CA1178041A - Method of preventing formation of rust on end of metal containers - Google Patents
Method of preventing formation of rust on end of metal containersInfo
- Publication number
- CA1178041A CA1178041A CA000404249A CA404249A CA1178041A CA 1178041 A CA1178041 A CA 1178041A CA 000404249 A CA000404249 A CA 000404249A CA 404249 A CA404249 A CA 404249A CA 1178041 A CA1178041 A CA 1178041A
- Authority
- CA
- Canada
- Prior art keywords
- composition
- phosphate salt
- lining composition
- rust
- phosphate
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Landscapes
- Paints Or Removers (AREA)
- Chemical Treatment Of Metals (AREA)
- Preventing Corrosion Or Incrustation Of Metals (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A method for preventing formation of rust on the ends of metal con-tainers is described which comprises treating a container sealing composition with a phosphate salt prior to applying the sealing composition to the end of the container. The container sealing composition produced by this method will result in a seal which inhibits the formation of rust on the ends of metal containers under various drying conditions, i.e. oven drying or air drying, regardless of the relative humidity.
A method for preventing formation of rust on the ends of metal con-tainers is described which comprises treating a container sealing composition with a phosphate salt prior to applying the sealing composition to the end of the container. The container sealing composition produced by this method will result in a seal which inhibits the formation of rust on the ends of metal containers under various drying conditions, i.e. oven drying or air drying, regardless of the relative humidity.
Description
1 1~8~41 BACKGRQlN~ O~ THE INVENTION
This invention relates to the field of container end sealing compounds, and, in particular, to a method of modif~ing a container end sealing compound so that formation of rust at the exposed edges of metal container ends is preventedO
The art of container sealing has an established terminology which will be used in this specificationO The walls of the container are known as the "bodyl'. The end closures are known as "ends". The gasket which is interposed bet~een the ends and bod~ and is responsible for the hermetic or liquid-tight seal betw-een the parts is known as the "lining". The plastic or liquid composition ~hich, upon cooling or drying forms the solid gasket, is known as ''lining''O
The bod~ of the can is a crlindrical piece of sheet metal normally made by forming a rectangular piece of metal and then joining the ends of the rectang~le along the side seam. The metal in the ends of the cylinder are flanged outwardly. The can is completed by placing a circular piece of metal called the "end" over each end of the cylinder and rolling the outer edge of the end and flange on the body together in a double seam. The can ends are made in a separate operation b~ stamping a blank from like material which ma~ be tin plate, black plate, aluminum, or other sheet metal. That portion of the end ~hich covers the interior of the can is called the "panel". The outer periphery of the end is formed into a circular depression called the "channel" ~hich cooperates with the flange on either end of the body. The outer edge of the channel called the "curl" is deformed upwardly and inwardl~ to provide contact of the can end ~ith the inner side of the flange of the can bod~ during the first stage of the double seaming operation. The "cut edge"
'~
\
~ 178041 of a metal can end reers to the exposed edge of the can end located at the curl area of the can end. The exposed edge comes into being when the can end is formed by means of the stamping operation. The cut edge is prone to corrosion because of the lack of protective coating or lacquer over the cut edge. The remaining portion of the panel is generally resistant to corrosion because it is covered with a protective coating that has not been damaged or removed by the stamping operationO The inner wall of the channel, i.e., the portion between the channel and the panel, is known as the "shoulder". The plastic or liquid composition which forms the "lining" is placed in the channel of the can endO
Sealing compounds for can covers ~"ends") are commonly applied to the covers in liquid formO The machines, called "lining machines" which apply the compound to the joint area, have, as essential operating elements, a con-tinuously rotating chuck which receives and rotates the cover, a "nozzle", essentiallr a squirt gun, controlled by a needle valve which projects the compound downwardly onto the joint area of the cover, and a quick opening and closing cam which lifts the needle valve and closes it at the proper instant.
common type of compound-applying machine removes a blank closure from a stack; slides the closure along a table; places it on a continuously revolving chuck, where the compound is applied and placed; pushes the closure from the chuck; tucks it beneath a stack of finished closures, and places a new closure on the chuck in a single cycle of operation. After the can ends have been lined, they are conveyed to an area where the volatile components of the sealing composition are removed.
Through the operation of the lining machine, a ring of fluid
This invention relates to the field of container end sealing compounds, and, in particular, to a method of modif~ing a container end sealing compound so that formation of rust at the exposed edges of metal container ends is preventedO
The art of container sealing has an established terminology which will be used in this specificationO The walls of the container are known as the "bodyl'. The end closures are known as "ends". The gasket which is interposed bet~een the ends and bod~ and is responsible for the hermetic or liquid-tight seal betw-een the parts is known as the "lining". The plastic or liquid composition ~hich, upon cooling or drying forms the solid gasket, is known as ''lining''O
The bod~ of the can is a crlindrical piece of sheet metal normally made by forming a rectangular piece of metal and then joining the ends of the rectang~le along the side seam. The metal in the ends of the cylinder are flanged outwardly. The can is completed by placing a circular piece of metal called the "end" over each end of the cylinder and rolling the outer edge of the end and flange on the body together in a double seam. The can ends are made in a separate operation b~ stamping a blank from like material which ma~ be tin plate, black plate, aluminum, or other sheet metal. That portion of the end ~hich covers the interior of the can is called the "panel". The outer periphery of the end is formed into a circular depression called the "channel" ~hich cooperates with the flange on either end of the body. The outer edge of the channel called the "curl" is deformed upwardly and inwardl~ to provide contact of the can end ~ith the inner side of the flange of the can bod~ during the first stage of the double seaming operation. The "cut edge"
'~
\
~ 178041 of a metal can end reers to the exposed edge of the can end located at the curl area of the can end. The exposed edge comes into being when the can end is formed by means of the stamping operation. The cut edge is prone to corrosion because of the lack of protective coating or lacquer over the cut edge. The remaining portion of the panel is generally resistant to corrosion because it is covered with a protective coating that has not been damaged or removed by the stamping operationO The inner wall of the channel, i.e., the portion between the channel and the panel, is known as the "shoulder". The plastic or liquid composition which forms the "lining" is placed in the channel of the can endO
Sealing compounds for can covers ~"ends") are commonly applied to the covers in liquid formO The machines, called "lining machines" which apply the compound to the joint area, have, as essential operating elements, a con-tinuously rotating chuck which receives and rotates the cover, a "nozzle", essentiallr a squirt gun, controlled by a needle valve which projects the compound downwardly onto the joint area of the cover, and a quick opening and closing cam which lifts the needle valve and closes it at the proper instant.
common type of compound-applying machine removes a blank closure from a stack; slides the closure along a table; places it on a continuously revolving chuck, where the compound is applied and placed; pushes the closure from the chuck; tucks it beneath a stack of finished closures, and places a new closure on the chuck in a single cycle of operation. After the can ends have been lined, they are conveyed to an area where the volatile components of the sealing composition are removed.
Through the operation of the lining machine, a ring of fluid
-2 ~ ~78041 compound is formed on the joint area adjacent the periphery of the can end.
This ring of compound, whether in liquid form or later when it is dried, or fluxed into a solid mass is called the "lining". Its function is to form the gasket between the can parts and hermetically seal the can.
Ballou et al, United States Patent 3,013,896 and Flaherty, United States Patent 3,310,196 describe the basic operations employed in lining can ends and attaching the can ends to the can body.
Water-based can end lining compositions are water dispersions of special rubbers which, when flowed into can ends and dried, provide a hermetic seal. The solids portion of a water-based can end lining composition ranges from about 30 percent to about 85 percent of the total composition.
~: Based upon 100 parts per hundred of rubber (hereinafter referred to as phr), the solids portion of a typical water-based lining composition has the following composition (all parts are expressed in weight):
Ingredient ~mount Rubber 100 phr Pigment and/or filler 50-200 phr Resin 0~100 phr Antioxidant less than 1%
Bacteriocide less than 1%
Surface Active Agents 0.5% to 10%
` The remaining 15 percent to 70 percent of the total composition consists of water. The conventional method of drying the water-based compositions involves the use of an oven drier. Air drying with no mechanical assist can also be ,",~
, :, .
, ~ -3-.
1 ~78041 utilized.
A seriQus~problem with ~ater~based can end lining compositions is that the~ tend to promote rust and/or corrosion in the area of the cut edge of a metal can end. This rust or corrosion is caused primaril~ by high humidity conditions which are induced by the environment of the can end lining operation~
~hen a stack of can ends lined ~ith a water-based can end lining composition is placed in the interior of a pallet containing stacks of lined can ends, the water present in the lining composition promote~ corrosion in the area of the cut edge of the can end, because the absence of circulation of air retards the evapo~ation of water from the lining compositionO The components of the water_based can sealing composition ~ill also induce rust or corrosion through various chemical means.
Solvent-based can end lining compositions are primarily solvent solutions of special rubberO Solvent-based can end compositions may also pro-mote rust near the cut edge of a metal can endJ but to a lesser extent than water-based can end lining compositions.
Numerous materials have been employed effectively as rust inhibitors for metal can ends. These materials include sodium hydroxide ~pH 11), potassium hydroxide ~pH 11), triethanolamine, diethanolamine, monoethanolamine, sodium benzoate, and sodium. Each of these materials is effective to some degree. The effectiveness of these materials is based on their ability to inactivate either the surface of the subytrate or the components of the lining compositions.
Although these materials retard the rusting of steel can ends, it ~ would be desirable to essentially eliminate the formation of rust at the ; exposed edges of the can ends.
1 17~04 1 This invention seeks to provide a method for preventing formation of rust on metal can ends.
Also, this invention seeks to provide a method for preventing forma-tion of rust at the cut edge of any type of metal product susceptible to corrosion by rust.
We have discovered a method of modifying container end sealing compound so that formation of rust on steel container ends is virtually elim-inated. The method involves adding a phosphate compound to a container sealing compound formulation prior to applying the container sealing compound to the container end. Hollingshad, United States Patent 3,941,562 discloses a method of inhibiting the corrosion of metals in a water system by maintaining in the water of the system at least about 10 ppm of a composition comprising a polyacrylamide and a source of orthophosphate. This method, however, is unsuitable for prevention of rust on the cut edge of metal can end, because product specifications will not always allow manufacturers to incorporate the polyacrylamide/orthophosphate composition into the product which is to be stored in the can.
` The terms "can end lining composition" and "can end lining compound", ; and "lining composition" and "lining compound", are used interchangeably in the specification and claims of this disclosure.
SUMMARY OF THE INVENTION
, .
This invention involves a method for preventing the formation of rust and/or corrosion at the panel and the cut edge of a metal container end.
The method comprises treating a container sealing compound with :
., ~ 178041 a phosphate salt prior to applying sealing compound to the end o~ the container.
The seal thus formed rom the treated sealing compound is effective in preventing rust formation at the outer edge of the container end.
DETAILED DESCRIPTION
The addition of a suitable phosphate salt to a can end lining compound formulation will allow-the formulation to inhibit the formation of rust and/or corrosion at the cut edge of a metal can end.
The can end lining compound formulations contemplated for use in this invention include both water-based formulations and solvent based formulations. A suitable water-based formulation is described below. This formulation contains about 15 weight percent to about 60 ~eight percent water, and about 40 weight percent to about 85 weight percent solids. The foregoing percentages are based on total weight of the formulation. The solids component is further characterized as comprising the following ingredients in the amounts indicated:
IngredientAmount ~percent, based on total weight of solids component only) . Binder 24 - 65 Resins 0 - 24 Emulsifiers0 - 3 Filler 20 ~ 60 Antioxidant0 - 1 The preferred binder is rubber (SBR)o The preferred resins are resins derived from hydrocarbons. Suitable fillers include silicates, such as talc, clays, and sodium silicate. In addition to the foregoing ingredients, a water-based can end lining compound may also contain thickeners, pH modifiers, processing .
~ 178~41 aids, plas*icizers-, oils, anti-microbialogical protectorants, e.g. mildewcides, biocides, fungicides, and coalescense aids.
A suitable solvent-based formulation contains non-volatile components which are similar to those of conventional water~based formulations~ The composition of the particular can end lining composi~ion is not critical to this invention.
Phosphate salts which are suitable for this invention include mono-alkali, di-alkali, and tri-alkali metal phosphate salts. These alkali metal phosphate salts may be anhydrous or hydrated. Examples of these salts are monosodium phosphate, monopotassium phosphate, and trisodium phosphate~ It should be understood that the suitable alkali metal phosphate salts are not limited to the foregoing examplesD
In order to utilize the phosphate salt as a rust preventative, it may first have to be treated with a suitable base to raise the pH of the salt to the pH level of the can end lining compound. The addition of the base is unnecessar~ if the pH of the phos.phate salt is reasonabl~ close to or com-patible with the pH of the can end lining composition.
To a water-based can end lining composition should be added about 0.1 weight percent to about 3 weigh~ percent phosphate salt, based on the weight of the lining composition. A higher concentration of phosphate salt may be emplo~ed; however, no appreciable improvement in rust inhibition is noted at phosphate concentrations above about 3 weight percent phosphate salt. The preferred concentration of salt in the lining composition is about 0.7 weight percent.
It may be desirable to add alkali to the phosphate treated container sealing composition The purpose of the alkali addition is to prevent fl~ccul-1 ~78~41 ation during formulation of the composition.
The following specific examples are illustrative but not limitativeof the invention; it should be understood that similar results are obtainable ~ith other combinations of differen~ ingredients. All such variations which do not depart from the basic concept of this invention and composition disclosed herein are intended to come within the scope of the appended claims.
T~o parts by ~eight of ammonia ~NH3) ~as added to 100 parts by ~eight of a 33 percent aqueous solution of monosodium phosphate. The pH of the mono-sodium phosphate solution reached 7.
The pH-adjusted monosodium phosphate ~as added to a ~ater-based can :.
end lining composition at concentration varying from 0.5 parts of phosphate per - hundred parts of rubber to 4 parts of phosphate per hundred parts of rubber.
The lining composition contained the following components in the amounts indicated ~all parts are expressed in ~eight~:
Solids Portion ~73 percent of total composition) 100 parts rubber 200 parts pigment and/or filler 1 part antioxidant 1 part bacteriocide 0.5_4 parts rust inhibitor 10 parts surfactants, thickeners Liquid Portion ~27 percent of total composition) 100 parts ~ater The .specific gravity of the lining composition ~as 1.62.
~` Tests were conducted on a variety of substrates, e.g., can ends, ".
':
'., ~ ~78041 flat plate. Test conditions specified exposure of the substrate to 97 percent relative humidity for a minimum of 72 hours. To evaluate tin plate~ whether in sheet or in can end form, the substrate was scored to expose the steel underbody. This action resulted in a much more demanding test with increased sensitivity.
The following Table shows the results of tests which demonstrate the effectiveness of the method of this invention in preventing corrosion of the end of metal containers and of metal plate in general.
'~
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~ ~ ~~ ~ ~ O ~ o O O o O
E~ :~ t/~ Cd Z P:~ Z Z Z Z Z
4~
O ho O ~rl ,D h OLr) O O o o u~ o o o h ~:: o ~ d 0 0~
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'~ tn h hS~X X ~ n ~d a ~ t ~0 ~ ~ Z Z Z 3 tn ~>
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o O E~ ~ u~~n tn~ ~n tn c~ a h 3 ~ ~ 3 .: ~ t h o o Z Z
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. ~ ~ ~- ~ tn \O ~D ~ ~ ,~
O h -- h .a ~ h . ~ ,~ o n o o o 'u ~d h 3 ~ V
o O h ' ~S ~ ~
f ~ ~ t 0 ~4 ~ ~ t~ h tn ~ n ~ ~ ~3 V
., ~ ~ .~ n h ~ ~0 ~3 cn ~ ~ V ~D 1 ~ m . ~ X ~: - v bl~ V 'V ~ h O
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,~' V V O
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q~ ~ h ~ h O ~ ,a a ~ ~
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~ .,, :: a ~ ~ ~12-' 11~8041 ; The foregoing Table shows that increaslng the concentration of phos-phate in the can end llning compound decreases the level of rust formation on the lined can end, tinplate, and blackplate. As little as 1 part phosphate per hundred parts rubber ~ill prevent the formation of rust on a scored can end ~hich is subjected to 97 percent relative humidit~ for at least 72 hours.
As little as 4 parts phosphate per hundred parts rubber will prevent the formation of rust on scored flat plate which is subjected to 97 percen~
relative humidity for at least 72 hours. Higher concentrations of phosphate salt may be employed; however, no appreciable improvement in rust inhibition is noted at phosphate salt concentrations above 4 parts phosphate per hundred parts rubber, . .
-13~
, .
,.,
This ring of compound, whether in liquid form or later when it is dried, or fluxed into a solid mass is called the "lining". Its function is to form the gasket between the can parts and hermetically seal the can.
Ballou et al, United States Patent 3,013,896 and Flaherty, United States Patent 3,310,196 describe the basic operations employed in lining can ends and attaching the can ends to the can body.
Water-based can end lining compositions are water dispersions of special rubbers which, when flowed into can ends and dried, provide a hermetic seal. The solids portion of a water-based can end lining composition ranges from about 30 percent to about 85 percent of the total composition.
~: Based upon 100 parts per hundred of rubber (hereinafter referred to as phr), the solids portion of a typical water-based lining composition has the following composition (all parts are expressed in weight):
Ingredient ~mount Rubber 100 phr Pigment and/or filler 50-200 phr Resin 0~100 phr Antioxidant less than 1%
Bacteriocide less than 1%
Surface Active Agents 0.5% to 10%
` The remaining 15 percent to 70 percent of the total composition consists of water. The conventional method of drying the water-based compositions involves the use of an oven drier. Air drying with no mechanical assist can also be ,",~
, :, .
, ~ -3-.
1 ~78041 utilized.
A seriQus~problem with ~ater~based can end lining compositions is that the~ tend to promote rust and/or corrosion in the area of the cut edge of a metal can end. This rust or corrosion is caused primaril~ by high humidity conditions which are induced by the environment of the can end lining operation~
~hen a stack of can ends lined ~ith a water-based can end lining composition is placed in the interior of a pallet containing stacks of lined can ends, the water present in the lining composition promote~ corrosion in the area of the cut edge of the can end, because the absence of circulation of air retards the evapo~ation of water from the lining compositionO The components of the water_based can sealing composition ~ill also induce rust or corrosion through various chemical means.
Solvent-based can end lining compositions are primarily solvent solutions of special rubberO Solvent-based can end compositions may also pro-mote rust near the cut edge of a metal can endJ but to a lesser extent than water-based can end lining compositions.
Numerous materials have been employed effectively as rust inhibitors for metal can ends. These materials include sodium hydroxide ~pH 11), potassium hydroxide ~pH 11), triethanolamine, diethanolamine, monoethanolamine, sodium benzoate, and sodium. Each of these materials is effective to some degree. The effectiveness of these materials is based on their ability to inactivate either the surface of the subytrate or the components of the lining compositions.
Although these materials retard the rusting of steel can ends, it ~ would be desirable to essentially eliminate the formation of rust at the ; exposed edges of the can ends.
1 17~04 1 This invention seeks to provide a method for preventing formation of rust on metal can ends.
Also, this invention seeks to provide a method for preventing forma-tion of rust at the cut edge of any type of metal product susceptible to corrosion by rust.
We have discovered a method of modifying container end sealing compound so that formation of rust on steel container ends is virtually elim-inated. The method involves adding a phosphate compound to a container sealing compound formulation prior to applying the container sealing compound to the container end. Hollingshad, United States Patent 3,941,562 discloses a method of inhibiting the corrosion of metals in a water system by maintaining in the water of the system at least about 10 ppm of a composition comprising a polyacrylamide and a source of orthophosphate. This method, however, is unsuitable for prevention of rust on the cut edge of metal can end, because product specifications will not always allow manufacturers to incorporate the polyacrylamide/orthophosphate composition into the product which is to be stored in the can.
` The terms "can end lining composition" and "can end lining compound", ; and "lining composition" and "lining compound", are used interchangeably in the specification and claims of this disclosure.
SUMMARY OF THE INVENTION
, .
This invention involves a method for preventing the formation of rust and/or corrosion at the panel and the cut edge of a metal container end.
The method comprises treating a container sealing compound with :
., ~ 178041 a phosphate salt prior to applying sealing compound to the end o~ the container.
The seal thus formed rom the treated sealing compound is effective in preventing rust formation at the outer edge of the container end.
DETAILED DESCRIPTION
The addition of a suitable phosphate salt to a can end lining compound formulation will allow-the formulation to inhibit the formation of rust and/or corrosion at the cut edge of a metal can end.
The can end lining compound formulations contemplated for use in this invention include both water-based formulations and solvent based formulations. A suitable water-based formulation is described below. This formulation contains about 15 weight percent to about 60 ~eight percent water, and about 40 weight percent to about 85 weight percent solids. The foregoing percentages are based on total weight of the formulation. The solids component is further characterized as comprising the following ingredients in the amounts indicated:
IngredientAmount ~percent, based on total weight of solids component only) . Binder 24 - 65 Resins 0 - 24 Emulsifiers0 - 3 Filler 20 ~ 60 Antioxidant0 - 1 The preferred binder is rubber (SBR)o The preferred resins are resins derived from hydrocarbons. Suitable fillers include silicates, such as talc, clays, and sodium silicate. In addition to the foregoing ingredients, a water-based can end lining compound may also contain thickeners, pH modifiers, processing .
~ 178~41 aids, plas*icizers-, oils, anti-microbialogical protectorants, e.g. mildewcides, biocides, fungicides, and coalescense aids.
A suitable solvent-based formulation contains non-volatile components which are similar to those of conventional water~based formulations~ The composition of the particular can end lining composi~ion is not critical to this invention.
Phosphate salts which are suitable for this invention include mono-alkali, di-alkali, and tri-alkali metal phosphate salts. These alkali metal phosphate salts may be anhydrous or hydrated. Examples of these salts are monosodium phosphate, monopotassium phosphate, and trisodium phosphate~ It should be understood that the suitable alkali metal phosphate salts are not limited to the foregoing examplesD
In order to utilize the phosphate salt as a rust preventative, it may first have to be treated with a suitable base to raise the pH of the salt to the pH level of the can end lining compound. The addition of the base is unnecessar~ if the pH of the phos.phate salt is reasonabl~ close to or com-patible with the pH of the can end lining composition.
To a water-based can end lining composition should be added about 0.1 weight percent to about 3 weigh~ percent phosphate salt, based on the weight of the lining composition. A higher concentration of phosphate salt may be emplo~ed; however, no appreciable improvement in rust inhibition is noted at phosphate concentrations above about 3 weight percent phosphate salt. The preferred concentration of salt in the lining composition is about 0.7 weight percent.
It may be desirable to add alkali to the phosphate treated container sealing composition The purpose of the alkali addition is to prevent fl~ccul-1 ~78~41 ation during formulation of the composition.
The following specific examples are illustrative but not limitativeof the invention; it should be understood that similar results are obtainable ~ith other combinations of differen~ ingredients. All such variations which do not depart from the basic concept of this invention and composition disclosed herein are intended to come within the scope of the appended claims.
T~o parts by ~eight of ammonia ~NH3) ~as added to 100 parts by ~eight of a 33 percent aqueous solution of monosodium phosphate. The pH of the mono-sodium phosphate solution reached 7.
The pH-adjusted monosodium phosphate ~as added to a ~ater-based can :.
end lining composition at concentration varying from 0.5 parts of phosphate per - hundred parts of rubber to 4 parts of phosphate per hundred parts of rubber.
The lining composition contained the following components in the amounts indicated ~all parts are expressed in ~eight~:
Solids Portion ~73 percent of total composition) 100 parts rubber 200 parts pigment and/or filler 1 part antioxidant 1 part bacteriocide 0.5_4 parts rust inhibitor 10 parts surfactants, thickeners Liquid Portion ~27 percent of total composition) 100 parts ~ater The .specific gravity of the lining composition ~as 1.62.
~` Tests were conducted on a variety of substrates, e.g., can ends, ".
':
'., ~ ~78041 flat plate. Test conditions specified exposure of the substrate to 97 percent relative humidity for a minimum of 72 hours. To evaluate tin plate~ whether in sheet or in can end form, the substrate was scored to expose the steel underbody. This action resulted in a much more demanding test with increased sensitivity.
The following Table shows the results of tests which demonstrate the effectiveness of the method of this invention in preventing corrosion of the end of metal containers and of metal plate in general.
'~
-` I 178~4 1 a , ~i , , . , , h V~
.,1 ~d ~d C~ ~
ho O
~ ~ ~ O
~ U~ V~
u~ h ~ ~ Z
'oH
~ c> a~
O c~: ~ ~ h h ~ ~ ~~d td O
H t~ E- h ~11 ~ ~.~ ,~
~ ~ ~~ ~ ~ O ~ o O O o O
E~ :~ t/~ Cd Z P:~ Z Z Z Z Z
4~
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., ~ ~ .~ n h ~ ~0 ~3 cn ~ ~ V ~D 1 ~ m . ~ X ~: - v bl~ V 'V ~ h O
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,~' V V O
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e ~ ~ ~
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~ .,, :: a ~ ~ ~12-' 11~8041 ; The foregoing Table shows that increaslng the concentration of phos-phate in the can end llning compound decreases the level of rust formation on the lined can end, tinplate, and blackplate. As little as 1 part phosphate per hundred parts rubber ~ill prevent the formation of rust on a scored can end ~hich is subjected to 97 percent relative humidit~ for at least 72 hours.
As little as 4 parts phosphate per hundred parts rubber will prevent the formation of rust on scored flat plate which is subjected to 97 percen~
relative humidity for at least 72 hours. Higher concentrations of phosphate salt may be employed; however, no appreciable improvement in rust inhibition is noted at phosphate salt concentrations above 4 parts phosphate per hundred parts rubber, . .
-13~
, .
,.,
Claims (12)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A method of inhibiting the formation of rust at the cut edge of a metal can end which comprises adding a phosphate salt to a can end lining composition, then applying said treated can end lining composition to said can end.
2. The method of Claim 1 wherein the phosphate salt is selected from the group consisting of anhydrous alkali metal phosphate salts and hydrated alkali metal phosphate salts.
3. The method of Claim 1 wherein a base is used to raise the pH of the phosphate salt to the pH level of the can end lining composition.
4. The method of Claim 1 wherein at least about 0.1 weight percent phosphate salt is added to the can end lining composition, based on the weight of the composition.
5. The method of Claim 1 wherein about 0.1 weight percent to about 3 weight percent phosphate salt is added to the can end lining composition, based on the weight of the composition.
6. The method of Claim 1 wherein the can end lining composition comprises a binder and a filler.
7. The method of Claim 6 wherein the binder is a rubber compound.
8. The method of Claim 7 wherein at least about 0.5 phr phosphate salt is added to the can end lining composition.
9. The method of Claim 7 wherein from about 0.5 phr to about 4 phr phosphate salt is added to the can end lining composition.
10. A method comprising the steps of providing a metal can end coated with a corrosion resistant coating and having a channel about its periphery and an exposed, uncoated cut edge which is prone to nesting; depositing into said channel a water based can end lining composition comprising a rubber bin-der, a filler, and at least 0.5 phr of a phosphate salt; and drying said lining composition in an oven, thereby providing a lined can end without rusting at said cut edge.
11. A method according to claim 10 wherein the water based can end lin-ing composition contains at least 15% by weight water.
12. A method according to claim 10 including the additional step of adding a base to the phosphate salt to raise the pH of the phosphate salt to the pH level of the water based can end lining composition.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US27067181A | 1981-06-04 | 1981-06-04 | |
| US270,671 | 1994-07-05 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1178041A true CA1178041A (en) | 1984-11-20 |
Family
ID=23032301
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000404249A Expired CA1178041A (en) | 1981-06-04 | 1982-06-01 | Method of preventing formation of rust on end of metal containers |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JPS582361A (en) |
| CA (1) | CA1178041A (en) |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5243835B2 (en) * | 1972-07-06 | 1977-11-02 | ||
| JPS52121636A (en) * | 1976-04-03 | 1977-10-13 | Dainippon Toryo Co Ltd | Corrosion-resistant primary paint compositions |
| JPS5396037A (en) * | 1977-02-01 | 1978-08-22 | Kansai Paint Co Ltd | Anticorrosive coating |
| JPS54113634A (en) * | 1978-02-27 | 1979-09-05 | Hitachi Ltd | Electrodeposition liquid composition |
| JPS5833902B2 (en) * | 1979-11-14 | 1983-07-22 | 大日本塗料株式会社 | Metal pretreatment paint composition |
-
1982
- 1982-06-01 CA CA000404249A patent/CA1178041A/en not_active Expired
- 1982-06-03 JP JP9413482A patent/JPS582361A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS582361A (en) | 1983-01-07 |
| JPH0216779B2 (en) | 1990-04-18 |
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