CROSSLINKABLE ORGANOPOLYSILOXANE COMPOSITIONS

Abstract

Moisture curable RTV-1 compositions with rapid curing and a modulus which is adjustable over a wide range include organopolysiloxanes having on-chain and side-chain silicon-bonded α-aminoalkyl groups and at least on average two silicon-bonded alkoxy groups, trialkoxyorganylsilanes and/or tetraalkoxysilanes, and organopolysiloxanes bearing alkoxysilyl groups.

Claims

1.-9. (canceled)

10. A crosslinkable organopolysiloxane composition produced from (A) organosilicon compounds comprising units of the formula
[R.sup.1.sub.2NCR.sup.4.sub.2].sub.bSiR.sup.3.sub.c(OR.sup.2).sub.aO.sub.(4-a-b-c)/2  (I), where R.sup.1 each is identical or different and is a monovalent, optionally substituted hydrocarbyl radical, R.sup.2 each is identical or different and is a monovalent, optionally substituted hydrocarbyl radical, R.sup.3 each is identical or different and is a monovalent hydrocarbyl radical, R.sup.4 each is identical or different and is hydrogen or a monovalent, optionally substituted hydrocarbyl radical, a is 0, 1, 2 or 3, b is 0, 1 or 2, and c is 0, 1, 2 or 3, with the proviso that organosilicon compound (A) has at least one unit of the formula (I) where a=b=c=1, the sum of a+b+c=2 in at least 50% of the units of the formula (I), and the organosilicon compound contains at least 2 groups —OR.sup.2; optionally, (B) one or more silanes of the formula
R.sup.1.sub.2NCR.sup.4.sub.2SiR.sup.3(OR.sup.2).sub.2  (XI), where R.sup.1, R.sup.2, R.sup.3, and R.sup.4 are each identical or different and have one of the definitions indicated above, (C) one or more silanes of the formula
R.sup.6.sub.dSi(OR.sup.7).sub.4-d  (II) and/or partial hydrolysates thereof having up to 10 silicon atoms, where R.sup.6 has a definition indicated for R.sup.3, R.sup.7 each is identical or different and is a monovalent, optionally substituted hydrocarbyl radical or a radical —N═CR.sup.5.sub.2, R.sup.5 each is identical or different and has a definition indicated for R.sup.2, and d is 0 or 1; and (D) organosilicon compounds selected from the group consisting of (D1) compounds comprising units of the formulae
R.sup.8.sub.mSi(OR.sup.9).sub.3-mO.sub.1/2  (III),
R.sup.8.sub.mSi(OR.sup.9).sub.2-mO.sub.2/2  (IV), and
R.sup.8.sub.mSi(OR.sup.9).sub.1-mO.sub.3/2  (V), where R.sup.8 each is identical or different and is a monovalent hydrocarbyl radical, R.sup.9 each is identical or different and is a monovalent hydrocarbyl radical, and M in each case is 0 or 1, with the proviso that compound (D1) has at least 3 groups —OR.sup.9 per molecule and has a weight-average molecular weight Mw of 1000 to 3000 g/mol, (D2) compounds of the formula)
(R.sup.10O).sub.3Si—R.sup.11—Si(OR.sup.10.sub.3  (VII), where R.sup.10 each is identical or different and is a monovalent, optionally substituted hydrocarbyl radical optionally interrupted by one or more heteroatoms, R.sup.11 each is identical or different and is a divalent, optionally substituted hydrocarbyl radical optionally interrupted by one or more heteroatoms, and (D3) compounds comprising units of the formulae
R.sup.8.sub.3SiO.sub.1/2  (XII),
SiO.sub.4/2  (VI), and
R.sup.8.sub.mSi(OR.sup.9).sub.1-mO.sub.3/2  (V) and also, optionally, further comprising units of the formulae (III) and (IV), where R.sup.8, R.sup.9 and m have a definition indicated for them above, with the proviso that m is 0 and compound (D3) has at least 3 groups —OR.sup.9 per molecule and has a weight-average molar weight Mw of 1000 to 4000 g/mol.

11. The organopolysiloxane composition of claim 10, wherein organosilicon compounds (A) are prepared by reaction of organosilicon compounds having at least two OH groups (A0) with silanes (B) and silanes (C′) of the formula R.sup.3Si(OR.sup.2).sub.3 and/or Si(OR.sup.2).sub.4, optionally in the presence of catalyst (K) and, optionally, in the presence of further substances, and R.sup.2 and R.sup.3 have one of the definitions indicated for them above.

12. The organopolysiloxane composition of claim 11, wherein chain extender (B) is present in an amount such that the molar ratio of component (B) to Si—OH in component (A0) is less than 1.

13. The organopolysiloxane composition of claim 10, wherein radical R.sup.7 comprises alkyl radicals having 1 to 6 carbon atoms.

14. The organopolysiloxane composition of claim 11, wherein radical R.sup.7 comprises alkyl radicals having 1 to 6 carbon atoms.

15. The organopolysiloxane composition of claim 12, wherein radical IC comprises alkyl radicals having 1 to 6 carbon atoms.

16. The organopolysiloxane composition of claim 10, wherein component (D) comprises exclusively compounds (D1), or exclusively compounds (D2), or a mixture of compounds (D1) and (D2).

17. The organopolysiloxane composition of claim 11, wherein component (D) comprises exclusively compounds (D1), or exclusively compounds (D2), or a mixture of compounds (D1) and (D2).

18. The organopolysiloxane composition of claim 12, wherein component (D) comprises exclusively compounds (D1), or exclusively compounds (D2), or a mixture of compounds (D1) and (D2).

19. The organopolysiloxane composition of claim 10, when the composition comprises isocyanates in amounts of not more than 25 mol %, based on the molar amount of the units [R.sup.1.sub.2NCR.sup.4.sub.2]Si≡.

20. A process for producing an organopolysiloxane composition of claim 10, comprising mixing the individual components in any desired order.

21. The process of claim 20, wherein, in a first step organosilicon compounds having at least two OH groups (A0) are mixed with silanes (B), silanes (C′), and optionally catalyst (K), and also, optionally, plasticizer (G), and left to react, and then in a second step the reaction material obtained in the first step is mixed with silanes (C), organosilicon compounds (D), and also, optionally, further components selected from components (E) catalysts, (F) fillers, (G) plasticizers, (H) adhesion promoters (J) stabilizers, and (L) additives.

22. A shaped body produced by crosslinking an organopolysiloxane composition of claim 10.

23. A shaped body produced by crosslinking an organopolysiloxane composition prepared by the process of claim 20.

Description

INVENTIVE EXAMPLE 1

[0184] After the polymers prepared above have been aged for a time of 24 hours, 230 g of polymer P1 are mixed with 84 g of a trimethylsilyl-terminal dimethylpolysiloxane having a viscosity of 1000 mPa.Math.s, and 3 g of N-aminoethyl-aminopropyltrimethoxysilane and 4 g of vinyltrimethoxysilane are added. To this were added 3 g of component (D1), consisting of 16.0 mol % of units of the formula MeSi(OEt).sub.2O.sub.1/2, 46.4 mol % of units of the formula MeSi(OEt)O.sub.2/2 and 36.5 mol % of units of the formula MeSiO.sub.3/2 and also 0.2 mol % of the formula (Me).sub.2Si(OEt)O.sub.1/2 and 0.9 mol % of the formula Me.sub.2SiO.sub.2/2. Then 32 g of a fumed silica having a BET surface area of 150 m.sup.2/g are mixed in homogeneously, and 1 g of a tin catalyst, prepared by reaction of di-n-butyltin diacetate and tetraethoxysilane, and 0.5 g of octylphosphonic acid are added. The mixture is devolatilized under a pressure of 100 mbar for 5 minutes.

[0185] The rheology of the resulting material is characterized according to DIN 54458. Furthermore, the elastomer properties are determined on 2 mm vulcanizate sheets according to DIN 53504. The sheets are produced by vulcanization of a 2 mm layer, applied to PE film, at 23° C./50% relative atmospheric humidity.

[0186] The storage stability was determined by accelerated aging of the paste in cartridges at 70° C.

[0187] The properties are set out in Table 2.

INVENTIVE EXAMPLES 2 TO 6

[0188] The procedure described in inventive example 1 is repeated in each case, with the modification that polymers P2 to P6 were used instead of polymer P1. The results are found in Table 2.

INVENTIVE EXAMPLE 7

[0189] The procedure described in inventive example 1 is repeated, with the modification that rather than 3 g only 2 g of component (D1) were used, consisting of 16.0 mol % of units of the formula MeSi(OEt).sub.2O.sub.1/2, 46.4 mol % of units of the formula MeSi(OEt)O.sub.2/2 and 36.5 mol % of units of the formula MeSiO.sub.3/2 and also 0.2 mol % of the formula (Me).sub.2Si(OEt)O.sub.1/2 and 0.9 mol % of the formula Me.sub.2SiO.sub.2/2, and additionally 1 g of component (D2) (MeO).sub.3Si—CH.sub.2—CH.sub.2—Si(OMe).sub.3 was used.

INVENTIVE EXAMPLE 8

[0190] The procedure described in inventive example 1 is repeated, with the modification that a combination of 1 part of (D2) where R.sup.10=Me and R.sup.11=—CH.sub.2—CH.sub.2— and also 2 parts of (D3) with 54 mol % of MeSiO.sub.1/2 units, 42 mol % of SiO.sub.4/2 units and 4 mol % of Si(OEt)O.sub.3/2 units is used.

COMPARATIVE EXAMPLE C1

[0191] The procedure described in inventive example 1 is repeated, with the modification that polymer P8 is used.

COMPARATIVE EXAMPLE C2

[0192] The procedure described in inventive example 1 is repeated, with the modification that no component (D1) is used.

COMPARATIVE EXAMPLE C3

[0193] The procedure described in inventive example 6 is repeated, with the modification that no component (D1) is used.

COMPARATIVE EXAMPLE C4

[0194] The procedure described in comparative example C1 is repeated, with the modification that a polymer component P9 was prepared in the same way as for P8, with the difference that a mixture of 280 parts by weight of an α,ω-dihydroxy-dimethylpolysiloxane having a viscosity of 80,000 mPa.Math.s and 140 parts by weight of an α,ω-dihydroxy-dimethylpolysiloxane having a viscosity of 350,000 mPa.Math.s is used.

TABLE-US-00002 TABLE 2 Example 1 2 3 4 5 6 CE fraction 23% 17% 11% 7% 4% 13% Viscosity 608,100 624,000 563,300 546,000 582,400 589,200 η* (γ = 0.1%) Viscosity 72,000 76,100 64,200 65,800 67,700 71,300 η* (γ = 100%) Yield point 1410 1490 1510 1610 1750 1420 Skin-forming 14 15 18 17 17 14 time Early strength 30 30 30 30 30 30 Shore A 12 14 16 17 21 10 hardness Elongation at 660 580 490 450 360 790 break % Tensile 1.0 1.1 1.1 1.2 1.3 0.9 strength 100% strain 0.18 0.23 0.26 0.28 0.34 0.13 value Paste storage 28 d at 50° C. Skin-forming 17 16 20 15 19 15 time Climate storage vulcanizate 7 d at 70° C./95% rh Hardness 8 12 14 15 15 7 Elongation at 730 630 670 580 500 860 break Tensile 0.9 1.0 1.0 1.1 1.1 0.9 strength 100% strain 0.14 0.19 0.21 0.22 0.24 0.10 value Example 7 8 C1 C2 C3 C4 CE fraction 23% 23% 0% 23% 32% 0% Viscosity 586,500 645,700 729,000 603,100 583,400 860,200 η* (γ = 0.1%) Viscosity 69,200 81,600 86,000 79,300 68,500 124,000 η* (γ = 100%) Yield point 1380 1640 1700 1680 1410 1310 Skin-forming 15 15 17 15 15 13 time Early strength 30 30 60 30 30 60 Shore A 15 14 21 11 9 16 hardness Elongation at 580 610 310 650 870 480 break % Tensile 1.3 1.2 1.2 1.3 1.1 1.2 strength 100% strain 0.22 0.19 0.39 0.21 0.12 0.26 value Paste storage 28 d at 50° C. Skin-forming 13 15 20 20 19 17 time Climate storage vulcanizate 7 d at 70° C./95% rh Hardness 12 12 16 3 2 13 Elongation at 660 690 340 60 90 540 break Tensile 1.1 1.0 1.1 0.2 n.m 1.0 strength 100% strain 0.17 0.15 0.33 n.m n.m 0.18 value

[0195] The modulus of the materials of the invention can be adjusted across a wide range.

[0196] The stability of the inventive materials after climatic storage of the vulcanizates is evident from comparing inventive examples 7 and 8 with comparative example C2, and C3 with inventive example 6: whereas the initial properties are comparable, the elastomer properties such as hardness, tensile strength, elongation at break, and 100% strain value suffer a massive collapse in the case of the noninventive materials.

[0197] The improved working characteristics are evident from the lower viscosity η* at γ=0.1% and γ=100% in conjunction with high yield point.

[0198] The high vulcanization rate is evident from the short skin-forming times and the short early strengths.

[0199] The skin-forming times are stable (see table); the early strengths after aging of the pastes for 28 d at 50° C. are unchanged.