Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F265/00—Macromolecular compounds obtained by polymerising monomers on to polymers of unsaturated monocarboxylic acids or derivatives thereof as defined in group C08F20/00
  • C08F265/02—Macromolecular compounds obtained by polymerising monomers on to polymers of unsaturated monocarboxylic acids or derivatives thereof as defined in group C08F20/00 on to polymers of acids, salts or anhydrides
• • 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
  • C09D151/00—Coating compositions based on graft polymers in which the grafted component is obtained by reactions only involving carbon-to-carbon unsaturated bonds; Coating compositions based on derivatives of such polymers

Definitions

• the invention relates to a method for producing a multilayer protective and / or decorative coating on a substrate surface, in which
• a suitable pigmented basecoat composition is applied to the substrate surface.
• the invention also relates to aqueous coating compositions, water-thinnable polyacrylate resins and a process for producing water-thinnable polyacrylate resins. resin.
• the method according to the preamble of claim 1 is known. It is used in particular for the production of automotive metal effect coatings (see, for example, US-A-3,639,147, DE-A-33 33 072 and EP-A-38127).
• aqueous top coating compositions for economic and ecological reasons, it is desirable to use aqueous top coating compositions in stage (3) of the so-called “base coat-clear coat” process described above.
• top coating compositions must be sprayable using automatic painting equipment. For this purpose, they have to have such a high solids content at spray viscosity that lacquer films with a sufficient layer thickness are obtained with one to two spray coats (cross coats), and they have to deliver baked lacquer films which have a good appearance (good flow, high gloss, good) Topcoat level ...) show.
• the aqueous top coating composition disclosed in Example 2 of EP-A-38127 does not meet all of the above requirements.
• the task on which the present invention is based consists in the provision of aqueous top coating compositions which meet the above-mentioned requirements.
• top coating compositions which contain a water-dilutable polyacrylate resin as a binder, which is obtainable by (I)
• (b2) an ethylenically unsaturated monomer copolymerizable with (b1), (b3), (al) and (a2), which carries at least one hydroxyl group per molecule and is essentially free of carboxyl groups or a mixture of such monomers and if necessary
• (b3) a copolymerizable with (b1), (b2), (a1) and (a2), essentially carboxyl-free ethylenically unsaturated monomers or a mixture of such monomers
• Polyacrylate resin is at least partially neutralized and dispersed in water, the sum of the weight fractions of (al) and (a2) always giving 100% by weight and (bl), (b2), (b3), (al) and (a2) be selected in type and amount so that the polyacrylate resin has a hydroxyl number of 40 to 200, preferably 60 to 140, an acid number of 20 to 100, preferably 25 to 50 and a glass transition temperature (T_) of -40 ° C to + 60 ° C, preferably -20 ° C to + 40 ° C, has.
• T_ glass transition temperature
• the pigmented base coating compositions to be applied in stage (1) of the process according to the invention are well known (cf. e.g. US-A-3,639,147, EP-A-38127, DE-A-33 33 072 and EP-A-279 813).
• base coating compositions containing metal pigments, in particular aluminum pigments are preferably used. In this way, metallic effect coatings are obtained.
• component (a1) can be any ethylenically unsaturated monomer which carries at least one carboxyl group per molecule and can be copolymerized with (b1), (b2) and (b3) or a mixture of such monomers.
• Acrylic acid and / or methacrylic acid are preferably used as component (a1).
• other ethylenically unsaturated acids with up to 6 carbon atoms in the molecule can also be used. Examples of such acids are ethacrylic acid, crotonic acid, maleic acid, fumaric acid and itaconic acid.
• component (al) e.g. succinic acid mono (meth) acryloyloxyethyl ester and phthalic acid mono (meth) acryloyloxyethyl ester can also be used.
• Component (a2) can be any ethylenically unsaturated monomer copolymerizable with (bl), (b2), (b3) and (al) or a mixture of such monomers. All monomers listed in the description of components (b1), (b2) and (b3) can be used as component (a2).
• component (al) it is preferred to use 100% by weight of component (al). In other words: it is preferred to use component (a1) without admixing component (a2).
• Component (bl) can be any of those which are copolymerizable with (b2), (b3), (al) and (a2) and are essentially free of carboxyl groups
• Esters of (meth) acrylic acid or a mixture of such (meth) acrylic acid esters can be used.
• Examples include alkyl acrylates and alkyl methacrylates with up to 20 carbon atoms in the alkyl radical, such as methyl, ethyl, propyl, butyl, hexyl, ethylhexyl, stearyl and lauryl acrylate and methacrylate .
• alkyl acrylates and / or alkyl methacrylates are preferably used as (b1) components which consist of at least 25% by weight of n-butyl or t-butyl acrylate and / or n-butyl or t-butyl methacrylate.
• component (b2) all ethylenically unsaturated monomers which can be copolymerized with (bl), (b3), (al) and (a2) and which carry at least one hydroxyl group per molecule and are essentially free from carboxyl groups, or a mixture of such monomers can be used .
• Hydroxyalkyl esters of acrylic acid, methacrylic acid or another “ ⁇ , ß-ethylenically unsaturated carboxylic acid are mentioned as examples. These esters can be derived from an alkylene glycol which is esterified with the acid, or they can be obtained by reacting the acid with an alkylene oxide.
• hydroxylalkyl esters of acrylic acid and methacrylic acid in which the hydroxyalkyl group contains up to 4 carbon atoms, reaction products of cyclic esters, such as, for example, £ -caprolactone and these hydroxyalkyl esters or mixtures of these hydroxyalkyl esters or Caprolactone-modified hydroxyalkyl esters are used.
• hydroxyalkyl esters examples include 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 3-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 3-hydroxypropyl methacrylate, 2-hydroxyethyl methacrylate, 4-hydroxybutyl acrylate and 4-hydroxybutyl methacrylate.
• esters of other unsaturated acids such as ethacrylic acid, crotonic acid and similar acids with up to about 6 carbon atoms per molecule can also be used.
• Component (b3) which can be used is all copolymerizable with (b1), (b2), (a1) and (a2), essentially carboxyl-free ethylenically unsaturated monomers or mixtures of such monomers.
• Vinylaromatic hydrocarbons such as styrene, (-alkylstyrene and vinyltoluene) are preferably used as component (b3).
• the polyacrylate resins used according to the invention can be prepared by adding 60 to 100% by weight of component (a1) together with 0-40% by weight of component (a2) to an organic solvent or solvent mixture, at least there in the presence of a polymerization initiator and after the addition of components (a1) and (a2) has ended, a mixture (b) consisting of components (b1), (b2) and optionally (b3) to the organic solvent or solvent mixture is given and is polymerized there in the presence of at least one polymerization initiator. After the end of the polymerization, the polyacrylate resin obtained is at least partially neutralized and dispersed in water. The sum of the parts by weight of (al) and (a2) is always
• the components (a1), (a2), (b1), (b2) and (b3) are selected in their type and amount so that the polyacrylate resin has a hydroxyl number of 40 to 200, preferably 60 to 140, an acid number of 20 to 100, preferably 25 to 50 and a glass transition temperature (T Q ) of -40 ° C to +60 ⁇ C, preferably -20 ° C to + 40 ° C.
• Component (a1) - optionally together with component (a2) - is preferably added within 10 to 60 minutes, particularly preferably within 15 to 45 minutes added to the organic solvent or solvent mixture and polymerized there in the presence of at least one free radical-forming initiator.
• Mixture (b) is preferably added to the organic solvent or solvent mixture within 2 to 8 hours, particularly preferably within 3 to 6 hours, and is polymerized there in the presence of at least one free radical initiator.
• the polyacrylate resins to be used according to the invention can also be prepared by adding component (al) (optionally together with a2) and mixture (b) alternately to an organic solvent or solvent mixture and there in the presence of at least one free radical initiator are polymerized.
• the partial amounts should each consist of at least 10% by weight of the total amount of component (a1) and (a2) or mixture (b) to be used.
• the polyacrylate resin obtained is at least partially neutralized and dispersed in water. The sum of the parts by weight of (a1) and (a2) is always 100% by weight.
• the components (a1), (a2), (b1), (b2) and (b3) are selected in their type and amount so that the polyacrylate resin has a hydroxyl number of 40 to 200, preferably 60 to 140, an acid number of 20 to 100, preferably 25 to 50 and a glass transition temperature (T G ) of -40 ° C to + 60 ° C, preferably -20 ⁇ C to + 40 ° C.
• a first step one of 30 to 70% by weight, preferably one of 40 to 60% by weight, particularly preferably one of 50% by weight of the total amount of component ( b) existing subset of component (b) (subset 1) to the organic solvent or Given solvent mixture and polymerized in the presence of at least one free radical initiator.
• a second step one of 30 to 70% by weight, preferably one of 40 to 60% by weight, particularly preferably one of 50% by weight of the total amount of component to be used (al) existing portion of component (al) (portion 2) added to the organic solvent or solvent mixture and polymerized in the presence of at least one free radical initiator.
• portion 2 in a third step one of 30 to 70% by weight, preferably one of 40 to 60% by weight, particularly preferably one of 50% by weight of the total amount of component (b ) existing subset of component (b)
• portion 4 consisting of 50% by weight of the total amount of component (a1) to be added to the organic solvent or solvent mixture and mixed in at least one free radical initiator is polymerized.
• the polyacrylate resin obtained is at least partially neutralized and dispersed in water.
• the sum of the parts by weight of (a1) and (a2) is always 100% by weight.
• the components (a1), (a2), (b1), (b2) and (b3) are selected in their type and amount so that the polyacrylate resin has a hydroxyl number of 40 to 200, preferably 60 to 140, an acid number of 20 to 100, preferably 25 to 50 and a glass transition temperature (T Q ) of -40 ° C to + 60 ° C, preferably -20 ⁇ C to + 40 ° C.
• the aliquots 1 and 3 are preferably added within 1 to 4 hours, particularly preferably within 1 1/2 to 3 hours.
• the aliquots 2 and 4 are preferably added within 5 to 30 minutes, particularly preferably within 7 to 20 minutes.
• the organic solvents and polymerization initiators used are the solvents and polymerization initiators customary for the production of polyacrylate resins and suitable for the production of aqueous dispersions.
• useful solvents are butyl glycol, 2-methoxypropanol, n-butanol, methoxybutanol, n-propanol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether Called -3-methoxybutanol.
• Free radical-forming initiators such as e.g. Benzoyl peroxide, azobisisobutyronitrile and t-butyl perbenzoate called.
• the polymerization is carried out at a temperature of 80 to 160 ° C, preferably 120 to 160 ° C. The polymerization is complete when essentially all of the monomers used have been reacted.
• the components (a1), (a2), (b1), (b2) and (b3) are selected in their type and amount such that the reaction product has a hydroxyl number of 40 to 200, preferably 60 to 140, an acid number of 20 to 100 , preferably 25 to 50 and a glass transition temperature (T-,) of -40 ° C to + 60 ° C, preferably shows -20 ° C to + 40 ° C.
• the glass transition temperatures of polyacrylate resins can be calculated approximately using the following formula:
• the amount and rate of addition of the initiator is preferably controlled so that the polyacrylate resin obtained has a number average molecular weight of 2500 to 20,000. It is particularly preferred to start the initiator addition at the same time as the addition of the polymerizable components (al), (a2) and (b) and about half an hour after the addition of the polymerizable components (al), (a2) and (b) has been terminated.
• the reaction mixture is then kept at the polymerization temperature (generally about 1 1/2 hours) until all of the monomers used have essentially been completely reacted.
• “Substantially completely converted” is intended to mean that preferably 100% by weight of the monomers used have been reacted, but that it is also possible for a low residual monomer content of at most up to 0.5% by weight.
• the polyacrylate resins according to the invention are produced by adding 40 to 87.5% by weight, preferably 55 to 80% by weight of component (b1), 10 to 45% by weight, preferably 12 to
• component (b2) 35% by weight of component (b2), 0 to 25% by weight, preferably 8 to 18% by weight of component (b3), 2.5 to 15% by weight, preferably 3 to 7% by weight .-% of component (al) and 0 to 6 wt .-% of component (a2) are used, the sum of the parts by weight of (bl), (b2), (b3), (al) and (a2) always 100 wt .-% results.
• the polyacrylate resin obtained is at least partially neutralized and dispersed in water.
• Both organic bases and inorganic bases such as ammonia and hydrazine can be used for the neutralization.
• Primary, secondary and tertiary amines e.g. Ethylamine, propylamine, diethylamine, dibutylamine, cyclohexylamine, benzylamine, morpholine, piperidine and triethanolamine are used.
• Tertiary amines are particularly preferably used as neutralizing agents, in particular dimethylethanolamine, triethylamine, tripropylamine and tributylamine.
• the neutralization reaction is generally carried out by mixing the neutralizing base with the polyacrylate resin.
• the amount of base used is preferably such that the top coating composition has a pH of 7-8.5, preferably 7.2 to 7.8.
• the partially or completely neutralized polyacrylate resin is then dispersed by adding water. This creates an aqueous polyacrylate resin dispersion. If necessary, some or all of the organic solvent be distilled off medium.
• the polyacrylate resin dispersions according to the invention contain polyacrylate resin particles, the average particle size of which is preferably between 60 and 250 nm (measurement method: laser light scattering, measuring device: Malvern Autosizer 2C).
• aqueous polyacrylate resin dispersions obtained in this way are prepared by admixing an aminoplast resin and, if appropriate, other additives, such as e.g. Leveling aids, UV stabilizers, transparent pigments, etc. are given top coating compositions according to the invention.
• top coating compositions according to the invention preferably contain so much aminoplast resin that the weight ratio between polyacrylate resin solid and aminoplast resin solid is 60:40 to 90:10, particularly preferably 70:30 to 85:15.
• all aminoplast resins that can be processed into a stable top coating composition with the polyacrylate resin according to the invention can be used as crosslinking agents.
• Melamine-formaldehyde resins which are partially or completely etherified with aliphatic alcohols, which preferably contain 1 to 4 carbon atoms per molecule, are preferably used as crosslinking agents.
• top coating compositions according to the invention are preferred for spray viscosity (generally 20 to 40 sec. Run-out time from DIN cup 4 (DIN 53211 (1974))) and a pH of 7.0 to 8.5 ⁇ set to 7.2 to 7.8.
• the top coating compositions of the invention are preferred for spray viscosity (generally 20 to 40 sec. Run-out time from DIN cup 4 (DIN 53211 (1974))) and a pH of 7.0 to 8.5 ⁇ set to 7.2 to 7.8.
• organic cosolvents have a relatively low proportion of organic cosolvents (less than 35% by weight, based on the total solids content of binders and crosslinking agents).
• top coating compositions according to the invention are used together with water-thinnable base coating compositions for the production of metallic effect coatings, then metallic effect coatings are obtained in which the transparent top layer adheres particularly well to the base layer.
• the top coating compositions according to the invention can also contain crosslinked polymer microparticles, such as are disclosed, for example, in EP-A-38127 and / or other compatible resins such as water-dilutable or water-soluble polyacrylate resins, polyester resins, alkyd resins or epoxy resin esters included, and they can also be pigmented.
• crosslinked polymer microparticles such as are disclosed, for example, in EP-A-38127 and / or other compatible resins such as water-dilutable or water-soluble polyacrylate resins, polyester resins, alkyd resins or epoxy resin esters included, and they can also be pigmented.
• Pl> 20 parts by weight of butyl glycol are placed in a 4 1 steel kettle equipped with two monomer feeds, an initiator feed, stirrer, thermometer, oil heater and reflux condenser and heated to 140 ° C. Then a solution of 4.5 parts by weight of butyl perbenzoate in 5 parts by weight of butyl glycol were added at such a rate that the addition of 4 h, 30 min was completed. With the beginning of the addition of the butyl perbenzoate solution, the addition of component (a1) is also started (cf. Table 1). Component (a1) is added at a rate such that the addition is complete after 20 minutes.
• P2 20 parts by weight of butylglycol are placed in a 4 1 steel kettle equipped with two monomer feeds, an initiator feed, stirrer, thermometer, oil heating and reflux condenser and heated to 140.degree.
• a solution of 4.5 parts by weight of butyl perbenzoate in 5 parts by weight of butyl glycol is then added at such a rate that the addition is complete after 4 hours and 30 minutes.
• the resin solution thus obtained is neutralized with dimethylethanolamine at 95 ° C. to a degree of neutralization of 80%. Sufficient water is then added so that the solids content of the dispersion is about 60% by weight.
• P3J inlets equipped with two monomer into a 4 1 steel vessel, an initiator inlet, stirrer, thermometer, oil heating and reflux condenser are placed 20 parts by weight Butyl ⁇ glycol and heated to 140 C ⁇ . Then a solution of 4.5 parts by weight of butyl perbenzoate in 5 parts by weight of butyl glycol is added at such a rate that the addition after 4 h, 30 min. is completed. At the beginning of the addition of the butyl perbenzoate solution, the addition of 33.3% by weight of the total amount of component (al) (partial amount 1) to be used is also started. The portion 1 is added at such a rate that the addition is complete after 10 minutes.
• Partial amount 1 becomes 50% by weight of the total amount of the mixture of (bl), (b2) and (b3) (partial amount 2) to be used within 1 hour, 55 minutes. admitted.
• 33.3% by weight of the total amount of component (al) (partial amount 3) to be used are added within 10 minutes.
• portion 3 the remaining 50% by weight of the total amount of the mixture of (bl), (b2) and (b3) (portion 4) to be used are added within 1 h, 55 min.
• portion 4 the remaining 33.33% by weight of the total amount of component (al) (portion 5) to be used is finally added within 10 minutes.
• the reaction mixture is then kept at 140 ° C. until the solids content of the resin solution is at least 80% by weight (1 h, 130 ° C.).
• the resin solution thus obtained is neutralized with dimethylethanolamine at 95 ° C. to a degree of neutralization of 80%. Sufficient water is then added so that the solids content of the dispersion is about 60% by weight.
• topcoat compositions are prepared and sprayed with a 10% aqueous dimethylethanolamine solution and distilled water (24 s run-out time from DIN cup 4 (DIN 53211 (1974))) and a pH of 7.4 to 7.5.
• the top coat Processing compositions contain 20% by weight of organic cosolvents, based on the total solids content of polyacrylate resin and melamine-formaldehyde resin.
• the applied base coating composition is 10 min. at room temperature and 10 min. getrock ⁇ net at 80 ° C.
• a top coating composition obtained in accordance with point B is then sprayed onto the base layer in two cloisters with an intermediate flash-off time of one minute.
• the multilayer coatings obtained in this way were subjected to several tests. The test results are summarized in the following table:
• the monomers (al), (bl), (b2) and (b3) used to prepare the polyacrylate resins P1 and P3 according to the invention are mixed and polymerized.
• the polymerization conditions are the same as in the production of the polyacrylate resins P1 and P3 according to the invention.
• component (a1) does not precede the mixture of (bl), (b2) and (b3) as in Pl and does not alternate as in P3, but instead is added together with (bl), (b2) and (b3).
• An aqueous top coating composition prepared from the polyacrylate resin V according to B prepared in this way has a viscosity of 24 DIN seconds (run-out time from DIN cup 4 (DIN 53211 (1974))) and a pH of 7.4 to 7 , 5 only has a solids content of 24.1% by weight.
• the following diagram shows the viscosities of the polyacrylate dispersions P1 and P3 prepared according to A and diluted with water as a function of the solids content of the dispersions in comparison to an analogous dispersion of the polyacrylate resin V (pH value of the dispersions: 7.8). It is clear that the viscosities of the polyacrylate resin dispersions P1 and P3 at solids contents of 25 to about 53% by weight are lower than the viscosity of the dispersion of the polyacrylate resin V.
• FK solids content in 6% by weight

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• 1988
  • 1988-10-12 DE DE3834738A patent/DE3834738A1/de not_active Withdrawn
• 1989
  • 1989-09-26 EP EP89911034A patent/EP0441800A1/de active Pending
  • 1989-09-26 EP EP19890117746 patent/EP0363723B1/de not_active Expired - Lifetime
  • 1989-09-26 US US07/674,370 patent/US5266361A/en not_active Expired - Lifetime
  • 1989-09-26 AT AT89117746T patent/ATE77976T1/de active
  • 1989-09-26 JP JP1510298A patent/JPH072929B2/ja not_active Expired - Lifetime
  • 1989-09-26 WO PCT/EP1989/001126 patent/WO1990003851A1/de not_active Application Discontinuation
  • 1989-09-26 ES ES198989117746T patent/ES2033505T3/es not_active Expired - Lifetime
  • 1989-09-26 AU AU43353/89A patent/AU625803B2/en not_active Ceased
  • 1989-09-26 BR BR898907720A patent/BR8907720A/pt not_active IP Right Cessation
  • 1989-09-26 DE DE8989117746T patent/DE58901811D1/de not_active Expired - Lifetime
  • 1989-09-28 CA CA000614194A patent/CA1340621C/en not_active Expired - Fee Related
  • 1989-10-05 ZA ZA897581A patent/ZA897581B/xx unknown

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