Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D3/00—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials
  • B05D3/02—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials by baking
  • B05D3/0254—After-treatment
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D7/00—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials
  • B05D7/14—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials to metal, e.g. car bodies
  • B05D7/142—Auto-deposited coatings, i.e. autophoretic coatings
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D7/00—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials
  • B05D7/50—Multilayers
  • B05D7/52—Two layers
  • B05D7/54—No clear coat specified
  • B05D7/542—No clear coat specified the two layers being cured or baked together
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D1/00—Processes for applying liquids or other fluent materials
  • B05D1/36—Successively applying liquids or other fluent materials, e.g. without intermediate treatment
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D2202/00—Metallic substrate
  • B05D2202/10—Metallic substrate based on Fe
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D7/00—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials
  • B05D7/50—Multilayers
  • B05D7/52—Two layers
  • B05D7/54—No clear coat specified
  • B05D7/544—No clear coat specified the first layer is let to dry at least partially before applying the second layer

Definitions

• This invention relates to a coated article comprising a metal surface, a first layer of an uncured autodeposition coating and a second uncured paint layer deposited sequentially on the surface without intermediate curing of the autodeposition coating, a process of co-curing said autodeposition coating and paint layer or layers, and a cured coated article having chemical bonds between the cured autodeposition coating layer and at least the cured paint layer immediately adjacent to the cured autodeposition coating layer.
• the coated article and process are useful in manufacture of corrosion resistant painted articles having metal surfaces.
• One benefit of the invention is a reduction in the number of steps, floor space, time and energy required to produce the corrosion resistant painted articles and, in some embodiments, a chemical bonding between the autodeposition and paint layers that improves adhesion.
• Autodeposition coatings which are adherent coatings formed on metal surfaces, comprise an organic polymer coating deposited by electroless chemical reaction of the coating bath with the metal surfaces. Autodeposition has been in commercial use on ferrous surfaces, in particular steel surfaces, for about thirty years and is now well established for that use. For details, see for example, U.S. Pat. No. 3,592,699 (Steinbrecher et al.); U.S. Pat. Nos. 4,108,817 and 4,178,400 (both to Lochel); U.S. Pat. No. 4,180,603 (Howell. Jr.); U.S. Pat. Nos. 4,242,379 and 4,243,704 (both to Hall et al.); U.S. Pat. No.
• Autodeposition compositions are usually in the form of liquid, usually aqueous, solutions, emulsions or dispersions in which active metal surfaces of inserted objects are coated with an adherent resin or polymer film that increases in thickness the longer the metal object remains in the bath, even though the liquid is stable for a long time against spontaneous precipitation or flocculation of any resin or polymer, in the absence of contact with active metal.
• the resin or polymer used in autodeposition baths is desirably insoluble in water.
• Active metal is defined as metal that is more active than hydrogen in the electromotive series, i.e., that ttorney oc e o.
• the working autodeposition baths are acidic in nature, having pHs ranging from about 1 to about 4.
• Such compositions, and processes of forming a coating on a metal surface using such compositions are commonly denoted in the art, and in this specification, as “autodeposition” or “autodepositing” compositions, dispersions, emulsions, suspensions, baths, solutions, processes, methods, or a like term.
• the autodeposited coating undergoes a rinse step and a cure step prior to the addition of any paint layer. That is, the autodeposition coating is dried and fully cross-linked before addition of another paint.
• two ovens are required; the first oven is used for curing (cross-linking) the autodeposition coating.
• powder or liquid paint for example a topcoat
• the part enters a second oven for cure of this second layer, e.g. topcoat, of paint.
• the cure step for the autodeposition coating conventionally takes place at temperatures of 165-204°C for a duration of 10 to 30 minutes. These temperatures have been thought to be required to achieve adequate cross-linking of the autodeposition coating, and use of this cure step to likewise cure secondary paint layers was not considered possible due to gases exiting the autodeposition coating during curing. Prior art attempts to do so resulted in paint defects in the second paint layer surface. As such, after cure of an autodeposition coating in a conventional process, the coated part would be subjected to a second painting step and a second cure step for the paint.
• electrodeposited coating is formulated with low molecular weight epoxy and higher loading of blocked isocyanate and other byproducts (amine and solvent) which requires the electrodeposited coating to be fully cured prior to topcoat application as exiting byproducts cause surface defects.
• Advantages of co-curing include eliminating processing steps, reducing oven length and reducing oven temperature. It is also desirable to have an uncross-linked autodeposition coating that is dry to handle which allows for transient time, such as for example where a topcoat is to be applied at a location different from the autodeposition coating.
• It is an object of the invention to meet the above-described needs and avoid at least some of the drawbacks of the prior art by providing a process for co-curing an autodeposition coating and paint layer comprising: a) contacting a substrate having at least one metal surface with an autodeposition bath at a pH of between about 1 and about 4, for a sufficient time and at a sufficient temperature to deposit an uncured autodeposition coating thereon; b) rinsing with water; c) optionally, contacting the uncured autodeposition coating with an alkaline or acidic rinse; d) optionally, dewatering the uncured autodeposition coating; e) depositing an uncured paint layer on the uncured autodeposition coating; and f) co-curing the uncured autodeposition coating and uncured paint layer.
• the second layer is a liquid paint layer, which may be subsequently dried prior to curing.
• the second layer is a powder paint layer.
• the first layer may be dewatered prior to deposition of the powder paint layer.
• one shared cross-linked polymer chain comprising a first polymer chain portion in said first layer and a second polymer chain portion in said second layer.
• the autodeposition working bath comprises: a. at least 1.0%, based on the whole composition, of a component of dissolved, dispersed, or both dissolved and dispersed film forming polymer molecules; b.
• At least one emulsifier in sufficient quantity to emulsify any water insoluble part of any other component so that, in the autodepositing liquid composition, no separation or segregation of bulk phases that is perceptible with normal unaided human vision occurs during storage at 25°C for at least 24 hours after preparation of the autodepositing liquid composition, in the absence of contact of the autodepositing liquid composition with any metal that reacts with the autodepositing liquid composition to produce therein dissolved metal cations with a charge of at least two; c. at least one cross-linker, d.
• At least one dissolved accelerator component selected from the group consisting of acids, oxidizing agents, and complexing agents that are not part of immediately previously recited components, this accelerator component being sufficient in strength and amount to impart to the total autodepositing liquid composition an oxidation-reduction potential that is at least 100 mV more oxidizing than a standard hydrogen electrode; e. optionally, at least one filler; f. optionally, at least one colorant, g. optionally, at least one coalescing agent, and h. water.
• the film forming polymer molecules are selected from polymers and copolymers of acrylic, polyvinyl chloride, epoxy, polyurethane, phenol- formaldehyde condensation polymers, epoxy-acrylic hybrid polymer and mixtures thereof; ttorney oc e o.
• At least one dissolved accelerator component selected from the group consisting of acids, oxidizing agents, and complexing agents that are not part of immediately previously recited components (1), (2) or (3), this accelerator component being sufficient in strength and amount to impart to the total autodepositing liquid composition an oxidation-reduction potential that is at least 100 mV more oxidizing than a standard hydrogen electrode; the pH of the autodeposition bath being between about 1 and about 4, for a sufficient time and at a sufficient temperature to deposit an uncured autodeposition coating on said at least one active metal surface; b) rinsing with water; c) optionally, contacting the uncured autodeposition coating with an alkaline or acidic rinse; d) optionally, dewatering the uncured autodeposition coating; e) depositing an uncured paint layer on the uncured autodeposition coating; and f) co-curing the uncured autodeposition coating and uncured paint layer.
• the pH of the autodeposition bath being between about 1 and about 4, for a sufficient time and at a sufficient temperature
• the uncured autodeposition coating comprises a cross-linker and wherein said coating is dewatered at a temperature of about 10 to 50, preferably 13 to 43 degrees less than the cross- linker de-blocking temperature.
• a process according to the invention for co-curing an autodeposition coating and paint layer comprising: a) contacting a substrate having at least one metal surface with an autodeposition bath at a pH of between about 1 and about 4, for a sufficient time and at a sufficient temperature, a typical autodeposition bath is maintained at ambient temperature, for example about Attorney oc et No. H50 I 99
• the first layer and the second layer of the present invention can be applied in any conventional manner that does not unduly interfere with the objects of the invention.
• a metal surface is degreased and rinsed with water before applying the autodeposition coating.
• Conventional techniques for cleaning and degreasing the metal surface to be treated according to the invention can be used for the present invention.
• Step (b) rinsing with water can be performed by exposure to running water, but will ordinarily be performed by immersion for from 10 to 120 seconds, or preferably from 20 to 60 seconds, in water at ordinary ambient temperature.
• the metal surface to be coated is cleaned with an acidic cleaner prior to autodeposition coating.
• the acidic cleaner may contain inorganic and /or organic acid. Suitable acidic cleaners such as 182 A Cleaner, 7005 Cleaner, 7150 Cleaner, 7310 Cleaner, 7320 Cleaner are commercially available from Henkel Corporation.
• an ultrasonic water rinse as is known in the art, can be used after the cleaning step.
• Any method can be used for contacting a metal surface with the autodeposition composition of the present invention. Examples include immersion (e.g., dipping), spraying or roll coating, and the like. Immersion is usually preferred.
• the metal surface is left in contact with the autodeposition bath for a sufficient time, for example from 30-300 seconds, to deposit a first layer of an uncured autodeposition coating on the metal surface.
• the substrate is then removed from the autodeposition bath and rinsed with water.
• an acidic or alkaline rinse can be used after or instead of the water rinse and may be maintained at temperatures of 10°C up to about 90°C.
• An optional dewatering step may also be used and is differentiated from the cure step by the lower temperatures and/or shorter time of heating used such that less than 50, 40, 30, 20, 10, 5 or 1 percent by dry weight of resin or polymer in the uncured autodeposition coating chemically reacts with itself or with other molecules to form cross-linkages.
• dewatered uncured autodeposition coating remains substantially uncross-linked after dewatering until subjected to a curing step.
• substantially uncross-linked as used herein means, with increasing preference in the order given, less than 50, 40, 30, 20, 10, 5 or 1 percent by dry weight of resin in the autodeposition coatings is cross-linked.
• a second layer of uncured paint may be applied to a wet uncured autodeposition coating or the uncured autodeposition layer may be dewatered prior to application of the second layer of uncured paint.
• the first layer of uncured autodeposition coating is dewatered prior to depositing an uncured paint layer on the uncured autodeposition coating.
• the dewatering step may take place after application of the second layer of uncured paint to the first layer of uncured autodeposition coating.
• Temperatures for the dewatering step vary depending upon the temperature at which the uncured autodeposition coating cross-links.
• the peak metal temperature during dewatering is desirably less than a temperature at which a cross-linker present in the autodeposition coating is activated, that is begins to react to form cross-linkages. If both layers are applied prior to dewatering, the temperature for dewatering is selected such that it is less than the temperature at which the cross-linker in the autodeposition coating is activated or the curing temperature of the second paint layer, e.g. topcoat, whichever is lower.
• the first layer of uncured autodeposition coating is dewatered at temperatures ranging from 90°C to 160°C for 1- 10 minutes, preferably at least 100°C. In a second embodiment, higher dewatering temperatures of 90°C up to 165°C have been found to be acceptable provided that the duration of heating and part geometry are selected such that the uncured autodeposition coating remains substantially uncross-linked.
• the second layer of uncured paint can be applied by conventional industrial painting methods known to those of skill in the manufacturing arts, such as spraying, dipping, electrostatic deposition, powder coating techniques and the like, provided that such methods do not unduly interfere with the corrosion resistance of the cured article by for example dissolving the uncured autodeposition coating.
• a single curing step is provided for curing the first and second layers on the metal surface.
• temperatures used to co-cure the two layers are greater than or equal to a temperature at which a cross-linker present in the autodeposition coating is activated and are of a duration sufficient to chemically cross-link at least 50, 60, 70, 80, 90 or 100 percent of the ttorney oc e o.
• the peak metal temperature of the cure step ranges from about 175 0 C to about 235°C.
• the first and second layers are co-cured, meaning that the autodeposition coating undergoes a first cross-linking reaction and the second layer of paint is cured and/or undergoes a second cross-linking reaction.
• the first and second cross-linking reactions may be of different types or may be of the same type, such as by way of non-limiting example reactions of OH groups with NCO groups.
• the autodeposition coating layer and paint layer cross-link to each other providing improved paint adhesion.
• the autodeposition bath comprises an organic component selected from film forming polymer molecules such as polymers and copolymers of acrylic, epoxy, polyurethane, phenol-formaldehyde condensation polymers, and mixtures thereof.
• Preferred polymers and copolymers are epoxy; acrylic; and mixtures thereof; most preferably an epoxy- acrylic copolymer.
• Suitable examples of autodeposition compositions useful in the invention include an autodeposition working bath comprising:
• this cross-linker may be comprised of two reactive functional groups of component (a), referred to as internally cross-linking, or may be comprised of a composition reactive with at least one functional group of component (a), referred to herein as externally cross-linking;
• At least one dissolved accelerator component selected from the group consisting of acids, oxidizing agents, and complexing agents that are not part of immediately previously recited components (A) or (B), this accelerator component being sufficient in strength and amount to impart to the total autodepositing liquid composition an oxidation-reduction potential that is at least 100 mV more oxidizing than a standard hydrogen electrode;
• the cross-linker and polymer molecules are selected such that an autodeposition coating on a metal surface resulting from contacting said surface with said working bath cross-links when cured simultaneously with subsequently applied paint layers.
• the autodeposition composition utilizes an epoxy/acrylic binder chemistry where the high molecular weight acrylic segment results in low temperature film formation that is dry to handle with no edge wrinkling and film shrinkage.
• blocked isocyanate external cross-linker is used.
• the amounts of the cross-linker desirably are selected such that it is insufficient to cause film defects as the blocking agent leaves the topcoated system during topcoat curing.
• Suitable amounts of blocked isocyanate when present, are at least in increasing order of preference 0.01 , 0.1, 0.5, 1, 2, 3 or 4%, and are preferably less than in increasing order of preference 15, 13, 1 1, 10, 9, 8, 7, 6, 5% of dried solids and independently preferably, when present, are at least in increasing order of preference 0.01, 0.1, 0.5 or 1% and are less than 6, 5, 4, 3, or 2% of the wet film.
• the uncured autodeposition coatings were dewatered at a range of 121-163 0 C and 138-182 0 C for Aquence® 925G and 915 respectively.
• Aquence® 925G uncured autodeposition coating was topcoated with polyester / Primid powder and the two layers were co-cured at (175 - 225°C).
• Aquence® 915 uncured autodeposition coating was topcoated with polyester/TGI C powder and the two layers were co-cured at 19O 0 C.
• Physical performance measured by cross hatch adhesion, reverse/direct impact, and chip resistance and corrosion performance measured by 500-1000 hours neutral salt spray showed performance consistency throughout the co-cure temperature range.
• the co-cure of autodeposition coatings with powder topcoats offer time and temperature reductions for the dewatering oven.
• the high molecular weight of the polymer allows for film formation and dry to touch coating at low temperature, as well as very low VOC ( ⁇ 0.031b/gallon), small amounts of blocked NCOs, and no other volatile chemicals such as amines.
• a bath composition suitable for coating a metallic substrate by autodeposition at least one of the aforedescribed polymers in aqueous emulsion or dispersion is combined with an autodeposition accelerator component which is capable of causing the dissolution of active metals (e.g., iron and zinc) from the surface of the metallic substrate in contact with the bath composition.
• an autodeposition accelerator component which is capable of causing the dissolution of active metals (e.g., iron and zinc) from the surface of the metallic substrate in contact with the bath composition.
• the amount of accelerator present is sufficient to dissolve at least about 0.020 gram equivalent weight of metal ions per hour per square decimeter of contacted surface at a temperature of 20 °C.
• the accelerator(s) are utilized in a concentration effective to impart to the bath composition an oxidation-reduction potential that is at least 100 millivolts more oxidizing than a standard hydrogen electrode.
• Such accelerators are well-known in the autodeposition coating field and include, for example, substances such as an acid, oxidizing agent, and/or complexing agent capable of causing the dissolution of active metals from active metal surfaces in contact with an autodeposition composition.
• the autodeposition accelerator component may be chosen from the group consisting of hydrofluoric acid and its salts, fluosilicic acid and its salts, fluotitanic acid and its salts, ferric ions, acetic acid, phosphoric acid, sulfuric acid, nitric acid, peroxy acids, citric acid and its salts, and tartaric acid and its salts.
• the accelerator comprises: (a) a total amount of fluoride ions of at least 0.4 g/L, (b) an amount of dissolved trivalent iron atoms that is at least 0.003 g/L, (c) a source of hydrogen ions in an amount sufficient to impart to the autodeposition composition a pH that is at least 1.6 and not more than about 5. Hydrofluoric acid is preferred as a source for both the fluoride ions as well as the proper pH. Ferric fluoride can supply both fluoride ions as ttorney oc et o.
• Accelerators comprised of HF and FeF 3 are especially preferred for use in the present invention.
• ferric cations, hydrofluoric acid, and H 2 O 2 are all used to constitute the autodeposition accelerator component.
• the concentration of ferric cations preferably is at least, with increasing preference in the order given, 0.5, 0.8 or 1.0 g/1 and independently preferably is not more than, with increasing preference in the order given, 2.95, 2.90, 2.85, or 2.75 g/1;
• the concentration of fluorine in anions preferably is at least, with increasing preference in the order given, 0.5, 0.8, 1.0, 1.2, 1.4, 1.5, 1.55, or 1.60 g/1 and independently is not more than, with increasing preference in the order given, 10, 7, 5, 4, or 3 g/1;
• the amount Of H 2 O 2 added to the freshly prepared working composition is at least, with increasing preference in the order given, 0.05, 0.1 , 0.2, 0.3, or 0.4 g/1 and independently preferably is not more than, with increasing preference in the order given,
• a dispersion or coating bath composition of the present invention may also contain a number of additional ingredients that are added before, during, or after the formation of the dispersion.
• additional ingredients include fillers, biocides, foam control agents, pigments and soluble colorants, and flow control or leveling agents.
• the compositions of these various components may be selected in accordance with the concentrations of corresponding components used in conventional epoxy resin-based autodeposition compositions, such as those described in U.S. Pat. Nos. 5,500,460, and 6,096,806.
• Suitable flow control additives or leveling agents include, for example, the acrylic (polyacrylate) substances known in the coatings art, such as the products sold under the trademark MODAFLOW ® by Solutia, as well as other leveling agents such as BYK-310 (from BYK-Chemie), PERENOL ® F-60 (from Henkel), and FLUORAD ® FC-430 (from 3M).
• BYK-310 from BYK-Chemie
• PERENOL ® F-60 from Henkel
• FLUORAD ® FC-430 from 3M.
• Pigments and soluble colorants may generally be selected for compositions according to this invention from materials established as satisfactory for similar uses. Examples of suitable materials include carbon black, phthalocyanine blue, phthalocyanine green, quinacridone red, hansa yellow, and/or benzidine yellow pigment, and the like.
• CRS cold rolled-steel
• Aquence® 925G commercially available from Henkel Corporation
• the uncured autodeposition coated panels were divided into twelve groups and each group was dewatered at a different temperature in a range of 121-163°C for 30 minutes, see Table 1.
• the dewatered panels coated with Aquence® 925G uncured autodeposition coating were topcoated with polyester powder paint from Primid (hydroxyl alkyl amide) and the two layers were co-cured.
• Each of the groups was co-cured at a different temperature in the range of 175 -225 0 C for 18 minutes, see Table 1.
• Chemical co-curing means curing the autodeposition coating/topcoat system at a temperature above the onset of the de-blocking temperature of the blocked NCO in the autodeposition layer.
• the cured coated CRS panels were tested for corrosion and physical performance as shown in Table 1.
• Gravelometer reading of 7A means that the chip diameter is ⁇ 1 mm and number of chips in that range is 10-24. The best possible reading is 8A (same size diameter but ⁇ 10 chips).
• 5B for Crosshatch means 100% adhesion, no loss.
• Direct Impact: 60-80 in. Ib represents initial point of cracks appearing around the rim, no tape adhesion loss observed even at 160 in. Ib (same observation with minor variation seen with all the cure points). Attorney oc et o.
• CRS panels from Q-Lab Corporation were used for the experiment.
• An epoxy acrylic autodeposition bath commercially available from Henkel Corporation was used to deposit an uncured autodeposition coating at -0.7- 0.8 mils thickness on nine groups of panels.
• a black polyester-based powder topcoat available from Akzo Nobel was applied at 2.0 - 3.0 mil thickness.
• the topcoat was polyester (COOH functional) TGIC (triglycidyl isocyanurate) high durable (5-years).
• TGIC triglycidyl isocyanurate
• Cross-linking within powder chains was primarily a COOH - epoxy reaction.
• Cross- linking within autodeposition chains was primarily an OH-NCO urethane reaction.
• Potential chemical interaction between the autodeposition coating layer and topcoat layers at the co-cure interface is NCO from autodeposition with OH from topcoat and/or acid from autodeposition with glycidyl epoxy from powder.
• the autodeposition coating was beginning to chemically cross-link at temperatures of >163°C for the dewatering step.
• the topcoat adhesion began to deteriorate.
• optimum temperature for dewatering for a co-cure system was about 120-150°C. Further reducing the dewatering temperature is also applicable as long as de- watering is achieved.
• fully curing the powder resulted in interlocking of chemistry between the autodeposition coating and the powder paint coating. That is, cross-linking between substances in the autodeposition from coating and substances in the topcoat has taken place as evidenced by improved adhesion.
• an entire vehicle will go through a process of cleaning, autodeposition coating, post-rinsing, and de- watering. Part of the vehicle will then be topcoated while the other part will not, and then the entire vehicle is ovened. Delay and handling between coating and cure of autodeposition has previously been avoided due to performance issues after handling freshly coated parts. This example tests the performance of the portion that will not be topcoated but will be subjected to the two ovens: de- watering and topcoat (co-cure) ovens.
• a co-cure process for autodeposition coatings used in adhesive and sealant applications was tested.
• ACT CRS panels specimen (lab shear) specific for adhesive strength testing were contacted with an autodeposition bath comprising Aquence® 925G, commercially available from Henkel Corporation, for a sufficient time to deposit thereon an uncured autodeposition coating.
• the panels having the uncured autodeposition coating were subjected to a heat treatment such that a pair of panels was uncured (heated at 155°C) and a pair of panels was chemically (i.e. cross-linked by heating) cured (heated at 177 0 C).
• a subsequent layer of commercially available acrylic adhesive (2 component acrylic base) was applied and each pair of orney oc e o.
• Hot Rolled Steel (HRS) panels were used for the study.
• An epoxy acrylic autodeposition coating, Aquence® 930 coating bath, commercially available from Henkel Corporation was used to deposit an uncured autodeposition coating at 0.75-0.85 mils thickness (18-22 ⁇ m).
• a grey polyester TGIC (triglycidyl isocyanurate) powder paint was applied with a combined autodeposition layer- powder layer dry film thickness of 2.5-3.0 mil (62.5-75 ⁇ m).
• a six stage coating process was used to prepare and coat the panels with the autodeposition coating: alkaline cleaner, tap water rinse, DI water rinse, Aquence® 930 autodeposition coating bath, tap water rinse and Aquence® E2 chemical rinse.
• the Aquence® E2 chemical rinse was heated to temperatures varying from 150-160°F and contact time with the chemical rinse was either 2 or 4 minutes for each group of panels.
• the uncured autodeposition coated panels were subjected to 10 minutes in a dehydration oven. Dewatering temperatures for the various groups of panels were either 158, 176, 194, or 212°F, see Table 6.
• polyester TGIC powder was applied to the dewatered autodeposition coating.
• the panels coated with uncured autodeposition coating and uncured powder paint were then subjected to 22 minutes ovening at temperatures of either 325 or 350°F for each group of panels, see Table 6.
• the cured coated HRS panels were tested for physical and corrosion performance as shown in Table 6.

Landscapes

• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Wood Science & Technology (AREA)
• Application Of Or Painting With Fluid Materials (AREA)
• Paints Or Removers (AREA)
• Other Surface Treatments For Metallic Materials (AREA)

Applications Claiming Priority (2)

Publications (2)

Family

ID=40853697

Family Applications (1)

Country Status (6)

Families Citing this family (8)

Family Cites Families (14)

• 2009
  • 2009-01-06 WO PCT/US2009/000045 patent/WO2009088993A2/en active Application Filing
  • 2009-01-06 BR BRPI0906510-5A patent/BRPI0906510A2/pt not_active Application Discontinuation
  • 2009-01-06 EP EP09700628.2A patent/EP2234734A4/de not_active Withdrawn
  • 2009-01-06 CN CN200980104630.0A patent/CN101939115B/zh not_active Expired - Fee Related
  • 2009-01-06 CA CA2733084A patent/CA2733084C/en active Active
  • 2009-01-06 CN CN201410529278.8A patent/CN104289405B/zh not_active Expired - Fee Related
  • 2009-01-06 JP JP2010542258A patent/JP5773653B2/ja not_active Expired - Fee Related

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events