Curable condensation compounds based on alkoxy-functional polysiloxanes
Curable condensation compounds are obtainable by a reaction of non-end-equilibrated acetoxy group-bearing siloxanes with at least one alkoxy-functional polysiloxane, in the presence of a catalyst.
1 . A curable condensation compound, obtained by a reaction of:
acetoxy group-bearing siloxanes of formula (I):
wherein R=an alkyl radical having 1 to 4 carbon atoms and/or phenyl radical, and 1≤x≤500,
wherein the acetoxy group-bearing siloxanes of formula (I) have not been end-equilibrated,
with
at least one alkoxy-functional polysiloxane of the formula (II)
R 1 c Si(OR 2 ) d O (4-c-d)/2 Formula (II)
wherein c is not less than 0 to not more than 2, d is not less than 0 to not more than 4, and a sum total of c+d is less than 4,
R 1 is the same or different and is independently a linear or branched, saturated or else mono- or polyunsaturated or aromatic hydrocarbon radical, and
R 2 is an alkyl group consisting of 1 to 8 carbon atoms, and
in the presence of a catalyst.
2 . The condensation compound according to claim 1 , wherein the non-end-equilibrated acetoxy group-bearing siloxanes of formula (I) are obtainable by a reaction of linear α,ω-hydroxy group-bearing polysiloxanes with acetic anhydride.
3 . The condensation compound according to claim 1 , wherein the acetoxy group-bearing siloxanes of formula (I) have exclusively D units.
4 . The condensation compound according to claim 1 , wherein the acetoxy group-bearing siloxanes of formula (I) are α,ω-acetoxy group-bearing linear polydimethylsiloxanes.
5 . The condensation compound according to claim 1 , wherein in the at least one alkoxy-functional polysiloxane, R 1 =a methyl or phenyl radical.
6 . The condensation compound according to claim 1 , wherein a weight-average molecular weight of the at least one alkoxy-functional polysiloxane is 200 to 20,000 g/mol.
7 . The condensation compound according to claim 1 , wherein an alkoxy functionality of the at least one alkoxy-functional polysiloxane is from 50% to 3% by weight, based on a total mass of the at least one alkoxy-functional polysiloxane.
8 . The condensation compound according to claim 1 , wherein the catalyst is selected from the group consisting of tin diacetate, tin dioctoate, dibutyltin diacetylacetonate, dibutyltin dilaurate, tin tetraacetate, dibutyltin diacetate, dibutyltin dioctoate, dibutyltin dioleate, dimethoxydibutyttin, dimethyltin, dibutyltinbenzyl maleate, bis(triethoxysiloxy)dibutyltin, diphenyltin diacetate, dioctyltin dilaurate, dioctyltin dineodecanoate, tetraethoxytitanium, tetra-n-propoxytitanium, tetraisopropoxytitanium, tetra-n-butoxytitanium, tetraisobutoxytitanium, tetrakis(2-ethylhexoxy)titanium, diisopropoxybis(ethylacetoacetato)titanium, dipropoxybis(acetylacetonato)titanium, diisopropoxybis(acetylacetonato)titanium, dibutoxybis(acetylacetonato)titanium, trisopropoxyallyltitanium acetate, isopropoxyoctylene glycol-titanium oxide or bis(acetylacetonato)titanium oxide, lead diacetate, lead di-2-ethylhexanoate, lead dineodecanoate, lead tetraacetate, lead tetrapropionate, zinc acetylacetonate, zinc 2-ethylcaproate, zinc diacetate, bis(2-ethylhexanoyl)zinc, zinc dineodecanoate, zinc diundecenoate, zinc dimethacrylate, tetrakis(2-ethylhexanoyl)zirconium dichloride, tetrakis(methacryloyl)zirconium dichloride, cobalt diacetate, bismuth carboxylate, and bismuth triflate.
9 . The condensation compound according to claim 1 , wherein the reaction includes at least one crosslinker of formula (IV)
R 3 e Si(OR 4 ) f Formula (IV)
wherein e is not less than 0 to not more than 2, f is not less than 2 to not more than 4, and a sum total of e+f is 4,
R 3 =a saturated or unsaturated alkyl group consisting of 1 to 8 carbon atoms or an aromatic moiety having 6 to 20 carbon atoms, and
R 4 =an alkyl or acyl group consisting of 1 to 8 carbon atoms.
10 . The condensation compound according to claim 9 , wherein the at least one crosslinker is selected from the group consisting of methyltriacetoxysilane, ethyltriacetoxysilane, dimethyldiacetoxysilane, methyltrimethoxysilane, methyltriethoxysilane, vinyltimethoxysilane, vinyltriethoxysilane, tetramethoxysilane, tetraethoxysilane, phenyltrethoxysilane, phenyltrimethoxysilane, propyltimethoxysilane, propyltriethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, dimethoxyphenylmethylsilane, and diethoxyphenylmethylsilane.
11 . A process for preparing the condensation compound according to claim 1 , the process comprising:
reacting the non-end-equilibrated acetoxy group-bearing siloxanes of formula (I) with the at least one alkoxy-functional polysiloxane of the formula (II) in the presence of the catalyst.
12 . The process according to claim 11 , wherein a weight ratio of the acetoxy group-bearing siloxanes of formula (I) to the at least one alkoxy-functional polysiloxane of formula (II) is 1:99 to 99:1, based on an overall silicone matrix.
13 . The process according to claim 11 , wherein the catalyst is formed in situ or prior to the reaction.
14 . The process according to claim 11 , wherein the acetoxy group-bearing siloxanes of formula (I) have D units.
15 . The process according to claim 11 , wherein the acetoxy group-bearing siloxanes of formula (I) are non-end-equilibrated α,ω-acetoxy group-bearing linear polydimethylsiloxanes.
16 . The process according to claim 11 , wherein in the at least one alkoxy-functional polysiloxane, R 1 =a methyl or phenyl radical.
17 . The process according to claim 11 , wherein an alkoxy functionality of the at least one alkoxy-functional polysiloxane is from 50% to 3% by weight, based on a total mass of the at least one alkoxy-functional polysiloxane.
18 . The process according to claim 11 , wherein the catalyst is selected from the group consisting of tin diacetate, tin dioctoate, dibutytin diacetylacetonate, dibutyltin dilaurate, tin tetraacetate, dibutyltin diacetate, dibutyltin dioctoate, dibutyltin dioleate, dimethoxydibutyltin, dimethyltin, dibutyltinbenzyl maleate, bis(triethoxysiloxy)dibutyltin, diphenyltin diacetate, dioctyltin dilaurate, dioctyltin dineodecanoate, tetraethoxytitanium, tetra-n-propoxytitanium, tetraisopropoxytitanium, tetra-n-butoxytitanium, tetraisobutoxytitanium, tetrakis(2-ethylhexoxy)titanium, diisopropoxybis(ethylacetoacetato)titanium, dipropoxybis(acetylacetonato)titanium, diisopropoxybis(acetylacetonato)titanium, dibutoxybis(acetylacetonato)titanium, triisopropoxyallyltitanium acetate, isopropoxyoctylene glycol-titanium oxide or bis(acetylacetonato)titanium oxide, lead diacetate, lead di-2-ethylhexanoate, lead dineodecanoate, lead tetraacetate, lead tetrapropionate, zinc acetylacetonate, zinc 2-ethylcaproate, zinc diacetate, bis(2-ethylhexanoyl)zinc, zinc dineodecanoate, zinc diundecenoate, zinc dimethacrylate, tetrakis(2-ethylhexanoyl)zirconium dichloride, tetrakis(methacryloyl)zirconium dichloride, cobalt diacetate, bismuth carboxylate, and bismuth triflate.
19 . The process according claim 11 , wherein the condensation reaction is complete with respect to acetoxysiloxane/silane used.
20 . The process according to claim 11 , wherein the reaction includes at least one crosslinker of formula (IV)
R 3 e Si(OR 4 ) f Formula (IV)
wherein e is not less than 0 to not more than 2, f is not less than 2 to not more than 4, and a sum total of e+f is 4,
R 3 =a saturated or unsaturated alkyl group consisting of 1 to 8 carbon atoms or an aromatic moiety having 6 to 20 carbon atoms, and
R 4 =an alkyl or acyl group consisting of 1 to 8 carbon atoms.
21 . The process according to claim 20 , wherein the at least one crosslinker is selected from the group consisting of methyltriacetoxysilane, ethyltriacetoxysilane, dimethyldiacetoxysilane, methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, tetramethoxysilane, tetraethoxysilane, phenyltriethoxysilane, phenyltrimethoxysilane, propyltrimethoxysilane, propyltriethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, and dimethoxyphenylmethylsilane.
22 . The process according to claim 11 , wherein an acetic ester formed from the R 2 radical and the acetoxy group is removed during the reaction.
23 . The process according to claim 22 , wherein the acetic ester formed is removed from the reaction by distillation and/or optionally with application of an auxiliary vacuum.
24 . A method, comprising:
producing a coating with the curable condensation compound according to claim 1 .
25 . A coated product, having a coating comprising the condensation compound according to claim 1 .