COMPOSITION AND METHOD FOR PRODUCING SILICONE COMPOUNDS, AND USE THEREOF

Abstract

The invention relates to a composition and a method for producing moisture-crosslinking silicones with catalysis by at least two different catalysts A and B, a related process and the use of the composition, in particular, in sealants, adhesives, joint compounds or coating agents.

Claims

1. Composition, comprising at least one hydroxy-functionalized polyorganosiloxane compound, at least one crosslinker and at least two catalysts A and B, where the catalyst A is selected from the group of metal siloxane-silanol(ate) compounds; and catalyst B is selected from a group of catalysts that does not comprise metal siloxane-silanol(ate) compounds.

2. Composition, as claimed in claim 1, characterized in that the catalyst B is selected from the group of organometallic compounds.

3. Composition, as claimed in claim 1, characterized in that the catalyst B is selected from the group consisting of tetraalkyl titanates, such as tetramethyl titanate, tetraethyl titanate, tetra-n-propyl titanate, tetraisopropyl titanate, tetra-n-butyl titanate, tetraisobutyl titanate, tetra-sec-butyl titanate, tetraoctyl titanate, tetra(2-ethylhexyl)titanate, dialkyl titanates ((RO).sub.2TiO.sub.2, where R stands, for example, for isopropyl, n-butyl, isobutyl), such as isopropyl-n-butyl titanate; titanium acetylacetonate chelates, such as diisopropoxy bis(acetylacetonate)titanate, diisopropoxy bis(ethyl acetylacetonate)titanate, di-n-butyl bis(acetylacetonate)titanate, di-n-butyl bis(ethyl acetoacetate)titanate, triisopropoxide bis(acetylacetonate)titanate, zirconium tetraalkylates, such as zirconium tetraethylate, zirconium tetrabutylate, zirconium tetrabutyrate, zirconium tetrapropylate, zirconium carboxylates, such as zirconium diacetate; zirconium acetylacetonate chelates, such as zirconium tetra(acetylacetonate), tributoxyzirconium acetylacetonate, dibutoxyzirconium (bisacetylacetonate), aluminum trisalicylates, such as aluminum triisopropylate, aluminum sec-butylate; aluminum acetylacetonate chelates, such as aluminum tris(acetylacetonate) and aluminum tris(ethyl acetylacetonate); organotin compounds, such as dibutyltin dilaurate (DBTL), dibutyltin maleate, dibutyltin diacetate, tin(II) 2-ethylhexanoate (tin octoate), tin naphthenate, dimethyltin dineodecanoate, dioctyltin dineodecanoate, dimethyltin dioleate, dioctyltin dilaurate, dimethyltin mercaptides, dibutyltin mercaptides, dioctyltin mercaptides, dibutyltin dithioglycolate, dioctyltin glycolate, dimethyltin glycolates; a solution of dibutyltin oxide, reaction products of zinc salts and organic carboxylic acids (carboxylates), such as zinc(II) 2-ethylhexanoate or zinc(II) neodecanoate, mixtures of bismuth and zinc carboxylates, reaction products of calcium salts and organic carboxylic acids (carboxylates), such as calcium bis(2-ethylhexanoate) or calcium neodecanoate, reaction products of sodium salts and organic carboxylic acids (carboxylates), such as sodium (2-ethylhexanoate) or sodium neodecanoate, mixtures of calcium and sodium carboxylates, reaction products of bismuth salts and organic carboxylic acids, such as bismuth(III) tris(2-ethylhexanoate) and bismuth(III) tris(neodecanoate) as well as bismuth complex compounds, organolead compounds, such as lead octylate, organovanadium compounds or mixtures thereof; selected preferably from bismuth, zinc, aluminum, calcium, sodium, and/or zirconium carboxylates; selected most preferably from dibutyltin dilaurate (DBTL), tin(II) 2-ethylhexanoate (tin octoate), zinc(II) 2-ethylhexanoate, zinc(II) neodecanoate (tin neodecanoate), bismuth(III) tris(2-ethylhexanoate), bismuth(III) tris(neodecanoate) (bismuth neodecanoate), titanium tetraisopropylate, titanium tetrabutylate, aluminum sec-butylate, zirconium tetraisopropylate, zirconium tetrabutylate, calcium bis(2-ethylhexanoate), sodium (2-ethylhexanoate) or mixtures thereof; extreme preference being given to bismuth(III) tris(neodecanoate), bismuth(III) tris(2-ethylhexanoate) or mixtures thereof; bismuth(III) tris(neodecanoate being extremely preferred.

4. Composition, as claimed in claim 1, characterized in that the hydroxy-functionalized polyorganosiloxane compound is an α,ω-dihydroxypolyorganosiloxane.

5. Composition, as claimed in claim 4, characterized in that the α,ω-dihydroxypolyorganosiloxane has a kinematic viscosity, according to DIN 53019-1:2008-09, of at least 10,000 cSt, preferably at least 20,000 cSt, more preferably at least 50,000 cSt, most preferably a kinematic viscosity of about 80,000 cSt.

6. Composition, as claimed in claim 1, characterized in that the crosslinker is selected from the group consisting of oxime crosslinkers, such as vinyl tris(2-pentanone oxime)silane, ethyl tris(2-propanone oxime)silane, methyl tris(2-pentanone oxime)silane, vinyl tris(2-propanone oxime)silane, methoxyvinyl di(2-propanone oxime)silane, dimethoxyvinyl (2-propanone oxime)silane, methyl tris(2-butanone oxime)silane, phenyl tris(2-butanone oxime)silane, vinyl tris(2-butanone oxime)silane and tetra(2-butanone oxime)silane or mixtures thereof; acetate crosslinkers, such as methyltriacetoxysilane, ethyltriacetoxysilane, propyltriacetoxysilane or vinyltriacetoxysilane or mixtures thereof; lactate crosslinkers, such as tris(ethyl lactate)methylsilane or tris(ethyl lactate)vinylsilane or mixtures thereof; salicylate crosslinkers, such as tris(2-ethylhexyl salicylate)vinylsilane, tris(2-ethylhexyl salicylate)methylsilane, tris(2-ethylhexyl salicylate)propylsilane or mixtures thereof; or a mixture of all of the aforementioned crosslinkers.

7. Composition, as claimed in claim 1, characterized in that the crosslinker is selected from the group consisting of oxime crosslinkers, such as vinyl tris(2-pentanone oxime)silane, ethyl tris(2-propanone oxime)silane, methyl tris(2-pentanone oxime)silane, vinyl tris(2-propanone oxime)silane, methoxyvinyl di(2-propanone oxime)silane, dimethoxyvinyl (2-propanone oxime)silane, methyl tris(2-butanone oxime)silane, phenyl tris(2-butanone oxime)silane, vinyl tris(2-butanone oxime)silane and tetra(2-butanone oxime)silane or mixtures thereof; acetate crosslinkers, such as methyltriacetoxysilane, ethyltriacetoxysilane, propyltriacetoxysilane or vinyltriacetoxysilane or mixtures thereof; or a mixture of all of the aforementioned crosslinkers.

8. Composition, as claimed in claim 1, characterized in that the crosslinker is selected from the group consisting of oxime crosslinkers, such as vinyl tris(2-pentanone oxime)silane, ethyl tris(2-propanone oxime)silane, methyl tris(2-pentanone oxime)silane, vinyl tris(2-propanone oxime)silane, methoxyvinyl di(2-propanone oxime)silane, dimethoxyvinyl (2-propanone oxime)silane, methyl tris(2-butanone oxime)silane, phenyl tris(2-butanone oxime)silane, vinyl tris(2-butanone oxime)silane and tetra(2-butanone oxime)silane or mixtures thereof.

9. Composition, as claimed in claim 1, characterized in that the metal siloxane-silanol(ate) compound has the general formula R*.sub.qSi.sub.rO.sub.sM.sub.t, where each R* is selected, independently of each other, from the group consisting of optionally substituted C1 to C20 alkyl, optionally substituted C3 to C6 cycloalkyl, optionally substituted C2 to C20 alkenyl, optionally substituted C6 to C10 aryl, —OH and —O—(C1 to C10 alkyl), each M being selected, independently of each other, from the group consisting of s and p block metals, d and f block transition metals, lanthanide and actinide metals and semimetals, in particular, from the group consisting of metals of the 1st, 2nd, 3rd, 4th, 5th, 8th, 10th and 11th subgroup and metals of the 1st, 2nd, 3rd, 4th and 5th main group, preferably from the group consisting of Na, Zn, Sc, Nd, Ti, Zr, Hf, V, Fe, Pt, Cu, Ga, Sn and Bi, particularly preferably from the group consisting of Zn, Ti, Zr, Hf, V, Fe, Sn and Bi, q is an integer from 4 to 19, r is an integer from 4 to 10, s is an integer from 8 to 30, and t is an integer from 1 to 8.

10. Composition, as claimed in claim 9, characterized in that the metal siloxane-silanol(ate) compound is a metal silsesquioxane of the structure (IV), ##STR00027## where X.sup.4 is selected from the group selected from the group consisting of metals of the 1st, 2nd, 3rd, 4th, 5th, 8th, 10th and 11th subgroup and metals of the 1st, 2nd, 3rd, 4th and 5th main group, preferably from the group consisting of Na, Zn, Sc, Nd, Ti, Zr, Hf, V, Fe, Pt, Cu, Ga, Sn and Bi, particularly preferably from the group consisting of Zn, Ti, Zr, Hf, V, Fe, Sn and Bi, most preferably from the group consisting of Ti and Sn, Ti being most preferred, and X.sup.4 is linked to OR, where R is selected from the group consisting of H, methyl, ethyl, propyl, butyl, octyl, isopropyl and isobutyl; Z.sup.1, Z.sup.2 and Z.sup.3 each denote, independently of each other, C1 to C20 alkyl, C3 to C8 cycloalkyl, C2 to C20 alkenyl and C5 to C10 aryl; in particular, are selected from the group consisting of methyl, ethyl, propyl, isopropyl, butyl, isobutyl, hexyl, heptyl, octyl, vinyl, allyl, butenyl and phenyl, and benzyl; and R.sup.1, R.sup.2, R.sup.3 and R.sup.4 each denote, independently of each other, C1 to C20 alkyl, C3 to C8 cycloalkyl, C2 to C20 alkenyl, and C5 to C10 aryl, in particular, are selected from the group consisting of methyl, ethyl, propyl, isopropyl, butyl, isobutyl, hexyl, heptyl, octyl, vinyl, allyl, butenyl and phenyl, and benzyl.

11. Composition, as claimed in claim 10, characterized in that the metal siloxane-silanol(ate) compound is a metal silsesquioxane of the structure (IVb), ##STR00028## where X.sup.4 is selected from the group consisting of metals of the 1st, 2nd, 3rd, 4th, 5th, 8th, 10th and 11th subgroup and metals of the 1st, 2nd, 3rd, 4th and 5th main group, preferably from the group consisting of Na, Zn, Sc, Nd, Ti, Zr, Hf, V, Fe, Pt, Cu, Ga, Sn and Bi; particularly preferably from the group consisting of Zn, Ti, Zr, Hf, V, Fe, Sn and Bi; most preferably from the group consisting of Ti (and is, therefore, heptaisobutyl POSS titanium(IV) ethoxide (TiPOSS)) and Sn (and is, therefore, heptaisobutyl POSS tin(IV) ethoxide (SnPOSS)), and most preferably Ti (and is, therefore, heptaisobutyl POSS titanium(IV) ethoxide (TiPOSS)).

12. Composition, as claimed in claim 1, characterized in that the metal siloxane-silanol(ate) compound is present in a molar concentration in the range of 0.000001 to 0.01 mol/kg, in particular, 0.00005 to 0.005 mol/kg or 0.00007 to 0.001 mol/kg, in each case based on the total weight of the composition.

13. Composition, as claimed in claim 1, characterized in that the metal siloxane-silanol(ate) compound is present in a proportion by weight of 0.001 to 0.5%, preferably 0.006 to 0.1%.

14. Composition, as claimed in claim 1, characterized in that the crosslinker is selected from the group consisting of oxime crosslinkers, such as vinyl tris(2-pentanone oxime)silane, methyl tris(2-pentanone oxime)silane, vinyl tris(2-propanone oxime)silane, methoxyvinyl di(2-propanone oxime)silane and dimethoxyvinyl (2-propanone oxime)silane or mixtures thereof; or acetate crosslinkers, such as methyltriacetoxysilane; and catalyst A is selected from the group consisting of mononuclear metallized silsesquioxanes of the structural formula (IV) or mixtures thereof; and catalyst B is selected from the group consisting of dibutyltin dilaurate (DBTL), tin(II) 2-ethylhexanoate (tin octoate), zinc(II) 2-ethylhexanoate, zinc(II) neodecanoate, calcium bis(2-ethylhexanoate), sodium (2-ethylhexanoate), bismuth(III) tris(2-ethylhexanoate), bismuth(III) tris(neodecanoate), titanium tetraisopropylate, titanium tetrabutylate, aluminum sec-butylate, zirconium tetraisopropylate, zirconium tetrabutylate or mixtures thereof.

15. Composition, as claimed in claim 1, characterized in that the catalysts A and B are present in a relative ratio between 1:10 and 10:1; more preferably the catalysts A and B are present in a relative ratio between 1:8 and 8:1; particularly preferably the catalysts A and B are present in a relative ratio between 1:5 and 5:1, even more preferably the catalysts A and B are present in a relative ratio between 1:2 to 2:1; most preferably in a relative ratio of 0.9:1.1 to 1.1:0.9; extremely preferably in a relative ratio of 1:1, based on percent by weight.

16. Composition, as claimed in claim 15, characterized in that catalyst A is TiPOSS or SnPOSS; and catalyst B is selected from the group consisting of bismuth(III) tris(neodecanoate), dibutyltin dilaurate (DBTL), zinc(II) 2-ethylhexanoate, zirconium tetraisopropylate, zirconium tetrabutylate or mixtures thereof; catalyst A is particularly preferably TiPOSS; and catalyst B is bismuth(III) tris(neodecanoate).

17. Method for producing a composition, wherein said method comprises the following process steps: a. providing a composition comprising i. at least one α,ω-dihydroxypolyorganosiloxane, which has a kinematic viscosity, according to DIN 53019-1:2008-09, of at least 50,000 cSt, ii. a catalyst A, where the catalyst is TiPOSS or SnPOSS, TiPOSS being preferred, iii. a catalyst B, where the catalyst is dibutyltin dilaurate (DBTL), tin(II) 2-ethylhexanoate (tin octoate), zinc(II) 2-ethylhexanoate, zinc(II) neodecanoate, bismuth(III) tris(2-ethylhexanoate), bismuth(III) tris(neodecanoate), titanium tetraisopropylate, titanium tetrabutylate, aluminum sec-butylate, zirconium tetraisopropylate, zirconium tetrabutylate or mixtures thereof, bismuth(III) tris(neodecanoate) being preferred, iv. at least one crosslinker selected from the group consisting of oxime crosslinkers, such as vinyl tris(2-pentanone oxime)silane, methyl tris(2-pentanone oxime)silane, vinyl tris(2-propanone oxime)silane, methoxyvinyl di(2-propanone oxime)silane and dimethoxyvinyl (2-propanone oxime)silane or mixtures thereof; or acetate crosslinkers, such as methyltriacetoxysilane, b. mixing the composition, provided in a., using mechanical and/or thermal energy.

18. Composition, obtainable by a method, as claimed in claim 16.

19. Sealant formulation comprising the following components: at least one hydroxy-functionalized polyorganosiloxane compound, at least one crosslinker, at least two catalysts A and B, at least one plasticizer, at least one filler and at least one adhesion promoter.

20. Use of at least two catalysts A and B, as claimed in claim 2, for the production of silicone compositions having a Shore A hardness of <50, preferably <25, particularly preferably ≤15.

21. Use, as claimed in claim 20, for the production of silicone compounds having an elongation at break, according to DIN 53504:2017-03, S2 test geometry, of at least 150%, preferably at least 200%, particularly preferably at least 250%.

22. Sealants after the use of at least two catalysts A and B, as claimed in claim 2, wherein the sealants have a curing time, the period of time, in which a 4 mm thick polymer test specimen is no longer gel-like internally and has hardened completely, of a maximum of 48 hours, preferably a maximum of 36 hours, particularly preferably a maximum of 24 hours.

Description

EXAMPLES

Example I

[0430] The catalytic effect of TiPOSS on the moisture-induced polymerization reaction of hydroxy-functionalized α,ω-dihydroxypolyorganosiloxanes with crosslinkers to form silicone polymers is well-known. Surprisingly, however, it has been found that the moisture-induced polymerization reaction of α,ω-dihydroxypolyorganosiloxanes with crosslinkers that have hydrolyzable leaving groups can be accelerated by using a mixture of heptaisobutyl POSS titanium(IV) ethoxide (TiPOSS) and catalysts based on titanium, bismuth, zinc, aluminum, zirconium and tin. Surprisingly it was found that the silicone polymers, which are produced using catalyst mixtures of TiPOSS and organometallic compounds, such as bismuth(III) tris(neodecanoate), have advantageous properties during processing and in the product properties. In essence, this means a larger processing window with generally faster curing. In addition, soft products become available that have a significantly increased stretch/elasticity.

[0431] The study of the activity of the catalyst mixtures of TiPOSS and the organometallic compounds consisting of titanium, bismuth, zinc, aluminum, zirconium and tin for curing the silicone compounds was conducted in comparison with the curing process with the use of just TiPOSS alone. For this purpose basic RTV-1 silicone formulations were used as an example, where said formulations were composed of an α,ω-dihydroxypolydimethylsiloxane (80,000 cSt) and a polydimethylsiloxane plasticizer (100 cSt). The crosslinkers that were used included oxime-releasing silanes (vinyl tris(2-pentanone oxime)silane and methyl tris(2-pentanone oxime)silane), a mixture of vinyl tris(2-propanone oxime)silane, methoxyvinyl di(2-propanone oxime)silane, dimethoxyvinyl (2-propanone oxime)silane as well as an acetate-releasing silane, methyltriacetoxysilane.

[0432] Then the addition of adhesion promoters (for example, 3-aminopropyltrimethoxysilane) and a fumed silica was initially omitted, in order to rule out the influence of these compounds on the curing speed. The impact of adhesion promoter and silica on the curing process was verified by means of an illustrative formulation using a catalyst mixture of TiPOSS and bismuth(III) tris(neodecanoate).

[0433] Experimental Part:

[0434] Raw materials used to produce the silicone polymers SP:

α,ω-dihydroxypolydimethylsiloxane, 80,000 cSt (CAS 70131-67-8)
polydimethylsiloxane, 100 cSt, Sigma-Aldrich (CAS 63148-62-9)
vinyl tris(2-pentanone oxime)silane, OS 1600, Nitrochemie (CAS 37859-55-5)
methyl tris(2-pentanone oxime)silane, OS 2600, Nitrochemie (CAS 58190-62-8)
mixture of vinyl tris(2-propanone oxime)silane, methoxyvinyl di(2-propanone oxime)silane,
dimethoxyvinyl (2-propanone oxime)silane, LM 100, Nitrochemie (CAS 795571-44-1) methyltriacetoxysilane, TCI Chemicals (CAS 4253-34-3)
fumed silica, 200 m.sup.2/g, Evonik (CAS 112945-52-5)
TiPOSS, 20%, dissolved in Hexamoll DINCH, BASF (CAS 166412-78-8, DINCH)
dibutyltin dilaurate, DBTL; Kosmos 19, Evonik (CAS 7758-7)
bismuth neodecanoate, Kat 315EU, Borchers (CAS 34364-26-6)
zinc(II) 2-ethylhexanoate, Kat 22, Borchers (CAS 301-10-0)
titanium tetraisopropylate, TCI Chemicals (CAS 546-68-9)
titanium tetrabutylate, TCI Chemicals (CAS 5593-70-4)
aluminum tri-sec-butylate, TCI Chemicals (CAS 2269-22-9)
zirconium tetraisopropylate, TCI Chemicals (CAS 23519-77-9)
zirconium tetrabutylate, TCI Chemicals (CAS 1071-76-7)
3-aminopropyltrimethoxysilane (AMMO), TCI Chemicals (CAS 13822-56-5)

Production of the Necessary Silicone Compounds SP1 to SP5, SP16 to SP39 (Pentanone Oxime Crosslinker) and SP6 to SP10 (Propanone Oxime Crosslinker) for the Curing Tests

[0435] α,ω-dihydroxypolydimethylsiloxane 80,000 cSt and polydimethylsiloxane 100 cSt were mixed with the crosslinkers vinyl tris(2-pentanone oxime)silane and methyl tris(2-pentanone oxime)silane (SP1 to SP5, SP16 to SP39) or a mixture of vinyl tris(2-propanone oxime)silane, methoxyvinyl di(2-propanone oxime)silane and dimethoxyvinyl (2-propanone oxime)silane (SP6 to SP10) in the absence of air.

Production of the Necessary Silicone Compounds SP11 to SP15 (Acetate Crosslinker) for the Curing Tests

[0436] α,ω-dihydroxypolydimethylsiloxane 80,000 cSt and polydimethylsiloxane 100 cSt were mixed in the absence of air. TiPOSS and the specified amount of mixture of TiPOSS and bismuth(III) tris(neodecanoate) as well as TiPOSS and DBTL, according to Table 1, were incorporated by stirring into the compound obtained.

Testing of the Curing Characteristics of the Silicone Compounds SP1 to SP10, SP16 to SP35 and SP36 to SP39

[0437] The testing of the curing characteristics of the silicone compounds SP1 to SP10, SP16 to SP35 and SP36 to SP39 was conducted by determining the skin formation time, the tack-free time TF and the curing time on ˜4 mm thick test specimens at 23° C./50% relative humidity. The test specimens were formulated with TiPOSS, DBTL, bismuth neodecanoate, zinc(II) 2-ethylhexanoate, titanium tetraisopropylate, titanium tetrabutylate, aluminum tri-sec-butylate, zirconium tetraisopropylate, zirconium tetrabutylate and mixtures of TiPOSS and the aforementioned catalysts, according to Table 1, Table 2 and Table 3, and then cured.

Testing of the Curing Characteristics of the Silicone Compounds SP11 to SP15

[0438] The testing of the curing characteristics of the silicone compounds SP11 to SP15 was conducted by determining the skin formation time, the tack-free time TF and the curing time on ˜4 mm thick test specimens at 23° C./50% relative humidity. The test specimens were mixed with the appropriate amount of methyltriacetoxysilane crosslinker and cured.

Production and Testing of the Curing Characteristics of the Silicone Compounds SP40 to SP43

[0439] α,ω-dihydroxypolydimethylsiloxane 80,000 cSt and polydimethylsiloxane 100 cSt were mixed with the crosslinkers vinyl tris(2-pentanone oxime)silane and methyl tris(2-pentanone oxime)silane (SP40 and SP41) or a mixture of vinyl tris(2-propanone oxime)silane, methoxyvinyl di(2-propanone oxime)silane and dimethoxyvinyl (2-propanone oxime)silane (SP42 to SP43). Then silica, TiPOSS and the specified amount of mixture of TiPOSS and bismuth(III) tris(neodecanoate) and adhesion promoter were added and mixed. The silicone polymers, which were obtained, were cured at 23° C./50% relative humidity; and the skin formation time, the tack-free time TF and the curing time were determined on ˜4 mm thick test specimens.

TABLE-US-00001 TABLE 1 Components of the Silicone Compounds SP1 to SP15, Curing Characteristics at 23° C./50% Relative Humidity and Technical Specifications Pentanone Oxime Crosslinker Propanone Oxime crosslinker Component SP1 SP2 SP3 SP4 SP5 SP6 SP7 SP8 1α,ω- 62.1 62 62.1 62.1 62.1 62.1 62 62 dihydroxydimethyl- polysiloxane 80,000 cSt polydimethylsiloxane 33.4 33 33.4 33.4 33.4 33.9 34 34 100 cSt vinyl tris(2-pentanone 2.2 2.2 2.2 2.2 2.2 — — — oxime)silane methyl tris(2-pentanone 2.2 2.2 2.2 2.2 2.2 — — — oxime)silane mixture of vinyl — — — — — 4 4 4 tris(2-propanone oxime)silane; methoxyvinyl di(2-propanone oxime)silane; dimethoxyvinyl (2-propanone oxime)silane methyltriacetoxysilane — — — — — — — — TiPOSS 0.05 0.1 0.05 0.05 0.05 0.05 0.1 0.05 DBTL — — 0.05 — — — — 0.05 bismuth neodecanoate — — — 0.05 0.083 — — — skin formation 150 100 60 120 100 300 180 75 time [min].sup.1 tack-free time [min].sup.2 360 300 150 330 300 540 480 180 curing time [h].sup.3 24 24 20 20 16 48 48 22 Shore A 10 10 6 6 5 8 8 8 [after 7 days].sup.4 tensile strength [kPa].sup.5 — 160 — — 130 — 180 — elongation at break [%].sup.5 — 250 — — 400 — 320 — Propanone Oxime crosslinker Acetate Oxime Crosslinker Component SP9 SP10 SP11 SP12 SP13 SP14 SP15 1α,ω- 62.1 62.1 62.1 62.1 62.1 62.1 62.1 dihydroxydimethyl- polysiloxane 80,000 cSt polydimethylsiloxane 33.9 33.9 33.9 33.9 33.9 33.9 33.9 100 cSt vinyl tris(2-pentanone — — — — — — — oxime)silane methyl tris(2-pentanone — — — — — — — oxime)silane mixture of vinyl 4 4 — — — — — tris(2-propanone oxime)silane; methoxyvinyl di(2-propanone oxime)silane; dimethoxyvinyl (2-propanone oxime)silane methyltriacetoxysilane — — 4 4 4 4 4 TiPOSS 0.05 0.05 0.0025 0.005 0.005 0.0025 0.0025 DBTL — — — — 0.005 — — bismuth neodecanoate 0.05 0.083 — — — 0.0025 0.004 skin formation 240 180 17 12 10 12 12 time [min].sup.1 tack-free time [min].sup.2 540 480 80 60 50 80 60 curing time [h].sup.3 30 24 30 30 24 24 22 Shore A 4 3 7 6 7 6 4 [after 7 days].sup.4 tensile strength [kPa].sup.5 — 120 — 113 — — 105 elongation at break [%].sup.5 — 450 — 300 — — 325 — not determined .sup.1Period of time, during which the polymer surface is irreversibly lifted by touching it lightly with a wooden spatula. .sup.2Period of time, during which the polymer surface has no tendency to stick after touching it lightly with a wooden spatula. .sup.3Period of time, during which a 4 mm thick polymer test specimen is no longer gel-like internally and has completely hardened. .sup.4ASTM D2240-15 .sup.5Based on DIN 53504: 2017-03, S2 test geometry

TABLE-US-00002 TABLE 2 Components of the Silicone Compounds SP16 to SP35, Curing Characteristics at 23° C./50% Relative Humidity Component SP16 SP17 SP18 SP19 SP20 SP21 SP22 SP23 SP24 SP25 SP26 SP27 SP28 SP29 SP30 SP31 SP32 SP33 SP34 SP35  1 α,ω 62.1 62.1 62.1 62.1 62.1 62.1 62.1 62.1 62.1 62.1 62.1 62.1 62.1 62.1 62.1 62.1 62.1 62.1 62.1 62.1 dihydroxydimethyl- polysiloxane 80,000 cSt  2 polydimethylsiloxane 33.4 33.4 33.4 33.4 33.4 33.4 33.4 33.4 33.4 33.4 33.4 33.4 33.4 33.4 33.4 33.4 33.4 33.4 33.4 33.4 100 cSt  3 vinyl tris(2- 2.2 2.2 2.2 2.2 2.2 2.2 2.2 2.2 2.2 2.2 2.2 2.2 2.2 2.2 2.2 2.2 2.2 2.2 2.2 2.2 pentanone oxime)silane  4 methyl tris(2- 2.2 2.2 2.2 2.2 2.2 2.2 2.2 2.2 2.2 2.2 2.2 2.2 2.2 2.2 2.2 2.2 2.2 2.2 2.2 2.2 pentanone oxime)silane  5 TiPOSS — — — — — — — — 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05  6 DBTL 0.1 — — — — — — — — — — — — — — — — — — —  7 bismuth — 0.1 — — — — — — — — — — — — — — — — — — neodecanoate  8 zinc 2-ethylhexanoate — — 0.01 — — — — — 0.05 0.083 — — — — — — — — — —  9 titanium — — — 0.01 — — — — — — 0.05 0.083 — — — — — — — — tetraisopropylate 10 titanium — — — — 0.1 — — — — — — — 0.05 0.083 — — — — — — tetrabutylate 11 aluminum — — — — — 0.1 — — — — — — — — 0.05 0.083 — — — — tri-sec-butylate 12 zirconium — — — — — — 0.1 — — — — — — — — — 0.005 0.083 — — tetrabutylate 13 ziroconium — — — — — — — 0.1 — — — — — — — — — — 0.05 0.083 tetrobutylate 14 skin 50 100 100 90 100 120 220 230 120 90 90 90 100 90 100 90 140 130 130 130 formation time [min].sup.1 15 tack-free time 80 300 260 250 320 320 — — 225 180 250 250 240 225 260 240 300 300 300 300 [min].sup.2 16 curing time [h].sup.3 28 23 24 24 22 21 23 23 22 24 24 24 24 20 24 22 24 24 24 24 17 Shore A 5 5 7 7 8 7 7 7 7 8 9 7 8 8 9 8 7 8 8 8 [after 7 days].sup.4 .sup.1 to 4See footnote to Table 1

[0440] Table 3 describes the curing of silicone polymers comprising catalyst systems that have, in addition to TiPOSS and DBTL, a third metal catalyst component (SP36 to SP39). The third catalyst component, used for this purpose, was bismuth neodecanoate, titanium tetrabutylate, aluminum tri-sec-butylate and zirconium tetrabutylate, since they show increased catalytic activity as individual catalysts. Here, too, it can be noted, in general, that the skin formation time, the tack-free time and the curing time are reduced. However, the result is not an extended processing window.

TABLE-US-00003 TABLE 3 Components of the Silicone Compounds SP36 to SP39, Curing Characteristics at 23° C./50% Relative Humidity Component SP36 SP37 SP38 SP39 1 α,ω-dihydroxydimethylpolysiloxane 80,000 cSt 62.1 62.1 62.1 62.1 2 polydimethylsiloxane 100 cSt 33.4 33.4 33.4 33.4 3 vinyl tris(2-pentanone oxime)silane 2.2 2.2 2.2 2.2 4 methyl tris(2-pentanone oxime)silane 2.2 2.2 2.2 2.2 5 TiPOSS 0.05 0.05 0.05 0.05 6 DBTL 0.025 0.025 0.025 0.025 7 bismuth neodecanoate 0.025 — — 0.025 8 titanium tetrabutylate — 0.025 — — 9 aluminum tri-sec-butylate — — 0.025 — 10 zirconium tetrabutylate — — — 0.025 11 skin formation time [min].sup.1 90 60 90 100 12 tack-free time [min].sup.2 210 180 200 220 13 curing time [h].sup.3 24 20 20 22 14 Shore A [after 7 days].sup.4 10 7 6 4 .sup.1 to 4See footnote to Table 1

[0441] Table 4 lists the curing characteristics and the technical specifications of industry standard silicone polymer formulations (including sealants) that comprise silica and adhesion promoter, in addition to the components of the formulations specified in the Tables 1 to 3, SP2, SP5, SP7 and SP10. In these cases faster curing of the TiPOSS/bismuth(III) tris(neodecanoate) could also be determined. Softer products are obtained with simultaneously improved elongation properties.

TABLE-US-00004 TABLE 4 Curing Characteristics and Technical Specifications of Exemplary Silicone Formulations, determined at 23° C./50% Relative Humidity Component SP40 SP41 SP42 SP43 1 α,ω-dihydroxydimethylpolysiloxane 80,000 cSt 56.1 56.1 62.1 62.1 2 polydimethylsiloxane 100 cSt 33.4 33.4 33.9 33.9 3 vinyl tris(2-pentanone oxime)silane 2.2 2.2 — — 4 methyl tris(2-pentanone oxime)silane 2.2 2.2 — — 5 mixture of vinyl tris(2-propanone oxime)silane; — — 4 4 methoxyvinyl di(2-propanone oxime)silane; dimethoxyvinyl (2-propanone oxime)silane 6 silica 200 m.sup.2/g 5 5 5 5 7 3-aminopropyltrimethoxysilane 1 1 1 1 8 TiPOSS 0.1 0.05 0.1 0.05 9 bismuth neodecanoate — 0.083 — 0.083 10 skin formation time [min].sup.1 90 90 180 180 11 tack-free time [min].sup.2 280 280 450 420 12 curing time [h].sup.3 22 16 24 20 13 Shore A [after 7 days].sup.4 10 7 6 4 14 tensile strength [kPa].sup.5 250 250 320 300 15 elongation at break [%].sup.5 375 425 600 700 .sup.1 to 4See footnote to Table 1

[0442] As can be seen from above, the user has the following advantages, when silicone polymers, comprising TiPOSS, are catalytically modified with the additional use of metal catalysts, such as bismuth neodecanoate, zinc(JJ) 2-ethylhexanoate, titanium tetraisopropylate, titanium tetrabutylate, aluminum tri-sec-butylate, zirconium tetraisopropylate, zirconium tetrabutylate or dibutyltin dilaurate:

1. The further addition of bismuth(III) tris(neodecanoate) causes faster curing or, more specifically, complete hardening of the silicone polymers. The skin formation time and the tack-free time are not as accelerated as much as when TiPOSS is added. This means a larger processing window, since the polymers can still be manipulated in the range of the skin formation time.
2. With the additional use of bismuth neodecanoate, significantly softer products are obtained, which also have a significantly higher level of elongation at break. This is particularly advantageous in applications, where components, which move a lot or in opposite directions, have to be sealed, glued or connected.
3. The additional addition of dibutyltin dilaurate to silicone polymer blends, which comprise TiPOSS, results in faster curing or, more specifically, complete hardening of the silicone polymers than with the use of just TiPOSS alone.
4. The use of metal catalysts, such as zinc(II) 2-ethylhexanoate, titanium tetraisopropylate, titanium tetrabutylate, aluminum tri-sec-butylate, zirconium tetraisopropylate and zirconium tetrabutylate, in a mixture with TiPOSS is suitable for covering the curing characteristics, known from the sole use of TiPOSS in silicone polymers, to their full extent.

CONCLUSION

[0443] The skin formation time, the tack-free time and the curing time in silicone polymer systems that are produced with a pentanone oxime crosslinker (SP1), propanone oxime crosslinker (SP6) or acetoxy crosslinker (SP11) using TiPOSS as a catalyst are listed in Table 1. Further addition of TiPOSS to SP1, SP6 (0.05 parts by weight, respectively) or SP11 (0.0025 parts by weight) to initiate, for example, faster curing characteristics (SP2, SP7 and SP12) leads to a reduction in the skin formation and tack-free time, the curing time being otherwise unchanged.

[0444] The curing characteristics of corresponding silicone polymer systems, which, in analogy to SP2, are produced using exclusively the metal catalysts dibutyltin dilaurate, bismuth neodecanoate, zinc(II) 2-ethylhexanoate, titanium tetraisopropylate, titanium tetrabutylate, aluminum tri-sec-butylate, zirconium tetraisopropylate and zirconium tetrabutylate SP16 to SP23, are shown in Table 2. This table shows that silicone polymers using bismuth(III) tris (neodecanoate) (SP17), titanium tetrabutylate (SP20), aluminum tri-sec-butylate and zirconium tetrabutylate lead to faster curing, with comparatively the same or longer time for the skin formation and tack-free time. The DBTL-catalyzed silicone polymer (SP16) exhibits a faster skin formation time and tack-free time, compared to SP2, with a slower curing time.

[0445] The curing characteristics of silicone polymers, based on metal catalyst mixtures of TiPOSS and dibutyltin dilaurate, bismuth neodecanoate, zinc(II) 2-ethylhexanoate, titanium tetraisopropylate, titanium tetrabutylate, aluminum tri-sec-butylate, zirconium tetraisopropylate and zirconium tetrabutylate, are listed in SP3 to SP5, S8 to SP10, SP24 to SP35. On the whole, the addition of DBTL to SP1, SP6 (0.05 parts by weight) or SP11 (0.0025 parts by weight) results in accelerated curing characteristics, with a comparatively shortened curing time (SP3, SP8 and SP13). Particularly significant is the addition of bismuth(III) tris(neodecanoate) to SP1, SP6 (0.05 parts by weight) or SP11 (0.0025 parts by weight). Compared to TiPOSS and all of the other tested TiPOSS/metal catalyst mixtures, the result of such an addition is a smaller reduction in the skin formation and tack-free time, with a significant reduction in the curing time (SP4, SP9 and SP14). On the whole, it is apparent that the curing characteristics can be controlled over a wide range by means of the catalyst mixtures, composed of TiPOSS and dibutyltin dilaurate, bismuth neodecanoate, zinc(II) 2-ethylhexanoate, titanium tetraisopropylate, titanium tetrabutylate, aluminum tri-sec-butylate, zirconium tetraisopropylate and zirconium tetrabutylate, mentioned in Table 1 and Table 2.

[0446] A further increase in the amount of bismuth neodecanoate in SP5, SP9 (0.033 parts by weight) and SP15 (0.0015 parts by weight) results in a further shortening of the skin formation and tack-free times. A comparison with SP2, SP7 and SP12 shows that these values are on the same level, with significantly shorter curing times for SP5, SP10 and SP15. In addition to the aforementioned curing characteristics, these polymers are significantly softer and also have a significantly higher level of stretch (particularly pronounced in systems that were obtained on the basis of oxime crosslinkers (SP5 and SP 10)).