FR2543559A1 - PROCESS FOR PRODUCING A SILANE RUBBER COMPOSITION VULCANIZABLE AT AMBIENT TEMPERATURE TO A COMPONENT - Google Patents

Abstract

THE INVENTION RELATES TO A PROCESS FOR MANUFACTURING A COMPOSITION OF RUBBER SILANE VULCANIZABLE AT ROOM TEMPERATURE TO ONE COMPONENT, IN WHICH A CURING ACCELERATOR IS FORMED IN SITU. THE PROCESS CONSISTS OF MIXING: A.100 PARTS BY WEIGHT OF A POLYDIORGANOSILOXANE WITH SILANOL TERMINAL GROUPS; B. AT LEAST APPROXIMATELY FOUR PARTS OF A SILANE CLEANER FOR HYDROXY-FUNCTIONAL GROUPS; C.0 OR 10 PARTS OF A CROSS-LINKING SILANE; AND D. AN EFFECTIVE QUANTITY OF A CONDENSATION CATALYST. THE COMPOSITION OBTAINED HAS A PERIOD OF TRANSFER TO A NON-STICKY CONDITION WHICH IS NOT AFFECTED BY AN EXTENDED STORAGE TIME.

Description

M 543559

  The present invention relates to one-component alkoxy-functional room temperature vulcanizable silicone rubber (VTA) compositions and, more particularly, relates to

  VTA silicone rubber with an alkoxy component

  functionalities in which an accelerated

hardening.

  One-component VTA silicone rubber compositions have long been known. Older ones have been acyloxy functional; that is, the agent of

  crosslinking was acyloxy-functional Such a composition

  tion was conditioned in the substantially anhydrous state in a container to a package or component when

  it was desired to harden the composition, to open the

  Exposure to atmospheric moisture caused curing of the composition to give a silicone elastomer. More recently, alkoxy functional VTA compositions or VTA desilicone rubber compositions have been developed. that is, the crosslinking agent is an alkoxyfunctional silane such as methyltrimethoxysilane. An example of such a composition which has been marketed is described in US Pat. No. 4,100,129 to Beers Une

  such a composition consists of a diorgano-

  polysiloxane with silanol end groups, a

  trialkoxysilane crosslinking of a condensation catalyst

  consisting of a titanium chelate, a charge and various

other additives.

  Although the composition according to the aforementioned patent has been marketed and has a shelf life of one year or more, as well as a curing speed compatible with commercial requirements, the fact remains that it causes certain problems. some batches of such composition, it was found that the useful life could be affected to such a point that the composition deteriorated considerably after one or two months of storage In fact, it has been found that in most cases the The useful life of these compositions was affected even after two months of storage. In addition, it was found that in some batches of these compositions the curing rate was not commercially acceptable. Various improvements were made to these compositions. Scompositions, and although the problems have been some

  little reduced, they have not been eliminated completely.

  U.S. Patent Application No. 2,777,524 to White and discloses a rubber composition of

  VTA silicone with a perfected alkoxy-functional component

  marketed and marketed. According to the description of this

  patent application, the non-bonded hydroxy groups of the VTA composition would cause a degradation of the alkoxy groups carried by the terminal silicon atoms of the basic diorganopolysiloxane polymer. It is furthermore supposed that this degradation of the alkoxy groups results.

  by a gradual deterioration of the hardening speed

  As a result, US Patent Application 277,524 to White et al supra discloses a rubber composition.

  VTA silicone to an improved alkoxy functional component

  that is to say, offering better storage stability and a better cure speed in

  using, in these compositions, certain agents "net-

  These silane cleaners react with the unbound hydroxy groups of the VTA mixture so as to fix them and prevent them from degrading the terminal alkoxy groups of the basic diorganopolysiloxane polymer. The service life and cure rate of the composition are preserved even after prolonged storage. The useful life of a commercially acceptable silicone rubber composition VTA must be such that, after storage for periods of up to 6 to 12 months from manufacture, it goes to the non-stick state in 120 minutes or less. A composition that is preferred is a composition of

  silicone rubber VTA to an alkoxy-functional component

  which after storage in an anhydrous state in a package for a period of up to one year

  or more, goes to the non-sticky state in 60 minutes or less.

  Such compositions are described in US Patent Application 277,524 White et al supra. It is stated in this patent application that the group

  The functional silane cleaner may be an amino group.

  It is also indicated that it is possible to use a hardening accelerator chosen between

amines and guanidines.

  It is also important to note United States Patent Application No. 462,949 to Mitchell which discloses the use of certain amino-functional alkoxy-functional siloxane cleaners or integrated cleaner-crosslinking agents on VTA silicone rubber compositions. to an alkoxy-functional component similar to those described in US Patent Application No. 277,524 in the name of White et al. In this US Patent Application 277,524 in the name of White et al, it is stated that the curing accelerator can be used at a concentration of 0.1 to parts and preferably 0.1 to 1 part and better 0.3 to 1 part, per 100 parts of silanol end-group diorganopolysiloxane polymer. It is further indicated that with such curing accelerator concentrations, the composition becomes non-tacky in less than 10 parts. 60 minutes after the uncured composition was accelerated and exposed to moisture This patent application further indicates that the cleaner crosslinking agent is used with an excess of 3% by weight based on the base polymer; the excess in question for "capping" the silanol end-group diorganopolysiloxane polymer According to US Patent Application No. 277,524 to White et al., it is desirable to add up to 0.5 parts of integrated crosslinking cleaner for capping the base polymer; to do this, add a maximum of 3 parts by weight of integrated cleaner crosslinker for cleaning purposes; and to do this, generally add from 0.1 to 5 parts, and more preferably from 0.3 to 1 part of one of the amine curing accelerators per 100 parts by weight of the diorganopolysiloxane base polymer to

silanol end groups.

  It has now surprisingly been found that instead of adding a separate integrated cleaner crosslinker and a separate curing accelerator, it is sufficient to add a

  crosslinking cleaner built-in when the latter is amino-

  functional, a primary or secondary amine being released in sufficient quantity to act as a hardening accelerator. The present invention therefore aims to provide a

  in situ formation process of a hardening accelerator

  in a silicone rubber composition VTA to an alkoxy-functional component. It is also intended to provide a process for producing in situ an aminofunctional curing accelerator by reacting an aminofunctional integrated cleaner crosslinking agent with a polymer of

  diorganopolysiloxane with silanol end groups.

  It also proposes to provide a process for the in situ production of an amino-functional curing accelerator, in a VTA silicone rubber composition with an alkoxy-functional component, by reacting an integrated crosslinking agent.

  primary and secondary amine with a diorgano-

  polysiloxane with silanol end groups.

  Still another object of the invention is to provide a process for producing a silicone VTA rubber composition with an alkoxyfunctional component by producing in situ an aminofunctional cure accelerator which results in the production of a final uncured composition passing through. in the non-tacky state in 60 minutes or less after

  storage periods of one year or more.

  These and other objects are satisfied by the invention as described below: In view of the above stated purposes, this

  invention provides a method of manufacturing a composition

  silicone rubber substantially free of acid to a component in which a curing accelerator is produced in situ, immediately after

  mixing of the components, said method comprising mixing

  to 100 parts by weight of a polydiorganosiloxane having silanol end groups, essentially consisting of chemically combined units of formula

R

-If O

  R B at least 5 parts of a silane cleaner for hydroxyfunctional groups of formula

12

  (R 2) (R 10) 4- (a + b) Si (X) a (1) C 0 to 10 parts of a crosslinking silane of formula (R 2) blb (R o) (4-b) i (2 and D an effective amount of a condensation catalyst, wherein R is selected from substituted or unsubstituted monovalent hydrocarbon radicals having from 1 to 13 carbon atoms, R is an aliphatic organic radical having from 1 to 8 atoms of carbon chosen from alkyl, alkyl ether, alkyl ester, cetoalkyl, cyanoalkyl, or an aralkyl radical having 7 to 13 carbon atoms, R 2 is a substituted or unsubstituted monovalent hydrocarbon radical having from 1 to 13 carbon atoms, X is a hydrolysable, and a is an integer equal to 1 or 3, b is an integer

  equal to 0 or 1, and the sum of a + b is equal to 1 or 3.

  The compound of formula 1 is an integrated cleaner crosslinking agent wherein X is a primary or secondary amine and preferably a secondary amine. The secondary amines, which are released upon reaction of the integrated cleaner crosslinking agent of formula 1 and then

  the styling of the diorganopolysiloxane polymer with

  Silanol terminal compounds act as end-of-pipe coupling catalysts and additionally as curing accelerators.

same way.

  If desired, an excess of crosslinking agent of formula 2 is added to the composition, such that it grabs to the ends of the diorganopolysiloxane polymer with basic silanol end groups as many groups.

  alkoxy terminals that it is possible.

  Whether it is a silane or a siloxane, the integrated cleaner crosslinking agent, when it reacts with the silanol groups of the diorganopolysiloxane polymer, releases primary or secondary amines as indicated above which behave as a coupling catalyst at the end of the chain, catalyzing this coupling between the silanol end-group diorganopolysiloxane base polymer and the integrated cleaner crosslinking agent and which also act as a hardening accelerator to maintain the time required for the passage of the composition non-tacky state at a value, preferably less than 30 minutes after the composition has been stored for periods of up to 1 year or longer The most preferred crosslinking agent is methyltrimethoxysilane

  and the preferred silane cleaner is methyl-

  dimethoxy (di-N-hexylamino) silane. In addition, for the composition to cure with the properties usually associated with silicone rubber compositions VTA, it is necessary that the composition contains a condensation catalyst and, more particularly, a tin condensation catalyst which is, for example dibutyltin dilaurate or

diacetate dibutyltin.

  As indicated above, per 100 parts of silanol terminated diorganopolysiloxane polymer, there should be at least about 4 parts of integrated cleaner crosslinking agent to give a commercial product, i.e., a product having such stability that after storage for 6 to 12 months, it goes to the non-tacky state in minutes or less Preferably, the alkoxy-functional component VTA composition has a storage stability such that it can be stored for a year or more and pass, at the end of this period, in the non-tacky state in minutes or less To obtain such storage stability, it is necessary to have about 5 parts to 7 parts of crosslinking agent built-in cleaner for 100

  parts of the diorganopolysiloxane base polymer with

  Silanol end-pieces More than 7 parts of integrated cleaner-crosslinking agent can be used, but without any useful effect. It should be noted that the lower limit of 4 parts has been experimentally determined with the integrated crosslinking agent of Example 1 This lower limit changes somewhat with the different types of crosslinking agent built-in amino-functional Nels For this reason, in the present

  description and in the examples, we speak about 4

  at least parts of cleaner crosslinking agent incorporated in the composition Di-N-hexylamine is a secondary amine which is one of the most effective and which is preferred as

  hardening accelerator It should be noted that the

  N-hexylamine which is released in Example 1 as

  In situ curing accelerator is an accelerating

  Thus, the results of Example 1 reflect the lower limit for which the integrated crosslinking agent effectively produces an alkoxy-functional silicone VTA rubber composition which in situ forms an accelerator. curing to yield a composition having a storage stability and a suitable non-tacking time of transition Other amines liberated at

  from the crosslinking agent cleaner may be slight-

  Therefore, the amount of at least about 4 parts indicated corresponds to the minimum concentration of integrated crosslinking agent that is required in the composition to produce a curing accelerator for curing the composition at an appropriate rate. It should be noted that this effect is not cumulative since it could not be expected from the use of the individual additives to the composition described on page 13 of US Patent Application No. 277,524 White et al. In this application, it is stated that the curing accelerator is a separate compound which is not formed in situ but which is added to the composition whereas the minimum amount would be 4 parts of integrated cleaner crosslinking agent. It is mixed or formed. On page 10 of the patent application in question, it is indicated that up to 3

  % by weight of excess cleaner in the composition.

  In the experiment reported in Example 1 of the present application, at least about 4 parts of integrated cleaner-crosslinking agent were used to obtain a commercially usable composition per 100 parts of silanol-terminated diorganopolysiloxane polymer. It was only necessary to use 0.33 part of integrated cleaner crosslinking agent to completely stop the chains of the diorganopolysiloxane polymer to

  This is the theoretical value.

  Such an amount of integrated cleaner crosslinking agent

  releases about 0.12 parts of di-N-hexylamine as accelerated

  curing agent According to the description of the application

  US Pat. No. 2,757,524 to White et al., when the curing accelerator is added as a separate component and the integrated cleaner crosslinking agent is also added as a separate component to the composition, it appears that maximum there can be 3.5

  parts of crosslinking agent incorporated in the composition.

  However, as shown by the experimental results of Example 1, it was necessary to have at least about 4 parts of cleaner crosslinking agent incorporated into the composition, at a minimum, to produce a commercially usable VTA composition; that is to say a composition having a useful life and a transit time to

  commercially acceptable non-sticky condition.

  In short, what one wishes to bring out from the discussion above is that the effect of the in situ formation of the hardening accelerator is not cumulative as one might expect from the demand US Patent No. 277,524 in the name of White et al, but to be determined experimentally At no time does US Patent Application No. 277,524 in the name of White et al., or any other patent, describe in situ formation. of a hardening accelerator and the compositions according to the invention In this prior application, as well as in

  any other patent application, the hardening accelerator

  This is a separate compound which is added to the composition during the mixing process. One of the advantages, which is the fundamental advantage of the composition according to the invention, is that it allows easier formation of the composition continuously. ; that is, only one component is needed, not two separate components, which facilitates the production of the composition by continuous mixing of the components in an extruder where volatiles are removed as described in U.S. Patent Application No. 437,895 to Chung et al. This is particularly true in the case of the integrated cleaner crosslinking agent which is used in the composition in relation to what would be if we used a

  separate curing accelerator added to the composition.

  Accordingly, the fundamental advantage of the process according to the invention is to facilitate the production of the alkoxy-functional VTA composition and, more particularly, the

  formation or continued manufacture of such a composition

  ion. Turning now to the compound of formula 1, such a compound is well known to have been described in US Patent Application No. 277,524 to White and Ai. This compound is not only a crosslinking agent cleaner. integrated, according to White et al, but an integrated cleaner crosslinking compound which may comprise a single alkoxy group attached to the silicon atom Thus, it is possible to form from such compositions

  integrated crosslinking agents, diorganopolymers

  siloxane having only one alkoxy group on a terminal silicon atom and also one or two amine groups on a terminal silicon atom of the polymer chain Ces

  compositions fall within the scope of the invention and

  The formation of such base polymers is also described in US Patent Application No. 449,105 in the name of Lucas The compounds of Formula 1 are described in this application Lucas more completely than in the White application which indicates that the integrated crosslinking cleaners must have at least 2 alkoxy groups. Therefore, whether the white or Lucas-based integrated cleaning crosslinking agents are used, a polymer is formed whose chain ends are stopped and in which the silicon atoms are formed. terminals carry 1, 2 or 3 alkoxy groups and which, according to the present invention, form an accelerator of hardening in situ and leads to a composition having a stability

  storage and a suitable cure rate.

  It should also be noted that while the integrated cleaner crosslinking agent of Formula 1 terminates the chains of the silanol terminated diorganopolysiloxane polymer, the amines which are released and can be either

  primary or secondary, also act as catalysts

  End-Coupling Coupler According to U.S. Patent Application No. 277,524 White et al. Additional end-of-chain coupling catalysts can be used as described in U.S. Patent Application No. 427,930 Chung et al. As described above, the crosslinking silane of formula 2 can be used in the composition as an optional crosslinking agent to ensure that a

  maximum chain stoppage on the diorgano-

  The silanol terminated polysiloxane and also obtain a high crosslinking density in the composition. Alternatively, either in combination or as a replacement for the built-in cleaner crosslinking agent formed from a silane of formula I, a crosslinking agent integrated cleaner of formula R 2 ô y (R 1) x SiO 4 _Xyw 3 A w

1 2

  in which R and R are as defined above and A is a single amino radical of the formula R 10

? N R 11

  in which R 10 and R 1 are identical or different and chosen from hydrogen and monovalent hydrocarbon radicals having 1 to 8 carbon atoms, x is between 0.05 and 2.50, y is between 0.00 and 2.50, W is between 0.05 and 1, S, and the sum of x + + W is

between 2.10 and 3.00.

  The compounds of formula 3 differ from the compounds of formula 1 in that they are siloxanes which nonetheless constitute integrated crosslinking agents. Such compounds have at least one alkoxy group and 2 to 20 silicon atoms. The amino group -Functional of such siloxanes of formula 3 is derived from a single primary amine or a secondary amine A crosslinking agent

  integrated cleaner formed of an amino-functional siloxane that -

  it is preferred to have the formula R 2 n (RO 0) m Si 4- (m + n + o) (4)

-2

  Wherein R 1 and R 2 are as previously defined and A is a single amino radical of the formula R 10 R 11 NR in which R 1 and R 1 are the same or different and selected from hydrogen and monovalent hydrocarbon radicals having 1 to 8 carbon atoms, m is from 0.15 to 2.50, N is from 0.1 to 1.9 and o is from 0.05 to 2.00, the sum of -m + N + o being

between 2.10 and 3.00.

  The compounds of formula 4 constitute integrated crosslinking agents consisting of siloxanes forming part of formula 3 which comprises at least three alkoxy groups in the polymer part. These compounds have from 2 to 20 silicon atoms in the polymer chain. the amino functional groups, the compounds of formula 4 must have at least the same number, that is to say an amine group in the polymer part but, at most, they may have more amine groups in the part only possible with the compound of formula 3. As a result, these compounds of formula 4

  the integrated cleaner-crosslinking agents that are preferred.

  For further details on the formation of the compounds of Formula 3 and 4 and their use in the production of VTA silicone rubber compositions with an alkoxy-functional component, reference may be made to U.S. Patent Application No. 462,949 in the name of Mitchell The compounds described in this patent application are the same

  than those mentioned in the present description, with

  that, at present, the purpose of the addition of the aforementioned amounts of cleaner crosslinking agent integrated in the composition is to produce an accelerator of hardening in situ in this composition The only opposition is that with such compounds, in particular with those of high molar mass having a small number of amine groups, it is necessary to use a considerably larger amount of these compounds as cleansing crosslinking agents incorporated in the composition with respect to the minimum level of about 4 parts, as indicated above, for the

  the simplest amines of formula 1.

  The compounds of formulas 1, 3 and 4 are described in the aforementioned U.S. Patent Application Nos. 277,524 to White et al., 449,105 to Lucas and 462,949 to Mitchell and their use as a crosslinking agent.

  integrated cleaner, is largely explained in these applications.

  It is only necessary that these components be mixed with the composition in the amounts indicated above to enable them to act, not only as an integrated cleaner crosslinking agent, but also as a pure cleaning component so as to produce in situ primary or secondary amine curing which improves the curing rate of the composition. The diorganopolysiloxane polymer with silanol end groups preferably corresponds to the formula

1

  HO t Si O H () R n in which the radicals R identical or different, are

  chosen from the monovalent hydrocarbon radicals sub-

  substituted or unsubstituted compounds having from 1 to 13 carbon atoms, which radicals are preferably methyl radicals or a mixture of a major amount of methyl radicals and a minor amount of phenyl, cyanoethyl, trifluoropropylvinyl radicals and mixtures thereof; and N is an integer of from about 50 to about 2500. Preferably, the polymer has a viscosity of from 100 to about 400,000 centipoise and more preferably a viscosity of from about 1,000 to about 250,000 centipoise at about 25 ° C. the index N of formula 5

is between 500 and 2,000.

  The radicals designated R in formulas 1, 2 and are, for example, aryl radicals and aryl radicals.

  halogenated compounds, such as phenyl, tolyl, chloro

  phenyl, naphthyl; aliphatic and cyclic radicals

  aliphatics, for example cyclohexyl radicals, cyclohexyl

  butyl; alkyl and alkenyl radicals, such as methyl, ethyl, propyl, chloropropyl, vinyl, allyl, trifluoropropyl radicals; and cyanoalkyl radicals, by

  for example, cyanoethyl, cyanopropyl and cyanobutyl radicals.

  Preferred radicals for R 1 are, for example, alkyl radicals having 1 to 8 carbon atoms, including methyl, ethyl, propyl, butyl, pentyl; aralkyl radicals having 7 to 13 carbon atoms, for example the benzyl radical; the phenethyl radical; the

  alkyl ether radicals such as the methoxy-2- radical

  ethyl; alkyl ester groups, for example 2-acetoxyethyl groups; alkyl ketone radicals, by

  for example the butan-3-onyl-1 radical; cyano radicals

  Alkyl, for example the cyano-2-ethyl radical. The radicals designated R may be the same as those designated R. The radicals R, R 1 and R 2 are as defined in the formulas above, that is, to say can be identical or

  different in formulas 1, 2, 3, 4 and 5.

  A polydiorganosiloxane with poly-

  Preferred alkoxy produced by the above reaction of the silanol terminated organopolysiloxane polymer of formula 5 with the integrated cleaner crosslinking agents of formula I has the formula (R) b R (R) b (R'O) SiO SO SO ( OR ') (R)) 3- (b + e) 1 i O 3- (b + e) (6) i 2 Xe N Xe wherein R, R 1 and R 2 are as previously defined, x is a hydrolyzable amino seccable group, e is an integer of 0 or 2, b is an integer of 0 or 1, the sum of b + e being 0 or 2; and N is an integer having a value of between about 50

  and about 2,500, inclusive limits Such diorganopolys-

  Preferred polyalkoxy terminated siloxane of formula 6 is preferably formed in the VTA compositions according to the invention and may be mixed with the other components of the composition in various ways to

  form different types of mixtures.

  A preferred mixture is, for example, a room temperature vulcanizable material consisting of: a mixture comprising: a) 100 parts of silanol end group polydiorganosiloxane formed essentially of chemically combined units of the formula Sio- b) at least 5 parts of a silane cleaner for functional hydroxy groups and having the formula (R 2) b (R 1) 4 (a + b) Si (X) c) 0 to 10 parts of a crosslinking silane of formula (R 2) b ( R 10) (4 _b) If d) an effective amount of a condensation catalyst, and 2 a mixture comprising: a) 100 parts of a polydiorganosiloxane having polyalkoxy terminal groups of formula (R 10) 3 (b + e) 353-be (R) b R SiO Si ll Xe R e (R) b Si (OR 1 3- (b + e) 3 b) 0 to 10 parts of a crosslinking silane of formula (R) bs 1 (RO) (4 b) Si (4-b)

  (c) an effective amount of a condensing agent,

  mules in which R, R, R and x are as previously defined; a is an integer between 1 and 3 inclusive; b is an integer equal to 0 or 1, and the sum of a + b is between 1 and 3; e is an integer of 0 or 2, and the sum of b + e is 0 or 2; N is an integer having a value of between about 50 and

2,500, terminals included.

  Such a composition can be produced by using an integrated cleaner crosslinking agent of formula 3 or 4 in the mixture according to the method above. In all cases, a cure accelerator is formed which provides a VTA composition having storage stability and speed. The preferred crosslinking agent according to the present invention and having formula 2 is methyltrimethoxysilane.

  radicals R, R 1 and R 2 are methyl radicals.

  In addition, it is necessary that the composition contains a condensation catalyst if it is to cure with a desired crosslinking density and if it must have the desired crosslinking density.

  properties normally associated with rubber compositions

  silicone rubber The condensation catalyst that we

  Preferably is a tin condensation catalyst.

  The effective amounts of condensation catalysts that can be used for the implementation of this invention

  invention to facilitate the hardening of composi-

  VTA values are, for example, between 0.001 and 1 part by weight per 100 parts of polydiorganosiloxane with 8 silanol end groups of formula 1.

  tin include, for example, dibutyl dilaurate

  tin, dibutyltin diacetate, dibutyltin dimethoxide, carbomethoxyphenyltin trisuberate, tin octoate, isobutyltin triceroyl, dimethyltin dibutyrate, dimethyltin di-neodecanoate, triethyltin tartrate, dibutyltin dibenzoate,

  tin oleate, tin naphthenate, tri (ethyl-2-

  hexylate) butyltin, and tin butyrate The preferred condensation catalysts are tin compounds and especially dibutyltin diacetate. The titanium compounds that can be used are

  for example, propane-i, 3-dioxythobutylacetoacetate

  titanium, propane-1,3-dioxytitanium bis (acetylacetonate),

  bis (acetylacetonate), diisopropoxytitanium, naphthenate

  titanium, tetrabutyl titanate, tetra (2-ethylhexyl) titanate, tetraphenyl titanate,

  tetraoctadecyl titanate, and ethyl titanate

  In addition, it is possible to use betadicarbonyltitanium compounds, as described in the US Pat.

  United States No. 3,334,067 in the name of Weyenberg, as a catalyst

condensation.

  It is also possible to use zirconium compounds

for example, zirconium octoate.

  Other examples of metal condensation catalysts include lead ethyl-2-octoate, iron ethyl-2-hexoate, cobalt ethyl-2 hexanoate, manganese ethyl-2-hexoate zinc ethyl-2-hexoate,

  antimony octoate, bismuth naphthenate, naphtha-

  zinc nate and zinc stearate.

  Examples of non-metallic condensation catalysts include hexylammonium acetate and

  benzyltrimethylammonium acetate.

  Various fillers and pigments may be incorporated into the organopolysiloxane with silanol or alkoxy end groups, such as, for example, titanium dioxide, zirconium silicate, silica airgel, iron oxide, diatomaceous earth, fumed silica, carbon black, precipitated silica, glass fiber, poly (vinyl chloride), ground quartz, calcium carbonate, etc. The amounts of filler used may obviously vary within However, in some sealing applications, the curable compositions according to the present invention may be load-free. In other applications, such as the use of the curable compositions for making bonding materials, can use on a weight basis amounts up to 700 parts or more of filler per 100 parts of organopolysiloxane In such applications, the filler is e mostly dilution materials such as ground quartz, poly (vinyl chloride) or mixtures thereof, preferably having a size of

  particles average between about 1 and 10 microns.

  The compositions according to the present invention can also be used in the manufacture of sealing and sealing products for the construction

  The exact amount of charge therefore depends on factors such as the applica-

  where the organopolysiloxane composition is intended, the type of filler used (i.e. the charge density and its particle size). Preferably, a proportion of from 10 to 300 parts of filler is used. may include up to about 35 parts of reinforcing filler such as fumed silica, per 100 parts

  of organopolysiloxane with silanol end groups.

  As used herein, the term "stable" applied to the one-component polyalkoxy end-group organopolysiloxane VTA composition means a moisture-curable blend capable of remaining substantially unchanged while being protected. of atmospheric moisture and which is capable of curing to give a non-tacky elastomer after a prolonged storage period In addition, a stable VTA composition also means that the time of non-sticking of a VTA composition whose components that have just been mixed under atmospheric conditions is substantially the same as that of the same mixture of components exposed to moisture-atmospheric after being held in a moisture-resistant package, and not enclosing it, not for a period of time. extended storage period under ambient conditions or during an equivalent period during a hardened accelerated

high temperature

  The expression "substantially free of acid" used

  with respect to the elastomer obtained from the VTA composition according to the present invention, when

  exposure to atmospheric moisture, means the production of

  by-products having a p Ka of 5.5 or more,

  preferably 6 or more and better 10 or more.

  In addition to the aforementioned components, the composition may contain other components such as plasticizers to give it a low modulus, additives to prevent sagging, and adhesion promoters, etc. Examples of such additives are described in the U.S. Patent Nos. 349,537 to Beers and 349,538 Lucas The composition may be prepared in a variety of ways, but preferably it is prepared by mixing the agent.

  crosslinking cleaner integrated with the diorgano-

  polysiloxane with silanol end groups under substantially anhydrous conditions, after which any coupling catalyst is added at the end of the chain

  However, the reaction mixture is self-reactive

  catalytic as previously indicated Then, during the subsequent mixing steps, other components may be added, including -plasticizers, adhesion promoters, fillers, etc. as described in US Patent Application No. 347 895 in the name of Chung et al In the course of the additional mixing steps, it is also possible to add an excess of integrated cleaner crosslinking agent as described in this same Chung patent application, it being understood that the total mixture must comprise at least the minimum amount. of the above-mentioned integrated cleaner crosslinking agent The minimum amount of a particular integrated crosslinking agent has to have been

determined empirically.

  Once the composition is formed, it is conditioned to substantially anhydrous condition in moisture resistant packages and stored and sold

  As it stands When you want to harden the composi-

  The package is opened and the composition is applied and exposed to atmospheric moisture, resulting in its curing into a silicone elastomer whose total cure takes 24 to 72 hours. As noted above, this composition can be prepared in the following manner. continuous or semi-continuous, as described in United States Patent Application No. 347,895 Shung where it may be

  produced or mixed in batches if desired.

  The most preferred integral cleaner crosslinking agents within the scope of Formula 1 are: methyldimethoxy (di-N-hexylamino) silane methyldimethoxy (di-N-methylamino) silane methyldimethoxyisopropylaminosilane methyldimethoxy (di-N-butylamino) silane methyldimethoxy (di-N-isobutylamino) silane methyldimethoxy (diN-propylamino) silane

  methyldimethoxy (di-N-vinylamino) silane.

  The tin condensation catalysts which are preferred for use according to the present invention are

  dibutyltin diacetate and dibutyl dilaurate

  tin. In the examples that follow, the quantities indicated

  in parts are parts by weight.

EXAMPLE 1

  The anhydrous nitrogen was purged and charged with 2 liters of hexane and 2 moles (280 parts) of Et 3 N and a 5 liter three-necked flask equipped with a mechanical stirrer, a thermometer, a condenser. water reflux with a nitrogen inlet, and two 250 ml introduction flasks for the equalization of the pressure After stirring and purging with nitrogen, an introduction funnel was charged with 1.00 mol ( 140 parts) of

  CH 3 Si (OCH 3) 2 C 1 The second introductory light bulb

  with 1.25 moles (231.8 parts) of di-N-hexyl-

  Amine While stirring at room temperature under a nitrogen atmosphere, the CH 3 Si (OCH 3) 2 Cc was rapidly added to the reaction mixture. Di-N-hexylamine was added dropwise to the reaction mixture, which was rapidly stirred on a two-hour period A slight exotherm occurs which causes the reactor temperature to rise from 22 ° C. to 35 ° C. Copper amounts of solid and white triethylamine hydrochloride are formed during the reaction. After stirring at room temperature for hours the solids are removed by vacuum filtration and the volatile volatiles are removed by rotary flash evaporation under reduced pressure. Vacuum filtration gives the expected product, namely the

  methyldimethoxy (di-N-hexylamino) silane, having a point of

  boiling 113-115 ° C / 5 mm Hg and 92% purity

  determined by gas chromatographic analysis.

  The CH 3-Si (OCH 3) 2-N (hexyl) 2 is then mixed with the polymer, the feedstock and the Sn 4 + catalyst in

R

  Anhydrous conditions using a Semkit R mixer Two steps of catalysis were carried out, as indicated below. In the first step which includes a mixing time of 15 minutes at room temperature, 85 parts by weight of silanol endblocked dimethylpolysiloxane polymer having a viscosity of 3000 centipoise at 25 C were mixed with 15 parts by weight of a fumed silica feed treated with octamethylcyclotetrasiloxane and 2 to 6 parts, as indicated in Table 1 below, methyldimethoxydihexylaminosilane This mixture is taken up and, in a second catalytic step in the mixer R Semkit R, and it is added during a mixing period of 15 minutes at room temperature, 0.23 part of dibutyltin diacetate and 21 parts by weight of polymer

  dimethylpolysiloxane with trimethyl-

  siloxy having a viscosity of 100 centipoise at 25 C and a silanol content of between 500 and 1500 parts per million.

  After mixing, the VTA compositions are conditioned

  born in sealed aluminum tubes and stored for 24 hours at room temperature, 24 hours at 1000 C and 48 hours at 1000 C before being exposed to a curing atmosphere with an ambient humidity of 50% at the Ambient temperature The rate and degree of curing were determined by the non-tacking time and the durometer reading after 24 hours. Acceptable curing is defined as a lower-tacking time-to-no-slip time. equal to 30 minutes and a durometer value after 24 hours greater than or equal to 28 The results are given in Table 1

TABLE 1

  Results with CH 3 Si (OCH 3) 2-N (hexyl) 2 Rate in Time TV TPENC Durometer CH Si (OCH) 2-N (hexyl) 2 Stock (C) (min) (24 h) (patties) ( days)

2.0 O 25 35 -

1 gelling in the tube

2.5 O 25 25 -

gelation in the tube

3.0 O 25 20 -

1 25 25 28

1,100 gelation in the tube

3.5 o O 25 40 -

1 25 55 27

  i 100 50 25 2 100 gelling in the tube

4.0 * O 25 20 -

1 25 20 26

1 100 20 31

3 O

* 2 100 15 30

, 0 2 100 15 29

6.0 2 100 20 28

  Minimum rate of CH 3 Si (OCH 3) 2-N (hexyl) to obtain 3 i 013) 2-Nhx 12

  storage stability and fast curing.

  T V = aging temperature

  TPENC = time of transition to non-sticky state.

EXAMPLE 2

  OCH 9 3 CH Si N- (n-butyl) 2 3 OCH 3 Anhydrous nitrogen was purged and charged with 2 liters of hexane and 2 moles (280 ml) of Et 3 N and a 5 liter tricol a mechanical stirrer, a thermometer and a reflux condenser of water, with a nitrogen inlet and 2

  250 ml pressure equalizing ampoules.

  After stirring and purging with nitrogen, an introduction funnel was charged with 1.00 mol (140 parts) of CH 3 Si (OCH 3) 2 Cl. The second introduction funnel was charged with 1.25 mol. (161.6 parts) di-N-butylamine While stirring at room temperature and under a nitrogen atmosphere,

  CH 3 Si (OCH 3) 2 C 1 was added rapidly to the reaction mixture.

  The di-N-butylamine was added dropwise over 2 hours to the rapidly stirred reaction mixture. A slight exotherm occurred which increased the temperature of the reaction mixture from 22 ° C to 35 ° C. Copious amounts of triethylamine hydrochloride formed. white solid during the reaction After stirring at room temperature for 15 hours, the solids are removed by vacuum filtration and the liquid volatiles are removed by rotary flash evaporation under reduced pressure. Vacuum filtration gives the expected product which is methyldimethoxy ( di-N-butylamino) silane having a boiling point of 600 C / 7 mm Hg and a purity of 88%

  as determined by gas chromatographic analysis.

  The aminosilane was then blended with a polymer filler and a tin catalyst under anhydrous conditions using a Semdit R mixer. The catalyst step was as follows: 85 parts of the same dimethylpolysiloxane polymer at 80.degree. Silanol end groups As in Example 1, 15 parts of the same treated fumed silica filler as in Example 1 and 2 to 5 parts of aminosilane were added. The whole was mixed during a first mixing step for 15 minutes. At room temperature, in a second step of mixing for 15 minutes at room temperature in a Semkit R mixer, 0.23 parts of dibutyltin diacetate and 1.0 part of a polymer were added to the first mixture. dimethylpolysiloxane having trimethylsiloxy end groups having a viscosity of 100 centipoise at 250 ° C. and a silanol group content of between 500 and

  1,500 parts per million The characteristics of hardening

  obtained from these compositions including, in some cases, the accelerated aging and the time of transition to the non-sticky state are given in Table 2 below.

TABLE 2

  Results with CH 3 Si (OCH 3) 2-N (butyl) 2 Rate in CH 3 Si (O CH 3) 2 N (butyl) 2 Time T V. stock (C) TPENC Durometer (min) (24 hours) ( parts) (days) O o

-

24

gelation in the tube

-

30

  gelling in the tube * Minimum rate of CH 3 Si (OCH 3) 2-N (butyl) 2 to obtain the

  storage stability and fast curing.

  T V = aging temperature

  TPENC = time of transition to non-sticky state.

2.0 2.7

4, O *

, 0

Claims (12)

  1 Process for producing a rubber composition   vulcanizable silane rubber at room temperature to a substantially acid-free component in which   a hardening accelerator is formed in situ immediately   after mixing the components, said method comprising mixing:   a) -100 parts by weight of a polydiorganosiloxane with   silanol end units consisting essentially of chemically combined units of the formula R sioR b) at least about 4 parts of a silane cleaner for the hydroxy-functional groups of the formula (R 2) b (R'O) 4 (ab ) If (X) c) 0 to 10 parts of a crosslinking silane of formula (R 2) (R'0) (4 _b) Si and d) an effective amount of a condensation catalyst, formulas in which R is selected from substituted or unsubstituted monovalent hydrocarbon radicals having 1 to 13 carbon atoms, R 1 is an aliphatic organic radical having 1 to 8 carbon atoms selected from alkyl, alkyl ether, ketoalkyl, and cyanoalkyl, or a substituted or unsubstituted monovalent hydrocarbon radical having 7 to 13 carbon atoms, X is a hydrolysable breakable amino group and a is an integer equal to 1 or 3, b is an integer equal to 0 or 1, the sum of a + b being equal to 1 or 3.   2 Process for the manufacture of an organometallic composition   polysiloxane vulcanizable at room temperature,   substantially free from acid, under the following conditions:   substantially anhydrous composition in which an accelerating   The curing agent is produced in situ immediately after the mixing of the components, said process using an effective amount of a condensation catalyst with an organopolysiloxane having silanol end groups and a polyalkoxysilane crosslinking agent, characterized by adding to 100 parts by weight of the organopolysiloxane with silanol end groups at least about 4 parts by weight of a polyalkoxysilane which   acts both as a cleaner for the hydroxyl groups   functional groups and as crosslinking agent, said organo-   polysiloxane having the formula (R 2) b (Ro) 4- (b + a) Si (X) in which R 1 is an aliphatic organic radical having 1 to 8 carbon atoms selected from the group consisting of radicals alkyl, alkyl ether, alkyl ester, ketoalkyl and cyanoalkyl, or an aralkyl radical having 7 to 13 carbon atoms, R 2 is a substituted or unsubstituted monovalent hydrocarbon radical having 1 to 13 carbon atoms, X is a hydrolyzable amino group breakable; a is an integer equal to 1 'or 3; b is an integer equal to 0 or 1; the sum of a + b being equal to 1 or 3; and then adding an effective amount of a condensation catalyst.   3 Process for producing a vulcanizing composition   one-component ambient temperature, and   acid-free composition which can be cured to a solid elastomeric state, and   curing accelerator being produced in situ immediately   after mixing the components, said method comprising stirring under substantially anhydrous conditions at a temperature between 0 ° C and 180 ° C, a room temperature vulcanizable material selected from: 1) a mixture comprising (a) 100 parts of a silanol end group polydiorganosiloxane formed essentially of chemically combined units of the formula RI-SiO 1   R (b) at least about 4 parts of a silane cleaner for the hydroxy-functional groups and having the formula (R 2) b (R 0) 4 (a + b) Si (X) a (c) 0 to 10 parts of a crosslinking silane of formula (R 2) b (Rlo) (4 -b) Si (d) an effective amount of a condensate catalyst 2) a mixture comprising (a) 100 parts of a polydiorganosiloxane with polyalkoxy terminal groups of formula (R 2) b R (R 2) b (R 10 lo) 3 - (b + e) (O (R 1) 3 - (b + e) O (OR 1) 3 (b + e) X R X   e (b) 0 to 10 parts of a crosslinking silane of formula (R 2) b (Ro) (4 _b) Si   (c) an effective amount of a condensate catalyst   wherein R is selected from substituted or unsubstituted monovalent hydrocarbon radicals having 1 to 13 carbon atoms, R is an aliphatic organic radical having 1 to 8 carbon atoms selected from alkyl, alkyl ether, and the like. , alkyl ester, ketoalkyl and cyanoalkyl, or an alkaryl radical having 7 to 13 carbon atoms, R 2 is a   substituted or unsubstituted monovalent hydrocarbon radical   killed with 1 to 13 carbon atoms, X is a hydrolyzable amino group breakable, a is an integer equal to 1 or 3, b is an integer equal to OO or 1, and the sum of a + b is equal to 1 or 3, e is an integer equal to O or 2, and the sum of b + e is 0 or 2, and N is an integer having a value between about and about 2,500, inclusive.   4 Process for producing a rubber composition   one-component, substantially acid-free, room-temperature vulcanizable silicone rubber, wherein a cure accelerator is produced in situ immediately after mixing the components, said method comprising mixing: (a) 100 parts of a polydiorganosiloxane with silanol end groups consisting essentially of chemically combined units of the formula R Sio-IR (b) at least about 4 parts of a siloxane cleaner for the hydroxy functional groups of the formula R 2 1 Y (RO) x Si O- (x) + y + w) A x   wherein R and R 2 are as defined above.   and a is a single amino radical of formula R 10 wherein R 1 and R 11, which are identical or different, are chosen from hydrogen and monovalent hydrocarbon radicals having from 1 to 8 carbon atoms, x is between 0.05 and and 2.50 is between 0.00 and 2.50; W is between 0.05 and 1.5 and the sum of x + + W is between 2.10 and 3.0 (c) 0 to 10 parts of a crosslinking silane of formula (R 2) b ( RO) (4-b) If Es   (d) an effective amount of a condensation catalyst   wherein R is selected from substituted or unsubstituted monovalent hydrocarbon radicals having from 1 to 13 carbon atoms, R 1 is an aliphatic organic radical having from 1 to 8 carbon atoms selected from alkyl, ether radicals, alkyl, alkyl ester, ketoalkyl and cyanoalkyl, or an aralkyl radical having 7 to 13 carbon atoms, R 2 is a   substituted or unsubstituted monovalent hydrocarbon radical   wherein the siloxane cleaner has the formula R 2 n (Rlo) m 4 i + n + o) 1   Wherein R 1 and R 2 are as previously defined and a is a single amino radical of formula 10 Ri   R 11   in which RO and R 1, which are identical or different, are chosen between hydrogen and monovalent hydrocarbon radicals having 1 to 8 carbon atoms, m is between 0.15 and 2.50, N is between 0, 1 and 1.9 and o is between 0.05 and 2.00, the sum of m + N + o being between 2.10 and 3.0.   6 Process for producing an organometallic composition   vulcanizable polysiloxane at substantial room temperature   acid-free, under substantially   partially anhydrous, in which a hardening accelerator   is produced in situ immediately after the mixing of the components and which uses an effective amount of a condensation catalyst with an organopolysiloxane silanol end groups and a polyalkoxysilane crosslinking agent, characterized in that it consists in adding to 100 parts in organopolysiloxane weight with silanol end groups at least about 4 parts by weight of a polyalkoxysilane which acts both as a cleaner for the functional hydroxy groups and as a crosslinking agent of the formula R 2 (R 1 o 0) SiO 4 ( x + y + w, wherein A is a single amino radical of formula 1 R 10 I he N R 1   in which R 1 and R 11, identical or different,   rents are selected from hydrogen and monovalent hydrocarbon radicals having from 1 to 8 carbon atoms, x is from 0.05 to 2.50; y is between 0.00 and 2.50; and W is between 0.05 and 1.5, the sum of x + y + W being between 2.10 and 3.0; R 1 is an aliphatic organic radical having 1 to 8 carbon atoms, selected from alkyl, alkyl ether, alkyl ester, ketoalkyl and cyanoalkyl radicals, or an aralkyl radical having 7 to 13 carbon atoms, R 2 is a substituted or unsubstituted monovalent hydrocarbon radical having 1 to 13 carbon atoms, then adding an effective amount of a condensation catalyst, whereby a room temperature vulcanizable organopolysiloxane composition having better stability.  7 Process according to claim 6, characterized in that the siloxane cleaner has the formula R 2   n (R 10) m Si (RO) wherein: R 1 and R 2 are as previously defined and A is a single amino radical of formula R 10 i R 11 I _ -N R 11   formulas in which R 10 and R 11, identical or different,   are chosen between hydrogen and hydrogen radicals.   monovalent carbon containing from 1 to 8 carbon atoms, m is between 0.15 and 2.50; N is between 0.1 and 1.9 o is between 0.05 and 2.0 and the sum of m + N + o is between 2.10 and 3.0.   8 Process for producing a vulcanizing composition   at room temperature to a substantially acid-free component, capable of solid state elastomer curing, wherein a cure accelerator is produced in situ immediately after   mixing the components, said method comprising agitating.   under substantially anhydrous conditions at a temperature between OC and 180 C a room temperature vulcanizable material selected from: 1) a mixture comprising (a) 100 parts of a silanol terminated polydiorganosiloxane formed essentially of chemically combined units of formula -5 R If O- I   R (b) a stabilizing amount of a siloxane cleaner for the hydroxy functional groups of the formula R 2 yi I (R 0) xi 4 (x + Y + w) wherein R, R and R are such that defined below, and A is a single amino radical of formula R -N R 11   o R 10 and R 1, identical or different, are chosen   between hydrogen and monohydrocarbon radicals   valents having from 1 to 8 carbon atoms, x is from 0.05 to 2.50; y is between 0.00 and 2.50; W is between 0.05 and 1.5, and the sum of x + + W is between 2.10 and 3.0 (c) 0 to 10 parts of a crosslinking silane of formula R 2 b (Rlo) (4-b) If   (d) an effective amount of a condensation catalyst   tion; and 2) a mixture comprising (a) 100 parts of a polydiorganosiloxane having polyalkoxy terminal O groups of the formula (R 2) R (R 2)   (R 0) 3- (b + e) If O Si O i (-R ') (b) Riit i (01 _ (b + e) X R X   e N) 0 to 10 parts of a crosslinking silane of formula 2 O (R) b (R'O) (4-b) Si and 4) an effective amount of a condensation catalyst, wherein R is selected from substituted or unsubstituted monovalent hydrocarbon radicals having from 1 to 13 carbon atoms, R is an aliphatic organic radical having 1 to 8 carbon atoms selected from the group consisting of alkyl, alkyl ether, alkyl, ketoalkyl and cyanoalkyl, or an alkaryl radical having 7 to 13 carbon atoms, R 2 is a monovalent hydrocarbon radical, substituted or unsubstituted, having 1 to 13 carbon atoms, X is a hydrolyzable amino group breakable; b is an integer equal to 0 or 1; e is an integer equal to 0 or 2, the sum of b + e being equal to 0 or 2, and N is an integer having a   value between about 50 and 2500, inclusive.   9) Process according to claim 8, characterized in that the cleaning silane has the formula R 2 (R'm Si O 4- (m + n + G) 2   Wherein R 1 and R 2 are as previously defined, and A is a single amino radical of formula R 10 _ N_ R   formulas in which R 10 and R 11, identical or different,   are chosen from hydrogen and radicals.   monovalent hydrocarbon compounds having 1 to 8 carbon atoms m is between 0.15 and 2.50; N is from 0.1 to 1.0; and o is between 0.05 and 2.0, the sum m + n   + o being between 2.10 and 3.0.   Method according to any one of the claims   1, 2, 4 and 6, characterized in that the crosslinking agent is methyltrimethoxysilane.   Process according to any one of the claims   1, 2, 4, 6 and 10, characterized in that R, R 1 and R 2 are methyl groups.   Process according to any one of the claims   1, 2, 4, 6, 10 and 11, characterized in that the catalyst of   Condensation is a compound of tin.   Process according to any one of the claims   1, 2, 4, 6, 10 to 12, characterized in that the condensation catalyst is selected from dibutyltin dilaurate and dibutyltin diacetate.   Process according to any one of the claims   1, 2, 4, 6, 10 to 13, characterized in that the silane   cleaner is methyldimethoxy (di-N-hexylamino) silane.   Process according to any one of the claims   1, 2, 4, 6, 10 to 13, characterized in that the silane   cleaner is methyldimethoxy (di-N-methylamino) silane.   Process according to any one of the claims   1, 2, 4, 6, 10 to 13, characterized in that the silane   cleaner is methyldimethoxyisopropylaminosilane.