DE1803274C3 - Cure catalysis of RTV organopolysiloxanes - Google Patents

Description

Bis (acetoxybutylphenyltin) oxide,

Bis (acetoxydibutyltin) oxide,

Bis (dibutyl (dodecyloxy) tin) oxide,

Bis (dibutyl (hexyloxy) tin) oxide,

Di-tert-butylbromotin hydroxide,

Di-tert-butylchlorotin hydroxide,

Diphenylchlorotin hydroxide,

Bis (allylo? .Y) dibutyltin,

Bis (benzoxyloxy) dibutyltin,

Bis (benzyloxy) diethyltin,

Bis (1 -carboxyethoxy) diethyltin,

Diamyldibutoxy tin.

Diamyl dipropoxy tin,

Dibutoxydibutyltin,

Dihutyl bis (o-carbomethoxyphenoxy) tin,

Dibutylbis (dodecyloxy) tin,

Dibutylbis (octyloxy) tin,

Dibutyl diethoxy tin,

Diethoxydiphenyltin,

Diethyl bis (2-ethoxyhexyloxy) tin,

Dimethoxydiphenyltin,

Ethoxydiethyltin fluoride,

Butoxydiphenyltin oleate,

Dibutyl (2-carboxyethyl) tin,

Dibutyl methoxy tin acetate and

Dibutyl methoxy tin laurate.

The invention relates to organotin compounds. As mentioned above, these can be catalysts Formula gates slowly vulcanizing one-component systems of the formula

in which X is hydrogen or the group

R.

-Sn '

l \

Y 'R'

20th

where Y and Y 'are hydroxyl, halogen, OOCR "or OR groups and R, R' and R" are hydrocarbon radicals represent, as a curing catalyst in compositions curable at room temperature based on terminal hydroxyl groups Organopolysiloxanes and crosslinking agents or organopolysiloxanes with by ambient moisture hydrolyzable residues.

2. Embodiment according to claim 1, characterized in that R and R 'are alkyl radicals.

3. Alis guide form according to claim 1, characterized in that X is the group

-Sn

35

Y 'R'

4. Embodiment according to claim 3, characterized in that Y and Y are 'OOCR "radicals.

5. Embodiment according to claim 3, characterized in that X is hydrogen and Y is a Is halogen.

40

45

Sn-OX

/ I

R 'Y

in which R and R 'are hydrocarbon groups, X is hydrogen or the group

55 [Z] ₁ ^ ₁ -SiO

SiO

R ^b

F-

Si— [Z] _11. ,

-Sn

Y 'R'
, Y and Y 'is hydroxy, halo, OOCR "- or incorporated, are wherein R" and R ^b, which may be identical or different, monovalent hydrocarbon radicals, halogenated monovalent hydrocarbon radicals or cyanoalkyl radicals, Z is a hydrolyzable by atmospheric moisture residual , η is an integer from 2 to 4 and χ is an integer from 1 to 20000.

In the above formula, R * and R ^{b are} organic radicals, namely alkyl radicals with 1 to 18 carbon

lenstofTatoraen: such as methyl, ethyl, propyl-butyl, hexyl, octyl, decyl, dodecyl, tetradecyl or octadecyl radicals, aryl radicals, such as. B. phenyl, diphenyl or napbtbyl radicals, alkaryl radicals. like ζ. Β Toluyl-, XyIyI- or Äthylphenylreste, aralkylreste s such. B. benzyl or phenylethyl radicals, haloaryl radicals. such as B. chlorophenyl, tetrachlorophenyl or difluorophenyl, alkenyl such. B. vinyl or allyl radicals. Examples of the hydrolyzable groups represented by Z are monoacyl radicals of to carboxylic acids, such as acetoxy, propionyloxy, valeryoxy, caproyloxy, myristoyloxy or stearoyloxy groups, carbonoxy groups with 1 to 10 carbon atoms, such as methoxy, ethoxy, butoxy , Heptoxy, octoxy, decoxy or phenoxy groups] aminooxy groups, such as e.g. B. dimethylaminooxy, diethylaminooxy, dipropylaminooxy, dibutylamino-OXV-. Dioctylaminooxy, diphenylaminooxy, ethyl methyluminooxy or methylphenylaminooxy groups, oximo radicals, such as r. B. acetophenoximo-, acetoneoximo-, benzophenoximo-, 2-bulanoximo-. Diisopropyl ketone oximo. Chlorocyclohexane oximo or alpha-bromoacetophenoximo groups.

Organolpolysiloxanes containing acyloxy groups may have been prepared by using hydroxy-terminated organopolysiloxanes with acyloxysilanes of the formula RV _n Si (Ac) _n , where R ^a and η are the same as those shown above and Ac is an acyloxy group, in a ratio of at least one mole of acyloxysi. ^ n per mole of silicon bonded ^ _{0 that} hydroxyl group at a temperature of about 20 to 100 C have been reacted. If desired, higher or lower temperatures can be used, although a reaction carried out below about 200 ° C. is preferred.

If the hydrolyzable groups on the organopolysiloxanes are aldo or ketooximo groups, then they can be made by reacting liquid hydroxyl-terminated organopolysiloxanes of suitable viscosity with that obtained from the implementation of an organotrihalosilane and an aldo or keto oxime Manufacture product.

These organopolysiloxanes containing hydrolyzable groups can thereby be vulcanized. that they are simply exposed to the humidity of the air: vulcanization can also take place at room temperature be carried out in the presence of additional steam. When the mixture of moisture is exposed, cross-linking of the material occurs. depending on the type of hydrolyzable group and the type of tin catalyst used takes a few minutes to an hour.

In the two-component system, the catalysts are incorporated into a composition which an organopolysiloxane with functional groups. most of which to the terminal silicon atoms are bound, and contains a crosslinking agent. The organopolysiloxane, preferably one hydroxyl-terminated organopolysiloxane, can by the formula

R *

As mentioned above, crosslinking agents such as, for example, polyalkoxysilanes of the formula

HO-

SiO

TT

60

fts

be shown, where R ", R ^b and χ have the meaning given above.

or polyalkoxysiloxanes, in which the Silicmraatome connected via Si-O-Si groups and the rest Valences of the Siüciuraatonjs through R "'O and / or R '"are saturated, added to the mixture of an organopolysiloxane and the tin catalyst.

In the above formula, the groups represented by R '"are monovalent hydrocarbon radicals with fewer than 8 hydrocarbons, choose monovalent groups represented by R "" Hydrocarbon radicals or balanced hydrocarbon radicals with fewer than 8 carbon atoms and ζ has a value of 3 to 4. Examples of the 1 hydrocarbon radical represented by R '" are methyl. Ethyl, propyl, butyl, hexyl, octyl, phenyl. Vinyl, allyl, ethylallyl or butadienyl radicals. The residues represented by R "" may be the same as those represented by R '" Be radicals and the corresponding halogenated radicals, such as. B. chloromethyl-. 2-bromo-4,6-diiodophenyl-. 1,2-difluorovinyl-, ß / l-dinuorcyclopentyl-, I-bromocyclopentene-I ^ -tI- or 6-chlorohxyl radicals. to the polyalkoxysilanes used here include Monoorganotrihydrocarbonoxysilane.Tetrahydrocarbonoxysilane. z. B. orthosilicates or partial hydrolysates of such silanes. The polyalkoxy compounds. such as B. ethyl orthosilicate or partially hydrolyzed ethyl silicate, such as ethyl silicate "40". that consisting mainly of decaethyl tetrasilicate are typical of these compounds. Examples of others More effective alkyl silicates are ethyltrimethoxysilane, methylbutoxydiäthoxysilan. Propyltripropoxysilane. Methyltriäthoxysilan, Äthyltriäthoxysilan, Äthylorthosilikat or n-Butylorthoäüikat. examples for Alkyl polysilicates are ethyl polysilicate, isopropyl polysilicate or butyl polysilicate. Dimethyltetraäthoxydi-.iiloxane or Trimethylpentabutoxytrisiloxan.

The polyalkoxysilanes and polyalkoxysiloxanes used can either be used alone or together and should, based on the weight of the Organnpoiysiloxane, in a ratio of about 0.5 to IU weight percent, preferably from about 1 to 5 weight percent. When the total weight the polyalkoxysilanes or polyalkoxysiloxanes, based on the weight of the organopolysiloxane, is below about 0.5%, there is only very little crosslinking. Is the total weight of the Polyalkoxysilanes or polyalkoxysiloxanes, however, more than about 20 percent by weight, based on the Weight of the organopolysiloxane, the vulcanization time cannot be shortened significantly. However If there is a large excess of crosslinking agent, there is a complete reaction with all those bonded to silicon Hydroxyl groups are guaranteed and, in addition, any moisture that may be present is bound.

The vulcanization of these organopolysiloxane compositions is achieved in that the hydroxyl-terminated polysiloxanes in the presence of Organotin catalysts used according to the invention with the polyalkoxysilanes or polyalkoxysiloxanes be mixed. These catalysts can be dispersed in an inert solvent and then added to the polysiloxane, or on

A filler is applied and then ground with the Qrganopolysiloxan. Examples of hydrocarbon solvents are benzene, toluene or xylene, halogenated hydrocarbons, such as. B. Percbjoroethylene or chlorobenzene, organic ethers, such as, for example, dietary ether or dibutyl ether. or liquid, hydroxyl-free polysiloxanes suitable. Solvents that are so fluid that they are already at evaporating at a very low temperature are preferred.

The organopolysiloxanes can be processed in the manner customary in the manufacture of conventional siloxane elastomers. However, if the materials are stored before use, the organotin catalyst or the verifier, such as B. the PolyaJkoxysilan or the Polyilkoxysiloxan, are stored separately. In other words: the hydroxyl-terminated polysiloxanes, the filler material and the crosslinker can be processed together, and the catalyst is added shortly before use. In another method, the polysiloxane, filler and catalyst are processed together and the crosslinker is added shortly before use. If an inert filler is used, it can be added to either the hydroxyl-terminated organopolysiloxane or the crosslinker before the catalyst is added or immediately after the reactants have been mixed together.

Immediately after the components, i. H. the organopolysiloxane, the catalyst, the crosslinker and optionally If the filler has been mixed, the vulcanization process of the mixture starts spontaneously Room temperature.

The tin compounds used in this vulcanization system are effective even in small amounts, for example from about 0.05 to 2.0 parts by weight, preferably from about 0.1 to 1.0 part by weight per 100 parts by weight of the mixture. Optionally, a mixture of two or more of the aforementioned organotin compounds can be used as catalysts. As mentioned above, these tin compounds can be added to the organopolysiloxane or, if desired, in a carrier, such as. B. incorporated a liquid or a comminuted solid or both liquid and solid components are added. In general, the carrier is inert: however, an active carrier can also be used.

The amount of catalyst that is added to the base mix depends on the particular one Purpose. in particular how long the mixture should be processable. For example, is the processing time for sealing work is around 1 to 2 hours. Hence, in this case, becomes the catalyst added in an amount that does not lead to a substantial hardening of the until after this time Silicone compound leads. The mixture usually sticks within 2 to 4 hours after the sealing process no longer; it is largely vulcanized after 24 hours and completely vulcanized after about 7 days vulcanized. These times may vary somewhat with changes in humidity and temperature. For example faster vulcanization is achieved at higher temperatures and higher humidity.

Although not essential, fillers are sometimes incorporated into these mixtures in order to impart desirable properties to them. As fillers are a B. silicas obtained in the vapor phase, precipitated silicas with a large surface area, silicic acid aerogels, and coarser silicas, such as. B. kieselguhr or ground quartz suitable. Other fillers that can be used are metal oxides such as e.g. B. Titanoxyd, Femoxyd or Zmkoxyd, and fibrous fillers such. B. asbestos or fiberglass. Hs can also contain other additives, such as B. antioxidants or ultraviolet absorbers are incorporated into these mixtures.

Although the particle size of the fillers and additives is not critical, particles about 0.14 to 2 microns in diameter are preferred. Larger diameter particles can also be used; however, they are more difficult to incorporate into the mixture.

If the organotin catalysts are used according to the invention, the time to achieve a non-stick surface, which is an acceptable measure for vulcanization times, can be shortened from several hours to a few minutes, depending on the type and concentration of the catalyst.

However, these catalysts not only reduce the time taken to achieve a non-sticky one. surface shortened, but also accelerated the vulcanization of the entire · ,, treated part. With help of the catalyst described and used in the correct concentration can thus be a complete Vulcanization, which usually takes 3 to 7 days without a catalyst, in just about 36 hours achieve. The use of these catalysts in such one- and two-component systems as they are described above is completely new to the vulcanization technique.

The compositions described here have a wide range of uses. For example, you can as a means for tooth prints, as sealing joints for adjacent road sections, as insulating materials for electrical elements, as sealing materials or as adhesives.

In the following examples, various embodiments of this invention are explained in more detail, all parts being expressed as parts by weight unless otherwise stated.

Example! 1

About 100 parts of a liquid hydroxyl terminated dimethylpolysiloxane having a viscosity of About 200OcS about 5 parts of ethyl orthosilicate and about 77 parts of iron oxide are added. The mixture is heated to about 275 ° C. with stirring and then cooled to room temperature.

About 100 parts of this mixture is added to 0.1 part of bis (dibutyltin laurate) oxide and then mixed on a three-roll mill for about j minutes. The mixture is then poured into a mold and vulcanized at room temperature. After about 27 minutes the mixture is non-sticky and fully vulcanized after about 24 hours.

Example 2

In the method of Example 1, bis (dibutyltin laurate) oxide is replaced by about 0.1 part of a K.

tors of the formula

[(C ₄ H _{9 I 2} SnCl] ₂ O

replaced. The mixture is tack-free after about 35 minutes.

Example 3

In the procedure of Example 1, bis (dibutyltin laurate) oxide is passed through about 0.1 part of a catalyst the formula

(C ₄ Hg) ₂ Sn (OH) CI

replaced. The mixture is tack-free after 24 minutes.
Example 4

In the procedure of Example 1, bis (dibutyltin laurate) oxide is replaced by about 0.1 part of bis (diamylchlorotin) oxide replaced. The mixture is tack-free after 70 minutes.

Example

In the procedure of Example 1, bis (dibutyltin laurate) oxide is used Replaced by about 0.1 part of bis (diphenyltin laurate oxide. After about 25 minutes that is Mixture non-sticky.

Example 6

In the procedure of Example 1, bis (dibutyltin laurate) oxide is replaced by about 0.15 parts of bis (tribenzyltin) oxide replaced. The mixture is tack-free after about 20 minutes.

Example 7

About 100 parts of a hydroxyl terminated dimethylpolysiloxane having a viscosity of about 250 ° C at 25 ° C are about 5 parts of a polyvinyltriethoxysilane with a viscosity of about 200OcS at 25 ° C and about 0.3 parts of a tin compound the formula

[(C ₄ H _{9 I 2} SnCl] ₂ O

admitted. The mixture is then transferred to a mold and vulcanized at room temperature. After about 15 minutes the mixture is non-sticky and after about 24 hours becomes a tough elastomer vulcanized.

Example 8

In the procedure of Example 7, methyltriacetoxysilane is substituted for polyvinyltriethoxysilane. After about 10 minutes the mixture is no longer sticky.

Example 9

About 100 parts of a liquid hydroxyl terminated dimethylpolysiloxane having a viscosity of About 150 oCs about 5 parts of Ethylorthosüikat and about 77 parts of iron oxide are added. The mixture is heated to 275 ° C. with stirring and then cooled to room temperature.

Be about 100 parts of this mixture at a time Catalysts added in various proportions, the mixtures about 3 minutes in one Blended three-roller mill. The mixture is then poured into a mold and vulcanized at room temperature.

The following table shows the vulcanization rates of the tin catalysts used according to the invention with the vulcanization rates of known catalysts compared. The table also shows the influence of the concentration on the vulcanization rates of the corresponding catalysts.

Vulcanization rates as a function of the concentration

Vulcanizing agents Concentration of vulcanizing agent

0.05

0.10 0.30

0.50

0.75

1.00

Time for bis (dimethyltin oleate) oxide
(Hours.)

Time for bis (dibutyltin laurate) oxide
(Hours.)....

Time for tHbutyMhalic acid (SfA)

Time for dibutyltin butoxychloride (hours)

1.0

10.1
4.7
8.6

0.5

1.0 3.0 2.9 0.2

0.5
2.6

2.3

0.2

0.4
1.8
2.1

0.2

0.3
1.4
1.7

0.3

1.1
1.5

If the above examples with other hydroxyl-terminated organopolysiloxanes in the presence are carried out by other catalysts used according to the invention, mixtures obtained in the have essentially the same vulcanization rates.

Claims (1)

1 8Q3 claims: 1. Use of an organotin vat formula Sn-OX / I R 'Y 10 OR groups and R "is a KoblenwasserstofT group, as hardening catalysts for the use of compositions of hydroxyl groups containing Qrganopolysfloxwen, which cure at room temperature in conjunction with crosslinking agents, or IUr compositions of organopolysiloxanes with residues hydrolyzable by ambient moisture.
Up to now, organopolysiloxanes have been vulcanized using organon catalysts such as dibutyl oxy-butyl chloride or dibutyl tin dilaurate. However, it has been found that the desired vulcanization rate could not be achieved with these catalysts. Therefore, inert one- and two-component vulcanization systems were unsuitable for some practical applications because of their low vulcanization rate. Obviously, there is a need for organopolysiloxane compositions which can be quickly vulcanized and which are particularly suitable as a hand-held product. Examples of compounds encompassed by the above formula are: