenylene-(CH2)d-G-(CH2)c-, phenylene-(CH2)d-, C(R10) -CH(Rll)- or co , .
CO
~\ ~ N phenylene-(CH2)d-M-(CH2)c-and in these divalent radicals A the bond to the Si atom is in each case effected via the bond on the right-hand side, R is hydrogen, .. , methyl or ethyl, R is hydrogen or alkyl having 1 to 10 C atoms, a is a number from 1 to 10, b and c independently of one another are a number from 1 to 6, d is a number from O to 6, G is -CH(R )-, -NH-, -N(R )-, -O~ or phenylene and M is -O-, -NH- or -N(R )-, and in which Y is Rl 2 ~
r ~ ~ or R8 li 13/-\ ~ \

65~

R is hydrogen, methyl, phenyl, -CN or halogen, R is methyl, phenyl, -CN or halogen and R is alkylene having 3 or 4 C atoms, which can be branched and can be interrupted by an O-atom, or is one of the radicals . _ . _ . ~ _ _ =-\ ./ ' ~ ! or I ! ' \./ \./ ,, with the proviso that A cannot be ~ O-(CH ) -or ~ --O-(CH ) ~
~, ~/ \CO =-if R and R are each methyl.

Diverse processes can be used for the preparation of the silicon compounds according to the invention.

The first process (A) comprises reacting a compound of the formula II

Q CO (II) Ql -CO
!~
in which Y is as defined under formula I and in which Ql is -OH, chlorine, alkoxy having 1-6 C atoms or phenoxy and Q2 is alkoxy having 1-6 C atoms or phenoxy, or Ql and Q2' in pairs, form the grouping -O-, with a compound of the formula III

~ ~165~

H2N - A - Si - R (III) R3' in which A is as defined under formula I and in which R , R and R have the meanings defined for R , R and R under formula I but cannot be chlorine, in approximately stoichiometric amounts, if desired with a slight excess of the silane of the formula III, and if desired in the presence of an organic solvent, to give the amido-carboxylic acid of the formula IV

R2~
R - Si - A - NH CO (IV) R Q CO

in which Q is -OH, alkoxy having 1-6 C atoms or phenoxy, and cyclising the amidocarboxylic acid of the formula IV, which is thus obtained, in a known manner, if desired in the presence of an inert organic solvent, to a compound of the formula I and, if desired, in this compound replacing one or more - OR groups by chlorine in a known manner. The amidocarboxylic acids of the formula IV can also be appl;ed direct to the substrate and cyclised on the substrate.

Virtually all of the compounds of the formula I can be prepared by this process (A). Solvents which can be used are, for example, N,N-dimethylformamide, N,N-dimethylacetamide, benzene, toluene, xylene, dioxan or n-hexane.
., A further process (B) for the preparation of the products according to the invention is l;mited to the preparation of those compounds of the formula I in which A is one of the divalent radicals ,~

, 1~ ~65~

\CH - ~ - E3_, E6 _ ~ - CH - E3-- E5--C = CH - E3--or E - CH = C - E3-preferably 6 E¢ ,E 3 or E ~ C = CH - E3-which in each case are bonded via E to the N atom and in which E
is a direct bond, alkylene having 1 to 8 C atoms, cyclohexylene, phenylene or -CH2-phenylene, which is bonded via the -CH2 group to the N atom, and E and E independently of one another are hydrogen, methyl or ethyl and E is hydrogen or alkyl having 1 to 9 C atoms.
This process comprises reacting a compound of the formula V

6~C = C - E - N\ ~Y (V) or a compound of the formula VI

E5 - C - C - E3 - N/ ~Y (VI ) CO
in the presence of a noble metal or of a noble metal compound or in the presence of an organic peroxide or, alternatively, under UV
radi.ation and if desired in the presence of an inert organic solvent, with a silane of the formula R
H - Si - R

1~ 46S~Q

in which R , R and R are as defined under formula I, in a molar ratio of about 1:2.

Solvents which can be employed for this process are, for example, toluene, benzene, xylene or dioxan.

Suitable noble metal catalysts are the known catalysts, for example platinum black or palladium black, colloidal platinum, or palladium or rhodium on a support material, such as active charcoal or kiesel-guhr. Suitable noble metal compounds are inorganic salts, for example halides, and complexes, for example those with phosphines.
H2PtC16 is preferably used.

Organic peroxides suitable as catalysts are, for example, dibenzoyl peroxide, dilauroyl peroxide, methyl ethyl ketone peroxide, cumene hydroperoxide and tert.-butyl hydroperoxide.

Finally, a further process (C), with which it is possible to prepare products according to the invention, must also be listed. This process comprises subjecting an alkali metal compound, preferably the Na or K compound ; ~
CO
Me - N\ ~ (VII) CO
in which Me is the alkali metal, to a condensation reaction with a silane of the formula VIII
R2~

L - A - Si - R ' (VIII) R3' in which L is halogen, preferably chlorine or bromine, and in which R ', R ', and R ', have the meanings defined for R , R and R in ~4~

formula I but cannot be chlorine, in approximately stoichiometric amounts, if desired with a slight excess of the silane of the formula VIII, and if desired in the presence of an inert organic solvent, preferably at temperatures between 25C and 150C, and, if desired, replacing one or more -OR groups located on the siIicon atom by chlorine in a known manner.

Solvents which can be employed for this process are, for example, N,N-dimethylformamide, N,N-dimethylacetamide, methanol or ethancl.

If products of the formula I in which all or some of R , R and R
are chlorine are obtained by one of the process A) to C), chlorine can also be replaced by a radical - OR by known methods in a secondary reaction.
:;
The starting materials for the processes of prepara-tion (A-C) are known and can be prepared by known methods. For example the alkali metal compounds of the formula VII are described in German Offen-legungsschrift 2,626,795.

The silanes of the for~lula I are particularly suitable as adhesion promoters and are superior to the known adhesion promoters mentioned initially. The invention therefore also relates to the use of the silanes of the formula I as adhesion promoters.

The silanes of the formula I can also be used as starting materials for a photochemical process (D) for the preparation of compounds of the formula IX or of reaction mixtures containing compounds of the formula IX

1~4656~

1 li A ~ ~ / \N - A Si Rl (IX) in which the two rings which each contain a N atom and the radical Z
are 5-membered or 6-membered rings and in which Z can be a straight-chain or branched tetravalent aliphatic radical having 2-8 C atoms, which can be interrupted by one or more N-atoms, or a tetravalent cycloaliphatic radical of the formula R4 R5 R4. R5 R8/ , , i~

-CH2 - i 1 or -./ ~ .

in which R , R , R and R independently of one another are hydrogen,methyl, phenyl, -CN or halogen, R is alkylene having 3 or 4 C atoms, which can be branched and can be interrupted by an -O-atom, or are one of the radicals \.-./ l\ /! or .\./!

and X is -CH - or -O- and in which R , R , R and A are as defined under formula I.

~1465~0 Reaction mixtures of this type are obtained by irradiating a compound of the formula I in an organic solvent and if desired in the presence of a sensitiser and/or benzene, at temperatures between 5C and 120C
with UV light.

Organic solvents which can be used for this process are, for example, dioxan or acetone. Suitable sensitisers are, for example, thio-xanthones, which can be halogenated, benzophenone and acetophenone.

In general, the reaction mixtures contain in particular dimers and oligomers, and can also contain monomers of the formula I. In principle, however, they can by all means also contain yet further by-products.

The silanes of the formula I, according to the invention, and also the products obtained by photoreaction of compounds of the formula I
are valuable adhesion promoters, especially between inorganic solids and organic resins, and are suitable for a large number of appli-cations ;n the adhesives industry and in the lacquer-processing and plastics-processing industry.

Examples of some fields of application are: for improving the adhesion of specific sealing compositions, for example polysulfides, polyurethanes and polyacrylates, on diverse substrates, such as glass, aluminium and ceramics; for coating mineral fillers in order to improve the mechanical properties of the products produced there-with, for example in the case of the sand-filled shells and cores used in the foundry industry, mineral-filled cable mixtures or other mineral-filled plastics, for example filled thermosetting plastics, such as quartz-filled epoxide resins and filled unsaturated poly-esters, filled thermoplastics, such as polyamide 6,6 and poly-ethylene terephthalate, and filled elastomers, such as natural and synthetic rubber; and for adhesives, adhesive compositions and .

1~465~C~

epoxide, polyacrylate, polyurethane and vinyl chloride copolymer lacquers. The said compounds are, however, in particular suitable for the preparation of reinforced plastics, especially glass fibre-reinforced plastics, espec;ally composite materials, such as laminates for electrical applications, in order to improve the adhesion between the substrate or the matrix and the plastic applied thereto. The substrate can be in any form per se, for example in the form of fibres, fabrics or nonwovens, and preferably consists of glass or, alternatively, of mineral substances, such as quartz, rock wool, asbestos, mica or metallic fibres and foils. Suitable plastics for the preparation of such laminates are, for example, acrylates and polyester, epoxide, silicone, melamine, phenol and furan resins;
and also polyamides and polyamide-acids or polyimides, but especially polymers which are crosslinkable via C=C double bonds, such as unsaturated polyesters and homo- and copolymers which contain maleimidyl or nadicimidyl groups, their precursors or mixtures with other polymers.

Compared with silicon-containing adhesion promoters previously known, the adhesion promoters according to the invention are distinguished, in particular, by a lower volatility and by an increased stability to high temperatures, better stability to boiling water and good dielectric properties of the products prepared therewith. Moreover, the adhesion promoters according to the invention are readily soluble in organic solvents, have low sensitivity to hydrolysis and are stable on storage.

The invention is described in more detail and illustrated in the following examples.

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. 46S~C~

Preparation of starting materials Examp]e a CH3\ ~

~ _ CH2 - CH = CH2 A solution of 57 g (1 mol) of allylamine in 200 ml of toluene is added dropwise to a mixture of 126 g (1 mol) of 2,3-dimethylmaleic anhydride and 500 ml of toluene, with stirring. After the exothermic reaction has subsided, the mixture is refluxed under a water separator until the calculated amount of water has been separated off.
The reaction solution is dried over magnesium sulfate and filtered and the filtrate is freed from the solvent in vacuo. The residual oil is distilled under a high vacuum. Boiling point 125-130C/2666.6 Pa; yield 154.2 g = 93.5% of theory.

This product is employed in Example 2 (as described below).

Example b 126 g (1 mol) of 2,3-dimethylmaleic anhydride and 61 g (1 mol) of ethanolamine are reacted by heating at 180C for 1 hour to give 150 g of N-(2-hydroxyethyl)-2,3-dimethylmaleimide (boiling point 110C
under 13.33 Pa; yield 89% of theory). After drying, the N-(2-hydroxyethyl)-2,3-dimethylmaleimide is mixed with 181.5 g (1.78 mols) of acetic anhydride and 3 drops of concentrated sulfuric acid and the mixture is refluxed for one hour in an oil bath heated to 160C.
The acetic acid formed and the acetic anhydride are then distilled off in vacuo. Fractionation of the residue under a high vacuum yields 179 g of N-(2-acetoxyethyl)-2,3-dimethylmaleimide (boiling point 104C/6.66 Pa; yield 95% of theory). The N-(2-acetoxyethyl)-2,3-dimethylmaleimide is introduced dropwise, under nitrogen, in the course of 75 minutes into a glass column which is filled with 1~ ~65~i~

~ 12 -Raschig rings and is heated to 550C. The pyrolysis products are collected at the lower end of the glass column in a cooled receiver.
The yellow oil obtained is taken up in diethyl ether and treated with aqueous sodium bicarbonate solution in order to remove the acetic -acid. After drying the organic phase over sodium sulfate, the solvent is removed in vacuo and the product is distilled under a high vacuum.
In addition to 39.3 g of unconverted starting material, 84.7 g of (N-vinyl)-2,3-dimethylmaleimide are obtained in the form of a yellowish oil; boiling point 58-60C/53.33 Pa; yield: 85% of theory, based on converted starting material.

This product is employed according to Example 5 (as described below).

Example c CH3\ ~CO ._.
Ii ~ ~ CH2 ~-~ /.-CH CH2 CH / \C0 =-38.1 g (0.25 mol) of 4-chloromethyl-styrene are addes slowly dropwise to a suspension of 29.4 g (0.2 mol) of sodium 2,3-dimethylmaleimide [prepared from 2,3-dimethylmaleimide and sodium methylate] in 100 ml of dry N,N-dimethylformamide. After the exothermic reaction has subsided, the reaction mixture is stirred for 1 hour at 60C and, after cooling, 500 ml of distilled water are added. The aqueous mixture is extracted with 200 ml of diethyl ether and after drying the organic phase over sodium sulfate the diethyl ether is distilled off. The resulting yellow, viscous oil is freed from solvent residues at 50C/0.133 Pa. Yield 27.4 g (= 57% of theory). Analysis for calculated C 74.67% H 6.27% N 5.81%
found C 74.6% H 6.5%N 5.8%.

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- ~ :

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This product is used as the starting material according to Example 9.
.

Preparation of produ _s of the formula I
All of the reactions are carried out in stirred vessels made of glass, which are fitted with a reflex condenser, an internal thermometer, a dropping funne,ll with a pressure-equalisation device and a stirrer.

The reactions are carried out with the exclusion of atmospheric humidity. All of the reactions with H-Si compounds and the photo-reactions are carried out in an atmosphere of dry nitrogen.

The structure and the composition of the products are confirmed by IR, NMR and mass spectroscopy and by elementary analysis.

'rhe molecular weights are determined with the aid of a vapour pressureosmometer.

Example 1 (Process A) CH3\ ~CO OIC2H5 I! ~ - (CH2)3 ~ Si ~ C2H5 A mixture of 21.8 g (0.173 mol) of 2,3-dimethylmaleic anhydride, 38.3 g (0.173 mol) of 3-aminopropyl-triethoxysilane, 500 ml of n-hexane and 0.5 g of pyridine is refluxed under a water separator until the calculated amount of water has distilled over. The reaction mixture is then cooled and the supernatant hexane solution is decanted off from the higher molecular weight products, which have precipitated out. After removing the solvent, 3-(2,3-dimethyl-maleimido)-propyl-triethoxysilane is distilled under a high vacuum;
boiling point 122C (0.133 Pa); yield 30 g = 54% of theory.

1~ ~65~C~

Example 2 (Process B) 24.8 g (0.15 mol) of N-allyl-2,3-dimethylmaleimide and 0.5 ml of a 0.02 molar solution of hexachloroplatinic acid in diethylene glycol dimethyl ether are heated to 120C under nitrogen. At this tempera-ture, a mixture of 39.9 g (0.165 mol) of dicyclohexyloxy-methylsilane and 0.5 ml of a 0.02 molar solution of H2PtC16 in diethylene glycol dimethyl ether are slowly added dropwise at such a rate that the reaction temperature remains within the range of 120-130C. After the dropwise addition is complete, a further 0.5 ml of catalyst solution is added and the reaction mixture is heated at 140C for one hour. The product [3-(2,3-dimethylmaleimido)-propyl-dicyclohexyl-oxy-methylsilane] is then distilled under a high vacuum; boiling point 154-160C (0.133 Pa); yield 39.2 g = 64% of theory.

Example 3 (Process C) A mixture of 16.3 g (0.1 mol) of potassium 2,3-dimethylmaleimide (prepared by reacting 2,3-dimethylmaleimide with potassium methylate in methanol) and 150 ml of dry N,N-dimethylformamide is heated to 70C. At this temperature, 19.8 g (0.1 mol) of 3-chloropropyl-trimethoxysilane are added dropwise. After the exothermic reaction has subsided, the reaction mixture is kept at 70C for a further 2 hours, and after cooling to room temperature (20-25C) the salt which has precipitated is filtered off. The N,N-dimethylformamide is distilled off under a high vacuum, under 13.333 Pa. The residue is taken up in a little dry diethyl ether, filtered again and, after removing the solvent, fractionated under a high vacuum. 16 g (56%
of theory) of 3-(2,3-dimethylmaleimido)-propyl-trimethoxysilane are obtained; boiling point 112C (0.133 Pa).

Examples 4-14 Further compounds of the formula I were prepared according to processes A and B. The starting materials are listed in Table I and the particular process used is quoated. Examples 1 to 3 have also been included in the table.

-

3~ 65~Y

Products of the formula I which contain Rl 2\1i/

R13/ \

as Y and also products of the formula I which contain R 1l ~ -\

as Y are obtained according to Examples 4 to 10. The products are characterised in Table II with the aid of their molecule groups for formula I. Additional Examples 11-15 are also listed in this table.

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Table I
Ex- Silane of the formula Monofunctional Process ofample 2 compound analogous preparation No. H~i-R to formula V
. or R3 or Silane of the formula III Monofunctional com-pound analogous to formula II
or or Silane of the formula VIII Monofunctional alkali metal compound analo-gous to formula VII
1 3-aminopropyl-triethoxy- 2,3-dimethylmaleic A
silane anhydride 2 dicyclohexyloxy- N-allyl-2,3-dimethyl- B
methylsilane maleimide*
3 3-chloropropyl-trimethoxy- potassium 2,3-dimethyl- C
silane maleimide

4 3-aminopropyl-trimethoxy- 2,3-dimethylmaleic A
silane anhydride tri-n-propoxysilane (N-vinyl)-2,3-dimethyl- B
maleimide **
6 di-n-propoxy-methylsilane (N-vinyl-2,3-dimethyl- B
maleimide **
7 dicyclohexyloxy- CH3 methylsilane I/CO\ B
il ~ -.('C'H2)2-0-CH=CH2 _ . CH3 8 H2N-(CH2!2-NH (CH2)3 i-OCH3 2~3-dimethyl- A
t CH3 maleic anhydride ;
:

~1 465~C!

Table I (continuation) Ex- Silane of the formula Monofunctional jProcess ample -2 compound analogous to of pre-No. H-$i-R formula V paration R
or or Silane of the for- Monofunctional compound mula III analogous to formula II ¦
or or Silane of the for- Monofunctional alkali mula VIII metal compound analogous to formula VII

9 di-n-propoxy- ~ B
methylsilane ¦l~ i 2 \ / 2 . CH3 (preparation according to Example c) di-n-propoxy- I il N-CH=CH B
methylsilane / CO 2 ¦ * (Preparation accor- *** (disclosed in the pub-ding to Example a) lication by R.H. Yocum and E.B. Nyquist ** (Preparation accor- "Functional Monomers", ding to Example b) volume 2, page 234;
New York: Dekker (1974)) 65~

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Example 15 (Process B) CH3\ ~CO C1 2H5 I! ~ - C - CH = CH - Si - CH3 3 C2H5 0-o~ ~.
. = . .

Analogously to Example 2, a solution of 8.4 g (0.038 mol) of N-[l,l-diethyl-propargyl]-2,3-dimethyl-maleimide [prepared by reacting 2,3-dimethylmaleic anhydride with l,l-diethyl-propargylamine; boiling point 136-140C/2666.6 Pa] in 10 ml of dry xylene is reacted with a solution of 8.8 g (0.038 mol) of methyldiphenoxysilane in 5 ml of dry xylene, the reaction being catalysed by 0.5 ml of a 0.2% solution of hexachloroplatinic-IV acid in n-octanol. After heating at 120C for one hour, the reaction mixture no longer displays the characteristic-band of the H-Si grouping at 2,200 cm in the IR spectrum. After removing the platinum catalyst by stirring for 2 hours with 1 g of active charcoal and then filtering, the solvent is removed in vacuo, finally at 50C and under 0,133 Pa. The product is obtained in the form of a yellowish, viscous oil and is employed as an adhesion promoter without further purification. Yield 15.9 g = 92% of theory.
Elementary analysis for C26H31No4Si:
calculated C 69.46% H 6.95% N 3.11% Si 6.25%
found C 69.2% H 7.3% N 3.1% Si 6.5%.

Example 16 (Process B) --3\./ ~ 1 \._./

CH3 C0 0_-\ H /-Analogously to Example 15, 184 g (1.11 mols) of N-allyl-2,3-dimethyl-maleimide and 138 g (1.12 mols) ot methyldichlorosilane, in 1,000 ml , .

- 1:146560 of dry xylene as the solvent, are reacted at 100-115C, the reaction being catalysed by 2 ml of a 0.02 molar solution of H2PtC16 in diethylene glycol dimethyl ether. The product is distilled under a high vacuum; boiling point 98-101C/0.133 Pa. Yield 168 g = 54% of theory- Elementary analysis for ClOH15C12N02Si:

calculated C 42.86% H 5.40% Cl 25.3% N 5.0% Si 10.02%
found C 42.4% H 5.5% Cl 25.0% N 5.1% Si 10.2%.

16.8 g (0.06 mol) of N-[3-(methyl-dichlorosilyl)-n-propyl]-2,3-dimethyl-maleimide are dissolved in 200 ml of dry diethyl ether.
A solution of 12 g (0.12 mol) of cyclohexanol and 13.15 g (0.13 mol) of triethylamine in 100 ml of diethyl ether is added slowly dropwise at 20-35C. After the addition is complete, the reaction mixture is refluxed for 1 hour and cooled, the triethylamine hydrochloride which has precipitated is filtered off and the filtrate is freed from the solvent in vacuo. The residual colourless oil is distilled under a high vacuum; boiling point 157-159C/0.133 Pa. Yield 19.5 g = 80~o of theory.

Use Example I

Preparation of the product of the formula IX (Process D) 0-n.C3H7 H3C CH3 0-n.C3H7 ~CO~ CO\
3 1 2 2 \C0 ~ co/ 2 2 1 3 0-n.C3H7 H3C CH3 0-n.C3H7 A well-stirred mixture of 20 g (0.063 mol) of 2-(2,3-dimethyl-maleimido)-ethyl-di-n-propoxy-methylsilane [prepared according to Example 6] and 90 ml of dry acetone is irradiated under nitrogen in a water-cooled radiation apparatus (150 watt mercury high-pressure lamp) ' ' ' ~ ' ,., ., , . ,, :
.. . . . .
.
. .
.

,' ' ' - , , . ' ,: ' 1~465~0 until a thin layer chromatogram (solvent chloroform) of the reaction mixture shows no further starting material. The solution is then evaporated and the residue is recrystallised from 120 ml of n-hexane.
After drying under a high vacuum, N,N'-bis-[2-(di-n-propoxy-methyl-silyl)-ethyl]-1,2,3,4-tetramethylcyclobutane-1,2,3,4-tetracarboxylic acid diimide is obtained in the form of a crystalline white powder;
melting point 151C; yield = 11.2 g (56% of theory).

Use Example II
a) Impregnation of glass fabric: Glass fabric, so-called E-glass, which has a weight of 280 g/m and satin weave and has previously been de-sized by the action of heat to a residual size content of about 0.1% by weight, is impregnated with 2% solutions of the adhesion promoters obtained according to Preparation Examples 24, 1, 6, 7, 16 ?
17 and 36 and of known adhesion promoters. The adhesion promoter solutions are applied by the dipping process at an impregnation speed of 0.5 m/minute and are then dried for 20 minutes at 180C in a circulation air oven.

Prepregs are obtained which have an adhesion promoter content of about 0.09 to 0.12% by weight, based on the glass.

The adhesion promoters (finishes) used are:
1) No adhesion promoter 2) Vinyl-tris-(2-methoxyethoxy)-silane ("Silan A 172"~from Union Carbide); % solution in N,N-dimethylformamide (DMF) 3) y-Aminopropyl-triethoxysilane ("Silan A llOO'~from Union Carbide);
2% solution in DMF
4) Chromium chloride-methacrylate complex ("Volan-A" ~ form DuPont);
2% solution in DMF

5) The product according to Example 1 of U.S. Patent 3,755,354 (y-maleimidopropyltriethoxysilane); 2% solution in DMF

6) The diimide according to Example 4 of U.S. Patent 3,901,913;
2% solution in DMF
.

, '. .

iS6(~

7) The diimide according to Example 2a of German Offenlegungsschrift 2,504,791; 2% solution in DMF
I) Adhesion promoter according to Preparation Example 5; 2% solution in DMF
II) Adhesion promoter according to Preparation Use Example I; 2%
solution in DMF

b) Production of co er-coated laminate sheets: 1.0 mol of N,N'-4,4'-_ PP
diphenylmethane-bis-maleimide is dissolved at 100C in 500 g of furfuryl alcohol and the solution is cooled to 25C. 0.4 mol of 4,4'-diaminodiphenyl-methane are dissolved at-25C in 200 g of 2-methoxyethanol (methylene glycol monomethyl ether). The two solutions are combined and mixed well. Using this solution, the glass fabric finished in accordance with section a) is impregnated at 25C by the dipping process and then dried in a circulating air oven for 18 minutes at 180C (resin content of the resulting prepregs 39%
by weight). 10 layers of the impregnated fabric are then pressed hot between two 35 microns thick copper foils, which have been pre-treated by electrolytic surface-coating with brass. The press is initially kept under a light contact pressure for 2-3 minutes and the pressure is then increased to 392.28 x 104 Pa and the material is pressed for one hour at 180C. The test pieces are then removed from the press and post-cured for a further 6 hours in an oven at 240C
(resin content of the resulting laminate sheets 35% by weight).

Properties of the copper-coated laminate sheets thus obtained:
Flexural strength in N/mm according to ISO/R 178; a) initial value;
b) after aging for 10 days at 270C.
Absorption of water in % by weight after 24 hours at 23C. The measurements are carried out on flexural test pieces according to VSM
Standard 77,103.

.

.
' ' ' .

11~6S~

Dielectric loss factor tg ~/50 Hz according to DIN 53,483;
________________________ ________ a) initial value measured at 23C; b) after storing for 6 hours in boiling water.
Dielectric constant ~ /50 H~ according to DIN 53,483;
a) initial value measured at 23C; b) after storing in boiling water for 6 hours.
ISO/R = _nternational Standards Organisation/Recommendation;
VSM = Verein Schweizerischer Maschinenindustrieller; DIN = Deutsche Industrie Norm.

The results are given in Table III below. Numbering of the test products and of the test pieces is the same as under a).

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_ __. ____ ._ ____.__ ~ o ~r ~ c~
o u, a~ O O O . ~ ~
Z _ _ __~. ~___ u~ ~ ~ ~ n O
SJ ~ ~ O O O ~ U~
.' U _ __ _._ _~
., E~ ~ c~l ~ ~ o~ ~ ~ ~
Lr) ~ O O ~ ~D 1`
_ ~ C~l _______ . _.___~.
~ 1~ 00 ~ 1~ ~ ~
~ O ~ t U~ U~
_ __ .. ..~ ._ . ~ 0 00 O ~ ~ U~ U~

_ ____,____ ____. __~.___~_. ___.___ _ ~ ~o~ ~0 o u~ ~ a~
;: _ ~ ~
_~ ~: UO ~1 u a) 41 ~ Ll ~ S C d O
D~ ~ O ~J U~ (1) U~
C d C ~ ~ ~ ~ ~ ~ ~
1~ J O D ~1 ~> 0 3 U ~ O ~
o ~ '~ ~ ~ d s~ ~--I N t~
~1 ~ . ,, . ,~ J~ SJ O ~ ~ ~ rl h ,1 :~
~_~ . ~ ~ ~ d ~ ~ . r~
,J X E~ ~ O ;, ~ ~ ~ H <~ ~ ~1 \ H ~ ,Q ~O
.~ ~ Q) E3 u~ ~ ~ O o rd ~1 \ r~ ~ ~ O ~ ~ .,~
E~ _~ ~ ,."~ o._ a,,,~ ,,~ ,.~ .~.~.,~.~, ~,, ." ' .

'' ' :. .

Claims

WHAT IS CLAIMED IS:

1. A compound of the formula (I) in which R1 and R2 independently of one another are methyl, ethyl, phenyl, vinyl, chlorine or a group -OR, R3 is-chlorine or -OR, R is alkyl having 1-10 C atoms, cycloalkyl having 5-8 C atoms or phenyl, A is one of the divalent radicals -(CH2)a-, -C(R10)2-CH=C(R11)-, -C(R10)2-CH(R11)-, -(CH2)b-G-(CH2)c-, phenylene-(CH2)d-G-(CH2)c-, phenylene-(CH2)d-, or and in these divalent radicals A the bond to the Si atom is in each case effected via the bond on the right-hand side, R10 is hydrogen, methyl or ethyl, R11 is hydrogen or alkyl having 1 to 10 C atoms, a is a number from 1 to 10, b and c independently of one another are a number from 1 to 6, d is a number from 0 to 6, G is -CH(R11)-, -NH-, -N(R11)-, -O- or phenylene and M is -O-, -NH- or -N(R11 )-, and in which Y is or R12 is hydrogen, methyl, phenyl, -CN or halogen, R13 is methyl, phenyl, -CN or halogen and R8 is alkylene having 3 or 4 C atoms, which can be branched and can be interrupted by an O-atom, or is one of the radicals , or , with the proviso that A cannot be or if R12 and R13 are each methyl.