Classifications

• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
  • C09J115/00—Adhesives based on rubber derivatives
  • C09J115/02—Rubber derivatives containing halogen
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08C—TREATMENT OR CHEMICAL MODIFICATION OF RUBBERS
  • C08C19/00—Chemical modification of rubber
  • C08C19/12—Incorporating halogen atoms into the molecule
  • C08C19/18—Incorporating halogen atoms into the molecule by reaction with hydrocarbons substituted by halogen
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
  • C09J151/00—Adhesives based on graft polymers in which the grafted component is obtained by reactions only involving carbon-to-carbon unsaturated bonds; Adhesives based on derivatives of such polymers
  • C09J151/04—Adhesives based on graft polymers in which the grafted component is obtained by reactions only involving carbon-to-carbon unsaturated bonds; Adhesives based on derivatives of such polymers grafted on to rubbers
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L2666/00—Composition of polymers characterized by a further compound in the blend, being organic macromolecular compounds, natural resins, waxes or and bituminous materials, non-macromolecular organic substances, inorganic substances or characterized by their function in the composition
  • C08L2666/02—Organic macromolecular compounds, natural resins, waxes or and bituminous materials
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L2666/00—Composition of polymers characterized by a further compound in the blend, being organic macromolecular compounds, natural resins, waxes or and bituminous materials, non-macromolecular organic substances, inorganic substances or characterized by their function in the composition
  • C08L2666/28—Non-macromolecular organic substances

Definitions

• the present invention relates to compositions of matter which are useful for bonding substrates or surfaces of various materials. More specifically, the present invention relates to an environmentally acceptable adhesive composition which is capable of withstanding high temperatures and which contains, inter alia, a Diels-Alder adduct and a phenolic resin.
• injection mold bonding is effective since production can be increased due to the use of higher cure temperatures and shorter cure times and since the rubber/metal bonding process can be automated.
• injection molding processes are carried out at high temperatures (320° - 350° F) which can interfere with the bonding effectiveness of the adhesive composition utilized in the process.
• the pre-cured rubber will not mix with the rest of the rubber in the mold, resulting in the formation of weak boundary layers that can lead to premature failure in the cured article.
• These adhesives are also somewhat disadvantageous in that they typically require the application of two coats of material, such as a primer and an overcoat, in order to obtain sufficient adhesion.
• a one-coat adhesive composition is needed that will utilize non-toxic, environmentally acceptable components as well as withstand increasingly demanding bonding conditions such as those experienced during injection molding processes. Such an adhesive composition should also produce an adhesive bond that will resist exposure to adverse environments such as high temperature fluids and corrosive agents. Disclosure of Invention
• the present invention is a one-coat adhesive composition which predominantly utilizes environmentally acceptable components and which can withstand elevated temperature bonding conditions.
• An adhesive bond prepared with the present adhesive composition also exhibits excellent resistance to high temperature fluid environments and corrosive conditions.
• the present adhesive composition contains a Diels-Alder adduct of a perhalogenated cyclic conjugated diene and an olef-nically unsaturated dienophile having a vinyl content in excess of 50 percent, a phenolic resin, an aromatic hydroxy compound, a formaldehyde donor, a heat-activated unsaturated elastomer crosslinker, a vulcanizing agent and a metal oxide.
• the Diels-Alder adduct of the present invention is preferably formed by reacting at least one halogenated cyclic conjugated diene and at least one polyalkadiene dienophile having a high vinyl content.
• the vinyl content is the proportion of polydiene units bounded together in the 1,2-mode of addition to form pendant vinyl groups and is quantitatively determined by infrared absorption spectroscopy at 11.0 microns, using a solution of approximately 2.5 grams of polymer in 100 milliliters of anhydrous carbon disulf ⁇ de.
• the Diels-Alder adducts preferably have a halogen content in the range from about 20 to 40, and the range of about 26 to 35 weight percent based on the total weight of adduct material is particularly preferred.
• the polyalkadiene of the Diels-Alder adduct is more particularly characterized by a vinyl content of at least 50 percent, preferably of at least 70 percent, and most preferably is in the range from 88 to 98 percent, based on total olefinic unsaturation.
• halogenated cyclic conjugated dienes which are employed in forming the adducts for use in this invention have the formula
• X is a halogen selected from the group consisting of chlorine, bromine and fluorine, with chlorine being currently preferred and n being 1, 2 or 3, preferably 1.
• the halogenated cyclic dienes are readily prepared by well-known methods and at least one, hexachlorocyclopentadiene, is a well-known article of commerce.
• Other representative dienes include hexafluorocyclopentadiene, hexabromocyclopentadiene, 5,5-difluorotetra-chlorocyclopentadiene and 5,5-dibromotetrachlorocyclopentadiene.
• Hexachlorocyclo ⁇ pentadiene is presently preferred for use in the present invention.
• the polyalkadiene dienophiles which are reacted with the halogenated cyclic conjugated dienes to form the adducts which are employed in the adhesive compositions of this invention are, as noted, characterized by a vinyl content of at least 50 percent.
• the dienophiles are further characterized by having an elongated backbone carbon chain which is characterized by the presence of a predominant amount of pendant non-terminal vinyl groups attached to alternating carbon atoms of the backbone of the polyalkadiene to provide the structure
• m is a measure of the degree of polymerization and is typically an integer between 10 and 4,000.
• the vinyl groups constitute at least 50 percent, preferably 70 to 98 percent and especially 88 to 98 percent, of the residual olefinic unsaturation of the dienophile.
• the polyalkadiene dienophiles are further characterized by having molecular weights in the range from 500 to 200,000, preferably 10,000 to 120,000 and most preferably 35,000 to 120,000.
• the polyalkadiene dienophiles which can be employed in the practice of this invention include liquid polymers and solid gum polymers.
• polyalkadiene materials which are suitable for use in forming the adhesive compositions described herein are polymeric materials selected from the group consisting of polyalkadienes, hydroxyl-terminated polyalkadienes, chain-extended hydroxyl- terminated polyalkadienes, carboxyl-terminated polyalkadienes, chain-extended carboxyl-terminated polyalkadienes, mercaptan- terminated polyalkadienes, chain-extended mercaptan-terminated polyalkadienes, amine-terminated polyalkadienes, chain- extended amine-terminated polyalkadienes, and their equivalents.
• polyalkadiene is understood to refer to polymers of at least one conjugated diene having from 4 to 12 carbon atoms and includes copolymers of at least one such conjugated diene and at least one other monomer copolymerizable therewith.
• the polyalkadienes can be unmodified, e.g., polybutadiene, random copolymers of poly(butadiene-styrene), and the like; or modified, as by having hydroxyl or carboxyl termination and including chain-extended hydroxyl-terminated and carboxyl- terminated polymeric materials.
• the polyalkadienes can also be the block copolymers of styrene and butadiene as disclosed in co-pending Application Serial No. 07/657,929 filed February 20, 1991, entitled "Adhesive Compositions Based on Block Copolymer Adducts," which is incorporated herein by reference.
• the polyalkadienes can be either liquid polymers or solid gum polymers.
• the hydroxyl-substituted, carboxyl-substituted, amine-substituted and mercaptan-substituted polyalkadienes as produced by the majority of the present commercial polymerization processes generally are liquid polymers having molecular weights in the range of about 500 to about 20,000; with the bulk of such substituted polyalkadienes having molecular weights in the range of about 750 to about 3,000.
• the hydroxyl-, carboxyl-, amine- and mercaptan-substituted polyalkadienes will normally be chain- extended in order to increase their molecular weights to the ranges found most suitable in the present invention.
• Especially preferred dienophiles are 1,2-polybutadiene homopolymers having a vinyl content in excess of 90 percent, a molecular weight between 35,000 and 40,000 and a crystallinity between 23 and 27 percent.
• a description of the preparation of 1,2-polybutadiene homopolymers can be found in the Encyclopedia of Polymer Science and Technology. Vol. 2, John Wiley and Sons, New York, 1985, p. 573.
• hydroxyl-substituted, carboxyl-substituted, amine- substituted, and mercaptan-substituted polyalkadiene dienophiles can be readily modified to the desired molecular weight range by conventional chain extension techniques, as by contacting the polyalkadiene prepolymer with a polyfunctional organic chain extender with thorough mixing, desirably followed by degassing. Chain extending reaction conditions are well-known in the art and will not be discussed here in great detail.
• the chain extension of a dihydroxy polyalkadiene prepolymer with a diisocyanate chain-extender such as 2,4-toluene diisocyanate is effected at room temperature or at a moderately elevated temperatures.
• the reaction conditions are a function of the materials employed and these conditions can be readily determined by one skilled in the art.
• the resulting chain-extended polyalkadiene has a substantially increased molecular weight range and, in physical appearance, can be a highly- viscous fluid or solid gum.
• a full description of the chain extension of reactive substituted polyalkadiene dienophiles, including representative chain extending compounds, is found in Polaski U.S. Patent No. 3,894,982, particularly from Col. 5, line 16 through Col. 8, line 51, which disclosure is incorporated herein by reference.
• the adducts which are used in the practice of the invention are readily prepared by conventional techniques well known in the field of Diels-Alder reactions.
• the Diels-Alder adduction between the halogenated cyclic diene and the high vinyl dienophiles is effected in an organic solvent such as xylene in relative amounts such that the stoichiometric ratio between the halogenated cyclic conjugated diene and the double bonds of the dienophile is in the range of 0.01 to 1.
• the mixture is heated at temperatures in the range from 100° C to 200° C. Within this temperature range, the adduction reaction is exothermic and yields are quite often quantitative.
• the reaction is continued for a time sufficient to substantially react the halogenated cyclic conjugated diene and the high vinyl dienophile to provide an adduct having a halogen content in the range from about 20 to 40, preferably about 26 to 35, percent by weight based on the total weight of the adduct.
• the halogen content of the adduct can be determined by known analytical procedures, such as Schoniger combustion.
• the Diels-Alder adducts of the present invention are also described in detail in U.S. Patent No. 4,795,778 which is incorporated herein by reference.
• the Diels-Alder adduct of the present invention is typically utilized in an amount ranging from about 35 to 75, preferably from about 45 to 65, percent by dry weight (excluding solvent) of the total adhesive composition.
• the phenolic resin of the present invention can essentially be any heat-reactive phenolic resin.
• Typical phenolic resins include the organic solvent-soluble heat-reactive condensation product of an aldehyde having from 1 to 8 carbon atoms, such as formaldehyde, acetaldehyde, isobutyraldehyde, ethylhexaldehyde, and the like, with phenolic compounds such as phenol, o-cresol, m-cresol, p-cresol, mixed cresols, e.g., cresylic acid and m-cresol and/or p-cresol, xylenol, diphenylolproprane, p-butyl-phenol, p-phenylphenol, p- chlorophenol, o-chlorophenol, m-bromophenol, 2-ethylphenol, p- alkoxyphenol, nonyl phenol, p-tert-amylphenol,
• the phenolic resin will preferably be formed in a conventional manner from the condensation of from about 0.8 to about 5 moles of aldehyde per mole of phenolic compound in the presence of basic, neutral, or acidic catalysts to afford an organic solvent-soluble resin having a molecular weight in the range of from about 300 to about 2,000, preferably from about 300 to about 1,200.
• a particularly preferred phenolic resin is prepared by reacting formaldehyde and phenol to create a phenol formaldehyde resin having a methylol content ranging from about 10 to 60, preferably about 30 to 50 percent.
• the phenolic resin is typically employed in an amount ranging from about 1 to 15, preferably about 3 to 8, percent by dry weight of the adhesive composition.
• the aromatic hydroxy compound of the present invention can be essentially any aromatic compound having one, two or three hydroxy substituents.
• the aromatic compound is preferably benzene, and the other non-hydroxy substituents on the benzene ring or other aromatic compound may be hydrogen, alkyl, aryl, alkylaryl, arylalkyl carboxy, alkoxy, amide, imide, halogen or the like.
• the non-hydroxy substituents are most preferably hydrogen and, if alkyl, are preferably lower alkyls having from one to 10 carbon atoms including methyl, ethyl, propyl, amyl, and nonyl.
• Representative monohydroxy compounds include phenol, p-t-butyl phenol, p-phenylphenol, p-chloro-phenol, p-alkoxyphenol, o-cresol, m-cresol, o-chlorophenol, m-bromo-phenol, 2-ethylphenol, amyl phenol, and nonyl phenol, with phenol, p-t-butyl phenol and nonyl phenol being preferred monohydroxy aromatic compounds.
• Representative dihydroxy compounds include resorcinol, hydro quinone and catechol with resorcinol being the preferred dihydroxy aromatic compound.
• trihydroxy compounds include pyrogallol, gallates such as propyl gallate, robinetin, baptigenin and anthragallol, with pyrogallol being the preferred trihydroxy aromatic compound. It is presently preferred to utilize resorcinol as the aromatic hydroxy compound of the invention.
• the aromatic hydroxy compound is typically utilized in the invention in an amount ranging from about 1 to 15, preferably from about 7 to 11, percent by dry weight of the adhesive composition.
• the formaldehyde donor of the invention can essentially be any type of formaldehyde or formaldehyde source known to react with hydroxy aromatic compounds to form phenolic resins.
• Typical compounds useful as a formaldehyde donor in the present invention include formaldehyde and aqueous solutions of formaldehyde, such as formalin; acetaldehyde; propionaldehyde; isobutyraldehyde; 2- ethylbutyraldehyde; 2-methylpentaldehyde; 2-ethylhexaldehyde; benzaldehyde; as well as compounds which decompose to formaldehyde, such as paraformaldehyde, trioxane, furfural, hexamethylenetetramine; acetals which liberate formaldehyde on heating; and the like. It is presently preferred to utilize hexamethylenetetramine as the formaldehyde donor of the invention.
• the heat-activated unsaturated elastomer crosslinker of the present invention can be any of the commonly known crosslinkers, such as quinone dioxime, dibenzoquinone dioxime, and 1,2,4,5- tetrachlorobenzoquinone.
• the crosslinker is typically employed in an amount ranging from about 0.1 to 15, preferably 1 to 4, percent by dry weight of the adhesive composition.
• the vulcanizing agent of the present invention can be any known vulcanizing agent which is capable of crosslinking elastomers at molding temperatures (140° - 200° C).
• Preferred vulcanizing agents for use in the invention are selenium, sulphur, and tellurium, especially selenium.
• the vulcanizing agent is utilized in the present invention in an amount ranging from about 1 to 15, preferably from about 2 to 7, percent by dry weight of the adhesive composition.
• the metal oxide can be any known metal oxide such as zinc oxide, magnesium oxide, litharge, red lead, dibasic lead phosphite, and combinations thereof, with zinc oxide being the preferred metal oxide since it is unusually effective and environmentally more acceptable than the lead-containing alternatives.
• the metal oxide is typically utilized in an amount ranging from about 1 to 60, preferably fro about 10 to 20, percent by dry weight of the adhesive composition.
• the present adhesive composition can optionally contain other well-known additives including plasticizers, fillers, pigments, reinforcing agents and the like, in amounts employed by those skilled in the adhesive arts to obtain the desired color and consistency.
• Typical additional additives include fumed silica, carbon black, and titanium dioxide. It is particularly preferred in the present invention to use fumed silica and carbon black in order to pigment, reinforce, and control the rheology of the adhesive.
• the fumed silica is typically employed in an amount ranging from about 0.5 to 5, preferably about 1 to 3, percent by dry weight of the total adhesive composition, while the carbon black is typically employed in an amount ranging from about 3 to 50, preferably about 8 to 15, percent by dry weight of the total adhesive composition.
• Typical solvents useful in the invention include aromatic hydrocarbons such as xylene, toluene, and polar solvents such as ketones, including methylisobutyl ketone, and methyl ethyl ketone.
• the solvent is typically utilized in an amount sufficient to create an adhesive formulation having a viscosity in the range from 25 to 5000, preferably 100 to 700, centipoises at a total solids content (TSC) in the range from about 5 to 40, preferably about 10 to 35, percent.
• TSC total solids content
• the present adhesive composition may also be prepared as an aqueous formulation by adding typical aqueous surfactants such as aryl alkyl ethoxylates, adding water under high shear conditions to form the emulsion, and vacuum stripping the solvent as is known in tiie art.
• the adhesive composition of the invention is preferably utilized to bond an elastomeric material to a metal surface under heat and pressure.
• the composition may be applied to the metal surface by spraying, dipping, brushing, wiping, or the like, after which the 5 composition is allowed to dry.
• the coated metal surface and the elastomeric substrate are typically brought together under a pressure of from about 20.7 to 172.4 Mega Pascals (MPa), preferably from about 20 MPa to 50 MPa.
• the resulting rubber-metal assembly is simultaneously heated to a temperature from about 140° C to about
• the assembly should remain under the applied pressure and temperature for a period of from about 3 minutes to 60 minutes, depending on the cure rate and thickness of the rubber substrate. This process may be carried out by applying the rubber substrate as a semi-molten material to the metal
• the adhesive compositions of the present invention are particularly suitable for use in injection molding processes.
• the process may also be carried out by utilizing compression molding, transfer molding or autoclave curing techniques. After the process is 0 complete, the bond is fully vulcanized and ready for use in a final application.
• the adhesives of the present invention are preferred for bonding elastomeric materials to metal
• the present adhesive compositions may be applied as an adhesive, primer or coating to any 5 surface or substrate capable of receiving the adhesive.
• the material which may be bonded to a surface such as a metal surface in accordance with the present invention, is preferably a polymeric material, including any elastomeric material selected from any of the natural rubbers and olefinic synthetic rubbers including 0 polychloroprene, polybutadiene, neoprene, Buna-S, Buna-N, butyl rubber, brominated butyl rubber, nitrile rubber, and the like.
• the material is preferably natural rubber, or styrene-butadiene rubber.
• the surface to which the material is bonded can be any surface such as a glass, plastic or fabric surface capable of receiving the adhesive 5 and is preferably a metal surface selected from any of the common structural metals such as iron, steel (including stainless steel), lead, aluminum, copper, brass, bronze, Monel metal, nickel, zinc, and the like.
• An adduct of hexachlorocyclopentadiene and 1,2-polybutadiene is prepared by reacting 79.8 gms of hexachlorocyclopentadiene, 201.5 gms of 1,2-polybutadiene (vinyl content 92%, crystallinity 25%, MW 95,000), and 718.7 gms of xylene at 142° C for 20 hours. This yields an adduct containing between 27 and 29 percent chlorine. The adduct is then precipitated into methanol, dried, and redissolved in a 2/1 methylisobutyl ketone/xylene blend three times to remove unreacted hexachlorocyclopentadiene.
• Phenol formaldehyde resin (37% methylol content, 70% TSC in 3:1 methylethyl ketone:ethanol solvent).
• the adhesive compositions prepared above in Examples 1 and 2 are coated onto grit-blasted steel coupons at a film thickness of 0.5 to 1.2 mils.
• the coated coupons are bonded to E-218 (55-60 durometer Shore A semi-EV cure natural rubber), HC-202 (60-65 durometer Shore A styrene butadiene rubber), and A060P (40-45 durometer Shore A natural rubber) substrates by injection molding the rubber onto the coated coupons at 330° F, and then vulcanizing the rubber at 330° F for
• Bonded parts are pulled to destruction according to ASTM test method D429B. Parts are tested in peel with a peel angle of 45 degrees. The test is conducted at room temperature with a test speed of 20 inches per minute. After the bonded part fails, the peak peel strength value (measured in pounds) and the percent rubber retention on the adhesive coated area of the part are measured.
• Bonded parts are buffed on the edges with a grinding wheel.
• the rubber is then tied back over the metal with stainless steel wire. This exposes the bondline to the environment. Failure is initiated by scoring the bondline with a razor blade.
• the parts are then strung on stainless steel wire and placed in a salt spray chamber.
• the environment inside the chamber is 100° F, 100 percent relative humidity, and 5 percent dissolved salt in the spray, which is dispersed throughout the chamber. The parts remain in this environment for 72 hours.
• the rubber is peeled from the metal with pliers. The percent rubber retention on the part is then measured.
• Bonded parts are prepared the same way as they are for the salt spray test; however, in this test, the parts are placed in a beaker filled with boiling tap water. The parts remain in this environment for 2 hours. Upon removal, the rubber is peeled from the metal with pliers. The percent rubber retention on the part is then measured.
• Bonded parts are prepared the same way as they are for the salt spray test.
• the parts are placed in a can filled with a solution containing 70 percent (by weight) ethylene glycol and 30 percent water.
• the can containing the parts is then heated to 300° F for 100 hours.
• the rubber is peeled from the metal with pliers. The percent rubber retention on the part is then measured.
• Bonded parts are prepared the same way as they are for the salt spray test. In this test, the parts are placed in a beaker filled with tap water which is at room temperature. The parts remain in this environment for seven days. Upon removal, the rubber is peeled from the metal with pliers. The percent rubber retention on the part is then measured.
• the predominately non- toxic adhesive compositions of the present invention can be applied as a one-coat system which will withstand the demanding bonding conditions of an injection molding process. Furthermore, the adhesive bond so produced is capable of resisting high temperature fluids (ethylene glycol/water) and corrosive agents (salt spray).
• high temperature fluids ethylene glycol/water
• salt spray corrosive agents

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Health & Medical Sciences (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Adhesives Or Adhesive Processes (AREA)
• Compositions Of Macromolecular Compounds (AREA)
• Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)

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• 1991
  • 1991-04-10 US US07/683,219 patent/US5128403A/en not_active Expired - Lifetime
• 1992
  • 1992-03-25 EP EP19920302572 patent/EP0508650A3/en active Pending
  • 1992-03-25 CZ CS932089A patent/CZ208993A3/cs unknown
  • 1992-03-25 WO PCT/US1992/002400 patent/WO1992018566A1/en not_active Ceased
  • 1992-03-25 EP EP92909532A patent/EP0582623A1/en active Pending
  • 1992-03-25 RO RO94-00320A patent/RO112361B1/ro unknown
  • 1992-03-25 HU HU9302846A patent/HUT65893A/hu unknown
  • 1992-03-25 CA CA002107101A patent/CA2107101C/en not_active Expired - Fee Related
  • 1992-03-25 RU RU93058138A patent/RU2120454C1/ru active
  • 1992-03-25 SK SK1089-93A patent/SK283624B6/sk unknown
  • 1992-03-25 JP JP4509593A patent/JP2784610B2/ja not_active Expired - Fee Related
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  • 1992-04-09 IE IE113992A patent/IE921139A1/en unknown
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  • 1992-04-10 CN CN92102610A patent/CN1051105C/zh not_active Expired - Fee Related
• 1993
  • 1993-11-08 BG BG98204A patent/BG61309B1/bg unknown

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