Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/08—Processes
  • C08G18/0804—Manufacture of polymers containing ionic or ionogenic groups
  • C08G18/0819—Manufacture of polymers containing ionic or ionogenic groups containing anionic or anionogenic groups
• • 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
  • C08J7/00—Chemical treatment or coating of shaped articles made of macromolecular substances
  • C08J7/04—Coating
  • C08J7/0427—Coating with only one layer of a composition containing a polymer binder
• • 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
  • C08J7/00—Chemical treatment or coating of shaped articles made of macromolecular substances
  • C08J7/04—Coating
  • C08J7/043—Improving the adhesiveness of the coatings per se, e.g. forming primers
• • 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
  • C08J7/00—Chemical treatment or coating of shaped articles made of macromolecular substances
  • C08J7/04—Coating
  • C08J7/044—Forming conductive coatings; Forming coatings having anti-static properties
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D175/00—Coating compositions based on polyureas or polyurethanes; Coating compositions based on derivatives of such polymers
  • C09D175/04—Polyurethanes
• • 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
  • C08J2475/00—Characterised by the use of polyureas or polyurethanes; Derivatives of such polymers
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L2201/00—Properties
  • C08L2201/04—Antistatic

Definitions

• the invention relates to aqueous coating compositions based on polyols, in particular for coating plastic substrates, and to the use thereof.
• plastic substrates in particular from polyolefins, for example polypropylenes in pure form or in modified form (PP blend), are being used more and more extensively on account of the excellent overall properties in comparison to other plastics.
• polyolefins for example polypropylenes in pure form or in modified form (PP blend)
• PP blend modified form
• aqueous coating compositions based on epoxy resins or acrylate resins in the form of two-component systems are known from DE-A 41 23860 and EP-A 0 358979.
• plastic substrates especially untreated polyolefin substrates, however, adequate adhesion to the substrate cannot be achieved.
• imperfections such as stoves or pinholes, occur with thicker layers.
• DE-A-39 10 901 describes aqueous coating compositions for plastic parts which contain aqueous emulsions of acrylate resins or polyurethane resins, chlorinated polyolefins and optionally pigments or additives.
• the production of these coating compositions is very complex owing to a special melting process for the chlorinated polyolefins and the process step of an azeotropic distillation of organic solvent.
• aqueous adhesive primers based on chlorinated polyolefins, organic solvents, emulsifiers and pigments and, if appropriate, a film-forming binder can be used for plastic coating.
• solvent-based paints When solvent-based paints are applied to such primer layers, it can detach Primer and thus lead to defects in the paint.
• EP-A-0 587061 (H 32 088) describes an aqueous coating agent based on polyols, which also contains chlorinated polyolefins, organic solvents and, if appropriate, others
• binders and polyisocyanates It can be used as a primer, for single-layer painting or as a basecoat without prior priming for plastic substrates. Titanium dioxide, talc and carbon black can be used as pigments.
• the coating composition enables good adhesion, especially to
• Polyolefin plastic substrates as well as a smooth and trouble-free surface.
• Subsequent layers can also be applied in the usual way, e.g. by splashing, rolling, diving.
• the coating agent is not suitable for application of subsequent layers.
• the surface conductivity required for electrostatic subsequent coatings can be achieved by using electrically conductive primers or primers.
• the object of the present invention is to provide a coating agent for polyols in substrates, in particular polypropylene blends, which are aqueous and which, in addition to excellent adhesion, enable electrostatic application of subsequent layers to overcome the technical disadvantages mentioned.
• the use of chlorinated polyolefins is also to be reduced. This object is achieved by means of a coating agent based on crosslinking, water-dilutable 2-component (2K) resin systems which contain chlorinated and / or unchlorinated polyolefins and small amounts of organic solvent.
• Fillers 5 to 30% by weight of one or more organic solvents 25 to 75% by weight of water and
• polyisocyanates with an average of at least two free isocyanate groups per molecule, the sum of the above components is 100 wt .- and the ratio between the polyisocyanate component and the polyol component is selected so that the number of reactive NCO groups to the number of OH groups in a ratio of 5: 1 to 0.5: 1.
• customary paint additives further pigments and / or
• Fillers and optionally other binders may be included.
• the main solvent is water.
• the coating agent should be in the form of a two-component coating agent.
• One component contains the polyols and the other component contains the polyisocyanates.
• the polyol component is in water-diluted form before and the polyisocyanate component is dispersible together with the polyol component in water.
• the polyolefins, solvents, optionally further binders, pigments, fillers and further technical coatings additives can be contained in one of the two or in both components. It is important to ensure the storage stability of the individual components.
• the viscosity of the ready-to-apply coating agent can be adjusted to the desired range by diluting with water.
• the proportions of the conductive pigments and / or fillers are to be selected so that a sufficient subsequent coating can be carried out by electrostatic applications.
• the proportion of these pigments is in a range from 1 to 35% by weight.
• the conductive pigments can preferably be used in an amount of 2 to 30% by weight.
• the coating composition of the invention can be crosslinked at room temperature.
• catalysts can be added or the drying temperature can be increased. Preferred temperatures are 40 to 120 ° C.
• the polyol components which can be used according to the invention are known binders, for example polymers, based on free-radically polymerizable monomers which contain OH groups, polyesters containing 0H groups and / or polyurethanes containing OH groups.
• the number-average molecular weight is 300 to 2 ⁇ 10 6 , the hydroxyl number is 10 to 400.
• ester groups, urethane groups, ionic, nonionic groups or groups which can be converted into ionic groups can be present. These can be cationic or convertible substituents, for example amino groups.
• anionic substituents or those which can be converted into anionic groups are particularly suitable.
• the ionic group content is up to 400 milliequivalents / 100 g solid resin.
• the polyol component is in the form of an aqueous dispersion. Examples of polymers based on radical-polymerizable monomers are described in EP-A-0358979.
• These can be, for example, styrenes, (meth) acrylic acid alkyl esters, hydroxylalkyl esters of (meth) acrylic acid, monomers containing epoxide groups or amide groups, such as glycidyl (meth) acrylate or N-methoximethyl (meth) acrylamide.
• the ionic groups can be introduced via olefinically unsaturated monomers which have functionalities which can be converted into ionic groups, for example olefinically unsaturated mono- or dicarboxylic acids, such as e.g. Acrylic acid, maleic acid, itaconic acid and optionally half esters thereof or via compounds such as 2-acrylamido-2-methylpropanesulfonic acid.
• olefinically unsaturated mono- or dicarboxylic acids such as e.g. Acrylic acid, maleic acid, itaconic acid and optionally half esters thereof or via compounds such as 2-acrylamido-2-methylpropanesulfonic acid.
• the polymers are prepared by customary processes, e.g. by solution polymerization.
• Water-dispersible polyurethane resins are described, for example, in DE-A-41 24453 and DE-A-40 00 889.
• the polyurethane resins are e.g. prepared by reacting di- or polyvalent saturated linear or branched aliphatic or cycloaliphatic polyalcohols with linear or branched aliphatic cycloaliphatic or aromatic polyisocyanates and optionally linear or branched aliphatic or cycloaliphatic monoalcohols.
• Ionic groups are e.g. introduced by reacting portions of low molecular weight dialcohols which are anionic or
• Anion-capable group preferably a carboxyl group, contain.
• the polyurethane polyols preferably have an OH number of 20 to 250.
• the acid number is 50 to 150, preferably 10 to 60.
• the number average molecular weight is preferably 2,000 to 50,000.
• Polyester polyols with anionic groups which can be used according to the invention are, for example, the polyesters described in DE-A-32 13 160, DE-A-28 24 418 and US-A-3053 783. These can be linear or branched oil-free polyesters based on di- or polyvalent linear or branched aliphatic or cycloaliphatic saturated polyalcohols as well as linear or branched aliphatic, cycloaliphatic or aromatic dibasic or polybasic carboxylic acids, which can optionally be polycondensed with linear or branched aliphatic monoalcohols.
• Usable alcohols preferably contain 2 to 21 carbon atoms, e.g. Hexanediol, neopentylglycol, 2,2,4-trimethylpentanediol-1,3.
• the dibasic or polybasic carboxylic acids preferably contain 5 to 10 carbon atoms, for example isophthalic acid, terephthalic acid, 1,3-cyclohexanedicarboxylic acid or butylisophthalic acid.
• Anionic groups can also be incorporated by reaction with low molecular weight dialcohols which additionally contain acid groups capable of anion formation.
• the polyesters can also be increased in molecular weight by reaction with diisocyanates. Further modifications can optionally be made via reactive groups e.g. OH groups are carried out.
• the polyester polyols which can be used according to the invention can advantageously have a molecular weight of from 500 to 50,000, preferably from 2,000 to 50,000, particularly preferably from 1,000 to 15,000 and very particularly preferably from
• the OH number is 20 to 200, the acid number 10 to 150.
• the polyester polyols are prepared by known processes, for example azeotropically or in a melt by stepwise reaction. After reaching the desired end values, the polyester can be used
• Solvents are diluted.
• Polyesters are affected in their properties, for example increasing flexibility through higher-chain aliphatic alcohols,
• the polyols which can be used according to the invention can be converted into the water phase without further emulsifiers. If necessary, they may also contain small residues of organic solvent due to the manufacturing process. However, it is also possible to add emulsifiers, this addition should be as small as possible.
• the polyisocyanates which can be used according to the invention are customary lacquer and optionally hydrophilized and / or partially blocked polyisocyanates. They have an average of at least 2 free isocyanate groups per molecule. Such polyisocyanates are described, for example, in EP-A-0 358979. These are organic polyisocyanates, e.g. Diisocyanates with aliphatic, cycloaliphatic and / or aromatically bound free isocyanate groups. Under certain circumstances, different polyisocyanates can be mixed together. In addition, proportions of inert solvents can be added to achieve the viscosity. Examples of usable polyisocyanates are the known, conventional paint polyisocyanates such as hexamethylene diisocyanate, isophorone diisocyanate, tetramethylxylylene diisocyanate.
• oligomers can be converted into oligomers by known processes which have, for example, biuret, urethane, urethdione or isocyanurate groups.
• composition according to the invention can contain chlorinated and / or non-chlorinated polyolefins.
• chlorinated polyolefins Commercially available materials can be used individually or as a mixture as chlorinated polyolefins.
• This can be, in particular, chlorinated polyethylene, chlorinated polypropylene or chlorinated copolymers thereof with a degree of chlorination of preferably 10 to 45%.
• the number average molecular weight of the chlorinated polyolefins is preferably 700 to 70,000.
• the chlorinated polyolefins can be used in a modified manner, e.g. by incorporating polar groups such as maleic anhydride. They can be used as an organically dissolved resin powder or as an aqueous suspension or emulsion.
• non-chlorinated polyolefins for example in accordance with DE 43 08349 and JP 03 122 125 or polyolefin-acrylate copolymers, can be used DE 44 32 985 with an average molecular weight of 1000 to 50,000 can be used.
• these polymers can also be modified, e.g. by incorporating polar groups such as maleic anhydride and acrylic acid.
• the unchlorinated polyolefins can be used alone or in a mixture with the chlorinated polyolefins.
• the chlorinated and unchlorinated polyolefins can be used as an aqueous dispersion. Due to the production process, these may still have small proportions of organic solvents and proportions of ionic or non-ionic emulsifiers.
• the polyolefin content in the coating composition can be added in the form of a dispersion analogous to WO 93/01 244 or WO 90/12 056.
• organic solvents e.g. solvents customary in paint technology, such as ketones, hydrocarbons, alcohols, glycol ethers, such as Xylene, toluene, mesitylene, benzyl alcohol, are suitable.
• the amount of organic solvents should be kept as low as possible.
• the coating compositions according to the invention contain electrically conductive pigments and / or fillers.
• This can include pigments or fillers on an inorganic or organic basis.
• Commercially available opaque and transparent electrically conductive pigments and / or fillers such as are known, for example, for the antistatic finishing of polymeric coating materials for devices, surfaces and components, can be used.
• These can be conductive coated Ti0 2 , barium sulfate, doped tin dioxide, doped zinc oxide (doped eg with aluminum, gallium, antimony and bismuth), conductive coated potassium titanate and conductive types of carbon black.
• these can give black to white colorations, for example when using carbon black or titanium dioxide types.
• black to white colorations for example when using carbon black or titanium dioxide types.
• colored pigments By adding colored pigments, further colorations can be achieved if necessary. Light colors are preferred.
• the pigments are preferably rubbed directly into the polyol component. If necessary, it is possible, especially for pigments that are difficult to disperse, e.g. Carbon black types to use a pigment paste using additional binders (grind resins) e.g. based on polyurethane, polyacrylate, polyether and polyester resin. The pigments are finely dispersed therein. The aggregates and procedures required for this are familiar to the person skilled in the art.
• Conductive pigments can be present in the composition according to the invention in a content of 1 to 35% by weight. 1 to 5% by weight are preferably used for dark to black pigments and 5 to 25% by weight for gray to light pigments.
• the coating agents may optionally contain further pigments and additives.
• the usual paint additives such as wetting agents, dispersing agents, anti-foaming agents, flow promoters, catalysts, rheology additives and anti-cratering agents, can be used as additives.
• the coating compositions of the invention may also contain proportions of further binders which preferably do not react with the crosslinking components. This can e.g. watery
• the film-forming resins are present in the water phase. It can be neutralized in whole or in part in order to obtain a stable aqueous emulsion.
• the binder component preferably contains the polyolefin preparation and, if appropriate, the further non-reactive, water-dilutable binders. This component may also contain additives and / or pigments or fillers.
• the second component contains the polyisocyanates. Under certain circumstances, further additives (eg anti-foaming agents) may be contained in this component. Portions of the polyolefin preparation can also be incorporated.
• the polyisocyanate component is dispersed in the aqueous dispersion of the binder component.
• the coating agent according to the invention can be adjusted to a suitable processing viscosity with water.
• Plastic substrates in particular modified or unmodified polyolefins, are preferably suitable as substrates.
• examples of these are in particular polyethylene or polypropylene substrates and substrates made from copolymers or mixtures thereof, e.g. PP-EPDM blends.
• the coating agent according to the invention is applied to the preferably non-pretreated substrate, if necessary after cleaning it.
• the coating is then chemically crosslinked, if necessary this can be supported by an increased temperature.
• the crosslinking temperature of the coating agent can be selected depending on the temperature sensitivity of the substrate, since the coating agents according to the invention can crosslink over a wide temperature range. A temperature range from 40 to 120 ° C. is preferred.
• the coating compositions according to the invention are used in particular as electrically conductive adhesive primers. Further coatings, for example basecoat, clearcoat or solid-color coatings, can then be applied to the resulting conductive plastic coating using electrostatic application methods. These enable a significant reduction in overspray compared to conventional application methods.
• the multilayer structures obtained show very good adhesion to the substrate, good cold elasticity and no surface change when exposed to moisture.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Polymers & Plastics (AREA)
• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Manufacturing & Machinery (AREA)
• Life Sciences & Earth Sciences (AREA)
• Materials Engineering (AREA)
• Wood Science & Technology (AREA)
• Paints Or Removers (AREA)
• Application Of Or Painting With Fluid Materials (AREA)

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• 1996
  • 1996-10-26 DE DE19644615A patent/DE19644615C1/de not_active Expired - Fee Related
• 1997
  • 1997-10-21 EP EP97951131A patent/EP0870000A1/de not_active Withdrawn
  • 1997-10-21 JP JP10520002A patent/JP2000505141A/ja not_active Abandoned
  • 1997-10-21 CA CA002240674A patent/CA2240674A1/en not_active Abandoned
  • 1997-10-21 TR TR1998/01230T patent/TR199801230T1/xx unknown
  • 1997-10-21 WO PCT/EP1997/005791 patent/WO1998018875A1/de not_active Application Discontinuation

Non-Patent Citations (1)

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