DE10135305A1 - Branched organosiloxane copolymers with terminal silicon-carbon groups useful as antimisting additives and for decreasing aerosol formation in crosslinkable silicone coating compositions - Google Patents

Abstract

Branched organosiloxane copolymers with terminal silicon-carbon groups are new. Branched organosiloxane copolymers of formula (I) with terminal silicon-carbon groups are new. Y(-CnH2n-(R2SiO)m-Ap-R2Si-G)x (I) -R2Si-R<2>-(R2SiO)m (II) Y = one to three valent 1-25C hydrocarbon group, containing one or more hetero atoms selected from nitrogen, oxygen and silicon; R = monovalent, optionally halogenated 1-18C hydrocarbon group; A = a residue of formula (II); R<2> = divalent 2-30C hydrocarbon group, which can be interrupted by one or more oxygen atoms; G = a monovalent residue of formula CfH2f-2k-Z or a divalent residue of formula -CnH2n-, where the two bonds are bonds to a further Y group; Z = a monovalent terminal aliphatic hydrocarbon residue free from C-C multiple bonds, which is inert to SiH groups in hydrosilylation reactions, and which optionally comprises one or more hetero atoms selected from oxygen, nitrogen, boron, silicon, and titanium, or a monovalent polymer residue with more than 20 C atoms; x = 3-10; f, n = 2-12; k = 0 or 1; m = at least 1; and p = 0 or a positive number. with the proviso that the branched organosiloxane polymer contains on average at least one Z group. Independent claims are included for: (1) Preparation of the organosiloxane polymers (I) in a two step process; (2) A crosslinkable silicone coating composition with decreased aerosol formation comprising (X) an antimisting additive in accordance with the above, (A) organosilicon compounds comprising C-C unsaturation, (B) organosilicon compounds with silicon-bonded hydrogen atoms, (C) catalysts for the addition of silicon-bonded hydrogen to C-C unsaturation, and optionally (D) inhibitors; (3) A shaped body obtained by cross-linking the above coating composition; (4) A process for production of coatings by application of the crosslinkable composition to a surface, followed by crosslinking; and (5) A process for preparation of a coating of an adhesive material by application of the crosslinkable composition to the adhesive coating surface followed by crosslinking.

Description

The invention relates to branched organosiloxane (co) polymers, their branching from at least trivalent organic Building blocks consist and their ends of organic groups are formed, which are bound via Si-C.

The invention further relates to a method for their Production.

Branched organopolysiloxanes, their branching units correspond to conventional monoalkylsiloxy units are in US-A 5,670,686. From prefabricated siloxanes with three or four hydrogendimethlylsiloxy units are in one single-stage hydrosilylation process with branched siloxanes different end groups. More branched Polysiloxanes are not described, all branches correspond to conventional silicone chemistry.

The hydrogen intermediates such as tris [dimethylsiloxy] allylsilane are manufactured in a hydrolytic process and purified by distillation.

Higher molecular siloxanes can only be equilibrated can be obtained, the alkylsiloxy units only poorly functioning acid catalysis must be used since the basic catalysis for substances, the hydrogen siloxy groups contain, leads to chemical decomposition.

According to Polymer Preprints 34 (1), 77 (1993), more highly branched products can be obtained from an AB ₃ monomer by using tris [dimethylsiloxy] allylsilane as a monomer and, after noble metal catalysis, a highly branched carbosiloxane with hydrogendimethylsiloxy end groups, which is obtained with α-unsaturated ones organic compounds is implemented. This method, which works according to the polyaddition, requires the production of an extremely high-energy monomer, the handling of which represents a considerable safety risk. The branching is based exclusively on conventional T units (SiC _3/2 units). Siloxanes which contain dialkylsiloxy units are not described and are hardly available even with known methods. A similar methodology is described in PMSE-Prepr. 80, 139 (1999): H-dendrimers are obtained from bis [dimethylsiloxy] methylvinylsilane by polyaddition and then reacted with α-unsaturated organic compounds.

DE-A 195 22 144 describes branched siloxane copolymers described by implementing compounds with at least 3 reactive to hydrogen silylation Double bonds with α, ω-dihydrogen siloxanes and the following Implementation of the intermediates generated in the 1st stage with α, ω- Services such as 1,5-hexadiene can be obtained. For production of however, this process is branched siloxanes unsuitable, since only insoluble gels are obtained, especially if for economic reasons and because of desired product purity the use of larger Excesses of α, ω-dienes should be avoided. Furthermore, branched products can be compared Hydrogen siloxanes are inert, not produced in this way become.

Regular dendrimers are available after polymer preprints 39 (1), 581 (1998) when tetraallylsilane is repeated with Methyldichlorosilane and then with Allyl-Grignard solution is implemented. The dendrimers are allyl functional and can be hydrosilylated in a subsequent reaction.

Classic dendrimers are obtained according to US-A 6,184,407, if Siloxanes with multiple SiH groups with vinylalkoxysilanes are implemented, the polymer-bound alkoxy groups exchanged hydrolytically for siloxy groups containing SiH become, and thus dendrimers arise, which in turn with Vinyl components can react. The manufacturing process is complex and expensive.

The object of the present invention was branched to strong to provide branched organosiloxane (co) polymers which are organic groups bound at the ends Si - C, and those in a simple process can be made without elaborate multi-stage processes have to be run through and being the use of expensive and dangerous to handle Educts should be avoided.

So it should be avoided that expensive to manufacture "monomeric" building blocks, such as tris [dimethylsiloxy] allylsilane Find use, which also have no variability Allow chain length between the branches and also involve a high safety risk in handling. The object is achieved by the invention.

The invention relates to branched organosiloxane (co) polymers containing structural elements of the formula

Y [-C _n H _2n - (R ₂ SiO) _m -A _p -R ₂ Si-G] _x (I)

in which
Y is a tri- to tetravalent, preferably tri- to tetravalent, hydrocarbon radical which can contain one or more heteroatoms selected from the group of oxygen, nitrogen and silicon atoms,
R can be the same or different and represents a monovalent optionally halogenated hydrocarbon radical having 1 to 18 carbon atoms per radical,
A is a radical of the formula -R ₂ Si-R ² - (R ₂ SiO) _m -, where R ^{2 is} a divalent hydrocarbon radical having 2 to 30 carbon atoms, which is separated by one or more oxygen atoms, preferably 1 to 4 oxygen atoms can be interrupted means
G denotes a monovalent radical of the formula -C _f H _2f-2k -Z or a divalent radical of the formula -C _n H _2n -, where the second bond is to a further radical Y,
Z is a monovalent hydrocarbon radical free from terminal aliphatic carbon-carbon multiple bonds, which is inert towards SiH groups in hydrosilylation reactions and can contain one or more heteroatoms selected from the group consisting of oxygen, nitrogen, boron, silicon and titanium, or with a monovalent polymer radical means more than 20 carbon atoms,
x is an integer from 3 to 10, preferably 3 or 4,
f is an integer from 2 to 12, preferably 2,
k is 0 or 1
n is an integer from 2 to 12, preferably 2,
m is an integer of at least 1, preferably an integer of 1 to 1000 and
p is 0 or an integer positive number, preferably 0 or an integer from 1 to 20,
with the proviso that the branched organosiloxane (co) polymers contain an average of at least one group Z.

The invention further relates to a method for producing the branched organosiloxane (co) polymers by in a first step
Compounds (I) of the formula which have at least three aliphatic double bonds

Y (CR ¹ = CH ₂ ) _x

where Y and x have the meaning given above and
R ^{1 represents} a hydrogen atom or an alkyl radical having 1 to 10 carbon atoms
with organopolysiloxanes (2) of the general formula

H (R ₂ SiO) _m -A _p -R ₂ SiH

where A, R, m and p have the meaning given above, are reacted in the presence of catalysts (3), so-called hydrosilylation catalysts, which promote the addition of Si-bonded hydrogen to αliphatic multiple bond,
and in a second step the branched intermediates (5) thus obtained containing Si-bonded hydrogen atoms with organic compounds (4) of the formula

C _f H _2f-2k-1 -Z

selected from the group of
if k = 0: H ₂ C = CR ³ -Z (4a) and
if k = 1: R ⁴ C ~ CZ (4b)
wherein R ³ and R ^{4 have} the meaning of R ¹ , and
f, k and Z have the meaning given above, in the presence of catalysts (3) which promote the attachment of Si-bonded hydrogen to aliphatic multiple bonds.

The organosiloxane (co) polymers with a branched structure basically contain chain-like siloxane blocks, the ends of which are each connected to the structural elements Y and Z via a C _f H _2f or C _f H _2f-2 bridge. The more siloxane blocks are connected to elements Y on both sides, the more branched are the products produced. In general, the organosiloxane (co) polymers according to the invention are constructed in such a way that siloxane blocks and organic blocks alternate with one another, the branching structures and the ends consisting of organic blocks.

In the organosiloxane (co) polymers according to the invention, this is Ratio of end groups Z to branch groups Y (Z / Y ratio) preferably 1.0 to 2.0, preferably 1.1 to 1.5.

The organosiloxane (co) polymers according to the invention have preferably a viscosity of 50 to 50,000,000 mPa.s 25 ° C, preferably 500 to 5,000,000 mPa.s at 25 ° C and particularly preferably 1,000 to 1,000,000 mPa.s at 25 ° C.

Examples of radicals R are alkyl radicals, such as the methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, tert-butyl, n-pentyl, iso-pentyl, neo-pentyl, tert-pentyl, Hexyl radicals, such as the n-hexyl radical, heptyl radicals, such as the n-heptyl radical, Octyl radicals, such as the n-octyl radical and iso-octyl radicals, such as the 2,2,4-trimethylpentyl radical, nonyl radicals, such as the n-nonyl radical, Decyl residues, such as the n-decyl residue, dodecyl residues, such as the n-dodecyl and octadecyl such as the n-octadecyl; Cycloalkyl radicals, such as cyclopentyl, cyclohexyl, cycloheptyl and methylcyclohexyl; Aryl radicals, such as the phenyl, naphthyl, Anthryl and phenanthryl; Alkaryl residues, such as o-, m-, p- Tolyl, xylyl and ethylphenyl; and aralkyl residues, such as the benzyl radical, the α- and the β-phenylethyl radical.

Examples of halogenated radicals R are haloalkyl radicals, such as the 3,3,3-trifluoro-n-propyl radical, the 2,2,2,2 ', 2', 2-hexafluoroisopropyl radical, the heptafluoroisopropyl radical and Halogenaryl radicals, such as the o-, m- and p-chlorophenyl radicals.

The radical R is preferably a monovalent one Hydrocarbon radical with 1 to 6 carbon atoms, the Methyl radical is particularly preferred.

Examples of alkyl radicals R ¹ are the methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, tert-butyl, n-pentyl, iso-pentyl, neo -Pentyl, tert-pentyl, hexyl, such as the n-hexyl, heptyl, such as the n-heptyl, octyl, such as the n-octyl and iso-octyl, such as the 2,2,4-trimethylpentyl, nonyl, such as the n-nonyl radical and decyl radicals, such as the n-decyl radical. Is preferred. R ^{1 is} a hydrogen atom.

Examples of radicals R ² are those of the formula
- (CH ₂ ) ₂ -
- (CH ₂ ) ₄ -
- (CH ₂ ) ₆ -
- (CH ₂ ) ₈ -
- (CH ₂ ) ₁₀ -
-C ₆ H ₄ -
-C ₂ H ₄ O ₆ H ₄ O ₂ H ₄ -
-C (CH ₃ ) CH ₂ O ₆ H ₄ CH ₂ C (CH ₃ ) - and
-C ₂ H ₄ -norbornanediyl-.

Examples of radicals R ¹ apply in full to radicals R ³ and R ⁴ .

R ³ is preferably a hydrogen atom.

R ⁴ is preferably a hydrogen atom.

In the first process step, the addition of the SiH group from (2) to the CH ₂ = CR ¹ group of (1), the so-called hydrosilylation, leads to the formation of two isomers known to the person skilled in the art as follows:

The -C _n H _2n group in (I) of the organosiloxane (co) polymers according to the invention comprises this isomer formation and therefore preferably means the isomeric radicals -CHR ¹ -CH ₂ - of (i) and


of (ii) and n is therefore the total number of carbon atoms in the CH ₂ = CR ¹ group of (1). Since R ^{1 is} preferably a hydrogen atom, n is preferably 2.

In the method according to the invention, a type of Connection (1) or different types of connection (1) be used.

Examples of compounds (1) with which the branched organosiloxane (co) polymers according to the invention can be prepared are
1,2,4-trivinylcyclohexane,
1,3,5-Trivinylcyclohexane,
3,5-dimethyl-4-vinyl-1,6-heptadiene,
1,2,3,4-tetra vinylcyclobutane,
methyltrivinylsilane,
tetravinylsilane,
1,1,2,2-tetraallyloxyethane,
with 1,2,4-trivinylcyclohexane being preferred.

Examples of the radical Y are therefore those of the formula


being the rest of the formula


is preferred.

In the method according to the invention, a type of Organopolysiloxane (2) or different types of Organopolysioxane (2) can be used.

A largely linear polymer is used as the organopolysiloxane (2) used.

p is preferably 0.

m is preferably an integer from 5 to 400.

Organopolysiloxane (2) is in the first process step in such quantities that the ratio of Si bound hydrogen in organopolysiloxane (2) aliphatic double bond in compound (1) preferably at least 1.5, preferably 1.5 to 20, particularly preferably 1.5 is up to 5.0.

Since organopolysiloxane (2) is preferably used in excess everyone will react in the first process step aliphatic double bonds in compound (1), and it branched organosiloxane (co) polymers (5) are obtained which Have Si-bonded hydrogen atoms. In case of low molecular weight organopolysiloxanes (2) with p = 0 and m = 1-6 can by the subsequent distillative removal of the excess organopolysiloxane (2) intermediates (5) can be obtained practically free of organopolysiloxane (2). In in the other cases, excess organopolysiloxane (2) preferably left in the reaction mixture, whereby the Intermediates (5) are diluted. To soluble, d. H. Obtaining uncrosslinked intermediates (5) is therefore preferably a molar ratio of SiH in (2) to C = C in (1) of used at least 1.5. The required molar ratio depends on the structure of (1) and the index x and can be carried out by the specialist in individual cases through manual tests can be determined experimentally.

As catalysts (3) promoting the attachment of Si-bonded hydrogen to aliphatic multiple bonds, the same catalysts can also be used in the process according to the invention as have previously been used to promote the attachment of Si-bonded hydrogen to aliphatic multiple bonds. The catalysts are preferably a metal from the group of platinum metals or a compound or a complex from the group of platinum metals. Examples of such catalysts are metallic and finely divided platinum, which can be on supports such as silicon dioxide, aluminum oxide or activated carbon, compounds or complexes of platinum, such as platinum halides, e.g. B. PtCl ₄ , H ₂ PtCl ₆ .6H ₂ O, Na ₂ PtCl ₄ .4H ₂ O, platinum-olefin complexes, platinum-alcohol complexes, platinum-alcoholate complexes, platinum-ether complexes, platinum-aldehyde - Complexes, platinum-ketone complexes, including reaction products of H ₂ PtCl ₆ .6H ₂ O and cyclohexanone, platinum-vinylsiloxane complexes, such as platinum-1,3-divinyl-1,1,3,3-tetra-methyldisiloxane complexes with or without Content of detectable inorganically bound halogen, bis- (gamma-picolin) - platinum dichloride, trimethylene dipyridine platinum dichloride, dicyclopentadiene platinum dichloride, dimethyl sulfoxydethylene platinum (II) di-chloride, cyclooctadiene platinum dichloride, norbornadiene-platinum dichloride-platinum dichloride, platinum dichloride-platinum dichloride, platinum dichloride, platinum dichloride, platinum dichloride, platinum dichloride, platinum dichloride, platinum dichloride, platinum dichloride, platinum dichloride, platinum dichloride, platinum dichloride, platinum dichloride, platinum dichloride, platinum dichloride, platinum dichloride, platinum dichloride, platinum dichloride, platinum dichloride, platinum dichloride, platinum dichloride, platinum dichloride, platinum dichloride) Reaction products of platinum tetrachloride with olefin and primary amine or secondary amine or primary and secondary amine, such as the reaction product of platinum tetrachloride dissolved in 1-octene with sec-butylamine or ammonium-platinum complexes.

The catalyst (3) is in the first process step preferably in amounts of 0.2 to 20 ppm by weight (parts by weight per million parts by weight), preferably in amounts of 1 to 10 Ppm by weight, calculated as elemental platinum and related on the total weight of compound (1) and organopolysiloxane (2) used.

The first process step is preferably when printing the surrounding atmosphere, i.e. at around 1020 hPa (abs.), performed, but it can also be done at higher or lower Pressures are carried out. Furthermore, the first Process step preferably at a temperature of 20 ° C. up to 150 ° C, preferably 40 ° C to 100 ° C.

Since the at least three aliphatic double bonds Compound (1), e.g. B. 1,2,4-trivinylcyclohexane, at higher Temperatures tending to polymerize can occur in the first Process step preferably radical inhibitors, such as 4- Methoxyphenol, 2,6-bis (tert.butyl) -4-methylphenol, Phenothiazine, hydroquinone or pyrocatechol also used become. The radical inhibitors are preferably in Amounts from 10 to 500 ppm by weight, based on the total weight on compound (1) and organopolysiloxane (2).

In the first as well as in the second process step preferably inert organic solvents are used become. Examples of inert organic solvents are Toluene, xylene, octane isomers, heptane isomers, butyl acetate, 1,2- Dimethoxyethane, tetrahydrofuran and cyclohexane.

The inert organic which may also be used Solvents can be used after the first or second Process step are removed by distillation or in Reaction mixture remain.

The organic compounds (4) contain aliphatic C-C- Double or triple bonds compared to Si-H groups in Hydrosilylation reactions are reactive and below Accumulate the formation of Si-C bonds.

If k = 0, the reactive group contains a double bond and the organic compound (4) is a compound (4a) of the formula H ₂ C = CR ³ -Z.

When k = 1, the reactive group contains a triple bond and the organic compound (4) is a compound (4b) of the formula of the formula R ⁴ C ~ CZ.

When the SiH group in the intermediate (5) is attached to the double or triple bond in (4a) or (4b), the formation of isomers known to the person skilled in the art occurs as follows:

The -C _f H _2f-2k group in (I) of the organosiloxane (co) polymers according to the invention comprises this isomer formation and therefore preferably means the isomeric radicals


and f is therefore the total number of C atoms in the H ₂ O = CR ³ group of (4a) or the R ⁴ C ~ C group of (4b).

Since R ³ and R ^{4 are} preferably hydrogen atoms, f is therefore preferably 2.

Examples of the H ₂ C = CR ³ group in the organic compound (4a) are
H ₂ C = CH-,
H ₂ O = C (CH ₃ ) - and
H ₂ C = C (C ₄ H ₉ ) - and
H ₂ C = C (C ₈ H ₁₇ ) -.

Examples of the R ⁴ C ~ C group in the organic compound (4b) are
HC ~ C-
CH ₃ C ~ O- and
C ₄ H ₉ C ~ C-.

The radical Z in bound to the double or triple bond (4a) or (4b) can contain carbon and hydrogen atoms also one or more heteroatoms selected from the group of Contain oxygen, nitrogen, boron, silicon and titanium and is in a hydrosilylation reaction against SiH groups not reactive.

The unsaturated compound (4) can thus have functional groups contain, such as hydroxy, ether, ester, amido, urethane, Urea, amino, oximo, imino, carboxyl, carbonyl or Epoxy groups. It preferably does not contain any groups that Significantly hinder the hydrosilylation reaction.

Examples of Z radicals are
- (CH ₂ ) ₅ CH ₃
- (CH ₂ ) ₉ CH ₃
- (CH ₂ ) ₁₅ OH ₃
-C (CH ₃ ) ₂ OH

Examples of radicals G are therefore

The unsaturated compound (4) can be monomeric, oligomeric or have a polymeric character. Therefore correspond to the definition of Z also organic residues, the polyether, polyester, polyurethane, Polyurea, polyamide, polyolefin, polyacrylate or Contain polyacetal. Are preferred as polymer residues Polyether, polyester, polyolefin and polyacrylate.

Examples of organic compounds (4a) are

Examples of organic compounds (4b) are
CH ~ CC ₆ H ₅
CH ~C-CH ₂ OH
CH ~ CC (CH ₃ ) ₂ OH
CH ~ C-CH ₂ OC ₄ H ₉
CH ~C-CO ₂ H
CH ~ C-CO ₂ C ₂ H ₅ and
CH ~ C-CH ₂ O ₂ CNHC ₁₈ H ₃₇ .

Examples of oligomeric / polymeric organic compounds (4) are those oligomers / polymers that are reactive Multiple bond related to the hydrosilylation reaction contain. In particular, these are those started with allyl alcohol Polyether, subsequently allylated with alkanols Polyether, polycaprolactam started with allyl alcohol, and Olefins and acrylates that are anionically polymerized and ??? with an unsaturated cationic compound such as Dimethylvinylchlorosilane, can be terminated.

Optionally, olefins such as e.g. B. isobutene is also cationic polymerized and with an anionic compound such as a Alkenylgrignard, to be terminated according to the invention to produce used connections (4).

In the second process step, a type of compound (4) or different types of connection (4) can be used. One or more connections (4) can be made simultaneously or can be used one after the other and therefore several various functions in the branched according to the invention Organosiloxane (co) polymers can be incorporated.

In the second process step, the organic compound (4) used in such quantities that the ratio of aliphatic double bond in (4a) or aliphatic Triple bond in (4b) to Si-bonded hydrogen in the im intermediate obtained in the first process step (5) is preferably 0.5 to 1.5, preferably 1.05 to 1.5.

The compound (4) can be stoichiometric in excess or Deficit, based on the intermediate (5), used become. If a substoichiometric amount (4) is used, branched organosiloxane (co) polymers are obtained which additionally to the functional group Z introduced via (4) contain reactive SiH groups. A preferred version for the production of the branched according to the invention Organosiloxane (co) polymers is the use of at least an equimolar amount of (4), i.e. the use of the same or more of the reactive multiple bonds in (4), based on the SiH groups in (5). A preferred stoichiometric ratio is therefore in the range of 1.05 to 1.50.

When performing the second step, it is possible, compound (4) to the catalyzed intermediate (5) to dose or vice versa. However, the submission of the Compound (4) with catalyst (3), followed by the intermediate (5) is dosed. Provided the warmth of this Hydrosilylation reaction is rather low, will be advantageous Mixture of (4) and (5) at a suitable temperature with Catalyst (3) started, with adiabatic driving the heating of the reaction mixture is a measure of the Progress of the reaction itself is.

If the compound (4) is volatile, the excess Compound (4) are removed by distillation, otherwise remains them in the final product.

The catalyst (3) is in the second process step preferably in amounts of 0.5 to 50 ppm by weight (parts by weight per million parts by weight), preferably in amounts of 2 to 20 Ppm by weight, calculated as elemental platinum and related on the total weight of organic compound (4) and in intermediate obtained in the first process step (5) used.

The second process step is preferably when printing the surrounding atmosphere, i.e. at around 1020 hPa (abs.), performed, but it can also be done at higher or lower Pressures are carried out. Furthermore, the first Process step preferably at a temperature of 20 ° C. up to 150 ° C, preferably 40 ° C to 120 ° C, carried out.

Examples of the branched organosiloxane (co) polymers according to the invention are:
If 1,2,4-trivinylcyclohexane (1) is reacted with H (Me ₂ SiO) ₇ Me ₂ SiH (2) in the first process step and the intermediate product (5) containing Si-bonded hydrogen atoms obtained in the first process step with 1 in the second process step -Octen (4) is reacted, for example a compound of the formula is obtained:

If in the first process step methyltrivinylsilane (1) is reacted with H (Me ₂ SiO) ₁₉₀ Me ₂ SiH (2) and in the second process step the intermediate (5) containing Si-bonded hydrogen atoms obtained in the first process step with 3-methylbut-1-in -3-ol of the formula HC ~ CC (Me ₂ ) -OH (4) is reacted, for example a compound of the formula is obtained:

To produce the branched according to the invention Organosiloxane (co) polymers can steps 1 and 2 of inventive method also performed simultaneously become what depending on the type of compounds (1), (2) and (4) Products with modified properties may result, provided this is desired.

Likewise, steps 1 and 2 can be done in reverse order be performed. Here, organopolysiloxane (2) in Excess with compound (4) in the presence of catalyst (3) implemented and then the Si-bonded hydrogen atom containing intermediate with compound (1) in the presence of Catalyst (3) implemented. To reverse with the procedure Order of products with comparable product properties how to obtain with the normal preferred method a corresponding adjustment of the proportions of the used compounds (1), (2) and (4) required.

If the catalyst (3) is active over the 1st Retains procedural step, can be used for the 2nd procedural step there is also no further addition of catalyst (3) become.

Examples 1

In a glass flask with a mechanical stirrer, 108 g of 1,2,4-trivinylcyclohexane with 1840 g of an α, ω-dihydrogenpolydimethylsiloxane with an active hydrogen content (Si-bonded hydrogen) of 0.18% by weight and a viscosity of 9 mPa .s mixed at 25 ° C and then 1.9 g of a solution of a platinum-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex in dimethylpolysiloxane (so-called Karstedt catalyst) with a Pt content of 1 , 0 wt .-% added. The reaction mixture heats up to about 80 ° C. in a few minutes and is stirred at this temperature for about 1 h. A branched siloxane polymer having a viscosity of 220 mm ² / s at 25 ° C. and an active hydrogen content of 0.067% by weight is obtained. According to the principle of synthesis, all free siloxane chain ends consist of the highly reactive hydrogendimethylsiloxy units.

Example 2

100 g (67 mmol SiH) of that prepared in Example 1 Hydrogen siloxane polymer are mixed with 9 g of 1-octene (80 mmol C = C) mixed (C = C / SiH ratio = 1.2), heated to 100 ° C and with 0.5 mg of platinum in the form of that described in Example 1 Kartstedt catalyst solution started. A slight exotherm shows the course of the olefin addition, which takes about 2 hours is finished.

Testing for active hydrogen (Si-bonded hydrogen) results in more than 99% sales.

After removal of the excess olefin, a clear product with a viscosity of 320 mm ² / s at 25 ° C. is obtained. The branched siloxane polymer is modified with octyl groups at the free siloxane chain ends. Homogeneous mixtures are available with medium-viscosity silicone oils.

Comparative example

The procedure of Example 2 is repeated with the Modification that instead of the 1-octene 80 mmol C = C in the form of the 1,7-octadiene (C = C / SiH ratio = 1.2) is used.

It gets stronger under otherwise identical reaction conditions Viscosity increase a toluene insoluble solid receive. The product cannot be homogeneous with silicone oil be mixed.

Example 3

100 g of the hydrogen siloxane polymer prepared in Example 1 are mixed in a 100 ° C. mixture of 226 g of a monoallylic polyether with an average of 24 ethyleneoxy and 25 propyleneoxy groups of the formula CH ₂ = CH-CH ₂ -O- (CH ₂ CH ₂ O) ₂₄ - (CH ₂ CH ₂ CH ₂ O) ₂₅ -H and 0.3 g of the Karstedt catalyst solution described in Example 1 (Pt content = 1.0% by weight) are metered in. After a total reaction time of 3 hours, the active hydrogen (Si-bonded hydrogen) is completely converted. After cooling to 25 ° C, a clear, very viscous product with 18,400 mPa.s at 25 ° C is obtained. The free chain ends are modified with linear polyether chains.

Example 4

219 g of a linear, α, ω-dihydrogenpolydimethylsiloxane with a Si-bound hydrogen content of 0.014% by weight and a viscosity of 982 mPa.s at 25 ° C with 0.75 g Methyltrivinylsilan implemented. The one described in Example 1 Karstedt catalyst is at 25 ° C in an amount of 10 wt. ppm of platinum, based on siloxane, metered in after the Reaction mixture was diluted with half the amount of toluene. The solution is heated to 80 ° C, whereupon it thickens considerably. Then 0.9 g of 3-methylbut-1-in-3-ol are added, and one allows to react for 1 hour at 100 ° C.

After evaporating a sample of the solution in a bowl a highly branched siloxane polymer with a very high Viscosity, the chain ends of which have OH functions, receive. The polymer is again clearly soluble in toluene.

Claims (8)

1. The invention relates to branched organosiloxane (co) polymers containing structural elements of the formula

Y [-C _n H _2n - (R ₂ SiO) _m -A _p -R ₂ Si-G] _x (I)

in which
Y is a trivalent to ten-valent hydrocarbon radical with 1 to 25 carbon atoms per radical, which may contain one or more heteroatoms selected from the group consisting of oxygen, nitrogen and silicon atoms,
R can be the same or different and represents a monovalent optionally halogenated hydrocarbon radical having 1 to 18 carbon atoms per radical,
A represents a radical of the formula -R ₂ Si-R ² - (R ₂ SiO) _m -,
where R ^{2 is} a divalent hydrocarbon radical with 2 to 30 carbon atoms per radical, which can be interrupted by one or more separate oxygen atoms,
G denotes a monovalent radical of the formula -C _f H _2f-2k -Z or a divalent radical of the formula -C _n H _2n -, where the second bond is to a further radical Y,
Z is a monovalent hydrocarbon radical free from terminal aliphatic carbon-carbon multiple bonds, which is inert towards SiH groups in hydrosilylation reactions and can contain one or more heteroatoms selected from the group consisting of oxygen, nitrogen, boron, silicon and titanium, or with a monovalent polymer radical means more than 20 carbon atoms,
x is an integer from 3 to 10,
f is an integer from 2 to 12,
k is 0 or 1,
n is an integer from 2 to 12,
m is an integer of at least 1 and
p is 0 or an integer positive number,
with the proviso that the branched organosiloxane (co) polymers contain an average of at least one group Z. 2. Branched organosiloxane (co) polymers according to claim 1, characterized in that x is 3 or 4. 3. Branched organosiloxane (co) polymers according to claim 1 or 2, characterized in that p is 0. 4. Branched organosiloxane (co) polymers according to claim 1, 2 or 3, characterized in that the ratio of End groups Z to branch groups Y is 1.0 to 2.0. 5. A process for the preparation of the branched organosiloxane (co) polymers according to one of claims 1 to 4, characterized in that in a first step at least three compounds (1) having aliphatic double bonds of the formula
Y (CR ¹ = CH ₂ ) _x
wherein Y and x have the meaning given thereon in claim 1 and
R ^{1 represents} a hydrogen atom or an alkyl radical having 1 to 10 carbon atoms
with organopolysiloxanes (2) of the general formula
H (R ₂ SiO) _m -A _p -R ₂ SiH
where A, R, m and p have the meaning given for them in claim 1,
in the presence of catalysts which promote the attachment of Si-bonded hydrogen to aliphatic multiple bonds (3),
be implemented
and in a second step the branched intermediates (5) thus obtained containing Si-bonded hydrogen atoms with organic compounds (4) of the formula
C _f H _2f-2k-1 -Z
selected from the group of

if k = 0: H ₂ C = CR ³ -Z (4a)
and
if k = 1: R ⁴ C ~ CZ (4b)

wherein R ³ and R ^{4 have} the meaning of R ¹ , and
f, k and Z have the meaning given for this in claim 1,
in the presence of catalysts which promote the attachment of Si-bonded hydrogen to aliphatic multiple bonds (3),
be implemented. 6. The method according to claim 5, characterized in that as Compound (1) 1,2,4-trivinylcyclohexane is used. 7. The method according to claim 5 or 6, characterized in that that the organopolysiloxane (2) in the first process step is used in such quantities that the ratio of Si-bonded hydrogen in organopolysiloxane (2) aliphatic double bond in compound (1) at least Is 1.5. 8. The method according to claim 5, 6 or 7, characterized characterized in that the organic compound (4) in second process step used in such quantities is that the ratio of aliphatic double bond in (4a) or aliphatic triple bond in (4b) to Si bound hydrogen in the first step Intermediate (5) obtained is 1.05 to 1.5.