DE3411691A1 - METHOD FOR PRODUCING A SINGLE-COMPONENT SILICONE RUBBER MATERIAL, VULCANIZING AT ROOM TEMPERATURE - Google Patents

Description

Process for producing a one-component, at room temperature vulcanizing silicone rubber compound

The present invention relates to alkoxy-functional one-component, Room temperature vulcanizable silicone rubber compositions and more particularly, the invention relates to Alkoxy-functional one-component silicone rubber compounds that can be vulcanized at room temperature (hereinafter abbreviated to "RTV"), in which a curing accelerator is formed in situ.

One-component RTV silicone rubber compounds have been known for a long time. The first such masses were acyloxy-functional, d. H. the crosslinking agent was acyloxy functional. Such a mass could be in an essentially anhydrous state in a single Container to be packed. When it was desired to harden the mass, the seal on the package was broken. After exposure to atmospheric moisture, the mass cured into a silicone elastomer. Later were Alkoxy-functional one-component RTV silicone rubber compounds developed, d. H. those where the crosslinking agent was an alkoxy functional silane such as methyltrimethoxysilane. A An example of such a mass, which has also gained economic importance, is described in US Pat. No. 4,100,129. One such composition comprises a silanol-terminated diorganopolysiloxane polymer, a trialkoxysilane crosslinking agent, a titanium chelate catalyst as a condensation catalyst, a Filler and various other additives.

Although the bulk of the aforementioned US PS was marketable and had a shelf life of a year or more, and one economical had a useful curing rate, there were problems with these compositions. In some production batches of such masses the storage stability was found to be impaired, so

that mass changes dramatically after a month or two of storage deteriorated. In fact, it has been found that in most cases the storage stability of such compositions was impaired even after a storage period of two weeks. It was also found that some production batches such compositions had cure rates that were economically unacceptable. There were different ones Improvements made to the above measures and the stated difficulties alleviated to some extent, yet they have not been completely eliminated.

An improved commercial one part alkoxy functional RTV silicone rubber compound is described in EP-A-69 256. It is then assumed that unbound hydroxyl groups in. the RTV mass the impairment of the alkoxy groups on the terminal silicon atoms of the diorganopolysiloxane base polymer cause. It is further believed that such degradation of the alkoxy groups leads to progressive deterioration the curing rate and the storage stability of the RTV mass during storage.

Correspondingly, there is an improved alkoxy functional in EP-A-69 256 One-component RTV silicone rubber compound proposed which has an improved shelf life and curing speed by having certain silanes in the bulk with certain functional groups that clean the mass. Such silane cleaners react with the unbound ones Hydroxy groups in the RTV compound, bind them and prevent them from ^ the terminal alkoxy groups of the diorganopolysiloxane base polymer to affect. This increases the shelf life and the rate of hardening of the mass as well retained after prolonged storage. The shelf life of an acceptable commercial RTV silicone rubber compound must be such be that even after storage times of 6 to 12 months after production, the mass has a tack-free time of 120 Minutes or less. A more preferred compound is an alkoxy-functional one-part RTV silicone rubber compound which after one year of water-free storage in a container

or more a tack-free time of 60 minutes or less Has. Such compositions were developed as described in the above European patent publication. After this EP-A can contain the functional group in the silane that is unbound Hydroxy groups eliminated from the mass / be an amino group. In this EP-A it is further pointed out that if necessary, a hardening accelerator can be present which can be selected from amines and guanidines.

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In an older US with the serial no. 462 949 is the use certain alkoxy-functional, amine-functional siloxane cleaner or described by siloxanes, which crosslink at the same time as well as the bulk of undesired hydroxyl groups clean for alkoxy-functional one-component RTV silicone rubber compounds, which are similar to those described in EP-A-69256.

In EP-A-69 256 it is stated that the curing accelerator at a concentration of from 0.1 to 5 and preferably from 0.1 to 1 part and more preferably from 0.3 to 1 part 100 parts of the silanol-terminated diorganopolysiloxane polymer may be present. It is further noted that with such concentrations of the curing accelerator the mass has a tack-free time of less than 60 minutes after the uncured mass of a has subjected to accelerated aging. It is also stated in this EP-A that the silane, which is the mass of unbound Cleans hydroxyl groups and that can possibly be crosslinker at the same time, via the amount required to react with the end groups of the Diorganopolysiloxane base polymer containing silanol end groups is required, used in an excess of up to 3% can be. According to the EP-A mentioned, up to 0.5 part of the simultaneously crosslinking and cleaning silane is desirable to react with the end groups that a maximum of additional 3 wt .-% of this silane is added for cleaning purposes and that generally 0.1 to 5 parts, and more preferably 0.3 to 1 part, of an amine curing accelerator

to 100 parts by weight of the silanol terminated diorganopolysiloxane base polymer can be added.

It has been found in the present invention, surprisingly, that instead of adding one separately at the same time cleaning agent and the separate addition of a curing accelerator only an integrated crosslinker and has to add cleaner that is amine-functional to release a primary or secondary amine in sufficient quantity, mn to act as a curing accelerator.

It is an object of the present invention to provide a method for forming an in-situ curing accelerator in one Alkoxy-functional, one-component RTV silicone rubber compound to accomplish.

It is another object of the present invention to provide a method for making an amine-functional cure accelerator to create in place by having an integrated Amine-functional crosslinker and cleaner with a diorganopolysilixane polymer containing silanol end groups.

It is yet another object of the present invention to provide a method of making an amine functional cure accelerator in-situ in an alkoxy functional one part RTV silicone rubber composition create by having an integrated crosslinker / cleaner with primary and secondary functional amine groups with a diorganopolysiloxane polymer containing silanol end groups.

Another object of the present invention is to provide a method for making an alkoxy functional One-component RTV silicone rubber mass by putting in place and Place creates an amine-functional cure accelerator that results in an uncured mass that even after storage periods one year or more has a tack-free time of 60 minutes or less.

These and other objects of the present invention are achieved by the following invention.

According to the invention, a method for producing a one-component / Essentially acid-free silicone rubber compound created with a hardening accelerator produced in-situ immediately after the following ingredients have been mixed together:

(A) 100 parts by weight of a polydiorganosiloxane containing silanol end groups, which consists essentially of chemically linked units of the following formula

SiO -

(B) at least 5 parts of a silane for removing functional hydroxyl groups of the formula

(R ² ) _b

Si (X) ₃ '(C) 0-10 parts of a crosslinking silane of the formula

(R ² ) _b

(2) ^(Rio) (4-b) ^Si '

(D) an effective amount of a condensation catalyst, where R is selected from optionally substituted monovalent ones Hydrocarbon radicals with 1 to 13 carbon atoms, R an aliphatic organic radical with 1 to 8 carbon atoms is selected from the group consisting of alkyl, alkyl ether, alkyl ester, alkyl ketone and alkyl cyan radicals or aralkyl radicals with 7 to 13 carbon atoms,

3A 11691

R is an optionally substituted monovalent hydrocarbon radical with 1 to 13 carbon atoms, X is a hydrolyzable amino group, a has the value 1 or 3,
b has the value 0 or 1 and
the sum of a + b has the value 1 or 3.

The compound of formula (1) is an integrated crosslinker / cleaner , where X is a primary or secondary amine, and more preferably a secondary amine. After being released from the silane of the formula (1), the secondary amines react with the diorganopolysiloxane polymer having terminal silicon groups, form end groups on it, and also act as end-connecting catalysts and as curing accelerators. The released primary amines also act in this way.

Optionally, the excess crosslinking agent of formula (2) is added to the composition in order to terminate the ends of the silanol end groups having diorganopolysiloxane base polymer as far as possible with terminal alkoxy groups.

The integrated crosslinker / cleaner, be it a silane or siloxane, when reacting with the silanol groups of the diorganopolysiloxane polymer releases primary or secondary amines, which act as catalysts connecting the polymer ends in order to connect the ends of the silanol-terminated diorganopolysiloxane base polymer with the integrated crosslinker / cleaner zn catalyze and they also act as the curing accelerator to the tack-free time keeping the mass is preferably below 30 minutes after the mass for 1 year or longer has been stored. The preferred crosslinking agent is. Methyltrimethoxysilane and the preferred silane for bulk cleaning of hydroxyl groups is methyldimethoxy (di-N-hexylamino) silane.

So that the mass becomes an elastomer with for RTV silicone rubber masses usual properties, it is necessary that

the mass contains a condensation catalyst, which is preferably is a tin catalyst, such as. B. dibutyltin dilaurate and dibutyltin diacetate.

To 100 parts of the silanol terminated diorganopolysiloxane polymer there must be at least about 4 parts of the integrated crosslinker / cleaner to be a commercial To yield product, d. H. one that has a shelf life of about 6 to about 12 months, whereupon the tack-free time is 120 minutes or less. the preferred shelf life of an alkoxy-functional one-component RTV composition is a year or more and after that the mass should have a tack-free time of 60 minutes or have less. To obtain such storage stability, it is necessary that about 5 to 7 parts of the integrated Crosslinker / cleaner per 100 parts of the silanol terminated diorganopolysiloxane base polymer are present. While more than 7 parts of this integral component can be used, this will not produce useful results. The minimum amount of 4 parts was determined with the integrated crosslinker of Example I. This amount can therefore increase change to some extent with other types of amine-functional integrated crosslinkers / cleaners. This is why the minimum amount in the present description and in the claims with at least about 4 parts of the integrated crosslinker / Cleaner specified. Di-N-hexylamine is a secondary amine that is one of the more effective and preferred cure accelerators. This di-N-hexylamine, which according to Example I. is released in-situ as a hardening accelerator is a more effective curing accelerator than a primary amine. The results of Example I therefore indicate the minimum amount integrated crosslinker / cleaner, which is required to produce an alkoxy-functional RTV silicone rubber compound, which forms a hardening accelerator in-situ, which forms a mass with the correct shelf life and tack-free Time yields. Other released amines from the integrated crosslinkers / cleaners may be slightly more effective

and therefore the stated amount of about at least 4 parts indicates the minimum amount of integrated crosslinker / cleaner required in the composition to form an in-situ cure accelerator which will cure the composition at a suitable rate. This effect is not cumulative f since a minimum of about 4 parts of the integrated verifier / cleaner was not to be expected due to the use of the individual additives in the compound according to the above EP-A »According to this EP-A, the hardening accelerator is a separate compound, which is not formed in-situ, but is added to the mass during manufacture. On page 10 of the EP-A mentioned, it is stated that up to a 3% excess of the unbound hydroxyl-removing compound (cleaner) can be used in the mass.

In Example I of the present application, at least about 4 parts of the integrated crosslinker / cleaner were used per 100 parts of the diorganopolysiloxane polymer containing silanol end groups in order to obtain a commercially usable composition of the diorganopolysiloxane polymer containing silanol end groups to implement completely ο This is the theoretical value. Such an amount of integrated crosslinker / cleaner releases about 0.12 part of di-N-hexylamine as a hardening accelerator. If, according to the above-mentioned EP-A-69 256, the curing accelerator is added as a separate component and the integrated crosslinker / cleaner is added as a separate component to the compound, then a maximum of 3.5 parts of the integrated crosslinker / cleaner should be present in the compound . As the results of Example 1 show, it was necessary to have at least about 4 parts of the integrated crosslinker / cleaner in the composition in order to obtain a commercially viable RTV composition, that is, one that has a commercially acceptable shelf life and tack free time .

-9 ■

Ί3-

It follows from the foregoing, therefore, that the effect of the insitu Curing accelerator formed is not cumulative, as one would expect from the EP-A, but that this effect must be determined experimentally. Neither in the above EP-A nor in any of the other publications is the

situ-ßildung a curing accelerator and the composition of the present application. In all of these documents, the curing accelerator is a separate one Compound and a separate component that during mixing is added to the mass. One of the advantages and the fundamental advantage of the present composition is that it is easier to produce continuously, since only one is added instead of two separate components must be what the preparation of the mass by continuous mixing of the ingredients in a volatilization avoiding Extruder, as described in US application serial no. 437,895. This is true, though of that integrated crosslinker / cleaner is used more in bulk than one would normally use if one had a separate Curing accelerator added.

The compound of formula (1) is described in EP-A-69 256. However, this connection is different from this EP-A not just an integrated crosslinker / cleaner but one in which a single alkoxy group can be bonded to the silicon atom. It is therefore possible with such a built-in Crosslinkers / cleaners to produce masses in which the diorganopolysiloxane base polymer have only a single alkoxy group on the terminal silicon atom and one or two amine groups at the terminal silicon atom of the polymer chain. Such masses are within the scope of the present invention and they cure according to the disclosure of the present application. The preparation of such base polymer is also in the US patent application Serial No. 449 105. The compounds of formula (1) are more complete in the latter application as described in the above EP-A, according to which the integrated crosslinker / cleaner have at least two alkoxy groups

got to. Regardless of which of the two integrated Vernet - '$ er / cleaner is used, one obtains an end group-containing polymer in which the terminal silicon atoms are one or two or have three alkoxy groups which are in accordance with of the present disclosure form a curing accelerator in situ and have the consequence that the mass the desired Has shelf life and cure rate.

While the integrated crosslinkers / cleaners of the formula (1) end groups on the diorganopolysiloxane polymers containing silanol end groups, the released amines, which either may be primary or secondary amines, also as the end-connected catalysts, as disclosed in the above EP-A. Additional terminating catalysts can be employed as described in U.S. Patent Application Serial No. 427,930 disclosed.

The crosslinking silane of the formula (2) can optionally be used as an additional Crosslinkers in the bulk can be used to ensure that the maximum degree of chain termination of the silanol end groups containing diorganopolysiloxane polymers takes place and to su a high crosslinking density in the to be produced Lead elastomer.

Alternatively to or in combination with or instead of the silane as an integrated crosslinking agent / cleaner of the formula (1) an integrated crosslinker / cleaner of formula (3) can also be used

R ²

jy

f ⁱ⁰ 4-

A.
w

1 2
in which R and R have the meanings given below and A is a simple amine radical of the formula

JO

NO ¹¹

M.

IS-

wherein R ¹⁰ and R ^{11 are} individually selected from hydrogen and monovalent hydrocarbon radicals having 1 to 8 carbon atoms,

χ varies in the range from 0.05 to 2.50, y varies in the range from 0.00 to 2.50, w varies in the range from 0.05 to 1.5 and the sum of x + y + w has a value in the range from 2.10 to 3.00.

The compounds of the formula (3) are different from the compounds of formula (1) in that they are siloxanes, but they are nonetheless integrated crosslinkers / cleaners, such compounds have at least one alkoxy group and they have 2 to 20 silicon atoms. The functional amino group in such Siloxane of formula (3) is either a simple primary or secondary amine.

A more preferred amine-functional siloxane than an integrated one Crosslinker / cleaner is one of the following formulas

R ²

(R ¹ 0) _m kiO,

^A o

1 2
wherein R and R have the above meanings and A is a simple amine radical of the formula

R ¹⁰

wherein R and R are individually selected from hydrogen and monovalent hydrocarbon radicals with 1 to 8 carbon atoms,

m varies in the range from 0.15 to 2.50, η varies in the range from 0.1 to 1.9, ο varies in the range from 0.05 to 2.00 and the sum m + n + o has a value in the range from 2.10 to 3.00.

The compounds of the formula (4) are preferred integrated crosslinkers / cleaners within the framework of the formula (3), which have at least three alkoxy groups in the polymer part. These connections too can contain 2 to 20 silicon atoms in the polymer chain. With regard to the functional amino groups, the compounds must of formula (4) contain at least the same amount, d. there is an amino group in the polymer part, but they can maximally contain more amino groups in the polymer part than is possible with the compound of formula (3). The connections of the Formula (4) are therefore more preferred integrated crosslinkers / cleaners. For more information on making the connections of formulas (3) and (4) and their use in the production of alkoxy-functional one-component RTV silicone rubber compositions Reference is made to U.S. Patent Application Serial No. 462,949. The same connections that are in the aforementioned patent application are also contained in the present patent application with the additional Purpose the aforementioned quantities of integrated crosslinker / cleaner to be introduced into the mass so that a hardening accelerator is formed in the mass in situ. However, it is related to indicate with such compounds, especially those of high molecular weight and small number of amine groups, of which considerably larger amounts are introduced into the compound as integrated crosslinkers / cleaners must, as the minimum amount of about 4 parts, as specified for the simpler amines of formula (1).

The compounds of formulas (1), (3) and (4) can be used in the above EP-A-69 256, U.S. Patent Application Serial No. 449,105, and U.S. Patent Application Serial No. 462,949 will. Their use as an integrated crosslinker / cleaner is explained in detail in the registrations mentioned. It is only necessary that these ingredients are mixed into the mass in the aforementioned amounts so that they are not only integrated Crosslinkers / cleaners, but also act as mere cleaning compounds to keep primary and / or secondary in place To form hardening accelerators, which increase the hardening rate of the mass.

The silanol-terminated diorganopolysiloxane polymer preferably has the formula

R.
(5)

HO-

SiO.

wherein R is individually selected from monovalent, optionally substituted Hydrocarbon radicals with 1 to 13 carbon atoms and the radicals for R are preferably methyl or a mixture of a major amount of methyl and a minor amount of phenyl, Cyanoethyl, trifluoropropyl, vinyl and mixtures thereof are η in formula (5) is an integer with a value from about 50 to about 2500. Preferably this polymer has a viscosity in the range of 100 to about 400,000 centipoise, and more preferably it has a viscosity in the range of about 1,000 to about 250,000 centipoise measured at about 2! rated η in formula (5) from 500 to 2000.

250,000 centipoise, measured at about 25 C. Preferably va-

Examples of radicals which can stand for R in formulas (1), (2) and (5) are optionally halogen-substituted aryl radicals, such as Phenyl, tolyl, chlorophenyl, naphthyl; aliphatic and cycloaliphatic Radicals such as cyclohexyl, cyclobutyl; Alkyl and alkenyl radicals, such as methyl, ethyl, propyl, chloropropyl, vinyl, allyl, Trifluoropropyl and cyanoalkyl radicals such as cyanoethyl, cyanopropyl and cyanobutyl. Radicals that preferably represent R are ζ. Β Alkyl radicals having 1 to 8 carbon atoms, such as methyl, ethyl, propyl, butyl, pentyl; Aralkyl radicals with 7 to 13 carbon atoms, such as benzyl and phenethyl; Alkylate residues such as 2-methoxymethyl; Alkyl ester radicals such as 2-acetoxyethyl; Alkyl ketone residues such as 1-butan-3-onyl; Cyan alkyl radicals, such as 2-cyanoethyl. The rest

2
for R are the same as for R.

1 2
The radicals R, R and R, as defined in connection with the above formulas 1 to 5, can be any of the above

Be radicals and in a respective compound they can be the same or different.

A preferred polydiorgano siloxane containing polyalkoxy end groups, which is obtained by the above reaction of the silanol end groups containing diorganopolysiloxane polymer of the formula (5) with the integrated crosslinker / cleaner of the formula (1) becomes has the following formula

1 2
wherein R, R and R have the abovementioned meaning, X is a hydrolyzable removable amino group, e has the value 0 or 2, b has the value 0 or 1 and the sum b + e is 0 or 2 and η is an integer of about 50 to about 2500 inclusive. One such preferred polyalkoxy-terminated diorganopolysiloxane of formula (6) is formed in the RTV composition of the present invention and can be mixed with the other ingredients of the composition of the invention in various ways to form various types of mixtures.

A preferred such mixture is e.g. B. one at room temperature vulcanizable material selected from (i) a mixture of

(a) 100 parts of a silanol-terminated polydiorganosiloxane consisting essentially of chemically linked units of the following formula

R.
R.

(b) at least 5 parts of a silane that has hydroxy functional groups eliminated and has the following formula

^(R \
^(Rlo) 4- (a ₊ b) ^{Si (X)} a '

(c) 0 to 10 parts of a crosslinking silane of the formula

(R ² ) _b

^(RO) (4-b) ^SX

(d) an effective amount of a condensation catalyst and

(ix) a mixture of

(a) 100 parts of a polyalkoxy-terminated polydiorganosiloxane of the formula

^(R0 >

3- (b ₊ e) 6io / _eioU

iΛ ⁽ f ²⁾ »

eioUei (OR ¹

(b) 0 to 10 parts of a crosslinking silane of the formula

^Si

(c) an effective amount of a condensation catalyst,

1 2
where R, R, R and X have the aforementioned meaning, a is an integer from 1 to 3, b has the value 0 or 1, the sum of a + b is 1 to 3, e has the value 0 or 2 , the sum of b + e has the value 0 or 2, η is an integer with a value from about 50 to 25,000 inclusive.

Such a mass can also be produced by adding an integrated crosslinker / cleaner of the formulas (3) and (4) in the

—Te—

Mixture of the above procedure is used. In all cases, a curing accelerator is obtained that is used in an RTV composition for the provides suitable shelf life and curing speed.

The preferred crosslinker of the present invention of the formula

1 2 (2) is methyltrimethoxysilane. Preferably R, R and R are Methyl.

A condensation catalyst must also be present in the mass if it is to crosslink to a density and properties should have, as they are normally associated with silicone rubber compounds. The preferred condensation catalyst is a tin catalyst.

Effective amounts of the condensation catalyst used in the present Invention can be used to facilitate the curing of the RTV compositions are, for. B. 0.001 to 1 part of the catalyst, based on 100 parts by weight of the silanol terminated polydiorganosiloxane of the formula (1). Examples for such tin compounds are dibutyltin dilaurate, dibutylsinndlacetate, Dibutyltin dimethoxide, carbomethoxyphenyltin trisuberate, tin octoate, isobutyltin triceroate, dimethyldibutyrate, Dimethyl tin dineodecanoate, triethyl tin tartrate, dibutylsinn benzoate, Tin oleate, tin naphthenate, butyltin tri-2-ethylhexoate and tin butyrate. Of the tin compounds preferred as condensation catalysts, dibutyl tin diacetate is particular preferred.

Titanium compounds that can be used are e.g. B. 1,3-propanedioxytitanium bis (ethyl acetoacetate), 1,3-propanedioxytitanium bis (acetylacetonate), Diisopropoxytitanium bisiacetylacetonate), titanium naphthenate, tetrabutyl titanate, tetra-2-ethylhexyl titanate, Tetraphenyl titanate, tetraoctadecyl titanate and ethyl triethanolamine titanate. The beta-dicarbonyltitanium compounds, as described in US Pat. No. 3,334,067, used as condensation catalysts in the present invention will.

Zirconium compounds such as zirconium octoate can also be used will.

Further examples of metallic condensation catalysts are lead-2-ethyloctoate, iron-2-ethylhexoate, cobalt-2-ethylhexoate, Manganese-2-ethylhexoate, zinc-2-ethylhexoate, antimony octoate, bismuth naphthenate, Zinc naphthenate and zinc stearate.

Examples of non-metallic condensation catalysts are hexylammonium acetate and benzyltrimethylammonium acetate.

In the organopolysiloxane containing silanol or alkoxy end groups various fillers and pigments can be incorporated, such as titanium dioxide, zirconium silicate, silicon dioxide airgel, Iron oxide, diatomaceous earth, fumed silicon dioxide, Carbon black, precipitated silica, glass fibers, polyvinyl chloride, ground quartz and calcium carbonate. The amounts of Fillers can obviously be used within wide limits in accordance with the intended use of the composition can be varied. So z. B. for some sealing applications the curable composition of the present invention without Filler can be used. In other applications, such as the use of the curable masses as binding material, up to 700 or more parts by weight of filler per 100 parts of the organopolysiloxane to be used. In such applications, the filler can consist of a major number of extending materials such as ground quartz, polyvinyl chloride or mixtures thereof and preferably have a particle size in the range of about 1 to 10yum have.

The compositions according to the invention can also be used as structural seals and sealants are used. The exact amount of filler therefore depends on such factors as that intended Type of use of the organopolysiloxane composition and the type of filler used, d. H. its density and particle size. Preferably, a proportion of 10 to 300 parts of filler,

which can include up to about 35 parts of a reinforcing filler such as fumed silica per 100 parts of an organopolysiloxane containing silanol end groups.

The term "stable" as used in the present application in Connection with the one-component, polyalkoxy end groups Organopolysiloxane RTV composition of the present invention is used, means a moisture-curable mixture, which with the exclusion of atmospheric moisture is essentially remains unchanged and hardens to a tack-free elastomer even after prolonged storage. aside from that "Stable" in connection with the present RTV measures also means that the tack-free time that the freshly mixed Components of the RTV mass under atmospheric conditions show essentially the same as those same mixture of ingredients after putting them in either a moisture-proof or moisture-free container accelerated for an extended time at ambient conditions or for an equivalent period at an elevated temperature has aged.

The term "essentially acid-free" in terms of that obtained from the RTV composition according to the invention by exposure to a The elastomer obtained from atmospheric humidity means by-products having a pKa of 5.5 or more, where 6 or more are preferred, and 10 or more are particularly preferred.

In addition to the above constituents, the mass can also contain further constituents contain, such as · plasticizers, in order to reduce the mass To give modulus, further additives for controlling the shape retention, adhesion promoters, etc. are examples of such additives can be found in DE-OS 33 05 356 and in the earlier patent application P 33 13 451.0.

The mass can be made in a number of ways, but most preferably it is made by mixing the

integrated crosslinker / cleaner with the diorganopolysiloxane polymer containing silanol end groups in one essentially anhydrous manner and then add some additional catalyst for endcoupling. As stated above, however, the reaction mixture is autocatalytic. Other ingredients can then be added in subsequent mixing stages including plasticizers, adhesion promoters, fillers, etc. as described in U.S. application serial no. 347 895. In further mixing stages you can also add excess integrated crosslinker / cleaner, as indicated in the above-mentioned US application, until the minimum amount of integrated material indicated above is found in the total mixture Crosslinker / cleaner is available. This minimum amount is to be determined experimentally.

After the mass is formed, it is placed in moisture-proof containers in a substantially anhydrous manner packaged, stored and distributed in this form. If the mass wants to harden, then the seal of the packaging is broken, the mass is applied and exposed to atmospheric moisture, whereupon it becomes a silicone elastomer hardens, with complete hardening occurring within 24 to hours. The mass can be produced continuously or semi-continuously, as in the latter US application indicated or it can be manufactured in batches.

The invention is explained in more detail below with the aid of examples. All parts given in the examples are parts by weight.

Preferred integrated crosslinkers / cleaners within the framework of formula (1) are:

Methyldimethoxy (di-N-hexylamino) silane Methyl dimethoxy (di-N-methylamino) silane Methyldimethoxyisopropylaminosilane methyldimethyoxy (di-N-butylamino) silane Methyldimethoxy (di-N-isobutylamino) silane Methyldimethoxy (di-N-propylamino) silane Methyldimethoxy (di-N-vinylamino) silane

Preferred tin condensation catalysts for use in the present invention are dibutyl tin diacetate and dibutyl tin dilaurate.

example 1

A 5 liter three-necked flask fitted with a mechanical stirrer, a thermometer reaching into the flask, a water reflux condenser with a nitrogen inlet and two 250 ml pressure equalizing addition funnels was purged with dry nitrogen and filled with 2 liters of hexane and 2 moles (280 parts) of triethylamine . After stirring and purging with nitrogen, the addition funnel was filled with one mole (140 parts) of CH ₃ Si (OCH ₃ J ₂ Cl. The second addition funnel was filled with 1.25 moles (231.8 parts) of di-N-hexylamine While stirring at room temperature and under an N ₂ atmosphere, the CH ₃ Si (OCH ₃ ) _C1 was rapidly added to the mixture in the reaction vessel. The di-N-hexylamine was added dropwise to the rapidly stirring mixture in the reaction vessel over a period of 2% A slightly exothermic reaction was observed, as a result of which the vessel temperature rose from 22 to 35 ° C. Large amounts of solid white triethylamine hydrochloride were formed during the reaction liquid volatiles were removed by rotary evaporation with relaxation under reduced pressure and vacuum filtration gave the desired product, methyldimethoxy (di-N-hexyl amino) silane with a

2ί—

SS-

Boiling point from 113 to 115 ° C / 5 mm Hg and in 92% purity according to gas chromatographic analysis.

The CH ^ -Si (OCH,), -N (hexyl), was then filled with polymer

+4 ^

and Sn catalyst mixed under anhydrous conditions in a Semkit mixer. It became the one described below two stage catalysis used:

In the first stage, which comprised 15 minutes of mixing time at room temperature, 85 parts by weight of a silanol-terminated dimethylpolysiloxane polymer with a viscosity of 3000 centipoise at 25 ° C, 15 parts by weight of an octamethylcylotetrasiloxane-treated fumed silica filler and 2 to 6 parts, as indicated in Table I below, of methyldimethoxydihexylaminosilane. 0.23 part of dibutyltin diacetate and 21 was in the second Katalysierungsstufe into this mixture in the Semkit mixer during a 15 minute mixing time at room temperature by weight of a trimethylsiloxy having Dimethylpolysiloxanpolymers having a viscosity of 100 centipoise at 25 ^C
mixes.

at 25 and a silanol content of 500 to 1500 ppm

After mixing, the RTV masses were packaged in sealed aluminum tubes and stored for 24 hours at room temperature, 24 and 48 hours at 100 ° C before being exposed to a curing environment of room temperature and 50% relative humidity. The speed and degree of curing were determined by the tack-free time (abbreviated to TFT) and measurements of the hardness (durometer) after 24 hours. An acceptable cure is defined by a TFT of £ 30 minutes and a hardness (durometer) after 24 hours of £ 28. The results obtained are shown in Table I below.

Table I.

Results with CH-Si (OCH) «- N (hekyl)

3f 2

Amount of CH ₃ Si (OCH ₃ ) ₂ "-N (hexyl)

(Parts

2.0

2.5

3.0

3.5

4.0 '

Storage 24 h

Storage
Time
(Days) Partial assembly TPT
(min) Duro-
meter - - - - O 25 ° 35 gelled in
pipe 28 27 26th 1 25 ° gelled in
pipe 20th gelled in
pipe 25th 31 p 25 ° 25th 25th 40 gelled in
pipe 30th 1 25 ° 55 20th 29 O 25 ° 50 20th 28 1 25 ° 20th 1 100 ° 15th O 25 ° 15th 1 25 ° 20th 1 100 ° 2 100 ° O 25 ° 1 25 ° 1 100 ° 2 100 ° 2 100 ° 2 100 °

5.0

6.0

* Minimum amount of CH-, Si (OCH -) "- N (hexyl)" to ensure storage stability and to achieve rapid hardening.

Example II

OCH-

I ³

CH- Si—— N— (n-butyl) -

I ' OCH.,

A 5 1 3-necked flask fitted with a mechanical stirrer, a thermometer protruding into the flask, a water reflux condenser with N_ inlet opening and two 250 ml addition funnels was pressurized, dry nitrogen was used rinsed and filled with 2 liters of hexane and 2 moles (280 ml) of triethylamine.

i. After stirring and purging with nitrogen, one addition funnel was filled with one mole (140 parts) of CH ₃ Si- (OCH ₃ J ₂ Cl. 1.25 moles (161.6 parts) of di-N- While stirring at room temperature and under nitrogen atmosphere, the CH ₃ Si (OCH ₃ ) ₂ C1 was rapidly added to the mixture contained in the reaction vessel, and the di-N-butylamine was added dropwise to the rapidly stirring one over a 2 hour period A slightly exothermic reaction was observed which caused the reaction vessel temperature to rise from 22 ° to 35 ° C. During the reaction, large amounts of solid white trxylamine hydrochloride were formed the volatiles were removed by rotary evaporation with relaxation under reduced pressure. Vacuum filtration gave the desired product, methyldimethoxy (di-N-butylami no) silane with a boiling point of 6O ⁰ C / 7 mm Hg and 88% purity, as by gas chromatographic

• Analysis determined.

The aminosilane was then catalyst, filler and tin with polymer mixed in a semkit mixer under anhydrous conditions. A gradual catalysis was used: To 85 parts of the silanol-terminated dimethylpolysiloxane polymer of Example I were given 15 parts of the treated fumed silica filler of Examples I and 2 to 5 parts of the aminosilane as indicated in Table II below. This mixture was in a first mixing stage Mixed for 15 minutes at room temperature.

Another catalysis, comprising 15 minutes of mixing at room temperature in a Semkit mixer, was added to this

■ 3 <?

first mixture 0.23 part of dibutyltin diacetate and 1 part of a trimethylsiloxy-terminated dimethylpolysiloxane polymer with a viscosity of 100 centipoise at 25 C and a silanol content of 500 to 1500 ppm. The hardening results such a composition including accelerated aging and tack free time are in given in Table II below.

Table II

Results with CH ₃ Si (OCH ₃ ) ₂ ~ N (butyl)

Amount of
CH-Si (OCH,) - N-butyl) "
, (Part ref Storage
Time
(Days) Location-
temp. TFT
(min) 24 hours
Duro-
meter - - - 2.0 0 25 ° 25th _ 30th 31 1 25 ° 40 24 gelled in the tube 27 1 100 ° gelled in the tube 55 29 2.7 0 25 ° 20th 40 - 1 25 ° 30th 30th 34 1 100 ° 25th 34 * 4.0 0 25 ° 25th 31 1 25 ° 30th 1 100 ° 15th 2 100 ° 25th 5.0 O 25 ° 1 25 ° 1 100 ° 2 100 °

Minimum amount of CH ₃ Si (OCH ₃ ) ₂ ~ N (butyl) _{2 to} achieve storage stability and rapid hardening.

Claims (28)

Dr. Horst pupil PATENT LAWYER EUROPEAN PATENTATTORNEY 6000 Frankfurt / Main Kaiserstrasse 41 phone
telex telegram Fax machines Bank account
Postal checking account (0611) 235555 04-16759 mapat d main patent frankfurt (0611) 251615 (CCITT group 2 and 3) 225/0389 Deutsche Bank AG 282420-602 Frankfurt / M. Your reference / Your ref. : Our reference / Our ref .: Date : 93O7-6OSi-OO577 March 28, 1984 Dr.Sb./he. General Electric Company 1 River Road
Schenectady, NY / USA Process for producing a one-component, at room temperature vulcanizing silicone rubber compound Claims \1. / Method of making a one-component and essentially acid-free silicone rubber compound that can be vulcanized at room temperature, in which a hardening accelerator is directly incorporated is formed after mixing the ingredients in place, characterized by mixing (a) 100 parts by weight of a polydiorganosiloxane containing silanol end groups, which consists essentially of chemically linked units of the following formula SiO- (b) at least about 4 parts of a hydroxy functional silane having the formula - ■ 2 - (R ² ), 1 i ^(R0) 4- (a + b) ^{Si (X)} a (c) O - 10 parts of a crosslinking silane of the formula ⁽ f ² 'b (d) an effective amount of a condensation catalyst, where in the above formulas R is selected from optionally substituted monovalent ones Hydrocarbon radicals with 1 to 13 carbon atoms R is an aliphatic organic radical with 1 to 8 carbon atoms, selected from the group consisting of alkyl, alkyl ether, alkyl ketone and alkyl cyan radicals or a monovalent, optionally substituted, hydrocarbon radical having 7 to 13 carbon atoms X is a hydrolyzable amino group, a has the value 1 or 3, b has the value O or 1 and the sum a + b has the value 1 or 2. The method according to claim 1, characterized in that the crosslinking agent is methyltrimethoxysilane. 3. The method according to claim 2, characterized in that R, R 2
and R are methyl groups. 4. The method according to claim 3, characterized in that the condensation catalyst is a tin compound. 5. The method according to claim 4, characterized in that the condensation catalyst is selected from the class consisting of from dibutyltin dilaurate and dibutyltin diacetate. 6. The method according to claim 1, characterized in that the silane to eliminate the functional hydroxyl groups methyldimethoxy (di-N-hexylamino) silane is. 7. The method according to claim 1, characterized in that the silane to eliminate the functional hydroxyl groups methyl methoxydi-N-methylamino) silane is. 8. The method according to claim 1, characterized in that the silane eliminates the functional hydroxyl groups Is methyldimethoxyisopropylaminosilane. 9. Process for producing a substantially acid-free, organopolysiloxane composition vulcanizable at room temperature under essentially anhydrous conditions in which immediately after mixing the ingredients Cure accelerator is formed in place and in which there is an effective amount of a condensation catalyst together with a silanol-terminated organopolysiloxane and a polyalkoxysilane crosslinking agent used, characterized in that 100 parts by weight of the organopolysiloxane containing silanol end groups are added at least about 4 parts by weight of a polyalkoxysilane is added which has both functional hydroxyl groups is eliminated as well as a crosslinking agent and has the following formula - 2. ^(Rio) 4- (b ₊ a) ^{Si (X)} a where R is an allphatic organic radical with 1 to Carbon atoms is selected from the group consisting of alkyl, alkyl ether, alkyl ester, alkyl ketone, and Cyan alkyl radicals or an aralkyl radical with 7 to 13 carbon atoms, R is a monovalent, optionally substituted hydrocarbon radical with 1 to 13 carbon atoms, X is a hydrolyzable amino group, a has the value 1 or 3,
b has the value 0 or 1 and
the sum of a + b is 1 or 3 and an effective amount of a condensation catalyst is then added. 10. The method according to claim 9, characterized in that the crosslinking agent is methyltrimethoxysilane. 11. The method according to claim 10, characterized in that R, R, 2
and R are methyl groups. 12. The method according to claim 11, characterized in that the condensation catalyst is a tin compound. 13. The method according to claim 12, characterized in that the condensation catalyst is selected from the class consisting of dibutyltin dilaurate and dibutyltin diacetate. 14. The method of claim 9. characterized in that the silane eliminates the functional hydroxyl groups Is methyldimethoxy (di-N-hexylamino) silane. 15. The method according to claim 9, characterized in that the silane eliminates the functional hydroxyl groups Is methyl methoxy (di-N-methylamino) silane. 16. The method according to claim 10, characterized in that the silane eliminates the functional hydroxyl groups Is methyldimethoxyisopropylaminosilane. 17. Method of manufacturing a single-component and in essence acid-free, vulcanizable mass at room temperature, which can be hardened to a solid elastomeric state in which a hardening accelerator is formed immediately after mixing the ingredients, characterized in that one under substantially anhydrous conditions at a Temperature in the range of 0-180 ° C stirs a vulcanizable material at room temperature, which is selected is off (i) a mixture of (a) 100 parts of a silanol-terminated polydiorganosiloxane consisting essentially of chemically linked units of the following formula ο ·; π (b) at least about 4 parts of a hydroxyl functional removal silane, which is the following Formula has ^(Rio) 4- (a ₊ b) ^{Si (X)} a '(c) 0-10 parts of a crosslinking silane of the formula ^(Ri0) (4-b) ^Si (d) an effective amount of a condensation catalyst and
(ii) a mixture of (a) 100 parts of a polyalkoxy-terminated polydiorganosiloxane of the formula ^(Rl0) 3- (b _{+ e)} (b) 0-10 parts of a crosslinking silane of the formula f ^{b (Ri} ° »(4-b) ^S1 ' (c) an effective amount of a condensation catalyst, where R in the above formulas is selected from monovalent, optionally substituted hydrocarbon radicals with 1 to 13 carbon atoms, R is an aliphatic organic radical with 1 to 8 Carbon atoms is selected from the group consisting of alkyl, alkyl ether, alkyl ester, alkyl ketone and alkylcyan radicals or alkaryl radicals with 7-13 carbon atoms, R is an optionally substituted monovalent hydrocarbon rest, X is a hydrolyzable amino group, a has the value 1 or 3,
b has the value 0 or 1,
the sum of a + b is equal to 1 or 3, e has the value 0 or 2,
the sum of b + e is equal to 0 or 2 and η is an integer with a value from about 50 to about 2500 inclusive. 18. Method of making a one-component and essentially acid-free silicone rubber compound that can be vulcanized at room temperature, in which immediately after the Mixing the ingredients a curing accelerator is formed in place, characterized in that the following ingredients are mixed with one another: (a) 100 parts of a silanol-terminated polydiorganosiloxane which consists essentially of chemically linked units of the following formula: _D SiO (b) at least about 4 parts of a hydroxyl functional siloxane that has the following formula ? ¹⁰ 4- (x + y + w) A.
W. 1 2
wherein R and R have the abovementioned meaning and A is a radical which consists of simple amine radicals of the following formula R ¹⁰
- I R ¹¹ wherein R and R are individually selected from hydrogen and monovalent hydrocarbon radicals with 1 to 8 carbon atoms, χ varies in the range from 0.0 5 to 2.5, y varies in the range from 0.00 to 2.50, w varies in the range from 0.05 to 1.5 and the sum of x + y + w has a value in the range from 2.10 to 3.00,
(c) 0 to 10 parts of a crosslinking silane of the formula (R ² ) _b ^(R ° '(4-b) ^hl (d) an effective amount of a condensation catalyst, where R is selected from monovalent, optionally substituted Hydrocarbon radicals with 1 to 13 carbon atoms, R is an aliphatic organic radical with 1 to 8 carbon atoms is selected from the group consisting of alkyl, alkyl ether, alkyl ester, alky! ketone and alkyl cyan radicals or aralkyl radicals with 7 to 13 carbon atoms, 2
R is a monovalent, optionally substituted, hydrocarbon radical having 1 to 13 carbon atoms and b has the value 0 or 1. 19. The method according to claim 18, characterized in that the crosslinking agent is methyltrimethoxysilane. 20. The method according to claim 19, characterized in that R, R 2
and R are methyl groups. 21. The method according to claim 20, characterized in that the condensation catalyst is a tin compound. 22. The method according to claim 21, characterized in that the condensation catalyst is selected from the class consisting of dibutyltin dilaurate and dibutyltin diacetate. 23. The method according to claim 18, characterized in that the siloxane eliminates the fractional hydroxyl groups has the following formula ^ ⁰ ** f ^{i 0} 4- (m + n + o)
I 2 ^A o ι 2
where R and R have the abovementioned meaning and A is a simple amine radical of the following formula, R ¹⁰ -LR ¹¹ 10 11
wherein R and R are individually selected from hydrogen and monovalent hydrocarbon radicals with 1 to 8 carbon atoms, m varies in the range from 0.15 to 2.50, η varies in the range from 0.1 to 1.9, ο varies in the range from 0.05 to 2.00 and the sum of m + n + o has a value in the range from 2.10 to 3.00 Has. 24. A method for producing a substantially acid-free, room temperature vulcanizable organopolysiloxane composition under essentially anhydrous conditions in which immediately after mixing the ingredients Curing accelerator is generated in-situ and which contains an effective amount of a condensation catalyst with an organopolysiloxane containing silanol end groups and a polyalkoxysilane crosslinking agent, characterized in that one to 100 parts by weight of the silanol-terminated organopolysiloxane at least about 4 parts by weight of a polyalkoxysilane adds that both eliminates functional hydroxyl groups and is a crosslinking agent and the follow de formula has - ίο - A is a simple amine residue represented by the following formula R ¹⁰
i B ¹¹ wherein R and R are individually selected from hydrogen and monovalent hydrocarbon radicals with 1 to 8 carbon atoms, χ varies in the range from 0.05 to 2.50, y varies in the range from 0.00 to 2.50, w varies in the range from 0.05 to 1.5, the sum x4-y-fw has a value in the range from 2.10 to 3.00, R is an aliphatic organic radical with 1 to 8 carbon atoms is selected from the group consisting of alkyl, alkyl ether, alkyl ester, alkyl ketone and alkyl cyan radicals or aralkyl radicals with 7 to 13 carbon atoms, R is a monovalent, optionally substituted, hydrocarbon radical having 1 to 13 carbon atoms and an effective amount of a condensation catalyst is then added added, resulting in improved stability in the obtained vulcanizable at room temperature Organopolysiloxane obtained. 25. The method according to claim 24, characterized in that the crosslinking agent is methyltrimethoxysilane. 26. The method according to claim 25, characterized in that R, R 2
and R are methyl groups. 27. The method according to claim 26, characterized in that the Condensation catalyst is a tin compound. 28. The method according to claim 27, characterized in that the condensation catalyst is selected from the class consisting of from dibutyltin dilaurate and dibutyltin diacetate. 29. The method according to claim 24, characterized in that the Siloxane to remove the functional hydroxyl groups has the following formula 4- (m + n + o) 2 ^A o 1 2
where R and R are as defined above and A is a simple amine radical of the following formula R ¹⁰ wherein R and R are individually selected from hydrogen and monovalent hydrocarbon radicals with 1 to 8 carbon atoms, m varies in the range from 0.15 to 2.50, η varies in the range from 0.1 to 1.9, ο varies in the range from 0.05 to 2.00 and the sum of m + n + o has a value in the range from 2.10 to 3.00 Has. 30. Method of making a one-component and essentially acid-free, vulcanizable mass at room temperature, which can be hardened to the solid elastomeric state immediately after mixing the ingredients Hardening accelerator is generated in-situ, characterized in that one under essentially anhydrous conditions at a temperature in the range of 0-180 ° C at room temperature stirred vulcanizable material, which is selected from (i) a mixture of (ä) 100 parts of a silanol-terminated polydiorganosiloxane consisting essentially of chemically linked units of the following formula R.
■ SiO—, (b) a stabilizing amount of a siloxane that eliminates functional hydroxy groups, and the following Formula has f ¹⁰ 4- ^A w 1 2
where R, R and R have the meaning below and A is a simple amine residue represented by the following formula R ¹⁰ - Ν -R ¹¹ wherein R and R are individually selected from hydrogen and monovalent hydrocarbon radicals with 1-8 carbon atoms,
χ varies in the range from 0.05 to 2.50, y varies in the range from 0.00 to 2.50, w varies in the range from 0.05 to 1.5 and the sum of x + y + w has a value im Has the range from 2.10 to 3.00, (c) 0-10 parts of a crosslinking silane of the formula (R ² ) _b ^Si (d) an effective amount of a condensation catalyst dators and
(ii) a mixture of (a) 100 parts of a polyalkoxy terminated Polydiorganosiloxane of the formula ^(ßl0) 3- (b ₊ e,,
^Χ β (b) 0-10 parts of a crosslinking silane of the formula (R ² ) _b ^Si (c) an effective amount of a condensation catalyst / where R is selected from monovalent, optionally substituted Hydrocarbon radicals with 1-13 carbon atoms, R is an aliphatic organic radical with 1-8 carbon atoms selected from the group consisting of alkyl, alkyl ether, alkyl ester, Alkyl ketone and alkyl cyan radicals or alkaryl radicals with 7-13 carbon atoms, R is an optionally substituted monovalent hydrocarbon radical with 1 to 13 carbon atoms is, X is a hydrolyzable amino group, b has a value of 0 or 1, e has a value of O or 2, the sum b + e is equal to 0 to 2 and η is an integer with a value from about 50 to 2500 inclusive . 31. The method according to claim 30, characterized in that the Hydroxyl Functional Siloxane has the following formula I- (m + n + o) 2 A O 1 2
wherein R and R have the abovementioned meaning and A is a simple amine radical of the formula E ¹⁰ - I - R ¹¹ wherein R and R are individually selected from hydrogen and monovalent hydrocarbon radicals with 1 to 8 carbon atoms, sn varies in the range from 0.15 to 2.50, η varies in the range from 0.1 to 1.0, ο varies in the range from 0.05 to 2.00 and the sum of m + n + o has a value in the range from 2.10 to 3.00 Has.