WO2016030185A1

WO2016030185A1 - Fast curing condensation rtv silicone rubber in bonding application

Info

Publication number: WO2016030185A1
Application number: PCT/EP2015/068549
Authority: WO
Inventors: Antonio TENG; Winter LI; Jack QIN; Vivi WU; Laura Zhang
Original assignee: Wacker Chemie Ag
Priority date: 2014-08-25
Filing date: 2015-08-12
Publication date: 2016-03-03
Also published as: CN105368062A

Abstract

The present invention relates to a fast curing condensation RTV silicone rubber composition for bonding, by using two organotin with a certain proportion as a catalyst, the silicone rubber composition shorten the curing time and the tack free time under the premise of ensuring preferable mechanical strength of the adhesive, with the characteristics of lower costs, improving yield and suitable for industrial production.

Description

Fast curing condensation RTV silicone rubber in bonding application

Technical Field

The present invention relates to a condensation room temperature vulcanizing silicone rubber (i.e. RTV) composition which can be used as an adhesive and a sealant and has the characteristics that the curing velocity is high, cured products have good bonding properties to base materials, the operation is simple and the composition is conductive for flow line production.

Background Art

It is known in the technical field that the composition of silicone rubber is formed by means of condensing and curing at room temperature, and the composition has been widely used in industry. The

polyorganosiloxane composition cured by condensation of hydroxyl groups and hydrolysable groups bonded to silicon atoms has excellent durability, high and low temperature resistance and strong cementitiousness , and thus can be used as a sealant and an adhesive in the aspects of architecture, electronics and consumer goods, etc.

In recent years, with the development of composite science, the condensed organic silicon adhesive has strong competitiveness in many fields, and can constantly meet and expand new demands.

Therefore, a condensed organic silicon adhesive which is low in production cost and simple in operation and facilitates

industrialized production is the direction of development. From the technical point of view, the difficult point of this technical development is to shorten the time when the silicone composition has high modulus housing with sufficient strength under the premise of ensuring preferable mechanical strength of the adhesive.

Summary of the Invention

It has been unexpectedly found by the present invention that the time for curing a condensed RTV composition to achieve the initial strength is short, and the condensed RTV composition has characteristics of reducing cost, improving productivity and being suitable for industrialized production.

The initial strength described herein refers to high-modulus housing with sufficient strength for forming a structural element, and this structural element will still be of the required configuration without permanent deformation even if being processed, packed and transported after a short period of time.

The present invention can be realized through the following technical solutions:

In the following content, unless otherwise specified, all numerals of fraction and percentage refer to weight (=wt%) .

An organosilicon composition curable fast at room temperature, comprising :

a) at least one polydiorganosiloxane of formula (I) :

wherein, R¹, R² and R³ are independently univalent hydrocarbon with 1 to 12 carbon atoms of a straight or branched chain; and group R⁴ is independently hydroxyl or alkoxyl, acetoxyl or ketoxime base with 1 to 13 carbon atoms,

The value of index p is 0, 1 or 2 ;

and index m may be the value which enables the

polydiorganosiloxane (I) to have the viscosity of 1,000 to 100,000 mPa · s at the temperature of 23 °C;

b) at least one crosslinking agent for the polydiorganosiloxane;

C) at least one catalyst for cross-linking reaction, wherein the catalyst is a composition of two organic tin compounds of formula _

(II) mixed in a ratio of 0.1-5:

(X)₂SnR⁵R⁶ (II)

wherein groups R⁵ and R⁶ are identical or different from each other and are substituted or unsubstituted univalent hydrocarbon with carbon number of CI -18, and X is halogen or monocarboxylic acid group with the structure of R⁷COO, wherein R⁷ is substituted or

unsubstituted univalent hydrocarbon with carbon number of Cl-18.

The above organosilicon composition curable fast at room temperature, further comprises as preferred embodiment at least one additional component selected from a filler, an adhesion promoter, a diluent or a plasticizer.

The organosilicon composition curable fast at room temperature in the present invention can be provided in the form of one component and two components .

Viscosities can be determined via measurement in a rotary viscometer in accordance with DIN EN ISO 3219. Unless otherwise stated, all of the viscosity data are valid at 23 °C and atmospheric pressure of 1013 mbar.

Compound a)

At least one polydiorganosiloxane of formula (I) in the present invention:

wherein, the value of index p is 0, 1 or 2 ;

and index m may be the value which enables the

polydiorganosiloxane (I) to have the viscosity of 10 to 500 , 000 mPa · s , preferably 100 to 150,000 mPa-s, particularly preferably 1,000 to 100,000 mPa-s, at the temperature of 23 °C;

The polydiorganosiloxane described in the present invention is preferably but not limited to hydroxy- terminated polysiloxane , is familiar hydroxyl silicone oil 107 with the viscosity of about 20,000 mPa-s at 23°C and is commercially available (e.g. WACKER⁹ Polymer FD 20) , and this polyorganosiloxane is prepared by a familiar method. For example, the content described in US4,962,152 is herein incorporated by reference.

The hydroxy-terminated polysiloxane described in the present invention is preferably hydroxy-terminated polydimethylsiloxane, which accounts for l0-50wt% of the total composition, preferably 15-40wt% . Compound b)

At least one cross - linking agent b) used for polydiorganosiloxane described in the present invention is preferably the silane of formula (III) :

(R⁸) _n-Si- (R⁹) ₄-_n (III)

wherein, group R⁸ is independently used as the group described above by R³, R⁹ independently represents the group described above by R⁴; index n is a value of 0 to 4 , and at least one of R⁸ and R⁹ is a reactive group (e.g. alkoxy, ketoxime group or acetoxyl group) with the a polydiorganosiloxane of formula (I) .

The silane applicable to formula (III) includes but not limited to tetramethoxysilane , tetraethoxysilane , tetrabutoxysilane , methyltrimethoxysilane, methyltriethoxysilane , vinyl

tri-methoxysilane , vinyltriethoxysilane , phenyltrimethoxysilane , phenyltriethoxysilane , 1 , 2 -bis (trimethoxysilyl) ethane,

1, 2 -bis (triethoxysilane) ethane,

4 , 4 , 6 , 6-tetraethoxy-5-methyl-3 , 7-dioxa-4 , 6-disilanonane, and part of hydrolyzed products of the organo-silicon compound, preferably the alkoxysilanes can be commercially available products or prepared by the known process in chemistry of silicones.

Consumption of the cross- linking agent described in the present invention accounts for 0.1-20wt% of the total composition, preferably l-15wt%. Compound c )

The catalyst described in the present invention is a combination of two kinds of dialkyl tin and the alkyls of the two kinds of dialkyl tin are different from each other. It is particularly preferably a corresponding carboxylate . It is particularly selected from dimethyltin dineodecanoate, dimethyltin di-2-ethylhexoate, dimethyltin dilaurate, hydroxyl (oleate) dimethyltin, dibutyltin bis (isooctylmaleate) , dibutyltin di-2-ethylhexoate, dibutyltin dilaurate, dibutyltin diacetate, dibutyltin dioctanoate, dibutyltin distearate , dibutyltin dimaleate, dioctyltin diacetate, dioctyltin dilaurate, di-n-octyltin di-2-ethylhexoate,

di-n-octyltin-bis-2 , 2-dimethyl octanoate, dioctyltin dimaleate, dioctyltin dioctanoate or the reaction products thereof obtained from reaction with silicate ester.

The catalyst described in the present invention is preferably a composition of the reaction product of dioctyltin dilaurate, silicate ester and dibutyltin diacetate, and the proportion of the reaction product of dioctyltin dilaurate, silicate ester and dibutyltin diacetate is 0.1-5, preferably 0.5-3 and particularly 1-3.

Based on the total composition, the consumption of the catalyst is 0.001-5wt%, preferably 0.01-3wt%.

Further compounds

The adhesion promoter described in the present invention is silane and/or hydrolysate with functional groups as an example, such as those with glycidyloxy, amino or methacryloxy . In addition, the silane with hydrolyzable group, Si-C bonded vinyl, acryloxy, methacryloxy, epoxy group, anhydride group, acidic group, ester group or ether group and part of or mixed hydrolyzates thereof can be used as the adhesion promoter.

The preferred adhesion promoter is amino-, acryloyl- and epoxy- functionalized silane with hydrolysable groups and/or partial hydrolysate thereof .

The adhesion promoter is more preferably selected from

N- [3- (trimethoxysilyl) propyl] -1, 2 -ethylenediamine ,

N-2 -aminoethyl -3 -aminopropyltrimethoxysilane ,

γ-aminopropyltriethoxysilane , aminopropyltrimethoxysilane,

N, N¹ -bis [3- (trimethoxysilyl) ropyl] ethylenediamine,

2,2- dimethyl - 1 -Aza- 2 - silacyclopentane - 1 - ethylamine ,

Bis ( γ- trimethoxysilylpropyl ) amine, γ-aminopropyl methyl

diethoxysilane , methyl aminopropyltrimethoxysilane,

4 -amino- 3 , 3 -dimethylbutyltrimethoxysilane ,

N-Ethyl-3-trimethoxysilyl-2-methylpropanamine or a hydrolysate mixture of one or more of them.

According to the present invention, the amount of the adhesion promoter is 0.1-20wt% of the total composition, preferably

0.3-15wt%.

According to the present invention, the examples of the diluent or the plasticizer are polydimethylsiloxane , alkoxy polysiloxane , alkoxy functional silicone resin or a mixture thereof.

According to the present invention, the amount of the diluent or the plasticizer is 0-80wt% of the total composition, preferably 10-50wt%.

According to the present invention, the filler includes but not limited to ground, settled and colloidal calcium carbonate treated with a compound of stearates or stearic acid; reinforced silicon dioxide, such as fumed silica, precipitated silica, silica gel and hydrophobic silica and silica gel; pulverized and ground quartz, aluminium oxide , aluminium hydroxide , titanium hydroxide , diatomite, iron oxide, carbon black, limestone, gypsum, silicon nitride , chalk, calcium silicate, zeolite, diatomite and so on.

According to the present invention, the amount of the filler is

5-70wt% of the total composition, preferably 15-50wt%.

The composition described in the present invention further comprises water and/or surfactant, the mixture of surfactant and water is a solution with a water content of 10-90wt%, the surfactant is nonionic surfactant, which can be selected from a mixture of one or more of polyoxypropylene castorate, ethoxylated castorate, polyoxyethylene stearate, stearic polyoxyethylene ether, oleic acid ethoxylate, copolymer of ethylene oxide (EO) and propylene oxide (PO) , preferably one or more of a mixture of castorate

polyoxypropylene, polyoxyethylene stearate and stearic

polyoxyethylene ether; the mixture of surfactant and water is preferably one or more of polyoxypropylene castorate,

polyoxyethylene stearate and stearic polyoxyethylene ether with the water content of 40-80wt%. Based on the total composition, the amount of the water and/or surfactant is 0-10wt%, preferably 0.1-5wt%.

According to one embodiment of the present invention, the organosilicon composition curable fast at room temperature is obtained by using a "double-component" composition. In the double-component system, the first component comprises the polydiorganosiloxane of the present application and a matter for promoting deep curing, and the second component comprises the above-mentioned cross-linking agent and catalyst of the present application. The adhesion promoter, filler, diluent and plasticizer can be added into the first component or the second component or the both simultaneously. "Components" of the double-component composition are stored in separated packages to prevent early curing . One embodiment of the present invention as double-component composition includes but is not limited to the following modes:

The organosilicon composition curable fast at room temperature comprises component A and component B:

component A:

hydroxy-terminated polysiloxane ,

filler,

adhesion promoter (content can be 0) ,

diluent, plasticizer, water and/or surfactant;

component B :

cross-linking agent,

adhesion promoter,

filler,

diluent, plasticizer

and catalyst.

The components A and B are mixed uniformly in a ratio of (7-13) to 1 and the components A and B can be mixed by stirring, kneading or rod pressing, but particularly preferably mixed by a static mixer .

The present invention provides an organosilicon composition, which has good cohesiveness to base materials, can be fast cured at room temperature and is simple in operation, safe, high in controllability and high in production efficiency, so the organosilicon composition is suitable for industrialized

production . The organosilicon composition curable fast at room temperature in the present invention can be used as an adhesive or a sealant in various different applications.

Examples: Detailed Description of the Invention

In the following embodiments, unless indicated otherwise, the following embodiments are implemented in the ambient atmosphere of about 0. IMPa and environment temperature of about 23°C or at the temperature produced by mixing reactants at environment temperature without additional heating or cooling.

Test Method

Test Method of Cure Time and Tack Free Time

The cure time referred by the present invention is the time for converting a soft viscous silicone material into solid with initial strength and elasticity. Under the premise that initial strength is fixed, the cure time is determined by a standard method for testing shear force with GB/T 7124-2008.

A finger touches the surface of an adhesive tape, the viscosity disappears, and the non-sticking time is the tack free time. The tack free time is tested according to an architecture sealing material test method of GB/T 13477-1992.

Bearing Capacity Test

Components A and B are coated between an ABS plastic frame (not processed by plasma) and a color microcrystal panel (containing an ink coating) after being mixed uniformly in the required ratio, the materials for the contact surface include ABS plastic and the ink coating, the length of the panel is 35cm, the width of the panel is 33cm, the width of silica gel is about 4 mm and the thickness is 0.8 -lmm when the silica gel is spread uniformly, and whether the bonding surface can bear force of 8kg or not is tested after lOmin.

Embodiment

Preparation Method of Component A

mixing 20.0 parts of hydroxyl-terminated polydimethylsiloxane (available from WACKER⁸ Polymer FD 20), 20.0 parts of calcium carbonate and 0.9 part of methyloxirane and

2 , 2-dimethyl-l-aza-2-silacyclopentane-l-ethylamine (CAS :

618914-51-5) uniformly, stirring uniformly, adding 9.5 parts of lime stone, adding 4.7 parts of ethoxy functionalized silicone resin, 9.1 parts of polydimethylsiloxane (available from WACKER^S AK 100) and 0.5 part of water after stirring uniformly, and stirring uniformly under vacuum.

Preparation Method of Component putting 370.0 parts of polydimethyl siloxane fluids (viscosity is 20000 mPa-s at 25°C) , 203.1 parts of linear polydimethyl siloxane fluid (viscosity is 95-105 mPa · s at 25°C, available from Wacker Chemie , WACKER° AK 100) and 32.1 parts of carbon black into a planetary mixer, mixing at 200rpm for 5min, adding another 32.1 parts of carbon black, mixing at 200rpm for 5min, and scraping the container wall while stirring. Then, mixing under vacuum at 200rpm for another lOmin.

Adding a mixture of 203.5 parts of 1, 2 -bis (triethoxysilyl) ethane (available from Wacker Chemie, WACKER⁹ Vernetzer ET 13) , 28.0 parts of tetraethoxysilane (available from Wacker Chemie, WACKER^® TES 28) , 18.0 parts of tetraethoxysilane and ethanol (available from Wacker Chemie, WACKER^® Silicate TES 40 WN) , mixing under vacuum at 400rpm for 15min. Finally adding reactants of 101.5 parts of

N- 3 - ( trimethoxysilylpropyl) ropyl - 1 , 2 -ethylenediamine (available from Wacker Chemie, GENIOSIL^® GF 91) , 13 parts of

bis ( lauroyloxy) dioctyltin and 6.5 parts of reaction product of tetraethyl orthosilicate and dibutyltin diacetate, and mixing under vacuum at 400rpm for 15 min. Preparation Method of Component B2

putting 173.0 parts of polydimethyl siloxane fluid (viscosity is 20000 mPa-s at 25°C) , 95.0 parts of linear polydimethyl siloxane fluid (viscosity is 95-105 mPa- s at 25°C, available from Wacker Chemie , WACKER^S AK 100) and 15.0 parts of carbon black into a planetary mixer, mixing at 200rpm for 5min, adding another 15.0 parts of carbon black, mixing at 200rpm for 5min, and scraping the container wall while stirring. Then, mixing under vacuum at 200rpm for another lOmin.

Adding 95.3 parts of 1 , 2 -bis (triethoxysilyl) ethane (available from Wacker Chemie, WACKER° Vernetzer ET 13) , and mixing under vacuum at 400rpm for 15 min. Finally adding reactants of 47.6 parts of N-3- (trimethoxysilylpropyl) ropyl-1, 2-ethylenediamine (available from Wacker Chemie, GENIOSIl⁹ GF 91) , 3.0 parts of reaction product of tetraethoxy-silicone and dibutyltin diacetate, and mixing under vacuum at 400rpm for 15 min.

The preparation method of B3 and B4 is the same as that of B2 , wherein the catalysts are respectively reactants of 6.0 parts and 9.0 parts of reaction product of tetraethoxy- silicone and dibutyltin diacetate .

The preparation method of B5 and B6 is the same as that of B2 , wherein the catalysts are respectively 6.0 parts and 9.0 parts of dioctyltindilaurate .

Embodiments 1-5

Component A and component B2-6 are mixed uniformly in a ratio of 10: 1.

Embodiment 6

Component A and component B are mixed uniformly in a ratio of 10 : 1.

The test results of cure time and tack free time are shown in Table 1 below.

Table 1 Test Results

After coated by the composition of embodiment 6 for 10 minutes, the bonded plastic frame and microcrystal panel can bear the force of 8KG therebetween.

It is stored with the relative air humidity (r. h.) of 50% at 23 °C for 24 hours after curing. The mechanical properties are measured according to DIN 53504-85S1 (tensile strength, elongation at break) and DIN 53505 (Shore A hardness) . The results are listed in table 2 below.

Table 2: Mechanical Properties after Curing

It can be seen from the above results that, under the premise that the superior mechanical strength is ensured, the composition can greatly improve catalytic effect based on the same consumption of the catalyst.

Claims

1. An organosilicon composition curable fast at room temperature , comprising :

a) at least one polydiorganosiloxane of formula (I) :

wherein, R¹, R² and R³ are independently univalent hydrocarbyl with 1 to 12 carbon atoms of a straight or branched chain; and group R⁴ is independently hydroxyl or alkoxyl, acetoxyl group or ketoxime base each having 1 to 13 carbon atoms,

the value of index p is 0, 1 or 2 ; and index m may be the value which enables the polydiorganosiloxane (I) to have the viscosity of 1,000 to 100,000 mPa-s at the temperature of 23°C

b) at least one crosslinking agent for the polydiorganosiloxane; C) at least one catalyst for cross-linking reaction, wherein the catalyst is a composition of two organic tin compounds of formula (II) mixed in a ratio of 0.1-5:

(X) ₂Sn R⁵R⁶ (II)

wherein groups R⁵ and R⁶ are identical or different from each other and are substituted or unsubstituted univalent hydrocarbyl with carbon number of Cl-18, and X is halogen or monocarboxylic acid group with the structure of R⁷COO, wherein R⁷ is substituted or unsubstituted univalent hydrocarbyl with carbon number of Cl-18.

2. The organosilicon composition curable fast at room temperature of claim 1, further comprising at least one additional component selected from a filler, an adhesion promoter, a diluent or a plasticizer .

3. The organosilicon composition curable fast at room temperature of claim 1 or 2 , wherein the cross - linking agent b) is silane of formula ( II) :

(R⁸) _n-Si- (R⁹) 4-n (ID

wherein, group R⁸ is independently used as the group described above by R³ , R⁹ independently represents the group described above by R⁴; index n is a value of 0 to 4 , and at least one of R⁸ and R⁹ is a reactive group (e.g. alkoxy, ketoxime group or acetoxyl group) with the polydiorganosiloxane of formula (I) . The cross-linking agent is preferably dealcoholization methyl triethoxyl silane, vinyltriethoxysilane , 1, 2-bis- (triethoxysilane) ethane, 4,4,6,6 - tetraethoxy-5-methyl-3 , 7-dioxa-4 , 6 -disilanonane or a mixture thereof .

4. The organosilicon composition curable fast at room temperature of claim 2 or 3 , wherein the adhesion promoter is selected from N- [3- (trimethoxysilyl) propyl- 1, 2-ethylenediamine,

N-2 -aminoethyl - 3 -aminopropyltrimethoxysilane ,

γ-aminopropyltriethoxysilane, phenylaminopropyltrimethoxysilane , Ν,Ν' -bis [3- (trimethoxysilyl) propyl] ethylenediamine , 2,

2 -dimethyl-1-aza-2-silacyclopentane-l-ethylamine,

bis- (γ-trimethoxysilylpropyl) amine,

γ-aminopropylmethyldiethoxysilane or a hydrolysis mixture of one or more of them.

5. The organosilicon composition curable fast at room temperature of claim 2 or 3 or 4 , wherein the diluent or the plasticizer is selected from dimethyl silicone polymer, alkoxy polysiloxane , alkoxy functional silicone resin or a mixture thereof.

6. The organosilicon composition curable fast at room temperature according to any one of claims 1-5, wherein the silicone composition is a double-component composition and further comprises water and/or surfactant, the surfactant is the mixture of one or more copolymers selected from polyoxypropylene castorate, ethoxylated castorate, polyoxyethylene stearate, stearyl alcohol polyoxyethylene ether, oleic acid ethoxylate or ethylene oxide (EO) and propylene oxide (PO) , preferably the mixture of one or more of polyoxypropylene castorate, polyoxyethylene stearate and stearyl alcohol

polyoxyethylene ether.

7. The organosilicon composition curable fast at room temperature according to any one of claims 1-6, wherein the catalyst c) is selected from dimethyltin or dibutyltin or dioctyltin, preferably dibutyltin and dioctyltin, and dicarboxyl dioctyltin and dicarboxyl dibutyltin are especially preferred.

8. The organosilicon composition curable fast at room temperature according to claim 7, wherein the ratio of the dicarboxyl dioctyltin to the dicarboxyl dibutyltin is 0.1-5, preferably 0.5-3, and particularly preferably 1-3.

9. The organosilicon composition curable fast at room temperature according to claim 7 or 8 , wherein the dicarboxyl dioctyltin is selected from dibutyltin diacetate, dibutyltin dilaurate, dibutyltin dioctoate or the reaction product thereof with silicate, preferably dibutyltin dilaurate; the dicarboxy dibutyltin is selected from dibutyltin diacetate, dibutyltin dilaurate, dibutyltin dioctoate, or the reaction product thereof with the silicate, preferably dibutyltin dioctoate or the reaction product thereof with the silicate.

10. The organosilicon composition curable fast at room temperature according to claim 9, wherein the proportion of the dioctyltin dilaurate to the reaction product of silicate ester and dibutyltin diacetate is 0.1-5, preferably 0.5-3, particularly preferably 1-3.