Classifications

• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C18/00—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating
  • C23C18/16—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating by reduction or substitution, e.g. electroless plating
  • C23C18/18—Pretreatment of the material to be coated
  • C23C18/20—Pretreatment of the material to be coated of organic surfaces, e.g. resins
  • C23C18/28—Sensitising or activating

Definitions

• the invention relates to membranes modified by a permeable metal layer.
• phase inversion method (compare, for example, Strahtmann, M.) is primarily used to produce “so-called asymmetrical membranes” for reverse osmosis and ultrafiltration.
• polyesters such as polytetrafluoroethylene, polyvinylidene flouride or chloride
• halogen-containing polymers such as polytetrafluoroethylene, polyvinylidene flouride or chloride
• polycarbonate types such as polyimides, polyhydantoins, polyparabanates, polyurethanes, polysulfones, aromatic polyethers, polyethylene and propylene oxides and the like their copolymers, copolymers and graft polymers.
• R retention rate
• the pore diameter is not a fixed size, but rather a size determined via the diameter of the differently sized pores according to a statistical distribution function. For this reason, with the aid of the membrane systems known hitherto, it is not possible to achieve an exact separation of molecules with a small difference in molecular diameter.
• a second parameter for the membrane systems is "the so-called flow rate".
• the selective separation effect generally decreases rapidly as the free channels increase.
• Another important quality characteristic of separation membranes is their chemical and / or thermal resistance.
• the invention is based on the object; to avoid these disadvantages and to modify the chemical or physical properties of known organic membranes so that they enter into a selective chemical and / or physical interaction with the permeant, whereby a sharp separation between molecules with a small difference in molecular weight can be achieved.
• Another object of the invention is to increase its thermal or chemical stability without adversely affecting the original physical properties, such as pore size or pore distribution of the membrane matrix.
• the object is achieved by treating organic polymeric membrane systems with an average pore diameter of 1 to 10,000 nm with the organometallic compounds of Ag, Au, Pt and / or Pd, if necessary sensitizing them in a reducing medium and then in a wet chemical metallization bath with a provides electrically conductive and permeable metal layers of 0.1 - 10 ⁇ m and, if necessary, galvanically reinforces this metal layer.
• organometallic compounds which are very suitable for carrying out the process according to the invention (see, for example, DE-A 3 148 280, 3 150 985 and 3 324 767) are known. These are primarily compounds of precious metals, the organic part of which has a further functional group. Compounds of Pd and Pt are preferred.
• the groups of the organic part of the organometallic compound required for the metal bond are known per se. These are, for example, CC or CN double and triple bonds and groups which can form a chelate complex, for example OH, NH 2 , SH, CO, cs, or COOH.
• Functional groups such as carboxylic acid groups, carboxylic acid halide groups, carboxylic acid anhydride groups, carbonic ester groups, carbonamide and carbonimide groups, aldehyde and ketone groups, ether groups, acid anhydride groups, and sulfonate groups, sulfonic acid halide groups, sulfonic acid ester cyclic groups, halogenated-containing chlorine groups, halogenated groups, , -pyrazinyl, pyrimidinyl or quinoxlinyl groups, activated double bonds, such as in the case of vinylsulfonic acid or acrylic acid derivatives, amino groups, hydroxyl groups, isocyanate groups, olefin groups and acetylene groups, as well as mercapto and epoxy groups, furthermore higher-chain alkyl or alkenyl radicals from C 8 , in particular olein, linole, , Stearin or palmiting groups. 1,3-dienes, ⁇ , ⁇ -
• the adhesive strength can also be brought about by adsorption of the organometallic activators on the substrate surface, the causes of the adsorption being, for example, hydrogen bonds or van der Waalssche forces. / "
• activators with, for example, additional carbonyl or sulfone groups are particularly favorable for metallizing objects based on polyamide or polyester.
• Functional groups such as carboxylic acid groups and carboxylic anhydride groups are particularly suitable for anchoring the activator to the substrate surface by adsorption.
• Another possibility for carrying out the method is the use of host / guest molecules, as described in DE-A 3 424 065.
• the organic part of these compounds is made from cryptands, podands and preferably from cyclic crown ethers of the formula formed (compare, for example, Vögtle, F., “contacts” (Darmstadt) (1977) and (1978), Weber, E., “contacts” (Darmstadt) (1984) and Vögtle, F., Chemikerzeitung, 97, p. 600 -610 (1973)).
• Precious metal compounds to be used with preference are those having the formula
• PdCl 4 Na 2 (PdCl 2 Br 2 ), Na 2 PdCl 4 , CaPdCl 4 , Na 4 (PtCl 6 ), AgNO 3 , HAuCl 4 , and AuCl 3 .
• the Pd compounds are preferred.
• Suitable colloidal noble metal systems are derived above all from the metals Pd, Pt, Au and Ag and are, for example, in "plastic electroplating” by R. Weiner, Eugen G. Leuze Verlag, Saulgau / Württ. (1973), pages 180-209.
• the electrically neutral ligand takes up the cation M n + in its endohydrophilic cavity at the phase boundary and transports it into the organic solvent phase, whereby the E m + Hal - z part also enters the desired solvent phase due to the potential gradient is also transported.
• this phenomenon is also relevant for the systems listed in points 2), 3) and 4).
• the activation solution can be prepared by dissolving the said organometallic compounds in protic or aprotic solvents in amounts of 0.01-1 g / 1, preferably 0.1-2.5, particularly preferably 0.1-1.0 g / l.
• organic solvents are polar, protic and aprotic solvents such as methylene chloride, chloroform, 1,1,1-trichloroethane, trichlorethylene, perchlorethylene, acetone, methyl ethyl ketone, butanol, ethylene glycol, tetrahydrofuran, methanol and ethanol.
• polar, protic and aprotic solvents such as methylene chloride, chloroform, 1,1,1-trichloroethane, trichlorethylene, perchlorethylene, acetone, methyl ethyl ketone, butanol, ethylene glycol, tetrahydrofuran, methanol and ethanol.
• the samples are optionally treated in a reducing medium.
• the reduction is preferably carried out in aqueous solution.
• solvents such as alcohols, ethers, hydrocarbons can also be used.
• suspensions or slurries of the reducing agents can also be used.
• the surfaces treated in this way can be used directly for electroless metallization. However, it may also be necessary to rinse the surfaces of the reducing agent residues.
• This embodiment is particularly suitable for nickel baths containing aminoborane or copper baths containing formalin.
• Metallization baths which can be used in the process according to the invention are preferably baths with nickel salts, cobalt salts, copper salts, gold and silver salts or mixtures thereof with one another or with iron salts.
• Such metallization baths are known in the electroless metallization art and preferably contain hypophosphites and boranes as reducing agents.
• the average layer thickness of the metal layer can be 0.01 - 10 ⁇ m. Those with a layer thickness of 0.01-5.0 ⁇ m are particularly preferred and those with a layer thickness of 0.1-1.0 ⁇ m are particularly preferred.
• Ni, Co and Cu layers deposited with the preferred baths contain either 0.75-7% by weight B or 0.75-10% by weight P depending on the reducing agent.
• organic porous membranes can be provided with the said systems with a permeable but thermally and electrically conductive or flexible metal coating. It is also surprising that the metal coating assumes the geometry of the membrane and the pore structure of the membrane matrix is completely preserved. This effect can be observed most strongly with host-guest complex ligands and then metallized membrane systems. It should also be mentioned that these systems can be heated by applying the electrical current. With the help of this effect, both better separation efficiency and higher flow rates are achieved.
• organometallic compounds based on Pt, Pd, Au, Ag, Cu, Co and Ni are suitable for this. However, those based on Pd and Pt are particularly preferred. Of course, the said organometallic compounds can only be used for doping membranes.
• the permeable metal layers deposited by the method according to the invention are good heat and electrical conductors, which leads to a considerable increase in thermal stability by avoiding selective accumulation of heat build-up.
• the membranes suitable for carrying out the method according to the invention can have an average diameter of 1 to 10,000 nm, particularly those with 1 to 5,000 nm or those with 1 to 1,000 nm, the mean values of which are in the range of 10 to 500 nm are prefer.
• membranes based on organic natural or synthetic polymers are suitable as substrates for the process according to the invention.
• cellulose ester types such as cellulose di- or triacetates (see, for example, DE 26 21 519 or US 31 33 132), polyamides (see, for example, DE 19 41 932), polyureas such as Polyhydantoins and polyparabanates (see, for example, DE 24 31 071) polysulfones, polyethers, polyesters, polyether polypropylene oxides, halogen-containing polymers such as Teflon and Tedlar are particularly suitable.
• these membranes can also be fixed on porous carrier tiles based on polyethylene, polypropylene, polyester or polyamide.
• membrane substrates which contain organic or inorganic fillers and are suitable for carrying out the process have been described several times in the literature (see, for example, DE 21 29 014, DE 21 40 310, EP 77 509).
• Multi-layer membranes produced by the process according to the invention are for separating reactive gases such as NH 3 , 0 2 , CO, NO, N0 2 , H 2 S, C1 2 and F 2 ; Inert gases such as He, N 2 , A 2 and liquid gases such as butadiene 1,2- and 1,4-, C0 2 from gas mixtures or for the purification of liquids containing anion, cation and / or neutral particles are well suited.
• Another preferred application of the membrane according to the invention is the separation of ionogenic or colloidal substances such as cations or anions in the electrical field.
• the metallized membrane is switched to separate cations as cathode or to separate anions as anode.
• the current density A required for this can be varied widely between 0.001 A / dm 2 up to the critical decomposition voltage of the respective media to be separated.
• Preferred current densities are in the range of 0.01-2.0 A / dm 2 .
• test strips consist, for example, of a transparent plastic carrier and a porous and / or permeable membrane layer.
• the matrix of the membrane overlay contains specific detection reagents which, by reaction with the analyte to be determined according to the substance concentration, different color intensities (color gradations).
• the polyurethane dispersion serves as a coagulation aid and is a cationic, emulsifier-free dispersion of a reaction product
• This casting solution is used to uniformly coat a polyethylene terephthalate film with a doctor knife in a drawing thickness of 100 ⁇ m.
• This carrier-supported film is coagulated in a 30% aqueous glycerol bath which additionally contains 1% by weight Na lauryl sulfate.
• the resulting solid, support-etched membrane is dried with warm air.
• a permeable membrane system with a pore diameter distribution of 30-1000 nm is obtained, the average pore size being 500 nm.
• a 10 x 10 cm square of the above membrane is activated at RT (room temperature) for 90 seconds in an activation bath which is prepared from 0.25 g of mesityl oxide palladium chloride and 1 liter of tetrachlorethylene, dried at RT and then in an aqueous nickel-plating bath for 15 minutes , which in 1 liter contains 33 g NiS0 4 6H 2 0, 11.5 g citric acid, 18.5 ml 2n DMAB (dimethylamine borane) solution, 2.5 g boric acid and is adjusted to pH 5 with a 25% ammonia solution, electroless nickel-plated. After about 45 seconds the substrate surface begins to turn gray and after about 12 minutes the specimen was covered with an electrically conductive 0.5 ⁇ m thick Ni coating with 2% boron content.
• RT room temperature
• the scanning electron micrographs (SEM) of the system described show that, surprisingly, it is a porous metal layer, its mean pore size being identical to the porous polymer layer.
• Test strips were soaked for 1 minute in a 1Xigen peroxidase (POD, 277 U / mg) / glucose oxidase (116 U / mg) solution in citrate buffer (pH 5.5) and dried. 0.25% by weight glucose solution was added to the membrane surface. The amount of glucose sorbed can then be detected potentiometrically.
• POD 1Xigen peroxidase
• glucose oxidase 116 U / mg
• the casting solution is applied with a doctor blade to a glass plate (100 ml) and immersed in an aqueous 10% glycerol bath for coagulation. This removes the film from the glass support and you get a support-free, asymmetrical membrane.
• test specimen A 150 x 300 mm rectangle of the above The test specimen is immersed in a solution of 0.52 g of 3-hepten-2-one-palladium chloride in 500 ml of acetone for 30 seconds, dried at room temperature and then coppered for 20 minutes in a reductive copper bath from Shipley AG, Stuttgart.
• the solution is then mixed with 10 ml of DMF.
• the membrane is produced by knife coating on glass plates using a coating device for thin-layer chromatography. After evaporation of the solvent, the membrane film is activated in an activation solution consisting of 0.5 g of 1,4-butadiene palladium dichloride and 1 l of methanol for 30 seconds, in a reduction solution consisting of Sensitized for 5 minutes, washed with distilled water and then nickel-plated in a commercially available hypophosphite-containing nickel plating bath from Blasberg AG, Solingen. After about 12 minutes, the test specimen was covered with a 0.15 ⁇ m thick phosphorus-containing nickel layer (7.2% P).
• the above-mentioned metallized membrane system is switched as a cathode in a conventional reverse osmosis analysis at 0.7 amp / dm 2 .
• the permeation studies show that the said membrane system is very suitable for separating cations such as Na + , K + , Ca 2+ , Mg 2+ and Cr 3+ from aqueous solutions.
• a commercially available porous membrane (average pore size 5 ⁇ m) is activated according to Example 3, sensitized, chemically provided with a 0.15 ⁇ m thick Cu coating according to Example 2 and then the Cu coating in a commercially available galvanic Cu bath from Fa Schering AG, Berlin, reinforced to 3.5 ⁇ m. You get a highly permeable membrane system. The pores of the metal layer are almost identical to those of the polymer membrane.
• An aromatic copolyamide was prepared from 3- (aminophenyl) -7-amino-2,4- (1H, 3H) -quinazolinedione, 3,3-diaminodiphenyl disulfimide and isophthalic acid (cf.
• the casting solution is applied to a carrier fleece made of polyethylene with a thickness of 100 ⁇ m. After drying for about 2 minutes at various temperatures, the film is precipitated in a water bath, then immersed in a 30% glycerol bath and then dried at 50 ° C. (from EP 0 077 509 A1).
• a 10 ⁇ 10 cm square of the above membrane is activated at RT for 90 seconds in an activation solution consisting of 0.7 g of 4-cyclohexene-1,2-dicarboxylic acid anhydride and 500 ml of CH 2 Cl 2 and nickel-plated according to Example 1 for 30 seconds.
• the said membrane system which is heated to 80 ° C. by external application of the electric current (6 volts), phenols and aromatic amines, for example, can be successfully separated from aqueous systems.
• polyhydantoin with the general formula (A) are dissolved in 90 g of a mixture of N-methylpyrrolidone and dimethylacetamide (1: 1) and mixed with 1.6 g of lithium chloride.
• the blue solution is filtered through a pressure filter and left to stand until it is free of bubbles.
• a part of this solution is drawn with a mechanical film slide on a glass plate to a film with a thickness of 200 microns and then dried on a hot plate with vigorous nitrogen flow at 60 ° C for 10 minutes. After cooling for 10 minutes at RT, the film with the glass plate is immersed in an ice bath and kept there for 1/2 hour.
• This co-coating is reinforced to 1.9 ⁇ m in a commercially available galvanic Pt bath from Degussa AG.
• This membrane system can be heated to 120 ° C. by applying an electrical current (for example 4 volts) and can thus be used excellently for separating H 2 from H 2 / N 2 .

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• 1986
  • 1986-05-10 DE DE19863615831 patent/DE3615831A1/de not_active Withdrawn
• 1987
  • 1987-04-27 EP EP87106081A patent/EP0245684A3/fr not_active Withdrawn
  • 1987-05-07 JP JP62109920A patent/JPS62274075A/ja active Pending
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