Curable silicone compositions containing additives

Abstract

The invention relates to curable compositions based on polyorganosiloxanes with special silicon-containing terminal groups, a curing catalyst, and a polymer having at least one silane-functional group. The invention also relates to adhesive, sealant, and/or coating materials comprising said composition and the use of said composition.

Claims

1. A curable composition comprising (A) at least one polyorganosiloxane containing at least one terminal group of the formula (I):
Si(R.sup.1).sub.m(R.sup.2).sub.n(R.sup.3).sub.3(m+n)(1) wherein each R.sup.1 is independently selected from the group consisting of hydrogen, halogen, amino, oximino, a substituted or unsubstituted alkyl, alkenyl, alkenyloxy, alkynyl, alkylnyloxy, cycloaliphatic, cycloaliphatic-O, aryl, aryloxy, heteroaryl, heteroaryloxy, heteroalicyclic, heteroalicyclicoxy, acyl, and acyloxy group or a combination thereof; each R.sup.2 is independently a group of the general formula (2):
OYCOOR.sup.4(2) wherein Y is a substituted or unsubstituted (hetero)aromatic group having 4 to 14 ring atoms, a substituted or unsubstituted saturated or partially unsaturated 4- to 14-membered (hetero)cyclic group or (C(R.sup.5).sub.2).sub.o; R.sup.4 is a substituted or unsubstituted alkyl, alkenyl, alkynyl, cycloaliphatic, aryl, heteroaryl, or heteroalicyclic group, or a combination thereof; each R.sup.5 is independently selected from the group consisting of hydrogen, a substituted or unsubstituted alkyl, alkenyl, alkynyl, cycloaliphatic and aryl group; and o is an integer from 1 to 10; each R.sup.3 independently is a group of the general formula (3):
OYCONR.sup.6R.sup.7(3) wherein Y is as defined above; R.sup.6 is selected from the group consisting of hydrogen, a substituted or unsubstituted alkyl, alkenyl, alkynyl cycloaliphatic, aryl, heteroaryl, and heteroalicyclic group or a combination thereof or R.sup.1; R.sup.7 is a group of the general formula (4):
R.sup.8SiR.sup.9.sub.p(OR.sup.10).sub.3p(4) wherein R.sup.8 is an alkylene group, optionally interrupted by a heteroatom; each R.sup.9 is independently selected from the group consisting of hydrogen, halogen, amino, a substituted or unsubstituted alkyl, alkenyl, alkynyl, cycloaliphatic, aryl, heteroaryl, and heteroalicyclic group or a combination thereof; each R.sup.10 is independently selected from the group consisting of a substituted or unsubstituted alkyl, alkenyl, alkynyl, and acyl group; each p independently stands for 0, 1, or 2; m is independently 0, 1 or 2; and n is independently 1, 2, or 3, wherein the sum n+m is a maximum of 3; (B) at least one curing catalyst; and (C) at least one polymer having at least one silane-functional group of the general formula (II)
X.sub.oRSi(R.sup.a).sub.k(R.sup.b).sub.3k(II), wherein X is a divalent linking group containing at least one heteroatom; R is selected from divalent hydrocarbon residues having 1 to 12 carbon atoms; each R.sup.a is, independently of one another, selected from a hydrocarbon radical containing 1 to 20 carbon atoms and each R.sup.b is, independently of one another, selected from a hydroxyl group or a hydrolysable group, wherein R.sup.a and R.sup.b are substituents directly bound with the Si atom or the two of the substituents R.sup.a and R.sup.b form a ring together with the Si atom to which they are bound; k is 0, 1, or 2; and o is 0 or 1.

2. The curable composition according to claim 1, wherein the polyorganosiloxane is linked to the terminal group of the formula (I) via a linking group -A-, wherein -A- is a bond, O or a linear, branched or cyclic divalent group selected from hydrocarbon residues having 1 to 12 carbon atoms, alkylene, arylene, oxyalkylene, oxyarylene, siloxane-alkylene, siloxane-arylene, ester, amine, glycol, imide, amide, alcohol, carbonate, urethane, urea, sulfide, ether or a derivative or combination thereof.

3. The curable composition according to claim 1, wherein the polyorganosiloxane is a polydiorganosiloxane.

4. The curable composition according to claim 1, wherein each R.sup.1 independently of one another stands for an alkyl group having 1 to 10 carbon atoms; and/or each R.sup.2 independently of one another stands for a group of the general formula (2), wherein R.sup.4 stands for a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms; and/or the sum n+m is 2 or 3.

5. The curable composition according to claim 1, wherein the polyorganosiloxane (A) is obtainable by reacting a polyorganosiloxane having at least one terminal reactive group A (la) which may be reacted with a silane crosslinker having the formula (Ib)
CSi(R.sup.1).sub.m(R.sup.2).sub.n(R.sup.3).sub.3(m+n)(Ib), wherein C is a reactive group that reacts with the terminal reactive group A; and, R.sup.1, R.sup.2, R.sup.3, m, and n are the same as defined for the general formula (I).

6. The curable composition according to claim 1, wherein the group Si(R.sup.1).sub.m(R.sup.2).sub.n(R.sup.3).sub.3(m+n) in the general formula (I) is selected from methyl bis(ethyl lactato)silane, ethyl bis(ethyl lactato)silane, phenyl bis(ethyl lactato)silane, vinyl bis(ethyl lactato)silane, tri(ethyl lactato)silane, methyl bis(ethyl salicylato)silane, ethyl bis(ethyl salicylato)silane, phenyl bis(ethyl salicylato)silane, vinyl bis(ethyl salicylato)silane, tri(ethyl salicylato)silane, methyl bis(diethyl malato)silane, ethyl bis(diethyl malato)silane, phenyl bis(diethyl malato)silane, vinyl bis(diethyl malato)silane, tri(diethyl malato)silane and mixtures thereof.

7. The curable composition according to claim 1, wherein the curing catalyst (B) is selected from tin catalysts, titanium catalysts, aluminum catalyst, zirconium catalysts, or mixtures thereof.

8. The curable composition according to claim 1, wherein the polymer (C) has at least two silane-functional groups of the general formula (II).

9. The curable composition according to claim 1, wherein the polymer backbone of the polymer (C) is selected from polyethers, poly(meth)acrylic acid ester, polyesters, polyurethanes, or poly--olefins.

10. The curable composition according to claim 1, wherein the divalent linking group X in the general formula (II) is selected from O, S, N(R), RO, a substituted or unsubstituted amide, carbamate, urethane, urea, imino, carboxylate, carbamoyl, amidino, carbonate, sulfonate or sulfinate group; and/or R in the general formula (II) is selected from a methylene, ethylene, or n-propylene; and/or each R.sup.a in the general formula (II) is, independently of one another, selected from C.sub.1 to C.sub.8 alkyl groups; and/or each R.sup.b in the general formula (II) is, independently of one another, selected from a hydroxyl, C.sub.1 to C.sub.8 alkoxy groups, C.sub.1 to C.sub.8 acyloxy groups, or OYCOOR.sup.4, wherein Y and R.sup.4 are as defined for the general formula (2) above; and/or k is 0 or 1.

11. The curable composition according to claim 1, wherein the composition comprises about 0.1 to 10% by weight, of the polymer (C) based on the total weight of the composition.

12. The curable composition according to claim 1, wherein the curable composition further comprises (D) at least one adhesion promoter that comprises at least one compound selected from: (i) aminosilanes, optionally oligomerized together with alkyl-, alkenyl- or aryl-alkoxysilanes; (ii) oligomers obtained from the condensation of aminosilanes, optionally oligomerized together with alkyl-, alkenyl- or aryl-alkoxysilanes; or (iii) mixtures thereof.

13. The curable composition according to claim 12, wherein (i) the amount of the polyorganosiloxane (A) is from about 20 to about 97% by weight, based on the total weight of the composition; and/or (ii) the amount of the curing catalyst (B) is from about 0.05 to about 2% by weight, based on the total weight of the composition; and/or (iii) the amount of the polymer (C) is from about 0.1 to about 10% by weight, based on the total weight of the composition; and/or (iv) the amount of the adhesion promoter (D) is 0.01 to 5% by weight, based on the total weight of the composition.

14. An adhesive, sealant, or coating material comprising the curable composition according to claim 1.

15. (canceled)

16. A method of sealing, coating or bonding a substrate comprising applying the curable composition according to claim 1 to at least one surface of the substrate.

17. The curable composition according to claim 1, wherein (i) the amount of the polyorganosiloxane (A) is from about 25 to 70% by weight, based on the total weight of the composition; and/or (ii) the amount of the curing catalyst (B) is from about 0.1 to 1.5% by weight, based on the total weight of the composition; and/or (iii) the amount of the polymer (C) is from about 0.1 to 5% by weight, based on the total weight of the composition; and/or (iv) the amount of the adhesion promoter (D) is 0 to about 5% by weight, based on the total weight of the composition.

Description

EXAMPLES

[0292] The formulations were prepared as described in the Tables below and subjected to curing performance tests as follows:

[0293] Determination of Skin-over time (SOT): Skin-over time (SOT) is defined as the time required for the material to form a non-tacky surface film. The determination of the skin overtime is carried out according to DIN 50014 under standard climate conditions (23+/2 C., relative humidity 50+/5%). The temperature of the sealant must be 23+/2 C., with the sealant stored for at least 24 h beforehand in the laboratory. The sealant is applied to a sheet of paper and spread out with a putty knife to form a skin (thickness about 2 mm, width about 7 cm). The stopwatch is started immediately. At intervals, the surface is touched lightly with the fingertip and the finger is pulled away, with sufficient pressure on the surface that an impression remains on the surface when the skin formation time is reached. The skin-over time is reached when sealing compound no longer adheres to the fingertip. The skin-over time (SOT) is expressed in minutes.

[0294] Measurement of Shore A hardness: Shore A hardness was measured according to ISO 868.

[0295] Determination of the depth of cure (DOC): A strip of the material with a height of 10 mm (+/1 mm) and width of 20 mm (+/2 mm) was applied over a plastic foil (PP) using a Teflon spatula. After storing the sample for 24 hours at normal conditions (23+/2 C., relative humidity 50+/5%), a section of the strip was cut off and the thickness of the cured layer was measured with a caliper. The depth of cure after 24 hours is expressed in millimeters.

[0296] Assessment of the mechanical properties (tensile test): The Tensile test determines the breaking force, elongation at break and yield stress value (e-module), according to DIN 53504. The tests took place using S3 specimen at normal conditions (23+/2 C., relative humidity 50+/5%). The measurement was carried out after 7 days of curing. Procedure: the prepolymer mixture (formulation) was spread on an even surface forming a film with a thickness of 2 mm. The film was allowed to cure under normal conditions (see above) for seven days, and then the dumbbell specimen was punched out. Three specimens were used for each determination. The test was carried out under normal conditions. The test specimens have to be at the same temperature at which the measurement will take place. Before the measurement, the thickness of the test specimens is determined at least at three different positions, at the middle and at the extremes, with a caliper. The mean value is introduced in the measuring software. The test specimens are clamped into the tensile tester so that the longitudinal axis coincides with the mechanical axis of the tensile tester and comprises the largest possible surface of the rod heads, without clamping the middle bar. Then the dumbbell is stretched to <0.1 MPa with a rate of 50 mm/min. Then, the force-elongation curve is recorded with a line speed of 50 mm/min. Evaluation: The following values are determined: breaking force in [N/mm.sup.2] elongation at break in [%] and modulus at 100% elongation in [N/mm.sup.2].

[0297] Peel test: If possible and needed, substrate (test panel) is cleaned prior to application using a suitable solvent. A strip of the material with a height of 10 mm (+/1 mm) and width of 20 mm (+/2 mm) was applied over the substrate using a Teflon spatula cartridge and cartridge gun. The sample was stored for 7 days at normal conditions (23+/2 C., relative humidity 50+/5%). The cured material was cut back for at least 15 mm with a shape blade and the bead pulled by hand. Failure mode was recorded as following: [0298] : Cohesion failure (CT) [0299] : Adhesion failure (AF) with strong resistance [0300] x: Adhesion failure (AF).

Example 1

[0301] The compositions 1-A and 1-B according to the invention and comparative compositions 1-C to 1-F were prepared by using the raw materials listed in Table 1. In particular, ,-dihydroxy-terminated polydimethylsiloxane and vinyl tris(ethyl actato)silane were first reacted to create a lactate silane-terminated polydimethylsiloxane in presence of plasticizer, extender and (endcapping) catalyst. In subsequent steps other components were added. Mixing occurred in a dual asymmetric centrifugal mixer (SpeedMixer DAC 400.2 VAC-P) at 0-2500 RPM for 100-120 s and under vacuum (80-200 mbar) per step.

TABLE-US-00001 TABLE 1 Components (parts by weight) 1-A 1-B 1-C 1-D 1-E 1-F ,-dihydroxy-terminated 51.77 51.77 51.77 51.77 51.77 51.77 polydimethylsiloxane with a viscosity of 80,000 cST Plasticizer (Polydimethylsiloxane 22.66 22.66 22.66 22.66 22.66 22.66 with a viscosity of 1,000 cST) Plasticizer (Polydimethylsiloxane 4.44 4.44 4.44 4.44 4.44 4.44 with a viscosity of 100,000 cST) Dearomatized aliphatic fluids - 4.44 4.44 4.44 4.44 4.44 4.44 Extender Vinyl tris(ethyl lactato)silane 5.0 5.0 5.0 5.0 5.0 5.0 Highly dispersed silica 8.88 8.88 8.88 8.88 8.88 8.88 3-Aminopropyltrimethoxysilane 0.9 0.9 0.9 0.9 0.9 0.9 3-(N,N-dimethylamino)propyltrimethoxysilane 0.75 0.75 0.75 0.75 0.75 0.75 DOTL (dioctyltin dilaurate) 0.17 0.17 0.17 0.17 0.17 0.17 Silane-modified polymer (Desmoseal 1.0 S XP 2749, Covestro) Silane-modified polymer (Geniosil 1.0 STP-E10, Wacker) PPG 2000 (Voranol 2000) 1.0 PPG 12000 (Acclaim 12200) 1.0 PPG 18000 (Acclaim 18200) 1.0

TABLE-US-00002 TABLE 2 Peel test of the compositions directly after mixing 1-A 1-B 1-C 1-D 1-E 1-F PMMA transparent x x x x Perspex Asterite 1A17 x x x x PVC

Example 2

[0302] The compositions 2-A to 2-F according to the invention were prepared by using the raw materials listed in Table 3 according to the similar method described in Example 1.

TABLE-US-00003 TABLE 3 Components (wt %) 2-A 2-B 2-C 2-D 2-E 2-F ,-dihydroxy-terminated polydimethylsiloxane 52.24 52.03 51.77 51.25 49.68 47.06 with a viscosity of 80,000 cST Plasticizer (Polydimethylsiloxane with a 22.86 22.77 22.66 22.43 21.74 20.6 viscosity of 1,000 cST) Plasticizer (Polydimethylsiloxane with a 4.48 4.46 4.44 4.39 4.26 4.03 viscosity of 100,000 cST) Dearomatized aliphatic fluids - extender 4.48 4.46 4.44 4.39 4.26 4.03 Vinyl tris(ethyl lactato)silane 5.05 5.02 5.0 4.95 4.8 4.55 Highly dispersed silica 8.96 8.92 8.88 8.79 8.52 8.07 3-Aminopropyltrimethoxysilane 0.9 0.9 0.9 0.9 0.86 0.81 3-(N,N-dimethylamino)propyltrimethoxysilane 0.76 0.75 0.75 0.74 0.72 0.68 DOTL (dioctyltin dilaurate) 0.17 0.17 0.17 0.17 0.16 0.15 Silane-modified polymer (Desmoseal 0.1 0.5 1.0 2.0 5.0 10.0 S XP 2749, Covestro)

TABLE-US-00004 TABLE 4 Peel test of the compositions directly after mixing 2-A 2-B 2-C 2-D 2-E 2-F PMMA transparent Perspex Asterite 1A17 Polycarbonate Polystyrene PVC

Example 3

[0303] The compositions 3-A and 3-B according to the invention and comparative composition 3-C were prepared by using the raw materials listed in Table 5. In particular, ,-dihydroxy-terminated polydimethylsiloxane and vinyl tris(ethyl lactato)silane were first reacted to create a lactate silane-terminated polydimethylsiloxane in presence of plasticizer, extender and (endcapping) catalyst. In subsequent steps other components were added. Mixing occurred in a PC Lab Mixer (PC Laborsystem GmbH) equipped with blade stirrer and dissolver blade at 0-200 RPM under N2 atmosphere or vacuum (80-200 mbar) for 3-10 minutes per step.

TABLE-US-00005 TABLE 5 Components (wt %) 3-A 3-B 3-C , -dihydroxy-terminated polydimethylsiloxane 51.77 51.77 51.77 with a viscosity of 80,000 cST Plasticizer (Polydimethylsiloxane with a 22.83 21.98 23.66 viscosity of 1,000 cST) Plasticizer (Polydimethylsiloxane with a 4.28 4.12 4.44 viscosity of 100,000 cST) Dearomatized aliphatic fluids - extender 4.44 4.44 4.44 Vinyl tris(ethyl lactato)silane 5.0 5.0 5.0 Highly dispersed silica 8.88 8.88 8.88 3-Aminopropyltrimethoxysilane 0.9 0.9 0.9 3-(N,N-dimethylamino)propyltrimethoxysilane 0.74 0.74 0.75 DOTL (dioctyltin dilaurate) 0.17 0.17 0.17 Silane-modified polymer (Desmoseal S XP 1.0 2.0 0 2749, Covestro)

TABLE-US-00006 TABLE 6 Mechanical properties and peel test directly after mixing 3-A 3-B 3-C SOT (min) 15 7 18 Shore A 1 d n/a 18 19 Shore A 7 d 22 21 20 cure through (mm in 24 h) n/a 2.7 2.84 Modulus at 100% 0.50 n/a 0.49 Elongation at break 620.1 n/a 491.4 Peel test PMMA transparent x Perspex Asterite 1A17 x PVC Brass x

TABLE-US-00007 TABLE 7 Mechanical properties and peel test after storage (4 weeks; room temperature) 3-A 3-B 3-C SOT (min) 20 21 20 Shore A 1 d 19 11 n/a Shore A 7 d 20 21 n/a cure through (mm in 24 h) 3.46 3.12 2.68 Modulus at 100% 0.46 n/a n/a Elongation at break 470.8 n/a n/a Peel test PMMA transparent x Perspex Asterite 1A17 x PVC Brass ~ x

TABLE-US-00008 TABLE 8 Mechanical properties and peel test after storage (8 weeks; room temperature) 3-A 3-B SOT (min) 23 27 Shore A 1 d 13 13 Shore A 7 d 18 18 cure through (mm in 24 h) 3.2 3.08 Modulus at 100% 0.43 0.38 Elongation at break 402.3 505.3 Peel test PMMA transparent Perspex Asterite 1A17 PVC Brass ~ ~