CA1090023A - Separating agent for rubber powders - Google Patents
Separating agent for rubber powdersInfo
- Publication number
- CA1090023A CA1090023A CA281,805A CA281805A CA1090023A CA 1090023 A CA1090023 A CA 1090023A CA 281805 A CA281805 A CA 281805A CA 1090023 A CA1090023 A CA 1090023A
- Authority
- CA
- Canada
- Prior art keywords
- rubber
- separating agent
- powder
- polyacrylonitrile
- mixture according
- 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.)
- Expired
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L21/00—Compositions of unspecified rubbers
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J3/00—Processes of treating or compounding macromolecular substances
- C08J3/12—Powdering or granulating
- C08J3/124—Treatment for improving the free-flowing characteristics
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L11/00—Compositions of homopolymers or copolymers of chloroprene
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
- C08L23/02—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
- C08L23/04—Homopolymers or copolymers of ethene
- C08L23/08—Copolymers of ethene
- C08L23/0846—Copolymers of ethene with unsaturated hydrocarbons containing other atoms than carbon or hydrogen atoms
- C08L23/0853—Vinylacetate
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
- C08L23/02—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
- C08L23/16—Elastomeric ethene-propene or ethene-propene-diene copolymers, e.g. EPR and EPDM rubbers
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L9/00—Compositions of homopolymers or copolymers of conjugated diene hydrocarbons
- C08L9/02—Copolymers with acrylonitrile
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L9/00—Compositions of homopolymers or copolymers of conjugated diene hydrocarbons
- C08L9/06—Copolymers with styrene
- C08L9/08—Latex
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L33/00—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides or nitriles thereof; Compositions of derivatives of such polymers
- C08L33/18—Homopolymers or copolymers of nitriles
- C08L33/20—Homopolymers or copolymers of acrylonitrile
Landscapes
- Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- Compositions Of Macromolecular Compounds (AREA)
- Processes Of Treating Macromolecular Substances (AREA)
Abstract
Abstract of the Disclosure A freeflowing rubber mixture which is stable against coalescence and cohesion comprising a vulcanisable rubber in powder form and a minor amount of an acrylonitrile polymer as a separating agent.
Description
ios~
It i~ known that rubber powder3 can be produced by spray-drying a latex or by grinding ~olid rubber. In either ca~e, the fluidity o~ the rubber powder, once it has been produced, h~s to be ]kept i~tact by the Presence of separating agents which prevent coalescence and cohesion.
The quantity in which the separating agent is added is, of cour~e, dependent upon the taokines~ oi the rubber ~nd upon the eP~ectiveness o~ the additive. Thus, the ~pray drying of a latex in the presence o~ at least 10 % by weight of diatomaceous earth i~ described in US Patent Speciiicatio~s Nos. 2,315,924 and 3,194,781. In addition to heterogeneous additive~, powder-~orm rubber~ of the type in que~tion also contain considerable quantitieR o~ emulsi~iers arising ~rom their production which are potentially detrimental to the propertie~ of the materials produced ~rom the rubber. The relatively high degree of swelling whioh vulcanisate~ ~uch as the~e undergo in water i5 mentioned as an ex~mple.
According to British Patent Speci~ication No. 1,079,976, a rubber powder i9 obtained by using a poly~acch~ride, especially starch~ and an inorganic additive, especially talcum. In addition, US Patent Speciiication~ No9.
1,215,918; 1,204,405 and 1,148,348 and Briti~h Patent Speci~ication No. 1,113,348 de~cribe prooe~es ~or the production oi powder-~orm rubber which, through anti-sticking agents added to the latex in certain precipitation ~ - 2 - ar : ' . . . ' ~ . .', . , : .
.
. . . .
IL~)9~Z3 and working-up processes, are sAid to produce the pOwaer-form rubberl precipit~ted i~ powder or granular iorm, in that condition.
Another possible method ~ producing powder-~orm rubber is to ~tart with the solution polymer. In thi~
method, which i~ described in DT-OS No. 2,214,121, more or le~ large quantities o~ eillers and emul~i~iere are added during the process which is terminated by a precipitation ~tep.
In addition, solid rubber h~s already been ground below its glas~ temperature ior the production o~ rubber powder (Journal o~ Applied Science, 10 (1966), p~ge~ 955 959)-In the above-mentioned processes) which generally start with the late~ of an emulsion or solution polymsr9 mare or less het~x~e~eous a ~ tives are w~rked into the r~bber, ior e~mple by spray drying. Unfortunately~ the relatively large quantities oi additives required for maintaining a high degree oi ~luidity aiXect the character of the rubber and its processing a~d vulcani~ation properties.
All conventional methods ior the production oi rubber powder require relatively large quantities of heterogeneous additives so that inter alia the choice of the s~ating agents i9 oi critical ~igni~icance eo far a~ the i'urther -proceesing oi the powders i~ concerned. In particular, inorganic lubricant powders alter certaln raw material propertie~ such as by producing high a~h level~, but above Le ~ I7 170 3 ar .,, ~ . : .
109~Z~
all - especially in case~ where the powder-form rubber i8 ~urther processed in solution (~or esumple rOr producing adhesives~ - becau~le they are insoluble or swellable in solvents and precipitate ~rom the ~olutions.
Or~c separating agents ~ ~so have the disadvantage that they adversely a~fect the vulcanisnte values o~
elastom0rs in regard to their resistance to ~welling in water and in industrial oils and also in machine and engine oils, or they are dissolved by the corresponding medium and contaminate it, so that ~econdary damage can be caused. Another disadvantage of the separating agent described in the literature is, ior e~ample, the ~a¢t that they are not heat-re~istant and either ~often or give off aggre~ive substances or are destroyed by atmospheric oxygen. For example, the addition o~ polyvlnyl chloride as a separating agent for powd ~ form nitrile n~r has long bee~ known and is used on a commercial scale ior the production of powder-i'orm rubber~. Uniortunately, the addition o~ PVC limit~ the use$ul~ess o~ an elastomer.
The properties of ethylene-vinyl acetate copolymer~ or even heat-stabilised acrylonitrile-butadiene rubber vulcanisates would be greatly aifected by the ~ddition of PVC ~nd their range of industrial application~ ~would be ~everely reetricted.
It ha~ now been iound that polyacrylonitr~le (PAN) is a suitable separating agent in ~any respects. Polyacrylonitrile has the adv~ntage from the commerci.al point o~ view that }~O - 4 - ar .
.
.. `'~' ' ~' `"".' .` ' ' .~L0900Z;~
as an organic substance it is obtained during polymerisation in such a fine particle size of from 5 to 150~ that it may be directly used without any need for further size reduction. A
polyacrylonitrile powder having a grain size distribution of from 10 to 80~ is particularly suitable.
The present invention relates to a freeflowing rubber mixture which is stable against coalescence and cohesion com-prising a vulcanisable rubber in powder form having a grain size of from 1 to 3000~ and from 3 to 12~ by weight, based on the rubber, of polyacrylonitrile having a particle size from 5 to 150~.
The polyacrylonitrile unexpectedly has an excellent effect as separating agent. In addition to this, it is heat-resistant and behaves favourably in contact with liquid media.
It does not dissolve or swell in apolar or substantially apolar liquids such as, for example, industrial oils, so that it may be used in elastomers of the type employed for the production of adhesives. Completely clear or clouded solutions are obtained, according to the polarity of the solvent used. The separating agent is swollen and shows no tendency towards sedimentation in these solutions. ;
This applies in particular to so-called special elastomers, such as nitrile rubber, ethylene-vinyl acetate elastomers and other elastomers, such as polychloroprene for example, which are only soluble in polar solvents.
Unexpectedly, the separating agent is also highly effective in apolar elastomers such as polybutadiene and styrenebutadiene rubber with high cold flow, so that powderform rubbers with extremely good free-flow properties are obtained.
. - .~:.
.
~9(1~0Z;~
B According to the present invention any_ ~ d-or synthetic rubber may be stabilized against coalescence and cohesion. Suitable synthetic rubbers are homo- or copolymers of conjugated dienes having from 4 to 8 carbon atoms and of the corresponding monomers wherein one or more of the hydrogen atoms have been replaced by halogen atoms. Examples for such monomers are butadiene, isoprene, dimethyl butadiene, 2-chloro-butadiene (chloroprene) and 2,3-dichloro butadiene. Likewlse suitable are copolymers of these monomers with vinyl aromatic compounds like styrene andd~methyl styrene, acrylonitrlle and methacrylonitrile. Other suitable synthetic rubbers are ethylene propylene terpolymers and copolymers of ethylene with vinyl esters of C2-C20-alkane carboxylic acids. Polychloro-prene and copolymers of ethylene with vinyl acetate, butadiene with styrene and butadiene with acrylonitrlle are preferred.
In the rubber mixtures according to the present invention the rubber particles have a grain size of from 1 to 3000 /u preferably from 5 to 1600 /u.
Unexpectedly, the vulcanisation rate is also unaffected by PAN. It may even be increased and not decreased as is the case with some inorganic separating agents.
Another advantage of polyacrylonitrile as a separating agent is above all the fact that the addition of PAN produces hardly any changes in the properties, especially the Mooney viscosities, of the raw materials.
The separating agent may be worked into the rubber, for example during a grinding process, by precipitation processes or during spray drying. It is generally added in a quantity of from 3 to 12 ~ by weight and preferably in a quantity of from 3 to 7 ~ by weight, based on the weight of rubber.
Le A 17 170 - 6 . .
' '", . :' ' , ,' . ~ , :
9~ 3 When the polyacrylonitrile was added in conjunction with other separating agents, for example zinc or calcium salts of fatty acids, it was not possible to observe any adverse effects upon the maint:enance of fluidity. ~n cases such as these, the quantity i~l which the separating agent according to the invention is added may frequently be reduced.
Further additives which may be present in an amount of from 3 to 12 % by weight, based on rubber, in the rubber mixtures according to the present invention are reparating agents, fillers and other additives known in the art, for example metal oxides like siliciumdioxide, titanium dioxide and magnesium oxide; carbon black; talcum, diatomaceous earth, kaolin, silicic acid and salts of stearic acid like zinc stearate and calcium stearate.
An ethylene-vinyl acetate copolymer with ~ vinyl acetate content of 45 ~ by weight and a Mooney viscosity oi 22 ME wae ground in the preeence oi 4 ~ by weight oi' polyacrylo~itrile (P~N, p~rticle 9ize 10 - 80 ~U) in an industrial 45 kilowatt ba~ile-plate impact mill. The rubber powder obt~ined had a pack etrength (determined in ~ccordance with A5TM-D 1937-62 T) oi 30 lb~. ~he material showed excellent ~luldlty whlch it ret~ined ~or ~ever~l ~onthe.
Grain ei~e d~etributlon o~ the 0 - 0.5 mm = 21 rubber powder: 0.5 - 1 mm = 41 1 - 1.5 mm ~ 38 Le A 17 170 - 7 -_ _ , ~0~q~023 The physicAl propertiee of a peroxidlcally croe~linked vulcani~ate prod~ced irom the rubber powder were sub~tantially unchanged in comparison with a vulc~ni~at0 oi tha ~tarting material. ~here was no evidence oi any impairment to the pero~idic cro~linking process.
A slightly olouded rubber solution was obtained in toluene, but no sediment wa~ produced, even art0r prolonged standing.
E~AMPLE 2 ~ . ~. . ~
A butadiene-acrylonitrile rubber with an ACN-content of 28 % by weight and a Mooney viscosity of 59 ME was ground in the pre~ence o~ 5 % by weight o~ PAN in the ~ame way a~ described i~ E~ample 1.
A pack strength (determined in aocordance with ASTM-D 1937-62 T) o~ more th~n 50 lbs was mea~ured ior a grain ~i~e di~tribution oi the completed powder-~orm rubber of: 25 % les~ than 0.5 mm 50 ~ ~rom 0,5 - 1 mm 25 ~ ~rom 1 - 1.6 mm A ~ree-flowing rubber powder with extremely good iluidity was obtained. The vulcani~ate value~ of the rubber mi~tures produced irom thi~ powder were satisiactory.
~ .
Styrene-butadiene rubber (SRR 1500) with a Mooney vi~co~ity oi 51 ME was ground in the presence oi 7 ~ by weight o~ PAN in the ~ame way as de~cribed in E3ample 1.
A pack strength (ASTM D 1937-62 ~) oi more than 3D lbs was obtained.
The vulcanisate propertie~ o~ the test specimens produced ~rom this rubber powder were satid~actory.
Le A 17 170 - 8 -~ v :,. ' ' ' . ' ; .'~ ','.. ,' ' ;, '.. , . :
. . . . .................... . . . .
,, . .. .. : ,. ... .. . .
The gr~n size distributio:n of the rubber powder was as iollows: 24.5 96 up to 0.5 mm 36.5 oh ~rom 0.5 - 1 m~
49.0 ~ ~rom 1 - 1.5 mm A iree-flowing rubber powder with extremely good fluidity wa~ obtained.
E~MPLE 4 A polymer of 2-chlorobutadiene with a Mooney vi~co~lty (according to DIN 53 523) ML 4 (100C) o~ 81 wae ground in the prese~ce oi 5 ~ by weight oi polyacrylonltrile in the same way a~ de~cribed in Example 1. A iree-~lowing rubber powder with a pack strength oi more than 3D lb~
was obtained.
Le A 17 170 _ 9 _
It i~ known that rubber powder3 can be produced by spray-drying a latex or by grinding ~olid rubber. In either ca~e, the fluidity o~ the rubber powder, once it has been produced, h~s to be ]kept i~tact by the Presence of separating agents which prevent coalescence and cohesion.
The quantity in which the separating agent is added is, of cour~e, dependent upon the taokines~ oi the rubber ~nd upon the eP~ectiveness o~ the additive. Thus, the ~pray drying of a latex in the presence o~ at least 10 % by weight of diatomaceous earth i~ described in US Patent Speciiicatio~s Nos. 2,315,924 and 3,194,781. In addition to heterogeneous additive~, powder-~orm rubber~ of the type in que~tion also contain considerable quantitieR o~ emulsi~iers arising ~rom their production which are potentially detrimental to the propertie~ of the materials produced ~rom the rubber. The relatively high degree of swelling whioh vulcanisate~ ~uch as the~e undergo in water i5 mentioned as an ex~mple.
According to British Patent Speci~ication No. 1,079,976, a rubber powder i9 obtained by using a poly~acch~ride, especially starch~ and an inorganic additive, especially talcum. In addition, US Patent Speciiication~ No9.
1,215,918; 1,204,405 and 1,148,348 and Briti~h Patent Speci~ication No. 1,113,348 de~cribe prooe~es ~or the production oi powder-~orm rubber which, through anti-sticking agents added to the latex in certain precipitation ~ - 2 - ar : ' . . . ' ~ . .', . , : .
.
. . . .
IL~)9~Z3 and working-up processes, are sAid to produce the pOwaer-form rubberl precipit~ted i~ powder or granular iorm, in that condition.
Another possible method ~ producing powder-~orm rubber is to ~tart with the solution polymer. In thi~
method, which i~ described in DT-OS No. 2,214,121, more or le~ large quantities o~ eillers and emul~i~iere are added during the process which is terminated by a precipitation ~tep.
In addition, solid rubber h~s already been ground below its glas~ temperature ior the production o~ rubber powder (Journal o~ Applied Science, 10 (1966), p~ge~ 955 959)-In the above-mentioned processes) which generally start with the late~ of an emulsion or solution polymsr9 mare or less het~x~e~eous a ~ tives are w~rked into the r~bber, ior e~mple by spray drying. Unfortunately~ the relatively large quantities oi additives required for maintaining a high degree oi ~luidity aiXect the character of the rubber and its processing a~d vulcani~ation properties.
All conventional methods ior the production oi rubber powder require relatively large quantities of heterogeneous additives so that inter alia the choice of the s~ating agents i9 oi critical ~igni~icance eo far a~ the i'urther -proceesing oi the powders i~ concerned. In particular, inorganic lubricant powders alter certaln raw material propertie~ such as by producing high a~h level~, but above Le ~ I7 170 3 ar .,, ~ . : .
109~Z~
all - especially in case~ where the powder-form rubber i8 ~urther processed in solution (~or esumple rOr producing adhesives~ - becau~le they are insoluble or swellable in solvents and precipitate ~rom the ~olutions.
Or~c separating agents ~ ~so have the disadvantage that they adversely a~fect the vulcanisnte values o~
elastom0rs in regard to their resistance to ~welling in water and in industrial oils and also in machine and engine oils, or they are dissolved by the corresponding medium and contaminate it, so that ~econdary damage can be caused. Another disadvantage of the separating agent described in the literature is, ior e~ample, the ~a¢t that they are not heat-re~istant and either ~often or give off aggre~ive substances or are destroyed by atmospheric oxygen. For example, the addition o~ polyvlnyl chloride as a separating agent for powd ~ form nitrile n~r has long bee~ known and is used on a commercial scale ior the production of powder-i'orm rubber~. Uniortunately, the addition o~ PVC limit~ the use$ul~ess o~ an elastomer.
The properties of ethylene-vinyl acetate copolymer~ or even heat-stabilised acrylonitrile-butadiene rubber vulcanisates would be greatly aifected by the ~ddition of PVC ~nd their range of industrial application~ ~would be ~everely reetricted.
It ha~ now been iound that polyacrylonitr~le (PAN) is a suitable separating agent in ~any respects. Polyacrylonitrile has the adv~ntage from the commerci.al point o~ view that }~O - 4 - ar .
.
.. `'~' ' ~' `"".' .` ' ' .~L0900Z;~
as an organic substance it is obtained during polymerisation in such a fine particle size of from 5 to 150~ that it may be directly used without any need for further size reduction. A
polyacrylonitrile powder having a grain size distribution of from 10 to 80~ is particularly suitable.
The present invention relates to a freeflowing rubber mixture which is stable against coalescence and cohesion com-prising a vulcanisable rubber in powder form having a grain size of from 1 to 3000~ and from 3 to 12~ by weight, based on the rubber, of polyacrylonitrile having a particle size from 5 to 150~.
The polyacrylonitrile unexpectedly has an excellent effect as separating agent. In addition to this, it is heat-resistant and behaves favourably in contact with liquid media.
It does not dissolve or swell in apolar or substantially apolar liquids such as, for example, industrial oils, so that it may be used in elastomers of the type employed for the production of adhesives. Completely clear or clouded solutions are obtained, according to the polarity of the solvent used. The separating agent is swollen and shows no tendency towards sedimentation in these solutions. ;
This applies in particular to so-called special elastomers, such as nitrile rubber, ethylene-vinyl acetate elastomers and other elastomers, such as polychloroprene for example, which are only soluble in polar solvents.
Unexpectedly, the separating agent is also highly effective in apolar elastomers such as polybutadiene and styrenebutadiene rubber with high cold flow, so that powderform rubbers with extremely good free-flow properties are obtained.
. - .~:.
.
~9(1~0Z;~
B According to the present invention any_ ~ d-or synthetic rubber may be stabilized against coalescence and cohesion. Suitable synthetic rubbers are homo- or copolymers of conjugated dienes having from 4 to 8 carbon atoms and of the corresponding monomers wherein one or more of the hydrogen atoms have been replaced by halogen atoms. Examples for such monomers are butadiene, isoprene, dimethyl butadiene, 2-chloro-butadiene (chloroprene) and 2,3-dichloro butadiene. Likewlse suitable are copolymers of these monomers with vinyl aromatic compounds like styrene andd~methyl styrene, acrylonitrlle and methacrylonitrile. Other suitable synthetic rubbers are ethylene propylene terpolymers and copolymers of ethylene with vinyl esters of C2-C20-alkane carboxylic acids. Polychloro-prene and copolymers of ethylene with vinyl acetate, butadiene with styrene and butadiene with acrylonitrlle are preferred.
In the rubber mixtures according to the present invention the rubber particles have a grain size of from 1 to 3000 /u preferably from 5 to 1600 /u.
Unexpectedly, the vulcanisation rate is also unaffected by PAN. It may even be increased and not decreased as is the case with some inorganic separating agents.
Another advantage of polyacrylonitrile as a separating agent is above all the fact that the addition of PAN produces hardly any changes in the properties, especially the Mooney viscosities, of the raw materials.
The separating agent may be worked into the rubber, for example during a grinding process, by precipitation processes or during spray drying. It is generally added in a quantity of from 3 to 12 ~ by weight and preferably in a quantity of from 3 to 7 ~ by weight, based on the weight of rubber.
Le A 17 170 - 6 . .
' '", . :' ' , ,' . ~ , :
9~ 3 When the polyacrylonitrile was added in conjunction with other separating agents, for example zinc or calcium salts of fatty acids, it was not possible to observe any adverse effects upon the maint:enance of fluidity. ~n cases such as these, the quantity i~l which the separating agent according to the invention is added may frequently be reduced.
Further additives which may be present in an amount of from 3 to 12 % by weight, based on rubber, in the rubber mixtures according to the present invention are reparating agents, fillers and other additives known in the art, for example metal oxides like siliciumdioxide, titanium dioxide and magnesium oxide; carbon black; talcum, diatomaceous earth, kaolin, silicic acid and salts of stearic acid like zinc stearate and calcium stearate.
An ethylene-vinyl acetate copolymer with ~ vinyl acetate content of 45 ~ by weight and a Mooney viscosity oi 22 ME wae ground in the preeence oi 4 ~ by weight oi' polyacrylo~itrile (P~N, p~rticle 9ize 10 - 80 ~U) in an industrial 45 kilowatt ba~ile-plate impact mill. The rubber powder obt~ined had a pack etrength (determined in ~ccordance with A5TM-D 1937-62 T) oi 30 lb~. ~he material showed excellent ~luldlty whlch it ret~ined ~or ~ever~l ~onthe.
Grain ei~e d~etributlon o~ the 0 - 0.5 mm = 21 rubber powder: 0.5 - 1 mm = 41 1 - 1.5 mm ~ 38 Le A 17 170 - 7 -_ _ , ~0~q~023 The physicAl propertiee of a peroxidlcally croe~linked vulcani~ate prod~ced irom the rubber powder were sub~tantially unchanged in comparison with a vulc~ni~at0 oi tha ~tarting material. ~here was no evidence oi any impairment to the pero~idic cro~linking process.
A slightly olouded rubber solution was obtained in toluene, but no sediment wa~ produced, even art0r prolonged standing.
E~AMPLE 2 ~ . ~. . ~
A butadiene-acrylonitrile rubber with an ACN-content of 28 % by weight and a Mooney viscosity of 59 ME was ground in the pre~ence o~ 5 % by weight o~ PAN in the ~ame way a~ described i~ E~ample 1.
A pack strength (determined in aocordance with ASTM-D 1937-62 T) o~ more th~n 50 lbs was mea~ured ior a grain ~i~e di~tribution oi the completed powder-~orm rubber of: 25 % les~ than 0.5 mm 50 ~ ~rom 0,5 - 1 mm 25 ~ ~rom 1 - 1.6 mm A ~ree-flowing rubber powder with extremely good iluidity was obtained. The vulcani~ate value~ of the rubber mi~tures produced irom thi~ powder were satisiactory.
~ .
Styrene-butadiene rubber (SRR 1500) with a Mooney vi~co~ity oi 51 ME was ground in the presence oi 7 ~ by weight o~ PAN in the ~ame way as de~cribed in E3ample 1.
A pack strength (ASTM D 1937-62 ~) oi more than 3D lbs was obtained.
The vulcanisate propertie~ o~ the test specimens produced ~rom this rubber powder were satid~actory.
Le A 17 170 - 8 -~ v :,. ' ' ' . ' ; .'~ ','.. ,' ' ;, '.. , . :
. . . . .................... . . . .
,, . .. .. : ,. ... .. . .
The gr~n size distributio:n of the rubber powder was as iollows: 24.5 96 up to 0.5 mm 36.5 oh ~rom 0.5 - 1 m~
49.0 ~ ~rom 1 - 1.5 mm A iree-flowing rubber powder with extremely good fluidity wa~ obtained.
E~MPLE 4 A polymer of 2-chlorobutadiene with a Mooney vi~co~lty (according to DIN 53 523) ML 4 (100C) o~ 81 wae ground in the prese~ce oi 5 ~ by weight oi polyacrylonltrile in the same way a~ de~cribed in Example 1. A iree-~lowing rubber powder with a pack strength oi more than 3D lb~
was obtained.
Le A 17 170 _ 9 _
Claims (7)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A freeflowing rubber mixture which is stable against coalescence and cohesion comprising a vulcanisable rubber in powder form having a grain size of from 1 to 3000µ and from 3 to 12% by weight, based on the rubber, of polyacrylonitrile having a particle size from 5 to 150µ, .
2. A rubber mixture according to claim 1 containing 3 to 7% by weight of the polyacrylonitrile.
3. A rubber mixture according to claim 1 wherein the polyacrylonitrile has a particle size of from 10 to 80µ.
4. A rubber mixture according to claim 1, wherein the rubber is polychloroprene, a copolymer of ethylene and vinyl-acetate or a copolymer of butadiene and styrene or acrylo-nitrile.
5. A rubber mixture according to claim 1, 2, or 3 wherein the rubber particles have a grain size of from 5 to 1600µ.
6. A rubber mixture according to claim 4 wherein the rubber particles have a grain size of from 5 to 1600µ.
7. A rubber mixture according to claim 6 wherein the polyacrylonitrile has a particle size from 10 to 80µ.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP2629705.2 | 1976-07-02 | ||
| DE19762629705 DE2629705A1 (en) | 1976-07-02 | 1976-07-02 | RELEASE AGENT FOR RUBBER POWDER |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1090023A true CA1090023A (en) | 1980-11-18 |
Family
ID=5982009
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA281,805A Expired CA1090023A (en) | 1976-07-02 | 1977-06-30 | Separating agent for rubber powders |
Country Status (8)
| Country | Link |
|---|---|
| JP (1) | JPS535243A (en) |
| BE (1) | BE856245A (en) |
| CA (1) | CA1090023A (en) |
| DE (1) | DE2629705A1 (en) |
| ES (1) | ES460272A1 (en) |
| FR (1) | FR2356692A1 (en) |
| GB (1) | GB1523850A (en) |
| NL (1) | NL7707291A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107466301B (en) * | 2015-04-13 | 2020-05-29 | 阿朗新科德国有限责任公司 | Pulverulent mixture containing low-emission nitrile rubber |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE1570124B2 (en) * | 1965-09-11 | 1973-04-05 | Lehmann & Voss & Co, 2000 Hamburg | INHIBITION OF ANVULCANIZATION OF CHLOROPRENE HOMO- OR COOPOLYMERIZATES |
| FR1534717A (en) * | 1967-02-27 | 1968-08-02 | Pechiney Saint Gobain | Process for obtaining rubbery polymers having no tendency to agglomeration |
| FR2084006A5 (en) * | 1970-03-04 | 1971-12-17 | Exxon Research Engineering Co | |
| US3839503A (en) * | 1972-10-10 | 1974-10-01 | Phillips Petroleum Co | Process for preparing blends of finely particulate polyacrylonitrile and high vinyl polybutadiene |
-
1976
- 1976-07-02 DE DE19762629705 patent/DE2629705A1/en not_active Withdrawn
-
1977
- 1977-06-29 BE BE178884A patent/BE856245A/en unknown
- 1977-06-30 CA CA281,805A patent/CA1090023A/en not_active Expired
- 1977-06-30 ES ES460272A patent/ES460272A1/en not_active Expired
- 1977-06-30 NL NL7707291A patent/NL7707291A/en not_active Application Discontinuation
- 1977-06-30 GB GB2739977A patent/GB1523850A/en not_active Expired
- 1977-06-30 JP JP7727177A patent/JPS535243A/en active Pending
- 1977-07-01 FR FR7720385A patent/FR2356692A1/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| GB1523850A (en) | 1978-09-06 |
| BE856245A (en) | 1977-12-29 |
| FR2356692A1 (en) | 1978-01-27 |
| FR2356692B1 (en) | 1982-06-18 |
| JPS535243A (en) | 1978-01-18 |
| NL7707291A (en) | 1978-01-04 |
| ES460272A1 (en) | 1979-05-01 |
| DE2629705A1 (en) | 1978-01-05 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |