KR900000419B1 - Dry lubricant for drawing steel plate - Google Patents

Abstract

Metal substrates are coated prior to multiple forming operations with a thin film of an adhesion-retaining vinyl, epoxyphenolic, or epoxy- urea-formaldehyde resin contg. 0.5-6% of its wt. of a dry film lubricant comprising polyethylene wax or carnauba wax, having a m.p. which is higher than that of the coating resin; The latter is cured by heating to give a coating having softening point at least 85 ≰C. Addition of the lubricant provides a coating having increased lubricity and resistance to scuffing during high speed and high stress operations.

Description

Preliminary coating composition for metal substrates and a method of providing the same to a metal substrate

The present invention relates to the lubrication of pre-coated metals, such as TIN FREE STEEL, used in multiple forming operations where the final product has a continuous coating in the representation. This lubrication is necessary to protect the precoating material from damage that may be worn or scratched during molding. Typically, lubrication is applied locally on the precoat.

This lubrication is applied by rollers, sprayers, brushes, electrostatic dispersion or spot applications after precoating operations or just prior to press operations in which the product is molded in multiple operations on precoated and lubricated metals. The most economical way to lubricate the precoat is by hot sprayer at a rate of 600-800 ft / min (18,288 cm-24,384 cm) per minute simultaneously on both sides of the precoat coil metal. In particular, the coil coater cools the precoat sheet in a curing furnace in which the precoat is cured, and then takes it out and adds a thin film of lubricant with a hot sprayer. Since this is done at high speed, the bloom of internal lubricant does not appear on the precoated surface.

The low speed method used for sheet coating as opposed to coils handles sheet lengths of 110-3 ft (3353-91 cm) per minute on only one side. Thus, the speed of such a device is about one quarter of the speed of the coil coater which covers both sides almost simultaneously. Unlike coil coaters, here it is cured for 10 minutes to incubate the internal lubricant. Each sheet is secured by the wicking of the Wicketing Rack as it passes through the curing furnace. This device allows for relatively uniform blooming to see consistently low levels of lubricant (up to about 1.5% by weight) during sheet coating operations. In addition, locally applied lubricants are applied more accurately in low-speed sheet coating. Coil sheaths, on the other hand, have speed but little or no accuracy in terms of local coverage or uniformity. A good amount of lubricant is 12 mg / ft ² (0.0129 mg / cm 2) per side for both coil and sheet coaters. Both tolerances are more difficult to achieve in coil coaters than in ± 7 mg (± 0.0097 mg) or sheet coaters.

Choosing the right lubricant is also important. Lubricants should not affect the adhesion of the precoat to the metal surface and should be compatible with the intended use of the product formed by multiple molding operations. Lubricants are incompatible with the precoat, but should not affect the adhesion of the precoat in multiple molding operations and in subsequent use of the molded article. This incompatibility acts to create a lubricant float on the surface of the coating upon curing, which is called blooming. Any state is possible. Therefore, it is important to choose a lubricant that has the necessary incompatibility, but is not separated before application, and mixed with the precoat to provide the necessary lubrication properties to overcome the excessive pressures in metal forming operations, thereby protecting the precoat and metal from such stresses. .

It has been done by adding a small amount of lubricant to the precoat to work continuously in a locally overlubricated state. In particular, it has been found that by adding up to 2% by weight of lubricant to the precoat, it provides sufficient lubrication when local hyperspray is applied evenly in this ratio.

Examples of molded articles made in a multi-molding operation are described in United States Application No. 234,428, February 13, 1981 (container tool), February 13, 1981, Application No. 234,452 (container), and February 13, 1981 US application 234,451 (container manufacturing method) and the like. In these applications, the metals are subjected to ironing with a more accurate criticality of lubrication. Most coating lubricant mixtures tend to break down due to stresses and loads during such processing. Therefore, it is important to have special lubrication properties that can withstand the heat and pressure generated during ironing operations without the need for any additional coolant or lubricant.

Accordingly, it is an object of the present invention to provide a method by which an appropriate lubricant can be used against the stresses generated during multiple molding operations.

It is a further object of the present invention to provide a means for properly applying lubricant in a proportion sufficient to provide the necessary lubrication that enables multiple molding of the precoat material without damaging the coating of the material.

Another object of the present invention is to provide a special and good lubricant which acts to facilitate high speed multiplexing of food cans.

In order to meet these objectives and overcome the problems of the prior art of lubricating pre-coated metals, special lubricants are described which act according to the stress values occurring in the multiple molding operation. In particular, since heat is generated when molding at high pressures, the lubricant must be able to work under both conditions of heat and pressure to protect the pre-coated and pre-coated metals from fracture. It has been found that anhydrous coating lubricants can be used as solid solid protective layers at temperatures generated during molding operations because they are dispersed in solvents and contained in coatings. It is essential that the melting point of the solid lubricant is adjusted according to the amount of heat present in the multiple molding step, so that the lubricant is available in flowable form when the temperature exceeds a predetermined level. In a preferred embodiment, the temperature was found to be around 138 ° C. (280 ° F.). In order to solve problems such as abrasion and tearing of the drawn and ironed containers by the methods mentioned in these prior applications, the container contains a lubricant having a high melting point applied on the surface that later becomes external. Precoated with an epoxy phenol or epoxy urea formaldehyde formulation. Waxes or dispersants having these high melting point temperatures in n-butanol may be polyethylene or carnauba. This technique can be applied to any of the Fisher-Tropsch types, which may be possible as a slip agent, as long as the melting point can be adjusted to work in special multiple molding conditions by containing a sufficient amount of wax in the precoat. It can also be used in combination with a hydrocarbon polymer. In addition, the need for additional local lubrication can be reduced or eliminated, and the ability to produce a finished product from pre-coated metal can be maintained in high speed and high stress operations such as a combination of drawing and ironing. .

The present invention is directed to pre-coating for later use of thin gauges and various types of metal sheets that are molded into containers smaller than height. Since such containers are usually used for canning processed foods, they must be able to withstand the internal pressures generated during processing at high temperatures and the external pressures due to vacuum generated during cooling. A problem with the preliminary coating is the coating on the surface which later becomes the outside or inside of the container. The sheathing should be able to withstand the severe draw and redraw operations, including the underside forming, which is carried out when the flat, thin gauged precoated plate is highway changed into a hollow cylindrical vessel. Usually the coating is locally lubricated to facilitate fabrication. We have found that by realizing internal lubrication, cans can be manufactured without local lubrication.

인치(10.80cm)와 높이

인치(8.73cm)인 용기를 404×307이라 부른다.The can size in the present invention is indicated using the terminology of conventional can makers (conventional can makers add 1/16 inch (1.16 cm) in diameter across the completed double seal and add 1/16 in height. Add an inch (0.16 cm)). Thus, the diameter

Inches (10.80 cm) and height

An inch (8.73 cm) container is called 404 × 307.

65 # per base box material used in connection with the container molding of the present invention is a base box term meaning base weight. Originally, such terminology refers to the amount of steel in the base box of a tin plate of 112 ″ 14 ″ × 20 ″ (35.56 cm × 50.80 cm) or 31,360 in ² (202,322 cm ² ). At present, the base box is concerned with the basis weight relating to the amount of steel in the steel sheet of 31,360 in ² , whether in coil form or cut plate form. Typically, tin-free steel in the form of chromium is represented by TFS-CT, and electrolytically plated tin on the steel is represented by ETP. The amount of tin is also expressed in pounds per base box.

The coating can be tested experimentally by tape test before or after disinfection of the food, wherein each sample vessel multiformed from the precoat is applied to the surface on the cured, drawing and multiple reloaded precoats. It may be tested with a pressure sensitive adhesive tape such as 3M Tape # 610 in strip form 1 inch (2.54 cm) applied. The tape is pressed against the surface with sufficient force to allow full contact (ie no bubbles in between). The tape test is an effort to strip the cloth. It is necessary to quickly peel off the tape from the tape attachment coating surface by lifting some weakly bonded coating. To test the sheath adhesion, draw X marks with a sharp, pointed instrument on the sheath before the tape is attached. These X marks represent the newly created cut edges that are the starting point for any flaking that may occur later.

온스(751g)와 1갤론(3785㎤)의 증류수로 희석된 농축 염화수소산 용액

온스(184g)를 혼합함으로써 만들어진다. 용액에 침지한 후, 캔을 물에 행군 다음 구리 침전물을 육안으로 조사하였다. 표면상의 어떤 구리의 흔적은 피복 연속성의 결핍을 나타내며, 특히, 형상과 위치에 따라 불연속성의 정확한 특성을 보여준다.Once the container is made from the precoat by multiple molding operations, it is important to investigate whether the container is adequately protected by the precoat. A quick test to determine whether the outer cladding is broken during multiple molding operations involves the use of copper sulfate. Each vessel is immersed in a copper sulfate solution for 2 minutes. Solution is copper sulfate crystal

Concentrated hydrochloric acid solution diluted with 1 oz (751 g) and 1 gallon (3785 cm3) of distilled water

Made by mixing ounces (184 g). After immersion in the solution, the cans were rinsed in water and the copper precipitates were visually inspected. Traces of any copper on the surface indicate a lack of coating continuity, in particular the exact nature of the discontinuity depending on shape and location.

Another more representative test of the anticipated use of such containers is the so-called water pack test. Multiple forming vessels are filled with distilled water to the top. When the vessel is closed and a vacuum of 13 inches (330 mm) of mercury is applied, a quarter inch (6.35 mm) of upper space remains. These cans are then placed in a distiller and then steamed at 130 ° C. (265 ° F.) for 90 minutes. Following the distiller treatment, the cans are press cooled for 7 minutes. This procedure allows the container to receive conditions similar to those occurring during use of the container as a food pack. The distilled vessel is then inspected, patented, the outer coating is inspected after the vessel is air dried overnight. In addition, these containers may be stored in a high humidity chamber to facilitate oxidation of any exposed outer metal surface, if desired. Such oxidation indicates the degree of resistance that the precoat vessel must be treated with. Likewise, a copper sulfate test may be used. That is, after the treatment test, the coating discontinuity zone may be immersed in copper sulfate for special isolation.

Example 1

20% dispersion of the high melting point polyethylene [softening point 138 ° C (280 ° F)] to n-butanol SL280 from Daniel Products is epoxy-based from SCM Glidden Coatings and Resins. Urea-formaldehyde formulation (epoxy-urea-formaldehyde formulation) was added to GL650C136. The level of anhydrous lubricant used was in the range of 1/2 to 6% of the total nonvolatile resin solids in the coating, resulting in two functions.

(a) By adding only 1/2 to 2% of polyethylene as an internal lubricant to the coating, ironing and multiple drawing of 65 pound (29.5 kg) TFS plates precoated with the present composition can be achieved at speeds up to 125spm. Could.

(b) The addition of 2,4 and 6% polyethylene as a complete lubricant enables triple drawing and ironing operations (add any oil locally to form an unweared, commercially available can. The adhesion and fixation of the coating with the polyethylene lubricant was excellent even after 90 minutes of distillation at 130 ° C. (265 ° F.).

Example 2

A 24% dispersion of polyethylene SL177 (softening point 138 ° C. (280 ° F.)) in xylene from Daniel Products was added to an epoxy phenolic coating (trade name: MC9372-006) from Mobil Chemical.

The level of lubricant used was 2% and 4% by weight of the total resin solids in the coating. When cured for 9 minutes at 205 ° C. (400 ° F.) in an amount of 9 mg / 4 in ² (0.35 mg / cm 2), the coating was capable of triple drawing with ironing of 65 pounds (29.5 kg) TFS. .

Example 3

The same dispersion of polyethylene SL177 as in the previous example was used with a 20% dispersion of Daniel Product's Polymer Wax SL425 (softening point 107 ° C. (225 ° F.)) mixed with Mobil Chemical's epoxy phenol MC9372-006 in a 4: 1 ratio. The addition of low levels of polymer wax improved the wear resistant drawing and ironing properties of epoxy phenols at both 65 pound (29.5 kg) TFS and 65 pound (29.5 kg) No. 25 ETFs.

Example 4

A 20% dispersion of polyethylene SL50 (softening point 107 ° C. (225 ° F.)) to n-butanol from Daniel Products was mixed in three white colored inner enamels. The first was Ghürden's phenol-modified epoxy-urea formulation GL588-92C. Others were WS28-419 and WS28-420 from Watson Standard, both vinyl organosols. In 2% anhydrous polyethylene, these precoats provided a good product without any loss of adhesion. The SL50 is approved by the FDA for coatings in contact with food.

The following examples not only have low melting point Carnauba wax but also do not run in a continuous operation, demonstrating the importance of lubrication conditions at the point of forming stress and heat.

[Example 5 and Example 6]

The outer coating of the draw and ironed cans of two coatings containing 1.95% of carnauba wax dispersed in solid proportions in Mobil Chemical's epoxy phenolic MC9372-007 and epoxy-urea-formaldehyde MC8406-020. Checked as. The cans were made on guide lines by first cupping with one press and then multiple forming or redrawing with another press. The pre-coating containing carnauba wax failed when transferred to a press having a continuous molding sequence due to high temperatures. The delay time between the cupping station and the forming station of the two press apparatuses described above allowed for the dissipation of heat between the steps. Carnauba wax was ineffective in presses with a continuous sequence where higher instantaneous temperatures occurred. As a result, lubricants with higher softening points as in Examples 1-4 are needed in continuous high temperature multiple molding sequences.

EXAMPLE 7 AND 8

Prepared as an outer precoat for high speed multi-moulding by drawing a dispersion containing 1% and 2% carnauba wax in solid proportions in the epoxy-urea-formaldehyde GL588-44 from Griden Coatings Tested. The 1% Example left a trace of surface roughness after the water test. The 2% Example allowed for good cans to be made and passed both a water packaging test and a copper sulfate test. This wax is sufficient for triple drawing with ironing on two press apparatuses, and the results on the press with a continuous molding sequence are consistent with the results found in Examples 5 and 6.

The softening point is the temperature or temperature range at which the material softens. Perkin-Elmer TMS-1 thermomechanical analyzer is used to determine this property.

The cladding specimen is punched from the sheet and placed under the load probe. Then, the temperature in the predetermined programmed range is scanned. When the sheath begins to swallow, the probe begins to penetrate the sheath, and an apparent interruption occurs on the recorder chart. The softening point is the temperature corresponding to the midpoint of the line tangentially drawn to the breakpoint of the curve between the pre-transition baseline and the post-transition baseline. The softening point is a factor influencing the drawing and ironing properties of the coating. If the internal lubricant is soft or liquid, the softening point of the coating drops considerably. Thus, 0.5% lanolin in the griden formulation shows a softening point of 84 ° C. (183 ° F.) for the cured coating, while a polyethylene having a melting point of 138 ° C. (280 ° F.) when incorporated into the same griden formulation. Solid solid waxes such as have a softening point of 90 ° C. (194 ° F.). The first embodiment failed satisfactory drawing and ironing, but the second passed this manufacturing test. The following table summarizes the above embodiments.

* No local lubricant is applied to this specimen.

** The largest change in Example 1

Other examples given in the table here show that the softening point is inversely proportional to the concentration of the internal lubricant, wax or anhydrous coating. These embodiments work despite the low softening point due to the partial movement of the lubricant to the cladding surface.

High melting point waxes form a hard protective layer over the coating, while low melting waxes and liquid lubricants liquefy and wash away, leaving a relatively unprotected coating susceptible to manufacturing stress.

Although specific additions of various anhydrous coating lubricants such as polymer waxes and carnauba wax have been described and described, the present invention expands its scope by adding anhydrous coatings added to the coating in an amount sufficient to effectively increase the softening point of the coating. Relates to the use of lubricants. In other words, the anhydrous coating lubricant should have a softening point equal to or higher than that of the coating so that it can be used in connection with protecting the coating during multiple molding operations. Accordingly, the following claims cover applications relating to certain anhydrous coating materials and metal substrates thereof added to the precoat.

Claims (14)

A method of providing a metal substrate with increased lubricity and wear resistance when the coated metal is subjected to multiple molding operations, the method comprising: vinyl, epoxy-phenol or epoxy that retains adhesion to the metal substrate when molded by stretching and molding operations Anhydrous of about 0.5 to 6%, providing a urea-formaldehyde coating material and having a melting point higher than the melting point of the coating material, selected from the group consisting of polyethylene wax and carnauba wax, before being applied to the substrate Mixing the coating lubricant and applying the coating material and lubricant mixture to the metal substrate with a thin coating layer such that the later cured coating that is cured to adhere to the metal substrate has a softening point of at least 85 ° C. (185 ° F.). Providing a metal substrate with increased lubricity and wear resistance. A method of increasing the lubricity and abrasion resistance of a cured metal coating composition, comprising: vinyl, epoxy-phenol and epoxy-urea-formaldehyde resins, wherein the coating retains adhesion to the metal substrate after curing and can withstand stretching and forming operations In a metal coating composition having a resin selected from the group consisting of: a polyethylene wax and a carnauba wax each having a melting point of at least 85 ° C. (185 ° F.) and having a melting point that is essentially higher than the melting point of the coating composition. A method of increasing the lubricity and wear resistance of a cured metal coating composition characterized by adding about 0.5 to 1 weight percent of anhydrous lubricant. A precoat composition for a metal substrate that is cured to form an adhesive coating on the metal substrate, wherein vinyl, epoxy-phenol and epoxy, which are well adhered to the metal surface after curing and can be molded together with the metal by stretching and drawing operations A coating material having a resin selected from the group consisting of urea-formaldehyde resins and essentially selected from the group consisting of polyethylene wax and carnauba wax each having a melting point of at least 85 ° C. (185 ° F.). A precoat composition for metal substrates having a melting point higher than the melting point of and comprising about 0.5 to 6% by weight of anhydrous coating lubricant uniformly mixed with the coating material. The method of claim 1, wherein the anhydrous film lubricant is polyethylene wax. 5. The method of claim 4, wherein 1% by weight of polyethylene wax is added to the coating material. 6. The method of claim 5, wherein 0.5% by weight of polyethylene wax is added to the coating material. The method of claim 6, wherein the anhydrous coating lubricant has a melting point in excess of 210 ° F. (99 ° C.). 2. The method of claim 1, wherein the coating material is an epoxy-phenolic resin material and the anhydrous coating lubricant is polyethylene wax. A method of making a molded article from a metal substrate having a cured coating thereon, comprising: a vinyl, epoxy-phenol or epoxy-urea-formaldehyde coating material that retains adhesion to the metal substrate when molded by stretching and molding operations A group consisting of polyethylene wax and carnauba wax, each having a melting point of at least 85 ° C. (185 ° F.) in the coating material prior to application to the substrate to provide and increase the lubricity and wear resistance of the coating material during the stretching and molding operations. From about 0.5 to 1% by weight of anhydrous lubricant coated with a melting point selected essentially from the melting point of the coating composition, and adding the coating material and the lubricant mixture to the metal substrate as a thin coating layer, at a temperature of about 85 ° C. (185 ° F.) The mixture was lowered to form an adhesive coating having a softening point on the metal substrate, and then Method for producing a molded article from the lubricant material on the coated metal substrate having on the cured coating, characterized in that comprises the steps of performing a forming operation on the coated substrate to soften the molding working. 10. The method of claim 9, wherein the molding operation is a multiple drawing or multiple drawing and ironing can manufacturing operation. The precoating composition for a metal substrate according to claim 3, wherein the anhydrous coating lubricant is polyethylene wax. 12. The precoat composition for a metal substrate according to claim 11, wherein 1% by weight of polyethylene wax is added to the coating material. The precoat composition of claim 11, wherein the anhydrous coating lubricant has a melting point in excess of 99 ° C. (210 ° F.). The precoat composition for a metal substrate of claim 13, wherein the coating material is an epoxy-phenolic resin material and the anhydrous coating lubricant is polyethylene wax.