Continuous coiled material pretreatment method

Abstract

Described herein is a continuous web pretreatment process for treating the surface of an aluminum alloy sheet or web for subsequent deposition of an acidic organophosphorus compound. The method may include applying a cleaning agent to a surface of an aluminum sheet or coil; etching the surface of the aluminum sheet or the coil using an acidic solution; washing the surface of the aluminum sheet or the coiled material by using deionized water; coating the surface of the aluminum sheet or the coiled material with a solution of an acidic organophosphorus compound; washing the surface of the aluminum sheet or the coiled material by using deionized water; and drying the surface of the aluminum sheet or the coiled material.

Description

[0001] Divisional Information

[0002] This application is a continuation-in-part of application serial number 201680024321.2, entitled "Continuous Web Pretreatment Method," filed April 29, 2016.

[0003] Cross Reference to Related Applications

[0004] This application claims the benefit of U.S. Provisional Application No. 62 / 155,731, filed May 1, 2015, and U.S. Provisional Application No. 62 / 157,721, filed May 6, 2015, which are incorporated by reference herein in their entirety. TECHNICAL FIELD

[0005] A continuous web pretreatment method is described herein. The method can be used to treat the surface of aluminum sheet and web. BACKGROUND

[0006] Pretreatment refers to surface modification, typically in the form of a thin layer that is coated and converted into a layer via a chemical reaction. The layer imparts characteristics and performance qualities that tend to be significantly different from the bulk of the metal or the metal surface. For example, pretreatment can provide improved adhesive bonding performance and improved corrosion resistance compared to non-pretreated surfaces. New pretreatment methods are needed to further improve these and other characteristics and to produce pretreated surfaces in an efficient and reliable manner. SUMMARY

[0007] The embodiments encompassed by the application are defined by the claims, not this summary. This summary is a high-level overview of various aspects of the application and introduces some of the concepts further described in the detailed description section below. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it meant to be used in determining the scope of the claimed subject matter. The subject matter should be understood from reading the entire specification, with appropriate sections of the description, including any claims, drawings, and drawings, taken together with the entire specification.

[0008] A continuous coil pretreatment method is provided herein. The continuous coil pretreatment method as described herein comprises a) applying a cleaner to a surface of an aluminum sheet or coil; b) etching a surface of the aluminum sheet or the coil using an acidic solution; c) rinsing a surface of the aluminum sheet or the coil using deionized water; d) applying a solution of an acidic organophosphorus compound to a surface of the aluminum sheet or the coil; e) rinsing a surface of the aluminum sheet or the coil using deionized water; and f) drying a surface of the aluminum sheet or the coil. The acidic organophosphorus compound can be a vinylphosphonic acid-acrylic acid copolymer or A951. The concentration of the acidic organophosphorus compound can be from about 0.4 wt% to about 10 wt% (e.g., from about 0.6 wt% to about 5 wt%, from about 0.7 wt% to about 3 wt%, or from about 0.8 wt% to about 1.0 wt%). The acidic solution can comprise sulfuric acid at a concentration of from about 2 vol% to about 15 vol%. Optionally, the acidic solution comprises sulfuric acid, sulfuric acid and hydrofluoric acid, nitric acid, and / or phosphoric acid. The deionized water in step (c) can optionally have a conductivity of less than or equal to 25 uS / cm.

[0009] The aluminum sheet or coil can be made from an aluminum alloy selected from the group consisting of 1XXX alloys, 2XXX alloys, 3XXX alloys, 4XXX alloys, 5XXX alloys, 6XXX alloys, and 7XXX alloys. Optionally, the aluminum sheet or coil is made from an aluminum alloy selected from the group consisting of AA5754 alloy, AA5182 alloy, AA6451 alloy, AA6111 alloy, and AA6014 alloy. The cleaner in step (a) can comprise hot water. The cleaner in step (a) can also comprise an acid, a base, a surfactant, or a detergent. The applying step in step (d) can be performed by soaking the aluminum sheet or the coil in the solution of the acidic organophosphorus compound or by spray coating the aluminum sheet or the coil with the solution of the acidic organophosphorus compound.

[0010] Optionally, step (b) can be performed by applying a spray of the acidic solution. The acidic solution in contact with the surface of the aluminum sheet or coil in step (b) can comprise less than about 1000 ppm of aluminum ions and magnesium ions. Optionally, the solution of the acidic organophosphorus compound in contact with the surface of the aluminum sheet or coil in step (d) comprises no more than about 80 ppm of aluminum ions.

[0011] An aluminum sheet or coil treated according to the method as described herein is also described herein.

[0012] Also described herein is a continuous coil pretreatment method comprising a) applying a cleaner to a surface of an aluminum sheet or coil by hot water jet impact; b) etching the surface of the aluminum sheet or the coil using an acidic solution, optionally in combination with a surfactant additive or accelerator, at a temperature of about 55 °C to about 85 °C for a time of about 5 seconds to about 15 seconds; c) rinsing the surface of the aluminum sheet or the coil using deionized water at a temperature of about 37 °C to about 70 °C; d) applying a solution of an acidic organophosphorous compound to the surface of the aluminum sheet or the coil at a temperature of about 45 °C to about 85 °C for a time of about 5 seconds to about 20 seconds; e) rinsing the surface of the aluminum sheet or the coil with deionized water immediately after or after about 1 second to about 5 seconds after applying the acidic organophosphorous compound; and f) drying the surface of the aluminum sheet or the coil.

[0013] Other objects and advantages of the application will be apparent from the following detailed description of non-limiting embodiments of the application. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1A is a three-dimensional scatter plot of X-ray fluorescence (XRF) phosphorus values plotted against etch (R243) and pretreatment (A951) residence times. Figure 1B is a surface plot of XRF phosphorus values plotted against etch (R243) and pretreatment (A951) residence times.

[0015] Figure 2A is a three-dimensional scatter plot of X-ray fluorescence (XRF) phosphorus values plotted against etch (R243) and pretreatment (A951) residence times. Figure 2B is a surface plot of XRF phosphorus values plotted against etch (R243) and pretreatment (A951) residence times.

[0016] Figure 3A is a graph showing the effect of acid etch residence time on the phosphorus coating weight of the final aluminum sheet. Figure 3B is a graph showing the effect of organophosphorous pretreatment residence time on the phosphorus coating weight of the final aluminum sheet. DETAILED DESCRIPTION

[0017] Provided herein are continuous coil pretreatment methods. The continuous coil pretreatment methods as described herein include a) applying a cleaner to a surface of an aluminum sheet or coil; b) etching a surface of the aluminum sheet or the coil using an acidic solution; c) rinsing a surface of the aluminum sheet or the coil using deionized water; d) applying a solution of an acidic organophosphorus compound to a surface of the aluminum sheet or the coil; e) rinsing a surface of the aluminum sheet or the coil using deionized water; and f) drying a surface of the aluminum sheet or the coil. Optionally, the continuous coil pretreatment methods as described herein include a) applying a cleaner to a surface of an aluminum sheet or coil by hot water jet impact; b) etching a surface of the aluminum sheet or the coil at a temperature of about 55 °C to about 85 °C for a time of about 5 seconds to about 15 seconds using an acidic solution, optionally in combination with a surfactant additive or accelerator; c) rinsing a surface of the aluminum sheet or the coil at a temperature of about 37 °C to about 70 °C using deionized water; d) applying a solution of an acidic organophosphorus compound to a surface of the aluminum sheet or the coil at a temperature of about 45 °C to about 85 °C for a time of about 5 seconds to about 20 seconds; e) rinsing a surface of the aluminum sheet or the coil with deionized water immediately after or after about 1 second to about 5 seconds after applying the acidic organophosphorus compound; and f) drying a surface of the aluminum sheet or the coil.

[0018] Aluminum sheets or coils treated with the methods as described herein have particularly robust and durable surfaces when exposed to, for example, accelerated adhesive stress durability testing in corrosive environments. Further, the methods as described herein provide a robust and repeatable production method that can be evidenced by the pretreatment coating weight on aluminum sheets or coils and the stability of the coating weight.

[0019] Definitions and Descriptions

[0020] The terms "invention," "the invention," "this invention," and "the present invention" used herein are intended to refer broadly to all of the subject matter of this patent application and the following claims and should be construe

[0021] In this specification, reference is made to alloys identified by AA designations and other related nomenclature, such as "series". For an understanding of the designation system most commonly used for naming and identifying aluminum and its alloys, see "International Alloy Designations and Chemical Composition Limits for Wrought Aluminum and Wrought Aluminum Alloys" or "Registration Record of Aluminum Association Alloy Designations and Chemical Compositions Limits for Aluminum Alloys in the Form of Castings and Ingot", both published by The Aluminum Association.

[0022] The meaning of "a," "an," and "the" as used herein includes singular and plural referents unless the context clearly dictates otherwise.

[0023] Continuous web pretreatment process

[0024] A continuous coil pretreatment method is described herein for treating the surface of an aluminum alloy sheet or coil for the subsequent deposition of a pretreatment agent, such as an organophosphorous compound. The method can be used on many aluminum alloys including, but not limited to, 1XXX alloys, 2XXX alloys, 3XXX alloys, 4XXX alloys, 5XXX alloys, 6XXX alloys, and 7XXX alloys. For example, the method described herein can be used on AA5754 alloys, AA5182 alloys, AA6451 alloys, AA6111 alloys, AA6014 alloys, x608 alloys, x615 alloys, x616 alloys, and x621 alloys. The method described herein can be used in a continuous coil pretreatment method using coils that are spliced or joined together. The line speed of the continuous coil pretreatment method is variable and can be determined by one skilled in the art. Optionally, the line speed can be in the range of 15 meters per minute - 100 meters per minute (mpm). For example, the line speed can be 15 mpm, 20 mpm, 25 mpm, 30 mpm, 35 mpm, 40 mpm, 45 mpm, 50 mpm, 55 mpm, 60 mpm, 65 mpm, 70 mpm, 75 mpm, 80 mpm, 85 mpm, 90 mpm, 95 mpm, or 100 mpm.

[0025] Inlet cleaner

[0026] The continuous coil pretreatment method described herein includes the step of applying a cleaner, also referred to herein as an entry cleaner, to the surface of an aluminum sheet or coil. The entry cleaner removes residual oils or loosely adhered oxides from the surface of the sheet or coil. Optionally, the entry cleaning can be performed using a hot water spray impact. Optionally, the entry cleaning can be performed using a solvent or mixture of solvents, such as hexane, ethanol, acetone, and combinations of these. Optionally, one or more additives can be combined with the hot water to improve the efficiency of the entry cleaner. For example, the hot water can be modified to improve its efficiency by the addition of an acid or base and / or a surfactant / detergent.

[0027] To avoid accumulation of entrained oils or oxides in the inlet cleaner, the inlet cleaner can be periodically replaced or replenished. Optionally, the oils and oxides in the inlet cleaner can be periodically purged using, for example, a suitable oil separator or filter. The use of an inlet cleaner can provide a synergistic etch response when combined with an acid etch step as described below. The use of an inlet cleaner can also be beneficial when used in combination with a pre-treatment process step as described below. In some cases, when the inlet cleaner step is omitted, any residual oils present will be exposed to the high temperature heat treatment, which can cause the oils to burn on the surface of the sheet. Such burned oils are difficult to remove using an etching process; therefore, the oils should be removed prior to heat treatment and prior to the etching process.

[0028] Acid etch

[0029] The continuous web pre-treatment process described herein also includes a step of etching the surface of the aluminum sheet or the web. An acid etch (i.e., an etching process including an acidic solution) can be used to etch the surface of the aluminum sheet or web. The acid etch prepares the surface for subsequent coating with a pre-treatment agent. Any loosely adhered oxides, such as Al oxides and Mg-rich oxides, entrained oils, or debris should be substantially removed during this step.

[0030] Exemplary acids for performing the acid etch include sulfuric acid, hydrofluoric acid, nitric acid, phosphoric acid, and combinations of these. Optionally, the acid etch solution can include one or more additives (e.g., a surfactant additive) and / or one or more accelerators. Suitable surfactant additives include polyoxyalkylene oxides. A surfactant additive can be included in the acid etch solution at a concentration ranging from about 0.1 vol% to 10 vol%. For example, a surfactant additive can be included in the acid etch solution at a concentration ranging from about 0.5 vol% to 9 vol%, from about 1 vol% to 8 vol%, from about 1.5 vol% to 7 vol%, from about 2 vol% to 6 vol%, or from about 3 vol% to 5 vol%. Optionally, a surfactant additive can be included ranging from 1 vol% to 5 vol%. Suitable accelerators that can be included in the acid etch solution include ferric sulfate. An accelerator can be included in the acid etch solution at a concentration ranging from about 0.05 vol% to 4 vol%. For example, an accelerator can be included in the acid etch solution at a concentration ranging from about 0.06 vol% to 3 vol%, from about 0.07 vol% to 2 vol%, or from about 0.1 vol% to 1 vol%.

[0031] Optionally, the acid etching solution can be provided as a commercially available pre-mixed solution. For example, a suitable acid etching solution containing sulfuric acid along with a surfactant additive (e.g., polyoxyalkylene) and an accelerator (e.g., ferric sulfate) can be pre-mixed and used as the acid etching solution. Optionally, the acid etching solution can be RIDOLINE 243, an acid etching solution commercially available from Henkel AG (Dusseldorf, Germany).

[0032] The acid etching solution can be heated to a temperature of about 55 °C to about 85 °C prior to use. For example, the acid etching solution can be heated to about 55 °C, 60 °C, about 65 °C, about 70 °C, about 75 °C, about 80 °C, or about 85 °C. The acid etching solution can be used at a concentration range of about 1% to about 15% (volume% of acid based). For example, the concentration of the acid etching solution can be about 1.5% to about 10%, about 1.5% to about 8%, about 1.5% to about 5%, about 2% to about 4%, or less than about 5% volume% of acid based. Optionally, the acid is used in an amount of about 2.5 volume%. The concentration can be measured by titration procedure of free acid and total acid or by inductively coupled plasma (ICP). For example, in an acid etching solution containing sulfuric acid, the sulfur concentration can be measured using ICP. The sulfur concentration in such an acid etching solution can be in a range of about 6000 ppm to 12000 ppm. The acid etching solution can be controlled within the outlined temperature and concentration ranges using, for example, a heat exchanger and a metering pump along with an overflow and appropriately replaced or replenished.

[0033] The acid etching solution can be applied by roll coating the solution onto the sheet, by spraying the solution onto the sheet, or by soaking the sheet or a portion of the sheet (e.g., the sheet surface) in a bath. Optionally, the acid etching solution can be circulated to ensure that fresh solution is continuously exposed to the sheet surface. The residence time of the acid etching can be about 5 seconds to about 15 seconds. For example, the residence time of the acid etching can be about 5 seconds, about 6 seconds, about 7 seconds, about 8 seconds, about 9 seconds, about 10 seconds, about 11 seconds, about 12 seconds, about 13 seconds, about 14 seconds, or about 15 seconds.

[0034] As a reaction byproduct from the etching step, the acid etch solution can contain less than 1,000 ppm of aluminum (Al) ions and magnesium (Mg) ions. In some embodiments, the acid etch solution contains 300 ppm or more of Al ions and Mg ions, in total or separately. Optionally, the acid etch solution contains 300 ppm, 400 ppm, 500 ppm, 600 ppm, 700 ppm, 800 ppm, 900 ppm, or 1,000 ppm of Al ions and Mg ions, in total. Theoretically, lower levels of these two cations are preferred and result in a cleaner surface that is more highly etched. Optionally, all oil can be continuously separated from the acid using an oil separation loop and associated filters to remove any debris buildup.

[0035] Rinse after acid etch

[0036] After the acid etching step, the surface of the aluminum sheet or web is rinsed with a solvent. Optionally, the solvent can be an aqueous solution, such as deionized (DI) water or reverse osmosis (RO) water. The rinsing step can be performed at a temperature ranging from about 37 °C to about 70 °C. For example, the rinsing step can be performed at a temperature of about 40 °C to about 65 °C, about 45 °C to about 60 °C, or about 50 °C to about 55 °C.

[0037] The rinsing can be a progressive cascade system. Optionally, the rinsing step is performed using a showerhead. In some cases, the final rinse can use fresh (i.e., unused or non-recirculated) deionized water having a conductivity of 25 uS / cm or less (e.g., 20 uS / cm or less, 15 uS / cm or less, 10 uS / cm or less, or 5 uS / cm or less). In these cases, a solvent film break surface (e.g., a water film break surface) can be created. A water film break surface means that when the surface is subsequently wetted with water, it flows uniformly across the surface without retracting (i.e., being repelled) or forming areas with little to no solution in them.

[0038] Application of pretreatment

[0039] An organophosphorous pretreatment, such as an acidic organophosphorous pretreatment, can then be applied to the surface of the aluminum sheet or web. The pretreatment can be applied at a temperature of about 45 °C to about 85 °C. For example, the pretreatment can be applied at a temperature of 45 °C, 50 °C, 55 °C, 60 °C, 65 °C, 70 °C, 75 °C, 80 °C, or 85 °C. The pretreatment can be applied for a time of about 5 seconds to about 20 seconds. For example, the pretreatment can be applied for 5 seconds, 6 seconds, 7 seconds, 8 seconds, 9 seconds, 10 seconds, 11 seconds, 12 seconds, 13 seconds, 14 seconds, 15 seconds, 16 seconds, 17 seconds, 18 seconds, 19 seconds, or 20 seconds.

[0040] Suitable acidic organophosphorus compounds for use as a pretreatment agent include vinyl phosphonic acid (VPA)-acrylic acid copolymers. For example, the acidic organophosphorus compound can be A951 (also known as Alcoa 951P or Alcoa 951C), which is available from Chemetall (New Providence, NJ). The pretreatment agent can optionally include other blends of VPA and polymeric additives.

[0041] Coating of the pretreatment agent on the surface of the aluminum sheet or web results in a thin layer of organophosphorus compound, such as A951. For example, the coating of the pretreatment agent on the surface of the aluminum sheet or web provides a very thin monolayer of pretreatment agent molecules, which can optionally be equivalent to 0.4 mg / m2 / side to 7 mg / m2 / side of P. Optionally, the pretreatment agent monolayer can be 0.1 nm to 20 nm thick (e.g., 0.5 nm to 15 nm or 1 nm to 10 nm thick).

[0042] The acidic organophosphorus pretreatment agent can be coated by roll coating the sheet or web with a solution containing the pretreatment agent, by spray coating the sheet or web with a solution containing the pretreatment agent, or by soaking the sheet or web in a solution containing the pretreatment agent. The solution containing the pretreatment agent can contain about 0.01 wt% to 10.0 wt% of the pretreatment agent. For example, the pretreatment agent can be present in the solution containing the pretreatment agent in an amount of about 0.01 wt% to 9.0 wt%, 0.05 wt% to 8.0 wt%, 0.1 wt% to 7.0 wt%, 0.2 wt% to 6.0 wt%, 0.3 wt% to 5.0 wt%, 0.5 wt% to 4.0 wt%, about 1.0 wt% to 3.0 wt%, or about 1.5 wt% to 2.5 wt%. Optionally, the concentration of the pretreatment agent can be in the range of 0.4 wt% to 10.0 wt%, 0.6 wt% to 5.0 wt%, or 0.7 wt% to 3.0 wt%. In some embodiments, the amount of pretreatment agent present in the solution can be in the range of 0.8 wt% to 1.0 wt%. The concentration of components in the pretreatment solution can be measured according to techniques as known by those skilled in the art, such as by titration procedures for free acid and total acid or by ICP. For example, the phosphorus content can be measured by ICP. Optionally, the phosphorus content can be in the range of about 2250 ppm to about 2750 ppm (e.g., about 2300 ppm to about 2700 ppm, about 2350 ppm to about 2650 ppm, or about 2400 ppm to about 2600 ppm).

[0043] The pre-treatment solution can optionally contain aluminum (Al) ions as a result of the solution contacting the surface of the aluminum sheet or coil. The Al ions can be a reaction byproduct of the pre-treatment agent. Optionally, the amount of Al ions in the solution contacting the surface of the aluminum sheet or coil is 80 ppm or less. For example, the solution contacting the surface of the aluminum sheet or coil can contain less than 75 ppm Al ions, less than 70 ppm Al ions, less than 65 ppm Al ions, less than 60 ppm Al ions, less than 55 ppm Al ions, less than 50 ppm Al ions, less than 45 ppm Al ions, less than 40 ppm Al ions, or less than 35 ppm Al ions.

[0044] The pre-treatment solution can optionally contain magnesium (Mg) ions. Optionally, the amount of Mg ions in the solution contacting the surface of the aluminum sheet or coil is 45 ppm or less. For example, the solution contacting the surface of the aluminum sheet or coil can contain less than 40 ppm Mg ions, less than 35 ppm Mg ions, less than 30 ppm Mg ions, less than 25 ppm Mg ions, less than 20 ppm Mg ions, less than 15 ppm Mg ions, less than 10 ppm Mg ions, or less than 5 ppm Mg ions.

[0045] Optionally, overflow and replenishment means can be provided to maintain chemical concentrations and Al ion levels.

[0046] Iron (Fe) is known to have an adverse effect on the cohesiveness of some pre-treatment agents, including A951. Fe should be maintained in the bath below 30 ppm and checked periodically by ICP (ICP Inc.). For example, the Fe level can be maintained below 25 ppm, below 20 ppm, below 15 ppm, below 10 ppm, or below 5 ppm.

[0047] Rinse after application of pretreatment

[0048] After coating the pre-treatment agent, the surface of the aluminum sheet or the coil can be rinsed with a solvent. Suitable solvents include aqueous solvents (e.g., deionized water). The rinse removes any unattached or unreacted pre-treatment agent (e.g., A951) that is not firmly attached to the surface of the aluminum sheet or coil. The rinse can occur up to 5 seconds after coating the pre-treatment agent. For example, the rinse can occur immediately after pre-treatment agent coating, or with a delay of about 1 second to about 5 seconds after pre-treatment agent coating. Desirably, deionized water can be used to take advantage of a sequential cascading rinse system, where the final rinse fluid has a conductivity of 25 uS / cm or less.

[0049] The final rinse can be performed using a showerhead or by immersion. In either case, the deionized water must be properly circulated to remove unattached pretreatment from the surface and prevent it from reattaching to the surface. The final rinse solution must be substantially free of pretreatment (e.g., A951) to avoid any previously rinsed off pretreatment from depositing back onto the surface. The final rinse solution must contain a minimum amount of pretreatment such that the conductivity is about 200 uS / cm or less (e.g., 175 uS / cm or less, 150 uS / cm or less, 125 uS / cm or less, or 100 uS / cm or less).

[0050] The temperature of the rinse solvent is not particularly important, so long as water is sufficiently removed from the surface. Optionally, the rinse solvent can be at a temperature of about 20 °C to about 70 °C.

[0051] As described above, the final rinse can be performed using a showerhead. When a showerhead is used, the direction of the spray is important and should flow in a direction opposite to the sheet direction. Any showerhead known to one of ordinary skill in the art can be used. A non-limiting example of a suitable showerhead is a halo showerhead (umbrella-like scattering microshowerhead).

[0052] Pretreatment can be transferred via the rinse water to the exit blanket roll and thus "reprint" the pretreatment onto the exiting sheet surface. A "water barrier" at the entrance to the blanket roll is an effective means of preventing pretreatment or pretreatment gel or sediment from coming into contact with the blanket roll surface and the showerhead that continuously rinses the blanket roll surface.

[0053] Dryer after rinse

[0054] After the rinsing step, the surface of the aluminum sheet or the web can be dried. The drying step removes any rinse water from the surface of the sheet or the web. The drying step can be performed using an air dryer or by an infrared dryer. The drying step can be performed for a period of time of up to five minutes. For example, the drying step can be performed for 5 seconds or more, 10 seconds or more, 15 seconds or more, 20 seconds or more, 25 seconds or more, 30 seconds or more, 35 seconds or more, 40 seconds or more, 45 seconds or more, 50 seconds or more, 55 seconds or more, 60 seconds or more, 65 seconds or more, or 90 seconds or more. Optionally, the drying step can be performed for 2 minutes or more, 3 minutes or more, 4 minutes or more, or 5 minutes. Optionally, the drying step can be performed for more than 5 minutes. A curing step or chemical reaction can optionally be performed, but this is not necessary.

[0055] Test conditions and / or controls

[0056] All chemicals should be controlled by careful measurement, such as ICP, titration, conductivity meter, pH meter, flow meter, and X-ray fluorescence (XRF) detection of the pretreatment agent on the surface of the sheet or web.

[0057] Re-rinse test

[0058] Measuring the change in phosphorous coating weight after hot water extraction can be used to determine if the pretreatment coating has been effectively and completely chemisorbed onto the substrate. The procedure involves measuring the sample pan with XRF and obtaining the phosphorous coating weight. The pan can then be rinsed with a solvent, such as hexane, to remove any dry film lubricant. The sample can then be placed into a vessel containing deionized water or reverse osmosis (RO) water at an elevated temperature, such as 80°C to 85°C. The sample can then be removed, dried by using a warm air dryer, and placed into the XRF unit to remeasure the phosphorous coating weight. The initial coating weight is subtracted from the post-rinse coating weight to determine the difference. A difference of less than 10% is considered suitable for a substrate treated with the pretreatment agent. At values higher than 10%, poor durability is often observed, while when the post-rinse value is less than 10%, the durability is suitable.

[0059] The following examples will serve to further illustrate the present application, but are not to be construed as in any way limiting its scope. On the contrary, it will be apparent that various modifications, both as to the nature of the embodiment and equivalents thereof, can be resorted to by those skilled in the art, having the benefit of the teachings herein without departing from the spirit and scope of the application.

[0060] Example 1

[0061] The surface of aluminum alloy sheet was treated according to the methods described herein. The sheet used in the examples included alloy 5754 sheet (2 mm gauge); alloy 6111 sheet (1 mm gauge); and alloy 5182 sheet (1.34 mm gauge). The sheet was cleaned and acid etched by spraying Ridoline 243 (R243) heated to 65°C at a flow rate of 257 L / min and at a pressure of 2.0 bar. The acid etch dwell time was varied and is shown in Table 1 below.

[0062] The sheet was then rinsed with deionized water as described herein and coated with organophosphorus compound by soaking the sheet in a 1 wt% solution of A951 at 65°C or spraying the sheet with a 1 wt% solution of A951 at 65°C at a flow rate of 255 liters / minute and at a pressure of 2.5 bar (different is that Example 27 was sprayed at a pressure of 3.5 bar). The organophosphorus residence time is sometimes referred to herein as the pretreatment residence time. The Al ions present in the A951 solution at the beginning and end of the soaking process are shown in Table 2. The residence time of the soaking was varied and is shown in Table 1 below. The sheet was then rinsed using hot deionized water to remove any unattached or unreacted A951.

[0063] Table 1

[0064]

[0065]

[0066] The level of aluminum ions in the organophosphorus solution at the beginning and end of the coating process was measured. The change in phosphorus coating weight was also measured according to the method described above. Specifically, the phosphorus coating weight was measured by XRF of the top surface of the sheet and the bottom surface of the sheet before and after rinsing with hot deionized water. The results are shown in Table 2.

[0067] Table 2

[0068]

[0069]

[0070] Effect of Al ion level in organophosphorus solution on coating weight (Examples 1-6)

[0071] The effect of the Al ion level in the organophosphorus solution used to pretreat the aluminum sheet on the final phosphorus coating weight was determined. Example 1 and Example 4 included a 32 second residence time for both the acid etching step and the organophosphorus soaking step. The phosphorus coating weight for these samples was about 9 mg / m 2 -10 mg / m 2 . Example 2 and Example 5 included a 5 second residence time for both the acid etching step and the organophosphorus soaking step. The phosphorus coating weight for these samples was about 4 mg / m 2 -5 mg / m 2 . Example 3 and Example 6 included a 2.5 second residence time for both the acid etching step and the organophosphorus soaking step. The phosphorus coating weight for these samples was about 3 mg / m 2 -4 mg / m 2As shown by these examples, shortening the dwell time for acid etching and organic phosphorus immersion results in lower phosphorus coating weights. However, increasing the Al level in the organic phosphorus solution (e.g., from 0 ppm to about 10 ppm) has no effect on the phosphorus coating weight.

[0072] Effect of organic phosphorus solution coating method on coating weight (Examples 4-9)

[0073] The effect of the method of applying the organic phosphorus solution to the aluminum sheet on the final phosphorus coating weight was determined. Examples 4-6 were prepared by immersing the sheet in the organic phosphorus solution, while Examples 7-9 were prepared by spraying the sheet with the organic phosphorus solution. When using shorter pre-treatment times of 2.5 seconds to 5 seconds (Examples 5-6 and 8-9), the phosphorus coating weights produced using the immersion method and the spray method were similar. However, at longer pre-treatment times (e.g., 32 seconds; Example 4 and Example 7), differences in phosphorus coating weight were shown only on the top surface. The top surface tended to have a lower coating weight.

[0074] Effect of acid etching time on phosphorus coating weight (Examples 7-13 and 15)

[0075] The effect of acid etching time on the final phosphorus coating weight was determined. Higher coating weights were obtained using longer acid dwell times (e.g., 32 seconds, as shown in Example 7, Example 13, and Example 15) compared to shorter dwell times (e.g., 2.5 seconds, 5.0 seconds, or 16.0 seconds, as shown in Examples 8-12).

[0076] Effect of alloy type on coating weight (Examples 16-19 and 21)

[0077] Suitable phosphorus coating weights were obtained on alloy types including alloy 6111 (see Examples 16-18) and alloy 5182 (see Examples 19 and 21) in addition to alloy 5754. For 6111 alloy, a 1.7 mg / m 2 to 3 mg / m 2 phosphorus coating weight can be obtained by using an etch / pre-treatment dwell time of 5 seconds. For 5182 alloy, a 4.7 mg / m 2 to 5.7 mg / m 2 phosphorus coating weight can be obtained by using a combination of an acid etch dwell time of 2.5 seconds and a pre-treatment dwell time of 5 seconds.

[0078] Effect of Al level on phosphorus coating weight under immersion method (Examples 1-6 and 22-24)

[0079] Examples 1-6 were prepared using an organophosphorus solution (A951 solution) containing 0 ppm to 17 ppm Al. Examples 22-24 were prepared using an organophosphorus solution containing 34 ppm to 37 ppm Al. As shown in Table 2, when in an immersion manner, the Al level of 0 ppm to 17 ppm in A951 had no significant effect on the weight of the phosphorus coating for a given residence time. However, for a given residence time, an Al level of 34 ppm to 37 ppm reduced the weight of the phosphorus coating. The effect was greater when using an immersion manner and with a longer residence time at a high Al level (e.g., 34 ppm to 37 ppm). The effect is shown in... Figure 1A and Figure 1B In the middle, the Figure 1A This is a three-dimensional scatter plot of XRF phosphorus values ​​relative to the dwell time of etching and pretreatment. Figure 1B This is a surface plot of XRF phosphorus values ​​relative to the dwell time of etching and pretreatment.

[0080] The effect of Al level on the weight of phosphorus coating under spraying method (Examples 7-15 and 25-27)

[0081] Examples 7-15 were prepared using an organophosphorus solution (A951 solution) containing 17 ppm to 21.6 ppm Al. Examples 25-27 were prepared using an organophosphorus solution containing more than 30 ppm Al. As shown in Table 2, the phosphorus coating under spraying conditions was not as significantly affected by the Al level as the sheet under immersion conditions. With longer dwell times for etching and pretreatment (e.g., 32 seconds), the weight of the phosphorus coating on the bottom surface decreased slightly when the Al level in the A951 solution increased from about 19 ppm to 30 ppm (compare Examples 7 and 25). Using a 5-second dwell time for etching and pretreatment, the weight of the phosphorus coating decreased slightly when the Al level increased from 19 ppm to 30 ppm (compare Examples 8 and 26). These effects are shown in... Figure 2A and Figure 2B In the middle, the Figure 2A This is a three-dimensional scatter plot of XRF phosphorus values ​​relative to the dwell time of etching and pretreatment. Figure 2B This is a surface plot of XRF phosphorus values ​​relative to the dwell time of etching and pretreatment.

[0082] Effect of residence time in acid or organophosphorus pretreatment steps

[0083] like Figure 3A and Figure 3B As shown in the figure, the dwell time during the acid etching step and the organophosphorus pretreatment step affects the phosphorus coating weight of the final sheet.

[0084] Stress durability test results (Examples 1-3, 7-9, 13-15, and 18)

[0085] The stress durability test was performed on the sheets prepared as described above. In the stress durability test, a set of 6 lap joints were connected in series by bolts and placed vertically in a 100% relative humidity (RH) humidity chamber. The temperature was maintained at 50°C ± 2°C. A tensile load of 2.4 kN was applied to the joint sequence. The stress durability test is a cyclic exposure test performed for up to 45 cycles. Each cycle lasted 24 hours. In each cycle, the joints were exposed in the humidity chamber for 22 hours, then immersed in 5% NaCl for 15 minutes, and finally air dried for 105 minutes. The test was discontinued for a particular set of joints when three joints had broken. Completion of 45 cycles indicated that the set of joints passed the joint durability test. The results are shown in Table 3. In Table 3, each of the joints was numbered 1 to 6, where joint 1 is the top joint and joint 6 is the bottom joint when oriented vertically.

[0086] Table 3

[0087]

[0088] Suitable values were obtained for all samples except Example 1 which had a coating weight of 9 mg / m2P. 2 - 10 mg / m2P 2 Suitable values were obtained for all samples except Example 1 which had a coating weight of 9 mg / m2P.

[0089] All patents, publications, and abstracts cited above are incorporated herein by reference in their entirety. Various embodiments of the application have been described in fulfillment of various objects of the application. It should be recognized that these embodiments are merely illustrative of the principles of the present application. Numerous modifications and adaptations thereof will be apparent to those skilled in the art without departing from the spirit and scope of the present application as defined in the following claims.

Claims

1. A method for pre-treating continuous roll materials, comprising: (a) Apply cleaning agent to the surface of aluminum sheet; Then (b) Removing at least some surface material from the surface of the aluminum sheet, wherein the surface material includes at least one of oxides, entrained oil, and debris, and wherein the removal includes applying an etchant to the surface of the aluminum sheet; then (c) Rinse the surface of the aluminum sheet with a solvent to create a non-breakable water film; then (d) Apply the pretreatment to the non-breakable surface of the water film on the aluminum sheet; The pretreatment mentioned above includes a vinylphosphonic acid-acrylic acid copolymer, and The application step includes: (i) forming a monolayer of the vinylphosphonic acid-acrylic acid copolymer on the aluminum sheet; then (e) Remove at least some of the excess vinylphosphonic acid-acrylic acid copolymer from the aluminum sheet; The removal includes applying a solvent to the monolayer of the vinylphosphonic acid-acrylic acid copolymer, and The excess vinylphosphonic acid-acrylic acid copolymer mentioned above includes unattached vinylphosphonic acid-acrylic acid copolymer; then (f) Dry the surface of the aluminum sheet.

2. The continuous roll pretreatment method according to claim 1, wherein the surface material comprises aluminum oxide.

3. The continuous roll pretreatment method according to claim 1, wherein the rinsing step (c) is immediately following the removal step (b), and wherein the application step (d) is immediately following the rinsing step (c).

4. The continuous roll pretreatment method according to claim 3, wherein the rinsing step (c) includes cascade rinsing, wherein the solvent includes water, and wherein the rinsing includes a final rinsing step, wherein the final rinsing step includes applying deionized water having a conductivity of 25 μS / cm to the surface of the aluminum sheet.

5. The continuous roll pretreatment method according to claim 1, wherein the forming step (d)(i) comprises reacting at least some of the vinylphosphonic acid-acrylic acid copolymer with the surface of the aluminum sheet to form the monolayer.

6. The continuous roll pretreatment method according to claim 5, wherein the pretreatment comprises 0.1% to 10% by weight of vinylphosphonic acid-acrylic acid copolymer.

7. The continuous roll pretreatment method according to claim 6, wherein the pretreatment comprises 0.2% to 6.0% by weight of vinylphosphonic acid-acrylic acid copolymer.

8. The continuous roll pretreatment method according to claim 7, wherein the single layer achieves 0.4 mg P / m 2 Up to 0.7 mg P / m 2 The weight of the phosphorus coating.

9. The continuous roll pretreatment method according to claim 8, wherein the water film-free surface is a first water film-free surface located on a first side of the aluminum sheet, wherein the monolayer is a first monolayer, and wherein the application step (d) comprises forming a second monolayer on a second side of the aluminum sheet by a vinylphosphonic acid-acrylic acid copolymer, wherein both the first monolayer and the second monolayer achieve 0.4 mg P / m 2 Up to 0.7 mg P / m 2 The weight of the phosphorus coating.

10. The continuous roll pretreatment method according to claim 9, wherein at least one of the first monolayer and the second monolayer has a thickness of 0.1 nm to 20 nm.

11. The continuous roll pretreatment method according to claim 1, wherein the etchant comprises at least one selected from sulfuric acid, hydrofluoric acid, nitric acid, and phosphoric acid.

12. The continuous roll pretreatment method according to claim 11, wherein the etchant comprises 0.1% to 10% by weight of sulfuric acid.

13. The continuous roll pretreatment method according to claim 11, wherein the etchant comprises aluminum ions of no more than 1000 ppm.

14. The continuous roll pretreatment method according to claim 13, wherein the etchant comprises magnesium ions of no more than 1000 ppm.

15. The continuous roll pretreatment method according to claim 14, wherein the removal step (e) occurs within approximately 5 seconds of the application step (d).

16. The continuous roll pretreatment method according to claim 14, wherein the etchant comprises at least one of a surfactant and an accelerator.

17. The continuous coil pretreatment method according to claim 1, wherein the aluminum sheet is one of 5XXX and 6XXX aluminum alloys.

18. The continuous coil pretreatment method according to claim 1, wherein the aluminum sheet is one of AA5754, AA5182, AA6451, AA6111 and AA6014 aluminum alloys.

19. The continuous roll pretreatment method according to claim 1, wherein the aluminum sheet is in a wound form prior to the application step (a).

20. The continuous roll pretreatment method according to claim 19, comprising rewinding the aluminum sheet after the drying step (f).

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