CA1072975A - Sulphur-containing organosilicon compounds, processes for their production and their use as adhesion promoters - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE:
Sulphur-containing organosilicon compounds having the general formula wherein R represents a C1-8-alkyl, cycloalkyl, C1-10-alkoxy alkyl or the phenyl radical, R' represents an optionally branched alkylene radical with 1 to 6 carbon atoms, a cycloalkylene, pheny-lene or benzylene radical, R'' represents an oxygen or sulphur atom, R"' represents a hydrogen atom or a methyl group, n = 1 or 2, and x = 1 or 2. These compounds are suitable for use as adhesion promoters between organic and inorganic media.
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Description

- ~072975~
'rroisdo~E, 24. 2. 1975 OZ 75 017 (2437) Dr. Sk/Sch DYNAMIT NOBEL AKTIE:NGESE:LLSCH~FT
Troisdorf, District of Cologne Sulphur-containing organosilicon compounds, processes for their production and their use as adhesion promoters The present invention relates to sulphur-containing 4rganosilicon compounds which are suitable for use as adhesion promoters,between organic and inorganic media.
The invention also relates to processes for producing these sulphur-containing organosilicon compounds.
The new sulphur-containing organosilicon compounds correspond to the general formula (Ro)4-n-si [ R ~Sx C l Cl~2 ]
R
in which represents a C1 8-alkyl-, cycloalkyl-, C1 10-alkyloxy alkyl-, phenyl radical, R' represents an optionally branched alkylene radical containirg fro~n 1 to 6 carbon atoms, a cycloalkylene, phenylene or benzylene radical, .

- 2- ~ .

,. . . ~ ~r . . ' . . ' ~ :

~ ~07Z975 R'' represents O;S
R''' represents H;CH3 x = 1 or 2 n = 1 or 2.
The invention also relates to the siloxanes obtained by hydrolysis on the compounds of formula (1).
In the process according to the invention, the sulphur-containing organosilicon compounds corresponding to formula (1) are obtiained by reacting the corresponding mercaptoalkylsilicon compounds corresponding to the general formula (R0)3-Si-R'-SH (2) in which R, R' have the same meaning as in formula (1), with methacrylic acid, acrylic acid, monothiomethacrylic or acrylic acid derivatives corresponding to the general formula x-f-CI =CH2,, R"R"' in which R" and R"' have the same meaning as in formula (1), and X represents a reactive group such as Cl, Br, -NH2, CH30-, in the absence of heat in the presence of polymerisation inhibitors and tertiary amines. The reactive group X must be able to react with the proton on the sulphur atom;
in this way the compound HX is liberated and an S-C-bond is formed.
Particularly suitable mercapto silicon compounds are, for example, ~-mercaptoethyl trimethoxy silane or ., ~ .
~-mercaptopropyl trimethoxy silane. However, it is also possible to use the corresponding ~-mercaptobutyl or -hexyl-or ~-mercaptophenyl trimethoxy or triethoxy silanes. These compounds are produced by generally known methods.
Typical acrylate and methaarylate compounds ' .

, . .

-~07Z975 ,,, suitable for use in accordance with the invention are metha-crylic acid chloride, acrylic acid chloride or the amides of acrylic and methacrylic acid.
However, it is a]so possible to use as compounds corresponding to aeneral formula (3) the Cl 4-alkyl esters of acrylic or methacrylic acid. The preferred esters are the methyl esters.
The temperatures required for the reaction, the choice of the solvent and of the catalyst re$uired, if any, must be adapted to thelparticular nature of the acrylic and methacrylic compounds used. Thus, it is advisable in cases where acid halides of methacrylic or acrylic acid are used to carry out the reactions in the presence of tertiary amines and polymerisation inhibitors at temperatures around OC.
On the other hand, in cases where esters of methacrylic acid and acrylic acid are used, it is of advantage to carry out the reaction in the presence of transesterification catalysts and polymerisation inhi~bitors known ~ se at temperatures of from 40 to 60C and optionally in vacuo.
Titanium esters are examples of typical trans-esterification catalysts. Typical inhibitors suitable for the process according to the invention are hydroquinone and di-tert.-butyl paracresol.
The new sulphur-containing organosilicon compounds may also be obtained by reacting alkenyl thioacrylate and alkenyl thiomethacrylate compounds corresponding to the general formula RIV~

C~12 CH l I J -SX- I_C_c~2 ~ (4 ~

- . . , , : , . . .

~072975 in which R'' = O;S
R = HjCH3 RIV = or different from RV = H, alkyl, cycloalkyl, branched - alkyl, phenyl group, and a = 1 - 4 with alkoxy hydrogen silanes corresponding to the general formula - 4-b b b = 1,2 in the presence of the above-mentioned inhibitors with Pt-compounds and in the presence or absence of inert organic solvents.
. The following compounds are mentioned as typical 1 representatives of the alkenyl thioacrylates and alkenyl , thiomethacrylates which may be used in accordance with the invention:

CH2=CH-CH2_S C_f_CH2 (6) . O H
.: ....... 20 ....
, .

. ..
.

. :~
, ..
: ' ' ~-,~ ' ' ' ' ' ' ' , ., ~ ' , . . .
,, . , , ~ , :
.
,. , . . , . : :
~ . . . . . .

~ ~072975 CH2=CH-CH2-S-CI--C=CH2 ( 7 ) CH 2 = CH - I H _ S _C _ l = CH 2 ( 8 ) :

CH2-CH-CH2-CH2-s-lcl-f=cH2 ( ) . ,. ~:, O H

Particularly suitable alkoxy silanes are trimethoxy silane, triethoxy silane, dimethoxy silane and diethoxy silane.
However, the reaction may also be carried out with tributoxy silane or triethoxy methoxy silane.
Suitable platinum compounds are H2Pt C16 or complex Pt(IV)compounds such as, for example, the Pt-mesityl oxide complex (cf. German Patent No. 1,937,904).
Suitable polymerisation inhibitors are such compounds as hydroquinone, quinone in conjunction with hydroquinone, aminophenols.
; The silanes according to the invention are soluble in low concentrations in aqueous medium with hydrolysis, may be applied to firm inorganic surfaces of fillers and reinforcing materials, oxides and metals by dip-coating, spread-coating or spray-coating and hardened by drying. However, water-containing solvents in which the silane is dissolved may also be used for pretreatment.
In order to produce reinforced or filled articles, the substances pretreated with the silanes according to the inven-tion are wetted with resins containing aliphatic unsaturated monomers, , .. . .

. ~' I ' , ~ .

.' . ' '' . ,: ' , . ' . . , . - ' ' . ' . . ,' ' . ' such as for example polyester styrene resins, and the bond hardened by polymerisation.
The interface between resin and inorganic material is formed on the one hand by reaction of the unsaturated double bonds of the resin and of the silane and on the other hand by reaction of the silanol groups formed during hydrolysis with the inorganic metallic surface. The shaped articles obtained showextremely high strengths, the silanes according to the invention being superior in this respect to the hitherto known and used~products ~methacrylate and vinyl silanes), as shown by the following tests.
Examples of the aliphatic unsaturated monomers which may be used for producing the reinforced or filled composite materials described above are styrene, acrylonitrile-butadiene-styrene, acrylonitrile-styrene, styrene-butadiene, isobutene, ethylene, propylene, vinyl acetate, vinyl chloride, vinylidene chloride and methyl methacrylate. The polymers produced by polymerisation may be rigid materials, for example polyester resins, or elastomeric materials, for example styrene-butadiene rubber.
. . I
The oxidic/metallic surfaces, for whose pretreatmentthe aforementioned silanes are used in accordance with the in~ention, include both oxidic and metallic surfaces and also surfaces of synthetically produced products. Examples of mineral products are asbestos, mica, quartz, corundum, diatomaceous earth, also iron oxides, chromium oxides, titanium oxides.
Examples of the synthetic products containing `1~ oxidic surfaces are glass fibres, glass cloths, glass beads, . . -~ electrocorundum, calcium carbonate, Fe203, CrO2. Examples of metals are Al, Fe, Zn, Mg, Sn, Ti and also alloys containing these metals as their principal constituents.

_ 7 _ The silane solutions are used in cor.centrations oE
from 0.05 to 5 '-Ol depending upon the specific surface of the material to be treated. Normally the oxidic/metallic surface is pretreated with the particular silane in order to obtain a stronger bond with the polymer. However, the same eEfect may also be obtained by mixing with the polymer small quantities (from 0.1 to 5 % by weight, based on the polymer) of the corresponding silane. The polymer may be both a duroplast and also a thermoplast.

196 g (1 mole) oE y-mercaptopropyl trimethoxy silane, 106 g (1.05 mole) of triethylamine, 10 9 of hydro-quinone and 1000 ml of xylene are introduced into and cooled while stirring to 0C in a 2 litre three-necked flask equipped with a reflux condenser, a dropping funnel, a stirrer and a cooling system for the flask. 104 g (1 mole) of methacrylic acid chloride are then added dropwise from the dropping funnel over a period of 1 hour. After the cooling system has been removed, the contents of the flask are stirred for 1 hour, after which the triethyl ammonium hydrochloride precipitated is filtered off. The filtrate is subjected to fractional distillation. 135 9 (51 ~) of a colourless liquid with the following properties distil over at 127C/2 Torr:
Molecular weight : theoretical 264 observed 26~
~eEractive index n25 : 1.~511 y (~ ) : 1.077 :
~ . . ., . . , - .
.- . ': . ' ' ' ' , , . .: .

. . - . :. .- : . , : :
.... : .
., .. : : . , . . . : .
', ~ , , -, .

. . - . : : :
.:
-. . .
~- : ., , ~ ,,:

.. _ , .. ..

~l.emental analysis: theore~i.c~l o~serv~d C 45.4 ~/~ 45.2 ~/0 H 7,6 % 7.7 %
0 24.2 % 24.0 /O
Si 10.6 % 10.7 /O
S 12.1 % 12.0 %
Accordingly, the product found has the formula _o)3-si-cH2-cll2-cl-l2-s~ =cH2 0 Cl-~3 EXA
224 g (1 mole) of ~-mercaptoethyl triethoxy silane, 1 106 g (1,05 mole) of triethylamine, 10 g of hydroquinone and 1000 ml of xylene are intraduced into and cooled ~o -5C in the apparatus described in Example 1. 104 g (1 mole) o~
methacrylic acid chloride are added dropwise over a period of 1.5 hours-. After the cooling system has been removed, the contents of the flask are stirred for 1 hour~ The triethyl ammonium hydrochloride is filtered off and the filtrate subjected to fractional distillation in vacuo.
157 g (54 %) of a colourless liquid with the following properties distil over at 104C/2 Torr:
~olecular weight: theoretical 292 observed ; 311 Refractive index n25: 1.4691 Density (d~ ): 1.097 Elemental analysis; theoreticalobserved C ` ~9.3 /O ~9.0 %
H 8,2 % 7.9 IO
.() 21~9 ~/o 22~3~/o S i 9 ~ 6 % 'I O ~ O %
S 11~6 % 11~65 /0 ~

r According, the product found has the fQrmula:
2 5 )3 Si~C1l2-CH2-S-C-f-CH

196 g (1 mole) of ~J-mercaptopropyl trimethoxy silane, 106 g (1.05 moles) of triethylamine, 10 g of hydroquinone and 1000 ml of xylene are introduced into and cooled to -10C
in the apparatus described in Example 1. 90 g (1 mole) of acrylic acid chloride are added dropwise with vigorous stirring over a-periodlof 1.5 hours. The contents of the flask are stirred for 1 hour at ~5C, after which the triethyl ammonium hydrochloride is filtered off. Following the addition of 5 g of hydroquinone, the filtrate is subjected to fractional distillation in vacuo. 120 g (48 %) of a colourless liquid with the following properties distil over at 125C/2 Torr:
Molecular weight: theoretical 250 observed 248 Refractive index nD : 1.4491 Density (d45): 1.056 Elemental analysis: theoretical observed C 43.2 % 43.3 ~
H 7.2 ~ 7.3 % ~-o 25.6 % 25.2 %
Si 11.2 % 10.9 S 12.8 % 12.7 The product found has the formula:
(Cll3O)3-Si-(CH2)3-S-CI-Cll=CH2 ` 30 196 g (1 mole) of ~-mercaptopropyl trimethoxy silane, 106 g (1.05 moles) of triethylamine, 10 g of hydroquinone and 1000 ml of xylene are introduced into and cooled to -10C

.. ..
.
.
, . , ,, . ~ , . .

-~ 107Z975 in the apparatus described in Example 1. 120 g (1.0 mole) of thiomethacrylic acid chloride are added dropwise with intensive stirring over a period of 2 hours during which the reaction tempe-rature is kept constant. The contents of the flask are then stirred for 1 hour at +5C, after which the triethyl ammonium hydrochloride is separated off from the filtrate. Following the addition of 14 g of hydroquinone, the filtrate is subjected to fractional distillation in vacuo. 59 g (21%) of a pale yellowish liquid with the following properties distil over at 140C/2 Torr:
Molecular weight: theoretical 280 observed278 Refractive index nD5: 1.4702 Density (d45): 1.10 Elemental analysis: theoreticalobserved C 42.8 % 42.5 %
H 7.1 % 7.0 %
o 17.1 % 16.9 ~
Si10.0 % 9.8 %
S 11.4 % 11.5 %

Structural formula (CH3-O)3-si-CH2-CH2-CH2-S-C-C=CH2 122 g (1 mole) of trimethoxy silane and 250 ml of toluene are introduced into a 2 litre double-jacketed three-necked flask connected to a thermostat and equipped with a stirrer, a dropping funnel and a reflux condenser. 50 mg of H2PtC16.6 H2O

dissolved ln lO ml of acetone and lO g of hydroquinone are added to this mixture.
The addition of 149 g (1.05 moles) of allyl thiometha- -crylate is commenced at a temperature of the flask contents of 68C. The addition is over after 15 minutes. During addition of the allyl thiomethacrylate the temperature is kept constant by cooling at 72C. The reaction mixture is then left to react out for 15 minutes, followed by cooling to room temperature.
Following the addition of 15 g of hydroquinone, the mixture is worked up _ vacuo in a reaction evaporator. 135 g (51%) of a colourless liquid distil over at 123C/l Torr, its properties being the same as those of the substance obtained in Example 1.

1% by weight of the silane H2C =CH-COS-(CH2)3Si(OCH3)3 ','r and benzoyl peroxide were added to styrene, followed by polyme-risation on a glass plate. The polymer obtained adhered much more firmly to the surface of the glass than a corresponding silane-free sample. This firm bond remained intact even after storage for 4 hours in'water at 30C.

; Water-sized glass filaments are dipped into a 0.25%
i~ solution of a-methacryl thiopropyl trimethoxy silane in ethanol, left to drain and then dried for 15 minutes at 130C in a recirculating-air drying cabinet. The glass filaments thus pretreated are then wetted with unsaturated polyester resin, drawn intb 4 mm thick glass tubes and hardened for 2 hours , ` ':.:

F` I - 12 -at 100C. After the finished GFR-UP-resin round bars have been dissolved out, they are post-hardened for 15 hours at 130C and then tested for flexural strength in accordance with DIN 53 452.
The f]exural strength of test specimens which had been stored in boiling water for 72 hours and then wiped dry is also determined. For comparison, the same tests were carried out in the case of y-methacryloxy propyl trimethoxy silane.
% Silane in the size Flexural strength of GFR-UP-resin round bars in kp/cm2 Flexural strength dry wet 0.25 ~ ~-methacryloxy propyl trimethoxy silane10800 7400 0.25 ~ ~-methacryl thiopropyl trimethoxy silane12400 9200 GFR-UP-resin round bars which had been prepared from 0.5 ~ solutions of ~-methacryl thioethyl triethoxy silane were tested for their flexural strength in the same way as in Example 7. The following results were obtained:
dry: 11400 kp/cm wet: 10300 kP/cm2 13XAMPL,E 9 Water-sized glass fibres are wetted as in Example 7 with UP-resins, to which 0.5 % of ~-acryl thioethyl'triethoxy silane has been added, and processed into GFR-UP-resin round bars. The flexural strengths measured correspond to those of Example 7.

, .
.

1C~7Z975 1 ~ by weight of H~C=C - C-S(CH2)3-Si(OCH3)3 S

was added to a standard commercial-grade lacquer based on methacrylic a~id ester which was then applied to glass plates and dried in air for 24 hours. The lacquer was then heated for 1 hour to 120C and the adhesion of the lacquer tested by Erichsen's lattice cut itest. Adhesion was very good. In contrast, the adhesion of the lacquer to non-pretreated glass plates was very poor.
Similar test results were obtained with aluminium plates.

- : ' '

Claims (10)

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

1. A process for the preparation of sulphur-containing organosilicon compounds having the general formula:

(I) wherein R represents a C1-8-alkyl, cycloalkyl, C1-10-alkoxy alkyl or phenyl radical, R' represents an optionally branched alkylene radical with 1 to 6 carbon atoms, a cycloalkylene, phenylene or benzylene radical, R" represents an oxygen or sulphur atom, R"' represents a hydrogen atom or a methyl group, n is 1 or 2, and x is 1 or 2, which comprises:
a) reacting a mercapto compound of the general formula:
(RO)3-Si-R'-SH (II) in which R and R' are as defined above, with a compound having the general formula:

(III) in which R" and R"' are as defined above and X represents a halogen atom, an alkoxy group, an amido group or a hydrazide group, in the presence of a polymerization inhibitor and of a tertiary amine or a transesterification catalyst, or b) reacting a mercapto compound having the general formula:

(IV) in which R", R"' and x are as defined above, RIV and RV which are identical or different and each represents a hydrogen atom, a linear or branched alkyl, a cycloalkyl or a phenyl radical, and a is 1,2,3 or 4, with a compound having the general formula:
(RO)4-n-Si-Hn in which R and n are as defined above, in the presence of a polymerization inhibitor and a platinum compound.

2. A process according to claim 1, wherein the compound of formula (III) is an acid halide of methacrylic or acrylic acid and the reaction is carried out in the presence of a tertiary amine and a polymerisation inhibitor.

3. A process according to claim 2, wherein the reaction is carried out at a temperature of about 0°C.

4. A process according to claim 1, wherein the compound of formula (III) is an ester of methacrylic or acrylic acid and the reaction is carried out in the presence of a transesterifica-tion catalyst and a polymerisation inhibitor.

5. A process according to claim 4, wherein the reaction is carried out at a temperature of from 40 to 60°C.

6. Sulphur-containing organosilicon compounds having the general formula :

(I) wherein R represents a C1-8-alkyl, cycloalkyl, C1-10-alkoxy alkyl or the phenyl radical, R' represents an optionally branched alkylene radical with 1 to 6 carbon atoms, a cycloalkylene, phenylene or benzylene radical, R" represents an oxygen or sulphur atom, R"' represents a hydrogen atom or a methyl group, n is 1 or 2, and x is 1 or 2, and the condensation products derived from these compounds.

7. A compound according to claim 6, having the formula:

.

8. A compound according to claim 6, having the formula:

.

9. A compound according to claim 6, having the formula:

.

10. A compound according to claim 6, having the formula:

.