CROSSLINKABLE COMPOSITIONS BASED ON ORGANOSILICON COMPOUNDS

Abstract

A crosslinkable composition is based on organosilicon compounds that include

(A) organopolysiloxanes of the formula (I), the formula (I) being (R.sup.7O).sub.3-aSiR.sup.3.sub.aO(SiR.sup.4.sub.2O).sub.nSiR.sup.3.sub.a(OR.sup.7).sub.3-a, and
(B) siloxanes of the formula (II), the formular (II) being

##STR00001##

with the proviso that the sum of all x in formula (II) is greater than 0.

Claims

1. A crosslinkable composition based on organosilicon compounds comprising (A) organopolysiloxanes of the formula
(R.sup.7O).sub.3-aSiR.sup.3.sub.aO(SiR.sup.4.sub.2O).sub.nSiR.sup.3.sub.a(OR.sup.7).sub.3-a   (I), where R.sup.4 may be the same or different and are monovalent, optionally substituted hydrocarbon radicals, R.sup.7 may be the same or different and are monovalent, optionally substituted hydrocarbon radicals, R.sup.3 may be the same or different and are monovalent, optionally substituted hydrocarbon radicals, a may be the same or different and is 0 or 1 and n is an integer from 30 to 2000, and (B) siloxanes of the formula (II) ##STR00003## where R may be the same or different and are monovalent, optionally substituted hydrocarbon radicals, R.sup.1 may be the same or different and are monovalent hydrocarbon radicals having 2 to 16 carbon atoms, —CH.sub.2—NR.sup.6R.sup.5 radicals or —CH.sub.2NR.sup.11 radicals where R.sup.5 are hydrocarbon radicals having 1 to 12 carbon atoms, R.sup.6 is a hydrogen atom or radical R.sup.5, and R.sup.11 is a divalent hydrocarbon radical which may be interrupted by heteroatoms, R.sup.2 may be the same or different and are monovalent, optionally substituted hydrocarbon radicals, x may be the same or different and is 0 or an integer from 1 to 9 and z is 1 or 2, with the proviso that the sum of all x in formula (II) is greater than 0.

2. The composition as claimed in claim 1, characterized in that the radical R.sup.1 are aliphatic hydrocarbon radicals having 2 to 16 hydrocarbon atoms.

3. The composition as claimed in claim 1 or 2, characterized in that the radical R.sup.3 is a —CH.sub.2—NR.sup.6′R.sup.5′ radical or a —CH.sub.2NR.sup.11′ radical, where R.sup.5′ are hydrocarbon radicals having 1 to 12 carbon atoms, R.sup.6′ is a hydrogen atom or radical R.sup.5′, and R.sup.11′ are divalent hydrocarbon radicals which may be interrupted by heteroatoms.

4. The composition as claimed in one or more of claims 1 to 3, characterized in that said composition comprises component (B) in amounts of 1 to 20 parts by weight, based on 100 parts by weight component (A).

5. The composition as claimed in one or more of claims 1 to 4, characterized in that said composition comprises component (C) consisting of silanes of the formula
(R.sup.8O).sub.4-bSiR.sup.9.sub.b   (III) and/or partial hydrolyzates thereof, where b is 0, 1 or 2, R.sup.8 may be the same or different and are monovalent, optionally substituted hydrocarbon radicals and R.sup.9 are monovalent, optionally substituted hydrocarbon radicals.

6. The composition as claimed in one or more of claims 1 to 5, characterized in that it is a composition comprising (A) organopolysiloxanes of the formula (I), (B) siloxanes of the formula (II), optionally (C) silanes of the formula (III) and/or partial hydrolyzates thereof, optionally (D) curing accelerators, optionally (E) plasticizers, optionally (F) fillers and optionally (G) additives.

7. The composition as claimed in one or more of claims 1 to 6, characterized in that it is a composition comprising (A) organopolysiloxanes of the formula (I), (B) siloxanes of the formula (II), (C) silanes of the formula (III) and/or partial hydrolyzates thereof, (D) curing accelerators, (F) fillers and optionally (G) additives and is free from (E) plasticizers.

8. A process for producing the compositions as claimed in one or more of claims 1 to 7 by mixing the individual constituents.

9. A molding produced by crosslinking the compositions as claimed in one or more of claims 1 to 7 or produced as claimed in claim 8.

10. The molding as claimed in claim 9, characterized in that said molding has a stress at 100% elongation of preferably less than 0.4 MPa.

11. A siloxane of the formula (II), where R may be the same or different and are monovalent, optionally substituted hydrocarbon radicals, R.sup.1 are —CH.sub.2—NR.sup.6R.sup.5 radicals or —CH.sub.2NR.sup.11 radicals where R.sup.5 are hydrocarbon radicals having 1 to 12 carbon atoms, R.sup.6 is a hydrogen atom or radical R.sup.5, and R.sup.11 is a divalent hydrocarbon radical which may be interrupted by heteroatoms, R.sup.2 may be the same or different and are monovalent, optionally substituted hydrocarbon radicals, x may be the same or different and is 0 or an integer from 1 to 9 and z is 1 or 2, with the proviso that the sum of all x in formula (II) is greater than 0.

Description

Examples 1-9

[0091] The amounts of the oligomeric mixture B1 specified in Table 1 were added in each case to 250 g of the RTV1 base mix BM1 and mixed in in a planetary mixer of the Labmax type. The mixture thus obtained in each case was then filled into moisture-proof containers. 24 hours after the production of the mixtures, 2 mm thick plates were taken out of these mixtures and, after 7 days of curing at 23° C. and 50% relative humidity, dumbbell-shaped test specimens of type 2, in accordance with ISO 37, 6th edition 2017-11, were produced therefrom. The mechanical properties that were measured on these test specimens can be found in Table 1.

Comparative Example 1(C1)

[0092] 250 g of the RTV1 base mixture BM1 without further additives were filled in moisture-proof containers. 24 hours after the production of the base mix, 2 mm thick plates were taken out and, after 7 days of curing at 23° C. and 50% relative humidity, dumbbell-shaped test specimens of type 2, in accordance with ISO 37, 6th edition 2017-11, were produced therefrom. The mechanical properties that were measured on these test specimens can be found in Table 1.

Example 10

[0093] The experiment according to Example 1 was repeated with the modification that 5 g of the oligomeric mixture B2 were added instead of the oligomeric mixture B1. The mechanical properties that were measured on these test specimens can be found in Table 1.

Example 11

[0094] The experiment according to Example 1 was repeated with the modification that 5 g of the oligomeric mixture B3 are added instead of the oligomeric mixture B1. The mechanical properties that were measured on these test specimens can be found in Table 1.

TABLE-US-00001 TABLE 1 Tensile Elongation Stress at 100% Oligomeric strength at break elongation Example mixture [MPa] [%] [MPa] 1 B1  5.0 g 2.06 417 0.61 2 B1  7.5 g 1.80 420 0.55 3 B1 10.0 g 1.93 494 0.49 4 B1 12.5 g 1.57 496 0.42 5 B1 15.0 g 1.66 525 0.41 6 B1 17.5 g 1.48 548 0.37 7 B1 20.0 g 1.29 572 0.32 8 B1 22.5 g 1.02 601 0.27 9 B1 25.0 g 0.85 723 0.21 C1 0.0 1.90 355 0.68 10 B2  5.0 g 2.48 513 0.58 11 B3  5.0 g 2.28 451 0.62