WO2006087079A1

WO2006087079A1 - Compositions cured by michael addition reaction

Info

Publication number: WO2006087079A1
Application number: PCT/EP2006/000689
Authority: WO
Inventors: Christoph Briehn; Richard Weidner
Original assignee: Consortium für elektrochemische Industrie GmbH
Priority date: 2005-02-17
Filing date: 2006-01-26
Publication date: 2006-08-24
Also published as: DE102005007320A1

Abstract

The invention relates to compositions Z which may be cured by addition reaction, comprising a component A, with at least one activated methylene, amino, carbinol or thio function as Michael donor and a component B with at least one group of general formula (II) =Si-CR<SUP>2</SUP> <SUB>2</SUB>-

Description

Michael addition reaction curable compositions

The invention relates to compositions which can be cured by a Michael-type addition reaction and to their use.

The reaction referred to in the literature as Michael addition of activated methylene compounds, e.g. Malonic esters, cyanoacetic esters or amines, the so-called Michael donors, with electron-poor alkenes, such. α, β-unsaturated

Compounds, the so-called Michael acceptors, can be exploited for the crosslinking of correspondingly functionalized silanes or organopolysiloxanes.

The advantage of such curable compositions according to a Michael-type reaction is that neither high-cost noble metal catalysts nor toxicologically questionable tin catalysts are necessary for the curing. In addition, during this addition hardening no products are split off, which could lead to a shrinkage of the hardening product or to an environmental impact.

U.S. 4,698,406 discloses Michael addition curable organopolysiloxane blends. These mixtures contain, as crosslinkable components, an aminoalkyl- and an acryl-functional organopolysiloxane. Acrylic-functional components are understood below to mean compounds having acrylic, methacrylic, acrylamide and methacrylamide groups. As the Michael acceptor component, i.a. describes an organopolysiloxane whose acrylic functions L correspond to the general formula I,

s Si (CRi ₂ ) _X -L (I), via a propyl group (x = 3) to a silyl group ≡Si- des

Organopolysiloxane are linked. In this case, R ^{1 is} hydrogen or a monovalent organic radical.

EP 0 780 422 and EP 0 818 497 describe, by Michael addition, curable aqueous organopolysiloxane emulsions which are obtainable by mixing a Michael acceptor-functionalized organopolysiloxane, an emulsifier and a Michael donor-functionalized hardener in water. In particular, organopolysiloxanes which carry acrylic functions corresponding to the general formula I where x = 3 are mentioned as the Michael acceptor component.

Acrylic functional organopolysiloxanes are i.a. by

Hydrosilylation of SiH-functional organopolysiloxanes with vinyl-functional acrylates or by reacting acrylic-functional chloro- or alkoxysilanes accessible with organopolysiloxanes. In particular, the use of acrylic-functional chloro- or alkoxysilanes allows the targeted chain and terminal incorporation of the acrylic functions in organopolysiloxanes and oxides, such. Colloidal or fumed silica, in high yields. In this case, di-functionalization can already take place during the synthesis (for example by cohydrolysis or the sol-gel process) or subsequently (for example by equilibration or termination of silanol-functional compounds). For example, US Pat. No. 5,292,849 and DE 102 19 734 describe the functionalization of silanol-functional linear and branched organopolysiloxanes with various (meth) acryl-functional alkoxysilanes. The

Acrylic functionalization of pyrogenic and colloidal silica is described inter alia in US 2003/0194549 A and US 4491508 A and is, for example, by reacting the oxides achieved with 3-methacrylatopropyltrimethoxysilane.

The acrylic-functional organopolysiloxanes described in the prior art as Michael acceptors, their acrylic groups corresponding to the general formula I where x = 3 via a

Propylgruppe are separated from Organopolysiloxanrest show limited to activated methylene groups, alkylamines or amino-functional siloxanes reactivity, i. the expected Michael adducts are not formed or only in very low yield. In a binder system which utilizes the Michael reaction for curing, the low reactivity of these acrylic functional organopolysiloxanes used as Michael acceptors, whose acrylic groups corresponding to general formula I where x = 3 are separated from the organopolysiloxane moiety by a propyl group, can be in an insufficient network density and thus result in a property profile that is deficient for an application.

Curable organopolysiloxane mixtures would be advantageous in which the Michael acceptor contains units of the general formula I and thereby has a high reactivity towards Michael donors, so that a sufficient network density of the composition obtainable after curing is ensured for an application.

The invention relates to addition-crosslinkable compositions Z, the one

Component A, which carries at least one activated methylene group, amino, carbinol or thiol as Michael donor, and a

Component B, the at least one radical of the general formula II ≡Si - CR ² ₂ -ADC (II),

wherein R ^{2 is} hydrogen or hydrocarbon radical having 1 to 12

Carbon atoms whose carbon chain may be interrupted by non-adjacent oxygen, sulfur, or NR ³ groups,

R ^{3 is} hydrogen or hydrocarbon radical having 1 to 12 carbon atoms,

A oxygen, sulfur, = NR ³ or = N- (DC),

D is a carbonyl group and

C is an ethylenically unsaturated group.

Component B, which carries at least one functional group of the general formula II and whose functional group ADC is only separated by a methylene group from the silyl group ≡Si, shows a significantly higher reactivity towards the component A than a component whose Michael acceptor a longer alkyl chain (general formula I: - (CR ^) _x "it ^m x ≥ 2) is connected to the silyl group.

As component A, all amino- or carbinol- or thiol-functional monomers, oligomers or polymers

Compounds are used which have free NH, OH or SH functions. Examples of suitable oligomeric and polymeric components A are common amine hardeners which are used, for example, for crosslinking epoxy resins, e.g. Diethylenetriamine, triethylenetetramine,

Tetraethylenepentamine, aminoethylpiperazine, polyethylenepolyamine, metaphenylenediamine, diaminodiphenylsulfone, Diethyl and polyamides of type Versamid ^® (Henkel) or Ancamide ^® (Air Products and Chemicals, Inc.). In a preferred embodiment aminofunktioneile silanes such as trimethoxysilane be Ethylendiaminopropyl or hydrolysis products thereof, amino functional organopolysiloxanes such as Wacker ^® HP 2000 (Wacker-Chemie) and siliconates, such as are described for example in EP 0780422 A2, are used. Furthermore, as component A carbinol functional parts monomeric, oligomeric and polymeric compounds such as acrylic polyols, polyester polyols, polyether polyols, epoxy polyols,

Polyurethane polyols and carbinol functional organopolysiloxanes are used;

Further suitable as component A are monomeric, oligomeric and polymeric compounds which carry activated methylene groups. This can be, for example acetoacetoxy polymers as described in Farbe & Lack, 110th year, 2/2004, pp 22-24 ^■, or polymers as activated

Methylene groups units of the formulas -CO-CHR ^U -CO-, NC-CHR ^U -CO-, -CO-CHR ^U -NC> 2, = CHR ^U -CN, where R ^{u is} a monovalent organic radical or hydrogen. Also correspondingly functionalized particles, such as, for example, amino-functional pyrogenic, precipitated or colloidal silica or metal oxides, for example aluminum oxide, can be used as component A.

Component B has radicals of the general formula II which have an electron-deficient ethylenically unsaturated group C as Michael acceptor.

Preferably, the hydrocarbon radicals R ^ i to 4 carbon atoms. Preferably, the

Hydrocarbon radicals R ³ 1 to 4 carbon atoms.

As component B are monomeric, oligomeric or polymeric Compounds or particulate structures are used which have at least one functional group of the general formula II.

A-D-C of the general formula II preferably has the

Meanings Acrylato, Methacrylato, Acrylamido, Methacrylamido on.

Preferred as component B are organopolysiloxanes of the general formula III,

(SiO _4/2) k (R ⁴ Siθ3 / 2) m ^ ⁴ 2SiOi / 2) q [O _u / 2 (R ⁵ O) _V - _U R ⁴ _(3-V) SiCr ADC ² _2] _s [O ₁ Z ₂ H] _t (III ⁾ ,

used, where

R ^ hydrogen or a monovalent optionally substituted by - CO, -NCO, -NR ^X 2 '-COOH, -halogen, -P (O) (OR ^X ) ₂ , -EPOX, -SH, -OH or -CONR ^X 2 substituted Si-C-bonded C ₁ . C2o hydrocarbon radical or C ₁ -C ₁ S-. Hydrocarbonoxy, in each of which one or more, non-adjacent methylene units by groups -0-, -CO-, -COO-, -0C0- or -OCOO-, -S- ^' or -NR ^X - may be replaced and in which one or more mutually non-adjacent methine units can be replaced by groups -N =, -N = N- or -P =,

R ⁵ is an optionally cyano or halogen-substituted C _1- C ₁ 5.Kohlenwasserstoffrest,

R ^{x is} hydrogen or a C ₁ -C _1Q- hydrocarbon radical optionally substituted by -CN or halogen, s are values of at least 1, v are values of 1, 2 or 3, u values of 1, 2 or 3, where u must be less than or equal to v and

R ^, A, D, C have the above meanings.

Preferably, the hydrocarbon radicals R ^{4 have} 1 to 6 carbon atoms. Particularly preferred are methyl and ethyl radicals. Preferably, the hydrocarbon radicals R ^ have 1 to 4 carbon atoms. Particularly preferred are methyl and ethyl radicals.

Furthermore, as component B metal oxide and metal mixed oxide particles (eg aluminum oxides such as corundum, mixed aluminum oxides with other metals and / or silicon, titanium oxides, zirconium oxides, iron oxides), silica particles (eg colloidal silica, fumed silica, precipitated silica) can be used having on their surface over functions of general formula II, via which a reaction with the functional groups of component A can take place. These particles which can be used as component B preferably have an average diameter of less than 1 mm, more preferably less than 1000 nm, the particle size being determined by transmission electron microscopy.

In a preferred embodiment of the invention, the particles which can be used as component B consist of pyrogenic silicic acid functionalized with radicals of the general formula II. In a further preferred embodiment of the invention, correspondingly functionalized colloidal silicon or metal oxides are used, which are preferably present as a dispersion of the corresponding submicron oxide particles in an aqueous or organic solvent. The oxides of the metals aluminum, titanium, Zirconium, tantalum, tungsten, hafnium and tin are used.

For the compositions Z, one or more different components A and B can be used. Thus, for example, compositions Z are the subject of the invention, which contain, as component A, an amine-functional siloxane and, as components B, a methacryl-functional siloxane and a methacryl-functional silicic acid.

The acrylic functional organopolysiloxanes and oxides are prepared by customary processes known to the person skilled in the art, for example cohydrolysis, equilibration and termination of silanol-functional compounds. Si-OH-, Me-OH- (Me = metal), Si-O-Si, Si-O-Me-functional compounds such as linear or branched organopolysiloxanes, organopolysiloxane resins, silicon dioxide, titanium dioxide are preferred for the preparation of the Michael acceptor , Alumina or zirconia - optionally in the presence of suitable catalysts - with acrylic functional. Alkoxy or chlorosilanes reacted. Examples of suitable alkoxy- and chlorosilanes are acrylatimethyl-trimethoxysilane, acrylatomethyl-methyldimethoxysilane, acrylatomethyl-dimethylmethoxysilane, acrylatomethyl-triethoxysilane, acrylatomethyl-methyldiethoxysilane, acrylatomethyl-dimethylethoxysilane, acrylatomethyl-trichlorosilane, acrylatomethyl-methyldichlorosilane, acrylatorethyl-dimethylchlorosilane, methacrylatomethyltrimethoxysilane, methacrylatomethyl- methyldimethoxysilane, methacrylatomethyldimethylmethoxysilane, methacrylatomethyltriethoxysilane, methacrylatomethylmethyldiethoxysilane, methacrylatomethyldimethylethoxysilane, methacrylatomethyltrichlorosilane, methacrylatomethylmethyldichlorosilane, methacrylatomethyldimethylchlorosilane, acrylamidomethyltrimethoxysilane, Acrylamidomethyl-methyldimethoxysilane, acrylamidomethyl-dimethylmethoxysilane, acrylamidomethyl-triethoxysilane, acrylamidomethyl-methyldiethoxysilane, acrylamidomethyl-dimethylethoxysilane, acrylamidomethyl-trichlorosilane, acrylamidomethyl-methyldichlorosilane, acrylamidomethyl-dimethylchlorosilane, methacrylamidomethyl-trimethoxysilane, methacrylamidomethyl-methyldimethoxysilane, methacrylamidomethyl-dimethylmethoxysilane,

Methacrylamidomethyl-triethoxysilane, methacrylamidomethyl-methyldiethoxysilane, methacrylamidomethyl-dimethylethoxysilane, methacrylamidomethyl-trichlorosilane, methacrylamidomethyl-methyldichlorosilane and methacrylamidomethyl-dimethylchlorosilane.

The preparation of the compositions 2 is carried out by mixing the components A and B in the presence or

Absence of a solvent or water. If component A is present, for example, as an alcoholic solution, then component B can be mixed into this solution and the composition Z obtained can be applied directly. The solvent is in this case before or during the

Hardening process evaporated or remains as a plasticizer in the cured material. Alternatively, the solvent after mixing e.g. be removed by distillation before the composition is cured. Preferably, at least one of the components A or B is present below the curing temperature as a liquid. In this case, a solid component may be dissolved or dispersed in the liquid component. In a preferred composition, components A and / or B are in the form of an aqueous emulsion or dispersion.

As dispersants for the components A and B all commonly used emulsifiers and / or protective colloids can be used. Examples of protective colloids are polyvinyl alcohols, cellulose derivatives or vinylpyrrolidone-containing polymers. Common emulsifiers are, for example, ethoxylated alcohols and phenols (alkyl radical C ₄ -C ₁ S / EO grade 3-100), alkali metal and ammonium salts of alkyl sulfates (C ₃ -C 18), sulfuric acid and phosphoric acid esters and alkyl sulfonates. Particularly preferred are sulfosuccinic and alkali alkyl sulfates and polyvinyl alcohols. Of course, several protective colloids and / or emulsifiers can be used as a mixture.

The emulsions containing the components A and / or B are prepared in a conventional manner known to the person skilled in the art. To avoid a premature reaction between the components A and B, is preferably one of

Components A or B in the emulsified phase, while the other component is in the continuous phase - Alternatively, Component A and Component B are dispersed separately and then combined.

The properties of the cured materials can be adjusted almost arbitrarily via the structure of the components A and B used as well as the number of functional groups. Thus, a composition Z containing an α, ω-amino functional linear organopolysiloxane as component A and an organopolysiloxane resin having a low density of acrylic functions as component B provides an elastomer after cure. By contrast, the use of a component B having a high acrylic density results in a thermoset material after curing.

The ratio of components A and B to one another is preferably selected such that the molar ratio of Michael donors to radicals of the general formula II is 2: 1 to 1: 2 is. Preferably, a ratio of 1.5: 1 to 1: 1.5 is selected. In particular, an excess of an amine-functional compound used as component A should be avoided in order to prevent yellowing of the cured materials.

For the curing of the compositions Z are preferably used for this 5 min - 48 h at 0-180 ⁰ C heated. Particularly preferably, the curing is carried out for 20 min - 24 hours at 20-120 ⁰ C. For compositions Z, in which the components A and / or B are present in aqueous emulsion, the curing takes place after evaporation of the aqueous solvent. The evaporation of the water can be carried out under atmospheric pressure or reduced pressure and / or with heating.

In order to accelerate the cure, typical Michael addition-catalyzing compounds may be added to Composition Z. In particular for compositions Z, which contain as component A an activated methylene compound, carbinol- or thiol-functional compounds, find tertiary

Amines, such as 1, 5-diazabicyclo [4.3.0 ¹ ' ^s ] non-5-ene (DBN), 1,8-

Diazabicyclo [5.4.0 ¹ ' ⁷ ] undec-7-ene (DBU), alkali metal hydroxides, alkali metal alkoxides, quaternary ammonium salts, quaternary phosphonium salts, tertiary sulfonium salts, guanidines, amidines and tertiary phosphines. The catalysts are preferably added in 0.1 to 10 wt .-%; most preferably, the amounts of catalyst added are less than 5% by weight.

The compositions Z can also contain common solvents as well as the additives and additives customary in formulations. Amongst others, leveling agents, surface-active substances, adhesion promoters and light stabilizers should be mentioned such as UV absorbers and / or radical scavengers such as 3,5-di-tert-butyl-4-hydroxytoluene (BHT), thixotropic agents and other solids and fillers. To produce the respective desired property profiles of both the compositions Z and the cured compositions, such additives are preferred. This applies in particular if the compositions Z are to be used as coatings. Likewise, these formulations may also contain dyes and / or pigments.

The compositions Z are preferably used as adhesives and sealants and as coating agents for preferably metal, wood, paper, glass, textile and plastic substrates. A preferred application is the use of the compositions Z for the encapsulation of electronic components.

All symbols of the above formulas have their meanings independently of each other. In all formulas, the silicon atom is tetravalent.

Examples

The organopolysiloxane used HP 2000 MQ resin powder 803 TF and Silres ^® SIO are from Wacker-Chemie GmbH _/ Munich, available. Tonsil ^® Optimum FF is a product of southern chemistry.

Unless otherwise indicated, all amounts and percentages are by weight in the following examples, all pressures are 0.10 MPa (abs.) And all temperatures are 20 ^° C.

Example 1:

Reaction of α-methacrylatomethyl-dimethylmethoxysilane with n-butylamine To a solution of 6.40 g (33.9 mmol) of α-methacrylatomethyl-dimethylmethoxysilane in 10 ml of toluene are added 2.49 g (33.9 mmol) of n-butylamine and 0.06 g of 3,5-di-tert-butylamine. butyl-4-hydroxytoluene (BHT) and the mixture heated to 80 ⁰ C for 3 h. In the ¹ H-NMR spectrum, a silane conversion of 40% was determined.

Comparative Example 1 (not according to the invention):

Reaction of γ-methacrylatopropyl-dimethylmethoxysilane with π-butylamine

To a solution of 0.54 g (2.50 mmol) of γ-methacrylatopropyl-dimethylmethoxysilane in 1 ml of toluene are added 0.18 g (2.50 mmol) of n-butylamine and 0.005 g of BHT and the mixture is heated to 80 for 3 h ⁰ C heated. In the ¹ H-NMR spectrum, a silane conversion of <5% was determined.

Example 2:

Reaction of an α, ω-acrylatomethyldimethylsilyl-Functional Polydimethylsiloxane with n-Butylamine

To a solution of 5.00 g of an α, ω-acrylatomethyldimethylsilyl-functional polydimethylsiloxane prepared by conventional methods (as described for example in DE 102 19 734) with a Mn of 1200 g / mol in 10 ml of toluene are 0.61 g (8 , 33 mmol) of n-butylamine and 0.05 g of BHT and the mixture was heated to 120 ⁰ C for 3 h. In the ¹ H-NMR spectrum, a quantitative conversion of the acrylate groups was determined.

Example 3:

Preparation of an α-methacrylatomethyl-dimethylsilyl-Functional Organopolysiloxane Resin

610 To a solution of 25.0 g of methyl resin Silres ^® in 25 g of toluene, 1.25 g α-methacrylatomethyldimethylmethoxysilane and, 1.25 g Tonsil ^® Optimum FF and the mixture for 6 h heated to 80 ⁰ C. The mixture is then filtered and the filtrate is evaporated under reduced pressure. This gives a colorless powder with a methacrylic content of 0.25 mmol / g.

Example 4:

Preparation of a curable composition

5.00 g of a 51% strength toluene solution of the α-methacrylatomethyl-dimethylsilyl-functional organopolysiloxane resin described in Example 3 (methacrylic content: 0.13 mmol / g solution) are reacted with 0.39 g of an α, ω-aminopropyl-dimethylsilyl-functional Polydimethylsiloxans mixed with a Mn of 1200 g / mol and placed in an aluminum pan. The mixture is heated at 120 ^° C. for 1 h. This gives a transparent, hard material which has a slight swelling when stored in toluene.

Comparative Example 2 (not according to the invention):

5.00 g of a 51% strength toluene solution of the α-methacrylatomethyl-dimethylsilyl-functional organopolysiloxane resin described in Example 3 are placed in an aluminum pan. After heating for 1 h at 120 ^σ C to obtain a highly viscous oil, which dissolves when stored in toluene.

Example 5:

Preparation of a curable composition

5.00 g of a 56% strength toluene solution of an α-methacrylatomethyl-dimethylsilyl-functional organopolysiloxane resin (methacrylic content: 0.89 mmol / g solution), which was prepared by cohydrolysis of tetraethoxysilane, hexamethyldisiloxane and α-methacrylatomethyl-dimethylmethoxysilane according to the conventional process, are mixed with 1.65 g of the amino-functional organopolysiloxane resin HP 2000 and placed in an aluminum pan. The mixture is stored for 1 h at 120 ⁰ C. This gives a transparent, hard Material that has a slight swelling when stored in toluene.

^■ Comparative Example 3 (not according to the invention): According to Example 5, 5.00 g of the non-functionalized organopolysiloxane resin MQ 803 TF with 1.65 g of an amino-functional organopolysiloxane resin mixed HP 2000, and stored for 1 hour at 120 ⁰ C. This gives a cloudy, highly viscous oil, which is covered by a thin skin. The product dissolves when stored in toluene.

Claims

claims

1. Addition-crosslinkable compositions Z, which carries a component A, which carries at least one activated methylene group, amino, carbinol or thiol function as Michael donor, and a

Component B, the at least one radical of the general formula II

≡Si-CR ² ₂ ~ ADC (II),

wherein R ^{2 is} hydrogen or hydrocarbon radical having 1 to 12

R 1 is hydrogen or hydrocarbon radical having 1 to 12 carbon atoms,

A is oxygen, sulfur, = NR ³ or = N- (DC), D is a carbonyl group and

C is an ethylenically unsaturated group.

2. Addition-crosslinkable compositions Z according to claim 1, in which A-D-C has the meanings of acrylato, methacrylato, acrylamido or methacrylamido.

3. Addition-crosslinkable compositions Z according to claim 1 or 2, in which as component B organopolysiloxanes of the general formula III,

(SiO 4/2) k (R ⁴ SiO 3/2) _m (R ⁴ ₂ SiOi / ₂ ) q [O _u / 2 (R ⁵ O) _v ] _u R ⁴ ₍ 3_v ₎

SiCR ² ₂ -ADC] _s [O ₁ Z ₂ H] _t (III), be used, where

R ^{4 is} hydrogen or a monovalent optionally substituted by -CO, -NCO, -NR ^X ₂ / -COOH, -halogen, -P (O) (OR ^x ) ₂ , -epoxy, -SH, -OH or -CONR ^X 2 substituted Si-C-bound C] __ C2o-

Hydrocarbon radical or C ₁ _C _] _5-hydrocarbonoxy radical, in each of which one or more, mutually non-adjacent methylene units represented by groups -O-, -CO-, -

COO, -OCO or -Oc00-, -S- or -NR ^X - may be replaced and in which one or more mutually non-adjacent methine units are replaced by groups -N =, -N = N- or -P = can,

R ^ is an optionally cyano- or halogen-substituted C ^ _ ^C 15 hydrocarbon radical, R ^{x is} hydrogen or an optionally substituted by -CN or halogen C ^ _C ^ g -Kohlenwasserstσffrest, s values of at least 1, v values of 1, 2 or 3 , u are values of 1, 2 or 3, where u must be less than or equal to v and

R ^, A, D, C have the above meanings.

4. Addition-crosslinkable compositions Z according to claim 1 to 3, in which metal oxide or metal mixed oxide particles are used as component B, which have on their surface over functions of the general formula II.

5. Addition-crosslinkable compositions Z according to claims 1 to 4, in which components A which carry at least one activated methylene group, amino, carbinol or thiol function as Michael donor are used as component A.

6. Addition-crosslinkable compositions Z according to claim 1 to 5, in which one or both components A, B are present as aqueous emulsion or dispersion.

7. Addition-crosslinkable compositions Z according to claim 1 to 6, in which the ratio of the components A and B to each other is selected so that the molar ratio of Michael donors to radicals of the general formula II is 2: 1 to 1: 2.

8. Use of the addition-crosslinkable compositions Z according to claim 1 to 7 as adhesives and sealants, as a coating composition and for the encapsulation of electronic components.