DESC:FIELD OF INVENTION

The present invention provides for a storage stable and flowable master-batch composition and a step-wise process of making the master-batch composition that comprising the step of, admixing one or more ingredient selected from a part of a first reinforcing filler, a part of a non-reactive oil, and mixtures thereof, to obtain a mixed product. Then admixing step-wise one or more ingredient selected from a part of a pretreatment agent and a part of a first protic substance to the mixed product to form a partially reacted product. Then continuing admixing further parts of one or more ingredients until the ingredients are used-up to form a reacted product, andremoving volatiles from the reacted product to obtain the master-batch and further heating the master-batch at a temperature between 400C and 1500C to remove ammonia and the protic substance, and optionally diluting the master-batch with a diluent preferably the non-reactive oil. This master-batch is used as a base material for various applications, including but not limited toRTV-2 composition where in the master-batch a silicone base is addedto form the silicone compound which is the first component of a two-component room temperature curable silicone compositions. The master-batch is further emulsified to obtain an emulsion composition that is used as a antifoam application and is also suitable for varied applications including a room temperature curable crosslinkable RTV-2 silicone composition.

BACKGROUND

Two-component room temperature curablesilicone compositions is well known in the prior art for various applications like mould making for reproducing. RTV silicone rubber reproduces fine details and is helpful to make moulds for a variety of industrial and art related applications including prototypes, sculpture, architectural elements and furniture.

US6288143B1 describes a method for preparing the first component of a two-component room temperature-vulcanizable (RTV) silicone composition comprises (a) preparing a filler/oil master-batch by (i) adding an unreactive silicone oil and untreated, aggregated filler particles to a mixer; (ii) adding a filler treating agent such as an organosilane, a polyorganosilane or a silazane to the unreactive silicone oil/filler mixture; and (iii) mixing the unreactive silicone oil/filler mixture and treating agent under conditions sufficient to breakdown the aggregated filler particles to an average size of less than about 300 nm for a time of less than about 24 hours to form the filler/oil master-batch; and (b) adding said filler/oil master-batch to a reactive silicone oil.

In US8907006 B1 liquid silicone rubber base polymer compositions having improved color are prepared by reaction of fumed silica reinforcing filler with a silazane, and without drying the silazane-treated filler, an aliphatically unsaturated silicone is added, heated to above 80° C., and then further aliphatically unsaturated silicone is added. The compositions have improved whiteness and color reproducibility.

In all the prior arts, hexamethyldisilazane is used in forming the masterbatch by loading the total silazane all at one time of the reaction. But, as it is known that hexamethyldisilazane is a highly flammable material having a flash point of 11 oC, the prior art process as described is highly dangerous and unsafe process.

Also, when the filler is treated in one step the hydroxyl group of the filler do not react properly and if filler is not treated properly the filler become thixotropic due to reaction of reactive polymer with the hydroxyl group of the silica.

Moreover, in such prior art process, huge amount of ammonia gas gets liberated at a much higher rate than desired. High concentration of ammonia may cause burn, poisoning or other health hazards.

So, it is therefore a need to develop a master-batch composition and an advanced process to manufacture the master-batch composition for various application such as but not limited to a two-component room temperature vulcanizable composition, which does not have such hazards and disadvantages and is cost effective and less time consuming to manufacture or as an antifoam composition.

OBJECTS OF THE INVENTION
It is thus the primary object of the present invention to provide for a masterbatch composition involving pretreated reinforcing filler having blocked surface hydroxyl groups to avoid its thixotropic behavior when present in combination with a reactive polymer.

It is thus another object of the present invention to provide for a facile and stepwise process for the manufacture of said masterbatch composition involving steps to effectively pretreat the fillers with pretreatment agent in a manner to avoid higher rates of generation of toxic gas to simultaneously facilitate effective reaction of the surface hydroxyl groups of the filler.

It is yet another object of the present invention to provide for storage stable and flowable masterbatch composition that would be storage stable having desired viscosity based on its non-reactivity with any reactive polymer when included in the composition.

It is still another object of the present invention to provide for said masterbatch composition that would favour ease of pretreated filler incorporation in reactive silicone base polymer and the desired homogeneity.

It is yet another object of the present invention to provide for said masterbatch composition suitable for end use and application as an emulsion composition preferably for antifoam applications that would also be suitable for varied applications including a room temperature curable crosslinkable RTV-2 silicone composition.

SUMMARY OF THE INVENTION

Thus according to the basic aspect of the present invention there is provided a storage stable and flowable master-batch composition comprising:
a pretreated reinforcing filler having blocked surface hydroxyl groups with surface hydroxyl content less than 1000 parts per million of the composition.

In one of the preferred embodiments, the surface hydroxyl content is less than 500 parts per million.

In one of the other preferred embodiments, the surface hydroxyl is completely blocked or reacted.

Preferably said storage stable and flowable master-batch composition comprises a diluent.

More preferably said storage stable and flowable master-batch composition comprises a reactive organopolysiloxane base.

According to another preferred aspect of the present invention said storage stable and flowable master-batch composition comprises an extender filler.

Preferably in said storage stable and flowable master-batch composition wherein the reactive organopolysiloxane comprising atleast a functional group selected from hydroxyl, alkoxy, vinyl and mixtures thereof.

According to yet another preferred aspect of the present invention in said storage stable and flowable master-batch composition wherein the reinforcing filler is selected from pyrogenic silica, precipitated silica, silicon-aluminum mixed oxides, pyrogenic titanium dioxide or its mixtures thereof.

According to another aspect of the present invention there is provided an emulsion composition comprising said storage stable and flowable master-batch composition.

According to another aspect of the present invention a process of preparing a storage stable and flowable master-batch composition is provided comprising step-wise manufacture of pretreated reinforcing filler including:
admixing one or more ingredient selected from a part of a first reinforcing filler, a part of a non-reactive oil, and mixtures thereof, to obtain a mixed product;
admixing step-wise selectively a part of a pretreatment agent and a part of a first protic substance to the mixed product to form a partially reacted product;
continuing admixing further parts of one or more ingredients until the ingredients are used-up to form a reacted product, and
removing volatiles from the reacted product to obtain the master-batch.

Preferably in said process removing volatiles further comprises the steps of:
heating the master-batch at a temperature between 40oC and 150oC to remove volatiles selected from ammonia, the protic substance and mixtures thereof.

More preferably said process further comprises the step of:
optionally diluting the master-batch with a diluent to obtain a modified master-batch.

According to another preferred aspect of the present invention said process further comprises the step of adding a reactive organopolysiloxane base to the master-batch or the modified master-batch to form a liquid silicone rubber base polymer composition.

Preferably said process further comprises the step of adding an extender filler.

More preferably said reactive organopolysiloxane comprises atleast a functional group selected from hydroxyl, alkoxy, vinyl and mixtures thereof.

According to another preferred aspect of the present invention in said process said reinforcing filler is selected from pyrogenic silica, precipitated silica, silicon-aluminum mixed oxides, pyrogenic titanium dioxide or its mixtures thereof.

Preferably in said process said pretreatment agent is selected from an organosilane, an organosilazanes, an organosiloxanes or its mixtures thereof.

According to another preferred aspect of the present invention said process further comprises the step of adding a hardner composition post addition of reactive organopolysiloxane base to the master-batch or the modified master-batch to form crosslinkable RTV-2 silicone composition.

According to another aspect of the present invention a crosslinkable RTV-2 silicone composition, is provided comprising:
storage stable and flowable master-batch composition having a pretreated reinforcing filler
having blocked surface hydroxyl groups with surface hydroxyl content less than 0.01 parts per million of the masterbatch composition.

Preferably said crosslinkable RTV-2 silicone comprises liquid silicone rubber base polymer and a hardner composition.

More preferably said crosslinkable RTV-2 silicone composition is obtained by said process of preparing the masterbatch composition followed by adding a hardner composition post addition of reactive organopolysiloxane base to the master-batch or the modified master-batch to form crosslinkable RTV-2 silicone composition.

Preferably in said crosslinkable RTV-2 silicone composition the hardener composition comprising atleast one crosslinking agent and atleast one catalyst.

More preferably said crosslinked RTV-2 silicone comprises
cross linked liquid silicone rubber base polymer with hardener composition including
storage stable and flowable master-batch composition having a pretreated reinforcing filler
having blocked surface hydroxyl groups with surface hydroxyl content less than 1000 parts per million of the masterbatch composition .

According to another aspect of the present invention there is provided an emulsion composition comprising said master batch or modified master batch.

DETAILED DESCRIPTION OF THE INVENTION
As described hereinbefore the present invention provides for a storage stable and flowable master-batch composition and a step-wise process of making the master-batch composition that comprising the step of, admixing one or more ingredient selected from a part of a first reinforcing filler, a part of a non-reactive oil, and mixtures thereof, to obtain a mixed product. Then admixing step-wise one or more ingredient selected from a part of a pretreatment agent and a part of a first protic substance to the mixed product to form a partially reacted product. Then continuing admixing further parts of one or more ingredients until the ingredients are used-up to form a reacted product, andremoving volatiles from the reacted product to obtain the master-batch. Heating the master-batch at a temperature between 400C and 1500C to remove ammonia and the protic substance, and optionally diluting the master-batch with a diluent preferably the non-reactive oil. This master-batch is used as a base material for various applications, including but not limited toRTV-2 composition where in the master-batch a silicone base is added to form the silicone compound which is the first component of a two-componentroom temperature curablesilicone compositions. The master-batch is further emulsified to obtain an emulsion composition that is used as an antifoam application.

The filler react with the pretreatment agent (e.g. silazane) for improving reinforcing behavior of filler in rubber compound and carry out treatment with a lower concentration of silazane and thus reduce the chances of silazane flammability.
When the filler is treated step-wise properly with silazane the compound becomes more flowable which is measured by Mixed Viscosity (is the mix of base and catalyst mixture) in cps @ 25ºC & 50%RH Method: ISO 3219, which is an important factor for the RTV compound.
The present invention thus provides for a master-batch composition and a step-wise process of making the master-batch composition comprising a step-wise manufacturing of a pretreated reinforcing filler that comprising the step of:
admixing one or more ingredient selected from a part of a first reinforcing filler, a part of a non-reactive oil, and mixtures thereof, to obtain a mixed product, then admixing step-wise one or more ingredient selected from a part of a pretreatment agent and a part of a first protic substance to the mixed product to form a partially reacted product, continuing admixing further parts of one or more ingredientsuntil the ingredients are used-up to form a reacted product, and
removing volatiles from the reacted product to obtain a master-batch.
The step-wise process, wherein removing volatiles further comprising the step of: heating the master-batch at a temperature between 40oC and 150oC to remove volatiles selected from ammonia, the protic substance and mixtures thereof.

The process further comprising the step of optionally diluting the master-batch with a diluent to obtain a modified master-batch.

The step of adding a reactive organopolysiloxane base to the master-batch or the modified master-batch to form the liquid silicone rubber base polymer composition. The step-wise process, further comprising the step of adding an extender filler.
The reactive organopolysiloxane comprising atleast a functional group selected from hydroxyl, alkoxy, vinyl and mixtures thereof. The reinforcing filler is selected from pyrogenic silica, precipitated silica, silicon-aluminum mixed oxides, pyrogenic titanium dioxide or its mixtures thereof. The pretreatment agent is selected from an organosilane, an organosilazanes, an organosiloxanes or its mixtures thereof.

A crosslinkable RTV-2 silicone composition, comprising a silicone rubber base polymer obtained by the process.

A crosslinkable RTV-2 silicone composition, further comprising a hardener composition.
A crosslinkable RTV-2 silicone composition, wherein the hardener composition comprising atleast one crosslinking agent and atleast one catalyst.

The pretreated reinforcing filler, having blocked surface hydroxyl groups with surface hydroxyl content less than 1000 parts per million of the composition. In one of the preferred embodiments, the surface hydroxyl content less than 500 parts per million. In one of the other preferred embodiments, the surface hydroxyl is completely blocked or reacted.

Examples of the reinforcing filler having a specific surface area (BET) of at least 40 m2/g are pyrogenic silica, precipitated silica, silicon-aluminum mixed oxides and pyrogenic titanium dioxide. Preference is given to pyrogenic and precipitated silicas having a specific surface area (BET) of 50-400 m2/g, particularly preferably 90-300 m2/g. The filler mentioned can have been pretreated, for example with organosilanes, organosilazanes or organosiloxanes.

The fumed silica useful in the invention include fumed silicas having a specific surface area, measured by the BET method, of at least 50 m2/g, and more preferably 100 m2/g to 300 m2/g.

The compositions may also contain fillers, e.g. basic fillers such as ZnCO3, ZnO, CaCO3, CaO, MgCO3 and MgO, which also act as curing accelerators, and extender fillers, such as diatomaceous earth, quartz, glass fibers, silica aerogels and fume silica, pigments flavorings and essential oils.

In one of the embodiments, such fumed silicas are commercially available. Preference is given to pyrogenic and precipitated silicas having a specific surface area (BET) of 50-400 m2/g, particularly preferably 90-300 m2/g. Also useful, but less preferred, are partially hydrophobicizedsilicas which have been hydrophobicized only partially and then dried. Such silica still contain a significant amount of unreacted silanol groups, e.g. more than 10% (mol %) of the original surface silanol group content as determined by the 29Si NMR, more preferably more than 20%, yet more preferably more than 30%, and may be in one embodiment, more than 40%, 50%, 60%, 70%, 80%, and 90%.

The pretreatment agent is selected from an organosilane, an organosilazanes,an organosiloxanes or its mixtures thereof. The pretreatment agent (e.g. silazane) used in the admixing step may be any silazane useful for making the silica compatible with the non-reactive oil by reacting with the active group of silica, preferably a disilazane. The most preferred disilazanes are hexamethyldisilazane (“HMN”) and divinyltetramethyldisilazane (“VMN”). Both of these are commercially available products. Less preferred disilazanes, generally due to cost considerations, are disilazanes substituted with other substituents, preferably C2-18 alkyl groups, most preferably C2-6 alkyl groups, i.e. ethyl groups; aryl groups such as phenyl and napthyl, arylalkyl groups such as benzyl and phenylethyl; alkaryl groups such as tolyl and xylyl; cycloalkyl groups, and the like. These groups may optionally be substituted, for example, by chloro, fluoro, cyano, alkoxy, and similar substituents.

The disilazane may also include Si-bonded unsaturated groups such as vinyl, alkyl, propenyl, isopropenyl, 5-hexenyl (meth)acryloxy, and the like. Since effective removal of active groups of silica does not require unusual or exotic substituents, substituents selected from C2-6 alkenyl and C1-6 alkyl are preferred, with methyl, ethyl, vinyl and allyl groups being more preferred, and with methyl and vinyl being most preferred. In addition to disilazanes, polysilazanes such as hexamethylcyclotrisilazane and octamethylcyclotetrasilazane are also useful, as well as other cyclic silazanes which act by a ring opening reaction with silanol groups. The disilazanes and polysilazanes described above include all organic disilazanes useful for silica, and are referred to hereafter as “organic disilazanes,” or more simply, “silazanes”.

The silazanes are used in an amount effective to achieve the desired blocking of the reactive groups (e.g. hydroxyl) of the silica. This latter can be determined and can be adjudged by the ease with which the silica can be incorporated into the silicone base polymer, and the homogeneity of the resultant base polymer composition. In general, the effective amount of silazane will be proportional to the surface silanol content, e.g. in nmol/g or µmol/g, with silicashaving more active group requiring more silazane and silicashaving less active group requiring less silazane. On a weight percent basis, the silazane is generally present in an amount, based on silica, of 1 to 40% by weight, preferably 5 to 40% by weight, more preferably 10 to 40% by weight, and most preferably 20% to about 30% by weight. The amount is preferably such that the partially reacted silica contains from 2 to 20 weight percent, preferably 5 to 10 weight percent of dimethylsiloxy units or 3 to 20 weight percent, preferably 6 to 12 weight percent of trimethylsiloxy units, and when a mixture of dimethylsiloxy and trimethylsiloxy groups, or other silazane-derived groups are present, these amounts are adjusted accordingly. The weight percentages are based on the total weight of the silica.

Water or another protic substance, preferably water, must be present during the admixing step of the process. Water may be present in adsorbed or absorbed form on the silica, or may be added separately. Deionized water or reverse osmosis-produced water is preferably used. Water should preferably be present in sufficient amount to react with substantially all of the silazane added. This amount is thus at least partially dependent upon the amount of silazane added, which is also dependent upon the surface silanol content of the silica. Suitable amounts of water can easily be determined, for example by monitoring unreacted silazane, by monitoring the amount of ammonia liberated.

In the admixing stage reaction between the silazane and silica, in the presence of a protic substance, preferably water, is generally effected at a temperature of from -20° C. to 100° C., preferably 0° C. to 80° C., more preferably 10° C. to 60° C., and most preferably at a temperature established by mixing silica, silazane and water in a stirred reactor at room temperature, without the use of external heat or cooling, which is preferred. Upon mixing, an exotherm will be produced as the silazane reacts. This exotherm may cause the temperature to rise, for example, to a temperature of from 40° C. to 70° C., preferably 50-60° C. The final temperature reached is not critical so long as coloration is avoided, but should be sufficient to react a substantial portion of the silazane at this stage, to form a master-batch. Ammonia will be generated at this stage, and is preferably removed according to best practice.

One of the applications of the master-batch prepared is a cross-linkable RTV-2 composition. The next stage is mixing of the silicone base polymer to the master-batch and few of the ingredients like TiO2 and moisture adjustor to form the first component of the two-component room temperature curable silicone composition. In one of the embodiment, a silicone base polymer is at least one silicone base polymer selected from a silicone OH polymer (hydroxyl-terminated dimethylpolysiloxane fluid (viscosity of 12000 cps at 250C available from Wacker, (OH 12 K silicone polymer)) or a silicone polymer having at least two aliphatically unsaturated groups, these silicones being organopolysiloxanes containing at least three silicon atoms. Where low modulus products are desired, the average content of aliphatically unsaturated groups may be less than two. This may be achieved, for example, by incorporating silicone polymers bearing a single unsaturated group in conjunction with silicone polymers containing two or more unsaturated groups.

The second component is usually a hardener composition, where the hardener composition comprising atleast one crosslinking agent and atleast one catalyst. The catalyst that catalysesthe condensation or addition reaction of the silicone base polymer (present in the first component) to impart desired mechanical properties of the room temperature vulcanized rubber and the flow property and the cure properties of the mix of the first and second component of the two component room temperature curable silicone composition.

After mixing the first and the second component the mixture is usually poured in a die and left over time to get cured to form the room temperature vulcanized rubber. The pouring of the mixed fluid is governed by the mixed viscosity in cps at 250C.

Usually the 100 parts of firstcomponent of the two-component liquid silicone rubber base polymer is mixed in an amount of 1 to 10 parts preferably 5 parts of a Tin based catalyst which is the second component to get the room temperature vulcanized rubber.

In another embodiment, the master-batch composition is used as an anti-foam composition. The master-batch or the diluted master-batch is optionally diluted with a diluent preferably the non-reactive oil and emulsified with one or more non-ionic emulsifier and its mixtures to foam an emulsified composition. Such emulsion of the present invention is having superior antifoam action.

EXAMPLES
1) Inventive Example:
In the inventive example the non-reactive oil used is WACKER® AK 350 SILICONE FLUID (AK 350) is a linear, non-reactive polydimethylsiloxane with a viscosity of approx. 350 mm²/s.
Silazane used is a WACKER® SILAZAN HMN (Silazen HMN) is a colorless liquid with strong odour.
ULTRASIL® VN 3 GR (VN3 filler) as a precipitated silica is used as a reinforcing filler.
Water used is a reverse osmosis treated demineralized water.
The In situ filler treatment is done in sigma mixture.

The inventive step-wise process which is followed is disclosed in Table 1:
Table 1: Inventive step-wise process followed for Recipe of table 1:
Stage 1 (In stage 1 the inventive method step is followed in Sigma mixture to form the Master-batch)
RM Qnty (kg) % Process
AK 350 1.39 19.02 Powder added in 5 steps. Took AK350 fluid in the Sigma & added 368 gm VN3 filler. Powder mixed with fluid within 15 min. Added 28 gm Silazen HMN +10 gm water & mixed for 60 min (need to ensure no NH3 generated from the mixture at the end of the reaction).
VN3 filler 1.84 25.18 Again, added 368 gm VN3 filler& it took 120 minutes for mixing. Added 28 gm Silazen HMN + 10 gm water & mixed for 120 min (need to ensure no NH3 generated from the mixture at the end of the reaction).
Silazen HMN 0.14 1.92 Followed the above sequence for another 3 times to dissolve & treat the powder
Water 0.05 0.68 Total treatment time =17 hr 15 min
After ammonia vapor removal, heat the compound under mixing to 130°C. ( 1hr)
When the pH of the mass become neutral, add the below ingredients.
AK 350 0.692 9.47 Mixing for 1 hr, Viscosity ~ 4 lac cps @ 25°C by Rheometer–The compound obtained is Not flowable
AK 350 0.692 9.47 Mixing for 1 hr, Viscosity ~ 75 k cps @ 25°C by Rheometer–The compound obtained is Flowable
Total 4.804 65.75 Total time in Sigma ~ 20 hr

The master-batch as formed in stage 1, it is found that by 29Si NMR the hydroxyl content of the master-batch as formed in stage 1 is less than 500 parts per million, which suggest that the surface hydroxyl group of the reinforcing filler is reacted/ blocked.

Application I. Condensation system for mold making application:
Stage 2 (a): In stage 2 the Master-batch of stage 1 is further with a silicone base polymer to form the first component of the condensation system in a Dispenser
RM Qnty (kg) % Process
Master batch of Sigma mixture 4.804 65.75
Titanium di oxide pigment 0.13 1.78 Mix for 10 min @ 5000 - 6000 rpm
OH 12 k 2.374 32.48 Mix for 10 min @ 5000 - 6000 rpm ( Final viscosity, 27 K)
Total 7.308 100 Total time in Disperser = 30 min

Stage 2 (b): In stage 2 the Master-batch of stage 1 is further with a silicone base polymer to form the first component of the condensation system in a Dispenser
RM Quantity (kg) % Process
Master batch of Sigma mixture 4.8 58.5
Titanium di oxide pigment 0.106 1.3 Loaded base & Quartz Batch. Then Loaded AK 100 and started mixing
OH 20 k 1.94 23.6 Loaded OH 20 K & mixed
Quartz, 5 micron particle 1.1 13.4 Added one by one & mixed
AK 100 0.24 2.9
Moisture adjuster emulsion 0.025 0.3
Total 8.2 100 Total time in Disperser = 140 min

2) Comparative Example
Table 2: Comparative process: the following ingredients are added in the serial order and in the specific amount as described in the table.
Stage 1 (comparative): (In stage 1 the comparativemethod of one step is followed in Sigma mixture to form the Master batch)
Sl. No. Reagents Amount (kg) Amount (%)
1 AK-350 1.5 34.9 in total Powder added in 1 step. Took AK350 fluid in the Sigma & added 1.99kg VN3 filler. Powder mixed with fluid within 15 min. Added 140 gm Silazen HMN +265 gm water slowly & mixed until NH3 stops getting generated from the mixture at the end of the reaction). Then AK 350 is further added slowly and mixed to adjust the viscosity
2 VN3 Filler 1.99 29.5
3 Silazane HMN 0.14 2
4 Water 0.265 3.7
AK350 0.848
TOTAL 2.283 100

To the base obtained from Table 2 the following silicone base and other ingredients are added to get the one componentof the two-component room temperature curablesilicone compositions according to the following stage 2.
Stage 2 (comparative) condensation: To the base formed in the comparative product of Stage 1 of Table 2 to form the silicone compound which is the comparative first component
Sl no RM Qnty (gms) %
1 Base of Stage 1 (comparative) condensation 784.4 65.4
2 OH 12K silicone polymer 386.9 32.2
3 TiO2 21.2 1.8
5 Moisture adjuster emulsion 7.6 0.6
1200 100.0

3) Mixing first and second component to obtain room temperature vulcanized rubber and the mechanical properties
To the following 100 parts of one part of the two part liquid silicone rubber base polymer of stage 2 (a) and (b) of Table 1, 1 to 10 parts preferably 5 parts of a Tin based catalyst; Wacker Catalyst T 37 is added to get the RTV condensation rubber 1 (a) and (b) respectively. The properties are depicted in Table 3.
To the following 100 parts of one part of the two part liquid silicone rubber base polymer of Stage 2 (comparative) condensation of Table 2, 1 to 10 parts preferably 5 parts of a Tin based catalyst; Wacker Catalyst T 37 is added to get the RTV rubber 2.

Table 3: Inventive RTV rubber 1(a)and 1(b) (condensation curing system) properties:
Parameters VALUES
MECHANICAL RTV rubber 1 (a) RTV rubber 1 (b)
Hardness (Shore A)
Method: DIN 53 505 20 20
Elongation (%)
Method: DIN 53 504 S 1 500 450
Tensile (N/mm2)
Method: DIN 53 504 S 1 3.5 3.5
Tear (N/mm) ASTM D 624 B
Method: ASTM D 624 B 25 20
Linear Shrinkage (%) < 0.4 < 0.4
Sp. gravity @ 25ºC in water
Method: DIN EN ISO 1183-1 A 1.16 1.16
FLOW PROPERTY
Mixed Viscosity ISO 3219 cps @ 25ºC & 50%RH
Method: ISO 3219 15,000 15000
CURE PROPERTY
Working time / Pot life of catalyzed
mixture at 25ºC& 50% RH (min)
Method: ISO 3219 90-120 90-120
Total curing time (hr) 24 24

Table 4: Comparative RTV rubber 2 (condensation system) properties:
Parameters VALUES
MECHANICAL
Hardness (SA); Method: DIN 53 505 23
Elongation (%); Method: DIN 53 504 S 1 356
Tensile (N/mm2); Method: DIN 53 504 S 1 2
Tear (N/mm); Method: ASTM D 624 B 14.4
Linear Shrinkage (%) < 0.51
Sp. gravity @ 25ºC in water; Method: DIN EN ISO 1183-1 A 1.16
FLOW PROPERTY
Mixed Viscosity in cps @ 25ºC & 50%RH ; Method: ISO 3219 23000
CURE PROPERTY
Working time / Pot life of catalyzed
mixture at 25ºC& 50% RH (min)
Method: ISO 3219 60
Total curing time (hr.) 36

From the above Table 3 and Table 4, we found that the final property (mechanical properties, flow properties and cure properties) of the silicone rubber is much higher in case of the RTV rubber 1 (a) and (b) made of the inventive process as in Table 1.

Application II. Addition system for electrical potting application:
Stage 2 (inventive) addition: In stage 2 the Master-batch of stage 1 of Table 1, is further with a silicone base polymer (vinyl polymer) to form the first component of the addition system in a Dispenser
SL no RM Quantity (Kg) %
1 41.6 % master batch of Sigma mixture from stage 1 of Table 1 1.975 19.75
2 Quartz, 5 micron 4.57 45.7
3 Polydimethylsiloxane with terminal vinyl group (Vinyl polymer) with 200 m.Pa.s viscosity at 25 oC 3.38 33.80
4 Titanium di Oxide 0.07 0.7
5 Platinumcatalyst 0.0026 0.026
9.9976

Comparative Example of addition system:
SL no RM Qnty %
1 41.6 % base formed in the comparative product of Stage 1 (Comparative) of Table 2 1.975 19.75
2 Quartz, 5 micron 4.57 45.7
3 Polydimethylsiloxane with terminal vinyl group (Vinyl polymer) with 200 m.Pa.s viscosity at 25 oC 3.38 33.80
4 Titanium di Oxide 0.07 0.7
5 Platinum catalyst 0.0026 0.026
9.9976

To the following 100 parts of one part of the two part liquid silicone rubber base polymer of Stage 2 (inventive) addition, and 1 to 10 parts preferably 4 parts of a cross linker Si-H catalyst to get the RTV addition curing rubber 1(c).
To the following 100 parts of one part of the two part liquid silicone rubber base polymer of comparative example of addition system, and 1 to 10 parts preferably 4 parts of a cross linker Si-H catalyst to get the RTV addition curing rubber 3.

Table 5: Inventive RTV rubber 1(c) (addition curing) properties:
Parameters Values
Hardness, Shore A; ISO 868 36
Tensile Strength (N/mm2); DIN 53 504 S 1 1.5
Elongation at break (%); DIN 53 504 S 1 190
Tear resistance (N/mm); ASTM D 624 B 1.5
Dielectric Strength ( 2 mm Specimen) (KV/mm)
IEC 60243 17
Volume Resistivity (O cm); IEC 60093 1012

Table 6:Comparative RTV rubber 3 (addition system) properties
Parameters Values
Hardness, Shore A; ISO 868 25
Tensile Strength (N/mm2); DIN 53 504 S 1 1.0
Elongation at break (%); DIN 53 504 S 1 140
Tear resistance (N/mm); ASTM D 624 B 1.2
Dielectric Strength ( 2 mm Specimen) (KV/mm)
IEC 60243 11
Volume Resistivity (O cm); IEC 60093 1010
From the above Table 5 and Table 6, we found that the final property (mechanical properties, electrical properties, flow properties and cure properties) of the silicone rubber is much higher in case of the RTV rubber 1 made of the inventive process as in Table 1.
Also, the material that is formed in Stage 2, Table 2 of the comparative example, on storage becomes thixotropic or the flow property degrades on storage. Whereas, the first component produced by the inventive process obtained at step 2 of the table 1 and stage 2 (inventive) addition systems, remains flowable and do not looses flowability on storage.
Application III. Antifoam emulsion by Master batch:
Preparation of the Emulsion:
Table 7: Emulsion composition for antifoam application (inventive and competitive):

Ingredient Antifoam of the invention,
Weight of the components (gram) Antifoam of the competitive example,
Weight of the components (gram)
Master batch of Sigma mixture of stage 1 of Table 1 (Inventive) 186 0
Master batch of stage 1 (competitive) of Table 2 0 186
Ak 350 824 824
PolyoxyethyleneOleylCetyl Ether 65 65
Mixture of fatty alcohol 35 35
Xanthum gum 4 4
Demineralized water 844 844
Kathon CG 2 2
Triethyl amine 1 1
1961 1961

Mixing the above inventive antifoam composition, emulsion is formedhaving visual appearance of white liquid, Nonvolatile substance (at 105 °Cfor 3 hrs.) is from 55 – 65% having a pH at 25°C 7 – 9. The emulsion is Water miscibility Dispersible and emulsifier is a non-ionic type.

Evaluation of Antifoam Efficiency:
Preparation: Prepare 1 lit of surfactant solution.Add 0.01% and 0.02 volume% amount of antifoam respectively.
Test Protocol:
The test solution is poured into a jacketed glass cylinder.Temperature is set to 60ºC.
Air flow is passed through a sintered glass bubbler (6lit/min).Foam is generated by the air flow.
Time to reach the 2 lit mark is noted.More the time required to reach 2 lit mark is better efficiency of the antifoam.
Time Taken to reach 2 Litres mark (in minutes)
Inventive antifoam Competitive antifoam
0.01 % Dose 34 29
0.02% Dose 49 42

Thus we find that the antifoaming action is superior in case of the antifoam made of the master-batch of the inventive process and composition.

While embodiments of the invention have been illustrated and described, it is not intended that these embodiments illustrate and describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention.
,CLAIMS:We Claim:
1. A storage stable and flowable master-batch composition comprising:
a pretreated reinforcing filler having blocked surface hydroxyl groups with surface hydroxyl content less than 1000 parts per million of the composition.

2. The storage stable and flowable master-batch composition as claimed in claim 1 comprising diluents and wherein said pretreated reinforcing filler having blocked surface hydroxyl groups with surface hydroxyl content being less than 1000 parts per million of the composition preferably the surface hydroxyl content being less than 500 parts per million and more preferably the surface hydroxyl is completely blocked or reacted.

3. The storage stable and flowablemaster-batch composition as claimed in anyone of claims 1 or 2 comprising a reactive organopolysiloxane base.

4. The storage stable and flowable master-batch composition as claimed in anyone of claims 1-3 comprising an extender filler.

5. The storage stable and flowable master-batch composition as claimed in claim 3, wherein the reactive organopolysiloxane comprising atleast a functional group selected from hydroxyl, alkoxy, vinyl and mixtures thereof.

6. The storage stable and flowable master-batch composition as claimed in anyone of claims 1 or 5, wherein the reinforcing filler is selected from pyrogenic silica, precipitated silica, silicon-aluminum mixed oxides, pyrogenic titanium dioxide or its mixtures thereof.

7. An emulsion composition comprising storage stable and flowable master-batch composition as claimed in anyone of claims 1 or 2.

8. A process of preparing a storage stable and flowable master-batch composition as claimed in claim 1 comprising step-wise manufacture of pretreated reinforcing filler including:

admixing one or more ingredient selected from a part of a first reinforcing filler,a part of a non-reactive oil, and mixtures thereof, to obtain a mixed product;
admixing step-wise selectively a part of a pretreatment agent and a part of a first protic substance to the mixed product to form a partially reacted product;
continuing admixing further parts of one or more ingredientsuntil the ingredients are used-up to form a reacted product,and
removing volatiles from the reacted product to obtain the master-batch.

9. The process as claimed in claim 8, wherein removing volatiles further comprising the step of:
heating the master-batch at a temperature between 40oC and 150oC to remove volatiles selected from ammonia, the protic substance and mixtures thereof.

10. The process as claimed in anyone of claims 8 or 9, wherein the process further comprising the step of:
optionally diluting the master-batch with a diluent to obtain a modified master-batch.

11. The process as claimed in anyone of claims 8 to 10, further comprising the step of adding a reactive organopolysiloxane base to the master-batch or the modified master-batch to form a liquid silicone rubber base polymer composition.

12. The process as claimed in anyone of claims 8 to 11, further comprising the step of adding an extender filler.

13. The process as claimed in anyone of claims 8 to 13, wherein the reactive organopolysiloxane comprising atleast a functional group selected from hydroxyl, alkoxy, vinyl and mixtures thereof.

14. The process as claimed in anyone of claims 8 to 14, wherein the reinforcing filler is selected from pyrogenic silica, precipitated silica, silicon-aluminum mixed oxides, pyrogenic titanium dioxide or its mixtures thereof.

15. The process as claimed in anyone of claims 8 to 15, wherein the pretreatment agent is selected from an organosilane, an organosilazanes,an organosiloxanes or its mixtures thereof.

16. The process as claimed in anyone of claims 8 to 15, further comprising the step of adding a hardner composition post addition of reactive organopolysiloxane base to the master-batch or the modified master-batch to form crosslinkable RTV-2 silicone composition.

17. A crosslinkable RTV-2 silicone composition, comprising:
storage stable and flowable master-batch composition having a pretreated reinforcing filler
having blocked surface hydroxyl groups with surface hydroxyl content less than 0.01 parts per million of the masterbatch composition.

18. A crosslinkable RTV-2 silicone as claimed in claim 17 comprisng liquid silicone rubber base polymer and a hardner composition.

19. A crosslinkable RTV-2 silicone composition as claimed in anyone of claims 17 or 18 obtained by the process according to any one of claims 8 to16.

20. A crosslinkable RTV-2 silicone composition as claimed in anyone of claims 17 or 18, wherein the hardener composition comprising atleast one crosslinking agent and atleast one catalyst.

21. A crosslinked RTV-2 silicone comprising:
cross linked liquid silicone rubber base polymer with hardener composition including
storage stable and flowable master-batch composition having a pretreated reinforcing filler
having blocked surface hydroxyl groups with surface hydroxyl content less than 1000 parts per million of the masterbatch composition .

22. An emulsion composition comprising the master batch or modified master batch of anyone of claims 1 to 7.

Dated this the 15th day of October 2016 Anjan Sen
Of Anjan Sen and Associates
(Applicants Agent)