KR20120137481A - Composition for printing a seed layer and process for producing conductor tracks - Google Patents

Abstract

The present invention provides a composition for printing a seed layer for electrodeposition or electroless deposition of metal to create a full-area or structured metal surface on a substrate. The composition may comprise 0.1 to 6% by weight of electrolessly and / or electrolytically coatable particles, 40 to 98.8% by weight of one or more solvents, 0 to 15% by weight of crosslinkers, 0.1 to 6% by weight of one or more dispersing additives, 0 or more additional additives. To 5 weight percent, and 1 to 20 weight percent of one or more polymers, wherein the one or more polymers are in the form of a dispersion. In addition, the present invention provides a process for creating a full or structured metal surface on a substrate. The present invention also provides a method of using the process.

Description

COMPOSITION FOR PRINTING A SEED LAYER AND PROCESS FOR PRODUCING CONDUCTOR TRACKS}

The present invention relates to compositions for printing seed layers for electrodeposition or electroless deposition of metals for the production of full-area or structured metal surfaces on a substrate. In addition, the present invention relates to a process (method) of producing a full-area or structured metal surface on a substrate.

The compositions and processes of the present invention are for example conductor tracks on printed circuit boards, RFID antennas, transponder antennas or other antenna structures, chip card modules, flat cables, sheet heaters, film conductors, conductor tracks on solar cells or LCD or plasma Conductor tracks for visual display units, 3D molded interconnect devices, integrated circuits, resistors, capacitive or inductive elements, diodes, transistors, sensors, actuators, optical components, receiver / transmitter devices, electromagnetic shielding, thermal conduction or It is suitable for producing decorative or functional surfaces, thin film metal foils or single- or double-sidedly laminated polymer supports on products useful as packaging.

In known processes for producing structured or full metal surfaces on a substrate, it is known to first transfer electrically conductive particles present in the matrix material to the substrate, for example. The movement can be carried out by any printing process. US-B 6 177 151 discloses the movement of electrically conductive particles present in the matrix material, for example using a laser printing process. The laser volatilizes the matrix material such that the electrically conductive particles move to the substrate. The electrically conductive particles and the matrix material initially form a solid coating on the support.

However, in addition to the use of laser printing processes, the use of screen printing processes is also common to produce correspondingly structured surfaces. However, a disadvantage of the known processes is that the particles present in the matrix material form a relatively dense surface and the metal layer deposited thereon adheres only to that surface. This can lead to fragmentation of the metal layer, especially in the event of temperature fluctuations. In particular, when the carbon particles are used as particles to be electrolessly and / or electrolytically coated, there is not sufficient adhesion in the processes and compositions known from the prior art for printing layers.

It is therefore an object of the present invention to provide a composition for printing a seed layer for electrodeposition or electroless deposition of a metal for the creation of a full surface or structured metal surface on a substrate that allows stable adhesion of the metal deposited on the substrate. will be.

It is a further object of the present invention to provide a process for producing such a full or structured metal surface on a substrate.

Its purpose is a composition for printing a seed layer for electrodeposition or electroless deposition of metals for the creation of a full-scale or structured metal surface on a substrate, comprising from 0.1 to 6% by weight of electrolessly and / or electrolytically coatable particles, at least one solvent 40 to 98.8 weight percent, 0 to 15 weight percent crosslinker, 0.1 to 6 weight percent of one or more dispersing additives, 0 to 5 weight percent of one or more additional additives, and 1 to 20 weight percent of one or more polymers, The polymer is achieved by the composition being in the form of a dispersion.

The composition of the present invention forms a porous seed layer on the substrate to be coated such that there is a stable adhesion of the metal surface to the seed layer. This may be due in particular to the fact that the metal of the metal surface penetrates into the pores of the seed layer, resulting in mechanical interlinkage between the seed layer and the metal of the metal surface in addition to the chemical adhesion.

In order to obtain very good adhesion between the seed layer and the metal forming the metal surface, it is particularly preferred when the electrolessly and / or electrolytically coatable particles have dimensions which differ in at least one direction from those in the other. As a result of the shape of the electrolessly and / or electrolytically coatable particles, there is no dense filling of the seed layer, instead a cavity is formed between the particles, into which the surface metal can enter. In this way, further improvement of the interconnection between the seed layer and the metal surface is achieved.

The electrolessly and / or electrolytically coatable particles present in the composition are electrically conductive, in particular when using the composition for producing conductor tracks on a printed circuit board. By the electrical conductivity of the electrolessly and / or electrolytically coatable particles, the conductivity of the conductor tracks on the printed circuit board is improved overall over the thin film metal layer deposited on the nonconductive particles.

In a particularly preferred embodiment, the electrolessly and / or electrolytically coatable particles are carbon nanotubes or graphene. The use of carbon nanotubes or graphene creates a structure of seed layers in which individual carbon nanotubes or graphenes are entangled together, thereby forming a kind of fleece structure. The mechanical interconnection of carbon nanotubes or graphene achieves very stable adhesion of the seed layer with the metal on the metal surface.

The proportion of electrolessly and / or electrolytically coatable particles present in the composition is in the range of 0.1 to 6% by weight according to the invention. The proportion of the electrolessly and / or electrolytically coatable particles is preferably in the range of 0.5 to 2% by weight, particularly preferably in the range of 1 to 1.5% by weight.

According to the invention, at least one polymer present in the composition is not soluble in the solvent. Therefore, the polymer is in the form of small particles dispersed in a solvent. Due to the polymer present in the form of small particles in the solvent, drying of the seed layer after application by printing does not result in a uniform layer, but instead results in the formation of pores required for mutual bonding with the metal on the metal surface. Let's do it. Examples of suitable solvents in which one or more polymers are not soluble include water, hydrocarbons such as pentane, hexane, heptane or octane, and esters, ketones, aldehydes, alcohols or glycols, and mixtures thereof. As for the solvent, it is more preferable that it is water.

The proportion of solvent in the composition is in the range of 40 to 98.8% by weight. The proportion of the solvent is preferably in the range from 72 to 93.6% by weight, particularly preferably in the range from 83.5 to 91.4% by weight.

Depending on the solvent used, different polymers may be used that are not soluble in the solvent. The proportion of polymer in the composition is in the range of 1 to 20% by weight, preferably in the range of 4 to 10% by weight, particularly preferably in the range of 5 to 8% by weight.

Examples of suitable polymers include acrylonitrile-butadiene-styrene (ABS); Acrylonitrile-styrene-acrylate (ASA); Acrylated acrylate; Alkyl resins; Alkylvinyl acetates; Alkylene-vinyl acetate copolymers, in particular methylene-vinyl acetate, ethylene-vinyl acetate, butylene-vinyl acetate; Alkylene-vinyl chloride copolymers; Amino resin; Aldehyde and ketone resins; Cellulose and cellulose derivatives, in particular hydroxyalkylcelluloses, cellulose esters such as acetates, propionates, butyrates, carboxyalkylcelluloses, cellulose nitrates; Epoxy acrylate; Epoxy resins; Modified epoxy resins such as bifunctional or polyfunctional bisphenol A or bisphenol F resins, epoxy novolac resins, brominated epoxy resins, cycloaliphatic epoxy resins; Aliphatic epoxy resins, glycidyl ethers, vinyl ethers, ethylene-acrylic acid copolymers; Hydrocarbon resin; Transparent ABS comprising acrylate units (MABS); Melamine resins; Maleic anhydride copolymer; Methacrylate; caoutchouc; Synthetic rubber; Natural resin; rosin; Shellac; Phenolic resin; Polyester; Polyester resins such as phenyl ester resins; Polysulfones; Polyether sulfones; Polyamide; Polyimide; Polyaniline; Polypyrrole; Polybutylene terephthalate (PBT); Polycarbonates (eg Makrolon®, Bayer AG); Polyester acrylate; Polyether acrylate; Polyethylene; Polyethylenethiophene; Polyethylene naphthalene; Polyethylene terephthalate (PET); Polyethylene terephthalate-glycol (PETG); Polypropylene (PP); Polymethylmethacrylate (PMMA); Polyphenylene oxide (PPO); Polystyrene (PS); Polytetrafluoroethylene (PTFE); Polytetrahydrofuran; Polyethers (eg polyethylene glycol, polypropylene glycol), polyvinyl compounds, in particular polyvinyl chloride (PVC), PVC copolymers, polyvinylidene chloride (PVdC), polyvinyl acetate, and copolymers thereof, optionally some Hydrolyzed polyvinyl alcohol, polyvinyl acetal, polyvinyl acetate, polyvinylpyrrolidone, polyvinyl ethers, polyvinyl acrylates and methacrylates as solutions and suspensions and also copolymers, polyacrylic esters and polystyrene copolymers thereof coalescence; Polystyrene (impact modified or impact unmodified); Polyurethanes (PUR), uncrosslinked or isocyanate crosslinked; Polyurethane acrylates; Styrene-acrylic copolymers; Styrene-butadiene block copolymers (eg, Styroflex® and Styrolux®, BASF SE, K-Resin (trade name), CPC); Proteins such as casein; SIS; Triazine resins, bismaleimide-triazine resins (BT), cyanate ester resins (CE), allylated polyphenylene ethers (APPE). It is also possible to use mixtures of two or more polymers.

Particularly preferred polymers are acrylates, cellulose derivatives, methacrylates, methacrylate resins, melamine and amino resins, polyalkylenes, polyimides, epoxy resins, polyurethanes, polyesters, polyvinyl acetals, polyvinyl acetates, polystyrenes, Polystyrene copolymers, polystyrene acrylates, styrene-butadiene block copolymers, alkylene-vinyl acetate and vinyl chloride copolymers, polyamides and copolymers thereof.

Very particularly preferred polymers are polyurethanes and polyacrylates, and copolymers thereof.

Dispersing additives are also present in the compositions to enable storage and processing of the composition over a given period of time without precipitation of the electrolessly and / or electrolytically coatable particles and polymers. The proportion of the dispersing additive is in the range of 0.1 to 6% by weight, preferably in the range of 0.3 to 3% by weight, particularly preferably in the range of 0.5 to 1% by weight.

In principle, all dispersing additives known to those skilled in the art for use in dispersions are suitable. Preferred dispersing additives are surfactants or surfactant mixtures, for example anionic, cationic, amphoteric or nonionic surfactants. Cationic and anionic surfactants are described, for example, in "Encyclopedia of Polymer Science and Technology", J. Wiley & Son (1966), Vol. 5, pages 816-818 and in "Emulsion Polymerization and Emulsion Polymers", editors P. Lovell and M. El-Asser, Wiley & Sons publishers (1997), pages 224-226. However, it is also possible to use polymers which have a pigment affinity fixing group and which are known to those skilled in the art as dispersants.

In addition to the polymer dispersion, it is also possible for a crosslinker to be present in the composition. This improves film properties and affects adhesion, chemical resistance and mechanical strength. The proportion of crosslinker in the dispersion is, for example, in the range from 0 to 15% by weight, preferably in the range from 1.5 to 10% by weight, particularly preferably in the range from 2 to 50% by weight.

Examples of suitable crosslinking agents include (poly) isocyanates, (poly) aziridines, carbodiimides, MF (melamine-formaldehyde) resins, MF crosslinkers, metal complexes and adipic acid bishydrazides. Especially preferred are MF crosslinkers.

In addition to the dispersing additive, it is also possible for further additives to be present in the composition. The proportion of further additives is in the range of 0 to 5% by weight, preferably in the range of 0.1 to 3% by weight, particularly preferably in the range of 0.1 to 1% by weight.

Examples of additives present may be filler components. It may consist of one or more fillers. In practice, the filler component of the composition may comprise fibrous, layered or particulate filler or mixtures thereof. They are preferably commercially available products, for example mineral fillers.

It is also possible to use fillers or reinforcing agents such as glass powder, mineral fibers, whiskers, aluminum hydroxide, metal oxides such as aluminum oxide or iron oxide, mica, quartz powder, calcium carbonate, barium sulfate, titanium dioxide or wollastonite.

Further examples of additives that can be used include thixotropic agents such as silica, silicates such as Aerosil or bentonite, or organic thixotropic agents and thickeners such as polyacrylic acid, polyurethanes, hydrogenated casta oils, dyes, Fatty acids, fatty acid amides, plasticizers, wetting agents, antifoams, lubricants, desiccants, photoinitiators, complexing agents, waxes, pigments or conductive polymer particles.

Additional additives present in the composition may also be processing aids and stabilizers such as UV stabilizers, lubricants, corrosion inhibitors and flame retardants.

The proportions (by mass) of the individual components present in the composition are each based on the total mass of the composition.

The object is also a process for producing a full-area or structured metal surface on a substrate, the following steps:

(a) printing the composition described above on a substrate according to a given pattern,

(b) drying and / or curing the composition to form a seed layer,

(c) electrodepositing and / or electrolessly depositing the metal on the seed layer to apply a metal layer to the composition to produce a full or structured metal surface.

≪ / RTI >

Examples of suitable substrates to which the electrically conductive surface is applied are soft or rigid substrates. It is preferred that the substrate is not electrically conductive. This means that the resistivity is more than 10 ⁹ ohm × cm. Suitable substrates are, for example, reinforced or unreinforced polymers as typically used in printed circuit boards. Suitable polymers include epoxy resins or modified epoxy resins such as bifunctional or multifunctional bisphenol A or bisphenol F resins, epoxy novolac resins, brominated epoxy resins, aramid-reinforced or glass fiber reinforced or paper reinforced epoxy resins (e.g. For example, FR4), glass fiber reinforced polymer, liquid crystal polymer (LCP), polyphenylene sulfide (PPS), polyoxymethylene (POM), polyaryl ether ketone (PAEK), polyether ether ketone (PEEK), polyamide (PA), polycarbonate (PC), polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polyimide (PI), polyimide resin, cyanate ester, bismaleimide-triazine resin, Nylon, Vinyl Ester Resin, Polyester, Polyester Resin, Polyaniline, Phenolic Resin, Polypyrrole, Polyethylene Naphthalate (PEN), Polymethyl Methacrylate, Poly Tylenedioxythiophene, phenolic resin-coated aramid paper, polytetrafluoroethylene (PTFE), melamine resin, silicone resin, fluorine resin, allylated polyphenylylene ether (APPE), polyether imide (PEI), poly Phenylene oxide (PPO), polypropylene (PP), polyethylene (PE), polysulfone (PSU), polyether sulfone (PES), polyarylamide (PAA), polyvinyl chloride (PVC), polystyrene (PS), Among the aforementioned polymers that may be present in acrylonitrile-butadiene-styrene (ABS), acrylonitrile-styrene-acrylate (ASA), styrene-acrylonitrile (SAN), and also in a wide variety of other forms. There is a mixture (blend) of two or more. The substrate may carry additives known to those skilled in the art, for example flame retardants.

In principle, the substrate used may also be any polymer present in the composition and listed above. In addition, other substrates customary in the printed circuit board industry are likewise suitable.

Further suitable substrates include composite materials, foam type polymers, Styropor®, Styrodur®, polyurethane (PU), ceramic surfaces, textiles, paperboard, cardboard, paper, polymer coated paper, wood , Mineral materials, silicon, glass, plant tissues and animal tissues.

In a first step, the composition described above is printed on a substrate according to a given pattern. The composition may be printed on the substrate by any desired printing process known to those skilled in the art. Suitable printing processes include, for example, offset printing processes, laser printing processes, flexographic printing processes, gravure printing processes, screen printing processes, pad printing processes, and inkjet printing processes.

Particular preference is given to printing the composition on the substrate by a screen printing process and a gravure printing process.

After the composition is printed on the substrate, the composition is dried and / or cured to form a seed layer. The composition may be dried and / or cured at ambient temperature under ambient or other conditions. In order to form the seed layer, the composition is preferably dried and / or cured at elevated temperatures. The temperature at which the composition is dried and / or cured is preferably in the range of 30 to 200 ° C, preferably in the range of 50 to 160 ° C, more preferably in the range of 60 to 120 ° C.

In addition to the use of elevated temperatures where the composition dries to form a seed layer, it is also possible to partially cure the composition. Depending on the polymer used and the crosslinker used, the curing may be heat, light, for example UV radiation or visible light, and / or radiation, for example infrared radiation, electron beams, gamma radiation, X-radiation or microwaves. Is achieved by the reaction of. In order to induce the curing reaction, it may be necessary to add a suitable deactivating agent. It is also possible to achieve curing by a combination of different methods, for example by a combination of UV radiation and heat. Combinations of curing processes can be performed simultaneously or sequentially. For example, initially UV radiation can only partially cure the composition to form a seed layer so that the formed structure is not destroyed by free flow. The thermal action can then cure the seed layer. The thermal action can be carried out directly following UV curing and / or electrolytic metallization.

In order to obtain improved adhesion of the composition on the substrate, it is also possible to apply a primer to the substrate before the seed layer is printed on the substrate. In this case, the primer can be applied over the entire substrate. However, the primer is preferably applied when the composition is also applied on the surface of the substrate in the same way as the structure is applied on the surface of the substrate. In this way, the primer is printed on the substrate only at the site where the composition is also printed.

The primer may likewise be applied by a printing process, for example by the same printing process in which the composition is also printed onto the substrate to form a seed layer. However, if the primer is applied over the entire surface, any desired coating process is also possible, such as curtain coating, dipping process or brush application of the primer.

Suitable primers are all systems known to those skilled in the art, which systems must conform to the specific description. Examples are polyurethanes, PVC, (poly) isocyanates, PVA, polyesters, PVBs and copolymers thereof, and mixtures of these types.

Depending on the intended use of the substrate on which the metal surface is provided, it is preferred that the metal applied to the seed layer by electrodeposition and / or electroless deposition is copper, silver, nickel, palladium, platinum, tin or chromium. The thickness of the layer applied by electrodeposition and / or electroless deposition of metal is within the conventional range known to those skilled in the art.

Suitable electrolyte solutions that can be used for the application of metal layers by electrodeposition and / or electroless deposition are known to those skilled in the art and are described, for example, in Werner Jillek, Gustl Keller, Handbuch der Leiterplattentechnik [Hanbook of Printed Circuit] Board Technology, Eugen G. Leuze Verlag, 2003, Vol. 4, pages 332-352.

For electrodeposition and / or electroless deposition of metals on seed layers that produce full or structured metal surfaces, it is possible to use any desired suitable process known to those skilled in the art for electrodeposition or electroless deposition of metals. Do.

The process according to the invention is suitable, for example, for the production of conductor tracks on printed circuit boards. Such printed circuit boards include, for example, those having multiple inner and outer layers, micro-via chips on boards, and soft and rigid printed circuit boards. Such printed circuit boards include, for example, computers, telephones, televisions, electric vehicle components, keyboards, radios, videos, CDs, CD-ROM and DVD players, game consoles, measuring and conditioning equipment, sensors, electric kitchenware, electric toys, and the like. It is incorporated in the product.

The process according to the invention can also produce an electrically conductive structure on a flexible circuit carrier. Such soft circuit carriers are, for example, polymeric films of the materials mentioned above for the substrate, on which an electrically conductive structure is applied. The process according to the invention is also suitable for RFID antennas, transponder antennas or other antenna structures, chip card modules, flat cables, sheet heaters, film conductors, solar cells or conductor tracks, capacitors, film capacitors, resistors in LCD or plasma visual display units. In the manufacture of convectors, electrical fuses, or in electrolytically coated articles which exist in any desired form, for example in the manufacture of single or double side metal laminated polymer carriers with a limited layer thickness, or otherwise. For example, it is suitable for the manufacture of decorative or functional surfaces on products used for electromagnetic radiation shielding, thermal conduction or as packaging.

The process according to the invention can equally manufacture integrated circuits, resistors, capacitors or inductive members, diodes, transistors, sensors, actuators, optical components and receiver / transmitter devices.

In addition, the process is also possible to produce an antenna having contacts for coating and organic electronic components on a surface, which is composed of an electrically nonconductive material for blocking electromagnetic waves.

In addition, the process is available in the sector of flow fields of bipoar plates for fuel cells.

 In addition, the process can be used to produce full or structured electrically conductive layers for subsequent decorative metallization of moldings formed from the aforementioned electrically nonconductive substrates.

The process according to the invention and the field using the compositions of the invention are themselves metallized substrates, in particular switches and sensors, gas barriers or decorative parts, in particular motor vehicles, public toilets, toys, household and office sectors, and also non-conductive It allows for the stable production of metallized substrates for use as packaging and foil / film. The invention can also be used in the field of secure printing for banknotes, credit cards, identification cards and the like. Textiles are electrically and magnetically supported with the aid of the process according to the invention, for example by application of antennas, transmitters, RFID and transponder antennas, heating elements, antistatic systems (or plastics), shields and the like. Can be prepared.

The process is also available for making thin metal foils or single- or double-side stacked polymer carriers or metalized polymer surfaces.

Preferred use of the composition of the invention and the metal surface produced by the composition of the invention is that the product has a printed circuit board, RFID antenna, transponder antenna, seat heater, flat cable, contact free chip card, thin metal foil or single or double Use as side stacked polymer carriers, film conductors, conductor tracks, integrated circuits, resistors, capacitive or inductive members, diodes, transistors, sensors, actuators, optical components, receiver / transmitter devices on solar cells or in LCD or plasma visual display units. Or for decorative use, such as those used in packaging materials.

Claims (10)

A composition for printing a seed layer for electrodeposition or electroless deposition of metal to create a full-area or structured metal surface on a substrate, wherein the electroless and / or electrolytically coatable particles 0.1 to 6 Weight percent, 40 to 98.8 weight percent of one or more solvents, 0 to 15 weight percent of crosslinker, 0.1 to 6 weight percent of one or more dispersing additives, 0 to 5 weight percent of one or more additional additives, and 1 to 20 weight percent of one or more polymers. Wherein said at least one polymer is in the form of a dispersion. The composition of claim 1, wherein the electrolessly and / or electrolytically coatable particles have a dimension that is different in one or more directions than the dimension in the other direction. The composition of claim 1 or 2, wherein the electrolessly and / or electrolytically coatable particles are carbon nanotubes or graphene. The composition of claim 1, wherein the solvent is selected from water, pentane, hexane, heptane, octane, esters, ketones, aldehydes, alcohols, glycols, and mixtures thereof. The composition of claim 1 wherein the polymer is selected from polyurethanes, polyacrylates, and copolymers thereof. A method of producing a full-area or structured metal surface on a substrate, comprising the following steps:
(a) printing a composition according to any one of claims 1 to 5 according to a given pattern on a semiconductor substrate,
(b) drying and / or curing the composition to form a seed layer,
(c) applying a metal layer to the composition by electrodeposition and / or electroless deposition of the metal on the seed layer to form a full or structured metal surface.
≪ / RTI > The method of claim 6, wherein the application of the seed layer by printing proceeds by applying a primer on the substrate. 8. The method of claim 6 or 7, wherein the seed layer is printed on the substrate by a screen printing process. The method of claim 6, wherein the metal is copper, silver, gold, palladium, nickel, chromium or tin. Use of a method according to any of claims 7 to 9 for manufacturing a printed circuit board, RFID antenna or transponder antenna.