DE1961555B2 - RESIN-LIKE POLYSILOXANE MOLDING COMPOUND OR COATING COMPOUND THAT CURES AT ROOM TEMPERATURE - Google Patents

Description

R ¹

to the remaining Si atoms in the resinous poly |

siloxane is 1: 3 to 1:20.

3. Molding or coating compound according to An40
Claim 1 or 2, characterized in that they
as a curing catalyst dialkyldiacyltin compounds, preferably dibutyltin dilaurate, in amounts of 0.1 to 5, preferably 0.5 to 3 weight - in which R ^{1 is} an alkyl or an aryl radical or contains percentages. 45 interpretation of the group OR ² and OR ^{a is} an alkoxy radical

4. Molding or coating composition according to one with 1 to 4 carbon atoms or the rest
or more of the preceding claims, tqq jj ι Q ^ e
characterized in that they are in a solution 24 »

medium, preferably an aromatic solution, in which R ^{3 is} an alkyl, preferably the methyl radical, medium, in particular benzene, toluene or xylene 50 and η has a value of 1 or 2, is free or mixtures thereof, is dissolved. of silanol groups and is known per se metal

Contains organic curing catalysts in amounts of 0.1 to 5 percent by weight.

The curing of the molding composition according to the invention

55 or coating compound probably happens in the

Way that in the presence of humidity and

under the action of the organometallic catalysts

The invention relates to ^{hydrolyzing the OR a} groups under the action of and then condensing water, including air humidity, in the event of room condensation.

temperature-curing resinous polysiloxane molding compound 60 As mentioned above, the radical R ¹ can be the coating compound. have meaning of an alkyl radical. Are preferred

Resin-like polysiloxanes (also silicone resins - the lower alkyl radicals, such as the methyl or named) usually consist of mono-, di-, tri- and ethyl radicals. However, higher alkyl tetrafunctional silicon units can also be used. Your condensate residue. In one example, a silicone resin is described for higher molecular weight compounds and ^{outputs, in which the radical R 1 has} the meaning of an octadehardening is brought about by the fact that it has a silanolcyclic radical. However, these residues already have a plasticizing effect on the resin groups with the elimination of water. This can condense for special. This requires the application of higher expressions to be desired. The remainder R ¹ can

OR ²

also have the meaning of an aryl radical, the phenyl radical being preferred,

The OR ⁸ radical can have the meaning of a lower alkoxy radical which can have up to 4 carbon atoms. Examples are the methoxy, Ätlioxy-, n-propoxy, ί-propoxy, n-butoxy or i-butoxy radical. The OR ⁸ radical can also mean an alkylene glycol monoether radical of the general formula

[OC ₁ H ₄ I ₁₁ OR "

to have. In this formula, η has a value of 1 or 2. R ^a is an alkyl radical, preferably the methyl radical.

The content of the silicone resin at the end of the formula

R ¹

be carried out according to the following reaction scheme;

■ SiOH + Cl- SiRKOR ⁸ ) «-> η SiOSiRKOR ¹ year

This reaction scheme is based on the principle of reacting corresponding siloxanols with chlorosilanes, which have at least two carbyloxy groups. The hydrogen halide released during the reaction can be intercepted by acid acceptors such as ammonia. The reaction becomes convenient carried out at elevated temperature.

Another, known manufacturing process is based on the implementation of corresponding siloxanols with tri- or tetraalkoxysilanes:

- Si - 0R ^a

OR ²

is variable within wide limits. From the task as position is evident to the person skilled in the art that one for crosslinking with curing There must be a minimum number of such groups. Those are particularly preferred Silicone resins containing these groups in a molar ratio of 1: 3 to 1:20, based on the remaining Si atoms of the resin contain.

In principle, all of the prior art (»Chemistry and Technologie der Silicones "by Walter Noil, Verlag Chemie GmbH, 1968, p. 340) known compounds be taken, but the dialkyldiacyltin compounds, preferably dibutyltin dilaurate, are preferred. These curing catalysts add 0.1 to the silicone resins at any point after their manufacture to 5 percent by weight, preferably in amounts of 0.5 to 3 percent by weight, added.

With exclusion of atmospheric moisture, the catalyst-containing molding compositions according to the invention are or coating compounds have a virtually unlimited shelf life. A particular advantage is that the molding compounds or coating compounds can be stored and used without solvents, provided they inherently have a viscosity that allows them to be processed. However, are the resins for a direct processing to high viscosity or is the use of solutions of synthetic resins from others Appropriate for reasons, the molding compositions or coating compositions in the form of the compounds customary solvents, preferably aromatic solvents, esters or ketones, are dissolved. Examples of such solvents are benzene, toluene, xylene, their mixtures, commercially available aromatic ones Distillates or solvents based on esters and ketones, such as. B. ethyl acetate, butyl acetate, ethyl glycol acetate or methyl ethyl ketone.

The silicone resins can be composed of various Si units. Examples of such units are CH ₃ Si0 _3/2 , (CHg) ₂ SiO, C _e H ₅ Si0 _3/2 , (C _e H ₅ ) ₂ SiO, (CHp) ₃ SiO, SiO _4/2 or (CH ₃ ) HSiO.

The preparation of the silicone resins, which is not claimed in the context of this invention, can, for. B.

R ¹

R ¹

= Si - OH + R ² O - Si - OR ² -> s SiO-Si-OR ²

20 OR ⁸

0R ^a

The invention, under the action of water, especially humidity, at room temperature hardening resinous polysiloxane molding compounds or coating compounds can be used anywhere can be used where silicone resins have previously been used. However, they are particularly beneficial there to be used where higher temperatures cannot be used. This is e.g. B. the case if the substrate to be coated with the silicone resin is temperature-sensitive or because of it Dimensioning is not readily suitable for the application of baking techniques. So suitable The molding compositions or coating compositions according to the invention z. B. for the coating of Luminescent tubes or screens, it being possible for the resins to be pigmented with phosphors. Another The purpose of use is the description of technical papers, e.g. B. of photocopy papers, which contain heat-sensitive pigments.

The subject matter of the invention is explained in more detail in the following examples. The ones in the The parts given in the examples are parts by weight.

example 1 Manufacture of the silicone resin

In a 500 ml three-necked flask provided with a reflux condenser, a stirrer, a dropping funnel and an inlet pipe, 225 g of a 25 ° / _o solution of a cohydrolyzate of methyltrichlorosilane and dimethyldichlorosilane with a content of OH groups of 4, 2 percent by weight and a molar ratio of CH ₃ : Si = 1.2: 1 in toluene. With stirring and simultaneous introduction of gaseous NH ₃ , 19 g of C _e H ₅ Si (OC ₂ H ₆ ) ₂ Cl are added ^{dropwise at 50 °} C. over the course of 15 minutes. The molar ratio of OH groups in the aforementioned cohydrolyzate and Cl in the silane is 1: 1. With continued stirring, NH _{8 is introduced} at 50 ^° C. for a further hour. Then the reaction mixture is slowly heated to 10O ⁰ C and stirred for 1 hour at this temperature. The mixture obtained is freed from the ammonium chloride formed by filtration.

After a temperature load of 200 "C. The molding composition erfiiidungsgemüße ₂ 4 hours Product 1 and 2 give the Cross Hatch

The solution obtained is treated with i ^u / ₀ dibutyl values Gt 0.

tin dilaurate, based on the solid content. Under example 4

With the exclusion of air humidity, no condensation occurs

sation, while the production of the silicone resin is painted on a glass plate
and exposed to the influence of humidity

Product after several hours a solid film 490.5 g of a 25 ° / _o by weight of a toluene solution

forms. Part of the solution is cohydrolyzed by distillation of 135 parts of methyltrichlorosilane,

completely freed from the solvent. This consists of 17.5 parts of dimethyldichlorosilane, 17.5 parts of Tnme-

any remaining ammonium chloride that falls is filtered off. The thylchlorosilane, 23 parts of methyldichlorosilane and

liquid, dibutyltin dilaurate containing 100 ° / ₀ sodium 17.5 parts of tetrachlorosilane containing

Resin remains with the exclusion of atmospheric moisture OH groups of 1.15 ° / ₀ are analogous to Example 1

liquid, but condenses when exposed to atmospheric moisture - with 20 g CeH ₆ Si (OCaH ₁ S) ₈ Cl corresponding to one

a solid product. »5 OH: Cl ratio of 1: 1 implemented.

^{B eJ sp! e l 2} molding compound according to the invention
Manufacture of the silicone resin

As described in the Example 1. Both the filtered solution and the by Lion gestures 324 g of a 25 ° / _o by weight toluene solution of such solvents freed liquid resin remain dichlorosilane after addition cohydrolyzate of methyltrichlorosilane and dimethyl- 1% dibutyl tin dilaurate to the exclusion of with a content of OH groups from humidity liquid. The molding compounds condense 2.6 percent by weight and a molar ratio of sieren, painted on glass plates, with the ingress of CH ₃ : Si = 1.2: 1 with 19.5 g of CH ₃ (OC ₂ H ₀ ) ₂ SiCl by ambient humidity fixed films,
sets, corresponding to an OH: Cl ratio of 1: 1. »5

Molding Composition According to the Invention Example 5

Both the filtered solution and that of the Lö- Manufacture of the silicone resin
Solvent-free liquid resin remains after addition

1% dibutyl tin dilaurate to the exclusion of air 30 240 g of a 25 ° / ₀ solution of a cohydrolyzate

moisture liquid. In the presence of atmospheric moisture, methyltrichlorosilane and dimethyldichlorosilane with

hardens the silicone resin. an OH group content of 2.6 percent by weight and a molar ratio of CH ₃ : Si = 1.2: 1

If 1 3 in toluene are analogous to Example 1 with 25 g

35 C ₁₈ H ₃₇ Si (OC ₂ H ₅ ) ₂ Cl corresponding to an OH: Cl relationship

Production of the silicone resin ratio of 1: 1 implemented. The solution of the

As described in the Example 1 to the resin a 25 ° / _o by weight toluene solution is liquid, the solvent-free product 324 g of a waxy.
Cohydrolysates of methyltrichlorosilane and dimethyldichlorosilane with an OH group content of 40 Molding composition according to the invention
2.6 weight percent and a molar ratio of

CH ₃ : Si = 1.2: 1 with 39 g of CH ₃ Si (OC ₂ H ₆ ) ₂ Cl created both solution and that from the solvent

In accordance with an OH: Cl ratio of 1: 2, the waxy resin that has been freed from the material also changes

sets (product 1). Addition of 1 ° / _? Dibutyltin dilaurate with the exclusion of

Using the same procedure, 153 g of a 45 humidity will not be. But they condense at 25 ° / _o strength toluene solution of a cohydrolyzate glass plates coated, on admission of Luftfeuchtigvon methyltrichlorosilane and dimethyldichlorosilane with ness to solid films with greasy handle,
an OH group content of 2.6 percent by weight and a molar ratio of CH ₃ : Si = 1.2: 1 B eisdie 1 6
with 28 g of C "H ₆ Si (OC ₂ H _{5) 2} Cl according to a 50 ^v
OH: Cl ratio of 1: 2 implemented (product 2). Manufacture of the silicone resin

The inventive molding composition _{in a} 500-ml three-necked flask is allowed to 200 g or coating composition _{of a} 25 ° / _o by weight toluene solution of a Cohydroly-Products 1 and 2 were mixed with 1 ° / ₀ dibutyltin 55 sates offset from methyltrichlorosilane and Dimethyldichlordilaurat and remain also in the presence of silane with a content of OH groups of 2.6 solvents with the exclusion of atmospheric moisture percent by weight and a molar ratio of CH ₃ : Si liquid. On exposure to moisture = 1.2: 1, they condense with 63.7 g of tetraethoxysilane and 1.1 g of titanium to form solid bodies. butoxide catalyst reapplied to deep-drawn metal sheets for 4 hours under reflux and rinsed by humidity. The solvent is then distilled off, and films which have condensed out show the values given in the following table, the excess tetraethoxysilane and the resulting table. which alcohol. 6.8 g of ethanol were formed

(theoretically 7.04 g ethanol).

65 Molding compound according to the invention

The freed from the solvent liquid resin remains ° / ₀ dibutyltin dilaurate after addition of 1 under

product Erichsen depression Cross-cut Pencil hardness 1
2 8.0 mm
9.9 mm GtI
GtO 5H
2H

7 8

Exclusion of humidity liquid. The molding compound CH ₃ : Si = 1.2: 1 is condensed analogously to Example 1 with 117.8 g but, painted on glass plates, with addition of CH ₃ Si (OC ₂ H ₄ OCH ₃ ) ₂ Cl corresponding to an OH: Cl occurs Humidity to solid films. Ratio of 1: 2 implemented.

Example 7 5 Molding composition according to the invention

_TT ,,, _o .,.,, Both the filtered solution and the solution from

Production of the silicone resin solvent-free liquid resin also remain after

200 g of a 25 ° / _o by weight toluene solution of a resin addition of 1% dibutyl tin dilaurate to the exclusion of

Cohydrolysates of methyltrichlorosilane and dimethyl from humidity liquid. But they condense

dichlorosilane with a content of OH groups of xo is painted on glass plates, in the presence of humidity

4.2 weight percent and a molar ratio of strength to solid films.

2372 V ^; 'i

Claims (2)

Temperatures. Silicone resins are therefore baked in in the patent claims: Rule. The condensation of the silanol groups can be 1. Under the action of water, including pointing silicone resins also cause that Humidity, Catalysts which cure at room temperature are added, Catalysts of this kind Resin-like polysiloxane molding compounds or -beschich- are organometallic compounds, such as, for example, sealing compound, characterized by butyltin dilaurate. The addition of curing catalyst the resinous polysiloxane end groups of the gates must be done immediately before processing, Structure as the mixtures only have a limited pot life _R1 ίο and already at room temperature within a short time I condense time (»Chemistry and Technology of I, Silicones «by Walter No 11, Verlag Chemie GmbH, - Si - OR ⁸ 1968, p. 357 ff.). Premature hardening can be counteracted by using the resins OR ^a 15 in relatively large amounts of solvents dissolves and / or adds very small amounts of catalyst. wherein R ¹ is an alkyl group or an aryl group, or both methods are measures anwemdungsdie meaning of the group OR ⁸ and has ^a 0R, a technically disadvantageous. In the first case, medium amounts of the residual solvent have to escape from the alkoxy radical with 1 to 4 carbon atoms or the applied resin solvent layer, with films of very small [OC ₂ H ₁ I) ₁ OR ³ layer thicknesses, which are also often porous are. Due to the small amounts of catalyst where R ^{3 is} an alkyl radical and η then also follows the curing of the films has a ratio of -1 or 2, free of silanol groups is moderately slow. and organometallic curing agents known per se. The invention is based on the object of space catalysts Curing in amounts of 0.1 to 5 weight temperature and despite the addition of a catalyst contains percent. excluding water, including air 2. Molding or coating compound after moisture, synthetic resins that can be stored for any length of time in Claim 1, characterized in that the molar form of one-component systems to obtain the Group 30 ratio is storage-stable even in the absence of solvents _{R 1} stay. 1 Surprisingly, this task can be accomplished by a I resinous polysiloxane in the invention - Si - OR ⁸ molding compound or coating compound are dissolved, I 35 which end groups of the structure 0R ^a