DE4014882A1 - Polyfunctional poly-organo-siloxane(s) - by low-temp. nitration of poly-methyl-phenyl-siloxane(s), and conversion of nitro gps. into other functional gp(s) - Google Patents

Abstract

Polyfunctional polyoganosilanes are of formula (I) (where n = 10-500; R = Me, with ratio Me:Ph gps. = (2.2:1)-(3.5:1); X = NO2, NH2, OH, Hal, CN, NCO, (meth)acrylate gp. or maleimide gp. of formula (II) (with R1 = H, 1-4C alkyl or Ph). Also claimed is a process for the prodn. of (I) by low-temp. nitration of the corresp. unsubstd. polymer (with X = H) with a mixt. of Ac2O and concentrated HNO3 to give a poly(nitrophenyl)siloxane (I, X = nitro). Other functional gps. are introduced by redn. of the nitro polymer (pref. with Fe/AcOH in EtOH) to give the corresp. amine, and conversion of the amine gps. into OH, Hal, CN or NCO, or into maleimide gps. by reaction with opt. substd. maleic anhydride. USE/ADVANTAGE - (I) are used for prodn. of polymers with liq. crystalline side chains (claimed). Enables prodn. of polymers with the usual desirable properties of silicones (thermal stability, elasticity, low water absorption, good electrical properties, etc.) combined with functionality distributed along the whole polymer chain, which can be used to introduce mesogenic gps., etc.. Other applications include photosensitive resists, photo-crosslinkable coatings, etc..

Description

The invention relates to new polyfunctional polyorganosiloxanes as well as their manufacture and use.

Polyorganosiloxanes such as poly (methylsiloxanes) and poly (methyl phenylsiloxanes), show - due to their chemical structure - special combinations of properties, such as chemical-thermal Stability, UV stability, flexibility, elasticity and flui dity, even at low temperatures, as well as small surfaces voltage, low water absorption, good dielectric properties and high corona resistance. Poly (methylphenylsiloxane) - Structures, for example, are therefore fundamentally In Interest in the construction of new types of polymer, especially with for interesting properties of electrical engineering. So the like polymers for the production of passivation layers for electronic components and as polymer networks with good Low temperature properties are used or to solve haf problems in the production of molded articles from reak tion resins and for the production of polymers with liquid crystals stallinen properties are used.

Such polymers can be implemented by introducing them ter functional groups in polyorganosiloxanes, for example have poly (methylphenylsiloxane) structures, whereby the properties of the polysiloxanes, for example in technical main area of application in the field of silicone chewing Tschuke, can be changed. So the polyorganosil oxanes, also known as silicones, by the introduction of olefinically unsaturated groups such as vinyl and Allyl groups can be made radically crosslinkable. By one Leading maleimide groups can be photostructurable  Developing polymers based on organosilicon, in particular are particularly suitable for component technology. Furthermore could by introducing β-cyanoethylmethyl siloxy or γ-cyano propyl-methyl-siloxy units in poly (dimethylsiloxanes) Resistance to swelling of silicone rubbers can be improved, and by saponification of corresponding cyano groups in silicone oils their lubricity could be increased.

It is also known to modify the properties or ganic polymer in their network to include siloxane sequences to build. For example, copolymers are used in resin chemistry by combining organosiloxane components with hydroxy epoxy compounds prepared and prepared in polyimide resin for semiconductor coatings - to improve the Moisture resistance - siloxane structures installed (see EP-OS 02 88 209).

With a few exceptions, such as those in DE-OS 32 35 663 are described where by cohydrolysis and coequili Bration of dichloro-dialkylsilanes and dichloro-alkyl-malein imidosilanes maleinimide-functional photocrosslinkable Polyorga nosiloxanes are produced, functional groups in Polyorganosiloxanes only introduced α, ω constantly, namely via Si-OH end groups (see for example EP-OS 00 54 426). A such a procedure limits the variation of the radio group density from the start.

The object of the invention is to provide polyorganosiloxanes len, which not only have α, ω-functional groups, but where the chemical functionality across the entire poly Merkette is distributed.

According to the invention, this will be followed by polyorganosiloxanes achieved the general formula:

the following applies:
n = 10 to 500, preferably 30 to 150,
R = CH ₃ , the ratio of methyl groups to phenyl groups being between 2.2: 1 and 3.5: 1,
X = NO ₂ , NH ₂ , OH, halogen, CN, NCO, an acrylate or methacrylic lat residue or a maleimide residue with the following structure:

with R ¹ = H, C ₁ - to C ₄ -alkyl or phenyl.

The polyorganosiloxanes according to the invention have a high Density of functional groups, the chemical radio tionality can be specifically integrated across the entire polymer chain can. The new polyorganosiloxanes are suitable, for example for the production of photoresists and photocrosslinkable deck layers, moreover, these connections can be compo nenten for reactive resins, for example for the production of Polyurethanes and polyureas, as well as cross-linking compos nents of epoxy resins or for passivation layers be used. In particular, the invention ß polyfunctional polyorganosiloxanes - by coupling mesogenic groups - for the production of liquid crystalline Side chain polymer suitable.

The new polyfunctional polyorganosiloxanes are invented manufactured in accordance with the invention in such a way that poly (phenylsiloxanes)  the structure

where n and R have the meaning given above, by Low temperature nitriding, generally below 0 ° C, with a mixture of acetic anhydride and concentrate ter nitric acid, generally fuming nitric acid, in Poly (nitrophenylsiloxanes) are transferred.

The poly (methylphenylsiloxanes) used as starting materials can, for example, from organohalosilanes by cohydroly se and co-equilibration are made; the manufacture of the Organohalosilanes can according to Rochow or by means of a Grignard synthesis according to Dilthey and Kipping. Furthermore can in the inventive method of commercial Po ly (methylphenylsiloxanes) with known methyl / phenyl group Ratio can be assumed. The methyl / phenyl group ver Ratio generally moves within the manufacturing process bandwidths due to technical reasons.

In the production of the polyorganosiloxanes according to the invention can mix nitric acid with different acetic acid hydride / nitric acid ratio are used, whereby the Nitro group concentration varies and can be controlled specifically can. For example, when using nitriding acid mixtures from 100 parts by weight of nitric acid and 100 parts by weight parts of acetic anhydride, each for 100 parts by weight of poly (me thylphenylsiloxane), between the nitric acid concentration and the nitro group content of the reaction product is a linear Be drawing. It is therefore possible to determine the functional group density of to be determined in advance, d. H. selectively set in  simple way.

The poly (ni trophenylsiloxanes) - by reducing the aromatic Nitro groups - are converted into poly (aminophenylsiloxanes). The reduction takes place in a manner known per se, at for example using hydrazine hydrate and Raney nickel (in Di oxane), using iron powder and hydrochloric acid (in propanol), using amalgamated aluminum chips (in propanol) or electroche mix (in an ether / propanol / water mixture). Preferably is the reduction of the nitro groups with iron powder and Glacial acetic acid carried out in ethanol; this creates poly (amino phenylsiloxanes) of high quality in 85 to 90% yield. The Amino group concentration can be easily over the degree of nitration and can be specifically set or controlled.

The poly (aminophenylsiloxanes) according to the invention can in can be modified in many ways. The amino groups of these Connections can - in a manner known per se - in particular can be converted into the following groups: OH, halogen, CN and NCO. For example, this happens as follows:

• - Diazotization with nitrous acid and subsequent hydrolysis gives OH;
• - by diazotization and subsequent Sandmeyer reaction (Um settlement of the benzene diazonium salts with halides or cyanide) halogen groups or the cyano group are introduced;
• - The reaction with phosgene leads to the NCO group.

The amino group can also advantageously be converted into a maleimido group, ie into a functional group which can be crosslinked by free radicals or photochemically; the conversion takes place by reacting the poly (aminophenylsiloxanes) with - if necessary substituted - maleic anhydride. Via OH-functional compounds, acrylate or methacrylate residues can also be built into the polyorganosiloxanes by known methods, ie the groups -O-CO-CH = CH ₂ and -O-CO-C (CH ₃ ) = CH _2nd There is also the possibility of adding glycol monoesters of acrylic or methacrylic acid to NCO-functional compounds. The amino groups - or also OH or NCO groups - are particularly advantageous for introducing mesogenic groups. These groups give the polyorganosiloxanes according to the invention the character of liquid-crystalline side chain polymers.

The invention is intended to be described in more detail by means of exemplary embodiments are explained.

Example 1: Preparation of poly (methylnitrophenylsiloxane)

In one with a stirrer, internal thermometer and gas discharge pipe provided 500 ml three-necked flask are 100 g commercially available Poly (methylphenylsiloxane) with a medium methyl / phenyl Ratio of approx. 2.6: 1 dissolved in 100 g acetic anhydride, and the solution is then cooled to -25 ° C. Then who depending on the desired degree of nitration, between 25 and 175 g of fuming nitric acid were added dropwise, with stirring the internal temperature must not rise above -20 ° C (duration: between 30 and 90 min). This is followed by 1 h at -20 ° C stirred and then the reaction mixture to room temperature brought. Then the reaction mixture becomes 500 ml of ice water poured water and treated twice with 250 ml of ether. The combined ethereal phases are washed twice with water neutralized with a sodium hydrogen carbonate solution and dried over sodium sulfate. After removing the Ether is the poly (methylnitrophenylsiloxane) in the form of a yellow-brown oil obtained (yield: about 95%).

NMR and viscosity measurements show that the nitro groups can be set specifically. When nitriding it followed para- and ortho-substitution of phenyl  leftovers. With increasing reaction time, however, a meta- Substitution takes place.

Example 2: Preparation of poly (methylaminophenylsiloxane)

50 g of the poly (methylnitrophenyl prepared according to Example 1 siloxane) are dissolved in 168 g of glacial acetic acid. After adding 1 l of ethanol and 80 g of iron powder is refluxed for 8 h is heating. After cooling to room temperature, the reaction mixture poured into 2 l of ice water and treated twice with ether delt. The combined ethereal phases are washed twice with egg ner sodium bicarbonate solution and then washed with water and then dried over sodium sulfate. After the Ent 37.5 g (corresponding to 86%) of poly (me thylaminophenylsiloxane) with an amine value of 5.7%.

Example 3: Preparation of poly (methylmaleinimidophenylsiloxane)

20 g of the poly (methylaminophenyl) prepared according to Example 2 siloxane) are heated to boiling in 50 ml of dichloromethane, then a solution of 10 g of maleic acid is added with stirring hydride dropwise in 50 ml dichloromethane. After 30 minutes it will Dichloromethane removed, and the reaction mixture 60 g Acetic anhydride and 8 g of sodium acetate added. On finally heated to 80 ° C for 1 h and then the mixture to 200 ml Water was added and the mixture was stirred at room temperature for 24 h. That included product obtained is taken up in ether, washed with water and dried over sodium sulfate. After removing the Ether is the poly (methylmaleinimidophenylsiloxane) in 75% obtained yield; it falls depending on the type of used Poly (methylaminophenylsiloxane) or poly (methylnitrophenyl siloxane), as an oil or in the form of an amorphous powder.

Claims (7)

1. Polyfunctional polyorganosiloxanes of the general formula: the following applies:
n = 10 to 500,
R = CH ₃ , the ratio of methyl groups to phenyl groups being between 2.2: 1 and 3.5: 1,
X = NO ₂ , NH ₂ , OH, halogen, CN, NCO, an acrylate or methacrylic lat residue or a maleimide residue with the following structure: with R ¹ = H, C ₁ - to C ₄ -alkyl or phenyl. 2. A process for the preparation of polyfunctional polyorganosiloxanes according to claim 1, characterized in that poly (phenylsiloxanes) of the structure where n and R have the meaning given in claim 1, are converted into poly (ni trophenylsiloxanes) by nitration at low temperature with a mixture of acetic anhydride and concentrated nitric acid. 3. The method according to claim 2, characterized records that the poly (nitrophenylsiloxanes) in known way by reduction in poly (aminophenylsil oxanes) are transferred. 4. The method according to claim 3, characterized records that the reduction using iron powder and Glacial acetic acid is carried out in ethanol. 5. The method according to claim 3 or 4, characterized ge indicates that the amino group in itself be is known to be transferred to one of the following groups: OH, halogen, CN or NCO. 6. The method according to claim 3 or 4, characterized ge indicates that the amino group by reaction with optionally substituted maleic anhydride in a Maleimido group is converted. 7. Use of the polyfunctional polyorganosiloxanes according to An saying 1 for the production of liquid crystalline side chains polymers.