CA2095572A1 - Process for the continuous production of liquid silicone rubbers - Google Patents
Process for the continuous production of liquid silicone rubbersInfo
- Publication number
- CA2095572A1 CA2095572A1 CA002095572A CA2095572A CA2095572A1 CA 2095572 A1 CA2095572 A1 CA 2095572A1 CA 002095572 A CA002095572 A CA 002095572A CA 2095572 A CA2095572 A CA 2095572A CA 2095572 A1 CA2095572 A1 CA 2095572A1
- Authority
- CA
- Canada
- Prior art keywords
- coating
- diorganopolysiloxane
- mixture
- filler
- mixing
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K9/00—Use of pretreated ingredients
- C08K9/04—Ingredients treated with organic substances
- C08K9/06—Ingredients treated with organic substances with silicon-containing compounds
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L83/00—Compositions of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon only; Compositions of derivatives of such polymers
- C08L83/04—Polysiloxanes
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G77/00—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule
- C08G77/04—Polysiloxanes
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G77/00—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule
- C08G77/04—Polysiloxanes
- C08G77/06—Preparatory processes
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G77/00—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule
- C08G77/04—Polysiloxanes
- C08G77/20—Polysiloxanes containing silicon bound to unsaturated aliphatic groups
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- Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- Processes Of Treating Macromolecular Substances (AREA)
- Compositions Of Macromolecular Compounds (AREA)
- Silicon Polymers (AREA)
Abstract
Dp/bo/4E-w Process for the continuous production of liquid silicone rubbers ABSTRACT
A Process for the continuous production of crosslinking silicone rubbers based on crosslinkable diorganopolysiloxane is disclosed wherein the process comprises a) mixing diorganopolysiloxane with at least one filler and at least one coating agent, b) in-situ coating of the filler subject to continuous separation by distillation of excess coating agent before or during the coating reaction and recycling of the condensates thereof, c) degassing the mixture from step b) and, optionally, re-dilution with diorganopoly-siloxanes, and d) mixing the mixture from step c) with a crosslinking agent or catalyst, wherein the average total residence-time of the diorganopolysiloxane in steps a) to c) amounts to more than 15 minutes.
Le A 27 982-Foreign Countries
A Process for the continuous production of crosslinking silicone rubbers based on crosslinkable diorganopolysiloxane is disclosed wherein the process comprises a) mixing diorganopolysiloxane with at least one filler and at least one coating agent, b) in-situ coating of the filler subject to continuous separation by distillation of excess coating agent before or during the coating reaction and recycling of the condensates thereof, c) degassing the mixture from step b) and, optionally, re-dilution with diorganopoly-siloxanes, and d) mixing the mixture from step c) with a crosslinking agent or catalyst, wherein the average total residence-time of the diorganopolysiloxane in steps a) to c) amounts to more than 15 minutes.
Le A 27 982-Foreign Countries
Description
J ~ r~ ~
, i 12~/knl~E~w 5 Process for the continuous productioll of liquid silicone rubbers _ The object of the present invention is a process for the continuous production of 10 silicone rubbers, in particular of two-component liquid silicone rub'oers.
Rub~rs of this type consist essentially of crosslinlcable diorganosilo%anes and silylated finely-dispersed silicic acids9 as well as small amounts of crosslir~ng agents, catalysts and inhibitors, and, optionally9 other non-reinforcing or semi-reinforcing 1 5 fillers.
There are several well-known processes (e.g. ~3P-A-2589159, US-4,737,561, US-4,649,005~ for the continuous production of silicone rubbers.
20 US-4,649,005 dessribes the continuous production of base r~xtures for liquid silicone rubbers which crosslink after addition of crosslinking agent and catalyst in accordance with the addition principle. In this connection a mixed process is described in which compounding is effected in a temperature range firOQI 200C to 300C whereby t~ecoating of the filler to allow reaction with the silicon polymer is avoided.
~P-A 258 159 discloses a process for the continuous production of base mixtures for silicone elastomers that are capable of hot vulcanisation and based on highly viscous polymers with a viscosity of 1000 Pa.x. 1l1 this connection so-called anti-structural agents are also used which according to the description can be, e.g. a,~
30 dihydroxydiorganopolysiloxanes with a viscosity of 20 to 100 mPas. Silazanes are only mentioned in connec~ion with t~e use of coated fillers (exterllal coating).A further characteristic of the hlown process is a short residence-time of 30 seconds to 10 minutes.
35 It is an aim of the present invention, on the other hand, to provide a process for the tot~l, continuous compounding of crosslinkable silicone rubbers,~in particular for the parallel production of bo~h the components of li~quid silicone rubbçrs.
A 27 282-Foreign Countries - 1 -, ..
An aiin of the present invention is ~urthermore the continuous implementation ofin-situ coating, as completely as possible, of f~nely-dispersed silica with silazanes and/or silanols.
10 Such in-situ coating with silazanes and/or silanols requires longer residence-~mes than compounding processes with other filler-coating agents (e.g. dihydroxy-diorganopoly-siloxanes~, which only cover the filler s~face incompletely. Incompletely silylated (made hydrophobic) fillers result however in relatively high mixing viscosi1des and a strong crepe hardening (increase in viscosi~ after storage). For this reason silicone 15 rubbers with ill-situ silazane coating, produced in the hereto~ore described aggregates with short residence-time, exhibit the disadvantages of the other coa~ng agents described above.
A further aim of the present invention consists in keeping to a mil~imum the amount of 2o coating agent required for the coating step.
The problem is solved according to the invention in that the coating agent is used in excess in a continuous n~ing process, excess coating agent is distilled off be~ore or during the actual coating reaction, and the distilled coating agent is recycled.
With the process according to the invention it is possible to produce all formulations which have hitherto becn produced discontinuously. Fur~hermore, in comparison with the discontinuous mode of operation whereby the same product quality is obtained, the process according to the invention pennits the required amounts of coating agents 30 to be reduced.
Polydiorg~nosiloxanes of the formula R' . R R' R - Si- o - - SiO- - Si - R
R~ Rl x A 27 9~2-FC - 2 -: ::
, 2 (~ r~ ~
5 can be used, wherein R and R' are alkyl residues with 1 to 8 carbon atoms, aryl residues, vinyl residues and fluoroaL~cyl residues with 3 to 8 car~on atoms, and x has a value from 10 to 6000.
:
Instead of diorganopolysiloxanes, copolymers with units not containing silicon can also be used. In aWition, branched polymers, namely those of the formulae SiO4/2, 15 RSiO3/2 and R3SiOl/2 can also be used, wherein R has the meaning s~ed above.
Hydrogen siloxanes having at least 3 SiH groups or peroxides can be used as crosslinking agents. Fur~ermore, chain-extenders with 2 SiH groups can also be used. All~nols can be used as inhiWtors. Suitable catalysts for the crosslin~dng20 reaction are vinylsiloxane-platinum complexes.
By way of reinforcing fillers, fumed or precipitated finely-disperæd silica with a BE~T
surface of more than 50 m2/g can be use~. Such fillers exhibit bulk densities of 0.1 kg/l, t~pically 0.05 down to 0.025 kg/l. In addition, carbon blacks and non-reinforcing 25 or semi-reinforcing fillers can also be used, such as diatomaceous e~lrths or quartz powders. Thc amount of filler shall be about 10 to 60 % by weight of the total mixture. As coating agents, hexaalkyldisilaz~nes with methyl and vinyl groups can be used together with water. ~urthermore, silanols are also suitable, e,g. trimethylsilanol and dimethylvinylsilanol, together with small amounts of aqueous solution OI a~nmonia 30 or disi1azane/water by way of coating agent"n amounts to ensure an aLlcaline pH of the solution (pH >7) Mixture of silanols can also be used.
The amount of coating agent shall at leas~ be su~ficient for a complete coating of the ~iller particles, tyically at least abou~ 0,12 g of coating agent per 300 m2 of filler 35 surface area Le A 27 982-FC - 3 -:;, ,, ;
2~9~72 5 In the first step of the process according to the invention the diorganopolysiloxanesare com~Jined with the fillers and coating agents in a mixer working continuous~y. The air ca~ied in with the filler is withdrawn through domes in which separation of filler particles and air takes place. Large-volume mixers with ~ree volume and which are capable of being cooled are suitable for this step; e.g. a Contin~lous Universal Mixer 10 omrnercially available from Baker Perkins, or an Ap-conti reactor, commercially available from ~ist, with a discharge screw.
In the second step of the process according to the invention, in-situ coating of the fillers employed is ef~ected with the coating agents at the boiling-temperature of the 15 reacted or original coating agents (silanols). The distillates arising are condensed in a cooler, separated into org~c and aqueous phase, and either the organic phase only or both phases are in part recycled into the mixer. In a further variant a parlial flow of the distillates is conveyed to the f;~st mixer. Mixers capable of being heated and having rela~vely high residence-time and a free volume are suitable for this step, e.g.
20 an Ap-conti reacts~r, commercially available from List, with discharge s¢rew.
In the third step, the residues of coating agent that are still prese~ are removed a~
elevated temperature (up to 1 80C) ~n a vacuum in a double-shafted screw, e.g. ZSK
commercially available from Werner u. Pfleiderer, or a double-shafted screw availabh 25 from Baker Perlcins, and are optionally re-diluted in the second part of the aggregate with polydiorganosiloxane.
I;or example, a Co-Kneader commerc,ially available from Buss is also suitable for this step of the process.
In the last step of ~e process according to the invention - in case both components of liquid silicone rubbers are being produced in parallel - ~e mixh~e is l'irs~dy split into two partial flows with separate conveyor pumps and then combined n~xing ~d cooling is effected in static mixers capable of being cooled. One partial ~ow is mixed with catalyst and diorganopolysiloxanes and the other partial flow is mixed wi~
crosslinking agents, inhibitors and diorganopolysiloxane.
Le A 27 982_FC - 4 -:'` ~ , ;
- .
~09~7~
5 Alternatively, in the case of production of only one component, the last step of the process can be effected together with the third step in an aggregate (e.g. a double-shafted screw of sufficient leng~h).
Fig. 1 describes an example of a plant for implementing the process according to the 10 invention. The figures in the diagrarn describe in particular:
Mixer for the 1 st step:
Ap-conti reactor made by List, type AR 12C, 15 having a free volume of 30,6 l, 2 Mixer for the 2nd step:
Ap-conti reactor made by Lis~, type AP 12C, 20 3 Mixer for the 3rd step:
Double-shafted screw available from Werner und Pfleiderer, type ZSK 37, having a free volume of 1,31, 25 4 Condensation de~ice for silanol, 5, 6 Static mixers for mixing catalyst or crosslinking agent and inhibitors for producing components A
and B of the two-component system, e.g. type SMX
30 available from Sulzer.
The polyrner mixture and the f;ller are introduced into the mixer through feed lines 7 and 8, water is introduced via feed line 9, and the coating agent via feed line 10~ in each case via metering devices. Air contai~ing powder is withdrawn via line 11.
The temper~ture in m~xer 1 is maintained at 20 to 40C; the pressure is sligh~y below normal pressure - e.g. not more than 100 mbar below normal pressure. The L e A 27 982-FC - S -.
, , ~
. ~
.
2095t~72 5 residence-time in mixer 1 lies between 5 and 40 minutes in order to ensure sufflcient mixing of filler, polymer and coating agent.
The mix~ure is conveyed to mixer 2 through line 12. Here the reaction between coating agent and filler takes place subject to the formation of silanols at a 10 temperature of 80 to 110C and at normal pressure. The silanolsj water and other volatile components leave n~ixer 2 at line 13. Silanols are condensed in condenser 4 and corlveyed back into the mixture through line 14, op~ionally partly ~hrough line 15.
Non-condensed volatile components leave the system vialine 16.
15 ~e mixture from mixer 2 is conveyed via line 17 to mixer 3 after a residence-time of 10 to 40 minutes. Here the reaction is completed at a ternperature of 130 to 160C
and remaining volatile components are withdrawn via line 18 at a pressure of less than 100 mbar. Silicone polymers of low viscosity ("re-dilution polymers") can be conveyed through line 19 to adjust the viscosity of the rnixture. The liquid silicone 20 ~ubber, still free of catalyst or crosslinhng agent, leaves mixer 3 at 20.
Further admixture of catalyst 26 for producing cornponent A and of crosslinldng agent and, optionally, of inhibitors 25 for producing component B now takes place in separate rnixers 5 and 6 respectively, either simultaneously in parallel, wherein the 25 polymer feed is split up in line 20 by a divîder 21 into lines 22 and 23, or in series, when 21 denotes a valve.
Re-dilution polymers can likewise be conveyed to the mixers 5 and 6 via lines 24.
~o The following examples illustrate the present invention but are not intended to lirnit its scope in any way.
-: :, , , ,. 1 ,. .
~ , . . .
2 ~ 7 ~
5 ~me!~
Use is made of a device such as depicted in Fig. 1.
To mixer 1 are charged: 0 1~ kg/h of apolydimethylsiloxanemixturewith vinyl terminal groups, polymer 1 (visc.: 10 Pa.s), polymer 2 (~isc.: 65 Pa.s), mixingratio: 1:2.5;
1.1 kg~ hexamethyldisilazane as coating agen~;
15 0.6 kg/h water and 8.3 k~/h fumed silica (BET 300 m2/g~.
The temperature is maintained at 30C. The air containing powder is removed at 0.98 bar. The aYerage residence-~rne of the polysiloxane mixt~ arnounts to 34 minutes.
Mixer 2:
0.5 kg/h organic phase is condensed and recycled into n~ixer 2. The residence~meamounts to 33 minutes, the pressu~e 1 bar, the temperature 90 to 100C.
z~ Mixer 3:
Temperature = 150C
Vacuum: 20 mbar; residence-time: 2 minutes.
To bring about re-dilution, 3.7 kg/h of polymer 1 are adde~!.
3t~ Separation ratio of the main flow: 1:1.
Static mixer 5:
1.9 g/h Pt catalyst and, to bring about further re-dilution, 1600 g~ of polymer 1 are added. Residence-time 2.5 minutes.
Le A ~-FC - 7 -,, . ;. .
.. .
....
2 0 9 ~ ~ 7 2 5 Static mixer 6:
500 glh hydrogensiloxane ~4 mmol SiHJg) as crosslinking agent and 13 ~/h 2-methylbutyne-3-ol-2 as inhibitor, as well as llQ0 g/h of polymer 1, to bdng about further re-dilution, are added. Residence-time 2.5 minutes, 10 The two par~al flows have a discharge temperature of 50C. After mixing of the two components and curing at 175C
(10 min) a highly transparent vulcanisate is obtained.
Exa~pplQ2 :.
Example 1 is repeated, with the difference that to mixer 1 are charged 1.1 kg/h of a mixture consisting of 20 parts hexame~yldisilazane and 1 part tetramethyldivinyldisilazane by way of coating agent.
After mixing of the components ~ and B and curing at 175C for over 10 min a highly 2~ transparent vulcanisate is obtained.
Example 1 is repeated, with the difference that to rnixer 1 are charged 1.3 k~/h trimethylsilanol and 0.005 kg/h aqueous solution of ammonia as the coating agent, and no extra water is supplied.
35 After mixing of the components A and B and curing at 175C for over 10 rnin a highly transparent vulcanisate is obtained.
Le A 27 ~82-FC - 8 -~iO~5il)7~
5 E~am Device as in Example 1.
To mixer 1 are charged:
10 38 l~g/h of a polydime~ylsiloxane mixture with vinyl terminal groups, polymer 1 (visc.: 10 Pas), polymier 2 ~visc.: 65 Pas), mixing ratio: 1:2.5;
2.2 kg/.h hexamie~hyldisilazane;
15 1.2 k~/h water and 16.6 kg/.h compressed fumed silica (BET 300 m2/g).
.
Temperature: 33C, pressure: 0.98 bar; residence-time: 17 minutes.
20 Mixer 2:
Temperature = 90 to 100C, residence-time: 16 minutes, pressure: 1 bar, condensate:
1.0 g/hi organic phase are recycled into mixer 2.
Mixer 3:
Temperature = 150C, pressure: 20 mbar, residence-time: 1 minute, re~dilution: 7.4 kg/h of polymer 1.
Separation ratio of the main flow: 1:1.
30 Static mixer 4: '.
, i 12~/knl~E~w 5 Process for the continuous productioll of liquid silicone rubbers _ The object of the present invention is a process for the continuous production of 10 silicone rubbers, in particular of two-component liquid silicone rub'oers.
Rub~rs of this type consist essentially of crosslinlcable diorganosilo%anes and silylated finely-dispersed silicic acids9 as well as small amounts of crosslir~ng agents, catalysts and inhibitors, and, optionally9 other non-reinforcing or semi-reinforcing 1 5 fillers.
There are several well-known processes (e.g. ~3P-A-2589159, US-4,737,561, US-4,649,005~ for the continuous production of silicone rubbers.
20 US-4,649,005 dessribes the continuous production of base r~xtures for liquid silicone rubbers which crosslink after addition of crosslinking agent and catalyst in accordance with the addition principle. In this connection a mixed process is described in which compounding is effected in a temperature range firOQI 200C to 300C whereby t~ecoating of the filler to allow reaction with the silicon polymer is avoided.
~P-A 258 159 discloses a process for the continuous production of base mixtures for silicone elastomers that are capable of hot vulcanisation and based on highly viscous polymers with a viscosity of 1000 Pa.x. 1l1 this connection so-called anti-structural agents are also used which according to the description can be, e.g. a,~
30 dihydroxydiorganopolysiloxanes with a viscosity of 20 to 100 mPas. Silazanes are only mentioned in connec~ion with t~e use of coated fillers (exterllal coating).A further characteristic of the hlown process is a short residence-time of 30 seconds to 10 minutes.
35 It is an aim of the present invention, on the other hand, to provide a process for the tot~l, continuous compounding of crosslinkable silicone rubbers,~in particular for the parallel production of bo~h the components of li~quid silicone rubbçrs.
A 27 282-Foreign Countries - 1 -, ..
An aiin of the present invention is ~urthermore the continuous implementation ofin-situ coating, as completely as possible, of f~nely-dispersed silica with silazanes and/or silanols.
10 Such in-situ coating with silazanes and/or silanols requires longer residence-~mes than compounding processes with other filler-coating agents (e.g. dihydroxy-diorganopoly-siloxanes~, which only cover the filler s~face incompletely. Incompletely silylated (made hydrophobic) fillers result however in relatively high mixing viscosi1des and a strong crepe hardening (increase in viscosi~ after storage). For this reason silicone 15 rubbers with ill-situ silazane coating, produced in the hereto~ore described aggregates with short residence-time, exhibit the disadvantages of the other coa~ng agents described above.
A further aim of the present invention consists in keeping to a mil~imum the amount of 2o coating agent required for the coating step.
The problem is solved according to the invention in that the coating agent is used in excess in a continuous n~ing process, excess coating agent is distilled off be~ore or during the actual coating reaction, and the distilled coating agent is recycled.
With the process according to the invention it is possible to produce all formulations which have hitherto becn produced discontinuously. Fur~hermore, in comparison with the discontinuous mode of operation whereby the same product quality is obtained, the process according to the invention pennits the required amounts of coating agents 30 to be reduced.
Polydiorg~nosiloxanes of the formula R' . R R' R - Si- o - - SiO- - Si - R
R~ Rl x A 27 9~2-FC - 2 -: ::
, 2 (~ r~ ~
5 can be used, wherein R and R' are alkyl residues with 1 to 8 carbon atoms, aryl residues, vinyl residues and fluoroaL~cyl residues with 3 to 8 car~on atoms, and x has a value from 10 to 6000.
:
Instead of diorganopolysiloxanes, copolymers with units not containing silicon can also be used. In aWition, branched polymers, namely those of the formulae SiO4/2, 15 RSiO3/2 and R3SiOl/2 can also be used, wherein R has the meaning s~ed above.
Hydrogen siloxanes having at least 3 SiH groups or peroxides can be used as crosslinking agents. Fur~ermore, chain-extenders with 2 SiH groups can also be used. All~nols can be used as inhiWtors. Suitable catalysts for the crosslin~dng20 reaction are vinylsiloxane-platinum complexes.
By way of reinforcing fillers, fumed or precipitated finely-disperæd silica with a BE~T
surface of more than 50 m2/g can be use~. Such fillers exhibit bulk densities of 0.1 kg/l, t~pically 0.05 down to 0.025 kg/l. In addition, carbon blacks and non-reinforcing 25 or semi-reinforcing fillers can also be used, such as diatomaceous e~lrths or quartz powders. Thc amount of filler shall be about 10 to 60 % by weight of the total mixture. As coating agents, hexaalkyldisilaz~nes with methyl and vinyl groups can be used together with water. ~urthermore, silanols are also suitable, e,g. trimethylsilanol and dimethylvinylsilanol, together with small amounts of aqueous solution OI a~nmonia 30 or disi1azane/water by way of coating agent"n amounts to ensure an aLlcaline pH of the solution (pH >7) Mixture of silanols can also be used.
The amount of coating agent shall at leas~ be su~ficient for a complete coating of the ~iller particles, tyically at least abou~ 0,12 g of coating agent per 300 m2 of filler 35 surface area Le A 27 982-FC - 3 -:;, ,, ;
2~9~72 5 In the first step of the process according to the invention the diorganopolysiloxanesare com~Jined with the fillers and coating agents in a mixer working continuous~y. The air ca~ied in with the filler is withdrawn through domes in which separation of filler particles and air takes place. Large-volume mixers with ~ree volume and which are capable of being cooled are suitable for this step; e.g. a Contin~lous Universal Mixer 10 omrnercially available from Baker Perkins, or an Ap-conti reactor, commercially available from ~ist, with a discharge screw.
In the second step of the process according to the invention, in-situ coating of the fillers employed is ef~ected with the coating agents at the boiling-temperature of the 15 reacted or original coating agents (silanols). The distillates arising are condensed in a cooler, separated into org~c and aqueous phase, and either the organic phase only or both phases are in part recycled into the mixer. In a further variant a parlial flow of the distillates is conveyed to the f;~st mixer. Mixers capable of being heated and having rela~vely high residence-time and a free volume are suitable for this step, e.g.
20 an Ap-conti reacts~r, commercially available from List, with discharge s¢rew.
In the third step, the residues of coating agent that are still prese~ are removed a~
elevated temperature (up to 1 80C) ~n a vacuum in a double-shafted screw, e.g. ZSK
commercially available from Werner u. Pfleiderer, or a double-shafted screw availabh 25 from Baker Perlcins, and are optionally re-diluted in the second part of the aggregate with polydiorganosiloxane.
I;or example, a Co-Kneader commerc,ially available from Buss is also suitable for this step of the process.
In the last step of ~e process according to the invention - in case both components of liquid silicone rubbers are being produced in parallel - ~e mixh~e is l'irs~dy split into two partial flows with separate conveyor pumps and then combined n~xing ~d cooling is effected in static mixers capable of being cooled. One partial ~ow is mixed with catalyst and diorganopolysiloxanes and the other partial flow is mixed wi~
crosslinking agents, inhibitors and diorganopolysiloxane.
Le A 27 982_FC - 4 -:'` ~ , ;
- .
~09~7~
5 Alternatively, in the case of production of only one component, the last step of the process can be effected together with the third step in an aggregate (e.g. a double-shafted screw of sufficient leng~h).
Fig. 1 describes an example of a plant for implementing the process according to the 10 invention. The figures in the diagrarn describe in particular:
Mixer for the 1 st step:
Ap-conti reactor made by List, type AR 12C, 15 having a free volume of 30,6 l, 2 Mixer for the 2nd step:
Ap-conti reactor made by Lis~, type AP 12C, 20 3 Mixer for the 3rd step:
Double-shafted screw available from Werner und Pfleiderer, type ZSK 37, having a free volume of 1,31, 25 4 Condensation de~ice for silanol, 5, 6 Static mixers for mixing catalyst or crosslinking agent and inhibitors for producing components A
and B of the two-component system, e.g. type SMX
30 available from Sulzer.
The polyrner mixture and the f;ller are introduced into the mixer through feed lines 7 and 8, water is introduced via feed line 9, and the coating agent via feed line 10~ in each case via metering devices. Air contai~ing powder is withdrawn via line 11.
The temper~ture in m~xer 1 is maintained at 20 to 40C; the pressure is sligh~y below normal pressure - e.g. not more than 100 mbar below normal pressure. The L e A 27 982-FC - S -.
, , ~
. ~
.
2095t~72 5 residence-time in mixer 1 lies between 5 and 40 minutes in order to ensure sufflcient mixing of filler, polymer and coating agent.
The mix~ure is conveyed to mixer 2 through line 12. Here the reaction between coating agent and filler takes place subject to the formation of silanols at a 10 temperature of 80 to 110C and at normal pressure. The silanolsj water and other volatile components leave n~ixer 2 at line 13. Silanols are condensed in condenser 4 and corlveyed back into the mixture through line 14, op~ionally partly ~hrough line 15.
Non-condensed volatile components leave the system vialine 16.
15 ~e mixture from mixer 2 is conveyed via line 17 to mixer 3 after a residence-time of 10 to 40 minutes. Here the reaction is completed at a ternperature of 130 to 160C
and remaining volatile components are withdrawn via line 18 at a pressure of less than 100 mbar. Silicone polymers of low viscosity ("re-dilution polymers") can be conveyed through line 19 to adjust the viscosity of the rnixture. The liquid silicone 20 ~ubber, still free of catalyst or crosslinhng agent, leaves mixer 3 at 20.
Further admixture of catalyst 26 for producing cornponent A and of crosslinldng agent and, optionally, of inhibitors 25 for producing component B now takes place in separate rnixers 5 and 6 respectively, either simultaneously in parallel, wherein the 25 polymer feed is split up in line 20 by a divîder 21 into lines 22 and 23, or in series, when 21 denotes a valve.
Re-dilution polymers can likewise be conveyed to the mixers 5 and 6 via lines 24.
~o The following examples illustrate the present invention but are not intended to lirnit its scope in any way.
-: :, , , ,. 1 ,. .
~ , . . .
2 ~ 7 ~
5 ~me!~
Use is made of a device such as depicted in Fig. 1.
To mixer 1 are charged: 0 1~ kg/h of apolydimethylsiloxanemixturewith vinyl terminal groups, polymer 1 (visc.: 10 Pa.s), polymer 2 (~isc.: 65 Pa.s), mixingratio: 1:2.5;
1.1 kg~ hexamethyldisilazane as coating agen~;
15 0.6 kg/h water and 8.3 k~/h fumed silica (BET 300 m2/g~.
The temperature is maintained at 30C. The air containing powder is removed at 0.98 bar. The aYerage residence-~rne of the polysiloxane mixt~ arnounts to 34 minutes.
Mixer 2:
0.5 kg/h organic phase is condensed and recycled into n~ixer 2. The residence~meamounts to 33 minutes, the pressu~e 1 bar, the temperature 90 to 100C.
z~ Mixer 3:
Temperature = 150C
Vacuum: 20 mbar; residence-time: 2 minutes.
To bring about re-dilution, 3.7 kg/h of polymer 1 are adde~!.
3t~ Separation ratio of the main flow: 1:1.
Static mixer 5:
1.9 g/h Pt catalyst and, to bring about further re-dilution, 1600 g~ of polymer 1 are added. Residence-time 2.5 minutes.
Le A ~-FC - 7 -,, . ;. .
.. .
....
2 0 9 ~ ~ 7 2 5 Static mixer 6:
500 glh hydrogensiloxane ~4 mmol SiHJg) as crosslinking agent and 13 ~/h 2-methylbutyne-3-ol-2 as inhibitor, as well as llQ0 g/h of polymer 1, to bdng about further re-dilution, are added. Residence-time 2.5 minutes, 10 The two par~al flows have a discharge temperature of 50C. After mixing of the two components and curing at 175C
(10 min) a highly transparent vulcanisate is obtained.
Exa~pplQ2 :.
Example 1 is repeated, with the difference that to mixer 1 are charged 1.1 kg/h of a mixture consisting of 20 parts hexame~yldisilazane and 1 part tetramethyldivinyldisilazane by way of coating agent.
After mixing of the components ~ and B and curing at 175C for over 10 min a highly 2~ transparent vulcanisate is obtained.
Example 1 is repeated, with the difference that to rnixer 1 are charged 1.3 k~/h trimethylsilanol and 0.005 kg/h aqueous solution of ammonia as the coating agent, and no extra water is supplied.
35 After mixing of the components A and B and curing at 175C for over 10 rnin a highly transparent vulcanisate is obtained.
Le A 27 ~82-FC - 8 -~iO~5il)7~
5 E~am Device as in Example 1.
To mixer 1 are charged:
10 38 l~g/h of a polydime~ylsiloxane mixture with vinyl terminal groups, polymer 1 (visc.: 10 Pas), polymier 2 ~visc.: 65 Pas), mixing ratio: 1:2.5;
2.2 kg/.h hexamie~hyldisilazane;
15 1.2 k~/h water and 16.6 kg/.h compressed fumed silica (BET 300 m2/g).
.
Temperature: 33C, pressure: 0.98 bar; residence-time: 17 minutes.
20 Mixer 2:
Temperature = 90 to 100C, residence-time: 16 minutes, pressure: 1 bar, condensate:
1.0 g/hi organic phase are recycled into mixer 2.
Mixer 3:
Temperature = 150C, pressure: 20 mbar, residence-time: 1 minute, re~dilution: 7.4 kg/h of polymer 1.
Separation ratio of the main flow: 1:1.
30 Static mixer 4: '.
3.8 g/h Pt catalyst and 3200 g/h of polymer 1, : ;
residence-time: 1.3 minutes.
Stadc rnixer 5:
1000 g/h hydrogensiloxane (4 mmol SiH/g), 26 g/h 2-methylbutyne-3-ol-2 and . ~
Le A 27 982-FC - 9 -: : ~ . . ~ - .
, - . .. .
, 2~95~72 5 2200 g/h of polymer 1, residence-time: 1.3 minutes.
The two pa~al flows have a discharge temperature of 61C. After mixing of the two components and curing at 175C
10 (10 min) a highly ~ansparent vulcanisate is obtaine~l.
~Q~ ' .
Apparatus as in Example 1.
15 To mixer 1 are charged:
19 kg/h of a polydimethylsiloxane mixture wi~h vinyl terminal groups, polymer 1 (visc.: 10 Pas), polymer 2 (visc.: 65 Pa.s), mixirig ratio: 1:2.5;
1.0 kg/h hexamethyldisilazane, 0.3 k~ org. phase of the condensates from mixer 2, 0.6 k~h water and 8.3 l~g/ fumed silica (13ET 300 m2/g).
25 Temperature: 30C, pressure: 0.98 bar; residence-time: 34 miautes.
Mixer 2;
Temperature = 90 to 100C, pressure: I bar, residence-time: 34 millutes;
~o Condensate:
0.5 glh of organic phase, of which 0.2 kg/h are recycled into mixer 2.
Mixer 3:
Temperature = 1 50C, pressure: 20 mbar, ~esidence-time: 2 minutes 35 Re-dilution: 3.7 kg/h of polymer }.
Separation ratio of the main flow~
. ~ , . , .. ... . . .
:~ :
;~ . ~' - : ~, 209~ 72 Static mixer 4~
1.9 g/h Pt catalyst and 1600 g/h of polymer 1.
Residence-time: 2.5 minutes.
Static mixer 5:
500 g/h hydrogensiloxane (4 mmol SiH/g), 13 ~/h 2-methylbu~ne-3-ol-2 and 1 lOû g/h of polymer 1.
~, 5 Residence-time: 2.5 minutes.
The two partial flows have a discharge temperaeure of 50C. Afier mixing of the two components and curing at 175C
(10 n~in) a highly transparent vulcanisate is obtained.
~e~ , , .
Example 1 is repeated7 with the differ~nce that to each of static mixers 4 and 5 are added 70 g/h 215-dimethyl-2,5-(tert-butylperoxy)-hexane instead of catalyst, crosslinking agent, inhibitor and dilution polymer.
'' 3~ The one-component system obtained results after curing at 175C for over 10 min in a highly transparent vulcanisate.
~mllLel (reference) 35 Instead of mixers 1, 2 and 3, use is made of a double-shafted screw of ~yp,e æK
34/2VlS00, available from Werner und Pfleiderer.
Le A ~
, . :
;
~a~a~72 5 Into the screw are charged:
2.4 kglh of a polydimethylsiloxane mixture with vinyl terminal groups, polymer 1 (visc.: 10 Pa.s), polymer 2 (visc.: 65 Pas), mixingratio: 1:2.5;
0.14 kglll hexamethyldisilazane 0.û8 kg/h water and 1.05 kg/h fumed silica (BET 300 m2/g).
15 A short distance be~ore the end of the screw re-dilu~ion takes place with:
0.47kg/h of polymer 1.
The total residence-time in the screw arnounts to 5.7 minutes. A short distance behind the ir~et the temperature is maintained at 100C for in-situ coating of the filler 20 material. The pressure here amounts to about 1.5 bar.
At the back end of ehe screw the temperature is raised to 160C with a view to vapour discharge at a pressure of 20 mbar.
The discharge temperature sti}l amounts to 150C.
25 The discharge pressure amounts to about 2 bar.
The base rnixture produce~l in this way (without cat~lyst or crosslinking agent)exhibits a doubling of viscosity a~ter just a short storage ~ime (2 weeks) at room temperature.
~0 Table 1 shows the characteristics of the rubbers and vulcan~isates obtained from t~e Examples.
Le A 27 ~2-FC - 12 -- . . -, .- ~ ,. . . .
, :: - ::
,:
20~ 72 5 Ta~lelL
Example: 1 2 3 4 5 6 7 Rubber: Component B Base mixture Viscosity ~Pas~ (D=10/s) 710 700 720 690 715 810 740 Vlsc.after63 days 720 750 760 800 770 830 >5000 Vulcanisate:
Hardness (Shore A) 35 45 36 34 35 38 - ~
Tensile strength (MPa) 9.2 9.5 9.3 9.0 9.3 9.4 - :
Elongation at break (q'o) 920 800 880 930 910 800 Transparency 0.05 0.07 0.06 0.07 0.06 0.06 -(2 mm, 600 nm) , .
.
Le A 27 982-F~ - l3 -.
residence-time: 1.3 minutes.
Stadc rnixer 5:
1000 g/h hydrogensiloxane (4 mmol SiH/g), 26 g/h 2-methylbutyne-3-ol-2 and . ~
Le A 27 982-FC - 9 -: : ~ . . ~ - .
, - . .. .
, 2~95~72 5 2200 g/h of polymer 1, residence-time: 1.3 minutes.
The two pa~al flows have a discharge temperature of 61C. After mixing of the two components and curing at 175C
10 (10 min) a highly ~ansparent vulcanisate is obtaine~l.
~Q~ ' .
Apparatus as in Example 1.
15 To mixer 1 are charged:
19 kg/h of a polydimethylsiloxane mixture wi~h vinyl terminal groups, polymer 1 (visc.: 10 Pas), polymer 2 (visc.: 65 Pa.s), mixirig ratio: 1:2.5;
1.0 kg/h hexamethyldisilazane, 0.3 k~ org. phase of the condensates from mixer 2, 0.6 k~h water and 8.3 l~g/ fumed silica (13ET 300 m2/g).
25 Temperature: 30C, pressure: 0.98 bar; residence-time: 34 miautes.
Mixer 2;
Temperature = 90 to 100C, pressure: I bar, residence-time: 34 millutes;
~o Condensate:
0.5 glh of organic phase, of which 0.2 kg/h are recycled into mixer 2.
Mixer 3:
Temperature = 1 50C, pressure: 20 mbar, ~esidence-time: 2 minutes 35 Re-dilution: 3.7 kg/h of polymer }.
Separation ratio of the main flow~
. ~ , . , .. ... . . .
:~ :
;~ . ~' - : ~, 209~ 72 Static mixer 4~
1.9 g/h Pt catalyst and 1600 g/h of polymer 1.
Residence-time: 2.5 minutes.
Static mixer 5:
500 g/h hydrogensiloxane (4 mmol SiH/g), 13 ~/h 2-methylbu~ne-3-ol-2 and 1 lOû g/h of polymer 1.
~, 5 Residence-time: 2.5 minutes.
The two partial flows have a discharge temperaeure of 50C. Afier mixing of the two components and curing at 175C
(10 n~in) a highly transparent vulcanisate is obtained.
~e~ , , .
Example 1 is repeated7 with the differ~nce that to each of static mixers 4 and 5 are added 70 g/h 215-dimethyl-2,5-(tert-butylperoxy)-hexane instead of catalyst, crosslinking agent, inhibitor and dilution polymer.
'' 3~ The one-component system obtained results after curing at 175C for over 10 min in a highly transparent vulcanisate.
~mllLel (reference) 35 Instead of mixers 1, 2 and 3, use is made of a double-shafted screw of ~yp,e æK
34/2VlS00, available from Werner und Pfleiderer.
Le A ~
, . :
;
~a~a~72 5 Into the screw are charged:
2.4 kglh of a polydimethylsiloxane mixture with vinyl terminal groups, polymer 1 (visc.: 10 Pa.s), polymer 2 (visc.: 65 Pas), mixingratio: 1:2.5;
0.14 kglll hexamethyldisilazane 0.û8 kg/h water and 1.05 kg/h fumed silica (BET 300 m2/g).
15 A short distance be~ore the end of the screw re-dilu~ion takes place with:
0.47kg/h of polymer 1.
The total residence-time in the screw arnounts to 5.7 minutes. A short distance behind the ir~et the temperature is maintained at 100C for in-situ coating of the filler 20 material. The pressure here amounts to about 1.5 bar.
At the back end of ehe screw the temperature is raised to 160C with a view to vapour discharge at a pressure of 20 mbar.
The discharge temperature sti}l amounts to 150C.
25 The discharge pressure amounts to about 2 bar.
The base rnixture produce~l in this way (without cat~lyst or crosslinking agent)exhibits a doubling of viscosity a~ter just a short storage ~ime (2 weeks) at room temperature.
~0 Table 1 shows the characteristics of the rubbers and vulcan~isates obtained from t~e Examples.
Le A 27 ~2-FC - 12 -- . . -, .- ~ ,. . . .
, :: - ::
,:
20~ 72 5 Ta~lelL
Example: 1 2 3 4 5 6 7 Rubber: Component B Base mixture Viscosity ~Pas~ (D=10/s) 710 700 720 690 715 810 740 Vlsc.after63 days 720 750 760 800 770 830 >5000 Vulcanisate:
Hardness (Shore A) 35 45 36 34 35 38 - ~
Tensile strength (MPa) 9.2 9.5 9.3 9.0 9.3 9.4 - :
Elongation at break (q'o) 920 800 880 930 910 800 Transparency 0.05 0.07 0.06 0.07 0.06 0.06 -(2 mm, 600 nm) , .
.
Le A 27 982-F~ - l3 -.
Claims (6)
1. Process for the continuous production of crosslinking silicone rubbers based on crosslinkable diorganopolysiloxane wherein the process comprises a) mixing diorganopolysiloxane with at least one filler and at least one coating agent, b) in-situ coating of the filler subject to continuous separation by distillation of excess coating agent before or during the coating reaction and recycling of the condensates thereof, c) degassing the mixture from step b) and, optionally, re-dilution with diorganopoly-siloxanes, and d) mixing the mixture from step c) with a crosslinking agent or catalyst, wherein the average total residence-time of the diorganopolysiloxane in steps a) to c) amounts to more than 15 minutes.
2. Process accoring to Claim 1, characterised in that hexamethyldisilazane, divinyl-tetramethylsilazane and water are used as coating agents.
3. Process according to Claim 1, characterised in that trimethylsilanol, dimethyl-vinylsilanol and small amounts of aqueous solution of ammonia or hexamethyldi-silazane/divinyltetramethylsilazane/water mixtures are used as coating agents.
4. Process according to Claim 1, characterised in that the process steps are carried out in a high-shear continuous mixing apparatus of large free volume.
5. Process according to Claim 1, characterised in that pyrogenic silica with a specific surface of over 50 m2/g is used as filler material.
Le A 27 982-FC - 14 -
Le A 27 982-FC - 14 -
6. Process according to Claim 1, wherein the mixture form step c) is divided into two partial flows wherein one partial flow is mixed with catalyst and diorganopoly-siloxanes and the other partial flow is mixed with crosslinking agents, inhibitors, and diorganopolysiloxane.
Le A 27 982-FC - 15 -
Le A 27 982-FC - 15 -
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP4215205.4-43 | 1992-05-08 | ||
| DE4215205A DE4215205C1 (en) | 1992-05-08 | 1992-05-08 | Process for the continuous production of liquid silicone rubbers |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2095572A1 true CA2095572A1 (en) | 1993-11-09 |
Family
ID=6458421
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002095572A Abandoned CA2095572A1 (en) | 1992-05-08 | 1993-05-05 | Process for the continuous production of liquid silicone rubbers |
Country Status (8)
| Country | Link |
|---|---|
| EP (1) | EP0568891B1 (en) |
| JP (1) | JP3279726B2 (en) |
| KR (1) | KR100256932B1 (en) |
| AT (1) | ATE177459T1 (en) |
| CA (1) | CA2095572A1 (en) |
| DE (2) | DE4215205C1 (en) |
| ES (1) | ES2131082T3 (en) |
| TW (1) | TW222289B (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6911495B2 (en) * | 2002-06-27 | 2005-06-28 | Wacker-Chemie Gmbh | Process for the continuous preparation of two-component addition-crosslinking silicone compositions |
| US9434137B2 (en) | 2008-08-08 | 2016-09-06 | Saint-Gobain Performance Plastics Corporation | Thermal spray masking tape |
Families Citing this family (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2287248B (en) * | 1994-03-10 | 1998-01-14 | Gen Electric | In-situ filler treating process for RTV silicones |
| EP0691373A1 (en) * | 1994-07-08 | 1996-01-10 | Dow Corning Corporation | Method for preparing organopolysiloxane bases and compositions therefrom |
| JP3694080B2 (en) * | 1995-11-30 | 2005-09-14 | 東レ・ダウコーニング株式会社 | Method for producing diorganopolysiloxane / fine powder silica mixture |
| JP3389797B2 (en) * | 1996-11-07 | 2003-03-24 | 信越化学工業株式会社 | Method for producing high-fatigue durable liquid silicone rubber composition |
| DE19653993A1 (en) * | 1996-12-21 | 1998-06-25 | Huels Silicone Gmbh | Process for the preparation of highly filled silicone polymer solid premixes |
| DE19809548A1 (en) * | 1998-03-05 | 1999-09-09 | Wacker Chemie Gmbh | Process for the continuous production of moisture-crosslinkable organopolysiloxane compositions |
| US6391234B1 (en) * | 1999-12-21 | 2002-05-21 | General Electric Company | Compounding filled silicone compositions |
| US6414054B1 (en) | 1999-12-21 | 2002-07-02 | General Electric Company | Continuous preparation of heat-vulcanizable silicone compositions |
| US6444154B1 (en) | 2000-12-20 | 2002-09-03 | General Electric Company | Continuous preparation of a liquid silicone rubber composition |
| KR100536120B1 (en) * | 2002-11-19 | 2005-12-14 | 엘에스전선 주식회사 | Preparatoin method of liquid silicone rubber forming material with good insulation-breakdown and adhesion properties |
| DE102007002379A1 (en) * | 2007-01-16 | 2008-07-17 | Wacker Chemie Ag | Process for the preparation of crosslinkable compositions based on organopolysiloxanes |
| JP5730764B2 (en) * | 2008-08-08 | 2015-06-10 | サン−ゴバン パフォーマンス プラスティックス コーポレイション | Thermal spray masking tape |
| CN102421828B (en) | 2009-05-13 | 2014-12-10 | 陶氏康宁公司 | Continuous process for polymerization and emulsification of siloxane |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1024234A (en) * | 1962-06-27 | 1966-03-30 | Midland Silicones Ltd | Improvements in or relating to siloxane elastomers |
| US4785047A (en) * | 1987-07-30 | 1988-11-15 | Dow Corning Corporation | Method for preparing clear polyorganosiloxane elastomers |
| JPH0684477B2 (en) * | 1988-08-23 | 1994-10-26 | 信越化学工業株式会社 | Organopolysiloxane composition |
| DE3839900A1 (en) * | 1988-11-25 | 1990-05-31 | Wacker Chemie Gmbh | METHOD FOR THE HYDROPHOBICATION OF SI-OH GROUPS CONTAINING PARTICULATE SOLID AND USE OF THE RECEIVED HYDROPHOBIC, PARTICULATE SOLID IN A METHOD FOR PRODUCING ELASTENOXY ORGANIZED HAZARDS |
| US5081172A (en) * | 1989-12-13 | 1992-01-14 | Dow Corning Corporation | Method to reduce compression set in silanol-containing silicone elastomer bases |
| FR2663340B1 (en) * | 1990-06-13 | 1994-04-08 | Rhone Poulenc Chimie | PROCESS FOR PREPARING MASSAGE IN DOUBLE-SCREW EXTRUDER FOR RTV SIH / SIVI COMPOSITIONS. |
| DE4103602A1 (en) * | 1991-02-07 | 1992-08-13 | Wacker Chemie Gmbh | METHOD FOR THE CONTINUOUS PRODUCTION OF HTV SILICONE MATERIALS |
-
1992
- 1992-05-08 DE DE4215205A patent/DE4215205C1/en not_active Expired - Fee Related
-
1993
- 1993-04-14 TW TW082102813A patent/TW222289B/zh active
- 1993-04-26 EP EP93106733A patent/EP0568891B1/en not_active Expired - Lifetime
- 1993-04-26 AT AT93106733T patent/ATE177459T1/en not_active IP Right Cessation
- 1993-04-26 ES ES93106733T patent/ES2131082T3/en not_active Expired - Lifetime
- 1993-04-26 DE DE59309420T patent/DE59309420D1/en not_active Expired - Lifetime
- 1993-04-30 JP JP12483493A patent/JP3279726B2/en not_active Expired - Fee Related
- 1993-05-05 CA CA002095572A patent/CA2095572A1/en not_active Abandoned
- 1993-05-07 KR KR1019930007815A patent/KR100256932B1/en not_active IP Right Cessation
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6911495B2 (en) * | 2002-06-27 | 2005-06-28 | Wacker-Chemie Gmbh | Process for the continuous preparation of two-component addition-crosslinking silicone compositions |
| US9434137B2 (en) | 2008-08-08 | 2016-09-06 | Saint-Gobain Performance Plastics Corporation | Thermal spray masking tape |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3279726B2 (en) | 2002-04-30 |
| DE4215205C1 (en) | 1994-01-05 |
| EP0568891B1 (en) | 1999-03-10 |
| KR100256932B1 (en) | 2000-05-15 |
| ES2131082T3 (en) | 1999-07-16 |
| TW222289B (en) | 1994-04-11 |
| JPH0632909A (en) | 1994-02-08 |
| ATE177459T1 (en) | 1999-03-15 |
| KR930023420A (en) | 1993-12-18 |
| DE59309420D1 (en) | 1999-04-15 |
| EP0568891A1 (en) | 1993-11-10 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| FZDE | Discontinued |