High modulus curable composition

Abstract

The invention relates to a curable composition comprising a) at least one polymer having at least one terminal group of the general formula (I)
-A.sub.n-RSiXYZ(I),
wherein A is a divalent bonding group containing at least one heteroatom, R is selected from divalent hydrocarbon residues having 1 to 12 carbon atoms, X, Y, Z are, independently of one another, selected from the group consisting of a hydroxyl group and C.sub.1 to C.sub.8 alkyl, C.sub.1 to C.sub.8 alkoxy, and C.sub.1 to C.sub.8 acyloxy groups, wherein X, Y, Z are substituents directly bound with the Si atom or the two of the substituents X, Y, Z form a ring together with the Si atom to which they are bound, and at least one of the substituents X, Y, Z is selected from the group consisting of a hydroxyl group, C.sub.1 to C.sub.8 alkoxy or C.sub.1 to C.sub.8 acyloxy groups, and n is 0 or 1; and b) at least one compound of the general formula (II) ##STR00001##
wherein R is same or different and is, independently from one another, selected from the group consisting of a hydrogen atom and hydrocarbon residues having 1 to 12 carbon atoms, and Ar is selected from aryl groups, and adhesive, sealant, or coating materials comprising the composition and use thereof.

Claims

1. A curable composition comprising a) at least one polymer having at least one terminal group of the general formula (I)
-A.sub.n-RSiXYZ(I), wherein A is a divalent bonding group containing at least one heteroatom, R is selected from divalent hydrocarbon residues having 1 to 12 carbon atoms, X, Y, Z are, each independently of one another, selected from the group consisting of a hydroxyl group and C.sub.1 to C.sub.8 alkyl, C.sub.1 to C.sub.8 alkoxy, and C.sub.1 to C.sub.8 acyloxy groups, wherein X, Y, Z are substituents directly bound with the Si atom or the two of the substituents X, Y, Z form a ring together with the Si atom to which they are bound, and at least one of the substituents X, Y, Z is selected from the group consisting of a hydroxyl group, C.sub.1 to C.sub.8 alkoxy and C.sub.1 to C.sub.8 acyloxy groups, and n is 0 or 1; and b) at least one compound of the general formula (II) ##STR00005## wherein each R is the same or different and is, independently from one another, selected from the group consisting of a hydrogen atom and hydrocarbon residues having 1 to 12 carbon atoms, and each Ar is independently selected from aryl groups.

2. The curable composition according to claim 1, wherein the at least one polymer has at least two terminal groups of the general formula (I).

3. The curable composition according to claim 1, wherein each Ar in the general formula (II) is a phenyl group.

4. The curable composition according to claim 1, wherein R in the general formula (II) is selected from a methyl or ethyl group.

5. The curable composition according to claim 1, wherein the composition comprises the at least one compound of the general formula (II) in an amount of 1 to 60 wt. % based on the total weight of the composition.

6. The curable composition according to claim 1, wherein the each divalent bonding group A in the general formula (I) is independently selected from an oxygen atom, a substituted or unsubstituted amide, a carbamate, a urethane, an urea, an amino, a carboxylate, a carbamoyl, an amidino, a carbonate, a sulfonate, a sulfinate or an N(R) group, wherein R is selected from the group consisting of a hydrogen atom, an alkyl residue having 1 to 12 carbon atoms or an aryl residue having 1 to 12 carbon atoms.

7. The curable composition according to claim 1, wherein the substituents X, Y, Z in the general formula (I) are, each independently of one another, selected from a hydroxyl, a methyl, an ethyl, a methoxy, or an ethoxy group, wherein at least one of the substituents is a hydroxyl group, or a methoxy or an ethoxy group.

8. The curable composition according to claim 1, wherein R in the general formula (I) is selected from a methylene, ethylene, or n-propylene.

9. The curable composition according to claim 1, wherein the composition is a one component composition.

10. The curable composition according to claim 1, wherein the composition further comprises at least one filler.

11. The curable composition according to claim 1, wherein the composition further comprises at least one adhesion promoter and/or at least one catalyst.

12. Cured reaction products of the curable composition according to claim 1.

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

Description

EXAMPLES

(1) Synthesis of Diphenyltetramethoxydisiloxane

(2) Phenyltrimethoxysilane (195.2 g) was placed in a 3 neck round bottom flask (0.5 L) equipped with a magnetic stirring bar a thermometer and a dropping funnel. 1 N Hydrochloric acid (8.8 g with a molar ratio of water:methoxy 6:1) was added dropwise to the silane over a period of 7 h, whereby the temperature of the mixture was not allowed to exceed 40 C. The mixture was left stirring at 600 RPM for 10 h after which the reaction was stopped and the mixture stored at 25 C. for at least one day prior distillation. Conversion of the reaction after removal of the starting materials was 76%. Purification of the reaction mixture occurred via vacuum distillation. At a vacuum of 1 mbar two fractions were isolated. The first fraction came at 130 C. and contained unreacted phenyltrimethoxysilane. The second fraction was isolated at 230 C. and contained the desired product 1,2-diphenyltetramethoxydisiloxane (36% yield).

(3) General Procedure for Manufacturing the Polymers

(4) Polymer 1 (gamma-silane-terminated polymer): 282 g (15 mmol) of polypropylene glycol 18000 (hydroxyl value=6.0) was dried in a 500 ml three-neck flask at 80-90 C. under vacuum. Under a nitrogen atmosphere at 80 C., 0.1 g of dibutyltin laurate was added, and 7.2 g (32 mmol) 3-isocyanatopropyltrimethoxysilane (% NCO=18.4) was then added to it. After stirring for one hour at 80 C., the resulting polymer was cooled. After adding 3 g light stabilizer (Tinuvin 770 DF) and 6 g Geniosil XL 10 to the reactor while stirring and homogenizing for 10-30 minutes at 80 C., the resulting polymer was stored in a moisture-proof glass vessel under a nitrogen atmosphere before being processed further into a curable composition.

(5) Polymer 2 (gamma-silane-terminated polymer): 384.02 g (33.88 mmol) of polypropylene ether polyol (Acclaim 12200, hydroxyl value=9.90) was dried in a 500 ml three-necked flask at 80-90 C. under vacuum. Under a nitrogen atmosphere, 0.1 g of dioctyltin dilaurate (TIB Kat 216) was added with stirring. Then, 15.19 g (68.33 mmol) of IPDI was added (NCO/OH ratio=2.02) with stirring. The mixture was left for one hour at 80-90 C. The conversion was accomplished with NCO monitoring, and as soon as the theoretical NCO value of the prepolymer had been reached titrimetrically (% NCO<0.75), 17.09 g (72.60 mmol) of N-(3-(Trimethoxysilyl)propyl)butylamine (Dynasylan 1189) was added with stirring and the mixture was left for half an hour at 80-90 C. (% NCO=0.00). A linear polymer was obtained. After adding 6.47 g light stabilizer (Tinuvin 770 DF) and 8.63 g Geniosil XL 10 to the reactor while stirring and homogenizing for 10-30 minutes at 80 C., the resulting polymer was stored in a moisture-proof glass vessel under a nitrogen atmosphere before being processed further into a curable composition.

(6) Test Method for Determining Tensile Strength and Elongation at Break

(7) Tensile strength and elongation at break were determined according to DIN 53504. Dumbbell specimens with the following dimensions were used: thickness 2+/0.2 mm; bar width 10+/0.5 mm; bar length approx. 45 mm; and total length 9 cm.

(8) 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 (23+/2 C., relative humidity 50+/5%) for 7 days, and then the dumbbell specimen was punched out. Three specimens were used for each determination. The test was carried out under normal conditions (23+/2 C., relative humidity 50+/5%) and the measurement was carried out after 7 days of curing. 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.

(9) Evaluation: The following values are determinedbreaking force in [N/mm.sup.2] and elongation at break in [%].

Example 1

(10) A polyether-based alpha-silane-terminated polymer (Geniosil STP-E30, Wacker), diphenyltetramethoxydisiloxane and N-(2-Aminoethyl)-3-aminopropyltrimethoxysilane (Geniosil GF 91, Wacker) were mixed together in the speedmixer for 30 s at a speed of 2750 U/min. The catalyst TIP Kat 216 was then added and the mixture was stirred again in the speedmixer for additional 30 s at a speed of 2750 U/min. The formulations described in Table 1 below were then left to cure at normal conditions for 7 days and tested for mechanical properties.

(11) TABLE-US-00002 TABLE 1 Formulations of 1A to 1D and test results 1A 1B 1C 1D Geniosil STP-E30 (wt. %) 98.6 88.6 58.6 48.6 Geniosil GF 91 (wt. %) 1.0 1.0 1.0 1.0 TIP Kat 216 (wt. %) 0.4 0.4 0.4 0.4 diphenyltetramethoxydisiloxane 10.0 40.0 50.0 (wt. %) Tensile Strength at break [N/mm.sup.2] 0.73 0.64 3.72 5.16 Elongation (%) 106 136 375 401 Example 1A is a comparative example. Examples 1B to 1D are according to the invention.

Example 2

(12) Polymer 1 obtained according to the above procedure, diphenyltetramethoxydisiloxane or divinyltetramethoxydisiloxane, and N-(2-Aminoethyl)-3-aminopropyltrimethoxysilane (Geniosil GF 91, Wacker) were mixed together in the speedmixer for 30 s at a speed of 2750 U/min. The catalyst TIP Kat 216 was then added and the mixture was stirred again in the speedmixer for additional 30 s at a speed of 2750 U/min. The formulations described in Table 2 below were then left to cure at normal conditions for 7 days and tested for mechanical properties.

(13) TABLE-US-00003 TABLE 2 Formulations of 2A to 2G and test results 2A 2B 2C 2D 2E 2F 2G 2H Polymer 1 (wt. %) 98.6 88.6 78.6 68.6 58.6 48.6 38.6 58.6 Geniosil GF 91 (wt. %) 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 TIP Kat 216 (wt. %) 0.40 0.40 0.40 0.40 0.40 0.40 0.40 0.40 diphenyltetramethoxydisiloxane 10.0 20.0 30.0 40.0 50.0 60.0 (wt. %) divinyltetramethoxydisiloxane 40.0 (wt. %) Tensile Strength at break 0.71 0.78 0.94 3.07 6.81 8.06 6.41 0.09 [N/mm.sup.2] Elongation (%) 71 77 85 265 383 588 339 4 Examples 2A are 2H are comparative example. Examples 2B to 2G are according to the invention.

Example 3

(14) Polymer 2 obtained according to the above procedure, diphenyltetramethoxydisiloxane and N-(2-Aminoethyl)-3-aminopropyltrimethoxysilane (Geniosil GF 91, Wacker) were mixed together in the speedmixer for 30 s at a speed of 2750 U/min. The catalyst TIP Kat 216 was then added and the mixture is stirred again in the speedmixer for additional 30 s at a speed of 2750 U/min. The formulations described in Table 3 below were then left to cure at normal conditions for 7 days and tested for mechanical properties.

(15) TABLE-US-00004 TABLE 3 Formulations of 3A and 3B and test results 3A 3B Polymer 2(wt. %) 98.60 58.60 Geniosil GF 91 (wt. %) 1.00 1.00 TIP Kat 216 (wt. %) 0.40 0.40 diphenyltetramethoxydisiloxane (wt. %) 40.00 Tensile Strength at break [N/mm.sup.2] 0.86 7.75 Elongation (%) 65 411 Example 3A is a comparative example. Example 3B is according to the invention.

Examples 4 and 5

(16) Polymer 1 obtained according to the above procedure, silica gel HDK 20 (Wacker), diphenyltetramethoxydisiloxane, 3-aminopropyltrimethoxysilane (Geniosil GF 96, Wacker) and 3-methacryloxypropyltrimethoxysilane (Geniosil GF 31, Wacker) were mixed together in the speedmixer for 60 s at a speed of 3500 U/min. The catalyst TIP Kat 216 was then added and the mixture was stirred again in the speedmixer for additional 60 s at a speed of 3500 U/min. The formulations described in Tables 4 and 5 below were then left to cure at normal conditions for 7 days and tested for mechanical properties.

(17) TABLE-US-00005 TABLE 4 Formulations of 4A to 4G and test results 4A 4B 4C 4D 4E 4F 4G Polymer 1 (wt. %) 94.0 84.0 80.0 76.0 64.0 54.0 44.0 HDK H20 (wt. %) 10.0 10.0 10.0 10.0 10.0 10.0 Geniosil GF 96 1.60 1.60 1.60 1.60 1.60 1.60 1.60 (wt. %) Geniosil GF 31 4.00 4.00 4.00 4.00 4.00 4.00 4.00 (wt. %) TIP Kat 216 0.40 0.40 0.40 0.40 0.40 0.40 0.40 (wt. %) diphenyltetramethoxy- 4.00 8.00 20.0 30.0 40.0 disiloxane (wt. %) Tensile Strength 0.93 2.71 3.72 4.24 6.87 10.39 15.02 at break [N/mm.sup.2] Elongation (%) 52 145 206 204 266 425 685

(18) TABLE-US-00006 TABLE 5 Formulations of 5A to 5F and test results 5A 5B 5C 5D 5E 5F Polymer 1 (wt. %) 59.00 49.00 39.00 69.00 59.00 49.00 HDK H20 (wt. %) 15.00 15.00 15.00 5.00 5.00 5.00 Geniosil GF 96 (wt. %) 1.60 1.60 1.60 1.60 1.60 1.60 Geniosil GF 31 (wt. %) 4.00 4.00 4.00 4.00 4.00 4.00 TIP Kat 216 (wt. %) 0.40 0.40 0.40 0.40 0.40 0.40 diphenyltetramethoxydisiloxane 20.00 30.00 40.00 20.00 30.00 40.00 (wt. %) Tensile Strength at break 11.48 17.52 13.28 3.16 5.53 8.37 [N/mm.sup.2] Elongation (%) 387 602 434 189 305 339 Examples 4A and 4B are comparative examples. Examples 4C to 4G and 5A to 5F are according to the invention.

Example 6

(19) Polymer 1 obtained according to the above procedure, silica gel Aerosil OX 50, various amounts of diphenyltetramethoxydisiloxane or phenyltrimethoxysilane and N-(2-Aminoethyl)-3-aminopropyltrimethoxysilane (Geniosil GF 91, Wacker) or a combination of 3-aminopropyltrimethoxysilane (Geniosil GF 96, Wacker) and 3-methacryloxypropyltrimethoxysilane (Geniosil GF 31, Wacker) were mixed together in the speedmixer for 60 s at a speed of 3500 U/min. The catalyst TIP Kat 216 was then added and the mixture was stirred again in the speedmixer for additional 60 s at a speed of 3500 U/min. The formulations described in Table 6 below were then left to cure at normal conditions for 7 days and tested for mechanical properties.

(20) TABLE-US-00007 TABLE 6 Formulations of 6A to 6G and test results 6A 6B 6C 6D 6E 6F 6G Polymer 1 (wt. %) 84.00 84.00 82.00 80.00 76.00 76.00 44.00 Aerosil OX 50 (wt. %) 10.00 10.00 10.00 10.00 10.00 10.00 10.00 Geniosil GF 91 (wt. %) 5.60 5.60 5.60 5.60 Geniosil GF 96 (wt. %) 1.60 1.60 1.60 Geniosil GF 31 (wt. %) 4.00 4.00 4.00 TIP Kat 216 (wt. %) 0.40 0.40 0.40 0.40 0.40 0.40 0.40 diphenyltetramethoxydisiloxane 2.00 4.00 8.00 8.00 40.00 (wt. %) Tensile Strength at break 1.57 1.51 2.06 1.98 2.07 1.91 7.29 [N/mm.sup.2] Elongation (%) 102 114 152 151 158 128 279 Examples 6A and 6B are comparative examples. Examples 6C to 6G are according to the invention.