Classifications

• • 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—Ethylene-propylene or ethylene-propylene-diene copolymers
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L19/00—Compositions of rubbers not provided for in groups C08L7/00 - C08L17/00
  • C08L19/003—Precrosslinked rubber; Scrap rubber; Used vulcanised rubber
• • 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
  • 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 atoms other than carbon or hydrogen
  • C08L23/0853—Ethylene vinyl acetate copolymers
• • 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
  • C08K5/00—Use of organic ingredients
  • C08K5/01—Hydrocarbons
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L31/00—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an acyloxy radical of a saturated carboxylic acid, of carbonic acid or of a haloformic acid; Compositions of derivatives of such polymers
  • C08L31/02—Homopolymers or copolymers of esters of monocarboxylic acids
  • C08L31/04—Homopolymers or copolymers of vinyl acetate

Definitions

• the invention is in the field of recycling used vulcanised t natural and synthetic rubber, more in particular in the field of recycling vulcanised, ground tire rubber, profiles, production waste and post consumer waste, to produce polymer blends having useful properties.
• compositions may have a wide variety of physical and mechanical properties such as useful hardness, values, ozone resistance, and the ability to process the material on conventional rubber processing equipment. More in particular there is a need for re-use of ground rubber scrap in applications, wherein the scrap replaces virgin rubber, while maintaining the properties of the original virgin rubber.
• 'virgin rubber' is intended to indicate rubber that has not yet undergone a vulcanisation or other crosslinking treatment.
• the term 'rubber' is used in the conventional sense of a polymeric substance having a glass transition temperature well below -35°C, as defined in ASTM D3418.
• the present invention is accordingly directed to a rubber composition
• a rubber composition comprising an amount of 5 to 70 parts by weight of vulcanised, ground rubber scrap, an amount of 1 to 30 parts by weight of a combination of at least one EPDM rubber and at least one EVA copolymer, the EPDM rubber and the EVA copolymer having undergone a partial condensation reaction with an ethylene copolymer having short chain branching an amount of 20 to 95 parts by weight of virgin rubber .
• such a rubber composition comprising on the one hand ground rubber scrap and on the other hand the reaction product of EPDM and EVA provides a superior quality rubber composition having properties that may range from thermoplastic rubbers to vulcanisable rubbers.
• such a rubber composition comprises 10 - 40 parts by weight of vulcanised, ground rubber scrap, 15 - 45 wt . % of the condensation product of EPDM rubber and EVA copolymer and 20 to 75 parts by weight of virgin rubber.
• the rubber composition comprises additionally an amount of from 1 to 20 parts by weight of oil, preferably a paraffinic oil.
• At least one EPDM rubber should be present in the composition of the present invention .
• This rubber is based on ethylene, propylene and at least one diene monomer, such as those conventionally used. Examples are dicyclopentadiene, hexadiene, ethylidene-norbornene and the like. It is preferred to use an EPDM that has a Mooney viscosity ML (1+4) at 125°C between 8 and 60.
• the copolymer of ethylene and vinylacetate the copolymer of ethylene and vinylacetate
• at least one ethylene vinylacetate copolymer having a vinylacetate content of between 25 and 40 wt . % is used.
• a combination of at least 2 EVA copolymers is being used, one having a vinylacetate content between 25 and 40 wt . % , whereas the other one has a vinylacetate content between 10 and 20 wt . % .
• the relative amounts of the two products are preferably between 1 : 2 to 2 :1.
• the invention requires that part of the EPDM and part of the EVA have undergone a chemical reaction.
• the reaction conditions disclosed in the cited US patents can be used.
• the condensation product has undergone a reaction with an ethylene polymer having short chain branching.
• This polymer is suitably a linear low density polyethylene, based on ethylene and at least one C 4 to C 8 copolymer.
• the amount of the copolymer ranges between 5 and 40 wt . % calculated on the weight of EPDM, EVA and the copolymer together.
• vulcanised, ground rubber scrap such as ground tire rubber (GTR) , which forms the largest amount of the rubber to be recycled.
• vulcanised natural or synthetic rubbers such as vulcanised SBR, vulcanised blends of natural rubber and SBR, and vulcanised EPDM, BAN, butyl, chlorobutyl or chloroprene rubber.
• the vulcanised rubber is comminuted, preferably grinded, preferably under cryogenic conditions until a particle size preferably between 0.05 and 1.0 mm, preferably between 0.05 and 0.5 mm has been obtained. It is to be noted that GTR usually does not contain substantial amounts of fibres or steel from the tires.
• the amounts of the condensation product and the grinded rubber scrap are related.
• the amount of scrap is at most 5 time the amount of the condensation product, taking into account the particle size of the scrap, finer particles requiring higher amounts of condensation product .
• a preferred component of the polymer composition according to the invention is an oil component, such as a paraffinic oil. This oil is preferably a regular paraffinic oil that is used for extending rubbers.
• the product of the invention further contains an amount of virgin rubber, preferably of the same or comparable type as the scrap.
• Virgin rubbers suitable are both natural and synthetic rubbers, or blends of two or more types of rubber.
• synthetic rubbers one may use nitril rubber, SBR, EPDM rubber, butadiene rubber, butyl rubber, chlorinates polyethylene (CPE) , neoprene rubber, polyisoprene, and the like.
• the composition can be processed into conventional rubber compositions, having the same properties as those based on virgin rubbers, using the same or comparable recipes as those valid for virgin materials.
• the recipes can be used as such, just replacing the virgin material by the combination of the scrap and the condensation product .
• the amounts of rubber that may be replaced vary in dependence of the type of final product. For thermoplastic rubber compositions this may be up to 70 wt . % of the total composition, whereas for vulcanisable materials this may be up to 40 wt . % .
• the recipe may be changed, such as the type of vulcanisation (or not) , amount of oil, fillers and the like.
• the rubber composition according to the invention can be used as such, as a thermoplastic elastomer.
• Those products may be used in the conventional manner just as the regular virgin products would be used. This means that the rubbers may for example be filled with carbon and other conventional components. It is also possible to vulcanise the rubber composition of the invention.
• a blend was prepared from 50 wt . % grinded tire scrap, based on a vulcanised blend of NBR and SBR, 10 wt . % oil (OBI 10) and 40 wt . % of the reaction product of 47.5 wt . % of an EVA copolymer having 28 wt . % vinylacetate, 47.5 wt . % EPDM and 5 wt . % of LLDPE, as described in Example 5 of US patent specification No. 4,877,827.
• Compression set 22 hr at 21 °C % 35 36 Compression set, 22 hr at 23 °C % 32 Compression set, 22 hr at 50 °C % 76 Compression set, 22 hr at 70 °C % 97 59 97 Compression set, 22 hr at 100 °C % 106

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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)
• Compositions Of Macromolecular Compounds (AREA)

Priority Applications (1)

Applications Claiming Priority (4)

Publications (1)

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• 1999
  • 1999-11-08 CA CA002350719A patent/CA2350719A1/en not_active Abandoned
  • 1999-11-08 AU AU11902/00A patent/AU1190200A/en not_active Abandoned
  • 1999-11-08 EP EP99971825A patent/EP1124897A1/de not_active Withdrawn
  • 1999-11-08 WO PCT/NL1999/000683 patent/WO2000027915A1/en not_active Ceased

Non-Patent Citations (1)

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