CH649772A5 - LIGHT CROSSLINKABLE POLYSILOXANES, METHOD FOR THE PRODUCTION AND THEIR USE. - Google Patents

Description

The invention relates to new light-crosslinkable polysiloxanes, processes for their preparation and their use.

(IV) 65 DE-AS 2 557 940 describes phenylmaleimide

group-containing polysiloxanes and their use for the production of photocured films and coatings. Similar polysiloxanes with aro- in the 2- or 3-position

3rd

649772

Maleic or heterocyclically substituted maleimide groups and their use for the production of printing plates are described in Japanese Patent Laid-Open Nos. 77-106 864 and 77-105 002.

The invention relates to new light-crosslinkable polysiloxanes with high photosensitivity, which have an average molecular weight of 750 to 1,500,000 and which consist of 10 to 100 mol% repeating structural elements of the formula I.

Ï *

-Si-O-

I.

a

• m *

r / \

: co

(i)

average molecular weight of 750 to 120,000, which consist of 15 to 100 mol% of repeating structural elements of the formula I and 0 to 85 mol% of repeating structural elements of the formula II, where A - (CH2) P- represents-5. Particularly preferred are light-crosslinkable polysiloxanes with an average molecular weight of 750 to 100,000, which consist of 25 to 96 mol% of repeating structural elements of the formula I and 4 to 75 mol% of repeating structural elements of the formula II, in which A - (CH2) 2- or - (CH2) 3-, Ri is hydrogen or methyl and R2, R3 and R4 are each methyl.

The light-crosslinkable polysiloxanes according to the invention can be prepared in a manner known per se, e.g. by either

15

a) a compound of formula III

Ri

I.

2o Cl-Si-Cl

I.

r2

(III)

and from 0 to 90 mol% of recurring structural elements of the formula II

R.

with 10 to 100 mol% of a compound of formula IV

Si-O

I.

R2

(IV)

exist, with an average of at least three structural elements of the formula I being present per molecule, and in which 35

A represents a radical -CPH: P- with p = 2 to 10, the main chain of which can be interrupted by -O-, -NH- or -NH-Ci-t-alkyl (CH3) 3Si-0,

Ri is hydrogen, methyl, phenyl or vinyl,

R: methyl or phenyl and

Rj and Ri independently of one another represent C1-4-alkyl or together trimethylene or tetramethylene optionally substituted by a methyl group.

In the various structural elements of the formulas I and II, the A, Ri, R2, R3 and R4 can each represent the same or different radicals as defined. They preferably each mean the same radicals as defined.

Residues represented by A -CPH2P- can be straight-chain or branched. Examples of radicals A as defined are:

- (CH:) p- with p = 2-10, -CH2CH2OCH2CH2 - CH2CH2NH-CH2CH2-, -CH2CH2NHCH2CH2NHCH2CH2- ~ CH2CH2NH (CH2>, -CH2CH: N (CH3) CH2CH2-,

-CH2CH (CH3) -, -CH2CH2CH (CH3) -, - CH2CH2CH (CH3)

CH2CH2- and -CH2CH (CH3) CH (CH3) CH2-, A preferably represents - (CH2) p- with p = 2-10 and in particular - (CH2) 2- or - (CH2> -.

Ri is preferably hydrogen or methyl. R2 is preferably methyl. Alkyl groups R3 and R4 can be straight-chain or branched, but are preferably straight-chain.

R3 and R4 each preferably represent methyl. X-S i-R,

The average molecular weights are determined in a manner known per se by means of light scattering or by 65

Vapor pressure osmometry (weight or number average)

determined.

Light-crosslinkable polysiloxanes are preferably cohydrolyzed and then equilibrated, or b) a poly-H-siloxane of the formula V

Ri '

I.

Si-O

I.

R2

SÌ (CH3) 3

(V)

with 10 to 100 mol% of a compound of formula VI

V / co '

I!

r '\ or

(vi)

implements, wherein A, R2, R3 and R4 the under the formulas I and

50 II have the meaning given, Ai is a radical -CPH2P-i- with p = 2-10, the main chain of which can be interrupted by -O-, -NH- or -NH-C1-4-alkyl and Ri 'is hydrogen, methyl or is phenyl, but must be hydrogen in at least 10 mol% of the structural elements of the formula V.

55 Polysiloxanes according to the invention can also be obtained by using a cyclotetrasiloxane of the formula VIIa

\

X I

R2

Vìi /!

X

'V.

R-S.-X 0

(Vlla),

649772

4th

wherein at least one X is a group

/ ° N / * 3 / •

-A-N ^ Ii

C (/

and the others a group

C0 / R3

R represents -Si-R 1 \ z or Ri, optionally together with a cyclotetrasiloxane of the formula VIIIb

V

o / fNo / 2 \.

x * R2? Sl "Rl (Vllb)

° v °

Si '

1

R2

equilibrated, where A, Ri, R2, R3 and R4 have the meaning given above.

According to a further process, polysiloxanes according to the invention can also be prepared by using a polysiloxane which consists of 10 to 100 mol% recurring structural door elements of the formula Villa

R2

I.

--Si-O -

I.

A-NHa a) oligomeric or polymeric linear or cyclic polysiloxanes are formed. The cohydrolysis is expediently carried out in an aqueous or preferably in an aqueous-organic medium. Suitable solvents are e.g. alipha-5 thical ether, especially dialkyl ether, such as diethyl ether, methyl ethyl ether and diisopropyl ether, and 1,2-dimethoxyethane. In the subsequent equilibration, the mixtures of linear and cyclic siloxanes with different molecular weights are converted into mixtures of linear siloxanes with higher and more uniform average molecular weights by redistribution of the Si-10 O bonds. These equilibration reactions can be catalyzed thermally or by acids or bases. Preference is given to equilibration in the presence of an acid catalyst, particularly conc. Sulfuric acid or acidic earth, and optionally in the presence of an inert organic solvent.

The addition of the maleimides of the formula VI to the poly-H-siloxanes of the formula V is advantageously carried out in the presence of an inert organic solvent and a catalyst. Suitable solvents are e.g. aromatic hydrocarbons such as benzene, toluene and xylenes; 1,2-dimethoxyethane and diethylene glycol dimethyl and diethyl ether.

25 Precious metal catalysts, in particular platinum, palladium and rhodium catalysts, are generally used as catalysts, e.g. Platinum on carbon, FhPtCld, palladium acetate and rhodium phosphine complexes. HaPtCla is preferably used as catalyst. The reaction is advantageously carried out at elevated temperature.

The reaction of the amino group-containing polysiloxanes with the anhydrides of the formula IX is advantageously carried out in the presence of inert organic solvents, such as toluene, xylenes, N, N-dimethylformamide or N, N-dime-35 thylacetamide, at elevated temperature and / or with the addition of a dehydrating agent , e.g. Acetic anhydride.

The polysiloxanes according to the invention can be used to produce light-crosslinked polysiloxanes 40 and can be used in the presence of up to 30 mol%, preferably up to 15 mol%, of a crosslinking agent of the formula X

(Villa)

and 0 to 90 mol% of recurring structural elements of the formula VIIIb

C0 \ A

C (/

(X)

50

Ri t

-si-o 4-I

Ra consists of 10 to 100 mol% of an anhydride of the formula R3N / C \

1 * 0

r / \ /

implements. In the formulas Vlla, Vllb, Villa, and Vlllb, A, Ri, R2, R3 and R4 have the meaning given above.

In the cohydrolysis of the compounds of the formula III with the compounds of the formula IV according to the process variant, where the A, Ri, R2, R3 and R4 have the meaning given under the formulas I and II and z is an integer from 1 to (VIIIb) 20,000 means to be networked under the influence of light.

The Ri and Ri in the recurring structures can each represent the same or different residues. The R 1 and R 2 preferably have the same meaning in each structural element. With regard to preferred meanings of A, Ri, R2, R3 and R4, what has been said above applies. Compounds of the formula X are preferred in which A - (CH2) P- with p = 2-10 and z 60 is an integer from 1 to 20. Particularly preferred (IX) are compounds of the formula X in which A - (CH2) 2- or - (CH2) 3-, R 1 is hydrogen or methyl, R 2, R 3 and R 4 are each methyl and z is an integer from 1 to 20.

The compounds of formula X can be e.g. be made by

A) a compound of the formula X with z = at least 1 with a cyclotetrasiloxane of the formula VIIIb

5

649772

\ L / Sk

0 R 0/2 \.

Rr ^ R2 v i °

i

R2

equilibrated,

B) a compound of formula XI

(Vllb)

H

ri '

I.

Si-O

I.

R2

Ri '

I.

-SiH

I.

R2

(XI)

in a molar ratio of 1: 2 with a compound of formula VI

V /

(VI)

implements

C) a compound of formula XII

(XII)

hydrolyzed to the corresponding disiloxane and optionally equilibrated with suitable cyclosiloxanes, or in a molar ratio of 2: 1 with a compound of formula XIII

Compounds of the formula VI to the compounds of the formula XI can be carried out under analogous reaction conditions as described above for the addition to the poly-H-siloxanes of the formula V. The condensation of the siloxane diol of formula XIII with the chlorosilyl compound of formula XII is advantageously carried out in the presence of a base, e.g. Triethylamine or pyridine. The reaction of the diamine of the formula XIV with the anhydride of the formula IX is carried out as described above for the reaction of the polysiloxanes containing amino groups with the anhydrides of the formula IX.

The starting compounds of the formulas III to IX and XI to XIV are known or can be prepared by methods known per se. With regard to the production of the silanes and siloxanes to be used, reference is made, for example, to Noll: Chemie und Technologie from Silicone, Verlag Chemie GmbH, Weinheim, 1968.

For the crosslinking of the polysiloxanes according to the invention, optionally in a mixture with a crosslinking agent of the formula X, any desired light sources can be used, e.g. Sunlight, carbon arc, xenon lamps, metal halide lamps and especially high pressure mercury lamps. The exposure is optionally carried out with the addition of photosensitizers, e.g. Benzophenone 25 or thioxanthone derivatives.

The crosslinked products obtainable with the polysiloxanes according to the invention are notable for high corona resistance and good oxygen permeability. The light-crosslinkable polysiloxanes 30 according to the invention are suitable, for example, for the production of photoresists or high-temperature-resistant insulating materials and, above all, for the production of moldings, such as seals, coatings and coatings on various materials, such as glass, ceramics, plastics, e.g. Polyesters and 35 polyimides, cellulose materials and above all metals such as aluminum and copper. Depending on the density of crosslinking, they result in soft, elastic to tough solid layers, which are particularly distinguished by good adhesion to metals such as aluminum and copper.

40

example 1

R.

I.

Ri

45

HO-

HO-J-Si-Of-Si-OH

I.

R2 Z-1R2

implements, or

D) a compound of formula XIV

(XIII)

50

ri

H2N-A 4-si-o-l-si-A-NH2 I

R2 z R.2

Ri

(XIV)

-Si-O-

rf-

rà3y

XCH 1 ^

n: m

: 3: 1

in a molar ratio of 1: 2 with an anhydride of the formula IX. Z, A, Ri, R2, R3 and R4 have the meaning given above, Ai is a radical -CPH2P-i- with p = 2-10, the main chain of which is defined by -O-, -NH- or -NH-C1- 1-alkyl may be interrupted, and Ri 'means methyl or phenyl.

The conditions given above apply to the equilibration of the compounds of the formula VIIIb. The addition of the

A mixture of 11.2 g (0.04 mol) of N- (3-methyldichlorosilylpropyl) -2,3-dimethylmaleinimide, 16.5 g (0.128 mol) of 60 dimethyldichlorosilane and 100 ml of diethyl ether is added to 250 ml with vigorous stirring Dropped in ice water. After the hydrolysis has ended, the ether phase is separated off, washed neutral with distilled water, dried with anhydrous sodium sulfate and concentrated to about 20 ml. To this 65 solution, 3.5 ml of conc. H2SO4 and shake for 24 hours at room temperature. After dilution with 30 ml of diethyl ether, the mixture is washed until neutral, dried with sodium sulfate and finally in a high vacuum from the solution

649772 6

medium exempt. Yield 14.5 g (77% of theory); Viscosity The N- (3-methyldichloro-

[t |]: 4.6 ml g- '(measured at 25 ° C in toluene); Nitrogen content silylpropyl) -2,3-dimethylmaleinimide can as in DE-OS

3.25%. 2 934 550.

Example 2

By equilibration of 1 part of 1,2,3,4-tetramethyl-20-dimethylmaleinimide (0.07 mol), 0.3 ml of HzPtCk solution cyclotetrasiloxane with 3 parts of 1,1,2,2,3,3,4,4 -Octamethyl- (0.05 m in 2-propanol) and 50 ml of toluene were added dropwise. After cyclotetrasiloxane with hexamethyl-disiloxane as a chain-terminated addition, the mixture is refluxed for a further 60 minutes, a poly-H-siloxane with the following properties is heated and then produced with the addition of 1 g of activated carbon: inherent viscosity: 0.887 Pa s / 25 ° C. [r |] = 16.7 ml / g, and 2 g filter earth filtered. After removing all

H-Si group content: 3.4 meq / g. 25 parts (most recently in a high vacuum) gives 28.6 g

To a solution of 20.0 g (corresponding to 0.068 Val Si-H) of a viscous oil (91% of theory); [t |] = 26.3 ml / g in toluene of the polysiloxane thus prepared in 100 ml of toluene at 25 ° C .; Nitrogen content 2.76%; average molecule-90 ° C under nitrogen a mixture of 11.6 g of N-allyl-2,3-lar weight (determined by light scattering): ~ 70,000.

Example 3

Analogously to Example 2, 6.66 g of the poly-H-siloxane (corresponding to 0.0225 Val Si-H) are reacted with 2.0 g (0.014 mol) of N-vinyl-2,3-dimethylmaleinimide and worked up as described in Example 2 . Yield 7.7 g (89% of theory); Nitrogen content 1.95%; average molecular weight: 70,000 (determined by light scattering); H-Si content 1.6 m equivalent / g.

Example 4

(CH3) 3Sij

? H3

-O-Si

? H2

CH-I 2

? H2

0 = '

\ /

C <

■ = 0

\

CH "

-0-Si (CH3) 3

ti

7

649772

Analogous to the procedure described in Example 2, 10 g (corresponding to 0.156 equivalent Si-H) of a commercial polymethylhydrogensiloxane (Silgel W®, Wacker-Chemie, Burghausen, FRG) are mixed with 25.7 g (0.156 mol) N-allyl- 2,3-Dimethylmaleinimid brought to reaction. After the exothermic reaction has subsided, the mixture is heated under reflux for a further 5 hours. The polysiloxane obtained is after removal of the catalyst by precipitation of the

Reaction solution isolated in 11 n-hexane. The viscous product is dried at 80 ° C and 0.0133 Pa for 24 hours. Yield: 32 g (92% of theory); Molecular weight: ~ 10 300 (determined by vapor pressure osmometry in CHCb);

Nitrogen content: 6% silicon content: 13.8%

calculated degree of substitution 96%.

CH ^ / C0.

II «

ch37 \ a

Example 5

CH CH I J I

C0X / CH3

J- (CH -), - SÌ-0-Si- (CH «II

2 3 »I 2 3 \ / \

CH "CH CO CH"

To a mixture of 50 g (0.3 mol) of N-allyl-2,3-dimethyl-maleinimide and 0.8 ml of 0.05 m H2PtCl6 solution in 2-propanol, add 20 under nitrogen at 60 ° C. 15 g (0.15 mol) of tetramethyldisiloxane were added dropwise. The temperature of the reaction mixture temporarily rises to 140 ° C and is then kept at 110 ° C for 1 hour. The oil obtained crystallizes after distillation in a high vacuum. 53.2 g (0.11 mol = 76% of theory) of 1,3-bis- [3- (2,3-20 dimethylmaleinimidyl) propylj-1,1,3,3-tetramethyl-diso are obtained -loxane; Bp 220-222 ° C / 0.2 mbar; Mp 55-57 ° C, nitrogen content 6.03%.

Example 6

CH ^ .CO.

./

c / x

CO

<\ / CH3

«Vj-Si

A mixture of 4.65 g (0.01 mole) 1,3-bis- [3- (2,3-dimethylmethylimidyl) propyl] -1,1,3,3-tetramethyl-disiloxane, 14.83 g (0.05 mol) of octamethyl-cyclotetrasiloxane, 30 ml of dimethoxyethane and 3 ml of conc. H2SO4 is shaken at room temperature for 24 hours. The oil obtained is diluted with 100 ml of diethyl ether, washed neutral with water and freed from the solvent after drying over sodium sulfate. After filtration through a G3 glass frit, the product is dried to constant weight at 100 ° C and 0.2 mbar. Yield 17.7 g; Intrinsic viscosity: 0.0363 Pa s. [r |] = 2.2 ml g_1 (at 25 ° C in toluene). M (average molecular weight, determined by vapor pressure osmometry in CHCb) 1874-2096; z = 19-21; Nitrogen content 1.57%.

Example 7

Photochemical crosslinking of a poly-dimethylsiloxane with 3- (2,3-dimethylmaleinimidyl) propyl groups.

A 20% solution of the polysiloxane prepared according to Example 2 in toluene is spun onto roughened aluminum sheet according to the principle of the paint spinner on a rotating disc. The sheet coated in this way is then dried at 90 ° C. for 15 minutes. The liquid layer is cured by exposure to a high-pressure mercury lamp (700 W) for 5 minutes. A clear, firm coating is obtained. At non-exposed areas, the still liquid polysiloxane can be removed with organic solvents such as trichlorethylene, acetone, tetrahydrofuran or cyclohexane, and the metal can be etched with HCI / H2O2 / H2O without destroying the coating.

Example 8-10

Analogous to procedure 35 described in Example 7, the polysiloxanes prepared according to Examples 2 and 3 are crosslinked photochemically, in some cases using benzophenone as a sensitizer. The irradiation is carried out with a metal halide lamp (5000 W). The results are shown in the table.

40

Polysiloxane

Benzophenone

Exposure time

Coating according to example 2

5% by weight

2 minutes firm, good adhesion according to example 3

0

3.5 minutes firm, swellable according to example 3

5% by weight

2 minutes firm, good adhesion

Example 11

Analogous to the procedure described in Example 7, a mixture of 10 g of the polysiloxane prepared according to Example 4 and 0.2 g of 3-chlorothioxanthone-1-carboxylic acid n-octyl ester is applied to copper foil and exposed. An adherent, mechanically strong coating is obtained.

55

Example 12

Analogously to Example 7, a mixture of 10 g of the polysiloxane prepared according to Example 2 and 2 g of the polysiloxane produced according to Example 6 is applied to copper sheet

60 and exposed. A firm, very elastic coating is obtained. The copper metal can be etched in the unexposed areas after development with trichlorethylene using a FeCb solution.

B

Claims (8)

649772 2nd PATENT CLAIMS 1. Light-crosslinkable polysiloxanes with an average molecular weight of 750 to 1,500,000, which consist of 10 to 100 mol% recurring structural elements of the formula I (I) and from 0 to 90 mol% of recurring structural elements of the formula II Ri I. Si-0 + I. R2 (II) Ri I. Cl-Si-Cl I. R2 with 10 to 100 mol% of a compound of formula IV cohydrolized and then equilibrated, where A, R1, R2, R3 and R4 have the meaning given in claim 1. 5. A process for the preparation of crosslinkable poly-s siloxanes according to claim 1, characterized in that a poly-H-siloxane of the formula V io (CH3> Si-0 Ri ' -Si-O- R2 Si (CH3> (V) with 10 to 100 mol% of a compound of formula VI 15 20 R4 * / \ (VI) exist, where at least three structural elements of the formula I are present on average per molecule, and in which A represents a radical -CPH2P- with p = 2 to 10, the main chain of which may be interrupted by -O-, -NH- or -NH-Ci-4-alkyl, Ri is hydrogen, methyl, phenyl or vinyl, R2 is methyl or phenyl and R3 and R.4 independently of one another represent Ci-4-alkyl or together trimethylene or tetramethylene optionally substituted by a methyl group. 2. Polysiloxanes according to Claim 1 with an average molecular weight of 750 to 120,000, which consist of 15 to 100 mol% of repeating structural elements of the formula I and 0 to 85 mol% of repeating structural elements of the formula II, and in which A - (CH2) P- represents, in which p is a number from 2-10. 3. Polysiloxanes according to claim 1 with an average molecular weight of 750 to 100,000, which consist of 25 to 96 mol% repeating structural elements of the formula I and 4 to 75 mol% repeating structural elements of the formula II, wherein A - (CH2) 2- or - (CH2) 3-, Ri represent hydrogen or methyl and R2, R3 and R4 each represent methyl. 4. A process for the preparation of light-crosslinkable polysiloxanes according to claim 1, characterized in that a compound of formula III implemented, wherein R2, R3 and R4 have the meaning given in claim 1, A1 represents a radical -CPH2P-i - with p = 2-10, the main chain of which is -O-, -NH- or -NH-C1-4- 25 alkyl can be interrupted and Ri 'is hydrogen, methyl or phenyl, but must be hydrogen in at least 10 mol% of the structural elements of the formula V. 6. Use of polysiloxanes according to claim 1 for the preparation of light-crosslinked polysiloxanes, characterized 39 in that they are present in the presence of up to 30 mol% of a crosslinking agent of the formula X. V / ° ycas / R3 i-A- ^ C </ \ (X) (III) 40 in which A represents a radical -CPH2P- with p = 2 to 10, the main chain of which may be interrupted by -O-, -NH- or -NH-C1-4-alkyl, Ri is hydrogen, methyl, phenyl or vinyl, R2 is methyl or phenyl, 45 R3 and R4 independently of one another are C1-4-alkyl or together trimethylene or tetramethylene optionally substituted by a methyl group and z are an integer from 1 to 20,000, are crosslinked under the action of light. s # 7. Use according to claim 6, wherein A in formula X is - (CH2) P- with p = 2-10 and z is an integer from 1 to 20. 8. Use according to claim 6, wherein A in formula X - (CH2) 2- or - (CH2) 3-, Ri hydrogen or methyl, R2, R3 ss and R4 each represent methyl and z is an integer from 1-20. 9. Use of crosslinkable polysiloxanes according to claim 1 for the production of moldings, coatings and coatings. 60 V / c ii rA Ç1 J-A-Si-Cl K